• Title/Summary/Keyword: physical contacts

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Plasma Treatments to Forming Metal Contacts in Graphene FET

  • Choi, Min-Sup;Lee, Seung-Hwan;Lim, Yeong-Dae;Yoo, Won-Jong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.121-121
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    • 2011
  • Graphene formed by chemical vapor deposition was exposed to the various plasmas of Ar, O2, N2, and H2 to examine its effects on the bonding properties of graphene to metal. Upon the Ar plasma exposure of patterned graphene, the subsequently deposited metal electrodes remained intact, enabling successful fabrication of field effect transistor (FET) arrays. The effects of enhancing adhesion between graphene and metals were more evident from O2 plasmas than Ar, N2, and H2 plasmas, suggesting that chemical reaction of O radicals induces hydrophilic property of graphene more effectively than chemical reaction of H and N radicals and physical bombardment of Ar ions. From the electrical measurements (drain current vs. gate voltage) of field effect transistors before and after Ar plasma exposure, it was confirmed that the plasma treatment is very effective in controlling bonding properties of graphene to metals accurately without requiring buffer layers.

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Thermal Property of Mo-5~20 wt%. Cu Alloys Synthesized by Planetary Ball Milling and Spark Plasma Sintering Method (유성볼밀링 및 스파크 플라즈마 소결법으로 제조한 Mo-5~20 wt%. Cu 합금의 열적 특성)

  • Lee, Han-Chan;Moon, Kyoung-Il;Shin, Paik-Kyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.8
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    • pp.516-521
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    • 2016
  • Mo-Cu alloys have been widely used for heat sink materials, vacuum technology, automobile, and many other applications due to their excellent physical and electric properties. Especially, Mo-Cu composites with 5 ~ 20 wt.% copper are widely used for the heavy duty service contacts due to their excellent properties like low coefficient of thermal expansion, wear resistance, high temperature strength, and prominent electrical and thermal conductivity. In most of the applications, highly-dense Mo-Cu materials with homogeneous microstructure are required for better performance. In this study, Mo-Cu alloys were prepared by PBM (planetary ball milling) and SPS (spark plasma sintering). The effect of Cu with contents of 5~20 wt.% on the microstructure and thermal properties of Mo-Cu alloys was investigated.

Natural Education Programs for Personalization of Environment : - Cases of Michigan 4-H Children's Garden, Binder Park Zoo, and Natural Education Programs of National Parks in the United States (자기환경화를 가능하게 하는 자연교육 프로그램 - 미국의 미시건 4-H 어린이 정원, 바인더 파크 동물원 및 국립공원 사례를 중심으로)

  • 이선경;김상윤;윤여창
    • Hwankyungkyoyuk
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    • v.11 no.2
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    • pp.102-117
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    • 1998
  • Responsible environmental behavior of Youths who will live in the 21C needs the ‘Personalization of Environment’, which means the process or the result of awareness to the non-personal environment as the personal environment to show the responsible environmental behaviors through the intended physical and psychological contacts to environment. This study intended to analyze various programs of national parks, zoo, children's garden and Project Learning Tree in the United States and to discuss the possibility of ‘personalization of environment’ and implication for environmental education of Korea. Literature review, field trips, personal interviews and internet searches were used to collect information and data. Programs of North Cascade National Park, Mt. Rainier National Park and 4-H Children's Garden in Michigan State University showed the cases of direct personalization of environment focusing on the direct contact with nature. The programs of Binder Park Zoo in Battle Creek and Project Learning Tree showed the possibilities of indirect personalization of environment forming meaningful relationships with nature through various indirect activities. It is suggested that various natural education programs in Unites States make nature and places meaningful for the people and it needs to be applied for the environmental education programs in Korea.

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A Study on the Thermal and Electrical Properties of Fabricated Mo-Cu Alloy by Spark Plasma Sintering Method (방전 플라즈마 소결법으로 제작한 Mo-Cu 합금의 열적, 전기적 특성)

  • Lee, Han-Chan;Lee, Boong-Joo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.11
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    • pp.1600-1604
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    • 2017
  • Mo-Cu alloys have been widely used for heat sink materials, vacuum technology, automobile and many other applications due to their excellent physical and electronic properties. Especially, Mo-Cu composites with 5~20 wt% copper are widely used for the heavy duty service contacts due to their excellent properties like low coefficient of thermal expansion, wear resistance, high temperature strength and prominent electrical and thermal conductivity. In most of the applications, high dense Mo-Cu materials with homogeneous microstructure are required for high performance, which has led in turn to attempts to prepare ultra-fine and well-dispersed Mo-Cu powders in different ways, such as spray drying and reduction process, electroless plating technique, mechanical alloying process and gelatification-reduction process. However, most of these methods were accomplished at high temperature (typically degree), resulting in undesirable growth of large Cu phases; furthermore, these methods usually require complicated experimental facilities and procedure. In this study, Mo-Cu alloying were prepared by planetary ball milling (PBM) and spark plasma sintering (SPS) and the effect of Cu with contents of 5~20 wt% on the microstructure and properties of Mo-Cu alloy has been investigated.

Experimental Verification on Factors Affecting Core Resistivity Measurements (코어 비저항 측정에 미치는 영향요소에 대한 실험적 고찰)

  • Kim, Yeong Hwa;Choe, Ye Gwon
    • Journal of the Korean Geophysical Society
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    • v.2 no.3
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    • pp.225-233
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    • 1999
  • Electrical resistivity of a rock-sample is dependant on not only formation factor of rock itself but also many parameters such as fluid type, measuring device, temperature, water saturation, electrical contact between electrode and core section, induced polarization, and frequency of electric source. In this study, we attempt to verify various affecting factors in core resistivity measurements and to find a better environment for core resistivity measurement. Particularly great attention has been paid to understanding the effects of temperature, water saturation, contact condition between sample and electrodes, and frequency of electric source. Precise measurement of resistivity can be achieved by utilizing silver paste for better contacts, taping samples for constant moisture contents, and using time-series resistivity data.

