• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.03a
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• pp.165-171
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• 1996

Recently, to improve the productivity in the continuous casting process, thin slab continuous caster which is one of the new steelmaking technologies by a high speed casting has been introduced. In the process of the thin slab continuous cast, there is more possibility than convnetional one that the deformation be occurred by the bulging of solidified shell, since the thickness of soliidfied shell is very thin as much as 60mm after the casting is finished. In some cases of severe bulging, there might be more breakout. In this paper, using finite difference method , solification analysis of slab is made as well as the thicknessof solidified shell and temperature are calculated. Also, based on the data of the calculated temperature, the deformed behavior of solidified narrow face is anlayzed with the MARC which is a package program for finite element analysis.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.77-81
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• 2011

It is a well-known clinical fact that contrast-enhanced magnetic resonance angiography exaggerates vertebral arterial ostial stenosis and sometimes shows pseudostenosis. Considering the clinical significance of a lesion in the posterior circulation ischemia, the importance of an accurate imaging diagnosis of ostial stenosis should not be underestimated. We were able to differentiate pseudo stenosis of the ostium from true stenosis using thin-slab maximum-intensity-projection(MIP) images which are thought to be helpful for minimizing standard full thickness MIP images.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.251-258
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• 1998

Behaviro of ZrO2-C mateial used for submerged entry nozzle in thin slab casting was investigated. De-gradation of the material has been found to result from breakup of zirconia aggregate refered to as "destabilization" Destabilization is almost completed during preheating procedure and shows an increasing tendency as the purity of zirconia aggregate decreases and as the content of metallic Si used in ZrO2-C aggregate during preheating. Such concentrated components make grain boundary wider but do not cause any additional destabilization of zirconiaf zirconia.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.271-271
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• 1999

A concentration change during grade transition operation in thin slab casting is investigated through computer simulation and the results are compared with experimental measurements. Fluid flow and mixing patterns in various tundish levers and flow rates were analysed by a three-dimensional mathematical model. Based on the contained results, a simple, efficient and accurate computational model is suggested to predict the concentration profile at the outlet of the tundish. Based on the model, mixing in and below the mold was analyzed considering electromagnetic braking force. The predicted concentration profiles show good agreements with the measured values. It is found that the lower vortices in the mold are suppressed by the electromagnetic field and a plug-like flow region develops, which decreases the intermixing of two different grades of steel and shortens the length of transition region.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.138-143
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• 1998

The continuous casting process has been adopted increasingly in recent years to save both energy and labor. It has experienced a rapid development in the production of semi-finished steel products, replacing the conventional route of ingot casting plus rolling. To achieve this good merit, however, more studies about a heat transfer mechanism between roll and slab are needed. So this paper shows the results of the deformation behavior of steel cast slabs, which are about the solidification and heat transfer. This study is used to prevent internal cracks of a slab in a bending and unbending zone. The value of moving strand shell bulging between two supporting rollers under ferrostatic pressure and slab-self weight has been computed in terms of creep and elastic-plasticity. The high strand distributions in solidified shell undergoes a series of bulging are calculated with boundary condition a very closed to continuous steel cast slabs productions.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.679-684
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• 2014

Enhanced analysis is performed to design a wedge projection system with a slab structure that increases the projected image size. The specification values of the system such as the length of the slab structure and the imaging region are calculated and investigated using an optical simulation tool. We also propose a split imaging region method to represent a large tiled scene using the thin wedge waveguide structure. Experiments are performed to verify the feasibility of the proposed method.

• Journal of Korean Association for Spatial Structures
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• v.15 no.2
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• pp.95-103
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• 2015

UHPC(Ultra High Performance Concrete) is used widely with its remarkable performance, such as strength, ductility and durability. Since the fibers in the UHPC can control the tensile crack, the punching shear capacity of UHPC is higher than that of the conventional concrete. In this paper, seven slabs with different thickness and fiber volume ratio were tested. The ultimate punching shear strength was increased with the fiber volume ratio up to 1%. The shear capacity of specimens with the fiber content 1% and 1.5% do not have big differences. The thicker slab has higher punching shear strength and lower deformation capacity. The critical sections of punching shear failure were similar regardless of the fiber volume ratio, but it were larger in thicker slab.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1650-1660
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• 2000

Continuous casting process has been adopted increasingly in recent years to save both energy and labor. It has experienced a rapid development in the production of semi-finished steel products, rep lacing the conventional route of ingot casting and rolling. In order to achieve this merit, however, more studies about the mechanism between roll and slab are needed. In this paper, a dynamic bulging in steel cast slabs was simulated by considering the solidification and heat transfer. This study is to prevent internal cracks of a slab in a bending and unbending zone. The value of moving strand shell bulging between two supporting rollers under the ferrostatic pressure and slab-self weight has been calculated in terms of creep and elasto-plasticity. The strain and strain rate distributions in solidified shell undergoing a series of bulging are calculated with working boundary conditions.

• Current Optics and Photonics
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• v.6 no.4
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• pp.375-380
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• 2022

We demonstrate two types of light field displays based on waveguide grating coupler arrays: a line beam type and a point source type. Ultra violet imprinting of an array of diffractive nanograting cells on the top surface of a 50-㎛-thin slab waveguide can deliver a line beam or a point beam to a multidirectional light field out of the waveguide slab. By controlling the grating vectors of the nanograting cells, the waveguide modes are externally coupled to specific viewing angles to create a multidirectional light field display. Nanograting cells with periods of 300 nm-518 nm and slanted angles of -8.5°~+8.5° are fabricated by two-beam interference lithography on a 40 mm × 40 mm slab waveguide for seven different viewpoints. It is expected that it will be possible to realize a very thin and flexible panel that shows multidirectional light field images through the waveguide-type diffraction display.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.485-492
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• 2000

In the rail facilities the rail track consists of rail tie fastening accessories and bed,. The rail track is largely divided into Ballast Bed Track(BBT) and Concrete Bed Track(CBT) according to the type of bed. In this thesis among Concrete Bed Track slab track which is used for the Japanese high speed railway is a target of this study. Dynamic analysis by using finite element method are performed. where moving rain load is periodic function. Then through parametric study some conclusions are obtained as follow. Cement Asphalt Mortar(CAM) affects contrary mechanical behavior to rail and slab greatly. Therefore change of CAM spring coefficient should be handled with care, For slab thickness thin slab is more profitable to reduction of vibration of rail than thick one but mechanical capacity of slab is deteriorated, Improved structural type is proposed then structural analysis is performed for this one. This type is effective to reduction of vibration of railway system.