• Applied Biological Chemistry
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• v.45 no.4
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• pp.223-227
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• 2002

Characteristic stereostructures of farnesyl protein transferase (FPTase) inhibition materials isolated from Artemisia sylvatica and regioselectivity of biogenic Diels-Alder reactions between dehydromatricarin molecules A and B were examined quantitatively. Results revealed that the major reaction of frontier molecular orbital (FMO) interaction proceeds through charge-control reaction between LUMO of A16, dienophile and HOMO of B1, diene, and the isolated 8-acetylarteminolide and artanomaloide were minor products. FPTase inhibition activity and hydrophobicity of 8-acetylarteminolide were $pI_{50}=3.75$ and logP=2.62, respectively. FPTase inhibition activity of 8-acetylarteminolide was higher than those of artanomaloide and dehydromatricarin.

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.543-548
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• 1988

The metal-support interaction was studied in 1∼5wt% copper supported on $\gamma-alumina$ and titania systems by temperature programmed reduction (TPR) and EPR. When the samples were treated with oxygen at $500^{\circ}C$, the relative area of H2-TPR peak at higher temperature increased with copper content for titania system whereas that of lower temperature increased for ${\gamma}$-alumina system. After oxygen treatment at $500^{\circ}C,\;{\gamma}$-alumina system showed a TPR peak at $300^{\circ}C$ while two peaks at 120 and $180^{\circ}C$ were found in titania system. A typical $Cu^{2+}$ EPR signal was observed on ${\gamma}$-alumina but very broad and small one on titania. From the results, it was suggested that the metal-support interaction increases in the order of silica < titania < ${\gamma}$-alumina and copper oxide has different loading characteristics depending on the supports.

• Journal of the Korean GEO-environmental Society
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• v.2 no.4
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• pp.15-27
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• 2001

This paper proposes the force equations(thrust, moment) of corrugated steel culverts through the finite element method. The conditions for maximum thrust and maximum moment are determined from the analysis of soil-structure interaction during the three construction stages, such as backfill to the crown, backfill to the soil cover, and live loads. The proposed form of thrust and moment equations are deduced from the analysis of behaviour and the application of Castigliano's second theorem for the semi-arch structure. Finally, the coefficients used in the proposed equations are determined from a large number of analysis for the various geometries and the soil-structure relative stiffness under the conditions of maximum thrust and maximum moment.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.20-25
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• 2005

The authors performed the underwater explosion analysis for the liquified oxygen tank - a kind of fuel tank of a mid-size submarine, and tried to verify the structural safety for this structure. First, the authors reviewed the theory and application of underwater explosion analysis, using a Structure-Fluid Interaction technique and its finite element modeling scheme. Next, the authors modeled the explosive and sea water as fluid elements, the LOX tank as structural elements, and the interface between the two regions as the ALE scheme. The effect on shock pressure and impulse of fluid mesh size and shape are also investigated. Upon analysis, it was found that the shock pressure due to explosion propagated into the water region, and hit the structure region. The plastic deformation and the equivalent stress were apparent at the web frame and the shock mount of LOX structure, but these values were acceptable for the design criteria.

• Journal of Ocean Engineering and Technology
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• v.27 no.5
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• pp.51-62
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• 2013

The water wave interactions on any three-dimensional structure of arbitrary geometry can be calculated numerically through the use of source distribution or Green's function techniques. However, such a method can be computationally expensive. In the present study, the water wave interactions in floating circular cylinder arrays were investigated numerically using the eigenfunction expansion method with the three- dimensional potential theory to reduce the computational expense. The wave excitation force, added mass coefficient, radiation damping coefficient, and wave run-up are presented with the water wave interactions in an array of 5 or 9 cylinders. The effects of the number of cylinders and the spacing between them are examined because the water wave interactions in floating circular cylinder arrays are significantly dependent upon these.

• Asia Marketing Journal
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• v.3 no.2
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• pp.69-91
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• 2001

