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.     

Control of stored grain pest, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) using the essential oil isolated from Plectranthus zeylanicus

The bruchid, Callosobruchus maculatus (F.) causes major losses during the storage of cowpea seeds [Vigna unguiculata (L.)Walp.] in Sri Lanka. Essential oil isolated from Plectranthus zeylanicus plant was tested for potential insecticidal activity against C. maculatus. The gas chromatography studies of the essential oil of P. zeylanicus showed that ρ-cymene (3.5%), β-caryophyllene (0.2%), geranyl acetate (9.3%) and geraniol (7.2%) were the major constituents. The adults of C. maculatus were susceptible to both fumigant and contact toxicity of P. zeylanicus plant oil. LC(50) values of 0.927 and 0.010?g?L(-1) were obtained for fumigant toxicity and contact toxicity assays, respectively. Oviposition and F(1) adult emergence were significantly inhibited by P. zeylanicus plant oil at a concentration higher than 0.001?g?L(-1) in both fumigant and contact toxicities. The analysis of olfactometer and choice camber bioassays revealed the repellent effects of the oil of P. zeylanicus plant.     

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...     

Komplexe von N,N-Di-(β-hydroxyäthyl)-dithiocarbaminat mit Übergangs- und Nachübergangs-Elementen

The complexation tendencies of N,N-di-(-hydroxyethyl)-dithiocarbamic acid [DEADTCH, (CH₂CH₂OH)₂NCSSH] towards a large number of metal ions have been examined. The complexes formed with transition and post-transition metal ions in slightly acidic and neutral solutions have the general formulaM(DEADTC) _x, wherex is the valence state of the metal,M=Cr(III), Fe(III), Co(III), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Tl(I), and Tl(III). In addition the interesting mixed ligand complex ClHg(DEADTC) was prepared. These complexes have been characterised through X-ray, magnetic, conductance and spectral (UV and IR) measurements.     

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.     

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     

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.     

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.