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-irradiations in terms of turbidityYamashita, Shinichi; Hiroki, Akihiro; Nagasawa, Naotsugu; Taguchi, Mitsumasa
no journal, ,
Polymer gel dosimeters based on hydroxypropylcellulose (HPC) hydrogel crosslinked by an irradiation of 2-MeV electron beam have been developed. Gel properties of the radiation-crosslinked HPC hydrogel were estimated with varying HPC concentration, absorbed dose, and type of radiation. Such hydrogel was utilized as gel matrix for polymer gel dosimeters which are more environment-friendly and easily handled than "toxic" polymer gel dosimeters composed of methacrylic acid or acrylamide. In the present study, solutes of the gel dosimeters were 2-hydroxyethyl-methacrylate (HEMA), polyethylene glycol dimethacrylate (PEG), and tetrakis hydroxyphosphonium chloride (THPC). Ratio of the concentrations of the solutes was varied to investigate sensitivity from the viewpoint of absorbance in a UV-vis region. As a result, absorbance increase in shorter-wavelength region (i.e. 300-500 nm) was different from that in longer-wavelength region. It was found that a peak appears in 300-400 nm with about 4-Gy irradiation, which is thought to be corresponding to productions of microgels, and that this peak slightly shift to longer wavelength with further irradiation.
Yamaguchi, Makoto
no journal, ,
no abstracts in English
Hiroki, Akihiro; Sato, Toshihiro*; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Tamada, Masao
no journal, ,
Modification of mechanical properties of hydroxypropyl cellulose (HPC) gels by radiation crosslinking with functional monomers was investigated. The modified HPC hydrogels were prepared by electron beam irradiation to highly concentrated aqueous solutions containing HPC, 2-hydroxy methacrylate (HEMA) and tricosaethylene glycol dimethacrylate (23G). Tensile strength and elongation at break of HPC/HEMA/23G hydrogel (20/2.0/0.2 wt%) obtained at 50 kGy were 2.0 kg/cm
and 124%, which exhibited about 2.0 times larger than these of the pure HPC hydrogel. Therefore, the HPC hydrogels with desired properties were obtained by radiation crosslinking HPC with monomers.
Iwamatsu, Kazuhiro*; Taguchi, Mitsumasa; Sugo, Yumi; Kurashima, Satoshi; Katsumura, Yosuke*
no journal, ,
no abstracts in English
Asano, Masaharu; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Yamamoto, Kazuya*; Sampei, Fumihiro*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*
no journal, ,
We prepared anion-exchange membranes based on an ethylene-tetrafluoroethylene copolymer by -ray-induced graft polymerization of chloromethylstyrene (CMS) and the subsequent quaternization reaction. The crosslinker effect was investigated in terms of membrane preparation and performance of a hydrazine fuel cell. The quaternization ratio appeared to decrease as the concentration of divinylbenzene (DVB) in the CMS grafting solution increased. Importantly, the crosslinker lowered the water uptake of the resulting membranes in the Cl and OH forms, possibly thereby restricting excessive swelling during the fuel-cell operation.
Tran, D. T.; Sawada, Shinichi; Hasegawa, Shin; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
no journal, ,
We investigated the hierarchical structures of poly(ethylene-co-tetrafluoroethylene) (ETFE) based polymer electrolyte membranes (ETFE-PEMs) by comparison with those of precursor original ETFE and styrene-grafted (grafted ETFE) films using small-angle X-ray scattering (SAXS). The ETFE substrate has a lamellar structure with d-spacing of 23.1 nm, while grafted ETFE and ETFE-PEMs showed shoulder peaks at lower Q values, corresponding to d-spacing of 32.7 and 36.1 nm. The grafted ETFE and ETFE-PEM showed new peaks at larger Q value regions, corresponding to d-spacing of 0.94 and 1.48 nm, respectively. These peaks should be ascribed to internal structures of grafted polymers and ion channels.
Hirade, Tetsuya; Oka, Toshitaka; Morishita, Norio*; Idesaki, Akira; Shimada, Akihiko
no journal, ,
Ortho-Ps is an unique probe that the lifetime can give information of microscopic free volume in polymers. Although it is often used for polymer researches, there is no Ps formation in polyimide polymers such as Kapton. Therefore we tried to study the change of free volume of irradiated Kapton by use of a new idea that the change of free volume can be observed by the change of free positron annihilation lifetime. The change of free volume in irradiated Kapton could be discussed by observing the free positron annihilation lifetime instead of ortho-Ps annihilation lifetime.
Nagaishi, Ryuji; Kumagai, Yuta; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
no journal, ,
Radioactive water has been emitted following incidents at the Fukushima Dai-ichi Nuclear Power Station, and needed to be quickly decontaminated by the adsorption and/or the coagulation sedimentation of radioactive nuclides, where hydrogen molecules are produced by water radiolysis. The decontamination process with zeolites as absorbents of radioactive cesium was assumed, the observed yields of hydrogen production determined in mixtures of seawater and zeolite, and then the production rates estimated for the safety operation of process before the operation started.
