1，1'-二乙酰基二茂铁合成工艺研究

以三氯化铝为催化剂，醋酐为酰化剂，在二氯甲烷中对二茂铁的双酰化进行了研究，讨论了反应温度、催化剂用量、物料摩尔比、投料方式、反应时间对合成工艺的影响，得到了产率较高、反应时间较短的合成l，1'- 二乙酰基二茂铁的工艺条件。     

Neutron diffraction study of the oxychloride layered perovskite, (CuCl)LaNb2O7

The structure of the oxychloride layered perovskite, (CuCl)LaNb₂O₇, has been examined by neutron diffraction. Rietveld refinement of room temperature neutron TOF data, while consistent with the previous X-ray study, allows for an improved modeling of the structure. The structure consists of double perovskite layers (LaNb₂O₇) separated by copper chloride layers. The copper is octahedrally coordinated, bridging between apical oxygens from the perovskite layer and surrounded by four chlorines in the CuCl plane; this gives rise to edge-sharing CuO₂Cl₄ octahedra. The chlorines within the CuCl plane were found to move off the ideal (0, 0, 1/2) position to a more general position, (x, 0, 1/2). This disorder leads to a combination of four short and two long distances, common to the Jahn-Teller distorted environments for d⁹ copper. Structural details are discussed with respect to their influence on the chlorine disorder.     

A semi-analytical simulation strategy and its application to warpage of autoclave-processed CFRP parts

The manufacturing of composite structures is accompanied by fabrication induced deformations. Those deformations are undesirable and lead to transgression of geometric tolerances in the finished parts. In order to get the part within aspired dimensional tolerances, geometrical compensation of the tool is necessary. This often iterative conducted tooling-rework is commonly time consuming and costly. This paper presents an shell element based. semi-analytical simulation approach focusing on warpage deformations due to tool part interaction, in order to account for manufacturing induced deformations within the tool design process. Deviation measurements on test specimen level serve as inputs for the calculation of equivalent coefficients of thermal expansion according to the proposed analytical model. Thus, ‘warpage properties’ of different prepreg – tool–material combinations are determined. The use and the practicability of the developed approach is demonstrated by means of the calculation of a warpage compensated tool surface.     

Current Status in Layered Ternary Carbide Ti3SiC2, a Review

This article provides a review of current research activities that concentrate on Ti3SiC2. We begin with an overview of the crystal and electronic structures, which are the basis to understand this material. Followings are the synthetic strategies that have been exploited to achieve, and the formation mechanism of Ti3SiC2. Then we devote much attentions to the mechanical properties and oxidation/hot corrosion behaviors of Ti3SiC2 as well as some advances achieved recently. At the end of this paper, we elaborate on some new discoveries in the Ti3SiC2 system, and also give a brief discussion focused on the "microstructure -property" relationship.     

Electrocatalysis of gold nanoparticles/layered double hydroxides nanocomposites toward methanol electro-oxidation in alkaline medium

A nanocomposite based on layered double hydroxides (LDHs) and gold nanoparticles (AuNPs) was prepared via hydrothermal treatment followed by a reduction procedure. The AuNPs were obtained in Mg-Al LDHs, and they maintained good stability. The electrocatalytic activities of AuNPs/LDH-modified glassy carbon electrodes for methanol oxidation in alkaline medium were investigated in detail. Under the same conditions, the modified electrode exhibited higher electrocatalytic activity than both the pure AuNPs-modified electrode and LDH-modified electrode. The role of the AuNPs and LDHs in this composite system was explored by cyclic voltammetry and chronoamperometry, respectively. Further studies demonstrated that the promoting effect of LDHs could be due to its strong adsorption and partly to the discharge of OH⁻ during methanol oxidation. This work indicates that LDHs is expected to be a good supporting material in the development of methanol anode catalysts.     

Ultradispersed particles in heavy oil: Part I, preparation and stabilization of iron oxide/hydroxide

In this study, ultradispersed colloidal particles of iron oxide/hydroxide were prepared in-situ in heavy oil matrices adopting (w/o) microemulsion approach for nanoparticle preparation detailed in our previous work [1-3]. The effect of composition of heavy oil on the stable concentration of colloidal particles, particle uptake, was investigated. The following trends in particle uptake were common between the (w/o) microemulsions and the heavy oil matrices. An optimum water content was found for which a maximum particle uptake was attained. Particle uptake increased as the content of vacuum residue, VR, and precursor salt concentration increased. Vacuum residue contributes high asphaltene content, which acts as a surface active agent. The iron oxide/hydroxide particles had been recently shown to effectively remove H₂S_(g) from oil phase [4]. H₂S_(g) is a hazardous by-product of heavy oil recovering and upgrading which should be removed as soon as it forms. Results pertaining to H₂S_(g) removal from heavy oil employing ultradispersed particles are communicated in Part II of this study.     

Thermally assisted in-line methylation and gas chromatography with statistical data analysis for determination of fatty acid distribution and fingerprinting of plant seeds and oils

Received: 11 October 1999 / Revised version: 7 December 1999     

WSA-DC——下一代高浓度高转化率WSA工艺

介绍了托普索公司新开发的WSA-DC工艺,详述其流程、优点、性能、消耗和生产数据.WSA-DC工艺是一个两次冷凝工艺,它结合了WSA工艺与两转两吸工艺的优点,通过对中间冷凝器的设计改进和仔细控制气体中的H2O/SO2比率,可以用ψ(SO2)等于或高于13%的原料气生产w(H2SO4)为99%的硫酸.以1套540t/d硫磺制酸装置为例,对WSA-DC工艺和传统干法两转两吸工艺进行了技术经济比较.     

红水河流域大型取水泵房的型式选择

红水河干流河槽狭窄、切割较深,河床及岸坡多为基岩出露,滩多水急,设计洪水位与设计枯水位差值悬殊.采用直流供水系统的火力发电厂需要从河流取大量循环冷却水,按发电机组容量和不同时期设计了潜没式圆形、竖井式圆形、露天式矩形三种型式的大型取水泵房.文章对这些取水泵房的设计进行总结和分析,为地表水取水泵房的设计提供帮助和启示.     

Exponential Basis Functions in solution of laminated structures

In this paper a new method for solution of static two-dimensional laminates has been proposed. A series of Exponential Basis Functions (EBFs) have been used to satisfy the governing equations within each layer. Compatibility and equilibrium conditions at the interfaces of the layers, with isotropic or orthotropic properties, are rigorously satisfied through defining a characteristic problem. The solution of such a characteristic problem yields to a set of spectral basis functions through which one may obtain a clear insight to the modes governing the displacement field. For further use, we present simplified relations for single-layer and two-layer laminates. The boundary conditions at the ends of the laminate are satisfied by a suitable discrete transformation in a collocation style. With such an approach one can solve problems with variety of end conditions. Excellent agreement is observed between the results of this work and some benchmark problems. Some more problems are solved as new benchmarks for further studies.