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51.
52.
李邦河 《应用泛函分析学报》2006,8(4):295-303
证明了傅立叶超函数和扩充傅立叶超函数可用爱米特热方程的解来表示,且用以表示的解有很良好的性质. 相似文献
53.
A control volume type numerical methodology for the analysis of steady three‐dimensional rotating flows with heat transfer, in both laminar and turbulent conditions, is implemented and experimentally tested. Non‐axisymmetric momentum and heat transfer phenomena are allowed for. Turbulent transport is alternatively represented through three existing versions of the k–ε model that were adjusted to take into account the turbulence anisotropy promoted by rotation, streamline curvature and thermal buoyancy. Their relative performance is evaluated by comparison of calculated local and global heat balances with those obtained through measurements in a laboratory device. A modified version of the Lam and Bremhorst, low Reynolds number model is seen to give the best results. A preliminary analysis focused on the flow structure and the transfer of heat is reported. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
54.
Nusselt number correlations for heat transfer to small spheres in thermal plasma flows 总被引:1,自引:0,他引:1
Seven different equations predicting heat transfer rates to small spheres in plasma flows are examined considering argon and nitrogan as plasma gases from 300 to 21,000 K at 1 atm. For argon there is a general consensus up to 9000 K, beyond which wide deviations in behavior occur. For nitrogen, the seven correlations are in good agreement up to 4000 K, but show substantial deviations beyond this value. Comparisons with the sparsely available experimental data are made for argon from 300 to 17,000 K and for nitrogen up to 5500 K. Disagreement between the various correlations and experiment can exceed one order of magnitude. 相似文献
55.
根据热力学第一定律和理想气体状态方程推导了理想气体的热容量公式,并对理想气体在p-V图上的直线过程和循环过程的温度变化及吸热和放热进行了讨论. 相似文献
56.
Maksimov R. D. Zicans J. Ivanova T. Negreeva S. N. Plume E. 《Mechanics of Composite Materials》2002,38(2):141-148
The results of experimental and theoretical investigations of elastic and thermophysical properties of poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE) blends are presented. Eight types of specimens with different ratios of weight contents of PVC and CPE (PVC/CPE = 100/0, 90/10, 80/20, 60/40, 40/60, 20/80, 10/90, and 0/100) were tested. The effect of blend composition on the elastic constants (tensile and shear modulus) is discussed. The data on the thermal conductivity, thermal diffusivity, and heat capacity of the blends investigated are also presented. 相似文献
57.
The features of interaction of a spherical metallic particle with a rarefied thermal plasma flow due to the presence o charges-electrons and ions in the gaseous phase-are considered. Analytical expressions describing charge, momentum, and energy exchange between the plasma and the particle für the cases of strong and weak Debye screening are obtained. It is illustrated that the efficiency of particle heating in the plasma considerably grows as compared with a hot molecular gas due to participation of electrons and ions in file transfer processes. 相似文献
58.
59.
采用热处理方法提高MEH-PPV单层聚合物有机发光二极管发光性能的研究 总被引:2,自引:1,他引:1
对以MEH-PPV为发光层的单层聚合物有机发光二极管(OLED)器件在最佳条件下进行真空热处理,并用金相显微镜观察施加电压后器件的阴极表面形貌。发现处理后的器件阴极表面的气泡及黑斑明显减少。器件的发光性能显著提高。与未经处理的器件相比,最大相对发光强度提高了一个数量级、启亮电压降低了2.0V,半寿命提高了12.7倍。初步分析表明热处理方法提高器件发光性能的主要原因在于有效地减少了器件在工作过程中由于焦耳热产生的某些气体,从而减少阴极表面气泡及黑斑的出现,另一方面,热处理方法也增强了有机发光层与阴极接触界面的结合力,提高电子注入水平。 相似文献
60.
Fabio Fantozzi Sauro Filippeschi Enrico Maria Latrofa 《Superlattices and Microstructures》2004,35(3-6):339
Upward and downward two-phase heat and mass transfer has been considered in the present paper. The heat and mass transfer with the condenser located below the evaporator has been obtained by inserting an accumulator tank in the liquid line of a loop thermosyphon and enforcing a pressure pulsation. In previous papers these heat transfer devices have been called pulsated two phase thermosyphons (PTPT). A mini PTPT has been experimentally investigated. It has shown a stable periodic heat transfer regime weakly influenced by the position of the condenser with respect to the evaporator. In contrast a classical loop mini thermosyphon (diameter of connecting pipes 4 mm) did not achieve a stable functioning for the investigated level differences between evaporator and condenser lower than 0.37 m. The present study shows that the functioning of a PTPT device does not directly depend on the level difference or the presence of noncondensable gas. In order to obtain a natural circulation in mini or micro loops, a periodically operating heat transfer regime should therefore be considered. 相似文献