• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.42-42
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• 2021

산채류 종자는 주로 농가의 자가 채종으로 생산되고 있다. 농가에서는 종자만을 생산하기 위해서 산채를 재배하지 않으며, 대체로 산채를 수확한 후 채종하는 실정이다. 하지만 종자생산을 위해서 생채나 나물을 언제까지 수확해야 하는지에 대한 한계기 설정이 불분명하다. 따라서 전북농업기술원 허브산채시험장에서는 개미취와 섬쑥부쟁이는 5년생, 곤달비는 3년생 묘목을 이용하여 종자생산을 위한 적정 생채수확 한계기를 설정하고자 시험을 실시하였다. 55% 차광막을 설치한 노지 재배포장에서 생채 수확 한계기를 각각 2020년 4월, 5월, 6월까지로 두어 한계기별 생채 수량, 상품 수량 및 상품율과 개화 시기, 개화율 및 결실률 등을 조사하였다. 개미취의 생채 상품율은 수확 한계기가 늦어질수록 다소 떨어지는 경향이었으며, 개화 시기는 무처리와 4월까지 수확은 동일하였으나, 5월, 6월까지는 수확 한계기가 늦어질수록 지연되었다. 개화율은 대부분 10% 미만이었으며, 5월과 6월까지 생채를 수확한 경우는 추대 및 개화가 거의 되지 않았다. 섬쑥부쟁이는 생채를 6월까지 수확하면 4월까지 수확한 경우보다 약 2배 이상의 생채를 얻을 수 있으나 상품율은 확연히 떨어졌다. 개화 시작은 무처리와 4월까지 수확이 타 처리에 비해 빨랐으나 개화종은 시기에 상관없이 비슷하였다. 또 4월까지 생채를 수확한 경우 무처리보다 개화율, 결실률이 더 높았다. 5월 이후 수확은 생육 부진으로 이어져 개화 및 결실률이 매우 떨어졌다. 곤달비는 개미취와 섬쑥부쟁이에 비해 생채 수확 한계기가 늦어질수록 상품 수량이 눈에 띄게 증가하였으며, 처리 간 추대 시기도 차이는 없었다. 개화율은 5월 수확 이후 낮아졌으며, 결실률은 6월 이후에 급격히 떨어졌다. 따라서 채종을 위해서는 차광재배 시 개미취와 섬쑥부쟁이는 생채 수확시기를 4월 하순, 곤달비는 5월 하순까지로 한정해야 할 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.302-304
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• 2007

전세계적으로 에너지난과 환경오염난을 겪고 있는 가운데 최근 대체에너지에 대한 관심이 어느 때보다 높은 시기이다. 다양한 대체에너지 중에서도 태양광 에너지는 우리나라 환경에 적합해 많은 연구가 진행 중인 분야이다. 대부분의 태양광 발전 시장이 결정질 실리콘 태양전지가 차지하고 있으나 경제성의 한계로 인해 최근 염료감응형 태양전지가 이를 대체할 수 있는 전지로 주목받고 있다. 본 연구에서는 염료감응형 태양전지의 상대전극에 증착하는 백금층의 두께 변화가 가져오는 출력특성의 영향을 연구했다. 상대전극에 증착되는 백금 박막은 염료감응형 태양전지의 매커니즘에서 입사광의 반사와 전기화학적 촉매작용 역할을 하는 것으로 박막의 두께가 두꺼워지면 반사율이 증가해 염료 분자가 받는 에너지가 늘어날 것으로 예상했다. 상대전극에 백금 Sputtering하는 시간을 1분에서 최대 5분까지 차를 두어 상대전극의 백금 박막의 두께를 $50nm{\sim}250nm$로 변화를 주어 측정한 결과, 250nm의 백금 박막층을 갖는 염료감응형 태양전지보다 백금 박막층이 150nm의 두께를 가질 때 가장 좋은 효율을 출력한다는 것을 알 수 있었다. 이를 통해 상대전극의 백금 박막층에 의한 거울 효과와 촉매작용의 한계와 전자의 흐름 장애에 대한 결과를 얻을 수 있었다.

• Journal of Korean Society of Transportation
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• v.30 no.6
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• pp.59-70
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• 2012

The relative importance of leisure trip has been increased after adopting the five-day workweek system and considering the higher income level. Thus, the value of travel time for intercity leisure trips should be estimated to conduct a reasonable benefit/cost analysis for railway construction projects. In this paper, the value of travel time was estimated separately for each trip purpose such as business, leisure, and other non-business than leisure. The estimated values of leisure travel time ranged from 5,310 to 14,185 (won/hr) by altering travel mode, and were increased by 42-107% when comparing with those of non-business travel time. Besides, how to apply the value of intercity leisure travel time for B/C analysis of railway projects was suggested. For the construction case of a railway connecting Chuncheon and Sokcho, the estimated benefit was increased by 2.3%.

• Journal of Energy Engineering
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• v.13 no.4
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• pp.267-274
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• 2004

Theoretical analysis for predicting the heat transport limitations of screen mesh wick and sintered wick heat pipes was performed. The heat pipe diameter was 8mm and water was used for working fluid. For the 250 mesh, each capillary pressures and heat transport limitations, thermal resistances were analyzed according to the operating temperatures, wick thicknesses and inclination angles, based on the effective capillary radius (r$\_$c/), porosity ($\varepsilon$) and permeability (K). The wick capillary limitation was increased as the operating temperature and the wick thickness were increased, and generally the sintered wick showed higher heat transport limitations than that of the screen wick. The thermal resistance of the screen wick was higher than that of the sintered wick and both thermal resistances were linearly increased as the wick thickness was increased.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.97-103
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• 2005

