鑄鐵材料의 Melt Treatment 및 Carbon Contents에 關한 硏究

최익수,김성주,문형태,노무근 삼척대학교 산업과학기술연구소 2001 産業科學技術硏究論文集 Vol.6 No.1

It is the purpose of this study to investigate the melt treatment and properties of cast iron by varifying the holding time after inoculation treatment and carbon contents. The main results obtained by investigating the microstructure and carbon contents are as follows : The number of graphite in cast iron decreases by increasing the holding time of melts after inoculation treatment, and the coarsening of graphite is achieved by increasing the length and thickness of graphite. As the carbon contents increase in cast iron, the shape and size of graphite in cast iron structure increase continuously.

치과용 자성재의 안정성 개선에 관한 연구 : I. 치과용 자성재의 전기화학적 부식에 대한 스퍼터링 도금의 효과 I. Effects of Sputtered Film Deposition on the Electrochemical Corrosion of Dental Magnetic Materials

고영무,최한철,정재헌,정효수,최성욱 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4

In order to investigate the various properties of dental magnetic materials studies on corrosion behavior, decreasing rate of magnetic flux density, amount of elements released, mean average surface roughness values and the changing of mean surface microhardness values for dental application were done. To increasing the corrosion resistance of dental magnetic materials, surfaces of Sm-Co and Nd-Fe-B based magnetic materials were plated with gold(Au), platinum(Pt), titanium(Ti), chromium(Cr) and cobalt(Co), and then electrochemical corrosion test were performed in 4 kinds of electrolyte solution(0.9% NaCl, 1% lactic acid, 0.05% HCl and modified Fusayama's artificial saliva). The results were as follows: 1. In Sm-Co and Nd-Fe-B based magnetic materials, the pitting corrosion of experimental group was higher than that of the control group, the experimental group was less corrosive than control hroup. 2. The amount of elements released from experimental group was more significantly decreased than that of control group. 3. Decreasing rate of magnetic flux density of experimental groups was significantly lower than that of control group after corrosion test. 4. The mean average surface roughness value of one(Sm-Co based magnetic materials not plated) of the control group was much increased in modified Fusayama's artificial saliva after first corrosion but that of the other(Nd-Fe-B based magnetic materials not plated) was much increased in 0.05% HCl solution. 5. The decreasing rate of surface microhardness values of experimental groups were lower than that of control group after corrosion, 6. Intergranular corrosion started first from the grain boundary of the control group and they advanced gradually to general corrosion, and the pitting corrosion occurred locally at area of existing pits in experimental group.

La_1.85Ba_0.15CuO_4-y에서 Cu 치환이 전기적 특성에 미치는 영향

서성완,최무용 성균관대학교 기초과학연구소 1994 論文集 Vol.45 No.1

산화물 고온초전도체 La_1.85Ba_0.15CuO_(4-y)에서 Cu를 전이금속 원소인 Co, Zn, Ni로 치환해 가면서 그에 따르는 열기전력과 비저항의 변화를 연구하였다. 이러한 전이금속 원소를 Cu 대신 치환했을 때 모든 경우 치환량이 증가할수록 임계온도는 급격히 감소한 반면 열기전력은 상대적으로 작은 변화를 보였다. 이것은 Zn, Co, Ni에 의한 임계온도 감소효과가 물질의 전자구조나 전도입자의 상태밀도 변화에 의한 것이 아님을 의미한다. 치환된 전이금속 원소들이 물질의 자기적 성질에 영향을 주는 가능성을 고려해 보았다. Thermopower and resistivity of La_1.85CuO_(4-y) with 3d transition metal atoms(Co, Zn, Ni) substituting for Cu were studied systematically as functions of the doping concentration. In all cases examined, T_ε decreases as the dopant concentration increases, but the thermopower shows little change in quantity. These experimental results indicate that the supression of superconductivity by transition metal atoms substitution in the material has not to do with change of the carrier concentration in the material. It is known that high-T_ε superconductivity has a close relation to antiferromagnetic ordering in CuO_2 plane. In this respect we take into consideration of the possibility that these 3d atoms may influence mangetic properties of the material.

