吡嗪分子休克尔本征多项式的快速计算法

应用分子轨道图形理论和休克尔（Ｈüｃｋｅｌ）分子轨道（ＨＭＯ）理论，结合加权分子图和图形分割定理，能简单、快速、准确地求得含２个氮原子的芳杂环（吡嗪分子的休克尔哈密顿）本征多项式（本征函数），所用方法可推广到含１个到２个杂原子的共轭链烯烃和共轭芳烃     

组合方法在共轭体系中的应用

1978年江元生用分子轨道图形理论讨论碳链共轭烃的稳定性,建立了具有明确图形意义的四参数判据: REPE=(Eπ(HMO)-Eπ)/π…………………………………(1) 所得结果,远比Hess和Schaad采用的8键参量表示的REPE以及Aihara提出的稳定性判据好。 (1)式中: Eπ(HMO)是由简单分子轨道理论计算的直键共轭烯烃的π电子总能量。     

高效Zn卟啉类染料分子模型的设计

基于已合成的新型Zn卟啉光敏染料YD2-o-C8,设计一系列以苯、噻吩为共轭桥,以羧酸、氰基丙烯酸为受体的Zn卟啉类光敏染料分子,利用密度泛函理论和含时密度泛函理论方法研究Zn卟啉类光敏染料在四氢呋喃溶液中的稳定构型.研究表明:对桥位和受体的功能化修饰降低了最低未占据分子轨道能级,减小了最高占据分子轨道到最低未占据分子轨道能级差.对于DSSCs中新型高效Zn卟啉类光敏染料的分子设计和性能筛选具有很好的理论指导作用.     

含三唑基酰基硫脲类除草剂的结构与生物活性的量子化学研究

利用量子化学方法,对14种含三唑基酰基硫脲类化合物的结构与除草活性关系进行了研究.采用HF方法和6-31G基组,对14种化合物进行全参数优化,得到了它们的稳定构型.并对化合物中原子的净电荷分布、前线分子轨道能级及轨道组成等性质进行了分析,把它们与试验得到的生物活性数据对照,通过研究发现,三唑基酰基硫脲类化合物的除草活性与分子的前线轨道(HOMO、LUMO)能级存在一定的关系.     

有机化合物的构性相关分析Ⅰ.烯烃和炔烃的构性相关分析

阐述了烯烃和炔烃分子中的 π-分子轨道 ,并且根据有机化合物的构性相关理论对烯烃和炔烃进行了系统的构性相关分析。经过分析将烯烃和炔烃的化学性质归纳成为 3大类 :官能团的反应 ,烃基的反应和端基炔的特殊反应 ,从而增强了烯烃和炔烃化学的规律性和科学性。     

有机化合物的构性相关分析Ⅱ.苯的构性相关分析

用 HMO法简明地描述了苯的π分子轨道。计算说明 ,由于苯分子的 6个 p轨道形成环状大π键后具有了 2β的离域能 ,致使苯环在化学上具有高度的稳定性。同时 ,在构性相关理论的指导下对苯进行较系统的构性相关分析。结果表明 ,苯的环状大π键结构不仅使苯成为 1个 L ewis碱 ,而且使苯容易发生卤代、硝化、磺化等亲电取代反应 ,但不易发生加成反应。     

密度泛函方法对外电场作用下NaH 分子结构和激发特性的研究

采用密度泛函(DFT)方法,运用LSDA对不同外电场(-10.2845×109~10.2845×109 V/m)中基态NaH 分子进行理论计算,得到了它的几何参数、电荷分布、电偶极矩、最高占据轨道能级、最低空轨道能级.采用杂化 CIS-DFT方法(CIS-LSDA),在同样的外电场作用下,计算了NaH 分子的激发能、波长和振子强度.结果表明, NaH 分子结构强烈地依赖着外电场,且变化规律对电场方向呈现非对称性,外电场改变了NaH 分子激发态出现的 顺序和电子跃迁光谱强度.     

