• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.221-228
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• 2004

Basic properties of artificial lightweight aggregate by using waste dusts and strength properties of LWA concrete were studied. Bulk specific gravity and water absorption of artificial lightweight aggregates varied from 1.4 to 1.7 and 13 to 16%, respectively. Crushing ratio of artificial lightweight aggregate was above 10% higher than that of crushed stone or gravel. As a result of TCLP leaching test, the leaching amount of tested heavy metal element was below the leaching standard of hazardous material. Slump, compressive strength and stress-strain properties of LWA concrete made of artificial lightweight aggregate were tested. Concrete samples derived from LWA substitution ratio of 30 vol% and W/C ratio of 45 wt% showed the best properties overall. Thermal insulation and sound insulation characteristics of light weight concrete panel with the optimum concrete proportion were tested. Average overall heat transmission of 3.293W/㎡$^{\circ}C$ was observed. It was higher by about 15% than those of normal concrete made by crushed stone. Sound transmission loss of 50.9 ㏈ in frequency of 500 ㎐ was observed. It was higher by about 13% than standard transmission loss.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.965-974
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• 2013

Multiple debris flows occurred on July 27, 2012 in Mt. Umyeon, which resulted in 16 casualties and severe property demage. Accurate reproducing of the propagation and deposition of debris flow is essential for mitigating these disasters. Through applying FLO-2D model to these debris flows and comparing the results with field observations, we seek to evaluate the performance of the model and to analyse the rheological model parameters. Representative yield stress and dynamic viscosity back-calculated for the debris flows in the northern side of Mt. Umyeon are 1022 Pa and 652 $Pa{\cdot}s$, respectively. Numerical results obtained using these parameters reveal that deposition areas of debris flows in Raemian and Shindong-A regions are well reproduced in 63-85% agreement with the field observations. However, the propagation velocities of the flows are significantly underestimated, which is attributable to the inherent limitations of the model that can't take the entrainment of bed material and surface water into account. The debris flow deposition computed in Hyeongchon region where the entrainment is not significant appears to be in very good agreement with the field observation. The sensitivity study of the numerical results on model parameters shows that both sediment volume concentration and roughness coefficient significantly affect the flow thickness and velocity, which underscores the importance of careful selection of these model parameters in FLO-2D modeling.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.2
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• pp.71-81
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• 1987

Nowadays, the high development of industrial technique demands the optimal design of marine structures to be welded under the water, because the underwater welding of the ship hull and marine structures can decrease manpower and cost of production. However there is not available at present any report on fatigue behavior about underwater welded joints. In this paper under tention- tension repeated fatigue stress with frequency of 10 cycles per second by local controlled system, the fatigue strength properties of underwater welded joints of SM41A-2 Plate-to-Plate of 10 mm thickness were experimentally examined. The results obtained were as follows : 1) The fatigue strength of underwater welded joints of SM41A-2 was peaked at the heat input of about 1, 400 joule/mm(180 A, 36 V), while, at the heat input of more than about 1, 100 joule/mm (160 A, 33 V) that of the underwater welds at the higher than cycle of life rather than the lower cycle was higher than that of the base metal but lower than that of the atmosphere welds on account of both cooling and notch effects. 2) The fatigue limit of underwater welds increased with an increase of heat input resulting in a peak of that at the heat input of about 1, 400 joule/mm and then decreased gradually. 3) The fatigue strength at N cycles was peaked between the heat input of about 1, 400 and 1, 700 joule/mm where the strain was rapidly increased. 4) It was confirmed that the optimal zone of heat input condition for obtaining the underwater welds fatigue strength higher than that of the base metal exists, and if out of this zone, the fatigue strength of the underwater welds was lower than that of the base metal because of lack weld penetration, inclusion of slag, voids, etc. 5) By the fatigue test, the underwater welds fractured brittly without visual deformation, so the strain was remarkably less than of the atmosphere welds. 6) The fatigue life factor was peaked at the heat input of about 1, 600 joule/mm (200 A, 36 V) at which the mean strain is a little higher than that of the base metal but quite lower than those of the atmosphere welds, resulting in good underwater welds because both fatigue strength and ductility of the underwater welds are higher than those of the base metal at such heat input.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.651-668
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• 2017

