Synthesis and properties of new polyamides based on a hydroxyethyl cinnamide extended from 3,5‐diaminobenzoic acid

A series of new aromatic polyamides containing cinnamide pendent units were prepared from 2′‐(cinnamide)ethyl‐3,5‐diaminobenzoate and various aromatic dicarboxylic acids by the direct polycondensation reaction, with triphenyl phosphite and pyridine as condensing agents. The polyamides were characterized by ¹H NMR, IR, and UV spectroscopy, and gel permeation chromatography. Their thermal stability was studied by thermogravimetric analysis in air, and differential scanning calorimetry. These polymers were readily soluble in polar aprotic solvents and can be cast from their solutions in flexible and tough films. Glass transition temperatures (T_gs) of these polyamides were observed in the range of 225–245°C. Their inherent viscosities varied from 0.77 to 1.12 dL/g that corresponded to weight–average and number–average molecular weights of 39,000–72,700 and 18,800–29,000, respectively. These polymers can be photochemically crosslinked. The photochemical aspects were revealed by means of UV–vis and IR analyses onto thin films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2013–2020, 2007     

Tri-pyramid Robot: Design and kinematic analysis of a 3-DOF translational parallel manipulator

3-DOF translational parallel manipulators have been developed in many different forms, but they still have respective disadvantages in different applications. To overcome their disadvantages, the structure and constraint design of a 3-DOF translational parallel manipulator is presented and named the Tri-pyramid Robot. In the constraint design of the presented manipulator, a conical displacement subset is defined based on displacement group theory. A triangular pyramidal constraint is presented and applied in the constraint designs between the manipulator?s subchains. The structural properties including the decoupled motions, overconstraint elimination, singularity free workspace, fixed actuators and isotropic configuration are analyzed and compared to existing structures. The Tri-pyramid Robot is constrained and realized by a minimal number of 1-DOF joints. The kinematic position solutions, workspace with variation of structural parameters, Jacobian matrix, isotropic and dexterity analysis are performed and evaluated in the numerical simulations.     

Ⅱ型B族链球菌表面免疫相关蛋白基因的克隆和原核表达

目的重组表达Ⅱ型B族链球菌表面免疫相关蛋白(Surfaceimmunogenicprotein,SIP)基因,为进一步免疫学研究提供目标蛋白。方法用PCR的方法从GBSⅡ型标准株的基因组DNA中扩增出SIP基因,用T/A克隆法将其插入pMD18T载体,构建原核表达载体pET32aSIP,用BL21(DE3)/pET系统表达TrixSIP融合蛋白,SDSPAGE和质谱分析鉴定表达产物,并对表达蛋白进行初步纯化。结果PCR扩增产物经测序,证实与GenBank中Ⅰa/c型GBS的SIP的基因序列同源性为99%。SDSPAGE显示,经IPTG诱导后BL21(DE3)/pET32aSIP总蛋白中出现一条相对分子质量为66000的新蛋白带。质谱分析和蛋白质库的比较证实其为B族链球菌表面免疫相关蛋白(SIP)的可能性分数为74。结论已成功表达并初步纯化SIP,为SIP在细菌致病中的作用研究以及相关疫苗的制备奠定了基础。     

基于Monte Carlo随机模拟的综合交通网络布局评价与决策方法

针对综合交通网络评价指标权重及属性值具有主观性和随机性的特点,提出了基于模拟运算的布局规划方案排序选优的群体随机决策方法.仿真生成满足集结的多个专家对指标重要性偏好排序统计分布的权重,同时考虑交通需求的不确定性对指标值的影响,结合客观熵权计算方案的综合评价值,由多次模拟得到的排序优势度确定方案的优劣差异.根据设计的仿真流程通过算例说明了方法应用的有效性,评价中考虑了主客观因素及随机性特征,可以为网络布局提供科学决策依据.     

面向在线社区用户的群体推荐算法研究

结合现有两种主要群体推荐算法的优势, 建立新的算法框架, 并引入差异度因素对模型进行优化。另外, 考虑到在线社区用户的特点, 定义互动度指标来描述群体成员间的互动程度, 通过分析其与推荐精度之间的关系, 探讨互动度对群体推荐的影响。选取豆瓣网数据进行实验, 并与传统方法进行比较, 结果表明, 融入差异度的算法具有更好的推荐效果, 且有效的互动机制能够保证较高的推荐精度。     

基于一致性的小型四旋翼机群自主编队分布式运动规划

设计一种小型四旋翼无人机群起飞后自主形成正多边形编队的分布式运动规划方法.在四旋翼无人机的串级控制系统框架下,分布式编队控制器以简化agent模型为基础,同时采用平均一致性算法和有领导一致性算法,共同产生各无人机位置与偏航角的期望轨迹.讨论了达成最终协调目标队形的拓扑条件,并给出一种基于有向Hamilton环的通信拓扑设计方案.最后通过数值仿真验证了所提出算法的有效性.     

硫化机网络群控系统

对硫化机群采用分散控制-集中管理式中央监控系统.系统分底层网络和上层网络两部分.底层网络分二级控制,采集现场硫化机温度、压力等参数.上层网络用于对生产数据进行处理显示、打印报表等.各层控制系统实现相对独立,该系统运行多年,未发生异常现象.     

A群脑膜炎球菌多糖菌苗的接种反应及血清学效果

本文对A群脑膜炎球菌多糖菌苗不同剂量、针次和不同年龄儿童接种后反应及血清学效果进行了研究。根据上海市区和山东青州市儿童接种一般反应以及青州市10万余名儿童接种后异常反应观察表明,接种50μg和30μg菌苗后的反应都是很轻微的,但3岁以下婴幼儿的接种反应高于7岁儿童。3岁以下婴幼儿中强体温反应,50μg高于30μg;两种剂量菌苗接种后的免疫应答相似,接种2针后的杀菌抗体水平高于1针,13～24月龄幼儿接种后的杀菌抗体水平明显高于6～12月龄婴儿,但均低于7岁儿童。     

直纺长丝工艺中聚酯熔体端羧基值控制的工业研究

本文从工业生产的实践出发对杜邦聚酯技术直接纺工艺中端羧基控制进行了研究。通过对熔体端羧基值对无油长丝端羧基、粘度及纺丝加工影响的分析 ,阐明了聚酯端羧基控制范围 ;通过摸索三个反应釜工艺条件对端羧基值的影响 ,找出了端羧基工业控制的有效途径 ,为同类技术装置生产提供了依据     

丙烯酸型亲水涂料乳胶粒表面羧基分布的研究

研究了以苯乙烯为核,丙烯酸酯类为壳的核壳乳液,采用丙烯酸为功能性单体,成膜后羧基为极性基团分布在涂膜表面达到亲水目的。讨论了功能单体丙烯酸(AA)在乳胶粒表面的分布情况及其加量对涂膜亲水性的影响,通过电导滴定发现当AA的加入量为3%时,水相中游离的丙烯酸含量为5.57%,聚合物表面的羧基含量为36.11%,涂膜的亲水性达到最佳,水接触角为51.1°。本文还讨论了核壳法和核壳翻转法对乳胶粒表面羧基分布及涂膜亲水性能的影响,两者的电导滴定曲线形状一致,由两个当量点可以计算出水相中游离的丙烯酸含量为1.47%,而乳胶粒表面羧基分布的含量为43.59%,可见,用核壳翻转法合成的乳液,乳胶粒表面羧基分布含量比普通聚合方法合成的乳胶粒表面羧基分布含量高,涂膜亲水性进一步提高,水接触角降低为44.5°。