第18届篮球世界杯16强球队的攻防实力评价

目的了解当今世界篮坛的竞争格局及各队的整体实力,为我国竞技篮球发展提供参考。方法运用文献资料法、录像观察法、TOPSIS法、RSR法等对第18届篮球世界杯16强球队的攻防技战术指标进行分析。结果与结论1)在进攻方面,塞尔维亚、美国2队的进攻进攻能力较强(>0.67);在防守方面,澳大利亚、阿根廷、美国、西班牙4队的防守能力较强(>0.719)。2)在攻防综合能力方面,根据RSR值的大小可以将16支球队划分为5档。3)在进攻指标上,得分、助攻、投篮命中率、三分命中数、被侵犯5项指标在不同档次球队间存在极显著性差异(p<0.01),进攻篮板、投篮命中数、三分命中率3项指标在不同档次球队间存在显著性差异(p<0.05)。4)在防守指标上,防守篮板、个人犯规、防守犯规3项指标在不同档次球队间存在显著性差异(p<0.05)。     

校园足球联赛品牌的构建

长期以来,校园足球联赛品牌形象的打造上始终难有起色,本文通过文献资料法和访谈法对校园足球联赛品牌的构建进行理论研究,为校园足球联赛品牌建设提供理论依据和参考模型,最终得出结论:校园足球联赛品牌构建的核心是联赛品牌文化、联赛品牌标识和优质联赛产品。校园足球联赛品牌构建离不开电视媒体、平面媒体、网络媒体、移动数字媒体、明星营销等媒体的公关与宣传以及对校园足球联赛品牌的保障。建议:各级政府应大力推进普及校园足球,解决家长和校长动力机制,改善足球教学训练环境,让更多的学校参与校园足球联赛是打造校园足球联赛组织者的当务之急;打造有效的联赛组织体系对联赛品牌进行运作和管理,形成系统的长期性的联赛体制。     

基于LabVIEW的信号处理技术应用演示及实验系统设计

介绍了信号处理技术应用演示和实验系统的设计思想,给出了系统的总体设计方案及部分设计案例.利用LabVIEW的图形化可视化编程优势,通过虚拟仪器来实现信号处理理论在实际中的典型应用(如:信号产生器、数字音响效果处理、声音信号的去噪、双音多频数字电话按键信号的产生与检测等).该系统一方面可辅助课堂教学,另一方面可作为虚拟实验平台供学生课后实验练习,使学生加深对信号处理理论的理解,激发学生的学习兴趣和创新意识,提高教学效果.     

巧用配积法推广一类初中数学竞赛题

1问题原解 题1已知实数a、b≠0,令 x=a/｜a｜＋b/｜b｜＋ab/｜ab｜. 则x的最大值与最小值的和是___．     

从信息技术文化的诠释推进课程改革

从信息的传播、人类信息技术的发展和信息技术的社会影响等方面诠释信息技术文化.从诠释中启示课程在内容呈现方式、实施的组织形式、学生学习行为和接受信息的途径、课程教学理念等上发生变革.     

校外教育与学校教育资源共享与互补机制研究——来自北京、昆明与满洲里三城市的深度访谈报告

加强校外教育机构与中小学校的合作,促进校内外教育资源的共享与互补.形成强有力的教育合力,是未成年人健康发展的需要.深度访谈表明,我国校外教育机构与中小学校的合作取得了初步成效,但还存在不少问题.文章在分析了影响校外教育与学校教育资源共享与互补的主要因素的基础上,提出了问题解决的对策与建议.     

Performance of a single-stage Linde-Hampson refrigerator operating with binary refrigerants at the temperature level of-60 ℃＊

The optimization of the performance of a single-stage Linde-Hampson refrigerator （LHR） operating with six different binary refrigerants （R23/R134a, R23/R227ea, R23/R236ea, R170/R290, R170/R600a and R170/R600） with ozone depletion potentials （ODPs） of zero was conducted using a new approach at the temperature level of-60℃. Among these binary refrig- erants, the 0.55 and the 0.6 mole fractions of R23 for R23/R236ea are the most prospective nonflammable ones for the medium and low suction pressure compressors, respectively. For these two kinds of compressors, the 0.6 and the 0.65 mole fractions of R170 for R 170/R600, respectively, are the most prospective binary refrigerants with low global warming potentials （GWPs）. The results of optimization of pressure levels indicate that the optimum low pressure value for coefficients of performance （COP） is achieved when the minimum temperature differences occur at both the hot and the cold ends of the recuperator at a specified composition and pressure ratio. Two useful new parameters, the entropy production per unit heat recuperated and the ratio of heat recuperating capacity to the power consumption of the compression, were introduced to analyze the exergy loss ratio in the recuperator. The new approach employed in this paper also suggests a promising application even to the optimization of the performance with multi-component refrigerants.     

Influence of baffle position on liquid sloshing during braking and turning of a tank truck

The influence of baffle position on liquid sloshing during the braking and turning of a tank truck was studied using a volume of fluid (VOF) model. The forces,their positions and weight distribution during braking and the forces and rolling moment during turning were calculated. The reliability of the calculation method was validated by comparisons with experimental results. The results showed that during braking,liquid splashes in the tank and the maximum forces and G (the ratio of weight acting on the front axle to the rear axle) are large when A (the ratio of the arch area above the baffle to the area of cross section)≤0.1. When A≥0.2,as the position of the baffle is lowered,the maximum of Fx (the force in direction x) first decreases then increases,and the maximum of Fy (the force in direction y) and G increase. During turning,liquid splashes in the tank and the maximum forces and M (the rolling moment) are large when D (the ratio of the arch area above the baffle to the area of cross section)≤0.2. When D≥0.3,as the position of the baffle is lowered,the maximums of Fy,Fz (the force in direction z) and M increase.     

A long-term in situ calibration system for chemistry analysis of seawater

An in situ calibration system is a versatile exploration instrument for electrochemical sensors investigating the biochemical properties of the marine environment. The purpose of this paper is to describe the design of an auto-calibrating system for electrochemical （pH） sensors, which permits two-point in situ calibration, suitable for long-term measurement in deep sea aqueous environments. Holding multiple sensors, the instrument is designed to perform long-term measurements and in situ calibrations at abyssal depth （up to 4000 m）. The instrument is composed of a compact fluid control system which is pressure-equilibrated and designed for deep-sea operation. In situ calibration capability plays a key role in the quality and reproducibility of the data. This paper focuses on methods for extending the lifetime of the instrument, considering the fluidics design, mechanical design, and low-power consumption of the electronics controller. The instrument can last 46 d under normal operating conditions, fulfilling the need for long-term operation. Data concerning pH measured during the KNOX18RR cruise （Mid-Atlantic Ridge, July-August, 2008） illustrate the desirable properties of the instrument. Combined with different electrodes （pH, H2, H2S, etc.）, it should be of great utility for the study of deep ocean environments, including water column and diffuse-flow hydrothermal fluids.     

利用网络进行协作学习的研究

建构主义理论强调以学习者为中心,学生是学习过程的主体,是知识意义的主动建构者。网络环境下的协作学习恰好体现了建构主义理论的观点。利用网络进行学习,满足了广大学习者的要求,促进了教学,但也给教师和学习者提出更高的要求。