1,466 research outputs found
Dark filaments observed at 8.3mm and 3.1mm wavelength
Mapping of the sun was made at 3.1mm (98 GHz) and 8.3mm (36 GHz) wavelengths with a 45m dish radio telescope at the Nobeyama Cosmic Radio Observatory. The depressions associated with large H alpha filaments are derived to be -0.2 at 8.3mm and -0.05 at 3.1mm, which are darker than the values inferred by Raoult et al. (1979
Core excitation in Ozone localized to one of two symmetry-equivalent chemical bonds - molecular alignment through vibronic coupling
Core excitation from terminal oxygen O in O is shown to be an
excitation from a localized core orbital to a localized valence orbital. The
valence orbital is localized to one of the two equivalent chemical bonds. We
experimentally demonstrate this with the Auger Doppler effect which is
observable when O is core-excited to the highly dissociative
O1s7a state. Auger electrons emitted from the atomic oxygen
fragment carry information about the molecular orientation relative to the
electromagnetic field vector at the moment of excitation. The data together
with analytical functions for the electron-peak profiles give clear evidence
that the preferred molecular orientation for excitation only depends on the
orientation of one bond, not on the total molecular orientation. The
localization of the valence orbital "7a" is caused by mixing of the valence
orbital "5b" through vibronic coupling of anti-symmetric stretching mode
with b-symmetry. To the best of our knowledge, it is the first discussion
of the localization of a core excitation of O. This result explains the
success of the widely used assumption of localized core excitation in
adsorbates and large molecules
Single-crystal growth of underdoped Bi-2223
To investigate the origin of the enhanced Tc ({\approx} 110 K) of the
trilayer cuprate superconductor Bi2Sr2Ca2Cu3O10+{\delta} (Bi-2223), its
underdoped single crystals are a critical requirement. Here, we demonstrate the
first successful in-plane resistivity measurements of heavily underdoped
Bi-2223 (zero-resistivity temperatures {\approx} 20~35 K). Detailed crystal
growth methods, the annealing process, as well as X-ray diffraction (XRD) and
magnetic susceptibility measurement results are also reported.Comment: 4 pages, 4 figures, 27th International Symposium on
Superconductivity, ISS 2014, to appear in Physics Procedi
On the Light Curve and Spectrum of SN 2003dh Separated from the Optical Afterglow of GRB 030329
The net optical light curves and spectra of the supernova (SN) 2003dh are
obtained from the published spectra of GRB 030329, covering about 6 days before
SN maximum to about 60 days after. The bulk of the U-band flux is subtracted
from the observed spectra using early-time afterglow templates, because strong
line blanketing greatly depresses the UV and U-band SN flux in a metal-rich,
fast-moving SN atmosphere. The blue-end spectra of the gamma-ray burst
(GRB)connected hypernova SN 1998bw is used to determine the amount of
subtraction. The subtraction of a host galaxy template affects the late-time
results. The derived SN 2003dh light curves are narrower than those of SN
1998bw, rising as fast before maximum, reaching a possibly fainter maximum, and
then declining ~ 1.2-1.4 times faster. We then build UVOIR bolometric SN light
curve. Allowing for uncertainties, it can be reproduced with a spherical ejecta
model of Mej ~ 7+/-3 Msun, KE ~ (3.5+/-1.5)E52 ergs, with KE/Mej ~ 5 following
previous spectrum modelling, and M(Ni56) ~ (0.4 +0.15/-0.1) Msun. This suggests
a progenitor main-sequence mass of about 25-40 Msun, lower than SN 1998bw but
significantly higher than normal Type Ic SNe and the GRB-unrelated hypernova SN
2002ap.Comment: 18 pages, 7 figures, published by Ap
Radio Spectral Evolution of an X-ray Poor Impulsive Solar Flare: Implications for Plasma Heating and Electron Acceleration
We present radio and X-ray observations of an impulsive solar flare that was
moderately intense in microwaves, yet showed very meager EUV and X-ray
emission. The flare occurred on 2001 Oct 24 and was well-observed at radio
wavelengths by the Nobeyama Radioheliograph (NoRH), the Nobeyama Radio
Polarimeters (NoRP), and by the Owens Valley Solar Array (OVSA). It was also
observed in EUV and X-ray wavelength bands by the TRACE, GOES, and Yohkoh
satellites. We find that the impulsive onset of the radio emission is
progressively delayed with increasing frequency relative to the onset of hard
X-ray emission. In contrast, the time of flux density maximum is progressively
delayed with decreasing frequency. The decay phase is independent of radio
frequency. The simple source morphology and the excellent spectral coverage at
radio wavelengths allowed us to employ a nonlinear chi-squared minimization
scheme to fit the time series of radio spectra to a source model that accounts
for the observed radio emission in terms of gyrosynchrotron radiation from
MeV-energy electrons in a relatively dense thermal plasma. We discuss plasma
heating and electron acceleration in view of the parametric trends implied by
the model fitting. We suggest that stochastic acceleration likely plays a role
in accelerating the radio-emitting electrons.Comment: 22 pages, 10 figure
NASDA knowledge-based network planning system
One of the SODS (space operation and data system) sub-systems, NP (network planning) was the first expert system used by NASDA (national space development agency of Japan) for tracking and control of satellite. The major responsibilities of the NP system are: first, the allocation of network and satellite control resources and, second, the generation of the network operation plan data (NOP) used in automated control of the stations and control center facilities. Up to now, the first task of network resource scheduling was done by network operators. NP system automatically generates schedules using its knowledge base, which contains information on satellite orbits, station availability, which computer is dedicated to which satellite, and how many stations must be available for a particular satellite pass or a certain time period. The NP system is introduced
Analysis of IgE turnover in non-sensitized and sensitized rats.
