• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.66-70
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• 2010

The performance of 75 ton liquid rocket engine combustion chamber for a space launch vehicle was predicted through firing tests at low pressure. In low pressure tests of 75 ton LRE combustor chamber, the combustion characteristic velocity of 1750 m/sec and the specific impulse of 240 sec were obtained which are higher than the low pressure performance of 30ton combustion chamber. The combustion characteristic velocity of 1770 m/sec and the specific impulse of 278 sec at design point for 75 ton LRE combustion chamber were predicted by using the low/high pressure performance correlation of 30ton LRE combustion chamber.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1721-1728
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• 2010

본 연구의 목적은 USLE 모형의 적용 범위 확장에 따른 모형의 적정성을 평가하는 데에 있다. 본 연구는 300 $km^2$ 정도의 유역면적을 갖는 만경강 봉동 수위관측소 유역에서 유사유출량을 모의한 후 이를 실측치와 비교 분석하는 과정으로 수행되었다. USLE 모형의 주요 인자 등은 객체지향프로그램인 ArcView를 이용하여 산정하였으며, 이를 강우침식인자, 토양침식인자, 지형인자, 식생피복인자, 침식조절인자 등과 같은 주제도에 격자기반($30m{\times}30m$)으로 구현하였다. 본 연구의 대상유역에서 모의된 2009년 평균토양침식량은 206.7 $ton/km^2/year$이며, 토양침식량에 Vanoni(1975)와 Boyce(1975), USDA(1972)의 유사전달비(sediment delivery ratio)를 고려한 유사유출량은 각각 47.128 $ton/km^2/year$, 19.223 $ton/km^2/year$, 61.596 $ton/km^2/year$로 산정되었다. Vanoni(1975)의 유사전달비가 고려된 유사유출량은 47.128 $ton/km^2/year$로 봉동 수위관측소에서 실측된 2009년 유사유출량 42.330 $ton/km^2/year$와 비교적 유사하였다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.323-330
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• 2008

This study was carried out to evaluate the effect of application of cattle manure and chemical fertilizer on dry matter productivity and nutritive values of rye and hairy vetch according to two different sowing methods such as single or mixed-sowed cultivation. Dry matter and TDN yields for rye single culture, and rye and hairy vetch mixed culture were 7.2 and 4.0 ton/ha, and 8.0 and 4.4 ton/ha, respectively. They were significantly (p<0.05) higher than that (4.5 and 2.7 ton/ha) of hairy vetch single culture. Moreover, plots produced by mixed-sowing cultivation had a higher crude protein (CP) as 7.7% than that of only rye plot, and higher TDN and RFV as 55.8 and 79.4%, respectively. Within rye alone plots, completely cattle slurry application produced significantly higher annual DM and TDN yields (7.4 and 4.1 ton/ha) than those of P+K fertilization (7.2 and 3.9 ton/ha) as a chemical fertilizer and non-fertilizer (5.5 and 3.1 ton/ha). Cattle slurry application plot revealed 75.52 and 78.97% of N+P+K fertilization plot for annual DM and TDN, respectively. Within mixed-sowing cultivation with rye and hairy vetch, completely cattle slurry application produced 7.6 ton/ha DM and 4.5 ton/ha TDN, showing 79.50 and 86.77% of N+P+K fertilization plot, respectively. Furthermore, the CP content for cattle slurry plots was 8.5%, which was significantly (p<0.05) higher than those of other plots, and it was also highest in TDN (58.3%) and RFV (86). Overall, rye mixed-sowing with hairy vetch rather than rye alone sowing reduced DM yields, but leaded to enhancement of feed value and nutritive yields. And also, it would be expected that cattle slurry application in comparison with chemical fertilizers might result in reutilization of resources, improved forage quality and, extended harvest period by preventing feed value from rapidly deteriorating.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.142-149
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• 2014

