Office Online  
    Office Online
    Manuscript Tracking
    Editor Work
    Office Work
    Editor-in-chief
Journal Online
    Current Issue
    Advanced Search
    Archive
    Read Articles
    Download Articles
    Email Alert
Traffic
Quick Search  
  Adv Search
2019 Vol. 40, No. 1
Published: 2019-01-22
 
1 Optimization of acoustic waveguides for acoustic gas thermometry
CHEN Hou-hua,FENG Xiao-juan,LIN Hong,ZHANG Jin-tao,REN Cheng,WANG Ke-jian
DOI: 10.3969/j.issn.1000-1158.2019.01.01
The measurement of the thermodynamic temperature with acoustic gas thermometry from 600 K to 1358 K is a promising research direction suggested by the international temperature metrology community. However, traditional acoustic transducers cannot operate at temperatures higher than 400 K, and the solution is to use high temperature alloy acoustic waveguides to transfer the sound from room temperature to high temperature. The design of the acoustic waveguides is key to the signal-to-noise ratio of the acoustic resonances. Acoustic waveguides with larger inner diameter and shorter length are good for the signal transfer, but it will cause larger perturbation to the acoustic resonator. A new kind of acoustic waveguides with variable dimensions to reduce energy loss along the waveguides as well as the perturbation from the ducts was proposed, and a model of the energy loss and the perturbation for the new design was developde, compared the sound attenuation and the perturbation to the acoustic resonance frequencies and half-widths for different dimensions of the waveguides. The optimized design of the acoustic waveguides can reduce the perturbation to the acoustic resonance frequency to below 3×10-5 for the first longitudinal non-degenerate mode of a cylindrical resonator with an inner length of 80 mm. This research contributes to the further study of high-temperature acoustic gas thermometry.
2019 Vol. 40 (1): 1-7 [Abstract] ( 488 ) HTML (1 KB)  PDF (1285 KB)  ( 441 )
8 The Development and Evaluation of the Co-C Eutectic Point
MENG Su,CAI Jing,DONG Lei
DOI: 10.3969/j.issn.1000-1158.2019.01.02
According to the CCT-WG5s requirement of Co-C eutectic fixed point to all measurement institutions, a filling system was designed and built, using the direct eutectic filling method filled Co-C cells, all cells met the requirement of realizing the Co-C eutectic fixed point. An improvement program was put forward which aimed at solving the disadvantages of direct filling method: low filling efficiency and high probability of crucible breaking, and two Co-C eutectic fixed points were filled successfully. The result of realizing the Co-C-2# eutectic fixed point is that the uncertainty of ascertaining the inflection point temperature was 5.3 mK, which CCTs requirement is less than 10 mK; the short-term repeatability was 9.6 mK, which CCTs requirement is less than 20 mK.
2019 Vol. 40 (1): 8-12 [Abstract] ( 462 ) HTML (1 KB)  PDF (985 KB)  ( 434 )
13 Research of 100~400 K Vacuum Infrared Radiance Temperature Standard Blackbody Source
SHU Xin,HAO Xiao-peng,SONG Jian,YUAN Zun-dong,XUE Sheng-Hu,HU Chao-yun
DOI: 10.3969/j.issn.1000-1158.2019.01.03
The working principles, structure, performance-testing methods and the testing results of the vacuum infrared radiance temperature standard blackbody source is described. By applying liquid nitrogen cooling and 3-temperature-zones controlling, the temperature of this blackbody radiation source can be controlled at the range from 100K to 400K. The axial temperature uniformity, temperature stability of the cavity bottom of the blackbody within 100 ~ 400K are tested in a vacuum environment. Testing results are shown that the uniformity is better than 0.120K, and the stability of the temperature is controlled below 0.020K/20 min, respectively. In the atmospheric environment at room temperature, the emissivity of the blackbody is 0.9998 measured by the method based on controlling surroundings radiation. Based on the Monte Carlo blackbody emissivity simulation method, the influence of the temperature uniformity of the cavity emissivity is analyzed. The source of uncertainty of this blackbody radiation source is analyzed, and the combined standard uncertainty is less than 0.030K when the wavelength is between 8 μm to 16 μm.
