• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.24-26
• /
• 2012

데이터 저장장치로 널리 사용되고 있는 플래시 메모리의 블록들은 소거 횟수가 제한되어 있어서 특정 블록에 소거 동작이 집중되지 않도록 마모 균등화 기능을 제공해야 한다. 저장 장치의 데이터들은 주기적으로 갱신이 자주 되는 hot데이터와 갱신이 거의 일어나지 않는 cold 데이터로 구성된다. 이런 두 가지 타입의 데이터로 인해 발생하는 소거 횟수에 대한 편차를 줄이기 위하여 정적 마모 균등화 기법을 사용하는데 데이터 이동에 따른 추가적인 소거 동작이 발생하게 된다. 본 논문에서는 데이터 이동 결정을 위한 임계값을 제어하여 플래시 메모리 내의 전체 블록들의 평균 소거 횟수가 크지 않을 때는 마모 균등화 작업을 자주 발생하지 않게 하고, 평균 소거 횟수가 소거 허용 한계치에 점차 근접하면 설정된 임계값으로 동작하도록 하여 정적 마모 평준화에 의해 추가되는 소거 횟수를 효율적으로 감소시키는 방법을 제안한다.

• Proceedings of the KWS Conference
• /
• 1994.10a
• /
• pp.180-182
• /
• 1994

• Journal of the Korean Society for Railway
• /
• v.15 no.3
• /
• pp.224-230
• /
• 2012

The wearing slider of the rail motor car's pantograph is considerable changed by the type and the material properties. Especially, precipitation and arc influences are main factors decided to life time of wearing slider and contact wire. This study is wearing phenomenon analysis of Cu-type wearing slider with high electric conductivity and resistance arc through experiment by running train. Author observed that wearing phenomenon of Cu-type wearing slider with normal and abnormal wearing characteristics and comparatively analysis precipitation, mileage and weight influences of exchanged Cutype and Fe-type wearing sliders. In this paper result showed that necessity for the application which is the Fe-type of wearing slider had superior wear resisting capacity etc., through tribology approach.

• Proceedings of the Korean Institute of Landscape Architecture Conference
• /
• 2002.03a
• /
• pp.50-53
• /
• 2002

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.3
• /
• pp.293-299
• /
• 2022

Recently, various stakeholder are interested in microplastic to cause pollution of the marine's ecosystem and effort to conduct study of product's life cycle to reduce pollution of marine's ecosystem. The micorplastic refer to materials of the nano- to micro- sized units and it can be classified into primary and secondary. The primary microplastic mean the manufactured for use in the specific field such as the microbead of the cosmetic or cleanser. also, secondary mean the unintentionally generated during use of the product such as the textile crumb by the doing the laundry. Tire and Road Wear Particles(TRWPs) are also defined as secondary microplastic. Typically, TRWPs are created by friction between the tread compound's rubber of the tire and the surface of the road du ring the driving cars. Most of the generated TRWPs exist on the roadside and some of them were carried to marine by the rainwater. In this study, we perform the quantitative analysis of the TRWPs existed in fine dust at the roadside. So, we collected the dust from the roadside in Chungcheongnam-do's C site with a movement of 1,300 cars per the hour. The collected samples were separated according to size and density. And shape analysis was performed using the Scanning Electron Microscope(SEM). We were possible to discover a lot of TRWPs at the fine dust of the 100 ± 20 ㎛. And we analysis it u sing the Thermo Gravimetric Analysis(TGA) and Gas Chromatography/Mass Spectrometer(GC/MS) for the quantitative components from the tire. As a result, it was confirmed that TRWPs generated from the roadside fine dust were included the 0.21 %, and the tire and road components in the generated TRWPs consisted of the 3:7 ratio.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.2
• /
• pp.1-7
• /
• 2005

In order to determine the wear Properties of PECVD ceramic coatings, wear process was evaluated using the coated pin of Falex Tribosystem. Coating materials deposited wear the TiC, TiN and Ti(CN). An experimental process was established to determine the tribological characteristics of friction and wear behavior under the variation of applied load, temperature and sliding distance by the Falex test machine. The experimental results indicate that TiN coating compared with TiC coating on e materials have e excellent friction and wear characteristics. However TiC coating compared i친 TiN coatings have a low friction coefficient with steel and good thermal stability, and Ti(CN) has the excellent anti-wear properly as well as the superiority of extreme pressure property. Compound coating compared wi simple coatings show improved tribological characteristics.

