ATM을 기반으로 한 공군 방공 통신망 개선에 관한 연구

이영근 國防大學院 2000 국내석사

교사특성에 따른 초등학생의 체육수업 만족도에 관한 연구

이영근 서울시립대학교 2011 국내석사

ABSTRACT A Study on The Elementary School Students′Satisfaction of The Physical Education based On Teachers′Characteristics Lee Young-Keun Department of Physical Education Graduate School of Education of the University of Seoul This study is aimed to offer necessary information in designing and operating the physical education of elementary school through the study of elementary school students'satisfaction of physical education based on teachers'characteristics(gender, educational career, yes or no physical education major, yes or no physical education teacher, physical job training time, yes or no of coaching school sports club). In order to achieve this study objective, the questionnaire was carried out targeting 50 teachers and 300 students in the 5th and 6th grade of elementary school within Seongbuk-gu,Seoul. The collected data was used SPSS statistical program for windows. In order to understand the general characteristics in the study subjects, the frequency analysis was calculated, in order to examine whether there was difference in satisfaction with physical education based on teachers'characteristics, one-way ANOVA was carried out. As a result of analysis, the following conclusions were obtained. First, according to analyzing the satisfaction of physical education based on teachers'gender, the boy students had the high satisfaction but there was no significant difference. The boy students had the high satisfaction in the levels of education interest, but there was no significant difference in the levels of skill understand, fitness improvement, education pride, education participation. Second, according to analyzing the satisfaction of physical education based on teachers'educational career, the teachers'educational career had significant difference. the teachers'educational career was the higher, the satisfaction of physical education was the higher. When the teachers'educational career was more than 20 years, both boy and girl students'satisfaction of physical education was the highest. And when the teachers'educational career was 11~19 years, students'satisfaction of physical education was secondly highest. The satisfaction of physical education based on teachers'educational career; the levels of skill understand, fitness improvement, education pride, education interest, education participation had statistical significant difference. Third, according to analyzing the satisfaction of physical education based on whether or not teachers'physical education major, the satisfaction of a major was the higher than non-major in physical education, but the difference was not statistically significant. Fourth, according to analyzing