2019 Vol. 40 (1): 13-19 [Abstract] ( 439 ) HTML (1 KB)  PDF (1176 KB)  ( 664 )
20 Development and Evaluation of Digital Meter for an Infrared Radiation Thermometer
SHENG Shan-ju,LU Xiao-feng,TANG Xiao-jie,HUAN Ke-wei,WANG Xue-lian
DOI: 10.3969/j.issn.1000-1158.2019.01.04
The IR-RST standard radiation thermometers manufactured by CHINO Company, Limited, Japan, which can not display the temperature in real-time because the display unit hadn’t been designed. Therefore, an electrical measurement display device was designed which can measure the voltage, display the temperature and supply 24V DC voltage for this kind of infrared radiation thermometer. Calibrated a against high-level voltage power source and a voltmeter, the correction coefficients of the display instrument were got, the stabilitywas evaluated as well, the maximum relative error of voltage measurement can be achieved with in 0.03%. Assembled with a 0.65μm IR-RST radiation thermometer, it was calibrated against with a TG HT-9500 type high-temperature furnace as the source, the accuracy was better than 0.03% confirmed by the experimental results, and the extended uncertainty of the calibration system was 0.62℃ at 1 300℃.
2019 Vol. 40 (1): 20-24 [Abstract] ( 439 ) HTML (1 KB)  PDF (1157 KB)  ( 452 )
25 Asphalt Infrared Image Enhancement of Combining Contourlet Transform with Genetic Algorithm
ZHU Dan-dan,WANG Bin,YANG Yi,LI Yong-bo
DOI: 10.3969/j.issn.1000-1158.2019.01.05
As the construction process of asphalt, the collected infrared images are susceptible to the ambient noise, making the image blurred and the SNR low, which leads to decrease the accuracy of the subsequent image processing analysis. Basing on the noise characteristic, a method of combining contourlet transform with genetic algorithm of infrared image enhancement are proposed. Firstly, the original infrared image is subjected to contourlet transform, and the bandpass subband with the multi-scale and multi-directional information is obtained. Then, the bandpass subband carries on the fuzzy enhancement.The fuzzy enhancement parameters are optimized by adaptive genetic algorithm. Finally, the contourlet inverse transform is used in the enhanced bandpass subband, obtain the enhanced infrared image. The experimental results show that compared with other commonly used infrared image enhancement methods, this method can effectively suppress the noise, improve the clarity, and achieve a better enhancement effect.
2019 Vol. 40 (1): 25-30 [Abstract] ( 423 ) HTML (1 KB)  PDF (1292 KB)  ( 332 )
31 Piecewise Sampling and Measurement of Staircase Waveform
LU Zu-liang,YANG Yan,HUANG Lu,WANG Lei
DOI: 10.3969/j.issn.1000-1158.2019.01.06
Staircase waveform is a bridge from DC to AC measurement, and will be a potential bridge from static to dynamic state. A concept of piecewise sampling is proposed. Under this concept the characteristics of staircase waveform is analyzed. The measurement approach for the staircase waveform is discussed with the experiments to overcome the impact from the transient effect and the Gibbs phenomenon. For a typical analogue-to-digital converter with antialiasing filter the selection of the parameters of piecewise sampling is presented for the precise measurement. The experimental results indicate that the impact from fluctuation of samples values to the fundamental amplitude and the root mean square is greatly reduced by the piecewise sampling.
