• Title/Summary/Keyword: Conductance

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Measurement of Real Outgassing Rate using Double Conductance Method (이중 콘덕턴스법에 의한 실기체방출률 측정)

  • 인상렬
    • Journal of the Korean Vacuum Society
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    • v.5 no.3
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    • pp.175-180
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    • 1996
  • Double conductance method is proposed as an effectvie way to measure real outgassing rates of materials regardless of their adsorbing power. The real outgassing rate and the sticking coefficient of the CFC (carbon fiber composite) which is used widely as the material for armor plates infusion experiment devices were obtained by adopting this method. At $40^{\circ}C$ the real ougassing rate was $Pa, m^3/s.m^2$(in $N_2$ equivalent), which was higher than 5 times the measured one, and the sticking coefficient was about 0.018($H_2O\; and \;H_2$ were the main residual gases).

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Conductance Difference of Single Molecular Junctions between Experiments and Computational Simulations

  • Choi, Ji Il;Kim, Hu Sung;Kim, Young-Hoon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.184.2-184.2
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    • 2014
  • Recent advances in the synthesis and characterization of nanoscale objects provided us with the atomistic understanding of charge transport through single molecular junctions. The representative examples are the mechanically controlled break junction technique and STM or conducting AFM junction techniques. Theoretical studies have been reported on the dependence of electronic charge transport on the geometry of molecule-electrode contacts, the critical element toward the realization of molecular electronics. In this report, we will clarify the puzzling discrepancies between theoretical predictions and experiments.

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Transient Stability Analysis of Power System by Transient Energy Method (과도에너지법에 의한 전력계통의 과도안정도 해석에 관한 연구)

  • 김준현;설용태
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.32 no.2
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    • pp.59-64
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    • 1983
  • This paper deals with the transient energy method of transient stability analysis of multi-machine power system by improving the transfer conductance, the kinetic energy and the critical transient energy. The tranfer conductance is considered more correctly, the generators of system are seperated to two states (critical and the rest state)and the correction term of critical transient energy (to reference point) is added. This analysis is performed by digital computer simulation and the application of this method to two model systems has shown its superiority to other available methods.

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Conformational and Conductance Fluctuations in Single-Molecule Junctions: A Multiscale Computational Study

  • Kim, Hu-Seong;Kim, Yong-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.389-389
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    • 2010
  • 우리 연구그룹에서는 분자 소자에서의 소자 구조와 전도도 간의 상관관계를 알아보기 위해서 분자동역학 전산모사와 전자밀도범함수이론 계산 및 전하수송성 계산을 자동으로 수행할 수 있는 소프트웨어를 개발하고 이를 적용해 다양한 나노소자를 연구하고 있다. 본 발표에서는 hexanedithiolate 단일 분자가 Au(111) 전극 사이에서 다양한 S-Au 접점 구조를 가지고 구성된 소자 모델에서 열적 진동이 소자 전도도에 끼치는 효과를 통계적으로 분석하여 단분자 소자 실험에서 제기된 여러 개의 conductance peak의 측정에 대한 논란에 대해 이론적인 규명을 시도할 것이다.

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Quenched Fano effect due to one Majorana zero mode coupled to the Fano interferometer

  • Wang, Qi;Zhu, Yu-Lian
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1275-1279
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    • 2018
  • We investigate the change of the Fano effect by considering one Majorana zero mode to couple laterally to the single-dot Fano interferometer. It is found that the Majorana zero mode quenches the Fano effect thoroughly and causes the conductance to be independent of the dot level, the dot-lead coupling, and the increase of the Majorana-dot coupling. As a result, the linear conductance becomes only related to the interlead coupling and the magnetic-flux phase factor. These results can be helpful for the detection of Majorana zero mode.

