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2018 Vol. 39, No. 6 Published: 2018-11-22

	753	Joule Balance Alignment Energy Error Evaluation by Horizontal Ampere Force and Electromagnetic Torque
		ZENG Tao,LU Yun-feng,LI Zheng-kun,ZHANG Zhong-hua,CHEN Le,CHEN Xiao-ming
		DOI: 10.3969/j.issn.1000-1158.2018.06.01
		Based on the principle of the joule balance method, the generating mechanism of the misalignment situation of the characteristic vectors on the suspended coil was studied, and the coupling influence between the horizontal ampere force and electromagnetic torque was analyzed, thus the principle of the influence on the alignment error by the horizontal force and torque was revealed. The decoupling structure based on two flexure hinge was designed to decouple the horizontal force and torque in the range of action, and the solving models for the force and torque were also established based on the torque-balance-principle. Finally, the relative alignment error caused by the horizontal ampere force and the electromagnetic torque was evaluated to be approximately 1×10^{-6 based on the solving models.}
		2018 Vol. 39 (6): 753-758 [Abstract] ( 437 ) HTML (65 KB) PDF (1498 KB) ( 385 )

	759	Further Discussion on Characteristics of Staircase Waveform
		LU Zu-liang,YANG Yan,HUANG Lu,WANG Lei
		DOI: 10.3969/j.issn.1000-1158.2018.06.02
		Staircase waveform is a bridge from DC to AC measurement, and will be a potential bridge from static to dynamic state. Based on classification of sinusoidal type staircase waveforms their characteristics are researched. Combining a figure and an infinite series, the special aliasing effect with staircase waveform is analyzed, in which the parameter is extended from positive integer to real number, and relevant physical meanings and their properties are pointed out. These characteristics of the staircase waveform will provide an important basis for their metrology application.
		2018 Vol. 39 (6): 759-767 [Abstract] ( 441 ) HTML (1 KB) PDF (822 KB) ( 390 )

	768	Measurement and Analysis of Impedance Frequency Characteristics of Fe-Ga Alloy
		WENG Ling,LIANG Shu-zhi,LI Wei-na,HUANG Wen-mei,WANG Bo-wen
		DOI: 10.3969/j.issn.1000-1158.2018.06.03
		The softening coefficient (S33) and the magnetic mechanical coupling coefficient (K33) of Fe-Ga alloy were determined by measuring the impedance frequency characteristics of Fe-Ga under different magnetic fields, which provides a design reference for the application of Fe-Ga alloys in systems such as actuators and transducers.The resonant frequency and the anti-resonant frequency of the rod-shaped sample and the flake sample under different magnetic fields were measured by constructing the measuring device.The calculation of S33 and K33 were carried out and the characteristic parameters of the flake sample and the rod sample were compared and analyzed.The results show that S33 and K33 of rod sample and the flake sample increase first and then decrease with the increase of the magnetic field.The softening coefficient of the flake sample is smaller than that of the rod sample, and the magnetic mechanical coupling coefficient is larger than that of the rod sample.
		2018 Vol. 39 (6): 768-770 [Abstract] ( 374 ) HTML (1 KB) PDF (748 KB) ( 265 )

	771	Experimental Research on the Control and Non-linear Calibration of Large-scale Two-dimensional Nanometer Displacement Stage
		ZHOU Qi,LIU Bing-feng,LIAN Xiao-yi,CHEN Ben-yong,HUANG Lu,LI Qi,GAO Si-tian
		DOI: 10.3969/j.issn.1000-1158.2018.06.04
		To study the control and non-linear correction of a large-scale two-dimensional nanometer displacement stage, a micro-displacement measurement system which based on the measurement principle of a laser interferometer was setted up.The composition of the dual-frequency laser interferometer measurement system was introduced, the control program of nanometer displacement stage and data acquisition program of laser interferometer were programmed. The non-linear calibration method was described, the polynomial third-order fitting and the third-order were compared through experiments. Experiments show that the calibration method using third-order piecewise fitting is better than third-order. Before calibration, the maximum nonlinearity error of x-axis and y-axis is 4.052 μm and 2.927 μm. After calibration, the maximum non-linearity of the x-axis is 15 nm and the maximum nonlinearity error of the y-axis is 17 nm, which is only 1% of the original nonlinearity error.
		2018 Vol. 39 (6): 771-776 [Abstract] ( 391 ) HTML (1 KB) PDF (2394 KB) ( 646 )

