Effect of Modification on the Growth Morphology of Mg2Si in Mg-Si Alloy
In recent years, saving the energy sources and environment pollutionproblems have received more and more attention and effective method to solvethem is to use light-weight and high-effective materials. Magnesium alloys arekind of the lightest structural metal alloys applied in the industrial at present,which are provided with many excellent and electrical properties, such as lowdensity, high specific strength and stiffness, high heat and electrical conductivity,good damping and shock absorption, excellent electromagnetic shieldingcapability and easy processing. In the 21st century when human being put thecontinual development as the first-line problem, saving the resource and innoxiousproduction have become the trends in the world nowadays. Consequently, theunique properties of magnesium alloys accord with the above requirement by thesquare. Therefore, since the 1980s later, magnesium alloys have been becomingone of the hotspot in the research field of materials science.Alloying is the method in common use for the application of magnesium now.Compared to others metals, magnesium Special shape NdFeB magnets has especial physical metallurgyproperties, and so it is narrow that to choose the alloying elements for the alloyingof magnesium. Silicon is one of them. Since a maximum solid solubility of Si intoMg is only 0.003 at.% silicon, Si atom can react with Mg atoms and areprecipitated as an intermetallic compound of Mg2Si. Mg2Si is an effectivestrengthening phase and can improve the high temperature properties. It isnecessary to increase the Mg2Si content for receiving better strength effect.Mg-high Si alloy fabricated by conventional metallurgy method contain coarseMg2Si dendritic crystals (100~1000μm);besides, eutectic Mg2Si phase is theChinese script type particles. The Mg-Si alloys showed very low ductility andstrength. In recent years, it was reported that the mechanical properties of Mg–Sialloys could be improved by the application of advanced processing techniques,such as hot extrusion (HE), rapid solidification (RS), directional solidification (DS)and mechanical alloying (MA). The microstructure and properties of Mg-high Sialloys had a obvious improvement. However, the methods above had the shortagesboth restricted fine of grain or complex technique and the increase of theproduction cost. At the present time, it had been fabricated Mg2Si/Al-Si usingmodifiers such as RE, sodium and Sr. Modification method had got attachimportance to application. At present, the study on the modification of Mg-Sisystem focus on die-casting Mg alloy contain low Si content (commonly<1wt.%),and modified object was main eutectics Mg2Si phase. It is seldom for the study onMg-high Si alloy. So based on the modified characteristic of Mg-Si alloy,combined with existing modified processing on Al-Si and Mg-Si alloy, theexploiture and development of new modification method applied to Mg-Si alloy iscritical for its large-scale applications in industry.Based on the above standpoint and statement, modification and rapidsolidification routes is selected for the modification of Mg-Si alloy, i.e. primaryand eutectic Mg2Si phases were modified by the RE(Sm2O3、Nd2O3、Y2O3、La2O3)and KBF4, and rapid solidification such as spray casting. On the basis of thesework, effect of modification on the primary and eutectic Mg2Si phases(morphology, amount, size and distribution) in the Mg-high Si alloy have beeninvestigated detailedly.
The major research efforts of the present study are asfollows:(1) It was found by the modification on Mg-high Si alloy using RE2O3 thatthe modification effect changed as sub modified, modified and overmodified as increasing the RE2O3 content from 0.05% to 0.4%.(a) For four kind of RE2O3, Y2O3 was the best modifier on primaryMg2Si in the Mg-high Si alloy. When the Y2O3 content is 0.2wt.%,primary Mg2Si changed from dendrite(>100μm) to polyhedral shape(15μm) and distributed uniformly in the alloy. Besides, Chinese scripttype eutectic Mg2Si ruptured and changed to point shape.(b) For four kind of RE2O3, Sm2O3 was the best modifier on eutecticsMg2Si in the Mg-high Si alloy. When the Sm2O3 content is 0.2wt.%,most of eutectics Mg2Si changed to point and the size of primaryMg2Si decreased from >100μm to 20-30μm.(c) It was http://www.999magnet.com found that much white acicular phase was present in theMg-high Si alloy modified by RE2O3 and increased with theincreased of RE2O3. As the present of silicon in the melt, Mg, Si andRE were likely to reaction and replace RE from RE2O3.(2) After the composite modification using Y2O3+KBF4 and La2O3+KBF4,the size of primary Mg2Si changed to ~10μm and its morphology waspolyhedron;Most of eutectic Mg2Si changed to point shape and somewere fiber shape.(3) Y2O3 had excellent effect on Mg-high Si alloy as the Si content changedfrom 3% to 9%. For the modification effect on Mg2Si phase, the relationof Y2O3 and Si content was not linear. Y2O3 is effective on the Mg-Al-Sisystem for modification. After Y2O3 addition in the AZ91D-5% Si alloy,the size of primary Mg2Si changed from more than 100μm to 20μm.(4) Solidification rate had great influence on the growth morphology ofMg2Si phase. High solidification rate could restrain the anisotropicgrowth. If solidification rate increased, the size of primary Mg2Si woulddecrease. Besides, the morphology of primary Mg2Si was octahedron.Successful improvement of the microstructure of Mg-high Si alloy play alarge role on the advanced of high temperature properties of Mg alloy. It isexpected that the present research acts as the guidance and promotion.
2012年8月27日星期一
Theoretical Study of Upconversion Ultraviolet Laser in Pr～(3+):ZBLAN Fiber
Theoretical Study of Upconversion Ultraviolet Laser in Pr～(3+):ZBLAN Fiber
To realize upconversion UV laser in laser medium, theoretical studies ofupconversion UV laser kinetics are necessary. In this thesis, we theoreticallystudy the feasibility of realizing upconversion UV laser in Pr3+: ZBLAN fiber.Firstly, by utilizing steady population rate equations and propagationequations, we investigate the kinetics of upconversion UV laser of Pr3+ inPr3+:ZBLAN。Two pump lasers input into the fiber. One laser pumps the groundstate manifold 3H4 into an intermediate manifold 1D2.And another pump laserexcites intermediate manifold 1D2 to the upper lasing manifold 1S0. And we know,there exist the population inversions between 1S0 state and the highest Stark levelof 3F4, 3F2 ,3H4 level. But we found it is possible only between 1S0 state and thehighest Stark level of 3F4 for laser oscillator, for the too small emit-cross of 3F2 or3H4 level.The threshold pump Block Neodymium magnets powers, output power, slope efficiency and optimumcavity length are calculated and discussed. In different Pr3+ concentrations, weobserved that the high concentration makes laser oscillator with low thresholdpump powers but high slope efficiency. The threshold pump powers increaselinearly with the fiber length increased. Short fiber cavity length is better for highslope efficiency, and the best slope efficiency can be more than 16.7%. Shortcavity length and low pump powers are disadvantage to the high output power.There exists a saturation pump power to obtain optimum output power when thefiber length is given.
Given the characteristics of the laser, there exists anoptimum cavity length to obtain optimum output power.Secondly, we investigate the laser kinetics for upconversion UV in Pr3+:Ce3+:ZBLAN fiber. After two-step excitation for Pr3+ 4f5d state, energytransferring happens between Pr3+and Ce3+, then realizes laser transition fromCe3+ 5d state to the highest Stark level of 2F5/2 . And we studied two solutions forthe two-step excitation respectively, Ⅰis through intermediate manifold 1D2 andⅡ is through intermediate manifold 3P0 . As in model Ⅰ, it is known that , http://www.999magnet.com in thisfiber, the energy transferring happened,and outputted signal laser based on Ce3+5d state. But the threshold pump powers are high(more than 20W),slopeefficiency is low(less than 3%),and output power is low also(less than 0.2W).Because not all of the experiment parameters are come from ZBLAN fiber,itneeds further work for this research.In the same conditions, we compared these two laser system as bellow: ①Inboth system, threshold pump powers are high and more than 20W, but Ⅰis lowerthan Ⅱ;②T he optimum reflectivity R2 is about 80% in each system;③Slopeefficiency are low in these two laser system, when the fiber length and pumppowers are properly selected, slope efficiency tends to a optimum value, 3% insystemⅠ a nd 0.4% in system Ⅱ.④ The optimum cavity length is shorter than 1min each system.In conclusion, upconversion UV laser action is feasible to be realized inPr3+:ZBLAN fiber. But it’s difficult to realize UV laser oscillator inPr3+:Ce3+:ZBLAN fiber, by energy transferring. This thesis provides theoreticalfoundation of realizing upconversion UV laser for Pr3+ in experiment.
To realize upconversion UV laser in laser medium, theoretical studies ofupconversion UV laser kinetics are necessary. In this thesis, we theoreticallystudy the feasibility of realizing upconversion UV laser in Pr3+: ZBLAN fiber.Firstly, by utilizing steady population rate equations and propagationequations, we investigate the kinetics of upconversion UV laser of Pr3+ inPr3+:ZBLAN。Two pump lasers input into the fiber. One laser pumps the groundstate manifold 3H4 into an intermediate manifold 1D2.And another pump laserexcites intermediate manifold 1D2 to the upper lasing manifold 1S0. And we know,there exist the population inversions between 1S0 state and the highest Stark levelof 3F4, 3F2 ,3H4 level. But we found it is possible only between 1S0 state and thehighest Stark level of 3F4 for laser oscillator, for the too small emit-cross of 3F2 or3H4 level.The threshold pump Block Neodymium magnets powers, output power, slope efficiency and optimumcavity length are calculated and discussed. In different Pr3+ concentrations, weobserved that the high concentration makes laser oscillator with low thresholdpump powers but high slope efficiency. The threshold pump powers increaselinearly with the fiber length increased. Short fiber cavity length is better for highslope efficiency, and the best slope efficiency can be more than 16.7%. Shortcavity length and low pump powers are disadvantage to the high output power.There exists a saturation pump power to obtain optimum output power when thefiber length is given.
Given the characteristics of the laser, there exists anoptimum cavity length to obtain optimum output power.Secondly, we investigate the laser kinetics for upconversion UV in Pr3+:Ce3+:ZBLAN fiber. After two-step excitation for Pr3+ 4f5d state, energytransferring happens between Pr3+and Ce3+, then realizes laser transition fromCe3+ 5d state to the highest Stark level of 2F5/2 . And we studied two solutions forthe two-step excitation respectively, Ⅰis through intermediate manifold 1D2 andⅡ is through intermediate manifold 3P0 . As in model Ⅰ, it is known that , http://www.999magnet.com in thisfiber, the energy transferring happened,and outputted signal laser based on Ce3+5d state. But the threshold pump powers are high(more than 20W),slopeefficiency is low(less than 3%),and output power is low also(less than 0.2W).Because not all of the experiment parameters are come from ZBLAN fiber,itneeds further work for this research.In the same conditions, we compared these two laser system as bellow: ①Inboth system, threshold pump powers are high and more than 20W, but Ⅰis lowerthan Ⅱ;②T he optimum reflectivity R2 is about 80% in each system;③Slopeefficiency are low in these two laser system, when the fiber length and pumppowers are properly selected, slope efficiency tends to a optimum value, 3% insystemⅠ a nd 0.4% in system Ⅱ.④ The optimum cavity length is shorter than 1min each system.In conclusion, upconversion UV laser action is feasible to be realized inPr3+:ZBLAN fiber. But it’s difficult to realize UV laser oscillator inPr3+:Ce3+:ZBLAN fiber, by energy transferring. This thesis provides theoreticalfoundation of realizing upconversion UV laser for Pr3+ in experiment.
Studies on Functional Host-guest Assembly Systems Based on Layered Materials
Studies on Functional Host-guest Assembly Systems Based on Layered Materials
When a guest species is encapsulated in a host, composite host-guestcompounds with unusual properties may form. Layered inorganic materialshave been extensively consider as a good host to incorporate functional guestspecies which yield a variety of useful applications as catalyst, ion conductors,shape-selective adsorbents, ion exchangers, photofunctional materials, etc.,and many novel assembly structures can be tailored at the Segment neodymium magnets molecular levelthrough the design of the host and the guest species. In this thesis, we describesome new host-guest systems related to layered materials.1. Intercalation of DNA-Ethidium Complex into Layered DoubleHydroxide.
A new composite compound LDH-DNA-ET has been preparedthrough intercalation of ethidium and DNA molecule into the layers of layereddouble hydroxide (LDH). The LDH-DNA-ET compound has beeninvestigated by various analytical methods such as X-ray diffraction, infrared,UV-vis and circular dichroism spectroscopy, element and thermogravimetricanalyses. The interlayer distance of the LDH-DNA-ET compound is 4.6 nm,larger than that of the pristine LDH. Taking into account the structure of theDNA molecule and the ET molecule, it is proposed that there are two layers ofDNA-ET composite between two adjacent LDH sheets. The DNA moleculesin the LDH-DNA-ET compound retain their chemical and biological integrity.The LDH-DNA-ET compound gave rise to photoluminescence of λem,max=610 nm under the excitation of a laser light of λex=488 nm.LDH-DNA-ET compound has potential significance about functionalmaterials of DNA development.2. http://www.999magnet.com Lysine and Cetyltrimethyl Ammonium Bromide(CTAB) Co-intercalatedMontmorillonite and Study on Its Catalytic Action. We succeeded toIntercalate lysine (Lys) molecules and CTAB molecules into between thelayers of montmorillonite at room temperature through an ions-exchangetechnique,and the production is MLC. Powder X-ray diffraction and infraredspectrum analysis indicate that the lysine molecules and the CTAB moleculesare intercalated into between the inorganic layers. The MLC molecules isstabilized in water and the lysine molecules and CTAB molecules can notescape from the layer. The MLC composite in combination with benzaldehydeand chloroform has also been applied in the reaction as a catalyst. However,the regathered MLC molecules showed high catalytic activity for the reaction.So, the catalyst’s repetition is not impossible.
When a guest species is encapsulated in a host, composite host-guestcompounds with unusual properties may form. Layered inorganic materialshave been extensively consider as a good host to incorporate functional guestspecies which yield a variety of useful applications as catalyst, ion conductors,shape-selective adsorbents, ion exchangers, photofunctional materials, etc.,and many novel assembly structures can be tailored at the Segment neodymium magnets molecular levelthrough the design of the host and the guest species. In this thesis, we describesome new host-guest systems related to layered materials.1. Intercalation of DNA-Ethidium Complex into Layered DoubleHydroxide.
A new composite compound LDH-DNA-ET has been preparedthrough intercalation of ethidium and DNA molecule into the layers of layereddouble hydroxide (LDH). The LDH-DNA-ET compound has beeninvestigated by various analytical methods such as X-ray diffraction, infrared,UV-vis and circular dichroism spectroscopy, element and thermogravimetricanalyses. The interlayer distance of the LDH-DNA-ET compound is 4.6 nm,larger than that of the pristine LDH. Taking into account the structure of theDNA molecule and the ET molecule, it is proposed that there are two layers ofDNA-ET composite between two adjacent LDH sheets. The DNA moleculesin the LDH-DNA-ET compound retain their chemical and biological integrity.The LDH-DNA-ET compound gave rise to photoluminescence of λem,max=610 nm under the excitation of a laser light of λex=488 nm.LDH-DNA-ET compound has potential significance about functionalmaterials of DNA development.2. http://www.999magnet.com Lysine and Cetyltrimethyl Ammonium Bromide(CTAB) Co-intercalatedMontmorillonite and Study on Its Catalytic Action. We succeeded toIntercalate lysine (Lys) molecules and CTAB molecules into between thelayers of montmorillonite at room temperature through an ions-exchangetechnique,and the production is MLC. Powder X-ray diffraction and infraredspectrum analysis indicate that the lysine molecules and the CTAB moleculesare intercalated into between the inorganic layers. The MLC molecules isstabilized in water and the lysine molecules and CTAB molecules can notescape from the layer. The MLC composite in combination with benzaldehydeand chloroform has also been applied in the reaction as a catalyst. However,the regathered MLC molecules showed high catalytic activity for the reaction.So, the catalyst’s repetition is not impossible.
Tunable Fiber Laser Bassed on Fabry-Perot Filter
Tunable Fiber Laser Bassed on Fabry-Perot Filter
Optoelectronic components are the key techniques for next generation of AllOptical Net (AON). In the recent years, with the development of the techniques ofAON, its core devices have been improved, so the optical fiber communicationbecame stable and flexible increasingly. However some of the key opticalcomponents are not well developed, which limits the future improvement ofOptical Net. With the demand of big capacity and high speed of optical fibrecommunication, the dynamic tunable optical source on a certain optical frequencyband is needed. Therefore tunable broadband optical fiber laser have become theresearch focus and frontier in laser techniques. The dynamic tunable wavelength laser can provide optical source formulti-channels at the same time, which makes the design of the emission terminalmore compact and economical. It can save backup Alnico magnets quantity and specification ofoptical source, and be easy to standardize the communication system, so therunning and maintenance cost of the systems can be reduced greatly. The tunablelaser can be used as not only optical source of DWDM system, but also PSE andLambda Router etc. It has great potential for optical communication and in thefuture the current fixed wavelength laser will be replaced by it. The tunable fiberlaser can also provide good optical source for all kinds of sensor systems andmodern spectrum techniques. Nowadays most of the lasers for communication are semiconductor lasers,which cost much and hard to couple into transfer fiber for the same size, so as tolimit further development of optical fiber communication. Semiconductor laser diode (LD) has several ways of tuning, such as electronictuning, thermal tuning and mechanical tuning etc. It can be divided into outer andinner cavity multi-electrode. However all kinds of tuning methods exist someweakness, which cannot be eliminated, such as wavelength stability reducing bythermal effect, which causes mode pulling etc. With the increasing of number ofthe channel, the semiconductor laser has to be increased. It will cost more, be hardto control wavelength and reach the requirement of the WDM wavelength standardintroduced by ITU – T. What’s more it also causes problem of reliability.The optical fiber laser is better than the semiconductor laser in the followingaspects:1. The cheaper diode laser pumping the doped fiber is used, which can reduce thecost of the system;2. Fiber laser is easy to couple into transfer fiber for the same size;3. Fiber laser can be more cooler for the high area-cubage ratio;4. The wide band wavelength (380 – 3900nm) output can be obtained, which isvery important for DWDM system;5. Fiber laser and fiber amplifier is compatible with current fiber components, soit is possible to setup all optical transfer system.The gain broad band is the highlight of all advantages of the fiber laser. Due toits advantages of less coupling loss, all compatibility with optical fiber, lowpolarization relativity, high stability and low cost, the tunable Er-doped fiber laseris of significant practical value in the fields of wavelength division multiplexer(WDM) and time division multiplexer (TDM) optical fiber communication network,optical fiber sensor system and modern spectrum techniques.
