Advanced Materials Research Vols. 765-767

Abstract: This paper develops a relative position and velocity estimation approach for spacecrafts in proximity. A dynamical model is built at first to describe the relative motion between the chaser and target. In this approach a light detection and ranging (LIDAR) system is used to perform the range and angle measurements of the target relative to the chaser. The three-axis magnetometer (TAM) and gyro are installed on the chaser to measure the chasers attitude. An extended Kalman filter (EKF) is designed to estimate the relative state by combination of the measurements and dynamical model. Numerical simulations prove the validity of proposed filter.

Abstract: In this paper, we propose a reliable spectrum sensing strategy based on multiple-antenna technique, called RSS-MAT, to combat the channel uncertainties. We derive the closed-form expressions of the false alarm probability and detection probability for RSS-MAT. Finally, we present simulation results to validate our performance analysis. As expected, the simulation results show that RSS-MAT outperforms the spectrum sensing strategy with single antenna.

Abstract: The bus system has the characteristics of "information sharing", the traditional automotive electrical troubleshooting techniques are difficult to competent vehicle bus system fault diagnosis. As a diagnostic method worked out in practice, chart comparison method can identify the reasons for the failure of the vehicle bus system quickly and accurately, has a certain value. By real vehicle bus system failure case, this article describes how to use the chart comparison method.

Abstract: To circuit system with a transition state from normal to fault, this paper presents "sub-health" concept to describe it, and the experiments add sub-health diagnosis type. To problem of diagnosis difficulty caused by data overlapping due to tolerance existing in analog circuits, characteristic layer fusion method is selected for feature extraction, and put forward the distance evaluation factor for feature selection. Then potential energy function classification is adopted to diagnose faults, and principle of binary tree is combined with potential energy function classification to solve multiple classification problems. The experiments adopt BP neural network to compare and verify that the method proposed is effective. The results fully illustrate that characteristic layer fusion method can extract fault features effectively, distance evaluation factor has achieved a good dimension reduction effect, and improved potential energy function classification realizes soft fault diagnosis accurately.

Abstract: The capability of space debris observation system using radio telescope was analysed in the present paper. The special bi-static observation system includes radar and large radio telescope. Detectable range of fixed RCS targets and detection ability of small space debris at fixed range were discussed respectively. The simulations of this particular observation system were implemented. The simulating results were approximately correct comparing with the actual Effelsberg experiments. The analysis of this paper gives a theoretical basis of space debris observation by domestic large radio telescope.

Abstract: Deep level transient spectroscopy (DLTS) and photo induced current transient spectroscopy (PICTS) are commonly used methods for the identification semiconductor impurities and defects. In this paper, a measurement system of DLTS and PICTS has been developed by LabVIEW. A series of different instruments construct this systems hardware (signal generator; current amplifier; capacitance meter; oscilloscope,etc.) while software is also easy to program by LabVIEW. This system demonstrates high generality for both DLTS and PICTS, and data acquired can be stored or read in computer. By contrast, it is much lower cost comparative to commercial DLTS or PICTS system. Testing result of silicon P+N junction coincides with semiconductor theory research.

Abstract: The force transducer for dynamic calibration in absorber dynamometer is usually statically calibrated. To solve the problem, a new kind of dynamic calibration device and its working principle is discussed. Furthermore , the principle of its core member, linear damper, is particularly analyzed. Moreover dampers in different structures are discussed in depth and the production of its damping force is deduced. Thus, the theoretical premise of dynamic calibration device and linear damper is provided in this essay.

Abstract: This research proposes a novel wireless RFID-based thermal convection type inclinometer design. Five new ideas are presented. The first one is to make the device on a flexible substrate, thus it can save more energy than the traditional silicon. The second one is to integrate both an inclinometer and a wireless RFID antenna on the same substrate, such that it is very convenient for usage. The third and the fourth ideas are to fill xenon gas in the chamber with hemi-cylindrical shape instead of the previous one with carbon dioxide and rectangular shape. Because the xenon gas would not produce oxidization effect to the heater, and it is more reliable. Besides, the xenon gas can increase the gas molecular weight and the device sensitivity. The fifth idea is to use non-floating structure instead of the floating one with a cavity in the substrate. Moreover, to increase the sensitivity the thermisters were stacked on one material such as alumina nitride. Note that the sensitivity curves by applying the non-floating structure with stacking material are more linear. Three kinds of stacking height were studied, such as 1, 1.5 and 2mm. One can see the combinations of AlN/Xenon are always better. If the largest sensitivity is the key consideration, then H2=1.5mm is the best choice (0.4°C/Degree), but the linear operating range is 45°. However, If the largest linear operating range is the requirement, then H2=2mm is the best one (75°), but the sensitivity is 0.173°C/Degree.

Abstract: The synchronization method based on the sound and magnetic makes power cable precise positioning more intuitive in this paper,which based on the pre-positioning of the cable fault an accurate fault location method.First the pulse generator discharges pulse applied to the cable, the fault point will release the sound signal and an electromagnetic signal. But the electromagnetic signal propagation speeds approaching the speed of light instantaneously reaches the point of failure.when the electromagnetic signal is detected , the microcontroller timer T1 is informed. T1 starts counting until up to the sound signal is detected. the LCD will display the counting result, and along the cable to we will find the minimum point of the time value ,which is the location of the fault point.

Abstract: To on-line forecast faults in batch processes, we introduced integrated models combining MPCA and ARMA. Time series of T² and SPE statistics obtained from MPCA models based on variable cross-correlations are employed to build univariate ARMA models in terms of their auto-correlations, predicting the h-step-ahead values implying process dynamic behaviors. The integrated models not only take advantage of both powerful data compression and prominent prediction ability, but also improve the performance of MPCA based process monitoring as well as trend forecasting, which are of great significance to ensure safe and smooth running of batch processes. Finally, experimental studies consisting in fed-batch penicillin benchmark problems demonstrate the effectiveness and potentials of the contributions.