Advanced Materials Research Vols. 301-303

Abstract: The paper proposes a novel method for online measuring the short-circuit impendence of the distribution transformers (DT). The relation expression of the short-circuit impedance with respect to the voltage and current of the primary and secondary side has been developed through the analysis of the equivalent circuit model of a transformer, in which the voltage and current of the DT is collected by 12-channel-data-acquisition unit. And the online SCI is computed by fitting the obtained voltage and current data. The simulation results and comparison illustrated that the proposed method is simpler and more efficient with high accuracy. Besides, the proposed method integrates the linear fitting technique. The simulation results based on Matlab/smulink verified the feasibility and effectiveness of the novel method for online measuring the short-circuit impendence of the DT.

Abstract: A method is described for measuring the micro impulse induced by the laser ablation. This method is based upon the torsion pendulum interferometry technique. The method measures the micro impulse through the detection of the swinging angle of torsion pendulum. The swinging angle is obtained by the laser differential interferometry. For the 10^-4~10^-7 magnitude micro-impulse, It could be the important measurement method in the research of micro laser plasma thruster (mLPT). The results of some preliminary experiments are presented with detailed reference to experiment methodology and accuracy. The measurement technique is well suited to cases seeking the measurement of mN×s magnitude micro-impulse.

Abstract: To correct the angular rate measurement error of MEMS gyroscopes for tactical missile, this paper proposes use of dynamics correspondence between the rudder control torque and the missile body attitude to build the state equation of system, which is more realistic and precise than the description for the actual missile attitude change with low-pass filter. In order to avoid errors in the linearization for nonlinear equations and reduce the filtering computation complexity, the Interlaced Kalman Filtering is applied to achieve the pseudo-linear state equation with coupling terms, which effectively reduce the computation complexity. Finally, the semi-physical simulation with the three-axis MEMS IMU and Electro-Servo verified that the algorithm significantly improved the angular rate measurement accuracy of the low-precision MEMS gyroscope.

Abstract: SAT-based automatic test pattern generation (ATPG) is built on a SAT-solver, which can be scalable is that it is able to take into account the information of high-level structure of formulas. Paper analyzes specific structure of circuit instances where correlations among signals have been established. This analysis is a heuristic learning method by earlier detecting assignment conflicts. Reconvergent fanout is a fundamental cause of the difficulty in testing generation, because they introduce dependencies in the values that can be assigned to nodes. Paper exploits reconvergent fanout analysis of circuit to gather information about local signal correlation through BDD learning, and then used the learned information in the conjunctive normal form (CNF) clauses to restrict and focus the overall search space of test pattern generation. The experimental results demonstrate the effectiveness of these learning techniques.

Abstract: This study attempted the feasibility to determine the ratio of tea polyphenols to amino acids in green tea infusion using near infrared (NIR) spectroscopy combined with synergy interval PLS (siPLS) algorithms. First, SNV was used to preprocess the original spectra of tea infusion; then, siPLS was used to select the efficient spectra regions from the preprocessed spectra. Experimental results showed that the spectra regions [7 8 18] were selected, which were out of the strong absorption of H₂O. The optimal PLS model was developed with the selected regions when 6 PCs components were contained. The RMSEP value was equal to 0.316 and the correlation coefficient (R) was equal to 0.8727 in prediction set. The results demonstrated that NIR can be successfully used to determinate the ration of tea polyphenols to amino acids in green tea infusion.

Abstract: In this paper, an approach is provided to reconstruct groundwater structures in three dimensions using well drilling data. The methodology was developed to construct the groundwater 3D model in order to better manage the groundwater production in Tanggu, Tianjin, China. At first, all the data (Fundamental geographic data, DEM, Boreholes’ tables) of the study area were organized in a geodatabase using ESRI® ArcGIS®. Secondly, 3D stratigraphy is constructed. Then, common 2D map can be instead of 3D visualization method. Finally, a groundwater 3D management system is developed to achieve the functions such as to manage, query, analyst, decision support and 3D visualization about groundwater information.

Abstract: A mathematical approach to describe phase contrast imaging is presented by means of Taylor expansion. The contrast of image of phase object is discussed by changing the absorption and phase-retarding of spatial filters at Fourier plane. A new filtering method is proposed to enhance the image contrast. Based on this approach, a phase-to-intensity image of phase object with higher contrast is got at its imaging plane. Through the image the phase can be detected directly without interferogram processes or phase unwrapping. From the mathematical approach, simulation in MATLAB programming is executed to prove the feasibility of small phase detection. The quick detection of phase may be used for applications such as studying living cells, high throughput microscopy or automated microscopy.

Abstract: Micro electro mechanical system (MEMS) has been increasingly used in military application. For the reliability and specialty of military requirements, the material of the MEMS device is supposed to be metal and the device is moveable. Lithographic, Galvanoforming, Abformung (LIGA) technology capable of producing high aspect ratio structures in metals like nickel is one of the important fabrication technologies in military MEMS. There are many moveable MEMS device like micro-gear and micro-slider producing by LIGA technology. But the moveable devices cannot behave well because of the friction effect. In this paper, an improved elastic-plastic model including roughness effects and an experimental procedure that predict the static friction prosperity of LIGA-processed nickel is proposed. Firstly, we use the 3D optical profilometer to research the surface roughness of LIGA-processed nickel, the surface heights distribution was found to be nearly Gaussian distribution. Secondly, the static friction model, the Kogut-Etsion (KE) model is adopted to obtain the static friction coefficient. Finally, a special designed static friction coefficient measurement apparatus is used to conduct the friction experiments. The results indicate that the surface roughness affects the friction and the smoother surface leads to a higher friction coefficient. Also good agreement was found between simulations and experimental results.

Abstract: Water management based on “regional objective ET” had been a hotspot in water shortage region. This article detailedly overviewed the major methods for monitoring ET through field measure and remote sensing retrieval, meanwhile application of distributed hydrological model based on multivariant checking to improve the result of remote sensing retrieval of ET was discussed. The region of Handan was chosen as a example to analyze the correlation of results of MODcycle model and remote sensing retrieval for ET calculation.

Abstract: The calibration curve of some metal tube rotameter has the characteristic of mutation. If the nonlinear least square method is still used as the method of linear correction, it will increase the measurement error and reduce the measurement accuracy. This paper presents a Division Ordinary Least Squares Method, which can reduce errors and improve accuracy. By the algorithm comparative experiment it can be proved that the method can improve the measurement accuracy.