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2023 Vol. 44, No. 6 Published: 2023-06-28

	837	Method for Rapid Verticality Detection of Aviation Drilling Holes
		YU Hou-yun,CHENG Ya-ni,SUN Yi-hong,FU Pan,QU Zheng-hang
		DOI: 10.3969/j.issn.1000-1158.2023.06.01
		To solve the problem of verticality detection of aviation drilling holes on site, a fast and high-precision method is proposed based on laser ranging sensor. Firstly, an expansion mandrel is stably supported in the hole to simulate its axis. Then the point cloud data of the holes end face is obtained with the ranging sensor and an angle encoder, which are both installed on the mandrel. And the normal vector of the face is further fitted. Finally, the angle between the vector and the axis is calculated as the verticality. At the same time, a 3D point cloud reconstruction algorithm based on RANSAC is proposed to improve the measurement accuracy. The systematic error, caused by the reference reflected by the expansion mandrel, is compensated after the vectors are synthesized. The measuring device is calibrated by verticality gauges and the experiments of verticality detection are completed for both plane and curved parts. The result shows that the measurement repeatability is less than 0.01° and the maximum indication error is within ±0.1°. It takes less than one minute for each hole. So the requirements of the accuracy and efficiency for on-site detection can be met.
		2023 Vol. 44 (6): 837-843 [Abstract] ( 224 ) HTML (1 KB) PDF (695 KB) ( 279 )

	844	Comprehensive Measurement of Cycloid Gear Accuracy Based on Machine Vision
		YIN Wan-wan,ZHAO Wen-hui,ZHANG Jing
		DOI: 10.3969/j.issn.1000-1158.2023.06.02
		In order to solve the problems of less information acquisition and slow measurement speed in cycloid gear detection, a comprehensive measurement method based on machine vision is proposed. According to the measurement accuracy requirements of cycloid gear, the visual detection hardware system is built. Fitting Facet gray surface along edge tangential window, the sub-pixel coordinate points are determined by using edge continuous surface features, and the positioning accuracy is 0.2pixel by measuring block detection. By pixel equivalent calibration, light intensity compensation and coordinate transformation, the sub-pixel tooth profile of cycloid gear is obtained in physical coordinate system. Compared with the cycloid profile measured by CMM, the difference of cycloid profile obtained is 10μm. According to the tooth profile equation of cycloid gear, the error calculation model of cycloid gear is established by combining rectangular coordinates and polar coordinates, and the tooth profile deviation and tooth pitch deviation are calculated. At the same time, the diameter of the center hole and the two crankshaft holes of cycloid gear are evaluated, and the relationship between tooth profile deviation and polar angle is obtained, which provides the basis for improving the processing technology of cycloid gear and analyzing the transmission performance of RV reducer. The whole measurement process takes about 16s.
		2023 Vol. 44 (6): 844-851 [Abstract] ( 162 ) HTML (1 KB) PDF (626 KB) ( 236 )

	852	Improved ICP Algorithm Based on Normal Vector Weight
		ZHU Yu-mei,XING Ming-yi,CAI Jing
		DOI: 10.3969/j.issn.1000-1158.2023.06.03
		Aiming at the problem that the accuracy and speed of point cloud registration in the process of 3D reconstruction are not ideal, an iterative nearest point (ICP) algorithm based on normal vector weight improvement is proposed. By projecting the normal vector of the point cloud onto the Gaussian sphere, the distribution of normal vectors in different directions is counted, the corresponding weight is assigned by combining the geometric structure information of the object, and the normal vector weight combined with the error measurement method from point to plane is used to calculate the optimal rigid body transformation matrix. Experimental results show that taking spherical point cloud data as an example, compared with the iterative closest point (ICP) algorithm before improvement, the registration error is reduced to about 30% without reducing the registration speed, and the algorithm is suitable for various point cloud models with significant effects.
		2023 Vol. 44 (6): 852-857 [Abstract] ( 174 ) HTML (1 KB) PDF (498 KB) ( 507 )

