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2019 Vol. 40, No. 5
Published: 2019-09-22
 
749 Precision Measurement of Microwave Power Using Rydberg Atoms
ZHANG Jie,SONG Zhen-fei,LI Jun,ZOU Hai-yang,ZHANG Wan-feng,LIU Zheng
DOI: 10.3969/j.issn.1000-1158.2019.05.01
A new power measurement method based on the quantum coherence effect of Rydberg atoms is proposed. The low electromagnetic perturbation atomic vapor cell containing rubidium vapor is placed in the specific waveguide system. Based on Rydberg atomic quantum coherence effect, the guided wave electric field measurement is transformed into the detection of atomic absorption spectroscopy. A completely new microwave power measurement traceable to Planck constant and frequency measurement is realized by using the analytic quantization relationship between the power and the guided wave electric field. Compared with traditional power measurement at the frequency of 10.22GHz, the average deviation from -40dBm to -20dBm is 0.08dB (1.86%). The new microwave power quantum measurement method has the advantages of high sensitivity, large dynamic range and small measurement uncertainty. It is expected to form a new generation of microwave power standard that can lead to a direct SI-traceable approach for power metrology.
2019 Vol. 40 (5): 749-754 [Abstract] ( 493 ) HTML (1 KB)  PDF (1181 KB)  ( 993 )
755 The Two-dimensional DOA Estimation Base on the L-shaped Array
ZHANG Zhi-wei,TAO Jian-wu,SUI Yi-xiang
DOI: 10.3969/j.issn.1000-1158.2019.05.02
The traditional two-dimentional DOA estimation can estimate the less number of signals, and have high computational complexity, so based on the L-sparse array, the two-dimensional DOA estimation method was proposed. The method is that co-even array (CEA) placed on the L-shaped array form the virtual array to increase the array freedom; By dividing the virtual array into several equally spaced sparse subarrays, to compress the search range of angle and reduce the computational complexity consequently. By MUSIC searching, spectral peaks were obtained, and employing the maximum-likelihood criterion, the elevation and azimuth of incident signals were chosen, and through maximum-likelihood angle pairing method to pair angle between elevation and azimuth lastly. The algorithm enable estimate the number of signals more than the number of actual physical matrix, what’s more, it can increase the estimation precision and reduce the computational complexity. The results of MATLAB simulation verified the validity of this method.
2019 Vol. 40 (5): 755-759 [Abstract] ( 319 ) HTML (1 KB)  PDF (804 KB)  ( 245 )
760 Research on 110 GHz Traceable Multi-TRL Calibration Standard Based on On-wafer GaAs
YUAN Si-hao,LIU Xin-meng,HUANG Hui
DOI: 10.3969/j.issn.1000-1158.2019.05.03
To study the technique of on-wafer self-calibration, a GaAs-based Multi-TRL calibration standard kit on coplanar waveguideis is developed. It can be used for measurement system of on-wafer scattering parameters from 1 GHz to 110 GHz. The design of the calibration kitis is demonstrated and shows that good agreement with foreign commercial calibration kit and metrological calibration reference material.
2019 Vol. 40 (5): 760-764 [Abstract] ( 326 ) HTML (1 KB)  PDF (1884 KB)  ( 316 )
765 Improved Threading Method for Caliper Image Recognition
DING Shuang,REN Guo-ying,ZHANG Fu-min,FAN Nai-yin
DOI: 10.3969/j.issn.1000-1158.2019.05.04
In order to improve the digital recognition efficiency and precision of caliper display, a digital caliper image recognition algorithm based on improved threading method is proposed. The traditional threading method in the digital image recognition of the digital image with vertical tilt has poor practicality and defects frequently, it cannot be widely promoted in the intelligent manufacturing site. To solve this problem, Radon transform is first used to estimate the vertical inclination a angle of digital image, and then the slant line of the estimated angle is used to replace the traditional vertical line of the threading method, so as to realize efficient recognition through digital image segmentation and processing. Experimental results show that the recognition rate of this algorithm is 98%, which can meet the requirements of high density digital image recognition in industrial measurement.
