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2019 Vol. 40, No. 4
Published: 2019-07-22
 
541 The Characteristics of the New SI Base on “second system” and its Future Development
SONG Ming-shun, FANG Xing-hua,MA Ai-wen,WU Zeng-yuan
DOI: 10.3969/j.issn.1000-1158.2019.04.01
The new International System of Units will be introduced on May 20, 2019. The main change is that the seven basic units are derived from one or more defined basic constants, so a perfect standard definition for the basic unit is established. Specifically, the new definitions of kilogram, ampere, kelvin, and mole in current revision of SI are discussed, as well as their characteristics. Then by reviewing the development of SI, a concept of "second system" is proposed to describe the essences of the revised SI. On the basis of the limitations and the problems which may be faced, an advanced SI structure, which is more open and extensive coverage in multidisciplinary quantities, is put forward, furthermore, the corresponding framework of the future SI system is depicted.
2019 Vol. 40 (4): 541-548 [Abstract] ( 411 ) HTML (1 KB)  PDF (2399 KB)  ( 820 )
549 Calibration Method for Depth Measurement of Nano/microstructure in Scanning Probe Microscopy
LIU Jian,GU Kang,LI Meng-zhou,YOU Xiao-yu,LIU Chen-guang,WANG Yu-hang,TAN Jiu-bin
DOI: 10.3969/j.issn.1000-1158.2019.04.02
Scanning probe microscopy (SPM) is an essential technology for three-dimensional measurement of nano/microstructure. However, there are uncertain profiles near step or groove sample edges, which bring about accuracy loss of depth measurement. In order to avoid the accuracy loss of depth measurement, two analytical models for mechanical probes and optical probes were established respectively, the coupling relationships among uncertain profiles, depth of samples, and shape of probes were depicted. Based on the above models, a calibration method for depth measurement with a promising accuracy was proposed. Compared with the existing international standard for depth measurement (W/3 rule), the proposed method provides a clear boundary to determine if the measurement results are valid. Furthermore, it can also guide the user to select the appropriate probe before performing measurements.
2019 Vol. 40 (4): 549-556 [Abstract] ( 416 ) HTML (1 KB)  PDF (3087 KB)  ( 682 )
557 Solution to Wall Thickness of Continuous Casting LadleBased on Laser Positioning and Ranging
LIU Jun,WU Xin-hua,MENG Xian-wu,FANG Jiang-xiong,HOU Qing-ming,ZHAO Peng,YANG Feng
DOI: 10.3969/j.issn.1000-1158.2019.04.03
A method to measure wall thickness of continuous casting ladle based on laser positioning and ranging is proposed. Firstly, positioning lasers are used to detect the spatial coordinates of the measured ladle. Secondly, the inner surface of the ladle is scanned by measuring laser driven by a rotary platform. According to the spatial coordinate transformation, the data of the measured points on the inner surface of the ladle are mapped to the wall thickness of the ladle. Finally, the thickness distribution of the inner wall of the ladle is obtained by comparing wall thickness with the standard initial data of the ladle. After test in the metallurgy filed, it shows that the method can measure the thickness of ladle wall accurately, the maximum measuring error is 5.2 mm, the minimal error is 2.6 mm, and the average error comes to 3.6 mm.
2019 Vol. 40 (4): 557-562 [Abstract] ( 325 ) HTML (1 KB)  PDF (1248 KB)  ( 490 )
563 Statistical Analysis on the Impacts of Excitation Sources on Tilt Sensors Online Calibration
JING Gen-qiang,DUAN Fa-jie,LI Jian-shuang,LUO Zhu
DOI: 10.3969/j.issn.1000-1158.2019.04.04
Sensors are key units of bridge health monitoring (BHM) systems for data collection. However, their measuring performance cannot be easily verified in situ for the absence of proper excitation sources and methods. An online calibrating method is presented which aims at using the load combination by traffic vehicles as an excitation source. To verify the impacts of excitation characteristics on the stability of calibrating results, an experiment is designed with input deflection step length ranging from 0 to 10mm and variation period being 5s, 10s, 15s and 20s. The experiment is performed on a simply supported beam bridge model under random excitation simulated by a programmable linear module. Hypothesis testing is conducted with the experimental results, which shows that given the significance level 0.05, the deflection amplitude and period of excitation source have no effect on calibrating results of the sensors.