The ways to achieve variable wavelength http://www.999magnet.com output are as follows: rotatablegrating as end mirror, standard filter with adjustable angle, liquid crystal standardfilter, acousto-optic filter, F-P filter, M-Z interference filter and multiplex annularresonant cavity etc.The tunable optical fiber laser based on F-P filter is designed and developed. Ituses fiber Fabry-Perot filter as the device for wavelength tuning. The test carriedout through software simulation and optimization of related components so as toshorten the test cycle and reduce the cost. During the test it used Erbium-dopedfiber as gain medium and F-P filter as tuning component. It is ring cavity and uses1480nm laser diode as pump source. Through selecting reasonable parameter, itoptimizes the configuration of laser resonant cavity, reduces threshold value ofpump source of laser and improves slope efficiency and output power. The workingwavelength of laser is 1550nm, linewidth is less than 0.2nm in 3dB and 0.4nm in25dB, edge-mode suppression ratio is more than 50dB. After 1 hr testing, thewavelength doesn’t wave, and its stability is better than 0.01nm. The laser outputduring the whole tuning process is no chirped. The continuous tuning range is1525nm – 1560.3nm (35.3nm), the spectrum band width keeps the same while thewavelength changing. The peak values of laser wavelength are flat. When thewavelength is shorter than 1530nm, http://www.999magnet.com ASE noise increases, however thesignal-to-noise ratio is still higher than 57dB. The reason of above is because theEr-doped laser has a higher absorption peak at the point of 1530nm. Due to theselection of erbium fiber laser of optimal length, and two isolators to reduce thenoise in the fiber loop, which increases the signal-to-noise ratio, the maximumoutput power is 80.72mW, stability of power is better than ±0.02dB and slopeefficiency of laser is 42.83%.This laser is with the advantages of high power, low threshold value, narrowline width and good stability of performance. The center wavelength can be choice,wideband tuning, high wavelength resolution, high stability, small size andreasonable performance to price ratio.
Optoelectronic components are the key techniques for next generation of AllOptical Net (AON). In the recent years, with the development of the techniques ofAON, its core devices have been improved, so the optical fiber communicationbecame stable and flexible increasingly. However some of the key opticalcomponents are not well developed, which limits the future improvement ofOptical Net. With the demand of big capacity and high speed of optical fibrecommunication, the dynamic tunable optical source on a certain optical frequencyband is needed. Therefore tunable broadband optical fiber laser have become theresearch focus and frontier in laser techniques. The dynamic tunable wavelength laser can provide optical source formulti-channels at the same time, which makes the design of the emission terminalmore compact and economical. It can save backup Alnico magnets quantity and specification ofoptical source, and be easy to standardize the communication system, so therunning and maintenance cost of the systems can be reduced greatly. The tunablelaser can be used as not only optical source of DWDM system, but also PSE andLambda Router etc. It has great potential for optical communication and in thefuture the current fixed wavelength laser will be replaced by it. The tunable fiberlaser can also provide good optical source for all kinds of sensor systems andmodern spectrum techniques. Nowadays most of the lasers for communication are semiconductor lasers,which cost much and hard to couple into transfer fiber for the same size, so as tolimit further development of optical fiber communication. Semiconductor laser diode (LD) has several ways of tuning, such as electronictuning, thermal tuning and mechanical tuning etc. It can be divided into outer andinner cavity multi-electrode. However all kinds of tuning methods exist someweakness, which cannot be eliminated, such as wavelength stability reducing bythermal effect, which causes mode pulling etc. With the increasing of number ofthe channel, the semiconductor laser has to be increased. It will cost more, be hardto control wavelength and reach the requirement of the WDM wavelength standardintroduced by ITU – T. What’s more it also causes problem of reliability.The optical fiber laser is better than the semiconductor laser in the followingaspects:1. The cheaper diode laser pumping the doped fiber is used, which can reduce thecost of the system;2. Fiber laser is easy to couple into transfer fiber for the same size;3. Fiber laser can be more cooler for the high area-cubage ratio;4. The wide band wavelength (380 – 3900nm) output can be obtained, which isvery important for DWDM system;5. Fiber laser and fiber amplifier is compatible with current fiber components, soit is possible to setup all optical transfer system.The gain broad band is the highlight of all advantages of the fiber laser. Due toits advantages of less coupling loss, all compatibility with optical fiber, lowpolarization relativity, high stability and low cost, the tunable Er-doped fiber laseris of significant practical value in the fields of wavelength division multiplexer(WDM) and time division multiplexer (TDM) optical fiber communication network,optical fiber sensor system and modern spectrum techniques.
The ways to achieve variable wavelength http://www.999magnet.com output are as follows: rotatablegrating as end mirror, standard filter with adjustable angle, liquid crystal standardfilter, acousto-optic filter, F-P filter, M-Z interference filter and multiplex annularresonant cavity etc.The tunable optical fiber laser based on F-P filter is designed and developed. Ituses fiber Fabry-Perot filter as the device for wavelength tuning. The test carriedout through software simulation and optimization of related components so as toshorten the test cycle and reduce the cost. During the test it used Erbium-dopedfiber as gain medium and F-P filter as tuning component. It is ring cavity and uses1480nm laser diode as pump source. Through selecting reasonable parameter, itoptimizes the configuration of laser resonant cavity, reduces threshold value ofpump source of laser and improves slope efficiency and output power. The workingwavelength of laser is 1550nm, linewidth is less than 0.2nm in 3dB and 0.4nm in25dB, edge-mode suppression ratio is more than 50dB. After 1 hr testing, thewavelength doesn’t wave, and its stability is better than 0.01nm. The laser outputduring the whole tuning process is no chirped. The continuous tuning range is1525nm – 1560.3nm (35.3nm), the spectrum band width keeps the same while thewavelength changing. The peak values of laser wavelength are flat. When thewavelength is shorter than 1530nm, http://www.999magnet.com ASE noise increases, however thesignal-to-noise ratio is still higher than 57dB. The reason of above is because theEr-doped laser has a higher absorption peak at the point of 1530nm. Due to theselection of erbium fiber laser of optimal length, and two isolators to reduce thenoise in the fiber loop, which increases the signal-to-noise ratio, the maximumoutput power is 80.72mW, stability of power is better than ±0.02dB and slopeefficiency of laser is 42.83%.This laser is with the advantages of high power, low threshold value, narrowline width and good stability of performance. The center wavelength can be choice,wideband tuning, high wavelength resolution, high stability, small size andreasonable performance to price ratio.
Preparation and Characterization of Nanometer ITO Materials
Preparation and Characterization of Nanometer ITO Materials
Nanometer ITO powders were prepared by homogeneous precipitation method in this paper, with In、 SnCl4·5H2O being the raw materials and urea being the precipitant. Thermal analysis、 XRD、 TEM、 IR、 UV-VIS and digital bridge were used to characterize the changes of the ITO precursor when being heated, the ITO particle phase、 shape、 size distribution、 optical and electrical property. The influences of nine factors, including Neodymium Magnets reactants ratio 、 composition、 initial pH value、 anti-aggregative agent 、 reaction time and temperature、 the dripping method、 way of dehydration and sintering temperature, on the particle size、 shape and property were investigated systematically, and finally a optimization process was obtained. The study showed that this process, which can produce fine ITO particles, was not only easy to master, but also had a prospect for industrialization. Compared with common ITO material, the particle prepared by this method presented better optical properties due to the small-size effect, which has a stronger reflectivity on infrared radiation ( ≥ 99% )、 transmission on visible radiation (≥99.99%) and absorptvity on ultraviolet radiation (ABS≥1.0) .The influence of rare element Nd , when doped into ITO powders, on the particle size 、 shape and property were also studied. The result showed that within 3% doped amount of Nd2O3, in terms of morphology, the particle size decreased with the increasing http://www.999magnet.com amount of Nd2O3;in terms of optical property, the particle presented changes as follows: the infrared absorption peak situated between 500 and 1000cm-1 blue shifted in infrared wave band, no obvious change in visible wave band, absorptvity increased and absorption strip extended in ultraviolet wave band;in terms of electrical property, the resistivity soared as the doping amount increased.
Nanometer ITO powders were prepared by homogeneous precipitation method in this paper, with In、 SnCl4·5H2O being the raw materials and urea being the precipitant. Thermal analysis、 XRD、 TEM、 IR、 UV-VIS and digital bridge were used to characterize the changes of the ITO precursor when being heated, the ITO particle phase、 shape、 size distribution、 optical and electrical property. The influences of nine factors, including Neodymium Magnets reactants ratio 、 composition、 initial pH value、 anti-aggregative agent 、 reaction time and temperature、 the dripping method、 way of dehydration and sintering temperature, on the particle size、 shape and property were investigated systematically, and finally a optimization process was obtained. The study showed that this process, which can produce fine ITO particles, was not only easy to master, but also had a prospect for industrialization. Compared with common ITO material, the particle prepared by this method presented better optical properties due to the small-size effect, which has a stronger reflectivity on infrared radiation ( ≥ 99% )、 transmission on visible radiation (≥99.99%) and absorptvity on ultraviolet radiation (ABS≥1.0) .The influence of rare element Nd , when doped into ITO powders, on the particle size 、 shape and property were also studied. The result showed that within 3% doped amount of Nd2O3, in terms of morphology, the particle size decreased with the increasing http://www.999magnet.com amount of Nd2O3;in terms of optical property, the particle presented changes as follows: the infrared absorption peak situated between 500 and 1000cm-1 blue shifted in infrared wave band, no obvious change in visible wave band, absorptvity increased and absorption strip extended in ultraviolet wave band;in terms of electrical property, the resistivity soared as the doping amount increased.
2012年8月23日星期四
Geological Characteristics and Metallogenic Model of the Wunugetushan Porphyry Cu-Mo Deposit, Inner Mongolia
Geological Characteristics and Metallogenic Model of the Wunugetushan Porphyry Cu-Mo Deposit, Inner Mongolia
Copper-milybdenum ore zone locates in Manchouli City southwest22kilometer department, the work area scope schedule is about 9.54squarekilometer, administrative division belongs to Mongoliamunicipality Xinbarhufight county geographical coordinates:eastlongitude 117°14ˊ~117° 22ˊ;north lantitude 49° 22ˊ~49° 30ˊ from Manchouli City to mining area therehave got three grasslandthoroughfaresand railways gone to all parts of thecountry, traffickingis convenient. The studied area lies in the southeast exterior margin of Siberianplate. Itbelongs to the transitional crust tectonic province betweenSiberian plate and Sino-Korean plate. There are antique fold baseformed with Proterzoic and Cambrian Era in crustal structure developedhistory. Cracking occurred after orogenic movement in Caledon.Geosynclinal deposits construst in the Devonian to theCarboniferous-Permian Period developed at late Paleozoic. In contrastto Mongolia and Russia materials, it dues to the outer Alnico magnets Baikal fold scope,whose boundary is Erguna-Hulun deep rupture in the fold belt inDahingganling. This fracture belt is a very important tectonic belt.(Zhao suggests that it is a joined tectonics between Siberia Plate andNorth Plate.) It joined the deep fracture of mid-Mongolia in south,side and Ehuocike in north side. Derpugan fracture which controlsregion mineralization is its branch. With systemly collection and predecessors’ research works, theauthor summarized the tectonic setting, ore-bearing character,deposit geology and geochemical character of Wunugetucopper-milybdenum deposit and explored metallogenic origin and builtmodels according to the field and other delicate studies. Combined withcurrent new porphyry theory, the author suggested that Wunugetucopper-milybdenum ore possesses adakite character for the first time.It contributes widen clues for prospecting. The studied results areas follows: Wunugetu copper-milybdenum locates in the west of Erguna-Hulundeep fracture, the communicated complex section between outer Baikaland Dahingganling geosynclinal folded system. The deposit occurredMesozosic lava strap bulging area. The strata in region are DevonianWunur Group and Jurassic Shangkuli Group etc. The most of the formerare sand slate andesite and the latter are basaltic andesite, dacite,rhyolite and clastic lava.Mid-acid magma active intensively in region. The intensiveactivity and widest distribution are famous for dacite porphyry,quarts porphyry, monzograntic porphyry and granite porphyryetc.Copper-milybdenum minerali-zation is associated with plagioclasegranite. Ore-beating bodies are shallow sub-plagioclase granite andgranite porphyry. It is in the volcanic aisle. Granite porphyry exsitsin remains in breccia rock ripe. The age of the ore-bearing is 138Ma.Ore-bearing bodies have intensive alteration and arecharacteristiced in departed belts. Quartz-Kalium alteration mostlygrown in the centre of rock bodies altered minerals composed of quartz,potash feldspar, sericite grade etc, parts of them accompanied withpaulopost alteration superposd damourite, illite grade;quartz-sericite-damourite belt lay out side of quartz-potash belt, theshape was the same with quartz-potash belt and occurred in tiltbarrel,which was characteristic in sericite+damourite>30%,illite-damourite belt appeared exterior margin, typical character http://www.999magnet.com wasillite+damourite>30%. The three alteration zones above mentioneddistributed in subconcentric ring, under F7 fault movement influence,formed two half ring, constituted south and north two ore blocks.Judging from character of major elements, the alteration ofstudied area were charactered in displaced type, centrosymmetry seriesand surficial shape in K+,Si4+, OH-. With the alteration intensive K+,Si4+, OH-contents which carried in and Na+, A13+, Ca2+, Mg2+, Fe2+contents which took out increased. K and Na, Si, A1 showed negativecorreation;short ofpropylite alteration.Suffering from Copper-Milybdenum ore bodies F7 fold impacted formsouth and north two ore belts.Mining area altogether proved copper oreshell 33 strip, Mo minerals shell 13 strip. Cu-Mo ore bodies conditionshowed tingwise (stagger showed for horseshoe).
The whole trendnortheast, incline NW, inclined angle steeper (60°~85°), loop length1300~2550m, depth extent 150~650m,thickness 350m.Most ore mineral for chalcopyrite, molybdenite, pyrite andmagnetite, secondly for galena, blende, bitreous copper, hematiteand/or cuprttrn, molyb-denic secondary mineral. Ore structure werecharactered in veinlet, disseminated-veinlet, disseminated. Oretexture include acinose structure, metasomatic texture, containstructure, breakdown of solid solution structure, foliated texture andrimmed texture grade. The main metallogenic element in ore for Cu(0.2%~0.6%, supreme 2.08%), Mo (0.02%~0.06%, supreme 0.95%),accompanied elements have Au, Ag, Re, In, Se, Bi, Pb, Zn etc, whichRe, Ag, Au approved complex utilization.Rock (mine) anlitical resulting displayed that the magmatite ofthe studied area belonged to cala-alki aluminum suprestatured sties,which showed the same magma source evolution. They all formed inorogenic environment. The rare earth element of rocks (mines) impliedthat ore bodies and surround rock’s REE transformation possessedcomplementarity in the course of hydrothermal alteration. Depleted Euhas indicated meaning to Cu-Mo ore alteration. The geochemistrycharacter of ore bodies indicated adakite rock’s property. The oresulfur, hydrogen, oxygen istope characters reflected that mineralsubstances, http://www.999magnet.com mine source were associated with magmatic activity.Ore-forming fluid’s research reflect Mo formational temperature were317~455℃, averaged in 380℃;Cu formational temperature were 324~410℃, averaged in 364℃. Ore-forming fluid salinity were 9~14wt%, whichsupreme reached 42~68wt%. Different alteration and ore belt, thetemperature, salinity, density, ratio of gas and liuid of ore-forming,all of them indicate Wunugetu mountain Cu-Mo deposits arerepresentative porphyry types ore deposits and based on those we setup metal-logenic model. The result of research indicate secondaryhypabyssal plagioclass granite porphyry, intensive zonal alterationand depleted in Eu, can look as prospected symbol of porphyry Cu-Modeposit in this area.
