VR. SobolO.N MazurenkoA.A. Drozd and B.B. Boiko(Institute of Solid State and Semiconductor Physics ASB
,
P. Brovka Str.
,
17
,
220072 Minsk
,
Belarus)
金属学报(英文版)
Peculiarities of low temperature charge transport and enerpy accumulation in alu-minum devices are investigated by means of study of cylindrical conductors having a rudial cuerent fiow between inner and outer concentric contracts. Azimuthal current and, connected with it, self magnetic field are investigated in a wide range of radial current density up to 6000 A/cm2 under an external magnetic field up to 8 T Electron scattering processes are investigated and it is shown that relaxation electron mechanisms are determined by strong temperature dependence on account of high sus-ceptibility of scattering to anisotropy of electron dispersion law. The role of thermal phonons is investigated through an effective averaged conductivity tensor of polycrystalline medium. Using data of self magnetic self distribution on sample surface an energy density of self magnetic field is estimated. It is shown that at T=4.2 K average energy of self field may achieve at least 1 J/cm3. Using data of relaxation processes at temperature of liquid hydrogen it is established that self magnetic field must be a third of helium magnitude with respective self magnetic enengy density, spiral motion of carriers in this geometry being regarded as a current coils in usual inductive element.
关键词:
energy storage
,
null
,
null
,
null
VR. SoBolo.N. Mazurenkoand A.A. Drozd(Institute of Solid State and Semiconductor Physics
,
ASB P. Brovka Str.
,
17
,
Minsk 220072
,
Belarus)
金属学报(英文版)
Galvanomagnetic properties of metals at boiling point of liquid helium and some prob-lems relating to Joule heating in cylinder conductors are investigated by the method of voltage current characteristics. Radial current under an external coaxial magnetic field is used to get high magnetoresistance of conductor. High level of magnetore-sistance in this geometry offers the possibility to investigate a wide range of heat generation. The stabilization of voltage observed in definite current range is discussed in terms of analysis of heat aspects of problem when a heat genemtion function and heat elimination they are regarded at helium temperuture. An electric temperature ordering of system is proposed as a factor responsible for voltage stabilization when the presence of more heated and less heated sections along conductor radius is connected with negativity of derivative of heat elimination function with respect to temperature between first and second boiling crisis.
关键词:
galvanomagnetic property
,
null
,
null
,
null
Journal of Alloys and Compounds
The magnetic properties of Pr2Co17-x Al-x and Y2Co17-xAlx compounds with 0 less than or equal to x less than or equal to 4 were studied by means of magnetic measurements. These measurements have shown that increasing Al concentration leads to a sign reversal of the magnetocrystalline Co-sublattice anisotropy from easy-plane anisotropy for low Al concentration to easy-axis anisotropy for higher Al concentration. In the Pr2Co17-xAlx compounds, the competition between the Pr-and Co-sublattice anisotropies leads to spin-reorientation transitions at temperatures that decrease strongly with increasing Al concentration. There is an almost linear decrease of the Curie temperature with Al concentration. Also the saturation moments at 5 K decrease strongly with Al concentration although this decrease is less strong in Pr2Co17-xAlx than in Y2Co17-xAlx. (C) 1997 Elsevier Science S.A.
关键词:
Co-rich rare earth compounds;R2Co17-xAlx;magnetic properties;spin;reorientation transitions
Journal of Alloys and Compounds
A study of the microstructure of the rapidly solidified Sm2Fe17N3-x alloy was carried out using transmission electron microscopy. A new hexagonal Sm2Fe17 phase, with space group P6(3)/mmc and lattice parameters a = 0.854 and c = 0.828 nm, was found. This hexagonal phase is metastable and can only be formed during rapid solidification. The high resolution image also identified many 2:17H domains inside the 2:17R phase. Large-angle trigrain boundaries with a 120-degrees rotation relationship between any two c axes were often formed in the alloy.
