STRUCTURE SYNTHESIS OF 4-DOF PARALLEL ROBOT MECHANISMS BASED ON SCREW THEORY

Structural synthesis for 4-DOF parallel manipulators using screw theory is systematically studied. Motion properties and constraint conditions of 4-DOF parallel manipulators according to the relationship between screw and reciprocal screw are analyzed. Mathematical expressions for constraint screws and twist screws of moving platform are constructed, and all possible limbs, which provide one or more force constraints, are enumerated. Finally, a parallel manipulator with 3-rotation-DOF and 1-translation-DOF is used as an example to describe the synthesis procedure for symmetrical and non-symmetrical 4-DOF parallel manipulators.     

Size controlling of monodisperse carboxymethyl cellulose microparticles via a microfluidic process

Monodisperse carboxymethyl cellulose containing phenolic groups (CMC‐Ph) microdroplets with a radius of 100–400 μm and a coefficient of variation below 3% were produced in a coflowing microfluidic device. The CMC‐Ph solution containing horseradish peroxidase was used as the disperse phase and liquid paraffin containing H₂O₂ and lecithin as the continuous phase. The size of microdroplets decreased with the decreasing diameter of the inner channel and concentration of the disperse phase. When using a 0.04% CMC‐Ph solution and the device with the inner diameter of 160 μm, the size of the microdroplets can be further controlled by the flow rates of both the continuous phase and disperse phase following exponential models. The volume of the microdroplet was not inversely proportional to the flow‐rate ratio of the continuous phase to the disperse phase. There was a weak dependence of the volume on the flow of the continuous phase. The monodisperse microparticles possessed potential application for sensor, drug delivery system, cell encapsulation, catalysis, and imaging. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40663.     

建立基于Web的认证管理系统

主要阐述了如何建立基于Web的认证管理系统。通过中化阳光认证中心网站的建设,提出了认证管理网站建设的思路。在实施过程中,充分利用信息技术的成果,建立了后台数据库支持的信息发布系统和信息反馈系统,为建立适合中国国情的认证管理系统进行了有益的尝试。     

动态网络安全模型在石化企业的应用

在对石化企业网络安全现状和动态信息安全理论模型分析的基础上,讨论了动态网络安全模型在石化企业网络安全中的应用,论述了在网络安全这一复杂的系统工程中,安全管理和从事网络安全的人的作用。通过对动态网络安全模型的深入分析,提出了石化企业信息网络安全框架模型。并通过安全策略和危险权值的分析方法,实现了基于管理策略的动态网络安全模型在石化企业的应用。本文还就石化企业网络安全新技术的发展趋势进行了讨论。     

1，1＇-DM-5，5＇-AT和2，2＇-DM-5，5＇-AT热分解机理的量子化学研究

采用量子化学从头算方法全优化计算了1，1＇-二甲基-5，5’-偶氮四唑（1，1＇-DM-5，5’-AT）和2，2’-二甲基-5，5’-偶氮四唑（2，2’-DM-5，5’-AT）热分解反应位能曲线，探讨了它们的热分解机理。研究发现热分解按开环和脱氮两步完成，推测的机理可由取代四唑的热分解实验和理论研究所支持。计算得到1，1’-DM-5，5’-AT两步反应的活化能分别为243．5、64．01kJ／mol；2，2’-DM-5，5’-AT两步反应的活化能分别为152．3、44．67kJ／mol,二者的热分解活化能都表明开环反应是速度控制步骤。前者的两步反应的活化能均大于后者的活化能。从动力学性质显示前者比后者有更好的稳定性。