• Journal of Environmental Science International
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• v.17 no.10
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• pp.1139-1146
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• 2008

To investigate the functional properties and the antioxidant effect of pine needle(Pinus densiflora), the pine needle extract was obtained with methanol and its functionality was measured by spectrophotometric method, and the antioxidant experiment on soybean oil was carried out by the active oxygen method. The extraction yield of pine needle with 99% methanol was about 19%, the total flavonoid content of the pine needle-methanol extract was 11.32 mg/g on dry basis and the superoxide dismutase-like activity was 94.3%. The nitrite scavenging ability of the extract was pH dependent with the values of 77.44% at pH 1.2, 48.45% at pH 3.0 and 11.04% at pH 6.0, respectively. The peroxide value was 92.6 meq/kg at 5% dosage, 138.4 meq/kg at 2% dosage of the extract on 8 oxidation days. The period of the peroxide value to be 100 mg/kg was 4.9, 6.3 and 8.5 days at control, 2% and 5% dosage of extract, respectively. And the relative antioxidant effectiveness of the extract was 27.9% and 72.3% increase at 2% and 5% dosage, respectively, compared to control. The thiobarbituric acid value showed few differences within 4 oxidation days, but with the dosage of the extract it fairly decreased with considerable antioxidant effect to control above 4 days.

• Computers and Concrete
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• v.20 no.2
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• pp.145-154
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• 2017

In geological engineering, grouting with Portland cement is a common technique for ground improvement, during which micro-fine cement is applied as a slurry, such that it intrudes into soil voids and decreases soil porosity. To determine the utility and behavior of cements with different Blaine values (index of cement particle fineness) for stabilization of fine sand, non-destructive and destructive tests were employed, such as laser-ray determination of grain size distribution, and sedimentation, permeability, and compressive strength tests. The results of the experimental study demonstrated a suitable mix design for the upper and lower regions of the cement-grading curve that are important for grouting and stabilization. Increasing the fineness of the cement decreased the permeability and increased the compressive strength of grouted sand samples considerably after two weeks. Moreover, relative to finer (higher Blaine value) or coarser (lower Blaine value) cements, cement with a Blaine value of $5,100cm^2/g$ was optimal for void reduction in a grouted soil mass. Overall, study results indicate that cement with an optimum Blaine value can be used to satisfy the designed geotechnical criteria.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.121-128
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• 2007

This paper suggests a way of estimating the value of interclass equity improvement by railway operations. Equity is understood in this paper in the context of a mobility gap between classes. The value of the reduced mobility gap by railway operations is interpreted as an increase of social equity. In particular, the unit value of equity improvement by rail services is quantified based on the amount of fare reduction through public service obligations. The difference in the surplus calculation between elastic and inelastic demands relative to the reduction is also discussed. The result of this study is expected to be helpful of performing more cautious appraisal for rail investment schemes.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.214-218
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• 1999

The aim of our study is to develop new algorism for sea fog detection by using Geostational Meteorological Satellite-5(GMS-5) and suggest the techniques of its continuous detection. So as to detect daytime sea fog/stratus(00UTC, May 10, 1999), visible accumulated histogram method and surface albedo method are used. The characteristic value during daytime showed A(min) > 20％ and DA < 10％ when visble accumulated histogram method was applied. And the sea fog region which detected is of similarity in composite image and surface albedo method. In case of nighttime sea fog(18UTC, May 10, 1999), infrared accumulated histogram method and maximum brightness temperature method are used, respectively. Maximum brightness temperature method(T_max method) detected sea fog better than IR accumulated histogram method. In case of T_max method, when infrared value is larger than T_max, fog is detected, where T_max is an unique value, maximum infrared value in each pixel during one month. Then T_max is beneath 700hpa temperature of GDAPS(Global Data Assimilation and Prediction System). Sea fog region which detected by T_max method was similar to the result of National Oceanic and Atmosheric Administration/Advanced Very High Resolution Radiometer (NOAA/AVHRR) DCD(Dual Channel Difference). But inland visibility and relative humidity didn't always agreed well.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.377-381
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• 2011

The purpose of this study is an assessment between the measured value of the nanoDot dosimeter and the calculated value of Non Dosimeter Dosimetry-Method(NDD-M) for entrance surface dose in general radiography. Measurement and calculation of the entrance surface doses were performed for head(AP), abdomen(AP), pelvis(AP), thoracic spine(AP) and lumbar spine(AP). As a result, the relative ratios of the measured value to the calculated value were acquired 1.5-2.1 for each region. Reproducibility acquired 0.035 as a coefficient of variation.

• Journal of Family Resource Management and Policy Review
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• v.2 no.1
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• pp.15-31
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• 1998

The purpose of study is to understand the home management strategy to cope with rapid changing environments and to verify that how personal value orientation affect home management strategy. The research results are summarized below. First, variables that affect the value orientation of Korean urbanite are sex, area of dwelling, degree of information using and degree of stress recognition in case of material orientation, degree of information using in case of environmental orientation, academic career, sex, degree of information using, degree of stress recognition in cases of fate control orientation, number of children, sex, degree of information using in case of equilibrium orientation, sex, degree of stress recognition in case of present orientation and academic career, degree of stress recognition in case of individualistic orientation. Second, value orientation variables that affect overall home management strategy of Korean urbanite are material orientation, environmental orientation, fate control orientation and individualistic orientation. Third, variables that affect overall home management strategy of Korean urbanite are age, academic career, degree of information using, degree of stress recognition, perception level of living relative to others, environmental orientation and fate control orientation and it is shown that degree of information using is domineering variable.