2019 Vol. 40 (5): 765-769 [Abstract] ( 368 ) HTML (1 KB)  PDF (913 KB)  ( 369 )
770 Research on Measurement for Roundness of Microspheres Based on Micro-vision
CHEN Hou-rui,CAI Xiao-yu,WEI Jia-si,LI Yuan,YU Zhi-hao
DOI: 10.3969/j.issn.1000-1158.2019.05.05
The microscopic vision technology is used to automatically detect the roundness of microspheres with the optimization algorithm. The grabbed image of microsphere is acquired by the charge coupled device (CCD) of measuring microscope. The image is enhanced based on the principle of maximum information entropy. There is a algorithm is used to split image which proceed non-maximum suppression of the gradient and iterative. Then the roundness of microspheres by using least square circle fitting is obtained after trace pick-up. The method avoids the loss of some information of the image edge and the reduction of detection accuracy due to filtering processing. By measuring the roundness error of 0.5mm microspheres, it is proved that the method of edge detection and trace pick-up can effectively suppress the influence of noise interference and achieve the accurate location of the target edge. The relative error between the roundness of microspheres obtained by this method and the one of calibrated microspheres is within 0.17%, which could achieved the purpose of effective detection of roundness.
2019 Vol. 40 (5): 770-775 [Abstract] ( 371 ) HTML (1 KB)  PDF (1122 KB)  ( 423 )
776 Optical Path Multiplication Measurement Based on Error Elimination Principle
LIU Hong-guang,LI Qing,LI Ling-mei,CHEN Jie,LI Jun-feng,LU Rui-jun
DOI: 10.3969/j.issn.1000-1158.2019.05.06
Aiming at the problem of traceability of large-size laser ranging instruments, a long-distance measurement method based on error elimination principle of optical path multiplication was studied. A measurement model with error elimination characteristics was established. The system achieved four times the optical path multiplication. It has the advantages of simple structure with double range, high measurement accuracy, good measurement stability and continuous measurement. The virtual length baseline of 13m in the room was repeated and the feasibility of the measurement method was verified. The method shortens the distance between the mid-range and the baseline field to indoor completion.
2019 Vol. 40 (5): 776-779 [Abstract] ( 336 ) HTML (1 KB)  PDF (680 KB)  ( 287 )
780 The Research of Auto Electric Seat's Position and Orientation Adjustment Method Based on Machine Learning
LIU Bao-hua,YAO Yue-xuan,SUN Yu-kun
DOI: 10.3969/j.issn.1000-1158.2019.05.07
To solve the coupling phenomenon in the adjustment process of auto electric seat before delivery, a method of seat pose adjustment based on machine learning is proposed. According to the internal mechanical structure of the seat, the position between specific points on the seat surface is linearly dependent. The location information of these points is collected by laser range sensor, based on the information, the piecewise ridge regression model, which is derived from the further training of ridge regression model by linear classifier is established and the adjustment scheme is given. The feasibility of the proposed method is verified by experiments, and the experimental results show that, according to the prediction of the piecewise ridge regression model, each switch only needs to be moved once to make the seat posture meet the factory standard and the error of seat posture adjustment can be reduced, so the proposed method can significantly improve the efficiency of seat posture adjustment.
2019 Vol. 40 (5): 780-785 [Abstract] ( 329 ) HTML (1 KB)  PDF (1582 KB)  ( 272 )
786 Visual Field Measurement Method for protective eyeglasses based on Computer Vision
ZHAO Min,LIU Dan,LI Yi,QIAO Wei-dong
DOI: 10.3969/j.issn.1000-1158.2019.05.08
In view of the singularity and inefficiency of visual field measurement for protective eyeglasses at present, a visual field measurement method for protective eyeglasses based on computer vision is proposed, and an experimental measurement system is established. A standard head model and two fiber light sources are used to simulate the visual field when the eyes look straight ahead. By comparing the changes of the projection area before and after wearing eyeglasses, the qualification of the visual field of the eyeglasses can be determined quickly. The projection image of the measured eyeglasses is analyzed, then the outline information of the eyeglasses is clustered and extracted. The visual field is calculated according to the angle relationship between the pupil and the eyeglasses. The experimental results show that the method has the characteristics of high efficiency and intelligence compared with traditional methods. It only takes 10 second to determine qualification of the visual field of an eyeglasses. The error analysis of the measurement system is carried out and the final extended uncertainty is U=0.8(k=2). The system meet the practical demand of the visual field detection of protective eyeglasses.
2019 Vol. 40 (5): 786-792 [Abstract] ( 321 ) HTML (1 KB)  PDF (1081 KB)  ( 454 )
793 Fast and Accurate Recognition of Low-contrast Defects Workpiece Surface
SHAO Wei,PENG Peng,ZHOU A-wei,ZHAO Di
DOI: 10.3969/j.issn.1000-1158.2019.05.09
At the low contrast defects of the workpiece surface, a new method for grayscale statistical analysis and recognition based on image grid is proposed. First, construct the filtering method using the spatial and range information to process the original image; then carries on the grid division of the image, and the gray value of the image of grid entropy statistical analysis, to achieve recognition of defect targets. The experimental results show that the accuracy rate of low contrast defect recognition reaches 97.1%.
