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Journal Articles

Analysis of the high-dose-range radioresistance of prostate cancer cells, including cancer stem cells, based on a stochastic model

Saga, Ryo*; Matsuya, Yusuke; Takahashi, Rei*; Hasegawa, Kazuki*; Date, Hiroyuki*; Hosokawa, Yoichiro*

Journal of Radiation Research, 60(3), p.298 - 307, 2019/05

In radiotherapy, it is recognized that cancer stem cells (CSCs) in tumor tissue shows radio-resistance. However, the relationship between content percentage of the CSCs and dose-response curve on cell survival remain unclear. In this study, we developed a stochastic model considering progeny cells and stem cells, and investigated the impact of stem cells on radio-sensitivity. From the flow-cytometric analysis (cell experiments), the content percentage of stem cells was 3.2% or less which agreed well with the model estimation from the cell survival curve. Based on the verification, it is suggested that cell survival in high-dose range is largely affected by the CSCs. In addition, regarding the sub-population of stem cells, the present model well reproduces the dose response on lethal lesions to DNA comparing with the conventional LQ model. This outcome indicates that the stem cells must be considered for describing the dose-response curve in wide dose range.

Journal Articles

Development of compact high field pulsed magnet system for new sample environment equipment at MLF in J-PARC

Watanabe, Masao; Nojiri, Hiroyuki*; Ito, Shinichi*; Kawamura, Seiko; Kihara, Takumi*; Masuda, Takatsugu*; Sahara, Takuro*; Soda, Minoru*; Takahashi, Ryuta

JPS Conference Proceedings (Internet), 25, p.011024_1 - 011024_5, 2019/03

Recently, neutron scattering experiments have been rapidly progressed under high magnetic field. In the J-PARC, proto-type compact pulse magnet system with the power supply, the coil and the sample stick has been developed. Basic specifications of the power supply are as follows; maximum charged voltage with capacitor is 2 kV, maximum current is 8 kA, repetition rate is a pulse per several minutes and pulse duration is several msec. Maximum magnetic field in the coil is more than 30 Tesla. The sample stick is designed for Orange-Cryostat. In this presentation, We report the details of the pulsed magnet system and the performance of it on neutron scattering experiments at MLF beam line (HRC).

Journal Articles

Gamma-ray imaging system for Fukushima Daiichi Nuclear Power Plant using silicon strip detector

Kaburagi, Masaaki; Sato, Yuki; Yoshihara, Yuri*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Torii, Tatsuo

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.405 - 414, 2018/11

Journal Articles

Fabrication and magnetic control of Y$$_3$$Fe$$_5$$O$$_{12}$$ cantilevers

Seo, Y.-J.*; Harii, Kazuya; Takahashi, Ryo*; Chudo, Hiroyuki; Oyanagi, Koichi*; Qiu, Z.*; Ono, Takahito*; Shiomi, Yuki*; Saito, Eiji

Applied Physics Letters, 110(13), p.132409_1 - 132409_4, 2017/03

 Times Cited Count:4 Percentile:43.58(Physics, Applied)

We have fabricated ferrite cantilevers in which their vibrational properties can be controlled by external magnetic fields. Submicron-scale cantilever structures were made from Y$$_3$$Fe$$_5$$O$$_{12}$$ films by physical etching combined with the use of a focused ion beam milling technique. We found that the cantilevers exhibit two resonance modes which correspond to horizontal and vertical vibrations. Under external magnetic fields, the resonance frequency of the horizontal mode increases, while that of the vertical mode decreases, quantitatively consistent with our numerical simulation for magnetic forces. The changes in resonance frequencies with magnetic fields reach a few percent, showing that an efficient magnetic control of resonance frequencies was achieved.

Journal Articles

Field test around Fukushima Daiichi Nuclear Power Plant site using improved Ce:Gd$$_{3}$$(Al,Ga)$$_{5}$$O$$_{12}$$ scintillator Compton camera mounted on an unmanned helicopter

Shikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.

Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12

 Times Cited Count:11 Percentile:6.81(Nuclear Science & Technology)

The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4$$times$$4 to 8$$times$$8 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m $$times$$ 60 m and 65 m $$times$$ 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the $$gamma$$-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10$$^{circ}$$).

