CFRP적층쉘의 적층구성 및 곡률반경에 따른 관통특성

임광희,조영재,이길성,심재기,김영남,양인영 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

최근 탄소섬유 강화 복합재료(이하 CFRP)는 비강도, 비강성이 높아 경량화가 요구되는 우주항공분야에서 구조용 재료로 널리 이용되고 있다. 본 연구에서는 CFRP 적층쉘의 적층구성 및 곡률반경에 따른 관통 특성을 고찰 하고자 한다. 실험에 사용된 복합재료는 일방향 프리프레그시트로서 적층방법은 〔0₃/90₃〕, 〔0₂/90₂〕s,와 〔0₂/90₃/0〕s, 〔0/90₂/0〕 2계면과 4계면으로 적층하였다. 그리고 다양한 곡률 반경을 적용하였다. (R= 100, 150, ∞). 적층순서에 맞게 적층된 시험편은 경화온도 130℃에서 진공백 성형과정을 오토클레이브로 제작 하였으며 100x140mm 크기로 절단 하였다. 시험편은 강구로 관통시켰으며 ballistic-screen sensor로 속도를 측정하여 충격전 운동에너지와 충격 후 운동에너지를 구할 수 있다. 흡수에너지는 곡률이 커질수록 증가하였으며 4계면 시험편보다 〔0₃/90₃〕s 와 〔0₂/90₂〕s 적층구조를 갖는 2계면 시험편이 흡수에너지가 더 높게 나왔다. Currently, carbon-fiber reinforced plastics (CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and staking sequence on the penetration characteristics of CFRP laminated shell. Composite laminates used in this test are CFRP orthtropic laminated plates, which are stacked with two-interfaces 〔0₃/90₃〕s, 〔0₂/90₂〕s and 〔0₂/90₃/0〕s. 〔0/90₂/0〕s. They are manufactured to varied curvature radius (R= 100. 150, 200 mm and ∞). They are cured by heating to the appropriate hardening temperature(130℃) by mean of a heater at the vacuum bag of the autoclave. Test specimens were prepared with dimensions 100mmx140mm. When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistic-screen sensor located a known distance apart. Absorbed energy increased as the curvature increased. 〔0₃/90₃〕s and [0₂/90₂〕s specimens, which is small interlaminar number, was higher than fore interlaminar specimen.

