共查询到20条相似文献,搜索用时 15 毫秒
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C. Lertsatitthanakorn J. Jamradloedluk M. Rungsiyopas 《Journal of Electronic Materials》2013,42(7):2119-2126
In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction. 相似文献
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《Components and Packaging Technologies, IEEE Transactions on》2009,32(1):53-62
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Raleva K. Vasileska D. Goodnick S.M. Nedjalkov M. 《Electron Devices, IEEE Transactions on》2008,55(6):1306-1316
In order to investigate the role of self-heating effects on the electrical characteristics of nanoscale devices, we implemented a 2D Monte Carlo device simulator that includes the self-consistent solution of the energy balance equations for both acoustic and optical phonons. The acoustic and optical phonon temperatures are fed back into the electron transport solver through temperature-dependent scattering tables. The electrothermal device simulator was used in the study of different generations of nanoscale fully depleted silicon-on-insulator devices that are either already in production or will be fabricated in the next five to ten years. We find less degradation due to self-heating in very short channel device structures due to the increasing role of nonstationary velocity-overshoot effects which are less sensitive to the local temperature. 相似文献
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In video applications, the storage requirement is considerably large and hence they require large amount of network resources for their transmission. For transmitting the videos through a physical channel, there are two types of channelization-constant bandwidth and variable bandwidth channelization. It has been reported that using variable bandwidth channelization the buffer storage requirement is less than that of constant bandwidth channelization. Therefore, using variable bandwidth channelization a stochastic model is proposed for estimating the buffer storage so that the continuous delivery of the video data can be provided to the users. 相似文献
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Modeling Communication Networks With Hybrid Systems 总被引:1,自引:0,他引:1
Junsoo Lee Bohacek S. Hespanha J.P. Obraczka K. 《Networking, IEEE/ACM Transactions on》2007,15(3):630-643
This paper introduces a general hybrid systems framework to model the flow of traffic in communication networks. The proposed models use averaging to continuously approximate discrete variables such as congestion window and queue size. Because averaging occurs over short time intervals, discrete events such as the occurrences of a drop and the consequent reaction by congestion control can still be captured. This modeling framework, thus, fills a gap between purely packet-level and fluid-based models, faithfully capturing the dynamics of transient phenomena and yet providing significant flexibility in modeling various congestion control mechanisms, different queueing policies, multicast transmission, etc. The modeling framework is validated by comparing simulations of the hybrid models against packet-level simulations. It is shown that the probability density functions produced by the ns-2 network simulator match closely those obtained with hybrid models. Moreover, a complexity analysis supports the observation that in networks with large per-flow bandwidths, simulations using hybrid models require significantly less computational resources than ns-2 simulations. Tools developed to automate the generation and simulation of hybrid systems models are also presented. Their use is showcased in a study, which simulates TCP flows with different roundtrip times over the Abilene backbone. 相似文献
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Modeling and Simulation of Electric and Hybrid Vehicles 总被引:1,自引:0,他引:1
Gao D. W. Mi C. Emadi A. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2007,95(4):729-745
