• Journal of the Korean Chemical Society
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• v.14 no.3
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• pp.237-242
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• 1970

Effect of Added 1-hexene on the yield of hydrogen produced from Co-60 gamma radiolysis of methanol was investigated at room temperature. The results indicated that the yield of hydrogen decreased rapidly with increasing 1-hexene concentrations. Effect of added methyl borate on the radiolysis of methanol was also studied in the presence of oxygen. The results revealved that methyl borate acted as a less effective scavenger than oxygen towards the precursors of the radiolysis products. Experimental data previously obtained on the systems with oxygen added were treated more quantitatively to re-examine mechanism of the radiolysis of methanol in detail.

• Journal of Photoscience
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• v.8 no.2
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• pp.67-69
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• 2001

Radical cations of DPBEY and PPCB were generated by ${\gamma}$-radiolysis and pulse radiolysis in halogenated solvents. The radical cation PPCB+ shows 505 (shoulder) and 520 nm absorption peaks with 700 ns lifetime in agreement with the laser flash photolysis work and strongly support the exciplex mechanism proposed for the photoreaction of PPCB and dimethylfumarate.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.73-77
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• 1962

Yields of hydrogen, methane, carbon monoxide, formaldehyde and ethylene glycol by gamma-radiolysis of methanol have been determined at room temperature and compared with values reported in the literature. The G-values obtained by the present studies are as follows: $G(H_2)=4.98,\;G(CH_4)=0.28,\;G(CO)=0.09,\;G(HCHO)=2.14\;and\;G(C_2H_6O_2)=3.07.$ The effects of water, methyl borate and alkali halides added to methanol prior to radiolysis have also been investigated. It is observed that alkali iodides and bromides affect the G-values, particularly, of hydrogen, formaldehyde and/or ethylene glycol, whereas alkali chlorides and fluorides have less pronounced effects.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4660-4670
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• 2022

Hydroxyurea (HU) is a novel salt-free reductant used potentially for the separation of U/Pu in the advanced PUREX process. In this work, the radiation stability of HU were systematically investigated in solution by examining the effects of the type of rays (α, β, and γ irradiations), the absorbed dose (10-50 kGy), and the HNO₃ concentration (0-3 mol L^-1). The influence degree on HU radiolysis rates followed the order of the absorbed dose > the ray type > the HNO₃ concentration, but the latter two had moderate effects on HU radiolysis products where NH₄⁺ and NO₂^- were found to be the most abundant ones, suggesting that the differences of α, β, and γ rays should be considered in the study of irradiation effects. The radiolysis mechanism was explored using density functional theory (DFT) calculations, and it proposed the dominant radiolysis paths of HU, indicating that the radiolysis of HU was mainly a free radical reaction among ·H, e_aq^-, H₂O, intermediates, and the radiolytic free radical fragments of HU. The results reported here provide valuable insights into the mechanistic understanding of HU radiolysis under α, β, and γ irradiations and reliable data support for the application of HU in the reprocessing of spent fuel.

• Bulletin of the Korean Chemical Society
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• v.9 no.1
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• pp.55-59
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• 1988

The gaseous carbon dioxide has been irradiated with Co-60 gamma-radiation in the presence and absence of various alcohols, and the radiolysis products analyzed by gas chromatography. Experimental results indicate that no detectable amount of carbon monoxide is formed when pure carbon dioxide is irradiated. By adding small quantities of alcohols to carbon dioxide, however, considerable amount of carbon monoxide, ketones, alcohols and other organic products have been detected. By adding 0.1% of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-l-propanol, 2-butanol, and 2-methyl-2-propanol, G(CO) values obtained are 4.4, 4.5, 5.2, 4.4, 5.2, 5.0, 4.7 and 4.1, respectively. These high yields of carbon monoxide suggest that the oxidation reactions of carbon monoxide may be suppressed by scavenging oxygen atom with the alcohols. The main radiolytic decomposition reactions of the alcohols present in small quantity in carbon dioxide may be supposed to be the reactions with the oxygen atom produced by the radiolysis of carbon dioxide. The decomposition reactions seems to follow pseudo-first order kinetics with respect to the alcohols. The decomposition rate measured with 2-propanol is the fastest and that with 2-methyl-2-propanol the slowest. The mechanisms of the radiolytic decomposition reactions of the alcohols present in carbon dioxide are discussed on the basis of the experimental results of the present study.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.105-113
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• 2006

