278 research outputs found

    Research on Beamforming and Sparse Array Based on Convex Optimization

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    基于阵列天线在无线电系统中各种应用,使阵列综合的研究十分重要。本文根据实际应用系统中的各种需求,结合凸优化的高效、快速以及局部最优解也是全局最优解的优点,研究了各种阵列综合问题及基于凸优化思想的解决方案。 首先,本文基于凸优化算法对理想点源以及考虑阵列天线辐射方向图的阵列的综合方法进行了全面的概述,包含了阵列的无目标优化、最小副瓣优化、最大方向性优化、最大效率优化以及最小阵元数目的优化。并且,针对每个优化目标给出了相应的仿真例子,用以验证相应的综合方法的有效性。 其次,本文提出了矢量场的阵列综合方法。根据给定的期望极化方向,定义了扫描波束的期望主极化和交叉极化方向,并进一步给出了主极化方向...Based on the application of array antenna on radio systems, research on array synthesis is very important. According to the requirements of application system in practical, combing convex optimization with advantages of efficient, fast, and local optimal solution equal to global solution, a variety of array synthesis problems and their solutions based on convex optimization are studied in this pap...学位:工程硕士院系专业:物理科学与技术学院_工程硕士(电子与通信工程)学号:3312013115285

    Design and Implementation of Art Sales Platform

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    随着Internet的快速发展,人们的生活和Internet的关系越来越密切。如何更好的利用Internet来提高人们对艺术文化的了解,是本文的主要研究内容。网络艺术品销售平台随着电子商务的的快速发展,作为电子商务的一种形式是高效率,低成本的优势,逐步成为新兴的经营模式和理念,人们已经不再满足使用信息的浏览和发布,而是充分享受网络的便利。网络购物正适应了当今社会的生活节奏快,使客户足不出户就能方便快捷轻松地选购自己喜欢的艺术品。 本文综合应用软件工程学,社会工程学的相关内容进行艺术品销售平台的设计。本设计实现的网艺术品销售平台选用.NET为系统开发工具,MicrosoftVisualStud...With the rapid development of Internet, the relationship between people's life and Internet is becoming more and more closely. Internet how to better utilize to improve people's understanding of art and culture, is the main content of this paper. Network art sales platform along with the rapid development allowing customers to remain within doors can be easily and quickly and easily purchase the c...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X201123036

    Construct the TNFAIP8 interference and prokaryotic expression vector and prepare TNFAIP8 antibody

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    恶性肿瘤的发病率在世界范围内逐渐增高,而肿瘤的发生与一些肿瘤相关基因的改变相关,即癌基因与抑癌基因之间的平衡被打破造成的,非正常的生活方式、各种污染、激素变化、辐射、药物及基因等因素也是其诱因。 肿瘤坏死因子α诱导蛋白8(tumornecrosisfactorαinducedprotein-8,TNFAIP8)是转录因子NF-κB可诱导的抗凋亡,致癌分子,分子量为21kD的胞浆蛋白。TNFAIP8在肾癌及乳腺癌中高表达,过表达的TNFAIP8可导致乳腺癌、肺癌、肾细胞癌和食管鳞状细胞癌的进展,因其在细胞凋亡信号转导、肿瘤发生、侵袭及转移过程中具有重要调控作用而逐渐成为研究的热点。 为了...Irregular lifestyles, pollution, radiation, hormone changes, drugs, genes and other factors are causing the incidencement of growing malignant tumors all over the world, while cancers are due to the changes of tumor-related genes, that is breaking the balance between oncogenes and tumor suppressor genes. Tumor necrosis factor alpha induced protein 8 (tumor necrosis factor- α inducedprotein-8,...学位:理学硕士院系专业:医学院_药理学学号:2452011115339

    Research on Nitrogen Reduction Processes in Fujian Mangrove Sediments Using Nitrogen Stable Isotope in China

