• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2001년도 제21회 학술발표회 초록집
• /
• pp.92-92
• /
• 2001

• Bulletin of the Korean Chemical Society
• /
• 제25권6호
• /
• pp.786-790
• /
• 2004

2-Aminoethanethiol (aet) has been used to make self-assembled monolayer (SAMs) on gold electrodes, which are subsequently modified with 3,4-dihydroxy phenylalanine (dpa). Such modified electrodes having various types of Au/aet-dpa were employed in the electrocatalytic oxidation of NADH. The purpose of this study to characterize the responses of such modified electrodes in terms of the immobilization procedure, pH of the solution and applied potential. The reaction of the surface immobilized dpa with NADH was studied using the rotating disk electrode technique and a value of $2.2{\times}10^4M^{-1}s^{-1}$ was obtained for the second-order rate constant in 0.1 M Tris/$NO_3^-$buffer (pH=8.0). The hydration behavior of the films was characterized by quartz crystal microbalance. When used as a NADH sensor, the Au/aet-dpa electrode exhibited good sensitivity and an excellent correlation (r ${\geq}$ 0.99) for NADH concentration which extended to $3.8{\times}10^{-3}$ M.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2002년도 동계연구발표회 논문개요집
• /
• pp.192-193
• /
• 2002

비자성 금속에 자성 불순물이 첨가되었을 경우 비자성 전이금속의 전도전자들이 불순물에서 멀어지면서 감쇠 진동하는 형태로 스핀분극 된다는 사실은 매우 잘 알려져 있으며, 그 진동주기는 Fermi 파동벡터 크기(k$_{F}$ )의 역수의 절반이다[1]. 비자성 금속 내의 자성 불순물사이의 상호작용은 전도성 전자의 감쇠 진동하는 스핀 분극에 바탕을 둔 RKKY 교환 상호작용[2]으로 잘 기술된다. (중략)

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.475-478
• /
• 2000

Maxwell displacement current(MDC) was generated when the area per molecule was about 140${\AA}$$^2$and 100${\AA}$$^2$. MDC were investigated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. The absorption spectra of polyamic acid containing p-methoxyazobenzene in a mixture of N,N-dimethylacetamide(DMAc) and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. The precursor LB film was heated in a vacuum dry oven at 120$^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.317-319
• /
• 2000

We fabricated the QCM with Langmuir-Blodgett(LB) film deposited at the different subphase pH and investigated the resonant frequency response by the injection of organic gas response. In the $\pi$-A isotherms, the monolayer on the air/water interface had different limiting area per molecule and showed more condensed status as increasing the subphase pH. When palmitic acid LB film was deposited on the QCM, the resonant frequency shift was proportional to the deposited layer and had more resonant frequency shift in the case of the higher pH range as expected. In the resonant frequency for the injection of organic gas, it has been improved in the case of LB film fabricated at the lower subphase pH range and dependant upon the molecular weight of organic gas.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 C
• /
• pp.1583-1585
• /
• 2003

Maxwell displacement current(MDC) measuring technique has been employed to study the dielectric property of Langmuir-films. A method for determining the dielectric relaxation time ${\tau}$ of floating monolayers on the water surface is presented. MDC flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time ${\tau}$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayer compression speed ${\alpha}$ and the molecular area Am. Compression speed ${\alpha}$ was about 30, 40, 50mm/min.

• Tribology and Lubricants
• /
• 제4권2호
• /
• pp.44-51
• /
• 1988

Titanium carbide(TiC), Titanium nitride(TiN), and Titanium carbonnitride(Ti(C,N)) films were deposited on $Si_3N_4$-TiC composite cutting tools by chemical vapor deposition(CVD) using $TiCl_4-CH_4-H_2$, $TiCl_4-N_2-H_2$, and $TiCl_4-CH_4-N_2-H_2$ gas mixtures, respectively. The experimental results indicate that TiC coatings compared with TiN coatings on $Si_3N_4$ -TiC ceramic have an improved microstructural property, good thermal shock resistance, and good interfacial bonding. However TiN coatings compared with TiC coatings have a low friction coefficient with steel and good chemical stability. It is found by cutting test that coated insert compared with $Si_3N_4$-TiC ceramic have a superior flank and crater wear resistance. And multilayer coating compared with monolayer coating shows a improved wear resistance.

