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2013 Vol. 34, No. 2
Published: 2013-03-22
 
97 Research on Comparison Measurement of Single-crystal Silicon Sphere Density Based on  Pressure Floatation Method
LIU Zi-yong,WANG Jin-tao,XU Chang-hong, LUO Zhi-yong
DOI: 10.3969/j.issn.1000-1158.2013.02.01
To overcome the influence of liquid surface tension on the density measurement of single-crystal silicon sphere with hydrostatic method, pressure-of-flotation (PF) method and measurement system were developed to carry out the comparison measurement of single-crystal silicon sphere density. On the condition of certain temperature, the pressure of liquid was adjusted, which caused the change of liquid density, and the standard and measured single-crystal silicon spheres could be suspended in the liquid stably. By measuring liquid temperature, pressure and suspension heights, the density difference was determined. Double-level temperature control system was used to achieve stable temperature within ±0.25 mK. The liquid compress coefficient was determined by the linear equation of temperature-pressure suspension condition. It was verified by experiments that the density difference of single-crystal silicon spheres could be measured with high precision, and the standard relative uncertainty is 2×10-7.
2013 Vol. 34 (2): 97-100 [Abstract] ( 633 ) HTML (1 KB)  PDF (462 KB)  ( 606 )
101 Study of Roller Bearing Fault Diagnosis Based on the Improved Empirical Mode Decomposition
ZANG Huai-gang,LI Qing-zhi,HAN Yan-long,WANG Shi-yun
DOI: 10.3969/j.issn.1000-1158.2013.02.02
The traditional time-frequency analysis method can not effectively process non-stationary signals. The empirical mode decomposition (EMD) is very suitable for processing the non-stationary signals, but the results may appear pseudo-intrinsic mode functions (IMF) and insensitive intrinsic mode functions. For the lack of EMD, the method combined with energy threshold law and sensitive IMF select wears to identify the true IMF and sensitive IMF is proposed, then the spectrum transformation of IMF satisfying these two conditions and the diagnostic results are given. The fault information can be clearly presented on spectrogram. The improved EMD decomposition is applied to the fault diagnosis of rolling bearing to prove the feasibility and accuracy of this method.
2013 Vol. 34 (2): 101-105 [Abstract] ( 492 ) HTML (1 KB)  PDF (1291 KB)  ( 389 )
106 Compensation of Dynamic Characteristics and Evaluation of Dynamic Uncertainty for a Measurement System Modeled by a Second-order Linear Time Invariant Model
HU Hong-bo,SUN Qiao
DOI: 10.3969/j.issn.1000-1158.2013.02.03
A novel method is proposed for the design of the system compensation filter. The compensation filter is directly designed according to the frequency response data obtained by dynamic calibration, which avoiding the process of system identification. The whole process is illustrated by the realistic simulation and proved that the method can improve the dynamic characteristics effectively and reduce dynamic error. Furthermore, the uncertainty of the whole measurement process including dynamic compensation and filter process is evaluated under frame of the GUM uncertainty, and finally the output of the compensated system and its uncertainty are obtained.
2013 Vol. 34 (2): 106-110 [Abstract] ( 536 ) HTML (1 KB)  PDF (384 KB)  ( 969 )
111 The Theoretical Research and Experimental Testing on Elbow Flow Meter in High Precision
LI Shao-feng,XUE Gui-jun,MENG Xian-ju,WANG-Chi,LI Zhi
DOI: 10.3969/j.issn.1000-1158.2013.02.04
The measurement accuracy of elbow flow meter is not only related to the geometry size precision of the sensor itself in diameter, curvature radius, ratio of curvature radius and diameter, and the position of pressure tap , but also related to the condition for resting, according to the calculating N-S equations to testing elbow flow meter in theory level. Especially, the condition of the application circumstance, such as the deflection angle of installation that generated by the elbow flow and the straight section in both in front and rear sides, the consistency between diameter of straight section and the pipe diameter of itself, would influence the precision of the elbow flow meter in application as well. According to the factors motioned above, by repeatedly testing the elbow flow meter which contains straight section itself machined internally with integral NC, it could be proved that the accuracy of the elbow flow meter could reach 0.5 percent under the criteria in 2σ. Meanwhile, for the circumstance in various pipe diameters, the flow factor performed in good consistency as well.
