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2016 Vol. 37, No. 4
Published: 2016-07-22
 
337 Optimization Design Method for Electromagnetic Focusing Micro-structured Metallic-film Multi-annular Plates
LIU Tao,YANG Shu-ming,JIANG Zhuang-de
DOI: 10.3969/j.issn.1000-1158.2016.04.01
Micro-structured metallic-film multi-annular plate (MAP) is one kind of novel micro-/nanophotonic element, which can be applied in the fields of super-resolution optical focusing, nanoscopic imaging, and precision engineering measurement. A versatile, fast, vectorial optimization design method for MAP is described for modulating far-field super-resolution focusing spots and ultra-thin optical needles. It is applicable for a variety of vector beams such as linearly, circularly, and radially polarized beams. Rigorous electromagnetic validation method for MAP is established based on the three-dimensional finite-difference time-domain method, which accurately models the scattering process of light propagating within micro-structured metallic annular grooves. For light wavelengths ranging from deep ultra-violet to visible, an empirical selection rule of the metallic coating film for MAP is the aluminum film at a thickness within λ/10～λ/6.
2016 Vol. 37 (4): 337-341 [Abstract] ( 667 ) HTML (1 KB)  PDF (2492 KB)  ( 577 )
342 Analysis and Application on Characteristic of Twisted High Birefringence Fiber Grating
CAI Lu-lu,WAN Yu-liang,WU-Fei
DOI: 10.3969/j.issn.1000-1158.2016.04.02
Through analysis on the characteristic of twisted high birefringence fiber grating, a novel torsion sensor which can be embeded in the engineering material is proposed. Based on the coupled mode theory and thecharacteristic of twisted high birefringence fiber, the mathematical model of twisted high birefringence fiber grating transmission light is established and the spectral characteristics is analyzed, the simulation results show that the reflective spectra of twisted high birefringence fiber grating does not have the direction, and is only related to the torsion angle size.When the twist angle changes from 0 to 360°, the two peak wavelength of high birefringence fiber grating are resulting in drift, light of x direction moved to the short wavelength direction, light of y direction moved towards long wavelength, and the reflection spectrum peak decreases gradually, through combining the prior to the coupled mode theory with the reverse coupled mode theory, analyzing and simulating,the conclusion that x and y directions wave peak variation are drew, and the center wavelength changes corresponding amount, finally make a validated through experimental data of the relationship between changes of parameters of high birefringence fiber grating and torsional angle.
2016 Vol. 37 (4): 342-346 [Abstract] ( 901 ) HTML (1 KB)  PDF (399 KB)  ( 644 )
347 Bilateral Comparison of Spectral Irradiance between NIM and VNIIOFI
DAI Cai-hong,WU Zhi-feng,WANG Yan-fei,LIN Yan-dong,Boris Khlevnoy
DOI: 10.3969/j.issn.1000-1158.2016.04.03
With the new spectral irradiance measurement facility based on blackbody BB3500M of NIM (National Institute of Metrology), a bilateral spectral irradiance comparison was carried out between NIM and VNIIOFI (All Russian Research Institute for Optical and Physical Measurements) in the spectral wavelength from 250 nm to 2500 nm in the period from December 2014 to January 2015. The temperature measurement of the high temperature blackbodies were traced to the Pt-C and Re-C fixed point blackbodies and checked against the WC-C fixed-point blackbody for the two institutes respectively. The consistency of the temperature at 3021K is better than 70mK. The comparison result shows that the average relative deviation of spectral irradiance at the 44 wavelengths is 0.45%. The consistency is better than 0.9% except the maximum deviation 1.1% at the wavelength of 2000nm. The spectral irradiance units measured by NIM and VNIIOFI in this comparison are in agreement within the combined standard uncertainties of the laboratories over the wavelength range compared.
