• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.44-57
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• 2011

In general, heavy rainfall in Korea is mostly associated with inflow of 850hPa low-level jet. It transports abundant heat and moisture flux to the Changma front. In this study, synoptic characteristics of heavy rainfall in Korea from a case study is examined by classifying heavy rainfall cases with synoptic patterns, in particular distribution of upper- and low-level jets, western North Pacific high, and moisture flux. The surface and upper-level weather charts including auxiliary analysis chart and radar and satellite images obtained from the Korea Meteorological Administration, and 500hPa geopotential heights from NCEP/NCAR are used and then KLAPS is applied to understand the local atmospheric structure associated with heavy rainfall. Results show that maximum frequency in 60 heavy rainfall cases with more than 150mm/day appears in the Changma type of 43 cases (a proportion in relation to a whole is 52%) including the combined Changma types with typhoon and cyclone. As indicated in previous studies, most heavy rainfall cases are related to inflow of low-level jet. In addition, synoptic characteristics based on the analyses of weather charts, radar and satellite images, and KLAPS in heavy rainfall case of 12 July, 2009 reveal that the atmospheric vertical structure in particular equivalent potential temperature favorable for effective inflow of warm and moist southwesterly into the Changma front is linked to large potential instability and the strong convergence accompanied with low-level jet around Suwon contributes to atmospheric upsliding along the Changma front, producing heavy rainfall.

• Journal of the Korean Geotechnical Society
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• v.40 no.3
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• pp.65-75
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• 2024

This study investigates liquefaction-induced settlement through strain-controlled tests using a cyclic direct simple shear device on clean sand specimens. By focusing on the accumulated shear strain, soil density, sample preparation method, and cyclic waveshape, this study attempts to enhance the understanding of soil behavior under seismic loading and its further deformation. Results from tests conducted on remolded samples reveal insights into excess pore water pressure development and post-liquefaction volumetric strain behavior, with denser samples exhibiting lower volumetric strains than looser samples. Similarly, the correlation between the frequency and amplitude variations of the wave and volumetric strain highlights the importance of wave characteristics in soil response, with shear strain amplitude changes, varying the volumetric strain response after reconsolidation. In addition, samples prepared under moist conditions exhibit less volumetric strain than dry-reconstituted samples. Overall, the findings of this study are expected to contribute to predictive models to evaluate liquefaction-induced settlement.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.837-842
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• 2014

A computer program is developed for the prediction of NO generation by the addition of water moisture and water electrolysis gas in LNG-fired turbulent reacting flow. This study is the first part to deal with the moisture effect on NO generation. In this study, parametric investigation has been made in order to see the reduction of thermal NO as a function of amount of moisture content in a LNG-fired flame together with the swirl and radiation effect. First of all, calculation results show that the flame separation together with the NO concentration separation are observed by the typical flow separation due to strong swirl flow. With a fixed amount of air, the increased amount of water moisture from 0 to 10% by 2% interval shows the decrease of NO concentration and flame temperature at exit are from $973^{\circ}C$ and 139 ppm to $852^{\circ}C$ and 71 ppm. The radiation effects on the generation on NO appears more dominant than swirl strength over the range employed in this study. However, for the strong swirl flow employed in this study, the flow separation cause the relatively high NO concentration observed near exit after peak concentration in the front side of the combustor.

• Korean Journal of Plant Taxonomy
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• v.43 no.1
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• pp.34-45
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• 2013

The Polygonum amphibium complex (Poygonaceae) is a highly polymorphic taxon that can grow in aquatic environments as well as in moist terrestrial habitats. Aquatic and terrestrial plants of the P. amphibium complex vary significantly in morphology and exhibit very complicated patterns of morphological variation, resulting in the description of numerous infra-specific taxa. Principal components analysis of 107 individuals of the P. amphibium complex from Asia and North America using 11 morphological characters showed that the aquatic plants can be discerned from the terrestrial plants by leaf size, shape, and petiole length. In contrast, both aquatic and terrestrial plants collected from the same population or locality shared identical sequences in the matK, psbA-trnH IGS, rbcL-accD IGS and trnL-trnF regions of the chloroplast DNA (cpDNA), suggesting that aquatic and terrestrial forms of the P. amphibium complex are not genetically diverged; morphological differences between the two forms are probably due to the differences in environmental conditions of the habitats. In addition, results from the morphological analysis and the maximum parsimony analysis of the cpDNA data set revealed that the plants from Asia including Korea, Japan, China, Mongolia and Russia Far East are diverged from those in North America and Europe, suggesting that the Asian populations should be recognized as a distinct variety, P. amphibium var. amurense Korsh.