	858	Study on the Measuring Method of Two-point Sizes for Revolving Body Based on the Roundness/Cylindricity Measuring Instrument
		ZHAO Ze-xiang,WANG Shuai-fei,ZHAO Xin-yu
		DOI: 10.3969/j.issn.1000-1158.2023.06.04
		A measuring method of two-point size for revolving body based on the roundness/cylindricity measuring instrument was proposed. The model of the measurement system error for the radial size of the roundness/cylindricity measuring instrument was built based on the calibrated diameter of a standard cylinder. A new coordinate system was established by taking the center of the least square circle as its origin and the line connecting the center of the least square circle with the first sampling point as the x axis. Through coordinate translation and rotation, the coordinates of the sampling points in the original coordinate system were converted to the coordinates in the new coordinate system, and the corresponding polar coordinate values were converted. Based on the polar coordinate values above, their cubic spline interpolation equation for determining the two-point sizes of revolving body was built, and the flow chart of measuring and evaluating two-point size for revolving body was given. The evaluation of two-point sizes of the profiles of the cylinder features extracted on the cylindricity instrument was carried out by using the developed program. The mentioned research will provide a feasible measurement method for measuring two-point sizes of revolving body, which accords with the definition of the two-point size in GB/T 24637.3.
		2023 Vol. 44 (6): 858-864 [Abstract] ( 130 ) HTML (1 KB) PDF (629 KB) ( 138 )

	865	A Technique for Direct Measurement of UV Output of UV-LED with KI/KIO3 Chemical Actinometer
		ZHANG Lian-feng,ZHOU Yu,CHANG Bao-yan,XION Dong,YAN Jian-chang,SHEN Cong-min,WANG Chun-yong
		DOI: 10.3969/j.issn.1000-1158.2023.06.05
		UV-LED is a new generation of UV source, and its UV output is the key parameter. In order to measure the UV output of a UV-LED, a method to use a chemical actinometer to capture all of UV photons from UV-LED is proposed. The total energy of all photons captured in a certain time is the UV output. Since chemical actinometer is liquid, a vortex can be formed by rotation, and then a UV-LED is set inside the vortex. In such a case, UV-LED doesn’t touch the liquid, and the liquid captures all of photons from the UV-LED. Consequently, the UV output of a UV-LED can be accurately measured. In the process of the measurement, the heat generated by UV-LED is led to a water tank to keep the junction temperature of UV-LED to be stable. The KI/KIO3 actinometer is controllable through careful operations. The experimental results indicate that the discrete coefficients of the experimental data are in the range of 0.02~0.079.
		2023 Vol. 44 (6): 865-870 [Abstract] ( 119 ) HTML (1 KB) PDF (431 KB) ( 96 )

	871	Study on Measuring Thermal Conductivity of Materials at High Temperature by Guarded-hot-plate
		LIU Ye,ZHANG Jin-tao,WANG Jin-ku,WANG Ming-kai,SUN Jian,XU Hong-wei
		DOI: 10.3969/j.issn.1000-1158.2023.06.06
		Guarded-hot-plate (GHP) method plays the primary procedure for measurements of the thermal conductivity of insulators. The method has important applications in the fields of new material explorations and industrial energy savings. The National Institute of Metrology(NIM) has newly developed a single sample high temperature protection hot plate method device, the design working temperature ranges from room temperature to 500 ℃, and the thermal conductivity measurement range is 0.02～0.5W/(m·K). We developed a new controlling scheme that effectively suppressed the thermal oscillation caused by the thermal inertia of the big equipment ensemble. The temperature of each component of the device is continuously stablized within 0.005℃ in a period up to 2 hours. The heat leak from the upper guarded plate is a specific question with the GHP devices of the single sample type. The phenomenon become serious with increasing temperatures. We studied the temperature compensation procedure that effectively suppresses the heat leak through the upper guarded plate. We applied the device measuring the standard reference material for thermal conductivity of SRM1450d of NIST, in the sample average temperature from 30℃ to 70℃, the relative deviation from the reference values falls in the range of 0.2%～1.9% with the measurement uncertainty of 1.2% (k=2). We used the device measuring the thermal conductivity of cast polymethyl methalcylate, and observed the relative deviation of -0.8% to -1.5% from the publication data by the PTB. We then measured the thermal conductivity of mineral wool in the temperatures ranging from 40~ 400℃ with the measurement uncertainty of 4.7% (k=2 ).
		2023 Vol. 44 (6): 871-877 [Abstract] ( 120 ) HTML (1 KB) PDF (504 KB) ( 169 )

