Determination to Weighting Coefficient of Combination Forecast Based on Rough Set Theory

The problem of determination to weighting coefficient is a key and difficulty for combination forecast. A method of determining weighting coefficient based on rough set theory is showed in this paper. Determining weighting coefficient is translated into estimating significance of attributes among rough set. A relation data model about combination forecast is established. Knowledge systems are built through making attribute value into eigenvalue. Under data moving, the weighting coefficients of a combination forecast model are computed by analyzing the dependence and significance of forecasting method for the predicted object. The proposed approach overcomes the subjectivity of traditional determination to weighting coefficient, avoids computing linear or nonlinear extremum problem and makes combination forecast more objective. The validity of the proposed approach is verified with a case.     

Deformation of deep foundation pits due to excavation and dewatering considering the change of void ratio and permeability coefficient with current stress of soil

基于修正剑桥模型理论,推导了孔隙比e随土体当前应力变化的方程,同时比选了4组经典的描述渗透系数k随孔隙比变化的方程,选择了其中一组最佳的估算公式,编写ABAQUS用户子程序VOIDRI和USDFLD,以实现孔隙比和渗透系数随土体当前应力的变化。在此基础上,研究深基坑降水开挖所致的坑内外土体的变形、围护结构的变形及弯矩,得到以下结论：当考虑孔隙比随土体当前应力变化时,坑外地表沉降量、墙体的水平位移、地下连续墙的弯矩、坑底隆起量均大于孔隙比为定值时的情况;当考虑渗透系数随土体当前应力变化时,坑外地表沉降量、墙体的水平位移、地下连续墙的弯矩均小于渗透系数为定值时的情况,但同时考虑渗透系数和孔隙比变化情况时,其对坑底的隆起量的影响可以忽略不计。     

Application of Multivariate Statistics in Early-warning of Corporation Financial Crisis

This paper is focused on early warning of corporation financial crisis for the China's household electric appliance manufacturers in stock market. Firstly, using company's open-disclosed annual statements as data resource, the financial indexes system is constructed. Secondary, adopting the multivariable statistical analysis method, such as cluster, discriminate and principle component analysis, the multivariate models for the empirical study on early warning of financial crisis by making use of SPSS statistical software are set up. The corporation might discover the financial affairs crisis that shall probably arise beforehand by using the financial affairs crisis early warning system. This study and analysis may serve as reference for domestic industries and enterprises.     

60Co-γ射线辐射对香福禄考发芽率及幼苗长势的影响

用60Co-γ射线辐射香福禄考种子,观察其发芽率和幼苗生长情况。结果表明:30、60 Gy辐射对发芽率有促进作用,60、70 Gy辐射则对幼苗生长有很好的促进作用。     

低能离子注入后小麦苗期损伤效应研究

以鉴54、豫农118及豫麦18号为材料,研究了不同剂量率、剂量离子注入对小麦幼苗生长的影响。结果表明,随着剂量率和剂量的增加小麦幼苗损伤程度逐渐加剧,具体表现在苗高降低、第一叶长变短。剂量率间差异显著,品种间有辐射敏感性差异。另外苗期还发现了一些变异,主要表现为主叶脉失绿和形态畸形。离子束诱变的合适剂量在6×1017ions/cm2以上。     

水稻与高梁属间远缘杂交花粉管行为观察

水稻和高粱是禾本科的两个异属作物,因其遗传距离较远,杂交表现不亲和,结实率极低,难以获得种子.为初步了解水稻与高粱属间远缘杂交花粉管行为,探索该远缘杂交的发生过程,本实验以籼稻珍汕97A×珍汕97B和Ⅱ-32A×Ⅱ-32B两个组合为对照,对珍汕97A×晋江多枝高粱和Ⅱ-32A×晋江多枝高粱两个属间远缘杂交组合的花粉管行为作初步的观察与研究,结果表明晋江多枝高粱花粉粒能象水稻花粉粒一样在水稻柱头上正常萌发,花粉管在花柱及子房中生长与伸长,有些能最终到达子房的基部;同时高梁花粉管生长也出现诸如不能进入花柱、胼胝质不规则堆积、花粉管末端钝化等一系列的异常表现,致使不少花粉管停滞生长.     

屏蔽泵抗汽蚀性能的试验

介绍了低汽蚀屏蔽泵的结构和工作原理，分析了该种泵的性能特点以及汽蚀产生的原因等，提出了提高抗汽蚀性能所采取的措施。从改善叶轮进口几何形状的设计方法方面来降低泵的汽蚀余量，例如叶轮进口直径Dj，叶片进口安放角β1，叶片进口边的形状，叶片数，叶轮进口流道形状等。对两台屏蔽泵进行了性能试验：通过能量性能试验确定出扬程H、输入电机功率N、机组效率ηgr与流量Q之间的关系，通过汽蚀性能试验确定临界汽蚀余量△hc与流量Q之间的关系。结果表明，两种规格屏蔽泵的性能均达到了设计的要求。     

摆动式花生收获机整体载荷的试验与分析

从理论上建立了摆动式花生收获机的空间力系模型.在此基础上,围绕摆动式花生收获机的主要试验参数-传动速比、偏心距、栅条长度与前进速度的改变进行了摆动式花生收获机整体载荷的试验.试验证明:花生收获机在工作时所受载荷平衡,通过二次回归旋转组合试验测定整体载荷随4因素的变化规律是显著的,结合花生收获机的实际工作条件分析了回归方程的适用范围.本试验为摆动式花生收获机在功率消耗、力的平衡等方面的进一步改进提供了依据.     

车用493型柴油机冷却问题初探——机体冷却水流动CFD模拟

车用493型柴油机在我国主要是轻卡的配套动力,量大面广。为了在提高升功率的同时满足国家排放要求,很多研究工作主要着重于强化结构件、改进气道及工作过程、提高供给系统的喷油压力等,在冷却方面着力不够。实际上冷却不均衡,热应力集中同样会造成机体变形,导致颗粒物排放上升。冷却效果的好坏又在很大程度上取决于冷却水套内冷却介质流动以及分布的情况。本文从冷却分析入手,利用CFD商用流体软件STAR-CD对车用493型柴油机的冷却系统中的机体内冷却水的流动进行了三维数值模拟,给出冷却水套内冷却介质的流动场,分析它对换热的影响。