bob手机在线登陆学报自然版

2020, 40(5): .

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2020, 40(5): .

Abstract(1588) PDF(2131)

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A Wave Plate Measurement Method Based on Magneto-Optical Modulating and Base Frequency Signal Detecting

CHEN Qiang-hua, KONG Xiang-yue, LIU Bin-chao, ZHANG Meng-ce, LUO Hui-fu, LÜ Wei-wei

2020, 40(5): 461-465. doi:10.15918/j.tbit1001-0645.2018.189

Abstract(2224) PDF(1346)

Abstract:
To improve the accu racy of phase retardation measurement, a wave plate measurement method was proposed based on magneto-optical modulating and base frequency signal detecting. Firstly, a magneto-optical modulator was placed at a suitable location of the optical path to be adjusted and to make only even harmonic components be left in the measurement signal. And then, detecting the residue of the base frequency component instead of whole spectrum signal, the phase retardation measurement of wave plate was carried out accurately. Finally, the theoretical formulae and corresponding wave plate measuring system were established based on Jones matrix. The analysis results show that, when the ambient temperature changes 0.1°, the measurement uncertainty of the system can be less than 5'. Half-wave plates (HWP) and quarter-wave plates' (QWP) measurement results show that, the measurement standard deviation is about 2'.

Design of Control Valve Structure with Adaptive Evolutionary Structural Optimization Method

TANG Teng-fei, GAO Long-long, LIAO Li-hui, XI Yi, LI Bao-ren

2020, 40(5): 466-470. doi:10.15918/j.tbit1001-0645.2018.443

Abstract(1884) PDF(2205)

Abstract:
To improve the convergence speed and the structure stability of the optimization process with traditional evolutionary structural optimization(ESO)method,a parameter adaptive algorithm was proposed based on penalty value selection and structure information,making the parameters of the ESO change with the iterative process.The analysis results of some typical numerical examples show that,the parameter adaptive ESO method with appropriate penalty value selection can solve the problems of fixed parameters and parameter selecting in the traditional ESO method,and can improve the optimization speed and structure stability in the optimization process.Applying the method to the optimization design of the control valve,results show the stiffness of the control valve can be improved by 10%,validating that this method can be extended to three-dimensional structure optimization and provided design for valve structure.

Stamping Blade Thickness Effect on Performance of Torque Converter

YAN Qing-dong, LI Xin-yi, WEI Wei, CHEN Xiu-qi

2020, 40(5): 471-476. doi:10.15918/j.tbit1001-0645.2018.459

Abstract(1967) PDF(2188)

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Based on a type of stamping welding hydraulic torque converter,a blade thickness full factor test was designed.Firstly,the main effects and the interaction effects of torque converter external characteristics were analyzed,combining with numerical simulation of flow field.The results show that,the main effects make the capableness of the torque converter descend along with the blade thickness increasing and the interaction effects of blade thickness are not obvious.And then,the numerical variation effects of blade thickness on performance were analyzed.The results show that,the increased thickness of the vane can induce a decline of the torque transmitted by the torque converter and this decline is from slow to fast.Finally,the blade thickness was optimized based on the study results.Combined with the actual thickness of the engineering board,the blade thickness was determined and a verification test was carried out.Similar to the variation of pump rotation moment with blade thickness,turbine torque decreases with the increase of blade thickness,especially in the low speed ratio region of torque converter.When the blade thickness is within 3 mm,for each increase of 0.5 mm thickness,the turbine torque value decreases by 0.5%,and when the blade thickness exceeds 3 mm,the turbine torque changes faster,and for each additional 0.5 mm,the maximum change of the pump rotation moment is about 3.8%.