	878	A Study on the Thermal Calibration Experiment of Irradiated SiC Crystal Temperature Sensors
		LEI Jian,LI Yang,CUI Han-xiao
		DOI: 10.3969/j.issn.1000-1158.2023.06.07
		Irradiated silicon carbide (SiC) temperature sensing is a major diagnostic technique for turbine blades in the process of aero-engine development. Its measurement accuracy depends on the accurate calibration of its response relationship between temperature and its defect concentration. The entire calibration process consists of the temperature calibration experiment, crystal defect characterization and calibration curve identification. The temperature calibration deviation caused by the fluctuation of the temperature field in the calibration test is an important source of the measurement error of the irradiation thermometer crystal. The dominant heat and mass transfer mechanism during the calibration process were studied by experimental and numerical methods, and the effects of the thermophysical parameters of the strut material, temperature overshoot, and temperature disturbance in the quasi thermal equilibrium state on the temperature sensitivity of the temperature measuring crystals were analyzed. The research results found that the measurement error was governed by the non-uniform distribution of thermal radiation field in the axial direction. Finally, the corresponding improvement plans were proposed to improve the geometric configurations and material selection of struts, and to optimize the choice of thermocouples in the calibration procedure of irradiated SiC crystal sensors.
		2023 Vol. 44 (6): 878-885 [Abstract] ( 148 ) HTML (1 KB) PDF (670 KB) ( 111 )

	886	Research on Measurement Uncertainty of Dynamic ResponseCharacteristics of Ocean Temperature Sensor Based on LSM
		WANG Peng-peng,ZHAO Shi-wei,MENG Wen-rong,YE Song
		DOI: 10.3969/j.issn.1000-1158.2023.06.08
		According to the requirements of dynamic response characteristics test of ocean temperature sensors, the time constant of typical ocean temperature sensor was tested through the time constant measuring device of hydrological sensor, and the characteristics of time constant were analyzed, the measurement results of time constant based on least square method(LSM) were comprehensively analyzed according to the principle of measuring device. The results show that the time constant has nothing to do with the temperature step, and the time constant and motion speed of different types of sensors meet different functional relations, which can be used to characterize the time constant characteristics of the sensor. Within the range of 0.5~ 3.0m/s, the relative expanded uncertainty of time constant measurement results is better than 10.2%, which is equivalent to the maximum allowable error of ±10%, meeting the performance requirements of time constant measurement device of hydrological sensor. The temperature fluctuation and uniformity of the water tank are the main sources of uncertainty. Creating an ideal step environment and maintaining the stability of the test environment can effectively reduce the uncertainty components introduced by the initial voltage, initial time and time constant, and the measurement accuracy of dynamic characteristics can be improved. The research results can provide technical reference for the development, testing and dynamic calibration technology of ocean temperature sensors.
		2023 Vol. 44 (6): 886-892 [Abstract] ( 163 ) HTML (1 KB) PDF (514 KB) ( 307 )

