Advanced Materials Research Vols. 718-720

Abstract: In a kind of large test system, the whole equipment is constituted of many multiple subsystems. These subsystems become one by the interconnection. During the measuring and calibrating procedure for the test system at the outdoor training venue, there are several multiple pulse sequence signals amplitude and cycle period need to measured, because of the complexity of the system composing structure and the ever-changing for practical training environment, the signal being measured is often subject to strong noise interference. In order to ensure the accuracy and reliability of the measuring results, thus we can provide effective and reliable data reference for the effectiveness of the equipment systems, we must do in-depth analysis for actual interference, and to take effective method to suppress the interference.

Abstract: The application of a variety of high-tech equipment, greatly improve the execute effectiveness of the equipment system. It plays a decisive role that internal parameters of the device is accurate or not, for the normal function used of these complex instrument systems. The importance of maintenance and calibration process for the test equipments accuracy must be reliable and accurate is increasingly obvious. The common mode noise suppression in equipment measurement and testing process is often encountered and must be solved in related field.

Abstract: The application of a variety of high-tech equipment, greatly improve the execute effectiveness of the equipment. It plays a decisive role that internal parameters of the device is accurate or not, for the normal function used of these complex instrument systems. The importance of maintenance and calibration process for the test equipments accuracy must be reliable and accurate is increasingly obvious. The series mode noise suppression in equipment measurement and testing process is often encountered and must be solved in related field.

Abstract: In GBAS, multipath and RFI/noise are air-ground irrelevant errors, and they could not been removed by the pseudorange difference between the aircraft and ground station. In the paper, the relationship between the B value and air-ground irrelevant error is analyzed. Since the B values for all the ground receivers are not independent, an assistant value named C is employed. Combining the characteristics of the pseudorange corrections matrix, a new method on GBAS air-ground irrelevant error monitoring is proposed. However, the method could not distinguish between multipath and RFI. Fortunately, previous study has proposed a method for detecting RFI through integrity monitoring at a DGPS reference station. Assuming the serious multipath and RFI will not appear simultaneously, user could ascertain it is multipath or RFI causes the air-ground irrelevant errors to exceed the threshold. Simulation results validated the utility of the proposed monitor methods.

Abstract: Measurement uncertainty in the water content test for soil samples is an index for evaluating the reliability of the experiment. It affects the accuracy of some parameters such as porosity and saturation, which are derived from water content. According to the requirements of the standard JJF 1059-1999 Uncertainty Evaluation and Denotation of the Measurement Results, the uncertainty for the measurement results of the water content in soil samples was evaluated. Concerning the characteristics of the water content determination in soil samples, a pail of soil sample was taken as specimen due to its relative homogeneity. The factors affecting the measurement accuracy were discussed. The result shows that the expanded uncertainty of measurement results of the water content in soil samples was 1.6% under the proposed testing conditions.

Abstract: Non-driven structure silicon micromechanical gyroscope can sense rolling, pitching and yaw angular rate of the rotating body at the same time, which is suitable for rotating body gesture detection. But this characteristic is not suitable for non-rotating flight carrier. So this study uses micro motor to provide spin angular velocity for non-driven silicon micromechanical gyroscope, and to further generate gyroscopic effect which is sensitive to the attitude information, including rolling rate, yaw angular rate and pitch angular rate of low-speed rotating or non-rotating object. The study analyses the output signals based on simulation rotating object experiments of three-axis moving of silicon micromechanical gyroscope, the study uses phase based method to determine deflection polarity, and uses double accelerometer multiplication algorithm to demodulate the output signals of gyro. All above results provide a basis research results for further realize the goal of real-time demodulation of gyro signals when silicon micromechanical gyroscope is applied to the non-rotating and rotating flight carrier.

Abstract: In order to solve the problem of containing noise in echo signal detected by electromagnetic ultrasonic metal plate thickness, wavelet threshold method was used for de-noising. First to choose the wavelet function and decomposition scale to decompose the echo signal, then structure threshold rules by the weighted average method and dispose the wavelet coefficient obtained by decomposition, reconstruction signal. De-noising signal acquired by MATLAB simulation had obvious effect and SNR was 9.4441, RMSE was 0.2. Experimental results show that wavelet threshold value method can effectively inhibit noise doped echo signal and improve electromagnetic ultrasonic detection accuracy.

Abstract: In order to solve the need of the oil and gas pipeline defect quantification in the real-time online defecting, magnetic flux leakage inspection method was applied to oil and gas pipeline inspection. According to the basic theory of the electromagnetic field, finite element solution of electromagnetic field and ANSYS electromagnetic field calculation theory, using the function of ANSYS 's simulation and calculation for magnetic field, three-dimensional finite element model of the oil and gas pipeline defect was built up. Through simulating, the relationship between defect signal and defect size was found, the optimal distance of the hall sensor lift-off value was verified, the best magnetization of leakage magnetic field was discussed, and various factors to influence the magnetic flux leakage signal is analyzed.

Abstract: A new signal processing algorithm based on a Wavelet Transform is proposed for time delay estimation in acoustic elastography. The proposed estimator using correlation coefficient as a measure of the similarity of the two signal waveforms are reasonable. And we select the wavelet function most similar to the simulated ultrasonic signal as the mother wavelet. The practical simulation shows that the algorithm offers higher noise suppression capability and is able to implement ultrasonic signal time delay estimation.

Abstract: Low-field nuclear magnetic resonance (LFNMR) is a rapid, nondestructive analytical method which has been proved to be attractive for its application in brittle and easily compressed coals. In this paper, the relationships between NMR parameters and coal pores were analyzed by the NMR measurements of six coal samples with different ranks using AniMR with the resonance frequency of 12.15MHz. Results show that NMR porosity usually compare well to water porosity and be lower than He porosity, and the NMR porosity at echo spacing of 0.3ms sometimes underestimates the coal sample, lower than water porosity by >1 porosity unit. In contrast, the NMR porosity at echo spacing of 0.1ms is acceptable for characterization of coal reservoir. The difference of NMR porosity at different echo spacing may relate to the vitrinite content. Based on the T_2c model, the transverse surface relaxivity of coal is calculated and it ranges from 0.25 to 20 um/s, commonly lower than 5um/s. The producible porosity could be a parameter used to estimate coal permeability, however there still needs a lot of work to construct a perfect method for this.