• 천문학회지
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• 제38권2호
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• pp.303-306
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• 2005

Transient luminous events (TLEs; sprites, elves, jets and etc.) are lightning-related optical flashes occurring above thunderstorms. Since the first discovery of sprites in 1989, scientists have learned a great deal about the morphological, spectroscopic and electromagnetic characteristics of TLEs through ground and spacecraft campaigns. However, most of the TLE studies were based on events recorded over US High Plains. To elucidate the possible biasing effects, space-borne observations are needed and have their merits. Imager of sprites and Upper Atmospheric Lightning (ISUAL) on the FORMOSAT-2 satellite is the first instrument to carry out a true global measurement of TLEs from a low- earth orbit. In this short paper, we apply a common astronomical data analysis technique, two-color diagram, on the ISUAL spectrophotometer (SP) data. By choosing appropriated bandpasses and converting the measured flux of TLEs into the unit of magnitude, two-color diagrams of TLEs can be constructed. We demonstrate that two-color diagrams, which were constructed from the narrow-band spectrophotometer data, can be used to classify different types of TLEs and trace their temporal evolution. The amount of reddening due to Earth's atmosphere can also be estimated from two-color diagrams assembled from the broad-band spectrophotometer data.

• 한국초지조사료학회지
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• 제34권4호
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• pp.277-282
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• 2014

Nutritive value analysis of feed is very important for the growth of livestock, and ensures the efficiency of feeds as well as economic status. However, general laboratory analyses require considerable time and high cost. Near-infrared reflectance spectroscopy (NIRS) is a spectroscopic technique used to analyze the nutritive values of seeds. It is very effective and less costly than the conventional method. The sample used in this study was a corn kernel and the partial least square regression method was used for evaluating nutrient composition, digestibility, and energy value based on the calibration equation. The evaluation methods employed were the coefficient of determination ($R^2$) and the root mean squared error of prediction (RMSEP). The results showed the moisture content ($R^2_{val}=0.97$, RMSEP=0.109), crude protein content ($R^2_{val}=0.94$, RMSEP=0.212), neutral detergent fiber content ($R^2_{val}=0.96$, RMSEP=0.763), acid detergent fiber content ($R^2_{val}=0.96$, RMSEP=0.142), gross energy ($R^2_{val}=0.82$, RMSEP=23.249), in vitro dry matter digestibility ($R^2_{val}=0.68$, RMSEP=1.69), and metabolizable energy (approximately $R^2_{val}$ >0.80). This study confirmed that the nutritive components of corn kernels can be predicted using near-infrared reflectance spectroscopy.

• Spatial Information Research
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• 제18권3호
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• pp.73-83
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• 2010

본 연구는 정지장면의 연속영상간 각 픽셀위치에서 일어나는 통계적 특성을 활용하여 영상을 분할하는 기법을 제안한다. 공간정보의 획득과 분석에서 디지털 영상 처리 기법의 활용은 아주 중요한 의미를 가진다. 특히 디지털 영상의 영역 구분을 위해 다양한 영상 분할(image segmentation) 기법들이 활용되고 있다. 본 연구에서는 선행 연구한 연속프레임 영상의 분광학적 특성 분석의 결과를 바탕으로 연속 프레임 간 Randomness를 활용한 이미지 분할 방법을 제안하였다. 우선 연속 프레임 간 각 화소에 통계학적인 분석 방법을 적용하여 각 화소의 평균과 표준편차 값을 구하고, 이를 통하여 대상 영상에서 가장 신뢰할 만한 화소들을 찾아 씨앗 점(seed point)을 결정하였다. 그리고 이 씨앗 점들을 시작으로 이웃 화소 간 T-test를 실시하였으며, 이를 기반으로 영역 성장(region growing)의 개념을 적용하여 영상을 분할 할 수 있는 기법을 연구하였다. 제안방식의 성능을 검증하기 위하여 실험을 통하여 기존의 방식과 비교분석을 수행하였다. 이러한 실험의 결과 영상분할에서 영상의 단일 프레임을 활용한 것보다 연속 프레임을 활용한 경우가 유리함을 확인 할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.42-42
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• 2008