2013 Vol. 34 (2): 111-116 [Abstract] ( 524 ) HTML (1 KB)  PDF (7411 KB)  ( 97 )
117 Study on Tobocco Critical Flow Orifice
JIANG Zhi-cai,SU Zhong-di,HAN Bin,YIN Zhao-qin,DING Xue,FANG Ting
DOI: 10.3969/j.issn.1000-1158.2013.02.05
To measure draw resistance of cigarette and pressure drop of filter better, a new perspective based on computational fluid dynamics(CFD) about critical flow orifice is studied. Three dimensional numerical simulation with the finite volume method and Realizable k-ε model has been carried out in order to get the internal flow phenomenon in critical flow orifice. Further research is conducted from the three parts: theoretical analysis, numerical simulation and experimental. Experimental data is compared with the experimental data of the volume flow rate of the critical flow orifice inlet which is measured in China Tobacco Zhejiang standardized laboratory, from the comprehensive analysis, CFO can maintain a constant volume flow rate at its front.
2013 Vol. 34 (2): 117-121 [Abstract] ( 635 ) HTML (1 KB)  PDF (1265 KB)  ( 1133 )
122 Research of Nonlinearity Error Optimization for Single Frequency Laser Interferometer
HUANG Lei,MA Hong,MA Zhong-huan,YANG Lu
DOI: 10.3969/j.issn.1000-1158.2013.02.06
To decrease the influence of  the nonlinearity error on accuracy and stability of single-frequency laser interferometer, the factors are researched. Based on the Jones matrix, the optical parameters of the system are expressed. The optimal control adjustment to improve single-frequency laser interferometer is described. Experimental results show that the ordinary adjustment is limited to improve the system accuracy. But the orthogonality of signals, interference fringe contrast and system sensitivity are improved by optimal control adjustment. The interference fringe contrast vimax,o achieve to 0.97, and the four periods of two signals turn into two periods which 1/8 wave plate is revolved.
2013 Vol. 34 (2): 122-127 [Abstract] ( 363 ) HTML (1 KB)  PDF (932 KB)  ( 492 )
128 The Blade Surface Measurement Programming and Error Processing Skill
LIN Xiao-jun,LI Yi-ming,LI Zheng-hui,GAO Chun
DOI: 10.3969/j.issn.1000-1158.2013.02.07
To investigate the measurements of aero-engine blades using coordinate measuring machine(CMM), automatic measurement programming and error processing were studied. Based on CAD model of blade, a method to extract the theoretical coordinates of the measured point was proposed, and with micro-plane theory the normal vector was also calculated in this method. ICP algorithm was used to eliminate systematic errors during data processing, and then the surface error of blade was obtained. Finally the program to calculate the coordinate and vector of measured point, as well as the program for surface matching were developed. Practical example verified the validity and reliability of the proposed method.
2013 Vol. 34 (2): 128-133 [Abstract] ( 573 ) HTML (1 KB)  PDF (932 KB)  ( 413 )
134 New Automatic Apparatus of the Melting Point of Gallium
SUN Jian-ping,CHEN Wei,QIU Ping,LIU Jian-qing,ZHANG Xin-xin
DOI: 10.3969/j.issn.1000-1158.2013.02.08
A new apparatus of the melting point of gallium is developed in National Institute of Metrology.The melting point of gallium can be realized automatically by the fixed point furnace with the three-zone freezing and heating technique.The excellent stability and uniformity of the fixed point furnace is obtained because of the precise temperature control and the reasonable design.The cell of the gallium melting point is filled with the 99.99999% purity gallium that is purified by the present technique and improved perfusion technique.The experiment results show that the plateau of the apparatus lasts more than 70 hours,and the difference of the plateau from 20% to 80% is less than 0.15 mK.The reproducibility of the apparatus is 0.07 mK,and the expanded uncertainty is 0.36  mK(k=2).
