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2017 Vol. 38, No. 4 Published: 2017-07-22

	385	A New Method of Aircraft Position and Pose Based on the Coincidence of the Symmetry Plane
		ZHANG Li,JIANG Chun
		DOI: 10.3969/j.issn.1000-1158.2017.04.01
		A method of calculating the pose of the fuselage based on the longitudinal symmetry was studied. The method combined the fuselage structure and the assembling process to extract the intersection point and key feature along the symmetry. The neutral plane was fitted and the first position and attitude adjustment vector were gotten. Based on the coincidence of the neutral plane, the fuselage adjustment saddle point programming model was proposed to distribute weight for each docking point according to the “max-min” principle. Through the application of assembling middle and rear fuselage, the validity of the method was verified.
		2017 Vol. 38 (4): 385-390 [Abstract] ( 666 ) HTML (1 KB) PDF (1072 KB) ( 546 )

	391	A Robust Gaussian Filtering Method in Surface Measurement Based on Gross Error Estimation
		XU Jing-bo,NIE Jia-li,WANG Sheng,XU Jin
		DOI: 10.3969/j.issn.1000-1158.2017.04.02
		A new robust filtering method for surface measurement is presented, which combines closely gross error estimation with Gaussian filtering method. Firstly, the abnormal signal is judged, identified and corrected by kσ criterion, and the corresponding algorithm is described in detail. Then Gaussian filter is designed through moving average approximation method to establish the mean line of surface profile. Finally, surface roughness profile is separated based on the original profile and the obtained mean line. The method has simple algorithm which is easy to realize, it can effectively restrain surface abnormal signal, and achieves robust filtering.
		2017 Vol. 38 (4): 391-395 [Abstract] ( 593 ) HTML (1 KB) PDF (1442 KB) ( 405 )

	396	Modeling and Analysis of Movement Error of Three Axis Orthogonal Robots
		ZHANG Xin-long,TIAN Guang-yu,HUANG Yong
		DOI: 10.3969/j.issn.1000-1158.2017.04.03
		The movement error model of three axis orthogonal robots was built based on homogeneous transformation. The relationship between the actual movement trace and target location was given. First perpendicularity error due to improper installation was included in the model. Then straightness, deflection angle and positioning error were taken into account. Finally elastic deformation was also calculated in the model. In addition, the methocl to acquire the needed parameter of the model was introduced, making it possible to calculate the movement trajectory of robots. Numerical simulations showed that the maximum movement error in x, y, z direction is 1.7 mm, 1.0 mm, 0.4 mm respectively. Experiments verified the effectiveness of the model and calculation.
		2017 Vol. 38 (4): 396-401 [Abstract] ( 603 ) HTML (1 KB) PDF (617 KB) ( 742 )

	402	Research on the Calibration Method of Key Parameters of Solar Simulator
		ZHANG Jun-chao,XIONG Li-min,MENG Hai-feng,HE Ying-wei,ZHANG Bi-feng
		DOI: 10.3969/j.issn.1000-1158.2017.04.04
		An on-line calibration method for the accuracy of electronic load of solar simulator was presented. The total IV curve could be calibrated. The electrical parameters (current, voltage and power) calibration device of the solar simulator was also set up. For optical parameters (non-uniformity and temporal instability) calibration device of the solar simulator, the influence of the temperature of detector and the resistance in series were investigated. The electric resistance should be less than 30 mΩ for the solar cell detector of 156 mm×156 mm size. The result of non-uniformity was consistent when the temperature of detector was steady during the measurement.
		2017 Vol. 38 (4): 402-405 [Abstract] ( 707 ) HTML (1 KB) PDF (437 KB) ( 549 )

