Insulation Coating of Fe–Si–Cr Soft Magnetic Powder by Selective Oxidation

Jae‑Young Park,Kwangsuk Park,Bosung Seo,Julien O. Fadonougbo,Tae‑Wook Na,Ki Beom Park,Hyeon‑Tae Im,Nong‑Moon Hwang,Hyung‑Ki Park 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

This study examines the insulation coating technology of Fe–Si–Cr powder via selective oxidation annealing, which oxidizeselements selectively by controlling the oxidation potential. The study calculated the oxidation driving force of Fe, Si, andCr, and conducted a thermodynamic analysis of oxidation and reduction conditions according to temperature and oxidationpotential. Based on the results, a selective oxidation annealing was performed in an atmosphere in which Fe is reduced andonly Si and Cr are selectively oxidized. The oxidation potential was controlled through the partial pressure ratio of hydrogenand water vapor. The XPS analysis results confirmed that a Si and Cr complex oxide layer formed on the powder surfaceafter the selective oxidation annealing. Afterward, withstanding voltages were analyzed to evaluate the insulation property. Then, the withstanding voltage of the powder applying the selective oxidation annealing increased significantly comparedto that of the initial powder. Further analysis showed that the powder annealed in an air atmosphere had a significantly lowersaturation magnetic flux density than the initial powder, while the powder applying the selective oxidation annealing hadonly a slightly reduced saturation magnetic flux density.

재외동포 아동 학습자를 위한 한국어회화 교재의 구성원리 및 개발에 관한 연구

김재욱 국제한국어교육학회 2002 한국어 교육 Vol.13 No.2

Jae-Wook Kim. 2002. A Study on the Development and Layout Principles of Korean Conversation Textbooks for Overseas Korean children learners. Journal of Korean Language Education 13-2: 67∼85. The existing Korean conversation textbooks were aimed for non-heritage learners(i.e. foreigners) who have no background knowledge of Korea. They were unsuitable for heritage learners(i.e. overseas Koreans) who have some knowledge of Korea. In this paper, it claims that we must reflect the characteristic of overseas Korean children, that they are not absolutely ignorant of Korea, in textbooks for overseas Korean children. It also points out that unlike the existing textbooks that emphasize the four functions of language, we must integrate the teaching of both Korean language and Korean culture from elementary stages. In addition, we have considered the fact that language education for children is less systematic and analytic than the education for adults in presenting the layout principles for Korean conversation textbooks for overseas Korean children. The textbooks emphasize that the heritage students maximally use their background knowledge in Korean and focus on building their fluency. We believe that Korean conversation textbooks that are made considering the characteristics of overseas will increase the pride in one's homeland and improve the Korean skills of overseas Korean children that attend Korean schools. (Kyunghee University)

Open Posterior Approach versus Arthroscopic Suture Fixation for Displaced Posterior Cruciate Ligament Avulsion Fractures: Systematic Review

Jae­Gwang Song,Kyung Wook Nha,이세원 대한슬관절학회 2018 대한슬관절학회지 Vol.30 No.4

Purpose: To compare the clinical outcomes between the open posterior approach and arthroscopic suture fixation for displaced posterior cruciate ligament (PCL) avulsion fractures.Methods: A literature search was performed on MEDLINE, EMBASE, and the Cochrane Library databases. The inclusion criteria were as follows: papers written in English on displaced PCL avulsion fractures, clinical trial(s) with clear description of surgical technique, adult subjects, a follow­up longer than 12 months and modified Coleman methodology score (CMS) more than 60 points.Results: Twelve studies were included with a mean CMS value of 72.4 (standard deviation, 7.6). Overall, 134 patients underwent the open posterior approach with a minimum 12­month follow­up, and 174 patients underwent arthroscopic suture fixation. At final follow­up, the range of Lysholm score was 85–100 for the open approach and 80–100 for the arthroscopic approach. Patients who were rated as normal or nearly normal in the International Knee Documentation Committee subjective knee assessment were 92%–100% for the open approach and 90%–100% for the arthroscopic approach. The range of side­to­side difference was 0–5 mm for both approaches.Conclusions: Both arthroscopic and open methods for the treatment of PCL tibial­side avulsion injuries resulted in comparably good clinical outcomes, radiological healing, and stable knees.

코골이 및 폐쇄성 수면무호흡증에서 Laser-assisted Uvulopalatoplasty와 LaserUvulopalatopharyngoplasty의 치료 성적 : 장기추적관찰후 환자 만족도 조사

김재호,이윤식,박형욱,송용진,남순열,김용재,이봉재 대한이비인후과학회 2000 대한이비인후과학회지 두경부외과학 Vol.43 No.2

단일 전력단 능동 클램프형 고주파 공진 인버터에 관한 연구

강진욱,박재욱,원재선,배영호,김동희 嶺南大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.30 No.2

This paper presents active-clamp type high frequency resonant inverter with single-stage. The proposed topology is an integrated circuit of active-clamp type high frequency resonant inverter with boost converters having the function of power factor correction. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. Hence a high power factor operation is achieved naturally. By adding active-clamp circuit to conventional class-E high frequency inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Theoretical analysis in converter part is performed with Psim 4.1 software tool and in inverter part is generally evaluated by using normalized parameter and characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter can be practically used as a power supply in the fields of induction heating applications, DC-DC converter, etc.

