• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.766-772
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• 1996

Undoped $SnO_x$ thin films were deposited on Si(100) substrate by using reactive ioassisted deposition technique (R-IAD). In order to investigate the effect of initial oxygen content and heat treatment on the oxidation state and crystalline structure of tin oxide films, $SnO_x$ thin films were post-annealed at 400~$600^{\circ}C$ for 1 hr. in a vacuum ~$5 \times 10^{-3}$ -3/ Torr or were directly deposited on the substrate of $400^{\circ}C$ and the relative arrival ration ($Gamma$) of oxygen ion to Sn metal varied from 0.025 to 0.1, i.e., average impinging energy ($E_a$) form 25 to 100 eV/atom. As $E_a$ increased, the composition ratio of $N_ON{sn}$ changed from 1.25 to 1.93 in post-annealing, treatment and 1.21 to 1.87 in in-situ substrate heating. In case of post-annealing, the oxidation from SnO to $SnO_2$ was closely related to initial oxygen contents and post-annealing temperature, and the perfect oxidation of $SnO_2$ in the film was obtained at higher than $E_a$=75 eV/atom and $600^{\circ}C$. The temperature for perfect oxidation of $SnO_2$ was reduced as low as $400^{\circ}C$ through in-situ substrate heating. The variation of the chemical state of $SnO_x$ thin films with changing $E_a$'s and heating method were also observed by Auger electron spectroscopy.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.832-834
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• 1999

This paper is a study on the real-position measurements of mobile object using n network. 2-D PSD sensor is used to measure th position of moving object with light source. Position Sensitive Detector(PSD) is an useful which can be used to measure the position o incidence light in accuracy and in real-time. T the position of light source of moving target, neural network technique are proposed and applied. Real-time position measurements of the mobile robot with light source is examined to validate the proposed method. It is shown that the proposed technique provides accurate position estimation of the moving object.

• Journal of the Korean institute of surface engineering
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• v.40 no.4
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• pp.170-174
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• 2007

High Velocity Oxygen Fuel (HVOF) thermal spray coating of nano size WC-Co powder (nWC-Co) has been studied as one of the most promising candidate for the possible replacement of the traditional hard plating in some area which causes environmental and health problems. nWC-Co powder was coated on Inconel 718 substrates by HVOF technique. The optimal coating process obtained from the best surface properties such as hardness and porosity is the process of oxygen flow rate (FR) 38 FMR, hydrogen FR 57 FMR and feed rate 35 g/min at spray distance 6 inch for both surface temperature $25^{\circ}C\;and\;500^{\circ}C$. In coating process a small portion of hard WC decomposes to less hard $W_2C$, W and C at the temperature higher than its decomposition temperature $1,250^{\circ}C$ resulting in hardness decrease and porosity increase. Friction coefficient increases with increasing coating surface temperature from 0.55-0.64 at $25^{\circ}C$ to 0.65-0.76 at $500^{\circ}C$ due to the increase of adhesion between coating and counter sliding surface. Hardness of nWC-Co is higher or comparable to those of other hard coatings, such as $Al_2O_3,\;Cr,\;Cr_2O_3$ and HVOF Tribaloy 400 (T400). This shows that nWC-Co is recommendable for durability improvement coating on machine components such as high speed spindle.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1104-1108
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• 2007

Conducting Polypyrrole-lead titanate (PPy/PbTiO3) composites have been prepared by in situ deposition technique by placing different wt.% of fine grade powder of PbTiO3 (10, 20, 30, 40, and 50%) during polymerization of pyrrole. The composites formed were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), and these data indicate that PbTiO3 particles are dominating with an increase in crystallinity as well as thermal stability of the composites. The results on the low frequency dielectric studies which are obtained in the form of pressed pellet state are interpreted in terms of Maxwell Wagner polarization, which are responsible for the dielectric relaxation mechanism and frequency dependence of conductivity.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.433-436
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• 1990

An optimal Stabilization technique for a bilinear in duction model is introduced. This technique includes to o parts; the one is an stabilization control using Lyap unov Function which has the form of a sum of linear and quadratic function of the state variables, and the other is an optimal control using the performance index which depends on the choice of the elements of the Ly apunov matrices concerning both the state variables and the input variables. Therefore, induction motor is drived with the shorter transient time of the state variables and with the smaller overshoot of the ones, simulation results are obtained from a digital computer. Experimental ones are obtained from implementation of the optimizing controller using 8086 microprocessor kits and analog circuits are compared.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.3
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• pp.291-300
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• 2016

