• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.226-229
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• 2014

In this study, lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of $d_{33}=454pC/N$, the electromechanical coupling factor $k_p=0.51$, the dielectric constant ${\varepsilon}_r=3,657$, the mechanical quality factor $Q_m=239$, and $T_c$(Tetragonal-Cubic) =$90^{\circ}C$ were shown at x= 0.085. ${\Delta}k_p/k_p20^{\circ}C$ and ${\Delta}f_r/f_r20^{\circ}C$ showed the maximum value of -0.255 and 0.111 at $-20^{\circ}C$ and $80^{\circ}C$, respectively. The maximum total-displacement was $60{\mu}m$ under the input voltage of 50 V. As a result, it is considered that lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.

• 한국영어학회지:영어학
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• 제3권2호
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• pp.255-280
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• 2003

The present paper will argue what can be considered to be principled elements of the initial state S/sub 0/ of the Faculty of Language, which are called the Interface Condition (IC), and how far we can take the strongest minimalist thesis (SMT), which aims to offer principled explanation of language in terms of IC and the principle of efficient computation, to linguistic analysis. We will discuss implications of label-free phrase structures, required by the strong version of the Inclusiveness Condition, and possibilities of crash-free syntax, required by the condition of efficient computation. I will point out problems of Chomsky's assumption that an externally Merged expletive there is a head, which, as a probe, undergoes agreement with the goal T. I will present several advantages we obtain if we maintain A and A' distinction, and assume that wh-movement to the outer [SPEC, υ] is an A'-movement like wh-movement to [SPEC, C].

• Interaction and multiscale mechanics
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• 제6권2호
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• pp.237-255
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• 2013

In this paper, a meshfree-enriched finite element method (ME-FEM) is introduced for the large deformation analysis of nonlinear path-dependent problems involving contact. In linear ME-FEM, the element formulation is established by introducing a meshfree convex approximation into the linear triangular element in 2D and linear tetrahedron element in 3D along with an enriched meshfree node. In nonlinear formulation, the area-weighted smoothing scheme for deformation gradient is then developed in conjunction with the meshfree-enriched element interpolation functions to yield a discrete divergence-free property at the integration points, which is essential to enhance the stress calculation in the stage of plastic deformation. A modified variational formulation using the smoothed deformation gradient is developed for path-dependent material analysis. In the industrial metal forming problems, the mortar contact algorithm is implemented in the explicit formulation. Since the meshfree-enriched element shape functions are constructed using the meshfree convex approximation, they pose the desired Kronecker-delta property at the element edge thus requires no special treatments in the enforcement of essential boundary condition as well as the contact conditions. As a result, this approach can be easily incorporated into a conventional displacement-based finite element code. Two elasto-plastic problems are studied and the numerical results indicated that ME-FEM is capable of delivering a volumetric locking-free and pressure oscillation-free solutions for the large deformation problems in metal forming analysis.

• 한국표면공학회지
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• 제36권3호
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• pp.251-255
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• 2003

With increasing environmental demands in surface treatment of steel sheets, the passivation layers containing hexavalent chromium $(Cr^{+6})$ are being replaced by non-chromium or trivalent chromium compounds. After review on the various types of inorganic compounds, the zirconates was chosen as the candidate for alternative to sodium dichromate in the aspect of its barrier properties with excellent adhesion to organics. The ammonium zirconium carbonate (AZC) and sodium hexafluorozirconate (SFZ) could be reach $70-80\%$ level of CDC (cathodic dichromate) treatment by their single applications. But high porosity in the AZC layer and poor electrical conductivity of SFZ solution limit the single application of zirconate. Mixed composition of zirconates to compensate their inferiorities or incorporation of organic compounds to seal the porosity seems to be inevitable to match up the target level of Cr-free passivation of tinplate.

• Journal of Animal Science and Technology
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• 제46권2호
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• pp.193-200
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• 2004

본 연구는 거세우가 1일 필요로 하는 유지를 위한 에너지요구량을 구하기 위해 실시하였다. 유지를 위한 에너지요구량 실험은 6개월령에 거세한 평균체중 376.6$\pm$12.5kg의 한우 9두를 공시하였고, 사료에너지 섭취수준은 배합사료와 볏짚의 비율을 56:44로 하면서 유지 수준(Maintenance)의 약 0.8배(0.8M), 1.2배(1.2M), 1.6배(1.6M) 섭취할 수 있도록 사료급여량으로 조절하여 에너지 균형법에 의해 실시하였다. 대사체중당 총 건물섭취량은 0.8M, 1.2M 그리고 1.6M이 각각 48.5, 64.9그리고 86.5g/$BW^{0.75}$을 섭취한 것으로 나타났고, 에너지 및 단백질의 농도가 같았던 본 시험사료는 건물섭취량을 증가시켜 총에너지 섭취량을 높여도 건물, 유기물, 조단백질, 조섬유, 조지방, 가용무질소물의 소화율에는 영향이 없었다. 평균 대사체중당 총 에너지섭취량은 0.8M, 1.2M, 1.6M에서 각각 190.8, 255.8, 340.9kcal/$BW^{0.75}$이었고, 분으로 손실된 에너지는 총 에너지섭취량의 약 41% 수준, 뇨로 손실된 에너지는 1.5% 이하였다. 또한 반추위 발효과정에서 발생하는 메탄에 의한 에너지 손실은 5${\sim}$9%의 범위였으며, 체열에 의한 손실량은 40${\sim}$60% 이었다. 0.8M, 1.2M, 1.6M의 에너지 수준별 대사에너지 섭취량, 92.6, 134.8, 181.0kcal/$BW^{0.75}$과 각각의 체축적에너지 -20.7, 6.2, 38.5kcal/BW0.75과의 관계식에서 X축 절편값, 즉 유지를 위한 에너지요구량은 대사에너지로 124.3kcal $ME/BW^{0.75}$로 나타났다.