• Journal of the Society of Disaster Information
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• v.9 no.4
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• pp.449-461
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• 2013

As the hydrofluoric acid leak in Gumi-si, Gyeongsangbuk-do or hydrochloric acid leak in Ulsan, Gyeongsangnam-do demonstrated, chemical related accidents are mostly caused by large amounts of volatile toxic substances leaking due to the damages of storage tank or pipe lines of transporter. Safety assessment is the most important concern because such toxic material accidents cause human and material damages to the environment and atmosphere of the surrounding area. Therefore, in this study, a hydrofluoric acid leaked from a storage tank was selected as the study example to simulate the leaked substance diffusing into the atmosphere and result analysis was performed through the numerical Analysis and diffusion simulation of ALOHA(Areal Location of Hazardous Atmospheres). the results of a qualitative evaluation of HAZOP (Hazard Operability)was looked at to find that the flange leak, operation delay due to leakage of the valve and the hose, and toxic gas leak were danger factors. Possibility of fire from temperature, pressure and corrosion, nitrogen supply overpressure and toxic leak from internal corrosion of tank or pipe joints were also found to be high. ALOHA resulting effects were a little different depending on the input data of Dense Gas Model, however, the wind direction and speed, rather than atmospheric stability, played bigger role. Higher wind speed affected the diffusion of contaminant. In term of the diffusion concentration, both liquid and gas leaks resulted in almost the same $LC_{50}$ and ALOHA AEGL-3(Acute Exposure Guidline Level) values. Each scenarios showed almost identical results in ALOHA model. Therefore, a buffer distance of toxic gas can be determined by comparing the numerical analysis and the diffusion concentration to the IDLH(Immediately Dangerous to Life and Health). Such study will help perform the risk assessment of toxic leak more efficiently and be utilized in establishing community emergency response system properly.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.51-56
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• 1996

The objectives of this study is to find out mechanism of vasodilating effects of ANP in 2K-1C renovascular hypertensive rat aorta and to compare with those of normotensive rat aorta. In 2K-1C renovascular hypertensive rat, average arterial blood pressure and plasma renin activity were higher than in normotensive rat. In 2K-1C renovascular hypertensive rat aorta, NE sensitivity was more increased and maximal contraction of aorta by NE was higher than those of normotensive rat aorta. ANP inhibited NE-induced contraction in both 2K-1C renovascular hypertensive and normotensive rat aorta, concentration-dependently. However, ANP was less effective for relaxing NE-induced contraction in 2K-1C renovascular hypertensive rat aorta than in normotensive rat aorta. ANP inhibited $^{45}Ca^{2+}$ uptake induced by NE in both 2K-1C renovascular hypertensive and normotensive rat aorta. From these results. inhibition of $Ca^{2+}$ influx may be one of the vasodilating mechanism of ANP in 2K-1C renovascular hypertensive rat aorta. Although the potency of ANP in relaxing NE-induced contractions was attenuated, the efficacy of ANP was not changed in 2K-1C renovascular hypertensive rat aorta compared with that of ANP in normotensive rat aorta. Abbreviations: ANP, Atrial natriuretic peptide; 2K-1C, 2-kidney 1 clip; NE, norepinephrine; SHR, Spontaneously hypertensive rat; DOC, Deoxycorticosterone; EDTA, Ethylenediaminetetra-acetic acid; PSS, Physiological salt solution; TRIS, tris(hydroxymethyl) aminomethane

• Childhood Kidney Diseases
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• v.4 no.2
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• pp.102-110
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• 2000

