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2019 Vol. 40, No. 2
Published: 2019-03-22
 
177 Simiulation of AFM Scanning Process and Tip Shape Estimation
SHI Yu-shu,LIAN Xiao-yi,WANG Yi-xuan,HUANG Lu,DONG Ming-Li,HU Xiao-dong,GAO Si-tian
DOI: 10.3969/j.issn.1000-1158.2019.02.01
To accurate measure the line widths of nano-grid and step structure is the hottest issues in metrology domain. AFM can be used to obtain the three-dimensional topographic information of the above structure, but the scanned image is the result of the interaction between the shape of the tip and the surface morphology of the sample. This interaction often leads to line width edge measurement distortion. To more accurately obtain the surface topography of the sample, firstly, the shape of the tip needs to be reconstructed, and then the distortion effect brought by the tip topography is eliminated as much as possible from the scanned image. Based on the blind reconstruction theory of mathematical morphology, Matlab was used to simulate the stepped sample surface scanned by different shape parameters of tips, the influences of the probe tip shape on the scanning results were evaluated, and got the initial realization of probe tip shape reconstruction based on measuring rough surface.
2019 Vol. 40 (2): 177-182 [Abstract] ( 450 ) HTML (1 KB)  PDF (1643 KB)  ( 845 )
183 A Traceable Atomic Force Microscope
YANG Wen-jun,HU Chi,LIU Xiao-jun
DOI: 10.3969/j.issn.1000-1158.2019.02.02
A traceable atomic force probe microscope based on white light interference is developed. A robust white light interference zero-order fringe postioning algorithm is presented and a high-resolution displacement measurement system is established. On basis of above work, a probe calibration method is proposed to realize traceable measurement for micro-nano surface. A standard grating (step height: (21.4±1.5) nm) is tested 10 times under the same conditions, the measurement average value is 21.56 nm and the standard deviation is 0.51 nm. And a three-dimensional characteristic sample (step height: 150 nm) is used for 3D measurement. The accuracy and stability of the developed instrument have been verified by the experiments.
2019 Vol. 40 (2): 183-188 [Abstract] ( 379 ) HTML (1 KB)  PDF  (0 KB)  ( 165 )
189 Flatness Metrology—Value Transfer and Control of Point,Section and Surface
WANG Qing,GU Yang
DOI: 10.3969/j.issn.1000-1158.2019.02.03
Two transmission pathways of line and plane in flatness metrology were studied. Based on the absolute test of measuring points, a unified method for solving different flatness index systems on straight lines and plane domains was put forward. Aiming at the problem that the original definition of flatness cannot be maintained in circular optical flat witch tested by an equal thickness interferometer, and fringe spacings (N、ΔN) had to used in this scene. The influence on transfer accuracy of hypothesis and additional requirements in 《JJG 28—2000 Optical Flat》 which used for defining line with points and defining surface with lines was analyzed. Characteristic orthogonal sections which contain maximum change were proposed to replace the random orthogonal sections in 《JJG 28—2000 Optical Flat》. Based on the advantages of high resolution and rapid measurement of phase shifting interferometer, the method to search for the characteristic orthogonal sections was described. So, it can promote the rigorous of flatness in metrology.
2019 Vol. 40 (2): 189-195 [Abstract] ( 398 ) HTML (1 KB)  PDF  (0 KB)  ( 146 )
196 Research on Duplex Carrier Detection System Based on Machine Vision
SHI Yun-zhao,NI Jun,LI Ning-chuan,FAN Sheng-hua
DOI: 10.3969/j.issn.1000-1158.2019.02.04
The hardware design and mechanical structure of the dual-station carrier tape detection system based on machine vision are described. An image processing algorithm suitable for carrier tape detection is proposed, which mainly includes the defect detection algorithm and the size calculation algorithm. The algorithm uses the standard qualified carrier sample image as the training set, and acquires the characteristics of the detection area image from these standard qualified carrier sample images. The quantity information is used as a comparison standard for online detection. After the actual line test verification, the detection rate of the carrier defect is not less than 99.6%, the critical defect detection rate is 0%. The detection time of one frame of image is 10 ms, and the detection speed reaches 12 m/min.
