• Nuclear Engineering and Technology
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• 제33권6호
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• pp.605-618
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• 2001

For the mechanical stability assessment of a deep underground high-level waste repository. computer simulations using FLAC3D were carried out and important parameters including stress ratio, depth, tunnel size, joint spacing, and joint properties were chosen from sensitivity analysis. The main effect as well as the interaction effect between the important parameters could be investigated effectively using fractional factorial design . In order to analyze the stability of the disposal tunnel and deposition hole in a discontinuous rock mass, different modelings were performed under different conditions using 3DEC and the influence of joint distribution and properties, rock properties and stress ratio could be determined. From the three dimensional modelings, it was concluded that the conceptual repository design was mechanically stable even in a discontinuous rock mass.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.784-786
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• 2009

Thermal transfer of emitting layer from the donor film to the substrates depends on the physical interaction between the donor film, the emitting layer, and the hole-transport layer (HTL). The interfacial adhesion between the donor film and the EML, the cohesive force of the EML, and the interfacial adhesion between the EML and the HIL have to be optimized to achieve good LITI pattern quality. It was found that surface pretreatment of the donor plate was important on the laser induced thermal transfer of the emitting layer onto the HIL layer of the OLED devices.

• Steel and Composite Structures
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• 제20권1호
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• pp.71-89
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• 2016

In steel and concrete composite girders, the load transfer between the steel beam and the concrete slab is commonly ensured by installing shear connectors. In this paper, to investigate the nonlinear behavior of perfobond connectors, a total of 60 push-out specimens were fabricated and tested with the variables for the hole diameter, the concrete strength, the thickness of concrete slab, the diameter, strength and existence of perforating rebar, the thickness, height and distance of perfobond ribs. The failure mode and the load-slip behavior of perfobond connectors were obtained. A theoretical model was put forward to express the load-slip relationship. Analytical formulas of shear capacity and peak slip were also proposed considering the interaction between the concrete dowel and the perforating rebar. The calculation results of the proposals agreed well with the experimental values.

• 천문학회보
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• 제36권1호
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• pp.50.2-50.2
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• 2011

It is believed that active galactic nuclei (AGN) is powered by super massive black hole (SMBH). But how the AGN activity is triggered is still unclear. Some studies suggest that gas inflow by merging can trigger AGN activity. However, it is difficult to find observational evidence because merging features such as tidal tail, shell are faint. Using images taken at Maidanak 1.5m telescope and CFHT, we investigated whether merging features are seen commonly on AGN host galaxies. We found that 3 to 4 of the currently studied 6 AGN show features disturbed by gravitational interaction. This result implies that AGN activity may correlates with merging. We plan to expand the sample size in the near future.

• Journal of Photoscience
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• 제6권3호
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• pp.153-156
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• 1999

We have introduced the nonresonant holes in the satellite hole spectrum to examine the interaction of two tautomers of thionin to various polynucleotides, including [d(GC)7]2 , [d(AT)7]2 and calf thymus. The saturated depths of nonresonant holes are much reduced upon interacting with [d(GC)7]2 and calf thymus than with [d(AT)7]2 , implying that the binding affinity of thionin to [d(GC)7]2 and calf thymus is stronger than [d(AT)7]2 . In addition, the less perturbation on the exocyclic amino group of the amino -form of thionin upon interacting with [d(AT)7]2 suggests that a direct hydrogen bond formed between the amino group of thionin and the phosphate of nucleic acids is unlikely.

• Bulletin of the Korean Chemical Society
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• 제6권3호
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• pp.168-170
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• 1985

The pairing properties of electronic structure are investigated from ab initioists' point of view. Numerical results of exact ab initio effective valence shell Hamiltonian are compared with simple semiempirical Hamiltonian calculations. In the oxygen atom case it was found that effective three-electron interaction terms break the similarity between electron-states and hole-states. With the trans-butadiene as an example the pairing theorem was studied. Even for alternant hydrocarbons, the deviation from the pairing was found to be enormous. The pairing theorem, which is usually stated for semiempirical Hamiltonians, is not valid when the exact effective Hamiltonian is considered. The present study indicates that comparisons between the pairing theorem of semiempirical methods and ab initio effective Hamiltonian give important information on the accuracy of semiempirical methods.

