Cu（Ⅱ）—A沸石的表征

用ESR表征了几种Cu(Ⅱ)-A沸石中Cu~(2+)离子物种,发现在铜含量较高(5.20wt%)的样品中,偶极-偶合的Cu~(2+)离子对占压倒优势,而孤立的Cu~(2+)离子则很少.样品还原后的ESR结果表明,偶极-偶合的Cu~(2+)离子对至少存在着两种不同类型的物种.结合ESR、XPS和XRD方法,研究了Cu(Ⅱ)-A沸石中共存阳离了Mn~(2+)的效应,并讨论了Cu~(2+)和Mn~(2+)两种离子间的氧化还原反应.     

Re_3W的点接触安德烈夫反射谱研究

本文通过对不同晶体结构Re_3W样品的点接触测量和对比研究,证实具有中心对称结构和非中心对称结构的Re_3W都是弱耦合Bardeen-Cooper-Schrieffer超导体,同时发现在两个相表面都可以形成很理想的点接触结,即电子通过界面时受到的非弹性散射很弱.将Re_3W样品置于大气环境近六个月后重新进行测量,仍然能够得到类似的结果,表明Re_3W具有很好的稳定性. Re_3W的这种优良特性,不仅可通过点接触实验得到的参数推算出Re_3W两个相的费米速度,而且提供了一种简单的方法,可以在点接触实验中利用Re_3W来印证针尖材料的费米速度和测量其自旋极化率等.作为尝试,本文用Re_3W/Ni点接触结测量了铁磁性金属Ni的自旋极化率,得到了与前人报道一致的结果.     

QUANTITATIVE EXPLANATION ON STRUCTURE-CARCINOGENIC ACTIVITY RELATIONSHIP OF AROMATIC AMINES BY DI-REGION THEORY

Di-region theory, the theory for the mechanism of carcinogenesis, has been extendedsuccessfully on the quantitative Structure-carcinogenic activity relationship (QSCAR) of 63aromatic amines. A quantitative equation for the QSCAR of aromatic amines has been estab-lished by the mechanism conception of the specialized di- functional alkylation between thenitrenium ion of the amino group and the epoxide of the aromatic ring. The agreementbetween calculation and experiment comes up to 98%. Thus, it can now express the puzzlingvariation of the carcinogenicity of aromatic amines, as a comprehensible structure-chemicalreactivity relationship.     

Influence of Mg Composition on Optical Properties of Exciton Confinement in Strained Wurtzite ZnO/Mg_x Zn_(1-x) O Cylindrical Quantum Dots

Based on the effective-mass approximation and variational approach, excitonic optical properties are investigated theoretically in strained wurtzite (WZ) ZnO/Mg x Zn 1-x O cylindrical quantum dots (QDs) for four different Mg compositions: x = 0.08, 0.14, 0.25, and 0.33, with considering a three-dimensional carrier confinement in QDs and a strong built-in electric field effect due to the piezoelectricity and spontaneous polarization. The ground-state exciton binding energy, the interband emission wavelength, and the radiative lifetime as functions of the QD structural parameters (height and radius) are calculated in detail. The computations are performed in the case of finite band offset. Numerical results elucidate that Mg composition has a significant influence on the exciton states and optical properties of ZnO/Mg x Zn 1 x O QDs. The ground-state exciton binding energy increases with increasing Mg composition and the increment tendency is more prominent for small height QDs. As Mg composition increases, the interband emission wavelength has a blue-shift if the dot height L 3.5 nm, but the interband emission wavelength has a red-shift when L 3.5 nm. Furthermore, the radiative lifetime increases rapidly with increasing Mg composition if the dot height L 3 nm and the increment tendency is more prominent for large height QDs. The physical reason has been analyzed in depth.     

Ionized Acceptor Bound Exciton States in Wurtzite GaN/Al_xGa(1-x)N Cylindrical Quantum Dot

Based on the framework of the effective-mass approximation,the ionized acceptor bound exciton(A-,X) binding energy and the emission wavelength are investigated for a cylindrical wurtzite(WZ) GaN/Al x Ga1-x N quantum dot(QD) with finite potential barriers by means of a variational method.Numerical results show that the binding energy and the emission wavelength highly depend on the QD size,the position of the ionized acceptor and the Al composition x of the barrier material Al x Ga1-x N.The binding energy and the emission wavelength are larger when the acceptor is located in the vicinity of the left interface of the QD.In particular,the binding energy of(A-,X) complex is insensitive to the dot height when the acceptor is located at the left boundary of the QD.The ionized acceptor bound exciton binding energy and the emission wavelength are both increased if Al composition x is increased.     

基于苯并噻二唑结构的近红外二区有机小分子在生物成像和治疗中的研究进展EI北大核心CSCD

基于光子反射、散射和自发荧光的减弱,近红外二区窗口能够实现高分辨率和信噪比的生物荧光成像,在各种生物医学应用中发挥着重要作用。构建供体-受体-供体结构是设计近红外二区有机小分子的有效方法,基于苯并噻二唑结构的近红外二区有机小分子不仅能够实现光学成像,还能利用光激活的激发态能量转换实现光学治疗。本文总结了基于苯并双噻二唑(Benzobisthiadiazole,BBT)和[1,2,5]噻二唑[3,4-g]喹喔啉([1,2,5]thiadiazolo[3,4-g]quinoxaline,TQ)结构的近红外二区有机小分子在生物成像和成像引导的治疗中的研究进展,并对未来近红外二区有机小分子的设计和应用进行了展望。     

“乙炔羰基化合成丙烯酸”通过鉴定

本项研究以乙炔、CO和水为原料,在8MPa压力及220～230℃温度下催化合成丙烯酸.产品纯度高,工艺流程合理,适合在天然气和煤炭资源丰富的地区推广应用。1990年7月通过了由四川省化工厅和省科委主持的小试成果鉴定。经四川省计经委和省化工厅91     

累托石合成A型分子筛及物化性能研究

目前,对 A 型分子筛的需求日益增长,而利用天然资源制备分子筛既可节省化工原料,又能合理利用资源。故探索以天然资源为原料研制分子筛是有一定意义的。国内外均有使用高岭土、膨润土合成 A 型分子筛的报道。本文     

粘接多胞管三点弯曲实验与数值研究

基于实验和数值模拟方法,论文对一种易制备粘接多胞薄壁结构的弯曲性能进行了研究,分析了粘接多胞管在横向三点弯曲载荷作用下的变形和能量吸收性能.三点弯曲准静态实验表明由于粘接的作用,通常情况下粘接多胞管的能量吸收性能高于其基本构成单胞管能量吸收的总和,某些情况下粘接可以最高带来近70%的性能提升.基于有限元软件LS-DYNA,对三点弯曲实验进行了数值模拟仿真,计算得到的结构变形模式和力-位移曲线与实验结果吻合良好.此外,采用数值方法,对三种不同接触条件下的结构响应进行了对比分析,结果表明若未出现明显的粘接脱开,则多胞管的吸能特性与完整的多胞结构相当,否则其能量吸收性能会被严重削弱.     

芳胺结构致癌活性关系的双区理论定量阐释

本文将双区理论定量地推广到63种芳胺的定量结构致癌活性关系上,借氨基亚氮阳离子与环上环氧化物的双官能烷化作用的观点,建立了芳胺结构与致癌性能间的定量关系式,计算与实验的一致达98％。从而将芳胺类难以捉摸的致癌性能变化,表达为可以理解的结构化学活性关系。