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수소 장입된 극저온용 철강 소재의 수소 취화 특성 평가 Part I : 수소 장입량 비교
김재웅,김성환 한국기계기술학회 2021 한국기계기술학회지 Vol.23 No.5
Due to global warming and environmental pollution, environmental regulations are getting stronger, and the International Maritime Organization announced regulations to reduce CO2 emissions in 2018. In order to respond to this, interest in hydrogen energy is growing, and research on liquid hydrogen is spotlighted for storage and transport of large amounts of hydrogen. Hydrogen reduces in volume to 1/800 when liquefied, but its boiling point is close to absolute zero(-253°C), and hydrogen embrittlement that penetrates other materials and weakens mechanical properties. In this study, the change of mechanical properties under cryogenic conditions (-196 degrees below zero) was confirmed after charging hydrogen into existing cryogenic materials (Stainless steel, High Manganese steel, 9% Nickel steel). In Part I, hydrogen was charged using an electrochemical method and quantitative evaluation was performed. In all four materials, as the changing time increased, the diffusible hydrogen concentration increased. After 24 hours charging, the hydrogen loading of 20 wppm in 9% Ni steel and 15 wppm in high-Mn steel was confirmed. In a follow-up study, we plan to study the effect of hydrogen charging by comparing the results of the mechanical properties test with the above results.
LNG연료추진탱크용 ASTM A553M-17 소재의 파이버 레이저 변수에 따른 Bead on Plate 특성 연구(PART II : BOP 속도 & Energy density)
김재웅 한국기계기술학회 2021 한국기계기술학회지 Vol.23 No.4
Due to stricter environmental regulations of the International Maritime Organization (IMO), the number of ships fueled by Liquefied Natural Gas (LNG) is rapidly increasing. The International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) limits the material of tanks that can store cryogenic substances such as LNG. Among the materials listed in the IGC Code, ASTM A553M-17 has been recently adopted as a material for LNG fuel tank projects because of its excellent mechanical properties at cryogenic temperatures. In shipyards, this material is being used to build tanks through Flux Cored Arc Welding (FCAW). However, there is a problem that magnetization occurs during welding and there is a big difference in welding quality depending on the welding position. In order to overcome this problem, this study intends to conduct basic research to apply laser welding to ASTM A553M-17 material. As a result of analyzing the bead shape according to laser BOP speed and Energy density performed in this study, it was confirmed that the penetration and energy density are proportional but the penetration and BOP speed are inverse proportional to some extent. In addition, a range of suitable welding speed and energy density were proposed for the 6.1mm thickness material performed in this study.
선박용 고망간강 소재 파이버 레이저 Bead on Plate (BOP) 실험적 연구(PART 2 : 아르곤,헬륨보호가스)
김재웅 한국기계기술학회 2022 한국기계기술학회지 Vol.24 No.3
Environmental regulations of the International Maritime Organization (IMO) are getting stricter, and the demand for replacing the fuel of ships with eco-friendly fuels instead of heavy oil in the shipbuilding and marine industries is increasing. Among eco-friendly fuels, LNG (liquefied natural gas) is currently the most popular fuel. This is because it is an alternative that can avoid the IMO's environmental regulations by replacing fuel. In PART 1, as a basic study of laser welding of high manganese steel materials, a fiber laser bead-on-plate experiment was conducted using nitrogen protective gas, and the effect of each factor on the penetration shape was analyzed through cross-sectional observation. In PART II, argon and helium shielding gases, not the nitrogen shielding gas used in PART I, were tested under the same experimental conditions and the effect of the shielding gas on penetration during laser welding was conducted.
교사 평가의 정치학: 새로운 교사 평가제의 도입 및 시범운영 과정을 중심으로
김재웅 한국교육정치학회 2008 敎育政治學硏究 Vol.15 No.1
자율, 경쟁, 분권, 탈규제 등의 가치를 추구하고 있는 소위 신자유주의의 물결 속에서 평가는 평가 대상 세계에 대한 질 관리, 경쟁력 강화, 그리고 고객 만족을 위한 필수적인 요소로 간주되고 있다. 평가에서 상대적으로 자유로웠던 교육 분야도 이제 평가로부터 더 이상 자유롭지 않다. 교사 평가는 기술적·방법적 행위일 뿐만 아니라 정치적 행위이다. 교사 평가를 위한 목적과 문제를 설정하고, 그 목적을 달성하기 위한 평가의 대상과 방법을 결정할 때 이미 정치적 선택을 하고 있는 것이다. 평가 결과를 어떻게 해석할 것이지, 그리고 평가 결과 가운데 어떤 것을 선택적으로 더 강조할 것인지 결정하는 일은 정치적 맥락 안에 들어와 있는 것이다. 새로운 교사 평가제의 주요 쟁점인 평가의 목적, 평가의 주체, 평가의 내용, 그리고 평가의 방법에 대한 정부의 결정에 대하여 이해집단들이 어떻게 반응하고 갈등하고 있는 지 살펴보았다. 새로운 교사 평가제는 관련 법률의 입법 절차를 남겨 놓고 있다. 앞으로 이해집단들 간의 상이한 입장을 고려할 때 성공적인 입법과 집행을 예견하기가 쉽지 않다. 교사 평가의 목적이 교사의 전문적 능력의 향상에 있다면, 교사 평가를 외부의 기준에 따라 일방적으로 적용하는 관료적 통제에서 자유롭게 풀어주는 한편, 교육에 직접 참여하고 있는 교육의 주체들이 수업을 포함하여 어떻게 하는 것이 교사의 역할을 멋있게 수행하는 것인지에 대해 서로 배울 수 있도록 해야 할 것이다. Evaluation has been regarded as a 'must' in order to assure the quality, to strengthen the competitiveness, and to enhance customer satisfaction, which is closely related to so-called Neo-Liberalism pursuing the values of autonomy, competition, and deregulation. Teachers and schools are not free from evaluation anymore. Teacher evaluation is not only a technical act but also a political one. To identify the problems, to set up the goals of evaluation, and to decide the methods of evaluation are political decisions. How to interpret the results of evaluation, how to utilize them, and how to pay relative attention to the results are the matters of politics. New teacher evaluation in Korea has been tried out three times with an aim to facilitate the professionalism of teachers, being expected to be legalized by June 2008. But it is not easy to forsee the successful legalization and implementation, for different interest groups have different voices about the new evaluation. Teachers, by and large, are in a strong opposition to the implementation of new teacher evaluation, while parents and the government are for it. This paper tried to identify the different views among the key players such Ministry of Education, teachers organizations, parent organizations, and the mass media in terms of the goals, subjects, contents, methods of teacher evaluation. If the goal of teacher evaluation is to increase teachers' professional capacity in teaching, it needs to free teachers from top-down evaluation from the bureaucratic control as well as to provide educational participants with opportunities to learn from each other about what the best instruction is and who the best teachers are.
