• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.433-439
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• 2005

We have developed a biosensor reading system using a white light source and a color-sensor. To reduce the environmental effect, we used the ratio of specific color intensity to the entire white light intensity. Also we could improve the responsibility of the system by controlling the amplification of the color sensor output.

• Journal of The Korean Association For Science Education
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• v.18 no.3
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• pp.303-312
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• 1998

In this study, the multimedia CAl program for chemical equilibrium in high school grade 3 was developed and the effect of CAl on achievement and attitude toward chemistry instruction and computer was investigated. Before instruction, the test of attitudes toward chemistry instruction and computer were administered, and the grade in the mid-term examination was obtained. These scores were used as covariates. Mid-term science score was used as blocking variable. For chemical equilibrium instruction, traditional and computer assisted instruction were used. After instruction, the achievement test and the test of attitudes toward science instruction and computer were administered. The results indicated that students in the treatment group achieved significantly better than those in the control group, but did not show improvement of attitude to chemistry instruction and computer compared to those in the control group. No significant interaction between the treatment and the level of students' prior achievement was found. Female achieved significantly better under CAl than under traditional instruction. In two subtests(understanding and application), treatment group achieved better in the subtest of application than control group. CAl had an effect on chemical equilibrium state (about reversibility) significantly. While female of the treatment group did not show more positive attitude toward both chemistry instruction and computer significantly than that of the control group, male showed more positive attitude significantly. Educational implications are discussed.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.698-704
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• 2005

Power consumption for paddle impeller in spherical and cylindrical agitated vessel was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation was obtained for both spherical and cylindrical vessels, where the apparent diameter of the spherical vessel was equal to the diameter of the cylindrical vessel (height equal to its diameter and had the same volume as the spherical vessel). The power consumption well correlated with the experimental results of Nagata, et al. and Hixson-Baum. Also the critical Reynolds numbers was directly related to the transition coefficient $C_{tr}$ characterizing the transition from a laminar to a turbulent flow region in the correlation proposed here.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.575-575
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• 2013

Indium Zinc Oxide (IZO)는 가시광 영역(380~780 nm)에서 높은 투과율과 적외선영역에서 높은 반사율을 보이는 투명산화막으로서 Flexible display 적용으로 주목 받는 재료이다. 특히 비 화학적 양론비(non-stoichiometric)로 성장된 박막은 N형 반도체 특성을 갖기 때문에 광전자 소자, 액정표시소자와 태양전지의 투명전극 재료로 이용되고 있으며, 향 후에도 수요는 계속 증가될 전망이다. 일반적으로 IZO 박막은 높은 열처리 온도에 의한 기판재료의 선택이 한정적인 단점이 있다. 따라서 최근에는 정밀하게 제어된 에너지를 가진 전자를 표면에 조사(E-beam irradiation)하여 박막의 물성을 개선하고 기판재료의 선택성을 넓히는 연구가 활발히 진행되고 있다 [1]. 본 연구에서는 RF Magnetron Sputtering 법을 이용하여 Glass 위에 IZO를 증착하였다. 스퍼터링타겟은 고순도 IZO 타겟을 이용하여 100 nm의 두께를 가지는 박막을 증착하였다. 증착된 IZO 박막에 E-beam Source ((주)인포비온)를 이용하여 E-beam irradiation energy 조건에 변화를 주어 박막의 물성 변화를 관찰하였다. IZO 박막의 두께를 측정하기 위해 SEM (Cross section)을 이용하였다. E-beam irradiation energy에 따른 가시광 영역(380~780 nm)에서의 광투 과도는 UV-Vis spectrometer를 사용하여 측정하였고, 전기적인 특성은 Hall measurement system 을 이용하여 측정하였다. 또한 박막의 결정성과 거칠기의 변화는 XRD (X-ray Diffraction)와 원자 간력현미경(Atomic Force Microscope; AFM)을 이용하여 측정하였다. Rf magnetron Sputtering 법을 이용하여 증착한 IZO 박막에 Post E-beam irradiation이 전기전도 및 광 투과특성과 결정성과 표면 조도를 향상시키는데 크게 기여함을 확인할 수 있었다.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.246-251
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• 1997

The phase behavior of sucrose monopalmitate/alkanol/water ternary system was investigated. According to compositions of three components ranging from micellar(or inverse micellar) solution up to various lyotropic liquid crystalline(LC) phase, each texture of the separated phases was identified by crossed polarizers equipped with a camera whose stage was connected to a thermostatic circulator. As the carbon atom number in alkanol of the polar oily substance increases, patterns of the various LC phases were also observed hexanol

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.397-400
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• 2010

Unstructured adaptive grid flow simulation is applied to the calculation of high speed compressible flow of inert and reactive gas mixtures. Computational results are presented for the case of premixed hydrogen-air supersonic flow over a 2-D wedge. In such a configuration, combustion may be triggered behind the oblique shock wave and transition to an oblique detonation wave is eventually obtained. It is shown that the solution adaptive procedure implemented is able to correctly define the important wave front.

