广义人工生命的科学基础(I):工程技术基础

根据广义人工生命研究的特点,作者把系统论、控制论、信息论、人工智能、元胞自动机、L-系统、遗传算法、进化策略、进化规划、耗散结构理论、协同学、突变论、混沌、分形、转基因技术、克隆技术等的研究成果视为人工生命研究的主要科学基础。文章力求对元胞自动机、L-系统、遗传算法、进化策略、进化规划、耗散结构理论、协同学、突变论、混沌、分形和它们与人工生命的关系做系统而扼要的评述,为人工生命研究提供方便。     

增强现实技术的应用和研究

增强现实技术是近年来逐渐发展起来的新兴研究领域。文章概要地介绍了实现增强现实系统的关键技术和设备,以及需要解决的难点———准确定标问题,和目前提出的相应解决方案。该文为所有对研究和使用增强现实技术产生兴趣的人提供了一个崭新的起点。     

圆柱体质心测量中转角取值分析

为获得质量非均匀圆柱体质心的三维坐标，测量时需使圆柱体转过一定的角度。分析表明，转角最好取为90度以获得最佳测量效果。如果受条件限制，宜在45度到90度之间选取，尽量避免取小于30度的值。     

参数自适应模糊PID控制器在温度控制系统中的应用

电阻炉模型参数具有随温度而变化的时变特性．当温度大范围变化时．采用常规PID控制方法不能满足较高工艺要求．为此，本文应用一种参数自适应模糊PID控制方法，并设计了基于单片机的温度控制硬件装置。实践证明该控制方法有较高的稳态精度和跟踪性。装置简单，运行效果较好。     

NdFeB铸块在HD工艺中的吸氢行为研究

采用真空感应炉熔炼合金 ,用不锈钢压力罐充入H2 进行HD实验 ,对NdFeB铸块在HD工艺中的吸氢行为进行了研究。研究发现 ,Nd FeB铸块在氢爆过程中明显存在孕育期 ,其吸氢过程分为 3个阶段 :慢速吸氢阶段、快速吸氢阶段和缓慢吸氢阶段 ;随氢气压力 (1～ 4× 10 5Pa)的升高 ,孕育时间缩短 ,吸氢更快 ,当压力达到了 2～ 3× 10 5Pa时 ,获得较好的HD效果 ;随铸块粒度的减小 ,孕育时间缩短 ,吸氢越彻底。研究同时发现 ,随温度的升高 ,NdFeB铸块吸氢越迅速 ,当温度升至一定程度时 ,孕育期消失 ,3 5 3K时吸氢效果最佳。     

Design of a permanent magnetic circuit with air gap in a magnetic refrigerator

We calculate the magnetic field distribution of a permanent magnetic circuit with an air gap in a magnetic refrigerator by a finite-element method, and compare the field strengths of different structural parameters of the magnetic circuit. We show how the structure of the magnetic circuit can be optimized and present some approaches to improve the structure for a specific magnetic circuit. The main purpose is to provide basic parameters for the design of a practical magnetic refrigerator.     

Investigation of Optimal Megnetic Properties in NdFeB Magnets by Artificial Neural Network

In order to study the effect of alloy component on magnetic properties of NdFeB magnets, the experiment schemes are carried out by the uniform design theory, and the relationship between the component and the magnetic properties is established by artificial neural network(ANN) predicting model.The element contents of alloys are optimized by the ANN model.Meanwhile, the influences of mono-factor or multi-factor interaction on alloy magnetic properties are respectively discussed according to the curves ploted by ANN model.Simulation result shows that the predicted and measured results are in good agreement.The relative error is every low, the error is not more than 1.68% for remanence Br, 1.56% for maximal energy product (BH)m, and 7.73% for coercivity Hcj.Hcj can be obviously improved and Br can be reduced by increasing Nd or Zr content.Co and B have advantageous effects on increasing Br and disadvantageous effects on increasing Hcj.Influence of alloying elements on Hcj and Br are inverse, and the interaction among the alloying elements play an important role in the magnetic properties of NdFeB magnets.The ANN prediction model presents a new approach to investigate the nonlinear relationship between the component and the magnetic properties of NdFeB alloys.     

Investigation of the firing voltage in a shadow‐mask PDP

Abstract— A numerical method was used to investigate the firing characteristics of the discharge cell in an AC shadow‐mask PDP (SM‐PDP). The firing voltages for the various discharge paths in the addressing and sustaining periods were calculated, and the effects of the metal barrier rib and the dielectric layer in the discharge cell on the firing characteristics were studied. Furthermore, the advantages of the SM‐PDP in terms of the firing characteristics will be discussed.     

基于H∞控制器的柔性机械手优化设计研究

针对柔性机械手设计中手臂变形涉及的柔性和参数分布式系统的复杂性,采用H∞控制技术对柔性机械手进行优化设计。在设计过程中,考虑了参数分布式系统中各子系统之间的相互作用,分析了模型的不确定性并进行了定量描述,导出了广义装置的空间状态方程。设计了具有稳定闭环的H∞控制器,减小了系统的不确定性和扰动所产生的各种影响,从而解决了控制问题和模型精度问题。对阶跃输入和扰动的响应进行了研究,给出了各种情形的数值结果,显示系统具有良好的鲁棒性。     

锂对工业纯铜力学性能的影响

在工业纯铜中加入微量锂,可提高工业纯铜硬态丝的抗拉强度和延伸率,这是由于锂的加入引起铜的晶格畸变从而产生固溶强化所致。同时,锂的加入提高了工业纯铜的再结晶强度,在铜的常规热处理制度下,试样仍保持较多的形变组织,从而退火后其强度下降较少,延伸率提高也较小。