低热固相反应的反应机理研究(Ⅰ)——冷融熔机理和冷溶熔机理的模型

本文提出了低热固相反应的冷融熔机理和冷溶熔机理,其中冷融熔机理主要针对于不含结晶水的反应体系,冷溶熔机理主要针对于含结晶水的反应体系,并对低热固相反应动力学提出冷融熔/冷溶熔、扩散、反应、成核、生长的五步机理。两种机理都避开了分子在固相晶格中的扩散,从而对低热固相反应的扩散问题进行了有效的解释,并给出了低热固相反应的热力学和动力学判据。     

Structure of cis-[Pt(NH_3)(2-picoline)]~(2+) and DNA adduct and its bonding characteristics

Several methods including molecular mechanics, molecular dynamics, ONIOM that combines quantum chemistry with molecular mechanics and standard quantum chemistry are used to study the configuration and electron structures of an adduct of the DMA segment d(ATACATG*G*TACATA)-d(TATGTACCATGTAT) with cis-[Pt(NH3)(2-Picoline)]2+. The investigation shows that the configuration optimized by ONIOM is similar to that determined by NMR. Strong chemical bonds between Pt of the complex and two N7s of neighboring guanines in the DNA duplex and hydrogen bond between the NH3of the complex and O6 of a nearby guanine have a large impact on the configuration of the adduct. Chemical bonds, the aforementioned hydrogen bond, and the interaction between a methyl of the complex and a methyl of the base in close proximity are critical for the complex to specifically recognize DNA.     

甲醇-联吡啶钌(II)体系的电致化学发光研究

研究了碱性溶液中甲醇-联吡啶钌(II)[Ru(bpy)3^2^+]的电致化学发光行为。在玻碳电极上甲醇于+1.28V(vs.Ag/AgCl)处被氧化为甲氧基离子(CH3O.), 该自由基离子发生歧化反应, 生成激发态的甲醛(HCHO), 发出波长为545nm的光。另一方面当体系含有少量的Ru(bpy)3^2^+时会得到较强的发光信号, 发光波长为608nm, 该发光起因于在甲醇的氧化电位下, Ru(bpy)3^2^+被氧化成Ru(bpy)3^3^+, CH3O.与Ru(bpy)3^3^+反应, 生成激发态的Ru(bpy)3^2^+而发光。     

分散固相萃取-液相色谱-串联质谱法测定淡水鱼中柱孢藻毒素、节球藻毒素和微囊藻毒素

建立了同时检测淡水鱼中柱孢藻毒素、节球藻毒素、微囊藻毒素-RR、微囊藻毒素-YR及微囊藻毒素-LR的分散固相萃取-液相色谱-串联质谱方法。样品粉碎后，用乙腈-水-甲酸（89 ∶ 10 ∶ 1，v/v/v）提取目标物，C₁₈分散固相萃取柱净化，Agilent ZORBAX Eclipse XDB C₁₈色谱柱分离，乙腈和水梯度洗脱，在多反应监测（MRM）模式下进行定性分析，基质匹配标准曲线外标法定量。考察了提取溶剂及吸附剂种类对提取效率和净化效果的影响，并优化了液相色谱-串联质谱条件。该法在各自范围内具有良好线性关系，相关系数（R²）≥0.9954；检出限为5~10 μg/kg，定量限为15~40 μg/kg；样品的加标回收率为62.3%~101.2%。该方法前处理方法简单快速，灵敏高效，适用于淡水鱼中柱孢藻毒素、节球藻毒素和微囊藻毒素的有效检测。     

A New Stigmasterol and a New Eremophilenolide from Ligularia dolichobotrys

A new stigmasterol 3β, 7α, 22-trihydoxystigmast-5-ene (1) and a new eremophilenolide 8α-methoxy-6β-angeloyloxyeremophil-7(1 l)-en-8β, 12-olide-14-oic acid (2) were isolated from Ligularia dolichobotrys Diels. Their structures were deduced on the basis of spectral data.     

气相色谱法测定托吡酯中有机溶剂残留量

用填充柱FID-GC外标法在线检测托毗酯中4种有机溶剂残留量，通过线性、准确度、精密度、专属性、最低检测限等试验，证明此方法分离度高、灵敏、准确、简便，能满足检测要求．     

在不同减速因子q_0下体积检验问题的探讨

本文对于零压物优的Friedmann宇宙模型,探讨在不同减速因子q₀下体积检验V/V_m的问题。首先了解在不同q₀值下,相当于红移(z,z_m)的V/V_m值。其次是对前人假定q=0和1下己算过的资料,即对3CR,4C和Parkes三表中三类样品,在一系列不同的q₀值下,计算平均值影响不大;(2)对客体确定z和z_m值后,应用较大的q₀值,将得到较大的V/V_m值,尤其在z_m值大时,更为明显;(3)对于q₀≤1,体积检验法比较可靠,对于q₀>2,尤其q₀>3,当z值增大时,应注意体积检验方法的局限性和失效性。     

纳米复合氧化物AMyAl12-yO19-δ的制备、结构和催化性能

复合氧化物AMyA l12-yO19-δ作为功能无机材料,在许多领域已得到广泛的应用研究。例如可以做超导材料、荧光材料的晶体基质、激光材料等[1]。近年来,作为天然气燃烧反应的催化材料正在进行广泛深入的研究,已经引起了人们越来越多的关注[2-4]。研究表明,复合氧化物AMyA l12-yO19     

纳米晶构筑一维多孔氧化锌的合成与表征

One-dimensional porous zinc oxide was prepared via the calcination of zinc oxalate precursor obtained by solvothermal method. The products were characterized by XRD, SEM, TEM, photoluminescence (PL) spectrum and nitrogen adsorption-desorption. The results show that the obtained zinc oxide sample is porous and constructed by nanoparticles about 30 nm in size. The specific surface area and total pore volume are 126 m²·g^-1 and 0.13 cm³·g^-1, respectively． The PL properties related with defects in ZnO nanoparticles were discussed for porous zinc oxide samples.     

SrFeO3-x对氧的吸附及对甲苯的催化作用

电线、电缆、油漆、印刷、制鞋等产品生产过程中，可产生苯、甲苯、二甲苯等挥发性及毒性的有机体。目前工业上主要用催化燃烧法消除有机废气对环境的污染。所用催化剂主要是贵金属负载在多孔载体上，如Pd／Al2O3，Pt／SiO2等。这类催化剂耗能低，操作简单，氧化温度低，取得了良好效果。但Pd、Pt等贵金属价格昂贵，资源较少，限制了它们的发展。因此，如何得到一种高效价廉的催化剂以取代贵金属催化剂则是推广催化燃烧消除有机废气污染的关键措施之一。