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2013 Vol. 34, No. 4
Published: 2013-07-22
 
305 Blind Source Separation of Underdetermined Signals Based on Extremum Field Mean Mode Decomposition
MENG Zong, LIANG Zhi, ZONG Zhen-wei, HUI Shao-nan
DOI: 10.3969/j.issn.1000-1158.2013.04.01
The ordinary blind source separation (BSS) methods is based on the assumption, which the number of observation signals is no less than that of the source signals.  The result of BSS will be relatively poor when the number of observation signals less than source signals. However, the problem of underdetermined BSS, even single observation channel BSS, is common in vibration signals of rotating machinery.To solve the single observation channel problem, a new BSS method based on extremum field mean mode decomposition (EMMD) is proposed.Firstly, by EMMD, the underdetermined observation signal is decomposed to a series of intrinsic mode function (IMF), then the underdetermined observation signal and IMFs compose multi-dimensional signal, to increase the dimensions of observation signals.Secondly,  the number of source signals is estimated with singular value decomposition and Bayesian information criterion.〖JP2〗Finally, the characteristic matrix joint diagonalization method based on fourth-order cumulant is used to achieve BSS.The simulation study on rotating machinery fault signal indicates that it can well solve the problem of BSS with underdetermined observation signal.
2013 Vol. 34 (4): 305-310 [Abstract] ( 450 ) HTML (1 KB)  PDF (1531 KB)  ( 637 )
311 30kN·m Multifunction Torque Standard Machine
MENG Feng, ZHANG Zhi-min, ZHANG Yue, LI Tao, JI Hong-lei
DOI: 10.3969/j.issn.1000-1158.2013.04.02
A set of 30kN·m multifunction torque standard machine is developed at National Institute of Metrology （NIM）. The hydraulic torque wrench, torque multiply and torque transducer may be calibrated by this machine. The machine mainly consists of standard torque transducer, operating platform, lifting platform, driving system and lifting system. It has high accuracy and multi-function characteristics.
2013 Vol. 34 (4): 311-314 [Abstract] ( 596 ) HTML (1 KB)  PDF (337 KB)  ( 639 )
315 Study  on  Wave  Buoy  Data  Processing  Algorithm
TANG Chang, WANG Nan- nan, HE Gai- yun, SONG Zhan- jie
DOI: 10.3969/j.issn.1000- 1158.2013.04.03
In order to improve accuracy of wave parameters, polynomial fitting algorithm is applied to eliminate indirect errors produced by the trend errors during the integrating process. Simulation experiment and real data test show good results of this approach, it can get more accurate wave height, period and other parameters.
2013 Vol. 34 (4): 315-319 [Abstract] ( 589 ) HTML (1 KB)  PDF (1539 KB)  ( 1136 )
320 Water Colority Determination Based on Color Difference
SHEN Wei-min,YU Pan,HUANG Jie,XU Ben,ZHAO Xiao-wei,YU Qing
DOI: 10.3969/j.issn.1000-1158.2013.04.04
For overcoming the limitation of the present water colority measurement method and meeting the requirement of measuring the water colority automatically, a  measuring method of the water colority by color difference value is proposed. The relationship between color difference value and water colority value has been established by experiments, and the water colority value can be obtained based on the color difference value which calculated by measuring the spectral transmittance of water sample. Based on the proposed method, the calibrated system no longer needed the standard solutions during measurement and can be applied to measure any color of water sample. The measurements of natural water show that the measuring results are not only conforming to the measuring results by national standard method, but also higher sensitivity and better repetitiveness.
2013 Vol. 34 (4): 320-324 [Abstract] ( 438 ) HTML (1 KB)  PDF (1446 KB)  ( 1126 )
325 Development  of the Multi-functional Portable Color Temperature Meters
HUANG Yan, ZHANG Han
DOI: 10.3969/j.issn.1000-1158.2013.04.05
A new scheme for the portable color temperature meter is proposed, which is based on the color temperature experience formula, using the selenium color sensors based on light-frequency conversion, the singlechip, digital circuit and software correction to control the system and calculate the color temperature. According to JJG212—2003, tests are performed. The results show that the technique specifications of the color temperature meter all meet or excel the requirements of JJG212—2003.