2016 Vol. 37 (4): 347-351 [Abstract] ( 1034 ) HTML (1 KB)  PDF (524 KB)  ( 530 )
352 Image Restoration Research Based on Quantum Bit Plane Code Algorithm
Li-fang,TIAN Li SUN
DOI: 10.3969/j.issn.1000-1158.2016.04.04
In order to improve image reconstruction quality, quantum bit plane code algorithm is proposed.Firstly, image pixel gray was coded, and then intermediate segment gray level filter matrix was obtained. Secondly, quantum bit is transformed Walsh-Hadamard, input image pixel is decomposed low and high frequency part. Each positive and negative coefficient matrix was scanned,bit sign was inserted between positive and negative coefficient bit plane code stream. Finally the process is given. Simulation results show this algorithm reconstruction effect is clear, index of image signal to noise tate is largest and RMSE is close 0.
2016 Vol. 37 (4): 352-355 [Abstract] ( 774 ) HTML (1 KB)  PDF (532 KB)  ( 478 )
356 Aerial Image Denoising Method Based on Pixel Peer Groups
YANG Cheng-shun,HUANG Ying,HUANG Huai,HUANG Xiao-ning
DOI: 10.3969/j.issn.1000-1158.2016.04.05
Due to the impact of shooting environment, such as light and fuselage vibration, aerial image is often mixed with Gauss noise and impulse noise. Aiming at this characteristics, a new image denoising method based on the pixel peer groups is proposed, which combining the improved median filtering and Wiener filtering. Firstly, the image is divided into a number of pixel peer groups. Then, according to the characteristics of each pixel peer groups, the median filtering or Wiener filtering to filter the image noise was selected. Finally, the simulation experiment is carried out by the use of aerial insulator image. And the experimental results of this paper are compared with the denoising effect of the use of the median filter and the use of Wiener filtering along. The experimental results show that the method in dealing with aerial image noise, which mixed with Gaussian noise and impulse noise, has a good denoising effect.
2016 Vol. 37 (4): 356-359 [Abstract] ( 643 ) HTML (1 KB)  PDF (914 KB)  ( 535 )
360 The development of large scale measurement and control network for large space laser ranging
DOI: 10.3969/j.issn.1000-1158.2016.04.06
In order to solve some problems of large measurement tasks, huge measuring points, huge data and the data processing difficulty in the process of large-scale laser ranging, the development scheme of measuring network of the large space laser ranging is designed. The solution of combining the cloud computing platform with large measurement and control network is proposed. The instruments which have the function of serial communication can work together to get more powerful ability of measurement, to achieve a variety of wireless network integration, to solve the problem of storage and data processing. The experimental results show that the memory is set to 2G, and the virtual hard disk is set to 500G. When the data storage is more than 500G, the measurement data can be stored in the cloud platform. The problem of insufficient memory do not occur when the data amount is over 2G. The combination of Matlab and virtual machine can accomplish complex tasks, and the key points coordinate can be solved quickly and accurately.
2016 Vol. 37 (4): 360-365 [Abstract] ( 577 ) HTML (1 KB)  PDF (2289 KB)  ( 989 )
366 Study on the Angle Sensor of Magnetic Fluid
SU Shu-qiang,LI De-cai
DOI: 10.3969/j.issn.1000-1158.2016.04.07
According to the character that permanent magnet can be suspended in a magnetic fluid, a new type of one-dimensional angle sensor structure is put forward. The operation principle of the sensor is given. A sensor prototype is designed to test the magnetic repulsion curve of permanent magnet by experimental method, based on it the main structure parameters and characteristic parameters of the sensor are determined and sensitivity expressions of its dip angle are obtained. Detection circuit and switching circuit of moving parts in sensor are designed. Experiments show that the output voltage and the inclination is linear when the dip angle is between -18° and 18°,and its resolution is 0.04°. The output voltage is nonlinear with the inclination angle when the dip angle is between 18° and 90° or -18° and -90°, and its resolution is gradually reduced. The structure of sensor is simple, has no wear parts, and it provides a new way to measure the angle of inclination.
