Faculty Profiles - BENINO Yasuhiko

Papers - BENINO Yasuhiko

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Effect of bond valence sum on the structural modeling of lead borate glass Reviewed

Masaaki Nagao, Shinichi Sakida, Yasuhiko Benino, Tokuro Nanba, Atsushi Mukunoki, Tamotsu Chiba, Takahiro Kikuchi, Tomofumi Sakuragi, Hitoshi Owada

Journal of Non-Crystalline Solids 592 2022.9

Publishing type：Research paper (scientific journal)

The structural model of 66.7PbO-33.3B2O3 glass was constructed using a reverse Monte Carlo (RMC) method, in which bond valence sum (BVS) was added as a constraint condition to suppress formation of unrealistic local structures. Based on the crystal structures, the optimal BVS calculating conditions were determined. As a result, BVS distributions with small deviation were successfully achieved without lowering the reproducibility of other experimental constraints. The geometric asymmetry of PbOn polyhedra was evaluated from the eccentric distance between Pb and gravity center of oxygen atoms. The average eccentric distance was shorter than that in the lead borate crystals, indicating less asymmetry of PbOn units in the RMC glass model. The connectivity between BOn and PbOn units was investigated. It was consequently concluded that the glass had a different network structure from the crystal with the same composition, which might be due to the different chemical bonding character between the lead borate glasses and crystals.

DOI： 10.1016/j.jnoncrysol.2022.121751

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Environmental activities on glass in Japan

Tokuro Nanba, Yasuhiko Benino, Tomoko Akai

Journal of the Ceramic Society of Japan 130 ( 8 ) 605 - 610 2022.8

Touch-Cure Polymerization at the Composite Cement-Dentin Interface

K. Yoshihara, N. Nagaoka, Y. Benino, A. Nakamura, T. Hara, Y. Maruo, Y. Yoshida, B. Van Meerbeek

Journal of Dental Research 100 ( 9 ) 935 - 942 2021.8

Publishing type：Research paper (scientific journal)

Ceramic restorations are often adhesively luted onto the tooth prep. The so-called touch-cure concept was developed to yield optimum polymerization of composite cement at the restoration-cement-tooth interface for immediate bond stabilization. Although this touch cure is theorized to initiate polymerization at the interface when the accelerator in the primer makes contact with the cement, this process has not yet been proven. This study aimed to elucidate the mechanism of touch cure by measuring the degree of conversion (DC) of composite cement applied with or without an accelerator-containing tooth primer (TP) versus an accelerator-free primer using real-time Fourier-transform infrared spectroscopy (RT-FTIR) and attenuated total reflection (ATR)–FTIR. Interfacial bond strength was measured in shear mode, the accelerator composition confirmed by X-ray fluorescence analysis (XRF), and the interfacial interaction of TP and composite cement with dentin investigated by X-ray diffraction (XRD), focused-ion-beam scanning electron microscopy (FIB-SEM) with 3-dimensional interface reconstruction, and transmission electron microscopy (TEM). RT/ATR-FTIR revealed the significantly highest DC when the composite cement was applied with the accelerator-containing primer. XRF disclosed a vanadium compound as a novel chemical accelerator within TP, instead of a classic chemical curing initiator system, to set off touch cure as soon the cement contacts the previously applied primer. Although the TP contains the acidic functional monomer 10-MDP for adhesion to tooth tissue, touch cure using the accelerator-containing TP combined the fastest/highest DC with the highest bond strength. FIB-SEM and TEM confirmed the tight interfacial interaction at dentin with submicron hybridization along with stable 10-MDP also Ca-salt nanolayering.

DOI： 10.1177/00220345211001020

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Anisotropic structure of alkali metaphosphate glasses

Seiji Inaba, Yasuhiko Benino, Shinji Kohara, Hideo Hosono, Setsuro Ito

Journal of the American Ceramic Society 103 ( 6 ) 3631 - 3641 2020.6

X-ray fluorescence analysis of carbonate rocks using glass beads

澤田順弘, 紅野安彦, 中尾文彰, 郷津知太郎

地質技術 ( 10 ) 2020

Structural analyses and reverse Monte Carlo modeling of niobium oxide amorphous film prepared by sputtering method Reviewed

SAJIKI Go, BENINO Yasuhiko, OKI Chinatsu, OHARA Koji, OKANO Hiroshi, NANBA Tokuro

Journal of the Ceramic Society of Japan 125 ( 10 ) 760 - 765 2017.10

Language：English Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan

Structural analyses of niobium oxide (NbO_x) amorphous film prepared with a sputtering method have been performed by using synchrotron X-ray radiation at SPring-8. The composition was determined as Nb₂O₅·0.8H₂O from the measurements of Rutherford back scattering, X-ray fluorescence, X-ray absorption near edge structure, and thermal desorption spectroscopy. Structural information was obtained by extended X-ray absorption fine structure and high energy X-ray diffraction measurements. It was supposed from the experimental data that NbO_x consisted of distorted NbO_n polyhedra connected by corner- and edge-sharing. Structural models were constructed with reverse Monte Carlo (RMC) simulations. In the RMC models, the structural characteristics were successfully reproduced, and H atoms were, however, randomly distributed. Then, bond valence sum (BVS) constraint was introduced to the RMC simulation. As the results, narrower distribution in BVS was achieved for all the constituent atoms, and distinct OH bonds were effectively generated in the RMC model.

DOI： 10.2109/jcersj2.17053

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Investigation of electronic structure of amorphous niobium oxide based on the density functional theory calculation of crystalline niobium pentoxide polymorphs Reviewed

OKI Chinatsu, SAJIKI Go, SAKIDA Shinichi, BENINO Yasuhiko, NANBA Tokuro

Journal of the Ceramic Society of Japan 124 ( 12 ) 1221 - 1225 2016.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Ceramic Society of Japan

Electronic structure of amorphous niobium oxide prepared by a sputtering method was investigated based on optical absorption and photoelectron spectroscopies. In the valence band photoelectron spectra, broad peaks without any characteristic components were observed. Then, theoretical calculations based on a density functional theory were performed to interpret the experimental spectra by using three Nb₂O₅ polymorphs. Among the polymorphs, M-phase with tetragonal structure showed better reproducibility than the other B- and R-phases with monoclinic structure. It was finally concluded that the amorphous niobium oxide had a similar electronic structure to M-Nb₂O₅, and it was supposed that the broad feature in the photoelectron spectra was due to the broad distribution of Nb–O bonds in NbO₆ polyhedra, which was characteristic in M-Nb₂O₅.

DOI： 10.2109/jcersj2.16180

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Microscopic structural analysis of lead borate-based glass Reviewed

Atsushi Mukunoki,Tamotsu Chiba,Yasuhiko Benino*,Tomofumi Sakuragi

Progress in Nuclear Energy 91 339 - 344 2016.8

Synchrotron X-ray Scattering Measurements of Disordered Materials Reviewed

Shinji Kohara, Koji Ohara, Hiroo Tajiri, Chulho Song, Osami Sakata, Takeshi Usuki, Yasuhiko Benino, Akitoshi Mizuno, Atsunobu Masuno, Junpei T. Okada, Takehiko Ishikawa, Shinya Hosokawa

ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS 230 ( 3 ) 339 - 368 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WALTER DE GRUYTER GMBH

With the advent of third-generation synchrotron sources and the development of light source techniques, X-ray scattering techniques have become feasible, leading to new approaches for studying the structures of disordered materials in a quantitative manner. We introduce a dedicated diffractometer for high-energy total X-ray scattering measurement and a newly developed anomalous X-ray spectrometer at SPring-8. As advanced methodologies for the measurement of liquids, we now offer three state-of-art levitation instruments for aerodynamic levitation, electrostatic levitation, and acoustic levitation at the SPring-8 beamlines, covering a wide temperature range of -40-3000 degrees C. Furthermore, scientific investigations of glasses, liquids, and amorphous materials reported in the last five years at SPring-8 are reviewed.

DOI： 10.1515/zpch-2015-0654

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Nano-micrometer-architectural acidic silica prepared from iron oxide of leptothrix ochracea origin Reviewed

Hideki Hashimoto, Atsushi Itadani, Takayuki Kudoh, Satoshi Fukui, Yasushige Kuroda, Masaharu Seno, Yoshihiro Kusano, Yasunori Ikeda, Yasuhiko Benino, Tokuro Nanba, Makoto Nakanishi, Tatsuo Fujii, Jun Takada

ACS Applied Materials and Interfaces 5 ( 11 ) 5194 - 5200 2013.6

Language：English Publishing type：Research paper (scientific journal)