Purpose : Intravenous infusion of albumin has been widely und to relieve severe nephrotic edema in spite of beneficial or harmful effects. The purpose of this study is to examine the harmful effect of albumin on the clinical course of steroid sensitive nephrotic syndrome(SSNS). Method : We prospectively randomized the patients with nephrotic syndrome(biopsy proven or clinically compatible to minimal change nephrotic syndrome) into the albumin group(20$\%$ albumin 1 g/kg) or control group(5$\%$ D/W) between March 1997 and September 1999 at Ewha University Mokdong Hospital. We compared the clinical course of the albumin group(n=13) with the control group(n=13). Results : 1. The duration of steroid therapy until complete remission in the albumin group was significantly longer than the control group($13.7{\pm}6.4\;days\;vs\;7.5{\pm}2.8\;days$)(P<0.05). 2. The remission duration to the first relapse was significantly shorter in the albumin group ($94{\pm}63.5$ days) than the control group($190{\pm}106.4$ days)(P< 0.05). There was no significant difference in the relapse rate within 1 year after complete remission[77$\%$ (10/13) vs 46$\%$ (6/13)](P>0.05) and the relapse frequency per year($1.9{\pm}0.8\;vs\;1.5{\pm}0.5$) between the albumin and control groups. 3. Spot urine protein/creatinine ratio significantly increased in the albumin group at post-albumin 2, 4 days(P<0.05). There was no significant difference in the change of the daily percent weight loss, blood pressure, serum Na, K concentration between the albumin and control groups. Conclusion : Albumin infusion in SSNS delayed the response to steroid and shortened the remission duration to the first relapse. Albumin should be carefully used in nephrotic edema.

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.259-267
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• 2003

Two experiments were conducted to investigate the effect of betaine on egg production, lipid metabolism, and osmoregulation in 18-to 42-week-old ISA Brown laying hens. In experiment 1, three hundred and sixty one hens were fed a com-soy basal diet contailing 16% crude protein (CP), 2800 kcal/kg metabolizable energy (ME), 0.33% methionine, and 0, 300, 600, or 1200 mg betaine per kg diet. Egg production, egg weight, feed consumption, feed conversion, and egg quality were measured every eight weeks. Betaine concentration in live and egg were determined along with serum cholesterol, abdominal fat, total serum protein and albumin levels. In experiment 2, twenty thirty-three-week-old laying hens were fed the same diets as those used in experiment 1 in individual cages and the amount of feed and water consumption were measured for two weeks. At the end of experiment 2, all birds were killed to determine blood plasma and ileal osmopressure, arginine vasotocin (AVT), and liver moisture content. In experiment 1, egg production between the treatments during the first eight weeks were not different, whereas the significant increment of egg production were noticed in the birds fed more than 600 ppm betaine after reaching the peak egg production stage (p<0.05). The egg weight was reduced significantly by the betaine supplementation for the first 8 weeks (p<0.05). Feed conversion tended to improve by betaine supplement. Egg quality was not enhanced by betaine supplementation. Liver betaine level increased with betaine feeding compared to the control but betaine concentration in eggs decreased with betaine supplementation. Betaine supplementation elevated the level of serum total cholesterol and triglyeerides compared to the control. Abdominal fat content was increased by betaine supplementation, whereas liver fat content decreased. In experiment 2, water consumption significantly increased in hens fed diets containing 300 and 600 mg betaine/kg (p<0.05) and osmotic pressure of ileal digesta increased with betaine supplement. Liver moisture content was not affected by betaine, but AVT increased in hens fed betaine. The overal results suggested the possibility of using betaine as a feed additives in the laying hens beacuse of its positive contribution to improving egg production and other metabolic parameters related to lipid metabolism.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.52-60
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• 2006

