• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.83-83
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• 2019

본 연구는 고품질 산양삼 생산을 위한 표준재배기술 개발을 위해 산양삼의 생육특성과 재배지의 입지환경 간의 상관관계를 구명하고자 하였다. 전국 9지역의 산양삼 재배지를 선정하여 13년생 산양삼의 생육특성을 조사하고, 각 재배지의 임상 및 토양 이화학성을 분석하여 입지환경과 산양삼 생육특성과의 상관관계를 확인하였다. 총 9개의 재배지 중에서 산양삼의 생육특성은 거창과 함양 재배지에서 다른 재배지에 비해 유의적으로 높은 것으로 나타났다. 임산과의 상관관계를 확인한 결과, 산양삼의 부피는 재배지 임상의 흉고직경과 유의적인 정의 상관관계를 보였고, 활엽수의 비율과 유의적인 부의 상관관계, 침엽수의 비율과는 유의적인 정의 상관관계를 보였다. 침엽수의 비율이 100%로 확인된 영월 재배지의 산양삼 생육특성이 다른 재배지에 비해 유의적으로 높지 않은 것으로 확인되어, 이러한 결과는 침활혼효림에서 침엽수의 비율과 상관관계가 있는 것으로 판단된다. 토양 특성과의 상관관계 분석에서는 재배지 토양의 pH, K, Ca, Mg과 생육특성 간의 유의적인 부의 상관관계를 확인할 수 있었다. 이와 같이 산양삼의 생육특성과 입지환경 간의 상관관계를 분석한 결과, 산양삼의 생육은 재배지 임상의 흉고직경이 크고, 침활혼효림에서 침엽수의 비율이 높으며, 토양의 pH, K, Ca, Mg 함량이 높지 않은 재배지에서 적합하다는 것을 확인할 수 있었다. 본 연구의 결과를 통해 산양삼 재배에 적합한 재배적지의 입지환경 조건을 확인할 수 있었고, 산양삼은 7~20년 동안 무농약, 무비료의 청정환경에서 생산하는 것이 원칙이기 때문에 본 연구의 결과를 활용하여 향후 산양삼의 예상재배지를 선정하는데 있어 도움을 줄 수 있을 것으로 사료된다.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.463-470
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• 2019

Wild-simulated ginseng is requires standard establishment on location environment for long-term and eco-friendly cultivation. The this study was carried out to investigate the correlation between growth characteristics and location environment of wild-simulated ginseng for selection of suitable cultivation area. Samples were collected from a 9 site of wild-simulated cultivation area and examined growth characteristics and location environment. Correlation coefficient between growth characteristics and location environment was analyzed using Spearman's rank correlation. The growth of wild-simulated ginseng was shown significantly higher in Geochang and Hamyang cultivation area. The results of correlation analysis was shown significantly correlation with percentage of conifer, total diameter at breast height, soil pH, K, Ca and Mg. The results of this study was clearly investigated the correlation between growth characteristics and location environment of wild-simulated ginseng, which is considered to will provide understanding for selection suitable cultivation area of wild-simulated ginseng.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.19-26
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• 2023

Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH₃ decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH₃ decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N₂ desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH₃ conversion and a high H₂ formation rate of 23.5 mmol/g_cat·min (30,000 mL/g_cat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N₂ desorption rates through the presence of medium basic sites.

• Clean Technology
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• v.27 no.3
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• pp.232-239
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• 2021

In order to develop a novel system named "thermal medium and gas circulation type pyrolysis system," this study was conducted to obtain basic data for process simulation before performing the pyrolysis experiment. Polypropylene (PP) was chosen as model material in the basic pyrolysis experiment instead of waste plastic and fluidized sand (hereinafter referred to as "sand"), and it was used as a heat transfer material in the "thermal medium and gas circulation type pyrolysis system." Ni was impregnated as an active catalyst on the sand to promote catalytic pyrolysis. The basic physical properties of PP were analyzed using a thermogravimetric analyzer, and pyrolysis was performed at 600 ℃ in an N₂ atmosphere to produce liquid oil. The distribution of the carbon number of the liquid oil generated through the catalytic pyrolysis reaction was analyzed using GC/MS. We investigated the effects of varying the pyrolysis space velocity and catalyst amount on the yield of liquid oil and the carbon number distribution of the liquid oil. Using Ni/sand, the yield of liquid oil was increased except with the pyrolysis condition of 10 wt% Ni/sand at a space velocity of 30,000 h^-1, and the composition of C₆ ~ C₁₂ hydrocarbons increased. With increases in the space velocity, higher yields of liquid oil were obtained, but the composition of C₆ ~ C₁₂ hydrocarbons was reduced. With 1 wt% Ni/sand, the oil yield obtained was greater than that obtained with 10 wt% Ni/sand. In summary, when 1 wt% Ni/sand was used at a space velocity of 10,000 h^-1, the oil yield was 60.99 wt% and the composition of C₆ ~ C₁₂ hydrocarbons was highest at 42.06 area%.

• Korea journal of population studies
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• v.29 no.1
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• pp.269-292
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• 2006

The current environmental problem is global, and threatens the very existence of human beings. Many factors have been argued as the causes of environmental problem. The examples include anthroponcentric human perspective on nature, increase in the knowledge on nature, development of technology, economic growth and unequal distribution, and population increase, etc. The scholars who argues population increase have focused on over-population. However, the estimation of optimum population size has not been attempted in terms of environmental carrying capacity. In such a context, this paper aims at estimating optimum population size in South Korea in terms of environmental carrying capacity. The estimation was done from two approaches. One was based on the state of environment, the other was based on 'the desirable state of environment' Koreans expect. The former is termed an objective approach, while the latter is termed an approach based on social consensus. About 47.5 millions were estimated from the former approach, and 48.5 millions from the latter approach. However, optimum population size increase by 50.5 millions if government increase environmental budget to 2.00% among total budget. As such, different optimum population size is estimated according to the values of variables. The most significant variable determining optimum population size is environmental budget, and followed by supply of clean energy. The estimated optimum population size was based on the time-series data from 1993 to 2002. Therefore, time-series data collected from other years will result in different estimation model, and then different optimum population size will be estimated.