Table of Content

15 February 2019 Volume 32 Issue 2

  

Study of Dry Etching in 4H-SiC Material

XU Longlai,ZHONG Zhiqin

Electronic Science and Technology. 2019, 32(2):  1-3.  doi:10.16180/j.cnki.issn1007-7820.2019.02.001

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Due to the stability of SiC material and the disadvantages of wet etching, dry etching is generally used to etch SiC material. However,the roughness of the etched sample surface caused by dry etching will have a certain impact on the performance of the device. In order to solve the problem, inductively coupled plasma-reactive ion etching (ICP-RIE) was applied to etch SiC material with the mixture of SF₆/O₂ and SF₆/CF₄/O₂. The effects of pressure, ICP power and gas mixture ratio on the surface roughness of the samples were investigated respectively. The experimental results showed that with use of the mixture of SF₆/O₂ , the surface roughness was improved. Under certain RIE power, when the ICP power was 700 W, the pressure was 20 mT and SF₆/O₂ was 50/40 sccm. Meanwhile, the roughness of the sample surface was the minimum.

Blur Kernel Estimation Algorithm Based on Cepstrum and Spectrum Analysis

WANG Wenkai

Electronic Science and Technology. 2019, 32(2):  4-8.  doi:10.16180/j.cnki.issn1007-7820.2019.02.002

Abstract ( 626 )   HTML ( 77 )   PDF (1181KB) ( 225 )  

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Blind image deblurring is a classical image and signal processing problem, which aims to recover a blur kernel and a clear latent image from a blurry image. In the case of fuzzy kernel estimation, the size of blur kernel in earlier algorithms is an input parameter. In recent years, some algorithms can accurately estimate parameterized blur kernel. The none-parameterized blur kernel is more usual in the natural environment, while existing algorithms can not accurately deal with none-parameterized blur kernel. In this paper, cepstrum of image gradient was used to estimate the blur kernel and spectrum was used to further estimate the blur kernel with small size. Experiments results demonstrated that the proposed method could be applied to the fuzzy kernel-scale estimation of natural blurred images in most scenes.

UAV Path Planning Based on Intelligent Algorithm

YUE Xiu,ZHANG Wei

Electronic Science and Technology. 2019, 32(2):  9-13.  doi:10.16180/j.cnki.issn1007-7820.2019.02.003

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This paper proposed a new method for UAV route planning based on K-means algorithm and Hop-field neural network algorithm, which dealt with the formation of multi UAVs under complex constraints and high coverage cruise. A digital map model of the task area was established for the no-fly zone, the target zone and the valid zone required by the mission and the model decomposition was performed to reasonably decompose the effective area into multiple sub-target points. Then the K-means algorithm was used to cluster the target points of UAV cruise, and the Hop-field neural network algorithm was used to carry out UAV trajectory planning for similar sub-target points. Taking the real data of UAV in earthquake relief as an example, the coverage ratio of 90% of the cruise area was simulated, which proved the robustness and effectiveness of the proposed method.

Master-slave Control System Simulation of Surgical Robot Based on LabVIEW

HAO Jiajun,WANG Yagang,MA Jiangtao

Electronic Science and Technology. 2019, 32(2):  14-19.  doi:10.16180/j.cnki.issn1007-7820.2019.02.004

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In order to clearly observe the motion state of the surgical robot, a method of constructing a 3D virtual simulation platform based on LabVIEW was proposed. The graphical programming software LabVIEW serving as a construction platform, combined with SolidWorks mechanical modeling, LabVIEW GUI front panel, 3D display control and LabVIEW Robotics toolkit to build a 3D virtual simulation platform for surgical robots high visualization realistic model effects. According to the self-designed master and slave mechanical arm, the process of constructing the virtual simulation platform was described in detail, and the real-time parameter control of the surgical robot in the master-slave control system was realized. Finally, the end position movement of the surgical robot was tested with MATLAB. The test results showed that the trajectory path was consistent, and the virtual simulation platform of the surgical robot could be constructed by this method.

