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Journal Articles

Flow filtration/adsorption and simultaneous monitoring technologies of radiocesium $$^{137}$$Cs in river water

Enomoto, Kazuyuki*; Hoshina, Hiroyuki*; Kasai, Noboru*; Kurita, Keisuke; Ueki, Yuji*; Nagao, Yuto*; Yin, Y.-G.*; Suzui, Nobuo*; Kawachi, Naoki*; Seko, Noriaki*

Chemical Engineering Journal, 460, p.141696_1 - 141696_9, 2023/03

 Times Cited Count:1 Percentile:53.63(Engineering, Environmental)

This study develops a method that combines a radiation-grafting fibrous Cs-adsorbent filter of ammonium molybdophosphate (AMP) and a Ce:Gd$$_3$$Al$$_2$$Ga$$_3$$O$$_{12}$$ scintillator based $$gamma$$-ray detector for in situ measurements of the activity concentrations of $$^{137}$$Cs in a continuous water flow.

Journal Articles

Noninvasive imaging of hollow structures and gas movement revealed the gas partial-pressure-gradient-driven long-distance gas movement in the aerenchyma along the leaf blade to submerged organs in rice

Yin, Y.-G.*; Mori, Yoshinao*; Suzui, Nobuo*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Miyoshi, Yuta*; Nagao, Yuto*; Ashikari, Motoyuki*; Nagai, Keisuke*; Kawachi, Naoki*

New Phytologist, 232(5), p.1974 - 1984, 2021/12

 Times Cited Count:7 Percentile:66.93(Plant Sciences)

Rice ($$Oryza sativa$$) plants have porous or hollow organs consisting of aerenchyma, which is presumed to function as a low-resistance diffusion pathway for air to travel from the foliage above the water to submerged organs. However, gas movement in rice plants has yet to be visualized in real time. In this study involving partially submerged rice plants, the leaves emerging from the water were fed nitrogen-13-labeled nitrogen ([$$^{13}$$N]N$$_2$$) tracer gas, and the gas movement downward along the leaf blade, leaf sheath, and internode over time was monitored.

Journal Articles

Effect of irradiation on corrosion behavior of 316L steel in lead-bismuth eutectic with different oxygen concentrations

Okubo, Nariaki; Fujimura, Yuki; Tomobe, Masakatsu*

Quantum Beam Science (Internet), 5(3), p.27_1 - 27_9, 2021/09

In an accelerator driven system (ADS), the beam window material of the spallation neutron target is heavily irradiated under severe conditions. Displacement damage and corrosion occur simultaneously because of high-energy neutron and/or proton irradiation in the lead-bismuth flow. The materials used in ADSs need to be compatible with the liquid metal, which is lead-bismuth eutectic (LBE), to prevent issues such as liquid metal embrittlement (LME) and liquid metal corrosion (LMC). In this study, the LMC behavior after ion irradiation of 316L austenitic steel is considered for self-ion irradiations followed by the corrosion tests. The 316L specimens were irradiated by 10.5 MeV-Fe$$^{3+}$$ ions at temperature of 450$$^{circ}$$C up to 50 displacement per atom (dpa). After the corrosion test at 450$$^{circ}$$C in LBE with low oxygen concentration, the surface of the non-irradiated area was not oxidized but corrosive morphology with pits, whereas the irradiated area was covered by an iron/chromium oxide layer. The surface of the irradiated area was covered by the duplex layers of iron and iron/chromium oxides in the case of higher oxygen concentration in LBE. It is suggested that irradiation can advance oxide layer formation because of enhanced Fe diffusion caused by the residual vacancies in 316L steel.

Journal Articles

Non-invasive $$^{11}$$C-imaging revealed the spatiotemporal variability in the translocation of photosynthates into strawberry fruits in response to increasing daylight integrals at leaf surface

Miyoshi, Yuta*; Hidaka, Kota*; Yin, Y.-G.*; Suzui, Nobuo*; Kurita, Keisuke; Kawachi, Naoki*

Frontiers in Plant Science (Internet), 12, p.688887_1 - 688887_14, 2021/07

 Times Cited Count:10 Percentile:78.16(Plant Sciences)

In this study, $$^{11}$$C-photosynthate translocation into strawberry fruits in individual plants was visualized non-invasively and repeatedly using a positron emission tracer imaging system (PETIS) to assess the spatiotemporal variability in the translocation dynamics in response to increasing daylight integrals. This is the first study to use $$^{11}$$C-radioisotopes to clarify the spatiotemporal variability in photosynthate translocation from source leaves to individual sink fruits in vivo in response to increasing daylight integrals at a high spatiotemporal resolution.