김영삼 정부의 교육정책 결정 구조와 과정: 5.31 교육개혁안을 중심으로
김재웅 한국교육정치학회 2015 敎育政治學硏究 Vol.22 No.2
This study tried to explain the policy-making process of the Kim Young Sam Government, relying on the review of related literature, as two stages as follows: at the first stage policy agenda was set up by the Presidential Commission on Education Reform(PCER) in cooperation with Secretary to the President for Education, and Ministry of Education began to activate the policy formation process through the legalization for the policy tasks, which needed the help form the side of the National Parliament or Cabinet Council. The PCER, fully supported by the President, took the initiative during the whole policy process. It was told that neo-liberalism was pervaded in the May 31 Educational Reform, propagated by non-education experts working for the PCER in accordance with the Presidential Secretary. The guidelines were followed by the specification procedures played by the educational experts in the PCER with rationality and professionalism. Mass-communication, interest groups, and educational scholars were involved in the policy process in a positive and cooperative mood, which contributed to the successful policy formation. Also, the Ministry of Eduction, especially the Minister and the high-level bureaucrats, being responsible for the response to the command from the President given as May 31 Educational Reform, played the key role in the policy-making process, which was highlighted in the legalization. The National Assembly, The Cabinet Council, and the Ministry itself were participated in terms of the level of the policy measures. Little problem was found in this process under the supportive atmosphere. Finally, teachers’associations need to participate more actively in the policy-making process, and the educational reform organization at the central government as a permanent legal institution needs to be established for the stable implementation of educational reform policies. 이 연구는 김영삼 정부의 교육정책 결정 구조와 과정을 문헌연구에 의존하여 분석하였다. 연구결과, 교육개혁위원회가 청와대 비서실과 긴밀한 협조관계 속에서 정책의제를 던지고, 교육부가 중심이 되어 국회 등의 도움을 받아 해당 법률의 제정 또는 개정을 통하여 정책결정에 참여하였음을 밝혔다. 의제설정 과정에서 가장 주도적으로 역할을 수행한 집단은 대통령의 지지를 받고 있던 교육개혁위원회이다. 신자유주의의 흐름이라는 개혁의 방향에 대해서는 교육개혁위원회 내의 비교육계 인사들이 청와대 비서실과의 조율 속에서 주도하고, 구체적인 개혁안의 수립에는 합리성과 전문성을 지닌 전문위원 등 교육계 인사가 주도적인 역할을 수행하였다. 이어지는 교육정책 결정 과정에서는 5.31 교육개혁안을 입법화할 책임을 지고 있는 교육부가 핵심적인 역할을 수행하였으며, 교육부 장관과 장관을 보필하는 행정고시 출신 고급 관료들의 역할이 두드러졌다. 그리고 개혁안과 관련된 법률의 수준에 따라 국무회의와 국회가 협조적으로 참여하였다. 교육정책결정 과정에 교사집단의 보다 적극적인 참여가 요구되며, 국가 수준의 법률적 기구로서 교육개혁 담당기구를 둘 필요가 있다.
선박용 9%니켈강 소재 고효율 서브머지드 아크 용접 실험적 연구
김재웅,김유진,조주연,여태곤,김영현,표창민 한국기계기술학회 2022 한국기계기술학회지 Vol.24 No.2
Due to the environmental regulations of the International Maritime Organization (IMO), the number of ships using cryogenic fuel such as LNG (liquefied natural gas) is increasing rapidly, and the demand for eco-friendly ships is expected to grow further in the future. The material of the tank for storing cryogenic fuel such as LNG is limited within the IGC Code, and available materials include 9% nickel steel, Invar (36% nickel steel), Al5083-0, STS304L, and high manganese steel. Recently, 9% nickel steel has been used as a tank in LNG fuel-powered ship projects, and it has excellent thermal/mechanical properties in cryogenic LNG environmental conditions (-163°C). In this study, it is conducted an experimental study on SAW(Submerged Arc welding), which has better welding efficiency than FCAW(Flux Cored Arc Welding), which is mainly used for 9% nickel steel materials. In addition, to verify the reliability of the welded part after the welding test, cross-sectional observation of the welded part was performed and the mechanical properties such as the tensile strength and cryogenic impact strength of the welded part were evaluated.