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2018 Vol. 39, No. 4
Published: 2018-07-22
 
449 Robot Geometric Parameters Calibration Based on Axis Measurement and Iterative Compensation
WEN Xiu-lan,CUI Jun-yu,RUI Ping,ZHANG Teng-fei,KANG Chuan-shuai
DOI: 10.3969/j.issn.1000-1158.2018.04.01
In order to improve the absolute positioning accuracy of series industrial robots, the method of robot geometric parameters calibration based on axis measurement and iterative compensation is proposed. Firstly, robotic single axis motion trajectory is measured by the laser tracker and each axis position is computed by spatial projection method. Then, the actual parameters are extracted by the geometric meaning of the robot model parameters. The iterative compensation method based on distance errors is used to verify the results of the parameter calibration. Aifute ER10L-C10 industrial robot was used for calibration experiments and the experimental results shown that the maximum, average and standard deviation values of the absolute positioning errors are decreased from 4.215,1.932 and 1.437 mm to 2.979, 1.015 and 1.031 mm after calibration. It is proved that the method can calibrate the geometric parameters of the robot actual model quickly and easily and improve the absolute positioning accuracy of the robot.
2018 Vol. 39 (4): 449-454 [Abstract] ( 527 ) HTML (1 KB)  PDF (1257 KB)  ( 744 )
455 Development of Outdoor Baseline Environment Parameters Measurement System Based on Sensor Array
CHEN Yang,LI Jian-shuang,MIAO Dong-jing,XU Zhi-ling,LI Lian-fu,DENG Xiang-rui
DOI: 10.3969/j.issn.1000-1158.2018.04.02
In order to ensure the accuracy of distance measurement, a set of environmental parameters automatic measurement system is developed, by deploying dense sensor array along the outdoor baseline, including temperature sensors, air pressure sensors and humidity sensors, measuring the air temperature, air pressure and humidity and other environmental parameters on the optical path, performing air refractive index correction. Using μ-base distance meter to conduct distance measurement experiments under different climatic conditions, the measuring distance is 144 m. Experimental results show that using the system to measure environmental parameters, performing air refractive index correction, distance measuring uncertainty introduced by air refractive index correction error is better than 3.0×10-7(k=2).
2018 Vol. 39 (4): 455-460 [Abstract] ( 411 ) HTML (1 KB)  PDF (1073 KB)  ( 254 )
461 A Calculation Method of Products’ Qualified Probability of Bilateral Tolerance Limit
HUANG Fu-gui,LIU Zhi-sen,ZHAO Bao-sheng
DOI: 10.3969/j.issn.1000-1158.2018.04.03
A calculation model of products’ qualified probability is established to quantitatively analyze products qualification, considering the influence of uncertainty of parameter measurement and based on the assumption of normal distribution. The design requirement of products is bilateral tolerance limit. The model provides a theoretical basis for the quantitative calculation of batch products’ and single product’ qualified probability, and gives a calculation example of measurement and analysis. The results show that the quantitative calculation results of products’ qualified probability has an important guiding significance for the analysis of product quality problems and improving the quality of products. The given method also has referenced value for the calculation of product qualified probability, which design requirement of products is unilateral tolerance limit.
2018 Vol. 39 (4): 461-464 [Abstract] ( 428 ) HTML (1 KB)  PDF (588 KB)  ( 480 )
465 Dynamic and static calibration of nanosensors based on macro/micro motion control
ZHANG Hai-bo,KUANG Ye,TANG Yang-chao
DOI: 10.3969/j.issn.1000-1158.2018.04.04
To meet the requirements of calibration precision, calibration range and dynamic frequency response at the To meet the requirements of calibration precision, calibration range and dynamic frequency response at the same time, a macro/micro motion control method is used to drive the calibration device for fast, precise and wide-range positioning. the kinematics modeling of the micro-motion platform with static hinged/piezoelectric ceramic combination and the macro-motion platform with static pressure floatation/linear motor combination was carried out. And the transfer function of the platform is obtained. Two macro/micro control strategies, macro-follow-micro and micro-follow-macro, have been designed, simulated and compared. The experimental platform is built and the performance of the calibration device is tested. Experiment results show that the macro-follow-micro strategies has a higher dynamic response performance. Calibration device has the ability of 5 nm resolution in the whole stroke of 20 mm, and the dynamic frequency response up to 100 Hz in 0.05 mm amplitude in the sinusoidal frequency response, which can prove that the calibration device has dynamic and static calibration capability.
