• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.119-123
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• 2023

This study is normal orientation technology of slit coating equipment to improve the quality of curved displays. Currently, the demand for curved displays is increasing significantly due to advantages such as screen immersion or design in various industries. Accordingly, changes in the display coating process are essential. In the curved display coating process, unlike the existing flat coating process, the nozzle must be rotated along the curvature of the curved surface to spray the coating solution. The coating solution must be applied while maintaining a uniform thickness. If the thickness of the coating liquid applied to the target surface is non-uniform, the quality of the product may be degraded such as image quality deterioration and light spreading. This paper presents technology and experimental results for keeping the nozzle of slit coating equipment perpendicular to the curved surface and is expected to contribute to the quality improvement of curved displays.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.282-283
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• 2014

An active study on UHPC, which has been recently used in high-rise building and bridges, is in progress. However, research on adhesion strength of normal concrete and UHPC is required to be studied due to the lack of information. In this study, experimental research progress for adhesion strength (shear strength of adhesive surface) evaluation of Bi-compressive strength concretes (UHPC, Normal concrete) is proceeded. First, specimens using glue are produced and surface treatment methods of concrete bonded section are considered. Second, Direct Shear test is applied on concrete bonded section of UHPC (80~180MPa) and Normal Concrete (NC). As a result of this study, it is confirmed that bond strength is deteriorated as the difference of intensity ration of NC and UHPC increases.

• Tribology and Lubricants
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• v.11 no.5
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• pp.114-121
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• 1995

An ultrasonic technique using normal-incident compressional waves was used to evaluate the surface and subsurface damage in ceramics produced by Hertzian indentation. Damage was produced by a blunt indenter (tungsten carbide ball) in glass-ceramic, green glass and silicon nitride. The damage was classified into two types; (1) Hertzian cone crack, in green glass and fine grain silicon nitride, and (2) distributed subsurface micro fractures, without surface damage, produced in glass ceramic. The ultrasonic technique was successful in detecting cone craks. The measurement results with the Hertzian cone cracks indicated that cracks perpendicular to the surface could be detected by the normal-incident compressional waws. Also shown is the capability of normal-incident compressional waves in detection distributed micro-sized cracks size of subsurface microfractures.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.140-143
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• 1997

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminium bar to investigate the basic flow characteristics. Considering the bonding mechanism of bi-metal contact surface as cold pressure welding, the normal pressure and the contact surface expansion are selected as process parameters governing the bonding condition. The critical pressure required for the bonding at the interface is obtained by solving a "local extrusion" using a slip line meyhod. A viscoplastic finite element method is used to analyze the steady state extrusion process. The boundary profile of bi-metal rod is predicted by tracking a particle path adjacent to interface surface. The variations of contact surface area and the normal pressure along the interface profile are predicted and compared to those by experiments.

• Journal of the Korean Mathematical Society
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• v.43 no.6
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• pp.1339-1355
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• 2006

This paper develops in detail the differential geometry of ruled surfaces from two perspectives, and presents the underlying relations which unite them. Both scalar and dual curvature functions which define the shape of a ruled surface are derived. Explicit formulas are presented for the computation of these functions in both formulations of the differential geometry of ruled surfaces. Also presented is a detailed analysis of the ruled surface which characterizes the shape of a general ruled surface in the same way that osculating circle characterizes locally the shape of a non-null Lorentzian curve.

• Journal of Korean Physical Therapy Science
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• v.5 no.4
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• pp.817-830
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• 1998

The purpose of this study is to investigate the relationship between effects of TENS (Transcutaneous Electrical Nerve Stimulation) and IFC(Interferrential Current Therapy) to the change of body surface temperature. Cases are 22 normal persons and 22 patients with low back pain. Digital Infrared Thermal Imaging system was used for the detection of body surface temperature. 50Hz in frequency and 25-35mA in intensity were applied to TENS and IFC, 15 and 10 minutes on each. The results were follows ; 1. TENS and IFC has on effect of decreasing surface temperature, which would be from cardiovascular factors. (P<0.001) 2. The influence of IFC to the body surface temperature is greater than TENS, and it seems to be vasoconstriction of sympathetic activity. 3. There were no significant differences of body surface temperature between the two groups before and after electrical stimulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.701-708
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• 1997

A direct boundary element method(DBEM) is developed for thin bodies whose surfaces are rigid or compliant. Th eHelmholtz integral equation and its normal derivative integral equation are adopted simultaneously to calculate the pressure on both sides of the thin body, instead of the jump values across it, to account for the different surface conditions of each side. Unlike the usual assumption, the normal velocity is assumed to be discontinuous across the thin body. In this approach, only the neutral surface of the thin body has to be discontinuous across the thin body. In this approach, only the neural surface of the thin body has to be discretized. The method is validated by comparison with analytic and/or numerical results for acoustic scattering and radiation from several surface conditions of the thin body; the surfaces are rigid when stationary or vibrating, and part of the interior surface is lined with a sound-absorbing material.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.8
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• pp.361-364
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• 2005

In this paper, surface temperatures of ZnO arresters as a function of ambient temperatures and leakage currents were experimentally investigated. The variations of the leakage current was below 10 uA, which comes about $4.5\%$ of the normal leakage current. Temperature differences between the ambient and the surface of arresters were not shown until $150\%$ to the normal leakage current, and were remarkable over $200\%$. From the results, we deduced a couple of polynomials which enables the calculation of the leakage current by the measurement of surface temperature. Tests on used arresters have shown the same results as the experimental one. Also, we expect that an arrester diagnosis is possible by measuring the surface temperature of them after more studies on the effect of wind, moisture penetration, and arrester types.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.365-371
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• 2001

The effects of light exposure and light intensity on surface color of Hanwoo (Korean native cattle) beef and color stability of fresh normal and DFD (dark, firm, dry) muscles during 7 days at $4{\pm}1^{\circ}C$ under three display conditions (Dark, Light1000 and Light3000) were investigated. The $L^*$, $a^*$, $b^*$, $C^*$ values and R630-R580 were significantly (p<0.05) higher in normal beef than in DFD beef. The $a^*$, $b^*$, $c^*$ values and R630-R580 of normal beef increased during the first day of display except Light3000 group, then gradually decreased over time. The surfaces of Hanwoo beef accumulated more metmyoglobin in the light than in the dark. Also, the rate of decrease in redness during refrigerated storage was enhanced by light exposure and increase in light intensity. Discolorations were more rapid in DFD beef than normal beef. Increasing light intensity promoted not only discoloration but also lipid oxidation. Therefore storage in the dark is effective in retarding the formation of a brown color in Hanwoo beef.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2961-2965
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• 2012

Mesoporous carbons with tailored pore size were prepared by using sucrose as the carbon source and silicas as the templates. The silica templates were obtained from a hydroxypropyl-${\beta}$-cyclodextrin-silica hybrids using ammonium perchlorate oxidation at different temperatures to remove the organic matter. The structures and surface chemistry properties of these carbon materials were characterized by $N_2$ adsorption, TEM, SEM and FTIR measurements. The catalytic performances of these carbon materials were investigated through the reduction of nitroaromatic using hydrazine hydrate as the reducing agent. Compared with other carbon materials, such as active carbon, and carbon materials from the silica templates obtained by using calcination to remove the organic matter, these carbon materials exhibited much higher catalytic activity, no obvious deactivation was observed after recycling the catalyst four times. Higher surface area and pore volume, and the presence of abundant surface oxygen-containing functional groups, which originate from the special preparation process of carbon material, are likely responsible for the high catalytic property of these mesoporous carbon materials.