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AbstractAbstract
[en] The study of the electronic relaxation by means of Moessbauer spectroscopy is reviewed. After a general discussion on the Moessbauer lineshape problem, the relaxation effects are considered within the stochastic and superoperators theories. Simulated and experimental relaxation spectra are also presented. (author)
Original Title
Forma liniei Moessbauer in prezenta relaxarii electronice
Source
78 refs.
Record Type
Journal Article
Journal
Studii si Cercetari de Fizica; v. 29(10); p. 1007-1035
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AbstractAbstract
[en] The basic principles that must be known to interpret NMR images, are exposed. After an analysis of the fundamental parameters (T1 and T2 relaxation time particularly), the main elements necessary to analyse a Spin Echo image are presented
[fr]
Nous exposons les principes de base indispensables a connaitre pour interpreter un document en IRM (Imagerie par Resonance Magnetique). Apres avoir analyse les parametres fondamentaux (temps de relaxation T1 et T2 en particulier), nous presentons les principales notions qui permettent de lire une image en Echo de SpinOriginal Title
Comment lire une image IRM
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Carvalho, J.G.; Medeiros, D.; Cabrera, G.G., E-mail: cabrera@ifi.unicamp.br2004
AbstractAbstract
[en] We solve the dynamics of quantum spin chains when the initial condition is prepared as a spatially inhomogeneous state of the magnetization. Particularly long-lived states are found for which the relaxation time diverges and the whole relaxation process slows down as a consequence of constructive interference at degenerate stationary points. These states may be of interest for performing quantum computation
Source
ICM 2003: International conference on magnetism; Rome (Italy); 27 Jul - 1 Aug 2003; S0304885303012940; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
Literature Type
Conference
Journal
Journal of Magnetism and Magnetic Materials; ISSN 0304-8853;
; CODEN JMMMDC; v. 272-276(6); p. 886-887

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Hong, L.; Novikov, V.N.; Sokolov, Alexei P.
Oak Ridge National Laboratory (United States). Funding organisation: SC USDOE - Office of Science (United States)2011
Oak Ridge National Laboratory (United States). Funding organisation: SC USDOE - Office of Science (United States)2011
AbstractAbstract
[en] Although fragility of glass forming liquids is traditionally related to cooperativity in molecular motion, the connection between those parameters remains unclear. In this paper we present the estimates of cooperativity (heterogeneity) length scale obtained from the boson peak spectra. We demonstrate that agrees well with the dynamic heterogeneity length scale for the structural relaxation estimated by 4- dimensional NMR, justifying the use of . Presented analysis of large number of materials reveals no clear correlation between and fragility. However, there is a strong correlation between the cooperativity volume 3 and the activation volume measured at Tg. This observation suggests that only the volume (pressure) dependence of structural relaxation time correlates directly with the cooperativity size. However, the pure thermal (energetic) contribution to the structural relaxation, the so-called isochoric fragility, exhibits no correlation to the heterogeneity length scale, or the amount of structural units in 3. The presented results call for a revision of traditional view on the role of cooperativity/heterogeneity in structural relaxation of glass forming systems.
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Source
KC0203010; ERKCC02; AC05-00OR22725
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Journal Article
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AbstractAbstract
[en] The authors present their preliminary experience in the characterization of atherosclerotic lesions and thrombi according to the parameters employed in MRI, namely longitudinal (T1) transversal (T2) relaxation times and proton density. (author). 8 refs.; 3 figs
Primary Subject
Source
Crepaldi, G. (Padua University (Italy). Internal Medicine Department); Gotto, A.M. (Methodist Hospital, Houston, TX (USA)); Manzato, E.; Baggio, G. (Padua University (Italy). Internal Medicine Department) (eds.); International Congress Series; no. 817; 886 p; ISBN 0 444 81078 1;
; 1989; p. 641-644; Excerpta medica; Amsterdam (Netherlands); 8. International symposium on atherosclerosis; Rome (Italy); 9-13 Oct 1988