Optimization Design on Linear Motor of Direct Drive Servovalve at High Temperature

MU Yu-kang, SU Qi, XU Bing, XIAN Ya-ping, JIN Li

2020, 40(5): 477-480. doi:10.15918/j.tbit1001-0645.2018.451

Abstract(1897) PDF(2209)

Abstract:
To solve the rating current falling problem of the linear motor induced by the demagnetization of permanent magnet at high temperature and the decrease of coil's cooling capacity, the material selection and structure optimization design are emphasized in the research area of linear motor. In this paper, the permanent magnet material, winding parameters, air gap structure and so on sides were focused on for the linear motor optimization design of 6 channels direct drive servovalve(DDV). Firstly, a finite element simulation model of the linear motor was established with Ansoft Maxwell software. And then, the parameters of winding structure were optimized, including the width and height of air gap structure, ampere turns of coil, considering the permanent magnet material. Finally, some simulation and experiment tests were carried out. The results show that, the high temperature resistance and output force of the optimized linear force motor can be significantly improved. The maximum working temperature can reach 200 degrees Celsius, and the driving force can over 100 N.

Analysis of Influencing Factors on Flow Pulsation of Inline Type Double Row Axial Piston Pump

ZHANG Jin, SUN Hao-qian, DOU Xu-an, KANG Shuang-qi, KONG Xiang-dong

2020, 40(5): 481-485,490. doi:10.15918/j.tbit1001-0645.2018.436

Abstract(1848) PDF(1234)

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The flow ripple has become one of the important factors that affect the performance of the piston pump.In this paper,an inline type double row axial piston pump was designed based on the study results of flow ripple,and the flow equation of the double row axial piston pump was established.With the different plunger parameters such as plunger size,number,and distribution,the flow ripple was calculated and analyzed,and the flow pulsation change rule of the double row axial piston pump was obtained.Taking the low non-uniform coefficient of flow as the optimization objective,the plunger parameters of the piston pump with the minimum flow pulsation were obtained,laying a theoretical foundation for the design of the inline type double row axial piston pump.

Research on Intelligent Flow Control Method Based on Proportional Directional Valve

WANG Run-lin, XU Bing, WANG Di, ZHANG Chun-feng

2020, 40(5): 486-490. doi:10.15918/j.tbit1001-0645.2018.450

Abstract(1908) PDF(2106)

Abstract:
With the continuous improvement of sensor technology and intelligent technology,intelligent proportional directional valve with built-in pressure sensor and temperature sensor are emerging. However,due to the large volume and slow response of the flow sensor,the flow sensor is difficult to be integrated into the proportional valve,so the flow information needs to be obtained indirectly by calculation. The traditional calculation method usually applies the empirical formula to the valve port flow coefficient. However,the proportional directional valve used in this study has a more complicated valve port shape and flow channel,which has a great influence on the valve port flow coefficient,and the traditional method is difficult to be directly applied. Therefore,the pressure sensors and the spool displacement sensor are used in this paper. The flow is calculated using the look-up table method and the flow feedback control is performed. This method can realize the flow dynamic control function of the proportional directional valve,thereby improving the versatility of the proportional directional valve.

Nonlinear Modeling and Simulation on Electro-Hydraulic Servo Systems with Stochastic Vibration Control

FU Bo, XIE An-huan, ZHAO Chun-yu, ZHOU Hua

2020, 40(5): 491-495. doi:10.15918/j.tbit1001-0645.2018.474

Abstract(1875) PDF(2107)

Abstract:
A nonlinear mathematical model was established on electro-hydraulic servo system with stochastic vibration control in order to reproduce reference acceleration power spectrum density (PSD) of 5~500 Hz frequency range accurately. The state dependent riccati equation(SDRE) technology was introduced to acquire system state feedback of variable gain and expand system bandwidth, considering the influence of pressure flow characteristic and servo valve control dead zone. Meanwhile the PSD equalization method was applied to modify the input signal in the frequency domain. According to the analysis in Simulink, the steady fluctuation range of PSD is within±1 dB.

