• Title/Summary/Keyword: $H_2$ doping concentration

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Comparison of Dye Removal Performance of Direct and Indirect Oxidation Electrode (직접 산화와 간접 산화용 전극의 Dye 제거 성능 비교)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Korean Society on Water Environment
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    • v.26 no.6
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    • pp.963-968
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    • 2010
  • This study has carried out to evaluate the performance of direct and indirect oxidation electrode for the purpose of decolorization of Rhodamine B (RhB) in water. Four kinds of electrodes were used for comparison: Pt and JP202 (indirect oxidation electrode), Pb and boron doping diamond (BDD, direct oxidation electrode). The effect of applied current (0.5 ~ 2.5 A), electrolyte type (NaCl, KCl, HCl, $Na_2SO_4$ and $H_2SO_4$) and electrolyte concentration (0.5 ~ 2.5 g/L), solution pH (3 ~ 11) and initial RhB concentration (25 ~ 125 mg/L) were evaluated. Experimental results showed that RhB removal efficiency were increased with increase of current, NaCl dosage and decrease of the pH. However, the effect of operating parameter on the RhB removal were different with the electrode type. JP202 electrode was the best electrode from the point of view of performance and energy consumption. The order of removed RhB concentration per energy lie in: JP202>Pt>Pb>BDD.

The study of diode characteristics on the doping concentration of ZnO films using the Si Substrate (Si 기판위에 형성된 ZnO 박막의 도핑 농도에 따른 다이오드 특성 연구)

  • Lee, J.H.;Jang, B.L.;Lee, J.H.;Kim, J.J.;Kim, H.S.;Jang, N.W.;Cho, H.K.;Kong, B.H.;Lee, H.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.216-217
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    • 2008
  • Zinc-oxide films were deposited by pulsed laser deposition (PLD) technique using doped ZnO target (mixed $In_2O_3$ 0.1, 0.3, 0.6 at. % - atomic percentage) on the p-type Si(111) substrate. A little Indium has added at the n-ZnO films for the electron concentration control and enhanced the electrical properties. Also, post thermal annealed ZnO films are shown an enhanced structural and controled electron concentration by the annealing condition for the hetero junction diode of a better emitting characteristics. The electrical and the diode characteristics of the ZnO films were investigated by using Hall effect measurement and current-voltage measurement.

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The effects of Germanium concentration and Hydrogen loading time on the growth of fiber Bragg grating (Ge 도핑농도와 수소처리시간 변화가 광섬유격자 형성에 미치는 영향)

  • Song, J.H.;Lee, J.H.;Song, J.T.;Lee, K.S.;Lee, Y.S.;Jeon, C.O.;Jeon, K.I.
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.993-995
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    • 1998
  • We fabricated fiber gratings with three different Ge-doped fibers exposed to 60atm pressure of Hz gas at 90"C for different times and studied the effects of Ge-doping concentration and $H_2$ loading time on the growth of gratings. According to experiments. the growing effect of hydrogen loading on high Ge-doped fiber was great.

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Study on the Emission Properties of Visible Light Source using Energy Transfer (에너지전달을 이용한 가시광 Light Source의 발광특성에 관한 연구)

  • Gu, Hal-Bon;Kim, Ju-Seung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.486-489
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    • 2003
  • Red organic electroluminescent(EL) devices based on poly(N-vinylcarbazole)(PVK) and tris(8-hydroxyquinorine aluminum)($Alq_3$) doped with red emissive material, 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran(DCJTB), poly(3-hexylthiophene)(P3HT), Rubrene and 4-dicyanomethylene-2-methyl-6[2-(2,3,6,7-tetrahydro-1H,5H-benzo-[i.j])quinolizin-8yl)vinyl-4H-pyran(DCM2) were fabricated. We examine the energy transfer from $Alq_3$ to DCJTB, P3HT, Rubrene and DCM2 by comparing between the PL and EL spectrum. The maximum peak PL intensities were achieved when the doping concentration of DCJTB, DCM2, P3HT and Rubrene has 5, 1, 0.5, 2wt%, respectively. The maximum luminance of device using DCJTB showed $594\;cd/m^2$ at 15V.

