CT시편의 구속효과가 파괴저항곡선에 미치는 영향

우홍식,김수용 동국대학교 경주대학 1997 東國論集 Vol.16 No.1

In order to obtain more realistic fracture resistance curve, many researchs are currently underway to introduce new parameter and to quantify the constraint effect. The objective of this paper is to investigate the relationship between the crack tip constraint effect (specimen size, specimen thickness, plane size, crack length ratio and side groove) and the fracture resistance curve. In this paper, fracture toughness tests were performed with various parameters. Test results show that the J-R curve is increased with increase in the plane size and decrease in the crack length and the J-R curve is decreased due to the side groove of specimen. In addition to the effects of the crack length and the plane size on the J-R curve are significant while the effects of specimen thickness and the specimen size on the J-R curve are insignificant.

부식환경에서의 용접재의 피로균열성장거동에 관한 연구

우홍식 동국대학교 경주대학 1993 東國論集 Vol.12 No.-

The objective of this paper is to investigate the effect of residual stress on the fatigue crack growth behavior in corrosion environments. For this purpose, transverse butt submerged arc welding was performed on SM50A steel plate and CT(compact tension) specimens which loading directions are perpendicular to weld bead were selected. And the environments under which the experiments performed were in air, in pure water and 3.5% NaCl solution. From the experimental results and discussin, in region I, the value of ΔK_th, CF in pure water in similiar to that of 3.5% NaCl solution but they are about 1.6-2.1 times that of air environment. In region Ⅱ, also the fatigue crack growth behavior in pure water is similiar to that of 3.5% NaCl solution. But their behaviors were slower than that of air environment. So it is assumed that the fatigue crack growth behavior was affected by more crack closure phenomenon due to corrosion products than the residual stress.

노치재의 균열닫힘현상과 피로균열성장거동에 관한 연구

우홍식,한지원 東國大學校 1993 東國論叢 Vol.32 No.-

Crack length and closure are monitored simultaneously and countinuously in terms of the testing by a PC-aided unloading elastic compliance technique. The relation between the crack opening stress intensity factor and crack length is determined from the experimental results. The crack opening stress intensity factor of short cracks, K_op, can be predicted from the crack opening stress intensity factor of near threshold of long crack, K_op.L. The growth rate of short cracks at notch root can be predicted from the crack opening stress intensity factor of short cracks, K_op, and the growth equation of long cracks in region Ⅱ.

분편 인플루엔자백신(split influenza vaccine)의 임상효과 및 면역원성에 관한 연구

우흥정,김동림,정희진,천병철,이주연,안정배,김지희,박찬,신영규,김우주,김민자,박승철 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.1