Analysis on the Thermal Deformation of Fuel Electro-Hydraulic Servo Slide Valve

JIA Tao, ZHENG Shu-wei, GENG Wei, ZHANG Jin

2020, 40(5): 496-500. doi:10.15918/j.tbit1001-0645.2018.444

Abstract(1866) PDF(2227)

Abstract:
To analyze the stuck-on phenomenon of the servo valve slide valve in wide temperature operating conditions, a three-dimensional model was established for temperature field simulation based on the Solidworks software. Synchronously, a coupling field of thermal and structural analysis was established on the Ansys workbench platform to simulate the temperature field distribution of the electro-hydraulic servo valve side valve and the thermal deformation of the valve sleeve and the valve core under high temperature conditions. Analysis results show that, when the oil temperature drops, the heat transfer is in the form of ring in the valve body, inducing the variation of the radial clearance between valve core and valve sleeve. Also the analysis results provide a variation law of the radial coordination gap between the valve core and the valve sleeve along with the temperature change.

Air Compression Method Based on Isothermal Piston Heat Exchange

XU Wei-qing, DU Zi-yue, WANG Xiao-shuang, CAI Mao-lin, SHI Yan, YAN Hong-juan, WANG Jia

2020, 40(5): 501-506. doi:10.15918/j.tbit1001-0645.2018.458

Abstract(1900) PDF(2088)

Abstract:
Compressed air energy storage also has shortcomings of low energy storage efficiency and long payback period. At present,most compressed air energy storage systems use adiabatic compression. When the compressed air is compressed,a large amount of power is consumed into heat. In this paper,a method was proposed,using the isothermal piston to absorb the heat in the compressed air and discharge the heat to the liquid at the bottom of the cylinder. Firstly,a dimensionless mathematical model of isothermal piston cooling was established. Then the dimensionless coefficientsK_aandX_uaffecting the heat transfer of isothermal piston were proposed and its influence on the isothermal piston compression system was analyzed. Finally,an example calculation was made with aluminum foam to form an isothermal piston,compression ratio of 7,speed 1 200 r/min,compression efficiency can be increased 11%.

Design and Experiment of Outer Wall Cleaning Machine for Convection Section

LI Shou-zhong, LI Hai-tao, LIU Ping-yi, LIU Kai-kai, TAI Jian-jian, YANG Ya-fei

2020, 40(5): 507-511,580. doi:10.15918/j.tbit1001-0645.2019.050

Abstract(1900) PDF(2153)

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To solve the problems of energy waste and hidden danger caused by ash in the convection section of chemical equipment, a washing machine was designed with walking, guiding and over obstacle functions on the furnace tube. The washing machine was also designed to carry a spray bar and to be able spray high-pressure water, cleaning the outer wall of the furnace tube. The spray bar was arranged to be freely adjusted to achieve full cleaning the outer wall of multi-furnace tubes in different layers. According to the structure of the washing machine and the work process, a control system was designed for the washing machine. The dynamics simulation of the washing machine was carried out, and the design parameters of the washing machine were optimized. A test platform and the prototype were built. Experiment results show that, the cleaning machine can run smoothly, and the furnace tube cleaning operation can be realized with the installed high-pressure water jet.

A Sparse Feature Extraction Method Based on Improved Quantum Evolutionary Algorithm

YU Fa-jun, LIU Yi-cai

2020, 40(5): 512-518. doi:10.15918/j.tbit1001-0645.2018.225

Abstract(1840) PDF(2139)

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Feature extraction is the key to pattern recognition. Sparse decomposition can be used to express a signal as a combination of atoms with certain structural features, being an effective way to extract the internal feature information of the signal. A sparse feature extraction method based on improved quantum evolutionary algorithm (IQEA) was proposed based on the parallelism and global search ability of IQEA to achieve fast and accurate sparse decomposition of signals on an over-complete atom dictionary. Firstly, the atoms in the dictionary were coded with probabilistic amplitudes of quantum bits, and updated by evolution-mutation cross operation of quantum bits. And then, taking the inner products of signal residual and atoms as the objective function of quantum evolution, the most characteristic atoms with signal structure were selected, and the feature extraction of signals was realized based on sparse reconstruction. Finally, the feature extraction of simulation signal and fault bearing vibration signal were carried out. The results show the effectiveness and superiority of the proposed method.