	777	Large Surface Measurement Method of Effectively Eliminating Multi-view Stitching Accumulative Error
		SHAO Wei,PENG Peng,ZHOU A-wei,GAO Rui-peng
		DOI: 10.3969/j.issn.1000-1158.2018.06.05
		For the purpose of improving the accuracy of measuring large-sized curved surfaces, precision machines, photoelectric technology, CAD/CAM/CAT and automatic control technology are employed comprehensively, and high-precision measuring equipment and numerically controlled processing equipment are combined to realize the integration of on-line inspection and processing of large-sized curved surfaces. According to a detailed analysis of factors that affect the precision of splicing sub-contours of a multi-view sequence, both a contour splicing strategy based on mutual reference and a splicing method based on integral error compensation are proposed to diminish the effect of accumulative errors resulting from multi-view splicing. Subsequently, quadratic assignment of accumulative errors is achieved in line with the principle that the closed continuous splicing error of contours is zero in the end, thus reducing the accumulative errors resulting from continuous splicing of sequential contour data. The results show that the accuracy of this system is higher than 20μm.
		2018 Vol. 39 (6): 777-782 [Abstract] ( 407 ) HTML (1 KB) PDF (1704 KB) ( 323 )

	783	Study on Characterization Parameters of Aggregate Particle Size Using Image Analysis
		ZHOU Jian-hua,FANG Huai-ying,YANG Jian-hong,CHEN Si-jia,LUO Man
		DOI: 10.3969/j.issn.1000-1158.2018.06.06
		In image detection method of aggregate size, aggregate size characterization parameters are important factors influencing the result of size distribution. The developed aggregate size detection system based on image method consists of LED light source, industrial CCD camera and LabVIEW software platform. Different equivalent diameters are used to grade aggregate particle size, and different equivalent volumes are used to calculate aggregate quality. The difference aggregate size distribution results calculated from different equivalent diameters and different equivalent volumes are compared. In order to make the image detection useful for actual production, and convenient for production line staff to observe, a set of image size parameters matching screening method are obtained.The result shows that Minor Axis (Feret) could be used as equivalent diameter, while equivalent volume obtained by projected area×Minor Axis (Feret) has max-relativity with actual volume.
		2018 Vol. 39 (6): 783-790 [Abstract] ( 350 ) HTML (1 KB) PDF (2299 KB) ( 674 )

	791	The Influence of Temperature on Interlayer Coupling of Stacking Bilayer Graphene
		SHENG Xiang-yong,REN Ling-ling,YAO Ya-xuan,YU Sheng-wang
		DOI: 10.3969/j.issn.1000-1158.2018.06.07
		Interlayer coupling of stacking graphene and chemical vapor deposition grown (CVD-grown) graphene with different layers was analyzed using Raman spectroscopy at room temperature. Then bilayer graphene prepared by random stacking and CVD-grown were selected to study the influence of temperature on interlayer coupling. The results showed that the interlayer coupling between stacking bilayer graphene and CVD-grown bilayer graphene were different, there is none or weak coupled interaction in stacking bilayer graphene while CVD-grown bilayer graphene has stronger coupled interaction between layers. For G peak frequency, stacking bilayer graphene exhibits a lower value of thermal coefficient compared to CVD-grown bilayer graphene when the temperature increased from 25 ℃ to 250 ℃. When the temperature was higher than 250 ℃, a positive value of thermal coefficient of stacking bilayer graphene was observed, which indicated the occurrence of coupled interaction between the layers. Additionally, similar trends were observed for full width at half-maximum of the 2D peak and the intensity ratios of G and 2D peaks (IG/I2D) of these two materials over the temperature range of 25 ℃ to 400 ℃. Moreover, stacking bilayer graphene is more sensitive to temperature change compared to CVD-grown bilayer graphene.
		2018 Vol. 39 (6): 791-796 [Abstract] ( 410 ) HTML (1 KB) PDF (2236 KB) ( 634 )