Journal Articles

Application of OpenPET as 3-D imaging device of carbon distribution in fruit

Kurita, Keisuke; Miyoshi, Yuta*; Nagao, Yuto*; Yamaguchi, Mitsutaka*; Suzui, Nobuo*; Yin, Y.-G.*; Ishii, Satomi*; Kawachi, Naoki*; Hidaka, Kota*; Yoshida, Eiji*; et al.

QST-M-29; QST Takasaki Annual Report 2019, P. 106, 2021/03

Journal Articles

Visualising spatio-temporal distributions of assimilated carbon translocation and release in root systems of leguminous plants

Yin, Y.-G.*; Suzui, Nobuo*; Kurita, Keisuke; Miyoshi, Yuta*; Unno, Yusuke*; Fujimaki, Shu*; Nakamura, Takuji*; Shinano, Takuro*; Kawachi, Naoki*

Scientific Reports (Internet), 10, p.8446_1 - 8446_11, 2020/06

 Times Cited Count:10 Percentile:60.52(Multidisciplinary Sciences)

The release of rhizodeposits differs depending on the root position and is closely related to the assimilated carbon (C) supply. Therefore, quantifying the C partitioning over a short period may provide crucial information for clarifying root-soil carbon metabolism. A non-invasive method for visualising the translocation of recently assimilated C into the root system inside the rhizobox was established using $$^{11}$$CO$$_{2}$$ labelling and the positron-emitting tracer imaging system. The spatial distribution of recent $$^{11}$$C-photoassimilates translocated and released in the root system and soil were visualised for white lupin ($$Lupinus albus$$) and soybean ($$Glycine max$$). Our method enabled the quantification of the spatial C allocations in roots and soil, which may help to elucidate the relationship between C metabolism and nutrient cycling at specific locations of the root-soil system in response to environmental conditions over relatively short periods.

Journal Articles

Control of the size of etchable ion tracks in PVDF; Irradiation in an oxygen atmosphere and with fullerene C$$_{60}$$

Kitamura, Akane; Yamaki, Tetsuya*; Yuri, Yosuke*; Koshikawa, Hiroshi*; Sawada, Shinichi*; Yuyama, Takahiro*; Usui, Aya; Chiba, Atsuya*

Nuclear Instruments and Methods in Physics Research B, 460, p.254 - 258, 2019/12

 Times Cited Count:2 Percentile:23.44(Instruments & Instrumentation)

Poly(vinylidene-fluoride) (PVDF) film is suitable for investigation of the size of etchable ion tracks because we can clearly judge the finish of the track etching and the surrounding bulk area remains due to the high chemical stability. Thereby we can measure the radius of ion tracks of each ion. In this study, we focused on two irradiation conditions for controlling the size of etchable ion tracks of PVDF films. One was irradiation in an oxygen atmosphere and the other was a fullerene (C$$_{60}$$$$^{+}$$) cluster beam irradiation. SEM observation showed that the size of pores became larger by irradiation in an oxygen atmosphere. It was found that the oxidation of ion tracks widened the size of etchable ion tracks. The C$$_{60}$$$$^{+}$$ irradiation caused larger etchable tracks on the PVDF surface. The result could represent the effect of local and simultaneous collisions by the swift aggregated ions.

Journal Articles

On-line rapid purification of [$$^{13}$$N]N$$_2$$ gas for visualization of nitrogen fixation and translocation in nodulated soybean

Yin, Y.-G.*; Ishii, Satomi*; Suzui, Nobuo*; Igura, Masato*; Kurita, Keisuke; Miyoshi, Yuta*; Nagasawa, Naotsugu*; Taguchi, Mitsumasa*; Kawachi, Naoki*

Applied Radiation and Isotopes, 151, p.7 - 12, 2019/09

 Times Cited Count:6 Percentile:56.35(Chemistry, Inorganic & Nuclear)

Accurate analysis of N fixation in leguminous crops requires determination of N utilization within an intact plant$$;$$ however, most approaches require tissue disassembly. We developed a simple and rapid technique to generate high-purity and high-yield [$$^{13}$$N]N$$_2$$ gas and obtained real-time images of N fixation in an intact soybean plant. The purification efficiency was $$sim$$ 81.6% after decay correction.

