• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.609-614
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• 2013

Extended H$\ddot{u}$ckel tight-binding band structure calculations are used to address the chemical bonding and elastic properties of $Zr_2AC$ (A=Al, Si, P, and S). Elastic properties are interpreted by analyzing the density of states and the crystal orbital overlap population for the respective phases. Our results show that the bulk modulus of these ternary compounds is determined by the strength of Zr-A bonds.

• Macromolecular Research
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• 제11권5호
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• pp.393-397
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• 2003

By applying a configurational-bias Gibbs ensemble Monte Carlo algorithm, priority simulation results regarding the conformation of non-dilute polyelectrolytes in solvents are obtained. Solutions of freely-jointed chains are considered, and a new method termed strandwise configurational-bias sampling is developed so as to effectively overcome a difficulty on the transfer of polymer chains. The structure factors of polyelectrolytes in the bulk as well as in the confined space are estimated with variations of the polymer charge density.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.247.2-247.2
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• 2007

• 한국자기학회지
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• 제12권3호
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• pp.83-87
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• 2002

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2009년도 Korea Superconductivity Society Meeting 2009
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• pp.50-50
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• 2009

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.14-16
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• 2009

Surface driven switching of the liquid crystal bulk arising from the coupling between an applied electric field and a polarized state of a nematic liquid crystal, both localized at the substrate surface, is reported. Fast switching is demonstrated in a hybrid aligned nematic cell with a fringe electric field generated by comb-like electrode structure.

• 대한치과보철학회지
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• 제36권1호
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• pp.133-149
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• 1998

Clinical application of composite resin recently draw great concerns in dentistry. Especially due to advantages such as esthetics, adhesiveness, simple clinical procedures, various shapes and kinds of composite resins are widely being applied to prosthodontics, conservative dentistry, and orthodontics. But, clinical problems attributable to the polymerization shrinkage of composite resin have been proposed, and we have to regard clinical problems such as secondary caries, loss of restoration, fracture of the surrounding tooth structure, marginal discoloration, and tooth sensitivity, and many portions are remained to be overcome. Therefore, this study attempts to analyze stress distribution between resin and tooth structure which is generated during polymerization shrinkage of composite resin using three dimensional finite element method. Three dimensional finite element models with conventional box-shape cavity and erosion/abrasion type V-shape lesion cavity in upper central incisor were developed. These cavities were filled with four different types of placement techniques. (bulk filling, horizontal increment filling, oblique occlusal increment filling, oblique gingival increment filling) The stresses generated by polymerization shrinkage of composite resin were calculated. The results analyzed with three dimensional finite element method were as follows : 1. The increment filling technique showed the highest maximum normal stress in both conventional box-shape and V-shape cavities and showed a tendency to decrease after complete polymerization. 2. The bulk filling technique resulted in increased stresses during the curing process in both conventional box-shape and V-shape cavities and the highest maximum normal stress occurred after complete polymerization. 3. The bulk filling resulted in the lowest maximum normal stress in both box-shape and V-shape cavities 4. Regardless of placement method, in conventional box-shape cavity, the maximum normal stress increased in dentin floor, enamel, dentin sequence and in V-shape cavity, the maximum normal stress increased in enamel, dentin sequence.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.20.2-20.2
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• 2011

BMNO dielectric materials with a pyrochlore structure have been chosen and they have quite high dielectric constants about 210 for the bulk material. In the case of thin films, 200-nm-thick BMNO films deposited at room temperature showed a low leakage current density of about $10^{-8}\;A/cm^2$ at 3 V and a dielectric constant of about 45 at 100 kHz. Because high dielectric constant BMNO thin films kept an amorphous phase at a high temperature above $900^{\circ}C$. High dielectric constant BMNO thin films grown at room temperature have many applications for flexible electronic devices. However, because the dielectric constant of the BMNO films deposited at room temperature is still low, percolative BMNO films (i.e., those were grown in a pure argon atmosphere) sandwiched between ultra-thin BMNO films grown in an oxygen and argon mixture have greater dielectric constants than standard BMNO films. However, they still showed a leakage problem at a high voltage application. Accordingly, a new nano-structure that uses BMNO was required to construct the films with a dielectric constant higher than that of its bulk material. The fundamental reason that the BMNO-Bi nano-composite films grown by RF-Sputtering deposition had a dielectric constant higher than that of the bulk material was addressed in the present study. Also we used the graphene as bottom electrode instead of the Cu bottom electrode. At first, we got the high leakage current density value relatively. but through this experiment, we could get improved leakage current density value.

• 한국세라믹학회지
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• 제38권11호
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• pp.993-999
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• 2001

Bao를 첨가한 perovskite 구조 LaSc $O_3$의 생성상과 proton 전도에 대해 연구하였다. La자리에 $Ba^{2+}$를 40 at% 첨가한 조성에서는 입방정 단일상이 생성된 반면, $Ba^{2+}$를 30 at% 이하로 첨가한 조성은 입방정과 사방정이 생성되었다. $N_2$분위기에서 $650^{\circ}C$ 이상의 온도에서는 주로 산소이온에 의한 전도를 나타내었고, 그 이하의 온도에서는 wet 분위기에서 proton 전도가 관찰되었다. 모든 조성의 물질은 30$0^{\circ}C$ 이하에서는 순수한 proton 전도체의 거동을 보였으며, proton에 의한 bulk(grain)의 전도도는 L $a_{0.6}$B $a_{0.4}$Sc $O_{2.8}$의 경우에 가장 높았다.높았다.다.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.5743-5747
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• 2015

본 연구에서는 가스아토마이저로 제조된 Fe계 벌크비정질 합금 분말을 이용하여 제작된 시험편에 레이저 육성용접을 하였고, 인장시험과 경도시험의 실시 및 미세조직을 관찰하여 육성용접 층의 파괴거동을 분석하였다. 인장시험 결과 육성용접층은 탄성변형 후 바로 파괴가 일어났고, 모재는 소성변형 후 파괴가 일어났다. 육성용접층과 모재의 실제 최대인장강도는 각 각 955.9Mpa과 220.4Mpa이다. 육성용접층과 모재의 미소경도는 각 각 $485.5{\pm}21$과 $197.4{\pm}14$ 이었고, 육성용접층은 매우 높은 경도를 갖는다. 모재는 조대한 결정립을 갖는 미세 구조를 나타내었다. 인장시험 후 파단면을 고분해능주사전자현미경으로 관찰한 결과 육성용접층과 모재의 파괴형태는 각각 취성파괴와 연성파괴를 나타내었다.