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Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*
Hamon, 32(4), p.165 - 168, 2022/11
We demonstrated the advantage of spin-contrast-variation neutron reflectometry on the structure analysis of buried interface between resin and porous silica layers. The interface structure was not reproduced by the normal Gaussian model, but by the asymmetric interface model where crosslinked polymer chains neither permeate the pore nor follow the surface roughness of the silica layer.
Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*
Journal of Applied Crystallography, 55(5), p.1147 - 1153, 2022/10
Times Cited Count:2 Percentile:37.43(Chemistry, Multidisciplinary)Spin-contrast-variation neutron reflectivity obtains multiple reflectivity curves from a single sample and a single beam source. We used the strong point of the technique to reveal that, although methylated-perhydropolysilazane-derived silica layer has a higher porosity near the interface with acrylic urethane resin, the resin did not permeate the pore network.
Fujita, Yoshitaka; Niizeki, Tomotake*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; Yamauchi, Yusuke*; Malgras, V.*; Kaneti, Y. V.*; Liu, C.-H.*; Hatano, Kentaro*; Suematsu, Hisayuki*; et al.
Bulletin of the Chemical Society of Japan, 95(1), p.129 - 137, 2022/01
Times Cited Count:9 Percentile:63.53(Chemistry, Multidisciplinary)In this work, the mechanisms responsible for the adsorption of molybdate ions on alumina are investigated using in-depth surface analyses carried out on alumina specimens immersed in solutions containing different molybdate ions at different pH values. The obtained results reveal that when alumina is immersed in an acidic solution containing molybdate ions, the hydroxyl groups present on the surface are removed to generate positively charged sites, and molybdate ions (MoO or AlMoOH) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMoOH, which is more easily desorbed than MoO. Furthermore, the enhancement in the Mo adsorption or desorption property may be achieved by enriching the surface of the alumina adsorbent with many -OH groups and optimizing Mo solution to adsorb molybdate ions on alumina as MoO ions. These findings will assist researchers in engineering more efficient and stable alumina-based adsorbents for molybdenum adsorption used in medical radioisotope (Mo/Tc) generators.
Kimura, Akihiro; Niizeki, Tomotake*; Kakei, Sadanori*; Chakrova, Y.*; Nishikata, Kaori; Hasegawa, Yoshio*; Yoshinaga, Hideo*; Chakrov, P.*; Tsuchiya, Kunihiko
JAEA-Technology 2013-025, 40 Pages, 2013/10
Neutron Irradiation and Testing Reactor Center has developed the production of a medical isotope of Mo, the parent nuclide of Tc by the (n,) method using JMTR. The (n,) method has an advantage of easy manufacturing process and low radioactive wastes generation. However, the low radioactivity concentration of Tc is remaining as an issue. Therefore, PZC and PTC have been developed as adsorbent of molybdenum. Meanwhile, it is necessary to recycle the absorbent and Mo for the reduction of the radioactive waste of used-adsorbent and the effective use of limited resources, respectively. This report summarizes results of the synthesis of Mo adsorbents such as PZC and PTC, and the performance tests.
Kakei, Sadanori*; Kimura, Akihiro; Niizeki, Tomotake*; Ishida, Takuya; Nishikata, Kaori; Kurosawa, Makoto; Yoshinaga, Hideo*; Hasegawa, Yoshio*; Tsuchiya, Kunihiko
Proceedings of 6th International Symposium on Material Testing Reactors (ISMTR-6) (Internet), 7 Pages, 2013/10
The Japan Materials Testing Reactor (JMTR) is expected to contribute to the expansion of industrial utilization, such as the domestic production of Mo for the medical diagnosis medicine Tc. Production by the (n, ) method is proposed as domestic Mo production in JMTR because of the low amount of radioactive wastes and the easy Mo/Tc production process. Molybdenum oxide (MoO) pellets, poly zirconium compounds (PZC) and poly titanium compounds (PTC) are used as the irradiation target and generator for the production of Mo/Tc by the (n, ) method. However, it is necessary to use the enriched MoO, which is very expensive, to increase the specific activity of Mo. Additionally, a large amount of used PZC and PTC is generated after the decay of Mo. Therefore, this recycling technology of used PZC/PTC has been developed to recover molybdenum (Mo) as an effective use of resources and a reduction of radioactive wastes. The total Mo recovery rate of this process was 95.8%. From the results of the hot experiments, we could demonstrate that the recovery of MoO and the recycling of PZC are possible. In the future, the equipment of recovering Mo will be installed in JMTR-Hot Cell, and this recycling process will be able to contribute to the reduction of production costs of Tc and the reduction of radioactive wastes.