2019 Vol. 40 (2): 196-200 [Abstract] ( 404 ) HTML (1 KB)  PDF  (0 KB)  ( 183 )
201 An Error Compensation Method on ABS Gear Parameters Measurement System
GAO Jun-peng,JIANG Tao,ZHANG Gui-lin
DOI: 10.3969/j.issn.1000-1158.2019.02.05
In order to correct the errors causing by swinging of bearings of ABS gear parameters measurement system, the method of least square curve fitting and affine transformation of space rectangular coordinate to correct the errors are used. Firstly, the coordinate transformation matrix is derived through analyzing the method theoretically. Secondly, the mathematical model is established according to the error correction method, the transformed coordinate formula is derived and the transformed contour data coordinates are calculated through plugging the parameters of measured coordinate system into transform formula. Finally, simulation experiment was carried out with Matlab. The experiment results show the deviation between the corrected coordinate error value and the actual error value is less than 1μm. The effect of various errors in the actual measurement process is solved, the measurement accuracy is improved.
2019 Vol. 40 (2): 201-207 [Abstract] ( 393 ) HTML (1 KB)  PDF  (0 KB)  ( 171 )
208 Absolute Test of Optical Planar by Closed Loop
ZHANG Ling-hua,HAN Sen,WU Quan-ying,TANG Shou-hong,LI Xue-yuan,WANG Quan-zhao
DOI: 10.3969/j.issn.1000-1158.2019.02.06
Based on the Ai C and Wyant J C method of odd and even functions, a four-step rotary absolute test method is proposed to reduce the number of rotations and select the rotation angle of the second measurement as 90°. Experiment is based on HOOL L9600A-HS3 interferometer, using four-step rotation absolute measurement method, the three planes test with each other to calculate the absolute surface of the three planes, in which the plane C surface topography height root mean square (RMS) value and peak valley (PV) are 3.460 nm and 35.227 nm. After closed-loop self-test, measurement results are 3.783 nm and 34.305 nm,3.669 nm and 34.252 nm, it indicating that the measurement data can be closed-loop self-test. Using this method, the plane of National Institute of Metrology in China is measured. The RMS value and and the PV value of the plane are 2.400 nm and 19.600 nm, respectively, which are compared with the measurement results of 2.000 nm and 16.000 nm of National Institute of Metrology. The measurement deviation is on the order of nm, the measurement results fully proves the effectiveness of the experiment and high repeatability. In addition, the experiment also analyzes the influence of temperature on the measurement results.
2019 Vol. 40 (2): 208-212 [Abstract] ( 364 ) HTML (1 KB)  PDF  (0 KB)  ( 177 )
213 Design of synchronous speed sensor of optical high-speed rotating-mirror camera
TANG Yuan-hong,WU Yun-feng,ZHANG Chen-yu,SHEN Lan-xiao,ZHAO Ling-ling
DOI: 10.3969/j.issn.1000-1158.2019.02.07
A synchronous rotating speed sensor for optical fiber rotating mirror high-speed camera is designed.A high accuracy digital measurement method is proposed by combining micro control unit (MCU ) and complex programmable logic device (CPLD ).MCU and CPLD communicate through serial peripheral interface (SPI),and MCU transfers the corresponding spark base delay and pulse width to CPLD.The detection signal is sent to CPLD for filtering and counting processing after enlarging and shaping.CPLD sends the measured data to the computer by serial port to the computer for real-time display, and simultaneously outputs the synchronous control signal.The test data show that the relative error of the time measurement is less than ± 0.2%.The error of the imaging system is about 4.5 mm, and the drift time is about 3μs,which meets the requirements of the experiment.
2019 Vol. 40 (2): 213-219 [Abstract] ( 399 ) HTML (1 KB)  PDF  (0 KB)  ( 178 )
220 Image Dehazing Based on Improved Dark Channel Prior Algorithm
CHENG Lei,LIU Yong-jun
DOI: 10.3969/j.issn.1000-1158.2019.02.08
In order to improve the effect of image dehazing, an improved dark channel prior (IDCP)algorithm was proposed. Transmittance was calculated accurately with narrow image and three dark channel prior linear fitting method,atmospheric light was estimated by four fork tree algorithm within a certain interval, color was compensated in order to avoid the image lower saturation. Experimental results show that IDCP is more refreshing and natural in vision, and the comprehensive evaluation value of different images is better than other algorithms.
