scholarly journals Pressure and temperature dependence of the longitudinal proton relaxation times in supercooled water to −87 °C and 2500 bar

1977 ◽  
Vol 67 (2) ◽  
pp. 718-723 ◽  
Author(s):  
E. Lang ◽  
H.‐D. Lüdemann
Keyword(s):  
Temperature Dependence ◽  
Relaxation Times ◽  
Supercooled Water ◽  
Proton Relaxation

Temperature Dependence of Proton Relaxation Times in Aqueous Solutions of Paramagnetic Ions

1959 ◽  
Vol 30 (4) ◽  
pp. 950-956 ◽  
Author(s):  
Robert A. Bernheim ◽  
Thomas H. Brown ◽  
H. S. Gutowsky ◽  
D. E. Woessner
Keyword(s):  
Aqueous Solutions ◽  
Temperature Dependence ◽  
Relaxation Times ◽  
Proton Relaxation ◽  
Paramagnetic Ions

Protonenspinrelaxation von Benzol an Silikageloberflächen

1968 ◽  
Vol 23 (3) ◽  
pp. 339-347
Author(s):  
D. Michel
Keyword(s):  
Temperature Dependence ◽  
Magnetic Relaxation ◽  
Spin Echo ◽  
Relaxation Times ◽  
Proton Relaxation ◽  
Relaxation Rates ◽  
Proton Proton ◽  
Proton Interaction ◽  
Paramagnetic Impurities ◽  
Hydroxyl Protons

Using spin-echo-techniques the temperature dependence of the proton magnetic relaxation times T1 and T2 of adsorbed benzene has been measured in the interval between +70 °C and —140 °C. Normal benzene C6H6 and mixtures of benzene and C6D6e were adsorbed on two sorts of silicagels which have been described elsewhere 4,9.The effective nuclear magnetic relaxation rates of adsorbed benzene are given by four contributions: the intramolecular proton-proton interaction, the interaction between benzene protons and paramagnetic impurities of the adsorbents, the interaction between benzene protons and hydroxyl protons on the silicagel surface, and the intermolecular interaction between benzene protons. These proton relaxation mechanisms depend differently on the H/D-ratio in C6H6—C6D6 mixtures (see section 4.1).The temperature dependence of the contributions 1/T1 intra and 1/T2 intra due to intramolecular proton-proton interaction suggests an anisotropic rotation of benzene molecules on the gel used. Furthermore, the existence of three different regions for the adsorbed benzene molecules has been inferred (see sections 4.2 and 5).

Cellular water and proton relaxation times of Thai rice kernels during grain development and storage

2019 ◽  
Vol 88 ◽  
pp. 65-70 ◽  
Author(s):  
Klitsadee Yubonmhat ◽  
Suriya Chinwong ◽  
Nattawoot Maleelai ◽  
Nath Saowadee ◽  
Wiwat Youngdee
Keyword(s):  
Relaxation Times ◽  
Proton Relaxation ◽  
Grain Development ◽  
Cellular Water ◽  
And Storage

Bonded Hydrogen and Trapped H2 in a-Si1−xGex:H Alloys

1989 ◽  
Vol 149 ◽  
Author(s):  
E. J. Vanderheiden ◽  
G. A. Williams ◽  
P. C. Taylor ◽  
F. Finger ◽  
W. Fuhs
Keyword(s):  
Temperature Dependence ◽  
Molecular Hydrogen ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
H Nmr ◽  
Local Environments