ATP Modulation of Cloned Rat Brain Large-conductance $Ca^{2+}$-activated $K^+$ Channel by Protein Phosphorylation

  • Park, S.Y.;S. Chung
    • Proceedings of the Korean Biophysical Society Conference
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    • 1999.06a
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    • pp.63-63
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    • 1999
  • Large conductance $Ca^{2+}$-activated $K^{+}$ channels (Maxi-K channel) have been implicated in many important physiological processes such as co-ordination of membrane excitability in neurons. Modulation of these channels are archived by the activity of various protein kinases. The most widely studied example of Maxi-K channel regulation by protein phosphorylation has been obtained using plasma membranes from the rat brain incorporated into lipid bilayers.(omitted)

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UV Effect on Plant Growth

  • Kondo, Noriaki;Tou, Seiji;Takahashi, Shinya;Nakajima, Nobuyoshi
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.158-161
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    • 2002
  • UV-B radiation gives harmful effects on plants, such as production of several types of DNA lesions, and growth inhibition. On the other hand, plants have some protective mechanisms, including filtering effect due to accumulation of phenolic compounds in epidermal cells and reactivation of DNA lesions, which are enhanced by UV-B irradiation. We have investigated the mechanism of UV-B effects on plants using cucumber seedlings as plant materials. Cucumber plants were cultivated in an artificially lit growth chamber. Supplemental UV-B irradiation, of which intensity was almost equal to the level of natural sunlight, retarded the growth of first leaves. The growth retardation must result trom the inhibition of cell division and/or cell growth. Microscopical observation of leaf epidermis suggested that the growth retardation might be mainly caused by cell growth inhibition. The retardation was, however, restored within 2 or 3 days after the termination of UV-B irradiation. It is known that UV-B irradiation lowers the activity of photo system II (PS II). In the present experimental conditions, however, UV-B irradiation has little effect on PS II activity as estimated by chlorophyll fluorescence. The stomatal conductance, a major factor determining photosynthetic rate, of first leaves increased during the growth. The increase of stomatal conductance was suppressed by UV-B irradiation and restored by termination of the irradiation. It has not been clear, however, what mechanisms are involved in the suppression of increase of stomatal conductance.

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Electrical Biosensor Of Kinase Assay on the MWCNT Nanoelectrode

  • Lee, Jae-Shin;Lee, Seok-Jae;Park, Jong-Pil;Park, Tae-Jung;Kim, Do-Hyun;Lee, Sang-Yup;Jung, Dae-Hwan;Jung, Hee-Tae;Kim, Jin-Hee;Kwon, Seong-Ku
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1193-1196
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    • 2004
  • We have demonstrated the use of MWCNT as a nanoscale probe to monitor the activity of enzyme kinase. To immobilize the substrate peptide using carbodiimide chemistry, plasma or strong acid treatments were used to induce carboxyl groups on the sidewall of MWCNTs. After the susbtrate peptide immobilization, increase of conductance from MWCNT devices was observed. When peptide modified MWCNTs react with enzyme kinase, conductance decreases by several orders of magnitude, and this conductance change can be explained by the phosphorylation reaction of enzyme kinase. When the sample was incubated with phosphatase to dephosphorylate the substrate peptide, nearly complete recovery of the conductance signal has been observed. 4 for 6 devices appeared the same trends. So, we can confirm that we have monitored the kinase activity on the MWCNT surface by electrical detection.

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Characteristics of Photosynthesis with Growing Stages by different Shading Materials in Panax Ginseng C. A. Meyer (차광재료에 따른 생육시기별 인삼의 광합성작용의 특성)

  • Lee, Chung-Yeol
    • Korean Journal of Medicinal Crop Science
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    • v.15 no.4
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    • pp.276-284
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    • 2007
  • To investigate the influence of shading materials with growing stages in Panax Ginseng C. A. Meyer, the diurnal change of photosynthesis, stomatal conductance, transpiration and its any correlation were measured. The net photosynthetic rate and stomatal conductance of ginseng were higher in the morning than in the broad day. The net photosynthetic rate was increased as the PAR (Photosynthetically Action Radiation) was increased and it was reached the maximum at the $200\;{\mu}mol/m^2/s$ of PAR in overall leaves. Transpiration rate was increased in the afternoon compared to in the morning. The transpiration rate was higher in rain shelter shading plate than in polyethylene net. A linear equation was obtained between net photosynthetic rate and stomatal conductance in the morning. SPAD was higher in rain shelter shading plate than in polyethylene net through all growth stages. It may result from the decrease of growth progress. From investigating photosynthetic characteristics, we concluded that shading plate of rain shelter was more an efficient material to ginseng growth.