2013 Vol. 34 (2): 134-137 [Abstract] ( 442 ) HTML (1 KB)  PDF (1237 KB)  ( 668 )
138 The  Surface Temperature Measurement  of Casting Slab Based on Reflector-preceded and Multi-wavelength
LIU Jun,YANG Feng,XIE Jun,ZENG Zhen-jun,RAO Li-min
DOI: 10.3969/j.issn.1000-1158.2013.02.09
The surface temperature of casting slab is a virtual parameter in metallurgy field.So, based on reflector-preceded and multi-wavelength,a method to dealing with the difficulty in surface temperature measurement of casting slab is put forward.On the premise of reflector-preceded and non reflector-receded, the method establishes the radiation energy equations, works out the emissivity and temperature in the equations.As well,the multilayer modeling of casting billet surface and multiple reflection-absorption process modeling by Monte-Carlo method are built.Finally, the ansysis result of the models shows that the method can measure the casting billet surface temperature accurately.
2013 Vol. 34 (2): 138-142 [Abstract] ( 487 ) HTML (1 KB)  PDF (1380 KB)  ( 493 )
143 Research and Application on Energy Model and Energy Measurement Technology
ZHAO Xiao-dong
DOI: 10.3969/j.issn.1000-1158.2013.02.10
The Dynamic multi-parameter online energy measurement technology is studied, and applied to establish a huge energy database after acquiring and storing the real-time enterprise energy consumption data of the energy sector, accurately and stably in working conditions. On the basis of the material balance and energy conservation principle, the mathematical model of the conversion process between production and energy and the model of the unit comprehensive energy consumption are established by the method of the energy consumption benchmark factor method and the e-p analysis. And production process and equipment energy consumption, unit energy consumption and product energy are evaluated and calculated as well. The models are used to the energy measurement and systems of a major brewery in Beijing successfully. Through the analysis and comparison of equipment and production process energy consumption, the system has directed production process optimization and energy-saving space assessment, and reasonably predicts the production process and equipment energy consumption.
2013 Vol. 34 (2): 143-148 [Abstract] ( 452 ) HTML (1 KB)  PDF (4623 KB)  ( 598 )
149 Error Analysis of the Face to Face Sound Intensity Probe under a Standing Wave Field
CHEN Pin,LU Yi-min,BI Chuan-xing,CHEN Xin-zhao
DOI: 10.3969/j.issn.1000-1158.2013.02.11
According to the structural characteristics of the face-to-face configuration,based on the microphone equivalent acoustic models,the phase mismatching characteristic of sound intensity probe is analyzed.Then the causes of error and the distribution curves of the face to face sound intensity probe under a standing wave field are discussed in detail.Tiny standing wave field caused by support brackets will affect the accuracy of phase calibration.An improved method is proposed.Finally,the analysis models and conclusions are verified by experimental results.
2013 Vol. 34 (2): 149-154 [Abstract] ( 520 ) HTML (1 KB)  PDF (4137 KB)  ( 494 )
155 Fast Calculation of Transient Eddy Current Field in Cylindrical Conductor Excited by Pulsed Magnetic Field
XIN Wei
DOI: 10.3969/j.issn.1000-1158.2013.02.12
The theoretical model of transient eddy current field is built in cylindrical conductor excited by pulsed magnetic field.Theoretical calculation and experimental measurement of cylindrical conductor in pulsed magnetic field are carried out.The theoretical results are compared with the experimental results in a good agreement,indicate that the fast calculation method of transient eddy current field in cylindrical conductor is effective.
