Effects of Large Saddle Panels on the Biomechanics of the Equine Back During Rising Trot: Preliminary Results

The saddle panels, directly in contact with the horse's back, are likely an important element to optimize the fitting of the saddle, the comfort of the horse, and subsequently, the pain management in dorsalgic horses. The aim of this study was to better understand the effect of the saddle panels on the horse's back, by evaluating a prototype saddle (comfort panels: CP) compared to a standard saddle (STD). The horse's back movements were measured using inertial measurement units (IMUs) fixed at the levels of thoracic vertebrae T6, T12, T16 (under the saddle) and lumbar vertebrae L2 and L5. The centers of mass (COMs) of the horse and the rider and limb's protraction-retraction angles, pressure between saddle and horse's back, and force on the stirrups were measured using respectively 2D motion capture, pressure mat and force sensors in the stirrup leather. Three horses were trotted at the rising trot (sitting: left diagonal-rider seated; standing: right diagonal-rider standing) by the same rider. To compare saddles, linear mixed-effects regression models were used. The estimated means (SE) were calculated. During sitting phase, pressure in the cranial and middle areas of the saddle significantly increased for CP compared to STD (+0.9 (0.2) kPa and +1.0 (0.1) kPa, respectively) whereas caudal pressure decreased (−1.8 (0.4) kPa). Concurrently, the range of motion of angles T12-T16 and T16-L2 under the saddle significantly increased (+1.8 (0.2)° and +2.3 (0.3)°, respectively). The results showed that modifications of the panels' shape not only affect the pressure distribution but also the kinematics of the thoracic and lumbar regions of the equine back.     

S195—1型低背压排气消声器的设计研究

本文以内燃机排气噪声必需的消声量频率特性作为设计消声器的依据,论述了扩张室式和穿孔板复合消声器的设计.试验表明,采用这种新型复合消声器后,S195柴油机排气噪声得到了有效控制.     

基于模糊建模的混炼胶粘度测量

提出了一种在线测量混炼胶粘度的新方法．该方法以模糊建模技术为基础，综合考虑混炼过程各因素对胶料粘度的影响，建立起胶料粘度的在线测量模型．在模糊建模中，采用T-S模型描述胶料粘度变化的非线性过程，提出了一种基于相似性判别的模糊聚类算法以自动确定合适的聚类组数目，并用实数编码的遗传算法优化全局参数，从而获得了规则简化的、具有较高精度的模糊模型．根据此方法，设计了测量装置，并进行了现场试验．试验结果表明模糊模型输出与实验室测量值基本一致，平均误差较低且最大误差未超过1门尼．该方法较大地提高了橡胶混炼的生产效率，为粘度最优控制奠定了基础．     

钢筋混凝土结构锈蚀损伤定位

对钢筋混凝土结构锈蚀损伤定位进行了研究,以频率变化平方比作为锈蚀损伤参数,从理论上证明该参数是锈蚀损伤位置的函数。锈蚀钢筋混凝土结构试验结果表明预测的损伤位置和实际的损伤位置较一致,模态参数用于检测混凝土结构构件中的损伤,为大型结构的鉴定和评估提供了新的途径。     

3种农药的微核效应研究

运用蚕豆根尖微核技术研究3种农药(甲胺磷、甲基硫菌灵和盐酸吗啉胍)在不同浓度下的诱变效应。结果表明,3种农药诱发蚕豆根尖细胞微核率与对照组相比均有不同程度的上升(P<0.05或P<0.01),农药浓度与微核率呈剂量-效应关系,盐酸吗啉胍的诱变效应大于其他2种农药。     

负刚度的工作原理及应用初探

This paper deals with the vibration isolation principle of a system with a negative stiffness spring and the energy analysis for this system.As an application of the method, an example of vibration systems with equal frequencies is given. It shows that th     

青藏高原西部狮泉河宽谷区的荒漠化过程

狮泉河宽谷区的荒漠化过程以整个青藏高原的环境演化为背景，受人为的资源利用不合理而强化。今天的宽谷景观一方面隐含了高原宽谷的变化，一方面显示出干旱，退化的主导特征，较之西北干旱区，生态系统更具脆弱性，荒漠化的治理应在发挥区内水资源优质的同时强调生态系统自身的稳定。     

直接利用传递函数对分叉结构进行模态综合

建立了一种直接利用传递函数对分叉结构进行模态综合的方法。传统的方法一般都需要对大矩阵进行求逆运算,而此方法只涉及分叉结构结合部的传递函数矩阵的求逆,因此求逆计算量很小,特别是当直接采用传递函数的测量值进行模态综合时,就更体现出它的优越性。     

步进电机扭矩测量试验台系统的设计

专用电机扭矩测量仪器精度高，但价格昂贵，操作复杂，长时间使用会出现误差。步进电机扭矩测量试验台系统采用单相交流电机作负载，使用标准扭矩仪对该系统进行标定来对待测调速电机进行扭矩测量。为此，介绍了一种电机扭矩测量系统的构成与工作原理。该系统以单片机为核心，组成扭矩测量与显示系统，可以较好地实现电机扭矩在线测量，具有较好的经济效益。     

微波电路电测及其计算方法

从实际工程的角度出发，对电路电测方法进行了论述。在微通信工程中，需要获得障碍物的位置和高度，最合理的天线高度组合和障碍物绕射损耗等参数，为此论述了微波电路电测方法及技术要求。在大庆－秦皇岛输油管道通信工程中采用了Ａ，Ｂ测试法进行测试，得到高度－损耗曲线。这种曲线给出相对自由空间接收电平与收，发天线高度之间的关系。在测试所得的高度－损耗曲线与断面图相结合的基础上，由绕射损耗计算公式推出了几种常见障碍