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2014 Vol. 35, No. 6 Published: 2014-11-22

	521	Research for Reproducing SI Unit of Capacitance by the Calculable Capacitor with a Movable Guard Rod
		LU Zu-liang,HUANG Lu,YANG Yan,ZHAO Jian-ting,QIAN Jin,LU Wen-jun,LIU Zhong-you,ZHANG Zhong-hua,LIU Xiu-ying,WANG Jian-bo,WANG Wei,HE Xiao-bing
		DOI: 10.3969/j.issn.1000-1158.2014.06.01
		A new type calculable capacitor with a movable guard rod has been built in National Institute of Metrology of China at the standard uncertainty of 2×10^-8. The SI unit of capacitance reproduced by the calculable capacitor depends on the axial length which is measured by a laser interferometer. However the huge integral number of the fringe is in general not given by the laser interferometer. In a classical approach the substitution measurements were adopted to extend the integral number from a known smaller value to the bigger one. It needs some additive devices and complex operations. A novel approach is proposed. The required integral number is determined by the other capacitance standard with a lower accuracy, and the decimal number is determined by the capacitance bridge with a transfer capacitor. The details of this approach and its advantages are presented. An experiment to check the linear is reported.
		2014 Vol. 35 (6): 521-527 [Abstract] ( 670 ) HTML (1 KB) PDF (4851 KB) ( 809 )

	528	Research on the National Voltage Standard for 30 kHz~30 MHz
		HE Zhao,HUANG Jian-ming,TIAN Wei
		DOI: 10.3969/j.issn.1000-1158.2014.06.02
		Based on coaxial thermal voltage converters, the national voltage standard for 30 kHz~30 MHz has been established by National Institute of Metrology (NIM). The results of theoretical analysis and experiments indicate that in the frequency band of 30 kHz to 30 MHz and voltage range 0.1 V to 100 V, the uncertainty is 0.01% to 0.1% (k=2). This accomplishment has filled the gap of the national voltage standard in 1~30 MHz.
		2014 Vol. 35 (6): 528-533 [Abstract] ( 518 ) HTML (1 KB) PDF (899 KB) ( 499 )

	534	EMG Signal Recognition Based on EMD Sample Entropy
		XI Xu-gang,ZHU Hai-gang,LUO Zhi-zeng,ZHANG Qi-zhong
		DOI: 10.3969/j.issn.1000-1158.2014.06.03
		According to the chaotic and nonlinear characteristics of surface electromyography(sEMG), a fast and efficient hands movement sEMG pattern recognition method for real-time control of myoelectric prosthetic hand is designed. A multi-modeling pattern recognition method of sEMG features based on the empirical mode decomposition(EMD) sample entropy and clustering analysis is proposed. First, it decomposes the sEMG signal into a set of intrinsic mode functions (IMF), then combines some of the IMF which contains the useful information according to frequency effectiveness, and calculates the sample entropy of the combination.The sample entropy of two sEMG of the extensor carpi ulnaris and flexor carpi ulnaris constitute the feature vector, the clustering classifier which based on principal axis clustering arithmetic is applied to classify the four hand movements. The result shows that four movements (hand extension, hand grasps,wrist spreads and wrist bends) are successfully identified.The average recognition rate is 93%.The method achieved high recognition rate, anti-interference ability and less computation, that is suitable for the control of the myoelectric prosthetic hand.
		2014 Vol. 35 (6): 534-539 [Abstract] ( 649 ) HTML (1 KB) PDF (863 KB) ( 862 )

	540	Uncertainty Estimation for the Measurement Results of Impedance Stabilization Network
		LIU Xiao, XIE Ming,LI Bo
		DOI: 10.3969/j.issn.1000-1158.2014.06.04
		According to standard GB9254—2008,impedance stabilization networks (ISNs) are used when performing the common mode disturbance measurements at the telecommunication ports. ISN has four key parameters which are common mode impedance, voltage division factor, longitudinal conversion loss and decoupling attenuation. However the uncertainty estimation for ISN measurement results is not given in current standards. Therefore based on the measurement procedures, the uncertainty budget and results are given for the measurement results of the four parameters. The uncertainty can be directly used in the uncertainty estimation for common mode disturbance measurements at the telecommunication ports.
		2014 Vol. 35 (6): 540-544 [Abstract] ( 515 ) HTML (1 KB) PDF (413 KB) ( 678 )