2019 Vol. 40 (4): 563-568 [Abstract] ( 308 ) HTML (1 KB)  PDF (1572 KB)  ( 449 )
569 Research on Screening Methods of LED Filament
JIANG Lin,LIU Hui,YAN Jin-yun,ZHAO Wei-qiang,SU Ying
DOI: 10.3969/j.issn.1000-1158.2019.04.05
For a group of commercially obtained LED filaments without screening, the difference of total luminous flux is 7% and the difference of voltage is 0.6% . If the filament is directly used to make standard lamps without screening, it will not achieve the expected luminous intensity spatial distribution, the lamp stability and rated life will be reduced also. A screening method for LED filament has been prosed based on a series experiment, the voltage and luminous flux correlation between low driven current and rated driven current is analyzed. It shows that if 5 mA is used to instead of the rated driven current 10 mA for screening, the maximum deviations of voltage and luminous flux are 0.09% and 0.65%, respectively, which can meet the screening needs. The developed screening method and related software make the screening process fast to operate, accurate and reliable to determine the results, and does not reduce the rated life of the filament. This has laid a good foundation for the development of total luminous flux standard lamp using LED filament, that can also be applied to quality control in the production process of LED filament.
2019 Vol. 40 (4): 569-575 [Abstract] ( 308 ) HTML (1 KB)  PDF (1416 KB)  ( 419 )
576 DCNN for Task Coordination of Facial Landmark Localization and Head Pose Estimation
TIAN Zhuo,SHE Qing-shan,GAN Hai-tao,MENG Ming
DOI: 10.3969/j.issn.1000-1158.2019.04.06
In order to improve the performance of facial information recognition under complex conditions, a novel deep convolutional neural network (DCNN) method is proposed for the task coordination of facial landmark localization and head pose estimation.First, the facial information is detected from video images.Secondly, a DCNN model is designed for synergistic optimization of both facial landmark localization and head pose estimation tasks, and then used to simultaneously estimate the coordinates of facial landmarks and the angles of head pose,which are then fused to generate the human-computer interaction information.Finally, the proposed method is tested on both public datasets and actual scene data, and then compared with other state of the art methods.Experimental results show that the proposed approach performs better in facial landmark localization and pose estimation,and also achieves good accuracy and robustness in the HCI applications under complex conditions of illumination variations, expression changes and partial collusions, with the average speed at 16 frames per second, which demonstrates its efficiency and practicality.
2019 Vol. 40 (4): 576-582 [Abstract] ( 331 ) HTML (1 KB)  PDF (1555 KB)  ( 745 )
583 Image Dehazing Based on Near and Far Scene Dark Channel Prior
TIAN Yuan
DOI: 10.3969/j.issn.1000-1158.2019.04.07
In order to improve the effect of image dehazing, near and far scene dark channel prior, was proposed. Firstly,mixed dark channel prior was established, which is included minimum channel of near scene and dark channel prior of far scene, and set adjustment coefficient of different scene region. Secondly, atmosphere light value was estimated with 50 pixel color average value of mixed dark channel prior far scene, and added correction coefficient.Thirdly,transmission was optimizated with adaptive sliding window of guided filtering.Finally,process was given.Experiment simulation showed that mixed dark channel prior has better visual effect,and contrast ratio and visible edge contrast ratio of quantitative analysis indexes are better than other algorithms.
2019 Vol. 40 (4): 583-588 [Abstract] ( 314 ) HTML (1 KB)  PDF (1835 KB)  ( 328 )
589 Research on Sub-pixel Registration Method Based on Phase Correlation and Signal Sampling
LI Ji-zhe,ZHU Wei-bin,YE Shu-liang
DOI: 10.3969/j.issn.1000-1158.2019.04.08
In order to solve the contradiction of mutual restriction between high spatial resolution and large field of industrial cameras highlighted in the visual measurement of fine-pitch gear, sub-pixel image registration method based on phase correlation is studied. The cause of the phenomenon that main peak and sub peak produced when inverse Fourier transform the cross power spectrum is analyzed. The corresponding relationship between peak amplitude and relative displacement is described finally. The method was applied to image registration of the fine-pitch gear, the result shows that the error was less than 0.002 pixels.The error of this method is analyzed without considering the influence of incoherent regions and the experimental result shows that this method exists non-cumulative error whose period is 1 pixel, the error introduced by function approximation is less than 5×10-8 pixels.
2019 Vol. 40 (4): 589-594 [Abstract] ( 308 ) HTML (1 KB)  PDF (1569 KB)  ( 724 )
595 On - Orbit Calibration of Temperature Sensor based on Miniature Gallium - based alloy Fixed point
WEN Ping, HAO Xiao-peng, SUN Jian-ping, YUAN Zun-dong, DING Lei, CHANG Jia-qiang
DOI: 10.3969/j.issn.1000-1158.2019.04.09
A calibration method of the on-orbit temperature sensor based on the gallium - based alloy miniature fixed point is proposed. The developed process of the Gallium - based alloy miniature fixed points for on-orbit calibration and the quasi-adiabatic vacuum measurement system are introduced. Combined with cavity blackbody and non-proximal mounted temperature sensor, the repeatability of Ga-Sn and Ga-Zn alloy fixed points is measured,which was better than 2mK during melting process. For Ga, the long-term stability is 2.1mK. The temperature sensor at the bottom of cavity blackbody was indexed by the continuous melting plateau value measured by temperature sensor during gallium and two gallium-based alloy fixed points melting process in a specific thermal environment. The difference between the calibration result and the routine calibration method in the laboratory is less than 2mK. The results are also shown as the phase transformation time increases, the phase transition temperature is closer to the melting temperature of the phase change material, ie, the smaller the temperature difference between the fixed point and the temperature sensor hole, in the thermal environment conditions remaining unchanged. Meanwhile, for Ga-Sn and Ga-Zn, there is a linear relationship between the phase transition melting temperature and the single-point calibration temperature at zero power is 20.352°C and 25.187°C.
2019 Vol. 40 (4): 595-602 [Abstract] ( 353 ) HTML (1 KB)  PDF (2116 KB)  ( 558 )
603 Analysis and Simulation of Coal Sampling Uncertainty in Coal-fired Utility Boiler
LIU Fu-guo,CUI Fu-xing
DOI: 10.3969/j.issn.1000-1158.2019.04.10
Aiming at quantitative analysis of uncertainty of coal heat value in process of coal sample collection, actual sampling experiments are carried out in 17 boilers of 6 power plants. Uniformity of coal quality being expressed by variance of concentration, coal sampling random model revised by experiments is established to analyze effects of uniformity of coal quality on uncertainty of coal heat value, on basis of this, the dispersive characteristics of the weighted average calorific value of coal are investigated, and it shows that (1) Uncertainty of coal heat value caused by coal sampling process in different boilers are ranged from 1 ~ 4.82MJ/kg, (2) The worse of coal mixed uniformity, the greater of coal heat value uncertainty in coal sampling process, (3) Coal calorific value uncertainty can be significantly reduced by the weighted average calorific value of coal.
2019 Vol. 40 (4): 603-609 [Abstract] ( 324 ) HTML (1 KB)  PDF (1243 KB)  ( 281 )
610 Parameter Identification and Optimization of the DTS Sensing Model Based on the Nonlinear Genetic Algorithm
TENG Feng-cheng,ZHANG Hao-yang,CHENG An-di,WANG Shan-shan
DOI: 10.3969/j.issn.1000-1158.2019.04.11
Based on fiber Raman scattering efficiency and Monte-Carlo method, a DTS sensing model is established. The nonlinear genetic algorithm is adopted to conduct the parameters identification of DTS sensing model, and the influence of the population size, evolutionary algebra, crossover rate and mutation rate on the operation result of the algorithm are analyzed,and the optimal parameter combination is selected. The experimental platform of distributed optical fiber temperature sensing system is established, and the DTS sensing model is used to conduct the simulation predicted of distributed optical fiber temperature sensing system. The results of the experiment and simulation show that the predictive error of the sensing model is within 0.24% when the spatial resolution is 1 m, and the temperature measurement error of the distributed optical fiber temperature sensing system is no more than 0.40 ℃.
2019 Vol. 40 (4): 610-617 [Abstract] ( 336 ) HTML (1 KB)  PDF (2246 KB)  ( 516 )
618 Weak Signal Measurement in Thermoreflectance Temperature Testing Based on Stochastic Resonance
ZHAI Yu-wei,ZHENG Shi-qi,LIU Yan,LI Ying-hui,LIANG Fa-guo
DOI: 10.3969/j.issn.1000-1158.2019.04.12
A method of using stochastic resonance to improve the temperature resolution of CCD based thermoreflectance was proposed. A specific quantization rule of CCD detector was supposed, the principles of stochastic resonance work on the nonlinearly CCD detector were analyzed, the measurement results by CCD detector after applying stochastic resonance were calculated in theory. A simulation program based on LabVIEW was developed to simulate the effects of kinds of stochastic noise on measuring weak signals, and the simulation results were consistent with the calculation ones. The simulation also showed that the weaker the noise intensity is, the lager the errors is, when the noise intensity was more than 1, the simulation results were nearly equal to the accurate ones. A thermoreflectance apparatus with a theoretical resolution 1.035℃ was installed, a 0.5℃ weak signal was measured, the results were between 0.455~0.673℃, it is confirmed that stochastic resonance can improve the weak signal measurement capability of CCD detector.
