• International Journal of Automotive Technology
• /
• 제2권3호
• /
• pp.109-115
• /
• 2001

A study has been conducted to clarify the effect of watery vapor concentration in hot ambient on droplet evaporation. Droplets of water, ethanol, n-hexadecaneand n-heptane were used in this experimental study. Ambient conditions are fixed at 470 K in temperature, 0.1 MPa in pressure and 2 m/s in velocity of ambient air. Watery vapor concentration was changed 0%～40% by 10% by add water to air. To obtain the time histories of droplet diameter after exposed in ambient, a suspended droplet in hot and humid ambient stream was synchronized with a back flash light, and enlarged droplet images were taken by a CCD camera. The evaporation rate constant of water droplet decreases slightly with the vapor concentration because diffusion velocity reduction of droplet vapor occurs on the surface. The values of ethanol and n-heptane droplet actively increase by effect that water from condensation of vapor flows into the droplet. The evaporation rate constant of n-hexadecane which has higher boiling point than water increases within around 30% of the concentration.

• 한국분무공학회지
• /
• 제4권1호
• /
• pp.27-33
• /
• 1999

An experimental study has been conducted to clarify the effect of vapor on droplet evaporation. Droplets of water, ethanol, n-hexadecane and n-heptane were exposed in air stream. Temperature, pressure, and flow velocity in the ambient air are 470K, 1 atm, and 2m/s, respectively. Measurements are carried out for the wide range of water vapor concentration$(0%\sim40%)$. To obtain the time histories of droplet diameter, suspended droplet in hot and humid air stream was synchronized with a back flash light, and enlarged droplet images were taken on a CCD camera. With the vapor concentration increasing, the evaporation rate constant of water droplet decrease slightly and the droplet of ethanol and n-heptane increase actively. The evaporation rate constant of n-hexadecane which has higher boiling point than water increases within around 30% of the concentration.

• 한국지구과학회지
• /
• 제35권3호
• /
• pp.168-179
• /
• 2014

이 연구의 목적은 관측주기가 짧은 천리안 위성의 수증기 영상자료를 활용하여 태풍의 전향위치와 시간까지 예측이 가능하도록 하는데 있다. 즉 수증기의 위성영상의 건조슬롯과 제트류의 남북진동의 관계를 이용하여 태풍진로의 전향위치를 보다 정확히 예측하는 것이다. 제트류는 제트스트리크의 위치와 지균풍 ${\upsilon}$성분의 크기에 따라 움직이는데, 지균풍 ${\upsilon}$ 성분이 남쪽방향으로 강화되면 제트류는 원형 제트로 발달하게 된다. 이때 수증기 영상에서는 건조슬롯이 남쪽으로 확대되고, 굴곡수분밴드(CMB) 거리가 좁혀지기 때문에 태풍이 전향하게 된다. 굴곡수분밴드가 위도 $15^{\circ}$ 이하이면 24시간 내에 태풍이 북 또는 북동으로 전향하게 된다. 결과적으로 태풍진로는 건조슬롯의 위치가 $32^{\circ}N$ 이하이면 $20-23^{\circ}N$이하에서 전향(2007년 1호 태풍 콩레이와 2012년 17호 태풍 즐라왓)하고, 건조슬롯이 $35^{\circ}N$ 이상 일 땐 $27^{\circ}$N에서 전향(2007년 4호 태풍 마니)하는 것으로 분석되었다.

• Macromolecular Research
• /
• 제11권6호
• /
• pp.495-500
• /
• 2003

UV-induced graft polymerization of glycidyl methacrylate (GMA) to a polypropylene (PP) membrane was carried out in the vapor phase with benzophenone (BP) as a photoinitiator. Attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) were utilized to characterize the copolymer. The degree of grafting increased with increasing reaction time, increased UV irradiation source intensity, and increased immersion concentration of the BP solution. The optimum synthetic condition for the PP-g-GMA membrane was obtained with a reaction time of 2 hrs, a UV irradiation source intensity of 450 W, and an immersion concentration of the BP solution of 0.5 mol/L. The pure water flux decreased upon increasing the degree of grafting and increasing the amount of diethylamino functional group introduced. The analysis of AFM and SEM images shows that the graft chains and diethylamino groups of PP-g-GMA grew on the PP membrane surface, resulting in a change in surface morphology.

