Applied Mechanics and Materials Vols. 333-335

Abstract: Altitude rise result in air pressure reduces. Mason-Schamp ionic mobility equation shows that air pressure change can lead to the ionic mobility change. So a set of simple and economical ionic mobility measurement device system was designed which can simulate different altitudes. The device can measure ionic mobility of single gas or mixed gases at different altitudes. It includes that drift tube, ion source, ion gate, ion current detection system, migration gas preparation system, pressure regulating system and shield iron boxes.

Abstract: Binocular stereovision system is regularly only calibrated once, that is each camera is calibrated using a picture of the calibration pattern laid in the cross field. This methods calibration accuracy is expected to be improved. A twice calibrating method is proposed here. Each cameras extrinsic and intrinsic parameters are calibrated in different fields. The extrinsic parameters are firstly calibrated in the cross field, then the intrinsic parameters are calibrated in the close-range field. By applying the method to one binocular stereovision system built in our lab, it is demonstrated that the proposed method can improve the calibration accuracy more than 3.4dB than the once calibrating method. Its accuracy makes this novel method more suitable for high accurate target tracking application.

Abstract: In order to measure the rotating machinery fault quickly and conveniently at a construction site, a new measuring system of rotating accuracy of spindle was developed according to three point method. With summarizing the principle of error separation technique based on three point method, the function, hardware construction and software module of this module were introduced. The problem of harmonic suppression is relieved by changing the sensor arrangement. The measuring system mainly consists of three eddy current sensors ,a acquisition card and a personal computer. After a few parameters were inputted, the rotation accuracy of calculation and display could be carried out automatically on line at a construction site.

Abstract: Radar cross section is an extremely important parameter in narrowband radar application for space target detection, tracking, and identification, as well as for the purpose of threat assessment. An analysis algorism, together with related software for measured RCS data has been developed to extract information from the original data. Some analyzing methods for measured RCS data were introduced. The playback visual simulation process and data processing were elaborated, so as to handle the processing of software program. Finally the software running results were analyzed. The experiment results showed that the software could be used for the issue of analysis of measured RCS data in a reliable and systematical way. As a result, it provides us with a strong guarantee for space surveillance.

Abstract: Designed a Control Technology in Coal Handling System of Xinji Cogeneration Power Plant, the advanced nuclear scale is to measure the instantaneous flow of two coal conveyor belt, The coal plow and the belt switch signal is collected. Depending on the signal , the coal is accumulated to the different coal bunker. Two belts of coal was send to five different the coal bunker and was accumulated, this is conducive to the analysis of the economic indicators, so to achieve the purpose of power plant energy consumption.

Abstract: Heat flux measurement is important for dynamic thermal management (DTM) since it can provide more predicted information. Commercial heat flux sensors are too expensive and fragile for practical applications. Thermoelectric Cooler (TEC) based DTM provides the possibility of measuring the heat flux without additional heat flux sensor. Soft measurement of TEC heat flux has been presented via Neural Network (NN), which is suitable for identifying TEC model. NN models have been proposed by combing the classical TEC model together. The soft measurement performances with different NN models have been reported and analyzed in terms of accuracy, efficiency, and generalization capability.

Abstract: The principles of the open-ended coaxial probe technique for the measurement of permittivity are described. Measurements of dielectric properties are carried out over a frequency range from 300MHz to 50GHz, with a system comprising an Agilent E8364B network analyzer and a connected 2.2mm diameter open-ended coaxial probe. Water, methanol and salines of 0.1M, 0.2M, 0.6M are used as calibration liquids or liquids to be measured. Measured permittivities are presented and compared with those calculated from the Cole-Cole equation. It is shown that, in order to get good results, the calibration liquid should be similar to the liquid being measured in dielectric properties.

Abstract: A method of measuring the radius of circular parts by binocular stereo vision technology is proposed. First of all the interior and exterior parameters of cameras are acquired by the camera calibration technology. Then the epipolar constraint can be calculated which contains the calibrated information. The image matching which uses the epipolar constraint is done to find the matching points. The three dimensional (3D) coordinates of edges points are reconstructed through trigonometry reconstruction. At last the analytic expression of the plane in which the circle lies and the circles radius are calculated in two steps by Levenberg-Marquardt (LM) algorithm. The proposed method does not require the prior knowledge of position between the measuring plane and the calibration plane which monocular measurement needs. Experimental results show that the measurement has high precision.

Abstract: The error of displacement measurements by digital image correlation method is examined from a pratical perspective. Different from previous research, this study focuses on external factors influencing the accuracy of displacement measurement in the study of cooperative mark recognition and camera placement. Our major objectives of this research include indentificating the chief error sources and assessing their influences on the testing results. There are 5 parts in this paper. We start with a brief introduction of the necessity of analyzing the errors. After reviewing the principles of digital image correlation method, an detailed discussion of error soureces of this method is provided. Then we design a pratical experiment measuring the characteristics of a spring vibrator using the digital image correlation mesurement systems and laser displacement sensor. By comparing the results from two ways of measurment, we end the study with the conclusion that the accuracy of displacement measuring by digital image correlation method is tightly related to the choice of cooperative mark and camera intersection angle.

Abstract: A high-pressure-pneumatic mass flow control test-bed using inert medium was built in order to study the transient flow characteristic of high pressure gas feed system in ram accelerator. The structure of a new type measurement system of transient flow characteristic experiments applied to the test-bed was introduced as also. Measurement tests that high pressure gas-flow ejecting into a tank with exhaust-back-pressure through a high pressure fueling valve were conducted to ascertain the transient discharge coefficient. The results suggest that: The transient discharge coefficient increases with the inlet pressure difference of high pressure fueling valve according to polynomial law. Correlations between inlet pressure difference and transient discharge coefficient was obtained based on the experimental data. The correlation coefficient between the least square fitting curve of the correlations and experimental results reaches 0.994.The system could be used to study the change regularity of pressure and time in the fueling process of high pressure gas.