• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.69-70
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• 2008

Micro resonators have been actively investigated for bio/chemical sensors and RF M/NEMS devices. Among various materials, SiC is a very promising material for micro/nano resonators since the ratio of its Young's modulus, E, to mass density, $\rho$, is significantly higher than other semiconductor materials, such as, Si and GaAs. Polycrystalline 3C-SiC cantilever with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and its fundamental resonance was measured by a laser vibrometer in air and vacuum at room temperature, respectively. For the cantilever with $100{\mu}m$ length, $10{\mu}m$width and $1.3{\mu}m$ thickness, the fundamental frequency appeared at 147.2 kHz.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1472-1475
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• 2009

The microfluidics channel were fabricated using thermal roll-imprinting process on plastic substrates. As rollimprinting surface is heated directly at $100^{\circ}C$ and printing process proceed 380/400 kgf pressure, we fabricated microfluidic patterns separated line of $40.04{\mu}m$, serpentine line of $113.89{\mu}m$ and depth of imprint pattern is $15.35{\mu}m$, it means to get fine pattern has more than 70% imprint rate in designed mask.

• Nuclear industry
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• v.37 no.8
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• pp.38-57
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• 2017

이 보고서는 2019년, 2022년, 그리고 2040년에 가동에 들어가는 신규 발전원들의 균등화 발전 비용과 균등화 회피 비용의 평균값이 얼마나 되는지를 보여주는 데 그 목적이 있다. 이 보고서에 나온 자료는 Annual Energy Outlook 2017(AEO2017)를 작성하는 데 이용된 National Energy Modeling System(NEMS)에 있는 것들이다. 세 가지의 시나리오 중에서 2022년 가동에 들어가는 경우에 대해서만 본문에서 다루었고, 나머지 2019년과 2040년 가동에 들어가는 경우에 대해서는 각각 부록 A와 B에서 다루었다. 계산은 NEMS의 전력시장 모듈(EMM)에 들어 있는 미국의 22개 지역에 건설되는 발전 설비들을 대상으로 하고 있다. 이 보고서는 그 22개 지역 발전 설비들의 평균 균등화 발전 비용, 설비 용량을 고려한 가중 평균 비용, 지역 간 비용 편차, 그리고 균등화 회피 비용과 균등화 발전 비용의 차이 등을 계산하여 제시하고 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.346-347
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• 2007

Aluminum nitride (AlN) thin films were deposited on Polycrystalline (poly) 3C-SiC buffer layers using pulsed reactive magnetron sputtering. Characteristics of AlN films were investigated experimentally by means of FE-SEM, X-ray diffraction, and FT-IR, respectively. As a result, highly (002) oriented AlN thin films with almost free residual stress were achieved using 3C-SiC buffer layers. Therefore, AlN thin films grown on 3C-SiC buffer layers can be used for various piezoelectric fields and M/NEMS applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.134-135
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• 2007

Growth of cubic SiC has been carried out on oxided Si substrate using atmospheric pressure chemical vapor deposition (APCVD). Hexamethyldisilane (HMDS) was used as the single precursor and nonflammable mixture of Ar and $H_2$ was used as carrier gas. Epitaxial growth had performed depositions under the various $H_2$ conditions which were adjusted from 0 to 100 seem. The effects of $H_2$ was characterized by surface roughness, thickness uniformity, films quality and elastic modulus. Thickness uniformity and films quality were performed by SEM. Surface roughness and elastic modulus were investigated by AFM and Nano-indentor, respectively. According to the $H_2$ flow rate, Poly 3C-SiC thin film quality was improved not only physical but also mechanical properties.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.702-707
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• 2005

The equations of motion of the structure, which is a small scale cantilever beam considering electrostatic force, squeeze film damping and van der Waals force are obtained employing Galerkin's method based on Euler beam theory. The influence of each force is investigated fur changing the size of a small scale cantilever beam which assumed uniform shape. Also the forces which are affected by the required size of a small scale cantilever beam for manufacturing are forecasted.

• Advances in Computational Design
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• v.7 no.3
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• pp.211-227
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• 2022

In this research, the size-dependent impact of an embedded piezoelectric nanoplate subjected to in-plane loading on free vibration characteristic is studied. The foundation is two-parameter viscoelastic. The nonlocal elasticity is employed in order to capture the influence of size of the plate. By utilizing Hamilton's principle as well as the first- order shear deformation theory, the governing equation and boundary conditions are achieved. Then, using Navier method the equations associated with the free vibration of a plate constructed piezoelectric material under in-plane loads are solved analytically. The presented formulation and solution procedure are validated using other papers. Also, the impacts of nonlocal parameter, mode number, constant of spring, electric potential, and geometry of the nanoplate on the vibrational frequency are examined. As this paper is the first research in which the vibration associated with piezoelectric nanoplate on the basis of FSDT and nonlocal elasticity is investigated analytically, this results can be used in future investigation in this area.

• Advances in nano research
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• v.12 no.6
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• pp.617-627
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• 2022

In the current study, the nonlinear impact of the Von-Kármán theory on the vibrational response of nonhomogeneous structures of functionally graded (FG) nano-scale tubes is investigated according to the nonlocal theory of strain gradient theory as well as high-order Reddy beam theory. The inhomogeneous distributions of temperature-dependent material consist of ceramic and metal phases in the radial direction of the tube structure, in which the thermal stresses are applied due to the temperature change in the thickness of the pipe structure. The general motion equations are derived based on the Hamilton principle, and eventually, the acquired equations are solved and modeled by the Meshless approach as well as a computer simulation via intelligent mathematical methodology. The attained results are helpful to dissect the stability of the MEMS and NEMS.

• Computers and Concrete
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• v.30 no.2
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• pp.151-164
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• 2022

This paper investigates the stability of the functionally graded cylindrical small-scale tube regarding the dynamic analysis and based on the modified nonclassical high-order nonlocal strain gradient theory. The nonlocal beam is modeled according to the high-order tube theory utilizing the energy method based on the Hamilton principle, then the nonlocal governing equations and also nonlocal boundary conditions equations are obtained. The tube structure is made of the new class of composite material composed of ceramic and metal phases as the functionally graded structures. The functionally graded (FG) tube structures rotate around the central axis, and the stability of this nanodevice is due to the centrifugal force which is used for the application of nanoelectromechanical systems (NEMS) is studied in detail.

• Advances in nano research
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• v.15 no.3
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• pp.203-213
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• 2023

The possibility of energy harvesting as well as vibration of a three-layered beam consisting of two piezoelectric layers and one core layer made of nonpiezoelectric material is investigated using nonlocal strain gradient theory. The three-layered nanobeam is resting on an elastic foundation. Hamilton's principle is used to derive governing equations and associated boundary conditions. The generalized differential quadrature method (GDQM) was used to discretize the equations, and the Newmark beta method was used to solve them. The size-dependency of the elastic foundation is considered using two-phase elasticity. The equations, as well as the solution procedure, are validated utilizing some compassion studies. This work can be a basis for future studies on energy harvesting of small scales.