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2020 Vol. 41, No. 9
Published: 2020-09-28
 
1033 Raman Scattering Enhancement Characteristic of Concave Tip
BO Tao,HU Jia-cheng,CAI Jin-hui,LI Dong-sheng,GAO Si-tian
DOI: 10.3969/j.issn.1000-1158.2020.09.01
The FDTD Solutions software which is based on the finite-difference time-domain method was used to establish a simulation model of the Ag-coated concave W tip and glass substrate. In the same conditions, within the Au-coated concave W tip-glass substrates, inner concave W tip-glass substrate models of near-field electric field numerical calculation, the design verified the effectiveness of the model in terms of enhanced Raman scattering. The results show that the structure can produce the largest Raman enhancement factor of the order of 105 in the case of an Ag-coated recessed W tip-glass substrate. The tip preparation device of the National Institute of Metrology of China was used to prepare the actual tip with optimized parameters, and the TERS measurement device in the laboratory was used to measure the TERS signal of SWCNTs, experiment rusults verify the effectiveness of the designed tip in Raman signal measurement.
2020 Vol. 41 (9): 1033-1038 [Abstract] ( 318 ) HTML (1 KB)  PDF (1645 KB)  ( 425 )
1039 A New Localization Method for Marine Wireless Sensor Networks Based on Asymmetric Round-trip Ranging
QIN Yu-hua,LIU Hao-ran,DENG Yu-jing,WANG Xing-qi,LIU Bin,YIN Rong-rong
DOI: 10.3969/j.issn.1000-1158.2020.09.02
A new localization method for marine wireless sensors networks based on asymmetric round-trip ranging(LMARR) is proposed. The algorithm uses the time difference between the asymmetric reception and transmission of ranging information between nodes to calculate the seawater sound velocity and the unknown between nodes. The distance between a node and its neighbors reference node, converts the three-dimensional distance information into two-dimensional, and uses the least square method to complete the localization calculation. Compared with the SWN and ARTL algorithms, simulation results show that the LMARR algorithm can effectively improve the accuracy of node localization, especially in the areas where the sound velocity of seawater continuously changes at a depth of 20～120m, the localization accuracy is 20% higher than the SWN algorithm, and is 33% better than ARTL. In addition, the LMARR algorithm also has high stability.
2020 Vol. 41 (9): 1039-1047 [Abstract] ( 314 ) HTML (1 KB)  PDF (2598 KB)  ( 321 )
1048 Calibration of Industrial Robot Parameters Based on Standard Ball Dis-tance Constraints
LU Yi,GE Wen-qi,GUO Bin
DOI: 10.3969/j.issn.1000-1158.2020.09.03
Aiming at the problem that the absolute positioning accuracy of current industrial robots is low and limited in industrial applications, based on standard ball distance constraint, a new method for industrial robot parameter calibration was proposed. Firstly, the MDH model was used to establish the robot kinematics model. Secondly, the contact probe was mounted on the end flange of the industrial robot, and a triangular calibration platform was built. The platform was rigidly connected with three standard balls with a diameter of 25.4mm. The theoretical center of the ball between each two balls was 300mm. The probe was used to separately detect the points on the three standard spheres, and record the values of the corresponding joint angles. Finally, the spherical center coordinates of the standard sphere were obtained by least squares fitting, and the distance was constrained from the actual spherical center distance measured by the coordinate measuring machine, and the kinematic parameter error was obtained by using the Levenberg_Marquardt algorithm. A total of 5 platform orientation experiments were performed and error compensation verification was performed using data from 5 other platform directions. The experimental results show that the average spherical center distance deviation decreases from 2.6812mm to 0.5694mm, and the standard deviation decreases from 0.6738mm to 0.1407mm.