2019 Vol. 40 (5): 793-797 [Abstract] ( 290 ) HTML (1 KB)  PDF (646 KB)  ( 323 )
798 Smoke Detection Algorithm Combined with Improved Gaussian Mixture and YOLOv2
CHENG Shu-hong,MA Ji-yong,ZHANG Shi-jun1ZHANG Dian-fan
DOI: 10.3969/j.issn.1000-1158.2019.05.10
A smoke detection algorithm based on improved Gaussian mixture and YOLOv2 is proposed to detect fire timely and effectively. First of all, according to the characteristics of the early smoke makes the improvement to the Gaussian mixture, effectively framing the dynamic target region of interest, to extract the smoke foreground based on smoke detection; converted to regression problems, using end-to-end target detection algorithm YOLOv2 smoke training data set, second detection and screening, the final box set and the specific location the scope of the smoke area, meet the effective detection of the different scenes of smoke. The experimental results show that the fusion algorithm improves the detection effect of smoke area, improves the accuracy and effectively reduces the false detection rate to the smoke.
2019 Vol. 40 (5): 798-803 [Abstract] ( 360 ) HTML (1 KB)  PDF (1500 KB)  ( 626 )
804 Thermodynamic Temperature Measurement of the Indium Freezing Point with Johnson Noise Thermometry
ZHOU Zhen-yu,QU Ji-feng,ZHOU Kun-li,YAO Yan,CAI Jin-hui,ZENG Jiu-sun,XU Xun
DOI: 10.3969/j.issn.1000-1158.2019.05.11
Thermodynamic temperature researches show that there are certain differences between the fixed point defined in International Temperature Scale of 1990 and the real thermodynamic temperature. A heat source detection device for indium freezing point measurement is developed, and the electromagnetic interference is suppressed obviously in high temperature and complex environments based on the quantum voltage calibrated Johnson noise thermometry. Measurements over a bandwidth of 20～500kHz and a total integration time of 100h gives a measured value of Tin=429.7476K, with a relative standard uncertainty of 11.58×10-6, the relative offset from the ITS-90 is 0.9mK. The results provide a reference for the revision of the International Temperature Scale.
2019 Vol. 40 (5): 804-809 [Abstract] ( 306 ) HTML (1 KB)  PDF (1174 KB)  ( 471 )
810 Study on Non-steady Temperature Field Measurement ofInfrared Thermal Image under Different Emissivity
SHEN Jiu-li,ZHANG Yu-cun
DOI: 10.3969/j.issn.1000-1158.2019.05.12
By analyzing the formula of infrared temperature measurement, the influence of the object surface emissivity on the accuracy of infrared thermal image is studied. The factors affecting the emissivity of the object are found. According to the classical calculation method, the limitation of classical emissivity calculation method in infrared temperature measurement is explained. Based on the emissivity of the infrared image, a model of improving the temperature accuracy of the non-steady state temperature field is obtained, and a model is established, which is correction of emissivity of objects to improve the temperature measurement accuracy of infrared thermal image of non-steady temperature field. Three temperature measurement experiments of cast iron and stainless steel are carried out. The maximum errors of direct measurement of infrared thermal images are 2.1℃, 1.7℃ and 2.3℃ respectively, while the maximum errors of the proposed method are 1.0℃, 0.7℃ and 1.6℃ respectively.The correctness and feasibility of this method is verified by the experimental results.
2019 Vol. 40 (5): 810-815 [Abstract] ( 337 ) HTML (1 KB)  PDF (842 KB)  ( 762 )
816 Study on Measurement of Water Vapor Diffusion Coefficient of Building Materials by Spherical Absorption Method
WANG You-hui,TIAN Shuai-qi,MA Meng-chen,WANG Shi-yin,XU Xu, FAN Li-wu,YU Zi-tao
DOI: 10.3969/j.issn.1000-1158.2019.05.13
An experimental approach was built for measuring the diffusion coefficient of water vapor by a spherical absorption method, taking the typical porous building material aerated concrete as an example. Meanwhile, through uncertainty analysis and method verification, the feasibility and accuracy for measuring the water vapor diffusion coefficient of building materials were investigated. It is concluded that the spherical absorption method is suitable for measuring the water vapor diffusion coefficient of porous building materials and it has the advantages of short time and accurate results. For aerated concrete, the half-time method is more accurate than transient techniques in calculating water vapor diffusion coefficient. The water vapor diffusion coefficient of aerated concrete gradually increases between 45% and 80% relative humidity. While at higher humidity, water vapor diffusion coefficient gradually decreases due to the appearance of liquid water.
