_f-A_aD_d氢键体系的统计特征

基于氢键的形成和缩聚反应机理在统计意义下的相似性,利用高分子反应统计理论和反应动力学理论对氢键溶液的一个模型体系进行了相关讨论.给出了体系的溶胶分数和发生溶胶-凝胶相变的条件,指出质子受体基团间的竞争作用对溶胶凝胶相变点的影响,进而讨论了体系的数量分布函数和相关问题.     

AB_3型超支化聚(酰胺-酯)的合成及缩聚动力学研究

采用丁二酸酐、三羟甲基氨基甲烷为主要原料 ,在冰水浴条件下 ,合成AB3型单体 ,然后进行熔融缩聚制得超支化聚 (酰胺 酯 ) ,没有出现凝胶现象 .采用Fourier变换红外谱仪 (FTIR)、粘度测试、端基分析等方法对其结构、特性粘数进行了表征 .同时对AB3型超支化聚 (酰胺 酯 )的缩聚反应动力学进行了研究 ,得出了130℃、14 0℃和 15 0℃时的缩聚反应速率常数 ,并进一步得出了缩聚反应活化能 .实验结果证明缩聚过程为自催化过程 ,且为三级反应     

阴离子型微乳液对火焰原子吸收法测铅增敏作用的研究与应用

研究了在空气－乙炔火焰中，阴离子型表面活性剂十二烷基硫酸钠（ＳＤＳ）组成的微乳液对铅原子化行为的影响。结果表明：在ＳＤＳ组成的微乳液存在下，铅的灵敏度提高了近６０％，比ＳＤＳ胶束存在下灵敏度也提高了２０％。方法用于黄铅和工业废水中铅的测定，结果令人满意。     

异质Stackelberg寡头竞争下创新产品技术许可策略研究

基于异质产品Stackelberg寡头竞争模型,建立了拥有新产品创新技术在位厂商与潜在竞争对手间的技术许可博弈模型.模型中假设潜在竞争对手可以接受许可,也可通过自我研发创新技术进入市场参与竞争.根据潜在竞争对手研发成本的高低,研究了创新厂商的最优两部制收费策略.研究结果表明:潜在竞争者总会接受创新技术许可,最优许可策略依赖于研发成本、市场参数以及产品的替代系数.     

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     

Crystal and electronic structure of Ni3Bi2S2 (parkerite)

The crystal structure of parkerite, Ni₃Bi₂S₂, was studied by single-crystal X-ray diffraction analysis and refined. The single crystal was prepared by the method of chemical transport reactions. The electronic structure of Ni₃Bi₂S₂ was calculated by the extended Hückel and DFT--LMTO--ASA methods. Substantial delocalization of electrons in the vicinity of the Fermi level and the presence of the strong Ni--S and Ni--Bi bonds were revealed. The Ni--Ni bonds are weak, which is in agreement with the X-ray diffraction data.     

New polymolecular bismuth monohalides. Synthesis and crystal structures of Bi4BrxI4–x (x = 1, 2, or 3)

New mixed bismuth monohalides Bi₄Br_xI_4–x (x = 1, 2, or 3) were prepared for the first time by the reactions of bismuth metal with bismuth trihalides taken in stoichiometric amounts. Their crystal structures were established by single-crystal X-ray diffraction analysis. The Bi₄Br₃I and Bi₄BrI₃ compounds are isostructural and crystallize in the orthorhombic system, and Bi₄Br₂I₂ crystallizes in the monoclinic system. The crystal structures of all three phases contain one-dimensionally infinite molecular chains consisting of the [Bi₄X₄] fragments whose structures are identical with those of the individual Bi₄I₄ and Bi₄Br₄ molecules. The molecules are packed in layers. Different packing modes of the layers were found for different bismuth monohalides. The Bi₄ClI₃ compound, which is apparently structurally similar to Bi₄Br₃I and Bi₄BrI₃, was also prepared.