목적 : 아단위 인플루엔자 백신 접종 후 백신의 인플루엔자 예방효과, 인플루엔자 방어 항체형성, 인플루엔자 백신의 안전성을 조사하고자 하였다. 방법 : 총 571명을 대상으로 인플루엔자 백신 접종을 하였고, 이들 접종자에서 인플루엔자 양질환의 이환을 조사하여 인플루엔자 백신의 인플루엔자예방효과를 알아보았고, 백신의 접종 전 및 접종 4주 후 혈청에서 혈구응집억제물(Hemagglutination Inhibition : HAI) 항체 검사를 실시하여 백신의 방어항체생성을 조사하였고, 백신의 안전성을 알아보기 위해 백신접종 후 1주일 이내의 부작용을 조사하였다. 결과 :백신 접종군과 백신 비접종군에서 인플루엔자 양 질환의 이환을 조사한 결과 접종군 28.35%, 비접종군 35.88%으로 나왔으며, p 값이 0.001로 통계적으로 접종군에서 유의하게 낮았고, 인플루엔자 양 질환의 예방 효과는 20.97%를 보였다. 백신의 방어항체 형성의 평가를 위해 유럽의 인플루엔자 백신 허가 기준을 조사하였는데 B/Guangdong/5/94균주의 백신접종 후 항체가 40이상의 비율을 제외한 다른 기준은 모두 만족 시켰다. 부작용은 전체 조사자 521명중 149명(29%)으로 주로 접종 부위의 국소 부작용을 호소했고, 전신 부작용은 2% 내외였으며 특별히 심각한 부작용은 발견되지 않았다. 결론 : 분편 인플루엔자 백신은 인플루엔자양질환의 예방과 방어항체생성에 효과 있으며 안전한 것으로 사료된다. Background : The safety and effectiveness of influenza vaccine are well known in developed country. The influenza vaccination has been recommended as one of the tentative immunization schedule for indicated persons since 1997 in Korea. But there are still no available data about them, even though nearly 5 million doses of influenza vaccine were used in 1997-1998 season. So it is immediately needed to investigate the safety. efficacy and immunogenicity of influenza vaccine among Korean. Methods : We studied the clinical efficacy of influenza vaccine by monitoring Occurrence of influenza-like illness in influenza risk group(vaccination ; 300, non-vaccination; 215) from December in 1997 to March in 1998. We used the split quadrivalent influenza vaccine containing 15 microgram of hemagglutinin of A/Beijing/262/95(HlNl), A/Wuhan/359/95(H3N2), B/Mie/1/93 and B/Guangdong/5/94. Hemagglutination inhibition(HA1) antibody titers were determined before immunization and 1 months after vaccination And we evaluated adverse effect of influenza vaccination at 7 days after vaccination. Results : Influenza vaccination was associated with si@icant reductions in influenza-like spptoms(vaccination group; 28.35%, non-vaccination group, 35.88%, p=0.001). The preventive effect of influenza-like i3lne.s among influenza risk goup was 20.97%. And immunogenicity of influenza A and B exceeded all of the European licensure criteria for immunogenicity except postvaccination proportion of titers 240 of B/Guangdong/5/94 strain. And the adverse effects were mainly local injection site problem and no serious adverse effect was noted. Conclusion : Split influenza vaccine is safe, inmunogenic and eff'tive in influenza risk group in Korea.

제품혁신을 위한 창조적 디자인 사고모델(Ⅰ)

우흥룡 서울産業大學校 1995 논문집 Vol.42 No.1

Since cognitive psychology accepts that design information is actively reorganized and reconstructed in memory rather than passively recorded and recalled, it follows that something must control this process. The most well used division is that between "reasoning" and "Imagining", both of which are obviously needed in design. When 'Reasoning’the individual is said to carry out mental operation within some coherent symbolic system. This category is usually held to include logic, problem-solving and concept formation. When’Imagining', on the other hand, the individual is said to draw his own experience, combining material in a relatively unstructured and perhaps aimless was. Design clearly involves both convergent and divergent productive thinking which is probably what maker it so challenging and satisfying to practise. Creativity can be seen not simply as ability for divergent thought but rather a balance of convergent and divergent thinking abilities appropriate to the situation. The author's aim is to produce the BMS Model which is combined with Brainstorming Method, Mind Map and Synectics Method as a Synthesis Method for Creative Thinking. In order to deploy our creative thinking, we use IDES(Industrial Design Evaluation System) which consists of 3 major modules (1.Design Element, 2.Matrix, 3.Evaluation). It is intended to be an aid for design development. The author thinks IDES is a new design development approach which could provide effective creation of design ideas to make design innovation. Therefore BMS Model is an attempt to provide industrial designers with access to design creation.