Considerable attention has been focused on the applications of flexible liquid crystal (LC)-based displays because of their many potential advantages, such as portability, durability, light weight, thin packaging, flexibility, and low power consumption. To develop flexible LCDs that are capable of delivering high-quality moving images, like conventional glass-substrate LCDs, the LC device structure must have a stable alignment layer of LC molecules, concurrently support uniform cell gaps, and tightly bind two flexible substrates under external tension. However, stable LC molecular alignment has not been achieved because of the layerless LC alignment, and consequently high-quality images cannot be guaranteed. To solve these critical problems, we have proposed a PDMS pixel-wall based bonding method via the IB irradiation was developed for fasten the two substrates together strongly and maintain uniform cell gaps. The effect of the IB irradiation on PDMS with PI surface was also evaluated by side structure configuration and a result of x-ray photoelectron spectroscopic analysis of PDMS interlayer as a function of binder with substrates. large number of PDMS pixel-walls are tightly fastened to the surface of each flexible substrate and could maintain a constant cell gap between the LC molecules without using any other epoxy or polymer. To enhance the electro-optical performance of the LC device, we applied an alignment method that creates pretilt angle on the PI surface via ion beam irradiation. Using this approach, our flexible LCDs have a contrast ratio of 132:1 and a response time of about 15 ms, resulting in highly reliable electro-optical performance in the bent state, comparable to that of glass-substrate LCDs.

• Journal of Applied Biological Chemistry
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• 제52권4호
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• pp.221-225
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• 2009

Lithospermum erythrorhizon has been known well as one of traditional medicine for fever reduction, detoxication, and blood circulation improvement. This study was carried out to isolate biological active compounds from roots of Lithospermum erythrorhizon and to investigate their low density lipoprotein (LDL) antioxidant and anticancer activities. The hexane extract of Lithospermi Radix has been separated on silica gel chromatography and a naphthoquinone pigment compound 1 has been isolated. The structure of the compound 1 has been identified by spectroscopic technique, including MS and NMR, as acetylshikonin (1). Acetylshikonin showed significantly inhibitory activity on $Cu^{2+}$-induced human LDL oxidation with $IC_{50}$ value of $8.8\;{\mu}M$ and obvious anticancer effect by inhibiting farnesyl:protein transferase (FPTase) activity with $IC_{50}$ value of $23\;{\mu}M$, which suggested that acetylshikonin might be useful for the treatment of atherosclerosis and cancer.

• 한국응용과학기술학회지
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• 제16권2호
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• pp.155-161
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• 1999

Red pepper powder (Capsicum annum L.) is an important seasoning as a kimchi ingredient in korea and most korean consumer tend to eat the korean red pepper powder as the better than other oriental country such as China. Near infrared reflectance spectroscopy (NIRS) was applied for discrimination according to geographical origin (Korea, China) of red pepper powder. The objective of this study is to determine if NIR technique could be used to discriminate between the korean red pepper powder and non-korean red pepper powder according to seed content and maxing ratio in red pepper powder by using the new method. Rapid, precise and nondestructive analysis method for determination of the geographical origin of red pepper powder by near infrared spectroscopy and chemometrics were performed. It has been observed discriminant analysis with PLS is adequate to determinate the geographical origin of red pepper powder. It tend to difficult the discrimination of geographical origin according to increase the seed content of red pepper powder. The accuracy of discrimination in mixed red pepper powder was range from 95.2% to 100%.

• 한국식품저장유통학회지
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• 제18권2호
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• pp.156-164
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• 2011

This study was conducted to develop a portable quality evaluation system of bee-honey by near infrared spectroscopic technique. Two kinds of bee-honeys from acacia and polyflower sources were tested in this study. The system consists of power supply, tungsten-halogen lamp, detector, and optical fiber probe. Performance of the system was analyzed by comparing the prediction accuracy of the laboratory spectrophotometer. Total of 346 spectra was divided into a calibration set and a prediction set. The PLS (Partial Least Squares) models were developed to predict the quality parameters of bee-honeys. Reflectance spectra, moisture contents, ash, invert sugar, sucrose, F/G ratio, HMF(hydroxy methyl furfural), and $C^{12}/C^{13}$ ratio of honeys were measured. The PLS models of the laboratory spectrophotometer showed good relationships between predicted and measured quality parameters of honeys in the wavelength range of 1.100~2.200 nm. The PLS analysis of the portable quality evaluation system showed good relationships between predicted and measured quality parameters of honeys in the wavelength range of 1.100~1.300 nm and 1.400~1.700 nm. The results showed the feasibility of the portable quality evaluation system to determine the quality parameters of bee-honey in the field during harvesting.

