형상기억복합재료에 대한 온라인 모니터링 시스템 개발

이동화,박영철,이민래,이동화,이규창 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.1

형상기억복합재료를 제조하기 위하여 핫프레스 방법을 이용하여 최적의 제조조건을 도출하였으며 냉간압연에 의해 기지재와 강화재의 계면접합을 강화하여 강도를 증가시켰다. 이러한 방법에 의해 제조된 형상기억복합재료에 대하여 외부 하중에 의한 손상정도와 균열의 발생을 감지하여 균열 발생 및 진전을 억제하는 온라인 모니터링 시스템을 개발하고자 한다. 이를 위하여 음향방출 신호의 파라미터를 이용하여 손상에 따른 최적의 AE 파라미터를 도출하였으며 가열시스템을 이용하여 형상기억합금을 가열함으로써 형상기억합금의 수축에 의한 복합재료 내부에 균열진전을 억제시키는 시스템을 개발하였다. A hot press method was use for the optimal manufacturing condition for a shape memory alloy(SMA) composite. The bonding between the matrix and the reinforcement within the SMA composite by the hot press mothod was strengthened by cold rolling. In this study, the objective was to develop an on-line monitoring system for the prevention of the crack initiation and propagation by shape memory effect of SMA composite. Shape memory effect was used to prevent the SMA composite from cracking. For the system to be developed, an optimal AE parameter should be determined based on the degree of damage and crack initiation. When the SMA composite was heated by the plate heater attached at the composite, the propagating cracks appeared to be controlled by the compressive force of SMA.

Highly mesoporous activated carbon fibers using high density polyethylene precursor with a multi-step stabilization technique for automobile carbon canister

Jeong-Rae Ahn,Hye-Min Lee,Byung-Joo Kim 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

In this study, activated carbon fibers (ACFs) for automobile carbon canisters were produced usinghigh-density polyethylene (HDPE) fibers treated with a multistep stabilization process as the precursor. The stabilization of the HDPE fibers involved the following sequential steps: (1) electron beamirradiation, (2) mild sulfonation, and (3) dry oxidation. The stabilized fibers were carbonized at 900℃in a nitrogen atmosphere. The carbonized fibers were activated at 900℃ in a water–vapor atmospherefrom 30-60 min. The textural properties of the activated carbon fibers were determined using N2/77 Kadsorption–desorption isotherms. The specific surface area ranged from 1090 to 1980 m2/g, and the totalpore volume ranged from 0.56 to 1.11 cm3/g. The specific surface area, micropore volume, and mesoporevolume increased with increasing activation time. The fractions of micropores and mesopores were similaracross all conditions, whereas the yield decreased gradually until 50 min, and then exhibited a sharpdecline at 60 min. The butane working capacity increased as much as 56.24% as the increase in activationtime. This can be attributed to the increase in butane activity owing to the increase in micropore volume,along with a decrease in butane resistivity caused by the increase in mesopore volume at a specificdiameter.

工業敎育大學 敎育改善에 관한 硏究(Ⅲ)

宋周鎬,李昌岬,洪元杓,孟琦錫,任洪彬,李廷玟,李載元,李來烈,權五憲,金振淳,李文洙 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

This paper aims at providing a concrete plan to improve technical and vocational teacher education in the College of Industrial Education of Chungnam National University. It is intended to propose a practical four-year regular and short-term course. Also, the estimated required facilities is included in this study as well as their management. The main conclusions and recommendations are summarized as follows; 1) The numbers of students enrollment should be reduced to 220 students which is the approximate number of future demand. 2) In order to offer to the students a broader education and to cope with the increase/decrease in demand of technical and vocational teacher within a specific field, the 8 department existing at the present (Department of Architecture Engineering Education, Civil Eng. Educ., Metallurgical Eng. Educ., Mechanical Eng. .Educ., Electrical Eng. Educ., Electronic Eng. Educ., Industrial Chemistry Educ. and Industrial Technology Educ.) would be combined into 5 (Department of Construction Engineering Education, Mechanical Eng. Educ., Electrical Eng. Educ., Industrial Chemistry Educ. and Industrial Technology Educ.). 3) The short-term course program is recommened to provide additional training and education to those candidates who already have experience in technical fields to meet an occasional demand. 4) It is necessary to add the Teaching Profession Section in the administrative organization of the College.

