金属铜升温熔化过程的分子动力学模拟

采用分子动力学方法模拟了金属铜的升温熔化过程.原子间作用势采用FS (Finnis-Sinclair)势，结构分析采用双体分布函数(PCF)、均方位移(MSD)等方法.计算结果表明,在连续升温过程中，金属铜在1444 K熔化，在该熔化点的扩散系数为4.31×10－9 m2•s－1.上述结论与实验值相当接近，并且比之采用EAM镶嵌原子势所作模拟得到的结果更佳，说明FS势可以用来处理象液铜这样较复杂的无序体系.本文指出了升温速率在金属熔化过程中所起的作用.     

正烷酵母作为饲料的最近研究

本文叙述了近十年来我国对正烷烃酵母研究的进展。我们用的菌种是热带假丝酵母Y-17,本所实验厂的生产规模是年产一百吨酵母。发酵罐为6米~3的内或外循环空气提升式,两级连续发酵,50％废水循环利用。生产能力为2克/升·小时。酵母产品的化学分析,包括蛋白质、氨基酸、脂肪、核酸、维生素等,都证明该产品为一优良蛋白饲料。有毒物质含量(如苯骈(a)芘、重金属)符合国际标准。动物试验(包括用大白鼠、鸡、猪的营养试验,慢性毒性试验,传代试验)证明该正烷烃酵母为安全可靠的优良饲料。我们也研究了酵母的核酸和脂肪的综合利用、并筛选了一株高产新菌株球拟嗜烷烃酵母(新种)4B-2,使生产能力提高至2.8克/升·小时。     

微柱分离中的激光诱导荧光检测

 激光诱导荧光检测 (LIFD)以其高的灵敏度和选择性而被广泛应用于微柱分离技术中。以检测池为轴线 ,概述了激光诱导荧光检测系统新进展及其应用。引用了 5 2篇文献     

Dynamic Lie algebraic formulation of second‐order optical nonlinearity for substituted benzenes

A dynamic Lie algebraic (DLA) formulation is applied to the study of nonlinear optical properties of the substituted benzenes. We have described the generation of the dynamic Lie algebra for the model Hamiltonian used in the present study. In terms of these elements of the dynamic algebra we express the evolution operator as a function of the group parameters, which can be determined by means of solving a system of coupled nonlinear differential equations. Thus, in terms of the density matrix operator formalism in statistical mechanics we obtain the statistical averages of the electric polarization and then derive readily an expression for the hyperpolarizability of the paradisubstituted benzenes. Comparisons with experimental observations and other quantum calculations of the hyperpolarizabilities for the paradisubstituted benzenes are made qualitatively and quantitatively. These results imply that the DLA method appears useful in describing the nonlinear optical phenomena in the substituted benzene molecules. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 335–343, 2003     

Selective oxidation of isobutane over Mo-V-Te mixed oxide catalysts with different tellurium contents

A series of MoV_0.3Te_x (x = 0−0.3) mixed oxides were prepared and investigated for the selective oxidation of isobutane. Among them, MoV_0.3Te_0.23 showed the best methacrolein and methacrylic acid selectivity (as high as 17% and 16%, respectively), and the yield to methacrolein and methacrylic acid reached 3.6% and 3.5%, respectively, at 21.3% isobutane conversion at 440°C.     

Novel dual inhibitors against FP-2 and PfDHFR as potential antimalarial agents: Design,synthesis and biological evaluation

A series of novel 2,4-diaminopyrimidine-modified compounds was designed and synthesized. Compound 14 showed micromolar dual inhibitory effect on both FP-2 and PfDHFR, and potential inhibition to the proliferation of P. falciparum 3D7 strain and chloroquine-resistant P. falciparum Dd2 strain.     

Nucleosides. Part LX. Synthesis and Characterization of Monomeric Cordycepin-Vitamin and Cordycepin-Lipid Conjugates Model Substances for Biodegradable Ester and Carbonate Linkages in Conjugates and Potential Inhibitors of HIV-1 Replication

Monomeric 3′-deoxyadenosine (cordycepin) was modified at the 2′-O- ( 13–18 ) and 5′-O-position ( 25–29 ) by the vitamins E, D₂, and A and by the two lipids 1,2-di-O-palmitoylglycerol and 1,2-di-O-hexadecylglycerol via succinate or carbonate linkages. The base-labile conjugates afforded protection groups like the 2-(4-nitro-phenyl)ethoxycarbonyl (npeoc) and monomethoxytrityl group (MeOTr) that are cleavable without harming the ester and carbonate bonds, respectively. Monomeric conjugates of cordycepin and vitamin E, vitamin D₂, 1,2-di-O-palmitoylglycerol, and 1,2-di-O-hexadecylglycerol (see 13, 14, 17, 18, 25, 26, 28 , and 29 ) inhibited HIV-1-induced syncytia formation 1.7 to 6.2 fold compared to 1.5-fold for cordycepin (see Table); IC₅₀ values for 25 and 28 were 257 and 267 m?M , respectively. In addition, the monomeric cordycepin-vitamin and -lipid conjugates inhibited HIV-1 RT activity 28–49% which compares with a 13% inhibition of HIV-1 RT observed for cordycepin. The minimal inhibition of HIV-1-induced syncytia formation and HIV-1 RT activity did not proceed by the activation of RNase L. The monomeric conjugates tested ( 13, 14 ) increased PKR expression.     

胆汁酸的薄层层析——数理统计法用于层析溶剂系统的选择

本文选择氯仿、乙醇、乙酸乙酯、醋酸和水等五种溶剂作为胆汁酸薄层层析的展开剂,采用正交设计法[L_(16)(4~5)]安排实验,对胆固醇、胆酸、脱氧胆酸、甘氨胆酸、甘氨脱氧胆酸、牛磺胆酸、牛磺脱氧胆酸和卵磷脂等八种化合物的R_f值及层析谱斑点的集中情况,用直观分析和方差分析法处理,得到了单向一次薄层层析全部分离胆汁的溶剂系统,较文献报道方法为佳。     

室温离子液体EMIES的标准生成焓

在(298.15 ±0.01) K下用转动弹热量计测定了离子液体硫酸乙酯-1-甲基-3-乙基咪唑(EMIES)及合成它的原料1-甲基咪唑的恒容燃烧热,通过计算得到它们的标准燃烧焓 分别为(－2671±2) 和(－286.3±0.5) kJ·mol－1;标准生成焓 分别为(－3060±3) kJ·mol－1和(－2145±4) kJ·mol－1.结合文献上硫酸二乙酯的标准生成焓数据,得到了合成离子液体EMIES的反应热(－102.3±1.0) kJ·mol－1,与合成实验中观察到的强烈放热现象是一致的.根据离子液体EMIES的热容数据,计算了不同温度下EMIES的标准生成焓.     

Electronic structures of 4d transition metal monoxides by density functional theory

Bond distances, dissociation energies, ionization potentials and electron affinities of 4d transition metal monoxides from YO to CdO and their positive and negative ions were studied by use of density functional methods B3LYP, BLYP, B3PW91, BPW91, B3P86, BP86, SVWN, MPW1PW91 and PBE1PBE. It was found that calculated properties are highly dependent on the functionals employed, especially for dissociation energy. For most neutral species, pure density functionals BLYP, BPW91 and BP86 have good performance in predicting dissociation energy than hybrid density functionals B3LYP, B3PW91 and B3P86. In addition, BLYP gives the largest bond distance compared with other density functional methods, while SVWN gives shortest bond distance, largest dissociation energy and electron affinity. For the ground state, the spin multiplicity of the charged species can be obtained by ± 1 of their corresponding neutral species.