• 제목/요약/키워드: BDF 10

검색결과 39건 처리시간 0.023초

AN OVERVIEW OF BDF2 GAUGE-UZAWA METHODS FOR INCOMPRESSIBLE FLOWS

  • Pyo, Jae-Hong
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제15권3호
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    • pp.233-251
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    • 2011
  • The Gauge-Uzawa method [GUM] in [9] which is a projection type algorithm to solve evolution Navier-Stokes equations has many advantages and superior performance. But this method has been studied for backward Euler time discrete scheme which is the first order technique, because the classical second order GUM requests rather strong stability condition. Recently, the second order time discrete GUM was modified to be unconditionally stable and estimated errors in [12]. In this paper, we contemplate several GUMs which can be derived by the same manner within [12], and we dig out properties of them for both stability and accuracy. In addition, we evaluate an stability condition for the classical GUM to construct an adaptive GUM for time to make free from strong stability condition of the classical GUM.

Optimal Allocation of Distributed Solar Photovoltaic Generation in Electrical Distribution System under Uncertainties

  • Verma, Ashu;Tyagi, Arjun;Krishan, Ram
    • Journal of Electrical Engineering and Technology
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    • 제12권4호
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    • pp.1386-1396
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    • 2017
  • In this paper, a new approach is proposed to select the optimal sitting and sizing of distributed solar photovoltaic generation (SPVG) in a radial electrical distribution systems (EDS) considering load/generation uncertainties. Here, distributed generations (DGs) allocation problem is modeled as optimization problem with network loss based objective function under various equality and inequality constrains in an uncertain environment. A boundary power flow is utilized to address the uncertainties in load/generation forecasts. This approach facilitates the consideration of random uncertainties in forecast having no statistical history. Uncertain solar irradiance is modeled by beta distribution function (BDF). The resulted optimization problem is solved by a new Dynamic Harmony Search Algorithm (DHSA). Dynamic band width (DBW) based DHSA is proposed to enhance the search space and dynamically adjust the exploitation near the optimal solution. Proposed approach is demonstrated for two standard IEEE radial distribution systems under different scenarios.

A Chebyshev Collocation Method for Stiff Initial Value Problems and Its Stability

  • Kim, Sang-Dong;Kwon, Jong-Kyum;Piao, Xiangfan;Kim, Phil-Su
    • Kyungpook Mathematical Journal
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    • 제51권4호
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    • pp.435-456
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    • 2011
  • The Chebyshev collocation method in [21] to solve stiff initial-value problems is generalized by using arbitrary degrees of interpolation polynomials and arbitrary collocation points. The convergence of this generalized Chebyshev collocation method is shown to be independent of the chosen collocation points. It is observed how the stability region does depend on collocation points. In particular, A-stability is shown by taking the mid points of nodes as collocation points.

균열손상 후 동결융해를 경험한 철근콘크리트 보의 휨거동 (Effect of Freeze-Thaw Cycles after Cracking Damage on the Flexural Behavior of Reinforced Concrete Beams)

  • 김선우;최기봉;윤현도
    • 콘크리트학회논문집
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    • 제22권3호
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    • pp.399-407
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    • 2010
  • 이 연구에서는 동결융해 사이클을 경험한 2가지 종류의 휨부재의 거동특성을 평가하였다. 이 연구의 목적은 동결융해에 따른 철근콘크리트 보의 거동특성을 검토하는 것이다. 이를 위해 일부 실험체는 동결융해를 경험하기 전, 인장철근이 항복되기까지 손상을 입도록 계획되었다. 또한 반복하중 재하시 강성저하 특성을 평가하기 위하여 단조 및 반복재하 실험을 실시하였다. 재료 실험 결과, 동결융해 300사이클을 경험한 콘크리트의 상대동탄성계수는 86.8%까지 감소되었으나 내동해저항성은 충분히 가지고 있는 것으로 평가되었다. 단조재하 실험 결과, 동결융해 사이클에 따른 휨 강도, 연성 및 강성은 상대적으로 감소하는 것으로 나타났다. 특히, 인위적 균열손상을 경험한 BDF13 시리즈는 현행 콘크리트설계기준에서 요구하는 공칭모멘트를 만족하지 못하는 것으로 나타났다. 반복재하시 BF75 시리즈에서 동결융해를 경험함에 따라 10% 이상의 반복강성 저하를 나타내었다. 따라서 내진부재와 같이 반복하중을 받게 되는 부재를 설계할 경우, 동결융해로 인한 압축측 콘크리트의 변형 특성도 고려되어야 할 것으로 판단된다.

