Correlation Between Primary Si and Silicide Refinement Induced by Ultrasonic Treatment of Multicomponent Al–Si Alloy Containing Ti, Zr, V, and P

Jae‑Gil Jung,Young‑Hee Cho,Tae‑Young Ahn,Jae‑Hee Yoon,Sang‑Hwa Lee,Jung‑Moo Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Sialloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-inducedwetting and deagglomeration of MgAl2O4particles. Lowering the UST finish temperature caused deterioration of the degreeof primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4consumed the MgAl2O4particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phaseon the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4and AlP phases by thesilicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and hightemperatureelongation were increased by UST and were dependent on the size of primary Si.

구리 지역에서 조사한 고혈압의 인지도, 치료률 및 관리률

홍철호,김순길,홍택원,이제,신진호,이재웅,김경수,김정현,임헌길,이방헌 대한간질학회 2003 대한간질학회지 Vol.9 No.1

원심모형시험에 의한 복개터널 복공의 토압특성에 관한 연구

이명욱,박병수,정길수,유남재 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.B

This thesis is results of experimental works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand. Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Compared results model tests estimation with respect to displacements of the lining.

경사진 사석층의 지지력에 관한 원심모형실험 및 수치해석

이명욱,박병수,정길수,유남재 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.B

This paper is an experimental and numerical research works about the effects of the bearing capacity of sloped rubble mound on the density of rubble mound and the position of footing. Centrifuge model tests were performed to investigate the bearing capacity of rubble mound by changing the density of rubble mound and the location of loading in forms of strip loading to simulate the caisson. Materials of rubble mound used in the model tests were crushed rocks having similar value of uniformity coefficient to the value in field. Two different relative densities of 80% and 90% were prepared during tests. The dimens ions of centrifuge model were trapezoidal shape of model mound having the bottom width of mound, 30cm and height of mound, 10cm. Gravity level applied during the centrifuge test was 50G. Surcharge loading in the forms of strip loading was applied on the top of the sloped model mound. Tests were carried out by changing the position of loadi ng. The rigid model footing was located in the center of top of the model rubble mound and the edge of model footing was at the crest of mound. Test results were analyzed by using the limit equilibrium methods proposed by Meyer hof(1957) and Bowles(1982) and the numerical approach with FLAC being available commercially software. For the numerical estimations with FLAC, the rubble mound was simulated with the constitutive relationship of Mohr-Coulomb elasto-plastic model.

일차배양된 설치류 호흡기 상피세포로부터의 점액소 분비에 대한 수종 약물의 영향

이충재,석정호,이재흔,허강민,박지선,배소현,노삼길,박상철 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

1. PKC activator인 PMA는 일차배양 HTSE세포로부터의 뮤신분비를 0.1μM 농도에서 30%, 1μM 농도에서 80% 가량 증가시켰다. 2. 식물 유래 성분으로, flavonoid의 일종인 TFR은 일치배양 HTSE 세포로부터의 뮤신분비를 10μM 농도에서 50%, 100μM 농도에서 80% 가량 증가시켰다. 3. 양이온성 폴리펩티드인 PLL 및 PLA는 일차 배양 HTSE 세포로부터의 뮤신분비를 0.01 - 10μM 농도에서 용량의존적으로 감소시켰다. 4. 결론적으로, 본 연구에서 얻어진 결과들은 새로운 거담제 및 점액용해제나 단백분해 효소제가 아닌 호흡기 류신의 생성/분비를 조절해 줄 수 있는 신개념의 약물을 개발함에 있어 극히 일부분이나마 단서를 제공하고 있다고 하루 수 있을 것이다. In the present study, we tried to investigate whether phorbol myristate acetate(PMA), trihydroxymethoxy-flavanone rutinoside(TFR) and cationic polypeptides significantly affect mucin release(secretion) from cultured hamster tracheal surface epithelial cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 hr and chased for 30 min in the presence of each agent to assess the effect on 3H-mucin release. The results were as follows : (1) Both PMA and TFR significantly increased mucin release from cultured HTSE cells ; (2) Cationic polypeptides including po1y-L-lysine(PLL, mw 7,500) and poly-L-arginine(PLA, mw 10,800) significantly inhibited mucin release from cultured HTSE cells, in a dose-dependent manner. This finding suggests us that PMA and TFR be further studied for the possible use as mild expectorants and cationic polypeptides might function as a regulator for hyper-secretion of mucus, both by direct acting on airway mucin-secreting cells, during the treatment of chronic airway diseases.

