• 한국광학회지
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• 제15권6호
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• pp.531-538
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• 2004

균일한 표면에서 일어나는 가파른 계단형식의 흡착에 대한 연구는 이차원 현상에 대한 이해를 한층 높일 수 있다. 이를 위해 편광변조 타원해석법을 이용한 흡착측정장치를 제작하였다. 타원해석법 신호가 흡착막 형성의 과정을 원자층 이하 (∼0.3 $\AA$)로 매우 예민하게 측정할 수 있음을 확인할 수 있었다. HOPG (highly oriented pyrolytic graphite) 표면에서의 아르곤의 흡착 다층막을 측정한 결과, 34.04 K에서는 수천여개의 흡착층이 형성되어 완전 젖음이 일어남을 관찰할 수 있었다. 또한 67.05 K에서는 선명한 계단 형식으로 일어나는 9개의 흡착과 탈착을 확인할 수 있었다. 이에서 얻은 등온흡착곡선들은 많은 열역학적 상태에 관한 정보, 표면과 기체의 결합에너지에 대한 정보, 흡착막의 구조전이에 대한 정보 등을 줄 수 있을 것이다.

• Transactions on Electrical and Electronic Materials
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• 제7권3호
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• pp.112-117
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• 2006

In this paper we present that the effects of polymer adsorption on stabilities and CMP performance of ceria abrasive particles. Characterization of ceria abrasive particles in the presence of poly(vinyl pyrrolidone) (PVP) was performed by the measurements of adsorbed amounts of PVP, average sizes, and the back scattering intensities of the ceria abrasive particles as functions of PVP molecular weight and PVP concentration. The ceria abrasive particles in the presence of PVP were used to polish $SiO_2\;and\;Si_3N_4$ films deposited on Si wafers in order to understand the effect of PVP adsorption on chemical mechanical polishing (CMP) performance, together with ceria abrasive particles without PVP. Adsorption of PVP on the ceria abrasive particles enhanced the stability of ceria abrasive particles due to steric stabilization of the thick adsorbed layer of PVP. Removal rates of the deposited $SiO_2\;and\;Si_3N_4$ films by the ceria abrasive particles in the presence of PVP were much lower than those in the absence of PVP and their magnitudes were decreased with an increase in the concentration of free PVP chains in the dispersion media. This suggests that the CMP performance in the presence of PVP could be mainly controlled by the hydrodynamic interactions between the adsorbed PVP chains and the free ones. Moreover, the molecular weight dependence of PVP on the removal rates of the deposited films was hardly observed. On the other hand, high removal rate selectivity between the deposited films in the presence of PVP was not observed.

• 공업화학
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• 제24권1호
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• pp.24-30
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• 2013

Quartz crystal microbalance with dissipation monitoring (QCM-D)을 활용하여 양이온성으로 치환된 전분 및 올리고당의 흡착특성을 연구하였다. 전 합성계열의 흡착량은 양이온 계면활성제($C_{12{\sim}16}$ trimethylammonium bromide) 대비 높은 흡착량을 보였으며, 치환비율 및 분자량에 따른 특별한 흡착량의 경향성은 관찰되지 않았다. 반면에, 점탄성(viscoelasticity) 측면에서는 분자량이 증가될수록 흡착층의 강도가 증가되는 경향이 관찰되었다. 흡착 및 탈착실험에서 단분자인 양이온성 계면활성제의 흡착량의 차이는 약 4~9배에 수준의 큰 차이가 발생되었으나 양성치환된 전분계열에서는 0~50% 수준의 작은 차이를 나타내었다. 또한, 탈착단계 이후 흡착단계에 비해 양이온 계면활성제에서는 흡착층의 강도 (rigidity)가 감소된 반면 양성치환된 전분계열에서는 강도가 증가되는 상반된 경향이 관찰되었다.

• Corrosion Science and Technology
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• 제16권1호
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• pp.31-37
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• 2017

A synergistic effect was observed in the combination of nitrite and ethanolamines. Ethanolamine is one of the representative organic corrosion inhibitors and can be categorized as adsorption type. However, nitrosamines can form when amines mix with sodium nitrite. Since nitrosamine is a carcinogen, the co-addition of nitrite and ethanolamine will be not practical, and thus, a non-toxic combination of inhibitors shall be needed. In order to maximize the effect of monoethanolamine, we focused on the addition of molybdate. Molybdate has been used to alternate the addition of chromate, but it showed insufficient oxidizing power relative to corrosion inhibitors. This work evaluated the synergistic effect of the co-addition of molybdate and monoethanolamine, and its corrosion mechanism was elucidated. A high concentration of molybdate or monoethanolamine was needed to inhibit the corrosion of ductile cast iron in tap water, but in the case of the co-addition of molybdate and monoethanolamine, a synergistic effect was observed. This synergistic effect could be attributed to the molybdate that partly oxidizes the metallic surface and the monoethanolamine that is simultaneously adsorbed on the graphite surface. This adsorbed layer then acts as the barrier layer that mitigates galvanic corrosion between the graphite and the matrix.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4281-4285
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• 2011

We introduced a promising patterned substrate by using a microcontact printing method that can be used for SERS immunoassays based on antigen-antibody binding. SERS spectrum of the Raman reporter with antibody, which is rhodamine 6G (R6G) adsorbed on colloidal gold nanoparticles, was observed only for the surfaces in which prostate-specific antigen (PSA) is present on the substrate that is attached to an immobilized layer of antibody on the gold nanoparticles layer of the patterned substrate. Raman mapping images clearly showed that the antibodies on the Raman reporter were successfully and selectively conjugated with the antigen on the patterned substrate. This method could be potentially extended to multi-protein detections and ultrasensitive biosensors.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2419-2422
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• 2014