• Economic and Environmental Geology
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• v.34 no.1
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• pp.71-88
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• 2001

The Geochemica] and isotope studies on the $CO_2$-rich water from the Shinchon area were carried out. The Shinchon $CO_2$-rich water belongs to Ca(Na)-$HCO_3$ type showing very high $P_{CO_{2}}$ ( $10^{-0.35}$ ~ $10^{0.29}$ atm) and TDS (835-3,144 mg/L). The results of geochemical and isotope analysis indicate that $CO_2$ gas is originated from the deep seated source such as mantle or magmatic gases. The $CO_2$-rich water was evolved by interaction with deep-seated granite and major water-rock interaction was dissolution of p]agioclase resulting high Na content of $CO_2$-rich water. Precipitation and dissolution of secondary calcite might be accompanied with the dissolution of plagioclase maintaining Na/Ca ratio. High contents of K and $SO_4$ indicate that the geochemical characteristics of $CO_2$-rich water were partially affected by interaction with upper sedimentary rock during uprising to surface. N03 and tritium contents suggest that the $CO_2$-rich water was mixed with low $CO_2$ groundwater at some locations. The oxygen-hydrogen isotopes show that all water samples were derived from meteoric waters and the $CO_2$-rich water was isotopically re-equilibrated with lighter $CO_2$ gas. Although some carbon isotope data show isotopically heavy values, carbon isotope data indicate that the $CO_2$ gas was possib]y derived by deep source.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.459-475
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• 2004

The geology of the Kualakulun area in Middle Kalimantan, Indonesia comprises Permian to Carboniferous Pinoh Metamorphic Rocks and Cretaceous Sepauk Plutonics of the Sunda Shield, late Eocene Tanjung Formation, Oligocene Malasan Volcanics, Oligocene to early Miocene Sintang Intrusives and Quaternary alluvium. Sepauk Plutonic rocks are classified as the calc-alkaline series and the S-type granite. Sintang Intrusive rocks are basic-intermediate and intermediate rocks, and consists of basalt, basaltic andesite, basaltic trachyandesite and trachyandesite. The Malasan Volcanics are characterized by intermediate dacitic pyroclasticl and minor lavas and belong to the subalkaline (calc-alkaline and tholeiitic) series. The whole-rock K-Ar ages of the fine-grained biotite granites and medium-grained granitoids were determined to be 100.5-106.5 Ma and 91.9-102.6 Ma, respectively. The whole-rock K-Ar age of the diorite is 89.1 Ma. K-Ar ages of the Malasan Volcanics and Shintang intrusives show 31.5-36.8 Ma and 24.6-34.5 Ma, respectively, and correspond to the Tertiary time.

• Journal of the Korean Chemical Society
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• v.39 no.6
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• pp.446-452
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• 1995

Lithium intercalates, $Li_xFeMoO_4Cl$ ($1{\leq}X{\leq}2$) prepared by electrochemical lithiation of $FeMoO_4Cl$ crystallizes in monoclinic structure for all x values as revealed by x-ray diffraction and galvanostatic discharge experiments. According to the x-ray photoelectron spectroscopic study, Fe(III) is at first reduced to Fe(II) upon lithium intercalation with the x domain of $0{\leq}X{\leq}1$, where the crystal symmetry is changed from tetragonal to monoclinic. On the other hand, Mo(VI) is reduced to lower valent state upon further lithium intercalation ($1{\leq}X{\leq}2$), where no crystal symmetry transformation and reduction of Fe(II) to lower valent state are observed. The Mo 3d spectrum for $Li_2FeMoO_4Cl$ appears as a complex shape, but can be deconvoluted into the three sets of the doublet on the basis of Gaussian function, those which correspond to Mo(VI), Mo(V) and Mo(IV) states, respectively. The mixed valent states of molybdenum after further lithiation may be due to a competitive reaction between the formation of Mo(V) and its disproportionation to Mo(IV) and Mo(VI).

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.295-303
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• 2003

Sorption kinetics of hydrophobic organic compounds (chlorobenzene and phenanthrene) in natural wetland soils was investigated using laboratory batch adsorbers. One -site mass transfer model (OSMTM) and two compartment first-order kinetic model (TCFOKM) were used to analyze sorption kinetics. Analysis of OSMTM reveals that apparent sorption equilibria were obtained within 10 to 75 hours for chlorobenzene and 2 hours for phenanthrene, respectively. For chlorobenzene, the sorption equilibrium time for surface soil was longer than that of deeper soil presumably due to physico-chemical differences between the soils. For phenanthrene, however, no difference in sorption equilibrium time was observed between the soils. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM in describing sorption kinetics, The fraction of fast sorption ($f_1$) and the first-order sorption rate constants for fast ($k_1$)and slow ($k_2$) compartments were determined by fitting experimental data to the TCFOKM. The results of TCFOKM analysis indicate that the sorption rate constant in the fast compartment($k_1$) was much greater than that of slow fraction($k_2$) . The fraction of the fast sorption ($f_1$) and the sorption rate constant in the fast compartment($k_1$) were increasing in the order of increasing $k_{ow}$, phenanthrene > chlorobenzene. The first-order sorption rate constants in the fast ($k_1$) and slow ($k_2$) compartments were found to vary from $10^{-0.1}\;to\;-10^{1.0}$ and from $10^{-4}\;to-10^{-2}$, respectively.