现代电源技术实验平台研制

为构建完整的电力电子技术中使用各种电力电子器件进行功率变换的知识体系,研制了现代电源技术综合实验平台,其包括单端隔离型高频开关电源实验、隔离型桥式DC/DC实验和变频调速实验3个实验。对3个实验的核心控制电路进行了详细介绍,并给出对应的工作波形。该实验平台可满足电气工程高年级本科生、研究生实验的要求,同时也可给相关教师提供功率变换的科研平台。     

Dimensions of Socio-economic Status and their Relationship to Mathematics and Science Achievement at Individual and Collective Levels

Applying two-level structural equation modelling techniques, the current study examined the dimensionality of socio-economic status (SES) and its relationship with mathematics and science performance at student and school levels. Data were drawn from population 2 (13-year-olds) of 17 countries in the Third International Mathematics and Science study (TIMSS). A set of items about the ownership of household materials was used to measure the dimensions of SES. For most of the countries, a general economic dimension and a cultural dimension were identified at the student level. The cultural dimension had the greatest impact on students' mathematics and science achievement. At the school level, however, only a general economic dimension was found in most countries. This dimension was interpreted to represent community wealth. It was found to be highly related to school mean maths-science achievement, except for the countries where an additional cultural dimension is identified. This cultural dimension can be interpreted as the community cultural resources and atmosphere, and is strongly related to average school mathematics and science achievement. The current study confirmed that the ownership of a set of household materials can be used as SES indicators in exploring its multifaceted feature at both individual and school levels. A similar model structure is found in different countries by applying these indicators, despite the fact that the content of the set of household possessions is different. The findings show that the latent structure of SES at individual level is different from that at the school level, and that SES dimensions have different effects on mathematics and science achievement at individual and school levels.     

统计/判决电路在通信电子实验教学中的应用

鉴于通信电子技术课程的教学现状,提出了依据统计/判决电路来设计通信电子实验,在8分频的前提下,该电路可以在改进系统通信质量方面起到一定的作用,如改善信噪比,降低误码率,提高系统抗干扰性。通过对该电路的设计、制作和调试,学生能掌握诸如香农公式、数字信号最佳接收等理论知识。能较好实现培养理论和实际动手能力相结合的教学要求。     

Advanced Math Course Taking: Effects on Math Achievement and College Enrollment

Using data from the Educational Longitudinal Study of 2002–2006, the authors investigated the effects of advanced math course taking on math achievement and college enrollment and how such effects varied by socioeconomic status and race/ethnicity. Results from propensity score matching and sensitivity analyses showed that advanced math course taking had positive effects on math achievement and college enrollment. Results also demonstrated that the effect of advanced math course taking on math achievement was greater for low socioeconomic status students than for high socioeconomic status students, but smaller for Black students than for White students. No interaction effects were found for college enrollment. Limitations, policy implications, and future research directions are discussed.     

幂等的Hemite矩阵与矩阵的分解

研究了任意矩阵的分解与幂等的Hemite矩阵的一些内在的关系。     

基于网络的教务管理系统的设计与实现

基于网络的教务教学管理是21世纪教务教学管理的发展方向.采用B/S结构的开发模式,可安全、有效地对网络化教务教学管理信息系统进行设计和实现.实践证明,它能够方便地协调好教师、学生、教室三者的关系,使资源达到最大化的利用.     

Gender and IT in the Household: Evolving Patterns of Internet Use in the United States

Information technology (IT)—computers and related technologies—is the latest technology to enter the household. Like other technologies, gender is a major factor in its adoption and use as well as its perceived usefulness. Unlike prior household technologies, the computer's entry into the household has followed a different pattern. Early statistics revealed a vast gender divide, with men using computers and related technologies much more in the household. More recent statistics show a narrowing of the divide, perhaps even a reversal, particularly in the United States, with women outnumbering men in the access to and use of the Internet. In this article, the role of gender and its relationship with Internet use in the home are reviewed. In addition to overall adoption and access, the review focuses on specific Internet applications and examines the factors that contribute to gender differences in adoption and use of computers and Internet applications in the home.     

中学全员参与式心理健康教育模式初探

该文在探讨以往学校心理健康教育模式的基础上,提出了“1-3-3”(一支队伍、三条途径、三个目标)的全员参与式心理健康教育模式。倡导成立心理健康教育领导组织与实施队伍,通过“五个一”氛围营造、对系统中人员的分层分类培养与培训以及线上线下相结合的途径,实现心理健康教育发展、预防与指导的目标,让与学生心理发展有关的人——学生、教师、后勤人员、家长都参与其中,每个人都参与、都受益,能自助、会求助,部分人员能助人。     

Accidental digitoxin intoxication: an interplay between laboratory and clinical medicine

Introduction:

Two Italian adults arrived at the Emergency Department referring diarrhea, nausea and vomiting for 4 days; weakness, fatigue and visual hallucinations were also complained of. Patients reported the ingestion of some leaves of a plant, which they supposed to be “donkey ears”, a week before. Physical examination showed hypotension and bradycardia and ECG examination disclosed sinus rhythm and repolarization abnormalities (scooping of the ST-T complex) in both patients and a 2:1 AV block in the man.

Materials and methods:

Digoxin concentration was evaluated twice for each patient (at the admission and after 4 hours) by the automated immunoassay system ADVIA Centaur^®. Digitoxin concentration was evaluated by liquid chromatography-mass spectrometry (LC-MS/MS).

Results:

Despite clinical picture was suggestive of digitalis intoxication, digoxin levels were undetectable. Due to the more severe clinical picture, the male patient was treated with anti-digoxin antibodies (Digifab^®) achieving a good clinical improvement and remission of the AV block within two hours. Initial diagnosis was confirmed by LC-MS/MS showing high digitoxin concentrations, but digoxin was undetectable. Patients remained stable and 48 hours later were discharged from the hospital.

Conclusion:

Whereas digoxin determination frequently relies on monoclonal antibodies which do not cross-react to digitoxin, polyclonal antibodies constituting Digifab^® recognize a large spectrum of cardiac glycosides, including digitoxin. This report emphasizes the primary role of the clinical approach to patients in the emergency setting and how an active communication and a continuous sharing of professional experiences between Laboratory and Clinicians ensure an early and correct diagnosis.     

基于多主体协同创新的产学研联盟运行机制研究※(修改）

加强产学研融合和提出具有可行性的产学研联盟运行机制具有重要意义,笔者针对目前产学研联盟在运行过程中存在的诸多不协调的原因进行了分析,提出了多主体协调创新的产学研联盟运行机制,通过建立保障制度、人才软引进、健全工作机制和协调盈利模式等实现多方利益共赢,尤其是倡导利用商业化运营公司解决目前产学研联盟中的一些运行弊端来促进产学研联盟的健康发展。研究成果把运行机制具体化,并经过了实践的检验,便于落实和推广。