• 한국작물학회지
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• 제27권1호
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• pp.1-10
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• 1982

주요 수도품종들의 탈립성 정도와 곡립의 인장강도와 탈립성 및 수확작업시 포장손실과의 관계를 밝히므로서 탈립성에 관한 품종개량 및 포장손실의 최소화에 도움을 주고자 본 연구를 수행하였다. 11개 품종을 공시 공시했으며 출수 후 35일부터 63일까지의 기간에 1주일 간격으로 품종 및 수확기 별로 임의 추출한 10이삭 200립씩에 대한 곡립의 인장강도, 탈립정도 및 수분함량을 측정했으며, 탈립정도는 이삭을 수확직후 1.5m 지상에서 콘크리트바닥에 낙하시켰을 때 탈립되는 곡립수의 전곡립수에 대한 비율이었다. 또한 포장손실과 곡립의 인장강도와의 관계는 농가포장에서 2품종을 선정하여 출수 후 40일부터 1주일 간격으로 3-4회 binder harvester를 실제 사용하여 포장에 탈립된 량을 측정하고 이를 같은 재료에 대해 측정한 곡립의 인장강도와 관계를 지었으며 3반복하였다. 그 주요결과는 다음과 같이 요약된다. 1. 공시품종들의 평균 곡립인장강도는 90g(밀양 2003) 정도부터 250g(진흥) 정도까지의 범위에서 품종 및 수확기에 따라 차이가 있었으며, 그 표준편차는 30-60g 정도이었는데 곡립의 평균 인장강도가 큰 품종일수록 편차가 컸다. 2. 낙하검정에 의한 곡립의 탈립정도는 밀양2003 20-30%, 수원 29004 3-16%, 한강찰 13-15%, 이리 348호 1-21%, 금강 및 태백 1% 정도로서 수확기에 따라 다소간 차이를 보였다. 3. 낙하검정에서 탈립하기 시작하는 평균 인장강도는 180g이었고, 공시이삭들의 곡립들 중 인장강도가 98g 이상인 것들은 탈립하지 않았으며 인장강도가 10g 저하하면 탈립율은 3-5% 증가했다. 4. 낙동벼와 이리 348호는 수확기가 늦어지면 곡립의 인장강도가 작아지었지만 그밖의 품종들에서는 반대로 인장강도가 다소간 커지거나 별로 변화하지 않았으며, 탈립율도 이리 348호를 제외하면 수확기의 영향을 크게 받지 않았고, 곡립의 인장강도는 수분함량과 대체로 역상관관계를 보였다. 5. 곡립의 평균 인장강도와 binder 수확시의 포장손실량과는 부의 상관이 있었으며, binder 수확시 포장손실이 일어나지 않게 되는 한계 평균인장강도는 174g이었으며 그 이하에서 평균인장강도가 10g 저하되면 포장손실은 ha당 40kg 정도 증가하였다. 6. 현재 품종들의 탈립성 분류기준으로 사용되고 있는 평균인장강도는 그 분산이 변이가 크고, 환경의 영향을 많이 받으며 이삭의 곡립들 중 수확작업시 실제로 탈립이 잘 되는 곡립은 인장강도가 98g이하이었으므로 품종의 탈립성 판정 및 포장손실의 추정을 위해서는 표본중 인장강도가 100g 이하인 곡립들의 전곡립수에 대한 비율을 기준으로 할 것을 제의한다.

• 한국생활과학회지
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• 제9권4호
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• pp.483-489
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• 2000

The purpose of this study is to verify the effect of cellulase treatment on crease resistance of cotton. Cotton fabrics was treated with cellulase under different concentration at $50^{\circ}C$ for 40 min. Also to compare the effect of DMDHEU treatment, DMDHEU treatment was conducted before and after cellulase treatment, also with cellulase. Weight loss, crease resistance and tentile strength of each samples were measured and compared. Maximum weight loss showed at 1g/l con. with 40 min. treatment. Cellulase enzyme treatment was more effective than DMDHEU in the crease resistance and tensile strength. Crease resistant of cotton which treated under different condition with cellulase and DMDHEU showed in the order of cellulase+DMDHEU> cellulase> DMDHEU treatment. Also, tensile strength showed in the order of cellulase> cellulase+DMDHEU> DMDHEU. Among those treatment conditions, condition which treated with cellulase considered more effective to increase crease resistance while keeping tensile strength too.

