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Journal Articles

Study on decontamination of steel surface contaminated with uranium hexafluoride by acidic electrolytic water

Nakayama, Takuya; Nomura, Mitsuo; Mita, Yutaka; Yonekawa, Hitoshi*; Bunbai, Misako*; Yaita, Yumi*; Murata, Eiichi*; Hosaka, Katsumi*; Sugitsue, Noritake

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 8 Pages, 2019/05

Clearance of contaminated metal is important for recycling and volume reduction of radioactive waste. Among applicable decontamination technologies, immersion method with ultrasonic cleaning is considered to be effective for metal materials having various shapes. in this study is to demonstrate decontamination of carbon steel contaminated by uranium hexafluoride to the target level for clearance (less than 0.04 Bq/cm$$^{2}$$), and minimize secondary waste. In this test, acidic electrolytic water, dilute hydrochloric acid, dilute sulfuric acid and ozone water with various pH and redox potential were used as decontamination solutions to be tested. We found that acidic electrolytic water is effective solution for decontamination of carbon steel contaminated by uranium hexafluoride. It could be decontaminate less than target level for clearance, and reduced secondary waste relatively.

Journal Articles

Immobilization of alkyl chain molecules on oxide surface using phosphonic acid as an anchor

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Yaita, Tsuyoshi

e-Journal of Surface Science and Nanotechnology (Internet), 10, p.367 - 373, 2012/07

To apply organic thin films as new devices, it is important to immobilize organic molecules on oxide surfaces. In this study, we investigated the formation of organic self-assembled monolayer on the oxide surface. Decyl phosphonic acid (DPA) molecules were used as the adsorbed molecule on the surface. The DPA film was prepared by immersing the sapphire substrate in DPA ethanol solution. The sample was measured by XPS using synchrotron soft X-ray. For the P 1s XPS spectra of the DPA powder and the DPA film on the sapphire surface, a single peak was observed and the binding energies of the two samples were almost the same. And we measured the sample by the total reflection (TR) XPS, which is highly surface sensitive method. Compared with the normal XPS, the intensity of the C 1s peak in TR-XPS was enhanced. As a result, it was elucidated that the phosphonic acid of the DPA molecule was located at the lower side, while the alkyl chain was located at the upper side on the surface.

Journal Articles

Anchoring of alkyl chain molecules on oxide surface using silicon alkoxide

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Yaita, Tsuyoshi

Applied Surface Science, 258(6), p.2034 - 2037, 2012/01

 Times Cited Count:4 Percentile:21.91(Chemistry, Physical)

In order to apply the organic thin films to electric and optical devices, the immobilization of organic molecules on inorganic substrate is essential. Considering optical devices, it is important to immobilize organic molecules on oxide surfaces, because many of oxides have insulating and transparent properties. In this study, we have investigated the chemical states of the interface between organic molecules with silicon alkoxide and sapphire surfaces by X-ray photoelectron spectroscopy and near edge absorption fine structure (NEXAFS). Octadecyl-triethoxy-silane (ODTS) molecules which are terminated by silicon alkoxide were adsorbed on sapphire surfaces. On the basis of the Si 1s XPS spectra for monolayer, it is supposed that the chemical bond between silicon alkoxide and the surface is formed. For Si K-edge NEXAFS spectra, the polarization dependence was observed, which suggests that the Si-O bond in ODTS was located perpendicular to the surface.

Journal Articles

Immobilization of alkyl chain molecules with phosphonic acid on oxide surface

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Yaita, Tsuyoshi

Photon Factory Activity Report 2011, Part B, P. 94, 2012/00

Immobilization of organic molecules on oxide surface has been investigated using phosphonic acid as an anchor. The molecule investigated was decyl-phosphonic acid (DPA). The DPA film was formed by immersing the sapphire substrate in DPA ethanol solution. The results for X-ray photoelectron spectra (XPS) showed that the alkyl chain of the DPA molecules is located at the upper side, while the phosphonic acid is the lower side on the surface. The XPS and near-edge X-ray absorption fine structure (NEXAFS) results indicated that the DPA film became homogeneous monolayer by heating at 250$$^{circ}$$C. It is concluded that the phosphonic acid is an excellent anchor that immobilizes the organic molecules on an oxide surface.

Journal Articles

Formation of C$$_{rm n}$$H$$_{rm x}$$ (n$$geq$$2) molecules from adsorbed methane by low-energy ion irradiation

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori; Hirao, Norie; Yaita, Tsuyoshi

Hyomen Kagaku, 29(8), p.489 - 494, 2008/08

The formation of molecular ions and neutral molecules from adsorbed CH$$_{4}$$, CD$$_{4}$$ and N$$_{2}$$ following 1 keV He$$^{+}$$ ion irradiation has been investigated. The thickness of the adsorbed layer was precisely controlled. For mono-layered methane, only monomer ions (CH$$_{rm x}$$$$^{+}$$) were desorbed, while a large number of heavy ions (C$$_{rm n}$$H$$_{rm x}$$$$^{+}$$) up to n = 20 as well as heavy neutral molecules (C$$_{rm n}$$H$$_{rm x}$$) were desorbed from multi-layered film. Among the desorbed ions and neutral molecules, molecules with C-C covalent bonds such as acetylene and ethylene were found. The results indicate that chemical bonds are newly formed by ion irradiation. Based on the results for thickness dependences of the mass spectra and calculation of He$$^{+}$$ energy loss process from TRIM-Code, it was elucidated that the monomer ions are desorbed from the top surface layer through single electron excitation. On the other hand, the cluster ions are formed mainly in the inside of the layers along the nuclear track due to phonon excitation, which is produced by nuclear collision between incident He$$^{+}$$ ions and adsorbed molecules.