	893	Flow Pattern Identification of Gas-Liquid Two-phase Flow Based on Deep Forest and Electrical Resistance Tomography
		ZHANG Li-feng,TONG Tong,XIAO Kai
		DOI: 10.3969/j.issn.1000-1158.2023.06.09
		A flow pattern identification method of gas-liquid two-phase flow based on deep forest algorithm and electrical resistance tomography (ERT) was proposed. Firstly, ERT experimental device was used to collect data of four typical flow patterns, and the collected data was preprocessed by averaging multi-frame data. Then, some proper basic classifiers were selected to construct a deep forest model, and the maximum number of layers of the model was adjusted to ensure the accuracy of classification. Finally, the validity of multi-frame data averaging and the flow pattern identification ability of deep forest model were verified, and compared with two traditional deep learning algorithms, deep neural network and convolutional neural network. The results show that the accuracy of flow pattern identification of deep forest is better than that of other two algorithms, and the average identification accuracy can reach 98.75%. The preprocessing method of multi-frame data averaging is more conducive to flow pattern identification.
		2023 Vol. 44 (6): 893-898 [Abstract] ( 142 ) HTML (1 KB) PDF (594 KB) ( 193 )

	899	Research on Dynamic Calorific Assignment Method of Multi-gas Source Natural gas Pipeline Network
		WANG Yan-bing
		DOI: 10.3969/j.issn.1000-1158.2023.06.10
		Based on the hydraulic calculation method for dynamic simulation of gas pipeline network, the mixed transmission node traffic allocation solution method and heat dynamic assignment method are coupled, and the implicit difference method is used for numerical solution. Based on the above method, the calorific assignment software of the multi-source natural gas pipeline network is compiled, and the calorific assignment calculation is carried out. It is verified that the error between the calculated natural gas calorific value and the measured results is within 0.36%, which meets the maximum tolerance requirements of GB/T 18603 ‘Technical Requirements for Natural Gas Metering Systems’. The method realizes the functions of temperament tracking and dynamic calorific value assignment of multi-gas source natural gas pipeline network.
		2023 Vol. 44 (6): 899-906 [Abstract] ( 127 ) HTML (1 KB) PDF (583 KB) ( 284 )

	907	Modeling and Simulation Analysis of Multi-DOF Automotive EPS Load Resistance Torque Characteristics
		ZHOU Qi,FAN Wei-jun,GUO Bin,LUO Zai,PAN Yin-bin
		DOI: 10.3969/j.issn.1000-1158.2023.06.11
		In order to study the electric power steering(EPS) stress state in the nonlinear complex system composed of roads, tires, vehicles, etc., starting from the EPS rack and pinion steering mechanism, combined with the unified tire (UniTire) model, the vehicle 7-DOF dynamics model and the front wheel alignment parameters, an EPS load resistance torque model based on the 7-DOF vehicle steering model is established to analyze the variation characteristics of EPS load resistance torque under different vehicle speeds and steering wheel angles, the multi-DOF modeling and simulation are carried out through MATLAB/Simulink software. Finally, the double lane-change simulation experiment and steering transient response simulation experiment are carried out. The experimental results show that compared with the 3-DOF vehicle steering model, the model can better reflect the variation characteristics of the vehicle EPS load resistance torque with the steering wheel angle under different vehicle speeds.
		2023 Vol. 44 (6): 907-916 [Abstract] ( 162 ) HTML (1 KB) PDF (986 KB) ( 388 )

	917	Study on Compaction Characteristics of Particle Based on Discrete Element Method
		CHEN Chao-yun,WEN Hui-qing,LIANG Yan-zheng
		DOI: 10.3969/j.issn.1000-1158.2023.06.12
		In order to solve the particle pressure of the particle pressure, the relationship between the physical characteristics and dynamic response of the particles and the lack of mathematical models are characterized by mechanical behavior. For the relationship between the physical properties and dynamic response of particles during compaction and densification, there is a lack of mathematical models to characterize the mechanical behavior. Based on the discrete element method (DEM), two models of vibration and rotation are established to describe the density mechanism of particle pressure. In order to facilitate the analysis of the changes in the process of particles and the filling effect, the actual size of the particles is magnified, and the vibration and transmission rotation experiments of the dice in the cylindrical describer are designed to explore the dynamic characteristics of the compact particles. The research results show that: with the amplitude of 15mm and the frequency of vibration is 1~5Hz, the particles will stay in the semi orderly arrangement state for a long time. Only when the amplitude is reduced to 10mm at a slow time, and the frequency to 3Hz, the complete orderly arrangement state can be achieved. When the acceleration of the transmission rotation is greater than 0.5g, the particles can reach an orderly arrangement state without intervention.
		2023 Vol. 44 (6): 917-922 [Abstract] ( 146 ) HTML (1 KB) PDF (623 KB) ( 94 )