Journal Articles

Development of cation and anion exchange membranes for saline water concentration using high-energy heavy-ion beams

Sawada, Shinichi*; Yasukawa, Masahiro*; Koshikawa, Hiroshi*; Kitamura, Akane; Higa, Mitsuru*; Yamaki, Tetsuya*

Nihon Kaisui Gakkai-Shi, 73(4), p.208 - 216, 2019/08

For applications to saline water concentration by electrodialysis, we prepared nano-structure-controlled cation and anion exchange membranes (CEMs and AEMs) by a so-called ion-track grafting technique. This new technique involves irradiation of a polymer substrate with an MeV-GeV heavy-ion beam to form the nano-sized cylindrical ion tracks and the graft polymerization only into the ion tracks for the creation of one-dimensional transport pathways. A 25-$$mu$$m-thick poly(ethylene-co-tetrafluoroethylene) film was irradiated with 560 MeV $$^{129}$$Xe or 310 MeV $$^{84}$$Kr. The irradiated films were immersed in grafting solutions of ethyl p-styrenesulfonate (EtSS) and chloromethylstyrene (CMS), and then subjected to the hydrolysis of EtSS units and quaternization of CMS units to prepare CEMs and AEMs, respectively. These CEMs and AEMs showed lower resistance than the commercially-available membranes even at the very low water uptake. This would be due to the signifcantly-effcient transport of ions through the unique one-dimensional highly-connected transport pathways. In the saline water concentration experiment, a pair of our CEM and a commercial AEM or vice versa led to a higher salt concentration in the concentration chamber than did a pair of the commercial membranes. This result demonstrated great applicability of our ion-track-grafted CEMs and AEMs for saline water concentration.

Journal Articles

Development of profile monitors on target for high-intensity proton accelerators

Meigo, Shinichiro; Takei, Hayanori; Matsuda, Hiroki; Yuri, Yosuke*; Yuyama, Takahiro*

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.515 - 519, 2019/07

no abstracts in English

Journal Articles

Micro-PIXE analysis study of ferrite products synthesized from simulated radioactive liquid waste containing chemical hazardous elements

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Nakazawa, Osamu; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-16; QST Takasaki Annual Report 2017, P. 140, 2019/03

no abstracts in English

Journal Articles

Fluoropolymer-based nanostructured membranes created by swift-heavy-ion irradiation and their energy and environmental applications

Yamaki, Tetsuya*; Nuryanthi, N.*; Kitamura, Akane; Koshikawa, Hiroshi*; Sawada, Shinichi*; Voss, K.-O.*; Severin, D.*; Tautmann, C.*

Nuclear Instruments and Methods in Physics Research B, 435, p.162 - 168, 2018/11

 Times Cited Count:8 Percentile:63.44(Instruments & Instrumentation)

We used individual single-ion tracks in fluoropolymers with diameters of tens to hundreds of nanometers; chemical etching and ion-track grafting enabled us to develop ion-track and proton-conductive membranes, respectively. In the ion-track membranes of PVDF, strongly-LET-dependent etching was found, so the pore shape as well as the size was exclusively controlled by the track structures. We performed the ion-track grafting of styrene into ETFE to develop nanostructure-controlled proton exchange membranes (PEMs) for applications in PEM fuel cells. Our ion beam technology to develop fluoropolymer-based nanostructures has the potential to apply in the field of filtration processes and fuel cell devices. This would make it possible to provide new microfiltration technology for water treatment, sterilization, petroleum refining and dairy processing.

