• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.472-478
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• 2001

We determined the optical constants and thickness of organic electroluminescence thin films using variable angle spectroscopic ellipsometry. Using the measured transmittance spectra and the spectroscopic ellipsomeoy data of the organic films on glass substrates in the optically transparent region, we determined the effective thickness and the refractive indices of organic thin films. Then by applying a numerical inversion method to variable angle spectro-ellipsometry data, we determined the complex refractive index at each wavelength including the optically absorbing region, as well as the thickness and surface micro-roughness of the organic thin films. The calculated transmittance spectra showed a tight agreement with the measured ones, confining the validity of the present model analysis.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.279-282
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• 2010

스티로폼샌드위치패널은 건식공법의 시공편리성, 경제적인 공사비용, 뛰어난 단열성능으로 공장이나 창고건축물을 중심으로 많이 사용되고 있다. 그러나 스티로폼의 여러 가지 장점에도 불구하고 화재에 취약한 단점이 있어 최근 난연성능이 보완된 난연스티로폼패널의 사용이 증가하고 있다. 최근 건축현장에서, 가짜 난연스티로폼패널 사용이 문제되고 있으나 난연성능의 현장 확인에 어려움이 있고 콘칼로리미터 등의 난연성능평가에 시간과 비용이 소요된다. 본 연구에서는 콘칼로리미터를 통해 난연성능이 확보된 난연 스티로폼패널의 심재와 일반스티로폼패널 심재를 대상으로 근-적외선 분광분석을 수행하여 난연성능의 유무에 따라 상이하게 나타나는 고유스펙트럼 흡수를 측정하였다. 각 제품마다 측정된 고유스펙트럼은 통계처리를 통하여 난연스티로폼의 진위여부를 현장에서 구별할 수 있음을 확인하였으며, 비용효율이 높은 현장평가방법으로의 적용이 가능함을 실험을 통해 입증하였다.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.19-25
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• 2003

A spectrophotometric method for the simultaneous determination of anionic and nonionic surfactant based on the application of multivariate calibration method such as principal component regression(PCR) and partial least squares(PLS) has been studied. The calibration models in PCR and PLS were obtained from the spectral data in the range of 400~700 nm for each standard of a calibration set of 26 standards, each containing different amounts of two surfactants. The relative standard error of prediction(RSEP$_{\alpha}$) was obtained to assess the model goodness in quantifying each analyte in a 5 validation samples which containing different amounts of two surfactants.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.58-62
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• 2001

The L $i_{0.5}$F $e_{2.5-x}$A $l_{x}$ $O_4$ systems (x=0, 0.3, 0.6, 0.9, 1.2, 1.5) were investigated by X-ray diffraction and Mossbauer spectroscopy. The structure of all the samples is cubic spinel type and lattice constant decrease with increasing Al content x. The Moissbauer spectra reveal two sextet for 0$\leq$x$\leq$0.6, two sextet and a doublet for 0.9$\leq$x$\leq$1.2, and a doublet for x=1.5. The cation distribution of the samples is (L $i_{1-a}$$^{+}$F $e_{a}$ $^{3+}$)$^{A}$[L $i_{a-0.5}$$^{+}$A $l_{2.5-a-x}$$^{+}$F $e_{2.5-a-x}$$^{3+}$]$^{B}$ $O_4$$^{2-}$ and substituted $Al^{3+}$ ions decrease the covalency of F $e^{3+}$- $O^{2-}$ bond in B-sites and A-B super-exchange interactions.tions.s.tions.ons.s.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.249-253
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• 2004

CdS semiconductor quantum dot (QD) structures in aqueous solution are fabricated by using a gamma-ray irradiation technique and their optical absorption spectra are investigated. Cadmium sulfate solution, 2-mercaptoethanol solution, and reducing agent $e^{-}_{aq}$ are employed to produce CdS molecules, leading to CdS quantum dots. The measured linear absorption spectra before and after g-ray irradiation clearly show exciton peaks between 300 nm and 400 nm, which indicate the formation of CdS QD's. It is also observed that the exciton peaks are red-shifted with increasing the g-ray irradiation time from 5 min to 15 min. Therefore, it is concluded that the mean QD sizes can be systematically controlled with the dosage of the g-ray irradiation.

