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.

경주지역 여고생의 초경과 체성장간의 관계

김준섭,권오구,박진석,오종수,박정현,박제식,안세한,이용환,서정호,신태섭,최영배,김덕수,이관,박수경 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

본 연구는 경주지역 1개 고등학교 3학년 여고생을 대상으로 초경 시작 전인 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레 수치와 초경 연령을 파악하여 여성의 초경이 빠를수록 체성장 속도의 변화가 있을 것이라는 가설을 기초로 두 요인간의 관련성을 파악하고자 시행되었다. 경주시 1개 여자고등학교 3학년생 총 317명에 대해 ㅊ경 나이, 초경시 심리 상태, 초경이 시작되었을 때의 상담 여부와 상담하였던 사람, 부모 신장과 초경전후의 식사 규칙성, 다이어트 경험, 수면시간, 스트레스, 음주/흡연 여부, 질병력 등에 대한 설문 조사를 시행하였고, 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레에 대한 정보는 건강기록부에서 확보하였다. 상기 대상자 중 건강기록부가 분실된 39명, 초경나이에 대해 응답하지 않았던 29명 및 결석 등으로 조사를 하지 못하였던 42명을 제외한 조사 대상자는 206명으로 선정하였다. 대상자들의 초경연령 평균값(Mean±SD)은 13.0±1.11이었고, 초등학교 4학년부터 고등학교 2학년까지의 초경 이후 신장 성장률은 감소하였으며, 초경연령이 빠른 군이 초등학교 때는 신장에 있어서 우위를 차지하나 고등학교에 오면서 신장은 비슷한 수준이 되었다. 초경후 1-2년 사이에 체중과 흉위의 증가율은 감소하였고, 초경연령이 빠른 군이 초등학교와 고등학교 사이에 체중과 흉위에서 모두 우위를 차지하였다. 본 연구의 결과는, 흔히 이차 성징의 시작 시점 혹은 사춘기의 시작 시점으로 보고있는 초경 연령이 청소년기의 성장과 밀접한 관련성이 있고, 특히 체중과 흉위의 성장 속도와 밀접한 관련성이 있음을 시사한다. To understand the onset of menarche in relation to changes in physical growth that take place during female adolescence, especially the changes in height and weight velocity. The 207 senior in one women high school of Kyongju were investigated in April 3 to 8, 2001. We collected the information, relation in the age at menarche, height & weight of parents, regularity of eating, and obesity diet, duration of sleeping, sickness & stress near age at menarche, by self-recording. The status of height, weight & chest circumference between the 4th grade of primary school and the junior of high school was collected by individual Health Record. The results were followed; The average age at menarche was 12.95±1.11 years old and the most frequent age of menarche is 13 years. After menarche, the velocity of height, weight and chest circumference were decreased. The most rapid group of menarche hold dominant position in height during elementary school. As time passed, they dont hold dominant position in height. The most rapid group of menarche get an advantage in the weight and the girth of chest after elementary school. The height of subjects is directly proportional to the height of their parents. These results suggest that the starting age at menestuation can be closely associated with physical growth and development.

북한산국립공원의 계류수질 보전 전략(I)

박재현,우보명,김우룡,안현철,조현서,추갑철,김춘식,최형태,Park, Jae-Hyeon,Woo, Bo-Myeong,Kim, Oue-Ryong,Ahn, Hyun-Chul,Cho, Hyun-Seo,Choo, Gab-Chul,Kim, Choon-Sig,Choi, Hyung-Tae 한국환경복원기술학회 2001 한국환경복원기술학회지 Vol.4 No.3

This study was conducted to investigate physicochemical property changes from July 1998 to August 2001 in Mt. Bukhansan National Park. Four water sampling points were selected to measure the quality of stream water in the northeastern part of the Mt. Bukhansan National Park. The results were summarized as follows; In spring, the average pH of stream water was below the first class of the river water quality standard, while it was normal level in summer. The average electrical conductivity was about 2.3~3.3 times higher in downstream water than in upstream water during spring and summer. The contents of anions($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) were about 1.1~7.4 and 0.4~11.4 times higher in downstream than in upstream water, respectively. These results indicate that water quality was poorer in downstream than in upstream water. We suggest that stream water in the Mt. Bukhansan National Park should be protected from impacts of snow melting mineral particles in spring season and human impacts like wastewater of point source in summer season.

