• Polymer(Korea)
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• v.35 no.2
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• pp.141-145
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• 2011

The electron beam (EB) induced curing of a typical resin designed for the hard coating layer of in-mold decoration foils was investigated. The samples were irradiated with different doses of EB and the curing reaction was monitored by Fourier transform infrared (FTIR) spectroscopy. The change in coating properties such as surface hardness and anti-abrasion property was studied as a function of increasing dose. The effect of the addition of nano-particles on the improvement of coating properties was also examined. It was expected that the experimental results could be used for the commercial exploitation of the EB curing system comparable to the ultraviolet (UV) curing system.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.145-151
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• 2008

Material degradation such as high temperature oxidation of metallic material is a severe problem in energy generation systems or manufacturing industries. The metallic materials are oxidized to form oxide films in high temperature environments. The oxide films act as diffusion barriers of oxygen and metal ions and thereafter decrease oxidation rates of metals. The metal oxidation is, however, accelerated by mechanical fracture and spalling of the oxide films caused by thermal stresses by repetition of temperature change, vibration and by the impact of solid particles. It is therefore very important to investigate mechanical properties and adhesion of oxide films in high temperature environments, as well as the properties in a room temperature environment. The oxidation tests were conducted for Ni and Ni-Co alloy under high temperature corrosive environments. The hardness distributions against the indentation depth from the top surface were examined at room temperature. Dynamic indentation tests were performed on Ni oxide films formed on Ni surfaces at room and high temperature to observe fractures or cracks generated around impact craters. As a result, it was found that the mechanical property as hardness of the oxide films were different between Ni and Ni-Co alloy, and between room and high temperatures, and that the adhesion of Ni oxide films was relatively stronger than that of Co oxide films.

• Corrosion Science and Technology
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• v.10 no.4
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• pp.118-124
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• 2011

Alloy 600 (Ni 75 wt%, Cr 15 wt%, Fe 10 wt%) as a heat exchanger tube of the steam generator (SG) in nuclear power plants (NPP) has been degraded by various corrosion mechanism during the long-term operation. Especially lead (Pb) is known to be one of the most deleterious species in the secondary system causing outer diameter stress corrosion cracking (ODSCC). Oxide formation and breakdown is requisite for SCC initiation and propagation. Therefore it is expected that a property change of the oxide formed on SG tubing materials by lead addition into a solution is closely related to PbSCC. In the present work, the SCC susceptibility was assessed by using a slow strain rate test (SSRT) in caustic solutions with and without lead for Alloy 600 and Alloy 690 (Ni 60 wt%, Cr 30 wt%, Fe 10 wt%) used as an alternative of Alloy 600 because of outstanding superiority to SCC. The results were discussed in view of the oxide property formed on Alloy 600 and Alloy 690. The oxides formed on Alloy 600 and Alloy 690 in aqueous solutions with and without lead were examined by using a transmission electron microscopy (TEM), equipped with an energy dispersive x-ray spectroscopy (EDXS).

• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.39-43
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• 2014

The effect of electrode charging on the ion energy distribution (IED) was investigated in the dual-frequency capacitively coupled plasma source which was powered of 100 MHz RF at the top electrode and 400 kHz bias on the bottom electrode. The charging property was analyzed with the distortion of the measured current and voltage waveforms. The capacitance and the resistance of electrode sheath can change the property of ion and electron charging on the electrode so it is sensitive to the plasma density which is controlled by the main power. The ion energy distribution was estimated by equivalent circuit model, being compared with the measured distribution obtained from the ion energy analyzer. Results show that the low frequency bias power changes effectively the low energy population of ion in the energy distribution.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.217-223
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• 2003

The present work is concerned with characterization of surface roughness and inhomogeneity of four kinds of hot-rolled carbon steels in terms of the fractal dimension and the depression parameter by using image analysis method and electrochemical impedance spectroscopy, respectively. From the analysis of the 3D AFM image, it is realized that all the hot-rolled steel surfaces show the self-affine fractal property. The values of the fractal dimension of the hot-rolled steels were determined by the analyses of the AFM images on the basis of both the perimeter-area method and the triangulation method. In addition, the Nyquist plots were found to be depressed from a perfect semicircle form. From the experimental findings, the changes in the values of the fractal dimension and the depression parameter with chemical composition have been discussed in terms of the change in the value of hardness of base steel.

