반강접 접합부를 고려한 철골 구조물의 2차 탄성 해석 및 최적설계

구본율,박춘욱,강성원,강문명 한국공간구조학회 2003 한국공간구조학회지 Vol.3 No.1

Conventional analysis and design of steel structures are performed using the assumption of a either fully rigid or pinned. However, every steel connection lies in between fully rigid and pinned connection. So, It is important to consider the connection for steel structure design. In this paper Computer-based second-order elastic analysis is used to calculate one story two bay and two story three bay for steel structures with semi-rigid connection. Genetic Algorithms(GAs) and Sequential Unconstrained Minized Technique(SUMT) dynamic programming is used to the method for optimum design of steel structures. The efficiency and validity of the developed continuous and discrete optimum design algorithm was verified by applying the algorithm to optimum design examples.

리모델링 전망 설명회

구본율,Gu, Bon-Yul 한국건축구조기술사회 2001 건축구조 Vol.8 No.4

한국리모델링협회에서는 2001년 9월 7일 부산시 크라운호텔에서 건축물 리모델링산업의 동향 및 전망에 과한 설명회를 개최하였다. 이 설명회에서는 윤영선 건설산업연구원 선임연구위원이 시장동향 및 전망에 관한 주제발표를 진행하고 이어 참가업체 및 지역 공공기관 관계자들의 토론이 이루어졌다. 부산지역의 리모델링 시장은 수도권지역과 비교할 때 시장 활성화가 1년정도 늦어진 것으로 분석되고 있어 최근 지역 업계 및 공공기관을 중심으로 시장분위기가 점차 조성되고 있다. 이날 설명회의 내용을 정리하였다.

저온 공정을 이용한 용액 기반 Sb-doped SnO₂ 투명 전도막의 전기적 및 광학적 특성

구본율,안효진,Koo, Bon-Ryul,Ahn, Hyo-Jin 한국재료학회 2014 한국재료학회지 Vol.24 No.3

Solution-based Sb-doped $SnO_2$ (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process ($300^{\circ}C$) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at $300^{\circ}C$C exhibited the superb electrical (${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$) and optical transmittance (~83.1 %) performances.

전기 방사법을 이용한 플레이크형 LiCoO₂ 나노 분말의 제조

구본율,안건형,안효진,Koo, Bon-Ryul,An, Geon-Hyoung,Ahn, Hyo-Jin 한국분말야금학회 2014 한국분말재료학회지 (KPMI) Vol.21 No.2

Flake-like $LiCoO_2$ nanopowders were fabricated using electrospinning. To investigate their formation mechanism, field-emssion scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. Among various parameters of electrospinning, we controlled the molar concentration of the precursor and the PVP polymer. When the molar concentration of lithium and cobalt was 0.45 M, the morphology of $LiCoO_2$ nanopowders was irregular and round. For 1.27 M molar concentration, the $LiCoO_2$ nanopowders formed with flake-like morphology. For the PVP polymer, the molar concentration was set to 0.011 mM, 0.026 mM, and 0.043 mM. Irregular $LiCoO_2$ nanopowders were formed at low concentration (0.011 mM), while flake-like $LiCoO_2$ were formed at high concentration (0.026 mM and 0.043 mM). Thus, optimized molar concentration of the precursor and the PVP polymer may be related to the successful formation of flake-like $LiCoO_2$ nanopowders. As a results, the synthesized $LiCoO_2$ nanopowder can be used as the electrode material of Li-ion batteries.

온도상승에 따른 H-형강 기둥의 내력에 관한 연구

구본율,장명웅,강문명 한국공간구조학회 2004 한국공간구조학회지 Vol.4 No.1

본 논문은 화재시 온도상승에 따른 H-형강 기둥의 내력에 관한 연구이다. 주요 매개변수는 온도, 세장비와 하중비이다. 온도 상승시 강재의 물리적 특성은 EC3 Part1.2에 따랐다. 온도상승에 따른 국부좌굴의 임계온도는 재료의 항복강도와 판폭두께비가 클수록 더 낮아진다. 균등한 열을 받는 철골 기둥의 내혁 평가는 LRFD에 따른 축력과 강축 및 약축 모멘트에 대하여 고려하였다. This paper shows the study on the capacity of H-shape column at elevated temperature in fire. The main parameters are temperatures, slenderness ratios and load ratios. The physical properties of steel material at elevated temperatures are according to EC3 Part 1.2. The critical temperature of local buckling at elevated temperatures are lower when the yield strength of the material is higher, and when the ratios of width-thickness of plates are larger. The evaluation capacity of uniformly heated steel cloumns were considered to axial forces, moments of strong axis and weak axis to the LRFD.

