• 한국기계가공학회지
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• 제13권1호
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• pp.52-58
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• 2014

This study consists of two parts. The first discusses the development of a single production forming machine which was reported in earlier papers. The second outlines the development of a multi-production forming machine, which consists primarily of a film feeding unit, an unwinding unit, and a heating block unit. The heating block unit of the multi-production forming machine has 30 members per die. An analysis of the stress deformation and temperature deviation of this machine is carried out using ANSYS Workbench and CFX-11 under the design conditions. According to this analysis, the maximum deflection in the Z-direction is $0.05104{\mu}m$ and the maximum temperature deviation is $0.7^{\circ}C$ when the temperature of the heating block unit is $175^{\circ}C$. It was also found that these values are structurally safe. The advantage of the developed multi-production forming machine is demonstrated to be in its offering of a proper voice test.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.112-112
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• 2011

The interaction of water molecules with solid surfaces has been a subject of considerable interests, due to its importance in the fields from atmospheric and environmental phenomena to biology, catalysis and electrochemistry [1,2]. Among various kinds of surfaces, a lot of theoretical and experimental studies have been performed regarding water on MgO(100), however, to date, there has been no direct observation of water molecules on MgO by scanning tunneling microscope (STM) as compared with those on metal surface. Here, we will present the direct observation and manipulation of single water molecules on ultrathin MgO(100) films using low-temperature scanning tunneling microscope (LT-STM) [3]. Our results rationalize the previous theoretical predictions of isolated water molecules on MgO including the optimum adsorption sites and non-dissociative adsorption of water. Moreover, we were able to dissociate a water molecule by exciting the vibrational mode of water, which is unattainable on metal surfaces. The enhanced residual time of tunneling electrons in molecules on the insulating film is responsible for this unique pathway toward dissociation of water.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1649-1656
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• 2010

Internal reorganization energy due to the structural relaxation in hole or electron hopping mechanism is one of the measurements of key indices in designing an organic thin film transistor (OTFT) for flexible display devices. In this study, the reorganization energies of dicyanoanthracenes for the hole and electron transfer were estimated by adiabatic potential energy surface and normal mode analysis method in order to examine the effect on the energies for the positional variation of the cyano substituents in the anthracene as a protocol of acenes to design an organic field effect transistor. The reorganization energy for the hole transfer was reduced considerably upon cyanation of anthracene, especially at the 9,10-positions of anthracene, and the origin of the reduction was interpreted in terms of understanding the coupling of vibrational modes to the hole transfer.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.470-474
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• 2013

Surfaced-enhanced Raman scattering (SERS) of 4,4'-biphenyldithiol (BPDT) has been investigated at a silver island film. Ordinary Raman (OR) spectra of neat sample in solid state and in basic solution have also been taken for comparison. The spectral feature in the SERS spectrum was similar to that for the OR spectrum in basic solution, except for the broadening of ring stretching bands indicative of the presence of surface-phenyl ring $\pi$ interaction. In contrast, only absence of the C-H stretching band with very small Raman scattering cross-section seemed not pertinent in judging the definitive orientation of molecule. The observed vibrational bands in the SERS spectrum have been assigned by referring to the normal modes and wavenumbers from density functional theory (DFT) calculations of the simple model as 4,4'-biphenyldithiolates bound to two Ag atoms at the both ends. Excellent agreement between the experimental and the calculated results was achieved, which is remarkable considering the level of theory applied.

• E2M - 전기 전자와 첨단 소재
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• 제7권6호
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• pp.473-480
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• 1994

The electron tunnel effect in polvimide LB films sandwiched between metal electrodes has been investigated in the present work by a study of both the elastic and inelastic tunneling components. By the results of elastic tunneling experiments in Au/Pl/Au tunneling junction, we can judge the height and thickness of tunnel barrier. The inelastic current in Inelastic Electron Tunneling Spectroscopy(IETS) is due to the interaction of the tunneling electron with the vibrational modes of the molecular species in the barrier. Measurements are done on Au/PI/Pb tunneling junctions. The spectra obtained are the second derivatives of the current-voltage characteristics of these junctions : specifically, d$^{2}$1/dV$^{2}$ as a function of voltage V. Because the energies measured by IETS can be directly compared to those measured by infrared and Raman spectroscopy, IR-RAS spectroscopy also measured for reference.

