• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.9-15
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• 2007

A comparative study of the structure and organization of the primary and secondary walls in different types of tropical plant waste fibers was carried out using transmission electron microscopy (TEM). The thickness of each layer was also measured using Image Analyzer. TEM micrographs haveconfirmed that cell wall structure of all six types of tropical plant waste fibers (empty fruit bunch, oil palm frond, oil palm trunk, coir, banana stem and pineapple leaf) has the same ultrastructure with wood fibre. The fibers consisted of middle lamella, primary and thick secondary wall with different thickness for different types of fibers. The secondary wall was differentiated into a $S_1$ layer, a unique multi-lamellae $S_2$ layer, and $S_3$ layer.

• Transactions on Electrical and Electronic Materials
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• v.3 no.4
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• pp.27-31
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• 2002

Thin film diode with reliable interfacial structure was fabricated by using multi-step anodic oxidation. The thickness of the oxide layer was preciously controlled with anodic voltage. Also, interfacial structure between oxide layer and top electrode was improved by applying post heat-treatment. The thin film diode showed symmetric and stable I-V characteristics after the post heat-treatment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.296-302
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• 2009

In this paper, a planar microstrip patch antenna is proposed using the slit on the top layer of a multi-layered structure for GPS application. The proposed antenna has a circular polarization at 1,575.42 MHz. This proposed antenna is fabricated on multi-layered FR4 substrate. The slits embedded on the top plane may yield to lower a resonance frequency and sustain a broad bandwidth. The proposed antenna size is $20{\times}20{\times}4.0\;mm^3$. The measured gain of 0.5 dBi, 10 dB bandwidth(VSWR 2:1) of 70 MHz(4.4 %), and 3 dB axial-ratio bandwidth of 15 MHz(1 %) have been obtained, respectively.

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.317-328
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• 2013

In this paper, the optimization has been performed to design a multi-layer structure that is used as a structure for noise reduction of acoustic sonar sensors in underwater vehicles. Two design goals are considered to reduce self-noise from own machineries and to enhance acoustic signals detected from outside. Both distinct and continuous design parameters have been used such as selection of material properties of each layer and thickness of each layer, respectively. The sensitivity of design parameters has been analyzed and the evolutionary algorithm has been implemented for design optimization. For design optimization process, each of the design goals and the two combined design goals have been considered to analyze the achievement of those design goals.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.9-12
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• 2016

The process parameters of DC pulsed sputtering to produce a multi-layer thin film with light reflectance at a specific wavelength region were studied. The optical simulation of multi-layer thin films of the silicon dioxide ($SiO_2$) films with a low refractive index and the titanium dioxide ($TiO_2$) films with a high refractive index was done. Under a DC pulsed sputtering power of 2kW and 200 sccm(standard cubic centimeter per minute) argon gas, the silicon dioxide films with a refractive index of 1.46 in the range of oxygen gas ratios of 12% and a titanium dioxide film with a refractive index of 2.27 in the range of oxygen gas ratios of 1% were produced. The multi-layer structure of high refractive index/low refractive index/high refractive index was designed and fabricated. The characteristics of the fabricated multi-layer thin film structure showed a reflectance of more than 45% in the range, 780 to 1200nm. This multi-layer structure is expected to be used to block the near infrared wavelength light.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.341-344
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• 2000

Several new via structures in printed circuit boards are proposed, fabricated and characterized in RF regime. The new structure with a larger inductance component in the bottom layer shows 3㏈ improvement over the conventional structure. The ADS simulation with model parameters extracted from 3D fie]d solver matches with the characterization of these vias

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.653-656
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• 2002

In this paper, we present the simulation results of multi-layer VCO(voltage controlled oscillator), which is composed of resonator, oscillator, and buffer circuit, using EM simulator and nonlinear RF circuit simulator. EM simulator is used for obtaining the EM(Electromagnetic) characteristics of conductor pattern as well as designing the multi-layer VCO. Obtained EM characteristics were used as real components in nonlinear RF circuit simulation. Finally the overall VCO was simulated by the nonlinear RF circuit simulator. The material for the circuit pattern was Ag and the dielectric was DuPont 951AT, which will be applied for LTCC process. The structure of multi-layer VCO is constructed with 4 conducting layer. Simulated results showed that the output level was about 4.5 [dBm], the phase noise was -104 [dBc/Hz] at 30 [kHz] offset frequency, the harmonics -8 dBc, and the control voltage sensitivity of 30 [MHz/V] with a DC current consumption of 9.5 [mA]. The size of VCO is $6{\times}9{\times}2$ mm(0.11[cc]).

• Journal of the Korean institute of surface engineering
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• v.39 no.1
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• pp.9-12
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• 2006

Al-doped ZnO(AZO)/Ag/AZO multi-layer films deposited on PET substrate by RF magnetron sputtering have a much better electrical properties than Al-doped ZnO single-layer films. The multi-layer structure consisted of three layers, AZO/Ag/AZO, the optimum thickness of Ag layers was determined to be $112{\AA}$ for high optical transmittance and good electrical conductivity. With about $1800{\AA}$ thick AZO films, the multi-layer showed a high optical transmittance in the visible range of the spectrum. The electrical and optical properties of AZO/Ag/AZO were changed mainly by thickness of Ag layers. A high quality transparent electrode, having a resistance as low as $6\;W/{\square}$ and a high optical transmittance of 87% at 550 nm, was obtained by controlling Ag deposition parameters.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.481-481
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• 2000

We investigated the structure-activity relationships on use of multi-layer neural networks. The relationships are techniques required in developments of medicines. Since many kinds of observations might be adopted on the techniques, we discussed some points between the observations and the properties of multi-layer neural networks. In the structure-activity relationships, an important property is not that standard deviations are nearly equal to zero for observed physiological activity, but prediction ability for unknown medicines. Since we adopted non-linear approximation, the function to represent the activity can be defined by observations; therefore, we believe that the standard deviations have not significance. The function was examined by "leave-one-out" method, which was originally introduced for the multi-regression analysis. In the linear approximation, the examination is significance, however, we believe that the method is inappropriate in case of nonlinear fitting as neural networks; therefore, we derived a new index fer the relationships from the differential of information propagation in the neural network. By using the index, we discussed physiological activity of an anti-cancer medicine, Mitomycine derivatives. The neuro-computing suggests that there is no direction to extend the anti-cancer activity of Mitomycine, which is close to the trend of anticancer developing.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.443-447
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• 2004

In this study, we investigated the necessity of encapsulation layer to maximize flexibility of brittle indium-tin-oxide (ITO) on polymer substrates. And, Young's modulus (E) of encapsulation layer han a significant effect on external bending stress and the coefficient of thermal expansion (CTE) of that han a significant effect on internal thermal stress. To compare the magnitude of total mechanical stress including both bending stress and thermal stress, the mechanical stress of triple-layer structure (substrate / ITO / encapsulation layer or substrate / buffer layer / ITO) can be quantified and numerically analyzed through the farthest cracked island position. As a result, it should be noted that multi-layer structures with more elastic encapsulation material have small mechanical stress compared to that of buffer and encapsulation structure of large Young's modulus material when they were externally bent.