• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.15-20
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• 2000

In this paper. Thermally Stimulated Current spectra have been measured in the Polypy - romellitimide (polyimide). As a result of the investigation. three peaks have been observed: $A(50^{\circ}C)$, $B(120^{\circ}C)$, $C(200^{\circ}C)$. Among three peaks, C peak has been observed in detail. The C peak is shown to be created due to the polarization of ionic space charge from the experimental results which were measured as a function of forming time, forming temperature. forming voltage and collecting voltage. As a result, we have measured the TSC in ion ($Na^+$) implanted - Polyimide, also found the peak at $215^{\circ}C$. Therefore, TSC characteristics in the C peak is probably caused by residual impurity. And The activation energy caculated by means of initial rising method 1.8eV, hopping distance. $90{\AA}$. and the mobility. $2.88{\times}10^{-11}cm^2/v.s$

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.625-629
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• 2016

Electrical and optical properties of the AC voltage driven organic light-emitting diodes were investigated by measuring the electroluminescence of the device. Device structure of ITO(170 nm)/TPD(40 nm)/Alq3(60 nm)/LiF(0.5 nm)/Al(100 nm) was manufactured using a thermal evaporation. Sinusoidal and square-type AC voltage was applied to the device using a function generator. Amplitude of the applied voltage was 9.0 V, and a frequency was varied from 50 Hz to 50 kHz. Electroluminescence out of the device was measured in a Si photodetector simultaneously with the applied voltage together. An intensity and a delayed residual luminescence from the device were depended on the frequency of the sinusoidal voltage. It is thought to be due to a contribution of the capacitive nature in the equivalent circuit of the device. An electron mobility was estimated using a time constant obtained from the luminescence of the device driven by the square-type AC voltage.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2102-2103
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• 2008

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device(RCD) of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms](KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this paper is proposed to a electrical fire disaster prevention device(EFDPD) for a RCD trip or a self circuit-breaking function on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Steel and Composite Structures
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• v.25 no.5
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• pp.557-569
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• 2017

Moment-thrust-curvatures ($M-P-{\Phi}$ curves) are fundamental quantities for detailed descriptions of basic properties such as stiffness and strength of a section under axial loads required for accurate computation of the deformations of reinforced concrete or composite columns. Currently, the finite-element-based methods adopting small fibers for analyzing a section are commonly used for generating the $M-P-{\Phi}$ curves and they require large amounts of computational time and effort. Further, the conventional numerical procedure using the force-control method might encounter divergence problems under high compression or tension. Therefore, this paper proposes a divergence-free approach, combining the use of the displacement-control and the Quasi-Newton scheme in the incremental-iterative procedure, for generating the $M-P-{\Phi}$ curves of arbitrary sections. An efficient method for computing the strength from concrete components is employed, where the stress integration is executed by layer-based algorithms. For easy modeling of residual stress, cross sections of structural steel components are meshed into fibers for strength resultants. The numerical procedure is elaborated in detail with flowcharts. Finally, extensive validating examples from previously published research are given for verifying the accuracy of the proposed method.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.34-43
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• 2006

This paper shows modeling methods for VBR video trace. It is well known that VBR video trace is characterized as longterm correlated and highly intermittent burst data. To analyze this, we attempt to model it using neural network with auxiliary linear structures derived from residual threshold. For testing purpose, we generate VBR video trace from chaotic nonlinear function combined with the geometric random noise. The modeling result of the generated data shows that the attempted method represents more accurately than the traditional neural network. However, we also found that combining hRU to the attempted modeling method can yield a closer agreement to statistical features of the generated data than the attempted modeling method alone.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.15-20
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• 2010

In this paper, we discuss a decentralized observer design problem for the fault detection in the large-scale continuous-time T-S (Takagi-Sugeno) fuzzy system. Since the fault detection residual is desired to be as sensitive as possible, on the fault, we use $\mathfrak{H}_-$ index performance criterion. Sufficient conditions for the existence of such a observer is presented in terms of linear matrix inequalities. Simulation results show the effectiveness of the proposed method.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.19-24
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• 1992