2016 Vol. 37 (4): 366-370 [Abstract] ( 700 ) HTML (1 KB)  PDF (1369 KB)  ( 738 )
371 Algorithm of Sub-pixel Edge Detection based on Gauss Integral Curve Fitting
DUAN Zhen-yun,WANG Ning,ZHAO Wen-hui,ZHAO Wen-zhen
DOI: 10.3969/j.issn.1000-1158.2016.04.08
Aiming at the low accuracy in localization and sensitivity to noise in traditional edge detection algorithm, an algorithm of sub-pixel edge detection based on Gauss integral curve fitting is proposed. The gray value of discrete points on pixel edge normal section line is calculated with surface interpolation, and fitting Gauss integral curve, achieving accurate location of sub-pixel edge by searching the mean point of Gauss integral curve. Experiment with the gauge block line edge, and comparing with the existed sub-pixel edge detection algorithm, the experiment show that algorithm of sub-pixel edge detection based on Gauss integral curve fitting has high location accuracy, and can reach 1 μm, it also has high reliability and speed, and can be used for high precision measurement.
2016 Vol. 37 (4): 371-374 [Abstract] ( 1080 ) HTML (1 KB)  PDF (2514 KB)  ( 1476 )
375 Study on Filters for Measuring Waviness Parameters on Metallic Sheet Surface
JIANG Guang-rui,ZHANG Hao,LIU Li-bin,LI Chun-guang
DOI: 10.3969/j.issn.1000-1158.2016.04.09
Transmission characteristics of three different filters including 2RC filter, Gaussian filter and an exponential filter for measuring waviness parameters on metallic sheet surface were analyzed. Then, spectrums of waviness profiles calculated by different filters and that of primary profile were compared. Finally, waviness parameters on sheet surface through different filters were figured out. Although no amplitude oscillation exist for all of the three filters, differences among amplitude attenuation rate were noticed. At the cut-off wavelength, amplitude of the Gaussian filter and the exponential filter decrease a half and that of the 2RC decreases a quarter. For phase characteristic, the Gaussian filter and the exponential filter belong to phase correct filters and the 2RC filter belong to no phase correct filter whose phase shift about 1.05 at the cut-off wavelength. Furthermore, it could be found that the transmission characteristics of the Gaussian filter are exactly same as that of the exponential filter. Moreover, the waviness parameter measured by the 2RC filter is bigger 0.1μm than that measured by the Gaussian filter. Results show that all the three filters could not exactly suppress component beyond scope defined by cut-off wavelengths and remain component between the scope.
2016 Vol. 37 (4): 375-379 [Abstract] ( 720 ) HTML (1 KB)  PDF (7591 KB)  ( 359 )
380 Real-time Recession Measurement of Stagnation Thermal Protection Materials by Projective Recession Measurement Method
ZHANG Zhi,OU Dong-bin,GAO He,CHEN Lian-zhong
DOI: 10.3969/j.issn.1000-1158.2016.04.10
To measure the line recession of thermal protection materials on stagnation aero of hypersonic vehicle, an optical method of projective recession measurement (PRM) is described. The line recession was obtained by calibrating the proportional coefficient between camera and model, collecting ablative video of model and image processing. The method was applied to measure 4 materials under two states, the frequency of the measurement is 25Hz, and the error of the measuring results is less than 0.16mm. The measuring results can be applied to ablation analysis.
2016 Vol. 37 (4): 380-383 [Abstract] ( 793 ) HTML (1 KB)  PDF (956 KB)  ( 586 )
384 Research Progress of Primary Heat Capacity Standard for Medium Temperature
LI Jia,WANG Can,WANG Hai-feng,SUN Guo-hua
DOI: 10.3969/j.issn.1000-1158.2016.04.11
The primary heat capacity standard for medium temperature is employed for the traceability of the specific heat capacity, phase transition temperature and enthalpy. The device mainly adopts the adiabatic calorimetric method, which makes the calorific value traceable to SI units. Firstly, the research significance and the principle of primary heat capacity standard is introduced, and then the progress on the research in the field is demonstrated. Finally new design and scheme of primary heat capacity standard based on this work are put forward.
