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101.
Satoru Hashizume Hiroaki Hobara Yoshiyuki Kobayashi 《European Journal of Sport Science》2019,19(6):757-764
Negative work, which is mainly generated by eccentric muscle contraction, has an important influence on the associated muscle damage. Generally, mechanical parameters are determined for one side of a lower extremity on the assumption of negligible between-limb differences. However, between-limb differences in the negative work of lower extremity joints during running remain unclear. This study examines between-limb differences in negative work and associated mechanical parameters during the contact phase of running. Twenty-five young adult males voluntarily participated in this study. Each participant was asked to run on a straight runway at a speed of 3.0?m?s?1. Negative work, amplitude, duration of negative power, moment, and angular velocity were computed for both sides of the lower extremities. Significant differences were found in negative work between limbs for the hip (18.9?±?11.7%), knee (13.6?±?10.4%), and ankle (11.8?±?8.5%) joints. For the hip joint, asymmetric negative work was attributable to the between-limb difference in the amplitude of negative power owing to a corresponding difference in the moment. The between-limb differences concerning the duration and amplitude of negative power could explain the asymmetric negative work in the knee joint. The asymmetric negative work of the ankle joint was attributable to the between-limb difference in the amplitude and duration of the negative power and the moment. These results indicate that asymmetric negative work was generated in each lower extremity joint; however, the major mechanical parameters corresponding to the negative work are not the same across the joints. 相似文献
102.
在重轨干涉实际测量中,两次飞行航迹难以保持高度重合,飞行高度和姿态不稳定,干涉图像对存在明显不规则的相对形变,难以进行三维定位。通过分析重轨机载InSAR图像对的几何形变和形成原因,提出一种从精准的InSAR成像几何关系出发,通过修正成像参数,实现机载重轨InSAR高精度三维定位的方法。该方法通过引入地面控制点,实现干涉图像对精准的相对定位,生成高精度DEM;并利用高精度DEM,实现机载重轨InSAR高精度三维定位。对比检查点实测结果和定位结果,表明该方法可有效地解决机载重轨InSAR的三维定位困难的问题。 相似文献
103.
Rony Ibrahim Gert S. Faber Jaap H. van Dieën 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):45-57
Attaining high speed of the stick head and consequently of the ball is essential for successful performance of the drag flick in field hockey, but the coordination pattern used to maximise stick head speed is unknown. The kinematics of the drag flick was studied in ten elite hockey players who performed twenty shots each towards a target located 1.5 m high. A 150 Hz active marker motion analysis system was used, alongside two force plates to detect foot touchdown. Angular velocity and contribution to stick endpoint speed of upper body joints were analysed. Repeated measures ANOVA was used to compare timing of onset and peak angular velocities between joints. Participants used a kinematic pattern that was close to a proximal-to-distal sequence. Trunk axial rotation and lateral rotation towards the target, right wrist flexion and left wrist extension were the main contributors to stick endpoint speed. Coaches should emphasise trunk rotations and wrist flexion and extension movements for maximising stick head speed. Given the high level of the participants in this study, the coordination of joints motions, as reported here, can serve as a guideline for drag flick training. 相似文献
104.
Alexis Herbaut Emilie Simoneau-Buessinger Franck Barbier Christophe Gillet Maxime Roux Nils Guéguen 《European Journal of Sport Science》2017,17(10):1261-1269
Compared to traditional tennis shoes, using 0-drop shoes was shown to induce an immediate switch from rear- to forefoot strike pattern to perform an open stance tennis forehand for 30% of children tennis players. The purpose of the study was to examine the long-term effects of a gradual reduction in the shoe drop on the biomechanics of children tennis players performing open stance forehands. Thirty children tennis players participated in 2 laboratory biomechanical test sessions (intermediate: +4 months and final: +8 months) after an inclusion visit where they were randomly assigned to control (CON) or experimental (EXP) group. CON received 12-mm-drop shoes twice, whereas EXP received 8?mm then 4-mm-drop shoes. Strike index indicated that all CON were rearfoot strikers in intermediate and final test sessions. All EXP were rearfoot strikers in intermediate test session, but half the group switched towards a forefoot strike pattern in final test session. This switch resulted in a decreased loading rate of the ground reaction force (?73%, p?=?.005) but increased peak ankle plantarflexors moment (+47%, p?=?.050) and peak ankle power absorption (+107%, p?=?.005) for these participants compared with CON. Biomechanical changes associated with the long-term use of partial minimalist shoes suggest a reduction in heel compressive forces but an increase in Achilles tendon tensile forces. 相似文献
105.