2019 Vol. 40 (4): 618-624 [Abstract] ( 330 ) HTML (1 KB)  PDF (1539 KB)  ( 280 )
625 Study on Integrated Emissivity of an Isothermal Blackbody Cavity with Response Surface Methodology
LIU Bo,ZHENG Wei,LI Hai-yang,MA Chao,ZHU Xin-yun
DOI: 10.3969/j.issn.1000-1158.2019.04.13
High-performance blackbody radiation source is the key equipment for highly precision reproduction of radiation temperature. Integrated emissivity of blackbody cavity numerically simulated by finite volume method (FVM) has a good agreement with the result computed by Monte-Carlo method (MCM). Moreover, the FVM can predict the trend of integrated emissivity more accurately than MCM. Based on design of experiment with response surface method, key factors and their interactions of a cylindro-conical cavity, such as length-to-diameter ratio L/D, aperture diameter to cylinder diameter ratio Da/D, cone angle θ, and intrinsic emissivity of the cavity surface ε, are analyzed for integrated emissivity εe. The results show that Da/D and ε are significant factors; L/D and θ have less influence on εe. The results can provide references for the manufacture and study on high-performance blackbody radiation source.
2019 Vol. 40 (4): 625-630 [Abstract] ( 297 ) HTML (1 KB)  PDF (1345 KB)  ( 258 )
631 Image Reconstruction for Electrical Capacitance Tomography Based on Barzilai-Borwein Gradient Projection for Sparse Reconstruction Algorithm
ZHANG Li-feng,SONG Ya-jie
DOI: 10.3969/j.issn.1000-1158.2019.04.14
During the process of image reconstruction for electrical capacitance tomography, the permittivity of sparse distribution flow regime meets the priori condition of sparsity, the ECT image reconstruction algorithm based on Barzilai-Borwein gradient projection for sparse reconstruction (GPSR-BB) was presented to solve the problem that the reconstructed image is poor when there is a central object, the object is small or there are many objects close to each other in the two-phase flow. Simulation and experimental results showed that GPSR-BB algorithm has a better imaging effect for image reconstruction of small and complex flow patterns, and the reconstructed images with better shape fidelity can be obtained.
2019 Vol. 40 (4): 631-635 [Abstract] ( 325 ) HTML (1 KB)  PDF (1022 KB)  ( 603 )
636 Reconstruction Method on Curve of Explosive Shock Wave in the Air
YAO Yue,DING Yong-hong,PEI Dong-xing,ZHANG Xiao-guang
DOI: 10.3969/j.issn.1000-1158.2019.04.15
To reconstruct shock wave overpressure curve effectively, a method on reconstructing the shock wave curve in the air was proposed. Gauss-Newton algorithm was used to get the nonlinear regression curve of the actual shock wave curve, getting the best regression curve from the gradient-direction iterative process of the target parameters and obtaining the actual attenuation coefficient. Establishing a cartesian coordinate system with the explosive source as the origin on the ground, overpressure peak and attenuation coefficient of test point respectively have the polynomial function relationship with test point coordinates. Zippel interpolation algorithm was used to obtain the global optimal solutions of the items' weights in the function, obtaining the overpressure peak and attenuation coefficient of the unknown test points, and reconstructing the shock wave curve. The result showed that the average errors of reconstructed attenuation curves obtained by the method and actual measurement curves is within 17%.
2019 Vol. 40 (4): 636-641 [Abstract] ( 311 ) HTML (1 KB)  PDF (996 KB)  ( 448 )
642 Volumetric Table Fitting Method Based on Interpolation Algorithm and Time Series
MA Xin-yu,WANG Jin-tao,SUN Bin,LIU Xiang,ZHENG He,ZHONG Jia-dong
DOI: 10.3969/j.issn.1000-1158.2019.04.16
On the basis of the measured tank height-volume sampling points, a cubic spline curve interpolation and exponential time series analysis method are used. The values generated by the spline interpolation are used to make up the values in the sampling points of the volumetric table. The time series analysis method is used to calculate the unmeasured values at the tank bottom and the tank top. In the actual measurement test, the maximum deviation of the simulation of the cubic uniform B-spline curve interpolation from the actual value is less than 0.3%. The data measured by the time series analysis method provide the reference value, and the two data are forwardly pushed forward with the actual deviation less than 1%.