Copper-milybdenum ore zone locates in Manchouli City southwest22kilometer department, the work area scope schedule is about 9.54squarekilometer, administrative division belongs to Mongoliamunicipality Xinbarhufight county geographical coordinates:eastlongitude 117°14ˊ~117° 22ˊ;north lantitude 49° 22ˊ~49° 30ˊ from Manchouli City to mining area therehave got three grasslandthoroughfaresand railways gone to all parts of thecountry, traffickingis convenient. The studied area lies in the southeast exterior margin of Siberianplate. Itbelongs to the transitional crust tectonic province betweenSiberian plate and Sino-Korean plate. There are antique fold baseformed with Proterzoic and Cambrian Era in crustal structure developedhistory. Cracking occurred after orogenic movement in Caledon.Geosynclinal deposits construst in the Devonian to theCarboniferous-Permian Period developed at late Paleozoic. In contrastto Mongolia and Russia materials, it dues to the outer Alnico magnets Baikal fold scope,whose boundary is Erguna-Hulun deep rupture in the fold belt inDahingganling. This fracture belt is a very important tectonic belt.(Zhao suggests that it is a joined tectonics between Siberia Plate andNorth Plate.) It joined the deep fracture of mid-Mongolia in south,side and Ehuocike in north side. Derpugan fracture which controlsregion mineralization is its branch. With systemly collection and predecessors’ research works, theauthor summarized the tectonic setting, ore-bearing character,deposit geology and geochemical character of Wunugetucopper-milybdenum deposit and explored metallogenic origin and builtmodels according to the field and other delicate studies. Combined withcurrent new porphyry theory, the author suggested that Wunugetucopper-milybdenum ore possesses adakite character for the first time.It contributes widen clues for prospecting. The studied results areas follows: Wunugetu copper-milybdenum locates in the west of Erguna-Hulundeep fracture, the communicated complex section between outer Baikaland Dahingganling geosynclinal folded system. The deposit occurredMesozosic lava strap bulging area. The strata in region are DevonianWunur Group and Jurassic Shangkuli Group etc. The most of the formerare sand slate andesite and the latter are basaltic andesite, dacite,rhyolite and clastic lava.Mid-acid magma active intensively in region. The intensiveactivity and widest distribution are famous for dacite porphyry,quarts porphyry, monzograntic porphyry and granite porphyryetc.Copper-milybdenum minerali-zation is associated with plagioclasegranite. Ore-beating bodies are shallow sub-plagioclase granite andgranite porphyry. It is in the volcanic aisle. Granite porphyry exsitsin remains in breccia rock ripe. The age of the ore-bearing is 138Ma.Ore-bearing bodies have intensive alteration and arecharacteristiced in departed belts. Quartz-Kalium alteration mostlygrown in the centre of rock bodies altered minerals composed of quartz,potash feldspar, sericite grade etc, parts of them accompanied withpaulopost alteration superposd damourite, illite grade;quartz-sericite-damourite belt lay out side of quartz-potash belt, theshape was the same with quartz-potash belt and occurred in tiltbarrel,which was characteristic in sericite+damourite>30%,illite-damourite belt appeared exterior margin, typical character http://www.999magnet.com wasillite+damourite>30%. The three alteration zones above mentioneddistributed in subconcentric ring, under F7 fault movement influence,formed two half ring, constituted south and north two ore blocks.Judging from character of major elements, the alteration ofstudied area were charactered in displaced type, centrosymmetry seriesand surficial shape in K+,Si4+, OH-. With the alteration intensive K+,Si4+, OH-contents which carried in and Na+, A13+, Ca2+, Mg2+, Fe2+contents which took out increased. K and Na, Si, A1 showed negativecorreation;short ofpropylite alteration.Suffering from Copper-Milybdenum ore bodies F7 fold impacted formsouth and north two ore belts.Mining area altogether proved copper oreshell 33 strip, Mo minerals shell 13 strip. Cu-Mo ore bodies conditionshowed tingwise (stagger showed for horseshoe).
The whole trendnortheast, incline NW, inclined angle steeper (60°~85°), loop length1300~2550m, depth extent 150~650m,thickness 350m.Most ore mineral for chalcopyrite, molybdenite, pyrite andmagnetite, secondly for galena, blende, bitreous copper, hematiteand/or cuprttrn, molyb-denic secondary mineral. Ore structure werecharactered in veinlet, disseminated-veinlet, disseminated. Oretexture include acinose structure, metasomatic texture, containstructure, breakdown of solid solution structure, foliated texture andrimmed texture grade. The main metallogenic element in ore for Cu(0.2%~0.6%, supreme 2.08%), Mo (0.02%~0.06%, supreme 0.95%),accompanied elements have Au, Ag, Re, In, Se, Bi, Pb, Zn etc, whichRe, Ag, Au approved complex utilization.Rock (mine) anlitical resulting displayed that the magmatite ofthe studied area belonged to cala-alki aluminum suprestatured sties,which showed the same magma source evolution. They all formed inorogenic environment. The rare earth element of rocks (mines) impliedthat ore bodies and surround rock’s REE transformation possessedcomplementarity in the course of hydrothermal alteration. Depleted Euhas indicated meaning to Cu-Mo ore alteration. The geochemistrycharacter of ore bodies indicated adakite rock’s property. The oresulfur, hydrogen, oxygen istope characters reflected that mineralsubstances, http://www.999magnet.com mine source were associated with magmatic activity.Ore-forming fluid’s research reflect Mo formational temperature were317~455℃, averaged in 380℃;Cu formational temperature were 324~410℃, averaged in 364℃. Ore-forming fluid salinity were 9~14wt%, whichsupreme reached 42~68wt%. Different alteration and ore belt, thetemperature, salinity, density, ratio of gas and liuid of ore-forming,all of them indicate Wunugetu mountain Cu-Mo deposits arerepresentative porphyry types ore deposits and based on those we setup metal-logenic model. The result of research indicate secondaryhypabyssal plagioclass granite porphyry, intensive zonal alterationand depleted in Eu, can look as prospected symbol of porphyry Cu-Modeposit in this area.
Chronology and Geochemical Characteristcs of Chibosong Mafic-ultramafic Rocks from Tonghua and Its Constraints on Ore-forming Process
Chronology and Geochemical Characteristcs of Chibosong Mafic-ultramafic Rocks from Tonghua and Its Constraints on Ore-forming Process
A lot of mafic-ultramafic intrusives occur in Chibosong area in Tonghuaregion, Jilin province. The Chibosong-Ⅰintrusive is the most important one inthem due to occurrence of the copper-nickel deposits. Based on the former’sstudying, chronology and geochemistry of Chibosong mafic-ultramafic rocks arestudied in this paper. The major achievements are as followings.1. Chronology of Chibosong mafic-ultramafic rocks SHRIMP zircon U-Pb dating from Chibosong gabbro in Chobosong Ⅰintrusive indicates that euhedrel and irregular zircons yield several group ofconcordia ages, i.e. 2497±13Ma, 787±35Ma, 321±10Ma (six spots), 217±11Ma (two spots), and 134±7Ma (four spots). On the basis of analyses of zirconCL images and regional tectonics, the age of 134±7Ma is considered to be theemplacing age of Chibosong mafic-ultramafic rocks.2. Rock series and origin of Chibosong intrusiveThe major element data of Chibosong mafic-ultramafic rocks indicate thatthey Neodymium Magnets belong to sub-alkali series and low-potassium tholeiitic series, and displaytholeiitic evolutionary series.Petrography and geochemistry of Chibosong mafic-ultramafic rocks suggestthat they should be resulted from the accumulation of mafic magma.3 Magma resource and its nature for Chibosong mafic-multramafic rocksThe Mg# values for Chibosong peridotite and gabbro range from 61 to 78.Sc , Co, and Ni contents for them are from 21.85 to 34.22, 66.22 to 207.57, and194.90 to 4699.67, respectively.
The evidence mentioned above implies thatChibosong mafic-multramafic rocks should be of characteristics of primarymagma and could be derived from partial melting of peridorite in enrichedmantle. Sr-Nd isotopic compositions of the mafic-ultramafic rocks, such as Isrvalues ranging from 0.7063 to 0.7088 and the negative εNd(t) values, alsodemonstrate above-mentioned consideration. In addition, Sr-Nd isotopiccompositions for the mafic-ultramafic rocks, together with Archean inheritedzircons in them, shows that intensive crustal hybridization could took placeduring the formation and evolution of the primary magma, which is also provedby the depletion of high-field strenghth elements in them.4. Tectonic background of formation of Chibosong mafic-ultrafic rocksBoth http://www.999magnet.com major and minor elements in the Chibosong intrusive indicate thatthey could formed in the active continental margin. On the other hand, theoccurrence of contemporary syenite porhyry dykes in this region, together withmafic-ultramafic dykes, constitute the bimodal magmatism in the region,implying an intensive extensional tectonic environment. This tectonicenvironment could be consistent with the peak stage of lithospheric thinning inMesozoic period. Many Mesozoic basins and large-scale metal mineralizationalso formed during this period. Mesozoic large-scaletectonic-magmatism-mineralization should be associated with the subductionof the paleo-Pacific plate.5. Relationship between Chibosong mafic-ultramafic magmatism andmetallogenetic processThe deep differentiation of mafic-ultrafic primary magma should beresponsible for the formation of ore-forming hydrothermal fluid. The pulseintrusion of differentiated magma results in distribution of intrusive phases. Thelatter furthur controls the occurrence of disseminated copper-nickelmineralization. However, the structural fractures formed in the late stage ofmagmatism restrict the Cu-Ni vein mineralization.
A lot of mafic-ultramafic intrusives occur in Chibosong area in Tonghuaregion, Jilin province. The Chibosong-Ⅰintrusive is the most important one inthem due to occurrence of the copper-nickel deposits. Based on the former’sstudying, chronology and geochemistry of Chibosong mafic-ultramafic rocks arestudied in this paper. The major achievements are as followings.1. Chronology of Chibosong mafic-ultramafic rocks SHRIMP zircon U-Pb dating from Chibosong gabbro in Chobosong Ⅰintrusive indicates that euhedrel and irregular zircons yield several group ofconcordia ages, i.e. 2497±13Ma, 787±35Ma, 321±10Ma (six spots), 217±11Ma (two spots), and 134±7Ma (four spots). On the basis of analyses of zirconCL images and regional tectonics, the age of 134±7Ma is considered to be theemplacing age of Chibosong mafic-ultramafic rocks.2. Rock series and origin of Chibosong intrusiveThe major element data of Chibosong mafic-ultramafic rocks indicate thatthey Neodymium Magnets belong to sub-alkali series and low-potassium tholeiitic series, and displaytholeiitic evolutionary series.Petrography and geochemistry of Chibosong mafic-ultramafic rocks suggestthat they should be resulted from the accumulation of mafic magma.3 Magma resource and its nature for Chibosong mafic-multramafic rocksThe Mg# values for Chibosong peridotite and gabbro range from 61 to 78.Sc , Co, and Ni contents for them are from 21.85 to 34.22, 66.22 to 207.57, and194.90 to 4699.67, respectively.
The evidence mentioned above implies thatChibosong mafic-multramafic rocks should be of characteristics of primarymagma and could be derived from partial melting of peridorite in enrichedmantle. Sr-Nd isotopic compositions of the mafic-ultramafic rocks, such as Isrvalues ranging from 0.7063 to 0.7088 and the negative εNd(t) values, alsodemonstrate above-mentioned consideration. In addition, Sr-Nd isotopiccompositions for the mafic-ultramafic rocks, together with Archean inheritedzircons in them, shows that intensive crustal hybridization could took placeduring the formation and evolution of the primary magma, which is also provedby the depletion of high-field strenghth elements in them.4. Tectonic background of formation of Chibosong mafic-ultrafic rocksBoth http://www.999magnet.com major and minor elements in the Chibosong intrusive indicate thatthey could formed in the active continental margin. On the other hand, theoccurrence of contemporary syenite porhyry dykes in this region, together withmafic-ultramafic dykes, constitute the bimodal magmatism in the region,implying an intensive extensional tectonic environment. This tectonicenvironment could be consistent with the peak stage of lithospheric thinning inMesozoic period. Many Mesozoic basins and large-scale metal mineralizationalso formed during this period. Mesozoic large-scaletectonic-magmatism-mineralization should be associated with the subductionof the paleo-Pacific plate.5. Relationship between Chibosong mafic-ultramafic magmatism andmetallogenetic processThe deep differentiation of mafic-ultrafic primary magma should beresponsible for the formation of ore-forming hydrothermal fluid. The pulseintrusion of differentiated magma results in distribution of intrusive phases. Thelatter furthur controls the occurrence of disseminated copper-nickelmineralization. However, the structural fractures formed in the late stage ofmagmatism restrict the Cu-Ni vein mineralization.
Co-precipitation Synthesis and Study of Long Afterglow Phosphors
Co-precipitation Synthesis and Study of Long Afterglow Phosphors
Long afterglow luminescence materials, which have excellent luminescent properties have been widely investigated and application. It appears some new synthesized methods to effectively improve the luminescent property with the new luminescent materials of the rare earth come forth.hi this paper, the Y2O2S:R3+,Mg2+,Ti4+(R3+=Eu3+,Sm3+,Tb3+) phosphors were synthesized first by co-precipitation method. Its x-ray diffraction patterns, the magnet lifter structure of crystal lattice and the luminescent properties were studied. Compared with the Y2O2S:Eu3+,Mg2+,Ti4+ phosphorescence prepared by high temperature solid state method, we can see that the phosphors prepared by co-precipitation method not only have small granularity and loosen structure but also can made the Eu3+ enter into crystal lattice and form luminescent centre easily. So the luminescent properties of Y2O2S:Eu3+,Mg2+,Ti4+can improve effectively.
The change of emission spectra in Y2O2S:Sm3+,Mg2+,Ti4+and Y2O2S:Tb3+,Mg2+,Ti4+ were studied though altering the concentration of activator. The emission spectra of Y2O2S:Sm3+,Mg2+,Ti4+ increased with the increasing of Sm3+. In the emission spectra of Y2O2S:Tb3+,Mg2+,Ti4+ phosphors, the spectra rooted in the 5D4→7Fs increased straight and the spectra come from 5D3→7F5 increased firstly and decreased afterwards with the increased http://www.999magnet.com of Tb3+. The intensity was the strongest when the concentration of Tb3+ is 2.0%.The long afterglow phosphor (Ca1-xSrx)S:Eu2+ was fabricated by co-precipitation. The effect of the ratio of Ca2+ and Sr2+ on the crystal lattice and the effect of the concentration of Eu2+ on the luminescent properties through the analysis of XRD, excitation and emission. The blue shifts were observed when Sr2+ increased. The luminescent properties reach the best when the concentration of Eu2+ is 0.6% and the sintering temperature is 1100℃.Through these investigations in this paper, it made us have more realize and understand for the long afterglow materials by co-precipitation method and offer important experiment foundation for more study the formation method of this material.
Long afterglow luminescence materials, which have excellent luminescent properties have been widely investigated and application. It appears some new synthesized methods to effectively improve the luminescent property with the new luminescent materials of the rare earth come forth.hi this paper, the Y2O2S:R3+,Mg2+,Ti4+(R3+=Eu3+,Sm3+,Tb3+) phosphors were synthesized first by co-precipitation method. Its x-ray diffraction patterns, the magnet lifter structure of crystal lattice and the luminescent properties were studied. Compared with the Y2O2S:Eu3+,Mg2+,Ti4+ phosphorescence prepared by high temperature solid state method, we can see that the phosphors prepared by co-precipitation method not only have small granularity and loosen structure but also can made the Eu3+ enter into crystal lattice and form luminescent centre easily. So the luminescent properties of Y2O2S:Eu3+,Mg2+,Ti4+can improve effectively.
The change of emission spectra in Y2O2S:Sm3+,Mg2+,Ti4+and Y2O2S:Tb3+,Mg2+,Ti4+ were studied though altering the concentration of activator. The emission spectra of Y2O2S:Sm3+,Mg2+,Ti4+ increased with the increasing of Sm3+. In the emission spectra of Y2O2S:Tb3+,Mg2+,Ti4+ phosphors, the spectra rooted in the 5D4→7Fs increased straight and the spectra come from 5D3→7F5 increased firstly and decreased afterwards with the increased http://www.999magnet.com of Tb3+. The intensity was the strongest when the concentration of Tb3+ is 2.0%.The long afterglow phosphor (Ca1-xSrx)S:Eu2+ was fabricated by co-precipitation. The effect of the ratio of Ca2+ and Sr2+ on the crystal lattice and the effect of the concentration of Eu2+ on the luminescent properties through the analysis of XRD, excitation and emission. The blue shifts were observed when Sr2+ increased. The luminescent properties reach the best when the concentration of Eu2+ is 0.6% and the sintering temperature is 1100℃.Through these investigations in this paper, it made us have more realize and understand for the long afterglow materials by co-precipitation method and offer important experiment foundation for more study the formation method of this material.
2012年8月20日星期一
The Design of Universal Developing Platform for Motor Control
The Design of Universal Developing Platform for Motor Control
With the increasing demands for the motor control technology, common MCU can’t satisfy the control demands. However, the development of DSP technology can strongly support the implementation of advanced control theory and complex control algorithm. But in the development of motor control based on DSP, there are such many deficiencies as low efficiency and more needs for professional knowledge.Therefore, based on TMS320F2812 DSP and the toolbox Embedded Target for TI C2000 DSP in Matlab7.0, a design scheme of universal Ball Neodymium Magnets developing platform for motor control is proposed, which can greatly improve the developing efficiency of the motor control.
