高校机电类课程网络化仪器的设计与教学实践

本文介绍了高校实施网络化仪器与教学的现状,阐述了实施网络化仪器与教学的必要性和可行性,并以机电类课程为例,分析了实施网络化仪器与教学的具体措施,希望藉此将网络化仪器与教学的研究引向深入。     

中学教师教学反思现状的调查分析与研究

教学反思有助于形成教师的实践性知识,是促进教师专业发展的有效策略。通过调查研究对当前学校教师教学反思的现状进行了分析,包括教师当前教学反思的概况、教师对反思的认知、反思的动因及影响反思的因素等,在此基础上从教师专业发展的角度提出了有效促进教师教学反思的若干建议。     

能力培养视角下分析化学实验教学改革

根据分析化学实验课的教学现状和存在问题,提出从实验教学内容、教学模式和方法及实验考核等方面进行改革,提高学生学习的主动性,强化学生创新能力和实验动手能力的培养。     

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter. The coupling coils and human tissues, including the skin, fat, muscle, liver, and blood, were considered. Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model. First, SAR and current density as a function of frequency (10–10⁷ Hz) for an emission current of 1.5 A were calculated under different tissue thickness. Then relations between SAR, current density, and five types of tissues under each frequency were deduced. As a result, both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The results show that the analysis of these data is very important for developing the artificial anal sphincter system.     

Transgenic barley with overexpressed PTrx increases aluminum resistance in roots during germination

A transgenic barley line (LSY-11-1-1) with overexpressed Phalaris coerulescens thioredoxin gene (PTrx) was employed to measure the growth, protein oxidation, cell viability, and antioxidase activity in barley roots during germination on the presence of 2 mmol/L AlCl₃ on filter paper. The results show that (1) compared with the non-transgenic barley, LSY-11-1-1 had enhanced root growth, although both were seriously inhibited after AlCl₃ treatment; (2) the degree of protein oxidation and loss of cell viability in roots of LSY-11-1-1 were much less than those in roots of non-transgenic barley, as reflected by lower contents of protein carbonyl and Evans blue uptakes in LSY-11-1-1; (3) activities of catalase (CAT), glutathione peroxidase (GPX), ascorbate peroxidase (APX), and glutathione reductase (GR) in LSY-11-1-1 root tips were generally higher than those in non-transgenic barley root tips, although these antioxidase activities gave a rise to different degrees in both LSY-11-1-1 and non-transgenic barley under aluminum stress. These results indicate that overexpressing PTrx could efficiently protect barley roots from oxidative injury by increasing antioxidase activity, thereby quenching ROS caused by AlCl₃ during germination. These properties raise the possibility that transgenic barley with overexpressed PTrx may be used to reduce the aluminum toxicity in acid soils.     

20世纪90年代后期NBA传奇后卫进攻技术特点的分析与比较

运用文献资料法、数理统计法等研究方法对20世纪90年代后期NBA传奇后卫进攻技术特点进行分析比较,结果表明：NBA传奇后卫虽然类型特点各不相同,但他们都是篮球赛场上的核心领导者,具备良好的身体素质,娴熟的球技,清醒的头脑,宽广的视野,必胜的信心,多种多样的攻击方式和极强的组织领导能力．     

Analysis of a rainwater harvesting system for domestic water supply in Zhoushan, China

The domestic rainwater harvesting system （DRHS） is an water demands. A computer model has been generated to analyze the important freshwater source for Zhoushan, China to meet performance of the DRHS with different ratios of D/（AR） （water demand/average annual collected runoff） and S/（AR） （storage capacity/average annual collected runoff）. The performance of the DRHS was analyzed by means of the model simulation, which is described by its water shortage rate （WSR） and water loss rate （WLR）. Using the data, a set of dimensionless design calculation chart is introduced. When the water demand and requirement of the design are known, the established chart can be used to easily determine the storage capacity and catchment （roof and other surface） area required to achieve a desired performance level.     

Numerical computations of the flow in a finite diverging channel

The flow in a finite diverging channel opening into a large space and resembling the experimental prototype of Putkaradze and Vorobieff （2006） was numerically investigated. The effects of the Reynolds number, initial condition, intersection angle, length of the wedge edges, and the outer boundary condition were examined. The numerical results showed that the flow in the wedge undergoes a change from symmetrical flow to unsymmetrical flow with a weak backflow, then a vortical （circulation） flow and finally an unsteady jet flow as the Reynolds number is increased for an intersection angle of 32° and a wedge edge of length 30 times the width of the inlet slit. For the unsteady flow, the jet attached to one side of the wedge constantly loses stability and rolls up into a mushroom-shaped vortex-pair near the outlet of the wedge. As the intersection angle is increased to 50°, a stable jet flow is observed as a new regime between the vortex and unsteady regimes. Both the intersection angle and the wedge length have negative effects on the stability of the flow, although the effect of the wedge length on the critical Reynolds number for the symmetry-breaking instability is not pronounced. The outer boundary condition was found not to affect the flow patterns inside the wedge significantly. At a certain Re regime above the onset of symmetry-breaking instability, the flows evolve into steady state very slowly except for the initial stage in the case of decreasing flow flux. Two different solutions can be observed within the normal observation time for the experiment, providing a possible explanation for the hysteresis phenomenon in the experiment.     

学科服务互动合作的理念探析与实践进展

学科馆员制度引入中国图书馆界多年,现迫切需要寻找工作的突破点。清华大学图书馆提出互动式、合作化的学科服务理念,强调学科服务的双向互动性,把读者的参与和组织机构之间的合作纳入到学科服务范畴之中。图书馆与学科馆员的单边力量有限,互动式、合作化将是学科服务深化的必然要求,也是学科服务理论的重要发展。     

汶川地震信息资料库元数据规范编制

距离汶川地震已有两年时间,灾后重建工作已经取得了一定的成效。对于档案部门来说,保存汶川地震相关资料对于今后的工作查考、历史研究以及经验借鉴等方面具有重要的意义。国务院颁布的《汶川地震灾后恢复重建条例》明确规定:地震部门、地震监测台网应当收集、保存地震前、地震中、地震后的所有资料和信息,并建立完整的档案。国家档案局就汶川地震文件归档工作专门下发了《国家档案局关于做好抗震救灾工作文件材料收集归档工作的通知》。中国地震局根据相关文件要求开展了汶川地震信息资料库的建设,并借鉴国际上的先进思想,以多实体模型为基础,编制了一整套汶川地震信息资料库元数据规范,以确保库中数据的真实性、完整性与长期可读性,为今后的利用工作打下坚实基础。