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2011 Vol. 32, No. 1
Published: 2011-01-22
 
1 Analysis Engineering Surface with Fractional Spline Filter
ZHANG Hao,YUAN Yi-bao,PIAO Wei-ying,ZHANG Feng
DOI: 10.3969/j.issn.1000-1158.2011.01.01
Fractional spline theory is proposed as a new profile filter for mean line extraction. First, the fractional spline filter is derived by combining fractional spline function with variational principle. The amplitude transmission characteristics of this filter show its adjustability of cut-off characteristics, which can approach ideal low pass filter when the order of spline increases enough, and approximate to Gaussian filter when order is defined 1.51. A fast FFT algorithm is given to perform fractional spline filter. Provided with the limited number of multiplication operation during frequency domain, the computation is testified efficient. Finally, the reasons of end distortion during this algorithm are discussed, and this distortion called end effect is remedied. Experimental results indicate this filter algorithm preserves not only adjustable cut-off characteristics, but also fast computation speed. Based on this filter, once extraction for mean line of 11200 data points only costs 4 ms on general computer. In addition, the end effect existing in spline filter is alleviated by this algorithm availably.
2011 Vol. 32 (1): 1-6 [Abstract] ( 657 ) HTML (1 KB)  PDF (1361 KB)  ( 418 )
7 Research on the Corner Detection Algorithm Based on Image Size Transformation
PAN Hui,WANG Min,XU Jian-liang,XU Ai-jin,QI Xiao-li,XU Si-xiang
DOI: 10.3969/j.issn.1000-1158.2011.01.02
In order to study the efficiency of the corner detection method which is based on image size transformation, a new detection technique named corner detection of image size enlarging transformation is presented, which is based on image size reducing transformation theory. A detailed introduction and experiment verification about the two kinds of detection methods are given. The experiment results show the validity of the methods. On this basis, a comparison about the image corner detection results with these two methods and the original method (no image size transformation) is described. According to the results, the detection accuracy is approximately the same. Therefore, it’s not necessary to change the image size in practical corner detection.
2011 Vol. 32 (1): 7-11 [Abstract] ( 577 ) HTML (1 KB)  PDF (2212 KB)  ( 380 )
12 Research on Self-calibration Technology of the Indoor GPS Industry Measurement System
LV Jing-liang,ZHANG Chun-fu,TANG Wen-yan,HAO Xin-yu
DOI: 10.3969/j.issn.1000-1158.2011.01.03
The relative positions and spatial attitudes of transmitters in Indoor GPS industry measurement system should be calibrated before the measurement being carried on. A single cylindrical sensor will be adopted combining a scale bar to obtain the azimuths and elevations of the transmitters at different spatial points in order to carry on the self-calibration. The transforming model of coordinate parameters based azimuth and elevation angles are established and calculated through least square algorithm of non-linear optimization to accomplish the self-calibration. Experiment testing shows that this calibration method is convenient and feasible.
2011 Vol. 32 (1): 12-15 [Abstract] ( 505 ) HTML (1 KB)  PDF (575 KB)  ( 684 )
16 Measurement of Line-width and Line-width Roughness Based on Equivalent Area
LI Hong-bo1,2,ZHAO Xue-zeng2,ZHAO Wei-qian1
DOI: 10.3969/j.issn.1000-1158.2011.01.04
A method to measure line-width and line-width roughness (LWR) is presented based on the outline feature of the step scanned by AFM. Ideally, the step cross-section along the direction of the line-width is rectangle, whose area, S, is the product of height and line-width. Actually, the outline of the step cross-section is polygonal, whose area, S1, is equaled to S. The height of the profile scanned by AFM, H, is calculated by improving Tsai’s height algorithm. So, line-with, We, is calculated according to S1 and H. LWR is also calculated according to its definition as the 3σ value of line-width variation.
