DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES

Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. “the second plateau“, appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature.     

Effect of TiO2 crystallite size on the dispersion of Co on nanocrystalline TiO2

Nanocrystalline TiO₂ powders with average crystallite sizes of 9–15 nm were synthesized by the solvothermal method and employed as supports for Co catalysts. The value of H₂ chemisorption/specific surface area of Co/TiO₂ increased significantly with increasing TiO₂ crystallite size. It was suggested that the higher amount of Ti³⁺ surface defects on the larger crystalline TiO₂ resulted in a stronger interaction between Co and TiO₂, hence, higher dispersion of Co was obtained.     

邻苯二甲酸Pb(Ⅱ)配合物纳米颗粒的合成及其燃烧催化性能研究

The nanoparticle Pb(Ⅱ)-Phtalate complex was synthesized by liquid dispersion deposition method using Pb(Ac)₂·3H₂O and potassium acid phthalate as the reactant. The nanoparticle complexes were characterized with TEM, XRD, TG, DSC and IR. The composition of the nanoparticle PbPht complex was determined by chemical and elemental analysis. The catalytic performance of nanoparticle complex on the combustion of RDX-CMDB propellant was investigated. The results showed the average particle size of complex were about 50 nm. The nanoparticle Pb(Ⅱ)-Phtalate complex can enhance burning-rate of propellant by 135%, and lower the pressure exponent by 74%.     

SYNTHESIS OF NEW HIGH MOLECULAR WEIGHT AND REACTIVE LADDERLIKE POLYSILSESQUIOXANES*

Ladderlike polychloropropylsilsesquioxane (CP-T) was first synthesized by "stepwise coupling polymerization".The molecular weight of CP-T is as high as 1.7×10~5. It is a tough, elastic reactive ladderlike polymer and has good heat-resistant and adhesive properties. CP-T can further react with many nucleophilic reagents to generate new ladderlike reactivepolysilsesquioxanes, which can be used as potential precursors in the synthesis of functional ladderlike polymers.     

以水热法于ZSM-5分子筛中分散MoO3的研究

热扩散法的ＭｏＯ３最高分散量为每克ＺＳＭ－５上０．０８克ＭｏＯ３．而本文采用水热分散法可使ＭｏＯ３在ＺＳＭ－５分子筛中的分散量大大提高．当分散量高达每克ＺＳＭ－５上０．３克ＭｏＯ３时，通过ＸＲＤ，ＩＲ，ＤＴＡ谱测试和吸附测定，都证实了ＭｏＯ３在ＺＳＭ－５中仍然是以非晶相分散态存在．此时，样品有吸附自重６％的水的吸附能力和相应的孔道．     

X-ray and neutron diffraction studies of the crystal and molecular structure of the predominant monocarboxylic acid obtained by mild acid hydrolysis of cyanocobalamin. Part I. X-ray diffraction studies of airdried crystals

The crystal structure of air-dried crystals of the O-monocarboxylic acid of cyanocobalamin, E2, has been solved by x-ray analysis. The lattice constants area =14-51 A,b = 1709 A,c = 16.35A, β = 103°; space group P2₁. Phase angles were derived from observations on anomalous dispersion effects for 2567 of the measured 2875 pairs of reflections,hkl andhkl, and used in the solution of the structure. The intensities of reflexions were eye estimated from Weissenberg photographs. The molecular arrangement is very different from that of other cyanocobalamins; the corrin rings of neighbouring molecules are atca 90° to one another. It was not possible to recognise the one acid group among the amides with certainty.     

用化学计量法—分光光度法测定活体叶片中叶绿素a,b的含量

本文研究了用逐步回归分析法、主成分回归法、偏最小二乘法与人工神经网络法测定活体叶片中叶绿素a、b的含量。活体叶片的光谱由PC微机采集,测定叶绿素a与b的相关系数分别达到0.927～0.958与0.873～0.908;相对标准偏差约5％～9％(叶绿素a 9.4μg/2ml,n=20)。本方法可用于农业研究。     

氧化物－NaZSM－5催化剂的研究 Ⅰ．ZnO－NaZSM－5催化剂的表征

氧化物－ＮａＺＳＭ－５催化剂的研究　Ⅰ．ＺｎＯ－ＮａＺＳＭ－５催化剂的表征杨民，徐柏庆，梁娟，盛世善（中国科学院大连化学物理研究所，大连１１６０２３；大连理工大学化工学院化学系，大连１１６０１２）关键词ＺＳＭ－５沸石，氧化锌，分散，强相互作用，表征在...     

氨基酸结构描述子矢量VHSE及其在肽QSAR中的应用

从20种天然氨基酸的50个物化性质出发，按照疏水、立体和电性特征将其分类后分别进行主成分分析，并将产生的得分矢量即VHSE(principal component score vector of hydrophilicity,steric，and electronic properties)作为氨基酸结构描述子用于肽的定量构效关系研究。与已有方法相比，VHSE描述子具有物化意义明确、结果更易解释等特点。应用该描述子并结合逐步回归变量筛选和偏最小二乘建模方法，在对苦味二肽和血管舒缓激肽促进剂等体系的定量构效关系研究中，均取得了优于已有文献的结果。