Fabrication of suspended graphene devices and their electronic properties

Suspended graphene devices are successfully fabricated by using a novel PMMA/MMA/PMMA tri-layer resist technique. The gap between graphene and dielectric substrate can be easily controlled by the thickness of the bottom PMMA layer, and no wet-etching with hazardous hydrofluoric acid is involved in our fabrication process. Electrical characterizations on suspended graphene devices are performed in vacuum when in-situ current annealing directly leads to a significant improvement on transport properties of graphene, i.e., the increase of carrier mobility with the reduction of width of Dirac peak. Our results make a new opportunity to study intrinsic properties of graphene.     

基于Benson-Carlson商环的双Frobenius代数的构造

设H为有限维球面(spherical)Hopf代数,r(H)为H的Green环,P为量子维数为0的H-模的同构类生成的r(H)的理想.本文利用可除(negligible)态射空间的维数在r(H)上定义了一个双线性型.该双线性型为结合、对称双线性型并且双线性型的根为r(H)中某中心元的零化理想.然后讨论了Green环r(H)的一类商环,即所谓的Benson-Carlson商环r(H)/P.该商环可以视为H-模范畴的一类商范畴的Green环.进一步,如果H作为代数还是有限表示型的,那么Benson-Carlson商环r(H)/P具有类群代数和双Frobenius代数结构.     

1,6-亚甲基桥[10]轮烯并[3,4-g]-蒽醌衍生物的合成

采用无溶剂合成法,以1,6-亚甲基桥[10]轮烯-3,4-二甲酸酐为原料,Zr OCl2·8H2O/Na Cl为催化剂,于165℃下分别与取代苯经Friedel-Crafts缩合反应合成了4个新型的1,6-亚甲基桥[10]轮烯并[3,4-g]-蒽醌衍生物,其结构经1H NMR,13C NMR,IR,MS和HR-MS表征。     

A FIXED POINT APPROACH TO THE STABILITY OF A GENERALIZED APOLLONIUS TYPE QUADRATIC FUNCTIONAL EQUATION

Using the fixed point method, this article proves the Hyers-Ulam-Rassias stability of a generalized Apollonius type quadratic functional equation in Banach spaces. The conditions of these results are demonstrated by the quadratic functional equation of Apollonius type.     

TWO POINTS BOUNDARY VALUE PROBLEMS IN BANACH SPACES

（王志华）（张凤祥）ＴＷＯＰＯＩＮＴＳＢＯＵＮＤＡＲＹＶＡＬＵＥＰＲＯＢＬＥＭＳＩＮＢＡＮＡＣＨＳＰＡＣＥＳ￥ＷａｎｇＺｈｉｈｕａ；ＺｈａｎｇＦｅｎｇｘｉａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ．ＬａｎｚｈｏｕＵｎｉｖｅｒｓｉｔｙ．Ｌａ...     

小波分析在圆柱壳结构损伤检测中的应用研究

为了检测出圆柱壳中的裂纹引起的损伤,利用sym4小波,对含裂纹圆柱壳的应变能曲线进行连续小波变换和多分辨分析,从小波系数出现局部模极大值来识别损伤的存在以及裂缝位置。通过分析和计算获得满意结果,表明此方法在圆柱壳结构损伤诊断中具有较高的应用价值。     

反分析法在泡沫金属材料动态性能实验中的应用

在实验测试泡沫金属材料的动态性能时，由于其所具有的特殊性能使得传统的SHPB技术的采用遇到较大的困难。为了实验确定泡沫金属材料的初始动力坍塌强度和平台应力，研究其应变率效应，在现有SHPB实验装置的基础上,利用反分析法中的反卷积技术，通过计算机模拟给出了该实验装置的传递函数，完善了SHPB实验的数据处理系统，为实验研究泡沫材料的动态特性提供了一种有效的方法。     

泡沫铝合金动态力学性能实验研究

利用分离式霍布金森压杆(SHPB)实验技术和MTS材料实验机对两组不同孔径、不同密度的开孔泡沫铝合金进行了准静态和动态压缩实验研究。实验结果表明:泡沫铝合金的静态和动态变形过程均具有泡沫材料变形的三个阶段特征。开孔泡沫铝合金的变形是均匀变化过程，并不出现局部的变形带。与相对密度对力学性能的影响相比，孔径大小的影响可以忽略不计。在考察的应变率范围内，屈服应力对应变率并不很敏感。     

PYG荧光屏及其应用

本文介绍了彩色飞点管用的铈激活镓铝酸钇——Y_3(Al,Ga)_5O_(12)∶Ce荧光体的亮度,分辨率、噪音、老化等特性,并与以往使用的超短余辉荧光体作了比较;概述了具有PYG荧光屏飞点管的新的应用。     

A STRATEGY FOR ISOLATING DIFFERENTIATIONINDUCING COMPLEMENTARY DNAs FROM HUMAN ESOPHAGEAL CANCER CELL LINE TREATED WITH RETINOIC ACID

Treatment of the human esophageal cancer cell line EC8712 with retinoic acid (RA) stopped the cell growth significantly and gave rise to terminal differentiation of the cells characterized by increased expression of involucrin gene. Two cDNA libraries were constructed from the parental and RA-treated cells respectively. Repeated subtractive hybridization of single-stranded plasmid DNA prepared from pooled colonies of cDNA library of the parental cells with cDNA probe generated from the RA-treated cells exhausted sequences common to both libraries of the cell. The unhybridized cDNA probe represented, therefore, the genes activated after RA-treatment. By using these enriched cDNAs as probe to screen the cDNA library constructed from the RA-treated cells thirty-nine positive colonies were obtained, of which two were specifically due to RA-induction. One of these two cDNA clones, designated as pRA538, has undergone further analysis and shown differentiation-inducing effect on parental cancer cells. A novel