• Corrosion Science and Technology
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• v.11 no.1
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• pp.15-19
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• 2012

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

• Korean Journal of Metals and Materials
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• v.50 no.1
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• pp.8-12
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• 2012

This study aims to analyze the formability property of surface texturing processed automotive steel sheet for improving the sheet forming property. In the paper, the effect of cavities fabricated using the laser surface texturing technique on automotive high strength steel sheets was studied. The frictional behavior of the sheet drawing is a function of interface parameters such as sheet surface roughness, holding force, contact pressure, etc. For these reasons, automotive steel researchers want to optimize the surface topography of automotive steel sheets in order to enhance the formability. Therefore, this study presents the behavior of deformation of a laser surface texturing steel sheet by considering the frictional operation during the deep drawing process.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.940-944
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• 2003

With the increasing demand for plastic micro components, micro-/nano-molding using the mother stamper has received much attention. If the replication temperature is too high, the adhesion between the stamper and the polymer melt may deteriorate the surface quality of the replicated part, excessively wearing down the stamper. In this paper, an experimental method analyzes the temperature dependency of the anti-adhesion property between the actual stamper with patterns of sub-micrometer and the polymer melt. As a practical example, a correlation between the contact angle of the stamper and the surface quality of the molded substrates as a function of the replication temperature, respectively, was obtained quantitatively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.196-200
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• 2009

Lithium niobate ($LN:LiNbO_3$) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in surface acoustic wave (SAW). To manufacture LN devices, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult b traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters such as down force and relative velocity, were investigated for the LN CMP process To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1271-1278
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• 2000

A general curve and surface is a basic method to generate Free-form object using the fundamental properties of blending function. In typical method, there is an overhead of calculating to present Free-form object with the line segments and interpolation algorithm, In this paper, for resolving this problem efficiently, it will propose the flexible Free-form curves/surfaces using Ball curve shape-preserving property. This method includes Geometric Continuity that is needed to design Free-form Surface of high degree consisted with many curves. Also, when lots of data are reduced using Geometric Property of Free-form curves, the shape-preserving property of resulting object can be maintained, then it can represent any Free-form object with less calculating .

• Journal of the Korean Statistical Society
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• v.36 no.1
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• pp.157-173
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• 2007

In this article it is considered that how the slope-rotatability property of a second order design for response surface model is affected by block effects and how the design points are assigned into the blocks so that the blocked design may have the property of slope-rotatability. If an unblocked design is blocked properly, it could be a slope-rotatable design with block effects and this property is named as block slope-rotatability. We approach this problem from the moment matrix of the blocked design, which plays an important role to get the variances of the estimates, and suggest conditions of block slope-rotatability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.88-91
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• 2001

The mechanical properties and surface luminous intensities of copper foil have been studied with variation of the amount of additives into the electrolyte. Especially, organic compound of HEC was added from 0.1 to 10ppm for the propose of increasing the mechanical property and the surface state. The total thickness of electrodeposited copper foil was decreased with increasing the amount of organic compounds. There was not so much significant effect of the current density. It has been observed that mechanical property and surface luminous intensity increase with increasing concentration of organic compounds.

• Journal of the Korean Applied Science and Technology
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• v.19 no.2
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• pp.86-96
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• 2002

Oligomer type anionic surfactants(RmM-Na or RmD-Na} were synthesized from $C_{8}{\sim}C_{16}$ long chain alkylvinylether and maleic anhydride (or maleic diethylether). And also their fluorescent anionic surfactants (RmF- Na) were obtained from alkali neutralization which opens the lactone ring of the condensing materials produced by maleic anhydride alkylvinylether copolymer and 3-aminophenol. The measurement results for the surface active properties of water soluble oligomer type anionic surfactants with fluorescent structure (RmF-Na) exhibited a remarkable surface tension lowing property, foam breaking property, and a ernulsing power.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.2
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• pp.46-56
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• 2014

The aim of this reviews is to introduce the information concerning design of the UV-curable jet ink composition in order to provide a good adhesive property on non-porous surface. In order to clarify the viscosity dependence of flying speed for the UV curable jet ink, rheological analysis and observation of the flying state of the ink were carried out. The relationship between ink formulas and adhesive property on non-porous surface was investigated. It was examined the adhesive property of radical polymerization type UV curable jet ink included hydrogen abstraction type photo-initiator, it was expected that the strong adhesive strength can be obtained between the ink and non-porous surface in this study. UV curable jet ink with a slight amount of water was prepared. Optimum ratio of the cationic polymerization type UV curable jet ink shows an adequate adhesive strength towards two kinds of non-porous surface such as glass, poly(vinyl chloride) when tests were conducted on the ink jet-printing test machine.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.435-441
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• 2021

This research was performed to study the effect of the Ni + Mo addition on the fatigue properties in 12Cr steel. After heat treatment of 12Cr steel and 12Cr-Ni-Mo steel, tensile tests, impact tests, hardness tests, and rotary bending fatigue tests were performed, respectively. The fatigue fracture surface was observed and analyzed using SEM and EDS. The fatigue limit of 12Cr steel was 554 MPa, which was 49 MPa higher than 505 MPa of 12Cr-Ni-Mo steel. Striations, which are the shape of the typical fatigue fracture surface, were observed at the fracture surface near the starting point of fatigue fracture in the 12Cr steel and 12Cr-Ni-Mo steel. However, unlike the case of 12Cr steel, 12Cr-Ni-Mo steel also had a mixed fracture surface with the fatigue and the ductile fracture surface. When brittle non-metallic inclusions exist near the starting point of fatigue failure, the crack propagation was further promoted and the fatigue life was drastically reduced.