2013 Vol. 34 (4): 325-329 [Abstract] ( 483 ) HTML (1 KB)  PDF (356 KB)  ( 605 )
330 Uncertainty Analysis for Spectral Radiant Intensity Measurements of LEDs
YIN De-jin, LIU Wei, LAI Lei, HUANG Bi-yong, LI Tie-cheng
DOI: 10.3969/j.issn.1000-1158.2013.04.06
Uncertainties associated with measurements of LEDs are extremely important.By choosing specific quantities,devices under test and equipments,  the process of uncertainty budgets by example can be analyzed.Spectroradiometer measurements are traceable to NIM spectral irradiance scale.The particular LED was chosen because it also has an independent NIM traceable calibration via another path and can provide verification of measurements.The uncertainty of spectral radiant intensity measurements of LEDs is analyzed through experiment and calculation.
2013 Vol. 34 (4): 330-333 [Abstract] ( 501 ) HTML (1 KB)  PDF (430 KB)  ( 991 )
334 The Impact of Expansibility Factor of V Cone Flowmeters on Aerometry
LIU Xing-xun, ZHANG Tao, BAI Long
DOI: 10.3969/j.issn.1000-1158.2013.04.07
The experiments about V cone flowmeter both in the water flux standard instrument using weighing method and the gas flow calibration system based on the critical flow nozzles and positive pressure method were carried out. Based on the experiment value and the uncertainty mathematical model of fitting coefficient on the least squares method, uncertainty has been evaluated and compared between the expansibility factor calculation formulas proposed by NEL and Xu Ying respectively. The result can be concluded that the uncertainty about formulas mainly come from the error of fitting coefficient. After analysis of the prediction of expansibility factor respectively by traditional V cone formula and wafer V cone formula, the optimal structure of v cone is very important for the standard V cone flowmeter.
2013 Vol. 34 (4): 334-338 [Abstract] ( 484 ) HTML (1 KB)  PDF (324 KB)  ( 611 )
339 Study on Electromagnetic Flowmeter Sensor Signals Based on Two-phase Flow
KONG Ling-fu, WANG Yue-ming, LI Ying-wei, LIU Xing-bin, ZHANG Yu-hui
DOI: 10.3969/j.issn.1000-1158.2013.04.08
The electromagnetic flow meter is widely used in the two-phase flow measurements of oil and water in recent years.  Since the non-conductive material exists in the two-phase flow of oil-water, the non-conductive material has some impacts on measurement of the flow meter. The simulation model of magnetic field distribution is built by the finite element software ANSYS, and the non-conductive material on the weighting function effect of the electromagnetic flow meter is discussed. The simulation model of the fluid is established by FLUENT. Furthermore, the relationship between different flow rates and water contents with response characteristics of electromagnetic flowmeter is analyzed.  The simulation result is verified by experiments in the Simulation Wells.
2013 Vol. 34 (4): 339-344 [Abstract] ( 577 ) HTML (1 KB)  PDF (1812 KB)  ( 745 )
345 Study of No-liquid Calibration Technique for the Medium-and-large Diameter Electromagnetic Flowmeter
TANG Si-meng, HU Liang, MA Jun
DOI: 10.3969/j.issn.1000-1158.2013.04.09
A no-liquid calibration technique for electromagnetic flowmeter (EMF) is presented. The proposed method utilizes the electromagnetic measuring principle. Several differential equations for the relevant physical quantities and corresponding boundary conditions are established. A set of no-liquid calibration equipment is designed and implemented. By measuring the point-by-point magnetic induction on the boundary surface as well as the structure dimensions of EMF, the sensitivity of EMF are acquired via the numerical solution of the differential equations with measured boundary conditions. The comparison of the no-liquid and practical-flow calibration methods is carried out on two EMFs with diameter of 200mm. The relative error of the sensitivity data determined by the two methods is less than 0.5%.
2013 Vol. 34 (4): 345-349 [Abstract] ( 510 ) HTML (1 KB)  PDF (1236 KB)  ( 776 )
350 Development of Reservoirs Flow Rate Online Monitoring Device in Production Wells
LI Li-pin, DANG Rui-rong, SUN Liang-liang, YIN Guang, ZHAO Dong-sheng
DOI: 10.3969/j.issn.1000-1158.2013.04.10
A set of reservoirs flow rate online monitoring device is developed and it is used in production wells,including a static mixer,flow measurement and phase fraction measurement.Doppler frequency difference is applied to measure total flowrate and two-energy level X ray with no environmental security risks is adopted to measure phase fractions in oil,gas, water three-phase fow and conductance sensors is used to test water fraction quickly in high water fraction three-phase flow. A series of experiments were carried out on the indoor three-phase flow experimental system.Experimental results show that measurement error of water and oil is less than ±7% and gas is less than ±14%.