2020 Vol. 41 (9): 1048-1054 [Abstract] ( 435 ) HTML (1 KB)  PDF (689 KB)  ( 1061 )
1055 Influence of Tracking Mode on Measurement Accuracy in Multi-Purpose Pose Measurement System
ZHANG Shuai,MIAO Dong-jing,LI Jian-shuang,ZHENG Ji-hui, WANG Guo-lei, KONG Ming,KAN Ying-nan
DOI: 10.3969/j.issn.1000-1158.2020.09.04
To accurately measure large size poses, a large size pose measurement device consisting of 7 laser tracking interferometers is established. According to the difference in the number of laser tracking interferometers measuring each mirror, the effects of two tracking methods, 322 and 331, on the accuracy of pose measurement are simulated. Therefore, it is found that the position of the measured point is related to the distance of the base station plane. The error model between the relative position between the measured point coordinate value and the measurement base station and the measurement error is derived from the coordinate solution formula. By analyzing the sensitivity of errors in the directions of x, y, and z to distance changes, it is found that errors caused by distance changes in the z direction are the most sensitive. When the distance between the measured point and the measurement base station is reduced from 1300.8mm to 0mm, the measurement error increases from 2.2μm to 2626.1μm. The actual attitude measurement experiment results show when a tracking method is adopted, the measured point can be avoided from being too close to the plane of the station, which is helpful to improve the measurement accuracy of the system.
2020 Vol. 41 (9): 1055-1061 [Abstract] ( 299 ) HTML (1 KB)  PDF (2226 KB)  ( 450 )
1062 Continuous Motion Thread Size Detection with Adaptive Machine Vision
BAO Neng-sheng,FANG Hai-tao
DOI: 10.3969/j.issn.1000-1158.2020.09.05
Because of the problem of low efficiency, high working intensity and low detection accuracy of threaded parts, the adaptive machine vision detection method of continuous motion thread size is proposed.Firstly, an online image acquisition device is designed to collect moving thread parts images.Secondly, NCC (normalized cross correlation) normalization matching algorithm is used to identify and track the threaded parts.On this basis, an adaptive ROI (region of interest) clipping region is designed; then the edge contour is extracted by Canny algorithm.The least squares straight line fitting technique is used to fit the thread profile straight line, the thread diameter line is generated, and the measurement of the thread diameter is completed.Finally, based on the Harris corner detection algorithm is used for multi-thread contour peak and trough extraction, it is proposed to use the distance between the thread diameter line and each corner point to complete the refinement of the diagonal point.Experiments show that the proposed method is feasible and effective in thread size detection.
2020 Vol. 41 (9): 1062-1069 [Abstract] ( 299 ) HTML (1 KB)  PDF (893 KB)  ( 803 )
1070 Research on Parameter Optimization of LED Based on Surface Plasmons
LI Zhi-quan,WEI Wen-jing
DOI: 10.3969/j.issn.1000-1158.2020.09.06
In order to effectively improve the luminous efficiency of GaN-based blue light-emitting diodes, a composite grating GaN-LED structure based on surface plasmon is proposed. Through the theoretical analysis of the excitation mode of surface plasmons and the quantum efficiency of the internal and external LEDs, the principle of the structure to enhance the luminous efficiency of LEDs is explained in detail. The fabrication process of the model is discussed. At the same time, the finite element analysis method is used to optimize the parameters and simulate the structure, thus the radiation power, absorption power and electric field distribution of the structure under the optimal parameters are obtained. The simulation results show that when the wavelength of the emitted light is 460nm, under the optimal parameters, the average electric field radiated into the air of the composite grating LED structure is 38 times that of the single-grating LED structure, which proves that the proposed structure can effectively improve the luminous efficiency of the diode.
2020 Vol. 41 (9): 1070-1076 [Abstract] ( 297 ) HTML (1 KB)  PDF (1090 KB)  ( 296 )
1077 3D Visualization Method for Complex Lattice Structure Defects in 3D Printing
WEN Yin-tang,GAO Ting-ting,ZHANG Yu-yan
DOI: 10.3969/j.issn.1000-1158.2020.09.07
Due to the complex lattice structure of 3D printing is prone to defects such as cracks, unfused or holes, and its seriously affect the functional performance of structural parts, a 3D visual inspection method for 3D printed defects in a complex lattice structure was studied. Based on gray value difference feature of internal defect in CT images of lattice structure, a class of defects were automatic identified and segmented by using the collective gray value method, and the segmented defect image sequence was 3D reconstructed by using ray-casting method. The experiment results showed that the method proposed can effectively obtained a three-dimensional view of a typical defect inside the lattice structure, and from which the shape and size of defect can be described. A strong basis for further analysis of the impact of defects on structural performance is provided.
