• 제목/요약/키워드: Differential Apparatus

검색결과 59건 처리시간 0.025초

적혈구 변형성의 측정과 혈액 점도와의 상관관계 연구 (Measurements of RBC deformability and its effect on blood viscosity)

  • 구윤희;박명수;신세현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1682-1686
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    • 2004
  • A slit-flow apparatus with laser diffraction method has been developed with significant advances in ektacytometry design, operation and data analysis. In the slit-flow ektacytometry (or laser-diffractometry), the deformation of red blood cells subjected to continuously decreasing shear stress in slit flow is measured. A laser beam traverses a diluted blood suspension flowing through a slit and is diffracted by RBCs in the volume. The diffraction patterns are captured by a CCD-video camera, linked to a frame grabber integrated with a computer, while the differential pressure variation is measured by a pressure transducer. Both measurements of laser-diffraction image and pressure with respect to time enable to determine deformation index and the shear stress. The range of shear stress of 0 ${\sim}$ 35 Pa and measuring time is less than 2 min. When deforming under decreasing shear stress, RBCs change gradually from the prolate ellipsoid towards a circular biconcave morphology. The Deformation Index (DI) as a measure of RBC deformability is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The advantages of this design are simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is contacted with blood sample.

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일정전류 비평행교류브릿지에 의한 전도도측정과 황의 정량 (An Unbalanced A.C. Bridge with High Voltage Source for the Conductometric Determination of Sulfur in Iron Ores)

  • 채명준;최규원
    • 대한화학회지
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    • 제14권4호
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    • pp.327-332
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    • 1970
  • A simple and convenient device for deflection-type direct reading the variations in electrolytic conductance is described and applied to the analysis of sulfur by combustion-$H_2O_2$ oxidation method. The apparatus consisted of a high resistance-ratio bridge in which the other adjacent arms are the differential cells. By adopting unusually high a-c voltage source for the bridge excitation, the a-c method for unbalanced bridge is established, decreased sensitivity owing to reduced bridge factor, 0.01, is overcome and also the absolute sensitivity and linearity are greatly improved. Over 50% variations in impedance of the balanced cell, within 1% deviation from the linearity can be attained with a volt (rms)order of output which was detected directly with VTVM without further amplification. Analysis of the bridge shows that these useful features are natural result of the constant current character of the high source impedance generator and the performance of the device agreed with the theoretical predictions. A standard procedure for the rapid analysis of sulfur using the bridge is also given, the analytical accuracy was approximately 1%. A determination takes not more than 5 minutes.

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Nondestructive Evaluation of Residual Life of 1Cr-1Mo-0.25V Steel by Reversible Magnetic Permeability

  • K. S. Ryu;S. H. Nahm;Kim, Y. I.;K. M. Yu;Kim, Y. B.;Y. Cho;D. Son
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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    • pp.522-529
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    • 2000
  • We present a new procedure to evaluate the residual life of 1Cr-1Mo-0.25V steel by reversible magnetic permeability. The method is based on the existence of the first harmonics in the differential magnetization around the coercive force. The apparatus is based on the detection of the voltage induced in a coil using a lock-in amplifier tuned to a frequency of the exciting one. Results obtained for the first harmonics and Vickers hardness on the aged samples show that the peak interval of reversible permeability and Vickers hardness decrease as ageing time increases. The correlation between Vickers hardness and the peak interval of the reversible permeability could well be used to evaluate the residual life of 1Cr-1Mo-0.25V steel, nondestructively.

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(H2O-Piperidine-CO2) system에서 piperidine 유도체의 작용기 위치에 따른 이산화탄소 흡수특성 연구 (The Effect of Functional Group Position of the Piperidine Derivatives on the CO2 Absorption Characteristics in the (H2O-Piperidine-CO2) System)

  • 최정호;윤성희;김영은;윤여일;남성찬
    • Korean Chemical Engineering Research
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    • 제53권1호
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    • pp.57-63
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    • 2015
  • 본 연구에서는 기-액 평형장치와 반응열 측정장치를 이용하여 2-methylpiperidine (2MPD), 3-methylpiperidine (3MPD), 4-methylpiperidine (4MPD) 흡수제의 이산화탄소 흡수특성을 연구하였다. 기-액 평형장치를 이용하여 각 흡수제의 이산화탄소 흡수능을 알아보았고, 흡수평형 후의 흡수액을 핵자기공명장치(nuclear magnetic resonance spectroscopy: NMR)로 분석하여 종 형성을 확인하였다. 추가적으로 반응열 측정장치를 이용하여 흡수능에 따른 반응열을 제시하였다. 실험결과 2MPD, 3MPD, 4MPD 흡수제는 작용기 위치에 따라 다른 특성을 나타내었다. Ortho 위치에 메틸기를 가진 2MPD는 입체장애효과로 인하여 흡수반응에서 특이성이 나타났으나 3MPD와 4MPD는 ($H_2O$-piperidine-$CO_2$) 시스템에서 반응 특이성이 나타나지 않았다.

