NONPROPORTIONAL CYCLIC PLASTICITY FOR METALLIC MATERIALS     

Peng Xianghe Fan Jinghong Ma Mingtu 《保鲜与加工》1992,(3):73-79

In order to describe nonproportional cyclic plasticity of polycrystalline metallic materials, the hardening function is separated into three factors, in which,f1 is related to the hardening parameter determined by plastic strain range, and f2 and f3 are related to the change of plastic deformation path characterized by a measure of nonproportionality. The main features of this work are: (a)cyclic hardening is described by f1, and additional hardening is separated into instantaneous and hereditary one which is described by f2 and f3 respectively; (b)a general form of the evolution of f1(i= 1,2, 3) is proposed; (c)parameters a1 and a3 are introduced to keep the memory to the largest cyclic hardening and additional hardening respectively; (d)various hardening mechanisms are embedded into a thermomechanically consistent constitutive equation. The capability of the developed model is verified with the analysis of biaxially nonproportional experiments by Benallal et al, Tanaka et al and Ohashi et al.  相似文献   

A NUMERICAL STUDY ON NATURAL CONVECTION IN A CLOSED CAVITY PARTIALLY FILLED WITH POROUS MEDIUM     

Cao Jiming Xia Jiliang Xin Mingdao 《保鲜与加工》1992,(6):85-91

The present paper decribes numerical analytical results of natural convection in a closed cavity partially filled with porous medium by means of Forchheimer-Brinkman model. The effects of heated rate,permeability,height of porous region,heat conduction coefficients and aspect ratio on flow and heat transfar in the cavity are systematically investigated. Velocity and temperature fields in the cavity are given and dependence of average Nu on time is obtained.  相似文献   

Empirical Study of the Support System of New Venture Creation     

CAO Yang  REN Yu-long 《保鲜与加工》2006,(9):156-161

The Support System of New Venture Creation is the main parts of national and regional innovation system. At presently ,many study on the Support System are from angle of view of the macro or government ,little study from the New Venture. University Science Park in China have enough New Venture which can be the representation of New Venture Creation. The authors study the former theory ,use the method of Empirical Study, Based on the questionnaire investigation of Chongqing University Science Park, analyze different requirements of the enterprises in different sizes and different stages, and bring forward some advises.  相似文献   

Empirical Study on the Sustainable Growth of the Public Companies in China     

LIU Bin  HUANG Yong hong  LIU Xing 《保鲜与加工》2002,(9):150-154

The sustainable growth is the corporation's final object to the maximum of the stock-holder's wealth. To validate the development of the Chinese public companies after Dengxiaoping's Nanxun speech ,this paper tests the sustainable growth status of the Chinese public companies during the period from 1993 to 2000 by using mathematical statistics method and sustainable growth model brought forward by Robert Higgins and James Van Herne. These companies are classified by trade. The test results show that no trade realized sustainable growth except electronic and electric trade. Results also indicate that public companies in light industry and agricultural sectors have a trend of under-investment while those in other sectors have a trend of over investment.  相似文献   

基于层次分析法的江西省可持续食物安全评价   总被引：1，自引：0，他引：1  

吕爱清  卞新民 《土壤》2007,39(5):819-823

选取化肥用量等23个指标,采用层次分析法测算江西省可持续食物安全度.结果表明,1978-2003年江西省可持续食物安全度逐步提高,目前食物处于安全水平.江西省食物生产因子、资源禀赋因子和气候因子安全水平较高,对食物安全较有保障;食物保障因子和社会经济因子安全水平偏低,是可持续食物安全的薄弱环节;可持续环境因子的安全水平正逐步加强,有利于提高可持续食物安全度.  相似文献   

提高烟草抗旱能力的研究进展   总被引：1，自引：0，他引：1  

何礼军  周冀衡  杨虹琦 《安徽农业科学》2006,34(2):261-262

从生理学角度已研究出一些提高烟草植株抗旱能力的技术措施,如营养物质诱导、变温变光刺激、生长调节剂处理,同时也从生物化学与分子生物学的角度,通过诱变或转入与抗旱性有关的重要基因研究出了一些烟草抗旱品种。  相似文献   

科学实验中动物致死方式的选择   总被引：1，自引：0，他引：1  

苏敬水  刘炳琪 《畜牧兽医杂志》2012,31(2):51-53,56

在动物科学、动物医学或人类医学科研工作中,常常见到在实验过程或实验结束后,为节约成本等需要,会将实验动物致死,抱着对生命的敬畏,对动物选择适当的致死方式,使动物痛苦降低到最低程度,将成为每个科研人员必修的一课,这不但有利于科研结果得出正确的结论,也完全符合动物福利原则。  相似文献   

基于产业链发展的职业院校食品加工类专业群构建研究——以河南省为例     

孙向阳  侯丽芬  隋继学 《农产品加工．学刊》2012,(10):166-168

论述了河南省高职院校食品加工类专业群建设与食品产业链发展现状及存在的问题,提出了基于产业链发展的高职院校食品加工类专业群构建原则。  相似文献   

石化企业循环经济发展综合评价及实证研究     

杨晓龙  王华 《东北林业大学学报》2012,40(6):149-152

依据循环经济的相关理论,构建了涵盖减量化、再利用、无害化3个子系统的石化企业循环经济发展水平综合评价体系。运用层次分析法确定各指标权重系数,采取模糊综合评价法对石化企业循环经济发展水平进行综合评价,在此基础上对某石化企业进行了实证研究。  相似文献   

开发区域的累积环境影响及实例分析   总被引：1，自引：0，他引：1  

林扬碧  钟同畅 《安徽农业科学》2012,40(34):16741-16744

在探讨开发区域的累积效应行为与类别的前提下,深入分析区域活动累积环境影响的响应方式,建立相对应的4种累积环境影响的理论计算模型。最后,以海南省某一开发区作为实例,运用全幕景分析方法,结合区域景观结构分析、海域水动力模型等背景技术,在累积环境影响识别的基础上,通过开发区域的土地利用变异、全幕景变化,对开发区域的陆生生态、近岸海域生态进行累积环境影响分析。  相似文献