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.

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.

랫드 배양배아에서 ginsenosides가 superoxide dismutase 유전자 발현에 미치는 영향

김재승, 이세라, 김연, 연정민, 백인정, 안병우, 김윤배, 이범준, 윤영원, 남상윤 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

본문참고

살모사 교상 후에 발생한 뇌간 경색

권석범,이병철,배재천,황성희,김대훈 대한신경과학회 1998 대한신경과학회지 Vol.16 No.4

위험도 정보를 이용한 Technical Specifications 개선을 위한 정량적 의사결정 방법론 연구

김범석,제무성 한국안전학회 2003 한국안전학회지 Vol.18 No.2

The utility and the nuclear research institutes in korea have conducted research for improving inefficient requirements in technical specifications using the results of probability risk assessments and informations with risk. However, the guidance for reviewing the improved technical specifications has not been developed. The objective of this study is to develop a decision-making framework for investigating and reviewing the technical documents associated with the changes of technical specifications. This study has developed a decision-making framework for reviewing the improvements of the RI-TS(Risk-Informed Technical Specifications). This work may contribute to enhancing both the safety and the efficiency of nuclear power plants by changing Technical Specifications proposed by the utility.

조직공정성과 조직후원인식의 관계에 관한 연구

정범구,김경재 충남대학교 경상대학부설 경영경제연구소 1997 경영논집 Vol.13 No.2

본 연구는 조직공정성과 조직후원인식의 상호관계를 알아보기 위해서 조직공정성과 조직후원인식의 개념과 이론을 정리하였고 연구모형과 가설을 통해서 실증분석결과를 제시하였다. 연구결과 조직공정성은 조직후원인식에 정적인 영향을 미치는 것으로 나타났고 조직공정성이 종속변수에 대하여 미치는 직접효과보다 조직후원인식을 매개로 하였을 때의 매개효과가 더 큰 것으로 나타났다.

고등학생들의 과학에 대한 정의적 인식과 과학 탐구능력 및 과학 학습성취도의 구조분석

이재천,김범기 한국교원대학교 과학교육연구소 1996 청람과학교육연구논총 Vol.6 No.1

The purpose of this study was to analyze relationships among science achievement, science process skills and affective perception of high school students. The affective perception was included attitude toward science and science anxiety in the study. The instruments were developed HARS and SAMS for this study. The subject was sampled 1,115 students by stratified cluster sampling method. The major findings of this study were as follows: The tendency to affective perception was investigated according to students variables. Attitude toward science was showed a negative perception on female than male, in rural area than city. Science anxiety was percepted highly on female than male, in rural area than city. Attitude toward science showed positive relations to science process skills, science achievement, but which showed negative relation to science anxiety. Science anxiety showed negative relations among science process skills, science achievement and attitude toward science. Structural relationships among affective perception, science process skills and science achievement were analyzed by effect size through the path analysis on the independent and dependent variables. By the results, it was indicated that there have significant direct effect not only affective perception influence on science achievement but also on science process skills in hypothesized model. Prediction of science achievement and science process skills were clarified to characteristics of the affective perception. Therefore, understanding about affective perception will be helpful to make the strategy of science teaching

주물사 부산물의 정제에 관한 연구

이재장,노범식,문영배 강원대학교 석재복합신소재제품연구센터 2001 석재연 논문집 Vol.6 No.-

연구에서는 주물사용 규석의 생산과정에서 발생되는 부산물인 미립 분말의 부가가치를 향상시킬 수 있는 기술개발을 통하여 자원의 절약과 재활용은 물론이고, 환경오염 문제의 해결에도 기여하고자 하였다. 성분분석 결과 입자 크기가 큰 경우에는 SiO2의 함량이 낮고 다른 불순물의 함량이 많았으며, 부산물의 경우는 SiO2의 함량이 94.37%로 비교적 낮고 Fe2O3, Al2O3 및 K2O의 함량이 상대적으로 높았다. XRD 분석 결과 석영 이외에 백운모가 상당량 포함되어 있어 품위 및 회수율 향상에 영향을 미칠 것으로 생각되어 이를 효과적으로 제거 할 수 있는 자력선발과 비중선별을 이용하였다. 자력선별 실험결과 부산물(tailing)의 경우 SiO2 품위와 산출률은 각각 98.42%와 87.35%까지 향상되었으며 Fe2O3의 함량은 0.17%이었다. 비중선별 결과 SiO2 품위와 산출률은 각각 96.08%와 91.16%까지 향상되었으며 Fe2O3의 함량은 0.30%로 자력선별의 경우보다 효율이 좋지 않았다. 부산물(tailing)을 대상으로 Attrition Mill로 알루미나 볼과 스테인레스 볼을 Grinding media로 이용하여 60min 정도 분쇄한 결과 평균입도 2~3㎛ 정도의 미립 실리카 분체를 제조할 수 있었다. Representative samples of solid molding sand wastes were obtained from Kwang-Jin Industrial Co. located in Chunchon. The molding sand wastes contains mainly fine iron particles, iron oxides and mica group minerals. Sand grains are angular because of being produced by the impact crushers. This study was carried out to develop an effective and economic purification technique for removing iron minerals by using magnetic separator and Mozley table. Results of experiment using the magnetic separator showed the production ratio of SiO2 increased up to 98.42wt.% and 87.35wt.% and the amount of content of Fe2O3 was 0.17wt.%. and those using the Mozley table separator showed SiO2 up to 96.08wt.% and Fe2O3 was 0.30wt.%, respectively. In grinding tests, silica flour of mean size 2~3㎛ was produced using attrition mill by stainless ball and alumina ball grinding about 60 minutes.

