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1.
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Influence of tail-like magnetic field on O~+ ion distribution in the Martian magnetosphere
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史建魁 刘振兴《中国科学E辑(英文版)》,2001年第44卷第4期
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Based on the comparison with the Earth, using the LB magnetic field model, the distribution of O+ ion originating from the ionosphere in the Martian magnetosphere is theoretically studied under different conditions of the tail-like magnetic field. The results show that the tail-like magnetic field has influence on the O+ ion flux in the Martian magnetotail: ( i ) the O+ ion flux in the Martian tail will increase if the tail-like magnetic field increases; when the tail-like magnetic field increases from 5 nT to 20 nT, the O+ ion flux increases 3 times in the region of 2.8 Rm in the Martian tail; and ( ii ) the O + ion flux decreases with increasing intrinsic moment; when the intrinsic moment increases about 5 times, the flux decreases to one fourth in the region of 2.8 Rm in the Martian tail. According to the data on the O+ ion flux and theoretical result in this paper, the deduced Martian intrinsic moment is about 2 × 1021 Gcm3. This is consistent with the most recent observation by the USA satellite MG
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2.
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Microstructure of Sm-Fe Films Electrodeposited in a High Static Magnetic Field
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LOU Chang-sheng KOU Ying ZHANG Wei-qiang《钢铁研究学报(英文版)》,2012年第Z2期
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Sm-Fe alloy films were electrodeposited in a high static magnetic field with the magnetic flux is perpendicular to the electric current.The samples were prepared on Cu substance in an aqueous solution by constant voltage method.The magnetic flux density used in the experiments were 0 T,2 T and 4 T,respectively.The microstructures,preferential orientation,composition of samples were characterized by SEM(equipped with EDS),AFM and XRD,respectively.The results showed that the thickness of films increased,whereas the concentration of Sm in films ascended first and then descended with the increasing of the flux density.The crystal grains were coarsened under the magnetic fields.The morphology of grains changed from granular at 0 T,to rough at 2 T and to cauliflower like at 4 T.The AFM results confirmed the different roughness of samples.However,the external field has not influenced the orientation of samples significantly.
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3.
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Effects of electromagnetic field intensity on as-cast microstructures and mechanical properties of Al-Zn-Mg-Cu-Zr alloy
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左玉波 赵志浩 王启伟 崔建忠《中国有色金属学会会刊》,2006年第16卷第A03期
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Al-Zn-Mg-Cu-Zr ingots with diameter of 200 mm were made by low frequency electromagnetic casting （LFEC） and conventional direct chill （DC） casting process. The results show that under the low frequency electromagnetic field （25 Hz, 32 mT） the microstructures of LFEC ingot from the border to the center on the cross section are all equiaxed grains, and the grains are much finer and more uniform than that of DC ingot. The magnetic flux density plays an important role in the microstructure formation of LFEC ingots. With increasing the magnetic flux density from 0 mT to 32 mT, grains become finer （from about 120 μm to 30 μm） and more uniform. While, with increasing the magnetic flux density from 32 mT to 46 mT, the grains change much slowly. In the range of experimental parameters, the optimum magnetic flux density for LFEC process is found to be 32 mT.
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4.
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Physical Simulation of Mold-Filling Processing of Thin-Walled Castings under Traveling Magnetic Field 被引次数：1
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Yanqing SU Tiejun ZHANG Jingjie GUO Hongsheng DING Weisheng BI Jun JIA and Hengzhi FU1)School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China2)Department of Mechanical Engineering Tsinghua University Beijing 100084 China《材料科学技术学报》,2004年第20卷第1期
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Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its formation mechanism were obtained and discussed for thin-walled casting. The influences of magnetic field density on the filling ability, filling velocity and mold filling time have been studied. The differences in filling capability between gravity casting and casting under the traveling magnetic field have been compared. The results indicate that the mold filling ability of the gallium melt increases greatly under the condition of traveling magnetic field; the filling time is shortened from 18 s under gravity field to 3 s under the traveling magnetic field and average flow rate of the melt increases from 1.6 to 8.68 cm3/s; the change law of the cross-section morphology of the gallium melt during the mold filling is that at first, the cross-section area does not change, then it decreases gradual
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5.