• Journal of Aquaculture
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• v.9 no.3
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• pp.255-264
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• 1996

A 15-week growth trial was conducted to evaluate the economical feed formulations for Korean rockfish (Sebastes sehlegeli). Three replicate groups of fish averaging 33 g were fed one of 8 isoproteic ($49\%$) and isolipidic ($8\%$) diets containing various practical ingredients such as fish meal, meat meal, feather meal, blood meal, soybean meal, corn gluten meal, and wheat flour with or without supplemental essential amino acids. A control diet with white fish meal and brown fish meal as the only protein sources was included. Practical ingredients were substituted from $40\%$ up to $65\%$ for portions of the fish meals in the control diet. Essential amino acids (EAA) were added to the diets for balancing EAA composition of each dietary protein source. In addition, these experimental diets were compared with raw fish-based moist pellet containing $50\%$ frozen horse mackerel and $50\%$ commercial binder meal. Results indicated that animal and plant protein sources could substitute for fish meal up to $55\%$ in diet without any adverse effects on growth and chemical composition of fish. Fish growth, body composition, nutrient utilization, and cost of fish production are discussed in relation to nutritional values of the dietary protein sources.

• Journal of Conservation Science
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• v.36 no.5
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• pp.368-382
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• 2020

It was confirmed that a white porcelain figurine in underglaze iron was damaged after exhibition. This study analyzes the current state of salt damage on the artifact and identifies the factors contributing to its deterioration by examining the material characteristics of the artifact and exhibition environment. The analysis will thus assist in preparing a conservation scheme for artifacts. The crystallized carbonate on the surface of the white porcelain figurine is a water-soluble alkali salt with high hygroscopicity and high solubility in water. This solubility increases as the temperature increases. The figurine was low-fired at approximately 1000℃. A lead glaze was applied, and thin cracks were formed on the glazed surface, indicating poor surface properties. Our analysis suggested that the showcase used in the exhibition likely created a moist environment resulting from condensation, as it was exposed to high temperature and relative humidity, particularly in comparison to the exhibition room where the temperature was regulated using an air conditioner. In addition, the artifacts in the showcase were exposed to sudden changes in temperature and relative humidity as the air conditioner was repeatedly turned on and off. Therefore, it can be deduced that the soluble salt remaining on the white porcelain figurine moved toward the surface of the relatively weak glaze as a result of the temperature, and the crystallized salt exacerbated surface damage as the moisture evaporated in a dry environment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.623-629
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• 2001

This study was investigated the quality characteristics of sponge cakes which were prepared b replacing 30% of flour with raw starch and resistant starches, such as, 4 cycled autoclaved-cooled RS 3 maize starch(RS 3), cross-linked RS 4 maize starch (RS 4) was superior to control cake( 100% flour cake). Addition of starches except RS 3 made crust and crumb color lighter and decreased hardness. Especially, cake containing RS 4 had the softest texture. For the adhesiveness and cohesiveness, cake containing RS 4 showed the least changes during 5 storage days. In DSC measurement, cakes containing RS 4 and ARS 4 showed high enthalpy in despite of low hardness. Sensory evaluation showed that cakes containing RS 4 and ARS 4 were significantly moist and soft compared to others. Overall acceptability of cakes containing starch, RS 4 and ARS 4 were evaluated excellent. Therefore, it can be suggested that RS 4 and ARS 4 can be added to the sponge cake for the quality improvement and functional element.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.109-116
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• 2011

