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2022 Vol. 43, No. 12
Published: 2022-12-28
 
1533 The Principle and Prospect of AC Power Standards
BAI Jing-fen,MENG Jing,ZHAO Dong-fang,LI Shi-song,DUAN Mei-mei
DOI: 10.3969/j.issn.1000-1158.2022.12.01
As the core element for electrical energy traceability, AC power standards play a crucial role in ensuring fair and equitable electrical energy trade settlement. The methods commonly used to construct high-precision AC power standards and the related traceability paths are summarized. The major measurement uncertainty components during the calibration of the electric energy meters via different the AC power standards are analyzed. By reviewing the technical aspects in existing AC power standards and the new requirements of power system measurement, the future development trends for electric power and energy standards are prospected.
2022 Vol. 43 (12): 1533-1537 [Abstract] ( 200 ) HTML (1 KB)  PDF (1233 KB)  ( 519 )
1538 Self-correction Method of Rolling Angle Measurement Error for Linear Guide Rail
DOI: 10.3969/j.issn.1000-1158.2022.12.02
The precision of parallel dual-beam method is greatly affected by the beams’ parallelism when measuring a roll angle error, a five-degree-of-freedom motion error measurement system with self-correction function for roll angle measurement is proposed. The principle of a five-degree-of-freedom measuring system using double beam method is introduced, the model between double beam parallelism error and the roll angle measuring error is achieved, double autocollimator based method for monitoring the parallelism is proposed. The experimental results show that the residual error of the measured roll angle error can be reduced from 44″ to 2.7″ when a parallelism error of 15.4″ exists. The accuracy of the double-beam measurement for roll angle error has been improved effectively. The proposed method can be used to monitor the motion error of linear guides in real time.
2022 Vol. 43 (12): 1538-1543 [Abstract] ( 191 ) HTML (1 KB)  PDF (2333 KB)  ( 164 )
1544 10μm Lattice Sample for Scanning Electron Microscope Calibration
ZHANG Xiao-dong,ZHAO Lin,LI Suo-yin,HAN Zhi-guo,XU Xiao-qing,WU Ai-hua
DOI: 10.3969/j.issn.1000-1158.2022.12.03
Scanning electron microscope (SEM) is an important instrument for critical dimension measurement in the semiconductor field. In order to ensure the accuracy and consistency of the instrument value, the SEM needs to be calibrated. First of all, for the orthogonal distortion and linear distortion parameters mentioned in the calibration specification, a lattice sample with a nominal value of 10μm is developed by using semiconductor technology. Secondly, in order to accurately evaluate the consistency of lattice features, a rectangle detection algorithm is studied. During the measurement process, the algorithm is used to measure the lattice features of the sample, and the measurement data obtained by the atomic force microscope (AFM) is used as the reference value. The experimental results show that the rectangle detection algorithm can detect the lattice features quickly, and the test data is stable within 6nm. In addition,the developed lattice sample has good consistency,and the consistency parameters are controlled within 0.2,which can applied to the calibration of SEM.
2022 Vol. 43 (12): 1544-1548 [Abstract] ( 167 ) HTML (1 KB)  PDF (2239 KB)  ( 332 )
1549 Tracking Type Line Width Standard Sample Based on Multilayer Film Deposition
ZHAO Lin,HAN Zhi-guo,ZHANG Xiao-dong,XU Xiao-qing,LI Suo-yin,WU Ai-hua
DOI: 10.3969/j.issn.1000-1158.2022.12.04
In order to realize the calibration of critical dimension measuring instruments in the semiconductor industry, research work on nano-size line width standard samples has been launched.The nano-size line width standard samples with sizes of 20nm and 50nm were prepared by multi-layer film deposition technology.Aiming at the problem that it is difficult to find out when calibrating due to the small overall size of the standard template and the small measuring field of view of the instrument, and the problem that the quality of the template line edge leads to too large difference in the results of different positions measured each time, the positioning and tracking signs were designed. A total of 9 groups of signs were designed, each group of signs had 9 marker grids, the width of each sign was 0.5μm, and the interval of the signs was 2.5μm, the distance between each group of marks was 100μm.The semiconductor process can quickly and accurately find the standard measurement position, ensure the repeatability of each measurement result, and effectively improve the measurement speed and accuracy.
2022 Vol. 43 (12): 1549-1553 [Abstract] ( 178 ) HTML (1 KB)  PDF (1904 KB)  ( 149 )
1554 Research on Interpolation Method for Obtaining DEM of Material Pile Based on Millimeter Wave Radar
KONG De-ming,CAO Shuai,SHEN Yue,ZHOU Yi-ren
DOI: 10.3969/j.issn.1000-1158.2022.12.05
Aiming at the problems of difficulty in obtaining stack height model, poor environmental adaptability of measuring device, high cost and low model accuracy in the development process of the existing automatic stacker-reclaimer technology, the use of 77GHz millimeter wave radar, differential BeiDou and angle coding is proposed. The integrated technology of the device obtains discrete point cloud data on the surface of a large stockpile. Derive a formula for solving multi-sensor data fusion to obtain discrete point cloud data. It is proposed to use the hybrid quantized pigeon-inspired optimization algorithm to optimize the Kriging interpolation algorithm to obtain the digital elevation model(DEM)of the stockpile. The method of cross-validation is used to compare and analyze the improved ordinary Kriging, ordinary Kriging, inverse distance weighting, linear and natural neighborhood interpolation algorithms based on triangulation after selecting the parameters. The root mean square error of the improved Kriging interpolation algorithm is less than 0.37m, the mean square error is less than 0.13m, and the root mean square error is 39.9% lower than the ordinary Kriging interpolation algorithm. During the on-site test, the proposed method can obtain the DEM of the pile without the influence of weather and dust, and it is meets the requirements of accuracy in the project of automatic pile-reclaimer.
2022 Vol. 43 (12): 1554-1560 [Abstract] ( 212 ) HTML (1 KB)  PDF (2348 KB)  ( 490 )
1561 Research on Thickness Measurement Method of Nuclear Heat Exchanger Plate Based on Line Laser Scanning
LIU Jie,ZHENG Xue-song,YANG Bin,WANG Gang,LI Wen-long
DOI: 10.3969/j.issn.1000-1158.2022.12.06
In order to realize the on-site rapid detection of the thickness and size of the nuclear power heat exchange plate, a line laser three-dimensional measurement system is builded for the thickness detection of complex thin-walled parts. According to the digital model and the constantly changeable surface curvature of the heat exchange plate, the thickness calculation method based on the distance between points and the spatial clustering is proposed to realize the efficient calculation of its thickness. The experimental result shows that the measurement accuracy of the system is better than 0.15mm, the inspection time is less than 2min, and the calculated average thickness of the heat exchange plate is 0.9921mm, which can meet the enterprises on-site (measurement accuracy is better than 0.2mm, inspection time ≤5min) inspection requirements.
2022 Vol. 43 (12): 1561-1567 [Abstract] ( 166 ) HTML (1 KB)  PDF (3444 KB)  ( 191 )
1568 Experimental Study on Lovibond Color System
GAO Hong-bo,ZHOU Yan,ZENG Li-Mei,WU Wei-gang
DOI: 10.3969/j.issn.1000-1158.2022.12.07
In order to solve the metrological traceability of Lovibond color system, a spectro-photometric method is proposed to study the Lovibond color system. The analysis of experimental data shows that there is an obvious linear relationship between the spectral density and the Lovibond number at single wavelength, in the wavelength range of 380～780nm, the relationship between the integral optical density and the number of Lovibond is also obvious. The reliability of the relationship is verified by the data provided by the American Oil Chemists Society.
2022 Vol. 43 (12): 1568-1572 [Abstract] ( 179 ) HTML (1 KB)  PDF (1048 KB)  ( 122 )
1573 Pedestrian Re-identification Method Based on Asymmetric Enhanced Attention and Feature Cross Fusion
JIN Mei,LI Yuan-yuan,HAO Xing-jun,YANG Man,ZHANG Li-guo
DOI: 10.3969/j.issn.1000-1158.2022.12.08
In order to solve the problem of poor retrieval accuracy due to the lack of sufficient and recognizable feature information extracted by the existing pedestrian re-identification methods, a pedestrian re-identification method based on the asymmetric enhanced attention and feature cross fusion is proposed. First, an asymmetric enhanced attention module is constructed, and the salient feature representation is enhanced through the cross-neighbor channel interactive attention that is aggregated by multiple pooling, so that the pedestrian area in the image is focused by the network. Then, taking into account the differences and relevance between the features of each layer of the network, a feature cross fusion module is constructed, and the cross fusion method is used to achieve cross-level fusion of features at different levels in the same layer, thereby realizing multi-scale fusion. Finally, the output features are segmented horizontally to obtain local features, so as to describe pedestrians in a specific area. The proposed method is verified on the three public data sets of Market1501, DukeMTMC-reID and CUHK03. Rank-1 reach 93.5%, 85.1% and 64.3% respectively, proving that the method is superior in improving the performance of pedestrian re-identification.
2022 Vol. 43 (12): 1573-1580 [Abstract] ( 181 ) HTML (1 KB)  PDF (2693 KB)  ( 517 )
1581 Analysis of Key Influencing Factors of Time Constant of Gas Flow Temperature Sensors
ZHAO Jian
DOI: 10.3969/j.issn.1000-1158.2022.12.09
Dynamic response calibration of gas flow temperature sensors was taken in the hot calibration wind tunnel, through which time constants of various temperature sensors under various working conditions were obtained, and key influencing factors were drawn such as diameter of welding ball, diameter of thermocouple wire, shield structure, gas flow Mach number, temperature and temperature step. Influencing mechanisms were anylised, and influencing laws of time constant were obtained. The results show that time constants can be decreased by decreasing diameter of welding ball, diameter of thermocouple wire, area ratio of shield inlet and outlet and temperature step, increasing gas flow Mach number and gas flow temperature, and using opposite opening structure of inlet and outlet. When diameter of thermocouple wire decreases from 0.8mm to 0.5mm, time constant decreases by 142.9%. The results can provide essential basis for design, use and dynamic compensation of gas flow temperature sensors.
2022 Vol. 43 (12): 1581-1586 [Abstract] ( 185 ) HTML (1 KB)  PDF (1918 KB)  ( 140 )
1587 Research on Detection of Combustion Temperature Distribution Based on Smartphone APP
WANG Hao-fan,FU Rui,YUAN Yi,LI Zhi-cong,PU Yang,LOU Chun,WENG Can
DOI: 10.3969/j.issn.1000-1158.2022.12.10
To measure flame temperature distribution, a method based on the Android system using heat radiation theory and visible light image processing was proposed. The camera of the smartphone was used to collect the visible light image of the flame. After extracting the RGB of each pixel of the visible light image and calibrating the smartphone camera to determine the quantitative relationship between radiation intensity and RGB, flame temperature of each pixel was measured using Wien’s law. The developed APP flame temperature measurement technology was allowed to input the combustion image by taking a photo or selecting a photo from gallery. Main parameters, such as exposure time, white balance and ISO etc, of the photo was extracted. A two-dimensional flame temperature distribution was generated after calculation. An experiment was set to measure the temperature distribution of the inverse diffusion flame. The result showed that the relative deviation of the maximum temperature measured by the smartphone was 4% compared with the multi-wavelength measurement method.
2022 Vol. 43 (12): 1587-1592 [Abstract] ( 193 ) HTML (1 KB)  PDF (2327 KB)  ( 499 )
1593 Numerical Simulation for the Dynamic Response Calibration of the Sheathed Thermocouple
LIU Bo,ZHENG Wei,WANG Zhi-yuan,LI Xue-jing
DOI: 10.3969/j.issn.1000-1158.2022.12.11
Time constant is one of the important parameters for temperature sensor`s dynamic response. Because the calibration conditions usually can`t cover the temperature sensors service conditions, the dynamic responses of a sheathed thermocouple under plunge test and loop current step response (LCSR) test were numerically simulated by the finite volume method. Three-dimensional structure models of the thermocouple with protective tube, insulating layer and sensing layer were established. The dynamic responses of the thermocouple with different MgO ratio in the insulating layer were analyzed. The results show that the time constants obtained by fitted and transformed LCSR data with the equation of three poles agree well with the time constants obtained by the plunge test, and the deviations are less than 10%. These provide a new method for the design and calibration of the fast response sheathed thermocouples.