아침형과 저녁형 사람에서 야간의 졸리움, 수행 및 체온의 비교

윤진상,국승희,신일선,신만식,최영,이무석,이형영 大韓睡眠-精神生理學會 1994 수면·정신생리 Vol.1 No.1

LAS含有都市下水의 塔式生物膜-活性汚泥混合工程에 依한 處理

李武康,崔基園,林成眞 慶星大學校 1990 論文集 Vol.11 No.3

When the synthetic wastewater including surfactant(LAS) is treated by a series TF-AS system, the results are obtained as follows; 1) It takes approximately 30 days from beginning operation to stabilize effluent concentration of each reactors under LAS conc. condition of 20,200 mg/ℓ. The above test results show that the COD removal rate is 85%, 65% in the TF reactor and 80%, 70% in the AS reactor. Therefore tatal COD removal rate is abtained 97%, 90% in the TF-AS reactors. 2) In order to obtain COD removal rate 70% above from TF reactor, the max. conditions are needed hydraulic loading 3.75ℓ/㎡ COD loading 2.55g/㎡ㆍd, LAS conc. 100 ㎎/ℓ. 3) When hydraulic loading is changed in the treatment of synthetic wastewater (LAS 20㎎/ℓ), the results are came out; Specific constant of media, n is 0.23 and Specific constant of wastewater, k'is 1.38 and the optimum parameter of the design in the TF reactors, k, k₃ is 2.813, 85.87. 4) COD removal rate of a series TF-AS system is obtained 90% over under the condition of the LAS concentration range(20㎎/ℓ-200㎎/ℓ)and also it is founded out that the more LAS concentration is added, the lower COD removal rate becomes. This makes as conclude the surfactant(LAS) causes microbial growth to be hindered by foam covered over biological film.

자기장 속에서 2차원 조셉슨 접합 배열의 상전이

황성진,김지연,최무용 성균관대학교 기초과학연구소 1998 論文集 Vol.49 No.-

We have studied the phase transition of a Josephson-junction array in a magnetic field with the frustration index f = 1/5. The results of our experimental study were found to be quite different from those of the simulation work by Y. H. Li and S. Teitel which show two-step variations of the resistance with the temperature and the dc current and the first-order nature of a phase transition. The experiment revealed one-step variation of the resistance with the temperature above the critical temperature. Thermal hysteresis, an indication of a first-order phase transition, was not observed in the resistance measurements. The resistance was also found to increase in one step with the dc current and to exhibit no hysteresis when the current direction is reversed. Origin of the discrepancy between the results of the experiment and the simulation is discussed.

SGCI 材料의 Casting 및 磨滅强度에 關한 硏究

김성주,문형태,최익수,노무근 三陟大學校 産業科學技術硏究所 2003 産業科學技術硏究論文集 Vol.8 No.2

In order to collect the basic data for the production of nodular cast iron requiring wear resistance. the mechanical nature such as structure analysis, hardness, and tensile strength were performed on cast sample by changing residual Mg concentration of cast iron at the range of 0∼0.052% and also the wear characteristics were examined through wear test by changing abrasion speed and final load. As a result, the following conclusions were drawn. The wear amount rapidly accelerates to the maximum abrasion sped of 2.3m/sec in a sample without Fe-Si-Mg alloy processing(residual Mg amount; 0%) by increasing the abrasion speed from 1.3m/sec to 2.3m/sec. As the Mg residual Mg contents increases, the ratio of nodular increases while hardness of a sample accelerates and the wear amount decreases. The maximum point moved to the high speed side in a sample with 0.043% residual Mg contents and the wear amount showed the maximum in 3.5m/sec of abrasion speed while a sample with 0.052% residual Mg contents showed the mechanical destruction wear to 4.3m/sec abrasion speed. The more residual Mg contents are in 0.6-l.1m/sec low speed range of abrasion speed, the more wear amount was resulted while the less residual Mg contents were. the less wear amount showed. Oxidation wear occurs at 4.5m/sec of traveling velocity. Since the wear of matrix structure occurs after wear of oxidized substance in friction caused by oxidized substance, the wear amount shows less than 2.3mg/sec traveling velocity. Therefore, as the residual Mg contents increase, the wear amount decreases. Although the wear amount is large since the traveling distance of destruction wear lasts very long. the residual Mg contents are small and the oxidation wear area becomes long in a sample with low hardness. Since the mechanical destruction wear occurs when the traveling &stances reaches to the end, the wear amount results in very small. The scratches appeared due to abrasive wear in mechanical destruction wear with 2.3/sec abrasion speed while it did not show in oxidation wear although the severe wear occurred. The sectional melting appeared in 5.4m/sec of high speed friction since the temperature of contact point increased more than 1000℃. Scratches are less in the area with low load and if load increase, shoving occurs in wear grooves. In the maximum load, the severe cracking phenomenon can be observed.

