液晶分子附着能和盒间隙对响应时间的影响

通过理论分析和实验研究液晶分子附着能和液晶盒间隙对响应时间(τ0)的影响。用液晶盒有效间隙法和表面动力学方程法两种方法推出分析公式,由这两种方法推出的结果是一致的。实验数据与简化方程τ0-dx基本拟合(其中d是液晶盒的间隙,x是指数)。在两种极端的(极大或极小)附着能极限下,指数x分别接近2和1。这个结论有助于优化液晶显示器件的应用。     

Interfacial polycondensation of diphenolic acid and isophthaloyl chloride

Interfacial polycondensation of diphenolic acid (DPA) and isophthaloyl chloride (IPC) in various solvent/water systems was investigated with tetrabutyl ammonium chloride as a phase transfer catalyst. It was found that a large mass of capsules were formed at the beginning of the reaction for all solvents examined but the capsule morphology and reaction results depended on the solvents. It is believed that the capsule shells make up of the reaction zone and a mechanism of the interfacial polycondensation is proposed accordingly. The effect of the solvents on the reaction was interpreted from the interaction between the polymer and the solvent according to the mechanism. The reaction conditions were optimized, and poly(DPA-IPC) with high intrinsic viscosity was prepared in high yield under the optimal condition. It is an amorphous polymer with glass transition temperature of about 160°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Viscoelastic properties of polyarylene ether nitriles/thermotropic liquid crystalline polymer blend

Polyarylene ether nitriles (PEN)/thermotropic liquid crystalline polymer (TLCP) blend was prepared via melt mixing. The immiscible phase morphologies, linear and nonlinear, as well as transient viscoelastic properties of the blend were studied using SEM, rheometer, and DMA. The linear dynamic viscoelastic behavior of the blend shows temperature dependence due to further evolution of the immiscible morphology and, as a result, the principle of time‐temperature superposition (TTS) is invalid. In the steady shear flow, the discrete TLCP phase is difficult to be broken up because of the high viscosity ratio of the blend systems, while is easy to be coarsened and followed by elongation, and finally, to form fibrous morphology at high TLCP content and high shear level. During this morphological evolution process, the transient stress response presents step increase and nonzero residual relaxation behavior, leading to increase of the dynamic viscoelastic responses after steady preshear. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polysaccharide‐based artificial extracellular matrix: Preparation and characterization of three‐dimensional,macroporous chitosan,and heparin composite scaffold

Scaffold‐guided tissue engineering based on synthetic and natural occurring polymers has gained many interests in recent year. In this study, the development of a chitosan‐heparin artificial extracellular matrix (AECM) is reported. Three‐dimensional, macroporous composite AECMs composed of heparin (Hep) and chitosan (Chito) were prepared by an interpolyelectrolyte complex/lyophilization method. The Chito‐Hep composite AECMs were, respectively, crosslinked with glutaraldehyde, as well as cocrosslinked with N,N‐(3‐dimethylaminopropyl)‐N′‐ethyl carbodiimide (EDC/NHS) and N‐hydroxysuccinimide (NHS). The crosslinking reactions were examined by FT‐IR analysis. In physiological buffer solution (PBS), the EDC/NHS‐crosslinked Chito‐Hep composite AECM showed a relative lower water retention ratio than its glutaraldehyde‐crosslinked counterparts. The EDC/NHS‐crosslinked Chito‐Hep composite AECMs showed excellent biocompatibility, according to the results of the in vitro cytotoxic test. This result suggested that the EDC/NHS‐crosslinked Chito‐Hep composite AECMs might be a potential biomaterial for scaffold‐guided tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects and properties of poly(arylene ether benzonitrile)s of various molecular weights blended with sulfonated poly(ether ether ketone)

Poly(arylene ether benzonitrile) (PAEBN) was synthesized with 2,6‐dichlorobenzonitrile and biphenol. PAEBNs with various molecular weights (MWs), 1,640,000 and 185,000 g/mol, were synthesized by control of the stoichiometry of the monomers and were blended with sulfonated poly(ether ether ketone) (SPEEK). The effects of MW on the water uptake, swelling, methanol permeability, and proton conductivity of the SPEEK/PAEBN blend membranes were investigated. The molecular mobility of the SPEEK/PAEBN blends was also examined in this study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

改烧贵州煤后栲胶脱硫系统存在的问题及解决

栲胶法脱硫具有硫容高、副反应少、传质速率快、脱硫效率高且稳定、原料消耗低、腐蚀轻、硫磺回收率高等优点, 自投入工业应用以来,已在中小氮肥厂、炼焦、城市煤气、环保等行业得到了广泛应用.从实际应用情况看,绝大多数厂脱硫效果良好,但有关栲胶脱硫对不同煤种的适应性这一问题目前还少有文章进行探讨.本文对我公司从山西煤改烧贵州煤后栲胶脱硫系统出现的问题及解决办法作一介绍.     

企业知识管理浅谈

随着知识经济的兴起和发展 ,知识管理将成为企业管理活动的主要领域。企业知识管理是企业组织整体对知识的获取、存储、学习、共享、创新的管理过程。本文主要探讨企业知识管理的内涵、基本内容以及企业如何实施知识管理     

日产1000t水泥熟料生产线的提产措施

通过对五级旋风筒下料管、回转窑转速、配料方案、物料稳定等四方面进行改进,达到提产目的。     

Water bamboo husk reinforced poly(lactic acid) green composites

The water bamboo husk is one of major agricultural wastes in Taiwan. In this study, the powder obtained from the water bamboo husk was added to poly(lactic acid) (PLA) to form novel reinforced biodegradable composites. Morphologies, mechanical properties, and heat resistance of these water bamboo powder reinforced composites were investigated. The results indicate that the char yields were increased as plant powder was incorporated to PLA. In addition, the mechanical properties were also enhanced due to the addition of powders. The increments of storage moduli of PLA were about 50–200%. Moreover, the increments of loss moduli of PLA were about 70–200%. On the other hand, the T_g of PLA was slightly decreased by the addition of powder, and this may improve the brittle characteristics of PLA. Furthermore, this type of reinforced PLA would be more environmental friendly than the artificial additive‐reinforced one. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers