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2020 Vol. 41, No. 4
Published: 2020-04-28
 
393 Nucleic Acid Detection of the SARS-CoV-2 Hot!
ZHANG Yong-zhuo, WANG Jing, FU Bo-qiang, HUANG Xiang, DONG Lian-hua, NIU Chun-yan, YANG Jia-yi
DOI: 10.3969/j.issn.1000-1158.2020.04.001
The ongoing global Corona Virus Disease (COVID-19) outbreak is a public health emergency of international concern. It is very important to speed up the diagnosis and confirmation detection of suspected cases and quickly distinguish the disease of COVID-19 from other diseases. The novel coronavirus pneumonia diagnosis and treatment plan issued by National Health Committee of the People’s Republic of China has stipulated the nucleic acid detection of the 2019-Novel Coronavirus(2019-nCoV/SARS-CoV-2). The detection methods of nucleic acid PCR and sequencing, including real time quantitative Polymerase Chain Reaction(PCR), digital PCR detection and gene sequencing method were described to virus nucleic acid detection. A long time monitoring and biometrology standard system related to biosafety were prospected.
2020 Vol. 41 (4): 393-398 [Abstract] ( 416 ) HTML (78 KB)  PDF (646 KB)  ( 1000 )
399 Construction and Experimental Study of Micro-area Raman OpticalSystem Based on Differential Confocal Microscopy Technology Hot!
JIANG Jing-zi, GAO Si-tian, HUANG Lu, LI Qi, LIAN Xiao-yi
DOI: 10.3969/j.issn.1000-1158.2020.04.002
A micro-area Raman optical system based on differential confocal microscopy technology is developed to detect the micro-area Raman spectroscopy of inorganic samples. The traditional confocal Raman spectroscopy technology does not emphasize the focusing ability of the system, but the optical system device has the function of long-time focusing by using on the characteristic that the zero-crossing point of the differential confocal curve corresponds precisely to the focal point position and adopting feedback control technology. When collecting Raman scattering signals in micro-area, multi-mode optical fiber spatial coupling technology is used to replace traditional physical detection pinholes with optical fiber, which improves the anti-interference ability of the environment and optimizes the system structure and adjusting performance. The experimental results show that the device has high stability and can effectively detect the Raman frequency shift of single-walled carbon nanotubes at 1581.510cm-1, 2708.065cm-1 characteristic peaks and the Raman frequency shift of pure sulfur at 153.113cm-1, 219.917cm-1, 473.322cm-1 characteristic peaksand realize the single-line detection of the carbontube. The device meets the design requirements of the spectral detection system.
2020 Vol. 41 (4): 399-405 [Abstract] ( 338 ) HTML (1 KB)  PDF (2301 KB)  ( 423 )
406 Inspection on Surface Morphology and Sphericity Error of ICF Capsule Hot!
FEI Zhi-gen, WANG Kai-chuang, ZHOU Qiang, GONG Xiao-yun
DOI: 10.3969/j.issn.1000-1158.2020.04.003
In order to accurately measure the surface morphology and sphericity error of ICF capsule, a five-axis coordinate measuring machine is designed and the laser probe based onconoscopicholography is used. Firstly, according to the structural characteristics of the capsule surface, the sphericity error evaluation algorithm based on least squares is improved.Then, the overall configuration of a five-axis coordinate measuring machine(CMM)is introduced as an experimental platform, the measurement mathematical model of the CMM is deduced. The points on the capsule surface can be collected under a variety of gestures in the non-contact way. Finally, five measurement were made under the same working condition, the results of the experiments show that the average value of sphericity error of capsule is 0.0021mm and its standard deviation is 2.07×10-4mm. The proposed method can meet the measurement requirement of high accuracy and high stability upon the sphericity error of capsule.
2020 Vol. 41 (4): 406-412 [Abstract] ( 399 ) HTML (1 KB)  PDF (1650 KB)  ( 503 )
413 Design and Development of Vacuum Mercury Fixed PointBlackbody Radiation Source Hot!
LI Kai, HAO Xiao-peng, SONG Jian, SUN Jian-ping, HU Chao-yun, LIU Yang, HU You-hua, YANG Yan-long
DOI: 10.3969/j.issn.1000-1158.2020.04.004
The structure, working principle, performance test results and uncertainty analysis of the vacuum mercury fixed point blackbody radiation source developed by NIM, China, were introduced. The perfusion metal of the vacuum mercury fixed point blackbody was high purity mercury with a purity of 99.9999%. The opening diameter of the blackbody cavity is 25 mm, the inner diameter of the cavity is 28 mm, the depth is 260mm, and the surface is coated with high emissivity coating from NEXTEL 811-21. The Monte Carlo calculation method was used to calculate the blackbody emissivity at the wavelength of 8~14μm. The emissivity is higher than 0.9999. In the vacuum environment, the main technical indicators such as the temperature curve and repeatability of the temperature of the mercury fixed point blackbody were tested. The results show that the temperature stability of the vacuum mercury fixed point blackbody is better than 2mK, and the repeatability is better than 1mK. The uncertainty source of the vacuum mercury fixed point blackbody is analyzed, the synthetic standard uncertainty is better than 16mK.
2020 Vol. 41 (4): 413-418 [Abstract] ( 342 ) HTML (1 KB)  PDF (1332 KB)  ( 453 )
419 Study on the Realization of Gallium Melting Point Plateau Hot!
LI Li-feng, LI Rui, YAN Xiao-ke, WANG Ning, HE Pei
DOI: 10.3969/j.issn.1000-1158.2020.04.005
The gallium melting point is an important defining fixed point in the International Temperature Scale of 1990 (ITS-90) and plays a crucial role in temperature measurement researche. When the phase transition of the high-purity gallium from the liquid state to the solid state happens, the volume expansion is about 3.1%, which can result in the rupture of the conventional glass container of the gallium point cells during the freezing process. In order to solve this problem, a gallium melting point device was developed with a metal shell. Effects of realization methods and devices on the gallium melting plateaus were carried out. At the same time, a comparison was conducted between a similar foreign device and the developed cell. The experimental results showed that the temperature difference of the temperatures of the gallium melting point was consistent within of 0.02 mK, which may be attributed to the trace impurities in high-purity gallium samples. The temperature of gallium melting point realized with the outer liquid-solid interface method was 0.09 mK lower than that of the temperature obtained by the two-liquid-solid interface method. Effects of the realization apparatus on the gallium melting plateaus were small.
2020 Vol. 41 (4): 419-424 [Abstract] ( 344 ) HTML (1 KB)  PDF (1532 KB)  ( 316 )
425 Measurement of Carbon Dioxide Concentration Based on Multi-pass Absorption Technology Hot!
MA Ruo-meng, LIN Hong, ZHANG Liang, FENG Xiao-juan, FANG Li-de, ZHANG Jin-tao
DOI: 10.3969/j.issn.1000-1158.2020.04.006
Excessive emission of carbon dioxide is the main cause of greenhouse effect, which has a profound impact on the global environment and ecosystem. The carbon dioxide emitted from fuel combustion is the main source of urban area. In order to achieve the emission reduction through carbon emission trading, it is necessary to accurately measure the carbon dioxide in the enterprise chimney. The carbon dioxide content emitted by the enterprise chimney is generally below 20%, so it is necessary to establish a high-accuracy field measurement method. The multiple reflection absorption spectroscopy technology is used to accurately obtain (30012)←(00001) R18e transition line information of carbon dioxide at 6361.25cm-1, furtherly combines the ideal gas equation to accurately obtain the concentration of 15%, 10%, 5% and 1% carbon dioxide/nitrogen (nitrogen as balance gas) mixtures. The results show that the established device and technique can be used to measure the CO2 concentration efficiently and accurately. The measurement results are equivalent to that based on gravimetric method, and the relative expanded uncertainty is less than 0.65%(k=2).
2020 Vol. 41 (4): 425-429 [Abstract] ( 440 ) HTML (1 KB)  PDF (962 KB)  ( 1023 )
430 Research on Method of Measuring Pulsating Flowrate with Differential Pressure Flowmeter Hot!
ZHANG Yong-sheng, ZHANG Yi-zhi, LIU Yan-jun
DOI: 10.3969/j.issn.1000-1158.2020.04.007
Based on the theoretical model of differential pressure flowmeter under the condition of pulsating flow, the algorithm of calculating instantaneous pulsating flow by double-channel differential pressure is given. The flow field in Venturi tube is simulated by FLUENT software, and then the calculation method of pulsating flow is verified. The simulation results show that the maximum error can be up to 100% when calculating the fluctuating flow by single-channel pressure, and the maximum error can be reduced to about 5% when calculating the fluctuating flow by double-channel differential pressure.