	406	Stereo Matching Based on the Fusion of Color Segmentation and Weighted Non-parametric Transform
		CHEN Hua,ZHANG Zhi-juan,LIU Gang,WANG Shu-tao,ZHANG Yu-yan
		DOI: 10.3969/j.issn.1000-1158.2017.04.05
		Aiming at the limitations of the traditional non-parametric transformation, a stereo matching algorithm is proposed. One matching cost based on support region with arbitrary shape and size is obtained by using color segmentation information of the reference image, and another matching cost of weighted non-parametric transform in similar color region is obtained, then joint matching cost is obtained by the fusion of the both matching cost, and the dense disparity map is realized through the local optimization method. The experiment results show that the algorithm can improve the accuracy of the low texture, borders and occlusion regions. At the same time, it is robust against the amplitude distortion.
		2017 Vol. 38 (4): 406-409 [Abstract] ( 602 ) HTML (1 KB) PDF (709 KB) ( 421 )

	410	Study on 3D surface parameter evaluation method of ultra precision optical lenses
		WU Yi-wan,REN Zhi-ying,GAO Cheng-hui,LIN Jian-xing,JIANG Wei
		DOI: 10.3969/j.issn.1000-1158.2017.04.06
		The shortcomings of current ultra precision optical lens surface assessment methods is analysed. The existing optical elements surface characterization methods is embarked, combining with the three-dimensional surface parameters in the ISO25178-2. The relationship between the surface topography of optical lens and the corresponding optical properties is found out. The evaluation of the 3D surface of ultra precision optical lenses using the standard ISO is realized. The simulation results show that when the surface of the optical lens is highly subjectef to Gauss distribution, the transfer function of the optical system performance is evaluated with the decrease of the mean square value. And the example results show that the characteristics can also be well distinguished by the three dimensional parameters, and it has certain feasibility to characterize the optical surface by the use of the new comprehensive evaluation method.
		2017 Vol. 38 (4): 410-415 [Abstract] ( 606 ) HTML (1 KB) PDF (2480 KB) ( 1191 )

	416	Design and Reseach of Paper Counting Algorithem Based on Texture Image
		LIANG Hai-yi,WANG Ji-sen,LI Wen,SUN Ling-yuan
		DOI: 10.3969/j.issn.1000-1158.2017.04.07
		A paper counting algorithm based on the paper texture analysis is presented. The aim of the optimal design is to replace the manual paper counting with time-consuming and low precision, which collect the paper image with high precision image pickup device. To improve the speed of processing speed, Gauss filtering method was used to remove noise. Then directional filtering method and Gabor wavelet transform are combined to enhance the texture image. A counting correction algorithm is proposed according to the paper stack case, for the 0.3 mm stack of paper, the algorithm points to an accuracy rate is 100%, for the 0.2 mm stack of paper, the point of the accuracy rate is more than 99%. Test results show that the algorithm has good counting ability and high count accuracy.
		2017 Vol. 38 (4): 416-419 [Abstract] ( 712 ) HTML (1 KB) PDF (974 KB) ( 498 )

	420	The Diffraction Correction for Interferometric Absolute Gravimeters
		LI Chun-jian,SU Duo-wu,WU Shu-qing,FENG Jin-yang,XU Jin-yi
		DOI: 10.3969/j.issn.1000-1158.2017.04.08
		Based on the operating principle of an interferometric absolute gravimeter, a deviation of the measured gravitational acceleration value introduced by Gaussian laser beam is analyzed. And then a practical method, 90/10 knife-edge method, to measure the beam waist radius for diffraction correction is presented and the relative value of diffraction correction is obtained. Experimental results indicate that the beam waist radius is 1.1586mm and the relative value of diffraction correction is 7.56×10^-9. The solution to determine diffraction correction applies to every interferometric absolute gravimeter.
		2017 Vol. 38 (4): 420-423 [Abstract] ( 768 ) HTML (1 KB) PDF (333 KB) ( 499 )

