The characteristics of lattice structures can make crystal possess distinct anisotropic features, such as the varying magnetism in different crystal orientations and different directions. The anisotropic magnetism can...The characteristics of lattice structures can make crystal possess distinct anisotropic features, such as the varying magnetism in different crystal orientations and different directions. The anisotropic magnetism can also cause the free energy to vary in different orientations of crystal in a magnetic field(magnetic anisotropy energy). Magneto-anisotropy can make the crystal rotate by the magnetic force moment on the crystal with the easy axis towards the direction of the magnetic field, and can also promote the preferential growth along a certain crystal direction at the lowest energy state.By solidification, vapor-deposition, heat treatment, slip casting and electrodeposition under magnetic field, the crystal structure with high grain orientation is obtained in a variety of binary eutectics, peritectic alloys, multicomponent alloys and high temperature superconducting materials. This makes it possible to fabricate texture-functional material by using high magnetic field and magneto-crystalline anisotropy of crystal. The purpose of this article is to review some recent progress of the orientation and alignment in material processing under a high magnetic field.展开更多
Conductive polyaniline(PAn-_M and PAn-_O) doped with dodecylbenzene sulfonic acid(DBSA) was synthesized by using emulsion polymerization method in the presence of a constant magnetic field(0.4 T) and the absence of ma...Conductive polyaniline(PAn-_M and PAn-_O) doped with dodecylbenzene sulfonic acid(DBSA) was synthesized by using emulsion polymerization method in the presence of a constant magnetic field(0.4 T) and the absence of magnetic field, respectively.The effects of magnetic field on the microscopic morphology and orientation structure of PAn were generally analyzed and characterized by using transmission electron microscope(TEM),X-ray diffraction(XRD) and through the conductivity anisotropy of unit resistance of t...展开更多
The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling (CSR) of different mismatched speed ratio (MSR) and annealed in magnetic field under hyd...The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling (CSR) of different mismatched speed ratio (MSR) and annealed in magnetic field under hydrogen were presented.Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.展开更多
PAN fibers pre-oxidized at 240℃, 260℃, 280℃, 300℃ were treated in 8 T, 12 T, 16 T high magnetic fields, respectively. The experimental result implied that there were two kinds of magnetic units cyan and carbon-nit...PAN fibers pre-oxidized at 240℃, 260℃, 280℃, 300℃ were treated in 8 T, 12 T, 16 T high magnetic fields, respectively. The experimental result implied that there were two kinds of magnetic units cyan and carbon-nitrogen heterocycle in pre-oxidized PAN fibers, and the movement of magnetic units resulted in changes of orientation structure of pre-oxidized PAN fibers in high magnetic fields. Overall orientation increased with increase of magnetic field intensity and extension of processing time, whereas change of crystalline orientation depended on magnetic field intensity and content of carbon-nitrogen heterocycle due to the competition of two magnetic units. Furthermore, magnetic fields induced the conversion from amorphous region to crystal region and improved crystalline orooerties of ore-oxidized PAN fibers.展开更多
The effect of the orientation magnetic field on the permanent magnetism of Nd-Fe-B sintermagnets is investigated. The results show that the variation law of magnetism with orientation field obviously changes at the cr...The effect of the orientation magnetic field on the permanent magnetism of Nd-Fe-B sintermagnets is investigated. The results show that the variation law of magnetism with orientation field obviously changes at the critical orientation field and the intensity of the orientation field should he determined by the dimension ratio of the magnet for effectively utilizing its magnetic energy product.展开更多
Permanent magnet rings are presented, which exploit the image effect in the surrounding circular iron shields. The theory is given for a general permanent ring when the magnetization orientation at each coordinate ang...Permanent magnet rings are presented, which exploit the image effect in the surrounding circular iron shields. The theory is given for a general permanent ring when the magnetization orientation at each coordinate angle ψ changes by =(n+1)ψ, where n is a positive or negative integer. For the uniformly magnetized case n=-1, the permanent ring produces no field in its bore, and the field is that of a dipole outside. When the ring is surrounded by a soft iron shield, its field becomes uniform in the bore, and zero outside the ring. The field can be varied continuously by moving the iron shield along the magnet axis. A small variable field device was constructed by using NdFeB permanent rings, which produced a field flux density of 0-0.5 T in the central region.展开更多
