• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.269-272
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• 2002

Turbidity currents, often develop after heavy storm events, deliver various non-point pollutants and tend to lead eutrophication, depressed dissolved oxygen, and sedimentation in reservoirs. Field observations were performed to investigate the flow regimes of turbidity currents and their impact on reservoir water quality in Daecheong Reservoir. A 2D laterally-averaged hydrodynamic and water quality model was applied to simulate the temporal and spatial distributions of turbidity in the reservoir, and evaluated by comparing with the field data.

• 콘크리트학회논문집
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• 제12권6호
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• pp.57-66
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• 2000

The truss analogy for the analysis of beam-columns subjected of shear and flexure is limited by the contribution of transverse and longitudinal steel and diagonal concrete compression struts. However, it should be noted that even though the behavior of reinforced concrete beam-columns after cracking can be modeled with the truss analogy, they are not perfect trusses but still structural elements with a measure of continuity provided by a diagonal tension field. The mere notion of compression field denotes that there should be some tension field coexisting perpendicularly to it. The compression field is assumed to form parallel to the crack plane that forms under combined flexure and shear. Therefore, the concrete tension field may be defined as a mechanism existing across the crack and resisting crack opening. In this paper, the effect of concrete tensile properties on the shear strength and stiffness of reinforced concrete beam-columns is discussed using the Gauss two-point truss model. The theoretical predictions are validated against the experimental observations. Although the agreement is not perfect, the comparison shows the correct trend in degradation as the inelasticity increases.

• 천문학회보
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• 제41권1호
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• pp.51.1-51.1
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• 2016

Turbulent motions produce density and magnetic field fluctuations. Correlation between density and magnetic field fluctuations are important for interpretation of observations, such as the rotation measure (RM) and dispersion measure (DM). We study the several factors that can affect the correlation between two. In particular, we numerically investigate how the correlation time of driving affects the correlation between density and magnetic field. We perform compressible MHD turbulence simulations at different sonic Mach number and consider two different driving schemes - continuously changing driving and delta-correlated driving. The continuously changing driving results in strong anti-correlation between density and magnetic field when sonic and Alfvenic Mach numbers are similar unity. The delta-correlated driving produces virtually no correlation between two fields.

• 천문학회보
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• 제43권2호
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• pp.45.2-45.2
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• 2018

Twisted magnetic flux tubes (also called magnetic flux ropes) are believed to play a crucial role in solar eruptive phenomena. The evolution of a single flux rope with or without the influence of an overlying field of a simple geometry has been extensively studied and its physics is rather well understood. Observations show that interacting flux tubes are often involved in solar eruptions. It was Lau and Finn (1996) who intensively studied the interaction between two flux ropes, whose footpoints are anchored in two parallel planes. In this too simplified setting, the curvature of the flux rope axial fields is totally ignored. In our study, the footpoints of flux ropes are placed in a single plane containing a polarity inversion line as in the real solar active region. Our simulation study is performed for four cases: (1) co-axial field and co-axial current (co-helicity), (2) counter-axial field and co-axial current (counter-helicity), (3) co-axial field and counter-axial current (counter-helicity), and (4) counter-axial field and counter-axial current (co-helicity). Except case 3, each case is found to be related with certain eruptive features.

• Current Optics and Photonics
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• 제6권2호
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• pp.191-195
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• 2022

We investigate the lateral far-field pattern characteristics, including divergence angle change and far-field pattern analysis as output power increases, of narrow-emitter-width 850 nm GaAs/AlGaAs laser diodes (LDs). Each LD has a cavity of 1200 and 1500 ㎛ and narrow emitter width of 2.4 ㎛ for the top and 4.6 ㎛ for the bottom. The threshold currents are 35 and 40 mA, and L-I kinks appear at power levels of 326 and 403 mW, respectively. The divergence angle tends to increase due to the occurrence of first-order lateral mode and the thermal lensing effect. But with the L-I kink, the divergence angle decreases and the far-field pattern becomes asymmetric. This is due to coherent superposition between the fundamental and the first-order lateral mode. We provide detailed explanations for these observations based on high-power laser diode simulation results.

• 대한수의사회지
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• 제9권3호
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• pp.3-12
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• 1965

From the clinical observations and surgical interferences made on the fifteen cases surgical gastric disease of dairy cows in the field, the following conclusion regarding to the traumatic reticulitis, omasal impaction and abomasal displacement may made .

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.158-158
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• 2006

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.922-923
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• 2005

• 천문학회보
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• 제29권2호
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• pp.37.1-37.1
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• 2004

• 천문학회보
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• 제45권1호
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• pp.29.1-29.1
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• 2020

I review the status of the concordance (standard) LCDM model of cosmology in light of current observations discussing about the apparent tensions in estimation of the key cosmological parameters. I will also briefly discuss the future of the field at the era of the next generation of the astronomical/cosmological surveys.