the satisfaction of physical education based on whether or not physical education teachers, the satisfaction of homeroom teachers, but the difference was not statistically significant. Fifth, according to analyzing the satisfaction of physical education based on teachers'physical job training time, it was the highest when the physical job training time was 31~59 hours, and it was the secondly highest when the time was 60 hours over. But the satisfaction of physical education based on teachers'physical job training time was not statistically significant. Sixth, according to analyzing the satisfaction of physical education based on whether or not teachers'coaching school sports club, the satisfaction of not coaching school sports club was the higher than coaching school sports club, but the difference was not statistically significant. Seeing the above conclusions, when the physical education teachers are placed, it is considerated for teachers'educational career to improve the elementary school students'satisfaction of physical education. And it is improved for physical job training system to give the students with satisfaction practically but satisfaction of only teachers. Key Words : teachers'characteristics, the physical education of the elementary school students, satisfaction 국 문 초 록 교사 특성에 따른 초등학생의 체육수업 만족도에 관한 연구 서울시립대학교 교육대학원 체육교육전공 이 영 근 본 연구는 교사의 특성(성별, 교육경력, 체육교육 전공여부, 체육교과전담 경험여부, 체육과 직무연수 이수시간, 학교스포츠클럽 지도여부)에 따른 초등학생의 체육수업 만족도에 관한 연구를 통해 초등학교 체육수업을 설계, 운영하는데 필요한 정보를 제공하는 것이 목적이다. 이러한 연구목적을 달성하기 위하여 서울특별시 성북구에 소재한 4개 초등학교 5, 6학년 교사 50명과 학생 300명을 대상으로 설문조사를 실시하였다. 회수된 자료는 Windows용 SPSS 통계 프로그램을 이용하였다. 연구대상자의 일반적 특성을 파악하기 위해 빈도분석을 실시하였고, 교사의 특성에 따른 초등학생들의 체육수업 만족도가 유의한 차이가 있는지 알아보기 위해 일원 변량분석(One-way ANOVA)을 실시하여 다음과 같은 결론을 얻었다. 첫째, 교사의 성별에 따른 체육수업 만족도를 살펴보면, 남자가 더 높게 나타났으나 그 차이가 유의하지 않았다. 수업흥미도의 경우에는 남자가 여자보다 높게 나타났으나 기능이해도, 체력향상도, 수업자신감, 수업참여도는 통계적으로 유의한 차이가 없었다. 둘째, 교사의 교육경력에 따른 체육수업 만족도를 살펴보면, 교육경력 20년 이상이 가장 높게 나타났으며, 11~19년이 다음으로 높게 나타났으며 그 차이가 통계적으로 유의하여 교사의 교육경력이 높아질수록 만족도가 높음을 알 수 있다. 교사의 교육경력에 따른 체육수업 만족도 즉, 기능이해도, 체력향상도, 수업자신감, 수업흥미도, 수업참여도는 통계적으로 유의한 차이가 있었다. 셋째, 교사의 체육교육 전공여부에 따른 체육수업 만족도를 살펴보면, 체육교육을 전공한 교사의 만족도가 전공하지 않은 교사의 만족도보다 높게 나타났지만 그 차이가 통계적으로 유의하지 않았다. 넷째, 교사의 체육전담교사 경험여부에 따른 체육수업 만족도를 살펴보면, 만족도 전체의 경우 체육전담교사 경험이 없는 교사의 만족도가 경험이 있는 교사의 만족도보다 높게 나타났으나 통계적으로 그 차이가 유의하지 않았다. 다섯째, 교사의 직무연수 이수시간에 따른 체육수업 만족도를 살펴보면, 31~59시간이 가장 높게 나타났으며, 60시간 이상이 다음으로 높게 나타났으나 직무연수 이수시간에 따른 만족도 차이는 통계적으로 유의하지 않은 것으로 나타났다. 여섯째, 교사의 학교스포츠클럽 지도 경험여부에 따른 체육수업 만족도를 살펴보면 학교스포츠클럽 지도를 하지 않은 교사의 만족도가 클럽지도를 한 경험이 있는 교사의 만족도보다 높게 나타났으나 그 차이가 통계적으로 유의하지 않았다. 이상의 결과에서 볼 때, 초등학생의 체육수업 만족도를 높이기 위해서는 체육교과 전담교사 배치 시 교사의 교육경력을 고려하여 배치해야 한다. 또한 체육과 직무연수 제도가 교사들만의 만족을 위한 연수가 아닌 실질적으로 학생들에게 만족감을 줄 수 있는 연수가 되도록 개선되어야 한다. 주요어 : 교사특성, 초등학생 체육수업, 만족도

