• 제목/요약/키워드: Transition region

검색결과 956건 처리시간 0.024초

액체배관으로부터 위험물질 누출속도 산정에 관한 연구 (A Study on the Release Rate of Hazardous Materials from Liquid Pipeline)

  • 탁송수;조영도
    • 한국가스학회지
    • /
    • 제6권1호
    • /
    • pp.81-85
    • /
    • 2002
  • 탱크와 연결된 배관에서 원하지 않은 사고로 인해 액체 위험물질의 누출이 발생할 경우 천이영역에서의 누출속도 계산방법을 제시하였다. 배관에서의 액누출에 관한 누출속도는 층류와 난류영역에서 Crowl and Louvar 등이 제시한 모델식을 이용하여 프로그램 또는 직접계산에 의해 이루어지고 있으나, 천이영역에 대한 모델식은 없었다. 따라서 본 논문에서는 Lap-Mou Tam 등이 실험한 천이영역에서 레이놀즈수에 따른 마찰계수 실험값을 이용하여 천이영역에 대한 누출속도 값을 계산하였고 이 값을 층류와 난류에 관한 모델식을 사용한 값과의 비교를 통해 천이영역에서 일반적으로 사용할 수 있는 모델식으로 난류에 관한 모델식으로 계산한 값에 안전율 $30\%$를 추가한 값을 위험평가에 사용할 수 있음을 보였다.

  • PDF

Chain Dimensions and Intrinsic Viscosities of Polypeptides in the Helix-Coil Transition Region

  • Jong-Ryul Kim;Tai-Kyue Ree
    • Bulletin of the Korean Chemical Society
    • /
    • 제4권1호
    • /
    • pp.36-41
    • /
    • 1983
  • An equation is derived which correlates the unperturbed dimensions $_0$ of polypeptides with the helical contents in the helix-coil transition region by using a simple model of a polypeptide chain. The model is a chain of connected balls which represent the repeating units, -CO-NH-CHR-, based on the fact that the repeating unit has a plane structure. The changing trend of the expansion factor ${\alpha}_{\eta}$ in the transition region is connected with the helical content $f_H$. The intrinsic viscosities [${\eta}$] of polypeptides are calculated from the unperturbed dimensions and the ${\alpha}_{\eta}$ factors. The above calculated results concerning $_0$ and [${\eta}$] are compared with other authors' theoretical and experimental results. From the comparison, we concluded that our theory explains better the chain dimensional behavior of polypeptides in the helix-coil transition region than others.

대두(Glycine max) 유식물에서 하배축의 신장과 유관속전이 (Vascular Transition and Hypocotyl Elongation in Soybean(Glycin max) Seedlings)

  • 강경덕
    • Journal of Plant Biology
    • /
    • 제34권4호
    • /
    • pp.274-281
    • /
    • 1991
  • The relationship between elongation of hypocotyl and its vascular transition was studied with seedling of Glycine max. the hypocotyl elongation proceeded acropetally from the base of hypocotyl toward the cotyledonary node. The vascular transition did not occur in the basal region of the hypocotyl, which did not nearly elongate, with exarch radial vascular bundles. However, the vascular transition was almost completed at the middle part of the hypocoty, more or less elongated, with endarch collateral vascular bundles. Such bundles also appeared in the uppermost region of the hypocotyl, in which the elongation was the most striking. These results suggested that the vascular transition was related to the hypocotyl elongation and that the transition of primary vascular system in Glycine max seedling was established by rather rapid process. Our observations of the serial sections from root to hypocotyl revealed that the vascular system through the root-hypocotyl-cotyledon was a unit, to which one of the epicotyl that did not participate in transition was superimposed.