2016 Vol. 37 (4): 384-389 [Abstract] ( 758 ) HTML (1 KB)  PDF (3788 KB)  ( 793 )
390 The Design of High-precision Mechanical Vibration Measurement Instrument Based on Amplitude Amplification
YANG Ji-senZHANG Tian-heng,JIANG Hong-qing,ZHANG Xing-hong
DOI: 10.3969/j.issn.1000-1158.2016.04.12
In order to detect the frequency of weak vibration, a method to measure the mechanical vibration is proposed with amplitude amplification, while a mechanical vibration precision measuring instrument is designed on the basis of it. When measured by the amplitude amplifying method, it means to amplify weak vibration amplitude and change it into an electrical signal by a piezoelectric sensing element, and then the signal is sampling by high speed A/D converter and FPGA hardware circuit, and time measurement can reach 0.061ns level under software interpolation subdivision algorithm, so as to realize high-precision frequency measurement.
2016 Vol. 37 (4): 390-393 [Abstract] ( 560 ) HTML (1 KB)  PDF (480 KB)  ( 742 )
394 Study on a Self Compensating Differential Torque Sensor
ZHAO Hao
DOI: 10.3969/j.issn.1000-1158.2016.04.13
A new structure differential torque sensor with compensating winding is designed. The method is to convert torsion angle produced by load torque into the angle displacement of sensor excitation winding and output winding, the excitation winding sets up pulsating flux, and the output winding are connected differentially, the output winding produces induction potential which is proportional to the angular displacement through electromagnetic coupling. The output characteristic of sensor is deduced by the magnetic circuit theorem and ampere circuital theorem, and the reasons that sensor output characteristic distortion produced by load resistance are analyzed, and the corresponding method is presented. The sensor is calibrated by torsion testing machine, the experimental results indicated the sensitivity of the sensor is 4.07 mV/(N·m), the repeatability error is about 3.17%, the non-linear error is about 2.34%, and the hysteresis error is about 0.55%.
2016 Vol. 37 (4): 394-397 [Abstract] ( 679 ) HTML (1 KB)  PDF (349 KB)  ( 658 )
398 Research on The Analysis Method of Vibro- acoustic Modulation Signal Based on EMD and SVD
ZHENG Hui-feng,YU Sang-sang,WANG Yue-bing,FANG Piao-piao,WANG Cheng,TANG Ting-hao
DOI: 10.3969/j.issn.1000-1158.2016.04.14
In order to solve the problem that due to the influence caused by strong noises the characteristic signal could not be extracted effectively, the analysis method of vibro-acoustic modulation signal based on empirical mode decomposition and singular value decomposition is proposed. The signal is decomposed by empirical mode decomposition for selecting the imf component, then singular value decomposition is conducted on the imf component for obtaining the nonlinear characteristic signal. Kolmogorov entropy of the characteristic signal was calculated. Secondly, the algorithm was applied to detect the actual carbon fiber composites. Finally, Kolmogorov entropy is used to assess damages. The method is successfully extracted characteristic signal, achieving diagnosis and quantitative assessment of the damages and the algorithm has strong adaptive capacity.
2016 Vol. 37 (4): 398-401 [Abstract] ( 725 ) HTML (1 KB)  PDF (379 KB)  ( 883 )
402 Research of the Fault Diagnosis for Air Brake Systems Based on a Analyical Model
LU Yi,ZHU Qiang,XIA Wen-jie,GUO Bin
DOI: 10.3969/j.issn.1000-1158.2016.04.15
Aimed at the problem of leak for air brake systems, based on an analyical model, a method for leak fault diagnostic of air brake systems is presented. Through analysis of the working condition of the brake valve and the brake chamber in the air brake system, a model of the brake chamber steady state pressure characteristic for the passenger car air brake system was built. This model was built on the premise that the air brake system without any fault and this model could predict transient pressure in the brake chamber. Then, a simulative test rig for the vehicle air brake system was built. The brake performance experiments by this simulative test rig and measure the brake chamber steady state pressure during the experiments will be conducted. The data measured in experiments were compared with the predictions of the model. Test shows that the method is effectively to diagnosis the leak fault for air brakes.