Many animal species have been proven to use the geomagnetic field for their navigation, but the biophysical mechanism of magnetoreception has remained enigmatic. In this paper, we present a special biophysical model t...Many animal species have been proven to use the geomagnetic field for their navigation, but the biophysical mechanism of magnetoreception has remained enigmatic. In this paper, we present a special biophysical model that consists of magnetite-based and radical-pair-based mechanisms for avian magnetoreception. The amplitude of the resultant magnetic field around the magnetic particles corresponds to the geomagnetic field direction and affects the yield of singlet/triplet state products in the radical-pair reactions. Therefore, in the proposed model, the singlet/triplet state product yields are related to the geomagnetic field information for orientational detection. The resultant magnetic fields corresponding to two materials with different magnetic properties are analyzed under different geomagnetic field directions. The results show that ferromagnetic particles in organisms can provide more significant changes in singlet state products than superparam- agnetic particles, and the period of variation for the singlet state products with an included angle in the geomagnetic field is approximately 180 when the magnetic particles are ferromagnetic materials, consistent with the experimental results obtained from the avian magnetic compass. Further, the calculated results of the singlet state products in a reception plane show that the proposed model can explain the avian magnetoreception mechanism with an inclination compass.展开更多
Effect of high static magnetic field on the dendritic morphology and growth direction in directionally solidified Al-10 wt.%Zn alloy were studied by three-dimensional(3D) X-ray micro-computed tomography, Electron Back...Effect of high static magnetic field on the dendritic morphology and growth direction in directionally solidified Al-10 wt.%Zn alloy were studied by three-dimensional(3D) X-ray micro-computed tomography, Electron Back-scattered Diffraction(EBSD) and X-ray Diffraction(XRD). The application of high static axial magnetic field(5T) during directional solidification was found to destabilize the solid/liquid interface and cause the growth direction of dendrite deviate from thermal gradient, leading to irregular solid/liquid interfacial shape and cellular to dendritic morphology transition. The thermoelectric magnetic convection(TEMC) caused by the interaction of thermoelectric effect and magnetic field was supposed to be responsible for the transition. In addition, the EBSD and XRD results confirm that the preferred growth direction of α-Al was found to transform from the traditionally expected <100> to<110>. The dendrite orientation transition(DOT) in Al-10 wt.%Zn alloy can be attributed to the effect of applied magnetic field on the anisotropy of crystal during solidification. The result indicates the potential application of high static magnetic field in altering the morphology and preferred growth direction of dendrite during directional solidification.展开更多
We investigated the effect of aligning crystal orientation in the microstructures containing sub micro-sized grains on the thermoelectric properties for polycrystalline Bi-Te materials.Bi-Te powder,prepared through th...We investigated the effect of aligning crystal orientation in the microstructures containing sub micro-sized grains on the thermoelectric properties for polycrystalline Bi-Te materials.Bi-Te powder,prepared through the conventional pulverization process,was sufficiently dispersed in an appropriate solvent,and then was formed into c-axis aligned green bodies under a designated high magnetic field.The green bodies were sintered with spark-plasma-sintering machine.The degree of crystal alignment of sintered bodies was examined with the electron-back-scatter-diffraction SEM and the X-ray diffraction patterns.It was observed that for both p and n type thermoelectric Bi-Te materials,aligning crystal orientation properly made electrical resistivity decreased with keeping Seebeck coefficient and thermal conductivity remained unchanged.As a typical result,the aligned Bi-Te material with the magnetic field of 10 tesla showed 30%enhancement of the thermoelectric performance.展开更多
A fully coupled 3-dimensional numerical model is used to analyse the effect of magnetic field orientation on dendritic growth.For materials that exhibit a significant thermoelectric power,the results show significant ...A fully coupled 3-dimensional numerical model is used to analyse the effect of magnetic field orientation on dendritic growth.For materials that exhibit a significant thermoelectric power,the results show significant differences in the dendritic morphology for different orientations of the field.These variations can be attributed to fluid flow generated through Thermoelectric Magnetohydrodynamics.A simplified,steady-state,low-field solution during the early stages of growth is used to describe how the fluid flow alters with the orientation of the field and how these flow features can lead to the final morphologies for well developed dendrites.展开更多
The experimental results show that the coercivity of Nd-Fe-B sintermagnet decreases with increasing of the grain alignment degree of the magnets (i.e. decreasing of the orientation distribution coefficient σ).The coe...The experimental results show that the coercivity of Nd-Fe-B sintermagnet decreases with increasing of the grain alignment degree of the magnets (i.e. decreasing of the orientation distribution coefficient σ).The coercivities of the magnets with different orientation degree are calculated based on the pinning,nucleation and starting field theory,respectively.The comparison of the calculated values with the experimental results shows that the theoretical results are deviating from the experiments seriously for both pinning mechanism and nucleation mechanism. In contrast with that,the calculated values based on the starting field theory are in good agreement with the experimental results.展开更多