The platform is designed with TMS320F2812 as its core and realizes PWM signal trigger with EPM7128. The three-phase full-bridge circuit is constructed with IR2130. Moreover, by introducing the design method of DSP software based on the platform, a simple example for the application of the PWM module is given and the feasibility of the design scheme for platform software is verified.Considering the demands of the performance index for high precision speed source, by analyzing the principle, mathematical model and vector graphic of rare earth permanent magnetic synchronous motor (PMSM), the strategy of closed-loop control of power angle in VVVF of PMSM is proposed. In the system, the power angle is detected by HALL position sensor and the power angle closed-loop controller is designed with the method of PID fuzzy self-tuning. Thus the system not only http://www.chinamagnets.biz has a more rapid response speed, but also has smaller over-regulating and better static properties. In addition, the key technology included in the system is discussed in detail.The experiment shows that the high precision speed source has good speed precision and the demands of the performance index are reached. Under the power angle closed-loop control, the resistance capacity against load disturbance is improved and the problem of out-of-step is efficiently solved. In the steadily running mode, the operating current is remarkably decreased and the operating efficiency is increased. Moreover, the high precision speed source is successfully debugged in the platform, which verifies the correctness and the reliability of the platform.The platform which has both functions of teaching and product developing,
With the increasing demands for the motor control technology, common MCU can’t satisfy the control demands. However, the development of DSP technology can strongly support the implementation of advanced control theory and complex control algorithm. But in the development of motor control based on DSP, there are such many deficiencies as low efficiency and more needs for professional knowledge.Therefore, based on TMS320F2812 DSP and the toolbox Embedded Target for TI C2000 DSP in Matlab7.0, a design scheme of universal Ball Neodymium Magnets developing platform for motor control is proposed, which can greatly improve the developing efficiency of the motor control.
The platform is designed with TMS320F2812 as its core and realizes PWM signal trigger with EPM7128. The three-phase full-bridge circuit is constructed with IR2130. Moreover, by introducing the design method of DSP software based on the platform, a simple example for the application of the PWM module is given and the feasibility of the design scheme for platform software is verified.Considering the demands of the performance index for high precision speed source, by analyzing the principle, mathematical model and vector graphic of rare earth permanent magnetic synchronous motor (PMSM), the strategy of closed-loop control of power angle in VVVF of PMSM is proposed. In the system, the power angle is detected by HALL position sensor and the power angle closed-loop controller is designed with the method of PID fuzzy self-tuning. Thus the system not only http://www.chinamagnets.biz has a more rapid response speed, but also has smaller over-regulating and better static properties. In addition, the key technology included in the system is discussed in detail.The experiment shows that the high precision speed source has good speed precision and the demands of the performance index are reached. Under the power angle closed-loop control, the resistance capacity against load disturbance is improved and the problem of out-of-step is efficiently solved. In the steadily running mode, the operating current is remarkably decreased and the operating efficiency is increased. Moreover, the high precision speed source is successfully debugged in the platform, which verifies the correctness and the reliability of the platform.The platform which has both functions of teaching and product developing,
鱼雷推进用无传感器无刷直流电机动态性能分析
鱼雷推进用无传感器无刷直流电机动态性能分析
Due to high efficiency, excellent speed-adjustability, and high reliability, the high-power permanent-magnet brushless DC motor drive system has applied in the domains as ships, aircrafts and so on, where the attention is firstly paid to the running efficiency and feasibility of drive system.The dissertation proposes a speed-adjusting controller which applied to a large power capacity rare earth permanent magnet sensorless brushless DC motor (SLBLDCM). The dissertation strong magnets discusses the stepless speed-adjusting technic about torpedo drive motor, and the developing state of BLDCM .Considering the feature of the torpedo driver motor and the engineering application, the system scheme, the hardware and software of SLBLDCM are designed. Then, the operational principles of BLDCM and the PWM speed-adjusting theory are analyzed. Additional, the operational theory of the 2-phase feed up, all bridge star style 3-phase 6 states BLDCM system with 3 pair poles are analyzed. The mathematics model and the Stable state model of BLDCM system are abolished.Basing on key-technology issues which are faced in the course of BLDCM control system ①rotor position detection Basing on other approach to detect rotor position, we design a new approach to compensate larger scope http://www.chinamagnets.biz phase and a way to detect rotor position.②starting technique,basing on the very difficult examination problem when the EMF of SLBLDCM is lower,we proposed a starting technique, which is enhance the frequency and the voltage simultaneously .And this method has solved this problem well. ③torque ripple, we analyse the torque ripple due to the exchange phase and the effect of the pulse Width Modulation, and we suggested a new PWM modulates method (PWM-ON-PWM) .Through to calculation of torque ripple under this kind of pattern modulation We obtains this is one very good solution this question PWM modulation method. Based on the above research, hardware and software of a control subsystem are designed ,which use the TMS320LF2407.
Due to high efficiency, excellent speed-adjustability, and high reliability, the high-power permanent-magnet brushless DC motor drive system has applied in the domains as ships, aircrafts and so on, where the attention is firstly paid to the running efficiency and feasibility of drive system.The dissertation proposes a speed-adjusting controller which applied to a large power capacity rare earth permanent magnet sensorless brushless DC motor (SLBLDCM). The dissertation strong magnets discusses the stepless speed-adjusting technic about torpedo drive motor, and the developing state of BLDCM .Considering the feature of the torpedo driver motor and the engineering application, the system scheme, the hardware and software of SLBLDCM are designed. Then, the operational principles of BLDCM and the PWM speed-adjusting theory are analyzed. Additional, the operational theory of the 2-phase feed up, all bridge star style 3-phase 6 states BLDCM system with 3 pair poles are analyzed. The mathematics model and the Stable state model of BLDCM system are abolished.Basing on key-technology issues which are faced in the course of BLDCM control system ①rotor position detection Basing on other approach to detect rotor position, we design a new approach to compensate larger scope http://www.chinamagnets.biz phase and a way to detect rotor position.②starting technique,basing on the very difficult examination problem when the EMF of SLBLDCM is lower,we proposed a starting technique, which is enhance the frequency and the voltage simultaneously .And this method has solved this problem well. ③torque ripple, we analyse the torque ripple due to the exchange phase and the effect of the pulse Width Modulation, and we suggested a new PWM modulates method (PWM-ON-PWM) .Through to calculation of torque ripple under this kind of pattern modulation We obtains this is one very good solution this question PWM modulation method. Based on the above research, hardware and software of a control subsystem are designed ,which use the TMS320LF2407.
无刷直流鱼雷推进电机控制器设计
无刷直流鱼雷推进电机控制器设计
The thesis discusses the state-of-the-art of BLDCM and the pending further study of the main issue. The thesis discusses the key-technology about a control system project which applied to a large power capacity rare earth permanent magnet brushless DC motor (BLDCM), designs the hardware and software of the BLDCM control system.The thesis analyzes the causes of the torque ripple BLDCM and the commutation current. Building the BLDCM model under the conditions of the magnetic circuit which is not saturated, eddy current and hysteresis loss which is neodymium rare earth magnets not consider, the three-phase windings of the brushless DC motor which is completely symmetrical. Compare with the torque in non-commutation interval, analyzing the torque formula in different current slopes. Derivation different torque ripple in different current slopes. Combining the formula was derived and references, then bringing up the method which is based on the hysteresis current law to restrain torque ripple. Next, the method of regulating the speed of BLDCM is studied detailedly. On the basis of fuzzy control, Fuzzy controller regulate the speed with hysteresis current regulator bicyclic current http://www.chinamagnets.biz regulation governing system PID controller and with the use of speed adjustment current hysteresis current regulator with the adjustment bicyclic systems in MATLAB simulation speed, proved its superiority in less torque ripple and less speed change; On the basis of the above, TMS320LF2407A control subsystem based on the complete hardware design: The clock module, memory modules, etc. According to the hardware design, the main program flow, speed adjustment, the current regulation, and commutation logic are completely designed by DSP.
The thesis discusses the state-of-the-art of BLDCM and the pending further study of the main issue. The thesis discusses the key-technology about a control system project which applied to a large power capacity rare earth permanent magnet brushless DC motor (BLDCM), designs the hardware and software of the BLDCM control system.The thesis analyzes the causes of the torque ripple BLDCM and the commutation current. Building the BLDCM model under the conditions of the magnetic circuit which is not saturated, eddy current and hysteresis loss which is neodymium rare earth magnets not consider, the three-phase windings of the brushless DC motor which is completely symmetrical. Compare with the torque in non-commutation interval, analyzing the torque formula in different current slopes. Derivation different torque ripple in different current slopes. Combining the formula was derived and references, then bringing up the method which is based on the hysteresis current law to restrain torque ripple. Next, the method of regulating the speed of BLDCM is studied detailedly. On the basis of fuzzy control, Fuzzy controller regulate the speed with hysteresis current regulator bicyclic current http://www.chinamagnets.biz regulation governing system PID controller and with the use of speed adjustment current hysteresis current regulator with the adjustment bicyclic systems in MATLAB simulation speed, proved its superiority in less torque ripple and less speed change; On the basis of the above, TMS320LF2407A control subsystem based on the complete hardware design: The clock module, memory modules, etc. According to the hardware design, the main program flow, speed adjustment, the current regulation, and commutation logic are completely designed by DSP.
基于ARM的变温空调伺服系统设计
基于ARM的变温空调伺服系统设计
Temperature-adjusted air-conditioner is a temperature followed system which is based on "indoor microclimate" principle in medical aerography. Compared with traditional air-conditioner, it does not preset value for indoor environment, but intelligently controls indoor temperature according to outdoor temperature variety. Temperature-adjusted air-conditioner emploies semiconductor refrigerator as cold (hot) source, Brushless Direct-Current (BLDC) motor as execute outfit, it realizes the rapid follow and adjusts indoor temperature with outdoor temperature.Temperature servo rare earth magnets system used as execute outfit is a subsystem of temperature-adjusted air-conditioner. Based on the principle of temperature-adjusted air-conditioner, a kind of digital servo control system with ARM (Advanced RISC Machines) microchip LPC2214 as its core is presented.
The whole structure and control scheme of the system, realization methods for all parts have been analyzed in detail, then, the feasibility of design is demonstrated, and hardware circuit is designed. The hardware circuit of temperature servo system uses digital temperature controller with LPC2214 as its core, the system samples indoor and outdoor temperature signals with temperature sensor DS1820, and displays all kinds of parameters with LCD module.Aimed at BLDC motor, which is the execute outfits of temperature servo system, a kind of power driven circuit http://www.chinamagnets.biz which uses power MOSFET and gate driven integrate circuit IR2130 is designed for servo system. The BLDC motor can be driven effectively by selecting bootstrap components reasonably and protecting power component correctly.On the basis of characteristic of temperature servo control system, a kind of control arithmetic based on tri-loop model with indoor temperature, rotate speed and current has been presented. The speed-adjusted program of temperature servo control system has been written with C language, compiled, linked and run in ADS (ARM Developer Suite) environment successfully.The BLDC motor di-loop model has been established in MATLAB environment, and the PED parameters of speed loop and current loop are fixed on with Ziegler-Nichols method, which provides reference for actual design.
Temperature-adjusted air-conditioner is a temperature followed system which is based on "indoor microclimate" principle in medical aerography. Compared with traditional air-conditioner, it does not preset value for indoor environment, but intelligently controls indoor temperature according to outdoor temperature variety. Temperature-adjusted air-conditioner emploies semiconductor refrigerator as cold (hot) source, Brushless Direct-Current (BLDC) motor as execute outfit, it realizes the rapid follow and adjusts indoor temperature with outdoor temperature.Temperature servo rare earth magnets system used as execute outfit is a subsystem of temperature-adjusted air-conditioner. Based on the principle of temperature-adjusted air-conditioner, a kind of digital servo control system with ARM (Advanced RISC Machines) microchip LPC2214 as its core is presented.
The whole structure and control scheme of the system, realization methods for all parts have been analyzed in detail, then, the feasibility of design is demonstrated, and hardware circuit is designed. The hardware circuit of temperature servo system uses digital temperature controller with LPC2214 as its core, the system samples indoor and outdoor temperature signals with temperature sensor DS1820, and displays all kinds of parameters with LCD module.Aimed at BLDC motor, which is the execute outfits of temperature servo system, a kind of power driven circuit http://www.chinamagnets.biz which uses power MOSFET and gate driven integrate circuit IR2130 is designed for servo system. The BLDC motor can be driven effectively by selecting bootstrap components reasonably and protecting power component correctly.On the basis of characteristic of temperature servo control system, a kind of control arithmetic based on tri-loop model with indoor temperature, rotate speed and current has been presented. The speed-adjusted program of temperature servo control system has been written with C language, compiled, linked and run in ADS (ARM Developer Suite) environment successfully.The BLDC motor di-loop model has been established in MATLAB environment, and the PED parameters of speed loop and current loop are fixed on with Ziegler-Nichols method, which provides reference for actual design.
2012年8月15日星期三
Research on Dynamic Model and Simulations of Erbium-Doped Fiber Lasers
Research on Dynamic Model and Simulations of Erbium-Doped Fiber Lasers
With the rapid development and applications of rare-earth doped fiber and the DWDM technology in optical fiber communications, Optical Fiber Lasers with various novel structures became a hot and key research field in optoelectronic devices. Due to the advantages of matching with the optical fiber systems, potential narrow width, high output power, and wavelength tunability, optical fiber lasers would find more and more application in future high-speed and long-haul fiber DWDM communication systems.In this thesis, the status and progresses of fiber laser are introduced Block Neodymium magnets and the configuration and principle of existing EDFLs were analyzed and discussed, based on this, Erbium-doped fiber lasers based on Hi-Bi fiber Sagnac Loops were deeply studied in details.
The major works and results obtained are as following:1. Mainly focus on and discuss the properties of Erbium-doped fiber, the energy level diagram generated by Er 3+ and pump light were demonstrated, the contribution of pump in different wavelength were also analyzed.2. As the researched Erbium-doped fiber laser used Hi-Bi fiber Sagnac loop as the feedback device, the theory of the optical characteristics were demonstrated in detail; the result provided by simulation were carefully discussed and analyzed. In order to better analyze the influence, different values of the parameter in polarization controller, Hi-Bi fiber and coupler were used in the simulation and results has been studied.3. We analyzed the theory of the rate equation, the gain threshold resonance condition and http://www.999magnet.com angle resonance condition of the fiber laser, other key performance parameters were also discussed, e.g. the absorption and emission spectra of the Erbium-doped fiber, the life-time of optics in the resonant, etc. 4. Based on the above theory analysis, a dynamic model of Erbium-doped fiber laser based on Hi-Bi fiber Sagnac Loop were established, numerical methods are used to analyze the graph of particle concentration and output laser power per time, and to calculate both the reflection spectra and laser power spectra.5. In the last part of the thesis, we discussed the further potential research based on the current job we’ve accomplished as well as the research and development trends in future for the EDFL in optical fiber communication system.
With the rapid development and applications of rare-earth doped fiber and the DWDM technology in optical fiber communications, Optical Fiber Lasers with various novel structures became a hot and key research field in optoelectronic devices. Due to the advantages of matching with the optical fiber systems, potential narrow width, high output power, and wavelength tunability, optical fiber lasers would find more and more application in future high-speed and long-haul fiber DWDM communication systems.In this thesis, the status and progresses of fiber laser are introduced Block Neodymium magnets and the configuration and principle of existing EDFLs were analyzed and discussed, based on this, Erbium-doped fiber lasers based on Hi-Bi fiber Sagnac Loops were deeply studied in details.
The major works and results obtained are as following:1. Mainly focus on and discuss the properties of Erbium-doped fiber, the energy level diagram generated by Er 3+ and pump light were demonstrated, the contribution of pump in different wavelength were also analyzed.2. As the researched Erbium-doped fiber laser used Hi-Bi fiber Sagnac loop as the feedback device, the theory of the optical characteristics were demonstrated in detail; the result provided by simulation were carefully discussed and analyzed. In order to better analyze the influence, different values of the parameter in polarization controller, Hi-Bi fiber and coupler were used in the simulation and results has been studied.3. We analyzed the theory of the rate equation, the gain threshold resonance condition and http://www.999magnet.com angle resonance condition of the fiber laser, other key performance parameters were also discussed, e.g. the absorption and emission spectra of the Erbium-doped fiber, the life-time of optics in the resonant, etc. 4. Based on the above theory analysis, a dynamic model of Erbium-doped fiber laser based on Hi-Bi fiber Sagnac Loop were established, numerical methods are used to analyze the graph of particle concentration and output laser power per time, and to calculate both the reflection spectra and laser power spectra.5. In the last part of the thesis, we discussed the further potential research based on the current job we’ve accomplished as well as the research and development trends in future for the EDFL in optical fiber communication system.
The Research of the Influences of Metal Ions’Doping on the Photocatalytic Property of Nano-Sized TiO2 Thin Films
The Research of the Influences of Metal Ions’Doping on the Photocatalytic Property of Nano-Sized TiO2 Thin Films
In this paper, TiO2 thin films doped by different metal ions were prepared on the microscope slides and ceramic tiles by Sol-gel method. Meanwhile, the photocatalytic property of TiO2 thin films influenced by doped metal ions were researched.The microstructure, surface morphology and crystal particle sizes of TiO2 thin films were investigated by AFM and XRD. Besides, the light-absorbing property of the films were analyzed by Ultraviolet-Visible Spectrophotometer. The influences of annealing temperature and thickness of the films on the photocatalytic property of TiO2 films Segment neodymium magnets were also discussed. Moreover,we mainly researched on the influences of different doped metal ions on the photocatalytic property of TiO2 films by degradating heavy oil, water solutions of Rhodamine B, Methyl orange and Mthylene blue. Then the influences of mutual effects between the carriers and the films on the photocatalytic property of TiO2 films were discussed. The following results were obtained:(1) The TiO2 films were rough and continuous,the crystal particles were even . (2) The TiO2 thin films had little absorption during the visible light spectrum while absorbed almost all lights during the ultraviolet light spectrum; For the TiO2 films doped by the transition metal ions, the blue migration extent increased with the increase of ionic radius, and for the TiO2 films doped by the lanthanon ions,the red migration http://www.999magnet.com extent increased with the decrease of ionic radius.(3) The preparing parameters for TiO2 thin films with maximum degradation efficiency for dye solution and best photocatalytic property were 4-layer thickness, annealing at 500℃ for 2 hours.
