摘要:

AbstractA practical introduction to coherence and coherence transfer pathways in NMR is provided using the density matrix and product‐operator formalisms. The concept of coherence in NMR is first introduced using the density matrix formalism. Pictorial and quantitative representations of coherence are provided using product operators in the Cartesian basis. A simple transformation from the Cartesian basis to a spherical basis is used to follow coherence order during multiple‐pulse experiments with coherence transfer pathways. The rules are introduced for designing phase cycles to eliminate unwanted coherences and pathways. An appendix contains a computer program written inMathematicafor performing product‐operator calculations interact

ISSN:1043-7347    

DOI:10.1002/cmr.1820040102

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe shielding tensor can be nonsymmetric and thus in general has both symmetric and antisymmetric parts. Relaxation by these two parts of the shielding tensor (chemical shift anisotropy or CSA relaxation) are reviewed and compared with relaxation by the dipole‐dipole (DD) mechanism. It is explained how T2can be equal to (6/7)T1or to 2T1in limiting situations for relaxation that involves the shielding tensor. Cross‐correlation (or interference) effects between CSA and DD relaxation and the relationship between CSA and spin‐rotation relaxation are briefly rev

ISSN:1043-7347    

DOI:10.1002/cmr.1820040103

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractDifferentiation between fat and water is important in proton magnetic resonance imaging. The need for creating separate fat and water images is discussed, and a review is presented of current practices, including chemical‐shift and coupled‐spin imaging, as well as techniques based on relaxation time differences. The virtues and limitations of each regime are discussed, and future directions are sugges

ISSN:1043-7347    

DOI:10.1002/cmr.1820040104

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

ISSN:1043-7347    

DOI:10.1002/cmr.1820040101

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY