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2024 Vol. 45, No. 9
Published: 2024-09-28
 
1249 Application of microwave resonance method in high temperature acoustic gas thermometer
The difference between the thermodynamic temperature T and the international temperature scale ITS 90 T90 at temperatures higher than 335 K is important for the temperature community in the world. Acoustic gas thermometry, based on the determination of thermodynamic temperature from the speed of sound in gases, is one of the promising methods for this temperature range. The speed of sound in gases could be measured from acoustic resonant frequency and the inner dimension of the cavity. Microwave resonance method is a technical route for real-time and in-situ measurement of cavity size and thermal expansion at high-temperature. We optimized the high-temperature acoustic gas thermometry system to improve the temperature and pressure stability. Homemade high-temperature microwave cable and sensor were used for the measurement of microwave resonant frequencies in a cylindrical cavity from 335 K to 493 K with a relative standard deviation of (2~13)×10-8. The variation of the cavity size with temperature was obtained through microwave resonance frequencies. The stability of geometric of the cylindrical cavity was acceptable. Then the refractive index and pressure of the gas inside the cylindrical cavity were determined for analyzing the pressure difference from flowing gas. These results are helpful for future determination of T-T90 above 335 K with low uncertainties.
2024 Vol. 45 (9): 1249-1256 [Abstract] ( 6 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1257 Research of Constant Temperature and Velocity Water Bath for Calibration of Temperature Sensors’ Dynamic Response
Dynamic response is a key performance of temperature sensors in important and safety occasions. The constant temperature and velocity water bath is the core equipment for the calibration of temperature sensors` dynamic response. Due to the slow heating rate in typical annular rotating water bath, a novel electrically heated annular rotating water bath was developed based on the precision sliding ring, and the temperature fluctuations and velocity fields of the novel bath were tested. The results show that the heating up time is shortened, the temperature fluctuation is significantly less than ±1.0% of the step temperature, the vertical velocity uniformity is significantly better than 10% of the novel bath. The time constants of a sheathed resistance thermometer and a sheathed thermocouple were measured by the existing jet rotating water bath and the novel bath. The deviations from the existing bath results are 4.1% and 7.5%, respectively. These meet the engineering requirement. The novel bath provides good constant temperature and velocity environmental conditions for the dynamic response calibration of temperature sensors.
2024 Vol. 45 (9): 1257-1261 [Abstract] ( 10 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1262 The Methods and Prospects of Temperature Measurement for Chip Development in Micro-nano Meter Scale
Temperature measurement in micro-nano meter scale is crucial in the design, manufacturing, and packaging of chips. It can provide high-precision temperature information for tiny-scale regions and reflect the heating situation of the chip. The current temperature measurement technology is unable to meet the increasing performance demands of chips. Traditional contact temperature measurement methods such as thermocouple have high precision, but slow response rate, it is difficult to achieve wide field thermal imaging. Non-contact methods such as infrared radiation can achieve rapid thermal field measurement, but the accuracy is low and the wavelength is limited. The traditional temperature measurement methods are inadequate for achieving high precision, rapid temperature measurement at micro-nano scales. With the development of quantum precision temperature measurement technology, diamond negatively charged nitrogen-vacancy(NV-) center temperature measurement technology based on solid quantum spin effect is expected to solve the above problems, breaking through the existing micro-nano scale temperature measurement in the development of chip application bottleneck. In view of this, we first review the characteristics and development status of the existing chip temperature measurement technology, and then analyze the characteristics of diamond NV- center temperature measurement, miniaturization and integration technology trends. Finally, the technical advantages and application prospects in the field of chip development are prospected, and the challenges facing its development are put forward.
2024 Vol. 45 (9): 1262-1272 [Abstract] ( 7 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1273 Coarse aggregate particle size distribution of inference based on MCMC algorithm research
Machine vision is used to collect data on the coarse aggregate dropped from the vibrating plate, and a "pseudo-three-dimensional" image of the dynamic aggregate is obtained. Since the image information cannot accurately express the aggregate Therefore, the idea of Bayesian statistical inference is introduced to infer the particle size distribution of aggregates.The equivalent Feret short diameter is selected as the image feature, but the error between the Feret short diameter and the actual particle size of the aggregate is large when the particle size is large, so the equivalent elliptical short diameter is added as the second feature.In order to obtain accurate posterior distribution and efficient engineering computing capabilities, the Markov-Monte Carlo (MCMC) algorithm is used, thus breaking through the problem of insufficient high-dimensional calculations of traditional Bayesian statistical inference, and thus obtaining the aggregate Posterior distribution of particle size distribution.Experimental results show that the particle size distribution measurement error of this method for qualified aggregates is maintained within ±2.5%, and the error for unqualified aggregates is maintained within ±3.5%.
