Synthesis and crystal structure of the octahedral cluster complex [Th(DMSO)8Cl][Re6Se7Cl7]

A cluster complex of the composition [Th(DMSO)₈Cl][Re₆Se₇Cl₇] has been obtained by interaction of ThCl₄ solution in DMSO with a water solution of K₃[Re₆Se₇Cl₇] and KCl. The compound crystallizes in the rhombic space group Pbcm with unit cell parameters a = 12.262(2) Å, b = 19.653(6) Å, c = 23.603(6) Å, V = 5688(2) ų, Z = 4, d _calc = 3.282 g/cm³. The structure is built from centrosymmetric cluster anions [Re₆Se₇Cl₇]^3? and complex cations [Th(DMSO)₈Cl]³⁺ possessing mirror-plane symmetry, half of the DMSO ligands being doubly disordered.     

Internal standardization for the determination of cadmium,cobalt, chromium and manganese in saline produced water from petroleum industry by inductively coupled plasma optical emission spectrometry after cloud point extraction

In the present paper a procedure is proposed for the determination of traces of Cd, Co, Mn and Cr in petroleum industry produced water by inductively coupled plasma optical emission spectrometry. The procedure is based on cloud point extraction of these metals, as their dithizonate complexes, into the surfactant-rich phase of octylphenoxypolyethoxyethanol surfactant (Triton X-114). Extractions were carried out in solutions with salinities between 10‰ and 70‰. Since residual salinity in the surfactant-rich phase caused differences in its transport to the plasma, yttrium was used as an internal standard to correct for this effect. The simultaneous metal extraction procedure was optimized by response surface methodology using a Doehlert design and desirability function. Enhancement factors of 21, 21, 9 and 19, along with limits of quantification of 0.093, 0.20, 0.73 and 1.2 μg L^− 1, and precision expressed as relative standard deviation (n = 8, 20.0 μg L^− 1) of 5.8, 1.2, 1.7 and 5.7% were obtained for Cd, Co, Mn and Cr, respectively. The accuracy was evaluated by spike recovery tests on the high salinity water samples with salinity of 40 and 63‰.     

圆形池壁滑模提升系统设计与施工

本阐述了郑州污水处理厂等直径钢筋混凝土消化池，采用滑升模板施工，连续浇筑混凝土提高工效，经过满水和闭气试验，符合设计要求，保证工程质量．取得较好的结果。     

干电池供电式电子标准电池的设计

标准电池是度量电源电动势的标准仪器．利用RC4191和MC1403精密的低压稳压特性，设计一款电子稳压式的标准电池，既可克服传统汞镉标准电池的缺点，又能保证相同精度的实验性能要求．     

Pseudoaffinity, de Boor algorithm, and blossoms

In order to ensure existence of a de Boor algorithm (hence of a B-spline basis) in a given spline space with (n+1)-dimensional sections, it is important to be able to generate each spline by restriction to the diagonal of a symmetric function of n variables supposed to be pseudoaffine w.r. to each variable. We proved that a way to obtain these three properties (symmetry, n-pseudoaffinity, diagonal property) is to suppose the existence of blossoms on the set of admissible n-tuples, given that blossoms are defined in a geometric way by means of intersections of osculating flats. In the present paper, we examine the converse: do symmetry, n-pseudoaffinity, and diagonal property imply existence of blossoms?     

变速齿轮传动系统最佳轴向结构布局智能设计的推理机制

本文通过对变速齿轮传动系统轴向结构布局设计规律的研究,提出了一种适合于该类问题的知识表达方式,将改进后的带有启发函数的最佳优先搜索方法引入到该问题的求解中,使得含有多重搜索空间以及带有一定约束的设计问题统一在同一搜索策略下。根据本文提出的方法,用PROLOG语言建造的推理机,通过对实际问题的考证,证明该方法在解决传动结构自动设计上是行之有效的,并且在推理机制上成功地体现了设计过程中反复设计与优化设计的功能特征.     

CSDS法及其在磁悬浮支承优化设计中的应用

本文介绍了一种非线性规划问题的算法、——CSDS法,给出了其数学模型和在微机上运行的FORTRAN实用于程序,通过对磁悬浮支承定子最小重量的优化设计,说明了CSDS法是一种行之有效的优化设计算法。     

3000TEU巴拿马型集装箱船设计探讨

围绕一艘３０００ＴＥＵ巴拿马型集装箱船设计中提出的主尺度确定、船型和快速性、稳性和装载等若干问题进行探讨，给出了可供参考的解决问题的途径．     

单涂层吸波材料的优化设计及偏差研究

本文通过对单涂层吸波材料内电磁波传输损耗机理的细致研究，提出了单涂层吸波材料优化设计的两项原则。结合具体实例详细说明这两项原则的具体应用，最后讨论涂层电磁参量在偏离匹配条件的情况下，对涂层吸波性能影响的具体结果分析。图３．表１，参３。     

我国跨国经营的发展构想

本文在系统阐述当代跨国经营战略调整与发展趋势的基础上，简要剖析了现阶段我国企业跨国经营的主要问题，重点探讨了我国跨国企业发展战略的基本构想。