• 제목/요약/키워드: viscosity measurement

검색결과 338건 처리시간 0.025초

점도 측정법을 이용한 기장(Panicum miliaceum)의 저장 중 감마선 조사 검지 가능성 (Potential Detection of γ-Irradiated Panicum miliaceum by Viscosity Measurement during Storage)

  • 최맑음;권중호;김현구
    • 한국식품영양과학회지
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    • 제32권4호
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    • pp.531-538
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    • 2003
  • 감마선 조사한 국산 및 중국산 기장의 저장 중 감마선 조사여부 획인 가능성과 품질 변화를 확인하였다 점도 측정법을 이용한 검지가능성 시험에서 시료의 점도는 조사선량에 따라 감소하였고, $0^{\circ}C$$20^{\circ}C$에서 9개월간 저장중에도 비조사구와 조사구 간의 구분이 가능하였다. Specific parameter를 설정한 결과, 조사처리에 따라 그 값이 감소하여 조사 여부의 확인이 가능하였으며, 조사선량과 specific parameter 간의 상관성은 저장 중 $r^2$가 0.92 이상으로 높게 나타나 조사 여부의 검지에 활용할 수 있을 것으로 사료된다. 한편 TBA값은 감마선 조사선량과 저장기간에 따라 유의적으로 증가하였다. Hunter color a 및 b 값은 저장기간에 상관없이 조사선량과 유의적인 상관을 나타내었다. 이상과 같이 specific parameter를 이용한 점도 측정법은 방사선 조사 후 저장 중에도 조사 여부의 screening에 적용이 가능할 것으로 판단되며, TBA값의 측정은 판정의 정확도를 높여주는 보조수단으로 기대되었다.

유압관로의 동특성을 이용한 비정상 유량계측 (Unsteady Flow Rate Measurement by Using Hydraulic Pipeline Dynamics)

  • 김도태
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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    • pp.411-416
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    • 1999
  • The measurement of unsteady flow rate is of vital importance to clarify and improve the dynamic characteristics in pipeline, hydraulic components and system. There is also demand for a real time flow sensor of ability to measure unsteady flow rate with high accuracy and fast response to realize feedback control of flow rate in fluid power systems. In this paper, we propose an approach for estimating unsteady flow rate through a pipeline and components under high pressure condition. In the method, unsteady flow rate is estimated by using hydraulic pipeline dynamics and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-checking functions of the method, the validity is investigated by comparison with the measured and estimated pressure waveforms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate waveforms and theroetical those under unsteady laminar flow conditions. the method proposed here is useful in estimating unsteady flow rate through an arbitray cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.

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경두개 도플러 초음파의 측정지표와 성/연령의 상관성 (Correlation of Gender/Age and Measurement Indices of Transcranial Doppler Ultrasonography)

  • 진복희
    • 대한임상검사과학회지
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    • 제42권3호
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    • pp.155-160
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    • 2010
  • Transcranial Doppler ultrasonography (TCD) allows measurement of blood flow velocity to be made from the basal intracerebral vessels. Blood flow velocity in TCD is highly affected not only by blood vessel diameter, blood flow volume, blood viscosity, but also age and sex. Therefore, the study is focused on the correlation between TCD measurement index and sex/age. Subjects were 214 (male 147, famale 67) who had TCD for headache and stroke evaluations at Dongguk University Ilsan Hospital neurology department from December 2009 to April 2010. Sex did not show significant differences with mean flow velocity (MFV), peak systolic flow velocity (PSFV), end diastolic flow velocity (EDFV), pulsatility index (PI) and resistance index (RI) in middle cerebral artery (MCA). Although age also did not show significant differences with MFV and PSFV, EDFV has statistically decreased with age, and PI and RI has statistically increased with age. In addition, age showed significant correlation with MFV, EDFV, PI and RI, but not with PSFV. Therefore, TCD is definitely correlated with age and sex, so that those influencial factors must be considered when being tested.

