• Title/Summary/Keyword: Field aging

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A Study on Growth Characteristics of Water Tree in XLPE (가교폴리에틸렌의 수트리 성장특성에 관한 연구)

  • 김덕근;임장섭;김철운;류경우;김태성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.346-349
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    • 1997
  • It is well known that water treeing is one of the main cause of breakdown in underground power cables, but water tree is not easy to observe. This aging phenomenon was resulted in effect of water and electric field and so on. In this paper, Distilled water was used as water electrode to observe the water treeing in XLPE(cross-linked polyethylene). To observe easily, sample was made of pallet types so water tree was able to show by microscope. As a result, electrical tree appears at niddle electrode tip which was concentrated electric field, but water tree was shown up different types that were appealed in total area of water electrode as well as water electrode tip.

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Current development of microtip FEDs and carbon nanotube FEDs

  • Kim, Jong-Min
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.49-50
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    • 2000
  • 5.2" microtip field emission displays (FEDs) with high voltage applications are fabricated. Nano-structural analysis on microtips is performed for the reliable operation of FEDs. Chemical compositions on the apex of microtips are fully analyzed. A charging mechanism on spacers is simulated and experimentally confirmed with micro-images. A gas-aging mechanism is also studied with integration step of FEDs. The brightness of more than 300 $cd/m^2$ is achieved. In addition, as a new concept, 9" color carbon nanotube FEDs (CNT-FEDs) are introduced using well-aligned carbon nanotubes on glass substrates by paste squeeze and surface treatment techniques. A number of carbon nanotubes, $5-10/{\mu}m2$, are uniformly distributed over a large area. The turn-on fields of 1 $V/{\mu}m$ and field emission currents of 1.5 mA at 3 $V/{\mu}m$ are acquired. Different mechanisms between microtip FEDs and CNT-FEDs are discussed.

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Characteristics analysis of field aged distribution surge arresters (경년에 따른 배전용 피뢰기의 열화특성)

  • Cho, Seong-Soo;Kim, Ju-Yong;Kim, Chan-Young;Song, Il-Keun;Park, Jung-Shin
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2323-2325
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    • 1999
  • This paper presents characteristics of the aged and new 18kV surge arresters. In order to investigate aging characteristics, we measured total leakage current and resistive leakage current using specially made leakage current measurement system and also investigated $tan{\delta}$ of the arresters and microstructure of the elements. Through the investigation we found that all of the arresters does not aged for 2 years field operation.

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EFFECT OF THE ADDITION OF Ni ON GIANT MAGNETORESISTANCE OF Cu-Co AGED RIBBONS

  • Kim, I.J.;Echigoya, J.;Fukamichi, K.;Shimada, Y.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.456-460
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    • 1995
  • Giant magnetoresistance(GMR) of $Cu_{85-x}Co_{15}Ni_{x}$ melt-spu ribbons is closely correlated with the microstructure produced by the spinodal decomposition. The solid solution range is extanded by the replacement of Cu by Ni in the as-quenched state. The wavelengths obtained by subsequent isothermal aging in Cu-Co-Ni ribbons are shorter than those in Cu-Co binary ribbons, resulting in the increase of the surface-to-volume ratio. The largest MR ratio of 8 % in high field has been achieved in the $Cu_{80}Co_{15}Ni_{5}$ aged ribbon. The field dependence of MR ratio in low fields becomes larger with the Ni content.

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A Field Survey to Derive Defect Rate According to the Years of Use of Fire Doors in Apartment House (공동주택 방화문의 사용연수에 따른 불량률 도출을 위한 현장조사)

  • Kim, Yun-Seong;Kwon, Yeong-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.97-98
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    • 2022
  • The purpose of this study is to find out the failure conditions of fire doors in the process of use and prepare maintenance measures against them and find out the failure conditions and failure rates of fire doors according to the period of use of buildings. According to a survey of the failure rate and failure factor of fire doors, the failure rate of fire doors under 5 years was 3.7%, 13.4% of fire doors under 5 years and 10 years, and 14.8% of fire doors under 15 years and 27.6% of fire doors over 20 years. In particular, 15 years later, the failure rate of fire doors exceeded 20%. The main defects were found to be natural aging, holes, opening and closing failures, gaps, and failure and wear of accessories such as gaskets and door closers.

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Studies on the Deformation in the Hysteresis Loop of $Pb(Zr,Ti)O_3$ Ferroelectric Thin Films ($Pb(Zr,Ti)O_3$ 강유전체 박막 이력곡선의 변형에 관한 연구)

  • Lee, Eun-Gu;Lee, Jong-Guk;Lee, Jae-Gap;Kim, Seon-Jae
    • Korean Journal of Materials Research
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    • v.10 no.5
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    • pp.360-363
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    • 2000
  • Deformation in the hysteresis loop of $Pb(Zr,Ti)O_3$ (PZT) thin films with various Zr/Ti ratios has been studied by varying the top electrode preparation method and the annealing temperature. Pt/PZT/Pt capacitors was found to be positively poled due to dc plasma potential generated during reactive ion etch (RIE) of Rt. Internal field is formed by space charges trapped at domain boundaries. Aging phenomenon such as constriction in the middle of the hysteresis loop was observed in the PZT film with top electrode deposited by sputtering. Top electrode annealing restores the hysteresis loop by removing the space charges. As Zr/Ti ratio decrease, voltage shift increases and an-nealing temperature at which internal field disappears also increases.

