• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.17-34
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• 1994

Recently, the photopolymer made of novolak resin as the base and the naphthoquinonediazide(NQD) as the photoreactive compound is used for the presensitized plate(PS plate). The reaction mechanism of the NQD-novolak resin on light exposure is considered. Upon exposure it undergoes a Wolff rearrangement, via ketene intermediate which react with water ti form an 3-indene carboxylic acid. It was also found that NQD type resin in this experiment shows a high relative sensitivity compared with imported sample from Japan.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.411-435
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• 2013

Since catastrophe from explosion of Hukushima nuclear power plant, concerns over possibility of exposure to radioactive matter has been disseminating all over the world and frequent accidents of domestic nuclear power plants also has been amplifying throughout the nation. In the past, major focus was made on compensation for local residents who live nearby nuclear power plants, but focal point of this study is on wage premium of workers who are employed in R&D of nuclear power plants. It is difficult to derive socially desirable result if private sectors are responsible for compensation on workers who suffer from physical damages due to the exposure to radioactive matter. Because victims should verify the damages that occur in the working places. This study conducted a survey on which job would prefer the respondents who are engaged with the nuclear R&D projects as exposure levels to radioactive matter, security of job, location of firms, and work intensity differ. As a result, exposure to radioactive matter was the most important attribute in choosing alternative jobs followed by job security, work intensity and job location. Annual willingness to pay for reduction of exposure to radioactive matter was estimated as 7730~7770 thousand KRW depending on different econometric models. Therefore, Korean government should prepare institutional foundation in order that appropriate compensation should be made on workers who are engaged in R&D projects on nuclear power plants if they have damages from the exposure to radioactive matter.

• Applied Biological Chemistry
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• v.41 no.8
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• pp.578-582
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• 1998

Grape seed oil was characterized to assess the usefulness in the food industry. Among the various oils, the initial antioxidant activity was the highest for grape seed oil. Heating the oil at $180^{\sim}C$ for 20 min retained 86% of the initial activity. Grape seed and sesame oils showed a low peroxide value, about 2, implying a less oxidative reaction. The oxidation of grape seed oil was increased to a less extent by heat-treatment than other oils. Light exposure for 1 month resulted in a slight decrease in the antioxidant activity of grape seed oil, maintaining 96% of the initial activity. Other oils were all light-susceptible and the activities decreased significantly. The peroxide values of all the oils increased by light exposure, but the extent of oxidation was still the least for grape seed oil. The addition of grape seed oil to perilla oil was very effective, in that the peroxide value was 5-times decreased by 1 : 5 composition of grape seed oil versus perilla oil. These results indicate that grape seed oil can be used as a good cooking oil or an additive for other oils.

• Development and Reproduction
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• v.20 no.3
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• pp.255-266
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• 2016

The optimum concentrations of clove oil as an anesthetic for olive flounder (Paralichthys olivaceus) and the stress response of the fish to clove oil anesthesia were determined over a range of water temperatures, and investigated in a simulated transport experiment using analysis of various water and physiological parameters. While the time for induction of anesthesia decreased significantly as both the concentration of clove oil and water temperature increased, the recovery time increased significantly (P<0.05). The plasma cortisol concentration in fish at each temperature increased significantly up to 12 h following exposure (P<0.05), then decreased to 48 h (P<0.05). The DO dissolved oxygen concentrations, pH values, and the fish respiratory frequencies decreased over 6 h following exposure to clove oil in all experimental groups (P<0.05), whereas the $NH_4{^+}$ and $CO_2$ concentrations in all experimental groups increased up to 6 h (P<0.05). The pH values and DO concentrations increased with increasing clove oil concentration (P<0.05) in the 6 h following exposure, and the $CO_2$ and $NH_4{^+}$ concentrations and the respiratory frequencies decreased with increasing clove oil concentration (P<0.05). The results of this experiment suggest that clove oil reduced the metabolic activity of olive flounder, thus reducing $NH_4{^+}$ excretion and $O_2$ consumption. In conclusion, clove oil appears to be a cost-effective and efficient anesthetic that is safe for use and non-toxic to the fish and users. Its use provides the potential for improved transportation of olive flounder.

• Journal of Environmental Health Sciences
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• v.17 no.1
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• pp.79-88
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• 1991

These studies were carried out to find out some characteristic responses of biological samples under the exposure of trace metals. In animal experiment, six rats per week were killed for 6 weeks under Cd exposures and the concentrations of Cd, Cu and Zn in their organs and blood were determined by flame atomic absorption spectrophotometry.The results were summarized as follows: In animal experiments, the concentrations of Cd in the liver and kidney of Cd exposure groups were increased, however, the values of hematocrit and hemoglobin in blood were decreased remarkably. The body weight of the Cd exposure groups showed lower trend than that of control group. The concentrations of Cd in heart, lung and testes were increased slowly during the first 2 weeks. The concentrations of Cd in their organs decreased while the rapid increase of the concentration of Cd in the liver and kidney was observed. While rapid increase of the concentra~ion of Cd in the liver and kidney was observed, the concentrations of Cd in the organs were decreased afterward and increased again while the low increase of the concentration of Cd in the liver and kidney was observed. The concentrations Cu and Zn were increased remarkably in all the organs for first 2 and 3 weeks. In the exposure groups of Cd+Cu and Cd+Zn, the liver and kidney didn't show lower concentration of Cd than that of Cd group.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.7
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• pp.963-968
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• 1998

