• 제목, 요약, 키워드: Wear

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유기복합필러를 함유하는 차과용 컴퍼짓 레진의 파괴와 마멸거동 (Fracture and Wear Behavior of Dental Composite Resins Containing Prepolymerized Particle Fillers)

  • 김영빈;김교한;김석삼;임정일
    • 대한기계학회논문집A
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    • v.24 no.2
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    • pp.464-471
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    • 2000
  • The fracture and wear behavior of dental composite resins containing prepolymerized particle fillers were investigated. Composite resins such as Metafil, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to evaluate the effect of prepolymerized particle fillers in fracture and wear characteristics. Ball on flat wear tester was used for the wear test at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistances of Silux Plus and Palfique Estelite were better than those of Metafil and Heliomolar at the same experimental condition. It was found that the main wear mechanism was abrasive wear containing of plastic deformation of dental material.

Time-Aware Wear Leveling by Combining Garbage Collector and Static Wear Leveler for NAND Flash Memory System

  • Hwang, Sang-Ho;Kwak, Jong Wook
    • 한국컴퓨터정보학회논문지
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    • v.22 no.3
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    • pp.1-8
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    • 2017
  • In this paper, we propose a new hybrid wear leveling technique for NAND Flash memory, called Time-Aware Wear Leveling (TAWL). Our proposal prolongs the lifetime of NAND Flash memory by using dynamic wear leveling technique which considers the wear level of hot blocks as well as static wear leveling technique which considers the wear level of the whole blocks. TAWL also reduces the overhead of garbage collection by separating hot data and cold data using update frequency rate. We showed that TAWL enhanced the lifetime of NAND flash memory up to 220% compared with previous wear leveling techniques and our technique also reduced the number of copy operations of garbage collections by separating hot and cold data up to 45%.

생산수량에 따른 Ti-N 코팅 펀치의 마멸해석 (Wear Analysis of the Ti-N Coated Punch in Piercing According to the Volume of Production)

  • 황상홍;고대철;김병민
    • 한국정밀공학회지
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    • v.17 no.3
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    • pp.149-157
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    • 2000
  • Tool wear in the shearing process such as blanking, piercing and trimming is very important, because it has great effects on the dimensional accuracy, working efficiency and economy. Most of tools in the shearing process have the coated layer at surface fur good wear and corrosion resistance. When the surface of tool is teated, the wear Phenomena of coated surface layer and inner layer may be different. This paper describes a computer modelling technique by the finite element method in order to investigate the wear mechanism and to predict the wear profile of Ti-N coated tool in piercing process according to the volume of Production. Wear coefficients of the coated layer and inner layer are obtained through Pin-on-Disk wear test, respectively. To verify the effectiveness of the suggested technique, the technique is applied to wear analysis in piercing recess of piston pin and simulation results are compared with experimental ones.

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유기복합필러를 포함하는 치과용 콤포짓트 레진의 마모거동(제1보) (Wear Behaviours of Dental Composite Resins Containing Prepolymerized Particle Fillers (1st Report))

  • 임정일;김교한;김석삼
    • Tribology and Lubricants
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    • v.15 no.2
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    • pp.212-217
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    • 1999
  • The wear characteristics and wear mechanisms of dental composite resins were investigated. Composite resins such as Metafil, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to evaluate the effect of Prepolymerized Particle Fillers in friction and wear characteristics. Ball on flat wear tester was used for the wear test at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistances of Silux Plus and Palfique Estelite were better than that of Metafil and Heliomolar at the same experimental condition. It was found that The main wear mechanism is plastic flow and abrasive wear by failure of filler's bond to the matrix.

B.390 알루미늄 합금의 마모특성에 미치는 초정Si 입자크기와 잔류응력의 영향 (Effect of Primary Si size and Residual Stress on the Wear Properties of B.390 Al Alloys)

  • 김헌주;김성재
    • 열처리공학회지
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    • v.19 no.1
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    • pp.20-29
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    • 2006
  • Wear behaviour of B.390 aluminum alloy with different particle sizes of primary Si against a SM45C counterface was studied as a function of wear load and sliding velocity, using pin-on-disk apparatus under dry condition. The wear rate of specimen with fine primary Si particles showed increased wear resistance at high wear load, on the other side wear resistance of coarse primary Si particle size was improved at low wear load. As the compressive residual stress in the matrix increased remarkably by liquid nitrogen(LN) treatment, wear resistance of the LN treated specimen was more excellent than that of T6 treated specimen.

