形意八卦掌的技击特点及对推进中华武术竞技性发展的作用

形意八卦掌是以丰富掌法著称的武术拳种 ,同时它又包含多种腿法 ,其特点为暗、连、诈、准、怪、变等 .本文对形意八卦掌的腿法技击特点及训练法进行研究 ,旨在探讨中华传统武术的技击精华 ,丰富武术散手运动腿法使用 ,重在推进中华武术的竞技性发展 .     

Effect of damping and wave parameters on offshore structure under random excitation

This paper describes the linearized and nonlinear dynamic response of a tension leg platform (TLP) to random waves and current forces. The forcing term of the equation of motion is inherently nonlinear due to the nonlinear drag force. Two analysis procedures are used: nonlinear time domain analysis and linear frequency domain analysis. For the nonlinear analysis, the random wave particle velocities and accelerations are simulated for a given wave spectrum. The nonlinear equation of motion is then integrated directly to obtain the system response statistics. For the linear frequency domain analysis, the nonlinear drag force is linearized through an introduction of linearization coefficients. The main objective of this paper is to investigate the effect of the structural damping and wave parameters on both nonlinear and linear dynamic response of the TLP by parametric studies. The results of stochastic nonlinear and linear dynamic response of the TLP, with and without the presence of current, are presented and compared.     

海洋内孤立波中张力腿平台的水动力特性

基于内孤立波mKdV理论,采用时域有限位移运动方程,结合改进的Morison公式研究了两层流体中内孤立波与张力腿平台(TLP)的相互作用,针对东沙群岛南部海域附近某实测内孤立波特征参数,计算并分析了国际船舶结构力学会议提供的张力腿平台(ISSC-TLP)的内孤立波冲击载荷与运动响应,以及张力腿的张力变化特性.结果表明,内孤立波将对张力腿平台产生突发性的冲击载荷以及大幅度水平漂移运动,并使得张力腿的张力显著增大.     

钢筋混凝土双连梁短肢剪力墙结构试验研究

为了研究混凝土材料随机性对结构反应的影响,进行了4片相同的4层1∶3缩尺模型的双连梁短肢剪力墙结构非线性全过程试验研究.为了使各试件彼此相同,消除其他不确定因素的影响,在结构设计、材料配制、模型施工以及加载制度等方面进行了严格的控制.试验获得了荷载-位移曲线、混凝土和钢筋的应变曲线以及墙体局部相对位移曲线.从水平承载力、侧向刚度、位移延性3个方面对比分析了各片墙体的反应,研究了结构应变、位移的变异性特征,给出了典型横截面受力状态的变化过程,分析了各试件在破坏特征上的差异性.研究结果表明,混凝土随机性与非线性的耦合效应对结构反应所造成的影响不可忽视.     

基于ANSYS的小榄特大桥V型斜腿空间有限元分析

以广州小揽水道特大桥为例,对特大桥V型斜腿部位进行了有限元分析,得到斜腿部位的应力分布情况,以期为类似的结构设计和施工提供理论参考.     

仿猎豹四足机器人结构设计与分析

为满足四足机器人高速奔跑运动性能所要求的脊椎具有柔性和腿结构具有良好的缓冲性能要求,在仿猎豹四足机器人上设计了一种液压驱动的柔性脊椎和腿结构.该脊椎是变截面梁,中间有柔性.该腿结构有髋关节和膝关节,有3个自由度,髋关节有2个主动自由度,即侧摆自由度和俯仰自由度,膝关节具有被动的俯仰自由度.对该脊椎进行了力学分析,对该腿结构进行了刚度特性分析和运动学分析,并对机器人进行了Bound步态仿真.仿真结果表明,这种具有柔性脊椎和非线性刚度变化的腿结构的仿猎豹四足机器人,能够以Bound步态实现较快的稳定奔跑,且足端接触力较小,由此验证了柔性仿猎豹四足机器人脊椎和腿结构的设计是有效的.      

对武术套路运动员腿部力量最佳训练手段的探索

本文试图通过问卷调查,观察和实验,并动用模糊数学理论和模糊相关分析方法,初步探讨武术套路运动员腿部力量最佳训练手段,为腿部力量训练提出理论依据和定量数据．     

基于T-不变量消除的Petri网合法变迁引发序列判定算法

Petri网的合法变迁引发序列问题(LFS)是其可达性问题的子问题.前人在LFS判定时常因判定算法的指数级时空复杂度或算法难以推广至一般Petri网而受限.因此,基于Petri网T-不变量支集变迁与可达图有向环路上标注变迁的对应关系,综合应用线性代数与可达树分析,原LFS判定被缩减为以基础向量为发生数向量的LFSb判定.通过两棵可达树(分别以原网、初始标识;逆网、目的标识为根)层序轮流构造同时比较当前叶节点层中的标识,若算法终止前有相同标识出现,则LFSb(LFS)判定成功;反之,LFS判定失败.分析表明,算法的时间复杂度为多项式级别的,且适用于一般Petri网的LFS判定.     

基于遗传算法的参数在线自调整模糊控制器

提出了一种基于遗传算法优化的自调整模糊控制器的设计方法.该模糊控制器的运行参数自调整公式以系统响应的最大超调量、调整时间及稳态误差为性能指标,利用遗传算法搜索模糊控制器量化因子Ke,Kec及比例因子Ku公式中相应的最优基准值Keo,Keco及Kuo和微调参数K1,K2及K3,设计一个根据系统当前的动态误差e运行参数可在线自调整的模糊控制器,以确保系统的响应具有最优的动态和稳态性能.该控制器已用于控制由作者设计的智能人工腿中的执行电机.计算机仿真结果表明,与运行参数固定的模糊控制器相比,这种自调整模糊控制器具有良好的动态和稳态性能.     

Relationship between Perceived Leg Length Discrepancy at One Month and Preoperative Hip Abductor Muscle Elasticity in Patients after Total Hip Arthroplasty

Objective: Preoperative factors related to perceived leg length discrepancy (PLLD) after total hip arthroplasty (THA) are not well studied. This study aimed to examine the preoperative factors, including hip abductor modulus, related to PLLD one month after THA. Methods: The study included 73 patients diagnosed with osteoarthritis secondary to developmental dysplasia of the hip and a posterior approach to surgery. Multiple logistic regression analysis was performed using the presence or absence of PLLD as the dependent variable and preoperative hip abductor''s modulus of elasticity, pain, hip abduction range of motion, hip abductor muscle strength and pelvic obliquity as the independent variable. Additionally, receiver operating characteristic curves were used for the extracted variables for calculating the cutoffs, sensitivity, specificity and area under the curve (AUC) to determine the presence or absence of PLLD. The significance level was set at p<0.05. Results: The hip abductor modulus (odds ratio=1.13; 95% confidence interval=1.06-1.21; p<0.001) was selected as a preoperative factor. The cutoff value to determine the presence or absence of a PLLD was 16.32 kPa. The sensitivity and specificity were 81.8% and 72.5%, respectively, and the AUC was 0.8137. Conclusion: The hip abductor muscle elastic modulus affected PLLD one month after THA. If the preoperative hip abductor elastic modulus is higher than the cutoff value, it may affect the appearance of PLLD at one month postoperatively.