  • PDF

3Cr-1Mo강/STS-309L 오버레이 용접부의 천이영역 조직에 미치는 용접조건의 영향 (Effect of Welding Condition on Microstructure of Transient Zone in Overlay Weld of 3Cr-1Mo Steel/STS-309L)

  • 김동진;김병훈;지병하;김정태;김성곤;강정윤;박화순
    • Journal of Welding and Joining
    • /
    • 제18권2호
    • /
    • pp.49-56
    • /
    • 2000
  • Recently developed Austenite stainless steel, 309L was used to overlay on 3Cr-1Mo-V-Ti-B steels, using Electroslag welding process, which wide electrodes were adopted. Transition region in welding interlayer relating to disbonding crack was investigated. Also, the effect of welding condition on the width of transition region and coarsening grains of the austenite were studied. 1) With increasing welding speed the width of martensite at transient region was increased, but the amount of delta ferrite in weld metal was reduced, being fine grained. 2) The form of martensite at the transition region was occurred by reversible transformation during cooling since the interdiffusion of Cr and Ni from weld metal and Fe and C from base metals at the transition region, causes to lowering the concentration of Cr and Ni at the transition region, leading to increasing Ms point. 3) With increasing welding speed, the grain of austenite formed at the welding interface was finer. With increasing welding current under the same welding speed, the grain size of the austenite was finer. At high current, original grain size of the austenite is coarse, but the austenite has fine grains because the austenite was transformed to martensite during cooling. 4) In the case of high welding speed, the width of martensite at the welding interface was increased, but the grain size of austenite at the welding interface was finer. This indicates that the inhibition of disbonding crack may be achieved through dispersening fine carbides in the gain boundary.

  • PDF

인물 면적을 이용한 갈등 전환 장면 검출 (Detection of Conflict Transition Scene Using Character Regions)

  • 박승보;이창현
    • 방송공학회논문지
    • /
    • 제26권5호
    • /
    • pp.543-552
    • /
    • 2021
  • 스토리는 인물들 간의 갈등의 전개와 해소의 흐름에 의해 형성된다. 갈등의 설정, 전개, 해결의 흐름이 스토리이다. 인물 면적은 인물의 감정 또는 상태, 인물 간 관계인물과 환경과의 관계를 묘사하는 중요한 표현 기법이다. 본 논문은 인물 면적의 변화 그래프로부터 갈등의 전환 지점을 검출하는 방법을 제안하는 것이 목적이다. 이를 위해 인물 면적을 계산하여 영화의 인물 면적 변화 그래프를 생성하는 방법과 인물 면적 변화 그래프로부터 갈등 전환 장면을 검출하는 방법을 제시한다. 제안하는 방법의 성능을 검증하기 위해 7개의 영화에 대해 갈등 전환 장면을 추출하는 실험을 진행하여 정확도 73.57%, 재현율 77.26%의 성능 평가 결과를 얻었다. 이를 통해 인물 면적에 기반하여 갈등 전환 장면을 추출하는 것이 가능하다는 것을 증명하였다.

DCT계수와 천이지도 분석을 이용한 개선된 영상 내 자막영역 검출방법 (An Improved Method for Detecting Caption in image using DCT-coefficient and Transition-map Analysis)

  • 안권재;주성일;김계영;최형일
    • 한국컴퓨터정보학회논문지
    • /
    • 제16권4호
    • /
    • pp.61-71
    • /
    • 2011
  • 본 논문은 DCT계수와 천이지도 분석을 이용하여 영상 내 자막영역을 검출하는 방법에 대해 제안한다. 기존 DCT계수 분석방법을 이용한 문자영역탐지 방법은 검출률은 높으나 오검출률이 매우 높은 단점이 있고, 천이지도를 이용한문자영역 탐지 방법은 임계값이 정적이기때문에 문자영역 검증단계에서 실제문자영역이 기각되는 일이 빈번히 발생한다. 이러한 문제점을 해결하기 위해 DCT계수 분석방법을 이용하여 유망문자영역맵을 작성하고 이를 천이지도를 이용한 문자영역탐지 방법에 적용하여 임계값을 단계별로 정한다. 그 결과로서 DCT계수 분석을 이용한 문자영역검출방법에 비해 오검출률이 크게 감소하였으며, 기존 천이지도를 이용한 문자영역검출 방법보다 검출률이 크게 향상되었다.