The emergence of smart devices and IoT leads to the appearance of O2O service to blur the difference between online and offline. As online services' merits were added to the offline market, it caused a change in the dynamics of the offline industry, which means the offline-space's digitization. Unlike these changing aspects of the offline market, exhibition industry grows steadily in the industry, however it is also possible to create a new value added by combining O2O service. We conducted a survey targeting 20 spectators in '2015 Seoul Design Festival' at COEX. The survey was used to analysis of the spatial structure and generate the dataset for machine learning. We identified problems with the analysis study of the existing spatial structure, and based on this investigation we propose a new method for analyzing a spatial structure. Also by processing a machine learning technique based on the generated dataset, we propose a novel evaluation model of exhibition-space cells for O2O service layout.

• Applied Microscopy
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• v.36 no.spc1
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• pp.63-69
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• 2006

By utilizing a field emission gun and a biprism installed on a transmission electron microscope (TEM), electron holography is extensively carried out to visualize the electric and magnetic fields of nanomaterials. In the electric field analysis, the distribution of electric potential in a sharp tip made of W coated with $ZrO_2$ is visualized by applying the voltage to the tip. Denser contour lines due to the electric potential are observed with an increase in the bias voltage. In the magnetic field analysis by producing the strong magnetic field with a sharp magnetic needle made of a permanent magnet, the in situ experiment is carried out to investigate the magnetization of hard magnetic materials. The results of these experiments clearly demonstrate that electron holography is a promising advanced transmission electron microscopy technique to characterize the electric and magnetic properties of nanomaterials.

• Journal of Microbiology
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• v.35 no.4
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• pp.300-308
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• 1997

The catechol 2,3-dioxygenase (C23O) encoded by the Pseudomonas putida xylE gene was over-produced in Escherichia coli and purified to homogeneity. The activity of the C23O required the reduced form of the Fe(II) ion since the enzyme was highly susceptible to inactivation with hydrogen perocide but reactivated with the addition of ferrous sulfate in conjunction with ascorbic acid. The C23O activity was abolished by treatment with the chemical reagents, diethyl-pyrocarbonate (DEPC), tetranitromethane (TNM), and 1-cyclohexy1-3-(2-morpholinoethyl) car-bodiimidemetho-ρ-toluenesulfontate (CMC), which are modifying reagents of histidine, tyrosine and glutamic acid, respectively. These results suggest that histidine, tyrosine and glutamic acid residues may be good active sites for the enzyme activity. These amino acid residues are conserved residues may be good active sites for the enzyme activity. These amino acid residues are conserved residues among several extradion dioxygenases and have the chemical potential to serveas ligands for Fe(II) coordination. Analysis of random point mutants in the C23O gene derived by PCR technique revealed that the mutated positions of two mutants, T179S and S211R, were located near the conserved His165 amd Hos217 residues, respectively. This finding indicates that these two positions, along with the conserved histidine residues, are specially effective regions for the enzyme function.

• Water for future
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• v.10 no.2
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• pp.113-124
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• 1977

Alone the southwesten coast of Korean peninsula, the extensive available arable acreages suited for forming are found in the development of tidal flats in the geographically curved bays with a motable tidal emplitude. It was found that the developments of these tidal flats cover an estimated area more than 276,000ha. In this paper, a flood control system by Pul's Storage Indication Method and Pul's Graphical Method at Return Periods-50 yrs, design rainfall-267mm per 48hrs and design flood-926c.m.s. and at 0.2meter control height above the High Water Ordinary Spring Tide Level (+11.0m) was studied. At the result, the flood demage in the reservoir at Return Periods-50 yrs and the tidal level at H.W.O.S.T.L. were satisfied to the below E.L. 11.20m (Flood Level in the reservoir). Well skilled flood control technique and management and control of draining sluice gate should be required for the disaster prevention from the flood and tide damage.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.254-259
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• 2007

In this report, several fabrication techniques for the formation of various nanochannels (with $SiO_2$, Si, or Quartz) are introduced. Moreover, simple fabrication technique for generating $SiO_2$ nanochannels without nanolithography is presented. By using different nanochannels, the degree of stretching DNA molecule will be evaluated. Finally, we introduce a nanometer scale fluidic channel with electrodes on the sidewall of it, to detect and analyze single DNA molecule. The cross sectional shape of the nanotrench is V-groove, which was implemented by thermal oxidation. Electrodes were deposited through both sidewalls of nanotrench and the sealing of channel was done by covering thin poly-dimethiysiloxane (PDMS) polymer sheet.