This study investigated how wood properties (i.e., annual rings, sapwood, heartwood, and cracks) might affect preservative treatment in Japanese larch (Larix leptolepis) round-wood product. We specially focused on small-diameter (~10 cm diameter) wood that is commercially sold in market. Among 100 wood samples, the groups of sample with 13~16, 17~20 annual rings represented 33 and 27 in each frequency, while 2~3 and 4~5 mm annual ring width accounted for 72 and 68 in frequency. More than a half (54%) of wood samples contained a mix of heartwood and sapwood in its surface. The rest (46%) had only heartwood exposed in the wood surface. A wide range of checks were showed in the wood samples, but the highest frequency was observed in samples with 1~6 surface (1~14 mm in size) checks and 1~4 end-grain (8~14 mm in size) checks in each round-wood sample. Pressure treatment resulted in a wide range of penetration of ACQ (Alkaline Copper Quat) into the wood, showing $4.3{\pm}4.19mm$ penetration in the wood samples contained a mix of heartwood and sapwood in its surface. However preservative treatment was much less effective for the heartwood only wood samples, ranging average 1.3 mm with ACQ and 1.1 mm with CCA (Chromated Copper Arsenate). These penetration results shown in heartwood samples did not meet the penetration standard that is required for H3 by the Korean Forest Service in relation to wood preservation treatment. These low penetration results were not significantly improved even if we incised wood samples to improve treatment effect, showing only small increase of 0.7 mm with ACQ and 0.6 mm with CCA. When preservative treatment was tested with heartwood, penetration of preservatives decrease with increase of annual rings per a cross-section area (r=0.5345). We also found that the length and number of check had no effect on preservative treatment, showing r=0.1301 and r=0.1802, respectively.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.593-598
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• 1996

The large number of past investigation on extended myocardial protection clearly indicates that cold potassium cardioplegia and topical cooling have limited capabilities. Accordingly, more recent experimen- tal approaches have focused on the modalities of reperfusion and their implication on postischemic myo- cardial recovery. Oxygen may play a crucial role in the development of ischemic and reperfusion injury. Reactive oxygen radicals may be produced during ischemia or reperfusion after incomplete reduction of molecular oxygen or from other pathway and then induce fatal injury of the heart. The important obser- vation of oxygen-induced myocardial damage during reperfusion has led to the concept of applying oxy- gen free radical scavengers. So, this study is on dietary vitamin C supplementation as antioxidant in rats to determine whether or not they have a higher tolerance against cardiac ischemia-reperf'usion injury under Langendorff system. Male or female Sprague-Dawley rats (190-33Og) were randomly separated into two groups. Group A was not treated(n=10). Group B received vitamin C supplement (n=10). Experiment was performed 24 hours after vitamin C 200mg fed orally as injectable ascorbic acid. There were significant differences in contractile parameters between control and vitamin C-treated group. The RLVP (r te of post/preischemic left ventricular pressure) and Rdp/dt (rate of post/preischemic dp/dt) were significant statistically between two groups (p<0.05). But, RHR (rate of post/preischemic heart rate), time to first beat and sta'utilization were not significant. In conclusion, pretreatment with the antioxidant, ascorbic acid, was found to preserve left ventricular contractile function. But the precise mechanism of action of ascorbic acid has not as yet been determined, so further study will be required.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.579-596
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• 1997

A simulation study was carried out to delineate potential effects of the lake-induced climate change on crop productivity around Lake Imha which was formed after a multi-purpose dam construction in Andong, Korea. Twenty seven cropping zones were identified within the 30 km by 25 km study area. Five automated weather stations were installed within the study area and operated for five years after the lake formation. A geostatistical method was used to calculate the monthly climatological normals of daily maximum and minimum temperature, solar radiation and precipitation for each cropping zone before and after the dam construction. Daily weather data sets for 30 years were generated for each cropping zone from the monthly normals data representing "No lake" and "After lake" climatic scenarios, respectively. They were fed into crop models (ORYZA1 for rice, SOYGRO for soybean, CERES-maize for corn) to simulate the yield potential of each cropping zone. Calculated daily maximum temperature was higher after the dam construction for the period of October through March and lower for the remaining months except June and July. Decrease in daily minimum temperature was predicted for the period of April through August. Monthly total radiation was predicted to decrease after the lake formation in all the months except February, June, and September and the largest drop was found in winter. But there was no consistent pattern in precipitation change. According to the model calculation, the number of cropping zones which showed a decreased yield potential was 2 for soybean and 6 for corn out of 27 zones with a 10 to 17% yield drop. Little change in yield potential was found at most cropping zones in the case of paddy rice, but interannual variation was predicted to increase after the lake formation. the lake formation.

