尿碘标准物质测量方法的评价

将快速尿碘试剂盒法和标准方法对尿碘标准物质的测定结果与其标准值比较,观测结果有无差异,再用正态分布小样本容量的简化检验法和方差检验法判定快速尿碘试剂盒法与标准方法对尿碘标准物质测定结果的差异,以评价不同方法对尿碘标准物质测定结果的一致性。     

关于化学课堂提问的思考

新一轮基础教育课程改革给课堂提问赋予了新的内涵,在新的课程理念下,教师应该重新审视课堂提问,合理设计课堂提问,通过提问促进课堂上的交流,发展学生的思维能力和解决问题的能力,使提问成为师生共同发现、理解和探究知识的重要途径.     

烷基聚葡糖苷微乳液中脂肪酶催化的酯合成反应动力学

在烷基聚葡糖苷C10G1．54／正丁醇／环己烷／磷酸盐缓冲液体系形成的油包水微乳液中,研究了在较高底物浓度下,脂肪酶催化正己酸和正丁醇的酯合成反应动力学及其影响因素。结果表明,在正己酸的初始浓度CHA^0较小时,反应初速率V0随正己酸浓度增大而增大,但随正丁醇表观浓度增大而减小;在CHA^0较大时,反应初速率V0随正丁醇表观浓度增大而增大,但随正己酸浓度增大而减小．在正己酸和正丁醇摩尔浓度之比为3．0左右反应速率最大．这些实验结果与传统的米氏反应不符,为此,从界面膜的构成,尤其是两种底物在界面膜上的分布情况人手进行了探讨．考察了C10G1.54浓度、正丁醇浓度和两者总浓度等对反应初速率V0的影响．     

1,8-二巯基芘分子电学特性的理论研究

Based on the first principle,electrical properties of a molecular junction consisting of pyrene-1,8-dithiol molecule and gold surface have been investigated. The cluster of three gold atoms is used to simulate the gold surface. Density functional theory is employed to obtain the electronic structures of the molecule and the extended molecule. Then the frontier orbital theory and the perturbation theory are used to determine the interaction energy between the molecule and the gold surface quantitatively. The elastic Green function method is applied to study the current-voltage properties of the molecular junction. Numerical results show that the sulfur atoms can be chemically absorbed on the gold surface and the bonding between the molecule and gold is mainly covalent-typed. The fermienergy of the extended molecular system lies between the HOMO and the LUMO and closer to the HOMO of the system. When the external applied bias is lower than 1 V,there is a current gap for the molecular junction. With the increasing of the bias,the conductance of the junction exhibits plateaus. These electrical properties are closely related with the electronic structures of the molecular junction. The extended molecular orbits have great contribution to the charge transport. Localized molecular orbits give little contribution to the current while charge transport is taken place by tunneling.     

卤代对苝醌类光敏剂光敏活性影响的量子化学研究

Taking hypomycin B（HMB）as the model compound,HF / 6-31G and TD-B3LYP / 6-31G methods have been employed to explore the effect of chlorine,bromine and iodine substitutions on molecular properties and photosensitization of perylenequinonoid photosensitizer（PQP）. It was found firstly that,the halogen substitutions lowered the EHOMO and ELUMO,and the ΔE. From chlorine,bromine to iodine substitutes,the EHOMO and ELUMO increased,while the corresponding ΔE decreased. Secondly,the halogen substitutions increased the molecular triplet-generating quantum yields and lowered the molecular lowest lying triplet energies,which resulted in the substitutes’similar 1O2 yields with their parent compounds. After halogen substitutions,the molecular adiabatic electron affinities increased,which made the substitutes possess lower O2· - -generating abilities than their parent compounds. Finally,the halogen substitutions lowered the intramolecular hydrogen bond energies,while enhancing the intramolecular proton transfer（IPT）barriers of cis isomers and lowering those of trans isomers on the ground state.     

Monte Carlo方法计算背散射电子在固体中的空间分布

应用Monte Carlo方法,对不同能量低能电子作用下背散射电子在固体中的空间分布作了计算,电子的弹性散射用Mott截面描述、非弹性散射按文献[3]的方法由Streitwolf、Quinn及Gryrinski的公式计算,大量计算得出一些规律,为低能电子显微学研究提供一定依据。     

微分吸附计时电位法测定溴莫普林

提出一种测定新药溴莫普林（ＢＤＰ）的微分吸附计时电位法。在Ｍｉｃｈａｃｌｉｓ（ＭＣＬ）缓冲液中溴莫普林于一１．３３Ｖ左右产生一灵敏的微分吸附计时电位溶出峰,利用该峰测定ＢＤＰ的线性范围为２．０×１０＾－８－３．０×１０＾－７ｍｏｌ／Ｌ,吸附富集３ｍｉｎ检测下限为５．０×１０＾－９ｍｏｌ／Ｌ。探讨了影响灵敏度的主要因素,用循环伏安法,脉冲极谱等多种是化学方法研究了该体系的电化学行为和电极机理,认为所     

白果中脂肪酸的GC-MS分析

将萃取所得白果油进行皂化、甲酯化后 ,进行GC-MS定性及相对含量分析 ,取得了满意的结果。实验检出30种脂肪酸 ,其中亚油酸和油酸占71.8%,不饱和脂肪酸占87.86%。     

香草醛—N—酰腙类化合物的合成与表征

Ｓｃｈｉｆｆ碱类化合物和酰腙类化合物大多具有除草,杀菌等生物活性,已有一些报道［１,２］,对该类化合物的深入研究是当今农药界热点之一,表明此类化合物具有广阔的开发前景。据文献报道［１］,香草醛与芳胺反应生成的Ｓｃｈｉｆｆ碱类化合物具有优异的促进植物生根性。为寻求新的具有生物活性的物质,我们采用香草醛与酰肼反应,合成了３种未见报道的酰腙类化合物。其结构经ＩＲ,１ＨＮＭＲ和元素分析证实。合成反应如下：３—ＣＨ３Ｏ—４—ＨＯＣ６Ｈ３ＣＨＯ＋Ｈ２ＮＮＨＣＯ—Ｒ３—ＣＨ３Ｏ—４—ＨＯＣ６Ｈ３ＣＨＮＮＨＣＯ…     

电镜用双层支持膜的制备及应用

本文综合了Formvar膜强度大和火棉胶膜分散性好的优点,制备出了Formvar-火棉胶双层支持膜。Formvar膜在下层增大了膜的强度,火棉胶膜在上层改善了膜的分散性。根据电镜对支持膜的特殊要求,摸索出了制备双层支持膜的原料溶液的浓度范围及浓度配比范围,并且通过红外光谱(IR)证实了双层支持膜结构的存在。通过实际应用,发现双层支持膜具有高分辨率、强电子束照射下膜保持稳定不破损等优点,双层支持膜比以前传统使用的单层支持膜在许多方面都取得了较大的改善,尤其适用于纳米材料的电镜观察,因此,值得进一步推广应用。