• 한국표면공학회지
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• 제49권3호
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• pp.286-300
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• 2016

Pd-Ag alloy membranes have attracted a great deal of attention for their use in hydrogen purification and separation due to their high theoretical permeability, infinite selectivity and chemical compatibility with hydro-carbon containing gas streams. For commercial application, Pd-based membranes for hydrogen purification and separation need not only a high perm-selectivity but also a stable long-term durability. However, it has been difficult to fabricate thin, dense Pd-Ag alloy membranes on a porous stainless steel metal support with surface pores free and a stable diffusion barrier for preventing metallic diffusion from the porous stainless steel support. In this study, thin Pd-Ag alloy membranes were prepared by advanced Pd/Ag/Pd/Ag/Pd multi-layer sputter deposition on the modified porous stainless steel support using rough polishing/$ZrO_2$ powder filling and micro-polishing surface treatment, and following Ag up-filling heat treatment. Because the modified Pd-Ag alloy membranes using rough polishing/$ZrO_2$ powder filling method demonstrate high hydrogen permeability as well as diffusion barrier efficiency, it leads to the performance improvement in hydrogen perm-selectivity. Our membranes, therefore, are expected to be applicable to industrial fields for hydrogen purification and separation owing to enhanced functionality, durability and metal support/Pd alloy film integration.

• 한국구조물진단유지관리공학회 논문집
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• 제24권6호
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• pp.138-145
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• 2020

본 연구는 강재 단순보의 유공보 시스템에서 개구부를 지지점 에 근접한 위치에 설치하는 경우에 대하여 구조성능을 파악하고자 실험을 실시하였다. 또한 수직·수평 강판을 이용한 개구부 보강에 대하여도 실험을 통하여 구조성능을 파악하였다. 강재 단순보에서 개구부가 지지점에 근접한 위치인 강재보 높이의 절반(D/2)인 경우에 강재보 높이(D)인 경우보다 적절한 개구부 위치인 것을 알 수 있었다. 또한 보강방법으로는 수직강판 보강보다는 수평강판 보강이 보강효과가 크며, 개구부와 강판의 간격이 없는 것이 구조성능이 더 큰 결과를 얻을 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.825-831
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• 2010

In this study is stress behavior of steel support structure is to identify basic research. Steel stress due to load step to determine the behavior of steel using strain gauge steel loading test was performed. Numerical analysis and steel loading test using strain gauge on the actual steel stress behavior was analyzed. First, when tensile loading 3.5tonf load side of the plastic behavior appeared. Elastic model, using numerical analysis and comparison of results, the actual value is saved and you can see some difference. This repeated loading tests on steel can be seen from the results of the stress behavior of the steel rather than the elastic behavior of elastic-plastic behavior is because you can see. In addition, the upper and lower steel stress in compression and tension behavior represents the behavior was similar, but different. Steel loading test results, Y-axis get a compression if X-axis is tension. The future based on this study, the stress sensitivity curve of magnetic anisotropy sensor for non-destructive stress measurement technique for the study will be performed. And the behavior of plastic zone and residual stress to determine the numerical analysis using non-elastic model is needed.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1370-1376
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• 2009

Reinforcing steel works should be carefully controlled by the construction manager considering the severe fluctuation of the price of reinforcing steel bars and for the safety of structure in building constructions. In particular, preparing rebar placing drawings needs more effort and time than before because of the emergence of higher and more complicated buildings. Moreover, the experience of field engineers or foremen (fabricators or detailers) in preparing placing drawings gives rise to the differences in fabricated bar type and quantity of bars used. To address these problems, this study proposed the support system in preparing placing drawings for reinforcing steel works efficiency. In the near future, if this system can be made available on the web, multiple end-users will be able to share the result; the efficiency of rebar supply chain management will also be improved.