2019 Vol. 40 (5): 816-822 [Abstract] ( 308 ) HTML (1 KB)  PDF (974 KB)  ( 307 )
823 Study on Transfer Standard Stability of Flow Facilities Comparison Based on Principal Component Analysis
MENG Tao, WANG Chi, XING Chao
DOI: 10.3969/j.issn.1000-1158.2019.05.14
A transfer standard that were composed of an electromagnetic flowmeter and a turbine flowmeter connecting in serial was designed for water flow facilities comparison. The principal component analysis method was used to separate the dispersion of the comparison participating facilities and the fluctuation of transfer standard, and its principle and implementation process were presented. The applicability of the principal component analysis method was studied. According to the relationship between different principal components, a set of evaluation criteria for the transfer standard stability was proposed. Taking a water flow facilities comparison as an example, the validity of the comparison result was evaluated from the perspective of transfer standard stability, and the estimated value is 0.015%. The method improves the reliability of the evaluation standard for comparison, and can also be used to optimize the comparison route and shorten the comparison time.
2019 Vol. 40 (5): 823-828 [Abstract] ( 333 ) HTML (1 KB)  PDF (890 KB)  ( 236 )
829 Transient Electromagnetic Flow Measurement Method Based on Voltage-to-current Ratio and its Realization
WU Jian-ping,XU Ke-jun,XU Wei,WANG Chun-chang,YU Xin-long
DOI: 10.3969/j.issn.1000-1158.2019.05.15
In order to achieve higher excitation frequency, improve response speed, and reduce the power consumption of electromagnetic flowmeter, the transient measurement method based on voltage-to-current ratio was proposed to determine the relationship between voltage-to-current ratio and flow. The hardware based on DSP was designed, then the excitation current and signal voltage in the transient state was collected to verify the processing method. The analysis of off-line data indicated that the relationship between ratio and flow is well. The transient measurement method was implemented in real time by the designed DSP software, and the calibration experiment of water flow was performed, and the power consumption was also tested. The results of experiment show that the measurement accuracy reaches class 0.5, same as ordinary electromagnetic flowmeter. Comparison shows that excitation power consumption of electromagnetic based on transient measurement principle is 30% of the ordinary.
2019 Vol. 40 (5): 829-834 [Abstract] ( 310 ) HTML (1 KB)  PDF (423 KB)  ( 303 )
835 Soft Sensing Method for Water Cut of Crude Oil Based on Random Forest Algorithm
WANG Peng,GONG Pan,FENG Ding,TU Yi-liu
DOI: 10.3969/j.issn.1000-1158.2019.05.16
Real time measurement of wellbore output fluid is a key step in obtaining information from the downhole liquid production and an important prerequisite for the realization of intelligent well. However, there is no better way to measure the content of each component of the output liquid, because of the complexity of downhole environment and the uncertainty of oil-water mixture state. Aimed at the problem of mixed measurement of oil and water in the downhole, a soft sensing method for water cut of crude oil based on machine learning algorithm was presented. Combined with the needs of oil production engineering, water cut of crude oil was divided into 11 categories at 10% intervals. Taking physical properties corresponding to different water cut of crude oil as measurement object, the relationship between physical properties and water cut of crude oil was obtained and then the purpose of measuring the water cut of crude oil was realized, by learning and classifying known samples using random forest algorithm. Finally, the soft sensing method was verified by a designed indoor experiment. The results show that the predicted results by using the mentioned method agree with the experimental values , which can preliminarily meet the requirement of engineering for measuring water cut of underground crude oil and providing a new concept for downhole measurement.
2019 Vol. 40 (5): 835-841 [Abstract] ( 296 ) HTML (1 KB)  PDF (1124 KB)  ( 395 )
842 Gait recognition based on plantar pressure signal
HAN Ya-li,WU Zhen-yu,XU Yong-long,ZHANG Meng,SHEN Pei
DOI: 10.3969/j.issn.1000-1158.2019.05.17
A plantar force measurement system was designed based on the pressure sensor. Selecting the layout of the pressure sensor, designing the signal conditioning circuit to amplify and filter the collected pressure signal, the hardware platform was build and the signal acquisition interface was designed; The sensor calibration experiment and the foot force measurement system experiment were performed to collect the pressure signal when the object was walking at different speed at different statement; Taking the proportional calculation, determining fuzzy sets, designing membership functions, the fuzzy processing was carried out and the fuzzy rules was established by Larsen product Hint method, finally, the gait phase was inferred from the fuzzy output signal.
