• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.93-94
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• 2014

본 논문의 주제는 가파도 마이크로 그리드에 적용한 1MVA급 배터리 에너지 저장시스템(BESS-Battery Energy Storage System)을 소개하는 것이다. 에너지 저장장치가 디젤발전기와의 연계 및 독립운전 하여 탄소 배출 없이(Carbon-Free) 가파도 전체 부하에 전원을 공급하는 실증 사례를 살핀다.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2243-2248
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• 2011

Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of dimedone, aromatic aldehydes, and a nitrogen source (ammonium acetate or aromatic amines) under solvent-free conditions, giving rise to 1,8-dioxodecahydroacridines in high yields. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents.

• Steel and Composite Structures
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• 제19권5호
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• pp.1259-1277
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• 2015

In this work, a trigonometric refined beam theory for the bending, buckling and free vibration analysis of carbon nanotube-reinforced composite (CNTRC) beams resting on elastic foundation is developed. The significant feature of this model is that, in addition to including the shear deformation effect, it deals with only 3 unknowns as the Timoshenko beam (TBM) without including a shear correction factor. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are assessed by employing the rule of mixture. To examine accuracy of the present theory, several comparison studies are investigated. Furthermore, the effects of different parameters of the beam on the bending, buckling and free vibration responses of CNTRC beam are discussed.

• 한국생산제조학회지
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• 제7권1호
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• pp.75-81
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• 1998

We have studied internal quality including chemical compositions, microscopic structure and nonmetallic inclusion of test materials. We have analyzed tensile strength value, hardness value, impact value etc. In analyzing internal quality, all of the test materials showed typical ferrite+pearlite structure. But nonmetallic inclusion showed oxide and sulfide inclusions in medium carbon steels, and sulfide inclusion is S-free cutting steels. In ca+ S-free cutting steels, the calcium aluminate and sulfide complex inclusion had low-melting points as deformation of sulfide and oxide inclusion is existed. It was found that tensile strength and hardness give maximum value in medium carbon steels, where as minimum in Ca + -free cutting steels. But values of elongation, reduction of area impact are reverse. Fracture surface of impact specimen is ductile in free cutting steels but brittle in medium cabon steels.

• Elastomers and Composites
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• 제34권3호
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• pp.222-228
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• 1999

본 연구에서는, 화학적 표면처리에 따른 카본블랙의 표면, 흡착, 그리고 미세구조의 성질과 물리적 표면 자유에너지를 고찰하였다. 실험적 결과를 통하여, 염기성 용액으로 표면 처리한 경우 pH와 비표면적의 변화 없이 표면 자유에너지의 비극성 또는 극성요소의 증가를 가져왔다. 반면에 산성표면처리의 경우에는 표면특성, 흡착성질과 미세구조의 큰 변화를 확인하였다. 특히, 염기성 처리된 카본블랙은 비극성이나 비표면적의 중요한 인자로 표면 자유에너지의 London 비극성 요소의 증가를 볼 수 있었다. 이는 카본블랙/고무 복합재료에 있어서, 카본블랙이 강화재의 역할 뿐 아니라 분산력 발달에 중요한 역할을 담당하고 있기 때문으로 사료된다.

• Composites Research
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• 제31권6호
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• pp.379-384
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• 2018

본 연구에서는 동일한 표면 형태를 가지는 탄소섬유에 다양한 사이징제를 처리함에 따라 발생하는 에폭 시 수지의 유동 특성 변화를 분석하였다. 동적 접촉각(DCA) 측정을 통해 단일 탄소섬유의 젖음성(Wettability)을 측정하였다. DCA 측정 결과와 함침 특성 간의 연관성을 살피기 위해 Wicking test와 VARTM test를 수행하였다. 추가적으로, 탄소섬유의 표면 에너지 등 다양한 표면 특성을 분석하였으며 Micro-droplet test를 통해 수지와 탄소섬유계면의 계면전단강도를 측정하였다. 이러한 실험 결과를 기반으로, 함침 속도의 증대를 위해서는 탄소섬유의 사이징제가 적정 수준의 표면 에너지를 가져야 하며, 사이징제의 화학적 조성을 조정하여 에폭시 수지의 유동 특성과 계면전단강도가 모두 개선 가능함을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.372.1-372.1
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• 2016

