Synergistic effect of aluminum lactate and sodium molybdate on freshwater corrosion of carbon steel under irradiation

Otani, Kyohei; Kato, Chiaki; Igarashi, Takahiro

Corrosion, 79(11), p.1277 - 1286, 2023/11

https://doi.org/10.5006/4386

Structural characterization by X-ray analytical techniques of calcium aluminate cement modified with sodium polyphosphate containing cesium chloride

Takahatake, Yoko; Watanabe, So; Irisawa, Keita; Shiwaku, Hideaki; Watanabe, Masayuki

Journal of Nuclear Materials, 556, p.153170_1 - 153170_7, 2021/12

https://doi.org/10.1016/j.jnucmat.2021.153170

Desorption behavior of Cs from clay minerals by thermal heating in a vacuum; Analyses by thermal desorption spectroscopy and synchrotron radiation X-ray photoelectron spectroscopy

Hirao, Norie; Shimoyama, Iwao; Baba, Yuji; Izumi, Toshinori; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi

Bunseki Kagaku, 65(5), p.259 - 266, 2016/05

https://doi.org/10.2116/bunsekikagaku.65.259

After the Fukushima nuclear plant accident, radiocesium was strongly fixed to clay minerals in the soil. Some dry methods with heating are being developed to remove radiocesium from the soil. In this work, we propose a new dry method that combines heat treatment in vacuum and molten salts to reduce the processing temperature in dry methods. Vermiculite saturated with non-radioactive Cs was heated in vacuum, and Cs contents in the vermiculite were compared before and after heating using X-ray photoelectron spectroscopy. Approximately 40% of cesium were removed by heating at 800C for three minutes when only vermiculite was heated. Approximately 70% of cesium were removed by heating at 450C for three minutes when vermiculite was heated with NaCl/CaCl mixed salts. Based on these results, this method is expected to reduce temperature and increase efficiency on dry methods for cesium removal from clay minerals.

Characterization of interface defects related to negative-bias temperature instability in ultrathin plasma-nitrided SiON/Si100 systems

Fujieda, Shinji*; Miura, Yoshinao*; Saito, Motofumi*; Teraoka, Yuden; Yoshigoe, Akitaka

Microelectronics Reliability, 45(1), p.57 - 64, 2005/01

https://doi.org/10.1016/j.microrel.2004.02.017

To characterize the interface defects that are responsible for the negative-bias temperature instability (NBTI) of a thin plasma-nitrided SiON/Si system, we carried out inerface trap density measurements, electron-spin resonance spectroscopy and synchrotron radiation XPS. The NBTI was shown to occur mainly through the dehydrogenation of the interfacial Si dangling bonds (P defects). Although we suggest that non- P defects are also generated by the negative-bias temperature stress, nitrogen dangling bonds do not seem to be included. The plasma-nitridation process was confirmed to generate sub-oxides at the interface and thus increase the interface trap density. Furthermore, it was found that the nitridation induces another type of P defect than that at pure-SiO/Si interfacec. Such an increase and structural change of the interfacial defects are likely the causes of the nitridation-enhanced NBTI.

Energetic deuterium and helium irradiation effects on chemical structure of CVD diamond

Sasaki, Masayoshi*; Morimoto, Yasutomi*; Kimura, Hiromi*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi; Okuno, Kenji*

Journal of Nuclear Materials, 329-333(Part1), p.899 - 903, 2004/08

https://doi.org/10.1016/j.jnucmat.2004.04.275

A CVD diamond has been the reference material of a torus widow for a rf heating system in a fusion reactor. Since the window is in the circumstance of tritium, helium and radio activated dust, it is important to elucidate the effect of ions on chemical structure of the diamond, existing states of tritium and tritium inventory. Polycrystalline CVD diamond disks(=10.0mm, t=0.21mm) used in this study are the same grade as rf windows. After sputtering the surface with 1.0 keV Ar to remove oxygen impurity, the sample was irradiated with deuterium (D) or helium ions (He) at an angle of 0 degrees to the surface normal. The irradiation energies of deuterium and helium are 0.25 keV D and 0.45 keV He, respectively. The structural change of the irradiated sample was measured by X-ray Photoelectron Spectroscopy (XPS) technique. The C1s peak shift toward lower binding energy side was observed when deuterium ions irradiated. This result indicates that the diamond changes to amorphous carbon due to formation of C-D bond.

