Effect of Cooling Rate on Mechanical and Electrical Properties of Cu-TiB₂ by Turbulent In-Situ Mixing Process

Park, J.S.,Yun, J.H,Park, Young Do,Park, Yong Ho,Cho, Kyung Mok,Park, Ik Min Scitec Publications Ltd. 2007 Solid State Phenomena Vol.119 No.-

<P>A copper matrix composite reinforced with in situ TiB2 nanoparticle was successfully fabricated by tubulent in-situ mixing process. The microstructure, mechanical and electrical properties of the in situ composite were investigated. The results showed that the in situ formed TiB2 particles, in which size varying from about 50nm to 200nm, exhibited a homogenous dispersion in the copper matrix. It is shown that the interface between the nanoscale particles and the matrix was clean without a transitional layer. Because of the reinforcement, the hardness and Young’s Modulus of the composite improved with increment of cooling rate. Moreover, the in situ Cu-TiB2 composite exhibited higher electrical conductivity with increasing of cooling rate.</P>

개에서 피지선 과형성의 진단 및 치료 증례

박희서,손화영,정성목,송근호,조종기,이영원,신상태,김명철,김덕환,박성준 충남대학교 수의과대학 동물의과학연구소 2004 動物醫科學硏究誌 Vol.12 No.-

An eleven year old castrated male Maltese was presented to the Veterinary Medical Teaching Hospital of Chungnam National University. In physical examination, approximately 0.5 cm round mass was observed on tail base. This small elevated mass has also shown alopecic and firm configuration. It was differentially diagnosed as sebaceous adenoma and hyperplasia by fine needle aspiration. After surgical removal, the sample was diagnosed as sebaceous hyperplasia by histopathological examination. It has not yet shown any signs of recurrence and prognosis has teen good.

이산화질소, 암모니아 및 수분의 기상반응에 의한 이산화질소 제거 거동에 관한 연구

목영선,장경룡,박태성,김경숙,남인식 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

암모니아 첨가 저혼 플라즈마 공정이나 전자빔 공정에서 NO의 산화반응을 통해 생성되는 NO_2를 효과적으로 제거하기 위한 조건을 도출하기 위하여, 문헌의 반응속도에 기초한 반응기 모델링을 통해 NO_2 저감에 미치는 여러 가지 운전변수의 영향을 살펴보았다. 본 연구에서 운전변수로 선정한 것은 수분함량, 초기 NO_2 농도, 반응온도 그리고 암모니아 농도이며, 각각의 운전변수에 대한 적정 범위를 결정하였다. NO_2를 효율적으로 제거하기 위해서는 배기가스의 수분함량이 4-6%(v/v)이상은 되어야 하나, 수분함량을 더 증가시키는 것은 큰 이득이 없는 것으로 나타났다. 초기 NO_2 농도가 100ppm 이하로 작을 때는 원하는 제거효율을 달성에 필요한 체류시간이 급격히 증가하며, 반응온도는 낮을수록 NO_2제거에 유리한 것으로 나타났다. NO_2 저감 속도는 암모니아 농도이며, 각각의 운전변수에 대한 적정 범위를 결정하였다. NO_2를 효율적으로 제거하기 위해서는 배기가스의 수분함량이 4-6%(v/v)이상은 되어야 하나, 수분함량을 더 증가시키는 것은 큰 이득이 없는 것으로 나타났다. 초기 NO_2 농도가 100ppm 이하로 작을 때는 원하는 제거효율 달성에 필요한 체류시간이 급격히 증가하며, 반응온도는 낮을수록 NO_2 제거에 유리한 것으로 나타났다. NO_2 저감 속도는 암모니아의 농도에 크게 의존하지 않는 것으로 평가되었다. This study reports a simple reactor modeling utilizing chemical kinetic data of the gas phase reaction between nitrogen dioxide, ammonia and water vapor in order to estimate the influences of several operating variables on the removal of NO_2 which is generated from NO by the oxidation process in a non-thermal plasma reactor or an electron-beam irradiation reactor. The operating variables chosen are water vapro content, initial concentration of NO_2, reaction temperature and ammonia concentration and the appropriate ranges of such variables were suggested. The gas phase reaction for the removal of NO_2 takes place effectively at the water vapor content higher than 4-6%(v/v), but further increase in the water vapor content does not significantly enhance the removal. The residence of NO_2 is less than 100ppm. Since the removal rate of NO_2 is in inverse proportion to the reaction temperature, lower temperature is favorable to promote the reaction. The effect of ammonia concentration on the removal of NO_2 was estimated to be negligible.

