Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump

The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here.     

埋地换热器放热工况的现场运行实验研究

结合一地源热泵示范工程，建立了垂直竖井与地基桩单U型管埋地换热器联合使用的地源热泵系统的综合性能实验装置。通过对一个夏季长期间歇运行测试数据的分析，发现地下各个测点的温度上升幅度各不相同；桩埋管的热作用半径至少为2．5m，井埋管的热作用半径至少为2m；在相同的工况条件下，桩埋管的放热率大于井埋管。     

Optimal performance characteristics of a solar-driven heat pump at maximum COP

The effect of the irreversibility of finite-rate heat transfer on the performance of a solar-driven heat pump is investigated by using the theory of finite time thermodynamics. Maximizing the COP of the system leads to some novel rules for the optimum choices of primary performance parameters, such as the operating temperatures of the solar collector and the working fluid in the heat exchangers and the heat transfer areas of the heat exchangers. These rules can guide the evaluation of existing real solar-driven heat pumps or influence the design of future solar-driven heat pumps.     

室温下的主动锁模Ho:YAG激光器

为了获得在2m波段的百皮秒激光器,采用主动锁模的方法,使用Tm∶YLF作为抽运源,得到了可在室温下工作的输出连续锁模脉冲的主动锁模Ho∶YAG激光器。研究了该主动锁模激光器的输出特性,并进行了实验验证,取得了脉冲重复频率为82.75MHz、输出最大平均功率为1W、激光中心波长为2097.25nm、斜率效率为13.3%、锁模脉冲宽度约为86.6ps的实验数据。结果表明,采用主动锁模的方式能获得输出脉宽百皮秒量级的锁模钬激光器。     

采用有限状态机控制的升降压双通路高效率电荷泵

针对诸如系统芯片中模拟和数字模块需工作在不同电源电压下的要求,提出一种可同时提供双路输出且具有多种增益模式的电荷泵,它仅利用一组开关电容阵列,根据输入电压与负载电流的变化自动为双通路选择合适的增益对,从而在提供稳定的输出电压同时使电荷泵具有较高的转换效率。专门引入增益跳变技术,改善了增益过渡的平滑性,进一步提高了转换效率。整个调制过程采用数字状态机控制,电路结构简单,响应速度快。芯片采用TSMC 0.35μm混合信号CMOS工艺设计并制造,仿真与测试结果显示设计目标均已实现,能够同时提供稳定的1.8 V和5.0 V的双路输出,动态响应迅速,转换效率比传统多增益模式电荷泵提高了10%以上。     

LD连续和脉冲抽运的Nd：YAG腔内倍频蓝光激光器

在激光二极管连续抽运的Nd：YAG激光器中,分别采用BIBO和LBO晶体对946nm激光进行腔内倍频,获得473 nm蓝光输出。抽运功率9.5 W时,BIBO晶体倍频输出功率为508mW,转换效率5.35%：LBO晶体倍频输出功率为441 mW,转换效率4.64%。LBO倍频的转换效率小于BIBO,但输出蓝光的光束空间质量较好。在LD脉冲抽运和LBO晶体腔内倍频的Nd：YAG激光器中,研究了抽运脉冲的调制频率和占空比与蓝光输出功率的关系。当抽运功率9W,脉冲调制频率100Hz、占空比60%时,得到最大的蓝光输出功率465mW,比相同功率连续抽运提高87mW。结果表明,LD脉冲抽运能有效降低Nd：YAG晶体的热效应影响,提高激光器输出功率。     

PT泵的微机测试系统的设计

为实现PT泵的自动化测量,以单片机为核心设计一种多功能PT泵检测系统。该系统具有燃油流量检测、油泵压力检测、油温检测、转速检测等功能,可实现PT泵各种参数的数字化测量,并且具有功能齐全、结构简单等特点．适用于多种PT泵的性能检测。     

化学机械抛光浆料研究进展

化学机械抛光(CMP)作为目前唯一可以实现全面平坦化的工艺技术,已被越来越广泛地应用到集成电路芯片、计算机硬磁盘和光学玻璃等表面的超精密抛光.介绍了CMP技术的发展背景,以及目前国内外抛光浆料的研究现状,并根据CMP浆料磨料的性质,将其分为单磨料、混合磨料和复合磨料浆料,对每一种浆料做了总体描述.详细介绍了近年来发展的复合磨料制备技术及其在CMP中的应用,并展望了CMP技术的发展前景以及新型抛光浆料的开发方向.     

不同压力下螯合剂浓度在碱性Cu CMP中的影响

We propose the action mechanism of Cu chemical mechanical planarization(CMP) in an alkaline solution.Meanwhile,the effect of abrasive mass fraction on the copper removal rate and within wafer non-uniformity(WIWNU) have been researched.In addition,we have also investigated the synergistic effect between the applied pressure and the FA/O chelating agent on the copper removal rate and WIWNU in the CMP process.Based on the experimental results,we chose several concentrations of the FA/O chelating agent,which added in the slurry can obtain a relatively high removal rate and a low WIWNU after polishing,to investigate the planarization performance of the copper slurry under different applied pressure conditions.The results demonstrate that the copper removal rate can reach 6125 °/min when the abrasive concentration is 3 wt.%.From the planarization experimental results,we can see that the residual step height is 562 ° after excessive copper of the wafer surface is eliminated.It denotes that a good polishing result is acquired when the FA/O chelating agent concentration and applied pressure are fixed at 3 vol% and 1 psi,respectively.All the results set forth here are very valuable for the research and development of alkaline slurry.     

高压变频器在华电贵州大方电厂300MW火电机组凝结水泵上的应用

随着高压变频装置应用领域不断扩大,300MW机组凝结水泵上也开始应用。300MW机组配套的凝结水泵采用变频装置后,流量的调节不再依靠传统的阀门或回流方式。本文结合华电贵州大方电厂的变频改造项目,介绍了凝泵变频系统的特点,使用变频调速装置不仅可以达到明显的节能目的,更主要是调节性能好,同时也改善了水泵和电动机起动问题,延长了设备的使用寿命,降低了现场设备的维护量。