• 한국제4기학회지
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• 제9권1호
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• pp.43-60
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• 1995

The Kanweoldo Deposit in the Cheonsoo Bay western coast of Korean Peninsula is considered to be influenced by severe freezing condition under cold humid environment of the last glacial age. The evidence of severe freezing in the some upper part of the fine-grained Kanweoldo Deposit is characteristically irregular wavy la-mellar structure with the interval of 2∼8mm. In particular lamina show very compacted fabrics composed of rounded or spheroidal discrete aggregates covered by silt caps. Such laminar structure and associated micro-fabrics might owe to soil freezing such as ice segregation in lens form cryophoresis pressure from growing ice and disturbance by frost-creep. Furthermore pedogenesis of cold-humid type such as gleyzation or peseudo-gleyzation also might af-fect the kanweoldo Deposit in the priod of severe cold-humid cli-mate of the Wrm. The Kanweoldo sediment and organic remnant(16,708 B.P. with error limit of 250 years) affected by severe cryogenic activities sug-gest that the paleoclimate of Late Wrm in Korea might be so cold and humid as to engender the cryogenic structure in subaerial silty and sandy silt deposits.

• 한국분무공학회지
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• 제8권2호
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• pp.1-6
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• 2003

The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.9-16
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• 2007

Since the liquid phase LPG injection(LPLI) system has an advantage of higher power and lower emission characteristics than the mixer type fuel supply system, many studies and applications have been conducted. However, the heat extraction, due to the evaporation of liquid fuel, causes not only a dropping of LPG fuel but also icing phenomenon that is a frost of moisture in the air around the nozzle tip. Because both lead to a difficulty in the control of accurate air fuel ratio, it can result in poor engine performance and a large amount of HC emissions. The experimental investigation was carried out on the bench test rig in this study. It was found that n-butane, that has a relatively high boiling point($-0.5^{\circ}C$), was a main species of droplet composition and also found that the droplet problem was improved by the use of a large inner to outer bore ratio nozzle whose surface roughness is smooth. The icing phenomena were decreased when the an engine head temperature was increased, although a large amount of icing deposit was still observed in the case of $87^{\circ}C$. Also, it was observed that the icing phenomenon is improved by using anti-icing bushing.

• 한국분무공학회지
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• 제8권1호
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• pp.9-15
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• 2003

The liquid phase LPG injection (LPLI) system is considered as one of the next generation fuel supply systems for LPG, vehicles, since it can accomplish the higher power, higher efficiency, and lower emission characteristics than the existing mixer type fuel supply system. However, during the injection of liquid LPG fuel into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. A problem is that the moisture in the air freezes around the outlet of a nozzle, which is called icing Phenomenon. It may cause damage to the outlet nozzle of an injector. The frozen ice deposit detached from the nozzle also may cause a considerable damage to the inlet valve or valve seat. In this work, the experimental investigation of the icing phenomenon was carried out. The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of the air temperature in the inlet duct. Also, it was observed that the icing occurs first in the inlet of a nozzle, and grows considerably at the upper part of the nozzle inlet and the opposite side of the nozzle entrance. An LPG fuel, mainly consisting of butane, has lower latent heat of vaporization than that of propane, which is an advantage in controlling the icing phenomenon.

• 천문학회보
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• 제41권2호
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• pp.50.3-51
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• 2016

Recent analysis on the thermophysical property of asteroids revealed that their thermal inertia decrease with their sizes at least for main belt asteroids. However, little is known about that of comet-like bodies. In this work we utilized a simple thermophysical model (TPM) to calculate the thermal inertia of a bare nucleus of the comet P/2006 HR30 (Siding Spring) and an asteroid in comet-like orbit 107P/(4015) Wilson-Harrington from AKARI observation data. From five spectroscopic observations of the targets, we find out that the former has thermal inertia of around $2,000J\;m^{-2}K^{-1}s^{-1/2}$ (using pV = 0.055) and the latter has about $1,000-2000J\;m^{-2}K^{-1}s^{-1/2}$ (using pV = 0.055 and 0.043, respectively). These are high enough for both of them to deposit water ice at few centimeters depth, and hence it is difficult to say they are cometary based on the results of this study. These values, however, dependent significantly on the errors of observation and the uncertainties of the input parameters, as well as other conditions which are ignored in simple TPM approach, such as shape model and surface roughness. Further detailed analyses on these cometary bodies will shed light on our understanding of the detailed surfacial characteristics of them.

