SIEMENS过程控制系统PCS7在多功能连续乳液聚合中试装置设计中的应用

一、工程概述本装置的主要原料有除氧剂、扩散剂、皂液、电解质、丁二烯、苯乙烯（丙烯腈）等,由单体贮存、化学品配制、聚合、单体回收、胶浆贮存及掺混、凝聚干燥包装、装置管廊等功能单元组成,最终生产一系列的胶乳产品。为了顺利完成工艺过程,本装置涉及了串级调节、变频调速、液位报警等控制手段来实现过程控制。     

在线工业色谱仪在测定MTBE装置醇烯比中的应用

阐述在MTBE装置中通过在线工业色谱技术来分析醇烯比的原理及其优缺点,并根据其在实际生产过程中的应用,提出了这种方法仍需进一步的改善和提高。     

边界元法中奇异积分计算的极坐标变换法

在边界元法中,奇异积分的处理是一个极为引人注目的问题.本文提出了一种在单元状态作极坐标变换的新的处理方法,它能显式地消除奇异积分的奇异性,使之成为常规积分,因而易于在边界元法中使用高次单元.计算实例表明,本文所提出的方法是有效的、方便的.     

自控工程设计中控制阀的选型

阐述了控制阀的选型在过程控制中的重要性及控制阀的工作原理,对控制阀结构形式和材料、流量特性、控制阀口径、辅助装置、作用方式、执行机构等六大选型原则进行了重点论述。     

POLAR COORDINATE TRANSFORMATION APPROACH FOR TREATMENT OF SINGULAR INTEGRALS IN BOUNDARY ELEMENT METHODS

In boundary element methods the treatment of singular integrals, as one of the main numerical problems has been noticed seriously. In this paper, by using polar coordinate transformation for elements a new approach is proposed to remove the singularities in the integrals explicitly. The formulations for treatment of the singularities in quadrilateral boundary elements with four nodes, eight nodes and nine nodes are derived and it can be extended easily to other higher order boundary elements. Numerical examples are given. The results show the present approach is effective and efficient.     

边界元法中对称面条件处理的场点映射法

本文充分利用了格林函数本身的对称性和互易性,建立了更完善、更有效的对称面条件处理的场点映射法.它用对称面把物体分成基本体和非基本体,通过作场点 p 关于对表面的映射,来正确反映非基本体的影响,计算仅需离散基本体的原有物体表面(不包含对称面).与其他方法相比,本方法不受无限域的影响,不会带来附加的奇异性和新的棱边角点;仅与场点有关而与单元特性无关,因此,完全适合在高阶边界元中使用.     

Polar coordinate transformation approach for treatment of singular integrals in boundary element methods

In boundary element methods the treatment of singular integrals, as one of the main numerical problems has been noticed seriously. In this paper, by using polar coordinate transformation for elements a new approach is proposed to remove the singularities in the integrals explicitly. The formulations for treatment of the singularities in quadrilateral boundary elements with four nodes, eight nodes and nine nodes are derived and it can be extended easily to other higher order boundary elements. Numerical examples are given. The results show the present approach is effective and efficient.