재해사례분석을 통한 빌딩공사 재해 특성

이종빈,노민래,고성석 한국안전학회 2004 한국안전학회지 Vol.19 No.3

Recently, construction work's tendency has become a high-rise building, a complexity and a large size. According to the KOSHA data, construction work accidents have not been decreased. Looking at from the side of accident, accidents of construction industry are occupied over 1/3 among all industry accidents. Therefore, this study will analyze the accident of the building construction work from the data of KOSHA which were collected during 11 years(1992 -2002) data relating to serious accidents of the building construction work, suggest the counterplan according to the each work type in building construction work.

원전 체크밸브 진단기법 개발을 위한 음향방출기법 및 신경회로망 적용에 관한 연구

이민래,이준현,최상우,김정택,김정수 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

This work performed in support of the International Nuclear Energy Research Initiative(INERI) program, which was to develop and demonstrate advanced sensor and computational technology for on-line monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants(NPPs). The primary objective of this work is to investigate advanced condition monitoring systems based on acoustic emission detection that can provide timely detection of check valve degradation and service aging so that maintenance/replacement could be preformed prior to loss of safety function. The research is focused on the capability of AE technique to provide diagnostic information useful in determining check valve aging and degradation, check valve failures and undesirable operating modes. This work also includes the study to detect failure in check valves using neural networks.

優秀工業系 實科敎員養成을 위한 工業敎育大學 敎育課程 改善에 關한 硏究 : 工業敎育學部를 中心으로

李廷玟,任洪彬,李載元,李來然,金澤基,劉承坤 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)

This paper is studied to improve the curriculum of the College of Industrial Education of Chungnam National University, which is more helpful for the students to become a competent teacher of technical high school. The thesis includes the curriculum of general, professional, technical subjects and so on. The main conclusions are summarized as follows; 1) The current curriculum of the College of Industrial Education was formed on a wholesale manner following the basis of standard courses for some characterized engineering colleges. But the suggested is conformed to the curriculum system of CNU in credits and hours. 2) The current technical subjects are mainly based on the curriculum of college of engineering, but the newly suggested technical subjects are conformed to the curriculum of technical high school as following that some departments of engineering are founded in the College of Industrial Education. 3) In current curriculum, the ratio of reguired technical subjects to elective technical subjects is 85:15. In suggested curriculum, the ratio of it is largely changed to 45:55 for effective operation of minor cousres. And the lists of the subjects for minor courses are changed from subjects for College of Science to subjects for College of Engineering.

레이저 초음파와 Wavelet변환을 이용한 재료표면균열 평가

이민래,최상우,이준현 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.2

비파괴 평가 기술들 중의 하나인 레이저 초음파 응용 기술은 각종 구조물에 존재하는 표면결함에 의한 신호를 통해 건전성을 평가하는 기법이다. 따라서 결함의 신뢰성 높은 정량적 평가를 위해서는 결함으로부터의 레이저 초음파 신호특성에 대한 기본적 이해가 필수적이며 따라서 이를 위한 신호해석 연구가 요구된다. 본 연구에서는 레이저 유도 초음파에 의한 one-sided 기법을 이용하여 표면균열을 평가하고자 하였다. 하지만 레이저를 이용한 평가방법들은 수신된 신호의 해석이 까다로우며 또한 상당한 전문적인 지식이 요구된다. 웨이블렛 변환(wavelet transform, WT) 기법은 신호처리 분야에서 하나의 새로운 방법으로서 다양한 분야에 적용되고 있으며 특히 한 시점에 대한 주파수 분해가 가능한 신호처리 방법으로서 시간-주파수 분석에 아주 유용하게 이용되고 있다. 본 연구에서는 이러한 레이저 유도 초음파를 이용하여 재료의 표면 결함신호들에 대한 웨이블렛 변환기법을 적용하여 보다 정량적인 결함 크기를 예측하고 그 타당성을 평가하고자 하였다. Laser-generated ultrasonic technique which is one of the reliable nondestructive evaluation techniques has been applied to evaluate the integrity of structures by analyzing the characteristics of signal obtained from surface crack. Therefore, the signal analysis of the laser-generated ultrasonics is absolutely necessary for the accurate and quantitative estimation of the surface defects. In this study, one-sided measurement by laser-generated ultrasonic has been applied to evaluate the depth of the surface-breaking crack in the materials. However, since the ultrasonic waveform excited by pulse laser is very difficult to distinguish the defect signals, it is necessary to consider the signal analyses of the transient waveform. Wavelet Transform(WT) is a powerful tool for processing transient signals with temporally varying spectra that helps to resolve high and low frequency transient components effectively. In this paper, the analyses of the surface-breaking crack of the ultrasonic signal excited by pulse laser are presented by employing the WT analyses.

