145 research outputs found
大洋溶解铁的物质来源及其同位素示踪
铁(Fe)作为海洋初级生产所必需的微量和限制性营养元素影响着海洋生物群落结构、生态功能以及碳循环,理解溶解Fe的物质来源及其对气候变化的响应具有重要的科学意义。早期研究多强调风尘输入是维持大洋Fe循环的主要机制。近年来,随着海水Fe分析数据的积累,尤其是痕量元素及其同位素海洋生物地球化学循环研究计划(GEOTRACES)的开展,陆架沉积物和热液活动所释放Fe的贡献开始越来越受到重视。尽管如此,不同物源对开阔大洋溶解Fe的影响依然存在相当的不确定性。以海水溶解Fe的化学组分为出发点,强调有机配体对大洋Fe循环的决定性作用,综述了不同来源Fe的通量估计和第四纪大洋Fe来源的研究争议。铁同位素为理解大洋Fe的物源演变提供了新的工具。讨论了不同物源的Fe同位素特征,并提出结合沉积物的活动性Fe同位素和组分研究可能为理解过去陆架-热液活动-风尘输出与输运Fe的机制提供全新视角。西太平洋地球系统多圈层相互作用重大计划培育项目“上新世以来西太平洋沉积铁同位素演化研究”(91858105)国家海洋局海洋沉积与环境地质重点实验室开放基金资助项目“晚第四纪北太平洋深水铁同位素演化重建:对大洋铁循环的新约束”(MASEG201711)青岛海洋科学与技术试点国家实验室海洋地质过程与环境功能实验室创新团队资助项目“利用西太平洋铁锰结壳微量金属重建新生代火山喷气历史”(MGQNLM-TD201701
Evaluation of chemiluminescence immunoassays kits for detection of influenza A virus
目的考核甲型流感化学发光检测试剂的灵敏度和特异性。方法分别利用病毒分离培养液和入境人群的鼻咽拭子标本考查甲型流感试剂盒的检测灵敏度和特异性。结果化学发光法对H1、H3、H5、H7、H9等亚型的甲型流感病毒株均有很好的检出率,灵敏度明显优于flu A-dOT和dIrECTIgEn Ez flu A;对102份入境人群鼻咽拭子标本的检测灵敏度为97.62%。结论甲型流感化学发光检测试剂具有很好的灵敏度和特异性,适用于口岸现场的甲型流感快速筛查。Objective To evaluate the sensitivity and specificity of chemiluminescence immunoassays kit for detection of influenza A virus.Methods To analyze the sensitivity and specificity of three different assay kits for detection of influenza A virus by using the viral culture liquid and nasopharyngeal swabs from entry-exit travelers.Results The chemiluminescence immunoassays kit had a good detection rate when it was tested against a panel of influenza A virus strains(H1/H3/H5/H7/H9),and its sensitivity was much better than Flu A-DOT kit`s and Directigen EZ Flu A kit' chemiluminescence immunoassays kit used for the detection of 102 nasopharyngeal swabs from entryexit travelers had a detection sensitivity of 97.62%.Conclusion Chemiluminescence immunoassays kit had good sensitivity and specificity, which was fit for the rapid detection of influenza A virus at frontier ports.国家质检总局科技计划项目(2014IK045); 厦门市科技惠民项目(3502Z20144083
Performance of the fuel injector in supersonic combustor
Enhancing the fuel-air mixing is critical for scramjet combustor performance. The performance of four different aerodynamic ramp injectors was reported in this paper. The experiments were conducted in a direct-connected scramjet test facility. The concentration profiles were obtained by gas sampling and chromatogram analysis. The pictures of the flow field were obtained by using laser scatter. It would be used to analyze the flow field generated by the aerodynamic ramp, then optimize the layout of the injectors. The results would offer some useful information for engine design. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc
Measurement of temperature, velocity and water vapor concentration in a scramjet combustor based on nearinfrared diode laser absorption
