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15 January 2020 Volume 33 Issue 1
  
    Design of Signal Source for Perimeter Intrusion Detection System Based on AD9910
    ZHAO Nengwu,LU Hongmin,XU Tao,HU Kuan,HE Chuanxia,MENG Xiaojiao
    Electronic Science and Technology. 2020, 33(1):  1-5.  doi:10.16180/j.cnki.issn1007-7820.2020.01.001
    Abstract ( 289 )   HTML ( 4 )   PDF (1017KB) ( 24 )  
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    Using AD9910 chip as the core of signal source frequency synthesizer and FPGA as the controller, two signal sources with their respective advantages were designed by combining hardware and software. In this way, the acquisition and output of a single carrier frequency pulse with a center frequency of 40~200 MHz and adjustable amplitude required by the perimeter intrusion detection system and its carrier were obtained. After the final test of the system, experimental data showed that the system had good stability. The spur of output signal was lower than -50 dBc, and the phase noise of the carrier was better than -60 dBc/Hz@10 kHz.

    Research on Performance Evaluation of Rolling Bearing Performance Based on SK and Other Indicators and SVM
    LI Chao,GUO Yu
    Electronic Science and Technology. 2020, 33(1):  6-12.  doi:10.16180/j.cnki.issn1007-7820.2020.01.002
    Abstract ( 184 )   HTML ( 3 )   PDF (1294KB) ( 20 )  
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    A new method for performance degradation evaluation of rolling bearings based on multiple support vector machine and indicator selection was proposed in this paper. The degree of fault at different stage in rolling bearing full life is different. In the study, fault monitoring was divided into 4 parts including normal stage, incipient stage, mid-term stage and final stage. The advantages of spectral kurtosis which was sensitive to incipient fault was demonstrated by comparing with traditional indicators such as RMS, kurtosis value and peak to peak value etc. Then, the spectral kurtosis and other indicators were selected as inputs, and the multi-class support vector machine prediction model was constructed to predict the degradation stage of rolling bearing. The prediction model was finally tested by bearing full-life test data, which verified the effectiveness and feasibility of the method and had practical engineering significance.

    Research on Robot Path Planning Based on Improved Ant Colony Algorithm
    LIU Yongjian,ZENG Guohui,HUANG Bo,LI Xiaobin
    Electronic Science and Technology. 2020, 33(1):  13-18.  doi:10.16180/j.cnki.issn1007-7820.2020.01.003
    Abstract ( 459 )   HTML ( 24 )   PDF (1371KB) ( 76 )  
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    Aiming at the problem that the traditional ant colony algorithm had slow convergence speed and easy to fall into local optimum, an improved ant colony algorithm was proposed. Based on the traditional A * algorithm, the valuation function of the traditional A * algorithm was improved. which was further introduced into the ant colony algorithm. The modified heuristic function η was proposed to increase the attraction of the target point to the path search and improve the convergence speed. The pheromone volatilization factor ρ was improved, and the pheromone volatilization factor was dynamically changed, which promoted the global search ability of the algorithm and prevent it from falling into local optimum. The simulation results showed that the improved ant colony algorithm was nearly 50% faster than the traditional ant colony algorithm in convergence rate, and was superior to the traditional ant colony algorithm in the shortest path, which proved the effectiveness of the improved algorithm.

    Study on the Surface Induced Current of Vehicles Irradiated by High-altitude Nuclear Electromagnetic Pulse
    WANG Wei,XIE Xutong,HU Kuan,WANG Wen
    Electronic Science and Technology. 2020, 33(1):  19-22.  doi:10.16180/j.cnki.issn1007-7820.2020.01.004
    Abstract ( 240 )   HTML ( 1 )   PDF (731KB) ( 20 )  
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    The induced current on the surface of vehicles under high-altitude nuclear electromagnetic pulse (HEMP) illumination is an critical problem of the electromagnetic protection of armored vehicles. The high-altitude nuclear electromagnetic pulse waveform released by IEC6100 was selected in this study to establish the simulation electromagnetic model of induced current on vehicle surface under high-altitude nuclear electromagnetic pulse irradiation. Meanwhile, the CST software based on FDTD algorithm was used for simulation analysis. Through changing the irradiation direction of HEMP and removing the gun tube, the variation of the maximum and peak areas of the induced current on the vehicle surface at different frequency points were compared and studied. Experimental results showed that the maximum induced current of vehicle surface at different angles was positively correlated with the complexity of vehicle surface structure in the irradiation direction, and the induced current in the gun barrel was much higher than that in other parts. The reference value of the maximum induced current of vehicle was 1.82×10 3 A·m -1, and the key protection frequency range was 0~40 MHz.

