• Journal of Magnetics
• /
• 제12권2호
• /
• pp.59-63
• /
• 2007

Ferromagnet/Semiconductor heterostructures have attracted much attention because of their potential applications in spintronic devices. We investigated the electronic structures and magnetism of monolayer Fe on $CuGaSe_2(001)$ by using the all-electron full-potential linearized augmented plane-wave method within a generalized gradient approximation. We considered the monolayer Fe deposited on both the CuGa atoms terminated (CuGa-Term) and the Se atom terminated (Se-Term) surfaces of $CuGaSe_2(001)$. The calculated magnetic moment of the Fe atom on the CuGa-Term was about $2.90\;{{\mu}_B}$. Those of the Fe atoms on the Se-Term were in the range of $2.85-2.98\;{{\mu}_B}$. The different magnetic behaviors of the Fe atoms on two different surfaces were discussed using the calculated layer-projected density of states.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.543-548
• /
• 2006

This paper presents the vibration characteristics of scaffolding structures with a hoist according to payloads. In order to analyze the vibrational and structural characteristics for 20-step scaffolding structure, structural and vibrational characteristics for 2-step scaffolding structure were compared with some experimental results. The numerical results for natural frequencies of scaffolding structures have a good agreement with experimental ones. Through the numerical analysis, firstly, it is shown that the maximum stress of scaffolding structures is lower than von-mises yield criteria when four persons with total weight of 280kgf are working at the top of the scaffolding structures. Secondly vibration characteristics including natural frequencies and modes for scaffolding structures are shown in case of various kinds of moving masses.

• 한국CDE학회논문집
• /
• 제4권2호
• /
• pp.121-126
• /
• 1999

Existing data structures for non-manifold solid modelers use basic dat entities, such as vertex, edge, loop, face, shell, and region to find adjacency relationships. But, no one clearly identified what additional types of data entitles are necessary to represent incidence relationships. In this paper, we classified the boundary information of vertex, edge, face , and region from the 3-D space view. As the results we can clearly define the boundary information required for adjacency relationships. The existing B-rep data structures for solid modeler are compared whether they have the required boundary information.

• Wind and Structures
• /
• 제36권4호
• /
• pp.277-292
• /
• 2023

Low-rise structures are generally immersed within the roughness layer of the atmospheric boundary layer flows and represent the largest class of the structures for which wind loads for design are being obtained from the wind standards codes of distinct nations. For low-rise buildings, wind loads are one of the decisive loads when designing a roof. For the case of cylindrical roof structures, the information related to wind pressure coefficient is limited to a single span only. In contrast, for multi-span roofs, the information is not available. In this research, the numerical simulation has been done using ANSYS CFX to determine wind pressure distribution on the roof of low-rise cylindrical structures arranged in rectangular plan with variable spacing in accordance with building width (B=0.2 m) i.e., zero, 0.5B, B, 1.5B and 2B subjected to different wind incidence angles varying from 0° to 90° having the interval of 15°. The wind pressure (P) and pressure coefficients (C_pe) are varying with respect to wind incidence angle and variable spacing. The results of present numerical investigation or wind induced pressure are presented in the form of pressure contours generated by Ansys CFD Post for isolated as well as variable spacing model of cylindrical roofs. It was noted that the effect of wind shielding was reducing on the roofs by increasing spacing between the buildings. The variation pf Coefficient of wind pressure (C_pe) for all the roofs have been presented individually in the form of graphs with respect to angle of attacks of wind (AoA) and variable spacing. The critical outcomes of the present study will be so much beneficial to structural design engineers during the analysis and designing of low-rise buildings with cylindrical roofs in an isolated as well as group formation.

• Journal of the Korean Physical Society
• /
• 제73권9호
• /
• pp.1370-1376
• /
• 2018

The electronic structures, magnetic properties and half-metallicity in $Zr_2RuZ$ (Z = Ga, In, Tl, Ge, Sn, and Pb) alloys with $AlCu_2Mn-$ and $CuHg_2Ti$-type structures were investigated using first-principles density functional theory (DFT) calculations. The calculations showed that $Zr_2RuIn$, $Zr_2RuTl$, $Zr_2RuSn$, and $Zr_2RuPb$ compounds with $CuHg_2Ti$-type structures were half-metallic ferromagnets with half-metallic band gaps of 0.18, 0.24, 0.22, and 0.27 eV, respectively. The half-metallicity originated from d-d and covalent hybridizations between the transition metals Zr and Ru. The total magnetic moments of the $Zr_2RuZ$ (Z = In, Tl, Sn, and Pb) compounds with $CuHg_2Ti$-type structures were integer values of $1{\mu}B$ and $2{\mu}B$, which is in agreement with Slater-Pauling rule ($M_{tot}=Z_{tot}-18$). Among these compounds, $Zr_2RuIn$ and $Zr_2RuTl$ were half-metals over relatively wide regions of the lattice constants, indicating that these two new Heusler alloys are ideal candidates for use in spintronic devices.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 1992년도 춘계연구발표회 논문개요집
• /
• pp.20-21
• /
• 1992

