Beam bracing is applied to prevent the relative displacement of the top and bottom flanges or to effectively control the twisting of the section, and the lateral stability of the beams are provided by lateral bracing, torsional bracing or a combination of both. Modular steel I-girders are laterally interconnected by torsional bracings that are installed to increase the resistance to lateral torsional buckling. In this paper, numerical parametric study was carried out by varying the crossbeam web height to examine the effects of the web torsional stiffness. Three-dimensional finite-element analysis using the commercial finite element software ABAQUS was obtained for the parametric numerical analyses of a series of feasible two-girder models, and the failure mode, lateral-torsional buckling strength and the moment-displacement behavior of the main girders was determined.

Microstructural analysis of a (α+β) Ti alloy was investigated to consider phase transformation in each step of thethermo-mechanical process using by SEM and TEM EDS. The TAF (Ti-6Al-4Fe) alloy was thermo-mechanically treated withsolid solution at 880oC, rolling at 880oC and annealing at 800oC. In the STQ state, the TAF microstructure was composedof a normal hcp α and metastable β phase. In a rolled state, it was composed of fine B2 precipitates in an α phase, whichhad high Fe segregation and a coherent relationship with the β matrix. Finally, in the annealing state, the fine B2 precipitateshad disappeared in the α phase and had gone to the boundary of the α and β phase. On the other hand, in a lower rollingtemperature of 704oC, the B2 precipitates were more coarse in both the α and the boundary of α and β phase. We concludedthat microstructural change affects the mechanical properties of formability including rolling defects and cracks.

Metastable phase characteristics of beta Ti alloys were investigated to consider the relationship of the microstructureand diffraction pattern in TEM. TEM analysis showed that the microstructure was mottled as a modulated structure, and thediffraction pattern was composed of spot streaks between the main spots of a stable beta phase with a specific latticerelationship. The modulated structure may be induced by short distance slip or atom movement during a very short intervalof solution treated and quenched (STQ) materials. The athermal ω phase, which could be precipitated at low temperature aging,is also analysed by the metastable phase. The metastable phases including athermal ω phase had a common characteristic ofhardened and brittle behavior because the dislocation slip was restricted by a super lattice effect due to short distance atommovement at the metastable state.

This study presented the analytical safety evaluation of precast modular bridge super-structure, using standardized modular members and robotic construction during the transportation routing and lifting conditions. In order to evaluate the safety performance of the bridge system, linear and nonlinear 3D full scale Finite Element (FE) for 12 m and 16 m standardized modular blocks was developed in ABAQUS and then analytical study was classified into two different structural systems according to steel girder structures: 1) modular bridge block lifting method including the steel girder system; 2) modular bridge block lifting method without the steel girder system. As a result, in analytical study, the results revealed that the maximum stress of each modular member was in maximum allowable stresses, during lifting condition. However, the stress concentration at the connected area was more critical in comparison to the behavior of entire modular blocks both 12 m and 16m, during lifting time.

본 연구에서는 두 나라에 걸쳐 경영활동이 전개되는 경우 기업에서의 다양한 문화적 배경이 동일한 조직성과에 대한 귀인양식(attribution pattern)에 어떤 체계적인 차이를 보이는지를 알아보고자 하였다. 이를 위해 한국의 반도체 제조 기업에 근무하는 미국인과 한국인 근로자를 대상으로 이들이 자기 회사의 성과를 어떻게 귀인 시키는지를 살펴보았다. 연구 결과, 미국인 근로자는 기업 실적의 책임에 있어서 시장 요인을 더 중요하게 인식한 반면, 한국인 근로자는 오히려 정부 요인을 기업 실적의 중요한 원인으로 인식하고 있었다. 그리고 한국인 근로자가 미국인 근로자보다 회사의 저조한 실적에 대해 더 많은 개인적 책임감을 인식하는 경향을 발견하였으나 연구방법론에 따라 통계적 유의성에 대한 해석에 차이를 보였다. 또한 집단기여에 대한 추가 분석을 실시한 결과 한국인 근로자와 미국인 근로자가 회사의 저조한 실적을 회사 자체의 책임으로 보는 정도에는 차이가 나타나지 않았다. 마지막으로 본 연구 결과의 시사점과 한계, 후속 연구가 논의 되었다.

