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2023 Vol. 44, No. 5
Published: 2023-05-28
 
671 Research on the Method of Nanometer Grating Spacing Comparison Measurement Based on Cr Atomic Lithography Technology
CHEN Kai-qing,GUAN Yu-qing,ZOU Wen-zhe,DENG Xiao,KONG Ming,CHEN Ya-qing,XIONG Ying-fan,FU Yun-xia,LEI Li-hua
DOI: 10.3969/j.issn.1000-1158.2023.05.01
A method of nanometer grating spacing comparison measurement based on Cr atomic lithography technology is established. Based on the feasibility of establishing a calibration traceability system for standard templates based on national self-traceable grating reference materials, it ensures higher precision and traceability of measuring instruments . Precision nanometer measuring instruments that can be adapted to different resolutions, sequentially increasing multi-period electron beam direct writing grating template was designed and fabricated, the nominal pitch values are 200, 400, 600, 800, 1000nm. After the national self-traceable grating reference material comparison, AFM completed the measurement and characterization of the nano-grid standard sample. The experiment shows that the uniformity level of the grating standard sample prepared by electron beam direct writing is less than 1nm, and the uncertainty is less than 2%. The gratings have good uniformity, accuracy and stability, which verifies that the developed grating standard template can be used as an ideal physical standard in the traceability system of nano-geometric quantities. A method of nanometer grating spacing comparison measurement based on Cr atomic lithography technology is established. Based on the feasibility of establishing a calibration traceability system for standard templates based on national self-traceable grating reference materials, it ensures higher precision and traceability of measuring instruments (AFM, SEM, etc.); In order to meet the needs of high-precision nanometer measuring instruments that can be adapted to different resolutions, sequentially increasing multi-period electron beam direct writing grating template was designed and fabricated, the nominal pitch values are 200nm, 400nm, 600nm, 800nm, 1000nm. After the national self-traceable grating reference material comparison, AFM completed the measurement and characterization of the nano-grid standard sample. The experiment shows that the uniformity level of the grating standard sample prepared by electron beam direct writing is less than 1nm, and the uncertainty is less than 2%. The gratings have good uniformity, accuracy and stability, which verifies that the developed grating standard template can be used as an ideal physical standard in the traceability system of nano-geometric quantities. The nanometer grating spacing comparison measurement method based on Cr atomic lithography technology can provide a guarantee for the development and breakthrough of countrys nano-industry.
2023 Vol. 44 (5): 671-678 [Abstract] ( 146 ) HTML (1 KB)  PDF (47170 KB)  ( 92 )
679 A Milling Cutter Wear Monitoring Method Based on ABiGRU
LIU Chao,WANG Chen,ZHANG Xiu-feng,LU Xu-xiang
DOI: 10.3969/j.issn.1000-1158.2023.05.02
In order to accurately monitor tool wear in the milling process, a tool wear monitoring model based on attention and bidirectional gated recurrent unit (ABiGRU) was proposed. In the monitoring model, firstly, the time series data collected by vibration, force, and acoustic emission sensors were analyzed in the time domain, frequency domain, and time-frequency domain, and spearman coefficient was used to extract 20-dimensional features strongly correlated with the average rear tool surface wear. Secondly, the ELU activation function was introduced to optimize the BiGRU network and solve the gradient disappearance problem, in the meantime, the internal attention mechanism was used to improve the models ability to capture important feature information and quickly realize the mapping from feature to tool wear value. Finally, compared with RNN, LSTM, GRU, BiLSTM, and BiGRU, the results shown that the model could not only accurately characterize the tool wear degree, but also the accuracy and efficiency is improved greatly.
2023 Vol. 44 (5): 679-686 [Abstract] ( 141 ) HTML (1 KB)  PDF (86019 KB)  ( 83 )
687 A Fast Minimum Circumscribed Circle Error Evaluation Method Based on Outer Enveloping Points
GAN Jiang-hong,WANG Jie,XU Mei-hong
DOI: 10.3969/j.issn.1000-1158.2023.05.03
The high-precision roundness measurement of large-scale shaft parts will generate a large sample measurement point set, the rapid minimum circumscribed circle(MCC) error evaluation based on the large sample point set has become an urgent engineering problem to be solved. The MCC can be determined by the outer enveloping points of the ordered points set. An enveloping vector model of the ordered point set was established to find the outer enveloping points, and the outer enveloping points were compressed to a constant number. The MCC would be obtained in a short time based on the compressed outer enveloping points. Meanwhile, the generality, efficiency and practicability of the proposed method were verified by the literature data, the simulation data and measured data respectively. The fast MCC error evaluation method based on outer enveloping points is simple and high efficient, which is suitable to improve the MCC calculating algorithm of present roundness tester.
2023 Vol. 44 (5): 687-693 [Abstract] ( 118 ) HTML (1 KB)  PDF (80944 KB)  ( 66 )
694 Robust Stereo Matching Algorithm Based on Improved Census Transform
QIAO Jing-hui,HAN Yu-ming,ZHANG Xiao-han
DOI: 10.3969/j.issn.1000-1158.2023.05.04
Aiming at the problems of the noise and illumination sensitive and with high false matching radio in the weak texture region of the local matching algorithm, an robust stereo matching algorithm for improved Census transform and adaptive parameter-guided filter is proposed. The hue, saturation, value(HSV) channel value is used to calculate the cost, which has higher robustness to noise and illumination changes. In the support window, the distance weighting and color weighting are used to obtain the reference value of the census transform respectively. The two costs are fused to improve the stability of the single pixel matching cost. The kurtosis adaptive regularization parameter is used on the guide filter for cost aggregation. Finally, the disparity map is obtained by disparity calculation. The matching experiment is carried out on the image pairs provided by Middlebury database on the VS2017. The average error matching rate of the proposed algorithm of standard image, noisy image and illumination change image is 7.80%, 10.72% and 9.89% respectively. The results show that the algorithm can reduce the false matching ratio and better adapt to the changes of noise and illumination.
2023 Vol. 44 (5): 694-700 [Abstract] ( 138 ) HTML (1 KB)  PDF (72315 KB)  ( 97 )
701 Study on Defects Detection Method of Mobile Phone Curved Glass
CHEN Ning,GUO Gang-xiang,GUO Bin,ZHANG Yue,WANG Chao,KONG Ming,CHEN Ting,WANG Ying-hui,ZHAO Jian-ming,WU Jian
DOI: 10.3969/j.issn.1000-1158.2023.05.05
Due to some appearance defects in the production process of curved glass of mobile phone, a defect detection method of curved glass of mobile phone was proposed to solve the problems of difficult imaging and extraction of defects on curved glass. Firstly, shape matching was carried out on the curved glass plane images, and the matched images were processed by difference and morphology to extract the defect features. Secondly, a defect extraction algorithm based on connected domain analysis and area threshold segmentation was used for curved glass images. Thirdly, the image frequency domain enhancement and logarithmic transformation defect extraction algorithm were used for the R-angle image of curved glass. Finally, after extracting the defects of each part, the characteristics of all kinds of defects were calculated, and the defects were classified according to the characteristics, and the obtained defect data was compared with the data obtained by the image measurement instrument. The results showed that the algorithm can accurately extract the common scratches, stains, abrasions and bubbles on the curved glass surface of mobile phones, and the size accuracy of the defects can reach 20μm.
2023 Vol. 44 (5): 701-706 [Abstract] ( 157 ) HTML (1 KB)  PDF (46122 KB)  ( 98 )
707 Analysis of Continuous Temperature Measurement Sensitivity Based on Nitrogen-vacancy Centers in Diamond
XING Li,FENG Xiao-juan,ZHANG Jin-tao
DOI: 10.3969/j.issn.1000-1158.2023.05.06
The temperature measurement based on nitrogen-vacancy (NV-) centers in diamond has the merits of ultra-high sensitivity and micro-nano spatial resolution, which is realized through the zero-field splitting energy generated by spin-spin interaction between the two unpaired electrons in the outermost layer of the NV- center. Usually, analysis of sensitivity is used to judge the signal to noise ratio of the output signal. In order to improve the sensitivity, the theoretical model of continuous temperature measurement sensitivity without an applied magnetic field is derived, and the main interfering factors are analyzed. The effects of microwave antenna diameter, laser and microwave power on the linewidth and fluorescence contrast of optically detected magnetic resonance (ODMR) are optimized. The relationship between zero-field splitting energy D and temperature T is calibrated in the range of 303K to 318K. The coefficient dD/dT is -73.42kHz/K and the relative standard deviation is 5.3%. Finally, the sensitivity at different temperature is measured, and the low-frequency average sensitivity reaches the level of 0.5K/Hz1/2(＜10Hz).
2023 Vol. 44 (5): 707-713 [Abstract] ( 165 ) HTML (1 KB)  PDF (124393 KB)  ( 107 )
714 Temperature Measurement of Fluid in a Tube Usinga Microwave Cylindrical Cavity Resonator Sensor
LI Qin-qin,WANG Tian-qi,YU Hao-yan,BIAN Chuang,LI Zhen
DOI: 10.3969/j.issn.1000-1158.2023.05.07
A new method for measuring the temperature of the fluid in a tube is proposed, which is based on the measurement of the complex permittivity of the liquid using a microwave resonant cavity, and combines the Debye and Cole-Cole equations to obtain the temperature value of the measured liquid. Firstly, the shortcomings of the commonly used methods for measuring the temperature of the fluid in the tube are briefly introduced. Secondly, the working principle of the measurement system is introduced in detail. Taking the two working modes of TM010 and TM011 as examples, the measurement of pure water is carried out. By comparing the measurement results in the two working modes, it is confirmed that the proposed method can achieve fast and accurate temperature measurement while accurately measuring the complex permittivity of the tested material. The measurement results show that the calculation method of the imaginary part of the Cole-Cole equation has the smallest error in the TM010 mode. The proposed method can solve the problems of large safety hazards and complex solutions in the current measurement of fluid temperature in the pipe.
2023 Vol. 44 (5): 714-721 [Abstract] ( 129 ) HTML (1 KB)  PDF (135310 KB)  ( 99 )
722 Influence of Sample Temperature Field of Double Infrared Laser Temperature Calibration Source on Measurement Results
GU Qing-tao,WANG Xin-yu,AN Bao-lin,ZHAI Hui-xing,DONG-Wei,WANG Rui-xiang
DOI: 10.3969/j.issn.1000-1158.2023.05.08
Active dual-wavelength infrared laser temperature measurement can realize emissivity free temperature measurement. The instrumental constant is the core parameter of the temperature measuring system. At present, the determination of the instrumental constant depends on the temperature of the center point on the surface of the calibration sample. In the process of temperature measurement and calibration, when the detection position of the surface of the calibration sample deviates from its central point, the result of the instrument constant will be affected. But the temperature field distribution outside the central point and its influence on the temperature measurement results are scarce. Therefore, The numerical modeling of the calibration samples is carried out to analyze the distribution of temperature fields of different samples and their influence on the measurement results. The results show that the temperature distribution on the front surface of the sample is approximately center-symmetric. The center temperature is low and the edge temperature is high. The temperature from the center to the edge increases rapidly first and then slowly with the direction of the radius. The influence of different deviation degree of calibration sample position on the instrumental constant is analyzed. When the calibration temperature is 1173K and the calibration position offset is ±5mm, the effects of the calibrated instrumental constants of superalloy, low emissivity coating sample and SiC are 1.87%, 1.06% and 0.79%, respectively. The influence of the instrumental constant on the temperature measurement results is further analyzed. The mean relative deviations of the superalloy, low emissivity coating sample and SiC due to the instrumental constant deviation are 0.34%, 0.20% and 0.14%, respectively, in the temperature measurement range of 873~1073K.
2023 Vol. 44 (5): 722-728 [Abstract] ( 116 ) HTML (1 KB)  PDF (106836 KB)  ( 92 )
729 Ultrasonic Waves Peak-valley Fitting Method and Two-Dimensional Flow Velocity Measurement in Planar Cascade
QUE Yi-fei,YU Tian-yang,ZHANG Shi-wei,Ma Liang,SU Ming-xu
DOI: 10.3969/j.issn.1000-1158.2023.05.09
In order to accurately obtain time difference information of ultrasonic propagation in complex two-dimensional flow fields, a signal processing method for determining echo characteristic points by polynomial fitting of ultrasonic peak and trough amplitude is investigated and applied to one-dimensional and two-dimensional flow velocity measurement. A measuring device of multi-channel ultrasonic velocity is developed. In the range of 0~40m/s flow rate, the device is used to acquire one-dimensional flow ultrasonic signal. The maximum relative error between the results obtained by the peak-valley fitting and those of the pitot tube is 0.72% lower than that calculated by the peak fitting method. A methodology for calculating two-dimensional flow velocity by means of time difference of diagonal transducers is proposed to conduct the measurement of two-dimensional flow velocity during a series of experiments in a planar cascade flow channel. The relative errors between the experimental flow velocities and those measured by the three-hole probe at different working conditions are all under 3.16%. It also effectively reflects the change trend of velocity at measuring points from magnitude to direction due to the change of channel section and blade bending at different inlet flow velocities.
2023 Vol. 44 (5): 729-734 [Abstract] ( 115 ) HTML (1 KB)  PDF (94283 KB)  ( 78 )
735 Gas-liquid Two-Phase Flow Pattern Analysis Based on Multilayer Weighted Complex Network
ZHANG Li-feng,WANG Zhi,ZHANG Qi-liang
DOI: 10.3969/j.issn.1000-1158.2023.05.10
A flow pattern analysis method based on multi-layer weighted complex networks is presented.Firstly,the electrical resistance tomography system is used to obtain the flow information of gas-liquid two-phase flow in vertical rising pipeline,and the measured data are compressed to simplify the data analysis.Then the multi-scale decomposition is carried out by using the multi-dimensional empirical mode decomposition algorithm, so the flow system can be mapped to the multi-layer weighted network. The network structure is described quantitatively by calculating the average weighted aggregation coefficient and spectral radius. The final results show that the network model can effectively reveal the evolution process from bubble flow to slug flow, from bubble aggregation to gas slug gradual breaking, and from pseudo periodicity to decline can be reflected by the changes of network parameters.
2023 Vol. 44 (5): 735-742 [Abstract] ( 124 ) HTML (1 KB)  PDF (164059 KB)  ( 50 )
743 Uncertainty Evaluation and Verification of 2~4MPa Gas Flow Standard Facility
ZHANG Han,WANG Liang,HUANG Dong-hong,DONG Xin-li,Li Chun-hui,LI Yong,Dong Xiang-min,ZHAO Liu,ZHANG Qian
DOI: 10.3969/j.issn.1000-1158.2023.05.11
In order to meet the traceability requirements of city gas flow meters, the gas flow standard facility was built based on master meter method. As the non-fixed usage of master meters and the low temperature of natural gas, the uncertainty evaluation and control of the standard facility were investigated. The results showed that the standard facility used four turbine flowmeters as master meters and has mobility, while the achievable flowrate range was within 60~8600m3/h and the pressure range of 2~4MPa. The uncertainty of the non-point usage of the master meters was controlled based on the curve fitting method, while the uncertainty of the city gas flow standard facility was 0.26% (k=2). Compared with NIM-2014, NIM-2015 was more suitable for master meters with scattered error curves. On this basis, the heat transfer model of low-temperature natural gas flow in pipeline was established. It was found that the dynamic temperature balance of the facility can be achieved through a longer pre-flow time, which can improve the measurement repeatability, the uncertainty of the calibrated flowmeter was 0.32% (k=2).
2023 Vol. 44 (5): 743-749 [Abstract] ( 143 ) HTML (1 KB)  PDF (49612 KB)  ( 107 )
750 Mechanism of the Disconnection of the Neutral Wire on the Measurement of the Three-phase Four-wire Electric Energy Meter
DIAO Rui-peng,WANG Qiang,LU Zhi-jun
DOI: 10.3969/j.issn.1000-1158.2023.05.12
To solve the problem that the phase voltage measurement value is higher than actual value and the measurement error are caused when the neutral line is disconnected for the three-phase four-wire linear power meter. The changing law of the potential drift of the neutral terminal of the electric energy meter from the working process of the three-phase circuit is explored, and the cause of the three-phase four-wire electric energy meter in the neutral line disconnection is analyzed theoretically. The reason is verified to verify the accuracy of the theoretical analysis by simulation and experiment, and a method of neutral line current monitoring is proposed to identify the disconnection of the neutral line, which provides a sufficient theoretical basis for identify the disconnection of the neutral line and improving the accuracy of measurenment.
