• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.345-348
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• 2004

In this study, an effect of fiber blending on material property of hybrid fiber reinforced concrete (HFRC) was evaluated. Also, optimized association and the mixing rate of fiber for HFRC was determined. Test result shows, in the case of mono fiber reinforced concrete, use of steel fiber in concrete caused increment in tensile and bending strength as the blended ratio increases, while use of carbon fiber and glass fiber caused increment in compressive strength. Use of hybrid fiber reinforcement in concrete caused a significant influence on its fracture behavior; consequently, caused increase by mixing rate of steel fiber and contributed by carbon fiber, glass fiber, celluloid fiber in reinforcement effect in order.

• 한국표면공학회지
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• 제29권5호
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• pp.424-429
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• 1996

Thin films of Ti-Ni alloy were formed by sputtering under various Ar gas pressures and r. f. powers to investigate the optimum sputtering conditions and to demonstrate their shape memory effect. The composition and structure of the films were examined by electron micro-probe analysis and scanning electron microscope. These films were annealed in order to crystallize them. The mechanical property of the annealed films was evaluated by a conventional bending test. The transformation tmeperatures were determined by differential scanning calorimetry. The shape memory behaviour was examined quantiatatively by changing in sample temperature under various constant loads. It was found that the Ar gas pressure had a critical effect on the mechanical property of the thin film,s although the r.f. power also affected it. The films formed at a high Ar gas pressure were too brittle to be bent successfully. However, the films formed at a low Ar gas pressur could be bent and their shape memory behavior was found to be comparable with that of bulk Ti-Ni alloys.

• 한국염색가공학회지
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• 제5권1호
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• pp.10-18
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• 1993

Epoxy compound was synthesized from bisphellol-A with epichlorophydrine. Epoxy compound and siloxane were emulsified conjugative one or another. The water repellency of silk fabrics was also highly improved by the treatment of epoxy-siloxane mixed emulsions containing stannic chloride and zirconium oxychloride. The maximum wrinkle recovery was obtained from the fabrics treated under the condition 2.5%-epoxy-siloxane emulsion at 16$0^{\circ}C$. The breaking elongation, the reflectance, the tensile strength and the bending properties of silk fabrics were not degraded severely by the treatment of epoxy-siloxane emulsion.

• Composites Research
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• 제15권1호
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• pp.61-69
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• 2002

This paper review research activities of some mechanical test methods thor advanced composites which have been conducted in Fukuda laboratory. Tokyo University of Science. The subjects are (1) innovation and development of compression bending test. (2) mechanical-property evaluation of soft-core sandwich beam, and (3) loop test to measure the strength of monofilaments.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.341-344
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• 2005

Recently, the application of Rapid Setting Cement has been gradually increased as an important construction. However, Rapid Setting Cement shows brittle failure. Therefore, in this study, tests are carried out using Rapid Setting Cement containing fiber in order to improve such a poor property. silica-cement ratio are varied. According to experimental results, Fiber reinforced Rapid -Setting Cement showed the high ductility and strain capacity regardless of silica-cement ratio. With 0.5 silica-cement ratio, a bending strength is the highest.

• 한국도로학회논문집
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• 제16권5호
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.

• 한국융합학회논문지
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• 제6권4호
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• pp.9-14
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• 2015

본 논문은 기타의 목 부분의 형상에 따라 가해지는 힘에 의한 휘어짐의 문제를 해결하기 위한 것으로, 기존의 기타를 보강하여 실제 사용 시, 하중에 취약한 부분을 파악하는 방법을 연구하였다. 본 연구에서는 실제 기타에 적용되는 목재의 물성치를 연구모델에 적용하고 모델링 한 후, 유한요소해석을 수행하였다. 본 논문의 연구를 통해 나온 결과를 사용하여 기존의 기타의 문제로 지적되어온 휨과 파손에 대한 기반자료를 얻을 수 있을 것으로 사료되며 이를 보강 할 수 있는 디자인을 연구하여 그 기타를 개선하고자 한다. 개선된 연구모델에 대한 결과를 토대로 실제 설계에 응용한다면 휨과 파손을 방지하여 내구성을 향상시킬 수 있으며 디자인 면에서의 융합기술로의 접목도 가능하며 미적인 감각을 나타낼 수 있다.

