• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.130-132
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• 1994

We fabricated Ag ion exchange glass waveguide. Generally, ion-exchange glass waveguide. are suitable for passive integrated optical components such as directional and star couplers. Its advantages include low loss, ease of fabrication, and low material cost. So, we faricated Ag ion-exchange glass waveguides in AgNO$_3$ melt solution from 2 mole %. And we used Sodalime glass as a substrate in the fabrication process. As the results, we observed multivalent ion-exchange in a typical sodalime glass. Diffusion coefficient and depth are predicted by actual experimental data of Stewart. The exchange rate in silver-ion-exchanged waveguides are compared to the exchange time of waveguide fabrication.

• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.19-31
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• 2022

Lithium-ion battery development is one of the most active contemporary research areas, gaining more attention in recent times, following the increasing importance of energy storage technology. The galvanostatic intermittent titration technique (GITT) has become a crucial method among various electrochemical analyses for battery research. During one titration step in GITT, which consists of a constant current pulse followed by a relaxation period, transient and steady-state voltage changes were measured. It draws both thermodynamic and kinetic parameters. The diffusion coefficients of the lithium ion, open-circuit voltages, and overpotentials at various states of charge can be deduced by a series of titration steps. This mini-review details the theoretical and practical aspects of GITT analysis, from the measurement method to the derivation of the diffusivity equation for research cases according to the specific experimental purpose. This will shed light on a better understanding of electrochemical reactions and provide insight into the methods for improving lithium-ion battery performance.

• ETRI Journal
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• 제11권4호
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• pp.84-97
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• 1989

The influence of Zn, Si and Te diffusion on the interdiffusion in $GaAs-Ga_1_-xIN_xAs_1__yP_y$and InP$Ga_1__xIn_xAs_1__yP_y$ heterostructures was studied. The heterostructures were grown by liquid phase epitaxy, and the impurity diffusion into the heterostructures was carried out using metal compound or element sources. The extent of interdiffusion for both group III and V atoms was observed by depth profiling of matrix elements with secondary ion mass spectrometry and Auger electron spectroscopy. Selective enhancement of cation interdiffusion was observed by the concurrent Zn diffusion in both the GaAs based-and InP based-crystals. In contrast to the Zn diffusion, the Si diffusion in the GaAs based-crystal and the Te diffusion in the InP based-crystal enhanced both cation and anion interdiffusion to the same extent. A kick-out mechanism is proposed to explain the selective enhancement of the cation interdiffusion due to Zn, and a single vacancy mechanism is proposed for the interdiffusion due to Si and Te.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.289.1-289.1
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• 2016

Germanium (Ge) with higher carrier mobility and a lower crystallization temperature has been considered as the channel material of thin-film transistors for display applications. Various methods were studied for crystallizaion of poly-Ge from amorphous Ge at low temperature. Especially Metal induced crystalliazation (MIC) process was widely studied because low process cost. In this paper, we investigate copper diffusion process of different thick (70 nm, 350 nm) poly-Ge film obtained by MIC process at various temperatures (250, 300, and $350^{\circ}C$) through atomic force microscopy (AFM), Raman spectroscopy, and secondary ion mass spectroscopy (SIMS) measurement. Crystallization completeness and grain size was similar in all the conditions. Copper diffusion profile of 370 nm poly-Ge film show simirly results regardless of process temperature. However, copper diffusion profile of 70 nm poly-Ge film show different results by process temperature.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.181-186
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• 1994

The steel in concrete structures under the environment of seawater easily corrode as the seawater penetrate into concrete. The purpose of this study is to analysis the properties of chloride diffusion in mortar using mineral admixtures, as a part of study to examine the chloride penetration of concrete. The results show that the chloride diffusion in mortar increased with higher water-cement ratio. In the case of mortar using mineral admixtures the scope of diffusion coefficient$(\times10^{-8}cm^2/sec)$increased SF20(0.9), SG60(3.3), FA20(3.9), and OC(6.1) in order at the same water-cement ratio 50%.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.2039-2044
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• 2011

A semi-continuous and automated method for quantifying atmospheric ammonia at the parts per billion level has been developed. The instrument consists of a high efficiency diffusion scrubber, an electrolytic on-line anion exchange device, and a conductivity detector. Water soluble gases in sampled air diffuse through the porous membrane and are absorbed in an absorbing solution. Interferences are eliminated by using an anion exchange devises. The electrical conductivity of the solution is measured without chromatographic separation. The collection efficiency was over 99%. Over the 0-200 ppbv concentration range, the calibration was linear with $r^2$ = 0.99. The lower limit of detection was 0.09 ppbv. A parallel analysis of Seoul air over several days using this method and a diffusion scrubber coupled to an ion chromatography system showed acceptable agreement, $r^2$ = 0.940 (n = 686). This method can be applied for ambient air monitoring of ammonia.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.372-375
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• 2006

SOFC is a high temperature fuelcell with many advantages, but it also have several demerits. One of the Issues is cathode poisoning of Cr coming from stainless steel interconnects. Diffusion process of Cr evaporated from the surface of interconnect steel was calculated by using CFD technique to understand factors for Cr deposition. It has been cleared that factors concerned in Cr deposition and how they affect Cr deposition. Major variables for Cr deposit ion are diffusion coefficient, air velocity and temperature If diffusion coefficient decreases, Cr concentration increases in the air but decreases on the cathode surface. Increasing in air velocity, Cr concentration decreases in the air and on the cathode surface. Increase in temperature leads to rising Cr concentration on the cathode surface because of diffusion coefficient increment.

• 반도체디스플레이기술학회지
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• 제4권1호
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• pp.23-27
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• 2005

This paper presents a simulation methodology for the poly-silicon oriented TCAD(technology-CAD) system. A computer simulation environment for the poly-silicon processing has been set up with the proper adoption of the two-stream model for ion-doping, diffusion, and defects inside of grain and on the grain boundary. After the simulator calibration, simulation results for the poly-silicon diffusion hat shown a good agreement with the SIMS data.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.281-284
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• 2003

When concrete structures are exposed under marine condition for a long time, the steel in concrete is corroded due to the ingression of chlorides in the sea water. Because the damages of corrosion resulting from the chloride ion are very serious, many research have been performed. In this study, it was experimentally investigated that the mechanical and diffusion characteristics of concrete substituted with ordinary portland cement, silica fume and blast furnace slag to investigate the chloride ingress characteristics with concrete quality. Chloride diffusion coefficients in concrete shows increasing tendency as w/c ratio increase. Also test results indicate that blend of admixture become lower chloride diffusion coefficients in concrete as compared with normal concrete.

• 한국산학기술학회논문지
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• 제5권3호
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• pp.210-217
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• 2004

본 연구는 기존 반도체 단위공정의 실리콘 중심 CAD 환경을 다결정실리콘 중심의 환경으로 전환하는 방법론에 대해 제안하였다. 다결정실리콘 공정에서의 확산과 이온도핑에 의한 불순물 이동에 관련하여 결정립내부와 결정립계상에서의 확산을 동시에 고려하는 이중흐름(two-stream)모델을 채택하고, 이와 관련된 파라미터들의 민감도 분석을 통하여 다결정실리콘 컴퓨터 시뮬레이션 환경을 재구성하였다. 시뮬레이터의 캘리브레이션 과정을 거친 결과 다결정실리콘에 대한 SIMS 데이터와 전반적으로 잘 일치하였다.