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  • Author or Editor: Yoon Yoon x
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Abstract  

Beginning from the premise that research competitiveness at the university level is the starting point for national competitiveness as a whole, this paper analyzes the correlation between university research-related performance and the scholarly or academic resources available through a country’s library system. An analysis of this correlation from two different angles — a macroscopic approach considering universities in OECD nations and a microscopic approach focusing only upon universities in Korea — found that there is indeed a significant correlation between university research performance and the scholarly information available at libraries. A regression analysis of the two approaches also found that the more journal titles subscribed to by university libraries and the higher their budget for materials, the greater the contribution university libraries make to university research competitiveness in Korea as well as other OECD countries. In this light, in order for Korea to reach a level of research competitiveness comparable to other OECD members, policies need to be created that will effectively increase the number of journals subscribed to by university libraries.

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Abstract  

The radon emanation coefficient (ε) from aquifer rock and the Henry’s law constant (H) of radon were determined by measuring activity concentrations using liquid scintillation counter (LSC). For the evaluation of the method, the coefficients were measured at 0, 10 and 20 °C and the temperature dependency of the coefficients was compared with others. The radon emanation coefficients from the rock particles used in this work are 0.0845, 0.1007 and 0.1308 at 0, 10 and 20 °C, respectively. The dimensionless Henry’s law constants for the groundwater used in this work are 0.994, 1.153 and 2.641 at 0, 10 and 20 °C, respectively. The results show a good agreement with those in literatures.

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Abstract  

A method of tritium electrolytic enrichment was developed, optimized and validated. The enrichment parameters were compared with different current and total current charge variation and tritium separation factor was from 8 to 36 with a current density variation. The detection limit of tritium measurement is about 0.5 TU using 1,000 mL sample and 600 min counting time. Several samples of groundwaters were processed in our and another laboratory with good agreement of results within 15% deviation. Developed and validated method of tritium determination was applied groundwaters in Jeju Island with a liquid scintillation counter (LSC) and electrolytic enrichment method using Ni–Ni electrodes. The tritium concentrations in fifty eight groundwaters in Jeju Island were ranged <0.5 TU-3.9 TU and averaged value was 2.12 TU.

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Abstract  

The contents of H-3 and C-14 in groundwater and surface waters around low and medium-level atomic waste repository site in Korea were determined. The concentrations of C-14 were in the range 0.186–0.287 Bq/L. The H-3 concentration of the groundwaters and surface waters were <0.06–5.75 and 1.22–4.74 Bq/L. The average H-3 contents of west, north and south direction were 1.18 ± 0.12, 1.11 ± 0.78 and 2.85 ± 2.66. H-3 and C-14 concentrations in the south direction were relatively higher than west and north direction samples. The surface waters sampled from catchment were four times higher than average H-3 concentration in precipitation. The concentrations of H-3 and C-14 within 5 km area samples were much higher than other samples.

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Abstract  

A radiochemical neutron activation analysis using solvent extraction has been applied for the determination of trace impurities in high purity nickel. Because of the high activity of58Co produced by the nuclear reaction,58Ni(n,p)58Co, cobalt should be separated from the impurities. Removal of cobalt from the other trace elements in the aqueous acidic solution containing 1M thiocyanate ion (KSCN) was achieved by extraction with 1M2-benzylpyridin (BPy) in benzene. From the result of tracer experiments, cobalt was completely separated from most other elements except Fe, Mo and Zn. To determine the experimental accuracy, NIST SRM 673 nickel oxide was analyzed and the results agreed well within 10% deviation. This established radiochemical method was applied to the analysis of high purity nickel samples.

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Abstract  

The source of contaminating high purity silica during grinding process and analytical sensitivity of alpha-emitting impurities have been investigated. To improve the analytical sensitivity for alpha-emitting impurities in grinding high purity silica, a new procedure was studied by employing an irradiation facility in the hydraulic transfer system (HTS) and the nitrogen flushing system. The source of silica contamination was found to be attributed mostly to alumina balls. The detection limit of U and Th in 3N-grade silica samples by neutron activity analysis (NAA) could be improved to a sub-ng/g level. The contamination rates of Th, U, Cl, Fe and Na from the alumina balls were calculated to be 95%, 15%, 15% and 3.5%, respectively.

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Abstract  

A simple method for the determination of the radon emanation fraction was studied using a liquid scintillation counter. The radon activity of the gaseous phase in a closed container was measured 1 day and 35 days after sealing and used to calculate the radon emanation fraction. Radon leakage from the container was investigated using a 226Ra radioactive standard solution (SRM4967, NIST) to plot a radon growth curve. The method was applied to materials that typically contain a high level of radium, such as phosphogypsum, phosphate fertilizer and a rock sample. The effect of temperature on the radon emanation fraction from the materials was investigated at 0, 10, 20, 30 and 40 °C. It was found that there is a linear correlation (R 2 = 0.746 − 0.946) between temperature and the emanation fraction. Within the temperature range, the radon emanation fractions were 0.241–0.466 for phosphogypsum, 0.225–0.351 for phosphate fertilizer and 0.154–0.351 for the rock sample.

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