• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
• /
• pp.384-386
• /
• 2005

Initial oxide layer on the butt surface fragments during friction stir welding (FSW) and then often remains as a faint zigzag-line pattern on the cross section. When remnant of the oxide layer often adversely affects the mechanical properties in the weld, it is called as 'kissing-bond'. The present study systematically examines effect of oxide array on bend property in the root of friction stir (FS) welded Al alloy 1050 by transmission electron microscopy (TEM), and then clarifies identity of the kissing-bond.

• 소성∙가공
• /
• 제6권2호
• /
• pp.136-144
• /
• 1997

(Ag-10%Ni)/Cu clad metals for electric contact switch were fabricated by cold-roll bonding process. 2 or 3 passes of cold-rolling was carried out for each process to investigate the effect of the rolling passes on the bonding property. The effect of the annealing temperature of copper before the cold-roll bonding on the bond strength was also studied. The specimen bonded with copper annealed below 30$0^{\circ}C$ before roll bonding showed good bond strength. This is because high stored energy in copper promoted the short range diffusion and the grain refinement of copper by the static recrystallization increased the degree of the interfacial coherency. The maximum peel strength of clad metals bonded with Cu annealed below 30$0^{\circ}C$ was 120N.

• 대한치과기공학회지
• /
• 제37권4호
• /
• pp.219-227
• /
• 2015

Purpose: The purpose of this study was to evaluate the effect of the chemical surface treatment on the flexural bond strength of heat curing denture base resin and reliners. Methods: Denture base resin surface was treated with MMA 95% and TEGDMA 5%, MMA 95% and silane coupling agent 5%, heat curing resin monomer. After denture reliners were injected, flexural bond strength was measured. Results: The repair resin of Vertex SC was higher than Lang, hard reliner of Kooliner was higher than Rebase. Soft reliner of Dura base and Coe-soft showed differently according to the surface treatment. The all chemical treatment groups on Vertex SC were significantly higher than control(p<0.05). In Lang group, 5% MPS treated group showed significantly higher flexural bond strength than others(p<0.05). In Kooliner group, all chemical treatment groups showed significantly higher than control(p<0.05). In Rebase group, the 5% MPS and the monomer denture base resin treated groups showed significantly higher than others(p<0.05). In Dura base group, 5% MPS treated group showed significantly higher flexural bond strength than others(p<0.05). In Coe-soft group, all treated groups were significantly higher than control group(p<0.05). Conclusion: TEGDMA, MPS, and the monomer of heat-cured denture base resin were effective to improve the bond strengths between denture base and denture relining materials. Especially, 5% MPS expected to strengthen effectively the bonding property of denture base and denture reliners within the results of this study.

• 대한치과보철학회지
• /
• 제38권5호
• /
• pp.650-658
• /
• 2000

This study was investigated to compare the bond strength of polysulfide adhesive between tray resin and border molding materials and to evaluate the effect of saliva contamination on them. We made the 135 resin tray secimens with a dimension of $1{\times}1{\times}1cm$ and divided them into 3 groups by the materials 1) Quicky group, 2) Compound group, and 3) Impregum group Each group was subdivided by saliva contimination. Group S1 : applied adhesive without saliva contamination Group S2 : applied adhesive after drying 15seconds after saliva contamination Group S3 : applied adhesive no after saliva contamination. Tensile tests were performed with a Universal Load testing machine. Results showed Impregum group significantly higher bond strength than Quicky group, but there was no significant difference in adhesive bond strength between Compound group and Quicky group in experimental group by materials In experimental group by saliva contamination, S1 group is significantly higher bond strength than S2 group and S2 group is significantly higher bond strength than S3 group in Quicky group and S1, S2 group is significantly higher bond strength than S3 group in Compound group and Impregum group. Impression compound and Impregum F which are usually used as an individual tray border mold-ing material can be said to be satisfied in adhesive bond strength to polysulfide impression materials. After try-in and clinical adjustment are performed, a custom tray should be properly rinsed and air dried before tray adhesive was placed.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
• /
• pp.245-250
• /
• 1998

The Elastic modulus depends on the elastic property of composition materials, the gravity of aggregate, the bond strength of binder, the usage and quantity of admixture, curing and measuring method, etc. Accordingly, the aim of this study, by manufacturing concrete of practical high strength range(600~ 1000kg/$\textrm{cm}^2$) with the specific cement and mineral admixtures, is to compare elastic modulus with the existing equations and also to estimate elastic property of use materials. As a result, it could be confirmed that the existing equations which were proposed by the ACI 363, CEB-FIP Code, and New-RC have a tendency to the overestimation in general. However, it could be confirmed that the KCI-96 and Norwegian NS 3473 equations are closed to measuring results, and that the elastic modulus property have a different tendency due to types of cements.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
• /
• pp.185-186
• /
• 2008

