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膝关节不同起始角与结束角运动肌力的生物力学研究 被引量:15
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作者 卢德明 王云德 +2 位作者 方兴 林明芳 麻静媛 《体育科学》 CSSCI 北大核心 1999年第3期84-88,共5页
使用CYBEX—6000型测力系统,对膝关节不同起始角和结束角运动的肌力进行测试,获得了在 60°/s、180°/s和 300°/s 3种速度下,9种不同起始膝角、结束膝角、运动幅度中,屈伸膝肌群的峰力矩、总功、平均功率等参数,并进行了... 使用CYBEX—6000型测力系统,对膝关节不同起始角和结束角运动的肌力进行测试,获得了在 60°/s、180°/s和 300°/s 3种速度下,9种不同起始膝角、结束膝角、运动幅度中,屈伸膝肌群的峰力矩、总功、平均功率等参数,并进行了分析研究。发现屈伸膝肌群的峰力矩、总功和平均功率均随着运动幅度的增大而增大。 展开更多
关键词 膝关节 肌力 等动向心 起始 结束角 运动幅度
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倾斜圆盘勺式精密排种器清种过程分析与试验 被引量:27
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作者 李成华 夏建满 何波 《农业机械学报》 EI CAS CSCD 北大核心 2004年第3期68-71,共4页
以排种器工作过程中种子的受力分析为基础 ,建立了排种器清种起始角和清种结束角的理论计算公式 ,分析了倾斜圆盘勺式精密排种器结构参数和工作参数对充种和清种性能的影响。通过试验确定了排种器对 3种不同玉米种子的充种和清种极限速度。
关键词 倾斜圆盘勺式精密排种器 清种过程 清种起始 清种结束角 结构参数 工作参数
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Formation Mechanism and Binding Energy for Equilateral Triangle Structure of He3^+ Cluster 被引量:6
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作者 GOU Qing-Quan ZHANG Jian-Ping LI Ping 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第5期597-600,共4页
The formation mechanism for the equilateral triangle structure of the He-3(+) cluster is proposed. The curve of the total energy versus the internuclear distance R for this structure has been calculated by the method ... The formation mechanism for the equilateral triangle structure of the He-3(+) cluster is proposed. The curve of the total energy versus the internuclear distance R for this structure has been calculated by the method of a modified arrangement channel quantum mechanics. The result shows that the curve has a minimal -7.81373 a. u at R = 1.55 a(0). The binding energy of He-3(+) with respect to He+He++He was calculated to be 0.1064 a.u. (about 2.89 eV). This means that the He-3(+) cluster may be formed in the equilateral triangle structure stably by the interaction of He+ with two helium atoms. 展开更多
关键词 He-3(+) cluster binding energy equilateral triangle structure
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INDEX OF DIRECTION CHANGE OF ZONALLY AVERAGED WIND AND CHANGE OF SEASON
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作者 朱敏 徐建霞 张铭 《Journal of Tropical Meteorology》 SCIE 2011年第2期128-135,共8页
In this paper, a Wind Direction Change Index (WI), which can describe four-dimensional spatiotemporal changes of the atmospheric circulation objectively and quantitatively, is defined to study its evolution and season... In this paper, a Wind Direction Change Index (WI), which can describe four-dimensional spatiotemporal changes of the atmospheric circulation objectively and quantitatively, is defined to study its evolution and seasonal variation. The first four modes can be obtained by EOF expansion of the zonally averaged WI. The first mode reveals the basic spatial distribution of the annually averaged WI. The second mode reflects the quasi-harmonic parts of the WI deviations. Tropical, subtropical and extratropical monsoon areas can be clearly reflected by this mode. The third mode reflects the non-harmonic parts of the WI deviations. It shows the so-called February reverse in stratospheric atmosphere as well as the asymmetric seasonal changes from spring to fall and from fall to spring due to both the land-sea distribution contrast between the Northern and Southern Hemispheres and the nonlinear effect of atmospheric and ocean fluids. The fourth mode reveals the northward advancing of the global reversed wind fields from spring to summer and their southward withdrawal from summer to autumn. 展开更多
关键词 Wind Direction Change Index (WI) Empirical Orthogonal Function (EOF) four-dimensional space-time changes February stratospheric reverse
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