Microstructure, Tensile and Fatigue Properties of Al–5 wt.%Mg Alloy Manufactured by Twin Roll Strip Casting

Joon‑Young Heo,Min‑Seok Baek,Kwang‑Jun Euh,Kee‑Ahn Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5

This study investigated the microstructure, tensile and fatigue properties of Al–5 wt.%Mg alloy manufactured by twin rollstrip casting. Strips cast as a fabricated (F) specimen and a specimen heat treated (O) at 400 °C/5 h were produced andcompared. In the F specimen, microstructural observation discovered clustered precipitates in the center area, while in theO specimen precipitates were relatively more evenly distributed. Al, Al 6 (Mn, Fe), Mg 2 Al 3 and Mg 2 Si phases were observed. However, most of the Mg 2 Al 3 phase in the heat-treated O specimen was dissolved. A room temperature tensile test measuredyield strength of 177.7 MPa, ultimate tensile strength of 286.1 MPa and elongation of 11.1% in the F specimen and167.7 MPa (YS), 301.5 MPa (UTS) and 24.6% (EL) in the O specimen. A high cycle fatigue test measured a fatigue limit of145 MPa in the F specimen and 165 MPa in the O specimen, and the O specimen achieved greater fatigue properties in allfatigue stress conditions. The tensile and fatigue fracture surfaces of the above-mentioned specimens were observed, and thisstudy attempted to investigate the tensile and fatigue deformation behavior of strip cast Al–5 wt.%Mg based on the fi ndings.

식중독균 항원(Salmonella typhimurium)에 의한 계란항체(IgY) 생산성과 항체특성 및 항균효과

백경연,손규목,배만종,백반석,한준표 경산대학교 생명자원개발연구소 1999 생명자원과 산업 Vol.3 No.-

본 연구는 식중독균을 항원으로 하여 산란계에 면역시킨 후 계란 항체(IgY)의 생산 가능성을 검토하고, 그 항체의 특성과 항균성을 조사하고자 실시하였다. 그 방법으로는 항원으로 사용된 Salmonella typhimurium(ATCC 14028) 등을 incomplete Freund's adjuvant와 동량으로 혼합하여 면역시킨 후 10주간 생산된 계란을 수집하여, 계란항체(IgY)의 분리 및 식중독균 항원에 대한 항체의 특성, 항균성, 생화학적 특성을 측정하였다. S. typhimurium 항원에 면역된 산란계의 계란항체(IgY)생산 및 증가를 측정한 결과, 산란계가 이들 항원에 면역반응을 일으켜 2주 후 혈청과 난황에서 각각 normal군에 비하여 뚜렷한 항체가 생성능을 보였으며, 혈청내의 IgG생성에 비하여 계란항체(IgY)의 생성이 다소 낮은 것으로 나타났다. 혈청 및 난황내의 단백질 함량은 normol군에 비하여 약간 높은 경향을 나타내어 산란계의 혈청 및 난황내의 단백질이 이들 항원에 의하여 증가하는 것으로 나타났다. DEAE-Sephacel column을 통과한 fraction은 두 개의 peak를 나타내었다. 각 fraction의 IgY농도를 ELISA법으로 확인한 결과 두 번째 peak에서 대부분 측정되었다. 분리 정제된 IgY의 분자량을 SDS-polyacrylamide 전기영동법으로 측정한 결과, heavy chain 72∼75KD, light chain 30∼40KD정도였다. Anti-S. typhimurium 항체의 온도에 대한 활성은 60℃에서 30분 가열시 91.5%, 65℃에서 15분 가열시 각각 73.2%의 활성도를 나타내었으며, 80℃에서 15분간 가열시는 거의 활성이 없는 것으로 나타났다. pH에 대한 안정성은 pH 7부터 pH 4까지는각각 98.7%의 활성도를 유지하다가 pH 3부터 급격히 감소하여, pH 2에서는 9.6%로 거의 활성도를 나타내지 않았다. 항균활성을 응집가, 생균수, disc diffusion susceptibility test 등으로 측정한 결과 anti-S. typhimurium 항체의 항균활성도는 매우 미약하게 나타났다. 이상의 결과에서, 본 실험에서 사용된 IgY는 항원에 대한 특이성 및 생화학적 특성 등을 고려해 볼 때 앞으로 식중독균 제거 및 예방 치료뿐만 아니라 식품산업 소재, 각종 질병예방을 위한 의약품 소재, 연구용 kit와 진단용 kit 및 축산분야 등 여러 분야에 응용될 수 있으리라 기대된다. This study was carried out to investigated to get a industrial information from discussion about productive a possibility if IgY antibody, antimicrobial activity and properties of IgY antibody in egg yolk. Immunoglobulin Y in egg yolk and immunoglobulin G in serum were obtained from gens which were immunized with Salmonella typhimurium(ATCC14028). These antibody titers were evaluated in serum and egg yolk by ELISA. After the initial immunization the anti-Salmonella typhimurium IgY antibody level gradually were decreased from firth week to tenth week. On the other hand, the antibody level in the serum were increased from the first week, reaching its peak in the sixth week. The residual antibody activities of IgY were 91.5% after heating for 30min at 60℃. At the same time, were 73.2% after heating 15min at 65℃ and decreased vapidly at 70℃ and little antibody activity was left after heating for 15min at 80℃. When the prepared IgY was stable from pH 7 to 4 and remained to 69.8% at pH 3, respectively.