2019 Vol. 40 (2): 220-224 [Abstract] ( 383 ) HTML (1 KB)  PDF  (0 KB)  ( 173 )
225 Measurement of Refractive Index of Argon Gas Using a Cylindrical Microwave Resonator
CHEN Wei,ZHANG Kai,FENG Xiao-juan,LIN Hong,ZHANG Jin-tao,DUAN Yuan-yuan,LU Jun
DOI: 10.3969/j.issn.1000-1158.2019.02.09
The refractive index of monatomic gases such as argon is an important parameter for the verification of the ab initio calculations based on quantum mechanics. The refractive index of argon from 234 K to 303 K and 0 kPa to 750 kPa was measured accurately using a cylindrical microwave resonator. Microwave resonance frequencies of four TM modes at different pressures in a cylindrical cavity were measured. After the correction of the non-ideal factors, the refractive index of argon was obtained by the comparison of the microwave resonance frequencies in vacuum and in gases. The uncertainty of microwave resonance frequency in the cylindrical cavity is 2×10-8, and the inconsistence between the argon refractive index from four modes is less than 1×10-6. The first dielectric virial coefficients of argon are obtained by calculating the refractive index of argon, and the results show a good agreement with the published results. The refractive index measurement of other gases can be carried out in the future using the experimental apparatus.
2019 Vol. 40 (2): 225-231 [Abstract] ( 355 ) HTML (1 KB)  PDF  (0 KB)  ( 160 )
232 Development of Blackbody Radiation Sources at Fixed Point on Satellite of Infrared Hyperspectral Atmospheric Detector
HU Chao-yun,HAO Xiao-peng,SONG Jian,WEN Ping,CHANG Jia-qiang,GU Ming-jian,DING Lei
DOI: 10.3969/j.issn.1000-1158.2019.02.10
The miniature gallium fixed point onboard blackbody radiation source developed by National Institute of Metrology for the infrared hyperspectral atmospheric detector of Fengyun No.3 05 satellite is introduced. The black body radiation source cavity is designed, and the effective emissivity of the black body radiation source is better than 0.997. The structure design and performance test of blackbody radiation source with fixed point on satellite are studied. Blackbody radiation source uses double heating, one PID control output, one constant power output. Thermal simulation of spaceborne fixed point blackbody radiation source at 17 ℃, the temperature uniformity result is better than 0.01 ℃. The results of uniformity and stability of blackbody radiation source in vacuum are better than 0.02 ℃ and better than 0.002 ℃ (within 90 min), respectively. The reproducibility of the gallium fixed point is better than that of 0.03 ℃ by satisfying the mechanical impact test of aerospace application. There is a good linear relationship between the heating power and the inflection point value in the micro-fixed point phase transition temperature plateau reappearance experiment.
2019 Vol. 40 (2): 232-239 [Abstract] ( 420 ) HTML (1 KB)  PDF  (0 KB)  ( 167 )
240 Development of Self-calibrated Infrared Radiation Thermometer for Surface of Ground or Water
CHANG Jia-qiang,HAO Xiao-peng,L Biao,HU Zhao-yun,SONG Jian,LI Kai,HAN Qi-jin
DOI: 10.3969/j.issn.1000-1158.2019.02.11
An instrument for measuring the radiation temperature of the ground or water surface with self-calibration function was developed. The design principle, specific structure, test procedure and final experimental results of the instrument were described. In order to verify the performance of the instrument, the emissivity measurement experiment of the calibration blackbody and the temperature stability test were carried out. The results show that the blackbody emissivity is higher than 0.996, and the temperature control stability is better than 0.04 K. The calibration of each temperature sensor was performed; The control and data acquisition procedures were completed; the radiation temperature measurement experiment of the prototype was carried out. Finally, the temperature range of the self-calibrated surface water meter infrared radiation thermometer is 223~333 K, and the temperature uncertainty is 0.2 K.
