• Title/Summary/Keyword: 전류응력

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A study on the effect of additive on the properties of Ni-Co plating surface (Ni-Co 합금액에서 첨가제가 도금피막에 미치는 영향에 관한연구)

  • Lee, Hong-Gi;Jeon, Jun-Mi;Heo, Jin-Yeong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.11a
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    • pp.260-260
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    • 2015
  • 본 연구는 높은 인장력, 좋은 내마모성, 열전도성, 경도와 자성 등의 특성을 가진 니켈 코발트 합금 도금액 개발에 있어 첨가제를 첨가하여 피막 특성을 관찰하였다. Ni-Co 합금 도금액 개발을 위해 니켈 염으로 썰파민산 니켈 혹은 황산 니켈을 이용하여 황산코발트를 50g/L 혼합하여 $5A/dm^2$의 전류를 가할 경우 약 $40{\mu}m/hr$의 도금속도를 나타내었으며 코발트의 공석량은 50~55wt.% 였다. 도금액에 Leveler 및 wetter를 첨가하여 도금피막 특성을 관찰하였으며 이때 도금피막에 작용하는 내부응력을 관찰한 결과 썰파민산 니켈을 사용한 도금액의 내부응력이 낮음을 확인할 수 있었다.

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nBn Based InAs/GaSb Type II Superlattice Detectors with an N-type Barrier Doping for the Long Wave Infrared Detection (InAs/GaSb 제2형 응력 초격자 nBn 장적외선 검출소자 설계, 제작 및 특성평가)

  • Kim, Ha Sul;Lee, Hun;Klein, Brianna;Gautam, Nutan;Plis, Elena A.;Myers, Stephen;Krishna, Sanjay
    • Journal of the Korean Vacuum Society
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    • v.22 no.6
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    • pp.327-334
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    • 2013
  • Long-wave infrared detectors using the type-II InAs/GaSb strained superlattice (T2SL) material system with the nBn structure were designed and fabricated. The band gap energy of the T2SL material was calculated as a function of the thickness of the InAs and GaSb layers by the Kronig-Penney model. Growth of the barrier material ($Al_{0.2}Ga_{0.8}Sb$) incorporated Te doping to reduce the dark current. The full width at half maximum (FWHM) of the $1^{st}$ satellite superlattice peak from the X-ray diffraction was around 45 arcsec. The cutoff wavelength of the fabricated device was ${\sim}10.2{\mu}m$ (0.12 eV) at 80 K while under an applied bias of -1.4 V. The measured activation energy of the device was ~0.128 eV. The dark current density was shown to be $1.0{\times}10^{-2}A/cm^2$ at 80 K and with a bias -1.5 V. The responsivity was 0.58 A/W at $7.5{\mu}m$ at 80 K and with a bias of -1.5 V.

The Static Overload Effect Estimations on Fatigue Strength by The Measurement of Local Strain Variation at The Weldment Toe (용접 토우부의 국부적 변형률 측정을 통한 용접부의 정적 과하중에 따른 피로강도의 변화 평가)

  • Lee, Hyun-Woo;Kim, Ju-Hwan;Kim, Hyun-Jae
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.6
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    • pp.59-66
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    • 2001
  • Fatigue strength of the welding structure is governed by the residual stress at the weldment toe and static tensile overloads were known as relieving the residual stresses. In this study, static tensile overloads were applied to the welding structures which caused the relief of residual stresses. The amount of residual stress relief was found as proportional to the change of fatigue limit at the given conditions. Based on the fact of the proportionality between the change of fatigue limit and that of residual stress, simple measurement technique is proposed. Modified stress-life curves base on proposed technique gave good agreement with test results.

