• Composites Research
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• 제29권5호
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• pp.276-281
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• 2016

본 연구에서는 돌침대용 석재/목재 복합재의 열적특성 및 접착특성 개선에 대한 연구를 진행하였다. 기초 물성을 체크하기 위해 인장실험을 진행하였고 석재 및 목재의 실시간 온도측정을 진행하였다. 석재/목재 복합재의 가열부위에 따른 열적 특성을 알아보기 위해 석재를 위로 두었을 때와 목재를 위로 두었을 때 두 가지 방법으로 가열을 실시하였다. 에폭시 접착제에 CNT를 넣음으로써, 열적 및 접착특성의 변화를 알아보기 위하여 실시간 온도측정과 랩 전단 실험을 실시하였다. 실험결과 목재를 위로 두었을 때 열적 특성이 좋은 것을 확인하였고 에폭시 접착제에 CNT를 넣음으로써 접착특성 및 열적특성이 개선됨을 볼 수 있었다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.343-356
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• 2011

This paper proposes an accelerated life evaluation of drive shaft. The life test of drive shaft for independent suspension type AWD vehicle should be performed by use of the least test sample because many number of samples can't be used for the test because of its mass capacity and high price. We calculated the no failure test time by application of no failure test concept, and the already performed test data for drive shaft are applied for some kinds of reliability coefficients which are needed for calculation of life test time. And, for analysis of real driving condition of vehicle, the load spectrum is prepared using the needed road condition and vehicle data. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved by use of Miner's Rule, and then the final accelerating condition is determined by decision of the accelerated test torque. This paper shows that the accelerated life test results corresponds with the target life and the proposed life test method can be very well applied to no failure life test for mass capacity machinery components.

• 동력기계공학회지
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• 제5권2호
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• pp.57-62
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• 2001

Gas turbine performance is highly dependent on the engine performance which is closely related to the engine materials since they are exposed to severe working environments, i.e, high temperature and high stresses. For this reason, advanced materials with improved properties are required for the engine. The purpose of this research is to develop key materials technologies for aircraft industry and to tester domestic production of related parts. In this paper, the real-time prediction of high temperature creep strength and creep life for nickel-based superalloy Udimet 720(high-temperature and high-pressure the gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and $704^{\circ}C$.

• KSBB Journal
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• 제23권4호
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• pp.303-310
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• 2008

소의 혈액, 세포, 조직, 기관 등 소유래 물질을 원료로 사용한 생물의약품, 조직공학제제, 세포치료제의 경우 소유래 원료물질에 다양한 바이러스가 오염된 사례가 있기 때문에 바이러스 안전성 검증이 필수적이다. BPIV3는 동물 세포주, 우혈청 등에 가장 흔하게 오염되는 바이러스이다. 소유래 물질을 원료로 하는 생물의약품, 조직공학제제, 세포치료제 등에서 BPIV3 안전성을 확보하기 위해, 원료물질, 제조공정, 완제품에서 BPIV3를 정량적으로 검출하고, 제조공정에서 BPIV3 제거 검증을 위한 시험법으로 활용이 가능한 BPIV3 real-time RT-PCR 시험법을 확립하였다. BPIV3에 특이적인 primer를 선별하였으며, 형광염료 SYBR Green I을 사용하여 BPIV3 RNA 정량 검출 시험법을 최적화하였다. 세포배양법에 의한 감염역가와 비교한 결과 real-time RT-PCR 민감도는 2.8 $TCID_{50}/mL$이었다. 확립된 시험법의 신뢰성 (reliability)을 보증하기 위해 시험법 검증을 실시한 결과 특이성 (specificity)과 재현성 (reproducibility)이 우수함을 확인하였다. 확립된 real-time RT-PCR을 생물의 약품 제조공정 검증에 적용할 수 있는지 확인하기 위하여 인위적으로 BPIV3를 오염시킨 CHO 세포주와 소유래 콜라겐에서 BPIV3 검출 시험을 실시하였다. BPIV3를 감염시킨 CHO 세포와 세포배양 상청액에서 BPIV3를 정량적으로 검출할 수 있었다. 소유래 콜라겐에서도 7.8 $TCID_{50}/mL$ 까지 정량적으로 검출할 수 있었다. 위와 같은 결과에서 확립된 BPIV3 real-time RT-PCR 시험법은 생물의약품 안전성 보증을 위한 세포주 검증, 생물의약품 생산 공정 검증, 바이러스 제거 공정 검증 등에서 감염역가 시험법과 같은 생물학적 시험법을 대신할 수 있는 신속하고, 특이성과 민감성이 우수한 시험법임을 확인하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권4호
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• pp.1823-1828
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• 2016

