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浅谈区域噪声质量评价 总被引:4,自引:0,他引:4
一、前言环境影响评价的概念首先由美国于1969年提出,随后瑞典,澳大利亚,法国,新西兰,加拿大等国陆续推行,环境影响评价内容包括:大气、地面水,地下水,土壤,噪声,振动,恶臭,电波干扰,生态以及人群健康等,其中噪声评价是个不可缺少的内容之一,区域噪声评价是内容较广泛的噪声评价,其中包括工厂装置噪声,交通噪声,建筑施工噪声,社会生活噪声等,其中交通噪声又可分为道路交通噪声,铁路噪声,飞机噪声,另外还有正常,非正常的放空噪声。就对环境影响而言,长期的,持久性的和短期的,突发性的噪声,本区域噪声主要为工厂… 相似文献
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布谷孜大桥地基与基础地震反应分析 总被引:3,自引:0,他引:3
本文对布谷孜大桥桩,土,上部结构的共同作用进行地震反应分析,对自由场体系在基岩处输入天津宁河波,分别按7,8,9度抗震设防,分析了各层土的地震响应,考虑桩,土,上部结构共同作用,采用二维和三维模型,分别按7,8,9度抗震设施,分析了桩,土,上部结构的地震响应,并对不同桩长及土体加固进行了计算与分析。 相似文献
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激光辐照制备搪瓷涂层 总被引:4,自引:0,他引:4
激光辐照制备的热衷瓷涂层表面粗糙,与金属基材结合牢固,一般由Si,Al,Na,K,B,F,O等元素组成,在激光辐照过程中K,Na明显地挥发,从而在涂层中的含量明显减少,Co,Ni主要分布在界面附近:Fe元素也由基材进入涂层,呈梯度状分布,在界面过渡区含量很高,在涂层内含量很低,搪瓷涂层的形成与激光辐照参数,特别与激光功率间存在极为密切的关系,只有选用合理的参数,才能制得搪瓷涂层。 相似文献
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日前,青岛衡器测试中心受国家技术监督局委托,对”全国对家企业的ACS-15型电子计价秤进行了1997年第2季度监督抽查,抽查结果,合格18家,不合格3家,合格率为85%,质量比往年有明显提高。这次抽查的产品可分为两类,一类是80年代的产品,其特征外观一般,体积较大,结构复杂,元器件多,成本高。另一类是叨年代的新产品,其特征外观造型讲究,体积轻便,结构简单,集成化程度高,调试简便,成本低,实际上是加年代的换代产品。第一类5个产品合格3个,第二类16个产品,合格15个,合格率分别为m%和94%。这一结果表明,国内电子计价秤… 相似文献
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三、塑料包装弃物回收利用 塑料包装材料具有重量轻,强度大,抗冲击性好,透明,防潮,美观,化学性能稳定,韧性好且防腐蚀等优点,在包装领域广泛地取代了大量的金属,木材,纸张,玻璃,皮革等,因此,塑料包装对减轻我国的资源,能源压力起到了不可替代的作用,但是,塑料包装材料一个致命的弱点,即其自然降解时间长,有的长达100年以上。 相似文献
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..........................................……曾经的我,青春单纯,为了我那紫色梦想。有缘与你。懂我的你,只为我人生的缤纷,将绚丽的七彩色为我装扮,不曾留下你我共同的担心:刀丝、压印……也因为你的关心,你的体贴,为我穿上昂贵的AL,N丫,使我更加成熟。懂你的我,哪怕经受室温、高温的考验,也留不下通洞,白点的遗憾。人生几何,你的培育让我健康成长,时光飞逝,没有不散的宴席,面对现实,尊重你我共同的选择,临行前,你告诉我,不必伤心、哭泣,好男儿志在西方。带着你的愿望,拌着我的希望,踏上我的不归路,纵然到天… 相似文献
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小型中央空调同组以其性能可能,价格达中,安装方便,使用灵活,占用空间小,操作简单,维护费用低等特点,较好的满足了市场的需求,受到了用户的青睐,在住宅,别墅,餐厅,商场,写字间等外采用愈来愈多。本文分析了家用空调器的缺点,解释了小型中央空调机组的由来,说明了小型中央空调机组的特点和分类,阐述了小型中央空调机组的发展前景,为小型中央空调机组的广泛使用奠定了基础。 相似文献
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Heat sources for heat pumps in buildings as well as in industry are discussed. Furthermore, some environmental aspects concerning choice of heat source are highlighted. Only systems for heat pumping are included, i.e. air-conditioning types which can also partly work as heat pumps are excluded. Recent heat pump installations in Sweden are mainly in small systems. Ambient air, exhaust air, soil and rock are the most common heat source types. Data on COP, investment costs, working fluids, present Swedish market etc. for these types of heat sources are given. Data on industrial heat pump installations in some countries and distribution of these according to heat pump type and industry sector as well as heat source temperatures are reported. Process integration aspects when choosing heat source size and temperature are also discussed as well as the relation between these parameters and the choice of heat pump type. Finally, the influence on the economy of the heat source temperature is presented. The cost-effectiveness of heat pumps for reducing CO2 emissions compared with other heating technologies is discussed. The main results are: (1) heat pumps can in many cases in the future contribute to a reduction of CO2; (2) there is a rather big difference, for larger systems a major difference, between the water-based and the ambient air-based heat pumps in terms of efficient reduction of greenhouse gas emissions. 相似文献
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Methods and Feasibility of Residual Stress Analysis by High-Energy Synchrotron Radiation in Transmission Geometry Using a White Beam 总被引:1,自引:0,他引:1
A. Pyzalla 《Journal of Nondestructive Evaluation》2000,19(1):21-31
White high-energy synchrotron radiation has recently been introduced as a new tool for the analysis of the triaxial residual stress state in the bulk of metals, ceramics, and composite materials. First, the set-up of an experiment is presented. Then, based upon theoretical considerations and experimental data, the parameters of the setup and the possibilities as well as limits of residual stress analysis by white high-energy synchrotron radiation are discussed. The resolution in energy as well as the spatial resolution achievable are shown and the implications of the material investigated such as coarse grains and texture are studied. Examples for simultaneous texture and residual stress analyses are presented. 相似文献
