• Nuclear Engineering and Technology
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• 제29권2호
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• pp.175-180
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• 1997

It has been known that eater-side corrosion of fuel rods in nuclear reactor is accompanied with the metallic loss of wall thickness and hydrogen pickup in the fuel dadding tube. The fuel dad corrosion is one of the major factors to be controlled to maintain the fuel integrity during reactor operation. An oxide later thickness measuring device equipped with ECT probe system was developed by KAERI, and whose performance test was carried out in NDT(Non-destructive Test) hot-cell or PIE(Post Irradiation Examination) Facility. At first, the calibration/performance test was executed for the unirradiated standard specimen rod fabricated with several kinds of plastic thin films whose thickness ore predetermined, and the result of which showed a good precision within 10% of discrepancy. And then, hot test us peformed for the irradiated fuel rod selectively extracted from J44 fuel assembly discharged from Kori Unit-2. The data obtained with this device were compared with the metallographic result obtained from destructive examination in PIEF hot-cell on the same fuel rod to verify the validity of the measurement data.

• 한국분말재료학회지
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• 제18권1호
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• pp.73-77
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• 2011

$Y(OH)_3$ nanowires were synthesized by a hydrothermal reaction of metallic Y with aqueous solution of LiOH. The morphology and the size of the nanowires changed with varying the volume of the LiOH solution inside the autoclave. $Y(OH)_3$ nanowires transformed to $Y_2O_3$ by a subsequent heat-treatment without morphological change. By a proper control of hydrothermal reaction parameter and heat-treatment, the yield of pure $Y_2O_3$ nanowires up to 97% was attained.

• Journal of Welding and Joining
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• 제32권5호
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• pp.26-31
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• 2014

Conventional TIG(C-TIG) welding process guarantees higher quality weldment when compared with other processes. However, C-TIG with inherent low penetration shows disadvantages in productivity, especially for thick-walled structure. To overcome these handicaps, active-flux TIG(A-TIG) welding has been introduced and studied widely in a motivation to improve both quality and productivity. Present study made a focus on optimum combination of oxide components to enhance arc contraction and penetration. Results indicated that arc contraction inducing enhancement of penetration could be possible when composition of active fluxes was well matched with base metal.

• 한국표면공학회지
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• 제51권1호
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• pp.11-20
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• 2018

Hydrophobic and Superhydrophobic surfaces are promising technology for the surface finishing of metallic materials due to its water-repellency. Realization of highly water-repellent surface on aluminum and its alloys provides various functionalities for real application fields. In order to realize the hydrophobic/superhydrophobic surfaces on aluminum and its alloys, various technologies have been demonstrated. Especially, traditional anodic oxidation for aluminum has been widely employed for the morphological texturing of surfaces, which is essential to enhance the hydrophobic efficiency. De-wetting superhydrophobic surface on aluminum provides various exceptional properties, such as anti-corrosion, anti-/de-icing, anti-biofouling, drag reduction, self-cleaning and liquid separation. Nevertheless, the durability and stability of superhydrophobic surfaces still remain challenges for their actual applications in engineering systems and industry. In this review, the theoretical/experimental studies and current technical limitations on the hydrophobic and superhydrophobic surface using anodic oxidation of aluminum have been summarized.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.156-157
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• 2006

The preparation of composite powders for plasma spraying by an in-house designed mechanofusion process is investigated. Results show that dry particle coating depends on the chemical and mechanical properties of powders. In metal/oxide and metal/oxide/carbide powder mixtures, fine ceramic particles coat the surface of the metallic coarser particles. A nearly rounded shape of the final composite particles is induced by the mechanical energy input with no formation of new phases. However with the carbide/metal powdered system, only an intimate mixture of components is achieved. It is suggested that the coating mechanism is governed by agglomeration and rolling phenomena.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.284-285
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• 2006