Electrical and Optical Properties of ZnO Doped with Rare Earth Element (Sm,Tm)

WANG Yan,YANG Ping

Electronic Science and Technology. 2019, 32(2):  20-24.  doi:10.16180/j.cnki.issn1007-7820.2019.02.005

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Based on the CASTEP module in Materials Studio software, the band structure, density of states and optical properties of rare earth elements (Sm and Tm) doped ZnO were calculated and analyzed by using the first principles plane wave super soft pseudo potential method. The calculated results showed that the energy band of the doped system became thicker and denser, and the impurity energy level was presented. The Fermi energy moved upward from the top of the valence band to the conduction band. The system transformed into degenerate semiconductor, and showed stronger metallicity which prsented n type conduction. Furthermore, the changes of the absorption coefficient and the dielectric function after doping were analyzed.

Development of the Experimental Teaching Platform of Integrated Precision Manufacturing

JIANG Chen,HAO Yu,JIANG Zhenyu,YE Hui

Electronic Science and Technology. 2019, 32(2):  25-31.  doi:10.16180/j.cnki.issn1007-7820.2019.02.006

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To meet the requirement of experimental teaching in higher engineering education, a teaching experimental platform for integrated precision manufacturing was established. A five-axis machine tool and its electric control system were designed, which integrated several precision, micronano machining and detective technologies including subsystems of bonnet polishing, magnetic component fluid polishing, ultrasonic vibrator, indentation, material hardness and surface detection, material and surface damage detection to perform a variety of teaching experiment function of machining and detection.The proposed platform had the characteristics of wide application range and easy expansion, which provided a good hardware platform for education experimental teaching reform of higher engineering education and advanced manufacturing technology research under the background of ‘new engineering’.

High Precision Integral Charge Balanced Analog to Digital Converter

LIU Lian,WEI Rongshan

Electronic Science and Technology. 2019, 32(2):  32-36.  doi:10.16180/j.cnki.issn1007-7820.2019.02.007

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A high speed integral charge balanced ADC composed of switch capacitor integrator, comparator, counter and control logic unit was proposed in this paper, which was mainly applied in ambient light sensors. In general, traditional dual slope ADC could not reduce the impact of artificial light flicker noise. Meanwhile, the conversion speed of traditional dual slope ADC was also limited. The new converter adopting integral type charge balance ADC structure changed the range of analog digital converter by controlling the current of integrator access circuit under different conditions, so as to improve the simulation speed and accuracy of the overall circuit. Spectre simulation experiments showed that the simulation accuracy achieved 16 bit and the total deviation was less than 0.5%, which demonstrated the whole simulation speed got improved.

The Least Mean Square Ultrasonic Beamforming Algorithm Based on GSC

LUO Ying,WU Qiang,QIN Yun

Electronic Science and Technology. 2019, 32(2):  37-41.  doi:10.16180/j.cnki.issn1007-7820.2019.02.008

Abstract ( 546 )   HTML ( 6 )   PDF (1146KB) ( 76 )  

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In order to narrow the width of the main lobe and increase the spatial resolution of conventional ultrasonic apodization algorithm imaging method, a generalized sidelobe canceller under the framework of the Least Mean Square ultrasonic beamforming algorithm was proposed in this paper. The expected signal minimum variance distortionless criterion was adopted to design the generalized sidelobe canceller with which received ultrasonic signalsare decomposed into the adaptive parts (the upper branch) and the non-adaptive parts (the bottom branch). The distortionless desired signal and noise were reserved in the upper branch, and the noise was contained in the bottom branch. Wiener filtering method was used to filter the signals of the two parts by removing noise and exporting the distortionless desired signal. This algorithm was realized in hardware applied by adaptive iteration LMS algorithm, and the detailed FPGA implementation was designed. The simulation results depicted that the main lobe was narrower in this weighted apodization algorithm compared to the conventional amplitude apodization algorithm, and the noise and interference were suppressed to improve the lateral resolution and contrast resolution of ultrasound imaging.