2023 Vol. 44 (5): 750-757 [Abstract] ( 133 ) HTML (1 KB)  PDF (66812 KB)  ( 80 )
758 Modeling and Analysis of Redundancy of Battery Replacement for Electric Vehicles Based on Edge Computing
XIE Hu,CHEN Zhi-wei,GUO Wen-xin,ZHAO Rui-feng,LIU Yang
DOI: 10.3969/j.issn.1000-1158.2023.05.13
In order to solve the problem of high battery redundancy and high charging cost in electric vehicle power station, based on edge calculation,the modeling and analysis of battery redundancy are studied. Combined with edge computing and cloud computing technology, an edge computing platform for analyzing the redundancy of electric vehicle battery is established. The edge node A is used to collect the electric vehicle electricity information, and the collected data is uploaded to the cloud platform. The cloud platform uses the electric vehicle battery charging optimization control model to analyze the edge node B associated with the electric vehicle battery redundancy, and solves the model using adaptive genetic algorithm to realize the optimization of battery charging. The experimental results show that the model can effectively analyze the battery redundancy of electric vehicle, and the monthly charging cost of the battery can be reduced by more than 13% when the model is applied to the electric vehicle exchange station.
2023 Vol. 44 (5): 758-764 [Abstract] ( 154 ) HTML (1 KB)  PDF (23361 KB)  ( 58 )
765 Study of the Deposition of Nb/Al-AlOx/Nb Josephson Junction Trilayer
GAO He,WANG Shi-jian,XU Da,LI Jin-jin,WANG Xue-shen,ZHONG Qing
DOI: 10.3969/j.issn.1000-1158.2023.05.14
Low temperature superconducting devices based on Nb/Al-AlOx/Nb Josephson junctions are widely used, one of the keys to fabricate high-quality S-I-S Josephson junctions is to deposit high-quality Nb/Al-AlOx/Nb trilayer. Many property parameters can influence the quality of trilayer, such as the residual resistance ratio(R.R.R),superconducting transition temperature (Tc),surface roughness,film stress, the thickness of aluminum(Al) film and so on. By analyzing the relationships of the parameters above with different sputtering conditions, the best deposition condition can be determined. Also, different critical current densities of Nb/Al-AlOx/Nb trilayer can be obtained by controlling the oxidation pressure and time of Al.
2023 Vol. 44 (5): 765-770 [Abstract] ( 166 ) HTML (1 KB)  PDF (59550 KB)  ( 114 )
771 The Influence of Digital Multimeter Input Impedance in DC High Voltage Dividers Measurement
LIU Fang-ming,XIAO Kai,WANG Hai-yan,LIU Hao,KUANG Yi
DOI: 10.3969/j.issn.1000-1158.2023.05.15
Voltage division and subtraction of low-voltage side was used in the DC high voltage dividers measurement.It was generelly assumed that digital multimeter imput impedance has certain effects on the measurement,so far the assuming was lack of theory basis and experimental datas.To prove the assuming, an experiment is carried out and sereval valuable data is presented.Further more,an impact factor of the measurment effect is given out by building the methemetical model, and a revised method is proposed to amend the measurment.The contrast experiment proves that the bias of corrected result is better than 0.01%.
2023 Vol. 44 (5): 771-776 [Abstract] ( 155 ) HTML (1 KB)  PDF (21031 KB)  ( 182 )
777 The Estimation Algorithm of Eye Diagram Cross-point for Vector Network Analyzer
GAO Qiang,MA Shi-min,LIU Jie
DOI: 10.3969/j.issn.1000-1158.2023.05.16
Eye diagram cross-point estimation is an important step in eye diagram parameter calculation, which directly affects the calculation accuracy of eye width, peak-to-peak jitter and other parameters. The traditional method is based on the statistical characteristics of the data and requires a large amount of data to get more accurate results. Because the vector network analyzer generates eye diagrams more complicated than other instruments, it takes a long time to collect data when the amount of data is large, which affects the efficiency of the instrument. In order to solve this problem, an eye diagram cross-point estimation method based on local interpolation is proposed, which can still estimate more accurate results when the amount of data is small. Experiments show that when the estimation accuracy is 1.2×10-13s, the proposed method requires only 1/4 of the data of the traditional algorithm.
