• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1343-1349
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• 2017

This study was carried out to determine the simultaneous extraction conditions of functional components (lutein, ${\beta}$-carotene, total polyphenol, flavonoids, and phenolic compounds) from sweet potato leaves and to evaluate the antioxidant activities. Extraction conditions included different ethanol concentrations (1st extraction: 99.9% ethanol; 2nd extraction: 50~90% ethanol) and times (30, 60, and 90 min). The highest values of lutein and ${\beta}$-carotene content were obtained by the 2nd extraction at an ethanol concentration of 90%. The extraction yields of lutein and ${\beta}$-carotene decreased with increasing extraction time. The maximum polyphenol, flavonoid, and total phenolic acid contents and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities were 32.3 mg gallic acid equivalent/g, 17.0 mg catechin equivalent/g, 2,842.6 mg/100 g, 17.0 mg ascorbic acid equivalent/g, and 1.94 mg/mL ($IC_{50}$) at the 2nd extraction with an ethanol concentration of 60%. The optimum extraction conditions were as follows; ethanol concentrations of the extraction solvent were 99.9% (1st extraction) and 60% (2nd extraction), and extraction time was 30 min.

• Journal of The Korean Dental Society of Anesthesiology
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• v.11 no.2
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• pp.141-145
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• 2011

배경: 협조가 불가능하거나 진정법 하 치과치료가 여의치 않을 경우 전신마취 하 치료를 계획하게 된다. 하지만 전신마취 하 치료시 기관내 삽관이 여의치 않은 경우를 종종 경험하게 된다. 이와같은 경우 기관지경을 이용한 기관내 삽관을 시행한다. 기관지 내시경을 환자의 성문에 근접하게 전진시킬 경우 기관지 내시경 하 시야확보가 용이한 점을 감안 시 비공 - 성대간 거리를 예측하는 것은 매우 유용할 것으로 생각된다. 또한 비공 - 성대간 거리를 추정하게 되면 맹목적 비강내 기관내 삽관을 하는데도 도움이 된다. 방법: 본 연구는 전신마취하 치과치료가 예정되어 있는 62명의 소아환자들을 대상으로 하여 신체변수와 비공 - 성대거리와의 관계를 확인해보고자 하였다. 선형회귀분석을 시행하여 다음과 같은 결론을 도출하였다. 결과: 소아환자들에 있어 비공 - 성대간 거리는 환아의 신장, 체중, 연령 등과 상관관계를 나타내었다. 비공 - 성대간 거리와 상관관계를 보인 변수들 중 에서 신장과의 상관계수가 가장 높았다. 선형회귀분석을 통해 비공 - 성대간 거리를 예측하는 다음과 같은 회귀식을 구하였다. 비공 - 성대간 거리 = (4.8 + 신장(cm)) ${\times}$ 0.07 고찰: 본 연구에서 구해진 회귀식을 이용하여 기도유지가 어려운 소아의 기도유지 하는데 큰 도움이 될 것으로 생각된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.150-155
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• 2018

In Korea, the mechanization ratio of field farming is about 58.3%. Especially, mechanization ratio of harvest operation is 10% or less. So, it is required to improve the mechanization ratio of harvest operation to analyze the power requirement analysis of agricultural tractor. The purpose of this study is to analyze power requirement of the underground crop harvester attached on agricultural tractor for traction operation. First, a power measurement system was developed and installed in 45 kW agricultural tractor. Second, field experiments were conducted at two driving speed levels (1.41, 2.17 km/h), and axle torque and rotation speed were analyzed. At 1.41km/h driving speed, the average power requirement of driving axle is 3.13 kW, respectively, at 2.17km/h driving speed, the average power requirement of driving axle is each 4.20 kW. In addition, the field tests show that as the driving speed increases by 53%, the power requirement of the underground crop harvester attached on agricultural tractor increases by 34%. Therefore, it indicated that the power requirement of agricultural tractor was affected by the driving speed.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.285-291
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• 2015

