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浅析110米栏现代技术直线性特征 被引量:1
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作者 郭言斌 《松辽学刊(自然科学版)》 2001年第3期95-96,共2页
本文通过对 1 1 0米栏的全程跑和各技术动作的分析 ,论证出直线性是现代 1 1
关键词 110米栏 直线性特征 速度 跨栏跑 身体重心轨迹 摆动腿技术 起跨腿技术
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Analysis of nonlinearities and effects in direct drive electro-hydraulic position servo system 被引量:2
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作者 王洪杰 季天晶 +1 位作者 毛新涛 刘全忠 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第1期6-10,共5页
The direct drive electro-hydraulic servo system is a new approach hydraulic system. It is much smaller and easier controlled than traditional systems and is a perfect energy saver. This paper will briefly introduce th... The direct drive electro-hydraulic servo system is a new approach hydraulic system. It is much smaller and easier controlled than traditional systems and is a perfect energy saver. This paper will briefly introduce the popular nonlinearities in the electro-hydraulic system and analyse the effect of nonlinearities in direct drive electro-hydraulic position servo system by means of simulation research. Some valuable conclusions are given. 展开更多
关键词 direct drive electro-hydraulic system NONLINEARITIES EFFECT
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Straight line feature based image distortion correction 被引量:1
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作者 Zhang Haofeng Zhao Chunxia Lu Jianfeng Tang Zhenmin Yang Jingyu 《Engineering Sciences》 EI 2008年第2期83-86,96,共5页
An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion ... An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion parameters by nonlinear least square. The thought of step by step was added when the optimization method working. 3D world coordination is not need to know, and the method is easy to implement. The experiment result shows its high accuracy. 展开更多
关键词 distortion correction straight line feature nonlinear least square multi-step optimization
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Characteristics of nonlinear evolution of wavepackets in boundary layers 被引量:1
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作者 YU Min LUO JiSheng LI Jia 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第2期250-256,共7页
The nonlinear evolution of a finite-amplitude disturbance in a 3-D supersonic boundary layer over a cone was investigated recently by Liu et al. using direct numerical simulation (DNS). It was found that certain sma... The nonlinear evolution of a finite-amplitude disturbance in a 3-D supersonic boundary layer over a cone was investigated recently by Liu et al. using direct numerical simulation (DNS). It was found that certain small-scale 3-D disturbances amplified rapidly. These disturbances exhibit the characteristics of second modes, and the most amplified components have a well- defined spanwise wavelength, indicating a clear selectivity of the amplification. In the case of a cone, the three-dimensionality of the base flow and the disturbances themselves may be responsible for the rapid amplification. In order to ascertain which of these two effects are essential, in this study we carried out DNS of the nonlinear evolution of a spanwise localized disturbance (wavepacket) in a flat-plate boundary layer. A similar amplification of small-scale disturbances was observed, suggesting that the direct reason for the rapid amplification is the three-dimensionality of the disturbances rather than the three-dimensional nature of the base flow, even though the latter does alter the spanwise distribution of the disturbance. The rapid growth of 3-D waves may be attributed to the secondary instability mechanism. Further simulations were performed for a wavepacket of first modes in a supersonic boundary layer and of Tollmien-Schlichting (T-S) waves in an incompressible boundary layer. The re- suits show that the amplifying components are in the band centered at zero spanwise wavenumber rather than at a finite spanwise wavenumber. It is therefore concluded that the rapid growth of 3-D disturbances in a band centered at a preferred large spanwise wavenumber is the main characteristic of nonlinear evolution of second mode disturbances in supersonic boundary layers. 展开更多
关键词 boundary layer WAVEPACKET nonlinear evolution second mode spanwise small-scale disturbance
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