식중독균 항원(Salmonella typhimurium)에 의하여 생성된 계란항체(IgY) 특성과 항균 효과

백반석,한준표,배만종 동아시아식생활학회 1999 동아시아식생활학회지 Vol.9 No.2

This study was carried out to get a industrial information about a possibility of IgY antibody production, antimicrobial activity and properties of IgY antibody in egg yolk. The residual antibody activities of IgY were 91.5% after heating for 30min at 60℃. At the same time, these activities, were 73.2% after heating 15min at 65℃ and decreased vapidly at 70℃ and little antibody activity was left after heating for 15min at 80℃. When the prepared IgY was incubated at various pH ranges from 7 to 2 for 5hr at 37℃, the antibody activity was stable from pH 7 to 4 and remained to 69.8% at pH 3.

Wavelet Transform을 이용한 시청각 학습시의 전두부 뇌파 활성도에 관한 연구

이준탁,정소라,백승일 동아대학교 정보기술연구소 2006 情報技術硏究所論文誌 Vol.14 No.1

Real-time estimating brain waves is useful method in studies like brain activity state. And the frontal-lobe of cerebrum is important behavior for something new which intention response and consideration activities. In this paper, analyze the frontal-lobe Waves of cerebrum using wavelet, Furier transform during 5 times repeated new visual education teaching to middle school student. Many researches be attempted to find relation in concentration and emotion with the specify brain waves. There are three waves called α,β,θ waves generated by brain and it's related memory factor and continuous concentration in reseaches. a-wave, one of the three waves generated by brain which is identified that participating in motivate brain activities like attention and memory sequences. So analyze pattern and activity of a-signal in EEG-signals which changing in study sequence of student using wavelet transform for high analysis efficiency in signal processing in this paper.