X선회절에 의한 철강재료의 미Rm럼 마모형태 해석에 관한 연구(고경도강에의 적용) (Analysis of Sliding Wear Mode on Hardened Steel by X-ray Diffraction Technique)

  • 이한영
    • Tribology and Lubricants
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    • v.20 no.1
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    • pp.7-13
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    • 2004
  • High strength steels are widely used as tribo-materials in the field. Previous study revealed that for mild steel, the states of strain on the worn surface measured by X-ray diffraction has a good relationship with the state of wear. The objective of this study is to identify the relationship between the state of strain on the worn surface and the state of wear in high strength steels. Sliding wear tests were carried out using several hardened steels. X-ray diffraction tests were conducted to analyze the state of strain on the worn surface during wear. The experimental results indicated that the state of strain on worn surface in the hardened steel shows the same tendency as in the mild steel. It is clear that change of half value width on the worn surface as a function of sliding speeds is broadly similar in shape to wear characteristics curve and its magnitude has a good relationship with the wear rate at two different wear modes in the hardened steel.

철강재료의 구름마찰시에 발생하는 마모형태에 관한 연구 (Discussion on Wear Ope of Steel in Rolling Friction)

  • 이한영
    • Tribology and Lubricants
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    • v.16 no.1
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    • pp.9-14
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    • 2000
  • It has been cleared in previous author's paper that the fatigue life before the pitting on the rolling contact surface with lubricant are influenced by the wear amount. In this study, the wear type has been clarified when wear amount is extremely large such as the case without lubricant. The test of rolling contact fatigue has been conducted under two different of herzian pressures and three different of slide ratios without lubricant. In addition, residual stress and half-value breadth using X-ray diffraction on worn surface have been measured as well as the wear amount. The results show that the pitting type wear by rolling contact fatigue has not been occurred when the wear amount is considerably large. Thus this type of wear has been deduced by the fatigue wear depending on delamination theory.

표면거칠기의 변화에 따른 a-C 박막의 나노마멸 거동 (Nano Wear Behavior of a-C Films with Variation of Surface Roughness)

  • 채영훈;장영준;나종주;김석삼
    • Tribology and Lubricants
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    • v.20 no.3
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    • pp.125-131
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    • 2004
  • Nano-wear behavior of amorphous carbon films was studied by Atomic Force Microscopy. The a-C films are deposited on Si(100) substrate by DC magnetron sputtering method. The influences of different surface roughness on the nano-wear are investigated. Nano-wear tests were carried out using a very sharp diamond coated tip. Its spring constant was 1.6 N/m and radius of curvature was 110 nm. Normal force used in the wear tests ranged 0 to 400 nN. It was found that surface depression occurred during scratching because of plastic deformation and abrasive wear (cutting St ploughing). Wear depth increased linearly with normal force. Changing the surface roughness variables according to the bias pulse control, the less surface roughness decreased the wear depth. The thickness did not affect the wear resistance.

플라스틱성형용 KP-4M강의 마멸특성 및 이의 기구에 관한 연구 (A Study on the Wear Characteristics and the Mechanism of KP-4M Steel for Plastic Molding)

  • 박흥식;전태옥;김동호
    • Tribology and Lubricants
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    • v.12 no.1
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    • pp.22-28
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    • 1996
  • This study was undertaken to investigate the dry wear characteristics and mechanism of KP-4M steel for plastic molding against SKD 61 hardened by heat treatment. The wear test was carried out under different conditions such as sliding speed, contact pressure, sliding distance, with frictional tester of pin on disc type. The wear loss on variation of sliding speed was little in lower speed range below 0.5 m/sec and in higher speed range above 1.5 m/sec,'but wear loss was high in intermediate speed range. The critical sliding speed, which showed the maximum value of specific wear rate, became lower with increased contact pressure. Increasing the contact pressure, the critical sliding distance Lcr which the wear mechanism changes from severe wear to mild wear was increased due to the decrease of oxidation reaction velocity. Through this study we suggested a model of generation and elimination process of wear debris of KP-4M steel for plastic molding.

탄소와 질소 함량에 따른 탄질소 복합첨가강의 내마멸 특성 변화 (Wear-characteristics variation of Fe-C-N alloy with changing content of carbon and nitrogen)

  • 박준기;이슬기;김성준;김용석
    • 한국소성가공학회:학술대회논문집
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    • pp.385-388
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    • 2009
  • Dry-sliding-wear behavior of Fe-18Cr-l0Mn steel with various carbon and nitrogen contents was characterized, and the effect of carbon and nitrogen contents on the wear was investigated. Dry sliding wear tests of the steel were carried out at room temperature against an AISI 52100 bearing steel ball using a pin-on-disk wear tester. Applied wear loads were varied from 10 N to 100 N, and the sliding distance was fixed as 720 m. Worn surfaces and the wear debris of the steel were examined using an SEM to find out the wear mechanism. It was found that the Fe-18Cr-10Mn with both carbon and nitrogen exhibited superior wear resistance to the steel with only nitrogen. The wear resistance of the Fe-18Cr-10Mn-xC-yN alloy increased with the increase of the carbon content. The excellent wear resistance of the Fe-18Cr-10Mn-xC-yN alloy was explained by the increased strain-hardening capability with the interstitial atoms.

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