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연료의 물성치 변화가 이중 오리피스 연료 노즐의 분무 구조에 미치는 영향에 관한 연구 (A Effect of Fuel Properties on Spray Structure for Dual Orifice Fuel Injector)

  • 이동훈;최성만;박정배
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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    • pp.179-188
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    • 2003
  • The spray characteristics of dual orifice injector were investigated under two different fuels through measurement of SMD, number density and volume flux by using PDPA system. In this experiment, we found out that the droplet size and spray structure are strongly depend on fuel density and viscosity.

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Organic Solvent Absorption characteristics of Split-type micro fiber fabrics

  • Lee, Kwang-Ju;Kim, Seong-Hun
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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    • pp.95-95
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    • 2003
  • In this study, the influences of organic solvent viscosity on absorption properties of split-type micro fiber fabrics is examined with real time absorption measurement device built by our research group recently. And the absorption behavior of these fabrics is analyzed by material, fineness, construction, weight, thickness, and density of fabrics.

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산화성 분위기에서 석탁회분 슬래그의 고온 점도 측정 (High Temperature Viscosity Measurement of Coal Ash Slags in Oxidizing Atmosphere)

  • 정봉진
    • 에너지공학
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    • 제4권3호
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    • pp.324-330
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    • 1995
  • 석탄 연소로에 사용 적합한 석탄의 선정 및 조업조건의 설정에 도움을 주고, 석탁회분의 슬래깅 성향을 파악하기 위해서 갈탄부터 역청탄에 이르는 4종의 시료를 사용하여 산화성 분위기에서 고온 회전 점도계를 사용하여 석탄회분 슬래그의 점도를 온도의 함수로서 측정하였다. 또한 석탄회분의 슬래깅 성향을 해석하기 위해서, 석탄회분 조성을 사용한 Base/Acid Ratio, Lignite Factor 및 Silica Ratio 등의 주요한 인자들이 슬래그 점도에 미치는 영향을 고찰하였다.

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박판성형 해석용 수학적 마찰 모델 (Mathematical Friction Model for Sheet Metal Forming Analysis)

  • 금영탁;송민재
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 춘계학술대회 논문집
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    • pp.182-185
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    • 2004
  • Based on the experimental observation, the mathematical friction model, which is an essential information for analyzing the forming process of sheet metal, is developed considering lubricant viscosity, surface roughness and hardness, punch corner radius, and punch speed. By comparing the punch load found by FEM with a proposed friction model with experimental measurement when the coated and uncoated steel sheets are formed in 2-D geometry in dry and lubricant conditions, the validity and accuracy of the developed friction model are demonstrated.

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광물질 혼화재를 혼합한 모르타르의 유변학적 특성 (Rheology properties of mortar using mineral admixture)

  • 김용직;김영진;최연왕
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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    • pp.341-342
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    • 2010
  • 본 연구는 광물질혼화재를 사용한 모르타르의 유변학적 특성을 검토하였다. 검토 항목으로는 모르타르의 점도, 항복값 및 재령별 압축강도를 측정하여 검토하였다.

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The Novel Liquid Crystal Materials for AM-LCDs

  • Yamaguchi, T.;Kibe, S.;Matsui, S.;Yamamoto, H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.924-929
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    • 2002
  • We have developed the novel liquid crystal materials with a difluoromethyleneoxy (CF2O) moiety as a linkage group in order to satisfy the diversified various requirements for AM-LCDs. These novel CF2O LC materials have excellent physical properties that are high dielectric anisotropy, low viscosity and wide nematic temperature ranges. Physical properties measurement results that mixtures containing CF2O LC materials have suitable for characteristics for AM-LCDs. The CF2O LC materials are excellent compound for quick response and low driving voltage application.

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박판성형 해석용 마찰 모델(2부:수학적 모델) (Friction Model for Sheet Metal Forming Analysis(Part 2 :Mathematical Model))

  • 금영탁;이봉현
    • 소성∙가공
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    • 제13권5호
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    • pp.461-465
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    • 2004
  • Based on the experimental observation, the mathematical friction model, which is an essential information for analyzing the forming process of sheet metal, is developed considering lubricant viscosity, surface roughness and hardness, punch comer radius, and punch speed. By comparing the punch load found by FEM with a proposed friction model with experimental measurement when the coated and uncoated steel sheets are formed in 2-D geometry in dry and lubricant conditions, the validity and accuracy of the developed friction model are demonstrated.