Journal Articles

Age and speciation of iodine in groundwater and mudstones of the Horonobe area, Hokkaido, Japan; Implications for the origin and migration of iodine during basin evolution

Togo, Yoko*; Takahashi, Yoshio*; Amano, Yuki; Matsuzaki, Hiroyuki*; Suzuki, Yohei*; Terada, Yasuko*; Muramatsu, Yasuyuki*; Ito, Kazumasa*; Iwatsuki, Teruki

Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10

 Times Cited Count:7 Percentile:35.46(Geochemistry & Geophysics)

Iodine distribution, speciation, and isotope ratio ($$^{129}$$I/$$^{127}$$I) in both rock and groundwater phases were determined to investigate long-term migration of iodine in diatomaceous and siliceous shale. It was suggested that I$$^{-}$$ is released to the ground water during the progress of the maturation of organic matter. Dissociated I$$^{-}$$ could move toward the surface because of the upward water flow driven by the compaction during burial diagenetic process. Thus, iodine rich brine is created by integration of iodine released from underlying formations. Because of low affinity of I$$^{-}$$ to solid phase, released I$$^{-}$$ remains in solution phase, and the concentration of the iodine in the solution has been possibly increasing during sedimentation history.

Journal Articles

SENJU; A New time-of-flight single-crystal neutron diffractometer at J-PARC

Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.

Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02

 Times Cited Count:13 Percentile:11.41(Chemistry, Multidisciplinary)

Journal Articles

Spin hydrodynamic generation

Takahashi, Ryo*; Matsuo, Mamoru; Ono, Masao; Harii, Kazuya; Chudo, Hiroyuki; Okayasu, Satoru; Ieda, Junichi; Takahashi, Saburo*; Maekawa, Sadamichi; Saito, Eiji

Nature Physics, 12, p.52 - 56, 2016/01

 Times Cited Count:24 Percentile:7.93(Physics, Multidisciplinary)

Journal Articles

Barnett effect in paramagnetic states

Ono, Masao; Chudo, Hiroyuki; Harii, Kazuya; Okayasu, Satoru; Matsuo, Mamoru; Ieda, Junichi; Takahashi, Ryo*; Maekawa, Sadamichi; Saito, Eiji

Physical Review B, 92(17), p.174424_1 - 174424_4, 2015/11

 Times Cited Count:10 Percentile:36.72(Materials Science, Multidisciplinary)

Journal Articles

J-PARC E19 experiment; Pentaquark $$Theta^+$$ search in hadronic reaction at J-PARC

Takahashi, Tomonori*; Ekawa, Hiroyuki; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Sugimura, Hitoshi; Tanida, Kiyoshi; et al.

JPS Conference Proceedings (Internet), 8, p.022011_1 - 022011_6, 2015/09

Journal Articles

Cosmic-ray test of a time-of-flight detector for double-strangeness experiments at J-PARC

Kim, S. H.*; Hwang, S.; Ahn, J. K.*; Ekawa, Hiroyuki; Hayakawa, Shuhei; Hong, B.*; Hosomi, Kenji; Imai, Kenichi; Kim, M. H.*; Lee, J. Y.*; et al.

Nuclear Instruments and Methods in Physics Research A, 795, p.39 - 44, 2015/09

 Times Cited Count:1 Percentile:81.41(Instruments & Instrumentation)

Journal Articles

Precise determination of $$^{12}_{Lambda}$$C level structure by $$gamma$$-ray spectroscopy

Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08

 Times Cited Count:6 Percentile:38.64(Physics, Multidisciplinary)

Level structure of the $$^{12}_{Lambda}$$C hypernucleus was precisely determined by means of $$gamma$$-ray spectroscopy. We identified four $$gamma$$-ray transitions via the $$^{12}$$C$$(pi^{+},K^{+}gamma)$$ reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet $$(2^{-}, 1^{-}_{1})$$ was measured to be $$161.5pm0.3$$(stat)$$pm0.3$$ (syst)keV from the direct $$M1$$ transition. Excitation energies of the $$1^{-}_{2}$$ and $$1^{-}_{3}$$ states were measured to be $$2832pm3pm4$$, keV and $$6050pm8pm7$$, keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of $$Lambda$$ hypernuclei.

