• Title/Summary/Keyword: Free Si

Search Result 891, Processing Time 0.041 seconds

Analysis of Output Characteristics of Lead-free Ribbon based PV Module Using Conductive Paste (전도성 페이스트를 이용한 무연 리본계 PV 모듈의 출력 특성 분석)

  • Yoon, Hee-Sang;Song, Hyung-Jun;Go, Seok-Whan;Ju, Young-Chul;Chang, Hyo Sik;Kang, Gi-Hwan
    • Journal of the Korean Solar Energy Society
    • /
    • v.38 no.1
    • /
    • pp.45-55
    • /
    • 2018
  • Environmentally benign lead-free solder coated ribbon (e. g. SnCu, SnZn, SnBi${\cdots}$) has been intensively studied to interconnect cells without lead mixed ribbon (e. g. SnPb) in the crystalline silicon(c-Si) photovoltaic modules. However, high melting point (> $200^{\circ}C$) of non-lead based solder provokes increased thermo-mechanical stress during its soldering process, which causes early degradation of PV module with it. Hence, we proposed low-temperature conductive paste (CP) based tabbing method for lead-free ribbon. Modules, interconnected by the lead-free solder (SnCu) employing CP approach, exhibits similar output without increased resistivity losses at initial condition, in comparison with traditional high temperature soldering method. Moreover, 400 cycles (2,000 hour) of thermal cycle test reveals that the module integrated by CP approach withstands thermo-mechanical stress. Furthermore, this approach guarantees strong mechanical adhesion (peel strength of ~ 2 N) between cell and lead-free ribbons. Therefore, the CP based tabbing process for lead free ribbons enables to interconnect cells in c-Si PV module, without deteriorating its performance.

Magnetoresistance Effects of Magnetic Tunnel Junctions with Amorphous CoFeSiB Single and Synthetic Antiferromagnet Free Layers (비정질 CoFeSiB 단일 및 합성형 반강자성 자유층을 갖는 자기터널접합의 자기저항 효과)

  • Hwang, J.Y.;Kim, S.S.;Rhee, J.R.
    • Journal of the Korean Magnetics Society
    • /
    • v.15 no.6
    • /
    • pp.315-319
    • /
    • 2005
  • To obtain low switching field ($H_{SW}$) we introduced amorphous ferromagnetic $Co_{70.5}Fe_{4,5}Si_{15}B_{10}$ single and synthetic antiferromagnet (SAF) free layers in magnetic tunnel junctions (MTJs). The switching characteristics for MTJs with structures $Si/SiO_2/Ta$ 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) were investigated and compared to MTJs with $Co_{75}Fe_{25}$ and $Ni_{80}Fe_{20}$ free layers. CoFeSiB showed a lower saturation magnetization of $560 emu/cm^3$ and a higher anisotropy constant of $2800\;erg/cm^3$ than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the CoFeSiB single and SAF free layer MTJs, it was frond that the size dependence of the $H_{SW}$ originated from the lower $J_{ex}$ experimentally and by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. The CoFeSiB SAF structures showed lower $H_{SW}$ than that of NiFe, CoFe and CoFeSiB single structures. The CoFeSiB SAF structures were proved to be beneficial far the switching characteristics such as reducing the coercivity and increasing the sensitivity in micrometer to submicrometer-sized elements.

Bias Voltage Dependence of Magnetic Tunnel Junctions Comprising Double Barriers and CoFe/NiFeSiB/CoFe Free Layer (CoFe/NiFeSiB/CoFe 자유층을 갖는 이중장벽 자기터널접합의 바이어스전압 의존특성)