2019 Vol. 40 (1): 31-39 [Abstract] ( 450 ) HTML (1 KB)  PDF (863 KB)  ( 466 )
40 Online Estimation of SOC for Li-ion Battery Based on An Improved Unscented Kalman Filters Approach
CHEN Ze-wang,YANG Li-wen,ZHAO Xiao-bing,WANG You-ren
DOI: 10.3969/j.issn.1000-1158.2019.01.07
An improved unscented Kalman filter (IUKF) approach was proposed to enhance the accuracy and robustness of state of charge (SOC) online estimation, aimed at improving the drawbacks of unscented Kalman filter (UKF) which needs an accurate model and a priori noise statistics. Firstly, Li-ion battery modeling and offline parameters identification were realized. Secondly, sensitivity analysis experiment of the cell’s electrical model was designed to verify which model parameter has the most important influence on the SOC estimation accuracy, and provide the appropriate parameter for the model adaptive algorithm. Thirdly, IUKF approach composed of model adaptive algorithm and noise adaptive algorithm was introduced. Finally, this method was verified through physical experiment. The experimental results revealed that the proposed approach’s estimation error is less than 1.79% with acceptable robustness.
2019 Vol. 40 (1): 40-48 [Abstract] ( 407 ) HTML (1 KB)  PDF (1858 KB)  ( 1195 )
49 Power Quality Disturbance Identification Based on CEEMD and GG Clustering
ZHANG Shu-qing,QIAO Yong-jing,JIANG An-qi,ZHANG Li-guo,JIN Mei,YAO Jia-chen,MU Yong
DOI: 10.3969/j.issn.1000-1158.2019.01.08
A method of power quality disturbance identification based on CEEMD and GG clustering is proposed. CEEMD is a kind of CEMD improved algorithm, its characteristic is putting positive and negative pairs of white noise into the original signal, helps to reduce the residual noise in the auxiliary signal reconstruction; and adding special noise in every stage of decomposition, calculating a unique residual to get each IMF, the decomposition result is complete. Superior to EEMD, CEEMD not only effectively solve the problem of EMD mode mixing, but also retains the advantages of EMD processing non-stationary signals. The CEEMD decomposition of the IMF component of the cross approximate entropy as feature vector is inputted into the GG fuzzy classifier to classify the electric disturbance, The simulational experimental results show that this method has better spectrum separation effect, and needs less iteration times, reduce the computational cost.
2019 Vol. 40 (1): 49-57 [Abstract] ( 374 ) HTML (1 KB)  PDF (3888 KB)  ( 430 )
58 Commutation Ripple Torque and Suppression Method forPermanent Magnet Brushless DC Motor
XIAO Yao-jian,FENG Hao,YANG Han-ying,ZHAO Hao
DOI: 10.3969/j.issn.1000-1158.2019.01.09
Through analyzing the commutation process of the permanent magnet brushless dc motor, the expression of pulsating torque that generated by motor winding current commutation is obtained. In order to verify the correctness of theoretical analysis, the pulsating torque and related characteristics are simulated, then the pulsation torque on shaft was measured with the permanent magnetic rotation angular acceleration sensor, the objective existence of pulsating torque in output torque and related features are verified. For pulsating torque, a torque ripple suppression method based on peak and valley complementary was proposed, and the corresponding experimental platform was set up, the theoretical analysis and experimental measurement obtained the consistent results, so the correctness of the proposed suppression method is verified.
