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Nagasawa, Makoto*; Shimizu, Yusuke*; Yamaguchi, Akiko; Tokunaga, Kohei; Mukai, Hiroki*; Aoyagi, Noboru; Mei, H.; Takahashi, Yoshio*
Chemical Geology, 670, p.122431_1 - 122431_25, 2024/12
Times Cited Count:0 Percentile:0.00(Geochemistry & Geophysics)Hou, L.*; Toda, Kanako*; Mei, H.; Aoyagi, Noboru; Saito, Takumi*
Journal of Nuclear Science and Technology, 61(11), p.1488 - 1498, 2024/11
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Sugiura, Yuki; Ishidera, Takamitsu; Aoyagi, Noboru; Mei, H.; Saito, Takumi*; Tachi, Yukio
Applied Clay Science, 258, p.107476_1 - 107476_10, 2024/09
Times Cited Count:1 Percentile:0.00(Chemistry, Physical)Aoyagi, Noboru; Motokawa, Ryuhei; Okumura, Masahiko; Ueda, Yuki; Saito, Takumi*; Nishitsuji, Shotaro*; Taguchi, Tomitsugu*; Yomogida, Takumi; Sazaki, Gen*; Ikeda, Atsushi
Communications Chemistry (Internet), 7, p.128_1 - 128_13, 2024/06
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Guerinoni, E.*; Giusti, F.*; Dourdain, S.*; Dufrche, J.-F.*; Motokawa, Ryuhei; Ueda, Yuki; Aoyagi, Noboru; Zemb, T.*; Pellet-Rostaing, S.*
Journal of Molecular Liquids, 403, p.124820_1 - 124820_11, 2024/06
Times Cited Count:0 Percentile:0.00(Chemistry, Physical)Mei, H.; Aoyagi, Noboru; Saito, Takumi*; Tanaka, Kazuya; Sugiura, Yuki; Tachi, Yukio
Applied Geochemistry, 162, p.105926_1 - 105926_8, 2024/02
Times Cited Count:2 Percentile:84.49(Geochemistry & Geophysics)Liu, J.; Dotsuta, Yuma; Kitagaki, Toru; Aoyagi, Noboru; Mei, H.; Takano, Masahide; Kozai, Naofumi
Journal of Nuclear Science and Technology, 60(8), p.1002 - 1012, 2023/08
Times Cited Count:1 Percentile:34.39(Nuclear Science & Technology)Murota, Kento*; Aoyagi, Noboru; Mei, H.; Saito, Takumi*
Applied Geochemistry, 152, p.105620_1 - 105620_11, 2023/05
Times Cited Count:4 Percentile:68.69(Geochemistry & Geophysics)Massey, D.*; Williams, C. D.*; Mu, J.*; Masters, A. J.*; Motokawa, Ryuhei; Aoyagi, Noboru; Ueda, Yuki; Antonio, M. R.*
Journal of Physical Chemistry B, 127(9), p.2052 - 2065, 2023/03
Times Cited Count:2 Percentile:22.86(Chemistry, Physical)Falyouna, O.*; Bensaida, K.*; Maamoun, I.; Ashik, U. P. M.*; Tahara, Atsushi*; Tanaka, Kazuya; Aoyagi, Noboru; Sugihara, Yuji*; Eljamal, O.*
Journal of Cleaner Production, 342, p.130949_1 - 130949_15, 2022/03
Times Cited Count:58 Percentile:98.42(Green & Sustainable Science & Technology)Mei, H.; Aoyagi, Noboru; Saito, Takumi*; Kozai, Naofumi; Sugiura, Yuki; Tachi, Yukio
Applied Geochemistry, 136, p.105178_1 - 105178_8, 2022/01
Times Cited Count:18 Percentile:89.94(Geochemistry & Geophysics)Ueda, Yuki; Kikuchi, Kei*; Tokunaga, Kohei; Sugita, Tsuyoshi; Aoyagi, Noboru; Tanaka, Kazuya; Okamura, Hiroyuki
Solvent Extraction and Ion Exchange, 39(5-6), p.491 - 511, 2021/00
Times Cited Count:4 Percentile:22.30(Chemistry, Multidisciplinary)no abstracts in English
Aoyagi, Noboru; Nguyen, T. T.*; Kumagai, Yuta; Nguyen, T. V.*; Nakada, Masami; Segawa, Yukari; Nguyen, H. T.*; Le, B. T.*
ACS Omega (Internet), 5(13), p.7096 - 7105, 2020/04
Times Cited Count:4 Percentile:17.04(Chemistry, Multidisciplinary)Oishi, Tomoji*; Kimura, Yu*; Nakajima, Kiyohiko*; Watanabe, Masayuki; Aoyagi, Noboru
Materials Sciences and Applications, 11(3), p.195 - 203, 2020/03