• Journal of Mechanical Science and Technology
• /
• 제17권1호
• /
• pp.157-167
• /
• 2003

The exciplex fluorescence technique with the TMPD (tetamethyl-Ρ-phenylene-diamine) / naphthalene dopant system was applied in a combustion-type constant-volume spray chamber. A detailed set of calibration experiments has been performed in order to quantify the TMPD fluorescence signal. It has been demonstrated that the TMPD fluorescence intensity was directly proportional to concentration, was independent of the chamber pressure, and was not sensitive to quenching by either water vapor or carbon dioxide. Using a dual heated-jet experiment, the temperature dependence of TMPD fluorescence up to 1000 K was measured. The temperature field in the spray images was determined using a simple mixing model, and an iterative solution method was used to determine the concentration and temperature field including the additional effects of the laser sheet extinction. The integrated fuel vapor concentration compared favorably with the measured amount of injected fuel when all of the liquid fuel had evaporated.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
• /
• pp.619-622
• /
• 2006

Atmospheric correction is one of critical procedures to extract quantitative information related to biophysical variables from hyperspectral data. In this study, we attempted to generate the water vapor contents image from hyperspectral data itself and developed the atmospheric correction algorithm for EO-1 Hyperion data using pre-calculated atmospheric look-up-table (LUT) for fast processing. To apply the new atmospheric correction algorithm, Hyperion data acquired June 3, 2001 over Seoul area is used. Reflectance spectrums of various targets on atmospheric corrected Hyperion reflectance images showed the general spectral pattern although there must be further development to reduce the spectral noise.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.305-308
• /
• 2008

The goal of this study is to retrieve ASTER thermal radiometry using a radiative transfer model. The MODTRAN is used for the model because it is easy to use with high spatial resolution and it is possible to specify input parameters such as profiles of temperature, water vapor density, ozone, aerosols and any of the other gasses. Most of parameters such as temperature and water vapor profiles were obtained from the Terra MODIS. The selected ASTER scene images land and coastal area. The surface radiance of ASTER TIR bands were retrieved by MODTRAN and extracted atmospheric profiles from MOD07 and US standard 76 models. Radiance estimated using MOD07 data was systematically lower by about 0.5-1.0 $W/m^2$ sr ${\mu}m$ than that by US standard 76 model between the two cases.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1693-1696
• /
• 2004

Synchrotron X-ray micro-imaging technique was employed to monitor non-invasively the refilling process of water inside the xylem vessels in bamboo leaves. The consecutive phase-contrast X-ray images clearly show both plant anatomy and the transport of water inside the xylem vessels. Traces of water-rise, vapor bubbles and variations of contact angle between the water front and the xylem wall were measured in real time. During the refilling process, air bubbles are removed when the rising water front halts at a vessel end for a while. Subsequently, it starts rising again at a higher velocity than the normal refilling speed. Repeated cavitation seems to deteriorate the refilling ability in xylem vessels. In dark environment, the water refilling process in xylem vessels is facilitated more effectively than in bright illuminated conditions. Finally, X-ray micro-imaging was famed to be a powerful, high resolution, real time imaging tool to investigate the water refilling process in xylem vessels.

• 대한원격탐사학회지
• /
• 제35권6_3호
• /
• pp.1299-1312
• /
• 2019

육상 원격탐사에서 정량적 활용이 확대됨에 따라 대기보정의 중요성이 날로 증가하고 있다. 그러나 대기보정 처리의 난이도와 효과의 불확실성을 감안한다면, 대기보정은 필요한 활용 분야에 적용되어야 한다. 광학영상의 대기보정이 반드시 필요한 분야로 지표물의 생물리적 변수의 정량적 정보를 추출하는 경우와 시계열 자료 분석을 꼽을 수 있다. 지표물의 정확한 표면반사율을 도출하는 대기보정에서 가장 큰 영향을 미치는 요소는 시공간적으로 매우 가변적인 에어로졸 및 수증기량이다. 특히 고·중해상도의 다중분광영상 대기보정에서 시기와 공간해상도가 부합되는 에어로졸 및 수증기 자료를 얻는 데 어려움이 많다. 광학영상의 육상 대기보정에서는 대기자료의 획득 방법에 따른 적절한 기법의 적용이 필요하다. 육상 대기보정은 렘버시안 표면 가정으로 표면반사율이 산출되지만, 대부분의 지표면은 이방성 반사특성을 가지고 있기 때문에 BRDF보정이 추가적으로 적용되어야 하는 숙제를 가지고 있다. 육상지역의 광학영상 대기보정 방법은 지속적인 개선이 전망되며, 센서도 대기보정을 위한 추가적인 파장밴드 포함이 기대된다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2000년도 춘계 학술대회 논문집 통권 3호 Proceedings of the 2000 KSRS Spring Meeting
• /
• pp.49-54
• /
• 2000

Conventional methods for measuring winds provide wind velocity observations over limited area and time period. The use of satellite imagery for measuring wind velocity overcomes some of these limitations by providing wide area and near condinuous coverage. And its accurate depiction is essential for operational weather forecasting and for initialization of NWP models. GMS-5 provides full disk images at hourly intervals. At four times each day - 0500, 1100, 1700, 2300 hours UTC-a series of three images is received, separated by thirty minutes, centered at the four times. The current wind system generates winds from sets of 3 infrared(IR) images, separated by an hour, four times a day. It also produces visible(VIS) and water vapor(WV) image-based winds from half-hourly imagery four times a day. The derivation of wind from satellite imagery involves the identification of suitable cloud targets. tracking the targets on sequential images, associating a pressure height with the derived wind vector, and quality control. The aim of this research is to incorporate imagery from other available spectral channels and examine the error characteristics of winds derived from these images.