Gradient 演算字를 이용한 胸部放射線 映像의 改善에 관한 硏究

이영근 東亞大學校 大學院 1990 국내석사

In this paper, Gradient operators such as sobel and Roberts operators, not only enhance image edges but also tend to enhance noise. We found that sobel operator subjectively produced much better results than did the Roberts operators for the same image. By applying pill box, Gaussian, or median filtering prior to applying a gradient operator, noise was reduced. The resulting improved visualization can be particularly helpful for objects that can be difficult to visualize without processing such as lung nodules.

韓國租稅行政의 理念性 評價와 그 發展方向에 관한 硏究

이영근 慶星大學校 大學院 1994 국내박사

The purpose of this study is to present an accurate picture of Korean Tax Administration on the basis of the tax values and principles to be maximized in tax administration and then to propose a way to improve them. The tax administration in Korea today has a tendency toward authoritative, buraucratic, unilateral and directive implementations rather than for public services. Henceforth from 1980, we had to change the goal of our tax administration from simple Tax-Increasing to More of Public Services oriented which are enough to help and assist the nation to attain the goal of Self-Compliance. The tax administration should become the "Services" for the nation, that is to help and assist taxpayers to follow the tax laws. This study tries to suggest the idea on how to administer the democratic and cooperative tax-administration and -techniques on the basis of the tax administrative ideologies(the value to be maximized in Korean Tar Administration) In this respect, this study is constructed to answer the follows. (1) Does the present definition of tax and tax administration which are using today sutable to the democratic society? What is the Democratic Tax Administration? (2) What kind of values and principles has been dominated Tax Administration of Korea until now? (3) What is the normative values and principles to be maximized in Tax Administration of Korea, and now how are they realizing in Tax Administration? (4) What is the ideas how to improve the tax administration and to enhance the desirable administrative values and ideologies. This study also has analyzed and put it order the past and present charsteristics of Korean Tax Administration and summarized such fundmental denotes on it such as objective, function, organization of tax administration and tax policy. As an analytical frame to assess present Ideologies of Korean Tax Administration, this study has suggested the future oriented and desirable Ideology Model which is congenial to Democratic Tax Administration. This Model has invoked Co-productivity Model in the service delivery by Whitaker. In the Model, it is suggested the mission of future-oriented Tax Administration. The mission is to explore ways and means to further raise co-productivity in Public Service Delivery. To maximize co-productivity in the tax administration process, it is to encourage and achieve the highest possible degree of voluntary compliance with the tax laws and regulations and to maintain the highest degree of public confidence in the effectiveness and efficiency of the service. And what is more important mission should be to encourage and achieve the highest possible degree of fairness and equality of the tax structure and administration as well as openness and participation in the tax administration process. This study has also surveyed to assess the picture of Korean Tax Administration, based on the variables presented in the Ideology Model. The Certified Tax Accountants as a tax specialists was picked up through random sampling. The findings of the empirical study are as follows. First, the degree of the Legality in the Korean Tax Administration is more or less higher than other ideologies, such as efficiency, fairness and responsiveness of Tax Administration. Second, the degree of effectiveness is the most higher ideology. that is because since the 1960s, our government has emphasized securing revenues(Tax-Increasing) to propel economic development. Third, the degree of fairness or equality which means distributional justice and an equitable sharing of Tax Burden is lacking in both the sector of tax structure and the sphere of tax administration. Fourth, the biggist problemetic value and principle in the Korean Tax Administration is the responsiveness to the need of tax payers. It was assessed by the indicators such as the degree of openness in various administrative information, the degree of accessbility to administrative materials, and the degree of participation in the tax policy making and implementation process. To maximize co-productivity in tax administration, value and principles, such as efficiency, effectiveness, legality, equality and responsiveness should be improved concurrently. To improve such ideologies, we should alter the tax administration policy suitable to existing circumstances, subdevide and re-deligate the power and authorities to the national, regional and district offices and organization internally. Plan, program and workprogram should be decided by appropriate officials and organizations, and should be decided accordance with what could really be considered fair to the public. And also the legality should be emphasized to be kept both the Office of National Tax Administration and tax payers. To improve efficiency and economy in Korean Tax Administration, scientific management and Mass Data Processing System should be introduced. Tax-relevent organizations incuding the Office of National Tax Administration should be functionally reorganized from the present work-oriented organization to client-oriented organization. Ways on how to improve equality or fairness in Tax Administration has been presented as follows. - Tax reform to equitable tax burdens - Change to approriate ratio between the direct tax system and indirect tax system - Rational management of Tax-Reduction System - Adoption to Tax Expenditure Budget Sysyem - Development of how to prevent tax evasion and noncompliance To improve tax-payer's responsiveness and democratic procedure, the appellate system should be changed to the practical and effective system to prevent infringement of tax-payer's right. Furthermore, the authoritative, arrogant and impolite attitude of tax officials should be improved and replaced with a new spirit of serving, assisting and guiding taxpayers, and make them to enjoy their everyday life without any stress on their property.