• 한국광물학회지
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• 제20권3호
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• pp.175-180
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• 2007

천연, 합성 그리고 전자빔 조사 처리된 다이아몬드간의 분광학적 특성을 연구하기 위해 FTIR 실험을 수행하였다. 실험에 사용된 모든 다이아몬드 시료에서 다이아몬드 고유 흡수 피크와 다이아몬드 내 질소와 관련된 흡수피크가 잘 나타났다. 합성 다이아몬드는 고온고압과 관련된 $1344 cm^{-1}$와 $1128 cm^{-1}$ 흡수피크를 보여주며 합성 다이아몬드에서만 나타나는 $1050 cm^{-1}$ 흡수피크를 보여 천연 다이아몬드와 잘 구분이 된다. 전자빔 조사에 의한 청색 다이아몬드와 붕소함량에 의한 청색 다이아몬드는 Type (천연 : Type IIb, 전자빔 처리 : Type Ia)으로 구별이 된다. 그러나 방사선 조사된 다이아몬드에서 일반적으로 나타나는 $1450 cm^{-1}$ 흡수피크가 미약한 것은 방사선의 종류, 조사량과 어넬링 과정과 관련이 있는 것으로 사료된다.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.464-470
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• 2013

PURPOSE. The aim of this Fourier transform infrared (FTIR) spectroscopic study was to measure the degree of conversion (DC) of dual-cured resin cements light-irradiated through zirconia ceramic disks with different thicknesses using various light-curing methods. MATERIALS AND METHODS. Zirconia ceramic disks (KT12) with three different thicknesses (1.0, 2.0, and 4.0 mm) were prepared. The light transmittance of the disks was measured using ultraviolet visible near-infrared spectroscopy. Four different light-curing protocols were used by combining two curing light modes (Elipar TriLight (standard mode) and bluephase G2 (high power mode)) with light-exposure times of 40 and 120 seconds. The DCs of the two dual-cured resin cements (Duo-Link and Panavia F2.0) light-irradiated through the disks was analyzed at three time intervals (3, 7, and 10 minutes) by FTIR spectroscopy. The data was analyzed using repeated measures ANOVA (${\alpha}$=.05).Two-way ANOVA and Tukey post hoc test were used to analyze the 10 minute DC results. RESULTS. The 1.0 mm thick disk exhibited low light transmittance (<25%), and the transmittance decreased considerably with increasing disk thickness. All groups exhibited significantly higher 10 minute DC values than the 3 or 7 minute values (P<.05), but some exceptions were observed in Duo-Link. Two-way ANOVA revealed that the influence of the zirconia disk thickness on the 10 minute DC was dependent on the light-curing methods (P<.001). This finding was still valid even at 4.0 mm thickness, where substantial light attenuation took place. CONCLUSION. The curing of the dual-cured resin cements was affected significantly by the light-curing technique, even though the additional chemical polymerization mechanism worked effectively.

• 천문학논총
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• 제7권1호
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• pp.89-96
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• 1992

Recent spectroscopic observations indicate concentration of dark masses in the nuclei of nearby galaxies. This has been usually interpreted as the presence of massive black holes in these nuclei. Alternative explanations such as the dark cluster composed of low mass stars (brown dwarfs) or dark stellar remnants are possible provided that these systems can be stably maintained for the age of galaxies. For the case of low mass star cluster, mass of individual stars can grow to that of conventional stars in collision time scale. The requirement of collision time scale being shorter than the Hubble time gives the minimum cluster size. For typical conditions of M31 or M32, the half-mass radii of dark clusters can be as small as 0.1 arcsecond. For the case of clusters composed of stellar remnants, core-collapse and post-collapse expansion are required to take place in longer than Hubble time. Simple estimates reveal that the size of these clusters also can be small enough that no contradiction with observational data exists for the clusters made of white dwarfs or neutron stars. We then considered the possible outcomes of interactions between the black hole and the surrounding stellar system. Under typical conditions of M31 or M32, tidal disruption will occur every $10^3$ to $10^4$ years. We present a simple scenario for the evolution of stellar debris based on basic principles. While the accretion of stellar material could produce large amount of radiation so that the mass-to-light ratio can become too small compared to observational values it is too early to rule out the black hole model because the black hole can consume most of the stellar debris in time scale much shorter than mean time between two successive tidal disruptions. Finally we outline recent effort to simulate the process of tidal disruption and subsequent evolution of the stellar debris numerically using Smoothed Particle Hydrodynamics technique.