• 한국자동차공학회논문집
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• 제7권8호
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• pp.107-115
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• 1999

Hydrocarbon emission from spark ignition engines deeply relates with fuel evaporation mechanism. Therefore, fuel evaporation on the back of the intake valve is very important to understand fuel evaporation mechanism during engine warm up period. Intake valve heat transfer model was build up to estimate the amount of fuel evaporation on the intake valve back . Intake valve temperature was measured intake valve temperature is increased rapidly during few seconds right after engine start up and it takes an important role on fuel evaporation. The liquid fuel evaporation rate on the intake valve back proportionally increases as valve temperature increases, however its contribution slightly decreases as intake port wall temperature increases. The fuel evaporation rate on the valve back is about 40∼60% during engine warm-up period and it becomes about 20∼30% as intake port wall temperature increases. The estimation model also makes possible model also makes possible to review the effect of valve design parameters such as the valve mass and seat area on fuel evaporation rate through intake valve heat transfer.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.766-770
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• 2005

Cascade-Correlation Neural Networks Model(CCNNM) is used to estimate daily evaporation using limited climatical variables such as atmospheric temperature, dewpoint temperature, relative humidity, wind speed, sunshine duration and radiation. DeBruln equation is applied to estimate daily free-surface evaporation. It is converted into pan evaporation using pan coefficient. The results of CCNNM shows better than those of Debruin equation. This research represents that the strong nonlinear relationship such as evaporation modeling can be generalized by the CCNNM ; a special type of Backpropagation algorithm Neural Networks Model.

• 설비공학논문집
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• 제12권5호
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• pp.525-532
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• 2000

Evaporation heat transfer characteristics have been investigated experimentally when distilled water is sprayed on the outside wall of horizontal tubes in a evaporator. This problem is of particular interest in the design of evaporator of an absorption system. Hydrophilic surface treatment was employed to increase the wettability on copper tubes. The results indicate that evaporation heat transfer with hydrophilic tubes is shown to be 25-44% higher than that with bare tubes at evaporation pressure of 31.8 Torr(evaporation temperature$ 30^{\circ}C). Evaporation heat transfer rates of hydrophilic treatment tubes are improved substantially, comparing with those of conventional copper tubes in the wide range of operating parameters, such as water inlet temperatures, water mass flow rates and evaporation pressures.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2104-2113
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• 2004

Surface degreasing method with premixed flame is proposed as the removal method of adherent impurities on materials. Effects of adherent molecular thickness and surface potential energy on evaporation rate of adherent molecules and molecular evaporation mechanism were investigated and discussed in the present study. Evaporation processes of adherent molecules on surface molecules were simulated by the molecular dynamics method to understand thermal phenomena on evaporation processes of adherent molecules by using high temperature gas like burnt gas. The calculation system was composed of a high temperature gas region, an adherent molecular region and a surface molecular region. Both the thickness of adherent molecules and potential parameters affceted the evaporation rate of adherent molecules and evaporation mechanism in molecular scale.

• 설비공학논문집
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• 제5권1호
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• pp.18-26
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• 1993

The performance of the evaporation facility of low radioactive liquid waste is studied experimentally. The evaporation facility comprises storage pools, feeding pumps, evaporation units with 1,040 sheets of cloth and air handling units. As the results of this study, it is found that the evaporation rate increases as the waste feed rate increases, the relative humidity of induced air decreases, and the air velocity increases. The modified Dalton's evaporation equation derived from experimental data is $E_h=(0.0168+0.0141V){\Delta}H$. The optimum operating conditions of the evaporation facility are waste feed rate of $4.5./hr.m^2$ and air velocity of 1.47m/sec.

• 한국수자원학회논문집
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• 제42권2호
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• pp.117-129
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• 2009

전지구적 기온상승으로 인해 증발량이 증가할 것으로 예견되었으나, 다양한 지역에서 관측된 팬증발량은 지난 수십 년간 뚜렷한 감소추세를 나타내고 있다. 본 연구에서는 1960년부터 2007년까지 관측된 국내 18개 기상관측소의 팬증발량과, 증발에 관련된 강수량, 온도, 상대습도, 풍속, 일조시간, 일조율에 대한 변화를 분석하였다. 분석결과 팬증발량은 뚜렷한 감소현상을 나타내었으며, 강수량과 온도는 증가추세를, 상대습도, 풍속, 일조시간, 일조율은 감소추세를 나타내었다. 특히, 일조시간과 일조율의 감소추세는 팬증발량과 지역적으로 상당히 일치하고 있음을 확인하였다. 산점도를 그려 상관관계를 확인해본 결과, 일조시간과 일조율은 팬증발량과 양의 상관관계를 강하게 나타내고 있으며, 강수량의 경우는 팬증발량과는 음의 상관관계가 존재하였다. 강릉관측소 사례연구에서 Penman공식에 의해 추정된 개방된 수면에서의 증발량은 팬증발량에서 보인 것 같은 뚜렷한 하향추세가 검증되지 않아, 기존에 팬증발량 관측값으로부터 증발량을 추정하는 것은 장기적인 증발량 변화를 검토하기 위해서는 부적절함을 확인하였다. 마지막으로 팬증발량이 실제증발량과 서로 상호보완적 관계를 갖기 때문에, 팬증발량이 감소하더라도 실제증발량은 증가할 수 있음을 설명하였다.

