不断创新中的实验推断题

离子共存实验推断题是以实验操作和现象为主体,推断具体物质或离子共存的问题.这类题融基本概念和理论、元素化合物知识、计算技能于一体,考查面广、综合性强、思考容量大,能较好地考查考生对已学过的知识进行重组、转换、迁移推理以及分析综合能力.     

教育问题的价值辨识与生成

教育问题是研究主体与教育客体交互作用而建构、生成的。根据问题的不同维度,教育问题可划分为不同的类型。在教育研究中,除了要拒斥＂假＂问题、索解＂新＂问题外,其他类型的教育问题都难以进行价值区分,而要想提出有价值的教育问题,研究者则需要明确学术追求,守住学术良知;增强实践关怀,确立实践立场;加强学术交流,树立对话意识。     

一个代数不等式的再研究

《数学通报》2004年第4期刊登的1485号问题是：设xk〉0,k=1,2…n,p∈R,q〉0,且令∑k=1^n xk=s,Sk = pxk ＋ q（ s - xk）,     

创新:自学考试健康发展的必由之路

自学考试是我国高等教育的制度创新,它根植于我国优秀的教育考试传统,汲取了国际先进教育思想,缓解了人民群众对高等教育的迫切需求。20世纪末,我国加快高等教育改革和发展的步伐,高等教育的办学层次和形式更加多样化,自学考试的一些优势不再凸显。面对新的挑战,面对社会对教育的多样性需求,自学考试应适应高等教育改革需要,创新教育内涵,树立新的人才质量观,稳步发展学历教育,扩大非学历培训,充分利用现代信息技术平台,建设新型教材、扩大服务面向、提高服务质量,加强教育沟通,在持续创新中求得自身健康发展。     

浅谈鱼类天然雌核发育

雌核发育是单性鱼类的一种生殖方式,本文简要介绍天然雌核发育鱼类的种类、染色体组成、卵子发生、受精生物学和天然雌核发育的应用。     

昆虫的嗅觉

本文概述了昆虫嗅觉的特点、嗅觉感器的结构和嗅觉的识别作用机理。     

蜱虫简介

本文简要介绍了蜱虫的形态与分布、生活史、生态与习性、传播途径、与疾病的关系、蜱虫叮咬的临床特点、蜱虫引起的传染病的防治原则及最新研究进展。     

实现权力与观念的共筹——对华尔兹与温特体系理论的比较研究

由于体系主要包括单元、结构和进程三个方面,所以文章主要围绕这三个方面对华尔兹的结构现实主义体系理论和温特的建构主义体系理论进行比较分析。通过比较分析可见,二者的理论在解释国际政治的永恒主题——冲突与合作或战争与和平方面,由于偏执于权力或观念的一方而利弊兼有。因此,在解释国家行为及国际政治现象时,应当避免两种理论各自所具有的缺陷,拓宽看问题的视角,实现权力与观念的共筹。     

Development of integrated precision vibration-assisted micro-engraving system

A novel precision vibration-assisted micro-engraving system was developed by the integration of fast tool servo and ultrasonic elliptical vibration system, in which the flexure hinge was designed to avoid backlash and PID control algorithm was established to guarantee specific precision. Apart from experimental validation of the performance of the system, various micro-V-grooves cutting experiments on aluminum alloy, ferrous material and hard cutting material were performed, in which Kistler force sensor was used to measure cutting force. Through experiments, it was clear that the vibration-assisted micro-engraving system can ensure good quality of micro-V-grooves and reduce cutting force by about 60% compared with traditional removal process without ultrasonic vibration.     

Experimental and FEM Study of Coated and Uncoated Tools Used for Dry Milling of Compacted Graphite Cast Iron

Compacted graphite cast iron (CGI) has been the material for high-power diesel engines recently, but its increased strength causes poor machinability. In this study, coated and uncoated carbide tools were used in dry milling experiment and FEM simulation to study the machinability of CGI and wear behaviour of tools. The experimental and FEM simulation results show that coated tool has great advantage in dry milling of CGI. SEM and EDS analysis of tool wear indicate the wear morphology and wear mechanism. Adhesive wear is the main mechanism to cause un-coated tool wear, while abrasive wear and delamination wear are the main mechanism to cause coated tool wear. Stress and temperature distribution in FEM simulation help to understand the wear mechanism including the reason for coating peeled off.