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Journal Articles

Degassing behavior of noble gases from groundwater during groundwater sampling

Nakata, Kotaro*; Hasegawa, Takuma*; Solomon, D. K.*; Miyakawa, Kazuya; Tomioka, Yuichi*; Ota, Tomoko*; Matsumoto, Takuya*; Hama, Katsuhiro; Iwatsuki, Teruki; Ono, Masahiko*; et al.

Applied Geochemistry, 104, p.60 - 70, 2019/05

 Times Cited Count:0 Percentile:100(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:79 Percentile:0.09(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

An Inter-laboratory comparison study on $$^{14}$$C measurements between two AMS laboratories of Nagoya University and JAEA Mutsu

Nakamura, Toshio*; Tanaka, Takayuki; Kabuto, Shoji; Ota, Tomoko*

Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 21, p.159 - 165, 2010/03

An inter-laboratory comparison of $$^{14}$$C dating studies with AMS were performed between Nagoya University and JAEA. Two kinds of archeological samples used for the intercomparison were offered from the Education Board of Nirasaki city. One part of them was a charred rice sample with known historical age, which was collected from the ruin of Shimpu-Jo castle remains. The rice was charred when the castle was burnt in 1582, when the castle was abandoned by Katsuyori Takeda during the battle against the combined military forces of Oda and Tokugawa families. The other samples were charred pyrenes of peach and nutshells of Japanese walnut collected from the Shukujiri-Daini-Iseki archeological site. The results from the two AMS laboratories were quite consistent within statistical uncertainties. In addition, calibrated $$^{14}$$C ages for the charred rice samples were also consistent with the historical age when the Shimpu-Jo castle was burnt down.

Journal Articles

Stoichiometric study of the dielectric and magnetic properties in charge frustrated system LuFe$$_{2}$$O$$_{4}$$

Michiuchi, Takamasa*; Yokota, Yusuke*; Komatsu, Takuma*; Hayakawa, Hironori*; Kuroda, Tomoko*; Maeda, Daisuke*; Matsuo, Yoji*; Mori, Shigeo*; Yoshii, Kenji; Hanasaki, Noriaki*; et al.

Ferroelectrics, 378(1), p.175 - 180, 2009/00

 Times Cited Count:17 Percentile:37.69(Materials Science, Multidisciplinary)

We have synthesized the samples of LuFe$$_{2}$$O$$_{4}$$, which shows the ferroelectricity due to charge ordering of Fe ions, under several different reducing conditions using a CO$$_{2}$$-CO flow. The reducing condition was changed by changing a flow ratio of CO$$_{2}$$ and CO. It was found that the flow ratio of CO$$_{2}$$/CO of about 5 provided the sample with the highest magnetic transition temperature of 240-250 K. This sample showed the dielectric constant of 10000 at room temperature. The imaginary part of the dielectric response offered the activation energy of 0.4-0.5 eV, which is slightly larger than that reported previously (about 0.3 eV). We will perform further investigation of the physical properties of this sample to clarify full details and their origin of LuFe$$_{2}$$O$$_{4}$$.

Journal Articles

Investigation on extraction methods of environmental iodine

Kubota, Takumi*; Nakano, Tomoko*; Amano, Hikaru; Suzuki, Takashi; Mahara, Yasunori*

JAEA-Conf 2008-003, p.36 - 39, 2008/04

In analysis of environmental iodine, samples containing low I-129 and low iodine amount are subject to contamination from reagents and apparatus. We measured the isotopic ratio of I-129/I-127 in brine that was collected at Mobara in Chiba prefecture and was characterized as having a high iodine concentration and a low isotopic ratio. The results, however, showed high isotopic ratios. We suspected that the contamination was caused by using halogen containing reagents because the samples treated with Cl-form anion exchange resin in iodine extraction process were strongly contaminated. In this study, we have conducted halogen-free extraction processes such as ion exchange and solvent extraction whose recovery has been investigated with $$gamma$$ spectrometry of I-126 produced through photonuclear reaction with the KURRI LINAC. The total iodine recovery through ion exchange with NO$$_{3}$$-form anion exchange resin and solvent extraction with dodecane was more than 80%.