2018 Vol. 39 (4): 465-470 [Abstract] ( 402 ) HTML (1 KB)  PDF (2018 KB)  ( 265 )
471 Study on Nondestructive Testing for Bonding Defects in Aerospace Composite Based on Terahertz Image
PAN Zhao,WEN Yin-tang,ZHENG Xiao-kang,CUI Yao-yao
DOI: 10.3969/j.issn.1000-1158.2018.04.05
Thermal insulation aerospace composite and metal substrates’ bonding defects are tested by the reflection type frequency modulated continuous terahertz wave testing system which the frequency range is 0.23-0.32THz. Thermal insulation composite and metal substrates are bonded by epoxy resin adhesive as the experimental sample. Bonding defects of the adhesive interface can be detected visualized by image neighbor focal plane. Otsu’s threshold algorithm and FCM clustering algorithm is applied to get the segment of defect binary images combined with median filtering, then have the defect area by calculating the number of pixels. Compared with the samples which have known defect area, the FCM clustering algorithm is finally used because of the better segmentation effect and the error is about ±5%.
2018 Vol. 39 (4): 471-475 [Abstract] ( 510 ) HTML (1 KB)  PDF (1027 KB)  ( 554 )
476 Rapid Vision Measurement of LED Die Array Based on Cross Correlation in Frequency Domain
LI He-xi,HAN Xin-le,YANG Tie-niu
DOI: 10.3969/j.issn.1000-1158.2018.04.06
A rapid template matching method based on cross correlation in frequency domain(CCFD) is presented for real-time visual measurement of light-emitting diode (LED) die. First, the gray value of LED die array image is normalized by a recursion-sum algorithm in spacial domain, and then using fast Fourier transform the CCFD is carried out between LED die array image and die template to rapidly locate all pixel coordinates of LED dies. The higher measurement efficiency can be obtained because of omitting image normalization for clear binary images of LED die array. Experimental results of complex LED die images show that the measurement efficiency is far higher than conventional normalized cross-correlation(NCC) algorithm, and is only half of consumed time to compare with the sequential similarity detection algorithm(SSDA). The proposed CCFD algorithm can be used for rapid LED die measurement in LED sorting or die-bonding system.
2018 Vol. 39 (4): 476-480 [Abstract] ( 393 ) HTML (1 KB)  PDF (1251 KB)  ( 250 )
481 Structure Design of Schlieren Apparatus Light
CHEN Hai-bin,TANG Ying,ZHANG Xiong-xing,WANG Wei
DOI: 10.3969/j.issn.1000-1158.2018.04.07
Based on the basic principle of Schlieren apparatus, the causes of poor Schlieren instrument image quality are analyzed, and the light source parts with focusing lens solutions is proposed. In-depth analysis and calculating the size of the adding together after focusing lens flare, at the same time, for convenient adjusting, a coaxial clamp design frame is designed. Through the experiment of the entire system, after the focusing lens and two kinds of temperature at 60℃ and 90℃ in heating platform, the imaging quality is obvious improved, air turbulence is observed more apparently.
2018 Vol. 39 (4): 481-484 [Abstract] ( 750 ) HTML (1 KB)  PDF (631 KB)  ( 791 )
485 A Calibration Method of Binocular Vision System
LI Di-fei,CHEN-He,FENG Zhi-gang,ZHAO Ke-jia,LIU Zheng,GAO Hong-ying
DOI: 10.3969/j.issn.1000-1158.2018.04.08
The camera calibration method of binocular vision system which can be used in trajectory tracking is based on image analysis and three-dimensional spatial position modeling algorithm of artificial neural network. The calibration plane with uniformly distributed target points was placed in multiple positions within the camera field. The images of calibration plane are captured by the binocular vision system. Afer image processing, the coordinates of the target points are determined. The coordinates of the points are used as input data set of the artificial neural network. Througth optimizing parameters of the artificial neural network, the mapping relationship between the two-dimensional coordinates of the target point and the three-dimensional spatial coordinates is determined. With this versatile method, distortion factors of the binocular vision camera system can be eliminated and three-dimensional position information without complicated proceduring of camera calibration operation. The experiment result demonstrates that the calibration method has good feasibility and robustness.
