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2016 Vol. 37, No. 2
Published: 2016-03-22
113
Research of the Atomic Force Microscope Scanning Head Based on the Qplus Technology
WANG Zhi-xin, GAO Si-tian, LI Dong-sheng,Li Qi, LI Shi, LI Wei, SHI Yu-shu
DOI: 10.3969/j.issn.1000-1158.2016.02.01
The atomic force microscope (AFM) scanning head based on the qPlus technology is preliminarily designed and assembled. The silicon cantilever sensor is replaced by quartz tuning fork type force sensor. Preamplifier circuit is designed and frequency characteristic of this scanning head is also analyzed. Finally, the experimental device for this scanning head is set up to make performance test. The test results show that the scanning head has a high sensitivity in the mode of frequency modulation. Meanwhile, the analysis of frequency characteristic indicates that the weight of tip and the bonding portion is the main factor to influence the resonant frequency of this scanning head. This research provides experiences for the design and assembly of this type scanning head and also lays a foundation for further study.
2016 Vol. 37 (2): 113-117 [
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1226
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118
An Algorithm Research for Mobile Robot Localization Based on the Improved Scale Invariant Feature Transform of Color Moment
ZHU Qi-guang,ZHANG Xing-jia,CHEN Wei-dong,CHEN Ying
DOI: 10.3969/j.issn.1000-1158.2016.02.02
The hierarchical image matching algorithm for the real-time and accuracy requirement to process image is proposed in the field of image appearance-based mobile robot localization. The improved scale invariant feature transform, based on color moment, is used for the algorithm. The algorithm is firstly performed by color moment to sort the image sequences. Following, improved scale invariant feature transform is used to match with the sorted image sequences. To improve scale invariant feature transform, the sampling-based iterative search approach is used to detect extremums, as well as the magnitude and orientation of the keypoints gradient is calculated by Sobel operator. Experimental results show that the improved scale invariant feature transform reduces the false matching rate by 9.2%, as well the time of features extraction and matching is reduced by 25.8%. The hierarchical image matching algorithm reduces the calculation cost of scale invariant feature transform by 70% and the run time by 43.3%.
2016 Vol. 37 (2): 118-122 [
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787
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123
Minimum Zone Evaluating for Sphericity Error Based on Geometry Search Approaching Method
LEI Xian-qing,GAO Zuo-bin,MA Wen-suo,DUAN Ming-de
DOI: 10.3969/j.issn.1000-1158.2016.02.03
According to geometric definition of the sphericity, a novel evaluation method which named as geometry search approaching method for sphericity error is presented. Firstly, an initial reference point is taken as a datum point and built a regular hexahedron and established an auxiliary points. Secondly, the each auxiliary points and the datum point are used as the centre of the measured sphere to calculate the radius of all measured points. And then modify the side length of the hexahedron or the position of the reference point by comparing these radius extreme differences. Finally, by repeating this process, the minimum zone containing all measurement points is obtained and the minimum zone evaluation for the measured spherical surface is implemented. The method is used to process a group of metrical data, and the results indicate that the sphericity error value from this algorithm can be reduced by 0.6μm as compared with least square method, and are consistent with the results obtained by the analytic method and evolutionary computation method. The results show that the algorithm can get not only the minimum zone solution accurately but also has good stability.
2016 Vol. 37 (2): 123-127 [
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752
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128
Study on Undecided Steps Technique of the Improved Measurement System for Phase-shifting Profilometry
ZHOU Ming-an,XU Jian-liang,FANG Xiao-fen
DOI: 10.3969/j.issn.1000-1158.2016.02.04
Phase-shifting profilometry of the improved measurement system is proposed. The proposed system makes the three constraints of the traditional phase-shifting profilometry measurement system less stringent, and reduces requirements of the structure for the system. Compared with traditional phase profile measurement technology, phase-shifting does not need to be equal, and the method can only two distorted grating images which reconstruct 3-D shape. Through theoretical analysis, the mathematical relationship between the phase and the height is given. Experiments show that on the premise of the measurement accuracy can be satisfied, the structure is less demanding for the accuracy of the system, and the improved measurement system is faster and more practical.
