• Tribology and Lubricants
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• 제5권1호
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• pp.51-56
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• 1989

The Lubricational characteristics of O/W Emulsions of beef tallow and mineral oil based lubricants are studied in a roller on disk apparatus. It is revealed that the coefficients of friction with both emulsion lubricants exhibit essentially similar behavior; that is, they rapidly decrease to 0.1% concentration and after they constants with increasing oil concentration, and that, with oil in water emulsions of a concentrations as low as 5wt% practically forms a elastohydrodynamic film. One hand, surface temperature effect on lubricants has virtually no severe, and that, the minimum EHL film chickness estimated that it begins to increase at a concentration of several percent; the effect of particle diameter becomes maked there after.

• 한국안전학회지
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• 제25권6호
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• pp.81-85
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• 2010

In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. The vegetable insulation oils are highly biodegradable, have negligible effect on the environment, human health and ecosystem. Therefore, to assure their safe use in electrical power systems, it may require some processing and modification to improve some of their physical, chemical, thermal and electrical properties. This paper provides a comparative results of the electrical breakdown properties of several vegetable insulation oils and mineral oil to use as dielectric fluid in environmental-friendly pole transformer. Also, the electrical breakdown property of the Nomex and kraft insulation papers in vegetable insulation oil is examined.

• 설비공학논문집
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• 제27권8호
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• pp.402-408
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• 2015

A series of numerical simulations have been carried out to study the performances of cyclone-type oil separators, which are designed for refrigeration-system compressors. The corresponding working fluid is R22, which is a typical refrigerant, whereby a mineral-oil droplet is supplied (Ed-highlight-My interpretation). The outlet-tube length in relation to the total chamber volume is considered a design parameter. Depending on the tube length, the separation efficiency varies from 98.7% to 99.3%, while the predicted pressure drop is between 5.1 kPa and 6.4 kPa. Considering both the pressure drop and separation efficiency, the length of the outlet-port tube of the separator is 152 mm.

• 유기물자원화
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• 제15권1호
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• pp.149-158
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• 2007

토양중 유박의 온도(10, 20, $30^{\circ}C$) 및 수분변화 (양토 : 포장용 수량의 40, 50, 60, 70%, 사양토 : 포장용수량의 50, 60, 70, 80%)에 따른 무기화정도를 검토하기 위해 토양과 피마자유박, 대두박, 탈지강을 혼합하여 실내항온배양을 30일간 실시하여 무기태 질소를 측정하였다. 또한 PVC파이프로 컬럼을 제작하여 실외 포장에 토양컬럼을 설치하여 30일 후 토양깊이에 따른 무기화를 조사하였으며 실내 및 실외배양에 사용된 토양은 사양토와 양토로 이들 두 토양간의 무기태질소의 생성량을 조사하였다. 피마자박, 대두박 및 탈지강을 토양에 혼합하여 실내항온배양을 실시한 결과 배양온도가 높고 수분함량이 높을수록 무기태 질소의 생성량이 증가되었으며 양토보다 사양토에서 무기태 질소의 생성량이 높았다. 한편 토양컬럼 실험결과 토심에 따른 무기태 질소의 생성량은 토심이 깊어짐에 따라 감소하였으며 실내항온배양과 마찬가지로 사양토가 양토보다 무기태 질소의 생성량이 높았다.

• 아태비즈니스연구
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• 제8권2호
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• pp.57-73
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• 2017

In this paper RCA and TSI has been analyzed based on Korean and Chinese lists of export (HS 6 units) and list of companies and products with competitive advantage has been deduced. The results of RCA and TSI analysis are as follows. From the list of 20 most exported items from Korea to China the RCA index for eleven of them (based on common items from 2011-2015) is bigger than 1, thus showing comparative advantage. As for the TSI index, all of the items has shown (+) value, and has been analyzed as specialization in export. In other words, companies in the fields of mineral fuel; mineral oil; organic chemicals; electrical equipment and parts; as well as optical, precision and medical instrument are industries with competitive advantage. From the list of 20 most exported items from China to Korea the RCA index for twelve of them (based on common items form 2011-2015) is bigger than 1, thus also showing comparative advantage, and the TSI index has also shown (+) value for all of the specified items, meaning specialization in export. Industries of mineral fuel; mineral oil; iron and steel, articles of iron and steel; machinery and mechanical parts, electrical equipment and parts; as well as optical, precision and medical instruments have shown competitive advantage.

• Corrosion Science and Technology
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• 제7권6호
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• pp.350-361
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• 2008

Canada's oil sands contain one of the largest reserves of oil in the world. According to recent estimates, there are nearly 180 billion barrels of oil in the Canadian oil sands trapped in a complex mixture of sand, water and clay. More than 40 companies have been currently operating or developing oil sands facilities since the first production in 1967. The process of oil sands upgrading is similar with down stream refinery, but the corrosion environment in upgrading refinery is often more severe than in the refinery because of high chlorides, mineral contents, carbonic acid, heavy viscosity and fouling, higher naphthenic acid [$NA-R(CH_{2})nCOOH$], and greater sulfur contents. Naphthenic acid corrosion (NAC) which is one of the most critical corrosion issues in up & downstream refinery plants was observed for the first time in 1920's in refinery distillation processes of Rumania, Azerbaizan (Baku), Venezuela, and California. As a first API report, the 11th annual meeting stated sources and mechanism of NAC in early 1930's. API has been developing the risk base standards, such as API RP580, 571, and Publication 581 which are based on the worst NAC damage in the world since 2000. Nevertheless not only the NAC phenomena and control in Canadian sands oil process are not much widely known but also there are still no engineering guidances for the Canadian sands oil in API standards. This paper will give NAC phenomina and materials selection guidance against NA environment in Canadian oil sands upgrading processes.

