Microstructure‑Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Soo‑Bae Kim,Young‑Hee Cho,Jae‑Gil Jung,Woon‑Ha Yoon,Young‑Kook Lee,Jung‑Moo Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al–Si alloy in a temperature range of 750–800 °Cand its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a hightemperature, which is about 100 °C above the liquidus temperature, had little effect on the grain refinement but enhanced thehomogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, α-Al and intermetallics)significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found tosuppress the formation of Cu-bearing phases, i.e., Q-Al5Cu2Mg8Si6, Al2Cuphases that form in the final stage of solidificationwhile notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increasein the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment withinthe matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanismcovering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

홍당무 모자이크바이라스에 관한 연구

김은수(Woon Soo Kim),최예진(Yae Chin Choi) 한국식물학회 1963 Journal of Plant Biology Vol.6 No.2

KIM, Woon Soo* & CHOI, Yae Chin**(University of Ill., U.S.A.* & Chunchon Agricultural Coll.**) Studies on the viruses of radish mosaic. Kor. Jour. Bot. VI (2):9-21, 1963. A mosaic diseased radish collected from the suburb of Seoul, in November, 1961 was used for studing the host range, physical properties, purification, insect transmission, and electron microscopy. A Japanese strain of raddish mosraic (RPV) was also used with Korean strain of radish mosaic (KRMV) for a comparative study. The two viruses, KRMA and RPV, were identified by the difference in host range, insect transmission and electron microscopy. The KRMA was severely infective on tobacco and Nicotiana glutinosa, while on Gomphrena globosa was immune to the virus. RPV produces necrotic local lesions on Comphrena globosa but did not infect tobacco and N. glutinosa. Among varieties of radish, Seoul, Akamaroo, Akanagea, Koong-Joong showed more severe symptoms than Simoo, Minong, Paek-soo, which appeared to be fainly resistant. In a number of tests, it was found that the virus KRMA retained its infectivity until to a dilution of 1:2,000, heating at 58˚C for 10 minutes, and aging in vitro for 7 days at room temperature. The RPV was not inactivated until it was diluted to 1:2,000, heated to 56。C, and aged for 6days. The KRMV was readily transmitted by the aphid (Myzus persicae Sulz). The virus RPV was not transmitted by the aphid in a number of tests. Partialy purified viruses using ammonium acetate buffer, salting-out by ammonium sulfate and centrifugation of high and low speed were highly infective. Electron micrographs showed that the KRMV paticles are of spherical particles whereas the RPV particles are rod-shaped.

Linear Combination Analysis Using GPS Data

Park, Woon-Yong,Lee, Dong-Rak,Back, Ki-Suk,Hong, Jung-Soo 東亞大學校 建設技術硏究所 2005 硏究論文集 Vol.28 No.2

We can process and compute the position, velocity and time by satellite signals of GPS. The signals are used to compute positioning of three dimensions and timing offset of the receiver clock when we can track the tour satellite signals at least. One of the specified aims is to use less expensive single frequency code/carrier phase GPS receivers, which are typically around half the price of dual frequency receivers. In the study, the author analyzed the accuracy and applicability of frequence linear combination using triangulation points evaluated distance limitation.

골프 지속 행동에 영향을 미치는 참여결정요인 분석

박수정,김학운 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.4

The purpose of this study was to Exploratory analysis of the determinants on golf participants, in order to meet this purpose, this study used qualitative research method. Comprehensive selection strategy was used for selecting of research informants. The participants of this study are consisted of 2 males and 3 females of which have engaged in golf, This study employed In-Depth interview Method. On the basis of the procedure, the conclusions were drawn as follows; The participation determinants factors of golf participants were 4: significant others, goal, ecstacy, competition. The conclusion suggested that understanding of various experience such golf participants go through is deemed highly meaningful as it will trigger a change in terms of concepts of leisure as well as behavior towards leisure in a positive way, which will, in turn, change overall life patterns of individuals while enhancing quality of life.

RTK GPS를 이용한 구조물 모니터링 시스템의 구축

박운용,김진수,안상준 동아대학교 건설기술연구소 2003 硏究報告 Vol.27 No.1

Such social infrastructures as bridges. buildings, dams and towers have been transformed by their own load or by their fundamental ground, or they have been behaved by other external causes. These regular of irregular behaviors threaten to break up themselves or to do their users harm. Therefore, to monitor the load of the structures or reaction shown by them could help to verify their behaviors. RTK GPS allows the use of a static base station and remote rover unit(s) to allow for data collection within several seconds and in real time. Among GPS methods, first of all, we used RTK GPS to analyze the precision of monitoring and then on the basis of it, we developed a monitoring system using RTK GPS when we measured the behavior of main tower of Hyoun-Soo Gyo by using RTK GPS method and IMU, which was an inertia navigation system. Comparing a deviation between observation value using IMU and RTK GPS, X axis was 1㎜, Y axis 1㎜ and z axis 2.2㎜. It turned out that it was possible to monitor and measure structures by RTK GPS method. Besides, in order to manage the structures and prevent their disaster, the transformed monitoring, which used dynamic RTK GPs measurement method, was applied in real time. It was applied in real time. It was verified that it could be used as transformed monitoring measurement method for massive structures.