다양한 정밀도를 갖는 저전력 MAC 연산기 설계

이영근 한양대학교 대학원 2008 국내석사

휴대용 전자 장치들이 점점 더 DSP(Digital Signal Processing) 능력을 요구하고 있는 추세이며, DSP 응용 분야에서 전력 소모를 줄이는 것이 시간 지연이나 크기를 줄이는 문제 등에 비해서 더 중요한 요소로 부각되고 있다. 그렇기 때문에 회로를 설계함에 있어서 정확한 동작에 영향을 주지 않는 범위에서는 전력 소모를 줄이기 위하여 약간의 오차는 허용하는 것이 추세이다. FIR(Finite Impulse Response) 필터와 DCT(Discrete Cosine Transformation)과 같은 많은 DSP 응용 분야는 계수를 곱함으로써 결과를 도출한다. 그러므로 계수 곱셈을 최적화시키는 것이 회로의 전체 성능을 향상시키는 결과를 가져다준다. 계수가 2의 거듭 제곱 꼴인 경우, 시프트(shift)를 이용하여 곱셈 연산을 대체할 수 있다. ARM 프로세서 경우, 배럴 시프터(barrel shifter)는 계수가 2의 거듭 제곱 꼴인 경우, 빠른 곱셈 처리를 위하여 중앙연산처리 장치의 보조 장치로 동작한다. 예를 들어, 4를 곱하는 것을 왼쪽으로 2만큼 시프트하는 연산으로 대체할 수 있다. 본 논문에서는 2개 이상의 배럴 시프터를 사용함으로써 이 생각을 확장한다. 또한 이런 설계로 인하에 효과적으로 곱셈기를 사용하지 않고 곱셈 연산을 하는 회로를 만들어 냈다. 본 논문에서 2개 또는 3개의 시프터를 사용함으로써 계수들을 표현할 수 있는 범위를 넓힐 수 있었다. 이렇게 표현된 계수들을 바탕으로 FIR 또는 DCT 동작을 거의 오차가 없게 실행하였다. 게다가 다양한 정밀도(Variable Precision) 기법을 적용함으로써, 제안된 구조들은 기존의 구조들과 동일한 결과를 얻으면서도 전력 소모, 회로 크기 등의 성능 면에서 큰 향상을 보였다. 결과를 살펴보면, 최상의 회로 구조로 제안한 3개의 배럴 시프터와 다양한 정밀도를 가지는 구조가 연산에 대한 오차가 거의 없으면서도 전력 소모가 곱셈기로 이루어진 구조에 비해 56% 감소한다. 다양한 정밀도의 효과만 보더라도 25%의 성능 향상을 보였다. 이러한 결과들이 본 논문에서 제안된 구조는 전력 소모를 줄이는데 효과가 크다는 것을 증명해 주었다. As more and more portable devices require DSP capabilities, reducing or area when running DSP applications on mobile devices. Therefore, the design constraint that computation results should be 100% accurate is sometimes relaxed in order to reduce power consumption as long as the error bound is tolerable. Many DSP applications such as FIR filtering and DCT (discrete cosine transformation) require multiplications with constants. Therefore, optimizing the performance of the constant multiplication is highly desirable to improve the overall performance. It is well-known that shifting can replace a constant multiplication if the constant is a power of 2. In case of ARM processors, a barrel shifter is employed as part of the main ALU to implement faster multiplication with a constant when the constant is a power of 2. In this thesis, we extend this idea in such a way that by employing more than 2 barrel shifters we can design highly efficient constant multipliers. We have found that by using 2 or 3 shifters, we can generate a large set of constants, and using these constants we can execute a typical set of FIR or DCT applications with none or little errors. Furthermore, with variable precision support, we can carry out a fairly large class of DSP applications with high computational efficiency. Compared with conventional multipliers, we could achieve up to 56% of power saving while having negligible computational errors.

都市設計 目標體系와 視知覺的 制御要素의 相關性 分析

이영근 忠南大學校 大學院 2001 국내박사

The purpose of this study is to analyze the result and problem of urban design as comparing urban design status following regulation substance by urban design guidelines and it's application. To research of this study, five representative new towns as Bundang in Seongnam, Peyongchon in Anyang, Sanbon in Gunpo, Dunsan in Daejeon, Haeundae in Busan are selected. These cities are commonly developed around the early 1990s in Korea. This study is consisted of three parts as theoretical study, general case study, and specific case study. The first part of this study reviews theoretical backgorund on the urban design guidelines, urban design regulations and control elements. The second part shows the result of comparative analysis between the control substance and the implementation of development in urban design. Main contents of analysis contain boundary of applications, presentational method of regulations, types of regulation, degree of regulatin, type of incentive, exceptional items, similarity of regulation content, and degree of observance for regulation. Through the above main parts, the problems of urban design can be categorized in four types. The first type is related on the degree of regulation; it contains shared-wall, roof, building direction, screen wall, screen shutter, and finishing method of wall surface. The second is the regulation standard, which contains floor area ratio, building height, land use, color, parking, and vehicular entrance. The third is management in usage, which contains private signs, open space of building front, open space of building-to-building, pedestrian path, arcade, and vehicular path. The fourth is the implementation of control elements, which contains harmony of existed building, root garden, and fence. The last part of this study analyzes the inter-relationship between visual objectives of urban design and control elements. Visual characterstics which related on urban design objectives are obtained as continuity, identity, amenity, activity, and publicity. Control elements, which is to support visual characteristics are as below: ·Control element for continuity: shared-wall development, height, building limitation, building line, open space of building front, roof, and arcade ·Control elements for identity: shared-wall development, Building height, Building line, Building direction, and Roof ·Control element for amenity: Open space of building front, shield landscape, public landscape, roof garden, and pedestrian path ·Control element for activity: Building direction, open space of building front, pedestrian path, arcade, and public landscape ·Control element for publicity: Open space of building front, public open space, and public landscape From the above research and analysis, we can conclude that a control element covers not only a specific single goal but also various others. Based on the survey of actual development status in detail, The supporting effect of a control element for the goal does not appear similarly. On the center of above mentined control elements, it analyzes the development characteristics in the degree of supporting for the goal. As a conclusion, this study proposes the basic ways of improvement and suggestions. *A thesis submitted to the committee of Graduate School, Chungnam National University in partial fulfillment of the requirements for the degree of Doctor of Engineering Conferred in February 2001.