	545	Experiment and Analysis of the Measuring Current Transformer with DC Bias and Remnant Flux
		SHENLu,ZHAOShu-tao,ZHANGPei,TIANXiao-qian
		DOI: 10.3969/j.issn.1000-1158.2014.06.05
		DC bias and remnant flux will change the measuring current transformer working point in the core magnetization curve and have a direct impact on the accuracy of electric energy measurement.An error measurement method based on the algorithm for three-parameter least squares fit to sine wave is put forward and the influence of DC bias and remnant flux on error characteristics of current transformer is also investigated through experiments.The experimental data shows that DC bias and remnant flux will increase the ratio error and phase displacement in opposite directions and the ratio and phase displacement will be far more than the limit value when they are exist in same direction at the same time .This will seriously affect the transmission accuracy of current transformer.
		2014 Vol. 35 (6): 545-549 [Abstract] ( 541 ) HTML (1 KB) PDF (1314 KB) ( 587 )

	550	Projection Method Measurement on Non-rigidity Gear Pitch Cumulative Errors
		XU Yao-dong,ZHENG Wei
		DOI: 10.3969/j.issn.1000-1158.2014.06.06
		To resolve the problem of micro gear or non-rigidity gear position alteration errors, a non-contact projection measurement method is adopted. Appling projection measurement appliance and rotary table by single pitch method and span pitch add-on spot method, through compensation of division errors of rotary table, gear pitch cumulative errors measurement is finished which is proved reasonable by absolute method measurement. Through analysis of the install gear eccentric errors, instrument measuring errors and aiming alignment errors, the gear pitch cumulative errors uncertainty is got about ±65μm by single pitch method and ±64μm by span pitch add-on spot method which all meet the demand of measurement precision. Finally, a conclusion is made that the tested non-rigidity plastic gear precision level is confirmed as 10 level by both measuring methods. By comparison, span pitch add-on spot method has more advantage in less measuring times and easy control in gear pitch cumulative errors measurement.
		2014 Vol. 35 (6): 550-554 [Abstract] ( 652 ) HTML (1 KB) PDF (487 KB) ( 725 )

	555	The Location Error Compensate of Aspheric CNC by Tangent Method
		YU Bo, YU Zheng-lin,GU Li-dong,ZHOU Jia-he,QU Chao-ping
		DOI: 10.3969/j.issn.1000-1158.2014.06.07
		Based on feed-forward PID algorithm and UMAC software, a compensate location error methed is proposed for the aspheric CNC by tangent method which was developed by ourselves, and specific steps to implement this method is given. The experimental results of location error compensation showed this method can improve the location accuracy of CNC effectively by the established feed-forward PID model and an UMAC error correct table.
		2014 Vol. 35 (6): 555-558 [Abstract] ( 487 ) HTML (1 KB) PDF (1057 KB) ( 494 )

	559	Analysis of Error Factor Impacting on the Performance of Laser-driver Injection Compound Lens
		BAI Zhan-wei,XIE Zhi-jiang,YUAN Xiao-dong
		DOI: 10.3969/j.issn.1000-1158.2014.06.08
		During the study of all kinds of tolerance influencing factors on the performance of injection compound lens made of high power laser inertial confinement fusion drive,analysis shows that geometry dimension tolerance of the lens,lens assembly tolerance and compound lens have a significant effect on the perfomance of compound lens focal length tolerance,focal spot position and wave aberration.According to the main influencing factors,related performance mathematical models are set up.The models are simulated and the results of simulation are analyzed based on the software platform of Matlab and Zemax. The manufacturing and installation tolerance ensuring the performance are also determined based on the simulation results and tolerance of compound lens.
		2014 Vol. 35 (6): 559-564 [Abstract] ( 447 ) HTML (1 KB) PDF (764 KB) ( 421 )

	565	The Development and Traceability Method of a Special Designed Multiport UV Solar Simulator for Calibration
		DAI Cai-hong, WU Zhi-feng, WANG Yan-fei, CHEN Bin-hua, QI Xiao-jin, YE Jing
		DOI: 10.3969/j.issn.1000-1158.2014.06.09
		A multi-channel ultraviolet sunlight simulator and traceability system studied and established. The solar simulators output spectral distribution can satisfy the European cosmetics toiletries and perfumery association and Japan cosmetic industry association technical index requirements. The optical radiation calibration and measurement is developed, effectively solve the analog meter output intensity is small, uneven distribution of irradiation, optical measurement problem such as bending is easy to change the spectral distribution. The simulation instrument spectral radiant intensity of illumination and spectral matching the high accuracy of measurement, and UVA radiation intensity of illumination and UVA+B integral accurate traceability of the value are realized. And SPF ultraviolet radiation intensity of illumination measuring instrument is developed, this can be used for UVA radiation intensity of illumination and UVA+B integral value measurement, preservation and delivery of the national reference unit quantity traceability to the spectral radiant intensity of illumination.
		2014 Vol. 35 (6): 565-568 [Abstract] ( 494 ) HTML (1 KB) PDF (316 KB) ( 451 )

