[en] An understanding of the radiation-induced effects in groundwater is essential to evaluate the safe geological disposal of spent fuel. In groundwater, the bicarbonate ion is the predominant and common anion; this work investigated radiation-induced chemical reactions of (bi)carbonate aqueous solutions with steady-state irradiation and pulse radiolysis methods. Aqueous solutions of sodium (bi)carbonate as high as 50 mmol.dm^-3 were used. The formation of formate, oxalate, and H₂O₂ were measured under different conditions. A complete set of reaction steps and reliable kinetic data for the radiolysis of (bi)carbonate aqueous solutions at ionic strength close to the groundwater were proposed. Kinetic calculations were completed based on the proposed reaction steps and the kinetic data obtained in the present work. The results from the calculation are in good agreement with the experimental results. With these proposed reaction steps and kinetic data, computer simulation can be performed to predict the yield of radiolytic products of (bi)carbonate aqueous solutions as a function of irradiation time and used to evaluate the safety of geological disposal options of spent fuel

[en] Organic heterojunction thin-film transistors are fabricated based on copper phthalocyanine (CuPc) and hexadecafluorophtholocyaninatocopper (F₁₆CuPc) as double active layers, which exhibit typical ambipolar conduction. Several substrate temperatures are utilized to tune film morphology, which results in a remarkable change on the electric characteristics of organic transistors. The highest balanced mobility value of 2.91 x 10^-2 cm²/V s for hole and 1.04 x 10^-2 cm²/V s for electron are obtained by depositing F₁₆CuPc at 150 ^oC and CuPc at 200 ^oC, respectively, which are comparable to those conventional single-layer devices. This result demonstrates that the growth conditions of organic heterojunctions play a crucial role in ambipolar devices.

[en] This paper describes the setup of a high-temperature cell for water pulse radiolysis and the preliminary result of e_aq^- observation. The experiment was performed using D₂O at 25-400 deg. C including supercritical conditions. The e_aq^- formation in supercritical water was confirmed. Temperature dependences of e_aq^- spectrum and Gε_max were investigated. With increasing temperature, it was found that absorption peak shifts significantly to lower energy (red shifting) and Gε_max decreases

[en] Molecular calculations coupled with pulse radiolysis studies are performed to understand the reactions of radicals with caffeic acid. From molecular calculation, we find that e_aq^- and ·OH tend to form adducts with caffeic acid, while N₃^· tends to abstract H from 4-hydroxyl group in benzene ring, generating a semi-quinoid radical. Based on comparison of the heat of formation, the most favorable radical attack sites and the most stable radical structures are predicted. The calculation results suggest that the stability of the electron adducts 9, (6.0±0.4)x10⁷ and (2.0±0.2)x10⁷ M^-1 s^-1, respectively), determined by pulse radiolysis. Molecular calculations seem to be a powerful tool to predict the stability and structures of transient radicals. (author)

[en] The reaction rate constants and transient spectra of 11 flavonoids and 4 phenolic acids reacting with e_aq^- at neutral pH were measured. The results suggest that C₄ keto group is the active site for e_aq^- to attack on flavonoids and phenolic acids, while the o-dihydroxy structure in B-ring, the C_2,3 double bond, the C₃-OH group and glycosylation have little effects on the e_aq^- scavenging activities. (author)

[en] Molecular orbital calculation and pulse radiolysis method are combined in the studies of interaction of caffeic acid with e_aq^-, (CH₃)₂(OH)CCH₂^., CO₂^.-, H^., ·OH and N₃^. radicals. Reaction rate constants, UV-visible spectra of electron|·OH adducts, semiquinone radicals of caffeic ions, and the resulted stable products were derived from experimental data. While the radical attacked sites and the most favorable structures of the transient radicals were predicted by calculation. Reaction mechanisms were proposed. (author)

[en] The interaction of caffeic acid with e_aq^-, (CH₃)₂(OH) CCH₂^·, CO₂^·-, H^·, ·OH and N₃^· radicals were studied by γ-, pulse radiolysis and molecular orbital calculation. UV-visible spectra of electron/·OH adducts, semi-quinone radicals of caffeic ions, and the stable products from the reactions were derived. The rate constants were determined. The attacked sites and the most favorable structures of the transient radicals were predicted. Reaction mechanisms were proposed. (author)

[en] A novel high mobility transparent conductive oxide thin film, tungsten-doped indium oxide (IWO), has been successfully grown on conventional glass substrates by reactive direct current magnetron sputtering technique from a metallic target. Analyses of x-ray photoelectron spectroscopy and x-ray diffraction reveal that tetravalent and hexavalent tungsten ions substitute for trivalent host indium ions without changing the crystalline structure of In₂O₃. IWO thin films were grown with resistivity of 4.4x10^-4 Ω cm, carrier mobility of 52.8 cm² V^-1 S^-1; transmittance exceeding 80% at wavelengths between 380 and 900 nm, and average roughness of 7.5 nm

[en] The author summarizes the research achievements on the following aspects: detection and identification of low molecular radiolysis products of food packaging polymers and degradation products of plastic additives, influences of irradiation atmosphere, dose, dose rate, additives and food simulant on the formation of products, and effects of irradiation on global and specific migration of packaging materials. Some items are suggested to be further studied

[en] Transient radicals (hydrated electron, (SCN)₂^·-, CO₃^·-, etc.) formed in supercritical water have been observed by pulse radiolysis technique. It was found that the spectra and absorption coefficients of the radicals are strongly dependent on the temperature of water and pressure in supercritical water. The G-values of the radical products in water radiolysis tend to increase with increasing temperature up to 400degC. Since it was found that absorption spectrum and molar absorption coefficient of CO₃^·- radical are almost independent of temperature, G-values of OH and e_aq^- would be derived. Then, the absolute values of the absorption coefficients of the radicals would be calculated. Based on above observation, radiolysis of supercritical water is discussed. (author)