2019 Vol. 40 (5): 842-847 [Abstract] ( 342 ) HTML (1 KB)  PDF (802 KB)  ( 862 )
848 Signal Feature Extraction Method Based on Multi-scale High-order Singular Spectrum Entropy
ZHANG Shu-qing,CHEN Rong-fei,ZHANG Li-guo,YAO Jia-chen,MU Yong2LIU Yong,HUANG Yi-chen
DOI: 10.3969/j.issn.1000-1158.2019.05.18
A feature extraction method based on variational mode decomposition (VMD) for high-order singular spectral entropy is proposed and applied to fault diagnosis of rolling bearings. Firstly, the fourth-order cumulant slice is used to replace the covariance matrix of singular spectrum entropy analysis (SSEA), and the VMD decomposition method is introduced to multi-scale. The multi-resolution high-order singular spectrum entropy analysis of bearing vibration signal is proposed. Through signal analysis, VMD solves the problem of modal aliasing and can realize signal filtering. At the same time, the entropy feature vector extracted by the method enhances the robustness of phase space reconstruction parameters. By comparing with the wavelet singular spectrum extraction feature, the results show that the proposed method is more advantageous in overcoming the frequency aliasing phenomenon and the small overall dispersion of feature points. Finally, the classification of faults is realized by combining the deep belief network classifier. The validity and feasibility of the proposed method are verified by the results.
2019 Vol. 40 (5): 848-854 [Abstract] ( 293 ) HTML (1 KB)  PDF (2096 KB)  ( 454 )
855 Fault Diagnosis of Rolling Bearing Based on Sparse Representation of Signals and Transient Impulse Signal Multifeature Extraction
MENG Zong,YIN Na,LI Jing
DOI: 10.3969/j.issn.1000-1158.2019.05.19
A multi-feature extraction method based on IChirplet atom is proposed to solve the problem of sparse representation and feature extraction of transient impact signal. According to the characteristics of the fault signal, a dictionary which is made up of IChirplet atoms is built and a improved pariticle swarm optimization algorithm is presented for searching the best atoms. And then sensitive parameters in time-frequency domain of the IChirplet atomics and characteristics of the reconstructed signal are extracted as the characteristic parameter. Finally, the fault classification is achieved by PSO_SVM. The experiment proves that the IChirplet atom can match the fault signal of rolling bearing well, and the multiple characteristics can better reflect fault information and the bearing failure type can be judged more accurately.
2019 Vol. 40 (5): 855-860 [Abstract] ( 304 ) HTML (1 KB)  PDF (463 KB)  ( 374 )
861 Adaptive Decoupled Sliding Mode Control for Overhead Crane Mechanical System
ZHANG Zhi-ming,ZHENG Wei,XIE Ping,WANG Hong-bin,LI Ning,WEN Shu-huan,WANG Hong-rui
DOI: 10.3969/j.issn.1000-1158.2019.05.20
The dynamic model of the overhead crane mechanical system was constructed by employing the Lagrange equation theory, then the model was simplified and analyzed. First, the new saturation function was introduced for the coupling problem of the overhead crane mechanical system. Secondly, the decoupled sliding mode controller was designed based on the saturation function, the desired trajectory can be tracked precisely, and the position tracking error of the swing angle can converge to an adjustable bounded region. Then, by introducing the adaptive parameter, the chattering problem caused by the switching gain of the decoupled sliding mode controller can be solved. Finally, the simulations were performed to show the effectiveness of the proposed methods. From the simulations, it can be seen that the decoupled sliding mode controller with adaptive parameter has better control performance, and the dynamic characteristics of the mechanical system is improved.
2019 Vol. 40 (5): 861-867 [Abstract] ( 254 ) HTML (1 KB)  PDF (1339 KB)  ( 247 )
868 Research on Roller Characteristics of Two Degree of Freedom Rolling Mill Based on Vibration Absorber Control
LIU Bin,JIANG Jia-lei,PAN Gui-xiang,WANG Xiao-dong
DOI: 10.3969/j.issn.1000-1158.2019.05.21
Considering the nonlinear spring force constraint of the four-roll mill hydraulic cylinder, the vibration absorber control device was introduced. Then, a two-degree-of-freedom rolling mill roll model with a vibration absorber was established. By analyzing the equilibrium point of the rolling mill coupling system, it is concluded that increasing the stiffness coefficient of the vibration absorber can effectively avoid the Hopf bifurcation and chaotic dynamic behavior. By analyzing the spectrum curve and the time domain curve, it is concluded that the vibration absorber device can be increased the distance between the resonant frequency. The main resonance frequency, and shorten the time when the rolling mill roller system converges from the unstable state to the stable period. Through the amplitude-frequency characteristic curve, it is concluded that reducing the mass of the vibration absorber within a certain range can improve the stability of the system. Increasing the spring force of the vibration absorber, the unstable region of the system can be get smaller. Increasing the friction of the vibration absorber, the vibration amplitude of the system can be reduced.
