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| 1 | Sm-doped CsBr crystal as a new radio-photoluminescence (RPL) material显示文摘Radio-photoluminescence(RPL) is a phenomenon seen in luminescent materials in which the appearance of new photoluminescence(PL) emission is induced by an incident ionizing radiation such as X-rays; and the signal is stable even after the irradiation and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in radiation measurements. The distinct advantage of RPL over the conventional thermally- or photo-stimulated luminescence(abbreviated as TSL or PSL) dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple time without signal fading. In this work, we discovered that CsB r:Sm showed an RPL phenomenon by X-ray irradiation, and we characterized this new material as an RPL detector. While the sample showed PL emissions mainly in the visible range, after an X-ray irradiation additional emissions could be observed in the red to near-infrared range around 650–850 nm and 900–1000 nm and longer. The RPL response was fairly stable overall, but very interestingly the 650–850 nm signal slightly increased while the 900–1000 nm decreased during PL readout. The dynamic range was confirmed over 1–10~4 mG y with linear response. | Go Okada Yutaka Fujimoto Hironori Tanaka Safa Kasap Takayuki Yanagida | 2016 | Journal of Rare Earths2016，34，8： | 2 |
| 2 | Photoluminescence, scintillation and thermally-stimulated luminescence properties of Tb-doped 12CaO·7Al2O3 single crystals grown by FZ method显示文摘Tb-doped 12CaO·7Al_2O_3(Tb:C12A7) crystals were synthesized by the floating zone(FZ) method and the photoluminescence(PL), scintillation and thermally-stimulated luminescence(TSL) properties were investigated. The photoluminescence(PL) emission spectra and PL decay time profiles were investigated by using Quantaurus-tau(Hamamatsu). The scintillation spectra and decay time profiles were measured by using our laboratory-constructed set-up under X-ray irradiation. Finally, TSL glow curve was measured by using Nanogray TL-2000 with the heating rate of 1 °C/s. In PL and scintillation, emission peaks were observed at 493, 543, 587 and 620 nm due to the 4f-4f transitions of Tb3^+. Decay time constants of the emission by PL and scintillation appeared to be different, and the measured values were approximately 2.4 and 1.9 ms, respectively. After X-ray irradiations, the 0.5%(all Tb contents in this paper are in mole fraction) and 1.0% Tb-doped samples showed a single intense and broad glow peak around 100 oC while 1.2%–1.5% Tb-doped samples showed notable additional peak around 250 oC. | Narumi Kumamoto Daisuke Nakauchi Takumi Kato Go Okada Noriaki Kawaguchi Takayuki Yanagida | 2017 | Journal of Rare Earths2017，35，10： | 1 |
| 3 | Optical and scintillation properties of Nd-doped SrAl2O4 crystals显示文摘Nd-doped SrAl_2O_4(Nd:SrAl_2O_4) crystals were prepared by a floating zone(FZ) method with different dopant concentrations. The photoluminescence(PL) measurements under visible light excitations confirmed strong near infrared(NIR) emissions around 890 nm, which is due to the 4f-4f transitions of Nd3+, and the decay time constants were 300–400 μs. Furthermore, VUV excitations revealed two broad emissions around 250–450 and 500–700 nm, which were attributed to self-trapped excitons(STEs) perturbed by Nd3+. Moreover, the X-ray induced scintillation spectra showed some small peaks at around 380 nm in addition to NIR emissions at 1064 nm similarly seen in PL. The former scintillation decay time constants were 30–40 μs. In the undoped sample, these emissions mentioned above were not present but a weak broad emission around 450 nm appeared. In thermally stimulated luminescence(TSL) after X-ray irradiation, strong TSL glow peaks were observed in the Nd-doped samples at around 100 and 250 oC. | Daisuke Nakauchi Go Okada Masanori Koshimizu Takayuki Yanagida | 2016 | Journal of Rare Earths2016，34，8： | 1 |
| 4 | Scintillation and optical properties of Ce-doped YAGG transparent ceramics显示文摘We investigated photoluminescence(PL) and scintillation properties of Ce^(3+)-doped Y_3Al_2Ga_3O_(12)(Ce:YAGG) transparent ceramics synthesized by vacuum sintering with different Ce^(3+) concentrations(mol.%) from 0.3% to 1%(0.3%Ce:YAGG, 0.5%Ce:YAGG, 0.8%Ce:YAGG and 1%Ce:YAGG). The samples were synthesized by the vacuum sintering technique. The obtained samples showed a very strong and broad PL emission by the 5d1-4f transition of Ce^(3+) in the wavelength range from 470 to 600 nm. The PL decay profiles were approximated by a single exponential decay function with the time constants of around 33–39 ns. Furthermore, the scintillation spectra induced by X-rays showed similar features with those observed in PL. The scintillation decay time profiles followed a second-order exponential decay function. The fast component group(ranged 35–42 ns) were dominantly contributed by the 5d_1-4f transition of Ce^(3+). The pulse height spectra utilizing the latter emissions showed a clear photoabsorption peak. Among those samples tested, 0.5%Ce:YAGG sample showed the highest scintillation light yield of 21,400 ph/MeV under ^(137)Cs γ-ray irradiation. | Masaki Mori Jian Xu Go Okada Takayuki Yanagida Jumpei Ueda Setsuhisa Tanabe | 2016 | Journal of Rare Earths2016，34，8： | 1 |
| 5 | Brain activity during expectancy of emotional stimuli:an fMRI study显示文摘 | Ueda Kazutake Okamoto Yasumasa Okada GO | 2003 | Neuroreport2003，14，1： | 1 |
