315 research outputs found

    Investigation on optimal thermoeconomic and thermodynamic performances of the refrigeration cycles using ferromagnetic or Gd-based material as the working substance

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    当今社会,能源紧缺和环境污染问题日益突出,探寻节能环保的新制冷技术正吸引着越来越多的注意力。具有高效节能、绿色环保、噪音小、结构紧凑的室温磁制冷技术是一种很有潜力的新一代制冷技术的备选。目前,室温磁制冷仍有几大指标需要突破。一是提高制冷机的制冷功率,二是提高制冷机的制冷温跨,三是提高制冷机的热经济性能。当今室温磁制冷发展的两大方向:其一是探索具有高磁热特性的室温磁制冷材料,其二是研制制冷性能指标优的室温磁制冷机。本学位论文是要在提高室温磁制冷机循环的热力学性能和热经济性能方面作出新的有益贡献,主要包括如下几方面: 首先介绍磁制冷材料的基本理论及其热力学关系式,综述磁制冷循环的热力学性能和热经...The problems of energy crisis and environment polution are becoming more and more serious for today's society. To explore some new refrigeration technologies with energy conservation and environment friendly is attracting increasing attentions. Room-temperature magnetic refrigeration (RTMR) is a promising alternative of new generation of refrigeration technology, which has a lot of advantages such...学位:理学博士院系专业:物理科学与技术学院_凝聚态物理学号:1982012015390

    The systematic simulation and performance analysis of biomass gasification fuel cell-gas turbine and ground source heat pump combined cycle

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    生物质气化、地源热泵、燃料电池与燃气轮机联合循环等技术以其清洁、高效、环保等特性,近年来得到国内外众多学者和研究机构的广泛关注。目前针对这几类单项技术的研究已经取得了较多成果,但将这些单项技术进行集成耦合后形成联合循环对其进行系统分析的研究还处于起步阶段,系统的结构、循环的设计、不同单元的规模匹配、部件之间的相互耦合等尚未形成完整的理论体系,需要进行详细的分析和论证。 本文由此提出生物质气化燃料电池-燃气轮机与地源热泵(BGFC-GT-GSHP)的一体化联合循环系统,基于gPROMS软件对系统的关键部件及过程进行了建模,包括生物质气化单元、燃料电池单元、燃气轮机单元、热泵单元、地埋管单元、部...The technologies of biomass gasification, ground source heat pump, fuel cell and gas turbine combined cycle have received much attention in recent years from scholars and research institutions for their clean, energy efficient and environmentally friendly features. There have been a few studies on these technologies, however the research on the combined system with these technologies integrated to...学位:理学硕士院系专业:能源研究院_核工程与材料学号:3242012115212

    Design and Implementation of Student Status Management System Based on B/S Architecture

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    学习信息管理的难度大幅度增加。对于高校教务管理人员而言,学籍管理工作变 得越来越复杂。而从另一个方面看,学籍管理的高效性、安全性和完整性也变得 越来越重要,甚至直接决定着高校的管理质量。随着信息技术的不断进步,各类 信息技术已经广泛应用于高校管理工作中,不仅可以降低管理成本,还可以提升 管理质量。签于当前高校学籍管理工作所面临的诸多问题,基于信息技术开发设 计出一套学籍管理系统是十分重要的,具有一定的应用价值和现实意义。 本文正是基于此背景,以学生学籍管理问题为研究对象,以C#作为开发语 言,以ASP.NET作为开发平台,以SQLServer为数据库管理工作,开发设计出 了一套...With the continuous expansion of college enrollment, the domestic college students are also increasing, which make the difficulty of learning information management has greatly increased. For the educational administration personnel in colleges and universities, student status management work is becoming more and more complex. But look from another aspect, efficiency, security and integrity of...学位:工学硕士院系专业:软件学院_工程硕士(软件工程)学号:X201323092

    HREELS investigations of Oxygen absorption and oxidation of Mo(110) surface

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    模型催化一直以来都是表面科学的研究热点。模型催化研究通过在单晶表面构建二 维模型催化剂,在理想条件下简化催化过程。其目的是为了研究催化反应机理,建立催 化剂结构与性能之间的微观联系,从而指导实际催化剂的合成与改进。制备规整结构的 表面氧化物膜是其中关键的一步。 通过HREELS,AES和LEED,本论文研究了Mo(110)表面与氧的相互作用,包括 氧在Mo(110)表面的吸附,Mo(110)的氧化和氧化钼膜的制备。HREELS发现在0.67ML 覆盖度下,大部分氧吸附在Mo(110)的穴位(600cm-1)上,还有少部分吸附在长桥位 (513cm-1)上。随着覆盖度的增加,Mo(...The chemical interaction between oxygen and transition metal surface is of considerable research and practical importance, which is common and crucial for many industrial oxidation reactions, and has attracted much attention in surface science. Oxygen absorption and the intense oxidation of the Mo(110) surface were studied by means of HREELS, AES and LEED. At 0.67 ML, most O ad-atoms reside in...学位:理学硕士院系专业:化学化工学院_物理化学学号:2052011115165

