caa a22 4500 445381604 CHVBK 20180317143019.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s10948-010-0877-7 doi (NATIONALLICENCE)springer-10.1007/s10948-010-0877-7 A Ferromagnetic Shimming Method for NMR/MRI Magnets Adopting Two Consecutive Optimization Techniques: LinearProgramming and Evolution Strategy [Elektronische Daten] [Sangjin Lee, Seungyong Hahn, Kideok Sim] Shimming is very important for nuclear magnetic resonance (NMR) magnets because image resolution is highly dependent on the homogeneity of the magnetic field. There are two types of shimming: active and passive. Active shimming is done using coils with adjustable current. Passive shimming involves pieces of steel with good magnetic qualities. The steel pieces are placed near a superconducting magnet. They are magnetized and produce their own magnetic field. Additional magnetic fields (produced by coils or steel) add to the original magnetic field of the superconducting magnet in such a way that the total field becomes more homogeneous. In this paper, we developed a passive shimming method adopting consecutive optimization techniques, i.e., linear programming (LP) and evolution strategy (ES). The LP is relatively fast and mostly guarantees a global minimum for a linear problem, whereas the ES is easy to formulate and can digitize design variables. So we suggested an optimization method combining both the LP and the ES consecutively for passive shimming of NMR magnets. Springer Science+Business Media, LLC, 2010 NMR/MRI magnet nationallicence Ferromagnetic shimming nationallicence Passive shimming nationallicence Linear programming nationallicence Evolution strategy nationallicence Lee Sangjin Department of Electrical Eng., Uiduk University, 780-713, Gyeongju, Korea aut Hahn Seungyong Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut Sim Kideok Superconductivity Research Center, KERI, 641-120, Changwon, Korea aut Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/1-2(2011-01-01), 1037-1043 1557-1939 24:1-2<1037 2011 24 10948 https://doi.org/10.1007/s10948-010-0877-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10948-010-0877-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lee Sangjin Department of Electrical Eng., Uiduk University, 780-713, Gyeongju, Korea aut NATIONALLICENCE 700 1- Hahn Seungyong Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut NATIONALLICENCE 700 1- Sim Kideok Superconductivity Research Center, KERI, 641-120, Changwon, Korea aut NATIONALLICENCE 773 0- Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/1-2(2011-01-01), 1037-1043 1557-1939 24:1-2<1037 2011 24 10948 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer