• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.120-122
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• 1997

In this paper, the viewing angle characteristics of amorphous (a) - twisted nematic (TN) - liquid crystal display (LCD) on poly(viny)cirmamate (PVC) alignment surfaces were investigated. It was found that the threshold voltage is increased with increasing the polymerization on PVC surfaces. We suggest that the threshold voltage is affected to the surface anchoring strength with increasing the polymerization of the alignment film. Also, we obtained that the viewing angle of a-TN-LCD is increased with increasing the polymerization on PVC surfaces. Finally, we considered that the viewing angle of a-TN-LCD on PVC surfaces is large compared to TN-LCD on rubbed polyimide (Pl) surface.

• Electrical & Electronic Materials
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• v.10 no.6
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• pp.576-580
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• 1997

In this paper, the viewing angle characteristics of amorphous (a) - twisted nematic (TN)-liquid crystal display (LCD) on poly(vinyl)cinnamate (PVC) surface with UV (ultraviolet) light irradiation were investigated. It was found that the threshold voltage increases with increasing the polymerization of PVC surfaces. We observed that the domain size of a-TN-LCD decreases with increasing the photo polymerization by increasing UV light irradiation time on PVC films. Also, we observed that the viewing angle of a-TN-LCD increased with increasing the photo polymerization on PVC surfaces. Finally, we consider that the viewing angle of a-TN-LCD on PVC surfaces is large compared to a-TN-LCD on polyimide (PI) surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.127-128
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1031-1032
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.769-770
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.765-766
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.767-768
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.50-53
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• 2003

Most companies use technologies such as stereolithography, selective laser sintering, and fused deposition modeling to make parts for such small consumer products as telephones, heads, and shoes. The largest part that the existing RP systems can make is only 600 mm in length. Because most RP systems build parts by depositing, solidifying, or sintering material point-by-point, making larger objects takes a long time. and in many cases, large objects won't fit the build size. A new effective thick-layered RP process. Transfer type Variable Lamination Manufacturing using expandable polystyrene foam (VLM-ST) has been developed with thick layers and sloped surfaces. In this paper, a scaledown model of F16 Fighter with the length of 800 mm is rapidly fabricated using the VLM-ST process. In order to build a CAD model of F16 larger than 600 mm in length, the approach in VLM-ST is to build larger parts in multiple sub-parts and then glue them together. The fabricated result shows that the VLM-ST process employing thick layers and sloped surfaces is adequate for creating the real-sized large objects in the diverse fields such as automobiles, electric home appliances, electronics. and etc.

• International Journal of Contents
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• v.4 no.2
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• pp.7-12
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• 2008

In this paper, we present a real-time physical simulation model of water surfaces with a novel method to represent the water mass flow in full three dimensions. In a physical simulation model, the state of the water surfaces is represented by a set of physical values, including height, velocity, and the gradient. The evolution of the velocity field in previous works is handled by a velocity solver based on the Navier-Stokes equations, which occurs as a result of the unevenness of the velocity propagation. In this paper, we integrate the principle of the mass conservation in a fluid of equilateral density to upgrade the height field from the unevenness, which in mathematical terms can be represented by the divergence operator. Thus the model generates waves induced by horizontal velocity, offering a simulation that puts forces added in all direction into account when calculating the values for height and velocity for the next frame. Other effects such as reflection off the boundaries, and interactions with floating objects are involved in our method. The implementation of our method demonstrates to run with fast speed scalable to real-time rates even for large simulation domains. Therefore, our model is appropriate for a real-time and large scale water surface simulation into which the animator wishes to visualize the global fluid flow as a main emphasis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.393-399
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• 2006

In this paper we applied a ray tracing method to estimate the scattering characteristics from large scale random rough surfaces. For the electromagnetic field evaluation, we have used the diffracted coefficient of the knife edge diffraction for the diffracted rays and Fresnel's reflection coefficients in connection with reflected rays. In addition, we examine to search for the traced rays using the imaging method which can be obtained all rays to arrived at receivers accurately and the diffracted field from rough surfaces is considered. Numerical examples have been carried out for the scattering characteristics of an ocean wave-like rough surface and delay spread characteristics of a building-like surface. In the present work we have demonstrated that the ray tracing method is effective to numerical analysis of a rough surface scattering.