	923	A Meta Generactive Instinsic Reward Based Robot Manipulation Skill Learning
		WU Pei-liang,QU You-yuan,LI Yao,CHEN Wen-bai,GAO Guo-wei
		DOI: 10.3969/j.issn.1000-1158.2023.06.13
		To address the problem of low learning efficiency for complex tasks under sparse rewards, a meta generative intrinsic reward (MGIR) algorithm was proposed based on the idea of off policy reinforcement learning. And it has been applied to the problem solving of robot operation skills learning. The specific steps were to first use a meta generated intrinsic reward framework that can decompose complex tasks into multiple subtasks, and evaluated the ability of subtasks. Then, an internal reward module was introduced to generate the novelty of the state explored by the agent as an internal reward. And jointly guided intelligent agents to explore the environment and learn specific tasks through environmental rewards. Finally, comparative experiments were conducted on offline strategy reinforcement learning in the MuJoCo simulation environment Fetch.The experimental results showed that the proposed meta-generated intrinsic reward algorithm performs better both in terms of training efficiency and success rate.
		2023 Vol. 44 (6): 923-930 [Abstract] ( 131 ) HTML (1 KB) PDF (761 KB) ( 227 )

	931	Analysis of Transient Cavitation Flow and Pressure Pulsation of Guide Vane Centrifugal Pump
		WANG Hao,LI Lin-wei,MOU Cheng-qi,ZHOU Pei-jian,WU Deng-hao
		DOI: 10.3969/j.issn.1000-1158.2023.06.14
		The RNG k-ε turbulence model and the Zwart-Gerber-Belamri cavitation model are used to numerically simulate a guide vane centrifugal pump, and the internal pressure pulsation spectrum curve is obtained. The results show that the pressure pulsation peak-to-peak value of the impeller monitoring point gradually decreases along the flow direction, and the main frequency is 8 times the rotation frequency and its multiplication frequency. With the intensification of cavitation, the peak-to-peak value of impeller pressure pulsation gradually decreases. The main frequencies of the pressure pulsation of the forward and reverse guide vanes are both the vane frequency and its multiplier, and the amplitude increases with the development of cavitation. The cavitation in the axial direction shows that the cavitation volume fraction gradually increases from the front cover plate to the rear cover plate of the impeller. The dynamic and static interference between the impeller and the positive guide vane causes periodic changes of the flow field in the impeller, resulting in periodic fluctuations in the pressure pulsation.
		2023 Vol. 44 (6): 931-938 [Abstract] ( 124 ) HTML (1 KB) PDF (1005 KB) ( 99 )

	939	Prediction of the Remaining Useful Life of Lithium-ion Batteries Based on PF-LSTM
		WU Zhong-qiang,HU Xiao-yu,MA Bo-yan,HOU Lin-cheng,CAO Bi-lian
		DOI: 10.3969/j.issn.1000-1158.2023.06.15
		In order to solve the problem that it is difficult to accurately predict the remaining useful life (RUL) of lithium battery, a prediction model of improved long-term and short-term memory network based on particle filter (PF-LSTM) considering various life decay characteristics and data sequence is proposed and applied to the RUL prediction of lithium battery.The health factors closely related to the capacity decline are extracted from the battery historical charge and discharge aging data as the input of the LSTM network, and the global optimization ability of the PF algorithm is used to find the optimal parameters, including the number of neurons, learning rate, node abandonment rate, batch size, training steps and other six parameters to improve the prediction ability of the network; the introduction of Dropout layer to avoid network over-fitting and improve the generalization ability of the model.Based on the experimental verification of NASA PCoE battery data set, the capacity estimation and life of four batteries under different prediction starting points are predicted and compared with LSTM, SVR searched by grid and other algorithms.The experimental results show that the root mean square error RMSE and the average absolute error MAE of PF-LSTM capacity estimation are less than 2%, and the life prediction error is less than 3 cycles, which is the highest compared with other algorithms.
		2023 Vol. 44 (6): 939-947 [Abstract] ( 188 ) HTML (1 KB) PDF (768 KB) ( 451 )