2020 Vol. 41 (9): 1077-1081 [Abstract] ( 342 ) HTML (1 KB)  PDF (1015 KB)  ( 604 )
1082 Geometric Parameter Measurement of Ultrasonic Flowmeter Based on Laser Tracker
CUI Hang,HU He-ming,LI Li-xia,GUO Chen-xi,XIE Dai-liang,YANG Zhuo,CHENG Zhen
DOI: 10.3969/j.issn.1000-1158.2020.09.08
For large diameter ultrasonic flowmeters with probes installed on existing pipe, geometric parameters measurement contribute a lot to the flowmeter accuracy, based on laser tracker, a geometrical parameter measurement method for large-diameter ultrasonic flowmeter is established. 3-D coordinates of pipe surface points and probe cylinder points are collected by laser tracker outside the pipe. Spatial model of the pipe and probes are built by a commercial tool, and then all the geometric parameters are calculated. Two field measurements of pump station pipes are performed to estimate the flow uncertainty due to different geometric parameters using this method. The method not only solves the problem of geometric measurement outside the pipe, and the uncertainty level is also controlled at around 0.2%. Compared with the measured values by the laser tracker, it is show that there are not small deviation in the setting values by manufacturers, which needs to be paid more attention by manufacturers and owners.
2020 Vol. 41 (9): 1082-1088 [Abstract] ( 301 ) HTML (1 KB)  PDF (1074 KB)  ( 234 )
1089 Comparative Study on the Influence of Curvature Radius of Needle Tip on Scratch Test of Hard Film Bonding Force
YU Jie,TAO Xing-fu,QIN Lin,LI Xiao-bing
DOI: 10.3969/j.issn.1000-1158.2020.09.09
The film/base bonding force is an important characteristic parameter of the hard film materials. In the adhesion test of the hard film by the scratch method, there are many factors that affect the determination of the critical load Lc, such as the hardness & modulus of the film and the substrate, the surface roughness of the film, and so on. In addition, the test parameters including the instrument stiffness, the scratch rate, the radius of curvature of the indenter, etc., also affect the determination of the critical load Lc. The effects of three indenters with different radius of curvature (20μm, 50μm and 100μm) on the adhesion test of diamond-like carbon films with thickness of submicron were studied. Two differents substrate (i.e. single crystal silicon and 304 steel) were considered. The critical load of the two materials increases, as the increase of the radius of curvature of the tip.
2020 Vol. 41 (9): 1089-1094 [Abstract] ( 278 ) HTML (1 KB)  PDF (849 KB)  ( 251 )
1095 Effects of Normal Load on Microscratch Test of Copper
LIU Ming,YAN Fu-wen,GAO Cheng-hui
DOI: 10.3969/j.issn.1000-1158.2020.09.10
Microscratch experiment was carried out on copper with the Rockwell C diamond conical indenter to investigate the effect of normal load on microscratch test of the sample. Results show that as normal load increases, both penetration depth and residual depth increase linearly, and elastic recovery rate decreases linearly; scratch width increases nonlinearly during the initial stage and then rises linearly with the increasing penetration depth. When normal load varies from 0.08 N to 0.11 N, the friction force increases linearly, the friction coefficient tends to keep constant, and the friction mechanism is adhesion friction; when normal load varies from 0.11 N to 17 N, both the friction force and the friction coefficient nonlinearly increase, and the friction mechanism is ploughing friction; when normal load varies from 17 N to 28 N, the friction coefficient tends to keep constant, the friction force increases linearly, and the friction mechanism is micro-cutting.