For initial stability of the tunnel, the primary support, Shotcrete and rockbolt shall be placed in the most appropriate time. This is because the role of such support plays a vital role in long-term and short-term tunnel stability. In this study, the rock bolt is an important supporting system that receives the external pressure generated by the stress relaxation during tunnel excavation as axial force and transmits it to the shotcrete on the tunnel excavation surface. Until now, most of the materials of rock bolts have been used in the field, but there have been many problems such as uncertain quality of Chinese materials entering the market, poor packing due to falling down of rock bolts when filled with mortar, and corrosion due to water. Therefore, in this study, we have developed a high strength steel pipe rock bolt using Autobeam material to solve and improve various problems of existing rock bolts. In order to evaluate the performance of the developed bolt, field tests were carried out and the existing mortar filler in order to improve the performance of the rock bolt, the design and construction criteria were studied and the results were included in this paper.

• The Journal of Korean Medicine
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• v.17 no.2 s.32
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• pp.318-330
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• 1996

We had been investigated the effect of ear acupuncture in alcoholics, but in Kang won do province never we have been investigated. so then in Sangji university oriental hospital from Mar. 1. 1995 to Feb. 28. 1996. we clinically analized 102 alcoholics treated The results were summarized as follow: 1. In Age distribution, 40s were the top as 28.4% and next 30s, 50s, 60s 70s, below 3Os. In Sex distribution, these were 92 person in male, 10 person in female. 2. Marrige Status revealed in descending order ; married, single, divorced Sibling order distribution in descending order; eldest son, middle son, youngest son, only son 3. Distribution of education in descending order ; high school, middle school, primary school, collage and graduate school, illiterate 4. Distribution of occupation in descending order; farmer, labor, merchent, salaried and inoccupation, service 5. Distribution of religion in descending order ; none, buddism, protestantism, catholicism 6. Distribution of family history of alcoholism; yes(24.5%), no(69.6%) 7. Distribution of onset of drinking in descending order ; 20s, below 20s, 30s and 40s, 50s 8. Distribution of duration of drinking in descending order ; 20-29 years, 10-19 and below years, 40-49 years, 30-39 years 9. Distribution of the reason of drinking in descending order ; habbit, business and reduce of stress, no reason, syndrome of stop drinking 10. Distribution of frequency of drinking in descending order ; daily, four or five times a week, irregularly, once a week, two or three times a week 11. Distribution of amount of drinking in descending order ; two bottles, one bottle, three bottles, half, bottle above four bottles 12. Distribution of Chief Complaint of Alcohol in descending order ; no appetite and anorexia, diarrhrea insomnia, fatigue, vomitting, tremor, drinking water, hallucination, abdominal pain, constipation 13. Distribution of total MAST score in descending order ; 26-48 score, 13-18 score, 19-25 score, 8-12 score, 0-7 score 14. In the treatment effects according to MAST score, these were complete stop drinking 18.0%, improved 53.0%, unchanged 29.0%. 15. Distribution of liver function test and treatment effects in descending order ; ALAT, ASAT, GGTP, Trigliceride, Alk-phosphatase and Total bilirubin The treatment effects in ear acupuncture were 70.5% effective ones ; stop drinking 17.6%, improved 52.9%. 17. These were headache, nausea, vomitting sense, weakness in revealing symtoms after treatment, but no severe side effect. 18. Distribution of the times of onset in the change of taste in descending order; 3-5 times, below 2 times and above 6 times.

• Journal of Wetlands Research
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• v.13 no.1
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• pp.1-11
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• 2011

A chronic drought stress has been imposed during non-rainy season(from winter to spring) since 1990s. We faced the most significant water crisis in 2001, and the drought was characterized by sultry weather and severe drought on a national scale. It has been widely acknowledged that the drought related damage is 2-3 times serious than floods. In the list of the world's largest natural disaster compiled by NOAA, 4 of the top 5 disasters are droughts. And according to the analysis from the NDMC report, the drought has the highest annual average damage among all the disasters. There was a very serious impact on the economic such as rising consumer price during the 2001 spring drought in Korea. There has been flood prevention measures implemented at national-level but for mitigation of droughts, there are only plans aimed at emergency (short-term) restoration rather than the comprehensive preventive measures. In addition, there is a lack of a clear set of indicators to express drought situation objectively, and therefore it is important and urgent to begin a systematic study. In this study, a nonstationary downscaling model using RCM based climate change scenario was first applied to simulate precipitation, and the simulated precipitation data was used to derive Standardized Precipitation Index (SPI). The SPI under climate change was used to evaluate the spatio-temporal variability of drought through principal component analysis at three different time scales which are 2015, 2045 and 2075. It was found that spatio-temporal variability is likely to modulate with climate change.

