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Search Results: 1 - 10 of 117949 matches for " Nagase T "
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Formation of nanocrystalline structure during electron irradiation induced crystallization in amorphous Fe–Zr–B alloys
T. Nagase, Y. Umakoshi and N. Sumida
Science and Technology of Advanced Materials , 2002,
Abstract: Effect of electron irradiation on the crystallization and phase stability of Fe88Zr9B3 and Fe71Zr9B20 amorphous alloys was examined. Electron irradiation at an accelerated voltage of 2000 kV was performed at room temperature. The Fe71Zr9B20 alloy showed a wide supercooled liquid region and the ΔTx value was 71 K, while no glass transition was observed in Fe88Zr9B3 alloy. The amorphous phase in Fe–Zr–B alloys was not stable under irradiation and crystallization from the amorphous phase was accelerated by the irradiation. Nanocrystalline structure composed of α-Fe and cubic-Fe2Zr was formed in Fe88Zr9B3 alloy by irradiation induced crystallization, while no nanoscale precipitates of intermetallic compounds were formed during annealing. In Fe71Zr9B20 alloy, the formation of nanocrystalline precipitates was also confirmed by irradiation induced crystallization, although the formation of nanocrystalline structure had not been realized in high B concentration Fe–Zr–B alloys by annealing. These new results show that electron irradiation is effective in producing a new nanocrystalline structure.
Dynamic change in respiratory resistance during inspiratory and expiratory phases of tidal breathing in patients with chronic obstructive pulmonary disease
Yamauchi Y, Kohyama T, Jo T, Nagase T
International Journal of Chronic Obstructive Pulmonary Disease , 2012, DOI: http://dx.doi.org/10.2147/COPD.S30399
Abstract: amic change in respiratory resistance during inspiratory and expiratory phases of tidal breathing in patients with chronic obstructive pulmonary disease Original Research (2242) Total Article Views Authors: Yamauchi Y, Kohyama T, Jo T, Nagase T Published Date April 2012 Volume 2012:7 Pages 259 - 269 DOI: http://dx.doi.org/10.2147/COPD.S30399 Received: 31 January 2012 Accepted: 04 March 2012 Published: 11 April 2012 Yasuhiro Yamauchi1,2, Tadashi Kohyama2, Taisuke Jo2, Takahide Nagase2 1Division of Health Promotion Center, 2Department of Respiratory Medicine, University of Tokyo, Tokyo, Japan Background and objective: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation consisting of airway obstruction and parenchymal emphysema, with loss of elastic recoil. The forced oscillation technique can detect impairment of lung function by measuring lung impedance during normal tidal breathing. Respiratory resistance (Rrs) in COPD has been well-studied, but the differences in Rrs in the inspiratory and expiratory phases between mild and moderate COPD remain poorly understood. Since airway obstruction in COPD is known to change dynamically during tidal breathing and might affect Rrs, the differences in Rrs during tidal breathing between mild and moderate COPD were evaluated. Methods: Mild (n = 13) and moderate (n = 13) COPD patients were recruited at Tokyo University Hospital (Tokyo, Japan). Rrs was measured using MostGraph-01 (Chest MI, Inc, Tokyo, Japan), which depicted Rrs in a frequency- and respiratory cycle-dependent manner in three-dimensional graphics. Rrs was evaluated at 4–35 Hz during tidal breathing. Results: Rrs changed dynamically during tidal breathing in COPD. The mean Rrs values were significantly greater in the moderate COPD group than in the mild group. The maximal and minimal Rrs values at higher frequencies in the respiratory cycle were significantly greater in moderate COPD. In inspiratory–expiratory breath analysis, the maximal and minimal Rrs values at 20 Hz and 35 Hz were significantly greater in the moderate group, whereas at 4 Hz they did not differ significantly between the groups. Conclusion: Rrs changed dynamically during tidal breathing in patients with COPD. The Rrs values at higher frequencies were greater in moderate COPD than in mild COPD. Rrs at higher frequencies might reflect the degree of airway obstruction in tidal breathing in patients with COPD and might be a useful marker for evaluation of airway obstruction at an early stage of COPD.
