。1050· 北京科技大学学报 第29卷 [8]Ding H S.Zhang F H.Yan X M,et al.A scanning SQUID mi- tow-dimensional current distribution.J Appl Phys.1989.65 croscope for room temperature samples.Chin Phys 2002.11 (1):361 (11):1135 【Ig陈兆斗，申亚男.Col一Tukey FFT在高维的算法.计算数 [9]Bradley J R.Sepulveda N G.Using a magnetometer to image a 学，2004.26(2)：137 M agnetism-current inverse in high-temperature superconducting quantum interfer- ence device magnetic field measurement FENG Mengli,DING Hongsheng,SUN Jingchun Appied Science School,University of Science and Technology Beijing.Bijng 100083.China ABSTRACT Based on the Biot-Savart law,spatial filtering technology and two-dimensional Fourier transfom, the inverse problem of magnetic field to current distribution was researched.The inverse method was applied to the real magnetic field data measured by a high-temperature superconducting quantum interference device (SQUID),and the magnetic field was produced by a lead with current and vortex around a columniform crack. The inverse results,especially how to select the filtering frequency in a Fourier space,were discussed.The re- sults show that a larger cutoff frequency can improve the spatial resolution of the current image,but increase the noise signal.If a smaller cutoff frequency is selected,much of the noise can be eliminated,but the resulted in- verse signal will be anamorphic,and the spatial resolution is decreased.Using the magnetic field data excited by vortex around a column form defect,the inversed current result can give the infommation about the location and the form of the defect exactly. KEY WORDS superconducting quantum interference device (SQU ID);magnetic field measurement;nonde- structive evaluation(NDE);inverse (上接第1036页) Effect of roll contour configuration on the flatness control performance of non-ori- ented electrical steel sheets in hot rolling CAO Jianguo,WEI Gangcheng2),ZHANGJie,SUYi),CHEN Gang2) 1)Mechanical Engineering School,University of Science and Technology Beijing,Beijing 100083.China 2)Wuhan I mn and Steel Company,Wuhan 430083.China ABSTRACT The roll contour variation characteristics of conventional backup and work rolls,self-developed VCR (varying contact backup rolls)and ASR (asymmetry self-compensating work rolls)were investigated by industrial test results.The finite element models of three typical roll contour configurations,i.e.conventional backup/work rolls,VCR/conventional work rolls,and VCR/ASR,were developed to calculate the rollstack de- formation.The flatness control performance of these roll contour configurations was analy zed.In comparison with the conventional roll contour configuration,the crown control range by roll bending force enhances by 12 79%and the roll gap stiffness increases by 25.30%.The peak values of roll contact pressure in the prophase and anaphase rolling service drop by 40.23%and 41.40%0,respectively.The application of VCR/ASR configu- ration gives better strip profile and flatness quality,an increase in coil number within the rolling campaign and a significant alleviated effect of severe work roll wear contour on the perfomance of edge drop control in a 1 700 mm hot strip mill at WIS(G)CO of China. KEY WORDS hot rolling;strip:wear;finite element analysis;flatness control[ 8] Ding H S , Zhang F H, Yan X M, et al.A scanning SQUID mi￾croscope for room temperature samples.Chin Phys, 2002, 11 ( 11) :1135 [ 9] Bradley J R, Sepulveda N G .Using a magnetometer to image a tow-dimensional current distributi on.J Appl Phys, 1989, 65 ( 1) :361 [ 10] 陈兆斗, 申亚男.Cooley-Tukey FFT 在高维的算法.计算数 学, 2004, 26( 2) :137 Magnetism-current inverse in high-temperature superconducting quantum interfer￾ence device magnetic field measurement FENG Mengli, DING Hongsheng, SUN Jingchun Applied S cience School, University of Science and T echnology Beijing, Beijing 100083, China ABSTRACT Based on the Biot-Savart law , spatial filtering technology and two-dimensional Fourier transfo rm, the inverse problem of magnetic field to current distribution w as researched .The inverse method was applied to the real magnetic field data measured by a high-temperature superconducting quantum interference device ( SQUID) , and the magnetic field w as produced by a lead w ith current and vortex around a columniform crack . The inverse results, especially how to select the filtering frequency in a Fourier space, were discussed .The re￾sults show that a larger cutoff frequency can improve the spatial resolution of the current image, but increase the noise signal.If a smaller cutoff frequency is selected, much of the noise can be eliminated, but the resulted in￾verse signal w ill be anamorphic, and the spatial resolution is decreased .Using the magnetic field data excited by vo rtex around a column form defect, the inversed current result can give the information about the location and the form of the defect exactly . KEY WORDS superconducting quantum interference device ( SQU ID) ;magnetic field measurement ;nonde￾structive evaluation( NDE) ;inverse ( 上接第 1036 页) Effect of roll contour configuration on the flatness control performance of non-ori￾ented electrical steel sheets in hot rolling CAO Jianguo 1) , WEI Gangcheng 1, 2) , ZHANGJ ie 1) , S U Y i 2) , CHEN Gang 2) 1) Mechanical Engineering S chool, University of Sci ence and Technology Beijing, Beijing 100083, China 2) Wuhan I ron and St eel Company, Wuhan 430083, China ABSTRACT The roll contour variation characteristics of conventional backup and work rolls, self-developed VCR ( varying contact backup rolls) and ASR ( asymmetry self-compensating wo rk rolls) w ere investig ated by industrial test results.The finite element models of three typical roll contour configurations, i .e .conventional backup/wo rk rolls, VCR/ conventional w ork rolls, and VCR/ASR, w ere developed to calculate the roll stack de￾formation .The flatness control performance of these roll contour configurations w as analy zed .In comparison w ith the conventional roll contour configuration, the crown control range by roll bending fo rce enhances by 12.79 %and the roll gap stiffness increases by 25.30 %.The peak values of roll contact pressure in the prophase and anaphase rolling service drop by 40.23 %and 41.40 %, respectively .The application of VCR/ASR configu￾ration gives better strip profile and flatness quality, an increase in coil number within the rolling campaign and a significant alleviated effect of severe w ork roll w ear contour on the perfo rmance of edge drop control in a 1 700 mm hot strip mill at WIS( G) CO of China. KEY WORDS hot rolling ;strip ;wear;finite element analysis ;flatness control · 1050 · 北 京 科 技 大 学 学 报 第 29 卷