• Geomechanics and Engineering
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• 제11권2호
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• pp.177-195
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• 2016

To secure the stability of geotechnical infrastructures and minimize failures during the construction process, a number of support systems have been introduced in the last several decades. In particular, stabilization methods using steel bars have been widely used in the field of geotechnical engineering. Rock bolt system is representative support system using steel bars. Pre-stressing has been applied to enhance reinforcement performance but can be released because of the failure of head or anchor sections. To overcome this deficiency, this paper proposes an innovative support system that can actively reinforce the weak ground along the whole structural element by introducing an active tension bolt containing a spring unit to the middle of the steel bar to increase its reinforcement capacity. In addition, the paper presents the support mechanism of the active tension bolt based on a theoretical study and employs an experimental study to validate the performance of the proposed active tension bolt based on a down-scaled model. To examine the feasibility of the active tension unit in a pillar, the paper considers a pullout test and a small-scale experimental model. The experimental results suggest the active tension bolt to be an effective support system for pillar reinforcement.

• 한국강구조학회 논문집
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• 제17권6호통권79호
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• pp.649-660
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• 2005

강박스거더교 다이아프램의 맨홀은 지금까지 경험적으로 설계하여, 강교제작에 과도한 비용을 유발시키는 한 요인이 되고 있다. 다이아프램 맨홀 제작의 경제성과 효율성을 제고시키기 위해서는 다이아프램 맨홀부의 정확한 거동분석을 통한 검토가 필요하다. 본 논문에서는 강상자형교 지점부의 다이아프램 맨홀의 거동 분석을 위해 현장실측과 구조해석이 수행되었다. 여러 가지 맨홀 형상들에 대한 상세 구조해석을 통하여, 강박스거더교의 지점부 다이아프램 맨홀의 적절한 보강방법에 대하여 제안하였다.

• 한국산업정보학회논문지
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• 제14권4호
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• pp.143-152
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• 2009

본 논문은 철강산업의 R&D 역량강화를 위해 IT 부문이 지원할 수 있는 정책을 모색하고 이에 대한 타당성을 검증한 사례연구이다. 기술추격형에서 기술선도형으로의 전환기에 놓여있는 국내 철강산업이 R&D 역량을 강화하기 위해서는 개별 철강사뿐만 아니라 대학, 연구소 등 외부와 개방형 R&D 연계체제를 적극 추진해야 한다. 이러한 상황 하에서 IT가 R&D 역량 강화를 효과적으로 지원하는 역할을 수행해야 한다. 본 연구에서는 이러한 목적을 갖는 IT 분야의 지원정책들을 개발하고 우선순위분석 등을 통해 제안된 정책들의 타당성을 검토하며, Triple Helix관점에서 정부, 기업, 학계의 역할을 논의한다.

• 한국구조물진단유지관리공학회 논문집
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• 제25권2호
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• pp.1-7
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• 2021

강 박스거더 교량의 연속지점부 바닥판은 상부플랜지와 합성되는 구조이며 장경간 교량에서는 지점부 바닥판에 인장균열이 발생할 수 있는 구조로서 내구성 저하 등의 문제가 발생하고 있다. 이는 장경간 적용시 고정하중 및 활하중의 영향으로 슬래브의 교축방향 인장응력이 설계인장강도를 초과하기 때문이다. 이에 지점부 슬래브에 교축방향 철근을 추가하여 인장균열을 제어하고 추가의 압축응력 도입이 필요하다. 이러한 문제점 해결을 위해 연속지점부 상부슬래브의 인장응력 구간에 PS강선 긴장으로 압축응력을 도입하는 강 박스거더교의 구조계를 제안하였고, 이에 따른 구조적 성능을 유한요소해석과 실물시험체의 강선긴장 실험을 통해서 비교 검증하였다. PS강선 긴장을 통해 부모멘트부에 발생하는 슬래브의 인장응력 및 균열을 제어할 수 있는 압축응력을 도입하면 기존 강 박스거더교에 비해 구조안전성 개선 및 내구성능을 강화할 수 있다.

• 콘크리트학회지
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• 제6권3호
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• pp.70-76
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• 1994

• Steel and Composite Structures
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• 제24권1호
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• pp.113-128
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• 2017

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.