• Analytical Science and Technology
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• v.14 no.3
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• pp.197-202
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• 2001

The characteristics of the electrochemically Li intercalated synthetic graphite were determined from the studies with XRD method, DSC and solid $^7Li-NMR$ spectrophotometric analysis. From the results of X-ray diffraction method, it was found that the compounds in the stage 1 structure were predominantly formed. The enthalpy and entropy changes of the compounds can be obtained from the differential scanning calorimetric analysis results. From these results, it was found that exothermic and endothermic reactions of lithium intercalated into synthetic graphite are related to thermal stability of lithium ion between carbon graphene layers. From the $^7Li-NMR$ data, scientific observation found that bands are shift toward higher frequencies with increasing lithium concentration because non-occupied electron shells of Li increased in charge carrier density. Line widths of the Li intercalated synthetic graphite compounds decreased slowly because of non-homogeneous local magnetic order and the random electron spin direction for substituted Li.

• Analytical Science and Technology
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• v.12 no.3
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• pp.209-217
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• 1999

To elucidate the decay of the rose bengal (RB) sensitized and thiourea (TU) supersensitized photocurrent, spectroscopic analyses of the dye solution were performed. Absorption and fluorescence spectroscopic analyses of sensitizing solution before and after irradiation enabled to conform the new mechanism of the photocatalytic dimerization between RB and TU. And it was also found that the geometrical arrangement of the transition dipole moment is oblique and the angle between the dipoles is $124^{\circ}$ in the dimer of dye molecules.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.167-173
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• 2000

Four glasses of $B_2O_3-Bi_2O_3-PbO-SiO_2$ (BBPS) system were prepared by melting the appropriate amounts of reagent grade oxides of $B_2O_3$, $Bi_2O_3$, PbO, and $SiO_2$ in an open crucible. The differential thermal analysis showed crystallization temperature decreased with increasing $Bi_2O_3$ or PbO content in the sample. The structures of glasses system were studied using scanning electron microscopy and Fourier transform-Infra red (FT-IR) spectroscopy. The UV cut-off and refractive index were found to be sensitive to the $Pb^{+2}$ and $Bi^{+3}$ content in the glasses. The behavior of the IR spectra of the glasses in the BP series was consistent with a role of $Bi_2O_3$ as a network former. In the BP series of glasses, the result of IR spectrum indicated that PbO behaved as a network former.

• Journal of the Korean Chemical Society
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• v.24 no.6
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• pp.444-451
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• 1980

In order to further elucidate the process of electron solvation in liquids, the medium effect, as the difference between the free energy of $H^+$ in aqueous and non-aqueous states (${\Delta}{\Delta}G_0$), of THF-water mixtures has been investigated. (${\Delta}{\Delta}G_0$) were determined by electromotive force masurements of the cell Pt$H_2Q$, Q, HCI, THF, $H_2O$|KC1 | $Hg_2Cl_2$|Hg(Pt), where $H_2Q$ and Q are hydroquinone and quinone respectively. The effect of dielectric constant on the difference of free energy and the absorption energy of solvated electrons have been studied. For the consideration of these effect the polymerization of water in THF has been studied. Near infrared spectrum of O-H stetching energy has been used to measure the extent of water aggregates. The expermental results indicate that at least in some composition of binary mixtures the electrons or other ions are solvated preferentially with one component of solvents.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2273-2279
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• 2012

This research is based on fabricating Cu(In,Ga)$Se_2$ thin-film by co-evaporation method. On $1^{st}$ - stage, $In_2Se_3$ phase appeared when the substrate temperature reached to $400^{\circ}C$, however, there was small effect between the substrate temperature and absorbency spectrum on $2^{nd}$, $3^{rd}$ - stage because the average thickness of the thin-film was $1{\mu}m$ or higher. SEM and XRD was measured on $2^{nd}$ and $3^{rd}$ stage and it showed as the substrate temperature increases, the density of the crystal structure increased with the decreament of the vacancy. Furthermore, the formation of Cu(In0.7Ga0.3)$Se_2$ phase showed at $480^{\circ}C$ and $500^{\circ}C$.