• 제목/요약/키워드: transport ability

검색결과 264건 처리시간 0.026초

Efficient Electron Transfer in CdSe-py-SWNTs FETs

  • Jeong, So-Hee;Shim, H.C.;Han, Chang-Soo
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.63-63
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    • 2010
  • Ability to transport extracted carriers from NQDs is essential for the development of most NQD based applications. Strategies to facilitate carrier transport while preserving NQDs' optical characteristics include: 1) Fabricating neat films of NQDs with modified surfaces either by adapting series of ligands with certain limitations or by applying physical processes such as heat annealing 2) Coupling of NQDs to one-dimensional nanostructures such as single walled carbon nanotubes (SWNTs) or various types of nanowires. NQD-nanowire hybrid nanostructures are expected to facilitate selective wavelength absorption, charge transfer to 1-D nanostructures, and efficient carrier transport. Even with the vast interests in using NQD-SWNT hybrid materials in optoelectric applications, still, no reports so far have clearly elucidated the optoelectric behavior when they were assembled on the FET mainly because the complexity involving in both components in their preparation and characterization. We have monitored the optical properties of both components (NQDs, SWNTs) from the synthesis, to the assembly, and to the device. More importantly, by using pyridine molecules as a linker to non-covalently attach NQDs to SWNTs, we were able to assemble NQDs on SWNTs with precise density control without harming their electronic structures. Furthermore, by measuring electrical signals from the fabricated aligned SWNTs-FET using dielectrophoresis (DEP), we were able to elucidate the charge transfer mechanism.

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A study on heavy metal migration in fly ash/bentonite using a reactive transport model

  • Jung, Yoo-Jin;Cho, Hee-Chan
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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    • pp.629-636
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    • 2003
  • The retardation of heavy metals in a mixture of fly ash and bentonite was studied as a potential barrier material for a landfill. Column tests were conducted using synthetic leachate having 100 mg/L and 50 mg/L of lead (Pb) and cadmium (Cd), respectively. Results indicated that the mixture had obvious retardation ability for heavy metals. To investigate the retardation factor caused by adsorption, batch adsorption tests were conducted at various concentrations. Test results were correlated with both Langmuir and Freundlich isotherms. The adsorption of the lead ion was applicable to the Langmuir isotherm and the adsorption of the cadmium ion was applicable to the Freundlich isotherm. In addition, based on experimental results, the migration characteristics of heavy metals through the bed of fly ash and bentonite mixture were investigated using the PHREEQC, a reactive transport model, under the real conditions of the landfill liner.

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VOCs 처리를 위한 미생물의 토양복원화 특성 (The Characteristics of Bioremediation for VOCs in Soil Column)

  • 손종렬;장명배;조광명
    • 환경위생공학
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    • 제17권1호
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    • pp.52-56
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    • 2002
  • The study was carried out to evaluate the characteristics of biodegradation by Pseudomonas putida G7 in soil column. The reactor system was used to investigate mass transfer of VOCs as Toluene in a column of unsaturated soil. Determination of the fate of VOCs in unsaturated soil is necessary to evaluate the feasibility of natural attenuation as a VOCs remediation strategy. The objective of this study was to develop a mechanistically based mathematical model that would consider the interdependence of VOC transport, microbial activity, and sorptive interactions in a moist, unsaturated soil. Because the focus of the model was on description of natural attenuation, the advective VOCs transport that is induced in engineered remediation processes such as vapor extraction was not considered. It can be concluded that the coefficient for gas liquid mass-transfer was found to be a key parameter controlling the ability of bacteria to VOCs. Finally, it appeared that bioremediation technology of VOCs which are difficult to be decomposed by chemical methods.

아크회전과 열팽창 방식을 적용한 소호부에 대한 아크유동 해석 (The development of computational fluid dynamics tools for thermal expansion type interrupter with the arc rotary)

  • ;이방욱;서정민
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 B
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    • pp.813-815
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    • 2000
  • This paper is concerned with the development of PC based computer simulation and design tools for auto-expansion SF6 circuit breaker with the arc rotary. The simulation model takes into account radiation transport, turbulence enhanced momentum. energy transport. The conversation gas dynamic equation together with Maxwells equations are solved. For the arc simulation the straightforward procedure has been used. The temperature, gas density and velocity space distributions within the circuit breaker are simulated in details. The presented results show that the computer simulation of gas flow in SF6 interrupter is a subject of much interest for design and optimization of contacts. The presented results show that the shape and sizes of contacts are chosen by this tool from judiciously compromise between electrical breakdown strength and interruption ability that are functions of gas flow parameters.