	424	Calibrate of Ultra-low Frequency Acceleration by Mathematical Pendulum-vibration Generator Method
		HE Yi-cai,LIAO Jian-ping,ZHAO Jun-zhe
		DOI: 10.3969/j.issn.1000-1158.2017.04.09
		The calibration device of ultra-low frequency acceleration is established based on the mathematical pendulum-vibration generator. According to theory of low frequency noise, based on the spectral density function of laser interferometer, the method of quantitative evaluation for displacement noise is proposed. The validity of the proposed method is identified by experiment. The virtual pendulum-arm and excitation-transfer coefficient of mathematical pendulum-vibration generator is measured experimentally, the measurement uncertainty of the calibration device is evaluated. The accelerometers calibration of absolute method is realized, which is established in 0.001～0.1Hz frequency range, 5×10-7 ～0.01m/s2 acceleration range.
		2017 Vol. 38 (4): 424-428 [Abstract] ( 662 ) HTML (1 KB) PDF (335 KB) ( 514 )

	429	Prediction of the Creep of Piezoelectric Ceramic Based on BP Neural Network Optimized by Genetic Algorithm
		FAN Wei,LIN Yu-yang,LI Zhong-shen
		DOI: 10.3969/j.issn.1000-1158.2017.04.10
		The creep errors of the piezoelectric ceramics have nonlinear change with the time, which is difficult to revise in real time. A creep prediction approach based on back propagation neural network is proposed for the piezoelectric ceramics. The data is collected by the piezoelectric ceramic driving system and normalized for prediction. The parameters of BP neural network including the number of hidden layers, the number of nodes in each hidden layer, the node transfer functions and the training function are designed by experiments. The prediction model of BP neural network is established, and the connection between the creep of the piezoelectric ceramic and the time is built. The creep of piezoelectric ceramics is predicted by the model of BP neural network, compared with the measured data, the results show that, using this prediction model the maximal absolute error is below 0.1 μm, the maximal creep error is below 0.6% and the maximal mean square error is 0.0021. So the BP neural network prediction model has a high prediction accuracy and can be applied to the creep prediction of the piezoelectric ceramics.
		2017 Vol. 38 (4): 429-434 [Abstract] ( 755 ) HTML (1 KB) PDF (1452 KB) ( 930 )

	435	Research and Test of Automatic Calibration Method for Pressure Switch
		XU Zhi-ling,CHEN Wang-da,LIU Bao-qi,LI Zhi-fei,HU Lin-li
		DOI: 10.3969/j.issn.1000-1158.2017.04.11
		In order to solve the measurement error caused by the detection time delay of the pressure switch, an automatic calibration method is designed based on the comparison of the switching error of the pressure switch. According to the research on the mechanism of the automatic calibration of the pressure switch, a comparative model of the cycle approach is constructed, and the function relation between the switching error of the pressure switch and the rate of pressure change is determined. Using model scheme, the automatic calibration system is built. The closed loop feedback to adjust the rate of pressure change in real time is used, the switching value is obtained. The influence of pressure change rate and delay time is reduced in the calibration process by the automatic calibration method, and the experimental results show that the measurement accuracy is improved by 50%.
		2017 Vol. 38 (4): 435-438 [Abstract] ( 649 ) HTML (1 KB) PDF (544 KB) ( 445 )

	439	Bearing Fault Diagnosis Method Based on VMD and Generalized Fractal Dimension Matrix
		ZHANG Shu-qing, XING Ting-ting,HE Hong-mei,DONG Yu-lan, ZHANG Li-guo, JIANG Wan-lu
		DOI: 10.3969/j.issn.1000-1158.2017.04.12
		A method of bearing fault diagnosis based on variational mode decomposition (VMD) and generalized fractal dimension was proposed. A number of mode functions were obtained through the decomposition to the signal by VMD method. Then the generalized fractal dimension of each mode functions were calculated according to the different weighting factors, and arranged to construct the generalized fractal dimension matrix. Finally, according to the correlation coefficient of the signals generalized fractal dimension matrix and the sample signals, the fault status could be diagnosed. The experiment results showed that the method could extract fault feature accurately and stably, and distinguish signals of different status and identify the faults with close frequency.
		2017 Vol. 38 (4): 439-443 [Abstract] ( 707 ) HTML (1 KB) PDF (1220 KB) ( 538 )

