TD-SCDMA核心网络规划与3GPP TS23．236标准

中国TD-SCDMA一期试商用网基本全部建成,3G时代的步伐日益迫近。研究3G核心网的规划以及如何与2G核心网实现顺利融合、平滑演进的意义重大而任重道远。MSC/SGSNPool技术在3GPP制订的R5版本TS23.236标准中提出后,以其独树一帜的特点引起广泛关注,必将对未来移动通信核心网络发展造成深远的影响。文章深入分析了MSC/SGSNPool技术的特点和实现方式,并研究了TD-SCDMA核心网的规划方法。     

MSC Pool在软交换组网中的应用

本文首先通过对MSC Pool技术原理以及特点优势的介绍,引入Msc Pool在软交换组网中的应用,依次分别阐述了其应用关键点以及发展趋势,从而在兼顾网络资源、注重网络安全的基础上,有效简化网络扩容、合理配置MSC/MSC Server的容量及分担话务.     

二元混合工质HFC23/CFC13池核沸腾传热的实验研究

实验测量了二元混合工质HFC23/CFC13池核沸腾传热特性。加热面为紫铜表面,实验测量的压力范围为0.1~0.55 MPa,热流范围为10 kW/m2~300 kW/m2。实验数据同现有经验关联式的计算结果相比较,发现Fu jita andTsutsu i关联式和Thom e and Shak ir关联式对混合工质HFC23/CFC13的传热系数预测较准确,预测值与实验值之差≤±20%。     

常压下液氮窄缝池沸腾实验研究

采用玻璃钢 (FRP)制成的矩形窄缝 ,对三种不同的间隙尺寸 ,分加热面与水平面呈 0°,4 5°,90°,135°,180°五种角度 ,以液氮为工质进行了 15组池沸腾实验。得出结论 :液氮在窄缝中的沸腾传热有明显的强化换热效果 ;加热面所处角度不同 ,在相同热负荷下壁面过热度亦不同 ,滑移汽泡和微液膜蒸发机理在通道中发挥的作用也相应不同。该研究对于有限空间传热强化的机理和实际应用都有一定的参考价值和指导意义。     

Total Synthesis and Anticancer Activity of (+)‐Hypercalin C and Congeners

The hypercalins are dearomatized acylphloroglucinols with a pendant complex cyclopentane ring that exhibit activity against several cancer cell lines. We report the first total synthesis of (+)‐hypercalin C employing a convergent strategy that enabled the dissection of the essential structural features required for the observed anticancer activity. A strategic disconnection involving an unusual C –C Suzuki–Miyaura coupling with an α‐bromo enolether also revealed an unexpected C?H activation. This strategy targeted designed analogues along the synthetic route to address particular biological questions. These results support the hypothesis that hypercalin C may act as a proton shuttle with the dearomatized acylphloroglucinol moiety being essential for this activity.     

新一代虚拟化客服呼叫中心CTIPool解决方案

本文首先介绍了呼叫中心组网方案的现状,简要说明了现有呼叫中心组网方案中存在的各种问题,并针对这些问题提出了新的CTI Pool解决方案,详细说明了该方案的实现原理、逻辑结构、物理组网和关键部件,并对CTI Pool解决方案的特点做了进一步归纳。     

Influence of surface topography in the boiling mechanisms

The present paper addresses the qualitative and quantitative analysis of the pool boiling heat transfer over micro-structured surfaces. The surfaces are made from silicon chips, in the context of pool boiling heat transfer enhancement of immersion liquid cooling schemes for electronic components. The first part of the analysis deals with the effect of the liquid properties. Then the effect of surface micro-structuring is discussed, covering different configurations, from cavities to pillars being the latter used to infer on the potential profit of a fin-like configuration. The use of rough surfaces to enhance pool boiling mainly stands on the arguments that the surface roughness will increase the liquid–solid contact area, thus enhancing the convection heat transfer coefficient and will promote the generation of nucleation sites. However, one should not disregard bubble dynamics. Indeed, the results show a strong effect of bubble dynamics and particularly of the interaction mechanisms in the overall cooling performance of the pair liquid–surface. The inaccurate control of these mechanisms leads to the formation of large bubbles and strong vertical and horizontal coalescence effects promote the very fast formation of a vapor blanket, which causes a steep decrease of the heat transfer coefficient. This effect can be strong enough to prevail over the benefit of increasing the contact area by roughening the surface. For the micro-patterns used in the present work, the results evidence that one can reasonably determine guiding pattern characteristics to evaluate the intensity of the interaction mechanisms and take out the most of the patterning to enhance pool boiling heat transfer, when using micro-cavities. Instead, it is far more difficult to control the appearance of active nucleation sites and the optimization of the patterns allowing a reasonable control of the interaction mechanisms and in particular of horizontal coalescence, when dealing with the patterns based on micro-pillars. Hence, providing an increase of the liquid contact area by an effective increase of the roughness ratio is not enough to assure a good performance of the micro-structured surface. Despite it was not possible to clearly evidence a pin–fin effect or of an additional cooling effect due to liquid circulation between the pillars, the results show a significant increase of the heat transfer coefficient of about 10 times for water and 8 times for the dielectric fluid, in comparison to the smooth surface, when the micro-patterning based on pillars is used.     

Nucleate pool boiling in microgravity: Recent progress and future prospects

Pool boiling on flat plates in microgravity has been studied for more than 50 years. The results of recent experiments performed in sounding rocket are presented and compared to previous results. At low heat flux, the vertical oscillatory motion of the primary bubble is responsible for the increase in the heat transfer coefficient in microgravity compared to ground experiments. The effect of a non-condensable gas on the stabilisation of the large primary bubble on the heater is pointed out. Experiments on isolated bubbles are also performed on ground and in parabolic flight. The effect of a shear flow on the bubble detachment is highlighted. A force balance model allows determining an expression of the capillary force and of the drag force acting on the bubble.     

Enhancement of the critical heat flux in saturated pool boiling using honeycomb porous media

Enhancement of the critical heat flux in pool boiling by the attachment of a honeycomb-structured porous plate on a heated surface is investigated experimentally using water under saturated boiling conditions. As the height of the honeycomb porous plate on the heated surface decreases, the CHF increases to 2.5 MW/m², which is approximately 2.5 times that of a plain surface (1.0 MW/m²). Automatic liquid supply due to capillary action and reduction of the flow resistance for vapor escape due to the separation of liquid and vapor flow paths by the honeycomb-structure are verified to play an important role in the enhancement of the CHF. A simplified one-dimensional model for the capillary suction limit, in which the pressure drops due to liquid and vapor flow in the honeycomb porous plate balances the capillary force, is applied to predict the CHF. The calculated results are compared with the measured results.     

MSC Pool组网规划研究及问题分析

简要介绍了MSC Pool的技术原理,对目前MSC Pool技术应用存在的问题进行了分析,并针对引入MSC Pool带来的影响进行了探讨,重点讨论了 MSC Pool组网的要点和原则.并给出了MSC Pool组网规划的相关建议.