resistive;
hybrid magnet;
high field;
high resolution;
MAS;
ferromagnetic shim;
field homogeneity;
stability;
HENPEC;
NHMFL;
D O I:
10.1016/j.jmr.2007.12.008
中图分类号:
Q5 [生物化学];
学科分类号:
071010 ;
081704 ;
摘要:
Resistive and resistive-superconducting hybrid magnets can generate dc magnetic fields much higher than conventional superconducting NMR magnets but the field spatial homogeneity and temporal stability are usually not sufficient for high-resolution NMR experiments. Hardware and technique development addressing these issues are presented for high-resolution NMR at magnetic fields up to 40 T. Passive ferromagnetic shimming and magic-angle spinning are used effectively to reduce the broadening from inhomogeneous magnetic field. A phase correction technique based on simultaneous heteronuclear detection is developed to compensate magnetic field fluctuations to achieve high spectral resolution. (C) 2008 Elsevier Inc. All rights reserved.