2019 Vol. 40 (1): 58-63 [Abstract] ( 406 ) HTML (1 KB)  PDF (1308 KB)  ( 566 )
64 Self-calibration Algorithm for Laser Multilateral Coordinate Measurement System Using Standard Length Method
ZHENG Ji-hui,MIAO Dong-jing,LI Jian-shuang,XU Zhi-ling, HE Ming-zhao,LI Lian-fu
DOI: 10.3969/j.issn.1000-1158.2019.01.10
The coordinate measuring system based on laser multilateral tracking method has remarkable superiority in the large scale measurement filed,and the accurate calibration of system parameters is the key to achieve high-precision coordinate measurement.To overcome the shortcomings of the traditional calibration method,an improved self-calibration algorithm by using standard length is proposed. Firstly,a number of fixed points are set in the stable base,and the accurately standard lengths along X,Y,Z directions are measured using laser interference method respectively.Then the standard lengths are used to constructed self-calibration optimization functions.By increasing the weight of the corresponding optimization function, the coordinates measurement accuracy is improved further.The feasibility of the algorithm is verified through simulation experiments.Also,the actual experiments are conducted to verify the measurement accuracy of the developed system in large scale range.By comparing with independent laser interferometer measurement results, the error of two groups are distributed in the［-9.5 μm, 4.6 μm］ range as the distances between the compared points to the origin of the coordinate measure system are distributed in the［7.0 m,8.3 m］ interval. The results show that the measurement accuracy of large scale coordinate significantly is improved by the proposed self-calibration algorithm.
2019 Vol. 40 (1): 64-70 [Abstract] ( 479 ) HTML (1 KB)  PDF (1120 KB)  ( 715 )
71 Modeling and Compensation of Thermal Deformation Error of Articulated Arm Coordinate Measuring Machine
LUO Zai,LIU Hui,CUI Xue-wei,LI Dong,TIAN Kun
DOI: 10.3969/j.issn.1000-1158.2019.01.11
The kinematic equation of the thermal deformation error of the AACMM is established. The temperature variation and the measurement error variation trend of the main structural parameters of the AACMM are studied at the experimental temperature of about 20 ℃. A thermal deformation error compensation model based on multiple linear regression method is established and validated. The results show that the AACMM operating temperature rise up to 3℃, measurement error increases with temperature tends to increase, the maximum length measurement error of up to 0.115 mm. And the thermal deformation error compensation of AACMM is realized, the average length measurement error decreased from 0.0715 mm to 0.033 5 mm. The measurement accuracy of the AACMM is improved to a certain extent.
2019 Vol. 40 (1): 71-77 [Abstract] ( 422 ) HTML (1 KB)  PDF (1807 KB)  ( 396 )
78 Study on Antireflective Layer above Superconducting Nb Films
ZHONG Qing,LIU Wen-de,MA Xiao-huan,WANG Jun,ZHENG Chun-di,WANG Xue-shen,LI Jin-jin
DOI: 10.3969/j.issn.1000-1158.2019.01.12
An antireflective layer should be fabricated on the surface of Nb film which was used as the photon energy detection unit in the single photon standard.The spectral refractive index characteristics of Nb films with different thickness made by a magnetron sputter system, SiO2 and SiNx films made by a plasma enhanced chemical vapor deposition system were studied.To reduce the reflection ratio of the superconducting Nb film at 633 nm, the structure of the SiO2/Nb and SiNx/Nb structure were designed and fabricated.The reflectivity was effectively reduced,which was verified by the results of the calculation.
2019 Vol. 40 (1): 78-81 [Abstract] ( 448 ) HTML (1 KB)  PDF (828 KB)  ( 578 )
82 A New Vehicle Licence Plate Recognition Method Based on MSER and SWT
WANG Yan,XIE Guang-su,SHEN Xiao-yu
DOI: 10.3969/j.issn.1000-1158.2019.01.13
In order to reduce the influence of camera distance and the light on license plate recognition, improving the recognition accuracy of license plate with complex background, a new license plate recognition method based on maximally stable extremal regions (MSER)and stroke width transform(SWT) has been proposed. Firstly, the MSER extraction and Canny edge detection are carried out and the filter of the MSER based on geometric features of license plate character is conducted, then the SWT and SW selection of the selected areas is conducted based on morphological processing, the selected regions are gathered and the license plate is located combined with their features. Finally, the segmentation of the location region is checked and its skeleton are extracted and normalized, then, it is matched with the thinned and normalized template. The first character Chinese characters are recognized by HU invariant moments and grid features, and the digits and letters are identified by scanning skip point statistics code. Experiment results show that the accuracy of the location is as high as 94.86% and the accuracyof the recognition is as high as 96.92%, which indicates that this method has high accuracy and robustness for license plate detection and recognition in complex background with long distance and variable illumination.
