• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.90-96
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• 2003

Numerical analyses have been performed to obtain the absorption heat and mass transfer coefficients and the absorption mass flux from a falling film of LiBr solution. In the present study, the behavior of laminar-wavy falling film in the vertical absorber was studied analytically and experimentally. The change of absorption performance on mean film thickness, wave amplitude, wave celerity was analysed. The heat and mass transfer equations are solved simultaneously to give the temperature and concentration variations at the LiBr solution/refrigeration vapor interface and at the wall. Effects of uniform film, wavy film and film Reynolds number on the heat and mass transfer coefficients have been estimated. The analytical results of the uniform and wavy falling film in the bare tube was higher than experimental result for $Rd_{t}<100$. The absorption performance showed the maximum at the wavy film by the insert device(spring).

• 한국전기전자재료학회논문지
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• 제18권3호
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• pp.219-225
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• 2005

To investigate the effects of slurry temperature on the chemical mechanical polishing(CMP) performance of oxide film with silica and ceria slurries, we have studied slurry properties as a function of different slurry temperature. Also, the effects of each input parameter of slurry on the oxide CMP characteristics were investigated. The pH showed a slight tendency of decrease, the conductivity in slurries showed an increased tendency, the mean particle size in slurry decreased, and the zeta potential of slurry decreased with temperature. The removal rates significantly increased and maintained at the specific levels over 4$0^{\circ}C$. The better surface morphology of oxide films could be obtained at 40 $^{\circ}C$ of silica slurry and at 90 $^{\circ}C$ of ceria slurry. It is found that the CMP performance of oxide film could be significantly improved or controlled by change of slurry temperature.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.268-268
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• 2012

Adsorption and desorption of toluene from bare and $TiO_2$-coated silica with a mean pore size of 15 nm was studied using breakthrough curves and temperature programmed desorption. Thicknesses of $TiO_2$ films prepared by atomic layer deposition on silica were < 2 nm, and ~ 5 nm, respectively. For toluene adsorption, both dry and humid conditions were used. $TiO_2$-thin film significantly improved toluene adsorption capacity of silica under dry condition, whereas desorption of toluene from the surface as a consequence of displacement by water vapor was more pronounced for $TiO_2$-coated samples with respect to the result of bare ones. In the TPD experiments, silica with a thinner $TiO_2$ film (thickness < 2 nm) showed the highest reactivity for toluene oxidation to $CO_2$ in the absence and presence of water. We show that the toluene adsorption and oxidation reactivity of silica can be controlled by varying thickness of $TiO_2$ thin films.

• 센서학회지
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• 제14권6호
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• pp.395-401
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• 2005

A highly stable quartz crystal microbalance (QCM) that showed a stability of frequencies and exhibited a very low noise level has been developed. The long-term drift was <0.05 Hz/h over a period of 10 h, and the short-term rms (root mean square) noise was <0.015 Hz. Our QCM sensor was used as a humidity sensor employing a poly(methyl methacrylate) (PMMA) polymer film as a hygroscopic layer, which showed good characteristics in the relative humidity (RH) range of $2{\sim}90%$ RH. Comparing the characteristics of the QCM sensor with those of other types of humidity sensors employing PMMA film as a hygroscopic layer, and with other QCM sensors employing other hygroscopic layers is represented.

• Composites Research
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• 제26권1호
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• pp.60-65
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• 2013

A nanolaminate consisting of alternate layers of aluminium oxide ($Al_2O_3$) (5 nm) and zirconium oxide ($ZrO_2$) (20 nm) was deposited at an optimized oxygen partial pressure of $3{\times}10^{-2}$ mbar by pulsed laser deposition. The nanolaminate film was analysed using high temperature X-ray diffraction (HTXRD) to study phase transition and thermal expansion behaviour. The surface morphology was investigated using field emission scanning electron microscopy (FE-SEM). High temperature X-ray diffraction indicated the crystallization temperature of tetragonal zirconia in the $Al_2O_3/ZrO_2$ multilayer-film was 873 K. The mean linear thermal expansion coefficient of tetragonal $ZrO_2$ was $4.7{\times}10^{-6}\;K^{-1}$ along a axis, while it was $13.68{\times}10^{-6}\;K{-1}$ along c axis in the temperature range 873-1373 K. The alumina was in amorphous nature. The FESEM studies showed the formation of uniform crystallites of zirconia with dense surface.