The syntheses and crystal structures of a three-dimensional (3D) coordination network $[Zn_4(2-mBIM)_5-(C_2H_6NCOO)(HCOO)({\mu}-OH)]{\cdot}DMF$ ($1{\cdot}$DMF; 2-mBIM = 2-methylbenzimidazolate) and a two-dimensional (2D) layer $[Zn_2(2-mBIM)_3(HCOO)(H_2O)]{\cdot}DMF$ ($2{\cdot}DMF$) are reported. Different structures were produced depending on the ratio of reactants. Structurally, 1 illustrates the formation of a unique framework based on a 2-mBIM bridge with the side group on an imidazole ring, while 2 possesses a honeycomb layer built up purely from imidazolates. For gas sorption, $CO_2$ is adsorbed on the activated phase of 1 but $N_2$ is not taken up.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.79-79
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• 2003

SHG (Second harmonic generation) can be used to probe the surface of centrosymmetric particles suspended in bulk isotropic solution, because it is forbidden in centrosymmetric media under the dipole approximation. Using this technique, we can study the transport dynamics of small organic dye molecules across liposome bilayers. Because molecules adsorbed on the outer layer are in opposite direction with that on the inner layer by symmetry, the SH field is proportional to the difference between the number density of dye molecules on both sides of the bilayer, and the time dependence of the SH intensity is related to the time constant of the molecular transportation of dye molecules across liposome bilayers.

• Korea-Australia Rheology Journal
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• 제15권1호
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• pp.1-7
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• 2003

A new method is introduced to build up organic/organic multilayer films composed of cationic poly(allylamine hydrochloride) (PAH) and negatively charged poly (sodium 4-styrenesulfonate) (PSS) using the spinning process. The adsorption process is governed by both the viscous force induced by fast solvent elimination and the electrostatic interaction between oppositely charged species. On the other hand, the centrifugal and air shear forces applied by the spinning process significantly enhances desorption of weakly bound polyelectrolyte chains and also induce the planarization of the adsorbed polyelectrolyte layer. The film thickness per bilayer adsorbed by the conventional dipping process and the spinning process was found to be about 4 ${\AA}$ and 24 ${\AA}$, respectively. The surface of the multilayer films prepared with the spinning process is quite homogeneous and smooth. Also, a new approach to create multilayer ultrathin films with well-defined micropatterns in a short process time is Introduced. To achieve such micropatterns with high line resolution in organic multilayer films, microfluidic channels were combined with the convective self-assembly process employing both hydrogen bonding and electrostatic intermolecular interactions. The channels were initially filled with polymer solution by capillary pressure and the residual solution was then removed by the .spinning process.

• Carbon letters
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• 제10권4호
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• pp.305-313
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• 2009

In this study, the adsorption of toxic pollutants onto cetyltrimethylammonium kaolin (CTAB-Kaolin) is investigated. The organo-kaolin is synthesized by exchanging cetyltrimethylammonium cations (CTAB) with inorganic ions on the surface of kaolin. The chemical analysis, the structural and textural properties of kaolin and CTAB-kaolin were investigated using elemental analysis, FTIR, SEM and adsorption of nitrogen at $-196^{\circ}C$. The kinetic adsorption and adsorption capacity of the organo-kaolin towards o-xylene, phenol and Cu(II) ion from aqueous solution was investigated. The kinetic adsorption data of o-xylene, phenol and Cu(II) are in agreement with a second order model. The equilibrium adsorption data were found to fit Langmuir equation. The uptake of o-xylene and phenol from their aqueous solution by kaolin, CTAB-kaolin and activated carbon proceed via physisorption. The removal of Cu(II) ion from water depends on the surface properties of the adsorbent. Onto kaolin, the Cu(II) ions are adsorbed through cation exchange with $Na^+$. For CTAB-kaolin, Cu(II) ions are mainly adsorbed via electrostatic attraction with the counter ions in the electric double layer ($Br^-$), via ion pairing, Cu(II) ions removal by the activated carbon is probably related to the carbon-oxygen groups particularly those of acid type. The adsorption capacities of CTAB-kaolin for the investigated adsorbates are considerably higher compared with those of unmodified kaolin. However, the adsorption capacities of the activated carbons are by far higher than those determined for CTAB-kaolin.

• 한국미생물·생명공학회지
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• 제18권3호
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• pp.233-238
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• 1990

The mechanism of intracellular accumulation of cadmium in a cadmium-ion tolerant yeast, Hansenula ammala B-7, which is an extreme cadmium tolerant strain and has the ability to take up a large amount of cadmium was investigated. The amounts of cadmium taken up by the scalded yeast cells were 2 to 3 times more than the value of the living cells. The living Hansenula anomala B-7 cells adsorbed 74% of cadmium taken up onto the other layer of the cells and 26% of it accumulated inside the cells. But the scalded cells adsorbed 98.3% of cadmium taken up and accumulated 1.7% of it inside the cells. A cadmium uptake and its accumulation were accelerated up to 162.3% and 275.4% by Triton X-100 in the living cells, respectively. Whereas in the scalded cell cadmium uptake was not affected by Triton X-100. Furthermore the cadmium uptake and its accumulation were strongly inhibited by metabolic inhibitors like 2,4-dinitrophenol, sodium azide and potassium cyanide in the living cells, but in the scalded cells cadmium uptake was not affected by metabolic inhibitors. These results suggested that the intracellular accumulation of cadmium by the cadmium-tolerant Hansenula anomala B-7 cells was apparently dependent of biological activity, and also gave evidence of the existance of energy-dependent system.