    Unstructured Road Detection Based on Edge Information and Maximum Entropy Segmentation
    WANG Xiang,ZHANG Juan,FANG Zhijun
    Electronic Science and Technology. 2020, 33(1):  23-28.  doi:10.16180/j.cnki.issn1007-7820.2020.01.005
    Abstract ( 216 )   HTML ( 0 )   PDF (1263KB) ( 24 )  
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    Aiming at the problem that the unstructured roads are difficult to accurately detect due to the various scene interference factors, an unstructured road detection algorithm based on the combination of maximum entropy and edge information was proposed. In this paper, the two-dimensional maximum entropy was used for the initial segmentation of the road because of the fact that the gray level of the high entropy fields of image was relatively uniform and vice versa. Furthermore, the road edge information was applied to further improve the inaccurate problem of road detection caused by uneven illumination, shadow and water stain. The experimental results indicated that the algorithm could accurately detect the road surface with light, shadow and water without the effect of the road environment and meet requirements of real-time.

    Analysis of High-altitude Nuclear Electromagnetic Pulse Impact on Vehicle Cables
    HU Kuan,XIE Xutong,WANG Wei,ZHAO Nengwu,LU Hongmin
    Electronic Science and Technology. 2020, 33(1):  29-33.  doi:10.16180/j.cnki.issn1007-7820.2020.01.006
    Abstract ( 208 )   HTML ( 1 )   PDF (973KB) ( 14 )  
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    The in-vehicle electronic equipment in complex electromagnetic environment is subject to the threat of high altitude nuclear electromagnetic pulse, in which electromagnetic effect and protection of built-in cable determine the viability and performance of special vehicles. In this paper, we used the electromagnetic simulation software CST based on FTDT algorithm to establish the electromagnetic model of the vehicle shell and the cable layout model of the vehicle, and to simulate the current and voltage response of the high altitude nuclear electromagnetic pulse in the vehicle cable. The simulation results showed that the response voltage of the twisted pair was larger while the response current was smaller. The response voltage of the coaxial line was smaller while the response current was larger. The response voltage and current of shielded cable were smaller than that without shielding under HEMP. However, there existed a slot in the actual vehicle shell, causing resonance at some frequency points in response to voltage and current, resulting in a larger value of voltage and current. The results of analysis in this paper has certain practical engineering significance for electromagnetic pulse protection of vehicle electronic equipment.

    Search Scheduling Method of Medium-speed Search Guidance Long-term Acquisition
    SUN Zelin,HU Jin
    Electronic Science and Technology. 2020, 33(1):  34-38.  doi:10.16180/j.cnki.issn1007-7820.2020.01.007
    Abstract ( 243 )   HTML ( 0 )   PDF (812KB) ( 22 )  
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    Aiming at the problem of long search time and low intercept probability of the radar signal reconnaissance system, a search and scheduling method based on airspace wide open radar signal reconnaissance system was proposed, which was able to optimize the dwell time. According to the length, dwell time was divided into medium dwell time which was only able to intercept a single radar pulse and long dwell time which could intercept multiple radar pulses. Search started with a shorter medium dwell time for fast scanning in the frequency domain. The dwell time was adjusted to a long dwell time after the signal was intercepted to acquire radar signals for frequency and periodic structure analysis. The simulation result showed that the proposed algorithm was able to make rational use of system resources and improve the interception performance of the system, which provided a useful reference for the design of existing radar reconnaissance.

