• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.682-688
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• 2009

A periodic away of zinc oxide(ZnO) micro-rods as fabricated by using chemical bath deposition and photo-lithography. Vertically aligned ZnO micro-rods array was successfully grown by chemical bath deposition method on ZnO seed layer. The ZnO seed layer was deposited on glass and the patterning was made by standard photo-lithography technique. The selective growth of ZnO micro-rods as achieved with the masked ZnO seed layer. The fabricated ZnO micro rods were found to be single crystalline and have grown along hexagonal c-axis direction of (0002) which is same as the preferred growth orientation of ZnO seed layer.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.272-277
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• 2000

The heat transfer characteristics of confined turbulent slot jet impingement on the flat plate with square rods(turbulence promoter) have been experimentally investigated at different nozzle configuration. The effects of jet Reynolds number (Re=3900, 5800, 7800, 9700), dimensionless slot-to-plate distance(H/B=4, 6, 8) and clearance(c) between square rods and the plate were examined. Measurement of heat transfer rate were conducted using naphthalene sublimation technique. When square rods were inserted over the heat transfer surface, heat transfer rate was slightly increased in the wall jet region and the sharp-edged orifice nozzle was heigher than squared orifice nozzle.

• Transactions on Electrical and Electronic Materials
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• v.8 no.5
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• pp.191-195
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• 2007

We investigated photoluminescence characteristics of ZnO nano needle-like rods grown on a c-plane $AL_2O_3$ substrate by the hot wall epitaxy method. The nano-rods were vertically well aligned along the ZnO c-axis. The diameters of the ZnO nano-rods ranged from 20 nm to 30 nm and their lengths were between 600 and 700 nm. In the photoluminescence spectrum at 10 K, the exciton emission bound to the neutral donor dominated while defect related emission was weakly observed. With a further increase of temperature, the free exciton emission appeared and eventually became dominant at room temperature.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.759-765
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• 2000

A composite material consists of two or more different material layers. Copper clad aluminum composite materials are being used for economic and structural reasons. This study is concerned with experimental investigation in the direct extrusion of copper clad aluminum rods through conical dies. The suggestion are given for the proper extrudability of copper clad aluminum rods via hot direct extrusion. This paper presents the variation of flow state and hardness at a variable of extrusion ratio and semi-angle of die. By measuring after and before extrusion radius ratio of Cu sleeve and Al core, proportional flow state has been considered. And also by measuring hardness, through extrusion way, a variation of hardness has been considered.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.119-124
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• 2000

The heat transfer characteristics of confined turbulent slot jet impingement on the flat plate with square rods(turbulence promoter) have been experimentally investigated. The effects of jet Reynolds number (Re=3900, 5800, 7800, 9700), dimensionless slot-to-plate distance(H/B=4, 6, 8) clearance(c) between square rods and the plate, and the length(d) of a side of the square rod were examined. Measurement or heat transfer rate were conducted using naphthalene sublimation technique. When square rods were inserted over the heat transfer surface, heat transfer rate was slightly increased in the wall jet region.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.91-98
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• 2015

This paper has proposed a reinforcing method for damaged RC columns with SRF sheets and Aramid rods. In order to verify the effectiveness and performance, two original columns and two reinforced columns with SRF sheets and Aramid rods were developed and tested under lateral cyclic displacement and a constant axial load. The test showed that the improvement of energy dissipation capacity was increased in terms of strength and ductility. In addition, an analytical modeling of the standard specimens was proposed using Response-2000 and ZeusNL program. The results of analytical and experimental studies for two standard columns were compared in terms of loading-displacement curve and energy dissipation capacity based on the nonlinear static analysis.

• Applied Science and Convergence Technology
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• v.27 no.2
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• pp.38-41
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• 2018

We demonstrate the growth of a sheet-like ZnO membrane on ZnO nano rod layers. The growth process is composed of 3 steps of ZnO seed formation, ZnO nano rod growth and sheet-like ZnO membrane formation on those nano rods. To confirm the fundamental growth mechanism, the lattice structures of each step were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurement. Analysis of the relation between the texture coefficient and the surface shape of the ZnO membrane on the ZnO nano rods shows that the surface morphology of ZnO nano structures can be controlled using the temperature of the growing solution and the concentration of the chemical solution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.1
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• pp.73-81
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• 1989

The purpose of this study is augmentation of heat transfer without additional power in a rectangular impinging air jet. As a method of passive heat transfer augmentation in a two-dimensional air jet, heat transfer surface of flat plate with rods is used. This study, particularly in the wall jet rigeon, investigates the effect of the clearance between the flat plate and rod. Mechanism of heat transfer enhancement is investigated by measuring the local heat transfer coefficient. It is concluded that the superposition of the effects of flow accelerlation through the clearance between the flat plate and the rod, and reattachment of the flow was the cause of the excellent performance. The overall heat transfer rate of flat plate with rods is about 1.5 times larger than that of flat plate without rods.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.2
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• pp.182-189
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• 1989

The propose of this study is augmentation of heat transfer without additional external power in 2-dimensional impinging air jet. The passive heat transfer augmentation method tried in this experimental study is placement of rod bundles with the clearance, 2mm, in front of the heat transfer surface. The effects of pitch distance among rods and nozzle-to-target plate distance are investigated. The overall heat transfer rate of flat plate with rods reaches maximum at H/B=10 and P=40mm, and for H/B=2 and P=40mm the augmentation rate of heat transfer becomes maximum to a value which is about 1.57 times that of the flat plate without rods.

• Journal of the Korean Ceramic Society
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• v.56 no.3
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• pp.298-301
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• 2019

This paper details the synthesis of α-FeOOH (goethite) rods through the reaction of iron (III) nitrate with KOH as a strong base, and shape control of the particles for use as a yellow inorganic pigment. The crystal phase of the α-FeOOH crystal with OH content according to the addition of KOH and the change in morphology were investigated. The optical properties varied with the aspect ratios, and the yellowness increased with increasing aspect ratio. However, the enhanced chromaticity characteristics reversed beyond a certain critical aspect ratio. Thus, the relative optimal aspect ratio of the α-FeOOH rods as a vivid yellow inorganic pigment was derived. The morphology and coloration of the prepared rods were investigated in detail using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and CIE Lab color parameter measurements.