자동차용 시로코팬의 유동특성에 관한 연구

이행남,박길문,이덕구,정한별,김건일,설재림 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1

The sirocco fan is used to get low noise, and it has been applied to a lot of industry field like the heat engine, the fluid instrument power plant, the food industry, environment industry etc... because there are not problems even it is mixed with a any kind of liquid, gas, and solid. The flow characteristics in sirocco fan are investigated by PIV. The experiment using PIV measurement for Test section's flow characteristics acquired velocity distribution, Condition : when sirocco fan in automobile air controller maximum 1450RPM, and a revolution is a variation (l)950RPM, (2)l100RPM, (3) 1250RPM. The agreement a experiment shows the validity of this study and the results of this study would be useful to the engineers who design for the flow systems

작업의 특성에 종속되는 병렬기계의 일정계획을 위한 발견적 기법

이동현,이경근,김재균,박창권,장길상 한국경영과학회 2000 經營 科學 Vol.17 No.1

In the real world, situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools, fixtures, or material handing equipment in this paper, we consider n-job, non-preemptive and m parallel machines scheduling problem having two machines group The objective function is to minimize the sum of earliness and tardiness with different release times and due dates The problems is formulated as a mixed integer programming problem The problem is proved to be NP-complete Thus, a heuristic is developed to solve this problem To illustrate its suitability and efficiency, a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop Through the experimental results, it is showed that the proposed algorithm yields good solutions efficiently

徒手體操에서 身體各部位의 可動性에 관한 硏究

李栽吉 군산대학교 1986 群山水産專門大學 硏究報告 Vol.20 No.2

The meaning of gymnastic originated from gymnos of Greek, namely nakedness. The worth of gymnastic was recognized to the world by Ling P.H., a originator of Swedish gymnastic, and F. L. Jahn, a representative of German gymnastic. The muscle and joint parts are remarkably developed, when the resisting force is properly inflicted on the body. This paper has been theoretically studied on the maxium movability and connective and mixed exercise. The purpose of this study is on the production of gymnastic exercise without apparatus.

테니스 初步者 Stroke에 關한 硏究 : 群山市 居住 女性들의 Forehand Storoke와 Backhand Stroke를 중심으로

李栽吉,高敬坤 군산대학교 1989 群山水産專門大學 硏究報告 Vol.23 No.2

After learning the beginning course, the result of the game for 30 female beginners who took part in the individual return blow and in formal match was as follows : 1. In the individual return blow, the points they allowed their opponent in a game was 21.9% in case of A -team in comparison with 47.4% in case of B-team. 2. in the informal match, the points they allowed their opponent in a game was 28.8% in case of A-team, but about 68.3% in case of B-team which showed almost 40% higher than A-team. 3. In each items of game, No hit was 11.6%, Net fault was 10.1%, Base Line out was 7,6%, Side line out was 5.2%. In conclusion, we should coach them by emphasizing more the importance of basic posture from the above result.

미소원공결함을 갖는 차량 밸브용강재의 피로크랙진전거동에 관한 연구

이동길,이상열,정재강 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.1

본 연구에서는 자동차 밸브에 사용되고 있는 내열강 STR3과 STR35를 마찰용접한 후 모재, 열영향부 및 접합선(bond line)에 미소 인공결함을 가공하여 피로크랙 발생 및 전파 거동, 피로수명 및 기계적성질의 상관관계를 조사하는 연구를 수행하였다. 평활재의 피로한도시험 결과 STR3의 피로한도는 429.0MPa이며, STR35는 409.4MPa로서 항복강도가 높은 STR3의 피로한도가 약 20MPa이 높게 나타났다. 미소원공결함이 접합선으로부터 1.0mm떨어진 곳에 가공된 시험편의 피로수명은 모재보다 STR3은 약99%, STR35는 약 25%씩 증가한 반면 접합선에 미소원공결함이 가공된 시험편은 모재보다 STR3은 약 20%, STR35는 약 72% 감소하였으며 파괴전 관찰된 최종크랙길이도 크게 감소하였다. 또한 피로크랙길이와 파단수명비의 관계식에 본 시험재료를 적용한 결과 마찰용접 및 미소원공결함의 위치에 관계없이 비례관계가 있음을 알 수 있었다. The fatigue crack propagation characteristics were investigated for two kind of heat-resisting steel, STR3 and STR35, commonly using in valve material of vehicles, in order to evaluate the fatigue crack propagation behavior and fatigue life of dissimilar friction welding zone. The fatigue limits of the as-received specimens, STR3 and STR35, were 429MPa and 409.4MPa respectably. The fatigue life of the specimen showed about 99.1% for STR3, about 25.2% for STR35 higher than that of the base metal specimen. But the fatigue life of bond line notched specimen was shown about 20% for STR3 and about 72% for STR35 shorter than that of the base metal specimen.