• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.161-168
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• 2009

We demonstrated $\check{S}$olc-type wavelength filters in periodically poled Ti-diffused lithium-niobate channel optical waveguide (Ti:PPLN). A $\check{S}$olc-type transmission spectrum based on the polarization-mode conversion was observed experimentally in PPLN with period 16.6${\mu}m$. A reasonable explanation of such a phenomenon was presented. A polarization-mode converted transmission peak was observed at wavelength 1272.49nm. The FWHM and sidelobe of spectrum are about 0.23nm and 7 dB, respectively.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.698-703
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• 1998

The pervaporation experiments of aqueous solutions of trichloroethylene (TCE) and chlorobenzene (CB) through the silicone rubber (polydimethylsiloxane, PDMS) membrane were carried out and the effect of concentration polarization on the separation characteristics was investigated. The resistance-in-series model was used to explain the boundary layer resistance. It was clear that the concentration polarization phenomenon had a significant effect on the permeation behavior in the pervaporation separation of the trace organic chlorides from aqueous solutions. With the same membrane thickness, the permeation of TCE, which has a stronger affinity for the PDMS, appeared to be more influenced by the boundary layer resistance than that of CB. The effect of boundary layer resistance was reduced and the membrane resistance became dominant with increasing membrane thickness at a given hydrodynamic condition. The separation factor was increased to approach the intrinsic separation factor of the membrane with its thickness.

• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.3
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• pp.199-211
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• 2013

Glasses industry has great growth potential from the future-oriented perspective in Korea. In consideration of the fact that the ratio of aging population increases in this aging society, people have more and more interest in health. Also, their recognition on the cycle to change glasses is changing, and the utility of them as fashion items is increasing day by day, it is expected that the demand for glasses will be even more extended afterwards. Of course, presently it suffers from the gap between cheaper items and expensive ones provided by overseas prominent brands due to the bi-polarization of the market. However, they are pursuing the 2nd growth as export-leading items in the past through international glass exhibitions based on knowhow accumulated for a long time. Therefore, this study aims to examine the current status of glasses design industry in Korea reflecting the actual situations we have now and also understand the problems and limitations internalized in our glass design industry through the research process. As a result, the study has drawn the following conclusions. This paper intends to point out first, the phenomenon of bi-polarization of the glass market in Korea. Second, unequal distribution by region centering around Daegu. Third, the limitations of brand identity. Fourth, the limitations of information, planning, and marketing power. Fifth, passive conduction of international events and their insufficient effects. This study concludes that all these problems can be solved through 'planning and design, and marketing power'.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.2
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• pp.301-306
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• 2013

The Ratio of APT jeonse to purchase price was still rising. The interaction of APT Purchase and Jeonse price indices by region analysis in order to analyze this phenomenon, and results were summarized as follows. First, because the regional APT purchase and jeonse prices appears the rise and fall differently by region, regional polarization was deepening. Second, the recently real estate market was analyzed the province's booming real estate and the downturn of the metropolitan area. So, the ratio of APT jeonse to purchase price was continued to rise. Finally, the Ratio of APT jeonse to purchase price changing rate is (+) increased if the APT purchase price changing rate is larger then the APT purchase price changing rate and smaller then is (-) decreased.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.383-389
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• 2003

Clay minerals show a distinct induced-polarization phenomenon, which is one of the most important factors for predicting groundwater flow and contaminant transport. This paper presents a step-by-step process to estimate Cole-Cole parameters from spectral induced-polarization (IP) data measured on the surface of three-dimensional earth. First, the inversion of low-frequency resistivity survey data is made to identify the dc resistivity ${\rho}_dc$ of a volume having IP effects. The other parameters, chargeability m, time constant $\tau$, and frequency dependence c, are sought for the polarizable volume. Next, using multi-frequency data, c can be obtained as high or low asymptotes of the slope of log phase vs. log frequency. Further, for low m, intrinsic $\tau$ is approximated by apparent one, ${\tau}_a$, which is derived from the relation ${{\omega}{\tau}}_a$=1 at an angular frequency $\omega$, where the imaginary component of spectral IP data has an extreme value. Finally, to obtain intrinsic m a two-step linearized procedure has been derived. For a body of given $\tau$ and c, forward modeling with a progression of m values yields a plot of observed vs. intrinsic imaginary components for a frequency. Since this plot is essentially linear, to extract the intrinsic imaginary component is quite simple with an observed value. Using the plot of intrinsic imaginary component vs. m, intrinsic m is determined. We present a synthetic example to illustrate that the Cole-Cole parameters can be recovered from spectral IP data.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1219-1220
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• 2015