	948	The Comparative Study of Curve-fit Methods for Partial Period Sine Waves
		LIANG Zhi-guo
		DOI: 10.3969/j.issn.1000-1158.2023.06.16
		Aiming at both the frequency search method and the combination method, the shortest cycles of the sinusoidal curve fit method can achieve in the actual fit, which is carried out in two sampling sequences of both single-precision floating point data and double precision floating point data. By searching for change signal cycles of sequence, the sampling data number, the waveform initial phase, simulation experiment has been studied. The variation laws of the sinusoidal parameters of curve-fitting have been presented, the conclusions obtained are: 1) For single-precision floating point data sequence, under any phase conditions, the frequency search method can obtain available results under 10% waveform cycle curve, and the combination method can obtain available results in a 7% waveform cycle curve; on the best conditions near the zero point, 1% cycles curve can be performed for good fitting results. 2) On the double precision floating point data sequence, in any phase condition, the frequency search method can obtain available results under 7% waveform cycle curve, and the combination method can obtain available results at 4% waveform cycle curve; near the zero point, the combination method can perform residual period fitting of 0.03% periodic curves.
		2023 Vol. 44 (6): 948-955 [Abstract] ( 169 ) HTML (1 KB) PDF (759 KB) ( 82 )

	956	Estimation of Safety Coefficient of the Logarithmic Evaluation Method of Uncertainty in Electromagnetic Compatibility Test
		HUANG Jie-yi,LUO Zai,CHENG Yin-bao,WU Jun,YUAN Ke-feng
		DOI: 10.3969/j.issn.1000-1158.2023.06.17
		With the popularization of electromagnetic compatibility certification, the discussion on measurement uncertainty in the electromagnetic compatibility field is increasing.At present, there are still controversies about the use of logarithmic units and linear units in electromagnetic compatibility tests, and there is also no reference standard for the evaluation of logarithmic units in GUM.In view of this situation, through the discussion of lognormal and linear normal, a safety factor estimate t related to the logarithmic unit standard deviation and the value of the number of measurements is obtained.Taking the mean value of the logarithmic unit evaluation as the final benchmark, the safety factor can extend the evaluation interval of the lognormal distribution, so that the evaluation result can be expanded as small as possible, and the evaluation result of the linear unit can be fully included.After eliminating the dispute between the linear unit and the logarithmic unit in the evaluation result, the uncertainty result is safer and more reliable.
		2023 Vol. 44 (6): 956-961 [Abstract] ( 119 ) HTML (1 KB) PDF (435 KB) ( 288 )

	962	Research on Overall Calibration Method of PCM Equipment Capacitance Parameters
		QIAO Yu-e,LIU Xia-mei,DING Chen,ZHU Chao,WU Ai-hua
		DOI: 10.3969/j.issn.1000-1158.2023.06.18
		Process control monitor (PCM equipment) is widely used in the semiconductor industry. It is necessary in the intermediate test of chip products. The accurate measurement of capacitance parameters of PCM equipment is an important mean to ensure the process parameters related to capacitance manufacturing. Since there is no traceability for the capacitance parameters of domestic PCM equipment at present, after the characteristics of the capacitance parameters test process of PCM equipment has been analyzed, a nondestructive calibration method based on on-wafer capacitor standards is studied. The on-wafer capacitor standards with a value low to 0.5pF is developed by using semiconductor single chip process and the maximum frequency is 1MHz, which meets the requirements of the whole automatic calibration of the capacitance parameters of the domestic equipment. The measurement uncertainty is better than 1%, and the stability is better than 0.2%. The traceability method from capacitor parameter of PCM equipment to the highest national/national defense standards, so as to ensure the accuracy and consistency of the measurement results of PCM graphic capacitance of chip products, and improve the periodic inspection efficiency.
		2023 Vol. 44 (6): 962-967 [Abstract] ( 138 ) HTML (1 KB) PDF (566 KB) ( 149 )