2020 Vol. 41 (4): 430-433 [Abstract] ( 319 ) HTML (1 KB)  PDF (371 KB)  ( 360 )
434 Study on Measurement of Two-phase Gas-liquid Flow Based on Coaxial Phase Hot!
FANG Li-de, LANG Yue-xin, ZHAO Ning, LI Xiao-ting, WEI Zi-hui
DOI: 10.3969/j.issn.1000-1158.2020.04.008
In order to accurately measure the void fraction of gas-liquid two-phase flow, a coaxial phase difference measurement method was proposed. The coaxial line sensor was used to obtain the void fraction of the mixed medium by measuring the change of the phase difference after the electromagnetic wave was distributed through the gas-liquid mixed medium having different distribution conditions in the coaxial line. The design of the coaxial line measurement circuit and the measurement sensor were completed, and a void fraction measurement model was established. Subsequently, the indoor static experiment was carried out with gas-liquid two-phase. The error analysis of the sensor response and experimental results under the vertical tube state was carried out. The results show that the phase difference output is linear with the void fraction. At the same time, the relative error between the prediction result and the experimental result is within ±5% at different frequencies, indicating that the prediction model has better accuracy.
2020 Vol. 41 (4): 434-440 [Abstract] ( 313 ) HTML (1 KB)  PDF (1070 KB)  ( 744 )
441 The Hysteresis Modeling of Pneumatic Muscle Based on Least Squares Support Vector Machine Approach Hot!
XIE Sheng-long, ZHANG Wen-xin, LU Yu-jun, ZHANG Wei-min, ZHU Jun-jiang, LIN Li, REN Guo-yin
DOI: 10.3969/j.issn.1000-1158.2020.04.009
The traditional hysteresis modeling methods have series problems such as many parameters to be identified, complex parameter identification process and low identification accuracy, thus the least squares support vector machine (LS-SVM) approach is proposed to characterize the hysteresis phenomenon of pneumatic muscle(PM). The method maps the original data space to the high-dimensional space by non-linear mapping, thus the non-linear problem of the original system is transformed into a linear problem in the high-dimensional space, the least square method is used to solve the system of linear equations, which improves the speed of solution and convergence accuracy. Based on the experiments, the mathematical model of displacement/pressure hysteresis on PM was established by using LS-SVM method, the calculation results showed that the mathematical model established by LS-SVM has higher modeling accuracy and various error indices such as mean variance and mean error are significantly reduced, which reduce 99.21% and 99.1% respectively compared with the classical PI model. The method providing an effective means for subsequent hysteresis compensation control of PM.
2020 Vol. 41 (4): 441-447 [Abstract] ( 370 ) HTML (1 KB)  PDF (1445 KB)  ( 538 )
448 Uncertainty Evaluation on the Traceable Measurement System ofthe Impact Force Based on a Monte Carlo Method Hot!
JIANG Wen-song, WANG Zhong-yu, LUO Zai, ZHANG Li, HU Xiao-feng
DOI: 10.3969/j.issn.1000-1158.2020.04.010
A Monte Carlo method (MCM) is applied to evaluate the uncertainty of a traceable measurement system of the impact force with multi-component characteristics. First, the uncertainty components are represented by analyzing its error generation principles. Second, the relative error of adjacent solutions are applied to build the fitness function of the sample size. Third, the inputs of the traceable measurement system can approximate the population distribution by dynamic regulating the sample size of the MCM. The MCM is verified by applying its model to a traceable measurement system of the impact force. The experimental result shows that the relative expansion uncertainty is 0.818% with 95% degree of confidence. It reveals that both the inhomogeneous distribution of acceleration and the lateral oscillations on the hammer are the main uncertainties of this system.
2020 Vol. 41 (4): 448-454 [Abstract] ( 379 ) HTML (1 KB)  PDF (1495 KB)  ( 503 )
455 Rolling Bearing Fault Diagnosis Based on Maximum Amplitude Variational Mode Decomposition and Root Mean Square Entropy Hot!
MENG Zong, YUE Jian-hui, XING Ting-ting, LI Jing, YIN Na
DOI: 10.3969/j.issn.1000-1158.2020.04.011
The setting of modal number in the variational mode decomposition is very important for the decomposition results, based on this, a method to obtain the optimal decomposition layer number is proposed. The method is based on amplitude characteristics of the instantaneous frequencies and determines the optimal decomposition parameter by analyzing the relationship between the maximum amplitude of each component in the variational mode decomposition process. The root mean square entropy can reflect the energy of different vibration signals and is used as the characteristic parameter of the fault. And a fault classification model is established by optimized support vector machine to realize fault patterns classification. The fault diagnosis method based on maximum amplitude variational mode decomposition and root mean square entropy is applied to the measured signal of rolling bearings. The results show that the method based on maximum amplitude variational mode decomposition and root mean square entropy can identify rolling bearing running state efficiently and realize rolling bearing fault diagnosis. The recognition accuracy of this method is 98.75%.