	797	Research on a Novel Hall Angle Sensor
		ZHAO Hao,FENG Hao,DING Li-jun,CHENG Hai-yu
		DOI: 10.3969/j.issn.1000-1158.2018.06.08
		A new Hall angle sensor is designed, the mechanical structure and working principle of sensor are introduced in detail, and the output characteristics of the sensor are deduced according to magnetic circuit law and Hall effect, the derived results show that the sensor output Hall potential is proportional to the input angle, and there is no zero voltage for the output voltage of Hall sensor is differential. The finite element model of sensor is established, the magnetic field of sensor when in working are simulated, and the sensor measurement principle is verified. Finally, the output characteristics of sensor are measured, the experimental results show that the sensitivity of the sensor is about 105 mV/(°), the linear error is about 0.12%, the repeatability error is about 0.19%.
		2018 Vol. 39 (6): 797-800 [Abstract] ( 476 ) HTML (1 KB) PDF (1305 KB) ( 721 )

	801	Equal Proportion Offset Quantitative Collimator in Application of Laser Interferometer
		LIU Hong-guang,LU Rui-jun,LI Qing,LI Ling-mei,LI Yuan-yao,CHEN Jie
		DOI: 10.3969/j.issn.1000-1158.2018.06.09
		An equal proportion offset quantitative collimator in application of the laser interferometer is designed.The inspectors can conveniently and quickly and precisely measure the light path and adjust the light path at one time. Taking a 6m CMM positioning error as an example, the method of collimating the light path based on the quantitative adjustment of the proportional offset only needs to be adjusted once and spend time is less than 2 min.
		2018 Vol. 39 (6): 801-803 [Abstract] ( 329 ) HTML (1 KB) PDF (937 KB) ( 353 )

	804	Design of Automatic Judgment System of Answer Card Based on Vision
		CHENG Shu-hong,SHANG Guo-chao
		DOI: 10.3969/j.issn.1000-1158.2018.06.10
		Aiming at the limitation of function and price of cursor reader in the current market, a new method of answer cards recognition based on digital image processing is proposed. Firstly, the answer card is used for image pre-processing and graphic correction and the YCbCr color space algorithm is used to split out the candidate information area and answer information area. Then, the character matching and vertical synchronization-strips are used to locate their specific coordinates.Finally, the adaptive threshold algorithm is used to binarize the answer card and calculate the each filling area in binary image. Comparing the area with the set threshold, if it is bigger than set threshold, it will be regarded as having been filled. Experiments show that the method has higher recognition speed and accuracy. What’s more, it is not sensitive to the tilt of answer cards when scanning, and it has a better recognition effect on the size of the filling area, the unbalanced paintings, and the slight stains on answer cards, etc.
		2018 Vol. 39 (6): 804-810 [Abstract] ( 403 ) HTML (1 KB) PDF (5241 KB) ( 688 )

	811	Phase Contrast Filtering Model Based on X-ray Image Intensifier Imaging
		WANG He,MU Yi-ning,ZHANG Peng-fei,ZHANG Lu
		DOI: 10.3969/j.issn.1000-1158.2018.06.11
		The image acquisitions for the gratings made of aluminum, brass and stainless steel under different conditions of doses and thicknesses were carried out, combined with the system-level joint modulation evaluation model, the modulation effects of different materials on X-ray were studied, under the same radiation dose, no matter which kind of material was used, the difference in thickness is larger the imaging contrast is larger, in the case of the same thickness difference, the variation of the modulation ability of different materials with the radiation varies greatly with the change of the radiation dose. Three-dimensional curve fitting of optical modulation transfer function, X-ray dose and grating thickness difference was established, and the modulation model and acquisition model of the material on X-ray were established. A X-ray phase-contrast enhancement filtering model was proposed based on the image intensifier imaging model, in the noise environment, the integration filtering and phase contrast enhancement processing were performed, the image noise was suppressed while the target contour information was strengthened, and the contrast of X-ray images was greatly enhanced.
		2018 Vol. 39 (6): 811-815 [Abstract] ( 348 ) HTML (1 KB) PDF (2078 KB) ( 283 )

