A Novel Method for the Synthesis of Mesoporous Molecular Sieve MCM-41

Using glycerol, glycol and water as solvent, cetyltrimethylammonium bromide (CTAB) as template, tetraethyl orthosilicate (TEOS) as silica source, ethylenediamine (EDA) as base source, mesoporous molecular sieve MCM-41 has been synthesized at room temperature, characterized by X-ray power diffraction and N2 adsorption. Compared with the samples synthesized by glycol and water, the samples synthesized by glycerol have larger pore diameter and high surface areas. Thus glycerol is an efficient solvent for preparing larger pore mesoporous MCM-41.     

DIFFERENTIAL, LETHAL AND MUTAGENIC ACTION OF 254 nm AND 320–400 nm RADIATION ON SEMI-DRIED BACTERIA

Abstract— The effect of culture conditions on the lethal and mutagenic action of 254 nm (u.v.) and 320–400 nm (b.l.) light has been examined. Ten strains of Escherichin coli were used in these investigations. It was found that semi-dehydration in aerosols greatly enhanced the lethal and mutagenic actions of both U.V. and b.l., Mutations induced by U.V. were found to be of a random kind, while those produced by b.l. were specific and of a particular biochemical type depending on the strain of cell and its stage of development. The presence of oxygen during irradiation enhanced b.l. effects but had no effect on U.V. damage while anaerobic growth endowed the cells with added resistance to b.l. and u.v., Stationary phase cells of E. coli B/r were found to be mutated by b.l. specifically at a thymine locus and to be more sensitive than E. coli B to the inhibition by b.l. of respiration. Some mutations induced by b.l. in E. coli B/r were found to hinder the cells ability to carry out the photoreversal of U.V. damage. It is suggested that b.1. affects a specific piece of DNA which is in contact with the cytochrome chain of the cytoplasmic membrane and that this contact point between the cytochrome chain and DNA alters sequentially as the cell proceeds through its life cycle.     

东北草甸棕壤的零电荷点和界面酸-碱反应特征平衡常数

分别采用电势滴定(Potentiometric titration)法, 质量滴定(Mass titration)法和惰性电解质滴定(Inert electrolyte titration)法测定了荷结构负电荷的东北草甸棕壤的零净电荷点(PZNC), 研究表明荷结构负电荷的土壤依然存在与电解质浓度无关的零净电荷点, 三种方法的实验结果分别为2.9, 5.0和3.3. 相比较而言, 电势滴定法和惰性电解质滴定法的结果相近, 而质量滴定法的结果偏高. 对文献中推算表面质子活性位密度(N_s)的方法进行了改进, 得到东北草甸棕壤样品的N_s为2.5 mmol•g^－1. 根据实验测定的pH_PZNC, N_s和结构电荷密度(σ_st)值直接计算得出东北草甸棕壤样品的界面反应特征平衡常数即1-pK模型中的pK, 2-pK模型中pK_a1^int和pK_a2^int, 分别为3.37, 2.42和4.32, 与文献报道的沉积物和蒙脱土的值相吻合.     

向日葵仁中绿原酸和咖啡酸的反相高效液相色谱法测定

建立了同时测定向日葵仁中绿原酸和咖啡酸的反相高效液相色谱法 ;采用美国Alltech公司的ALLTIMAC18 柱(250mm×4.6mmID,5μm) ,流动相为乙腈 -2 %(φ)乙酸溶液 (体积比15∶85) ,流速为1.0mL/min ,紫外检测波长327nm ;向日葵仁中绿原酸(chlorogenicacid)和咖啡酸(caffeicacid)在18min内得到很好的分离 ,该法简便、快速、结果准确、重复性好。     

对N=184附近核的壳效应的理论研究

在形变的相对论平均场模型下采用TMA,NLZ2两套参数对Z=96—102,N=162—190区域偶偶核基态性质进行了系统的计算,对得出的理论结合能、α衰变能、四极形变参数进行了分析和讨论.这些结果同已有的SkyrmeHartreeFock计算的结果做了对比,并分析了在N=184附近的壳效应,可供以后理论或实验研究参考.     

1550nm工作波长新颖结构细径偏振保持光纤的制备及性能研究

对工作波长在1550nm，新型结构细径偏振保持光纤的制备与性能进行研究，并制备出拍长达到2．1mm、消光比达到28dB（1km）、工作波长在1550nm、低衰减且高强度的细径偏振保持光纤．     

弱磁场中质子的自由进动和一个野外测磁场的实验

本文报导了我们在弱场中进行的核矩预极化和核矩自由进动的实验和分析。主要研究了极化磁场衰减过程中核矩的运动、讯号的绝对强度,并观察到探头转动对讯号频率的影响,指出了这是测核磁矩正负号的最直接的方法。此外,弱磁场中质子自由进动现象在高空磁场测量、地质探矿、石油开采等方面都有重要的实际应用,本文的结果对解决这些应用中的具体问题是有帮助的。为了检验全套仪器在野外工作时的性能,以及观察周围大体积的磁性物质对讯号频率的影响,我们在野外进行了一系列的测磁实验,获得了肯定的结果。测磁的相对精密度达到1×10^-5。     

Shell Effect of Superheavy Nuclei in Self-consistent Mean-Field Models

We analyze in detail the numerical results of superheavy nuclei in deformed relativistic mean-field model and deformed Skyrme-Hartree-Fock model. The common points and differences of both models are systematically compared and discussed. Their consequences on the stability of superheavy nuclei are explored and explained. The theoreticalresults are compared with new data of superheavy nuclei from GSI and from Dubna and reasonable agreement is reached.Nuclear shell effect in superheavy region is analyzed and discussed. The spherical shell effect disappears in some cases due to the appearance of deformation or superdeformation in the ground states of nuclei, where valence nucleons occupysignificantly the intruder levels of nuclei. It is shown for the first time that the significant occupation of vaJence nucleons on the intruder states plays an important role for the ground state properties of superheavy nuclei. Nuclei are stable in the deformed or superdeformed configurations. We further point out that one cannot obtain the octupole deformation of even-even nuclei in the present relativistic mean-field model with the σ,ω and ρ mesons because there is no parityviolating interaction and the conservation of parity of even-even nuclei is a basic assumption of the present relativistic mean-field model.     

弱视儿童血铅测定情况分析

探讨了血铅水平与儿童弱视的关系。分别检测了弱视儿童42例及正常对照儿童30例的血铅水平。结果表明,弱视组铅中毒人数明显高于正常组,差异有显著性。提示铅中毒儿童具有视觉发育障碍的高风险性,应重视患和的眼科随访工作,防治弱视。     

萘在硝酸/醋酸酐体系下选择性硝化

研究了萘在硝酸/醋酸酐体系下选择性硝化,以发烟硝酸(95％)为硝化试剂,乙酸酐作为反应溶剂.最佳反应条件是:萘0.51g(4mmol)、乙酸酐(5.00mL)、催化剂CdZSM-50.10g、发烟硝酸o.27mL(6mmol),冰浴下搅拌反应,～硝化物回收率73.84％,1-硝基萘与2-硝基萘异构体的比值为3.93.目标产物用红外光谱和核磁共振表征.