2018 Vol. 39 (4): 485-489 [Abstract] ( 440 ) HTML (1 KB)  PDF (1734 KB)  ( 655 )
490 Analysis of spectral mismatch error influences on measurement of reference solar cell
CAI Chuan,ZHANG Jun-chao,XIONG Li-min,ZHOU Tao-geng,HE Ying-wei,MENG Hai-feng,ZHANG Ke-jia,ZHANG Bi-feng
DOI: 10.3969/j.issn.1000-1158.2018.04.09
Spectral mismatch error influences on measurement of reference solar cell by means of solar simulator and calibrated reference cell is discussed. Reference solar cell short-circuit current can be used to determine the total irradiance intensity of the solar simulator. Experimental results, two cells, one test and one ref, with two different spectra solar simulators, were presented. Spectral mismatch error can be calculated with the relative spectral response of the test and reference cells, and the relative spectral irradiance of the simulator and reference solar. The calculation method and experimental data presented could be positive reference to photovoltaic labs to obtain good calibration and test results of solar cells.
2018 Vol. 39 (4): 490-492 [Abstract] ( 421 ) HTML (1 KB)  PDF (604 KB)  ( 332 )
493 HDR Infrared Image Detail Enhancement Method Based on the FPGA
LIU Bin,ZHAO Jian-zhang,KONG Xiang-xin,WU Zhao-bin,MENG Zong,HU Chun-hai
DOI: 10.3969/j.issn.1000-1158.2018.04.10
In the technical framework of unsharp masking method, an image detail enhancement method which based on the guided filter and γ transformation was proposed. A new type of filter type architecture is designed, and use VHDL language in hardware platform of CYCLONE Ⅲ for the project implementation. The logic and memory resource of the core processor accounted for 15% and 40% respectively. With a 100MHz master clock, processing latency less than 300μs and using the low-end processors can meet the engineering requirements. Experiments successfully approved the proposed algorithm has good results in detail enhancement.
2018 Vol. 39 (4): 493-497 [Abstract] ( 602 ) HTML (1 KB)  PDF (958 KB)  ( 453 )
498 The Preprocessing Method of the Blade Tip-timing Measurement without a Once-per-revolution Sensor and Error Analysis
ZHANG Ji-long,DUAN Fa-jie,NIU Guang-yue
DOI: 10.3969/j.issn.1000-1158.2018.04.11
A method for preprocessing tip-timing signals that does not require a once-per-revolution (OPR) sensor is proposed.The method measures the difference in the blades vibration displacement when it arrives at different tip-timing sensors to identify the blades vibration parameters and the rotational speed of the rotor.Error analysis indicates that the method can reduce the rotational speed measurement error and its impact on the vibration displacement measurement.The measurement error of the difference in vibration displacement is analyzed and compared with the method that requires an OPR sensor.Experiment results show that the method is feasible for BTT signal preprocessing without an OPR sensor and is very accurate.
2018 Vol. 39 (4): 498-503 [Abstract] ( 420 ) HTML (1 KB)  PDF (1475 KB)  ( 261 )
504 Volume Metrology Method for Micro Liquid Based on Laser and Machine Vision
ZHANG Jing-yue,SUN Bin,XIE Xuan-da,ZHAO Yu-xiao,TONG Lin,ZHANG Long,ZHOU Lu
DOI: 10.3969/j.issn.1000-1158.2018.04.12
For the liquid volume measurement of volumetric glass gauge, a liquid level measurement method for micro liquid volume based on laser and machine vision technology was proposed. A volume table for correspondence relationship of liquid level and capacity in the standard glass gauge was established. The corresponding value of liquid volume can be obtained by measuring the liquid level. Measuring the liquid level of the standard glass gauge is the main point in the method. Liquid level measurement combined with computer and digital image processing technology, and used high-resolution camera and image processing software to extract feature element. High-precision volume measurement was realized, a comparative test with the static measure method was also designed, and validated the method. For the 100mL glass container, the measuring accuracy is better than 0.2%, the expanded uncertainty of the fitting algorithm is 0.137% (k=2), and the repeatability of measurement is 0.08%.