In this paper, TiO2 thin films doped by different metal ions were prepared on the microscope slides and ceramic tiles by Sol-gel method. Meanwhile, the photocatalytic property of TiO2 thin films influenced by doped metal ions were researched.The microstructure, surface morphology and crystal particle sizes of TiO2 thin films were investigated by AFM and XRD. Besides, the light-absorbing property of the films were analyzed by Ultraviolet-Visible Spectrophotometer. The influences of annealing temperature and thickness of the films on the photocatalytic property of TiO2 films Segment neodymium magnets were also discussed. Moreover,we mainly researched on the influences of different doped metal ions on the photocatalytic property of TiO2 films by degradating heavy oil, water solutions of Rhodamine B, Methyl orange and Mthylene blue. Then the influences of mutual effects between the carriers and the films on the photocatalytic property of TiO2 films were discussed. The following results were obtained:(1) The TiO2 films were rough and continuous,the crystal particles were even . (2) The TiO2 thin films had little absorption during the visible light spectrum while absorbed almost all lights during the ultraviolet light spectrum; For the TiO2 films doped by the transition metal ions, the blue migration extent increased with the increase of ionic radius, and for the TiO2 films doped by the lanthanon ions,the red migration http://www.999magnet.com extent increased with the decrease of ionic radius.(3) The preparing parameters for TiO2 thin films with maximum degradation efficiency for dye solution and best photocatalytic property were 4-layer thickness, annealing at 500℃ for 2 hours.
The Effect of Y、Ce、Sr Addition on the Microstructures and Mechanical Properties of Magnesium Alloys
The Effect of Y、Ce、Sr Addition on the Microstructures and Mechanical Properties of Magnesium Alloys
Magnesium alloys offer good combination of mechanical properties, high specific strength and stiffness, superior damping capacity, high thermal conductivity, high dimensional stability, good electromagnetic shielding characteristics and good machinability. The attractive mechanical properties of magnesium and its alloys increase their use for many technical applications, i.e. automobile, aeronautical and aerospace, housing utensils and electronic industries, etc. However, commercial applications of magnesium alloys are limited because of poor creep resistance and poor tensile properties at elevated temperature above 120℃. AZ91D is the widely used Mg-Al alloys in the Alnico magnets industry apply at present, offering a good combination of mechanical properties at ambient temperature, die castability and corrosion resistance. But the worse creep strength restricted its further used. The researcher studied the alloys, heat treatment, squeezing and fast solidifying on the microstructure and mechanical properties of AZ91D magnesium alloys. This experiment mainly study the alloys element on the microstructure and mechanical properties of magnesium alloys through addition Sr and RE (Y and Ce ).The results show that the microstructure of AZ91D alloys were significant refined with Y, Ce and Sr additions. The refinement degree increased with the addition content of alloy element increasing and had needle-shaped Al11Ce3, Al4Sr phase and block Al2Y phase generated. The optimum refinement degree can http://www.999magnet.com obtained, it decreased about 40.2%, 41.6% and 50% compared to the original size. But the microstructure was not refined with the addition content further additions. The microstructure also can be significant refined when the Y、Ce、Sr were composite additions. The vary tendency same to single element addition. The minimum grain size can obtained which decreased about 48.1%、60% and 55.6% compared with initial microstructure size.The spacing interval reducing ofα-Mg dendrites when adding the Y element to
Magnesium alloys offer good combination of mechanical properties, high specific strength and stiffness, superior damping capacity, high thermal conductivity, high dimensional stability, good electromagnetic shielding characteristics and good machinability. The attractive mechanical properties of magnesium and its alloys increase their use for many technical applications, i.e. automobile, aeronautical and aerospace, housing utensils and electronic industries, etc. However, commercial applications of magnesium alloys are limited because of poor creep resistance and poor tensile properties at elevated temperature above 120℃. AZ91D is the widely used Mg-Al alloys in the Alnico magnets industry apply at present, offering a good combination of mechanical properties at ambient temperature, die castability and corrosion resistance. But the worse creep strength restricted its further used. The researcher studied the alloys, heat treatment, squeezing and fast solidifying on the microstructure and mechanical properties of AZ91D magnesium alloys. This experiment mainly study the alloys element on the microstructure and mechanical properties of magnesium alloys through addition Sr and RE (Y and Ce ).The results show that the microstructure of AZ91D alloys were significant refined with Y, Ce and Sr additions. The refinement degree increased with the addition content of alloy element increasing and had needle-shaped Al11Ce3, Al4Sr phase and block Al2Y phase generated. The optimum refinement degree can http://www.999magnet.com obtained, it decreased about 40.2%, 41.6% and 50% compared to the original size. But the microstructure was not refined with the addition content further additions. The microstructure also can be significant refined when the Y、Ce、Sr were composite additions. The vary tendency same to single element addition. The minimum grain size can obtained which decreased about 48.1%、60% and 55.6% compared with initial microstructure size.The spacing interval reducing ofα-Mg dendrites when adding the Y element to
Effect of Ce on Solidification and Rolling Deformation of AZ31
Effect of Ce on Solidification and Rolling Deformation of AZ31
Magnesium alloys are widely used in automobile, electric and aerospace industries due to its combination of light-weight and high specific strength. At room-temperature, Magnesium alloy is hard to plastically deform because Magnesium crystal shows close-packed hexagonal structure. So it is necessary to research its influence factors of high-temperature deformation in order to enhance its plastic deformation capability.This article selects casting and rolling as study objects. Variant contents of Ce respectively are added into AZ31 to cast AZ31Ce serial alloys. This article studies effect of Ce on solidification and microstructure, deformation capacities of Alnico magnets as-cast AZ31, mechanics property and fracture behavior of rolled AZ31.The following are main studying content:Different content of Ce are added into AZ31 which are used to analyze effect of Ce on crystal growing in liquid AZ31;Using extremal rolling experiment to test max. total reduction and max. pass reduction of as-cast AZ31 so that we can tell which plastic deformation ability is best;Room-temperature tensile test is applied on rolled AZ31 to research influence of Ce on mechanics property and fracture behavior of rolled AZ31.After research above, I reach conclusions as fellow:As-cast AZ31 without Ce is composed ofα-Mg andβ-Mg17Al12. When Ce content is 0.2 percent,α-Mg dose not obviously change, while http://www.999magnet.com net-shapedβ-Mg17Al12 begins to break into massive. When Ce content rises to 0.6 percent,α-Mg crystal refines obviously andβ-Mg17Al12 totally appears as massive. In addition, little rod-shaped Al4Ce appears on crystal boundary. When Ce content reaches 0.8 percent,α-Mg further refines,β-Mg17Al12 also refines and decreases, more and bigger Al4Ce appears.Big degree of undercooling caused by solute segregation at interface of solid
Magnesium alloys are widely used in automobile, electric and aerospace industries due to its combination of light-weight and high specific strength. At room-temperature, Magnesium alloy is hard to plastically deform because Magnesium crystal shows close-packed hexagonal structure. So it is necessary to research its influence factors of high-temperature deformation in order to enhance its plastic deformation capability.This article selects casting and rolling as study objects. Variant contents of Ce respectively are added into AZ31 to cast AZ31Ce serial alloys. This article studies effect of Ce on solidification and microstructure, deformation capacities of Alnico magnets as-cast AZ31, mechanics property and fracture behavior of rolled AZ31.The following are main studying content:Different content of Ce are added into AZ31 which are used to analyze effect of Ce on crystal growing in liquid AZ31;Using extremal rolling experiment to test max. total reduction and max. pass reduction of as-cast AZ31 so that we can tell which plastic deformation ability is best;Room-temperature tensile test is applied on rolled AZ31 to research influence of Ce on mechanics property and fracture behavior of rolled AZ31.After research above, I reach conclusions as fellow:As-cast AZ31 without Ce is composed ofα-Mg andβ-Mg17Al12. When Ce content is 0.2 percent,α-Mg dose not obviously change, while http://www.999magnet.com net-shapedβ-Mg17Al12 begins to break into massive. When Ce content rises to 0.6 percent,α-Mg crystal refines obviously andβ-Mg17Al12 totally appears as massive. In addition, little rod-shaped Al4Ce appears on crystal boundary. When Ce content reaches 0.8 percent,α-Mg further refines,β-Mg17Al12 also refines and decreases, more and bigger Al4Ce appears.Big degree of undercooling caused by solute segregation at interface of solid
Study on the Processes of Soil Erosion Using REE Tracers on Sloping Land and the Effect on Reducing Sediment of Different Underlying Surfaces
Study on the Processes of Soil Erosion Using REE Tracers on Sloping Land and the Effect on Reducing Sediment of Different Underlying Surfaces
It is erosion development and mechanism that is always the key to the study of soil erosion, which directly influenced establishment and development of soil erosion physical model. There are lots of problems in quantitative identification of soil erosion process owing to limits of research methods presently. With rainfall of outdoors and technology of instrument neutron activation analysis (INAA), we conducted a laboratory and outdoor experiment in which different sections of steep slope of 22o and different depths of profile were tagged with different rear earth Magnetic lifter elements (REE.) to quantify cationally soil erosion processes and deposition of one rainfall event and consecutive rainfall event on slope land, aiming at supplying new data and method for establishing soil erosion physical model in the Loess Plateau.
Moreover, according to the ecological environment control as well as quick vegetation recovery in short time, large scale and high velocity in watershed on the Loess Plateau,the paper studied the effects of different vegetation on runoff and sediment production in plots with small scale, and the rules of runoff and sediment production on different slope types adopting the monitoring on the dynamic progress of runoff and sediment on slope in erosion plots of different underlying surfaces, which will give scientific basis for quantified evaluation on the soil and water conservation efficiency of biological practices as well as the post-evaluation of national policy of pasture and forest land reclamation.1. Discussing the relativity between amount of runoff, sediment production and soil erosionThe http://www.999magnet.com amount of runoff corresponded well with soil erosion, and their correlation coefficient was 0.84～0.94 in outdoor rainfall. However, there was weak correlation between the amount of runoff and sediment production.The amount of runoff, sediment concentration, amount of soil erosion on the plot was increasing with the time of rainfall continue. The increasing amount of the accumulated erosion on the plot was small at initial stage of rainfall, and significantly increased with rainfall time, it have a proliferate point .2. Making a analysis on the processes from sheet erosion to rill erosion
It is erosion development and mechanism that is always the key to the study of soil erosion, which directly influenced establishment and development of soil erosion physical model. There are lots of problems in quantitative identification of soil erosion process owing to limits of research methods presently. With rainfall of outdoors and technology of instrument neutron activation analysis (INAA), we conducted a laboratory and outdoor experiment in which different sections of steep slope of 22o and different depths of profile were tagged with different rear earth Magnetic lifter elements (REE.) to quantify cationally soil erosion processes and deposition of one rainfall event and consecutive rainfall event on slope land, aiming at supplying new data and method for establishing soil erosion physical model in the Loess Plateau.
Moreover, according to the ecological environment control as well as quick vegetation recovery in short time, large scale and high velocity in watershed on the Loess Plateau,the paper studied the effects of different vegetation on runoff and sediment production in plots with small scale, and the rules of runoff and sediment production on different slope types adopting the monitoring on the dynamic progress of runoff and sediment on slope in erosion plots of different underlying surfaces, which will give scientific basis for quantified evaluation on the soil and water conservation efficiency of biological practices as well as the post-evaluation of national policy of pasture and forest land reclamation.1. Discussing the relativity between amount of runoff, sediment production and soil erosionThe http://www.999magnet.com amount of runoff corresponded well with soil erosion, and their correlation coefficient was 0.84～0.94 in outdoor rainfall. However, there was weak correlation between the amount of runoff and sediment production.The amount of runoff, sediment concentration, amount of soil erosion on the plot was increasing with the time of rainfall continue. The increasing amount of the accumulated erosion on the plot was small at initial stage of rainfall, and significantly increased with rainfall time, it have a proliferate point .2. Making a analysis on the processes from sheet erosion to rill erosion
2012年8月13日星期一
The Synthesis and Characterization of NASICON-type Mineral Solid State Electrolytes
The Synthesis and Characterization of NASICON-type Mineral Solid State Electrolytes
This thesis includes two parts. Part one gives some backgrounds about this thesis. In this part, the crystal structure and conduction mechanism of NASICON are reviewed. An introduction on the developments for the NASICON-type sold state electrolytes is also gives. Part two deals with the synthesis and characterization of NaTi2(PO4)3-based、LiTi2(PO4)3-based and NaSn2(PO4)3-based mineral sold state electrolytes prepared by high temperature Special shape NdFeB magnets solid state reaction using refined nature pyrophyllite and rare earths oxides as starting materials.
The compositions have been characterized by XRD、IR and A.C. impedance technique. Four systems of mineral sold state electrolytes are studied, they are Na1+3x+yAlxNdyTi2-x-ySi2xP3-2xO12、Na1+3x+yAlxYyTi2-x-ySi2xP3-2xO12、Li1+3x+yAlxLayTi2-x-ySi2xP3-2xO12 and Na1+3xAlxSn2-xSi2xP3-2xO12. For Na1+3x+yAlxNdyTi2-x-ySi2xP3-2xO12, A.C. impedance measurements indicate that the initial composition with y=0.3, x=0.1 possesses maximum ionic conductivity with 1.80×10-2S/cm at 623K, its activation energy is 38.2 KJ/mol in the temperature range of 473-623K. X-ray powder diffraction analysis shows that a NASICON-type phase exists in the composition range of y=0.3, x ≤ 0.3 and y=0.5, x ≤ 0.2. For Na1+3x+yAlxYyTi2-x-ySi2xP3-2xO12, the initial composition with x=0.1, y=0.3 possesses high ionic conductivity with 1×10-2S/cm at 673K, its activation energy is 55.5 KJ/mol in the temperature range of 473-623K. For Li1+3x+yAlxLayTi2-x-ySi2xP3-2xO12 systems, the initial composition with x=0.1, y=0.4 has the best ionic conductivity http://www.999magnet.com with 4.20×10-5S/cm at room temperature , 8.31×10-3S/cm at 673K, its activation energy is19.9KJ/mol in the temperature range of 523-673K. For Na1+3xAlxSn2-xSi2xP3-2xO12, a NaSn2(PO4)3-type solid solution phase with R 3 space group exists in the composition range of x≤0.4, the initial composition with x=0.4 has the best ionic conductivity with 6.91×10-3S/cm at 623K,its activation energy is 50.7KJ/mol in the temperature range of 473-623K. IR spectra analysis shows that most products of the above four systems are stable to water. The previous results indicate that four systems are good sold state electrolytes and it is practical to reformed natural mineral into sold state electrolytes.
This thesis includes two parts. Part one gives some backgrounds about this thesis. In this part, the crystal structure and conduction mechanism of NASICON are reviewed. An introduction on the developments for the NASICON-type sold state electrolytes is also gives. Part two deals with the synthesis and characterization of NaTi2(PO4)3-based、LiTi2(PO4)3-based and NaSn2(PO4)3-based mineral sold state electrolytes prepared by high temperature Special shape NdFeB magnets solid state reaction using refined nature pyrophyllite and rare earths oxides as starting materials.
The compositions have been characterized by XRD、IR and A.C. impedance technique. Four systems of mineral sold state electrolytes are studied, they are Na1+3x+yAlxNdyTi2-x-ySi2xP3-2xO12、Na1+3x+yAlxYyTi2-x-ySi2xP3-2xO12、Li1+3x+yAlxLayTi2-x-ySi2xP3-2xO12 and Na1+3xAlxSn2-xSi2xP3-2xO12. For Na1+3x+yAlxNdyTi2-x-ySi2xP3-2xO12, A.C. impedance measurements indicate that the initial composition with y=0.3, x=0.1 possesses maximum ionic conductivity with 1.80×10-2S/cm at 623K, its activation energy is 38.2 KJ/mol in the temperature range of 473-623K. X-ray powder diffraction analysis shows that a NASICON-type phase exists in the composition range of y=0.3, x ≤ 0.3 and y=0.5, x ≤ 0.2. For Na1+3x+yAlxYyTi2-x-ySi2xP3-2xO12, the initial composition with x=0.1, y=0.3 possesses high ionic conductivity with 1×10-2S/cm at 673K, its activation energy is 55.5 KJ/mol in the temperature range of 473-623K. For Li1+3x+yAlxLayTi2-x-ySi2xP3-2xO12 systems, the initial composition with x=0.1, y=0.4 has the best ionic conductivity http://www.999magnet.com with 4.20×10-5S/cm at room temperature , 8.31×10-3S/cm at 673K, its activation energy is19.9KJ/mol in the temperature range of 523-673K. For Na1+3xAlxSn2-xSi2xP3-2xO12, a NaSn2(PO4)3-type solid solution phase with R 3 space group exists in the composition range of x≤0.4, the initial composition with x=0.4 has the best ionic conductivity with 6.91×10-3S/cm at 623K,its activation energy is 50.7KJ/mol in the temperature range of 473-623K. IR spectra analysis shows that most products of the above four systems are stable to water. The previous results indicate that four systems are good sold state electrolytes and it is practical to reformed natural mineral into sold state electrolytes.
