416 research outputs found

    Research on Bridge Modular Switched-Capacitor AC-AC Converter and Control Strategy

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    在需要对交流电进行升降压的场合,AC-AC功率变换器相比传统自耦变压器具有体积小、重量轻等优点。开关电容功率变换器由于不含磁性元件,能够显著提高变换器效率、减小体积。本文首先提出了一种桥式模块化双向开关电容AC-AC变换器,能实现变比为4n或1/4n(n=1,2,3…)倍的AC-AC变换。阐述了该变换器的拓扑结构、工作原理及基本性能。设计并研制了一台实验样机,额定功率600W,电压220V/55Vrms,开关频率100kHz。 然后,针对传统开关电容变换器输出电压不可调节问题,提出了一种相控谐振型开关电容AC-AC变换器,由桥式模块化双向开关电容AC-AC变换器和小型谐振电感组成。由于电感的...With the requirement of step-up/step-down AC voltage from those available on the electrical grid, the AC-AC power converters has smaller size and lighter weight than the conventional autotransformer. Because of without magnetic devices, switched-capacitor power converters can achieve significant size reduction and high efficiency in comparison with the converters generally used in conventional swi...学位:工学硕士院系专业:航空航天学院_精密仪器及机械学号:1992013115290

    Vowels production by Cantonese-speaking children with cochlear implant

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    "A dissertation submitted in partial fulfillment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, 30th June, 2010."Includes bibliographical references (p. 28-32).Thesis (B.Sc)--University of Hong Kong, 2010.This study investigated vowels production by Cantonese-speaking children with cochlear implant. Nineteen subjects with cochlear implant age ranged 2;05 to 6;01 years old were compared to 19 hearing children. All participants were required to produce 51 words, covering seven Cantonese monophthongs /a, i, E, O, u, y, J/ and ten Cantonese diphthongs /ui, Oi, ai, iu, Ey, Ai, ou, ei, au, Au/. The production accuracy was compared. Error patterns were investigated by phonological process and acoustic analysis. The production accuracy from cochlear implant subjects with hearing experience less than two years was significantly different than that of hearing children with similar hearing experience. A developmental and universal phonological acquisition process was observed. Developmental phonological rules were found in erroneous production. Articulatory complexity played an important role in vowels acquisition in CI groups. The result demonstrated a positive influence of cochlear implant on vowels production in Cantonese-speaking children.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

    中国南方地区罗非鱼无乳链球菌的分子流行病学研究

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    从广东省以及海南省等地区养殖的患病罗非鱼体内分离、收集到多株致病菌,经生化分析和分子生物学鉴定,均为无乳链球菌。对这些菌株分别进行了耐药谱测定、分子分型试验以及分子血清型分析。药敏试验结果表明,2007—2010年分离到的无乳链球菌耐药谱基本相似;多位点可变数目串联重复序列分析(MLVA)试验中,选择5个高变异指数的可变数目重复位点(VNTR)进行分子分型,结果表明,所有鱼源无乳链球菌菌株为同一MLVA型,而作为对照的牛源无乳链球菌则明显不同;为了对这些菌株进一步分型,分别进行了分子血清型和表面蛋白抗原基因的检测,结果表明,鱼源无乳链球菌的分子血清型均为Ⅰa型,表面蛋白抗原均为alpha-C蛋白。这进一步说明了不同年份和不同地区的鱼源无乳链球菌在基因水平上为同一分子类型,具有相同的起源或传染源。同时也说明,我国南方地区罗非鱼无乳链球菌在这几年中未发生明显的遗传变异。这些结果为罗非鱼无乳链球菌病疫苗研制,疫病监测及药物防治的研究提供理论依据

    The Research on Financial Risk Control in Abroad M&A——the Case Study of Lenovo

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    伴随全球化和一体化进程的逐步加快,我国企业跨国并购活动日渐兴起,成为促进我国对外投资持续增长和经济快速发展的重要推动力。但纵观我国企业跨国并购的历史来看,成功的并购案例只在少数。分析原因可以看到,财务风险控制问题始终是贯穿整个并购实践并严重影响并购活动进程与成败的关键。特别是在并购战略的决策分析、目标企业的价值评估、融资及支付安排、利率和汇率波动、并购后业务整合与信息共享等方面,对财务风险的处理不当将直接导致并购失败甚至使得企业财务状况走向恶化发生危机。 本文将跨国并购中的财务风险控制问题作为主要研究内容。结合联想并购具体案例,通过对并购前的准备阶段、并购实施阶段和并购完成后的整合阶段三个部...Accompanied by the increasingly advancing wave of globalization and integration, abroad mergers and acquisitions of Chinese enterprises is increasingly emerging, which is an important driving force to promote the sustained growth of China's foreign investment and rapid economic development. However, throughout the process of abroad mergers and acquisitions of Chinese enterprises, successful cases ...学位:管理学硕士院系专业:管理学院_会计学学号:1752010115114

    日本語を学んで

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    A Study on the Legend of Sesshoseki in the Kuju Region : Tamamo-no-mae Fables and the Legend of the Asahi Choja

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    本稿では,玉藻前説話における殺生石の破片が飛散した場所に関する伝説に着目し,大分県九重地方の豊後高田を取り上げ,現地調査の知見をもとに殺生石をめぐる伝承の意味について考察した。大分県の殺生石伝説は,当地の朝日長者伝説にまつわる七不思議の一つとされており,源翁和尚,玉藻前と切り離されているような印象がある。この理由を解明するために大分県の伝説,歴史など様々な文献を検討した結果,九重地方の殺生石伝説はあえて源翁和尚や玉藻前と切り離されたわけではなく,むしろ地元の田の神信仰との関わりが深かったため長者伝説にまつわるものとなっていったと推測できると結論づけた。departmental bulletin pape

    Multi-subject study on human resource management of staff in private colleges

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    深入探讨人力资源、人力资本和教师人力资源的本质特征,从教育法学、教育经济学等多学科的视角分析民办院校教师人力资源管理问题的实质、关键,从而可见确立教师人力资源管理理念具有理论和现实意义。Discussing the essential of human resource,human capital and human resource of staff in detail,analysing the essential of human resource management of staff at the angle of multi-subject,presenting that we should affirm the idea of human resource management

    民办学校教师人力资源管理问题探讨——温州民办学校教师留任与离职的调查分析

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    教师队伍建设是民办学校生存与发展的关键,对教师人力资源实施开发与管理刻不容缓。文章基于浙江温州市民办学校教师管理现状的调查,针对教师留任与离职环节分析,探讨改进民办学校教师管理工作的思路

    神社空間における観賞型祝祭環境の歴史的変遷に見る地域文化シーンに関する研究

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    茨城大学博士(工学)2024doctoral thesi

    公共利益本位视角下城乡规划变更实现机制探究

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    随着城市快速发展,城乡规划变更面临诸多问题,涉及土地价值、性质以及相关利益关系的重新分配,从而引发相关利益群体不同程度的利益\"受损\"或\"受益\"。基于公共利益本位,探讨规划变更实现的关键性问题,提出在规划变更过程中,利益相关人的参与有利于对规划行政主体进行监督与约束,从而实现行政权与公民权的\"平衡\";行政主体对\"受损\"的个人利益进行合理补偿,以实现公共利益与个人利益的\"平衡\",为我国城乡规划变更得以顺利实现提供可行思路
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