• 제목/요약/키워드: Depletion effect

검색결과 545건 처리시간 0.025초

N2+H2 ICP 표면처리를 이용한 CVD 그래핀 도핑 연구

  • 이승환;최민섭;임영대;유원종
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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    • pp.181-182
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    • 2012
  • 본 연구에서는 반도체 기술의 핵심으로 알려있는 플라즈마 표면 처리 공정을 이용하여 인위적으로 그래핀과 기능기 반응을 통한 도핑효과를 일으켜, 전계효과(Electric Field Effect)를 인가하였을 때 그래핀 내에서 발생하는 Electron & Hole carrier 들의 accumulation & Depletion 효과에 의한 Charge Density 변화를 Graphene Field Effect Transistors (GFETs) 소자의 전기적 특성 변화를 확인하였다. 특히, 그래핀 내 Conduction of electron을 높이기 위하여, $N_2+H_2$ 가스 조합을 플라즈마 방전가스로 사용하였으며, Optical Emission Spectroscopy (OES) 및 Langmuir-probe 측정을 통하여 합성가스의 ICP 방전 상태 및 효과를 예측하였다.

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Growth Prpmotion of Taxus brevifolia Cell Suspension Culture Using Conditioned Medium

  • Kim, Myung-Hwan;Chun, Su-Mwan;Kim, Dong-Il
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제5권5호
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    • pp.350-354
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    • 2000
  • The growth promotion of a Taxus brevifolia cell suspension culture was investigated using conditioning factors. The conditioning factors produced and secreted from cultured cells usually stimulate cell division and the production of secondary metabolites. Therefore, the effective incubation time for the optimal secretion of conditioning factors was firstly determined for the promotion of cell growth. Conditioned media obtained by cultivating for 2 and 5 days showed the promotion of initial cell growth during the early cell growth period. However, the positive effect of the conditioning factors on the initial cell growth did not continue because of the depletion of the medium nutrients. Accordingly, the addition of a carbon source to the conditioned medium prolonged the positive effect on the cell growth. The addition of sucrose to the conditioned medium resulted in the maximum cell density being reached 4 days earlier compared to the control group and an increased substrate yield.

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뇌내(腦內) Norepinephrine함량변화(含量變化)와 Clonazepam의 항경련효과(抗痙攣效果)에 미치는 6-Hydroxydopamine의 영향(影響) (The Effect of 6-Hydroxydopamine on the Anticonvulsant Activity of Clonazepam and Norepinephrine in Brain)

  • 윤재순;김영주
    • 약학회지
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    • 제32권1호
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    • pp.40-49
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    • 1988
  • There is evidence that brain norepinephrine may play a role in experimentally induced seizures in animals. Thus the present experiments were undertaken in an attempt to explore the role of brain norepinephrine in anticonvulsant activity of clonazepam. 6-Hydroxydopamine was given to newborn rats and PTZ-induced seizures were tested $70{\sim}90$ days after birth and the rats were killed for determination of brain norepinephrine 8 days after the seizure test. Depletion of norepinephrine in the rat brain significantly potentiated the PTZ-induced convulsions and antagonized the effect of clonazepam on clonic seizures, tonic seizures and the number of seizures, but the latency to the seizure and the mortality has not been altered. However the 6-hydroxydopamine-induced antagonism of anticonvulsant action was surmountable by increasing the dose of clonazepam. These results show that brain norepinephrine may play an important role in seizure susceptability as well as in the anticonvulsant activity of clonazepam in rats.

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Brain Uptake and the Analgesic Effect of Oxytocin - its Usefulness as an Analgesic Agent

  • Kang, Young-Sook;Park, Ji-Hyun
    • Archives of Pharmacal Research
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    • 제23권4호
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    • pp.391-395
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    • 2000
  • To establish the usefulness of oxytocin (OT) as an analgesic for women in delivery, the pharmacokinetic parameters and blood-brain barrier (BBB) permeability of [$^3H$] OT were obtained using an intravenous injection technique or the internal carotid artery perfusion/capillary depletion (ICAP/CDM) method. Brain uptake of OT was similar to that of sucrose, plasma space marker, indicating that OT has a poor BBB permeability. Moreover, the analgesic effects of OT injected through the jugular vein on nociception were evaluated by the tail-flick method. The antinociceptive effects of OT injected at a dose of 0.2 ${m}g/kg$or 2 ${m}g/kg$ were dose-dependent. In addition, the analgesic effects of OT on the CNS were unaffected by naloxone, a m-receptor antagonist. In a similar manner to the opioid system, OT may play a modulatory role in antinociception.

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Activation of Phospholipase D in Rat Thymocytes by Sphingosine

  • Lee, Young-kyun;Choi, Myung-Un
    • Bulletin of the Korean Chemical Society
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    • 제23권10호
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    • pp.1451-1489
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    • 2002
  • Sphingosine is known to regulate a wide range of cell physiology including growth, differentiation, and apoptosis. In this study, we examined the effect of sphingosine on the phospholipase D (PLD) activity in rat thymocytes. Sphingosine potently stimulated PLD in the absence of extracellular calcium, while depletion of intracellular calcium by BAPTA/AM treatment completely blocked activation of PLD by sphingosine. Sphingosine-induced increase of the intracellular calcium concentration was confirmed using a fluorescent calcium indicator Fluo-3/AM. A phosphoinositide-specific phospholipase C inhibitor U73122 partially inhibited the stimulation of PLD by sphingosine. When mouse PLD2 gene was transfected into mouse thymoma EL4 cells, which lack intrinsic PLD activity, sphingosine could stimulate PLD2 significantly while overexpression of human PLD1 had no effect. Taken together, the sphingosine-stimulated PLD activity in rat thymocytes is dependent on the mobilization of intracellular calcium and appears to be due to the PLD2 isoform.