• 대한기계학회논문집A
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• 제40권3호
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• pp.267-273
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• 2016

본 연구에서는 부분 안정화 지르코니아(Z)와 자기치유능력을 부여하기 위하여 SiC와 $TiO_2$를 첨가한 5종류의 복합 지르코니아(ZS, ZST1, ZST2, ZST3, ZST5)를 소결하여, 기계적 특성과 열처리에 의한 균열 치유 가능성을 평가하였다. 6종류 지르코니아 세라믹스의 비커스 경도는 큰 차이가 없으며, 부분 안정화 지르코니아에 SiC 첨가(ZS)는 급격한 굽힘강도의 저하가 나타났지만, $TiO_2$의 첨가(ZST1, ZST2, ZST3, ZST5)는 강도가 향상하였다. 이는 SiC 및 $TiO_2$의 첨가의 따른 결정화의 영향이라 판단된다. 최고 굽힘 강도를 나타내는 균열 치유 조건에서 지르코니아 단상체는 비커스 균열이 남았으나, SiC가 첨가된 4종류는 비커스 균열이 관찰되지 않아 균열이 치유되었다.

• 감성과학
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• 제8권4호
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• pp.345-354
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• 2005

본 연구는 직물구조인자인 위사밀도와 직물의 조직을 변화시켜 시직한 면직물을 이용하여 역학특성 및 태의 변화를 KES-FB System을 이용하여 측정하였다. 그 결과 위사밀도가 증가할수록 굽힘특성 및 전단특성이 증가하는 것으로 나타났고, 위사밀도의 변화에 따른 역학특성치 중 굽힘 및 전단특성의 값은 평직이 높게 나타났으며, 인장특성, 압축특성 그리고 표면특성의 값은 조직 및 밀도에 크게 영향을 받지 않는 것으로 나타났다. 한편, 위사밀도 변화에 따른 의복착용성능 중 WC/T, MMD/SMD를 제외한 B/W 및 2HG/G, 2HB/B, 2HB/W, W/T, 그리고 WC/W는 위사밀도에 영향을 받는 것으로 나타났다. 위사방향의 직축은 굽힘특성, 전단특성, 압축회복도(RC), 표면거칠기(SMD), 태와 의복착용성능에 높은 상관을 보이는 것으로 나타났다. 그리고 Tightness는 굽힘특성, 전단특성, 압축특성 그리고 표면 마찰계수와 높은 상관을 보였고, 기본태 및 T.H.V., 의복착용성능에도 높은 상관이 있는 것으로 나타났다.

• Macromolecular Research
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• 제12권4호
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• pp.399-406
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• 2004

Glass-like carbon precursors shrink significantly during curing and carbonization, which leads to crack formation and bending. Cured furan resin powder and ethanol were added to furan resin to diminish the weight loss, to suppress the shrinkage and bending, and to readily release the gases evolved during polymerization and curing. Curing and carbonization were controlled by pressure and slow heating to avoid damage to the samples. The effect of the filler and ethanol on the fabrication process was examined by measuring the properties of the glass-like carbon, such as the specific gravity, bending strength, electrical resistivity, and microstructural change. The specific gravities of the filler-added glass-like carbons were higher than those of the ethanol-added samples because of the formation of macropores from the vaporization of ethanol during the curing and polymerization processes. Although the ethanol-added glass-like carbons exhibited lower bending strengths after carbonization than did the filler-added samples, the opposite result was observed after aging at 2,600$^{\circ}C$. We found that the macropores created from ethanol were contracted and removed upon heat treatment. The electrical resistivity of the glass-like carbon aged at 2,600$^{\circ}C$ was lower than those of the samples carbonized at 1,000$^{\circ}C$. We attribute this phenomenon to the fact that aging at high temperature led to well-developed microstructures, the removal of macropores, and the reduction of the surface area.