• Membrane Journal
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• v.24 no.1
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• pp.10-19
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• 2014

Porous flat sheet membranes for separators in Zn air batteries were prepared with polyethersulfone (PES) solutions by immersion precipitation phase inversion method. PES/polyvinylpyrrolidone(PVP)/N-methylpyrrolidone(NMP) mixtures were used for casting solutions and water was used for coagulant. With the separators, Zn air batteries were fabricated. The separators were characterized by means of stress-strain test, impedance test and SEM. The Zn air batteries were tested by current interrupt method (CIM) and galvanostatic discharge method. The tensile strength increased with increasing PES content in the casting solution while the ionic conductivity decreased. On the other hand, the ionic conductivity increased while the tensile strength decreased with increasing PVP content. The effect of ionic conductivity trend of the separator in the Zn air battery was confirmed through current interrupt method and galvanostatic discharge method experiments. The battery with the separator from casting solution with higher PES content showed higher IR drop and lower discharge capacity. And the battery with the separator from casting solution with higher PVP content showed lower IR drop and higher discharge capacity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.429-441
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• 2011

In the southeast coastal zone of Yellow Sea, the tide characteristics showing ebb-dominant tide and tidal flow were confirmed by analysis of observed tide and tidal currents. Physical factors generating asymmetric tide were reviewed. Influence of bottom shear stress, tidal flat, and nonlinear terms in shallow water equations was investigated by two-dimensional tide modeling. The model results gave good agreements with observed tides, but the amplitude of simulated $M_4$ tide was less than that of observed tide. The tidal flats existing in the study area widely have great effect on the generation of nonlinear tide. The M4 tide is mainly generated near the tidal flats. The deletion of tidal flats prevents the production of the M4 tide. We can conclude that the wide tidal flats is a primary cause of tide asymmetry in the study area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.323-332
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• 1997

Drainage is needed to run off excessive water stress during the rainy season for soybean cultivation in the converted upland from paddy field. This study was conducted to evaluate the effect of planting dates and drainage methods on growth and yield of sprout soybeans in the converted upland from paddy field. The stem and root growth at flowering stage showed no difference by drainage method but plant height, number of nodes and branches, and fresh weight of stem and root were much greater as planting date delayed. Seed yield was correlated positively with fresh weight of stem and root, and T/R ratio at the flowering stage, respectively. Lodging degree was not different by drainage method but was higher in planting at June 16 than May 15. Number of pods and 100 seed weight were not different by drainage method and 100 seed weight was heavy in Eunhakong, light in Kwangankong as planting date delayed. Higher seed yield was observed in surface drainage than open ditched drainage. Yield performance of Eunhakong was good in late planting, while that of Kwangankong was in early planting.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.719-730
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• 2014

The hot water extract from Artemisia capillaris fermented with Hericium erinaceum mycelium (AC-HE) were assessed for the protection against oxidative modification of biological macromolecules and cell death. Antioxidant activity of AC-HE evaluated using 2,2-diphenyl-1-picrylhydrazyl radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical and peroxyl radical scavenging assays. AC-HE showed 61.73% DPPH radical scavenging activity at $500{\mu}g/mL$, 97.39% ABTS radical scavenging activity at $250{\mu}g/mL$, and 44.18% peroxyl radical scavenging activity at $100{\mu}g/mL$. AC-HE were shown to significantly inhibited DNA strand breakage induced by peroxyl radical. AC-HE also prevented peroxyl radical-mediated human serum albumin modification. AC-HE effectively inhibited $H_2O_2$ induced cell death and significantly increased of the 11.47% cell survival at $100{\mu}g/mL$. AC-HE also decreased intracellular reactive oxygen species (ROS) levels in $H_2O_2$-treated cells. The results suggested that AC-HE can contribute to antioxidant and protected cells from oxidative stress-induced cell injury.