西平铁路彬县下沟煤矿采空区方案研究

由于下沟煤矿的开采造成西平铁路隧道等工程下部存在采空区,为保证西平铁路的顺利建成,有必要对采空区线路方案进行研究.通过对采空区方案研究的详细阐述,在无法完全避开采空区的条件下选择较合理的线路方案通过采空区.     

线性动态系统的可控性判别

利用矩阵理论，对线性动态系统的可控性条件了讨论，并通过矩阵变换 的结果设法确定影响系统可控性的状态变量，因而在具体的系统控制中有一定应用价值。     

新媒体技术因子对高等教育影响分析

新媒体技术已对整个高校教学系统中教学结构、教学模式及教学手段等带来重大变革,那么新媒体技术到底对高校教育产生了多大的影响,这些影响反应在我们的现实生活当中又是什么样,本文简略对其相互影响进行了探讨。     

3-硝基-2-氯甲酰基苯甲酸乙酯的合成方法的改进

以3-硝基-2-羧基苯甲酸乙酯为起始原料,以五氯化磷为酰卤化剂,二氯甲烷为反应溶剂合成了3-硝基-2-氯甲酰基苯甲酸乙酯,产率达到95％.此方法简单方便,提高了产率,更适合工业化生产.     

Development of specialized farmer cooperatives typical inspiration

发展现代农业,既要靠现代物质技术装备,又要靠现代农业制度.国际经验表明,建设现代农业制度一个重要的方面,就是发展农业合作社.从现代农业制度角度上讲,农业现代化有赖于农业和农民的组织化.可以说,农民专业合作社是推进现代农业建设的一种有效组织形式,它是广大农民在家庭承包经营基础上,按照自愿、民主的原则,依托当地主导产业和特色产品开发而自发组建的互助合作体制形式,是增加农民收入、适应市场经济发展要求、提高农业整体素质、发展现代农业、构建农村和谐社会的重要内容,具有广泛的群众基础.     

非主修作曲专业“曲式与作品分析”课程教学特点研究

以高校非主修作曲专业"曲式与作品分析"课程为研究对象,对课程的性质、任务以及教学方式进行探讨,并结合教学经验对如何改进课程的教学提出一些看法。     

Corrigendum to "Research progress on electrical signals in higher plants"

The authors would like to inform the readers that in the above mentioned paper,the word "Loosestrife" on p.533,the ninth line of the left-hand column should be replaced by "Desmodium motorium".In addition,the cited references[48,54-58]in the last sentence of the fourth paragraph of Section 3.3 "Patch-clamp recording technique" should be replaced by[48,54-57].The authors would like to apologize to the readers for these errors.     

Preparation of N-doped porous carbons via high internal phase emulsion template

Heteroatom doped porous carbon materials have great application prospects in supercapacitors. In the present study, an approach of preparing N-doped porous carbon(NPC) was proposed from porous poly(resorcinolformaldehyde-melamine) monoliths which were prepared by high internal phase emulsion(HIPE) template.Melamine was dissolved in the external phase and copolymerized, acting as the N source and porous structure regulator to provide micropore-dominant NPCs. The structure, morphology, specific surface area(SSA), and chemical composition of the samples were systematically studied. With melamine content increasing, N-doping content in NPC increased while the SSA of NPC increased at first and then decreased. When the content of N is 8.42 wt%, the obtained NPC showed the highest SSA of about 1670 m~2 g~(-1). Furthermore, high N doping content could improve the electronic conductivity and provide additional pseudocapacitance of NPC. Under the combined influences of proper N content and high porosity, the prepared NPC electrodes revealed excellent specific capacitance(228.0 Fg~(-1) at 1.0 A g~(-1), favorable circling stability, and prominent rate capability in a threeelectrode system with 6 M KOH solution as the electrolyte.     

Complete genome sequence of Salmonella enterica serovar Typhimurium LT2.

Salmonella enterica subspecies I, serovar Typhimurium (S. typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever. The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year. Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S. typhimurium strain LT2. The distribution of close homologues of S. typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S. enterica serovar Paratyphi A (S. paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S. typhimurium LT2 genes. Lateral transfer of genes is frequent, with 11% of the S. typhimurium LT2 genes missing from S. enterica serovar Typhi (S. typhi), and 29% missing from Escherichia coli K12. The 352 gene homologues of S. typhimurium LT2 confined to subspecies I of S. enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis. Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.     

如何脚踏实地当好一名小学教师

弹指一挥间,育人三十年.当我们把点点滴滴的心血化为浇灌花朵的雨露时,我们惊喜地听见了花开的声音.它告诉我:脚踏实地当好一名小学教师是真实的、是快乐的、是幸福的、是永恒的……