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Characteristics of ER Fluids with Different Electrode Gaps and Materials (전극재질 및 간긍에 따른 ER유체의 특성실험)

  • 최승복
    • The Korean Journal of Rheology
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    • v.10 no.3
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    • pp.165-172
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    • 1998
  • 본논문에서는 전기장 부하에 따라 유동성질이 변화하는 ER유체의 빙햄특성을 실험 적으로 연구하였다. 특히 ER유체의 빙행특성에 영향을 주는 여러인자중 전극 간격 및 재질 에 따른 ER유체의 항복전단응력과 전류밀도의 변화를 온도에 따라 고찰하였다. 이를 위하 여 전극 간격을 가변시킬수 있는 전기 점도계를 세가지 재질로 자체 제작하였다. 전극간격 은 0.75 mm, 1.00mm 및 1.25 mm 로 설정하였으며 전극 재질은 스테인레스 스텔, 동 그리 고 기계구조용 탄소강(SMS45C)을 사용했다. 한편 실험에 사용된 ER유체는 자체 조성한 수 계 ER유체인 ERF-1과 외국의 우수하다고 알려진 비수계 ER유체인 ERF-2 두가지를 선택 하였다. 실험은 $25^{\circ}C$와 7$0^{\circ}C$ 및 10$0^{\circ}C$에서 수행하였으며 전기장은 0-4kV/mm 범위에서 온 도 및 ER유체의 종류에 따라 부하 가능한 전압까지 공급하였다. 전단변형률 50, 100, 150, 200, 400, 600, 800, 1000 및 1200 s-1에서 얻은 전단응력 실험결과로부터 최소오차선형법을 이용하여 전단변형률 영에서 동적 항복전단응력 값을 도출하였으며 그결과로부터 전극 간격 및 재질에 따른 ER효과의 변화를 고찰하였다. 또한 상온과 10$0^{\circ}C$에서 4kV/mm의 전기장을 부하하여 전기장에대한 ER유체의 응답특성을 실험을 수행했다.

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Temperature Properties about SMD Inductor Core of Union Type (일체형 SMD Inductor 코어에 대한 온도 특성)

  • Kim, Ki-Joon
    • 전자공학회논문지 IE
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    • v.47 no.2
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    • pp.32-37
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    • 2010
  • In this study, to develop union type SMD inductor core needs to have the desire of super miniaturization and high reliability, it analyzed temperature properties due to electric power value. As the temperature of electronic parts rise, it bring to technical obstacles that parts can not normal operation, it reduce the span of life to raise the fault ratio. Also, it impact to the parts by heat change power and expansive power, it can not behave exactly, and it have an effect on reliability. It measured the difference value between conditional temperature and parts temperature to union type SMD inductor core. As the results of simulation using D.C. current and resistor($R_dc$), it obtained the excellent regular current values at rising temperature of 40[$^{\circ}C$].

Research trends in the field of spot welding (점 용접의 연구동향)

  • 이강용
    • Journal of the korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.13-17
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    • 1989
  • 전기저항을 이용하여 두께가 1-7mm(0.03-0.27in)의 얇은 구조물을 국부적으로 융착시켜 접합하는 점용접은 자동차 및 항공기 부품산업에 활용도가 높아지고 있다. 구조물 접합시 점 용접은 너깃 주위의 열영향부에 잔류응력이 발생하므로 정적강도와 피로강도를 저하시키려는 원인이 되고 있다. 따라서 강도의 저하를 방지하기 위하여 용접시간, 용접전류량, 용접 가압력 등에 대한 최적 용접조건을 설정하기 위한 연구가 많이 진행중에 있다.

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Continuous Surface Treatment of Superconductive Wire Materials with High Uniformity (고균일 초전도 선재 연속표면처리 기술)

  • Ham, Byeong-Cheol;Lee, Ho-Nyeon;Kim, Hyeon-Jong;Heo, Jin-Yeong;Lee, Hong-Gi
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2014.11a
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    • pp.277-277
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    • 2014
  • 최근 중요성이 날로 증대되고 있는 초전도 선재의 구리도금막의 두께 균일도 개선을 위하여 선재간 간격, 첨가제 종류 및 농도 변화 및 압축응력 인가의 3가지 관점에서 연구를 진행하였고, 전류밀도를 증가시켜 생산성을 제고하면서 두께균일도를 개선할 수 있음을 확인하였다.

