• Advances in nano research
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• 제8권4호
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• pp.323-333
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• 2020

In recent years, there has been an upsurge for the usage of buckling restrained braces (BRB) rather than ordinary braces, as they have evidently performed better. If the overall brace buckling is ignored, BRBs are proven to have higher energy absorption capacity and flexibility. This article aims to deliberate an economically efficient yet adequate type of all-steel BRB, comprised of the main components as in traditional ones, such as : (1) a steel core that holds all axial forces and (2) a steel restrainer tube that hinders buckling to occurr in the core; there is a more practical detailing in the BRB system due to the elimination of a filling mortar. An investigation has been conducted for the proposed rectangular-tube core BRB and it is hysteric behavioral results have been compared to previous researches conducted on a structure containing a similar plate core profile that has the same cross-sectional area in its core. A loss of strength is known to occur in the BRB when the limiting condition of local buckling is not satisfied, thus causing instability. This typically occurs when the thickness of the restrainer tube's wall is smaller than the cross-sectional area of the core plate or its width. In this study, a parametric investigation for BRBs with different formations has been performed to verify the effect of the design parameters such as different core section profiles, restraining member width to thickness ratio and relative cross-sectional area of the core to restrainer, on buckling load evaluation. The proposed BRB investigation results have also been presented and compared to past BRB researches with a plate profile as the core section, and the advantages and disadvantages of this configuration have been discussed, and it is concluded that BRBs with tubular core section exhibit a better seismic performance than the ones with a plate core profile.

• 한국강구조학회 논문집
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• 제21권2호
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• pp.145-154
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• 2009

이 논문에서는 새롭게 제안된 접합부를 적용한 단층 래티스 돔의 비탄성 거동에 대해 실험적으로 분석하였다. 구조적인 성능과 시공성을 모두 만족시키기 위해서 제안된 새로운 접합부를 적용하여 강관으로 구성된 스팬 7m의 단층 래티스 돔의 축소실험모델을 제작하였으며, 각 절점에 균일한 하중이 가력되도록 하중전이장치를 이용하여 정적재하실험을 수행하였다. 최대가력하중은 1,114kN이었고, 일부 접합부의 항복 이후에 강관부재의 좌굴이 발생하였다. 강관부재의 좌굴발생 이후에는 가력장치가 허용할 수 있는 변위까지 실험을 수행하였으며, 실험을 통해서 구해진 단층 래티스 돔의 비탄성거동을 하중 단계별로 분석하였다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.147.1-147
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• 2003

Freesia, a member of the Iridaceae family, has fragant, tubular shaped flowers and is very popular ornamental plants in the world. Diseased freesia plants showing systemic leaf streak mosaic symptoms were collected from a cultivated farm in Kyonggi province, Korea in 2003, and its causal agents were investigated. Two viruses, Cucumber mosaic virus (Fr-CMV) and a potyvirus, were identified from the leaf tissues of the diseased freesia based on sequence analysis and host range tests. CMV-Fr could infect systemically on Chenopodium quinoa, C. amaranticolor, N. glutinosa, and N. benthamiana, and this biological property is distinguishable from ordinary strains of CMV. A filamentous potyvirus-shaped virus could not infect general indicator plants by mechanical inoculation. Single RT-PCR products was successfully amplified with a set of degenerate primers specific to the Potyvirus genus and total nucleic acids from the infected tissues, and was cloned into the pGEMT-Easy vector. Nucleotide sequences confirmed it belongs to the Potyvirus genus with either a new species or an isolate of Freesia mosaic virus (no information is available for the FrMV). This is the first report of FrMV in Korea and more characterizations of the two viruses are in progress.

• 한국강구조학회 논문집
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• 제29권3호
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• pp.237-247
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• 2017

본 연구에서는 각형 강관 내부에 수직 다이아프램이 적용된 CFT 기둥 접합부의 구조적 특성에 대해 알아보았다. 각형 CFT 기둥의 거동을 파악하기 위해 실대형 3개 실험체를 제작하여 실험을 수행하였다. 유한요소해석을 통해 다이아프램의 거동을 확인하였으며 접합부 내력식을 제안하였다.

• Steel and Composite Structures
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• 제15권6호
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• pp.623-643
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• 2013

Concrete filled steel tubular members (CFST) become a popular choice for modern building construction due to their numerous structural benefits and at the same time aging of those structures and member deterioration are often reported. Therefore, actions like implement of new materials and strengthening techniques become essential to combat this problem. The application of carbon fibre reinforced polymer (CFRP) with concrete structures has been widely reported whereas researches related to strengthening of steel structures using fibre reinforced polymer (FRP) have been limited. The main objective of this study is to experimentally investigate the suitability of CFRP to strengthening of CFST members under flexure. There were three wrapping schemes such as Full wrapping at the bottom (fibre bonded throughout entire length of beam), U-wrapping (fibre bonded at the bottom throughout entire length and extended upto neutral axis) and Partial wrapping (fibre bonded in between loading points at the bottom) introduced. Beams strengthened by U-wrapping exhibited more enhancements in moment carrying capacity and stiffness compared to the beams strengthened by other wrapping schemes. The beams of partial wrapping exhibited delamination of fibre and were failed even before attaining the ultimate load of control beam. The test results showed that the presence of CFRP in the outer limits was significantly enhanced the moment carrying capacity and stiffness of the beam. Also, a non linear finite element model was developed using the software ANSYS 12.0 to validate the analytical results such as load-deformation and the corresponding failure modes.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.165-170
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• 2008