2023 Vol. 44 (5): 777-782 [Abstract] ( 106 ) HTML (1 KB)  PDF (21757 KB)  ( 75 )
783 Study on the Influencing Factors and Long-term Stability of the CT Number of Siemens Large Aperture CT Simulator
HU Jin-you,ZOU Lian,XIE Zhao,LUO Ke-lin,YIN Yun-peng,ZHANG Wei-sha
DOI: 10.3969/j.issn.1000-1158.2023.05.17
The influence of scanning parameters on the CT number of CIRS-062M phantom was studied by changing the current time product, voltage and reconstruction convolution kernel of Siemens CT simulator.The annual quality assurance data of CIRS-062M phantom and the monthly quality assurance data of CTP504 phantom were retrospectively analyzed to study the long-term stability of CT number.The results show that the current time product has almost no effect on the CT number, and the maximum change is 4.6HU.The voltage has great influence on the CT number, with the maximum change of 585.3HU. Except for the Head H31s and Child Head H21s convolution kernels, the other convolution kernels have slight influence on the CT number.The CT number of the two phantoms have maintained good consistency in recent years, the maximum change is dense bone in CIRS-062M phantom, with a maximum change of 63.3HU and an average change of (-8.68±17.82)HU.
2023 Vol. 44 (5): 783-789 [Abstract] ( 141 ) HTML (1 KB)  PDF (32155 KB)  ( 61 )
790 The International Key Comparison in Mammoraphy X-rays Air-kerma
WANG Ji, WU Jin-jie,GUO Si-ming,LIU Ying,WANG Pei-wei
DOI: 10.3969/j.issn.1000-1158.2023.05.18
In order to support mammography X-ray air kerma traceability system, NIM has completed the quantitative reproduction of the mammogram X-ray air kerma rate, with an uncertainty of 0.3%. And completed the the BIPM.RI(I)-K7 key comparison work with BIPM in 2018.The calibration factor deviation of the same two transfer ionization chambers is less than 0.04%, and the comparison result uncertainty is 0.28%.The comparison result enters the key comparison database of BIPM, achieving international mutual recognition.
2023 Vol. 44 (5): 790-795 [Abstract] ( 150 ) HTML (1 KB)  PDF (34204 KB)  ( 52 )
796 Small Field Output Factor Measurement and Verification Based on TRS-483
ZHANG Xi,WANG Zhi-peng,WANG Kun,HUANG Ji,QI Ya-ping,LIU Fu-bin,JIN Sun-jun
DOI: 10.3969/j.issn.1000-1158.2023.05.19
To measure small field output factor, the tissue-phantom ratio (TPR20,10(10)) of the Elekta Synergy linear accelerator nominal radiation energy of 6MV and 10MV were measured using TRS-483 report method published by IAEA, which were 0.683 and 0.735.By calculating the minimum FWHM applicable to the ionization chamber, various measurable radiation field ranges of the ionization chamber were verified. The FWHM of the selected ionization chambers are between 3～4cm.By comparing the sensitive volume, linearity of measured dose and dose rate, leakage current, repeatability and stability, a total of 21 detectors from 18 different models were selected.Under the condition of TPR20,10(10)=0.683, 0.735, source skin distance (SSD) of 90cm and 100cm, 1cm×1cm,2cm×2cm, 3cm×3cm, 4cm×4cm, 5cm×5cm and 8cm×8cm square field to 10cm×10cm square field output factors were measured and multiplied by the correction factor reported by TRS-483.The maximum difference between the corrected radiation field output factor and the mean value is less than 0.025.The results show that using the correction factor reported by TRS-483 can improve the consistency of measurement of small field dose by different detectors.
2023 Vol. 44 (5): 796-802 [Abstract] ( 114 ) HTML (1 KB)  PDF (70585 KB)  ( 67 )
803 Prediction of CO2 Physical Properties in Near-Critical Region Based on WOA-LSSVM Model
HE San,TANG Kai,ZHANG Mao-chao,XUE Ya-wen,XUE Shi-qi
DOI: 10.3969/j.issn.1000-1158.2023.05.20
Aiming at the problem that the existing CO2 state equation is difficult to accurately predict the physical parameters of CO2 in the near-critical region, the combination model (WOA-LSSVM) of the least squares support vector machine (LSSVM) optimized by the whale optimization algorithm (WOA) was adopted to predict the physical properties of CO2 in the critical region. The prediction results show that compared with the REFPROP software and the PSO-LSSVM model, the WOA-LSSVM model has higher accuracy in predicting the physical properties of CO2 in the near-critical region. Compared with REFPROP software, the WOA-LSSVM model reduces the root mean square error of density and viscosity prediction results from 133.67, 9.33 to 35.61, 1.58, and the average relative error from 31.8%, 30.25% to 6.88%, 3.88%, the coefficient of determination is 0.59, 0.62 to 0.86, 0.83. In addition, the proportion of relative errors below 10% increased from 0% to 69.23% and 92.31%.
