• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.18-20
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• 2016

Transparent and conducting IGZO thin films were deposited by RF magnetron sputtering on thin Cu coated glass substrates to investigate the effect of a Cu buffer layer on the structural, optical, and electrical film properties. Although X-ray diffraction (XRD) analysis revealed that both the IGZO single layer and IGZO/Cu bi-layered films were in the amorphous phase, the IGZO/Cu films showed a lower resistivity of 5.7×10⁻⁴ Ωcm due to the increased mobility and high carrier concentration. The decreased optical transmittance of the IGZO/Cu films was also attributed to a one order of magnitude higher carrier concentration than the IGZO films. From the observed results, the thin Cu layer is postulated to be an effective buffer film that can enhance the opto-electrical performance of the IGZO films in transparent thin film transistors.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1553-1560
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• 2019

In a previous study, the antimicrobial peptides extracted from Lactobacillus plantarum UTNGt2 of wild-type fruits of Theobroma grandiflorum (Amazon) were characterized. This study aimed to investigate the antimicrobial mechanisms of peptides in vitro and its protective effect on fresh tomatoes. The addition of partially purified Gt2 peptides to the E. coli suspension cells at the exponential ($OD_{605}=0.7$) growth phase resulted in a decrease with 1.67 (log10) order of magnitude compared to the control without peptide. A marginal event (< 1 log10 difference) was recorded against Salmonella, while no effect was observed when combined with EDTA, suggesting that the presence of a chelating agent interfered with the antimicrobial activity. The Gt2 peptides disrupted the membrane of E. coli, causing the release of ${\beta}$-galactosidase and leakage of DNA/RNA molecules followed by cell death, revealing a bacteriolytic mode of action. The tomatoes fruits coated with Gt2 peptides showed growth inhibition of the artificially inoculated Salmonella cocktail, demonstrating their preservative potential.

• Structural Engineering and Mechanics
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• v.83 no.3
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• pp.401-413
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• 2022

The collapse of civil infrastructure due to natural disasters results in financial losses and many casualties. In particular, the recent increase in earthquake activities has highlighted on the importance of assessing the seismic performance and predicting the seismic risk of a structure. However, the nonlinear behavior of a structure and the uncertainty in ground motion complicate the accurate seismic response prediction of a structure. Artificial intelligence can overcome these limitations to reasonably predict the nonlinear behavior of structures. In this study, a deep learning-based algorithm was developed to estimate the time-history seismic response of bridge structures. The proposed deep neural network was trained using structural and ground motion parameters. The performance of the seismic response prediction algorithm showed the similar phase and magnitude to those of the time-history analysis in a single-degree-of-freedom system that exhibits nonlinear behavior as a main structural element. Then, the proposed algorithm was expanded to predict the seismic response and fragility prediction of a bridge system. The proposed deep neural network reasonably predicted the nonlinear seismic behavior of piers and bearings for approximately 93% and 87% of the test dataset, respectively. The results of the study also demonstrated that the proposed algorithm can be utilized to assess the seismic fragility of bridge components and system.

• Corrosion Science and Technology
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• v.17 no.3
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• pp.91-100
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• 2018

Development of biodegradable implants for treatment of complex bone fractures has recently become one of the priority areas in biomedical materials research. Multifunctional corrosion resistant and bioactive coatings containing hydroxyapatite $Ca_{10}(PO_4)_6(OH)_2$ and magnesium oxide MgO were obtained on Mg-Mn-Ce magnesium alloy by plasma electrolytic oxidation. The phase and elemental composition, morphology, and anticorrosion properties of the coatings were investigated by scanning electron microscopy, energy dispersive spectroscopy, potentiodynamic polarization, and electrochemical impedance spectroscopy. The PEO-layers were post-treated using superdispersed polytetrafluoroethylene powder. The duplex treatment considerably reduced the corrosion rate (>4 orders of magnitude) of the magnesium alloy. The use of composite coatings in inducing bioactivity and controlling the corrosion degradation of resorbable Mg implants are considered promising. We also applied the plasma electrolytic oxidation method for the formation of the composite bioinert coatings on the titanium nickelide surface in order to improve its electrochemical properties and to change the morphological structure. It was shown that formed coatings significantly reduced the quantity of nickel ions released into the organism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.320-320
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• 2010

In the case of existing ultrasonic motors, they have characteristics such as outstanding response speed, speed and high efficiency. However, it's very hard to use practically them as small motors due to complicated structure and expensive cost. This paper proposed v-type ultrasonic linear motor. Stator of the motor is composed of thin elastic body and four ceramics attached to upper and bottom areas of the body. The ceramics have each direction of polarization. When two harmonic voltages which had $90^{\circ}$ phase difference were applied to the ceramics, the symmetric and anti-symmetric displacements were generated at the tip to make the elliptical motion. To find out a model that generates maximum displacement at contact tip, FEM program was used with change of leg-angle. In addition, optimal model was chosen by considering magnitude and shape of displacement according to change of frequency.

