• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.889-892
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• 2009

We have developed a practical printing technology for the gate electrode of organic thin film transistors(OTFTs) by combining screen-printing with wet-etching process using nano-silver ink as a conducting material. The screen-printed and wet-etched Ag electrode exhibited a minimum line width of ~5 um, the thickness of ~65 nm, and a resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, producing good geometrical and electrical characteristics for gate electrode. The OTFTs with the screen-printed and wet-etched Ag electrode produced the saturation mobility of $0.13cm^2$/Vs and current on/off ratio of $1.79{\times}10^6$, being comparable to those of OTFT with the thermally evaporated Al gate electrode.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.108-114
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• 2002

This paper describes the design of a robust adaptive controller for a nonlinear dynamical system with unknown nonlinearities. These unknown nonlinearities are approximated by multilayered neural networks (MNNs) whose parameters are adjusted on-line, according to some adaptive laws far controlling the output of the nonlinear system, to track a given trajectory. The main contribution of this paper is a method for considering input constraint with a rigorous stability proof. The Lyapunov synthesis approach is used to develop a state-feedback adaptive control algorithm based on the adaptive MNN model. An overall control system guarantees that the tracking error converges at about zero and that all signals involved are uniformly bounded even in the presence of input saturation. Theoretical results are illustrated through a simulation example.

• Journal of the Optical Society of Korea
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• v.8 no.1
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• pp.1-5
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• 2004

Using the external cavity spectroscopy method, we have observed the saturated absorption spectrum of the P(16) line of the v$_1$+v$_3$ band of $^{13}C$_2$H$_2$$. The frequency of a laser has been stabilized to the saturated absorption spectrum. The relative contrast of the saturation spectrum is about 7% with respect to the linear absorption and the linewidth is about 1.8 MHz. The frequency fluctuation of the stabilized LD is about $\pm$ 20 KHz for a sampling time of 100 ms.

• 전기의세계
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• v.27 no.5
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• pp.69-75
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• 1978

3 phase induction motor applied in the method of connecting it directly across the line needs large current when it starts. At that time, leakage magnetic pathes of interior of the motor are severely saturated and leakage reactances are decreased because of saturation. Consequently, increased current and raised powerfactor yield increase of starting torque. The author, noticing those phenomena, derived experimentally the raion of decreasing leakage reactance from the fact that when voltage applied to motor is increased under locked condition the magnitude of current and phase angle are varied, and determined tha equations of starting current and starting torque, considering the decrease of leakage reactance by the large starting current. The author calculated the characteristics of Current-Time and Speed-Time with the determined equation at specific load conditions, and compared the values obtained from above calculations with those from circle diagram's method and the practically recorded values at same load conditions. Therefore, the authos got a confidience that the results of the derived theory coincide with the practically measured values more well than circle diagram's results and circle diagram's equation should be modified in order to analize the starting status of a induction motor.

• 한국기계연구소 소보
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• s.20
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• pp.41-48
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• 1990

Electro-pneumatic valves are an electro-mechanical device which convert electric signal into pneumatic flow rate or pressure signal. Recently, the development tendency of electro-pneumatic valve is to make the valve with more compact and less electric power consumption style. To make the valve such as a style, the role of solenoid part is very important. This paper is used in the finite-element method for the purpose of evaluating the magnetic property of solenoid and analyze flux distribution of solenoid theoretically. From flux contour line which is obtained by numerical analysis, it verified that the plunger shape and physical property of solenoid part have influence on saturation phenomenon and leakage of magnetic fluxs. This paper made an experiment on the measurement of dynamic response time and force in order to confirm the propety of analytic result, and confirmed a good agreement between analysis results and experiment results.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.378-387
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• 2010

In this paper, we present new structure of wideband parabolic gain equalizer for TWT applied to printed circuit board. The gain equalizer is manufactured by using design variables of transmission line obtained from derived formulae. We compared the test results of two equalizers(reference equalizer and our equalizer). From that, we confirmed the validity of presented method. The presented equalizer is 1/3 times lighter, 1/2.7 times smaller and 1/10 times chipper than those of reference equalizer(Inmet company), respectively.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.21-24
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• 2002

The vector control system of an induction motor is the high performance drive system to achieve the instantaneous torque control. The vector control system is greatly divided into the direct control, and the indirect control that the most widely is used, The indirect vector control needs the rotor time constant, which changes widely according to the temperature, frequency, and current amplitude. The incorrect time constant leads to the saturation of magnetic flux or under-excitation phenomena. As a result, that deteriorate the control performance. Therefore, in this paper, the effect of time constant variation is investigated and its on-line tuning algorithm is proposed. The time constant using the torque angles was calculated and that of the validity of algorithm proposed was proved through the computer simulation and the experiment.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.117.2-117.2
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• 2003

The mechanism by which lead enters glial cells was examined. The uptake of lead reached saturation when assays were performed in buffers at pH 5.5 and 7.4. The Vmax and Km was 2.7 pmoles/mg protein/min and 13.4 M in the buffer at pH 7.4, respectively, whereas the Vmax and Km was 329 fmoles/mg and 8.2 M in the buffer at pH 5.5, respectively. Uptake in a buffer at pH 5.5 but not at pH 7.4 was inhibited by iron. Cells treated with the iron chelator desferoxamine displayed higher levels of the divalent metal transporter mRNA and protein. (omitted)

• Journal of ILASS-Korea
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• v.26 no.4
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• pp.171-181
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• 2021

This study presents a prediction methodology of thermodynamic properties by using RK-PR Equation of State in a wide range of temperature and pressure conditions including both sub-critical and super-critical regions, in order to obtain thermophysical properties for hydrocarbon aviation fuels and their products resulting from endothermic reactions. The density and the constant pressure specific heat are predicted in the temperature range from 300 to 1000 K and the pressure from 0.1 to 5.0 MPa, which includes all of the liquid and gas phases and the super-critical region of three representative hydrocarbon fuels, and then compared with those data obtained from the NIST database. Results show that the averaged relative deviations of both predicted density and constant pressure specific heat are below 5% in the specified temperature and pressure conditions, and the major sources of the errors are observed near the saturation line and the critical point of each fuel.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.6
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• pp.613-619
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• 1987

In a room air conditioning cooling system, if the room-sensible-heat-factor as plotted on a Psychrometric Chart intersects the saturation curve below the apparatus leaving air dewpoint, reheat must be used to maintain the design room air conditions. However, if the design room humidity is permitted to be raised to some degree, the cooling system will not require reheat as a new room-sensible-heat-factor line is developed between the apparatus leaving air dew-Point and the adjusted design room air conddition point. The advantages to this are the cost of reheat equipment and operation can be avoided. The cycle of this system can be shown on a Psychrometric Chart to plot the design condition points.