Exact axisymmetric solution of laminated transversely isotropic piezoelectric circular plates (Ⅱ)——Exact solution for elastic circular plates and numerical results

Emphasis is placed on purely elastic circular plates. Let the piezoelectric coefficients be equal to zero. Then two sets of uncoupled mechanical and electric equations are obtained and they can be solved independently. Two three-dimensional exact solutions of laminated transversely isotropic circular plate are derived under two boundary conditions, i.e. rigid slipping support and elastic simple support. For isotropic circular plates, the problem of multiple root is treated. At last, some numerical results of piezoelectric and purely elastic circular plates are presented and the applicability of classical plate theory is discussed.     

Liveness characterization for GFC systems(Ⅰ)

The significant features concerning liveness of generalized free-choice (GFC) systems are discussed.These features provide a sound basis for analyzing liveness of GFC systems in a reductive approach.What is interesting is that the characterization is just based on deadlocks,rather than on both deadlocks and traps as Commoner characterizes the liveness of ordinary free-choice systems.Several proof techniques for proving liveness-related features of GFC systems are introduced.     

Arc sensing system for automatic weld seam tracking(Ⅰ)——Mathematic model

Arc sensor, one of the most popular and effective sensors for automatic seam tracking of arc welding, is systematically studied. A mathematic model of the static and the dynamic properties of the sensor derived on the basis of control theory and experimental method are described. The model extends our understanding of arc sensor from qualitative level to quantitative level. This is important for its design and further development.     

催化重整工艺技术及其进展(Ⅰ)——工艺技术

催化重整是生产高辛烷值汽油组分和芳烃的重要工艺 ,并且能为炼厂提供廉价的氢气。随着我国汽油需求量的大幅度增加和环保法规的日益严格 ,要求各炼厂提供越来越多的辛烷值高、烯烃和硫含量低的重整汽油组分。催化剂分段装填技术和低压低苛刻度重整工艺都提高了重整产物的C5+ 产率。第三代连续重整技术提高了烧焦的灵活性并改善了铂重整催化剂的再生。我国开发的低压组合床重整工艺具有压力和氢油比低、液体产品收率和氢产率以及芳烃产率较高的特点 ;“逆流”移动床重整工艺克服了传统连续重整反应器中催化剂的活性状态与反应的难易程度不匹配的不足。综述了催化重整工艺技术的类型及主要进展 ,还讨论了我国催化重整工艺技术的发展趋势     

同步发电机励磁智能控制器(Ⅰ)——基本理论

本文对同步发电机励磁稳定控制,提出了一种基于规则和自学习的算法,以期改善同步发电机在不同运行工况下的稳定性。计算机数字仿真和模拟试验结果表明,本文提出的智能控制算法优于传统的励磁控制方式。     

Application and characterization of grafted polytetrafluoroethylene fiber for enhanced adsorption of Cu(Ⅱ) in aqueous solutions

An enhanced adsorption and desorption procedure of Cu(II) onto green synthesized acrylic acid grafted polytetrafluoroethylene fiber(i.e. AA-PTFE) was conducted with various chemical methods. The results show that the optimal adsorption condition is in acetic acid, sodium acetate(HAc-Na Ac) buffer solution(p H=6.80) with the initial concentration of 0.2 mg/mL. The process is very fast initially and equilibrium time is 12 h with a high Cu(II) uptake of 112.26 mg/g at 298 K. Various thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic in nature. In the elution test, 2 mol/L HCl solution achieves satisfactory elution rate and shows no significant decrease after 5 adsorption-desorption cycle, which indicates that AA-PTFE can be regenerated and reused, and due to which a reasonable amount of nondegradable polymer material is avoided in industrial use. Finally, PTFE, AA-PTFE fiber, and Cu(II) loaded AA-PTFE fiber were characterized with various techniques, including IR spectroscopic technique, SEM and EDS.     

Synthesis of 1,4-benzenedicarbonyl thiourea resins and their adsorption properties for Ag(Ⅰ)

Several 1,4-benzenedicarbonyl thiourea resins (BTR) were synthesized through interfacial polymerization between 1,4-benzenedicarbonyl diisothiocyanate and polyamine. Their structures were confirmed by FT-IR. The adsorption properties (including the effect of adsorption time,pH,initial concentrations and temperature) of BTR-1,BTR-2 and BTR-3 for Ag(I) were investigated by batch tests. The results show that the adsorption equilibria of BTR-1,BTR-2,BTR-3 for Ag(I) are achieved after about 10 h. Their equilibri...     

Real-time accurate hand path tracking and joint trajectory planning for industrial robots(Ⅰ)

Previously, researchers raised the accuracy for a robot′s hand to track a specified path in Car-tesian space mainly through increasing the number of knots on the path and the number of the path′s segments, which results in the heavier online computational burden for the robot controller. Aiming at overcoming this drawback, the authors propose a new kind of real-time accurate hand path tracking and joint trajectory planning method. Through selecting some extra knots on the specified hand path by a certain rule and introducing a sinusoidal function to the joint displacement equation of each segment, this method can greatly raise the path tracking accuracy of robot′s hand and does not change the number of the path′s segments. It also does not increase markedly the computational burden of robot controller. The result of simulation indicates that this method is very effective, and has important value in increasing the application of industrial robots.     