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Threshold Voltage Modeling of Double-Gate MOSFETs by Considering Barrier Lowering

  • Choi, Byung-Kil;Park, Ki-Heung;Han, Kyoung-Rok;Kim, Young-Min;Lee, Jong-Ho
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.7 no.2
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    • pp.76-81
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    • 2007
  • Threshold voltage ($V_{th}$) modeling of doublegate (DG) MOSFETs was performed, for the first time, by considering barrier lowering in the short channel devices. As the gate length of DG MOSFETs scales down, the overlapped charge-sharing length ($x_h$) in the channel which is related to the barrier lowering becomes very important. A fitting parameter ${\delta}_w$ was introduced semi-empirically with the fin body width and body doping concentration for higher accuracy. The $V_{th}$ model predicted well the $V_{th}$ behavior with fin body thickness, body doping concentration, and gate length. Our compact model makes an accurate $V_{th}$ prediction of DG devices with the gate length up to 20-nm.

Magnetic and Photo-catalytic Properties of Nanocrystalline Fe Doped $TiO_2$ Powder Synthesized by Mechanical Alloying

  • Uhm, Y.R.;Woo, S.H.;Lee, M.K.;Rhee, C.K.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.955-956
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    • 2006
  • Fe-doped $TiO_2$ nanopowders were prepared by mechanical alloying (MA) varying Fe contents up to 8.0 wt.%. The UV-vis absorption showed that the UV absorption for the Fe-doped powder shifted to a longer wavelength (red shift). The absorption threshold depends on the concentration of nano-size Fe dopant. As the Fe concentration increased up to 4 wt.%, the UV-vis absorption and the magnetization were increased. The benefical effect of Fe doping for photocatalysis and ferromagnetism had the critical dopant concentration of 4 wt.%. Based on the UV absorption and magnetization, the dopant level is localized to the valence band of $TiO_2$.

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Luminescence properties of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ red phosphor as the effect of Zn ion (Zn ion의 영향에 따른 $(Y,\;Zn)_2O_3$:$Eu^{3+}$ 적색 형광체의 발광특성)

  • Song, Y.H.;Moon, J.W.;Park, W.J.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.6
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    • pp.253-257
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    • 2008
  • To enhance the luminescence properties, the red phosphor composed of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ as doping concentration of Zn ion is synthesized at $1200^{\circ}C$ for 6 hrs in air atmosphere by conventional solid reaction method. As a result of the red phosphor $(Y,\;Zn)_2O_3$:$Eu^{3+}$ is measured X-ray diffraction (XRD), The main peak is nearly corresponded to the same as JCPDS card (No. 41-1105). When the doping concentration of Zn ion is more than 5 mol%, However, the ZnO peak is showed by XRD analysis. Therefore, when the doping concentration of Zn ion is less than 5 mol%, the Zn ion is well mixed in $Y_2O_3$ structure without the impurity phases. The photoluminescence (PL) properties is shown as this phosphor is excited in 254 nm region and the highest emission spectra of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ has shown in 612 nm region because of a typical energy transition ($^5D_0{\rightarrow}^7F_2$) of $Eu^{3+}$ ion. As the doping concentration of Zn ion is more than 10 mol%, the emission peak is suddenly decreased. when the highest emission peak as doping concentration of Zn ion is shown, the composition of this phosphor is $(Y_{0.95},\;Zn_{0.05})_2O_3$:$Eu^{3+}_{0.075}$ and the particle size analyzed by FE-SEM is confirmed from 0.4 to $3{\mu}m$.

