CONTRIBUTION OF MACROSCOPIC DIMENSION EFFECT TO PIEZOELFCTRICITY IN POLYVINYLIDENE FLUORIDE

In this paper, we have studied the piezoelectricity in the poled uniaxially drawn polyvinylidene fluoride. The piezoelectric constants d_(31), d_(32), d_(33)~αand Young's moduli 1/s_11 and 1/s_(22) have been determined as a function of the remanent polarization Pr. The piezoelectric constants of the samples show a strong in-plane anisotropy. Such an anisotropy is mostly attributable to different Poisson's ratio. It is found that the piezoelectric activity mainly arises from macroscopic dimensional change.     

新型无毒离子液体催化“一锅煮”合成3,4-二氢嘧啶-2(1H)-酮

利用新型无毒离子液体(BMImSac)作催化剂, 芳香醛、1, 3-二羰基化合物和尿素或硫脲三组分“一锅煮”合成了3,4-二氢嘧啶-2(1H)-酮. 与传统方法相比, 该法是一种操作简单、产率高、用时少的环境友好方法.     

一维链状1,8-萘二酸四核锌配位聚合物[Zn4(1,8-nap)4(4,4''-bipy)2·0.5en·H2O]n的合成、结构、热稳定性及发光性质

羧酸配位聚合物是金属离子与有机羧酸构造块通过配位键或其他分子间弱作用力经自组装而成的一维、二维、三维的聚合物.由于这些配位聚合物具有新颖的拓扑结构以及在功能材料方面的潜在应用,同时又由于羧酸配合物比较稳定,所以设计和调控特殊配位聚合物成了当前的研究热点[1～4].     

双嵌段共聚物薄膜介观结构的耗散粒子动力学模拟

采用耗散粒子动力学(Dissipative Particle Dynamics, DPD)方法模拟两平行平板间的双嵌段共聚物体系的介观结构. 模拟结果表明, 随板间距的增大, 体系分层数量的增加是不连续的, 在分层数量的增加过程中, 出现不规则结构的过渡区；聚合物链末端距随板间距的增大呈周期性振荡, 振荡幅度逐渐减小. 对模拟结果的分析表明：层状结构转变点与分层数量之间存在近似线性关系；层状结构转变点近似与共聚物链长的2/3次方成正比.     

刺乌头碱的提取与其氢溴酸盐的合成及表征

刺乌头碱;刺乌头碱氢溴酸盐;合成;提取;表征     

凝胶渗透色谱法测定聚丙烯腈共聚物分子量中宽分布校正法的应用

应用宽分布校正法对凝胶渗透色谱(GPC)进行了校正，将校正曲线用于聚丙烯腈(PAN)共聚物分子量的计算。对扣除色谱峰扩展效应前后的测试结果与乌氏粘度法测得的数据进行比较。结果表明，应用宽分布校正法时，必须扣除色谱峰扩展效应，才能得到较为准确的测试结果。     

石墨烯负载高活性Pd催化剂对乙醇的电催化氧化

以石墨粉为原料, 采用Hummers法液相氧化合成了氧化石墨(GO), 然后用化学一步还原制得石墨烯负载钯催化剂. X射线衍射(XRD)、透射电镜(TEM)表征表明, Pd在石墨烯载体上有较好的分散度, 粒径为3-5 nm. 电化学活性面积(EASA)、循环伏安(CV)、计时电流(CA)和计时电位(CP)等电化学测试表明, 与传统Pd/Vulcan XC-72相比, Pd/石墨烯催化剂对碱性介质中乙醇电催化氧化的催化活性有了很大的提高.     

苯酚和草酸二甲酯在不同分子筛催化下的酯交换反应

研究了以TS－1、H－ZSM－5、Hβ和H－丝光沸石等不同分子筛为催化剂，苯酚和草酸二甲酯酯交换合成草酸二苯酯反应。通过对催化剂进行吸附吡啶的红外光谱和NH3－TPD表征，考察了不同分子筛催化剂的酸性和酸强度对草酸二苯酯合成反应的影响，确定了催化剂上的弱酸中心是催化苯酚和草酸二甲酯酯交换合成草酸二苯酯反应的活性位，且催化剂的酸性中心越多，酸量越大，催化活性越好。催化剂上的强酸中心促进了副产物苯甲醚的生成。     

Activation of bismuth(III) derivatives in ionic liquids: novel and recyclable catalytic systems for Friedel-Crafts acylation of aromatic compounds

The activity of four bismuth(III) derivatives when employed as Friedel-Crafts catalysts for the acylation of aromatics was found to increase dramatically when dissolved in ionic liquids. Solutions of bismuth oxide or triflate in [emim][NTf(2)] and [bmim][NTf(2)] are the most efficient catalytic systems, with catalyst loading as low as 1% leading to clean, high-yielding acylation of a variety of benzene derivatives. These improved Friedel-Crafts catalytic systems can also be efficiently recycled as opposed to traditional systems. [reaction: see text]     

Synthesis and mesomorphic properties of n-butyl-4- [4-((4-n-alkoxyl-tetrafluorophenyl)ethynyl)benzyloxy]benzoates

A homologous series of n-butyl-4-[4-((4-n-alkoxyl-tetrafluorophenyl)ethynyl)benzyloxy]benzoates have been synthesized.Their phase transition temperatures have also measured by polarizing textural observation and confirmed by DSC.