10,238 research outputs found
Identifications and SEDs of the detected sources from the AKARI Deep Field South
In order to find counterparts of the detected objects in the AKARI Deep Field
South (ADFS) in all available wavelengths, we searched public databases (NED,
SIMBAD and others). Checking 500 sources brighter than 0.0482 Jy in the AKARI
Wide-S band, we found 114 sources with possible counterparts, among which 78
were known galaxies. We present these sources as well as our first attempt to
construct spectral energy distributions (SEDs) for the most secure and most
interesting sources among them, taking into account all the known data together
with the AKARI measurements in four bands.Comment: 4 pages, 10 figures, To appear in: the proceedings of the conference
"AKARI, a light to illuminate the misty Universe", February 16-19 2009, Toky
Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements
Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh
Ecology of helminthes parasites of Capoeta capoeta gracilis from Shiroud River, Iran
In the present study 959 specimens of Capoeta capoeta gracilis were studied for their helminth parasites in two sampling areas in Shiroud River. Samplings were carried out during one year from January 2002 to January 2003. Nine species of parasites were identified namely: Clinostomum complanatum, Diplostomum spathaceum, Posthodiplostomum cuticola, Allocreadium sp. (trematoda), Dactylogyrus pulcher, Dactylogyrus lenkorani, Gyrodoctylus mutabilitas (Monogenea) Rhabdochona fortunatowi, Capilaria sp. (Nematoda). The Capillaria sp. was found only in one sampling area. There are significant differences between the abundance and prevalence of Rhabdochona fortunatowi, P. cuticola, C complanatus, D. spathaceum, Allocreadium sp. In two study areas, prevalence, abundance, species richness, diversity equitability and similarity indices were compared between two study areas and the significant differences are discussed
Minimization of Threshold-Current Dependence of Quantum Dot Laser Using InN
This paper focuses on the effect of threshold current density on different characteristics of quantum dot based laser. To investigate the effect, different characteristics have been analyzed using quantum dot as the active layer material of the laser structure. Performance improvement of quantum dot laser using InN has been achieved in terms of minimization of the threshold current dependence such as mirror loss, modal gain, turn-on delay and so forth. Numerical results have been analyzed considering the values of threshold current densities of GaN, AlN and InN based quantum dot lasers. Analytical results show that internal loss increases linearly with the increase of the threshold current density. However, other characteristics like mirror loss, modal gain, turn-on delay have nonlinear dependence on the threshold current density for any material used in the active layer. The threshold current density of InN quantum dot based laser is lower than that of other existing quantum dot based lasers. Analytical results ascertained that mirror loss has been increased a little bit. Conversely, internal loss and modal gain have been minimized considerably using InN based quantum dot in the active layer of the laser structure. In addition, turn-on delay time has been also minimized significantly
Dusty Universe viewed by AKARI far infrared detector
We present the results of the analysis of multiwavelength Spectral Energy
Distributions (SEDs) of far-infrared galaxies detected in the AKARI Deep
Field-South (ADF--S) Survey. The analysis uses a carefully selected sample of
186 sources detected at the 90 m AKARI band, identified as galaxies with
cross-identification in public catalogues. For sources without known
spectroscopic redshifts, we estimate photometric redshifts after a test of two
independent methods: one based on using mainly the optical -- mid infrared
range, and one based on the whole range of ultraviolet -- far infrared data. We
observe a vast improvement in the estimation of photometric redshifts when far
infrared data are included, compared with an approach based mainly on the
optical -- mid infrared range. We discuss the physical properties of our
far-infrared-selected sample. We conclude that this sample consists mostly of
rich in dust and young stars nearby galaxies, and, furthermore, that almost 25%
of these sources are (Ultra)Luminous Infrared Galaxies. Average SEDs normalized
at 90 m for normal galaxies (138 sources), LIRGs (30 sources), and ULIRGs
(18 galaxies) a the significant shift in the peak wavelength of the dust
emission, and an increasing ratio between their bolometric and dust
luminosities which varies from 0.39 to 0.73.Comment: 8 pages, 7 figures, published in Earth, Planets and Spac
"Swarm relaxation": Equilibrating a large ensemble of computer simulations
It is common practice in molecular dynamics and Monte Carlo computer
simulations to run multiple, separately-initialized simulations in order to
improve the sampling of independent microstates. Here we examine the utility of
an extreme case of this strategy, in which we run a large ensemble of
independent simulations (a "swarm"), each of which is relaxed to equilibrium.
We show that if is of order , we can monitor the swarm's relaxation
to equilibrium, and confirm its attainment, within , where
is the equilibrium relaxation time. As soon as a swarm of this size
attains equilibrium, the ensemble of final microstates from each run is
sufficient for the evaluation of most equilibrium properties without further
sampling. This approach dramatically reduces the wall-clock time required,
compared to a single long simulation, by a factor of several hundred, at the
cost of an increase in the total computational effort by a small factor. It is
also well-suited to modern computing systems having thousands of processors,
and is a viable strategy for simulation studies that need to produce
high-precision results in a minimum of wall-clock time. We present results
obtained by applying this approach to several test cases.Comment: 12 pages. To appear in Eur. Phy. J. E, 201
Doping and band-gap engineering of an intrazeolite tungsten(VI) oxide supralattice
New results are presented concerning the topotactic self-assembly, n-type
doping and band-gap engineering of an intrazeolite tungsten(VI) oxide supralattice
n(W03)-Na56Y, where 0 < η < 32, built-up of single size and shape (W03)2
dimers. In particular it has been found that the oxygen content of these dimers
can be quantitatively adjusted by means of a thermal vacuum induced reversible
reductive-elimination oxidative-addition of dioxygen. This provides access to new
n(W03.x)-Na56Y materials (0 < χ ^ 1.0) in which the oxygen content, structural
properties and electronic architecture of the dimers are changed. In this way one
can precisely control the oxidation state, degree of η-doping and band-filling of a
tungsten(VI) oxide supralattice through an approach which can be considered akin
to, but distinct in detail to, that found in the Magneli crystallographic shear phases
of non-stoichiometric bulk W03.x . Another discovery concerns the ability to alter
local electrostatic fields experienced by the tungsten(VI) oxide moieties housed in
the 13Ä supercages of 16(W03)-M36Y, by varying the ionic potential of the
constituent supercage M + cations across the alkali metal series. This method
provides the first opportunity to fine-tune the band-gap of a tungsten(VI) oxide
supralattice. Α miniband electronic description is advanced as a qualitative first
attempt to understand the origin of the above effects. The implications of these
discoveries are that cluster size, composition and intrinsic electrostatic field effects
can be used to "chemically manipulate" (engineer) the doping and band
architecture of intrazeolite supralattices of possible interest in quantum electronics
and nonlinear optics
A novel green antenna phase-shift system with data acquisition boards
A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦
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