• 한국표면공학회지
• /
• 제27권2호
• /
• pp.74-82
• /
• 1994

The structure and properties such as adhesion and corrosion resistance of Cr and $Cr_2O_3$ films, deposited on steel plates by the vacuum evaporation method, were investigated. According to the ESCA and AES analy-sis, it could be concluded that chromium oxide with uniform composition could be formed on the steel sub-strate. The deposited Cr and $Cr_2O_3$ films had high adhesion strength, and they did not peeled off by the tape test. The adhesion property, however, was deteriorated as the film thciknes increased. After bending of the deposited specimen many cracks were observed by SEM, and they were assumed to have propagated along co-lumnar boundaries by the bending test. The corrosion resistance of the films was not generally good, which in-dicates that the films had a porous structure with a large number of defects such as pin holes and voids.

• 한국안전학회지
• /
• 제28권2호
• /
• pp.37-41
• /
• 2013

In this work, we report the effect on the volatole organic compounds(VOCs) sensing properties of Copper phthalocyanine(CoPc) and Dilithium phthalocyanine(DiLiPc) thin films onto alumina substrates. Use evaporation method and the spin-coated method for sensing device. The materials of metallophthalocyanine macrocyclic compound solutions blended with N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine and/or Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] solutions. The influence of the blended in with metallophthalocyanine macrocyclic compounds on the resistance have been measured and analyzed in five different volatole organic compounds. The following results were obtained: The AFM 3D image of thin films deposited on metallophthalocyanine macrocyclic compound shows that the surfaces roughness were about CuPc 4.1~14.3 nm(7.5~8.1%), DiLiPc 10.3~22.2 nm(7.9~11.5%). The resistances decreases upon increasing the concentration of vapor organic compounds to CuPc and DiLiPc thin films. That thin films blended Copper phthalocyanine(CoPc) and Dilithium phthalocyanine(DiLiPc) with N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine and/or Poly[2-methoxy--5-(2'-ethylhexyloxy)-1,4-phenylenevinylene]. The resistances of blended thin films with N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine and/or Poly[2-methoxy--5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] decreases upon increasing the concentration of volatole organic compounds(VOCs) on DiLiPc than CuPc compound thin films.

• 한국가스학회지
• /
• 제22권4호
• /
• pp.1-6
• /
• 2018

IMO에서 규정하는 LNG 벙커링 선박용 연료 탱크 중 C형 가압탱크는 내외 2중 용기로 구성된 초저온 탱크에 $10^{-2}$ Torr 진공과 펄라이트 단열재가 충전되는 것이다. 그러나 이 단열방식은 LNG 기화량이 하루당 2.0 % 내외로 증발율이 커서 보다 단열효과가 좋은 탱크가 요구되어 진다. 본 연구에서는 내외탱크 사이에 고진공을 적용하고 외부탱크의 내벽체에 중간 단열로 펄라이트 진공단열을 적용하는 단열 방식을 새로이 고안하여 열해석을 수행하였다. 이의 장점으로는 진공 공간의 감소로 고진공 형성 시간을 크게 감소되고, 진공도 $10^{-4}$ Torr 이하에서 하루당 증발율이 0.16 %에 불과한 매우 효율이 높은 탱크 단열방식이 되었다. 만약 현재의 IMO C형 탱크의 진공펄라이트 단열에서 진공이 파괴되는 경우, C형 탱크는 하루당 4.9 %의 증발이 발생하고 새 고안 탱크는 5.23 %로 거의 동일하게 된다.

• 한국응용과학기술학회지
• /
• 제27권4호
• /
• pp.391-398
• /
• 2010

Soybean lecithin liposomes composed phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidic acid were prepared by using the previously developed supercritical reverse phase evaporation method. The effect of phospholipid composition on the formation of liposomes and physicochemical properties were examined by means of trapping efficiency measurements, transmission electron microscopy, dynamic light scattering and zeta potential measurements. The trapping efficiency of liposomes for D-(+)-glucose made of CNA-Ⅰ which contains approximately 95% phosphatidyl choline is higher than that of CNA-II and CNA-O which contain approximately 32% phosphatidyl choline. However there is no any difference between the trapping efficiency of liposomes for D-(+)-glucose made of CNA-II which has saturated hydrocarbons tails and that of liposomes made of CNA-O which has unsaturated hydrocarbon chains. The electron micrographs of liposomes made of CNA-II and CNA-O show small spherical liposomes with diameter of $0.1\sim0.25{\mu}m$, while that of CNA-I shows large unilamellar liposomes with diameter of $0.2\sim1.2{\mu}m$. These results clearly show that phospholipid structure of phosphatidylcholine allows an efficient preparation of large unilamellar liposomes and a high trapping efficiency for water soluble substances. Liposomes made of CNA-II and CNA-O remained well-dispersed for at least 14 days, while liposome suspension made of CNA-I separated in two phase at 14 days due to aggregation and fusion of liposomes. The dispersibility of liposomes made of CNA-I is lower than that of CNA-II and CNA-O due to the smallar zeta potential of CNA-I.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.382-382
• /
• 2012

CIGS thin films have received great attention as a promising material for solar cells due to their high absorption coefficient, appropriate bandgap, long-term stability, and low cost production. CIGS thin films are deposited by various methods such as co-evaporation, sputtering, spray pyrolysis and electro-deposition. The deposition technique is one of the most important processes in preparing CIGS thin film solar cells. Among these methods, co-evaporation is one of the best technique for obtaining high quality and stoichiometric CIGS films. However, co-evaporation method is known to be unsuitable for commercialization. The sputtering is known to be very effective and feasible process for mass production. In this study, CIGS thin films have prepared by rf magnetron sputtering using a $Cu(In_{1-x}Ga_x)Se_2$ single quaternary target without post deposition selenization. This process has been examined by the effects of deposition parameters on the structural and compositional properties of the films. In addition, we will explore the influences of substrate temperature and additional annealing treatment after deposition on the characteristics of CIGS thin films. The thickness of CIGS films will be measured by Tencor-P1 profiler. The crystalline properties and surface morphology of the films will be analyzed using X-ray diffraction and scanning electron microscopy, respectively. The optical properties of the films will be determined by UV-Visible spectroscopy. Electrical properties of the films will be measured using van der Pauw geometry and Hall effect measurement at room temperature using indium ohmic contacts.

• 멤브레인
• /
• 제10권3호
• /
• pp.130-138
• /
• 2000

건/습식 상전환법을 이용하여 비대칭 polyethersulfone (PES) 기체분리막을 제조하였으며, $CO_2$, $N_2$등의 기체에 대한 투과특성을 조사하였다. 분리막 제조에 있어서 주요 변수인 캐스팅 용액과 증발시간 등이 분리막의 구조에 미치는 영향을 파악하고 투과특성을 조사하여 최적의 제조조건을 확립하였다. 또한 제조된 분리막의 표피층에 존재하는 pin-hole과 같은 결점을 보완하기 위하여 실리콘 수지를 코팅하여 그 투과특성의 변화를 조사하였다. 실리콘 수지 코팅이 결점을 보완하는데 효과적임을 확인하였다. 본 연구에서 분리막 제조에 주로 사용한 캐스팅 용액은 PES, 14-methyl-2-pyrrolidone, 아세톤, 에탄올로 구성되었으며, 응고제로는 증류수를 사용하였다. 캐스팅 용액 중의 PES 함량이 높아질수록, 휘발성 유기용매의 비율이 높아질수록, 증발시간이 길수록, 에탄을 첨가제의 농도가 낮을수록 $CO_2$/$N_2$의 선택도는 높아지고 투과도는 낮아지는 결과를 보였다. 최적의 분리막 제조조건 하에서 얻어진 분리막의 분리성능은 $CO_2$/$N_2$의 선택도가 61이고 $CO_2$의 투과도는 21 GPU인 우수한 결과를 보였다.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2007년도 High Temperature Superconductivity Vol.XVII
• /
• pp.6-6
• /
• 2007

• 한국자기학회지
• /
• 제3권4호
• /
• pp.269-276
• /
• 1993

Co/Pd 다층박막에서 두 sublayer의 층수비($n_{Co}/n_{Pd}$ = 1/4, 2/4, 3/4, 5/4), 기판온도 ($실온,\;100,\;150,\;200\;^{\circ}C$)를 달리하는 시료를 열진공 증착방법으로 제작하고 이에 대한 Hall 이력곡선을 측정하였다. 이때 나타나는 다야한 형태의 이력곡선을 Co와 Pd sublayer의 자화에 의한 transverse Hall effect 항과 magnetoresistivity 항이 중첩된 것으로 보고 이를 최적 fiting 방법으로 분해하였다. 이 결과 시료 전체의 계면 영역에 걸쳐 강자성과 반강자성인 두 자화상태가 공존하며 이들의 exchange anisotropy의 크기와 반강자성 물질에 의한 강자성 물질의 자벽 고착 효과에 따라 uniaxal 또는 unidirectional easy axis 형의 Hall 이력곡선을 형성하는 것으로 나타났다.

• Bulletin of the Korean Chemical Society
• /
• 제33권10호
• /
• pp.3208-3212
• /
• 2012

Controlled drug delivery systems employing microparticles offer lots of advantages over conventional drug dosage formulations. Microencapsulation technique have been conducted with biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA) for its adjustable biodegradability and biocompatibility. In this study, we evaluated two techniques, oil-in-water (o/w) emulsion solvent evaporation and spray drying, for preparation of polymeric microparticles encapsulating a newly synthesized drug, SS-AG20, for the long-term drug delivery of this low-molecular-weight drug with a very short half-life. Drug-loaded microparticles prepared by the solvent evaporation method showed a smoother morphology; however, relatively poor encapsulation efficiency and drastic initial burst were discovered as drawbacks. Spray-dried drug-loaded microparticles had an imperfect surface with pores and distorted portions so that its initial burst was critical (70.05-87.16%) when the preparation was carried out with a 5% polymeric solution. By increasing the concentration of the polymer, the morphology was refined and undesirable initial burst was circumvented (burst was reduced to 35.93-74.85%) while retaining high encapsulation efficiency. Moreover, by encapsulating the drug with various biodegradable polymers using the spray drying method, gradual and sustained drug release, for up to 2 weeks, was achieved.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.193-197
• /
• 2000

BSCCO thin films are fabricated via a co-deposition process by an ion beam sputtering with an ultra-low growth rate, and sticking coefficients of the respective elements are evaluated. The sticking coefficient of Bi element exhibits a characteristic temperature dependence : almost a constant value of 0.49 below 73$0^{\circ}C$ and decreases linearly with temperature over 73$0^{\circ}C$. This temperature dependence can be elucidated from the evaporation and sublimation rates of bismuth oxide, Bi$_2$O$_3$, from the film surface. It is considered that the liquid phase of the bismuth oxide plays an important role in the Bi(2212) phase formation in the co-deposition process.