• 한국작물학회지
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• 제43권3호
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• pp.141-146
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• 1998

Production of medicinal soybean [Glycine max (L.) Merrill], characterized with black seed, white stripe at hilum border, yellow cotyledon and small seed, is increasing with increasing consumption. The objective of this study was to investigate the chemical composition of medicinal soybean seed and to provide basic information, for the characterization of these soybeans among genetic resources. Forty-four lines of medicinal soybeans collected from Korea and two control cultivars, 'Hwangkeumkong' (Yellow seed coat) and 'Geomjeongkong l' (Black seed coat) were planted at the Research Farm of the College of Natural Resources, Korea University, located at Namyangju City on May 25, 1996. Seeds of these lines were harvested at full maturity and analyzed for protein, oil, sugar, starch and mineral contents. Mean protein and oil content of the medicinal line seeds were 42.6 and 16.1%, respectively, and those of the control cultivars were in the middle range for protein and oil content. However, sugar and starch content of the medicinal line seeds appeared to be in the lower range of the distributions compared to the control cultivars and were 10.0 and 1.68%, respectively. Mean P, K, Ca, and Mg contents of the seeds of medicinal soybean lines were 15.9, 21.5, 3.11, and 2.81 mg/g, respectively, indicating that these lines had higher P, K, and Mg and lower Ca contents when compared to the control cultivars. Mean Na and Fe contents were 671 and 224 mg/kg, respectively, showing lower Na and similar Fe contents. The observed results provided that chemical compositions of medicinal soybean were, on average, different from those of the general soybean cultivars.

• Tuberculosis and Respiratory Diseases
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• 제41권6호
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• pp.670-675
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• 1994

본 저자들은 스쿠알렌(Shark liver oil)을 반복적으로 사용한 75세 남자 환자에서 방사선 소견과 객담 검사로 진단한 지방성 폐렴 1예를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• 지구물리와물리탐사
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• 제14권3호
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• pp.203-213
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• 2011

시간경과(time-lapse) 탄성파 저류층 모니터링은 생산 저류층에서 유체 흐름의 변화를 영상화 하기 위해, 동일한 탐사 지역에서 시간 차를 두고 탄성파 탐사를 여러 번 수행하여 자료를 획득, 처리, 분석하는 과정으로 요약할 수 있다. 생산 중인 광구에서는 가스 및 오일을 생산하면서 저류층 내 유체의 변화를 모니터링하여, 가채 자원량 및 생산에 필요한 변수 값의 변화를 확인하는 필수도구로 사용된다. 또한 특정 생산정의 최적 회수율 평가, 회수율을 증대시키기 위한 생산기법, 그리고 이를 위한 변수 선정에도 적용될 수 있다. 최근에는 이산화탄소($CO_2$) 지중저장에도 모니터링 기법을 적용하여 저장된 이산화탄소의 변화 양상을 분석하는 사례가 보고되고 있다. 국내 업체들이 최근 외국 사이트에서의 석유광구 지분 참여 등 투자를 늘리고 있는 상황에서 정확한 투자 가능성 진단과 기술 자체의 고부가가치를 생각할 때, 시간경과 탄성파 저류층 모니터링은 향후 그 중요성이 더욱 증대될 연구 분야이다. 이 논문에서는 시간경과 탄성파 저류층 모니터링에 대한 이해를 돕기 위해 시간경과 탄성파 탐사의 개념, 설계, 방법, 자료처리 해석 등에 대하여 간략히 소개한다.

• 한국자원공학회지
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• 제55권6호
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• pp.624-634
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• 2018

인도네시아는 신규 유전 발견이 줄어들고 원유 순수입국으로 전환됨에 따라 석유 생산을 늘리고자 공동개발계약(Kerja Sama Operasi, KSO)을 통해 소규모 광구 개발을 위한 국내 투자 유치 활성화에 노력하고 있다. 하지만 KSO는 계약자 고위험 저수익의 계약형태이며, 계약자가 석유개발에 대한 모든 비용을 지불하기에 사업 타당성 판단을 위한 경제성 평가가 필수적이다. 이 연구에서는 KSO 계약 조건을 적용하여 인도네시아 소규모 광구 개발에 대한 경제성 평가를 수행하였으며, 민감도 분석을 통해 경제성 평가 시 주요 변수를 파악하였다. 그 결과 유가, CAPEX, OPEX가 경제성 평가에 영향을 미치는 것으로 나타났으며, 소규모 광구에서 상업적인 생산은 다소 어려운 것으로 판단되었다. 향후 이 연구는 국내 기업이 인도네시아 자원개발 투자 시 참고 자료로 활용할 수 있을 것이다.