• 대한화학회지
• /
• 제53권6호
• /
• pp.671-676
• /
• 2009

밀도 함수이론을 사용해 철 부식 방지제로써 메톨(N-메틸-p-아미노페놀 설페이트)에 대한 기하학적 및 전자구조에 대한 연구가 처음으로 기술되었다. B3LYP/6-31G+(d,p) 기저세트를 사용해 기상 및 액상에서 HOMO, LUMO, 에너지갭 (${\Delta}E$), 멀리칸하전 ($q_M$), 자연원자하전 ($q_n$)과 같은 양자화학적 변수들이 계산되었다. 부식방지메카니즘을 이해하기 위해 부식방지효율과 양자화학적 변수들간의 연관성이 논의되었다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
• /
• pp.333-339
• /
• 2003

Recently, the bridges become greater according to development of a construction technology. This phenomenon requires long span bridge, so that increases the dead weight. The orthotropic steel deck bridges have much advantages such as the light dead weight and the reduction of construction period. And almost whole process of carried out is manufactured at factory, so it can cause the increase of quality authoritativeness. But orthotropic steel deck bridge is consist of structure by welding, it can not avoid a lot of welding jobs, defects and transformation by welding are becoming problem accordingly. Specially, topical stress concentration phenomenon in cross connection area of longitudinal and transverse rib causes fatigue failure. The Bulkhead Plate for prevention of this stress concentration phenomenon was applied by changing the orthotropic steel deck of Williamsburg bridge in USA. But, it is principle that a Bulkhead Plate is not established in the domestic design standard. Therefore, it is estimated that the study for installation of Bulkhead Plate is needed. This treatise with considering these circumstances proves efficiency of Bulkhead Plate and will be presented optimal design details through finite element analysis according to change the geometrical of Bulkhead Plate and tile cross-connection area of longitudinal and transverse rib.

• 한국전산구조공학회논문집
• /
• 제24권4호
• /
• pp.375-382
• /
• 2011

최근 컴퓨터 그래픽 S/W는 변수화 모델링과 생성알고리즘을 제공함으로써 기하학적 표현의 다양성뿐만 아니라 설계자의 의도를 체계적으로 모듈화할 수 있는 여러 가지 가능성을 열어주고 있다. 이 연구에서는 이러한 가능성을 지닌 컴퓨터 그래픽 S/W기반으로 초기 구조형태를 생성하는 방법을 제시하고자 한다. 특히 변수화 모델링과 생성 알고리즘을 이용하여 다양한 설계대안을 생성한다. 더욱이 동적 그래픽스개념을 이용하여 설계자가 한편에서는 구조형태를 생성하는 동안에, 또 다른 한편에서는 상응하는 힘의 흐름도가 마련되도록 한다. 이는 궁극적으로 힘의 흐름에 근거한 합리적 초기 구조형태 설계를 지원하게 될 것이다.

• Earthquakes and Structures
• /
• 제3권5호
• /
• pp.749-766
• /
• 2012

Structural control through integration of passive damping devices within the building structure has been increasingly implemented internationally in the last years and has proven to be a most promising strategy for earthquake safety. In the present paper an alternative configuration of an innovative energy dissipation mechanism that consists of slender tension only bracing members with closed loop and a hysteretic damper is investigated in its dynamic behavior. The implementation of the adaptable dual control system, ADCS, in frame structures enables a dual function of the component members, leading to two practically uncoupled systems, i.e., the primary frame, responsible for the normal vertical and horizontal forces and the closed bracing-damper mechanism, for the earthquake forces and the necessary energy dissipation. Three representative international earthquake motions of differing frequency contents, duration and peak ground acceleration have been considered for the numerical verification of the effectiveness and properties of the SDOF systems with the proposed ADCS-configuration. The control mechanism may result in significant energy dissipation, when the geometrical and mechanical properties, i.e., stiffness and yield force of the integrated damper, are predefined. An optimum damper ratio, DR, defined as the ratio of the stiffness to the yield force of the hysteretic damper, is proposed to be used along with the stiffness factor of the damper's- to the primary frame's stiffness, in order for the control mechanism to achieve high energy dissipation and at the same time to prevent any increase of the system's maximum base shear and relative displacements. The results are summarized in a preliminary design methodology for ADCS.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집B
• /
• pp.404-409
• /
• 2001

Seismic qualification of the Air Cleaning Units for nuclear power plant Ulchin 5&6 has been performed with the guideline of ASME Section III and IEEE 344 code. By using the structural and geometrical similarity analysis, the three models to be analyzed is condensed into a single model and, at the same time, the excitation forces and other operating loads for each model are encompassed with respect to different loading conditions. As the fundamental frequencies of the structure are found to be less than 33Hz, which is the upper frequency limit of the seismic load, response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the structural and electric stability of the major components, modal analysis theory is adopted to derive the required response spectrum at the component locations. As the all combined stresses obtained from the above procedures are less than allowable stresses and no mechanical or electrical failures are found from the seismic testing, the authors confirm the safety of the nuclear equipments Air Cleaning Units studied in this paper.

