• 제목/요약/키워드: Inter turn short

검색결과 24건 처리시간 0.019초

H2S Gas Sensing Properties of SnO2:CuO Thin Film Sensors Prepared by E-beam Evaporation

  • Sohn, Jae-Cheon;Kim, Sung-Eun;Kim, Zee-Won;Yu, Yun-Sik
    • Transactions on Electrical and Electronic Materials
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    • 제10권4호
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    • pp.135-139
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    • 2009
  • $H_2S$ micro-gas sensors have been developed employing $SnO_2$:CuO composite thin films. The films were prepared by e-beam evaporation of Sn and Cu metals on silicon substrates, followed by oxidation at high temperatures. Results of various studies, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that $SnO_2$ and CuO are mutually non-reactive. The CuO grains, which in turn reside in the inter-granular regions of $SnO_2$, inhibit grain growth of $SnO_2$ as well as forming a network of p-n junctions. The film showed more than a 90% relative resistance change when exposed to $H_2S$ gas at 1 ppm in air at an operating temperature of $350^{\circ}C$ and had a short response time of 8 sec.

전기 자극 청신경 복합활동전위: 변인 영향 (Electrical Compound Action Potential: Effects of different parameters)

  • 허승덕
    • 재활복지공학회논문지
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    • 제8권1호
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    • pp.9-17
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    • 2014
  • 전기 자극 청신경 복합활동전위(electrical compound action potential; ECAP)는 인공와우로 청신경을 자극하고 동시에 반응을 기록한다. 이 연구는 인공와우에서 ECAP의 효용성을 높이기 위하여 자극과 기록에 대하여 연구하고자 한다. 대상은 문헌 또는 사례 연구를 제외한 연구 논문 34 편으로 하였다. 연구는 펄스 및 자극 조건, 잡파 억제 및 기록 조건 등을 분석하였다. 효과적인 신경 발화, 안정적인 역치 확인, 신경 퇴행 방지 등을 위해서는 펄스폭과 위상 간격이 가급적 짧고, (-)위상이 앞선 양위상 펄스를 사용하였다. 자극은 펄스 간격, 자극비율, 자극 방식 등을 정하여 와우의 첨부, 중간, 기저회전으로 C-level 정도로 하였다. 잡파는 전방차폐법, 거푸집소거법으로 제거하였고, 분명한 파형을 획득하기 위해서는 전극 간격, 증폭 정도, 평균 가산 회수 등의 추가 조절이 필요하다.

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Rotor Fault Detection of Induction Motors Using Stator Current Signals and Wavelet Analysis

  • Hyeon Bae;Kim, Youn-Tae;Lee, Sang-Hyuk;Kim, Sungshin;Wang, Bo-Hyeun
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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    • pp.539-542
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    • 2003
  • A motor is the workhorse of our industry. The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. Different internal motor faults (e.g., inter-turn short circuits, broken bearings, broken rotor bars) along with external motor faults (e.g., phase failure, mechanical overload, blocked rotor) are expected to happen sooner or later. This paper introduces the fault detection technique of induction motors based upon the stator current. The fault motors have rotor bar broken or rotor unbalance defect, respectively. The stator currents are measured by the current meters and stored by the time domain. The time domain is not suitable to represent the current signals, so the frequency domain is applied to display the signals. The Fourier Transformer is used for the conversion of the signal. After the conversion of the signals, the features of the signals have to be extracted by the signal processing methods like a wavelet analysis, a spectrum analysis, etc. The discovered features are entered to the pattern classification model such as a neural network model, a polynomial neural network, a fuzzy inference model, etc. This paper describes the fault detection results that use wavelet decomposition. The wavelet analysis is very useful method for the time and frequency domain each. Also it is powerful method to detect the features in the signals.

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사회적 기술 부족과 충동성으로 인해 또래갈등이 심한 분교아동의 상담사례 (Counseling Case Study of a Child with Peer Confliction due to Lack of Social Skills and Impulsiveness)

  • 이인선
    • 초등상담연구
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    • 제5권1호
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    • pp.227-253
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    • 2006
  • It seems common for students living at a small county and islands to experience psychological conflicts and be unaccustomed in the peer society because they are not familiar with peer interaction and social skills. This is a case study of L (hereinafter called L) who was grown up in the sheltered school at a small county. L was psychologically disturbed because he couldn't get along well in the transferred school. It is the reason why he had lived in the sheltered school at a small county, so he had not enough exposure to interact with peer and social skills. Sometimes he was obstinate irrationally and when he had trouble with friends, he threw something out or went out of school and tricked juniors dangerously. The fact of disperse with families, parent's indifference, and hate of older brother made L to have ill feeling against family. He had low motivation and low self confident in learning because of short attention time and accumulated poor learning progress. In this study, he was evaluated at various area, such as, intelligent, affective, personal and inter-personal, before counselling. To evaluated the effect of the counselling, K-WISC-III, KPRC, sentence filling test, social adaptation ability test, etc, were administered right after the counselling was over and 8 weeks later. For specific information gathering and analysing, observation diary and deepen counselling were accomplished by homeroom teacher, his mother, and his peers. To correct his problematic behaviors, 13 counseling sessions were accomplished for 6 months and those counselling sessions were recorded and analysed definitely. Followings are the result of this case study. First, he was recovered from the anxiety of inter-personal interaction and he started to interact with peers. The result of sac scale score of KPRC profile was lower than before as much as average student after counseling and 8 weeks later. This reveals that the distress against interpersonal relation have settled. Especially, through the result of sentence filing test, he seemed to feel attachment to peers and be positive, active in the relation of peer. For instance, he was active in the open class lesson and interacted well with peers. It could be said that he overcame the psychological distress comparing with previous time. Second, he could apologize to his peer and juniors for his fault. His attitude were well shown in the letter from an old friend at the sheltered school, average KPRC profiling score comparing with previous counseling time, and remarkable decrease of attack scale score of teacher and peer. Third, his view toward family turn out positive. He recognized his situation that he lived apart from family and even worried about his parent's financial difficulty. Through solving the confliction with his older brother, he could acquire the feeling of family reunion. Fourth, his learning motivation and self-confidence were increased. He confirmed his future positively and he might be judged more attentive because his intelligence index was higher than before as much as average student. With the main goal of this study, verification for effectiveness of counseling. understanding and helping problematic students such as L who lives at a small county and island through investigation of their real situation and problems with the method of counseling and socio-cultural analysis is worthwhile. Identification of ideal relationship with peer is related with positive self-conception, harmonic social adaptation and development of child. It is time to investigate easy adaptive in classroom and well-organised program to acquire general social skills for sheltered school students at a small county and islands.

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