The Microstructure and Properties Study of Ni-Al-graphite Self-lubricating Material
The Microstructure and Properties Study of Ni-Al-graphite Self-lubricating Material
Self-lubricating composite which possesses superior antifriction and wear resistance has been one of the central issues for advanced material research. Ni-Al-graphite alloy was produced by vacuum induction melting, and the effect of Al content on microstructure and properties of the composite were studied. The results show: the addition of Al component into the Ni-graphite alloy indicates that Al element is not only an element that strengthens the alloy matrix, but also nodularizer that promotes the transition from flaky graphite to spheroidal graphite. It reveals that the carbon atoms mainly exist in graphitic form in Ni-Al-C ternary alloy. The alloy with 4.25 mass percent Al content possesses high content of graphite with the main morphology of eutectic graphite and the matrix Special shape NdFeB magnets
of the alloy is γ-Ni(Al) solution single. With the increment of Al content, under less and primary graphite there has a tendency of spherical transformation. γ-Ni(Al) solution and a small quantity of (γ+γ′)E binary eutectic make up the matrix of the alloy with 6.85 mass percent Al content. As the Al content is in the range of 8.13-9.94 mass percent, γ-Ni(Al) solution disappears, the solidifying structure of the alloy is composed of pro-eutectic γ′-Ni3Al(,γ+γ′)E and graphite. The matrix is γ′-Ni3Al and Ni3AlC0.5 phase with high hardness is observed on reticular intergranular in the alloy of 12.74 mass percent Al content. The effects of Al content on the physics, mechanical and tribological properties were investigated.
The results show that the small thermal expansion coefficient of Ni-Al-graphite alloy makes it qualify for engine and piston ring material, and the impact toughness reaches about 2~17-fold compare to Ni-Ag-C prepared by PM method. With the increasing of Al content, the density and impact toughness decrease while the hardness increases. The transformation of thermal expansion coefficient presents nearly “N” shape with the increment of Al content. And the tensile strength and bend strength increase at first and reduce then. The extrusion and swearing course of graphite in surface & inferior surface is the formation dynamic force of dry-tribolayer. During the course of wear, the http://www.999magnet.com superficial friction film of Ni-Al-graphite composite follows the law of formation, service, delamination and regeneration. The dry friction coefficient and wear rate reduce at first and increase then with the increasing of Al content. Under the oil lubricating condition, the solid-fluid (graphite-oil) lubricant film is the basic reason why tribological performance of the composite can remarkably improved. With the increment of Al content, the wear rate reduces while the friction coefficient rises at first and descends then. The addition of RE-Mg nodularizer plays an effective spheroidized role to the graphite in the alloy, remarkably improves the impact toughness and dry friction properties of the composite. The spheroidal mechanism of graphite in Ni-Al-graphite alloy lies in: Al reacts with O in the liquid metal, which leads to the purification of liquid metal and the increasing of undercooling during solidification.
Self-lubricating composite which possesses superior antifriction and wear resistance has been one of the central issues for advanced material research. Ni-Al-graphite alloy was produced by vacuum induction melting, and the effect of Al content on microstructure and properties of the composite were studied. The results show: the addition of Al component into the Ni-graphite alloy indicates that Al element is not only an element that strengthens the alloy matrix, but also nodularizer that promotes the transition from flaky graphite to spheroidal graphite. It reveals that the carbon atoms mainly exist in graphitic form in Ni-Al-C ternary alloy. The alloy with 4.25 mass percent Al content possesses high content of graphite with the main morphology of eutectic graphite and the matrix Special shape NdFeB magnets
of the alloy is γ-Ni(Al) solution single. With the increment of Al content, under less and primary graphite there has a tendency of spherical transformation. γ-Ni(Al) solution and a small quantity of (γ+γ′)E binary eutectic make up the matrix of the alloy with 6.85 mass percent Al content. As the Al content is in the range of 8.13-9.94 mass percent, γ-Ni(Al) solution disappears, the solidifying structure of the alloy is composed of pro-eutectic γ′-Ni3Al(,γ+γ′)E and graphite. The matrix is γ′-Ni3Al and Ni3AlC0.5 phase with high hardness is observed on reticular intergranular in the alloy of 12.74 mass percent Al content. The effects of Al content on the physics, mechanical and tribological properties were investigated.
The results show that the small thermal expansion coefficient of Ni-Al-graphite alloy makes it qualify for engine and piston ring material, and the impact toughness reaches about 2~17-fold compare to Ni-Ag-C prepared by PM method. With the increasing of Al content, the density and impact toughness decrease while the hardness increases. The transformation of thermal expansion coefficient presents nearly “N” shape with the increment of Al content. And the tensile strength and bend strength increase at first and reduce then. The extrusion and swearing course of graphite in surface & inferior surface is the formation dynamic force of dry-tribolayer. During the course of wear, the http://www.999magnet.com superficial friction film of Ni-Al-graphite composite follows the law of formation, service, delamination and regeneration. The dry friction coefficient and wear rate reduce at first and increase then with the increasing of Al content. Under the oil lubricating condition, the solid-fluid (graphite-oil) lubricant film is the basic reason why tribological performance of the composite can remarkably improved. With the increment of Al content, the wear rate reduces while the friction coefficient rises at first and descends then. The addition of RE-Mg nodularizer plays an effective spheroidized role to the graphite in the alloy, remarkably improves the impact toughness and dry friction properties of the composite. The spheroidal mechanism of graphite in Ni-Al-graphite alloy lies in: Al reacts with O in the liquid metal, which leads to the purification of liquid metal and the increasing of undercooling during solidification.
2012年8月7日星期二
Preparation and Demage Mechanism at High Temperature of RMO/(Si3N4+BN) Composites
Preparation and Demage Mechanism at High Temperature of RMO/(Si3N4+BN) Composites
RMO/(Si3N4+BN) composites were synthesized by hot-pressing at 1800℃for 1 hour under a pressure of 20 MPa in a 0.1 MPa nitrogen atmosphere. Analyzed the microstructure and the component using analytical methods such as XRD, SEM, TEM. Tested the room-temperature mechanical properties of the RMO/(Si3N4+BN) composites. Research both the thermal shock resistance and the oxidation resistance.Compound rare-earth oxides RMO Segment neodymium magnet made a contribution of the density of the RMO/(Si3N4+BN) composites during the hot-pressing sintering course. The composites show wonderful general mechanical properties due to the in-situ grownβ-Si3N4 whisker.
The flexural strength of composite of 50% Si3N4 and 20% BN can approach 487.7 MPa, the fracture toughness reached 7.8MPa/m1/2. even the composite of 50% BN and 20% Si3N4 component can reach 200.5 MPa.The research results show that RMO/(Si3N4+BN) composites have excellent thermal shock resistance. The residual strength was bigger than the original values after once water quenching at the thermal shock temperature of 800℃, 1000℃and 1200℃. There are two reasons of this phenomenon, one is that the thermophysical properties of the composites were excellent; the other is the formation of a dense oxidation layer on the surface of the composites at high temperature, and the oxidation layer smoothed the surface and healed the micro-crack on the surface.The http://www.chinamagnets.biz results of thermal shock resistance calculation show that by optioning the composion, the composite show the superior thermal shock resistance. For instance, the first ,the second and the third thermal stress resistant factor of the composite (40Vol%BN,40Vol%Si3N4) approached 870929℃, 76478166 J·m-1·s-1 and 3.894.15×10-3m2·K·s-1. the composite can be used at a circumstance of 9861052℃temperature difference, the highest cooling velocity can be 51865538 K·s-1.The results of the oxidation experiment at the high temperature of the RMO/(Si3N4+BN) composites, show that a weight losses during oxidation because of the oxide of BN. A uniform silicate film was found at the surface of the composites. The formation of silicate films decline the velocity of the oxidation and resulting in the composites fairly good high temperature oxidation resistance.
RMO/(Si3N4+BN) composites were synthesized by hot-pressing at 1800℃for 1 hour under a pressure of 20 MPa in a 0.1 MPa nitrogen atmosphere. Analyzed the microstructure and the component using analytical methods such as XRD, SEM, TEM. Tested the room-temperature mechanical properties of the RMO/(Si3N4+BN) composites. Research both the thermal shock resistance and the oxidation resistance.Compound rare-earth oxides RMO Segment neodymium magnet made a contribution of the density of the RMO/(Si3N4+BN) composites during the hot-pressing sintering course. The composites show wonderful general mechanical properties due to the in-situ grownβ-Si3N4 whisker.
The flexural strength of composite of 50% Si3N4 and 20% BN can approach 487.7 MPa, the fracture toughness reached 7.8MPa/m1/2. even the composite of 50% BN and 20% Si3N4 component can reach 200.5 MPa.The research results show that RMO/(Si3N4+BN) composites have excellent thermal shock resistance. The residual strength was bigger than the original values after once water quenching at the thermal shock temperature of 800℃, 1000℃and 1200℃. There are two reasons of this phenomenon, one is that the thermophysical properties of the composites were excellent; the other is the formation of a dense oxidation layer on the surface of the composites at high temperature, and the oxidation layer smoothed the surface and healed the micro-crack on the surface.The http://www.chinamagnets.biz results of thermal shock resistance calculation show that by optioning the composion, the composite show the superior thermal shock resistance. For instance, the first ,the second and the third thermal stress resistant factor of the composite (40Vol%BN,40Vol%Si3N4) approached 870929℃, 76478166 J·m-1·s-1 and 3.894.15×10-3m2·K·s-1. the composite can be used at a circumstance of 9861052℃temperature difference, the highest cooling velocity can be 51865538 K·s-1.The results of the oxidation experiment at the high temperature of the RMO/(Si3N4+BN) composites, show that a weight losses during oxidation because of the oxide of BN. A uniform silicate film was found at the surface of the composites. The formation of silicate films decline the velocity of the oxidation and resulting in the composites fairly good high temperature oxidation resistance.
AB3型合金的贮氢特性
AB3型合金的贮氢特性 Storing hydrogen by solid-state material is a very attractive manner since it allows for safe storage.However,the gravimetric hydrogen density of this manner is too low for mobility and transport applications,many efforts have therefore been made to develop new materials with higher energy density and better kinetic behavior.For instance,in search for new metal hydrides,recent attention has been dedicated to the family of AB3-type intermetallics.In general,AB3-type intermetallics crystallize either in the PuNi3-type rhombohedral Ring neodymium magnet structure(R-3m space group) or in the hexagonal CeNi3-type structure(P63/mmc space group),but with the difference in the long-range stacking arrangement only.The PuNi3-type rhombohedral structure can be considered as alternating stacking of AB5 (CaCu5,Haucke phase) and AB2(MgZn2,Laves phase) subunits.Nevertheless,the experimental studies on AB3-type intermetallics reveal that the reversibility in hydrogen storage is rather poor.The underlying mechanism responsible for this is not yet well understood,but indispensable for further improvement in performance. Considering the structural feature,we assume that these may be related to the AB2 subunit in AB3-type crystal structure.
To prove this assumption,in this paper,the hydrogen storage behaviors of AB3-type intermatallics were systematically studied and compared with those of AB2-type ones. First,various AB3- and AB2-type intermatallics were designed and prepared by changing the element for the A-side from La,Ce to Y,while that for the B-side was fixed as Ni(called as ANi3 and ANi2 samples hereafter).These samples were then subjected to the hydrogen absorption/desorption cycling under hydrogen gas and the electrochemically hydrogen charging/discharging in alkaline solution,respectively. Finally,the relevance of hydrogen storage properties of ANi3 intermetallics to the ANi2 subunits http://www.chinamagnets.biz in their crystal structures was discussed,based on the experimental results. The main results achieved in this paper are given as below:The ANi3 and ANi2 samples with nominal compositions,LaNi3,CeNi3,YNi3, LaY2Ni9,CeY2Ni9,LaNi2,CeNi2 and YNi2,were prepared by induction melting.The phase components of each sample were checked by X-ray diffraction(XRD),and the diffraction patterns were further analyzed by the Rietveld refinement method to obtain the lattice and structural parameters of the main phases.The results showed that the as-prepared ANi3 samples crystallized in the PuNi3-type structure(R-3m space group), except CeNi3 in the CeNi3-type structure(P63/mmc space group).For the ternary intermetallics LaY2Ni9,most of the La atoms lay on site 3a and Y atoms on site 6c; while CeY2Ni9 had a randomly distribution of Ce and Y over the two sites.In the solid-H2 reaction,all the ANi3 samples underwent hydrogen-induced amorphization(HIA) to some extent,and the tendency of HIA could be described in the order YNi3/LaY2Ni9
To prove this assumption,in this paper,the hydrogen storage behaviors of AB3-type intermatallics were systematically studied and compared with those of AB2-type ones. First,various AB3- and AB2-type intermatallics were designed and prepared by changing the element for the A-side from La,Ce to Y,while that for the B-side was fixed as Ni(called as ANi3 and ANi2 samples hereafter).These samples were then subjected to the hydrogen absorption/desorption cycling under hydrogen gas and the electrochemically hydrogen charging/discharging in alkaline solution,respectively. Finally,the relevance of hydrogen storage properties of ANi3 intermetallics to the ANi2 subunits http://www.chinamagnets.biz in their crystal structures was discussed,based on the experimental results. The main results achieved in this paper are given as below:The ANi3 and ANi2 samples with nominal compositions,LaNi3,CeNi3,YNi3, LaY2Ni9,CeY2Ni9,LaNi2,CeNi2 and YNi2,were prepared by induction melting.The phase components of each sample were checked by X-ray diffraction(XRD),and the diffraction patterns were further analyzed by the Rietveld refinement method to obtain the lattice and structural parameters of the main phases.The results showed that the as-prepared ANi3 samples crystallized in the PuNi3-type structure(R-3m space group), except CeNi3 in the CeNi3-type structure(P63/mmc space group).For the ternary intermetallics LaY2Ni9,most of the La atoms lay on site 3a and Y atoms on site 6c; while CeY2Ni9 had a randomly distribution of Ce and Y over the two sites.In the solid-H2 reaction,all the ANi3 samples underwent hydrogen-induced amorphization(HIA) to some extent,and the tendency of HIA could be described in the order YNi3/LaY2Ni9
Research on Drawing Process and Structure and Properties of Magnesium Alloy
Research on Drawing Process and Structure and Properties of Magnesium Alloy
In this paper,a kind of closed drawing device,with capacity of heating and temperature-controlling,and drawing die are designed.Extruding and drawing are used to form thin-walled WE43 magnesium alloy tubes ofΦ4.0mm×0.25mm and alternation rules of wall thickness of the tubes are discussed;drawing forces under different processing parameters are measured and effect of drawing processing parameter on drawing force is analyzed;effect of heat treatment on properties and structure of extruded WE43 magnesium is discussed,and impact of deformation Cube neodymium magnet degree on properties and structure of drawed WE43 magnesium alloy,as well as its deformation mechanics,is researched.The results show that drawing processing of magnesium alloy bars and tubes can be realized in the presence of drawing device and dies designed.Thin-walled magnesium alloy tubes ofΦ4.0mm×0.25mm formed through a series of crafts of extruding,drawing, machining and heat treatment have homogeneous wall thickness,good performance and structure and surface quality.
Mechanical properties of the tubes can reach:σ_b>200MPa,δ>15%.Multi-pass drawing and decreasing elongation coefficient can reduce circumferential compressive stresses which tubes bears during drawing,prevent effectively increasing tendency of wall thickness,and are also favorable to homogeneous wall-thickness;T4 heat treatment can also prevent the increasing tendency of wall thickness.The bigger the Elongation coefficient,the bigger the drawing force needed;drawing force first decline and then increase with the increasing of drawing velocity.When v equals to 0.25mm/s,drawing force is lowest,making that optimization of drawing velocity is realized.Drawing processing of tubes designed is feasible,and assurance coefficient K of all passes is much greater than 1, http://www.chinamagnets.biz making sure that no breaking occurs during drawing.Solution treatment can improve structure and properties of extruded WE43 magnesium alloy,and reduce probability of tubes overlapping during drawing.Through solution treatment of 525℃×8h,this alloy have excellent comprehensive properties in room temperature,rare-earth phases chang into fine particles and distribute homogeneously inα-matrix.Multi-pass drawing makes tensile strength of WE43 magnesium alloy increase and elongation decrease.Twin nucleation is main nucleation way of drawed magnesium alloy, and is favorable to recrystallization and refinement of magnesium alloy grains.When deformation degree is up to 84.2%,grain size reduces from 23μm to below 8μm.
In this paper,a kind of closed drawing device,with capacity of heating and temperature-controlling,and drawing die are designed.Extruding and drawing are used to form thin-walled WE43 magnesium alloy tubes ofΦ4.0mm×0.25mm and alternation rules of wall thickness of the tubes are discussed;drawing forces under different processing parameters are measured and effect of drawing processing parameter on drawing force is analyzed;effect of heat treatment on properties and structure of extruded WE43 magnesium is discussed,and impact of deformation Cube neodymium magnet degree on properties and structure of drawed WE43 magnesium alloy,as well as its deformation mechanics,is researched.The results show that drawing processing of magnesium alloy bars and tubes can be realized in the presence of drawing device and dies designed.Thin-walled magnesium alloy tubes ofΦ4.0mm×0.25mm formed through a series of crafts of extruding,drawing, machining and heat treatment have homogeneous wall thickness,good performance and structure and surface quality.