2018 Vol. 39 (4): 504-509 [Abstract] ( 442 ) HTML (1 KB)  PDF (514 KB)  ( 497 )
510 Compensation Method for Creep Error of Load Cell Based on Neural Networks
WANG You-gui,WU Shuang-shuang,CHEN Hong-jiang
DOI: 10.3969/j.issn.1000-1158.2018.04.13
The resistance strain load cell has heavy creep error, which will lead to the low accuracy of weighing results. To reducing this error, a model compensation on the load cell’s creep error based on neural networks(NNs) is proposed, and the training algorithms of the model is given. The experimental results of the load cell which capacity is 50 kg and its accuracy class is C3 show that the creep errors of the load cell with this proposed model are less than those without compensation, and the maximal change of its creep errors is 0.0108 kg, it is less than that of the maximal permissible error defined by Chinese National Standard, GB/T 7551—2008 “Load cell”.
2018 Vol. 39 (4): 510-514 [Abstract] ( 468 ) HTML (1 KB)  PDF (1583 KB)  ( 699 )
515 A New Feature Extraction Method of Weak Fault Signal Based on VMD and Re-scaling Multi-stable Stochastic Resonance
SHI Pei-ming,SU Xiao,YUAN Dan-zhen,SU Guan-hua,MA Xiao-jie
DOI: 10.3969/j.issn.1000-1158.2018.04.14
To realize the feature extraction of rotating machinery in the strong noise environment, a feature extraction method of weak fault signal based on variational mode decomposition and re-scaling multi-stable stochastic resonance is proposed. The first application of parameter optimization of variational mode decomposition (VMD) algorithm for fault signal is decomposed into several intrinsic mode functions (IMFs), and then through the kurtosis criterion and find the maximum kurtosis of IMF component, finally the characteristic frequency of the IMF component through the re-scaling multi-stable stochastic resonance system will be enhanced, which is easily and clearly detected. The simulation analysis and experiments reveal that, in the strong background noise, the combination of optimized VMD algorithm and the method of re-scaling multi-stable stochastic resonance system, can effectively extract weak feature frequency information and realize the accurate judgment of the rotating machinery fault state.
2018 Vol. 39 (4): 515-520 [Abstract] ( 513 ) HTML (1 KB)  PDF (1172 KB)  ( 664 )
521 A Inductive Instantaneous Rotation Angular Rate Sensor Based on Hall Effect
ZHAO Hao
DOI: 10.3969/j.issn.1000-1158.2018.04.15
A inductive instantaneous rotation angular rate sensor based on Hall effect is presented, the sensor is mainly composed three parts, including stator core and winding, Hall element and permanent magnet rotor, the flux distribution of permanent magnet rotor in the air gap is sine regularity. The permanent magnet rotor is connected to the test device coaxially when at work, and the magnetic field of permanent magnet rotor is coupling with the stator winding, then the induction electromotive force in stator windings is generated, which is corresponding to the instantaneous rotation angular velocity. For the stator winding is directly connected with the control terminals of the Hall element, the current in Hall element is produced, and the DC Hall potential is generated under the effect of magnetic field of permanent magnet rotor, which is proportional to the instantaneous rotation angular velocity. The output characteristic of sensor is deduced, and the determination testing is carried out, the results show that the sensitivity coefficient of sensor is about 203 mV/(rad·s-1) , and the linear error is about 0.5%.
2018 Vol. 39 (4): 521-524 [Abstract] ( 423 ) HTML (1 KB)  PDF (854 KB)  ( 290 )
525 Analysis and Development of Electromagnetic Flowmeter Pulse Excitation System Based on PWM Control
XU Wei,XU Ke-jun,LIANG Li-ping,YANG Shuang-long
DOI: 10.3969/j.issn.1000-1158.2018.04.16
In order to improve the excitation frequency and reduce heat generation, making electromagnetic flowmeter (EMF) be able to measure slurry flow and fill better, and also work in a stable way, the pulse excitation scheme based on PWM control method was studied, its operational principle was analyzed, its various parameters were calculated, the actual system was developed, and tests and experiments were conducted. Results showed that the system can realize the higher frequency excitation with stable excitation current, which greatly reduced power consumption of excitation circuit. It can also prevented the differential interference from influencing the flow signal and its verification accuracy was better than 0.5% on water flow calibration.
