• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.1
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• pp.137-151
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• 2017

The space between urban buildings becomes a waterway during rain events and requires a boundary condition in numerical calculations on grids to separate overland storm flows from building areas. Minimization of the building data distortion as a boundary condition is a necessary step for generating accurate calculation results. A building generalization is used to reduce the distortion of building shapes and areas during a raster conversion. The objective of this study was to provide the appropriate threshold value for building generalization and grid size in a numerical calculation. The impact of building generation on the connectivity of urban storm waterways were analyzed for a general residential area. The building generalization threshold value and the grid size for numerical analysis were selected as the independent variables for analysis, and the number and area of sinks were used as the dependent variables. The values for the building generalization threshold and grid size were taken as the optimal values to maximize the building area and minimize the sink area. With a 3 m generalization threshold, sets of $5{\times}5m$ to $10{\times}10m$ caused 5% less building area and 94.4% more sink area compared to the original values. Two sites representing general residential area types 2 and 3 were used to verify building generalization thresholds for improving the connectivity of storm waterways. It is clear that the recommended values are effective for reducing the distortion in both building and sink areas.

• Journal of the Korean earth science society
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• v.29 no.7
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• pp.579-585
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• 2008

The time-dependent evolution of disk mass for outburst limit cycle in a black hole microquasar is calculated based on the non-linear hydrodynamic model of thermally unstable accretion disk. The physical parameters such as black hole mass, disk size and mass transfer rate are adopted to reproduce the historical 1975 outburst observed in a prototype black hole X-ray nova A0620-00. The time-dependent effect of irradiation from the central hot region to the disk is considered in two ways: direct irradiation and indirect irradiation reflected from hot accretion flow above the disk. The accretion disk thermal instability model can account for the bolometric luminosity appropriate to typical characteristics of system luminosity observed in X-ray transients during the whole cycle of the outburst evolution. The maximum mass of the accretion disk, ${\sim}4.03{\times}10^{24}g$, is achieved at the ignition of an outburst, and the minimum value, ${\sim}8.54{\times}10^{23}g$, is reached during the cooling decay to quiescence. The disk mass varies ${\sim}5$ times during outburst limit cycle.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.150-156
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• 2009

The removal of tiny particles adhered to surfaces is one of the crucial prerequisite for a further increase in IC fabrication, large area displays and for the process in nanotechnology. Various cleaning techniques (wet chemical cleaning, scrubbing, pressurized jets and ultrasonic processes) currently used to clean critical surfaces are limited to removal of micrometer-sized particles. Therefore the removal of sub-micron sized particles from silicon wafers is of great interest. For this purpose various cleaning methods are currently under investigation. In this paper, we report on experiments on the cleaning effect of 100nm sized fluorescence particles on silicon wafer using the plasma shockwave occurred by femtosecond laser. The plasma shockwave is main effect of femtosecond laser cleaning to remove particles. The removal efficiency was dependent on the gap distance between laser focus and surface but in some case surface was damaged by excessive laser intensity. These experiments demonstrate the feasibility of femtosecond laser cleaning using 100nm size fluorescence particles on wafer.

• Journal of Nutrition and Health
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• v.35 no.9
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• pp.903-911
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• 2002

The effects of dietary levan, high-molecular-weight $\beta$-2,6-linked fructose polymer, on adiposity, serum leptin and UCP expression in rats fed high fat diet were studied. The adipose tissue hormone, leptin has been proposed to be involved in the regulation of food intake and energy expenditure. Uncoupling protein (UCP), a mitochondrial protein that uncouples the respiratory chain from oxidative phosphorylation, generates heat instead of ATP, thereby increase energy expenditure. To determine whether the dietary levan may have the anti-obesity effect, 4 wk old Sprague Dawley male rats fed high fat diet for 6 wks to induce obesity, and subsequently fed one of three diets for further 6 wks: 1) high fat (40% of calories) diet without levan 2) with 3% (w/w) levan 3) with 5% levan. For the comparison, control group fed AIN-76A diet. Visceral and peritoneal fat masses were lower in high fat diet with levan groups compared to high fat diet group. The effect of levan was dose-dependent. Adipocyte size was significantly reduced in the levan diet groups compared to the no levan diet group. Serum cholesterol level was not affected by levan containing diet, while the serum HDL cholesterol level was higher in leven diet groups. In addition, serum triglyceride level was markedly reduced by levan containing diet, thus lower than that of control group. Serum leptin was reduced by levan containing diet and lower in 5% levan group compared to 3% levan group (p < 0.001), as a result, serum leptin and insulin levels of 5% levan group were reduced to level of control group. Futhermore, the serum leptin level reflected the adiposity. The expression of UCP 1, and UCP 2 in brown adipose tissue was up-regulated by levan containing diet. In conclusions, levan containing diet reduced adiposity and serum triglyceride but increased UCP expression in the obese rats fed high fat diet. (Korean J Nutrition 35(9) : 903~911, 2002)

