• 전자공학회논문지A
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• 제33A권7호
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• pp.162-170
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• 1996

A breakdown model of gate oxides under constant current stresses is proposed. This model directly relates the oxide lifetime to the stress current density, and includes statistical nature of oxide breakdown using the concept of "effective oxide thinning". It is shown tha this model can reliably predict the TDDB characteristics for any current stress levels and oxide areas.

• Tribology and Lubricants
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• 제18권1호
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• pp.16-23
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• 2002

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of ER electrode distance. From the experimental results the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also tile compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, tile yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.138-145
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• 2001

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of compressing ER electrode. From the experimental results, the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also the compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, the yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.

• 한국해양공학회지
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• 제18권5호
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• pp.50-56
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• 2004

This study is on the constant-current stress corrosion test, related to the load stress, in both the welded and non-welded zones of high tensile strength steel that is used for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed general corrosion and narrow pitting, and the pitting was increased with load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel, used for natural gas transmission specimens, were decreased rapidly, and the average relative electrode potential was higher and the average relative current was lower in welded zone, compared to base metal. The average relative electrode potential was decreased with load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone, compared to base metal, and the corrosion rate was decreased by increasing the load stress.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.401-407
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• 2004

This study is on the constant-current stress corrosion test related to the load stress in welded zone and non-welded zone of high tensile strength steel for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed global corrosion and narrow pitting, and the pitting was increased by increasing the load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel for natural gas transmission specimens was decreased suddenly, and the average relative electrode potential was higher and the average relative current was lower in welded zone than base metal. and the average relative electrode potential was decreased by increasing the load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone than base metal, and the corrosion rate was decreased by increasing the load stress.

• 한국재료학회지
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• 제12권2호
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• pp.103-111
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• 2002

The thermally insulated underground pipelines have been used for district heating system. The sensor wire embedded in the insulation was used for monitoring the insulating resistance between the sensor wire and the pipe. The resistance measurement system detects corrosion of steel pipe under insulation. The corrosion and stress corrosion cracking(SCC) characteristics of sensor wire in synthetic ground water were investigated using the electrochemical methods and constant load SCC tests. The polarization tests were used to study the electrochemical behavior of sensor wire. The sensor wire was passivated at temperatures ranging from 25 to $95^{\circ}C$. However, the applied sensing current larger than passive current resulted in breakdown of passive film. The constant load SCC tests were performed to investigate the effects of applied current and load on the fracture behavior. Stress-corrosion cracks initiated at pits that were produced by sensing current. The growth of the pit involves a tunnelling mechanism, which leads to ductile fracture.

• 전자공학회논문지
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• 제50권8호
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• pp.285-291
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• 2013

본 논문은 금속 산화물 반도체의 산화막 두께, 채널 폭과 길이에 따른 실리콘 산화막의 신뢰성 특성을 연구하였다. 스트레스전류와 전이전류는 스트레스 전압에 의하여 발생된다. 스트레스 유기 누설전류는 스트레스 전압 인가 동안과 인가 후의 실리콘 산화막에 나타난다. 이때 저레벨 스트레스 전압에 의한 저레벨 누설전류는 저전압 인가 동안과 인가 후의 얇은 실리콘 산화막에서 발생한다. 저레벨 누설전류는 각각 스트레스 바이어스 조건에 따라 스트레스전류와 전이전류를 측정하였다. 스트레스 채널전류는 일정한 게이트 전압이 인가동안 측정하였고 전이 채널전류는 일정한 게이트 전압을 인가한 후에 측정하였다. 본 연구는 소자의 구동 동작 신뢰성을 위하여 저레벨 스트레스 바이어스 전압에 의한 스트레스 전류와 전이전류가 발생되어 이러한 저레벨 누설전류를 조사하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.50-52
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• 2006

본 논문은 고성능 다결정 실리콘(Poly-Si) 박막 트랜지스터 (Thin Film Transistor)에서 단일 수직 그레인 경계(Single Perpendlcular Grain Boundary)가 고온 캐리어 스트레스(Hot Carrier Stress) 및 정전류 안정성 평가에서 어떠한 효과를 보이는가에 대해서 살펴보았다. 고온 캐리어 스트레스 하에서($V_G=V_{TH}+1V,\;V_D$ =12V),그레이 경계가 없는 다결정 실리콘 TFT와 비교했을 때 그레인 경계를 가지고 있는 다결정 실리를 TFT는 전기 전도(Electric Conduction)에 작용하는 자유 캐리어(Free Carrier)의 개수가 적기 때문에 상대적으로 더욱 우수한 전기적 특성을 나타낸다. 먼저 1000초 동안 고온 캐리어 스트레스를 가해준 결과 단일 그레인 경계를 가진 다결정 실리콘에서의 트랜스 컨덕턴스(Transconductance)의 이동 정도는 5% 미만으로 확인되었다. 반면에 같은 스트레스 조건 하에서 그레인 경계가 존재하지 않는 다결정 실리콘의 경우에는 그 이동 정도가 약 25%에 달하는 것으로 측정되었다. 다음으로 정전류 스트레스(Constant Current Stress) 인가시, 수직형 그레인 경계가 채널 영역 내에 존재하지 않는 다결정 실리콘 TFT는 드레인 접합 부분의 전계 세기를 비교했을 때, 그레인 경계를 가지고 있는 다결정 실리콘 TFT보다 상대적으로 낮은 원 인 때문에 적게 열화되는(Degraded) 특성을 확인할 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제37권2호
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• pp.128-136
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• 2009

Curved glued laminated timber (glulam) is rapidly coming into the domestic modern timber frame buildings and predominant in building construction. The radial stress is frequently occurred in curved beams and is a critical design parameter in curved glulam. Three models, Wilson equation, Exact solution and Approximation equation were introduced to determine the radial stress of curved glulam under pure bending condition. It is obvious that radial stress distribution between small radius and large radius was different due to slight change of neutral plane location to center line. If the beam design with extremely small radius, it should be considered to determine the exact location of maximum radial stress. The current standard KSF 3021 was reviewed and would be considered some adjustment determining the optimum radius in curved glulam. Current design principle is that the stress factor is given by the curvature term only in constant depth of the beam, but like tapered or small radius of beams, the stress factor by Wilson equation was underestimated. So current design formula should be considered to improvement for characterizing the radial stress factor under pure bending condition.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.777-777
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• 2005