• 제목/요약/키워드: Metal oxide addition

검색결과 302건 처리시간 0.024초

High Performance Current Sensing Circuit for Current-Mode DC-DC Buck Converter

  • Jin, Hai-Feng;Piao, Hua-Lan;Cui, Zhi-Yuan;Kim, Nam-Soo
    • Transactions on Electrical and Electronic Materials
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    • 제11권1호
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    • pp.24-28
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    • 2010
  • A simulation study of a current-mode direct current (DC)-DC buck converter is presented in this paper. The converter, with a fully integrated power module, is implemented by using sense method metal-oxide-semiconductor field-effect transistor (MOSFET) and bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. When the MOSFET is used in a current sensor, the sensed inductor current with an internal ramp signal can be used for feedback control. In addition, the BiCMOS technology is applied in the converter for an accurate current sensing and a low power consumption. The DC-DC converter is designed using the standard $0.35\;{\mu}m$ CMOS process. An off-chip LC filter is designed with an inductance of 1 mH and a capacitance of 12.5 nF. The simulation results show that the error between the sensing signal and the inductor current can be controlled to be within 3%. The characteristics of the error amplification and output ripple are much improved, as compared to converters using conventional CMOS circuits.

저온소성 기판과 Cu와의 동시소성에 미치는 CuO의 첨가효과 (The Influence of CuO on Bonding Behaviors of Low-Firing-Substrate and Cu Conductor)

  • 박정현;이상진
    • 한국세라믹학회지
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    • 제31권4호
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    • pp.381-388
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    • 1994
  • A new process which co-fires the low-firing-substrate and copper conductor was studied to achieve good bond strength and low sheet resistance of conductor. Cupric oxide is used as the precursor of conductive material in the new method and the firing atmosphere of the new process is changed sequently in air H2N2. The addition of cupric oxide and variations of firing atmosphere permited complete binder-burnout in comparison with the conventional method and contributed to the improvement of resistance and bonding behaviors. The potimum conditions of this experiment to obtain the satisfactory resistance and bond strength are as follows (binder-burnout temperature in air; 55$0^{\circ}C$, reducing temperature in H2; 40$0^{\circ}C$ for 30 min, ratio of copper and cupric oxide; 60:40~30:70 wt%). The bonding mechanism between the substrate and metal was explained by metal diffusion layer in the interface and the bond strength mainly depended on the stress caused by the difference of shrinkage and thermal expansion coefficient between the substrate and metal.

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도재주조용 합금에 있어서 알루미륨 첨가에 따른 metal-ceramic과의 결합력 증진에 관한 연구 (A Study on Improvement of Metal-Ceramic Bonding Strength by Addition of Aluminum to Casting Metal Alloy)

  • 이재원;민병국;한민수
    • 대한치과기공학회지
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    • 제23권2호
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    • pp.161-170
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    • 2002
  • The Purpose of this study was to investigate the chemically improvement of metal-ceramics bond strength in the course of recasting Ni-Cr metal composite system with 10wt.%, 20wt.% and 30wt.% aluminum respectively. We have tested the bond strength, micro-structure, chemical composition of each metal composites and metal- ceramic bond interfaces by 3-point bending strength tester, SEM and EDS. We have made the conclusions through this study as follow: 1. The most suitable amount of aluminum to the Ni-Cr metal composite recasting is 20wt. % for improving metal-ceramics bond strength with debonding strength value of 49.54 kgf/mm2. 2. The aluminum must be changed to small spread alumina like phases and second aluminum-metal composites phases in the morphology of Ni-Cr metal composite system by adding during it's casting. These second phases have inclined functional oxide phases mixed with metal elements and they must take roll to improvement of metal-ceramics bond strength. 3. In the case of 30wt.% aluminum appended to Ni-Cr metal composite system, an excess of second inclined functional oxide phases produce cracks and spalling of them apart from it's base material. It must be a important factor of reduction of metal-ceramics bond strength.

