R. V. Safiullin
,
R.A. Vasin and F. U. Enikeev Institute for Metals Superplasticity Problems Khalturina
,
39
,
Ufa
,
450001
,
Russia
金属学报(英文版)
A method for determining the value of the strain rate sensitivity parameter m, of a thin sheet superplastic material, which is based on the results of constant gas pressure tests, has been developed in this paper. Unlike the conventional procedures the method involved provides the test conditions similar to those occurring during an industrial technological process. Such an approach enables one to estimate reliable the superplas- tic properties of the material under study. Theoretical analysis is based upon use of the standard equations of the membrane theory. The experimental investigations have been carried out for Ti-based alloy VT6 (Ti--6Al-4V). Theoretical predictions show satisfactory agreement with experimental data. The results obtained are compared with those measured by means of standard procedures (constant cross-head velocity experiments and load relaxation tests). It is shown that the use of specimens having reduced gage length (which is less than specimen's width) could lead to considerable errors in experimental estimation of the m value which, in its turn, leads to inaccurate calculating the technological parameters.
关键词:
superplasticity
,
null
,
null
,
null
材料科学技术（英文）
Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.
关键词:
model;films
Wei WANG
,
Lishi WEN
材料科学技术（英文）
Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction, for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.
关键词:
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
郑娜
,
陈忠靖
,
孙吉宁
,
刘廷进
,
陈金象
,
樊铁栓
原子核物理评论
为满足堆内或核爆中链式反应过程的燃耗值的计算需要,对裂变谱中子和14 MeV中子诱发~(238) U 裂变的短寿命产物核的累积产额进行了评价.评价利用了所有可利用的实验数据,经物理分析后,使用AVERAGE程序加权平均,用ZOTT程序进行同时评价,给出了所要求能点的唯一最佳推荐数据,并将评价结果与ENDF/B-VⅡ,JEF-2.2,JENDL-3.2和CENDL-2的推荐数据进行了比较.评价结果将用于CENDL-2的更新与升级.
关键词:
~(238)U(n,f)反应
,
累积产额
,
裂变产物的评价
倪卓
,
李丹
,
钟玉莲
,
刘丽双
,
陈展明
材料导报
采用十八胺对永固红F5R进行化学修饰,以Span-80为稳定剂,四氯乙烯为分散介质,制备了分散性和稳定性良好的电泳液.以此电泳液为囊芯,脲甲醛树脂为壁材,制备了一种红色电子墨水微胶囊,研究了投料比、合成温度、酸化时间和搅拌速度等对合成微胶囊的影响.结果表明,合成的微胶囊形貌呈规则球形,表面光滑,囊壁结构致密,强度较好,包覆率达到82%,囊芯含量达到76%.永固红F5R电泳液微胶囊具有明显的电场响应行为,可以作为柔板显示器的功能材料.
关键词:
电子墨水
,
微胶囊
,
永固红F5R
,
电场响应
Deheng ZHANG
,
Dejun ZHANG
,
Qingpu WANG
,
Tianlin YANG
材料科学技术（英文）
This paper presents the substrate temperature dependence of opto-electrical properties for transparent conducting Al-doped ZnO films prepared on polyisocyanate (PI) substrates by r.f. sputtering. Polycrystalline ZnO:Al films with good adherence to the substrates having a (002) preferred orientation have been obtained with resistivities in the range from 4.1 x 10(-3) to 5.3 x 10(-4) Ohm .cm, carrier densities more than 2.6 x 10(20) cm(-3) and Hall mobilities between 5.78 and 13.11 cm(2)/V/s for films. The average transmittance reaches 75% in the visible spectrum. The quality of obtained films depends on substrate temperature during film fabrication.
关键词:
