• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.108-115
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• 2018

In bone tissue engineering, polycaprolactone (PCL) is one of the most widely used biomaterials to manufacture scaffolds as a synthetic polymer with biodegradability and biocompatibility. The polymer deposition system (PDS) with four axis heads, which can dispense bio-polymers, has been used in scaffold fabrication for tissue engineering applications. A dual-head deposition technology of PDS is an effective technique to fabricate 3D scaffolds. The electrospinning technology has been widely used to fabricate porous and highly interconnected polymer fibers. Thus, PDS can fabricate nanofiber-combined hybrid scaffolds using fused deposition modeling (FDM) and electrospinning methods. This study aims to fabricate nanofiber-combined scaffolds with uniform nanofibers using PDS. The PCL nanofibers were fabricated and evaluated according to the fabrication process parameters. PCL nanofibers were successfully fabricated when the applied voltage, tip-to-collector distance, flow rate, and solution concentration were 5 kV, 1 cm, 0.1 ml/h, and 8 wt%, respectively. The cell proliferation was evaluated according to the electrospinning time. Scanning electron microscopy was used to acquire images of the cross-sectioned hybrid scaffolds. The cell proliferation test of the PCL and nanofiber-combined hybrid scaffolds was performed using a CCK-8 assay according to the electrospinning time. The result of in-vitro cell proliferation using osteosarcoma MG-63 cells shows that the hybrid scaffold has good potential for bone regeneration.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.512-523
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• 2018

Background: 20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD. Methods: MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model. Results: A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient $r^2=0.929-0.947$). Conclusion: The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.86-92
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• 2011

The diagnosis studies of the process of chemical vapor deposition were carried out by using in-situ particle monitor (ISPM) and self-plasma optical emission spectroscopy (SPOES). We used the two kinds of equipments such as the silicon plasma enhanced chemical vapor deposition system with silane gas and the borophosphosilicate glass depositon system for monitoring. Using two sensors, we tried to verify the diagnostic and in-situ sensing ability of by-product gases and contaminant particles at the deposition and cleaning steps. The processes were controlled as a function of precess temperature, operating pressure, plasma power, etc. and two sensors were installed at the exhaust line and contiguous with each other. the correlation of data (by-product species and particles) measured by sensors were also investigated.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.77-85
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• 1991

In this study we have investigated surface morphologies of as-deposited silicon films on the various deposition conditions using LPCVD(Low Pressure Chemical Vapor Deposition) System. The processing conditions such as deposition temperature, pressure and flow rate of $SiH_4$ gas were found to determine the surface morphology. The optimum temperature of maximum effective surface area increased with increasing the deposition pressure and the flow rate of $SiH_4$ gas, These experimental results were also in quite good agreement with the equation derived under the assumption that the maximum effective surface area is obtained on the condition of maximum nucleation rate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.380-381
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• 2007

This paper reports on the deposition conditions and properties of ITO films used as electrode layer in a organic light emitting diodes on a PET substrate. The deposition technique employed was specially designed roll-to-roll sputtering. The oxide was deposited at room temperature in an argon and oxygen plasma on a transparent conducting ITO layer on a PET film. The influence of deposition parameters such as DC power, working pressure and oxygen partial pressure has been investigated, in order to obtain the best compromise between a high deposition rate and adequate electro-optical properties. Electrical and optical properties of ITO films were analyzed by Hall measurement examinations with van der pauw geometry at room temperature and UV/Vis spectrometer analysis, respectively. In addition, the structural properties and surface smoothness were measured by x-ray diffraction and scaning electron microscopy, respectively. From optimized ITO films grown by roll-to-roll sputter system, good electrical$(6.44{\times}10^{-4}\;{\Omega}-cm)$ and optical(above 86 % at 550 nm) properties were obtained. Also, the ITO films exhibited amorphous structure and very flat surface beacause of low deposition temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.250-256
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• 2014

