Fluorescence of acridinic dyes in anionic surfactant solution

The interaction of the cationic dyes acridine, 9-aminoacridine (9AA), and proflavine, with sodium dodecyl sulfate (SDS) was studied by electronic absorption, steady-state and time-resolved fluorescence spectroscopies. The dyes interact with SDS in the pre-micellar region leading in two cases to dimerization in dye-surfactant aggregates, but with distinct molecular arrangements. For proflavine, the observed red shift of the electronic absorption band indicates the presence of J-aggregate, which are nonfluorescent. In the case of 9AA, the aggregates were characterized as nonspecific (neither J- nor H-type is spectroscopically observed). The time-resolved emission spectra gives evidences of the presence of weakly bound dimers by the recovery of three defined decay times by global analysis: dye monomer (tau1 = 16.4 ns), dimer (tau2 = 7.1 ns), and a faster component (tau3 = 2.1 ns) ascribed to intracluster energy migration between monomer and dimer. Acridine has a weak interaction with SDS forming only an ion pair without further self-aggregation of the dye.     

Triton X-100在乙二醇中的胶体性质

表面活性剂在非水溶剂中聚集态的研究所见的报导与水体系相比要少得多．然而近年来对非水体系的研究日益增多．这是因为表面活性剂在非水溶剂中的应用日趋增加，但与水体系相反，对非水体系的性质了解甚少．对表面活性剂非水体系的研究还有助于对其聚集体的共溶剂效应有更深的认识．TritonX－100（以下简写为TX－100）是典型的非离子表面活性剂，在工业上有着广泛的应用．乙二醇在多醇中与水的化学结构最相近问，然而它却是水结构的破坏剂，加入少量的乙二醇会使水的冰点急剧下降．乙二醇又是蛋白质的变性溶剂．表面活性剂在乙二醇中的胶…     

1,3,5-三芳基-2-吡唑啉化合物光物理行为的研究

近年来，在分子内电荷转移化合物发光行为的研究中，对分子激发态非辐射衰变通道问题的研究有了较大的进展［‘－’］．在分子结构和所处环境两因素对激发分子非辐射衰变过程影响的研究中，在结构方面已经认识到如化合物分子内双键的特性、杂原子的存在以及分子的几何构象等都可能对化合物的发光行为带来很大影响［’－’1．特别是分子立体几何构象问题，自F6rster－Hoffmarm提出他们的模型以来同，最近迅速发展起来的所谓“扭曲的分子内电荷转移（TICT）”概念同，使分子构象问题在荧光、激光染料的光物理研究中占有十分重要的位置．按…     

Molecular Exciton Approach to Anisotropic Absorption and Circular Dichroism II. The Partial Optic Axis and its Application in Molecular Exciton Theory

Summary. The first part of the present communication develops the general theory of the partial optic axis, which is an excitation specific structural feature first proposed as an aid to the choice of chromophoric reference points in a molecular exciton approach to optical rotatory power, and discusses its applicability to symmetry analyses in the light of the distinction between the three categories for anisotropic optical rotatory power, i.e. chiral, achiral optically active, and achiral optically inactive molecular structures. The second part of the communication discusses the special role played by the concept of the partial optic axis in the evaluation of the anisotropic chromophoric intensity contributions in a molecular exciton approach, in particular in relation to the use of the chromophoric symmetry for the systematic selection and characterization of the intensity contributions.Permanent address: Holmebjerg 5, DK-2950 Vedbæk, Denmark     

126Ce的EC/β＋衰变

利用187 MeV的40Ca离子轰击同位素靶92Mo,由熔合蒸发反应生成目标核126Ce。藉助氦喷嘴快速带传输系统和X-X-t与X-γ-t符合测量,首次建立了126Ce的EC/β＋衰变纲图。建议了可能属于126Ce一个高自旋同核异能态的衰变,其β衰变后布居在与126La的高自旋同核异能态相关的低位能级区,测定的半衰期是57（9）s。也建议了可能属于126Ce基态的衰变,其β衰变后布居在与126La的低自旋同核异能态相关的低位能级区,它的半衰期被测定为12（4）s。但偶-偶核126Ce存在高自旋同核异能态的物理原因还有待进一步探究。     

局部化学法合成K0.5Bi0.5TiO3片状晶粒及其反应机理研究

以含铋层状Bi4Ti3O12(BIT)晶粒作为反应前驱体, 通过熔盐环境下的局部化学反应法制备了片状钛酸铋钾(K0.5Bi0.5TiO3, KBT)陶瓷粉体晶粒. 分析结果表明, 所制备的KBT陶瓷晶粒平均直径约为15～20 μm, 厚度小于2 μm. 分析了由含铋层状型BIT向钙钛矿型KBT片晶转化的形成机制, 并讨论了反应路径对最终产物形貌的影响规律.     

Effects of concentration of nonionic surfactant and molecular weight of polymers on the morphology of anisotropic polystyrene/poly(methyl methacrylate) composite particles prepared by solvent evaporation method

The effects of the concentration of polyoxyethylene octylphenyl ether (OP-10) as a nonionic surfactant and the molecular weight of polymers (polystyrene (PS) and poly(methyl methacrylate) (PMMA)) on the morphology of anisotropic PS/PMMA composite particles were investigated. In the case of polymers with lower molecular weight (M _w ≈ 6.0 × 10⁴ g/mol), the PS/PMMA composite particles have dimple, via acorn, to hemispherical shapes along with the increase of the OP-10 concentration. On the other hand, when the polymers have higher molecular weight (M _w ≈ 3.3 × 10⁵ g/mol), the morphology of PS/PMMA composite particles changed from dimple, via hemispherical, to snowman-like structure while the concentration of OP-10 was increased. Furthermore, thermodynamic analysis was first simply made by spreading coefficients, and the results indicated that both the concentration of OP-10 aqueous solution and the molecular weight of polymers were very important to the final morphology of anisotropic composite particles.     

分子角动量定向布居的制备探测和它的碰撞弛豫

利用受激Ｒａｍａｎ泵浦,使线性分子Ｃ２Ｈ２选择性地制备振动态角动量定向布居参数Ａσ（１）达到０．７～０．８。并测定了角动量定向布居碰撞诱导的弛豫速率常数,采用园偏振的紫外激光诱导荧光方法,可表征分子角动量定向布居的制备和它的碰撞弛豫过程。     

Large global solutions to 3-D inhomogeneous Navier-Stokes equations slowly varying in one variable

Motivated by Chemin and Gallagher (2010) [8], we consider the global wellposedness to the 3-D incompressible inhomogeneous Navier-Stokes equations with large initial velocity slowly varying in one space variable. In particular, we proved that when the initial density is close enough to a positive constant, then given divergence free initial velocity field of the type , as that in Chemin and Gallagher (2010) [8] for the classical Navier-Stokes system, we shall prove the global wellposedness of (INS) for ? sufficiently small. The main difficulty here lies in the fact that we will have to obtain the L¹(R⁺;Lip(R³)) estimate for convection velocity in the transport equation of (INS). Toward this and due to the strong anisotropic properties of the approximate solutions, we will have to work in the framework of anisotropic type Besov spaces here.