• Transactions of Materials Processing
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• v.19 no.3
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• pp.185-190
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• 2010

Application of CAE analyses are wide spread in shaping processes and structural safety verification of plastic products. The importance of CAE analysis and its contributions are getting increase since the processibility and structural safety of product can be predicted. CAE analysis for complex shaped product need a lot of time for modeling and computation compare with simpler one. Therefore careful simulation modeling is required for complex shaped product. Structural analysis for plastic door handle of automobile has been performed and structural safety has been investigated for various load directions and modeling cases. Large stress occurred at the hinge in handle regardless of load direction and modeling case. Consequently hinge is considered structurally very weak among the parts in plastic door handle. It is concluded that simple modeling rather than total modeling with adequate boundary condition equivalent to real situation gives reasonable computational results with saving modeling effort and computation time.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1404-1409
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• 2007

Polymers for laser sintering were needed in order to fabricate the articles with the three-dimensional duplication equipment of SLS (selective laser sintering) process. The thermal properties, particle size, distribution, and shape of polymer powder had a close relation with the processibility of laser sintering. In this study, we prepared new polymer powders with uniform size and higher bulk density by wet process. Wet process consists of several finely-controlled steps such as dissolution, nucleation, propagation and crystallization. Several additives were added to improve the thermal, rheological, and flow properties.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.83-84
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• 2006

In aqueous phase, we directly prepared conducting and photoluminescent nano-structured particles by oxidation polymerization. Thiophene(PT) was initiated by $FeCl_{3}/H_{2}O_{2}$ (catalyst/oxidant) combination system. And, polydispersed core-shell poly(styrene/thiophene) and polyaniline(PANI)-coated multi core-shell polystyrene latex particles were successfully prepared by oxidative and radical polymerization. The resulting latex particles have fine improved luminescence and conductive efficiency and dispersion state due to the PT and PANI shell. Hyper functionalized nanoparticle would be expected to increase the processibility in various electrical and electro-optical fields.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.661-663
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• 2003

In this paper, production of TFT-LCD adopting Cu electrode, in spite of low resistivity, which was not commercially applied to TFT LCD products because of processibility, reliability problems etc. was mentioned. Based on the test result of etch and strip process of Cu electrode, the TFT device using Cu material shows the same characteristics as the conventional TFT devices. We describe the realization of a 20.1" UXGA model which was firstly applied to Cu electrode.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1057-1059
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• 2003

New polyfluorene derivatives, poly[9,9-bis(4' n-octyloxyphenyl)] fluorene (PAPF-8) and poly[9,9-bis(4'-(2",7"-dimethylocyloxy)phenyl)] fluorene (PAPF-10) were synthesized from the monomers, 2,7-dibromo-9,9-bis[4' (2"-ethylhexyloxy)benzene] fluorene and 2,7-dibromo-9,9-bis[4' (2", 7"-dimethyloctyloxybenzene)] fluorene through the Ni(0) mediated polymerization. The copolymers were characterized using FT-IR spectroscopy, UV-vis spectroscopy, TGA, photoluminescence (PL) & electroluminescence (EL) spectroscopy, elementa analysis, and molecular weight studies. The synthesized POPF-8 and POPF-10 showed a pure blue emission without any spectral change upon thermal annealing and EL device operation.

• Korea-Australia Rheology Journal
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• v.16 no.4
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• pp.213-218
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• 2004

Linear high-density polyethylene (PE) was controlled to induce strain-hardening behavior by introducing a small amount of second component with an anisotropic structure. In order to form an anisotropic structure in the PE matrix, the polymer was extruded through a twin-screw extruder, and the structure was controlled by varying the extrusion conditions. Depending on conditions, the second component formed a film, thread and droplet structure. If the second component was kept rigid, the morphology evolution could be delayed and the second component could maintain its film or thread structure without further relaxation. In par­ticular, the second component of the thread structure made a physical network and gave rise to remarkable strain hardening behavior under high extension. This study suggests a new method that induces strain hard­ening behavior by introducing a physically networked second component into the linear polymer melt. This result is anticipated to improve the processibility of linear polymers especially when extensional flow is dominant, and to contribute to our understanding of strain hardening behavior.

• Journal of Integrative Natural Science
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• v.1 no.3
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• pp.250-253
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• 2008

New issues arise as to surface characterization, quantification and interface formation. Surface and interface control of CdSe nanocrystal systems, one of the most studied and useful nanostructures. Semiconductor quantum dots (QDs) have been the subject of much interest for both fundamental reseach and technical applications in recent years, due mainly to their strong size dependent properties and excellent chemical processibility. In this dissertation, the synthesis of CdSe quantum dots were synthesized by pyrolysis of high-temperature organometallic reagents. In order to modify the size and quality of quantum dots, we controlled the growth temperature and the relative amount of precursors to be injected into the coordinating solvent. Moreover, an effective surface passivation of monodisperse nanocrystals was achieved by overcoating them with a higher-band-gap material. Synthesized CdSe quantum dots were studied to evaluate the optical, electronic and structural properties using UV-absorption, and photoluminescence measurement.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.3.2-3.2
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• 2010

There have been many efforts to utilize the outstanding properties of graphene for macroscopic applications such as transparent conducting films useful for flexible/stretchable electronics. However, the lack of efficient synthesis, transfer, and doping methods limited the scale and the quality needed for the practical production of graphene films. In this presentation, we introduce ultra-large scale (~30 inch) synthesis, roll-to-roll transfer, and chemical doping of graphene films showing excellent electrical and physical properties suitable for practical applications. Considering the outstanding scalability/processibility of roll-to-roll and CVD methods and the extraordinary flexibility/conductivity of graphene films, we expect the commercial production and application electrodes replacing the use of ITO can be realized in near future.

• Carbon letters
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• v.11 no.4
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• pp.347-356
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• 2010

Recently, the use of thermal conductive polymeric composites is growing up, where the polymers filled with the thermally conductive fillers effectively dissipate heat generated from electronic components. Therefore, the management of heat is directly related to the lifetime of electronic devices. For the purpose of the improvement of thermal conductivity of composites, fillers with excellent thermally conductive behavior are commonly used. Thermally conductive particles filled polymer composites have advantages due to their easy processibility, low cost, and durability to the corrosion. Especially, carbon-based 1-dimensional nanomaterials such as carbon nanotube (CNT) and carbon nanofiber (CNF) have gained much attention for their excellent thermal conductivity, corrosion resistance and low thermal expansion coefficient than the metals. This paper aims to review the research trends in the improvement of thermal conductivity of the carbon-based materials filled polymer composites.

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.112-116
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• 2010

Prepared CdSe nanoparticles were systems, one of the most studied and useful nanostructures. Semiconductor quantum dots (QDs) have been the subject of much interest for both fundamental reseach and technical applications in recent years, due mainly to their strong size dependent properties and excellent chemical processibility. CdSe nanocrystals were synthesized by using sol-gel process. Synthesized CdSe quantum dots were studied to evaluate the optical, electronic and structural properties using UV-absorption, and photoluminescence (PL) measurement. Prepared CdSe nanoparticles were subjected to sense hydrofluoric acid. Photoluminescence was quenched upon adding of hydrofluoric acid.