• Tribology and Lubricants
• /
• v.9 no.1
• /
• pp.9-15
• /
• 1993

Tribology는 미끄럼 혹은 구름베어링, 피스톤링, 기어, 공구, 그밖의 상대적 움직임하에 있는 부품의 설계 및 제조와 관련된 학문이다. 또한 tribology는 서로 접촉하는 재료의 적절한 사용, 윤활유와의 상호작용 이해 및 적절한 선택을 통해 마모와 마찰의 감소 혹은 최적의 마찰(브레이크, 벨트 등의 경우)을 위해 연구되는 분야이다. 부품의 내마모성을 향상시키고 적절한 마찰계수를 얻기 위해서는 기계 설계, 윤활유 선택 및 개발, 재료의 선택 및 개발 등 여러 분야의 기여가 모두 필요하다. 지금까지는 전통적으로 사용되어 오던 재료, 특히 금속재료를 중심으로 하여 기계 및 윤활제 개발 등에 치중하여 왔다. 그러나 산업이 발전되고 복잡화됨에 따라 극한 분위기 즉 고온, 고진공하에서의 장시간 사용과 고효율 등을 요구하여 최근의 tribology 분야에 사용되는 부품들의 신소재로의 대체를 요구하고 있다. 한 예로 지금의 엔진보다 더 고온에서 작동되는 고효율의 경량의 첨단 열엔진의 개발을 들 수 있다. 이러한 열 엔진의 사용목적을 달성하기 위해서는 기존의 금속재료로는 고온에서 작동괴기에는 너무 약하고 무겁기 때문에 구조용 세라믹스가 고려되고 있는 것이다. 신소재 분야중 세라믹스는 고기능성 부품과 이미 산업화된 분야의 부품의 대체 재료로 주목을 받고 있다.

• Journal of Welding and Joining
• /
• v.16 no.1
• /
• pp.114-124
• /
• 1998

The effect of matrix phase (austenite, pearlite, martensite) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iorn hardfacing weld deposites has been investigated. In order to examine matrix phase, a series of alloys with different matrix phase by changing the ratio of Cr/C system by heat treatment were employed. The alloys were deposited twice on a mild steel plate using self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test(RWAT). Even though formation of pearlite phase in the matrix showed higher hardness than that of austenite, there was no observable difference in wear resistance between the pearlite and austenite phase for the same amount of chromium-carbide in the matrix. On the other hand, the formation of martensitic phase,, from heat treated austenitic alloys (high content of Cr), enhanced wear resistance due to its fine secondary precipitates.

• Journal of Welding and Joining
• /
• v.16 no.1
• /
• pp.125-133
• /
• 1998

The effect of volume fraction of Cr carbide phase (Cr CVF) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iron hardfacing weld deposits has been investigated. In order to examine Cr CVF, a series of alloys with varying Cr CVF by changing chromium and carbon contents and the ratio of Cr/C were employed. The alloys were deposited once or twice on a mild steel plate using the self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test (RWAT). It was shown that hardness and abrasion resistance increased with increasing Cr CVF within the whole test range (Cr CVF : 0.23-0.64). Both primary Cr carbide and eutectic Cr carbide were particularly effective in resisting wear due to their high hardness.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.190-191
• /
• 2012

철계 소결 부품은 성형의 용이성, 저렴한 가격, 특유의 기공성 입계조직으로 기능성 표면처리에 적합한 소재이다. 본 연구에서는 고온 부식 및 극심한 마모환경에 노출되는 발전소 터빈과 같은 부품의 표면처리에 주로 쓰이는 Pack-chromizing 법을 적용한 철계 소결부품의 내마모 특성을 알아보고자 한다. AFM 분석결과, Pack-chromizing 에 의해 Cr이 확산된 표층의 형상이 Peak-and-Valley 형태의 치밀한 dimple 구조로 변화된 것을 알 수 있었다. 또한, XRD 및 XPS 분석을 통해 chromium carbide 및 $Cr_2O_3$와 같은 고경도의 화합물 층이 형성됨을 알 수 있었다. 따라서, 이러한 dimple 구조를 띈 고경도의 화합물 층이 표면의 마찰계수를 저하시키는 주요 원인임을 본 연구에서 논하고자 한다.