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Numerical Simulation of Magnetic Field Distribution in Aluminum Melting Furnace With Electromagnetic Stirring
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CHEN Hong WU Li WANG Tong-min CAO Zhi-qiang LI Ting-ju《钢铁研究学报(英文版)》,2012年第Z1期
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In metallurgical processing,effective and reliable electromagnetic stirring of the melt is one of the prerequisites for higher productivity and improved process performance.Reasonable structure and electrical parameters of the stirrer are greatly significant on improving and enhancing the stirring quality.In this paper,ANSYS software is used to research the effect of stirrer parameters on magnetic field distribution in aluminum melting furnace.The results show that magnetic flux density distributes as two humps at the direction(X)of metal length.Magnetic flux density distributes as a hump at the direction(Z)of metal width,reaches its maximum at the pool center and decays gradually toward the edge.It is also demonstrated that magnetic flux density increases by 2.65mT,as kilo-ampere-turns increase by 2.The center distance between two coils changes the distribution of magnetic flux density rather than its magnitude,while the distance from coils to the bottom of molten aluminum changes the magnitude of magnetic flux density but no change of distribution.
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6.
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High-Frequency Induction Heating of Needle-Shaped Mg-Ferrite for Ablation Therapy of Human Cancer
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NAOHARA Takashi AONO Hiromichi MAEHARA Tsunehiro HIRAZAWA Hideyuki MATSUTOMO Shinya WATANABE Yuji《钢铁研究学报(英文版)》,2012年第Z2期
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For application as a novel ablation therapy of human cancer,the heating property of a needle-shaped Mg-ferrite prepared by a sintering technique was studied in a high-frequency induction field at 370 kHz.When inserted into cylindrical clay,the increase in temperature(AT)was 31.2℃for the specimen with a 1.5 mm diameter,while the1.0mm diameter specimen exhibited aΔT value of 15.7℃after the induction time of 1200s.TheΔT exhibited a high value of 57.9℃during the simultaneous insertion of 31.5mm diameter specimens.In the computer simulation images,the relatively lower magnetic flux density and concurrent negUgibly low current density were observed from the surface to the internal regions,being different from the behavior of a ferromagnetic Ni-rod with the same size.
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7.
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Effects of Fast-Ion Injection on a Magnetized Sheath near a Floating Wall
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李佳佳 胡章虎 宋远红 王友年《等离子体科学和技术》,2013年第15卷第1期
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A fully kinetic particle-in-cell/Monte Carlo model is employed to self-consistently study the effects of fast-ion injection on sheath potential and electric field profile in collisional magnetized plasma with a floating absorbing wall. The influences of the fast-ion injection velocity and density, the magnetic field and angle θ0 formed by the magnetic field and the x-axis on the sheath potential and electric field are discussed in detail. Numerical results show that increasing fast-ion injection density or decreasing injection velocity can enhance the potential drop and electric field in the sheath. Also, increasing the magnetic field strength can weaken the loss of charged particles to the wall and thus decrease the potential and electric field in the sheath. The time evolution of ion flux and velocity distribution on the wall is found to be significantly affected by the magnetic field.
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8.
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Effect of Traveling Magnetic Field on Mould-Filling Length of the A357 Melt during Casting THin Walled Plate 被引次数：1
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TiejunZHANG JingjieGUO等《材料科学技术学报》,2003年第19卷第1期
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In order to improver the mould filling ability ,the method for production of thin-walled castings in the traveling magnetic field was applied,The relationship between magnetic field density and input voltage as well as distance was investigated,and the mould filling length of A357 melt has been studied,The electromagnetic forces applied on the melt were also analyzed,The result shows that the mould-filling length of the melt increase rapidly with the increase of magnetic flux density,The mould filling lengths in gypsum upper mould and magnetic material upper mould were compared from the standpoint of application,It demonstrated that the steel upper mould is superior to gypsum mould.
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9.