2019 Vol. 40 (5): 868-874 [Abstract] ( 304 ) HTML (1 KB)  PDF (454 KB)  ( 346 )
875 Centrifugal Dynamic Force Calibration Device Based on Servo Drive
CAI Yong-hong,SUN Xiao-hui
DOI: 10.3969/j.issn.1000-1158.2019.05.22
To improve the calibration accuracy of force sensors used in quasi-static environment, a centrifugal dynamic force calibration device based on servo drive was developed. The device had a direct drive servo motor to drive and control the mass block for centrifugal motion, and outputted controllable dynamic force through bearingless transmission mechanism. The dynamic model was established and validated by experiments, and the measurement repeatability and dynamic response performance were experimentally studied. The experimental results showed that the repeatability of the calibration device was better than 1% at medium and high rotational speeds, and the calibration device could accelerate to the rated speed 500 r/min and output 3.8 kN force in 0.242 s.
2019 Vol. 40 (5): 875-879 [Abstract] ( 310 ) HTML (1 KB)  PDF (539 KB)  ( 346 )
880 Noise Reduction Effect Of Minimum Control Recursive Average Algorithm On Optical Fiber Acoustic Sensor System
GUO Mao-sen,WANG Yu,ZHANG Jian-guo,LIU Xin,BAI Qing,WANG Dong,JIN Bao-quan
DOI: 10.3969/j.issn.1000-1158.2019.05.23
In order to solve the problem of sound reduction in distributed optical sound sensing system in harsh environment, a multi-channel optical fiber acoustic sensing system based on improved minimum control recursive average (IMCRA) algorithm was established. The composite optical path structure of Sagnac and Mach-Zehnder was built, and the single-mode optical fiber was used as the sensing unit to pick up the sound signal. The multi-channel signal acquisition was realized by the optical switch, and the sound signal was denoised, restored and enhanced by the IMCRA algorithm. The experimental results show that the system can realize multi-channel scanning and picking of single-tone signals and voice signals on the sensing fiber with a length of 4km, and can effectively improve the signal-to-noise ratio of the voice signal under complicated conditions. A new way for the application of optical fiber acoustic sensing systems is provided in harsh environments.
2019 Vol. 40 (5): 880-886 [Abstract] ( 320 ) HTML (1 KB)  PDF (2206 KB)  ( 429 )
887 Ultrasonic Image Defect Classification Based on Support Vector Machine Optimized by Genetic Algorithm
ZHANG Mo,ZHENG Hui-feng,NI Hao,WANG Yue-bing,GUO Cheng-cheng
DOI: 10.3969/j.issn.1000-1158.2019.05.24
Ultrasound image defects are classified at a low accuracy due to problems such as small sample size, large sample categories, and difficulty in distinguishing. Aiming at these problems, an ultrasonic image defect classification method based on support vector machine optimized by genetic algorithm was proposed. First, the feature data of ultrasonic image defect is extracted by image processing. Then, the support vector machine was trained as ultrasonic image defect classifiers. Finally the parameters of the classifiers were optimized by genetic algorithm to obtain the optimal classifiers. The experimental results show that the proposed ultrasonic image defect classifier is superior to the other methods in the recognition rate, and the comprehensive recognition rate reaches 90%, which can effectively assist the staff to classify and identify the ultrasonic image defects.
2019 Vol. 40 (5): 887-892 [Abstract] ( 316 ) HTML (1 KB)  PDF (1386 KB)  ( 729 )
893 Study on Quantitative Evaluation Method of Ultrasonic C-scan Equipment
GENG Zhe,ZHU Hai-jiang,YANG Ping,HE Long-biao
DOI: 10.3969/j.issn.1000-1158.2019.05.25
The ultrasonic C-scan system has been widely applied in the ultrasonic imaging detection, defect recognition of nondestructive testing, however, the accurate analysis and characterization of the defects of ultrasonic C-scan images is always one of the difficult problems in the ultrasound.Based on the ultrasonic C-scan defect image, a quantitative estimation method of defect image feature parameters combining K-means clustering with Graham algorithm is presented.The quantitative estimation parameters can effectively evaluate the detection quality of the ultrasonic C-scan system.The experimental results show that the proposed method may effectively describe the characteristics of the standard circular artificial defect image, and the quantitative feature parameters may be used to evaluate further the ultrasonic C-scan equipment.