복합 전기방사법을 이용한 Fe-doped TiO₂/α-Fe₂O₃ 이중구조 나노와이어의 합성 및 자성 특성

구본율,안효진,Koo, Bon-Ryul,Ahn, Hyo-Jin 한국재료학회 2014 한국재료학회지 Vol.24 No.8

We synthesized Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell nanowires(NWs) by means of a co-electrospinning method and demonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of the samples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained after calcination at $500^{\circ}C$ exhibited core/shell NWs consisting of $TiO_2$ in the core region and ${\alpha}-Fe_2O_3$ in the shell region. In addition, the XPS results confirmed the formation of Fe-doped $TiO_2$ by the doping effect of $Fe^{3+}$ ions into the $TiO_2$ lattice, which can affect the ferromagnetic properties in the core region. For comparison, pure ${\alpha}-Fe_2O_3$ NWs were also fabricated using an electrospinning method. With regard to the magnetic properties, the Fe-doped $TiO_2/{\alpha}-Fe_2O_3$ core-shell NWs exhibited improved saturation magnetization(Ms) of approximately ~2.96 emu/g, which is approximately 6.1 times larger than that of pure ${\alpha}-Fe_2O_3$ NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the $TiO_2$ lattice, the size effect of the $Fe_2O3_$ nanoparticles, and the structural effect of the core-shell nanostructures.

용액기반 투명전극 분말 재료 연구 동향

구본율,안효진,Koo, Bon-Ryul,Ahn, Hyo-Jin 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.2

Transparent conducting electrodes (TCEs) are attracting considerable attention as an important component for emerging optoelectronic applications such as liquid crystal displays, touch panels, and solar cells owing to their attractive combination of low resistivity (<$10^{-3}{\Omega}cm$) and high transparency (>80%) in the visible region. The solution-based process has unique properties of an easy fabrication procedure, scalability, and low cost compared to the conventional vacuum-based process and may prove to be a useful process for fabricating TCEs for future optoelectronic applications demanding large scale and flexibility. In this paper, we focus on the introduction of a solution-based process for TCEs. In addition, we consider the powder materials used to fabricate solution-based TCEs and strategies to improve their transparent conducting properties.

溫度上昇에 따른 H-形鋼보의 橫挫屈에 關한 硏究

구본율(Koo Bon-Youl),강문명(Kang Moon-Myung) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.2

This paper shows the parametric study on the lateral-torsional buckling load of beams at elevated temperature. The main parameters are temperature, span-to-depth ratios, load ratios and boundary condition. The physical properties of steel material at elevated temperatures are according to EC3 Part 1.2. The strength of the steel beams in fire show that they are governed by the ratios of lateral length to the radius of gyration about minor axis. The evaluation strength of uniformly heated steel beams were considered to stress, deflection and moments according to the load ratios and the lateral-torsional buckling to the LRFD.

온도상승에 따른 H-형강보의 국부좌굴에 관한 연구

구본율(Bon Youl Koo),강문명(Moon Myung Kang),강성덕(Sung Duk Kang) 한국강구조학회 2004 韓國鋼構造學會 論文集 Vol.16 No.1

SnO₂-CoO/carbon-coated CoO core/shell 나노선 복합체의 합성 및 구조분석

이유진,구본율,안효진,Lee, Yu-Jin,Koo, Bon-Ryul,Ahn, Hyo-Jin 한국분말야금학회 2014 한국분말재료학회지 (KPMI) Vol.21 No.5

$SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites were synthesized by using electrospinning and hydrothermal methods. In order to obtain $SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites, $SnO_2-Co_3O_4$ nanowire composites and $SnO_2-Co_3O_4$/polygonal $Co_3O_4$ core/shell nanowire composites are also synthesized. To demonstrate their structural, chemical bonding, and morphological properties, field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. These results indicated that the morphologies and structures of the samples were changed from $SnO_2-Co_3O_4$ nanowires having cylindrical structures to $SnO_2-Co_3O_4/Co_3O_4$ core/shell nanowires having polygonal structures after a hydrothermal process. At last, $SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites having irregular and high surface area are formed after carbon coating using a polypyrrole (PPy). Also, there occur phases transformation of cobalt phases from $Co_3O_4$ to CoO during carbon coating using a PPy under a argon atmosphere.