2016 Vol. 37 (2): 128-132 [
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696
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133
Improvement of high-speed optical scanner performance based on reuse model
LUO Ying,ZHANG Tong,LIU Lin,SONG Yun-cen,YE Yu-tang,LIU Yong
DOI: 10.3969/j.issn.1000-1158.2016.02.05
A JPEG image compression method based on FPGA and DDR II is proposed. The A3 high-speed scanner is designed and realized. The issue of mutual restraint between the hardware resource and the scanning speed in the high-speed scanner is solved. Basic principle is to build flexible, fast large amount of data storage and transmission mode while reducing the consumption of on-chip RAM through the internal and external storage type water reuse model. And using an efficient time-multiplexed data link to implement the JPEG image compression further improves the compression and transmission speed of hardware module. Theoretical analysis and experimental results show that using the A3 high-speed scanner designed with low-end FPGA chip, the speed of scanning A3 wide paper under a 300dpi resolution can reach 140 page per minute, scanning time delay is less than 1ms, peak signal noise ratio as high as 86.9dB before and after compression, and this fully meets the requirements of high-end high-speed scanners. The high-speed scanners for hardware resource requirements are greatly reduced under the implementation of the model, and this model can also be promoted to apply in other high-speed scanner with different format.
2016 Vol. 37 (2): 133-137 [
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588
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138
Advanced Encryption Standard Image Encryption Algorithm Based on Hybrid Chaotic Model
MI Zeng-zhen,ZHU Ge,ZHANG Hong-min,CONG Chao,CHENG Yao,YANG Qian
DOI: 10.3969/j.issn.1000-1158.2016.02.06
In order to improve the safety performance of the image encryption algorithm, an advanced encryption standard encryption algorithm is proposed based on hybrid chaotic system. Logistic combined with Chebyshev chaotic sequence to produce two kinds of new chaotic sequences, the first hybrid chaotic matrix was used as the advanced encryption standard round keys for pixel scrambling and the another hybrid chaotic matrix is used as S-box for position scrambling. In addition, do shift row and mixcolumn operation will be shifted to change the pixel position and realize the dynamic transform key of advanced encryption standard image encryption. Experiment shows that the algorithm possesses the features of sensitive key dependence, good scrambling effect and efficiency.
2016 Vol. 37 (2): 138-142 [
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699
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143
Measurement of Thermal Conductivity Using Transient Hot-strip Method of Constant Power
CAI Jie,SHEN Fei
DOI: 10.3969/j.issn.1000-1158.2016.02.07
Based on the traditional transient hot-bridge sensor, a new unsymmetrical model to measure thermal conductivity—the transient hot-strip method of constant power is proposed. This model insulated the heat source and the thermometer, eliminating the influence of self-heating from strips and the ambient temperature variations. By measuring the voltage change verse time, the thermal conductivity of the material can be obtained accurately. With this method, the corresponding heat sensor is designed, and the auto measurement platform of experimental system based on LabVIEW is established. By using this platform, the thermal conductivities of several normal materials are tested. Satisfactory consistent between the values obtained here and the reference values, the relative deviation is about 3%, and the validity of the theoretical model is verified.
2016 Vol. 37 (2): 143-147 [
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708
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148
Research on System Time Character of Valve in pVTt Gas Flow Facility
GONG Lei,GONG Zhong-zi,CHEN Feng-hua,PAN Qin,WU Li
DOI: 10.3969/j.issn.1000-1158.2016.02.08
Through the analysis of the mechanism and measuring method of system time of valve in pVTt gas flow facility, the simplified algorithm is derived to calculate the time difference of the valve open/close process. The relationship between the factors of time difference of the valve open/close process and valve structure, sonic nozzle flow are also analyzed, and the impact of additional mass correction on time difference of the valve open/close process is obtained.