2019 Vol. 40 (4): 642-646 [Abstract] ( 306 ) HTML (1 KB)  PDF (447 KB)  ( 482 )
647 Nano-machining AFM Tip Wear Monitoring Based on Time Series Data and Support Vector Machine
CHENG Fei,DONG Jing-yan
DOI: 10.3969/j.issn.1000-1158.2019.04.17
Time-series data analysis and pattern recognition using support vector machine (SVM) are studied to monitor the state changes of the AFM tip-based nanomachining process with respect to the machining performance and tip wear. Time series data (i.e. machining force from the process), which has transient, nonlinear, and non-stationary characteristics, is collected by a data acquisition system. Three status detection features including the maximum force, peak to peak force value, and the variance of the collected lateral machining force, are extracted to classify the state of the nanomachining process. Directed acyclic graph support vector machines with a (Gaussian) radial basis kernel function is constructed to identify the tip wear status. Using this multi-class SVM, the machining process and the tip wear can be classified into three regions, which are effective machining with sharp tip, transition region, and bad/no machining with severe tip wear. The experimental data shows that the accuracy of the SVM is over 94.73% in both binary and ternary classifications.
2019 Vol. 40 (4): 647-654 [Abstract] ( 279 ) HTML (1 KB)  PDF (2147 KB)  ( 304 )
655 Strain Measurements of Shear Bands Based on Least-square Fitting of Local Displacements Based on the Digital Image Correlation Method
WANG Xue-bin,HOU Wen-teng,DONG Wei,YANG Mei,CAO Si-wen
DOI: 10.3969/j.issn.1000-1158.2019.04.18
Strains in the fictitious shear band are measured by use of least-square fitting of local displacements of the digital image correlation method, and strains are compared with those obtained by use of the central difference method and the analytical solution. Effects of the size of the calculating window and the size of the subset are mainly demonstrated. It is found that when the calculating window is larger and the size of the subset is lower, strains are closer to the analytical solution. Strains during the failure process of the low liquid-limit clay specimen under uniaxial compression are measured by use of least-square fitting of local displacements method and the central difference method, and strains are measured by least-square fitting of local displacements method are more accurate, which is helpful for the accurate measurement of strains of shear bands.
2019 Vol. 40 (4): 655-661 [Abstract] ( 320 ) HTML (1 KB)  PDF (3271 KB)  ( 373 )
662 Parameter state analysis of grate cooler based on Bayesian structure algorithm based on classification optimization& and convergence analysis
LIU Hao-ran, SUN Mei-ting, WANG Hai-yu, ZHANG Li-yue, FAN Rui-xing, LIU Bin
DOI: 10.3969/j.issn.1000-1158.2019.04.19
Aiming at the problem that population algorithms of Bayesian structure learning have many parameters and easily fall into local optimum, an improved Bayesian structure learning algorithms is proposed. The algorithm combines the advantage of teaching learning based optimization without parameters and the random search of mutation mechanism. Teaching learning based optimization and mutation mechanism contrapuntally optimize candidate structures to learn the best Bayesian network structure. Teaching learning based optimization optimizes excellent set of structures to preserve entity. Mutation mechanism optimizes poor set of structures to increase structural diversity. By these operations, this algorithm not only accelerates the convergence speed , but also the balance between solutions quality and computational effort. Finally, the convergence of the algorithm is analyzed by Markov chain. The simulation results have shown that these properties can be achieved.
2019 Vol. 40 (4): 662-669 [Abstract] ( 380 ) HTML (1 KB)  PDF (962 KB)  ( 416 )
670 Wheel Model Identification Based on Index Weight Vector of Aggragate Locally Descriptor Features
ZHANG Dian-fan,GUAN Yong-lai,ZHANG Li,CHENG Shu-hong
DOI: 10.3969/j.issn.1000-1158.2019.04.20
In the process of wheel model identification, in order to quickly identify the correct wheel model in a large number of wheel model data base, a identification algorithm based on index weight VLAD(vector of aggragate locally descriptor) is proposed. The VLAD feature is an improved version of the BOW, using the cumulative residuals between features and cluster centers replace the cumulative number of features, as the searching algorithm we use four nearest neighbor soft allocation, and has better robustness than the one to one allocation rule. Then the PCA is used to reduce dimensions of VLAD obtained above, the multiply index weight and the data of descending dimension VLAD to reduce individual instability value, and finally, the most similar pictures are found by comparing the feature vectors. The experimental results shows that this algorithm has the advantages of non-contact, perform well on flexibility and accuracy, it also improves the identification rate and has good robustness.
