• 제목/요약/키워드: cause of defects

검색결과 622건 처리시간 0.028초

유체성형과 결합한 다점 무금형 판재 성형기술 (Multi-Point Dieless Sheet Forming Technology Combined with Fluid forming)

  • 박종우;홍예선;양승훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2002년도 춘계학술대회 논문집
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    • pp.58-61
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    • 2002
  • A new concept of dieless sheet forming technology is proposed in this study to overcome the drawback of conventional dieless forming technology. For this purpose, dual points contact of the conventional punch system, which is a primary cause of surface defects, is replaced to single point contact using technology combined with fluid forming. It is expected that the advanced system may lead to easy displacement control of multi-punch elements, reducing surface defects, and increasing decision and forming limits. The reduced number of punch elements also saves the cost of the equipment. In addition, the new technology can be utilized for deep drawing as well as two- or three-dimensional curved surface forming, and thereby become multi-functional and multi-purpose differently from the conventional technology.

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슬리브 시공유형별 기계적 및 열적 가속열화특성 분석 연구

  • 안상현;김병걸;김상수;손홍관;박인표
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.286-286
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    • 2009
  • According to previous report, aged sleeves for old transmission lines have various defect such as biased installation or corrosion of steel sleeve. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Moreover, the defects have been limited power capacity of transmission line. This paper study on mechanical and thermal behavior of ACSR $410mm^2$ conductor and sleeve with various defect model. The conductor has been aged artificially for 50 years. The detailed results were presented in the text.

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응력집중부를 갖는 표면균열재의 균열길이 변화에 따른 피로거동 (The Fatigue Behavior by Variety of Crack Length of Surface Cracked Plate with Stress Concentration Part)

  • 남기우;김선진
    • 한국해양공학회지
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    • 제9권1호
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    • pp.83-91
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    • 1995
  • Surface defects in structural members are apt to be origins of fatigue cracks growth, which may cause serious failure of whole structures. Most structure has a part where stress concentrates such as welded joints, corner parts, etc. And then, analysis on crack growth and penetration from these defects, therefore, is one of the most important subjects for the reliability of LBB design. The present paper has performed an experimental and analysis on the fatigue crack propagation by variety in crack length of surface cracked plate with stress concentration part. The crack growth behavior can be explained quantitatively by using Newman-Raju equation and the stress partitioning method proposed by ASME B&P Code Sec. XI. The stress concentration factor $K_t$ has affected on the crack growth. The crack growth after penetration depends upon the initial front side crack length.

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건설업 근로자의 직무스트레스가 건설공사의 하자에 미치는 영향 (A Study on the effects of the Job-stress influenced to the construction defects)

  • 심민영;박해천;이경훈;조상훈
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2009년도 추계학술대회
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    • pp.483-493
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    • 2009
  • The global economic recession caused a great change of the labor environment such as restructurings and unstable employment. This facts brought about an increase in sense of rivalry, over workload, job uncertainty and lowering of self-confidence. Due to the fact that the work process and employing system in construction field is little differ from normal industries, especially, labors working in construction field are much exposed to the job stress. On this study, we survey construction-field labors and made an analysis of the gathered data through the statistic method to reveal what kind of job-stress factors influence on the defects of construction works. As the result, we investigated the truth of the induction factors which cause the job-stress in costruction field and proposed an alternative plan for an effective job-stress management which make the defect rate low.

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The ETS Factor, ETV2: a Master Regulator for Vascular Endothelial Cell Development

  • Oh, Se-Yeong;Kim, Ju Young;Park, Changwon
    • Molecules and Cells
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    • 제38권12호
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    • pp.1029-1036
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    • 2015
  • Appropriate vessel development and its coordinated function is essential for proper embryogenesis and homeostasis in the adult. Defects in vessels cause birth defects and are an important etiology of diseases such as cardiovascular disease, tumor and diabetes retinopathy. The accumulative data indicate that ETV2, an ETS transcription factor, performs a potent and indispensable function in mediating vessel development. This review discusses the recent progress of the study of ETV2 with special focus on its regulatory mechanisms and cell fate determining role in developing mouse embryos as well as somatic cells.