2016 Vol. 37 (2): 148-150 [
Abstract
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673
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151
The Moment-arm System of 1mN·m to 1 N·m Torque Standard Machine
ZHANG Zhimin,LI Tao,ZHANG Yue,JI Hong-lei,MENG Feng
DOI: 10.3969/j.issn.1000-1158.2016.02.09
Guide::
null
A high accuracy 1 mN·m to 1 N·m torque standard machine is newly developed at National Institute of Metrology (NIM). For 1 N·m torque standard machine, the moment-arm system is the key component of the machine, the structure and material of moment-arm concern the accuracy of moment-arm length and affect the technical performance of the machine. The structure design, the material selection and the manufacture and measurement of the moment-arm are introduced, the automatic limit protection component and the software emulation on stress and deformation of the moment-arm are described. The uncertainty of the moment-arm length is evaluated to be 4.2×10
-6
(k=2), the moment-arm fully meets the requirements of technical performance of 1 N·m torque standard machine.
2016 Vol. 37 (2): 151-154 [
Abstract
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770
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155
Study on the Technology of Standard Force Generating Device with Double Levers and Changeable Lever Ratio
ZHANG Xue-cheng,TANG Chun-qian
DOI: 10.3969/j.issn.1000-1158.2016.02.10
A loading way and a device with double levers and a changeable lever ratio is introduced. The device is composed of two levers, one main lever and one ministrant lever. According to the changeable lever ratio principle, force is applied by the main lever while the ministrant lever maintain the initial balance of the entire system. The changeable lever ratio principle indicates that the lever ratio alters via an individual weight moving alone the lever arm. The force applies to the specimen because of the lever ratio alternation. That is, the variational force is applied through controlling the position of the weight. The system restores balance after loading. With the loading method mentioned above, the operation of such device would be simple and the balance state is adjusted naturally at zero. The system force control is realized by precise displacement change, such method results to much wider force value and fewer errors. The frequency of weight move decides the speed of force application, therefore, this device enhances the loading efficiency. The basic principle of the machine is presented in details and the errors analyzed as well. Furthermore, an experiment to a 1MN force standard machine which applies such techniques was conducted. Data and test result are also included . The force value accuracy class 0.01 is achievable according to the test result.
2016 Vol. 37 (2): 155-158 [
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741
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159
The Analysis on Pressure Compensation Performance of Corrugated Diaphragm which is Used as Pressure Compensation Element for Underwater Instruments
LIU Zheng-shi,LIU Huan-jin,CHEN En-wei,LU Yi-min,WANG Yong
DOI: 10.3969/j.issn.1000-1158.2016.02.11
The compensation mechanism of the corrugated diaphragm used as the pressure compensation element in underwater pressure sensor is analyzed. Based on the compressibility of liquid, the method for analyzing the compensation performance of corrugated diaphragm is presented and the relationship among the work depth of sensor, the compensation volume of the corrugated diaphragm and the differential pressure between internal and external of pressure sensor is derived, and the process to calculate the differential pressure is also brought forward, which can be used to analyze and design the corrugated diaphragm used as pressure compensation element. The compensation performance of flat and corrugated diaphragm which have the same material and size is also analyzed. Results show that there is a depth threshold to measure the pressure compensation performance of the two kinds of diaphragm. When the water depth is greater than the threshold, the pressure compensation performance of corrugated diaphragm is better than that of flat diaphragm.
2016 Vol. 37 (2): 159-162 [
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793
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163
Standard Uncertainty in Torque Loader
LIU Jun
DOI: 10.3969/j.issn.1000-1158.2016.02.12
The uncertainty of torque loader vary according to the measured object, usually referred the experimental data or long-term measurement experience to estimate it. Based on analyzing the forces of torque wrench and the error sources, type B is used to evaluate standard uncertainty of torque loader, derived the formula of calculating the standard uncertainty under various vector action, changing the experimental methods and empirical methods into the quantification method, the relative uncertainty obtained in connection with the effective length of force arm of torque wrench, the length of sensor, the roughness on the surface of structure and an adaptor. The quantitative results agree well with the experimental results by PTB, it has guiding significance on design and manufacture the device for calibrating torque wrenches as well as user selects the device.