2011 Vol. 32 (1): 16-19 [Abstract] ( 497 ) HTML (1 KB)  PDF (628 KB)  ( 436 )
20 The Dynamic Measurement Method with Elimination of Noise Disturbance
WU Huai-gang
DOI: 10.3969/j.issn.1000-1158.2011.01.05
Due to measurement noise and frequency response of compensator, the dynamic compensator of the sensor has severely noise disturbance.The parameter estimate of the compensator and measurement precision is effected by the noise. A new dynamic measurement method for eliminating noise disturbance is described. To implement this method, the noise variance was estimated by the wavelet transform, and then a recursive least-squares method with bias-elimination was applied to estimate the unbiased parameters of the compensator. At the same time, polynomial prediction filter was used to eliminate the effect of high frequency noise on measurement precision. Experimental results show that the approach is effective.
2011 Vol. 32 (1): 20-24 [Abstract] ( 485 ) HTML (1 KB)  PDF (508 KB)  ( 401 )
25 Two-wire Vortex Flowmeter Based on Digital Spectral Analysisand Analog Band-pass Filter Group
XU Ke-jun,LIU San-shan,LIU Jia-xiang,LUO Qing-lin
DOI: 10.3969/j.issn.1000-1158.2011.01.06
Combining digital spectral analysis with analog band-pass filter group and adopting the micro-control unit MSP430F1611, a novel digital vortex flowmeter with the two-wire output is developed, which can the measuring range, ensure the measurement accuracy in fields, and operate in low-power. It solves the key technique problem in this kind of flowmeters. A programmable amplifier is constructed by an amplifier with low-power and digital potentiometers in order to adapt large change of amplitude of vortex sensor output. A band-pass filter group is selected by the computation result of small number FFT to cover the variation range of vortex frequency and perform optimal filter for the vortex signal. A power management module and current output circuit are designed to provide enough electrical current for meter operation with two-wire.
2011 Vol. 32 (1): 25-30 [Abstract] ( 523 ) HTML (1 KB)  PDF (401 KB)  ( 861 )
31 Study on the Measurement of Pulverized-coal Concentration using Electrical Capacitance Tomography
LIU jing,SUN Meng,LIU Shi
DOI: 10.3969/j.issn.1000-1158.2011.01.07
Based on electrical capacitance tomography, subtle mass flow measurement of pulverized coal pneumatically conveyed under normal temperature conditions is studied. To adequately make use of the capacitance sensors ensitivity field, a cyclone separator is set up in the experimental system, which could gather solid particles on wall areas, while the sensor pole is placed on straight section of the separator. The concentration is altered by changing the screw feeder speed and the suction amount on the top of the cyclone. The distribution of volume concentration in radial direction, the average volume concentration and the fluctuating characteristics are analyzed. The feasibility and reliability of the method are verified by experimental results.
2011 Vol. 32 (1): 31-35 [Abstract] ( 652 ) HTML (1 KB)  PDF (1068 KB)  ( 659 )
36 Studies on Three Driving Methods of Coriolis Mass Flowmeter
LI Miao, XU Ke-jun,ZHU Yong-qiang,HOU Qi-li,LI Ye
DOI: 10.3969/j.issn.1000-1158.2011.01.08
Aiming at the driving problem of Coriolis mass flowmeter, the driving methods of analog,semi-digital, and all-digital are compared and achieved . For Micromotion-CNG050 type Coriolis mass flow sensors, a secondary instrument is developed with DSP, to achieve the driving experiments. The problems in driving respectively is analyzed based on digital signal synthesis with digital devices. The experimental results show that the performance of them is improved gradually.