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구급대원의 재난대응역량에 관한 연구 (Study on disaster response competencies of 119 EMTs)

  • 이정혁;이경열
    • 한국응급구조학회지
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    • 제22권3호
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    • pp.55-66
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    • 2018
  • Purpose: This study was conducted to investigate the disaster response competencies of 119 emergency medical technicians (EMTs). Methods: The subjects of this study were 226 119 EMT's at the fire station located in G province. The questionnaire consisted of 5 sub-factors and 29 items for measuring disaster response competencies and the collected data were analyzed using SPSS program. Results: Disaster response competency comprising immediate response, patient triage, patient treatment, patient transport, and collaboration support were 3.48, 3.64, 3.52, 3.64, and 3.16, respectively. Advanced EMTs scored significantly higher in patient triage (p<.001), treatment (p<.001), and transport (p=.022) competency than basic EMTs. Conclusion: In order to improve disaster response competency, it is necessary not only to enhance individual ability but also to continue disaster management training with related organizations.

보안 서비스를 제공하기 위한 이동 에이전트 시스템의 설계에 관한 연구 (A Study for Mobile Agent System to Support Security Service)

  • 김현배
    • 정보교육학회논문지
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    • 제2권1호
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    • pp.130-137
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    • 1998
  • An agent is a computer program that acts autonomously on a computer system. A mobile agent is not bound to the system where it begins execution. It has an ability to transport itself from on e system in a network to another. Mobile agent system solve the network traffic problem. Moreover, the agent may utilize the object services of the destination agent system. In this study the mobile agent system is introduced to support security service.

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옥수수(Zea mays L.) 자엽초 절편에서 에틸렌 생성에 대한 오옥신의 작용 특성 (Specificity of Auxin Action on Ethylene Production in Corn Coleoptile Segments)

  • 윤인선
    • Journal of Plant Biology
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    • 제34권4호
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    • pp.325-330
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    • 1991
  • The ability of several auxin analogs to induce ethylene production was tested in the corn coleoptile. The synthetic auxins 1-naphthaleneacetic acid (1-NAA) and 2, 4-dichlorophenoxyacetic acid (2, 4-D) had strong stimulatory effects on ethylene induction surpassing that of IAA. Both 2-naphthalaneacetic acid (2-NAA) and 2, 6-dichlorophenoxy acetic acid (2, 6-D), structural analogs of these auxins, respectively, were found to be inactive. Treatment with NPA, a strong inhibitor of polar auxin transport, led to drastic increase in IAA-induced ethylene production while it has bo effect on ethylene production induced by 1-NAA. A positive correlative existed between intracellular auxin level and ethylene production.

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철도인입선 정비기본계획 추진방향 연구 (Development of the Master plan for Industrial railway tracks)

  • 김현웅;문대섭
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.902-906
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    • 2005
  • The ability of freight users to identify and to utilize options to move is limited. Saving in time and in fare to freight users could be significant if whole transport sequences could be planned and implemented with high level of service. In oder to improve the attractiveness of rail freight, it is essential that the industrial railway tracks between railway network and large scale logistics facilities are completely equipped. This article present the direction of the master plan of Korean industrial railway tracks.

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Anomalous Permeation Observed in Fluoropolymer

  • Lee, Sang-Wha
    • 한국막학회:학술대회논문집
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    • 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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    • pp.140-143
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    • 2004
  • Compatibility of polymeric materials governs their suitability for nearly all potential applications. An aspect of compatibility that is frequently important for fluoropolymers is their ability to isolate fluids by serving as a barrier to mass transport. This property is commonly expressed as permeability. In ideal cases, both solubility and diffusivity are constant at any given temperature and so the permeability is also a constant.(omitted)

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Chitosan and Its Derivatives for Gene Delivery

  • Lee, Knen-Yong
    • Macromolecular Research
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    • 제15권3호
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    • pp.195-201
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    • 2007
  • Non-viral vectors, including lipid- or polymer-based systems, have attracted much attention to date as a gene delivery vehicle, due to safety issues with viral vectors. Chitosan, a naturally existing cationic polymer, has shown great potential as a gene delivery carrier, as it has low immunogenicity and toxicity, excellent transcellular transport ability, and is relatively easy to chemically modify. This review summarizes and discusses the general features of chitosan and its applications as a delivery carrier of DNA and RNA.