2019 Vol. 40 (2): 240-245 [Abstract] ( 339 ) HTML (1 KB)  PDF  (0 KB)  ( 170 )
246 Investigation on CO2 Concentration Measurementfor Point Emission Source
ZOU Bing-yan,LIN Hong,ZHANG Liang,FENG Xiao-juan,ZHAO Bu-hui,ZHANG Jin-tao
DOI: 10.3969/j.issn.1000-1158.2019.02.12
The global climate change caused by the increase in the concentration of greenhouse gases(GHG) in the atmosphere is the focus of attention in the world. Among all sources of emissions, the emission of carbon dioxide from point sources is a major factor in the greenhouse effect. The Intergovernmental Panel on Climate Change (IPCC) will directly measure emissions as the highest level of GHG emissions inventory statistics to improve the accuracy of data statistics. In order to achieve accurate measurement of emissions, direct measurement of point source concentration is critical. An off-axis direct absorption spectroscopy technique combined with a long optical path gas absorption cell and a scanning laser frequency method was used to establish a relative method for accurate measurement of carbon dioxide concentration. The absorption spectra of the (30012)←(00001)R20e transition line at 6362.5 cm-1 in the range of 293 K and 0~13 kPa have been measured. The concentration of 15%, 35%, 50%, and 75% of carbon dioxide mixture was obtained by comparison with the absorption area of pure carbon dioxide, and a detailed uncertainty analysis was performed on the measurement results. The results have a good consist with the results obtained by the balance weighing method, the expanded relative measurement uncertainty is below 0.7%(k=2).
2019 Vol. 40 (2): 246-251 [Abstract] ( 410 ) HTML (1 KB)  PDF  (0 KB)  ( 169 )
252 The Application of Multi-population Genetic Algorithm in Secondary Air Temperature of Grate Cooler
LIU Bin,ZHANG Chun-ran,SUN Chao,GU Xin-feng,LIU Hao-ran
DOI: 10.3969/j.issn.1000-1158.2019.02.13
Aiming at the problem of poor diversity and poor local optimization ability of the genetic algorithm, a multi-population genetic algorithm (MGA) was proposed. According to the theory of Punctuated Equilibria, the algorithm took the manipulation of multiple populations, and multiple crossover operators. Meanwhile, the MGA algorithm had also composed of the local search method and population dynamics adjustment strategy to improve the local search ability and speed. Compared with GA and ISGA algorithms, MGA running time is short and has a better optimization performance. Finally, the MGA algorithm was applied to optimize the multi-kernal least square vector mechaine(MKLSSVM) parameters. And then established the secondary air temperature model of the cement grate cooler based on MGA-MKLSSVM. The results show that this model has high recognition precision and strong generalization ability.
2019 Vol. 40 (2): 252-258 [Abstract] ( 322 ) HTML (1 KB)  PDF  (0 KB)  ( 190 )
259 Soft Sensor Model of Heat Rate Based on Optimized LSSVM by FEWOA
ZUO Zhi-ke,CHEN Guo-bin,LIU Chao,NIU Pei-feng,LI Yi-long
DOI: 10.3969/j.issn.1000-1158.2019.02.14
An integrated modeling method was proposed based on feedback elitist whale optimization algorithm (FEWOA) and least square support vector machine (LSSVM). Firstly, a feedback elitist WOA was proposed to solve the problem of low precision of the WOA. Based on the FEWOA, the current optimal solution was mutated to avoid the algorithm falling into local optimal solution by the elite strategy. Meanwhile, a feedback phase was introduced at the end of the position updating, so that the algorithm improves the precision. Numeric simulation results show that the proposed FEWOA exhibited superior performance over the other aforementioned algorithms. Then, a soft sensor model of heat rate based on optimized LSSVM by FEWOA was proposed. Finally, the turbine heat rate prediction model was established by using the operation data collected from a steam turbine generator set. The prediction results of FEWOA-LSSVM model were compared with the others, the result show that the FEWOA-LSSVM prediction model can predict the heat rate of steam turbine more accurately.
