• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.652-658
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• 2013

A huge number of greenhouse soils in Korea have accumulated mineral elements which induce many nutritional and pathological problems. The present study was performed to the effects of the reduced fertilization on plant growth, and uptake and partitioning of minerals (N, P, K) and soluble carbohydrates using highly minerals-accumulated farmer's greenhouse soil. On the basis of the recommended application for tomato crop, the application rates of N, P and K were 110(50%)-5.2(5%)-41.5(35%)kg $ha^{-1}$, respectively, using Hoagland's nutrient solution. Tomato growth rates during the whole experiment were not significant between treatments, but it was found that a decrease in daily growth represented after 60 days of treatment (DAT). The reduced application led to a drastic decrease in the concentration of N, P and K in fruits, and, thus, this resulted in lower uptake after 40 DAT. The lower phloem export and utilization of soluble carbohydrates caused an accumulation of extra-carbohydrates in leaves, stems and fruits in the reduced application. The reduced fertilization induced the capture of N, P and K in leaves and of soluble carbohydrates in stems compared to the conventional application. In this study, we suggest that it is possible to delay the first fertigation time in minerals-accumulated soils without an adverse impact on crop growth, but it is necessary to regularly monitor mineral status in soil to ensure a balanced uptake, synthesis and partitioning of minerals and carbohydrates.

• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.604-612
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• 2017

In this study, the effects of planting density on the growth of chrysanthemum in a greenhouse were evaluated on two popular varieties (i.e., Sinma and Moonlight). Planting density treatments were as follows: 1) $12cm{\times}12cm$, 2) $6cm{\times}12cm$, 3) $6cm{\times}12cm$ with one-cell vacant, and 4) $6cm{\times}12cm$ with two-cell vacant. Size of each treatments indicate one chrysanthemum was planted in that sized cell that was rectangular shaped field and these treatments were located in a line. Moreover, "one and two-cell vacant" means that it makes middle point of the field empty, offers beside chrysanthemum larger spaces to grow. For the Sinma variety, the results of growth and flowering characteristics at the harvesting stage showed that leaf number, leaf length, flower length, and leaf area were highest when the crop was planted at the $12cm{\times}12cm$ density, and the next preferable density was $6cm{\times}12cm$ with one-cell vacant. For the Moonlight variety, the results showed that stalk height and diameter, leaf number and length, flower length, leaf area, and flower number were highest at the $12cm{\times}12cm$ planting density. For Sinma, ratios of marketable production were 87.5% and 83.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant, respectively. For Moonlight, ratios were 88.0% and 84.3% for the $12cm{\times}12cm$ and $6cm{\times}12cm$ with two-cell vacant.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.211-218
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• 1991

The allelopathic potentials of several Korean weeds were inverstigated in the greenhouse and laboratory. Aqueouse extracts and plant litters of several weeds were tested at different dilutions for allelopathic effect on germination and Barley growth of crop species. Among the several species of weeds. Portulaca oleracea and Chenopodium album had the highest allelopathic effect to the four species to 30%, while the extract of Portulaca oleracea increased those to 4.7% on an average when compare with control plant. In greenhouse experiment Portulaca oleracea highly reduced the emergence rate indices of barley, soybean. radish and corn to 30, 49, 36 and 68% that of control plant, respectively. Plant height and dry weight of indicate plants were reduced by the residues of Portulaca oleracea and Chenopodium album.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.406-413
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• 2011

Recently the fuel cell has been spotlighted as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell stacks fueled by methane for a ship were developed. Characteristics of power and efficiency depending on the number of cells in the stack, hydrogen conversion ratio, and active area of the cell are evaluated. Also the effects of air and methane supplying conditions on performance are analyzed. As a result, as the number of cells, hydrogen conversion ratio, active area of the cell, or supplied air flow rate increase, the stack power and efficiency increase. When the methane flow rate increases, the power increases. However the efficiency decreases. In addition, the case at the current of 976.4 A, voltage of 529.1 V, with corresponding power of 516.6 kW shows that the efficiency of fuel cell stack is 42.91%.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.711-711
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• 2009

Global warming has been widely recognized as a serious problem threatening the future of human beings. It is caused by the buildup in the atmosphere of greenhouse gases, such as carbon dioxide, methane, hydrofluorocarbons (HFCs), and sulfur hexafluoride (SF6). Particularly, SF6 has extremely high global warming potential compare to those of other global warming gases. One option for mitigating this greenhouse gas is the development of an effective process for capturing and separating these gases from anthropogenic sources. In general, gas hydrates can be formed under high pressure and low temperature. However, SF6 gas is known to form hydrate under relatively milder conditions. Therefore, technological and economical effects could be expected for the separation of SF6 gas from waste gas mixtures. In this study, we carried out morphological study for the SF6 hydrate crystals to understand its formation and growth mechanisms. The observations were made in high-pressure optical cell charged with liquid water and SF6 gas at constant pressure and temperature. Initially SF6 hydrate formed at the surface between gas and liquid regions, and then subsequent dendrite crystals grew at the wall above the gas/water interface. The visual observations of crystal nucleation, migration, growth and interference were reported. The detailed growth characteristics of SF6 hydrate crystals were discussed in this study.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.276-280
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• 2007