This study examined into property of flour dust explosion to get the basic data for safety of industry by protecting accident of dust explosion. The experiment was conducted to know the effect of distance between explodes in the experiment device, effect of flour dust concentration, effect of humidity, effect of explosion pressure to the dust concentration and effect of inactive substance additive. The study indicated that explosion was happened effectively at the optimum distance 100mm or less in inter-polar distance, and minimum ignition energy was measured at 6mm. The data of feed concentration to the probability of explosion showed that the smaller the particle diameter was, the larger probability of explosion was, and the higher the dust concentration was, the more increased the pressure of explosion was, but more than upper limit of dust concentration, then the explosion of pressure decreased. For the effect of humidity, the more it contained water, the more decreased the ignition energy of dust was, so increased minimum explosive concentration, and effective water content was minimum 10% or more. Inactive substance additive was effective in adding more than 15% CaCO3 and CaO as substance inhibiting dust explosion, in which CaCO3 was more effective than CaO. the analysis of the flame of dust explosion was performed by high-speed video camera, it showed the size of flame bacame smaller in order that sub feed, main feed, wheat powder. As a result, sub feed was expected to be less dangerous than others.

• Culinary science and hospitality research
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• v.22 no.8
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• pp.226-234
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• 2016

In this study, the possibility of developing new type of yanggaeng has been reviewed by evaluating physio-chemical and sensual characteristics of new yanggaeng products using 5~20% of powder of plantain that is a hardy plant resource from most of hillside in Korea. The moisture contents of plantain powder was 1.9%, DPPH radical scavenging ability was 15.67 mg/mL, and total polyphenol contents was 7.00mg/g. By increasing the adding rate of plantain powder the moisture contents and pH of yanggaeng were decreased. From chromatography, by increasing the adding rate of plantain powder the brightness, L-value was decreased along with redness, a-value, yellowness, and b-value. The a-value of sample group adding 5% of plantain powder was the highest and that of sample group adding 20% was the lowest (p<0.001). From texture measurement shown that the hardness of sample group adding 5% of plantain powder was the highest by 3,937.04 and that of sample group adding 20% of plantain powder was the lowest by 2,153.59. The springiness of sample group adding 5% of plantain powder was the highest by 6.79% and that of sample group adding 20% of plantain powder was the lowest by 4.76%. The cohesiveness of sample group adding 20% of plantain powder was the lowest by 177.35 and it was significant (p<0.001). The result of sensory test showed that sample group adding 10% of plantain powder achieved the highest appraisal from most factors, such as color, scent. sweetness, chewiness, moist level, softness level and total preference. As shown from the above results, the sensory preference of yanggaeng can be improved by adding proper volume of plantain powder while making it, so it is understood that the addition of plantain powder in making yanggaeng would give better possibility in commercialization. By considering sensory preference factor the 10% addition rate of plantain powder while making yanggaeng would be the most proper recipe.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.463-471
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• 2006

Electrical resistivity surveys were conducted at areas of abandoned landfills in Cheonan and Wonju. Geology and extent of leachate migration around the landfills were evaluated with collected resistivity data by 2-D and 3-D resistivity inverse modeling. The Cheonan landfill is located above the paddy fields and the resistivity survey lines were crossed to examine possible pollution at the paddy fields by leakage of the landfill leachate. In Wonju, the landfill and the downgradient paddy fields are divided by a concrete barrier wall. At the bottom of the landfill, there is a leachate settlement system, which has not been in operation. To evaluate leachate leakage into the paddy fields, a total of 4 survey lines were used. According to the resistivity survey results, the landfill leachate in Cheonan appeared to be restricted only within the interior of the landfill, not to migrate into the subsurface of the paddy fields. These results are well consistent with electrical conductivity values of groundwaters obtained from a periodic analysis of water qualities. In Wonju, however, it was inferred that the leachate emanating from the landfill migrated beneath the abandoned leachate settlement system and the leachate would reach the downgradient paddy fields. Low resistivity area was observed in the old reservoir area and it appeared to be derived from convergence of groundwater flows from the surrounding valley and the moist wet land. In addition, groundwater flow into the paddy fields occurs beneath the old reservoir embankment at depths of $7{\sim}8m$. This paper reports details of the resistivity surveys for the uncontrolled landfills.