Journal Articles

Development of profile monitors on target for high-intensity proton accelerators

Meigo, Shinichiro; Takei, Hayanori; Matsuda, Hiroki; Yuri, Yosuke*; Yuyama, Takahiro*

Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1035 - 1039, 2018/08

no abstracts in English

JAEA Reports

Investigative report on the PVC bag burst in the contamination incident at Plutonium Fuel Research Facility; Radiolysis of organic materials and raising of internal pressure

Cause Investigation Team for the PFRF Contamination Incident

JAEA-Review 2017-038, 83 Pages, 2018/03

JAEA-Review-2017-038.pdf:11.37MB

The contaminated accident occurred at Plutonium Fuel Research Facility on June, 2017. The PVC bag packaging in a fuel storage container burst when a worker opened the lid, and a part of contents (uranium and plutonium) was spattered over the room. In order to clarify the cause of the burst, the Cause Unfolding Team collected information concerning characteristics of the contents from any past records and interview. And then we observed and analyzed the contents in a glove box. We also performed experiments on radiolysis of organic materials, degradation of PVC bag by $$gamma$$ radiation, and PVC bag burst. Based on fault tree analysis, finally we concluded that the main gas generation source was alpha radiolysis of the epoxy resin mixed with the fuel powder. We hope that the calculation procedures for the gas generation and the inner pressure transition described in this report can be useful reference for the management of fuel storage in other facilities.

Journal Articles

Profile monitor on target for spallation neutron source

Meigo, Shinichiro; Matsuda, Hiroki; Takei, Hayanori

Proceedings of 6th International Beam Instrumentation Conference (IBIC 2017) (Internet), p.373 - 376, 2018/03

no abstracts in English

Journal Articles

Application of ferrite process to radioactive waste; Study of ferrite product stability by micro-PIXE analysis

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-8; QST Takasaki Annual Report 2016, P. 61, 2018/03

no abstracts in English

Journal Articles

Fabrication of neutron optical devices using PBW technique

Sakai, Takuro; Iikura, Hiroshi; Yamada, Naoto*; Sato, Takahiro*; Ishii, Yasuyuki*; Uchida, Masaya*

QST-M-8; QST Takasaki Annual Report 2016, P. 140, 2018/03

Journal Articles

Ion track etching of PVDF films irradiated with fast C$$_{60}$$$$^{+}$$ cluster ions

Kitamura, Akane; Yamaki, Tetsuya*; Chiba, Atsuya*; Usui, Aya

QST-M-8; QST Takasaki Annual Report 2016, P. 37, 2018/03

We investigated the track-etched surface of PVDF films irradiated with C$$_{60}$$$$^{+}$$ cluster ions, comparing the data with C$$^{+}$$ monoatomic ions. PVDF films were irradiated with 6 MeV C$$_{60}$$$$^{+}$$ cluster ions. The energy of the each carbon ion is 100 keV/atom; thus, for comparison, the PVDF films were also irradiated with 100 keV C$$^{+}$$ ions. SEM and AFM observation showed that the surface irradiated with C$$_{60}$$$$^{+}$$ cluster ions apparently possessed flat-bottomed pores with an average diameter and depth of approximately 400 and 250 nm, respectively. On the other hand, track-etched pores were also formed on the surface irradiated with C$$^{+}$$ ions, but their morphology was irregular or obscure. In the irradiation with the C$$_{60}$$$$^{+}$$ cluster ions, the surface diameter of track-etched pores increased with increasing the etching time. The tracks of the 100 keV C$$^{+}$$ ions seemed to be hardly developed by the etching when the time. In conclusion, the C$$_{60}$$$$^{+}$$ cluster ions irradiation caused a large size of etchable tracks on the PVDF surface. The result could represent the effect of local and simultaneous collision by the aggregated ions.

Journal Articles

Preparation of nano-structure controlled ion-exchange membranes by ion beams and their application to seawater concentration

Yamaki, Tetsuya*; Goto, Mitsuaki*; Sawada, Shinichi*; Koshikawa, Hiroshi*; Kitamura, Akane; Higa, Mitsuru*

QST-M-8; QST Takasaki Annual Report 2016, P. 35, 2018/03

We prepared ion exchange membranes by a heavy-ion-track grafting method, and then used them for seawater concentration process. Both the water uptake and resistance were lower for our ion-track grafted membranes than for the conventional $$gamma$$-ray-grafted membranes. The results would be because local and high-density energy deposition due to the ion beam enabled us to control the membrane structure in a nanometer scale. We demonstrate our membranes are suitable for this application.

Journal Articles

Microfabrication of fluoropolymers using ion beam irradiation

Kitamura, Akane; Kobayashi, Tomohiro*

Hoshasen Kagaku (Internet), (104), p.29 - 34, 2017/10

no abstracts in English

3720 (Records 1-20 displayed on this page)