절삭가공오차보상을 위한 기상측정 데이터기반 신경회로망의 응용

서태일,박균명,조명우,윤길상 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

This paper presents a methodology of machining error compensation by using Artificial Neural Network(ANN) model based on the inspection database of On-Machine -Measurement(OMM) system. First, the geometric errors of the machining center and the probing errors are significantly reduced through compensation processes. Then, we acquire machining error distributions from a specimen work piece. In order to efficiently analyze the machining errors, we define two characteristic machining error parameters. These can he modeled by using an ANN model, which allows us to determine the machining errors in the domain of considered cutting conditions. Based on this ANN model, we try to correct the tool path in order to effectively reduce the errors by using an iterative algorithm. The iterative algorithm allows us to integrate changes of the cutting conditions according to the corrected tool path. Experimentation is carried out in order to validate the approaches proposed in this paper.

공동주택 장기수선계획 시스템 개발을 위한 분석ㆍ설계단계에 관한 기초적 연구

서민구,정영한,박태근 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

Extension of building life cycle and reduction of maintenance and management relevant expenses are the top issues in the current construction market. The fields of maintenance and management are newly highlighted for the limited land and domestic economic crisis known as the 2nd IMF. We studied on the long-term maintenance plan of apartment buildings in order to analyze the defective management system of existing apartment building and secure the development-oriented management system in this study. Purposes of this study are to prevent the unwanted loss of manpower and capital resulted from the careless storage of repair and management records, extend the building life cycle and resolve the conflict caused by the uncomfortable relation with the occupants. This study is focused on presenting the potential to develop the process required for the basic analysis and development of system as the beginning stage in the process of developing the long-term maintenance plan.

자동차부품 기업의 UML기반 자재관리시스템 설계 및 구현

박정혁,서기철,문태수 한국정보시스템학회 2003 情報시스템硏究 Vol.12 No.2

One of the important applications in Enterprise Resource Planning(ERP) systems is the Manufacturing Resource Planning(MRPII) system using Bill of Material(BOM). The manufacturing resource planning determines the quantity and timing of the production or purchase of subassemblies and raw materials needed to support the Master Production Scheduling(MPS). The bill of material is the recipe, a list of the materials needed to make a product. This paper intends to suggest a component-based materials management system using Unified Modeling Language(UML), as an application system for automobile part industry. Applying component based materials management systems designed with UML methodology, we analyzed the workflow and the document on materials management process from production planning to inventory management, and implemented a prototype of efficient materials management system, as a surrogate of existing material requirement planning(MRPI) system. To produce many other assemblies for a automobile part firm, component parts are assembled into subassemblies that are joined to assemble the finished product. Through the system suggested in this study, the level of inventory has cut down and the cost of inventory management has decreased. Also, the development method using UML makes the analysis and design phase to shorten in implementation period of MRPII system. The implementation of materials management system using CBD shows the ease of use in software reuse and the interoperability with corporate internal information system. The result of applying object-oriented CBD technique is to minimize the risk of life cycle and facilitate the reuse of software as mentioned to limitation of information engineering methodology.

초등학교 과학 수행평가에 대한 교사의 인식

서승조,조태호,백남권,박강은,김성규,박장서 晋州敎育大學校 科學敎育硏究所 2001 科學敎育硏究 Vol.27 No.-

The purposes of this study are to examine how Science Performance Assesment is being well conducted in elementary schools and to check the teachers' awareness through surveying the actual condition. To achieve this purpose, the author, in this study, distributed questionnaire developed by researcher under supervision of academic advisor to the elementary school teachers in Gyeongnam province. Based on the data. the research results were mainly analyzed by the statistical method using Chi-square test. The survey was consisted of questions which was designed to perceive teachers' awareness about elementary school science performance assessment. The main findings of this study are summarized as follows', 1. Elementary teacher's are doing affirmative estimation about induction of performance assessment. 2. Most teacher are recognizing performance assessment right and teachers' understanding appeared high. 3. Material development of performance assessment is recognizing that people who have opinion which is special must develop. 4. The biggest problem of performance assessment fixing is recognizing that number of persons per class are many and amount of training courses is much also with the tribe during time. 5. It was recognizing positively whether it is in class improvement of performance assessment effect. 6. Teachers had awareness that confirm studies accomplishment degree through performance assessment, or will utilize to improvement material of teaching-learning method.