2019 Vol. 40 (2): 259-265 [Abstract] ( 386 ) HTML (1 KB)  PDF  (0 KB)  ( 163 )
266 Development of Four-channel Ultrasonic Gas Flow Transmitter Based on Variable Threshold and Zero-Crossing Detection
MU Li-bin,XU Ke-jun,LIU Bo,TIAN Lei,LI Jian-bo,SHEN Zi-wen
DOI: 10.3969/j.issn.1000-1158.2019.02.15
For the four-channel ultrasonic gas flow-meter, a digital signal processing method based on variable threshold and zero-crossing detection is proposed to locate the echo signals quickly and accurately and improve the anti-interference ability of the system. And the working process that centralized sampling-centralized processing of data and the transceiver way that double emission double receive were designed. A transmitter of four-channel ultrasonic gas flow-meter was developed based on FPGA & DSP dual core structure. It realizes the double emission double receive transceiver way, controls the high-speed ADC & DAC and storages the data by taking the advantage of the parallel processing capacity and better logic control ability of FPGA, completing the centralized sampling of data. On the other hand, it realizes the real time digital signal processing method by using the high-speed computing capacity of DSP, completing the centralized processing of data. The gas calibration experiment results show that the four-channel ultrasonic gas flow-meter developed meets the needs of the related technical indicators of the 0.5-level precision ultrasonic gas flow-meter.
2019 Vol. 40 (2): 266-271 [Abstract] ( 378 ) HTML (1 KB)  PDF  (0 KB)  ( 197 )
272 Dynamic Calibration of Towing Tank Speed Based on Laser Tracker
ZHU Yun-long,HU He-ming,JIN Zhong-jia,DOU Ying-wei,XIE Dai-liang
DOI: 10.3969/j.issn.1000-1158.2019.02.16
Towing tank usually measures its speed using a tachometer wheel, of which there is a systematic bias due to static calibration without considering dynamic characteristics. A dynamic calibration method of towing speed is introduced based on laser tracker. We firstly calibrate and correct the laser tracker on a long-rail speed facility, and then use it on the towing tank. Results show tachometer wheel with only static calibration has a lower indication, and the slower speed has the lower indication. It is better to use different encoder coefficients at different speeds. The uncertainty estimation method are also discussed, including the influence of towing speed stability and dynamic performance of the tachometer wheel.
2019 Vol. 40 (2): 272-277 [Abstract] ( 351 ) HTML (1 KB)  PDF  (0 KB)  ( 199 )
278 Uncertainty Analysis of Velocity Measurement in Low Pressure Flow Field
YANG Tie-niu,ZOU Sheng,WU Zong-yue,ZHAO Lei-lei,LU Dong-dong,YANG Ya
DOI: 10.3969/j.issn.1000-1158.2019.02.17
Laser Doppler velocimetry has been widely used in the field of flow measurement. Based on the experimental platform of vacuum airflow detection, a laser Doppler velocimeter was used to measure the gas-velocity of the vacuum chamber. In order to reduce the measurement error of the velocity measurement system, the source and evaluation of the measurement uncertainty of the vacuum chamber velocity were analyzed and explained. The relative standard uncertainty and the relative expansion uncertainty of the measurement of gas-velocity of the vacuum chamber are obtained. The results show that the uncertainty caused by LDV repetitive velocity measurement and air intake quantity estimation is relatively large, but the uncertainty caused by LDV system error and other factors are smaller. The results are of guiding significance to the measurement of flow velocity in the later stage of vacuum chamber.
2019 Vol. 40 (2): 278-284 [Abstract] ( 404 ) HTML (1 KB)  PDF  (0 KB)  ( 169 )
285 Image Reconstruction for Electrical Capacitance Tomography Based on Wavelet Fusion
ZHANG Li-feng,ZHOU Lei
DOI: 10.3969/j.issn.1000-1158.2019.02.18
An image data fusion algorithm based on wavelet transform was proposed to improve the accuracy of reconstructed images. First, reconstructed images were obtained using conjugate gradient least square algorithm and Landweber iterative algorithm, respectively. Secondly, reconstructed images were decomposed by wavelet. After that, the approximate component was processed according to the weighted average fusion rule. The detail component was processed according to the maximum fusion rule of absolute value. Finally, the new reconstructed images were obtained by wavelet reconstruction. Simulation and experimental results showed that the reconstructed images with higher accuracy can be obtained after fusion and the artefacts were decreased obviously.
