• Journal of Sensor Science and Technology
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• v.5 no.6
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• pp.60-67
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• 1996

The interfacial electrical properties of InSb MIS structure with low temperature remote PECVD $SiO_{2}$ have been characterized. The interlace-state density at mid-bandgap of the MIS structure was about $1{\sim}2{\times}10^{11}\;cm^{-2}eV^{-1}$, when the $SiO_{2}$ film was deposited at $105^{\circ}C$. However, large amount of interlace states and trap states were observed in the MIS structure fabricated at temperatures above $105^{\circ}C$. The time constant of $10^{-4}{\sim}10^{-5}\;sec$ of interface states was extracted from G- V measurement. As the deposition temperature increased, the hysteresis of C- V curves were increased due to the high trap density.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.3
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• pp.632-640
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• 1997

Changes in surface properties and detergency of sunactant mixtures were investigated in order to study the optimum mixing ratio of anionic and nonionic surfactants by measuring surface tension, interfacial tension, suspendability, and emulsification as a Amction of mixing ratio. Also, surface tension and detergency of the surfactant mixtures were determined with the increase of water-hardness or temperature. The results were as follows: the addition of NPE to anionic surfactant solutions (LAS or SDS) by 0.1 mole fraction remarkably decreased surface tension. NPE (n=15)/anionic surfactant mixtures showed a synergistic effect in lowering interfacial tension and emulsification, but NPE (n=7.5)/anionic surfactant mixtures did not. In suspension stability, however, synergism appeared when LAS or 505 was mixed with both of NPE's. With respect to the hydrophile of NPE, NPE (n=15) was more effective than NPE (n=i.5) in improving suspension stability. Detergency of LAS/NPE mixture changed almost linearly with mixing ratio, but that of SDS/NPE mixture increased remarkably by the addition of 0.1 or 0.2 mole fraction of NPE at all temperatures. As the temperature increased, surface tension of surfactant mixtures decreased and detergency was improved, but their synergistic effect decreased. In hard water, the mixtures showed better detergency than single surfactuant solutions.

• Membrane and Water Treatment
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• v.8 no.4
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• pp.323-336
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• 2017

The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute permeation was carried out under applied pressure of 5 bar at $25^{\circ}C$. Surface properties of TFC membrane were characterized by ATR-FTIR, SEM and AFM. The performance test indicated that 3.5 wt% of MPD, 0.35 wt% of TMC and curing temperature of $75^{\circ}C$ are the optimum conditions. Moreover, the permeate flux was $4.3{\frac{L}{m^2\;h}}$ and acetic acid rejection was about 43% at these conditions.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.710-714
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• 2007

LSGM$(La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2}O_{3-{\delta}})$ is the very promising electrolyte material for lower-temperature operation of SOFCs, especially when realized in anode-supported cells. But it is notorious for reacting with other cell components and resulting in the highly resistive reaction phases detrimental to cell performance. LDC$(La_{0.4}Ce_{0.6}O_{1.8})$, which is known to keep the interfacial stability between LSGM electrolyte and anode, was adopted in the anode-supported cell, and its effect on the interfacial reactivity and electrochemical performance of the cell was investigated. No severe interfacial reaction and corresponding resistive secondary phase was found in the cell with LDC buffer layer, and this is due to its ability to sustain the La chemical potential in LSGM. The cell exhibited the open circuit voltage of 0.64V, the maximum power density of 223 $mW/cm^2$, and the ohmic resistance of $0.17{\Omega}cm^2$ at $700^{\circ}C$. These values were much improved compared with those from the cell without any buffer layer, which implies that formation of the resistive reaction phases in LSGM and then deterioration of the cell performance is resulted mainly from the La diffusion from LSGM electrolyte to anode.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.384-388
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• 2013

Fluorine-doping on the $Li_{1+x}Mn_{1.9-x}Al_{0.1}O_4$ spinel cathode materials is found to alter crystal shape, and enhance initial interfacial reactivity and solid electrolyte interphase (SEI) formation, leading to improved initial coulombic efficiency in the voltage region of 3.3-4.3 V vs. Li/$Li^+$ in the room temperature electrolyte of 1 M $LiPF_6$/EC:EMC. SEM imaging reveals that the facetting on higher surface energy plane of (101) is additionally developed at the edges of an octahedron that is predominantly grown with the most thermodynamically stable (111) plane, which enhances interfacial reactivity. Fluorine-doping also increases the amount of interfacially reactive $Mn^{3+}$ on both bulk and surface for charge neutrality. Enhanced interfacial reactivity by fluorine-doping attributes instant formation of a stable SEI layer and improved initial cyclic efficiency. The data contribute to a basic understanding of the impacts of composition on material properties and cycling behavior of spinel-based cathode materials for lithium-ion batteries.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.35-39
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• 2018

