Density dependence of the Hanle effect of the 4s4p1P1 level of neutral calcium

1980 ◽  
Vol 58 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
High Density ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
High Density Region

The Hanle effect in the 4s21S0–4s4p1P1 (4226.7 Å) transition in Ca I has been observed over a wide range of densities. The low density observations determine the lifetime of the 1P1 level to be 4.49 ns. Collision parameters are obtained from observations in the high density region.

Monte Carlo and Perturbation Calculations for a Triangular Well Fluid

1974 ◽  
Vol 52 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Damon N. Card ◽  
John Walkley
Keyword(s):  
Monte Carlo ◽  
Hard Spheres ◽  
Low Density ◽  
Monte Carlo Data ◽  
Density Region ◽  
Wide Range ◽  
Model Fluid ◽  
High Density Region ◽  
Superposition Approximation ◽  
Triangular Well Potential

Monte Carlo data have been generated for a simple model fluid consisting of hard spheres with an attractive triangular well potential. The ranges spanned by the temperature and density are as follows. [Formula: see text] and [Formula: see text]. The machine data have been compared to the modern perturbation theories of (i) Barker, Henderson, and Smith and (ii) Weeks, Chandler, and Andersen. Comparison with the machine data shows that the latter theory is successful in the high density region only, but over a wide range of temperature. The Barker–Henderson approach is best in the low density region but the use of the superposition approximation limits the utility of this theory at high densities.

The density dependence of the Hanle effect in the resonance line of atomic barium

1977 ◽  
Vol 55 (1) ◽  
pp. 83-91 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Cross Sections ◽  
Resonance Line ◽  
Excited Level ◽  
Ground Level ◽  
Multipole Moment ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
Theoretical Predictions

The change in the Hanle effect of the singlet resonance line of neutral barium has been studied over a wide range of density. The low density region has been used to confirm a lifetime of 8.37 ± 0.08 ns for the 6s6p1P1 level. We have determined the cross sections for the relaxation of the multipole moment of order 2 for collisions of the excited level with the ground level and with the metastable 6s5d1D2 level, and comparisons are made with the measured value of [Formula: see text] for the ground level with theoretical predictions.

Density dependence of the Hanle effect of the 3s4p1P10 level of neutral magnesium

1979 ◽  
Vol 57 (6) ◽  
pp. 838-840
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
Excited Level ◽  
Lifetime Measurement ◽  
Oscillator Strengths ◽  
Low Density ◽  
Hanle Effect

The Hanle effect in the 3s2 1S0–3s4p1P1 (2026 Å) transition of Mg I has been studied over a range of densities. The low density observations lead to an accurate lifetime measurement of the 4p1P1 excited level. Related oscillator strengths are calculated.

Stimulated Brillouin scattering behaviors in multi-ion species plasmas in high-temperature and high-density region

2019 ◽  
Vol 26 (5) ◽  
pp. 052101 ◽  
Author(s):  
Q. S. Feng ◽  
C. Y. Zheng ◽  
Z. J. Liu ◽  
L. H. Cao ◽  
Q. Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
High Density ◽  
Density Region ◽  
High Density Region ◽  
Stimulated Brillouin ◽  
Ion Species

scholarly journals Early Shaping of Asymmetric Planetary Nebulae

1989 ◽  
Vol 106 ◽  
pp. 232-232
Author(s):  
Noam Soker
Keyword(s):  
Planetary Nebula ◽  
Binary Star ◽  
Symmetry Plane ◽  
Planetary Nebulae ◽  
High Density ◽  
Close Binary ◽  
Density Region ◽  
Short Period ◽  
Fast Wind ◽  
High Density Region

We suggest that the shape of a young asymmetric planetary nebulae may be influenced by a close binary star located at its center. This binary is a relic of the common envelope phase, presumably through which the asymmetric planetary nebula evolved. We assume that for a short period of time, shortly after the cession of the slow wind and long before the fast wind becomes effective, the binary ejects a small amount of mass, mainly in the equatorial plane. In this work we do not discuss the exact mechanism for the ejection of this pulse of mass. In the case in which the cooling is very efficient, (i.e., high-Mach-number isothermal flow), we can solve the problem analytically by using a few simplifying assumptions. In this case the high density region is shaped like a ring. We use two-dimensional hydrodynamics for the more general case. We find that at late times the high density region has a “horseshoe” shape, as viewed in the symmetry plane. There is an instability in the maximum density region. Finally we compare our results with the shape of the planetary nebula M2-9.