2016 Vol. 37 (2): 163-166 [
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795
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167
Instantaneous Torsional Vibration of Gear Transmission System by Direct Measurement Tests
FENG Hao,ZHAO Hao,ZHU Yao-dong,WU Xiao-yang
DOI: 10.3969/j.issn.1000-1158.2016.02.13
A new structure of magnet-electric induction torsional vibration measurement device is designed, which can directly convert the instantaneous torsional vibration of gear transmission system into the corresponding electrical signal. The mechanical structure and operation principle of this device is introduced, and the output characteristic is induced. The instantaneous torsional vibration of gear transmission system under no load、rated load and variable voltage speed control is measured directly by this device, and the operation principle of this device is verified through the experiments. The measurement results are analyzed by spectrum, the results show that the amplitude of main components of instantaneous torsional vibration is decreasing with the decreasing of power voltage.
2016 Vol. 37 (2): 167-170 [
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667
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171
Fault Identification of Permanent Magnet Synchronous Motor System Driving under Chaotic State
WU Zhong-qiang,WU Chang-han,JIA Wen-jing,ZHAO Li-ru
DOI: 10.3969/j.issn.1000-1158.2016.02.14
A research on fault identification of the permanent magnet synchronous motors driving under chaotic state is carried out, a fault identifier based on the wavelet support vector machine is established. After the empirical mode decomposition of the restored fault signals, serial stationary intrinsic mode functions are obtained, and their energy characteristics are used as inputs to establish a fault identifier based on the wavelet support vector machine. After training, the structure of the wavelet support vector machine and its internal parameters are fixed. The white noises usually simulate the unknown disturbances in practice. As the test inputs, the fault signals are mixed with white noises, and are identified by the fault identifier. The simulation results show that the fault identifier based on the wavelet support vector machine can identify the fault signals well, the fitting error is less than 1%.
2016 Vol. 37 (2): 171-176 [
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624
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177
Friction and Wear Testing Machine Based on ARM Microprocessor of Pneumatic Load Measurement and Control System
LIU Fu-cai,XU Wen-li,HOU Tian-tian,WANG Jia-chun
DOI: 10.3969/j.issn.1000-1158.2016.02.15
For the material surface characteristic research needs of the space operation process, a new changing load on the friction and wear tester based on the ARM microprocessor is proposed. The computer human-computer interaction interface and lower computer ARM unit is used to develop a measurement and control system of pneumatic variable load friction and wear testing machine. The loading mode using pneumatic and load forms included sine wave, square wave, sawtooth wave, triangle wave and random wave., Fuzzy-PID is used in pneumatic loading closed loop control to improve the dynamic loading performance. The influence of variable load on the tribological properties of material can be researched through measuring friction force, friction coefficient, wear, friction temperature and vibration parameters in experiment. Finally, the experiment results of A3 steel tribological properties prove that the proposed tester has stable performance and the test system is accurate and reliable.
2016 Vol. 37 (2): 177-179 [
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690
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180
End Effects Restraining of DEMD Based on Support Vector Machine and Window Function
MENG Zong,JI Yan,GU Wei-ming,WANG Na
DOI: 10.3969/j.issn.1000-1158.2016.02.16
In the process of differential-based empirical mode decomposition (DEMD), as a result of the uncertainty of the signal at both ends of the border, the end effects exist in the course of getting envelop of data, it will affect the quality of differential-based empirical mode decomposition badly, so that the decompose intrinsic mode function has no actual physical meaning. A new method for restraining the end effects of DEMD based on support vector machine (SVM) and window function is proposed, by using support vector machine for data extension on both ends of the signal, and adding a special window function after extension, and the continuation error is reduced. Simulation results and rolling bearing fault diagnosis examples show that the improved method can inhibit end effect effectively and has a higher accuracy of decomposition in rotating machinery fault diagnosis.