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고성능 유연 투명전극용 SiO2 기반 비대칭 다층 박막의 특성 (Characteristics of SiO2 Based Asymmetric Multilayer Thin Films for High Performance Flexible Transparent Electrodes)

  • 정지원;공헌;이현용
    • 한국전기전자재료학회논문지
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    • 제33권1호
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    • pp.25-30
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    • 2020
  • Oxide (SiO2)/Metal(Ag)/Oxide(SiO2, ITO, ZnO) multilayer films were fabricated using a magnetron sputtering technique at room temperature on Si (p-type, 100) and a glass substrate. The electrical and optical properties of the asymmetric multilayer films depended on the thickness of the mid-layer film and the type of oxide in the bottom layer. As the metal layer becomes thicker, the sheet resistance decreases. However, the transmittance decreases when the metal layer exceeds a threshold thickness of approximately 10~12 nm. In addition, the sheet resistance and transmittance change according to the type of oxide in the bottom layer. If the oxide has a large resistivity, the overall sheet resistance increases. In addition, the anti-reflection effect changes according to the refractive index of the oxide material. The optical and electrical properties of multilayer films were investigated using an ultraviolet visible (UV-Vis) spectrophotometer and a 4-point probe, respectively. The optimum structure is SiO2 (30 nm)/Ag (10 nm)/ZnO (30 nm) multilayer, with the highest FOM value of 7.7×10-3 Ω-1.

Sr-doped AlOx gate dielectrics enabling high-performance flexible transparent thin film transistors by sol-gel process

  • Kim, Jaeyoung;Choi, Seungbeom;Kim, Yong-Hoon
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.301.2-301.2
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    • 2016
  • Metal-oxide thin-film transistors (TFTs) have gained a considerable interest in transparent electronics owing to their high optical transparency and outstanding electrical performance even in an amorphous state. Also, these metal-oxide materials can be solution-processed at a low temperature by using deep ultraviolet (DUV) induced photochemical activation allowing facile integration on flexible substrates [1]. In addition, high-dielectric constant (k) inorganic gate dielectrics are also of a great interest as a key element to lower the operating voltage and as well as the formation of coherent interface with the oxide semiconductors, which may lead to a considerable improvement in the TFT performance. In this study, we investigated the electrical properties of solution-processed high-k strontium-doped AlOx (Sr-AlOx) gate dielectrics. Using the Sr-AlOx as a gate dielectric, indium-gallium-zinc oxide (IGZO) TFTs were fabricated and their electrical properties are analyzed. We demonstrate IGZO TFTs with a 10-nm-thick Sr-AlOx gate dielectric which can be operated at a low voltage (~5 V).

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Fabrication of metal nanodots and nanowires by atomic force microscopy nanomachining

  • Lin, Heh-Nan
    • 정보저장시스템학회논문집
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    • 제3권1호
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    • pp.43-46
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    • 2007
  • The fabrication of metal nanostructures by a combination of atomic force microscopy nanomachining on a thin polymer resist, metal coating and lift-off is reported. Nanodots with sizes and nanowires with widths ranging between 50 and 100 nm have been successfully created. The present work exemplifies the feasibility and effectiveness of using a single-layer resist in comparison with a two-layer resist. In addition, the localized surface plasmon resonance peaks of the metal nanostructures have been measured and the selective growths of zinc oxide nanowires on the metal nanostructures are demonstrated.

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Nanopatterning of Self-assembled Transition Metal Nanostructures on Oxide Support for Nanocatalysts

  • Van, Trong Nghia;Park, Jeong-Young
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.211-211
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    • 2011
  • Nanostructures, with a diversity of shapes, built on substrates have been developed within many research areas. Lithography is one powerful, but complex, technique to make structures at the nanometer scale, such as platinum nanowires for studying CO catalytic reactions [1], or aluminum nanodisks for studying the plasmon effect [2]. In this work, we approach a facile method to construct nanostructures using noble metals on a titania thin film by using self-assembled structures as a pattern. Here, a large-scale silica monolayer is transferred to the titania thin film substrates using a Langmuir-Blodgett trough, followed by the deposition of a thin transition metal layer. Owing to the hexagonal close-packed structure of the silica monolayer, we would obtain a metal nanostructure that includes separated metallic triangles (islands) after removing the patterning silica beads. This nanostructure can be employed to investigate the role of metal-oxide interfaces in CO catalytic reactions by changing the patterning silica particles with different sizes or by replacing the oxide support. The morphology and chemical composition of the structure can be characterized by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. In addition, we modify these islands to a connected island structure by reducing the silica size of the patterning monolayer, which is utilized to generating hot electron flow based on the localized surface plasmon resonance effect of the metal nanostructures.