2024 Vol. 45 (9): 1273-1280 [Abstract] ( 9 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1281 Study on a receiving device for a laser detection system for sea surface oil spills
Oil film thickness is an important index for quantitative analysis of sea surface oil spill pollution. Previous studies have shown that laser detection of sea surface oil film thickness is feasible. However, at present, some important technical problems such as the series transformation of the laser signal through the receiving device of the system and the failure of the spectrometer to work properly due to the strong laser reflection signal have not been discussed. Because of this, a receiving device suitable for sea surface oil spill laser detection system is studied, which is mainly composed of optical components such as a collimator, optical antenna, and integrating sphere, by studying the optical structure of each part of the device. A series of problems such as the energy transmission and transformation of laser in the device are analyzed. Finally, the laser reflection signal intensity corresponding to different oil film thicknesses is taken as the simulation parameter to verify the effectiveness of the receiving device under different sea conditions. The results show that the laser intensity through the receiving device is much less than that without the receiving device under the same oil film thickness. In addition, under the calm sea surface or the micro-wave sea surface with wind speeds of 0.3m/s, 0.5m/s, and 0.8m/s, the laser intensity after the receiving device can be used to retrieve the oil film thickness effectively. It is proved that the receiving device of the sea surface oil spill laser detection system studied in this paper can not only reduce the laser intensity to ensure the normal operation of the spectrometer in a certain intensity range but also effectively receive and process the signal reflected from the sea surface oil spill and its energy transmission and transformation model.
2024 Vol. 45 (9): 1281-1290 [Abstract] ( 9 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1291 Position error of touch-trigger probe based on mandrel calibration on the process of gear on-machine measurement
The geometric position of probe is calibrated by a reference sphere on most of mainstream gear measuring instruments. Compared to the reference sphere, the reference mandrel is not only easy to be installed and operated, but also it can detect the static accuracy of the machine tool. So the probe calibration in this paper is conducted by the reference mandrel in the process of gear on-machine measurement on a new developed gear grinding. To improve the calibration accuracy of probe position, the calibration of probe geometric position is defined by the least squares method (LSM), which can fit the center of reference mandrel. Simultaneously, the algorithm based on Aitken iteration, which is used on the basis of LSM, is built to compensate the error of position produced by LSM. This method replaces the nonlinear fitting iterative process with linear convergent numerical sequence, which not only has a faster convergence rate, but also tends to be stable. The effectiveness of this method can be validated through the experiment of tooth profile evaluation, and it can provide the useful guidance for the geometric position calibration of other gear measurement.
2024 Vol. 45 (9): 1291-1299 [Abstract] ( 10 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1300 Study on Regression Prediction Method of Multi signal Spindle PSO-SVM Rotation Error Based on LMD
In order to solve the problem that the original signal type used in the prediction of spindle rotation error of CNC machine tools is too single and the eigenvalue selection is insufficient, this paper adopts a regression prediction method of spindle rotation error based on the combination of multiple signals and eigenvalue optimization algorithm. Firstly, the complex vibration signal, current signal and acoustic emission signal of the main shaft are decomposed into the sum of several product function (PF) components with physical significance by using local mean decomposition (LMD) method; Secondly, the time-frequency domain eigenvalues of the main PF components (product function components) in the three signals are extracted; The Pearson coefficient between the rotation error and the eigenvalue is calculated to optimize several eigen-values, and the eigenvalue with the strongest correlation with the spindle rotation error in each PF component is obtained, which is used as the input parameter to predict the spindle rotation error; Finally, the spindle rotation error is accurately predicted by establishing the support vector machine prediction model from the eigenvalue to the spindle rotation error. The results show that when the three spindle signals are used as inputs, the rotation error prediction model is better. At the same time, combined with the optimization algorithm of eigenvalue, the effect of the particle swarm optimization support vector machine rotation error prediction model is the best. The mean square error, determination coefficient, and average absolute error of the test set sample set can reach 0.27%, 0.9094, 4.48%. It provides an effective method for on-line pre-diction of spindle rotation error.
2024 Vol. 45 (9): 1300-1313 [Abstract] ( 7 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1314 Improved YOLOv5s UAV aerial forest fire smoke detection
To solve the problems of low detection accuracy and high calculation cost of traditional forest fire smoke detection, a forest fire smoke detection algorithm based on improved YOLOv5s is proposed. A fire and smoke dataset containing 16573 images is constructed to solve the problem of insufficient existing data sets and improve the generalization ability of the training model. A lightweight GC-C3 module is designed to replace the original C3 module and reduce the number of model parameters and calculation. The weighted bidirectional feature pyramid network is integrated into the Neck structure to enhance the detection ability of the network for small and medium targets. The network space pyramid pool structure is modified, SPPF is replaced by SimSPPF structure, and the computing efficiency and detection accuracy of the network are improved. The bounding box regression loss function CIOU is replaced by Focal-EIOU to accelerate the convergence of the model and solve the problem of mismatch between positive and negative samples. The experimental results show that the average detection accuracy of the improved network is increased by 2.3%, the number of model parameters is decreased by 46.7%, and the calculation amount of the model is decreased by 47.5%.
2024 Vol. 45 (9): 1314-1323 [Abstract] ( 11 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1324 Fractional Parameters Calibration for Particle Image Velocimeter
The calibration methods of particle displacement and cross-frame time during particle image velocimetry (PIV)measurement are studied. The geometric size standard of disc is designed for camera calibration, the proportional relationship between the image obtained by camera and the object is determined, and the particle displacement calibration is realized by comparing with the ruler under the same experimental condition. A traceable timer is used to calibrate the time interval of PIV synchronizer pulse signals at different speed points. The cross-frame time correction coefficient is the ratio of the actual value to the initial value. As the result the PIV calibration coefficient is determined by the particle displacement correction coefficient and the cross-frame time correction coefficient. The uncertainty of PIV calibration results based on the sub-parameter method is evaluated. The results indicate that: At the theoretical speed point of 100m/s, the maximum relative error is 0.08%, and the uncertainty of the relative error is 0.01%.
2024 Vol. 45 (9): 1324-1330 [Abstract] ( 9 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1331 Research and design of oil well liquid phase correlation metering system
Aiming at the problems of low automation and large error of existing oil well measurement methods, an oil well liquid phase correlation metering system was designed by using coaxial line phase method water content meter. In order to realize the synchronous measurement of both flow rate and water content, the correlation flowmeter was constructed by the coaxial line phase method water content meter. Moreover, the measurement model was established by cross-correlation method. Through the analysis of the upstream and downstream water content meter signals under different circumstances, it can be seen that there is a correlation between the two signals, to meet the conditions for the use of the correlation flowmeter. Compared with the turbine flowmeter in field tests, the average error of the system was 11.36%. The results proved the feasibility of the system in practical applications.
2024 Vol. 45 (9): 1331-1338 [Abstract] ( 5 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1339 Research on online performance evaluation method of ultrasonic gas flowmeter
In this paper, a new method of on-line evaluation of ultrasonic flowmeter performance based on Bayesian information fusion is proposed. The principle is to establish a change point detection model based on Bayesian information fusion method, obtain the change trend of measurement data, and realize the real-time performance evaluation of ultrasonic flowmeter. The specific implementation process is to combine the prior information with the real-time sample information and iteratively update the posterior distribution, where the posterior standard deviation in the posterior distribution is the real-time uncertainty of the instrument. Compared with the traditional uncertainty evaluation method, this method integrates real-time measurement information, which can continuously evaluate the uncertainty of the instrument in real time, monitor the operation of the entire measurement system of the ultrasonic flowmeter, and find out the abnormal working conditions in time, and realize the online evaluation of the flowmeter performance. This provides a new method and way for online monitoring of ultrasonic flowmeter, so as to improve the quality and efficiency of industrial production.