2019 Vol. 40 (1): 82-90 [Abstract] ( 480 ) HTML (1 KB)  PDF (2039 KB)  ( 533 )
91 Research on Yarn Color Measurement Based on Feedback Multi-spectral Imaging
KONG Xiang-wei
DOI: 10.3969/j.issn.1000-1158.2019.01.14
In order to improve the effect of yarn color measurement,the feedback multi-spectral imaging method is proposed. Firstly, eight channel multi-spectral imaging system was established,and narrowband filter was constituted eight different wavelength. Secondly,threshold of yarn and background segmentation was chosen, yarn target information was obtained to increase the proportion of optimal segmentation threshold. Finally, feedback nonlinear was used to solve spectral reflectance. Experimental simulation shows that the feedback multi-spectral imaging method are better than other methods about CIEDE2000 color difference and root mean square error.
2019 Vol. 40 (1): 91-96 [Abstract] ( 363 ) HTML (1 KB)  PDF (2363 KB)  ( 313 )
97 Temperature Correction of Spectral Radiometer in Calibration System of Optical Radiation Aging Test Chamber
LI Xiang-zhao,HUANG Zhi-fan,DAI Cai-hong,WANG Yan-fei,CHEN Bin-hua,WU Zhi-feng
DOI: 10.3969/j.issn.1000-1158.2019.01.15
As to the influence on spectral radiometer responsiveness from the calibration system temperature of radiation aging test chamber, a temperature correction method of multi order Taylor polynomial fitting for spectral radiometer is developed. After correct the temperature effects of spectral radiometer in calibration system, the deviation of spectral response is less than 2% over the temperature range from 0 ℃ to 55 ℃.
2019 Vol. 40 (1): 97-99 [Abstract] ( 396 ) HTML (1 KB)  PDF (780 KB)  ( 403 )
100 Fault Diagnosis of Rolling Bearing Based on Correlation Dimension and Segment Clustering
MENG Zong,XING Ting-ting,ZHANG Yuan-yuan,ZHOU Ming-jun,YIN Na
DOI: 10.3969/j.issn.1000-1158.2019.01.16
A new fault feature extraction method for rolling bearing based on correlation dimension is proposed. Linear object recognition region is an important factor for the accuracy of correlation dimension, this method is characterized by the fluctuation of the two order derivative corresponding to the linear scaling region of the correlation dimension,the two order derivative data points are transformed into line segments,then the two clustering analysis is done by line segment clustering method, and the gross error is eliminated by statistical rule.Finally, the eigenvalues are fitted to data.This method is used to simulate and analyze the classical Lorenz chaotic system, and the effect is good. Four kinds of signal of rolling bearing are identified, and the experiment shows that the new method can identify the bearing fault signal more accurately.
2019 Vol. 40 (1): 100-105 [Abstract] ( 460 ) HTML (1 KB)  PDF (1686 KB)  ( 473 )
106 Design of Speed Measurement System for Rotating Ammunition
YANG Wen-qing,LI Jie,LI Wen-hao
DOI: 10.3969/j.issn.1000-1158.2019.01.17
Aiming at the problem that the traditional micro-electro-mechanical system gyroscope can not meet the test requirement of the range and accuracy at the same time, a new speed measurement method is proposed by adding a platform to isolate the high-speed rotation of the missile. The system measurement principle and construction are introduced, and the hardware and software design of the system is completed. The effectiveness of system is validated by high precision flight simulation turntable experiment. The measurement system can accurately measure the rotating speed of the missile, the error is about 1°/s, which realizes the purpose of measuring the high rotational speed by the high precision and small range gyroscope.
