共查询到20条相似文献，搜索用时 31 毫秒
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An equation of atomization quantity from energy dissipation by hydraulic jump was derived from the dimensional analysis. By applying Gauss diffusion equation, the spray diffusion rule in valley was studied under the condition of continuous linear source and random wind direction. By considering the spray-rain switching process, coagulation, condensation and evaporation of droplets, the air temperature, air relative humidity,spray density and the rainfall intensity in the lower reaches of the linear source were calculated. The 3-D numerical simulation fitted well with prototype monitoring. Finally, the prediction of atomization influence on environments for Xiangjiaba Hydropower Station was conducted. 相似文献
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In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model for risk management of cascade hydropower stations in the medium-term electricity market is presented. The objective function is profit maximization of cascade hydropower stations. In order to avoid the risks of price and inflow uncertainties, two different risk-aversion constraints: a minimum profit constraint and a minimum conditional value-at-risk, are introduced in the model. In addition, the model takes into account technology constraints of the generating units, which includes reservoir flow balance, reservoir capacity limits, water discharge constraints, etc. The model is formulated as a mixed integer nonlinear programming problem. Because the search space of the solution is very large, a genetic algorithm is used to deal with the problem. 相似文献
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提出一种新型的液体除湿系统——超声雾化液体除湿系统,该系统用超声雾化技术取代了传统塔式除湿过程中的填料,避免了由填料带来的溶液耗量大和阻力大的缺点.建立了数学模型来预测在理想条件下液体除湿过程的效率及耗液量.通过对比计算结果和传统塔式除湿的实验数据,发现后者的溶液耗量远大于理想情况下的耗量.另外,在提出的系统中除湿过程发生在通过超声作用产生的微小除湿剂液滴表面,等量的除湿剂能够产生更大的反应表面积;整个新系统中没有喷嘴和溶液泵,系统阻力和能耗相应降低.因此,该方法比塔式除湿方式更接近于理想情况. 相似文献
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基于鞍山市2015年4月2日～26日的空气质量指数数据,将其看为时间序列。通过对其平稳性、自相关和偏相关性的分析,建立了鞍山市空气质量预测ARMA模型。通过实际数据进行预测,并检验模型的精准性。结果表明ARMA模型能收到较好预测效果。 相似文献
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为了在智慧学习环境下实现自适应情感交互,文章首先构建了基于学习者情感的学习画面情感自适应调整模型,并依托此模型开发了原型系统。随后,文章以济南市X中学的98名学生为研究对象,采用准实验研究法,通过学习者情感所占比例分析和问卷数据统计分析,验证了文章提出的假设成立,即智慧学习环境下学习画面情感自适应调整能够提高学习过程中学习者积极情感所占的比例,并能激发学习者的学习兴趣。在智慧学习环境下自适应调整学习画面情感,为解决智慧学习环境情感层面的自适应交互问题提供了新的思路与方法。 相似文献
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宋亚林 《洛阳工业高等专科学校学报》2004,14(4):17-17,35
介绍一种快速获得新型产品零件的方法。以已有的零件或模型为样件，进行CT扫描，获得三维数据，根据用户的需要通过反求工程来完成新型零件的曲面重构、实体造型。结合快速成型制造技术，快速制造出所需零件或其原型。 相似文献
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工程图学CDIO立体动态教学平台的探索 总被引：1，自引：0，他引：1
分析了工程图学构建CDIO立体动态教学平台的优势，充分利用图学课程天时、地利人合的客观条件，提出实施延长实践教学环节具体方法和内容，加重夯实实践教学层面，践行工程图学CDIO立体动态教学模式。实验证明，该教学模式对于启发与培养大学生实际动手能力和创造性都是十分有效的，并将为后续专业课程的学习、毕业设计，甚至为以后的工程与科研工作奠定良好的基础。 相似文献
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为了提高园林三维景观绿化廊道空间规划能力,需要进行空间可视化分割,提出基于锐化模板匹配的园林三维景观绿化廊道空间可视化分割方法,构建园林三维景观绿化廊道视觉图像的稀疏表示模型,采用分块模板匹配方法进行园林三维景观绿化廊道视觉图像的边缘轮廓特征分解,提取园林三维景观绿化廊道视觉分布特征量,结合锐化模板特征匹配的方法进行园林三维景观绿化廊道空间区域重构,建立园林三维景观绿化廊道空间三维视景仿真模型,采用可视化的视觉重构和特征提取方法,进行园林三维景观绿化廊道空间可视化分割。仿真结果表明,采用该方法进行园林三维景观绿化廊道空间可视化分割的自适应性较好,特征分辨能力较强,提高园林三维景观绿化廊道的设计效果。 相似文献
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某型试制中的分体空调室外机长期可靠性运行后的配管出现裂纹,且振动较大。利用ANSYS软件建立了压缩机一配管系统的虚拟样机,通过实验确定了压缩机的激励输出．对施加了压缩机等效载荷的系统进行了动力学分析。根据分析结果对系统的管路进行了改进,仿真分析和实验结果都取得了良好的效果。 相似文献
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This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of motion are solved by using the HilberHughes-Taylor (HHT) time integration method. Firstly, the static damage response analysis of the hydropower station is conducted due to high tensile stress resulting from large water head and diameter of an inlet pipe. Then, on the basis of static simulation, the dynamic damage analysis of hydropower house subjected to earthquake motion is simulated. Numerical results show that under large water head and diameter of an inlet pipe of the project, the damages are mainly located near the top of the spiral case from the inlet section to the 0° section; under combined loadings of static loads and earthquake, the damages of the concrete surrounding the spiral case increase insignificantly; however, some damages occur on the side walls of the main powerhouse. 相似文献
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随着小水电的迅速发展,建立以计算机监控为基础的综合自动化系统已经成为小型水电站自身生存和发展的需要。介绍了以计算机监控为主,常规控制为辅的监控模式和分层分布式监控系统结构进行总体设计的综合自动化系统,并列举了综合自动化系统在小型水电站中应用的一个实例。 相似文献