2024 Vol. 45 (9): 1339-1347 [Abstract] ( 5 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1348 Optimization of Flow Measurement Uncertainty in Open Channel With Triangular Thin-Walled Weir Based on Data Fitting Method
Aiming at the problem of low accuracy level of the triangular thin-walled weir open channel meter when it is not used at fixed point, the research on the measurement method was carried out based on the results of the uncertainty pre-assessment. Curve fitting is proposed to replace linear interpolation to calculate the flow coefficients, and a digital output magnetostrictive water level sensor is adopted to measure the water head, which significantly reduces the uncertainty component of the original method. The frequency sampling method is improved based on the Froude's similarity criterion, which improves the accuracy level of the measurement results. The uncertainty of the measurement method was improved from 1.6% to 0.56%. The calibration experiments of the triangular thin-walled weir open-channel flowmeter were carried out by the standard meter method open-channel flow rate standard device, and the experimental results showed that the calibration error (deviation) was reduced from 2% to 1% after the improvement of the measurement method.
2024 Vol. 45 (9): 1348-1352 [Abstract] ( 10 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1353 Image Reconstruction of Electrical Capacitance Tomography Based on Deep Wavelet Networks
The image reconstruction algorithm based on deep wavelet network is proposed to address the problem of low reconstruction accuracy due to the "soft field" effect and unsuitable characterization in the image reconstruction process of capacitive tomography. The Landweber algorithm is used to generate the initial reconstructed image as the input of the network. Taking the U-Net deep convolutional neural network model as the backbone model, the wavelet transform is introduced into the upper and lower sampling layers to extract the features of different levels and the high-frequency feature transfer channel is built through a skip connection to retain more detailed information and make full use of global and local information features in the feature map. The simulation and experimental results show that the proposed image reconstruction algorithm has higher image reconstruction accuracy and better reconstruction quality. The average relative image error of the reconstructed image is 0.1918, and the average correlation coefficient is 0.9685.
2024 Vol. 45 (9): 1353-1359 [Abstract] ( 7 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1360 Self-supervised learning combined with adversarial transfer for cross-conditions bearing fault diagnosis
In the application of intelligent bearings fault diagnosis, it is extremely difficult to obtain sufficient real fault data due to the complexity and variability of the actual working conditions, and there exist large differences between the signals in the target and source domains, leading to the problems of difficult feature extraction and classification and weak generalization of the model in the cross-working condition transfer recognition of the deep model. Considering the existence of a large amount of unlabeled data in the target domain, this paper introduced unsupervised ideas and proposed an improved method based on self-supervised learning combined with adversarial transfer. Firstly, the pretext tasks are created based on the characteristics of the signal itself to learn from a large amount of unlabeled data and establish the intrinsic connections of fault categories between the source domain and the target domain; then the knowledge learned from the source domain is transferred to the target domain through adversarial domain adaptation and joint maximum mean difference, and finally, it combined with the pretexts task to optimize the difference between the two domains and achieved accurate fault classification in the target domain. Experimental results have verified the feasibility and good performance, which can achieve better diagnostic results and generalization of the model compared to other methods.
2024 Vol. 45 (9): 1360-1369 [Abstract] ( 8 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1370 Study on the sparse imaging method of deep learning electrical impedance block based on DK-SVD
iming at the ill-posedness and nonlinearity of electrical impedance tomography inverse problem, a DK-SVD-based block sparse image reconstruction method is proposed. The multi-layer perceptron is introduced to finetune optimal model parameters for measurement data considering the complexity of datasets and improve the image quality. The iterative shrinkage threshold algorithm is used to accelerate convergence in the sparse coding stage. The simulation results show that the structural similarity of the reconstructed image by DK-SVD algorithm can reach more than 0.95, the error can be controlled at about 0.1, and the average reconstruction speed is 0.034s, which effectively improves the quality and efficiency of electrical impedance tomography, and further experiments prove that the algorithm has good noise robustness and practical application value.
2024 Vol. 45 (9): 1370-1377 [Abstract] ( 4 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1378 Analysis on the axial magnetic field of multi-layer finite solenoid based on the equivalent current density model
In order to resolve the calibrating problem of axial Hall magnetic probe with short rob, a portable finite solenoid was proposed as the reference magnetic field generator. The axial magnetic filed was calculated to obtain its distribution based on the Biot-Savart law and superposition principle of magnetic field, by establishing the solenoid model in a cylindrical coordinate system. In addition, a finite element model (FEM) was established for the multi-layer finite solenoid to analyze its spatial magnetic filed with given exciting current. A solenoid prototype with 100mT central magnetic intensity was designed according to above theoretical analysis. The data from the ECD model, FEM and prototype testing were compared, and the results show that at the solenoid center the deviation between theoretical calculation and FEM is less than 0.1%, and it’s less than 0.8% between theoretical calculation and prototype testing. It’s demonstrated that the ECD model is effective to analyze solenoid axial magnetic field. This method is suggested to be applied in designing and optimizing parameters of a finite solenoid more efficiently and accurately.