This paper discusses the need for modeling and simulation of electric and hybrid vehicles. Different modeling methods such as physics-based Resistive Companion Form technique and Bond Graph method are presented with powertrain component and system modeling examples. The modeling and simulation capabilities of existing tools such as Powertrain System Analysis Toolkit (PSAT), ADvanced VehIcle SimulatOR (ADVISOR), PSIM, and Virtual Test Bed are demonstrated through application examples. Since power electronics is indispensable in hybrid vehicles, the issue of numerical oscillations in dynamic simulations involving power electronics is briefly addressed 相似文献
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基于SMP集群的MPI+OpenMP混合编程模型及有效实现 总被引:11,自引:1,他引:11
SMP集群混合了两个内存模型:每个节点是一个共享存储的多处理器,而节点间使用分布存储。这一多级体系结构引起了编程模型和性能方面的问题。文章讨论了MPI+OpenMP混合编程模型的性能和不同的实现方法,提出了多粒度MPI+OpenMP混合编程方法。建立了对称三对角特征问题的多粒度混合并行算法.并在深腾6800超级计算机上同纯MPI算法作了性能方面的比较。结果表明,该混合并行算法具有更好的扩展性和加速比。 相似文献
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Recent experiments demonstrated a very high thermal conductivity in graphite nanosheet (GNS)/epoxy nanocomposites; however,
theoretical analysis is lacking. In this letter, an effective medium model has been used to analyze the effective thermal
conductivity of the GNS/polymer nanocomposites and has shown good validity. Strong influences of the aspect ratio and the
orientation of the GNS are evident. As expected, interfacial thermal resistance still plays a role in determining the overall
thermal transport in the GNS/polymer nanocomposites. In comparison with the interfacial thermal resistance between carbon
nanotubes and polymers, the interfacial thermal resistance between GNS and polymers is about one order of magnitude lower,
the reason for which is discussed. 相似文献
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Zhuo Yang Xiao-Hao Liu Xiang-Xi He Wei-Hong Lai Li Li Yun Qiao Shu-Lei Chou Minghong Wu 《Advanced functional materials》2021,31(8):2006457
Growing demands on energy storage devices have inspired a tremendous amount of research on rechargeable batteries. Future generations of rechargeable batteries are required to have high energy density, long lifespan, low cost, high safety, low environmental impact, and wide commercial affordability. To achieve these goals, significant efforts are underway to focus on electrolyte chemistry, electrode engineering, and new designs for energy storage systems. Herein, a comprehensive overview of an innovative sodium-based hybrid metal-ion battery (HMIBs) for advanced next-generation energy storage is presented. Recent advances on sodium-based HMIBs from the development of reformulated or novel materials associated with Na+ ions and other metal ions (such as Li+, K+, Mg2+, Zn2+, etc.), are summarized in this work. Daniell cell and “rocking-chair” type batteries are covered. Finally, the current challenges and future remedies in terms of the design and fabrication of new electrolytes, cathodes, and anodes for advanced HMIBs are discussed in this report. 相似文献
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随着高速PCB设计的数量不断增加,对确保布线、信号完整性和热设计要求造成了很大的困难。为了能够应付这一现象,美国CiscoSystems公司已经推出了一款可以进行温度预测设计流量的产品,它能够极大的改善电路设计师和机械设计师之间的共同设计协调性。设计师们可以通过PCB设计软件进行相关信息的交流,以有助于热分析工作的开展。 相似文献
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基于先进逻辑CMOS工艺平台,构建了集成电路热耦合模型,为后端金属线电迁移预测提供更精确的温度变化和分布信息。在建模过程中,为了提高建模和仿真效率,对金属线网络和晶体管有源区进行简化,并用热传输比率对热耦合进行表征。考虑到晶体管参数、金属线走向、金属线之间相对位置对热传输比率的影响,模型中引入相关因子对热传输比率做进一步修正。最后,将该热传输模型嵌入到商用仿真软件中。结果表明,热传输比率(即温度)的仿真值与基于工艺平台流片的实测值吻合良好,验证了模型的准确性。 相似文献
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为了解决多路信号并行混合采集存储的问题,文中设计了一种以FPGA为控制芯片的多路并行采集存储系统。该系统选用XC6SLX163CSG324I为主控芯片,设计包括数据采集接收模块、数据存储模块、数据回读模块。数据接收模块包括16路模拟量数据、导引头(DYT)数据、脉冲编码调制(PCM)数据和控制命令数据。该系统充分利用FPGA可重构的优势,对内部资源合理利用,降低了硬件资源开销,对所接收数据进行多路并行采集存储;利用握手原则,减少了数据的丢失。实验结果表明,该系统存储速率最高可达25 Mbyte/s,且备用口回读数据时,帧计数连续,该系统准确性较高。 相似文献
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提出了采用耳机热效应模型来预测耳机声圈阻值在工作中的变化,从分析耳机工作中的热传递和蓄热机制出发构建了耳机的热效应模型,分频段对模型作了适当简化并确定出模型参数。中频和高频模型能很好地预测声圈阻值的变化,据此补偿耳机响应,改善耳机的听觉效果。 相似文献