2020 Vol. 41 (9): 1095-1101 [Abstract] ( 265 ) HTML (1 KB)  PDF (1005 KB)  ( 627 )
1102 Acoustic Characteristics Analysis of Multilayer Media Based on Magnetic Resonance Imaging
ZHU Qin-feng,ZHENG Hui-feng,WANG Yue-bing,CAO Yong-gang
DOI: 10.3969/j.issn.1000-1158.2020.09.11
Based on magnetic resonance images, a method for analyzing the acoustic characteristics of multilayer media was proposed, and the focal point of ultrasound passing through the layered structure was estimated.Firstly, after performing edge extraction such as region extraction, threshold segmentation, corrosion expansion on the magnetic resonance T1-weighted image of the sucrose solution, the average gray value of the local region was obtained.Then, the relationship function was calculated by calculating the relationship between the grayscale information on the magnetic resonance image and the concentration and sound velocity of the corresponding sucrose solution.Finally, a layered structure of sucrose solution that simulates biological tissues was established, and the relationship function was used to calculate the acoustic transmission of ultrasound through the layered structure and the focus forward movement of focused ultrasound.The experimental results show that the method analyzes the sound velocity, acoustic transmission coefficient and focus advance from the sucrose solution magnetic resonance image, compared with the actual value obtained by the experiment, the maximum difference is 0.6239mm, it is verified the possibility of acquiring biological tissue acoustic parameters can through magnetic resonance.
2020 Vol. 41 (9): 1102-1108 [Abstract] ( 326 ) HTML (1 KB)  PDF (1839 KB)  ( 580 )
1109 Sound Field Simulation and Calibration Experiment based on Circular Array
GAO Lan,WANG Yue-bing,JIA Meng-wen
DOI: 10.3969/j.issn.1000-1158.2020.09.12
In view of the problem of acoustic multipath effect in circular array, a method of using the ring array with unequal spacing to destroy the coherence of each path is proposed to reduce the sidelobe performance and the interference of edge diffraction reflection. The simulation results show that the unequal spacing ring array can effectively reduce the side lobe of focused beam, and the optimal ring array structure is designed according to the simulation results. Finally, the acoustic field calibration experiment of the ring array is carried out in the experimental pool, the transducer array is excited by the pulse wave and the continuous wave at the frequency of 4~8kHz respectively. The results show that the axial sound pressure characteristics of the transducer can be accurately measured in the limited space by the method of pulse sinusoidal signal excitation.
2020 Vol. 41 (9): 1109-1114 [Abstract] ( 357 ) HTML (1 KB)  PDF (1805 KB)  ( 446 )
1115 The Precise Measurement Method for Settling Time of Hopping Sine Wave Based on Four-parameter Sinusoidal Curve-fit
LIANG Zhi-guo,HE Zhao,LIU Yuan,ZHANG Yi-chi,WU Ya-hui
DOI: 10.3969/j.issn.1000-1158.2020.09.13
Aiming at the problems in accurate measurement of settling time of sinusoidal generator in state changing, switch on, and overloading recovery, a method based on local area four-parameter sine wave curve-fitting is presented. Then, the four fitting parameters are used to the whole area of sampling wave, and the residual error wave between the fitting curve and the sampling wave is gotten. It takes the convergence courses of residual error in settling of sinusoidal. By using this residual error curve, and the condition criterion of the settling time of ourselves, both the beginning time point and the stopping time point are got, finally, the settling time of sinusoidal is calculated. In experiments of two different conditions, both the validity and the feasibility of the measurement method are proved. The method can also be used in settling time measurement of all of the pulse frequency modulation, pulse amplitude modulation, pulse phase modulation, and other digital modulation signal generators.
2020 Vol. 41 (9): 1115-1121 [Abstract] ( 268 ) HTML (1 KB)  PDF (726 KB)  ( 368 )
1122 Bayesian Network Structure Learning Based on Improved Hybrid Genetic Bacterial Foraging Algorithm
LIU Hao-ran,CHANG Jin-feng,PANG Na-na,LI Chen-ran,LU Ze-dan
DOI: 10.3969/j.issn.1000-1158.2020.09.14
Aiming at the problem that learning Bayesian network by heuristic learning algorithm is easy to get into local optimization and low searching efficiency, a hybrid improved genetic bacteria foraging optimization algorithm for learning Bayesian network structure was proposed. Firstly, the optimal population was obtained by genetic algorithm and used as the initial population of bacteria foraging algorithm. Then, in order to increase population diversity and expand search space, crossover and mutation strategies were used to improve the replication behavior of bacteria foraging algorithm. Finally, the population was updated through the initialization operation of the migration behavior of the improved bacteria foraging algorithm to prevent the loss of elite individuals. Through the iterative search of the population, the optimal Bayesian network structure was finally obtained.The simulation results show that the convergence accuracy and efficiency of this algorithm are improved compared with other algorithms.
