• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.273-276
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• 2005

Polymer-modified mortar was developed for improving the performance of modified mortar which is mixed with polymer, and it is used for protecting and repairing materials of building because of their excellent performance to improve characteristics which are compressive strength, flexural strength, and adhesive strength. However, the performances of the polymer-modified mortars are highly affected by materials, which are polymer, mortar, and aggregates, and conditions which are curing environment and testing method. Furthermore, dry curing method after hydrated curing has been recommended to make strong polymer film for the best curing method to make excellent characteristics. In this report, We investigated the co-relation between curing methods and the characteristics, which are compressive strength, flexural strength, and adhesive strength for the polymer-modified mortars that are used in the domestic area.

• 전기학회논문지
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• 제56권11호
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• pp.1955-1961
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• 2007

In this paper, we propose the mathematical model for the vehicle system including running characteristics. The well defined model for a system is necessary to study and to enhance system performance. To model the dynamic properties of vehicle system, we have considered two fundamental parts. The first part is the motion equations for vehicle based on Newton's second law. The second part is the torque dynamics of the traction motor. These parts are affected by outer conditions such as adhesive coefficient, running resistance and gradient resistance. The each parts are presented by the numerical formula. To test the driving characteristics of the developed model, we performed the simulations by dynamic system simulation software, "SIMULINK" and the results are given for several conditions.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.232-236
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• 2004

The fracture characteristics of unidirectional composite single-lap bonded joints were investigated experimentally and numerically. The effects of bonding method, surface roughness, bondline thickness and the existence of fillet on the failure characteristics and strength of bonded single-lap joints were evaluated experimentally. The failure process, failure mode and the behavior of load-displacement curve was apparently different according to bonding method. The failure load of the specimen co-cured without adhesive was definitely superior to other types of specimens but the specimens co-cured with adhesive film had a less strength than secondary bonded specimens. In the secondary bonded specimens, the lower value of surface roughness and existence of fillet improved the strength of specimens. The strain energy release rates calculated by geometric nonlinear finite element analyses and Virtual Crack Closure Technique for the secondary bonded specimens considering the three types of initial cracks - comer crack, edge crack and delamination crack - were consistent with the test results.

• 보존과학회지
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• 제35권6호
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• pp.681-688
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• 2019

본 연구에서는 목공예품에 사용되는 천연 및 합성 접착제의 특성을 평가하고, 온습도 변화에 따른 접착제와 목재의 열화 양상을 비교하였다. 아교 1종, 폴리초산비닐계 접착제 3종, 에폭시계 접착제 1종와 느티나무 목재를 선정하여 물리적, 화학적 특성평가와 내후성, 건조속도 평가를 진행하였다. 접착제 특성평가를 통해 아교와 폴리초산비닐계 1종의 접착강도가 각각 6.54 N/㎟과 7.01 N/㎟으로 나타났으며, 아교는 pH 7.03, 폴리초산비닐계 접착제는 pH 3.32~3.59으로 접착제로써 사용가능한 범위인 것으로 확인되었다. 내후성 실험결과 에폭시계 접착제는 열화 후 접착강도 감소폭이 가장 높았다. 접착제에 대한 가역성 실험을 통해 에폭시를 제외하고 수용성용매인 NaOH에서 가역성이 높은 것으로 나왔으나 처리 시 목재에 변색이 나타날 수 있으므로 사용 시 주의가 필요하다.

• Journal of the Korean Wood Science and Technology
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• 제48권3호
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• pp.303-314
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• 2020

Gambir is a non-wood forest product with a potential of being used as wood adhesive, due to about 33% catechin in it. Meanwhile, catechins and sucrose have not been studied as adhesives. Therefore, basic characteristics of gambir-sucrose adhesives were investigated. In this research, adhesives were prepared by dissolving gambir and sucrose in distilled water, at different blending ratios of the gambir/sucrose such as 100/0, 75/25, 50/50, and 25/75 wt%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was employed to determine the gambir chemical compositions, and Fourier transform-infrared (FTIR) spectroscopy was carried out to identify chemical bonds. Particleboards with a target density of 0.8 g/㎤ were then manufactured by hot-pressing for 10 min at 200℃. The internal bond (IB) strength of particleboard was subsequently measured. Based on the GC-MS analysis, 31.11% of catechin was identified. In addition, the viscosity, density, solid content, and gelation time of the adhesives, and insoluble matter content (IMC) in boiling water were 7.30~33.24 mPa.s, 1.2~1.3 g/㎤, 25.56~28.44%, 73~420 min, and 29.75~62.10%, respectively. Adding sucrose to the adhesive was observed to raise the IMC from 49.05 to 62.10%, at 180℃ and 200℃. FT-IR analysis showed that the gambir absorption peaks occurred at approximately 1620 cm^-1, assigned to the C=O stretching of 5-hydroxymethylfurfural, which tended to increase with the addition of sucrose. The reaction between gambir and sucrose was observed in the form of the dimethylene ether bridge. The 25/75 wt% gambir-sucrose adhesives and 200℃ hot-pressed temperature resulted in the highest IB strength (0.89 MPa), and met the requirement of JIS A5908-2003 type 18. Consequently, the gambir-sucrose adhesive could be used as a particleboard adhesive.

