1,273 research outputs found

    Composition and size distribution of colloidal organic matter in the Chukchi Sea and Daya Bay: Application of asymmetric flow field-flow fractionation

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    本研究对非对称流场场流仪分离、测量海水中胶体有机物的方法进行了摸索和优化,并通过两个夏季航次的采样和分析,首次开展了楚科奇海和大亚湾胶体有机物光学性质及其粒径分布的研究,进而揭示楚科奇海和大亚湾胶体有机物的来源、组成等信息,获得如下主要认识: (1)建立了非对称流场场流仪分离、测量海水胶体有机物的方法,优化了样品进样体积,确定了以0.9%NaCl溶液作为分离海水胶体物质的载液;通过多次重复试验确定了最佳的粒径分离方案,评估了光学探头检测平行性、精密度和检出限;确定了采用蛋白类物质作为粒径校正的标准物质,可较准确地获得天然海水胶体有机组分的分子量。 (2)首次开展了楚科奇海胶体有机物光学性质...The separation and analysis method for marine organic colloids by Asymmetric Flow Field-Flow Fractionation (AF4) was optimized in this study. The properties and size spectra of colloidal organic matter in the Chukchi Sea and the Daya Bay in summer were firstly studied for elucidating the source and composition of colloidal organic matter. The main conclusions were obtained as follows. (1) The sep...学位:理学硕士院系专业:海洋与地球学院_海洋化学学号:2232013115137

    A Preliminary Study on the Baizhuduan Type

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    白主段类型是分布于福建闽江上游的富屯溪、崇阳溪、建溪、南浦溪、松溪等主要支流及其流域在内的广阔腹地的一支重要青铜时代早期考古学文化类型。白主段类型以甗形器、盆形鼎、罐类器、尊、瓮、豆、盂、钵、盆、杯等为基本陶器组合。其年代大致相当于中原地区的商代,下限或至西周初。本文在全面收集各类材料的基础上,界定了白主段类型的文化内涵,并通过对典型陶器形制的演变序列进行分析,将该文化类型划分为三段两期。第1段为白主段类型早期,年代大致相当于商代早期偏晚;第2段和第3段为其晚期前段与后段,年代大致相当于商代晚期,下限或至西周初。在分期的基础上,本文还探讨了白主段类型陶器群的文化因素构成,初步将之划分为8组因素...The Baizhuduan Type is one of the important archaeological culture types in the early period of Bronze Age,and its remains are distributed on the vast lands of the main tributaries(including Futun Stream,Chongyang Stream,Jianxi Stream,Nanpu Stream,Songxi Stream) and drainage basins in the upstream of Minjiang River,Fujian Province.Characterised by a pottery combination of Yan-shaped steamer, Ding,...学位:历史学硕士院系专业:人文学院_文物与博物馆硕士学号:1032013115234

    Research and Application of Vehicle CAN Bus printer based on uC/OS-II

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    由于车载网络总线的通信数据量的急剧增加,以及仪表显示参数信息的复杂化,仪表对仪表系统的性能提出更高的要求,越来越多的汽车仪表基于RTOS(实时嵌入式系统)进行应用功能的设计。基于嵌入式技术的CAN总线汽车仪表系统是借助计算机技术,提高仪表网络通信的抗干扰性能,最大限度地利用现有的软件、硬件成熟技术,提高了仪表的柔性,增强仪表数据交换通信的实时性能,迎合当代电子设备不断更新升级的步伐。 笔者在研究生期间负责某堆高机打印仪表方案的制定和整体设计,该仪表是比较典型、应用综合的嵌入式总线仪表,本文将围绕仪表涉及的知识和技术,分析总线特点、嵌入式应用、通信系统等内容,就开发基于uC/OS-II系统的C...Due to a sharp increase in the amount of communication data in vehicle networks, as well as the increasing complexity of the parameter information displayed by the in-strument,instrument put forward higher requirements on the performance of the in-strument system,more and more automobile instrument using RTOS (real-time em-bedded systems) to design application function. Auto instrument CAN system...学位:工学硕士院系专业:物理与机电工程学院_机械电子工程学号:1992012115271

