• 치위생과학회지
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• 제6권4호
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• pp.231-235
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• 2006

본 연구는 부가중합형실리콘인상재의 정밀 인상채득에 영향을 미치는 요인, 압축변형률, 탄성회복률, 점주도와 젖음성을 평가하기 위하여 현재 시판되고 있는 4종류의 인상재 Examixfine(GC), Aquasilultra(Dentsply), Extrude(Kerr), Perfect-F(Handae)를 이용하여 실험하였다. 실험 데이터는 SPSSWIN 12.0을 사용하여 분석하였고, 결과는 다음과 같다. 1. 압축변형률은 Extrude가 4.86%로 가장 낮게 나타났고, Examixfine이 6.78%로 가장 크게 나타났다. Examixfine과 Perfect-F 사이에는 유의한 값의 차이가 없었으나, 다른 인상재 그룹에서는 유의성이 있었다. (p < 0.001). 2. Extrude의 탄성회복률이 99.83%로 가장 크게 나타났고, Perfect-F가 96.54%로 가장 낮게 나타났다. Examixfine과 Aquasilultra 간에는 유의성이 없었으나, 다른 인상재그룹간에는 유의한 차이가 있었다(p < 0.001). 3. 점주도의 측정결과에서 Examixfine이 점주도 값이 45.12mm로 가장 높았고, Perfect-F의 경우 40.28 mm로 가장 낮은 점주도 값을 나타내었다. Examixfine과 Aquasilultra, Extrude와 Perfect-F 간에는 유의한 차이가 나타나지 않았다(p > 0.001). 4. 젖음성에서는 Aquasilultra가 $47.85^{\circ}$로 가장 접촉각이 작게 나타나 친수성이 가장 우수하게 나타났고, Perfect-F는 접촉각이 $94.89^{\circ}$로 접촉각이 크게 나타나 소수성으로 나타났다. 인상재 종류별로도 각각 유의성이 존재하였다 (p < 0.001). 5. 접촉각은 압축변형률(p < 0.01), 탄성회복률(p < 0.01), 점주도(p < 0.05)와 상관관계가 있었고, 탄성회복률과 점주도 와는 음의 상관관계를 보였다. 압축변형률은 접촉각, 탄성회복률과 상관관계가 있었고(p < 0.01), 탄성회복률과 음의 상관관계를 나타냈다. 탄성회복률은 접촉각, 압축변형률과 음의 상관관계를 가지고 있었고(p < 0.01), 점주도도 접촉각과 음의 상관관계를 보였다(p < 0.05).

• 한국결정성장학회지
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• 제19권6호
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• pp.288-292
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• 2009

LPD법을 이용하여 유리 기판 위에 발수/친수 패터닝 기판을 제조하였다. 발수 표면은 거친 표면을 갖는 ZnO 박막을 FAS를 이용한 표면 개질에 의하여 만들어졌고, 친수 표면은 자외선을 조사하여 FAS를 제거함으로써 만들어졌다. Hexagonal ZnO rod는 LPD법에 의하여 ZnO seed 층이 코팅된 유리 기판 위에 수직으로 성장되었다. 침적시간이 증가함에 따라 ZnO rod의 직경과 두께는 증가하였다. 제조된 ZnO 박막의 표면구조, 두께, 결정구조, 투과율과 접촉각은 FE-SEM, XRD, UV-vis와 contact angle meter를 이용하여 측정하였다. $20^{\circ}{\sim}30^{\circ}$의 접촉각을 갖는 친수 ZnO 박막은 FAS 표면 처리에 의해 $145^{\circ}{\sim}161^{\circ}$의 접촉각을 갖는 표면으로 바뀌었다. 제조된 발수 표면은 $300\;{\mu}m$, 3 mm의 dot size를 갖는 shadow mask를 이용하여 자외선을 조사하여 패터닝 되었다. 최종적으로 자외선이 조사된 발수 표면은 친수 표면으로 바뀌었다.

• 폴리머
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• 제36권2호
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• pp.124-130
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• 2012

본 연구의 목적은 전기방사법을 사용하여 poly(L-lactide-$co$-${\varepsilon}$-caprolactone) (PLCL)과 marine collagen (MC)이 혼합된 나노섬유를 제조하는 것이다. 전기방사된 나노섬유의 직경과 형태는 여러 공정 변수에 의해서 변화되는데, PLCL과 MC의 혼합비, 노즐과 콜렉터와의 거리, 노즐의 직경, 용액의 방출 속도 그리고 전기장의 세기 변화에 따라 나노파이버의 직경을 주사전자현미경을 통해서 분석하였다. 또한 제조된 나노파이버의 표면변화를 확인하기 위해 물과의 접촉각을 측정하였으며, 나노파이버의 세포 친화성을 평가하기 위해 MG-63을 이용하여 생존율과 흡착형태를 주사전자현미경과 형광현미경을 통해서 관찰하였다. 이와 같은 연구 결과, 방사거리, MC의 함량, 전기장의 세기가 증가할수록 제조된 나노파이버의 평균직경은 감소하는 경향을 나타냈다. 또한 MC의 함량이 증가할수록 나노파이버의 친수성이 증가하였고 세포독성은 관찰되지 않았다. 이에 따라 해양유래 생물에서 추출한 콜라겐은 조직공학용 소재에 새롭게 사용될 수 있을 것으로 예상된다.