We prepared nano-micrometer-architectural acidic silica from a natural amorphous iron oxide with structural silicon which is a product of the iron-oxidizing bacterium Leptothrix ochracea. The starting material was heat-treated at 500 C in a H2 gas flow leading to segregation of α-Fe crystalline particles and then dissolved in 1 M hydrochloric acid to remove the α-Fe particles, giving a gray-colored precipitate. It was determined to be amorphous silica containing some amount of iron (Si/Fe = ∼60). The amorphous silica maintains the nano-microstructure of the starting material - ∼1-μm-diameter micrometer-tubules consisting of inner globular and outer fibrillar structures several tens of nanometer in size - and has many large pores which are most probably formed as a result of segregation of the α-Fe particles on the micrometer-tubule wall. The smallest particle size of the amorphous silica is ∼10 nm, and it has a large surface area of 550 m2/g with micropores (0.7 nm). By using pyridine vapor as a probe molecule to evaluate the active sites in the amorphous silica, we found that it has relatively strong Brønsted and Lewis acidic centers that do not desorb pyridine, even upon evacuation at 400 C. The acidity of this new silica material was confirmed through representative two catalytic reactions: ring-opening reaction and Friedel-Crafts-type reaction, both of which are known to require acid catalysts. © 2013 American Chemical Society.

DOI： 10.1021/am401029r

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Distribution behavior of inorganic constituents in chemical recycling processes of a municipal waste slag Reviewed

Omura Kohei, Sakida Shinichi, Benino Yasuhiko, Nanba Tokuro

Journal of Asian Ceramic Societies 1 ( 1 ) 108 - 113 2013.3

Surface crystallization of stoichiometric glass with Bi₂ZnB₂O₇ crystal using ultrasonic surface treatment followed by heat treatment Reviewed

KANENISHI Keita, SAKIDA Shinichi, BENINO Yasuhiko

Journal of the Ceramic Society of Japan = 日本セラミックス協会学術論文誌 120 ( 1407 ) 509 - 512 2012.11

Effect of additives on the distribution of phosphorus associated with Phase separation of borosilicate glasses Reviewed

120 ( 1407 ) 490 - 493 2012.11

Effect of TiO2 addition on the distribution of phosphorus associated with phase separation of borosilicate glasses

Y. Ohtsuki, S. Sakida, Y. Benino, T. Nanba

Ceramic Transactions 231 145 - 149 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：American Ceramic Society

Behavior of phosphorus associated with phase separation and the effect of TiO2 addition on the phosphorus distribution were investigated in Na2O-B2O3-SiO2 ternary glass system. After heat treatment, phase separation by spinodal decomposition was commonly observed. In the phase separation of TiO2-free glasses, phosphorus was preferentially distributed into B2O3-rich phase, and after TiO2 addition, phosphorus distribution into SiO 2-rich phase was also observed. With increasing TiO2 content, the amount of phosphorus distributed into SiO2-rich phases increased up to 90%. 31P MAS NMR indicated that phosphorus in the glasses was mainly present in negatively-charged Q2 units with terminal oxygen atoms, and in the TiO2-containing glasses, Q 1 or Q0 units containing P-O-Ti bond were confirmed. Despite the formation of negatively-charged Q1 or Q0 units, phosphorus was distributed into SiO2-rich phase, which was due to the distribution of Ti4+ ions with higher coordination numbers acting as network modifiers.

DOI： 10.1002/9781118472590.ch16

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Fabrication and characterization of Er3+-doped tellurite glass waveguides by Ag+-Na+ ion-exchange method using a dry electromigration process

S. Sakida, K. Kimura, Y. Benino, T. Nanba

Ceramic Transactions 231 201 - 207 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：American Ceramic Society

Planar waveguides were prepared on 12Na2O·10NbO 2.5·25WO3·53TeO2·1Er 2O3 ([NbWEr]) substrate glass by Ag+-Na + ion-exchange using a dry electromigration process. The optical properties of the waveguides were characterized and compared with those of [NbWEr] glass waveguides prepared by Ag+-Na+ ion-exchange by thermal diffusion. After ion-exchange by both a dry electromigration process and thermal diffusion, the transmittance of the glasses slightly decreased from that of the [NbWEr] substrate glass but frosting was not observed on these ion-exchanged glasses. The depth of the waveguide fabricated at 300°C by a dry electromigration process was about 8 μm and deeper than that at 380°C by thermal diffusion. On the [NbWEr] glass ion-exchanged at 300°C by a dry electromigration process, the stains seen in the [NbWEr] glass ion-exchanged at 380°C by thermal diffusion were hardly observed. Therefore, the dry electromigration process is promising due to the reduction of the process temperature and fewer stains.