2019 Vol. 40 (5): 893-899 [Abstract] ( 283 ) HTML (1 KB)  PDF (1288 KB)  ( 795 )
900 Long-term Parameter Estimation of High Performance Rubidium Atomic Clocks
SHEN Ting-mei,YANG Tong-min,YAN Dong-liang
DOI: 10.3969/j.issn.1000-1158.2019.05.26
To focus on the main parameters predictions of high performance rubidium clocks widely used in time keeping systems, a three dimensional state vector estimation model of rubidium clock was presented. The parameters used in this clock estimation model were based on Hadamard variance by nonlinear curve fitting in least-squares sense. With daily data points observed successively for more than 2 months, the state vector estimations of Rubidium clock were obtained. Compared the estimations of the model with the least-squares model, it showed that the characteristic parameters estimation error is much smaller than least-squares linear model, the Model can give the frequency aging rate of rubidium clocks in real time.
2019 Vol. 40 (5): 900-903 [Abstract] ( 294 ) HTML (1 KB)  PDF (699 KB)  ( 338 )
904 Study of High Precision Time Synchronization System Based on NIMDO and Optical Fiber Transfer
LONG Bo,WANG Ju-feng,HUANG-XU Rui-han,ZHANG Yu,HAN Feng,SHEN Li
DOI: 10.3969/j.issn.1000-1158.2019.05.27
A high precision time synchronization system was studied and designed which aimed at synchronizing time in public security traffic management department. The system based on NIMDO traced and synchronized time standard to UTC(NIM) in near real time by satellite common-view method. It transferred time standard hierarchically to public security traffic management department, which combined with optical fiber transfer technology, precise time protocol and network time protocol. The results of validation and analysis showed that 90.53% of the time offset between NIMDO and UTC (NIM) maintained within ±5ns and 98.60% maintained within±20ns; the time offset between the clock units and the time standard were -4.45~4.85 ns when the single-fiber bidirectional transfer was used, 5.01~24.99μs when double-fiber bidirectional transfer was used, 0.64~4.60ms when network time protocol was used. The results showed that the system solved the problem of time traceability and synchronization, and can provide reference for time synchronization in other fields.
2019 Vol. 40 (5): 904-909 [Abstract] ( 280 ) HTML (1 KB)  PDF (1884 KB)  ( 419 )
910 Research on Time Delay Measurement Technology for Satellite Navigation Receivers
ZHU Jiang,LI Zhen-hua
DOI: 10.3969/j.issn.1000-1158.2019.05.28
The use of satellite navigation receivers for high-precision time synchronization is a simple and effective timing synchronization means. The accurate time delay measurement of navigation receiver is the precondition of high precision timing, and the delay of output second pulse signal is the key to the long-distance timing synchronization. Based on the determination of the delay of the satellite navigation receiving system, by analyzing the delayed composition and characteristics of the satellite navigation receiver, the delay composition model of the satellite navigation receiver is established, the method of delay determination of the satellite navigation receiver is developed, and a complete delay determination system of the satellite navigation receiver is set up. The calibration and experimental verification of the system are also carried out
2019 Vol. 40 (5): 910-913 [Abstract] ( 300 ) HTML (1 KB)  PDF (807 KB)  ( 496 )
914 A Comparison of Activity Analysis of γ Radionuclides in Water
YANG Zhi-jie,LIU Hao-ran,LIANG Jun-cheng,ZHU Da-bin,WANG Nan-ping
DOI: 10.3969/j.issn.1000-1158.2019.05.29
In order to examine the accuracy and consistency of measurement results in measurement laboratories, measurement comparison had been organized to measure the same sample with the same properties between multiple laboratories. After the comparison, a full-factor check for levels of the measuring instruments, measuring personnel, operating procedures and daily quality control of each participating laboratory had been achieved. From 2017 to 2018, the comparison of radioactivty analysis of the gamma radionuclides in the water of China General Nuclear Power Group was organized and implemented. 15 laboratories from 6 major nuclear power bases participated in the comparison, and submitted 23 comparison results. The data were analyzed according to the relative deviation comparison method, En evaluation method and the Z-scores method. Finally, in order to compare the advantages and disadvantages of the comparison results, combined with the special situation in the field of nuclear power, the eligibility of the comparison results had been distinguished based on the En evaluation and Z-scores comprehensive evaluation method. Based on the evaluation criteria, the pass rate of the nuclide 57Co, 137Cs and 241Am is 95.7%; the pass rate of the nuclide 109Cd and 60Co is 91.3%.
