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Taguchi, Mitsumasa; Kojima, Takuji
JAEA-Review 2005-001, TIARA Annual Report 2004, p.181 - 182, 2006/01
The yields of OH radicals in water containing phenol have been investigated for several ten MeV/n C ion and Ne ion having the same LET value, as a function of the residual ion energy at the specific depth in water. In this study, beside such energy dependence, the dependence of reaction time of OH radical yield was examined by changing the concentration of phenol as solute. The defferential G'-values of OH radicals, those G-values per kinetic energy of ions increase with specific energy of Ne ions. The G'-value just after irradiation(1.5ns) is relatively high but become lower with reaction time to be the value (2.7) obtained for 
Co 
-rays. It suggests the diffusion behavior of OH radicals locally induced in water.
-nonylphenols in water and elimination of their estrogen activities by Co -ray irradiationKimura, Atsushi; Taguchi, Mitsumasa; Otani, Yoshimi*; Takigami, Machiko; Shimada, Yoshitaka*; Kojima, Takuji; Hiratsuka, Hiroshi*; Namba, Hideki
Radiation Physics and Chemistry, 75(1), p.61 - 69, 2006/01
Times Cited Count：13 Percentile：65.83(Chemistry, Physical)Decomposition of -Nonylphenols (NPs) in water at 1 
mol dm
was decreased exponentially with absorbed dose when NPs were irradiated by Co-rays. Two products having molecular weight of 236, presumably OH adducts of NPs, were detected by LC-MS analyses. The elimination of estrogen activity of aqueous NPs solution including such irradiation products at 5000 Gy (J kg
) was confirmed by the yeast two hybrid assay. These results should expand the application of ionizing radiation to the treatment of NPs.
Solomon, H. M.*; Kojima, Takuji
Nucleus, 33, p.16 - 20, 2005/00
Low-dose dosimeters were developed based on the mixture films of polyvinyl butyral (PVB) and the acid-sensitive dye leucomalachite green (LMG). Chloral hydrate (RX) was added to the mixture for enhancement of the radiation sensitivity of the film dosimeters. Different film dosimeter materials were prepared using 9.07 
10
mole LMG per one gram PVB with various RX:LMG molar concentration ratio. The dosimeter response, which is expressed in terms of change in absorbance at 628 nm per unit thickness, increased linearly with dose and RX concentration. The PVB-LMG dosimeter system, in which the ratio of RX concentration to that of LMG is higher than 10, show measurable dose range of 1-100 Gy for Co -rays.
Mai, H. H.*; Duong, N. D.*; Kojima, Takuji
Radiation Physics and Chemistry, 69(5), p.439 - 444, 2004/04
Times Cited Count：21 Percentile：77.78(Chemistry, Physical)Characteristics of the polyvinyl chloride films containing 0.11wt% of malachite green oxalate or 6GX-setoglausine with 100m in thickness were studied for use as routine dosimeters in radiation processing. These films show basically color bleaching under Co -ray irradiation in a dose range of 5 to 50 kGy. The sensitivity of the dosimeters and the linearity of dose response curves are improved by adding 2.5% of chloral hydrate [CCl
CH(OH)
] and 0.15% hydroquinone [HOC
H
OH]. These additions extent the minimum dose limit to 1 kGy covering dosimetric quality assurance in radiation processing of food and healthcare products. The dose responses of both films at irradiation temperatures of 20-35
C are constant relative to those at 25C, and the irradiation temperature coefficients for 35-55C were estimated to be (0.43 
0.01)%/ C. The dosimeter characteristics are stable within 1% at 25C before and 60 days after irradiation.
Co -ray calibration laboratory for radiation processingTachibana, Hiroyuki; Kojima, Takuji; ; ; Yotsumoto, Keiichi; Tanaka, Ryuichi
Radioisotopes, 48(4), p.247 - 256, 1999/04
no abstracts in English