마이크로, 나노유체 (micro-, nanofluidics)을 이용한 종이 기반 분석 소자 (paper-based analytical devices, micro-PADs)에 대한 관심이 증가하고 있다. 종이 기반의 분석 소자는 초저가의 비용과 간단한 공정 방법으로 인하여 상용화 컨셉의 바이오센서로 각광받고 있다. 하지만, 종이 기반의 분석 소자는 낮은 검출 한계 (limit of detection, LOD)와 민감도 (sensitivity)의 제한이 있다. 그로 인해 우리는 이온 선택적 투과층 (ion permselective membrane, i.e. Nafion)을 종이 기반의 분석 소자와 결합하여 이온 농도 분극 (ion concentration polarization, ICP) 현상을 구현하여 낮은 검출한계와 민감도를 개선할 수 있었다. 접착력이 있는 테이프 표면에 이온 선택적 투과층을 패터닝 (patterning)하여 종이 기반 분석 소자와 결합하여 매우 간단하게 소자를 제작할 수 있었다. 따라서 종이 기반의 채널 양단에 직류 전압을 인가했을 때 발생하는 ICP 현상으로 인하여 형광 물질 (fluorescence dye)이 농축(preconcentration)되는 것을 확인할 수 있었다. 구체적으로, 초기 농도가 1.55 nM인 형광 물질을 이용하여 200 V의 외부전압을 인가했을 때, 500 초 이내에 1000 배 이상의 농축비를 얻을 수 있었다. 따라서, 외부 전압을 상용화된 건전지 출력값으로 낮출 수 있다면 다양한 종이 기반 분석 소자와 간단한 결합 방법을 통해 상용화 컨셉의 바이오센서로도 구현이 가능할 것이다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.4
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• pp.291-297
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• 2003

Al-brass is usually used as the tube material of vessel's heat exchanger for seawater cooling system because it has high thermal conductivity and good mechanical properties and high corrosion resistance due to cuprous oxide (Cu20) layer against seawater. However, Al-brass tubes of heat exchanger for vessel at the actual environment is reported that local corrosion such as stress corrosion cracking occurred by synergism effect between mechanical factor and corrosion environment In this paper, the effect of corrosion environment on the stress corrosion cracking of Al-brass in various NH4OH of 3.5% NaCl solution, under flow by constant displacement tester. Based on the test results, the behavior of polarization, stress corrosion crack propagation and dezincification phenomenon of Al-brass are investigated. The main results are as follows：(1) Increasing range of potential from open circuit potential to repassivation gets lower, as the contain rate of NH4OH gets higher. (2) As contain rate of NH4OH gets higher, SCC of Al-brass is become activation but the protection film(Cu20) of Al-brass is created in 3.5% NaCl solution. (3) According as content of NH4OH increases in 3.5% NaCl solution, the dezincifiction area is spread. It is concluded that dezincification occurred by localized preferential anodic dissolution at stress focusing region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.269-273
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• 2001

W fabricated thin film using Na$_{0.5}$K$_{0.5}$NbO$_3$ volatile material by pulsed laser deposition (PLD) and studied characterization from EM, XRD, P-E. The density and scale of droplet, which is the defect of PLD, was investigated by SEM but large droplet was not found. The degree of assemble oriented C-axis measured with X-ray diffraction suggests that this film oriented C-axis achieved by $\theta$-2$\theta$ scan and rocking curves shows good self-assemble phenomenon, finally $\phi$-scan does that all of the four directions of the lattice in film equals to those of substrate. P-E hysteresis loop shows residual remnant polarization or saturation polarization value, but it is applicable to memories.ies.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.308-314
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• 2015

The electrochemical performance and Cr poisoning behavior of $La_{1-x}Ba_xCo_{0.9}Fe_{0.1}O_{3-{\delta}}$ (LBCF, x = 0.3, 0.4, 0.5) and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathodes were investigated for solid oxide fuel cells (SOFCs). The polarization resistance of the LBCF/GDC/LBCF symmetrical cell was found to decrease with increasing Ba content (x value). This phenomenon might be associated with the high oxygen vacancy concentration in the LBCF sample, with x = 0.5. In addition, there was no chromium poisoning in the LBCF cathode. On the other hand, the polarization resistance of the LSCF cathode was found to significantly increase after exposure to gaseous chromium species; it appears that this result stemmed from the formation of $SrCrO_4$ phase. Therefore, it can be expected that LBCF can be a durable potential cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFC).

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4474-4480
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• 2022

Deep geological disposal using a multibarrier system is a promising solution for treating high-level radioactive (HLRW) waste. The HLRW canister represents the first barrier for the migration of radionuclides into the biosphere, therefore, the corrosion behavior of canister materials is of significance. In this study, the electrochemical behaviors of SS316L, Ti-Gr.2, Alloy 22, and Cu in naturally aerated KAERI underground research tunnel (KURT) groundwater solutions were examined. The corrosion potential, current, and impedance spectra of the test materials were recorded using electrochemical methods. According to polarization and impedance measurements, Cu exhibits relatively higher corrosion rates and a lower corrosion resistance ability than those exhibited by the other materials in the given groundwater condition. In the anodic dissolution tests, SS316L exposed to the groundwater solution exhibited the most uniform corrosion, as indicated by its surface roughness. This phenomenon could be attributed to the extremely low concentration of chloride ions in KURT groundwater.