718 research outputs found
Jarzynski equality for the transitions between nonequilibrium steady states
Jarzynski equality [Phys. Rev. E {\bf 56}, 5018 (1997)] is found to be valid
with slight modefication for the transitions between nonequilibrium stationary
states, as well as the one between equilibrium states. Also numerical results
confirm its validity. Its relevance for nonequilibrium thermodynamics of the
operational formalism is discussed.Comment: 5 pages, 2 figures, revte
Attempts for Simultaneous Observation of Image and Elemental Component in a Pottery Sample using Neutrons
AbstractIn the pottery sample which is the replica of the archeological sample, we attempted to get simultaneously not only the image by neutron radiography but also the information about elemental components by prompt gamma-ray analysis (PGA) at the B-4 beam hole that is usually used for the neutron radiography facility in Kyoto University Research Reactor Institute. It was confirmed that qualitative analysis of elements in the pottery sample was successfully performed by PGA at the B-4 beam hole and that PGA is applicable to the large sample analysis for inhomogeneous bulk archeological samples in the future
Lithophile element characteristics of acapulcoite-lodranite.
第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日(金) 国立国語研究所 2階講
Investigation of Diffuse Hard X-ray Emission from the Massive Star-Forming Region NGC 6334
Chandra ACIS-I data of the molecular cloud and HII region complex NGC 6334
were analyzed. The hard X-ray clumps detected with ASCA (Sekimoto et al. 2000)
were resolved into 792 point sources. After removing the point sources, an
extended X-ray emission component was detected over a 5x9 pc2 region, with the
0.5-8 keV absorption-corrected luminosity of 2x10^33 erg/s. The contribution
from faint point sources to this extended emission was estimated as at most ~20
%, suggesting that most of the emission is diffuse in nature. The X-ray
spectrum of the diffuse emission was observed to vary from place to place. In
tenuous molecular cloud regions with hydrogen column density of 0.5~1x10^22
cm-2, the spectrum can be represented by a thermal plasma model with
temperatures of several keV. The spectrum in dense cloud cores exhibits harder
continuum, together with higher absorption more than ~3x10^22 cm-2. In some of
such highly obscured regions, the spectrum show extremely hard continua
equivalent to a photon index of ~1, and favor non-thermal interpretation. These
results are discussed in the context of thermal and non-thermal emissions, both
powered by fast stellar winds from embedded young early-type stars through
shock transitions.Comment: 43 pages, 14 figures, accepted for publication in ApJ, A full
resolution ot the paper can be found at
http://www.astro.isas.jaxa.jp/~ezoe/ngc6334/yezoe2005apj_chandra_ngc6334.pd
Molecular Chemical Engines: Pseudo-Static Processes and the Mechanism of Energy Transduction
We propose a simple theoretical model for a molecular chemical engine that
catalyzes a chemical reaction and converts the free energy released by the
reaction into mechanical work. Binding and unbinding processes of reactant and
product molecules to and from the engine are explicitly taken into account. The
work delivered by the engine is calculated analytically for infinitely slow
(``pseudo-static'') processes, which can be reversible (quasi-static) or
irreversible, controlled by an external agent. It is shown that the work larger
than the maximum value limited by the second law of thermodynamics can be
obtained in a single cycle of operation by chance, although the statistical
average of the work never exceeds this limit and the maximum work is delivered
if the process is reversible. The mechanism of the energy transductionis also
discussed.Comment: 8 pages, 3 figues, submitted to J. Phys. Soc. Jp
Steady State Thermodynamics of Langevin Systems
We study Langevin dynamics describing nonequilibirum steady states. Employing
the phenomenological framework of steady state thermodynamics constructed by
Oono and Paniconi [Prog. Theor. Phys. Suppl. {\bf130}, 29 (1998)], we find that
the extended form of the second law which they proposed holds for transitions
between steady states and that the Shannon entropy difference is related to the
excess heat produced in an infinitely slow operation. A generalized version of
the Jarzynski work relation plays an important role in our theory.Comment: 4 page
Atomic Carbon and CO Isotope Emission in the Vicinity of DR15
We present observations of the 3P1-3P0 fine structure transition of atomic
carbon [CI], the J=3-2 transition of CO, as well as of the J=1-0 transitions of
13CO and C18O toward DR15, an HII region associated with two mid-infrared dark
clouds (IRDCs). The 13CO and C18O J=1-0 emissions closely follow the dark
patches seen in optical wavelength, showing two self-gravitating molecular
cores with masses of 2000 Msun and 900 Msun, respectively, at the positions of
the catalogued IRDCs.
Our data show a rough spatial correlation between [CI] and 13CO J=1-0. Bright
[CI] emission occurs in relatively cold gas behind the molecular cores, neither
in highly excited gas traced by CO J=3-2 emission nor in HII region/molecular
cloud interface. These results are inconsistent with those predicted by
standard photodissociation region (PDR) models, suggesting an origin for
interstellar atomic carbon unrelated to photodissociation processes.Comment: 11 pages Latex, 6 figures, Accepted for publication in The
Astrophysical Journa
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