	816	Research on Extrapolation and Interpolation of Temperature Scale Deviation Equation over the Temperature -38.8344~156.5985℃
		WANG Ying-wen, ZHANG Xin, SUN Jian-ping, ZHENG Kun-can, DIAO Fu-guang, GAO Kai
		DOI: 10.3969/j.issn.1000-1158.2018.06.12
		The extrapolation for the deviation equation of two sub-ranges of 0~29.7646℃ and -38.8344~29.7646℃defined by the ITS-90 were derived and discussed, and a deviation equation was developed over the temperature range from -38.8344~156.5985℃. The feasibility of the extrapolation and the deviation equation were checked respectively with the calibration data from 15 and 23 standard platinum resistance thermometers. The results show that the maximum temperature difference between the extrapolation value and the temperature scale calculation result is less than 1.1mK when the deviation equation defined over the temperature range from 0℃ to 29.7646℃ extends to 100℃ and less than 2.6mK when extrapolating to -80℃ for the deviation equation defined over the temperature range from -38.8344℃ to 29.7646℃. The new quadratic deviation equation is equivalent to the deviation equation defined by ITS-90 within 1.5mK. So the extrapolation for the deviation equation of two sub-ranges and the new quadratic deviation equation are feasible to a certain extent.
		2018 Vol. 39 (6): 816-821 [Abstract] ( 505 ) HTML (1 KB) PDF (849 KB) ( 417 )

	822	Determination the Temperature Coefficient of Karma ResistorUsed in the Impulse Divider High Voltage Arm
		PAN Yang,ZHOU Li-ren,XU Feng,QIN Yi,ZHAO Ye-ming,PAN Jin-qiu,SHAO Hai-ming
		DOI: 10.3969/j.issn.1000-1158.2018.06.13
		The Karma resistor, which is used in the high-voltage arm of the high-voltage impulse divider, needs to be uniformly wrapped around the insulating skeleton. However, the introduction of the skeleton will affect the temperature coefficient of Karma resistor. Two dominant factors which affect the temperature coefficient are demonstrated, one is the thermo expansion coefficient of skeleton, the other is the bending strain caused by geometry structure of the skeleton. When the thermal expansion coefficient of the skeleton is larger than that of the material itself, the measurement result of the temperature coefficient will be larger than the true temperature coefficient of the resistance, bending strain will cause the destruction of the K-state structure and make the resistance value decrease.
		2018 Vol. 39 (6): 822-825 [Abstract] ( 365 ) HTML (1 KB) PDF (799 KB) ( 432 )

	826	Temperature Drift Compensation Method for Electronic Analytical Balance Based on Support Vector Machine
		LIU Ya-kun,HUANG Qiang,LI Jian-min,SUN Biao
		DOI: 10.3969/j.issn.1000-1158.2018.06.14
		The temperature sensitivity of the key components such as the electromagnetic force compensation cell is the main factor causing the temperature drift in the electronic analytical balance. In order to eliminate the error caused by the temperature drift, a model and compensation method for electronic analytical balance were proposed based on the support vector machine. Through analyzing the factors of the temperature drift, the temperature rise of the temperature sensitive element and the temperature drift data of the electronic analytical balance were taken as the inputs of the model, the adaptive parameter optimization method was used to search the optimal parameter, the temperature drift error model of electronic analytical balance was established and the temperature drift compensation was performed. The test results demonstrate that the absolute value of the full load indication error of electronic analytical balance, of which the range is 200g and the resolution is 0.1mg, not more than 0.3mg, that the indication error caused by temperature drift is superior to the impact index of the 1st class balance defined by Chinese National Standard GB/T 26497—2011 “Electronic balance”.
		2018 Vol. 39 (6): 826-831 [Abstract] ( 402 ) HTML (1 KB) PDF (1238 KB) ( 587 )