Study on Effect of Annealing Process on Thermo-Mechanical Reliability of Cu Through Silicon Via (TSV) Structure

DING Ying-tao, CHEN Zhi-wei, CHENG Zhi-qiang, WANG Yi-ding

2020, 40(5): 519-525. doi:10.15918/j.tbit1001-0645.2018.118

Abstract(2327) PDF(2255)

Abstract:
In this paper, a finite element analysis method was used to study the influence of annealing process on the thermo-mechanical reliability of Cu through-silicon via structure. Firstly, the processing technology of TSV structure with polyimide (PI) dielectric layer was introduced. Then, Von Mises stress distribution and Cu protrusion height of TSV structure, which used PI and SiO₂as the dielectric layer respectively, were compared under 400℃ for 30 min. On this basis, the parameters of PI-TSV were analyzed further, including size parameters of TSV(the thickness of dielectric layer and TSV diameter, height, pitch) and annealing process parameters (annealing temperature and time). The results show that, compared with SiO₂-TSV, PI-TSV structure possesses better thermo-mechanical reliability after annealing, and it is an effective method for the Cu protrusion height and thermal stress reduction to appropriately increase the thickness of PI dielectric layer.

Design of Low-Power Successive Approximation Register Analog-to-Digital Convertor Based on a Time-Domain Comparator

ZHANG Lei, YANG Chen-chen, WANG Xing-hua

2020, 40(5): 526-530. doi:10.15918/j.tbit1001-0645.2018.087

Abstract(2092) PDF(2178)

Abstract:
In this paper, a 10 bit low power successive approximation register analog-to-digital converter (SAR ADC) was presented based on a time-domain comparator in 90 nm CMOS. Compared with conventional dynamic comparator, the time-domain comparator was arranged with differential multi-stage voltage controlled delay lines to convert voltage to time signal, and the time difference was sensed by a phase detector to reduce influence of common-mode various and static power consumption. And a partial monotonic switching strategy was employed to convert voltage in capacitor array, cutting down total capacitance and power consumption. Simulation results show that, with 1 V power supply, 308 kS/s at Nyquist sampling rate and 0.9 V signal scope, the ENOB can achieve 9.45 bit with 13.48 μW power consumption.

Optimal Design of Two-Dimensional Sparse Array Based on Mutual Coupling Reduction

LUO Xue

2020, 40(5): 531-536. doi:10.15918/j.tbit1001-0645.2018.522

Abstract(1836) PDF(1208)

Abstract:
A new planar sparse geometry, referred to as the sparse H array was proposed by re-optimizing the sensors of open box array (OBA) based on difference co-array concept. The new structures has the same number of identifiable sources as the OBAs. It can decrease the mutual coupling effect between sensors by effectively reducing sensor pairs with closed space. Simulations of the direction-of-arrival estimation verify the better anti-coupling capability of the proposed PSAs than other geometries with the 2-D unitary ESPRIT algorithm used.

A Modified Approach to Digital UQPSK Carrier Synchronization

GAO Fei, XIA Xin-yuan, HAN Xiao-dong

2020, 40(5): 537-542. doi:10.15918/j.tbit1001-0645.2018.180

Abstract(2007) PDF(2194)

Abstract:
The approach to UQPSK carrier synchronization is widely used in digital satellite communication and UAV transmission of ground and tracking system. But it is hard to realize the related recovery modes for only analog signals or complex loop. So a modified approach to UQPSK carrier synchronization was presented based on decision feedback phase locked loop (PLL) with the constellation characteristics of UQPSK signal. The approach was arranged to be implemented quickly for phase compensation and fast phase capture with fast convergence speed under the condition of low signal-to-noise ratio. The simulation and analysis results of UQPSK carrier synchronization system show that the BER of the approach to UQPSK carrier synchronization is similar to the theoretical BER, and there is the high reliability in system.