  • Lee, S.Y.;Rhee, J.R.
    • Journal of the Korean Magnetics Society
    • /
    • v.17 no.3
    • /
    • pp.120-123
    • /
    • 2007
  • The typical double-barrier magnetic tunnel junction (DMTJ) structure examined in this paper consists of a Ta 45/Ru 9.5/IrMn 10/CoFe7/$AlO_x$/free layer/AlO/CoFe 7/IrMn 10/Ru 60 (nm). The free layer consists of an $Ni_{16}Fe_{62}Si_8B_{14}$ 7 nm, $Co_{90}Fe_{10}$ (fcc) 7 nm, or CoFe $t_1$/NiFeSiB $t_2$/CoFe $t_1$ layer in which the thicknesses $t_1$ and $t_2$ are varied. The DMTJ with an NiFeSiB-free layer had a tunneling magnetoresistance (TMR) of 28%, an area-resistance product (RA) of $86\;k{\Omega}{\mu}m^2$, a coercivity ($H_c$) of 11 Oe, and an interlayer coupling field ($H_i$) of 20 Oe. To improve the TMR ratio and RA, a DMTJ comprising an amorphous NiFeSiB layer that could partially substitute for the CoFe free layer was investigated. This hybrid DMTJ had a TMR of 30%, an RA of $68\;k{\Omega}{\mu}m^2$, and a of 11 Oe, but an increased of 37 Oe. We confirmed by atomic force microscopy and transmission electron microscopy that increased as the thickness of NiFeSiB decreased. When the amorphous NiFeSiB layer was thick, it was effective in retarding the columnar growth which usually induces a wavy interface. However, if the NiFeSiB layer was thin, the roughness was increased and became large because of the magnetostatic $N{\acute{e}}el$ coupling.

Synthesis and Mechanical Properties of nc-TiN/a-Si3N4 Nanocomposite Coating Layer (나노복합체 nc-TiN/a-Si3N4 코팅막의 합성 및 기계적 성질)

  • 김광호;윤석영;김수현;이건환
    • Proceedings of the Korean Institute of Surface Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.49-49
    • /
    • 2002
  • 독립된 티타늄(Ti)과 실리콘(Si) 타켓을 사용하여 DC reactive magnetron co-sputtering 공 정으로 Ti-Si-N 코탱막을 SKD 11 합금강위에 합성하였다. 고분해능 TEM 및 XPS 분석들로부터 Ti-Si-N 코탱막은 나노미터 크기의 TiN결정체들이 비정질 Si3N4 기지에 분산된 나노복합체의 마세구조를 냐타내었다. 코탱막의 경도는 11 at.%의 Si 함량에서 39 GPa의 최 고 경도값을 나타내었고 이 경우 미셰조직은 5nm 크기의 미세한 TiN 결정이 비정절상의 기지에 균일하게 분포된 특성을 보였다 .. Ti-Si-N 박막내에 Si 함량이 증가할수록 TiN 결정 상들은 다배향성을 나타내었고 크기가 감소하였으며 비정질상에 의해 완전히 둘려싸언 형상 으로 변화하였다. 높은 Si 함량에서는 질소 소스의 부족현상에 의하여 코팅막내에서 free Si 가 나타났다. 상대습도가 증가함에 따라 Ti-Si-N 코탱막의 마찰계수와 마모량이 현저하게 감소하였다. 강재에 대한 Ti-Si-N 코팅막의 마모거동에 있어서 Si02 냐 Si(OH)2 같은 얇은 윤활막의 형성이 중요한 역할을 하는 것으로 판단되어졌다.

  • PDF

Growth of SiC film on SiNx/Si Structure (SiNx/Si 구조를 이용한 SiC 박막성장)

  • Kim, Gwang-Cheol;Park, Chan-Il;Nam, Gi-Seok;Im, Gi-Yeong
    • Korean Journal of Materials Research
    • /
    • v.10 no.4
    • /
    • pp.276-281
    • /
    • 2000
  • Silicon carbide(SiC) films were grown on modified Si(111) surface with a SiNx in the NH$_3$surrounding. Thickness of SiC films was decreased with increasing of the nitridation time. Also, voids having crystal defects were removed at interface of SiC/Si according to growth parameters. SiC films were grown on SiNx/Si substrate of 100, 300 and 500nm thickness. SiC films were deposited along [111] direction and columnar grains of SiC crystal. The void-free film was observed in the interface of SiC/SiNx. This result suggests that fabrication of SiC devices are applied to SiNx replacing silicon oxide in SOI structure.

  • PDF

Immobilization of Laccase on $SiO_2$ Nanocarriers Improves Its Stability and Reusability