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Characterization of high flux magnetized helium plasma in SCU-PSI linear device
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马小春 曹小岗 韩磊 张志艳 韦建军 芶富均《等离子体科学和技术》,2018年第2期
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A high-flux linear plasma device in Sichuan University plasma-surface interaction(SCU-PSI)based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors.In this paper,the helium plasma has been characterized by a double-pin Langmuir probe.The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T.The core density and ion flux of helium plasma have a strong dependence on the applied current,magnetic field strength and gas flow rate.It could reach an electron density of1.2?×?10~(19)m~(-3)and helium ion flux of 3.2?×?10~(22)m~(-2)s~(-1),with a gas flow rate of 4 standard liter per minute,magnetic field strength of 0.2 T and input power of 11 k W.With the addition of-80 Vapplied to the target to increase the helium ion energy and the exposure time of 2 h,the flat top temperature reached about 530°C.The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy.These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.
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10.
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Microstructure Evolution of Cu-6%Ag Alloys by Modified Unidirectional Solidification Under a Horizontal Static Magnetic Field
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ZUO Xiao-wei ZHAO Cong-cong MA Ming WANG En-gang HE Ji-cheng《钢铁研究学报(英文版)》,2012年第Z1期
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The microstructure evolution of Cu dendrites in Cu-6%Ag alloys by modified unidirectional solidification under a static magnetic field has been investigated experimentally and quantitatively.The results show that the proeutectic Cu dendrites are finer when they are closer to the water-cooling copper mould and the unidirectional effect is more obvious,which is attributed to the higher solidification velocity.The quantitative analysis of the microstructure indicates that with increasing external magnetic flux density,the primary arms of the proeutectic Cu dendrites are refined and along a given direction.The analysis indicates that it is both the thermoelectromagnetic convection effect by the external magnetic field and the branch effect of the dendrites.
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11.
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磁性聚合物微球在Cr(VI)吸附分离中的应用(英文)
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王强 官月平 刘翔 杨明珠 任秀峰《中国化学工程学报》,2012年第1期
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The magnetic poly-(methacrylate-divinyl benzene) microspheres with micron size were synthesized by modified suspension polymerization method.Adsorption of Cr(VI) from aqueous solution by magnetic poly-(MA-DVB) microspheres with surface amination was investigated.The adsorption processes were carried out under diversified conditions of pH value,adsorption time and temperature to evaluate the performance of the mag-netic microspheres.The optimum pH value for Cr(VI) adsorption was found as 3.The adsorption capacity increased with adsorption time and attained an optimum at 60 min.The adsorption processes for magnetic microspheres was endothermic reaction,and the adsorption capacity increased with increasing temperature.
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12.
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MAGNETIZATION BEHAVIOUR FOR TEXTURED BULK YBaCuO POLYCRYSTALLINE SUPERCONDUCTORS
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TANG Hong QIAO Guiwen CHUANG YuchiInstitute of Metal Research Chinese Academy of Sciences Shenyang ChinaXIANYU Ze WANG JinxingNortheastern University Shenyang China《金属学报(英文版)》,1994年第7卷第3期
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In present paper.study of magnetization behaviour was carried out for textured bulk YBaCuO polycrystalline superconductors synthesized by MTG process.Themagnetization behaviour apparently different from that of sintered samples was observed.Magnetization hysteresis measurements were performed for the texturedYBaCuO superconductors at 77K in ± 10kOe magnetic field range.Based on the results ofmagnetization hysteresis.the magnetic field dependence of critical current density(J)at77K was evaluated for the textured YBaCuO samples.The magnetic flux penetration intextured bulk YBaCuO polycrystalline superconductors was investigated at 77K throughthe magnetization hysteresis measurements under various maximum applied magnetic fields(H_M)and reasonable discussion for the phenomena was conducted in terms of Bean’s criti-cal state model.The enhancement of magnetic properties for textured bulk YBaCuOpolycrystalline superconductors is presumably attributed to the improvement ofmicrostructure in these samples.
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13.