2019 Vol. 40 (2): 285-288 [Abstract] ( 374 ) HTML (1 KB)  PDF  (0 KB)  ( 188 )
289 Effects of Sample Tilt on Berkovich Nanoindentation Test of Fused Silica
ZHU Guang-yu,DONG Xiang-yu,GAO Cheng-hui,LIU Ming
DOI: 10.3969/j.issn.1000-1158.2019.02.19
Berkovich nanoindentation experiments on a fused silica sample with different tilt angles were carried out. The indentation results show that the tilt of the sample affects the shape of the loading curves. The maximum indentation depth, residual depth and contact depth gradually decrease with the increase of the tilt angle of the specimen at the same indentation load, but the unloading curves are not affected, and they remain parallel to each other, the fitting parameter m of the unloading curves and the value of contact stiffness remain constant regardless of the inclination of the sample. In addition, it is found that the sample tilt will lead to smaller indentation projected contact area, which will make the hardness and elastic modulus larger.
2019 Vol. 40 (2): 289-294 [Abstract] ( 569 ) HTML (1 KB)  PDF  (0 KB)  ( 164 )
295 Error Analysis of Six-axis Force/Torque Sensors Static Calibration System
FU Li-yue,SONG Ai-guo
DOI: 10.3969/j.issn.1000-1158.2019.02.20
The composition of the six-axis force/torque(F/T) sensors static calibration system is introduced. The error sources of the system are analyzed, and the comprehensive error model of the system is built. At the end, the measures to reduce error and improve accuracy are put forward. The results show that, the calibration systems errors mainly stem from direction deviation of loading force, and the higher precision orientation calibration devices should be used to diminish loading errors.In addition, the comprehensive error model of the system demonstrates that the full-scale error of the MZ channel is 2.48%, and the other channels are below 2%.
2019 Vol. 40 (2): 295-299 [Abstract] ( 469 ) HTML (1 KB)  PDF  (0 KB)  ( 194 )
300 Gear Fault Identification Based on Torsional Vibration Analysis Method
ZHANG Hui,FENG Hao,DING Li-jun,ZHAO Hao
DOI: 10.3969/j.issn.1000-1158.2019.02.21
A new method to measure the torsional vibration of gear shaft is proposed, though analyzing and studying the mathematical model and typical faults of gear, the superiority of torsional vibration analysis in fault diagnosis of gear system is theoretically demonstrated. To verify the correctness of theoretical analysis, a gear transmission system is set up to detect the torsional vibration signals of different axes under various operating states of the gear system by the permanent magnet rotary (angular) acceleration sensor. Then, the torsional vibration signals of the gear transmission system shaft and the vibration signal of the platform is decomposed by wavelet packet, and the energy of each node is extracted as the eigenvector. Finally, the fault identification is carried out with support vector machine (SVM) with radial basis function (RBF) as kernel function. The experimental result shows that the torsional vibration signal on the shaft is superior to the diagnostic results of the platform vibration signal in fault diagnosis of gear system.
2019 Vol. 40 (2): 300-305 [Abstract] ( 413 ) HTML (1 KB)  PDF  (0 KB)  ( 173 )
306 Three Dimensional Chaotic Weak Signal Detection System with cos Function and its Circuit Implementation
LIU Jian-ming
DOI: 10.3969/j.issn.1000-1158.2019.02.22
The output wave changes between periodic and chaotic state of the variable in the two dimensional Duffing chaotic weak signal detection system were analysed. A new rule to generate the three dimensional chaotic weak signal detection system was discoveried. Making the three-dimensional Liu-cos chaotic weak signal detection system generated by above the rule as one of the four detection systems for an example, the wide convergence of the output signals of the three-dimensional chaotic weak signal detection system generated by the rule was verified by using the Fourier transform theoretical. The problems for the signal can not be detection in the wide area and can not be convergence by the two dimensional Duffing chaotic weak signal detection system were solved. The experiments in air showed that the low-frequency acoustic interference can be overcome by the new designed three-dimensional Liu-cos chaotic weak signal detection circuit. The detection performances of desigened three-dimensional Liu-cos chaotic weak signal detection circuit are better than the two dimensional Duffing circuit as well as the new designed Duffing and Filter circuits. The experiments in water showed that the high frequency acoustic interference can be overcome and the distorted acoustic signal can be detected by the three-dimensional Liu-cos chaotic weak signal detection circuit.
