Papers by Author: K. Ito

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Authors: Chun Qing He, K. Ito, Toshitaka Oka, Yoshinori Kobayashi, Toshiyuki Ohdaira, Ryoichi Suzuki
Abstract: Mesoporous silica films on Si wafers were prepared via a sol-gel process using a triblock copolymer as the structural template. Spin-coated films were dried and subsequently subjected to Ar plasma treatments for decomposing the polymeric porogen. Mesopore formation in the silica film upon Ar plasma treatments was investigated by positron annihilation lifetime spectroscopy. In comparison with calcined silica film, much larger pores, more heterogeneous in size were found in silica film prepared with Ar plasma decomposition of the porogen.
Authors: Kun'ichi Miyazawa, K. Ito, Yuuki Ishida
Authors: Zhe Chen, C. Yin, S. Wang, K. Ito, Q.M. Fu, Q.R. Deng, Z.D. Lin, P. Fu, Y. Zhang, Z.T. Liu
Abstract: In order to enhance the surface anti-fouling property of separation membrane, TiO2/polysulfone (PSF) membrane was prepared by the phase inversion method, and the surface was treated by oxygen plasma to obtain a composite membrane with photo catalysis activity. To evaluate the effect of oxygen plasma on the surface modification, positron annihilation γ-ray spectroscopy coupled with a positron beam was utilized to probe the surface feature, while the catalysis evaluation system was employed to study the anti-fouling activity of the membrane. The results indicate that with increasing plasma treatment time, the membrane exhibits higher S parameter in the lower energies, while the photo catalysis activity is strengthened. It can be concluded that plasma technique can improve the photo catalysis activity of the composite membrane.
Authors: S. Shibagaki, K. Ito, C. Akita, M. Tanaka, Hajime Haneda
Authors: K. Sato, K. Ito, Kouichi Hirata, Run Sheng Yu, Yoshinori Kobayashi
Authors: K. Ito, Hideaki Hagihara, Yoshinori Kobayashi
Abstract: Polypropylene (PP) derivatives, prepared with different α-olefin comonomers of hexane and hexenol, were investigated using the positron annihilation lifetime technique. The free-volume hole sizes for the present polymers were quantified from the long-lived ortho-positronium (o-Ps) lifetimes. In contrast to the case of nonpolar, introduction of the polar hexenol into PP reduced the o-Ps lifetimes and the hole sizes derived from them. This indicates that the interchain interaction due to the hydrogen bonds in the amorphous region is much stronger than the enhancement of the segmental motion due to the butyl long branch. A comparison of the o-Ps lifetimes with the corresponding tensile strength suggested significant contribution of the subnanostructure in the amorphous region to the mechanical property.
Authors: K. Ito, S. Shibagaki, Hajime Haneda, M. Tanaka, S. Shirasaki
Authors: Yu Long Zhang, H. Ichinose, K. Ito, Yuuki Ishida, M. Nakanose
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