뇌기능 장애 환자에서 자세균형 제어능력의 저하는 보행 및 일상생활동작 수행 등에 어려움을 초래하며 이에 대한 정확한 평가 및 치료를 위하여 일상의 환경변화와 유사한 상황을 제공하고 이에 따른 자세균형 조절 능력을 파악하는 것이 중요하다. 본 연구는 뇌기능 장애 환자에서 가상적 움직이는 환경에 따른 자세균형 조절 기능을 정확히 평가하고 환경의 움직임이 자세균형 조절에 미치는 영향을 분석하였다. 15명의 뇌기능 장애 환자들과 정상인 15명을 대상으로 실생활과 유사한 환경의 조성을 위하여 HMD를 이용한 가상 환경 움직임(Virtual Moving Surround)을 네 가지 다른 패턴으로 제공하였다. 자세동요의 정도는 힘판을 이용하여 신체압력중심의 변화를 전체이동거리, 동요주파수, 최대 빈도 COP 위치로 측정하였으며 가상 환경의 차이에 따른 변화를 비교 분석하였다. 연구결과 검사 재검사 신뢰도평가에서 일관된 분석결과를 나타냈고 뇌 기능장애 환자와 정상인의 분석에서는 두 그룹간의 차이를 확인할 수 있었다. 특히 전후로 빠르게 변하는 가상 환경에서 가장 큰 자세동요를 나타내었고 통계적으로 유의한 차이가 있었다. 본 연구를 통해 뇌기능 장애 환자에서 가상 환경 변화가 자세균형 조절에 미치는 영향을 확인할 수 있었으며 이러한 환자들을 위한 치료와 평가 환경 조성 등에도 유용한 자료로 쓰일 수 있을 것으로 사료된다

The walls of guard cells have many specialized features. Guard cells are present in the leaves of bryophytes, ferns, and almost all vascular plants. However, they exhibit considerable morphological diversities. There are two types of guard cells: the first type is found in a few monocots, such as palms and corn, and the other is found in most dicots, many monocots, mosses, ferns, and gymnosperms. In corns, guard cells have a characteristic dumbbell shape with bulbous ends. Most dicot and monocot species have kidney-shaped guard cells that have an elliptical contour with a pore at its center. Although subsidiary cells are common in species with kidney-shaped stomata, they are almost always absent in most of the other plants. In this study, there were many different stomatal features that were associated with kidney-shaped guard cells, but not dumbbell shaped guard cells, which are present in most grasses, such as cereals. Each plant investigated exhibited different characteristic features and most of these plants had kidney-shaped guard cells. However, the guard cells of Chamaesyce supina Mold, were often more rectangular than kidney-shaped. In contrast, Sedum sarmentosum guard cells were of the sink ensiform type and in Trifolium repens, the guard cells exhibited a more rhombic shape. Therefore, kidney-shaped guard cells could be divided into a number of subtypes that need to be investigated further.

This study presents the Finite Element(FE) analysis using ABAQUS with respect to new type of modular bridges. In addition, this research was carried out for safety analysis in term of stresses and deformation of the modular bredge incorporated with GFRP to the steel plate during lifting.

To determine the type and dimension of modular deck, the parameter study was executed. Decks of three types were proposed and static tests were performed to verify the structural performance. From the test results, the full steel plate composite deck had about three times strength as the others.

To determine the type and dimension of modular deck, the parameter study was executed. Decks of three types were proposed and static tests were performed to verify the structural performance. From the test results, the full steel plate composite deck had about three times strength as the others.

배관 내부의 방사성 오염도를 측정하기 위한 ZnS(Ag)/플라스틱섬광체 조합의 알파/베타선 동시측정용 phoswich 검출기를 개발하였다. 알파/베타선 동시측정용 phoswich 검출기의 오염위치에 따른 검출 성능을 PSD (Pulse shape discrimination) 방법을 이용하여 평가하였다. 또한, 검출기를 방사성 오염물질로부터 보호하기 위한 오염방지용 필름에 대한 방사선 감쇄 정도를 실험적으로 평가하였다. PSD 방법으로 알파/베타선 분리 정도를 측정한 결과 충분히 알파와 베타선이 분리되었으며 오염방지용 필름의 적용 가능성을 확인하였다.