养护条件对UHPC强度和毛细吸水性的影响

为优化超高性能混凝土(UHPC)预制构件养护工艺,研究了不同养护条件对UHPC强度和毛细吸水性的影响,并采用孔结构测试、热重分析和扫描电镜观察,对其机理进行了分析.结果表明:热养护显著提高了UHPC的7 d强度,这与加速火山灰反应有关,但高温和干热养护对其后期强度增大不利,甚至出现约3％的强度倒缩;不论何种养护,UHP...     

Statistical theory for hydrogen bonding fluid system of AaDd type (Ⅲ): Equation of state and fluctuations

The equation of the state of the hydrogen bonding fluid system of AaDd type is studied by the principle of statistical mechanics. The influences of hydrogen bonds on the equation of state of the system are obtained based on the change in volume due to hydrogen bonds. Moreover, the number density fluctuations of both molecules and hydrogen bonds as well as their spatial correlation property are investigated. Furthermore, an equation describing relation between the number density correlation function of "molecules-hydrogen bonds" and that of molecules and hydrogen bonds is derived. As application,taking the van der Waals hydrogen bonding fluid as an example, we considered the effect of hydrogen bonds on its relevant statistical properties.     

纤维改性硫氧镁基仿木保温材料性能研究

为了提高硫氧镁基仿木保温材料的各项性能, 分别研究了相同长度的聚丙烯纤维(PPF)、聚乙烯醇纤维(PVAF)、玻璃纤维(GF)对其性能的影响. 结果表明: 随着纤维掺量的增加, 硫氧镁基仿木保温材料的流动性有所降低; GF对其抗压抗折强度的提高效果最明显, 其中GF掺量为1.0 kg·m^-3时早期抗压强度最高, PVAF掺量为0.5 kg·m^-3时其早期抗压强度最高; PPF明显提高了硫氧镁基仿木保温材料的耐水性, 其掺量为0.5 kg·m^-3时软化系数最大, 而GF掺量在1.0 kg·m^-3时, 浸水软化系数稍高于未加纤维的对比试件; 掺加PVAF后硫氧镁基保温材料的导热系数出现一定程度的降低, 其中PVAF掺量在1.5 kg·m^-3时其导热系数最低. GF和PPF可以明显地降低硫氧镁基仿木保温材料的收缩值, 其中GF降低自收缩效果较好, 而PPF可以明显地降低其干燥收缩值.     

茂钇-铝双金属配合物催化甲基丙烯酸甲酯立规聚合

立规聚合;茂稀土催化剂;稀土;茂钇-铝双金属配合物催化甲基丙烯酸甲酯立规聚合     

烯烃聚合高性能FI催化剂的进展

FI催化剂系一近几年发展起来的烯烃聚合高性能催化剂。以它的极高的活性、聚合物分子结构的可控性、多重活性聚合等特性而引人注目。本评述首先进行该催化剂的化学描述,然后分别介绍该催化剂的主要特征、活性中心结构、聚合机理和应用,重点介绍该催化剂的五大特征。     

Statistical theory for hydrogen bonding fluid system of A_aD_d type (I): The geometrical phase transition

The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.     

光场横向效应导致CO2激光器混沌运转的实验研究

对横向效应导致单纵模多横模CO_2激光器失稳进行了实验研究.观测到了经各种途径到达的激光混沌态,并对其物理机制进行了探讨.     

ICP-AES法测定蒙药紫癜灵中多种微量元素

蒙药含有多种氨基酸和丰富的微量元素,特别是人体必需的微量元素含量相对较高,而对人体有害的重金属元素含量相对较低。采用微波消解ICP-AES法同时测定了治疗过敏性紫癜的蒙药紫癜灵中Ca, Mg, Sr, Fe, Mn, Zn, Cu和Pb等15种微量元素。紫癜灵的临床药效实验,选择了过敏性紫癜患者260例,其中男性140例,女性120例;年龄最小6岁,最大62岁,6～16岁年龄段最多,占病人总数的90%左右。治疗结果显示：治愈234例,占90%;显效13例,占5%;有效11例,占4.23%;无效2例,占0.77%;总有效率达99.23%。紫癜灵中含有丰富的微量元素,尤其锶的含量相当高。方法的加标回收率在94.63%～106.40% 之间,相对标准偏差RSD≤3.17%,检出限≤0.009 μg·L-1。     

Af型自由基均聚反应的固化理论(Ⅲ)──高分子凝胶网络缺陷

应用高分子反应统计理论,分析了高分子网络的形成过程,讨论了A_f型自由基均聚反应凝胶网络中的缺陷悬吊环的数目及其形成几率.