• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.447-452
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• 2011

Depletion of petroleum increased the need of alternative energy and chemical resources. Biomass, a renewable resource, can be transformed to bioenergy and biomaterials, and the materials from biomass will ultimately substitute petroleum based energy and chemical compounds. In this perspective, production of C4-C6 compounds for bioenergy and biomaterials are described for understating of current research progress. n-Butanol and n-butyric acid, the major C4 compounds, are produced by Clostridium tyrobutyricum, Clostridium beijerinckii, and Clostridium acetobutylicum. n-Hexanoic acid, a typical C6 compound, is produced by Clostridium kluyveri and Megasphaera elsdenii. Reported maximum amount of n-butanol, n-butyric acid and n-hexanoic acid was 21, 55, and 19 g/L, respectively, and extraction of these C4-C6 compounds are induced increase production by those anaerobic bacteria. In addition, a new bacterium Clostridium sp. BS-1 produced 5 g/L of n-hexanoic acid using galactitol.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.385-399
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• 2021

Among human-induced seismicity, fluid production has been one of the causes. In this report, the mechanism that causes an earthquake due to a decrease in the fluid pressure inside the reservoir during fluid extraction is summarized. As case studies, the Lacq gas field in France, the Cerro Prieto geothermal field in Mexico, and the Groningen gas field in the Netherlands, which have become issue recently, were introduced. It is showed that fluid production, ground subsidence, and the presence of existing faults were closely related with the induced seismicity. Therefore, for the development of oil or gas field and geothermal field, it is important to investigate the presence of faults that may cause earthquakes in the reservoir, to monitor ground subsidence during production in real time, and to control production.

• Journal of Korea Foresty Energy
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• v.18 no.2
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• pp.92-99
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• 1999

This study was carried out to understand the primary production of biomass, vertical biomass distribution in the stand and the difference of biomass production for part of the trees by stand density for natural Pinus densiflora forest at Mt. Baekdoo located in northeastern China. The primary production of biomass was estimated by the layers of trees, shrubs, herbs for five density classes. For the biomass estimation of the Pinus densiflora trees in stern, stembark and the above-ground tree, the regression model of logW = a + blog(D$^2$H) + c(D$^2$H) was adapted for all of the density classes where W is dry weight, D$_1$ diameter at breast height, and H, tree height. For the biomass estimation in branch and needle, and the needle area, the regression model of logW=a+blogD+cD was adapted for all of the density classes. With increasing stand density the biomass of trees increased but that of shrubs and herbs decreased. Net primary production of biomass in parts of the tree also increased with increasing stand density. However the percentage of the needle biomass among the total biomass in the above-ground tree decreased with increasing stand density. Consequently, primary production rate of biomass in the above-ground tree increased. The primary production of biomass for each part of the trees in natural Pinus densiflora natural forests showed in descending order : stern, needle, branch, and stembark regardless of stand density.

• Journal of Korea Foresty Energy
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• v.7 no.1
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• pp.11-21
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• 1987

To estimate the biomass, net production and nutrient distribution of Pinus Koraiensis and Quercus mongolica stand, experimental plots located in Kwangju of Kyonggi-do were selected. Ten sample trees selected account of DBH distribution were felled and the diagram of oven-dry weight distrubution of leaves, branches and stems for each 1m segment was constructed. The logarithmic regression equations between dry weight of each component and the variable of $(DBH)^2$ H obtained. The standing crops were estimated to be as much as 152.07 and 156.02 tons of dry matter per hectare in P. koraiensis and Q. mongolica stand respectively. The net production was estimated as 24.66 and 20.35t/ha$\cdot$yr and the net assimilation rate was 1.90 and 3.42kg/kg$\cdot$yr in same order. Particulary large proportions of nitrogen. calcium and magnesium were found in soil of P. koraiensis stand, phosphours and potassium in overstory of it. At Q. mongolica stand, large proportions of nitrogen. phosphorus. potassium and magnesium were found in soil and calcium in overstory. The amounts of litter fall was 4.013t/ha$\cdot$8 months in P. koraiensis stand and 3.490t/ha$\cdot$8 months in Q. mongolica stand.

• Journal of Korea Foresty Energy
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• v.7 no.1
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• pp.1-10
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• 1987

This study was carried out to estimate the aboveground biomass of Cryptomeria japonica and Chamaecyparis obtusa which was planted in Changsong district, the southern part of the Korean peninsula. Nine sample trees at each plot(20m x 20m drom C. japonica of 20-year-old and C. obtusa of 25-year-old, according to DBH distribution. were felled to measure the dry weights of stem, branches and leaves sectioned respectively. Since it is very difficult to separate leaves from twigs. all green parts including pure leaves and twigs were tentatively treated as 'leaves'. 1. The logarithmic regression equations between dry weight of each component (stem. branches. leaves land the variable of $(DBH)^2{\cdot}H$ were obtained (Table 6). The aboveground standing crops was estimated 108. 75ton/ha in C. japonica and 112.56 ton/ha in C. obtusa. Percentage of each part based on the aboveground standing crop in stand was and in order of stem >leaves>branches for C. japonica and in order of stem> branches> leaves for C. obtusa repectively. 2. Net production of each stand was estimated as 1:3.32ton/ha/yr in C. japonica and 11.69ton/ha/yr in C. obtusa. and its composition was in order of stem>leaves>branches for both species. 3The net assimilation rate was estimated as 1.10 and 1.2lkg/kg/yr, the efficiency of leaves to produce stem was 0.71 and 0.75 kg/kg/ha and biomass accumulation ratio was 8.16 and 9.63kg/kg/yr in each stand of C. japonica and C. obtusa respectively.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.90-103
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• 2018