• 대한토목학회논문집
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• 제30권3B호
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• pp.243-255
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• 2010

본 연구에서는 pan 증발량 분포와 추세를 분석하였다. 이를 위하여 전국 56개 기후관측지점에서 1973년부터 1990년까지 의 pan 증발량 자료를 수집하여 분석을 실시하였다. 분석을 위하여 계절적 영향을 고려하여 1월, 4월, 7월 그리고 10월의 월평균 일별과 연평균 일별 pan 증발량 추세를 분석하였다. 연구결과 연평균 일별 pan 증발량은 56개 연구지역 중에서 38개 연구지역에서 감소추세를 보이고 있고, 1월 평균 일별 pan 증발량의 경우 33개 연구지역에서 pan 증발량 감소추세를 보이고 있다. 4월의 경우 38개 지역에서 증가추세를 보이고, 7월의 경우 47개 지역에서 감소추세를 보여서, 전반적으로 감소추세를 보이고 있다. 10월의 경우 35개 지역에서 증가추세를 보여서 전반적으로 증가추세를 보이고 있다. 따라서 전반적으로 연별과 1월, 7월은 pan 증발량이 감소추세를 보이고, 4월과 10월은 증가추세를 보이고 있다. 또한 인근에 위치한 권역별로도 다른 추세를 보이는 것으로 나타나서 지리지형적 요인이 pan 증발량 추세에 영향을 미치는 것으로 판단된다. 11개 기후관측지점에서 1973년부터 2006년까지의 pan 증발량 자료와 기후요소자료를 수집하여 추세분석을 실시한 결과, 기온, 상대습도 그리고 풍속추세는 연별이나 월별 pan 증발량 추세와 서로 같거나 또는 상이한 경향을 보이나, 일사량 추세는 연 및 월별 모두에서 pan 증발량 추세와 동일한 경향을 보이고, 강수량 추세는 연 및 월별 모두에서 pan 증발량 추세와 상반된 경향을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제7권1호
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• pp.21-25
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• 2006

In this study, liquid crystal (LC) aligning properties for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method with electron beam system in accordance with the evaporation angles were investigated. Also, the control of pretilt angles homeotropic aligned LC on $SiO_x$ thin film as the function of the evaporation angles were studied. The uniform vertical LC alignment on the $SiO_x$ thin film surfaces with electron beam evaporation was achieved with all of the thin film angle conditions. It is considerated that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation. The values of the pretilt angles according to the evaporation angle were from about $0.7^{\circ}$ to about $3.4^{\circ}$. The highest pretilt angles of about $3.4^{\circ}$ in aligned NLC on the $SiO_x$ thin film surfaces by electron beam evaporation were measured under the condition of $45^{\circ}$. Also, good LC alignment states on the treated $SiO_x$ thin film layer by electron beam evaporation were observed at annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good thermal stability of LC alignment on the $SiO_x$ thin film by electron beam evaporation can be achieved.

• 열처리공학회지
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• 제14권3호
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• pp.151-154
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• 2001

$TiO_2$ thin film has wide application because of its high capacitanca, reflection, and good transmissivity in visible range. $TiO_2$ thin film can be made by thermal deposition method, reactive evaporation method, activated reactive evaporation(ARE) method. In the case of thermal deposition, the oxygen deficiency can occur because the melting point of Ti is very high. While in the case of reactive evaporation, high density $TiO_2$ can not be made, because reactive gas($O_2$) and evaporated material(Ti) are not fully combined, activated reactive evaporation, $TiO_2$ is easily deposited at lower gas pressure compared with reactive evaporation because the ionized reactive gas is made by plasma. Therefore, activated reactive evaporation is very useful to deposit the material having the high melting point. In this work, we formed $TiO_2$ thin film by activated reactive evaporation method. The surface of $TiO_2$ thin film was analyzed by X-ray photoelectron spectroscopy. The surface morphology which was analyzed by atomic force microscopy(AFM) shows that feature of the film surface is uniform. The dielectric capacitance, withstanding voltage were $600{\mu}F/cm^2$, 0.4V respectively. In further work, we can increase the withstanding voltage by improving the deposition parameter of substrates.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1689-1695
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• 2017

As a part of evaluating the volatility of iodide ions subjected to gamma irradiation, $I_2$ evaporation experiments were performed with $I_2$ and $I^-$ mixed solutions in the temperature range $26-80^{\circ}C$ in an open, well-ventilated space. The evaporation of $I_2$ was observed to follow primarily first order kinetics, depending on the $I_2$ concentration. The evaporation rate constant increased rapidly with increase in temperature. The presence of $I^-$ slightly reduced the evaporation rate of $I_2$ by forming relatively stable $I_3^-$. The effect of $Cl^-$ at <1.0 wt% on $I_2$ evaporation was insignificant. The evaporation rate constants of $I_2$ were $1.3{\times}10^{-3}min^{-1}\;cm^{-2}$, $2.4{\times}10^{-2}min^{-1}\;cm^{-2}$, and $8.6{\times}10^{-2}min^{-1}\;cm^{-2}$, at $26^{\circ}C$, $50^{\circ}C$, and $80^{\circ}C$, respectively.