ABSTRACT1H NMR has been employed to study the local environments of bonded hydrogen and trapped molecular hydrogen (H2) in a series of a-Si1−xGex:H alloys. There is a monotonic decrease of bonded hydrogen with increasing x from ≈ 10 at. % at x = 0 (a-Si:H) to ≈ 1 at. % at x = 1 (a-Ge:H). The amplitude of the broad 1H NMR line, which is attributed to clustered bonded hydrogen, decreases continuously across the system. The amplitude of the narrow 1H NMR line, which is attributed to bonded hydrogen essentially randomly distributed in the films, decreases as x increases from 0 to ≈ 0.2. From x = 0.2 to x ≈ 0.6 the amplitude of the narrow 1H NMR line is essentially constant, and for x ≥ 0.6 the amplitude decreases once again. The existence of trapped H2 molecules is inferred indirectly by their influence on the temperature dependence of the spin-lattice relaxation times, T1. Through T1, measurements it is determined that the trapped H2 concentration drops precipitously between x = 0.1 and x = 0.2, but is fairly constant for 0.2 ≤ x ≤ 0.6. For a-Si:H (x = 0) the H2 concentration is ≈ 0.1 at. %, while for x ≥ 0.2 the concentration of H2 is ≤ 0.02 at. %.

Temperature Dependence of Dynamic Properties of Elastomers. Relaxation Distributions

1952 ◽  
Vol 25 (4) ◽  
pp. 720-729 ◽  
Author(s):  
John D. Ferry ◽  
Edwin R. Fitzgerald ◽  
Lester D. Grandine ◽  
Malcolm L. Williams
Keyword(s):  
Distribution Function ◽  
Temperature Dependence ◽  
Dynamic Properties ◽  
Relaxation Times ◽  
Dynamic Mechanical Properties ◽  
Relaxation Processes ◽  
The Real ◽  
Reduced Frequency ◽  
Dynamic Rigidity ◽  
Composite Curve

Abstract By the use of reduced variables, the temperature dependence and frequency dependence of dynamic mechanical properties of rubberlike materials can be interrelated without any arbitrary assumptions about the functional form of either The definitions of the reduced variables are based on some simple assumptions regarding the nature of relaxation processes. The real part of the reduced dynamic rigidity, plotted against the reduced frequency, gives a single composite curve for data over wide ranges of frequency and temperature; this is true also for the imaginary part of the rigidity or the dynamic viscosity. The real and imaginary parts of the rigidity, although independent measurements, are interrelated through the distribution function of relaxation times, and this relation provides a check on experimental results. First and second approximation methods of calculating the distribution function from dynamic data are given. The use of the distribution function to predict various types of time-dependent mechanical behavior is illustrated.

Proton relaxation times in7LiCl and6LiCl solutions

1967 ◽  
Vol 13 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Burton P. Fabricand ◽  
Sigmund S. Goldberg
Keyword(s):  
Relaxation Times ◽  
Proton Relaxation

Effect of Motion on the Sonographic and Magnetic Resonance Patterns of Ageing Blood

1986 ◽  
Vol 27 (4) ◽  
pp. 455-458 ◽  
Author(s):  
A. Alanen ◽  
P. Nummi
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Times ◽  
Large Change ◽  
Proton Relaxation ◽  
Mechanical Motion ◽  
Microscopic Appearance ◽  
Histologic Appearance ◽  
Blood Clots ◽  
T1 And T2

The sonographic appearance of a hematoma may be affected by various factors, including the age of the hematoma. The effect of mechanical motion on the echogenicity and histologic appearance, and on the proton relaxation times T1 and T2 of blood clots, was studied in vitro for up to 21 days. All clots were of similar echogenicity and microscopic appearance during the first 2 days. The minimally disturbed clots were sonolucent from day 4 onwards, whereas moderate mechanical disturbance changed the microscopic structure of the blood clots and caused them to retain their echogenicity. Proton relaxation times T1 and T2 of both minimally disturbed and vigorously manipulated blood samples showed a rapid shortening of T1 and a less marked decrease of T2 between days 1 and 4, which was independent of mechanical motion. The ultrasonic appearance reflected the histologic appearance but not necessarily the age of the clot. The magnetic resonance (MR) parameters T1 and to a lesser extent T2 accurately reflected the age of the clot during the first 6 days. Although relatively gentle motion caused a large change in the ultrasonic appearance of the clots, vigorous shaking did not affect the magnetic resonance appearance of human blood clots.

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