    Evaluation of Code Review Comments Based on Deep Learning
    DUAN Yujia,JU Ting
    Electronic Science and Technology. 2020, 33(1):  39-45.  doi:10.16180/j.cnki.issn1007-7820.2020.01.008
    Abstract ( 290 )   HTML ( 5 )   PDF (1181KB) ( 18 )  
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    Aiming at the code review comments during the code review process may be of no value to developers, a code review comments evaluation method based on deep learning Long Short-Term Memory networks was proposed, which can effectively extract the features related to validity of the code review comments, then a code review comments evaluation model based on these features was built to judge whether the review comments are useful to the developer. In order to verify the method, the extensive experiments were conducted based on the open source Eclipse project on GitHub as experimental data, and this paper compared the method with other machine learning methods. The experimental results demonstrated that the method effectively evaluate whether the review comment is meaningful and significantly better than the comparison methods.

    Research on TSV Structure of 2.5D Silicon Interposer
    LIU Jiansong,LIN Pengrong,HUANG Yingzhuo,LIAN Binhao
    Electronic Science and Technology. 2020, 33(1):  46-50.  doi:10.16180/j.cnki.issn1007-7820.2020.01.009
    Abstract ( 335 )   HTML ( 3 )   PDF (889KB) ( 40 )  
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    Aiming at the problem that the influence of structural parameters on the reliability of TSV is not clear, the finite element analysis and model simplification method were used to analyze the stress-strain distribution of TSV structure under temperature cycling conditions. The effect of structural parameters including copper pillar diameter, SiO2 layer thickness and TSV pitch on the reliability of TSV structure were further studied. The results showed that the fitting degree of the results obtained by simplifying the model was above 0.95. When the temperature cyclic load was applied to the TSV structure, stress concentration would occur at the SiO2 interface, and strain increase would occur in the passivation layer. Changing the copper column diameter, insulation thickness and TSV pitch could significantly affect the reliability of the TSV structure. Reducing the diameter of the filled copper, increasing the thickness of the SiO2 layer, and increasing the TSV pitch all helped to reduce the maximum stress of the TSV structure.

    A AlGaN/GaN Schottky Diode with Anode Connected P-type Buried Layer
    SUN Youlei,TANG Jianxiang,WANG Ying,HUANG Yifei,WANG Wenju
    Electronic Science and Technology. 2020, 33(1):  51-56.  doi:10.16180/j.cnki.issn1007-7820.2020.01.010
    Abstract ( 258 )   HTML ( 2 )   PDF (1098KB) ( 29 )  
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    In the traditional AlGaN/GaN Schottky diodes, the anode leakage is an important factor that limits the enhancement of the breakdown voltage of the device.Therefore,aAlGaN/GaN Schottky diode structure with a P-type buried layer grown in the buffer layer and connected to the anode (AC-PBL FPs SBD) was investigated to suppress the anode leakage current. Meanwhile, field plates were added to both anode and cathode to modulate the surface electric field distribution of the device. The simulation proved that the anode leakage current of the structure was effectively suppressed, and the 2DEG in the channel was depleted. The space charge region was enlarged, and the breakdown voltage of the device was improved. The breakdown voltage of this structure was 733 V. Compared with the traditional GET SBD device, the breakdown voltage was increased by nearly 3.4 times, and the Baliga value was improved by nearly 11.6 times, indicating that the device could be applied in power electronic circuits.

    Interior PMSM Sensorless Control Based on Disturbance Observer
    HUANG Song,LI Haijian,SHI Wei
    Electronic Science and Technology. 2020, 33(1):  57-62.  doi:10.16180/j.cnki.issn1007-7820.2020.01.011
    Abstract ( 314 )   HTML ( 4 )   PDF (973KB) ( 72 )  
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    For the sensorless control of the IPMSM based on the observer in the two-phase stationary coordinate system, thereare problems including coupling of electrical angle estimation error, the cross-axis inductance and load torque, and complicated electrical angle compensation. In order to solve these problems,the sensorless control of IPMSM was carried out by using the original inductance parameters of the motor in the synchronous rotating coordinate system in this study. By establishing the vector mathematical model of PMSM, the influence of the original parameters of IPMSM on the estimation of back EMF was analyzed when the electrical angle estimation error existed. The conclusion of the method verified the theoretical feasibility of the method. The simulation was conducted by MATTSB/Simulink, and the targeted experiments were performed. The results showed that the proposed algorithm did not require electrical angle compensation, and could track the rotor position and speed of the motor under the disturbance condition.

    Motor Vibration Signal Denoising of Adaptive Threshold Function Wavelet Algorithm
    SUN Mingyang,XIE Zidian,HAN Long,BI Sida
    Electronic Science and Technology. 2020, 33(1):  63-67.  doi:10.16180/j.cnki.issn1007-7820.2020.01.012
    Abstract ( 307 )   HTML ( 4 )   PDF (969KB) ( 36 )  
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    Generally, the vibration signal of the collected motor contains noise components. The wavelet threshold denoising process can achieve good results. However, the traditional soft and hard threshold functions have the disadvantages of constant deviation or discontinuity, and the useful information cannot be well preserved. Aiming at this problem, a new threshold function with adaptive layer number and adjustment parameters was proposed. The improved wavelet threshold function was continuous, differentiable and gradual. The genetic algorithm was used to adjust the parameters and optimize the denoising based on the majority of the original signals, so that the new wavelet denoising algorithm retains useful information and removes noise. There was a good balance between the two. The method was applied to the collected motor vibration signal by experiments. The results showed that the method had higher signal-to-noise ratio and lower root mean square error, which could better filter out noise and retain useful information of the original signal.

    The Application of Gradient Descent Method in Optimizing the Dispatching Function of Reservoirs
    WANG Wei,HU Yiming,SHI Qiang
    Electronic Science and Technology. 2020, 33(1):  68-72.  doi:10.16180/j.cnki.issn1007-7820.2020.01.013
    Abstract ( 177 )   HTML ( 0 )   PDF (688KB) ( 19 )  
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    The dispatching function is a common method for formulating long-term operation scheduling of reservoirs. However, the method used to extract the dispatching function by binary linear regression usually gets poor fitting accuracy. Aiming at this problem, the optimal scheduling model with the maximum generating capacity of the reservoir during the dispatching period was established. The reservoir scheduling function coefficients of each period were extracted as the initial values by linear regression. Then the gradient descent method was used to optimize the scheduling function coefficients of each period. The inflow classification strategy was introduced in the period with poor fitting accuracy, and the optimized reservoir scheduling function was finally obtained. The calculation results showed that the effective and practical method used in the paper provided higher precision scheduling function coefficients and ensured the optimal power generation efficiency of the dispatching.

    Study on the Electromagnetic Properties of Hydrogen Induced Two-dimensional Chalcogenide PtX2
    SHI Tingting
    Electronic Science and Technology. 2020, 33(1):  73-76.  doi:10.16180/j.cnki.issn1007-7820.2020.01.014
    Abstract ( 172 )   HTML ( 0 )   PDF (855KB) ( 17 )  
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    To fully explored the potential magnetic devices application of two-dimensional heavy transition metal chalcogenide materials, the stability and the electromagnetic properties of hydrogen-induced PtX2 (X=S, Se, Te) monolayer was studied based on the spin polarization density functional theory. The results showed that the PtX2 monolayer had high stability after hydrogenation, and the stability decreases with the increase of the chalcogen atomic number. The magnetic moment of the PtX2 monolayer appears by the hydrogenation, leading to the change from semiconductor to the ferromagnetic metal. The magnetic moment mainly resulted from the spin polarization of Pt 5d electrons in the narrow anti-bond band. In addition, the ferromagnetism of the PtX2 monolayer also tended to decrease with the increase of the chalcogen atomic number. Our research provided a reference for the design of ferromagnetism of two-dimensional heavy transition metal chalcogenide materials.

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