• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.441-447
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• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.35-39
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• 1992

SMZ is one of the most widely used antibacterial agents in veterinary medicine. It is also used as a growth promotant in many species of domestic animals There are marked species differences in its metabolism and pharmacokinetics. However, its pharmacokinetic and metabolism in rabbits. which are ragarded not only as good laboratorty animals hut also as good economical animals in its own, are lacking. Sex-differences in drug metabolism are well recognized in wide range of animal species including rats. Males are known to he more active than females. It is also know that there are Significant differences in the direction of metabolic pathways. But recently, female goats are reported to be more active in the metabolie capacity of SMZ than the other sex by Dutch researchers at Utrecht. Therefore, it is not easy to make general conclusicn of having higher SMZ metal-die capacity in the male compared to the opposite sex in every animal species. In this regard, the study on metabolic pattern of SMZ in rabbits, which are regarded as hervivorous, is of interest because the dietary habbits of rabbit are comparable to thai of goal, NEW Zealand White rabbits of each sex were given SMZ(35mg/kg) as a bolus injection into the marginalean, vein in order to study its pharmacokinetic profiles(using plasma) anc metabolic pattem(24h urine) as specified in the methods anc materials. 1. In the rabbit, the major metabolic pathway of SMZ was the acetylation(the formation of $N_4AcSMZ$). There were hydroxylation pathways(50HSMZ, $6CH_2OHSMZ$) as well, in the metabolism of SMZ in the rabbit, but minor pathways. 2. No sex differences in the metabolic direction of SMZ and its metabolites formation were found from the urinary excreted metabolites of SMZ out of 24h collected urine. 3. The concentration-time curves of SMZ(35mg/kg, iv) in the plasma compartment were fitted to a one-compartment open model when using a computer program(NONLIN). There was also no difference in the pharmacokinetic pattem of SMZ between two sexes. 4. The emergence of $N_4AcSMZ$ metabolized from SMZ was very fast in the plasma of the rabbit The elimination of $N_4AcSMZ$ was prolonged as compared to that of the parent drug Vie found no sex difference in the elimination pattern of $N_4AcSMZ$ in the rabbit.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.224-243
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• 2014

This study examined the materials and casting technology(cast, alloy, etc.) used in the manufacturing of bronze artifacts based on old literature such as Yongjae Chonghwa, Cheongong Geamul, and The Korea Review. In the casting experiment for restoration of Sangpyong Tongbo, a bronze and brass mother coin mold was made using the sand mold casting method described in The Korea Review. The cast was comprised of the original mold plate frame, wooden frame, and molding sand. Depending on the material of the outer frame, which contains the molding sand, the original mold plate frame can be either a wooden frame or steel frame. For the molding sand, light yellow-colored sand of the Jeonbuk Iri region was used. Next, the composition of the mother alloy used in the restoration of Sangpyong Tongbo was studied. In consideration of the evaporation of tin and lead during actual restoration, the composition of Cu 60%, Zn 30%, and Pb 10% for brass as stated in The Korea Review was modified to Cu 60%, Zn 35%, and Pb 15%. For bronze, based on the composition of Cu 80%, Sn 6%, and Pb 14% used for Haedong Tongbo, the composition was set as Cu 80%, Sn 11%, and Pb 19%. The mother coin mold was restored by first creating a wooden father coin, making a cast from the wooden frame and basic steel frame, alloying, casting, and making a mother coin. Component analysis was conducted on the mother alloy of the restored Sangpyong Tongbo, and its primary and secondary casts. The bronze mother alloy saw a 5% increase in copper and 4% reduction in lead. The brass parent alloy had a 5% increase in copper, but a 4% and 12% decrease in lead and tin respectively. Analysis of the primary and secondary mother coin molds using an energy dispersive spectrometer showed that the bronze mother coin mold had a reduced amount of lead, while the brass mother coin mold had less tin. This can be explained by the evaporation of lead and tin in the melting of the primary mother coin mold. In addition, the ${\alpha}$-phase and lead particles were found in the mother alloy of bronze and brass, as well as the microstructure of the primary and secondary coin molds. Impurities such as Al and Si were observed only in the brass mother coin mold.