In order to select the coating materials to perilla seed for reducing endosulfan residue greenhouse soil, this study was conducted to develop seed coating method and materials and also to evaluate the effects of seed coating on germination and color contrast between soil and perilla seed for convenient sowing work. Talc and kaoline were selected as seed coating materials because easy coating and better color contrast than shell powder or lime. Water was more effective on germination compared to alcohol, com oil and spray sticker as adhesives for seed coating.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.1-10
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• 1996

Factory-style plant production systems of various kinds are the final goal of greenhouse production systems. These systems facilitate planning for constant productivity per unit area and labor under various outside weather conditions, although energy consumption is intensive. Physical environmental control in combination with biological control can replace the use of agricultural chemicals such as insecticides, herbicides and hormones to regulate plants. In this way, closed systems which do not use such agricultural chemicals are ideal for environmental conservation for the future. Nutrient components in plants can be regulafied by physical environmental control including nutrient solution control in hydroponics. Therefore, specific contents of nutrients for particular plants can be listed on the container and be used as the basis of customer choice in the future. Plant production systems can be classified into three types based on the type of lighting: natural lighting, supplemental lighting and completely artificial lighting (Plant Factory). The amount of energy consumption increases in this order, although the degree of weather effects is in the reverse order. In the addition to lighting, factory-style plant production systems consist of mechanized and automated systems for transplanting, environmental control, hydroponics, transporting within the facility, and harvesting. Space farming and development of pharmaceutical in bio-reactors are other applications of these types of plant production systems. Various kinds of state-of-art factory-style plant production systems are discussed in the present paper. These systems are, in general, rather sophisticated and mechaized, and energy consumption is intensive. Factory-style plant production is the final goal of greenhouse production systems and the possibilities for the future are infinte but not clear.

• Journal of Environmental Science International
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• v.23 no.6
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• pp.1003-1012
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• 2014

We examined the combined impacts of future increases of $CO_2$ and temperature on the growth of four marine diatoms (Skeletonema costatum, Chaetoceros debilis, Chaetoceros didymus, Thalassiosira nordenskioeldii). The four strains were incubated under four different conditions: present ($pCO_2$: 400ppm, temperature: $20^{\circ}C$), acidification ($pCO_2$: 1000ppm, temperature: $20^{\circ}C$), global warming ($pCO_2$: 400ppm, temperature: $25^{\circ}C$), and greenhouse ($pCO_2$: 1000ppm, temperature: $25^{\circ}C$) conditions. Under the condition of higher temperatures, growth of S. costatum was suppressed, while C. debilis showed enhanced growth. Both C. didymus and T. nodenskioldii showed similar growth rates under current and elevated temperature. None of the four species appeared affected in their cell growth by elevated $CO_2$ concentrations. Chetoceros spp. showed increase of pH per unit fluorescence under elevated $CO_2$ concentrations, but no difference in pH from that under current conditions was observed for either S. costatum or T. nodenskioeldii, implying that Chetoceros spp. can take up more $CO_2$ per cell than the other two diatoms. Our results of cell growth and pH change per unit fluorescence suggest that both C. debilis and C. didymus are better adapted to future oceanic conditions of rising water temperature and $CO_2$ than are S. costatum and T. nodenskioeldii.

• Journal of Korea Foresty Energy
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• v.18 no.1
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• pp.37-45
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• 1999

The greenhouse effect becomes the most serious environmental problem due to excessive emission of carbon dioxide. This effect is aggravated with the deforestation, particularly cleaning of tropical forest for agricultural use. As trees sequester carbon dioxide from atmosphere, forest and forest products play an important role in the use and reduction of carbon dioxide. Wood and wood products require far less energy than the alternatives such as steel, aluminium and concrete for production. Considering high probability of increasing costs in the use of fossil fuel, the relatively low energy requirement for wood processing to very important. Also wood and wood products perform as a long-term storage of carbon. Wood is therefore an environmentally desirable resource. Recently, many alternatives have been introduced for industrial use. In selecting resources, many aspects should be taken into consideration. Wood and wood products have less harmful effects on the environment than the alternatives. We should utilize wood and wood products more efficiently, which should be provided based on the sustainable forest management.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.577-596
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• 2018

ASEAN countries consist of vast coastal areas and thousands of islands that are vulnerable to the effects of climate change on sea level rise. It is believed that this will play an important role in reducing greenhouse gas emissions globally in order to minimize the damage suffered by ASEAN countries. To overcome this issue, biofuels have been used to minimize the impact on the environment by replacing fossil fuels and to reduce greenhouse gas emissions. In those cases of United States, Brazil and Europe, where biofuels are highly utilized, research, development and investment in this field have been actively conducted in the past. In ASEAN countries, however, it has not been a long time since the biofuel policies were established. To overcome this problem, we investigated the renewable fuel policy in the United States, Brazil and the European Union. Based on this, we suggested the utilization plan and prospect of biofuel policy in ASEAN countries.