고등균류의 CYTKINE 분비 및 세포증식에 미치는 영향

배만종,최청,박무희,이재성 경산대학교 생명자원개발연구소 1998 생명자원과 산업 Vol.2 No.-

담자균 유래의 신규 생리활성 물질의 탐색의 일환으로 상황버섯과 버들송이의 균사체로부터 세포내단백다당류와 세퐁외단백다당류로 분리 및 정제된 시료를 가지고 세포증식, IL-2 alc IL-4 생성의 경향에 대한 실험을 행한 결과는 다음과 같다. 1. DNA 합성과 MTT에 의한 세포증식의 결과에서는, 상황버섯과 버들송이 세포배양외액에서 추출·분리된 땅류가 균사체에서 보다 비장세포에 대한 세포활성이 높은 것으로 났다. 2. IL-2 생성 결과에서는 상황과 버들송이 균사체 및 세포외액으로부터 추출된 다당류의 농도가 10∼300㎍/mL의 범위에서 IL-2 생성이 증가되었으며, 균사체 배양외액으로부터 분리된 다당류에서 높으로 것으로 나타났다. 3. IL-4 생성의 결과는 상황버섯과 버들송이로부터 추출된 세포내 및 세포외 단백다당류가 대조군에 비행서 높은 것으로 나타났다. The polysaccharide, intracellurar and extracellular, extracts from the liquid culture of the Phellinius igniarius and the Agrocybe cylindracea were purifide. This study was conducted to investigated which were measured the proliferative response to mitogens of splenocyte and production of IL-2 and IL-4. The results obtained from the experiment as follows : The proliferation of splenocyte was increased mosteffectively when the extracellua polysaccharide extracted from the Phellinius igniarius and the Agrocybe cylindracea were administrated to the mice. And the extractcellular polysaccharide extract from the Phellinius igniarius was proliferation activity increased according to culture time. The IL-2 secreased, a marker increased when 48hrs. culture with the extracellula polysaccharide extracted from the Phellinius igniarius and the Agrocybe culindracea(10∼100㎍/mL). And there was significantly the extracellula polysacchride extracted from the Phellinius then the extracellula polysaccharide extracted from the Agrocybe cylindracea. IL-4 production was significantly increased compared with the control group.

연구논문 : 중학교 과학교사들의 수업 실행 전문성 개발을 위한 교사교육 요구

최영 ( Young Choi ),이무상 ( Mu Sang Lee ),송명섭 ( Myung Seub Song ) 경북대학교 과학교육연구소 2010 科學敎育硏究誌 Vol.34 No.2