	444	Research on Establishment and Control of a Constrained Complex Dynamic System Model
		FU Rong-rong, LI Dong-yu, SHI Pei-ming
		DOI: 10.3969/j.issn.1000-1158.2017.04.13
		A new constrained complex follow-up system-cup and ball pendulum system is proposed. To study control strategy of constrained dynamic system, this cup and ball pendulum system was chosen as study object. The system was modeled by Lagrange dynamics method. Controllability and observability of the system were studied firstly. Robust double closed-loop PID control and linear quadratic regulator optimal control based on genetic algorithm were used to achieve the experiment comparison. The comparative analysis results showed that robust double closed loop PID controller was of better robustness and transient characteristics, and linear quadratic regulator optimal controller based on genetic algorithm was of better dynamic characteristics.
		2017 Vol. 38 (4): 444-448 [Abstract] ( 598 ) HTML (1 KB) PDF (374 KB) ( 478 )

	449	Wind Power Gear Box Fault Diagnosis Based on DEMD Local Frequency Entropy and SVM
		MENG Zong,LIU Dong,YUE Jian-hui,ZHAN Xu-yang,MA Zhao,LI Jing
		DOI: 10.3969/j.issn.1000-1158.2017.04.14
		In order to extract the constituent of useful information from the nonlinear and non-stationary wind gearbox fault signal. A new approach for wind power gear box fault diagnosis based on the combination of differential-based empirical mode decomposition(DEMD), local frequency entropy and support vector machine(SVM) is proposed. Firstly, fault vibration signal is filtered with adaptive multi-scale mathematical morphology. Then mechanical vibration signal is decomposed with DEMD to obtain a certain number of intrinsic mode functions(IMF). Then the local time-frequency entropy of the IMF components are calculated and used as the eigenvectors of SVM. Finally, the eigenvectors are put into SVM to identify the state of the wind power gear box. The experimental results show that the method based on the combination of DEMD, local time-frequency entropy and SVM can be used to recognize and classify rolling bearing fault signals accurately and effectively.
		2017 Vol. 38 (4): 449-452 [Abstract] ( 755 ) HTML (1 KB) PDF (735 KB) ( 531 )

	453	A Differential Evolution Algorithm Based on Opposite Learning in Load Distribution for Cold Rolling
		ZHAO Zhi-wei
		DOI: 10.3969/j.issn.1000-1158.2017.04.15
		A differential evolution algorithm based on opposite learning is presented. In the proposed algorithm, to increase the diversity of initial population, the opposite learning is employed. In addition, the mutation strategy assigned to each individual is adaptively selected according to the selected probability, and the control parameters are generated by evolution-based monotone decreasing function and Logistic mapping. A large amount of simulation experiments have been made. Experimental results show that the proposed algorithm is better than other differential evolution algorithms. At last, the proposed algorithm is applied in load distribution for tandem cold rolling.
		2017 Vol. 38 (4): 453-458 [Abstract] ( 654 ) HTML (1 KB) PDF (425 KB) ( 524 )

	459	Effect Mechanism of Load Variation on Torsional Vibration for Single-phase Induction Motor
		ZHAO Hao,FENG Hao
		DOI: 10.3969/j.issn.1000-1158.2017.04.16
		For the influence of load variation on its torsional vibration, the application range of single-phase induction motor is limited. In order to analyze the effect mechanism of load variation on torsional vibration, the mathematical models of single-phase induction motor are established firstly, including the simplified equivalent circuit and corresponding phasor diagram, meanwhile the ellipse degree of rotating magnetic field is defined. Then the load is changed under the motor rated voltage, the torsional vibration of motor is tested and the results show that the existence of minimum, and the parameters of motor winding are changed correspondingly. The experimental results are analyzed by using phasor diagram finally, and the effect mechanism of load variation on torsional vibration for motor is revealed.
		2017 Vol. 38 (4): 459-463 [Abstract] ( 934 ) HTML (1 KB) PDF (571 KB) ( 564 )