The nano-sized Fe powders were prepared by plasma arc discharge process using pure Fe rod. The microstructure and the sintering behavior of the prepared nanopowders were evaluated. The prepared Fe nanopowders had nearly spherical shapes and consisted of metallic core and oxide shell structures. The higher volume shrinkage at low sintering temperature was observed due to the reduction of surface oxide. The nanopowders showed 6 times higher densification rate and more significant isotropic shrinkage behavior than those of micron sized Fe powders.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.74-76
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• 2004

It is the new promising method of obtaining the information about the state of a surface of a solid body, thin and multilayer structures. An idea of the method consists in reading and analyzing the relations U(t), dU/dt(t), dU/dt(U) on an electrical cell when anodizing an investigated object. By these relation it is possible to control the presence of impurities in the metal on the path of the anodization front, a structure and characteristics of the object being oxidized as well as of an oxide which is being formed during anodizing, the change in composition of the oxide layer, the thickness and composition of metallic and dielectric layers being a part of the layers boundaries.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.47-47
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• 2007

Indium oxide conducting films were dep9sited on Si(100) substrates at various temperatures by liquid delivery metal organic chemical vapor deposition using Indium (III) tris (2,2,6,6-tetramethyl-3.5-heptanedionato) $(dpm)_3$ precursors. The films deposited at $200{\sim}400^{\circ}C$ were grown with a (111) preferred orientation and exhibit an increase of grain size from 21 to 33nm with increasing deposition temperature. In the range of deposition temperature, there is no metallic indium phase in deposited films.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.317.2-317.2
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• 2013

Ultrathin oxide encapsulated metal-oxide hybrid nanocatalysts have been fabricated by a soft chemical and facile route. First, SiO2 nanoparticles of 25~30 nm size have been synthesized by modified Stobber's method followed by amine functionalization. Metal nanoparticles (Ru, Rh, Pt) capped with polymer/citrate have been deposited on functionalized SiO2 and finally an ultrathin layer of TiO2 coated on surface which prevents sintering and provides high thermal stability while maximizing the metal-oxide interface for higher catalytic activity. TEM studies confirmed that 2.5 nm sized metal nanoparticles are well dispersed and distributed throughout the surface of 25 nm SiO2 nanoparticles with a 3-4 nm TiO2 ultrathin layer. The metal nanoparticles are still well exposed to outer surface, being enabled for surface characterization and catalytic activity. Even after calcination at $600^{\circ}C$, the structure and morphology of hybrid nanocatalysts remain intact confirm the high thermal stability. XPS spectra of hybrid nanocatalyst suggest the metallic states as well as their corresponding oxide states. The catalytic activity has been evaluated for high temperature CO oxidation reaction as well as photocatalytic H2 generation under solar simulation. The design of hybrid structure, high thermal stability, and better exposure of metal active sites are the key parameters for the high catalytic activity. The maximization of metal-TiO2 interface interaction has the great role in photocatalytic H2 production.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.120-120
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• 2003

The metallic oxide nanomaterials including ZnO, Ga$_2$O$_3$, TiO$_2$, and SnO$_2$ have been synthesized by a number of methods including laser ablation, arc discharge, thermal annealing procedure, catalytic growth processes, and vapor transport. We have been interested in preparing the nanomaterials of Ga$_2$O$_3$, which is a wide band gap semiconductor (E$_{g}$ =4.9 eV) and used as insulating oxide layer for all gallium-based semiconductor. Ga$_2$O$_3$ is stable at high temperature and a transparent oxide, which has potential application in optoelectronic devices. The Ga$_2$O$_3$ nanoparticles and nanobelts were produced using GaN single crystals, which were grown by flux method inside SUS$^{TM}$ cell using a Na flux and exhibit plate-like morphologies with 4 ~ 5 mm in size. In these experiments, the conventional electric furnace was used. GaN single crystals were pulverized in form of powder for the growth of Ga$_2$O$_3$ nanomaterials. The structure, morphology and composition of the products were studied mainly by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM).).