본 연구는 중학교 과학교사의 수업 실행 전문성의 개발을 위한 교사교육에 대한 요구를 조사하는데 그 목적이 있다. 최영 등의 틀(2010)을 보완하여 중학교 과학교사의 수업실행 전문성의 개발에 대한 교사교육의 요구를 조사하는 설문지를 제작하였다. 과학수업 전문성 6요소, 36관점에 대한 발달과 학습 수준, 교사교육의 필요도와 우선 요구도를 조사하였다. 대구지역 중학교 과학교사 203명의 수업 실행 전문성의 발달 수준과 학습 수준은 2.45와 3.12이었다. 발달 수준과 학습 수준 향상을 위한 교사교육의 필요도는 3.45, 3.16이었고, 교사교육의 우선 요구도가 가장 높은 요소는 `수업 계획`이었고 관점은 각각 `개인차를 고려한 계획`과 `학습 활동 계획`이었다. 교사교육의 필요도와 우선 요구도는 교사의 유형에 따라 유의미한 차이를 보였으며, 특히 경력이 적은 교사들과 지구과학 전공 교사들의 필요도와 우선 요구도가 높았다. 이상과 같은 교사교육에 대한 과학교사들의 요구는 수업 실행 전문성의 요소와 관점별로 발달 수준과 학습 수준을 향상시키는데 적합한 교사교육 프로그램 개발에 도움을 줄 것이라고 기대한다. The purpose of this study is to survey the need of in-service education for the professional development of middle school science teachers` teaching practice. The questionnaire was modified by Young Choi`s framework(2010) to survey the level of the progression in the professional development and learning, the degree of in-service education necessity, and the degree of priority of need. The questionnaire was administered to 203 middle school science teachers in Daegu. The mean level of the progression in the professional development and learning were 2.45 and 3.15. The degrees of in-service education necessity to improve level of the progression in the professional development and learning was 3.45, and 3.16. The element and aspect highest degree of priority of need were `element 1. planning coherent sequences of lessons` and `aspect 1-4. planning difference among individuals`, `aspect 1-2. planning learning activity`. The degree of in-service education necessity and the degree of priority of need was a significant difference according to almost all of the teachers` characteristics.

감잎(Diospyros kaki folium)의 Polyphenol 화합물군이 면역기능에 미치는 영향

배만종,성태수,최청,안봉전,박무희 경산대학교 생명자원개발연구소 1999 생명자원과 산업 Vol.3 No.-

한국산 감잎(Diospyros kaki folium)으로부터 polyphenol 화합물을 분리하여, 감잎의 기능성 식품으로서의 근거를 제시하고자, 면역기능의 활성화에 관한 실험을 행한 결과 다음과 같은 결과를 얻었다. 감잎의 폴리페놀 화합물이 면역기능에 미치는 영향에 관한 실험에서는 감잎으로부터 분리된 폴리페놀 화합물 Ⅰ, Ⅱ 및 Ⅲ에 비하여 시료를 투여한 군에서 항체생산이 증가되었으며, 특히 폴리페놀 화합물 Ⅱ와 Ⅲ에서 높은 유의성을 나타내었다. Rosette 형성의 결과에서도 감잎의 폴리페놀 화합물 Ⅱ와 Ⅲ을 투여한 군에서 분리된 비장과 복강 상재성 마크로파지에서 rosette 형성능이 높은 것으로 나타났다. Candida에 대한 시료의 탐식능을 관찰한 결과, 대조군에 비하여 fraction Ⅰ은 70%, Ⅱ는 76.8% 및 Ⅲ은 93%의 탐식능의 효과를 나타내었다. 또한, 면역기능을 담당하는 기관인 비장에 관한 세포증식능을 실험한 결과 대조군에 비하여 시료를 투여한 모든 군에서 비장세포가 증가하였으며, 시료의 농도가 증가할수록 세포증식도 증가되는 경향을 나타내었다. This study was conducted to investigate immuno functional activity of the ployphenol fractions isolated from persimmom leaves(Diospyros kaki folum). In the experiment of rosette forming cell, the results showed that all the polyphenol fractions enhanced the cell count compared with the control group. Especially polyphenol fraction Ⅱ and Ⅲ showed highly significant effect. The phagocytic activity of peritoneal macrophage on mice was significantly increased by the polyphenol fractions of the persimmon leaves compared with that of the control group. The gagocytic activity of polyphenol fraction Ⅰ, Ⅱ and Ⅲ oagainst the C. parapsilosis was 26.4%, 72% and 82.3% respectively. The pagocytic activity of the same fractions against the C. albicans was 70%, 76.8% and 93% respectively.