• Title/Summary/Keyword: nanomembrane

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Thermo-Field emission in silicon nanomembrane ion detector for mass spectrometry (실리콘 나노 박막의 열-전계 방출효과를 이용한 분자 질량분석)

  • Park, Jong-Hoo
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.4
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    • pp.586-591
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    • 2013
  • This paper describes the characteristics of thermo-field emission in a freestanding silicon nanomembrane under ion bombardment with various thermal and field conditions. The thermal effect and field effect in thermo-field emission in silicon nanomembrane are investigated by varying kinetic energy of ions and electric field applied to the silicon nanomembrane surface, respectively. We found that thermo-field emission increases linearly as the electric field increases, when the electric field intensity is lower than the threshold. The thermo-field emission (schottky effect) increases proportionally to the power of temperature, which agree well with the predictions of a thermo-field emission model.

Field Emission from Free-standing Nanomembrane For High Energy Ion Detection (Free-standing 박막의 전계 방출 특성을 이용한 고에너지 이온 디텍터에 관한 연구)

  • Park, Jong-Hoo
    • Journal of the Korean Magnetics Society
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    • v.21 no.5
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    • pp.163-166
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    • 2011
  • We describe modified Fowler-Nordheim (FN) field emission equation for the free-standing nanomembrane cathode, which has mechanical degrees of freedom. The derived FN equation agrees well with the experimental data. The free-standing nanomambrane cathode demonstrates its unique ability to detect large biomolecure ions.

A comparative study for guided bone regeneration of silk fibroin nanomembrane(NanoGide-$S^{TM}$) (실크 피브로인 나노 차폐막(나노가이드-에스)을 이용한 치조골 유도재생능력에 관한 비교 연구)

  • Han, Dae-Hyun;Hong, Ki-Seok;Chung, Chin-Hyung;Yim, Sung-Bin
    • Journal of Periodontal and Implant Science
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    • v.38 no.3
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    • pp.475-482
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    • 2008
  • Purpose: To evaluate the safety and efficiency of bone regenerative abilities of silk fibroin nanomembrane(Nanoguide-S) Material and Methods: The objects were 38 patients who had large defect at extraction sockets caused by chronic periodontitis and silk fibroin nano matrix were used on experimental group(N=19) and PLA/PLGA matrix were used on control group(N=19). The width, height, and length by crown-apical direction(socket depth) of defects were measured with the occlusal plane as a reference plane, and tooth axis direction, perpendicular to tooth axis direction were measured on radiographs at 3 months pre-operative, 3 months post-operative. Result: Tissue response to silk fibroin nano matrix and Biomesh were clinically satisfactory and complications such as swelling, exudation, ulceration and vesicles were not found except the ordinary discomfort of operated portion. 3 months later, the width, height, and length by crown-apical direction (socket depth) of defects were clinically improved in both groups with no significant difference. 3 months later radiolucency of tooth axis direction and perpendicular to tooth axis direction were all increased in both groups with no significant difference. Conclusion: By these results biodegradadable silk fibroin nano matrix was efficient in GBR on alveolar bone resorption caused by periodontitis compared to Biomesh.

Numerical Analysis on Thermal Transpiration Flows for a Micro Pump (열천이 현상을 이용한 마이크로 펌프내의 희박기체유동 해석)

  • Heo, Joong-Sik;Lee, Jong-Chul;Hwang, Young-Kyu;Kim, Youn-J.
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.493-496
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    • 2006
  • Rarefied gas flows through two-dimensional micro channels are studied numerically for the performance optimization of a nanomembrane-based Knudsen compressor. The effects of the wall temperature distributions on the thermal transpiration flow patterns are examined. The flow has a pumping effect, and the mass flow rates through the channel are calculated. The results show that a steady one-way flow is induced for a wide range of the Knudsen number. The DSMC(direct simulation Monte Carlo) method with VHS(variable hard sphere) model and NTC(no time counter) techniques has been applied in this work to obtain numerical solutions.

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Numerical Analysis on Thermal Transpiration Flows for a Micro Pump (열천이 현상을 이용한 마이크로 펌프내의 희박기체유동 해석)

  • Heo, Joong-Sik;Lee, Jong-Chul;Hwang, Young-Kyu;Kim, Youn-J.
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.5
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    • pp.27-33
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    • 2007
  • Rarefied gas flows through two-dimensional micro channels are studied numerically for the performance optimization of a nanomembrane-based Knudsen compressor. The effects of the wall temperature distributions on the thermal transpiration flow patterns are examined. The flow has a pumping effect, and the mass flow rates through the channel are calculated. The results show that a steady one-way flow is induced for a wide range of the Knudsen number. The DSMC(direct simulation Monte Carlo) method with VHS(variable hard sphere) model and NTC(no time counter) techniques has been applied in this work to obtain numerical solutions. A critical element that drives Knudsen compressor Is the thermal transpiration membrane. The membranes are based on aerosol or machined aerogel. The aerogel is modeled as a single micro flow channel.

Transferrable single-crystal silicon nanomembranes and their application to flexible microwave systems

  • Seo, Jung-Hun;Yuan, Hao-Chih;Sun, Lei;Zhou, Weidong;Ma, Zhenqiang
    • Journal of Information Display
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    • v.12 no.2
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    • pp.109-113
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    • 2011
  • This paper summarizes the recent fabrication and characterizations of flexible high-speed radio frequency (RF) transistors, PIN-diode single-pole single-throw switches, as well as flexible inductors and capacitors, based on single-crystalline Si nanomembranes transferred on polyethylene terephthalate substrates. Flexible thin-film transistors (TFTs) on plastic substrates have reached RF operation speed with a record cut-off/maximum oscillation frequency ($f_T/f_{max}$) values of 3.8/12 GHz. PIN diode switches exhibit excellent ON/OFF behaviors at high RF frequencies. Flexible inductors and capacitors compatible with high-speed TFT fabrication show resonance frequencies ($f_{res}$) up to 9.1 and 13.5 GHz, respectively. Robust mechanical characteristics were also demonstrated with these high-frequency passives components.