An Object-Oriented Transaction Model

In object-oriented database systems(OOBSs),the traditional transaction models are no longer suitable because of the difference between the object-oriented data model(OODM)and the conventional data models(e.g.relational data model).In this paper,transction models for advanced database applications are reviewed and their shortcomings are analyzed.Exchangeability of operations is proposed instead of commuativity and recoverability for using more semantics in transaction management.As a result,an object-oriented transaction model(in short,OOTM)is presented.It is not modeled for some special application,but directly based on object-oriented paradigms.A transaction is regarded as an interpretation of a metho.Each transaction(even subtransactions)keeps relative ACID(Atomicity,Consistency,Isolation,Durability)properties,therefore the special problems appearing in OOBSs such as“long transactions”,“visibility of inconsistent database state”can be solved.     

Interface microstructure and reaction in Gr/Al metal matrix composites

The interface structure in Gr/Al composites fabricated with liquid metal infiltration has been studied using transmission electron microscopy (TEM). Morphologies of interfacial reaction product, aluminium carbide Al₄C₃, formed at different manufacturing parameters were compared and, the growth mechanism of the carbide was studied by means of high resolution electron microscopy (HREM). It has been shown that the morphology of the carbide is intimately related to the processing parameters with which the composites were produced. There are two kinds of interfaces between the carbide and the aluminium matrix. They have different growth mechanisms and relative growth rates under different growth driving forces. Several crystal orientation relationships between the carbide and the aluminium matrix have been observed.     

相转移法制备高纯超细TiO2技术研究

报道了用相转移法制备高纯超细ＴｉＯ２的新技术；探讨了Ｔｉ（Ⅳ）从有机相转移到水相发生水解反应的机理 ；通过ＴＧ－ＤＴＡ分析以及ＸＲＤ物相分析对水解产物的组成、热分解机理，晶型转变规律进行了研究，建立了水解产物焙烧的最佳温度。     

巨型机转子机制的改进策略

本文分析了通用寄存器型计算机和通用堆栈型计算机处理转子指令的不同方法,研究了类Cray-1转子机制的实现原理,提出了在类Cray-1通用寄存器型模型机上采用堆栈来处理转子指令的实现方法。     

Electrochemical Investigation on the Formation of Dy-Fe Alloy in Molten Chlorides

ＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＩｎｖｅｓｔｉｇａｔｉｏｎｏｎｔｈｅＦｏｒｍａｔｉｏｎｏｆＤｙＦｅＡｌｏｙｉｎＭｏｌｔｅｎＣｈｌｏｒｉｄｅｓＬｉｕＧｕａｎｋｕｎ（刘冠昆），ＴｏｎｇＹｅｘｉａｎｇ（童叶翔），ＨｏｎｇＨｕｉｃｈａｎ（洪惠婵），Ｙａｎｇ...     

液体火箭发动机研制情况的一些回顾

４０年来，我国液体火箭发动机的研制工作取得了很大成绩。文中对发动机的一些研制情况作了回顾，对ＹＦ－７３和ＹＦ－７５氢氧发动机的设计特点、飞行结果作了简单叙述。对今后工作也提出了看法。     

MPC系统模块结构中的流场研究

本研究中,应用Simple数值计算方法开发了求解MPC系统模块结构中二维流场分布的计算软件。为了验证计算结果的精确性,用多普勒测速仪实测了用有机玻璃制成的MPC模块二维模型的流场,模拟计算结果与实测值对比取得了较好的一致性。四种不同流出角的MPC模块平均总压损失计算结果表明,已开发的软件可作为设计低流阻MPC模块的良好工具。     

Visual C++与Fortran混合编程及Matcom绘图在空调负荷计算软件中的应用

介绍利用VC与Fortran进行混合编程，将Visual C 程疗从DOS环境下移植到期Windows环境下，并利用Matcom对数据进行可视化的方法。     

软土地基地下结构的一个CAD软件

本文介绍地下结构计算机辅助设计软件——UCAD的总体结构、主要功能以及解决的问题。