• 한국해양학회지
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• 제10권1호
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• pp.1-6
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• 1975

A marine geological investigation of the glass sand deposit in the beach along the west coast of Ahnmyeon Island, South Chung Cheong Province, Korea was carried out to solve the problen of sand material migration, textural properties of the sands and the glass sand reserve for future exploitation. Several bos coring analyses by means of the internal sedimentary structure.i.e., cross- stratification show significantly that most sands are moving and accumulation along the mean vector direction of $N20^{\circ}E-N60^{\circ}$ E in the area investigated. The average mean size of the sand sediments in the area studied ranges from 0.212mm to 0.275mm. The mechanism of sand migration in the area is considered to be interplay between longshore drift and flood tidal current. The sorting value of the sands ranges from 0.24 to 0.50. Therefore, these sand sediments are characteristic to be "well sorted". The average chemical composition of the glass sand in the area is the following: $SiO\_2$:-90.8%, $Al_2O_3$: -2.18%, $Fe_2O_3$:-0.73%, CaO:-1.79. The binocular microscope examination of the sands show that most of the sands are characteristically ice- clear quartz in mineral composition and their count percentage is mostly 92% or 96%.

• 한국분무공학회지
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• 제12권1호
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• pp.38-44
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• 2007

Since the Liquid Phase LPG injection (LPLI) system has Advantages in power generation and emission characteristics compared to the mixer-type fuel-supply system, a variety of studies regarding LPLi system has been conducted and its applications are made in automobile industry. However, the heat extraction due to the evaporation of liquid fuel, causes not only a post-accumulation of fuel but also an icing phenomenon which is a frost of moisture in the air around the nozzle tip. Since there exists a difficulty in the accurate control of air fuel ratio in both fuel supply systems, it can result in poor engine performance and a large amount of harmful emissions. This research examines the characteristics of icing phenomenon and develops anti-icing bushing to prevent an icing on the surface of the injection tip. It was found that n-butane, which has a relatively high boiling point ($-0.5^{\circ}C$), was a main species of post-accumulation. Also the results show that the post-accumulation problem was allevaited the utilization of a large inner to outer bore ratio and smooth surface roughness. In addition, an icing phenomenon and its formation process were found to be mainly affected by the humidity and the temperature of inlet air in an inlet duct. Also, it was observed that an icing phenomenon is lessened using aluminum bushing whose end coincides with the end of fuel injection tip in length.

• 한국지열·수열에너지학회논문집
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• 제2권1호
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• pp.1-7
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• 2006

This paper was studied for optimum design of the used vaporizer at a satellite station. Generally, the cold air is created by temperature drop on the vaporizer surface. In addition, the frost creates ice deposit layer, therefore, heat transfer on vaporizer decreases into the adiabatic condition. By this reason, recent vaporizer system is installed as parallel type, and it takes three times of vaporizer capacity. But this vaporizer system requires much installation costs and restricted by some space. It is very important to solve this problem. This study paper is regarding $LN_2$ vaporizer where the utilization increases recently. There are three variable conditions which are used in this study research. First, fin lengths of 4000mm, 6000mm, 8000mm and 0, 4, 8 fin types were applied rut each vaporizer. Second, we applied four season condition which consist of humidity, temperature and air velocity to the experimental environment. Finally, pressure was applied to get flow rate during experiment. This paper objective is to propose vaporizer type and length data for best performance of vaporizer through experiment.

