• Title/Summary/Keyword: Substrate loss

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Corrosion Characteristics of Cast Stainless Steel under Plasma Ion Nitriding Process Temperature in Marine Environment (주조 스테인리스강의 해양환경 하에서 플라즈마 이온질화 공정온도에 따른 부식특성 연구)

  • Chong, Sang-Ok;Kim, Seong-Jong
    • Journal of the Korean institute of surface engineering
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    • v.50 no.6
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    • pp.504-509
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    • 2017
  • In order to improve corrosion resistance for cast stainless steel in seawater, the characteristics of corrosion resistance after plasma ion nitriding was investigated. Plasma ion nitriding process was conducted in a mixture of nitrogen of 25% and hydrogen of 75% at substrate temperature ranging from 350 to $500^{\circ}C$ for 10 hours using pulsed-DC glow discharge plasma with working pressure of 250 Pa in vacuum condition. Corrosion tests were carried out for as-received and plasma ion nitrided specimens. The corrosion characteristics were investigated by measurement of weight loss and observation of surface morphology. In anodic polarization experiment, relatively less damage depth and weight loss were presented at a nitrided temperature of $400^{\circ}C$, attributing to the formation of S-phase.

A Study on Wear Resistance of TiN Films Prepared by Arc Vapor Ion Deposition Process (Arc Vapor Ion Deposition 법으로 제조된 TiN 피막의 내마모성에 관한 연구)

  • 신현식;한전건;장현구;고광진
    • Journal of the Korean institute of surface engineering
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    • v.27 no.1
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    • pp.36-44
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    • 1994
  • The TiN films were deposited on the stainless substrates using arc vapor ion deposition process to in-vestigated the wear resistance. Pin-on-disc tests were performed to measure the volume wear loss of TiN films. The substrate bias voltages and nitrogen flow rates were selected as the deposition parameters of TiN films. It was found that the wear resistance of TiN films was enhanced with increasing bias voltages(0~-300 V) and nitrogen flow rates(220~380 SCCM). The volume wear loss TiN films were about 9.5~2.1$\times$$10^{-3}mm^3$ and 3.5~2.2$\times$$10^{-3}mm^3$ with bias voltages and nitrogen flow rates, respectively.

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FR-4 Embedded UWB Filter using Uniform Impedance Resonator (임피던스 공진기를 이용한 FR-4 임베디드 광대역필터)

  • Yang, Chang-S.;Yoon, Sang-K.;Park, Jae-Y.
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.8
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    • pp.1471-1475
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    • 2007
  • In this paper, a novel embedded ultra wideband (UWB) band-pass filter is presented on a FR-4 package substrate including high Dk resin coated copper (${\varepsilon}_r=30$) film. The proposed UWB filter is comprised of a parallel resonator with meander-type uniform impedance resonator (UIR) and two series resonators with high Q circular stacked spiral inductor and metal-insulator-metal (MIM) capacitor. In order to obtain excellent attenuation characteristics by generating attenuation poles in lower and upper stop bands, a single MIM capacitor is added to each resonator. The fabricated FR-4 embedded UWB filter has insertion loss of -1.0dB and return loss of -11dB, respectively. It has also extremely wide bandwidth (over 50%) and small size ($3.7{\times}4{\times}0.77\;mm^3$) which is compatible with LTCC devices.

The Structure and Dielectric Properties of BST Thin Films Using Fractal Process (프렉탈 처리를 이용한 BST 박막의 구조 및 유전적특성)

  • 기현철;박지순;이우기;민용기;김태성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.43-46
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    • 2000
  • In this study, (Ba, Sr)$TiO_3$ (BST) ceramics thin films were prepared by Sol-Gel method. BST solution was made and spin-coated on Pt/$TiO_2$/Si substrate at 4000 [rpm] for 10 seconds. Coated specimens were dried at 150[$^{\circ}C$] for 5 minutes. Coating process was repeated 3 times and then sintered at 750[$^{\circ}C$] for 30 minutes. Structure and electrical characteristics of specimen was analyzed by Fractal Process. Thickness of BST ceramics thin films are about 2800[$\AA$]. Dielectric constant and loss of thin films was little decreased at 1[kHz]~1[MHz]. Dielectric constant and loss to frequency were 250 and 0.02 in BST3. The property of leakage current as the relation between the current and the voltage was that change of the leakage current was stable when the applied voltage was 0~3[V].

