• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.107.2-107.2
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• 2012

We used the electrophoretic deposition (EPD) process to fabricate a glass composite and investigated the EPD parameters to find the optimum deposition time by understanding the relationship among the process parameters of zeta potential (ZP), pH, deposition yield and saturation point. A binder and a dispersing agent were mixed properly with glass frit ($0.2{\sim}25{\mu}m$, d50=$8.77{\mu}m$) in an ethyl alcohol medium for the preparation of the slurry. The pH and ZP were in an inverse relationship to each other due to the generation of $H_3O^+$ ions with the addition of the dispersing agent in the slurry. The acidic nature of the dispersing agent was resulted in a decrease of the pH and an increase of the ZP. Otherwise, the pH increased with the addition of the glass frit in the slurry because $H_3O^+$ ions were absorbed on the glass frit. Therefore, the $OH^-$ ions correspondingly increased. The saturation point of EPD was strongly correlated with the variation of the pH in the slurry; this is caused by a chemical reaction between the ethyl alcohol and the ions that make up the glass frit. An adjustment of the pH variation and the saturation point in the slurry can be established with respect to the optimum deposition time in the slurry.

• Journal of the Korean GEO-environmental Society
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• v.14 no.5
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• pp.41-47
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• 2013

Well-graded and dense soils have good engineering properties. Unsaturated soil properties such as shear strength, compressibility and permeability are closely related to the soil-water characteristic curve of the soil. Therefore it is important to study the effects of the coefficient of uniformity and the porosity on the soil-water characteristic curve of the sandy soils, which are also related to the grain size distribution and the density of the soil, respectively. In this study soil-water characteristic curves (SWCCs) for six sandy soil specimens were investigated using Tempe pressure cells. The test data were best-fitted to Fredlund and Xing equation. The obtained fitting parameters and the characteristic points of SWCCs were discussed and correlated with the porosity and the coefficient of uniformity of the specimens. The results show that the smaller the porosity of the specimen becomes, the larger the value of the residual matric suction becomes, whereas the larger the coefficient of uniformity of the specimen becomes, the larger the value of the residual matric suction becomes. Regardless of the coefficient of uniformity, the smaller the porosity of the specimen, the flatter the max. slope of SWCC.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.71-82
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• 2008

Survivin is a member of the inhibitors of apoptosis (IAP) family that have been known to inhibit activated caspases in apoptosis. In contrast to most IAP family members, survivin mRNA is expressed during fetal development, is not found in normal adult tissues and is overexpressed again in the cancer. Though survivin expression has been documented in most human cancers, little is known about its expression in OSCC and its potential value as a predictor of cancer survival. The purpose of this study was to investigate survivin expression in OSCC and to evaluate its value as a prognostic marker. We evaluated survivin expressions in cancer lines and OSCC samples and investigated the relationships between survivin expressions and clini-co-pathological parameters including stage, differentiation, proliferation, lymph node metastasis, blood vessel density, and gelatinolytic activity. With immunohistochemistry, we analyzed survivin expression in 38 OSCCs. Patients' clinico-pathological parameters and their survival rate were analyzed to reveal their correlations with Survivin expressions. We cultured oral cancer cell lines and evaluated the correlation between gelatinolytic activities and survivin expressions of them. Survivin protein was observed both in nuclei and cytoplasm of tumor specimens while little or not observed in normal gingival mucosal tissues. Additionally, survivin expressions were correlated with lymph node metastasis, tumor proliferation and survival rate. Survivin expression was observed in 100% of 38 samples of OSCC and its expression levels are statistically associated with the proliferative activity of the tumors, lymph node metastasis and the survival of the patients. Based on these results, survivin is commonly expressed in OSCC and may thus provide valuable prognostic information related with lymph node metastasis, proliferation and survival rate as well as a potential therapeutic target in OSCC.

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.217-224
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• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• The Korean Journal of Food And Nutrition
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• v.12 no.3
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• pp.279-289
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• 1999

This study was conducted to investigate the physical characteristics and risk factors for hyperchol-esterolemia (HC) in Korean. 344 adult men who took the annual health check-ups at D or J hospitals were participated in this cross-sectional study. The subjects were grouped by plasma total cholesterol level in to three groups: normal cholesterolemic (n=139) borderline hypercholesterolemic(n=93) and hypercholesterolemic (n=112) groups. The data of height weight and plasma cholesterol level were col-lected from medical records. Body circumferences(midarm, waist, hip, and thight) skinfold thicknesses (biceps, triceps, subcostal, abdomen, and suprailic), and body composition (fat mass and fat free mass) were measured. Body mass index (BMI) height/weight ratio (HWR) waist/hip circumference ratio (WHR) waist/ thigh circumference ratio (WTR) central skinfold thickenss (CSF) and peripheral skin-fold thickness were calculated. The subjects with HC had significantly higher weight BMI waist cir-cumference skinfold thickness and body fat mass than those of the normal subjects. The relative and attributable risks on HC were 1.61 and 0.17 for obesity (BMI$\geq$25) 1,30 and 0.11 for upper body obesity (WTR$\geq$1.30) and 1.54 and 0.18 for central body obesity (CSF$\geq$95.7). Plasma total cholesterol level was positively correlated with several antropometric parameters: BMI (p<0.001) weight(p<0.001) waist circumference(p<0.001) and skinfold thickness of abdomen (p<0.001) spraillic (p<0.01) triceps(p<0.01) subcostal (p<0.01) and biceps (p<0.05) In conclusion the major influencing factors to plasma cholesterol level was BMI. Among the each physical parameters the circumference of waist the skinfol-d thickness of abdomen and the percentage of body fat were closely related to plasma cholesterol level. The important risk factor for hypercholesterolemia was obesity specially upper body obesity and central body obesity.

• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.171-177
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• 2014

Purpose: Eosinophilia is common in premature infants, and its incidence increases with a shorter gestation period. We investigated the clinical significance of eosinophilia in premature infants born at <34 weeks gestation. Methods: We analyzed the medical records of premature infants born at <34 weeks gestation who were admitted to the neonatal intensive care unit at Ewha Womans University Mokdong Hospital between January 2003 and September 2010. Eosinophilia was defined as an eosinophil percentage of >3% of the total leukocytes. Perinatal parameters and clinical parameters were also analyzed. Results: Of the 261 infants born at <34 weeks gestation, 22.4% demonstrated eosinophilia at birth. The eosinophil percentage peaked in the fourth postnatal week at 7.5%. The incidence of severe eosinophilia increased after birth up to the fourth postnatal week when 8.8% of all patients had severe eosinophilia. Severity of eosinophilia was positively correlated with a lower gestational age, birth weight, and Apgar score. Respiratory distress syndrome, bronchopulmonary dysplasia, nephrocalcinosis, intraventricular hemorrhage, and sepsis were associated with a higher eosinophil percentage. The eosinophil percentage was significantly higher in infants with bronchopulmonary dysplasia from the first postnatal week and the percentage was the highest in the fourth postnatal week, with the maximal difference being 4.1% (P<0.001). Conclusion: Eosinophilia is common in premature infants and reaches peak incidence and severity in the fourth postnatal week. The eosinophil percentage was significantly higher in bronchopulmonary dysplasia patients from the first postnatal week. Severe eosinophilia was significantly associated with the incidence of bronchopulmonary dysplasia even after adjusting for other variables.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.55-65
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• 2014

Radar remote sensing is appropriate for rice monitoring because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. And we applied the relationships to crop monitoring of paddy rice in North Korea. As a result, plant height and Leaf Area Index (LAI) increased until Day Of Year (DOY) 234 and then decreased, while fresh weight and dry weight increased until DOY 253. Correlation coefficients revealed that Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients were correlated highly with plant height (r=0.95), fresh weight (r=0.92), vegetation water content (r=0.91), LAI (r=0.90), and dry weight (r=0.89). Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients. Concerning the evaluation for the applicability of the LAI distribution from RADARSAT-2, the LAI statistic was evaluated in comparison with LAI distribution from RapidEye image. And LAI distributions in Pyongyang were presented to show spatial variability for unaccessible areas.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.37.2-37.2
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• 2009

In this study, we present a new empirical forecasting method of solar proton events based on flare parameters. For this we used NOAA solar energetic particle (SEP) events from 1976 to 2006 and their associated X-ray flare data. As a result, we found that about only 3.5% (1.9% for M-class and 21.3% for X-class) of the flares are associated with the proton events. It is also found that this fraction strongly depends on longitude; for example, the fraction for $30W^{\circ}$ < L < $90W^{\circ}$ is about three times larger than that for $30^{\circ}E$ < L < $90^{\circ}E$. The occurrence probability of solar proton events for flares with long duration (> 0.3 hours) is about 2 (X-class flare) to 7 (M-class flare) times larger than that for flares with short duration (< 0.3 hours). The relationship between X-ray flare peak flux and proton peak flux as well as its correlation coefficient are strongly dependent on longitude. Using these results for prediction of proton flux, we divided the data into 6 subgroups depending on two parameters: (1) 3 longitude ranges (east, center, and west) and (2) flare impulsive times (long and short). For each subgroup, we make a linear regression between the X-ray flare peak flux and the corresponding proton peak flux. The result shows that the proton flux in the eastern region is much better correlated with the X-ray flux than that in the western region.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.1
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• pp.61-72
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• 2001

The effects of wave groups on reflection and transmission over a submerged breakwater are studied by using a hydrodynamic numerical model and five independent wave grouping parameters. Based on qualitative analyses of limited data, it is found that the reflection and transmission coefficients of submerged breakwater may be strongly correlated with the incident wave groups. The reflection and transmission coefficients tend to decrease as wave groups become relatively larger. In particular, the reflection and transmission coefficients due to wave groups are evaluated smaller than those of single incident waves. However, the reflection and transmission coefficients are not affected by the interval of higher wave groups. It is finally concluded that the mean of nul-length among wave grouping parameters can be an useful parameter for correlating the wave groups with the reflection and transmission coefficients of submerged breakwater.

• Journal of Electrochemical Science and Technology
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• v.1 no.1
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• pp.31-38
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• 2010

In this study, we have demonstrated the fine structure effect of PdCo electrocatalyst on oxygen reduction reaction activity with different alloy composition and heat-treatment time. In order to identify the intrinsic factors for the electrocatalytic activity, various X-ray analyses were used, including inductively coupled plasma-atomic emission spectrometer, transmission electron microscopy, X-ray diffractometer, and X-ray Absorption Spectroscopy technique. In particular, extended X-ray absorption fine structure was employed to extract the structural parameters required for understanding the atomic distribution and alloying extent, and to identify the corresponding simulated structures by using FEFF8 code and IFEFFIT software. The electrocatalytic activity of PdCo alloy nanoparticles for the oxygen reduction reaction was evaluated by using rotating disk electrode technique and correlated to the change in structural parameters. We have found that Pd-rich surface was formed on the Co core with increasing heating time over 5 hours. Such core shell structure of PdCo/C showed that a superior oxygen reduction reaction activity than pure Pd/C or alloy phase of PdCo/C electrocatalysts, because the adsorption energy of adsorbates was apparently reduced by lowering the dband center of the Pd skin due to a combination of the compressive strain effect and ligand effect.