有机化合物的构性相关分析Ⅰ.烯烃和炔烃的构性相关分析

阐述了烯烃和炔烃分子中的π－分子轨道，并且根据有机化合物的构性相关理论对烯烃和炔烃进行了系统构性相关分析。经过分析将烯烃和炔烃的化学性质归纳成为3大类，官能团的反应，烃基的反应和端基炔的特殊反应，从而增强了烯烃和炔烃化学的规律性和科学性。     

有机化合物的构性相关分析Ⅱ.苯的构性相关分析

用ＨＭＯ法简明地描述了苯的π分子轨道。计算说明，由于苯分子的６个ｐ轨道形成环状大π键后具有２β的离域能，致使苯环在化学上具有高度的稳定性。同时，在构性相关理论原指导下对苯进行较系统的构性相关分析。结果表明，苯的环状大π键结构不仅使苯成为１个Ｌｅｗｉｓ碱，而且使苯容易发生卤代、硝化、磺化等亲电取代反应，但不易发生加成反应。     

共轭环烯芳香性的极限研究

用点群研究共轭环烯分子结构，假定共轭环烯所有的碳原子都在同一平面上，把分子简化为几何图形，再应用于点群，则分子的对称性与分子所属点群的对称操作数目成正比例关系，并以平均每个π电子对称操作数目的自然对数作为芳香性量度标准，然后用最小二乘法处理。这样半定量地计算共轭环烯的芳香性及其极限，其计算方法比ＨＭＯ法简单直观，且其计算结果与客观现实完全符合。     

A 160-femtosecond optical image processor based on a conjugated polymer

Degenerate ground-state conjugated polymers exhibit large third-order nonlinear optical susceptibilities, including substantial two-photon absorption. With the use of a machine architecture suited to these material properties, ultrafast optical processors are possible. A four-wave mixing optical correlator was built with an air-stable, processable, degenerate ground-state conjugated polymer, poly(1,6-heptadiester). The continuously updatable processor correlates two 5000-pixel images in less than 160 femtoseconds, achieving peak processing rates of 3 x 10(16) operations per second.     

The second ring-moon system of Uranus: discovery and dynamics

Deep exposures of Uranus taken with the Hubble Space Telescope reveal two small moons and two faint rings. All of them orbit outside of Uranus's previously known (main) ring system but are interior to the large, classical moons. The outer new moon, U XXVI Mab, orbits at roughly twice the radius of the main rings and shares its orbit with a dust ring. The second moon, U XXVII Cupid, orbits just interior to the satellite Belinda. A second ring falls between the orbits of Portia and Rosalind, in a region with no known source bodies. Collectively, these constitute a densely packed, rapidly varying, and possibly unstable dynamical system.     

Verification of Earth's "Pear Shape" Gravitational Harmonic

Predictions of the orbit of the Transit 1B satellite were systematically in error until account was taken of a third-order gravitational harmonic. The amplitude deduced for this harmonic by O'Keefe from the Vanguard I orbit serves very well, even though the orbits and the methods of observation and orbit fitting for the two satellites are quite different.     

Entwined and parallel bundled orbits as alternative models for narrow planetary ringlets

Particle orbits can be bundled in two different ways to produce narrow, Uranus-type ringlets. The usual assumption is that they are packed in a parallel manner in a structure that is essentially only two-dimensional, but it is then difficult to explain the large numbers of particles per unit area of the ring plane that are inferred from the observations. The alternative of a bundle of entwined orbits produces a three-dimensional structure of potentially large projected areal density. A start has been made in identifying possible mechanisms for stabilizing these structures, but much remains to be done, particularly for the less-studied model of entwined orbits. The two models might be discriminated observationally by differences in the motion of the line of intersection of the orbital and equatorial planes, and by the predicted radial reversal (entwined) or nonreversal (parallel) of features in occultation signatures taken at certain longitudes.     

Multiplex spectroscopy: determining the transition moments and absolute concentrations of molecular species

A procedure is described that uses two spectroscopic techniques, absorption and infrared degenerate four-wave mixing, in tandem (multiplex) to measure the transition dipole moments and absolute concentrations of molecular species in situ. The method is demonstrated by the measurement of the relative transition moments and concentrations of two dissimilar sample gas components, hydrogen chloride and nitrogen dioxide, but is applicable to a wide variety of molecules and, thus, can provide new information for transient molecular species. Further, difficulties in obtaining quantitative information through techniques such as laser-induced fluorescence, coherent anti-Stokes Raman scattering, and degenerate four-wave mixing spectroscopies can be overcome when a multiplex approach is used.     

