• 한국소음진동공학회논문집
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• 제22권8호
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• pp.736-741
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• 2012

Squeak noise is studied by using the pin-on-disk system with aluminum pin and steel disk. Noise induced by friction is measured with respect to the normal loads and sliding speeds. The negative slope of friction-velocity curve is seen when the squeak noise occurs. It is found that the normal load influences on the sound level of squeak noise. From the hammering test, the major frequency of the squeak noise is shown to correspond to one of system modes, which implies that squeak phenomenon arises from the unstable system modes. The result of FE analysis shows that the major squeak mode is the bending mode of the pin.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1617-1621
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• 2005

In this study, as a basic research to improve braking efficiency of a ventilated disk brake, we carried out a thermal stress analysis. From analysis result, we knew that a maximum mechanical stress by braking pressure and friction force is applicable to 5 percent of yield strength and has no effect on a fatigue life's decrease for brake disk material. While, a maximum thermal stress by frictonal heat is applicable to 43 percent of yield strength and locates on a friction surface. So, we have found that a thermal stress is the primary factor of crack initiation on a friction surface of disk brake

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.215-216
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• 2005

Nowadays, mobility as well as basic performances has been the important performance index of hard disk drive, It makes a system unstable to satisfy mobility, huge storage capacity and high transfer rate. Shock and vibration analysis has been important because hard disk drive could be exposed by external shock and vibration. The probability of this situation has been increasing. In this research, each component and the whole system of 2.5in HDD are made to a finite element model. Results of finite element analysis are compared with the results of experimental modal analysis. Shock analysis is executed for 2.5in hard disk drive.

• Advances in nano research
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• 제15권2호
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• pp.91-104
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• 2023

Development of thin carbon nanotubes (CNTs) nanoliquid film over the rough surface of a horizontal rotating disk is investigated by considering symmetric roughness either along the azimuthal or radial directions. The disk surface is either heated or cooled axisymmetrically from below. The effects of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) are analyzed on the film thinning process with different types of base liquids. Closed form solutions for velocity and temperature field are obtained for small values of Reynolds number whereas the numerical solution is derived for moderate values of Reynolds number. It is found that fluid retention / depletion takes place when the roughness is symmetric along the azimuthal / radial directions. It is also seen that the film thinning rate enhances for MWCNTs compare to SWCNTs. Further it is found that two different heat transfer regions exits within the flow domain depending on the fact that heat is transferred from disk to liquid film and vice-versa.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.975-985
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• 2011

Cu-Matrix sintered brake pads and low alloyed heat resistance steel are most applied to basic brake system for high energy moving machine. In this research, we analyzed tribological characteristics for influence of air velocity between disk and pad. At low brake pressure with air flow, friction stability was decreased due to no formation of tribofilm at disk surface. But there are no significant change of friction coefficient at all test conditions. Wear rate of friction materials were decreased with increasing of air flow velocity. In result, air flow velocity influenced friction stability, wear rate of friction materials and disk but not friction coefficient.

• Tribology and Lubricants
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• 제29권2호
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• pp.98-104
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• 2013

Cu-matrix-sintered brake pads and heat-resistant low-alloy steel are commonly applied to basic brake systems in high-energy moving machines. We analyzed how the tribological characteristics are influenced by the inertial mass. A high inertial mass decreased the friction coefficient by about 15% compared to a low inertial mass under all velocity conditions. The wear rates of the friction materials increased with the inertial mass. Thus, the inertial mass influences the friction coefficient and wear rate of the friction materials and disk but not the friction stability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.3-8
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• 1997

This parer was presented for the experimental results of torsional vibrations of the horizontal rotating shaft with three disks. The torsional vibrations meter used is a laser system for non-contact measurement of torsional angular vibration velocity and torsional angular vibration displacement. The distance between the disks war changed; the one that had 76mm of disk distance war called basic model, and another that had 106mm of disk distance wide model, and other that had 46mm of disk distance narrow model. In each model, outer diameter of disk was 40mm. And 45mm, or 50mm was also used to extend the effective range of frequencies. The angula vibration displacement and the angular vibration velocity in its torsional vibration were measured to obtain the stable and the unstable regions.

• 동력기계공학회지
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• 제13권1호
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• pp.33-38
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• 2009

In this study, the nose of cam in the automobile engine was modelled into circular disk to analyze the torsional vibration of the cam shaft. The distance between disks was fixed, but the diameter of disks was changed. The torsional vibration of the cam shaft was studied experimentally by the motion of the modelled disk with changing the disk diameter. And the sizes of the modelled disk were selected not to show the natural frequencies over all the experimental ranges. The torsional vibration meter used in this study has a laser system with non-contact measurement method, which can measure both torsional angular vibration velocity and torsional angular vibration displacement simultaneously. The Experimental analysis shows that the characteristics of the torsional vibration in the horizontal rotating shaft can be considerably affected by the arrangement of the modelled disks.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.958-961
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• 2002

The optical disk drive is a basic option on the PC now. So the lower price and higher read/write speed goods are now on market. These trends make many difficulties to produce more reliable drives, comparing when they are treated as high price stuff. In mechanical terms, the lower price and higher read/write speed drive make higher vibration and noise, lower stiffness, even severe fracture of cheap and low quality disk, problems. Due to the internal crash of P/U inside of the drive, the failure of drives, inferior drives, increase more and more by the careless transportation and the originated low stiffness parts. This report is the introduction of the FE simple model to decrease the internal P/U crash problems, and the results.

• 분석과학
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• 제11권5호
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• pp.321-331
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• 1998

기체크로마토그래피/질량분석법(GC/MS)을 이용하여 물시료 중에 미량으로 함유된 19종의 여러고리방향족탄화수소류에 대한 액체-액체 추출법, disk추출법 및 고체상 추출법을 이용한 시료 매트릭스로부터 분리, 추출하는 방법을 조사하였다. GC/MS의 오븐온도프로그램을 $80{\sim}310^{\circ}C$까지 단계적으로 변화시킨 결과 19종의 PAH류를 분리할 수 있었다. 액체-액체 추출법에 의한 물시료 중 PAH류의 회수율은 71.3~109.5% 범위로 나타났고, filtration에 의한 $C_{18}$ disk추출법의 회수율은 80.7~94.9% 범위로 높게 나타났다. 그러나 $C_{18}$ Sep-Pak을 사용한 고체상 추출법의 회수율은 51.8~77.9%범위이었다. 이상의 추출법에 대한 추출 회수율, 재현성 및 실험의 편리성 등 장단점을 비교한 결과, $C_{18}$ disk를 사용한 거르기법이 PAH류의 추출에 가장 적합한 방법임을 확인하였다. 각 추출법의 검출한계(S/N=5)는 액체-액체 추출법 및 고체상 추출법의 경우 0.25~6.25 ppb, disk추출법은 0.05~1.25 ppb 범위이었다.