Thermal performance of flat vapor chamber heat spreader

Experiments were performed to examine the spreading thermal resistance of centrally positioned heat sources and the thermal performance of a water charged, gravity assisted flat vapor chamber to be used for electronic cooling. Parametric studies including different heat fluxes and operating temperatures were conducted, and the effect of the relevant parameters on the cooling performance in terms of the spreading resistance was presented and discussed. The present vapor chamber heat spreader showed a heat removal capacity of 220 W/cm² with a thermal spreading resistance of 0.2 °C/W.     

基于三(8-羟基喹啉)铝的紫外增强薄膜研究

为了提高硅基成像器件的紫外响应,本文通过对Alq3发光机理与光致发光特性的研究,用真空蒸镀的方法制备出了基于Alq3的有机金属薄膜.通过测量Alq3薄膜的透过率、光致发光光谱和激发光谱,发现Alq3薄膜在可见波段有很好的透过性,用紫外光激发会产生较强的绿光(中心波长位于510 nm),且激发光谱宽(250～425 nm).结论表明Alq3薄膜的发射光谱能够与传统硅基成像器件的响应光谱匹配,是一种符合实际要求的紫外增强薄膜.     

Numerical study on the evaporative and condensational dissipation of phosphoric acid in PAFC

In phosphoric acid fuel cell (PAFC) stack, reduction of the phosphoric acid that is impregnated in the cell is a major factor to restrict the operating life. In this paper, the phosphoric acid reduction by the evaporative and condensational dissipation was evaluated by numerical analysis. The calculations that include the behavior of heat transfer, gas flow, and evaporation and condensation of phosphoric acid were conducted for the model cell with conditions that correspond to an on site stack. The phosphoric acid was considered as a composite of phosphorus pentoxide and water, and the evaporation and condensation rates were derived based on the nucleation theory for a two components system. The phosphoric acid distributions in the vapor phase and liquid phase at the process gas and electrode were calculated for the duration of 3300 h, and as a result of those, the exhausting and remaining amount of phosphoric acid for the cell were evaluated. The analysis results were compared with the experimental results for the model cell.     

非能动安全壳冷却系统CFD冷凝和蒸发模型研究

利用计算流体动力学(CFD)程序平台CASTEM,开发非能动安全壳冷却系统的冷凝、蒸发模型.冷凝模型中分别采用Buleev和k-ε两种湍流模型,蒸发模型采用了GAiello(2009)发展的液膜蒸发模型.试验验证分析表明,计算值与试验值吻合较好,所建立的冷凝、蒸发模型能较好地模拟非能动安全壳冷却系统在稳态下的传热传质特性.     

氧化铝生产蒸发系统分析

根据实际蒸发系统流程提出了相关的算法，对蒸发系统各因素之间的关系进行了数值模拟，详细分析了进料量，结疤厚度，真空度等因素对蒸发系统的影响，得出了与现场生产数据相一致的结果。     

Evaporation-induced pattern formation in polymer films via secondary phase separation

The ordered necklace-like or cellular pattern formation has been investigated for ternary polymer solutions in which primary and secondary phase separations were induced by the solvent evaporation. The patterns consisted of regular droplet arrays of various diameters, which arose in the pre-existing polymer phases via the secondary phase separation. The pattern formation was enhanced with increasing air velocity and ambient humidity, while it was suppressed with decreasing initial film thickness. The regular pattern was independent of surface wettability of the solid substrate. We ascribe the morphology change to the evaporation-induced surface tension driven convection, which re-arranged the droplet distributions from disordered to flow-induced ordered patterns.     

Advances in Direct Contact Evaporator Design

Direct contact evaporators are nonisothermal bubble columns where a hot gas, usually obtained by combustion, is used to heat and vaporize the solvent of a given solution that needs to be concentrated. The design of such equipment has been relied on experimental data or on a simplified method that assumes that the gas leaves the evaporator at equilibrium with the liquid phase, giving no information about the necessary bubbling height to attain such equilibrium conditions. Recent advances in the heat and mass transfer processes during the formation and ascension of superheated bubbles together with simple mass and energy balances in the liquid phase and gas distributor system were used to develop a more detailed design procedure. The accuracy of both design procedures are compared to available experimental data in a direct contact evaporator operating in semibatch mode. The new design method agreed well with the experimental data.     

DRYING OF WASTE SLUDGES IN A FLUIDIZED BED DRYER WITH A MIXER

Sludge wastes are a very attractive source of many valuable compounds such as nitrogen, phosphorus and organic matter. One of the interesting methods of sludge utilization is dewatering and drying. In this paper some problems of drying of two types of sludge wastes of different form and origin are presented. One of the sludges—a brewery by-product— contains spent grain suspension of brewer's yeast and diatomaceous earth. The second one is a by-product of a biotechnological process which contains mainly lime, protein, many microelements and some microorganisms. Moisture content of both sludges is about 65-70% w/w. The laboratory experiments of sludge drying in the fluidized bed dryer with a mixer, fluidized bed hydrodynamics, and the effects and advantages of sludge drying are shown.     

M型扩散阴极用新型含锶低蒸散发射活性材料

聚焦真空器件用M型(Magic)阴极的蒸发性能,采用共沉淀法将Sr元素掺入阴极发射活性材料中,研究发射活性材料成分差异对阴极蒸发性能及发射性能的影响。研究结果显示,相同的制备及测试条件下,浸渍了新型含锶发射活性材料的M型阴极的蒸发速率显著下降,两种新型发射活性材料(AM1#和AM2#)浸渍的阴极样品的蒸发率在1060℃测试时,较常规阴极的蒸发率分别下降了49.95%和71.87%;在1100℃测试时,蒸发率与常规M型阴极相比,分别下降了40.27%和61.45%,与此同时,两种含锶的新型阴极发射电流密度仍能保持较高水平。Sr元素的掺入量对阴极的蒸发性能和发射性能均有明显影响,阴极样品的活性材料蒸发率和脉冲发射电流密度均随Sr含量的升高而降低。     

余核飞行与ΔE—E望远镜双鉴别系统

设计和测试了一套在重离子熔合反应中同时测量蒸发剩余核的质量和电荷的飞行时间谱仪和ΔE-E望远镜双鉴别系统。实验结果表明,该系统对粒子的鉴别能力,Z分辨率好于25,质量分辨可达45。