2020 Vol. 41 (4): 455-460 [Abstract] ( 298 ) HTML (1 KB)  PDF (718 KB)  ( 540 )
461 Research on Measurement Method of Electrical Impedance of Transducer under High Hydrostatic Pressure Hot!
JIA Meng-wen, ZHAO Peng, WANG Yue-bing
DOI: 10.3969/j.issn.1000-1158.2020.04.012
To solve the problem that electrical impedance of the transducer cannot be measured accurately by the impedance analyzer with continuous wave in small size cavity, a transducer impendence measurement method based on pulse sine signal excitation under high hydrostatic pressure is proposed.Based on the sampling resistance method, the number of sinusoidal pulses and measurable frequency range are determined by the cavity size to effectively eliminate the influence of the boundary reflection.Different transmission frequencies are setted and voltage waveform signals upon the transducer and sampling resistor are collected.The admittance is calculated while the phase difference and amplitude are obtained by three-parameter sine wave curve-fit method.Admittance characteristic is measured with pulse sine signal method under the water pressure ranging from 0 to 10MPa.The experimental results show that sinusoidal pulse method is proved to be a better choice to measure the admittance characteristics of transducers in a limited space, and that the resonant frequency of the transducer shifts, and the diameter of the admittance circle decreases as the pressure increases.
2020 Vol. 41 (4): 461-468 [Abstract] ( 410 ) HTML (1 KB)  PDF (1607 KB)  ( 412 )
469 Research on AC Power Measurement System and Method Based on Josephson Quantum Voltage Hot!
JIA Zheng-sen, WANG Lei, XU Xi-tong, ZHOU Tian-di, PAN Xian-lin, SHI Zhao-min, ZHANG Jiang-tao
DOI: 10.3969/j.issn.1000-1158.2020.04.013
An AC power differential measurement system was designed based on the Josephson quantum voltage standard.By analyzing the error distribution and error transfer function of the differential sampling system, the sampling switching differential measurement method was proposed, which reduced the gain error of the differential sampling system and improved the accuracy of voltage amplitude measurement.By analyzing the attenuation coefficient η, it was proved that it is easy to realize voltage amplitude measurement of 10-7 magnitude by using switching differential measurement.By evaluating the zero phase of the differential sampling system, the results showed that the differential sampling system has better phase measurement stability.The uncertainty component of the AC power differential measurement system was analyzed, and the power measurement uncertainty of the power factor of 1.0, 0.5L and 0.5C was evaluated. Through the experimental comparison with the AC power national reference instrument, the rationality of the power measurement of the AC power measurement system based on Josephson quantum voltage was proved.
2020 Vol. 41 (4): 469-474 [Abstract] ( 377 ) HTML (1 KB)  PDF (883 KB)  ( 490 )
475 A Supraharmonics Dynamic Analysis Method Based onSliding-window TLS-ESPRIT Algorithm Hot!
ZHUANG Shuang-yong, ZHAO Wei, ZHAO Dong-fang, HUANG Song-ling
DOI: 10.3969/j.issn.1000-1158.2020.04.014
A dynamic analysis method of supraharmonics based on sliding-window TLS-ESPRIT(SWTLS-ESPRIT)is proposed. Firstly,a certain length of supraharmonics voltage and current signals was cut into many equal-length consecutive data blocks by rectangle window. For each data block,the number of supraharmonics is estimated.Secondly,the frequency and attenuation factor of the supraharmonics are estimated by the basic TLS-ESPRIT algorithm.Then the amplitude and phase of the supraharmonics are calculated using least square algorithm.Finally,the supraharmonics spectrum is displayed in three dimensions to realize the dynamic analysis of supraharmonics.The simulation analysis and the verification results of two kinds of nonlinear loads show that the proposed method is a more accurate measurement method for further study of supraharmonics,which can not only accurately estimate the supraharmonics frequency,attenuation factor,amplitude and phase with higher frequency resolution,but also can showthe time-varying characteristicof the supraharmonics bythe three-dimensional image.
2020 Vol. 41 (4): 475-483 [Abstract] ( 352 ) HTML (1 KB)  PDF (1270 KB)  ( 409 )
484 Research in Measurement and Application of New Type Quantum Hall Resistance Sample Hot!
CAI Jian-zhen, HUANG Xiao-ding, PAN Pan
DOI: 10.3969/j.issn.1000-1158.2020.04.015
A new type Quantum Hall resistance (NQHR) sample of AsGa epitaxial wafer was developed. The NQHR sample has multi structures. The characters and application area were introduced. The NQHR sample was compared with standard Quantum Hall resistance(QHR) sample using transition comparison measurement method. In laboratory, the measured valve deviation between the two kinds of sample is less than 4×10-8. The experiment proved that the accuracy of NQHR sample and metrology system could satisfy the application of QHR Standard in resistance metrology.