본 논문에서는 새로이 제안된 접합부를 가진 단층 래티스 돔의 비탄성 거동을 실험적으로 분석하였다. 구조적인 성능과 시공성을 모두 만족시키기 위해서 제안된 새로운 접합부를 적용하여 강관으로 구성된 스팬 7m의 축소 실험모델을 제작하였으며, 하중 전이장치를 이용하여 각 절점에 균일한 하중이 가력되는 정적 재하실험을 수행하였다. 최대 가력하중은 설계하중의 약 1.6배였으며, 일부 부재에서 압축 항복점을 넘어 비탄성 좌굴이 발생하였다. 좌굴 발생 이후에는 가력장치가 허용할 수 있는 변위까지 실험을 수행하였으며, 실험을 통해서 구해진 래티스 돔의 거동을 구조설계의 관점에서 분석하였다.

• Steel and Composite Structures
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• 제21권4호
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• pp.805-827
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• 2016

A new type of precast CFST column to RC beam braced frame is proposed in this paper. A series of shake table tests were conducted to excite a one-third scale six-story model for investigating the global seismic performance of this type of structure against earthquake actions. Particular emphasis was given to its dynamic property, global seismic responses and failure path. Correspondingly, a numerical model built on the basis of fiber-beam-element model, multi-layer shell model and element-deactivation method was developed to simulate the seismic performance of the prototype structure. Numerical results were compared with the measured values from shake table tests to verify the validity and reliability of the numerical model. The results demonstrated that the proposed novel precast CFST column to RC beam braced frame performs excellently under strong earthquake excitations; the "strong CFST column-weak RC beam" and "strong connection-weak member" anti-seismic design principles can be easily achieved; the maximum deflections of precast CFSTC-RCB braced frame satisfied the deflection limitations proposed in national code; the numerical model can properly simulate the dynamic property and responses of the precast CFSTC-RCB braced frame that are highly concerned in engineering practice.

• Steel and Composite Structures
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• 제35권1호
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• pp.93-109
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• 2020

Developed from conventional concrete filled steel tubular (CFST) members, concrete-encased CFST has attracted growing attention in building and bridge practices. In actual construction, the inner CFST is erected prior to the casting of the outer reinforced concrete part to support the construction preload, after which the whole composite member is under sustained service load. The complex loading sequence leads to highly nonlinear material interaction and consequently complicated structural performance. This paper studies the full-range behaviour of concrete-encased CFST columns with initial preload on inner CFST followed by sustained service load over the whole composite section. Validated against the reported data obtained from specifically designed tests, a finite element analysis model is developed to investigate the detailed structural behaviour in terms of ultimate strength, load distribution, material interaction and strain development. Parametric analysis is then carried out to evaluate the impact of significant factors on the structural behaviour of the composite columns. Finally, a simplified design method for estimating the sectional capacity of concrete-encased CFST is proposed, with the combined influences of construction preload and sustained service load being taken into account. The feasibility of the developed method is validated against both the test data and the simulation results.

• Childhood Kidney Diseases
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• 제1권2호
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• pp.183-188
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• 1997

Familial juvenile hyperuricemic nephropathy is an autosomal dominant disease characterized by progressive renal disease and hyperuricemia or gout, affecting young people of either sex equally. There are two biochemical markers of this disorder. The first is hyperuricemia disproportionate to the degree of renal dysfunction; the second is a grossly reduced clearance of uric acid relative to creatinine, dispropotionate to age, sex and degree of renal failure. We experienced 2 family members with hyperuricemia. One family member, a 13-year-old girl who had suffered from tophaceous gout and chronic renal failure. Her younger brother also had hyperuricemia and moderately reduced renal function. Their urinary excretion fractions of uric acid($FE_{uric\;acid}$) were reduced and renal biopsy specimens showed interstitial fibrosis with tubular atrophy and interstitial urate crystal deposition. We have treated these two patients with allopurinol but we have done renal transplantation because she progressed to end stage renal disease at 16 year old age.

• 한국공간구조학회논문집
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• 제3권2호
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• pp.91-99
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• 2003

The purpose of this study is to analyze the characteristics of the connector having an influence on the elasto-plastic buckling load of ball-jointed single layer latticed domes. As an analytic model, domes are composed of tubular member elements, balls and connectors. The joint system of members in single layer latticed domes has influence on the buckling load. Therefore, in this paper, the variation of the elasto-plastic buckling load by effects of the connectors characteristics is analyzed. The structural behavior of the connector is investigated by following points: (1) the length of rigid zone, (2) looseness of screw and (3) the diameter of connector. In addition, the elasto-plastic buckling analysis is carried out through the variation of the connectors section of yielding part, and then the buckling mode of the dome is examined. As a result, it is emphasized that the characteristics of the connector have significant effects on the buckling load of latticed domes.