2011 Vol. 32 (1): 36-39 [Abstract] ( 678 ) HTML (1 KB)  PDF (388 KB)  ( 982 )
40 Study on Air Density Measurement for Measuring Weights
WANG Xiao-lei,WANG Jian,ZHONG Rui-lin,ZHANG Yue,CAI Chang-qing,YAO Hong,DING Jing-an
DOI: 10.3969/j.issn.1000-1158.2011.01.09
To determine air density for high accuracy measurement of the weights, the method using the recommended equation is studied. According to the CIPM-2007 equation, an equipment of air density measurement that for high accuracy measurement of the weights is developed. Measurement of temperature, humidity, pressure and CO2 are integrated on it to measure air density automatically. Comparing with the results using approximation formula for air density, the relative error of 0.022% is achieved when CO2 is 937.4×10-6. The experimental results prove that additional measurement of CO2 can improve accuracy of air density measurement.
2011 Vol. 32 (1): 40-43 [Abstract] ( 737 ) HTML (1 KB)  PDF (351 KB)  ( 898 )
44 A New Measuring Airdata Algorithm
WANG Li-xin, TAO Jian-wu
DOI: 10.3969/j.issn.1000-1158.2011.01.10
A new measuring airdata algorithm is put forward.A vector sensor is applied to the flush airdata sensing(FADS) system to measure the airdata, the mathematics model of particle velocity, sound velocity and airspeed is established, the mach number can be computed, then impact-static pressure can be solved by the mach number. The less computational load and the real-time measurement can be achieved. The simulation shows this method is effective.
2011 Vol. 32 (1): 44-48 [Abstract] ( 529 ) HTML (1 KB)  PDF (340 KB)  ( 643 )
49 Study on a New Method for Measuring the Moment of Inertia
ZHANG Yong,SUN Ning,REN Yong-chuan,LIANG Yong-hu
DOI: 10.3969/j.issn.1000-1158.2011.01.11
With the kinetic energy theorem of the rigid body rotating round fixed axis, the relation between the moment of inertia of a single axis air bearing table rotating around fixed axis and time is established.On this basis, a new method for measuring the moment of inertia based on energy attenuation of a single axis air bearing table is described.Through detailed theoretical deduction, the experimental formula for measuring the moment of inertia of the objects is obtained.And the experimental results of measurement are verified.The results show that the relative error between the experimental results and the theoretical results is within ± 0.5%.
2011 Vol. 32 (1): 49-52 [Abstract] ( 432 ) HTML (1 KB)  PDF (309 KB)  ( 834 )
53 A Fluid Level Measurement Method Based on Acoustical Resonance in a Special Frequency Range
XU Xiao-bin,ZHAO Chen-ping,XIA Bing-duo,WANG Zhi,WEN Cheng-lin
DOI: 10.3969/j.issn.1000-1158.2011.01.12
The range of original level measurement methods by acoustic resonance principle is limited by the fundamental resonance frequency (RF). It causes inability in long distance measurement. In order to overcome this limitation, a new liquid level measurement method is presented based on RFs in a special high frequency range. A set of RFs in this frequency range is detected in stead of the fundamental RF. Many measurements can be calculated by the equi-different relationships between adjacent RFs and the RF conversion formula of the level. The mean of these measurements is considered as a final value so as to reduce measuring uncertainty. In addition, the proposed detection algorithm can fast obtain RFs and improve the real-time performance. Experimental results show that new method has longer measurement range, insensitive to some foams or residues. Its measuring accuracy is up to 1‰ better than 3‰~5‰ accuracies of the original methods and the common ultrasonic gauges.
2011 Vol. 32 (1): 53-57 [Abstract] ( 506 ) HTML (1 KB)  PDF (532 KB)  ( 972 )
58 2D Defect Profile Reconstruction of High-speed Magnetic Flux Leakage Testing
WANG Chang-long,LEI Liang-jin,JI Feng-zhu
DOI: 10.3969/j.issn.1000-1158.2011.01.13
Considering the key techniques and difficulties of defect visualization in high-speed MFL testing, to preprocesses defect MFL signals through lifting wavelet package method, a theoretic analysis to the influence for MFL signals of the velocity of the sensor in high-speed MFL testing based on electromagnetic field essential theory is given. Present RBF neural network compensation measure which based on regularization theory, and gained the velocity invariance response of the defect MFL signals through net mapping. And RBF networks which optimized by ant colony algorithm for two-dimensional inversion of defect MFL signals is applied to implements Profile Reconstruction of 2D defect.