• 보존과학회지
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• 제27권3호
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• pp.261-268
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• 2011

본 연구는 문헌연구를 바탕으로 하여 전통적인 방법으로 풀을 조제하여 배접하는 경우 첨가제가 풀의 성질 및 접착특성에 미치는 영향을 고찰한 결과이다. 본 연구는 향후 회화문화재의 보존처리용 천연접착제 개발을 위한 기초자료로 제시하고자 한다. 따라서 본 연구에서는 접착제에 첨가제가 미치는 영향을 검토하기 위하여 임원경제지(林園經濟志), 거가필용사류전집(居家必用事類全集), 다능비사(多能鄙事), 죽여산방잡부(竹嶼山房雜部)에서 공통적으로 사용되고 있는 백반과 황랍을, 장황지(裝潢志)와 제민요술(濟民要術)에서 공통적으로 사용되고 있는 석회를 첨가제로 사용하여 그 특성 즉, 점도, pH, 유연성, 박리강도, 항균성, 방미성, 보존성 등을 측정하여 고찰하였다. 그 결과 첨가제 고유의 특성이 풀의 특성에 큰 영향을 미치는 것을 알 수 있었다. 백반은 유연성을 증가시켰으나, 점도, 접착강도, pH는 감소시켰으며, 황랍은 유연성, 점도, 접착강도, pH를 모두 감소시켰으며, 석회는 유연성, 점도, pH, 접착강도를 모두 증가시키는 경향을 나타내었다.

• 폴리머
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• 제37권5호
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• pp.625-631
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• 2013

점막접착 기능은 인체의 다양한 장기에 적용되는 의료용 접착제에 요구되는 중요한 특성이며, 점막접착 기능을 갖는 고분자를 개발하기 위하여 많은 연구가 이루어지고 있다. 최근 많은 연구자들이 생체모방 기술을 통한 점막접착형 고분자를 개발하고 있고, 그 중 해양 부착 생물인 홍합의 접착 기능 및 특성이 접착제 연구의 주요 대상이 되어왔다. 본 연구에서는 홍합 접착 물질 속에 과량 존재해 표면 접착 기능을 발현하는 카테콜 구조가 도입된 생체모방형 고분자를 합성하였고, 핵자기공명분광법 및 젤투과크로마토그래피를 사용하여 분석하였다. In vitro 상에서 돼지의 소장점막하조직 sheet를 준비하여 전단 시편을 제작하고 점막접착력을 측정하였다. 점막접착형 고분자는 현재 상업적으로 사용되고 있는 대조군인 피브린글루와 비교할 때 월등한 접착력을 보였다. 또한, 다양한 인자를 변화시키며 최적의 점막접착력을 나타내는 조건을 확립하였다. 이러한 결과들을 토대로 우수한 점막접착형 특성을 나타내는 고분자를 개발하였고 다양한 임상적용 및 의료용 기기에 도입가능한 소재의 기초연구를 수행하였다고 사료된다.

• 한국가구학회지
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• 제14권2호
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• pp.21-29
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• 2003

This study was carried out to investigate characteristics of plywood overlaid with softwood veneers densified by resin impregnation and compression. The resin impregnability of Korean pine veneer under atmospheric pressure soaking was greater than that of larch, and impregnability of melamine resin was slightly greater than phenolic resin. It was suggested that resin impregnation ratio was affected by density and thickness of veneer. The largest melamine resin impregnation ratio of 50.7% was obtained with 1.26mm thick Korean pine veneer, and the lowest phenolic resin impregnation ratio of 11.7% with 3.41mm thick larch veneer. Therefore, it was suggested that the vacuum-pres sure-soak treatment is required at thick larch veneer. In densifying resin-impregnated veneers, densification ratio from 13.4 to 31.2% was obtained by high pressure from 15.6 to $20.8kgf/cm^2$. Impregnation of melamine resin also showed relatively greater at densification than that of phenolic resin. So it showed the degree of densification of about 20% or greater. It was seemed that adhesive bonding strength of plywood(base panel) which was directly pressed and overlaid with resin-impregnated veneer was affected by resin tackiness after resin impregnation followed by semi-drying. In laboratory scale, melamine resin impregnation was more favorable for the development of adhesive bonding strength owing to moisture control.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1151-1154
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• 2005

The size effects for adhesive and frictional characteristics were studied. The specimen was Mica and the AFM tips were SiO2. The radii of SiO2 tip were 280, 380, 930, and 2230 nm on which tribological tests had never been performed. It was found that the adhesive forces and the frictional coefficients increased non-linearly with tip radius. Compared with previous studies at nanoscale and microscale, the results showed behaviors bridging each previous result. It could be said that these results were clues to explain the material behaviors between nanoscale and microscale both in adhesion and friction.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.543-546
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• 2005

The development and maintenance of a sound bond are an essential requirements of concrete repair and replacement. The bond property of a bonded overlay to its substrate concrete during the lifetime is one of the most important performance requirements which should be quantified This study was performed to investigate the characteristics of adhesive strength for overlay concrete. Three different removal methods of deteriorated concrete such as chip-patch, mill-patch and water-jet were varied in this study. According to the adhesive strength of pull- off test, case III using water-jet was measured $2\~3$ times higher than that of chip-patch or mill-patch.