4A分子筛合成中原料配比的影响

水热合成 4A分子筛过程中 ,原料的配比对合成分子筛的种类及纯度有极大影响 ,进而影响 4A分子筛的钙离子交换能力、吸水能力等理化性能。合成原料的配比发生改变 ,产品4A分子筛中会分别含有羟基方钠石、B型分子筛等杂相 ;控制好原料配比 ,可以得到纯 4A分子筛、纯 B型分子筛、纯 X型分子筛     

高酸性ZrMCM-41分子筛的合成和表征

以硅酸钠为硅源、以硝酸氧锆为锆源 ,在接近中性的条件下合成出了Si/Zr比 2 0～∞的 ,具有高比表面和良好晶体性的含锆MCM - 41分子筛 .锆的引入使分子筛的B酸和L酸线性增加 .至少有大约三分之一的锆原子以 [(≡Si-O) 3Zr=O]-的形式处在表面或接近表面 ,在合成样品中它由钠离子补偿 ,经氢离子交换转变成酸性中心 .     

可溶性聚合物支载下合成小分子化合物

概述了液相合成中使用的可溶性聚合物性质和特点,以及可溶性聚合物支载下小分子化合物的合成和可溶性聚合物支载的催化剂、氧化剂和还原剂在合成小分子化合物中的应用。     

链烷烃分子结构表征及其热力学函数的估算

基于分子结构的两种最基本的特性－原子间距离和原子的连接关系,提出了分子距离－连接性矢量（MDC）,以其表征化合物的分子结构,并对2－9个碳原子饱和烷烃共74个分子的两种重要的热力学函数（原子化热和蒸发热）进行了定量构效关系研究,结果表明新的距连知音一具有结构选择性高、性质相关性好的特点,而且计算较简便。     

关于双原子分子转动配分函数的讨论

该文就热力学统计物理教材中仲氢分子配分函数的表达式提出了不同看法,并给出了修改建议。     

煤表面与高分子作用机理的量子化学研究

选择不同煤阶的煤分子结构模型,结合量子化学方法,对煤分子中各原子的电子去分布进行计算,根据计算结果,分析了高分子在煤粒表面的吸附机理,解释阴离子型高分子在带负电的煤粒表面的吸附原因。     

Molecular tagging of a genic male-sterile gene in rice

The sterility of Pingxiang male-sterile rice (Pms), possibly derided from a spontaneous mutation in Pingxiang fertile rice (Pmf), was previously reported to be controlled by a single dominant nuclear gene. It can be restored to fertility either by a dominant epistatic gene or by higher temperature treatment at the early stage of inflorescence development. In order to tag the genic male-sterile gene, Pms, Pmf and Ce 64, a cytoplasmic male-sterile restoring line without the epistatic gene for Pms, were used to construct mapping populations. Two segregation populations, “(Pms/Ce 64) F1s (sterile plant)//Pmf ” F1 and “Pms//(Pmf/Ce 64) F1” F1, were simultaneously developed. Subsequently, the genic male- sterile gene was mapped between a simple sequence length polymorphism marker, RM228, and a restriction fragment length polymorphism marker, G2155, with distances of 14.9 and 2.6 cM, respectively. The tagged dominant genic male-sterile gene is temporarily designated Ms-p.     

Mapping of two new brown planthopper resistance genes from wild rice

A brown planthopper (BPH) resistance line, B5, derived its resistance genes from the wild riceOryza officinalis Wall exwatt, was hybridized with Taichung Native 1, a cultivar highly susceptible to BPH. A mapping population composed of randomly selected 167 F₂ individuals was used for determining the BPH resistance genes by the restriction fragment length polymorphism analysis (RFLP). Bulked segregant analysis was conducted to identify RFLP makers linked to the BPH resistance genes in B5. The results indicated that the markers linked to BPH resistance are located at two genomic regions on the long arm of chromosome 3 and the short arm of chromosome 4, respectively. The existence of the two loci was further assessed by the quantitative trait locus (QTL) analysis. We located the two loci at a 3.2 cM interval between G1318 and R1925 on chromosome 3 and a 1.2 cM interval between C820 and S11182 on chromosome 4. Comparison with the BPH genes that have been reported indicated that the BPH resistance genes in B5 are novel. These two genes may be useful BPH resistance resource for rice breeding. Furthermore, the mapping of the two genes is useful for cloning the BPH resistance genes.     

Molecular dynamics simulations on specific heat capacity and glass transition temperature of liquid silver

The embedded-atom method is adopted to simulate the specific heat capacity of liquid silver. The relationship between the specific heat capacity and the temperature above and below melting point is derived. The results show that there exists an anormaly of the specific heat capacity of liquid silver near 950 K. Simulated pair distribution functions show that the liquid-to-glass transition takes place at this temperature.     

Electronic structures and infrared spectra of C120O2, C120OS and C120S2

Electronic structures and infrared spectra of C₁₂₀XY molecules (X, Y=O, S) and some of the corresponding ions are investigated using PM3 semi-empirical molecular orbital calculations with full optimization of geometrical structures. It is found that the energy penalty is about 30–42 kJ/mol due to introducing a double bond in the fivemembered ring except for C₁₂₀O₂ ⁻ and triplet C₁₂₀O₂ ²⁻. It is also found that the structures of neutral molecules and the corresponding ions are almost the same; for instance, the change of bond length is less than 0.001 nm. The change of frontier orbits from oxide to sulfide is little as well. The triplet states of C₁₂₀O₂ ²⁻ and C₁₂₀OS²⁻ are more stable than their singlet states, which means that C₁₂₀O₂ ²⁻ and C₁₂₀OS²⁻ follow the Hund’s rule. The vibration analysis showed that the infrared spectra of neutral C₁₂₀O₂ and C₁₂₀OS molecules are in good agreement with the experimental results. Compared with the neutral molecule, vibration frequencies of triplet C₁₂₀O₂ ²⁻ change little, but the vibration intensities are enhanced obviously.