• 한국생산제조학회지
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• 제25권6호
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• pp.498-503
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• 2016

Many types of robot systems are used in the mass production line of thin film solar cells and flat panel displays. There are some issues such as the deflection and the vibration of the end-effector because robots handle large and heavy substrates at high speed. Heavy payload and high speed cause much vibration because the end-effector (fork) is made of carbon fiber reinforced polymer because of its light weightiness and sufficient stiffness. This study performs a dynamic simulation of an 8.5G solar cell substrate handling robot, including rigid and flexible bodies and a vibration controller. The fifth polynomial trajectory and the zero vibration derivative input shaping algorithm are applied. The vibration reduction is also proved in the experiments.

• 공업화학
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• 제21권5호
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• pp.500-504
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• 2010

다중벽 탄소 나노튜브(Carbon nanotube, MWNTs)의 우수한 전기적 기계적 특성과 폴리우레탄의 우수한 기계적 물성을 이용하여 우수한 전기 전도성 복합체를 제조하기 위하여 말단기가 polyurethane로 기능화 된 탄소 나노튜브(PU-g-MWNTs)를 제조하였다. 말단기에 형성된 폴리우레탄과 고분자 메트릭스 간의 상용성으로 인한 계면 접합력으로 인해 기능화된 CNT 복합체 기능화 되지 않은 CNT에 비해 우수한 분산성을 나타내었다. PU-g-MWNT/PU 복합체의 전기 전도성을 PU-g-MWNT의 농도에 따라 측정하였으며 percolation threshold 이론에 의해 해석하였다. 그 결과 PU-g-MWNT/PU 복합체의 전기전도성은 임계농도 0.78 wt%과 임계지수 0.945를 가짐을 확인하였다.

• 멤브레인
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• 제18권3호
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• pp.256-259
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• 2008

본 연구에서는 poly(acrylonitrile-butadiene-styrene) (ABS)에 carbon graphite와 zeolite 4A를 첨가하여 복합 필름을 제조하고 공기와 수증기 투과 특성을 살펴보았다. 복합 필름의 경우 모든 경우에서 순수한 ABS에 비해서 산소와 질소의 투과도가 감소하였으며, 산소의 투과도 감소가 질소의 투과도 감소보다 약간 큰 관계로 산소/질소 선택도도 조금 감소하였다. 또한, 수증기 투과도도 순수한 ABS에 비해서 약 1/2로 감소하였다. 이러한 투과도의 감소는 ABS에 filler를 첨가함으로 인하여 물질 확산 경로의 tortuosity가 증가했기 때문인 것으로 생각된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.54.1-54.1
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• 2011

The conventional energy-production system by burning fossil fuels releases many pollutants and carbon dioxide($CO_2$) to the environment. Therefore, many countries pay attention to new and renewable energy and invest in the development of these new technologies for the future energy security. One of the most promising of these technologies is a photovoltaic system. In this study, Life Cycle Assessment(LCA) is carried out to analyse the environmental issues(e.g. global warming, abiotic resource depletion) of CdTe photovoltaic system. The spatial and temporal scope of this study was set in Korea during 2004~2005. We assumed that CdTe photovoltaic system was installed in Mokpo where the amount of solar irradiation was higher than other places in Korea. Based on the present data and some assumptions, greenhouse gas emission was 39.2g $CO_2$-eq./kWh. Therefore the electricity produced by CdTe photovoltaic system is more environmentally friendly than the conventional power generation system.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.91-91
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• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• 열처리공학회지
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• 제12권3호
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• pp.231-239
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• 1999

Volume fraction and morphology of retained austenite, tensile properties of TRIP type high strength steel sheet with Fe-C-Si-Mn-Cu chemical composition have been investigated. The retained austenite of granular, bar and film type existing in specimen was obtained after intercritical annealing and austempering. The granular type retained austenite increased with increase of intercritical annealing and austempering temperature. With increase of intercritical annealing temperature, retained austenite and carbon contents increased. Maximum contents of retained austenite was obtained by austempering at $400^{\circ}C$. The maximum tensile strength was obtained by austempering at $450^{\circ}C$ and maximum elongation was obtained at $400^{\circ}C$. T.S${\times}$E.L value increased with increase of retained austenite contents due to the elongation strongly controlled by contents of retained austenite, but tensile strength was affected with various factors such as bainitic structure etc.

