通识课程内容的探讨——以知识分类理论为依据     

陈小红  马乐诚 《复旦教育论坛》2008,6(3):23-27

本文试图以泰克西纳的知识领域划分对哈佛大学、芝加哥大学、香港中文大学、北京大学的通识课程进行考察。研究发现,中外大学的通识课程基本上覆盖所有的知识领域;中外大学均有数量比较多的文学、音乐和艺术评论及历史课程;不同的大学在通识课程开设中各有传统和偏重。  相似文献   

Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system   总被引：2，自引：0，他引：2  

高红  傅新  杨华勇  Tsukiji Tetsuhiro 《浙江大学学报(A卷英文版)》2002,3(4):395-400

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)  相似文献   

高速铁路超大断面隧道施工方法数值模拟研究     

苏江 《襄樊学院学报》2011,32(5):42-47

针对高速铁路软弱、浅埋超大断面隧道,采用双侧壁导坑法、三台阶七步法两种施工方法分别进行三维数值模拟和开挖方法的科学性进行对比分析,结果表明:在施作大管棚超前支护的前提下,三台阶七步法比较合理.研究结论为同类工程的设计和施工提供理论参考.  相似文献   

Inter-Parietal White Matter Development Predicts Numerical Performance in Young Children     

Cantlon JF  Davis SW  Libertus ME  Kahane J  Brannon EM  Pelphrey KA 《Learning and individual differences》2011,21(6):672-680

In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children's developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to test the link between the development of the corpus callosum and performance on symbolic and non-symbolic numerical judgment tasks. We were especially interested in the interhemispheric connections of parietal cortex in 6-year-old children, because regions of parietal cortex have been implicated in the development of numerical skills by several prior studies. Our results revealed significant structural differences between children and adults in the fibers of the corpus callosum connecting the left and right parietal lobes. Importantly, these structural differences were predictive of individual differences among children in performance on numerical judgment tasks: children with poor numerical performance relative to their peers exhibited reduced white matter coherence in the fibers passing through the isthmus of the corpus callosum, which connects the parietal hemispheres.  相似文献   

怎样求函数EXP~((q))的可接受有理逼近   总被引：2，自引：0，他引：2  

杨逢建 《湘潭师范学院学报(社会科学版)》1990,(3)

本文首先得到了函数R_(?)~s(q)是函数exp(q)的各类可接受有理逼近的必要条件,其次证明了exp(q)的含有s+t-p~*个自由参数的不低于p~*阶的有理逼近存在,且对于参数的每一组给定值,逼近式唯一.接着就逼近阶P≧2s-2,s≧2情形给出了exp(q)的双参数有理逼近R_s~s(q_ib_(s-1),b_s)和三参数有理逼近R_(s+1)~s(q_ib_(s-1),b_s,b_(s+1))的系数计算公式,并由此得到了求exp的含有多个自由参数的有理逼近的一般方法.  相似文献   

微通道内单相水流动与换热的特性研究     

胡月莲 《温州职业技术学院学报》2006,6(4):36-38

微通道传热技术是近几年发展起来的一门新兴的传热技术,具有传热效率高、结构紧凑等优点,是当前流动与传热研究的重要课题。运用计算流体力学程序(CFX)对环形微通道内单相水的流动与换热进行数值模拟,可以形象地描述出管内的流场和温度场,从中分析各种因素对流动与换热所产生的影响。  相似文献   

数控车撞刀问题的分析与解决     

丘志敏 《洛阳工业高等专科学校学报》2004,14(2):17-18,48

撞刀是数控车培训过程中易出现的问题之一。为了更进一步减少撞刀问题的发生和提高学生的数控综合素质．通过对撞刀事故发生的原因进行分析与总结，提出了一些防止发生撞刀事故的方法与措施，这对数控车技能人才的培养有着非常鲜明的指导意义。  相似文献   

教师培训学习结果的多维度解析   总被引：1，自引：0，他引：1  

陈霞 《教育科学》2011,27(4)

从教育目标分类学的视角对教师培训学习结果构成所做的元分析为教师培训目标与结果的表述提供了有价值的参照;从教师素质构成分析的视角对教师培训学习结果所做的元分析为理解教师培训活动的实际结果提供了可资借鉴的参考;从培训评估的视角对教师培训学习结果所做的元分析为理解教师培训结果的不同层次提供了一定的借鉴。  相似文献   

沿空留巷巷旁充填墙体合理尺寸优化研究     

贾建功  侯昌盛  刘辉  孟翠翠 《毕节学院学报》2011,29(4):124-128

沿空留巷实现了无煤柱开采,是煤矿生产中的重大技术改革。整体浇注巷旁充填技术是我国近年来研究和应用的先进巷旁支护技术。为了保持正常生产,就必须保证巷旁充填墙体稳定性。应用现场观测法,根据沿空留巷围岩应力随工作面推进的变化规律,研究了下区段煤体应力变化规律以及充填墙体稳定性。运用FLAC-3D数值模拟软件,模拟了4种不同宽度时的充填墙体稳定性,研究表明,墙体宽度大于或等于2m时,巷道围岩塑性区范围明显减小,支护效果较好。  相似文献   

淡水真菌多样性及研究进展概述     

刘晓英  陶星辰  罗宗龙  苏鸿雁 《楚雄师范学院学报》2015,(3):48-53

本文旨在介绍淡水真菌,简要地讨论了淡水真菌的研究历史、作用、形态、分类以及中国的研究现状。淡水真菌是潜在的物质分解者和化学生产者,我们希望广大读者能对淡水真菌学领域产生浓厚的兴趣。  相似文献