2019 Vol. 40 (2): 306-314 [Abstract] ( 360 ) HTML (1 KB)  PDF  (0 KB)  ( 196 )
315 Design of Zero-crossing Demodulation System for Measurement of Underwater Acoustic Pressure by Optical Method
WANG Min,YANG Ping,HE Long-biao,FENG Xiu-juan,YANG Jia-li,ZHANG Yue
DOI: 10.3969/j.issn.1000-1158.2019.02.23
Optical heterodyne interferometry is the mainly recommended technique for the next generation of underwater acoustic standards. The output Doppler signal of the optical interferometer should be demodulated by proper demodulation method, which will directly affect the acoustic particle velocity and pressure. To obtain the accurate reconstruction of underwater acoustic pressure by optical method, a zero-crossing demodulation method is introduced and an on-line demodulation system is designed. This system uses two orthogonal signals generated by function generator to simulate the outputs of photodiodes. A differential amplifier combines the two signals into one, which is recorded by an oscilloscope. Then the data are read and processed by a program containing the zero-crossing demodulation method to extract the acoustic particle velocity. Experiment results demonstrate the validation of the demodulation method and system. The designed zero-crossing demodulation system could be applied to the reconstruction of underwater acoustic pressure using optical heterodyne interferometry directly.
2019 Vol. 40 (2): 315-318 [Abstract] ( 387 ) HTML (1 KB)  PDF  (0 KB)  ( 163 )
319 Differential Measurement of Sine Wave Voltage and Multi-period Strategy
LU Zu-liang,YANG Yan,HUANG Lu,WANG Lei
DOI: 10.3969/j.issn.1000-1158.2019.02.24
The concept of piecewise sampling is applied to differential measurement of sine wave voltage. The multi-period strategy is adopted for frequency expansion of sinusoidal voltage under measurement. The experiments demonstrate practical process of these measurements and verify feasibility of the proposed approaches. The characteristic of differential measurement based on staircase waveform is analyzed. For meeting this characteristic a novel concept termed as “limiting amplitude piecewise sampling” is proposed, and the corresponding approach is presented. Based on this approach a suggestion is consequently provided to improve accuracy of the AC quantum voltage standard from level of 10-7 to 10-8. Its principle and detailed method are presented and the necessary conditions are mentioned.
2019 Vol. 40 (2): 319-328 [Abstract] ( 417 ) HTML (1 KB)  PDF  (0 KB)  ( 191 )
329 Study on Millimeter Wave Power Standard Devices
ZHONG Qing,YUAN Wen-ze,SHI Yan-ping,WANG Xue-shen,ZHOU Zhe-hai,LI Jin-jin
DOI: 10.3969/j.issn.1000-1158.2019.02.25
The standard devices for the WR-6 power standard were designed and fabricated. The micro-fabrication process was studied. The Pt film for temperature sensors was fabricated and the thermal annealing process was researched. After a annealing process at 250 ℃, the temperature coefficient of resistance (TCR) of the Pt film was 2.4×10-3/K and the relative stability was 2.4×10-6. The reflectivity of the device was below -23 dB for 110～170 GHz. The sensitivity for the DC power was 0.83 mΩ/mW.
2019 Vol. 40 (2): 329-332 [Abstract] ( 369 ) HTML (1 KB)  PDF  (0 KB)  ( 177 )
333 The Measurement of Synchrotron Radiation Single-energy X-ray Mass-attenuation Coefficient of Air
DU Hai-yan,LI Fan,WU Jin-jie,WANG Pei-wei,LAI Wan-chang,WANG Ji,ZHAO Yi-dong
DOI: 10.3969/j.issn.1000-1158.2019.02.26
Tree methods to measure the mass-attenuation coefficient of air for X-rays were introduced, which induding moving distance,vacuum and EGSnrc Monte Carlo simulation. Calculation formula of air mass thickness changed in vacuum tube after evacuated was given and influence of Be window on vacuum tube to experiment was analyzed by simulation.The results of moving distance and vacuum method have a little difference and rationality of vacuum method experiment was verified.The deviation of the results between EGSnrc Monte Carlo simulation and NIST standard database is 0.01% for 6keV and 0.26% for 20 keV X-rays respectively.