2016 Vol. 37 (2): 180-184 [
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674
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185
Study on Mechanical Early Weak Fault Diagnosis method Based on CEEMD and Envelope Demodulation Stochastic Resonance
WANG Dong,DING Xue-juan
DOI: 10.3969/j.issn.1000-1158.2016.02.17
Aiming at the early fault feature extraction problem of mechanical vibration signal under noise background, a novel method based on envelope demodulation stochastic resonance and CEEMD is proposed . With the method, the mechanical fault signal with noise is processed by envelope demodulation, and then through stochastic resonance system the rescaling signals are enhanced. Finally the output result is decomposed by CEEMD, obtaining the fault feature components to realize feature extraction and fault diagnosis. The rolling bearing fault diagnosis example shows that the method can not only improve the signal amplitude and reduce the false component, but also improve CEEMD algorithm precision and effectively extract fault signal submerged in noise.
2016 Vol. 37 (2): 185-190 [
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776
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191
Utility Boilers NOx Combustion Optimization Based on Relevance Vector Machine
NIU Pei-feng,MA Yun-peng,ZHANG Jing,ZHANG xin,LI Guo-qiang,CHEN Gui-lin,ZHANG Xian-chen
DOI: 10.3969/j.issn.1000-1158.2016.02.18
In order to reduce NOx emissions from utility boilers, a new machine learning method——relevance vector machine is presented. This is to build the model of a 330MW pulverized coal boiler for NOx output and twenty-six inputs such as drum first and secondary air, oxygen and so on, then gravitational search algorithm is used to optimize the parameters of the model to obtain the optimal pattern.Through comparing the outcome of particle swarm optimization‘s and genetic algorithm‘s optimizing relevance vector machine and gravitational search algorithm's optimizing support vector machine. Finally, the boiler adjustable variable input parameter is selected as the optimization variables for the target of cutting down NOx emissions to achieve the appropriate input parameters of lower NOx emissions. The result shows that gravitational search algorithm’s optimizing relevance vector machine gets better accuracy than the others, after the model of low NOx optimization, the results from the initial NOx output value of 906.65mg/m
3
becomes 550.600mg/m
3
, a decrease of approximately 38.9%, to achieve a significant reduction in NOx emissions.
2016 Vol. 37 (2): 191-196 [
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675
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197
Metrology Method of S11 Phase Based on Transmission Line Theory
ZHOU Feng,RAN Zhi-qiang,MU Dan,HU Yao-feng
DOI: 10.3969/j.issn.1000-1158.2016.02.19
S11 phase metrology methods is based on theoretical derivation of the transmission line theory. In experiment, the open kit, short kit, air lines and other standard devices are used to verify the correctness of the theory program. In the experiment, the error distribution law is also found. A mechanism model of errors is proposed, and numerical simulation verifies the rationality of the model.
2016 Vol. 37 (2): 197-199 [
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946
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200
Method of Eliminating Mode Mixing of Empirical Mode Decomposition with Intermittency Signal Based on AMD
SHI Pei-ming,SU Cui-jiao,HAN Dong-ying,LIU Shuang
DOI: 10.3969/j.issn.1000-1158.2016.02.20
Aiming at mode mixing of empirical mode decomposition (EMD) caused by the intermittency signal, a new method to eliminate mode mixing of EMD based on analytical mode decomposition, AMD, is proposed. In this method, taking advantage of instantaneous frequency characteristics of the first intrinsic mode function, IMF, the frequency components of IMF1 can be got, the bisecting frequency and the location of the intermittency signal. Then, AMD is used to extract the intermittency signal and decompose the processed signal by EMD method. Thus, the effect of the intermittency signal is eliminated. The results of simulation analysis and engineering application show that the proposed method can effectively eliminate mode mixing of EMD caused by intermittency signal.
