• Polymer Science and Technology
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• v.3 no.4
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• pp.292-301
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• 1992

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.223-228
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• 1994

The strength development of polymer concrete using an unsaturated polyester polymer varies depending on many factors. However, the strength development is mostly dependent upon the age and curing temperature if the mixture ratios are the same. This study conducted to experimentally describe the relationship between the strength development and maturity which is defined as a function of $\Sigma$(time $\times$ temperature). The research result may be applied to predict the compressive, tensile and splitting strengths of the polymer concrete by computing the maturinty of the concrete.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1702-1703
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• 2011

MEMS 소자의 Wafer level Package 관련하여 Deep cavity를 가진 Cap Wafer와 Polymer bonding 중 cavity 단차로 인한 Polymer Patterning 및 접합 불량의 어려움을 극복할 수 있는 새로운 공정 flow를 제안하였다. Cavity를 형성할 때 사용하는 Si deep etching Mask인 기존의 Photoresist를 접합용 감광성 Polymer로 대체하고, cavity 형성 후, 별도의 추가 공정 없이 이 Polymer를 이용해 Wafer bonding을 진행하였다. 이를 통해 cavity 단차에 따른 문제를 해결함과 동시에 공정이 단순하고 제작 비용이 저렴하며, 신뢰성 있는 Wafer level Package를 구현하였다.

• Polymer Science and Technology
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• v.2 no.4
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• pp.257-269
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• 1991

• Proceedings of the Korean Society of Rheology Conference
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• 2000.11a
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• pp.61-64
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• 2000

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.629-632
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• 2009

We have proposed a novel viewing angle controllable display of in-plane switching (IPS) mode with single panel. One pixel of this device is divided to two regions, in which main pixel shows image and sub pixel for viewing angle control. In initial state, the liquid crystal of sub pixel is homogeneous aligned on substrate for wide viewing angle mode. On the other hand, after applying voltage, the liquid crystal of sub pixel tilts up for narrow viewing angle mode. The proposed device has advantage for the function for simple manufacturing process and good viewing angle control with single panel.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.101-110
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• 2018

This study experimentally investigated the compressive and flexyral strength development characteristics of polymer concrete using four different type polymeric resins such as unsaturated polyester, vinyl ester, epoxy, and PMMA (polymethyl methacrylate) as binders. The test results show that the average compressive strength of those four different polymer concretes was 88.70 MPa, the average flexural strength was 20.30 MPa. Those test results show that compressive and flexural strengths of polymer concrete were much stronger than compressive and flexural strengths of ordinary Portland cement concrete. In addition, the relative gains of the compressive strength development at the age of 24 hrs compared to the age of 168 hrs were 68.6~88.3 %. Also, the relative gains of the flexural strength development at the age of 24 hrs compared to the age of 168 hrs were 73.8~93.4 %. These test results show that compressive and flexural strengths of each polymer concrete tested in this study were developed at the early age. Moreover, the prediction equations of compressive and flexural strength developments regarding the age were determined. The determined prediction equations could be applied to forecast the compressive and flexural strength developments of polymer concrete investigated in this study because those prediction equations have the high coefficients of correlation. Last, the relations between the compressive strength and the flexural strength of polymer concrete were determined and the flexural/compressive strength ratios were from 1/4 to 1/5. These results show that polymer concretes investigated in this study were appropriate as a flexural member of a concrete structure because the flexural/compressive strength ratios of polymer concrete were much higher than the flexural/compressive strength ratios of Portland cement concrete.

• Polymer Science and Technology
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• v.3 no.3
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• pp.185-206
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• 1992

• Polymer(Korea)
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• v.30 no.1
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• pp.50-55
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• 2006

When the monodisperse polystyrene(PS)/HDDA polymer particles were synthesized via one-step polymerization using polystyrene seed particles by dispersion polymerization, the effects of 1) the molecular weight of seed polymer particles, 2) the ratio of the absorbed HDDA to the seed polymer particles (swelling ratio) and 3) seeded polymerization rate on the surface morphology of PS/HDDA polymer particles were investigated. It was observed that the creation of the crater shaped defect on the surface of PS/HDDA polymer particles was irrespective of the molecular weight of seed polymer ant swelling ratio. But its surface morphology could be controlled by the change of the seeded polymerization rate.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.893-896
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• 2007

A series of new photosensitive polyimides having long alkoxy cinnamate chains were synthesized for liquid crystal (LC) photoalignment material. The polymer after irradiating linearly polarized UV light induced homogeneous and stable LC alignment. The chemical structure of the polymeric material was characterized and their photochemical LC alignment behavior was evaluated.