Determination of Two‐ and Three‐Body Relaxation Times from Collision‐Induced Absorption

1967 ◽  
Vol 46 (5) ◽  
pp. 1557-1561 ◽  
Author(s):  
George Birnbaum ◽  
Howard B. Levine ◽  
Donald A. McQuarrie
Keyword(s):  
Relaxation Times ◽  
Induced Absorption ◽  
Three Body

Collision Induced Absorption in N2, CO2, and H2 at 2.3 cm−1

1975 ◽  
Vol 53 (18) ◽  
pp. 1764-1776 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
J. L. Urbaniak
Keyword(s):  
Microwave Absorption ◽  
Loss Factor ◽  
Relaxation Times ◽  
Virial Coefficients ◽  
Low Frequency ◽  
Frequency Region ◽  
Induced Absorption ◽  
Three Body ◽  
Initial Measurement

Collision induced microwave absorption is reported in pure N2, CO2, and H2 in the region of 2.3 cm−1. For N2 the results are taken at temperatures ranging from 208 to 333 K and at densities ranging from 50 to 300 amagat. The parts of the loss factor which are proportional to the square and the cube of the density are found to depend respectively on T−1.55±0.12 and T−2.56±0.44. These results are well explained by the theory which relates the virial coefficients and relaxation times to the loss factor. Both the two and three body relaxation times, τ2 and τ3 follow very closely a T−0.5 dependence. The ratio of τ2/τ3 is found to be 0.83. For CO2 the results are taken at temperatures ranging from 273 to 363 K and at densities ranging from 8 to 80 amagat. The parts of the loss factor which are proportional to the square and cube of the density depend respectively on T−3.08±0.05 and T−5.4±0.059. These results together with existing infrared results show that τ2 is nearly proportional to T−0.5 and the ratio τ2/τ3 is 0.91 at 296 K. An initial measurement is reported for collision induced absorption in H2. The results for all three gases have been compared to previously reported results in the low frequency region.

Collision Induced Microwave Absorption in N2, CH4, and N2–Ar, N2–CH4 Mixtures at 1.1 and 2.3 cm−1

1974 ◽  
Vol 52 (9) ◽  
pp. 821-829 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
J. L. Urbaniak
Keyword(s):  
Microwave Absorption ◽  
Quadrupole Moment ◽  
Linear Dependence ◽  
Relaxation Times ◽  
High Sensitivity ◽  
Higher Order ◽  
Induced Absorption ◽  
High Q ◽  
Order Dependence

Collision induced microwave absorption is reported in pure N2, N2–Ar, N2–CH4, mixtures, and in pure CH4 in the 35 and 70 GHz regions (1.1 and 2.3 cm−1) at a temperature of 22 °C. The measurements are accomplished using overmoded high Q cavities capable of pressurization of up to 5000 p.s.i.g. The apparatus and method are described. With the high sensitivity attained, the results in pure N2 from 30 → 250 amagat reveal terms in the square and cube of the density from which the relaxation times are calculated. The linear dependence on frequency of the collision induced absorption up to 2.3 cm−1 is established. Higher order dependence on the density is observed in the N2–Ar and N2–CH4 mixtures. Various estimates of the quadrupole moment of N2 are given, making use of earlier results in other frequency regions.

Determination of polarization relaxation times of atomic levels

2012 ◽  
Vol 47 (5) ◽  
pp. 222-224 ◽  
Author(s):  
G. G. Adonts ◽  
E. G. Kanetsyan ◽  
M. A. Arzakantsyan
Keyword(s):  
Relaxation Times

Dynamical Evolution of Globular Clusters with Mass Spectrum

1991 ◽  
Vol 9 (1) ◽  
pp. 41-44
Author(s):  
Hyung Mok Lee
Keyword(s):  
Mass Spectrum ◽  
Globular Clusters ◽  
Numerical Models ◽  
Relaxation Times ◽  
Dynamical Evolution ◽  
Planck Equation ◽  
Mass Function ◽  
Low Mass Stars ◽  
Wide Range ◽  
Three Body

AbstractWe present a series of numerical models describing the dynamical evolution of globular clusters with a mass spectrum, based on integration of the Fokker-Planck equation. We include three-body binary heating and a steady galactic tidal field. A wide range of initial mass functions is adopted and the evolution of the mass function is examined. The mass function begins to change appreciably during the post-collapse expansion phase due to the selective evaporation of low mass stars through the tidal boundary. One signature of highly evolved clusters is thus the significant flattening of the mass function. The age (in units of the half-mass relaxation time) increases very rapidly beyond about 100 signifying the final stage of cluster disruption. This appears to be consistent with the sharp cut-off of half-mass relaxation times at near 108 years for the Galactic globular clusters.

scholarly journals The Lunar orbit paradox

2013 ◽  
Vol 40 (1) ◽  
pp. 135-146
Author(s):  
Aleksandar Tomic
Keyword(s):  
Inertial Mass ◽  
Lunar Orbit ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
Three Body ◽  
Origin Of The Moon ◽  
Force Intensity ◽  
Critical Consideration

Newton's formula for gravity force gives greather force intensity for atraction of the Moon by the Sun than atraction by the Earth. However, central body in lunar (primary) orbit is the Earth. So appeared paradox which were ignored from competent specialist, because the most important problem, determination of lunar orbit, was inmediately solved sufficiently by mathematical ingeniosity - introducing the Sun as dominant body in the three body system by Delaunay, 1860. On this way the lunar orbit paradox were not canceled. Vujicic made a owerview of principles of mechanics in year 1998, in critical consideration. As an example for application of corrected procedure he was obtained gravity law in some different form, which gave possibility to cancel paradox of lunar orbit. The formula of Vujicic, with our small adaptation, content two type of acceleration - related to inertial mass and related to gravity mass. So appears carried information on the origin of the Moon, and paradox cancels.

scholarly journals Single-sided NMR for the measurement of the degree of cross-linking and curing

2018 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Norbert Halmen ◽  
Christoph Kugler ◽  
Eduard Kraus ◽  
Benjamin Baudrit ◽  
Thomas Hochrein ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Curing Kinetics ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
First Results ◽  
Non Destructive ◽  
Kinetics Of ◽  
Good Agreement

Abstract. The degree of cross-linking and curing is one of the most important values concerning the quality of cross-linked polyethylene (PE-X) and the functionality of adhesives and resin-based components. Up to now, the measurement of this property has mostly been time-consuming and usually destructive. Within the shown work the feasibility of single-sided nuclear magnetic resonance (NMR) for the non-destructive determination of the degree of cross-linking and curing as process monitoring was investigated. First results indicate the possibility of distinguishing between PE-X samples with different degrees of cross-linking. The homogeneity of the samples and the curing kinetics of adhesives can also be monitored. The measurements show good agreement with reference tests (wet chemical analysis, differential scanning calorimetry, dielectric analysis). Furthermore, the influence of sample temperature on the characteristic relaxation times can be observed.

Sign in / Sign up

Export Citation Format

Share Document