• Journal of the Korean Applied Science and Technology
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• v.20 no.2
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• pp.148-153
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• 2003

Electron transfer through an Langmuir-Blodgett(LB) monolayer film sandwiched between metal electrodes. We used an eicosanoic acid material and the material was very famous as a thin film insulating material. Eicosanoic acid monolayer was deposited by Langmuir-Blodgett(LB) technique and a subphase was a $CdCl_2$ solution as a 2${\times}10^{-4}$ mol/L. Also we used a bottom electrode as an Al/$Al_2O_3$ and a top electrode as a Al and Ti/Al. Here, the $Al_2O_3$ on the bottom electrode was deposited by thermal evaporation method. The $Al_2O_3$ layer was acted on a tunneling barrier and insulating layer in tunnel diode. It was found that the proper transfer surface pressure for film deposition was 25 mN/m and the limiting area per molecule was about 24 ${\AA}^2$/molecule. When the positive and negative bias applied to the molecular device, the behavior shows that a tunnel switching characteristics. This result were analyzed regarding various mechanisms.

• Resources Recycling
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• v.8 no.1
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• pp.37-43
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• 1999

Studies have been conducted for the purpose of using manganese nodule and residue remained after extracting valuable metals [mm it as the adsorbent of cadmium wastewater. The study observed the adsorption percentage according to initial cadmium concentration and interpreted each adsorption systems by applying the Freundlich, Langmuir, and Temkin isotherms. The adsorption amounts increased as the initial concentration at cadmium ion increased, whereas the adsorption percentage decreased. Linearity was shown when applied to the Freundlich and Langmuir isotherms. The k value which evaluates the adsorption capacity of adsorbent in Freundlich isotherm, turned out to be 11.72, the highest in case of manganese nodule. The Xm value, the maximum adsorption amount of the adsorbate that adsorbs as a monolayer in Langmuir isotherm of manganese nodule, was estimated as 0.16, representing higher value compared with those of leached residue, leached residue-raw manganese nodule mixture, and activated carbon.

• Electrical & Electronic Materials
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• v.6 no.3
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• pp.228-231
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• 1993

Langmuir-Blodgett(LB) 초박막 MIM구조의 소자에서 직류전압이 발생된다는 것은 이미 잘 알려져 있다. 발생전압의 원인은 LB막과 전극사이의 어떤 화학반응에 의한 것으로 보고되었다. 본 논문에서는 1986년에 제작되어 공기중에 방치된 LB 초박막 시료를 대상으로 실험한 결과, 제작 당시와 동일한 크기의 전압이 발생하고 있음을 확인할 수 있었다. 이때 LB막과 전극의 두께는 각각 20~30.angs. 및 2000.angs.정도이었다.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.145-148
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• 1989

Plasma diagnostics using Langmuir Probe is of wide application because of its simplicity in measurement of electron temperatures and densities. Current methods using simple circuit and analog meters, however, have troubles when they are applied to time-varying or thermal plasmas. To overcome these problems and expand the area of applicability, we have designed fast electronic voltage sweeping circuit in which we can detect digital data. Diagnostics using our digital Langmuir Probe is performed in various kinds of plasmas and the results are shown. Our method can be applied to measuring electron temperature and density of high temperature or time-varying plasmas. And we expect further knowledge of each state of plasma.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.110-115
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• 2006

We conducted a sensitivity analysis of the simulated moving bed (SMB) chromatography with the case model of the separation of two amino acids phenylalanine and tryptophan. We consider a four-zone SMB chromatography where the triangle theory is used to determine the operating conditions. Competitive Langmuir isotherm model was used to determine the adsorption isotherm. The finite difference method is used to solve nonlinear partial differential equation (PDE) systems numerically. We examined the effects of alterations in the operating conditions(feed-extract, feed-raffinate, eluent-extract, eluent-raffinate, recycle, and switching time) and the adsorption isotherm parameters (Langmuir isotherm parameters a and b) on SMB efficiency. The variation range of operating conditions and Langmuir isotherm a was between -50 and 50% of original value and the variation range of the Langmuir isotherm b was between $2.25^{-5}$ and $2.25^5$ times of original value.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.151-155
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• 1994