	832	Design and Implementation of Solid Density Balance Calibration System
		CHEN Chao-yun,ZHANG Jin-ming,REN Xue-di
		DOI: 10.3969/j.issn.1000-1158.2018.06.15
		In view of the fact that the density balance can only be calibrated in the liquid mode and can not be calibrated in the solid mode, a kind of hook-type cavity glass weight is developed as solid density standard, the density balance solid measurement mode is calibrated, and a solid density balance calibration system is proposed. Calibration experiments on solid density balance show that the expanded uncertainty of the calibration results is 0.0016g/cm3 (k=2).
		2018 Vol. 39 (6): 832-835 [Abstract] ( 359 ) HTML (1 KB) PDF (481 KB) ( 324 )

	836	Calibration Method of Strain Sensor Metrological Characteristics
		YUAN Xing-qi,CHEN Kai,CUI Jian-jun,YAN Yong-gang,SHU Hong-lin,SHEN Xue-ping
		DOI: 10.3969/j.issn.1000-1158.2018.06.16
		In order to evaluate the metrological characteristics of strain sensor (strain gauge) reasonably, the differences of the metrological characteristics in the relevant national standards and technical specifications of the strain gauge were analyzed, and the vibrating wire strain gauge was taken as an example to sum up the metrological characteristic parameters of the strain gauge. The existing status quo of strain gauge calibration was studied, and a high precision calibration device based on laser interferometry was designed, whose gauge range could reach 500 mm. Then a set of high-precision calculation methods of metrological characteristics was proposed. The characteristics of the strain sensor were tested by experiments, and the uncertainty of the calibration of the integrated error U=0.10% (including factor k=2) was evaluated.
		2018 Vol. 39 (6): 836-841 [Abstract] ( 421 ) HTML (1 KB) PDF (571 KB) ( 1080 )

	842	Drilling-ability Evaluation for Grey Cast Iron and Ductile Iron Front Brackets
		REN Feng-zhang,CUI Lin-kai,SHI Wen-ping,XIONG Yi,WEI Shi-zhong
		DOI: 10.3969/j.issn.1000-1158.2018.06.17
		The drilling-ability of HT250 and QT450 used in front brackets of tractors has been evaluated in terms of thermal conductivity, chip shape, surface roughness in the drill hole, temperature of drill top and drilling load (torque, feeding force). The relationship between the drilling-ability and microstructure is analyzed. Experimental results show that drilling load of two front brackets was roughly same. Compared with the HT250 tractor front bracket, the one of QT450 has a larger surface roughness in the drill hole and a higher temperature of drill top. This is mainly because QT450 has a weaker graphite segmentation effect to matrix and a higher ferrite content, there is certain difficulty in chip breaking and chip removal during drilling, which leads to the larger surface roughness in the drill hole of QT450. The smaller heat conductivity coefficient and severer friction between the drill and chip result in the higher temperature of drill top. Moreover, QT450 has a smaller cutting force and a larger friction force between the drill and chip. Under the comprehensive function of the two forces, QT450 has nearly the same drilling load as HT250.
		2018 Vol. 39 (6): 842-846 [Abstract] ( 360 ) HTML (1 KB) PDF (1209 KB) ( 476 )

	847	Intelligent Detection Method of Variable Load Gearbox Fault Signal
		SHI Pei-ming,ZHAO Na,SU Guan-hua,SONG Tao,HAN Dong
		DOI: 10.3969/j.issn.1000-1158.2018.06.18
		Aiming at the problem of gear fault feature extraction and classification under variable load excitation, an intelligent detection method of gearbox based on empirical mode decomposition (EMD) and deep belief network (DBN) is presented. Therefore, the intrinsic mode function (IMF) of the meshing frequency and the frequency doubling is selected to reconstruct the signal, and obtain the spectrum of the reconstructed signal, which is the input of the deep belief network. In the deep belief network, the pre-training and feature learning of input spectrum are carried out, and the classification model of gear fault recognition based on variable load excitation is established. Finally, fault diagnosis is carried out by using the constructed deep belief network. The experimental results show that the proposed method can effectively identify gear failure types under variable load excitation.
		2018 Vol. 39 (6): 847-851 [Abstract] ( 398 ) HTML (1 KB) PDF (687 KB) ( 339 )

