从磁浮列车的噪声谱变化中观察多普勒效应

通过对磁浮列车行驶时产生的噪声进行现场测试及分析,比较了列车靠近和离开时的噪声功率谱,观察并定量计算了其谱线频率的变化,从而为声波的多普勒效应提供了有效的教学及实验方法,也可为磁浮列车或其他高速列车行驶噪声的进一步研究提供有效的测量分析方法。     

高校自然地理教学的核心任务——现代地理学科能力的培养

结合多年教学实践,提出自然地理教学,不仅应当传授最基本的理论与专业知识,而且更重要的是要教给学生如何利用所学的知识和特有的地理思维方法去分析问题、发现问题与解决问题。并且探讨了在自然地理教学中培养现代地理学科能力的途径。     

财务管理课程实验体系建设

高校财务管理课程是一门应用性很强的课程,有必要修改现有教学大纲,建立财务管理课程实验体系。这个体系由课程认知环节的实验、课程中的实验和期末综合设计实验3个环节构成,在目前国内财务管理课程建设中并不多见。     

机械加工实践教学要以培养能力为主线

实训教师是实践教学的组织者和实施者,要有很高的道德水准和娴熟的技术能力。在课题选择上要紧紧把握住从书本知识转化为实践技能这一环节。让学生在实践中进一步加深对理论的理解,培养学生成为有能力的高级技术人才。     

Study on hydrodynamic vibration in fluidic flowmeter

The characteristics of the fluidic flowmeter,which is a combination of impinged concave wall and bistable fluid amplifier,is investigated by experimental studies and numerical simulations. The numerical approaches are utilized to examine the time dependent flow field and pressure field inside the proposed flowmeter. The effect of varying structural parameters on flow characteristics of the proposed fluidic flowmeter is investigated by computational simulations for the optimization. Both the simulation and experimental results disclose that the hydrodynamic vibration,with the same intensity,frequency and 180° phase shift,occurs at axisymmetric points in the feedback channel of the fluidic flowmeter. Using the structural combination of impinged concave wall and bistable fluid amplifier and differential signal processing technique,a novel fluidic flowmeter with excellent immunity and improved sensibility is developed.     

Effects of slag fineness on durability of mortars

In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS) replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects, exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Conse- quently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.     

Research on the operating characteristics of parallel 4-DOF electric platform with 4TPS-PS structure

The 4TPS-PS parallel platform designed for a stabilization and automatic tracking system is a novel lower-mobility parallel mechanism. In the first part of this paper, the structure of the platform is described and the kinematics model is built. The workspace of the platform is defined as the full reachable rotation workspace when the Z coordinate dimension of the upper plate varies continuously. A fast searching method of the full reachable workspace is presented, after which the inverse kinematics of the platform is deduced. The forward and inverse solutions of the speed and force of the platform are deduced. According to the characteristic of the 4TPS-PS platform’s structure, a fast searching algorithm of the maximum generalized speed and maximum generalized force output by the upper plate is put forward based on the forward and inverse solutions of the platform’s speed and force. The 4TPS-PS platform prototype built by the State Key Laboratory of Fluid Power Transmission and Control of China is taken as the research subject. The full reachable rotation workspace of the prototype is computed out and analyzed. The curves of maximum generalized speed and maximum generalized force of the prototype are computed out and plotted. Finally, the com- puting and analyzing results of the operating characteristics are confirmed through the experiment.     

英语教学中思维能力的培养模式及其对教师的要求

英语思维在英语学习中占有重要地位,英语教学中的三种不同思维能力培养模式即自发思维能力培养模式、启发思维能力培养模式、合作思维能力培养模式,相互促进,相互联系。从不同思维能力培养的角度,对知识的传授者——教师也提出了不同的要求。     

义务教育均衡发展机制的欠缺与完善 ——以广州地区为例

目前，相关法律政策的落实以及配套机制的欠缺，制约和影响了义务教育均衡发展。本文以广州地区在推进义务教育均衡发展过程中存在的困扰为例，在对当前义务教育实施过程中存在的制度落实和机制欠缺问题分析的基础上，提出了完善义务教育均衡发展机制的建议。     

试论设立公务员“终身成就奖”

公务员"终身成就奖"是有关国家机关根据公务员管理法规的相关规定,对长期在工作中勤政廉政,忠于职守、表现突出、有显著成绩和贡献的公务员给予精神的和物质的奖励。当前设立公务员终生成就奖是必要的,但需要对奖励的原则、条件、种类、程序、权限等内容进行规定。公务员终身成就奖的设立有利于公务员勤政廉政的长效激励机制的建立,也是对公务员奖励制度的完善。