scholarly journals Quasiparticle relaxation rate and shear viscosity of superfluid -A1 at low temperatures

2004 ◽  
Vol 348 (1-4) ◽  
pp. 108-114 ◽  
Author(s):  
M.A. Shahzamanian ◽  
R. Afzali
Keyword(s):  
Relaxation Rate ◽  
Shear Viscosity ◽  
Low Temperatures ◽  
Quasiparticle Relaxation

Low temperatures shear viscosity of a two-component dipolar Fermi gas with unequal population

2016 ◽  
Vol 370 ◽  
pp. 105-116
Author(s):  
E. Darsheshdar ◽  
H. Yavari ◽  
Z. Zangeneh
Keyword(s):  
Shear Viscosity ◽  
Low Temperatures ◽  
Fermi Gas ◽  
Two Component

Bewegungen der CH3-Gruppen in Methyl-Naphtalin-Kristallen .III.Protonenspin-Relaxation bei tiefen Temperaturen / Rotation of CH3 Croups in Methyl Naphthalene Crystals at low Temperatures

1973 ◽  
Vol 28 (1) ◽  
pp. 69-76 ◽  
Author(s):  
J. U. von Schütz ◽  
W. Güttler ◽  
H. C. Wolf
Keyword(s):  
Relaxation Time ◽  
Relaxation Rate ◽  
Low Temperatures ◽  
Methyl Groups ◽  
Longitudinal Relaxation Time ◽  
Kcal Mole ◽  
Temperature Range ◽  
Longitudinal Relaxation ◽  
Comparison Of The Results ◽  
Methyl Naphthalene

In continuation of earlier works (temperature range 400 - 77 K) the temperature and frequency dependencies of the longitudinal relaxation time T1 in different methyl naphthalene crystals were measured down to 4,2 K at 22 and 56 MHz. The observation of two minima in some cases below 50 K could be attributed quantitatively to the weakly hindered β-CH3 groups (EA <0,8 kcal/mole) by comparison of the results of similar methyl naphthalenes. The low relaxation rate in the minima is due to tunneling effects of the methyl groups. The splitting of the lowest torsional niveau could be roughly determined.

scholarly journals Effective Radii of Macromolecules in Dilute Polyvinyl Alcohol Solutions

2018 ◽  
Vol 63 (2) ◽  
pp. 144 ◽  
Author(s):  
O. V. Khorolskyi
Keyword(s):  
Experimental Data ◽  
Polyvinyl Alcohol ◽  
Dimethyl Sulfoxide ◽  
Temperature Interval ◽  
Shear Viscosity ◽  
Low Temperatures ◽  
Concentration Dependences ◽  
Concentration Interval ◽  
Temperature Dependences ◽  
Pva Solutions

The temperature and concentration dependences of the effective radii of polyvinyl alcohol (PVA) macromolecules have been studied on the basis of experimental data on the viscosity of dilute PVA solutions in dimethyl sulfoxide (DMSO) and water, as well as using the Malomuzh–Orlov theory of shear viscosity in polymer solutions. The temperature dependences of the effective radii of PVA macromolecules in DMSO are shown to be linear in the temperature interval 293÷353 K. At the same time, those dependences are more complicated for aqueous PVA solutions. Namely, the effective radii of macromolecules remain unchanged at relatively low temperatures and PVA concentrations, but they decrease nonlinearly at higher temperatures and concentrations. The concentration dependences of the effective radii of PVA macromolecules in both solvents are found to decrease nonlinearly in the concentration interval 0.3–3 wt.%.

The nuclear spin-lattice relaxation of an amorphous Hubbard model

1994 ◽  
Vol 72 (9-10) ◽  
pp. 658-667
Author(s):  
K. L. Liu
Keyword(s):  
Hubbard Model ◽  
Temperature Dependence ◽  
Relaxation Rate ◽  
Nuclear Spin ◽  
Low Temperatures ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

We study the temperature dependence of the nuclear spin-lattice relaxation rate, (1/T1), of a structurally disordered Hubbard model for different electronic concentration ne, and for various interaction strength U. The relaxation process is assumed to be caused by the hyperfine Fermi contact interaction. The required electronic spin correlation function is studied up to the fourth order in hopping, and a Gaussian approximation is constructed. Two types of transfer integral have been examined: (1) quasi-exponential, and (2) Gaussian. At half-filling (ne = 1), the relaxation rate shows a strong U dependence at low temperatures. For large U, (1/T1) drops markedly when holes are introduced into the system at low temperatures, and its temperature dependence becomes weak when ne reaches 0.8. We also calculate the spin susceptibility and examine the ne dependence of the Korringa relation. We compare the relaxation rates with those for the two-dimensional Hubbard model with nearest-neighbor hopping on a square lattice, and contact is made with the recent NMR study of Sr-doped La2CuO4 at high temperatures.

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