전기방전소결에 의해 제조된 다공성 및 다공성 표면을 갖는 Ti-6Al-4V 임플란트 : (2) 경도 및 압축강도

현창용,허재근,이원희,Hyun, C. Y.,Huh, J. K.,Lee, W. H. 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.5

Porous and porous surfaced Ti-6Al-4V implant compacts were fabricated by electro-discharge-sintering (EDS) of atomized spherical Ti-6Al-4V powders with a diameter of $100-150\;{\mu}m$, The solid core formed in the center of the compact after discharge was composed of acicular ${\alpha}+{\beta}$ Widmanstatten grains, The hardness value at the solid core was much higher than that at the particle interface or particles in the porous layer, which can be attributed to both heat treatment and work hardening effects induced from EDS, The compressive yield strength was in a range of 19 to 436 MPa which significantly depends on both input energy and capacitance, Selected porous-surfaced Ti-6Al-4V implant compacts with a solid core have much higher compressive strengths compared to the human teeth and sintered Ti dental implants.

폐 스테인레스강 단섬유로 강화한 알루미늄 복합분말의 자기펄스압 성형 및 소결 특성

현창용,원철현,박재순,Hyun, Chang-Yong,Won, Chul-Hyun,Park, Jae-Soon 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.6

Characteristics of Al-based composites with waste stainless steel short fiber, fabricated by magnetic pulsed compaction and sintering were investigated. The compacts prepared by magnetic pulsed compaction showed high relative density and homogeneous microstructure compared with that by conventional press compaction. The relative density of sintered composites at $430^{\circ}C$ for 1 h exhibited the same value with compacts and decreased with increase in STS short fiber content. The reaction between Al and STS phase was confirmed by the microstructural analysis using EDS. The sintered composites, prepared by magnetic pulsed compaction, showed increased hardness value with increasing STS fiber content. Maximum yield strength of 100 MPa and tensile strength of 232 MPa were registered in the AI-based composite with 30 vol% STS short fiber.

전기방전소결에 의해 제조된 다공성 Titanium 임플란트의 기계적 특성

현창용,허재근,이원희,Hyun, C.Y.,Huh, J.K.,Lee, W.H. 한국재료학회 2006 한국재료학회지 Vol.16 No.3

Porous surfaced Ti implant compacts were fabricated by electro-discharging-sintering (EDS) of atomized spherical Ti powders. Powders of $50-100{\mu}m$ in diameter were vibratarily settled into a quarts tube and subject to a high voltage and high density current pulse in Ar atmosphere. Single pulse of 0.7 to 2.0 kJ/0.7 gpowder, from 150, 300, and $450{\mu}F$ capacitors was applied in less than $400{\mu}sec$ to produce twelve different porous-surfaced Ti implant compacts. The solid core formed in the center of the compact shows similar microstructure of cp Ti which was annealed and quenched in water. Hardness value at the solid core was much higher than that at the particle interface and particles in the porous layer, which can be attributed to both heat treatment and work hardening effects induced by EDS. Compression tests were made to evaluate the mechanical properties of the EDS compacts. The compressive yield strength was in a range of 12 to 304MPa which significantly depends on input energy. Selected porous-surfaced Ti-6Al-4V dental implant compacts with a solid core have much higher compressive strengths compared to the human teeth and sintered Ti dental implants fabricated by conventional sintering process.

전기방전소결에 의해 제조된 다공성 및 다공성 표면을 갖는 Ti-6Al-4V 임플란트 : (1) 제조방법 및 기본적 특성

현창용,허재근,이원희,Hyun, C. Y.,Huh, J. K.,Lee, W. H. 한국분말야금학회 2005 한국분말재료학회지 (KPMI) Vol.12 No.5

Implant prototypes with various porosities were fabricated by electro-discharge-sintering of atomized spherical Ti-6Al-4V powders. Single pulse of 0.75 to 2.0 kJ/0.7 g-powder, using 150, 300, and $450{\mu}F$ capacitors was applied to produce a fully porous and porous surfaced implant compact. The solid core formed in the center of the compact after discharge was composed of acicular ${\alpha}+{\beta}$ grains and porous layer consisted of particles connected in three dimensions by necks. The solid core and neck sizes increased with an increase in input energy and capacitance. On the other hand, pore volume decreased with increased capacitance and input energy due to the formation of solid core. Capacitance and input energy are the only controllable discharge parameters even though the heat generated during a discharge is the unique parameter that determines the porosity of compact. It is known that electro-discharge-sintering of spherical Ti-6Al-4V powders can efficiently produce fully-porous and porous surfaced Ti-6Al-4V implants with various porosities in a short time less then 400 isec by manipulating the discharging condition such as input energy and capacitance including powder size.