2022 Vol. 43 (12): 1593-1597 [Abstract] ( 182 ) HTML (1 KB)  PDF (1954 KB)  ( 136 )
1598 Evaluation of Relative Temperature Measurement Performance of Thermal Imager for Unsteady Heat Transfer
LU Zhong-hai,WANG Xiao-na,HOU De-Xin,YE Shu-liang
DOI: 10.3969/j.issn.1000-1158.2022.12.12
The relative temperature measurement of thermal imager is widely used in the test field. Its time-varying characteristics, nonlinearity and radiation source size effect lead to the error of relative temperature measurement, which brings inconvenience to the uncertainty analysis of test results. Therefore, a performance evaluation method of relative temperature measurement of thermal imager is proposed. The thermal node of the sheet thermocouple is fixed on the surface of the heating unit with uniform temperature field as the standard radiation temperature generating unit. The thermal imager to be evaluated is observed and measured. The relative temperature measurement performance of the thermal imager is evaluated by comparing the similarity between the surface temperature field data of the thermocouple thermal node observed by the thermal imager and the temperature data measured by the thermocouple itself. Based on 7 thermal imagers with different specifications of 4 brands at home and abroad, the results show that the relative temperature measurement error and absolute temperature measurement error of the thermal imager are quite different, and the relative temperature measurement error is usually between the noise equivalent temperature difference and absolute temperature measurement error. At the same time, it is found that the performance of No.6 thermal imager is poor and the temperature drift is serious. The performance of the thermal imager is tested at the same time through the targets A and B in the device. The standard deviation of the evaluation results is less than 8%, which shows that the method has high reliability and has a certain reference significance for the evaluation of the relative temperature measurement performance of the thermal imager.
2022 Vol. 43 (12): 1598-1604 [Abstract] ( 159 ) HTML (1 KB)  PDF (2828 KB)  ( 136 )
1605 Calibration Method of On-Wafer Thin Film Platinum Resistance Temperature Sensor
XU Xiao-qing,LI Suo-yin,LIU Chen,ZHAO Xin-yu,ZHAO Ge-yan,WU Ai-hua
DOI: 10.3969/j.issn.1000-1158.2022.12.13
In the on-wafer thin film temperature sensor, platinum is used as the temperature sensing film, and is manufactured by semiconductor technology, which can effectively monitor the temperature of semiconductor devices on-wafer. In order to calibrate this type of temperature sensor, according to its working principle and structural characteristics, referring to the requirements of JJG 229-2010 for calibration device, a method is presented to set up a calibration device which consists of high and low temperature probe station, 8 1/2 digital multimeter and direct current probe. The resistance values of the temperature sensor are measured at different temperatures, and a scale of resistance temperature characteristics is obtained. The on-wafer thin film platinum resistance temperature sensor is calibrated at two temperature points of 25 ℃ and 125 ℃. The verification of calibration data and calibration result shows that the proposed method is feasible and can effectively solve the calibration problem of on-wafer thin film platinum temperature sensor without connecting leads. This calibration technique also provides a reference for other types of on-wafer temperature sensors.
2022 Vol. 43 (12): 1605-1609 [Abstract] ( 225 ) HTML (1 KB)  PDF (996 KB)  ( 660 )
1610 Influence of Hole-taking Method on Flow Measurement Results in Combination Total Pressure Tube
SAI Qing-yi,XIN Xu-chao,XU Hao-dong
DOI: 10.3969/j.issn.1000-1158.2022.12.14
For the application of combined total pressure pipe in flow measurement of large pipeline with diameter more than 1m, numerical simulation was carried out on the combination total pressure tube with different hole extraction methods (isocyclic method, Chebyshev method) and different amount of total pressure holes (2 pairs, 3 pairs and 4 pairs). The results indicate that the relative error of the measured results of the combination total pressure tube with 4 pairs of holes arranged by the Chebyshev method is small, which has the best effect. The combination total pressure tube was made according to the best hole-taking method,and the flow measurement test was carried out. The measurement results were compared with those obtained by the transverse method of Pitot static pressure tube. The results show that the deviation of two flow measurement methods is within±0.5%.
2022 Vol. 43 (12): 1610-1615 [Abstract] ( 150 ) HTML (1 KB)  PDF (2818 KB)  ( 135 )
1616 Detection of Gas-Liquid Interface Based on Array Ultrasonic Sensor
FANG Li-de,KONG Heng-zheng,HAN Bang-bang,TIAN Meng-yuan,LI Xiao-ting
DOI: 10.3969/j.issn.1000-1158.2022.12.15
Ultrasonic wave propagation in the fluid has the advantages of strong penetration, energy concentration, good directivity, and no disturbance to the flow field, so it has become an important means of two-phase flow parameter detection. Using the ultrasonic array detection technology of multiple transmitters and multiple receivers, the whole gas-liquid two-phase flow interface can be covered by ultrasonic, and the accuracy of measurement can be improved. Ultrasonic sensor array was used to study the gas-liquid interface under the relationship between the ultrasonic beam and the liquid surface, the experimental test results show that ultrasonic sensor array can realize the recognition of gas-liquid stratified flow state interface, also can realize the liquid level height detection, detection of surface displacement can be up to 2 mm, can also according to the ultrasonic echo signal to build the gas-liquid interface.
