水力脉冲式钻井工具的研制与应用

水力脉冲式钻井是利用特定的工具使钻井管柱中的连续流转变为脉冲射流,从而改变井底流场的压力状况,进而提高机械钻速的一种钻井新工艺。在分析水力脉冲产生机理的基础上,探讨了基于瞬变流理论的机械阻断式水力脉冲破岩机理,介绍了SLPMC机械阻断式水力脉冲工具的工作原理及结构特点,简单叙述了该工具在胜利油田进行的2口井的现场试验情况。该钻井工具对于提高机械钻速和降低钻井成本具有一定的积极意义。     

可编程控制器在捆扎机自动控制中的应用

介绍了一种用可编程控制器（PLC）实现捆扎机自动控制的设计方案，详细地介绍了设计过程，给出了完整的程序流程图和部分控制程序。     

基于切削振动相关性识别刀具磨损状态的模型与实验

本文提出基于切削振动相关性识别刀具磨损状态的研究思想,建立了车削中刀杆双向横振动系统及其单输入双输出系统的数学模型。理论和实验均表明,刀杆双向横振动之加速度响应在固有基频处的相干函数与刀具磨损状态之间有很好的规律性,它反映了两者之间的本质机理,并提供了识别刀具磨损状态的新途径。     

用分解法编制轴类零件图程序

采用分解法编写轴类零件程序，即将具有典型结构的轴分解成若干部分，把每一部分编成通用子程序，连同尺寸标注子程序、表面粗糙度子程序、剖面线子程序、尺寸公差及形位公差子程序等一并存贮在程序库中，需要时一一调用。     

The Lazy Cook Problem, or Scheduling Two Parallel Machines to Optimize Vehicle Utilization

A cook has to prepare n cakes using an oven with two racks. According to the recipe, the i-th cake has to be baked for exactly a _i minutes. Cakes to be cooked are taken from a table and carried to the oven, and once cooked are carried back to the table by means of a trolley that can carry two cakes at a time. What is the minimum number q ^* of round trips required of the cook? This problem has application to the operation scheduling of transportation systems and to material cutting. A different problem arises according to whether the cook accepts or not to stay near the oven for awhile with the trolley. If the trolley cannot be idle at the oven, an optimum schedule with no oven idle-time always exists: consequently, the trolley schedule is trivial, and the problem is transformed into a set packing. For this case, we propose and test a heuristic method which generates all of the promising columns of the set packing, and solves the resulting problem by branch-and-bound. Instead, if the trolley can be idle at the oven for a limited amount of time, a problem arises to find an optimal schedule of the trolley: in this case we show how to use a scaling technique in order to obtain a very good feasible solution by the method above.     

Machine translation of non-literary texts: Some Canadian experiences

A survey was carried out of past and current Canadian experiences with machine-aided translation (MAT) systems of non-literary texts in one government institution and three industrial settings. Each organization requires a great deal of translation and had conducted several experiments in the use of MAT. The survey supports positive conclusions about the prospects for expanded use of computers in translation.The authors express their thanks to all those who helped in the preparation of this paper. We are particularly grateful to the staff of the translation departments of the organizations mentioned in the paper for their kind cooperation and their willingness to answer our questions: Chantal Delorme ofIBM Canada, Lorraine Desmarais and Mr. Plamondon of Bell Canada, Pierre Tellier of the Department of the Secretary of State, Maria Russo and Raymond Lapointe of the Xerox Corporation. Furthermore we thank Prof. Graeme Hirst for helpful discussion.     

分布系统中多米诺效应的分析与消除

分布系统中发生故障后,错误信息在进程间的传播,以及由此引起的系统恢复过程中的多米诺效应是分布系统容错恢复技术所面临的最重要与最困难的问题.目前各种研究工作偏重于具体的系统动态恢复技术.本文的研究重点在于首次揭示多米诺效应本身固有的数量特征及其与分布系统技术参数间的联系,给出多米诺效应动态消除技术,引入系统额外开销的下限,并针对动态技术的缺点,探讨多米诺效应的静态消除技术,为解决困难开辟新途径.     

SC文法功能体系

文法体系的研究一直是自然语言处理研究的核心问题之一.但是,由于自然语言本身所固有的复杂性和非规范性,多义问题始终未能得到圆满的解决.本文提出了SC文法(A SubCategory grammar for integrating Se-mantic and Case analysis),它是一种基于传统的上下文无关文法、语义文法,以及超前与反馈分析技术和格框架约束分析等技术的上下文相关处理文法.该文法不仅能继承传统的上下文无关文法的表示简洁、处理方便的特点,而且能实现语法和语义一体化分析和处理上下文相关以及复杂多义问题.     

Effect of carbide additions on grain growth in TiC−Ni cermets

The growth of carbide particles in TiC-XC-2 vol.% Ni and TiC-XC-30 vol.% Ni alloys, where X=Zr, Cr, W, Ta and Mo, was fitted to an equation of the form d³-d_o ³=Kt. The grain growth behavior during liquid phase sintering at 1673K decreased markedly with the addition of Mo₂C or WC, changed little for TaC, and increased with the addition of ZrC or Cr₃C₂. The grain contiguity decreased with increasing Ni content in the TiC−Mo₂C−Ni alloy and was greater in the alloys with smaller growth rate constant. Consequently, the effect of carbide addition on the grain growth of 2 vol.% Ni alloys was found to be similar to that of 30 vol.% Ni alloys. The grain growth mechanism could be explained by the effect of contiguous carbide grain boundaries in restricting the overall grain growth, as well as the area of the solid/liquid interfaces in the alloy by the usual solution/reprecipitation model.