Anti-Intermittent Sampling Repeater Jamming Method Based on Stepped LFM Joint Time-Frequency Analysis

ZHANG Jian-zhong, MU He-qiang, WEN Shu-liang, LI Yan-bing

2020, 40(5): 543-551. doi:10.15918/j.tbit1001-0645.2018.202

Abstract(2035) PDF(2211)

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Analyzing the principles of the ISRJ and the characteristics of the discontinuous retransmission and sampling of ISRJ in time domain, an anti ISRJ method based on stepped LFM joint time-frequency analysis (JTFA) was proposed. This method was designed to utilize the sub pulses' orthogonality to cover each other, to extract the discontinuous retransmission signal segment with short time Fourier (STFT) in time domain, and taking the maximum signal of this segment as threshold to process the interferences suppression in time-frequency matrix. Through inverse STFT, the time domain signal could be obtained for target detection. Theoretical analysis and experimental results show this method can carry out anti ISRJ with different patterns, maximize the undisturbed signal.

Sliding Spotlight Mode Design and Slant Range Model for Elliptical Orbit SAR

LI Li, LI Cai-pin, HE Ming-yi

2020, 40(5): 552-561. doi:10.15918/j.tbit1001-0645.2019.235

Abstract(2043) PDF(2133)

Abstract:
Focusing on the characteristics of large eccentricity, time-varying orbit height and satellite speed in elliptical orbit SAR, the sliding mode design was studied for large elliptical orbit SAR. Firstly, considering different resolution improvement factors at different orbital positions, ground beam footprint consistency, antenna scanning angle, antenna scanning angular velocity and so on, a sliding spotlight mode was designed for large elliptical orbit SAR. Then, the slant range model of gliding spotlight mode echo was studied. Finally, a simulation validation was carried out. The simulation results show that the parameters of sliding spotlight mode for elliptical orbit SAR need to be adjusted with the change of orbit position. In order to meet the imaging requirements, the slant model needs to be expanded to third order.

Error Repair Technology of Lempel-Ziv-Welch (LZW) Compression Data

WANG Gang, PENG Hua, TANG Yong-wang, JIN Yan-qing

2020, 40(5): 562-569. doi:10.15918/j.tbit1001-0645.2018.141

Abstract(1766) PDF(2145)

Abstract:
Lossless data compression systems are prone to transmission errors, and the effect of bit errors presents a spreading trend as the decoding progresses, which limits its applicability in the areas such as noisy wireless channels and file systems that may be damaged. Lossless data compression algorithm LZW can be widely used in file formats such as GIF, PDF, and TIFF. In this paper, the redundancy of the LZW compressed data was used to propose a design scheme of the error repair algorithm, and present the relevant theoretical basis. This scheme was arranged to be compatible with the standard LZW algorithm, meaning that the files compressed by the proposed scheme could still be decompressed by the standard LZW decoder. Experimental results verify the feasibility and effectiveness of the algorithm.

Cell Dynamic Morphology Characterization and Classification Based on Local Temporal Feature

LI Heng, PANG Feng-qian, JIANG Bin, LIU Zhi-wen

2020, 40(5): 570-575. doi:10.15918/j.tbit1001-0645.2018.122

Abstract(1877) PDF(2159)

Abstract:
Cell morphology is often used as a proxy measurement of cell status to understand cell physiology. Hence, the interpretation of cell dynamic morphology is a meaningful task in biomedical research. Mouse lymphocytes were collected to observe the dynamic morphology, and two datasets were thus set up. Local temporal feature was proposed to consider spatial heterogeneity and temporal regularity of cell dynamic morphology. The local temporal feature was applied to the video data of cell dynamic morphology, and compared with existing methods. Experiment results show that, the local temporal feature can outperform the existing methods and provide remarkable advances in the accuracy and robustness of the classification on both datasets.

Applications of Jacobi Matrices in Kinematics of Robots

AUNG Naing-win, ZHANG Shi-qiang, CAO Yue-qi, SUN Hua-fei

2020, 40(5): 576-580. doi:10.15918/j.tbit1001-0645.2017.168

Abstract(1896) PDF(2077)

Abstract:
In this paper, an inverse kinematics issue of robot was studied based on the properties of Jacobi matrices. Especially, the cases with the redundancy and singularity of the matrix were investigated. Firstly, a method was proposed to solve the inverse kinematics. Then its applications were presented. Finally, some simulation experiments were carried out. The results provide a basic method for the programming and control of robot action.

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