모노에탄올아민 전처리에 의한 양모섬유의 저온염색

하민자,이내연 충남대학교 1991 論文集 Vol.14 No.1

The dyeing properties of wool pretreated with monoethanolamine and neutralized with formic acid were investigated. The experiments were performed using Orange Ⅱ(C.I. Acid Orange 7) for various temperatures(40°, 50°, 60℃) at pH 4.7. The apparent diffusion coefficients of preteated wool were larger than untreated wool and the apparent activation energy of diffusion of pretreated and untreated wool were 19.7 K㎈/㏖, 28.3 K㎈/㏖, respectively. According to the dye absorption and dye exheastion curve, the temperature dyeing of preteated wool might be possible at 50℃ for about 1 hours.

Cone beam형 전산화 단층촬영장치를 이용한 설공의 해부학적 구조

기민우,황의환,이상래 대한구강악안면방사선학회 2004 Imaging Science in Dentistry Vol.34 No.3

Purpose : To evaluate whether cone beam computed tomography can depict the distribution, position, frequency, relative vertical dimension, and the diameter of the lingual foramen and direction of lingual bone canal. Materials and Methods : Cone beam computed tomography of mandible was performed on 25 males and 25 females with no history of any orthodontic treatments or any other dental surgeries. A statistical comparison was done on the mean values of males and females. Results : In the location and distribution of lingual foramina, median lingual foramen was found in all subjects and lateral lingual foramen in 58%. In the lateral lingual foramen, bilateral type was found in 28% and unilateral type in 30%. In the number of lingual foramina, median lingual foramen had two foramina and lateral lingual foramen had one foramen, mostly. In the relative mean vertical dimension of lingual foramina, median lingual foramen was 0.03 ±0.08, and both lateral lingual foramina was 0.20±0.04. The mean diameter of lingual foramina, median lingual foramen was 0.9mm±0.28, right lateral lingual foramen was 0.92mm±0.23, and left lateral lingual foramen was 0.88 mm±0.27. The most frequent direction of the lingual bone canals, median lingual bone canal proceeded in anteroinferior direction and lateral lingual bone canal in anterosuperolateral direction. Conclusion : Cone beam computed tomography can be helpful for surgery and implantation on the mandibular area. Radiologist should be aware of this anatomical feature and its possible implications.

工業系 中等敎員들의 資格硏修 效果

金種石,李廷玟,李來然,羅聲雄 충남대학교 공업교육연구소 1987 論文集 Vol.10 No.1

The purpose of this study was to investigate the effectiveness of inservice training in order to evaluate the current training program sponsored by the Secondary School Teacher Inservice Training Center. The contents and time of this program was implemented during Summer, 1986. The program was for the teachers to obtain the advence qualification. A total of 405 teachers were registered to the program and the questionnaire developed by the investigators administered to the participants of the program. The content of the questionnaire composed of 1) Personal data, 2) General curriculum, 3) Pedagogical subjects, 4) Subject Specialty, 5) Evaluation method, 6) The conditions and facilities for learning. The findings of this study were as follows; (1) General curriculum facilitated and encouraged the participants to inhence the national morality, comittment to teaching profession and democratic citizenship. (2) Pedagogical subjects facilitated and encouraged the participants to improve teaching skills. (3) Subject specialty area facilitated the participants to improve the knowledge of teaching subject. (4) For the evaluation methods, most participants favored objective test more for the general curriculum and pedagogical subject than subject specialty area. (5) The conditions and facilities for learning were responded unfavorable to the participants especially in computer availability and teaching method of computer.