Use of the carbon nanotube is superior to general powder state materials of dispersion property. Because its ratio of diameter and length(aspect ratio) is very large, it has been known as a type of ideal nano-reinforcement composite. It used solution mixing method for specimen fabrication. To research dispersion property, we used FE-SEM(Field Emission Scanning Electron Microscope) and AFM(Atomic Force Microscope). As a result, this tendency confirms new conductivity network in which the carbon nanotube between carbon black constitute molecules shows a bond by similar constructive property.

• 한국건설순환자원학회논문집
• /
• 제3권1호
• /
• pp.84-89
• /
• 2015

현무암섬유는 높은 인장강도와 콘크리트와 유사한 밀도를 갖기 때문에 콘크리트 보강 섬유로서 장점을 갖고 있다. 이 연구에서는 현무암섬유의 부착 특성과 섬유 배향각에 따른 현무암섬유의 인장 강도 특성을 조사하였다. 이를 위하여 현무암섬유와 폴리비닐알코올섬유에 대한 섬유 인발 실험을 수행하였고, 현무암, 폴리비닐알코올, 폴리에틸렌섬유에 대하여 섬유 배향각에 따른 인장 강도를 측정하였다. 실험 결과 현무암섬유의 화학적 부착, 마찰 부착, 미끌림 경화 계수는 폴리비닐알코올섬유와 비교하여 각각 1.88, 1.03, 0.24배로 나타났다. 현무암섬유의 배향각에 따른 강도 감소 계수는 폴리비닐알코올섬유의 9배, 폴리에틸렌섬유의 3배로 나타났다.

• 한국결정성장학회지
• /
• 제34권3호
• /
• pp.79-85
• /
• 2024

고압 균질기를 이용하여 면 셀룰로오스 원료로부터 직접 셀룰로오스 나노결정을 추출하고 이에 대한 결정 구조 및 화학적 결합 상태에 대한 연구를 수행하였다. 형성된 셀룰로오스 나노결정은 나노와이어 형태의 구조적 특성을 가지며, 조밀한 구조의 메쉬 형태로 분포하였다. X-ray diffraction (XRD) 분석을 통해 관찰된 Bragg 결정면의 면간거리 계산을 통해 고압 균질기로부터 추출된 셀룰로오스 나노결정이 셀룰로오스 Iβ 하부 다형체인 monoclinc 결정구조를 갖음을 확인하였다. 셀룰로오스 나노결정에 포함된 비정질 영역을 정량적으로 평가하기 위한 Solid-state nuclear magnetic resonance(NMR) 분석 결과 셀룰로오스 나노결정의 결정화도 지수는 5 3.06 %로 계산되었다. 형성된 셀룰로오스 나노결정 표면의 O/C ratio는 0.82로 계산되었으며, C-C 결합 혹은 C-H 결합, C-O 결합, O-C-O 결합 혹은 C=O 결합, O-C=O 결합의 화학적 결합이 셀룰로오스 나노결정 표면의 주요 화학적 상태임을 알 수 있었다.

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2002년도 추계학술대회
• /
• pp.669-669
• /
• 2002

No Abstract, See Full Text

• 한국콘텐츠학회논문지
• /
• 제15권2호
• /
• pp.344-351
• /
• 2015

본 논문은 치과에서 많이 사용되고 있는 silane coupling agent로 표면 처리한 의치상 레진과 자가중합 레진 간의 전단 결합력에 미치는 영향에 대해 알아보고자 하였다. 의치상 레진에 silane coupling agent 농도별 표면 처리 후 자가중합레진을 주입하여 전단결합강도를 측정하였다. Silane coupling agent(MPS)의 농도별 표면 처리에 따른 의치상 레진과 자가중합레진 간의 전단결합강도에서는 Vertex self curing resin에서 5%, 7%에서 유의적으로 높게 나타났고(P<0.05), Kooliner에서는 5%에서 유의적으로 가장 높게 나타났다(P<0.05). 따라서 의치상 레진과 자가중합레진 사이에 MPS 5%를 이용한 표면처리가 전단결합강도에 효과적으로 영향을 미치는 것이라 사료된다.