    Research on residual stress measurement and vibration stress relief of sheet metal

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    小孔法的塑性效应会给高残余应力测量带来误差,为了解决这个问题,论文中对ASTME837-13a标准中的校准系数的塑性修正进行了研究。同时,组建了用于金属薄板件振动时效的电磁激振系统,研究了振动时效消除金属薄板件的残余应力。论文的研究内容围绕以下几个方面展开。 首先,研究了小孔法测量铝合金构件高残余应力的塑性效应修正方法。基于形状改变比能密度理论,对ASTME837-13a标准中的校准系数进行塑性修正;结合双线性弹塑性理论,采用ANSYS软件进行有限元仿真标定;使用电子万能试验机进行拉伸加载实验验证,修正前和修正后的高残余应力测量误差的平均值范围是0~80%和0~12%;使用ANSYS进行二轴...Plastic effect would lead to measurement error when high residual stress was measured using hole-drilling method (HDM). To solve the problem, the correction of calibration coefficients in the ASTM E837-13a standard was studied in this paper. At the same time, the system of electromagnetic vibration exciter for vibration stress relief (VSR) of metal sheet was formed and the VSR of sheet metal was s...学位:工程硕士院系专业:航空航天学院_工程硕士(机械工程)学号:1992014115291

    Theoretical and experimental investigations on Bi2Se3-based orange passively Q-switched Pr:ZBLAN all-fiber pulse lasers

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    可见光脉冲激光器在远距离探测、医疗和通信领域有着重要的应用。相比非线性倍频方法得到可见光,利用掺杂稀土离子光纤激射可见光,具有结构紧凑、简单和高效的优点。Pr3+离子是唯一在室温下可激射多种可见光波长的稀土离子。可见光波段在普通石英光纤中有较大的传输损耗,而ZBLAN光纤因为声子能量很低,仅为580cm-1,且在可见光波段传输损耗小(Visible pulse lasers play an important role in remote sensing, medicine, and communications. Compared to second-harmonic visible lasers, rare-earth-doped visible fiber lasers offer compact construction, are maintenance-free, and have high efficiency. Pr3+ is the only rare earth ion that emit multi-wavelength in visible range at room temperature. Furthermore, ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) fiber p...学位:工学硕士院系专业:信息科学与技术学院_光学工程学号:2312014115309

    Perparation of supported phosphide catalysts and theirs application in biomass hydrodeoxygenation

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    生物质能因其原料存储丰富,可再生等优势可作为很好的替代能源。但生物质存在大量含氧化合物,极大的影响了热稳定性,限制了其广泛应用。因此需对生物质进行加氢精制处理。过渡金属磷化物催化剂因其具有良好的加氢脱氧性能,近几年来受到广泛关注和研究。 本论文采用溶胶凝胶法和柠檬酸凝胶法分别制备Pd@Ni2P/SiO2和FeMoP/SiO2催化剂。通过CO化学吸附、XRD、XPS、NH3-TPD、STEM等表征对催化剂进行分析,考察了Pd@Ni2P/SiO2和FeMoP/SiO2催化剂对苯酚加氢脱氧以及丙三醇氢解反应的催化性能。 研究表明,Pd@Ni2P/SiO2催化剂颗粒分散均匀(6.75±1.54nm...Biomass has been used as an alternative source of energy due to its rich storage, renewable and other advantages. However, oxygen containing compounds in biomass greatly affects the thermal, and limits its wide application. Therefore, it is necessary to carry out hydrodeoxygenation for biomass. Among these catalysts investigated for hydrorefining, transition metal phosphide catalyst with excellent...学位:工学硕士院系专业:化学化工学院_化学工艺学号:2062013115146

