Measurement of Coarse Gravel and Cobble Transport Using Portable Bedload Traps

Portable bedload traps (0.3 by 0.2 m opening) were developed for sampling coarse bedload transport in mountain gravel-bed rivers during wadable high flows. The 0.9 m long trailing net can capture about 20 kg of gravel and cobbles. Traps are positioned on ground plates anchored in the streambed to minimize disturbance of the streambed during sampling. This design permits sampling times of up to 1 h, overcoming short-term temporal variability issues. Bedload traps were tested in two streams and appear to collect representative samples of gravel bedload transport. Bedload rating and flow competence curves are well-defined and steeper than those obtained by a Helley–Smith sampler. Rating curves from both samplers differ most at low flow but approach each other near bankfull flow. Critical flow determined from bedload traps is similar using the largest grain and the small transport rate method, suggesting suitability of bedload trap data for incipient motion studies.     

一种气体缓流流量测量用传感器的研究

本文提出了一种采用悬挂靶的流量传感器，并对其工作特性进行了理论分析及试验研究，这种传感器具有很好的低流速（流量）测量特性，并且具有易于交换量程，工作可靠等优点，试验表明，悬挂靶式流量传感器可测量流速低于１ｍ／ｓ的空气管流。     

原料空气和液氧中碳氢化合物的分析

闸述了空分生产的原料──空气和产品──液氧中碳氢化合物允许含量的标准，介绍了几个分析测定实例，并推荐了测试仪器．     

水电站"两低"运行工况的危害与分析

分析“两低”运行工况三个方面的危害，提出解决问题的措施。     

DYNAMIC VOIDAGE MEASUREMENTS IN A GAS SOLID FLUIDIZED BED BY ELECTRICAL CAPACITANCE TOMOGRAPHY

Based on the electrical capacitance tomography technique, a voidage measurement system that can implement a voidage distribution display and voidage measurement of a gas-solid fluidized bed simultaneously is developed. The back projection algorithm is selected as the image reconstruction algorithm to satisfy the requirement of voidage distribution display. Combining the Tikhnov regularization principle with the ART algorithm, a new quantitative hybrid image reconstruction algorithm is presented to implement the voidage measurement of a gas-solid fluidized bed. Experimental results show that the developed measurement system is successful. The speed of image reconstruction of voidage distribution is greater than 20 frames per second. The maximum error of voidage measurement can be less than 5%.     

电磁兼容性的设计与测量

文中首先介绍电磁兼容性的基本概念与研究领域，然后重点阐述电磁兼容性的设计与测量。     

Robust optimal stabilization of the Brockett integrator via a hybrid feedback

The problem of semi-global minimal time robust stabilization of the Brockett integrator (also called Heisenberg system) is addressed and solved by means of a hybrid state feedback law. It is shown that the solutions of the closed-loop system converge to the origin, in quasi-minimal time (for a given bound on the controller), with a robustness property with respect to small measurement noises, external disturbances and actuator noises.     

焊管飞锯测速轮跟随特性的研究

根据焊管飞锯测速轮的动力学方程，研究了测这轮的跟随特性，包括测这轮的跟随时间、测长误差及接触压力与测长误差的关系等。首次推导出测速轮的测长误差和测速轮与钢管接触压力的计算公式，为测速轮及测速机构的设计提供了理论依据。     

模糊理论在油罐测量系统中的应用

应用ＦＵＺＺＹ理论．提出了一种油罐高度测量系统自动补偿方法．这种方法能提高测量精度。本文介绍了这种方法的步骤与优点。