• Journal of Family Resource Management and Policy Review
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• v.2 no.2
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• pp.1-19
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• 1998

The purpose of study is to understand the home management strategy to cope with rapid changing environments and to verify that how personal value orientation affect home management strategy. The research results are summarized below. First, variables that affect the value orientation of Korean urbanite are sex, area of dwelling, degree of information using and degree of stress recognition in case of material orientation, degree of information using in case of environmental orientation, academic career, sex, degree of information using, degree of stress recognition in cases of fate control orientation, number of children, sex, degree of information using in case of equilibrium orientation, sex, degree of stress recognition in case of present orientation and academic career, degree of stress recognition in case of individualistic orientation. Second, value orientation variables that affect overall home management strategy of Korean urbanite are material orientation, environmental orientation, fate control orientation and individualistic orientation. Third, variables that affect overall home management strategy of Korean urbanite are age, academic career, degree of information using, degree of stress recognition, perception level of living relative to others, environmental orientation and fate control orientation and it is shown that degree of information using is domineering variable.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.301-304
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• 2012

Epoxy/microsilica (65 phr)/nanosilica (0~5 phr) composites (EMNC) were prepared in order to develop a high-voltage insulation material, where phr means parts per hundred relative to the epoxy oligomer. Tensile and flexural tests of the composites were carried out, and the AC electrical breakdown strength was measured, after which all the data were estimated by Weibull statistical analysis. As the nanosilica content increased, the tensile strength increased, and the highest value was 117.7 MPa in the EMNC system with 3 phr nanosilica, which was ca. 10% higher than that of the system without nanosilica. The value then decreased after 3 phr. The flexural strength and AC electrical breakdown strength showed the same tendencies as the tensile strength. The highest value of the flexural strength was 184.6 MPa in the EMNC system with 3 phr of nanosilica, which was ca. 15% higher than that of the system without nanosilica. The strongest value of the AC electrical breakdown strength was 79.0 kV/0.5 mm in the EMNC system with 3 phr of nanosilica, which was ca. 34% higher than that of the system without nanosilica.

• Journal of the Korean Ceramic Society
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• v.28 no.5
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• pp.399-405
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• 1991

Mullite-PSZ powders were synthesized by the sol-gel process using Al(sec-OC4H9)3, Si(OC2H5)4, ZrOCl2$.$8H2O and YCl3 solution and the characteristics of synthesized powders were studied. The sinterability and mechanical properties of powder compacts sintered at 1670$^{\circ}C$ for 4hr were also studied for various PSZ contents. ${\gamma}$-Al2O3(Al-Si spinel) formed at 980$^{\circ}C$ from amorphous dried gel, and mullite as well as ZrO2 formed above 1200$^{\circ}C$. At the room temperature, ZrO2 was a mixture of tetragonal and monoclinic phases. The specimens were densified to 97∼98% except the specimen containing 25 vol% PSZ which showed the relative density of 94%. The K1c value increased with the PSZ content and showed a maximum value of 4.1 MN/m3/2 at 25 vol% PSZ; this value was about 50% higher than that of the mullite without PSZ. Flexural strength had a maximum value of 280 Mn/㎡ at 20 vol% PSZ. In contrast, at 25 vol%, the flexural strength was even lower than that of the mullite possibly due to higher porosity of 6%.

• Journal of Environmental Science International
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• v.10 no.1
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• pp.21-25
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• 2001

The Keum river has been utilized for drinking water supply of several city including Kunsan city and is deepening pollution state due to numerous municipal and industrial discharges. The concentration BOD in river is affected by the organic loading from a tributary and the algae biomass that largely happen to under eutrophication state. In the eutrophic water mass such as the Keum river, the autochthonous BOD was very important part for making a decision of water quality management, because it was accounted for majority of the total BOD. The predict of water quality has important meaning for management of water quality pollution of the Keum river. The purpose of this study will manage and predict water quality of the Keum river using QUAL-2E model considering the autochthonous BOD. The estimation of autochthonous BOD represented that the relationship between BOD and chlorophyll a. The regression equation was shown to be autochthonous BOD=$\beta$(sub)5$\times$chlorophyll a. The results of this study may be summarized as followed; The QUAL-2E model was calibrated with the data surveyed in the field of the study area in June, 1998. The calculated value by QUAL-2E model are in good agree to measured value within relative error of 7.80~20.33%. Especially, in the case of the considering autochthonous BOD, the calculated value of BOD were fairly good coincided with the observed values within relative error of 15%. But the case of not considering autochthonous BOD, relative error of BOD was shown to be 43.2%. In order to attain II grade of water quality standard in Puyo station which has a intake facility of water supply, we reduced to the pollutants loading of tributaries. In the case of removed 100% BOD of tributaries, the BOD of Puyo station was 4.07mg/$\ell$, belong to III grade of water quality standard. But in the case of removed 88% nutrient of tributaries, it was satisfied to II grade of water quality standard as below 3mg/$\ell$ of BOD. For estimation of autochthonous BOD in Keum river, we are performed simulating in accordance with reduction of nutrient load(50~100%) under conditions removal 90% organic load. Occupancy of autochthonous BOD according to nutrient loading reductions were varied from 25.97~79.51%. Occupancy of autochthonous BOD was shown to be a tendency to increasing in accordance with reduction of nutrient loading. Showing the above results, the nutrient that one of the growing factor of algae was important role in decision of BOD in the Keum river. For the water quality management of the Keum river, therefore, it is necessary to considering autochthonous BOD and to construction of advanced sewage treatment plant for nutrient removal.