• 제목/요약/키워드: Transient Region Characteristic

검색결과 29건 처리시간 0.025초

Transient Response of Optically-Controlled Microwave Pulse through Open-Ended Microstrip Lines

  • Kim, Yong K.;Kim, Jin-Su;Park, Kyoung-Su
    • KIEE International Transactions on Electrophysics and Applications
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    • 제4C권5호
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    • pp.236-240
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    • 2004
  • In this paper we examine the reflection characteristics of dielectric microstrip lines with open-ended termination containing an optically induced plasma region, which are analyzed by the assumption that the plasma is distributed homogeneously in laser illumination. The characteristics impedances resulting from the presence of plasma are evaluated by the transmission line model. To estimate theoretically the characteristic response of identical systems in the time domain, the Fourier transformation method is evaluated. The reflection characteristics of time and frequency response in microwave systems have been calculated using an equivalent circuit model.

Study of FFF with Optically-Controlled Microwave Pulses in Non-uniform Plasma Layer

  • Wang, Xue;Seo, Dong-Ho;Kim, Yong-K.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.149-150
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    • 2009
  • In this paper we study on the semiconductor characteristic by calculating the variation of reflection function in microstrip lines, which has open-ended termination containing an optically induced plasma region. The variation of impedances resulting from the presence of plasma has evaluated with time and frequency domain. The responses have been also evaluated theoretically for changing the phase of the variation in the reflection.

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공기를 작동 유체로 하는 열다이오드의 천이 과정중 열성능에 관한 실험적 연구 (An Experimental Study on the Thermal Performance of Air filled Thermal Diode during Transfer Process)

  • 황인주;장영근;박이동;김철주
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 1996년도 추계학술발표회 논문집
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    • pp.171-175
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    • 1996
  • thermal diode is a device which allows heat to be transferred in one direction by convection due to difference of density of fluid. Vertical plate for heat collection and radiation are of utility for design of thermal diode. It was considered the transient process of air filled thermal diode with guide vane which combined rectangular and parallelogrammic shape enclosures. Gr was kept constantly on 1.60$\times$1010 and error range was $\pm$2% during the experiment. Nu was examined when inclined angle are 15$^{\circ}$and 45$^{\circ}$and, also the experiments was carried out with and without guide vane as well. Specially, The effect of guide vane was sensitive. Developed region inclined angle, which is characteristic of system.

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Transient Response of Optically-Controlled Microwave Pulse through an Open-Ended Microstrip Lines

  • Kim, Jin-S.;Kim, Yong-K.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.1187-1190
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    • 2004
  • In this paper we analyze the reflection characteristics of a dielectric microstrip line with an open-end termination containing optically induced plasma region, which are analyzed by the assumption that the plasma is distributed homogeneously in the laser illumination. The characteristics impedances resulting from the presence of plasma are evaluated the transmission line model. To estimate theoretically the characteristic response of same systems in the time domain, the Fourier transformation method is evaluated. The reflection characteristics of time response in microwave systems have been calculated.

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직립전열관에서의 유체진동에 관한 연구 (A study of flow oscillations in a upright heated pipe)

  • 박진길;진강규;오세준
    • Journal of Advanced Marine Engineering and Technology
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    • 제8권1호
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    • pp.85-99
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    • 1984
  • The stability of the two-phase flow in a heated channel is of great importance in the design and operation of the boilers and light water nuclear reactors, because it can cause flow oscillations and lead to a violation of thermal limits with resultant overheating of the channels and cladding. This paper presents a systematic evaluation to the variation effects of the basic four (4) dimensionless parameters in a homogeneous equilibrium model. The flow stability is examined on the ground of static characteristic curves. The complicated transfer function of flow dynamics which gives consideration to the transport lag of density wave is derived, and the transient flow stability is analysed by applying the Nyquist stability criterion in control engineering. The analysis results summed up as follows 1. The coolant flow becomes stable in large friction number and specific flow, while it is unstabale in small friction number and flow. 2. Large phase-change number and Froude number destabilize the two-phase flow, but small numbers stabilize it. The effect to variation of phase-change number is more dominant compared with Froude number. 3. The dynamic analysis is required to hold the sufficient safety of heated channels since only static results does not keep it. The special attention could be payed in the design and operation of heat engines, because the unstaable region exists within the stable boundary at small and middle phase-change number and Froude number.

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$Na_4P_2O_7{\cdot}10H_2O$의 축열방열시 열전달 특성에 관한 실험적 연구 (An experimental study of heat transfer with $Na_4P_2O_7{\cdot}10H_2O$ as P.C.M.)