  • Patel, Sanjay K.S.;Kalia, Vipin C.;Choi, Joon-Ho;Haw, Jung-Rim;Kim, In-Won;Lee, Jung Kul
    • Journal of Microbiology and Biotechnology
    • /
    • v.24 no.5
    • /
    • pp.639-647
    • /
    • 2014
  • Laccases have a broad range of industrial applications. In this study, we immobilized laccase on $SiO_2$ nanoparticles to overcome problems associated with stability and reusability of the free enzyme. Among different reagents used to functionally activate the nanoparticles, glutaraldehyde was found to be the most effective for immobilization. Optimization of the immobilization pH, temperature, enzyme loading, and incubation period led to a maximum immobilization yield of 75.8% and an immobilization efficiency of 92.9%. The optimum pH and temperature for immobilized laccase were 3.5 and $45^{\circ}C$, respectively, which differed from the values of pH 3.0 and $40^{\circ}C$ obtained for the free enzyme. Immobilized laccase retained high residual activities over a broad range of pH and temperature. The kinetic parameter $V_{max}$ was slightly reduced from 1,890 to 1,630 ${\mu}mol/min/mg$ protein, and $K_m$ was increased from 29.3 to 45.6. The thermal stability of immobilized laccase was significantly higher than that of the free enzyme, with a half-life 11- and 18-fold higher at temperatures of $50^{\circ}C$ and $60^{\circ}C$, respectively. In addition, residual activity was 82.6% after 10 cycles of use. Thus, laccase immobilized on $SiO_2$ nanoparticles functionally activated with glutaraldehyde has broad pH and temperature ranges, thermostability, and high reusability compared with the free enzyme. It constitutes a notably efficient system for biotechnological applications.

Immobilization and Performance of Penicillin G Acylase on Magnetic Ni0.7Co0.3Fe2O4@SiO2-CHO Nanocomposites

  • Lv, Zhixiang;Yu, Qingmei;Wang, Zhou;Liu, Ruijiang
    • Journal of Microbiology and Biotechnology
    • /
    • v.29 no.6
    • /
    • pp.913-922
    • /
    • 2019
  • Magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4$ nanoparticles that were prepared via the rapid combustion process were functionalized and modified to obtain magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4@SiO_2-CHO$ nanocomposites, on which penicillin G acylase (PGA) was covalently immobilized. Selections of immobilization concentration and time of fixation were explored. Catalytic performance of immobilized PGA was characterized. The free PGA had greatest activity at pH 8.0 and $45^{\circ}C$ while immobilized PGA's activities peaked at pH 7.5 and $45^{\circ}C$. Immobilized PGA had better thermal stability than free PGA at the range of $30-50^{\circ}C$ for different time intervals. The activity of free PGA would be 0 and that of immobilized PGA still retained some activities at $60^{\circ}C$ after 2 h. $V_{max}$ and $K_m$ of immobilized PGA were 1.55 mol/min and 0.15 mol/l, respectively. Free PGA's $V_{max}$ and $K_m$ separately were 0.74 mol/min and 0.028 mol/l. Immobilized PGA displayed more than 50% activity after 10 successive cycles. We concluded that immobilized PGA with magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4@SiO_2-CHO$ nanocomposites could become a novel example for the immobilization of other amidohydrolases.

Effect of Heat Treatment on Microstructure and Mechanical Properties of Al-Zn-Mg-Cu-Si Sintered Alloys with and Without High-energy Ball Milling (Al-Zn-Mg-Cu-Si 소결합금의 미세조직과 기계적 특성에 미치는 열처리의 영향)

  • Junho Lee;Seonghyun Park;Sang-Hwa Lee;Seung Bae Son;Seok-Jae Lee;Jae-Gil Jung
    • Journal of Powder Materials
    • /
    • v.30 no.6
    • /
    • pp.470-477
    • /
    • 2023
  • The effects of annealing on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Si alloys fabricated by high-energy ball milling (HEBM) and spark plasma sintering (SPS) were investigated. The HEBM-free sintered alloy primarily contained Mg2Si, Q-AlCuMgSi, and Si phases. Meanwhile, the HEBM-sintered alloy contains Mg-free Si and θ-Al2Cu phases due to the formation of MgO, which causes Mg depletion in the Al matrix. Annealing without and with HEBM at 500℃ causes partial dissolution and coarsening of the Q-AlCuMgSi and Mg2Si phases in the alloy and dissolution of the θ-Al2Cu phase in the alloy, respectively. In both alloys, a thermally stable α-AlFeSi phase was formed after long-term heat treatment. The grain size of the sintered alloys with and without HEBM increased from 0.5 to 1.0 ㎛ and from 2.9 to 6.3 ㎛, respectively. The hardness of the sintered alloy increases after annealing for 1 h but decreases significantly after 24 h of annealing. Extending the annealing time to 168 h improved the hardness of the alloy without HEBM but had little effect on the alloy with HEBM. The relationship between the microstructural factors and the hardness of the sintered and annealed alloys is discussed.