[en] A grafting copolymer of starch and acrylamide was prepared by ⁶⁰Co-γ pre-irradiation. After purification, the copolymer was modified by a cationic reaction to form a cationic copolymer. The structure of the cationic copolymer was identified by IR and NMR spectroscopy. Using the industrial and sanitary municipal wastewater from the Factory of Wastewater Treatment of Gaobeidian in Beijing as the study sample, three-treatment methods: flocculation deposition, flocculation deposition combined with γ irradiation and the direct irradiation were carried out. COD was applied to evaluate the treatment effect. The preliminary results show that the method of flocculation deposition combined with γ irradiation was effective than the other two

[en] The period of conversion from alkyl radicals to polyenyl radicals in gamma-irradiated isotactic polypropylene (i.e. PP) is < or approx. 6 days; while in 6.8% APP and 7.6% EPP (APP and EPP are PP containig hexadecane and hexadecene-1, respectively), it was found to be more than 10 days. It was also measured that the initial gelation dose of PP, 6.8% APP, 4.0% EPP and 7.6% EPP are 12.6, 20.7, 30.5 and > 108 Mrad, respectively. This indicates that both of the additives inhibit the radiation crosslinking of PP, and hexadecne-1 shows a stronger effect than hexadecane. It was assumed that hexadecene-1 offers its active allyl H atoms to reduce the radical yield of PP, and then inhibit the radiation crosslinking of PP more strongly than hexadecane. However, the whole mechanism related to the effect of the additives on PP radical connversion needs further research

[en] One-electron reduction of 1,10-phenanthroline-5,6-quinone (PQ) in aqueous solutions was studied by ⁶⁰Co γ-radiolysis using isopropanol free radical as a reductant. The UV/vis absorption spectrum obtained after irradiation at pH9 showed a new broad band centered at 490 nm. Different absorption spectra were obtained at pH ≅ 7 and ≅ 4. Below pH7, the increase in the absorption around 490 nm was much small and decreased with decreasing pH. These observations agree with that in pulse radiolysis experiments where a residual absorption at about 490 nm remained constant for several milliseconds, and this residual absorption increased with increasing pH. It is suggested that the absorption in the visible region observed after the γ-irradiation and millisecond after pulse radiolysis is caused by the same species, a final product. MS analysis indicates that a final product with more mass number that PQ was produced after γ-irradiation at pH 3.3. This final product was assumed to be PQH₂ produced by the disproportionation of PQ semiquinone neutral radical

[en] The paper presents a review of polychlorinated biphenyls (PCBs) radiolysis in polar and nonpolar solvents. The solvated electron capture is the main reaction whether by ⁶⁰Co-γ irradiation or electron beam as the radiation sources. The reactions follow the first or pseudo-first-order kinetics. The products are biphenyls and chloride. (authors)

[en] A leuco dye film dosimeter for dose measurement on ⁶⁰Co gamma radiation processing was developed. The matrix material polyvinyl butyryl (PVB) with leuco malachite green (LMG) and additive halogenated compounds (RX) were manufactured as the PVG dosifilm. Its response (ΔA/L vs dose) at 627 nm showed a linearity (correlation coefficient r>0.999) in the dose range from 0.5 to 80 kGy. The calibration coefficient of temperature during irradiation was +0.053/degree C. The response increased slightly with the increasing of relative humidities (0∼96.4%); and the the calibration coefficient was +0.006/Δr. h(%). From 54.9% to 96.4% the deviation was less than 4%. The PVG dosifilm was stable before and after irradiation when it was stored in the dark at a given relative humidity. The deviation of response on PVG dosifilm kept in a brown desiccator was less than 4% after 40 days. It was suitable to serve as a routine dosimeter

[en] Polyethylene dosifilm for ⁶⁰Co γ-ray and electron beam have been investigated. The dose response of PE film irradiated by electron beam on 5-600 kGy. The slope of curves is 3.488 x 10^-2, the total uncertainty of experiment lower than 10%, the reproducibility of PE film irradiated by γ-ray was better than EB irradiated. There was an inflection point around 55 kGy in γ-ray irradiated case, so the slope is different (i.e. 4.4 x 10^-2). The influence of oxygen and interface were compared and discussed. (author)

[en] A leuco dye film dosimeter for dose measurement on Co-60 gamma radiation processing was developed. The matrix material polyvinyl butyral (PVB) with leuco malachite green (LMG) and additive halogenated compounds (RX) were manufactured as the PVG dosifilm. Its response (Δ A/L vs dose) at 627nm showed a linearity (correlation coefficient r>0.999) in the dose range from 0.5 to 80 kGy. The calibration coefficient of temperature during irradiation was + 0.053/degC. The response increased slightly with the increasing of relative humidities (0-96.4%); and the calibration coefficient was +0.006/Δr.h(%). From 54.9% to 96.4% the deviation was less than 4%. The PVG dosifilm was stable before and after irradiation when it was stored in the dark at a given relative humidity. The deviation of response on PVG dosifilm kept in a brown desiccator was less than 4% after 40 days. It was suitable to serve as a routine dosimeter. (author)

[en] The effect of environmental factors, such as irradiation temperature and relative humidity, on the PVG dosifilm irradiated by EB was tested. Experiments show that the temperature coefficient of irradiated PVG dosifilm was 0.008 deg. C^-1 from 20 deg. C to 55 deg. C, and the humidity coefficient was 0.006 per r.h. (%) from r.h. 0% to 76%. The PVG dosifilm can be used as a routine dosimeter for dose measurement for low-energy EB processing. The absorbed dose values for various irradiation temperature and humidity can be corrected based on experimental data. (author)

[en] The polyethylene film grafted with acrylic acid then dyed with some dyestuffs and produced dyeing polyethylene dosifilm. THe response of ⁶⁰Co γ ray absorbed dose on these films is a linear. The different dose range dependents on different dyestuffs. The effect of temperatrue, relative humidities and irradiation angle during irradiation on the response and the deviation of measurement for these films are studied. The stability of these films before and after irradiation is studied too. The research results show that dyeing polyethylene dosifilm are suitable used as a routine dosimeter in radiation processing with ⁶⁰Co gamma radiation

[en] The grafting reaction of starch-acrylamide by⁶⁰Co γ pre-irradiation was carried out. The grafted copolymer was prepared and identified by IR spectrophotometer. The grafting yield was measured with element analysis. Various influence factors such as absorbed dose, reaction temperature, reaction duration, post-irradiation effect etc. on grafting yield were studied. The grafting yield higher than 80% could be obtained when the grafting reaction was proceeded at 25-30 degree C within 10 minutes after 10 kGy irradiation