Electronic structures of ultra-thin silicon carbides deposited on graphite

Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Nath, K. G.

Applied Surface Science, 234(1-4), p.246 - 250, 2004/07

https://doi.org/10.1016/j.apsusc.2004.05.045

no abstracts in English

Analyses of hydrogen isotope distributions in the outer target tile used in the W-shaped divertor of JT-60U

Oya, Yasuhisa*; Morimoto, Yasutomi*; Oyaizu, Makoto*; Hirohata, Yuko*; Yagyu, Junichi; Miyo, Yasuhiko; Goto, Yoshitaka*; Sugiyama, Kazuyoshi*; Okuno, Kenji*; Miya, Naoyuki; et al.

Physica Scripta, T108, p.57 - 62, 2004/00

no abstracts in English

Chemical-state analysis for low-dimensional Si and Ge films on graphite

Nath, K. G.; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Baba, Yuji

Journal of Applied Physics, 94(7), p.4583 - 4588, 2003/10

https://doi.org/10.1063/1.1605253

no abstracts in English

XPS study of Pb(II) adsorption on -AlO surface at high pH conditions

Yoshida, Takahiro; Yamaguchi, Tetsuji; Iida, Yoshihisa; Nakayama, Shinichi

Journal of Nuclear Science and Technology, 40(9), p.672 - 678, 2003/09

https://doi.org/10.3327/jnst.40.672

Pb(II) adsorption on -AlO at high pH condition (11 pH 13) was studied in NaNO solutions. With increasing pH from 11, Pb(II) uptake by -AlO was decreased regardless to sodium concentration (0.1 and 1.0 M). XPS spectra showed binding energy of adsorbed Pb (4f) had no dependence on pH and adsorption density and was higher than that of orthorhombic yellow PbO and Pb(NO). Molecular orbital (MO) calculation revealed lowest unoccupied molecular orbital (LUMO) energy of Pb(OH) was about 6 eV higher than that of Pb(OH), and suggested chemical reactivity of Pb(OH) with deprotonated surface hydroxyl ligand [AlO] was expected to be less than that of Pb(OH). Although Pb(II) is adsorbed on -AlO as inner-sphere surface complex, bonding between Pb(II) and -AlO shows less covalent nature.

Analyses of erosion and re-deposition layers on graphite tiles used in the W-shaped divertor region of JT-60U

Goto, Yoshitaka*; Yagyu, Junichi; Masaki, Kei; Kizu, Kaname; Kaminaga, Atsushi; Kodama, Kozo; Arai, Takashi; Tanabe, Tetsuo*; Miya, Naoyuki

Journal of Nuclear Materials, 313-316, p.370 - 376, 2003/03

https://doi.org/10.1016/S0022-3115(02)01354-5

Erosion and re-deposition were studied for graphite tiles from W-shaped divertor region of JT-60U in Jun. 1997 - Oct. 1998 periods in which more than 3000 D-D discharges were made with all-carbon wall with boronizations and inner-private flux pumping. On the outer divertor targets, erosion was dominant: maximum erosion depth of around 20 micrometers was measured, while on the inner targets, re-deposition was dominant: columnar structure layers and laminar/columnar-layered structures of maximum thickness around 60 micrometers were found. Through XPS analysis, compositions of the re-deposition layers at a around mid point on the inner target were 94 - 95 at% C, 3 - 4 at% B, and less than 0.6 at% O, Fe, Cr, and Ni. Boron is mainly bound to Carbon. No continuous deposition layers on the dome top/outer wing, while deposition layers were found on the inner wing. Observed in/out asymmetry is attributable to in/out asymmetry of plasma particle conditions in the divertor region.