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1830-1840
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• 2019

Loliolide is one of the most ubiquitous monoterpenoid compounds found in algae, and its potential therapeutic effect on various dermatological conditions via agent-induced biological functions, including anti-oxidative and anti-apoptotic properties, was demonstrated. Here, we investigated the effects of loliolide on hair growth in dermal papilla (DP) cells, the main components regulating hair growth and loss conditions. For this purpose, we used a three-dimensional (3D) DP spheroid model that mimics the in vivo hair follicle system. Biochemical assays showed that low doses of loliolide increased the viability and size of 3D DP spheroids in a dose-dependent manner. This result correlated with increases in expression levels of hair growth-related autocrine factors including VEGF, IGF-1, and KGF. Immunoblotting and luciferase-reporter assays further revealed that loliolide induced AKT phosphorylation, and this effect led to stabilization of β-catenin, which plays a crucial role in the hair-inductive properties of DP cells. Further experiments showed that loliolide increased the expression levels of the DP signature genes, ALP, BMP2, VCAN, and HEY1. Furthermore, conditioned media from loliolide-treated DP spheroids significantly enhanced proliferation and the expression of hair growth regulatory genes in keratinocytes. These results suggested that loliolide could function in the hair growth inductivity of DP cells via the AKT/β-catenin signaling pathway.

• Korean Journal of Materials Research
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• v.20 no.9
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• pp.494-499
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• 2010

Tin oxide thin films were prepared on borosilicate glass by rf reactive sputtering at different deposition powers, process pressures and substrate temperatures. The ratio of oxygen/argon gas flow was fixed as 10 sccm / 60 sccm in this study. The structural, electrical and optical properties were examined by the design of experiment to evaluate the optimized processing conditions. The Taguchi method was used in this study. The films were characterized by X-ray diffraction, UV-Vis spectrometer, Hall effect measurements and atomic force microscope. Tin oxide thin films exhibited three types of crystal structures, namely, amorphous, SnO and $SnO_2$. In the case of amorphous thin films the optical band gap was widely spread from 2.30 to 3.36 eV and showed n-type conductivity. While the SnO thin films had an optical band gap of 2.24-2.49 eV and revealed p-type conductivity, the $SnO_2$ thin films showed an optical band gap of 3.33-3.63 eV and n-type conductivity. Among the three process parameters, the plasma power had the most impact on changing the structural, electrical and optical properties of the tin oxide thin films. It was also found that the grain size of the tin oxide thin films was dependent on the substrate temperature. However, the substrate temperature has very little effect on electrical and optical properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.98-103
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• 2013

The alumina substrates that Ni electrode was printed on and the multi-layered PTCR thermistors of which composition is $(Ba_{0.998}Ce_{0.002})TiO_3+0.001MnCO_3+0.05BN$ were fabricated by a thick film process, and the effect of re-oxidation temperature on their resistivities and resistance jumps were investigated, respectively. Ni electroded alumina substrate and the multi-layered PTC thermistor were sintered at $1150^{\circ}C$ for 2 h under $PO_2=10^{-6}$ Pa and then re-oxidized at $600{\sim}850^{\circ}C$ for 20 min. With increasing the re-oxidation temperature, the room temperature resistivity increased and the resistance jump ($LogR_{290}/R_{25}$) decreased, which seems to be related to the oxidation of Ni electrode. The small sized chip PTC thermistor such as 2012 and 3216 exhibits a nonlinear and rectifying behavior in I-V curve but the large sized chip PTC thermistor such as 4532 and 6532 shows a linear and ohmic behavior. Also, the small sized chip PTC thermistor such as 2012 and 3216 is more dependent on the re-oxidation temperature and easy to be oxidized in comparison with the large sized chip PTC thermistor such as 4532 and 6532. So, the re-oxidation conditions of chip PTC thermistor may be determined by considering the chip size.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.327-334
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• 2005

