Genetic analysis and molecular mapping of a presenescing leaf gene psl1 in rice (Oryza sativa L.)

A rice psl1 (presenescing leaf) mutant was obtained from a japonica variety Zhonghua 11 via radiation of 60Co-γ in M2 generation. Every leaf of the mutant began to wither after it reached the big-gest length,while the leaves of the wild variety could keep green for 25―35 d. In this study,genetic analysis and gene mapping were carried out for the mutant identified. The SSR marker analysis showed that the mutant was controlled by a single recessive gene (psl1) located on chromosome 2. Fine mapping of the psl1 locus was conducted with 34 new STS markers developed around psl1 anchored region based on the sequence diversity between Nippon-bare and 93-11. The psl1 was further mapped be-tween two STS markers,STS2-19 and STS2-26,with genetic distances of 0.43 and 0.11 cM,respectively,while cosegregated with STS2-25. A BAC contig was found to span the psl1 locus,the region being delim-ited to 48 kb. This result was very useful for cloning of the psl1 gene.     

分子马达偶极子模型的构造基础

介绍了构造分子马达偶极子模型的生物学基础、物理学模型及相互作用势。     

MOLECULAR CHAIN STRUCTURE AND CRYSTALLINE STRUCTURE OF PB-ET COPOLYESTER

The molecular chain structure and crystalline structure of PB-ET copolyester made by con-densation polymerization are studied by means of ~(13)C nuclear magnetic resonance spectroscopy(~(13)C NMR),dynamic mechanical analysis (DMA),wide angle X-ray scattering (WAXS),depolarized light intensity (DLI) and stress-strain measurement(S-S).It is shown that PB-ETcopolyester is a random copolymer.Because of different ratios of EG(ethylene glycol)to BD(butane diol)in the copolyester,its crystalline forms and mechanical properties vary remarkably.With the increasing amount of BD,its crystallization kinetic parameters n,k and t_(1/2)~(-1) increaserapidly.When EG/BD equals 25/75 (mole ratio),the copolyester has αβ transition as PBTdoes.     

用微振动理论确定分子的力常数

把分子的振动视为一种无阻尼自由振动．采用分析力学的方法，求出分子振动的简正频率，从而确定分子的力常数．     

饱和烷烃的热力学性质与分子结构的拓扑相关性研究

根据拓扑学原理,运用图论方法,以计算机为工具,对饱和烷烃的分子结构信息进行处理,定义了一个表征分子结构信息的内聚力指数Ｆ,并和拓扑指数,Ｗ,Ｐ一道,应用于微观结构与物性关系的研究之中,与饱和烷烃的热力学性质进行关联拟合,给出了相 的定量关系式,利用所得公式能够直接由分子结构信息预测饱和烷烃的热力学性质。     

密度泛函理论方法研究稀土-过渡金属化合物的磁性和自旋密度图

Magnetic coupling constants J for the complete structures of rare earth\|transition metal compounds:LGdCu(NO\-3)\-3·Me\-2CO(1,Gd(Ⅲ)Cu(Ⅱ)) and [Ce(C\-4H\-7ON)\-4(H\-2O)\-3][Cr(CN)\-6]·2H\-2O(2, Ce(Ⅲ)Cr(Ⅲ)) have been calculated by the combination of the broken\|symmetry approach with the spin project method under the DFT framework.The J value for 1 is a small number in absolute value -2 4cm -1 for calculation,3 5cm -1 for experimental measurement.The spin density distributions are in detail discussed on the basis of Mulliken population analysis,taking into account the coexistence of spin delocalization and spin polarization mechanisms.For 1,the spin distribution in the ground state may be understood as a result of the competition between two mechanisms:a spin delocalization from Cu(Ⅱ) and a spin polarization of Gd(Ⅲ),and the former is dominant.In the case of 2,both transition metal Cr(Ⅲ) and rare earth Ce(Ⅲ) display a spin polarization effect on the surrounding atoms,where a counteraction of the opposite polarization effects leads a low spin density on the bridging ligand C1N1.In the ground state of 2,the stronger polarization effect of Cr(Ⅲ) even causes the positive spin density on the adjacent bridging atom N1.     

二聚炔雌醇分子钳对氨基酸的对映选择性识别

利用人工受体与适当底物间的分子识别 ,以建立仿生模型的研究已成为生物有机化学前沿富有挑战性的领域之一 [1 ] .生物分子多数是手性分子 ,因而手性识别在生命过程中极其重要[2 ] .近年来对氨基酸的手性识别引起了广泛的兴趣 .多种大环受体 (如冠醚、环糊精、环番等 )对氨基酸的手性识别有较多的报道 ,然而甾体类大环和甾体分子钳受体对氨基酸的手性识别报道却很少 .我们曾报道了二聚雌二醇分子钳 ( 1 ,2 ,3,4)对氨基酸具有对映选择性识别性能[3,4] .这里报道由炔雌醇构筑的分子钳 ( 5 ,6 ,7,8)对氨基酸的手性识别 ,并与雌二醇分子钳的识别…     

用连接性指数研究苯砜基环烷酸酯的容量因子

运用Matlab程序计算了28种苯砜基环烷酸酯类化合物的8种价分子连接性指数,并对这些化合物进行定量结构色谱保留相关性(QSRR)分析。通过多元统计的逐步回归建立了QSRR模型,其计算误差应接近实验误差。该模型经逐一剔除法检验具有良好的稳定性、可靠性及预测能力。     

接枝SAN分子量对ABS树脂性能和形态结构的影响

采用种子乳液聚合法在聚丁二烯乳胶粒上接枝共聚苯乙烯和丙烯腈、通过改变共聚单体中叔十二烷基硫醇（TDDM）的用量,合成了一系列PB-g-SAN共聚物,将这些共聚物与SAN树脂熔融共混制得了ABS树脂,研究了单体中TDDM含量对SAN在PB上的接枝率、SAN的分子量及ABS树脂的性能和形态结构的影响,结果发现,SAN在PB上的接枝率及其分子量随TDDM含量的增加而下降,在单体中无TDDM时,PB-g-SAN共聚物的增韧效果变差导致了ABS村脂的冲击强度较低,引入TDDM后明显地改善了ABS树脂的冲击韧性和加工性能。形态结构研究结果表明,单体中TDDM的含量显著地影响着PB橡胶粒子的内部结构,随着TDDM含量的增加,橡胶粒子中SAN包容结构的尺寸增大。