This study has compared carbon storages, annual carbon uptakes and annual soil respiration by planting type in Dujeong park, Cheonan city. Four plantations were selected in Dujeong park: Pinus densiflora plantation, Quercus acutissima community, Quercus acutissima-Robinia pseudoacacia plantation, and Robinia pseudoacacia plantation. We investigated each plantations from February 2012 to March 2013. Carbon storage and annual carbon uptake in each plantations were calculated with allometric method (Lee, 2003), and soil respiration was measured by using LI-6400 (LI-COR). Carbon storages in Pinus densiflora plantation, Quercus acutissima community, Quercus acutissima-Robinia pseudoacacia plantation, and Robinia pseudoacacia plantation were $17.36tonCha^{-1}$, $88.63tonCha^{-1}$, $115.38tonCha^{-1}$ and 4$9.88tonCha^{-1}$, and annual carbon uptakes were $1.04tonCha^{-1}yr^{-1}$, $2.12tonCha^{-1}yr^{-1}$, $6.47tonCha^{-1}yr^{-1}$ and $3.67tonCha^{-1}yr^{-1}$, respectively. Average annual carbon uptakes per tree of Pinus densiflora plantation, Quercus acutissima community and Robinia pseudoacacia plantation were $1.81kgC{\cdot}treeyr^{-1}$, $17.86kgC{\cdot}treeyr^{-1}$ and $9.14kgC{\cdot}treeyr^{-1}$ and Quercus acutissima was the greatest. The amounts of carbon released from soil respiration in the same four plantations were $2.20{\mu}molCO_2m^{-2}s^{-1}$, $1.90{\mu}molCO_2m^{-2}s^{-1}$, $2.47{\mu}molCO_2m^{-2}s^{-1}$ and $2.51{\mu}molCO_2m^{-2}s^{-1}$, and annual soil respiration were estimated $6.66tonCha^{-1}yr^{-1}$, $5.33tonCha^{-1}yr^{-1}$, $7.20tonCha^{-1}yr^{-1}$ and $7.25tonCha^{-1}yr^{-1}$, respectively. In this study area, Quercus acutissima-Robinia pseudoacacia plantation has a significant contribution to the role of carbon sink. However, the contribution of Pinus densiflora plantation was evaluated less. The results of this study can be used as the necessary data for tree planting and management in urban park.

• Korean Journal of Organic Agriculture
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• v.21 no.2
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• pp.247-263
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• 2013

This study was conducted to investigate the effect of cattle manure application on productivity, feed value, and stock carrying capacity of forage crops in upland and paddy fields at Gang-Wondo area. In the result, dry matter yield of sorghum ${\times}$ sudangrass hybrids obtained was 15.12 ton/ha at the level of 150kg N/ha of composted cattle manure. Significantly highest values of crude protein and total digestible nutrients (TDN) yields obtained were 0.59 and 5.35 ton/ha at the level of 150kg N/ha of composted cattle manure in the first cutting, and 0.44 and 3.70 ton/ha at the level of 150kg N/ha of organic raw cattle manure in the second cutting, respectively. The values of $K_{CP}+K_{TDN}/2$ and $K_{ME}$ of sorghum ${\times}$ sudangrass hybrids obtained was 7.76 and 4.46 head/ha at the level of 150kg N/ha of composted cattle manure. The dry matter yield, crude protein and TDN yields of rice straw were 4.95, 0.16 and 2.75 ton/ha at the level of 100kg N/ha of organic raw cattle manure, and the values of $K_{CP}+K_{TDN}/2$ and $K_{ME}$ of rice straw were 1.89 and 3.43 head/ha. The dry matter yield of winter crops, rye+red clover was 4.36 ton/ha in upland field, and rye+hairy vetch was 4.19 ton/ha in paddy field at the level of 100kg N/ha of composted cattle manure. Crude protein and TDN yields of rye+red clover was 0.29 and 2.38 ton/ha at the level of 100kg N/ha of composted cattle manure in upland field, and rye+hairy vetch was 0.30 and 2.48 ton/ha at the level of 80kg N/ha of composted cattle manure in paddy field. The values of $K_{CP}+K_{TDN}/2$ and $K_{ME}$ of rye+red clover was 2.34 and 2.15 head/ha in upland field, and rye+hairy vetch were 2.27 and 2.11 head/ha in paddy field, respectively. As the result, the productivity, feed value, and stock carrying capacity of sorghum ${\times}$ sudangrass hybrids showed higher values with composted cattle manure than organic raw cattle manure. rye+red clover in upland field and rye+hairy vetch in paddy field were most adaptable mixed combinations for roughage production at Gang-wondo area, it may due to their highly productivity, feed value, and stock carrying capacity.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.3
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• pp.104-109
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• 1981

The experiment was designed to measure splash erosion and to investigate the relationships between soil detachment, kinetic energy and C factor at various soils and crops under the natural rainfall, using the modified Ellison cup. The results obtained were as follows: 1. Splash erosion increased as the texture was coarser, reaching a maximum amount in loamy sand of 12.6ton/10a/year, 9.7ton for loam, 9.0ton for sandy loam, and 7.0ton for clay loam. 2. Splash erosion positively related to kinetic energy ($EI_{30}$) but negatively to K value. 3. A considerable relationship between splash erosion and kinetic energy was observed under coverage less than 50%; however, it decreased with increasing canopy resulting in no relation over 90% coverage. The amount of soil detachment by natural rainfall ranged from 10 to 15ton/10a at various cropping systems. 4. The particle size distribution of splashed soil was similar to that of original one and fine sand($250-100{\mu}$) marked the highest detachment and splash.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.464-471
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• 2013