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Solar energy is a natural resource which can be harnessed to provide clean electricity for hydrogen production systems. However, this technology is not widely used because of control issues, particularly for hydrogen refuelling stations. At present, direct or DC-DC converter couplings are the most common system configurations for hydrogen refuelling stations. However, these system configurations are costly and suffer from gas shortage at hydrogen refuelling stations. Furthermore, the hydrogen produced by such system configurations varies considerably depending on the levels of solar radiation. In order to address these issues, a new system configuration is proposed, incorporating the feedback signal of the storage level in the control system. The photo- voltaic （PV） system, electrolyzer, and storage tank are integrated with a fuzzy logic controller （FLC） to determine the backup current compensation for electrolyzer operation in order to obtain the minimum power required for hydrogen production. The proposed FLC is constructed with three input variables which are the PV current, hydrogen storage level, and the battery state of charge. The rules-based fuzzy inference process is based on the proposed configuration which combines the advantages of direct and DC-DC converter coupling configurations. The simulation results show that the proposed configuration offers better adapta- bility to variable radiation conditions compared to other methods. This gives a more promising option for ensuring the adequacy of hydrogen supply at hydrogen refuelling stations. 相似文献
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A GIS-based approach for estimating spatial distribution of seasonal temperature in Zhejiang Province,China 总被引：2，自引：0，他引：2
LI Jun HUANG Jing-feng WANG Xiu-zhen 《浙江大学学报(A卷英文版)》2006,7(4):647-656
INTRODUCTION Spatial distribution estimates of meteorological data are becoming increasing important as inputs to spatially explicit landscape, regional, and global models. Interpolation is a common method translating for estimated spatial distribution of meteorological data that come from distantly scattered meteorologi- cal stations into raster data, which has benefits of simplicity and convenience. The choice of spatial interpolator is especially important in mountainous areas where dat… 相似文献
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补偿网络是无线电能传输系统中的重要组成部分,可用于提高电能传输的效率、输出功率及稳定性。在对TS-S型补偿网络建模及其参数化设计分析的基础上,采用算例验证TS-S型补偿网络模型的定频谐振、恒定电压增益和高效率特性,通过实验验证相关推论及方法。结果表明,样机电压输出稳定,在耦合系数为0.2时的效率峰值达到90%。 相似文献
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大理岩为碳酸（盐）岩,属易溶岩类,其分布与成因、溶蚀特征及对工程的影响等,系水电站工程勘察论证的重要内容。以某非碳酸盐变质岩区大理岩为例,利用工程勘察取得的资料,在其所处地质环境基础上,分析其分布与成因、溶蚀特征等,并简要阐述其溶蚀对拟建工程产生的影响。 相似文献
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朱铨 《福建工程学院学报》2016,(1):71-75
根据实时交通大数据处理的具体需求,提出实时交通大数据处理云平台的逻辑体系结构,分别从IaaS层、中间件层以及应用层探讨实现云平台动态弹性扩展的关键技术以及仍有待解决的关键问题。并搭建实时交通大数据处理云平台的原型系统,提出实时交通大数据处理云平台资源调度策略。实验结果表明云平台的动态弹性扩展特性可满足实时交通大数据处理的性能需求。 相似文献
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基于数据空间的网格数据管理 总被引：1，自引：0，他引：1
为了更好地管理和应用数据网格中大量分布异构的数据,在对网格技术发展现状进行深入研究基础上,提出基于数据空间概念的网格数据的管理架构.在此基础上,实现了一个网格数据空间管理原型系统,系统中将现有的一些数据空间技术如数据模型iDM、查询语言iTrails等与网格数据访问中间件OGSA-DAI相结合,使用OGSA-DAI工作流来完成数据空间管理系统的数据访问、抽取、数据索引、服务管理和查询回复等一系列工作.实验表明数据空间管理机制在网格环境下是可行的,数据空间管理系统屏蔽了网格数据的分布性和异构性,且能够适应网格数据动态特性,因此满足了对网格数据的管理要求.所提出的网格数据空间架构为网格数据管理提出了新的方法. 相似文献
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On the basis of the current sheet model, a new analytical solution for permanent magnet （PM） bearings is developed. Compared with analytical methods based on the coupling energy model and the magnetic dipole model, the proposed one is more physically intuitive and convenient for engineering designers. According to the analytical model, the thrust characteristics of a novel PM thrust bearing is studied and verified by finite element analysis （FEA）. In the proposed thrust bearing configuration, the rotor is composed of stacked PM tings with alternative axial magnetization directions, and the stator with alternative radial magnetization directions while copper rings are used to separate adjacent PM rings. A prototype PM thrust bearing with the proposed configuration is designed and fabricated. The performances of the PM thrust beating are experimentally validated. It is shown that the calculation accuracy of the presented analytical solution is satisfying. 相似文献
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Analysis of Network Traffic with Extreme Value Theory 总被引：1，自引：0，他引：1
Withincreasingdemandofwidebandwidthservicesuchasmultimediaandvideo ,itisverydesirabletore searchondifferenttransporttechniquesforhigh speednetworks.Congestioncontrol,bandwidthassignment ,networkmanagementand performanceevaluationaresomeexamplesthathavebeenresearchedwidely .Asthefoundationoftheseresearchfields ,itisthemostessentialtobuildamodelthatcanaccuratelycharacterizerealnet worktraffic .Hence ,itisalsonecessarytounderstandandanalyzestatisticalpropertiesofthenetworktrafficbecauseitcanindic… 相似文献