两轴稳定平台大俯仰角状态控制技术研究

在对两轴稳定平台一般构型分析的基础上,指出了其在俯仰方向大角度时稳定控制存在的不足,提出了采用三正交陀螺稳定控制方式解决大俯仰角控制问题的方法,最后利用MATLAB进行了数学仿真,结果表明该方法有效提高了系统的稳定精度。     

提高涤／氨纶弹力深色织物色牢度工艺探讨

对涤/氨弹力深色织物染色工艺进行了实验分析。实验结果表明,选择汽巴WW分散染料,设计合理的还原清洗条件,可提高涤/氨弹力织物耐洗色牢度,能够克服涤/氨弹力布深色色牢度差和成衣拼白效果不良的缺点。     

A Method of Determining the Axes of a Three-Component Magnetometer Sensor with Respect to the Axes of the Navigation System of a Ferromagnetic Mobile Object

A method of determining the orientation of the axes of a three-component magnetometer sensor with respect to the axes of the navigation system of a ferromagnetic mobile object is considered, which eliminates the effect of the magnetization of the object on the determination of the angular position of the axes of the sensor with respect to the axes of the navigation system.     

Complex chain of momentum transfer of body segments in the baseball pitching motion

Abstract

Baseball pitching requires contributions from and interaction among all limb segments. Most previous investigators have concentrated on the throwing arm itself, but the center of mass (COM) and contribution of all segments in the pitching motion have not been studied. The purpose of this study was to investigate the momentum transfer of all body segments in the pitching motion. The kinematics pitching motion data were captured from three experienced pitchers (one is professional, two are amateurs). A ten‐segment body system was modeled in this study. The results showed that the lowest position of the COM during the pitching cycle occurred around the ball release time and the fastest velocity (2.81±0.18 m/sec) of the COM was in the late cocking phase. The trunk and thigh on the throwing side showed the largest linear momentum among all segments in the late cocking phase. The upper throwing arm and forearm had peak linear momentum in the acceleration phase. The trunk also had the largest angular momentum during the pitching cycle and reached the maximum rotational momentum (4.17±1.22 Kg‐m²/sec) in the late cocking phase and medial bending momentum (9.03±5.78 Kg‐m²/sec) at the end of the late cocking phase. From the time sequence of linear momentum changes, especially in the leading direction, the force transfer from the foot to the trunk then through the upper extremity during the pitching motion was identified. The largest change rate of angular momentum found in the trunk meant that the trunk contributed the largest torque in the pitching motion. Better coordination of the body segments in the pitching motion not only enhances performance but also avoids injury. The coordination of motion by athletes in the pitching motion provides a guideline for better coaching and training.     

一种棒球发球机的永磁直流电机开发

通过阐述棒球发球机的永磁直流电机开发过程，介绍了生产永磁直流电机所需关键设备及仪器，总结了永磁直流电机电枢、定子、总装等各个部件的制造工艺，帮助电机制造工艺人员和生产现场管理人员掌握最新的永磁直流电机制造技术。     

锻造操作机提升俯仰系统平降下滑问题的分析

针对锻造操作机提升俯仰系统平升缸停止时刻短时下滑问题,运用AMESim软件建立液控单向阀及提升俯仰液压系统仿真模型并进行仿真分析,分析了系统中液控单向阀卸荷小阀芯、主阀芯以及控制活塞的瞬态运动特性。结果表明:油缸下滑是由于液控单向阀不能即时关闭所致,液控单向阀关闭过程中,控制活塞复位缓慢,给阀芯复位造成一定阻力,使阀芯不能立即复位。通过增大控制活塞复位弹簧的刚度可使活塞复位迅速,液控单向阀可立即关闭,有效解决油缸下滑问题。     

基于Fluent的导弹气动特性计算

借助于商业CFD软件FLUENT．对某型空空导弹在不同攻角、不同飞行马赫数的气动力进行了计算。得出了该型导弹升力系数、阻力系数和俯仰力矩系数随飞行马赫数和攻角的变化规律以及导弹表面的压力分布、温度分布和来流速度分布。结果表明。计算的气动参数可以为导弹的外形设计提供依据和参考，与传统计算方法相比有一定的优越性。     

复杂条件下大倾角对放顶煤冒放规律的影响研究

根据申家庄煤矿2208工作面具体的工程地质条件，理论分析了大倾角对顶煤冒放性的影响，指出大倾角将使工作面上、中、下部产生三种性质不同的力学结构，并通过RFPA有限元软件分别对这三种结构的冒放特征进行了数值模拟，揭示了大倾角煤层顶煤的冒放规律，对该矿优化采煤工艺、提高煤炭采出率有重要指导意义。     

湄江河湄潭县政府新区河段防洪堤设计

湄江河湄潭县政府新区河段,基本没有防洪排涝设施,每遇暴雨就产生峰高、量相对较小的洪水汇流,造成县城、大片农田及村寨发生洪涝灾害。结合工程区的地形地质、河段治理范围等条件,对防洪堤布置、防洪堤轴线选择、堤型等内容进行了详细的设计分析,尤其对堤防结构、岸坡稳定性、护坡稳定性、河道清淤进行了详细的论证研究。推荐采用技术上可行、经济上优越的浆砌石护脚、护坡结合卵石护坡+草皮护坡的防洪堤设计方案。     

THE EFFECT OF PITCHING YEAST AERATION ON THE PRODUCTION OF ACETIC ACID DURING FERMENTATIONS WITH BREWERS' YEAST: AN ENZYMATIC APPROACH

Aeration of pitching yeast signicantly increases the metabolism of acetate. This increase is particularly noticed at an enzymatic level, with special reference to the specific activity of the Fe⁺⁺⁺ linked pyruvate de-carboxylase which has been shown to be involved in the production of acetic acid. At the beginning of fermentations carried out with aerobic and anaerobic pitching yeasts, an increase in acetic acid production is observed, this is followed by reabsorption. Stabilisation in the concentration of acetic acid is observed until the end of fermentation. Initial and final concentrations of acetic acid obtained during fermentations were significantly higher in fermentations carried out with aerobic pitching yeasts than in fermentations carried out with anaerobic pitching yeasts.