eGiST:一种改进的通用搜索树

新型应用领域的出现,要求数据库系统提供支持数据类型和查询谓词可扩展的索引结构。该文首先介绍了具有这种可扩展性的通用搜索树结构(GiST),分析了GiST在结点溢出处理策略上的不足,并提出了一种改进的通用搜索树结构eGiST,提高了空间利用率和系统效率。     

面向对象技术中标识对象的策略

面向对象（OO）分析模型的核心是对象，如何找出这些对象是OO技术所面临的中心挑战。对标识对象策略的探讨，有助于对OO技术的深入理解和掌握。本文结合需求文档分析工具的对象标识，对相关的问题进行了讨论。     

子系统闭右半平面传输零点对一般二自由度控制系统闭环传递矩阵的限制

对于一般二自由度控制系统，本文讨论了当系统内稳定时，子系统闭右半平面传输零点对系统闭环传递矩阵的限制．这种限制对于闭环传递矩阵满足某些性质时施加了约束．本文的结论扩展了文献［３］的结果．     

在CASE工具中引入XML视图

从数据库设计的角度出发，在CASE(计算机辅助系统工程)工具中添加了创建XML视图的功能，也就是说在使用CASE对实体及其相互联系建模之后，在创建数据库对象的DDL语句的同时自动的创建此数据库的XML视图．具体的方法是将E-R模型转换为DTD来完成了这个数据库的XML视图的创建，一次性的完成了数据库的设计和此数据库的XML视图的创建，从而避免了程序员为了生成视图而对此数据库进行的二次开发，因此提高了工作效率．     

Boiling hysteresis at low temperature on enhanced tubes

The boiling hysteresis phenomenon is studied for a real scale enhanced evaporator tube (2 m long Turbo-B type) with R134a refrigerant used in the flooded evaporator of a centrifugal brine chiller for the ice-making facility. Unlike previous studies of the boiling heat transfer with uniform heat flux and uniform wall temperature, the wall temperature varies along the tube in the present experiment. To see if the similar hysteresis occurs as in the case of uniform wall temperature, a careful control of refrigerant temperature and heat flux is made. We have found hysteresis of the temperature overshoot (TOS) at the onset of nucleate boiling initially at the inlet section of the tube, before it gradually moved downstream section of the tube until the nucleate boiling occupied the whole section of the tube as the inlet temperature increased. The hysteresis became stronger at low refrigerant temperatures. The decreasing trend of heat flux after the contents of the whole tube boiled was different from the increasing trend. This paper provides a guideline how to design the evaporator in order to avoid the abnormal operation of the chillers.     

Reasons for drop in shell-and-tube condenser performance when replacing R22 with zeotropic mixtures. Part 1. Analysis of experimental findings

An experimental and theoretical investigation was made to find out the reasons for the drop in shell-and-tube condenser performance when replacing R22 with a zeotropic mixture R407C. Measurements show that at lower condenser loads the reduction in performance can be as large as 70% compared to the full condenser load. Calculation results are compared with experimental results for two different condensers, one with micro-finned tubes and one with 3-D finned tubes. Calculations show that the degree of mixing of the newly formed condensate on a tube and the drained condensate is a factor influential enough to explain the performance drop. 3-D finned tubes seem to have better mixing in the condensate than integral finned tubes.     

Flash gas bypass for improving the performance of transcritical R744 systems that use microchannel evaporators

The performance of transcritical R744 systems with direct expansion (DX) can be significantly improved by implementing a Flash Gas Bypass (FGB). The idea behind the concept is to bypass refrigerant vapor, created during the isenthalpic expansion process, around the evaporator. By feeding the evaporator with liquid refrigerant, pressure drop is reduced and refrigerant distribution is improved. With R744 as the working fluid, increased refrigerant-side heat transfer coefficients are expected as well. In addition, the FGB concept proves to be beneficial in terms of system design, in particular for combined air-conditioning and heat pumping applications. An experimental comparison to a conventional DX-system reveals that FGB increases the cooling capacity and COP at the same time by up to 9 and 7%, respectively. Even larger improvements are possible in case a variable speed compressor is utilized to match the performance of the conventional DX-system. A simulation model helps to separate the individual improvement mechanisms. It was found that the reduction of refrigerant-side pressure drop is the dominant improvement mechanism of FGB.     

2004 award winners: Distinguished Professional Contributions to Applied Research.

Presents the citations, biographies, and selected papers of the 2004 recipients of the APA Award for Distinguished Professional Contributions to Applied Research (Robert J. Gatchel), the APA Award for Distinguished Professional Contributions to Independent or Institutional Practice in the Private Sector (Miki Paul), the APA Award for Distinguished Professional Contributions to Practice in the Public Sector (Rodney R. Baker), and the APA/APAGS Award for Distinguished Graduate Student in Professional Psychology (Tonia L. Nicholls). The Award for Distinguished Professional Contributions to Applied Research is given to a psychologist whose research has led to important discoveries or developments in the field of applied psychology. The Award for Distinguished Professional Contributions to Independent or Institutional Practice in the Private Sector recognizes outstanding service delivery by a licensed psychologist who is primarily engaged in the practice of psychology in a private sector setting. The Award for Distinguished Professional Contributions to Practice in the Public Sector recognizes outstanding service delivery by a psychologist who is primarily engaged in the practice of psychology in a public sector setting. The APA/APAGS Award for Distinguished Graduate Student in Professional Psychology is awarded on an annual basis by the Board of Professional Affairs (BPA) and the American Psychological Association of Graduate Students (APAGS) to a graduate student who has demonstrated outstanding practice and application of psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of burn-up on the thermal conductivity of uranium dioxide up to 100.000 MWd t

The thermal diffusivity and specific heat of reactor-irradiated UO₂ fuel have been measured. Starting from end-of-life conditions at various burn-ups, measurements under thermal annealing cycles were performed in order to investigate the recovery of the thermal conductivity as a function of temperature. The separate effects of soluble fission products, of fission gas frozen in dynamical solution and of radiation damage were determined. In this context, particular emphasis was given to the behaviour of samples displaying the high burn-up rim structure. Recovery stages could be thoroughly investigated in samples that were irradiated at low burn-ups and/or at high irradiation temperatures. Other samples, in particular those exhibiting the characteristic rim structure, disintegrated at temperatures slightly higher than the irradiation temperature. Finally, from a database of several thousand measurements, an accurate formula for the in-pile thermal conductivity of UO₂ up to 100 GWd t⁻¹ was developed, taking into account all the relevant effects and structural changes induced by reactor burn-up.     

Volume conservation during irradiation growth of Zr-2.5Nb

Dimensional changes are reported in three dimensions for cold-worked Zr-2.5 Nb pressure tube material irradiated to a fast fluence of 174 × 10²⁴ nm⁻², E > 1 MeV at a nominal temperature of 250 °C. The observed dimensional changes in the longitudinal and transverse directions (up to ∼1.2% and ∼−0.5%, respectively) are consistent with earlier data at 280 °C and 310 °C, and the previously reported negative temperature dependence. The observed growth in the radial direction is negative (up to ∼0.7%). Initially, there is a small volume increase (0.05-0.1%) but this gradually decays to < 0.05% and the long term rate of volume change is negligible, within the accuracy of the measurement, demonstrating that the phenomenon observed is, indeed, irradiation growth.