• KSBB Journal
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• 제20권5호
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• pp.338-340
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• 2005

변성제 (urea)와 환원제에 의해 완전히 풀린 상태의 lipase도 PEG에 의해 수식되는 것을 관찰하였다. 또한 mPEG-aldehyde로 수식된 mono-PEGylate과 di-PEGylate을 변성제와 환원제를 이용해 unfolding 시킨 후 희석에 의한 재접힘 시킨 결과, lipase에 공유결합된 PEG 분자는 재접힘 수율에 거의 영향을 미치지 않는 것으로 나타났다. 따라서 내포체 단백질을 대상으로 변성된 상태에서 PEGylation시킨 후 in vitro 재접힘 공정을 통해 PEGylation된 상태의 재생된 단백질을 회수할 수 있는 통합공정의 타당성을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1603-1607
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• 2012

The effects of plating process on the surface coverage of the accelerator were investigated in terms of Cu superfilling for device metallization. When a substrate having 500 nm-wide trench patterns on it was immersed in an electrolyte containing poly (ethylene glycol) (PEG)-chloride ion ($Cl^-$)-bis(3-sulfopropyl) disulfide (SPS) additives without applying deposition potential for such a time of about 100s, voids were generated inside of the electrodeposit. In time-evolved electrochemical analyses, it was observed that the process (immersion without applying potential) in the electrolyte led to the build-up of high initial coverage of SPS-Cl on the surface, resulting in the fast saturation of the coverage. Repeated experiments suggested that the fast saturation of SPS-Cl failed in superfilling while a gradual increase in the SPS-Cl coverage through competition with initially adsorbed PEG-Cl enabled it. Consequently, superfilling was achievable only in the case of applying the plating potential as soon as the substrate is dipped in an electrolyte to prevent rapid accumulation of SPS-Cl on the surface.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.394-394
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• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.396-396
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• 2012

$TiO_2$ anatase nanotube arrays (NTAs) were grown by electrochemical anodization and followed annealing of Ti foil. Ethylene glycol/$NH_4F$-based organic electrolyte was used for electrolyte solution and using second anodization process to obtain free-standing NTAs. After obtaining NTAs, ITO film was deposited by sputtering process on bottom of NTAs. UV-curable NOA was used for attach free-standing NTAs on flexible plastic substrate (PEN). Solid state electrolyte (spiro-OMeTAD) was coated via spin-coating method on top of attached NTAs. Ag was deposited as a counter electrode. Under AM 1.5 simulated sunlight, optical characteristics of devices were investigated. In order to use flexible polymer substrate, processes have to be conducted at low temperature. In case of $TiO_2$ nano particles (NPs), however, crystallization of NPs at high temperature above $450^{\circ}C$ is required. Because NTAs were conducted high temperature annealing process before NTAs transfer to PEN, it is favorable for using PEN as flexible substrate. Fabricated flexible solid-state DSSCs make possible the preventing of liquid electrolyte corrosion and leakage, various application.

• 한국세라믹학회지
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• 제55권6호
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• pp.562-569
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• 2018

We propose an economic and facile method for the preparation of silica nanoparticles through a two-step process utilizing chlorosilane residues. Mixed chlorosilane residue was alcoholized with absolute ethanol as a first step to form tetraethoxysilane (TEOS). The TEOS was then utilized as a silicon source to synthesize silica nanoparticles in a sol-gel method. The alcoholysis process was designed and optimized utilizing the Taguchi experimental design method and the yield of TEOS was as high as 82.2% under optimal synthetic conditions. Similarly, the Taguchi method was also utilized to study the effects of synthesis factors on the particle size of silica nanoparticles. The results of statistical analysis indicate that the concentration of ammonia has a greater influence on particle size compared to the mass fractions of TEOS and polyethylene glycol (4.6% and 9.7%). The purity of the silica particles synthesized in our experiments is high, but the specific surface area and pore volume are small.

• 한국정밀공학회지
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• 제25권9호
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• pp.32-37
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• 2008

Freestanding hydride vapor phase epitaxy grown GaN(Gallium Nitride) substrates subjected to various polishing methods were characterized for their surface and subsurface conditions, Although CMP(Chemical Mechanical Polishing) is one of the best approaches for reducing scratches and subsurface damages, the removal rate of Ga-polar surface in CMP is insignificant($0.1{\sim}0.3{\mu}m$/hr) as compared with that of N-polar surface, Therefore, conventional MP(Mechanical Polishing) is commonly used in the GaN substrate fabrication process, MP of (0001) surface of GaN has been demonstrated using diamond slurries with different abrasive sizes, Diamond abrasives of size ranging from 30nm to 100nm were dispersed in ethylene glycol solutions and mineral oil solutions, respectively. Significant change in the surface roughness ($R_a$ 0.15nm) and scratch-free surface were obtained by diamond slurry of 30nm in mean abrasive size dispersed in mineral oil solutions. However, MP process introduced subsurface damages confirmed by TEM (Transmission Electronic Microscope) and PL(Photo-Luminescence) analysis.