Dynamic change in respiratory resistance during inspiratory and expiratory phases of tidal breathing in patients with chronic obstructive pulmonary disease
Yamauchi Y,Kohyama T,Jo T,Nagase T
International Journal of COPD , 2012,
Abstract: Yasuhiro Yamauchi1,2, Tadashi Kohyama2, Taisuke Jo2, Takahide Nagase21Division of Health Promotion Center, 2Department of Respiratory Medicine, University of Tokyo, Tokyo, JapanBackground and objective: Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation consisting of airway obstruction and parenchymal emphysema, with loss of elastic recoil. The forced oscillation technique can detect impairment of lung function by measuring lung impedance during normal tidal breathing. Respiratory resistance (Rrs) in COPD has been well-studied, but the differences in Rrs in the inspiratory and expiratory phases between mild and moderate COPD remain poorly understood. Since airway obstruction in COPD is known to change dynamically during tidal breathing and might affect Rrs, the differences in Rrs during tidal breathing between mild and moderate COPD were evaluated.Methods: Mild (n = 13) and moderate (n = 13) COPD patients were recruited at Tokyo University Hospital (Tokyo, Japan). Rrs was measured using MostGraph-01 (Chest MI, Inc, Tokyo, Japan), which depicted Rrs in a frequency- and respiratory cycle-dependent manner in three-dimensional graphics. Rrs was evaluated at 4–35 Hz during tidal breathing.Results: Rrs changed dynamically during tidal breathing in COPD. The mean Rrs values were significantly greater in the moderate COPD group than in the mild group. The maximal and minimal Rrs values at higher frequencies in the respiratory cycle were significantly greater in moderate COPD. In inspiratory–expiratory breath analysis, the maximal and minimal Rrs values at 20 Hz and 35 Hz were significantly greater in the moderate group, whereas at 4 Hz they did not differ significantly between the groups.Conclusion: Rrs changed dynamically during tidal breathing in patients with COPD. The Rrs values at higher frequencies were greater in moderate COPD than in mild COPD. Rrs at higher frequencies might reflect the degree of airway obstruction in tidal breathing in patients with COPD and might be a useful marker for evaluation of airway obstruction at an early stage of COPD.Keywords: COPD, airflow limitation, respiratory resistance, forced oscillation technique
Optically Induced Nuclear Spin Polarization in the Quantum Hall Regime: The Effect of Electron Spin Polarization through Exciton and Trion Excitations
K. Akiba,S. Kanasugi,T. Yuge,K. Nagase,Y. Hirayama
Physics , 2014,
Abstract: We study nuclear spin polarization in the quantum Hall regime through the optically pumped electron spin polarization in the lowest Landau level. The nuclear spin polarization is measured as a nuclear magnetic field $B_N$ by means of the sensitive resistive detection. We find the dependence of $B_N$ on filling factor unmonotonous. The comprehensive measurements of $B_N$ with the help of the circularly polarized photoluminescence measurements indicate the participation of the photo-excited complexes i.e., the exciton and trion (charged exciton), in nuclear spin polarization. On the basis of a novel estimation method of the equilibrium electron spin polarization, we analyze the experimental data and conclude that the filling factor dependence of $B_N$ is understood by the effect of electron spin polarization through excitons and trions.
Study of the Long Term Stability of two Anomalous X-ray Pulsars 4U 0142+61 and 1E 1048.1-5937 with ASCA
B. Paul,M. Kawasaki,T. Dotani,F. Nagase
Physics , 2000, DOI: 10.1086/309028
Abstract: We present new observations of two anomalous X-ray pulsars (AXP) 4U 0142+61 and 1E 1048.1-5937 made in 1998 with the ASCA. The energy spectra of these two AXPs are found to consist of two components, a power-law and a blackbody emission from the neutron star surface. These observations, when compared to earlier ASCA observations in 1994 show remarkable stability in the intensity, spectral shape and pulse profile. However, we find that the spin-down rate in 1E 1048.1-5937 is not constant. In this source, we have clearly identified three epochs with spin-down rates different from each other and the average value. This has very strong implications for the magnetar hypothesis of AXPs. We also note that the spin-down rate and its variations in 1E 1048.1-5937 are much larger than what can normally be produced by an accretion disk with very low mass accretion rate corresponding to its low X-ray luminosity.
Detection of hard X-rays from a Class I protostar in the HH24-26 region in the Orion Molecular Cloud
H. Ozawa,F. Nagase,Y. Ueda,T. Dotani,M. Ishida
Physics , 1999, DOI: 10.1086/312247
Abstract: We observed the HH24-26 region in the L1630 Orion molecular cloud complex with the X-ray observatory ASCA in the 0.5$-$10 keV band. X-ray emission was detected from the T Tauri star SSV61 and from the region where the Class I protostars SSV63E and SSV63W are located (hereafter SSV63E+W). The spectra of both SSV63E+W and SSV61 are well explained by an optically thin thermal plasma model. The spectrum of the T Tauri star SSV61 has a low temperature of $kT=0.9$ (0.7$-$1.2) keV and a moderate absorption of $N_{\rm{H}}=1.3$ (0.9$-$1.7) $\times10^{22}$ cm$^{-2}$, while that of the protostar SSV63E+W has a high temperature of $kT=5.0$ (3.3$-$7.9) keV and a heavy absorption of $N_{\rm{H}}=1.5$ (1.2$-$1.8) $\times10^{23}$ cm$^{-2}$. The X-ray light curve of SSV63E+W showed a flare during the observation. The peak flux reached about 9 times that of the quiescent flux. The temperature and the absorption column density do not change conspicuously during the flare. The 0.5$-$10 keV luminosity of SSV63E+W was about $1\times10^{32}$ erg s$^{-1}$ in the quiescent state. The present detection of hard X-rays from SSV63E+W is remarkable, because this is the first X-ray detection of a protostar in Orion.