This paper deals with the relaxation of singular stresses developed in an epoxy adhesive at high temperature. The interface stresses are analyzed using BEM. The adhesive employed in this study is an epoxy which can be cured at room temperature. The adhesive is assumed to be linearly viscoelastic. First, the distribution of the interface stresses developed in the adhesive layer under the uniform tensile stress has been calculated. The singular stress has been observed near the interface corner. Such singular stresses near the interface corner may cause epoxy layer separated from adherent. Second, the interfacial thermal stress has been investigated. The uniform temperature rise can relieve the stress level developed in the adhesive layer under the external loading, which can be viewed as an advantage of thermal loading. It is also obvious that temperature rise reduces the bonding strength of the adhesive layer. Experimental evaluation is required to assess a trade-off between the advantageous and deleterious effects of temperature.

• Korean Journal of Materials Research
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• v.15 no.10
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• pp.662-666
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• 2005

Solid solutions of $(Zr/Ti)O_2$ were prepared in powder form by the coprecipitation technique. After mixing with carbon or exposing to nitrogen gas at elevated temperature, titanium cations selectively diffused out from the oxide compound to form titanium carbide (TiC) or titanium nitride (TiN), respectively. TiN formed strong interfacial contacts between the oxide grains. In contrast, TiC formed as small crystallites on oxide grains but did not bind the matrix grains together. TiN therefore played a role in strengthening the interparticle bonding, but TiC weakened the bonding between grains. Partial diffusion of titanium cations also led to nanolayered structure being formed between the oxide grains, which provided weak interfacial layers that fractured in a step-wise fashion.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.99-105
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• 2002

A finite volume numerical approach is developed and used to simulate convection-dominated melting and solidification problems. The present approach is based on the enthalpy-porosity method that is traditionally used to track the motion of the liquid-solid front and to obtain the temperature and velocity profiles in the liquid-phase. The enthalpy-porosity model treats the solid-phase as the porosity in all computational cells that are located on the solid-liquid interfacial boundary. Concerning the computational cells that are fully located in the solid side of the interfacial boundary, the zero value of the porosity severely suppresses the velocity vector to practically a non-existent value that could be set equal to zero. A comparative analysis with the previous numerical approaches is performed to demonstrate the improved features of the presented model. Results of a melting and solidification experiments are also used to assess and evaluate the performance of the model.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.32-38
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• 1999

A biosurfactant produced by Tsukamurella sp. 26A was purified by procedures including acid precipitation, ethylacetate extraction, and adsorption chromatography. The purified biosurfactant reduced the surface tension of water from 72 mN/m to 30 mN/m at a concentration of 250 mg/l, whereas the minimum interfacial tension against n-hexadecane was lowered to 1.5 mN/m at a concentration of 40 mg/i. The compound stabilized oil-in-water emulsions with a variety of commercial oils and had strong emulsification and stabilization activities when compared to those of commercial emulsifiers and stabilizers. Surface tension was stable over a broad range of pH (2-12) and temperature ($100^{\circ}C$, 3h). The biosurfactant was identified as glycolipid having a hydrophilic moiety of trehalose.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.120-130
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• 1995

To analyze the mechanical property and the residual stress in functionally gradient materials(FGMs), disctype TZP/Ni-and TZP/SUS304-FGM were hot pressed using powder metallurgy compared with directly bonded materials which were fabricated by the same method. The continuous interface and the microstructure of FGMs were characterized by EPMA, WDS, optical microscope and SEM. By fractography, the fracture behavior of FGMs was mainly influenced by the defects which originated from the fabrication process. And the defectlike cracks in the FGMs induced by the residual stress have been shown to cause failure. This fact has well corresponded to the analysis of the residual stress distribution by Finite Element Method (FEM). The residual stress generated on the interface (between each layer, and matrix and second phase, respectively) were dominantly influenced on the sintering temperature and the material constants. As a consequence, the interfacial stability and the relaxation of residual stress could be obtained through compositional gradient.