2013 Vol. 34 (4): 350-355 [Abstract] ( 500 ) HTML (1 KB)  PDF (1085 KB)  ( 493 )
356 Study of Inhomogeneity Test on Thermocouple in Liquid Bath
ZHENG Wei, YANG Zhen-hua, XIANG Ming-dong
DOI: 10.3969/j.issn.1000-1158.2013.04.11
The method of measuring the immersion characteristic in a liquid bath at 250 ℃ to estimate the inhomogeniety of thermocouple is introduced.Experimental apparatus can produce a large temperature gradient field in a small gap above the bath,when the electric pole of the thermocouple scan the field,the thermoelectrics at different locations are recorded.A group of fresh Pt10Rh-Pt thermocouples and an used one are tested.The repeatability of datum is satisfied,and the homogeneity of fresh thermocouples is better than the used one,which is concorded to logical presumption.
2013 Vol. 34 (4): 356-359 [Abstract] ( 487 ) HTML (1 KB)  PDF (2028 KB)  ( 634 )
360 The Application of Modified Shuttled Frog Leaping Algorithm in the Positioning of Wireless Sensor Network
FENG Chen, ZHANG Ling-hua
DOI: 10.3969/j.issn.1000-1158.2013.04.12
To improve the node positioning accuracy of the DV-Hop (Distance Vector Hop) algorithm in wireless sensor network, a method with the modified shuttled frog leaping algorithm is proposed. At first,  the unknown nodes are located by DV-Hop algorithm, then  the source of error and transform localization mechanism into solving a total nonlinear least squares model is analyzed. Afterwards, the reasonable weighting factor and fitness function are choosed. Meanwhile, the modified shuttled frog leaping algorithm with chaos mapping and Cauchy mutation is used to optimize the location of the unknown nodes. In the experiment, least square method, particle swarm optimization and modified shuttled frog leaping algorithm are compared. The results show that the intelligent algorithm is not only easy and reliable, but also the precision of the node positioning efficiently is improved.
2013 Vol. 34 (4): 360-365 [Abstract] ( 439 ) HTML (1 KB)  PDF (1199 KB)  ( 773 )
366 Research on the Digital Waveform Intensity Adjustment and Correction Technology of Data Acquisition System
ZHANG Qin-chuan, WANG Hou-jun
DOI: 10.3969/j.issn.1000-1158.2013.04.13
In the data acquisition system, parallel technology is used frequently to improve the waveform capture rate,and makes use of the three dimensions of signal: amplitude,time and the amplitude distribution in time and the waveforms acquired in short time will be mapped into a picture with wave intensity or color grade.In this process, the waveform intensity adjustment and correction technology ensures that waveform display intensity hardly changes with the number of waveforms captured,and shows as much as possible the details of the waveform captured.The waveform intensity mapping process is analyzed,on this basis,the mathematical model of the waveform intensity adjustment and correction technology is described.With engineering applications, its function is designed in the digital three-dimensional oscilloscope,the waveform intensity is not changed basically and the more details of the waveform  is showed.
2013 Vol. 34 (4): 366-371 [Abstract] ( 489 ) HTML (1 KB)  PDF (2882 KB)  ( 706 )
372 Analysis on a New Free-space Technology for the Measurement of Complex Permittivity
FANG Wei-Hai, NIAN Feng, CHEN Yun-Mei
DOI: 10.3969/j.issn.1000-1158.2013.04.14
A new free-space measurement for the complex permittivity is proposed.In this method,dielectric periodic structure (DPS) is introduced to the measurement of complex permittivity for the first time.The scattering characteristics of DPS added lossy sample layer are systemically analyzed by a method which combines the multimode network theory with the rigorous mode matching method.The effects of sample complex permittivity on the amplitudes and center frequencies of the maximum reflections are analyzed in details.The method not only overcomes the instability problem and phase-shift ambiguity which exist in the traditional free-space measurement,but also possesses the merit of cavity measurement technique which can accurately determine the complex permittivity of low lossy materials with simple measurement process.The research provides a new method and important theoretical guidelines for the accurate measurement of complex permittivity.