과학수업에서 교사에 의해 조성되는 심리적 학습환경측정 도구개발

이재천,김범기 한국교원대학교 과학교육연구소 1998 청람과학교육연구논총 Vol.8 No.1

이 연구는 과학수업에서 교사로부터 조성되는 심리적 학습환경을 조사하기 위한 도구개발이 목적이다. 이를 위하여 구조화된 면담지와 개방적 질문지를 이용하여 과학교사 및 학생들의 학습환경에 대한 조사를 실시하였다. 교사 38명, 학생 1,270명이 연구 대상으로 표집되었다. 문헌조사 및 우리 나라 학생들의 과학교사에 대한 반응유형 분석을 통하여 심리적 환경범주, 세부범주, 세부평가 척도 등이 결정되었다. 1, 2차 현장 검사를 통하여 교사특성, 수업행동, 지원적 행동 등의 환경범주와 9개의 세부범주가 조사되었다. 최종 개발된 PLEIS는 45문항의 학습환경평가 문항으로 내적 일관성이 높고 구성 타당도가 확인되었다. 개발된 조사도구는 교사의 효율성 평가도구나 학생들의 긍정적인 학습환경 조성을 위한 교수전략에 활용될 수 있다. 특히, 교육현장에서 과학교육을 담당하고 있는 교사들은 본 조사도구를 이용하여 학생들이 과학에 대해서 편안한 마음을 지니고 학습에 임할 수 있도록 하는 학습분위기 조성과 과학수업에 대한 학생들의 평가를 통하여 수업반성이나 수업전략에 대한 시사점을 얻을 수 있다. The purpose of this study was to develop for PLEIS(Psychological Learning Environment Instrument generated by science teachers). The procedure of validations' PLEIS is also examined. Samples of 1,274 for this study were selected from the secondary school students. It was conducted as a procedure development of the instrument with teachers' perception survey, students' perception response survey, second pilot for the measurement instrument. Findings indicate as the follows, (1) PLEIS was formed 3rd construct dimension, 9th subcategory. (2) the instrument consisting of 45-items' scale were used for psychological learning environment. (3) all item-type were applied 5-Likert Scale. (4) internal consistency of Cronbach α was 0.93.

대상포진 환자의 지연형 피부과민반응에 관한 연구

김재홍,김영태,윤기범 한양대학교 의과대학 1993 한양의대 학술지 Vol.13 No.1

To assess cell mediated immunity in herpes zoster patients, we evaluated delayed cutaneous hypersensitivity reactions by Multitest CMI kit in 120 herpes zoster patients and 40controls. Delayed cutaneous hypersensitivity reactions is quantified by a score (the sum of the diameters of induration) and a number of positive antigens at 48 hours. The results were summarized as follows: 1. In patient group, the average score were 10.8±6.42mm in men and 9.10±5.08mm in women. The average number of positive antigens were 3.38±1.38 in men and 2.58±1.41 in women (p< 0.05). 2. In control group, the average score were 16.60±4.34mm in men and 14.40±3.34mm in women. The average number of positive antigens were 3.80±0.81in men and 3.25±0.69 in women (p< 0.05). 3. The patient group had an average number of positive antigens significantly lower than that of control group (9.95±5.75mm for patients, 15.50±3.85mm for controls) (p<0.05). 4. The patient group had an average number of positive antigens significantly loxer than that of control group (2.98±1.38 for patient group, 3.25±0.75 for control group) (p<0.05). 5. Average score of patient group above 50 years of age (7.90±5.26mm) was significantly lover than that of patient group below 50 years of age (11.20±6.05mm) (p<0.05). 6. Average score of control group above 50years of age (13.09±4.20mm) was significantly lower than that of control group below 50 years of age (17.32±3.57mm) (p<0.05). 7. Average score of the patients had associated with hypertension, diabetes mellitus, hepatic diseases, were similar to that of other patients (8.10±5.82mm for hypertension, 8.97±4.98mm for diabetes mellitus, 9.25±6.32mm for hepatic diseases, 10.98±5.92mm for others). 8. Tuber was the antigen giving the strongest reaction and the highest reaction rate in both groups, while tetanus gave the lowest reaction rate in both groups. 9. The percentages of anergy were 205% in the patient group and zero% in the control group. The percentages of hypoanergy were 37.5% in the patient group and 0.5% in the control group.