2019 Vol. 40 (1): 106-110 [Abstract] ( 424 ) HTML (1 KB)  PDF (630 KB)  ( 371 )
111 Online Cold Rolling Prediction Based on Improved OS-ELM
WEI Li-xin,ZHANG Yu,SUN Hao,WEI Xin-yu
DOI: 10.3969/j.issn.1000-1158.2019.01.18
The cold rolling force prediction results directly affect the rolling precision and product quality of the plate (belt). Because of the complicated cold rolling process and strong coupling of parameters, the model is not easy to be established and the actual deviation is large. An improved on-line prediction method of online sequential extreme learning machine is proposed. Using quantum behaved particle swarm optimization algorithm to optimize the weights and thresholds, according to the contribution of the hidden layer to the network output in the current training data, the topology structure of the network is adjusted and realized the self-organization of the structure and parameters. The experimental results show that the self-organizing online sequential extreme learning machine has a higher improvement in the training speed and precision than the artificial bee colony optimization in the reverse propagation neural network and incremental extreme learning machine based on the enhanced random search.
2019 Vol. 40 (1): 111-116 [Abstract] ( 374 ) HTML (1 KB)  PDF (1173 KB)  ( 691 )
117 Methods and Development Trend of Light Pressure Measurement
SONG Le,WANG Yu-jin,ZHENG Ye-long
DOI: 10.3969/j.issn.1000-1158.2019.01.19
To introduce the concept and application of light pressure, according to the media of measuring light pressure, five respective kinds of sensing media which are torsion scales, crystals, films, capacitors and liquids are selected. On the basis of media from macro to microscopic, the stiffness of system from high to low, the measurement principle and development status of each method are introduced and their characteristics are analyzed. Combined with the recent development in the international measurement, the current problems of light pressure measurement are proposed and the prospects of it have been analyzed.
2019 Vol. 40 (1): 117-123 [Abstract] ( 536 ) HTML (1 KB)  PDF (705 KB)  ( 866 )
124 Study on Internal Flow Field and Measurement Performance of Momentum Gas Flowmeter
LIU Zheng-gang,DU Guang-sheng,LIU Li-ping
DOI: 10.3969/j.issn.1000-1158.2019.01.20
The numerical simulation and experiments are used to research internal flow characteristics of momentum gas flowmeter. The changing characteristic of drag coefficient for force-summing element is obtained, the influence of the structure and installation of force-summing element on the measurement performance are studied. The research results show the drag coefficient of momentum gas flowmeter changes greatly and the relationship between drag coefficient and Reynolds should be fitted, the rectangular force-summing element should be selected first because the fitting formula of drag coefficient for rectangular force-summing element has the least error. The maximum error between fitting formula and experimental data is 0.32%. Research results also show the installation error of force-summing element is no more than 0.32% and has little influence on the measurement accuracy and the momentum flowmeter is suitable for on-line installation.
2019 Vol. 40 (1): 124-129 [Abstract] ( 383 ) HTML (1 KB)  PDF (873 KB)  ( 511 )
130 Three-dimensional Combined-electrode Exciting-measuring Mode for Electrical Capacitance Tomography
ZHANG Li-feng,ZHU Yan-feng,SONG Ya-jie
DOI: 10.3969/j.issn.1000-1158.2019.01.21
For the three-layer capacitance array sensor, two kinds of combined-electrode exciting-measuring mode are studied based on three-dimensional simulation. The values and the dynamic range of measured capacitance data, the uniformity of sensitivity distribution and the reconstructed images of different flow regimes are compared with conventional single-electrode exciting-measuring mode. Simulation experiments are carried out using COMSOL and Matlab software. The simulation results show that the measured capacitance values are larger and its dynamic range is smaller for the presented combined-electrode exciting-measuring mode. Meanwhile, the sensitivity distribution is more uniform and the quality of reconstructed images is improved obviously.
