Symmetry in the design of NMR multiple-pulse sequences.

Symmetry principles for the design of radiofrequency pulse sequences in the nuclear magnetic resonance of rotating solids

Some new symmetry theorems are presented which simplify the task of designing multiple-pulse radio-frequency pulse sequences in magic-angle-spinning solid-state NMR. The symmetry theorems apply to sequences denoted R N, which n consists of N repetitions of a pulse sequence element R, alternating in phase between the values "pnrN. Each R element ideally rotates the spins by an angle p about the ...

The Optimization of Magnetic Resonance Imaging Pulse Sequences in Order to Better Detection of Multiple Sclerosis Plaques

Background and objective: Magnetic resonance imaging (MRI) is the most sensitive technique to detect multiple sclerosis (MS) plaques in central nervous system. In some cases, the patients who were suspected to MS, Whereas MRI images are normal, but whether patients don’t have MS plaques or MRI images are not enough optimized enough in order to show MS plaques? The aim of the current study is ...

A fast, stable quadrature phase generator for multiple-pulse NMR

Modern NMR pulse sequences usually consist of a series of radiofrequcncy (rf) pulscs having orthogonal (quadrature) phases. While there are a variety of situations where pulse accuracy is important, 1 it is especially critical for solid-state multiple-pulse NMR.2 In fact, multiple pulse sequences developed for phase measurement excced the accuracy of traditional electronic phase measuremen t te...

Symmetry-Based Pulse Sequences in Magic-Angle Spinning Solid-State NMR

Optimal control of coupled spin dynamics: design of NMR pulse sequences by gradient ascent algorithms.

In this paper, we introduce optimal control algorithm for the design of pulse sequences in NMR spectroscopy. This methodology is used for designing pulse sequences that maximize the coherence transfer between coupled spins in a given specified time, minimize the relaxation effects in a given coherence transfer step or minimize the time required to produce a given unitary propagator, as desired....