TRAFFIC FLOW ON A 3-LANE HIGHWAY

2004 ◽  
Vol 18 (31n32) ◽  
pp. 4161-4171 ◽  
Author(s):  
WEN-YAO CHEN ◽  
DING-WEI HUANG ◽  
WEI-NENG HUANG ◽  
WEN-LIANG HWANG
Keyword(s):  
Cellular Automaton ◽  
Traffic Flow ◽  
Low Density ◽  
Density Region ◽  
Lane Changing ◽  
Driving Behaviors ◽  
Control Scheme ◽  
High Density Region ◽  
Cellular Automaton Method ◽  
Changing Rate

The traffic flow on a 3-lane highway is investigated using a cellular automaton method. Two different kinds of vehicles, cars and trucks, with different driving behaviors are presented on the highway. It is found that in the high density region, a control scheme requiring passing from the inner lane will enhance the traffic flow; while restricting the trucks to the outer lane will enhance the flow in the low density region and also has the benefit of suppressing the unnecessary lane-changing rate.

Visualization of the stop of microtubule depolymerization that occurs at the high-density region of microtubule-associated protein 2 (MAP2) 1 1Edited by J. Karn

2001 ◽  
Vol 312 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Koji Ichihara ◽  
Hidefumi Kitazawa ◽  
Yusuke Iguchi ◽  
Hirokazu Hotani ◽  
Tomohiko J. Itoh
Keyword(s):  
High Density ◽  
Microtubule Depolymerization ◽  
Density Region ◽  
High Density Region

An experimental study on foaming of linear low-density polyethylene/high-density polyethylene blends

2016 ◽  
Vol 53 (1) ◽  
pp. 83-105 ◽  
Author(s):  
Peyman Shahi ◽  
Amir Hossein Behravesh ◽  
Ali Haghtalab ◽  
Ghaus Rizvi ◽  
Fatemeh Goharpei
Keyword(s):  
Bulk Density ◽  
High Density Polyethylene ◽  
Cell Structure ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Polyethylene Blends ◽  
Wide Range ◽  
Foaming Behavior

In this research work, foaming behavior of selected polyethylene blends was studied in a solid-state batch process, using CO2 as the blowing agent. Special emphasis was paid towards finding a relationship between foamability and thermal and rheological properties of blends. Pure high-density polyethylene, linear low-density polyethylene, and their blends with two weight fraction levels of high-density polyethylene (10 and 25%wt.) were examined. The dry blended batches were mixed using an internal mixer in a molten state, and then the disk-shaped specimens, 1.8 mm in thickness, were produced for foaming purposes. The foaming step was conducted over a wide range of temperatures (120–170℃), and the overall expansion and cellular morphology were evaluated via density measurements and captured SEM micrographs, respectively. Three-dimensional structural images were also captured using a high resolution X-ray micro CT for different foamed samples and were compared. Rheological and DSC tests for the virgin and blends were also performed to seek for a possible correlation with the formability. Based on the results, blended polyethylene foams exhibited remarkable expansion and highly enhanced cell structure compared to pure polymers. Bulk density, as low as 0.33 g/cm3, was obtained for blends, while for the virgin high-density polyethylene  and linear low-density polyethylene, bulk density lower than 0.5 g/cm3 was not attainable. The lowest density was observed at a foaming temperature of 10–20℃ above the melting (peak) temperature obtained via DSC test. Rheological characteristics, including storage modulus and cross-over frequency value, were also found to be the indicators for the materials foaming behavior. Moreover, blends with 25% wt. of high-density polyethylene exhibited the highest expansion values over a wider range of temperature compared with 90% linear low-density polyethylene/10% high-density polyethylene.

Gettering Effect in Low and High Density Structural Defect Regions of the Cast Multi-Crystalline-Silicon Wafer

2007 ◽  
Vol 994 ◽  
Author(s):  
Yongkook Park ◽  
Jinggang Lu ◽  
G. A. Rozgonyi
Keyword(s):  
Solar Cell ◽  
Structural Defect ◽  
Crystalline Silicon ◽  
High Density ◽  
Low Density ◽  
Density Region ◽  
Recombination Lifetime ◽  
Cell Processing ◽  
Defect Sites ◽  
Before And After

AbstractTwo cast multi-crystalline silicon (mc-Si) sister wafers before and after solar cell processing were investigated to explore the gettering effect in low and high density structural defect regions. For the processed wafer, the minority carrier recombination lifetime was correlated to the structural defect distribution. For the low density region of as-grown wafer, Cr impurities were 3.28x1013cm-3 and they were reduced to 1.74×1012cm−3 for the processed wafer. The isolated Cr impurities dissolved from the precipitates at 900°C which is the typical gettering temperature in the solar cell processing are getterd effectively in the low density regions. Our current understanding for the gettering effect in the high density regions is that the segregated Cr impurities at defect sites are not released to the silicon matrix at 900°C resulting in the poor gettering effect.

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