| 6 | Personality traits and the amplitude of spontaneous low-frequency oscillations during resting state显示文摘 | Yoshihiko Kunisato Yasumasa Okamoto Go Okada Shiori Aoyama Yoshiko Nishiyama Keiichi Onoda Shigeto Yamawaki | 2011 | Neuroscience Letters2011，，2： | 1 |
| 7 | Meta-analysis identifies multiple loci associated with kidney function-related traits in east Asian populations显示文摘 | Okada Y Sim X Go MJ | 2012 | Nat Genet2012，44，8： | 1 |
| 8 | Solar power sail mission of OKEANOS显示文摘The solar power sail is an original Japanese concept in which electric power is generated by thin-film solar cells attached on the solar sail membrane.Japan Aerospace Exploration Agency(JAXA)successfully demonstrated the world’s first solar power sail technology through IKAROS(Interplanetary Kite-craft Accelerated by Radiation of the Sun)mission in 2010.IKAROS demonstrated photon propulsion and power generation using thin-film solar cells during its interplanetary cruise.Scaled up,solar power sails can generate enough power to drive high specific impulse ion thrusters in the outer planetary region.With this concept,we propose a landing or sample return mission to directly explore a Jupiter Trojan asteroid using solar power sail-craft OKEANOS(Oversize Kite-craft for Exploration and AstroNautics in the Outer Solar System).After rendezvousing with a Trojan asteroid,a lander separates from OKEANOS to collect samples,and perform in-situ analyses in three proposed mission sequences,including sending samples back to Earth.This paper proposes a system design for OKEANOS and includes analyses of the latest mission. | Osamu Mori Jun Matsumoto Toshihiro Chujo Masanori Matsushita Hideki Kato Takanao Saiki Yuichi Tsuda Jun'ichiro Kawaguchi Fuyuto Terui Yuya Mimasu Go Ono Naoko Ogawa Yuki Takao Yuki Kubo Kaoru Ohashi Ahmed Kiyoshi Sugihara Tatsuaki Okada Takahiro Iwata Hajime Yano | 2020 | Astrodynamics2020，4，3： | 0 |
| 9 | Hayabusa2’s station-keeping operation in the proximity of the asteroid Ryugu显示文摘The Japanese interplanetary probe Hayabusa2 was launched on December 3,2014 and the probe arrived at the vicinity of asteroid 162173 Ryugu on June 27,2018.During its 1.4 years of asteroid proximity phase,the probe successfully accomplished numbers of record-breaking achievements including two touchdowns and one artificial cratering experiment,which are highly expected to have secured surface and subsurface samples from the asteroid inside its sample container for the first time in history.The Hayabusa2 spacecraft was designed not to orbit but to hover above the asteroid along the sub Earth line.This orbital and geometrical configuration allows the spacecraft to utilize its high-gain antennas for telecommunication with the ground station on Earth while pointing its scientific observation and navigation sensors at the asteroid.This paper focuses on the regular station-keeping operation of Hayabusa2,which is called“home position”(HP)-keeping operation.First,together with the spacecraft design,an operation scheme called HP navigation(HPNAV),which includes a daily trajectory control and scientific observations as regular activities,is introduced.Following the description on the guidance,navigation,and control design as well as the framework of optical and radiometric navigation,the results of the HP-keeping operation including trajectory estimation and delta-V planning during the entire asteroid proximity phase are summarized and evaluated as a first report.Consequently,this paper states that the HP.keeping operation in the framework of HPNAV had succeeded without critical incidents,and the number of trajectory control delta-V was planned fficiently throughout the period. | Yuto Takei Takanao Saiki Yukio Yamamoto Yuya Mimasu Hiroshi Takeuchi Hitoshi Ikeda Naoko Ogawa Fuyuto Terui Go Ono Kent Yoshikawa Tadateru Takahashi Hirotaka Sawada Chikako Hirose Shota Kikuchi Atsushi Fuji Takahiro Iwata Satoru Nakazawa Masahiko Hayakawa Ryudo Tsukizaki Satoshi Tanaka Masanori Matsushita Osamu Mori Daiki Koda Takanobu Shimada Masanobu Ozaki Masanao Abe Satoshi Hosoda Tatsuaki Okada Hajime Yano Takaaki Kato Seiji Yasuda Kota Matsushima Tetsuya Masuda Makoto Yoshikawa Yuichi Tsuda | 2020 | Astrodynamics2020，4，4： | 0 |
| 10 | Photoluminescence and radioluminescence properties of (Gd8Ca2)(SiO4)6O2 crystals with different concentrations of Ce显示文摘(Gd_8 Ca_2)(SiO_4)_6 O_2 apatite crystals doped with different concentrations of Ce were synthesized by the Floating Zone(FZ) method, and we have evaluated the photoluminescence(PL) and radio luminescence(RL) properties. In PL, an emission band appeared around 400 nm under excitation at 300 nm due to the5 d-4 f transitions of Ce3+. The PL decay curves were approximated by a second-order exponential decay function, and the derived decay time constants ranged around 20-25 ns and 40-480 ns. Similar emission was observed in RL, but the decay time constants were much longer than those in PL. The RL afterglow was the lowest in the 1.0% Ce-doped sample. The 1.0% and 2.0% Ce-doped samples showed a full-energy peak in the pulse height spectrum measured under ^(241) Am 5.5 MeV α-ray irradiation, and the absolute scintillation light yields were estimated to be around 55 and 36 ph/5.5 MeV-a, respectively. | Takuya Igashira Masaki Mori Go Okada Noriaki Kawaguchi Takayuki Yanagida | 2017 | Journal of Rare Earths2017，35，11： | 0 |
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