Mechanical properties of the tubes can reach:σ_b>200MPa,δ>15%.Multi-pass drawing and decreasing elongation coefficient can reduce circumferential compressive stresses which tubes bears during drawing,prevent effectively increasing tendency of wall thickness,and are also favorable to homogeneous wall-thickness;T4 heat treatment can also prevent the increasing tendency of wall thickness.The bigger the Elongation coefficient,the bigger the drawing force needed;drawing force first decline and then increase with the increasing of drawing velocity.When v equals to 0.25mm/s,drawing force is lowest,making that optimization of drawing velocity is realized.Drawing processing of tubes designed is feasible,and assurance coefficient K of all passes is much greater than 1, http://www.chinamagnets.biz making sure that no breaking occurs during drawing.Solution treatment can improve structure and properties of extruded WE43 magnesium alloy,and reduce probability of tubes overlapping during drawing.Through solution treatment of 525℃×8h,this alloy have excellent comprehensive properties in room temperature,rare-earth phases chang into fine particles and distribute homogeneously inα-matrix.Multi-pass drawing makes tensile strength of WE43 magnesium alloy increase and elongation decrease.Twin nucleation is main nucleation way of drawed magnesium alloy, and is favorable to recrystallization and refinement of magnesium alloy grains.When deformation degree is up to 84.2%,grain size reduces from 23μm to below 8μm.
Glass-forming Ability and the Mechanical Properties of Fe-based Bulk Metallic Glasses
Glass-forming Ability and the Mechanical Properties of Fe-based Bulk Metallic Glasses
In this paper, a series of Fe-based amorphous alloys were prepared by using raw industrial materials. The microstructure and phases constituent were investigated by employing scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. The thermodynamic characteristic and mechanical properties of amorphous samples has been obtained by means of differential scanning calorimetry (DSC) and electronic universal tester.The result shows Ball Neodymium Magnets that, the partial replacement of Fe with a certain amount Nb in Fe48Cr15Mo14C15B6Y2 alloy will increases its glass-forming ability and compressive fracture strength significantly. Among them, the Fe46Cr15Mo14Ci5B6Y2Nb2 alloy has the best glass-forming ability and the critical size for glass formation has reached 7mm in diameter; the Fe47Cr15Mo14C15B6Y2Nb1 alloy has the best compressive fracture strength of 3645.7 MPa.
The glass forming ability and mechanical properties of Fe64.5-x-yCoxMo14C15B6Er0.5My (x=3, y=2, 3; x=5, y=2, 3; M=Ni, Nb) alloys were studied. The results shows that the Fe64.5-x-yCoxMo14C15B6Er0.5Niy (x=3, y=2, 3; x=5, y=2, 3) and Fe59.5Co5Mo14C15B6Er0.5Nb2 alloys can be formed a bulk metallic glass (BMG) with a diameter of 2mm. The compressive tests show that the Fe58.5Co3Mo14C15B6Er0.5Ni3 amorphous alloys exhibit not only high fracture strength (3890MPa), but also large plastic deformation behavior (plastic http://www.chinamagnets.biz strains are 2.7%). While almost no plastic deformation was found for the Nb containing FeCoMoCBEr amorphous alloys.The effect of Er addition on the glass forming ability and mechanical properties of Fe65Mo12C15B6Ni2 alloys was investigated. The compressive tests show that Fe64.5Mo12C15B6Er0.5Ni2 alloy exhibits better compressive fracture strength of 3350.1MPa and plastic deformation of 2.6%, respectively. The fracture surfaces of Fe64Mo12C15B6Er1Ni2 alloy show many discontinuous venous patterns. The Fe63Mo12C15B6Er2Ni2 alloy has the best glass-forming ability and the critical size for glass formation has reached 3mm. The SEM results show that the fracture surfaces for the samples with plastic deformation present obviously tearing and viscous flow.
In this paper, a series of Fe-based amorphous alloys were prepared by using raw industrial materials. The microstructure and phases constituent were investigated by employing scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. The thermodynamic characteristic and mechanical properties of amorphous samples has been obtained by means of differential scanning calorimetry (DSC) and electronic universal tester.The result shows Ball Neodymium Magnets that, the partial replacement of Fe with a certain amount Nb in Fe48Cr15Mo14C15B6Y2 alloy will increases its glass-forming ability and compressive fracture strength significantly. Among them, the Fe46Cr15Mo14Ci5B6Y2Nb2 alloy has the best glass-forming ability and the critical size for glass formation has reached 7mm in diameter; the Fe47Cr15Mo14C15B6Y2Nb1 alloy has the best compressive fracture strength of 3645.7 MPa.
The glass forming ability and mechanical properties of Fe64.5-x-yCoxMo14C15B6Er0.5My (x=3, y=2, 3; x=5, y=2, 3; M=Ni, Nb) alloys were studied. The results shows that the Fe64.5-x-yCoxMo14C15B6Er0.5Niy (x=3, y=2, 3; x=5, y=2, 3) and Fe59.5Co5Mo14C15B6Er0.5Nb2 alloys can be formed a bulk metallic glass (BMG) with a diameter of 2mm. The compressive tests show that the Fe58.5Co3Mo14C15B6Er0.5Ni3 amorphous alloys exhibit not only high fracture strength (3890MPa), but also large plastic deformation behavior (plastic http://www.chinamagnets.biz strains are 2.7%). While almost no plastic deformation was found for the Nb containing FeCoMoCBEr amorphous alloys.The effect of Er addition on the glass forming ability and mechanical properties of Fe65Mo12C15B6Ni2 alloys was investigated. The compressive tests show that Fe64.5Mo12C15B6Er0.5Ni2 alloy exhibits better compressive fracture strength of 3350.1MPa and plastic deformation of 2.6%, respectively. The fracture surfaces of Fe64Mo12C15B6Er1Ni2 alloy show many discontinuous venous patterns. The Fe63Mo12C15B6Er2Ni2 alloy has the best glass-forming ability and the critical size for glass formation has reached 3mm. The SEM results show that the fracture surfaces for the samples with plastic deformation present obviously tearing and viscous flow.
Influence of Heat Treatment on Fatigue Behavior of Extruded Al-Mg-Ce Alloy
Influence of Heat Treatment on Fatigue Behavior of Extruded Al-Mg-Ce Alloy
Aluminum alloys have such characteristics as low density, high specific strength and rigidity, and have found a wide application in aeronautical and automotive industries. As the engineering structural materials, the fatigue fracture is one of their main failure forms. Obviously, the investigation on the fatigue behavior of the extruded Al-4%Mg-%xCe alloy with neodymium magnets different treatment statuses has important theory reference value and actual guiding significance for reliable usage and safety design of this alloy.In this investigation, the Al-4%Mg alloy is chosen as the master alloy. Through adding Ce as well as melting, casting, hot extrusion and heat treatment, the Al-4%Mg-xCe alloy with different processing statuses have been fabricated. The microstructures of the Al-4%Mg-xCe alloy are observed and analyzed using optical microscope. The low-cycle fatigue tests are performed at room temperature under different total strain amplitudes.
The influence of heat treatment on both fatigue deformation and fracture behavior of the Al-4%Mg-xCe alloy is determined.The observations on microstructures reveal that the amount of secondary phases gets decreased after solid solution treatment. For the Al-4%Mg-xCe alloy subjected to solution plus aging treatments, the disperse secondary phases will precipitate inside grains and at grain boundaries. In addition, it is noted that in the Al-4%Mg-xCe alloy subjected to aging treatment, the much more and smaller secondary phases appear.The results of fatigue tests show that the Al-4%Mg-xCe alloy subjected to different treatments can exhibit the cyclic hardening, softening and stable cyclic stress response, which mainly depends on the imposed total strain as well as http://www.chinamagnets.biz the treatment method. Compared with as-extruded Al-4%Mg-0.3%Ce alloy, the fatigue life of the alloy subjected to solution treatment increases at the higher or lower strain amplitude. for both Al-4%Mg-0.5%Ce and Al-4%Mg-1.0%Ce alloy, the fatigue lifetime increase after heat treatment. For the Al-4%Mg-xCe alloy with different processing statuses, the relation between plastic and elastic strain amplitudes as well as reversals to failure can be described by Coffin-Manson and Basquin equations, respectively. In addition, at the higher total strain amplitudes, a serrated flow can be observed on theσ-εhysteresis loop. It means that the so-called dynamic strain aging takes place during fatigue deformation.The fractographic observations reveal that under the fatigue loading conditions, the cracks initiate transgranularly at the surface of fatigue samples and propagate in a transgranular mode for the Al-4%Mg-xCe alloy with different treated statuses.
Aluminum alloys have such characteristics as low density, high specific strength and rigidity, and have found a wide application in aeronautical and automotive industries. As the engineering structural materials, the fatigue fracture is one of their main failure forms. Obviously, the investigation on the fatigue behavior of the extruded Al-4%Mg-%xCe alloy with neodymium magnets different treatment statuses has important theory reference value and actual guiding significance for reliable usage and safety design of this alloy.In this investigation, the Al-4%Mg alloy is chosen as the master alloy. Through adding Ce as well as melting, casting, hot extrusion and heat treatment, the Al-4%Mg-xCe alloy with different processing statuses have been fabricated. The microstructures of the Al-4%Mg-xCe alloy are observed and analyzed using optical microscope. The low-cycle fatigue tests are performed at room temperature under different total strain amplitudes.
The influence of heat treatment on both fatigue deformation and fracture behavior of the Al-4%Mg-xCe alloy is determined.The observations on microstructures reveal that the amount of secondary phases gets decreased after solid solution treatment. For the Al-4%Mg-xCe alloy subjected to solution plus aging treatments, the disperse secondary phases will precipitate inside grains and at grain boundaries. In addition, it is noted that in the Al-4%Mg-xCe alloy subjected to aging treatment, the much more and smaller secondary phases appear.The results of fatigue tests show that the Al-4%Mg-xCe alloy subjected to different treatments can exhibit the cyclic hardening, softening and stable cyclic stress response, which mainly depends on the imposed total strain as well as http://www.chinamagnets.biz the treatment method. Compared with as-extruded Al-4%Mg-0.3%Ce alloy, the fatigue life of the alloy subjected to solution treatment increases at the higher or lower strain amplitude. for both Al-4%Mg-0.5%Ce and Al-4%Mg-1.0%Ce alloy, the fatigue lifetime increase after heat treatment. For the Al-4%Mg-xCe alloy with different processing statuses, the relation between plastic and elastic strain amplitudes as well as reversals to failure can be described by Coffin-Manson and Basquin equations, respectively. In addition, at the higher total strain amplitudes, a serrated flow can be observed on theσ-εhysteresis loop. It means that the so-called dynamic strain aging takes place during fatigue deformation.The fractographic observations reveal that under the fatigue loading conditions, the cracks initiate transgranularly at the surface of fatigue samples and propagate in a transgranular mode for the Al-4%Mg-xCe alloy with different treated statuses.
2012年8月3日星期五
Steering Gear System Controller in Missile Based on Adaptive Fuzzy PID Algorithm
Steering Gear System Controller in Missile Based on Adaptive Fuzzy PID Algorithm
In this paper, aiming at the steering gear machinery in some missiles,adopting the combined configuration of small rare earth torque motor and harmonic drive reducer, a adaptive fuzzy strategy is designed. Considering the change with velocity and small damp of harmonic drive, adopting the characteristic of many methods of control, learn from other’s strong points to offset one’s weakness, the adaptive fuzzy PID control system is used here. Block Neodymium magnets At the same tine, a project which using infinite impulse response filter is put forward to improve the capability and remove noise.In the aspect of hardware system, the DSP control system with CAN2.0 and based on TMS320F2812 has been designed, which is more dependable. The testing result indicates that this control system has the merits such as good capability of anti-jamming, excellent control quality, and so on.At the end of the paper, all factors that affect system performance are analyzed, and http://www.999magnet.com optimization designs are presented.
In this paper, aiming at the steering gear machinery in some missiles,adopting the combined configuration of small rare earth torque motor and harmonic drive reducer, a adaptive fuzzy strategy is designed. Considering the change with velocity and small damp of harmonic drive, adopting the characteristic of many methods of control, learn from other’s strong points to offset one’s weakness, the adaptive fuzzy PID control system is used here. Block Neodymium magnets At the same tine, a project which using infinite impulse response filter is put forward to improve the capability and remove noise.In the aspect of hardware system, the DSP control system with CAN2.0 and based on TMS320F2812 has been designed, which is more dependable. The testing result indicates that this control system has the merits such as good capability of anti-jamming, excellent control quality, and so on.At the end of the paper, all factors that affect system performance are analyzed, and http://www.999magnet.com optimization designs are presented.
Design of the Steering Engine Control System for Missiles Based on DSP
Design of the Steering Engine Control System for Missiles Based on DSP
Missile steering engine system is a high-precision servo system, which is the implementation of the missile control system, and it is also an important component part of missile flight control system. The purpose of the study of this topic is to design a missile steering with precise, rapid real-time control of the digital control system. Steering system is mainly from the steering servo controller and driver institution which is composed by thulium motor and harmonic drive.In order to improve the steering engine control system’s dynamic and steady-state performance, improve Neodymium Magnets system response speed and torque control accuracy, this paper mainly completed the following work:First, the study of the paper from the steering engine drive and the composition of the work principle, establish a BLDCM the mathematical model and simulation modeling it.Secondly, according to the steering engine system characteristics and combining with the advantages of fuzzy control’s strong adaptability and PID control’s small steady-state error, this paper presents the system for the fuzzy PID control algorithm. The error of real-time steering engine angle between target angle and the transformation of error get a reasonable intelligent classification. Using fuzzy controller to replace the traditional steering servo controller to improve the control performance and get better of the dynamic and static response. In a building based on fuzzy PID control of the steering position control system, we use MATLAB / SIMULINK platform to conduct its control system simulation.Finally, in the study of the TMS320F2812DSP device’s structure of hardware and software and the characteristics of motor control, on this basis we design a DSP-core http://www.999magnet.com quad servo control system. Communication bus will messages the operational status of real-time data upload supremacy into the computer, and using Matlab software to Off-line analysis and evaluate the steering engine system.
Missile steering engine system is a high-precision servo system, which is the implementation of the missile control system, and it is also an important component part of missile flight control system. The purpose of the study of this topic is to design a missile steering with precise, rapid real-time control of the digital control system. Steering system is mainly from the steering servo controller and driver institution which is composed by thulium motor and harmonic drive.In order to improve the steering engine control system’s dynamic and steady-state performance, improve Neodymium Magnets system response speed and torque control accuracy, this paper mainly completed the following work:First, the study of the paper from the steering engine drive and the composition of the work principle, establish a BLDCM the mathematical model and simulation modeling it.Secondly, according to the steering engine system characteristics and combining with the advantages of fuzzy control’s strong adaptability and PID control’s small steady-state error, this paper presents the system for the fuzzy PID control algorithm. The error of real-time steering engine angle between target angle and the transformation of error get a reasonable intelligent classification. Using fuzzy controller to replace the traditional steering servo controller to improve the control performance and get better of the dynamic and static response. In a building based on fuzzy PID control of the steering position control system, we use MATLAB / SIMULINK platform to conduct its control system simulation.Finally, in the study of the TMS320F2812DSP device’s structure of hardware and software and the characteristics of motor control, on this basis we design a DSP-core http://www.999magnet.com quad servo control system. Communication bus will messages the operational status of real-time data upload supremacy into the computer, and using Matlab software to Off-line analysis and evaluate the steering engine system.
腈氯纶多功能吸附纤维的制备及性能研究
腈氯纶多功能吸附纤维的制备及性能研究
Ion exchange fiber has bigger specific surface area and faster speed of exchange and elution than ion-exchange resin.It can be applied to the preparations of electronic pure water,medical water and biological agent,the purification of industrial sewage, adsorption of poisonous and mephitic gases,the carrier of catalysts,the recovery of heavy metals and rare-earth element and so on.It is a new type ion-exchange material with broad developing prospects.The researches of new ion exchange fiber with much more excellent adsorption capacity have been set store by many countries due to the enhancement of people’s environment protection.The wet-spun absorbable AN-VDC copolymer fibers containing various contents of activated carbon were produced via coagulation stragety,whereas the ion exchange AN-VDC copolymer fibers were obtained with aq-hydrazine and hydrolysis in basic solution successively.The ion exchange fiber thus prepared with actived carbon’s adsorption property has great exchange capacity,short regeneration time,long service life,stable adsorption decoloring and other advantages;and may be used widely in many fields.The experiment showed that the new Special shape NdFeB magnets fiber is a type of more effective sorbent compared with actived carbon and actived carbon fiber in treating complex pollution.The character of this new adsorption fiber unmodified and modified has been investigated by using Scanning Electronic Microscopy(SEM),Differential Scanning Calorimetry(DSC),X-ray Diffraction(XRD),Infrared Spectroscopic Analysis(IR), specific surface analyzer and absorption spectrophotometer etc.In addition,the adsorption behavior,adsorption process and principle have been also studied particularly.The conclusions are showed as follows.
