排序方式： 共有175条查询结果，搜索用时 15 毫秒
51.
文章从理学教育和工学教育的界定出发,提出我国重点大学本科层面工学教育的目标定位应是培养掌握学科核心知识和基本技能、具备开放性思维和技术创新能力的"未来人才"。结合目前正在实施的"卓越工程师培养计划",分析了工学本科教育的培养策略。认为面向社会发展现状、学生知识结构现状和人才需求现状,综合解决教师和学生面对的"3d"问题,即"应该做""能够做"和"愿意做"的问题,是本科层面工学教育的核心和关键。 相似文献
52.
Incorporating the environmental perturbations and available resources of the public health system, we construct both deterministic and stochastic models of SIRS type. The deterministic model exhibits very rich dynamics, such as Hopf bifurcation and backward bifurcation which leads to the co-existence of the stable disease-free state and a stable endemic equilibrium. For the stochastic model, we show that under mild extra conditions, if the basic reproduction number is less than one, then the disease will be eradicated almost surely, and if the basic reproduction number is greater than one, the stochastic model will admit a unique ergodic stationary distribution, which implies that the disease persists almost surely. Part of our numerical simulations indicate that: (i) The introduction of environmental perturbations may drift the endemic equilibrium to the disease-free equilibrium, or vice versa; (ii) Increasing available resources is necessary in order to mitigate the infections. 相似文献
53.
对于俄罗斯系统使用兴奋剂的行为,国际奥委会执委会以特别决议的方式,授权各国际体育联合会根据自己的规则进行处理。有的联合会,如国际田联,间接通过中止国家协会会籍的方式,也有联合会,如国际举联,直接通过适用决议或自己的规则,使政府责任演变为对比赛权的否定,导致很多俄罗斯运动员无缘于里约奥运会。俄罗斯运动员以违反责任主义原则或者比例原则为由,提起国际仲裁。CAS以这种处理并非是兴奋剂违规处罚,而是其不具备比赛条件,使之避开了法律的限制。当然,《决议》第3条规定除外,因其有悖于"禁止双重危险原则"而被CAS宣布为无效。经过此事件,体育法的一个最大变化是,运动员的比赛权开始与国家协会的管理权解构。 相似文献
54.
对基于智能手机建立大学生个人体育档案系统进行了探索研究,详细论证了以智能手机为终端,为大学生建立基础信息、课堂教学、课外锻炼、综合评价等模块化的个人体育档案,能够为大学生设计差异化的体育学习锻炼方案,在课堂内外跟踪记录大学生锻炼情况并提供健身指导,能够让大学生实时查阅自己的健康信息,积极参与体育锻炼,养成长期自觉坚持锻炼的习惯。 相似文献
55.
简要分析了专业教师兼职班主任的优势,介绍了笔者作为兼职班主任立足专业优势多方面整合校内、校外教学资源开展的“名师名家导学”“多资源助学”“齐抓共管督学”方面的促学实践,并就和谐班级建设的作用,如何处理好与学生、辅导员、校内教师和校外专家的关系总结了心得体会。 相似文献
56.
＂矿物岩石学＂是资源勘查工程专业重要的专业基础课程。根据课程特点,充分利用自然条件,将实验课堂延伸至校园内外石材及野外的多种岩石露头的第二课堂,强化岩矿鉴定技能,构建从传统的实验课堂的验证性学习到实验课堂外的探索性学习的实验课教学新模式。让学生从广阔的大自然中汲取灵感,培养兴趣,激发动力,培养他们的动手能力和创新意识。 相似文献
57.
Two types of passive devices, namely, negative stiffness damper (NSD) and inerter damper (ID), have been receiving growing interest in vibration isolation and suppression, because both can produce negative-slope force-displacement relationships that are similar to those associated with active control forces. Despite such a similarity, these two passive dampers possess obvious differences in their mechanical behaviors. This study aims to illustrate the similarity and difference between these two dampers in vibration isolation applications with respect to the H2 and H∞ performance. The comparative study indicates that both dampers can reduce the H∞ norm effectively; the negative stiffness devices can reduce the H2 norm as well, whereas the H2 norm cannot converge under the influence of inerter. This finding explains why a tuned-inerter damper, i.e., an inerter connected in series with a spring with proper frequency tuning, is more commonly adopted in vibration isolation. The pros and cons of both devices were further discussed. 相似文献
58.
《Journal of The Franklin Institute》2019,356(14):7611-7625
In this paper we investigate an inerter equipped with a prototype continuously variable transmission (CVT) designed for the novel tuned mass damper. Inerter enables stepless changes of inertance via varying transmission ratio of the CVT. The main difference from classical inerter is addition of CVT, hence we present its design and properties in details. Motion of the proposed CVT is oscillatory and we test it for the actual working conditions. We derive the mathematical model of the system that include dissipation via dry friction. We analyse the actual transmission ratio, internal motion resistances and identify the inertia of CVT components using energy conservation method and validate further. Finally, we apply actual working conditions and compare the experimental and numerical exciting torques of the CVT. We obtain good agreement between them, hence the proposed model is robust and gives reliable results. 相似文献
59.
Qun Liu Daqing Jiang Tasawar Hayat Ahmed Alsaedi 《Journal of The Franklin Institute》2019,356(13):7466-7485
In this paper, we investigate the threshold dynamics of a stochastic delayed SIS epidemic model with vaccination and double diseases which make the research more difficult. We establish sufficient conditions for extinction and persistence in the mean of the two diseases. We also obtain the threshold between persistence in the mean and extinction of the stochastic system. It is shown that: (i) time delay and environmental white noise have important effects on the persistence and extinction of the two diseases; (ii) the two diseases can coexist under certain conditions. Finally, some numerical simulations are provided to demonstrate the analytical results. 相似文献
60.
《Journal of The Franklin Institute》2019,356(13):7486-7514
In this paper, a stochastic epidemic model for cholera is proposed and investigated. Firstly, we establish sufficient conditions for extinction of the disease. Then we establish sufficient criteria for the existence of a unique ergodic stationary distribution of the positive solutions to the model by constructing a suitable stochastic Lyapunov function. The existence of an ergodic stationary distribution implies that all the individuals can be coexistent in the long run. Finally, some examples together with numerical simulations are introduced to illustrate our theoretical results. 相似文献