고순도 단백질 재료 분리를 위한 Lysozyme 농도분석에 관한 연구

김운수,김우식,김용욱 慶熙大學校 材料科學技術硏究所 1995 材料科學技術硏究論集 Vol.8 No.-

In this study the lysis reaction of lysozyme to Micrococcus lysodeikticus cell(ML cell) was investigated to develop the quick and accurate assay technique for lysozyme concentration. For the investigation of the lysis reaction of lysozyme the Michaelis-Menton(M-M) reaction mechanism was applied and Lineweaver-Burk plot was used to calculate the reaction rates. The concentration of lysozyme and ML cell were changed from 2.0 to 10.0mg/l and from 10 to 50mg%, respectively. In these range of concentrations of the lysozyme and ML cell the lysis reaction was good agreement with M-M reaction mechanism and then the maximum reaction constant and Michaelis-Menton constant were measured as 1.40×10^(-2) and 11.08, respectively. These information on the lysis reaction contributes to the better analysis of lysozyme concentration in comparison with conventional procedure.

錦江水系의 自淨能力 推定에 관한 硏究

陸雲洙 관동대학교 1984 關大論文集 Vol.12 No.2

A literature review was carried out to estimate the Self-purification Constants of Kum-River which flow through Dae-Jeon and middle state region of which is concerned with by many people. Thought the research was performed based on insufficient date, the estimated selfparification constants 4.32∼1.8 seemed reasonable. According to the results, It Seems that deoxyogenation constants estimated to be 0.422∼0.626 based on flows rate and that not all of the formula proposed for computation of reoxygenation constants are adugeate for Kum-River leboratory and onsite researchs are recommeded to contism the results of this research.

단수수 條斑細菌病에 대한 品種間 抵抗性 差異와 羅病菌의 窒素 및 糖 含量과의 關係

金明運,白壽鳳,閔庚燦 건국대학교 1969 學術誌 Vol.10 No.1

This experiment was undertaken with the purpose of obtaining the basical data on the culturing techniques, breeding and plant protection in the cultivating of Sweet sorghum in Korea. The Sweet Sorghum 11 U.S. varieties, 2 Japanese and 2 Koreans were cultivated unders the natural condition in infecting of disease. The investigation was performed on the varietal difference in the resist trance to bacterial strip disease and the nitrogen and sugar contents in diseased leaves, and correlation between the diseased ratio and several agronomic characteristics. The results obtained are as follows. 1) It was no found that the variety exempted from disease, White collier, Missouri groytop, Rex, Rurier Var-1 and Atlas were more resisted in certain degree, Sorip-zong (Small grain var.) Tracy, Chinese, Zeuk-Jaelaizong and Honey-I were resited in medium degree and Early sumac, Sugar drip, Red amber, Ames amber and Rex orange were weaker in resistant to disease. 2) In the Correlation between the heading data and degree in resistant disease, generally, medium maturing varites were relatively strong resistant, laste varieties were weakest with exception of very few varieties. 3) In the correlation and regression between the several agronomic characteristics and diseased ratio, the curium lenth and weight of curium had no significant differences, heading date had r= -0,591*, y=90,822-0.354x and brix degree had r= -0.68**, y=19,992-0,246x. 4) The leaves of resistance varieties were more contained the nitrogen, sugar and increased C/N ratio than those of susceptibles.

지상측량과 GPS 관측값을 이용한 결합 망 조정에 관한 연구

박운용,신상철,김진수 동아대학교 건설기술연구소 1999 硏究報告 Vol.23 No.2

Monitoring networks for tectonic studies and for large scale structures often require the combination of terrestrial and GPS observations. The advantage of GPS is its high precision and almost universal applicability, e.g. the connection of stations within the deformation zone to remote, geologically stable areas. The terrestrial techniques are well established and sometimes more precise, and allow to include stations with restricted GPS visibility, i.e. stations at the wall of a dam or in a narrow valley which cannot be determined by GPS. Till now normally the terrestrial and GPS observations are treated separately, a combination is done on the base of adjusted coordinates with or without covariance information. In this paper, for a rigorous combined adjustment of terrestrial and GPS observations the datumfree-concept is proposed. This concept is exact from the mathematical model of adjustment, adequate from the physical model of the observations and extremly flexible from the computational view point.

항공사진 영상을 이용한 정밀 수치정사사진의 생성

박운용,이인수,이기부,김진수 東亞大學校 大學院 1999 大學院論文集 Vol.24 No.-

From early plane-table photogrammetry through the analog and analytical stages, photogrammetry has now reached the digital photogrammetry stage using the image stored at computers. Digital Photogrammetry using aerial photograph generates the DTM and digital orthophoto. Expecially, DTM is important for improving the accuracy of digital orthophoto. so Many experimental are required. In this study, therefore has deals with the generation process of digital othophotos using DTM with breakline and without breakline.