Ni(111)表面一氧化碳和氢共吸附的密度泛函理论研究

本文用密度泛函理论(DFT)的总能计算研究了一氧化碳和氢原子在Ni(111)表面上p(2×2)共吸附系统的原子结构和电子态，结果表明CO和H原子分别被吸附于两个对角p(1×1)元胞的hcp和fcc位置.以氢分子和CO分子作为能量参考点，总吸附能为2.81 eV，相应的共吸附表面功函数φ为6.28 eV.计算得到的C—O，C—Ni和H—Ni的键长分别是1.19?, 1.96?和 1.71?，并且CO分子以C原子处于hcp的谷位与金属衬底原子结合.衬底Ni(111)的最外两层的晶面间距在吸附后的相对变化分别是 关键词： Fisher-Tropsch反应 催化作用 Ni(111) p(2×2)/(CO+H) 共吸附     

光电对抗在现代防空作战中的应用与展望

在综述光电对抗内涵的基础上，论述光电对抗在现代战争作战平台中的具体应用，并着重从电子战的角度论述了光电对抗在现代防空作战中的最新应用。最后指出光电对抗技术在未来电子战中的作用和发展方向。     

退火对电子束热蒸发193nm Al2O3/MgF2反射膜性能的影响

设计并镀制了193nm Al2O3/MgF2反射膜,对它们在空气中分别进行了250-400℃的高温退火,测量了样品的透射率光谱曲线和绝对反射率光谱曲线.发现样品在高反射区的总的光学损耗随退火温度的升高而下降,而后趋于饱和.采用总积分散射的方法对样品在不同退火温度下的散射损耗进行了分析,发现随着退火温度的升高散射损耗有所增加.因此,总的光学损耗的下降是由于吸收损耗而不是散射损耗起主导作用.对Al2O3材料的单层膜进行了同等条件的退火处理,由它们光学性能的变化推导出它们的折射率和消光系数的变化,从而解释了相应的多层膜光学性能变化的原因.反射膜的反射率在优化联系、镀膜工艺与退火工艺的基础上达98%以上.     

动态光散射实验

动态光散射技术是测量纳米及亚微米颗粒粒径的有效方法．本文介绍了动态光散射实验的原理、实验装置及方法，并测量了粒径为85nm的聚苯乙烯水溶液的粒径，分析了实验产生误差的原因．     

THE LARGE TIME BEHAVIOR OF SPECTRAL APPROXIMATION FOR A CLASS OF PSEUDOPARABOLIC VISCOUS DIFFUSION EQUATION

The asymptotic behavior of the solutions to a class of pseudoparabolic viscous diffusion equation with periodic initial condition is studied by using the spectral method. The semidiscrete Fourier approximate solution of the problem is constructed and the error estiation between spectral approximate solution and exact solution on large time is also obtained. The existence of the approximate attractor AN and the upper semicontinuity d(AN,A)→0 are proved.     

ZrxTixAl1-2xO2的制备及其在三效催化剂上的应用

Zr_0.5Ti_0.5O₂(ZT) and Zr_0.25Ti_0.25Al_0.5O₂(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption， XRD and NH₃-TPD. The activity of Pt/Zr_0.5Ti_0.5O₂ and Pt/ Zr_0.5Ti_0.5Al_0.5O₂ catalysts was evaluated using the simulated gases. The results show that ZTA samples exhibit higher specific surface area， larger pore volume and proper surface acidic amount and acidity in comparison with ZT. The results of the catalytic test indicate that Pt/ZT and Pt/ZTA catalysts exhibit excellent low-temperature catalytic activity and lower light-off temperatures of hydrocarbon， carbon monoxide and nitrogen oxides， especially better conversion for nitrogen oxides (NO_x). The addition of Al₂O₃ into ZT enhanced the anti-aging property of Pt/ ZTA catalysts due to the excellent textural， structural， surface acidity and thermal stability.     

一种新的光致变色膜：Na2WO4-PAA-Glycerol体系研究

A method for preparing Na₂WO₄-PAA-Glycerol photochromic films was reported. The film was composed of Na₂WO₄, PAA and Glycerol, which were coated on a glass substrate. The film turned blue in the sun, and bleached to transparent in the darkness. The UV-Visible spectra showed strong absorbance at 300～500 nm, and the ABS changed signifanctly at 500～800 nm. The film showed the best photochromic behavior when n_Na2WO4∶n_PAA is 4%～5%. The mechanism was suggested that after irradiation, poly tunstate produced by Na₂WO₄ and PAA formed the tungsten blues. The tungsten blues were bleached due to oxidation back to poly tunstate by oxygen. The film showed not only an excellent photochromism property with rapid response and good reversibility, but also the simple techniques and good stability.     

含氮亲核试剂在2-甲磺酰基-5-(3,4,5-三甲氧基苯基)-1,3,4-噁二唑环上取代反应的研究

2,5—二取代—l,3,4—噁二唑化合物具有消炎,抗菌,调节植物生长,杀虫门等广泛的生物活性。作者曾研究了取代胺在2—甲磺酰基—5—(2—苯基—4—喹啉基)—1,3,4—噁二唑化合物环2—位上的亲核加成消去反应,制得了一系列新的2—取代基—5—(2—苯基—4—喹啉基)—1,3,4—噁二唑衍生物,并发现它们具有一定的抗菌活性。在此基础上,我们又研究了含氮亲核试剂在 2—甲磺酰基—5—(3,4,5—三甲氧基苯基)—1,3,4,—噁二唑环2—位上的亲核加成消去反应,制得一系列新的2—取代基—5—(3,4,5—三甲氧基苯基)—1,3,4—噁二唑衍生物。作者用3,4,5—三甲氧基苯甲酰肼在KOH催化下与CS_2反应得到2—巯基—5—(3,4,5—三甲氧基苯基)—l,3,4—噁二唑1,1在NaOH溶液中与Me_2S0_4作用得到2—甲硫醚—5—(3,4,5—三甲氧基苯基)—1,3,4—噁二唑2,2在冰醋酸水溶     

N—硅甲基—N—甲酰基苯胺衍生物的合成和生物活性研究

研究了醇钠存在下取代苯胺与氯甲基硅烷在二甲基甲酰胺中的反应，的产和的经元素分析、ＩＲ和Ｈ ＮＭＲ光谱鉴定为Ｎ－硅甲基－Ｎ－甲酰基苯胺衍生物。     

呋喃西林水溶液在光和热作用下的稳定性

The influence of both light and heat on the stability of nitrofurazone aqueous solution was studied. Results show that in either heating experiments or the exposure to light at high temperatures, the degradation rate obeyed zero-order kinetics. The total rate constant ktotal caused by both light and heat can be divided into two parts: ktotal =kdark klight, where kdark and klight are the degradation rate constants caused by heat and light, respectively. The klight can be expressed as klight=Alight*exp(-Ea,light/RT)*E, where E is the illuminance of light, and Alight and Ea,light both are experimental constants. The values of these kinetic parameters were determined based on the experiments in the dark and upon exposure to three different light sources. Results show that the values of Alight and Ea, light varied with the light source. To save time, labor, and drugs, exponential heating experiments were employed and compared with the isothermal experiments. Results indicated that kinetic parameters obtained by exponential heating experiments are comparable to those obtained by isothermal experiments either in the dark or upon exposure to light.