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71.
致泻大肠埃希氏菌O157:H7(STEC O157:H7)是大肠埃希氏菌中致病性最严重的一种食源性致病菌,主要存在于牛肉、牛奶、水果及其制品中,对身体健康造成很大危害,甚至引发死亡。食品中STEC O157:H7检测尤为重要。本文对国内外STEC O157:H7的检测标准进行比较,提出我国标准在样品前处理、快速筛选方法的应用等方面需要加强,以便为该菌快速准确检测提供帮助,实现与国际标准化体系建设接轨,满足实验室检测需要。  相似文献   
72.
73.
Earning report is a main accounting report that transmits earning information to users. It is the core of financial reports system. Earning information is significant to users' decision making. This paper studies the respond of stock trading volume to earning report and draws the curve of trading volume before and after earning report. This paper further does a regression analysis of accidental earning and abnormal return rate, and draws the relation curve of them on the earning report date to prove stock trading volume does have remarkable respond to earning report. This research is significant to either lessen small investors blindness investment and help them make reasonable forecast to markets and regulate the disclosure of listed companies.  相似文献   
74.
Employing the standpoint of irrational investors in the behavior finance, the authors study the relation on the irrational behavior of medium and small Investors and underpricing of IPO in our country. The paper premises that a revenue-maximizing issuer will be regarded as the target function, and the rational institutional investors can be delegated the task of holding the stocks in the after-market for resale to the irrational medium and small investors--thereby extracting surplus from them, finally the issuer can maximize their expected revenue. We model the process mentioned above and find that the high underpricing of IPO in our country has the direct relation with numerous the irrational medium and small investors existing in our country who cause the underpricing.  相似文献   
75.
Many factors affect the propagation of ultra high frequency(UHF) signals caused by partial discharge(PD) on the waveforms and energy of signals in transformer.To investigate the relationshi Pof factors and UHF signals,simulation model of transformer for PD study are established.UHF signals in simulation model of transformer caused by PD are calculated using finite difference time domain method.By means of amplitude and cumulative energy plot of simulation signals,and combing the measured result,the following factors:distance between PD source and detection position,different metallic conductor position around detection position and iron core and winding are researched,which contribute to comprehend the propagation characteristic of UHF signals and detect UHF signals accurately.  相似文献   
76.
Based on experience in customer service evaluation,through the analysis of many factors affecting customer satisfaction calculation estimate, customer service evaluation rules as well as customer-oriented and supply chain partner-oriented methods are developed and discussed from the view of supply chain, besides, we construct two sets of customer satisfaction evaluation systems, in which we perform non-dimensional analysis on evaluation system to form single factor evaluation matrix after using improved AHP to determine each factor item's weighting ,utilizing fuzzy decision theory to construct evaluation model for integrated estimate. This evaluation method is scientific, round and objective with more stability and convienience in practical use.  相似文献   
77.
For the inequality constrained nonlinear programming problem, the antnors propose a new lower order penalty function, which combines the classical l1 penalty function and the lower order exact penalty function introduced in thoy some papers, and then illustrate that it has the merits of the two penalty functions. In additional, we propose a solution method for solving the inequality constrained nonlinear programming problem and prove its global convergence.  相似文献   
78.
区域物流规模发展预测方法研究   总被引:1,自引:0,他引:1  
区域物流是全国乃至国际物流系统的重要组成部分,对区域经济的发展具有服务引导作用。本文对我国物流发展进行了分析,对灰色预测模型GM(1,1)的建模过程进行了研究,用已预测值和GM(1,1)原始序列一起做精度检验,根据未来数据的变化,设计了改进型的灰色预测模型,并结合实例进行了应用研究,得出了更接近实际的预测结果。通过误差检验,改进模型具有较高的预测精度,是一种非常实用的预测方法。  相似文献   
79.
热泵式节能烘干机的设计   总被引:2,自引:0,他引:2  
热泵是一种使热量从低温介质流向高温介质,以对高温物体进行供热的装置.为此,利用热泵原理研究设计了一种小型高效节能烘干机,并介绍了该机的主要特点、总体结构等,尤其对热泵、烘干床进行了详细介绍.该机具有结构简单新颖、造价低廉、使用寿命长、高效节能等优点,不仅可以烘干多种农产品,还可以烘干茶叶、蘑菇等多种农副产品.  相似文献   
80.
通过对辽宁东港灌区稻田排水沟距的综合对比试验分析,探讨了该地区稻田不同排水沟距对控制地下水位、渗漏量、土壤Eh值及水稻产量的影响,初步提出该地区稻田适宜的排水沟距。为今后该地区及类似地区排水沟道的规划设计提供了借鉴和参考,对水田的增产增收具有重要意义。  相似文献   
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