作文 能力 伸張 方案 硏究

朴泳穆 弘益大學校 敎育硏究所 1994 敎育硏究論叢 Vol.- No.10

The Purpose of this study is to summarize the knowledge acquired from writing research and to draw implication for writing instruction. Recently, composition theorists are pointing out the need to consider the role of academic disciplines in writing. The use of writing in specific academic settings is usually a function of a teacher and the construct this teacher has of the writing purpose and context. the writing acroos the curriculum movement has come from a growing body of theory linking writing to learning. This theory argues that writing is ideally suited for the discovery, formulation, and expression of ideas. Academic discipline, whose instructional goals are to teach students a body of knowledge while also helping them to acquire the communication skills, thinking skills, and positive emotions of professionals in the field, emphasize on writing as a mode of learning. Composition theorists are pointing out the need to consider the role of the situation in writing. Writing does not occur in a vacum. It always occurs in some kind contexts. A piece of writing comes into existence as the result of a response to a situation that often demands immediate attention. A writing situation consists of the complex interrelations of persons, events, and objects which the writer must take into account in order to bring about a change in the sistuation. A writing situation must take into account the reader, the writer, the subject of writing, and the writer's purpose. Research on composing has exploded that the composing process has much in common with the problem solving processes people use every day. The experts in their fields are characterized by two things: a great deal of knowledge about their topics and a large repertory of powerful strategies for attacking their problems. Good Writers share these qualities. They are people who have developed better ways to entertain the problems of writing. The problem solving strategies of the experts writers can give them the enormous power of conscious choice - the power to guide, test, and alter their own problem solving process.

Coating을 시행한 뇌동맥류 파열환자의 예후

박종혁,석종식,목진호,박관,김영백,민병국,황성남,최덕영 대한신경외과학회 1995 Journal of Korean neurosurgical society Vol.24 No.6

In rare occasions in which aneurysmal neck clipping is nearly impossible, coating is employed. During the period from 1985 to 1992, 312 patients with aneurysm underwent surgery ; aneurysmal neck clipping were performed in 284 cases while coating only in 28. The reasons that coating was required were ; wide and broad neck in 13, perforators arising from the neck in 4, neck tearing during dissection in 3, very friable neck in 2, severe adhesion with surrounding structures in 3, and small aneurysm without enough room for clipping in 3. In twenty-three cases, cotton wisp and bioglue were used as coating materials. In another five cases, the aneurysmal wall was reinforced using Surgicel or Gelfoam. Patients were followed for 24 months on average of all the patients. Four had last contact Six died(4 due to rebleeding and 2 due to pneumonia). Fourteen were good and 4 were moderately disabled. There were no rebleeding incidences during first three months' follow-up after coating. We thus concluded that coating an aneurysm offers some protection from rebleeding, particularly when the rebleeding risk period is over.

사회 경제적 지위와 의식구조와의 상관 관계 : 대구지역 청소년가장과 일반고교생과의 비교분석 A comparison of Teenage Family Heads with Normal High School Students