A multi-channel Tunable Diode Laser Absorption Spectroscopy (TDLAS) system was designed and constructed for flow parameters diagnostics in a scramjet combustor. Two fiber coupled distributed feedback (DFB) lasers with narrow line width were used to probe two H2O absorption features (7185.597cm-1,7444.35cm-1+7444.37cm-1(c ombined)) by using direct absorption Time-Division-Multiplexing (TDM) strategy at a 4-kHz repetition rate. Laser light was split into five beams and transmitted across the test region. Two motorized precision translation stages were used to move the collimators during the test, so that the three beams located near the cavity and at the exit of the combustor can scan the cross sections respectively. Flow parameters could be obtained simultaneous which included average temperature, water vapor concentration and velocity at the entrance of the combustor, the distribution of temperature, water vapor concentration at a cross section near the cavity, the distribution of temperature, water vapor concentration and velocity at the exit cross section of the combustor. The parameters of the flow entering and exiting the combustor could be used to evaluate the performance of the direct-connected scramjet facility and the combustion efficiency of the combustor. The parameters at the cross section in the combustor could also be used to analysis combustion characteristics in the combustor
Plasma-assisted ignition for a kerosene fueled scramjet at Mach 1.8
By using a plasma jet (PJ) torch with 1.5 kW input power as an igniter, successful ignition for liquid-kerosene fueled combustion experiment was conducted in a direct-connected supersonic test facility. The incoming flow has total temperature of 950 K and local Mach number of 1.8, corresponding to Mach 4 flight condition. In this study, several optical techniques, including high speed photography, high speed schlieren photography, and planar laser scattering (PLS) technique, were combined to study the ignition process, flame propagation, and mixing features of liquid kerosene fuel with air around the cavity. The effect of fuel injection position, injection pressure, and feedstock gas on ignition performance has been analyzed. The results indicate that local mixing is a critical factor for ignition. It is also shown that the PJ torch with N-2 + H-2 feedstock is superior to the PJ torch with N-2 feedstock for the ignition of liquid-kerosene fuel. These results are valuable for the future optimization of kerosene-fueled scramjet engine when using a PJ torch as an igniter
中国物理海洋学研究70年:发展历程、学术成就概览
