Effect of Impact Velocity on Interface Characteristics of HT‑9 Steel Joints Fabricated by Magnetic Pulse Welding

Jun‑Woo Song,Jin‑Ju Park,Gyoung‑Ja Lee,Min‑Ku Lee,Kyu‑Hyun Park,Soon‑Jik Hong,Jung Gu Lee 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3

The weldability window in magnetic pulse welding (MPW) is proposed for the end-closure joining of HT-9 steel tubularworkpieces. Based on both theoretical and experimental investigations, the impact velocity of the flyer tube at the momentof collision had a dominant effect on the bonding characteristics of the resultant joints and the optimal impact velocity wasestimated to be in the range of 265–290 m/s in this alloy system. Under the optimal process conditions, no leak was detectedduring helium leak testing. Moreover, the integrity of the joint interface was preserved until the tube section ruptured duringinternal pressure burst testing. For HT-9 steel, the ductile δ-ferrite phase produced by the localized interfacial melting duringMPW acted as an effective obstacle to crack propagation, thereby enhancing the fracture resistance of the joint interface. Allof the results demonstrated the high integrity and durability of the HT-9 steel tube assembly fabricated by the MPW process.

용사코팅용 나노 WC-12Co 피드스톡의 제조

전형우,김주선,박준영,박종구,황순영,이해원 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4

This study investigates the fabrication of WC-12Co feedstock powders with weakly locculated slurries by spray drying under various conditions. The morphological defects and flocculation states according to the amount of additives are evaluated to prepare spherical WC-Co feedstock powders with little morphological defects and homogeneous microstructures. The characteristics of feedstock powders, heat treated between 850-1200℃, are analyzed via SEM, EPMA, and mercury porosimetry. The results showed that with the increase in heat treatment temperature the portion of larger pores around 10 μm increased while, that of smaller pores of 1 μm lessened due to the coalescence of WC particles, forming dense feedstock powders with little defects such as hollow or craters. The feedstock heat treated at 1200℃ showed a porosity of 42.2% and a density of 8.28 g/cm^(3) as well as uniform distribution of pores and Co. (Received January 19, 2004)

이온교환체로서 Polyphenylene Sulfide Sulfonic Acid에 관한 연구

전병광,손원근,서구원,맹학영,김동철,송해영 충남대학교 공업교육연구소 1994 論文集 Vol.17 No.1

Sulfonated poly(phenylene sulfide)(S-PPS) was prepared by the reaction of poly(phenylene sulfide)(PPS) with fuming sulfuric acid. The sulfonation was confirmed by the high intensity band of the SO_3H group at 1190 cm^-1. Thermally crosslinked S-PPS was used for a cation exchange polymer with high thermal stability. The ion exchange capacity of soluble S-PPS(H-form) and insoluble S-PPS(H-form) was 5.16meq/g and 3.50meq/g, respectively. The ion exchange capacity and IR absorbance at 1190cm^-1 of S-PPS were decreased as the curing temperature was increased.

大學內의 弘報機能과 大學新聞의 役割에 關한 硏究

李俊球 弘益大學校 敎育硏究所 1978 敎育硏究論叢 Vol.- No.1

This paper aims at the basic study to establish a theory for active use of the function of Public Relations in the college. But this study does not present some concrete plans, for it is carried out only through the references or books. To restore the academic reliability in the college, school authorities should stop the one-way publicty of its policy. The function of public relations should be reexamined for the expression of professors' and students' opinions and active exchange of mutual intention. Overall attention should be paid to college newspaper which plays an improtant part in bringing about effective public relations.

朝鮮朝 末期의 近代化에 있어서 敎育과 내셔널리즘에 관한 硏究 : 그 成立過程과 役割構造를 중심으로

李俊球 弘益大學校 敎育硏究所 1986 敎育硏究論叢 Vol.- No.2

In this article, the writer has closely observed how our education and nationalism were established and developed, and what role they played for the modernization of the nation during the later period of the Yi Dynasty, especially between the years of 1860 and 1910. He conducted the historical study: A. In terms of the subject, he observed 1) the modernization 2) the nationalism 3) the education. B. In terms of the point of view, he observed 1) the interaction of modernization and nationalism 2) the interaction of nationalism and education 3) the interaction of education and modernization reaching a conclusion that the three conceptions are closely related, eventually leading to conception of trinity. C. In terms of the contents, he found that Historically, nationalism and modernization are closely related. In Korea, its modernization and nationalism were developed in such inseperable relationship. It is particularly noteworthy that desire for modernization and "people's sovereignty conception" greatly prevailed among the Koreans at that time. The latter is actually nationalism itself. In this context, modernization and nationalism interacted strongly and closely, accelerating the development of modern education.

