• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.596-602
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• 1994

To separate and concentrate mucilage from yam(Dioscorea batatas DECNE), yam was dried, microparticulated using impact mill and air-classified at different air classifying wheel speed(ACWS) in classifier. As ACWS increased from 5,000 rpm to 22,500 rpm, the contents of dietary fiber, protein and lipid of air classified microparticles(ACM) increased remarkably. Especially the ACM with ACWS over 15,000 rpm showed 36.41% dietary fiber and 16.66% protein. The dietary fiber and protein components were concentrated to $2.5{\sim}9.0$ times as compared with whole yam powder. Concomitantly the non-fibrous carbohydrate decreased from 88.31% to 16.84. The damaged starch(%), WSI and WAI of ACM of ACWS over 15,000 rpm were $1.5{\sim}3.0$ times higher than those of ACM under ACWS 15,000 rpm. The apparent viscosity of ACM was 0.0800 Pa s over ACWS 15,000 rpm and 0.0080 Pa s under ACWS 15,000 rpm. Judging from viscosity of ACM, the mucilage component of yam was concentrated to 10 times. In conclusion, the optimum process to separate and concentrate the mucilage from yam consisted of the microparticulation to $5{\sim}30{\mu}m$ and the air-classification at ACWS over 15,000 rpm.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.4
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• pp.81-89
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• 2009

The seepage should be analyzed to design or reinforce the levees. The steady seepage analysis is an usual application in USA and European countries where the large scaled dams and levees are existed. However, Korea and Japan, where the reaching time is short, the excessive forces are applied on the levees at the short reaching time if the seepages are analyzed in steady condition. Accordingly, the unsteady analysis based on the variation of time is necessitated. In the unsteady analysis, the flood wave type is necessary. No criteria and standards, however, are derived for the unsteady seepage in Korea. In the study, the flood wave type is derived for the unsteady seepage. The major reliable flood surface data are collected in 5 stations including Jindong of the Nakdong river basin. The data are sorted in duration, and they are non-dimensionalized. The statistical method is also applied to derive the waves. To verify the study, the seepage is analyzed by the derived wave and applied to the prototype. The results are also compared with the Japanese Method. The errors between the hydraulic gradient and critical velocity method are $0{\sim}0.7%$, $0{\sim}0.7%$ at the Jindong, $1.6{\sim}4.0%$, $1.7{\sim}4.1%$ at the Hyunpoong, $0.6{\sim}3.6%$, $0.6{\sim}3.7%$ at the Waegwan, $2.0{\sim}8.1%$, $2.0{\sim}8.1%$ at the Nakdong, and $1.2{\sim}9.8%$, $1.3{\sim}9.9%$ at the Jeongam, respectively. The relationship($R^2$) between each method is relatively high as $0.983{\sim}0.999$. This means the results are more logical than the Japanese method, and the study is applicable to the design of hydraulic structures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.600-604
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• 2001

For the effective utilization of cuttle bone as a calcium powder, we examined calcination condition ($700^{\circ}C: 0\sim10\;hrs,\;800^{\circ}C:\;0\sim3\;hrs,\;900^{\circ}C:\;0\sim1\;hr\;and\;1,000^{\circ}C:\;0\sim30\;mins$) for recovery of calcium from raw cuttle bone powder (RCB) and characteristics of calcined cuttle bone powder (CCB) treated by optimal condition. During calcination of RCB, the yields was decreased, while total and soluble calcium contents and white index were increased up to constant calcination time ($8\;hrs\;at\;700^{\circ}C,\;2\;hrs\;at\;800^{\circ}C,\;45\;min\;at\;900^{\circ}C\;and\;20\;min\;at\;1,000^{\circ}C$). But, these after that almost unchanged. From these results, the optimal calcination conditions for recovery of calcium from RCB were revealed $8\;hrs\;at\;700^{\circ}C,\;2\;hrs\;at\;800^{\circ}C,\;45\;min\;at\;900^{\circ}C\;and\;20\;min\;at\;1,000^{\circ}C$. In the case of CCB treated for 2 hrs at $800^{\circ}C$, total calcium was about $70\%$, the major component was calcium oxide, and the structure consisted of porosity. The calcium solubility of CCB increased by 22 times compared to RCB. But, the pH of RCB was about 12.9. Therefore, for the effective utilization of RCB as a calcium powder, it requires a suitable modification operation for adjustment of pH ($pH\;2.0\~9.0$).