아세토니트릴 용매 중에 1-(2-Thiazolylazo)-2-naphthol의 전기화학적 거동

서무룡,박태영 慶尙大學校 1990 論文集 Vol.29 No.1

The electrochemical behaviors of l-(2-thiazolylazo)-2-naphthol(TAN) in acetonitrile(AN) solution were studied by cyclic voltammetry, controlled potential coulometry. In order to investigate the type of reducion current at each reduction step, dependence of limiting current on the scan rates and concentration of TAN have been examined. And in order to investigate the reduction mechanism of TAN in AN solution, the effect of proton donor such as water on cyclic voltammogram of TAN and the revrisbillty of each reduction step have been studied. And we measured the number of the electrons involving in each reduction step by controlled potential coulometry. The electrochemical reduction of TAN in AN solution occurs in four one-electron steps. The product of the first and third electron transfer to the dianion is followed by a chemical reaction producing a protonated species which is oxidizable to the parent compound. The product of the fourth electron transfer also produces the corresponding amine compounds.

가열로의 열적해석 및 설계인자에 관한 연구

서용석,강성규,박원희,민동호,김태국 중앙대학교 기술과학연구소 1998 기술과학연구소 논문집 Vol.28 No.-

본 연구에서는 3차원 정육면체 가열로 내의 전도-대류-복사 복합열전달 특서을 해석하였으며, 연소가스의 유입속도, 벽면의 반사율과 매체의 흡수계수 등과 같은 인자들의 변화에 따른 영향을 살펴보았다. 가열로의 벽면들은 단열되어 있고 가열로 내부로 일정한 온도의 연소가스가 유입될 때 시스템 내부의 온도는 유입 온도와 비슷하게 균일한 온도 분포를 갖는 것으로 예측할 수 있었다. 유입 속도가 증가하더라도 가열로 내부의 온도에는 거의 영향을 미치지 않았으며, 가열로는 유입되는 연소가스의 흡수계수가 증가할수록 가열로 내부의 온도는 보다 균일하게 된다. 또한, 가열로 내부 벽의 반사율이 커질수록 벽의 온도는 감소하고 또한 벽면에 작용하는 유효복사열유속은 증가함을 알 수 있었다. 이러한 해석 결과로부터 가열로 내부의 온도 분포는 매체의 흡수계수가 클수록 그리고, 벽면 반사율이 작을수록 일정하게 유지될 수 있다는 것을 알 수 있었다. 그리고 이러한 결과들을 종합하여 볼 때 가열로의 설계 시 일정한 열의 유입과 가열로를 단열시키는 것이 중요하며, 그리고 매체의 흡수 계수를 크게 하고, 그리고 벽면의 반사율을 작게 하는 것은 가열로 내부의 온도를 일정하게 유지할 수 있는 중요한 조건이 된다는 것을 알 수가 있었다.

두개강내 출혈을 동반한 불응성 특발성 혈소판감소성 자반증의 CYCLOPHOSPHAMIDE 치험 1예

서정철,양태영,최연수,박유환,김완중,허경,정원영,정춘해 朝鮮大學校 附設 醫學硏究所 1993 The Medical Journal of Chosun University Vol.18 No.1

Idiopathic thrombocytopenic purpura(ITP) is an autoimmune bleeding disorder characterized by the development of antibodies to one's own platelets, which are then destroyed by phagocytosis in the spleen and liver. Its clinical manifestations are characterized by bleeding and the most serious complication is hemorrhage into the central nervous system, but which is rarely seen below 1%. In treating IPT, the therapy of first chice is administration of adrenocorticosteroid and r-globuline. If satisfactory results are not obtained, then splenectomy is recommended. If this also proves inadequate, then administration of immunosuppressants is carried out. 16-year-old male was admitted with complaints of left hemiplegia and nasal bleeding. This case may be developed spontaneous intracerebral hemorrhage causing thrombocytopenia and was treated by steroid, r-globuline and splenectomy, but satisfactory results are not obtained. After all, the paient was successfully treated with cyclophosphamide.