2019 Vol. 40 (4): 670-675 [Abstract] ( 275 ) HTML (1 KB)  PDF (1123 KB)  ( 259 )
676 Study on Calibration of Low Pressure/Vacuum Comprehensive Environmental Test Equipment Based on Heat Transfer Theory
ZHAO Wen-tao,CHENG Lei,SHEN Hui-feng,CAO Jia-xing,NI Bo
DOI: 10.3969/j.issn.1000-1158.2019.04.21
The referenceable calibration basis for low pressure/vacuum integrated environmental test equipment is not comprehensive at present, the analysis of applicable standard specification for low pressure integrated test equipment of different pressure ranges is given and the guiding conclusions are conducted through a numerical simulation. Numerical simulation results show that the test equipment with internal pressure greater than 1kPa can refer to standard GB/T 5170.10 for the calibration of temperature deviation and temperature uniformity. The tolerance requirement can be appropriately relaxed according to the increase of the working space and the decrease of the internal pressure. Radiation heat transfer occupy a dominant position in test equipment with air pressure less than 1kPa. The heat transfer efficiency is related to the placement of internal test pieces. It is not necessary to consider the temperature uniformity of the equipment. Reducing the space thermal resistance and surface thermal resistance in the measurement are the key to improving the measurement accuracy.
2019 Vol. 40 (4): 676-680 [Abstract] ( 321 ) HTML (1 KB)  PDF (1107 KB)  ( 485 )
681 Adaptive Second-order Underdamped Stochastic Resonance Signal Enhancement Method Based on Periodic Potential Function
CHEN Jian,TAO Shan-yong,WANG Wei,Lü Wu-yang
DOI: 10.3969/j.issn.1000-1158.2019.04.22
Aiming at the problem that the faulty vibration signal of rolling bearing is difficult to extract under noisy environment, an adaptive second-order underdamped stochastic resonance signal enhancement method based on periodic potential function is proposed. The method uses particle swarm optimization to measure system parameters and damping. The adaptive matching of the coefficients realizes the stochastic resonance of multiple pseudo-enhanced frequency bands, and is more suitable for multi-fault signal extraction in engineering practice. The test of fault signal and the engineering experiment show that: 1) The adaptive second-order under-damped stochastic resonance method based on periodic potential function significantly improves the output signal-to-noise ratio, the main peak of the fault characteristic frequency is prominent. The sideband interference is less, the machine is easy to fault, and the false positive rate is low. 2) With the increase of noise intensity, although the output signal-to-noise ratio is reduced, the adaptive second-order underdamped stochastic resonance method based on periodic potential function, the detection effect is still better than the adaptive first-order stochastic resonance method based on periodic potential function. 3) The adaptive second-order under-damped stochastic resonance method based on periodic potential function is more adaptable to noise, in noisy environment, there are obvious advantages for the extraction of weak fault signals.
2019 Vol. 40 (4): 681-685 [Abstract] ( 288 ) HTML (1 KB)  PDF (1385 KB)  ( 750 )
686 Studies on Ultrasonic Power Measurement of Cylindrically Converging Wave based on Self-reciprocity Technique
YU Li-li,SHOU Wen-de
DOI: 10.3969/j.issn.1000-1158.2019.04.23
A self-reciprocity technique is proposed to measure the ultrasonic power for cylindrical converging wave. This study defines the electro-acoustic parameters of cylindrically converging wave,namely,the reciprocity coefficient,transmission current response,and the voltage sensitivity for the free field. Numerical calculations of reflection and diffraction correction coefficients are discussed. Formulas of ultrasonic power for self-reciprocity technique with cylindrical converging wave are derived. Comparison experiments with radiation force balance (RFB) method shows good agreement. Measuring ultrasonic power via the self-reciprocity technique for cylindrical converging waves is found reasonable and feasible.
2019 Vol. 40 (4): 686-692 [Abstract] ( 308 ) HTML (1 KB)  PDF (995 KB)  ( 344 )
693 Estimation of SOC of Li-ion Battery in Pure Electric Vehicle by BSA-RELM
WU Zhong-qiang,SHANG Meng-yao,SHEN Dan-dan,QI Song-qi,ZHU Xiang-dong
DOI: 10.3969/j.issn.1000-1158.2019.04.24
A method based on bird swarm algorithm optimizing robust extreme learning machine is proposed to estimate the charge state of the battery. Robust extreme learning machine overcomes the shortcomings that extreme learning machine can not deal with the abnormal value, so the prediction accuracy of the network is improved. The parameters such as the number of hidden nodes and the adjustment factors of robust extreme learning machine are optimized by bird swarm algorithm, so the problems that the parameters such as the number of hidden nodes and the adjustment factors are difficult to be determined can be solved, which can further improve the convergence speed of the network and help to find the global optimal value. Several key parameters including current, voltage, temperature and internal resistance, which affect the SOC characteristics of the battery, are collected to model and test by ADVISOR software. Simulation results show that compared with other algorithms such as BPNN, RBFNN and FNN, BSA-RELM has a smaller error and higher prediction accuracy.
