机械设备故障诊断与监测技术的发展趋势

机械设备故障诊断及监测技术在现代工业中发挥着十分重要的作用。体文主要介绍了故障诊断与监测技术的常用方法，以及在信号分析、诊断仪器、诊断系统和网络化等方面的发展。     

石墨烯在防腐防污涂料中的应用

随着石墨烯技术的问世,很多行业展开了对石墨烯的研究.石墨烯是一种新型材料,化学性质非常稳定,具有较强的抗氧化性,不易因外界因素的影响而发生变化,并且,石墨烯在处于氧气、水等腐蚀介质中时具有较强的抗渗透性.研究人员将其加入到防腐涂层中进行研究,并起到了良好效果,本文将以此为主题进行介绍.     

<Emphasis Type="Bold">Optimisation of Plastic Injection Moulding Process with Soft Computing</Emphasis>

The paper presents a hybrid strategy in a soft computing paradigm for the optimisation of the plastic injection moulding process. Various plastic injection molding process parameters, such as mold temperature, melt temperature, injection time and injection pressure are considered. The hybrid strategy combines numerical simulation software, a genetic algorithm and a multilayer neural network to optimise the process parameters. An approximate analysis model is developed using a Back-propagation neural network in order to avoid the expensive computation resulting from the numerical simulation software. According to the characteristic of the optimisation problem, a nonbinary genetic algorithm is applied to solve the optimisation model. The effectiveness of the improved strategy is shown by an example.     

纳米级研磨技术及发展动向

概述了最近纳米级研磨技术的研究动态,同时介绍了研磨技术的原理、应用和优势,结合该方向的最新研究成果提出其近期的研究发展方向.     

基于PID算法的无线温湿度控制系统

本系统采用两片单片机AT89C52作为控制核心,实现多路温湿度检测、无线温湿度数据传输和控制、LCD显示、语音报警等功能.采用PID算法产生的PWM波来实现对温湿度的调节,可以有效地协调动态与稳态的关系,使系统达到最优化.     

EFFECT OF CARBON CONTENT ON MICROSTRUCTURE AND PROPERTIES OF HIGH STRENGTH AND HIGH ELONGATION STEELS

The micro structure and mechanical properties of new kind of hot-rolled high strength and high elongation steels with retained austenite were studied by discussing the influence of different carbon content. The research results indicate that carbon content has a significant effect on retaining austenite and consequently resulting in high elongation. Besides, new findings about relationship between carbon content and retained austenite as well as properties were discussed in the paper.     

稀土变质剂对超低碳钢铸态晶粒细化的研究

研究了稀土变质剂对超低碳铸钢晶粒尺寸的影响。结果表明，变质处理后超低碳铸钢中形成大量的高溶点化合物，电子探针分析表明其组成主要为稀土氧化物Ce2O3。这些高熔点化合物作为非均匀形核核心，增加了液固相变形核位置，使铸态晶粒尺寸明显减小，材料屈服强度显著提高。     

金刚石锯片失效分析和强化方法

本文分析了金刚石锯片刀头失效的主要原因。采用扫描电子显微镜、能谱仪、硬度仪、光学显微镜等手段对金刚石锯片的刀头材料、微观组织及其与锯片耐磨性进行研究。研究结果表明，通过添加微量稀土合金元素后，细化了胎体合金晶粒组织，改善了胎体与金刚石的结合状况，可使胎体金属对金刚石的包镶致密、把持力明显增大；添加富铈稀土和铬合金元素的锯片胎体耐磨性都有提高，其中添加富铈稀土效果尤为明显。多种添加物的添加，其对耐磨性的增加作用也有叠加，其中添加稀土与铬合金元素的锯片磨损系数降低，提高了胎体合金的耐磨性，使其耐磨率降低了20％。     

A parallel two-list algorithm for the knapsack problem

An n-element knapsack problem has 2ⁿ possible solutions to search over, so a task which can be accomplished in 2″ trials if an exhaustive search is used. Due to the exponential time in solving the knapsack problem, the problem is considered to be very hard. In the past decade, much effort has been done in order to find techniques which could lead to practical algorithms with reasonable running time. In 1994, Chang et al. proposed a brilliant parallel algorithm, which needs O(2^n/8) processors to solve the knapsack problem in O(2^n/2) time; that is, the cost of Chang et al.'s parallel algorithm is O(2^5n/8). In this paper, we propose a parallel algorithm to improve Chang et al.'s parallel algorithm by reducing the time complexity to be O(2^3n/8) under the same O(2^n/8) processors available. Thus, the proposed parallel algorithm has a cost of O(2^n/2). It is an improvement over previous literature. We believe that the proposed parallel algorithm is pragmatically feasible at the moment when multiprocessor systems become more and more popular.     

涡一速度形式Navier-Stokes方程不可压粘流内流流场的数值计算

本文给出了适应于叶轮机械内流场计算的涡-速度形式的N.S方程,分别用传统和作者提出的展开方法,将涡-速度形式的N.S方程在非正交曲线坐标系下展开,并对两种方法进行了比较。对涡-速度形式的N.S方程的特点进行了详细讨论。最后用涡-速度方程组和本文提出的展开方法分别计算了几种内流流场。