	464	Study on the Influence Factors on Pressure Accuracy of Locomotive Wheel-set Press-fit
		XIAO Jun,DU Zhao-yong,YANG Zheng,HUANG Hai-tao
		DOI: 10.3969/j.issn.1000-1158.2017.04.17
		Factors that affect the pressure accuracy of locomotive wheel-set press-fit are studied. The hydrodynamic effects of wheel-set press-fit process are derived according to Navier-Stokes equations. Dynamic simulation of the spatial velocity of hydraulic oil is carried out by using the MATLAB PDE tool and the dynamic effects of different factors on the accuracy of locomotive wheel-set press-fit is analysed by this simulation. The static factors that affect the accuracy of the wheel-set press-fit process are also proposed according to the Lame formula and the traditional friction formula. The validity and accuracy of the method are verified through the experiment. The result shows that it can improve the accuracy of press-fit force by using proper parameter of wheel-set press-fit and quadratic curve to fit the relationship between the pressure and pressing force.
		2017 Vol. 38 (4): 464-468 [Abstract] ( 595 ) HTML (1 KB) PDF (703 KB) ( 515 )

	469	An Exciting-measuring Mode for Electrical Capacitance Tomography System
		ZHANG Li-feng,LIU Jing,TIAN Pei
		DOI: 10.3969/j.issn.1000-1158.2017.04.18
		In order to reduce the nonlinear and ill-posed inverse problem of electrical capacitance tomography (ECT), one kind of exciting-measuring mode is presented for ECT sensor consisting of 24 segments linked in 8 groups, treated as single, extremely broad electrodes forming 8-electrode sensor. The values and the dynamic range of measured capacitance data, the uniformity of sensitivity distribution and the reconstructed images of different flow regimes were compared with conventional exciting-measuring mode 12-electrode sensor. Two kinds of sensors were simulated by utilizing COMSOL and Matlab software. The simulation results showed that for the presented exciting-measuring mode, the number of independent measurements close to that of 12-electrode sensor, which will not cause the decrease of real-time reconstruction speed. However, the measured capacitance valves are larger and its dynamic range is smaller, which can reduce the difficulty of measurement circuit. Meanwhile, the sensitivity distribution is more uniform and the quality of reconstructed images for the objects in the central locations is improved obviously.
		2017 Vol. 38 (4): 469-472 [Abstract] ( 782 ) HTML (1 KB) PDF (394 KB) ( 464 )

	473	Research on On-line Water-meter Verification System Based on Computer Vision Technology
		CHEN Shuo,LIU Feng,TANG Xu-sheng,LUO Teng-bin
		DOI: 10.3969/j.issn.1000-1158.2017.04.19
		An on-line water-meter verification system based on computer vision technology is introduced. The template matching technology is used to locate the plum needle, and the teeth values of stand water-meter and the under-verified water-meters are counted while verifying. When the stand water-meter count to the set value, the system can automatically stop the counting and calculate the error of each under-verified water-meter and judge that the under-verified water-meter is qualified or not by the error. Field experimental results show that the system has a higher accuracy and works well on wet-dial water meter than that using laser reflection measurement method.
		2017 Vol. 38 (4): 473-476 [Abstract] ( 847 ) HTML (1 KB) PDF (611 KB) ( 657 )

	477	Research on Identification of Flow Rate and Temperature in the High Temperature Pipeline
		WANG Ye,YANG Li
		DOI: 10.3969/j.issn.1000-1158.2017.04.20
		The steady state heat conduction model of high temperature pipeline is established and calculated by the finite volume method. The relationship between the surface temperature distribution of the pipe and the flow rate and temperature is studied based on Levenberg-Marquardt algorithm. The effect of random measurement error on the results is studied by numerical simulation. The effectiveness of the proposed algorithm is proved and the method to reduce effect of the random error on identification results is discussed.
		2017 Vol. 38 (4): 477-480 [Abstract] ( 680 ) HTML (1 KB) PDF (521 KB) ( 721 )

