• Title/Summary/Keyword: Asymmetic

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Parallel Operation Characteristics of Two Linear Induction Motors (선형 유도전동기의 병렬 운전 특성 실험)

  • Park Seung-Chan;Kim Kyung-Min
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.44-48
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    • 2005
  • In general, the parallel-connected linear induction motors(LIM) are fed by one VVVF inverter in the magnetically levitated vehicle(MAGLEV) or linear motor subway drives. The air gap length of the parallel-connected linear induction motors operating at a grade or curved sections can be different each other. The air gap difference of the two motors attached to the same module causes unequal phase currents, asymmetic thrust and attraction force generation. In this paper, parellel-connected linear induction motors are operated by one IGBT inverter under the different air gap condition so that the phase current characteristics are examined experimentally.

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The Comparison of Different of Normal Development Walking and Walking Characteristics of Children with Spastic Cerebral Palsy (보행의 정상발달 및 요소와 경직형 뇌성마비 아동의 보행 특성의 비교 연구)

  • Oh Tae-young
    • The Journal of Korean Physical Therapy
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    • v.9 no.1
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    • pp.195-204
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    • 1997
  • The Purpose of this study was to compare the different of normal development and walking characteristics of children with spastic cerebral palsy, and to guide theraputic approach for improve on walking. Key contributions from normal development of standing and walking, abnormol walking pattern of children with spastic cerebral palsy are studies. Spastic cerebral palsy includes an increased factors of problem in standing, walking : These are deformity of lowerextremities, arm used for balancing, asymmetic walking, abnormal walking patterns, build .up Treatment goal is to normal walking patterns. and to prevent secondary deformity. In this study, normal walking is very important factors in daily activities, then to recovery function of children with cerebral palsy, its need more adapted several method.

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Intercomparison of Wedge factor for Symmetric field and Asymmetric field used 6MV Linac (6 MV Linac을 이용한 Symmetric field와 Asymmetric field에서 Wedge factor의 비교 고찰)

  • Ji, Youn-Sang;Han, Jae-Jin
    • Journal of radiological science and technology
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    • v.22 no.2
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    • pp.57-60
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    • 1999
  • Therapy equipment have taken progress for Cancer make use of Radiation for the normal tissue system make much of important for shielding. In modern times independent jaw setting to used equipment as possible make use of asymmetric field. Therefore, the asymmetric field be leave out of consideration wedge factor because of with used wedge for the most of part. These experimentation find out have an effect on the dosimetry of out put compared with of the difference between the symmetric field and asymmetic field for the wedge factor.

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Silver Impregnation and Electron Microscopic Studies on the Synapse in the Visual Cortex of Rat during Postnatal Development (성장기 흰쥐 시각피질의 신경연접에 대한 도은법 및 전자현미경적 연구)

  • Lee, Hee-Lai
    • Applied Microscopy
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    • v.27 no.4
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    • pp.347-355
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    • 1997
  • These studies were performed to observe the morphological changes of synapses in the visual cortex of rat during early postnatal development. Specimens of the visual cortex were taken from rats (Sprague Dawley) at 1, 3, 7, 14 and 21 days of age, and prepared for silver impregnation and electron microscopy. The number of synapse and the length of postsynaptic thickening were increased progressively with age, especially 14 and 21 days. The number of dendritic spine was increased conspicuously on postnatal days 14-21. And asymmetic, curved and axo-spinous synapses were increased markedly at the same ages. The present findings suggest that spurt of synaptogenesis in the rat visual cortex occurs during early postnatal development, especially in second to 3rd week period and asymmetric and/or curved axo-spinous synapse is a matured form of synapse with advanced age.

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The Near Field Structure of Initially Asymmetic Jets (비대칭분류의 노즐출구영역에서의 난류유동장 해석)

  • Kim, K.H.;Shin, J.K.;Lee, H.Y.
    • Journal of ILASS-Korea
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    • v.4 no.4
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    • pp.38-45
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    • 1999
  • The near field structure of round turbulent jets with initially asymmetric velocity distribution is investigated experimentally. Experiments were carried out using a constant temperature hot-wire anemometry system to measure streamwise velocity in the jets. The measurements were undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distribution of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stress. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend at the upstream of the exit. Three pipes were used for this study: A straight pipe, 90 and 160 degree-bended pipes. Therefore, at the upstream of the pipe exit, the secondary flow through the bend and the mean streamwise velocity distribution could be controlled by changing the curvature of pipes.

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Evaluation of the Second Order Analysis of Asymmetric Unbraced Frame by using Load Amplification Factor (하중증폭계수를 적용한 비대칭 비가새 골조 2차 해석 평가)

  • Kim, Hee-Dong
    • Journal of Korean Society of Steel Construction
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    • v.22 no.1
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    • pp.87-97
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    • 2010
  • The purpose of this study was to evaluate the validity of the second-order analysis for asymmetric unbraced frame using the load amplification factor suggested by design codes. For this purpose, the first-order analysis with the B1 and B2 factors suggested by KBC 2005 and the direct analysis with the load amplification factors suggested by KBC 2009 were performed for five story - two bay and five story - four bay asymmetric unbraced steel frames. The results of the analyses were compared with the results of the second-order inelastic analysis to evaluate the validity of the suggested methods. The main parameters of the analysis were the shape of the frame, the axial load ratio of the column, the methods of analysis and the location of column. The research results show that the asymmetric shape of the frame deteriorates the validity of the factor B2 and the suggested methods. The range of error is increased in case of irregular or inclined column.

Phenomenological Study on Crystal Phase Separation in InGaN/GaN Multiple Quantum Well Structures (InGaN/GaN 다중 양자우물 구조에서의 결정상 분리 현상 연구)

  • Lee, S.J.;Kim, J.O.;Kim, C.S.;Noh, S.K.;Lim, K.Y.
    • Journal of the Korean Vacuum Society
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    • v.16 no.1
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    • pp.27-32
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    • 2007
  • We have investigated photoluminescence(PL) spectra of four $In_xGa_{1-x}N(x=0.15)/GaN$ multiple quantum well(MQW) structures with different well widths in order to study a phenomenon on crystal phase separation. The asymmetic behavior of PL spectra becomes stronger with increase of the well width from 1.5 nm to 6.0 nm, which indicates dual-peak nature. Analyzing the dual-peak fit PL spectra, we have observed that the intensity of low-energy shoulder peak rapidly becomes stronger, compared to that of high-energy peak corresponding to a transition in InGaN QW. It suggests that InGaN QW has two phases with tiny different In compositions, and that In-rich(InN-like) phase forms more and more relatively than stoichiometric InGaN(x=0.15) phase by the InN phase separation mechanism as the QW width increases. PL spectrum of 6.0-nm sample shows an additional peak at low-energy lesion(${\sim}2.0\;eV$) whose energy position is almost the same as a defect band of yellow luminescence frequently observed in GaN epilayers. It may be due to a defect resulted from In deficiency formed with development of the phase separation.