• Journal of Korean Society of Steel Construction
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• v.22 no.4
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• pp.305-312
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• 2010

The objective of this paper is to examine the structural performance of steel moment-resisting frames on the various connection details of Seismic Wide-flanged Beam-to-Rectangular Steel Tube Column connections. Although compared to an H-shaped steel tube, a rectangular steel tube has many advantages and is more efficient, its application is limited due to the lack of experience in using it and the connection details. Existing steel moment connections using the rectangular steel tube are mainly used through plate diaphragms. The processing of construction of the rectangular steel tube is so complicated that it is hard to apply it in the field. In this study, the structural performance and the earthquake capacity of the connection details that do not cut the rectangular steel tube column were investigated. A comparative analysis of the strength, rigidity, and energy absorption capacity of the welded connection details using an end-plate and a haunch was also performed.

• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.7-11
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• 2005

A single slab in which one Ni(001) atom layer embedded between two of four Rh layers is considered to examine the oscillation of magnetic moment in each layer. The all electron total-energy full-potential linearized augmented plane wave(FLAPW) method was used to calculate the spin densities, magnetic moments, density of states(DOS), and the number of electrons within each muffin-tin(MT) sphere. The magnetic moment of the center layer Ni(C) in the system of 4Rh/Ni/4Rh is calculated to be 0.34${\mu}_B$, which is 40% have magnetic moment at the interface layers by strong band hybridization with Ni(C) when Ni(001) monolayers is inserted, and the magnetic moment shows a damped oscillation as we go from center Ni(C) layer to the surface Rh(S). From the calculated density of states, it is found that the Fermi level shifts inside the energy band of the Ni(C) in affection of Rh(001).

• Journal of the Korean Magnetics Society
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• v.14 no.3
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• pp.94-98
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• 2004

The electronic structures and magnetism of MgCCo$_3$(001) surface terminated by the plane with the MgCo-Term (Mg, Co terminated) and the CCo-Term (C, Co terminated) were investigated using the all-electron full-potential linearized augmented Plane-wave method. For the MgCo-Term, the magnetic moment of Co atom of the surface is strongly enhanced to 1.00$\mu$$_{B}$, while the magnetic moment of Co atom of the subsurface is similar to that of the center layers. For the CCo-Term, the magnetic moments of Co atoms are enhanced to 0.75 and 0.80$\mu$$_{B}$ for the surface and subsurface layers, respectively. The magnetic moments of C and Mg atoms are coupled antiferromagnetically to that of the neighbour Co atoms. From the calculated density of states, we see that the enhancements of magnetic moments of Co atoms are closely related to localization of the Co-3d states.

• Korean Journal of Optics and Photonics
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• v.2 no.4
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• pp.203-208
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• 1991

We investigated the nonradiative energy transfer process from Rhodamine 6G to Malachite Green in ethylen glycol solvent using time correlated single photon counting system equipped with a modelocked Ar ' laser. The reduced concentration and critical transfer distance for various acceptor concentration were obtained by using a full-fitting analysis of the fluorescence decay curves. We found that Huber model is more suitable than Forster model and the influence of energy migration through the dipole-dipole interaction becomes more significant for the low acceptor concentrations relative to the donor concentration($5\times 10^4$mol/l).

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.388-392
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• 2007