• 한국토양비료학회지
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• 제27권2호
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• pp.125-135
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• 1994

본(本) 연구(硏究)는 참깨의 Plastic film(polyethylene)멀칭 재배(栽培)에 있어서 멀칭이 지온(地溫)과 근권(根圈)의 토양수분(土壤水分) 함량(含量)에 미치는 영향(影響)과 그것이 참깨의 입묘(立苗) 및 초기생육(初期生育)에 미치는 영향(影響)을 밝히고자 수행(遂行)되었다. 시험(試驗)은 사양토(砂壤土)인 시험포지(試驗圃地)에 품종(品種) 안산깨를 공시(供試)하여 실시(實施)하였는데 참깨재배에서 조우(遭遇)할 수 있는 충분(充分)한 환경변이하(環境變異下)에서의 멀칭효과(效果)를 밝히고자 파종기(播種期)를 4월(月) 25일(日), 5월(月) 10일(日), 5월(月) 25일(日) 및 6월(月) 10일(日)의 4수준(水準)으로 하고, 1991년(年)과 1992년(年)의 2개년(個年) 동일시험(同一試驗)을 반복실시(反復實施)하였다. 그 주요(主要)한 결과(結果)는 다음과 같다. 1. 참깨재배에 있어서 polyethylene film mulching은 파종기(播種期), 년차(年次), 생육기(生育期)에 따라 다르지만 근권(根圈)의 지온(地溫)을 일평균(日平均) $1.4{\sim}2.8^{\circ}C$ 상승(上昇)시키고, 근권토양수분(根圈土壤水分)은 일평균치(日平均値)로 건기(乾期)에는 0.5~3.0% 증가(增加)시키는 반면(反面), 강우량(降雨量)이 많은 시기(時期)에는 1.0~2.0% 정도(程度) 감소(減少)시켰다. 2. 참깨의 발아(發芽) 및 입묘세(立苗勢)는 지온(地溫)의 차이(差異)에 대단히 민감(敏感)하게 반응(反應)하였는데 파종후(播種後) 7일이내(日以內)에 정상적(正常的)으로 출현(出現)하려면 종자위치(種子位置)(토심(土深) 5cm)의 지온(地溫)이 일평균(日平均) $21.0^{\circ}C$이상(以上)이어야 했다. 3. 참깨의 발아(發芽) 및 입묘(立苗)는 종자위치(種子位置)의 토양수분함량(土壤水分含量)이 14.0~21.0%(V/V) (-0.4bar~-2.0bar) 범위(範圍)이면 제한요인(制限要因)이 아니었고, 이 범위내(範圍內)에서 토양수분(土壤水分)의 영향(影響)은 미미(微微)했으나 사양토(砂壤土)에서 14.0~15.0%(V/V) (-2.0~-2.5bar)일 경우 최고수분조건(最適水分條件)이었다. 4. 멀칭에 의한 일평균(日平均) 지온상승(地溫上昇)의 효과(效果)는 토양수분(士壤水分) 함량(含量)이 높을 경우 컸으며, 멀칭에 의한 입묘세(立苗勢)의 증대효과(增大效果)는 기온(氣溫)이 낮은 경우 현저(顯著)히 컸지만 파종기(播種期)가 일평균(日平均) 기온(氣溫)이 $19^{\circ}C$보다 저온(低溫)인 시기(時期)에는 입묘후생초기(立苗後生育初期)에는 묘지상부(苗地上部)가 저온(低溫)에 의해 생육(生育)이 억제(抑制)되었다.