本文概略评述新中国成立70年来物理海洋学各分支研究领域的发展历程和若干学术成就。中国物理海洋学研究起步于海浪、潮汐、近海环流与水团,以及以风暴潮为主的海洋气象灾害的研究。随着国力的增强,研究领域不断拓展,涌现了大量具有广泛影响力的研究成果,其中包括:提出了被国际广泛采用的"普遍风浪谱"和"涌浪谱",发展了第三代海浪数值模式;提出了"准调和分析方法"和"潮汐潮流永久预报"等潮汐潮流的分析和预报方法;发现并命名了"棉兰老潜流",揭示了东海黑潮的多核结构及其多尺度变异机理等,系统描述了太平洋西边界流系;提出了印度尼西亚贯穿流的南海分支(或称南海贯穿流);不断完善了中国近海陆架环流系统,在南海环流、黑潮及其分支、台湾暖流、闽浙沿岸流、黄海冷水团环流、黄海暖流、渤海环流,以及陆架波方面均取得了深刻的认识;从大气桥和海洋桥两个方面对太平洋–印度洋–大西洋洋际相互作用进行了系统的总结;发展了浅海水团的研究方法,基本摸清了中国近海水团的分布和消长特征与机制,在大洋和极地水团分布及运动研究方面也做出了重要贡献;阐明了南海中尺度涡的宏观特征和生成机制,揭示了中尺度涡的三维结构,定量评估了其全球物质与能量输运能力;基本摸清了中国近海海洋锋的空间分布和季节变化特征,提出了地形、正压不稳定和斜压不稳定等锋面动力学机制;构建了"南海内波潜标观测网",实现了对内波生成–演变–消亡全过程机理的系统认识;发展了湍流的剪切不稳定理论,提出了海流"边缘不稳定"的概念,开发了海洋湍流模式,提出了湍流混合参数化的新方法等;在海洋内部混合机制和能量来源方面取得了新的认识,并阐述了混合对海洋深层环流、营养物质输运等过程的影响;研发了全球浪–潮–流耦合模式,推出一系列海洋与气候模式;发展了可同化主要海洋观测数据的海洋数据同化系统和用于ENSO预报的耦合同化系统;建立了达到国际水准的非地转(水槽/水池)和地转(旋转平台)物理模型实验平台;发展了ENSO预报的误差分析方法,建立了海洋和气候系统年代际变化的理论体系,揭示了中深层海洋对全球气候变化的响应;初步建成了中国近海海洋观测网;持续开展南北极调查研究;建立了台风、风暴潮、巨浪和海啸的业务化预报系统,为中国气象减灾提供保障;突破了国外的海洋技术封锁,研发了万米水深的深水水听器和海洋光学特性系列测量仪器;建立了溢油、危险化学品漂移扩散等预测模型,为伴随海洋资源开发所带来的风险事故的应急处理和预警预报提供科学支撑。文中引用的大量学术成果文献(每位第一作者优选不超过3篇)显示,经过70年的发展,中国物理海洋学研究培养了一支实力雄厚的科研队伍,这是最宝贵的成果。这支队伍必将成为中国物理海洋学研究攀登新高峰的主力军
气体、溶液中的非电解质与电解质在多孔颗粒内扩散的对比研究
为探明孔隙结构,扩散组分特性以及由这两者决定的扩散机理和扩散组分与孔壁之间的相互作用对有效扩散系数的影响,本文选定气体、溶液中的非电解质和电解质这三类性质相差较大的体系在相同的多孔颗粒内的扩散进行对比研究,目的在于阐明有效扩散系数,特别是曲折因子对孔隙结构和扩散组分特性等因素的依赖关系,为有效扩散系数的估算和预测打下基础。考察由模拟浸取化学反应得出曲折因子的反常高数值是否正确,对模型拟合值的真伪作出判断。在深入研究电解质溶液中扩散规律的基础上,建立混合电解质溶液在多孔颗粒内扩散的数学模型,对混合电解质在孔隙内的扩散问题提供较为严格的处理方法
多孔铁矿石球团还原动力学及其数学模型
孔隙性固体与气体的反应是一类重要反应。多孔铁矿石球团的孔隙特性及反应的多级性,使得还原反应非常复杂并且具有一定的代表性,因此,进行还原动力学的研究并建立还原过程的数学模型具有重要意义。本文通过添加锯末,球团焙烧获得了不同孔隙度的球团;通过观察还原球团样品剖面,论证了多孔球团还原进行的型式;通过控制还原气氛,实现铁矿石球团的逐段还原,求出了各阶段的反应速度常数及反应活化能,并得到了有效扩散系数对孔隙度的函数关系。由此,研究了孔隙度对铁矿石球团还原性能及还原反应进行方式的影响。系统研究了单界面未反应核模型,三界面模型,两阶段模型,微颗粒模型,多级区域反应模型,具有变结构参数的多级区域反应模型和多阶段反应模型等七个模型,并编制了求解模型的计算机程序及用单纯形法进行模型参数优化程序。通过将模型结果与实验结果的比较,研究了各模型对于多孔铁矿石球团还原的适用性及各模型之间的联系与适用条件。此外,本文还研究了还原过程中球团有关结构参数的变化规律,说明了考虑固相结构参数变化的重要性,提出了具有变结构参数的多阶段反应模型
Analysis and Design of Official Document Management System for a Fire Department
随着网络技术和信息技术给办公领域带来了一场革命。实现无纸化、自动化办公方式的革命,对办公模式和生活模式都面临着巨大挑战,公文管理是这一场革命的一部分,实施公文管理自动化是一项繁杂的系统工程。目前某消防部队公文管理工作还没有系统化,急需开发一套适合某消防部队的公文管理系统。 本文的主要研究内容包括业务分析、功能分析和系统设计,功能模块包括收发文管理、公文档案管理、公文查阅管理、基础信息管理和系统管理五大功能;然后给出了系统设计,总体设计给出了系统设计原则和C/S体系结构设计,模块设计主要给出了收发文管理、公文档案管理、公文查阅管理、基础信息管理和系统管理五大功能模块的设计,数据库设计给出了数据...Along with the network technology and information technology has brought a revolution to office areas. Revolution in the way to achieve paperless, office automation, the work mode and life mode are facing huge challenges, document management is that part of a revolution, the implementation of document management automation is a complex system engineering. There is currently no systematic document ...学位:工程硕士院系专业:软件学院_工程硕士(软件工程)学号:X201223089
气体、溶液中的非电解质和电解质在多孔颗粒内扩散的对比研究
实验测量了气体、溶液中的非电解质以及电解质三类性质相差较大的体系在相同的多孔颗粒内(孔隙率0.234~0.632)的有效扩散系数,并计算出曲折因子.探讨了由D_(?)=D_oε/τ定义的曲折因子对孔隙结构和扩散组分特性的依赖关系
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