Kinetics and mechanism of carbothermic reduction of magnesia

The reaction between MgO and graphite powders under flowing argon atmosphere was studied using a dynamic thermogravimetric method. In the temperature range 293 to 1973 K, the effects of compacting pressure, magnesia/carbon ratio, heating rate, Ar carrier-gas flow rate, and CO-partial pressure were investigated. An experimentally determined reaction mechanism was proposed and discussed. The reduction process could be divided into two stages. The first stage includes the direct reaction between MgO and graphite particles and partial gas-solid reaction at relatively low temperature (below 1750 K). The overall reaction rate depends on the solid phase-boundary reaction between magnesia and carbon particles. The second stage is the gas-solid reaction between CO and MgO, which determines the overall reaction rate. The apparent activation energies of the two stages were estimated to be 208.29 and 374.13 kJ/mol, respectively.     

江苏复杂断块高含水单元改善水驱效果的技术对策

在分析高含水开发单元特点的基础上,针对该阶段剩余油的品位、分布和油水关系极为复杂、挖潜难度大的技术难点,提出了适合江苏复杂断块油田高含水开发单元改善水驱开发效果的思路和工作程序、技术对策,并在真武油田高含水开发单元进行了实际应用,取得了良好的效果.     

Preparation and Characterization of Carboxymethyl Chitosan and β-Cyclodextrin Microspheres by Spray Drying

Three kinds of carboxymethyl chitosan/β-cyclodextrin microspheres loaded with theophylline were prepared by spray drying intended for pulmonary delivery. Mucociliotoxicity, permeation rate, and drug release characteristics of the product were investigated. The microspheres obtained by spray drying were found to be spherical with smooth or wrinkled surfaces. The mean particle size was between 3.39 and 6.06 µm. The microspheres demonstrated high product yield (43.7-50.2%), high drug loading (13.7-38.1%), and high encapsulation efficiency (86.9-92.8%). FT-IR indicated that there were interactions of theophylline with carboxymethyl chitosan matrix. Further studies on mucociliotoxicity and permeation confirmed that microspheres had better adaptability and high permeation rate. In vitro drug release from the microspheres was not related to the drug/polymer ratios.     

Computer aided kinetic modeling with KMT and KME

The complexity of many chemical and refining reaction systems and the thus-derived tedious and time-consuming process of building the associated kinetic models have been major obstacles in the use of fundamental kinetics in the solution of chemical engineering problems. This review summarizes work aimed at removing theses obstacles. Our recent work that has led to the enhancement of the Kinetic Modeler's Toolbox (KMT) and the development of the Kinetic Model Editor (KME) presents an end-to-end solution to the kinetic modeling process, including automated feedstock modeling, reaction network construction, kinetic rate estimation, model programming, process system configurations, model customizations, compilations, model execution and results analysis.     

管道安装工程中管路及附件匹配性问题研究

在管道设备安装工程中，常出现到货管材与管路附件不匹配的问题，究其原因，主要是目前国内使用的管材与管路附件标准繁杂、兼容性不高所致。为此，文章从管材及管件、阀门、管路法兰三方面分析了现行国内外标准之间、国标与行标之间存在的差异，并提出防止管材与管路附件不匹配的措施。     

A note on global output regulation of nonlinear systems in the output feedback form

This note shows how the adaptive control method developed recently for nonlinearly parameterized systems can be used to solve the problem of global output regulation, for nonlinear systems in the so-called output-feedback form with unknown parameters and exogenous signals belonging to a compact set whose bound is also unknown.     

五年来我国有色金属工业结构调整状况及对策建议

本文总结了近5年来我国有色金属工业结构调整和产业升级的基本情况,即中国有色金属工业集约化程度、技装备水平提高,生产成本下降,行业整体实力增强。而这些成绩的取得都有赖于国家积极的财政政策及“债转股”政策的推动,有赖于深化企业改革及发挥市场资源配置的作用等等。同时,针对对当前及今后有色金属工业结构调整和产业结构升级所面临的问题,提出了有关对策建议     

Composite group vector space method for estimating melting and boiling point of pure organic compound

Composition Group Vector Space (CGVS) method for estimating melting and boiling point T _m , T _b of organic compound has been proposed, and the principle of this method has been elucidated. The models for estimating T _m , T _b have been established and the numerical values of relative parameters have been presented. The average percentage deviations of T _m , T _b estimation are 7.53 and 1.58, respectively, which show that the present method demonstrates significant improvement in applicability to predict the above properties, compared to conventional group methods.     

添加VC的TiB2基硬质材料研究

对添加VC的TiB2基硬质材料进行了研究。通过实验测定了硬度、横向断裂强度、高温强度以及耐磨性等性能，通过观察SEM照片研究了VC对TiB2基硬质材料组织结构的影响。综合各种指标，我们确定在TiB2-Fe—Mo硬质材料中VC的最佳添加量为0．5％。