• 생물환경조절학회지
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• 제17권1호
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• pp.32-37
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• 2008

참외 재배시설에서 시설 내부 필름 표면에 결로현상으로 부착된 수적량과 시설 외부 필름 표면에 부착된 분진 부착량이 적었던 PO-2에서 투광률이 71.2%로 가장 높았다. 겨울철 시설 터널에서 온도가 가장 낮은 새벽 시간의 기온은 노지보다 $11.8{\sim}14.5^{\circ}C$ 정도 높게 나타났으며, 피복자재에 따라서는 최고 $2.7^{\circ}C$차이가 났는데 PO-2에서 가장 높았다. 지온은 터널이 노지보다 $13.0{\sim}15.3^{\circ}C$ 정도 높았으며, PO-2에서 가장 높아 PE보다 $2.3^{\circ}C$ 높았다. 참외 과실 전체에서 엽산을 분석한 결과 엽산함량은 품종에 따라 $68.9{\sim}113.4{\mu}g/100g$ 정도로 나타났다. 저온기에 참외 과육에서 $45{\sim}53{\mu}g/100g$ 정도로 나타났으며, 보온성과 광환경이 우수한 PO-2에서 PE보다 17% 정도 높은 수준을 보였다. 그러나 외기 온도가 $15^{\circ}C$ 이상 확보된 시기에는 $55.2{\sim}75.2{\mu}g/100g$ 정도로 나타났으며, PO-2에서 PE보다 과육에서 36% 높은 수준을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.94.2-94.2
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• 2010

Indium tin oxide (ITO) Thin films were grown on Non-alkarai glass Substrates by PVD method and Subsequently Subjected to ($100^{\circ}C-350^{\circ}C$) Thermal Annealing (TA) In Nitr Oxygen ambinent. Most of all, The effect of TA treatment on the structural properties were studied by using X-Ray diffraction and atomic force microscopy, while optical properties were studied by UV-Transmittance measurements. After TA treatment, the XRD spectra have shown an effective relaxation of the residual compressive stress, As a result, XRD peaks increase of the intensity and narrowing of full width at half-maximun (FWHM). In addtion The microstructure, The surface morphology, the optical transmittance changed and improved, and we investigated The effects of temperature, Time and atmosphere during the TA on the structural and electrical properties of the ITO/glass on TA at $300^{\circ}C$. As a results, the films are highly transparent (80%～89%) in visible region. AFM analysis shows that the films are very smooth with root mean square surface roughness 0.58nm -2.75nm thickness film. It is observed that resistivity of the films drcreases T0 $1.05{\times}10^{-4}{\Omega}cmt$ $6.06{\times}10^{-4}{\Omega}cm$, while mobility increases from $152cm^2/vs$ to $275cm^2/vs$.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.166-174
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• 2008

Numerical study on the impingement process and the fuel film formation of the hollow-cone fuel spray was conducted under vaporization condition, and the effect of the wall cavity angle on spray-wall impingement structure was investigated. A detailed understanding of this phenomena will help in designing injection systems and controlling the strategies to improve engine performance and exhaust emissions of the Gasoline Direct Injection (GDI) engine. The improved Abramzon model was used to model the spray vaporization process and the Gosman model was adopted for modeling of spray-wall impingement process. The calculated results of the spray-wall impingement process were compared with experimental results. The velocity field of the ambient gas, the Sauter Mean Diameter (SMD) and the generated fuel film on the wall, which are difficult to obtain by the experimental method, were also calculated and discussed. It was found that the radial distance after the wall impingement and the SMD decreased with increasing the cavity angle and the temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.112-112
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• 2009

In this study, the effect of a long post-deposition thermal annealing(600 and 1000 $^{\circ}C$) on the surface acoustic wave (SAW) properties of polycrystalline (poly) aluminum-nitride (AlN) thin films grown on a 3C-SiC buffer layer was investigates. The poly-AlN thin films with a (0002) preferred orientation were deposited on the substrates by using a pulsed reactive magnetron sputtering system. Experimental results show that the texture degree of AlN thin film was reduced along the increase in annealing temperature, which caused the decrease in the electromechanical coupling coefficient ($k^2$). The SAW velocity also was decreased slightly by the increase in root mean square (RMS) roughness over annealing temperature. However, the residual stress in films almost was not affect by thermal annealing process due to small lattice mismatch different and similar coefficient temperature expansion (CTE) between AlN and 3C-SiC. After the AlN film annealed at 1000 $^{\circ}C$, the insertion loss of an $IDT/AlN/3C-SiC/SiO_2/Si$ structure (-16.44 dB) was reduced by 8.79 dB in comparison with that of the as-deposited film (-25.23 dB). The improvement in the insertion loss of the film was fined according to the decrease in the grain size. The characteristics of AlN thin films were also evaluated using Fourier transform-infrared spectroscopy (FT-IR) spectra and X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) images.