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.128-137
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• 2005

In this study we measured the amount of light energy that was projected through the tooth material and analyzed the degree of polymerization by measuring the surface hardness of composites. For polymerization, Optilux 501 (Demetron, USA) with two types of light guide was used: a 12 mm diameter light guide with 840 nW/$cm^2$ light intensity and a 7 mm diameter turbo light guide with 1100 nW/$cm^2$. Specimens were divided into three groups according to thickness of penetrating tooth (1 mm, 2 mm, 0 mm). Each group was further divided into four subgroups according to type of light guide and curing time (20 seconds, 40 seconds). Vickers' hardness was measured by using a microhardness tester. In 0 mm and 1 mm penetrating tooth group, which were polymerized by a turbo light guide for 40 seconds, showed the highest hardness values. The specimens from 2 mm penetrating tooth group, which were polymerized for 20 seconds, demonstrated the lowest hardness regardless of the types of light guides (p < 0.05). The results of this study suggest that, when projecting tooth material over a specified thickness, the increase of polymerization will be limited even if light intensity or curing time is increased.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.2
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• pp.1-14
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• 2017

The purpose of this study is to understand the environmental traits and significance of the pond place that appears in historic maps in 'Dongchon(東村)', which is the eastern section within the fortress wall of Hanyang. We reviewed various documents and maps to identify the name of the pond, and of those materials we followed the name provided by official national records and geographical titles to designate it 'Eouidongji Pond(於義洞池).' The results of the research showed, first, that from the standpoint of location and environmental characteristics, that the area of the Eouidongji Pond was an area that contained a pastoral atmosphere within the city. It was located in an area where the waters flowing from the mountains gathered, and the boundaries of the pond would change based on water levels within a plot of land about 2,000pyeong(app. $6,600m^2$) in size. Second, when seen from the perspective of its creation background, the Eouidongji Pond seems to have been a naturally occurring pond which was modified when the water system was managed in the city at the beginning of the dynasty. In addition to its role as a reservoir, it was operated as a lotus pond(蓮池) to offer lotus(蓮) related by-products. With the nearby detached palace being actively used, it seems the pond was managed at the same time. The pond had already been filled in by the early 20th century, and although there were efforts to reconstruct the pond, it was eventually destroyed as the area was included in the site of a school during the colonial period. Third, the Eouidongji Pond was appreciated in many cases by individuals or admired as part of the natural landscape by viewing it from afar. In addition, it provided entry landscape near the road entering Dongchon, and was a location that was easily visited in connection with other nearby pleasure grounds. Through studying the location and environmental characteristics, the background of its creation and destruction, operation and management by time period, usage at the time, and characteristics of scenery appreciation of Eouidongji Pond, the Eouidongji Pond was a pond of high practical value to the nation, as it supplemented the water system in the city and was able to provide lotus harvests for the nation. In addition, from a urban environment perspective, it was a lateral landmark with a large area, as well as an effective boundary. It was an open area that the people of the Hanseong-bu could freely use, and it had a high public value due to its ease of accessibility.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.345-351
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• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.3
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• pp.237-249
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• 2016

In this study, the antioxidant effect of Chungkukjang supplementation against memory impairment and oxidative stress in scopolamine (2 mg/kg i.p)-injected mice was investigated. The experimental animals were divided into five groups and fed experimental diets for 12 weeks; normal diet group (C), scopolamine + normal diet group (S), scopolamine + 63.0% soybean Chungkukjang supplementation group (SS), scopolamine + 45.0% Yakkong Chungkukjang supplementation group (SY), and scopolamine + 50.0% black foods such as black rice, black sesame seeds, and sea tangle added Yakkong Chungkukjang group (SYB). For the results of food intake, body weight gain, and brain weights, levels of scopolamine-injected groups were lower than the levels of the control group. The reduced brain weight of the scopolamine-injected group (S) was regulated to control level by supplementation of three types Chungkukjang. In the oxidative stress indicator, nitric oxide and malondialdehyde levels in serum of scopolamine-injected mice were higher than those of other groups. However, supplementation of soybeans, Yakkong and black foods added Yakkong Chungkukjang was proven to regulate them. Antioxidant enzyme activities such as superoxide dismutase (SOD) and glutathione-S-transferase (GST) in serum showed no significant differences among the groups. The reduced levels of vitamin A and vitamin E in serum and brain tissue of scopolamine-injected mice were controlled by supplementation of three types of Chungkukjang. Total antioxidant capacity (TAC) of scopolamine-injected group was lower than those of other groups. However, TAC was significantly elevated by Chunggukjang supplementation. Therefore, antioxidative effects of soybeans, Yakkong, and black foods added Yakkong Chungkukjang supplementations against oxidative stress in scopolamine-injected in mice could expected.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.471-484
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• 2009

