10 research outputs found
Delaying repatriation: Japanese technicians in early postwar China
Research on the Japanese living in Manchukuo in August 1945 has generally fostered the assumption that all Japanese there wanted to return to Japan as soon as possible. Yet, some made the conscious and voluntary decision to stay, at least for the short to medium term. Among those who chose to delay repatriation were a number of technicians employed by Mantetsuâs (South Manchurian Railroad Company) ChÂŻuo Shikenjo. This paper looks at the political and personal realities faced by these technicians when making their decisions as whether to stay or leave in terms of the concepts of voluntary and involuntary repatriation. It shows that the circumstances faced, and consequently the decisions made by the technicians, differed over time. It argues that there were three main reasons behind any decision to stay: pragmatism, a sense of responsibility for Japanâs activities during the war and a sense of loyalty
Molecular dynamics simulations for microscopic behavior of water molecules in the vicinity of zwitterionic self-assembled monolayers
Assessment of the Antifouling Properties of Polyzwitterions from Free Energy Calculations by Molecular Dynamics Simulations
Pseudomonas-Derived Ceramidase Induces Production of Inflammatory Mediators from Human Keratinocytes via Sphingosine-1-Phosphate
Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer
The Crab nebula originated from a core-collapse supernova (SN) explosion
observed in 1054 A.D. When viewed as a supernova remnant (SNR), it has an
anomalously low observed ejecta mass and kinetic energy for an Fe-core collapse
SN. Intensive searches were made for a massive shell that solves this
discrepancy, but none has been detected. An alternative idea is that the SN1054
is an electron-capture (EC) explosion with a lower explosion energy by an order
of magnitude than Fe-core collapse SNe. In the X-rays, imaging searches were
performed for the plasma emission from the shell in the Crab outskirts to set a
stringent upper limit to the X-ray emitting mass. However, the extreme
brightness of the source hampers access to its vicinity. We thus employed
spectroscopic technique using the X-ray micro-calorimeter onboard the Hitomi
satellite. By exploiting its superb energy resolution, we set an upper limit
for emission or absorption features from yet undetected thermal plasma in the
2-12 keV range. We also re-evaluated the existing Chandra and XMM-Newton data.
By assembling these results, a new upper limit was obtained for the X-ray
plasma mass of <~ 1Mo for a wide range of assumed shell radius, size, and
plasma temperature both in and out of the collisional equilibrium. To compare
with the observation, we further performed hydrodynamic simulations of the Crab
SNR for two SN models (Fe-core versus EC) under two SN environments (uniform
ISM versus progenitor wind). We found that the observed mass limit can be
compatible with both SN models if the SN environment has a low density of <~
0.03 cm-3 (Fe core) or <~ 0.1 cm-3 (EC) for the uniform density, or a
progenitor wind density somewhat less than that provided by a mass loss rate of
10-5 Mo yr-1 at 20 km s-1 for the wind environment.Comment: PASJ in press. Figures are now properly include
Search for thermal X-ray features from the Crab nebula with the Hitomi soft X-ray spectrometer
Hitomi X-ray observation of the pulsar wind nebula G21.50.9
International audienceWe present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5â0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8â80âkeV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Î_1 = 1.74 ± 0.02 and Î_2 = 2.14 ± 0.01 below and above the break at 7.1 ± 0.3âkeV, which is significantly lower than the NuSTAR result (âŒ9.0âkeV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833â1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345âkeV and 9.296âkeV with a significance of 3.65âÏ. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter
Search for thermal X-ray features from the Crab nebula with Hitomi Soft X-ray Spectrometer
The Crab nebula originated from a core-collapse supernova (SN) explosion
observed in 1054 A.D. When viewed as a supernova remnant (SNR), it has
an anomalously low observed ejecta mass and kinetic energy for an
Fe-core collapse SN. Intensive searches were made for a massive shell
that solves this discrepancy, but none has been detected. An alternative
idea is that the SN1054 is an electron-capture (EC) explosion with a
lower explosion energy by an order of magnitude than Fe-core collapse
SNe. In the X-rays, imaging searches were performed for the plasma
emission from the shell in the Crab outskirts to set a stringent upper
limit to the X-ray emitting mass. However, the extreme brightness of the
source hampers access to its vicinity. We thus employed spectroscopic
technique using the X-ray micro-calorimeter onboard the Hitomi
satellite. By exploiting its superb energy resolution, we set an upper
limit for emission or absorption features from yet undetected thermal
plasma in the 2-12 keV range. We also re-evaluated the existing Chandra
and XMM-Newton data. By assembling these results, a new upper limit was
obtained for the X-ray plasma mass o