Journal Articles

Study on selective separation of uranium(VI) by new $$N$$,$$N$$-dialkyl carboxyamides

Suzuki, Shinichi; Yaita, Tsuyoshi; Sugo, Yumi; Kimura, Takaumi

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1137 - 1141, 2007/09

no abstracts in English

Journal Articles

Facile preparation and the crystal structure of ${it N,N'}$-dialkyl-2,6-pyridinedimethanaminium halide

Kobayashi, Toru; Yaita, Tsuyoshi; Sugo, Yumi; Suda, Hiroki*; Suzuki, Shinji*; Fujii, Yuki*; Nakano, Yoshiharu*

Journal of Heterocyclic Chemistry, 43(3), p.549 - 557, 2006/05

 Times Cited Count:4 Percentile:11.53(Chemistry, Organic)

Journal Articles

Novel separation system of trivalent actinides-combined effects of substituted tris(2-pyridylmethyl)amine ligand and hydrophobic counter-anion

Ishimori, Kenichiro*; Watanabe, Masayuki; Kimura, Takaumi; Yaita, Tsuyoshi; Yamada, Takashi*; Kataoka, Yumiko*; Shinoda, Satoshi*; Tsukube, Hiroshi*

Chemistry Letters, 34(8), p.1112 - 1113, 2005/08

 Times Cited Count:12 Percentile:44.35(Chemistry, Multidisciplinary)

Stereochemical substitution on tripod ligand significantly offered efficient separation of trivalent actinides from trivalent lanthanides. Liquid-liquid extraction using chiral tris(2-pyridylmethyl)amine ligands as an extractant exhibited high efficiency and selectivity for trivalent actinides. A combination of chiral ligand and 2-bromodecanoic acid further enhanced extraction performance for trivalent actinides.

Journal Articles

Study of tritium retention in graphite by simulating first wall circumstances

Yaita, Yumi*; Ohira, Shigeru; Okuno, Kenji

Fusion Technology, 28(3), p.1294 - 1298, 1995/10

no abstracts in English

Oral presentation

Formation of cluster ions from adsorbed molecules at extremely low temperature by ion irradiation

Narita, Ayumi*; Baba, Yuji; Honda, Mitsunori; Hirao, Norie*; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Desorption of cluster ions from adsorbed molecules under cryojenic condition by ion irradiation

Narita, Ayumi*; Honda, Mitsunori; Hirao, Norie*; Baba, Yuji; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Development of N,N-dialkylamide for U(VI) selective separation with high decontamination factor

Suzuki, Shinichi; Yaita, Tsuyoshi; Sugo, Yumi; Kimura, Takaumi

no journal, , 

no abstracts in English

Oral presentation

Desorption of cluster ions from adsorbed molecules under cryogenic condition by low-energy ion irradiation

Narita, Ayumi; Honda, Mitsunori; Hirao, Norie*; Baba, Yuji; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Study on selective separation of U(VI) by N,N-dialkylamides

Suzuki, Shinichi; Yaita, Tsuyoshi; Sugo, Yumi; Kimura, Takaumi

no journal, , 

no abstracts in English

Oral presentation

Formation of CnHx molecules from adsorbed methane under cryogenic condition by ion beam irradiation

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori; Hirao, Norie*; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Formation of molecules from adsorbed methane under cryogenic condition by low-energy ion irradiation

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori; Hirao, Norie*; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Development of new N,N-dialkylamides for U(VI) selective separation with high DF

Suzuki, Shinichi; Yaita, Tsuyoshi; Sugo, Yumi; Kimura, Takaumi

no journal, , 

no abstracts in English

Oral presentation

Chemical bond formation in adsorbed and condensed methane by He+ ion irradiation

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori; Hirao, Norie; Yaita, Tsuyoshi

no journal, , 

Photon or electron irradiation breaks chemical bond and induces desorption of fragment. However, formation of chemical bond from adsorbed light molecules, such as methane, by high energy radiation has scarcely been reported. This process is important in space, because organic molecules can be formed through these reactions. In this report, we have investigated formation of molecular ions and neutral molecules with covalent bond from frozen methane by He+ ion irradiation. It was found that acetylene ion(C2H2+), and ethylene ion(C2H4+) with covalent bond were formed by He+ ion irradiation. These results were compared with Monte-Carlo simulation for energy-loss processes of He+ ions in solid methane. As a result, it was elucidated that molecular ions are formed inside of frozen methane by high-density excitation due to nuclear collision. On the other hand, neutral molecules are formed by rapid evaporation due to temperature increase along the nuclear track.

Oral presentation

Desorption of alkene and alkyne compound from adsorbed methane by ion irradiation

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori; Hirao, Norie; Yaita, Tsuyoshi

no journal, , 

no abstracts in English

Oral presentation

Immobilization of alkane molecules on oxide surface with silicone alkoxide

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Yaita, Tsuyoshi

no journal, , 

Organic thin films have advantages over currently used Si-devises, and they can have new functions that Si-devices don't have. However, there are several problems to be solved such as chemical states of organic-inorganic interfaces and molecular orientations. In this study, we investigated chemical states of the interface between mercapto-propyl-trimetoxy-silane (MPTS) and aluminum oxide using X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS). For the XP spectra, it was elucidated that MPTS molecules and aluminum oxide surface made the chemical bond through silicon alkoxide. Moreover, the NEXAFS spectra at the silicon K-edge show a polarization dependence. From these results, we concluded that MPTS molecules locate perpendicular direction to the aluminum oxide surface.

39 (Records 1-20 displayed on this page)