	852	Rapid Volume Measurement for Oil Tank Displacement Based on 3D Laser Scanning and Convex Hull Algorithm
		ZHUANG Zheng-jie,WANG Li-guang,GONG Ying-zhong, GUAN Liang,XU Jun-tian
		DOI: 10.3969/j.issn.1000-1158.2018.06.19
		A rapid volume measurement method for vertical oil tank bottom displacement was proposed to overcome the shortcomings of traditional methods in low accuracy and low repeatability. The 3D point cloud data via 3D laser scanner was used as the study object. The 3D convex hulls construction algorithm based on computational geometry was used to form a 3D convex hull. Then calculate its volume by projection method. In order to verify the accuracy of the rapid method, a vertical oil tank was selected for test,the repetitive error 10 measurements is 1.28%. Then measure it with traditional method,the repetitive error is 11.81%. The relative deviation of two methods was 7.43%.
		2018 Vol. 39 (6): 852-856 [Abstract] ( 423 ) HTML (1 KB) PDF (914 KB) ( 531 )

	857	Establishment and Research of A New Model for Measuring Breathing Loss in Oil Tank
		LIANG Ying
		DOI: 10.3969/j.issn.1000-1158.2018.06.20
		To establish the numerical model for calculating the air loss during the period of static storage, loading, offloading of oil in tanks, the initial and final temperature during the period of emissions was estimated, and vapor pressure of oil product was considered. Based on Fick spreading law, continuity equation and distribution characteristics of oil-gas in actual tanks, it is capable of getting oil-gas concentration model.According to the logical relationship between air loss and concentration of oil-gas, actual amount of breathing loss could be get. Compared with the measured data, it is confirmed that the concentration model and the air volume measurement method are reliable, and the average error of the newly constructed model is about 38% of other models..
		2018 Vol. 39 (6): 857-861 [Abstract] ( 386 ) HTML (1 KB) PDF (763 KB) ( 373 )

	862	Application of Robust Statistics and Grubbs Criterion in Proficiency Testing Results Analysis
		YANG Jin-yan,JIANG Zeng-jie,CHEN Wei
		DOI: 10.3969/j.issn.1000-1158.2018.06.21
		The data of the 6 groups of hot rolled ribbed bar were analyzed respectively using robust statistics of four quantile, robust statistics with iterative method, classical statistical method . The results show that the data of Z in the data set is larger than 5, which is outlier, The data are subject to or close to the normal distribution, the results of the three statistical methods are basically consistent;if there is no outlier data, it is recommended to use robust statistical method (four quantile method or iterative method) for statistical analysis; If there is outlier data, the Grubbs criterion should be used to eliminate the outliers and the classical statistical method should be used for statistics; The data significantly deviate from the normal distribution, if there is no outlier data, it is recommended to use iterative method for statistical analysis; If there is outlier data, the Grubbs criterion should be used to eliminate the outliers and the classical statistical method should be used for statistics.
		2018 Vol. 39 (6): 862-867 [Abstract] ( 425 ) HTML (1 KB) PDF (1022 KB) ( 733 )

	868	Fusion Method of Ultrasonic Gas Flowmeter Based on Kalman Filter
		LIU Bo,XU Ke-jun,MU Li-bin,TIAN Lei,SHEN Zi-wen,LI Jian-bo
		DOI: 10.3969/j.issn.1000-1158.2018.06.22
		Aiming at the problem of how to integrate multiple traffic results from multiple channels in gas ultrasonic flowmeter, a fusion method based on Kalman filter is proposed. The multichannel ultrasonic gas flowmeter is considered to be a combination of several mono flow meters. According to the statistical rule of each channel calculation result, the weight coefficient of the flow result of each channel in the final output is automatically adjusted, The fusion method consumes less computational resources to achieve the judgment and processing of the outliers in the flow results, so that the flow output more stable. The algorithm is realized in real time on the ultrasonic gas flowmeter signal processing system with DSP and FPGA as the core. And real flow experimental results demonstrate the effectiveness of the method.
		2018 Vol. 39 (6): 868-873 [Abstract] ( 432 ) HTML (1 KB) PDF (799 KB) ( 286 )