This study was carried out to classify vegetation structure on the deciduous forest at Namdeogyu area in Deogyusan National Park from May 2007 to September 2008 using the gradient analyses and phytosociological method. The vegetation was classified into Quercus mongolica community(Typical subcommunity, Rhododendron sehlippenbaehii-Q. mongolica subcommunity, Carex lanceolata-Q. mongolica subcommunity), Q. Serrata community(Typical subcommunity, Q. variabilis -Q. serrata subcommunity, Carpinus laxiflora - Q. serrata subcommunity), C. laxiflora community, Fraxinus mandshurica community and Corn us controversa community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH(diameter at breast height) were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica(67.8), F. mandshurica(44.8), Q. serrata(27.5), Acer pseudo-sieboldianum(17.0), C. controversa(l5.9), F. sieboldiana(l1.5), R. schlippenbachii(11.0), C. cordata(11.0), Styrax obassia(10.9), Magnolia sieboldii(10.4) and C. laxiflora(9.8). Distribution of DBH of Q. mongolica had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. Q. serrata had a higher frequency of young individuals and middle individuals, suggesting a continuous domination of these species over the other species for the time being in contrast. This study examined the correlation between each community and the environment according to DCCA ordination. The Q. mongolica community predominated in the highest elevation habitats which had many C.E.C and T-N. F. mandshurica community predominated in the highest elevation habitats which had many Moisture and EX-Cation. The Q. serrata community and C. laxiflora community mainly occurred in the low elevation habitats which had few C.E.C and T-N. The C. controversa community appeared on the park in the middle habitats.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.105-117
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• 2018

This study conducted health assessment and multivariate vegetation analysis using the riparian vegetation index in 30 sites of the Geumgang mainstream and Mihocheon to obtain practical data on the river management of the Geumgang. The result showed that the number of plant communities was 54. The flora was 75 families, 185 genera, 243 species, 2 subspecies, 21 varieties, 2 varieties, and 268 taxa. The riparian vegetation index was 38.3 (3.3; G-D1 ~ 66.7; G-U2, G-U4, and G-M3), and the health of the rivers in this area was evaluated as normal (grade C). The health of rivers was the highest in the upper stream of Geumgang mainstream and lowest in the downstream of Geumgang mainstream. The relationship between riparian vegetation index and chlorophyll-a content was low. The riparian vegetation was divided into five groups of Digitaria ciliaris colony group, Salix gracilistyla colony group, Erigeron annuus colony group, the group dominated by Humulus japonicus, Salix koreensis, Miscanthus sacchariflorus, and Phragmites japonica colonies, and the group dominated by Conyza canadensis and Echinochloa crusgalli var. echinata colonies. They had the similar health conditions. The CCA analysis showed that the environmental factors affecting the distribution of vegetation were physical factors such as vegetation area, artificial structure area, waterway area, branch width, channel width, and bank height and the biological factors such as the number of species. As such, it is necessary to maintain the health condition through continuous monitoring where the health condition is high and to apply active measures such as ecological restoration where the health condition is low.

• Food Science and Preservation
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• v.8 no.3
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• pp.239-245
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• 2001

The CA(Controlled Atmosphere) storage of cherry tomatoes were carried out under seven gas compositions including air. The weight loss of cherry tomatoes progressively increased with storage time. In the case of cherry tomatoes stored under CA conditions, increment of weight loss was reduced. However, cherry tomatoes (in air) tut about 15% weight at the end of storage. In CA stored cherry tomatoes lost about 10% weight at the same time. General trend was a decrease in titratable acidity with storage time. In air md 6.4% O$_2$, 4.2% CO$_2$, titratable acidity was lower than that in other storage conditions. During storage of cherry tomatoes, soluble solids increased till 8 days of storage, and then decreased. Stored cherry tomatoes in air and 6.4% O$_2$+4.2% CO$_2$ have lower values. Lycopene contents of cherry tomatoes with 6% O$_2$ storage condition increased and cherry tomatoes with 1% O$_2$+6% CO$_2$ and 3% O$_2$+3.1% CO$_2$maintained s initial contents. In air, flesh firmness decrease till 8 days, and then increase. At 1% O$_2$+6% CO$_2$ ethanol contents were ten times to that of other experimental conditions. Air and 6% O$_2$+7.8% CO$_2$ condition had lowest value for the ethanol content. In changes of organic acid and citric acid decreased slowly during storage, malic acid in air and below 3% O$_2$was disappeared at 8 days. Above 4% O$_2$concentration malic acid contents were maintained till 16 days. In over all acceptability, air and 6.4% O$_2$+7.8% CO$_2$ condition took a good score from the panel. Quality of stored cherry tomatoes was not edible condition in 1% O$_2$+6% CO$_2$. CA storage cherry tomatoes took a good score in firmness and juiciness where as control received good score in color and sweetness. This result was explained that in air ad 6.4% O$_2$+7.8% CO$_2$stored cherry tomato was ripened and full color development, but in CA was break stage because of suppressed ripening.