• 대한금속재료학회지
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• 제46권12호
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• pp.830-834
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• 2008

NiSi is currently being employed in 45 nm CMOS devices as a contact material. We employed a first principles calculation to understand the movements of atoms when Co, Pd, and Pt were added to tetragonal-NiSi on Si (001). The Ni atoms in the tetragonal-NiSi/Si (001) favored away from the original positions along positive c-direction in a systematic way during the energy minimization. Two different Ni sites were identified at the interface and the bulk, respectively. The Ni site at the interface farther away from the interface was more favorable for Pd and Pt substitution. Co, however, prafered the bulk site to the interface site, unlike Pd and Pt.

• Educational Technology International
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• 제10권2호
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• pp.29-61
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• 2009

The purpose of this study was to design an inquiry supporting tool on wiki based collaborative learning and to investigate the effect of the inquiry supporting tool. Eight design principles were selected and more specified design strategies were made from the literatures. The first system with the first-round design principles was developed and implemented in an actual classroom. After the first field study, researcher found a few drawbacks of the system. The second system was implemented in the classroom again. Finally developed wiki-based inquiry supporting tool system is unique in that it allows instructors to design their own CSCL inquiry activities, and it has intuitive menu tabs showing inquiry learning processes.

• 고전문학과교육
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• 제15호
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• pp.113-138
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• 2008

Because of difference of syntactic construction, Lee dong- baek's divides into two parts. Though each parts show different principles of thinking, they aim same communicational purpose. The first half of that quotes set phrase of Chinese classical literature and folklore shows principles of expression that represent object by present cultural well-acquainted informations. It reflects process of thinking basing on cultural identity in pursuit of harmonious communication with listener. In the latter half of the work, the object is presented by mimesis and sensuous description. It implicates intention of making correspondence between linguistic sign and object, and shows principles of expression that present more directly by strengthening the motivated between sign and object. Based on discussion above, I hope we will find a clue to make contents of Korean expression education. We will convert these principles of pursuing cultural universality to make sympathy in communication and pleasure of that, or of representing object substantially to make correspondence into the contents of Korean expression education.

• 비교교육연구
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• 제24권1호
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• pp.249-271
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• 2014

본 논문은 메이지기(明治期) 일본에 서구교육학이 소개되는 과정에서 삼육(三育)의 개념이 어떻게 도입되고 전개되고 있는가를 밝히는 것을 목적으로 한다. 즉 서구의 교육학 서적의 번역을 통해 삼육 관련 용어가 어떻게 번역되고 그 개념이 어떻게 정리되는가를 확인하는 작업이다. 이 글에서 얻어진 결론은 다음과 같다. 첫째로 일본 메이지기 삼육 개념의 도입은 일본사회의 내부적 변화에 따른 선택적 번역과 수용의 과정에 따라 1880년대에는 '삼교(三敎)'의 형태에서 '삼육(三育)'의 체계로서 정착된다. 둘째, 일본 메이지기 삼육의 개념은 일본 교육사조의 흐름에 따라 '삼육'의 형태는 유지하되 교육의 목적에 따라 중점을 두는 구성요소와 개념이 변용되어 전개된다.

• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.41-44
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• 2008

NiSi is less stable than the previously-used $CoSi_2$ at high temperature. Some noble metals, such as Pd and Pt, have been added to NiSi to improve its thermal stability. We employed a first principles calculation to understand the Pd segregation at the interface. An orthorhombic structure of NiSi was used to construct an orthorhombic-NiSi/Si (010). Lattice parameters along a- and c-axes in orthorhombic-NiSi were matched with those of Si for epitaxy contact. The optimized $1\times4\times1$ orthorhombic-NiSi (010) and $1\times2\times1$ Si (010) superstructures were put together to construct the orthorhombic-NiSi/Si (010), and the superstructure was relieved in calculation to minimize its total free energy. The optimized interface thickness of the superstructure was $1.59\AA$. Pd atom was substituted in Ni and Si sites located near interface. Both Ni and Si sites located at the interface were favorable for Pd substitution.

