Erosion behavior and mechanism of boronised steels     

刘立  凌国平  刘涛  郦剑 《浙江大学学报(A卷英文版)》2002,3(3):278-282

Boronising of steels is a hardening process to get high surface hardness. The erosion resistance of boronised steels was researched with the use of four kinds of erodent, i.e. glass, alumina, quartz and silicon carbide. The erosion rate increases rapidly with erodent hardness and severe erosion occurs with high impacting angle range of hard particles. SEM analysis indicated that chipping is caused by repetitive impacting of glass and quartz, whereas by alumina and silicon carbide impacting, chipping, and that plastic flow take place simultaneously and the erosion rate reaches the peak value when the impacting angle is above 60°.  相似文献   

塞拉斯的科学实在论本体观     

张能为 《安庆师范学院学报(社会科学版)》2001,20(3):80-84

科学实在论是现代科学主义重建形而上学的一种新形态。塞拉斯肯定科学影像优先 ,建立理论实体存在观 ,从科学理论角度重新讨论了人类认识的基础 ,充且肯定了形而上学因素特别是本体论在科学理论中的重大作用。  相似文献   

DNA damage response is hijacked by human papillomaviruses to complete their life cycle     

Shi-yuan Hong 《Journal of Zhejiang University. Science. B》2017,18(3):215-232

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20世纪后半期局部战争的特点及类型剖析     

张俊杰 《桂林师范高等专科学校学报》2005,19(4):38-42

从二次世界大战结束到现在，局部战争连绵不断。局部战争制造并加剧了国际局势的紧张，威胁着世界的和平与安全，是世界不安宁的主要因素。探讨局部战争的根源和起因，剖析局部战争的特点和类型，制定正确的政策和策略，对于维护世界持久和平、保障各国人民的自由、独立和社会进步，具有重大现实意义。  相似文献   

在局域网上组建视听网络课室     

张庆有 《中国电化教育》2002,(8)

所谓视听网络课室就是运用网络功能实现视频、音频点播并且具有交互功能及数据库处理的网络。也就是说，组建视听网络课室必须考虑的问题有：（１）硬件环境；（２）软件环境；（３）相应的课件。一、硬件环境硬件环境要达到实现视频、音频点播，就必须要有宽带高速的网络基础。要达到高速，就要解决服务器的吞吐量和网路的带宽。采用分布网络系统，即视频服务器、web服务器、数据服务器分开，由高速交换机或高速路由连接。下面是我校视听网络课室的网络连接图：由图可见，我们采用了三台视频服务器，每台视频服务器供５０个用户，整间课室…  相似文献   

Two ancient rounds of polyploidy in rice genome   总被引：10，自引：0，他引：10  

Zhang Y  Xu GH  Guo XY  Fan LJ 《Journal of Zhejiang University. Science. B》2005,6(2):87-90

An ancient genome duplication (PPP1) that predates divergence ofthe cereals has recently been recognized. We report here another potentially older large-scale duplication (PPP2) event that predates monocot-dicot divergence in the genome of rice(Oryza saliva L.), as inferred from the age distribution of pairs of duplicate genes based on recent genome data for rice. Our results suggest that paleopolyploidy was widespread and played an important role in the evolution of rice.  相似文献   

努力打造东北老工业基地职业教育与培训的旗舰     

于晓旭  张志刚 《继续教育研究》2004,(3):50-52

人才是振兴东北老工业基地的决定性因素，大力发展职业教育和以职工技能培训为主的继续教育，事关老工业基地振兴战略全局，是全面提高劳动者素质，发展先进生产力的必然要求，是进行人力资源开发，推动经济社会可持续发展，提高企业核心竞争力的重要途径，是促进劳动就业，维护社会稳定的重要举措。  相似文献   

汉语言远端教育文化圈:一个值得注意的远端教育文化构想     

张亚斌  王淑娟 《现代远程教育研究》2005,(1):43-47

“汉语言远端教育文化圈”概念是一个基于“文化圈”理论的现实构想，其目的是利用现代信息技术和教育技术，使全球范围内每一个运用汉语言媒介进行远程学习的人，都能满足其接受高等教育的梦想。本文基于对“汉语言远端教育文化圈”两大结构层次：以汉语为母语的“华裔社会人群远端教育文化圈”和以汉语作为文化交流语言或对汉语有着深厚思想感情的非华裔人群的“非华裔社会人群远端教育文化圈”的文化背景，结构及其思想体系的剖析，对于“汉语言远端教育文化圈”内外的多种远端教育圈合作，尤其是远端教学资源建设的开发与共享合作，提出了极具建设性的构想和意见。  相似文献   

Games for boys: a qualitative study of experiences with commercial off the shelf gaming     

Jason A. Engerman  Monique MacAllan  Alison A. Carr-Chellman 《Educational technology research and development : ETR & D》2018,66(2):313-339

Boys are less likely to receive praise and recognition for good schoolwork, to consider school important, and have fewer opportunities to do the things that they do best (Lopez and Calderon in How America’s boys become psychological dropouts. The gallup blog, 2013). Traditional school cultures have come in conflict with the normal and natural ways that boys behave. As a result, boys have had alienating experiences and high levels of disengagement and lowered academic success in school due to rejection of boy culture, which includes aggressive play, competition, and violent fantasy. The purpose of this study was to explore ways in which we can re-engage boys and enhance their learning opportunities in traditional classroom settings. Boys are drawn to video games, which offer a unique environment where they can engage in learning activities. By taking seriously the indigenous knowledge of this portion of boy culture, we may identify ways in which their expertise can become useful towards common learning goals (Carr-Chellman 2007; Carr-Chellman and Savoy 2004). The current analysis represents the first of a multiphase study that uses an interpretive lens within a CHAT framework to identify relevant learning in Commercial of the Shelf (COTS) games. This phenomenological design identifies learning accounts that map to the United States Common Core State Standards. Our findings suggest that engaged learning can occur for these boys as a result of playing games. COTS games engage boys in normal and natural ways, and consequently can be relevant learning tools that educators, researchers and instructional designers might employ toward traditional learning objectives.  相似文献   

浅议我国高等教育改革发展的几种趋势     

张福生 《现代教育科学》2001,(2):6-8

国务院批准的“教育部 2 1世纪教育振兴行动计划”明确提出 :至 2 0 10年要把我国的高等教育毛入学率由原来的 8%左右 ,提高到 15 %。根据我国经济发展的实际需要 ,这一发展目标还有可能被提前。在短短的 10年间 ,要使我国高等教育规模翻一番 ,实现由精英型阶段向大众化阶段的历史性转变 ,高等教育改革就必须有所突破。笔者认为 ,根据我国高等教育发展的客观需要 ,高等教育将面临以下几方面改革。　　一、高等教育文凭制度向学校文凭制度转变我国目前实行的高等教育学业证书制度具有明显的国家色彩。具体表现为 :国家教育行政部门对高等学校…  相似文献