In this research,sintering Fe-6.5wt%Si Compact specimen in static magnetic field is proposed for preparing high silicon steel.It is found that the densifications of the compacts are affected remarkably by superimposin...In this research,sintering Fe-6.5wt%Si Compact specimen in static magnetic field is proposed for preparing high silicon steel.It is found that the densifications of the compacts are affected remarkably by superimposing magnetic field.The density of the compacts can be increased when the MFD is higher than 0.2 T.The highest relative density of the samples is 97.2%.The magnetic property of silicon steel could be improved when superimpose static magnetic field in sintering process,the permeability of the compact are two times of that without magnetic field,and the magnetic property parallel to the direction of the magnetic field was evidently higher than that in perpendicular direction.展开更多
The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-...The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-Mg demonstrate a preferred orientation due to the magnetic driving force.In addition,high magnetic fields can promote the growth of the long period ordered structure(LPS) phase to the grain interior.And the corresponding mechanisms are also discussed in this article.展开更多
We have investigated the effects of high magnetic fields on the microstructures and magnetic properties of Fe-Si-O films deposited by RF sputtering. Three typical sample appearances, hole-in-center, phase-separation a...We have investigated the effects of high magnetic fields on the microstructures and magnetic properties of Fe-Si-O films deposited by RF sputtering. Three typical sample appearances, hole-in-center, phase-separation and hybridization were obtained for the Fe-Si-O films prepared in the oxygen-argon flow ratio VO2/Vtotal【1.0%, magnetic field Bappl≤1.0 T regime, indicating that not only the distribution of plasma but also the angular distribution of sputtered atoms are influenced by a high magnetic fleld. In the oxygen-argon flow ratio VO3/Vtotal】2.0%, magnetic field Bappl≥2.0 T regime, strong (110) orientation of Fe3O4 grains and larger remanence and coercivity measured in the direction normal to the film plane appeared in the Fe-Si-O films. This result indicates that the high magnetic fields not only orient the Fe-Si-O film but also induce remarkable perpendicular magnetic anisotropy during the deposition.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1560202,51690162,and 51604172)the National Science and Technology Major Project "Aeroengine and Gas Turbine",China(Grant No.2017-VII-0008-0102)the Shanghai Science and Technology Project,China(Grant No.17JC1400602)
文摘The characteristics of lattice structures can make crystal possess distinct anisotropic features, such as the varying magnetism in different crystal orientations and different directions. The anisotropic magnetism can also cause the free energy to vary in different orientations of crystal in a magnetic field(magnetic anisotropy energy). Magneto-anisotropy can make the crystal rotate by the magnetic force moment on the crystal with the easy axis towards the direction of the magnetic field, and can also promote the preferential growth along a certain crystal direction at the lowest energy state.By solidification, vapor-deposition, heat treatment, slip casting and electrodeposition under magnetic field, the crystal structure with high grain orientation is obtained in a variety of binary eutectics, peritectic alloys, multicomponent alloys and high temperature superconducting materials. This makes it possible to fabricate texture-functional material by using high magnetic field and magneto-crystalline anisotropy of crystal. The purpose of this article is to review some recent progress of the orientation and alignment in material processing under a high magnetic field.
基金supported by the National Natural Science Foundation of China(No.20176066).
文摘Conductive polyaniline(PAn-_M and PAn-_O) doped with dodecylbenzene sulfonic acid(DBSA) was synthesized by using emulsion polymerization method in the presence of a constant magnetic field(0.4 T) and the absence of magnetic field, respectively.The effects of magnetic field on the microscopic morphology and orientation structure of PAn were generally analyzed and characterized by using transmission electron microscope(TEM),X-ray diffraction(XRD) and through the conductivity anisotropy of unit resistance of t...
文摘The magnetic properties and textures of grain oriented silicon steel with different thickness rolled by cross shear rolling (CSR) of different mismatched speed ratio (MSR) and annealed in magnetic field under hydrogen were presented.Effects of the factors such as thickness and mismatched speed ratio on the magnetic properties and recrystallization texture were analyzed and the recrystallization principles in magnetic field annealing were discussed. The study would provide a new route for mass production of high quality ultra-thin grain oriented silicon steel strip.