2013 Vol. 34 (4): 372-377 [Abstract] ( 565 ) HTML (1 KB)  PDF (1639 KB)  ( 449 )
378 The Research Progress of the Josephson Array Device
GUO Xiao-wei, CHI Zong-Tao, CAO Wen-hui, Zhong Qing, HE Qing, LI Jin-jin
DOI: 10.3969/j.issn.1000-1158.2013.04.15
The application of the Josephson effect used for voltage standards is introduced. The development of the Josephson array in the field of voltage standard and the current research status of the Josephson array at home and abroad are summarized. Furthermore, the research progress of the Nb/NbxSi1-x/Nb junction used for voltage standard in domestic is introduced with emphasis.
2013 Vol. 34 (4): 378-382 [Abstract] ( 710 ) HTML (1 KB)  PDF (1294 KB)  ( 2222 )
383 Low Frequency Microphone Calibration Based on the Related Microphones Method
CHEN Hong-jiang, HE Long-biao
DOI: 10.3969/j.issn.1000-1158.2013.04.16
A new method  for frequency response calibration of measured microphones over the range of 0.1 to 250 Hz is described.If required,these frequency response calibrations can be combined with absolute sensitivity calibrations at 251.2 Hz.They might either be performed by comparison with another microphone or by using a calibrated sound source.The effectiveness and practicality of the method are verified by the measurement experiments and datum analysis.
2013 Vol. 34 (4): 383-386 [Abstract] ( 683 ) HTML (1 KB)  PDF (1116 KB)  ( 459 )
387 A Trace-gas Concentration System Based on Photoacoustic Spectroscopy with Erbium Doped Fiber Laser and A T-type Length-regulated Photoacoustic Cell
ZHENG De-zhong, ZHAO Nan
DOI: 10.3969/j.issn.1000-1158.2013.04.17
A trace-gas concentration system is designed based on photoacoustic spectroscopy. Erbium-doped fiber laser is used as a light source for acetylene detection. A T-type length-regulated photoacoustic cell is designed as first longitudinal single reflection resonance mode. The modulation frequency is 1099 Hz.Second-harmonic detection technology is used as the basic principle of the signal processing.Triangular wave is used to modulate the light source signal.The ratio between the second harmonic coefficients and the first harmonic coefficients as the system output, and the relationship curve about impact factors has been drawn. Experimental results with different concentrations of acetylene gas show that, the detection sensitivity of the system is 9.634×10－6,and signal-to-noise ratio is 41.52 dB.
2013 Vol. 34 (4): 387-392 [Abstract] ( 473 ) HTML (1 KB)  PDF (1638 KB)  ( 547 )
393 The International Comparison on Activity Measurements  of Medical Radionuclide 99Tcm with a 4πγ Well-type NaI Crystal Transfer Instrument
ZHANG Ming, LIANG Jun-cheng, LIU Hao-ran,YANG Yuan-di, CHEN Jing
DOI: 10.3969/j.issn.1000-1158.2013.04.18
99Tcm is a short-lived radionuclide and has been widely used in most nuclear medicine.The accuracy of its activity value is very important for applications.Therefore,BIPM organized the international key comparison on the activity of 99Tcm.In March of 2012,the activity measurement of 99Tcm was carried out at the National Institute of Metrology (NIM) in China,with a well-type NaI crystal transfer instrument of the International Reference System (SIRTI) which was set up by BIPM.The stability and reproducibility results show that the status of SIRTI met the requirements of comparison,and the measured equivalent activity of 99Tcm is about 12.580 kBq.
2013 Vol. 34 (4): 393-396 [Abstract] ( 496 ) HTML (1 KB)  PDF (1677 KB)  ( 811 )
397 Application of Data Visualization and Numerical Analysis to Uncertainty Evaluation
ZHOU Xin, FANG Hong, HOU Li-xin, LIU Ke, ZHAO Hai-ning, AN Ying, BIAN Xin
DOI: 10.3969/j.issn.1000-1158.2013.04.19
Propagation is a key factor in uncertainty evaluation.A new method with data visualization and numerical analysis for evaluating the uncertainty propagation is proposed.The main procedure is described followed by details in several linear and nonlinear model examples.The results show that data visualization and numerical analysis can be helpful to provide a concise qualitative overview and an accurate quantitative analysis for uncertainty evaluation.
2013 Vol. 34 (4): 397-401 [Abstract] ( 428 ) HTML (1 KB)  PDF (849 KB)  ( 905 )
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