2019 Vol. 40 (4): 693-699 [Abstract] ( 262 ) HTML (1 KB)  PDF (1451 KB)  ( 294 )
700 Review of the Technologies of the Magnetic Flux Density Base Standard
FU Ji-qing,ZHANG Wei,HE Qing
DOI: 10.3969/j.issn.1000-1158.2019.04.25
To reviews the uncertainty and the application about currently used base standards about magnetic flux density (MFD), which include the artifactitious standard based on calculated coil, the quantum standard based on the principle of nuclear magnetic resonance (NMR), and the fundamental physical constant standard based on gyromagnetic ratio of proton. The field of quantum precise measurement is developing rapidly in recent years, and some new advances are bring out like the atomic magnetic resonance (AMR) quantum standard which can achieve higher accuracy than NMR standards, and the superconducting NMR technology which can expand the lower bound of NMR standards. To particularly reviews the technologies about the current quantum stands of MFD, and briefly introduces some new techniques that expected to expand the new frontiers of magnetic metrology.
2019 Vol. 40 (4): 700-703 [Abstract] ( 371 ) HTML (1 KB)  PDF (479 KB)  ( 586 )
704 The Impact of the Adapters on Impedance Measurement of EMC RF Conducted Coupling-Decoupling Network
ZHAO Pin-zhang
DOI: 10.3969/j.issn.1000-1158.2019.04.26
The coupling-decoupling network (CDN) is widely applied in electromagnetic compatibility (EMC) for conducted radio frequency susceptibility tests. The impedance of equipment under test (EUT) port is the most important parameters in CDN calibration. To measure the impedance, adapters are required to connect the vector network analyzer (VNA) to the EUT port of the CDN. Until now, the impact of the adapters used has not been clearly demonstrated by the domestic calibration laboratories, while the impedance errors at high frequencies are caused by the adapters. Therefore, basing on experimental and theoretically calculating principles, two methods, which are defined as self calibration of VNA after coaxially converting and calculation by electrical length compensation, have been presented. The data indicate that the two methods are valid for removing the adpaters' impact, and the impedance measurement results have be improved.
2019 Vol. 40 (4): 704-707 [Abstract] ( 318 ) HTML (1 KB)  PDF (1170 KB)  ( 341 )
708 Comparative Study on Denoising Methods of EEG Signals Based on Subcomponent Decomposition
FU Rong-rong,BAO Tian-tian,TIAN Yong-sheng,WANG Lin
DOI: 10.3969/j.issn.1000-1158.2019.04.27
EEG signals contain abundant time and spatial information. In order to obtain good real-time and anti-interference physiological signals, a large number of weak EEG signal extraction techniques have been applied. In view of the fact that the actual physiological EEG signals are susceptible to irrelevant noise and other issues, the maximum signal fraction analysis and independent component analysis methods are compared to remove the artifacts contained in the EEG signals and the real-time performance of the processing. The effect of the solution is evaluated from the three aspects of scatter plot analysis, correlation index comparison and calculation speed. The results show that both methods have the effect of separating noise signals and can guarantee the real-time performance. However, maximum signal fraction analysis has better separation effect than independent component analysis, higher correlation index, higher similarity, similarity value floating smaller advantages of a more stable, and has a wider range of application prospects.
2019 Vol. 40 (4): 708-713 [Abstract] ( 339 ) HTML (1 KB)  PDF (1368 KB)  ( 848 )
714 Modeling and Analysis of Prediction Uncertainty of Clock Difference in Atomic Clock
ZHU Jiang-miao,CHEN Ye,GAO Yuan,YAN Di,WANG Xing
DOI: 10.3969/j.issn.1000-1158.2019.04.28
Atomic clock difference prediction is the key step in atomic clock time scale generation and atomic clock control. The atomic clock is a precise signal source, and its signal consists of the determined signal part which is corrected by the prediction algorithm and the inherent noise, which is a random part. The hydrogen and cesium clock mainly contain two kinds of noise, that is, white frequency noise and random walk frequency noise. These two kinds of noise are the main factors that produce the uncertainty of prediction. The mathematical expression of the prediction uncertainty of the time difference data of the atomic clock is derived, based on the mathematical model of the atomic clock, and the minimum prediction uncertainty of the clock group is obtained. The influence of the number of clocks in the clock group on the prediction uncertainty is analyzed. Finally, the correctness of the theory is verified.