Sprague Dawley 수컷 랏트에서 Bisphenol A Diglycidyl Ether의 경구 투여에 의한 급성 독성

임재언,양윤정,이태진,홍연표 대한산업의학회 2006 대한직업환경의학회지 Vol.18 No.4

목적: 본 연구는 BADGE의 경구 투여에 의한 급성 독성학적 연구를 수행하여 기존의 연구 결과를 확인하고 추후 내분비계 장애 연구에 필요한 기초자료를 얻고자 하였다. 방법: 수컷 SD 랏트에 0, 1000, 2000, 4000과 8000 mg/kg/day의 BADGE와 DES 0.37 mg/kg/day의 농도를 단회 경구로 투여한 후 14일간 일반 증상 등을 관찰하였고 14일 후 부검하였다. 결과: BADGE를 투여한 모든 군에서 투여 후 3일째에 설사와 다른 일반 증상들이 관찰되었고 체중도 감소하는 경향을 보였다. 특히 8000 mg/kg/day의BADGE를 투여한 랏트에서 투여 후 3일째에 대조군에 비해 유의한 수준으로 체중이 감소하는 것을 관찰할 수 있었다. 일부 BADGE 투여군에서 대조군에 비해 심장(1000, 2000과 4000 mg/kg/day), 간(1000, 2000, 4000과 8000 mg/kg/day)과 전립샘(4000 mg/kg/day)의 무게의 감소가 관찰되었다. BADGE 투여군의 간(1000과 4000 mg/kg/day)과 전립샘(8000 mg/kg/day) 의 상대 무게가 대조군과 차이를 보였다. 고환을 제외한 모든 장기에서 조직학적인 변화는 관찰되지 않았으며 고환에서는 세 정관에서 정자세포의 감소가 관찰되었다. 고환과 부고환의 sperm head 수를 보면, 고환에서만 감소하는 경향을 보였으며 정자의 운동성과 기형은 대조군과 차이가 없었다. 혈장 에스트로겐과 테스토스테론 농도는 대조군과 모든 투여군 간의 유의한 차이가 없었다. 결론: BADGE를 랏트에 경구 투여 하였을 때 1000 mg/kg/day의 수준에서도 일반 독성 및 생식독성을 유발시킬 수 있음을 보여준다. Objectives: Bisphenol A Di Glycidyl Ether (BADGE) is the major component in commercial liquid epoxy resins, which are manufactured by co-reacting bisphenol A with epichlorohydrin. The authors investigated the acute toxicity of BADGE. Methods: BADGE was administered by a gavage to 8 week old SPF Sprague Dawley rats in a single dose of 0 (negative control), 0.37 (Diethylstilbesterol, DES), 1000, 2000, 4000, and 8000 mg/kg/day of BADGE. Each treatment group contained 7 rats. The general status and weight of the rats were observed for 14 days. The rats were anesthetized by ether at 14 days, and the changes in morphology, organ weight, sperm count and motility, and hormone level were measured. Results: All the rats treated with BADGE had diarrhea on the 1st day. The rats administered BADGE at 1000, 2000, and 4000 mg/kg/day showed a soiled perineal region and soft stools with diarrhea until the 3rd day. The 8000 mg/kg/day BADGE rats had diarrhea for two days followed by emaciation, soiled fur, a soiled perineal region, staining around the mouth and were moribund for three to eight days. No weight gain was observed after the 1st day in the 2000, 4000, and 8000 mg/kg/day BADGE rats and after the 7th day in all the treatment groups compared with the control groups. Some treatment groups were observed to have a decrease in the weight of the heart (BADGE 1000, 2000 and 4000 mg/kg/day), liver (BADGE 1000, 2000, 4000 and 8000 mg/kg/day) and prostate (BADGE 4000 mg/kg/day) compared with control group. The weight of the liver was significantly lower in all treatment groups compared with the control group. The relative weight of the liver (BADGE 1000 and 4000 mg/kg/day) was significant lower than the control. No pathological changes were observed in the brain, liver, thyroid, heart, spleen, kidney, lung and prostate. The number of spermatid in the seminiferous tubule in the testes was lower in all treatment groups than the control. The sperm motility tended to decrease with increasing concentration but the sperm count was similar in all treatment groups. The plasma Estrogen and testosterone level were similar in the control and treatment groups. Conclusions: These results suggest that BADGE induces general, hepatic and reproductive toxicity at 1000 mg/kg/day.

CFRP 복합적층판의 적층배향·계면수에 따른 저속충격특성

임광희,박노식,나승우,김영남,이현,심재기,양인영 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.6

In this paper, this study aims at the evaluation on the characteristics of CFRP laminate plates using a falling weight impact tester. The experiment was conducted on several laminates of different orientation. A system was built for measuring the impact strength of CFRP laminates in consideration of stress wave propagation theory using a falling weight impact tester. Delamination areas of impacted specimens for the different ply orientation were measured with ultrasonic C-scanner to find correlation between impact energy and delamination area. Absorbed energy of quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy of a hybrid specimen containing a GFRP layer was higher than that of normal specimens.