Journal Articles

Study on heat transfer mechanism elucidation during pool nucleate boiling by measuring instantaneous surface temperature distribution with infrared radiation camera

Koizumi, Yasuo; Takahashi, Kazuki*; Uesawa, Shinichiro; Yoshida, Hiroyuki; Takase, Kazuyuki

Dai-52-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu (CD-ROM), P. 2, 2015/06

Pool nucleate boiling heat transfer experiments were performed for water at 0.101 MPa to examine the elementary process of the nucleate boiling. The copper printed circuit board of a 1.57 mm thick bakelite plate coated with a 0.035 mm thick copper membrane was used for a heat transfer surface. The size of the heat transfer surface was 10 mm $$times$$ 10 mm. direct current was supplied to it to heat it up. The bakelite plate of the backside of the copper layer was taken by 7 mm $$times$$ 10 mm. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. The time and the space resolution of the infrared cameras used in experiments were 120 Hz and 0.315 mm $$times$$ 0.315 mm, respectively. Surface temperatures just before the burn-out measured with 120 Hz suggest that the surface temperature was steadily low at a large part of the heat transfer surface. A small hot-dry area came out at the critical heat flux condition. Then, this small hot-dry area iterated to expand and shrink and gradually grew. Other area was still wetted and kept at low temperature. Eventually the small hot-dry area started to grow continuously and a whole part of the heat transfer surface became hot-dry to reach the physical burn-out. The heat transfer surface was divided into two large areas; the hot-dry area and the low-temperature wetted area until the physical burn-out. The local surface heat flux variation derived from measured surface temperature variation clearly illustrated that the boundary between the dried area and the wetted area moved back and forth and the dried arear gradually grew to reach physical bourn-out at the critical heat flux condition.

Journal Articles

Study on heat transfer surface temperature variation during pool nucleate boiling by measuring instantaneous surface temperature distribution with infrared radiation camera

Koizumi, Yasuo; Takahashi, Kazuki*; Uesawa, Shinichiro; Yoshida, Hiroyuki; Takase, Kazuyuki

Proceedings of 9th International Conference on Boiling and Condensation Heat Transfer (Boiling & Condensation 2015) (DVD-ROM), 10 Pages, 2015/04

Pool nucleate boiling heat transfer experiments were performed for water at 0.101 MPa to examine the elementary process of the nucleate boiling. The copper printed circuit board of a 1.57 mm thick Bakelite plate coated with a 0.035 mm thick copper membrane was used for a heat transfer surface. The size of the heat transfer surface was 10 mm $$times$$ 10 mm. Direct current was supplied to it to heat it up. The Bakelite plate of the backside of the copper layer was taken by 7 mm $$times$$ 10 mm. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. The time and the space resolution of the infrared cameras used in experiments were 120 Hz and 0.315 mm $$times$$ 0.315 mm, respectively. Surface temperatures just before the burn-out measured with 120 Hz suggest that the surface temperature was steadily low at a large part of the heat transfer surface. A small hot-dry area came out at the critical heat flux condition. Then, this small hot-dry area iterated to expand and shrink and gradually grew. Other area was still wetted and kept at low temperature. Eventually the small hot-dry area started to grow continuously and a whole part of the heat transfer surface became hot-dry to reach the physical burn-out. The heat transfer surface was divided into two large areas; the hot-dry area and the low-temperature-wetted area until the physical burn-out. The local surface heat flux variation derived from measured surface temperature variation clearly illustrated that the boundary between the dried area and the wetted area moved back and forth and the dried arear gradually grew to reach physical bourn-out at the critical heat flux condition.

Journal Articles

Recovery of scandium from hot spring water with graft adsorbent containing phosphoric groups

Hoshina, Hiroyuki; Kasai, Noboru; Amada, Haruyo; Takahashi, Makikatsu*; Tanaka, Kazuya*; Seko, Noriaki

Nippon Ion Kokan Gakkai-Shi, 25(4), p.248 - 251, 2014/11

Journal Articles

A New eco-friendly synthesis method for arsenic adsorbent

Amada, Haruyo; Takahashi, Makikatsu*; Hoshina, Hiroyuki; Seko, Noriaki

Nippon Ion Kokan Gakkai-Shi, 25(4), p.109 - 113, 2014/11

Journal Articles

Present state of TEM-SXES analysis and its application to SEM aiming chemical analysis of bulk materials

Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; et al.