    Jarid2 regulates the function of follicular helper T cells and immune responses

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    免疫系统是人和动物体内帮助抵御入侵病原体和清除体内肿瘤细胞的防御系统,高等动物的免疫系统包括天然免疫系统和适应性免疫系统。适应性免疫可分为T细胞介导的细胞免疫应答和B细胞介导的体液免疫应答。生发中心(GerminalCenter,GC)反应是体液免疫应答中最重要的生理过程,活化的B细胞只有通过生发中心选择,才能分化成为分泌高亲和力抗体的浆细胞及长期记忆性B细胞,而生发选择过程是受到滤泡辅助性T细胞(FollicularhelperTcell,TFH)的控制。因此TFH细胞分化及功能的机制研究为体液免疫应答和免疫记忆形成提供重要的理论基础。 越来越多的研究表明,表观遗传修饰在各种免疫细胞的分化...The immune system protects host from invading pathogens and clears tumor cells. The vertebrate immune system is comprised of innate and adaptive immune system. Adaptive immunity can be classified into T cell-mediated cellular immunity and B cell-mediated humoral immunity. The germinal center reaction is the most important physiological process in humoral immunity. Only through germinal center sele...学位:理学硕士院系专业:生命科学学院_生物化学与分子生物学学号:2162014115254

    the Research and Design of WEB Application Based On RIA

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    在这个互联网技术飞速发展的时代,传统的基于C/S和B/S设计模式的Web应用程序已经不能满足用户日益增长的要求。人们需要一种新的技术,能够轻松构建更为直观、易于使用、反应更迅速、并且可以脱机使用的Web应用程序。于是富互联网应用程序(RichInternetApplication,简称RIA)技术呼之欲出,并随着互联网的发展和普及蓬勃发展。RIA技术结合了桌面应用程序的反应速度快且交互性强的优点,以及Web应用程序的传播范围广且易于传播的特性,具有良好的用户体验性、跨平台兼容性,并提供快速的开发、部署以及高度的个性化配置的功能,给用户和企业带来了诸多方便和实惠,成为如今最热门的新一代Web应用...Standing at the contemporary stage of Internet Technology rapidly developing, the conventional Web applications are no longer satisfied by gradually increasing users’ requirements, which are based on C/S and B/S design style previously. Hence, the need for a new technology mushrooms promptly, which can fulfill the requirements to construct the Web applications more intuitive, convenient with less ...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X200823003

    Seasonal and Spatial Variation of Dissolved Inorganic and Organic Carbon in Taiwan Strait and the adjacent Sea Area

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    海洋作为地球上最大的碳库之一,在全球碳循环中起着非常重要的作用;溶解无机碳(DIC)和溶解有机碳(DOC)是海洋碳库的重要的组成部分,它们在海洋中的分布、迁移和转化是海洋碳循环的关键环节。近海陆架区连接陆地与大洋,受陆源径流输入、人为活动扰动、高生物生产力、复杂的水动力过程等多种因素的共同影响,碳循环过程及其机制比较复杂。因此,开展陆架海区DIC和DOC时空分布及其影响因素的研究,对于揭示海洋中碳的生物地球化学循环的调控机制具有重要的典型意义。本论文选取台湾海峡及其邻近海域为研究区域,利用2006年07月~08月、2006年12月~2007年02月、2007年4月~5月,2007年10月~20...As one of the largest carbon pools, the ocean plays an important and decisive role in global carbon cycle, of which dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are the important and main components, therefore, their distribution, transport and transformation are getting more and more attention of oceanographers. In this thesis, the distribution and influencing factors of or...学位:理学博士院系专业:海洋与环境学院_海洋化学学号:B2005140316

    我国网上银行业务的发展与规管

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    网上银行业务的出现极大改变了银行的经营环境,对金融业和金融市场产生了多重的影响。我国银行业应高度重视网上银行的起步和发展问题,早作策划,尽快形成规模,以迎接迫在眉睫的挑战
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