2019 Vol. 40 (4): 714-720 [Abstract] ( 286 ) HTML (1 KB)  PDF (1000 KB)  ( 341 )
721 Biological Water Quality Monitoring Method Based on Convolution Neural Network
CHENG Shu-hong,ZHANG Shi-jun,ZHAO Kao-peng
DOI: 10.3969/j.issn.1000-1158.2019.04.29
Biological water quality monitoring is usually through the extraction of water stress response characteristics in different environments, and then feature classification, so as to identify water quality. Aiming at the problem of water quality monitoring, method of CNN convolution neural network was presented. Fish trajectory is a comprehensive expression of the various water quality classification characteristics used in all the literatures and is an important basis for the classification of biological water quality. Using the image segmentation method of Mask-RCNN to obtain the centroid coordinates of the fish and draw the trajectory image of the fish in a certain period of time. Two sets of trajectory image data sets under normal and abnormal water quality were produced. The Inception-v3 network serves as a feature preprocessing part of the data set, the CNN convolution neural network was reestablished to classify the features extracted by Inception-v3 network. Set up multiple sets of parallel experiments to classify normal and abnormal water quality in different environments. The results showed that the CNN convolution neural network model had a water quality recognition rate of 99.38%, which met the requirements of water quality identification.
2019 Vol. 40 (4): 721-727 [Abstract] ( 330 ) HTML (1 KB)  PDF (1458 KB)  ( 1113 )
728 Evaluation of Measurement Uncertainty in the Determination of Vitamin D2 and Vitamin D3 in Cosmetics
WANG Tao,LIU Peng-ming,DU Hui,FAN Fei,YANG Hui-ge,LI Jing-jing,ZHENG Yan
DOI: 10.3969/j.issn.1000-1158.2019.04.30
Uncertainties from the determination procedure of vitamin D2 and vitamin D3 in "Safety and Technical Standards for Cosmetics"(2015 Edition) by high performance liquid chromatography (HPLC) were assessed. The mathematical model was established, and each source and uncertainty component were analyzed. The combined standard uncertainty and expanded uncertainty were reported at last. The results showed that the expanded uncertainties were 10.36 μg/g and 9.71 μg/g (95% confidence level, k=2) when the content of Vitamin D2 and Vitamin D3 in cosmetics were 48.84 μg/g and 45.76 μg/g. The main sources for the uncertainty were discussed, and suggestions for improvement were also introduced.
2019 Vol. 40 (4): 728-735 [Abstract] ( 315 ) HTML (1 KB)  PDF (417 KB)  ( 569 )
736 The Chromatic Quantitative Testing Method of Cotton Sugar Content Based on Principal Component Model F
LI Shuai,LIU Rui,JIA Li-xia,JIN Chong-ye,JIA Dong
DOI: 10.3969/j.issn.1000-1158.2019.04.31
In order to solve the problem of poor linear fitting fluctuation between the single chromatic parameter and standard sugar solution with chromatic quantitative testing method (CQTM) and to take the advantages of comprehensive evaluation of multi index colorimeter, based on the relationship between the chromatic parameters and the 3, 5- two hydroxyl toluene-sulfuric acid, the principal component analysis method was used to reduce the dimension of chromatic parameters, and the relationship between the principal component model F and the standard sugar content was established. By measuring test of the cotton sugar content, the feasibility of this method was proved. And it was considered that this model F has advantages of the selectable chromatic parameters, controllable linear fitting fluctuation and omissible blank solution.
2019 Vol. 40 (4): 736-741 [Abstract] ( 284 ) HTML (1 KB)  PDF (739 KB)  ( 302 )
742 Effect of Fluorescence Properties of Fluorescent Film Materials on the Measurement Results of Fluorescence Microscope Analysis
XU Pei-pei,ZHANG Ling,HUANG Fei,WANG Fei,YE Zi-hong
DOI: 10.3969/j.issn.1000-1158.2019.04.32
The accuracy of the data measured by the fluorescence microscope is influenced by the linear dynamic range, the uniformity of the light field, and the stability of the light source. Fluorescence microscopy experiments were carried out on fluorescent microscopy materials, and it was found that fluorescence characteristics such as fluorescence linearity, uniformity and stability are important for fluorescence microscopy analysis. The spectral characteristics, linearity, uniformity, and light stability of fluorescent film materials were studied, a method for measuring the fluorescent properties of fluorescent film materials was established, a preliminary exploration of the calibration method for fluorescent microscopes was made, and the foundation for the calibration of fluorescent microscopes was laid.
2019 Vol. 40 (4): 742-748 [Abstract] ( 282 ) HTML (1 KB)  PDF (1026 KB)  ( 590 )
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