2020 Vol. 41 (9): 1122-1126 [Abstract] ( 283 ) HTML (1 KB)  PDF (754 KB)  ( 561 )
1127 Research on ECT Image Reconstruction Algorithm Based on lp-norm
MA Min,SUN Mei-juan,LI Ming
DOI: 10.3969/j.issn.1000-1158.2020.09.15
In the process of ECT image reconstruction, non-convex compressed sensing algorithm based on lp-norm often has the problem of large computational complexity, and the algorithms corresponding to the proximal mapping of the regularization lp-norm minimization are limited to few specific values of parameter p, which leads to low image resolution. The improved interpolation function is used to replace xpp, by adjusting the parameters, the improved function is infinitely approximated to xpp. At the same time, the threshold representation theory is introduced, and based on it. A new adaptive threshold iterative algorithm is proposed to solve the new model. The experimental results show that the improved algorithm has stronger adaptability, higher image resolution and faster imaging speed than the Lanweber algorithm and iterative reweighted least squares method.
2020 Vol. 41 (9): 1127-1132 [Abstract] ( 291 ) HTML (1 KB)  PDF (929 KB)  ( 693 )
1133 Uncertainty Evaluation of Calibration Factor for X-ray Dose Equivalent Instrument
Lü Ya-zhu,ZHAO Rui,LI De-hong,Shabiha·Tuerxun,GUO Bin
DOI: 10.3969/j.issn.1000-1158.2020.09.16
In order to accurately evaluate the uncertainty of calibration factors of protective instruments for X-ray dose monitoring, according to the relevant technical specifications, the reference value of dose equivalent rate at the reference point is measured by standard ionization chamber, and the display value of the instrument to be calibrated is obtained by using the substitute method, so as to determine the relevant influencing factors of the calibration factor results, and evaluate the uncertainty of the influencing factors respectively.The relative expanded uncertainty of instrument calibration factor is 5.0% (k=2). The main sources of influence on the uncertainty of calibration factors include the uniformity of radiation field for calibration, calibration factors and energy response of the standard ionization chamber itself, dose equivalent conversion factor, statistical standard deviation of display value of instruments to be tested, etc. In the process of calibration, the uncertainty of calibration factor can be improved by increasing the uncertainty level of standard reference value.
2020 Vol. 41 (9): 1133-1137 [Abstract] ( 398 ) HTML (1 KB)  PDF (443 KB)  ( 618 )
1138 Improved Fast Tracking Echo State Network and PM2.5 Prediction
LIU Bin,LI De-jian,ZHAO Zhi-biao,WU You
DOI: 10.3969/j.issn.1000-1158.2020.09.17
Aiming at the problem that the recursive least squares echo state network has low prediction accuracy in noisy environments, an improved fast tracking echo state network was proposed. Firstly, the variable forgetting factor which can be adaptively adjusted was added into the cost function of network, and the output weights of the network were trained by the improved recursive least squares method to obtain a fast tracking echo state network. Then, the effectiveness of the proposed network was verified by classical Lorenz chaotic system. Finally, the grey correlation method was used to analyze the correlation between the relevant variables and PM2.5, and the auxiliary variable set of PM2.5 concentration value was established. The auxiliary variable set was input into the fast tracking echo state network to predict the PM2.5 concentration value. Experimental results show that compared with the traditional echo state network and the recursive least squares echo state network, the improved state echo network has better prediction accuracy and stronger anti-noise ability.