2016 Vol. 37 (4): 402-405 [Abstract] ( 581 ) HTML (1 KB)  PDF (335 KB)  ( 927 )
406 Fault Feature Extraction of Rolling Bearing Incipient Fault Based on Improved Singular Value Decomposition and EMD
MENG Zong,GU Wei-ming,HU Meng,XIONG Jing-ming
DOI: 10.3969/j.issn.1000-1158.2016.04.16
To extract fault characteristics from the original signal is hard. For this reason, a novel integrated of incipient fault diagnosis method is presented based on the principle of the improved singular value decomposition(SVD) and empirical mode decomposition(EMD). Firstly, based on multi-resolution singular value decomposition, the original signal is decomposed into approximation and detail signals with different resolution. Then the noise in approximation signal is eliminated by using difference spectrum of singular value. The signal after de-noising is decomposed by EMD and a group of Intrinsic Mode Functions (IMF) is obtained. The IMFs were demodulated with Hilbert transform, and envelope spectrum at each band was obtained, through these procedures the faint feature information can be extracted. The effectiveness of this method is confirmed by the experiment of rolling bearing inner race incipient fault.
2016 Vol. 37 (4): 406-410 [Abstract] ( 622 ) HTML (1 KB)  PDF (1581 KB)  ( 1085 )
411 Uncertainty Evaluation for the Measurement of Sound Absorbing Coefficient in Reverberation Room
QIAN Zhong-chang,FU Yun-xia,YU Pei-ying,DENG Zheng,CHEN Wen-wang
DOI: 10.3969/j.issn.1000-1158.2016.04.17
Based on the measurement of sound absorption coefficient in reverberation room, the source of the uncertainty of measurement result is identified. Uncertainty components are further analyzed, results showed that the measurement uncertainty of absorption coefficient is mainly introduced by measurement of reverberation time, the volume of reverberation room, size of specimen and velocity of sound measurement have little contribution to the uncertainty of sound absorption coefficient measurement. The uncertainty of reverberation time measurement depends on the diffusion degree of room sound field , the contribution of measuring device is small.
2016 Vol. 37 (4): 411-414 [Abstract] ( 897 ) HTML (1 KB)  PDF (481 KB)  ( 806 )
415 Research and Uncertainty Evaluation for Energy Efficiency Testing System of Electric Fans
CHENG Yin-bao,CHEN Xiao-huai,ZHANG Xiao-jun,LI Hong-li,WANG Han-bin
DOI: 10.3969/j.issn.1000-1158.2016.04.18
The theory of energy efficiency testing system of electric fans was researched in order to obtain the accurate and credible measuring data. Moreover, the method of air volume test was described mainly. System control, data collection, storage and translation were achieved by computer, the computer and programmable logic controller are linked by communication interface RS232. The methods of air volume and energy efficiency measurement were given clearly, and the uncertainty of measurement result was evaluated.
2016 Vol. 37 (4): 415-418 [Abstract] ( 733 ) HTML (1 KB)  PDF (317 KB)  ( 639 )
419 The Phase Difference Evaluation Based on Total Least-square Method with Partial Period Sinusoidal Waveforms
LIANG Zhi-guo
DOI: 10.3969/j.issn.1000-1158.2016.04.19
Aiming at the phase measurement problems of partial period sine wave, a novel phase difference measurement method is introduced. By using the sinusoidal curve-fit method with partial wave period, the phase difference can be attained. The courses and principles are presented in detail. Through local distortion and noise to signal ratio, and using the simulation in the condition of real measurement parameter, the measurement uncertainty of phase difference can be estimated. Finally, in the calibration of Laser Doppler Velocimeter, a comparative experiment is executed, the result shows that, in about 0.5 period sinusoidal waveform, one can get excellent phase difference in deed, the deviation between partial period and multi periods signals is only about 1°. The validity and feasibility are proved, and it must be a novel phase difference measurement method.
2016 Vol. 37 (4): 419-422 [Abstract] ( 755 ) HTML (1 KB)  PDF (1459 KB)  ( 674 )
423 An Improved Target Localization Algorithm for WSN
XUE Bo, ZHANG Lin-hua,SHEN Lin,YU Yang
DOI: 10.3969/j.issn.1000-1158.2016.04.20
Based on the target spatial domain discretion, the target localization problem is formulated as a sparsity-seeking problem which can be solved by compressed sensing(CS) technique. In order to satisfy the robust recovery condition for CS theory requirement, an orthogonalization preprocessing method called LU decomposition is utilized to make the measurement matrix obey the restricted isometry property(RIP).Meanwhile, an improved orthogonal matching pursuit(IOMP) algorithm is proposed to recover the position of target, and the weighted centroid algorithm to enhance the positioning precision was also adopted. The simulation results illustrate that the average localization error of the proposed algorithm is less than other existing algorithms.
