• Analytical Science and Technology
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• v.11 no.2
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• pp.96-104
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• 1998

A photodiode array multichannel detector system for capillary electrophoresis was developed. The photodiode array detector for capillary electrophoresis (CE-PDA) has 1024 photodetectors and can analyze sample by measuring UV/VIS absorption spectrum in 275~675 nm wavelength range. The CE-PDA instrument can get a spectrum in 30 ms during sample separation and can be programmed by a PC to control various experimental conditions required for sample analysis. The performance of the multichannel CE-PDA instrument was tested using L-ascorbic acid and alizarin yellow GG mixture. The reproducibility test of the CE-PDA system showed 5.6% RSD.

• Korean Journal of Materials Research
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• v.26 no.4
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• pp.212-215
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• 2016

In this paper, cerium doped lutetium pyrosilicate (LPS) powders with cerium content (0.05 and 0.07 mol%) were prepared by sol-gel process. The formation of lutetium pyrosilicate (LPS) phase was confirmed by XRD analysis for the powders heated at $1,200^{\circ}C$; in these powders, a single phase of $Lu_2Si_2O_7$ (LPS) was observed. Cerium doped lutetium pyrosilicate (LPS) powder was agglomerated and constituted of small spherical particles with diameters of about 300 nm. The photoluminescence spectra of the $Lu_2Si_2O_7:Ce^{3+}$ powders showed the characteristic of excitation and there was an emission spectrum for $Ce^{3+}$ in the host of $Lu_2Si_2O_7$. The emission spectrum shows a broad band in the range of 350-525 nm; the broad wavelength on the right side of the spectra should be ascribed to the same 5d-4f transitions of $Ce^{3+}$, as in the case of cerium doped $Lu_2Si_2O_7$ single crystals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.84-87
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• 2003

HgTe quantum dots(QDs) were synthesized in aqueous solution by colloidal method. The absorption and photoluminescence(PL) spectrum of the synthesized HgTe QDs revealed the strong exitonic peak in the IR region. And the photocurrent measurement of colloidal QDs are performed using IR light source. The lineshape of the wavelength dependent intensity of photocurrent was very similar to the absorption spectrum, indicating the charges generated by the absorption of photons give direct contribution to photocurrent. The channels of dark current are supposed $H_2O$ containing in thiol by the remarkable drop of current at the state of vacuum. It was thought that the proper passivation layer on the top of HgTe film reduce the dark current and the adequate choice of capping material improves the efficiency of the photocurrent in the HgTe QDs. This study suggests that HgTe QDs are very prospective materials for optoelectronics including photodetectors in the IR range.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.15-24
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• 1997

We propose a tunable add/drop filter in a form of an all-fiber mach-zehnder interferometer iwth one bragg grating at each arm. This device can be tuned by inducing a strain in the bragg grating. We also theoretically analyze the outut characteristics of the tunable add/drop filter. As a result of simulation, we know that the proposed tunable add/drop filter works well. When 2*10$^{-3}$ of strain is induced, the reflected spectrum shifts about 3nm. And its reflected spectral width is about 0.3nm. In this case roughly 5 channels can be tuned, assuming the channel spacing is 0.3nm. When the pathlengths of the both arms are not the same, the transmissivities at the add and output ports and the reflectivity at the tap port varies sinusoidally with the pthlength difference. To maintain the transmissivities above 90% in the wavelength tuning range of 20nm the pathlength difference less than 16.mu.m is required.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.811-816
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• 2004

The tactile force sensor was studied using Fiber Bragg Grating (FBG). The FBG is able to multiplex easily and is immune to electromagnetic environment. A sensor frame was designed to a cantilever beam type. Strain of a beam is related with the peak shift of a bragg wavelength. Finite Element Method (FEM) was used for getting an appropriate thickness from 0.2 mm to 0.3 mm thick. FEM results showed that 0.3 mm thick was suitable for the force range 10 N. The force resolutions of 0.039 N and 0.113 N were obtained with optical spectrum analyser and tunable Fabry-Perot filter, respectively.

• Journal of Photoscience
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• v.12 no.3
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• pp.143-147
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• 2005

The simultaneous determination of harman, harmaline and norharman has been described using synchronous fluorescence technique. The method has been based on their natural fluorescence. It is difficult to analyze and determine their contents by conventional fluorescence method because of their similar molecular structures. The synchronous spectrum, maintaining a constant wavelength difference of ${\Delta}{\lambda}=185nm$ between the excitation and emission monochromators, was selected as optimum to perform the determination. The method was also performed in aqueous medium at pH 4.0 and in presence of sodium dodecyl sulfate (SDS), $1{\times}10^{-5}M$. Under the optimum conditions, each analyte has the linear determination range of $1{\times}10^{-7}M-\;1{\times}10^{-4}M$.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.53-57
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• 2011

We developed a small methane detection system because methane gas is used in many areas and is dangerous. The developed system consisted of LD(Laser Diode) tuned a wavelength of $1.65\;{\mu}m$, two mirrors to collect a laser beam, photo detector. It could detect methane gas at a long range and its sensitivity was 1.98 V/$CH_4%$.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.507-512
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• 2000

The main objective of this study is to provide a soil surface information, which represent a soil reflectance spectrum, by remote sensing technology. The soil reflectance of the soil was measured using a spectroradiometer in the wavelength range from 300nm to 1100nm. Measurements of soil reflectance have been made in four different soils. The results suggest that the reflectance properties of soils are related to their mineral composition and soil moisture. Increasing soil moisture resulted in an decrease in the rate of reflectance which leads to parallel curves of soil reflectance spectra. The soil line representing the relationship between red and near-infrared soil reflectance is characterized by soil types.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.80.1-80.1
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• 2012

The $2.5-5.0{\mu}m$ spectrum of AGN was poorly understood due to the atmosphere effect beyond $2{\mu}m$. Nevertheless, the $2.5-5.0{\mu}m$ range includes several important lines, such as $Br{\beta}$ ($2.63{\mu}m$), $Br{\alpha}$ ($4.05{\mu}m$), PAH (3.3${\mu}m$) and many molecular or atomic lines. We compile $2.5-5.0{\mu}m$ spectra of 79 AGNs and QSOs from infrared camera (IRC) on AKARI infrared astronomy satellite. Our $2.5-5.0{\mu}m$ spectra will provide an access to full wavelength spectra of AGNs for the first time. Moreover, we present the Brackett line properties, FWHMs and luminosities, of AGNs. Using these Brackett line properties, we derive new black hole (BH) mass estimators. The new BH mass estimators using NIR hydrogen lines will be very useful to estimate BH mass of dusty red AGNs in the future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.95-98
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• 2003

Tin doped indium oxide(ITO) films, which is widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. The influence of the substrate temperature, working gas pressure and deposition time on the electrical, optical and morphological properties were investigated experimentally. ITO films with the optimum growth conditions showed resistivity of $2.36{\times}10^{-4}(\Omega}-cm$ and transmittance of 86.28% for a film 680nm thick in the wavelength range of the visible spectrum.