14,735 research outputs found
Japanese activities in refrigeration technology
Recent activities in refrigeration technology in Japan are discussed. Stirling cycle refrigerators and magnetic refrigerators are discussed. The development of units for use on trains is discussed
Unique representation d=4k(k^2-1) in D(4)-quadruples {k-2,k+2,4k,d}
Let k ≥ 3 be an integer. We show that if d is a positive integer such that the product of any two distinct elements of the set
{k-2,k+2,4k,d} increased by 4 is a square, then d must be
4k(k^2-1)
The Variation of Gas Mass Distribution in Galaxy Clusters: Effects of Preheating and Shocks
We investigate the origin of the variation of the gas mass fraction in the
core of galaxy clusters, which was indicated by our work on the X-ray
fundamental plane. The adopted model supposes that the gas distribution
characterized by the slope parameter is related to the preheated temperature.
Comparison with observations of relatively hot (~> 3 keV) and low redshift
clusters suggests that the preheated temperature is about 0.5-2 keV, which is
higher than expected from the conventional galactic wind model and possibly
suggests the need for additional heating such as quasars or gravitational
heating on the largest scales at high redshift. The dispersion of the preheated
temperature may be attributed to the gravitational heating in subclusters. We
calculate the central gas fraction of a cluster from the gas distribution,
assuming that the global gas mass fraction is constant within a virial radius
at the time of the cluster collapse. We find that the central gas density thus
calculated is in good agreement with the observed one, which suggests that the
variation of gas mass fraction in cluster cores appears to be explained by
breaking the self-similarity in clusters due to preheated gas. We also find
that this model does not change major conclusions on the fundamental plane and
its cosmological implications obtained in previous papers, which strongly
suggests that not only for the dark halo but also for the intracluster gas the
core structure preserves information about the cluster formation.Comment: 17 pages, to be published in Ap
Time-dependent, species-specific effects of N:P stoichiometry on grassland plant growth
N and P have different eutrophication effects on grassland communities, yet the underlying mechanisms are poorly understood. To examine plant growth in response to the varying (relative) supply of N and P, we conducted a two-year greenhouse experiment. Five grasses and three herbs were grown with three N:P supply ratios at two overall nutrient supply levels. During the first year the plant growth was relatively low at both high and low N:P supply ratios, whereas during the second year the growth was especially low at a high N:P supply ratio. This second-year low growth was attributed to the high root death rate, which was influenced by a high N:P supply ratio rather than by the nutrient supply level. Species responded differently, especially in P uptake and loss at a high N:P supply ratio. Each species seemed to have a different strategy for P limitation, e.g. an efficient P uptake or a high P resorption rate. Species typical of P-limited grasslands had neither better P uptake nor better P retention at a high N:P supply ratio. This study quantitatively demonstrates an increased plant root death triggered by strong P limitation. This finding indicates a possible extra effect of N eutrophication on ecosystem functioning via changed N:P stoichiometr
Klinische Untersuchungen über die Resorptionskraft aus dem Subcutis
Nach Donath u. Tanne haben wir die Resorptionszeit des Uranins aus dem Subcutis bei verschiedenartigen Kranken untersucht. Unter den Resultaten sind die folgenden hervorzuheben; bei Morbus Basedowi, Kreislaufinsuffizienzien, hydropischen Nephritiden, Beriberi, Leberkrankheiten, Pleuritiden, bes. bei frischen Fällen und schweren Tuberkulosen wurde die Resorption mehr oder weniger erheblich verlangsamt. Bei Ankylostomiaden war sie bald unverändert, bald eher verlangsamt, bes. verlangsamt bei denen mit hochgradiger Anämie. Bei Pleuritiden war es verschieden je nach den Krankheitsstadien, da sie z. B. bei frischen, zur Exsudation neigenden Fällen verlangsam war, während sie mit der Krankheitsbesserung zusammen immer schneller wurde und bei veralteten, mit Schwartenbildung oder mit immer gröber werdenden Reiben behafteten Fällen sogar fast normal war.
Für den Ausfall dieser Probe spielt nicht nur der Zustand des Kreislaufes, wie die Blutströmungsgeschwindigkeit und die Blutdruckamplitude etc, wie Donath u. Tanne annahm, eine gewisse Rolle, sondern auch der Gewebszustand, dieser sogar eher grössere Rolle
Synchrotron X-ray diffraction study of a charge stripe order in 1/8-doped LaBaSrCuO
Lattice distortions associated with charge stripe order in 1/8 hole-doped
LaBaSrCuO are studied using synchrotron X-ray
diffraction for and . The propagation wave vector and charge
order correlation lengths are determined with a high accuracy, revealing that
the oblique charge stripes in orthorhombic crystal are more
disordered than the aligned stripes in tetragonal crystal. The twofold
periodicity of lattice modulations along the c-axis is explained by long-range
Coulomb interactions between holes on neighboring CuO planes.Comment: 4pages, 4figures, Submitted to PR
Environmental effects on star formation in dwarf galaxies and star clusters
We develop a simple analytical criterion to investigate the role of the
environment on the onset of star formation. We will consider the main external
agents that influence the star formation (i.e. ram pressure, tidal interaction,
Rayleigh-Taylor and Kelvin-Helmholtz instabilities) in a spherical galaxy
moving through an external environment. The theoretical framework developed
here has direct applications to the cases of dwarf galaxies in galaxy clusters
and dwarf galaxies orbiting our Milky Way system, as well as any primordial
gas-rich cluster of stars orbiting within its host galaxy. We develop an
analytic formalism to solve the fluid dynamics equations in a non-inertial
reference frame mapped with spherical coordinates. The two-fluids instability
at the interface between a stellar system and its surrounding hotter and less
dense environment is related to the star formation processes through a set of
differential equations. The solution presented here is quite general, allowing
us to investigate most kinds of orbits allowed in a gravitationally bound
system of stars in interaction with a major massive companion. We present an
analytical criterion to elucidate the dependence of star formation in a
spherical stellar system (as a dwarf galaxy or a globular cluster) on its
surrounding environment useful in theoretical interpretations of numerical
results as well as observational applications. We show how spherical
coordinates naturally enlighten the interpretation of the two-fluids
instability in a geometry that directly applies to astrophysical case. This
criterion predicts the threshold value for the onset of star formation in a
mass vs. size space for any orbit of interest. Moreover, we show for the first
time the theoretical dependencies of the different instability phenomena acting
on a system in a fully analytical way.Comment: ACCEPTED in A&A the 09/09/2014. Changes from ver 1: the non-inertial
linear-response theory for gas instabilities in spherical coordinates is
moved to the Appenidx and will be available only on-lin
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