2020 Vol. 41 (9): 1138-1145 [Abstract] ( 301 ) HTML (1 KB)  PDF (1983 KB)  ( 585 )
1146 Optimization Research of Boiler NOx Emission Model Based on Improved Salp Swarm Algorithm
NIU Pei-feng,MIAO Kong-hao,SHANG Shi-xin,CHANG Ling-fang,ZHANG Xian-chen
DOI: 10.3969/j.issn.1000-1158.2020.09.18
In order to establish an efficient prediction model for NOx emission concentration, a 330 MW pulverized coal boiler was used as the research object and the adaptive salp swarm algorithm (ASSA) was used to optimize the fast learning network (FLN) to set up a prediction model. Firstly, the performance of ASSA was detected by 8 benchmark functions and compared with the other three algorithms. The results show that the convergence speed of ASSA algorithm is faster and the optimization result is better. In addition, the model was compared with the fast learning network, which was optimized by the differential evolution algorithm, the particle swarm optimization algorithm and the salp swarm algorithm. The results show that the ASSA-FLN model has better prediction accuracy and generalization ability, and can effectively and accurately predict the NOx emission of pulverized coal fired boilers.
2020 Vol. 41 (9): 1146-1151 [Abstract] ( 267 ) HTML (1 KB)  PDF (1100 KB)  ( 223 )
1152 Soft Measurement Method for Cement Clinker fCaO Based on Time Series Single-dimensional Convolutional Neural Network
ZHAO Yan-tao,HE Yong-qiang,JIA Li-ying,YANG Li-ming,HAO Xiao-chen
DOI: 10.3969/j.issn.1000-1158.2020.09.19
The content of free calcium oxide (fCaO) in cement clinker has an important impact on cement quality and production energy consumption.At this stage, the fCaO content of cement clinker is measured offline by chemical analysis method, but this method has obvious hysteresis for the operation guidance of the production process.Aiming at the problem that clinker fCaO could not be monitored online, a soft measurement modeling method of clinker fCaO based on multi-variable time series single-dimensional convolutional neural network (TS-CNN) was proposed.The time series of a certain historical time period that affects multiple variables of clinker fCaO was used as the models input, and the cement data was combined to extract the characteristics of each variable by using single-dimensional convolution pooling method to reduce the complexity of the network, and finally the extracted local information was integrated by the fully connected layer.Through the experimental comparison, the results show that the soft measurement method based on TS-CNN has higher prediction accuracy and more generalization ability.
2020 Vol. 41 (9): 1152-1162 [Abstract] ( 365 ) HTML (1 KB)  PDF (3425 KB)  ( 684 )
1163 Development of Acid Orange Ⅱ Purity Reference Material
ZHOU Jin-yan,HUANG Yan-jie,XU Jun-bin,HUANG Zi-chen,CHEN Ling,LIN Keng,HUA Xiu-bing,WANG Shi-chao
DOI: 10.3969/j.issn.1000-1158.2020.09.20
The mass balance method is a classic method to determine the purity of organic reference materials. The GBW(E)100373 Acid Orange II purity reference material was developed by the mass balance method, and the strict procedures of preparation, homogeneity test, stability test, value assessment, uncertainty evaluation, comparison and verification of reference materials were introduced. Finally, a purity reference material of acid orange II with certified purity value of 99.2% and relative expanded uncertainty of 1.0% (k=2) was obtained, which can play an important role in the fields of instrument calibration and method evaluation in food and cosmetic analysis.
2020 Vol. 41 (9): 1163-1170 [Abstract] ( 329 ) HTML (1 KB)  PDF (809 KB)  ( 599 )
1171 Study on Measurement Method of Bacillus subtilis var.niger Spore
DOI: 10.3969/j.issn.1000-1158.2020.09.21
Bacillus subtilis var.niger is an important indicator microbiology of biological protection and sterilization effect evaluation, and its accurate value can ensure the effectiveness and comparability of the evaluation. Spread plate method for bacillus subtilis was method validated, collaborative experimental verified, and uncertainty analyzed. The results showed that spread plate method has a good reproducibility and repeatability, within-laboratory relative standard deviation of repeatability is 10.0%, and inter-laboratory relative standard deviations is 14.1%, when the number of colonies on the plate is between 30CFU and 300CFU. The statistic test showed that the relative expanded uncertainty of spread plate method is 12.0% (k=2). This method can be used for quantitative measurement of bacillus subtilis var. niger spore, which has important significance for the evaluation of protective performance of personnel protective equipment, detection of disinfectants and quality control of sterilization.
2020 Vol. 41 (9): 1171-1176 [Abstract] ( 330 ) HTML (1 KB)  PDF (403 KB)  ( 386 )
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