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    近年来,由于人类活动频繁,导致大量营养盐输入水生系统中,造成严重的富营养化,威胁水生生物生长,污染饮用水,同时破坏水体的娱乐用途。当输入系统的氮不能通过生物地球化学作用被河流移除或滞留时,过量的氮大都带入海岸带河口,最终进入大陆架作为重要的氮汇途径,而这些过量氮素将会引起近岸海域富营养化及一系列环境问题。红树林是分布在热带和亚热带海岸河口地区潮间带开放的生态系统。其栖息地—海岸潮汐湿地—作为河口沉积区的重要组成,是全球碳、氮、磷的重要源、汇及转化器,因此成为了研究的热点。 本研究以我国东南沿海的不同区域红树林沉积物为主要研究对象,利用15N稳定同位素技术进行定位监测分析,通过室内培养测定红树...In recent years, a large number of nutrient discharge intothe aquatic system due to frequent human activities, causing serious eutrophication, threatening the growing of aquatic organisms, polluting drinking water, and destroying the recreational use of water at the same time.When the nitrogen discharging into system cannot be removed or stranded through the biogeochemical effects, excessive nitro...学位:理学硕士院系专业:环境与生态学院_环境管理学号:3312014115172

    Studies on the Promoting Effect and Catalytic Performance of Brønsted and Lewis Acids for Hydroesterification and Hydroalkoxylation of Olefins

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    烯烃通过加成反应引入官能团,将赋予产物丰富的物理化学性质,有着广泛的工业应用背景。烯烃、CO和醇在催化剂存在下进行的氢酯化反应,即Reppe反应,是羰基合成反应的重要组成部分,也是从烯烃出发合成多一个碳原子的羧酸酯的重要反应,该催化反应除需要过渡金属配合物催化剂外,通常需B酸或L酸作为促进剂;而烯烃和醇在酸催化剂存在下发生的氢烷氧基化反应,则是合成烷基醚的重要方法。这两类反应均属于烯烃定向加成反应之列,且具有“原子经济型”反应的特征和对环境友好的优点,一直倍受学术界和产业界的关注。本学位论文以烯烃氢酯化反应和烯烃氢烷氧基化反应为目标反应,研究了B酸和L酸的种类、结构和酸性等对其促进/催化作用,...The functionalization of olefins via addition reaction can endow the corresponding products with rich physical and chemical properties, which allow them to find broad applications industrially. The hydroesterification of olefins, known as a Reppe carbonylation, using CO and alcohols in the presence of transition metal complexes is an emerging technology for producing industrially valuable carboxyl...学位:理学博士院系专业:化学化工学院化学系_物理化学(含化学物理)学号:2052006015326

    la traduction dans la perspective interculturelle

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    翻译不仅仅是一个语言问题,也是一个跨文化问题。当前,翻译被认为是一种跨文化交际活动。语言、文化、翻译三者紧密联系,不可分割。文化与语言的密切关系,已成为大家的共识。语言是文化的载体,文化又深深植根于语言。人类自有文化就有交流,交流促进发展,但是文化交流必须通过翻译,没有翻译就没有文化交流。一个好的译者,不仅要熟练掌握两种语言,而且要了解两种不同文化。译者在某种程度上就是文化大使。但是,不同民族存在思维方式、信仰、价值的差异,存在着文化的差异。中西方生活环境和人文历史也有很大不同,这些差异沉淀在文化中,不仅会造成跨文化交际的失误和误解,而且是翻译理论家和翻译工作者遇到的难题。面对文化差异的难题,...La traduction n'est pas seulement un acte linguistique. Il s’agit aussi de la communication interculturelle. Actuellement, la traduction est considérée comme une activité interculturelle qui transmet une culture à l'autre. La langue, la culture et la traduction ont des liens très étroits entre elles. La culture et la langue sont inséparables. La langue est un véhicule privilégié de la culture. Ell...学位:文学硕士院系专业:外文学院外文系_外国语言学及应用语言学学号:20030406

    Research on Interaction and Perceived Distinction of Factors Influencing on Tourism on-site Experience