2018 Vol. 39 (4): 525-530 [Abstract] ( 428 ) HTML (1 KB)  PDF (373 KB)  ( 468 )
531 Method of Setting Empty/Full Field for Coplanar Capacitance Array Imaging Sensor
ZHANG Yu-yan,SUN Dong-tao,ZHANG Zhen-da,WEN Yin-tang
DOI: 10.3969/j.issn.1000-1158.2018.04.17
Using a conventional single dielectric medium as empty or full field often leads to the low measurement accuracy when the planar array electrode capacitance imaging technology is applied to nondestructive testing of defects, because electrodes are arranged in the same plane. A method of setting the relative empty/full field using air and tested material as dielectric is proposed. The capacitance value of empty/full field is adjustable and non-unique by changing the spatial position and size of the two kinds of medium, respectively. The working principle of the planar array capacitance sensor is described and the sensitivity matrix is obtained by means of finite element simulation for measure field made up of heat insulating material and epoxy resin. Experimental study on capacitance imaging is conducted for empty and full field setting method. The results show that the imaging quality can be improved, the plane position information of defects in the object is given, and the validity of the method is verified.
2018 Vol. 39 (4): 531-535 [Abstract] ( 381 ) HTML (1 KB)  PDF (1349 KB)  ( 273 )
536 A Method of CT/ECT Image Fusion Based on Wavelet Transform
MA Ping,SI Zhi-ning
In the multi-phase flow parameter measurement based on industrial CT and ECT, CT reconstruction of the image resolution is higher, however its low projection angle, it can cause the reconstruction image edge distortion. For the ECT system, because of its sensitive field soft field feature, reconstructed image resolution is low, but the image edge fidelity is high. Based on the complementary characteristics of the two methods, the CT/ECT image fusion method was studied. The improved logic filter algorithm was applied to the low frequency coefficient fusion rules of wavelet transform. The results showed that the method can improve the quality of reconstructed image after fusion.
2018 Vol. 39 (4): 536-540 [Abstract] ( 402 ) HTML (1 KB)  PDF (760 KB)  ( 710 )
541 The Test of the Surface Acoustic Wave Tag Based on the ADS Semi-physical Platform
CHEN Zhi-jun, CHEN Tao,XU Hai-lin,YAO Min,JIA Hao
DOI: 10.3969/j.issn.1000-1158.2018.04.19
To test the surface acoustic wave (SAW) tag, the ADS semi-physical platform is proposed. This method utilizes the vector network analyzer for the measurement of the S parameters of the SAW tag, and establishes its abstract model in the ADS software. With the virtual excitation signal in the ADS, the echo signal of the tag is obtained by the ADS transient simulation function. The digital quadrature demodulation is implemented by the MATLAB software to measure the time delays and phases of the reflectors on the tag objectively and accurately. The SAW tag is tested by the above mentioned semi-physical platform, and the measurement results show the effectiveness of the ADS semi-physical platform.
2018 Vol. 39 (4): 541-544 [Abstract] ( 412 ) HTML (1 KB)  PDF (1058 KB)  ( 364 )
545 Traceability Experiments on 10GΩ On-wafer High Resistance
LIU Yan,QIAO Yu-e,DING Chen,LIANG Fa-guo
DOI: 10.3969/j.issn.1000-1158.2018.04.20
A modified on-wafer high resistance measuring system, along with customized trace-back method, is developed to fulfill the traceability requirements. On-wafer high resistance is successfully traced back to a standard resistor with the system. The system is equipped with extra probes and leads in order to extend the ports of the resistor standard to the tips of the probes and on-wafer thru lines are used to short the corresponding probes. Thus a circuit taking a Lead-On-wafer-Lead form is build to connect on-wafer measurement with a resistor standard. A conservative method is given to evaluate the uncertainty of the proposed system. Experiments on traceability are taken, and the uncertainty of the system achieved 0.3%(k=2) at 10 GΩ.