2022 Vol. 43 (12): 1616-1621 [Abstract] ( 216 ) HTML (1 KB)  PDF (2523 KB)  ( 382 )
1622 Identification of Two-phase Flow Pattern Based on 1D-CNN-AdaBoost and Electrical Resistance Tomography
ZHANG Li-feng,XIAO Kai,HUA Hui-chun
DOI: 10.3969/j.issn.1000-1158.2022.12.16
Based on the vertical tube gas-liquid two-phase flow measurement data collected by the electrical resistance tomography (ERT) system, the one-dimensional convolutional neural network (1D-CNN) and AdaBoost (Adaptive Boosting) are combined to construct the 1D-CNN-AdaBoost algorithm, a study on the flow pattern identification of gas-liquid two-phase flow has been carried out. The algorithm uses five 1D-CNNs as weak classifiers, trained on experimental data samples, and combined with AdaBoost to form the final strong classifier. Comparing 1D-CNN-AdaBoost algorithm with BP neural network, support vector machine and decision tree algorithm, the results show that the recognition accuracy of 1D-CNN-AdaBoost algorithm is higher than other algorithms, and the average recognition accuracy can reach 97%.
2022 Vol. 43 (12): 1622-1626 [Abstract] ( 170 ) HTML (1 KB)  PDF (2402 KB)  ( 153 )
1627 In-use Measurement of Ultrasonic Flowmeter Based on Machine Learning Algorithms
LI Meng-na,Lü Cheng-ze,WANG Lei,LI Chun-hui
DOI: 10.3969/j.issn.1000-1158.2022.12.17
Based on random forest algorithms, a prediction and analysis model of the in-use measurement of ultrasonic flowmeter is established to guarantee the accuracy of ultrasonic flowmeter. The study first establishes the in-use measurement procedure of the ultrasonic flowmeter. By obtaining data of the flowmeter signal index, flow rate characteristics,sound velocity and flow velocity etc., the flow deviation of ultrasonic flow meter is predicted by random forest algorithm, and the difference between predicated value and true value is smaller than 0.76%. Furthermore, the degree of influence for different factors on the accuracy of ultrasonic flowmeter are analyzed. The uncertainty of the model is evaluated, with extended uncertainty U=0.92%~0.22%(k=2).
2022 Vol. 43 (12): 1627-1633 [Abstract] ( 229 ) HTML (1 KB)  PDF (896 KB)  ( 299 )
1634 Primary Vibration Calibration of High Temperature Piezoelectric Acceleration Sensor
WANG Jia-hao,ZUO Ai-bin,PENG Yue-xiang
DOI: 10.3969/j.issn.1000-1158.2022.12.18
For the problem that the sensitivity of the piezoelectric acceleration sensor increases with the increase of temperature in a high temperature environment,a sine-approximation absolute calibration method for the acceleration sensor is proposed and a related experimental system is built.The sensitivity measurement and calibration test of the high temperature resistant acceleration sensor are carried out by the mentioned method under different temperature environments from room temperature to 400℃.The experimental results show that the sensitivity of the acceleration sensor shows a linear increase trend when the ambient temperature rises.
2022 Vol. 43 (12): 1634-1638 [Abstract] ( 176 ) HTML (1 KB)  PDF (1170 KB)  ( 127 )
1639 Accuracy Evaluation of Gravity Continuous Observation at Key Comparison Site of Absolute Gravimeter
MOU Li-shuang,FENF Jin-yang,WU Shu-qing,LI Chun-jian,WANG Qi-yu
DOI: 10.3969/j.issn.1000-1158.2022.12.19
The uncertainty of continuous observation results of superconduct gravimeter iGrav-012 at the comparison point of the global absolute gravimeter of National Insitute of Metrology is analyzed. The calibration factor of superconduct gravimeter is -927.96(nm/s2)/V, and the uncertainty is 0.80(nm/s2)/V. The uncertainty of continuous observation results of superconduct gravimeter introduced by the calibration factor is 3.20 nm/s2. After 5.5 years′ observation at the same site of superconduct gravimeter and absolute gravimeter, the drift rate of superconduct gravimeter is -14.66(nm/s2)/year, and the uncertainty is 2.1(nm/s2)/year. The uncertainty of continuous observation results of superconduct gravimeter introduced by the drift is 6.30nm/s2, and the uncertainty introduced by the two variables to the continuous gravity observation results is 7.07nm/s2.
