• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.199-205
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• 2011

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1 um) and gold film (1-2 um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed micro structure of grains of about 100 nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Journal of IKEEE
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• v.25 no.1
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• pp.37-41
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• 2021

In this paper, a low-profile and broadband bowtie antenna using multi-layer substrate for UWB sensor application is presented. A compact bowtie antenna is designed and implemented on two multi-layered substrate with total thickness of 4.5 mm. The antenna consists of bowtie radiator and planar-type balun. The designed radiator and balun are connected to each other so that it can be easily implemented in various structures. The implemented antenna provides 3 to 6 dBi of gain for whole frequency range from 6.8 to 10 GHz.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• Polymer(Korea)
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• v.39 no.3
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• pp.514-521
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• 2015

In this study, we would like to describe peel strength and dynamic shear property on various substrates of multi-layered structural double-sided adhesive tape with or without adhesive (AD) prepared by UV curing for an automobile, construction, and display junction. According to adapt the adhesive, the peel and dynamic shear strength of adhesion tape prepared with acrylic foam or various plastic substrates increased with increasing molecular weight, however, decreased over 650000 molecular weight. The adhesion property shows high value at the thin AD layer with decreasing temperature. The interface property shows highest at MW 615000 (AD-4), and the interface junction below MW 615000 resulted to divide from acrylic foam and adhesive layer. From this study, the multi-layered structural double-sided adhesive tapes seem to be a useful for industrial area such as a low surface energy plastic material and curved substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.322-323
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• 2008

Multi layered thin films with ZnS/$Na_3AlF_6$/ZnS were deposited on glass substrate by thermal evaporator precess and simulated by using EMP(Essential Macleod Program). EMP is a comprehensive software package to design and analyse the optical characteristics of multi-layered thin film. ZnS and $Na_3AlF_6$ were selected as a high refractive index and low refractive index material respectively. Additionally Cu was chosen as mid reflective material. Optical properties including color effect were systematically studied. in terms of different optical thickness of low refractive index material. The optical thickness of $Na_3AlF_6$ was changed as 0.25, 0.5, 0.75 and $1.0\lambda$. The film with 0.25, 0.5, 0.75 and $1.0\lambda$. of optical thickness showed mixed color range between bluish green and red purple, yellowish green and bluish green, purple and mixed color range of green and purple respectively.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1129-1132
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• 1995

In the preparation of the layered $BaTiO_3$ thin films with high performance, the new stacking method using the continuous cooling of the substrate was introduced. Amorphous/polycrystalline $BaTiO_3$ layered structure was confirmed by SEM and index of refraction. The layered $BaTiO_3$ thin films formed by the new stacking method showed such a high dielectric constant that the layered structure could not be explained by a stacking structure of the two defined layers but could only be explained by multi-layered structure, i.e. amorphous/micro crystalline/polycrystalline structure. The layered $BaTiO_3$ thin film with a thickness of 240 nm showed higher capacitance per unit area and breakdown strength than the double layered $BaTiO_3$ thin film prepared by the conventional stacking method. And well defined ferroelectric hysteresis leer was observed in the layered $BaTiO_3$ thin film with a thickness of 200 nm.

• Journal of Biomedical Engineering Research
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• v.29 no.1
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• pp.52-58
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• 2008

The object of this study is to investigate the effects of intermittent cyclic stretching on the smooth muscle cells (SMCs) seeded onto aligned multi-layered fibrous scaffold. To make multi-layered fibrous scaffold, polyurethane (PU) and poly(ethylene oxide) (PEO) were electrospun alternatively, then were immersed into distilled water to extract PEO. Various types of scaffolds were fabricated depending on fiber directions, i.e., aligned or randomly oriented. The direction of stretching was either parallel or vertical to the fiber direction for the aligned scaffolds. The stretching was also applied to the randomly aligned scaffolds. The duration of stretching was 2 min with 15 min resting period. During the stretching, the maximum and minimum strain was adjusted to be 10 and 7%, respectively with the frequency of 1 Hz. The bioactivities of cells on the scaffolds were assessed by quantifying DNA, collagen, and glycosaminoglycan (GAG) levels. And the cell morphology was observed by staining F-actin. SMCs under parallel stretching to the fiber direction responded more positively than those in other conditions. From the results, we could explain the morphological effect of a substrate on cellular activities. In addition the synergistic effects of substrate and mechanical stimuli effects were confirmed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.535-536
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• 2008

Multi-layered thin films of ZnS/$Na_3AlF_6$/ZnS/Cr were deposited on glass substrate by evaporation process. ZnS and $Na_3AlF_6$ were selected as high and low refractive index material, and additionally Cr was chosen as mid reflective layer respectively. The multi-layered thin films were prepared in terms of different optical thickness and different staking sequence and layers. The optical properties were systematically characterized with different optical thickness of $Na_3AlF_6$ especially $0.25\lambda$ and $0.5\lambda$. In order to expect the experimental result, the simulation program, the Essential Macleod Program(EMP) was adopted. Based on the results taken by spectrophotometer at viewing angle $45^{\circ}$, the ZnS/$Na_3AlF_6$/ZnS/Cr multi-layered thin film shows purple colour range in $0.25\lambda$， bluish green in $0.5\lambda$, red purple in $0.75\lambda$, and purple in $1.0\lambda$ respectively.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.582-588
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• 2012

In this paper, a highly miniaturized and performed UWB bandpass filter has been newly designed and implemented by embedding all the passive elements into a multi-layered PCB substrate with high dielectric $SrTiO_3$ composite film for 3.1 - 4.75 GHz compact UWB system applications. The high dielectric composite film was utilized to increase the capacitance densities and quality factors of capacitors embedded into the PCB. In order to reduce the size of the filter and avoid parasitic EM coupling between the embedded filter circuit elements, it was designed by using a $3^{rd}$ order Chebyshev circuit topology and a capacitive coupled transformation technology. Independent transmission zeros were also applied for improving the attenuation of the filter at the desired stopbands. The measured insertion and return losses in the passband were better than 1.68 and 12 dB, with a minimum value of 0.78 dB. The transmission zeros of the measured response were occurred at 2.2 and 5.15 GHz resulting in excellent suppressions of 31 and 20 dB at WLAN bands of 2.4 and 5.15 GHz, respectively. The size of the fabricated bandpass filter was $2.9{\times}2.8{\times}0.55(H)mm^3$.

• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.472-476
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• 2008

The surface region of commercial stainless steel 304 and 316 plates has been modified through deposition of the multi-layered coatings composed of titanium film ($0.1{\mu}m$) and gold film ($1-2{\mu}m$) by an electron beam evaporation method. XRD patterns of the stainless steel plates deposited with conductive metal films showed the peaks of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The stainless steel plates modified with $0.1{\mu}m$ titanium film and $1{\mu}m$ gold film showed microstructure of grains of under 100 nm diameter. The external surface of the stainless steel plates deposited with $0.1{\mu}m$ titanium film and $2{\mu}m$ gold film represented somewhat grain growth of Au grains in FE-SEM image. The electrical resistance and water contact angle of the stainless steel bipolar plates modified with multi-layered coatings were examined with the thickness of the gold film.