• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1106-1108
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• 2009

TETRA(Terrestrial Trunked Radio)는 ETSI(European Telecommunications Standards Institute)에서 지정한 유럽 이동 무선 통신 기반의 표준이다. 본 논문은 TETRA 네트워크에서 트래픽에 따른 모뎀 성능 테스트와 그 결과 분석을 다룬다. TETRA 네트워크에서는 전송 방식에 따라 SDS(Short Data Service)와 PDS(Packet Data Service)로 나뉘게 되는데 본 논문에서는 PEI(Peripheral Equipment Interface)를 이용하여 SDS 전송 방식의 성능측정및 평가를 하였다. 본 측정에서는 최대 140바이트가 전송 가능한 SDS-Type 4가 사용 되었다. 성능 측정은 SDS메시지 데이터의 길이의 차이와 전송간격에 차이를 두어 측정하였다. 전송길이는 10에서 140바이트로 매 10바이트 단위씩 증가하였다. 전송 간격은 각각 0.5초, 1.0초, 1.5초씩 차이를 두어 측정하였고, 전송횟수는 각각 1000번씩 전송하였다. 테스트에 사용된 TETRA 모뎀은 UNIMO 사의 MU-1000MD이 사용되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1224-1227
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• 2008

송변전자동화시스템에서 사용하는 주장치 와 RTU간에는 무선 통신망으로 TRS(Trunked Radio System), CMDA(Code Division Multiple Access) 그리고 에어미디어망을 사용하고 있다. 특히 디지털 TRS기술인 유럽 전자 통신 표준기구인 ETSI에서 개발한 TETRA는 임대망인 CDMA와 에어미디어망과는 달리 비임대망으로 비용적인 장점을 가지고 있다. 본 논문은 송변전자동화시스템에서 주장치 기능을 하는 DNP3.0 주장치 서버와 RTU의 기능을 하는 FRTU간에 TETRA 망을 사용할 수 있도록 MFTG(Multi Function Tetra Gateway) Platform을 구현하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2985-2991
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• 2013

Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.576-581
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• 2008

High-quality double-walled carbon nanotubes (DWNTs) were synthesized without defects and amorphous carbonaceous particles by catalytic decomposition method at $800^{\circ}C$ in high yield. As-synthesized carbon materials almost consist of DWNT bundles with a diameter 12 - 20 nm.. The DWNTs rope have uniform diameter about 2 - 5 um and length up to several tens micrometer. DWNTs is inner tube diameter 0.9 - 1.5 nm and outer tube 1.6 - 2.2 nm. We investigate the crystallinity of DWNTs by TEM and Raman spectroscopy. We also found that the Fe-Mo bimetallic catalyst was active as a very efficient catalyst for the synthesis of DWNTs with the catalyst decomposition method. Our results also indicate that Tetra Hydro Furan (THF) is a very ideal carbon source for the synthesis of DWNTs.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1223-1225
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• 1995

The $NO_2$ gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett(LB) films of Copper-tetra-tert-butylphthalocyanine(CuTBP). The optimum conditions for a film deposition were obtained through a study of $\pi$-A isotherms, and the deposited film status was confirmed by the ellipsometry measurements. The $NO_2$ gas response experiments under 200 ppm concentration at room temperature show that there are increment of electrical conductivity by 40 times and 25 seconds of response time, and 40 seconds of recovery times.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.787-793
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• 2011

An efficient three-component one-step synthesis of 2,4,5-trisubstituted imidazoles by condensation reaction of 1,2-diketones or ${\alpha}$-hydroxyketones with aromatic aldehydes and ammonium acetate using Zinc (II) [tetra (4-methylphenyl)] porphyrin as a novel and reusable catalyst under ultrasound irradiation at ambient temperature is described. In this method, ${\alpha}$-hydroxyketones as well as 1,2-diketones were converted to their corresponding 2,4,5-trisubstituted imidazoles in excellent yields.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.179-182
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• 1995

The NO$_2$gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett(LB) films of Copper-tetra-tert-butylphthalocyanine(CuTBP). The optimum conditions for a film deposition were obtained through a study of $\pi$-A isotherms, and the deposited film status was confirmed by the ellipsometry measurements. It was found that at room temperature there are increments of electrical conductivities by 40 times, 25 seconds of response time and 40 seconds of response time when the films were exposed to the 200ppm NO$_2$gases. We hale observed an increase of the electrical conductivities as the density of NO2 gas increases.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.313-319
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• 2003

It is well known that ascorbic acid (VC) is an important factor for several physiological reactions. In the skin, VC works as an anti-aging agent due to removing of oxidative stress generated by UV irradiation and stimulation of collagen synthesis. Thus, developing more effective VC derivatives is an important issue in creating anti-aging skin care products. Our study succeeded to develop a novel ascorbic acid derivative, ascorbic acid tetra-2-hexyldecanoate (VC-IP), which is a lipid-soluble pro-VC. The purpose of this study was to indicate the effects of VC-IP as pro-VC and anti-aging agent. First, it was examined whether VC-IP is converted to VC in physiological conditions. Since VC was detected from the cell extracts treated with VC-IP, it was indicated that VC-IP is a pro- VC.(omiited)

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.477-480
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• 2008

A highly efficient white phosphorescent OLED with a "tetra-chromatic" emission was fabricated by using an external color tuning layer (ECTL) which is composed of a layer of greenish yellow organic dye dispersed in PMMA on the outside of the glass. The ECTL combining with a lower red dopant concentration in the device has been found to improve the efficiency of a conventional WOLED by more than 27%.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.217-222
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• 1998

A stereospecific HPLC method has been developed for the resolution of the enantiomers of salbutamol in human urine. After solid-phase extraction and derivatization with 2,3,4,6-tetra-O-acetyl-$\beta$-D-glucopyranosyl isothiocyanate, the diastereomeric derivatives were resolved (Rs=1.83) on $5{\mu}m$ octadecylsilan column using 35% acetonitrile in 0.05M ammonium acetate buffer (pH=6) as a mobile phase with electrochemical detection. The diastereomeric derivatives were formed within 30 min. The detection limit of each enantiomer was 20 ng/ml (S/N=3).