On keeping the property of actived carbon intact the particle diameter suitable for spinning is about 0.8μm.In this experiment,the temperature of drawn bath 70℃, the temperature of coagulation bath 6-10℃,coagulation bath concentration 55wt% and spinning speed 3.33m/min are the best spinning parameters.The actived carbon are distributing in fiber uniformityly.The property of heat resistance has been improved after mixing actived carbon in fiber.Adsorption capacity and adsorption speed both decreased after mixing actived carbon in fiber.Not only the actived carbons distributing mainly on surface of the fiber exert adsorption effect,but in amorphous region in fiber also exert adsorption effect.High Crystallization has low adsorption ability.By contrast,the orientation has little effect on adsorption.The pore and the micropore is the main factor to affect the adsorption capacity.The isothermal adsorption of actived carbon in fiber can be well described by Langmuir and Freundlich model.The effective diffusion coefficient Defof methyl orange in the actived carbon particle in polymer is 10-16. http://www.999magnet.com When the temperature is 50℃the fiber has good adsorption efficiency.The adsorption speed increase with the temperature rising.Entropy effectiveness is the main impetus of the actived carbon in fiber.The new fibers show a very high adsorption ability in the Pb2+and methylene blue co-existing solution.The maximum adsorption capacity of methylene blue and Pb2+ are 9.5mg.g-1and 487.8mg.g-1respectively.We initially think that the physical adsorption of actived carbon and ion exchange happened at the same time.It may be noticed that the chemical adsorption has great effect on physical adsorption.It has been found that Langmuir model is more fitable to describe the adsorption kinetic behavior than Freundlich on Pb2+on the obtained fibers.Also,Increasing the temperature may improve the fiber’s physical adsorption ability.The fibers have good adsorption efficiency when pH=7.
Ion exchange fiber has bigger specific surface area and faster speed of exchange and elution than ion-exchange resin.It can be applied to the preparations of electronic pure water,medical water and biological agent,the purification of industrial sewage, adsorption of poisonous and mephitic gases,the carrier of catalysts,the recovery of heavy metals and rare-earth element and so on.It is a new type ion-exchange material with broad developing prospects.The researches of new ion exchange fiber with much more excellent adsorption capacity have been set store by many countries due to the enhancement of people’s environment protection.The wet-spun absorbable AN-VDC copolymer fibers containing various contents of activated carbon were produced via coagulation stragety,whereas the ion exchange AN-VDC copolymer fibers were obtained with aq-hydrazine and hydrolysis in basic solution successively.The ion exchange fiber thus prepared with actived carbon’s adsorption property has great exchange capacity,short regeneration time,long service life,stable adsorption decoloring and other advantages;and may be used widely in many fields.The experiment showed that the new Special shape NdFeB magnets fiber is a type of more effective sorbent compared with actived carbon and actived carbon fiber in treating complex pollution.The character of this new adsorption fiber unmodified and modified has been investigated by using Scanning Electronic Microscopy(SEM),Differential Scanning Calorimetry(DSC),X-ray Diffraction(XRD),Infrared Spectroscopic Analysis(IR), specific surface analyzer and absorption spectrophotometer etc.In addition,the adsorption behavior,adsorption process and principle have been also studied particularly.The conclusions are showed as follows.
On keeping the property of actived carbon intact the particle diameter suitable for spinning is about 0.8μm.In this experiment,the temperature of drawn bath 70℃, the temperature of coagulation bath 6-10℃,coagulation bath concentration 55wt% and spinning speed 3.33m/min are the best spinning parameters.The actived carbon are distributing in fiber uniformityly.The property of heat resistance has been improved after mixing actived carbon in fiber.Adsorption capacity and adsorption speed both decreased after mixing actived carbon in fiber.Not only the actived carbons distributing mainly on surface of the fiber exert adsorption effect,but in amorphous region in fiber also exert adsorption effect.High Crystallization has low adsorption ability.By contrast,the orientation has little effect on adsorption.The pore and the micropore is the main factor to affect the adsorption capacity.The isothermal adsorption of actived carbon in fiber can be well described by Langmuir and Freundlich model.The effective diffusion coefficient Defof methyl orange in the actived carbon particle in polymer is 10-16. http://www.999magnet.com When the temperature is 50℃the fiber has good adsorption efficiency.The adsorption speed increase with the temperature rising.Entropy effectiveness is the main impetus of the actived carbon in fiber.The new fibers show a very high adsorption ability in the Pb2+and methylene blue co-existing solution.The maximum adsorption capacity of methylene blue and Pb2+ are 9.5mg.g-1and 487.8mg.g-1respectively.We initially think that the physical adsorption of actived carbon and ion exchange happened at the same time.It may be noticed that the chemical adsorption has great effect on physical adsorption.It has been found that Langmuir model is more fitable to describe the adsorption kinetic behavior than Freundlich on Pb2+on the obtained fibers.Also,Increasing the temperature may improve the fiber’s physical adsorption ability.The fibers have good adsorption efficiency when pH=7.
Neogene Sedimentary Evolution and Geochemistry in Tianshui Basin
Neogene Sedimentary Evolution and Geochemistry in Tianshui Basin
The Northeast margin of Qinghai-Tibetan plateau is consists of a series of mountain chains such as Qilian mountain,west Qinling,Xiangshan, Liupanshan and lots of basins such as Lanzhou,Linxia,Xining,Guide,Tianshui basin.In this paper we choise the tianshui basin to study the uplift of the Qinghai-Tibetan plateau.Tianshui basin was surround by three mountain chains which are qilian,west of qinling,liupanshan.In a more large scale it is the jont part of the huabei plate,Yangtze plate and qiangtang geological mass. The north of the tianshui basin is part of the Ordus and alashan mass,south of the basin is Yangtze palte and southwest is qiangtang mass.Tianshui baisin is also part of the Longzhong basin,Some main fault that across the north margin of west qinling control the basis structure of the basin.According to the rock property,rock granularity,sedimentary structure and texture,we have analysised the profile of the Ganquan,and demarcate the sedimentary face into 3 category,they are fluvial deposit system,alluvial fan deposit system and lacustrin deposit syetem.Block Neodymium magnets They present three main steps that
Qinghai-Tibetan plateau was deformed by the process of India-Eurasia collision happened during 35-30Ma,15-10Ma,8-6Ma.In orde to fully understand the structure of the basin we have checked 22 profiles across the basin,From the south to north of the basin,the stratm is thinning,it is accordance to the model of forland basin.And the sediments record the uplift of the mountain adjacent the basin,According to the mountain -basin coupling hypothesis,it is the best way to reconstruct the uplift of the Tibetan plateau.This paper presents geochemistry data of neogene clastic sedimentary rocks in Tianhui basin, systematic research leads to the following conclusion:(1)MgO、CaO、Nb、Sr、Th are rich and SiO2、Al2O3、Ba、Cr、Ni、Rb are deplete in the samples,the ratio Al2O3/TiO2、Cr/Zr、Cr/Th、Th/Sc in samples are also very high.These characters indicate that granitic diorite generated in all epoch located at south of Tianshui basin(west margin of Qinling mountain)control the geochemical composition of main provenance of the neogene sedimentary rocks,and another minor parent rock is basic-super basic ignenous rock generated as the ancient Qinling paleoocean closed.
The ratio K2O have been increasing in Tianshui Xiashan mud stone as time goby is another apparent character,we deem it result from the river that discharge into the basin exhumation K-rich magma rock gradually.(2)Low CIA and high ICV value indicate that weak chemical weathering in sourc region and low maturity of sedimentary rocks, then,with other evidence we can infer that the deposit rate is also low and Lack of sedimentary recycled product.(3)The thickness of strata become more and more thin from the south to north of the basin,and the sedimentary faces is also change from deep lake faces into lacustrine plain,combine with geochemistry tectonogram,we can infer Tianshui Xiashan mud stone are deposited in foreland tectonic setting.The geochemical signature of sedimentary rocks is mainly controlled by the parent petrology which generate in different tectonic setting.The early authors erect lots of element tectonic setting discrimination diagrams to infer the past tectonic activity of surrounding mountains under which sediments formed.Those diagrams have been widely used for twenty http://www.999magnet.com years.Studies have been carried to test the reliability of those diagrams.In this paper,we surveyed 173 samples from the same sedimentary basin,but in the twelve plot(Al2O3/SiO2、TiO2、K2O/Na2O、Al2O3/(CaO+Na2O)--(Fe2O3+MgO)diagram,K2O/Na2O--SiO2、SiO2/Al2O3--K2O/Na2O、Ti/Zr—La/Sc and Th-Co-Zr/10、La-Th、La/Y-Sc/Cr、Th-Sc-Zr/10、La-Th-Sc diagram)173 samples from the same sedimentary basin fell in different tectonic field.They do not work properly.So we can infer that it is the complex he nature of the source rocks,intensity and duration of weathering,sedimentary recycling,diagenesis,sorting and mixing cause the disagreement.We therefore recommend that these diagrams be used with prudence.
The Northeast margin of Qinghai-Tibetan plateau is consists of a series of mountain chains such as Qilian mountain,west Qinling,Xiangshan, Liupanshan and lots of basins such as Lanzhou,Linxia,Xining,Guide,Tianshui basin.In this paper we choise the tianshui basin to study the uplift of the Qinghai-Tibetan plateau.Tianshui basin was surround by three mountain chains which are qilian,west of qinling,liupanshan.In a more large scale it is the jont part of the huabei plate,Yangtze plate and qiangtang geological mass. The north of the tianshui basin is part of the Ordus and alashan mass,south of the basin is Yangtze palte and southwest is qiangtang mass.Tianshui baisin is also part of the Longzhong basin,Some main fault that across the north margin of west qinling control the basis structure of the basin.According to the rock property,rock granularity,sedimentary structure and texture,we have analysised the profile of the Ganquan,and demarcate the sedimentary face into 3 category,they are fluvial deposit system,alluvial fan deposit system and lacustrin deposit syetem.Block Neodymium magnets They present three main steps that
Qinghai-Tibetan plateau was deformed by the process of India-Eurasia collision happened during 35-30Ma,15-10Ma,8-6Ma.In orde to fully understand the structure of the basin we have checked 22 profiles across the basin,From the south to north of the basin,the stratm is thinning,it is accordance to the model of forland basin.And the sediments record the uplift of the mountain adjacent the basin,According to the mountain -basin coupling hypothesis,it is the best way to reconstruct the uplift of the Tibetan plateau.This paper presents geochemistry data of neogene clastic sedimentary rocks in Tianhui basin, systematic research leads to the following conclusion:(1)MgO、CaO、Nb、Sr、Th are rich and SiO2、Al2O3、Ba、Cr、Ni、Rb are deplete in the samples,the ratio Al2O3/TiO2、Cr/Zr、Cr/Th、Th/Sc in samples are also very high.These characters indicate that granitic diorite generated in all epoch located at south of Tianshui basin(west margin of Qinling mountain)control the geochemical composition of main provenance of the neogene sedimentary rocks,and another minor parent rock is basic-super basic ignenous rock generated as the ancient Qinling paleoocean closed.
The ratio K2O have been increasing in Tianshui Xiashan mud stone as time goby is another apparent character,we deem it result from the river that discharge into the basin exhumation K-rich magma rock gradually.(2)Low CIA and high ICV value indicate that weak chemical weathering in sourc region and low maturity of sedimentary rocks, then,with other evidence we can infer that the deposit rate is also low and Lack of sedimentary recycled product.(3)The thickness of strata become more and more thin from the south to north of the basin,and the sedimentary faces is also change from deep lake faces into lacustrine plain,combine with geochemistry tectonogram,we can infer Tianshui Xiashan mud stone are deposited in foreland tectonic setting.The geochemical signature of sedimentary rocks is mainly controlled by the parent petrology which generate in different tectonic setting.The early authors erect lots of element tectonic setting discrimination diagrams to infer the past tectonic activity of surrounding mountains under which sediments formed.Those diagrams have been widely used for twenty http://www.999magnet.com years.Studies have been carried to test the reliability of those diagrams.In this paper,we surveyed 173 samples from the same sedimentary basin,but in the twelve plot(Al2O3/SiO2、TiO2、K2O/Na2O、Al2O3/(CaO+Na2O)--(Fe2O3+MgO)diagram,K2O/Na2O--SiO2、SiO2/Al2O3--K2O/Na2O、Ti/Zr—La/Sc and Th-Co-Zr/10、La-Th、La/Y-Sc/Cr、Th-Sc-Zr/10、La-Th-Sc diagram)173 samples from the same sedimentary basin fell in different tectonic field.They do not work properly.So we can infer that it is the complex he nature of the source rocks,intensity and duration of weathering,sedimentary recycling,diagenesis,sorting and mixing cause the disagreement.We therefore recommend that these diagrams be used with prudence.
Selective Catalytic Reduction of NOx with Urea on Copper Catalysts of Modifacated Corderite
Selective Catalytic Reduction of NOx with Urea on Copper Catalysts of Modifacated Corderite
The danger of motorcars’ NOx output was more and more serious.Many scholars all over the world have been doing some research from early time,in order to improve the measures of exhaust purification.Selective Catalytic Reduction(SCR) process was most widely used.Now noble metals were not only easily poisoned but also facing the crisis of resource scarcity.Therefore,in recent years,studies with transition metals have attracted much attention.In this thesis,the cordierite honeycomb ceramics were modified by aluminum-sol appended C6H122N4 and Ba(ON3)2.The main factors which influence the specific surface area were optimized by orthogonal designed method and the surface area of carrier was 70 m2/g about 100 times lager than the former blank Segment neodymium magnets cordierite.The activity test indicated that the catalytic activity was improved under large air speed and low temperature.A sery of corderite supported CuO with different metal oxide was prepared by impregnation and their catalytic activity in selective catalytic reduction was systematically investigated by using the method of temperature progressing while urea was used as reductant.
The catalytic reactions were conducted in fixed-bed fluxion reactor.The high active catalyst Cu-Mn-Ni-O/Al2O3/CC was filtrated in mixed metal oxide catalysts of the Cu series,and its optimized preparation technic indicated that the conversion rate of NOx approximately reached to 100%when the reaction temperature was 400℃in air speed 5000h-1 and retained more than 78%when the reaction air speed was 5000 h-1～20000 h-1.The effect of the addition of Ce in Cu-Mn-Ni-O/Al2O3/CC was also researched.The results showed that catalyst activity is improved and active tempreture is debased,the conversion rate of NOx reached 54%at 150℃in air speed 5000 h-1,and NOx was completely converted at 300℃in air speed 5000 h-1.The range of air speed was enlarged to 5000 h-1～20000 h-1,and the conversion rate was improved by 16% when the reaction http://www.999magnet.com air speed was 40000h-1.The catalytic samples were characterized by BET,SEM-EDS,TPR and XPS techniques.The research results showed that the larger BET surface area and pore diameter,the more homogeneous display of catalysts on the suface of support and the more the active center was.The Cu element was also found above 50%in the surface elements of the support.In the Selective Catalytic Reduction process,the effect of the addition of Mn,Ni,Ce was also researched.The results showed that this addition could make the reduction peak move to lower temperature,accelarate the velocity of reaction and improve the reductant activity of NOx.Metal element of oxide existed in the forms of Cu(Ⅱ),Mn(Ⅱ),Mn(Ⅲ),Ni(Ⅱ) and Ce(Ⅳ) on the surface of catalyst,respectively.
The danger of motorcars’ NOx output was more and more serious.Many scholars all over the world have been doing some research from early time,in order to improve the measures of exhaust purification.Selective Catalytic Reduction(SCR) process was most widely used.Now noble metals were not only easily poisoned but also facing the crisis of resource scarcity.Therefore,in recent years,studies with transition metals have attracted much attention.In this thesis,the cordierite honeycomb ceramics were modified by aluminum-sol appended C6H122N4 and Ba(ON3)2.The main factors which influence the specific surface area were optimized by orthogonal designed method and the surface area of carrier was 70 m2/g about 100 times lager than the former blank Segment neodymium magnets cordierite.The activity test indicated that the catalytic activity was improved under large air speed and low temperature.A sery of corderite supported CuO with different metal oxide was prepared by impregnation and their catalytic activity in selective catalytic reduction was systematically investigated by using the method of temperature progressing while urea was used as reductant.
The catalytic reactions were conducted in fixed-bed fluxion reactor.The high active catalyst Cu-Mn-Ni-O/Al2O3/CC was filtrated in mixed metal oxide catalysts of the Cu series,and its optimized preparation technic indicated that the conversion rate of NOx approximately reached to 100%when the reaction temperature was 400℃in air speed 5000h-1 and retained more than 78%when the reaction air speed was 5000 h-1～20000 h-1.The effect of the addition of Ce in Cu-Mn-Ni-O/Al2O3/CC was also researched.The results showed that catalyst activity is improved and active tempreture is debased,the conversion rate of NOx reached 54%at 150℃in air speed 5000 h-1,and NOx was completely converted at 300℃in air speed 5000 h-1.The range of air speed was enlarged to 5000 h-1～20000 h-1,and the conversion rate was improved by 16% when the reaction http://www.999magnet.com air speed was 40000h-1.The catalytic samples were characterized by BET,SEM-EDS,TPR and XPS techniques.The research results showed that the larger BET surface area and pore diameter,the more homogeneous display of catalysts on the suface of support and the more the active center was.The Cu element was also found above 50%in the surface elements of the support.In the Selective Catalytic Reduction process,the effect of the addition of Mn,Ni,Ce was also researched.The results showed that this addition could make the reduction peak move to lower temperature,accelarate the velocity of reaction and improve the reductant activity of NOx.Metal element of oxide existed in the forms of Cu(Ⅱ),Mn(Ⅱ),Mn(Ⅲ),Ni(Ⅱ) and Ce(Ⅳ) on the surface of catalyst,respectively.
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