• 한국태양에너지학회 논문집
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• 제36권5호
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• pp.31-50
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• 2016

To develope a greenhouse fog cooling system to control the temperature and relative humidity simultaneously to the target value, a theoretical analysis and experiments were done. The control process includes the measuring of environmental variables, setting and coding of the water and heat balance equations to maintain the target temperature and relative humidity in greenhouse, calculating of the open level of the greenhouse roof window that governs the natural ventilation and spray water quantity, and operating of the motor to open/close the roof window and pump to spray for water. The study results were shown to be very good because the average air temperature in the greenhouse was kept to be about $28.2^{\circ}C$ with the standard deviation of about $0.37^{\circ}C$ compared to the target temperature of $28^{\circ}C$ and the average relative humidity was about 75.2% compared to the target relative humidity was 75% during the experiments. The average outside relative humidity was about 41.0% and the average outside temperature was $27.2^{\circ}C$ with the standard deviation of about $0.54^{\circ}C$. The average solar intensity in the greenhouse was 712.9 W. The wind velocity of outside greenhouse was 0.558 m/s with the standard deviation of 0.46 m/s.

• 한국수산과학회지
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• 제46권6호
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• pp.970-972
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• 2013

We examined the relative growth of Microstomus achne during early life stages of laboratory-reared larvae and juveniles. Turning points in the relative growth of preanal length and upper jaw length against total length occurred during the settlement period (11.12-19.91 mm in total length). However, turning points in the relative growth of head length and eye diameter, as compared to total length, occurred during metamorphosis (17.57-22.47 mm in total length). Our results suggest that Microstomus achne concentrates its energy on the feeding apparatus (jaw) and digestive organs (intestine) rather than sensory or neural organs (eye, head) during early larval stage growth.

• Carbon letters
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• 제2권2호
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• pp.113-119
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• 2001

The advanced method for $CO_2$capture is currently one of the most important environmental issues in worldwide and it is therefore necessary to have available technologies, which minimize the discharge of $CO_2$ including Carbon-14 from nuclear facilities into the atmosphere. A key aspect of this work is to provide the technically principal data required to improve a $CO_2$ removal system for the utilization of regenerative sorbent use, specifically include suggestions regarding its modified column design (parallel dual-bed assembly), stop-restart operation and the economic feasibility of sorbent use. The removal performance of soda lime and the effects of relative humidity (RH) and packing bed-depth (BD) on $CO_2$ removal were investigated. In a single-bed, it revealed that the utilization of soda lime for $CO_2$ removal at line velocity of 13 cm/sec and bed depth of 12 cm increased with the increased relative humidity up to 85%. However, in the parallel dual-bed assembly applied with the stop-restart operation, a maximum utilization rate of soda lime for $CO_2$ removal was obtained even at 55% of RH and 8 cm of BD, specifically the utilization rate of soda lime by using this $CO_2$ removal assembly was about two-fold superior to that in a single-bed.

• 한국석유지질학회:학술대회논문집
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• 한국석유지질학회 2000년도 제7차 학술발표회 발표논문집
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• pp.14-30
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• 2000

Hierarchically controlled sequence stratigraphic analysis shows that the Lower Ordovician mixed carbonate-siliciclastic Mungok Formation, Korea consists of three depositional sequences: T1, T2, and T3. Sequence boundaries are generally marked by abrupt transition from coarse-grained shallow-water carbonates to fine-grained deeper-water carbonates mixed with fine-grained siliciclastics, and show indication of subaerial exposure such as karstification. Within this sequence stratigraphic framework, facies characteristics indicate that the Mungok sequences were mostly deposited in subtidal ramp environments. High-frequency cycles consist of upward-shallowing facies successions. Cycles of shallow-water and basinal deposits are not represented well, probably due to cycle amalgamation. Cycle stacking patterns do not show a consistent thickness change that reflects a large-scale sea-level change due to unfilled accommodation space. The Mungok sequences show that many factors including relative sea-level change and topography are involved in controlling sequence development on carbonate ramps. The depositional setting evolved from the high-energy ramps in the sequences T1 and T2 into the low-energy ramp in the sequence T3. Topography is interpreted to have been responsible for the different energy regimes of the carbonate ramps in the Mungok sequences. The high ramp gradient in the sequences T1 and T2 seems to be caused by space-time-dissociated differential sedimentation resulting in spatially narrow distribution of sediment filling, which in turn may be related to high rate of relative sea-level change. In contrast, low ramp gradient was maintained in the sequence T3 during slow changes of relative sea level resulting in broad distribution of sediment filling.

