A STUDY ON THE WEIGHT FUNCTION OF THE MOVING LEAST SQUARE APPROXIMATION IN THE LOCAL BOUNDARY INTEGRAL EQUATION METHOD

The meshless method is a new numerical technique presented in recent years .It uses the moving least square (MLS) approximation as a shape function . The smoothness of the MLS approximation is determined by that of the basic function and of the weight function, and is mainly determined by that of the weight function. Therefore, the weight function greatly affects the accuracy of results obtained. Different kinds of weight functions, such as the spline function, the Gauss function and so on, are proposed recently by many researchers. In the present work, the features of various weight functions are illustrated through solving elasto-static problems using the local boundary integral equation method. The effect of various weight functions on the accuracy, convergence and stability of results obtained is also discussed. Examples show that the weight function proposed by Zhou Weiyuan and Gauss and the quartic spline weight function are better than the others if parameters c and a in Gauss and exponential weight functions are in the range of reasonable values, respectively, and the higher the smoothness of the weight function, the better the features of the solutions.     

Liquid Phase Hydration of FCC C4 Mixtures Catalyzed by Zeolite Catalysts

Methyltert butylether (MTBE)asanoctanepromoterinautomobilefuelshasbeenphasedoutinsomecountriesduetoenvironmentalproblems .Thismotivatessubstantialinterestinfindingnewwaysforupgradinggasoline[1,2 ] .TheuseofareplacementforMTBE ,suchasethanol,isafeasiblemethodtoen hancetheoxygenatesandincreasetheoctanenumberofgasoline[3 ] .However ,ethanoldoesnotmixwellwithgasolinebecauseofitstendencytoseparatefromthefuelinthepresenceofwater ,andasolventtoim provethesolubilityofethanolinthefuelmustbeadded .B…     

MODELING TWO-PHASE FLOW IN PULSED FLUIDIZED BED

Mathematical models for pulsed fluidization are systematically discussed. Several undetermined constitutive relationships are included in the General Two-Fluid Model (GTFM), the adjustable parameters of which are always chosen at will to some extent. Although there are no adjustable parameters in the Basic Two-Fluid Model (BTFM), its eigenvalues are complex numbers and it is ill-posed for initial-value problems. The Local Equilibrium Model (LEM), a further simplification of BTFM, is discussed at length. Although the model is very simple, it is highly capable of simulating complex processes in pulsed fluidization over a broad range of operating parameters, and its numerical results well fit experimental results in both the variation of bed height and the distribution of particle concentration as fluidizina velocitv varies.     

宁波北仑山 区种子植物 区系研究

本文通过野外系统调查与标本采集，对宁波北仑山区的种子植物区系组成与性质进行了综合研究.结果表明:本区共有野生种子植物128科、419属,745种。区系组成极为分散，表现为小科、极小科、小属、极小属占有明显的优势，区系的热带—亚热带、温带特征显著，具有亚热带向暖温带过渡区的特性;属的地理成份的分析表明:处于北纬30。线附近的本区域与相近纬度浙江其他山地的植物区系性质相似，并与东部日本植物区系相联系.     

On Bounds for Spectra of Operator Pencils in a Hilbert Space

A class of pencils(operator-valued functions of a complex argument) in a separeble Hilbert space is considered.Bounds for the spectra are derived.Applications to differential operators,integral operators with delay and in finite matrix pencils are discussed.     

Catalytic Dechlorination of Chlorobenzene in Water by Pd／Fe System

Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of the Pd and the total surface area. For conditions with 0.005% Pd/Fe, 45% dechlorination efficiency was achieved within 5 h. The dechlorinated reaction is believed to take place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0043 min^-1.     

天然气管道裂纹稳定扩展问题的分析模型和最小二乘法解答

应用最小二乘法求解了模拟天然气管道裂纹稳定扩展问题的等效染模型，。在Ｗｉｌｌｉａｍｓ等效梁模型的基础上，通过管道裂纹后部截面开裂后变形协调条件。补充了弹性地基对于等效梁的作用，推导出梁的分析模型，并应用最小二乘法求得了裂纹驱动力和位移的解答。其结果与Ｌｅｅｖｅｒｓ所给出的不考虑弹性地基对于梁的作用结果比较，改进了梁模型的计算精度，使裂纹驱动力成为合理的有限值，与已有的试验结果吻合较好。     

转变是北京持续发展的源动力

一个转变 　　主要是被描述为由院所、高校为中心的技术主导型的创新体制向以企业为中心的市场主导型的创新体制的转变. 　　北京是中国的文化和科技中心,北京的高等学府吸引了全国最优秀的人才,同时高校的设施也为开展研究工作提供了支撑. 　　……