This study was designed to investigate the effect of the surgical delay in the prefabricated cutaneous flap. Abdominal skin flaps (n=40), $4.5{\times}6.0cm$ in size, were created by the subcutaneous implantation of a saphenous vascular tissue in the male Sprague-Dawley rats. In the groups 1 and 2, the pedicle was skeletonized. In the groups 3 and 4, perivascular muscle cuff or gracilis fascia was retained, respectively. Six weeks later, each flap was elevated as an island flap and reposed in place. All flaps of the group 2 had a 72-hours of delay period. Five days after the flap repositioning, estimation of flap viability, microangiographies, and histological evaluation of vessel development were performed. The groups 2 and 3 showed higher viability in flap survival. The dilated choke vessels and fully developed vascular network were observed in the flap of the group 2, but not typically seen in the other groups. New vessels around the implanted pedicle were more developed in the group 2. Amount of the vessels in the mid-portion of the flap was significantly increased in the groups 2 and 4. In conclusion, the delay procedure enhanced the viability, and its effect was dependent on the new vessel formation around the implanted pedicle.

• Journal of the Korean housing association
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• v.26 no.5
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• pp.27-35
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• 2015

This study aims to analyze the housing satisfaction of 55 years and older (55+) single-person householders in U.S. urban communities with the 2011 American Housing Survey Data. Single-person householders younger than 55 years of age (55-) were used as a reference group. Housing Adjustment Theory was used to develop a research framework to depict the relationships of housing satisfaction (dependent variable) with demographic and housing variables (independent variables). The regression analysis revealed that age, health status, government income, race, gender, age of house, housing quality, neighborhood, structure type, and tenure status had a significant effect on housing satisfaction levels of both those aged 55- and 55+. However, for the cohort of 55+, education, census region, housing affordability, and structure size also affected their housing satisfaction. Neighborhood satisfaction had the strongest effect on housing satisfaction of both groups. These variables were discussed in terms of resources and constraints contributing to their housing satisfaction. This study highlights the present and future housing trends and challenges of U.S. single householders in U.S. urban communities.

• Journal of Preventive Medicine and Public Health
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• v.46 no.1
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• pp.28-38
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• 2013

Objectives: This study aimed to collect information that will help enhance the social networks and improve the quality of life among elderly people by observing the relationship between their social network and health-related quality of life (HRQoL) and by analyzing social network factors affecting HRQoL. Methods: This study was based on the 2008 Community Health Survey in Yeoncheon County. Three hundred elders were included in the study population. We compared the revised Lubben Social Network Scale (LSNS-R) score and Euro quality of life-5 dimensions health status index by demographic characteristics and chronic disease prevalence. We analyzed the data using multiple regression and tobit regression by setting the HRQoL as the dependent variable and social network and other characteristics as the independent variables. We analyzed social network factors by using factor analysis. Results: The LSNS-R score differed significantly according to age and existence of a spouse. According to the results from the hierarchical multiple regression analysis, the LSNS-R explained 0.10 of the variance and LSNS-R friends factor explained 0.10 of the variance. The tobit regression indicated that the contribution of the LSNS-R family size factor to the regression coefficient of the independent variable that affected the HRQoL was $B_T$=2.96, that of the LSNS-R family frequency factor was $B_T$=3.60, and that of LSNS-R friends factor was $B_T$=5.41. Conclusions: Social networks among elderly people had a significant effect on HRQoL and their networks of friends had a relatively higher effect than those of family members.