	569	Occlusion Boundary Detection Method for Depth Image Based on Ensemble Learning
		ZHANG Shi-hui,PANG Yun-chong
		DOI: 10.3969/j.issn.1000-1158.2014.06.10
		The existing occlusion detection method for depth image can not effectively detect the occlusion boundary point with less obvious depth change, this status should be changed. The eight neighborhood total depth difference feature and maximal area feature are proposed firstly, and then the calculation methods for these two new features are defined. On this basis, a new occlusion detection approach based on ensemble learning is proposed, which combines the proposed features and existing occlusion related features to train the decision tree-based AdaBoost classifier to classify the pixel of depth image into occlusion boundary point or non-occlusion boundary point. The experimental results show that, compared with the existing methods, the proposed approach has higher accuracy and better universality.
		2014 Vol. 35 (6): 569-573 [Abstract] ( 700 ) HTML (1 KB) PDF (1065 KB) ( 720 )

	574	Study on LED Total Spectral Radiant Flux Measurement Technology
		LIU Hui,ZHAO Wei-qiang,LIU Jian,LI Yi,ZHAO Hai-su
		DOI: 10.3969/j.issn.1000-1158.2014.06.11
		The theory and method of measuring total radiant flux and total spectral radiant flux is described. The components and character of a goniospectroradiometer had been introduced. Three kind of light sources have been measured, the measurement uncertainty is 1.6%~3.6%(k=2). Luminous flux calculated by the spectra radiant flux comparison with NIM′s photometric based luminous flux scale shows that agreement is within 0.9%, well within the combined measurement uncertainty.
		2014 Vol. 35 (6): 574-577 [Abstract] ( 669 ) HTML (1 KB) PDF (500 KB) ( 940 )

	578	Correcting Effective Radiance Temperature Measurement for Emissivity Effect
		YUAN Zun-dong,XING Bo,BAI Cheng-yu,FU Cheng-yu,CHEN Gui-sheng
		DOI: 10.3969/j.issn.1000-1158.2014.06.12
		The classical correction model with the Wien and ambient-radiation-less approximations is not suitable for emissivity correction and uncertainty evaluation middle and low temperature infrared thermometry.The effective radiance temperature concept is adopted to obtain the emissivity effect model, with wide validity for measured temperature and measuring wavelength and its differential form with obvious physical meanings.The error using the classical correction model is discussed under the middle and low temperature measurements.The emissivity correction methods are described under different blackbody radiator traceable approaches in radiation thermometer calibration, and an example is given.The method discussed is suitable for the emissivity and reflected ambient radiation corrections and associated uncertainties calculations in the applications and calibrations of radiation thermometers and blackbody radiators.
		2014 Vol. 35 (6): 578-582 [Abstract] ( 713 ) HTML (1 KB) PDF (313 KB) ( 922 )

	583	China Academy of Aerospace Aerodynamics, Beijing 10074, China
		XU Kao,CHEN Lian-zhong,YANG Zhong-kai
		DOI: 10.3969/j.issn.1000-1158.2014.06.13
		Heat flux measurements for three types of calorimeters are compared in the turbulent conduit. The three types of calorimeters are the slug with an insulator(the first type), the heated end brim of slug touching the test article by points (the second type) and 0.4 mm gap between the heated end brim of slug and the test article (the third type) respectively. These calorimeters are uniformly installed on the test article with the length and width of 100 mm ×100 mm to measure the heat flux values. The results show that under low pressures and small heat flux conditions, the measurement values of three types of calorimeters match well; Instead, under high pressures and larger heat flux conditions, the measurement value of the third is the most and that of the second is the lowest; Meantime, as with the decrease of pressures in the turbulent conduit, the measurement values of the third are close to those of the second little by little.
		2014 Vol. 35 (6): 583-587 [Abstract] ( 603 ) HTML (1 KB) PDF (2058 KB) ( 488 )