절간 고구마를 이용한 RNA 생산에 관한 연구

송재철,이종임,양한철 울산대학교 1985 연구논문집 Vol.16 No.2

RNA생산을 위한 최적 당화조건을 이용하여 생산된절간 고구당화액을 탄소원으로 효모 RNA생산능력이 가장 양호한 Cryptococcus laurentii 균주를 분리하였다. 최적 배양조건을 검토한 결과 질소원으로 ammonium sulfate 0.6%, MnSO₄0.1% 그리고 ca-pantoth-enate 400㎍/l를 무기염류, 비타민류로 각각 첨가하였을 때 최대 RNA 생산능력을 나타내었다. 기본배지의 배양조건을 검토하여 얻은 최종배지에서의 효모 균체당 RNA 생산은 30.2% 증가하였다. During an extensive screening tests of yeast on their RNA formation it was found that Cryptococcus laurentii had especially high RNA content and high dry cell weight (D. C. W) in the case of using hydrolyzate of sliced and dried sweet potatoes as a carbon source. Under the above conditions, the RNA content and yield of dry cells were investigated changing the media composition. Ammonium sulfate 0.6% was appeared to be favorable as a nitrogen sources. The optional concentration of Mn?² was showed to be 0.1%. Ca-pantothenate, 400㎍/m1, showed relatively favorable effects as a growth factor. The maximum RNA content of dry cell weight was 16.8% when grown on the medium containing above supplements under the optimal conditions.

플륨 모니터링에 의한 SM45C 레이저 용접특성 평가

유영태,김재열,노경보,양동조,오용석,임기건,김지환 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.6

With the increased use of lasers in industrial welding applications, techniques for monitoring and controlling these processes become increasingly important. It is very important that we understand the dynamic behaviors of the laser induced plume in welding because the laser induced plume has considerable effects on welding efficiency and the quality of materials. As the plume fluctuation was associated with keyhole instability, unstable vapor plume indicated the process was unstable and would result in poor welds. An Infrared Themal-vision Camera can be utilized compensate for incurracies encountered in real-time monitoring during laser welding. We have results that instabilities of plume are closely dated with hot cracking and defect of laser welding.

한국 근해안강망어업의 조석에 따른 주간 어황변동 추세 분석

김진영,황진수,임양재,홍승현,연인자,황학진,김지연 한국수산자원학회 2003 한국수산자원학회지 Vol.6 No.-

조류의 강세에 의존하여 조업이 이루어지는 근해안 강망어업의 어황이 조석에 따라 어떻게 변동하는지를 연구하기 위하여 1994년부터 1996년까지 주간 어획량, 조업척수, 척당어획량의 자료를 판매량이 증가하는 조금 전후와 그 반대의 현상이 나타나는 사리 등으로 구분하여 시계열분석기벅으로 장기변동추세를 분석하였다. 단계별 구분에 따른 어획량에 대한 분석결과, 3단계 구분에서 전체적으로 모형의 적합도가 가장 높게 나타났다. 3단계로 구분한 경우의 어획량은 조금에 (1-0.6891B+2.1168B²)(1-B)Z₁=(1-0.9730B)a_(?) 사리에 Z_(t)=(1+0.41659B)a_(t₁) 중간물에 (1+1.38253B+0.63391B²)Z₁-(1+1.15390B+0.64547B²)Z₁-(1+1.15390B+0.64547B²)a_(t)로 표현되었으며, 조업척수는 조금에 (1-0.19699B)Z₁=(1-0.66259B)a_(t?) 사리에 (1+0.45672B)Z₁=1+0.006094B)a_(t?) 중간물에(1.0.74814B) Z₁=((1-0.21476b)a_(t)로 표현되었다. 척당어획량은 조금에 (1-0.54709B+0.26967B^(6))Z_(t)=a_(t₁) 사리에 (1-0.26622B-0.28067B^(6))(1+0.45081B^(8))Z_(t)=(I+0.21652B^(15))a 중간물에 (1-0.23881B-0.10487B^(5))Z_(t)=a_(t)로 나타낼 수 있었다. Z_(t)는 시간 t에서의 어획량, 조업척수, 척당 어획량을 나타낸다. B는 후향연산자 로서 ㅇ?P를 들면 B^(d)를 Z_(t)에 작용시키면 Z_(t-d)이 된다. A seasonal Autoregressive Integrated Moving Average (ARIMA) time series model was applied to the weekly prediction of landings. number of operating boats and catches per unit effort of large stow net fisheries as ebb and flow in Korean wafers for 1994-1996. The estimated seasonal ARIMA models are presented as the fellowing equations:(1-0.6891B+2.1168B²)(1-B)Z₁=(1-(0.9730B)a₁ at the neap tides. Z₁=(1+0.41659B)a₁ at the spring tides, and (1+1.38253B+0.63391B²) Z₁=(1+1.15390B+0.64547B²)a₁ at the middle tides between the neap tide and the spring tide fer landings.(1-0.19699B) Z₁=(1-0.662593)a₁ at the neap tides. (1+0.45672B) Z₁=(1+D.0.006094B)a₁ at the spring tides, and (1-0.74814B) Z₁=(1-0.214766)a₁ at the middle tides between the neap tide and the spring tide for the number or operating boats, and(1-0.54709B+0.26967B)Z₁=a₁at the neap tides, (1-0.26622B-0.28067B^(6))(1+0.45081B^(8)) Z₁=(1+0.21652B^(15))a₁ at the spring tides, and (1-0.23881B-0.10487B^(5)) Z₁=a₁t the middle tides between the neap tide and the spring tide for the catch per unit efforts, where: :Z_(t)=the value at week t: B^(D)=a backward shift operator that is used as follows: B^(D)Z_(t)=-Z_(t-p); and a_(t)=error term at week t. The prediction error by the Box-Cox transformation on weekly landings, number of operating boats and CPUB of stow net in Korea were less than that by the Iogarithmic transformation.