액상화 후 잔류전단변형률이 체적변형률과 유효응력 관계에 미치는 영향 (Effect of Residual Shear Strain on the Relationship between Volumetric Strain and Effective Stress after Liquefaction)

  • 권영철
    • 한국지반환경공학회 논문집
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    • 제11권11호
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    • pp.55-62
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    • 2010
  • 액상화에 의해 발생되는 피해의 상당 부분은 반복전단과정에서 발생한 과잉간극수압이 소산되면서 지표에 나타나는 침하에서 유발된다. 그러나 지반은 매우 복잡한 구조로 되어 있기 때문에 침하는 균등하게 발생하지 않으며 대부분 부등 침하의 형태로 발생되게 된다. 일반적으로는 이러한 잔류전단변형률이 없는 상태에서 재압밀을 수행하지만 현실적으로는 잔류전단변형이 남아있는 것이 자연스러운 현상이라는 인식과 함께 다양한 다이레이턴시 특성하에서 발생되는 액상화 후 재압밀에 대한 고찰이 거의 이루어지지 않았다는 점에 주목하여 본 연구에서는 잔류전단변형률이 액상화 후 재압밀과정에 미치는 영향을 검토하였다. 이를 위하여 변형률 제어에 기반을 둔 시험장치와 간극수의 배수를 정밀 제어할 수 있는 체적변형률 제어장치를 이용하여 세립분을 포함하고 있지 않은 표준사와 세립분을 포함한 풍화토에 대한 일련의 삼축압축시험을 실시하였고 그 결과를 고찰하였다. 결과 표준사의 경우 에는 상대적으로 잔류전단변형률이 액상화 후 체적압축특성에 미치는 영향이 작았으나 풍화토의 경우에는 유효응력-체적변형률 관계곡선이 잔류전단변형률이 클수록 하방에 위치하였으며 곡선의 형상에도 영향을 미치고 있었고 대체적으로 응력 수준이 낮은 배수 초기에 체적변형률이 급증하며 유효응력 증가에도 거의 체적변형은 일어나지 않고 있다. 액상화에 의한 침투유동파괴가 낮은 응력 수준에서 발생된다는 점을 고려하면 이러한 관계 곡선의 형상은 매우 중요한 의미를 갖는다.

Identification of Differentially Expressed Genes Related to Intramuscular Fat Development in the Early and Late Fattening Stages of Hanwoo Steers

  • Lee, Seung-Hwan;Park, Eung-Woo;Cho, Yong-Min;Kim, Sung-Kon;Lee, Jun-Heon;Jeon, Jin-Tae;Lee, Chang-Soo;Im, Seok-Ki;Oh, Sung-Jong;Thompson, J.M.;Yoon, Du-Hak
    • BMB Reports
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    • 제40권5호
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    • pp.757-764
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    • 2007
  • Marbling of cattle meat is dependent on the coordinated expression of multiple genes. Cattle dramatically increase their intramuscular fat content in the longissimus dorsi muscle between 12 and 27 months of age. We used the annealing control primer (ACP)-differential display RT-PCR method to identify differentially expressed genes (DEGs) that may participate in the development of intramuscular fat between early (12 months old) and late fattening stages (27 months old). Using 20 arbitrary ACP primers, we identified and sequenced 14 DEGs. BLAST searches revealed that expression of the MDH, PI4-K, ferritin, ICER, NID-2, WDNMI, telethonin, filamin, and desmin (DES) genes increased while that of GAPD, COP VII, ACTA1, CamK II, and nebulin decreased during the late fattening stage. The results of functional categorization using the Gene Ontology database for 14 known genes indicated that MDH, GAPD, and COP VII are involved in metabolic pathways such as glycolysis and the TCA cycle, whereas telethonin, filamin, nebulin, desmin, and ACTA1 contribute to the muscle contractile apparatus, and PI4-K, CamK II, and ICER have roles in signal transduction pathways regulated by growth factor or hormones. The final three genes, NID-2, WDNMI, and ferritin, are involved in iron transport and extracellular protein inhibition. The expression patterns were confirmed for seven genes (MDH, PI4-K, ferritin, ICER, nebulin, WDNMI, and telethonin) using real-time PCR. We found that the novel transcription repressor ICER gene was highly expressed in the late fattening stage and during bovine preadipocyte differentiation. This information may be helpful in selecting candidate genes that participate in intramuscular fat development in cattle.

복합산화물 촉매 상에서 메탄의 부분산화에 의한 메탄올 및 포름알데히드의 합성 (Synthesis of Methanol and Formaldehyde by Partial Oxidation of Methane over Mixed Oxide Catalysts)

  • 함현식;신기석;안성환;김송형;홍석영;박홍수
    • 한국응용과학기술학회지
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    • 제23권3호
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    • pp.223-229
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    • 2006
  • Methanol and formaldehyde were produced directly by the partial oxidation of methane over mixed oxide catalysts. The catalysts were composed of Mo and Bi with late-transition metals, such as Mn, Fe, and Co. The reaction was carried out at $450^{\circ}C$, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by $O_2-TPD$ and BET apparatus. Among the catalysts used, the catalyst composed of 1:1:2.5 molar ratio of Mo:Bi:Mn showed the best methane conversion and methanol selectivity. The change in ratio of methane to oxygen affected at the conversion and selectivity, and the most proper ratio was 10:1.5. Methane conversion, methanol and formaldehyde selectivities increased with the surface areas of the catalysts. From the $O_2-TPD$ result, it was found that the oxygen species responsible for this reaction might be the lattice oxygen species desorbed at high temperature around $800^{\circ}C$.