鐵骨과 鐵筋콘크리트로 構成된 複合構造보 連結部의 應力傳達에 관한 實驗的 硏究

이영근 釜慶大學校 大學院 2001 국내석사

관절염 치료에 사용되고 있는 식물 추출물의 항염증 작용에 관한 연구

李榮根 전북대학교 대학원 2010 국내박사

ABSTRACT Introduction: Among the various plants that exist in nature, some plant extracts have been used in areas, such as Chinese medicine, to treat arthritis. The extracts of Ostericum koreanum, Curcumae rhizoma, Aralia continentalis, Achyanthes japonica, Paeonia lactiflora and Anemarrbena pbodeloides’s are known to be effective in treating arthritis in the arms. In this study, the antioxidant and antimicrobial effects of these extracts are evaluated for associated inflammation with pathogenic bacteria Methods : This paper presents research into the effects of these extracts as an anti-inflammatory reaction(inhibition of nitric oxide (NO) product) in lipopolysaccharide (LPS)-induced RAW 264.7 cells. The elements are extracted from the plant root with a solution of hot water and 95% ethanol. 1. Cytotoxicity of RAW 264.7 cells To investigate the toxicity in RAW 264.7 cells of the elements extracted from various plants, different concentrations of 0, 10, 20, 40, 60, 80 and 100 μg/ml are used. After 24 hours the data is collected and examined with MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-dipheyltetrazolium bromide, a tetrazole) assay. MTT assay was carried out as described by Mosmann( 1983), and Wilson (2000). 2. Inhibitory effects of NO production Inhibitory effects of NO production on plant extracts were used LPS-induced RAW 264.7 cells. Cells were treated with various concentration (0, 10, 20, 40, 60, 80 and 100 μg/ml), and 1 ㎍/ml of LPS for 24 hr. NO production measured by the Griess reagent system as described in material and methods described by Yoon et al., (2007). Control sample indicates the LPS-stimulated cells. Statistically significant value compared with control group using SPSS 12.0 in term of t-test. 3. Antioxidative activity effects DPPH (⍺-⍺-Diphenyl-β-picrylhydrazyl) radical scavenging activity of plant extracts were carried out as previously described by Blois (1958). 4. Anti-microbial activity effects on pathogenic bacteria In this study, gram positive bacteria, Staphylococcus aureus KCCM 11593 and Staphylococcus pyrogenes ATCC 19615, and gram negative bacteria, Escherichia coli KCCM 1123, Pseudomonas aeruginosa ATCC 27853 and Salmonella typhimurium ATCC 11862 were used in this work. Antimicrobial activities effects of pathogenic bacteria were carried out by the methods of Lee (1999). Results : The results of cytotoxicity of RAW 264.7 cells, anti-inflammatory activities, antioxidative activity effects and antimicrobial activity effects on pathogenic bacteria of plant extracts used for treatment of arthritis is given as follows. 1. Cytotoxicity of RAW 264.7 cells The density examination of the elements of all plant extracts obtained by hot water provided good results that there were no toxic cells in any of the plant extracts. However, O. koreanum, A. continentalis, and A. pbodeloides’s extracts did not appear to be cytotoxic, when extracted with 95% ethanol. However, C. rhizome appeared an 11.0% cell toxicity in density samples of 100 μg/ml. A. japonica has a 10.7% cell toxicity in 60 μg/ml, 13.1% in 80 μg/ml, and 13.9% in 100 