scholarly journals SELF-TRAPPING AT THE LIQUID-VAPOR CRITICAL POINT

2006 ◽  
Vol 20 (04) ◽  
pp. 169-177 ◽  
Author(s):  
BRUCE N. MILLER ◽  
TERRENCE L. REESE
Keyword(s):  
Critical Point ◽  
Scattering Length ◽  
Atom Scattering ◽  
Self Trapping ◽  
Atom Interaction ◽  
Low Mass ◽  
First Time ◽  
Positive Particle ◽  
Surrounding Fluid ◽  
Liquid Vapor

Experiments suggest that localization via self-trapping plays a central role in the behavior of equilibrated low mass particles in both liquids and in supercritical fluids. In the latter case, the behavior is dominated by the liquid-vapor critical point which is difficult to probe, both experimentally and theoretically. Here, for the first time, we present the results of path-integral computations of the characteristics of a self-trapped particle at the critical point of a Lennard-Jones fluid for a positive particle-atom scattering length. We investigate the influence of the range of the particle-atom interaction on trapping properties, and the pick-off decay rate for the case where the particle is ortho-positronium. We find that, at the critical point, the transition from the self-trapped inhomogeneity to the density of the surrounding fluid is more gradual than in the liquid, or dense gas, away from the critical point. In addition the "shell structure" in fluid density surrounding the droplet is effaced.

scholarly journals Visible AO Observations at Halpha for Accreting Young Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 32-33
Author(s):  
L.M. Close ◽  
K. Follette ◽  
J.R. Males ◽  
K. Morzinski ◽  
T.J. Rodigas ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Binary Stars ◽  
Optical Resolution ◽  
Ccd Camera ◽  
Short Exposure ◽  
Low Mass ◽  
Orion Trapezium ◽  
First Time ◽  
Adaptive Optics System ◽  
Very High

AbstractWe utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high-resolution science in the visible with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0.5–0.7″) we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60s) r' (0.63μm) images are slightly coarser at FWHM = 23-29 mas (Strehl ~ 28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young (~ 1 Myr) Orion Trapezium θ1 Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary θ1 Ori C1C2 was easily resolved in non-interferometric images for the first time. Relative positions of the bright trapezium binary stars were measured with ~ 0.6–5 mas accuracy. In the second commissioning run we were able to correct 378 modes and achieved good contrasts (Strehl>20% on young transition disks at Hα). We discuss the contrasts achieved at Hα and the possibility of detecting low mass (~ 1–5 Mjup) planets (past 5AU) with our new SAPPHIRES survey with MagAO at Hα.

scholarly journals GEM-Based Detectors for Direct Detection of Low-Mass WIMP, Solar Axions and Narrow Resonances (Quarks)

2021 ◽  
Author(s):  
Victor Parusov ◽  
Boris Ovchinnikov
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Beta Particle ◽  
Gaseous Mixtures ◽  
Low Mass ◽  
Nonzero Spin ◽  
Time Projection ◽  
First Time ◽  
Solar Axions ◽  
Low Mass Wimp

Gas electron multipliers (GEMs) with wire (WGEMs) or metal electrodes (MGEMs), which don&rsquo;t use any plastic insulators between electrodes are created. The chambers containing MGEMs (WGEMs) with pin-anodes are proposed as detectors for searching of spin-dependent interactions between Dark Matter (DM) particles and gases with nonzero-spin nuclei (H2, D2, 3He, 21Ne, CF4, CH4, etc.). In this paper, we present a review of such chambers. For investigation of the gas mixtures Ne+10%H2, H2 (D2) +3ppmTMAE, the chamber containing WGEM with pin-anode detection system was constructed. In this paper we present the results of an experimental study of these gaseous mixtures exited by an &alpha; - source. Mixture of Ar + 40 ppm C2H4 and mixture 50% Xe + 50%CF4 have been investigated. The spatial distributions of photoelectron clouds produced by primary scintillations on &alpha;- and &beta;-particle tracks, as well as the distributions of photoelectron clouds due to photons from avalanches at the pin-anode, have been measured for the first time. In our experiments as another filling of the chambers for search of low-mas WIMP (&lt;10 GeV/c2), solar neutrino and solar axions with spin-dependent interaction we propose to use the mixtures: D2 + 3ppmTMAE, 3He + 3%CH4, 21Ne + 10%H2, at pressure 10-17 bar. And in our experiment with liquid gases is used the mixtures with 19F (LAr + CF4, LXe + CF4) and mixture LCH4 + 40ppm TMAE. The time projection chamber (TPC) with the mixture D2 + 3ppmTMAE filling allow to search of spin-dependent interactions of solar axions and deuterium. As well as we present the detecting systems for search of narrow pp-resonances (quarks) in accelerators experiments.