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Study of Stress Changes in Nanocrystalline CoW Thin/Thick Film Alloys Eletrodeposited from Citrate Baths (Citrate Baths로부터 전기도금된 나노결정립 CoW 합금 박막/후막의 응력변화에 대한 연구)

  • Cho, Ik-Jong;Park, Deok-Yong;Ihn, Hyun-Man
    • Journal of the Korean Electrochemical Society
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    • v.9 no.4
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    • pp.141-150
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    • 2006
  • Nanocrystalline CoW thin/thick film alloys were electodeposited from citrate baths to investigate the influences of metal ion concentration, current density and solution pH on chemical composition, current efficiency, residual stress, surface morphology, and microstructure of the film. Deposit W (tungsten) content in CoW thin/thick film increased with increasing W ion concentration, current density, and solution pH in the plating bath. It was observed that residual stress in CoW thin/thick film decreased with increasing W ion concentration and solution pH. CoW thin film exhibited mixed phases of hop Co [(100) and (002)] and hcp $Co_3W$ [(002) and (201)] at W ion concentration with 0.02 to 0.08 M. The microstructure of CoW thin film at W ion concentration of 0.1 to 0.2 M was close to amorphous phase. The dominant phases were found to be hop Co (002) and hop $Co_3W$ [(200), (002) and (201)] at the current densities of 5, 10, 25, and $100mA{\cdot}cm^{-2}$ CoW thin film at the current densities of 50 and $75mA{\cdot}cm^{-2}$ was close to amorphous phase. At solution pH 8.7, CoW thin film exhibited hcp Co (002) and hop $Co_3W$ [(200), (002) and (201)]. Below solution pH 8.7, CoW thin film exhibited amorphous microstructure. The optimum electrodeposition conditions for CoW thin/thick film were found to be W ion concentration of 0.08 M, current density of $10mA{\cdot}cm^{-2}$, and solution pH 8.7.

Corrosion-bond Strength Evaluation in OPC and Slag Concrete using Accelerated Corrosion Test (촉진부식실험을 이용한 OPC 및 슬래그 콘크리트의 부식-부착강도 평가)

  • Sang-Jin Oh;Hyeon-Woo Lee;Seung-Jun Kwon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.12 no.1
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    • pp.1-7
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    • 2024
  • Concrete, as a porous construction material, permits chloride penetration from outside, which yields corrosion in embedded steel. In the study, an accelerated corrosion technique (ICM: Impressed current method) was adopted for rapid corrosion formation with 10 Volt of potential, and corrosion amou nt was controlled u p to 10.0 %. Corrosion amou nt had a linear relationship with cumulative corrosion current and increased with a quadratic function of accelerating period due to cracking. Regarding bond strength test, OPC concrete showed rapid drop of bond strength over 3.0 % of corrosion weight ratio, however slag concrete with 30 % replacement ratio showed a level of 51.4~71.6 % of corrosion ratio to OPC concrete with keeping residual bond strength.

Technology of Non-destructive Stress Measurement in Spot Welded Joint using ESPI Method (ESPI법에 의한 스폿 용접부의 비파괴적 응력측정 기술)

  • 김덕중;국정한;오세용;김봉중;유원일;김영호
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.1 no.1
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    • pp.23-26
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    • 2000
  • In spot welded joint. Electronic Speckle Pattern Interferometry(ESPI) method using the Model 95 Ar laser a video system and an image processor was applied to measure the stress Unlike traditional strain gauges or Moire method, ESPI method has no special surface preparation or attachments and can be measured in-plane displacement with non-contact and real time. In this experiment, specimens are loaded in parallel with a load cell. The specimens are made of the cold rolled steel sheet with 1mm thickness, are attached strain. gauges. This study Provides an example of how ESPI has been used to measure stress and strain inspecimen. The results measured by ESPI are compared with the data which was measured by strain gauge method under tensile testing.

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