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Book
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Blicharski, J.S.; Weglarz, W.; Wolak, A.; Pasterna, G.
Funding organisation: Polish Committee for Scientific Research, Warsaw (Poland)
Materials presented at the 26. All-Polish Seminar on the Nuclear Magnetic Resonance and its application1994
Funding organisation: Polish Committee for Scientific Research, Warsaw (Poland)
Materials presented at the 26. All-Polish Seminar on the Nuclear Magnetic Resonance and its application1994
AbstractAbstract
[en] The spin relaxation times for different molecular structures have been calculated. Calculated relaxation times as a function of temperature are presented
Original Title
Teoria magnetycznej relaksacji jadrowej w cieklych krysztalach
Source
Hennel, J.W. (comp.); Institute of Nuclear Physics, Cracow (Poland). Funding organisation: National Atomic Energy Agency, Warsaw (Poland); Polish Academy of Sciences, Warsaw (Poland); Bruker Analytische Messtechnik GmbH, Rheinstetten (Germany); Schering AG, Berlin (Germany); Siemens AG, Berlin (Germany); Varian Associates, Santa Clara, CA (United States); 511 p; 1994; p. 54-65; 26. All-Polish seminar on the nuclear magnetic resonance and its application; 26. Ogolnopolskie seminarium na temat magnetycznego rezonansu jadrowego i jego zastosowan; Cracow (Poland); 1-2 Dec 1993; KBN GRANT NO 224119102; 18 refs, 4 figs.
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Miscellaneous
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AbstractAbstract
[en] In this book it is explained how images are performed in nuclear magnetic resonance tomography. Therefore detailed discussions are deveted to the physical background, the possibilities for influencing of the images by the proper choice of pulse sequences, the spatial localization of the NMR signals and the clinical applications. (author). 323 refs.; 138 figs.; 2 tabs
Original Title
Inleiding in de kernspin tomografie (NMR imaging)
Primary Subject
Source
1985; 183 p; VU Uitgeverij; Amsterdam (Netherlands); ISBN 90-6256-246-9;
; Includes subject index.

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Book
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AbstractAbstract
[en] The decay of nuclear spin-spin energy has been studied in the mixed state of vanadium and anomalously rapid relaxation rates are found as compared to the rates for spin-lattice relaxation of Zeeman energy. The experiment was performed by adiabatically demagnetizing the spins in the rotating frame at a field larger than H/subc/2 and then cycling the field to bring the sample into the mixed state for a variable time. The residual dipolar energy is detected, once the field is raised, by adiabatically remagnetizing the sample on resonance. I show that the relaxation observed, after the vortices are pinned, is due to a cross relaxation of a spin energy associated with the magnetic field gradients in the mixed state and the dipolar energy which is in semiequilibrium with the quadrupole energy. This process is mediated by a current of magnetization, proportional to the diffusion coefficient D, which is driven by the field gradients and uses dipolar energy as a heat sink. Using a field distribution in the mixed state calculated by Marcus, I find D = 2.8 +- 0.9 x 10-12 cm2 sec-1 from the measurements of the relaxation rate of dipolar energy and of the quadrupole system heat capacity. This measurement of D is the first for a metal or for nuclei with I > 1/2 and is twice the value predicted by the moment-moment calculation of Redfield and Yu. In the presence of large field gradien-ts, dynamic quenching of the diffusion is observed
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Secondary Subject
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Journal Article
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Phys. Rev., B; v. 13(1); p. 68-80
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AbstractAbstract
No abstract available
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Journal Article
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Solid State Communications; v. 11(5); p. 747-749
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AbstractAbstract
[en] The effect of a finite polarisation relaxation time on the transverse structure of the optical field of a wide-aperture laser is considered. The conditions are found for the emergence of periodic autowaves for positive and negative frequency detuning. These conditions are shown to depend strongly on the cross-relaxation rate. It is established that the dynamics of finite-aperture lasers at high cross-relaxation rates is satisfactorily described by simplified models in which the polarisation is adiabatically eliminated. (lasers)
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Source
Available from http://dx.doi.org/10.1070/QE2004v034n08ABEH002663; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
Journal
Quantum Electronics (Woodbury, N.Y.); ISSN 1063-7818;
; v. 34(8); p. 731-735

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