Model and empirical study on some collaboration networks

In this paper we present an empirical study of a few practical systems described by cooperation networks, and propose a model to understand the results obtained. We study four non-social systems, which are the Bus Route Networks of Beijing and Yangzhou, the Travel Route Network of China, Huai-Yang recipes of Chinese cooked food, and a social system, which is the Collaboration Network of Hollywood Actors. In order to explain the results related to the degree distribution, act-degree distribution and act-size distribution (especially about the degree distribution, which may be better fitted using a stretched exponential distribution (SED)), we suggest a simple model to show a possible evolutionary mechanism for the emergence of such networks. The analytic and numerical results obtained from the model are in good agreement with the empirical results.     

Kerr介质中级联三能级原子与压缩相干态相互作用的光子统计演化

本文研究了存在Kerr介质的高Q腔中压缩相干态与级联三能级原子相互作用的光子统计演化规律,讨论了光场参数、Kerr介质及相干振幅对平均光子数的影响.     

胶束液相色谱／安培电化学检测尿样中的扑热息痛及4－氨基苯酚

用胶束液相色谱／安培检测器检测尿样中的扑热息痛及其主要水解产物４－氨基苯酚。采用１４．５μｍ的碳纤维电极作为工作电极，以高于临界胶束浓度的阴离子表面活性剂十二烷基磺酸钠（ＳＤＳ）作为液相色谱的流动相，尿样直接进样分析，扑热息痛和４－氨基苯酚的检测限分别为０．１３ｎｍｏｌ／Ｌ及０．７３ｎｍｏｌ／Ｌ（Ｓ／Ｎ＝２）。     

A study of a possible unified potential model

The various properties of quarkonium systems have been studies in the framework of a recently proposed potential model, which combines the asymptotic freedom at the largeQ ₂ and the multigluon effect at the lowerQ ₂ regions with the confinement at the large distance. Good agreements with experiments are found, including \(c\bar c\) and \(b\bar b\) energy levels, leptonic decay widths, and in particular the fine and hyperfine splittings. We also analyze the Lorentz structure of the confinement potential with reference to the charmonium and bottomium fine and hyperfine splittings. Our analyses conclude that almost pure scalar confinement is favored. The properties of \(t\bar t\) spectroscopies are studied over a wide range of \(M_{t\bar t}\) values (from 80 GeV to 200 GeV).     

Bombieri's theorem in short intervals

The well-known Bombieri-A. I. Vinogradov theorem states that (1) $$\sum\limits_{q \leqslant x^{\tfrac{1}{2}} (\log x)^{ - s} } {\mathop {\max }\limits_{(a,q) = 1} \mathop {\max }\limits_{y \leqslant x} } \left| {\psi (y,q;a) - \frac{y}{{\varphi (q)}}} \right| \ll \frac{x}{{(\log x)^A }},$$ whereA is an arbitrary positive constant,B=B(A)>0, and as usual, $$\psi (x,q;a) = \sum\limits_{\mathop {n \leqslant x}\limits_{n = a(q)} } {\Lambda (n),}$$ Λ being the Von Mangoldt's function. The problem of finding a result analogous to (1) for short intervals was investigated by many authors. Using Heath-Brown's identity and the approximate functional equation for DirichletL-functions, A. Perelli, J. Pintz and S. Salerno in 1985 established the following extension of Bombieri's theorem: Theorem 1. (2) $$\sum\limits_{q \leqslant Q} {\mathop {\max }\limits_{(a,q) = 1} \mathop {\max }\limits_{h \leqslant y} \mathop {\max }\limits_{\frac{x}{2}< \approx \leqslant x} } \left| {\psi (z + h,q;a) - \psi (z,q;a) - \frac{h}{{\varphi (q)}}} \right| \ll \frac{y}{{(\log x)^A }}$$ where A>0 is an arbitrary constant,y=x ^θ $$\frac{7}{{12}}< \theta \leqslant 1, Q = x^{\frac{1}{{40}}} .$$ ,Q=x ^1/40. By improving the basic lemma which A. Perelli, J. Pintz and S. Salerno used as the main tool to prove Theorem 1, we obtain Theorem 2.Under the same condition as in Theorem 1,for Q=x ^1/38.5, (2)still holds.     

热活化延迟荧光聚合物及其电致发光器件

热活化延迟荧光(TADF)聚合物,不仅具有小分子TADF材料高的激子利用效率特性,而且还具备分子多样性好、可溶液加工、低成本、以及易实现大面积柔性器件等诸多优势,在近几年受到广泛的关注并展现了良好的应用前景。本文从TADF聚合物分子设计原理、器件结构及发光机理出发,依据TADF聚合物的构筑方法不同,概括了其结构设计策略,详述了各种类型TADF聚合物的分子结构和光电性能及其在有机电致发光器件领域应用的研究进展,最后探讨了TADF聚合物存在的问题,并展望了其发展前景。     

异核双金属有机化合物的合成方法与反应性能研究

本文对近年来异核双金属有机化学的发展作了简要的介绍和回顾, 文中对含金属-金属键和不含金属-金属键的d/d和d/f异核双金属有机化合物的合成方法及反应性能作了归纳。     

THE AROMATIZATION MECHANISM OF METHANE OVER Mo/HZSM-5 ZEOLITE CATALYSTS WITHOUT USING OXIDANTS

IntroductionMethancisthcmaJorcomponcntofnaturalgasanditscatalyticconvcrsiontodcsiredchemicalproductsorliquidfiJcIisnotonl}'apromisingapproachtotheutilizationofnaturalgasrcsourccbutalsoagrcatsubjcctforcatalysissciencctt'hichdcaIst"iththcactivationofsmallmolcculesThcx"orldrcscrvcofnaturalgashasbccnexplorcdasaboutl382562xl()8m3IllTheMTGprocessdcvclopedbythcMobilcorpcangctliquidfuelfrommethancthroughsteamreformingofmethanctoproduccsynthcsisgaswhichisassociatedt'ithamaJorityofthecostsofthcprocc…     

The preparation of nano‐scope chitosan‐oligomer copper complexes and their interaction with DNA

Water‐soluble low molecular weight chitosan of nanometer level and its copper complexes were prepared, and characterized by IR spectra, elemental analysis and gel permeation chromatography (GPC). The modes and mechanism of these copper complexes interaction with DNA were studied by a fluorescent probe method and electrophoresis analysis. It is suggested that there are electrostatic and intercalation modes of copper complexes interacting with DNA. At first, the cationic complex electrostaticly binds to the negatively charged phosphate backbone of DNA, and then a portion of the complex intercalates between the base pairs on the DNA duplex strand. Copyright © 2005 John Wiley & Sons, Ltd.