2024 Vol. 45 (9): 1378-1383 [Abstract] ( 10 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1384 Research On Early Warning Of Abnormal Working Conditions Of Wind Turbine Based On QM－DBSCAN And BiLSTM
Abstract: A wind turbine fault warning method based on quartile method(QM)－density-based spatial clustering of applications with noise(DBSCAN) and Bi-directional long and short-term memory network (BiLSTM) is proposed. Firstly, in view of the difficulty of cleaning the power limit point in the wind speed-power diagram, the combination of QM and DBSCAN is proposed to preprocess the modeling operation data; secondly, by analyzing the operation principle of wind turbine and determining the input and output parameters of the normal working condition prediction model of wind turbine combined with LightGBM feature selection method, a high-precision normal performance prediction model of wind turbine is established based on BiLSTM. Then, the state performance index of the fan is determined by the sliding window algorithm, and the index threshold is determined by statistical interval estimation method. Finally, the real fault data of the fan is used to carry out the early warning experiment of the abnormal working condition of the whole wind turbine, which verifies the effectiveness of the method.
2024 Vol. 45 (9): 1384-1393 [Abstract] ( 7 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1394 Evaluation of the Phase Frequency Response of Digitizing Oscilloscopes
Aiming at the difficult problem of obtaining the phase difference between the response waveform and the excitation signal in the calibration of phase frequency characteristics of digital oscilloscopes, a method is proposed that utilizes the pulse amplitude triggering functional characteristics. By setting the triggering condition and the amplitude relationship of the excitation signal, the phase point of the excitation signal corresponding to the waveform of the response signal is fixed, so as to accurately obtain the phase shift characteristics of the tested digital oscilloscope, And unified the reference phase points for phase shift characteristics at different frequencies, successfully obtaining the phase frequency response characteristic curve of the digital oscilloscope. In a set of experiments, the effectiveness and feasibility of the method were verified, which can be used for measuring and evaluating the phase frequency response characteristics of digital oscilloscopes.
2024 Vol. 45 (9): 1394-1400 [Abstract] ( 9 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
1401 Analysis of The Measurement Comparison Results of On-wafer S-parameters
As the leading laboratory, the 13th Research Institute of China Electronics Technology Group Corporation carried out the measurement comparison of on-wafer S-parameters, summarized and analyzed the measurement results of on-wafer S-parameters submitted by the joined laboratories, and evaluated the measurement results of each laboratory with En. Through the measurement comparison of the on-wafer S-parameters, the accuracy and reliability of the transmission of the quantities are ensured, especially the main sources of the measurement uncertainty of the on-chip S-parameters are unified. At the same time, it also provides the industry with a comparison platform for the consistency of on-chip S-parameter measurement.
2024 Vol. 45 (9): 1401-1406 [Abstract] ( 8 ) HTML (0 KB)  PDF  (0 KB)  ( 1 )
1416 The Latest Development of International Standards for Dose Monitoring Instruments of Ionizing Radiation
With the continuous progress in the radiation protection, the international standards related to ionizing radiation dosimeters are also continuously updated and iterated. In order to summarize the development status of IEC and ISO standards in the field and provide reference for the production and selection of dosimeters, by researching and comparing the content of different versions of relevant standards, summarized the development overview of relevant IEC and ISO standards and the modifications and updates made in the latest version for the dose monitoring instruments of photon, β and neutron, as well as the differences in performance requirements and specifications for various aspects of instruments between the different current standards were compared. It was found that the international standards under each monitoring category tended to be unified in the development process, no longer divided by detector types, etc. Moreover, the overall application scope of these standards was broader, but the relevant standards of dose measurement instruments for pulsed radiation still need to be developed. And different standards applicable to the same monitoring classification had basically the same performance requirements for instruments, however, due to the different purposes and application scenarios of IEC and ISO standards, there were differences in the focus of performance requirements and specifications between the two.
2024 Vol. 45 (9): 1416-1424 [Abstract] ( 9 ) HTML (0 KB)  PDF  (0 KB)  ( 0 )
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