Recently, there are a lot of diseases all around the world. Out of them, Atherosclerosis (AS) is the most common cause of stroke, cardiovascular mortality, and myocardial infarction. The macrophage-derived foam cell, which is formed by oxidized low-density lipoprotein (oxLDL), is the crucial marker for AS. In this study, we report a label-free capacitance imaging technique with multi-electrode array (MEA). The lipid-rich aorta arch lesions, which are derived from an apolipoprotein-E receptor-deficient (apoE-/-) mouse, exhibit higher capacitance than the lipid-free aorta arch, allowing the capacitance imaging of lipid region in atherosclerosis. To improve the contacts between MEA and tissue, polypyrrole(PPy)-coated multi walled carbon nanotubes (MWNTs) multi electrode array (PPy-MWNTs-MEA) was fabricated. Compared to TiN-MEA, PPy-MWNTs-MEA yielded lower contact impedance and better capacitance images. In addition, we have also developed a flexible MEA using single walled carbon nanotubes on a PET substrate. The lipid region could be discriminated in the capacitance images of the lipid-rich aorta arch lesions measured using flexible MEA, demonstrating a feasibility of in vivo applications.

• Advances in nano research
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• 제16권3호
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• pp.251-263
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• 2024

This article investigates the free vibration behavior of carbon nanotube reinforced composite (CNTRC) beams embedded using variational analytical methods and artificial neural networks (ANN). The material properties of layered functionally graded CNTRC (FG-CNTRC) beams are estimated using nonlocal parameters modified power-law with different types of CNT distributions through the thickness direction of the beam. Adopting Eringen's nonlocal elasticity theory to capture the small size effects, the nonlocal governing equations are derived and solved using the analytical method. And also, the problem was analyzed using the ANN method. The architecture of the proposed ANN model is 3-9-1. In the experiments, we used 112 different data to predict the natural frequency using ANN. Based on the nonlocal differential constitutive relations of Eringen, the equations of motion as well as the boundary conditions of the beam are derived using Hamilton's principle. The classical beam theory is used to formulate a governing equation for predicting the free vibration of laminated CNTRC beams. According to the experimental results, the prediction ability of the ANN model is very good and the natural frequency can be predicted in ANN without attempting any experiments.

• Structural Engineering and Mechanics
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• 제57권3호
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• pp.441-456
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• 2016

This work reports wave propagation in the nanocomposite cylinders that reinforced by straight single-walled carbon nanotubes based on a mesh-free method. Moving least square shape functions have been used for approximation of displacement field in weak form of motion equation. The straight carbon nanotubes (CNTs) are assumed to be oriented in specific or random directions or locally aggregated into some clusters. In this simulation, an axisymmetric model is used and also the volume fractions of the CNTs and clusters are assumed to be functionally graded along the thickness. So, material properties of the carbon nanotube reinforced composite cylinders are variable and estimated based on the Eshelby-Mori-Tanaka approach. The effects of orientation, aggregation and volume fractions of the functionally graded clusters and CNTs on dynamic behavior of nanocomposite cylinders are studied. This study results show that orientation and aggregation of CNTs have significant effects on the effective stiffness and dynamic behaviors.

• Structural Engineering and Mechanics
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• 제65권3호
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• pp.335-342
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• 2018

The transverse free vibration of chiral double-walled carbon nanotube (DWCNTs) embedded in elastic medium is modeled by the non-local elasticity theory and Euler Bernoulli beam model. The governing equations are derived and the solutions of frequency are obtained. According to this study, the vibrational mode number, the small-scale coefficient, the Winkler parameter and chirality of double-walled carbon nanotube on the frequency ratio (xN) of the (DWCNTs) are studied and discussed. The new features of the vibration behavior of (DWCNTs) embedded in an elastic medium and the present solutions can be used for the static and dynamic analyses of double-walled carbon nanotubes.