离心流化床干燥器性能的研究—— (Ⅰ)流体力学

研究了干燥转鼓转速、物料粒径、床载量、颗粒密度和形状系数对离心流化床压降和临界流化速度的影响。提出计算流化压降的修正式和临界流化速度的准数关联式,为进一步研究此设备的干燥性能打下基础。     

框架结构安定性分析(Ⅰ)——基本定理及简化

研究了结构安定分析的上、下限定理及变化荷载区域问题 ,提出了考察结构安定与否无需研究荷载全域 ,只要对载荷域的凸包 C0 (Ω )的边界点或顶点进行分析即可得出结论。     

水中微量杀虫脒的测定——(Ⅰ) 甲基橙比色法

植物和土壤中杀虫脒的总残留量的测定方法已有报道,它是基于杀虫脒经水解后逐步降解到4-氯-邻甲苯胺这一性质来定量测定的。用此法已测定了大米,水果,土壤等样品中杀虫脒的总残留量。 长链脂肪族伯,仲,叔胺在PH3—4时能与甲基橙形成黄色复合物,此复合物可被氯仿、二氯乙烷、四氯乙烷等有机溶剂所萃取,最大吸收在420毫微米处。杀虫脒为一脂     

文献资料的搜集和整理——课题的研究(Ⅰ)

0 前言任何研究工作都必须队搜集文献资料开始。如果说课题的研究是学术论文的基础,那末,文献资料则是研究工作的基础。这里说的文献资料,是指从查阅文献中获得的一系列事实(包括数据)以及解释这些事实的科学理论。在课题的研究中,文献资料是十分重要的。研究者可以从中掌握前人已经取得的科研成果,了解本学科的研究历史、现状和发展趋势,从而确定自己的研究方向,选择具体的研究课题,避免重复劳动;研究者可以从中了解到他人从事有关研究工作的经验教训,作为自己的     

跨断层地下管线振动台模型试验研究(Ⅰ)——试验方案设计

为了解决黏土中逆断层错动下埋地钢管的力学性能问题,采用有限元软件建立三维非线性管土相互作用数值分析模型,分析逆断层错动对穿越断层的埋地钢管的影响机理,给出不同断层倾角下、不同管道内压下和不同管道径厚比下3种典型失效模式,即：管道的受拉失效、局部屈曲和横截面过度变形,所对应的临界逆断层错动量. 结果表明：当逆断层倾角为75°时,管道发生局部屈曲破坏所需的断层位错量最小,为管道跨逆断层最不利倾角;较大的管道内压,可有效抑制管道横截面过度变形,且随管道内压逐渐增大,管道的控制失效模式由管壁局部屈曲变为受拉失效;增加管道径厚比可显著提高管道的抗变形能力.

     

纯涤纶织物阻燃整理探讨(Ⅰ)——高温高压整理法

本文探讨了含Ｐ、Ｃｌ的阻燃剂ＴＣＥＰ对于纯绦纶织物的阻燃整理工艺，采用高温高压整理法阻燃整理织物，用垂直燃烧法、氧指数法、织物含Ｐ量、皂洗牢度测试阻燃效果，提出了最佳整理工艺，同时探讨了乳液稳定性问题。热分析结果进一步证实了所选工艺的正确性。     

稀土络合催化环氧丙烷聚合——(Ⅰ)聚环氧丙烷的合成

本文研究了稀土催化体系合成环氧丙烷的特征。发现许多稀土元素的膦酸酯盐和环烷酸盐与三异丁基铝及水组成的三元催化体系是聚合环氧丙烷的优良催化剂。着重研究了钕的2—乙基已基膦酸酯盐[Nd(P_(204)3]体系的聚合情况。所得聚合物的粘均分子量可达二百五十万;产物的立体规整性亦较高。研究了水及其它添加组分对催化活性、产物的分子量及等规性的影响。     

把握科技英语的逻辑结构(Ⅰ)——阅读中的逻辑思维

本文讨论的是一个高级阅读技巧的问题。文章从八个方面对科技英语的逻辑结构作了探讨性的表述:1.概念关系,2.定义,3.划分,4.判断关系,5.比较,6.推论,7.概括,8.篇章结构。     

沥青纤维的预氧化研究(Ⅰ)——纤维结构的变化

为了对国产各向同性石油沥青纤维的氧化性能进行分析,给今后深入系统地研究其氧化规律打下基础,本文用自制的氧化炉将软化点在220～243℃范围内的四种沥青纤维于空气中进行了预氧化处理,对原丝及预氧化丝进行了增重分析、元素分析、红外分析和在氯仿中的不溶性分析。结果表明:在选定的氧化条件下,沥青纤维的分子之间产生了交联结构,预氧化丝的耐热性和不溶解性都得到了明显的改善。这说明国产通用级石油沥青具有制造碳纤维所需的氧化性能。     

氯乙烯工艺流程模拟软件的开发——(Ⅰ)数学模型与软件结构

通过对氯乙烯工艺过程进行分析研究,考察了各种热力学模型对氯乙烯过程的适用情况,建立了模拟氯乙烯工艺过程的数学模型,通过对大量数据进行模拟分析,建立了一个适用于氯乙烯工艺过程计算的相互作用参数数据库,以及氯乙烯工艺流程的图形库和程序库。     

涤纶废丝的综合利用(Ⅰ)——制取对苯二甲酸和清洗剂

本文介绍了由涤纶废丝碱解制取合格的对苯二甲酸,同时回收副产物清洗剂。成本低,无二次污染,具有明显的环境效益和可观的经济效益。