• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.661-662
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• 2013

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.34-41
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• 2004

The purpose of this paper is to look at the characteristics of surface finishing which is one of the form accuracies and to obtain the fundamental technical data from the process of machining with diamond tool through experiment and theoretical analysis. The experiments were conducted with domestic made ultra-precision machine and MCD.PCD tool, with aluminum alloyed material and brass being used for the work pieces. The goal of the size accuracy was set to 100nm. The most suitable tool nose radius and machining conditions were selected, and the variations of the surface roughness were observed using SEM method while machining the distance of up to 500km. These data were evaluated and they examined the variation of the machined surfaces while cutting up to 500km of machining distance. At the same time, the state for the wear of diamond tool nose was analyzed and carefully examined through the newest measuring device. Additionally, the characteristics of ultra-precision machining technology were studied through visual analysis.

• Textile Coloration and Finishing
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• v.15 no.1
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• pp.39-47
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• 2003

Phosphorescent PET/liquid color films and phosphorescent PET/disperse dyes films were prepared by melt casting method using Hot press. Then, weight ratios and exhaustion percent of films were 0.7, 1.2, 1.5, 2.0, and 2.3 wt.%. The effects of L/C and D/D contents(wt.%) of films on the thermal properties, crystal structure, H(%), brightness$(mcd/mm^2)$, morphology, and tensile properties were investigated by means of DSC and WAXD, etc. It was found that the melting temperature and crystalline diffraction peaks were not changes with increasing the liquid color contents and disperse dyes exhaustion. Also, in case of using liquid color to phosphorescent PET film, the H(%) and brightness$(mcd/mm^2)$ value were superior to phos.PET/disperse dyes film. The tensile strength and the tensile modulus were decreased with increasing the contents of liquid color and exhaustion of disperse dyes in the phosphorescent PET film. Also, the elongation at break was increased with increasing the contents of liquid color and exhaustion of disperse dyes in the phosphorescent PET film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.945-949
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• 2005

We have grown GaN layers with in-situ SiN mask by metal organic chemical vapor deposition (MOCVD) and study the physical properties of the GaN layer. We have also fabricate PN junction light emitting diode (LED) to investigate the effect of the SiN mask on its optical property By inserting a SiN mask, (102) the full width at half maximum (FWHM) decreased from 480 arcsec to 409 arcsec and threading dislocation (TD) density decreased from $3.21{\times}10^9\;cm^{-2}$ to $9.7{\times}10^8\;cm^{-2}$. The output power of the LED with a SiN mask increased from 198 mcd to 392 mcd at 20 mA. We have thus shown that the SiN mask improved significantly the physical and optical properties of the GaN layer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.38-45
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• 1993

The feature based modeling approach is useful for post-CAD related works such as process planning and NC part programming. This paper describes the development of 'FeaTURN' system which is feature based NC part programming system for turning operation. The programming task in 'FeaTURN' system becomes easy and effective with the assistance of feature icons. The manufacturing attributes can be handled toghther with the features during input procedure. The cutter location data (CLD) is determined by the processor module. The post process module converts the CL data to machine control data (MCD). Also, the system graphically displays the tool path.

• Korean Journal of Remote Sensing
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• v.34 no.4
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• pp.601-610
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• 2018

The national accuracy of global land cover (GLC) products is of great importance to ecological and environmental research. However, GLC products that are derived from different satellite sensors, with differing spatial resolutions, classification methods, and classification schemes are certain to show some discrepancies. The goal of this study is to assess the accuracy of four commonly used GLC datasets in South Korea, GLC2000, GlobCover2009, MCD12Q1, and GlobeLand30. First, we compared the area of seven classes between four GLC datasets and a reference dataset. Then, we calculated the accuracy of the four GLC datasets based on an aggregated classification scheme containing seven classes, using overall, producer's and user's accuracies, and kappa coefficient. GlobeLand30 had the highest overall accuracy (77.59%). The overall accuracies of MCD12Q1, GLC2000, and GlobCover2009 were 75.51%, 68.38%, and 57.99%, respectively. These results indicate that GlobeLand30 is the most suitable dataset to support a variety of national scientific endeavors in South Korea.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.53-58
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• 1997

It is well known that the equiatomic FeAl alloy crystallizes in a paramagnetic CsCl structure and is very stable in a wide temperature range owing to a significant charge transfer from Al to Fe. A presence of structural defects normally enhances the magnetic and magneto-optical properties of this alloy. In this study spin-resolved photoemission and magnetic circular dichroism (MCD) were carried out on both ordered and disordered $Fe_{0.52}Al_{0.48}$ alloy films. The disordered state in the alloy films was obtained by a vapor quenching deposition on cooled substrates. It is shown that the order-disorder transition in the Fe0.52Al0.48 alloy films leads to a significant change in the spin polarization. Form the MCD results the orbital and spin magnetic moments of the constituent atoms are obtained. According to the sum rule the spin and orbital magnetic moments of Fe in the disordered FeAl film are $\mu\frac{SR}{spin}=0.8\mu_B$ and $\mu\frac{SR}{orb}=0.14\mu_B$ respectively. The spin magnetic moment is also evaluated to be $\mu\frac{BR}{spin}=0.77\mu_B$ by the branching ration method employing a photon polarization of 90%.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.1
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• pp.29-44
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• 1990

