• Journal of Welding and Joining
• /
• 제12권4호
• /
• pp.117-126
• /
• 1994

APAL (Aramid Patched ALuminum alloy) was manufactured, which was a material that was consisting of a A12024-T3 aluminum alloy plate bonded to single-side of it with aramid/epoxy laminates. The aramid/epoxy laminates were bonded to it in condition of 1, 2 ply and fiber orientation of .+-.45, 0.deg./90.deg. Fatigue crack propagation tests were performed at stress ratio R-0.2, 0.5 with Al 2024-T3, APAL 45-1P, APAL 0/90-1P, APAL 45-2P, APAL 0/90-2P specimens to examine behavior of retardation in fatigue crack propagation. All the APAL specimens showed superior fatigue crack resistance. Number of cycle spended for crack to propagate from $a_{M}$=37 to $a_{M}$=65 mm in case of APAL 0/90-2P specimen was half that of Al 2024-T3 specimen. Fatigue crack propagation rate of APAL 0/90 specimens were retarded more compared to APAL 45 specimens and the amounts of retardation at R=0.5 were larger than that at R=0.2. It was found that the retardation in fatigue crack propagation was caused by intact fibers in the wake of crack.ack.

• 한국해양공학회지
• /
• 제11권4호
• /
• pp.31-39
• /
• 1997

This research is to evaluate the effect of sunshine treatment on the strength in the Al 6061/AFRP hybrid composite(APAL). APAL specimens were processed by autoclave curing system under the constant condition of curing temperature, time and aluminum surface pertreatment. Aramid patched aluminum alloy can be widely used for the repair of the damage part of the aircraft. The tensile strength of the sunshine treated APAL 2P and 6P composite is 14%, 22% smaller than that of the non-treated material. The interlaminar shear strength of the APAL specimens for the adhesive length of 5mm is 24% higher than that of the APAL for the adhesive length of 10mm. In the case of APAL DS 1P material, interlaminar shear strength of the specimen which was sunshine treated for 200 hours is 21% smaller than that of the non-treated material while interlaminar shear strength of the specimen which was immersed in a 70.deg. C fresh water for 1200 hours decreases by 75.7%.

• 대한기계학회논문집
• /
• 제19권4호
• /
• pp.1013-1022
• /
• 1995

A hybrid composite (APAL;Aramid Patched ALuminum alloy, CPAL;Carbon Patched ALluminum alloy), consisting of a Al 2024-T3 aluminum alloy plate sandwiched between two aramid/epoxy and carbon/epoxy laminate, was developed. Fatigue crack growth behavior was examined at stress ratios of R=0.2, 0.5. The APAL and CPAL showed superior fatigue crack growth resistance, which may be attributed to the crack bridging effect imposed by the intact fibers in the crack wake.

• 한국해양공학회지
• /
• 제11권3호
• /
• pp.69-75
• /
• 1997

A A12024-T3 plate has been reinforced with AFRP to be a Hybrid-Composite, APAL. The fatigue life of the APAL has been investigated. The effects of bonding surface, numbers of AFRP bonded and AFRP orientation on fatigue life have been compared with A12024-T3 plate. Fatigue life of APAL has been remarkedly increased compared with that of A12024-T3 plate. The fatigue life has depended on bonding surface and AFRP orientation, but no relationship could be found with numbers of AFRP laminates.

• 대한기계학회논문집A
• /
• 제24권7호
• /
• pp.1810-1816
• /
• 2000

A hybrid composite APAL(Aramid Patched Aluminum alloy) , consisting of Al 2024-T3 aluminum alloy plate sandwiched between two aramid/epoxy laminates, was developed. The characteristics of tensile s trength were investigated and statistical properties of tensile strength were studied in terms of Weibull distribution probability with number of AFRP laminates. The tensile strength of APAL was inproportional to number of AFRP laminates and followed the two-parametic Weibull distribution.

• 약학회지
• /
• 제30권6호
• /
• pp.294-300
• /
• 1986

New antibiotics having moieties of penicillanic acid, cephalosporanic acid and ampicillin on both ends of the central polyalkylene were synthesized by reacting 6-aminopenicillanic acid (6-APAl), 7-amino cephalosporanic acid (7-ACA) and ampicillin with hexamethylene diisocyanate and sebacoyl chloride, respecetively. Antibiacterial activities of the compounds were also investigated.

• 환경생물
• /
• 제36권3호
• /
• pp.352-358
• /
• 2018

본 연구는 PCR 기반 RFLP (Restriction Fragment Length Polymorphism; 제한절편 길이 다형성) 분자기법을 활용하여 난 및 치어 대상 납자루아과 어류 3종의 동정을 좀 더 빠르고 정확하게 파악하고 납자루아과 어류의 종별 산란양상 및 번식생태 이해에 대한 기여가 목적이다. 본 연구를 위해 기존 선행된 문헌자료를 확인하고 납자루아과 어류가 2종 이상 동서하고 있는 지역을 확인하여 현지조사를 수행하였다. 현지조사 결과 확인된 납자루아과 어류는 묵납자루(Acheilognathus signifer), 줄납자루(A. yamatsutae) 및 각시붕어(Rhodeus uyekii)로 총 3종이 확인되었으며, 확인된 납자루아과 어류와 동서하고 있는 숙주조개(작은말조개; Unio douglasiae sinuolatus)를 채집하여 숙주조개 속 납자루아과 어류의 난 및 치어를 확보하였다. 현지조사 결과 확인된 납자루아과 어류 3종을 대상으로 미토콘드리아 DNA COI과 cyt b 유전자 염기서열을 비교하여 각각 종별로 특이성을 지닌 부위(단일염기변이; Single Nucleotide Variation: SNV)에 맞는 제한효소를 선정하였고, 숙주조개 속 난 및 치어를 대상으로 genomic DNA를 추출하여 PCR-RFLP 실험을 수행한 결과 현지조사 시 확인된 납자루아과 어류 3종의 독특한 제한절편 길이 양상을 전기영동을 통하여 확인하였다. 본 연구를 통해 묵납자루, 줄납자루 및 각시붕어의 종을 판별할 수 있는 RFLP 마커를 개발하였으며, 숙주조개 난 및 치어를 대상으로 정확한 종의 동정을 보다 빠르고 효과적으로 수행하여 각각 납자루아과 종별 산란양상을 보다 정확히 규명하고 향후 이들 자연개체군의 효과적인 유지, 관리 및 보전 방법 개발에 유용하게 활용될 수 있을 것으로 판단된다.