2016 Vol. 37 (4): 423-427 [Abstract] ( 559 ) HTML (1 KB)  PDF (913 KB)  ( 674 )
428 A Novel Weighted Centroid Localization Algorithm Based on LQI
LIAO Wen-zhe,ZHENG De-zhong,MA Lei-lei
DOI: 10.3969/j.issn.1000-1158.2016.04.21
A new localization algorithm that the LQI-based ranging technology is combined with the weighted centroid localization algorithm is described. Through data analysis and comparison, the LQI has the more stability and stronger anti-interference ability than the RSSI. Using Gauss filter model to deal with the measured value of the experiments, the accuracy of the data is increased. The logarithmic ranging formula based on RSSI and LQI was established respectively. Simulation experiments using centroid localization algorithm are carried out. The results show that the improved weighted centroid localization algorithm based on LQI can further improve positioning accuracy, and achieve a good positioning effect.
2016 Vol. 37 (4): 428-432 [Abstract] ( 714 ) HTML (1 KB)  PDF (1457 KB)  ( 691 )
433 Rubidium Mass Measurement and Lifetime Evaluation of the Lamp Bulb of a Rubidium Atomic Clock
HE Sheng-guo,WANG Fang,ZHAO Feng,WU Han-hua,MEI Gang-hua
DOI: 10.3969/j.issn.1000-1158.2016.04.22
Long operation lifetime is critical important for the space rubidium atomic clock used in the GNSS satellites. The lifetime of a rubidium clock is closely related to the lifetime of rubidium spectral lamp. For the purpose to accurately evaluate the lifetime of rubidium spectral lamp, a new method to gather the rubidium metal in the lamp bulb was developed, and the accuracy of rubidium mass measurement with differential scanning calorimeter (DSC) was greatly improved by using the method. Through fitting rubidium consumption data of 7 years, a rubidium consumption model with highest precision so far for the bulbs made of Schott 8436 glass was established. According to the model, a some 130 μg of rubidium mental filling in the bulb will ensure a 50 years operation time of the bulb.
2016 Vol. 37 (4): 433-436 [Abstract] ( 735 ) HTML (1 KB)  PDF (1988 KB)  ( 960 )
437 A High Signal to Noise Ratio Physics Package with A Slotted-tube Cavity for Rubidium Atomic clock
XU Feng,HAO Qiang,WANG Peng-fei,MING Gang,MEI Gang-hua
DOI: 10.3969/j.issn.1000-1158.2016.04.23
The frequency stability of a rubidium atomic clock is determined mainly by the signal to noise ratio of the atomic frequency discrimination signal provided by the physics package. With the help of high frequency structure simulation software, a slotted-tube microwave cavity with inner-diameter of 20 mm has been designed. Analysis and measurement showed that the microwave field in the cavity is uniformly and densely distributed along the cavity axial, helpful to drive intense clock transition. Based on the cavity, a physics package with separated filter structure was designed, and filtering effect was optimized through hyperfine spectroscopy measurement with a scanning Fabry-Perot interferometer. Test showed that the physics package is of high signal to noise ratio, and can be used to built a high performance rubidium atomic clock with frequency stability of 5.0×10-13/t-1/2.