The oxidizing species are generated from the radiolysis of groundwater in the pore of buffer material around the canister used for the disposal of spent fuels. A mathematical model was introduced to calculate the cathodic current density induced by the oxidant around the canister, which determined the corrosion of carbon steel. An analytical solution was derived to get the cathodic current density in the cylindrical coordinate. The cathodic current densities from both the rectangular coordinate and cylindrical coordinate were compared with each other. The source terms and absorbed dose rate for the calculation of the radiolysis were calculated using the ORIGEN2 and MCNP computer code, respectively. The radius of the canister was determined with the new model in order to prevent the local corrosion. The results showed that the new solution made the cathodic current density around 25 % lower than the Marsh model.

• Journal of the Korean Chemical Society
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• v.9 no.2
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• pp.106-109
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• 1965

The effects of methyl borate, iodine and potassium iodide on the Co-60 gamma radiolysis of methanol have been reinvestigated at room temperature, utilizing an experimental technique based on gas chromatographic determinations of the gaseous products of the radiolysis. The presence of methyl borate reduces the yield for ethylene glycol to some extent, with slight reductions of the yields for hydrogen and formaldehyde. The presence of iodine causes appreciable reduction of the yields for hydrogen, formaldehyde and ethylene glycol, with a slight reduction of the yield for methane. The presence of potassium iodide reduces the yields for hydrogen and ethylene glycol but increases that for formaldehyde. A mechanism of the radiolysis reaction is discussed, on the basis of the observed data.

• Analytical Science and Technology
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• v.21 no.5
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• pp.403-411
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• 2008

Dimethyldibutyltetradecylmalonamide (DMDBTDMA) extractant was used in a solvent extraction process for a radioactive liquid waste treatment. For the study of radiolysis phenomena, DMDBTDMA was synthesized and the degradation compounds (n-methylbutylamine, tetradecane, 1-tetradecanol) in the DMDBTDMA extractant, irradiated with $^{60}Co$ gamma ray, were identified and determined as radiolysis products by a Fourier transform infrared (FT-IR), gas chromatograph/mass spectrometer (GC/MS) analysis and GC/MS with selected ion monitoring (SIM) mode. Retention behavior of n-methylbutylamine, n-dodecane, tetradecane and 1-tetradecanol in the total ion chromatogram with the standard materials and n-dodecane as the internal standard (ISTD) were 2.35 min., 8.83 min., 10.68 min. and 12.75 min., respectively. In the case of tetradecane, there was a linear relationship between the concentration of the tetradecane and the absorbed dose of the ${\gamma}$-ray irradiated DMDBTDMA.

• Journal of Photoscience
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• v.10 no.1
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• pp.121-126
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• 2003

Irradiation of an acetonitrile solution containing dimethylbis(4-vinylphenylmethyl)silane 1a in the presence of 9,10-dicyanoanthracene leads to formation of the intramolecular photocycloadduct, 2-sila-cyclobuta[2.3]cyclophane(2a). In contrast, prolonged irradiation gave insoluble polymeric material. The photocycloreversion of 2a occurs efficiently (quantum yields exceeds unity) by use of redox-type photosensitization in the presence of magnesium perchlorate. The transient absorption spectra generated by pulse radiolysis and gamma-radiolysis show that the radical cation species generated from 1a is different from that arising from 2a.

• Analytical Science and Technology
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• v.18 no.4
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• pp.292-297
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• 2005

The effect of neutron irradiation on the chemical properties was measured in boric acid solution. The pH of the solution decreased in proportion to the irradiation time and the concentration of boric acid. The concentration of hydrogen peroxide, which is one of the radiolysis products of water, is in proportion to the concentration of boric acid, while in inverse proportion to the irradiation time. The oxygen and hydrogen gases had same chemically equivalent ratio in water radiolysis. The lithiun, which comes from $^{10}B(n,{\alpha})^7Li$, had poor relationship with neutron irradiation time at low concentration, $233{\sim}699{\mu}g/mL$, of boric acid, but the relationship was improved at higher concentration.