	874	Study and Establishment of the Mathematical Model of the Standard Volume of the Bell Prover
		LIU Chen-kui,QU Hong-qiang,CHEN Shi-yan,XING Jing-fang,NIU Li-na,HUI Ji
		DOI: 10.3969/j.issn.1000-1158.2018.06.23
		The characteristic of bell prover’s height and radius is qualitatively analyzed by the dot diagram based on the measured datas, the establishment of mathematical model by Fourier series is proposed, the ideal function is obtained by using Matlab and the fitting standard deviation is analyzed. In practical application, the descending height of the bell prover is measured by grating rulers, the function is integrated by using principle of definite integral to obtain the volume value of the gas discharged by the bell prover, at the bottom of the instantaneous flow, the expansion uncertainty of the standard volume is 4×10-4(k=2), which decreases by 66.7 % relative to the method of estimation based on mean radius, simultaneously, starting and stopping at any point of the bell prover during the test is implemented.
		2018 Vol. 39 (6): 874-877 [Abstract] ( 416 ) HTML (1 KB) PDF (424 KB) ( 266 )

	878	Ultrasonic B Image Defect Segmentation Method Based on Automatic Seeded Region Growing
		NI Hao,ZHENG Hui-feng,WANG Yue-bing,HU Liu-chen,CAO Yong-gang,ZHANG Kai
		DOI: 10.3969/j.issn.1000-1158.2018.06.24
		An ultrasound image defect segmentation algorithm based on automatic seeded region growing was proposed. First, the pre-segmentation of the ultrasound B image was performed by the Otsu method. Next, the seed starting points were set automatically by seeking the absolute background area. Then, the defects were segmented from the background area by regional growth algorithms. Finally, the defect recognition was further improved by digital morphological noise reduction method. Experimental results shown that the defects were segmented effectively by the proposed algorithm and good defect boundary information has also been provided. The efficiency of processing ultrasonic B images is improved and noise of B-scan image is mostly suppressed effectively.
		2018 Vol. 39 (6): 878-883 [Abstract] ( 351 ) HTML (1 KB) PDF (1835 KB) ( 610 )

	884	A Calculating Method of the Acoustic Field about High Frequency Transducers
		XIONG Jiu-peng,WANG Yue-bing,ZHAO Peng
		DOI: 10.3969/j.issn.1000-1158.2018.06.25
		Based on the twovdimensional space Rayleigh integral and the two-dimensional planar sound pressure construction technique, a sound field calculation method of a high frequency transducer was proposed. In order to verify the correctness of the method, the acoustic field of a rectangular piston transducer with 4 piezoelectric components and 1.8 MHz was tested and calculated to obtain the sound pressure distribution at different distances. At 50 cm, the maximum error of the calculation is 8.25%. On the premise of guaranteeing the accuracy, the method effectively improves the sound field measurement efficiency of high frequency transducers.
		2018 Vol. 39 (6): 884-887 [Abstract] ( 344 ) HTML (1 KB) PDF (876 KB) ( 433 )

	888	The Measurement Uncertainty of Curve-fit Parameters of Sinusoidal
		LIANG Zhi-guo
		DOI: 10.3969/j.issn.1000-1158.2018.06.26
		It is described that the uncertainty of evaluation results of sine wave parameters by using the least mean square four-parameter sine wave curve-fit method, including the courses of analysis and evaluation of uncertainty of it. Some error sources of curve-fit parameters are discussed, including the signal amplitude errors, the harmonic distortion of sampling serials, the quantization errors & noise & the spurious distortion, the jitter of the signal periods in sampling serials, the calculation errors of software, and the others. The Uncertainty of curve-fit parameters is given out, and several main methods about decreasing the curve-fit parameter errors and evaluation uncertainty have been proposed. In an example of experiment, that the analysis and uncertainty evaluation results of amplitude of sine wave by using curve-fit method is presented.
		2018 Vol. 39 (6): 888-894 [Abstract] ( 341 ) HTML (1 KB) PDF (1082 KB) ( 718 )

