• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.84-91
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• 2008

The spectral radiance received by a remote sensor at a given temperature and wavelength region is consisted of the self-emitted component directly from the object surface, the reflected component of the solar irradiation at the object surface, and the scattered component by the atmosphere without ever reaching the object surface. The IR image of a ship is mainly affected by location, meteorological condition(atmosphere temperature, wind direction and velocity, humidity etc.), atmospheric transmittance, solar position and ship surface temperature etc. Computer simulations for prediction of the IR signatures of ships are very useful to examine the effects of various meteorological conditions. In this paper, we have acquired the IR signature for different meteorological conditions by using two different computer programs. The numerical results show that the IR image contrast as compared to the background sea considering the atmosphere temperature and wind velocity.

• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.59-66
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• 2022

A free-form Mueller matrix ellipsometer (MME) based on independent control of the azimuthal angle of each polarizing element is introduced. The azimuthal angles of the polarizer and the matching compensator which generate the optimum Stokes vectors of an incident beam are investigated for the polarization state generator, where the spectral responses of the retardation angle and transmittance ratio of a nonideal compensator are taken into account. Similarly, the azimuthal angles of the analyzer and the corresponding compensator are investigated for the polarization-state detector, to unambiguously determine the Stokes vector of the outcoming beam from the sample, and explicit expressions for the Stokes elements are derived. Since the suggested technique enables one to utilize a nonideal quarter-wave plate as the compensator for an MME, it will contribute to the construction and application of a Mueller matrix spectroscopic ellipsometer (MMSE) operating over a wide spectral range from deep ultra-violet to near infrared.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.168-172
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• 1993

We measured the spectral transmittance of the cholesteric mixtures of ZLI-1167 and CB15 for various weight fractions of CB15 in the mixture to find out the relationship between the center wavelength of the selective reflection band and the weight fraction of CB15 in the mixture. Left handed circular polarizer for 632.8 nm was designed and fabricated with this mixture whose weight fraction of CB15 was 33.19%. The ellipticity of the elliptical polarization of the transmitted light was measured to be 0.98 showing excellent property of the CLC circular polarizer.

• Journal of the Korean Vacuum Society
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• v.8 no.4A
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• pp.438-444
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• 1999

The characterization of the reactively sputtered ITO layer on the PET film has been studied. The PEM device has been used to determine the optimum stoichimetry through control of the amount of oxygen incorporated into the alloy target and the optimum operation conditions to produce films with the highest electrical conductivity and visible transparency. The PEP film was pre-treated under the plasma discharge condition to remove the adsorbed gases and to modify the surface morphology. The results revealed that by adjusting the flow rate of oxygen with the spectral intensity of indium target, the composition of plasma gas can be kept constant during the entire deposition period. The resistivity of ITO film obtained was fond to be about 37$\Omega\Box$, and the transmittance of visual range was about 86%.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.62-70
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• 1997

In this paper, the optical conditins of a reflective multi-color STN-LCD based on electrical control of birefringence is designed on the poincare sphere. First of all, the angles of polarizer and analyzer for the best color purity are decided in the configuration without a retardation film. A retardation film is introduced for a bright white in the range of the applied voltage. The sretardation and the angle of the retardation film are also decided on the poincare shpere. The test cell is farbricated and its measured spectral transmittance and the CIE chromaticity diagram agree well with simulations.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.295-308
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• 2000

OSMI(Ocean Scanning Multi-Spectral Imager) raw image data(Level 0) were acquired and radiometrically corrected. We have applied two methods, using solar & dark calibration data from OSMI sensor and comparing with the SeaWiFS data, to the radiometric correction of OSMI raw image data. First, we could get the values of the gain and the offset for each pixel and each band from comparing the solar & dark calibration data with the solar input radiance values, calculated from the transmittance, BRDF (Bidirectional Reflectance Distribution Function) and the solar incidence angle($\beta$, $\theta$) of OSMI sensor. Applying this calibration data to OSMI raw image data, we got the two odd results, the lower value of the radiometric corrected image data than the expected value, and the Venetian Blind Effect in the radiometric corrected image data. Second, we could get the reasonable results from comparing OSMI raw image data with the SeaWiFS data, and get a new problem of OSMI sensor.

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.499-504
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• 1989

Coloring effect, mechanical properties resulting from silver ions exchange of glasses immersed into the mixed molten salt of KNO3 and AgNO3 were investigated in this study. Ion exchange coloring of glasses made it possible to obtain glasses with a range from yellow to yellowish-brown, and spectral transmittance was investigated. The amount of ion exchange and peneration depth increased with treatment temperature and time. The activation energy decreased with mole fraction of AgNO3. It can be seem that the bending strength of ion exchanged glasses were 3~4 times higher than the parent glass and Ag+ colloids prevented from increasing surface microhardness.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2895-2898
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• 2009

The complete structural characterization of dehydrodivanillin, an important natural product of interest to the food, cosmetics and aroma industries, has been carried out using multi-dimensional NMR spectroscopic techniques, and its previously $reported^{13}$C-NMR values have been reassigned. Dense and granular thin films of dehydrodivanillin have been grown by sublimation under high vacuum and studied using Scanning Electron Microscopy (SEM), electrical and optical techniques. The transmittance spectra of the films indicate a wide optical band gap of more than 3 eV. Typical J-V characteristics of Glass/ITO/dehydrodivanillin/Al structure exhibited moderate current densities ${\sim}10^{-4}\;A/cm^2$ at voltages > 25 V with an appreciable SCLC mobility of the order of $10^{-6}\;cm^2$/V-s.

• YAKHAK HOEJI
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• v.47 no.5
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• pp.261-265
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• 2003

Near-infrared (NIR) system was used to determine rapidly and simply indomethacin in buffer solution for a dissolution test of tablets and capsules. Indomethacin standards were prepared ranging from 10 to 50 ppm using the mixture of phosphate buffer (pH 7.2) and water (1 : 4). The near-infrared (NIR) transmittance spectra of indomethacin standard solutions were collected by using a quartz cell in 1 mm and 2 mm pathlength. Partial least square regression (PLSR) was explored to develop calibration models over the spectral range 1100∼1700 nm. The model using 1 mm quartz cell was better than that using 2 mm quartz cell. The PLSR models developed gave standard error of prediction (SEP) of 0.858 ppm. In order to validate the developed calibration model, routine analysis was performed using another standard solutions. The NIR routine analysis showed good correlation with actual values. Standard error of prediction (SEP) is 1.414 ppm for 7 indomethacin samples in routine analysis and its error was permeable in the regulation of Korean Pharmacopoeia (VII). These results show the potential use of the real time monitoring for indomethacin during a dissolution test.

• Journal of the Korean Ceramic Society
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• v.27 no.6
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• pp.763-768
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• 1990

The gradient and depth of tin at the side of glasses by float process were measured. The effects of tin to ion exchanged of glasses in the molten salt of KNO3 and AgNO3 were presented by means of Ag+ ion penetration depth, diffusion coefficient variation, spectral transmittance and color coordinates. The diffusion coefficient of Ag+ ion of tin side was higher than air side, and the activation energy of tin side was 0.2-0.6Kcal/mole lower than air side. Therefore Ag+ ion penetration depth of tin side is 2-10$\mu\textrm{m}$ deeper, hence it can be seen that tin promote Ag+ ion diffusion. The same treatment of ion exchange, reddish-brown oflong wavelength in case of tin present, yellowish-amber of short wavelength in case of tin absence were revealed.