θ*r,s,t-图与唯一2-列表染色图的特征化

如果一个图G存在一个k-列表安排使得G具有一个唯一列表染色,则称 G是唯一列表可染色图,简称UkLC图．我们称图G具有M(k)性质当且仅当G不 是UkLC图．本文在借鉴θr,s,t-图概念的基础上引入θr,s,t-图的定义,并证明:除了 r=s=t=2以外,θr,s,t-图都是U2LC图．利用如上结果我们给出M．Mahdian and E．S．Mahmoodian对U2LC图所作特征化的一个简单证明．     

热电物理的研究进展

热电效应在发电，致冷方面有巨大的应用潜力，这些年来，人们为提高热电能量转换效率进行了不懈的努力，文章概述了从机理上提高材料热性能的一般途径，在此基础上，介绍了最近几年在氧化物超导体，ＴＰｎ３化合物，富硼固体等新材料体系中，以及在非均匀材料，复合型材料，量子阱结构等新形式材料中的研究结果。     

化学发光分析法测定绿原酸

本文基于碱性介质中绿原酸对鲁米诺-铁氰化钾化学发光体系的抑制作用,首次建立了绿原酸的化学发光分析法,并探讨了其作用机理。方便简便、迅速、重复性好、灵敏度高。采用该法可测定1.0×10-8g/ml～1.0×10-5g/ml范围内的绿原酸,其检出限达到5.2×10-9g/ml,回收率为104%.     

三十烷醇在GA_3影响水稻幼苗生长和生理性状中的增效作用

微量三十烷醇（ＴＲＩＡ）与ＧＡ３配合使用，比ＧＡ３单独使用能明显地促进幼苗生长和增加幼苗干物质积累．同时还增强了ＧＡ３对幼叶中叶绿素含量、可溶性蛋白质含量、呼吸速率、细胞膜透性和过氧化物酶活性的影响．ＧＡ３＋ＴＲＩＡ与ＧＡ３处理相比，促进幼叶内源ＧＡ３水平提高，稳定保持内源ＺＴ于一定水平，ＴＲＩＡ在ＧＡ３低浓度时降低ＩＡＡ水平，在高浓度时则提高ＩＡＡ水平．作者认为ＴＲＩＡ可作为ＧＡ３处理时的增效剂．     

XPS对离子交换法光色玻璃中银的状态研究

本文介绍利用ｘ射线光电子能谱分析仪（ＸＰＳ），对玻璃表面银的存在状态进行研究，实验结果表明银以Ａｇ＾０、Ａｇ＾＋、Ａｇ＾＋＋三种状态存在，而Ａｇ＾＋的存在有利于玻璃光色性的提高。文中并提出了在工艺过程中应采用惰性或弱氧化性气氛。     

声光技术在光纤系统中的应用

本文简要介绍了在光纤通信、光纤传感和光纤信号处理枝术等各种光纤系统中可能开发应用的固体声光技术和光纤声光技术。     

ASYMPTOTIC APPROXIMATION METHOD AND ITS CONVERGENCE ON SEMI-INFINITE PROGRAMMING

The aim of this article is to discuss an asymptotic approximation model and its convergence for the minimax semi-infinite programming problem. An asymptotic surrogate constraints method for the minimax semi-infinite programming problem is presented by making use of two general discrete approximation methods. Simultaneously, the consistence and the epi-convergence of the asymptotic approximation problem are discussed.     

Atom transfer radical polymerization directly from poly(vinylidene fluoride): Surface and antifouling properties

The direct preparation of grafting polymer brushes from commercial poly (vinylidene fluoride) (PVDF) films with surface‐initiated atom transfer radical polymerization (ATRP) is demonstrated. The direct initiation of the secondary fluorinated site of PVDF facilitated grafting of the hydrophilic monomers from the PVDF surface. Homopolymer brushes of 2‐(N,N‐dimethylamino)ethyl methacrylate (DMAEMA) and poly (ethylene glycol) monomethacrylate (PEGMA) were prepared by ATRP from the PVDF surface. The chemical composition and surface topography of the graft‐functionalized PVDF surfaces were characterized by X‐ray photoelectron spectroscopy, attenuated total reflectance/Fourier transform infrared spectroscopy, and atomic force microscopy. A kinetic study revealed a linear increase in the graft concentration of poly[2‐(N,N‐dimethylamino)ethyl methacrylate] (PDMAEMA) and poly[poly(ethylene glycol) monomethacrylate] (PPEGMA) with the reaction time, indicating that the chain growth from the surface was consistent with a controlled or living process. The living chain ends were used as macroinitiators for the synthesis of diblock copolymer brushes. The water contact angles on PVDF films were reduced by the surface grafting of DMAEMA and PEGMA. Protein adsorption experiments revealed a substantial antifouling property of PPEGMA‐grafted PVDF films and PDMAEMA‐grafted PVDF films in comparison with the pristine PVDF surface. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3434–3443, 2006     

Effect of glass bead packing on the fibrillation of liquid‐crystalline polymer in polycarbonate

Polycarbonate (PC) was melt blended with small amount of liquid‐crystalline polymer (LCP) and various contents of glass beads (GB) having different diameters. The rheological measurements indicated that the GB addition increased the viscosity ratio and seemed unfavorable to the LCP fibrillation. However, the morphological observation showed that the LCP fibrillation was promoted by the GB addition and varied with the GB packing. With the increased GB packing by increasing the GB content and/or decreasing the GB diameter, LCP deformed from spheres and ellipsoids into stretched ellipsoids at lower shear rates and into long fibrils at higher shear rates. Although higher content of smaller GB jammed into the larger LCP droplets and inhibited the LCP fibrillation, very long LCP fibrils formed at higher shear rates at a high enough packing of GB. The relationship between GB packing and LCP fibrillation revealed two kinds of hydrodynamic effects of GB promoting the LCP fibrillation: at lower GB packing, the shear flow was enhanced by the high local shear between GB, in quantity; and for a high enough GB packing, the shear flow was changed, in quality, into elongational flow, which was more effective for the LCP fibrillation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1020–1030, 2006     

一维问题的一种积分形式的流量重构算法

1引言我们考虑如下一维二阶椭圆边界值问题(-(β(x)p′)(x))′=f(x),x∈(a,b) p(a)=p(b)=0(1))其中β=β(x)是一恒正函数,且β∈H~1(a,b),f∈L~2(a,b)．事实上,在此条件下,我们可保证p∈H~2(a,b)(见[1],[2])．(1)之弱形式为：求p∈H_0~1(a,b)使得a(p,q)=(f,q),(?)q∈H_0~1(a,b),(2)其中a(p,q)=(?)_a~bβp′q′dx,(f,g)=(?)_a~bfqdx．给定(a,b)的一个分割α=x_0＜x_1＜…＜x_(n-1)＜x_n=b,令h=(?)(x_i-x_(i-1)),(?)_i表示通常相应于节点x_i的形状函数,即(?)_i是连续的分段线性函数且满足(?)_i(x_k)=δ_(ik),这里δ_(ik)=(?)i,k=0,1,…,n．又记V_h~0=span{(?)_1,(?)_2,…,(?)_(n-1)),取V_h~0作为p的逼近空间,则求解(1)的标准有限元格式为：求ph∈V_h~0使得