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随着中国经济的飞速发展,能源短缺,环境污染等问题日益严重.欧美等发达国家早已开始着手解决这些问题,每年都有大量来自于政府、企业和风险投资的资金用于清洁技术的研究与应用.根据道琼斯数据显示,2007年在清洁技术领域,全球共发生了221项投资案例,投资总额达30亿美元,比2006年增长了43%. 相似文献
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第十七届世界国际氢能大会于2008年6月15日~19日在澳大利亚布里斯班市举行,来自全世界44个国家的600余位代表聚集一堂,讨论当代氧能技术和发展趋势. 相似文献
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The adiabatic film effectiveness η of the counter-inclined film-holes fed by varying internal coolant intake on the turbine vane leading edge model was experimentally investigated. A semi-cylinder model was adopted to model the vane leading edge which was arranged with two-row holes, which located at ±15° on both sides. The four Leading edge model with the combinations of hole-shape(simple holes and laid-back holes) and intake structure(plenum and impingement) were tested under four blowing rati... 相似文献
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一、太阳与太阳能 众所周知,在浩翰的宇宙中有一颗离我们最近的恒星--太阳.现代科学表明太阳距离我们相当遥远,达到1.5亿km,虽然太阳光的传播速度为30万km/s,但我们在地球上所见到的光线已经是8min之前从太阳发出的光线了.太阳的直径为139万km,而地球直径仅为1.27万km,太阳的直径约为地球直径的109倍,其体积则比地球大130多万倍.尽管如此,由于距离遥远,太阳张角仅仅为32′. 相似文献
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WANG Zehui WU Kefeng WANG Ti XIA Liangwei YU Qiang HUANG Ying SUN Hao WEI Guohua GUAN Jingyu YAN Yanfei 《热科学学报(英文版)》2021,30(1):302-312
Under the back-side windy condition,the convection and radiation heat transfer characteristics in an iso-flux upward-facing cylindrical cavity were studied by three-dimensional numerical simulation.The impacts of cavity tilt angle,wind incident angle and wind speed on convection and radiation heat transfer Nusselt number Nuc and Nur were analyzed,and the possible explanations for their impacts were presented.Results show that due to the disturbance of wind,the influence of cavity tilt angle becomes more complicated and is related to wind incident angle and wind speed.The variation of Nuc or Nur with wind incident angle is different for different cavity tilt angles.Despite of the changes of cavity tilt angle or wind incident angle,the Nuc increases with the wind speed while the Nur presents a declination with the increasing of wind speed.Hence,compared with cavity tilt angle and wind incident angle,wind speed may be the dominant factor affecting or controlling the convective and radiation heat transfer of cavity. 相似文献
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太阳能干燥系列讲座(1)太阳能干燥——太阳能热利用中不可忽视的领域 总被引:1,自引:0,他引:1
一物料干燥的能耗与环境污染 干燥作业涉及国民经济的广泛领域,是许多行业不可缺少的工序.在粮食、食品、果品、药材、木材、皮革、橡胶和陶瓷等许多产品的加工处理过程中,干燥作业对产品的质量和成本影响很大. 相似文献
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《节能与环保》编辑部 《节能与环保》2015,(8)
<正>6月30日,当中国政府将《强化应对气候变化行动——中国国家自主贡献》提交给联合国气候变化框架公约秘书处后,全世界都为中国的决定而侧目。中国设定了一个宏大的减排目标,振奋了各国应对气候变暖的神经。潘基文在声明中称赞中国提出的方案为在巴黎气候变化大会上增加动力、增强互信起到了积极推动作用;联合国秘书长副发言人哈克表示,中国提交自主贡献文件,为巴黎气候大会达成新的气候变化协议注入了动力, 相似文献
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户用小型风力发电系统现状与发展(上) 总被引:6,自引:0,他引:6
<中华人民共和国可再生能源法>已于2005年2月28日在全国人大第11届第14次会议上通过,并将于2006年1月1日起施行,该法的颁布和实施,给小型风力发电行业的发展带来希望和光明,也必将大大促进农村能源的发展,户用风力发电产业也将会更上一层楼,前景看好. 相似文献
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Guy Casale 《Journal of Dynamical and Control Systems》2012,18(4):449-454
We present a proof of the fact that the monodromy group of a Liouvillian function is almost solvable. The first proof of this theorem was given by A. Khovanskii. 相似文献
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In previous study, the vertical wind speed extrapolation from measurement station to modern turbine hubs over an open homogenous terrain was considered. It was presented that an assumption of wind shear exponent under different stability conditions was an inaccurate representation of the actual wind climates as the precise knowledge of the site's wind characteristics at different levels and seasons are essential for planning and implementation of a proposed energy project. In this study, the surface-layer wind speed correction at Darling using the WRF modeling with mesoscale terrain corrections is presented. An hourly mesoscale modeled winds at 3 km grid spacing obtained for one month are postprocessed for estimation of local wind speed profiles at 10 and 50 m height AGL. The sensitivity of the modeled winds to surface terrain corrections is investigated using mesoscale topography parameterizations. Furthermore, 6-hourly mesoscale modeled and satellite observed winds as well as measurements from Darling station are utilized for validation of the statistical downscaling method utilized for the postprocessing of the boundary layer winds over land. It is presented that the precision of the mesoscale modeled winds for local wind speed estimates at potential site without historical measurements can be significantly improved. The confidence in the validity of this methodology for local wind speed correction is estimated at 96–98%. 相似文献