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Photoelectrochemical Hydrogen Production on Textured Silicon Photocathode

  • Oh, Il-Whan
    • Journal of the Korean Electrochemical Society
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    • v.14 no.4
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    • pp.191-195
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    • 2011
  • Wet chemical etching methods were utilized to conduct Si surface texturing, which could enhance photoelectrochemical hydrogen generation rate. Two different etching methods tested, which were anisotropic metal-catalyzed electroless etching and isotropic etching. The Si nano-texture that was fabricated by the anisotropic etching showed ~25% increase in photocurrent for H2 generation. The photocurrent enhancement was attributed to the reduced reflection loss at the nano-textured Si surface, which provided a layer of intermediate density between water and the Si substrate.

Fabrication and characterization of integrated optic wavelength demultiplexer using a chirped grating (Chirped 회절격자를 이용한 집적형 파장분할 다중화기 제작 및 특성 측정)

  • 서만수
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.232-236
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    • 1990
  • Optical waveguide was fabricated in the soda lime glass substrate using rapid thermal method. A chirped grating having period variation of 0.41 - 0.51${\mu}{\textrm}{m}$ on this waveguide for WDM was made. And then, arranging input and output optical fiber, wavelength division multiplexer with 5 channels in short wavelength region was realized. Experiment result of this WDM showed that wavelength spacing, 3 dB bandwidth, insertion loss and crosstalk were 5nm, 4nm, 40dB and less than -10dB, respectively.

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New Hairpin Type Bandpass Filter (BPF) (새로운 헤어핀 타입 대역통과필터)

  • 채동규;김동현;임문혁;윤기완
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.05a
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    • pp.457-459
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    • 2003
  • A new hairpin type bandpass fille. (BPF) with novel type of resonators on Teflon substrate is designed, measured, and compared with its simulation results. The proposed filter seems to have advantages of low cost and low loss, thus being very useful for 12 GHz RF applications.

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Design ofa wideband HTS antenna

  • Hwang, Jong-Sun;Park, Sung-Jin;Han, Byoung-Sung;Chung, Dong-Chul
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.197-200
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    • 2000
  • In this paper, we present a novel methodology for a wideband HTS antenna of finite length placed on a dielectric substrate. A methodology used in this work is based on a moment-method techniques with Green function singularity when the field point is in the source triangle. The designed resonance frequency of our HTS antenna is 11.85 GHz. The return loss is -26 dB. The bandwidth obtained is a significant 10.6 %. Experimental measurements for a HTS antenna designed in X-band are shown to agree well with the simulated prediction.

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Miniaturized Silicon Micromachined Bandpass Filter

  • 육종관
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.5
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    • pp.680-687
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    • 1999
  • An extensive study on miniaturized bandpass filter(BPF) appropriate for mobile communication systems is presented in this paper. The miniaturization has been accomplished by incorporating low-loss high-index materials inside a resonating cavity fabricated in silicon substrate using micromachining etching techniques. By use of materials with dielectric constant $\varepsilon_r$=500, filters with volume less than 0.11 $mm^3$ have been designed at the center frequency of 5.8 GHz with 3.3% bandwidth. The electrical performances and design tolerances of these filters for a variety of materials and shapes are discussed and design guidelines are presented herein.

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Effects of Habitat and Nutrient Content of Leaves on the Litter Decomposition of Larix kaempferi and Quercus serrata at Kwangnung (광릉의 잎갈나무(Larix kaempferi)와 졸참나무(Quercus serrata) 낙엽의 분해에 미치는 잎의 영양함량과 입지의 영향)

  • 박봉규
    • Journal of Plant Biology
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    • v.23 no.2
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    • pp.45-48
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    • 1980
  • Effects of habitat and substrate quality on decomposition rate of litters of Larix kaempferi and Quercus serrata were estimated in Kwangnung forest. The amount of organic matter under the canopy of Quercus serrata stand was higher than that under the canopy of Larix kaempferi. The loss constant of litters in the Larix kaempferi stand was higher than that in the Quercus serrata stand.

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