Shimada, Akihiko; Kudo, Hisaaki*; Seguchi, Tadao*; Tamura, Kiyotoshi; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito
no journal, ,
no abstracts in English
, Br
, Br
in aqueous solutions at elevated temperaturesLin, M.; Muroya, Yusa*; Katsumura, Yosuke*; Archirel, P.*; Van-Oanh, N. T.*; Nagaishi, Ryuji; Kumagai, Yuta; Mostafavi, M.*
no journal, ,
The temperature dependent absorption spectra of Br, Br and Br have been investigated by pulse radiolysis or steady-state irradiation. The spectra of Br and Br exhibit almost no shift at the absorption maximum, while that of Br shows a red-shift with increasing temperature. Quantum chemical calculations have been also performed to unveil the nature of the spectral shift of Br.
Lin, M.; Muroya, Yusa*; Katsumura, Yosuke*; El Omar, A. K.*; Mostafavi, M.*; Meesungneon, J.*; Jay-Gerin, J.-P.*
no journal, ,
Picosecond pulse radiolysis measurements using a pulse-probe method are performed to measure directly the time-dependent radiolytic yield of hydroxyl radical in pure HO and DO. Special attention has been paid to the contribution of the absorption by the irradiated empty fused silica cell in UV.
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi
no journal, ,
no abstracts in English
Kumagai, Yuta; Nagaishi, Ryuji; Yamada, Reiji; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
no journal, ,
The amount of hydrogen produced in -radiolysis of mixture of seawater and mordenite was studied. The measured yield was decreased with decrease in the weight fraction of seawater. However, the yield was not simply proportional to the weight fraction of seawater and the influence of the mordenite was observed as additional production of hydrogen. At a weight fraction of seawater more than 0.2, the measured amount of hydrogen could be explained by an empirical equation given by a liner combination of two hydrogen production terms representing hydrogen production due to the energy deposition to seawater and that to mordenite. Each of the terms was expressed as a product of the absorbed energy and a yield given as the proportionality coefficient, and each of the yields could be a constant independent of the mixture ratio. The result imply an instinctive explanation of hydrogen production from the mixture of solid and liquid using the two respective yields.
Kondo, Takafumi*; Yang, J.*; Yoshida, Yoichi*; Nagaishi, Ryuji; Taguchi, Mitsumasa; Takahashi, Kenji*; Kato, Ryuji*
no journal, ,
no abstracts in English
Fujii, Kentaro; Yokoya, Akinari
no journal, ,
We have investigated the change of the spectra of the X-ray absorption near edge structure (XANES) of DNA exposed to monochromatic soft X-rays. We used calf thymus DNA thin films as samples and observed N K-shell and O K-shell XANES spectral changes. The typical monochromatic soft X-ray energies used for the irradiation (380, 435, 560, and 760 eV) were obtained from SPring-8, BL23SU. The observed spectra show the deprotonation from nucleobase and the decomposition of sugar site of the DNA by irradiation. By comparing the spectral changes in XANES with the yields of base lesions and strand breaks, we will discuss the molecular structure of DNA lesions by soft X-irradiation.
Ito, Hisayoshi; Seko, Noriaki; Kuroki, Ryota; Yaita, Tsuyoshi; Naganawa, Hirochika; Nakayama, Shinichi
no journal, ,
For removing radioactive elements scattered in environment due to nuclear plant accident, we have synthesized highly efficient cesium absorbents by introducing phosphomolybdic acid groups into polyethlene matrix with radiation grafting. Cesium absorbents based on protein or crown ether materials have been newly developed. We have also established immobilization and collection technology of cesium existed into the soil outer layer by using polyion and bentonite (clay). The effectiveness of these technologies has been demonstrated from the field examination in Fukushima.
Saiki, Seiichi; Puspitasari, T.*; Seko, Noriaki
no journal, ,
no abstracts in English
Ma, H.; Hoshina, Hiroyuki; Seko, Noriaki
no journal, ,
In this paper, a pre-irradiation method was used for emulsion graft polymerization of 4-hydroxybutyl acrylate glycidylether (4-HB) onto polyethylene/polypropylene (PE/PP) nonwoven fabric (NF). The degree of grafting (D
) which can be calculated by weight increment was determined as a function of reaction time, irradiation dose, and monomer concentration. After 30 kGy irradiation, with 4-HB concentration of 5%, surfactant Span 20 of 0.5% at 40 
C for 2 h, the trunk polymer was made grafted at a D of 135%. After modified by ethylenediamine (EDA) the 4-HB-grafted PE/PP nonwoven fabric showed high adsorption capability of Cu
, Pb and Zn. Compared with glycidyl methacrylate (GMA) which is a typical functional monomer for graft polymerization, 4-HB-grafted adsorbent exhibited not only better mechanical property but also higher adsorption capacity of Cu and Pb.
Oka, Toshitaka; Yokoya, Akinari; Fujii, Kentaro
no journal, ,
no abstracts in English
Katsumura, Yosuke; Yamashita, Shinichi; Hirade, Tetsuya; Matsuura, Chihiro*; Iwamatsu, Kazuhiro*; Taguchi, Mitsumasa
no journal, ,
no abstracts in English