高频串联谐振逆变器频率跟踪控制电路的仿真与应用     

郭红 《宁波职业技术学院学报》2008,12(5):22-26

为了解决高频逆变电源负载参数变化引起固有谐振频率变化,导致逆变器效率降低及开关器件应力增加的问题,提出了一种以集成高速锁相环74HC4046为核心的、应用于功率MOSFET为主开关器件的高频串联谐振逆变电源的无相差频率跟踪控制系统,对电源的输出频率进行实时控制,并用Pspiee进行了仿真分析。结果证明,该系统具有较好的应用前景和推广价值。  相似文献   

审美现代性的吁求———评朱寿兴的《美学的实践、生命与存在》          下载免费PDF全文

王建疆  徐大威 《惠州学院学报》2006,26(5):123-128

朱寿兴的《美学的实践、生命与存在》一书, 努力实现由认识论向存在论的转向, 彰显了中国当代美学界共同的致思取向。该书对中国20 世纪90 年代以来的一些有代表性的美学主张、派别的存在形态作了系统性的审视, 得出了诸多创见。该书所具有的三个特征———立足于本体论的研究视域与回归马克思的美学洞见、对中国当代美学存在形态的整体性研究、体现审美现代性的吁求, 是中国的美学转向所系, 而揭示和阐释这样三个特征也正是中国当代美学形态问题研究的价值所在。  相似文献   

大学生英语听力理解策略的实证调查研究     

常松 《孝感职业技术学院学报》2006,9(4):62-65

文章在秉承听力策略这一领域的研究成果上,通过实证调查方式,发现高分组和低分组学生在策略使用频率上和使用有效性上存在显著性差异,提出教师在听力课上应该进行策略教学.  相似文献   

变频调速在供水系统中的应用     

孙新梅 《淮北职业技术学院学报》2004,3(1):73-74,77

本文介绍了在供水系统中选择变频调速的原因；分析了一种变频调速供水装置的主电路、控制电路、工作原理及应用效果。  相似文献   

基于物联网可交互超市智能购物车设计     

龙正江  刘丽华  林力  李可涵  郜浩  曲宇凯 《辽宁科技学院学报》2019,21(3):17-18

物联网作为信息科学技术的第三次革命,自从2009年“感知中国”以来,受到了全社会极大的关注。文章主要介绍了采用语音识别、RFID射频识别、定位、数据处理等技术开发设计的智能交互购物车,该系统可以很大程度上解决人们在超市的不便,最大化实现了超市的智能化。  相似文献   

反馈环内外电抗元件对频率特性的影响分析     

陈兰莉 《安阳师范学院学报》2005,(5):35-37

通过对两种具有对比效果的电压并联负反馈放大电路的分析,得出影响频率特性的电抗元件包含在反馈环之内时,负反馈能改善由它引起的频率特性,而对反馈环外的电抗元件引起的频率特性,负反馈是无法改善的.  相似文献   

《仓央嘉措情歌》用词特征分析     

董颖红 《云南师范大学学报(哲学社会科学版)》2006,38(5):112-115

本文利用计算机作为分析工具，对流传在藏族地区的第六世达赖喇嘛创作的《仓央嘉措情歌》进行了词频统计和文本搭配索引，并根据计算机的处理结果对《仓央嘉措情歌》的用词特点作出了简要分析。  相似文献   

Exploring the forward citation patterns of patents based on the evolution of technology fields     

Su Jung Jee  Minji Kwon  Jung Moon Ha  So Young Sohn 《Journal of Informetrics》2019,13(4):100985

Forward citations of patents have been used extensively to capture the impact of technological knowledge. However, our understanding of the factors shaping patent citation patterns remains limited. One of the main limitations is the lack of scholarly attention paid to the dynamic influences arising from the evolution of technology fields. From an evolutionary perspective, technological impact is not simply determined by the static attributes of a technology itself; it is also dynamically affected by changes in the external conditions. Drawing on this viewpoint, this study suggests a model for understanding patent citation patterns by reflecting the evolution of the technology fields to which each patent belongs. Four such factors are explored: technology cycle time, potential of technological convergence, popularity of the technology field, and technological novelty. Based on the proposed model, we show how expected citation patterns can change as a result of different scenarios for technology field evolution. We conduct a case study of patents in the information technology and healthcare industries to show citation patterns of patents across heterogeneous industries as well as those within an industry. Contributions to the innovation literature and research investment decisions are discussed.  相似文献   

Challenges of measuring software impact through citations: An examination of the lme4 R package     

Kai Li  Pei-Ying Chen  Erjia Yan 《Journal of Informetrics》2019,13(1):449-461

The rise of software as a research object is mirrored by increasing interests in quantitative studies of scientific software. However, inconsistent citation practices have led most existing studies of this type to base their analysis of software impact on software name mentions, as identified in full-text publications. Despite its limitations, citation data exists in much greater quantities and covers a broader array of scientific fields than full-text data, and thus can support investigations with much wider scope. This paper aims to analyze the extent to which citation data can be used to reconstruct the impact of software. Specifically, we identify the variety of citable objects related to the lme4 R package and examine how the package’s impact is dispersed across these objects. Our results shed light on a little-discussed challenge of using citation data to measure software impact: even within the category of formal citation, the same software object might be cited in different forms. We consider the implications of this challenge and propose a method to reconstruct the impact of lme4 through its citations nonetheless.  相似文献   

多媒体环境下的高频电子线路课堂教学探讨     

王岳  刘纯利  张平娟 《教育教学论坛》2019,(28):265-266

高频电子线路是电子与通信技术专业的一门重要的专业基础课程,同时也是一门理论性、实际性、专业性、实践性很强的课程。随着科学技术的发展,多媒体技术开始逐渐进入高频电子线路课堂教学,极大促进了高频电子线路课堂教学的发展。文章对多媒体环境下高频电子线路课堂教学进行探讨。  相似文献