• Elastomers and Composites
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• 제33권4호
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• pp.281-289
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• 1998

4종류의 고무 즉, 천연고무(NR), styrene-butadiene copolymer(SBR), ethylene-propylene diene monomer(EPDM), brominated isobutylene-p-methyl-styrene copolymer(BIMS)의 영(Young) 탄성율을 비롯한 인장특성과 인열강도를 여러가지 가교도와 시험온도에서 측정하였다. 과가황(over-cure)의 영향을 조사하기 위해 과가교 고무컴파운드의 인장강도와 팽윤(swelling) 거동도 조사하였다. 모든 고무컴파운드에 대해 영 탄성율(E)은 가교도와 선형적인 비례관계를 보였다. EPDM이 가장 높은 기울기를 그리고 BIMS가 가장 낮은 기울기를 보였고, NR과 SBR은 이들 사이의 값을 나타내었다. 인열강도 Gc는 NR>BIMS>SBR>EPDM의 순으로 나타났다. 과가교에 따라 NR과 SBR의 가교도는 감소한 반면, BIMS는 오히려 증가하였고, EPDM은 거의 변하지 않았다.

• 대한정형외과스포츠의학회지
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• 제5권1호
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• pp.50-57
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• 2006

목적: 견관절 회전근 개 전층 파열시 관절경적 복원술 후 대결절에 부착되어진 회전근 개의 건이 상완골에 어느 정도의 비율로 건-골(tendon to bone)에 치유되는지에 대하여 알아보고자 하였다. 또한 저자들은 극상건 전층 파열된 례에서 관절경적 복원술 후의 기능적 평가를 시행하였다. 대상 및 방법: 연속적 인 30례의 극상건 전층 파열을 19례에서 one row of anchor를, 11례에서는 two rows of anchor를 사용해 관절경적 복원술을 시행하였다. 환자들의 연령은 51세부터 79세로 평균 63세였으며, 평균 추시 기간은 술후 12개월부터 28개월로 평균 16개월이었다. 술전과 마지막 추시에 주관적 및 객관적인 기능적인 평가를 위해 Constant, ASES와 HCLA score를 측정하였다. 해부학적인 건 치유를 확인하기 위해 30례 전례에서 술후 6개월에서 20개월, 평균 10개월째 자기 공명 관절 조영술(25례)이나 자기 공명 술(5례)을 시행하였다. 결과: 관절경적 복원술후 회전근 개의 대결절에 대한 완전 치유는 30례중 21례(70.0%)였고, 부분적인 파열은 3례(10%)였으며, 극상건이 전혀 치유되지 않아 대결절에 부착되지 못한 경우는 6례 (20%)였으나, 그 중 5례에서는 술후 남아있는 결손의 크기가 처음 술전 보다는 작았다. 객관적인 평가로 Constant score는 술전에 평균 $55.7{\pm}7.1$점에서 술후 마지막 추시 관찰시에 $77.7{\pm}9.7$점으로 향상되었고(p<0.001), ASES xcore는 술전 $39.2{\pm}7.4$점에서 $72.4{\pm}12.6$점으로 향상되었고(p<0.001), UCLA score는 술전 $17.9{\pm}2.2$점에서 $26.5{\pm}5.0$점으로 향상되었다(p<0.001). 견관절의 전방 거상시 근력 이 대결절에 치유된 례 $(7.1kgs{\pm}2.4)$에서 전혀 치유되지 않아 완전히 재 파열되었거나, 부분 파열을 보인 례 $(4.5kgs{\pm}1.0)$에서 보다 통계학적으로 의미 있는 향상을 보였다(p<0.05). 건 치유에 결정적인 영향을 미치는 인자는 환자의 나이였다. 65세 이상의 환자에서는 단지 41.7%만이 대결절에 극상건의 완전한 치유율을 보였다(p<0.05). 결론: 회전근 개 중 극상건 전층 파열된 례에서 관절경적 복원술 후 약 70%에서 완전한 치 유를 보였다. 술후 극상건의 부분 파열 및 재파열은 근력 저하와 직접적인 연관을 가졌다. 특히, 노령 환자에서의 회전근 개 상태가 술후 재파열과 밀접한 관련이 있다.

• Elastomers and Composites
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• 제34권1호
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• pp.31-44
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• 1999

4종류의 고무(NR, SBR, EPDM, BIMS)에 대해 완전가교 고무층과 부분가교 고무층간 계면 결합의 변화에 따른 계면 접착강도를 $30{\sim}120^{\circ}C$ 조건에서 조사하였고, 전자현미경을 이용하여 접착파단면을 조사하였다. 두 개의 완전가교 고무층간 계면에서는 물리적 결합이 계면 접착강도에 주도적인 역할을 하였고, 완전가교 고무층과 부분가교 고무층간 계면에는 물리적 결합과 화학적 결합이 공존하여 계면 접착강도에 영향을 미쳤다. 접착강도가 응집 인열강도와 유사한 수준으로 높을 때 NR은 "계면 노티인열" 형태를, EPDM은 "cross-hatched" 형태를 보였다.