• 한국환경과학회지
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• 제18권9호
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• pp.953-959
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• 2009

A practical and efficient disposal method for chemical dechlorination of PCBs (polychlorinated biphenyls) in transformer oil was evaluated. The transformer oil containing PCBs was treated by the PEG 600 (polyethylene glycol 600) and potassium hydroxide (KOH) along with different reaction temperatures(25, 50, 100 and $150^{\circ}C$) and times(30, 60, 240 and 480 min). The best disposal efficiency of PCBs in transformer oil was attained under the experimental conditions of PEG 600 (2.5 w/w%)/KOH (2.5 w/w%)/$150^{\circ}C$/4 hrs, showing completely removal of all PCBs containing 3-9 chlorines on two rings of biphenyl. In studying the reaction of PEG/KOH with PCBs, it confirmed that the process led to less chlorinated PCBs through a stepwise process with the successive elimination of chlorines.

• Mycobiology
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• 제29권1호
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• pp.15-18
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• 2001

Protoplast fusion is a useful technique for establishing fungal hybrids to overcome the natural barriers. The ultrastructure of protoplast and its fusion process were observed using a scanning electron microscopy(SEM) and a transmission electron microscopy(TEM). The protoplasts were variable in size from $0.5{\sim}15{\mu}m$ in diameter, and the mean diameter was about $3{\sim}5{\mu}m$. It was impossible to discriminate protoplasts of Lentinula edodes from protoplasts of Coriolus versicolor by size and surface structure. Big aggregates of the dehydrated protoplasts were observed, after polyethylene glycol 4000 treatment. Nucleus, mitochondria, lipid granules and various vesicles having granules were scattered in the cytoplasm. The vesicles were heterogeneous in size and vary from one protoplast to another. The fused membrane layer of the two protoplasts was observed. Time protoplast membrane contact and reorganization of membrane components were essential condition for protoplast fusion. Transmission electron micrograph showed fused protoplasts and flattening of the cells in the area of the membrane contact. We hope that our electron microscopic observations provide some insights into the understanding of the fusion process of protoplast in fungi.

• 한국표면공학회지
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• 제46권4호
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• pp.153-157
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• 2013

The defect like the void or seam is frequently generated in the PCB (Printed Circuit Board) Via-Filling plating inside via hole. The organic additives including the accelerating agent, inhibitor, leveler, and etc. are needed for the copper Via-Filling plating without this defect for the plating bath. However, the decomposition of the organic additive reduces the lifetime of the plating bath during the plating process, or it becomes the factor reducing the reliability of the Via-Filling. In this paper, the interaction of each organic additives and the decomposition of additive were discussed. As to the accelerating agent, the bis (3-sulfopropyl) disulfide (SPS) and leveler the Janus Green B (JGB) and inhibitor used the polyethlylene glycol 8000 (PEG). The research on the interaction of the organic additives and decomposition implemented in the galvanostat method. The additive decomposition time was confirmed in the plating process from 0 Ah/l (AmpereHour/ liter) to 100 Ah/l with the potential change.

• 한국분말재료학회지
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• 제19권1호
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• pp.60-66
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• 2012

In this study, Platinum(Pt) nanoparticles were synthesized by using polyol process which is one of the liquid phase reduction methods. Dihydrogen hexachloroplatinate (IV) hexahydrate $(H_2PtCl_6{\cdot}6H_2O)$, as a precursor, was dissolved in ethylene glycol and silver nitrate ($AgNO_3$) was added as metal salt for shape control of Pt particle. Also, polyvinylpyrrolidone (PVP), as capping agent, was added to reduce the size of particle and to separate the particles. The size of Pt nanoparticles was evaluated particle size analyzer (PSA). The size and morphology of Pt nanoparticles were observed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM). Synthesized Pt nanoparticles were studied with varying time and temperature of polyol process. Pt nanoparticles have been successfully synthesized with controlled sizes in the range 5-10 and 20-40 nm with cube and multiple-cube shapes.