随机数发生器种子值对岩石试样弹塑性破裂过程的影响研究     

宋力  夏洪春  徐涛 《大连大学学报》2007,28(6):37-42

阐述了岩土类材料的非匀质性特性,以及对岩土类材料弹塑性破裂过程进行数值模拟的分析程序REPFPA,通过8个试样的数值模拟"试验",深入地研究了随机数发生器种子值对岩石试样弹塑性破裂过程的影响.分析结果表明:只要岩石材料力学性质的均质度和其它参数保持不变,随机数发生器种子值对岩石试样弹塑性破裂过程与结果的影响很小.  相似文献   

Cell therapy in congestive heart failure   总被引：5，自引：0，他引：5  

Tao ZW  Li LG 《Journal of Zhejiang University. Science. B》2007,8(9):647-660

Congestive heart failure （CHF） has emerged as a major worldwide epidemic and its main causes seem to be the aging of the population and the survival of patients with post-myocardial infarction. Cardiomyocyte dropout （necrosis and apoptosis） plays a critical role in the progress of CHF; thus treatment of CHF by exogenous cell implantation will be a promising medical approach. In the acute phase of cardiac damage cardiac stem cells （CSCs） within the heart divide symmetrically and/or asymmetrically in response to the change of heart homeostasis, and at the same time homing of bone marrow stem cells （BMCs） to injured area is thought to occur, which not only reconstitutes CSC population to normal levels but also repairs the heart by differentiation into cardiac tissue. So far, basic studies by using potential sources such as BMCs and CSCs to treat animat CHF have shown improved ventricular remodelling and heart function. Recently, however, a few of randomized, double-blind, placebo-controlled clinical trials demonstrated mixed results in heart failure with BMC therapy during acute myocardial infarction.  相似文献   

Stochastic optimal control of first-passage failure for rectangular thin plate vibration model under gaussian white-noise excitations     

葛根  王洪礼 《天津大学学报(英文版)》2011,17(6):431-434

A rectangular thin plate vibration model subjected to inplane stochastic excitation is simplified to a quasinonintegrable Hamiltonian system with two degrees of freedom. Subsequently a one-dimensional Ito? stochastic differential equation for the system is obtained by applying the stochastic averaging method for quasi-nonintegrable Hamiltonian systems. The conditional reliability function and conditional probability density are both gained by solving the backward Kolmogorov equation numerically. Finally, a stochastic optimal control model is proposed and solved. The numerical results show the effectiveness of this method.  相似文献   

触屏式数控机床维修教学设备设计     

李奇亮 《中国现代教育装备》2011,(21):20-22

在数控机床装调与维修实训教学过程中,如何直观高效地进行电气控制线路故障逻辑分析及查找,数控系统参数误设的恢复,故障现象和故障类型的必然性联系判断,采用PMC编程法的机床功能修改以及机电联机调试等实训课题是目前数控设备应用与维护等相关专业学习中普遍存在的难点。针对这些关键问题,基于触摸屏和强抗干扰技术设计出自动设故的数控机床维修教学设备,该设备具有设故高效率、智能化、成本低等特点。该项目的完成为机床装调与维修、电气控制等实训教学创造了有利条件,同时提升了教师的教学水平和学生的综合能力,为进一步扩大校企合作领域奠定坚实基础。  相似文献   

投影机的常见故障及管理维护     

兰淑斌 《中国现代教育装备》2011,(23):29-31

多媒体教学系统所具有的一系列优点和特性,在教育领域尤其是高校得到了广泛应用。从如何保障多媒体教学系统,特别是关键设各投影机在教学环节中能更好地应用出发,结合实际使用情况,以及常见的故障现象和解决措施进行介绍。  相似文献   

从认知关联的角度浅析语用失误     

乔雪宁 《牡丹江教育学院学报》2011,(4):29-30

语言交际以认知为基础,语用失误的原因可以从认知角度进行分析。语用失误与语言使用的认知语境的假设、交际双方之间的明示和推理过程以及理想化认知模式有关。本文从认知语境、明示-推理模式以及理想化认知模式等认知语用学角度,结合关联理论,对语用失误的成因进行探讨。  相似文献   

对董事长的失败惩罚促进了企业创新吗？     

尹希盈 《科研管理》2020,41(4):160-171

本文以2010-2016年中国沪深两市A股上市公司为样本,运用普通最小二乘法和固定效应估计法,探讨全样本和不同技术环境下的企业,失败惩罚和企业创新之间的关系。实证结果表明：对董事长的失败惩罚会提升企业创新的技术水平;失败惩罚和创新绩效之间正相关关系的结论在不同技术环境下具有一般性;进一步比较了失败惩罚与高、低科技企业的交互项系数之后发现,失败惩罚对企业创新的影响在低技术企业样本中显著于高技术企业。  相似文献   

初创企业孵化器运营绩效评价的实证研究 ——创业生态系统视角     

朱思因  杜海东 《科技管理研究》2020,40(7):82-87

从创业生态系统视角,运用数据包络方法,对选取的12家初创企业孵化器运营效率进行评价,发现初创企业孵化器存在生态系统资源互补性差、开放共享性差、服务团队专业能力弱等问题,严重影响其效率的提升。从优化生态系统战略布局、优化生态系统能力结构、打造开放兼容的生态服务系统和建立专业品牌名声等方面提出改进措施。  相似文献   

体育竞赛中的胜败分析   总被引：1，自引：0，他引：1  

郭绍芳 《山西师大体育学院学报》1998,(1)

通过对体育竞赛中胜利和失败这对矛盾的辨证分析,可以帮助运动员正确认识和对待胜利与失败,从而做到失败面前不灰心,胜利面前不骄傲,引导运动员战胜自我,走向成功。  相似文献   

The Subsidized Muse: Government and the Arts in Western Europe and the United States     

Annette Zimmer  Stefan Toepler 《Journal of Cultural Economics》1999,23(1-2):33-49

Using the neo-classical justifications for government support of the arts that Dick Netzer discussed in The Subsidized Muse as a starting point, the article contends that market failure is not an useful concept to understand and explain cultural policies and the degree of government involvement, particularly when viewed from a comparative perspective. The basic fault is that historical- institutional arrangements and the role of non-state actors in the formation of cultural policies are not taken into account. Discussing some aspects of the institutional framework in the development of French, Swedish and U.S. cultural policies, the article concludes with a call for the use of neo-institutionalist perspectives in analyzing government intervention in the arts field.  相似文献