A high-efficiency synthesis method for a latent pigment of red pigment diketo-pyrrolo-pyrrole (Pig. Red 272:272DPP), which is important as a functional organic pigment, was investigated, and the investigation results revealed that irradiation of microwaves (MWs) for several seconds to 272 DPP in NMP (N-methyl-2-pyrrolidone) solvent yielded DPP latent pigment (272DPP-BOC) at a high yield of 86.2%. Two kinds of latent-pigment crystals, namely, red and yellow, were obtained by recrystallization, and it was found that the fluorescence-emission properties of the two kinds differ significantly. Single-crystal X-ray structural analysis showed that the difference in the fluorescence-emission properties of the two types is derived from the difference in their crystal structures.
Ma, J.*; Zhang, Y.*; Collins, R. N.*; Tsarev, S.*; Aoyagi, Noboru; Kinsela, A. S.*; Jones, A. M.*; Waite, T. D.*
Environmental Science & Technology, 53(5), p.2739 - 2747, 2019/03
Times Cited Count:58 Percentile:89.08(Engineering, Environmental)Aoyagi, Noboru; Palladino, G.*; Nagasaki, Shinya*; Kimura, Takaumi
Bulletin of the Chemical Society of Japan, 91(6), p.882 - 890, 2018/06
Times Cited Count:3 Percentile:11.01(Chemistry, Multidisciplinary)The speciation and coordination geometries of M(III)-citrate complexes in aqueous solutions, where M denotes Eu, Tb, Lu, or Cm, are studied using potentiometric titration, nuclear magnetic resonance spectroscopies. Their photophysical properties are also characterized by time-resolved fluorescence spectra. The formation constants of mononuclear, dinuclear, and trinuclear Lu-citrate species were determined by potentiometric titration in 3.00 M NaClO aqueous media. Terminal carboxylic conformation in trinuclear complexes comprised both the five- and six-membered rings at different exchanging rates. Hydration states evaluated for Eu
ions are the chemical formula of [Eu(Cit)
(H
O)
]
and [Eu
(OH)
(Cit)
(H
O)
]
. These complexes in aqueous solution have geometrical similarity to the crystal structures in the literature. Furthermore, the entity of the hetero-trinuclear complex induces the intramolecular energy transfer from Tb
to Eu
. The incorporation of Cm
into these homo/hetero-trinuclear citrate complexes proved to be a successful trial to probe the formation of actinide polymer at a trace level.
Saito, Takumi*; Aoyagi, Noboru; Terashima, Motoki
Journal of Nuclear Science and Technology, 54(4), p.444 - 451, 2017/04
Times Cited Count:7 Percentile:53.23(Nuclear Science & Technology)Humic substances (HSs) are ubiquitous in various environments including deep underground and play an important role in the speciation and mobility of radionuclides. The binding of Eu, a chemical homologue of trivalent actinide ions, to HSs isolated from sedimentary groundwater at -250 m below the surface was studied by time-resolved laser fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) as a function of pH and salt concentration. PARAFAC modeling reveals the presence of multiple factors that corresponds to different Eu
species. These factors resemble those observed for Eu
binding to HSs from surface environments; however, detailed comparison shows that there are some particularities in Eu
binding to the deep groundwater HSs. The distribution coefficients (
) of Eu
binding to the HSs calculated from the PARAFAC modeling exhibits a rather strong salt effect. At 0.01 M NaClO
the
values are relatively large and comparable to those to the surface HSs; they are decreaed at 0.1 M NaClO
by more than an order of the magnitude. The
values are larger for humic acid fraction of the deep underground HSs than fulvic acid over the entire range of pH and salt concentration investigated in this study.