Stellar motion survey by automation

The proper motion survey on plates taken with the 48-inch Schmidt telescope at Mount Palomar Observatory has now progressed to the point where some 250,000 new motions for faint stars have been measured, and 5,000 new white dwarfs and degenerate stars and 3,000 stars of low luminosity have been added.     

蜡质芽孢杆菌aiiA基因的克隆及融合表达

设计一对可扩增aiiA基因完整的开放阅读框的简并引物对aiiA1和aiiA2,通过PCR技术对3株蜡质芽孢杆菌(Bc)的aiiA基因进行检测.结果表明,它们均含有aiiA基因.利用pMD18-T克隆载体直接从GP7菌株的PCR产物中克隆了aiiA基因.测序结果表明,该基因(GenBank登录号:AY943831)由753个碱基组成,编码含有250个氨基酸残基的蛋白质.该蛋白质推测的分子质量为28 ku,等电点约4.235.核苷酸序列的BLAST分析结果表明,与之同源性较高的基因均为Bc组aiiA基因(87%-99%).在氨基酸序列多重比较的基础上,应用PHYLIP软件构建了A iiA蛋白的系统发育树.此外,利用原核融合表达载体pMXB10初步研究了A iiA、几丁质结合蛋白(CBD)及Inte in融合蛋白诱导表达的情况.     

Electrical resistance of long conjugated molecular wires

The charge transport mechanism of a wire can be revealed by how its electrical resistance varies with length. We have measured the resistance and current-voltage characteristics of conjugated molecular wires ranging in length from 1 to 7 nanometers, connected between metal electrodes. We observe the theoretically predicted change in direct-current transport from tunneling to hopping as a function of systematically controlled wire length. We also demonstrate that site-specific disruption of conjugation in the wires greatly increases resistance in the hopping regime but has only a small effect in the tunneling regime. These nanoscale transport measurements elucidate the role of molecular length and bond architecture on molecular conductivity and open opportunities for greater understanding of electrical transport in conjugated polymer films.     

Jupiter: its captured satellites

Because of the small size and irregular orbits of the seven outer satellites of Jupiter, it is often assumed that they were derived by capture. The conditions whereby Jupiter can capture satellites have therefore been examined. Relationships derived on the basis of the three-body problem for planets in elliptical orbits enable the dimensions of the capture orbits around Jupiter to be calculated. It is found that Jupiter may capture satellites through the inner Lagrangian point when at perihelion or at aphelion. Captures at perihelion should give rise to satellites in direct orbits of 11.48 x 10(6) kilometers and capture at aphelion to retrograde orbits of 21.7 x 10(6) kilometers. The correspondence with the seven outer satellites suggests that Jupiter VI, VIl, and X in direct orbits at 11.47, 11.74, and 11.85 x 10(6) kilometers were captured at Jupiter perihelion, whereas Jupiter VIII, IX, XI, and XII in retrograde orbits of 23.5, 23.7, 22.5, and 21.2 x 10(6) kilometers were captured when Jupiter was at aphelion. Examination of the precapture orbits indicates that the seven outer satellites were derived from the asteroid belt.     

FLUORESCENT, ELECTRON MICROSCOPIC, AND IMMUNOELECTROPHORETIC STUDIES OF LABELED ANTIBODIES

Antibodies, produced in rabbits, to each of three bacterial species have been doubly labeled with fluorescein and ferritin. Irrespective of which label was conjugated to the antibody first, immunologic activity was maintained. Moreover, these preparations gave as high a degree of specificity in fluorescent and electron microscopic studies as did singly labeled antibodies. Immunoelectrophoretic analyses and other immunologic tests further confirmed that the antibodies were conjugated to both labels without loss of specific activity. The technique thus permits the relatively simple method of immunofluorescence to be used as an aid in selecting optimtum ferritin antibody conjugates for localizing of antigen at the molecular level by means of electron microscopy.