This paper presents the development of two ANN models which can predict an optimum production rate by controlling choke size in oil well, and gas injection rate in gas-lift well. The input data was solution gas-oil ratio, water cut, reservoir pressure, and choke size or gas injection rate. The output data was wellhead pressure and production rate. Firstly, a range of each parameters was decided by conducting sensitive analysis of input data for onshore oil well. In addition, 1,715 sets training data for choke size decision model and 1,225 sets for gas injection rate decision model were generated by nodal analysis. From the results of comparing between the nodal analysis and the ANN on the same reservoir system showed that the correlation factors were very high(>0.99). Mean absolute error of wellhead pressure and oil production rate was 0.55%, 1.05% with the choke size model, respectively. And the gas injection rate model showed the errors of 1.23%, 2.67%. It was found that the developed models had been highly accurate.

• Korea Petroleum Association Journal
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• no.4 s.194
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• pp.44-48
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• 1997

올해 들어 석유 공급이 증가함에 따라 지난해 원유가격을 상승시킨 수급구조의 건조세는 상당히 완화될 전망이다. 1996년의 세계 석유제품 수요는 예상보다 빠르게 그리고 OPEC이외의 생산국들의 공급보다 훨씬 빠르게 증가했다. 이것은 OPEC 석유에 대한 수요증가와 원유가격의 상승을 가져왔다. 지난해 말 ,세계 원유의 수출가격은 지난해 초보다 25%이상이나 상승했다. 그러나 1997년에 시장상황은 바뀔 것이다. 세계의 경제성장은 에너지와 석유에 대한 수요를 증가시키는 반면, 非OPEC의 석유공급은 더욱 증가할 것이다. 북해와 라틴아메리카의 생산증가는 非OPEC의 생산을 190만 b/d이상 증가시킬 것이다.1996년 생산이익으로부터 거둬들인 재정수입은 탐사와 생산에 추가투자를 가증하게 해 줄 것이다. 非OPEC의 공급증가는 OPEC석유에 대한 수요를 줄일 것이다. UN의 승인하에 1996년말에 재개된 이라크의 석유수출은 OPEC회원국들에게 가격하락을 막고 시장의 균형을 위하여 생산량을 감축하도록 요구할 것이다. 가격은 아마 북반구의 성수기의 높은 가격수준에서 수요저하로 인해 하락할 것이다. 한편 구소련의 석유생산과 소비는 안정적이었다. 국제 에너지기구(IEA)는 구소련의 수요는 올해 감소를 멈추고 1996년의 450만 b/d 수준에 머무를 것으로 보고 있다. IEA는 또한 구소련의 석유생산이 20만 b/d증가하여 한해 평균 720만 b/d로 예상하고 있다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.525-528
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• 2009

Power generation of wind turbine which is installed in wind farm should be measured to predict economic feasibility of wind farm. Also electric power company want to verify wind turbine performance which is stated by manufacturer. The International Electrotechnical Commission(IEC) published 61400-12-1 "Power performance measurements of electricity producing wind turbines" for test of wind turbine power performance. In this paper, measurable sector of wind speed is analysed based on IEC 61400-12-1 to verify power curve of wind turbine with various wind turbine in wind farm.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.63.1-63.1
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• 2011

본 연구에서는 제주 삼달 지역의 Hub 높이에서 측정된 실측 자료와 기상청에서 측정된 AWS 자료 1년(2010년)치를 토대로 Wind-Pro에 적용하여 풍황자원 분석을 하였다. 허브의 실측높이인 삼달지역 관측자료(100m)와 허브 보정값인 기상청 AWS 자료(15m)를 통해 각각의 연간발전량과 단지 효율을 측정하여 비교 분석하였고 실측높이와 보정치를 이용한 값을 적용하여 발전량 및 효율을 산출 비교하고 이를 통해 그 차이점을 분석하고자 한다. 이는 단지분석 시에 발생될 보정값의 불확도를 판단하는데 그 의의가 있다.

• New & Renewable Energy
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• v.5 no.2
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• pp.31-38
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• 2009

The performance test of a wind turbine in a wind farm is generally carried out by the owner to verify the power curve of the wind turbine given by the turbine manufacturer. The international electro-technical commission provides the IEC 61400-12-1 standard on "Power performance measurements of electricity producing wind turbines". By using this code, one can easily find the suitable met-mast (meteorological mast) location for the wind data whether a wind farm is potential or already built. In this paper, the valid sectors for wind turbines installed in the HanKyoung wind farm, south-west in Jeju island are analyzed on the basis of the code by considering the wind farm layout. Among these sectors, the optimal met-mast location is presented for the power curve verification of the wind farm.