2013 Vol. 34 (2): 155-160 [Abstract] ( 515 ) HTML (1 KB)  PDF (1339 KB)  ( 706 )
161 A Monolithic Scheme Based Femtosecond Optical Frequency Comb  Covering 633nm Wavelength
LIANG Zhi-guo,WEI Zhi-yi,HAN Hai-nian,ZHANG Da-peng,YE Peng,WU Teng-fei
DOI: 10.3969/j.issn.1000-1158.2013.02.13
Femtosecond optical frequency comb is considered as a precise gear between the optical frequency and radio frequency. Both self reference phase lock optical frequency combs and monolithic scheme laser combs are compared, the former has wider spectrum and uglier stability, but the other has better stability and thinner  spectrum. Based on the monolithic scheme laser comb, through compressing laser pulse width outside the cavity, then by using photonic crystal fiber widen spectrum, obtain wider spectrum, and the 633nm wavelength is covered, it can be applied to measure the optical frequency including 633nm wavelength.
2013 Vol. 34 (2): 161-167 [Abstract] ( 543 ) HTML (1 KB)  PDF (1824 KB)  ( 564 )
168 Removing Power Frequency Noise in sEMG with Matched Filtering and ICA
ZHANG Qi-zhong,XI Xu-gang,GAO Fa-rong
DOI: 10.3969/j.issn.1000-1158.2013.02.14
A new method of removing power frequency noise in surface electromyography(sEMG) is designed with matched filtering and independent component analysis. It can be judged effectively whether surface electromyography includes the power frequency noise with matched filtering. It can be avoided that the power frequency noise filter is abused. Under this premise that surface electromyography includes the power frequency noise, the power frequency noise can be removed effectively and the other frequency components is not affected significantly by using independent component analysis. The experiment proved that this method is effective.
2013 Vol. 34 (2): 168-172 [Abstract] ( 551 ) HTML (1 KB)  PDF (1944 KB)  ( 941 )
173 A Signals Feature Extraction Method Based on the EEMD and Chaotic and  Its Application
ZHANG Shu-qing,DONG Xuan,ZHAI Xin-pei,GONG Zheng
DOI: 10.3969/j.issn.1000-1158.2013.02.15
A method of feature extraction combining ensemble empirical mode decomposition (EEMD) with chaotic, and  its application  to the asthma detection in infants breathing signal are described. The partial infant breathing signal was decomposed by EEMD into a series of frequency mode components, which spread from high frequency components to low ones. The correlation between each component and partial signals was analyzed and the Hilbert spectral for major components was listed. From the partial signal, it may be generally determined whether the child suffered asthma. Then, the frequency calculated by EEMD from partial signals was chosen as the chaotic oscillator frequency to detect and analyse global breathing signals. It could express the original breathing signal frequency from the intermittent cycle of chaotic time-domain waveform, and confirm the result for infant asthma detection eventually. The EEMD and chaos algorithms were improved in order to succeed in their application. The method was put into the real data analysis and its efficiency was verified. It reflects the signals information correctly and has a high accuracy.
2013 Vol. 34 (2): 173-179 [Abstract] ( 479 ) HTML (1 KB)  PDF (4051 KB)  ( 666 )
180 Establishment and Performance Testing of Measurement System for 4πγ Ionization Chamber Radioactivity Standard
LIU Jia-cheng,WU Yong-le,LIANG Jun-cheng,YUAN Zhi-lun,CHEN Jing,YANG Yuan-di
DOI: 10.3969/j.issn.1000-1158.2013.02.16
A measuring system based on Townsend induction balance method for 4πγ ionization chamber radioactivity standard is developed. The measuring system consists of high voltage source, voltage measurement, compensation circuit and control software. During Townsend balance process, the leakage currents and offset current are small in comparison with the current to be measured. The leakage and background current obtained with the measuring system is less than 3×10-14A. Measurements are performed to check the repeatability, stability, linearity and angle response of the system. The testing result shows that the measuring system meets the requirement of 4πγ ionization chamber radioactivity standard.