• 반도체디스플레이기술학회지
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• 제8권3호
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• pp.19-23
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• 2009

We have studied dielectric characteristics of low-k interlayer dielectric materials was fabricated by plasma enhanced chemical vapor deposition (PECVD). BTMSM precursor was introduced with the flow rates from 24 sccm to 32 sccm by 2 sccm step in the constant flow rate of 60 sccm $O_2$. Then, SiOCH thin film deposited at room temperature was annealed at temperature of $400^{\circ}C$ and $500^{\circ}C$ for 30 minutes in vacuum. The vibrational groups of SiOCH thin films were analyzed by FT/IR absorption lines, and the dielectric constant of the low-k SiOCH thin films were obtained by measuring C-V characteristic curves. With the result that FTIR analysis, as BTMSM flow rate increase, relative carbon content of SiOCH thin film increased from 29.5% to 32.2%, and increased by 32.8% in 26 sccm specimen after $500^{\circ}C$ annealing. Dielectric constant was lowest by 2.32 in 26 sccm specimen, and decreased more by 2.05 after $500^{\circ}C$ annealing. Also, leakage current is lowest by $8.7{\times}10^{-9}A/cm^2$ in this specimen. In the result, shift phenomenon of chemical bond appeared in SiOCH thin film that BTMSM flow rate is deposited by 26 sccms, and relative carbon content was highest in this specimen and dielectric constant also was lowest value

• 한국가구학회지
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• 제11권1호
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• pp.45-51
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• 2000

일반적으로 도막의 강성은 목재의 강성에 비해 낮으므로 도장된 소재의 강성이 백골재에 비해 낮아질 것으로 짐작할 수 있으므로 본 연구에서 는 바이올린용 소재 인 유럽산 가문비 나무와 단풍나무에 투명 래커와 전통옻칠을 도포한 후, 진동모드를 해석하고 공진주파수를 비교함으로써 수종별 도료 종류에 따른 음향특성의 변화양상을 분석하고자 하였다. 분석결과, 도장전후의 기본진동모드는 동일하였고 양 수종 공히 도료의 종류에 관계없이 도장재의 공진주파수의 감소가 확인되었으며 가문비나무의 경우, 모드가 증가할수록 주파수 감소폭이 증가하였으나 옻칠이 투명래커에 비해 그 감소폭이 적었다. 단풍나무의 경우에도 상위 모드에서 더 큰 주파수 감소를 나타냈지만 옻칠과 투명래커의 주파수 감소폭이 일정치 않았다.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.47-52
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• 2009

We studied the electrical characteristics of low-k SiOCH interlayer dielectric(ILD) films fabricated by plasma enhanced chemical vapor deposition (PECVD). BTMSM precursor was evaporated and introduced with the flow rates from 16 sccm to 25 sccm by 1 sccm step with the constant flow rate of 60 sccm $O_2$ in process chamber. The vibrational groups of SiOCH thin films were analyzed by FT!IR absorption lines, and the dielectric constant of the low-k SiOCH thin films were obtained by measuring C-V characteristic curves. The heat treatment on SiOCH thin films reduced the FTIR absorption intensity of the Si-O-$CH_3$ bonding group and Si-$CH_3$ bonding group but increased the intensity of Si-O-Si(C) bonding group. The SiOCH ILD films could have low dielectric constant $k\;{\simeq}\;2$ and also be reduced further by decreasing the $CH_3$ group density and increasing Si-O-Si(C) group density through annealing process.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1213-1219
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• 2012

The reorganization energy and the spectroscopic properties of 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'- yl)naphthalene (DH-TNT) and 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'-yl)anthracene (DH-TAT), which are composed of an acene unit and alkylated thienothiophene on both sides, as organic materials for display devices were calculated and the results were compared with experimental values. The lower reorganization energy of the DH-TAT over the DH-TNT calculated by the density functional theory is attributed to a smaller vibrational distortion because of the heavier building block of DH-TAT, and it shows a good field effect performance over the DH-TNT. The calculated spectra and the other spectroscopic characteristic of the compounds are well consistent with those of observed results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.636-636
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• 2013

Since first discovery of strong Raman spectrum of molecules adsorbed on rough noble metal, surface enhanced Raman scattering (SERS) has been widely used for detection of molecules with low concentration. Surface plasmons at noble metal can enhance Raman spectrum and using Au nanostructures as substrates of SERS has advantages due to it has chemical stability and biocompatibility. However, the photoluminescence (PL) background from Au remains a problem because of obtaining molecular vibration information. Recently, graphene, two-dimensional atomic layer of carbon atoms, is also well known as PL quenchers for electronic and vibrational excitation. In this study, we observed SERS of single layer graphene on or under monolayer of Au nanoparticles (NPs). Single layer graphene is grown by chemical vapor deposition and transferred onto or under the monolayer of Au NPs by using PMMA transfer method. Monolayer of Au NPs prepared using Langmuir-Blodgett method on or under graphene surface provides closed and well-packed monolayer of Au NPs. Scanning electron microscopy (SEM) and Raman spectroscopy (WItec, 532 nm) were performed in order to confirm effects of Au NPs on enhanced Raman spectrum. Highly enhanced Raman signal of graphene by Au NPs were observed due to many hot-spots at gap of closed well-packed Au NPs. The results showed that single layer graphene provides larger SERS effects compared to multilayer graphene and the enhancement of the G band was larger than that of 2D band. Moreover, we confirm the appearance of D band in this study that is not clear in normal Raman spectrum. In our study, D band appearance is ascribed to the SERS effect resulted from defects induced graphene on Au NPs. Monolayer film of Au NPs under the graphene provided more highly enhanced graphene Raman signal compared to that on the graphene. The Au NPs-graphene SERS substrate can be possibly applied to biochemical sensing applications requiring highly sensitive and selective assays.