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Tanji, Tamao*; Kusunoki, Yuto*; Nakagawa, Taichi; Takase, Tsugiko*; Ueda, Yuki; Motokawa, Ryuhei; Hinze, W. L.*; Takagai, Yoshitaka*
Langmuir, 41(21), p.13184 - 13191, 2025/06
Times Cited Count:0Ueda, Yuki; Micheau, C.; Akutsu, Kazuhiro*; Tokunaga, Kohei; Yamada, Masako*; Yamada, Norifumi*; Bourgeois, D.*; Motokawa, Ryuhei
Langmuir, 40(46), p.24257 - 24271, 2024/11
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency, selectivity, and phase separation of the organic phase. In this study, we correlated the macroscopic behavior of the extraction of Zr(IV) ions from nitric acid solutions with microscopic structural information in order to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system comprising fluorous phosphate (TFP) in perfluorohexane as compared to the analogous organic extraction system comprising organic phosphate (THP) in n-hexane. Extended X-ray absorption fine structure, neutron reflectometry, and small-angle neutron scattering revealed the local coordination structure around the Zr(IV) ion, the accumulation of extractant molecules at the interface, and the structuration of extractant molecules in the bulk extraction phase, respectively. In the fluorous extraction system, extractant aggregates with were formed after contact with nitric acid. In contrast, in the organic extraction system, only extractant dimers were formed. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.
Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Shibata, Motoki*; Nakanishi, Yohei*; Arakawa, Masato*; Takenaka, Mikihito*; Kida, Takumitsu*; Tokumitsu, Katsuhisa*; Tanaka, Ryo*; et al.
Langmuir, 40(30), p.15758 - 15766, 2024/07
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Nankawa, Takuya; Sekine, Yurina; Matsumura, Daiju; Hiroi, Kosuke; Takata, Shinichi; Kamiya, Yoshimi*; Honda, Takayuki*
Langmuir, 40(11), p.5725 - 5730, 2024/03
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)The chemical reaction between Fe and lacquer has been used to create the black color lacquer since ancient times. Here, the chemical state of Fe ions in black lacquer was investigated by using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and Fourier transform-infrared (FT-IR) spectroscopy. Fe(II) or Fe(III) was added to the lacquer paste to prepare black lacquer films by air drying, heating, or UV irradiation. The XANES spectral features of all the film samples were similar, meaning that the Fe ions in the samples existed in the trivalent state regardless of the oxidation state of the initially added Fe. The corresponding Fourier transforms of the EXAFS spectra around the Fe K-edge were used to investigate Fe sites in the lacquer films. The spectra of all the film samples were similar shapes, but the peak intensities decreased in the order air dried heated
UV irradiated films. This result indicates that heating and UV irradiation made the coordination structure of Fe in the lacquer non-uniform, and that heating caused the greatest non-uniformity. The complementary use of XANES, XAFS, and FT-IR spectroscopy is highly effective for non-destructive analysis of black lacquer in precious cultural artifacts.
Goto, Aki*; Michishio, Koji*; Oka, Toshitaka; Tagawa, Masahito*; Yamashita, Shinichi*
Langmuir, 39(34), p.11954 - 11963, 2023/08
Times Cited Count:1 Percentile:11.04(Chemistry, Multidisciplinary)Atomic oxygen (AO) is one of the dominant components of the residual atmosphere in low Earth orbit. AO collides with spacecraft with translational energy of 5 eV, forming nanoscale protrusions on polymeric materials. This study investigated the size of free-volume holes and the layer thickness that interacted with AO for polyethylene (PE), polypropylene (PP), and polystyrene (PS) by positron annihilation lifetime spectroscopy. By the AO irradiation, oxidized layer formed in the surface, and the maximum depth of the oxidized layer for PE and PP were deeper than for PS. The different sizes of free-volume holes would affect the injection depths of AO, resulting in the oxidized layers' thicknesses and surface morphologies.
Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Bauduin, P.*; Girard, L.*; Diat, O.*
Langmuir, 39(31), p.10965 - 10977, 2023/07
Times Cited Count:11 Percentile:71.78(Chemistry, Multidisciplinary)Liu, Y.*; Miyata, Noboru*; Miyazaki, Tsukasa*; Shundo, Atsuomi*; Kawaguchi, Daisuke*; Tanaka, Keiji*; Aoki, Hiroyuki
Langmuir, 39(29), p.10154 - 10162, 2023/06
Times Cited Count:11 Percentile:74.82(Chemistry, Multidisciplinary)Kobayashi, Taishi*; Fushimi, Tomokazu*; Mizukoshi, Hirofumi*; Motokawa, Ryuhei; Sasaki, Takayuki*
Langmuir, 38(48), p.14656 - 14665, 2022/12
Times Cited Count:3 Percentile:21.39(Chemistry, Multidisciplinary)Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Arima-Osonoi, Hiroshi*; Nakanishi, Yohei*; Takenaka, Mikihito*; Shibata, Motoki*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki; et al.