2019 Vol. 40 (1): 130-133 [Abstract] ( 378 ) HTML (1 KB)  PDF (915 KB)  ( 393 )
134 A New Algorithm of Wavelet Packet Multi Threshold Speech Denoising Based on Fuzzy Control
CHEN Zhao-quan,ZHU Ming-xing,ZHANG Xiao-bing,ZHANG Tao
DOI: 10.3969/j.issn.1000-1158.2019.01.22
Based on the analysis of wavelet packet traditional threshold denoising algorithm, a new algorithm of wavelet packet multi-threshold speech denoising based on fuzzy control is proposed. The algorithm adopted an improved multi threshold selection method instead of the traditional threshold selection; applied a new threshold function to quantize the bottom frequency coefficients after wavelet packet transform to ensure that the noise signal can be completely filtered out; fuzzy controller can be used to signal amplitude jump and edge roughness and other issues to optimize and correct. By combining these three methods, the speech enhancement process can be carried out adaptively. The experimental results show that compared with the traditional threshold algorithm, this algorithm restore the pure speech information to the greatest extent,effectively improve the accuracy of speech denoising and the signal-to-noise ratio.
2019 Vol. 40 (1): 134-139 [Abstract] ( 367 ) HTML (1 KB)  PDF (1146 KB)  ( 337 )
140 A Novel on Site Calibration Method by Using Double Stimulations
LIANG Zhi-guo,Lü Guo-yi,YIN Xiao,SUN Hao-lin,ZHANG Da-zhi
DOI: 10.3969/j.issn.1000-1158.2019.01.23
Aiming at the difficult of calibrators of non-electric value for in field calibration, the double stimulating method is presented. The data acquisition system connected to transducers is calibrated by using the electric value calibrator. Through the single value stimulating in field as common inputs, both the transducers and the data acquisition are calibrated by using measurement standard in field, and whether or not the transducers are correct can be judged. When correct, the transducers stable transfer function can be represented by using model movement. The model parameters are gotten from calibration in laboratory. Then the whole measurement system can be calibrated in field by using the double stimulating method. From the 6 years duration calibration results of temperature, both the correctness and feasibility method is proved.
2019 Vol. 40 (1): 140-145 [Abstract] ( 384 ) HTML (1 KB)  PDF (1260 KB)  ( 380 )
146 Dynamic Soft Measurement Modeling Method of T-LSSVR in Systems with Time Delay
ZHAO Yan-tao,SHAN Ze-yu,LONG Hai-feng,LIU He-peng,HAO Xiao-chen
DOI: 10.3969/j.issn.1000-1158.2019.01.24
For the delay problem in industrial process system, which lead to not soft sensor modeling in real-time or the lower accuracy of measurement, a modeling method for dynamic soft measurement based on a new algorithm (T-LSSVR) which combines the system delay (T) and least squares support vector regression (LSSVR) was presented.In order to achieve the best estimate of the auxiliary variables, the “static response delay” and “dynamic response delay” can be identified by cross-correlation function and the first order difference algorithm during modeling to the leading variables by the means of soft measurement to predict variables in the method.The soft measurement model was applied to a system with such double-delayed nature of a chemical company and the results show that its prediction achieved good results in terms of both dynamic and steady-state data.
2019 Vol. 40 (1): 146-152 [Abstract] ( 395 ) HTML (1 KB)  PDF (1630 KB)  ( 530 )
153 Study of Gas Pressure Dependence in the Multi-wire Proportional Counter on the Absolute Measurement for Alpha and Beta Sources Surface Emission Rates
LI Yu-qi, WANG Ren-sheng, ZHANG Ming, ZHANG Jun-wei, YANG Zhi-jie, LIANG Jun-cheng
DOI: 10.3969/j.issn.1000-1158.2019.01.25
In order to the investigation of the absolute measurements for α and β surface emission rates due to the working gas pressure variations in China NIM by using α and β multi-wire proportional counter. The surface emission rates measurement of plane sources 241Am、204Tl and 90Sr/90Y is measured respectively by changing working gas pressure in multi-wire proportional counter. The counting rate loss of small pules is corrected by the threshold extrapolation method. The results show that by taking in to account the counting loss of small pules, there is no significant difference observed and all of the measured emission rates are consistent in the range of the evaluated uncertainty within the range of 50 kPa to 180 kPa atmosphere. Monte Carlo simulations based on Geant4 code were also carried out to support our results. The results obtained by the Monte Carlo method are in agreement with the experimental results.