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Effect and Response of Skeletal Muscle Cells on Electrical Stimulation Condition (전기자극 조건에 따른 근육 세포에 미치는 영향과 반응)

  • Seo, Hyung Woo;Shin, Hyun Young;Lee, Hyun-Ju;Tae, Ki-Sik;Kim, Minseok S.
    • Journal of Biomedical Engineering Research
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    • v.38 no.6
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    • pp.308-312
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    • 2017
  • Skeletal muscle function plays a very important role in quality of life. However, skeletal muscle causes functional decline under aging or some diseases. Exercise and muscle training are good solutions to delay sarcopenia, but there are limitations to those who are uncomfortable in exercise. For this reason, alternative interventions for muscle sarcopenia are required, and many studies proved the increase of skeletal muscle mass by electrical stimulation. In conventional studies, however, mouse skeletal muscle cells have been mostly used in experiments to identify electrical stimulation conditions while human derived cells have not been frequently utilized in these studies. Stimulation used for rehabilitation has been uniformly treated without the consideration of aging. In addition, many studies have been used with conventional petri dish usually requiring many numbers of cells, which is not appropriate for rare. Moreover, they are not usually condition uniformity of electrical field. In this study, we have developed an electrical stimulation device which consumes a small amount of cells and can form a uniform electrical field. With the system, we analyzed the skeletal muscle differentiation and Myotube thickness depending on the electrical stimulation condition.

Trend Analysis of Age Structure Ratio Change in Disaster Response Organization and Presenting the Criteria of Age Limit of Fire-fighting Field Activities -Focused on Firefighters in Seoul Metropolitan City- (재난대응조직 연령 구성비 변화 추이분석 및 구성원의 현장활동 한계연령 도출 -서울지역 현장활동 소방공무원을 중심으로-)

  • Park, Chanseok
    • Journal of the Society of Disaster Information
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    • v.10 no.3
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    • pp.466-480
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    • 2014
  • In addition to aging social problem, the problem of older age structure ratio in the fire service organization playing the leading role of the disaster response activities is also expected to be this serious situation. In the case of Seoul fire fighting organization, it is expected that the ratio of over the age 50 reaches 31% or 40% between from 10 to 15 years later from now on, but this will be a serious problem in the fire fighting personnel needing a healthy body and physical strength in the disaster situation unlike the civil servants of general staff. Therefore, the purpose of this study is to take measures that can adapt to a new disaster environment of Increasing proportion of the elderly population by presenting the criteria of age limit of fire fighting field activities to analyze the relevance of the ability to perform on-site activities and age of Seoul fire civil servants, by using three analysis criteria.

Keyword Network Analysis and Topic Modeling of News Articles Related to Artificial Intelligence and Nursing (인공지능과 간호에 관한 언론보도 기사의 키워드 네트워크 분석 및 토픽 모델링)

  • Ha, Ju-Young;Park, Hyo-Jin
    • Journal of Korean Academy of Nursing
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    • v.53 no.1
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    • pp.55-68
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    • 2023
  • Purpose: The purpose of this study was to identify the main keywords, network properties, and main topics of news articles related to artificial intelligence technology in the field of nursing. Methods: After collecting artificial intelligence-and nursing-related news articles published between January 1, 1991, and July 24, 2022, keywords were extracted via preprocessing. A total of 3,267 articles were searched, and 2,996 were used for the final analysis. Text network analysis and topic modeling were performed using NetMiner 4.4. Results: As a result of analyzing the frequency of appearance, the keywords used most frequently were education, medical robot, telecom, dementia, and the older adults living alone. Keyword network analysis revealed the following results: a density of 0.002, an average degree of 8.79, and an average distance of 2.43; the central keywords identified were 'education,' 'medical robot,' and 'fourth industry.' Five topics were derived from news articles related to artificial intelligence and nursing: 'Artificial intelligence nursing research and development in the health and medical field,' 'Education using artificial intelligence for children and youth care,' 'Nursing robot for older adults care,' 'Community care policy and artificial intelligence,' and 'Smart care technology in an aging society.' Conclusion: The use of artificial intelligence may be helpful among the local community, older adult, children, and adolescents. In particular, health management using artificial intelligence is indispensable now that we are facing a super-aging society. In the future, studies on nursing intervention and development of nursing programs using artificial intelligence should be conducted.

The Effects of Preparation for Old Age of the past on Activity of the elderly: The mediating effect of Psycho-Social resources (과거 노후준비가 노년기의 활동성에 미치는 영향 : 심리사회적 자원의 매개효과)

  • Shin, Soo-Min;Kim, Dongbae
    • Korean Journal of Social Welfare Studies
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    • v.44 no.3
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    • pp.57-83
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    • 2013
  • There has neither been enough research on how to approach the concept of active aging through an integrated view nor an examination to verify the relationship between preparation for old age and active aging in later life. Therefore, this research aims to verify that the elderly, who have prepared for their later life, affected their active aged life. In addition, by setting up self-efficacy and social support as mediator in the research model, this paper looks into the psycho-social resource mechanism of the relationship in depth. In order to verify the correlation of two variables, the Seoul welfare panel data, a mediating model structured by psycho-social resources created by Seoul welfare foundation in 2010, was used. The total sample size was a group of 1,492 elders aged over 65. When it came to our research methods, structured equation analysis was applied to verify the mediating effect and theoretical background. The results revealed that physical preparation, financial preparation, social preparation and leisure preparation directly affected their active aging level positively, thus, psycho-social resources showed a partial mediating effect between preparation for old age of the past and active aging level. The research implications are as follows. First, this research makes an effort to approach the concept of preparation for old age with an integrated perspective through making a construct by entire preparation types. Second, it will attempt to verify the relationship between preparation for old age in the past and active aging in terms of multi-dimension is meaningful. Third, this research reveals the function of psycho-social resource, self-efficacy and social support within the relationship. As far as the partial mediating effect is concerned, preparation for old age education for the middle-aged class should be modified as a decent field to enhance of the elderly.