• 전자공학회논문지A
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• 제29A권4호
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• pp.22-27
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• 1992

The cyclic voltammogram characteristics at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ ceramics/(($10^{-3}$M KCI + p-Si powders) and /(($10^{-4}$M CsNO$_3$ + n-GaAs powders) suspension interfaces have been studied using the microelectrophoresis and the cyclic voltammetric method. The negatively charged ions are specifically absorbed on the virgin and the magnetized SrO${\cdot}6Fe_{2}O_{3}$ ceramics surfaces. The zeta potentials of the p-Si and n-GaAs colloidal semiconductors are + 41mV and -44.8mV, respectively. The magnetization effects act as potential barriers at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ interfaces. The positivelely charged p-Si and the negatively charged n-GaAs colloidal semiconductors act as potential barriers at the virgin SrO${\cdot}6Fe_{2}O_{3}$ interfaces. On the other hand, the charged p-Si and n-GaAs colloidal semiconductors act as potential barrier scavengers at the magnetized SrO${\cdot}6Fe_{2}O_{3}$ interfaces. The magnetization effects and the charged colloidal semiconductor effects are irreversible and interdependent.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.743-746
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• 2003

We have successfully used hydrophobic direct-wafer bonding, along with H-induced layer splitting of Ge, to transfer 700nm think, single-crystal Ge films to Si substrates. Optical and electrical properties have been also observed on these samples. Triple-junction solar cell structures gown on these Ge/Si heterostructure templates show comparable photoluminescence intensity and minority carrier lifetime to a control structure grown on bulk Ge. When heavily doped p$^{+}$Ge/p$^{+}$Si wafer bonded heterostructures were bonded, ohmic interfacial properties with less than 0.3Ω$\textrm{cm}^2$ specific resistance were observed indicating low loss thermal emission and tunneling processes over and through the potential barrier. Current-voltage (I-V) characteristics in p$^{+}$Ge/pSi structures show rectifying properties for room temperature bonded structures. After annealing at 40$0^{\circ}C$, the potential barrier was reduced and the barrier height no longer blocks current flow under bias. From these observations, interfacial atomic bonding structures of hydrophobically wafer bonded Ge/Si heterostructures are suggested.ested.

• Metals and materials international
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• 제24권6호
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• pp.1232-1240
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• 2018

Corrosion properties of dissimilar friction stir welded 6061 aluminum and HT590 steel were investigated to understand effects of galvanic corrosion. As cathode when coupled, HT590 was cathodically protected. However, the passivation of AA6061 made the aluminum alloy cathode temporarily, which leaded to corrosion of HT590. From the EIS analysis showing Warburg diffusion plot in Nyquist plots, it can be inferred that the stable passivation layer was formed on AA6061. However, the weld as well as HT590 did not show Warburg diffusion plot in Nyquist plots, suggesting that there was no barrier for corrosion or even if it exists, the barrier had no function for preventing and/or retarding charge transport through the passivation layer. The open circuit potential measurements showed that the potential of the weld was similar to that of HT590, which lied in the pitting region for AA6061, making the aluminum alloy part of the weld keep corrosion state. That resulted in the cracked oxide film on AA6061 of the weld, which could not play a role of corrosion barrier.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1262-1264
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• 1995

The question-"How fast a electron tunnels a potential barrier?" looks like simple, but is controversy for more than 40 years. Because "tunneling" involves complicated internal processes and its definition is ambiguous. Recent experiments showed that the phase time is the best model of tunneling time among other times-for example, dwell time, Larmor clock time etc. In this paper, we simulated the tunneling time for Gaussian wave packet by program InterQuanta and compared with the phase time. In particular we focused on the effect of wave packet spreading in momentum space(or real space) which is not expressed by the phase time formula.

• 한국세라믹학회지
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• 제39권1호
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• pp.16-20
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• 2002

Semiconducting (Ba.Sr)TiO$_3$ceramic device, which shows the PTCR effect, has been usually used as a current limiter. In this case, the device should endure the condition under the high electric field. In this study, the dynamic electrical properties of the PTCR device under high voltage has been evaluated. Two different formulated powders were used and the sintered bodies exhibited the different grain size and porosity. The wide range of characterization such as complex impedance spectroscopy, microstructure, I-V characteristics and voltage dependence of resistivity of the samples were performed. The PTCR effect of the specimen containing coarse grains was very sensitively dependent on the AC electric field, showing that it was inversely pro-portional to the grain boundary potential barrier. The withstanding voltage was proportional to the potential barrier of grain boundary.

• 한국세라믹학회지
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• 제38권7호
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• pp.639-642
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• 2001

전형적인 비저항-온도 특성을 갖는 BaTiO$_3$계 PTC 세라믹을 일반적인 세라믹 공정을 이용하여 제조하였고, 결정립계면에 형성된 전위장벽의 높이를 구하였다. ZnO 바리스터의 전위장벽을 구하기 위해 이용되었던 커패시턴스-전압 관계식과는 다른 새로운 관계식을 제안하였고, 기존의 비저항-온도 관계식을 다소 변경한 관계식을 이용하여 전위장벽을 구하였다. 두 관계식으로부터 구한 전위장벽의 높이는 매우 유사한 값을 보이고 있으며 타 연구자들에 의해 보고된 값과도 잘 일치하고 있다. 비저항-온도 관계식과 커패시턴스-전압 관계식을 이용하여 130-18$0^{\circ}C$ 구간에서 구한 전위장벽의 크기는 각각 0.41-0.76V와 0.36-0.80V이었다.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.262-266
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• 2000

We investigated the effect of the grain size on the photovoltaic current in (Pb$_{1-x}$La$_x$)TiO$_3$ceramics, and the photoinduced domain switching in (Pb$_{0.85}$La$_{0.15}$)TiO$_3$and BaTiO$_3$ceramics. These behaviors in ferroelectric ceramics were attributed to the grain boundary at which photoexcited electrons were trapped. As the charged grain boundary acted as an electro-potential barrier which impeded the movement of electrons, the photovoltaic current showed a peak at a critical grain size. The space charge field built by the electrons trapped at the grain bound-aries was accounted for the photoinduced domain switching, and AE experimental results support well this account.

• 전자공학회논문지A
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• 제32A권7호
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• pp.58-68
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• 1995

Polysilicon capacitors with pyrogenic oxide and TEOX oxide as insulators were fabricated to develop capacitors which can be applied to analog CMOS IC, and the characteristics of the capacitors were compared with each other. The morphology of bottom polysilicon in pyrogenic oxide capacitor is degraded due to the generaged protuberances of the polysilicon grain during oxidataion. The polysilican capacitor with pyrogenic oxide of 57 nm thickness showed that the effective potential barrier height of 0.45 eV is much less than that of MOS capacitor (3.2 eV)when the top electrode is biased with a positive volgate. The morphology of the polysilicon capacitor with TEOS oxide, however, was not degraded during oxide deposition by LPCVD. The polysilicon capacitor with TEOS oxide of 54 nm thickness showed the effective potential barrier height of 1.28 eV when the top electrode is biased with a negative voltage. Therefore, it is concluded that the polysilicon capacitor with TEOS oxide is more applicable to analog CMOS IC than the pyrogenic oxide polysilicon capacitor.

• Bulletin of the Korean Chemical Society
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• 제13권4호
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• pp.385-388
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• 1992

The transition probabilities for the thermal intramolecular electron transfer and the optical intervalence transfer band for a symmetric mixed-valence Cu(I)-Cu(II) compound were used to extract the PKS parameters $\varepsilon$ = -1.15, ${\lambda}$ = 2.839, and ${\nu}g$- = 923 $cm^{-1}$. These parameters determine the potential energy surfaces and vibronic energy levels. Three pairs of vibrational levels are below the top of the energy barrier in the lower potential surface. The contribution of each vibrational state to the intramolecular electron transfer was calculated. It is shown that the three pairs of vibrational states below the top of the barrier are responsible for most of the electron transfer at 261-306 K. So the intramolecular electron transfer in this system is a tunneling process. The transition probability exhibits the usual high-temperature Arrhenius behavior, but at lower temperature falls off to a temperature-independent value as tunneling from the lowest levels becomes the limiting process.

• Asian-Australasian Journal of Animal Sciences
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• 제27권4호
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• pp.580-586
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• 2014

Intestinal epithelial cells (IECs) forming the barrier for the first-line of protection are interconnected by tight junction (TJ) proteins. TJ alteration results in impaired barrier function, which causes potentially excessive inflammation leading to intestinal disorders. It has been suggested that toll-like receptor (TLR) 2 ligands and some bacteria enhance epithelial barrier function in humans and mice. However, no such study has yet to be claimed in swine. The aim of the present study was to examine whether Bacillus subtilis could improve barrier integrity and protection against deoxynivalenol (DON)-induced barrier disruption in porcine intestinal epithelial cell line (IPEC-J2). We found that B. subtilis decreased permeability of TJ and improved the expression of zonula occludens (ZO)-1 and occludin during the process of forming TJ. In addition, ZO-1 expression of IPEC-J2 cells treated with B. subtilis was up-regulated against DON-induced damage. In conclusion, B. subtilis may have potential to enhance epithelial barrier function and to prevent the cells from DON-induced barrier dysfunction.