    Research on Olympic Marketing--A study of Tsingtao Beer and Snow Beer

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    2008年北京奥运会的举办为企业提供了千载难逢的发展机会,为企业的品牌形象建构、知名度、美誉度的提升提供了一个盛大舞台,也让更多的企业有了梦想照进现实的机会。 由于我国承办奥运尚属首次,我国企业的奥运营销经验也尚且疏浅,我国企业针对奥运展开的营销计划和活动还处于摸索阶段。在2008年奥运会中,虽然小部分企业出色地完成了奥运营销,但是大部分企业无论在奥运营销战略选择与制定、具体实施、营销成果等方面的表现都差强人意。尤其值得注意的是,我国企业在奥运营销中呈现出缺乏自身实力理性评估;缺乏对奥运营销长期性、系统性的认知;战术选择失当;执行欠火候等多个方面的问题。因此,是否采取奥运营销战略、如何有效地...The successful host of the 29th Olympic Games in Beijing offers Chinese enterprises precious opportunities to develop faster. As a result, Chinese enterprises are provided with an advanced platform to improve their corporate images as well as their reputation. Moreover, many chances come flooding in, which make it possible for many enterprises to realize their dreams. Since this is the very first...学位:文学硕士院系专业:新闻传播学院广告学系_传播学学号:1052006115028

    Research on Sentiment Analysis Based on Conditional Random Fields

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    伴随着互联网的发展以及新的网络应用的出现,互联网用户由单纯的“读”网页,向“读、写”网页,共同建设互联网发展,由此网上产生了大量带有用户主观感情的数据,从这些带有主观感情的海量数据中挖掘出网络用户的观点在现实生活中具有很大的意义,在这种背景下文本情感分析(sentimentanalysis)技术应运而生。 文本情感分析近年来成为一个新的研究热点。根据研究的粒度大小不同,文本情感分析可分为词汇级、句子级以及文档级,然而句子级以及文档级的情感分析往往以词汇级的为基础。目前对于词汇级的情感分析研究有基于规则的方法和基于机器学习方法,针对中文文本词汇级情感分析大部分使用基于规则的方法。基于规则的方法...With the rapid development of Internet and the emergency of new network application, Users of Internet begin to "writing" page and join in the construction of the Internet from only "reading" page. And more and more subjective data with users' sentiment is created by Internet users, and It's more useful of the summarized sentiment retrieved from the subjective data. Under this context, text sentim...学位:工学硕士院系专业:信息科学与技术学院计算机科学系_计算机软件与理论学号:2302009115271

    A Research on Marketing Improvement Of Xiamen Container Terminal Group Co. Ltd.

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    厦门港地处上海与广东之间,是中国东南沿海的一个天然良港。它面向东海,毗邻台湾海峡,与台湾、澎湖列岛隔海相望,是我国东南沿海的重要通道,入闽的主要门户。厦门港具有水域宽阔、不冻、少雾、避风条件好及航道水深、少淤等优点,万吨级巨轮可以随时进出港区。厦门港开港于1843年,历史上就是我国东南沿海对外贸易的重要口岸。如今厦门港是厦门经济特区的一部分,厦门最突出的优势条件就是港口。随着“以港立市、以港兴市、以港强市”战略的提出,厦门港被厦门市作为未来最具优势的产业来发展,厦门港的建设得到政府越来越多的支持。为推动海峡西岸经济区的开放和发展,经厦门市政府研究,决定实施厦门港集装箱码头资源整合。厦门集装箱码...The Xiamen port is a natural excellent harbor along the southeast coast of China, located between Shanghai and Guangdong. It faces the East Sea, being adjacent to the Taiwan Strait and bordering Taiwan and the Penghu Islands across the water, and is considered as the strategic position in the southeastern coastal areas of China and the portal of Fujian province. The Xiamen port has a lot of advant...学位:工商管理硕士院系专业:管理学院_工商管理硕士(MBA)学号:1792012115094

    Research and Design of Embedded ASSR System Based on DSP

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    多频稳态诱发反应(MultipleFrequencyAuditorySteady-StateResponse,ASSR)是近年来才发展起来的一种新的客观听力检测技术,具有客观性,频率特异性好,最大输出强度高,不受睡眠和镇静药物的影响,而且检测速度快等优点,因此具有很高的临床应用价值。我国卫生部已经将ASSR检测作为人工耳蜗听阈检测和新生儿听力筛查的参考设备。目前我国还没有自主研发的多频稳态测试仪,都是从国外进口,价格昂贵,不便于推广,而且硬件电路复杂,不易维修和调试,因此本课题设计了基于DSP的嵌入式ASSR听力检测仪,能够填补国内在这方面的空白。 本文首先阐述了基于DSP的嵌入式ASSR检...Multiple Frequency Auditory Steady-State Response (ASSR) is a new objective audiometry which has been developed in recent years. It has good frequency-specific and maximum high output intensity, and is not likely to be affected by sleeping state or anesthesia medicine. Therefore, the clinic value of ASSR is promising. Ministry of Health has announced that ASSR system is reference for threshold est...学位:工学硕士院系专业:软件学院_计算机应用技术学号:20044001

    二元反平均剩余寿命的一些性质

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    将反向的平均剩余寿命推广到了二元的版本,并研究了其联合分布函数与二元反平均剩余寿命的联系,同时还给出了其比例模型的重要性质.国家自然科学基金(10201010)新世纪优秀人才计划资助项目

    以骨为证:破译中华民族的开天辟地——访厦门大学人类学研究所王传超教授

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    文章是对厦门大学分子人类学研究的王传超教授专访,介绍了王传超教授复旦大学毕业之后进入美国哈佛医学院和德国马普所进行古DNA的研究经历以及分子人类学的发展概况。王传超教授团队所开展的分子人类学研究是通过对更多的考古墓葬和遗址的古代样本取样提取DNA,建立起一条时间轴线来研究古今人群关系,尤其对丰富和完善东亚人群历史有重要意义
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