2022 Vol. 43 (12): 1639-1644 [Abstract] ( 191 ) HTML (1 KB)  PDF (1968 KB)  ( 140 )
1645 Measurement of Diaphragm Tension of Condenser Microphone by X-ray Diffraction
LI Xu,HE Long-biao,ZHU Hai-jiang,ZHANG Xiao-li,FENG Xiu-juan,NIU Feng
DOI: 10.3969/j.issn.1000-1158.2022.12.20
To realize the direct measurement of the diaphragm tension of condenser microphones, the X-ray diffraction technology is adopted to measure microphone diaphragm with different tension. Comparing with the calculated tension value of the electrostatic excitation resonance method, the results show that two methods had the same trend and good consistency about the tension of microphone diaphragm. The resonant frequency calculated by the microphone frequency response includes the influence of the back cavity of the condenser microphone. Therefore, its measured value is slightly higher than the resonant frequency of the diaphragm itself. Therefore, the measured result of the X-ray diffraction method is slightly lower than the tension value calculated according to the resonant frequency. Finally, the influence of diaphragm tension on the electroacoustic characteristics of condenser microphone is verified by a series of tests.
2022 Vol. 43 (12): 1645-1650 [Abstract] ( 175 ) HTML (1 KB)  PDF (2052 KB)  ( 125 )
1651 Development of Phase Shifting Instrument Applied for Transformer Loss Calibration
LI Wei-jie,ZHAO Wei,SHAO Hai-ming,CAI Jin-Hui
DOI: 10.3969/j.issn.1000-1158.2022.12.21
Research on phase shifting technology and instrument were carried on, which was applied in a high voltage and current source with tunable power factor for the calibration of transformer loss measurement system (TLMS). The instrument was based on Hilbert Transform. Input signal was convolved to generate a quadrature signal, and then the output signal with required phase was generated with vector synthesis method. Based on the aboved research, a phase shifting device was built with Compact RIO platform. Meanwhile, a phase difference measurement instrument was developed, which combined signal acquiring and processing technology of Compact RIO and LabVIEW platform. Resolution and stability of the phase shifting device were also verified by a commercial phase angle voltmeter Clark-Hess 2600. The experimental results show that resolution, stability, and accuracy of the system resolution are all better than 0.001°.
2022 Vol. 43 (12): 1651-1657 [Abstract] ( 160 ) HTML (1 KB)  PDF (1939 KB)  ( 110 )
1658 Influence Analysis of Steady-state Solar Simulator Critical Parameters on Solar Cell Short-current Measurement
JIANG Fei-fei,LIU Hai-tao,YANG Lei
DOI: 10.3969/j.issn.1000-1158.2022.12.22
The classification standard of solar simulator performance grade is introduced. The influence of three key parameters of the steady-state solar simulator, namely, spectral matching degree, irradiation non-uniformity and irradiation instability, on the short-circuit current test results of photovoltaic cells is studied. The experimental results show that the spectral mismatch correction of solar simulator can reduce the deviation between the test value and the calibration value of short-circuit current; adjust the average irradiance in the effective test plane of the tested battery to meet the requirements of the standard value, which can effectively reduce the impact of the irradiation non-uniformity; controlling the irradiation instability of the simulator can reduce the repeatability test error of short-circuit current.
2022 Vol. 43 (12): 1658-1662 [Abstract] ( 162 ) HTML (1 KB)  PDF (1108 KB)  ( 123 )
1663 Experimental study on consistency optical evaluation and detection of gaseous element mercury calibration
ZHENG Hai-ming,ZHU Xiao-peng,JIA Gui-hong
DOI: 10.3969/j.issn.1000-1158.2022.12.23
Using low-pressure mercury lamp as light source, combined with the monochromator, the consistency of mercury calibration by mercury permeation tube method and mercury saturated vapor method was studied. In the mercury permeation tube experiment, the Pearson correlation coefficient between the absorption area value and the theoretical concentration was 0.9968, and the goodness of fit was 0.9936, indicating that the two groups of data were well correlated and in accordance with Lamberbeers law. Taking the absorption cross section of the experiment as the standard reference absorption cross section, it was found that the maximum concentration error was 7.45% for horizontal comparison of mercury vapor with the same concentration and vertical comparison of mercury vapor with different concentration. The above results showed that the permeation tube method is feasible, stable and accurate. When SO2 was added to the permeation tube experiment, the maximum measurement error of gaseous mercury concentration was 12.82%, indicating that SO2 interfered with the measurement of mercury absorption degree to a certain extent. In the experiment of mercury saturated vapor method, the maximum error measured with the permeation tube as the reference was within the allowable error of the standard, indicating that the two calibration methods were consistent. However, compared with the permeation tube method, the repeatability and accuracy of the mercury saturated vapor method were still insufficient, and there was a large room for improvement.