• 열처리공학회지
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• 제13권2호
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• pp.91-97
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• 2000

The structure and mechanical properties of TiN and TiCN thin films deposited on STD61 steel substrates by the RF-sputtering methods has been studied by using XPS, XRD, micro-hardness tester, scratch tester, and wear-resistance tester. XPS results showed that the TiCN thin film formed with chemical bonding state. The TiN thin films grew with (111) orientation having the lowest strain energy by compressive stress, whereas the TiCN thin films grew with both (111) and (200) orientation, but (200) orientation having the lowest surface energy becomes dominant as carbon contents increase. The pre-etching treatment of substrate did not affect on the preferred orientation of thin films, but it played an important role in improving mechanical properties of thin films such as the hardness, adhesion and wear- resistance. Especially, the TiCN thin films showed the superior wear resistances due to high hardness and low friction coefficient compared with TiN thin films.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.185-189
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• 2005

We reported here nano-scale electrical phase-change recording in amorphous $Ge_2Sb_2Te_5$ media using an atomic force microscope (AFM) having conducting probes. In recording process, a pulse voltage is applied to the conductive probe that touches the media surface to change locally the electrical resistivity of a film. However, in contact operation, tip/media wear and contamination could major obstacles, which degraded SNR, reproducibility, and lifetime. In order to overcome tip/media wear and contamination in contact mode operation, we adopted the W incorporated diamond-like carbon (W-DLC) films as a protective layer. Optimized mutilayer media were prepared by a hybrid deposition system of PECVD and RF magnetron sputtering. When suitable electrical pulses were applied to media through the conducting probe, it was observed that data bits as small as 25 nm in diameter have been written and read with good reproducibility, which corresponds to a data density of $1 Tbit/inch^2$. We concluded that stable electrical phase-change recording was possible mainly due to W-DLC layer, which played a role not only capping layer but also resistive layer.

• 한국재료학회지
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• 제18권6호
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• pp.302-306
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• 2008

Polycrystalline germanium (Ge) thin films were grown by metal organic chemical vapor deposition (MOCVD) using tetra-allyl germanium [$Ge(allyl)_4$], and germane ($GeH_4$) as precursors. Ge thin films were grown on a $TiN(50nm)/SiO_2/Si$ substrate by varying the growth conditions of the reactive gas ($H_2$), temperature ($300-700^{\circ}C$) and pressure (1-760Torr). $H_2$ gas helps to remove carbon from Ge film for a $Ge(allyl)_4$ precursor but not for a $GeH_4$ precursor. $Ge(allyl)_4$ exhibits island growth (VW mode) characteristics under conditions of 760Torr at $400-700^{\circ}C$, whereas $GeH_4$ shows a layer growth pattern (FM mode) under conditions of 5Torr at $400-700^{\circ}C$. The activation energies of the two precursors under optimized deposition conditions were 13.4 KJ/mol and 31.0 KJ/mol, respectively.

• 한국물환경학회지
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• 제22권1호
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• pp.45-50
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• 2006

This study was performed to evaluate the air lift reactors (ALR) by variations of HRT and recycling rate. Air lift reactor was composed of bioreactor and clarifier above it. To remove organic matters and nitrogen through the formation of microbic film and filtration, bio-filter reactors were filled with clay, glass, bead, waste plastic, respectively. Influent wastewater was fed to biofilter reactor, and effluent wastewater from bio-filter reactor was injected ALR again, instead of adding external carbon source. Effluent BOD concentration was satisfied with lower than 10 mg/L in recycling rate 100% regardless of the variation of HRT and the kinds of media materials. In HRT 4 hr, recycling rate 100%, BOD removal efficiency rate was from about 85 to 90%, COD removal efficiency rate was higher than 90%. Effluent TN concentration was satisfied with less than 20 mg/L, if HRT was maintained by over than 6 hr regardless of recycling rate and media materials. Over than HRT was 4 hr, microbes concentration in air lift reactor was maintained over than 2,500 mg/L constantly, not sensitive to environmental condition, and organic removal was effective as it was higher.