Niizeki, Tomotake*; Hishinuma, Yukio*; Suzuki, Masashi*; Hasegawa, Yoshio*; Nishikata, Kaori; Kimura, Akihiro; Ishida, Takuya; Tanimoto, Masataka; Tsuchiya, Kunihiko
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no abstracts in English
Nishikata, Kaori; Kimura, Akihiro; Kato, Yoshiaki; Kurosawa, Makoto; Ishida, Takuya; Tsuchiya, Kunihiko; Kakei, Sadanori*; Yoshinaga, Hideo*; Niizeki, Tomotake*; Hasegawa, Yoshio*
no journal, ,
no abstracts in English
Nishikata, Kaori; Kimura, Akihiro; Kakei, Sadanori*; Niizeki, Tomotake*; Ishida, Takuya; Yoshinaga, Hideo*; Hasegawa, Yoshio*; Tsuchiya, Kunihiko
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Every year in Japan, nuclear medical of about 900,000 cases are carried out using technetiume-99m (Tc). It is ranked as the second in the world. But all of the Tc is imported from the other countries. Therefore, we are developing the (n, ) method for Mo production, as part of "increase of industrial use" in resumed operations after restart of Japan Materials Tasting Reactor (JMTR). In the study to establish the Mo production method through the (n, ) process domestically using the JMTR, three different MoO powders such as fresh, recycled and Mo enriched ones were selected, and characterized as in SEM and sintering. As a result, the high dense MoO pellet manufactured by the fresh powder attained over 90%T. D. at the sintering temperature of 500C. On the other hand, pellets manufactured by the other powders needs sintering temperature above 580C to attain over 90%T.D., resulting in an influence on the particle size and shape dependences for the sintering property.
Tsuchiya, Kunihiko; Kawamata, Kazuo; Takeuchi, Nobuhiro*; Ishizaki, Hiroyuki*; Niizeki, Tomotake*; Kakei, Sadanori*; Fukumitsu, Nobuyoshi*; Araki, Masanori
no journal, ,
no abstracts in English
Suzuki, Yoshitaka; Niizeki, Tomotake*; Kitagawa, Tomoya*; Nishikata, Kaori; Matsukura, Minoru*; Hasegawa, Yoshio*; Tanase, Masakazu*; Fukumitsu, Nobuyoshi*; Yamauchi, Yusuke*; Ariga, Katsuhiko*; et al.
no journal, ,
no abstracts in English
Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Torikai, Naoya*; Niizeki, Tomotake*
no journal, ,
Scattering of neutrons against protons remarkably depends on relative direction of their spins. Spin contrast variation is a technique to determine structure of composite materials using the polarization-dependent neutron scattering against proton. Recently, we have developed the first SCV neutron reflectivity technique for structural analysis of multilayer films. Structure of multilayer films can be determined from the proton-polarization dependent polarized neutron scatterings.
Nishikata, Kaori; Kimura, Akihiro; Kato, Yoshiaki; Kurosawa, Makoto; Ishida, Takuya; Tsuchiya, Kunihiko; Kakei, Sadanori*; Yoshinaga, Hideo*; Niizeki, Tomotake*; Hasegawa, Yoshio*
no journal, ,
no abstracts in English