2011 Vol. 32 (1): 58-61 [Abstract] ( 570 ) HTML (1 KB)  PDF (631 KB)  ( 422 )
62 Traceability of Antenna Factor and Precision Calculable Dipole Antenna at 30 MHz~1 GHz
MENG Dong-lin,GAO Xiao-xun,XIE Ming
DOI: 10.3969/j.issn.1000-1158.2011.01.14
A set of calculable dipole antennas are developed from 30MHz to 1GHz, based on a set of commercially available precise dipole antennas and a set of specific S-parameters adaptors. The site insertion loss /site attenuation difference between simulating results and measurements is less than 0.9dB for different antenna heights, separations and frequencies. The antenna factor difference is less than 0.45dB accordingly. Because independent and more precise value can be computed from calculable dipole antennas, they are vital to solve the circular dilemma between OATS and antennas. The advantage of this solution is that calculable dipole antennas can be acquired based on some commercially available dipole antennas.
2011 Vol. 32 (1): 62-65 [Abstract] ( 703 ) HTML (1 KB)  PDF (906 KB)  ( 790 )
66 Independent Time Scale TA(NIM), Which is Steered by NIM5 Cesium Fountain Clock
GAO Yuan,GAO Xiao-xun,ZHANG Ai-min,WANG Wei-bo, NING Da-yu,LIU Nian-feng,WANG Ping,LIN Ping-wei,CHEN Wei-liang,LI Tian-chu,HUANG Yan
DOI: 10.3969/j.issn.1000-1158.2011.01.15
TA (NIM) is an independent atomic time scale. It is steered by a primary frequency standard that is NIM5 cesium fountain clock. The reference clock of TA (NIM) is an active hydrogen maser, which is measured and calibrated by the primary frequency standard periodically. A time scale algorithm can predict future frequency of the hydrogen maser, compensate frequency difference between the prediction and the calibration, and estimate the maser’s frequency when NIM5 fountain is not operational, in order to keep the frequency of TA(NIM) the same as the frequency of NIM5 fountain as much as possible. TA(NIM) began test run from August, 2007 and started to run formally from June, 2008. Data in recent more than one year show that TA(NIM) runs continuously, its time deviation (5 days) relative to TAI is 1.2 ns,and its frequency offset relative to TAI is 2.0×10-15.
2011 Vol. 32 (1): 66-69 [Abstract] ( 640 ) HTML (1 KB)  PDF (501 KB)  ( 561 )
70 Design of A Superconducting Microwave Cavity with High Quality Factor for Frequency Standard
WANG Nuan-rang,WU Qiong,YANG Ren-fu,NIAN Feng,GAO Lian-shan
DOI: 10.3969/j.issn.1000-1158.2011.01.16
To design a superconducting cavity with high quality factor for frequency standard, the parameters that affect the ability of the cavity are all achieved through theory analysis and computer program. A curve through which the temperature can be achieved for the aim is got through calculating the quality factor in different temperature. The parameters of cavity are as follows: the mode is TM010, the diameter is 60 mm, the height is 50 mm, the frequency is 4.4GHz, the quality factor is 3.9×107 and 1.9×109 when the temperature is 4.2K and 2K,respectively,which is close to the calculation.
2011 Vol. 32 (1): 70-74 [Abstract] ( 626 ) HTML (1 KB)  PDF (1117 KB)  ( 1111 )
75 Study of Stability and Consistency of Rubidium Atomic Clock
ZHONG Chong-xia,JIANG Dong-wei,YANG Jun
DOI: 10.3969/j.issn.1000-1158.2011.01.17
Study of stability and consistency of rubidium atomic clock was described. And comparison of methods to express frequency stability, comparison of stability of same rubidium atomic clock at different life-span, comparison of stability of multi rubidium atomic clocks of same model, study of stability, drift rate and consistency were analyzed in emphasis and detail.