지구온단화와 이상기후에 의해 시설물 피해가 나날이 증가하고 있으며, 농촌의 인구감소 및 고령화에 의해 이러한 집중강우등에 대한 대처도 어려운 실정이다. 현재 전국에서 농업용수 공급을 위해 사용하고 있는 농업용 저수지는 17,882개소로서 이 중 축조한지가 35년 이상 경과된 저수지가 15,856개소로서 88.7%나 차지하고 있다. 이러한 현상은 저수지를 구성하고 있는 각종 부대시설의 노후화로 귀결되며 농업용수의 낭비 및 효율적인 운영을 위해서는 시설의 현대화가 필수적이라고 할 수 있다. 따라서 본 연구에서는 저수지에서 물을 직접 공급하는 시설인 사통수문을 대상으로 현대화를 이룩하고 또한 사용동력도 대체에너지를 이용하기 위한 방안을 제시하였다. 사통수문의 수문비는 수중의 압력을 효율적으로 분산시킬 수 있는 원형수문비와 수중에서도 사용동력을 가장 적게 할 수 있는 밸브형을 기준으로 개발을 하였으며, 수문비와 구동부를 연결하는 작동 롯드의 힘전달을 최소화하기 위하여 유니버셜 쪼인트를 볼밸브형으로 개발하였다. 이에 따라서 작동용 롯드의 길이가 길어져도 수문비에 걸리는 작동모멘트를 최소화하여 태양광을 이용한 동력사용이 가능해졌다. 특히 수중에서 움직이는 특성을 감안하여 원형 수문비의 경우에는 수문비와 수문틀 사이에 마찰력을 감소시키기 위하여 수문틀측을 약간 경사지게 가공을 하고 중간에 볼 베이렁을 부착시켜 수문개폐가 원활토록 지수부의 구조변화를 하였다. 또한 농업용수공급시 수류와 함께 유입되는 저수지 내 오물을 차단하기 위하여 수문의 전면에 스크린을 설치하였으며 토사퇴적으로 인하여 수문작동의 방해가 되지 않도록 하기 위하여 토목구조물을 설치하였다. 그리고 동력전달을 효율적으로 하기 위하여 Solar Unit으로부터 나오는 전기를 중전기에서 밧데리로 축전을 시키고 완전 충전 후에는 나머지 전기는 방전이 되도록 회로를 구성하였다. 사통수문 자원조사 결과에 의하면 현재 저수지에 물공급을 하는 수문은 취수탑 형식이 70% 이상을 차지하고 있으며 나머지 30%의 사통수문 중 원형수문비가 98% 이상을 차지하고 있다. 현재 대체에너지를 사용하는 저수지 사통수문은 없는 것으로 조사되었으며 전력을 사용하는 사통도 조사결과에 의하면 20% 이내로 나타났다. 이러한 결과는 향후 수리시설 개보수시 적은 예산으로 사업을 시행하는 경우 사통수문의 설치방향의 지표가 될 것으로 판단되며 수리시설의 운영관리에 대한 새로운 대안으로 제시할 수 있다.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.257-260
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• 2005

We investigated the half-metallicity and magnetism for the zinc-blende CrS(001) surfaces by use of the full-potential linearized augmented plane wave (FLAPW) method. We considered two-types of (001) surfaces terminated by Cr (Cr-Term) and S (S-Term) atoms, respectively. From the calculated layer-by-layer density of states, it is found that both of the systems retain the half-metallicity at the (001) surfaces. The calculated magnetic moment ($4.07\;{\mu}_B$) for the CrS(S) atom in Cr-Term is enhanced considerably compared to the bulk value ($3.61\;{\mu}_B$) while that ($3.15\;{\mu}_B$) of the Cr(S-1) in S-Term is much reduced.

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.423-434
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• 2017

In this paper a systematic numerical analysis is performed to obtain the hysteresis behavior of partially restrained top and seat angle connections subjected to cyclic loading. This connection includes superelastic shape memory alloy (SMA) angles and rods in order to secure the recentering capacities as well as proper energy dissipation effects of a CFT composite frame. The three-dimensional nonlinear finite element models are constructed to investigate the rotational stiffness, bending moment capacity and failure modes. A wide scope of additional structural behaviors explain the different influences of the connection's parameters, such as the various thickness of connection angles and the gage distance of steel and SMA rods.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.61-64
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• 2008

A combination of CFT column and RC flat plate without formworks is very effectively rapid constructions. This paper verified the lateral resisting capacity of CFT column-RC flat plate exterior connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to moment-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT-E2 specimen a critical section was extended and maximum moment increased 20% respectively in comparison to general RC column specimen. In BME and CFT-E1 specimens generally shear governed behaviors and CFT-E2 specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.147-156
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• 2012

In recent years, many high-rise buildings have been constructed in irregular structural system with inclined columns, which may have effect on the structural behavior of beam-column joints. Since the external load leads to shear and flexural forces on the inclined columns in different way from those on the conventional vertical columns, failure mode, resistant strength, and ductility capacity of the inclined column-beam joints may be different than those of the perpendicular beam-column joints. In this study, six RC inclined beam-column joint specimens were tested. The main parameter of the specimens was the angle between axes of the column and beam (90, 67.5, and 45 degree). Test results indicated that the structural behavior of conventional perpendicular beam-column joint was different to that of the inclined beam-column joints, due to different loading conditions between inclined and perpendicular beam-column joints. Both upper and lower columns of perpendicular beam-column joints were subjected to compressive force, while the upper and lower columns of the inclined beam-column joints were subjected to tensile and compressive forces, respectively.

• Journal of the Korean Magnetics Society
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• v.16 no.3
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• pp.178-181
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• 2006

We have investigated the Mn concentration-dependent structural, optical, magnetic properties in IV-VI diluted magnetic semiconductor $Si_{1-x}Mn_xTe_{1.5} $ crystals prepared by the vertical Bridgman technique. X-ray studies showed the single crystalline hexagonal crystal structure. From the optical absorption measurements energy band gap were found to decreases with increasing x and temperature. From the magnetization measurements the samples had ferromagnetic ordering with Curie temperature $T_C$ about 80 K. With increasing Mn concentration, the average magnetic moments per Mn atom determined from the saturated magnetization increased.