품종별 쌀의 이화학적 특성과 증편제조 적성과의 관계

우경자,이은아,황홍구,이건순 동아시아식생활학회 1998 동아시아식생활학회지 Vol.8 No.4

This study was carried out in order to investigate the processing adaptability of Jeung-pyun. We used rice materals that were developed domestically for improving the utilization of rice. Six cultivars(Ilpoombyeo, Hwasungbyeo, Dasanbyeo, Daeribbyeo 1, Hyangmibyeo 1, Hyangmibyeo 2) of rice were used for making Jeung-pyun. In physicochemical properties of rice, Hwasungbyeo had the highest amylose content(20.4%) and Hyangmibyeo 2 had the lowest one(14.9%). Lipid content was 0.23%(Daeribbyeo 1)~0.43%(Ilpoombyeo), protein content was 7.94%(Ilpoombyeo)~8.43%(Dasanbyeo), and ash content was 0.15%(Hyangmibyeo 2)~1.24%(Daeribbyeo 1). In volume and specific volume of the 3 hour fermented Jeung-pyuns, Ilpoombyeo, Hwasungbyeo, Hyangmibyeo 2 were higher, but in the 7 hour fermented Jeung-pyuns, Dasanbyeo, Daeribbyeo 1, Hyangmibyeo 1 were higher. In the sensory evaluation of the test Jeung-pyuns, the overall quality of the 3 hour fermented Jeung-pyuns was not significantly different among the rice cultivars, whereas in the 7 hour fermented Jeung-pyuns Hyangmibyeo 2 had the lowest values. When the 7 hour fermented Jeung-pyuns were stored at 20℃, the hardness and brittleness of Jeung-pyuns were respectively increased, the cohesiveness was respectively decreased. The elasticity was not significantly different among the rice cultivars with storage days, and the gumminess was significantly difference between rice cultivars, respectively increasing during storage, but Hyangmibyeo 2 was the lowest, not increased. In instrumental characteristics of Jeung-pyuns, the hardness was correlated with amylose content and the brittleness and gumminess were highly correlated with the hardness.

Ti-50.1at.%Ni합금의 변태거동에 미치는 시효처리의 영향(Ⅰ)

우흥식,박성범,강봉수,김성진 한국안전학회 2004 한국안전학회지 Vol.19 No.4

This study investigated the effects of aging on the transformation behavior of Ti-50.lat.% Ni alloy by means of differential scanning calorimetry. It was found that aging in the temperature range of 350℃~550℃ induced complex transformation behavior, involving the R-phase and multiple-stage martensitic transformation. Usually aged Ni-rich NiTi alloys undergo martensitic transformation on cooling from high temperatures in two step : B2 to R and then R to B19' (normal behavior). But under certain ageing conditions, the transformation can also occur in three or more step(unusual multiple step behavior). In the present study we use differential scanning calorimetry(DSC) for a systematic investigation of the evolution of transformation behavior with ageing temperature and time.

Ti-6Al-4V의 저주기 고온염 피로균열성장거동에 관한 연구

우흥식,강봉수,김봉철 東國大學校 1999 東國論叢 Vol.38 No.-

Fatigue crack growth behaviour of Ti-alloy, Ti-6Al-4V were investigated in air and salt corrosive environments. The temperatures which was tested were room temperature and 200℃. Fatigue crack growth rate is known to be fast for formation of corrosive product by impregnation Ti-Alloy with salt solution in hot salt environment. For the effect on corrosion fatigue crack growth behabiour of sale corrosive transformation in air and high temperature of region Ⅱ, fatigue crack grwoth rate in air atmosphere had a little gap to both case, 200℃ and room temperature. However, it showed very fast tendency especially in salt corrosive atmosphere, and it was remarkably accelerated in 200℃ high temperature salt environment. When ΔK was approximately 30MPa√m, fatigue crack growth rate had a little difference between at room temperature and at 200℃ high temperature, however in case of salt corrosive environment, the former was 3.5 times faster and the latter for 16 times than air environment respectively. For salt corrosive environment of microstructure (Ⅲ), the fatigue life in 200℃ salt corrosive environment was shorter than that of in air, reached to only 32%.

생강나무 잎과 가지의 정유성분 비교

고건우, 홍열, 임흥빈 충북대학교 연초연구소 2008 煙草硏究 Vol.21 No.-

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용접구조물의 건전성 평가법 개발에 관한 연구

우홍식 동국대학교 경주대학 1995 東國論集 Vol.14 No.-

Fracture is an important consideration when evaluating the integrity of welded structure and a number of methods are currently available for assessing the integrity of welded structure. But they are very expensive, expert methods. So more simple evaluation methods are needed. Therefore, the objective of this study is develope an integrity evaluation computer program on welded structure. Finally, computer program base on FAD was developed the welded stuctures and case studies were performed to evaluate the accuracy. In the results, a computer program base on FAD can b e used as an effective tool for evaluating integrity of welded structures.