M. Vergnat
,
M.Gerl+
,
Laboratoire de Métallurgie Physique et Science des Maériaux (U.R.A.au C.N.R.S.No. 155)
,
Universite de Nancy 1
,
France
材料科学技术（英文）
Amorphous Si_(1-x)Sn_x alloys have been prepared by co-evaporation onto substrates maintained at liquid nitrogen temperature. Their atomic structure is investigated using density measurements, scanning high-energy electron diffraction and Mossbauer spectroscopy. The optical and electrical properties are reported. Then, a method to hydrogenate the films during the evaporation process is described and applied to the preparation of amorphous semiconductors from pure silicon to pure tin. Finally, multilayers of type Si / Si:H / ... or Si:H / Si:D / ... are studied. The modulation of hydrogen is shown by low-angle neutron scattering and measurements of hydrogen diffusivity are presented.
关键词:
amorphous alloy
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null
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null
YANG Jilian ZHANC Baisheng DINC Yongfan China Institute of Atomic Engergy
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Beijing
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ChinaYANG Yingchang ZHANG Xiaodong Peking University
,
Beijing
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ChinaPAN Shuming General Research Institute for Non-Ferrous Metals
,
Beijing
,
China associate professor
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P.O.Box 275
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Branch No.30
,
Beijing 102413
,
China
金属学报(英文版)
The N occupying sites and magnetic structures in R_2Fe_(17)N_x(R=Y,Dy,Nd)are de- termined by neutron diffraction.The effects of the site occupation of N on magnetic properties are discussed primarily.
关键词:
neutron diffraction
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null
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null
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null
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null
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null
朱良
,
王晶
,
李晓慧
,
锁红波
,
张亦良
材料研究学报
针对应力比对疲劳寿命影响的问题,以TC18钛合金堆焊成形(利用多层堆焊的方法制备)试样为研究对象,进行了3种应力比(R=0.5、R=0.06、R=-1)的疲劳实验,得出相应的疲劳极限,应用"应力幅值寿命模型"和"三参数寿命模型"得到6条S-N曲线.根据裂纹扩展速率与疲劳寿命的积分关系,以两种疲劳寿命数学模型为基础,系统地研究了应力比(R)与疲劳寿命曲线(S-N)的关系,提出了考虑应力比的疲劳寿命(R-S-N)数学模型.根据本文提出的修正公式,建立了适用TC18钛合金堆焊成形材料的两种R-S-N数学模型,结果表明:用应力幅值寿命模型可对中等疲劳寿命区进行准确的预测,而三参数寿命模型更适合中长寿命区域的预测.提出的两种R-S-N数学模型与实验值吻合良好,并可在工程上预测任意应力比下的疲劳寿命曲线.
关键词:
材料科学基础学科
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应力比
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疲劳寿命
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疲劳极限
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R-S-N数学模型
Solid State Communications
Samples with composition R2Fe14M3 (M = Ga and Si; R = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) have been prepared by are-melting. Crystal-structure studies have shown that the prepared samples are single phase with the rhombohedral Th2Zn17 and/or the hexagonal Th2Ni17 structure. Substitution of Ga for Fe in R2Fe17 leads to an increase of the unit-cell volume, whereas Si substitution reduces the unit-cell volume. The Curie temperatures of the R2Fe14Ga3 and R2Fe14Si3 compounds are much larger than those of the corresponding R2Fe17 compounds. The Fe moment decreases upon Ga or Si substitution. The compounds R2Fe14Ga3 and R2Fe14Si3 With R = Er and Tm exhibit a spin-reorientation transition at low temperature. (C) 1997 Elsevier Science Ltd.
关键词:
neutron-diffraction;solid-solutions;substitution;anisotropy;nd2fe17
王德发
,
宋雅茹
,
胡玉萍
,
杨亦平
,
侯冬岩
色谱
doi:10.3321/j.issn:1000-8713.2003.04.027
利用卵类粘蛋白手性固定相高效液相色谱法直接拆分了S,S-和R,R-N-对甲基苯磺酰基-1,2-二苯基乙二胺(TsDPEN).研究了流动相中有机调节剂的种类和含量、缓冲溶液的酸度、盐浓度和流速等色谱条件对拆分结果的影响.结果表明,在25 ℃时,采用0.02 mol/L的磷酸二氢钾缓冲溶液(pH 4.56)(含20%(体积分数)乙腈)作流动相,流速0.4 mL/min,能得到最佳的基线分离.分离度和选择因子分别为2.67和2.23,流出时间在10 min之内.方法简单、快速.