2023 Vol. 44 (5): 803-809 [Abstract] ( 111 ) HTML (1 KB)  PDF (80452 KB)  ( 74 )
810 The Application of Standard Gas Mixture of SO2 and NO in Ecological Environment Monitoring Inter-laboratory Comparison
WU Xiao-feng,WANG De-fa,WU hai,Lü Yi-bing
DOI: 10.3969/j.issn.1000-1158.2023.05.21
Referring to the reference materials development technology, a patch of cylinders of SO2 and NO standard gas mixture in nitrogen was prepared by gravimetric method, and verified for applicability.The application of the gas mixture in ecological environment monitoring was investigated by inter-laboratory comparison.The results showed that the standard gas mixture was suitable to carry out inter-laboratory comparison and a good application effect was obtained in practical ecological environment monitoring inter-laboratory comparison.The laboratory comparison results show that the proportion of laboratories with satisfactory evaluation results for SO2 and NO are 79.4% and 81.4%, respectively, indicating that the overall detection ability and technical level of SO2 and NO in China are good.
2023 Vol. 44 (5): 810-817 [Abstract] ( 124 ) HTML (1 KB)  PDF (44329 KB)  ( 65 )
818 Applications of RNA Spike-in Quality Control for RNA Sequencing
ZHANG Yu,WANG Xia,ZHANG Yong-zhuo,YANG Jia-yi,NIU Chun-yan,ZHAO Yang,DONG Lian-hua
DOI: 10.3969/j.issn.1000-1158.2023.05.22
Eukaryotic transcriptome is diverse and complex. RNA sequencing (RNA-seq) can be used to provide a global profile of the transcriptome, find biomarkers associated with dieases and support the diagnosis and treatment of complex diseases. The process of RNA-seq includes sample preparation, library preparation, sequencing and analysis. The technical errors that are introduced during all the workflow influence the accuracy of RNA-seq. These errors can be understood and mitigated through the use of RNA spike-in, which can determine quality control for RNA-seq and improve the reliability of RNA-seq data. Therefore, RNA spike-in and its applications are introduced, including normalization between samples, gene expression measurements, detection and quantification of diverse transcripts, which provides powerful reference for improving the quality of RNA-seq by using RNA spike-in effectively.
2023 Vol. 44 (5): 818-825 [Abstract] ( 193 ) HTML (1 KB)  PDF (74203 KB)  ( 160 )
826 The Establishment of Digital PCR Quantitative Method for Strain B.1.1.7 of SARS-CoV-2
WANG Xia,GUO Ruo-hui,DONG Lian-hua
DOI: 10.3969/j.issn.1000-1158.2023.05.23
Due to B.1.1.7 (Alpha) being listed as a “variant of concern” by the World Health Organization (WHO), it is particularly important to establish a specific and highly sensitive digital PCR method for it. First, this method required designing primer probes based on the H69/V70 deletion, P681H, and A570D specific mutation sites of the mutant spike protein, and determining the linear range and limit of quantitation for the three methods. Subsequently, the specificity of the method was verified using four other “variant of concern”, and quantitative accuracy was compared using different digital PCR platforms and methods. Finally, the results indicated that the established digital PCR method was accurate and reliable, and can be used for quantitative detection of B.1.1.7 variant strains.
2023 Vol. 44 (5): 826-832 [Abstract] ( 117 ) HTML (1 KB)  PDF (98401 KB)  ( 66 )
833 A Further Short History of the SI Prefixes
理查德·布朗(Richard J C Brown)
DOI: 10.3969/j.issn.1000-1158.2023.05.24；10.1088/1681-7575/ac6afd
A short history of the development and adoption of the SI prefixes since 1964 is provided, following on from the last time a similar article was written, with special attention paid to the recent extension to the range of SI prefixes following the 27th General Conference on Weights and Measures in 2022. A brief future look is also presented.
2023 Vol. 44 (5): 833-836 [Abstract] ( 153 ) HTML (1 KB)  PDF (17015 KB)  ( 131 )
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