• 대한가정학회지
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• 제37권12호
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• pp.169-177
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• 1999

This study has examined weight loss rates of Iyoceu, lyocell/cotton, cotton that were treated with cellulase under different concentration, time, temperature and pH. and compared physical properties changes of tensile strength, drape, moisture absorbency, shrinkage and dyeability. The notable results are summarized as follows: Lyocell was in need of pretreatment by NaOH in the side of weight loss, tensile strength and dyeability. Weight loss rates of cellulose fabrics by cellulase treatment were in the order of cotton > lyocell/cotton > lyocell at the same conditions. In case of lyocell and lyocell/cotton, weight loss rates showed up lower than cotton, while strength retention decreased, drape and strength flexibility were highly improved after cellulase treatment.

• 복식문화연구
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• 제21권6호
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• pp.967-973
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• 2013

During high speed sewing, the needle thread is exposed to dynamic loading, short strike loading, inertia forces, friction, rubbing, force of check spring, bending, pressure, friction, impact, shock and thermal influence. The dynamic thread loading/tension alters throughout the stitch formation cycle and along its passage through the machine. The greatest tensile force occurs at the moment of stitch stretching, when the take up lever pulls for required thread length through the tension regulator. These stresses act on the thread repeatedly and the thread passes 50-80 times through the fabric, the needle eye and the bobbin case mechanism, before getting incorporated into the seam, which result in upto 40% loss in tensile strength of the sewing thread. This damage in the sewing thread adversely affects its processing and functional performance. In this paper, the contribution of dynamic loading, passage through needle and fabric, and bobbin thread interaction in the loss in tensile properties has been studied. It is observed that the loss in tensile properties occurs mainly due to the bobbin thread interaction. Dynamic loading due to the action of take up lever also causes substantial loss in tenacity and breaking elongation of cotton threads.

• 폴리머
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• 제33권6호
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• pp.581-587
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• 2009

PLA와 PEG를 사용하여 용융블렌드 방법으로 PLA/PEG 블렌드 섬유를 제조한 후 in vitro 환경조건인 pH7.4, 온도 $37\;^{\circ}C$의 완충용액에서 1~8주 동안 가수분해한 다음 무게감량률 및 인장강도 등에 미치는 영향을 검토하였다. 가수분해 시간이 1주에서 8주까지 증가함에 따라 블렌드 시간은 10~30분으로, PEG 함량은 5~30 wt%로 증가할수록 PLA/PEG 블렌드 섬유의 무게감량률은 증가하는 경향이, 인장강도 및 인장탄성률은 감소하는 경향이 현저하게 나타남을 확인하였다. 결론적으로 가수분해 시간 2주까지는 PLA/PEG 블렌드 섬유의 무게 감량률은 약 0.9% 이내이고 강도유지율은 약 90% 이상을 나타냄으로써 임계상처치유기간 중 양호한 강도가 유지될 수 있음을 확인하였다.

• Fibers and Polymers
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• 제6권1호
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• pp.13-18
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• 2005

PLA/LPCL/HPCL blend fibers composed of poly (lactic acid) (PLA), low molecular weight poly ($\varepsilon$-caprolactone) (LPCL), and high molecular weight poly ($\varepsilon$-caprolactone) (HPCL) were prepared by melt blending and spinning for bioab­sorbable filament sutures. The effects of blending time and blend composition on the X-ray diffraction patterns and tensile properties of PLA/LPCL/HPCL blend fibers were characterized by WAXD and UTM. In addition, the effect of in vitro degra­dation on the weight loss and tensile properties of the blend fibers hydrolyzed during immersion in a phosphate buffer solu­tion at pH 7.4 and 37$^{\circ}C$ for 1-8 weeks was investigated. The peak intensities of PLA/LPCL/HPCL blend fibers in X-ray diffraction patterns decreased with an increase of blending time and LPCL contents in the blend fibers. The weight loss of PLA/LPCL/HPCL blend fibers increased with an increase of blending time, LPCL contents, and hydrolysis time while the tensile strength and modulus of the blend fibers decreased. The tensile strength and modulus of the blend fibers were also found to be increased with an increase of HPCL contents in the blend fibers. The optimum conditions to prepare PLA/LPCL/HPCL blend fibers for bioabsorbable sutures are LPCL contents of $5 wt\%, HPCL contents of $35 wt\%, and blending time of 30 min. The strength retention of the PLA/LPCL/HPCL blend fiber prepared under optimum conditions was about $93.5\% even at hydrolysis time of 2 weeks.