Langmuir, 38(41), p.12457 - 12465, 2022/10
Times Cited Count:2 Percentile:13.50(Chemistry, Multidisciplinary)Kakiuchi, Takuhiro*; Matoba, Tomoki*; Koyama, Daisuke*; Yamamoto, Yuki*; Yoshigoe, Akitaka
Langmuir, 38(8), p.2642 - 2650, 2022/03
Times Cited Count:2 Percentile:13.50(Chemistry, Multidisciplinary)0xidation processes at the interface and the surface of Si(111) substrate with thin Hf films were studied using photoelectron spectroscopy in conjunction with supersonic oxygen molecular beams (SOMB). The oxidation starts at the outermost Hf layers and produces stoichiometric HfO. Hf silicates (Hf-O-Si configuration) were generated in the vicinity of the HfO
/Si interface in the case of the irradiation of 2.2 eV SOMB. The oxidation of the Si substrate takes place to generate SiO
compounds. Si atoms were emitted from the SiO
/Si interface region underneath the HfO
overlayers to release the stress generated within the strained Si layers. The emitted Si atoms can pass through the HfO
overlayers and react with the impinging O
gas.
Izumi, Atsushi*; Shudo, Yasuyuki*; Shibayama, Mitsuhiro*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki
Langmuir, 37(47), p.13867 - 13872, 2021/11
Times Cited Count:3 Percentile:14.46(Chemistry, Multidisciplinary)Katsube, Daiki*; Ono, Shinya*; Takayanagi, Shuhei*; Ojima, Shoki*; Maeda, Motoyasu*; Origuchi, Naoki*; Ogawa, Arata*; Ikeda, Natsuki*; Aoyagi, Yoshihide*; Kabutoya, Yuito*; et al.
Langmuir, 37(42), p.12313 - 12317, 2021/10
Times Cited Count:4 Percentile:14.46(Chemistry, Multidisciplinary)We investigated the oxidation of oxygen vacancies at the surface of anatase TiO(001) using supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top-surface and sub-surface could be eliminated by the supply of oxygen using an SSMB. These results indicate that the interstitial vacancies can be mostly assigned to oxygen vacancies, which can be effectively eliminated by using an oxygen SSMB. Oxygen vacancies are present on the surface of anatase TiO
(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the as-grown condition, could also be effectively eliminated using the oxygen SSMB.
Miyazaki, Tsukasa*; Miyata, Noboru*; Arima, Hiroshi*; Kira, Hiroshi*; Ouchi, Keiichi*; Kasai, Satoshi*; Tsumura, Yoshihiro*; Aoki, Hiroyuki
Langmuir, 37(32), p.9873 - 9882, 2021/08
Times Cited Count:7 Percentile:35.84(Chemistry, Multidisciplinary)Aoki, Hiroyuki; Ogawa, Hiroki*; Takenaka, Mikihito*
Langmuir, 37(1), p.196 - 203, 2021/01
Times Cited Count:2 Percentile:9.00(Chemistry, Multidisciplinary)Miyazaki, Tsukasa*; Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Aoki, Hiroyuki; Yamada, Norifumi*; Miyata, Noboru*
Langmuir, 36(49), p.15181 - 15188, 2020/12
Times Cited Count:9 Percentile:32.28(Chemistry, Multidisciplinary)Ito, Kanae; Harada, Masashi*; Yamada, Norifumi*; Kudo, Kenji*; Aoki, Hiroyuki; Kanaya, Toshiji*
Langmuir, 36(43), p.12830 - 12837, 2020/11
Times Cited Count:14 Percentile:51.25(Chemistry, Multidisciplinary)Miyazaki, Tsukasa*; Miyata, Noboru*; Yoshida, Tessei*; Arima, Hiroshi*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; et al.
Langmuir, 36(13), p.3415 - 3424, 2020/04
Times Cited Count:18 Percentile:58.29(Chemistry, Multidisciplinary)Miyazaki, Tsukasa*; Miyata, Noboru*; Asada, Mitsunori*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; Tanaka, Keiji*
Langmuir, 35(34), p.11099 - 11107, 2019/08
Times Cited Count:26 Percentile:66.24(Chemistry, Multidisciplinary)Kobayashi, Taishi*; Nakajima, Shogo*; Motokawa, Ryuhei; Matsumura, Daiju; Saito, Takumi*; Sasaki, Takayuki*
Langmuir, 35(24), p.7995 - 8006, 2019/06
Times Cited Count:6 Percentile:22.02(Chemistry, Multidisciplinary)Motokawa, Ryuhei; Endo, Hitoshi*; Yokoyama, Shingo*; Ogawa, Hiroki*; Kobayashi, Toru; Suzuki, Shinichi; Yaita, Tsuyoshi
Langmuir, 30(50), p.15127 - 15134, 2014/12
Times Cited Count:27 Percentile:60.85(Chemistry, Multidisciplinary)