• 한국염색가공학회지
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• 제23권4호
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• pp.227-232
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• 2011

Zein is a hydrophobic protein produced from maize and has great potential in a number of industrial applications, such as food, food coating and food packaging. To obtain suitable electrospinning conditions for thinner and uniform zein nanofiber mats, a series of experiments was conducted on various volume ratios (v/v) of ethanol/water solutions with different zein concentrations. The prepared zein nanofiber mats were characterized by field emission scanning electron microscopy and contact angle measurements. Uniform zein fibers with a average diameter in the nanometer scale (300~500 nm) could be prepared from 30 wt.% zein in 7/3 (v/v) ethanol/water solutions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.346.2-346.2
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• 2016

The rear side contact recombination in the crystalline silicon solar cell could be reduced by back surface field. We formed polycrystalline silicon as a back surface field through crystallization of amorphous silicon. A thin silicon oxide applied to the passivation layer. We used quasi-steady-state photoconductance measurement to analyze electrical properties with various annealing condition. And, blister formed on surface of wafer during the annealing process. We observed the blister after varied annealing process with wafer of various surface. Shape and density of blister is influenced by various annealing temperature and process time. As the annealing temperature became higher, the average diameter of blister is decreased and total number of blister is increased. The sample with the $600^{\circ}C$ annealing temperature and 1 min annealing time exhibited the highest implied open circuit voltage and lifetime. We predicted that the various shape and density of blister affects the lifetime and implied open circuit voltage.

• ETRI Journal
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• 제36권3호
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• pp.361-366
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• 2014

In this paper, a new, simple capacitive tilt sensor with a metallic ball is proposed. The proposed tilt sensor has only two electrodes and a metallic ball, and this design assists in managing the inherent contact problem in measuring tilt angles. Capacitive sensing, compared with other types of tilt sensor, has many advantages such as simplicity, noncontact measurement, long-throw linear displacement, and sub-micron plate spacing. Its design and fabrication process are significantly simpler than previous types of tilt sensors. The dimensions of the prototype tilt sensor are $20mm{\times}20mm$, and the diameter of the polystyrene tube is 5 mm with a tube thickness of 0.15 mm. An analytical study of the prototype capacitive tilt sensor was undertaken, and the experimental results demonstrate the relationship between the tilt angles and measured capacitances compared with the analytical study.

• 펄프종이기술
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• 제34권1호
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• pp.30-36
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• 2002

The objective of this study was to investigate the viscosity of coating colors and ink-jet printing properties with different coating colors with various blending ratios of silica based pigments. The volume of pigments was measured to evaluate the effect of the pigments on the viscosity of coating colors. Contact angle, the change of ink diameter, optical density, and the area and perimeter of a printed let-ter were evaluated to examine the effect of the ink absorption on the ink-jet printing properties. Generally, as the amount of silica pigments Increased the ink-jet printing quality improved. But this caused an increase of the overall coating viscosity.

• 한국안전학회지
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• 제18권1호
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• pp.19-27
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• 2003

This paper presented an experimental modal analysis of clamped perforated rectangular plates submerged in water. The penetration of holes in the plates had a triangular pattern with P/D (pitch to diameter) 1.750, 2.125, 2.500, 3.000 and 3.750. The natural frequencies of the perforated plates in air were obtained by the Rayleigh-Ritz method and compared with the experimental results. Good agreement was obtained between the analytical solution and experimental result. The experimental results in water showed that the mode shapes are not sensitive to the depth of submergence. The natural frequencies were shown to decrease drastically once the perforated plates come in contact with water. However, the natural frequencies decrease with the depth of submergence until a certain depth is reached, and become the asymptotic values beyond this depth of submergence. The depth of submergence did not affect the damping ratio greatly.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.643-645
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• 2008

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1um) and gold film (1-2um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed microstructure of grains of about 100nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권1호
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• pp.10-14
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• 2004

A large area electron beam generator has been developed for industrial applications, for example, waste water cleaning, flue gas treatment, and food pasteurization. The operational principle is based on the emission of secondary electrons from the cathode when ions in the plasma contact the cathode, which are accelerated toward the exit window by the gradient of the electric potential. Conventional electron beam generators require an electron beam scanning mechanism because a small area thermal electron emitter is used. The electron beam of the large area electron beam generator does not need to be scanned over target material because the beam area is considerable. We have fabricated a large area electron beam generator with peak energy of 200keV, and a beam diameter of 200mm. The electron beam current has been investigated as a function of accelerating voltage and distance from the extracting window while its radial distribution in front of the extracting window has been also measured.