• 한국광물학회지
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• 제22권3호
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• pp.207-216
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• 2009

경북 울진 분천화강편마암에 배태된 코리아 자수정광상에 산출되는 자수정은 킹크밴드와 파동소광을 가지는 조립의 석영결정과 이들 사이에 변형의 흔적이 없는 세립의 석영으로 이루어진 쌍봉 입자분포를 보이며 세 유형의 유체포유물을 포획하고 있다. Type I 은 액상이 풍부한 포유물(액체+기포)로, 시스템이 완전히 어는 최초 온도($T_e$)는 $-52{\sim}-20^{\circ}C$, 얼음이 최초로 형성되는 온도($T_{m-ice}$)는 $-5{\sim}0^{\circ}C$(7~0 wt% NaCl), 균질화 온도($T_{h-total}$)는 $91{\sim}231^{\circ}C$로 측정되었다. Type II는 기체상(80~90 vol%)이 풍부한 포유물(액체+기포)로서, $T_e$는 $-56{\sim}-23^{\circ}C$, $T_{m-ice}$는 $-4{\sim}-2^{\circ}C$ (6~3 wt% NaCl), $T_{h-total}$은 $230{\sim}278^{\circ}C$로 측정되었다. Type III는 액체가 풍부하고 액체+기포+확인되지 않은 딸결정 ${\pm}$ 칼리암염(KCl)로 구성되어 있다. Type III의 $T_{h-total}$은 $210{\sim}271^{\circ}C$, 유체의 염도는 32~36 wt% NaCl로 측정되었다. 석영과 자수정이 보이는 조직적 특성과 유체포유물의 성분은 자수정이 모암과 함께 동력재결정작용을 받았음을 제시한다. 또한 포획된 유체포유물은 변성기원으로 변성작용은 적어도 $271{\sim}278^{\circ}C$ 이상의 환경에서 이루어졌음을 지시한다. 울진 코리아 자수정은 합성 자수정이나 산지가 다른 자수정의 감별증거로 볼 수 있는 독특한 유체포유물들이 포획되어 있다. 울진 코리아 자수정 내의 유체포유물은 화강암과 관련된 언양과 삼천포 자수정에 비해 NaCl 암염과 $CO_2$ 유체포유물이 산출되지 않고 있는 점이 주목할 만하다.

• 대한지리학회지
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• 제42권2호
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• pp.165-176
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• 2007

티벳고원의 서쪽, 중부 카라코람의 인더스 강이 지나는 Skardu 근처에서 발견된 약 1.3km의 두께를 보이는 Bunthang 시퀀스의 절대 연대측정을 우주 기원 동위원소인 $^{10}Be$과 $^{26}Al$의 비를 이용해서 측정했으며 약 2백 65만년전에 급격하게 퇴적된 것으로 확인되었다. 이러한 퇴적시기는 지금까지 발견된 가장 오래된 직접적인 빙하활동의 증거로서 이전의 고지자기 연구와도 일치한다. Bunthang 시퀀스는 아래에서부터 빙퇴석, 호성 퇴적물, 하천 퇴적물 그리고 다시 호성 퇴적물로 이루어지며 어떠한 단층운동의 증거도 발견되지 않는 점으로 미루어 볼 때 분지의 생성은 빙하의 하방침식에 의해서 만들어졌으며 빙하의 후퇴와 더불어 proglacial과 paraglacial 프로세스에 의해서 생성된 것으로 판단된다. 이 지역에 있어서 신생대의 활발한 지반 활동은 인더스 강의 구배를 변형시킴으로써 연구지역과 같은 국지적인 호소퇴적층의 활발한 퇴적을 용이하게 하였으며 또한 지반운동과 빙하의 침식에 의한 사면의 불안정성은 이러한 국지적 퇴적 작용을 더욱 촉발시켰을 것으로 판단된다. 이전의 연구와 본 연구의 결과로써 지난 제4기 동안 빙하의 활동이 약해진 것으로 보건데 지난 마지막 빙기 최성기를 정점으로 티벳고원에 커다란 빙상이 존재했다는 가설은 틀린 것으로 보인다. 이 지역에서 제4기 동안의 빙하 활동의 축소는 희말라야 산맥과 카라코람 산맥 중심의 급격한 융기로 인해 Indian monsoon의 유입이 줄어든 것에서 기인한 것으로 추측된다.