μg/ml. P. lactiflora has an 8.4% cell toxicity in 80 μg/ml, and 16.4% in 100 μg/ml. A mixed 1:1 extract of P. lactiflora and A. pbodeloides has a 6.5% cell toxicity in 20 μg/ml, 21.7% in 40 μg/ml, 3.71% in 60 μg/ml. 2. Inhibitory effects of NO production For each of the plant extracts, NO product inhibition rate was measured for comparison to the control group. The O. koreanum extracted by hot water and 95% ethanol showed NO product inhibition rate increases as the density rate increased. However, in hot water extract, it has appeared 16.0% in 80 ㎍/ml, but decreased in 100 ㎍/ml sample to 13.0%. The C. rhizoma extracted by hot water and 95% ethanol showed NO product inhibition rate increases as the density rate increased. But, in hot water extract, it has a reduced result of 9.2%, as compared to 80 ㎍/ml in 100 ㎍/ml with 5.6%. The A. continentalis extracted by hot water and 95% ethanol showed NO product inhibition rate increases as the density rate increased. The A. japonica extracted by hot water has a 3.0% NO product inhibition rate in 10 ㎍/ml density, 4.0% in 20 ㎍/ml, 6.0% in 40 ㎍/ml, and 9.1% in 60 ㎍/ml. The NO product inhibition rate was 14.3.0% in 80 ㎍/ml, but has significantly decreased to -3.0% in 100 ㎍/ml. The A. japonica extracted by 95% ethanol had NO product inhibition rate of 3.0% in 10 ㎍/ml density, 4.0% in 20 ㎍/ml, and 15.6% in 40 ㎍/ml, It has 50% in 60 ㎍/ml, 80 ㎍/ml and the NO product inhibition rate was 26.0% in 100 ㎍/ml. The P. lactiflora extracted by hot water has NO product inhibition rates of 7.3% in 10 ㎍/ml density, 10.4% in 20 ㎍/ml, 10.8% in 40 ㎍/ml, and 13.0% in 60 ㎍/ml, 14.7% in 80 ㎍/ml. But, it has a reduced result of 5.2%, as compared to 80 ㎍/ml in 100 ㎍/ml with 9.5%. The P. lactiflora extracted by 95% ethanol showed NO product inhibition rate increases as density rates increased. The A. pbodeloides extracted by hot water and 95% ethanol had NO product inhibition rate increases along with the density rate. A mixed 1:1 of P. lactiflora and A. pbodeloides extracted by hot water, had a NO product inhibition rate of 8.6% in 10 ㎍/ml density, 10.8% in 20 ㎍/ml, 19.1% in 40 ㎍/ml, 18.6% in 60 ㎍/ml, 16.5% in 80 ㎍/ml and 10.4% in 100 ㎍/ml. It show different results, as compared to extracts that were not mixed together. A mixed 1:1 combination of P. lactiflora and A. pbodeloides, which was extracted by 95% ethanol, produced NO product inhibition rate increases, relative to the density rate. 3. Antioxidative activity effects This section describes the antioxidative activity for the plant extracts, which were extracted by hot water. Experimental results show 81.97% in A. continentalis, 80.33% in P. lactiflora, 79.79% in O. koreanum, 79.22% in A. pbodeloides, and 77.45% in the hybrid combination of P. lactiflora and A. pbodeloides. It is very similar to results in the control group where the BHA was 82.9%, and the BHT was 83.1%. C. rhizoma has a 58.24%, and A. japonica has 36.16%, which are low rates in comparison to the control group. This section describes the antioxidative activity for the plant extracts, which were extracted by 95% ethanol. Experimental data showed 81.03 % in O. koreanum, 76.75% in A. pbodeloides, 76.61% in P. lactiflora, 76.56% in mixed P. lactiflora and A. pbodeloides, and 72.44% in A. continentalis. This is a very similar rate, as compared to the control group. A. japonica has 41.50% and C. rhizoma has 39.20%, which are very low rates, as compared to the control group. 