용융아연도금라인에서 에어나이프 형상패턴 변경에 의한 단부과도금 진단 (Diagnosis of Edge overcoating by Air Knife Pattern Modification in CGL)

  • 배용환;최홍태
    • Journal of Advanced Marine Engineering and Technology
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    • 제24권3호
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    • pp.20-28
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    • 2000
  • Air wiping technique is widely used because of easy and efficient coating control in present CGL The coating weight is controlled by nozzle header pressure. strip line speed, and the distance between strip and nozzle. Coating defects are resulted from the unbalance of these control factors and the inaccuracy of coating equipments. We investigates the main cause of coating defects, such as edge overcoating and coating deviation through various experiments. It is found that the edge overcoating is mainly come from nozzle lip type, and the coating deviation is caused by the unbalance of dynamic pressure.

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고압유도전동기의 회전자 결함요인 분석에 관한 연구 (A Study on Analysis of Defects cause for Rotor in the High Voltage Induction Motors)

  • 이은춘;변두균;채지석;변일환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2015년도 제46회 하계학술대회
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    • pp.655-656
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    • 2015
  • In this paper, diagnosis for 85 high voltage induction motors which have operated for more than 20 years in 18 wide area water supply offices were applied and the results of diagnosis were analysed. Furthermore, main factors that would be affecting rotor defects were selected and correlations between dependent variables which was magnitude for sideband frequency on current during operation and independent variables such as starting characteristic, operating time, number of operation, load factor, maker, rotation speed, capacity were analysed. It was clear that factors including starting characteristic, number of operation, maker, rotation speed caused break by correlation analysis. From this, regression equation was deduced through regression analysis. Based on suggested regression equation, it is applied usefully that we can estimate the condition of rotor without onsite diagnosis and plan the schedule of diagnosis.

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소프트웨어의 테스트 회수(回數)를 이용한 최적방출정책(最適放出政策) (Optimal Release Policy for a Software System using Number of Software Test)

  • 고현우;황의철
    • 품질경영학회지
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    • 제17권2호
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    • pp.27-35
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    • 1989
  • Software developers often allocate a significant amount of effort to software testing. But for most business-related software system it is natural to expect the continued discovery of defects after the software system is released into field. Such defects are usually very expensive to fix and have the potential to cause great damages to the users. It is important to stop testing the software and release it to the users at the correct time. In this paper, we propose the determination of the optimal number of software test oy minimizing a total expected software cost. A numerical example is used when the criterion is the expected profit. The result indicates that the proposed software release policy based on the number of software test can be a good alternative to the existing policy.

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연속용융도금라인에서 에어나이프 특성이 도금편차에 미치는 영향 (A Study on Coating Deviation Effect by Air Knife Characteristics in CGL)

  • Bae, Y.H.;Ahn, D.S.;Lee, S.H.
    • 한국정밀공학회지
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    • 제10권3호
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    • pp.57-68
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    • 1993
  • Air Wiping technique is widely used because of easy and efficient coating control in present CGL. Coaring weight is decided by nozzle header pressure, strip line speed and distance between strip and nozzle. Coating defects are results from unbalance of these factors and coating equipment calibration inaccuracy. Therefore, this study is mainly dealing with the cause of coating defects such as edge overcoating and coating deviation. The coptimum working condition is suggested by formulated coating model using collected working data. We developed two demension analysis program for air flow in nozzle and calculated dynamic pressure and air velocity with this program. The productivity and coating guality are improved by applying the result of this reserach.

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Development of a New Herbal Anti-arthritis Drug, \textrm{Joins}^{TM}$ (SKI 306X)

  • Cho, Yong-Baik
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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    • pp.7-13
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    • 2001
  • Arthritis may be broadly classified as degenerative - related to defects in cartilage and other joint constituents, often age-associated - or inflammatory disease. Inflammatory arthritis called as rheumatoid arthritis (RA) is a chronic inflammatory arthropathy and characterized by a destructive arthritis. RA encompasses infectious arthritis, arthritis caused by intra-articular deposits of crystalline material (gout), syndromes associated with genetic defects (familial Mediterranean fever), and the immune-mediated inflammatory arthropathy. Degenerative arthritis called as osteoarthritis (OA), which is most frequently occurring, causes degenerative figures of knee, waist and knuckle, and accompanies severe pain around the cartilage. Also, it may cause morning stiffness, gelling effect, tenderness, bone swelling, crepitus, and motion disorders.

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