• Journal of Welding and Joining
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• 제19권3호
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• pp.317-324
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• 2001

This study deals with high power Nd:YAG laser welding of thin steels for small pressure vessels. Full penetration welding at the overlap joint was performed so as to assure sufficient weld strength. Results showed that mid-depth weld size reduced drastically with increasing the travel speed. Position of focus had little effect on the bead formation even though short focal system was used. However, the shape factor and the bead width had closely related with the position of focus. Based on the microstructural inspection, acceptable weld was obtained when the overlap clearance was controlled up to 20% of the base metal thickness. In the case that the joint contained more clearance than the critical value, both the tensile shear strength and the tear strength were reduced. Results also demonstrated that shielding gases were proved to play a key role as far as the bead formation characteristics was taken into consideration. Blowing dry air through 5mm in diameter nozzle produced narrower bead cross-section than that of argon or nitrogen shielding.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 춘계학술발표논문집
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• pp.39-46
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• 2000

In pulp and papermaking process, enzymatic treatment of pulp fibres has been a topic of increasing interest in last decade. Lots of patents, papers and research reports were published on the application of enzymes in the fields of enzymatic bleaching, deinking, slime control, pitch control, waste water treatment and fibre modification. Cellulase and hemicellulase are the principal enzymes used for the modification of fibre property. This study was carried out for determinating the behaviors of enzyme to pulp fibres. A commercial enzyme, Denimax BT which is consisted with cellulase and hemicellulase, was treated to the kraft pulp produced from domestic hardwood mixtures. Results were mainly concentrated on the behaviors of freeness, drainability and fines content of fibres, and physical properties of paper with enzyme treatment. The freeness levels and dewatering ability were developed, and the fines contents were decreased. The creation of fines were controlled by the method of pre-enzyme treatment prior to fibre beating. The mechanical strength of paper, like tensile, burst, tear strength and folding endurance, were remarkably improved by the pre-enzyme treatment.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 추계학술발표논문집
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• pp.201-206
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• 2006

Embossing treated fruit bagging paper was prepared with newly designed embossing roll and mechanical properties of fruit bagging paper were evaluated. The embossing technology was developed. First of all, embossing roll was designed in Ginyong Embo(Co) for the embossing process of fruiting bag. The embossing treated fruit bagging paper was manufactured in Agro(Co) at plant scale. The mechanical properties of embossing paper was investigated and operation efficiency of bagging was tested at field. The properties of embossed paper was quit satisfied for fruiting bag for cultivation of apple and pears.

• Steel and Composite Structures
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• 제9권2호
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• pp.173-189
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• 2009

This paper presents a study on the behavior and design of bolted stainless steel plates under in-plane tension. Using an experimentally validated finite element (FE) program strength of stainless steel bolted plates under tension is examined with an emphasis on plate bearing mode of failure. A numerical parametric study was carried out which includes examining the behavior of stainless steel plate models with various proportions, bolt locations and in two different material grades. The models were designed to fail particularly in bolt tear-out and material piling-up modes. In the numerical simulation of the models, non-linear stress-strain material behavior of stainless steel was considered by using expressions which represent the full range of strains up to the ultimate tensile strain. Using the results of the parametric study, the effect of variations in bolt positions, such as end and edge distance and bolt pitch distance on bearing resistance of stainless steel bolted plates under in-plane tension has been investigated. Finally, the results obtained are critically examined using design estimations of the currently available international design guidance.

• 한국염색가공학회지
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• 제2권1호
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• pp.14-20
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• 1990

The cotton fabrics were treated with formaldehyde in the presence of zinc nitrate catalyst and urea. The effects of HCHO concentration, urea concentration, catalyst ratio, cure time and cure temperature on the physical properties of fabrics were studied. Cotton fabric finished with HCHO and urea had the lower tensile strength and tear strength than untreated one. These strength losses resulted from tighter oxymethylene crosslinks. The enhanced wrinkle recovery for fabric treated with formaldehyde in the presence of urea was indicative of the formation of urea-formaldehyde polymer. These experimental conditions were set up according to table of orthogonal arrays.

• 고무기술
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• 제5권2호
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• pp.94-103
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• 2004

The present work describes modification of dual phase filler by electron beam irradiation in presence of multifunctional acrylates like trimethylol propane triacrylate (TMPTA) or silane coupling agent like bis (3-triethoxysilylpropyltetrasulphide) and in-fluence of the modified fillers on the physical properties of styrene-butadiene rubber (SBR) vulcanizates. Modulus at 300 % elongation increases whereas the tensile strength decreases with increase in radiation dose for the dual phase filler loaded styrene-butadiene rubber vulcanizates (SBR). However, modulus and tensile strength significantly increase, which is more, pronounced at higher filler loadings for TMPTA modified dual phase filler loaded SBR. These changes in properties are explained by the equilibrium swelling data and Kraus plot interpreting the polymer-filler interaction. Electron beam modification of the filler results in a reduction of tan ${\delta}$ at $70^{\circ}C$, a parameter for rolling resistance and increase in tan ${\delta}$ at $0^{\circ}C$, a parameter for wet skid resistance of the SBR vulcanizates. Finally, the influence of modified fillers on the properties like abrasion resistance, tear strength and fatigue failure and the improvement in the properties have been explained in terms of polymer-filler interaction.

• 한국의류학회지
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• 제38권3호
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• pp.397-403
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• 2014

In this study, various types of Jumchi Hanji were made to develop shroud materials as a new use for Hanji. The properties of Hanji (basis weight, thickness, apparent density, bulk, tensile strength, wet tensile strength, elongation ratio, tear strength, bursting strength, and folding endurance) are measured. In all cases, Jumchi Hanji had a higher thickness, lower apparent density and higher bulk than Hanji because pores in the intervals of mulberry fiber are composed of bulk. So, it is considered to carry a value as a textile material. As for the results of the strength analysis of Jumchi Hanji, Jumchi technique enhances 25% of elongation ratio, which is regarded the most important role in textiles and 35% of bulk. Moreover, it was shown that it enhanced overall strength. In conclusion, it implies the possibility of applying it as a shroud material. Jumchi Hanji is thought to have enough potential to be developed as a material to carry the characteristics of Hanji in the textile market.