	968	Design of Water Quality Monitoring System Based on Fish Activity Bioelectrical Signals
		YANG Ling-sheng,LI Wei1,YOU Jia-qi,ZHU Xiao-lei
		DOI: 10.3969/j.issn.1000-1158.2023.06.19
		The fish analysis is the main direction of biological monitoring of water quality at present.Aiming at the problems such as weak strength of the fish bioelectric signal, easy to be interfered by noise, and lack of effective determination basis of fish water quality monitoring sensor.Filtered and increased the fish bioelectric signal collected by the observation electrode.Then through MCU MSP430 to collect and convert the signal, while in the upper computer based on Labview program, the power spectral density of various active potential signals (breathing and swimming movement) of the fish were calculated respectively to realize the frequency domain analysis of the bioelectrical signals of the fish.Then, combining with the new criterion of whether the variation of various movement power proportions exceeds the threshold value, the early warning judgment was completed.Finally,the effectiveness of the system had been proved by experiments.
		2023 Vol. 44 (6): 968-974 [Abstract] ( 119 ) HTML (1 KB) PDF (838 KB) ( 379 )

	975	Uncertainty Analysis of Measurement of Wide Distributed Particle Size Based on Microscopic Image Method and Numerical Simulation
		JIANG You-xin,WU Li-min,ZHOU Wu,XU Ri-xin,CAI Xiao-shu
		DOI: 10.3969/j.issn.1000-1158.2023.06.20
		With the introduction of the concept of reference material with wide particle size distribution, its determination method also needs to be clarified. For the processing and uncertainty of electron microscopic images of standard materials with wide particle size distribution, firstly, a method for boundary recognition of spherical particle images based on Hough transform circle detection was adopted to realize the correct segmentation of adhered particle images;and secondly, through numerical simulation the uncertainty of the measured value of Dv50 introduced by the number of samples was determined by the method,and the feasibility of the mentioned method was verified through comparative analysis with relevant standards; finally, the method of obtaining the uncertainty of the average particle size of the particle system from the particle size uncertainty of a single particle was proposed, and the particle size distribution range of 1~18μm was obtained. The uncertainty evaluation of glass bead particles was carried out, and the relative expanded uncertainty was 1.613%(k=2).
		2023 Vol. 44 (6): 975-980 [Abstract] ( 233 ) HTML (1 KB) PDF (501 KB) ( 180 )

	981	Quantitative Study of Laser Methane Concentration Based on Support Vector Machine
		CAO Quan-wei,TU Cheng-xu,XU Hao-hao,BAO Fu-bing,LI Xiang,SHEN Jia-yuan
		DOI: 10.3969/j.issn.1000-1158.2023.06.21
		It is important to detect methane gas and quantify methane concentration accurately based on tunable semiconductor laser absorption spectroscopy (TDLAS).Due to the weak laser methane signal, the traditional methane concentration quantification model has the problem of large quantization error under complex working conditions.To solve this problem, a quantitative regression model of laser methane telemetering concentration was built based on radial basis RBF-nu-SVR, and was compared with the traditional model, polynomial kernel and linear kernel nu support vector regression, BP neural network and other models.In the results, the RBF-nu-SVR model built showed strong generalization performance on the test set.The average absolute percentage error (MAPE) and Pearson correlation coefficient (R2) were 9.155 and 0.99947 respectively, which improved the detection accuracy of TDLAS for methane gas.Because the original data was used, it was unnecessary to extract the second harmonic, thus simplifying the structure.
		2023 Vol. 44 (6): 981-985 [Abstract] ( 170 ) HTML (1 KB) PDF (538 KB) ( 425 )