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고온 노출 니켈기 초내열합금 터빈 블레이드의 Cr/Ti/Al 성분이 고온 산화에 미치는 영향 (Effect of Cr/Ti/Al Elements on High Temperature Oxidation Behavior of a Ni-Based Superalloy with Thermal Exposure)

  • 최병학;한성희;김대현;안종기;이재현;최광수
    • 한국재료학회지
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    • 제33권2호
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    • pp.77-86
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    • 2023
  • High-temperature oxidation of a Ni-based superalloy was analyzed with samples taken from gas turbine blades, where the samples were heat-treated and thermally exposed. The effect of Cr/Ti/Al elements in the alloy on high temperature oxidation was investigated using an optical microscope, SEM/EDS, and TEM. A high-Cr/high-Ti oxide layer was formed on the blade surface under the heat-treated state considered to be the initial stage of high-temperature oxidation. In addition, a PFZ (γ' precipitate free zone) accompanied by Cr carbide of Cr23C6 and high Cr-Co phase as a kind of TCP precipitation was formed under the surface layer. Pits of several ㎛ depth containing high-Al content oxide was observed at the boundary between the oxide layer and PFZ. However, high temperature oxidation formed on the thermally exposed blade surface consisted of the following steps: ① Ti-oxide formation in the center of the oxide layer, ② Cr-oxide formation surrounding the inner oxide layer, and ③ Al-oxide formation in the pits directly under the Cr oxide layer. It is estimated that the Cr content of Ni-based superalloys improves the oxidation resistance of the alloy by forming dense oxide layer, but produced the σ or µ phase of TCP precipitation with the high-Cr component resulting in material brittleness.

전기방사를 이용한 슈퍼캐퍼시터용 금속산화물/탄소나노섬유 복합체 (Electrospun Metal Oxide/Carbon Nanofiber Composite Electrode for Supercapacitor Application)

  • 양갑승;김보혜
    • 공업화학
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    • 제26권3호
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    • pp.239-246
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    • 2015
  • 나노 탄소재료를 복합화하면 기존 재료의 특성을 유지하면서 그 효율을 극대화할 수 있다. 여기에 이종원소를 부가하면 전기화학적인 특성이 디자인되므로, 나노 탄소재료의 복합화를 통해 한 종류의 나노 재료로부터 여러 강점을 얻을 수 있다. 특히 탄소나노섬유와 금속산화물을 복합화하면 탄소나노섬유의 전기이중층 뿐만 아니라 금속산화물의 산화 환원 반응을 이용하여 비축전 용량, 고율 특성, 수명 특성이 향상되고 높은 수준의 출력밀도가 유지되는 고용량 슈퍼 캐퍼시터용 전극 소재를 개발할 수 있다. 본 총설에서는 탄소의 고출력특성과 금속산화물의 고에너지 특성이 동시에 발현되는 금속산화물계 탄소나노섬유복합체의 제법과 응용에 대한 최신연구를 다루도록 하겠다.

전기접점용 Ag-CdO합금의 물성에 미치는 Mm(misch metal) 첨가의 영향 (Effects of Mm(misch metal) Addition on The Property of Ag-CdO alloys for Electrical Contactor)

  • 박수동;이희웅;김봉서;김병걸;송재영
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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    • pp.34-37
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    • 2004
  • It is well known that Ag-CdO alloy for electrical contactor has been widely used in weak or middle electric current field. But it is necessary to decrease Cd contents without decrease of contactor property because Cd is harmful to human body. The present work has been carried out to investigate effects of Mm (misch metal) addition on the property of Ag-CdO alloy for electrical contactor. As the results of present works, hardness and strength was improved and arc resistance was improved, also, in spite of decrease Cd contents by the Mm addition. It was estimated that Ag-oxide particle was refined by Mm addition.

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