Exposure to cold sea water can be life-threatening to the drowned individual. Although appropriate life jacket can be usually be provided for the buoyance at the drowning accident, heat loss can make the drowned individual experience the hypothermia. Inflatable life jackets filled with inflatable air pocket can increase the thermal protection as well as the buoyancy force. Because it is important to know how the human body behaves unde the different life jacket, present study compares the thermal insulation capacity of solid type life jacket with that of inflatable life jacket. In order to represent the insulation capacity of life jacket, thermal resistance is estimated based on the assumption of steady-state. Also, a transient three-dimensional thermal distribution of the thigh is analyzed by using finite element method implementing the Pennes bioheat equation. The finite element model is a segmental, multi-layered representation of the body section which considers the heat conduction within tissue, bone, fat and local blood flow rate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.287-294
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• 2019

GGBFS(Ground Granulated Blast Furnace Slag) has been widely used in concrete for its excellent resistance chloride and chemical attack, however cracks due to hydration heat and dry shrinkage are reported. In many International Standards, GGBFS with low fineness of 3,000 grade is classified for wide commercialization and crack control. In this paper, the mechanical and durability performance of concrete were investigated through two mix proportions; One (BS) has 50% of w/b(water to binder) ratio and 60% replacement ratio with low-fineness GGBFS, and the other (TS) has 50% of w/b and 60% replacement ratio with 4000 grade and FA (Fly Ash). The strength difference between TS and BS concrete was not great from 3 day to 91 day of age, and BS showed excellent performance for chloride diffusion and carbonation resistance. Two mixtures also indicate a high durability index (more than 90.0) for freezing-thawing since they contain sufficient air content. Through improvement of strength in low fineness GGBFS concrete at early age, mass concrete with low hydration heat and high durability can be manufactured.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1656-1662
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• 2012

This study was conducted to evaluate the vegetative value of sweet potato leaves and stalks by investigating their chemical composition and antioxidant activity. The major minerals were found to be Ca and K. The crude protein content of the leaves ranged from 15.57% in Geonpungmi to 20.34% in Yeonhwangmi, while that of stalks was between 3.71% in Yulmi and 5.97% in Sinchunmi. The total phenolics and flavonoids content of the leaves were about 3.0~4.0 times higher than those of stalks. The levels of polyphenols and flavonoids were high in Geonpungmi leaf and in Sinchunmi stalk. ABTS radical activities were high in Geonpungmi leaf (58.75 mg AA eq/g) and in Daeyumi stalk (14.95 mg AA eq/g). DPPH radical scavenging was high in Geonpungmi and Jeungmi leaves ($IC_{50}$, 0.11 mg/mL) and in Sinchunmi stalk ($IC_{50}$, 1.09 mg/mL).

• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.193-203
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• 1999

In order to investigate systematically the steady shear flow properties of aqueous po1y(ethylene oxide) (PEO) solutions having various molecular weights and concentrations, the steady flow viscosity has been measured with a Rheometrics Fluids Spectrometer (RFS II) over a wide range of shear rates. The effects of shear rate, concentration, and molecular weight on the steady shear flow properties were reported in detail from the experimentally measured data, and then the results were interpreted using the concept of a material characteristic time. In addition, some flow models describing the non-Newtonian behavior (shear-thinning characteristics) of polymeric liquids were employed to make a quantitative evaluation of the steady flow behavior, and the applicability of these models was examined by calculating the various material parameters. Main results obtained from this study can be summarized as follows: (1) At low shear rates, aqueous PEO solutions show a Newtonian viscous behavior which is independent of shear rate. At shear rate region higher than a critical shear rate, however, they exhibit a shear-thinning behavior, demonstrating a decrease in steady flow viscosity with increasing shear rate. (2) As an increase in concentration and/or molecular weight, the zero-shear viscosity is increased while the Newtonian viscous region becomes narrower. Moreover, the critical shear rate at which the transition from the Newtonian to shear-thinning behavior occurs is decreased, and the shear-thinning nature becomes more remarkable. (3) Aqueous PEO solutions show a Newtonian viscous behavior at shear rate range lower than the inverse value of a characteristic time $1/{\lambda}_E$, while they exhibit a shear-thinning behavior at shear rate range higher than $1/{\lambda}_E$. For aqueous PEO solutions having a broad molecular weight distribution, the inverse value of a characteristic time is not quantitatively equivalent to the critical shear rate, but the power-law relationship holds between the two quantities. (4) The Cross, Carreau, and Carreau-Yasuda models are all applicable to describe the steady flow behavior of aqueous PEO solutions. Among these models, the Carreau-Yasuda model has the best validity.