In 105 patients with the past history of poor response to the previous controlled ovarian hyperstimulation(COH) due to poor follicular growth or premature LH surge, the effectiveness of pituitary suppression with gonadotropin-releasing hormone agonist(GnRH agonist) in IVF/GIFT program was evaluated in 112 cycles of COH using a combination regimen of Leuprolide acetate (Lupron TAP Pharmaceuticals, USA) and FSH/hMG or pure FSH from May to December, 1989 at SNUH. Starting on day 21 of the menstrual cycle(MCD #21, Day 1), Lupron (1.0mg/day, subcutaneous) was administered once a day till next MCD #3(suppression phase). After the confirmation of pituitary suppression, ovarian follicular growth was stimulated with FSH/hMG or pure FSH from MCD #3(Day + 1), and Lupron was continued with hMG or FSH until hCG administration (D 0) (stimulation phase). After suppression phase, serum E2 level decreased from 183.7${\pm}$95.1(Day 1) to 17.4${\pm}$12.3pg/ml (Day +1), and serum progesterone level from 19.17${\pm}$8.67 to 0.12${\pm}$0.05ng/ml. But there was no decresas in serum LH and FSH levels; LH from 12.74${\pm}$6.21 to 15.49${\pm}$4.93mIU/ml,FSH from 7.60${\pm}$3.84 to 8.58${\pm}$3.15 rnlU/ml. There was no occurrence of premature LH surge during COH. Eleven cycles(9.8%) were cancelled due to poor follicular growth during stimulation phase, and 3 cycles (3.0%) failed in the transvaginal oocytes fretrieval. Serum E2 level was 1366.8${\pm}$642.4 on D 0 and 1492.3${\pm}$906.9pg/ml on D+1. 7.00${\pm}$3.32 follicles(FD${\geq}$12mm) were observed on D 0, and 6.11${\pm}$4.15 oocytes were retrieved, with the oocyte retrieval rate per follicle of 95.0%. 3.59${\pm}$2.57 oocytes were fertilized and cleaved with the oocyte cleavage rate of 55.7%. In 83 IVF patients, 4.08${\pm}$2.39 embryos were transferred, and 16 pregnancies were obtained with the pregnancy rate per ET 2.39 mebryos were transferred, and 16 pregnancies were obtained with the pregnancy rate per ET of 19.3%. In 6 GIFT patients, 7.83${\pm}$3.31 oocytes were retrieved and transferred with maximum number of 6, but no pregnancy was obtained. When compared with the previous 108 cycles of COH using FSH/hMG or pure FSH regimen, the cancellation rate during COH was significantly decreased, and all the parameters of the outcome of COH including the pregnancy rate were increased. These data suggest that GnRH agonist therapy for pituitary suppression is an effective adjunct to the current gonadotropin regimens for COH in IVF/GIFT and can increase the probability of oocytes retrieval and pregnancy, especially in the previous poor responders.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.980-985
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• 2010

The objective of this study was to isolate and identify anti-inflammatory chemicals in Hippophae rhamnoides L. which was grown in Chuncheon, Korea. Treatment of ethanol extracts from stems, leaves, roots, and fruits to RAW 264.7 cells reduced amounts of nitrite by 56.0, 31.9, 49.1, and 18.9% respectively, compared to only lipopolysaccharide (LPS) treatment which is well-known as a inflammation-inducing agent. The stems were extracted with hexane, dichloromethane, ethyl acetate, butanol, and water and their nitrite contents in RAW 264.7 cells were measured. The dichloromethane extracts showed the highest inflammatory activity, exhibiting 80% reduction of the nitrite content at 1 mg/mL treatment. Activity-directed fractionation of dichloromethane extracts led to the identification of $\beta$-sitosterol as the anti-inflammatory chemical. 0.1 mg/mL treatment of $\beta$-sitosterol inhibited strongly the production of nitrite by 65%, compared to only LPS treatment. These results suggest that stem of H. rhamnoides L. may be useful for inflammation treatment.

• Journal of Korea Water Resources Association
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• v.53 no.7
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• pp.545-555
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• 2020

A feasibility modeling for potential hydroelectric dam site selection was suggested using 1 sec ASTGTM (ASTER Global Digital Elevation Model) and Terra/Aqua MODIS (Moderate Resolution Imaging Spectroradiometer) derived land use (MCD12Q1) data. The modeling includes DEM pre-processing of peak, sink, and flat, river network generation, watershed delineation and segmentation, terrain analysis of stream cross section and reservoir storage, and estimation of submerged area for compensation. The modeling algorithms were developed using Python and as an open source GIS. When a user-defined stream point is selected, the model evaluates potential hydroelectric head, reservoir surface area and storage capacity curve, watershed time of concentration from DEM, and compensation area from land use data. The model was tested for 4 locations of already constructed Buhang, BohyunMountain, Sungdeok, and Yeongju dams. The modeling results obtained maximum possible heads of 37.0, 67.0, 73.0, 42.0 m, surface areas of 1.81, 2.4, 2.8, 8.8 ㎢, storages of 35.9, 68.0, 91.3, 168.3×10⁶ ㎥ respectively. BohyunMountain and Sungdeok show validity but in case of Buhang and Yeongju dams have maximum head errors. These errors came from the stream generation error due to ASTGTM. So, wrong dam watershed boundary limit the head. This study showed a possibility to estimate potential hydroelectric dam sites before field investigation especially for overseas project.