渐近欧氏流形上带有阻尼和位势项的波动方程的生命跨度估*

本文研究了渐近欧氏流形上带有阻尼和位势的半线性波动方程的有限时间破裂以及解的生命跨度上界估计,其半线性项是形如c₁ |u_t|^p + c₂ |u|^p的混合项. 该问题与Strauss猜测和Glassey猜测紧密相关.     

MC98-A型多功能极谱仪研制

以８０９８单片机作智能部件的小型多功能极谱仪，采用ＳＴＤ标准总线结构，汉字菜单式提示，人－机对话方式操作。以阳极溶出和电位溶出分析为主，用三种定量分析方法直接显示，打印出测试曲线和分析结果。     

库仑双点滴定法研究——Ⅰ.离子选择电极电位法

本文提出以离子选择性电极为指示电极的库仑双点滴定的实验方法,推导出定量公式和相对误差公式,探讨了影响准确度的主要因素。     

分子动力学模拟3(5)-(9-蒽基)吡唑分子在自组装膜上的选择性沉积

采用平衡分子动力学和拉伸分子动力学模拟方法研究了模板诱导有机发光小分子3(5)-(9-蒽基)吡唑(ANP)在自组装膜上的选择性沉积,并利用伞形取样方法和加权柱状图分析法计算了沉积过程的均力势.模拟中以二氧化硅为底板分别构筑2种不同密度的烷烃链自组装膜模板,即低密度的液体扩展相和高密度的液体压缩相.平衡分子动力学结果显示,ANP分子容易沉积至低密度的液体扩展相中,难以沉积至高密度的液体压缩相中.拉伸分子动力学结果表明,当ANP分子沉积至液体压缩相表面时,在进入烷烃膜时遇到较大阻力,因而不易进入到烷烃链单层膜中;而ANP分子在进入液体扩展相的过程中受到的阻力较小.通过比较这2种不同密度自组装膜与ANP分子之间的结合自由能,发现ANP分子进入液体压缩相的能垒较高,而ANP分子与液体扩展相结合更加稳定,导致有机发光小分子在不同密度的模板上具有选择吸附性.所得模拟结果与实验现象一致,在分子水平上为实验提供了更加丰富的微观信息.     

水辅助下的OH自由基与CH_3OOH气相反应机理的理论研究

利用量子化学计算方法对单个水分子不存在与存在的情况下OH自由基与CH3OOH的气相氢抽取反应进行了理论研究.在BHand HLYP/6-311++G(2df,2pd)理论水平下优化了所有驻点的几何构型,在此基础上利用CCSD(T)/cc-p VTZ方法对所有驻点的单点能重新进行了计算.计算结果表明,OH自由基与CH3OOH反应的主要通道是OH自由基抽取CH3OOH中的-OH基团上的H原子.在单个水分子存在的情况下,反应的主要通道没有改变,但是水化过渡态的能量显著地降低,显然单个水分子对OH+CH3OOH反应具有催化效应.     

PdnAu(n=1-5)团簇的结构与性质研究

在相对论有效原子实势近似下,用密度泛函方法(B3LYP/LANL2DZ)计算了掺杂二元合金PdnAu(n=1-5) 团簇可能的几何构型和对应的电子态,讨论了团簇的稳定性,得到一系列稳定异构体的结构参数、电子态、能量和谐振频率,部分稳定构型具有较高的自旋多重性.结果表明,Pd-Au相互作用较强、改变了纯钯团簇的稳定构型, 合金团簇的稳定性随体积增大而降低.     

The protectivity of aluminum and its alloys with transition metals

The mechanism of the protectivity of aluminum and supersaturated aluminum alloys containing W, Mo, Ta and Cu has been investigated in chloride environments. The potential of zero charge (PZC) of the passive film was evaluated by a method based on impedance spectroscopy. The chloride ion adsorption on the passive film was measured by means of an in situ radiotracer technique. Constituents of the passive film as a function of depth were investigated by means of ex situ spectroscopic techniques including XPS, ISS and SIMS. The PZCs of the passive films of Al and Al alloys were calculated from the flatband potentials. A linear correlation between pitting potential and the PZC was found. Adsorption of the chloride ion on the Al-Ta surface starts at more anodic potentials than those of pure Al, and this shift is in agreement with the anodic shift of the PZC. A constant surface concentration of chloride ion was observed during the induction time for breakdown. A significant de crease of OH⁻ concentration in the passive film of Al and its alloys has been found after the passive film has undergone breakdown. The mole fraction of the alloying elements in the surface region of the passive film is ca. 1–8%. The adsorption of the chloride ion on the surface of the passive film is influenced by the anodic PZC shift, which varies with the alloying element. However, retardation of the chloride penetration into the passive film by blocking of the entry site by oxide ions of the alloying element controls the rate of breakdown. Received: 18 November 1996 / Accepted: 17 February 1996     

乙烯基自由基(C2H·3)与羟基自由基(OH·)反应势能面的理论研究

在QCISD（T）/6-311G（2df,p)//B3LYP/6-311G（d,p)水平上对自由基反应C2H3^. OH^.进行了计算，结果表明，经过缔合、多步H转移、CH3转移和离解等复杂过程，最终要得到8种产物（P1-P8），茯中产物P2（H2CCO H2）和P6（CH3CO^. H^.）是主要产物。本文得到的CH2CHOH（1或1‘），CH3CHO（2）和CH3COH（3）之间的过渡态TS1/2，TS1‘/3和TS2/3的能量顺序与Wesdemiotis等的实验推测相反，而与Smith等的计算结果一致。     

Saddle points of index 2 on potential energy surfaces and their role in theoretical reactivity investigations

After a general characterization of second order saddle points two boundary cases are derived and illustrated by examples. The utilization of the classification is pointed out. One type, the virtual saddle point of index 2 (V-SP 2), may be understood as geometrical superposition of two saddles of index 1 (transition structures) which belong to relatively independent processes within the chemical system.     

Theoretical Studies on the Mechanism of Mannich Reaction Involving Iminium Salt as Potential Mannich Reagent(1)——Use Acetaldehyde as Pseudo-acid Component

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