• 건축역사연구
• /
• 제19권6호
• /
• pp.79-98
• /
• 2010

If we take account of the 'Architectural Tradition' which aims a construction of better environment, we can see that this tradition has ended historically toward Utopia. And the concrete concepts of utopia mainly started on the Renaissance periods. The Utopias were described well in the literatures which contained particularly three representative utopian books in Renaissance period. The one was the most famous novel by Sir Thomas More and the other were by Tommaso Campanella and by Francis Bacon. These novels expressed ideal commonwealths in which inhabitants exist under perfect conditions, ideally perfect places or state of things. The plans of utopia are complete projects of image, its goal is an political, social and economical improvement according to the eras. Their utopias mostly had characteristics as follows; their shape of islands were almost circle, their shape of cities were rectangularity or circle and attached importance to geometrical compositions, their structure of cities were self-sufficiency in closed spaces and their architectural characteristics were uniformity, simplicity and non-ornament. And these architectural characteristics are urban and architectural traditions in communist countries. Also their utopian novels had not much explanations to daily lives of people like as birth, death, relative, mental conflict or authority, money, art. So their utopian novels were not practical and had inappropriate aspects.

• 한국CDE학회논문집
• /
• 제14권5호
• /
• pp.306-313
• /
• 2009

This paper presents the unique formation process of a volumetric space with the digital algorithm developed for Voronoi diagram in order to generate an effective parametric architectural form. By applying systematic parameters of architectural conditions within digital parametric tools, the interactions among sub-spaces developed by Voronoi diagram are enhanced by manipulating the spatial structures. In this paper, we discuss how the parametric distributing and zoning geometrical system can support designers in developing a free-formed space, and research on how this system creates a 3D volumetric space. With the in-depth research on the system and structure of Voronoi diagram, the approaches to the application of Voronoi diagram into architectural form generation are clarified to be an effective, creative and successful digital tool. The result of the application of the Voronoi diagram improves the design quality with systematic language in the sense that the sub-regions are created and controlled under the systematic and balanced hierarchy having dynamic relationships among each others with the restoration of the equilibrium of forces and tensions. This 3-dimensional Voronoi diagram provides another means for designers to solve architectural issues and to reinforce their design concepts.

• Nuclear Engineering and Technology
• /
• 제36권1호
• /
• pp.1-11
• /
• 2004

Two approximate methods for a cosmic radiation shielding calculation in low earth orbits were developed and assessed. Those are a sectoring method and a chord-length distribution method. In order to simulate a change in cosmic radiation environments along the satellite mission trajectory, IGRF model and AP(E)-8 model were used. When the approximate methods were applied, the geometrical model of satellite structure was approximated as one-dimensional slabs, and a pre-calculated dose-depth conversion function was introduced to simplify the dose calculation process. Verification was performed with mission data of KITSAT-1 and the calculated results were also compared with detailed 3-dimensional calculation results using Monte Carlo calculation. Dose results from the approximate methods were conservatively higher than Monte Carlo results, but were lower than experimental data in total dose rate. Differences between calculation and experimental data seem to come from the AP-8 model, for which it is reported that fluxes of proton are underestimated. We confirmed that the developed approximate method can be applied to commercial satellite shielding calculations. It is also found that commercial products of semi-conductors can be damaged due to total ionizing dose under LEO radiation environment. An intensive shielding analysis should be taken into account when commercial devices are used.

• Nuclear Engineering and Technology
• /
• 제37권6호
• /
• pp.525-536
• /
• 2005

The interfacial area transport equation dynamically models the changes in interfacial structures along the flow field by mechanistically modeling the creation and destruction of dispersed phase. Hence, when employed in the numerical thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Accounting for the substantial differences in the transport mechanism for various sizes of bubbles, the transport equation is formulated for two characteristic groups of bubbles. The group 1 equation describes the transport of small-dispersed bubbles, whereas the group 2 equation describes the transport of large cap, slug or chum-turbulent bubbles. To evaluate the feasibility and reliability of interfacial area transport equation available at present, it is benchmarked by an extensive database established in various two-phase flow configurations spanning from bubbly to chum-turbulent flow regimes. The geometrical effect in interfacial area transport is examined by the data acquired in vertical fir-water two-phase flow through round pipes of various sizes and a confined flow duct, and by those acquired In vertical co-current downward air-water two-phase flow through round pipes of two different sizes.

• 한국실내디자인학회논문집
• /
• 제16권6호
• /
• pp.11-18
• /
• 2007

Edward Hopper is one of the great American artists in the 20th Century. In the field of art, it seems that his paintings are thoroughly analyzed In terms of human alienation and emotional aspects in various ways. However, in his numerous paintings, highly interesting spatial aspects can be found. Purpose of this study is to analyze some of his painting by the spatially analytical tools to examine how his space is experienced. The tools are: relationship between each space, relationship between light and space, and geometrical composition. Among many paintings by Hopper, four of the works that depicted interior spaces are selected and further case-studied in detail: ${\ulcorner}$Rooms by the Sea${\lrcorner}$ (1951), ${\ulcorner}$Sun in an Empty Room${\lrcorner}$ (1963), ${\ulcorner}$New York Movie${\lrcorner}$ (1939) and ${\ulcorner}$Automat${\lrcorner}$ (1927). An Environmental Simulation with scale models was used to examine the relation between light and space. After the research, some unique characteristics of his space were found. Even though his paintings seem to represent the everyday spaces, there are fascinating hidden structure to make people experience in a specific way that Hopper created. Spaces In his paintings do not communicate with each other but are constantly interrupted by the element of time. The mundane everyday world is rediscovered and recreated through these multidimensional and heterogeneous space.