Hardy空间上某些解析Toeplitz算子的换位及约化子空间

讨论了Hardy空间上以非退化有界单叶解析函数的幂为符号的解析Toeplitz算子的换位.并且刻划了符号为三个Blaschke因子积的解析Toeplitz算子的约化子空间.     

Frame wavelets in subspaces of

Let be a real expansive matrix. We characterize the reducing subspaces of for -dilation and the regular translation operators acting on We also characterize the Lebesgue measurable subsets of such that the function defined by inverse Fourier transform of generates through the same -dilation and the regular translation operators a normalized tight frame for a given reducing subspace. We prove that in each reducing subspace, the set of all such functions is nonempty and is also path connected in the regular -norm.

     

铅芯橡胶耗能器与油阻尼器组合耗能系统的振动台试验与分析

在一座三层单跨的钢结构模型中安装了铅芯橡胶耗能器及其和油阻尼器并联组合。对这两种耗能体系进行了振动台试验,以研究组合耗能体系的动力特性,检验其减振效果,试验结果表明：组合耗能体系对位移和加速度有良好的减振效果;在合适的刚度范围内,增加适当的阻尼可提高耗能器的减振效果,进行了数值分析,并与试验结果进行了比较,验证了本文提出的计算模型与方法的正确性。     

New Segmented Copolymers by Combination of Atom Transfer Radical Polymerization and Ring Opening Polymerization

Atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP) were combined to synthesize various polymers with various structures and composition. Poly(ε-caprolactone)-b-poly(n-octadecyl methacrylate), PCL-PODMA, was prepared using both sequential and simultaneous polymerization methods. Kinetic studies on the simultaneous process were performed to adjust the rate of both polymerizations. The influence of tin(II) 2-ethylhexanoate on ATRP was investigated, which led to development of new initiation methods for ATRP, i.e., activators (re)generated by electron transfer (AGET and ARGET). Additionally, block copolymers with two crystalizable blocks, poly(ε-caprolactone)-b-poly(n-butyl acrylate)-b-poly(n-octadecyl methacrylate), PCL-PBA-PODMA, block copolymers for potential surfactant applications poly(ε-caprolactone)-b-poly(n-octadecyl methacrylate-co-dimethylaminoethyl methacrylate), PCL-P(ODMA-co-DMAEMA), and a macromolecular brush, poly(hydroxyethyl methacrylate)-graft-poly(ε-caprolactone), PHEMA-graft-PCL, were prepared using combination of ATRP and ROP.     

Asymmetry in transitional pipe flow of drag-reducing polymer solutions

New experimental data are presented and discussed for fully developed pipe flow of shear-thinning, viscoelastic polymer solutions in the transitional regime between laminar and turbulent flow. The data confirm that such transitional flows exhibit significant departures from axisymmetry in contrast to the fully developed pipe flow of Newtonian fluids or both laminar and turbulent flows of such drag-reducing liquids. The azimuthal structure of the asymmetry is investigated together with its axial development and also the velocity fluctuation levels. These data do not lead to an explanation for the asymmetry but do suggest that the influence of the flow geometry both upstream and downstream can be ruled out.     

NbSe2纳米材料的合成及减摩性能研究

将Se粉和Nb粉按一定的比例混合,然后密封在石英管中或压成片状后密封于石英管中,加热到一定温度,分别获得了NbSe2纳米纤维和NbSe2纳米颗粒.采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对所得产物进行了表征,分析了其微观形貌;采用MS-T3000摩擦磨损试验机测定了纳米颗粒作为基础润滑油N40添加剂的摩擦学性能.结果表明,制备的纳米纤维直径100～200nm,纳米颗粒直径40～300nm,二者都具有层状结构和良好的结晶性;NbSe2纳米颗粒作为润滑油添加剂具有明显优于基础润滑油的极压减摩性能;同纳米纤维相比,纳米颗粒的减摩性能较好.     

Pulse radiolysis study of rapid electron transfer from electron adduct and reducing OH adduct of dAMP to riboflavin and flavin adenine dinucleotide (FAD)

Rapid electron transfer from electron adduct and reducing OH adduct of 2'-deoxyadenosine-5'-monophosphate acid (dAMP) to riboflavin (RF) and flavin adenine dinudeotide (FAD) was studied using the time-resolved pulse radiolysLs techniques. Both spectroscopic and kinetic analyses showed that transient absorption spectrum of electron adduct or OH adduct of dAMP formed at first, and then changed to that of radical anion of RF or FAD after several microseconds of pulse. The evidence indicated that electron transfer from electron adduct and reducing OH adduct of dAMP to RF or FAD did occur. From buildup or bleaching kinetics of radical anions of RF and FAD, the rate constants for electron transfer were determined, respectively.     

Coherent Solution‐phase Synthesis of a Germanium‐Graphitic Nanocomposite and Its Evaluation for Lithium‐Ion Battery Anodes: Non‐innocent Role of the Mashima Reagent

The organosilicon reagent 1,4‐bis‐(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene 2 plays the binary role of the simultaneous reduction of GeCl₂.dioxane 1 dissolved in oleylamine to Ge nanocrystals and the formation of graphitic sheets under hot‐injection conditions. This colloidal synthetic route to germanium nanocrystals embedded on N‐doped graphitic nanosheets Ge/NG is free of any template or catalyst and involves easy purification techniques. The Ge/NG/C obtained after carbonization has been explored for anode performance in lithium‐ion batteries. Both Ge/NG and Ge/NG/C can be obtained on a gram scale and are bottleable under argon for months.     

Development of an Amperometric Microbial Biosensor Based on Thiobacillus thioparus Cells for Sulfide and Its Application to Detection of Sulfate‐Reducing Bacteria

This paper describes a novel electrochemical microbial biosensor based on Thiobacillus thioparus cells for sulfide detection. The morphology and electrochemical properties of the proposed biosensor were characterized by SEM and cyclic voltammetry, respectively. Working conditions of the microbial biosensor were optimized to obtain good electrochemical performances. Under the optimum conditions, analytical performances were evaluated, and the results suggested that the microbial biosensor could be used for selective detection of sulfide. The microbial biosensor was then successfully applied in detection of sulfate‐reducing bacteria by oxidizing its characteristic metabolite, sulfide, which was accumulated in culture media during bacterial growth.