A study of hand grip pressure distribution and EMG of finger flexor muscles under dynamic loads

A matrix of miniature and flexible pressure sensors is proposed to measure the grip pressure distribution (GPD) at the hand-handle interface of a vibrating handle. The GPD was acquired under static and dynamic loads for various levels of grip forces and magnitudes of vibration at different discrete frequencies in the 20–1000 Hz range. The EMG of finger flexor muscles was acquired using the silver-silver chloride surface electrodes under different static and dynamic loads. The measured data was analysed to study the influence of grip force, and magnitude and frequency characteristics of handle vibration on: (i) the local concentration of forces at the hand-handle interface; and (ii) the electrical activity of the finger flexor muscles. The results of the study revealed high interface pressure near the tips of index and middle fingers, and base of the thumb under static grip conditions. This concentration of high pressure shifted towards the middle of the fingers under dynamic loads, irrespective of the grip force, excitation frequency, and acceleration levels. The electrical activity of the finger flexor muscles increased considerably with the grip force under static as well as dynamic loads. The electrical activity under dynamic loads was observed to be 1·5–6·0 times higher than that under the static loads.     

应用模拟内插法实现纳秒级精度时间间隔测量

本文阐述一种模拟内插测时法实现纳秒级精度时间间隔测量的测量原理、电路实现方案、关键技术问题及其测量不确定度的估计。     

凝析油自动计量测控系统的设计

从减小生产工况对凝析油计量的影响、提高计量精度出发,提出了一种集凝析油产量和含水率计量为一体的高精度计量方案,介绍了该自动计量系统测控电路及其软件的设计思路,现场运行与测试表明该自动计量系统原理正确、工作稳定、精度较高。     

加强技术监督，确保关口电能计量准确可靠

对关口电能计量装置的全过程技术监督管理和关口电能计量装置的现场校准工作进行了探讨。     

一个支持自动协作式测量的大规模网络测量系统

设计并实现了一个大规模网络测量系统FOX，该系统除具备较好的通用性、可扩展性特点之外，以一种安全高效的方式实现了对自动协作式测量的支持。目前该系统已经在实际网络测量中得到了应用。     

平面或曲面曲线长度测量仪的设计实现

以单片机为核心，采用光电传感技术，加之适当设计的机械传动装置，将曲线上的位移转换为脉冲；使用电池供电，设计制作了便携、滚轮式曲线测量仪，推动滚轮沿曲线运动，显示器显示测量的结果。该测量仪适用于服装设计、打板过程中对袖隆、领口等部位进行曲线长度的测量。经服装厂实际使用，完全能够满足使用要求，可以取代进口弯尺。同时，此测量仪也可以推广应用到其他领域各种曲线的长度测量。     

电阻测量方法的研究

详细分析了1kΩ～500GΩ电阻各量程的分辨率和测量电路输出信号范围，并以此为依据设计了实用的电路系统。同时给出具体的测量方法如下：首先判断电阻的范围，将放大器切换到合适的量程；放大后的电压信号经A／D转换送给单片机计算电阻值；根据各自量程的标准电阻值及其测量值之差进行动态校正。该方法消除了噪声对测量精度的影响。测试结果表明：在全量程范围内，最小测量误差为0.03％，最大测量误差为0.8％。     

后方交会法在变电站工程测量中的运用

文章对工程测量中后方交会法作了具体介绍，对后方交会点坐标公式作了理论推导。另外，就如何使用工程型计算器编写程序也作了详尽介绍，并列举了应用实例。为变电站工程测量提供了方便、快捷、准确的测算方法。     

应用影像对正法的前照灯检测技术

前照灯是汽车安全检测的重要内容之一，其检测技术在国内已经发展了十几年，但随着汽车工业的快速发展，既有的一些前照灯检测技术已显落后，不能满足新的需求。本文针对我国机动车前照灯的配光模式以及结构形式的变化，分析了传统前照灯检测方法存在的不足，提出了一种应用影像对正法的前照灯检测新技术并阐述了其定标方法。     

Field test investigation of a double-stage coupled heat pumps heating system for cold regions

This paper reports a double-stage coupled heat pumps (DSCHP) heating system, which couples air source heat pump (ASHP) and water source heat pump (WSHP) together. The system is presented for the first time in open literature with the objective to improve the working condition and heating performance of the ASHP under cold environment. A practical project in Beijing firstly installed this system and field test has been performed for one month. The test results indicate that the DSCHP system can be smoothly and efficiently used for heating in cold regions. Compared with the traditional ASHP heating system, the operating characteristics of the DSCHP heating system are greatly improved, demonstrating that the system can offer considerable application potential in cold regions.