Butyl cyanoacrylate가 성견 치은절제술후의 치유에 미치는 영향

백상철,박준봉 慶北大學校 齒科大學 1989 慶北齒大論文集 Vol.6 No.3

The purpose of this study was to observe the comparative clinical and histological changes associated with healing following the use of cyanoacrylates and no dressing in the 1st molar areas where gingivectomy procedures had been carried out. In this experimental study, 5 adult mongrel dogs were used and each dog divided into one control and the other experimental areas. The dogs were sacrificed on the 3rd, 7th, 14th, 21th, and 28th day. The experimental areas were observed clinically, and histological specimens were made following the usual methods and observes with light microscope. The results were as follows. In the clinical observations. immediately after the gingivectomy, postoperative hemostasis was made more rapidly on the experimental areas. On the 3rd day, the majority of the cyanoacrylate on the experimental areas were detached, and the complete detachment of the cyanoacrylate was observed on the 7th day. In the histologic observations, the experimental areas as compared with the controls:there was a thiner covering of fibrotic pseudoepithelium, and lesser edematous fibrous matrix and weaker inflammatory cell infiltration on the lower connective tissue was shown on the 3rd and 7th day. The extension of the blood vessels of the experimental areas was lesser than the control areas. But through the entire procedure of the histologic observations, there was little difference between two in the degree of healings after the 14day. On the 28th day, there was secondary inflammation on the both areas because of dental plaque and food debris.

1996년 5월 한국 남해 및 서해 연안역의 해양환경과 식물플랑크톤 군집동태

이준백 제주대학교 해양연구소 1998 해양자원연구소연구보고 Vol.22 No.-

The characteristics of marine environment and phytoplankton community dynamics have been investi- gated in the southern and western coastal waters of Korea in May, 1996. Water temperature. salinity. and transparency varied in the range of 9.3~16.0%. 31.7~35.5% 0.4~9.2 m respectively. The concentration of total inorganic nitrogen and phosphate phosphorus distributed in the range of 1.86~62.42 P M and 0.08~0.86 μM. respectively. showing relatively high nitrogen in the southern waters and relatively high phosphorus in the western waters. The N/P ratio were higher in the southern waters than in the western waters. It is believed that the southern waters have been more eutrophicated by the nitrogen sources in Korean waters. A total of 44 species of phytoplankton occurred including 22 spp. of diatom. 21 spp. of dinoflagellate. and 1 sp. of silicoflagellate. The standing crops of phytoplankton were in the range of 1.5 x10^(3(~46.6x10^(3) cells l^(-1), relatively higher abundance in the southern waters than in the western waters. Dinoflagellate was much abundant in the southern waters. which is likely to be related to the eutrophication of the southern waters. Whereas the western waters showed relatively low standing crops. Particularly a benthic diatom. Paralia sulcata (Ehrenberg) Cleve. was most dominant in all most western stations. where this species would be resuspended by the physical movement of water rather than any chemical factors involved in the shallow water.

춘계 한국 남서해역 식물플랑크톤의 공간적 분포

이준백 濟州大學校 海洋硏究所 2003 해양과환경연구소 연구논문집 Vol.27 No.-

춘계 한국 남서해역의 식물플랑크톤의 공간적 분포 특성을 2000년 5월에 총 15개 정점의 표층, 30m, 50m 층에서 조사하였다. 조사시기의 식물플랑크톤 현존량은 전 정점에서 3.23×10⁴∼1.09×10^(7) cells·ℓ^(-1) 범위로 전 정점 평균은 1.62×10^(6) cells·ℓ^(-1)이었다. 우점종은 총 11종이었으며 규조류가 9종. 식물편모조류가 2종으로 규조류가 높은 우점을 보였으며 Skeletonema costatum이 전 정점에서 가장 높은 우점을 보였다. 식물 수문학적 분포를 분석한 결과 조사해역은 4개의 수역으로 구분되었다. Ⅰ 수역은 연안성 종류가 많이 분포하는 연안역, Ⅱ 수역은 중간역, Ⅲ 수역은 외양성 종류가 많이 분포하는 외해역, Ⅳ 수역은 기타 수역으로 분류되었다. 또 Ⅱ 수역은 Skeletonema costatum가 표층과 30m 층에서 춘계 대발생을 나타내었으며 북쪽 방향으로 뻗어 나가는 분포 특징을 보이고 있다. Spatial distribution of phytoplankton was investigated in the southwestern sea of Korea in May 2000 in terms of phytohydrography. Sampling was done at the 0m, 30m, 50m of 15 selected stations, and permanent sides of each samples were prepared by QPS method for quantitative and qualitative analyses. Phytoplankton standing crops ranged from 3.23×10⁴ to 1.09×10^(7) cells·ℓ^(-1) in the study area. Dominant species comprised of 9 diatoms and 2 phytoflagellates, showing high dominance by diatom and most predominance by Skeletonema in all layers of most stations. Phytohydrographic results indicate that the study area might be divided into 4 categories. that is. Ⅰ area is designated as neritic area where terrestrial and coastal species occur frequently. Ⅱ area as intermediate area, Ⅲ area as offshore area 조ere oceanic species dominate. and Ⅳ area as the others. Especially in the Ⅱ area. Skeletonema costatum was most predominant at both surface and 30m layers in most stations and represented an characteristic of northward expansion with spring massive bloom.