• Journal of Magnetics
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• 제6권3호
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• pp.80-82
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• 2001

We have investigated magnetism of $Fe_2 /Ir_4$(001) superlattice in terms of a first-principles calculation by using an all-electron full-potential linearized augmented plane-wave (FLAPW) method within the generalized gradient approximation (GGA). We considered two magnetic states, the ferromagnetic (FM) and antiferromagnetic (AFM) coupled states between the Fe layers. It was found that the FM state was energetically more stable than the AFM one by 0.166 eV. Calculated magnetic moments of the Fe layers were, in absolute values, 2.45$\mu_B$ and 2.30 $\mu_B$for the FM and AFM states, respectively. We also found that the Ir layers had very small magnetic moments less than 0.1 $\mu_B$ for both magnetic states. In all the magnetic states, the subinterface Ir layers were coupled antiferromagnetically to the interface Ir layers, while the interface Ir layers were always coupled frerromagnetically to the interface Fe layers. These results contradicted to recent experimental reports of magnetically "dead"Fe layers in Fe/Ir superlattices for which the Fe layer thickness was less than two atomic layers. We attributed that the experimentally observed "dead"Fe layers were due to possible interdiffusion between Ir and Fe layers.en Ir and Fe layers.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.611-617
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• 2021

The mechanical properties of α-Na₃(U_0.84(2),Na_0.16(2))O₄ have been researched using the first-principles calculations combined with the quasi-harmonic Debye model. The obtained lattice parameters agree well with the published experimental data. The results of elastic constants indicate that α-Na₃(U_0.84(2),Na_0.16(2))O₄ is mechanically stable. The polycrystalline moduli are predicted. The results show that the α-Na₃(U_0.84(2),Na_0.16(2))O₄ exhibits brittleness and possesses obvious elastic anisotropy. The hardness shows that it can be considered a "soft material". Furthermore, the Debye temperature θ_D and the minimum thermal conductivity k_min are also discussed, respectively. Finally, the thermal expansion coefficient α, isobaric heat capacity C_P and isochoric heat capacity C_V are evaluated through the quasi-harmonic Debye model.

• 대한기계학회논문집A
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• 제33권8호
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• pp.733-738
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• 2009

Mechanical properties of <001> silicon nanowires are presented. In particular, predictions from the calculations based on different length scales, first principles calculations, atomistic calculations, and continuum nanomechanical theory, are compared for <001> silicon nanowires. There are several elements that determine the mechanics of silicon nanowires, and the complicated balance between these elements is studied. Specifically, the role of the increasing surface effects and reduced dimensionality predicted from theories of different length scales are compared. As a prototype, a Tersoff-based empirical potential has been used to study the mechanical properties of silicon nanowires including the Young's modulus. The results significantly deviates from the first principles predictions as the size of wire is decreased.

• 건축역사연구
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• 제14권3호
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• pp.103-118
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• 2005

This study is about the meaning of wooden brackets that are distinctive elements of wooden architecture in Korea, Japan, and China. Existing studies about wooden brackets have been limited to the boundary of formalism, so the object of this study is to make a breakthrough in the field of those studies. The Wooden brackets in this study are considered to be decorative elements, and the principles of their design are examined. The specific subject of the study is wooden architecture with Jusimpo-styled brackets that have brackets only on pillars. The definition of Jusimpo is reexamined first, and ChulMok-Ikkong which has not been regarded as a Jusimpo-styled wooden bracket is interpreted as Jusimpo-styled one in this study. Categorized into three types, Jusimpo is examined how it is expressed according to the type of the roof in a building. In view of the results, the wooden bracket system is an effective technique to express the formality, and two designing principles can be seen in Jusimpo; one that wooden brackets observed externally are standardized and regarded as the same ones, and the other that the style of wooden brackets used in the most formal building is Yi-ChulMok. These designing principles mean that the carpenter who was in charge of building the architecture had certain principles when expressing wooden brackets as well as the roofs according to the class of the architecture. In addition, although the styles of wooden brackets that were used in the most formal architecture during the Chosun period were mostly Dapo, Jusimpo in the form of Yi-ChulMok was also adopted in some temples depending on their scale, and that means Jusimpo-styled wooden brackets were never considered to be inferior to Dapo-styled ones. And this point leaves the argument that the reexamination of Jusimpo-styled wooden brackets which have been regarded as the style used in the attached building or small structures since the Choun dynasty should be conducted.

• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.510-514
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• 2011

Based on first-principles LCAO method, we study the electronic and atomic structures of DNA nucleobases adenine (A), thymine (T), guanine (G), and cytosine (C) adsorbed on graphene surfaces. The ${\pi}-{\pi}$ stacking interactions between graphene and nucleobases lead to the bilayer geometries similar to the Bernal stacked graphite. Through the density of states and charge density analyses, it is found that nucleobases are physisorbed on graphene by dispersive interactions with negligible charge exchange. Our calculations reproduce the atomic structures obtained in previous plane wave calculations accurately with much less computation, and well describe the delocalized ${\pi}-{\pi}$ interactions in graphene-nucleobases system, indicating that the LCAO method is very efficient for investigating graphene-bio systems.