Simplified Calculation Method of Jet Flame Angle and Telemetry Cloth Station Application

PANG Yuefeng,ZHANG Yue,ZHANG Qian,MA Zhanshun

Electronic Science and Technology. 2019, 32(2):  42-46.  doi:10.16180/j.cnki.issn1007-7820.2019.02.009

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Signal attenuation caused by the rocket tail flame is one of the key considerations in the design of launch vehicle and the selection of points on the ground. It is difficult for the equipment personnel to know the flight attitude of target and use the traditional method to calculate the flame angle. To solve these issues, based on the mathematical relationship between the positions of the stations, the angle of the flame and the pitch angle of the rocket during flight, a method of using the cosine of space between two vectors to calculate the included angle of the flame was proposed. The simplified method did not need to know the flight attitude parameters of the target. Compared with the traditional method, the calculated result error was less than 0.1°, which met the precision requirements of equipment station analysis. With use of the method, the signal reception affected by flame could be further estimated through calculating the angle of the flame in the target tracking process, which improved the rationality of equipment site selection.

An Improved Dictionary Learning Method for Medical Disease Analysis

LUO Chong,WU Chunxue

Electronic Science and Technology. 2019, 32(2):  47-50.  doi:10.16180/j.cnki.issn1007-7820.2019.02.010

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This paper proposed the weighted mechanism to combine the sample with the dictionary atom based on the traditional dictionary learning algorithm, which ignored the relationship between the sample and the dictionary atom. At the same time, the l₂ norm regularization constraint was adopted to avoid over fitting on coding coefficients. The paper used the leave one out cross validation to compare the accuracy, sensitivity and mean error rate of the algorithm in the depression data sets. The results showed that the improved method had a good effect on the medical disease classification. The average classification accuracy was improved by 21.87%, and the sensitivity and mean error rate also displayed good performance.

Minority Headdress Recognition Based on Convolutional Neural Network

LI Rongrui,SHI Lin,ZHAO Wei

Electronic Science and Technology. 2019, 32(2):  51-55.  doi:10.16180/j.cnki.issn1007-7820.2019.02.011

Abstract ( 475 )   HTML ( 12 )   PDF (1206KB) ( 83 )  

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The feature point of the traditional headdress image recognition method was extracted by the researchers manually. The system has some disadvantages including tedious preprocessing steps, high sample requirement and low accuracy. To solve these problems, the convolutional neural network was constructed to learn the deep features from image data. The CNN model selected the ReLU function with better sparsity to adjust the output, and used back propagation algorithm to optimize the network parameters.The softmax classifier was identified after the CNN model. The experimental results showed that the recognition rate of the system to the test set of headdress reached 96.25%. This method was proved to have good recognition accuracy and recognition efficiency.

A Busy Coefficient Based on Dual Cluster Head Algorithm of Adaptive WSN for Energy Consumption Optimization

WANG Kang,WU Chunxue

Electronic Science and Technology. 2019, 32(2):  56-60.  doi:10.16180/j.cnki.issn1007-7820.2019.02.012

Abstract ( 415 )   HTML ( 7 )   PDF (1087KB) ( 50 )  

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The communication between sensor nodes plays an important role in Wireless Sensor Network (WSN), because it affects the network lifetime. However, the communication is quite unbalanced, which may result in an increased energy consumption and decreased network lifetime. To address the problem, a busy coefficient based WSN adaptive cluster head switching algorithm was proposed. Firstly, the algorithm chose dual cluster heads, and the nodes communicated with the base station through the current cluster head and adaptively switch the cluster head according to the actual situation in network. Secondly, if its energy was less than the threshold, the current cluster head was switched to the secondary one, and the node communicated with the base station through the secondary one. Finally, the simulation results demonstrated that the proposed algorithm could improve the network lifetime by shortening the overall communication distance of the nodes, thus outperformed in both energy consumption and in network lifetime.