• 대한기계학회논문집B
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• 제24권2호
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• pp.288-297
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• 2000

This paper describes the results of an experimental investigation of the flow characteristics and the heat transfer rate on a surface by interaction of a pair of vortices. The test facility consists of a boundary-layer wind tunnel with a vortex introduced into the flow by half-delta wings(vortex generators) protruding from the surface. In order to control the strength of the two longitudinal vortices, the angles of attack of the vortex generators are varied from 20 degree to 45 degree, but spacings between the vortex generators are fixed to 4 cm. The 3-dimensional mean velocity downstream of the vortex generators is measured by a five-hole pressure probe, and the hue-capturing method using the thermochromatic liquid crystals has been used to provide the local distribution of the heat transfer coefficient. By using the method mentioned above, the following conclusions are obtained from the present experiment. The boundary layer is thinned in the regions where the secondary flow is directed toward the wall and thickened where it is directed away from the wall. The peak augmentation of the local heat transfer coefficient occurs in the downwash region near the point of minimum boundary-layer thickness. Streamwise distributions of averaged Stanton number on the measurement planes show very similar trends for all the cases(${\beta}=20^{circ},\;30^{\circ}\;and\;45^{\circ}$).

• 대한기계학회논문집B
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• 제24권2호
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• pp.298-305
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• 2000

The flow characteristics and the heat transfer rate on a surface by interaction of a pair of vortices were studied experimentally. The test facility consisted of a boundary-layer wind tunnel with a vortex introduced into the flow by half-delta wings protruding from the surface. In order to control the strength of the longitudinal vortices, the angles of attack of the vortex generators were varied from - 20 degree to - 45 degree, but spacings between the vortex generators were fixed to 4 cm. The 3-dimensional mean velocity measurements were made using a five-hole pressure probe. Heat transfer measurements were made using the thermochromatic liquid to provide the local distribution of the heat transfer coefficient. Unlike common flow down, common flow up vortices moved toward the centerline as they developed and interacted strongly with each other but not with the boundary layer. Spanwise profiles of Stanton number were similar for ${\beta}=-20^{\circ}\;and\;-35^{\circ}$, but not similar for ${\beta}=-45^{\circ}$. The case of ${\beta}=-20^{\circ}\;and\;-35^{\circ}$ showed the two peak Stanton number, but the case of ${\beta}=-45^{\circ}$ showed the only one peak Stanton number.

• 대한기계학회논문집B
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• 제27권11호
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• pp.1618-1629
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• 2003

The effects of the interaction between flow field and heat transfer caused by the longitudinal vortices are experimentally investigated using a five hole probe and a transient liquid crystal technique. The test facility consists of a wind tunnel with vortex generators protruding from a bottom surface and a mesh heater. In order to control the strength of the longitudinal vortices, the angle of attack of vortex generators used in the present experiment is 20$^{\circ}$, and the spacing between the vortex generators is 25mm. The height and cord length of the vortex generator is 20mm and 50mm, respectively. Three-component mean velocity measurements are made using a f-hole probe system, and the surface temperature distribution is measured by the hue capturing method using a transient liquid crystal technique. The transient liquid crystal technique in measuring heat transfer has become one of the most effective ways in determining the full surface distributions of heat transfer coefficients. The key point of this technique is to convert the inlet flow temperature into an exponential temperature profile using the mesh heater set up in the wind tunnel. The conclusions obtained in the present experiment are as follows: The two maximum heat transfer values exist over the whole domain, and as the longitudinal vortices move to the farther downstream region, these peak values show the decreasing trends. These trends are also observed in the experimental results of other researchers to have used the uniform heat flux method.

• 대한기계학회논문집
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• 제12권3호
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• pp.551-560
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• 1988

본 연구에서는 해석하려는 시스템의 유동 및 열전달 현상의 개념도를 Fig.1 에 나타내었다. 고체 입자는 윗부분 홈으로부터 분사되어, 선택적 투과면을 통해서 입사되는 복사열을 흡수 하며, 기체는 아래 또는 위의 홈 부분으로부터 들어와서 고체 입자와의 대류열전달로 가열이 된다. 기차게 아래 홈에서부터 분사되는 경우 대류에 의해 가열된 기체가 역성층화로 인해 부력을 받게 되어, 고체 입자의 하강 속도가 감 소할 때 입자의 체류 시간의 증가에 따른 복사열의 흡수효과에 대하여 고찰하였으며 입자의 크기, 투사 복사량, 분사속도, 입자의 질량유량 등을 파라미터로 하여 이들의 변화에 따른 영향을 규명하였다. 2-방연계를 고려한 2-방정식 모델을 구성하고 고체 입자에 대하여는 Lagrangian 방법으로 기술하였으며 수치해석에 있어 유한차분법을 도 입하고 두 상간의 상호연계는 PSI-Cell 방법을 이용하였고 복사 열유속은 2-유속 모델 (two-flux model)을 도입하여 계산하였다.