지환족 다이안하이드라이드를 포함하는 용해성 폴리이미드의 기체투과특성 (Gas Transport Properties of Soluble Polyimides Containing Alicyclic Dianhydride)

  • 김은희;박채영;김정훈
    • 멤브레인
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    • 제24권2호
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    • pp.100-106
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    • 2014
  • 본 연구에서는 용해성 폴리이미드 합성을 위해 지환족(alicyclic) dianhydride 단량체인 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA)와 diamine으로는 4,4'-diaminodiphenylether (ODA), 1,4-phenylenediamine (p-PDA)를 사용하여 두 가지 폴리이미드를 제조한 후 그 특성을 고찰하고 기체투과특성을 알아보았다. 제조된 폴리이미드는 FT-IR을 통해 합성이 성공적으로 이루어졌음을 확인하였고 DSC를 통하여 열적 안정성을 알아보았다. 제조된 폴리이미드막의 $CH_4$$CO_2$에 대한 기체투과계수(P)와 이상 선택도는 time-lag 장비로 측정하였다. 그 결과, DOCDA-ODA, DOCDA-p-PDA의 경우 $CO_2$의 투과도는 각각 6.10, 0.74 barrer로 나타났고 $CO_2/CH_4$의 선택도는 67.03, 46.25의 결과를 나타내었다. 두 가지 폴리이미드 중 DOCDA-ODA의 경우 폴리이미드 재료의 특성인 우수한 투과도 및 선택도로 새로운 기체분리막으로서의 이용가능성을 나타내었다.

지면의 상태에 따른 요부안정화운동 적용 시 산업체 근로자의 심혈관기능 변화 (Change of Cardiovascular Function of Industrial Workers Apply to Lumbar Stabilization Exercise according to the Floor Type)

  • 김찬규;채윤원;김명훈;이정훈;고대식;정대인
    • 한국콘텐츠학회논문지
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    • 제9권7호
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    • pp.225-232
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    • 2009
  • 연구는 심박수, 수축기 혈압, 이완기 혈압, 말초혈관 산소포화도 알아보고자 바닥과 스위스 볼상에서 요부안정화운동(LSE)에 따른 심혈관기능에 미치는 연구를 하였다. 대상자는 K 산업체 재활센타를 이용한 근골격계 근로자 중 선정기준에 적합한 남성 18명을 실험1군 바닥 적용군에 9명, 실험군 2군 스위스볼 적용군에 9명으로 분류하여 심박수, 수축기 혈압, 이완기 혈압, 말초혈관 산소포화도를 비교하였다. 심박수는 휴대용 심박 측정계(RS400sd, Finland)로, 혈압은 혈압계((FC-110, Japan)로, 말초혈관 산소포화도는 누리텍 체력 측정장치((TF-300-5, Korea)로 측정하고 분석하였다. 두군 모두 운동실시 후에 말초혈관 산소농도가 점차 통계학적으로 유의하게 증가하였으며, 수축기혈압이 통계학적으로 유의하게 감소하였다. 요부안정화운동에 따른 자세변동이 심혈관기능에 영향을 미치지만 지변의 상태에 따른 차이는 크게 영향을 받지 않는다는 결론을 얻었다.

메탄의 부분산화에 의한 메탄올 및 포름알데히드의 합성 (Synthesis of Methanol and Formaldehyde by Partial Oxidation of Methane)

  • 함현식;신기석;김송형;안성환;김명수;박홍수
    • 한국응용과학기술학회지
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    • 제23권1호
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    • pp.63-69
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    • 2006
  • Methanol and formaldehyde were produced directly by the partial oxidation of methane. The catalysts used were mixed oxides of late-transition metals, such as Mn, Fe, Co, Ni and Cu. The reaction was carried out at $450^{\circ}C$, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by XRD, TPD and BET apparatus. Of the catalysts, A-Mn0.2-6, which contains 0.2 mole of Mn and calcined at $600^{\circ}C$, showed the best catalytic activity: 3.7% methane conversion, and 30 and 28% methanol and formaldehyde selectivities, respectively. The catalytic activity was changed with the content of Mn and the calcination temperature. Catalytic activity increased with the specific surface areas of the catalysts. With XRD, it was found that the structure of the catalysts are changed with calcination temperature. Through $O_2-TPD$ experiment, it was found that the catalysts showing good catalytic activity showed $O_2$ desorption peak around $800^{\circ}C$.