关于电介质内部的极化电荷

本文人电磁场理论出发，导出各赂同性线性电介质内、极化电荷与极化率、极化率梯度、自由电荷、以及电场强度之间的普遍关系式，进而总结出不出现极化电荷的三种情况和出现极化电的四种情况，这是文献「１」，「２」，「３」涉及到而未统一解决的问题。     

新建本科院校改革与发展中应处理好的几对关系

新建本科院校在改革与发展过程中,必须站在历史的高度,运用可持续发展的观点来审视学校的发展战略,处理好近期利益与长远发展的关系.一方面要抓住高等教育大众化历史进程的机遇,扩大办学规模,加强专业建设,确立教学工作的中心地位,不断创新,努力增强办学实力;另一方面,要在高等教育大众化阶段,狠抓教学质量,加快学科建设,提高科研能力,规范管理,提升办学水平.     

Over-expression of an Arabi-dopsisd δ-OAT gene enhances salt and drought tolerance in transgenic rice

Riceisoneofthemostimportantcropsintheworld,sincemorethanhalfoftheworldspopulationisfedonrice(OryzasativaL.).Althoughmuchhasbeendoneonfoodsecurityforlong,osmoticstress,duetodroughtandsalinity,isstillthemostseriousfactorthataffectstheyieldofrice[1].Ithaslongbeenfoundthatplantsaccumulateosmolytestomaintainosmoticbalanceandtoprotectsubcellularstructures[2].Theseosmolytesaremainlysmallmolecularweightorganiccompoundsandproteinprotec-tants.Prolineisregardedasthemostwidely-distributedosmolyteandwitht…     

书院的教学特点对现代教学改革的启示

书院是我国古代特有的教育组织形式.既是教学活动的中心,又是学术研究的胜地.在教学特色上注重学生个性,提倡教学相长,在教育史上占有重要地位和作用.文章根据书院的教学特点提出了对现代教学改革的启示.     

当代中国高等学校学术权力与行政权力的关系

笔者根据知识经济的特征、大学在知识经济时代的特殊作用、学术权力与行政权力关系的历史演变、中国及中国高校在新的历史条件下不断发生的变化特别是面对知识经济和加入WTO后的机遇与挑战,分析了知识经济时代中国高校学术权力与行政权力的关系,提出了自己的见解.     

ispEXPER辅助课堂教学的作用

随着多媒体教学手段和各种辅助教学软件的引入,使课堂教学趋于多样化、现代化,灵活的教学方式使得学生一改往日的单纯听教师在黑板上讲解画图为黑板与计算机屏幕相结合,对于一些难以理解的概念,通过仿真与动画加深对内容的理解.……     

Detecting chimeric 5''''l3''''UTRs with cross-chromosomal splicing by bioinformatics

The 5'/3' UTRs of mRNA are crucial in transla-tional regulation, and several serious diseases are believed tobe associated with abnormal splicing of these parts of themRNA sequence. In this work a novel method which usessequence alignment database searching for detecting chi-meric 5'3' UTRs with cross-chromosomal splicing is reported.Eight highly credible instances of cross-chromosomal splic-ing have been found using this method, representing addi-tional confirmation of the existence of cross-chromosomalsplicing events provided by bioinformatics tools. Since noconserved motif has been found in any of the eight instances,and at the same time current prediction algorithms produceonly trivial secondary structures at the "splicing sites", it isnot possible to identify any specific signal leading to thesplicing.     

SPECIAL TOPICS:DMP brings about new design space for virtualization technology

Professors Wang and Luo and their group in the Department of Computer Science and Technology,Peking University (PKU),have re cently introduced a new memory virtualization technique called Dynamic Memory Paravirtualization (DMP).     

ALCAM/CD166 adhesive function is regulated by the tetraspanin CD9

ALCAM/CD166 is a member of the immunoglobulin superfamily of cell adhesion molecules (Ig-CAMs) which mediates intercellular adhesion through either homophilic (ALCAM–ALCAM) or heterophilic (ALCAM–CD6) interactions. ALCAM-mediated adhesion is crucial in different physiological and pathological phenomena, with particular relevance in leukocyte extravasation, stabilization of the immunological synapse, T cell activation and proliferation and tumor growth and metastasis. Although the functional implications of ALCAM in these processes is well established, the mechanisms regulating its adhesive capacity remain obscure. Using confocal microscopy colocalization, and biochemical and functional analyses, we found that ALCAM directly associates with the tetraspanin CD9 on the leukocyte surface in protein complexes that also include the metalloproteinase ADAM17/TACE. The functional relevance of these interactions is evidenced by the CD9-induced upregulation of both homophilic and heterophilic ALCAM interactions, as reflected by increased ALCAM-mediated cell adhesion and T cell migration, activation and proliferation. The enhancement of ALCAM function induced by CD9 is mediated by a dual mechanism involving (1) augmented clustering of ALCAM molecules, and (2) upregulation of ALCAM surface expression due to inhibition of ADAM17 sheddase activity.     

A large-cavity zeolite with wide pore windows and potential as an oil refining catalyst

Crude oil is an important feedstock for the petrochemical industry and the dominant energy source driving the world economy, but known oil reserves will cover demand for no more than 50 years at the current rate of consumption. This situation calls for more efficient strategies for converting crude oil into fuel and petrochemical products. At present, more than 40% of oil conversion is achieved using catalysts based on faujasite; this zeolite requires extensive post-synthesis treatment to produce an ultrastable form, and has a large cavity accessible through four 0.74-nm-wide windows and thus limits the access of oil molecules to the catalytically active sites. The use of zeolites with better accessibility to their active sites should result in improved catalyst efficiency. To date, two zeolites with effective pore diameters exceeding that of faujasite have been reported, but their one-dimensional pore topology excludes use in oil refining. Similarly, zeolites with large pores and a three-dimensional pore topology have been reported, but in all these materials the pore openings are smaller than in faujasite. Here we report the synthesis of ITQ-21, a zeolite with a three-dimensional pore network containing 1.18-nm-wide cavities, each of which is accessible through six circular and 0.74-nm-wide windows. As expected for a zeolite with this structure, ITQ-21 exhibits high catalytic activity and selectivity for valuable products in preliminary oil refining tests.