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.

중대산업사고 예방을 위한 종합위험관리체제(IRMS) 구축에 관한 연구

권혁면,성대현,김재현,임대식,김기영,편무욱,문일,고재욱,이영순,윤인섭 한국안전학회 2003 한국안전학회지 Vol.18 No.3

The Process Safety Management (PSM) by the Law of Industry, Safety and Health has been performed for preventing major accidents of chemical plants since 1996. In terms of preventing chemical accidents more precisely, it is essential to develop a tool for quantitative risk assessment. For this, KOSHA (Korea Occupational Safety and Health Agency) developed an Integrated Risk Management System (IRMS) . The system is designed to assimilate data on chemical plant hazards from external database, to integrate these data with location information (topographic and demographic), and to make them user-friendly accessible. The system consists of several main functions: display of five major Korean petrochemical complex layout, display of equipment layout with its information utilizing the external database, zonation of the hazard effected area with consequence analyses, the most probable accident scenario generation, accident/incident database and calculation of frequency of accident using equipment reliability database, etc. The highlight of IRMS is to provide the risk contours using GIS(Geographical Information System) technology. IRMS is intended to manage hazardous installation more systematically and effectively, to reduce the number of accident remarkably, further minimizing production loss in the plant. The system is now under application to about 500 PSM sites as well as and emergency authorities in Korea by KOSHA (Korea Occupational Safety and Health Agency)

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

최근 5년간 급성 A형 간염으로 입원한 환자들에 대한 입원 내용 분석

장재영,유병욱,조용진,오정은,홍성호,조주연 순천향대학교 의학연구소 2009 Journal of Soonchunhyang Medical Science Vol.15 No.1

Abstract Background : Due to improvements in Korea's sanitary conditions, antibody rates to the hepatitis A virus is decreasing rapidly and admission due to the disease is increasing, Patients who were admitted for hepatitis A during the last 5 years were selected and yearly differences in admission, clinical picture, medical fees, and differences according to age and gender were analyzed. Methods : Patients who were admitted to the Seoul Soonchunhyang University Hospital during the 5 year period between May of 2003 and April of 2008 and tested positive for IgM anti-HAV were selected and their medical records retrospectively analyzed. Results : 156 subjects [91 male (58%), 65 female (42%) were selected. The average age was 29.2 years (range; 21.4-37), average admission period 12.6 days (range; 12.5-1 7.7) days, and average medical fees 2,295,151 (range; 932,097-3,658,205) KRW(Korean Won), Yearly incidence rates were as follows : 10 for May, 2003 to April, 2004, 14 for May, 2004 to April, 2005, 23 for May, 2005 to April, 2006, 69 for May, 2006 to April, 2007, and 41 for May, 2007 to April, 2008, The maximum value median of AST, ALT, and bilirubin during admission was 989 IU/L, 1999 IU/L, and 5.6 mg/dL each, Each factors were all positively correlated with the patient's age. Conclusions : Recent decrease in antibody positivity of the hepatitis A virus and subsequent surge of acute hepatitis A is a cause of rising socioeconomic costs. A large scale epidemiologic research on whether HAV vaccination should be made mandatory and health insurance applied seems to be needed. Key words : Hepatitis A, Age, Medical fees, Vaccination

고전압 마이카 커패시터 설계에 관한 연구

김재욱 남서울대학교 2010 남서울대학교 논문집 Vol.16 No.1-1

본 논문은 특 고압(17 - 50 kV AC) 권선형기기의 부분방전신호 검출을 위한 80pF 에폭시-마이카 커패시터를 설계하고 시뮬레이션 하였다. 유전체를 마이카로 하고 전극을 연박으로 하여 각각 1매씩 교대로 적층하여 단위 커패시터를 병렬 연결한 병렬 커패시터 로 하였다. 요구되는 커패시턴스와 최대 내전압을 고려하여 병렬 커패시터 의 직렬연결 수를 정하고 각 병렬 커패시터 간의 절연을 위하여 격리 마이카 시트를 삽입한 후 와 사이를 직렬로 연결하였다. 고전압 마이카 커패시터의 설계 및 시뮬레이션을 위하여 HFSS(High Frequency Structure Simulator)를 사용하였다. 단위 커패시터를 병렬 연결한 커패시턴스 는 1948[pF]로 계산 결과인 1662[pF]를 만족하는 결과를 얻어낼 수 있었다. Key Words : High-voltage, Epoxy, Mica, Capacitor