• Structural Engineering and Mechanics
• /
• 제9권2호
• /
• pp.111-126
• /
• 2000

Truss type structures are attractive to a variety of engineering applications on earth as well as in space due to their high stiffness to mass ratios and ease of construction and fabrication. During the service life, an individual member of a truss structure may lose load carrying capacity due to many reasons, which may lead to collapse of the structure. An analytical and computational procedure has been developed to study the response of truss structures subject to member failure under static and dynamic loadings. Emphasis is given to the dynamic effects of member failure and the propagation of local damage to other parts of the structure. The methodology developed is based on nonlinear finite element analysis technique and considers elasto-plastic material nonlinearity, postbuckling of members, and large deformation geometric nonlinearity. The pseudo force approach is used to represent the member failure. Results obtained for a planar nine-bay indeterminate truss undergoing sequential member failure show that failure of one member can initiate failure of several members in the structure.

• 경영과정보연구
• /
• 제21권
• /
• pp.99-114
• /
• 2007

According as Internet based EC(Electronic Commerce) has been activated, More requirements for exchanging digital documents are being proposed in B2B(Business to Business) and B2G(Business to Government) environments. However, the documents can not be processed automatically, because the structures of documents in each site(companies, central/local governments) do not match. Therefore, W3C(World Wide Web Consortium) has proposed XML(eXtensible Markup Language) DTD(Document Type Declaration) technology to support structuring documents. The XML DTD technology can support interoperability between EC sites. And, XML DTD based documents can be processed automatically in every sites. They will improve efficiency of services in B2B and B2G environments. In this paper, we propose interoperable DTD architecture and IDEP(Interoperable DTD Exchange Protocol) protocol which supports searching DTDs and exchanging DTDs. This technology can popularize DTDs and digital documents.

• Journal of Plant Biotechnology
• /
• 제34권3호
• /
• pp.223-227
• /
• 2007

제주상사화의 잎 및 뿌리 조직으로부터 형성된 캘러스 및 구형 소자구로부터 효율적인 기내 식물체 재생체계를 확립하였다. 2,4-D가 첨가된 B5 배양배지에서 12주 배양 후 제주상사화의 잎 조직으로부터 백색의 구형 세포괴 및 캘러스가 동시에 발달하였으며 그 빈도는 32.1%이었다. 그러나 3 mg/L 이상의 고농도 2,4-D 처리구에서는 캘러스 형성빈도가 14%로 크게 감소하였으며 10 mg/L 2,4-D 처리구에서는 캘러스 형성이 전혀 이루어지지 않았다. 잎 조직과 달리 뿌리 절편의 경우 3 mg/L 2,4-D 처리구에서 캘러스 형성빈도가 36.1%로 가장 높았으며 BA 단독처리구나 2,4-D와 BA의 혼용처리구에서는 그 빈도가 감소하였다. 형성된 백색의 구형세포괴는 생장조절제가 첨가되지 않은 B5배지에 배양하면 소자구 발달 경로를 거쳐 소식물체로 발달이 이루어졌다. 소식물체는 생장조절제가 첨가되지 않은 1/2MS 기본배지로 옮겨 명배양한 결과, 약 배양 2주후부터 녹색의 잎이 신장되는 것을 관찰 하였으며 4주 후 뿌리 발달이 이루어지면서 정상적인 식물체로 발달하였다. 재생된 소식물체는 배양기내에서 순화과정을 통해 토양이식이 가능하였다. 본 연구에서 확립된 제주상사화의 식물체 재생체계는 제주상사화의 대량증식 수단은 물론, 유용 형질 도입을 통한 분자육종의 수단 및 유용 유전자원의 장기보전을 위한 초저온 보존 연구의 직접적인 연구소재로 활용이 가능할 것으로 예상된다.

• Structural Engineering and Mechanics
• /
• 제49권2호
• /
• pp.163-182
• /
• 2014

Safety factors proposed in codes CEB, B.A.E.L 91 and EUROCODE 1 cover a great number of uncertainties; making them inadequate for the assessment of existing structures. Suitable safety factors are established using a probabilistic assessment, once real dimensions, materials strength and existing structures deterioration mechanisms are taken into account. This paper presents a calibration method for safety factors using a typical set of RC bridges in France. It considers the principal stages of corrosion provoked by $CO_2$ and $Cl^-$ penetration and threshold indexes (${\beta}_0$) for existing structures. Reliability indexes are determined by the FORM method in the calibration method.