	986	Preparation of Cucumber Green Mottle Mosaic Virus in Seed Powder Matrix Reference Material
		YIN Xin-ying,XU Yi-ling,LIU Yi-luan,ZHANG Yi,LU Zhong-ting,YAN Shuang,CAO Ji-juan
		DOI: 10.3969/j.issn.1000-1158.2023.06.22
		Seed powder matrix reference materials for cucumber green mottle mosaic virus were developed in this study to resolve the problem of lack of qualitative standard sample. Seed batches of Cucurbita pepo L. naturally infected with CGMMV were used as raw materials. After the specificity identification and confirmation, CGMMV reference materials of Cucurbita pepo L. seed powder matrix were prepared, which has been confirmed by double antibody sandwich enzyme-linked immunosorbent (DAS-ELISA) assay and real-time fluorescence quantitative RT-PCR (RT-qPCR) method.The results demonstrated that the reference materials were stable. After the samples were certified by using collaborative characterization program with eight sophisticated participating laboratories, Shapiro Wilk test showed that the standard sample conforms to Normal distribution.Seed power matrix reference materials were certified contained CGMMV by Grubbs method. Based on above results, the matrix reference materials in accordance with the requirements of the national reference material, it can be used for laboratory quality control, capability verification, testing method verification, and other activities.
		2023 Vol. 44 (6): 986-991 [Abstract] ( 126 ) HTML (1 KB) PDF (510 KB) ( 98 )

	992	Advances in the Biological Effects of Exosomes on Tumors and Their Detection Methods
		SONG Yu-meng,ZHAI Rui,LEI Xi-mei,CHU Zhan-ying,ZHU Man-man,FAN Xiao-xue,YE Zi-hong,DAI Xin-hua,FANG Xiang
		DOI: 10.3969/j.issn.1000-1158.2023.06.23
		Exosomes are tiny vesicles secreted by cells, which contain important biologically active substances such as proteins, lipids, and nucleic acids. As an important carrier of cell-to-cell communication, exosomes directly participate in the occurrence and development of tumors in the body, and by affecting the tumor microenvironment, they mediate the growth and migration of tumor cells. Due to the special physiological functions of exosomes, in recent years, there has been an increasing number of studies using them as treatment vectors and biomarkers for major diseases, and the detection methods for exosomes have also been continuously developed. A systematic review was conducted on the recent research of the biological functions and detection of exosomes from tumor cells, and the development trend of detection methods was prospected.
		2023 Vol. 44 (6): 992-999 [Abstract] ( 144 ) HTML (1 KB) PDF (796 KB) ( 647 )

	1000	Research Progress on Detection Technology of Meat Adulteration
		LU Yu-xuan,ZHAI Rui,WU Fan,CHU Zhan-ying,ZHU Man-man,WU Li-qing,JIANG You,DAI Xin-hua,FANG Xiang,YE Zi-hong
		DOI: 10.3969/j.issn.1000-1158.2023.06.24
		The quality inspection of meat and its products is an important guarantee for food safety. In the past few decades, nucleic acid detection technology, biosensor, spectroscopy detection technology, immunology detection technology and mass spectrometry technology have been used for meat adulteration, which can accurately and rapidly detect the composition and content of main meat and its products on the market. And the development and application of relevant reference materials will further improve the accuracy and reliability of these test methods. A comprehensive analysis and review of the main methods for meat adulteration analysis are conducted, and the advantages and disadvantages of these technologies in meat adulteration detection are summarized.At the same time, the development trend of adulteration detection of meat and its products is discussed and forecasted, in order to provide a certain reference value for the improvement and regulation of my country's meat market.
		2023 Vol. 44 (6): 1000-1008 [Abstract] ( 131 ) HTML (1 KB) PDF (510 KB) ( 457 )

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