Liquid-vapor critical point of physisorbed films

1984 ◽  
Vol 148 (1) ◽  
pp. 200-211 ◽  
Author(s):  
James R. Klein ◽  
M.H.W. Chan ◽  
Milton W. Cole
Keyword(s):  
Critical Point ◽  
Liquid Vapor

Liquid-vapor critical point of physisorbed films

1984 ◽  
Vol 148 (1) ◽  
pp. A484
Author(s):  
James R. Klein ◽  
M.H.W. Chan ◽  
Milton W. Cole
Keyword(s):  
Critical Point ◽  
Liquid Vapor

Transport properties of helium near the liquid-vapor critical point. IV. The shear viscosity of3He and4He

1987 ◽  
Vol 67 (3-4) ◽  
pp. 237-289 ◽  
Author(s):  
Charles C. Agosta ◽  
Suwen Wang ◽  
L. H. Cohen ◽  
H. Meyer
Keyword(s):  
Transport Properties ◽  
Critical Point ◽  
Shear Viscosity ◽  
Liquid Vapor

scholarly journals Be it therefore resolved: cosmological simulations of dwarf galaxies with 30 solar mass resolution

2019 ◽  
Vol 490 (3) ◽  
pp. 4447-4463 ◽  
Author(s):  
Coral Wheeler ◽  
Philip F Hopkins ◽  
Andrew B Pace ◽  
Shea Garrison-Kimmel ◽  
Michael Boylan-Kolchin ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Stellar Rotation ◽  
Solar Mass ◽  
Dynamical Mass ◽  
Low Mass ◽  
Star Formation Histories ◽  
First Time

ABSTRACT We study a suite of extremely high-resolution cosmological Feedback in Realistic Environments simulations of dwarf galaxies ($M_{\rm halo} \lesssim 10^{10}\rm \, M_{\odot }$), run to z = 0 with $30\, \mathrm{M}_{\odot }$ resolution, sufficient (for the first time) to resolve the internal structure of individual supernovae remnants within the cooling radius. Every halo with $M_{\rm halo} \gtrsim 10^{8.6}\, \mathrm{M}_{\odot }$ is populated by a resolved stellar galaxy, suggesting very low-mass dwarfs may be ubiquitous in the field. Our ultra-faint dwarfs (UFDs; $M_{\ast }\lt 10^{5}\, \mathrm{M}_{\odot }$) have their star formation (SF) truncated early (z ≳ 2), likely by reionization, while classical dwarfs ($M_{\ast }\gt 10^{5}\, \mathrm{M}_{\odot }$) continue forming stars to z &lt; 0.5. The systems have bursty star formation histories, forming most of their stars in periods of elevated SF strongly clustered in both space and time. This allows our dwarf with M*/Mhalo &gt; 10−4 to form a dark matter core ${\gt}200\rm \, pc$, while lower mass UFDs exhibit cusps down to ${\lesssim}100\rm \, pc$, as expected from energetic arguments. Our dwarfs with $M_{\ast }\gt 10^{4}\, \mathrm{M}_{\odot }$ have half-mass radii (R1/2) in agreement with Local Group (LG) dwarfs (dynamical mass versus R1/2 and stellar rotation also resemble observations). The lowest mass UFDs are below surface brightness limits of current surveys but are potentially visible in next-generation surveys (e.g. LSST). The stellar metallicities are lower than in LG dwarfs; this may reflect pre-enrichment of the LG by the massive hosts or Pop-III stars. Consistency with lower resolution studies implies that our simulations are numerically robust (for a given physical model).

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