2016 Vol. 37 (2): 200-204 [
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942
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205
An Improved Multiple Threshold Wavelet Packet De-noising Algorithm and Its Application
WANG Hong-bin,WANG Shi-hao,JI Bing-shuo,ZHANG Hang-fei,QIAO Yong-jing,Xu Jian-tao
DOI: 10.3969/j.issn.1000-1158.2016.02.21
An improved multiple threshold wavelet packet de-noising algorithm is proposed, solving the problems of eliminating the noise incompletely and removing some useful signals without distinction. It was applied to the intelligent traffic image and got rid of the image signal de-noising incompletely and wrongly. First of all, the image was preprocessed using the decomposition reconstruction's algorithm of wavelet packet, and got more edge details. Then corresponding to different frequencies, threshold was set reasonable according to the characteristics of different energy adaptively, and different threshold was used to remove noise under different frequencies. Experiments showed that the method could remove the single noise effectively while preserving the image edges and details.
2016 Vol. 37 (2): 205-208 [
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751
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209
The Absolute Measurement for 2πα and 2πβ Particle Emission Rate
LIANG Jun-cheng,LI Qi,LIU Jia-cheng,YANG Zhi-jie
DOI: 10.3969/j.issn.1000-1158.2016.02.22
Based on a large-area gas flow proportional counter, a 2π alpha and 2π beta particle emission rate measurement system is established. Performance test is executed and the results show that the plateau length of 600~800V, the optimal average plateau incline of 0.2%/100V for alpha plane sources, and the plateau length of 350~400V, the optimal average plateau incline of 0.23%/100V for beta plane sources are achieved. Uniformity for counting is measured by 239Pu alpha point source to be 0.45% in the central region of 100mm×150mm. Corrections including the background, dead time and the discrimination threshold are executed, and the absolute measurement of particle emission rate for the alpha and beta plane sources are realized. The expanded uncertainty of measurement result are better than 0.9% (k=2) for alpha sources and better than 1.1% (k=2) for beta sources. Comparisons of emission rate of 9 importing sources including 233U and 241Am etc. are executed between 2πα、2πβ primary standard equipment and new built emission rate measurement system, and the measurement results are equivalent in expanded uncertainties limits.
2016 Vol. 37 (2): 209-213 [
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696
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214
Monte Carlo Simulation and Experimental Validation of Correction Factor for Cylindrical Cavity Ionization Chamber
WU Meng-meng,LI De-hong,WANG Pei-wei
DOI: 10.3969/j.issn.1000-1158.2016.02.23
To discuss how to use nominal 10 cm3 cylindrical cavity ionization chamber to give absolute measurement to the Cs-137 air kerma. The wall correction factor kwall and the axial non-uniformity correction factor kan is determined by both the experimental method and Monte Carlo (MC) calculation. The results showed, the wall correction factor kwall determined by geometry thickness extrapolation method is less than 0.091% compared with that by the MC calculation, the axial non-uniformity correction factor kan determined by the experimental method is less than 0.63% compared with that by the MC calculation. The error between the two values is acceptable. The repeated experiment will inevitably introduce other error factors, and MC calculation method is simple and high repeatability. Eventually we selected MC calculation results for kwall, kan value.
2016 Vol. 37 (2): 214-218 [
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219
A Heart Rate Measuring System Based on the Webcam
LIU Yi,OUYANG Jian-fei
DOI: 10.3969/j.issn.1000-1158.2016.02.24
To discover a non-contact system of measuring heart rate by taking a video using a webcam, the signal containing heartbeat information is extracted from face image sequences based on photoplethysmography principle is proposed. Blood volume pulse is acquired by wavelet filtering and an improved time interval algorithm is utilized to calculate the heart rate. Experiment results indicated that when heart rate measured by the pulse oximeter is referred, the 95% confidence interval of this measurement system is [-2.2139, 2.1539], the accuracy of the system is high which meets the requirement of pharmaceuticals industry standard and it is possible to improve the accuracy by adjusting relevant parameters like light intensity, webcam's hardware configuration, etc.
2016 Vol. 37 (2): 219-224 [
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