  • 이채문;임장순
    • 태양에너지
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    • 제9권1호
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    • pp.70-77
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    • 1989
  • Sodium pyrophosphate that melting point is $79-80^{\circ}C$ have been Studied on heat storage and heat discharge. In heat storage process, sodium pyrophosphate was kept up initial temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$ which melt by heated water at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$. In heat discharge process, initial temperature of sodium pyrophosphate was maintained at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$ which varied cooling temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$. The experiment has been reached conclusions as follows. 1) Heat transfer properties of phase change material is controlled by conduction during heating and cooling process. 2) The temperature increased rapidly at initial stage and transient region increase slowly because of characteristic of latent heat. 3) The lower cooling water temperature is the less the time that get to thermal equivalent state take during discharge process. 4) The higher cooling water temperature is the less temperature difference between top and bottom in P.C.M during discharge process.

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항정신병 약물에 의한 백서 뇌에서의 c-fos 발현 : 할로페리돌과 클로자핀의 효과 비교 (c-fos Expression of Rat Brain by Antipsychotics : Contrasting Effects of Haloperidol and Clozapine)

  • 이민수;한창수;김정현;김영태;곽동일
    • 생물정신의학
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    • 제3권1호
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    • pp.115-120
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    • 1996
  • To investigate characteristic drug effects on the genetic basis, the authors administered haloperidol- the $D_2$ antagonist- and clozapine -the atypical antipsychotics with few extra- pyramidal side effects- to the rats. Then, we edobtain brain specimen from the striatum, prefrontal cortex, and cortical region and compared the degree of c-fos expression. The results are 1) haloperidol was found to produce a rapid and transient induction of dos mRNA expression in striatum as compared with cortex and prefrontal area. 2) clozapine was found to produce rapid induction of c-fos mRNA in striatum and prefrontal area. From these data, we can concluded that the mechanism of action of haloperidol is different from the mechanism of clozapine in gene expression.

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LCD 제작용 급속 열처리 시스템내의 광학 및 열전달 특성 (Optical and Heat Transfer Characteristics in a Rapid Thermal Annealing System for LCD Manufacturing Procedures)

  • 이성혁;김형준;신동훈;이준식;최영기;박승호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1370-1375
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    • 2004
  • This article investigates the heat transfer characteristics in a RTA system for LCD manufacturing and suggests a way to evaluate the quality of a poly-Si film from the thin film optics analysis. The transient and one-dimensional conductive/radiative heat transfer equation considering wave interference effect is solved to predict surface temperatures of thin films. In dealing with radiative heat transfer, a one-dimensional two-flux method is used and the ray tracing method is also utilized to account for the wave interference effects. It is assumed that each interface is assumed diffusive but the spectral radiative properties are included. It is found that the selective heating region exists for various wavelengths and consequently may contribute to heat the poly-Si film. Using the formalism of the characteristic transmission matrix, the lumped structure reflectance, transmittance, and absorptance are calculated and they are compared with experimental data of the poly-Si film during the SPC process via the FE-RTA (Field-Enhanced RTA) technology.

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The Homologous Region 3 from Bombyx mori Nucleopolyhedrovirus Enhancing the Transcriptional Activity of Drosophila hsp70 Promoter

  • Tang, Shun-Ming;Yi, Yong-Zhu;Zhou, Ya-Jing;Zhang, Zhi-Fang;Li, Yi-Ren;He, Jia-Lu
    • International Journal of Industrial Entomology and Biomaterials
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    • 제9권2호
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    • pp.235-239
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    • 2004
  • Drosophila melanogaster heat shock protein 70 gene promoter (Dhsp70p) is widely used in transgenic insect to drive exogenous gene, and the homologous region 3 from Bombyx mori nucleopolyhedrovirus (BmNPVhr3) functions as an enhancer for several promoters. To test whether BmNPVhr3 can enhance the Dhsp70ps transcriptional activity, the reporter plasmids, which contain the Dhsp70p, the reporter $\beta$-galactosidase gene with SV40 terminator and BmNPVhr3 fragment, are constructed and transfected into the insect cell lines (Bm-N cells and Sf-21 cells) by lipofectin-mediated method. The results from the transient expression assay show that BmNPVhr3 significantly increases transcriptional activity of Dhsp70p both under the normal condition and under the heat-shock treatment, although the effects are significantly different between in Bm-N cells and in sf-21 cells. The enhancing behavior of BmNPVhr3 on the Dhsp70p is in an orientation-independent manner. Meanwhile, the effects of heat-shock treatment on Dhsp70p alone or Dhsp70p/BmNPVhr3 combination present no significant difference, indicating that BmNPVhr3 only enhances the transcriptional activity of Dhsp70p, but cant alter its characteristic of the response to the heat-shock stress. The above results suggest that the Dhsp70p/BmNPVhr3 combination is more effective one to drive exogenous gene for transgene or stable cell expression system in insects.