基于单片机应用系统的电磁兼容性分析

本文是在基于红外成像技术的电力设备状态检测系统中,解决系统的电磁兼容性问题,增强系统的抗干扰能力和工作的安全性。文中先从原理入手分析单片机应用系统电磁兼容性,然后,阐述了单片机应用系统设计技术,分析了原理图及印刷板(PCB)的设计规则,使系统提高抗辐射干扰和抗传导干扰的能力。     

射频电路中降低电磁辐射的思索

本文分析了不同应用目的和背景下设备对接地设计的要求,并通过实例阐述了接地技术在高速电路设计中的应用。射频电路PCB设计的关键在于如何减少辐射能力以及如何提高抗干扰能力,只有通过优化电路板的层间距设计以及布局布线或者其他的降低电源、地噪声的方法等来解决电源完整性问题,同时抑制EMC／EMI。     

三明治沟通法在全英文探究式教学中的应用

探究式教学能够加强学生的自主性,促使学生建立自己的认知模型和学习方法架构,因此,近年来获得了越来越多的关注。随着高等教育国际化的不断发展,全英文教学在中国已经成为重要发展方向,如何利用英文进行有效沟通,对于探究式课程教学效果至关重要。本文详细介绍了三明治沟通法,并将其在全英文探究式教学中进行了应用。主观和客观效果评价表明,三明治沟通法在全英文探究式教学中能够有效激发和维持学生的学习热情,有益于教学质量的提升,其应用值得推广。     

混沌调制对改善直流变换器电磁兼容性的研究及仿真

混沌信号具有类随机、连续频谱的特性,混沌调制用于直流开关变换器可以扩展频谱,抑制电磁干扰（EMI）。但实际产生的混沌信号频谱具有一定的范围,如由蔡氏电路产生的模拟混沌信号,具有一个特殊频率并以之为中心左右基本对称的频谱范围,这个频率为中心频率并由电路的实际参数所决定。本文以BUCK变换器为例,采用外接蔡氏电路作为模拟混沌信号发生器,分别选用合适中心频率的混沌信号,实施混沌化占空比和混沌化频率的方案,通过计算机仿真结果进行对比,验证了混沌调制具有改善电磁兼容（EMC）的性能,且混沌化频率的方案抑制EMI效果更明显。     

Learner Resistance to English-medium instruction practices: a qualitative case study

The internationalization of higher education has resulted in the growth of English-medium instruction (EMI) practices and research. The existing EMI research has documented learners’ favorable attitudes toward EMI but not necessarily its practices. Learners’ dissatisfaction has not been viewed as a form of resistance. Through the notion of learner resistance that underscores agency in defiance, this study examined the occurrences of learner resistance and the reasons for it by investigating Chinese learners’ experiences in an undergraduate business English-taught program in Taiwan. Multiple sources of data, including interviews, stories, and class observations, were gathered for analysis. The findings showed that most Chinese learners resisted an unhelpful curriculum, pedagogy, and context. Their resistance may be related not simply to academic disciplines but more importantly to a Confucian Heritage Culture of learning. Such findings highlight learner agency in resisting actions and call for further investigation into potential learner resistance in EMI practices.     

基于FPGA的高速PCB的设计

采用高速FPGA进行PCB板设计中,既需要兼顾信号完整性,保证信号质量,又需要针对EMI干扰,按照减小电磁干扰的要求进行设计,为I/O接口提供良好的ESD保护,降低电路设计复杂度,节约设备成本。文章针对以上设计要求,研究了电源分布、传输线和信号走线、阻抗匹配、串扰、EMI等问题的设计技术。     

English as a medium of instruction at a Chilean engineering school: Experiences in finance and industrial organization courses

Implementing English as a medium of instruction (EMI) in Latin American countries contributes to reducing language exchange isolation in the region and helps prepare higher education students for future labor opportunities. However, one of the main concerns around EMI is whether English instruction could negatively affect content acquisition. This paper examines if the performance of native Spanish speakers is affected by EMI. Specifically, it discusses experiences from finance and industrial organization courses given to industrial engineers at a Chilean university. The results of a multivariate analysis of tests and final grades show that performance differences can mainly be attributed to students’ performance in previous courses; only on rare occasions do language, gender, and attendance explain performance differences.     

软开关脉宽调制变频技术

In this paper, a new soft-switching inverter using a minimum number of devices, and a new PWM (pulse-width modulation) method suitable for 3-phase soft-switching inverters are proposed. The circuit is used as an interface between the DC supply and the conventional voltage source of a PWM inverter. The number of switching operations can be reduced by using the PWM strategy. Increasing the amplitude of the fundamental component contained in the output waveform results in an effective utilization of the DC supply, a reduction of nominated capacity of the inverter elements, and a reduction of switching loss in the switching devices. Supported by National Natural Science Foundation of China (59977012)     

医学院校体育教师对EIM理念运动处方教学的认知现状研究——以安徽省4所医学院校为例

运用文献法、问卷法、访谈法、数理统计法等,对安徽省医学院校体育教师对EIM理念运动处方教学的认知现状进行调查,同时对安徽省医学院校开展EIM理念运动处方教学的影响因素进行分析研究,以期促进安徽省医学院校体育教育改革,深化EIM理念体育教学策略对医学生培养规格影响的探讨.     

Study of the effectiveness of anti-phase technique for common mode noise suppression

This paper discusses the properties of a novel boost converter with auxiliary anti-phase winding approach resulting in low conducted common code noise level. A simplified equivalent circuit of the proposed boost converter is modeled to analyze its performance and to show the influence of the parasitic winding capacitance, as well as the stray capacitances of the switching waveform nodes into the earth plane. Simulation and experimental results are shown to verify the concept. Project supported by NSFC (50077020) Ph.D student of Zhejiang University, from Morocco.