Optically induced nuclear spin polarization in a single GaAs/AlGaAs quantum well probed by a resistance detection method in the fractional quantum Hall regime
K. Akiba,T. Yuge,S. Kanasugi,K. Nagase,Y. Hirayama
Physics , 2012, DOI: 10.1103/PhysRevB.87.235309
Abstract: We study the optically pumped nuclear spin polarization in a single GaAs/AlGaAs quantum well in the quantum Hall system. We apply resistive detection via the contact hyperfine interaction, which provides high sensitivity and selectivity, to probe a small amount of polarized nuclear spins in a single well. The properties of the optical nuclear spin polarization are clearly observed. We theoretically discuss the nuclear spin dynamics accompanied with doped electrons to analyze the experimental data. The optical nuclear polarization spectra exhibit electron-spin-resolved lowest Landau level interband transitions. We find that the phonon emission process, which normally assists the optical pumping process, influences the optical nuclear spin polarization. We also discuss that the electron-electron interaction can play an important role in the optical nuclear spin polarization.
La liberté bergsonienne et la responsabilité
Masae Nagase
Meta : Research in Hermeneutics, Phenomenology and Practical Philosophy , 2011,
Abstract: In the Essay Bergson defines personal expression as free. A free act is the expression of the conception of life found in a person’s experience of life. Given that it is different for everyone, it cannot be expressed in language. That is why Bergson considers that the act which is the most free is one that is done without any reason. It can be said that Bergson himself felt the need to ground his conception of responsibility. In the Cours II he states two conditions of responsibility: freedom and discernment. The identity of a person which ensures that freedom is based in the conception of duration found in the Essay. In Matter and Memory Bergson tries to resolve the question of discernment with the help of his theory of memory. Bergson succeeded in solving the problems related to reason and to fanciful decision and solidly established the notion of responsibility while renewing the theory of freedom originally found in the Essay.
ASCA observations of the iron K complex of Circinus X-1 near zero phase: spectral evidence for partial covering
W. N. Brandt,A. C. Fabian,T. Dotani,F. Nagase,H. Inoue,T. Kotani,Y. Segawa
Physics , 1996, DOI: 10.1093/mnras/283.3.1071
Abstract: We report on ASCA energy spectra of Cir X-1 taken near its zero phase on 1994 August 4-5. The ASCA SIS detectors allow a more detailed study of the iron K complex than has been possible before. We find that prior to a sudden upward flux transition the dominant iron K feature appears to consist of a large edge from neutral or nearly-neutral iron. The depth of the edge corresponds to an absorption column of about 1.5E24 cm^{-2}, while little absorption over that expected from the Galaxy is seen at lower X-ray energies. The differential absorption at high and low X-ray energies combined with the iron edge energy are strong evidence that partial covering is a crucial determinant of the behaviour observed from Cir X-1. The continuum spectral variability observed by ASCA can also be understood naturally in terms of partial covering column changes. There is evidence for a relatively weak emission line from neutral iron with an equivalent width of only about 65 eV. After the flux transition, the strength of the edge feature is greatly reduced, suggesting a large reduction in the amount of partial covering. For a large region of statistically acceptable chi-squared parameter space, the luminosity of Cir X-1, after correction for partial covering, need not change during the transition. We discuss models for the partial covering and suggest that X-ray scattering by electrons may be important. Aspects of the Cir X-1 spectrum are very similar to those of Seyfert 2 galaxies with Compton-thin tori.
Nature of the Soft Spectral Component in the X-ray Pulsars SMC X-1 and LMC X-4
B. Paul,F. Nagase,T. Endo,T. Dotani,J. Yokogawa,M. Nishiuchi
Physics , 2002, DOI: 10.1086/342701
Abstract: We present here the results of an investigation of the pulse averaged and pulse phase resolved energy spectra of two high luminosity accretion powered X-ray pulsars SMC X-1 and LMC X-4 made with ASCA. The phase averaged energy spectra definitely show the presence of a soft excess in both the sources. If the soft excess is modeled as a separate black-body or thermal bremsstrahlung type component, pulse phase resolved spectroscopy of SMC X-1 shows that the soft component also has a pulsating nature. Same may be true for LMC X-4, though a very small pulse fraction limits the statistical significance. The pulsating soft component is found to have a nearly sinusoidal profile, dissimilar to the complex profile seen at higher energies, which can be an effect of smearing. Due to very high luminosity of these sources, the size of the emission zone required for the soft component is large (radius ~300-400 km). We show that the pulsating nature of the soft component is difficult to explain if a thermal origin is assumed for it. We further investigated with alternate models, like inversely broken power-law or two different power-law components and found that these models can also be used to explain the excess at low energy. A soft power-law component may be a common feature of the accreting X-ray pulsars, which is difficult to detect because most of the HMXB pulsars are in the Galactic plane and experience large interstellar absorption. In LMC X-4, we have also measured two additonal mid-eclipse times, which confirm the known orbital decay.
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