	895	Gait phase recognition based on multi-source biological signals
		ZHANG Qi-zhong,XI Xu-gang,LUO Zhi-zeng
		DOI: 10.3969/j.issn.1000-1158.2018.06.27
		In order to improve the accuracy of gait recognition, the gait recognition of human lower limb was studied based on the fusion of surface electromyography (sEMG), knee joint angle and plantar pressure. Firstly, the sEMG signals were decomposed by wavelet packet to extract the features of multi-scale energy and multi scale fuzzy entropy. Then, the principal component analysis (PCA) method was employed to reduce the dimension of the feature value of sEMG, and the feature vectors were constituted by the features of sEMG, plantar pressure and the knee energy. Finally, the feature vectors were inputted into the least squares support vector machine (PSO-LSSVM) optimized by the particle swarm to recognize gait of lower limb. The experimental results show that this method has higher recognition accuracy and validity than other methods.
		2018 Vol. 39 (6): 895-901 [Abstract] ( 336 ) HTML (1 KB) PDF (1809 KB) ( 604 )

	902	Research of Cell Lysis Intelligent Monitoring and Counting System Based on the Improved Hough Algorithm
		JIANG Feng,LUO Li-ming,CHEN Jian-jun,YU Jun
		DOI: 10.3969/j.issn.1000-1158.2018.06.28
		In order to improve product yield and quality in the cell, based on machine vision technology, the traditional Hough image recognition algorithm and on the basis of the existing cell crushing plant was improved, proposes a project to intelligent monitoring cell broken counting system. This scheme uses optical amplification circuit and CCD image sensor circuit as hardware platform, which is assisted by machine vision technology and image processing algorithm to realize image monitoring and counting statistics of cell crushing process. Cell broken online experiment indicated that the intelligent monitoring and counting system can complete statistical counting of cells broken, and real-time capture of broken images. The recognition speed improves nearly 10 times compared with the standard Hough image recognition algorithm; it can be applied to automated extraction intracellular substances in cell.
		2018 Vol. 39 (6): 902-907 [Abstract] ( 337 ) HTML (1 KB) PDF (950 KB) ( 407 )

	908	Development of Impurity Reference Materials in High Purity Helium
		HU Shu-guo,ZHANG Ti-qiang
		DOI: 10.3969/j.issn.1000-1158.2018.06.29
		The gravimetric preparation process of trace impurities reference materials in high purity helium including hydrogen, neon, oxygen, argon, nitrogen, methane, monoxide carbon and dioxide carbon are introduced. The process includes technology of gravimetric method,quantity of relative impurity in dilution gas,stability test and etc. The amount-of-substance fraction range of eight kinds of trace impurities is between 0.5μmol/mol and 4.0μmol/mol and the expand uncertainty is between 1%~3%(k=2) according to national standard GB/T 4844—2011. The accuracy of value is verified by the international key comparison organized by CCQM. Comparing with current two-class reference materials, developed reference materials in the kinds and uncertainty keep ahead in domestic.
		2018 Vol. 39 (6): 908-913 [Abstract] ( 447 ) HTML (1 KB) PDF (847 KB) ( 496 )

	914	Evaluation of Uncertainty in Measurement of Cadmium in Immersion Solution of Ceramic Cartridge Faucets by ICP-MS
		CHEN Ren-jie,HUANG Ting-ting,LV Liang-yong, XIE Mei-mei
		DOI: 10.3969/j.issn.1000-1158.2018.06.30
		Cadmium in immersion solution of ceramic cartridge faucets was measured by ICP-MS. Established the mathematical model, according to JJF 1059.1—2012 "Evaluation and Expression of Uncertainty in Measurement". Analyzed and assessed the sources of uncertainty affecting factors, calculated the combined uncertainty and expanded uncertainty. The result showed that: when the Cadmium in immersion solution is 7.622μg/L and the confidence probability is 95%, the relative uncertainty is 3.2%;the greatest affecting factor is the standard curve fitting and the least affecting factor is the preparing of standard solution.
		2018 Vol. 39 (6): 914-917 [Abstract] ( 392 ) HTML (1 KB) PDF (329 KB) ( 465 )

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