박영목 한국복지재단 1988 동광 Vol.85 No.-

Thought, attitude, and behavior of human are always internelated one another. These must be a social and cultural product gained in the course of life. This research studied what kinds of social and environmental factors would influence the two groups: normal high school students and the teenage family heads. The survey consisted of a questionaire which was administered to 112 high school students (55 boys and 57 girls ) and to 80 teenage family heads over the age of 14 selected by Korea Children's Foundation living in Taegu. The questions of the survey were composed of 33 items. The analysis of the result of the survey shows that: 1. The monthly income of 92.9% of the teenage family heads was below 200,000 Won. Because of economic destitution, the teenage family heads seemed deprived of normal hobby life as is shown that only 31.9% of them enjoy watching television and reading books compared to the normal high school students who enjoy computer games, art, and travel (27.6%). 2. As to the health problem, 11.1% of the teenage family heads thought health was their problem while only 1.8% of the normal high school students thought health as their problem. While only 11.7% of the high school students had egony related to employment, family affair, and economy, 67.5% the teenage family heads had agony on these above matters. This indicates that the teenage family heads were severely involved in living problems and they had little concerns on their health problem. 3. Even in the teenager headed families, there was sex discrimination in oppotunity for education as shown in the rate of high school enrollment between male family heads (63%) and female family heads(57.2%). 4. In the psycho-social aspects, 34.1% of the teenage family heads judged their economic problems were due to the shortage of their effort, but 21.5% of the high school students thought that their efforts were in shortage. While 28.8% of the teenage family heads consodered social contribution or service given to society in job selection and value in human life, 35.4% of the high school students quoted economic affluence or social fame (35.4%) as their goal. 52% of the teenage family members or neighbors than that of themselves, but 27.9% of the high school students had more concern about themselves (28.4%). This shows that the high school students are generally individualism oriented but the teenage family heads are colletive and altruist. 5. In the problem of education, in spite of their desire(64.5%) to go to higher educational institutions, the teenage family heads had to give up continuing school and this must be a decisive ractors in reaching out to society. Accordingly, teenage family heads preferred to taking safe occupation such as teacher, nurse, or business firm worker(56.3%) compared with high school students who were interested in the positions available by a long-term investment such as political science, prefessor, or medical fields. This shows that the teenage family heads were reality and existence oriented rather than future concerned. It is likely that their current situation will not easily bettered.

후두와 병변 수술의 발생한 경막하 긴장성 기두증

목진호,김한식,이규춘,박용석,이영배 東國大學校醫學硏究所 1999 東國醫學 Vol.6 No.-

긴장성 기두증은 신경외과영역에서 개두수술 후에 발생할 수 있는 드문 합병증으로 특히 만성 뇌경막하 혈종 제거수술이나 좌위에서 후두와 수술을 시행한 경우에 발생할 수 있다. 따라서 개두수술 후에 신경학적 증상의 악화가 있거나 수술 후 예상경과를 취하지 않는 경우에는 긴장성 기두증의 발생 가증성을 항상 고려하여야 한다. 긴장성 기두증의 발생기전은 물병을 거꾸로 세운 것과 같은 기전(Inverted pop-bottle mechanism)으로 뇌척수액이 누수된 만큼 공기방울이 경막하강으로 올라가 빈 공간을 메우는 것이다. 이와 같은 기전으로 두개강내로 들어간 공기가 일정한 압력을 가지게 되어 주변 뇌조직을 압박하여 신경학적 장애를 초래하게 된다. 뇌전산화 단층촬영을 이용하여 쉽게 진단이 가능하며 치료는 두개골 천공을 시행하여 두개강내 공기를 배기시켜 줌으로서 가능하다. 저자들은 복와위에서 후두와 병변 수술 후에 발생한 긴장성 기두증을 뇌전산화 단층촬영을 이용하여 진단하고 전두골을 천공하여 두개강내 공기를 배기시켜 치험하였기에 문헌고찰과 함께 증례를 보고하는 바이다. 중심단어:긴장성 기두증, 후두와 수술, 경막하강, 복와위 Tension pneumocephalus is a rare complication in neurosurgical operation and should be considered whenever a patient fails to recover as expected following surgery. The possible mechanism for the entry of air into the subdural space is analogous to the entry of air into an inverted soda-pop bottle. As the fluid pours out. air bubbles reach the top of the container, Computed tomography permitted rapid diagnosis including localization of the air, thus facilitating prompt treatment. Peaking of frontal lobe. mountain appearance of frontal lobe. and air densities at the cisterns are characteristic findings of' tension pneumocephalus on brain CT scan. This condition is easily diagnosed and treated using twist-drill aspiration. The authors describe a case of subdural tension pneumocephalus complicating the early postoperative course after posterior fossa surgery in the prone position.