2016 Vol. 37 (4): 437-440 [Abstract] ( 722 ) HTML (1 KB)  PDF (3485 KB)  ( 851 )
441 The NIM-IAEA Bilateral Comparison on the Air Kerma and Absorbed Dose to Water of 60Co γ Radiation
JIN Sun-jun,WANG Zhi-peng,WANG Kun,YANG Xiao-yuan,HUANG Jin-feng, FAN Yao-dong,CHANG Xue,ZHANG Jian
DOI: 10.3969/j.issn.1000-1158.2016.04.24
In the 60Coγ primary standard laboratory at National Institute of Metrology(NIM), the primary standard values of the air keama and absorbed dose to water of 60Coγ radiation were disseminated to the FC65-G-2869 chamber from International Atomic Energy Agency(IAEA), and then the calibration factors were obtained.The calibration factors of the two physical quantities given by NIM were compared with the original calibration factors from IAEA.For the NIM calibration factors of the air kerma and absorbed dose to water of 60Coγ radiation to the IAEA FC65-G-2869 chamber, the discrepancies are 0.5% and 0.1% respectively, relative to the corresponding IAEA results.The comparison results are considered to be acceptable.This work is the preliminary preparation for NIM to participate in the ongoing Bureau International des Poids et Mesures(BIPM) key comparisons for the air kerma and absorbed dose to water of 60Coγ radiation.
2016 Vol. 37 (4): 441-443 [Abstract] ( 593 ) HTML (1 KB)  PDF (493 KB)  ( 679 )
444 Uncertainty Analysis for Determination of Air Kerma in γ-ray Beam
LI De-hong,CHENG Jian-bo,WANG Pei-wei,LI Xing-dong,GUO Bin
DOI: 10.3969/j.issn.1000-1158.2016.04.25
Based on the Bragg-Gray cavity theory of measurements of air kerma for gamma ray, the air kerma rate is measured by using graphite cavity ionization chamber, and the mathematical model of measurement is established. The effect of influence quantities and its correction are taken into account during the process of uncertainty analysis for the measurement of air kerma. The correction factors and its uncertainty are gotten by using the methods of measurement and Monte Carlo simulation. The expanded uncertainty of gamma ray air kerma is about 0.5%, and that the mainly contribution of the uncertainty of gamma ray air kerma are come from the uncertainty of wall correction and average ionization power, so it is necessary to carry out the corresponding research, in order to improve the uncertainty level of the air kerma rate measurement.
2016 Vol. 37 (4): 444-447 [Abstract] ( 782 ) HTML (1 KB)  PDF (856 KB)  ( 844 )
448 Research on Aerosol Dilution Method in the Calibration Process of Laser Paticle Counter
HUANG Zhi-huang,LIU Jun-jie,GUO Kai
DOI: 10.3969/j.issn.1000-1158.2016.04.26
In order to solve the traceability problem that the laser particle counter can not be implemented by condensation nucleus counter based on direct comparing method, according to the principle of Bernoulli gas flow and the calculation method of aerosol dilution ratio, the dilution process of aerosol is analysed. As the increase of added gas flow,it has a problem that the pressure inside the dilution chamber is not constant. A new method of aerosol dilution to meet the traceability issues of laser particle counter is proposed. The results show that the new method could settle the interference matter of aerosol outlet flow caused by make-up gas, and keep a better uniformity among 0~90 times particles dilution ratio of different diameter in high concentration of aerosol. The max relative error of the measured data and the theoretical calculation is no more than 4.4%.
2016 Vol. 37 (4): 448-451 [Abstract] ( 1059 ) HTML (1 KB)  PDF (644 KB)  ( 704 )
452 Application of Adaptive Monte Carlo Method on Measurement Uncertainty Evaluation
FANG Xing-hua,SONG Ming-shun,GU Long-fang,CHEN Yi-hua
DOI: 10.3969/j.issn.1000-1158.2016.04.27
GUM Sup.1 is concerned with the propagation of distribution through a mathematical model of measurement as a basis for evaluation of uncertainty of measurement. It introduced the principles and the detail processes of Adaptive Monte Carlo method to carry out the propagation of distribution. Then two measurement models were provided, including linear model and non-linear model, to validate the applicative of Adaptive Monte Carlo method. And it proved that both models reached the reasonable evaluation results. At the same time, some problems such as how to choose proper Monte Carlo simulation sample M and numerical tolerance δ were still need to be further researched.
2016 Vol. 37 (4): 452-456 [Abstract] ( 717 ) HTML (1 KB)  PDF (2639 KB)  ( 1253 )
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