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Electrochemical and Cavitation Characteristics of Al Thermal Spray Coating with F-Si Sealing (알루미늄 용사코팅의 불소실리콘 봉공재 적용에 따른 전기화학적 및 캐비테이션 특성 평가)

  • Han, Min-Su;Lee, Seung-Jun;Jang, Seok-Ki;Kim, Seong-Jong
    • Corrosion Science and Technology
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    • v.9 no.6
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    • pp.317-324
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    • 2010
  • Marine transportation by ships is characterized by remote, large-volume and lower rates than the others carry system. Ships account for over 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. The construction of larger and faster ships has brought about many problems such as cavitations and erosion corrosion. Cavitations and erosion corrosion make damages on materials and leads to break down members due to continuous physical contacts with shock waves and fluids from the generation and extinction of air bubbles in sea water vortex. The steel used for ship constructions was spray-coated with Al wire, and additionally sealed with fluorine silicone sealing material. Results of experiment, corrosion resistance of sealed thermal spray coating was improved, however in cavitation resistance, the large effect was not appeared. Accordingly, this study applied for thermal spray coating to provide better electrochemical characteristics and corrosion resistance in marine environment.

Hall Effect of FeSi$_2$ Thin Film by Magnetic Field (FeSi$_2$박막 흘 효과의 자계의존성)

  • 이우선;김형곤;김남오;서용진
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.234-237
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    • 2001
  • FeSi$_2$/Si Layer were grown using FeSi$_2$, Si wafer by the chemical transport reaction method. The directoptical energy gap was found to be 0.871ev at 300 K. The Hall effect is a physical effect arising in matter carrying electric current in the presence of a magnetic field. The effect is named after the American physicist E. H. Hall, who discovered it in 1879. In this paper, we study electrical properties of FeSi$_2$/Si layer And then we measured Hall coefficient Hall mobility, carrier density and Hall voltage according to variation magnetic field and temperature, Because of important Part for it application Various phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

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Hall Effect of $FeSi_2$ Thin Film by Temperature ($FeSi_2$박막 홀 효과의 온도의존성)

  • 이우선;김형곤;김남오;정헌상
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.230-233
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    • 2001
  • FeSi$_2$ Layer were grown using FeSi$_2$, Si wafer by the chemical transport reaction method. The directoptical energy gap was found to be 0.87leV at 300 K. The Hall effect is a Physical effect arising in matter carrying electric current in the presence of a magnetic field. The effect is named after the American physicist E.H. Hall, who discovered it in 1879. In this paper, we study electrical properties of FeSi$_2$/Si layer. And then we measured Hall coefficient Hall mobility, carrier density and Hall voltage according to variation magnetic field and temperature, Because of important part for it application various phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

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Countermeasures to prevent contact between phases on overhead lines (가공송전선로 상(相)간 혼촉으로 인한 고장 예방 대책)

  • Park, Yoon-Seok;Kim, Yong-Rak;Kim, Ho-Ki;Kim, Won-Jin;Choi, Jin-Sung
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.109-110
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    • 2007
  • Most transmission lines pass through mountainous terrain and deep valleys, to avoid populated areas. Accordingly, the impact of climate changes, environmental conditions and system expansion have caused an increase in transmission line system fault rates. KEPCO has developed and applied phase-spacers to reduce contact faults between phases. Contact between phases represented 9% of total line faults before the devices were installed. Phase-spacers have reduced faults by up to 3.4% since the phase-spacers were installed in 2005. Also, recently developed devices provide additional economic benefits as they cost about a third of the price as similar devices introduced in foreign countries. Phase-spacers are an effective way to prevent phase contact accidents by maintaining physical space between phases. These spacers will be implemented in areas where contacts are likely to occur. They are expected to reduce accident rates and improve power quality.

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A study on the corporality in the film Avatar (영화 <아바타>에 나타난 육체성 연구)

  • Kim, Ho Young
    • Cross-Cultural Studies
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    • v.29
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    • pp.233-256
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    • 2012
  • This paper aims to look into various symbolic meanings of the body shown in the film, Avatar (2009, James Cameron), and to ponder over a variety of media strategies carried by the pursuit of the corporality shown in this film. In a nutshell, the body in Avatar is a symbol of primitiveness rather than civilization, and the body language is a fundamental and effective means of communication much better than verbal language. A variety of physical contacts that appeared in many scenes of the movie emphasizes the role of the body as a means of real communication. Also, in the composition of the film dominated by the confrontation of civilization, numerous creatures in the planet Pandora with a variety of colors as well as a number of agencies and large body sizes express primitive richness. The narrative of the film telling the story of a 'moving' body ultimately emphasizes the superiority of the body with respect to consciousness, unlike the narrative of conventional movies dealing with the problems of the body. In addition, the corporality pursued by this film implies several important media strategies. It may reveal a self-reflection of the material civilization and the imperialism, or, on the contrary, an attempt to conceal or dilute them. It may also represent a self-reflection of the overdeveloped media technology, or simply the dilution of it. Finally, it may be an attempt to recover the feeling of "presence", not fully supported by the 3D technology, by the identification of the spectator's body and the character's body.