• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.123-130
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• 2020

Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.417-425
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• 2018

The main aim of this paper is to investigate the bending of Euler-Bernouilli nano-beams made of bi-directional functionally graded materials (BDFGMs) using Eringen's non-local elasticity theory in the integral form with compare the differential form. To the best of the researchers' knowledge, in the literature, there is no study carried out into integral form of Eringen's non-local elasticity theory for bending analysis of BDFGM Euler-Bernoulli nano-beams with arbitrary functions. Material properties of nano-beam are assumed to change along the thickness and length directions according to arbitrary function. The approximate analytical solutions to the bending analysis of the BDFG nano-beam are derived by using the Rayleigh-Ritz method. The differential form of Eringen's non-local elasticity theory reveals with increasing size effect parameter, the flexibility of the nano-beam decreases, that this is unreasonable. This problem has been resolved in the integral form of the Eringen's model. For all boundary conditions, it is clearly seen that the integral form of Eringen's model predicts the softening effect of the non-local parameter as expected. Finally, the effects of changes of some important parameters such as material length scale, BDFG index on the values of deflection of nano-beam are studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.164-165
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• 2005

The dry etch characteristics of GaAs over both AlGaAs and InGaP in planar inductively coupled $BCl_3$-based plasmas(ICP) with additions of $SF_6$ or $CF_4$ were studied. The additions of flourine gases provided enhanced etch selectivities of GaAs/AlGaAs and GaAs/InGaP. The etch stop reaction involving formation of involatile $AlF_3$ and $InF_3$ (boiling points of etch products: $AlF_3\sim1300^{\circ}C$, $InF_3$ > $1200^{\circ}C$ at atmosphere) were found to be effective under high density inductively coupled plasma condition. Decrease of etch rates of all materials was probably due to strong increase of flourine atoms in the discharge, which blocked the surface of the material against chlorine neutral adsorption. The process parameters were ICP source power (0 - 500 W), RF chuck power (0 - 30 W) and variable gas composition. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.76-80
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• 2011

The ITO/Cabon Nano Tube (CNT) nano composites were deposited by nano cluster deposition (ITO) and arc discharge deposition (CNT) on glass substrates. The structural, optical and photovoltaic performance of ITO/CNT nano composites as a counter electrode of dye-sensitized solar-cells (DSSCs) such films were investigated. At low temperature below $250^{\circ}C$, the ITO films deposited on CNT. The ITO/CNT nano composit showed a good optical and electrical property for the counter electrode of DSSCs. When the as-prepared ITO/CNT nano composites are used for the counter electrodes, the photovoltaic parameters are $V_{OC}$ = 0.69 V, $J_{SC}$ = 5.69 mA/$cm^2$, FF = 0.32, and $\eta$ = 0.53 %. The ITO/CNT nano composites showed the possibility for the counter electrode applications of DSSCs.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.507-520
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• 2016

The effect of ZnO on cellulose acetate in the removal of benzophenone-3 (BP-3) was investigated. The benzophenone-3 (BP-3) which is an endocrine disrupting chemical (EDC) was completely removed (100%) from the drinking water using Cellulose Acetate (CA) and zinc oxide (ZnO) composite membranes. The membranes were prepared by DIPS method and the filtration experiments were conducted by dead end filtration unit. The macrostructure of the membrane were studied by ATR-IR and XRD Spectra's. Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) were used to study the micro properties of the membranes. The laboratory experiments such as water uptake study and pure water flux performed to confirm the increasing hydrophilicity. The enhancing hydrophilicity was confirmed with respect to higher the concentration of nanoparticles. Evaluation of BP-3 removal was carried in different experimental conditions, such as, different Trans membrane pressure and different concentration of feed. The membrane with low pressure showed better performance by rejecting 100% of BP-3. However, 1 ppm, 3 ppm and 6 ppm of feed solution was used and among them 3 ppm of feed solution gives 100% rejection. The ZnO nanoparticales enhances the performance of CA membrane by showing maximum rejection.

• Journal of Powder Materials
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• v.15 no.2
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• pp.114-118
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• 2008

Functional nanomaterial is expected to have improved capacities on various fields. Especially, metal nanoparticles dispersed in polymer matrix and metal nanofiber, one of the functional nanomaterials, are able to achieve improvement of property in the electric and other related fields. In this study, the fabrication of metal (Ag) nanoparticle dispersed nanofibers were attempted. The Ag nanoparticle dispersed polymer nanofiber and Ag nanofiber were fabricated by electrospinning method using electric force. First, PVP/$AgNO_3$ nanofibers were synthesized by electrospinning in $18{\sim}22kV$ voltage with the starting materials (Ag-nitrate) added polymer (PVP; poly (vinylpyrrolidone)). Then Ag nanoparticle dispersed polymer nanofibers were fabricated to reduce hydrogen reduction at $150^{\circ}C$ for 3hr. And Ag nanofibers were synthesized by the decomposited of PVP at $300{\sim}500^{\circ}C$ for 3hr. The nanofibers were analyzed by XRD, TGA, FE-SEM and TEM. The experimental results showed that the Ag nanofibers could be applied in many fields as an advanced material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.153-153
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• 2009

In the study the volume resistivity Characteristics of epoxy resin using nano and micro filler, nano and micro filler are made from insulating material epoxy resin using for transformer equipment and molding several devices as changing amount of addition of diameter 12 [nm] and 7 [${\mu}m$] $SiO_2$, we measured volume resistivity of nano and micro filler by High Resistance Meter(4329A). As the result of measurement, When is micro filler, the volume resistivity continuously increased over 80 [$^{\circ}$].

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.98-101
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• 2011

A 10 nm nano-silica was introduced to a conventional 3 ${\mu}M$ micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.

• Advances in materials Research
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• v.9 no.1
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• pp.33-48
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• 2020

With the use of differential quadrature method (DQM), forced vibrations and resonance frequency analysis of functionally graded (FG) nano-size beams rested on elastic substrate have been studied utilizing a shear deformation refined beam theory which contains shear deformations influence needless of any correction coefficient. The nano-size beam is exposed to uniformly-type dynamical loads having partial length. The two parameters elastic substrate is consist of linear springs as well as shear coefficient. Gradation of each material property for nano-size beam has been defined in the context of Mori-Tanaka scheme. Governing equations for embedded refined FG nano-size beams exposed to dynamical load have been achieved by utilizing Eringen's nonlocal differential law and Hamilton's rule. Derived equations have solved via DQM based on simply supported-simply supported edge condition. It will be shown that forced vibrations properties and resonance frequency of embedded FG nano-size beam are prominently affected by material gradation, nonlocal field, substrate coefficients and load factors.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.613-616
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• 2008

We report on electrical and optical properties of flexible ITO electrode grown on PET substrate using a specially designed roll-to-roll facing target sputtering (R2R FTS) system at room temperature without conventional cooling drum. Due to effective confinement of high density plasma between ITO targets, we can grow a flexible ITO electrode without cooling drum at room temperature.