2019 Vol. 40 (1): 153-158 [Abstract] ( 407 ) HTML (1 KB)  PDF (1211 KB)  ( 548 )
159 Preparation of National Primary Reference Materials for PM2.5 Monitors
ZHANG Wen-ge,LIU Wei,XU Xiao,CHEN Zhong-hui,LIU Jun-jie,CHI Shun-xin,HU Xiang-jun
DOI: 10.3969/j.issn.1000-1158.2019.01.26
The preparation method of the national primary reference materials(GBW13642~GBW13649) used in the detection of PM2.5 monitors is introduced. Monodisperse crosslinked polystyrene microspheres with good sphericity were used as candidates of reference materials. The specific values of primary materials were determined by the method which can be traced back to the national standard of length (scanning electron microscopy and image analysis method) and the method of density measurement. The aerodynamic diameter was modeled by the method of calculating the equivalent diameter of classical aerosol dynamics. The experimental results show that the standard materials are most applicable for the detection and calibration of the cutting characteristics of PM2.5 monitors, and can be used as the dust source for the detection and calibration of the PM2.5 monitors.
2019 Vol. 40 (1): 159-163 [Abstract] ( 414 ) HTML (1 KB)  PDF (909 KB)  ( 418 )
164 Measurement uncertainty in NOS terminator from genetically modified rice estimated by Monte Carlo Method
SONG Jun,CHANG Li-juan,ZHANG Fu-li,WANG Dong,LI Jie
DOI: 10.3969/j.issn.1000-1158.2019.01.27
Owing to the complex process of GMO testing such as multi-stages with several intermediate inputs/outputs and their joint probability distribution, the propagation of probability distribution was employed here for the first time to evaluate the MU in NOS terminator from genetically modified rice using Monte Carlo Method. The results showed that the relative content of NOS termination was 2.95%, very close to the theoretical content (3%), and the standard uncertainty was 2.13×10-4, which was much less than 1.00×10-2. In the coverage probability 95%, the relative content of NOS terminator is within a very narrow range of 2.91%~3.00%, indicating the measurement quality in this work is very good, and the measurement results are very reliable. Moreover, the relative contents of NOS terminator followed standard normal distribution, revealing the measuring conditions in the testing of GMOs are agreement with the assumption in GUM approach. Consequently, both MCM and GUM method can be applied to evaluation of measurement uncertainty in the detection of GMOs.
2019 Vol. 40 (1): 164-171 [Abstract] ( 378 ) HTML (1 KB)  PDF (534 KB)  ( 297 )
172 Measurement Uncertainty Evaluation Based on Maximum Entropy Interval Analysis
YAO Cheng-qian
DOI: 10.3969/j.issn.1000-1158.2019.01.28
In order to improve the accuracy of measurement uncertainty evaluation, the maximum entropy interval analysis method was proposed. Firstly, the model was established combining maximum entropy algorithm and Bayesian model.Secondly, asymmetry of lower and upper bounds for sample information of input quantity was analysised, and the Jaynes entropy and Lagrange were obtained the shortest interval.Lastly, the input information was divided the sample interval to determine the ratio of the measured uncertainty, considering the input uncertainty with probability distribution of the transfer process.The simulation results show that the algorithm has less range of measurement uncertainty and the result is more accurate.
2019 Vol. 40 (1): 172-176 [Abstract] ( 431 ) HTML (1 KB)  PDF (601 KB)  ( 387 )
News
Download
Links
Copyright © Editorial Board of Acta Metrologica Sinica
Supported by:Beijing Magtech