• Bulletin of the Korean Chemical Society
• /
• 제16권6호
• /
• pp.493-498
• /
• 1995

Ultrathin networks of itaconic acid copolymers and poly(allylamine) were produced by a Langmuir-Blodgett (LB) technique employing a double-chain amine as a monolayer template which was subsequently removed by extraction after thermal crosslinking. Itaconic acid copolymers used were copoly (itaconic acid-ethyl vinyl ether) and copoly (itaconic acid-n-butyl vinyl ether). The polyion-complexed monolayers of three components consisting of template amine, itaconic acid copolymer and poly (allylamine) were formed at the air-water interface. The Langmuir film properties have been studied by the surface pressure-area isotherm and fluorescence microscopy. The monolayers were transferred on solid substrates and were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). Two-dimensional polymer networks were formed through imide or amide linkages by heat treatment under vacuum. The heat-treated films were extracted with chloroform after immersion in aq. sodium chloride to remove the template amines. SEM observation of a LB film on a porous fluorocarbon membrane filter with pore diameter of 0.1 μm showed covering of the pores by six layers in the polyion complex state.

• 한국포장학회지
• /
• 제5권1호
• /
• pp.6-12
• /
• 1999

본 실험은 라면 스프 포장재에 대한 가식성 필름의 응용성을 조사하였다. 기본 실험으로서는 라면 스프의 등온흡습곡선 및 BET 단분자막 수분함량을 조사하였으며, 응용성 실험으로서는 가식성 필름의 인장강도, 신장률, 수분 투과도 및 용해도를 대하여 조사하였다. 가식성 필름으로서는 methylcellulose, sodium caseinate 및 K-carrageenan을 사용하였으며, 가소제로서는 glycerol과 polyethylene glycol (MW 400)을 사용하였다. 인장강도의 경우, methylcellulose 필름의 수치가 68.56 MPa로 가장 크게 나타났으며, sodium caseinate 필름이 가장 낮은 수치인 7.11 MPa로 나타났다. 신장률에 대한 실험 결과, sodium caseinate 필름이 가장 높은 수치인 115.41 %를 나타냈으며, methylcellulose 및 K-carrageenan 필름은 각각 23.79% 및 0.60%로 나타났다. 상대습도 50% - 70%사이에서 methylcellulose와 sodium caseinate 및 K-carrageenan 필름의 측정된 수분 투과도 값의 범위는 각각 $0.25-0.38ng\;m/m^2{\cdot}sec{\cdot}Pa$와 $0.62-0.84ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa$ 및 $0.31-0.55ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa$로 나타났다. 가식성 필름의 용해도에 대해서는 sodium caseinate film의 경우 뜨거운 물에 대한 높은 용해성을 나타내어 5초 이내에 이 필름은 물에 용해되었으며, K-carrageenan film은 높은 팽윤율을 나타내어 150초 이후에 필름의 붕괴 현상이 일어났다. Methylcellulose film의 경우는 물에 대한 용해도가 떨어지는 것으로 나타났다.

• 한국응용과학기술학회지
• /
• 제13권1호
• /
• pp.75-85
• /
• 1996

The absorption spectra of synthesis of long chain fatty acid containing azobenzene start from p-(p'-hydroxy phenyl azo)-benzoic acid was investigated by ultraviolet spectrophotometery in chloroform solvent at the various temperature. In addition, The pressure-area of the water-air interface was obtained and the LB film was fabricated onto a quartz slide and quartz crystal by conventional Langmuir-Blodgett(LB) method. The UV absorption spectra of Langmuir-Blodgett(LB) film on quartz slide and spectrum of monolayer formed on quartz crystal have been measured. Long chain fatty acid containing azobenzene are induced phtoisomerization by the application of u. v. and visible light irradiation alternatively the reversibility of phtoisomerization was more clear difference when the number of $C_{n}$ increased but, not so good at $C_{14}-azo$. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_{n}$ increased. A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were induced by application of UV and visible light irradiation alternatively. So the LB film of long chain fatty acid containing azobenzene has possibility to being applied to functional molecular devices such as photomemory and light switching.