Development of SiGe Heterostructure Epitaxial Growth and Device Fabrication Technology using Reduced Pressure Chemical Vapor Deposition (저압화학증착을 이용한 실리콘-게르마늄 이종접합구조의 에피성장과 소자제작 기술 개발)

  • Shim, K.H;Kim, S.H;Song, Y.J;Lee, N.E;Lim, J.W;Kang, J.Y
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.4
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    • pp.285-296
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    • 2005
  • Reduced pressure chemical vapor deposition technology has been used to study SiGe heterostructure epitaxy and device issues, including SiGe relaxed buffers, proper control of Ge component and crystalline defects, two dimensional delta doping, and their influence on electrical properties of devices. From experiments, 2D profiles of B and P presented FWHM of 5 nm and 20 nm, respectively, and doses in 5×10/sup 11/ ∼ 3×10/sup 14/ ㎝/sup -2/ range. The results could be employed to fabricate SiGe/Si heterostructure field effect transistors with both Schottky contact and MOS structure for gate electrodes. I-V characteristics of 2D P-doped HFETs revealed normal behavior except the detrimental effect of crystalline defects created at SiGe/Si interfaces due to stress relaxation. On the contrary, sharp B-doping technology resulted in significant improvement in DC performance by 20-30 % in transconductance and short channel effect of SiGe HMOS. High peak concentration and mobility in 2D-doped SiGe heterostructures accompanied by remarkable improvements of electrical property illustrate feasible use for nano-sale FETs and integrated circuits for radio frequency wireless communication in particular.

이종접합 태양전지용 p a-Si:H 에미터 층 최적화 및 태양전지 특성 거동 연구

  • Kim, Kyung Min;Jeong, Dae Young;Song, Jun Yong;Park, Joo Hyung;Oh, Byung Sung;Song, Jinsoo;Lee, Jeong Chul
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.129.2-129.2
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    • 2011
  • 본 연구에서는 a-Si:H/c-si 구조의 이종접합 태양전지의 p a-Si:H 에미터 층의 박막 조건에 따라 태양전지 특성을 연구하였다. p, n-layer는 PECVD (Plasma-enhanced chemical vapor deposition) i-layer는 HWCVD(Hot wire chemical vapor deposition), ITO는 RF 마그네트론 스퍼터링법으로 제작하였다. p-layer의 도핑 농도, 기판 증착 온도, 증착 높낮이에 따라 특성을 비교 분석 하였다. QSSPC로 minority carrier life time, 자외 가시선 분광분석 장치로 투과 반사도를, Ellipsometer로 흡수 계수, 두께, FTIR로 막의 구성요소 등의 변화를 조사하여 개선된 p a-Si:H의 특성이 이종접합 태양전지에서 효율향상에 영향을 주는지 Photo IV와 EQE를 통하여 조사하였다.

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Characteristics of IEF Patterns and SDS-PAGE Results of Korean EPO Biosimilars

  • Kang, Min-Jung;Shin, Sang-Mi;Yoo, Hey-Hyun;Kwon, Oh-Seung;Jin, Chang-Bae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.9
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    • pp.2493-2496
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    • 2010
  • Erythropoietin (EPO) is mainly produced in kidney and stimulates erythropoiesis. The use of recombinant EPOs for doping is prohibited because of its performance enhancing effect. This study investigated whether biosimilar EPOs could be differentiated from endogenous one by iso-electro-focusing plus double blotting and SDS-PAGE for antidoping analysis. The established method was validated with positive control urine. The band patterns were reproducible and meet the criteria, which was made by world anti doping agency (WADA). Isoelectric focusing was conducted in pH range 2 to 6. Recormon (La Roche), Aropotin (Kunwha), Epokine (CJ Pharm Co.), Eporon (Dong-A), Espogen (LG Life Sciences), and Dynepo (Shire Pharmaceuticals) were detected in basic region. All biosimilars showed discriminative isoelectric profiles from endogenous EPO profiles, but they showed different band patterns with the reference one except Epokine (CJ Pharm Co.). Next, SDS-PAGE of biosimilar EPOs resulted in different molecular weight patterns which were distributed higher than endogenous EPO. Commercial immune assay kit as an immune affinity purification tool and immobilized antibody coated magnetic bead were tested for the purification and concentration of EPO from urinary matrix. The antibody-coated magnetic bead gave better purification yield. The IEF plus double blotting and SDS-PAGE with immunoaffinity purification method established can be used to discriminate biosimilar EPOs from endogenous EPO.