Formula feed for fattening cattle ground through 2 mm screen was incubated in the rumen of sheep and goats to evaluate effects of ratio of concentrate to hay and kinds of hay in a ration on determining the degradability (dg) value of protein using in sacco technique. Following results were obtained: 1) Residual dry matter (DM) and crude protein (CP) of formula feed decreased as the time of incubation increased. Regression analyses showed that rates of degradation of DM and CP in the rumen were not the same when they were determined under feeding of rations with different percentages of concentrate. 2) Rate of passage of digesta from the rumen differed between feeding of Italian ryegrass hay ration and that of alfalfa hay ration, but was not influenced by the percentage of concentrate in a ration. 3) The dg value was different when it was estimated with results obtained from determinations under feeding of Italian ryegrass hay ration or that of alfalfa hay ration. The percentage of concentrate in a ration had no influence on the dg value of protein in formula feed.

• The International Journal of Costume Culture
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• v.7 no.1
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• pp.40-47
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• 2004

The purpose of this research was to examine the degradation rate of alizarin in accelerated degradation conditions using the GC-MS quantitative analysis. Alizarin dye solution (2.5 x 10/sup -3/ M conc.) were kept in 150℃ oven for total of 7 days and the degradation rate was examined each day. 2.5 × 10/sup -4/M conc. alizarin dye solution was mixed with H₂O₂ according to [H₂O₂]/[dye] ratio 40 and were kept under 365㎚ UV for 2 hours, analyzed after 0, 30, 60, 90, 120min using the GC-MS. Gas chromatogram showed alizarin peak at 9.96 - 10.13 min. retention time range and residual peaks in the wide range from 9.6 to 11.1 min. Oven degradation exhibited an initial decrease in the amount of alizarin, which was followed by increasing amount in 4/sup th/ day. The decrease in the alizarin was significantly shown by the 7/sup th/ day. Same pattern was also observed in the H₂O₂/UV/O₂ degradation samples and was verified ed by the UV-VIS spectra. The differences in the amount of alizarin between 1/sup st/ day and 4/sup th/ day samples, 4/sup th/ day and 7/sup th/ day samples, and Control and 7/sup th/ day samples of the oven degradation were significant at alpha .20.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.511-516
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• 2001

Recently small punch creep testing (or miniature disc bend creep test) has received much attention through European collaborative research projects. This method was considered as a substitute for the conventional creep rupture testing by which the residual creep life is measured from the specimen taken out from serviced components of high temperature plants. It would be beneficial if the material creep properties such as power law creep constants as well as the creep rupture life can be measured from the small punch creep test. In this paper a method of assessing creep constants from the small punch creep testing is proposed. Finite element analyses were performed to investigate evolution of stress and strain rate at the weakest locations of the small punch creep specimen. Elastic-plastic-secondary creep analyses were carried out. The estimation equations for creep constants by the small punch creep testing are proposed based on the finite analysis results. Small punch creep tests were also performed with 9Cr steel and the accuracy of the proposed equation was verified by the experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.537-543
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• 2003

Transient vibration generated by developing localized fault in gear can be used as indicators in gear fault detection. This vibration signal suffers from the background noise such as gear meshing frequency and its harmonics and broadband noise. Thus in order to extract the information about the only gear fault from the raw vibration signal measured on the gearbox this signal is processed to reduce the background noise with many kinds of signal-processing tools. However, these signal-processing tools are often very complex and time waste. Thus. in this paper. we propose a novel approach detecting the damage of gearbox and analyzing its pattern using the raw vibration signal. In order to do this, the residual signal. which consists of the sideband components of the gear meshing frequent) and its harmonics frequencies, is extracted from the raw signal by the power spectral density (PSD) to obtain the information about the fault and is used as the input data of the artificial neural network (ANN) for analysis of the pattern of gear fault. This novel approach has been very successfully applied to the damage analysis of a laboratory gearbox.