1,174,206 research outputs found
Optimum satellite orbits for accurate measurement of the earth's radiation budget, summary
The optimum set of orbit inclinations for the measurement of the earth radiation budget from spacially integrating sensor systems was estimated for two and three satellite systems. The best set of the two were satellites at orbit inclinations of 80 deg and 50 deg; of three the inclinations were 80 deg, 60 deg and 50 deg. These were chosen on the basis of a simulation of flat plate and spherical detectors flying over a daily varying earth radiation field as measured by the Nimbus 3 medium resolution scanners. A diurnal oscillation was also included in the emitted flux and albedo to give a source field as realistic as possible. Twenty three satellites with different inclinations and equator crossings were simulated, allowing the results of thousand of multisatellite sets to be intercompared. All were circular orbits of radius 7178 kilometers
A q-analogue of convolution on the line
In this paper we study a q-analogue of the convolution product on the line in
detail. A convolution product on the braided line was defined algebraically by
Kempf and Majid. We adapt their definition in order to give an analytic
definition for the q-convolution and we study convergence extensively. Since
the braided line is commutative as an algebra, all results can be viewed both
as results in classical q-analysis and in braided algebra. We define various
classes of functions on which the convolution is well-defined and we show that
they are algebras under the defined product. One particularly nice family of
algebras, a decreasing chain depending on a parameter running through (0,1],
turns out to have 1/2 as the critical parameter value above which the algebras
are commutative. Morerover, the commutative algebras in this family are
precisely the algebras in which each function is determined by its q-moments.
We also treat the relationship between q-convolution and q-Fourier transform.
Finally, in the Appendix, we show an equivalence between the existence of an
analytic continuation of a function defined on a q-lattice, and the behaviour
of its q-derivatives.Comment: 31 pages; many small corrections; accepted by Methods and
Applications of Analysi
X-Ray Evidence of an AGN in M82
An X-ray spectrum of the famous starburst galaxy M82 consists of three
components: soft, medium, and hard components (Tsuru et al. 1997). The spectrum
of the hard component, which is spatially unresolved, is well represented by an
absorbed thermal bremsstrahlung, or an absorbed power-law model. However the
origin of the hard component was unclear. Thus, we made a monitoring
observation with ASCA in 1996. Although the X-ray flux of the soft and medium
components remained constant, a significant time variability of the hard
component was found between erg/s and erg/s
at various time scales from 10 ks to a month. The temperature or photon index
of the hard component also changed. We proved that the spatial position of the
hard component is the center of M82. The spectrum of the variable source
obtained by subtracting the spectrum of the lowest state from the highest state
suggests the strong absorption of cm, which means
the variable source is embedded in the center of M82. All these suggest that a
low-luminosity AGN exists in M82.Comment: 15pages for text and tables. 13pages for figure
Superfluid response in electron-doped cuprate superconductors
We propose a weakly coupled two-band model with pairing
symmetry to account for the anomalous temperature dependence of superfluid
density in electron-doped cuprate superconductors. This model gives a
unified explanation to the presence of a upward curvature in near
and a weak temperature dependence of in low temperatures. Our
work resolves a discrepancy in the interpretation of different experimental
measurements and suggests that the pairing in electron-doped cuprates has
predominately symmetry in the whole doping range.Comment: 4 pages, 3 figures, title changed and references adde
Comment on "Potential Energy Landscape for Hot Electrons in Periodically Nanostructured Graphene"
In a recent letter [Phys. Rev. Lett. 105 (2010) 036804] the unoccupied
electronic states of single layers of graphene on ruthenium are investigated.
Here we comment on the interpretation, which deviates in four points from [J.
Phys.: Condens. Matter 22 (2010) 302001] and outline the corresponding
consequences
Andreev Edge State on Semi-Infinite Triangular Lattice: Detecting the Pairing Symmetry in Na_0.35CoO_2.yH_2O
We study the Andreev edge state on the semi-infinite triangular lattice with
different pairing symmetries and boundary topologies. We find a rich phase
diagram of zero energy Andreev edge states that is a unique fingerprint of each
of the possible pairing symmetries. We propose to pin down the pairing symmetry
in recently discovered Na_xCoO_2 material by the Fourier-transformed scanning
tunneling spectroscopy for the edge state. A surprisingly rich phase diagram is
found and explained by a general gauge argument and mapping to 1D tight-binding
model. Extensions of this work are discussed at the end.Comment: 4 pages, 1 table, 4 figure
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