4. Anti-microbial activity effects on pathogenic bacteria In the case of O. koreanum, for extracts using hot water, S. aureus bacteria started to appear as anti-microbial activity in 700 ㎍/ml, and it has 35.9% anti-microbial activity in 1,500 ㎍/ml. S. pyrogenes bacteria has 48.0% anti-microbial activity in 1,500 ㎍/ml. Other bacteria do not have any anti-microbial activity. In the case of O. koreanum, extracts using 95% ethanol, S. aureus bacteria has 93.3% anti-microbial activity in 700 ㎍/ml, S. pyrogenes bacteria has 99.1% anti-microbial activity in 700 ㎍/ml. In the case of C. rhizoma, extracted by hot water, S. pyrogenes bacteria has 18.2% anti-microbial activity in 1,500 ㎍/ml, and there is no anti-microbial activity in other bacteria. In the case of C. rhizoma extracted by 95% ethanol, S. aureus bacteria has 95%, and P. aeruginosa bacteria has 100% anti-microbial activity in 1,500 ㎍/ml. In other bacteria, S. pyrogenes bacteria has 27.3%, E. coli bacteria has 51.39%, and S. typhimurium bacteria has 86.6% in 1500 ㎍/ml. In case of A. continentalis extracted by hot water, S. pyrogenes bacteria has 87.9% anti-microbial activity in 700 ㎍/ml, 96.8% in 1,500 ㎍/ml. But E. coli bacteria has 4.3%, and P. aeruginosa bacteria has 18.2% anti-microbial activity in 1,500 ㎍/ml. In other bacteria, there isn’t any anti-microbial activity. In A. continentalis extracted by 95% ethanol, S. aureus bacteria has 97.0%, and S. typhimurium bacteria has 88.0% in 100 ㎍/ml. S. pyrogenes has 60.6%, E. coli has 8.2%, and P. aeruginosa has 30.1% in 1,500 ㎍/ml. In A. japonica, S. pyrogenes bacteria has 27.9% in hot water extraction and 1,500 ㎍/ml, and 48.7% in 95% ethanol and 1,500 ㎍/ml. There is no anti-microbial activity in other bacteria. In the case of P. lactiflora extracted by hot water, S. pyrogenes bacteria has 90.9% anti-microbial activity in 700 ㎍/ml, 91.7% in 1,500 ㎍/ml, and no anti-microbial activity in other bacteria. In P. lactiflora extracted by 95% ethanol, S. aureus bateria has 87.0% in 1,500 ㎍/ml, S. pyrogenes has 84.7% in 300 ㎍/ml, and 100% in 1,500 ㎍/ml. E. coli has 36.5% in 1,500 ㎍/ml, P. aeruginosa has 32.6% in 1,500 ㎍/ml, and S. typhimurium bacteria doesn’t have any anti-microbial activity in 1,500 ㎍/ml. In A. pbodeloides extracted by hot water, S. pyrogenes bacteria has 43.0% anti-microbial activity in 1,500 ㎍/ml and no anti-microbial activity in other bacteria. In A. pbodeloides extracted by 95% ethanol, S. aureus bateria has 13.4% in 1,500 ㎍/ml and S. pyrogenes has 77.1% in 700 ㎍/ml, 89.0% in 1,500 ㎍/ml. Other bacteria don’t have any anti-microbial activity. In case of the 1:1 mixture of P. lactiflora and A. pbodeloides extracted by hot water, S. pyrogenes bacteria has 14.2% anti-microbial activity in only 1,500 ㎍/ml, with no anti-microbial activity in other bacteria. In a mixture of P. lactiflora and A. pbodeloides extracted by 95% ethanol, S. aureus has 41.6%, S. pyrogenes has 92.2%, and E. coli has 7.8% in 1,500 ㎍/ml. There was no anti-microbial activity in other bacteria.

