弱闭T(N)-模的预零化子的等距映射

本文刻划了弱闭T(N)-模的预零化子间的等距映射.设u,W分别为由左连续序同态N→~N和N→~N所确定的弱闭T(N)-模, u(?),W(?)分别为u,W的预零化子,Φ为由u(?)到W(?)上的线性等距映射.若(0)*=(0)#=(0),dim(0)+≠1且min{dim(H(?)~H),dim(He(?)^H)}≥2,则存在酉算子Ui,Vi(i=1,2),使得Φ(A)=U1AV*1或Φ(A)=U2A*V2*.     

Acyclic edge coloring of triangle-free 1-planar graphs

A proper edge coloring of a graph G is acyclic if there is no 2-colored cycle in G. The acyclic chromatic index of G, denoted by χ a(G), is the least number of colors such that G has an acyclic edge coloring. A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, it is proved that χ a(G) ≤Δ(G) + 22, if G is a triangle-free 1-planar graph.     

九种Salen型多齿新配体的合成

利用乙二胺及其衍生物的Mannich反应在无催化剂的条件下合成了9种Salen型新的配体,化合物1和2在无溶剂条件下合成,化合物3a～3g在Salen配体中引入呋喃杂环,对其与金属的配位提供了多种可能性.所得化合物结构经元素分析,IR,MS,1H NMR等确认,同时用X射线单晶衍射测定了化合物1和3b的晶体结构.     

Synthesis and Esterification of 3‐Ferrocenyl Acrylic Acid in Ionic Liquid

3‐Ferrocenyl acrylic acid, synthesized from ferrocenecarboxaldehyde and propandioic acid in water‐insoluble ionic liquid (1‐butyl‐3‐methylimidazolium hexafluorophosphate, [BMIM]PF₆) at 85 °C in high yield, was transformed to a series of 3‐ferrocenyl acrylate of alcohols and phenols in water‐soluble ionic liquid (1,3‐dimethylimidazolium dimethylphosphate, [DMIM]Me₂PO₄) at room temperature in the presence of dicyclohexylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP).     

Two-dimensional electron transport in AlGaN/GaN heterostructures

We present a theoretical study of electron transport properties of two-dimensional electron gas in AlGaN/GaN heterostructures. By assuming a drifted Fermi–Dirac distribution and taking into account all major scattering mechanisms, including polar optical and acoustic phonons, background impurities, dislocation and interface roughness, the momentum- and energy-balance equations derived from Boltzmann equation are solved self-consistently. The dependence of the electron drift velocity and electron temperature as a function of the applied electric field are obtained and discussed.     

殷钢中零热胀系数的微观机制

18 97年 ,瑞士物理学家Ｃ .Ｅ .Ｇｕｉｌａｕｍｅ发现了一种奇妙的合金———在室温附近的一个很宽的温度范围内 ,合金的热膨胀系数几乎等于零 .这种合金的组成是 6 5%Ｆｅ和 35%Ｎｉ;呈面心立方结构 ,它的中文名字叫殷钢 ,英文名字是ｉｎｖａｒ,意思是体积不变(ｉｎｖａｒｉａｂｌｅ) .与ｉｎｖａｒ类似 ,Ｇｕｉｌａｕｍｅ还发展了所谓ｅｌｉｎｖａｒ合金 ,加热时合金的弹性 (ｅｌａｓｔｉｃｉｔｙ)不变 ,因而被用于制造钟表游丝 .192 0年 ,Ｇｕｉｌａｕｍｅ因上述发现被授予诺贝尔物理奖 .今天 ,殷钢最重要的应用是 :用来制造彩色电视机显…     

Durable antimicrobial cotton fabric fabricated by carboxymethyl chitosan and quaternary ammonium salts

Cellulose - In this article, carboxymethyl chitosan (CMC) and (3-carboxypropyl) trimethylammonium chloride (CPTC) were used as raw materials to prepare an antibacterial cotton fabric with excellent...