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Izumida, Wataru*; Okuyama, Rin*; Sato, Kentaro*; Kato, Takeo*; Matsuo, Mamoru
Physical Review Letters, 128(1), p.017701_1 - 017701_6, 2022/01
Times Cited Count：4 Percentile：67.44(Physics, Multidisciplinary)Miyao, Tomoaki*; Miura, Akihiko
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1031 - 1034, 2018/08
no abstracts in English
Miura, Akihiko; Moriya, Katsuhiro; Miyao, Tomoaki*
Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.5022 - 5025, 2018/06
A wire-scanner monitor using metallic wire is reliably employed for the beam-profile measurement in the J-PARC linac. Because the loading of negative hydrogen (H
) ion beam on a wire increases under high-current beam operation, we focus on using a high-durability beam profile monitors by attaching another wire material. Carbon nanotubes (CNT) are made of graphite in a cylindrical shape and have a tensile strength not less than 100 times that of steel. The electric conductivity has higher than that of metals, and hardness is endured thermally around 3000
C in a vacuum circumstance. We applied the wires made from CNT to WSM and measured transverse profiles with a 3-MeV H beam. As a result, we obtained the equivalent signal levels taken by carbon wire made of polyacrylonitrile without any damage. In this paper, the signal response when the CNT is irradiated with an H beam and the result of beam profile measurement. In addition, the surface of CNT after 3-MeV beam operation was observed.
Miyao, Tomoaki*; Miura, Akihiko
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.572 - 576, 2017/12
no abstracts in English
Miura, Akihiko; Miyao, Tomoaki*
no journal, ,
no abstracts in English
Yamada, Masaaki*; Segawa, Tomoomi; Fukasawa, Tomonori*; Ishigami, Toru*; Fukui, Kunihiro*
no journal, ,
The microwave heating method is used in the reprocessing process of spent fuels. It is possible to improve the quality of raw powder by using microwave heating and an external heating source together. However, the use of external heating in a microwave irradiation field causes a problem of deterioration of equipment. Therefore, the hybrid heating using a carbon nanotube (CNT) -containing alumina composite material with a large relative permittivity as an external heating source has been studied. To clarify the effect of the CNT content on the dielectric properties, the microwave heating characteristics were measured and evaluated, and numerical simulation was carried out. From these results, the microwave heating characteristics can be controlled by adjusting the CNT content in the CNT-containing alumina composite material.
Tamaru, Ayaka*; Segawa, Tomoomi; Yamada, Masaaki*; Fukasawa, Tomonori*; Ishigami, Toru*; Fukui, Kunihiro*
no journal, ,
The microwave heating method is used in the reprocessing process of spent fuels. It is possible to improve powder quality by microwave and external heating together. However, the use of external heating in a microwave irradiation field causes a problem of deterioration of equipment. Hybrid heating using CNT-containing alumina with a large relative permittivity as an external heating source has been studied. The characteristics of the hybrid heating in a cavity-type reactor and the relationship between the relative dielectric losses of the materials were evaluated. The relative dielectric losses of the CNT-containing alumina and sample powders were measured by the cavity resonator method and the MW-TG method, respectively. The relative dielectric loss measured by the MW-TG was consistent with the selectivity of heating and was confirmed to be an appropriate index for evaluating the microwave heating characteristics.
Tamaru, Ayaka*; Nagakawa, Genta*; Segawa, Tomoomi; Fukasawa, Tomonori*; Ishigami, Toru*; Fukui, Kunihiro*
no journal, ,
This study aims to investigate the effect of hybrid heating on the denitration reaction of a nickel nitrate aqueous solution to evaluate the feasibility of hybrid heating method with an alumina jacket containing carbon nanotube (CNT) as a microwave heating medium. When an alumina jacket without CNT was used, the temperature decreased and the denitration reaction stopped due to the formation of an intermediate product Ni
(NO
)
(OH)
with low dielectric loss. Whereas, when an alumina jacket containing 0.2 mass% CNT was used, the denitration reaction was completed and nickel oxide particles were obtained. It is presumed that the denitration reaction proceeds by heat conduction from the CNT-containing alumina jacket because the jacket is selectively heated by microwaves more than the Ni(NO)(OH). It is clarified that hybrid heating can be realized by a CNT-containing alumina jacket.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Yamada, Masaaki*; Tamaru, Ayaka*; Nagakawa, Genta*; Fukasawa, Tomonori*; Ishigami, Toru*; Fukui, Kunihiro*; Murakami, Hiroyuki*
no journal, ,
To compensate for heat dissipation through the vessel and reduced microwave absorption due to intermediate in the fabrication process of the metallic oxide powder by the microwave heating denitration method, alumina composite ceramic material containing CNT which has a high relative dielectric loss as the external heating source with self-heating by microwave heating. The CNT was observed by SEM of the CNT-containing alumina composite ceramic material to observe the CNT presence in the base material of alumina. The surface resistivities decreased significantly when the CNT content increased from 0.2 to 0.5 mass%, and there was not much of a significant difference when the CNT content increased from 0.5 to 1.0 mass%. These results are consistent with the results of the previous studies of the apparent dielectric loss that showed a trend toward an increase in the apparent dielectric loss as the CNT content increased from 0.2 to 0.5 mass% in the CNT-containing alumina composites.