2022 Vol. 43 (12): 1663-1668 [Abstract] ( 133 ) HTML (1 KB)  PDF (1687 KB)  ( 174 )
1669 Research on a New Automatic Calibration Device and Calibration Method for Online Water Quality TOC Monitor
HE Fei-fei,DING Bin,CHEN Zi-wang,QIANG Xue-dong,LIU Wei-wei,LI Jing-song
DOI: 10.3969/j.issn.1000-1158.2022.12.24
In order to meet the needs of in-situ calibration of online TOC analyzer used in water quality monitoring in pharmaceutical enterprises under 500μg/L concentration, a set of on-line total organic carbon (TOC) monitor in-situ calibration device is established, which is composed of high-precision micro ceramic injection pump, magnetic mixing unit and constant current syringe controlled by step motor. The high concentration TOC standard stock solution and pure water are proportioned by high precision micro ceramic injection pump and large capacity injection pump controlled by PLC. The automatic calibration of the measuring range below 500μg/L of the on-line total organic carbon (TOC) monitor is realized, with a linear correlation of 0.9924.
2022 Vol. 43 (12): 1669-1676 [Abstract] ( 198 ) HTML (1 KB)  PDF (1934 KB)  ( 294 )
1677 Study on the Influence of Mixed Size Particle on the Evaluation Result of Cutter
LIU Jia-qi,ZHANG Guo-cheng,WU Dan, YANG Zhen-qi,TIAN Ying,JING Wen-jie,HUO Sheng-wei,SHEN Shang-yi
DOI: 10.3969/j.issn.1000-1158.2022.12.25
The performance evaluation of the cutter can be carried out according to the national standards, but the measurement of capture efficiency using 8 kinds of monodisperse particles with particle sizes is time-consuming and the process is complicated. To solve the aboved problem, the influence of mixed particle size on the evaluation of the cutter was studied. By mixing and atomizing the monodisperse particles with different particle sizes, the efficiency of the cutter under several particle sizes could be obtained at one time. By applying the mentioned method and the traditional method to the evaluation of domestic and imported cutters, and comparing the evaluation results, it can be seen that Da50 and the geometric standard deviation δg have good consistency, with the deviation not exceeding 3%, and the measurement time of the mentioned method is 80% shorter than that of the traditional method. The results of the study provide a reference for optimizing the evaluation process of cutter.
2022 Vol. 43 (12): 1677-1682 [Abstract] ( 178 ) HTML (1 KB)  PDF (1774 KB)  ( 101 )
1683 Estimates and Its Corresponding Uncertainty Evaluation of Parameters for Regression Model in Metrology
BAI Jie,HU Hong-bo
DOI: 10.3969/j.issn.1000-1158.2022.12.26
Aiming at the data regression processing method widely used in the field of measurement, the process of least square method and Bayesian inference method used for regression model parameter estimation and corresponding uncertainty evaluation under the condition of normal distribution noise is described. The GUM series uncertainty evaluation criteria do not clearly indicate how to evaluate the uncertainty of regression parameters, and some regression models cannot be uniquely transformed into corresponding measurement equations. Through an example of metrological calibration, how to deal with the determination of the corresponding parameters is illustrated, so as to illustrate the similarities and differences between the two methods. The least square method is simple, direct and easy to use; Bayesian inference based methods can make full use of experience and historical data in metrological calibration. However, since the posterior distribution calculation of parameters is usually complex, Markov Chain Monte Carlo (MCMC) method is required to obtain the results of the concerned parameters through numerical calculation.
2022 Vol. 43 (12): 1683-1688 [Abstract] ( 201 ) HTML (1 KB)  PDF (1738 KB)  ( 239 )
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