• 약학회지
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• 제53권6호
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• pp.342-350
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• 2009

The interaction of cadmium (II) ion with quercetin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to quercetin and (+)-catechin have been determined by UV-vis spectroscopy. 1 : 1 Cd (II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, due to a ligandto-metal charge transfer. These results suggest that Cd (II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• Journal of the Optical Society of Korea
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• 제10권1호
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• pp.33-36
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• 2006

This paper describes an efficient optimal design method for an arrayed waveguide grating (AWG) with flattened transfer function. The objective function is the norm of the difference between calculated and target spectra. To analyze the AWG transfer function, the Fresnel-Kirchhof diffraction formula was employed and the design variable was optical path difference of each array waveguide. The (1+1) Evolution Strategy was applied to an eight-channel coarse wavelength division multiplexing (CWDM) AWG as the optimization tool. The optimized transfer function will considerably improve the system performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1213-1215
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• 1994

The shape of lossy material inside a waveguide matched load is optimally designed to give low reflection over a given frequency range. The 3 dimensional vector finite element mettled is used as an analysis tool which does not generate spurious mode. The optimizing process used in this parer is the Powell technique. The designed load gives the low reflection about -30 dB around 10GHz with 1.5 wavelength of the load length.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.101-105
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• 2004

The laser ablation/ionization time-of-flight mass spectrometry is applied to the isotopic analysis of solid samples using a home-made instrument. The technique is convenient for solid sample analysis due to the onestep process of vaporization and ionization of the samples. The analyzed samples were lead, cadmium, molybdenum, and ytterbium. To optimize the analytical conditions of the technique, several parameters, such as laser energy, laser wavelength, size of the laser beam on the samples surface, and high voltages applied on the ion source electrodes were varied. Low energy of laser light was necessary to obtain the optimal mass resolution of spectra. The 532 nm light generated mass spectra with the higher signal-to-noise ratio compared with the 355 nm light. The best mass resolution obtained in the present study is ~1,500 for the ytterbium.

• 한국통신학회논문지
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• 제33권4C호
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• pp.336-341
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• 2008

본 논문에서는 신호의 반 파장 간격으로 안테나 소자를 배치한 빔형성 시스템에서 다이버시티 이득을 얻을 수 있는 빔형성 알고리즘을 제안한다. 제안된 알고리즘은 수신 신호 공간을 스팬(span)하는 고유 벡터들을 이용하여 빔형성 한다. 본 논문에서는 채널 추정을 위한 최적의 고유 공간 차수를 정하기 위한 기준도 제안한다. 제안된 알고리즘을 적용한 빔형성 시스템은 기존의 빔형성 시스템과는 달리 각 퍼짐이 증가함에 따라 다이버시티 이득을 얻어 그 성능이 개선된다. 본 논문은 제안된 알고리즘의 설명과 함께 다양한 컴퓨터 시뮬레이션을 통한 제안 알고리즘의 성능 분석을 제공한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.173-176
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• 1997

The III-V nitride semiconductor InN thin films which have the direct bandgap in visible light wavelength region have been deposited on Si(100) substrates and AIN/Si(100) substrates by rf reactive sputtering. InN thin films have been investigated on the structural, and electrical properties according to the sputtering parameters such as total pressure, rf power, and substrate temperature. It is found that optimal conditions required for fabricating InN thin films with high crystal Quality, low carrier concentration, high Hall mobility are total pressure 5mTorr, rf power 60W, substrate temperature 6$0^{\circ}C$ . InN thin films deposited on the AIN(60min.)/Si(100) substrates arid AIN(120min.)/Si(100) substrates showed remarkably high crystal quality and electrical properties. It is known that AIN buffer layer is to decrease free energy at interface between InN film and Si substrate, and then promoting lateral growth of InN films.

• 한국전기전자재료학회논문지
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• 제16권2호
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• pp.131-137
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• 2003

We have performed computer simulation to obtain electro-optic chracteristics of reflective liquid crystal display (LCD) using wide viewing angle LC mode, fringe field switching(FFS). Unlike other reflective LCD modes, in the FFS mode, the LC director in plance so an application to reflective display consisted of polarizer, LC layer and reflector is possible. when an incident light is 550mm, the optimal cell retardation value is 0.1365${\mu}$m and the efficiency of reflectivity is high over 90% with very little wavelength dispersion. Further, we have studied a new reflective display with polarizer, optical compensation film with half plate, LC plus reflector. The display with optimized cell parameters shows high contrast ratio (CR) over 130 with high light efficiency over 90% at normal direction and the CR greater than 5 exists over 60$^{\circ}$ of polar angle in all directions.

• 한국정밀공학회지
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• 제25권5호
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• pp.89-95
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• 2008

The Acousto-Optic Tunable Filter (AOTF) is a high-speed full-field monochromator which generates two spectrally filtered light beams with ordinary and extraordinary polarization state. Thus, AOTF is widely used to build full-field spectral imaging system or spectral domain interferometer. However, AOTF has a big problem that the angle of diffracted light changes according to the scanning of wavelength, which makes image shift on CCD plane In this paper, we propose an analytic design of prism system to compensate the image shift. The detailed analysis of light paths in a prism and basic experimental results are presented to verify our proposed compensation method. The experimental results agree with simulation results based on suggested prism model and image shift is minimized at optimal condition. Also, it can be extended to compensate the image shift for ordinary and extraordinary polarized light simultaneously.

• 대한원격탐사학회지
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• 제17권4호
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• pp.297-305
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• 2001

Ocean satellite altimetry-implied free-air gravity anomalies have had the shortest wavelengths removed during the processing to generate the optimal solution between multiple radar altimeter missions. ERS-1 168day mission altimetry was residualized to a reference geoid surface generated by integrating Anderson & Knudsen’s free-air gravity anomalies for the Barents Sea. The altimetry tracks were reduced and filtered to extract the shortest wavelengths (between 4 and 111 km) from both ascending and descending tracks, respectively. These data were recombined using existing quadrant-swapping techniques in the wavenumber domain to generate a correlated, high frequency gravity field related to the local geologic sources. This added-value surface adjusted the reference free-air gravity anomalies to better reflect features in the gravity field at a wavelength related to the distance between altimetry ground tracks.

• Journal of the Optical Society of Korea
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• 제7권1호
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• pp.28-33
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• 2003

We describe the optimal design and the fabrication of a 2$\times$2 port optical device based on the thin film filter (TFF), and also propose a 4-channel OADM module using these devices. The optical performance of the proposed OADM module is evaluated theoretically and experimentally, and is compared to that of typical OADM modules using 1$\times$2 port optical devices for 4, 8, 16 and 32 drop channels in optical transmission systems. Since the 2$\times$2 port optical device accomplishes the function of wavelength multiplexing and demultiplexing simultaneously in the proposed OADM module, the insertion loss of through channels can be improved by 1.2 dB compare to that of typical OADM modules using 1$\times$2 port optical devices. In addition, both the size and the price of the module can be reduced to 40~50%.