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Toyoda, Shin*; Inoue, Kazuhiko*; Yamaguchi, Ichiro*; Hoshi, Masaharu*; Hirota, Seiko*; Oka, Toshitaka; Shimazaki, Tatsuya*; Mizuno, Hideyuki*; Tani, Atsushi*; Yasuda, Hiroshi*; et al.
Radiation Protection Dosimetry, 199(14), p.1557 - 1564, 2023/09
Times Cited Count：2 Percentile：28.31(Environmental Sciences)Interlaboratory comparison studies are important for radiation dosimetry in order to demonstrate how the technique is universally available. The set of standard samples are examined in each participating laboratory in the present study. After a set of standard samples together with the samples with unknown doses, which were prepared in the same laboratory as the standard samples, are measured at a participating laboratory, those samples are sent to another participating laboratory for next measurement. There is some small difference observed in the sensitivity (the slope of the dose response line) of the standard samples while the differences in the obtained doses for the samples with unknown doses are rather systematic, implying that the difference is mostly due to the samples but not to measurements.
Li, M.*; Nagashio, Kosuke*; Ishikawa, Takehiko*; Mizuno, Akitoshi*; Adachi, Masayoshi*; Watanabe, Masahito*; Yoda, Shinichi*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Acta Materialia, 56(11), p.2514 - 2525, 2008/06
Times Cited Count：25 Percentile：70.36(Materials Science, Multidisciplinary)Co-61.8 at.% Si (CoSe-CoSi
) eutectic alloys were solidified on an electromagnetic levitator (EML) and an electrostatic levitator (ESL) at different undercooling levels. The results indicated that there is only a single recalescence event at low undercooling with the CoSi intermetallic compound as primary phase, which is independent of processing facilities, on either an EML or an ESL. The microstructure, however, is strongly dependent on the processing facility. On high undercooling, double recalescence takes place regardless of levitation condition. In situ X-ray diffraction of alloys solidified on the EML demonstrates that the CoSi compound becomes the primary phase upon the first recalescence, and the CoSi intermetallic phase crystallizes during the second recalescence. In addition to phase identification, real-time diffraction patterns can also provide additional evidence of the fragmentation of the primary phase.
identification of the metastable phase during solidification from the undercooled YFeO
melt by fast X-ray diffractometry at 250 HzNagashio, Kosuke*; Kuribayashi, Kazuhiko*; Vijaya Kumar, M. S.*; Niwata, Kenji*; Hibiya, Taketoshi*; Mizuno, Akitoshi*; Watanabe, Masahito*; Katayama, Yoshinori
Applied Physics Letters, 89(24), p.241923_1 - 241923_3, 2006/12
Times Cited Count：23 Percentile：60.97(Physics, Applied)A time-resolved X-ray diffraction (XRD) experiment at 250 Hz using a synchrotron radiation source was carried out during the containerless solidification of ReFeO (Re=Y and Lu) in order to identify the metastable phase 
. The metastable phase solidified primarily from the undercooled YFeO melt finally transformed to the stable orthorhombic YFeO phase during the short period of recalescence (
0.035 s). Although the metastable phase could not be detected in the as-solidified sample by the powder XRD, the successfully obtained diffraction pattern of the metastable phase in the YFeO system was consistent with that of the metastable hexagonal LuFeO phase.
Nagashio, Kosuke*; Adachi, Masayoshi*; Higuchi, Kensuke*; Mizuno, Akitoshi*; Watanabe, Masahito*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Journal of Applied Physics, 100(3), p.033524_1 - 033524_6, 2006/08
Times Cited Count：15 Percentile：47.70(Physics, Applied)Grain refined microstructure is often obtained spontaneously in the solidification of metals and semiconductors from the undercooled melt without any external forces. Although it has been reported that the grain refinement is mainly caused by the fragmentation of the dendrites, the dynamic process of the fragmentation of dendrites has not been fully understood because the microstructure after the solidification has been analyzed. Here, we present a time-resolved 2- dimensional X-ray diffraction experiment on the solidification of Si from the undercooled melt. The number of diffraction spots observed at low undercoolings (
100K) did not increase at the plateau stage, while the diffraction pattern at medium undercoolings (100K
200K) changed from the spots with the tail to rings with the lapse of time. Both this result and high speed video imaging suggested that the high-order arms of the dendrites mostly detached from the main stems because nucleation could not be expected at the melting point after recalescence. The several spots observed at low undercoolings drastically changed to rings at high undercoolings (
200K), which indicated the complete fragmentation of dendrite main stem as well as high-order arms. This complete fragmentation resulted in the grain refined microstructure.
Higuchi, Kensuke*; Kimura, Kakuryo*; Mizuno, Akitoshi*; Watanabe, Masahito*; Katayama, Yoshinori; Kuribayashi, Kazuhiko*
Measurement Science and Technology, 16(2), p.381 - 385, 2005/02
Times Cited Count：45 Percentile：86.63(Engineering, Multidisciplinary)X-ray diffraction and density measurements have been simultaneously performed to investigate the atomic structure of molten silicon in wide temperature range including undercooling region by using the electromagnetic levitation technique. The density was obtained from the mass and the shape of levitated sample by non-contact method based on the image analysis technique. X-ray diffraction experiments were performed by using the synchrotron radiation at SPring8, Japan. From structural analysis of undercooled molten silicon, first nearest neighbour coordination numbers and interatomic distances were about 5 and 2.48
with no dependence on temperature in the range of 1900-1550 K. We conclude as a result that the short-range order based on tetrahedral bonds of undercooled molten silicon does not change with the degree of undercoolings but medium-range order changes by the degree of undercoolings.
; Ichinose, Yuji; ; Sasuga, Tsuneo; ;
J. Org. Chem., 63(10), p.3204 - 3212, 1998/00
Times Cited Count：25 Percentile：63.80(Chemistry, Organic)no abstracts in English
thin films by combination of lithographic photoirradiation and pyrolysis of an organotin polymer; Ichinose, Yuji; Kawanishi, Shunichi; Nishii, Masanobu; Sasuga, Tsuneo; ;
Chemistry of Materials, 9(12), p.2674 - 2675, 1997/00
Times Cited Count：18 Percentile：61.37(Chemistry, Physical)no abstracts in English
Ichinose, Yuji; ; Kawanishi, Shunichi; ;
Langmuir, 13(10), p.2603 - 2605, 1997/00
Times Cited Count：8 Percentile：44.72(Chemistry, Multidisciplinary)no abstracts in English
; ; Ichinose, Yuji; Kawanishi, Shunichi; ;
Polymer, 37(24), p.5525 - 5528, 1996/00
Times Cited Count：17 Percentile：58.30(Polymer Science)no abstracts in English
Todaka, Azumi*; Toyoda, Shin*; Tachi, Momoko*; Shimazaki, Tatsuya*; Oka, Toshitaka; Yamaguchi, Ichiro*; Inoue, Kazuhiko*; Yasuda, Hiroshi*; Hirota, Seiko*; Tani, Atsushi*; et al.
no journal, ,
To estimate the external exposure dose using electron spin resonance technique, we use a "standard sample" which were prepared at each laboratory with each preparation protocol. It is necessary to unite the preparation protocol for the "real" standard sample. In the point of view of the enamel extraction method, no difference was observed for five dose responses between the absorbed dose and the CO
radical intensity.