2018 Vol. 39 (4): 545-548 [Abstract] ( 476 ) HTML (1 KB)  PDF (641 KB)  ( 244 )
549 Research on Air Gap Influence on Magnetic Shielding Effectiveness for Current Comparator
WANG Xue,ZHENG Tian-yu,XIANG Qiong,LI Dong,CHEN De-zhi,LIU Peng-yuan
DOI: 10.3969/j.issn.1000-1158.2018.04.21
Magnetic shield of the current comparator is an important structure to decrease the magnetic error and ensure high measurement accuracy and its ability is defined by the magnetic shielding effectiveness. Considering the air gap caused by wires through the magnetic shield, a finite element method (FEM) model is established to study the relationship between air gap length and magnetic shielding effectiveness.To this specified size of model, the FEM results show that when the air gap length is lower than 10 mm, the magnetic shielding effectiveness is almost unaffected, while when the air gap is larger than 10 mm, it decreases dramatically. Finally, an experimental device is built to verify the effect of air gap on the shielding effectiveness. The FEM results and experiment results both draw a conclusion that small air gap have little effect on magnetic shielding effectiveness, while when air gap reach a certain length it will have a significant deteriorate effect, so in application the air gap should be constrained to a proper length.
2018 Vol. 39 (4): 549-553 [Abstract] ( 429 ) HTML (1 KB)  PDF (1692 KB)  ( 252 )
554 Indoor Positioning Algorithm for WLAN Based on KFCM-LMC-LSSVM
WANG Yu-jie,WANG Yuan,ZHANG Yong
DOI: 10.3969/j.issn.1000-1158.2018.04.22
To solve the problems of large workload whe the fingerprint database is constructed and low positioning accuracy in WLAN indoor positioning system. An indoor positioning algorithm was presented, which integrates kernelized fuzzy C-means(KFCM), low rank matrix completion (LMC) and least squares support vector machine(LSSVM). Firstly, the KFCM is used to cluster the fingerprint points, the test points are sorted into one of the small areas. According to the LMC theory, the low rank fingerprint database into high density fingerprint database was translated. Finally the position of the test points is determined by the LSSVM algorithm. Experiments showed that the KFCM-LMC-LSSVM algorithm not only reduces the workload of building the fingerprint library, but also has higher positioning accuracy.
2018 Vol. 39 (4): 554-558 [Abstract] ( 482 ) HTML (1 KB)  PDF (996 KB)  ( 234 )
559 A Computing Method for Isotropy of E-field Probe Based on Plane Geometry
XIONG Yu-fei,ZHOU Feng,LIU Jian-zhe
DOI: 10.3969/j.issn.1000-1158.2018.04.23
A computing method based on plane geometry which is used to calculate the isotropy of E-field probe is purposed. And the generality and reasonability of the method have been proved through theoretical deduction and experiment validation. Based on the experimental results, it shows that the results difference between the new method and the one used in Standard IEEE-1309 is 0.01~0.08 dB. But through comparison of the new method to the one used in IEEE-1309, it shows that the method can not only evaluate the isotropy of E-field probe but also can have positive effects on the improvement of isotropy of E-field probe at the same time.
2018 Vol. 39 (4): 559-561 [Abstract] ( 399 ) HTML (1 KB)  PDF (363 KB)  ( 198 )
562 A Predictive Control Algorithm Based on Trapezoid Interval Soft Constraint and Multi-objective Optimization
LIU Bin,GU Xin-feng,SUN Chao,ZHANG Chun-ran,LIU Hao-ran
DOI: 10.3969/j.issn.1000-1158.2018.04.24
Based on triangle interval soft constraint, a trapezoid interval soft constraint and multi-objective optimization algorithm was presented.The algorithm set up a trapezoidal interval outside the tolerance interval, and the control process is divided into two parts to reduce the effects of the initial transient deviation on the system. In order to alleviate the control target of mutual coupling problems in the industrial process, two objective functions were constructed, and the coordination control of MIMO system was achieved by the method of ε -constraint which is improved with iterative algorithm, and then solving the objective function, to reduce the errors of the objective function and realize the coordination control for MIMO systems. Finally, the simulation has been done with the heavy oil fractionator model of Shell company, predictive control algorithm based on triangle interval soft constrain compared with this algorithm, the rusult show that the proposed algorithm has better optimization.