Design of LDO Circuit Based on DynamicFrequency Compensation

NIU Ganggang,LI Wei,LIU Wentao,ZHAI Yahong

Electronic Science and Technology. 2019, 32(2):  61-65.  doi:10.16180/j.cnki.issn1007-7820.2019.02.013

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This paper presented a LDO circuit based on dynamic frequency compensation. The LDO loop gain and transient-response characteristics were improved by adding a voltage buffer. The circuit used a current mirror to sample the current of pass transistor, making the frequency of the main pole and the third pole present the same change with the load current. With this method, the problem of loop stability caused by LDO’s zeros and poles changing with load current was overcome. Based on CETC 24 ^th Institute’s HC12 BJT technology and simulation conducted by Spectre, the LDO’s frequency characteristic under different load current was studied. The simulation results demonstrated that the LDO loop had a phase margin of 50° to 70° when load current varied from 10 μA to 100 mA, proving the good stability of the proposed LDO regulator.

Effect of Atmosphere on the Performance of Ultraviolet Detector Based on Ultrathin ZnO Nanosheets

ZHAO Shuang,ZHU Yuankun,WANG Xianying

Electronic Science and Technology. 2019, 32(2):  66-69.  doi:10.16180/j.cnki.issn1007-7820.2019.02.014

Abstract ( 341 )   HTML ( 2 )   PDF (1194KB) ( 56 )  

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The unique nanostructures of two dimensional wide band gap semiconductor materials make it an ideal material for high performance UV- detectors. However, in the practical application process,various environment atmospheres can significantly affect the performance of UV detectors. In this paper, researchers used chemical vapor deposition method to prepare ultra-thin two-dimensional ZnO nanosheets which were further utilized to fabricate UV detection devices.Placed the detection device in a closed system for testing to exclude the impact of different application environments on the test results. At the same time, the influence of different polar molecules on the properties of two-dimensional ultrathin ZnO nanosheet UV detector wereemphatically studied.The results showed that in the presence of polar molecules, the dark current of ZnO nanoviolet photodetector was reduced by 1.5~2 times while the sensitivity and response rate were increased by about 1.5 times.

An Online Scheduling Scheme for Random Event Capture in Asynchronous Sensor Networks

YU Zhixiang,CHENG Zongmao,XU Xianghua

Electronic Science and Technology. 2019, 32(2):  70-74.  doi:10.16180/j.cnki.issn1007-7820.2019.02.015

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Aiming at off-line problem of sensor node sleeping scheduling based on event random property in existing asynchronous sensor networks, Bayesian estimations were given for the distributed parameters of random variables describing random property of random events. The relationship among the instantaneous capture probability, the energy efficiency of the sensor capture event, and the Bayesian estimates was discussed to obtain the relationship between sensor's sleeping scheduling and Bayesian estimation of distributed parameters. Based on the above analysis, the real time adjustment scheduling schemes were obtained for the sensor node sleep. Finally, the study conducted the online scheduling and offline scheduling simulation experiments. Experimental results showed that compared with the offline scheduling scheme, online scheduling scheme had better adaptability.

Semi-physical Modeling of Steam Generator Based on LabVIEW and Modbus

CHEN Wei,WANG Yagang

Electronic Science and Technology. 2019, 32(2):  75-79.  doi:10.16180/j.cnki.issn1007-7820.2019.02.016

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Steam generator is one of the most important equipment of PWR nuclear power plant. The operating state of the steam generator is directly related to the safety of the entire nuclear power plant, so the modeling and simulation of steam generator is of great significance for the development of nuclear industry. This paper focused on the semi-physical simulation of PWR u-tube steam generator. By analyzing the structural characteristics and operation principle of the U-shaped steam generator, the steam generator was modeled by the modular modeling method, and the simulation data was stored in the control system. In LabVIEW software, the simulation model of steam generator in PWR nuclear power plant was established based on the mathematical model in divided control parts. The Modbus protocol was used to realize the communication between the software simulation in PC and UW500 distributed system for collecting important simulated data. The semi-physical simulation of steam generator correctly simulated the operation of steam generator, showed the change of thermal parameters in the first and second circuits of steam generator, and stored the records in the distributed system. These results proved that the semi-physical simulation model could be used not only for test research in different working conditions, but also as a teaching demonstration for nuclear power research.