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用活性炭吸附强化超滤过程脱除废水中染料的研究(英文)
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董亚楠 苏延磊 陈文娟 彭金明 张岩 姜忠义《中国化学工程学报》,2011年第19卷第5期
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In this study, orange G dye was efficiently removed from aqueous solution by ultrafiltration (UF) mem-brane separation enhanced with activated carbon adsorption. The powdered activated carbon (PAC) was deposited onto the UF membrane surface, forming an intact filter cake. The enhanced UF process simultaneously exploited the high water permeation flux of porous membrane and the high adsorption ability of PAC toward dye molecules. The influencing factors on the dye removal were investigated. The results indicated that with sufficient PAC incor-poration, the formation of intact PAC filtration cake led to nearly complete rejection for dye solution under opti-mized dye concentration and operation pressure, without large sacrificing the permeation flux of the filtration process. Typically, the dye rejection ratio increased from 43.6% for single UF without adsorption to nearly 100% for the en-hanced UF process, achieving long time continuous treatment with water permeation flux of 47 L·m 2·h 1. The pre-sent study demonstrated that adsorption enhanced UF may be a feasible method for the dye wastewater treatment.
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14.
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A Simulator for Producing of High Flux Atomic Oxygen Beam by Using ECR Plasma Source
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Shuwang DUO Meishuan LI and Yaming ZHANGShenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China《材料科学技术学报》,2004年第20卷第6期
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In order to study the atomic oxygen corrosion of spacecraft materials in low earth orbit environment, an atomic oxygen simulator was established. In the simulator, a 2.45 GHz microwave source with maximum power of 600 W was launched into the circular cavity to generate ECR (electron cyclotron resonance) plasma. The oxygen ion beam moved onto a negatively biased Mo plate under the condition of symmetry magnetic mirror field confine, then was neutralized and reflected to form oxygen atom beam. The properties of plasma density, electron temperature, plasma space potential and ion incident energy were characterized. The atomic oxygen beam flux was calibrated by measuring the mass loss rate of Kapton during the atomic oxygen exposure. The test results show that the atomic oxygen beam with flux of 1016-1017 atoms-cm-2·s-1 and energy of 5-30 eV and a cross section of φ80 mm could be obtained under the operating pressure of 10-1-10-3 Pa. Such a high flux source can provide accelerated simulation tests of mater
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15.
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Modeling and Simulation of Deflected Anode Erosion in Vacuum Arcs
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王立军 黄小龙 贾申利 周鑫 史宗谦《等离子体科学和技术》,2014年第16卷第3期
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In vacuum switch devices, the connection bus bar out of the vacuum interrupter will generate a transverse magnetic field in the arc column region, and under the influence of this magnetic field, the whole arc column will deflect from the electrode center, thus leading to deflected anode erosion. In this paper, a two-dimensional deflected anode erosion model is established, anode erosions under different deflection distance are simulated and analyzed, and results of anode surface temperature, anode melting and surface evaporation flux are obtained. The simulation results show that the deflected heat flux density will lead to deflected distribution of anode temperature, saturated vapor pressure and vapor flux correspondingly, and the morphology of the anode melting pool has also the same deflection. Moreover, the anode center temperature and its gradient along the y direction decrease with the increase of deflection distance. On the contrary, the temperature of the anode side surface, toward which the heat flux density deflects, increases with increasing deflection distance. Related experiments also verify the correctness of the model and simulation results.
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16.
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Two Dimension Finite Element Simulations on the Electromagnetic Containment in Twin-Roll Strip Casting
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PeiweiBAO HongshuangDI等《材料科学技术学报》,2003年第19卷第1期
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Distribution of magnetic field and electromagnetic force in twin-roll casting of steels was studied by the metod of numerical simulation in this paper,Two-dimension finite element model ,which includes the regions of melt ,stainless collar ,coil and magnetic core ,has been constructed,By solving magnetic vector potential formulations of quasi-static electromagnetic field,distribution of magnetic flux density and magnetic force at different molten heigh is determined,Calculated results showed that intensity of the distribution of magnetic flux density increased linearly with the increased coil current ;and the magnetic force in the melt increased as a quadratic cure with creased coil current ,More attention was given to the distribution of eddy current and magnetic force in the melt ,the confine effect at different molten height was also discussed.
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17.
