硒的分析方法研究

硒是一种分散的稀有元素，它在电子工业，医疗等部门有广泛的用途和诱人的发展前景。本文介绍了一些硒的定性和定量分析方法。     

Bi2223带材的临界电流及交流损耗研究

测量了77K温度下不同基体材料和不同芯数带材的临界电流和交流损耗.分析了弯曲应变对它们的影响.结果表明单芯样品的不可逆应变小于0.15%,而多芯样品的不可逆应变在01%到03%之间,多芯导体的机械性能比单芯导体的好,增加芯数可以提高机械性能,金属包套材料对超导芯起到了增强的作用,它防止了超导芯中裂纹的进一步传播.自场损耗随外加应变的增加而增加,这种大幅度的增加与应变使带材的临界电流急剧减小直接相关 关键词： 高温超导体 临界电流 交流损耗     

Sharp Estimates in Bergman and Besov Spaces on Bounded Symmetric Domains

Sharp estimates of the point-evaluation functional in weighted Bergman spaces L ^p _a (Ω, dν _α) and for the point-evaluation derivalive functional in Besov spaces B ^p (Ω) are obtained for bounded symmetric domains Ω in ℂ ⁿ . Received October 25, 1999, Accepted December 6, 2000     

catena‐Poly[[[bis(μ‐4,5‐dihydrothiazole‐2‐thiolato)‐tetrahedro‐tetracopper(I)]‐di‐μ‐4,5‐dihydrothiazole‐2‐thiolato] dihydrate]

The title compound, {[Cu₄(C₃H₄NS₂)₄]·2H₂O}_n, was produced by diffusing a solution of 2‐mercapto­thia­zoline in tetra­hydro­furan into a solution of CuCl in CH₃CN at room temperature. The structure is characterized by self‐assembled one‐dimensional chains that are condensed from butterfly‐like [Cu(C₃H₄NS₂)]₄ tetrameric units via double S‐bridging at opposite ends. The Cu—Cu distances within the Cu₄ butterfly cluster are in the range 2.7103 (10)–2.9764 (10) Å, while the shortest Cu?Cu intercluster distance is 3.468 (1) Å, much longer than the sum of the van der Waals radii.     

Study on size-dependent optical property of 4,4′-dibromobiphenyl nanocrystals

4,4^′-dibromobiphenyl nanocrystals with different sizes in the range from 20 nm to 300 nm were prepared by the reprecipitation method. It was found that their absorption peaks experienced a red shift while the size of the nanocrystals increased. Through analyzing these spectra of the nanocrystals with different sizes, it is suggested that this size-dependent optical property is contributed by two factors, the size effect and the J-aggregate formation. Received: 28 August 2000 / Accepted: 2 March 2001 / Published online: 23 May 2001     

高阶PMD统计特性研究

讨论了三阶偏振模色散(PMD)的统计特性及其对于高阶PMD补偿系统的影响.数值模拟结果表明,随着即时差分群时延(DGD)的增加,二阶PMD单位矢量旋转速率的统计覆盖范围的变化趋势与主偏振态(PSP)旋转斜率的相应变化正好相反.此外,随着即时DGD的增加,二阶PMD模值的统计覆盖范围不断增加,使得高速光通信系统中高阶PMD补偿的实现将更加困难.     

线性矩阵哈密顿系统的振动性

研究了线性矩阵 Hamilton系统X′=A( t) X + B( t) YY′=C( t) X -A*( t) Y　　 t≥ 0的振动性 .其中 A( t) ,B( t) ,C( t) ,X,Y为实 n× n矩阵值函数 ,B,C为对称矩阵 ,B正定 .借助于正线性泛函 ,采用加权平均法 ,得到了该系统的非平凡预备解的振动性 .这些结果推广、改进了许多已知的结果     

从强子动力学模型看高温条件下核物质的新相

从QHD-Ⅱ模型的拉氏量出发,在有限温度场论的框架下,引入核子有效质量和有效化学势,给出了热力学势的平均场结果,分析了状态方程,发现在高温区核物质存在一个新的相变,最后给出了相图.     

4-(2-吡啶偶氮)-间苯二酚光度法测定煤灰中钒

在 0 .6 mol· L-1的硫酸介质中 ,钒 - PAR-羟胺生成红色络合物 ,最大吸收波长为 5 5 0 nm,摩尔吸光系数ε=1.91× 10 4L· mol-1· cm-1,钒含量在 0— 80μg/ 2 5 m L范围内符合比耳定律。本方法灵敏、简便 ,用于测定煤灰中的钒 ,结果满意     

无源红外方位标研究

提出在现有条件下利用激光实现无源红外方位标的思路，并通过详细计算与分析，论述了无源红外方位标的可行性。