DOI： 10.1002/9781118472590.ch24

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Functional and structural characterizations of fresnoite glass-ceramics oriented with usttechnique

Y. Benino, A. Endo, S. Sakida, T. Nanba

Ceramic Transactions 231 161 - 165 2012

Language：English Publishing type：Research paper (international conference proceedings) Publisher：American Ceramic Society

Transparent glass ceramics with highly oriented surface crystalline layers of fresnoite Ba2TiSi2O8 were prepared by heat treatment of precursor glasses in BaO-TiO2-SiO2 system. The orientation along c-axis of fresnoite crystals normal to the glass surface was evaluated by the surface XRD patterns, and it was remarkably enhanced by ultrasonic surface treatment (UST) before the crystallization using fresnoite powder suspension in water. The effect of UST disappeared after heat treatment in the glass transition region, and the mechanism of UST was discussed on the basis of the persistence at elevated temperatures.

DOI： 10.1002/9781118472590.ch18

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耐火物の耐スラグ侵食性に及ぼす非酸化物添加効果

森田圭輔, 崎田真一, 紅野安彦, 難波徳郎

耐火物 62 ( 3 ) 2010

Correlation between basicity and coordination structure in borosilicate glasses Reviewed

Y. Tanaka, Y. Benino, T. Nanba, S. Sakida, Y. Miura

PHYSICS AND CHEMISTRY OF GLASSES-EUROPEAN JOURNAL OF GLASS SCIENCE AND TECHNOLOGY PART B 50 ( 5 ) 289 - 293 2009.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC GLASS TECHNOLOGY

Various quaternary borosilicate glasses in the general system M(2)O-M'O-Al(2)O(3)-B(2)O(3)SiO(2) (M=Li, Na or K; M'=Ca, Sr or Ba) were prepared, and the concentration of four-fold coordinated boron (B4) atoms was determined using (11)B magic angle spinning NMR. Regression analyses were performed to predict the B4 fraction, in which B4 fraction and glass basicity were used as dependent and independent variables, respectively. Except for Al(2)O(3)-containing glasses, regression formulae giving high correlation coefficients were successfully obtained by using B4/(B+Sixf) (where f is a tunable coefficient) as the dependent variable. As for the glasses containing Al(2)O(3), however, the necessity of a different dependent variable was indicated.

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Molecular orbital calculation of the Si-29 NMR chemical shift in borosilicates: the effect of boron coordination to SiO4 units Reviewed

T. Nanba, Y. Asano, Y. Benino, S. Sakida, Y. Miura

PHYSICS AND CHEMISTRY OF GLASSES-EUROPEAN JOURNAL OF GLASS SCIENCE AND TECHNOLOGY PART B 50 ( 5 ) 301 - 304 2009.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SOC GLASS TECHNOLOGY

Borosilicate cluster models were constructed, and the Si-21 NMR chemical shift was estimated by molecular orbital calculations. For Q(4) species (an SiO4 unit consisting of four bridging oxygen atoms), a higher frequency shift was confirmed due to the replacement of the surrounding SiO4 with BO4 units, and for Q(4) species associated with more than one BO4 unit, the chemical shifts were nearly identical to those for Q(3) species (an SiO4 unit including one nonbridging oxygen) in alkali silicates. The chemical shifts of Q(4) species in borosilicates were interpreted in terms of the change in bond angle of Si-O-(Si,B4) bridges. A change in chemical shift anisotropy of Q(4) species was also found. The Q(4) species associated with two BO4 units indicated an anisotropy maximum, which was smaller than the anisotropy of Q(3) species.

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Molecular orbital calculation of the Si NMR chemical shift in borosilicates: The effect of boron coordination to SiO4 units

T. Nanba, Y. Asano, Y. Benino, S. Sakida, Y. Mima

Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B 50 ( 5 ) 301 - 304 2009.10

Language：English Publishing type：Research paper (scientific journal)

Borosilicate cluster models were constructed, and the 29Si NMR chemical shift was estimated by molecular orbital calculations. For Q 4 species (an SiO4 unit consisting of four bridging oxygen atoms), a higher frequency shift was confirmed due to the replacement of the surrounding SiO4 with BO4 units, and for Q4 species associated with more than one BO4 unit, the chemical shifts were nearly identical to those for Q3 species (an SiO4 unit including one nonbridging oxygen) in alkali silicates. The chemical shifts of Q4 species in borosilicates were interpreted in terms of the change in bond angle of Si-O-(Si,B4) bridges. A change in chemical shift anisotropy of Q4 species was also found. The Q4 species associated with two BO4 units indicated an anisotropy maximum, which was smaller than the anisotropy of Q3 species.

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Papers - BENINO Yasuhiko