• Journal of the Korean association of regional geographers
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• v.20 no.2
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• pp.206-216
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• 2014

In this study, forest types in Chungheongnam-do were analyzed using Landsat satellite images and digital forest type map as a means to estimate forest carbon stocks. NDVI and Tasseled Cap, ISODATA, and supervised classification among others were used to analyze the forest types. The forest carbon stocks of Chungcheongnam-do were estimated utilizing forest statistical data derived from the classified results. The results indicate that the analysis of forest types through supervised classification yielded the highest overall accuracy in analyzing forest types using satellite images. Coniferous forests(49.3%) accounted for the highest proportion in all the forest types of Chungcheongnam-do, followed by deciduous forests(28.0%) and mixed forests(22.7%). The results of a comparative analysis between forest carbon stocks estimates made using the modified digital forest type map and other estimation methods showed that the method using Tasseled Cap and unsupervised classification yielded the most similar forest carbon stock estimates. The most significant difference, though, was made when only the digital forest type map was used. It is expected that if carbon stocks are estimated by integrating satellite images and digital forest type maps in the future, more accurate results can be derived in estimating forest carbon stocks at a national level.

• The Journal of Engineering Geology
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• v.13 no.4
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• pp.457-474
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• 2003

This study aims to elucidate characteristics of groundwater level fluctuation at riverbank filtration sites in Daesan-myeon, Changwon City. Groundwater level fluctuation, river water level change and stream-aquifer interaction are very important to estimate optimal discharge rate of the pumping well. Water level contours from February 2003 to October 2003 show normal decreasing trend toward the Nakdong river with the hydraulic gradient of 0.008. However, flow reversion occurs when groundwater is discharged at the pumping wells or rise of the Nakdong river by rainfall. The fluctuation of the Nakdong river ranges 0 - 10 m msl. Autocorrelation analysis was conducted to the groundwater levels measured on the six monitoring wells (DS1, DS2, DS3, DS4, DS6 and DS7). The analyzed waterlevel data can be grouped into three: group 1 (DS1 and DS3) represents strong linearity and long memory effect, group 2 (DS1 and DS6) intermediate linearity and memory, and group 3 (DS4 and DS7) weak linearity and memory. Waterlevels of group 1 wells are relatively closely related to the change of river-water level. Those of group 2 wells are largely affected by the pumping and the river-water level, and those of group 3 wells are strongly linked to pumping.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.129-135
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• 2010

We described production of bioactive compounds from fungi grown on Korean ginseng-steaming effluents (GSE) for develop high-value added nutraceuticals from Korean GSE. Hansenula anomala KCCM 11473, which grew well in Korean GSE had high RNA content, and its optimal autolysis conditions were established to produce 5'-ribonucleotides (13.9~28.5 mg/g of biomass) at $55^{\circ}C$ and pH 5.0 for 24 h. 5'-Phosphodiesterase and adenyl deaminase were not effective in increasing the yield of 5'-ribinucleatides, but the yield of IMP increased significantly only after the addition of 1.0% adenyl deaminase. Saccharomyces cerevisiae showed the highest growth in the GSE medium. 267.1 mg of S. cerevisiae biomass was produced from 1 g of GSE solid and medicinal ginsenoside-$Rg_3$ contents was determined with 0.033 mg. Mucor miehei KCTC 6011 produced approximately 120 mg of chitosan per g-dry mycelium in 84 h at $25^{\circ}C$ when grown in the GSE (pH 8.0) supplemented with 0.5% yeast extract and 0.002% $CuSO_4$. Chitosan produced by M. miehei KCTC 6011 have deacetylated approximately 56% and its viscosity and molecular weight of the chitosan were 80 cps and $1.07\times10^3$ kDa, respectively. The chitosan at 1.5 mg/ml inhibited 73.9% of the mycelium growth of Rhizotonia solani in 60 h.