• Journal of the Korea Safety Management & Science
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• v.4 no.4
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• pp.109-118
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• 2002

Such effects would be paid off in the right way only when management of the firms perform marketing activities focusing on long term effectiveness, which would drive company profits up and keep them for long. Demands of customers are being changed and varied. In this result with the advantage of mass marketing and database marketing have been drawing attentions from company. To fulfill these demands of customer, they need a concept of eCRM(Web based Customer Relationship Management), and go from selling products and services, or gathering customer requests, up to the phase of solving customer's problem by real time or previous action. With the help of internet, the frequency and speed of the problem solving has improved greatly. For these purposes, we try to determine the most important and most urgent factors in eCRM: utilization by using SN Ratio Decision making, one of the Multi-criteria decision-making methods SN Ratio Decision making is widely used for determining relative magnitude per evaluation item, i. e. priority on problems and is expected to make more systematic and objective evaluations than conventional methods do. Even in the present situation where any general criterion on eCRM dose not exist, utilization of eCRM is expected to be actively continued, which will cause many problems. In this regard, evaluating eCRM counts.

• Proceedings of the ESK Conference
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• 1993.04a
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• pp.1-9
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• 1993

A human gait study is required for the biomechanical design of running shoes. A tow-dimensional dynamic model was developed in order to analyze lower extremity kinematics and loadings at the right ankle, knee, and hip joints. The dynamic model consists of three segments, the upper leg, the lower leg, and the foot. Each segment was assumed to be a rigid body with one or two frictionless hinge joints. The lower extremity motion was assumed to be planar in the sagittal plane. A young male subject was involved in the gait test and his anthropometric data were measured for the calculation of segement mass and moment of inertia. The experimental data were obtained from three trials of walking at 1.2m/s. The foot-floor reaction data were measured from a Kistler force plate. The kinematic data were acquired using a three-dimensional motion measurement system (Expert Vision) with six markers, five of which were placed on the right lower extremity segments and the rest one was attached to the force plate. Based on the model and experimental data for the stance phase of the right foot, the calculated vertical forces reached up to 492, 540, and 561 N at the hip, knee, ankle joints, respectively. The flexion-extension moments reached up to 155, 119, and 33 Nm in magnitude at the corresponding joints.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.5
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• pp.14-20
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• 1997

This paper proposes a new design method for the SMC-type FLC and shows that a SMC-type LFC is an extension of the SMC with BL. The conventional SMC-type FLC uses error and change-of-error as inputs of the FLC and generates the absolute value of a switching magnitude. Then, the fuzzy rule table is constructed on a two-dimensional space of the phase plane and has commonly the skew symmetric property. In this paper, we introduce a new variable, signed distance, from the skew symmetric property of the rule table. And thd variable becomes only a fuzzy variable that is used to generate the control input of a SMC-type FLC. that is, we design a new SMC-type FLC that uses a signed distance and a control input as the variables representing the contents of the rule-antecedent and the rule-con-sequent, respectively. Then the number of total rules is reduced and the control performance is almost the same as that of the conventional SMC-type FLC. Additionally, we derive the control law of the ordinary SMC with BL from a new SMC-type FLC. Namely, we show that a FLC is an extension of the SMC with BL.

• Journal of Power Electronics
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• v.18 no.1
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• pp.251-265
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• 2018

To enable a master-slave control independent microgrid system (MSCIMGS) to supply electricity continuously, the microgrid inverter should perform mode transfer between grid-connected and islanding operations. Transient oscillations should be reduced during transfer to effectively conduct a seamless mode transfer. This study uses a typical MSCIMGS as an example and improves the mode transfer strategy in three aspects: (1) adopts a status-tracking algorithm to improve the switching strategy of the outer loop, (2) uses the voltage magnitude and phase pre-synchronization algorithm to reduce transient shock at the time of grid connection, and (3) applies the hybrid-sensitivity $H_{\infty}$ robust controller instead of the current inner loop to improve the robustness of the controller. Simulations and experiments show that the proposed strategy is more practical than the traditional proportional-derivative control mode transfer and effective in reducing voltage and current oscillations during the transfer period.

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.515-519
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• 1993

The retention behavior of proteins was investigated by using hydrophobic interaction chromatography (HIC), comparing to the results obtained in reversed-phase chromatography (RPC) described in the previous paper. A SynChropak propyl column was employed with 0.05 M phosphate buffer (pH 7.0) containing sodium sulfate. Conformational changes were recognized by examining Z values as a function of sodium sulfate concentration over a range of temperature between 5 and 65$^{\circ}C$. Z values did not change significantly at the range of the temperature showing the consistent ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ values. The sign and the magnitude of ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ of proteins in HIC were compared with those obtained in RPC. The signs of ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ of proteins in HIC were all positive, while those of proteins in RPC were all negative. These results suggested that the retention of proteins in HIC and in RPC were entropy-driven and enthalpy-driven process, respectively. From the two different investigations, it was concluded that the retention mechanism of RPC and HIC was based on the same fundamental principle in which separation is dependent on hydrophobicity, but the retention behavior of the proteins in HIC is clearly different from that observed in RPC.