In this study, the resource efficiency and future metal resource requirement in photovoltaic (PV) production system were evaluated by using material balance data and life cycle assesment (LCA) method. As a result, in the resource efficiency of ferrous and non-ferrous metal, lead and tin had higher resource efficiency than other materials in all PV systems (SC-Si, MC-Si, CI(G)S, CdTe). In the resource efficiency of rare metals, gallium and rhenium in silicon system and rhenium and rhodium in thin-film system ranked as the first and second high resource efficiency. In case of rare earth metal, gadolinium and samarium took higher resource efficiency. The results of the future metal resource requirement in PV systems showed that 2,545,670 ton of aluminium, 92,069 ton of zinc, 22,044 ton of copper, 1,695 ton of tin and 31 ton of nickel will be needed by 2030 in South Korea, except resource recycling supplement.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.408-414
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• 2008

Importance of climate change and its impact on agriculture and environment has increased with the rise Green House Gases (GHGs) concentration in the atmosphere. To slow down the speed of climate change many efforts have been applied in industrial sectors to reduce GHGs emission and to enhance carbon storage. In agricultural sector, many researches have been performed on GHGs emission reduction, but few on the role of carbon sink. In this study, we investigated carbon balance and soil carbon storage in agricultural field in the barley-red pepper and barley-soybean cropping system. With the system for automatic measuring of carbon dioxide, net ecosystem production(NEP) was estimated to be $6.3ton\;CO_2\;ha-1$ for N-P-K chemical fertilizer treatment plot and $10.6ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer with swine manure treatment plot in the barley-soybean rotation cropping. In the barley-red pepper rotation cropping, it was $12.0ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer treatment plot and $13.2ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer with swine manure treatment plot. Soil carbon storage rate was estimated to be $0.7ton\;C\;ha^{-1}$ for the barley-soybean cropping system and $0.5ton\;C\;ha^{-1}$ for barley-pepper cropping system. In appeared that agricultural lands may contribute to the greenhouse effect as a potential carbon sink preserving carbon into soil.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.281-288
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• 2009

The objective of this study is to predict the expansion possibility of treatment capacity in public livestock manure treatment plant (PLMTP) integrated individual farmhouses. According to the treatment efficiency and cost reducing effect, expansion possibility was examined using three cases; (i) decrease of influent concentration from 20,000 mg/L BOD to 1,000 mg/L BOD, (ii) maintenance of low concentration influent with minimum revising existing facilities (BIOSUF) and (iii) maintenance of low concentration influent without revising existing facilities (liquid corrosion method, LCM). In BIOSUF, the treatment capacity increased from 130 ton/day to 300 ton/day. Also, LCM resulted in expansion of treatment capacity from 210 ton/day to 250 ton/day while that of designed concentration influent decreased from 210 ton/day to 190 ton/day. The treatment costs were 14,674 won/ton and 9,929 won/ton for BIOSUF and LCM, respectively. After some revisions, it will be changed to 7,221 won/ton and 8,277 won/ton. Therefore, it must be considered that the livestock manure treats to low concentration and flows into PLMTP for the efficient operation and reducing treatment cost.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.873-883
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• 2014

This study proposed an estimation method of allowable wave height for loading and unloading of the ship considering ship motion that is affected by ship sizes, mooring conditions, wave periods and directions. The method was examined validity by comparison with wave field data at pier $8^{th}$ in Pohang new harbor. The wave field data obtained with wave height of 0.10~0.75m and wave period of 7~13s in ship sizes of 800~35,000ton when a downtimes have occurred. On the other hand, the results of allowable wave height for loading and unloading of the ship in this method have obtained with wave heights of 0.19~0.50m and wave periods of 8~12s for ship sizes of 5,000, 10,000 and 30,000ton. Thus this method well reproduced the field data respond to various a ship sizes and wave periods. And the results of this method tended to decrease in 16~62% when have considered long wave, and it is decreased in 0~46% when didn't consider long wave than design standards in case of the ship sizes of 5,000~30,000ton, wave period of 12s and wave angle of $75^{\circ}C$. The allowable wave heights for loading and unloading of the ship proposed by design standards are didn't respond to various the ship sizes and wave periods, and we have found that the design standards has overestimated on smaller than 10,000ton.