2019 Vol. 40 (2): 333-336 [Abstract] ( 445 ) HTML (1 KB)  PDF  (0 KB)  ( 181 )
337 Uncertainty Evaluation for the Determination of the Retention Ratio of the Ultrafiltration Membrane by BSA-67000
WANG Xu-liang,ZHAO Jing-hong,LI Zong-yu,HAO Jun,PAN Xian-hui
DOI: 10.3969/j.issn.1000-1158.2019.02.27
Retention performance is the most important performance indicator of ultrafiltration membrane performance, including two technical parameters which are molecular weight cut off and retention.Based on GB/T 32360—2015 "Test Methods for Ultrafiltration Membrane", according to the JJF 1059—2012 "Evaluation and Expression of Uncertainty in Measurement", BSA-67000 was choosed as standard substance, evaluation mathematical model of uncertainty of retention test results was established to analyze the sources of uncertainty, and the retention test results were evaluated.The results indicated that the polydispersity coefficient(Mw /(Mn) of BSA-67000 is 1.101 and GPC spectrum showed a single peak form, in line with PEG clear structure, molecular weight distribution narrow features, which fully meet the testing needs.The results were evaluated uncertainty.It showed that expanded uncertainty is 7.86%, when coverage factor is k=2 and level of confidence is 95%.Uncertainty of the measurement results were mainly from the removing the test sample, repeatability and spectrophotometric determination of BSA-67000.
2019 Vol. 40 (2): 337-342 [Abstract] ( 318 ) HTML (1 KB)  PDF  (0 KB)  ( 179 )
343 Research on a Novel Calculation Method of Regional Vehicle Emission
HAN Bo,JIANG Yang-hai,GAO Kui-he,BIAN Xu,WU Jing,ZHANG Huan
DOI: 10.3969/j.issn.1000-1158.2019.02.28
A novel vehicle emission calculation model named Regional Vehicle Emission Model (RVEM) was proposed based on vehicle emission detection system and database in China, which could calculate regional vehicle emission factor without considering the corrections of environmental parameters influence, for which uncertainties of model caused by corrections of environmental parameters influence could be reduced. Then, the theory, structure and the process of emission parameters calculation were introduced in detail, and it was proved that corrections caused by environmental parameters influence but not the vehicle utilized condition needn’t be consider, and then the process of average speed correction parameter calculation was introduced. Based on the proposed RVEM emission calculation model, the vehicle emission factors of car and micro-bus in Shenyang were calculated and compared with the results of the results of COPERT-V model, which not only prove the superiority of RVEM, but also prove that the per capita vehicle emission factors of car was higher than the one of micro-bus.
2019 Vol. 40 (2): 343-346 [Abstract] ( 395 ) HTML (1 KB)  PDF  (0 KB)  ( 174 )
347 The Further Discussion of the Range Method in the Type AEvaluation of Sstandard Uncertainty
CHEN Ling-feng
DOI: 10.3969/j.issn.1000-1158.2019.02.29
One of the differences between the JJF 1059.1—2012《Evaluation and Expression of Uncertainty in Measurement》 and the GUM is the introduction of the range method in the type A evaluation of standard uncertainty.Under the assumption of normal distribution and uniform distribution,the range statistic and the range coefficient can be derived from the distribution density function of the sample range.Analysis reveals that although the range estimation of the population standard deviation is unbiased, the range estimation of the population variance is biased larger.As the result,the combined standard uncertainty of the measurement result is biased larger.On the other hand, JJF1059.1 only lists the range coefficients for normal distribution,they cannot be applied in all circumstances.As a comparison,whatever the population distribution, the estimation of the population variance based on the Bessel formula is always unbiased, thus will not bring theoretical error into the calculation of the combined standard uncertainty of the measurement result.Since the range method suffering with the principle error in mathematical statistics and the restriction on applicability, it should be prudently used in the type A evaluation of standard uncertainty.
2019 Vol. 40 (2): 347-352 [Abstract] ( 553 ) HTML (1 KB)  PDF  (0 KB)  ( 196 )
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