• Proceedings of the KACD Conference
• /
• 2001.11a
• /
• pp.578.1-578
• /
• 2001

The aim of this study was to evaluate the efficiency of the recently introduced light curing units to polymerize a light curing resin composite. Four light curing units XL 3000, Optilux 500 for halogen light source, Apollo 95E for plasma arc and Easy cure for LED (blue-light Emitting Diode) were evaluated. Radiometer was used for measure the light intensity.(omitted)

• Resources Recycling
• /
• v.22 no.2
• /
• pp.18-21
• /
• 2013

In this study, surface modification of wood powder by atmospheric pressure plasma treatment was investigated. The composites were manufactured using wood powder and polypropylene(wood powder : PP = 55 wt% : 45 wt%). Atmospheric pressure plasma was treated as condition of 3KV, $17{\pm}1$KHz, 2 g/min. Helium was used as carrier gas and monomer such as hexamethyl-disiloxane(HMDSO) was used to modify surface property by plasma polymerization. The tensile strength of untreated waste wood powder(W3) and homogeneous wood powder(H3) were about 18.5 MPa, 21.5 MPa while the tensile strength of plasma treated waste wood powder(PW3) and homogeneous wood powder(PH3) were about 21.2 MPa, 23.4 MPa, respectively. And tensile strength of W3 and H3 were improved by 14.6% and 8.8%, respectively. From the results for mechanical property, morphological analysis, we obtained improved interfacial bonding of polypropylene and wood powder modified by plasma treatment.

• The Journal of Advanced Prosthodontics
• /
• v.4 no.2
• /
• pp.93-96
• /
• 2012

PURPOSE. The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS. A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (${\alpha}$=.05). RESULTS. ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance ($P$ <.001). CONCLUSION. Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.

• Macromolecular Research
• /
• v.11 no.6
• /
• pp.511-513
• /
• 2003

Hydroxyl groups were introduced onto the surface of a silicon wafer by O$_2$ plasma treatment. Poly(l-lactide) (1-PLA) was attached onto the surface-modified silicon wafer by the ring-opening polymerization of l-lactide using the hydroxyl group as an initiator. Lamellar single crystals of 1-PLA were grown directly on the 1-PLA-attached silicon wafer from a 0.025% solution in acetonitrile at 5$^{\circ}C$. A well-separated, lozenge-shaped, monolayered lamellar single crystal was prepared because the 1-PLA-attached silicon wafer acts as an initial nucleus.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1636-1638
• /
• 1996

MMA-Styrene-Tetramethyltin(MST) thin films were fabricated by plasma polymerization method, and their electrical properties were confirmed by IR and GPC. The electrical conductivity increased with increasing temperature, and the adsorption current hardly appeared. The high-field electrical conduction mechanism is the electronic one such as schottky, and the activation energy is about 1.1 eV.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.11a
• /
• pp.152-155
• /
• 1994

The purpose of this paper is to develope an electron beam resist by the plasma polymerization. Plasma co-polymerized resist was prepared using an interelectrode gas-flow-type reactor. And then delineated pattern in the resist was developed with gas flow type reactor using Ar and O$_2$ gas as etching gas. We study about the effects of discharge power and mixing rate of the copolymerized thin film. The characteristics of molecular structure of thin film was investigated by FT-lR, DSC and GPC, and then was discussed in relation to its quality as a resist.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2014.11a
• /
• pp.286-288
• /
• 2014

This study deals with the catalyst free radio frequency plasma assisted polymerization of ethylene glycol using nitrogen as reactive gas to modify the surface chemistry and morphology. The deposited film was characterized through various analysis techniques i.e. surface profilometry, Forier transform infrared spectroscopy, water contact angle and UV-visible spectroscopy to analyze film thickness, chemical structure, surface energy and optical properties respectively. The surface topography was analyzed by Atomic force microscopy. It was observed that the ethylene oxide behaviour and optical transmittance of the film were reduced with the introduction of nitrogen gas due to higher fragmentation of monomer. However the hydrophilic behavior of the film improved due to formation of new water loving functional groups suitable for biomedical applications.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1349_1350
• /
• 2009

Thin films of pp(ST-Co-VA) were fabricated by plasma deposition polymerization (PVDPM) technique. Properties of the plasma polymerized pp(ST-Co-VA) thin films were investigated for application to semiconductor device as insulator. Thickness, dielectric property, composition of the pp(ST-Co-VA) thin films were investigated considering the relationship with preparation condition such as gas pressure and deposition time. In order to verify the possibility of application to organic thin film transistor, a pentacene thin film was deposited on the pp(ST-Co-VA) insulator by vacuum thermal evaporation technique. Crystalline property of the pentacene thin film was investigated by XRD and SEM, FT-IR. Surface properties at the pp(ST-Co-VA)/pentacene interface was investigated by contact angle measurement. The pp(ST-Co-VA) thin film showed a high-k (k=4.6) and good interface characteristic with pentacene semiconducting layer, which indicates that it would be a promising material for organic thin film transistor (OTFT) application.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.458-458
• /
• 2010

The process window for the etch selectivity of silicon nitride ($Si_3N_4$) layers to extreme ultra-violet (EUV) resist and variation of line edge roughness (LER) of EUV resist were investigated durin getching of $Si_3N_4$/EUV resist structure in a dual-frequency superimposed capacitive coupled plasma (DFS-CCP) etcher by varying the process parameters, such as the $CH_2F_2$ and $N_2$ gas flow rate in $CH_2F_2/N_2$/Ar plasma. The $CH_2F_2$ and $N_2$ flow rate was found to play a critical role in determining the process window for infinite etch selectivity of $Si_3N_4$/EUV resist, due to disproportionate changes in the degree of polymerization on $Si_3N_4$ and EUV resist surfaces. The preferential chemical reaction between hydrogen and carbon in the hydrofluorocarbon ($CH_xF_y$) polymer layer and the nitrogen and oxygen on the $Si_3N_4$, presumably leading to the formation of HCN, CO, and $CO_2$ etch by-products, results in a smaller steady-state hydrofluorocarbon thickness on $Si_3N_4$ and, in turn, in continuous $Si_3N_4$ etching due to enhanced $SiF_4$ formation, while the $CH_xF_y$ layer is deposited on the EUV resist surface. Also critical dimension (and line edge roughness) tend to decrease with increasing $N_2$ flow rate due to decreased degree of polymerization.

• Membrane Journal
• /
• v.10 no.4
• /
• pp.198-204
• /
• 2000

Pervaporation membranes were fabricated by low temperature plasma treatment the concentrate butanol solution from fermentation process. Effects of power, reaction time, and monomer flow rate were examined to optimize the (W!FM)t value as 4.0389 x 109 J . min/kg. Various organic compounds were tested in plasma treatment. Contact angle and relative sorption ratio were examined in terms of membrane performance. With the increase of contact angle and relative sorption ratio separation factor was enhanced from 0.186 to 3.525. and butanol flux increased from 0.042 to 0.567 kglm2. hr. Hydrophobicity of the membrane increased the affinity with butanoL Heat of mixing for monomer with butanol was examined, but failed to find the trend, because plasma polymerization of monomer produced the new compounds much different from monomers.