	481	Design of sensors for measuring water in curved surface radome honeycomb based on the dielectric constant modulation
		YAN Gang,YAO En-tao,JIA Shang-yuan,JIANG Ning
		DOI: 10.3969/j.issn.1000-1158.2017.04.21
		The sensors for measuring water incurved surface radome honeycomb based on the dielectric constant modulation is developed. The dielectric constant indicates the relative capacity of the dielectric to store the electrostatic energy in the electric field. The dielectric constant of water is much larger than the dielectric constant of air and materials of radome, so it can be used to detect the cellular water of radome by the method of the dielectric constant modulation. In order to ensure the test sensitivity, the sensor plates must be closely attached to the measured structure. The shape of radome determines that the plate should be a flexible structure, which can fit the shape of curved surface, the sensor probe is composed of multi plates with a copper bar welding method, and the structure is optimized by using ANSYS software. Through testing the water of honeycomb structure, the experimental results show that the sensor can realize the water detection of honeycomb structure, and has high test sensitivity and repeatability.
		2017 Vol. 38 (4): 481-485 [Abstract] ( 509 ) HTML (1 KB) PDF (1378 KB) ( 438 )

	486	The Status of AC Quantum Voltage Standards
		ZHOU Kun-li,QU Ji-feng,ZHANG Zhong-hua,ZHAO Wei
		DOI: 10.3969/j.issn.1000-1158.2017.04.22
		Compared to the conventional voltage standards, Josephson voltage standards are more reproducible, stable and accurate. The principles, problems and applications of programmable Josephson voltage standards and pulse-driven AC Josephson voltage standards are reviewed. Moreover, their differences in metrological performance are compared and their developments in China are also presented.
		2017 Vol. 38 (4): 486-491 [Abstract] ( 729 ) HTML (1 KB) PDF (614 KB) ( 1067 )

	492	The Improvement and Experiment Analysis for a Four-Parameter Sine Wave Curve-fit Method
		LIANG Zhi-guo
		DOI: 10.3969/j.issn.1000-1158.2017.04.23
		To introduced a four-parameter sine wave curve-fit method, it based on the frequency estimation method, and then, combining with three-parameter sine wave curve-fit method, to realize the four-parameter sine wave curve-fit course, obtain the four parameters. The method is simple and easy to realize, it needn't pre-estimation of parameters and iteration, it has absolute convergent and high speed calculation course. But in case of lower A/D bites, the arithmetic method is unsteady, it always derives rough results, or wrong results. To these problems, this paper presents some experiments studies, the improvement arithmetic method is introduced, and the limitation of the method is taken out. It can be the base of the sine wave curve-fitting method in application. The correctness and rightness have proved by experiments results. The improved four-parameter sinusoidal curve-fitting method can be used in practice.
		2017 Vol. 38 (4): 492-498 [Abstract] ( 728 ) HTML (1 KB) PDF (1575 KB) ( 414 )

	499	The Denoise of the Atomic Clock Frequency Differences
		ZHU Jiang-miao,SUN Pan-pan,GAO Yan,QIN Hui-jun
		DOI: 10.3969/j.issn.1000-1158.2017.04.24
		To reduce the noise in the clock frequency, since the hydrogen atomic clock frequency differences are non-linear and non-stationary with time, the denoise algorithm based on ensemble empirical mode decomposition is put forward. Firstly, the clock frequency differences are added a certain intensity noise; then decompose the differences with the EMD algorithm, repeat this step many times; finally, calculate the mean of the same components to get the denoise clock frequency differences. Compared with the wavelet algorithm in the time domain and frequency domain, the result shows that, the algorithm put forward in this paper is better than the wavelet algorithm in the denoise of the clock frequency differences, the data variance is 0.7263% which is 2.707% in the wavelet algorithm, the data become more stable.
		2017 Vol. 38 (4): 499-503 [Abstract] ( 604 ) HTML (1 KB) PDF (2462 KB) ( 512 )

