Topic
Relaxation (NMR)
About: Relaxation (NMR) is a research topic. Over the lifetime, 29342 publications have been published within this topic receiving 689851 citations.
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TL;DR: In this article, a pictorial description of rapid multipulse imaging ex- periments is given, and an extension of this theory applied to modern imaging sequences such as TRUE FISP and rf-spoiled techniques.
Abstract: Magnetic resonance imaging in biochemical and clinical research requires rapid imaging sequences. Time-resolved imaging of heart movement and the acquisition of a three-dimensional image block within the circulation time of a contrast agent bolus are two typical examples. Rapid imaging sequences are characterized by a very fast train of radiofre- quency (rf) and gradient pulses. Between these rf pulses, the excited magnetization is unable to return to its thermal equilibrium. As a consequence, further rf pulses will influence both the remaining transversal and the remaining equilibrium state. The steady-state magnetization of a multi-rf pulse and gradient pulse experiment is thus a mixture or superposition of different transversal and longitudinal states and the acquired image amplitude becomes a complex func- tion of the investigated tissue's relaxation properties. Based on the works of Woessner, Kaiser, and Hennig, this article intends to give a pictorial description of rapid multipulse imaging ex- periments. It also provides an extension of this theory applied to modern imaging sequences such as TRUE FISP and rf-spoiled techniques. © 1999 John Wiley & Sons, Inc. Concepts Magn Reson 11: 291-304, 1999.
183 citations
TL;DR: In this article, a general solution for the ground state spin in any given electric-magnetic-strain field configuration was obtained for the first time, and the influence of the fields on the evolution of the spin was examined.
Abstract: The ground state spin of the negatively charged nitrogen-vacancy center in diamond has many exciting applications in quantum metrology and solid state quantum information processing, including magnetometry, electrometry, quantum memory and quantum optical networks. Each of these applications involve the interaction of the spin with some configuration of electric, magnetic and strain fields, however, to date there does not exist a detailed model of the spin's interactions with such fields, nor an understanding of how the fields influence the time-evolution of the spin and its relaxation and inhomogeneous dephasing. In this work, a general solution is obtained for the spin in any given electric-magnetic-strain field configuration for the first time, and the influence of the fields on the evolution of the spin is examined. Thus, this work provides the essential theoretical tools for the precise control and modeling of this remarkable spin in its current and future applications.
183 citations
TL;DR: The oxide surface itself is an unexpectedly good relaxer of fluid-borne nuclear spins in the absence of paramagnetic ions, and the results answer some long-standing questions connected with the NMR properties of fluids-saturated sedimentary rocks.
183 citations
TL;DR: In this paper, the authors proposed a nonadiabatic multi-phonon process in the strong coupling limit, in which the low-temperature tunnelling rate increases exponentially with the zero point energy difference between the two states.
183 citations
TL;DR: The phenomenology of the glass transition is briefly reviewed in this article, where four classes of theories for the transition are discussed: rheological theories that account for the temperature dependence of the viscosity and/or relaxation time τ p, kinetic theories that predict the form of the relaxation function M p, relaxation theories that explain both the form and the temperature dependent of τ p ; and phenomenological theories describe the kinetics of relaxation without reference to a microscopic model.
Abstract: The phenomenology of the glass transition is briefly reviewed. Four classes of theories for the transition are discussed: rheological theories that account for the temperature dependence of the viscosity and/or relaxation time τ p ; kinetic theories that predict the form of the relaxation function M p ; relaxation theories that explain both the form of M p and the temperature dependence of τ p ; and phenomenological theories that describe the kinetics of relaxation without reference to a microscopic model.
183 citations