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971.
Rafael Cortell 《浙江大学学报(A卷英文版)》2008,9(5):648-653
In this paper a numerical analysis is carried out to obtain the temperature distribution within a single fin. It is assumed that the heat transfer coefficient depends on the temperature. The complete highly non-linear problem is solved numerically and the variations of both, dimensionless surface temperature and dimensionless surface temperature gradient as well as heat transfer characteristics with the governing non-dimensional parameters of the problem are graphed and tabulated. 相似文献
972.
高职院校英语文化环境现状调查及对策分析 总被引:1,自引:0,他引:1
高职院校英语教学和英语学习仍在沿袭以往的传统模式,大部分高职院校教学管理者、英语教师和学生没有"英语文化环境"这一概念,也没有尝试通过优化英语文化环境来提高英语教学质量.文章通过探讨英语文化环境和英语学习的关系,引入多元智能理论即MI理论,探索优化高职院校英语文化环境的各种途径,协助高职学生在均衡发展多元智能同时提高英语实际应用能力. 相似文献
973.
The failure analysis of simply supported, isotropic, square plates is addressed. Attention focuses on minimum failure load amplitudes and failure locations, von Mises' equivalent stress along the plate thickness is also addressed. Several distributed and localized loading conditions are considered. Loads act on the top of the plate. Bi-sinusoidal and uniform loads are taken into account for distributed loadings, while stepwise constant centric and off-centric loadings are addressed in the case of localized loadings. Analysis is performed considering plates whose length-to-thickness ratio a/h can be as high as 100 (thin plates) and as low as 2 (very thick plates). Results are obtained via several 2D plate models. Classical theories (CTs) and higher order models are applied. Those theories are based on polynomial approximation of the displacement field. Among the higher order theories (HOTs) HOTsa models account for the transverse shear deformations, while HOTs models account for both transverse shear and transverse normal deformations. LHOTs represent a local application of the higher order theories. A layerwise approach is thus assumed: by means of mathematical interfaces, the plate is considered to be made of several fictitious layers. The exact 3D solution is presented in order to determine the accuracy of the results obtained via the 2D models. In this way a hierarchy among the 2D theories is established. CTs provide highly accurate results for a/h greater than 10 in the case of distributed loadings and greater than 20 for localized loadings. Results obtained via HOTs are highly accurate in the case of very thick plates for bi-sinusoidal and centric loadings. In the case of uniform and off-centric loadings a high gradient is present in the neighborhood of the plate top. In those cases, LHOTs yield results that match the exact solution. 相似文献
974.
陈青凤 《孝感职业技术学院学报》2021,(1):49-52
“一带一路”倡议的实施要求高职商务英语教学更加突出复合型、应用型人才培养目标,而目前高职英语教学忽视了“一带一路”沿线国家本土化英语表达下的语言障碍,存在课程设置单一、教材内容滞后、师资力量薄弱等问题。为此,必须设置多样化培养课程,采用多元化教学模式与评价方式,推动产教融合,以培养“一带一路”建设所需的优质商务英语人才。 相似文献
975.
A common approach to Lyapunov's stability control is to design a controller such that a Lyapunov function can be derived for the control system to ensure stability. This procedure often leads to a discontinuous controller. When the controller is implemented, the discontinuous terms are replaced with continuous functions to avoid chattering of the control signal. Two associated problems have been overlooked during this procedure. One is that discontinuous control systems are non-smooth, which violates the fundamental assumptions of solution theories and the applicability of Lyapunov's stability theory is questionable. Another problem is that the replacement of discontinuous terms may weaken stability, which can be critical. In this paper, we discuss proper stability analysis of discontinuous control systems using the extended Lyapunov's second method based on Filippov's solution concept for non-smooth systems. We further propose to utilize the concept of Lyapunov exponents to quantitatively analyze the stability of continuous control systems obtained by replacing the discontinuous terms in the discontinuous controllers. An example involving the stabilization of a two-link non-fixed-base robotic manipulator is presented for demonstration. This research fills the gap in designing continuous Lyapunov's stability controllers regarding limited available Lyapunov functions. 相似文献
976.
977.
978.
韩登利 《新乡师范高等专科学校学报》2007,21(2):16-17
结合ODE标准理论和积分方法,通过Lengendre变换,给出了一类拟线性椭圆型偏微分方程整体径向解存在(不存在)的一个充分必要条件。 相似文献
979.
Service failures of turbine blades in many instancescan be attributedto highcyclefatigue caused bylarge reso-nance stress .As dryfrictioninterface may be the most im-portant source of energy dissipation,thefriction damperis atypical devicetoreduce vibrati… 相似文献
980.
略论我国司法解释的问题及对策 总被引:2,自引:0,他引:2
李涛 《云南师范大学学报(哲学社会科学版)》2004,36(1):51-54
司法解释对于弥补法律规范本身存在的缺漏 ,保证法律的正确实施 ,具有重要的作用。目前我国法律实践中的司法解释还存在不少问题 ;对法律的实施产生了消极影响 ,只有采取针对性的措施解决这些问题 ,才能提高司法解释的质量 ,保证法律实施的准确和公正 相似文献