Pradeep Jeganathan 《Inter-Asia Cultural Studies》2013,14(3):446-451
Abstract How is the content of a literary canon, or tradition to be configured? What counts as a literary archive? More than 25 years after Edward Said’s Orientalism (1978), it seems reasonable to assume, that central to such traditions, would be the work of those who live and work in the society that gives rise to it. In this review, such a location of Michele de Kretser’s new novel, The Hamilton Case, is offered, as a caution to metropolitan literary critics who continue to approach Sri Lankan writing in English, as Christopher Columbus approached ‘America’. It is argued that the novel owes much to, and can be read as echoing and elaborating the detective fiction of S.W.R.D. Bandaranaike, who was, also, the fourth Prime Minister of Ceylon (Sri Lanka), 1956–59. 相似文献
106.
陈亚梅 《荆门职业技术学院学报》2007,22(12):42-45
基于TI公司的DSP芯片TMS320F2812,对其外围电路进行设计,实现一个数字控制的硬件系统,并在此基础上进行相应的软件设计,最终实现一个相对完整的数字控制系统。 相似文献
107.
全固态电视发射机具有智能化管理、平均故障率低、保护功能可靠完善等优点。其功放单元和供电单元采用积木化、冗余化设计,有完善的保护、指示功能,以及热插拔和激励器主备自动切换,这就决定了电视发射机维护观念和维护模式发生改变,使发射机功率放大器模块成为发射机主要的维护对象。本文以泰克诺公司生产的BT03-103S型全固态电视发射机为例,介绍全固态电视发射机功率放大模块AU152及其故障与维护。 相似文献
108.
基于虚拟现实技术的救助船对外消防培训仿真系统 总被引:1,自引:0,他引:1
针对救助船消防训练中存在的海况复杂,对外消防炮射流受风影响大,往往无法准确控制其射向目标区域的问题,在理想状态下射流理论的基础上探究风对射流轨迹的影响,建立自然风条件下射流轨迹的数学模型,模拟对外消防炮射流的运动情况。应用3ds Max构建船舶模型,用Unity3D构建救助船在面临大风浪、遇险船着火等状况时对外消防系统的工作场景,提出一种精确构建粒子系统轨迹的方法,使射流模型能精确体现在场景中。通过虚拟现实设备能实现救助船对外消防培训仿真系统的立体显示和人机交互,起到更好的虚拟仿真和培训效果。 相似文献
109.
三维形态在平面设计中的应用分析 总被引:1,自引:0,他引:1
孙晓洁 《佳木斯教育学院学报》2013,(11)
随着当今社会中经济和科技文化的快速发展,人们生活的各个领域都得到了相应的拓展,而人们物质与精神文化需求的提高,也使得单纯的二维形态对事物的表现形式已经远不能满足人们的生活。在三维空间中,事物的表现形式也逐渐发展起来,本文便是通过对三维形态的概念介绍及特征分析讲述了其在平面设计中的应用。 相似文献
110.
本文基于VB开发的用于高校的邮件群发系统,对邮件发送过程的技术实现做了说明,针对群发登陆的安全加密算法做了深入的探讨,应用本系统进行高校学生管理和服务相关的邮件发送,为提供高校的工作效率,增强对学生的服务效果起到了积极的促进作用。 相似文献