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Genotoxic Effects of Superconducting Static Magnetic Fields （SMFs） on Wheat （Triticum aestivum） Pollen Mother Cells （PMCs）
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张萍萍 尹若春 陈治友 吴丽芳 余增亮《等离子体科学和技术》,2007年第9卷第2期
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The effects of superconducting static magnetic fields （SMFs） on the pollen mother cells （PMCs） of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities （0, 1, 3, 5 and 7 Tesla） for 5 h or different durations （1, 3 and 5 h） at a magnetic flux density of 7 Tesla. The seeds were germinated at 23℃ after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus （MN）, chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity （below 5 Tesla） showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.
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18.
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GIANT MAGNETO-IMPEDANCE OF PATTERNED FeSiB／Cu／FeSiB TRI-LAYER FILMS
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X.H. Mao Y. Zhou M.S. Wu and B.C. CaiKey Laboratory for Thin Film and Microfabrication of Ministry of Education Research Institute of Micro/ Nanometer Science and Technology Shanghai Jiaotong University Shanghai 200030 China《金属学报(英文版)》,2003年第16卷第5期
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Sensitive magnetic field sensor with good performances can be fabricated utilizing the giant magneto-impedance (GMI) effect of soft magnetic multi-layer thin films. The transverse and longitudinal GMI effect in patterned FeSiB/Cu/FeSiB tri-layer films with the change of external magnetic field and frequency were studied at the same time. The change of the impedance of the films with the external magnetic fieldand frequency was shown. Comparing the longitudinal and transverse effect, the transverse effect has a larger linear range from zero magnetic field to a quite large magnetic field at all frequencies, and the change still were not saturated until the external magnetic field reached 1.2×104A/m, which illustrated that the films can be utilized to detect larger magnetic fields than now presented GMI sensors.
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19.
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Simulation of Vacuum Arc Characteristics at Different Moments Under Power-Frequency Current
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王立军 杨鼎革 贾申利 王流火 史宗谦《等离子体科学和技术》,2012年第3期
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In this paper,based on the quasi-stationary magneto-hydrodynamic(MHD) model,vacuum arc characteristics are simulated and analyzed at different moments under power-frequency current.For a vacuum arc with sinusoidal current under a uniform axial magnetic field(AMF),simulation results show that at the moment of peak value current,maximal values appear in the ion number density,axial current density,heat flux density,electron temperature,plasma pressure and azimuthal magnetic field.At the same time,the distributions of these parameters along the radial position are mostly nonuniform as compared with those at other moments.In the first 1/4 cycle,the ion number density,axial current density and plasma pressure increase with time,but the growth rate decreases with time.Simulation results are partially compared with experimental results published in other papers.Simulations and experimental results both show that the arc light intensity near the cathode side is stronger than that near the anode side for diffusing vacuum arcs.
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20.
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Analysis of magnetotail flux rope events by ARTEMIS observations
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TIAN AnMin SHI QuanQi ZONG QiuGang DU Jian FU SuiYan DAI YaNan《中国科学:技术科学(英文版)》,2014年第57卷第5期
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Three earthward flowing magnetic flux ropes observed in the duskside plasma sheet at geocentric solar magnetospheric coordinate X~–55 Re by P1 and P2 of acceleration,reconnection,turbulence and electrodynamics of moon’s interaction with the sun mission during 13:00–15:00 UT on July 3,2012,were studied.The morphologies of the flux ropes were studied in detail based on Grad-Shfranov reconstruction method and electronic pitch angle distribution data.It is found that(1)the flux rope cross-sectional dimensions are 1.0 Re×0.78 Re,1.3 Re×0.78 Re,and 2.5 Re×1.25 Re,respectively.The magnetic field lines were asymmetric about the center with field line compression on both sides of the current sheet at the leading region;(2)the electron energy flux data presented asymmetry with larger electron flux and lower temperature in the precursor region.The flux ropes were blocked by the resistance of compressed particle density in the front central plasma sheet and the enhanced magnetic field on its sides;and(3)it is found that the flux rope has a layered structure.From inside out,event 1 can be divided into three regions,namely electronic depletion core region,closed field line region,and the caudal area possible with fields connected with the ionosphere.It suggests that the flux ropes cannot merge with the tail magnetic field lines near the lunar orbit.Especially,the flux rope asymmetrical shape reflects the different reconnection processes that caused it on both sides of the magnetic structure.The events shown in this paper support the multiple X-line magnetic reconnection model for flux ropes with in situ observations.
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