• E2M - 전기 전자와 첨단 소재
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• 제9권10호
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• pp.1033-1039
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• 1996

Electrical and mechanical properties of polymer sheet at cryogenic temperature have been investigated. Tensile stress(and strain at break) in liquid nitrogen(77K) of 79.7MPa(l.2%) and 117.4MPa(2.05%) are evaluated for films of Polypropylene (PP) and Kapton, respectively. Dielectric loss tangent(tan .delta.) of PP and Kapton films is almost independent of the frequency and tensile stress. Also, field strength of PP film at 77K decreases with increasing the tensile stress.

• 자동차안전학회지
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• 제7권3호
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• pp.19-24
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• 2015

Brake pads are a component of disc brake system of automobile and consist of steel backing plates and friction material facing the disk brake rotor. Due to the repeated sliding forces and torque in vehicle braking, friction performance of brake pads are ensured. Futhermore, the brake pad is one of major tuning components in aftermarket, mechanical characteristics of the brake pad are necessary to evaluate for establishing the certification standards of tuning components. This study had performed the five specimen tests for friction coefficients and wear loss rates according to the SAE test specification. Using the instrumented indentation method, yield strength and tensile strength were measured. Friction coefficients, 0.386 - 0.489, and wear loss rates, 1.0% - 3.7% are obtained. The range of yield strength and tensile strength are 21.4 MPa - 105.3 MPa and 39.5 MPa - 176.4 MPa respectively.

• 한국염색가공학회지
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• 제13권1호
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• pp.9-17
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• 2001

The purpose of this study is to present basic data for the enzymatic modification of acetate fabrics. The weight loss and rate of weight loss of acetate fabrics increased with increasing NaOH concentration and treating time. Acetyl value decreased as the weight loss became higher. The weight loss of alkaline-treated acetate fabrics were directly proportional to the concentration and treating time of cellulase. The optimum temperature and pH in cellulase treatment were $55^\circ{C}$ and pH 3.5. The surface shape revealed that density of fiber decreased by alkaline-treatment. With the treating time of cellulase, fibrillation occurred. In case of higher weight loss in alkaline treatment, fibril is removed after 180 min. The tensile strength decreased by alkaline and cellulase treatment. Especially, in case of higher weight loss of alkaline treatment, tensile strength decreased suddenly. Alkaline treatment increased the drapability of acetates, while cellulase treatment increased it initially but decreased gradually with treatment time. The dyeability after alkaline treatment was improved for reactive dye, but deteriorated for disperse dye. The cellulase treatment of acetate lowered the dyeability for both types of dyes.

• 전기학회논문지
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• 제67권12호
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• pp.1633-1640
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• 2018

Epoxy resin is a polar thermosetting polymer that is widely employed in different branches of industry and everyday life, due to their stable physical and chemical properties. Of all the polymer materials currently being used in the electrical insulation industry, epoxy resin is the most widely used kind, chosen as the base polymer material in the present study. Composites were prepared according to the mixing ratio (MS: MA, 1: 9, 3: 7, 5: 5, 7: 3, 9: 1)of mixture for Heterogeneous Minerals(Micro Silica:MS, Micro Alumina:MA) (MS+MA). We have investigated for AC electrical insulation breakdown characteristics and the dielectric properties (permittivity, dielectric loss, and conductivity) with frequency changes. The electrical AC insulation breakdown performance was improved with the increase of the mixing ratio of MS according to heterogeneous mineral material mixture(MS+MA). As Dielectric properties, the dielectric constant and dielectric loss increased with decreasing frequency and decreased with increasing MS content ratio of heterogeneous mineral mixture. Tensile strength and flexural strength according to the mixing ratio (MS + MA) of epoxy / heterogeneous mineral mixture were studied by mechanical properties. The performance of mechanical tensile and flexural strength was significantly improved as the fill contents ratio of MS increased.