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起初的太阳热水工程用不上什么电控装置,系统十分简单,几个手动阀门就解决了所有问题。上水靠手动、循环靠虹吸、供水靠架高、防冻靠停用、凉热靠老天。随着人们对太阳热水系统供水要求的提高和控制技术的发展,才把电磁阀、水泵等电控装置引入到太阳热水系统中来。于是逐渐有了定温上水、温差循环、防冻排空、辅助加热、供水增压、混水调温等自动功能。这明显地提升了太阳热水工程的应用品味,使用户得到了更多的方便和实惠。功能愈是全面的系统,就愈需要配置更多的外部装置来做支撑。 相似文献
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Piwko R. Camm E. Ellis A. Muljadi E. Zavadil R. Walling R. O'Malley M. Irwin G. Saylors S. 《Power and Energy Magazine, IEEE》2009,7(6):26-35
IEEE activities related to wind power and other alternate energy technologies were under the purview of the Enerrgy Development Subcommittee (EDS) of the Energy Development and Power Generation Committee (EDPG) from the 1970s to the early 1990s. As the interest in these topics grew, a working group concerned with renewable resources and energy storage was formed in 1994 with Rama Ramakumar as chair. Subsequently, this working group evolved into two groups, one chaired by Ramakumar dealing with renewable technologies that included wind power and the other focused on distributed generation and energy storage and chaired by John Bzura. At every winter and summer meeting up to 2002 and at the annual General Meetings starting in 2003, the EDS and its two working groups organized panel sessions and numerous technical paper sessions dealing with wind energy, photovoltaics, fuel cells, advanced energy storage technologies, and related topics. These technical areas were nurtured by the EDS and were kept active, viable, and visible to the power engineering community, even during periods when there was little interest in renewable technologies. Participation and interest in these areas--especially in wind power--have grown signifi cantly in the recent past, culminating in the formation of the Wind Power Coordinating Committee (WPCC) in 2005. 相似文献
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Jarosław Milewski Marcin WołowiczAndrzej Miller Rafał Bernat 《International Journal of Hydrogen Energy》2013
The mathematical model of the Molten Carbonate Fuel Cell (MCFC) is presented. The new approach for modeling the voltage of MCFC is proposed. Electrochemical, thermal, electrical and flow parameters are collected in the 0-D mathematical model. The aim was to combine all cell working conditions in as a low number of factors as possible and to have the factors relatively easy to determine. A validation process for various experimental data was made and adequate results are shown. The presented model was validated for various fuel mixtures in relatively wide ranges of parameters. A distinction is made between the “design-point” and “off-design operation”. 相似文献
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A technique was invented to circumvent computational singularity at a radial center of cylindrical and spherical coordinate systems. The idea is as follows. The radial velocity at a center is given by the average of adjacent circumferential directional velocity components located at ± 0.5π rod. Sample computations are presented for natural convection in a vertical cylinder with two different thermal boundary conditions. Those velocity profiles through a cylinder center are smoothly represented. 相似文献
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对一台被动预燃室增压直喷汽油机的燃烧过程进行了三维数值模拟分析,研究了预燃室的不同设计参数如预燃室容积、射流孔数量、射流孔直径、射流孔结构等对当量燃烧时燃烧特性的影响。结果表明,预燃室射流点火优于常规火花塞点火的重要原因是主燃烧室内着火点增多,同时点火后预燃室内产生的高速冲击射流会提升主燃室内的湍流强度,从而加快湍流火焰的传播。在2 000 r/min转速和1.2 MPa平均指示有效压力工况下预燃室发动机的50%燃烧角相对火花塞发动机提前约8.5°。不同结构参数的预燃室模拟分析表明燃烧初期预燃室喷入主燃室射流的动量越大,对主燃室湍流强度的提升效果会越大,燃烧相位也会更优,在上述工况下不同结构预燃室50%燃烧角的差异最高可达约5.8°。变更预燃室结构造成的燃烧相位差异主要体现在燃烧前中期,随着转速和负荷升高,该差异有降低的趋势。 相似文献