Wave-front Guided LASIK과 기존의 LASIK 후 3개월 임상 결과 비교

양승재 ( Yang Seung Jae ) , 김태임 ( Kim Tae Im ) , 차흥원 ( Cha Heung Won ) 대한안과학회 2004 대한안과학회지 Vol.45 No.1

표지방류조사에 의한 참홍어 (Beringraja pulchra)의 이동 및 성장률

임양재 ( Yang Jae Im ),조현수 ( Hyun Su Jo ) 한국수산해양기술학회 2015 수산해양기술연구 Vol.51 No.2

To obtain geographical range and growth.kinetics parameters of mottled sake (Beringraja pulchra) populations in the Yellow Sea, three mark.recapture experiments were carried out. Overall, 991 tagged individuals were released, and 4.1% of them were recaptured with the mean release period of 339 d (range, 8.1,420 d) and the mean growth rate of 1.4 cm mon.1 (female, 1.5 cm mon.1; male 1.3 cm mon.1). In the first experiment, 667 individuals were released at Heuksan Island from April to June, 2007.2009, and 30 individuals were recaptured mainly at the north and the north.east coasts of the island, indicating absence of migration to the south of the island. In the second experiment, 323 individuals were released at several fishing grounds scattered in the Yellow Sea in 2010.2013, and 11 individuals were recaptured at points deviated to all directions from the releasing points. As the last, one individual was released with pop.up satellite archival tag at a costal point (34°37.2``N, 124°59.3``E) off Hong Island on May 21, 2010. The tagged individual migrated to a north.east location (35°50.4``N, 126°03.6``E) of Eocheong Island by Aug. 25, 2010. The data archived for the three months in the tag indicated that the migration path had depths of 48.80 m and temperature of 12.6.14.4℃. The results indicated that mottled sake populations had a localized habitat ranges at the north of Heuksan Island and the west of Hong Island while growing at the rate of 1.4 cm mon.1.

1999-2001년 오터트롤에 채집된 황해 동부해역의 어류상

임양재 ( Yang Jae Im ),황학진 ( Hak Jin Hwang ),이재봉 ( Jae Bong Lee ),손명호 ( Myoung Ho Sohn ),연인자 ( In Ja Yeon ) 韓國魚類學會 2009 韓國魚類學會誌 Vol.21 No.4

유리체가 백내장 수술 후 전방 깊이에 미치는 영향

양승재 ( Sung Jae Yang ) , 김태임 ( Tae Im Kim ) , 조범진 ( Beom Jin Jo ) , 차흥원 ( Hung Won Tchah ) 대한안과학회 2004 대한안과학회지 Vol.45 No.9