朝鮮朝 開化期의 新·舊敎育의 葛藤과 變容에 關한 硏究

李俊球 弘益大學校 1988 弘大論叢 Vol.20 No.1

This article is concerned with what educational heritage the educational innovation of later Yi Dynasty, the prime achiever of the national enlightenment, received from our ancestors, and with how the new education was established and developed on the traditional background of ideology. There were serious conflict and confrontation between the conservatives who stuck to the dualistic pholosophy based on Confucianism and the liberals who advocated educational innovation. Such conflict and confrontation nearly made the Korean education too invalid to struggle against the over-whelmingly surging "European Shock." However, fortunately, our educational leaders had wisdom to take advantage of this crisis to solidify our national conciousness. Therefore, it con be asserted that the new education was started on the dual basis of modernization and national identity. Further, this new education movement took its root as national educational pholosophy even under the Japanese rule, eventually leading to a prime factor of the March lst Independence Movement.

日本「開放大學」에 關한 調査硏究 : The university of Tsukuba 「Open University」System

李俊球 弘益大學校 1982 弘大論叢 Vol.14 No.1

The founding philosophy of the University of Tsukuba is in many respects that of an 「open University」 both in national terms and in international terms. Existing Universities are often confined in Marrow specialty arers, inviting the stagnation and hardening of both research and technology and encouraging isolation from real Society, The University of Tsukuba. with this problem in mind, maintains a constant relationship with changing modern Society, and a flourishing international character, while developing more over, a new organization for he functions and administration of research and teaching on a basis of diversity and flexibility. The objectives of the University are therefor, in respect of the pure and applied sciencs, to doepen free and rigorous exchange and liaison between the organs of reseach and teaching on the one hand, and Society at home and abroad on the other hand; to pursue research and teaching while bringing internasonal Cooperation to fruition, and there by to educate able people with a creative intelligence and arich humanity;and to Contribute to the development of science and culture.

林停秀詩의 硏究

許俊九 翰林大學校 泰東古典硏究所 1993 泰東古典硏究 Vol.10 No.-

비외상성 두개내 출혈 환자에서 심근손상의 발생과 예후에 미치는 영향

강구현,황성호,이강현,조준휘,김성환,문중범,박해상,이서영,이성수,김헌주 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

Objective: The aim of this study was to investigate the clinical significance of myocardial injuries in patients with nontraumatic intracranial hemorrhage by identifying the occurrence of myocardial injury and defining its correlation with subsequent cardiovascular events. Subjects and methods: One hundred twenty-four patients with nontraumatic intracraninal hemorrhage presented to the emergency department within six hours from onset of symptoms were enrolled. Brain CT, serial electrocardiography, and echocardiography were done at the emergency center. Blood samples for troponin I and creatine kinase(CK)-MB were drawn immediately and eight hours after admission, Troponin I and CK-MB were measured using a chemiluminescent immunoassay, respectively. Results: Electrocardiographic and echocardiography abnormalities were found in 65 cases(52.4%) and 21 cases(17%), respectively. Serum troponin I and creative kinase-MB were increased in 35 cases (28.2%) and in 58 cases(46.8%), respectively. Abnormal findings of echocardiography and ECG, as well as elevated levels of serum troponin I and creative kinase-MB, were associated with an increased risk of cardiovascular event and survival. Logistic regression analysis revealed that an abnormal echcocardiographic finding and elevation of serum troponin I were factors associated with the occurrence an adverse cardiovascular event and that electrocardiographic abnormalities and initial mental status were factors associated with poor prognosis. Conclusion: This study reveals that actual myocardial injury develops in a significant proportion of patients with nontraumatic intracranial hemorrhage and that the development of the myocardial injury is associated with an adverse cardiovascular event that occurs during admission.

제지폐수의 응집특성에 관한 연구

조준형,정원구,김준환 江原大學校 森林科學硏究所 1998 Journal of Forest Science Vol.14 No.-

본 연구에서는 우유팩을 이용하여 재생용 화장지를 만드는 제지공장의 제지폐수를 이용하여 폐수의 침강특성 및 SS, BOD_5, 제거 효율을 검토하고, Jar-tester를 이용하여 급속교반시간, 완속교반 시간에 따른 탁도, SS, BOD_5 및 최적 응집제 주입량을 결정하였다. 각종 응집제 첨가 및 침강 특성에 의한 탁도제거의 효율을 측정하였다. 적정 응집제 첨가량, 급속교반 및 완속교반의 시간에 따른 처리 효율의 이론식을 제시하였다. 또한 응집제 Polyalunlinium chloride(PAC) 및 Aluminium sulfate의 응집 비교 실험을 행하였다. Sedimentation characteristics SS, BOD_5 and removal efficiency of waste water in the tissue paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity. SS and S-BOD_5 and then equation for treatment efficiency was suggested. For the coagulant, polyalumimium chloride(PAC) are compared with a little better efficiency compare to the aluminium sulfate.