3，5-二甲基苯溴化镁修饰的ZSM-5催化剂乙苯歧化反应

采用尺寸较大的有机分子格式试剂（3,5-二甲基苯溴化镁）修饰ZSM-5催化剂,用乙苯歧化反应研究了修饰催化剂的择形性,并利用探针分子动力学扩散测试结合探针分子吸附红外等手段研究分子筛孔径和内外表面酸性性质等。结果表明,少量的3,5-二甲基苯溴化镁精确地中和了ZSM-5分子筛外表面的酸性中心,导致乙苯歧化反应中极高的对二乙苯选择性。而探针分子动力学结果表明,这种修饰并未引起分子筛孔道结构的变化。     

Thermal decomposition,kinetic study and evolved gas analysis of 1,3,5-triazine-2,4,6-triamine

The thermo-physical properties for four rock types (granite, granodiorite, gabbro, and garnet amphibolite) from room temperature to 1,173 K were investigated. Thermal diffusivity and specific heat capacity were measured using the laser-flash technique and heat flux differential scanning calorimetry, respectively. Combined with the density data, rock thermal conductivities were calculated. Rock thermal diffusivity and conductivity decrease as the temperature increases and approach a constant value at high temperatures. At room temperature, the measured thermal conductivity is consistently near or lower than the calculated conductivity using the mineral series model, which suggests that real thermal conduction is more complicated than is depicted in the model. Therefore, in situ measurement remains the best method for accurately obtaining thermal conductivity for rocks.     

Selectfluor and NFSI exo‐Glycal Fluorination Strategies Applied to the Enhancement of the Binding Affinity of Galactofuranosyltransferase GlfT2 Inhibitors

Two complementary methods for the synthesis of fluorinated exo‐glycals have been developed, for which previously no general reaction had been available. First, a Selectfluor‐mediated fluorination was optimized after detailed analysis of all the reaction parameters. A dramatic effect of molecular sieves on the course of the reaction was observed. The reaction was generalized with a set of biologically relevant furanosides and pyranosides. A second direct approach involving carbanionic chemistry and the use of N‐fluorobenzenesulfonimide (NFSI) was performed and this method gave better diastereoselectivities. Assignment of the Z/E configuration of all the fluorinated exo‐glycals was achieved based on the results of HOESY experiments. Furthermore, fluorinated exo‐glycal analogues of UDP‐galactofuranose were prepared and assayed against GlfT2, which is a key enzyme involved in the cell‐wall biosynthesis of major pathogens. The fluorinated exo‐glycals proved to be potent inhibitors as compared with a series of C‐glycosidic analogues of UDP‐Galf, thus demonstrating the double beneficial effect of the exocyclic enol ether functionality and the fluorine atom.     

利用超声相干技术在室温和高压下研究几种不同性能的玻璃

 综合使用超声相干技术几种不同的测量方法，分别研究两类三种不同性能的玻璃材料，测量它们的声速和衰减在室温及高压条件下的变化规律。结果表明：两类玻璃的声速和衰减以及由此而得到的弹性常数存在较大差异。两种硅玻璃在高压下，声速随压力变化的规律相似，压力升高时，纵波速度随之单调增加，横波速度线性减少，纵波衰减也随压力升高呈增加趋势。不同的是：两种玻璃横波衰减随压力的变化规律完全相反，水白玻璃的衰减增加，窗口玻璃的减小。上述几种方法的测量结果基本一致，且在相应的压力范围内与布里渊散射的实验结果基本吻合。     

Convenient preparation of optically active N,N-bis(4-substituted-4-aminobutyl)amines

An efficient and convenient method for the synthesis of chiral triamines with two substituents at the α position to the terminal amino group (spermidine analogues) is described. These chiral N,N-bis(4-substituted-4-aminobutyl)amines may have anticancer activities.     

层状半导体WSe2的电子结构和各向异性光学性质研究

采用第一性原理密度泛函理论研究了六角层状晶体 WSe2 的电子结构和各向异性光学性质. 结果表明:WSe2 为间接带隙半导体, 带隙值为1 .44 eV, 略小于实验值(1 .51 eV) ; 价带和导带均主要由 W-5d 和Se-4p 电子构成, 在价带顶(0~2eV) 及导带底(1 .5 ~3.5 eV) , W-5d 和 Se-4p 电子杂化明显, 形成共价键. 介电函数的虚部和实部均表现出明显的各向异性,εi (xx ) 有一个明显的介电吸收峰, 而εi (zz ) 却有两个明显的介电吸收峰; WSe2 晶体对zz 光的低频透明区的能量范围几乎是xx 光的2 倍, 应用 WSe2 晶体的这一特性可以制备不同要求的偏振片.     

Na2SO3溶液的拉曼光谱研究和保存

使用抗坏血酸(VC)代替甲醛作为保护剂,通过拉曼光谱仪测试SO32-、SO42-的拉曼峰的转变过程来观察Na2 SO3溶液变质情况,测试简单,快速.实验表明,Na2 SO3溶于煮沸冷却后的蒸馏水,以VC作为保护剂,当浓度为0.5 mol/L时,可以持续暴露在空气中保存12h以内不变质;当通入N2或煮沸冷却后的蒸馏水或添...     

Synchrotron X-ray diffraction study of haüyne at high pressure

The compression behavior of a natural haüyne has been investigated to about 8.1 GPa at 300 K using in situ angle-dispersive X-ray diffraction and a diamond anvil cell at High Pressure Experiment Station, Beijing Synchrotron Radiation Facility (BSRF). Over this pressure range, no phase change or disproportionation has been observed. The isothermal equation of state was determined for the first time. The values of V₀, K₀, and K′₀ refined with a third-order Birch-Murnaghan equation of state are V₀=751.6±0.4 Å³, K₀=49±1 GPa, and K′₀=3.3±0.3, respectively.     

比较分析治疗虚证中药中微量元素溶出率

采用原子吸收光谱法,测定治疗虚证中药中微量元素溶出率,为临床上安全、有效地利用中药微量元素及进一步了解、提高服用中药的质量提供科学参考数据。实验测得十味中药中6种微量元素平均溶出率为17.78%,Zn、Cu、Mn、Fe、Co、Cr的平均溶出率分别为15.10%,14.79%,20.95%,22.82%,16.71%,16.31%。结果表明,除Fe、Mn平均溶出率高于6种微量元素平均溶出率外,其他4种微量元素Zn、Cu、Co、Cr的平均溶出率均低于该值,且彼此之间无显著性差异。     

碘回收工艺中硫酸盐含量的快速测定

介绍了一种用UV-1600型紫外可见分光光度计快速测定碘回收工艺中硫酸盐含量的方法.以氯化镁、乙酸钠、硝酸钾和乙醇为缓冲溶液,在440nm处测量吸光度,硫酸盐浓度在0-50μg/mL符合比耳定律,可决系数为0.9996.将所得碘吸收液中硫酸盐含量与重量法所得结果对比,确定分光光度法是实验室快速测定碘回收工艺中硫酸盐含量...