BACKGROUND: Although the levels of immunoglobulin E (IgE) in the circulating blood are often elevated in patients with allergic diseases, such levels cannot always be considered as pathognomonic signs of allergy. The induction of allergic reactions in the tissue was inferred to be related to the amount of IgE passing through the vascular wall. AIMS: We attempted to clarify which compartment, the intravascular or extravascular, plays an important role in the regulation of the turnover of rat IgE. METHODS: The level of DNP-specific rat IgE in the serum was estimated by IgE-capture enzyme-linked immunosorbent assay, and the turnover of IgE was analyzed from its pharmacokinetic parameters. RESULTS: The transfer rate constants from the central to tissue compartment (Kct) were larger than those from the tissue to central compartment (Ktc) irrespective of the sensitized state. The value of the distribution volume of the tissue compartment (Vt) was larger than that of the distribution volume of the central compartment (Vc) irrespective of the sensitized state. CONCLUSIONS: These Findings suggest that the short half-life of rat IgE in the circulation could be attributable to the distribution of IgE from the intravascular to the extravascular compartment
Seeing-Induced Errors in Solar Doppler Velocity Measurements
Imaging systems based on a narrow-band tunable filter are used to obtain
Doppler velocity maps of solar features. These velocity maps are created by
taking the difference between the blue- and red-wing intensity images of a
chosen spectral line. This method has the inherent assumption that these two
images are obtained under identical conditions. With the dynamical nature of
the solar features as well as the Earth's atmosphere, systematic errors can be
introduced in such measurements. In this paper, a quantitative estimate of the
errors introduced due to variable seeing conditions for ground-based
observations is simulated and compared with real observational data for
identifying their reliability. It is shown, under such conditions, that there
is a strong cross-talk from the total intensity to the velocity estimates.
These spurious velocities are larger in magnitude for the umbral regions
compared to the penumbra or quiet-sun regions surrounding the sunspots. The
variable seeing can induce spurious velocities up to about 1 km/s It is also
shown that adaptive optics, in general, helps in minimising this effect.Comment: 14 page
Propagating waves in polar coronal holes as seen by SUMER and EIS
To study the dynamics of coronal holes and the role of waves in the
acceleration of the solar wind, spectral observations were performed over polar
coronal hole regions with the SUMER spectrometer on SoHO and the EIS
spectrometer on Hinode. Using these observations, we aim to detect the presence
of propagating waves in the corona and to study their properties. The
observations analysed here consist of SUMER spectra of the Ne VIII 770 A line
(T = 0.6 MK) and EIS slot images in the Fe XII 195 A line (T = 1.3 MK). Using
the wavelet technique, we study line radiance oscillations at different heights
from the limb in the polar coronal hole regions. We detect the presence of long
period oscillations with periods of 10 to 30 min in polar coronal holes. The
oscillations have an amplitude of a few percent in radiance and are not
detectable in line-of-sight velocity. From the time distance maps we find
evidence for propagating velocities from 75 km/s (Ne VIII) to 125 km/s (Fe
XII). These velocities are subsonic and roughly in the same ratio as the
respective sound speeds. We interpret the observed propagating oscillations in
terms of slow magneto-acoustic waves. These waves can be important for the
acceleration of the fast solar wind.Comment: 5 pages, 7 figures Accepted as Astronomy and Astrophysics Lette
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