	504	Research on Method and Device of Non-disperse Atomic Fluorescence Exciting Source Impurity Detection
		JIA Ya-qing,WU Hong,SHEN Zheng-sheng
		DOI: 10.3969/j.issn.1000-1158.2017.04.25
		A detect method of impurity in non-dispersive atomic fluorescence exciting source is studied, and a kind of detection device is developed. A set of application software of the device is developed. The detection wavelength range of the device is 190～350nm, the maximum allowable error is ±0.3nm. It achieved fast detection function of the excitation light source impurity. Detection device and software are verified by the experiments.
		2017 Vol. 38 (4): 504-506 [Abstract] ( 615 ) HTML (1 KB) PDF (390 KB) ( 428 )

	507	Development of Component Analysis Reference Material for Acesulfame Potassium,Sorbic Acid and Sunset Yellow in Apple Vinegar Beverage
		JI Jie,LI Xiu-qin,MAO Ting
		DOI: 10.3969/j.issn.1000-1158.2017.04.26
		Acesulfame potassium, sorbic acid and sunset yellow in apple vinegar beverage is prepared and certified as component analysis reference material. High performance liquid chromatography-diode array detector(HPLC-DAD) method is optimized and established for target material measure and analysis. One-way analysis of variance of homogeneity test result shows that the reference material is homogeneous. Linear regression trend analysis of stability test result shows that the reference material is stable at least in 7 months. Values certified is cooperatively defined by 9 laboratories.The certified values and expanded uncertainty (k=2) are as follows: acesulfame potassium (141±8)mg/kg, sorbic acid (259±12)mg/kg, sunset yellow (8.45±0.33)mg/kg.
		2017 Vol. 38 (4): 507-512 [Abstract] ( 557 ) HTML (1 KB) PDF (520 KB) ( 472 )

	513	Flow Pulsation Study of HPLC Pumps
		YANG San-dong,PAN Qi,WANG Feng-yun,HAO Qing-li,TANG Tao,LI Tong
		DOI: 10.3969/j.issn.1000-1158.2017.04.27
		An innovative system was designed and constructed to measure flow pulsations of reciprocating pumps used in high performance liquid chromatography (HPLC). The flow pulsations of a serial pump and a parallel pump were studied under different conditions. The flow pulsation trends along with the changes of flow rates and backpressures of these two kinds of pumps were acquired. It was confirmed that the flow pulsation cycle was closed to the cam motion cycle. A pulsation damper was applied to reduce the flow pulsations to about 10% under 6.5MPa. This system and method were helpful to design and improve HPLC pumps.
		2017 Vol. 38 (4): 513-516 [Abstract] ( 794 ) HTML (1 KB) PDF (658 KB) ( 786 )

	517	Comparison of Uncertainty Evaluation between GUM S1 and Bayesian Analysis
		HU Hong-bo,SUN Qiao,DU Lei
		DOI: 10.3969/j.issn.1000-1158.2017.04.28
		Uncertainty evaluation method using GUM S1 and Bayesian analysis is proposed respectively. It is shown analytically that the GUM S1 solution is a special Bayesian analysis with certain parametrization and prior knowledge. When the model relation is linear and improper prior, GUM S1 and the Bayesian analysis yield the same results different results will emerge in general for non-linear model. The difference between the approaches is because of different parametrizations and different priors, which are illustrated by two examples. It is concluded that for a linear model both analyses can be applied, but for non-linear model, the GUM S1 approach may be preferred. When some prior knowledge about the measurement is available in practice work, it is proper to use the Bayesian analysis.
		2017 Vol. 38 (4): 517-520 [Abstract] ( 650 ) HTML (1 KB) PDF (559 KB) ( 465 )

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