Effect of Ginseng Components on the Potassium Depleted Cardiomyopathic Rats and it's Mechanism of Action

  • Lee, Jong-Wook;Kim, Nak-Doo
    • Archives of Pharmacal Research
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    • 제8권2호
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    • pp.49-57
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    • 1985
  • The effect of ginseng components on the potassium depleted cardiomyopathic rat heart was investigated. In the perfused heart experiment using Langendorff apparatus, the deterioration rate of contriactile force of potassium depleted rat heart (low potassium diet group) was faster than that of normal rat heart and ginseng components showed the ability to slow the deterioration rate of potassium depleted hearts. Both sialic acid contents in carcolemmal ghost and sialyltransferase activity of 40,000 * g subcellular fraction prepared from cardiac ventricular tissue of low potassium diet group were significantly decreased compared to those of normal group. The decrease of the sialic acid content and sialyltransferase activity in sarcolemma of low potassium diet group was inhibited when ginseng was concomitantly administered. Calcium uptake of sarcoplasmic reticulum prepared from low potassium diet group was significantly greaterthan that of normal group. Ginseng extract or total saponin showed the tendency to inhibit the increase of cacium uptake.

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Buried Channel 다결정 실리콘 박막 트랜지스터의 설계 및 제작 (Design and Fabrication of Buried Channel Polycrystalline Silicon Thin Film Transistor)

  • 박철민;강지훈;유준석;한민구
    • 전자공학회논문지D
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    • 제35D권12호
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    • pp.53-58
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    • 1998
  • 다결정 실리콘 박막 트랜지스터를 이용한 회로의 성능 향상을 위하여 새로운 구조의 4-terminal buried channel poly-Si TFT(BCTFT)를 설계하고 제작하였다. BCTFT는 moderate 도핑이 된 buried channel을 이용하므로 기존의 다결정 실리콘 TFT보다 ON-전류와 전계 효과 이동도가 n-형과 p-형 소자 각각 5배와 10배 향상되었다. BCTFT는 moderate 도핑된 buried 채널과 counter 도핑된 body 사이의 junction 공핍에 의하여 캐리어의 이동이 억제 되므로 OFF-전류가 증가하지 않았다.

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GaAs/AlGaAs을 이용한 전계광학 변조기의 위상변조 효율 (Phase Modulation Efficiency of the Electrooptic Modulator using GaAs/AlGaAs)

  • 최왕엽;박화선;이종창;변영태;김선호
    • 한국광학회:학술대회논문집
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    • 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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    • pp.192-193
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    • 2002
  • In this paper we investigate the phase modulation efficiency in the electrooptic phase modulator using PPpinNN GaAs/AlGaAs W-type waveguide. The phase change is affected by the refractive index change taking place inside the depletion region. The behavior of the modulator can be understood in terms of two electric field-related and two carrier-related effects linear electrooptic, quadratic electrooptic, plasma, and bandgap shift. As a result, the phase modulation efficiency was measured about 34.6($^{\circ}$/V$.$mm) for the TE polarized light. The quadratic electrooptic coefficient R 5.82${\times}$10$\^$-15/($\textrm{cm}^2$/V$^2$) is Obtained ant the Phase efficiency Caused by the quadratic electrooptic effect is about 10 times larger than that from the conventional linear electrooptic effect.

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누설전류차단 쇼키접합 트랜지스터 전달특성 (Transistor Characteristics by the Effect of Leakage Current Cutoff of Schottky Contact)

  • 오 데레사
    • 반도체디스플레이기술학회지
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    • 제17권2호
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    • pp.32-35
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    • 2018
  • The current voltage characteristics of ZTO/SiOC were researched, and the conductivities of the ZTO films as a channel material were analyzed. The current of SiOC was abruptly decreased near 0V, and then the depletion layer was formed by the disappearance of charges in the region form -12V to +12V. SiOC with Schottky contacts near ${\sim}10^{-9}$ A had the cutoff effect of leakage currents. The conductivity of ZTOs prepared on SiOC was improved in the cutoff region of the leakage current of -12V

잔골재 중 토분이 모르타르의 기초적 특성에 미치는 영향 (The Effect of Soil on the Fundamental Properties of Mortar in Fine Aggregate)

  • 신세준;이제현;박경택;박민용;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 추계 학술논문 발표대회
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    • pp.83-84
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    • 2019
  • Recently, the supply and demand of aggregates has become difficult due to various practical constraints such as depletion of natural aggregate resources and tightening environmental regulations. As a result, aggregates such as selective crushed aggregates and river aggregates are now distributed to the construction market. In particular, among the aggregates distributed in the country, selective crushed aggregates that have been used recently are characterized by the fact that the quality of the raw material is not uniform and is based on geological characteristics. Such bad aggregates can affect the overall performance of the concrete and shorten the life of the structure. Therefore, in this study, in order to improve such problems, we want to analyze the effect of aggregate powder on mortar.

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