Dislocation Dynamics In B.C.C. Metals: A Nuclear Magnetic Resonance and Transmission Electron Microscopic Study

1990 ◽  
Vol 209 ◽  
Author(s):  
J. Th. M. De Hosson ◽  
O. Kanert
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dislocation Dynamics ◽  
Electron Microscopic ◽  
Static Structure ◽  
Transmission Electron ◽  
Jump Distance ◽  
Transmission Electron Microscopic ◽  
The Mean ◽  
Nuclear Magnetic

ABSTRACTPulsed nuclear magnetic resonance proved to be a complementary new technique for the study of moving dislocations in b.c.c. metals. From the motion induced part of the spin-lattice relaxation rate the mean jump distance of mobile dislocationshas been measured in Vanadium as a function of temperature. The NMR experiments are combined with transmission electron microscopic investigations to reveal the static structure of defects in the samples. The NMR experiments show that the mean jump distance is nearly constant below 230 K whereas it decreases substantially above 230 K to 300 K indicating a transition that marks two different mechanisms. NMR observations in combination with TEM support the physical picture that above that transition temperature dislocation segments are stopped between localized obstacles whereas below Tc the latticefriction controls the plastic behaviour.

Dislocation Dynamics Investigated by Means of Nuclear Magnetic Resonance a Complementarynew Technique

1986 ◽  
Vol 82 ◽  
Author(s):  
J. Th. M. De Hosson ◽  
O. Kanert
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lattice Relaxation ◽  
Dislocation Dynamics ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Jump Distance ◽  
Relaxation Measurements ◽  
The Mean ◽  
Nuclear Magnetic

ABSTRACTPulsed nuclear magnetic resonance proved to be a new complementary technique for the study of moving dislocations in Al—base alloys. Spin—lattice relaxation measurements clearly indicate that fluctuations in the quadrupolar field caused by moving dislocations in Al—base alloys are different compared to those in ultra—pure Al. From the motion induced part of the spin—lattice relaxation rate the mean jump distance of mobile dislocations has been determined as a function of strain. Measurements have been performed on Al—Cu, Al—Li and Al—Zn binary alloys. Asa typical illustration of the strength of this technique, this paper reports the resultsobtained of Al—(1—2 at%) Zn solid solution.

scholarly journals Dislocation dynamics in Al–Mg–Zn alloys: A nuclear magnetic resonance and transmission electron microscopic study

1988 ◽  
Vol 3 (4) ◽  
pp. 645-650 ◽  
Author(s):  
J. Th. M. De Hosson ◽  
O. Kanert ◽  
U. Schlagowski ◽  
G. Boom
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Striking Difference ◽  
Spin Lattice ◽  
Transmission Electron ◽  
The Mean ◽  
Zn Alloys ◽  
Nuclear Magnetic

Pulsed nuclear magnetic resonance (NMR) proved to be a complementary new technique for the study of moving dislocations in Al–Mg–Zn alloys. The NMR technique, in combination with transmission electron microscopy (TEM), has been applied to study dislocation motion in Al–0.6 at. % Mg–1 at. % Zn and Al–2 at. % Mg–2.5 at. % Zn. Spin-lattice relaxation measurements clearly indicate that fluctuations in the nuclear quadrupolar interactions caused by moving dislocations in Al–Mg–Zn are different compared to those in ultra pure Al. From the motion induced part of the spin-lattice relaxation rate the mean jump distance of mobile dislocations has been determined as a function of strain. From the NMR data it is concluded that moving dislocations advance over a number of solute atoms in these alloys as described by Mott-Nabarro's model. At large strains there exists a striking difference between the mean jump distances in Al–0.6 at. % Mg–1 at. % Zn and in Al–1.2 at. % Mg–2.5 at. % Zn. The latter is about five times smaller than the former one. This is consistent with TEM observations that show dislocation cell formation only in Al–0.6 at. % Mg-1 at. % Zn and the macroscopic stress-strain dependences of these alloys.

Stability-Indicating Proton Nuclear Magnetic Resonance Spectroscopic Assay Method for Furosemide in Tablets and Injections

1993 ◽  
Vol 76 (3) ◽  
pp. 526-530 ◽  
Author(s):  
George M Hanna ◽  
Cesar A Lau-Cam
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Degradation Product ◽  
Spectroscopic Method ◽  
Internal Standard ◽  
Butyl Alcohol ◽  
Proton Nuclear Magnetic Resonance ◽  
Assay Method ◽  
The Mean ◽  
Nuclear Magnetic

Abstract A simple, specific, and accurate proton nuclear magnetic resonance (1H-NMR) spectroscopic method has been developed for the identification and assay of furosemide and its degradation product, 4-chloro-5-sulfamoylanthranilic acid (CSA), in tablets and injections. Dissolution of the sample in D20-NaOD resulted in a solution yielding the required separation among the resonance signals of furosemide, CSA, and ferf-butyl alcohol, the internal standard. The mean ± SD recovery values of furosemide and CSA from 10 synthetic formulations were 99.6 ± 0.8 and 98.9 ± 1.7%, respectively. Commercial tablets (6 lots) and injections (5 lots) of furosemide were assayed by the proposed method and found to contain 53.1-99.8% furosemide and 0.3-45.2% CSA.

Sign in / Sign up

Export Citation Format

Share Document