Microscopy and Microanalysis, 20(Suppl.3), p.682 - 683, 2014/08

X-rays originate form electronic transitions from valence bands (VB, bonding electron states) to inner-shell electron levels inform us energy states of bonding electrons. We have developed the SXES spectrometers attaching to TEM, EPMA, and SEM. A spectrometer has an energy range of 50-4000 eV by using four varied-line-spacing gratings. Applications of TEM-SXES instrument to C$$_{60}$$ have revealed characteristic energy distribution of bonding electrons. Carbon K-emission spectra of C $$_{60}$$ crystals showed that both the peak structures in $$pi$$- and $$sigma$$-bands and the characteristic dip structure between the $$pi$$- and $$sigma$$-bonding states in monomer-C$$_{60}$$ disappear in the most polymerized-C$$_{60}$$ crystals. Bulk specimens were examined by applying SXES to a SEM. Al L-emission spectra of intermetallic compounds of Al$$_{2}$$Au, AlCo, and aluminum showed different intensity distributions due to different band structures originating from different crystal structures.

Journal Articles

Exciting possibilities of soft X-ray emission spectroscopy as chemical state analysis in EPMA and FESEM

Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Terauchi, Masami*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Hasegawa, Noboru; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 20(Suppl.3), p.684 - 685, 2014/08

A novel wavelength dispersive soft X-ray emission spectrometer (SXES) having a X-ray energy range of 50-210 eV has been developed. One feature is that the SXES is parallel detection of the signals so that it can be used like a conventional energy dispersive spectrometer. The other is a high energy resolution, which is about 0.2 eV at Al-L comparable to those revealed by XPS and EELS. These features enable us to obtain meaningful information about chemical bonding in various bulk samples. The SXES can detect Li-K emission spectrum. In the case of an anode electrode of a lithium ion battery (LIB), two types of lithium peaks are observed: one lower energy peak at 50 eV and the other higher energy peak at 54 eV. It was found that the former peak corresponds to the amount of charging, whereas the latter corresponds to the metallic state of lithium.

Journal Articles

Chemical state information of bulk specimens obtained by SEM-based soft-X-ray emission spectrometry

Terauchi, Masami*; Koshiya, Shogo*; Sato, Futami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; et al.

Microscopy and Microanalysis, 20(3), p.692 - 697, 2014/06

 Times Cited Count:11 Percentile:21.61(Materials Science, Multidisciplinary)

Electron beam induced soft-X-ray emission spectroscopy (SXES) by using a grating spectrometer has been introduced to a conventional scanning electron microscope (SEM) for characterizing desired specimen areas of bulk materials. The spectrometer was designed as a grazing-incidence flat-field optics by using aberration corrected (varied-line-spacing) gratings and a multi-channel-plate detector combined with a charge-coupled-device camera, which has already applied for a transmission electron microscope. The best resolution was confirmed as 0.13 eV at Mg L-emission (50 eV), which value is comparable to that of recent dedicated electron energy-loss spectroscopy instruments. This SXES-SEM instrument presents density of states of simple metals of bulk Mg and Li. Apparent band structure effects have been observed in Si L-emission of Si-wafer, P L-emission of GaP-wafer, and Al L-emissions of intermetallic compounds of AlCo, AlPd, Al$$_{2}$$Pt, and Al$$_{2}$$Au.

Journal Articles

First flight demonstration of glass-type space solar sheet

Shimazaki, Kazunori*; Kobayashi, Yuki*; Takahashi, Masato*; Imaizumi, Mitsuru*; Murashima, Mio*; Takahashi, Yu*; Toyota, Hiroyuki*; Kukita, Akio*; Oshima, Takeshi; Sato, Shinichiro; et al.

Proceedings of 40th IEEE Photovoltaic Specialists Conference (PVSC-40) (CD-ROM), p.2149 - 2154, 2014/06

The electrical performance of a glass-type space solar sheet (G-SSS) was demonstrated in space. G-SSS comprises InGaP/GaAs dual-junction and InGaP/GaAs/InGaAs triplejunction solar cells. It is lightweight solar generation sheet, less than 0.5 mm thick. It is mounted on the "HISAKI" (SPRINT-A) small scientific satellite, which was launched on September 14, 2013. The initial flight data were successfully acquired and this flight demonstration was a world-first experiment for G-SSS using III-V multi-junction thin-film solar cells. The cells demonstrated superior performance and the electrical outputs matched the flight prediction.

352 (Records 1-20 displayed on this page)