2011 Vol. 32 (1): 75-79 [Abstract] ( 566 ) HTML (1 KB)  PDF (627 KB)  ( 773 )
80 A Physics Package with High S/N Ratio for Rubidium Atomic Frequency Standards
QI Feng,ZHAO Feng,WANG Fang,XIA Bai-hua,MEI Gang-hua
DOI: 10.3969/j.issn.1000-1158.2011.01.18
Physics package is the core of the atomic frequency standard. By analyzing the mechanism which Signal to Noise Ratio (SNR) of the atomic discrimination signal affect the frequency stability, a modified physics package was made. This physics package is designed according to the three cell scheme, in which a slotted tube microwave cavity and a rubidium spectrum lamp with Xe as the buffer gas were used. A preliminary test on the physics package was carried out, and a short term frequency stability of nearly 8×10-13/1s was achieved. This result shows that the frequency stability of an rubidium atomic frequency standard can be better than 1×10-12/τ(1/2), and there is still space to improve long term performance of the rubidium atomic frequency standard.
2011 Vol. 32 (1): 80-84 [Abstract] ( 456 ) HTML (1 KB)  PDF (1082 KB)  ( 692 )
85 Uncertainty Evaluation in Comparison of Ammonia Standard Gas by Spectrophotometry
XIAO An-shan,DING De-wu,CUI Tao,JIANG Su-xia,ZOU Bing
DOI: 10.3969/j.issn.1000-1158.2011.01.19
To study the repeatability and stability of ammonia standard gas produced by gravimetry, comparison of concentration by spectrophotometry is made and uncertainty of measurement is evaluated according to JJF1135—2005‘Evaluation of Uncertainty in Chemical Analysis Measurement’. The comparison result is (17.6 ±0.4)mg/m3,k=2 and it is consistent with the nominal value(17.6 mg/m3). The result shows that the comparison by spectrophotometry meets the requirement completely.
2011 Vol. 32 (1): 85-88 [Abstract] ( 451 ) HTML (1 KB)  PDF (290 KB)  ( 421 )
89 Uncertainty of Measurement in Determination of Melamine in Liquid Milk
KONG Xiao-ping;LI Bo;ZHU Qian,MENG Jie,XU Jian-jun
DOI: 10.3969/j.issn.1000-1158.2011.01.20
According to GB/T 22388—2008, melamine in liquid milk is detected with HPLC. The uncertainty of the measurement in determination of melamine in liquid milk is analyzed and processed by mathematical model. On the basis of analyzing the different parts of the uncertainty, the combined standard uncertainty and the expanded uncertainty are acquired, they are 0.054 mg/kg and 0.11 mg/kg respectively. The result shows that the major uncertainty of the measurements are comprised by the measurement repeatability of the sample solution and standard solution and the uncertainty leading by preparing sulation, the minor parts are the uncertainty leading by weighing and fixing of the samples.
2011 Vol. 32 (1): 89-92 [Abstract] ( 465 ) HTML (1 KB)  PDF (280 KB)  ( 493 )
93 Discussion on the Calculation Method for Reference Value and Degrees of Equivalence in Comparisons
YUAN Zun-dong,WANG Chi,LIN Yan-dong
DOI: 10.3969/j.issn.1000-1158.2011.01.21
Based on considering the correlation between the laboratory result and reference value, the weighted average method for calculating the reference value and the method for calculating the uncertainty of the degrees of equivalence are introduced. Furthermore,the uncertainty introduced in the comparison and correction process contributes to the weights calculating the weighted average method are presented. It is pointed out that the influence of correlation of the laboratory measured values on analyzing and calculating the uncertainty of the reference value or that of optimal estimated value of the external independent values should be considered.
2011 Vol. 32 (1): 93-96 [Abstract] ( 455 ) HTML (1 KB)  PDF (266 KB)  ( 643 )
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