Corrosion characteristics of aluminium alloy graphite particulate composite in various environments

The present study was aimed at understanding the response of 2014 Al alloy dispersed with graphite particles in various corrosive environments. Marine (sodium chloride) as well as acidic media were selected for the purpose with a view to widen the range of utility of the composite for applications where such environments may be encountered. Studies were also extended to characterize the corrosion resistance of the composite in fresh as well as used lubricating oils to explore the possibilities of using it in bearing, bushing and such other applications. The corrosion behaviour of the base alloy processed under identical conditions was also examined in the above media to see the influence of graphite addition in the alloy. In order to assess the role of the matrix microstructure, the composite as well as the base alloy was subjected to corrosion in heat-treated as well as-cast conditions. It was observed that the specimens suffered from the maximum rate of corrosion in acid, while sodium chloride produced the minimum corrosion rate. Oil in both used and fresh conditions revealed a negligibly small extent of corrosion. The composite was found to show a higher rate of corrosion than the base alloy under identical test conditions. This was attributed to the dispersoid/matrix interfacial corrosion in the case of the graphitic aluminium alloy. Heat treatment of the composite and the base alloy was found to lower the rate of corrosion in the environments tested. Microstructural modifications of the matrix and possible relief of residual stresses were thought to be responsible for the lower rate of corrosion in the heat-treated condition.     

采用注视控制器实现复杂运动的仿真

注视控制器是3DS MAX软件的众多控件之一，它能使多个物体彼此间产生运动约束。通过使用注视控制器功能，笔者成功制作出八足爬壁式仿生机械昆虫的运动场景动画，并使该仿生机械昆虫各足的行走动作符合机械零件作平面复杂运动时所应遵守的正确运动规律。由此证明，3DS MAX软件注视控制器对正确模拟特殊机械装置的复杂运动可产生极大作用。     

用RAFA方法定量解析芳烃混合物的EEM

本文介绍了降秩因子分析(RAFA)方法,它是从一个多组分混合物中直接定量计算其中某一组分,而不必知道其它组分的物种及含量的一种定量分析的数学方法。它适用于双线性的数据。本实验首先将荧光分光光度计与外接计算机相连,以获得样品的激发-发射矩阵(EEM),再用RAFA方法对蒽、萘、菲、芘、芴、(艹屈)六种标样的一至五组分的混合物进行定量分析,获得满意的结果。     

Preparation of Ultra—fine Aluminum Nitride in Thermal Plasma

Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor.The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror(SEM),and the purity is at least over90% evaluated by X-Ray diffraction(XRD).The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3.Typical experimental parameters such as the feed rate of raw material,the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given.     

斜巷运输跑车事故原因分析和预防

通过对煤矿井下斜巷运输跑车事故原因的分析，提出预防措施。     

基于多智能体的数控机床资源共享技术研究

以数控铣床为对象，应用多智能体技术，以解决传统的资源共享所面lI缶的透明度低和效率低下的问题。首先，在分析功能模型的基础上，提出并实现了资源共享的四层网络拓扑结构；其次，构造了面向设备资源共享功能的智能体信息流模型，以实现四层结构之间的交互；其三，定义了智能体状态函数，并以此为依据，建立了智能体协商机制。所开发的原型系统表明，以上成果有效地提高了数控机床资源共享的透明度和效率。     

A fast algorithm for the generalized parametric minimum cut problem and applications

Many combinatorial optimization problems are solved by a sequence of network flow computations on a network whose edge capacities are given as a function of a parameter λ. Recently Galloet al. [7] made a major advance in solving such parametric flow problems. They showed that for an important class of networks, calledmonotone parametric flow networks, a sequence ofO(n) flow computations could be solved in the same worst-case time bound as a single flow. However, these results require one of two special assumptions: either that the λ values are presented in increasing or decreasing order; or that the edge capacity functions are affine functions of λ. In this paper we show how to remove both of these assumptions while obtaining the same running times as in [7]. This observation generalizes and unifies the two major results of [7], and allows its ideas to be applied to many new combinatorial problems. Of greatest importance, it allows the efficient application of binary search and successive binary search to a sequence of network flow problems.     

城市污水处理厂的施工监理

指出施工监理是一项细致而又责任重大的工作。把握好污水处理厂关键工序的施工及检查,才能对污水处理工程进行有效地控制和管理,使之发挥最大的经济和社会效益。     

砂岩储集层微波加热产生微裂缝的机理及意义

微波加热无需介质传热,具有升温速度快、热惯性小、选择性加热、穿透力强、过程易于控制等优点,已被试验性地应用于石油开采中。但有关微波加热对储集层岩石微观结构影响的研究还很缺乏,限制了该项技术在油气开采领域的广泛应用。通过实验手段研究了微波加热前后砂岩岩样微观结构变化、微裂缝产生机理及特征。结果表明,砂岩在微波加热过程中容易产生微裂缝,且不同岩石的微波加热致裂机理不尽相同,主要包括:矿物失水收缩、颗粒粒间开裂和颗粒内部开裂,低渗透致密砂岩刚性颗粒的粒内开裂作用显著。微波加热产生的微裂缝具非定向特征,即使在应力的作用下有一部分裂缝会发生闭合,但仍有大量微裂缝可以起到增加渗透率的作用。井下微波加热的致裂作用有助于改善近井区域渗流能力,提高低渗透油气藏的开采效率。图4参15     

溶剂萃取分离锂同位素研究Ⅱ.苏丹Ⅰ-中性配位体协萃体系萃取分离锂同位素效应探讨

文章讨论了苏丹I-中性配位体协萃体系萃取分离锂同位素中螯合剂和协萃剂的结构效应。为了获得高的同位素分离效应,螯合剂必须是弱酸性的(PK_α>11),具有强的分子内氢键及易于形成六元螯合环。协萃剂结构不仅要求无空间位阻,而且具有强的配位基。α随配位基的碱性增大而相应提高。萃取络合物中螯合环的增多亦有利于体系α的提高。此外本文还讨论了一些萃取体系的同位素富集方向和萃锂体系用于分离同位素的前景。