• Transactions on Electrical and Electronic Materials
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• v.9 no.2
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• pp.52-56
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• 2008

Carbon nanotube films were fabricated by the catalytic CVD method. Plasma processed time effects on the field emission property were studied. The atomic structure was observed by using X-ray photoelectron spectroscopy (XPS). The surface composition changes were observed on the plasma processed CNT films. The O1s/C1s signal ratio and the Fls/Cls signal ratio changed from 1.1 % to 24.65 % and from 0 % to 3.1 % with plasma process time, respectively. We could guess it from these results that the Ar plasma process could change the surface composition effectively. In the case of the original-CNT film, no carbon shift was observed. In the case of the Ar plasma processed CNT films, however the oxygen related carbon shifts were observed. This oxygen related carbon shift at higher binding energy implies the increment of amount of the oxygen. It's possible that the increment of these bonds between carbon and oxygen results in the improvement of field emission performance.

• Korean Institute of Interior Design Journal
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• v.21 no.6
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• pp.62-70
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• 2012

This study investigated modern architectures adjacent to the road, which can be easily destroyed by economic logic. The purpose of this paper is to find the method to preserve and reuse as townscape. The research methods were used the literature survey and field research of modern architecture in Seoul, and compared with the current status. The result are as followings. Firstly, In order to preserve many architectural cultural properties, the policy related to cultural property should be improved. And, awareness of the individual about cultural property should be changed. Secondly, it has been analyzed that modern architecture can be divided into 3 types in the reuse, which is 'Succession Type', 'Change Type', and 'Extinction Type'. Most of the cases has been used for specific use. Therefore, we should be consider the method of the reuse which can accommodate the various contemporary use. Thirdly, the preservation of the appearance and facade, which is the optimal way to preserve at least the historicity of the city, would be suitable for the preservation of modern architecture adjacent to the road. Lastly, it has been analyzed that the cases can be divided into 2 types in the form of appearance, which is 'Modern Type' and 'Hanok Type'. And, common and individual design guidelines have made.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.18-22
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• 2017

Addition of $BaSnO_3$ (BSO) to $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to $750^{\circ}C$ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

• Korean Journal of Materials Research
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• v.12 no.9
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• pp.735-739
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• 2002

$(Y,Gd)BO_3$: Eu, $Zn_2$$SiO_4$ : Mn and $BaMgAl_{10}$ $O_{17}$ : Eu phosphors used in PDP were continuously irradiated by vacuum ultra violet generated from the penning gas (96%Ar+4%Xe) discharge and then the change of emitting intensity with time was investigated. The brightness of these phosphors decreased exponentially with VUV excitation time. The experimental data showed that the degradation rate increased in the order of $Zn_2$$SiO_4$ : Mn>(Y,Gd)$BO_3$: Eu>$BaMgAl_{10}$ $O_{17}$ : Eu phosphor. This different degradation property of phosphors was interpreted in terms of brightness saturation and stability against VUV irradiation. It was found that the degradation property of $(Y,Gd)BO_3$ : Eu red phosphor synthesized by ultrasonic thermal spray was superior to commercial phosphor.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.5
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• pp.14-20
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• 1997

This paper proposes a new design method for the SMC-type FLC and shows that a SMC-type LFC is an extension of the SMC with BL. The conventional SMC-type FLC uses error and change-of-error as inputs of the FLC and generates the absolute value of a switching magnitude. Then, the fuzzy rule table is constructed on a two-dimensional space of the phase plane and has commonly the skew symmetric property. In this paper, we introduce a new variable, signed distance, from the skew symmetric property of the rule table. And thd variable becomes only a fuzzy variable that is used to generate the control input of a SMC-type FLC. that is, we design a new SMC-type FLC that uses a signed distance and a control input as the variables representing the contents of the rule-antecedent and the rule-con-sequent, respectively. Then the number of total rules is reduced and the control performance is almost the same as that of the conventional SMC-type FLC. Additionally, we derive the control law of the ordinary SMC with BL from a new SMC-type FLC. Namely, we show that a FLC is an extension of the SMC with BL.