제주도 한림항과 성산항 일대 식물플랑크톤의 군집동태

이준백,좌종헌 제주대학교 해양연구소 1990 해양자원연구소연구보고 Vol.14 No.-

2009년 인플루엔자 대유행 중 인플루엔자 진료소 방문자의 연령 분포 변화

김백남,곽이경,문치숙,김연숙,김의석,배인규,염준섭,이창섭,허지안 대한감염학회 2010 감염과 화학요법 Vol.42 No.2

The pandemic influenza (H1N1 2009) virus, after being introduced in Korea in April, 2009, spread rapidly nationwide in mid-2009. This study was conducted to characterize trend in age distribution of visitors to Flu-clinics during the pandemic. Demographic, clinical and laboratory data of visitors to flu clinic from Week 36 to 52 (August 30 to December 26) of 2009 were retrieved and collected from electronic databases at 9 hospitals. Visitors 0-6, 7-12, 13-18, 19-29, 30-64, and 65 years or more of age were classified into group I to VI, respectively. A total of 107,467 visitors were seen at Flu-clinics for a 17-week study period. Of those, 32,485 were laboratory-confirmed. Antivirals were prescribed for 62,533 visitors. Numbers of visits, prescriptions of antivirals, and laboratory-confirmed cases of the pandemic influenza (H1N1 2009) peaked at Week 44. A large number of visits by group II and III were followed by those of group I and V, especially around the peak. Numbers of visits by group VI were lowest in all hospitals. In some hospitals, higher number of visits lasted longer in children than in adults while vice versa in other hospitals depending on the location. In summary, the pandemic influenza (H1N1 2009) was presumed to peak in late October and involved majorly children and students in Korea. Unique age distribution of visitors to flu clinic was observed in some hospitals.

소방호스 밀착강도시험방법에 관한 연구

김준배,백창선,김학진 한국화재소방학회 2001 한국화재소방학회논문지 Vol.15 No.1

소방호스의 밀착강도 시험방법을 개선하기 위하여 5개국(한국, 미국, 영국, 중국, 일본), 7개의 기술기준(KOFEIS, UL, NFPA, BS, 중국기술기준, JIS, 일본검정기술기준)을 비교 고찰하고, 국내에서 생산되는 소방호스를 무작위로 발췌하여 밀착강도시험을 실시하였다. 밀착강도시험 및 기술기준 비교 고찰을 통하여 밀착강도시험은 소방호스의 호칭별로 시험시효의 크기와 박리시험속도 및 판정기준을 세분화함으로서 소방호스의 밀착강도를 개선시킬 수 있다는 결론을 얻었다. In order to improve the adhesion test methods for fire hose, 7kinds of stands (KOFEIS, UL, FM, NFPA, BS, Chinese standard, JIS, JFEII standard) un 5 countries (Korea, USA, UL, China, Japan) were compared and adhesion tests were conducted by using the samples choosed randomly from the product produced in Korea. It was concluded that the sample size, the rate of seperation of a strip of the lining from the jaket and standard judgment should be more differed and divided in accordance with the fire hose number in adhesion test to get the high qualily of fire hose