SVPWM变频调速系统中电流检测和矢量转换电路的设计

本文简介了空间矢量脉宽调制变频调速系统，针对该矢量控制系统中存在矢量坐标转换这一非线性环节和电流检测环节，研制了一种高精度的快速电流检测和矢量转换电路，此电路从属于系统主控制器。通过将次电路从主控制器分离出来的方法，为主控制器节省了有效的处理时间。     

基于MapObjects的全球矿产资源信息系统中投影坐标转换的实现

在介绍MapObjects及其常用的坐标系对象基础上,针对全球矿产资源信息系统多投影坐标系并存的特点,采用其他GIS软件辅助完成坐标系的转换,同时利用MapObjects已有的坐标系对象,实现了该软件的图层转换、查询检索等功能。     

Electrochemical studies of the inhibition of the cathodic delamination of organically coated galvanised steel by thin conversion films

Scanning Kelvin Probe (SKP) measurements of thin amorphous conversion film coated galvanised steel in combination with current density-potential curves and electrochemical impedance spectroscopy (EIS) were performed with the aim to improve the understanding of electrode potentials at the coating/metal interface and their influence on corrosive de-adhesion. The thin hybrid conversion films contained Zn-phosphates, titanates and also complexing organic compounds and led to an inhibition of the cathodic oxygen reduction and anodic zinc dissolution. In the polymer coated area the conversion film leads to a cathodic shift of the potential as measured by means of the SKP. This cathodic potential shift is explained by the substitution of the n-semiconducting Zn-oxide with an insulating inorganic layer. When the SKP detects the potential of freely corroding iron at a defect, where no protective coating layer is, the interfacial potential for the conversion film coated zinc layer is more negative than the defect potential. This leads to a diminished driving force for an oxygen reduction induced delamination process which is of relevance for the understanding of cut-edge corrosion.     

The influence on immersion time of titanium conversion coatings on electrogalvanized steel

The study aims to replace chromate treatments of electrogalvanized steels by immersing the electrogalvanized steel in a titanium trichloride (TiCl₃) bath. The influence of immersion time on surface morphology and corrosion resistance of the titanium conversion coatings was investigated. The titanium conversion coating prepared for 300 s immersion time with a uniform structure has the most excellent anticorrosive performance. Furthermore, the coating comprises a loose outer layer and a dense inner layer structure with a thickness of 150 nm. X-ray photoelectron spectroscope analysis shows that the coating consisted of Zn and Ti oxides and/or hydroxides.     

紫外光固化胶粘剂固化率的测定

介绍了一种用红外吸收光谱测定紫外光固化胶粘剂固化率的方法，并推导出估算固化率的公式。     

钼化合物在表面处理中的应用

归纳介绍了钼及其化合物的理化性能及其在腐蚀防护方面的应用。     

多相输电系统中的相变换电力变压器的探讨

概要介绍了多相输电系统的发展情况及其所具有的潜在优势，论述了几种相变换变压器的基本原理及接线方式。     

缅甸DAPEIN（I）水电站引水发电隧洞进水口高边坡稳定分析

采用极限平衡分析法对缅甸DAPEIN(Ⅰ)水电站工程引水隧洞进口高边坡进行稳定分析.稳定分析过程中提出的计算断面的选择、反演参数的选用,以及确保高边坡开挖稳定的一些措施等,可供类似工程借鉴和参考.     

Mesoporous Cr2O3 as negative electrode in lithium batteries: TEM study of the texture effect on the polymeric layer formation

Mesoporous single crystal (PSC) oxides have been reported as presenting higher electrochemical performances than bulk materials in lithium ion batteries operating via intercalation processes. Here, we extend this study to the electrochemical behaviour of mesoporous Cr₂O₃ versus Li⁺/Li⁰. We confirm that the Cr₂O₃ reacts towards Li through a conversion reaction mechanism leading, upon discharge, to the formation of large metallic chromium nanoparticles (10 nm); the latter are embedded into a Li₂O matrix together with, in this specific case, a copious amount of polymeric materials coming from electrolyte degradation, surrounding the particles, and filling the pores. During the following charge, re-oxidation of the nanoparticles occurs with the formation of CrO_1−x, with the main difference, as opposed to bulk Cr₂O₃ electrodes, being the preservation of the polymeric layer at the end of the charge. We believe the material mesoporosity, via capillary effects, to be at the origin of such a difference. These electrolyte degradation products are shown to help in maintaining the material mesoporosity for a great number of cycles; and interestingly they are not detrimental to the cell performance in terms of capacity retention while presenting great advantages in terms of charge transfer by reducing diffusion lengths, namely for Li⁺ ions. The positive attributes of mesoporous material-based electrodes noticed for insertion reactions can then be extended to conversion reaction electrodes as long as we can master their synthesis while controlling their mesoporosity through either soft or hard templating techniques.     

Thermodynamic investigation of methanol and dimethyl ether synthesis from CO2 Hydrogenation

The thermodynamics involved in the catalytic hydrogenation of CO₂ have been examined extensively. By assuming that methanol and dimethyl ether (DME) are the main products, two reaction systems each consisting of two pararell reactions were analyzed and compared in terms of the equilibrium yield and selectivity of the useful products, methanol and DME. The calculation results demonstrated that the production of DME allows much higher oxygenate yield and selectivity than that of methanol.