A study was conducted to investigate the effect of cooling hands of feet on human thermoregulation in the cold. Eight young (22$\pm$1 yr) and eight aged (69$\pm$4 yr) men volun-teered as subjects They stayed at 1$0^{\circ}C$ in the supine posture during the experiment which included hands or feet exposure to the air for 20 minutes. Hand Exposure (HE) and Foot Exposure (FE) were conducted in radomized order and the baseline was kept before HE and FE. Core temperatures, limb skin temperatures adn thermal sensations were measured. Obtained data were analyze using t-test and correlation. Rectal and esophageal tem-peratures increased in the young (YG) and in aged (AG). Change rate of esophageal temperature (Tes) was maintained higher during FE than HE while rectal temperature showed no differences between YG and AG, and between HE and FE. Hand and foot skintemperature in YG and AG decreased similarly during HE and Fe. Forearm skin temperature during HE decreased while leg skin temperature during FE showed no change HE and Fe. It was concluded that the lower cooling. Furthermore, the increase of Tes was greater in young men than aged men. It is also suggested that the wearing behavior can be differently modified between young and aged men.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.388-395
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• 2017

We investigated the toxicity of zinc and aluminum hot-dip galvanized sheet steel to abalone Haliotis discus hannai via changes in the gill and hepatopancreas using histological and transmission electron microscopy analysis. Experimental groups were composed of one control and four exposure conditions (direct or indirect exposure to zinc and aluminum hot-dip galvanized sheet steel). In the control group, aluminum exposure groups (direct and indirect), and indirect zinc exposure group, abalone mortality was not observed until the end of the experiment, and no histopathological changes were observed in the gill and hepatopancreas. However, the direct zinc exposure group exhibited 100% mortality. Ultrastructural analysis of the cytoplasm of ciliated and microvilli-bearing epithelial cells from gill filaments revealed electron-dense vesicles near the cell membrane and disruption of the nuclear membrane. We also observed swollen mitochondria and a loss of mitochondrial cristae. The hepatopancreas showed similar changes, and we detected highly electron-dense particles within the vesicles. These results suggest that abalone exposed directly to zinc hot-dip galvanized sheet steel experience acute toxicity, causing damage to cell organelles in the gill and hepatopancreas and, finally, inducing mortality.

• Journal of radiological science and technology
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• v.47 no.3
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• pp.167-173
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• 2024

This study purpose to establish an appropriate target exposure index(EIT) using dose area product(DAP) and exposure index(EI) based on chest radiography. First, the system response experiment was conducted with radiation quality of RQA5 to compare the dosimetry and dose area product of equipment. Next, EI and DAP were acquired and analyzed while varying the dose in the diagnostic at 70kVp using a human body model phantom. The signal to noise ratio(SNR) of the obtained results was analyzed in the diagnostic with in the diagnostic reference level(DRL) application range. The DRL at percentage 25% had a dose of 0.17 mGy and EI was 83, and at percentage 75% the dose was 0.68 mGy and EI was 344. As the dose increased, the SNR in the subdiaphragm increased. To set the EIT, calibration must first be performed using a dosimeter and set within the DRL range to reflect the needs of the medical institution.

• Journal of radiological science and technology
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• v.43 no.5
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• pp.375-382
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• 2020

PET/CT is a medical equipment that detects 0.511 MeV of gamma rays. The radiation workers are inevitably exposed to ionizing radiation in the process of handling the isotope. Accordingly, PET/CT workers use syringe shields made of lead and tungsten to protect their hands. However, lead and tungsten are known to generate very high scattering particles by interacting with gamma rays. Therefore, in this study, we tried to find out the effect on the scattering particles emitted from the syringe shield. In the experiment, first, the exposure dose to the hand (Rod phantom) was evaluated according to the metal material (lead, tungsten, iron, stainless steel) using Monte Carlo simulation. The exposure dose was compared according to whether or not plastic is attached. Second, the exposure dose of scattering particles was measured using a dosimeter and lead. As a result of the experiment, the shielding rate of plastics using the Monte Carlo simulation showed the largest difference in dose of about 40 % in lead, and the lowest in iron, about 15 %. As a result of the dosimeter test, when the plastic tape was wound on lead, it was found that the reduction rate was about 15 %, 28 %, and 39 % depending on the thickness. Based on the above results, it was found that 0.511 MeV of gamma ray interacts with the shielding tool to emit scattered rays and has a very large effect on radiation exposure. However, it was considered that the scattering particles could be sufficiently removed with plastics with a low atomic number. From now on, when using high-energy radiation, the shielding tool and the skin should not be in direct contact, and should be covered with a material with a low atomic number.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.829-834
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• 2011

Exposure process is the most important technology to fabricate highly integrated circuit. Up to now, mask type lithography process has been generally used. However, it is not efficient for small quantity and/or frequently changing products. Therefore, maskless lithography technology is raised in exposure process. In this study, relations between multi-beam energy and overlay were analyzed. Exposure experiment of generating pattern was performed. It was from presented scan line by multi- beam simulation. As a result, optimal scan line distance was proposed by simulation, and micro pattern accuracy could be improved by exposure experiment using laser direct imaging system.