Segawa, Yukari; Horita, Takuma; Kitatsuji, Yoshihiro; Kumagai, Yuta; Aoyagi, Noboru; Nakada, Masami; Otobe, Haruyoshi; Tamura, Yukito*; Okamoto, Hisato; Otomo, Takashi; et al.
JAEA-Technology 2016-039, 64 Pages, 2017/03
The laboratory building No.1 for the plutonium research program (Bldg. Pu1) was chosen as one of the facilities to decommission by Japan Atomic Energy Agency Reform in September, 2013. The research groups, users of Bldg. Pu1, were driven by necessity to remove used equipment and transport nuclear fuel to other facilities from Bldg. Pu1. Research Group for Radiochemistry proactively established the Used Equipment Removal Team for the smooth operation of the removal in April, 2015. The team classified six types of work into the nature of the operation, removal of used equipment, disposal of chemicals, stabilization of mercury, stabilization of nuclear fuel, transportation of nuclear fuel and radioisotope, and survey of contamination status inside the glove boxes. These works were completed in December, 2015. This report circumstantially shows six works process, with the exception of the approval of the changes on the usage of nuclear fuel in Bldg. Pu1 to help prospective decommission.
Okamura, Hiroyuki; Aoyagi, Noboru; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
RSC Advances (Internet), 7(13), p.7610 - 7618, 2017/01
Times Cited Count:20 Percentile:53.88(Chemistry, Multidisciplinary)The role of bis(trifluoromethanesulfonyl)imide (TfN
) anions in the ionic liquid-water distribution systems of the Eu(III) chelates with 2-thenoyltrifluoroacetone (Htta) was investigated by the liquid-liquid distribution and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The effect of the ionic liquids on the distribution constant of Eu(tta)
was evaluated by the regular solution theory. The distribution constant of Eu(tta)
in 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C
mim][Tf
N]) was increased dramatically by the solvation effects of Eu(tta)
in [C
mim][Tf
N]. TRLFS for [Eu(tta)
(H
O)
] synthesized revealed that the Eu(tta)
chelate was almost completely dehydrated in a series of [C
mim][Tf
N]. The Eu(tta)
chelate exists as di- or tri-hydrates in 1-ethyl-3-methylimidazolium perchlorate ([C
mim][ClO
]) containing 20 M water, whereas mono-hydrated chelate was formed in [C
mim][Tf
N, ClO
] in the presence of 0.50 M Tf
N
and 20 M water. These results show that the coordinated water molecules of [Eu(tta)
(H
O)
] were replaced by the Tf
N
anions. In fact, an anionic adduct, [Eu(tta)
(Tf
N)]
, was observed by electrospray ionization mass spectrometry in the presence of [C
mim][Tf
N].
Sasaki, Takayuki*; Ueda, Kenyo*; Saito, Takumi; Aoyagi, Noboru; Kobayashi, Taishi*; Takagi, Ikuji*; Kimura, Takaumi; Tachi, Yukio
Journal of Nuclear Science and Technology, 53(4), p.592 - 601, 2016/04
Times Cited Count:14 Percentile:76.34(Nuclear Science & Technology)The influences of pH and the concentrations of Eu and NaNO
on the sorption of Eu
to Na-montmorillonite were investigated through batch sorption measurements and time-resolved laser fluorescence spectroscopy (TRLFS). The pH had a little effect on the distribution coefficients (Kd) in 0.01 M NaNO
, whereas the Kd strongly depended on pH at 1 M NaNO
. A cation exchange model combined with a one-site non-electrostatic surface complexation model was successfully applied to the measured Kd. The TRLFS spectra of Eu
sorbed were processed by parallel factor analysis (PARAFAC), which corresponded to one outer-sphere (factor A) and two inner-sphere (factor B and C) complexes. It turned out that factors A and B correspond to Eu
sorbed by ion exchange sites and inner-sphere complexation with hydroxyl groups of the edge faces, respectively. Factor C became dominant at relatively high pH and ionic strength and likely correspond to the precipitation of Eu(OH)
on the surface.