关键词:
高效液相色谱
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卵类粘蛋白柱
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N-对甲基苯磺酰基-1,2-二苯基乙二胺
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对映体分离
杨继廉
,
张百生
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丁永凡
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杨应昌
,
张晓东
,
潘树明
金属学报
用中子衍射法测定了R_2Fe_(17)N_x(R=Y,Dy,Nd)中N的占位及磁结构,初步讨论了N的占位对磁性能的影响
关键词:
中子衍射
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Curie temperature
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permanent magnet
张颖
,
何茂刚
,
刘洋
工程热物理学报
改进了倾斜管式黏度测量实验系统,使其能够适用于非共沸物质饱和液相黏度的测量.对制冷剂 R22的替代物质一近共沸二元混合制冷剂R410A和非共沸三元混合制冷剂R407C的饱和液相运动黏度进行了测量,实验温度范围为256.15～336.15 K.同时,依据实验数据建立了制冷剂R410A和R407C饱和液相运动黏度与温度的关联式.
关键词:
运动黏度
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R410A
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R407C
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实验测量
Communications in Theoretical Physics
By means of both a theory for pressure-induced shifts (PS) of energy spectra and a theory for shifts of energy spectra due to electron-phonon interaction (EPI), the 'pure electronic' PS and the PS due to EPI of R-1 line, R-2 line, and U band of GSGG:Cr3+ at 300 K have been calculated, respectively. The calculated results are in good agreement with all the experimental data. Their physical origins have also been explained. It is found that the mixing-of degree \t(2)(2)(T-3(1))e(4)T(2)> and \t(2)(3) 2E> base-wavefunctions in the wavefunctions of R-1 level of GSGG:Cr3+ at 300 K is remarkable under normal pressure, and the mixing-degree rapidly decreases with increasing pressure. The change of the mixing-degree with pressure plays a key role not only for the 'pure electronic' PS of R-1 line and R-2 line but also the PS of R-1 line and R-2 line due to EPI. The pressure-dependent behaviors of the 'pure electronic' PS of R-1 line (or R-2 line) and the PS Of R-1 line (or R-2 line) due to EPI are quite different. It is the combined effect of them that gives rise to the total PS of R-1 line (or R-2 line). In the range of about 15 kbar similar to 45 kbar, the mergence and/or order-reversal between t(2)(2)(T-3(1))e(4)T(2) levels and t(2)(32)T(1) levels take place, which cause the fluctuation of the rate of PS for t(2)(2)(T-3(1))e(4)T(2) (or t(2)(3) T-2(1)) with pressure. At 300 K, both the temperature-dependent contribution to R-1 line (or R-2 line or U band) from EPI and the temperature-independent one are important.
关键词:
high-pressure effect;spin-orbit interaction;electron-phonon;interaction;d orbital;coupling between t(2)(2)(3T(1))e(4)T(2) and;t(2)(32)E;tunable laser crystal;theoretical calculations;temperature-dependence;thermal broadenings;garnet crystals;cr3+ ions;r-line;cr-3+;luminescence;ruby;spectroscopy
Journal of Applied Physics
The magnetic properties of R2Co14B1-xCx (x=0, 0.5 and R=Y, Sm) compounds have been studied by measuring the temperature dependence of the easy- and hard-magnetization curves on magnetically aligned samples between 1.5 and 300 K for Y2Co14(B,C) and at 4.2 K for Sm2Co14(B,C). The magnetic anisotropy of Y2Co14B increases due to the substitution of C for B, whereas the saturation magnetization decreases. Between 1.5 and 300 K, the anisotropy field of Y2Co14B0.5C0.5 increases about 2 T and the Co moment decreases about 0.05mu(B). The anisotropy field Of Sm2Co14B also increases upon C substitution and the saturation magnetization decreases slightly. The ac susceptibilities of both SM2Co14B and Sm2Co14B0.5C0.5 exhibit anomalies that may arise from a spin reorientation within the basal plane.
关键词:
nd2fe14b;exchange;nd2co14b;r2fe14b;field
Solid State Communications
Magnetic anisotropy fields at room temperature of ternary tetragonal compounds of R2Fe14C(R = Lu, Gd, Nd) and R2Fe14B(R = Gd, Nd) were determined by Singular-Point-Detection (SPD) technique. The magnetocrystalline anisotropies of the carbides were found to be larger than those of their corresponding borides, indicating that the outstanding permanent-magnetic properties may be obtained in the R2Fe14C-based alloys.
关键词:
