A NEW MODEL FOR ELECTRON BEAM GENERATED BY SOFT VACUUM DISCHARGE

ＡＮＥＷＭＯＤＥＬＦＯＲＥＬＥＣＴＲＯＮＢＥＡＭＧＥＮＥＲＡＴＥＤＢＹＳＯＦＴＶＡＣＵＵＭＤＩＳＣＨＡＲＧＥＬｕｏＺｈｏｎｇｎａｎ（罗宗南）；ＣｕｉＹｉｐｉｎｇ（崔一平）；ＣｈｅｎＳｏｎｇｓｈｅｎｇ（陈松生）；ＹａｎｇＺｈｅｎｇｍｉｎｇ（杨正名）（Ｄ...     

A MODIFIED CRANK－NICOLSON SCHEME FOR THE INITIAL－BOUNDARY VALUE PROBLEM OF SUPERTHERMAL ELECTRON TRANSPORT EQUATION

ＡＭＯＤＩＦＩＥＤＣＲＡＮＫ－ＮＩＣＯＬＳＯＮＳＣＨＥＭＥＦＯＲＴＨＥＩＮＩＴＩＡＬ－ＢＯＵＮＤＡＲＹＶＡＬＵＥＰＲＯＢＬＥＭＯＦＳＵＰＥＲＴＨＥＲＭＡＬＥＬＥＣＴＲＯＮＴＲＡＮＳＰＯＲＴＥＱＵＡＴＩＯＮＳｕｎＺｈｉｚｈｏｎｇ（孙志忠）（Ｄｅｐａｒｔ...     

A STUDY ON THE ECONOMIC BENEFITS IN DEVELOPMENT OF FRESHWATER FARMING

ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅ 1 978,Ｃｈｉｎａ’ｓｆｉｓｈｅｒｙｉｎｄｕｓｔｒｙｈａｓｗｉｔｎｅｓｓｅｄａｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔａｎｄａｎｎｕａｌｇｒｏｗｔｈｏｆ 1 2 %ｒｉｓｅ .Ｔｈｅｏｕｔｐｕｔｏｆａｑｕａｔｉｃｐｒｏｄｕｃｔｓｈａｓｂｅｅｎｔｏｐｒａｎｋｉｎｇｉｎｔｈｅｗｏｒｌｄｆｏｒ 1 2ｒｕｎｎｉｎｇｙｅａｒｓｓｉｎｃｅ 1 988ｗｈｅｎＣｈｉｎａｓｕｒｐａｓｓｅｄＪａｐａｎｉｎ1 998.Ｌａｓｔｙｅａｒ’ｓｏｕｔｐｕｔａｍｏｕｎｔｅｄｔｏ 4 1ｍｉｌｌｉｏｎｔｏｎｓ(Ｎａｔｉｏｎａｌ…     

PROBABILISTIC ANALYSIS AND MONTE CARLO SIMULATION OF THE KINEMATIC ERROR IN A SPATIAL LINKAGE

The stochastic models of the usual joints are first established through intro-ducing the concepts of“clearance characteristic element”and“clearance space”.After de-riving the probability density function of the joint clearance and making the probabilisticanalysis of the resulted kinematic errors,the sampling formulas of the independent varia-bles of the joint clearances are further deduced.Through Monte Carlo simulation,the sta-tistical characteristics and frequency histograms of the kinematic errors are then analysedon computer.     

A MINI－CAPACITANCE PROBE FOR MEASURING THE LOCAL VOID FRACTION IN GAS－SOLID FLUIDIZED BEDS

ＡＭＩＮＩ－ＣＡＰＡＣＩＴＡＮＣＥＰＲＯＢＥＦＯＲＭＥＡＳＵＲＩＮＧＴＨＥＬＯＣＡＬＶＯＩＤＦＲＡＣＴＩＯＮＩＮＧＡＳ－ＳＯＬＩＤＦＬＵＩＤＩＺＥＤＢＥＤＳＧｕｉＫｅｔｉｎｇ（归柯庭）ＨａｎＪｉｔｉａｎ（韩吉田）ＳｈｉＭｉｎｇｈｅｎｇ（施明恒）（Ｄｅ...     

FEASIBILITY STUDY FOR A JOINT COUNCIL OF EUROPE/UNESCO CONVENTION ON ACADEMIC RECOGNITION FOR THE EUROPE REGION∗

This feasibility study considers, from a number of angles, the adoption of a joint Council of Europe/UNESCO Convention on Academic Recognition stressing in particular its educational advantages. Among the issues to be addressed by a joint convention are the questions of definitions, the length and content of studies, entrance examinations, nontraditional qualifications, the problems of refugee students, international qualifications, numerus dausus, intermediate and final higher education qualifications, and the assessment and accreditation of higher education institutions. The two Secretariats have concluded that a joint convention is desirable, timely, and feasible, and that this feasibility study, including the recommendations of the ad hoc expert group, constitutes the basis for the elaboration of such a convention.

     

FIRST YEAR IMPLEMENTATION OF A PROJECT-BASED LEARNING APPROACH: THE NEED FOR ADDRESSING TEACHERS�� ORIENTATIONS IN THE ERA OF REFORM

The purpose of this study was to examine the extent to which three teachers’ professional experience and existing orientations toward teaching and learning mathematics and science influenced their implementation of a project-based curriculum (i.e. project-based learning (PBL)). Data sources included interviews, videotapes of classroom activity, and a teaching philosophy questionnaire. Data analysis was conducted using an iterative coding technique. We found coherency between the teachers’ perceived orientations and their emergent ideas about PBL, their sense of PBL as being compatible with their goals, and the specific challenges with which they struggled. All the teachers wanted their students to be successful; however, different definitions of success led to quite different approaches toward teaching, and for the most part, these differences appeared to have occurred because of existing orientations the teachers held for teaching their discipline. Implications for professional development taking into account teachers’ orientations and thus their professional experience are discussed, as well as disciplinary challenges to using PBL.     

INDIGENOUS STUDENTS’ EXPERIENCES OF THE HIDDEN CURRICULUM IN SCIENCE EDUCATION: A CROSS-NATIONAL STUDY IN NEW ZEALAND AND TAIWAN

The tacit messages transmitted to indigenous learners in the science classroom provide a lens through which indigenous disengagement with school science can be better understood. In this paper, the findings of a cross-national comparative study conducted with indigenous Maori students in New Zealand and Seediq/Atayal students in Taiwan are discussed from a sociological perspective. The purposes of the present study were to explore the ways in which indigenous elementary school students in two industrialized nations experience the science curriculum and to identify the socialization processes through which patterns of indigenous under-achievement in science are maintained and reproduced. The findings suggest that the peripheral positioning of indigenous culture and knowledge within the science curriculum in developed nations underpins a series of tacit pedagogical codes that contribute to indigenous student disengagement with the subject.     

STUDENTS’ SOURCES OF MOTIVATION FOR PARTICIPATING IN SCIENCE FAIRS: AN EXPLORATORY STUDY WITHIN THE CANADA-WIDE SCIENCE FAIR 2008

Science fairs have been for many years a popular school activity in North America. They are a venue for the popularization of science and consequently an important encouragement for the pursuit of careers in science or engineering. However, little is known about students?? perceived motives for participating in local or national science fairs and about the way in which their involvement mediates their interest in science learning and scientific careers. The present study investigates the motivational factors associated with the high school students?? decision to participate in the 2008 Canada-Wide Science Fair, a thoroughly selected and highly motivated group. Our study examines 5 sources of motivation: (1) interest in science content, (2) sense of self-efficacy, (3) assurance of achievement through rewards or gratifications, (4) the social aspect of participating and (5) working strategies to gain scientific knowledge and methods. The understanding of the anticipated benefits participants seek through their involvement in science fairs may have the potential to help science teachers adapt instruction to appeal to a broader range of students in schools, thus nourishing the emergence of more interest in science.     

一种新型摆动器自由电子激光的自发辐射谱

利用广义Bessel函数计算出了ShlomoPinhas提出的磁场与纵向坐标无关的摆动器的自发辐射谱，并对结果进行了分析。     

电工实验中的测量误差分析及消除方法

本文讨论电工实验中常见的几种误差来源，对实验中出现的误差进行分析，提出几种消除电工测量误差的测试技术。     

波浪作用下海底软粘土的离心模型试验研究(英文)

研究了采用离心模型试验来研究波浪与土相互作用的方法,并针对渤海某油田的波浪及土质条件进行了试验研究.结果表明,在最大波高作用下,软粘土层的上部发生了软化,但这种影响随着深度的增加而逐渐减小;在波浪荷载的作用下,软粘土层下的粉砂层没有液化迹象.     

在非惯性质心参考系中的能量规律

提出非惯性质心系之概念,推导出非惯性质心系中质点组动能定理、功能原理、机械能守恒定律。     

霍尔效应法测磁场的误差来源及消除分析

分析了霍耳效应法测磁场的误差来源，提出了为减少误差应采取的措施及注意事项．     

电子在长直载流导线磁场中运动的自发辐射

根据电子在长直载流导线磁场中的运动和相对论性电子产生辐射的一般规律，计算并分析了电子在这种磁场中运动所产生的自发辐射强度分布，最后的结果中包含一个重要因子sin2η，正是它把自由电子的自发辐射与受激辐射联系起来了。     

汽车生产过程中能源消耗的碳排放计算与分析

在对汽车生产过程四大工艺进行描述的基础上,对汽车生产过程能源消耗碳排放源进行分析;然后分别建立汽车生产过程的四大工艺和物料移动能源消耗的碳排放计算模型;最后以某汽车生产企业为例,对其生产过程碳排放量进行计算,并对碳排放计算结果进行分析。     

基于压电悬臂梁的振动能量获取装置的建模及数值仿真

振动能是自然环境中广泛存在的一种能量,振动式发电机可将其提取并转换为可直接利用的电能。设计了一种用于收集环境中低频振动能的三质量块压电悬臂梁装置,利用压电薄膜的正压电效应将机械能转化成电能。建立悬臂梁的数学模型,用ANSYS软件建立悬臂梁的仿真模型,然后对其进行模态分析,耦合分析,谐响应分析并绘制出压电振子的频率-电压曲线图。研究结果表明该悬臂梁产生的电压可以满足无线传感器节点的使用要求,且优于单质量块悬臂梁。     

U形压强计测量流体输送管某两点压强差教学浅见

本文从U形管压强计测量流体输送管某两点压强差,具有普遍性计算式的推导,找出设备压强定量描述式,从而得出真空度、表压两个基本概念及其与绝对压强的相互关系,避免常见化工教材仅用语言描述的弊端。