2019 Vol. 40 (5): 914-919 [Abstract] ( 277 ) HTML (1 KB)  PDF (775 KB)  ( 444 )
920 Monte Carlo Simulation Method for g Factor
LI De-hong,HUANG Jian-wei,Shabiha Tuerxun,WU Qi
DOI: 10.3969/j.issn.1000-1158.2019.05.30
In the process of establishing the primary standards of air kerma, the g factor is one of the key components,which is involved in the value recurrence and uncertainty calculation, and the calculation of g factor required the mass energy transfer coefficient and mass energy absorption of the photon. The results were got and compared by using different software to simulate with different parameter settings. The results show that the calculation results from EGSnrc are more reasonable, especially for low-energy photons, although the g factor is relatively small. The values obtained under different parameter setting conditions are quite different. Therefore, attention should be paid to the physical mechanism of the relevant interactions in the process of the calculation and the use of the mass-energy transmission coefficient and the mass-energy absorption coefficient for low-energy photons.
2019 Vol. 40 (5): 920-923 [Abstract] ( 316 ) HTML (1 KB)  PDF (320 KB)  ( 575 )
924 Uncertainty Research of the Seawater Salinity Measurement Standard Based on Weight Dilution Method
WANG Peng-peng,ZHAO Shi-wei,YANG Jian,CHENG Jie,QI Jiu-cheng,LIU Yuan-yuan,WU Xin-zhu
DOI: 10.3969/j.issn.1000-1158.2019.05.31
The comprehensive and detailed uncertainty analysis of the seawater salinity measurement standard based on weight dilution method was studied, especially the transfer relation between the quality and salinity, and the detailed analysis of the components introduced in the process, which provided a detailed technical reference for the improvement of the source traceability and transmission system of the salinity standard value. The results showed that the standard seawater samples prepared by the “weight dilution method” were within the range of 2~35 salinity, and its maximum expansion uncertainty was equivalent to the standard seawater of the first grade in China. The standard seawater samples were tested with the 8400B laboratory salinometer, and the results were fully satisfied with the salt standard equipment.
2019 Vol. 40 (5): 924-928 [Abstract] ( 354 ) HTML (1 KB)  PDF (354 KB)  ( 445 )
929 Prediction of Boiler NOx Emission Based on Mixed Chicken Swarm Algorithm and Kernel Extreme Learning Machine
NIU Pei-feng,DING Xiang,LIU Nan,CHANG Ling-fang,ZHANG Xian-chen
DOI: 10.3969/j.issn.1000-1158.2019.05.32
Taking a 300 MW subcritical circulating fluidized bed boiler as an object of study, the NOx emission of the boiler was predicted accurately. A model about NOx emission from different working conditions was established using hybrid chicken swarm optimization based on simulated annealing(SACSO) and kernel extreme learning machine(KELM). By comparing in the differential evolution algorithm(DE), the particle swarm optimization(PSO) and the original chicken swarm optimization(CSO), the superiority of the improved algorithm was proved. Then, several models were compared in traditional BP algorithm, support vector machine (SVM), extreme learning machine (ELM) and KELM.The Finally determinded SACOS-KELM model has higher prediction accuracy, stability and better generalization ability, so this model is a good choice for boiler NOx emission in modeling and prediction.
2019 Vol. 40 (5): 929-936 [Abstract] ( 286 ) HTML (1 KB)  PDF (1495 KB)  ( 358 )
937 Uncertainty Evaluation for the Determination of the Acid Number of Lubricant Oils by Potentiometric Titration
QIU Hui-rao,PANG Jin-shan
DOI: 10.3969/j.issn.1000-1158.2019.05.33
Acid number in lubricating oil was measured by potentiometric titration. Establishing evaluation mathematical model of uncertainty of acid number test results to analyze the sources of uncertainty, the test results were evaluated. The acid number of the Mobil gear oil by potentiometric titration is 0.706 mg/g through repeated experiment. Type A and type B uncertainties of the result were evaluated,it showed that expanded uncertainty is 0.010 mg/g when coverage factor is k=2 and level of confidence is 95%.
2019 Vol. 40 (5): 937-940 [Abstract] ( 470 ) HTML (1 KB)  PDF (431 KB)  ( 262 )
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