저진공 분위기 전기방전소결에 의해 제조된 다공성 Ti-6Al-4V 임플란트의 표면특성 연구

현창용,허재근,이원희,Hyun, C.Y.,Huh, J.K.,Lee, W.H. 한국재료학회 2006 한국재료학회지 Vol.16 No.3

A single electro-discharge-sintering (EDS) pulse (1.0 kJ/0.7 g), from a $300{\mu}F$ capacitor, was applied to atomized spherical Ti-6Al-4V powder in a low vacuum to produce porous-surfaced implant compacts. A solid core surrounded by a porous layer was formed by a discharge in the middle of the compact. XPS (X-ray photoelectron spectroscopy) was used to study the surface characteristics of the implant material. C, O, and Ti were the main constituents, with smaller amounts of Al, V, and N. The implant surface was lightly oxidized and was primarily in the form of $TiO_2$ with a small amount of metallic Ti. A lightly etched EDS implant sample showed the surface form of metallic Ti, indicating that EDS breaks down the oxide film of the as-received Ti-6Al-4V powder during the discharge process. The EDS Ti-6Al-4V implant surface also contained small amounts of aluminum oxide in addition to $TiO_2$. However, V detected in the EDS Ti-6Al-4V implant surface, did not contribute to the formation of the oxide film..

청소년시설의 이용집단별 건축프로그램 영향인자분석 - 천안시 청소년수련관 프로젝트를 중심으로 -

현창용(Hyun, Chang-Yong),류수훈(Ryu, Soo-Hoon) 한국교육시설학회 2020 敎育施設 Vol.27 No.2

공간구문론을 통한 국내 공공청사시설 공간구조의 연대기적 분석

현창용(Chang-Yong Hyun),최윤경(Yoon-Kyung Choi) 한국생태환경건축학회 2021 한국생태환경건축학회 논문집 Vol.21 No.2

손상된 Rod Type Coupler 주강재의 보수용접에 따른 열영향부특성

현창용(Hyun Chang-Yong),박수중(Park Soo-Choong) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

Cast steels have been mainly in rod type couplers which connect railway vehicles. These components, as important members, are exposed to repeat to repeated stresses and impact loading during stop and departure service for a long tie. The coupler suffers fatigue crack initiations and demage that cause need to repair weldment due to these loading conditions. Therefore, the heat affected zone of cast steel couple in rod type were evaluated in view of metallurgical weld characteristics after repair welding at laboratory. The specimens with two different welding techniques were evaluated after several welding conditions and post-heat treatments. Micro-vickers hardness and tensile tests and microstructural observations were conducted on heat affected zone of the weldment according to repair weld and post-heat treatment.

카즈요 세지마의 작품에 나타나는 건축은유에 관한 연구

현창용(Hyun Chang-Yong),최윤경(Choi Yoon-Kyung),전영훈(Jeon Young-Hoon) 대한건축학회 2011 대한건축학회논문집 Vol.27 No.7

This dissertation focuses on finding negative architectural matters in contemporary formalism and proposing an architectural metaphoric theory as an alternative. Firstly, metaphoric theories in linguistics are clarified. Based on the results of analysis about notions of linguistic and architectural metaphor, this study analyzes Kazuyo Sejima’s works. Through analyzing results of Sejima’s design works reveal her metaphoric presentation structure and establishes her potentiality about metaphor in spatial dimension. Sejima’s new senses in architecture spaces are able to advise to contemporary architecture’s formalism that has absence of spatial meaning.