• Korean Chemical Engineering Research
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• 제54권2호
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• pp.181-186
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• 2016

최근에 저가의 고분자 전해질 연료전지(Proton Exchange Membrane Fuel Cells, PEMFC)용 비불소계 전해질 막 연구개발이 활발히 진행되고 있다. 본 연구에서는 sulfonated Poly(ether ether ketone)(sPEEK)막의 특성을 술폰화도, 상대습도, 단위 전지 온도에 따라 PEMFC 운전 조건에서 비교하였다. I-V 분극곡선, 수소투과도, 전기화학적 표면적, 막 저항 및 부하 전달 저항 등을 측정 분석했다. 술폰화도와 온도, 상대습도가 높을수록 성능이 높았으며, 특히 낮은 슬폰화도와 낮은 상대습도에서 이온 전도도 감소 때문에 성능이 큰 폭으로 감소함을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.134.1-134.1
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• 2011

As eco-friendly energy is in the spotlight, lots of countries are out to develop and disseminate renewable energy. However, Korea still remains in relative newcomer position for renewable energy. To overcome the present condition, it is necessary to carry out a study of establishment of renewable energy policy that is appropriate the present situation of Korea from examples of advanced countries. Among several renewable energies, wind energy is known to be the most reliable energy. Germany that has increased the share of wind energy in total energy supply is a representative leading country for wind energy. Therefore wind energy policy in Germany will be a role model for that in Korea. In this study, as a research of portfolio for wind energy policy of advanced countries, a wide survey for current status of wind energy and energy policy in Germany is carried out.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2564-2571
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• 2022

SiPMs are generally coupled into whole columns in gamma energy spectrum measurement, but the relationship between the distribution of whole SiPM columns and the energy resolution of the measured energy spectra is rarely reported. In this work, ∅ 3 × 3 inch NaI scintillator is placed on an 8 × 8 SiPM array, and the energy resolution of the ¹³⁷Cs peak at 662 keV corresponding to the γ-ray is selected as a reference. Each SiPM is switched to explore the influence of the number of SiPM arrays, distribution position, and reflective layer on the energy resolution of SiPMs. Results show that without coupling, the energy resolution is greatly improved when the number of SiPMs ranges from 4 to 32. However, after 32 slices (the area covered by SiPMs relative to the scintillator reaches 25.9%), the improvement in energy resolution and total pulse count is not obvious. In addition, the position of SiPMs relative to the scintillator does not exert much impact on the energy resolution. Results also indicate that by adding a reflective film (ESR), the energy resolution of the tested group increases by 10.38% on average. This work can provide a reference for the design and application of miniaturized SiPM gamma spectrometers.

• 한국세라믹학회지
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• 제39권10호
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• pp.907-911
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• 2002

Using the two-dimensional Wulff plot, the equilibrium shape of a sapphire crystal was investigated as a function of surface energy anisotropy. Depending on the relative values of surface energy for various facet planes, the projected shape of equilibrium sapphire was determined to be rectangle, parallelogram, hexagon or octagon. The results are compared with the experimentally observed shapes of internal cavities of submicron range in sapphire single crystals.

• 한국임산에너지학회:학술대회논문집
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• 한국산림바이오에너지학회 2011년도 정기총회 및 학술연구발표회
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• pp.88-89
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• 2011

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2010년도 춘계학술 발표회
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• pp.196-196
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• 2010