Background: Biological and pharmacological activities of dryocrassin ABBA, a phloroglucinol derivative extracted from Dryopteris crassirhizoma, have attracted attention. In this study, the apoptotic effect of dryocrassin ABBA on human hepatocellular carcinoma HepG2 cells was investigated. Materials and Methods: We tested the effects of dryocrassin ABBA on HepG2 in vitro by MTT, flow cytometry, real-time PCR, and Western blotting. KM male mice were used to detect the effect of dryocrassin ABBA on H22 cells in vivo. Results: Dryocrassin ABBA inhibited the growth of HepG2 cells in a concentration-dependent manner. After treatment with 25, 50, and $75{\mu}g/mL$ dryocrassin ABBA, the cell viability was 68%, 60% and 49%, respectively. Dryocrassin ABBA was able to induce apoptosis, measured by propidium iodide (PI)/annexin V-FITC double staining. The results of real-time PCR and Western ting showed that dryocrassin ABBA up-regulated p53 and Bax expression and inhibited Bcl-2 expression which led to an activation of caspase-3 and caspase-7 in the cytosol, and then induction of cell apoptosis. In vivo experiments also showed that dryocrassin ABBA treatment significantly suppressed tumor growth, without major side effects. Conclusions: Overall, these findings provide evidence that dryocrassin ABBA may induce apoptosis in human hepatocellular carcinoma cells through a caspase-mediated mitochondrial pathway.

• 한국가정과교육학회지
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• 제1권1호
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• pp.63-85
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• 1989

The Change of environment related to human life, science, technology, economics and education level have much effect on home life. Therefore Home Economics Education have to get out of past trite concept that it is only a method to become good housewife and take the role to widen the human life and to grow creative power as a academic part of science. For these, Home Economics should become life education, life education of secondary school has to have relation to lifelong education. To achieve effective result from Home Economics Education, the object, system and methods of Home Economics Education, the object, system and methods of Home Economics Education have to be improved and teaching material has to be studied systematically. As an object of aboves and education planning in clothing is made for deep understanding the study of Home Economics Teaching Material. And to understand the real state, made some questions, had interview with 63-teaching in Kangweon province and show the results. 1) Tab 1~20 are the level of recognition about object, teaching content, time structure of secondary school. The object is recognized as cultural education and basic job education. 2) Tab 21~30 show the real state of textbook and study of it. To take effect from school lecture other teaching material except textbook is required. 3) Tab 31~40 are the result of sewing and handicraft practice. Sewing and handicraft needs much time and almost all time is used in practicing. 4) Tab 42~54 are the planning of textbook study for effective teaching, self-estimation and teaching material making is also considered. All above is collarless blouse’s planning. Base on above result, all objects of clothing life should be teached. For the development of Home Economics Education 1) Understanding and affection of teachers is required. 2) To solve indicated problem, national policy, education plan in school and education finance are fully supported. 3) More studies is required in Home Economics Education.

• 소성∙가공
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• 제19권7호
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• pp.435-440
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• 2010

The creep life of 9Cr1MoVNb steel, in terms of Larson-Miller parameter(LMP), was evaluated by small punch(SP) creep simulation and verified by uniaxial creep test. By employing the elastoplastic FEM(finite element method), the small punch creep behaviors associated with various friction coefficients were simulated to identify a real friction phenomena. The friction coefficient, ${\mu}$=0.7, determined by comparing deflection history was used in the small punch creep simulation to find the equivalent stresses with which the relationship between punch load and uniaxial creep stress was found. The creep life was then predicted by the LMP, which was the relationship among the rupture time, temperature, and stress. Finally, the LMP calculated by SP-creep simulation was compared with that had computed by the uniaxial creep test and fairly matched LMPs were found.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.108-113
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• 2001

In this paper, the real-time prediction of high temperature creep strength and creep strength and creep life for nickel-based superalloy Udimet 720 (high-temperature and high-pressure gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and 704$^{\circ}C$. The predictive equation of ISM creep has better reliability than that of LMP and LMP-ISM, and its reliability is getting better for long time creep prediction(10$^3$~10sup/5/ｈ).

• 대한기계학회논문집 C: 기술과 교육
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• 제5권2호
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• pp.115-126
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• 2017

본 논문은 특수 차량용 동력 전달계 부품인 구동축의 가속 수명 시험을 수행하는 것이다. 동력 전달계 부품의 수명 평가를 위하여 사용환경의 주행 부하 스펙트럼의 데이터가 필요하나, 특수 차량의 경우 부하 스펙트럼을 구할 수 없는 경우가 대부분이다. 따라서, 본 논문에서는 차량 데이터와 특수 주행로 조건에 기반하여 주행 부하 로드 스펙트럼을 모델링하고 시뮬레이션 하였다. 가속 수명 시험에는 역승 모델을 적용하였고, 마이너 법칙을 사용하여 등가 토크를 구하였으며, 구동축 가속 수명 시험을 위하여 교정 가속법을 사용하였다. 피로시험은 세 수준의 스트레스로 수행하였으며, 사용자 스트레스 수준의 수명은 외삽법을 사용하여 예측 하였고, 실제 시험 결과와 부하 스펙트럼 데이터와의 비교로 수명을 검증하였다.

• Corrosion Science and Technology
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• 제8권3호
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• pp.116-118
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• 2009

Korea Institute of Construction Materials founded Seosan Outdoor Exposure Test Site 2005 at Korea, which is a part of Worldwide Exposure Network (WEN). To evaluate the test site along with other exposure test sites, three different types of paints have been under real time weathering conditions at three major weathering test facilities around the world. Using these test specimens several spectroscopic experiments along with physical tests have been performed. Also acceleration tests have been performed using the same paints. The correlation of weathered paints among three different test facilities and accelerated test results has been compared. From the results the reliability of Seosan Weathering Test Facility and reasonable life time prediction tests are discussed.