JITL-based concentration control for semi-batch pH-shift reactive crystallization of l-glutamic acid

Although concentration control (C-control) strategy has been shown to give effective and robust control performance for batch cooling and semi-batch antisolvent crystallizations in recent years, no research work was reported concerning the potential application of conventional C-control for the more challenging semi-batch pH-shift reactive crystallization that is common in the process industries. To this end, this paper presents detailed analysis to find out that it is not feasible to apply the C-control to semi-batch pH-shift reactive crystallization. To circumvent this problem, a variant of C-control strategy by incorporating the Just-in-Time Learning (JITL) method to cope with strong process nonlinearity inherent in the pH-shift reactive crystallization is developed in this paper. Simulation results are presented to illustrate the proposed design and a comparison with conventional optimal control is made.     

Processing study of a high temperature adhesive

An adhesive-bonding process cycle study was performed for a polyimidesulphone. The high molecular weight, linear aromatic system possesses properties which make it attractive as a processable, low-cost material for elevated temperature applications. The results of a study to better understand the parameters that affect the adhesive properties of the polymer for titanium alloy adherends are presented. These include the tape preparation, the use of a primer and press and simulated autoclave processing conditions. The polymer was characterized using Fourier transform infrared spectroscopy, glass transition temperature determination, flow measurements, and weight loss measurements. The lap shear strength of the adhesive was used to evaluate the effects of the bonding process variations.     

4-氨基吡啶的合成技术进展及其应用

评述了4-氨基吡啶的合成研究进展,重点介绍了硝基氮氧化吡啶法工艺。概括介绍了4-氨基吡啶在医药、农药、染料等领域的应用状况以及在国内外的生产现状。指出4-氨基吡啶合成工艺的难点在于降低生产成本,提高反应收率以及减少环境污染。建议从催化加氢还原或电化学还原过程中找到一条合乎国情的工艺路线,以推动我国吡啶系列产品的研发工作。     

On the thermal stability of xanthan gum

The thermal stability of xanthan gum in dilute aqueous solutions at 90°C is considered. The relative viscosity as a function of ageing time is discussed, and it has been found to depend on the polymer concentration and conformation as well as on the salt content. The effectiveness of a quencher demonstrates the existence of a free-radical process in the degradation. During ageing, the molecular weight first decreases by rapid random hydrolysis of the main chain and loss of the pyruvate and acetate substituents. Later, oligomers are formed corresponding to a breakdown of both the side chain and the main chain. The identification of cellodextrins in the oligomer pool demonstrates the second effect.     

电子陶瓷和器件的低温共烧技术

较系统地介绍了电子器件用低温共烧陶瓷(low temperature cofired ceramics,LTCCs)材料,探讨了其工艺中的若干问题。电子器件用低温共烧陶瓷材料包括:玻璃/陶瓷复合材料、结晶化玻璃、晶化玻璃/陶瓷复合材料以及液相烧结陶瓷,其中典型的和最为常用的LTCCs为玻璃/陶瓷(特别是氧化铝)复合材料。正在研究的一些陶瓷介质材料中,Bi基介质材料引起了人们的关注。玻璃/陶瓷复合材料的制备工艺中,应当着重关注和加深了解玻璃的流动性和结晶性、玻璃的起泡、玻璃和陶瓷颗粒间的反应、共烧材料的匹配等问题,从优选材料配方和优化工艺着手,从而获得优质可靠的材质和器件。     

乙烯二聚制高纯丁烯－1技术经济评价

本文对生产高纯度丁烯－１的Ａｌｐｈａｂｎｔｏｌ工艺进行了技术经济评价，认为该工艺条件简单、反应条件温和，而且投资少，所以很适合事在发展中国家应用。     

可监控EXE进程的Windows服务程序设计

EXE进程一旦意外停止,将给应用带来严重后果。该文基于微软的基础平台开发库设计了一个Windows服务程序,该服务程序在机器启动时自动运行指定EXE进程,在服务程序工作线程组中监控EXE进程运行状态,自动重启已停止进程,此服务程序可实现一个或多个EXE进程不间断运行。     

动态挖掘进程内在机制研究

针对动态挖掘进程内在运行机理,通过对动态挖掘进程中不同挖掘任务的优化分析以及动态挖掘进程和生物免疫过程之间的对比分析,提出了动态挖掘进程的eDMP机制;定义健壮型协调器,融合进化计算和免疫算法,设计了eDMP机制的实现方案;在理论分析和方案设计的基础上,给出了eDMP机制的一般流程。实验结果表明,eDMP机制及其实现方案在解决动态挖掘问题上有效、适用。     

Study of the physico–chemical characteristics and rheological behaviour of boehmite dispersions for dip-coating applications

Dispersions of a totally dispersible AlOOH powder have been studied. The effect of the initial composition has been studied to outline the reactions that determine the final rheological behaviour of the dispersions. The final viscosity and viscoelastic properties of the dispersions are determined by the sol–gel phenomena occurring during the ageing treatment. Gel formation is favoured by low water and high acid contents, while it is disfavoured by prolonged stirring. Gelling time from 48 h to 4 months has been observed depending on the initial composition.