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介绍了采用空气作工质的空气压缩制冷系统和空气除湿制冷系统流程及其应用现状,分析了两种制冷系统在普冷领域内的应用前景及有待解决的关键技术,并对两种制冷系统进行了总结和比较。 相似文献
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Mahajan VN Dai GM 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(9):2994-3016
Zernike circle polynomials are in widespread use for wavefront analysis because of their orthogonality over a circular pupil and their representation of balanced classical aberrations. In recent papers, we derived closed-form polynomials that are orthonormal over a hexagonal pupil, such as the hexagonal segments of a large mirror. We extend our work to elliptical, rectangular, and square pupils. Using the circle polynomials as the basis functions for their orthogonalization over such pupils, we derive closed-form polynomials that are orthonormal over them. These polynomials are unique in that they are not only orthogonal across such pupils, but also represent balanced classical aberrations, just as the Zernike circle polynomials are unique in these respects for circular pupils. The polynomials are given in terms of the circle polynomials as well as in polar and Cartesian coordinates. Relationships between the orthonormal coefficients and the corresponding Zernike coefficients for a given pupil are also obtained. The orthonormal polynomials for a one-dimensional slit pupil are obtained as a limiting case of a rectangular pupil. 相似文献
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S. A. Esenwein S. Esenwein C.‐H. Hartwig G. Herr G. Muhr 《Materialwissenschaft und Werkstofftechnik》2004,35(4):178-185
Clinical applications of porous biomaterials in bone During therapy of bone defects and lesions it often exists the necessity to treat larger defects. While doing so porous biomaterials are frequently used as an alternative to autologeous bone in the field of implantology, traumatology and orthopaedic surgery with good clinical results. In contrast to autologeous cancellous bone grafts they are of an almost unlimited availability and are not afflicted with the problem of donor morbidity. In order to accelerate the quantity and quality of the newly formed bone and thus to enable the reconstruction of a defect, different biomaterials are used as bone substitutes. These are materials which are able to interact with biological systems, and mostly synthetic porous tricalciumphophates and hydroxyapatite ceramics as well as processed allografts are used. As an additional possibility of clinical application surface coating of implants with porous biomaterials and bone‐forming growth factors comes into consideration. In the presented work an overview of the clinical application possibilities of porous biomaterials in bone as well as an outlook on future developments is supposed to be given. 相似文献
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介绍了垂直沟道器件的常见结构和工艺,分析了垂直沟道器件的最新进展以及垂直沟道器件制作工艺中的最新技术,详细讨论了垂直沟道器件的性能,并分析了垂直沟道器件的优点以及存在的问题。 相似文献
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Aníbal J. Valido 《工程优选》2013,45(5):553-560
This paper applies the formulation and the finite element analysis and sensitivity analysis model developed in a companion paper to the optimal design of various geometrically nonlinear composite laminate beam structures. The element design sensitivities are imbedded in the finite element code and the global sensitivities are interfacing the analysis with a nonlinear programming optimizer. Laminate thickness and lamina orientations are considered as design variables. Mass, stiffness and deflection are used as objectives or combined as multiobjective functions. The nonlinear critical load or the Tsai-Hill stress failure index, are used as constraints. Postcritical domain behavior allows the advantageous substitution of the critical load constraint by a displacement constraint. 相似文献