	588	Experimental Research on the Effect of Measuring Distance on Calibration Results of Radiation Thermometers
		LUAN Hai-feng,WANG Zheng
		DOI: 10.3969/j.issn.1000-1158.2014.06.14
		Aiming at the effect of measuring distance on calibration results of radiation thermometers, the experimental research was carried out. Both testing data and analytical charts for the several conventional radiation thermometers chosen are shown. The optimal measuring distance of radiation thermometer is defined, which is in the range of 0.3~0.5m to be away from the target surface of blackbody radiation source.
		2014 Vol. 35 (6): 588-590 [Abstract] ( 676 ) HTML (1 KB) PDF (318 KB) ( 557 )

	591	Realization for the Secondary Standard of Density
		LUO Zhi-yong,LI Zhan-hong
		DOI: 10.3969/j.issn.1000-1158.2014.06.15
		he basic principle, apparatus, procedure and parameters by the method of hydrostatic weighing was introduced. With the hydrostatic weighing, the density dessimination from the solid density primary standard—silicon sphere to the second primary standard—a group of 137 hydrometers has been realized. The measuring uncertainty in full range has been evaluated in detail.
		2014 Vol. 35 (6): 591-594 [Abstract] ( 721 ) HTML (1 KB) PDF (468 KB) ( 574 )

	595	Kinematical Calibration of Mass Property Measurement System
		WANG Chao,ZHANG Xiao-lin,TANG Wen-yan,WANG Jun,MA Qiang
		DOI: 10.3969/j.issn.1000-1158.2014.06.16
		In the process of measuring mass properties, the measurement of precision is influenced by position accuracy directly. The kinematics equation of the physical construction of the equipment is established with D-H transformation matrix. The relational equation between equipment terminal position error and link D-H parameter error is present. The calibration points position in different pose are measured with laser tracker, then the real D-H parameters are obtained by solving calibration equation, which is established by position error and Jacobian matrix. In the end, the calibrated results are verified by simulation. The result shows that positioning accuracy of the equipment is improved obviously through calibrating.
		2014 Vol. 35 (6): 595-598 [Abstract] ( 464 ) HTML (1 KB) PDF (958 KB) ( 594 )

	599	Study on Detection Method of Worm Tooth Profile Variation in Worm Reducer Based on Autocorrelation Algorithm
		ZHANG Rong-fa,HU Jia-cheng,LI Dong-sheng,WANG Jian,MA Hao
		DOI: 10.3969/j.issn.1000-1158.2014.06.17
		In order to diagnosis the fault of worm reducer caused by worm gear tooth profile changed, a new vibration signal detection method is proposed. The new method was that autocorrelation analysis was referenced to traditional gear fault analysis method which were empirical mode decomposition (EMD) and Hilbert transform. The worm reducer vibration signal were separated to different intrinsic mode functions component in different frequency (IMF). The autocorrelation analysis method is used to select IMF component which containing worm gear fault characteristic signal efficiently. Finally, the fault feature of IMF component is extracted by Hilbert transform. The JD45+ measuring instrument measuring the changed amount of worm gear tooth profile is used to verify the feasibility of this method.
		2014 Vol. 35 (6): 599-602 [Abstract] ( 616 ) HTML (1 KB) PDF (3112 KB) ( 580 )

	603	Experimental Investigation to Calibrate Pitot-tube by Laser Doppler Anemometer
		CUI Li-shui,HU He-ming,LI Chun-hui
		DOI: 10.3969/j.issn.1000-1158.2014.06.18
		Pitot -tube is widely used to measure the air velocity. The coefficient α must be calibrated to correct the measurement result.Laser Doppler anemometer can be applied to calibrate Pitot-tube to acquire the coefficient α. During the process, the calibration result can be influenced by the flow round the probe of Pitot-tube and air velocity distribution deviation in long axis. The experiments are conducted to evaluate or correct this influence. The results show the calibration results will be different due to the interference of probe mounted in flow field. For this reason the proper measurement position for laser doppler anemometer is required to reduce the influence as much as possible. The inherent air velocity distribution deviation also influences the calibration result of α. This influence can be corrected by actual measurement.
		2014 Vol. 35 (6): 603-606 [Abstract] ( 686 ) HTML (1 KB) PDF (437 KB) ( 581 )