Journal Articles

Evidence for a hard gap and Wigner lattice in heavily boron-doped synthetic diamond

Sudo, Tomoko*; Ohashi, Kazutoshi*; Sato, Toshimaro*; Ota, Eiji*; Okayasu, Satoru; Sugai, Hiroyuki

Physical Review B, 71(4), p.045211_1 - 045211_7, 2005/01

 Times Cited Count:1 Percentile:91.96(Materials Science, Multidisciplinary)

We have measured low frequency generation-recombination noise (g-r moise) spectra of a heavily boro-doped diamond crystal over the temperature range 20-300 K. The experimental results show that there are two peaks in the g-r noise spectrum at 120 K and 67 K, respectively. The 120 K peak corresponds to experimental evidence for the existence of hard gap having width of 10.4 meV. We interpret the 67 K peak as evidence for Wigner lattice formation whose gap width is 5.8 meV.

Journal Articles

Vanadium uptake and an effect of vanadium treatment on $$^{18}$$F-labeled water movement in a cowpea plant by positron emitting tracer imaging system (PETIS)

Furukawa, Jun*; Yokota, Harumi*; Tanoi, Keitaro*; Ueoka, Shiori*; Matsuhashi, Shimpei; Ishioka, Noriko; Watanabe, Satoshi; Uchida, Hiroshi*; Tsuji, Atsunori*; Ito, Takehito*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 249(2), p.495 - 498, 2001/08

 Times Cited Count:10 Percentile:38.05(Chemistry, Analytical)

We present real time Vanadate (V$$^{5+}$$) uptake imaging in a cowpea plant by Positron Emitting Tracer Imaging System (PETIS). Vanadium-48 was produced by bombarding a Sc foil target with 50 MeV $$alpha$$-particles at Takasaki Ion accelerators for Advanced Radiation Application (TIARA) AVF cyclotron. Then $$^{48}$$V was added to the culture solution to investigate the V distribution in a cowpea plant. The real time uptake of the $$^{48}$$V was monitored by PETIS. We measured the distribution of $$^{48}$$V in a whole plant after 3, 6 and 20 hours of V treatment by Bio-imaging Analyzer System (BAS). After the 20 hour treatment, vanadate was detected at the up-ground part of the plant. To know the effect of V uptake on plant activity, $$^{18}$$F-labeled water uptake was analyzed by PETIS. When a cowpea plant was treated with V for 20 hours before $$^{18}$$F-labeled water uptake experiment, the total amount of $$^{18}$$F-labeled water absorption was drastically desreased. Results suggest the inhibition of water uptake was mainly caused by the vanadate already moved to the up-ground part of the plant.

Journal Articles

$$^{18}$$F used as tracer to study water uptake and transport imaging of a cowpea plant

Nakanishi, Tomoko*; Tanoi, Keitaro*; Yokota, Harumi*; Kang, D.-J.*; Ishii, Ryuichi*; Ishioka, Noriko; Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; Matsuhashi, Shimpei; et al.

Journal of Radioanalytical and Nuclear Chemistry, 249(2), p.503 - 507, 2001/08

We present the water uptake ability of cowpea ($$it {Vigna unguliculata Walp.}$$) which has been regarded as one of the most drought resistant species among the pulse crops. It has been suggested that in the lower part of the stem, parenchymatous tissue for storing water had been developed for the function of deought resistance. We confirmed that in this tissue, water amount was high compared to the other stems by neutron radiography. Then the water uptake manner was measured by positron emitting tracer imaging system (PETIS) using $$^{18}$$F labeled water produced by a cyclotron. Comparing the water uptake manner of cowpea plant with that of common bean, cowpea plant was found to maintain high water uptake activity after drying treatment, suggesting the high drought resistant character.