In this paper, effects on the heat transport limitation of heat pipe by the wick structural factors were theoretically analyzed for the sintered-copper wick heat pipe. Uniformity of particle size and sintering process were acted as dominant factors on the pore distribution and wick porosity, and small deviations of the wick thickness and the pore size greatly affected the heat transport limitations of the heat pipe. Especially, slight variations of the wick thickness, mean particle radius and capillary radius along the vapor temperatures and inclination angles remarkably changed the capillary limitation of the heat pipe.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.133-142
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• 2008

The term, travel time reliability, refers to variations in journey time that travelers cannot predict. This issue has been one of the main research topics in transport studies. This paper, especially, investigates the value of travel time reliability. The marginal substitution rate method is suggested as the way for the valuation and travelers' stated preference data are collected based on a choice experiment. A mode choice model is estimated using the data surveyed. The parameters of travel costs and travel time reliability from the model are used to calculate the marginal substitution rate that is interpreted as the value of travel time reliability. The value is arranged by travel areas of intercity and urban trips and by journey purposes of working and non-working types. The result of this research is expected to be helpful of conducting more cautious economic feasibility studies of transport schemes.

• Resources Recycling
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• v.33 no.3
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• pp.12-20
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• 2024

The global cement industry emits approximately 2.9 billion tons of greenhouse gases, of which 1.74-1.89 billion tons are emitted from limestone, which is the main raw material for clinkers. Therefore, the feasibility of using slag, a non-carbonated CaO-based raw material, must be investigated, and the physical properties of cement must be considered. In this study, the mixing ratios of the raw mix and properties of cement were analyzed. The CaCO₃ replacement ratio was limited when one type of slag was used; however, when the mixed slag was utilized, the CaCO₃ replacement ratio increased by more than 12 %. The compressive strength of the slag-incorporated cement was lower than that of Ordinary Portland Cement (OPC). Therefore, the lime saturation factor (LSF) of the raw mix and fineness of the cement were increased to improve the compressive strength. The compressive strength of cement with improved fineness was similar to that of OPC for a CaCO₃ replacement ratio of up to 6 %, and it decreased as the CaCO₃ replacement ratio was increased to 9 %. When both fineness and LSF were increased, the compressive strength and flow value of the cement with a CaCO₃ replacement ratio of 12 % were similar to that of OPC.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.606-613
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• 2005

The badge-type diffusive sampler for the measurement of formaldehyde in indoor air using three types of colorimetric methods such as chromotrophic acid(CTA), 3-methyl-2-benzothiazolinone hydrazone(MBTH), and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole(AHMT) method. The washing of the collection filter with several cleaning solution was effected with satisfactory results, regardless of the types of cleaning solutions. The concentrations of absorbance solution in each colorimetric method were experimentally determined by considering the sampling rates. The variation blank values in each colorimetric method was below 15%. As compared with CTA and AHMT methods, the reproducibility of MBTH method was excellent and was below 10% relative standard deviation. The collected formaldehyde mass and time-weighted concentration had a good correlation (correlation coefficient > 0.93). The limit of detection and limit of quantitation, and minimum sampling time were closely correlated to the sampling rates for the measurement of formaldehyde in each method.

• Environmental and Resource Economics Review
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• v.4 no.2
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• pp.267-289
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• 1995

석탄에 대한 아황산가스 규제가 발전산업에 미치는 제반 효과들을 측정하기 위해서는 생산요소의 왜곡된 분배로 인한 생산비용의 증가 또한 고려하여 암묵요소가격을 이용한 일반비용함수를 추정해야 한다. 아황산가스 규제를 포함한 여러 형태의 규제하에서 생산요소간의 한계기술대체율이 시장가격율과 일치하지 않음으로써 기업들의 생산비용최소화는 이루어지지 않기 때문이다. 1975년부터 1990년까지의 표본기간동안 아황산가스 규제로 인하여 미국 석탄발전소들의 생산비용이 평균적으로 6.1% 증가되었고 아황산가스를 추가적으로 1톤 저감하는데 드는 한계비용을 배출량몫 가중평균치로 측정하면 규제를 받은 기업들은 평균적으로 매년 539달러를 소비하였다. 생산요소인 자본과 노동 그리고 저유황석탄의 수요량은 평균적으로 5.8%, 5.2%, 그리고 29.6% 각각 증가된 반면 고유황석탄 수요량은 0.7% 감소되었으며 규제를 받은 기업들의 연 생산성은 평균적으로 1.52% 감소되었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1339-1346
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• 2015

In a previous study, baekseolgi with xylitol or sucralose was comparable to baekseolgi with sugar in terms of all sensory characteristics. However, the hardness of sucralose baekseolgi increased considerably during storage while that of xylitol baekseolgi remained unchanged. To improve the physical limitations observed in sucralose baekseolgi, a combination of sucralose and xylitol were substituted for sugar when preparing baekseolgi (SL0~SL100, SLn; baekseolgi where sugar was replaced with n% sucralose and 100-n% xylitol based on relative sweetness to sugar). All SLn baekseolgi samples were not significantly different from sugar baekseolgi in terms of sensory properties. The moisture content was not different between sugar and xylitol baekseolgi (SL0), but decreased significantly as the amount of sucralose increased (P<0.01), which correlated with cohesiveness of baekseolgi. Texture profile analysis revealed that hardness of SLn baekseolgi increased without any noticeable change in moisture content after storage at $4^{\circ}C$ for 7 days. In addition, the hardness after storage was the highest in sucralose baekseolgi (SL100), which was comparatively lower in SL0~SL80 containing xylitol presumably due to the hygroscopic characteristics of xylitol. In particular, SL20 was found to be comparable to sugar baekseolgi in terms of moisture and cohesiveness during storage. The results showed that the combination of xylitol and sucralose could be a potential sugar substitute in terms of not only sensory characteristics but also physicochemical properties.