	607	Edge Detection of the Defects in Ultrasonic C Scan Image Based on Morphology
		LV Jiang-ming,ZHENG Hui-feng,TANG Ting-hao,YU Sang-sang,YANG Chen-long
		DOI: 10.3969/j.issn.1000-1158.2014.06.19
		For the weak adaptation of noise interference and low computational efficiency of the edge detection algorithm based on traditional morphology,the adaptive edge detection algorithm based on multi-structure and morphology and the ratio of edge was proposed. The ultrasonic C scan image was divided into three kinds of different complexity image according to the edge level percentage. Then,different structure elements were adopted in edge detection based on morphology for different complexity ultrasonic C scan image. At last,the final edge was determined according to the information entropy of different edge images. Experimental results showed that the proposed algorithm not only have effectively eliminated the influence of noise and better retain the image detail,but also improved the efficiency and accuracy of the edge detection of the defects in ultrasonic C scan image.
		2014 Vol. 35 (6): 607-611 [Abstract] ( 586 ) HTML (1 KB) PDF (3055 KB) ( 536 )

	612	Ultrasonic Testing Based Multi-feature Extraction of UAV Composite Materials
		WANG Feng-lin,WANG Chang-long,HU Yong-jiang
		DOI: 10.3969/j.issn.1000-1158.2014.06.20
		Due to the single feature extraction has not exert information as well as different features have different importance while recognizing UAV composite materials flaws, a method for multi-feature extraction in wavelet packet field and time-field is proposed. The new approach firstly decomposes signal with wavelet packet to get feature, using principal component analysis to decrease the dimension of feature vectors, then, extracts time-field feature considering composite materials characters. at last, the combined feature vectors algorithm is proposed using the matching method. The experimental results indicate the effectiveness of the proposed feature vectors while classifying the bond flaws in composite materials.
		2014 Vol. 35 (6): 612-616 [Abstract] ( 679 ) HTML (1 KB) PDF (3973 KB) ( 662 )

	617	Test for the End-corner Reflection of Ultrasonic
		LING Li-gong
		DOI: 10.3969/j.issn.1000-1158.2014.06.21
		The end-corner reflection test system is built basing on Z-scan ultrasonic detector, standards and reference blocks,as well as UltraVision ultrasonic signal acquisition and analysis software. Respectively, the end-corner reflection of 45°、60°and 70°Ultrasonic transducers is tested. First, all reflection echo signal are sampled and analysed, and then the end-corner reflection echo signals is isolated basing on ultrasonic propagation law and the end-corner reflection waves mode conversion law. The relative reflectance of the above signal is computed at last. Test results show that 45 °transverse wave transducer end-corner reflection close to the total reflection. The clutter from the end-corner reflection of longitudinal wave transducer is more than the transverse wave transducer.
		2014 Vol. 35 (6): 617-620 [Abstract] ( 755 ) HTML (1 KB) PDF (1360 KB) ( 664 )

	621	Study on Atmospheric PM2.5 Soft Sensor Based on GA-BP Neural Network
		ZHENG Hai-ming,SHANG Xiao-xiao
		DOI: 10.3969/j.issn.1000-1158.2014.06.22
		Because of the varying concentration of atmospheric PM2.5 have strong nonlinear characteristics, traditional soft sensor methods are difficult to make accurate measuring and monitoring. According to traditional BP neural network is easy to fall into local minimum, BP neural network is combined with genetic algorithm to establish the GA-BP neural network soft sensor model. The model is applied to the monitoring of the atmospheric concentration of PM2.5, and compared with the results of the monitoring of the traditional BP neural network model, the results show that the genetic algorithm optimization model has a better non-linear fitting ability and higher monitoring accuracy.
		2014 Vol. 35 (6): 621-625 [Abstract] ( 807 ) HTML (1 KB) PDF (1604 KB) ( 702 )

	626	Modeling and Optimization of NO_x for Coal-fired Boilers by Free Search Algorithm and Support Vector Machine
		NIU Pei-feng,WANG Pei-kun,LI Guo-qiang,MA Yun-fei,CHEN Gui-lin,ZHANG Xian-chen
		DOI: 10.3969/j.issn.1000-1158.2014.06.23
		A model of the boilers NO_x emissions is developed by support vector machine (SVM). The free search (FS) algorithm is used to optimize the parameters of the SVM model and the input parameters of the boilers. The modeling results show that, FS-SVM model can predict NO_x emissions very well, the forecast accuracy is very high.NO_x emissions are significantly reduced by optimizing the input parameters, and the change of the optimized parameters are consistent with the experimental results of the related reference.
		2014 Vol. 35 (6): 626-630 [Abstract] ( 631 ) HTML (1 KB) PDF (1501 KB) ( 561 )

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