基金Funded by the National Natural Science Foundation of China(51073098)the Open Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University),China(KF200901)
文摘PAN fibers pre-oxidized at 240℃, 260℃, 280℃, 300℃ were treated in 8 T, 12 T, 16 T high magnetic fields, respectively. The experimental result implied that there were two kinds of magnetic units cyan and carbon-nitrogen heterocycle in pre-oxidized PAN fibers, and the movement of magnetic units resulted in changes of orientation structure of pre-oxidized PAN fibers in high magnetic fields. Overall orientation increased with increase of magnetic field intensity and extension of processing time, whereas change of crystalline orientation depended on magnetic field intensity and content of carbon-nitrogen heterocycle due to the competition of two magnetic units. Furthermore, magnetic fields induced the conversion from amorphous region to crystal region and improved crystalline orooerties of ore-oxidized PAN fibers.
文摘The effect of the orientation magnetic field on the permanent magnetism of Nd-Fe-B sintermagnets is investigated. The results show that the variation law of magnetism with orientation field obviously changes at the critical orientation field and the intensity of the orientation field should he determined by the dimension ratio of the magnet for effectively utilizing its magnetic energy product.
文摘Permanent magnet rings are presented, which exploit the image effect in the surrounding circular iron shields. The theory is given for a general permanent ring when the magnetization orientation at each coordinate angle ψ changes by =(n+1)ψ, where n is a positive or negative integer. For the uniformly magnetized case n=-1, the permanent ring produces no field in its bore, and the field is that of a dipole outside. When the ring is surrounded by a soft iron shield, its field becomes uniform in the bore, and zero outside the ring. The field can be varied continuously by moving the iron shield along the magnet axis. A small variable field device was constructed by using NdFeB permanent rings, which produced a field flux density of 0-0.5 T in the central region.
基金Project supported by the State Key Program of the National Natural Science Foundation of China (Grant No. 51037006)the State Key Development Program for Basic Research of China (Grant No. 2011CB503702)the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 51207155)
文摘Many animal species have been proven to use the geomagnetic field for their navigation, but the biophysical mechanism of magnetoreception has remained enigmatic. In this paper, we present a special biophysical model that consists of magnetite-based and radical-pair-based mechanisms for avian magnetoreception. The amplitude of the resultant magnetic field around the magnetic particles corresponds to the geomagnetic field direction and affects the yield of singlet/triplet state products in the radical-pair reactions. Therefore, in the proposed model, the singlet/triplet state product yields are related to the geomagnetic field information for orientational detection. The resultant magnetic fields corresponding to two materials with different magnetic properties are analyzed under different geomagnetic field directions. The results show that ferromagnetic particles in organisms can provide more significant changes in singlet state products than superparam- agnetic particles, and the period of variation for the singlet state products with an included angle in the geomagnetic field is approximately 180 when the magnetic particles are ferromagnetic materials, consistent with the experimental results obtained from the avian magnetic compass. Further, the calculated results of the singlet state products in a reception plane show that the proposed model can explain the avian magnetoreception mechanism with an inclination compass.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 51690162, 51604171 and 51701112)China Postdoctoral Science Foundation (Grant Nos. 2017T100291 and 2017M611530)+1 种基金Shanghai Municipal Science and Technology Commission (No. 17JC1400602)open funding of State Key Laboratory of Solidification Processing in NWPU (SKLSP201602 and SKLSP201706)
文摘Effect of high static magnetic field on the dendritic morphology and growth direction in directionally solidified Al-10 wt.%Zn alloy were studied by three-dimensional(3D) X-ray micro-computed tomography, Electron Back-scattered Diffraction(EBSD) and X-ray Diffraction(XRD). The application of high static axial magnetic field(5T) during directional solidification was found to destabilize the solid/liquid interface and cause the growth direction of dendrite deviate from thermal gradient, leading to irregular solid/liquid interfacial shape and cellular to dendritic morphology transition. The thermoelectric magnetic convection(TEMC) caused by the interaction of thermoelectric effect and magnetic field was supposed to be responsible for the transition. In addition, the EBSD and XRD results confirm that the preferred growth direction of α-Al was found to transform from the traditionally expected <100> to<110>. The dendrite orientation transition(DOT) in Al-10 wt.%Zn alloy can be attributed to the effect of applied magnetic field on the anisotropy of crystal during solidification. The result indicates the potential application of high static magnetic field in altering the morphology and preferred growth direction of dendrite during directional solidification.