고객이 서비스상의 실패에 대해 때로는 강한 부정적 반응을 보이기에 서비스를 제공하는 조직의 서비스회복능력은 고객만족을 달성하기 위해 강력하고 효율적으로 운영되어야 한다. 따라서 본 연구는 온라인상의 서비스인 ISP업체(10개의 회사)를 대상으로 온라인 서비스 상에서 고객이 서비스상의 불만을 경험할 때 기업이 고객의 불만을 회복시켜 만족으로 전환시키려는 회복속성들이 실제로 고객이 가지는 분배상의 공정성, 절차상의 공정성 및 상호작용 공정성에 어떤 영향을 미치는가를 실증적으로 검증하기 위한 것이다. 이를 위해 10개의 ISP업체를 선정하고 해당 업체에 대해 불만을 가진 고객들이 기업의 불만제거 노력에 대해 평가하도록 하였다. 가설 검증을 위해 LISREL을 이용하여 서비스의 회복속성인 보상, 신속한 반응, 무반응, 사과, 사전보상제공 등이 분배상공정성, 절차상 공정성, 상호작용 공정성에 직접적으로 미치는 효과를 파악하고 이 공정성의 요인들이 만족에 미치는 영향도 실증적으로 검증하였다. 온라인 상이라는 새로운 환경을 고려하여 기존의 모델에서 간과된 부분을 확인하기 위해 확장 모델을 제시하여 새로운 의미를 가진 경로가 존재하는지 확인하고 이 부분에서 유의적인지 않은 경로를 배제한 수정모델을 제시하였다. 기존의 연구를 바탕으로 제시된 가설은 연구모델에서 경로 계수를 추정하고 이에 대한 t값을 통해 검증하였다. 본 연구에서 제시하는 시사점으로는 고객의 서비스 실패 및 회복상황에 대한 평가의 이론적 원칙을 설명하고 관리자에게 각각의 서비스 실패와 일치하는 서비스 회복전략을 제시하여 운영상의 가이드 라인을 제시한다고 할 수 있다

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.101-110
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• 2012

The side jet effects between jet flow and free-stream on a missile body were investigated by experimentally and numerically for modeling aerodynamic coefficients in pitch plane. K-factors for normal force and pitching moment were introduced to estimate the side jet effects. The main parameters of the jet interaction phenomena were angle of attack, jet pressure ratio, Mach number and jet bank angle. The K-factors for normal force coefficient and pitching moment coefficients in pitch plane were analysed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.774-777
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• 2010

본 논문에서는 MR 감쇠기의 비선형 특성을 등가의 선형감쇠로 치환하기 위한 방법으로 Newmark와 Hall이 제안한 감쇠계수를 이용하였다. 응답스펙트럼의 감쇠율을 나타내는 감쇠기계수는 구조물의 최대변위를 이용하여 등가감쇠비를 추출할 수 있다는 장점을 가지고 있다. 하지만 이러한 응답스펙트럼은 구조물에 작용하는 지진하중의 특성에 따라 경향이 달라진다. 본 논문에서는 기존의 등가감쇠비 산정식을 수정하여 제안하고, 지진하중 특성에 따른 등가감쇠비의 변화를 살펴보았다. MR 감쇠기의 등가감쇠비는 가진하중과 최대마찰력의 비율에 따라 결정되며, 장주기 구조물의 경우 등가감쇠비가 감소한다. MR 감쇠기의 점성은 마찰감쇠와의 상호작용에 의해 단순한 산술합 이상의 감쇠비 증가 효과를 가진다.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.267-279
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• 1990

The adsorption mechanisms of phenols on XAD-2 and XAD-7 resins were studied by using the distribution coefficient(log Kd) measured in the optimum adsorption conditions. It was observed that the Langmuir adsorption isotherm, indicating a molecular size-dependent adsorption, was appropriate for characterizing the adsorption behaviors of phenols on XAD-2 and XAD-7 resins. The adsorption energies of phenols on XAD resins were calculated by Lennard-Jones potential equation. In the calculation of the adsorption energy, the molecular radii and dipole moments of the resins and phenols were calculated by their van der Waals volumes and Debye equation, respectively. The stacking factor (F) were determined from the radio of the equilibrium distance to the stacking distance of molecules. In order to explain the adsorption energy calculated from the stacking factor it was compared with the adsorption enthalpy for each of phenols which was experimentally determined by batch adsorption shake method. It was observed that the adsorption enthalpy of phenolate ions on the XAD resins was likely to be more seriously affected by dispersion interaction than by a dipole or a charge interaction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.3
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• pp.243-254
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• 2009

Tunnel problems relate to pore water pressure generally occur due to the restriction of groundwater flow into the tunnel which is generally caused by the deterioration of drainage systems. Previous studies have identified the problem as combined mechanical and hydraulic interaction occasions. In this study, detrimental effects of pore water pressure on the lining were investigated using the finite element method considering deterioration of the drainage system. Particularly, double-lined linings with drain-holes are considered. Deterioration of drainage system is represented as blockages of drain-holes. It is identified that the secondary lining ran be influenced by the deterioration of drainage system. It is shown that a tunnel with all drain-holes blocked moved upward, and unbalanced drain-hole blocking may result in torsional behavior of the tunnel which causes significant damages to the secondary linings.