• Journal of Gifted/Talented Education
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• v.14 no.2
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• pp.1-18
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• 2004

This study attempted to survey the present status of the eight students who, 17 years from now, had participated in a special program for 170 days preparing for early entrance to the KAIST. With six students who responded to the questionnaire previously sent, the study focused on each participant's achievement at present, his evaluation on Accelerated Education, his personal opinions on early entrance to university and Gifted Science Education. From the survey, we could find out that three participants had received a doctorate and they are currently working as researchers at research center or professors at university. The other three participants are working as researchers at research center after receiving the M. S. Academic achievements vary according to each participant, but three of them, who ranked high in research achievement, had their articles published in international journals of the SCI level even when they were between 25 and 28 of age. Two of them in particular showed outstanding engineering and developing the commercial modem for IMT 2000 for the first time in Korea. One participant entered Harvard University to major in physics and afterwards studied the law in UCLA. He is now a professor in the law department. Concerning the evaluations on Accelerated Education and early entrance system, four participants answered positively while two participants expressed negative attitudes. When asked their opinions on the Gifted Education in Korea, such problems were pointed out as too much pressure of entering the first-class universities, the tendency to avoid choosing science-related major at universities, the lack of education system that encourages creative thinking, etc. It is necessary that the accelerated education play an important role to maximize their hidden potentials. It remains to be seen in what places these six participants will find themselves and of what ideas they will come up within the next 17 years. It will be worthwhile to wait until then for another survey.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

• Journal of Korean Society of Forest Science
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• v.23 no.1
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• pp.29-33
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• 1974

U-Reuk, a laureate musician in the days of King Jin-Heung, Silla Dynasty, built the Eui Rim Reservoir about 1,400 years ago. This was one of the oldest man-made reservoir. The embankment of the reservoir collapsed by the clumsy artificial drainage on August 19, 1972 when the heavy rainfall of 462 mm/day caused a dangerous overflow of the reservoir. The result of the study on the mystic ancient embankment techniques are as follows: 1. Sandy loam derived from the weathering of granite which is the most widely distributed rock type in the area, was used in the embankment. Large size logs (embankment core) of 30-50 cm in diameter were buried lengthwise along the embankment. 2. The six stocks of Pinus densiflora, 3 stocks of Quercus acutissima, 1 stock of Quercus variabilis and 1 stock of Popolus maximowiczii, altogether 11 stocks are identified. Forest types in the nearby area during the days of the reservoir construction seem to be includde a considerable number of Pinus densiflora, Quercus and Populus species. 3. The angle of repose of the earth materials is taken into account during the embankment. On top of the embankment double layers of clay (20-30 cm indepth) were spread and consolidated. Layer of litter of 20-40 cm in deep covered on the clay layer of the embankment completely, and another layer of clay was consolidated over the litter. Finally, a layer of stones of 10-30 cm in diameter and clay (yellow soil layer) toped the embankment. 4. At the lower part of the embankment clay layer was thicker and became thinner as it goes upwards. At every layer, soil was consolidated and burned. When embankment was completed, it was covered evenly with heavy clay, and finally it was topped with general soil. 5. The heavy clay layer on the inner slope of the embankment showed gray phenomena and litter remained raw humus layer. The clay layer functioned as rubber in the water, and raw humus layer prevented water from seepages. Thus, the embankment was solidly built in this way. 6. The ancient embankment techniques used soils conveyed from nearby area taking the angle of repose into account. Once embankment was completed, clay and litter layers were added to have a plasticity and to withstand the water pressure. 7. It is an excellent technique that the reservoir was constructed with least labor for maximum effects while the recent embankment techniques requires a large amount of labor.