关键词:
陈京兰
,
孟丽琴
,
赵德乾
,
高书侠
,
杜江
,
吴光恒
人工晶体学报
doi:10.3969/j.issn.1000-985X.2001.02.016
利用磁悬浮冷坩埚提拉法技术生长了Tb2Fe17和Tb2(Fe,Si)17的单晶，并用差热分析等方法研究了材料的相图。研究结果表明：Tb2Fe17的相关系并非以往报道的包晶反应，而是同成分熔化。本文还给出了Tb2Fe17化合物附近的新相图。采用优化后的生长条件，获得了缺陷较少的Tb2Fe17和Tb2(Fe,Si)17高质量单晶。分析了Si替代对于化合物结构的影响。测量了Tb2Fe17单晶样品的基本磁性。从材料的一级磁化过程的测量可以看出，在理想配比条件下最容易获得缺陷密度低的单晶样品。这种磁性测量方法为了解单晶的完整性提供了一个有效的间接观察方法。
关键词:
Tb2Fe17
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Tb2(Fe,Si)17
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提拉法单晶生长
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相图
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磁性测量
赵静
,
朱祥伟
,
徐挺
,
尹大强
环境化学
doi:10.7524/j.issn.0254-6108.2015.07.2015020403
利用模式动物斑马鱼(Danio rerio)的运动行为实验,评价了在光照-黑暗周期刺激下BDE17(2,2’,4-tribromodiphenyl ether)和4’-OH-BDE17(4’-Hydroxy-2,2’,4-tribromodiphenyl ether)暴露对幼鱼运动行为效应,并利用分子对接技术和荧光素酶报告基因实验探讨了这两种化合物与斑马鱼视黄酸受体的相互作用关系,试图揭示运动行为效应的机制.BDE17暴露没有改变斑马鱼幼鱼的运动行为,而50 μg·L-1 4’-OH-BDE17暴露却造成斑马鱼幼鱼在光照和黑暗条件下均出现运动活跃现象.分子对接结果表明,BDE17和4'-OH-BDE17与斑马鱼视黄酸受体的结合能力都不如视黄酸(Retinoic acid,RA)强.荧光素酶报告基因实验结果表明,与对照组相比,50 μg·L-1 4’-OH-BDE17暴露组荧光素酶活性均显著增加(P＜0.05);而BDE17暴露组荧光素酶活性则无显著性差异.这表明4’-OH-BDE17通过直接与视黄酸受体(Retinoic acid receptors,RARs)结合来诱导视黄酸受体转录活性,而BDE17则不能直接与视黄酸受体发生相互作用.本研究结果表明4’-OH-BDE17暴露可能通过诱导视黄酸受体转录活性,干扰视黄酸动态平衡,造成神经系统发育损伤,进而改变斑马鱼幼鱼的运动行为,而BDE17暴露则不能.
关键词:
多溴联苯醚
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斑马鱼
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神经行为毒性
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视黄酸受体
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报告基因
,
分子对接
Journal of Applied Physics
Crystal-structure studies on Tm2Fe17-xGax (x = O, 1, 2, 3, 4, 5, 6, 7, and 8) compounds have shown that the prepared samples are single phase with the 2:17-type structure. Both the unit-cell volume and the saturation magnetization at 1.5 K decrease linearly with increasing Ga content. The Curie temperature is found to increase with increasing x; it goes through a maximum value of 485 K at about x = 3 to lower values and then it rises again. The Tm2Fe17-xGax compounds exhibit a spin-reorientaiton transition at low temperature. X-ray diffraction measurements on magnetically aligned Tm2Fe17-xGax powders show that the compounds with x less than or equal to 6 have the easy-plane type of magnetic anisotropy, whereas the compounds with x less than or equal to 7 exhibit the easy c-axis type of magnetic anisotropy at room temperature. (C) 1997 American Institute of Physics.
关键词:
neutron-diffraction;solid-solutions;magnetocrystalline anisotropy;substitution
Physica B-Condensed Matter
The magnetic properties of Tb2Co17-xAlx compounds with 0 less than or equal to x less than or equal to 4 were studied by means of magnetic measurements. There is a strong decrease of the saturation moment and the Curie temperature with AI concentration. In a previous investigation, it was shown that increasing AI concentration in R(2)Co(17-x)AI(x) compounds leads to a sign reversal of the magnetocrystalline Co-sublattice anisotropy from easy-plane anisotropy for low AI concentration to easy-axis anisotropy for higher AI concentration. In the Tb(2)Co(17-x)AI(x) compounds, the competition between the planar Tb-and easy-axis Co-sublattice anisotropy does not lead to spin-reorientation transitions because the Tb-sublattice anisotropy dominates at all temperatures. The occurrence of spin reorientations in R(2)Co(17-x)AI(x) compounds is discussed in terms of a simple model description.
关键词:
magnetism;magnetic anisotropy;spin reorientation;Tb-2(Co,Al)(17);intermetallic compounds
Journal of Applied Physics
The temperature dependence of the anisotropy field of Sm2Fe17C(x) and Tm2Fe17C(x) has been determined over the entire uniaxial ferro- or ferrimagnetic temperature range using the singularity point detection technique. The temperature dependence of the ac initial susceptibility was measured on these two systems from 4.2 to 300 K. The Curie temperature, lattice constants, spin-reorientation temperature (of Tm2Fe17C(x)) and the magnetic anisotropy field are increasing with increasing carbon concentration. A "magnetic-phase-like transition" is observed in Sm2Fe17C(x) for x < 0.7 at low temperatures, which is proved not to be a spin reorientation. Additionally, the transition temperature increases systematically with increasing carbon concentration. However, the nature of this transition is not yet well understood.
关键词:
magnetic-properties;earth