흰쥐 베타-카제인 유전자의 발현조절 부위를 이용하여 유선에서 사람 락토페린을 발현하는 형질전환 생쥐의 개발 (Expression of Human Lactoferrin in the Mammary Glands of Transgenic Mice using Regulatory Elements of Rat $\beta$-Casein Gene)

  • 김선정;이고운;배수경;조용연;한용만;이철상;이경광;유대열
    • 한국가축번식학회지
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    • 제18권2호
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    • pp.133-139
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    • 1994
  • Two human lactoferrin expression vectors(pCChcLf and pCChcLf-1) were constructed using rat $\beta$-casein gene and human lactoferrin cDNA. The recombinant DNAs containing human lactoferrin cDNA were microinjected into the fertilized eggs of hybrid mice (BDF1 : C57BL$\times$DBA) and the DNA-injected eggs were treansferred into the oviducts of foster mothers. Genomic DNAs were isolated from the tails of mice born from the microinjected eggs and analyzed by Southern blot analysis. As a result, 5 and 9 transgenic mice with CChcLf and CChcLf-1 gene were produced, respectively. To determine tissue-specificity of transgene expression, Northern blot analysis was performed. Female transgenic mice were killed at day 10 of lactation and total RNAs from various tissues were isolated. Based on Northern blot analysis, it was shown that transgene was mainly expressed in the mammary glands of transgenic mice. In addition, the human lactoferrin in milk was detected by enzyme-linked immunosorbent assay. For this study, milk was obtained from the mammary glands of the transgenic mice at day 10 of lactation. In line #2 of CChcLf and line #7 of CChcLf-1 transgenic mice, human lactoferrin was secreted into the milk at concentration levels of 340ng/ml and 60ng/ml, respectively.

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디젤기관에서 바이오디젤 연료가 배기배출물 특성에 미치는 영향(대두유를 중심으로) (Effects of Biodiesel Fuel on Exhaust Emission Characteristics in Diesel Engine(Using Soybean Oil))

  • 임재근;최순열;조상곤
    • Journal of Advanced Marine Engineering and Technology
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    • 제32권1호
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    • pp.27-32
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    • 2008
  • Recently, we have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodisel was produced from soybean oil at our laboratory. This study showed that Soot and CO emission were decreased as the blending ratios of biodiesel to diesel oil increased, on the other hand NOx emission was slightly increased because of the oxygen content in biodiesel. Also, the biodiesel blends yielded slightly higher specific fuel consumption than that of diesel oil because of lower heating value of biodiesel.

직접분사식 디젤기관에서 바이오디젤유와 함산소성분 혼합연료 적용시 배기배출물 특성 및 EGR의 적용 연구 (A Study on Emission Charncteristics and EGR Application of Blending Fuels with Biodiesel Fuel and Oxygenate Component in a D.I. Diesel Engine)

  • 최승훈;오영택
    • 한국자동차공학회논문집
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    • 제16권2호
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    • pp.43-48
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    • 2008
  • The exhaust emissions of diesel engine are recognized as a major cause influencing environment strongly. In this study, the possibility of biodiesel fuel and oxygenated fuel(dimethoxy methane; DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel(biodiesel fuel 90vol-%+DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load, in comparison with the diesel fuel. But, power, torque and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counterplan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF(95 vol-%) and DMM(5 vol-%) blended fuel and cooled EGR method(15%).

