AHMED experiments on hygroscopic and inert aerosol behaviour in LWR containment conditions: experimental results

Hygroscopic NaOH, CsI, CsOH and inert Ag aerosol behaviour at different temperatures and relative humidities (RH) has been studied in a well instrumented and controlled vessel of 1.81 m³ total free volume. Homogeneous thermal-hydraulic conditions for aerosol measurement in the vessel were achieved. The aerosol number and mass concentration were measured continuously during the experiments using a Condensation Nucleus Counter and a Tapered Element Oscillating Microbalance. The particle size distribution and chemical composition in the test conditions were measured by Berner low pressure impactors. In the case of NaOH the half life of the aerosol mass concentration was more than four times longer at low RH (22%) as compared to high RH (96%). The half lives of the CsOH and CsI aerosols were only twice as long at low RH as compared to high RH. Thus at high RH (96–97%) the half lives of CsOH and CsI were twice as long as the half life for the NaOH aerosol. The faster decay of the NaOH aerosol is due to the smaller density decrease of NaOH during water condensation. CsOH particles grew rapidly to their equilibrium size at all humidities. The measured equilibrium size for CsOH aerosol agree well with the calculated particle size at different RHs. Experimental results were also compared with calculations obtained by severe accident computer codes. These calculated results will be presented in a later paper.     

面向对象的三次参数样条曲线技术

本文利用Ｃ＋＋面向对象的特征，对三次参数样条曲线的定义和生成过程进行封装，从而极大地简化了三次参数样条曲线的定义和绘制过程     

短周期超晶格AlP／GaP能带结构的转变及其带间的光跃迁

介绍了间接跃迁的半导体ＡｌＰ与ＧａＰ形成的超晶格，由于零折叠效应，实现了能带由间接带隙向直接带隙的转变，从而增加了带间的光跃迁几率，并推导了该几率的表达式。     

一种两性离子聚合物的合成性能及应用分析

本文合成了一种两性离子聚合物：丙烯酰胺—二甲基二烯丙基氯化铵—丙烯酸共聚物（ＰＡＤＡ），讨论了三种单体的投料比对产物的组成影响。对它的结构进行了红外表征，就其絮凝、粘土防膨、抗温、抗盐性能进行了研究。结果表明：ＰＡＤＡ具有好的防膨能力和良好的抗温抗盐性能，并有絮凝能力。     

Seeking the truth about ad hoc join costs

In this paper, we re-examine the results of prior work on methods for computing ad hoc joins. We develop a detailed cost model for predicting join algorithm performance, and we use the model to develop cost formulas for the major ad hoc join methods found in the relational database literature. We show that various pieces of “common wisdom” about join algorithm performance fail to hold up when analyzed carefully, and we use our detailed cost model to derive op timal buffer allocation schemes for each of the join methods examined here. We show that optimizing their buffer allocations can lead to large performance improvements, e.g., as much as a 400% improvement in some cases. We also validate our cost model's predictions by measuring an actual implementation of each join algorithm considered. The results of this work should be directly useful to implementors of relational query optimizers and query processing systems. Edited by M. Adiba. Received May 1993 / Accepted April 1996     

磷酸盐玻璃中稀土离子的发光浓度效应研究

磷酸盐玻璃中稀土离子的发光浓度效应研究王民权，马立新，樊先平（浙江大学材料科学与工程系３１００２７）（南京航空航天大学）ＳｔｕｄｙｏｎＣｏｎｃｅｎｔｒａｔｉｏｎＥｆｆｅｃｔｓｏｆＲａｒｅＥａｒｔｈＩｏｎｓｉｎＰｈｏｓｐｈａｔｅＧｌａｓｓｅｓ￥Ｗａｎｇ...     

熔窑玻璃液流数值模拟的新发展

熔窑玻璃液流数值模拟的新发展赵国昌（清华大学核能技术设计研究院，１０００８４）ＮｅｗＤｅｖｅｌｏｐｍｅｎｔｏｆｔｈｅＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｆｏｒＦｌｏｗａｎｄＨｅａｔＴｒａｎｓｆｅｒｏｆＧｌａｓｓＭｅｌｔｉｎＴａｎｋＦｕｒｎａｃｅ￥Ｚ...     

粉末材料中微夹杂缺陷的超声波检验

介绍了用超声波方法检测微夹杂缺陷的一些试验结果，比较了不同频率、不同试验方法检测能力的差异，并通过解剖试验对检出缺陷的性质、尺寸作了比较。     

Mathematical modeling of falling liquid film evaporation process

A mathematical model of evaporation process from a laminar falling liquid film on a vertical plate of constant temperature is presented. The model is developed with and without interfacial shear stress due to the vapor flow at the liquid film surface. The vapor pressure drop, vapor exit velocity and cooling rate are calculated for different liquid mass flow values. It is shown that lower liquid mass flow produces higher cooling rate. The results also show that the interfacial shear stress has a considerable negative effect on the cooling rate. It is proved that there exists an optimum distance between the plates, which gives the maximum volumetric cooling rate.     

Makespan estimation and order acceptance in batch process industries when processing times are uncertain

Batch process industries are characterized by complex precedence relationships between operations, which renders the estimation of an acceptable workload very difficult. A detailed schedule based model can be used for this purpose, but for large problems this may require a prohibitive large amount of computation time. We propose a regression based model to estimate the makespan of a set of jobs. We extend earlier work based on deterministic processing times by considering Erlang-distributed processing times in our model. This regression-based model is used to support customer order acceptance. Three order acceptance policies are compared by means of simulation experiments: a scheduling policy, a workload policy and a regression policy. The results indicate that the performance of the regression policy can compete with the performance of the scheduling policy in situations with high variety in the job mix and high uncertainty in the processing times. Correspondence to: C.V. Ivanescu