• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.694-697
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• 2015

We investigated the characterizations of carbon films fabricated by dual magnetron sputtering under various RF powers for the improvement of physical properties in carbon fiber (CF). All sputtered carbon films exhibited amorphous structure, regardless of RF powers, resulting in uniform and smooth surfaces. The hardness and elastic modulus are increased with the increase of RF power, and the adhesion and friction properties of carbon films were improved with the increase of RF power. In the results, The increase of RF power in the sputtering method improved tribological properties of the carbon films, and these attributes can be expected to improve the physical properties of the carbon fiber reinforcement plastics.

• Computers and Concrete
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• 제17권1호
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• pp.67-86
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• 2016

Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.367-370
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• 2003

Lightweight polymer concrete with steel fiber can be used for thin panel, high building and large span structures due to its may advantages such as its durability, low weight, control of crack propagation, high strength and toughness. This study experimented about steel fiber reinforcement of lightweight polymer concrete using synthetic lightweight aggregate. The test result shows that the maximum strain and elastic modulus are in the range of $0.012{\sim}0.014\;and\;50.2{\times}10^3{\sim}51.0{\times}10^3kgf/cm^2$, respectively. The flexural load-deflection curves after maximum load are shown in smoothly with increase of steel fiber content

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.71-74
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained fer two volume fractions.

• 소음진동
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• 제6권4호
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• pp.475-479
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• 1996

Recently, fiber optic hydrophone is a subject which has attracted as a underwater acoustic sensor. In this paper, a length of optical fiber is bonded to an end-capped hollow cylinder of some elastic material, e. g. aluminum and glass-pyres. The normalized sensitivity is derived according to the direction of polarization. Derived sensitivity equations are simulated for two different mandrel materials. The results are also compared to the McMahon's results which calculated for an average Pockel coefficient. Based on the numerical simulation normalized sensitivity is propotional to the inner to outer diameter ratio.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.37-41
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• 2003

In this study the mechanical behaviors of fiber metal laminates (FML) such as ARALL, GLARE and CARE which are recently developed as new structural materials and known to have excellent fatigue resistant characteristics while with relatively low densities compared to the conventional aluminum materials, are considered through the classical lamination theory. The mechanical properties such as elastic moduli, thermal expansion coefficients and hygro-thermally induced residual stresses in the fiber metal laminates are obtained and compared each other. Also load carrying mechanism between metal sheets and composite layers in the FML are considered.

• 한국산업융합학회 논문집
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• 제14권1호
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• pp.1-7
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• 2011

Basalt originates from volcanic magma and flood volcanoes, a very hot fluid or semifluid material under the earth's crust, solidified in the open air. Basalt is a common term used for a variety of volcanic rocks, which are gray, dark in colour, formed from the molten lava after solidification. Recently, attention has been devoted to continuous basalt fibers (CBF) whose primary advantage consists in their low cost, good resistance to acids and solvents, and good thermal stability. In order to investigate reinforcement effect, this paper did FEM analysis with shell element. The result were as follows; BCF deck plate did elastic behavior to 450 kN, reinforcement effect of basalt fiber (BF) was less. But BCF's perpendicular deflection occurred little about 23 mm comparing with RC deck plate in load 627 kN. Stiffness was very improved by basalt fiber reinforcement.

• 한국농공학회지
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• 제45권2호
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• pp.58-67
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• 2003

Over the last decade fiber-reinforced polymer (FRP) reinforcement consisting of glass, carbon, or aramid fibers embedded in a resin such as vinyl ester, epoxy, or polyester has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. But reinforcing rebar for concrete made of FRP rebar has linear elastic behavior up to tensile failure. For safety a certain plastic strain and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. The same should be required for FRP rebar. Thus, the main object of this study was to develop new type of hybrid FRP rebar Also, this study was evaluated to the mechanical properties of Hybrid FRP rebar. The Manufacture of the hybrid FRP rebar was achieved by pultrusion, and braiding and filament winding techniques. Tensile and interlaminar shear test results of Hybrid FRP rebar can provide its excellent tensile strength-strain behavior and interlaminar stress-strain behavior.

• KCI Concrete Journal
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• 제14권2호
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• pp.61-68
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• 2002

An experimental investigation on the flexural fatigue behavior of a RC bridge slab retrofitted with Carbon Fiber Sheet (CFS) is presented. The test slab was almost identical to the slab of a highway viaduct in terms of the amount of reinforcement, quality of concrete and thickness of the slab, which was 18cm. Repeated load corresponding to 3.0, 4.5 or 6.0 times of the design load was applied to the test slab. Normal type and high-elastic modulus type of CFS were used for strengthening. The test slabs were loaded in dry or wet condition. Two different types of an-choring system were adapted. Some of the test slabs were damaged by the repeated load and retrofitted by CFS, then loaded again to see the improvement of the fatigue life. Infrared Thermography was also performed to investigate the debonding condition of CFS. From the test results, Carbon Fiber Sheet can be applied to the RC bridge slabs as a feasible retrofitting material.

• 한국식품영양과학회지
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• 제16권3호
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• pp.11-20
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• 1987

우육(牛肉) 조리시(調理時) 첨가(添加)되는 향신료(香辛料) 등이 우육(牛肉)의 연화(軟化)에 미치는 영향(影響)을 알아보기 위하여 향신료(香辛料) 자체(自體)의 단백질(蛋白質) 가수분해능(加水分解能)의 유무(有無)와 이에 따른 연화효과(軟化效果)를 연육소(軟肉素) 및 연육기(軟肉器)에 의한 연육효과(軟化效果)와 비교(比較) 검토(檢討)하였다. 1. Casein을 기질(基質)로 하여 향신료(香辛料)의 단백질(蛋白質) 분해효소능(分解酵素能)의 유무(有無)를 실험(實驗)한 결과(結果), 모든 시료(試料)에서 단백질분해효소능(蛋白質分解酵素能)이 확인(確認)되었으며 각(各) 시료(試料)의 단백질(蛋白質) 분해정도(分解精度)는 마늘, 무우, 생강 그리고 양파의 순(順)으로 컸다. 2. 조직학적(組織學的) 특성검사(特性檢査)에서 연육소처리(軟肉素處理)를 한 조직(組織)은 전반적(全般的)으로 collagen 및 elastic fiber, 근계육(筋繼維) 등이 분해(分解)되는 정도(程度)가 현저(顯著)하였으며, 연육기처리(軟肉器處理) 조직(組織)은 collagen 및 elastic fiber, 근계육(筋繼維) 등이 절단(切斷)되어 조직(組織)이 붕괴(崩壞)되었다. 또한 향신료(香辛料)를 처리(處理_한 조직(組織)도 단백질(蛋白質) 가수분해효소능(加水分酵素能)에 의해 collagen, elastic fiber 및 근계육(筋繼維)가 부분적(部分的)으로 분해(分解)되었다. 3. 처리육(處理肉)의 유연성(柔軟性)에 대한 관능검사(官能檢査)의 결과(結果), F-value가 11 27로 4가지 시료(試料)사이에 1% 수준에서 유의성(有意性)이 인정(認定)되었으며, 시료간(試料間) 유의성(有意性)의 차이(差異)에 있어서 향신료처리(香卒料處理) 쇠고기는 5% 수준(水準)에서 처리(處理)하지 않은 쇠고기와의 간(間)에 유의성(有意性)이 인정(認定)되었다.