연료전지의 산소환원반응을 위한 질소 도핑된 탄소나노섬유 기반 촉매 연구

이영근 서울과학기술대학교 2018 국내석사

산소환원반응은 차세대 에너지 저장 및 변환 소자의 중요한 양극 반응이며, 특히 높은 에너지 밀도를 갖는 연료전지와 같은 소자에서 이용되고 있다. 산소환원반응은 연료전지의 음극에서 일어나는 반응과 비교하여 상대적으로 느리고 복잡한 반응이기 때문에 산소환원반응을 효과적으로 발생시킬 수 있는 합리적인 전기화학 촉매 설계가 필요한 실정이다. 일반적으로 느리고 복잡한 산소환원반응을 향상시킬 수 있는 촉매로는 백금 기반의 귀금속 촉매가 가장 많이 사용되고 있다. 하지만, 백금 기반의 귀금속 촉매의 경우 매장량의 한계, 비싼 비용 및 높은 과전압 손실등과 같은 치명적인 문제점들을 갖고 있다. 따라서, 백금 기반의 촉매를 대체하기 위하여 비백금 기반의 촉매로써 질소 도핑된 탄소 소재가 많은 관심을 받고 있다. 탄소 소재로는 그래핀, 흑연, 탄소나노튜브 및 탄소나노섬유가 산소환원반응용 촉매의 후보로 각광받고 있으며, 이 중 탄소나노섬유는 1차원 구조의 나노섬유가 네트워크로 연결되어 있어 전자 이동 효율을 향상 시킬 수 있다. 탄소나노섬유는 물리적/화학적 안정성이 우수하며 넓은 비표면적 (> 300 m2 g-1) 및 높은 전기전도도 (102 S cm-1)를 보유하고 있다. 질소 도핑은 탄소 원자의 극성을 양전하를 갖도록 도우며, 이에 따라 산소 흡착력을 향상시켜 산소환원반응을 향상시킬 수 있다. 본 연구에서는 연료전지 및 금속공기전지의 산소환원반응을 향상시킬 수 있는 비백금계 촉매로써 질소 도핑된 탄소나노섬유 기반의 전기화학적 촉매를 제조하였다. 첫 번째로 산소 흡착력을 향상시키는 탄화철을 질소 도핑된 탄소나노섬유 내부에 도입하기 위하여 전구체 담지법을 진행하였다. 전구체 담지법은 탄소나노섬유 내부에 최적의 탄화철 담지량을 조절하기 위하여 철 전구체의 양을 0.5 wt%, 1 wt% 및 2 wt%로 진행하였다. 준비된 샘플 중 철 전구체를 1 wt% 사용한 샘플이 -0.19 V의 반응시작 전위, -0.30 V의 반파 전위 및 3.77의 전자 이동 수로 향상된 산소환원반응 활성도를 보였다. 이러한 향상된 전기화학적 특성은 산소 흡착력을 증가시키는 탄화철이 탄소나노섬유 내부에 고르게 분산되었고, 높은 비율의 pyridinic-N은 전기화학적 촉매 활성을 위한 탄소의 전자 공여 특성을 증가시켰기 때문이다. 또한, 전기화학적 안정성을 평가하였을 때, ~8 mV의 가장 적은 반파전위 감소 값을 보이는데, 이는 질소 도핑된 탄소나노섬유가 산소 흡착력을 향상시키는 탄화철의 부식을 보호하였기 때문이다. 두 번째로 질소 도핑된 탄소나노섬유에 산소환원반응 활성 면적을 증가시키기 위하여 다공성 구조를 도입하였고, 산소 흡착력을 향상시키기 위하여 불소 및 철원자를 추가적으로 도입하였다. 질소, 불소 및 철 도핑된 다공성 탄소나노섬유는 ~0.89 V의 반응시작전위, ~0.81 V의 반파전위, 0.6 V에서 -4.76 mA cm-1의 전류밀도 및 4-전자 환원반응으로 우수한 산소환원반응이 관찰되었다. 특히, 상용백금촉매와 비교하여 ~11 mV의 반응시작전위, ~10 mV의 반파전위 및 ~0.06 mA cm-2의 전류밀도 차이가 관찰되었다. 이러한 향상된 산소환원반응 활성도는 다공성 구조를 통한 산소환원반응 활성 면적의 증가, 철 원자와 결합된 질소의 거대고리, 불소 원자의 도입으로 인한 pyrridinic-N과 pyrrolic-N의 높은 비율 및 불소 도핑 중 산소환원반응이 가장 활발한 이온성 C-F 결합의 높은 비율에 기인한다. 또한 질소, 불소 및 철 도핑된 다공성 탄소나노섬유는 ~9 mV의 반파전위 감소 값으로 높은 장기 안정성을 보이며, 메탄올-크로스오버 내구성 또한 매우 우수하다. 이는 철 원자와 결합된 질소 거대고리가 전기화학 안정성에 향상을 도움을 주었고, 질소 도핑된 탄소 기반의 전기화학 촉매는 메탄올과 반응하지 않기 때문이다. 따라서, 본 논문에서 소개한 비백금계 촉매의 연구는 앞으로 사용할 연료전지 양극 촉매 적용에 도움이 될 것이라고 믿는다.

측방이동 대책공법(SCP)의 영향범위 산정에 관한 해석적 연구

이영근 창원대학교 2010 국내석사

In this study, cohesion of soft ground, soft ground depth and embankment height varying conditions, such as the impact of each condition after the calculation of the range, SCP was performed to evaluate the applicability of the method. Reinforcing effects of scope, and permit lateral movement of SCP 2D and 3D analysis of the program were calculated by the displacement ratio, the result follows. The height and depth of soft soil embankment with increasing and decreasing the cohesion tends to be affected were long range, SCP method applied by the finite element analysis Cu = 1.0tf/m2, embankment height is 3.0m depth of soft soil can be applied in a less than 5.0m, and Cu = 3.0tf/m2, embankment height, the soft soil depth is 3.0m 12.0m, Cu = 3.0tf/m2, embankment height is 5.0m less than 7.0m depth of soft soil can be applied in was. And Cu = 5.0tf/m2, embankment height is 3.0m below 15.0m depth rouge anti Floor, Cu = 3.0tf/m2, embankment height of 5.0m 12.0m depth below the soft soil, Cu = 5.0tf/m2, If the depth of soft soil embankment height of 7.0m and below 5.0m was applicable.