공공청사시설 공간구조의 유형별 특성에 관한 연구

현창용 ( Hyun Changyong ),이재영 ( Lee Jaeyoung ) 한국공간디자인학회 2020 한국공간디자인학회논문집 Vol.15 No.7

(연구배경 및 목적) 공공건축물은 조성에 소비된 공적자본의 제공자이자 권리자인 시민들의 자유로운 이용 가능성을 담보하지만, 한편으로 대부분의 공공건축물들은 정치적, 행정적 업무의 수행 근거점으로서 보안을 위한 행위의 제한이 요구되기도 한다. 본 연구에서는 이러한 공공청사시설이 제공하는 대민 서비스공간의 구성 방식에 따라 시민들이 경험하게 되는 공간적 양상이 달라짐을 밝히고, 이를 뒷받침할 수 있는 다양한 논거를 통해 바람직한 공공청사시설 공간이 가져야 하는 구조적 특징을 도출하고자 한다. 나아가 이를 정량적 결과를 함축하는 공간구조 분석 방식을 통해 밝힘으로서 국내 공공청사시설이 가지는 대민공간을 건축적으로 진단함에 목적이 있다. (연구방법) 본 연구는 2000년대 이후에 건립된 대표적인 국내 지자체 공공청사시설 중 도면분석이 가능한 사례를 추출해 연구의 대상으로 삼는다. 이러한 공간적 범주에 대한 구조적 특질을 도출하기 위해 대민공간의 구성방식에 따라 사례를 유형화 하고, 각 사례별 대민공간의 시지각환경을 분석해 정량화 된 지표들을 설정한다. 각 지표들은 크게 공간구문론(Space Syntax)에 근거해 공간의 위상도를 가시장그래프(Visual Graph Analysis)를 통해 분석하는 방식과 대민공간의 진입부에서 시선의 조우가 가능한 영역을 아이소비스트(Isovist) 영역으로 환원해 산출하는 방식으로 크게 나뉘어지며, 각 분석을 통해 공공청사시설의 대민공간에서 보여지는 공간구조의 특싱을 규명하고 값을 비교 분석한다. (결과) 단일건축물 내 유, 무형의 방법으로 두 대민공간을 분리한 조닝형의 물리적, 시각적 개방성은 낮으나 도시적 속성으로 인해 능동적 경험이 요구되는 공간구조임을 의미한다고 할 수 있다. 이보다 조금 더 일차원적이고 직접적으로 분리한 분리형의 경우 순수 대민 공간이 별도로 추출됨으로서 개방과 통제, 자율성과 감시 모두 중간적인 성격을 갖게 되었음을 알 수 있었다. 통합형의 경우 물리적, 시각적으로 개방적인 구조이나 전이단계 자체는 소거되고 통합홀이 기하학적 중심공간을 갖게 됨으로서 단순하고 쉬우나 다양성이 축소된 동질화된 공간으로 해석된다. (결론) 본 연구는 국내 공공청사시설의 유형화 지표를 제안하였으며, 그 사회적 의미와 공유점을 파악할 수 있는 키워드를 도출하였음에 의의가 있다. 또한 이를 통해 열린 공공청사시설의 의미과 공공영역의 관계에 대해 논하였음에도 역시 의미가 있다 하겠다. (Background and Purpose) Public buildings ensure the free use of public capital consumed in the creation of public buildings, but on the other hand, most public buildings require restrictions on acts for security as a basis for carrying out political and administrative work. In this study, it is intended to reveal that the spatial aspects that citizens experience vary depending on the way these public office facilities are constructed, and to derive the structural features that should have desirable public office space through various arguments to support them. Furthermore, the purpose of the project is to diagnose the public space of domestic public office facilities in an architectural manner by brightening it through a spatial structure analysis method that implies quantitative results. (Method) This study extracts cases of drawing analysis from representative local government public office facilities built after the 2000s and uses them as subjects of research. In addition, cases are categorized according to the method of composition of public spaces, and quantified indicators are established by analyzing the visual perception environment of public spaces for each case. Each indicator is largely divided into a method of analyzing the topography of space based on Space Syntax and a method of reducing the area of eye contact from the entry part of the public space to the Isovist area. Through each analysis, the specialization of spatial structure shown in the public space is analyzed. (Results) Although the physical and visual openness of the zoning type, which separates the two public spaces in a single building by tangible and intangible methods, is low, it can be said that it is a space structure that requires active experience due to its urban nature. In the case of a slightly more one-dimensional and direct separation, it could be seen that the pure public space was extracted separately, resulting in an intermediate character of both opening and control, autonomy and monitoring. In the case of an integrated type, the physical and visually open structure or transition phase itself is eliminated and the integrated hole has a geometric center space, which translates into a homogeneous space with a simple, easy, but reduced variety. (Conclusions) This research suggests a tangible index of domestic public office facilities, and it is meaningful that keywords were derived to identify the social meaning and sharing points. It is also meaningful to discuss the meaning of public office facilities and the relationship between the public sector.