252 research outputs found
Chandra Observations of the Northeastern Rim of the Cygnus Loop
We present results from spatially resolved spectral analyses of the
northeastern (NE) rim of the Cygnus Loop supernova remnant (SNR) based on two
Chandra observations. One pointing includes northern outermost
abundance-enhanced regions discovered by recent Suzaku observations, while the
other pointing is located on regions with "normal" abundances in the NE rim of
the Cygnus Loop. The superior spatial resolving power of Chandra allows us to
reveal that the abundance-enhanced region is concentrated in an about
200"-thickness region behind the shock front. We confirm absolute metal
abundances (i.e., relative to H) as well as abundance ratios between metals are
consistent with those of the solar values within a factor of about 2. Also, we
find that the emission measure in the region gradually decreases toward the
shock front. These features are in contrast with those of the ejecta fragments
around the Vela SNR, which leads us to believe that the abundance enhancements
are not likely due to metal-rich ejecta. We suggest that the origin of the
plasma in this region is the interstellar medium (ISM). In the "normal"
abundance regions, we confirm that abundances are depleted to the solar values
by a factor of about 5 that is not expected in the ISM around the Cygnus Loop.
Introduction of non-thermal emission in our model fitting can not naturally
resolve the abundance-depletion problem. The origin of the depletion still
remains as an open question.Comment: 18 pages, 6 figure
Performance of a newly developed SDCCD for X-ray use
A Scintillator Deposited CCD (SDCCD) is a wide-band X-ray detector consisting
of a CCD and a scintillator directly attached to each other. We assembled the
newly developed SDCCD that the scintillator CsI(Tl) is below the fully depleted
CCD. The incident X-rays enter the CCD depletion layer first. Then, X-rays
passing through the depletion layer are absorbed in the CsI(Tl). The contact
surface of the CCD is a back-illuminated side so that we can have good light
collection efficiency. In our experimental setup, we confirmed good performance
of our SDCCD detecting many emission lines up to 88\,keV that comes from
Cd.Comment: 4 pages, 6 figures, accepted publication for Nucl. Instr. and Meth.
(2010
Investigation of simulated annealing method and its application to optimal design of die mold for orientation of magnetic powder
Factors affecting the convergence characteristics and results obtained by the optimal design method using the finite element method and simulated annealing are investigated systematically, and the optimal parameters for simulated annealing method are obtained. The optimal shape of the die mold for orientation of the magnetic powder (nonlinear magnetostatic problem) is obtained using finite elements and simulated annealing. The experimental verification is also carried out </p
Effect of minor loop on magnetic characteristics of permanent magnet type of MRI
A modeling technique of the minor loop using typical hysteresis loops is shown. The effect of the minor loop and eddy current in the pole piece of a permanent magnet type of MRI on the residual flux density of the probe coil is examined. It is illustrated that the change ΔB of residual flux density occurs due to the minor loop of the pole piece. It is also pointed out that the choice of time interval Δt is important in a nonlinear analysis considering the minor loop</p
Effects of residual magnetism due to minor loop on magnetic property of permanent magnet type of MRI
Summary form only given. The flux distribution of a permanent magnet type of MRI shown in Fig.1 is affected by the hysteresis (minor loop) and eddy currents in the pole piece and yoke due to the pulse current (Fig.2) of the gradient coil. In this paper, the effects of the hysteresis and the eddy current in the yoke on the residual flux density of the probe coil are investigated. It can be assumed that the eddy current does not flow in the pole piece because it is divided into pieces. The eddy current flows in the yoke. Fig.3 shows the change of residual flux density /spl Delta/B/sub z/ at the point S(0,0) in Fig.1. /spl Delta/B/sub z/ is given by /spl Delta/B/sub z/=B/sub z1/-B/sub z0/ (1), where B/sub z0/ is the flux density at the instant t=0(I=0A). B/sub z1/ is the flux density at the instant t=i(I=0A). The instant of 1,2,3,... in Fig.2 corresponds to 1,2,3,... in Fig.3. Fig.3 shows that the hysteresis in the pole piece and yoke should be taken into account. The effect of eddy current in the yoke on the residual flux density /spl Delta/B/sub z/ is not negligible. These results suggests that the reduction of the amplitudes of minor loop and eddy current is important in order to improve the operating characteristics of the permanent magnet type of MRI.</p
The X-Ray Structure of the Supernova Remnant 3C 400.2
We present here the results of an X-ray study of the supernova remnant 3C
400.2 (G53.6-2.2) using the ASCA data. 3C 400.2 has an unusual morphology at
radio wavelengths, suggesting two SNRs superposed along the same line of sight,
whereas its X-ray emission is known to be centrally peaked. We investigated the
X-ray spectral variation across the remnant using the ASCA GIS and the ROSAT
PSPC data. The X-ray spectra can be well fitted by thin thermal plasma models.
However, there is no significant variation in the temperature and the
ionization parameter across the remnant. We conclude that it is a single SNR
rather than two overlapping SNRs. The centrally peaked X-ray morphology and the
thin thermal emission with nearly cosmic abundances indicate that 3C 400.2
belongs to a class of ``mixed-morphology SNRs''. We found that the physical
parameters of 3C 400.2 are similar to those of other mixed-morphology SNRs. The
morphology of 3C 400.2 can be explained by a supernova explosion occurring near
to the edge of an interstellar cloud.Comment: 8 pages, 4 figures, to appear in PASJ vol. 5
Analysis of the magnetic property of a permanent-magnet-type MRI - Behavior of residual magnetization
The minor loops of B and H of steel due to pulse excitation and eddy currents induced in steel affect the magnetic characteristics of a permanent-magnet-type MRI. In this paper, the magnetic properties of a permanent magnet assembly is examined by using the finite-element method taking into account minor loop. The distribution of residual magnetization in the yoke is illustrated, and the effect of residual magnetization on the behavior of residual flux density is examined. It is shown that the behavior of B and H in minor loops is affected by the eddy currents in the yoke and pole piece.</p
ILD CAUSED BY ANTIFIBROTIC AGENTS
Interstitial lung disease (ILD), as an adverse effect of certain drugs, leads to inflammation and damage in the walls of the alveoli, making it difficult for the alveoli to take up oxygen. Interstitial pneumonia with no identifiable cause is called idiopathic interstitial pneumonia (IIP), and, among the major IIPs, idiopathic pulmonary fibrosis (IPF) is diagnosed in about half of patients. Current treatment options are limited, among which the antifibrotic drugs nintedanib (Ofev) and pirfenidone (Pirespa) are the first-line drugs. In this study, we investigated the incidence of ILD possibly caused by antifibrotic agents using data from the Japanese Adverse Drug Event Report (JADER) database, a database of spontaneous adverse event reports published by the Pharmaceuticals and Medical Devices Agency (PMDA), and the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS), published by the FDA. We used the FAERS and JADER to detect the signals of adverse events on the basis of reporting odds ratios. The relationship between indications and adverse events was clarified by separating indications and adverse events using the spontaneous adverse event reporting database with novel drug involvement. Regarding the involvement of nintedanib and pirfenidone in the development of ILD, JADER and FAERS showed signals for both nintedanib and pirfenidone as suspect drugs, and no signals for nintedanib or pirfenidone as concomitant drug interactions were detected. We highlight this because there are only a few effective drugs for IPF, and effective and safe drug therapies should be implemented by taking into consideration drug-induced ILD
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