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    随着我国旅游市场的日渐成熟,旅游者已从单纯的购买旅游产品向追求高品质的旅游体验转型。旅游在场体验是旅游体验最重要的组成阶段,作为旅游者在旅游目的地游玩的主观感知,旅游在场体验直接影响旅游者的旅游满意度甚至旅游忠诚度的形成,因此旅游在场体验及其影响因素的研究对于旅游目的地品牌塑造、旅游企业产品开发、旅游者高品质旅游体验的获得都具有十分重要的意义。 本研究以旅游在场体验为主题,结合交互行为场、情境理论和“刺激—机体—反应”等理论对旅游在场体验的影响因素进行研究。创新点主要有现反应”等理论对旅游在场体验的影响因素进行研究。创新点主要体现在:(1)对旅游在场体验的多种基础理论进行整合研究,对真实性、...With the development of Chinese tourism industry and maturity of tourism market, tourist’s attitude is beening changed from just purchasing the travel products to focusing on high-quality tourism experience. As the subjective perception of tourists in destination and most important stage of the tourism experience, tourism on-site experience has a direct impact on tourist’s satisfaction and loyalty...学位:管理学博士院系专业:管理学院_旅游管理学号:1782009015323

    Research on Coordination Mechanism of Tourism Supply Chain Based on the Multi - Structure

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    供应链管理是目前较为流行的管理模式,旅游供应链主要研究的是旅游经济活动中企业与企业之间相互关系的一个概念,旅游供应链目的在于降低成本费用、实现旅游企业合作利益最大化,而协调则是旅游供应链实现这些目标的基础和必要的前提。 本文以旅游供应链协调为研究对象,在结合国内外相关理论研究成果的基础上,利用契约理论、博弈论、信息经济学和生产外部性理论,通过对旅游供应链运营的问题分析,结合旅游供应链的结构关系和独有特点,选取了供应链中的产品流、信息流、资金流、知识流为协调机制要素,有目的、有重点的对产品生产的外部性、旅游产品的推动协调模式、信息不对称的“逆向选择”等问题进行深入分析,构建了微观以旅行社为协调...Supply chain management is a popular mode of management, and tourism supply chain is a new concept for describing the interrelations between tourism enterprises in tourism economic activity. The purpose of tourism supply chain is to decrease transaction cost and maximize the interests of tourism enterprises in cooperation. Coordination is the foundation and a necessary prerequisite for the tourism...学位:管理学硕士院系专业:管理学院旅游系_旅游管理学号:1782006115141

    The review of the research on Japanese translation teaching method in Chinese universities

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    This paper analyzes 30 academic papers on the research of Japanese translation teaching method in Chinese universities which are included in CNKI in recent 20 years (1995~2014), and the following four conclusions can be drawn: (1) There are only a small number of papers on Japanese translation teaching method from 1995 to 2009, and its correlated studies have gradually increased from 2010; (2) The depth and breadth of the study is not enough, and the empirical research is so limited; (3) The papers mainly on the translation teaching method are not dominant in numbers; (4) The researchers in the foreign studies universities pay less attention to this field, and there is no correlated paper

    Optimal Directivity Synthesis of an Arbitrary Array Subject to Sidelobe and Cross-Polarization Constraints

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    本文根据给定的期望极化方向,定义了扫描波束的期望主极化和交叉极化方向,并进一步给出了主极化方向性系数的定义,它可以更为准确的表征天线集中辐射主极; 化分量的程度.在没有副瓣约束和交叉极化约束的条件下,给出了任意阵列主极化方向性系数最优解的解析表达式.并且,在含副瓣约束、零陷约束以及交叉极化约; 束的条件下,我们发展了一种基于凸优化的高效数值综合方法,实现多约束条件下的主极化方向性系数的优化.数值阵列综合结果表明了本文所提出的最优主极化方; 向性系数解析解的正确性,以及这种可以综合考虑副瓣约束、零陷约束和交叉极化约束的数值方向性优化方法的有效性.Definitions of the desired co-polarization and cross-polarization; directions are given for a scanned beampattern according to a desired; polarization direction. Furthermore, the co-polarization directivity is; defined to more accurately represents the degree of the concentration of; co-polarization field over the total radiated power. With this; definition, the co-polarization directivity can be optimized. Its; analytical expression can be derived when no more pattern constraints; exist. In more general cases in which the constraints on the sidelobe; level,nulling points and cross-polarization level exist, an efficient; numerical algorithm based on convex optimization is proposed. Some; numerical synthesis experiments are conducted, and the results show the; effectiveness and robustness of the proposed synthesis techniques.国家自然科学基
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