2018 Vol. 39 (4): 562-567 [Abstract] ( 440 ) HTML (1 KB)  PDF (1029 KB)  ( 363 )
568 Research on System of New Frequency Measurement Based on Multi-channel Dual Mixer Time Difference Measurement Instrument
ZHANG Yue,WANG Yu-zhuo,ZHANG Ai-min,Dong Kun,WANG Wei-bo
DOI: 10.3969/j.issn.1000-1158.2018.04.25
Research on the improvement of frequency standard measurement capability in recent years in NIM, the principle of dual mixer time difference measurement method, the basic structure and measurement results of new frequency measurement system based on comparing with old system of standard frequency are introduced, which is newly developed by NIM. The new frequency measurement system adopts dual mixer time difference measurement method and the uncertainty of the system is better than 3×10-13 (sample time is 1 second) and realizes the metrology of long-term and short-term stability of frequency standard, it proves that the system is high efficiency integrated test system.
2018 Vol. 39 (4): 568-571 [Abstract] ( 445 ) HTML (1 KB)  PDF (1495 KB)  ( 551 )
572 Water Quality Monitoring Based on Fish Movement Characteristics and XGBoost
CHENG Shu-hong,ZHANG Shi-jun,LI Lei-hua,ZHANG Dian-fan
DOI: 10.3969/j.issn.1000-1158.2018.04.26
Realization of water quality monitoring by combining fish movement behavior with XGBoost classifier.According to the influence of water quality on the movement of fish, some characteristic parameters were introduced, such as center distance index, dispersion and distribution area, which were extracted from the movement behavior of fish. Secondly, five characteristic parameters of swimming distance, velocity, acceleration, curvature and neighborhood of fish in normal and abnormal water quality were extracted, and water quality anomaly evaluation factor database was established. Finally, different evaluation factors were input to XGBoost classifier for classification and recognition. The experimental results showed that the three characteristic parameters of the center distance index, dispersion and distribution area can reflect the water quality condition high efficiency and accurately.
2018 Vol. 39 (4): 572-577 [Abstract] ( 566 ) HTML (1 KB)  PDF (1238 KB)  ( 469 )
578 A Detection Method for Oxygen, Nitrogen and Hydrogen Content of Superalloy’s New Surface during High-speed Finish Milling
SUN Tao,LIANG Jin,LI Deng-wan,WEI Bin,ZHONG Ling
DOI: 10.3969/j.issn.1000-1158.2018.04.27
A detection method for oxygen, nitrogen and hydrogen content of superalloys new surface during high-speed milling was proposed through the detection of oxygen, nitrogen and hydrogen content of chips indirectly based on the infrared-thermal conductivity method. And a high-speed fine milling experiment program was projected by uniform design method. The quadratic regression model of superalloy was established using best regression subset method and the regression effect was good.
2018 Vol. 39 (4): 578-582 [Abstract] ( 454 ) HTML (1 KB)  PDF (391 KB)  ( 212 )
583 Uncertainty Evaluation for CFR Octane Number Testing System of Gasoline
WANG Jia-xing,ZHANG Hui-cheng,GAO Bo,LING Feng-xiang
DOI: 10.3969/j.issn.1000-1158.2018.04.28
Octane number testing system is set up in order to get the octane number of gasoline. The components of uncertainty influencing on the measurement of octane number, including automatic manufacture standard sample machine, repeated test of octane number and CFR engine, are analyzed in the system. The uncertainty are calculated. Synthesizing the uncertainty results of all the components show that octane number testing system for the expanded uncertainty of research octane numeber is 0.7 at 95% confidence level, which meet the demand for measurement uncertainty of gasoline fuel.
2018 Vol. 39 (4): 583-587 [Abstract] ( 476 ) HTML (1 KB)  PDF (843 KB)  ( 569 )
588 Study on Measurement Method of Serratia Marcescens
SUI Zhi-wei,LIU Xiao-xia,WANG Jing,FU Bo-qiang,XUE Lei,LIU Si-zhang,HAO Lin
DOI: 10.3969/j.issn.1000-1158.2018.04.29
Serratia marcescens was traditionally used as microbiology indicator of biological protection evaluation. Nutrient agar tablet coating method for Serratia marcescens were validated, collaborative experimental verified, and uncertainty analyzed. The results showed that nutrient agar tablet coating method had a good repeatability and reproducibility, the interassay relative standard deviations was 8.93%, and external laboratory relative standard deviations was 14.95%. The statistic test showed that the relative expanded uncertainty of nutrient agar tablet coating method was 12.60% (k=2), which could be used for quantitative measurement of Serratia marcescens.
2018 Vol. 39 (4): 588-592 [Abstract] ( 522 ) HTML (1 KB)  PDF (355 KB)  ( 430 )
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