新型固体酸SO_4~(2-)MoO_3-TiO_2催化合成苹果酯

自制了一种新固体酸催化剂SO2 -4MoO3 -TiO2 ,FT -IR谱图表明 ,催化剂表面具有强酸中心 ,该催化剂对苹果酯合成的活性高 ,并得到该反应的优化条件如下 :乙酰乙酸乙酯 0 .3mol,乙二醇 0 .6mol,环己烷 30ml,催化剂 3g ,反应温度 110℃ ,反应时间 1.5h ,在此条件下 ,苹果酯产率达 90 % ,且催化剂易回收 ,具有较好的重复使用性能     

从CET-4新题型看大学英语词汇教学

本文结合最新的四级题型,分析了大学英语新四级考试中词汇的测试特点,对大学英语词汇教学提出了一些有效的教学方法.     

Ab initio study of the effects of Ag/Mn doping on the electronic structure of LiFePO_4

Based on density functional theory (DFT) of the first-principle for the cathode materials of lithium ion battery, the electronic structures of Li(Fe1-xMex)PO4 (Me = Ag/Mn, x = 0―0.40) are calculated by plane wave pseudo-potential method using Cambridge serial total energy package (CASTEP) program. The calculated results show that the Fermi level of mixed atoms Fe1-xAgx moves into its conduction bands (CBs) due to the Ag doping. The Li(Fe1-xAgx)PO4 system displays the periodic direct semiconductor characteristic with the increase of Ag-doped concentration. However, for Fe1-xMnx mixed atoms, the Fermi level is pined at the bottom of conduction bands (CBs), which is ascribed to the interaction be-tween Mn(3d) electrons and Fe(4s) electrons. The intensity of the partial density of states (PDOS) near the bottom of CBs becomes stronger with the increase of Mn-doped concentration. The Fermi energy of the Li(Fe1-xMnx)PO4 reaches maximum at x = 0.25, which is consistent with the experimental value of x = 0.20. The whole conduction property of Mn-doped LiFePO4 is superior to that of Ag-doped LiFePO4 cathode material, but the structural stability is reverse.     

Theoretical study on the lithium bond interaction of furan homologues C_4H_4Y (Y=O, S) with LiCH_3 via DFT and MP2

The optimizations geometries and interaction energy corrected by BSSE of the complexes between C4H4Y (Y=O, S) and CH3Li have been calculated at the B3LYP/6-311 G** and MP2/6-311 G** levels. Three complexes were obtained. Abnormally, the calculations showed that all the C10—Li14 bond lengths increased obviously but the blue-shift of C10—Li14 stretching frequency occurred after formed complexes. The calculated binding energy with basis set super-position error (BSSE) and zero-point vibrational energy corrections of complexes I―III is ?45.757, ?35.700 and ?39.107 kJ·mol?1, respectively. The analyses on the combining interaction with the atom-in-molecules theory (AIM) also showed that a relatively strong lithium bond interaction presented in furan homologues C4H4Y---LiCH3 systems. Natural bond orbital theory (NBO) analysis has been performed, and the results revealed that the com- plex I is formed with n-σ type lithium bond interaction between C4H4O and LiCH3, complex II is formed with π-s type lithium bond interaction between C4H4O and LiCH3, and complex III is formed with π-s and n-s type lithium bond interactions between C4H4S and LiCH3, respectively.     

射频溅射金属前驱体硫化法制备的Cu2ZnSnS4薄膜

采用射频溅射技术沉积Cu／Sn／Zn金属前驱体叠层结合硫化技术在玻璃衬底上成功制备了Cu2ZnSnS4薄膜。X-射线衍射分析表明，通过优化制备条件可以获得单一黝锡矿结构且具有（221）择优取向的Cu2ZnSnS4薄膜。霍尔效应和紫外可见透过谱测量表明，样品的薄膜电阻、吸收系数和光学带隙分别达到0．073Ω·cm，10^4cm^-1和1．53eV，具有适合作为薄膜太阳电池吸收层应用的可能性。     

基于Nexperia数字多媒体平台的设计与实现

设计并实现了以Nexperia PNX1300 Series媒体处理器为核心，集视频、音频、通信、图象和控制为一体的数字多媒体平台，它具有高性能的实时数字信号处理能力，是数字多媒体编解码标准的算法研究与实现的理想平台，实验证明，数字多媒体平台是一个性能卓越、功能强大的实时信号采集与处理系统，完全满足数字多媒体实时处理的需要，它将MPEG-4的视频压缩技术与流媒体技术结合，具有广泛的应用前景。     

NH_4HCO_3作沉淀剂制备超细Ce-Zr-O粉末的研究

为寻求简便、合理的合成超细粉体的方法,利用NH4HCO3 作沉淀剂,通过考察料液配比、加料速度、升温速度等实验因素,得到了简单的合成超细 Ce Zr O粉末的工艺,并利用比表面积测定仪、激光粒度仪、XRD、Raman等仪器对相关产物进行了表征.结果表明:利用简单工艺合成的超细 Ce Zr O粉末具有中位粒径为0.30μm、比表面积为21.2 m2/g、悬浮性大于30 min、松装密度小于 1 g/cm3等性能,产物具有 CaF2 型的空间结构.     

Pharmacodynamic profile of CQP 201-403, a novel 8α-amino-ergoline

Summary The profile of action in animals of CQP 201-403, a novel 8-amino-ergoline, is in most aspects that of a very potent dopaminomimetic, both as a prolactin secretion inhibitor, and at the levels of the CNS and the cardiovascular system. Qualitatively CQP 201-403 differs slightly from bromocriptine and apomorphine in its effects on the CNS (no influence on serotonin metabolism in the rat cortex; induction of masculine mounting behavior in rats) and the cardiovascular system of the dog (reflex tachycardia in response to a blood-pressure fall). In man the new compound proved to be highly active in lowering prolactin serum levels and to be more potent than bromocriptine (Parlodel^®).In memory of Dr Annemarie Closse, who died 14 June 1987.