쓰기 영역 교육과정 설계의 원리와 절차

박영목 弘益大學校 敎育硏究所 1997 敎育硏究論叢 Vol.- No.14

The purpose of this study is to investigate the principle and procedure of systematic design of Korean writing program. Language is the most powerful tool we have for representing the world to ourselves to the world. Language is not only a mans of communication, it is basic instrument of thought, a defining feature of culture, and important mark of individual identity. Encouraging and enabling students to learn to use written language effectively is one of our society's most important tasks. The writing curriculum mainly contain purpose dimension, content dimension, and development dimension. The purpose dimension adresses the question of why students learn written communication skills. It considers the range of motives, reasons, and desired outcomes, or the ends to which direct our teaching writing. Students should use written language for a variety of purposes, such as to learn, to express ideas, to convey information, to pursuade others, to note things we observe, or to engage with others socially. The act of writing may involve several of these different purposes. The content dimension adresses what students should know and be able to do with writing curriculum. This includes knowledge of written texts and of the processes involved in creating such texts. The development dimension focuses on how learners develop competencies in the writing.

作文 硏究의 最近 動向과 展望

朴泳穆 弘益大學校 敎育硏究所 1995 敎育硏究論叢 Vol.- No.12

The purpose of this study is to trace the emergence of composition studies as one partof a more general intellectual history concerning the problems of meaning in discourse, and to summarize the trends and perspectives of composition studies. The study of rhetoric generated not only an elaborate system for investigating language practices but also theoretical questions about the relationship of language to knowledge. The system of classical rhetoric was too powerful to be limited to to the few forms of public speaaking to which it was originally applied, and the questions about language ans knowledge rasied by classical rhetoricians were never to be put to rest. After the classical rhetoric period, all forms fo discourse ans symbolic communication can be reduced within its scope. The history of rhetoric is the story of long struggle to understand the relationship between discourse and knowledge, communication and its effects, language and experience. Recent developments in composition studies as well as both critical and linguistic theories have parraled each other in fundamental ways. The 1950s were largely a period of formalism. In compositon, learning to write meant learning to avoid text errors. Formalis assumed an objectivity of text elements, contending that all important issues about text and text meaning could be adressed through analysis of text elements and their inter-relationship. Evidence concerning language processes such as writing, reading, and thinking was held to be unobjective, unreliable, and spurious. In the late 1960, formalist conceptions of composition came under attack and began to wane, and scholars began to think of writing not in terms of text or products but rather in terms of the cognitive processes of writing. This view of language as a cognitive, constructive process motivated writing scholars to reconceptualize writing as dynamic processes of constructing meaning. In this constructivist view, language orders and gives shape and meaning to experience. The meaning were said to be generated and then stored as mental representation. In the 1980s, the cognitive studies supplemented by social analysis that proved the character of interpretive and discourse communities and investigated the dialogical nature of written communication. This social reorientation of the field demanded that composition scholars reevaluate sorne pet of cognitivist assumptions that had virtually swept the field by the early 1980s. Thus writing scholars began to interprete the different genres of academic writing ain terms of didcourse communities to describe the social and historical nature of writing. They suggest that individual writers compose not in isolation but as members of communities whose discourse practices constrain the way they structure meaning. Thus the problem students face in writing could be explained by their lack opf familiarity with the forms and conventions of academic discourses.

" The Korean Journal of Chemical Engineering " 게재 논문 요약 : Processabilities & Mechanical Properties of the Biodegradable LDPE / Modified Starch Blends

Young Jin Kim,Yong Man Lee,Hyang Mok Lee,O Ok Park 한국화학공학회 1994 NICE Vol.12 No.5

N/A An investigation of the biodegradable polymers based on starch has been accomplished. Starch needs to be modified before blending with low density polyethylene(LDPE) because of its hydrophilicity. Three kinds of modification methods were applied to obtain the compatibility to starch-LDPE blends. The first one was the esterification of the hydroxyl group of starch with acetic anhydride. The second was the copolymerization of actylonitrile and styrene onto starch. The last was the esterification reaction of the hydroxyl group of starch with three kinds of ionomers. The tensile strength, % elongation, Young`s modulus, and shear viscosities of blends of the modified starch and LDPE were examined. Ionomer-treated starch showed better compatibility with LDPE to give better performances than other blends.