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.     

水力喷砂割缝增产增注技术的作用原理及展望

本文对从俄罗斯引进的水力喷砂割缝技术的发展过程、工作原理及该技术在大庆油田的试验情况做了详细的阐述。并对它的改进及其将来的推广与发展前景做了展望。     

二滩拱坝混凝土设计及试验研究

二滩水电站混凝土双曲拱坝，坝高２４０ｍ，是我国已建和在建的第一高坝。根据拱坝应力状况，仿真试验试件尺寸，二向、三向轴受力状况混凝土的力学变形特性，建立了相应的方程式。二滩拱坝混凝土强度设计龄期为１８０ｄ，抗渗标号不小于Ｓ１２，抗冻标号选用Ｄ２００，胶材用量不超过２００ｋｇ／ｍ３，也不少于１７０ｋｇ／ｍ３，粉煤灰掺量控制在３０％以内，Ａ、Ｂ、Ｃ三区混凝土强度分别采用３５、３０、２５ＭＰａ。经试验和复核，大坝混凝土强度的安全系数是完全足够的。     

80m高钢筋砼烟囱的爆破拆除

论述了控制爆破拆除钢筋砼烟囱的方案设计与力学计算、爆破参数确定、施工方法、安全防护措施、震动监测和爆破效果.     

6m焦炉移动设备故障分析及处理

对6m焦炉移动设备运行特点及损坏原因进行了分析，并对6m焦炉移动设备PLC系统，液压系统的故障及其处理方法进行了探讨。     

A damage identification technique for CF/EP composite laminates using distributed piezoelectric transducers

In this study, a damage identification approach was developed for carbon fibre/epoxy composite laminates with localized internal delamination. Propagation of the Lamb wave in laminates and its interaction with the delamination were examined. The fundamental symmetric Lamb wave mode, S₀, and the lowest order shear wave mode, S₀^′, were chosen to predict damage location. A real-time active diagnosis system was therefore established. This technique uses distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. The two-way switches were employed to minimize the number of transducers. A signal-processing scheme based on the time–frequency spectrographic analysis was utilised to extract useful diagnostic information. Also, an optimal identification method was applied on damage searching procedure to reduce errors and obtain the diagnostic results promptly. Experiments were conducted on [0/−45/45/90]_s CF/EP laminates to verify this diagnosis system. The results obtained show that satisfactory detection accuracy could be achieved.     

Mesh data structure selection for mesh generation and FEA applications

The data structure representing a mesh and the operators to create and query such a database play a crucial role in the performance of mesh generation and FE analysis applications. The design of such a database must balance the conflicting requirements of compactness and computational efficiency. In this article, 10 different mesh representations are reviewed for linear tetrahedral and hexahedral meshes. A methodology for calculating the storage and computational costs of mesh representations is presented and the 10 data structures are analysed. Also, a system for ranking different data structures based on their computational and storage costs is devised and the various mesh representations are ranked according to this measure. Copyright © 2002 John Wiley & Sons, Ltd.     

液压转向助力系统能耗特性的分析和比较

 为了提高汽车转向系统的工作效率，利用在典型路面条件下获得的实验统计数据，分析了中位开式和中位闭式两种液压转向助力系统的能量消耗． 经过对4种不同工作原理的转向系统的经济性和环境适应性的评价，指出电动中位闭式系统在节能方面具有明显的优势，但在工程应用中仍有不少技术问题需要进一步解决．     

压电类智能层合结构的力学和计算模型综述

综述了压电类智能层合结构的力学和计算模型。基于大量国内外有关压电类智能层合结构的文献 ,根据各自采用的运动学假设、场变量的近似、压电层的表达法以及曲率和温度的影响 ,对压电层合结构的力学和计算模型进行了分类 ,阐述了各种理论的特点及一般形式。     

Optimal Solutions for the Temporal Precedence Problem

Abstract. In this paper we refer to the Temporal Precedence Problem on Pure Pointer Machines . This problem asks for the design of a data structure, maintaining a set of stored elements and supporting the following two operations: insert and precedes . The operation insert (a) introduces a new element a in the structure, while the operation precedes (a,b) returns true iff element a was inserted before element b temporally. In [11] a solution was provided to the problem with worst-case time complexity O (log log n ) per operation and O(n log log n) space, where n is the number of elements inserted. It was also demonstrated that the precedes operation has a lower bound of Ω (log log n ) for the Pure Pointer Machine model of computation. In this paper we present two simple solutions with linear space and worst-case constant insertion time. In addition, we describe two algorithms that can handle the precedes (a,b) operation in O (log log d ) time, where d is the temporal distance between the elements a and b .