基金Item Sponsored by Energy Efficiency&Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy,Republic of Korea(2007EID11P050000)the DGIST Basic Research Program of the Ministry of Education,Science and Technology(MoEST),Republic of Korea(12-EN-01)
文摘We investigated the effect of aligning crystal orientation in the microstructures containing sub micro-sized grains on the thermoelectric properties for polycrystalline Bi-Te materials.Bi-Te powder,prepared through the conventional pulverization process,was sufficiently dispersed in an appropriate solvent,and then was formed into c-axis aligned green bodies under a designated high magnetic field.The green bodies were sintered with spark-plasma-sintering machine.The degree of crystal alignment of sintered bodies was examined with the electron-back-scatter-diffraction SEM and the X-ray diffraction patterns.It was observed that for both p and n type thermoelectric Bi-Te materials,aligning crystal orientation properly made electrical resistivity decreased with keeping Seebeck coefficient and thermal conductivity remained unchanged.As a typical result,the aligned Bi-Te material with the magnetic field of 10 tesla showed 30%enhancement of the thermoelectric performance.
文摘A fully coupled 3-dimensional numerical model is used to analyse the effect of magnetic field orientation on dendritic growth.For materials that exhibit a significant thermoelectric power,the results show significant differences in the dendritic morphology for different orientations of the field.These variations can be attributed to fluid flow generated through Thermoelectric Magnetohydrodynamics.A simplified,steady-state,low-field solution during the early stages of growth is used to describe how the fluid flow alters with the orientation of the field and how these flow features can lead to the final morphologies for well developed dendrites.
文摘The experimental results show that the coercivity of Nd-Fe-B sintermagnet decreases with increasing of the grain alignment degree of the magnets (i.e. decreasing of the orientation distribution coefficient σ).The coercivities of the magnets with different orientation degree are calculated based on the pinning,nucleation and starting field theory,respectively.The comparison of the calculated values with the experimental results shows that the theoretical results are deviating from the experiments seriously for both pinning mechanism and nucleation mechanism. In contrast with that,the calculated values based on the starting field theory are in good agreement with the experimental results.
基金Item Sponsored by National Natural Science Foundation of China[No.51034010]
文摘In this research,sintering Fe-6.5wt%Si Compact specimen in static magnetic field is proposed for preparing high silicon steel.It is found that the densifications of the compacts are affected remarkably by superimposing magnetic field.The density of the compacts can be increased when the MFD is higher than 0.2 T.The highest relative density of the samples is 97.2%.The magnetic property of silicon steel could be improved when superimpose static magnetic field in sintering process,the permeability of the compact are two times of that without magnetic field,and the magnetic property parallel to the direction of the magnetic field was evidently higher than that in perpendicular direction.
基金Item Sponsored by the Fundamental Research Funds for the Central University[NO.DUT12JN02]
文摘The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-Mg demonstrate a preferred orientation due to the magnetic driving force.In addition,high magnetic fields can promote the growth of the long period ordered structure(LPS) phase to the grain interior.And the corresponding mechanisms are also discussed in this article.
基金the Key TeacherSupporting Project of the National Education Committee (Grant No. G0032), and performed in the High Field Center for Superconducing Materials, IMR, Tohoku University, Sendai, Japan.
文摘We have investigated the effects of high magnetic fields on the microstructures and magnetic properties of Fe-Si-O films deposited by RF sputtering. Three typical sample appearances, hole-in-center, phase-separation and hybridization were obtained for the Fe-Si-O films prepared in the oxygen-argon flow ratio VO2/Vtotal【1.0%, magnetic field Bappl≤1.0 T regime, indicating that not only the distribution of plasma but also the angular distribution of sputtered atoms are influenced by a high magnetic fleld. In the oxygen-argon flow ratio VO3/Vtotal】2.0%, magnetic field Bappl≥2.0 T regime, strong (110) orientation of Fe3O4 grains and larger remanence and coercivity measured in the direction normal to the film plane appeared in the Fe-Si-O films. This result indicates that the high magnetic fields not only orient the Fe-Si-O film but also induce remarkable perpendicular magnetic anisotropy during the deposition.