Journal of Physics and Chemistry of Solids
The tetragonal distortion for the tetragonal V2+-V-M center in KBr:V2+ crystal is estimated by analyzing its EPR data from two theoretical models, one is the two spin-orbit (S.O.) parameter model where the contributions to EPR parameters from both the S.O. coupling of the central metal ion and that of the ligands are considered and another is the conventional one-S.O.-parameter model where only the contribution from the S.O. coupling of the central metal ion is included. The result from the two-S.O.-parameter model is more than ten times that of the one-S.O.-parameter model. The reasonableness of the former is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.
关键词:
inorganic compounds;crystal fields;defects;electron paramagnetic;resonance (EPR);epr parameters;transition;ions
Journal of the American Ceramic Society
A dense V(2)AlC ceramic was synthesized by an in situ reaction/hot pressing method using V, Al, and C powders as starting materials. The reaction path was investigated. It was found that V(2)AlC was produced by a reaction between Al(8)V(5) and C. Single -phase V(2)AlC could be prepared using the optimized molar ratio of V:Al:C=2:1.2:0.9. The grain sizes of as-prepared V(2)AlC samples were temperature dependent. On increasing the temperature from 1400 degrees to 1700 degrees C, the mean grain size of V(2)AlC increased from 49 mu m in length and 19 mu m in width to 405 mu m in length and 106 mu m in width. The V(2)AlC sample sintered at 1500 degrees C exhibited the highest flexural strength of 289 MPa and a fracture toughness of 5.7 MPa.m(1/2), while the V(2)AlC sample prepared at 1400 degrees C showed the highest compressive strength of 742 MPa. The sample sintered at 1700 degrees C possessed the highest damage tolerance. Additionally, V(2)AlC could retain a high degree of Young's modulus up to 1200 degrees C. Below 800 degrees C, V(2)AlC showed excellent thermal shock resistance.
关键词:
liquid reaction synthesis;thermal-shock behavior;layered ti3sic2;pressing method;bulk cr2alc;ceramics;ti3alc2;phases;ti;damage
林枫凉
,
薛立新
,
朱斌
,
王大志
,
俞文海
材料研究学报
<正> 蒙脱石是一种丰富廉价的天然矿物,具有开放的层状结构和良好的离子导电性,已被用于固态电池。本文使用蒙脱石为固体电解质研究了可充电的Zn/V_2O_5固态电池的性能。Zn/V_2O_5固态电池的开路电压随着V_2O_5复合阴极中V_2O_5含量的减少而下降,其变
关键词:
吴广明
,
吴永刚
,
倪星元
,
周箴
,
张慧琴
,
金哲民
,
吴翔
无机材料学报
本文采用真空蒸发制备了V2O5薄膜，用电化学方法从Li离子电解质中向V2O5薄膜注入Li离子.研究了V2O5薄膜中Li离于储存特性、注入／退出可逆性以及电荷注入对其光学性能的影响．实验结果表明，V2O5薄膜具有较好的Li离子储存特性和注入／退出可逆性，Li离子的注入量受到膜中V5+的含量以及锂离子可占据的总位置数限制，而且离子注入后V2O5薄膜的光学性能变化较小．
关键词:
薄膜
,
null
,
null
,
null
杨绍利
,
徐楚韶
,
胡再勇
,
陈光碧
钢铁钒钛
doi:10.3969/j.issn.1004-7638.2001.04.006
用攀钢工业V2O5为原料,采用无机溶胶-凝胶法制备出透明、导电的V2O5薄膜,并实测了电阻率.实验制作的V2O5薄膜电阻率对温度、湿度比较敏感,是一种很好的湿敏材料.薄膜烘干后电阻率减小,吸收水分后电阻率又增大.增加薄膜厚度则其电阻率增大.
关键词:
溶胶-凝胶法
,
V2O5
,
薄膜
,
电阻率
Journal of Physics and Chemistry of Solids
In this paper, the high-order perturbation formulae of zero-field splitting D, E and g factors g(x), g(y), and g(z) for d(3) ions in rhombic symmetry are established by using a two spin-orbit (S.O.) parameter model in which the contributions due to both the S.O. coupling of the central d(3) ions and that of the ligands are considered. Based on these formulae, the local structural parameters of the rhombic defect centers V2+-V-M (i.e, the V2+ ion and a host metal ion vacancy V-M) in MCl:V2+ (M = Li, Na) crystals are estimated by calculating their EPR parameters. The results are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.
关键词:
inorganic compounds;crystal fields;defects;electron paramagnetic;resonance (EPR);ions
Physica Status Solidi B-Basic Research
The high-order perturbation formulas of zero-field splitting D and gyromagnetic factors g(parallel to) and g(perpendicular to) for 3d(3) ions in tetragonal symmetry are established by using a two-spin-orbit(SO)-parameter model where the contributions to these EPR parameters from both the SO coupling of the central 3d(3) ions and that of the ligands are considered. From these formulas, the local structural parameters for the tetragonal V2+-V-M centers in MCl:V2+ (M = Na, K, Rb) crystals are estimated from the EPR data. The results are compared with those obtained from the conventional one-SO-parameter model where only the contribution of the SO coupling of central 3d(3) ions is included. The reasonableness of the results based on the two-SO-parameter model is discussed.
关键词:
ions
Communications in Theoretical Physics
The mistakes in Ref. [3] are pointed out. Some important problems are discussed, and the correct ideas, calculations and results are given. The R-line thermal shift of MgO:V2+ at normal pressure is the algebraic sum of the contribution from electron-phonon interaction and the contribution from thermal expansion. The latter can be calculated by using the thermal expansion coefficient and the pressure-induced shift.
关键词:
R-line thermal shift of MgO : V2+;pressure;temperature