In this study, we deposited and investigated ${\mu}c$-Si:H thin films prepared by Plasma Enhanced Chemical Vapor Deposition(PECVD) system. To deposition silicon thin films, we controlled $SiH_4$ gas concentration, RF input power, and heater temperature. According to the experiments, the more $SiH_4$ gas concentration increased, deposition rate also increased but crystalline property decreased at the same conditions. In the RF input power case, deposition rate and crystalline property increased together when the input power increased from 100[W] to 300[W]. If RF input power was 300[W], deposition rate has reached saturation point. In the heater temperature, deposition rate increased when heater temperature increased. Crystalline property maintained a certain level until heater temperature was $250[^{\circ}C]$. And then it was a suddenly increased. Multistep method has been proposed to improve the quality of ${\mu}c$-Si:H thin film. $SiH_4$ gas was injected with a time interval. According to the experiments, crystallite ratio improve about 20~60[%] and photo conductivity increased up to six times.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.321-329
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• 2016

Based on the results of groundwater flow system modeling for a hypothetical deep geological repository site, quantitative and spatial distributions of groundwater flow rates at the positions of deposition holes, groundwater travel length and time from the positions to the surface environment were analyzed and used to suggest a method for determining locations of deposition holes. The hydraulic head values at the depth of the deposition holes and a particle tracking method were used to calculate the ground-water flow rates and groundwater travel length and time, respectively. From the results, an approach to designing a layout of deposition holes was suggested by selecting relatively favorable positions for maintaining performance of the disposal facility and screening some positions of deposition holes that did not comply with specific constraints for the groundwater flow rates, travel length and time. In addition, a method for determining a geometrical direction for extension of the disposal facility was discussed. Designing the layout of deposition holes with the information of groundwater flow at the disposal depth can contribute to secure performance and safety of the disposal facility.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1818-1820
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• 1999

This paper presents direct ${\mu}c$-Si:H thin film growth on the glass substrates using RPCVD system (remote plasma chemical vapor deposition) in low temperature. Hydrogenated micro-crystalline silicon deposited by RPCVD system in low temperature is very useful material for photovoltaic devices, sensor applications, and TFTs (thin film transistors). Varying the deposition conditions such as substrate temperature, gas flow rate, reactive gas ratio $(SiH_4/H_2)$, total chamber pressure, and rf power, we deposited ${\mu}c$-Si:H thin films on the glass substrates (Corning glass 1737). And then we measured the structural and electrical properties of the films.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1799-1803
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• 2003

The possibility of lycopene affecting egg yolk pigmentation was studied with lycopene diets containing 0, 4, 8, and $12{\mu}g/g$ meal, respectively. The addition of lycopene above $4{\mu}g/g$ meal significantly improved yolk color after four days of supplementation. The transfer of lycopene into egg yolk was confirmed by thin layer chromatography, and high-performance liquid chromatography-mass spectrometry (HPLC-MS). The deposition rate of lycopene into egg yolk was approximately 2%, which was quantitatively determined using a HPLC with a UV detector. The result indicates that lycopene is a good candidate for egg yolk pigmentation and for making functional eggs.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.110-115
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• 2007

A plasma enhanced atomic layer deposition(PEALD) system has been constructed adopting an inductively coupled plasma(ICP) source with an ALD system, and its plasma generation was carried out. Cobalt thin films were deposited on a p-type Si(100) wafer at $230^{\circ}C$. $Co_{2}(CO)_{6}$ was used as a cobalt precursor, $NH_{3}$ as a reactant, and Ar as a carrier and purge gas. The properties of the thin films were investigated using field emission scanning electron microscopy(FESEM) and auger electron spectroscopy(AES). Large amounts of impurities were found in both the ALD film and the PEALD film, however, the amount of impurities in the PEALD film was reduced to about 50 % compared to that in the ALD film. It was found that $NH_{3}$ plasma, very effectively, induces the reaction with carbon in a cobalt precursor.