2020 Vol. 41 (4): 484-488 [Abstract] ( 365 ) HTML (1 KB)  PDF (1059 KB)  ( 450 )
489 Analysis and Uncertainty Evaluation of Capacitance Measurement of Supercapacitors by Constant Current Discharge Method Hot!
XU Feng, LI Zhi-wei, FENG Jian
DOI: 10.3969/j.issn.1000-1158.2020.04.016
Capacitance is one of the main electrical parameters of supercapacitors, and constant current discharge method is recommended to measure the capacitance of supercapacitors in related standards. Influences of the charging and discharge current, the initial terminal voltage of the capacitor were analyzed based on experiments. And uncertainty of the capacitance measurement was evaluated. Results show that the discharge current has a great influence on the measurement, and the capacitance decreases as the discharge current increases. The charging current and initial voltage have a small effect. The expanded uncertainty of capacitance measurement is 2.2% by constant current discharge method with a confidence factor of 2.
2020 Vol. 41 (4): 489-493 [Abstract] ( 458 ) HTML (1 KB)  PDF (586 KB)  ( 304 )
494 Research on Calibration Method and Device of High Voltage Short-circuit Test Measuring System Based on Arbitrary Waveform Generator Hot!
ZHOU Xiao-meng, LIN Zhi-li, MIAO Ben-jian
DOI: 10.3969/j.issn.1000-1158.2020.04.017
A method for injecting standard short-circuit test waveforms into a multi-channel arbitrary waveform generator to generate simulated actual calibration waveforms and then calibrating the measuring systems was proposed. A calibration device were developed using devices such as field programmable gate array (FPGA) and direct digital synthesizer (DDS). The verification results of the calibration device show that the maximum error of the output frequency and output voltage are 2.1×10-6 and 3×10-3 in the frequency range of 10Hz~200kHz. Repeated output 10 times, the maximum relative standard deviation of the output amplitude is 5.7×10-4, and the maximum relative standard deviation of the amplitude change within 1 year is 1.9×10-4. By using the device for calibration of the actual high voltage short-circuit test measuring system, it is verified that the noise, zero drift and bandwidth of the test waveform have a significant impact on the accuracy of the measuring system.
2020 Vol. 41 (4): 494-499 [Abstract] ( 367 ) HTML (1 KB)  PDF (628 KB)  ( 291 )
500 Research on Heave Data Test System of Inertial Navigation Equipment Hot!
XU Xin-ping, WANG Rui, YUAN-Jing, YANG Fan, LU Li-xun
DOI: 10.3969/j.issn.1000-1158.2020.04.018
A calibration system based on STM32 single chip and single axis swing table was developed.The calibration system utilizedtriangular relationship within a circle with fixed center and fixed radius, and collected the heave data in the composite motion of the single-axis rocking table through the wire sensor. At the same time, the calibration system collected and processed the heave data which were outputed by the inertial navigation device. The calibration system outputing heave data was verified. The test results shown that the calibration systems measurement data was accurate and reasonable. The calibration system can realize the dynamic measurement of the heave parameters of the inertial navigation device, which compensated for the shortcomings of the complex structure and small range of existing calibration systems.
2020 Vol. 41 (4): 500-504 [Abstract] ( 350 ) HTML (1 KB)  PDF (1327 KB)  ( 233 )
505 Self-Defined Fuzzy Clustering C-Means Algorithm Based on Improved Bat Optimization Hot!
TANG Zheng-hua
DOI: 10.3969/j.issn.1000-1158.2020.04.019
For the fuzzy clustering C-means algorithm is sensitive to the initial clustering center and clustering slow convergence, manually set the number of clusters and other defects, self-defined fuzzy clustering C-means algorithm based on improved bat optimization was proposed.Based on the density peak value, the density of data and the distance between cluster centers were measured, so as to automatically determine the number of cluster centers and clusters, which was used as the initial center of the improved bat algorithm.The Levy flight characteristics were introduced to enhance the bat algorithm to jump out of the local optimum ability, and Powell local search was used to accelerate bat algorithm convergence.The improved bat population was used for population optimization, and the optimal bat position was used as the clustering C-means new clustering center, and fuzzy clustering was carried out to obtain the clustering results by repeated iterative iterations.Compared with the other two clustering algorithms on the standard dataset, the experimental results showed that the proposed clustering algorithm can converge quickly with lower error rate.
2020 Vol. 41 (4): 505-512 [Abstract] ( 306 ) HTML (1 KB)  PDF (2224 KB)  ( 439 )
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