Journal Articles

Comparison of $$^{15}$$O-labeled and $$^{18}$$F-labeled water uptake in a soybean plant by PETIS (Positron Emitting Tracer Imaging System)

Nakanishi, Tomoko*; Yokota, Harumi*; Tanoi, Keitaro*; Ikeue, Natsuko*; Okuni, Yoko*; Furukawa, Jun*; Ishioka, Noriko; Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; et al.

Radioisotopes, 50(6), p.265 - 269, 2001/06

$$^{15}$$O-Labeled and $$^{18}$$F-Labeled water uptake manner in a soybean plant was compared by PETIS (Positron Emitting Tracer Imaging System). $$^{15}$$O-Labeled water (half-life: 2 min) and $$^{18}$$F-Labeled water (half-life: 110 min) were produced by a cyclotron by $$^{14}$$N(d,n)$$^{15}$$O and $$^{16}$$O($$alpha$$,pn)$$^{18}$$F reactions, respectively. A root of a soybean plant was cut off and each labeled water was supplied from the basal part of the plant. The gamma-rays emitted from the sample was measured by a BGO counter with a detection area of 5 cm$$times$$15 cm. The radioactivity from each stem was accumlated every 15 s till 20 min. It was found that $$^{18}$$F-labeled water was taken up much faster than $$^{15}$$O-labeled water, suggesting that in $$^{18}$$F-labeled water, fluorine was moved in the form of $$^{18}$$F-ion. When BAS image of $$^{15}$$O-labeled water in a plant after 5 min and 10 min of water supply was taken, it was found that the labeled water was observed only in the lowest internode, between a root and the first leaves.

Journal Articles

Deep drawing process of Nb for superconducting cavity

Ohara, Kazuhiro*; Kusano, Joichi; Inoue, Hitoshi*; Takaishi, Kazutoshi*; Yamada, Takayuki*; Ouchi, Nobuo; Ota, Tomoko*

Dai-50-Kai Sosei Kako Rengo Koenkai Koen Rombunshu, p.199 - 200, 1999/10

no abstracts in English

Oral presentation

Investigation on extraction methods of environmental iodine using I-126

Kubota, Takumi*; Nakano, Tomoko*; Amano, Hikaru; Suzuki, Takashi; Mahara, Yasunori*

no journal, , 

no abstracts in English

Oral presentation

Study of groundwater residence time in Mizunami Underground Research Laboratory

Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki

no journal, , 

Groundwater dating using $$^{14}$$C, $$^{4}$$He, noble gas method was conducted in Mizunami Underground Research laboratory. The availability of degassing method for $$^{14}$$, flux estimation method for He were examined. It was identified that the groundwater have been derived in glacial age. The integration of distinct dating method is available to estimate precise age of groundwater.

Oral presentation

CRIEPI-JAEA collaboration study on mass transport by groundwater in and around the Mizunami Underground Research Laboratory

Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki

no journal, , 

no abstracts in English

Oral presentation

Groundwater dating conducted in Mizunami Underground Research Laboratory

Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki

no journal, , 

Groundwater dating was conducted to Mizunami Underground Research Laboratory (MIU). $$^{14}$$C age and $$^{4}$$He age were estimated about 20,000 years around MIU. The estimation of noble gas temperature is also conducted. The estimated recharge temperature is around 6$$^{circ}$$C. This temperature is about 9$$^{circ}$$C cooler than present annual average temperature, which agree with estimation of modern analog method conducted near MIU.

Oral presentation

Multiple groundwater dating conducted at Mizunami URL

Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Okamoto, Shunichi*; Hama, Katsuhiro; Watanabe, Yusuke; Iwatsuki, Teruki

no journal, , 

no abstracts in English

15 (Records 1-15 displayed on this page)
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