공공기관 소방안전관리 실태조사를 통한 개선방안에 관한 연구 : 초·중등학교를 중심으로 (An Improvement Plan on Fire Safety Management of Public Institutions: Focusing on the Case of Elementary and Secondary Schools)

  • 한상필
    • 한국화재소방학회논문지
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    • 제34권3호
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    • pp.85-90
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    • 2020
  • 본 연구는 공공기관의 소방안전관리실태를 파악, 분석하여 위험요소에 대한 철저한 예방과 화재상황에 대한 신속한 대응 체제가 구축될 수 있는 초·중등학교 소방안전관리 개선방안을 모색, 강구하는 것이 목적이다. 현재 강원도 내 초·중등학교에 소방안전관리자로 선임된 인원을 대상으로 소방안전관리자의 전문성, 예방능력, 대비능력, 운영형태 등을 설문을 통해 조사하여 분석하였다. 실태조사 문항은 26개 항목으로 구성하였다. 그 결과, 소방안전관리에 대한 인식은 상당히 높은 반면에 사고를 대비, 대응할 수 있는 소방안전관리자의 능력은 제도적, 기술적 측면에서 개선되어야 하는 것으로 파악되었다.

Effects of supplementation with antifreeze proteins on the follicular integrity of vitrified-warmed mouse ovaries: Comparison of two types of antifreeze proteins alone and in combination

  • Kim, Min Kyung;Kong, Hyun Sun;Youm, Hye Won;Jee, Byung Chul
    • Clinical and Experimental Reproductive Medicine
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    • 제44권1호
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    • pp.8-14
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    • 2017
  • Objective: The aim of this study was to analyze the effect of supplementing vitrification and warming solutions with two types of antifreeze proteins (AFPs) and the combination thereof on the follicular integrity of vitrified-warmed mouse ovaries. Methods: Ovaries (n=154) were obtained from 5-week-old BDF1 female mice (n=77) and vitrified using ethylene glycol and dimethyl sulfoxide with the supplementation of 10 mg/mL of Flavobacterium frigoris ice-binding protein (FfIBP), 10 mg/mL of type III AFP, or the combination thereof. Ovarian sections were examined by light microscopy after hematoxylin and eosin staining, and follicular intactness was assessed as a whole and according to the type of follicle. Apoptosis within the follicles as a whole was detected by a terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay. Results: The proportion of overall intact follicles was significantly higher in the type III AFP-supplemented group (60.5%) and the combination group (62.9%) than in the non-supplemented controls (43.8%, p<0.05 for each). The proportion of intact primordial follicles was significantly higher in the FfIBP-supplemented (90.0%), type III AFP-supplemented (92.3%), and combination (89.7%) groups than in the non-supplemented control group (46.2%, p<0.05 for each). The proportions of non-apoptotic follicles were similar across the four groups. Conclusion: Supplementation of the vitrification and warming solutions with FfIBP, type III AFP, or the combination thereof was equally beneficial for the preservation of primordial follicles in vitrified mouse ovaries.

쉬땅나무(Sorbaria sorbifolia) 성분으로서 cucurbitacin D, F의 독성평가 및 정량 (Toxic Evaluation and Chromatographic Analysis of Cucurbitacin D and F from Sorbaria sorbifolia)

  • 이상명;이철규
    • 분석과학
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    • 제14권2호
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    • pp.191-195
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    • 2001
  • Sorbaria sorbifolia의 다양한 추출 및 정제방법에 의하여 protostane계 triterpenoid인 cucurbitacin D, F를 분리하여 그를 표준품으로 하여 S. sorbifolia에 함유된 cucurbitacin D, F를 정량하였다. 표준품으로서 cucurbitacin D, F는 $^1H$-NMR, FAB-MS, UV 등 각종 물리화학적자료에 의하여 구조 동정하였으며 그들은 YMC-Pack ODS-AQ(303)[$250{\times}4.6mm$ I.D., $S-5{\mu}m$, 120A]을 칼럼으로 사용한 고속액체 크로마토그래피에 의하여 분리하였다. Cucurbitacin D, F의 액체크로마토그래피에 의한 정량 분석 결과 cucurbitacin F의 경우 S. sorbifolia 시료에 10.73mg/kg으로 존재하였으나 cucurbitacin D는 검출되지 않았다. 또한 각종 암세포주에서 평균 $ED_{50}$값이 $0.1{\mu}g/mL$ 이하로서 강한 세포독성을 보였으며 이 두 화합물을 생쥐의 복강에 투여하였을 때 $LD_{50}$값은 각각 4.7, 2.5mg/kg/day로서 심한 급성독성을 나타내었다.

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