Polyamic acid alkylamine (N, N-dimethylhexadecylamine)(PAAS)염을 합성하여 그 합성여부를 확인하였으며 PAAS염의 Langmuir막의 ${\pi}-A$ 등온선 및 표면 전위 특성 등을 조사 하였다. Langmuir-Blodgett법에 의하여 PAAS염의 LB막을 여러종류의 기관에 누적하였으며 누적여부를 자외선 흡수 스펙트럼 및 적외선 투과 스펙트럼을 이용하여 조사하였다. 그리고 PAAS LB막을 열처리에 의하여 이미드(imide)화시켜 폴리이미드 LB막을 제조하였으며 그 이미드화 여부를 자외선 및 적외선 스펙트럼을 이용하여 조사하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.81-88
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• 2005

The Langmuir monolayers of polyamic acid salts with three kinds of alkyl chains have been investigated by means of conventional $\pi$-A isotherms and second harmonic generation measurements proposed in this paper. The surface molecular density dependence of second harmonic intensity clearly shows the region of aggregation while corresponding $\pi$-A isotherm doesn't show any changes in the surface morphology at the same region. The surface morphology analysis based on the second harmonic measurement was consistent with the Brewster angle microscope measurement results.

• Korean Journal of Materials Research
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• v.10 no.8
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• pp.564-568
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• 2000

Langmuir-Blodgett(LB) 법은 미래의 분자전자소자를 위한 가장 유력한 수단이며, 이러한 분자박막 소자는 그 성질이 분자는 배향에 영향을 박데 되므로 현재 새로운 물질을 이용하여 분자전자소자의 제작에 있어 관심을 모으고 있다. 본 연구에서는 (N-docosyl quinolinium)-TCNQ(1:2) 전하 이동 착물 LB 막의 분자 배향을 UV/vis 편광흡수 스펙트럼과 FT-IR transmission 및 reflection-absorption 스펙트럼의 흡수강도를 비교하여 정량적으로 평가하였다. 그 결과 TCNQ의 transition dipole moment의 각은 약 56~58。 였으며, 알킬 고리의 경사각은 약 11.1~13。였다. 제작된 Z-형 LB 막의 표면은 고압에서 중앙 높이 차가 3~4$\AA$으로 평탄하였다.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.558-563
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• 2014

Sum-frequency generation spectra of a Langmuir monolayer on water surface at varying surface areas were studied with two-dimensional correlation analysis. Upon enlarging the area/molecule of the Langmuir monolayer, the sum-frequency spectra changed reflecting the conformation change of the alkyl chains of the molecules in the monolayer. These changes stood out more clearly by employing two-dimensional correlation analysis of the above sum-frequency spectra. Features not very pronounced in the original spectra such as closely-spaced spectral bands can also be easily distinguished in the two-dimensional correlation spectra.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1609-1611
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• 1994

In ECR and helicon reactors for plasma processing, a high density plasma is generated in a source region which is connected to a diffusion region where the processing takes place. Large density and potential gradients can develop at the orifice of the source which drive ion currents into the diffusion region. The average ion velocity may become the order of the sound velocity. Measurements of the ion saturation current to a Langmuir probe are used as a standard method of determining the plasma density in laboratory discharges. However, the analysis becomes difficult in a steaming plasma. We have used the HAMLET plasma simulator to simulate the ion flow to a large langmuir probe in an ECR plasma. The collection surface was aligned with the Held upstream, normal to the field, and downstream. ion trajectories through the electric and magnetic fields were calculated including ion-neutral collisions. We examines the ratio of ion current density to plasma density as a function of magnetic field and pressure.