2013 Vol. 34 (2): 180-183 [Abstract] ( 458 ) HTML (1 KB)  PDF (970 KB)  ( 504 )
184 The Wavelet Projection Pursuit Regression Method of Near-infrared Spectroscopy Calibration
ZHOU Yang,DAI Shu-guang,LV Jin,LIU Tie-bing,SHI Yang,CHEN Cai,LI Bo-bin
DOI: 10.3969/j.issn.1000-1158.2013.02.17
To improve the fitting degree between structural characteristics of near-infrared spectroscopy and non-linear quantitative regression model, a quantitative calibration method by the wavelet projection pursuit  is proposed. The method reduces the noise of NIR wavelet coefficients by gaussian mixture model noise estimation method. After finding optimal low-dimensional projection of the spectrum wavelet coefficients,  the calibration model was fitted by the polynomial ridge regression. The experiment sets up wine alcohol prediction model of near infrared spectroscopy by wavelet projection pursuit regression method, the R2 and RMSECV are 0.957 and 0.37838, comparing with quantitative effect of multiple linear regression and partial least squares regression, spectral wavelet projection pursuit method has better prediction performance that can be more effectively applied quantitative analysis of near infrared spectroscopy.
2013 Vol. 34 (2): 184-186 [Abstract] ( 500 ) HTML (1 KB)  PDF (328 KB)  ( 547 )
187 Development of a New Certified Reference Material of Ginsenoside Rg1, Re and Rb1 in Panax Quinquefolium
REN Zhong-nan,LIU Jun,HUANG Ting,YANG Yi
DOI: 10.3969/j.issn.1000-1158.2013.02.18
A new certified reference material (CRM) of ginsenoside Rg1, Re, and Rb1 in Panax quinquefolium is developed and measured by two different methods, high performance liquid chromatography method and high performance capillary electrophoresis method.Simultaneously, the homogeneity and the stability are studied, and the evaluation of uncertainty is calculated.  The mass fractions of ginsenoside Rg1, Re, and Rb1 are (1.72±0.14)mg/g, (15.3±1.5)mg/g, (25.8±2.8)mg/g, with the expanded uncertainty of 8.3％, 10％, 11％.The new certified reference material of ginsenoside Rg1, Re, and Rb1  in Panax quinquefolium is capable to validate analytical measurements  in laboratories.
2013 Vol. 34 (2): 187-191 [Abstract] ( 345 ) HTML (1 KB)  PDF (601 KB)  ( 620 )
192 The Design and Data Evaluation for Chemical Quantities forSmall Scale Inter-laboratory Measurement Comparison
LU Xiao-hua,JI Jie,MENG Fan-min,KAN Ying,ZHANG Qing-he,WANG Wei-hua
DOI: 10.3969/j.issn.1000-1158.2013.02.19
To ensure the reliable assessment of laboratory measurement capability,a small scale inter-laboratory comparison was organized. In this comparison the design of scheme arrangement and samples, the distribution testing of data received, the determination of reference values, the performance judgment and analysis of laboratory results were considered. It was also studied on how to reduce the influence of collusion and enhance the scientific rigorousness of inter-laboratory comparison for chemical measurements.
2013 Vol. 34 (2): 192-195 [Abstract] ( 481 ) HTML (1 KB)  PDF (743 KB)  ( 578 )
196 Uncertainty Evaluation for the Determination of Mo in Geological Samples by Spectrophotometr
ZHANG Ji-guang
DOI: 10.3969/j.issn.1000-1158.2013.02.20
The sources of measurement uncertainty for the analytical results of Mo content in geological samples by spectrophotometry is determined and sub-uncertainties of the analytical results are evaluated through studying the whole process of the analytical results. With the least square method,the calibration curve is fitted. Through the evaluation of the analytical results of various contents of two samples, the sub-uncertainties from the sample repeated measures and the fitting of the calibration curve are the major contributor to the expanded uncertainty. And it shows that the lower the concentrations of Mo, the greater the relative standard uncertainty of analytical results.
2013 Vol. 34 (2): 196-200 [Abstract] ( 526 ) HTML (1 KB)  PDF (953 KB)  ( 501 )
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