Analysis of Two-Dimensional Flow Fields in the Multi-Stage Turbomolecular Pump Using the DSMC Method

  • Heo, Joong-Sik;Hwang, Young-Kyu
    • International Journal of Air-Conditioning and Refrigeration
    • /
    • 제9권2호
    • /
    • pp.8-18
    • /
    • 2001
  • The direct simulation Monte Carlo Method is applied to investigate the two-dimensional flow fields of a turbomolecular pump(TMP) in both molecular and transition flow regions. The pumping characteristics of the TMP are investigated for a wide range of the Knudsen number. The maximum of compression ratio and of pumping speed strongly depend on the Knudsen number in transition region, while they weakly depend on the Knudsen number in free molecular flow region. The present numerical results show good agreement with the previously known experimental data. Finally. the results of the single blade row in both molecular and transition regions are used to predict the overall performance of a TMP, which has three kinds of blade with 24-rows.

  • PDF

Observation of Transition Boundary between Cold, Dense and Hot, Tenuous Plasmas in the Near-Earth Magnetotail

  • Kim, Hee-Eun;Lee, Ensang
    • Journal of Astronomy and Space Sciences
    • /
    • 제37권2호
    • /
    • pp.95-104
    • /
    • 2020
  • Properties of plasmas that constitute the plasma sheet in the near-Earth magnetotail vary according to the solar wind conditions and location in the tail. In this case study, we present multi-spacecraft observations by Cluster that show a transition of plasma sheet from cold, dense to hot, tenuous state. The transition was associated with the passage of a spatial boundary that separates the plasma sheet into two regions with cold, dense and hot, tenuous plasmas. Ion phase space distributions show that the cold, dense ions have a Kappa distribution while the hot, tenuous ions have a Maxwellian distribution, implying that they have different origins or are produced by different thermalization processes. The transition boundary separated the plasma sheet in the dawn-dusk direction, and slowly moved toward the dawn flank. The hot, tenuous plasmas filled the central region while the cold, dense plasmas filled the outer region. The hot, tenuous plasmas were moving toward the Earth, pushing the cold, dense plasmas toward the flank. Different types of dynamical processes can be generated in each region, which can affect the development of geomagnetic activities.

소형 펀치 시험에 의한 강용접부의 파괴강도 평가에 관한 연구 1

  • 유대영;정세희;임재규
    • Journal of Welding and Joining
    • /
    • 제7권3호
    • /
    • pp.28-35
    • /
    • 1989
  • It was reported that the toughness for welded region was influenced by various factors such as the gradient for prior austenite grain size, the variation of microhardness and the characteristic microstructure depending on distance from the fusion boundary. Therefore, in order to evaluate the fracture strength of the weldment in which the microstructures change continuously, it is important to assess the peculiar strength of each microstructure in welded region. It was known that the small punch(SP) test technique which was originally developed to study the irradiation damage effect for the structures of nuclear power plant was also useful to investigate the strength evaluating of nonhomogeneous materials. In this paper, by means of a small punch test technique the possibility of evaluating strength of parent and welded region in SS41 and SM53B steels was investigated. The obtained results are summerized as follows: 1) The small punch test which showed markedly the ductile-brittle transition behavior in this experiment may be applied to evaluation for the fracture strength of welded region. 2) It was shown that the ductile-brittle regime lied in Region III(plastic membrane stretching region) of the flow characteristics observed in SP test. 3) The SP test technique which shows a more precipitous energy change transition behavior than the other test technique is able to estimate the more precise transition temperature. 4) It could be seen that in comparision with the structure of parent the structure of weld HAZ in SS41 steel was improved while it in SM53B steel was deteriorated.

  • PDF