• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.744-751
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• 2000

To achieve lower flying height for high areal recording density, the laser zone texturing of the disk needs to be designed to reduce glide height. One problem of the laser bump design is that the regular laser bump pattern often produces glide resonance phenomenon, which leads to failure of the glide height test. However, it was found in this study that glide resonance is an intrinsic problem of the glide head used and resonance phenomenon depends on the type of the head slider, that is, the natural frequency of the slider body. Therefore, higher glide height or glide failure caused by glide resonance does not lead to head/media interface problem in the real drive operating conditions in which the data head is used. Pseudo-random bump pattern greatly reduces the glide resonance. Smaller bump pitch will also help to reduce the glide resonance. However, as bump spacing becomes smaller, glide height will be increased due to increased air pressure developed around the bumps. Lowering bump height is the most effect way to reduce glide avalanche.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.277-278
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• 2002

Magnetron and Ion beam sputtering were used to texture the air-bearing surface of magnetic recording sliders. Flying height measurements and Laser-Doppler interferometry were used to compare the 'flyability' of textured and untextured sliders. Lubricant redistribution on the disk surface caused by slider/disk interactions was investigated using scanning ellipsometry (Surface Reflectance Analyzer (SRA)). The results show that slider surface texture causes only small changes in the flying height of sliders but reduces slider in-plane and out-of-plane vibrations. Textured sliders were found to cause less lubricant depletion on the disk surface than untextured sliders.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.255-260
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• 2000

Laser zone texture technology is widely used to enhance the tribological performance of high areal density media. This work investigates the transient process of melting and microscale surface deformation upon pulsed laser heating of Ni-P hard disk substrates by PLIC(Piecewise Linear Interface Calculation) method. The present results are compared with both the experimental and the Donor-Acceptor method results. It is found that the results from PLIC method are better than those of Donor-Acceptor method and they are in good agreements with the experimental results.

• KSTLE International Journal
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• 제1권1호
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• pp.12-20
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• 2000

Nano-wear and friction of carbon overcoated laser-textured and mechanically-textured computer hard disk were characterised after contact start/stop (CSS) wear test. Various analytical and mechanical testing techniques were employed to study the changes in topography, roughness, chemical elements, mechanical properties and friction characteristics of the coating arising from the contact start/stop wear test These techniques include: the atomic force microscopy (AFM), the continuous nano-indentation test, the nano-scratch test, the time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and the auger electron spectroscopy (AES). It was shown that the surface roughness of the laser-textured (LT) bump and mechanically textured (MT) Bone was reduced approximately am and 7nm, respectively, after the CSS wear test. The elastic modulus and hardness values increased after the CSS test, indicating straining hardening of the top coating layer, A critical load was also identified fer adhesion failure between the magnetic layer and the Ni-P layer, The TOF-SIMS analysis also revealed some reduction in the intensity of C and $C_2$$F_59$, confirming the wear of lubricant elements on the coating surface.

• 한국응용과학기술학회지
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• 제19권3호
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• pp.245-249
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• 2002

A (disk-like liquid crystal (DLC) monomer/liquid crystals(LCs)/chiral dopant/dichroic dye) composite was irradiated with ultraviolet (UV) light. The (DLC network/LCs/chiral dopant/dichroic dye) was formed in the homeotropically oriented smectic A(SA) phase by the surface orientation treatment and the electric field. A focal-conic texture exhibiting strong light scattering appeared in the heat-induced chiral nematic phase(N${\ast}$) of the composite upon heating. Thermo-recording in the composite system has been realized by using a He-Ne laser. The laser irradiation was induced the phase transitions from SA phase to chiral nematic(N${\ast}$) phase in the composite system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1589-1595
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• 2000

레이저 텍스쳐와 미케니칼 텍스쳐 컴퓨터 하드디스크의 마찰과 마코 매카니즘이 Contact Start/Stop test 실행후의 특성들에 대해 연구되었다. 다양한 분석적이고 기계적인 테스트 기술들이 이용되었다. 형상, 조도, 화학적 조성, 기계적 성질, CSS 로부터 기인된 코팅의 마찰특성들에 대해 그 변화들을 조사하였다. 즉, AFM(Atomic Force Microscopy), Nano-Indentation, Nano-Scratch, TOF-SIMS(Time of Flight Secondary Ion Mass Spectroscopy), AES(Auger Electronic Spectroscopy)등이 이 연구에 적용되었다. 레이저 텍스쳐 범프의 표면조도와 미케니칼 텍스쳐 지역의 표면조도는 각각 대략적으로 4nm 와 7nm 감소되었다. 탄성계수와 경도값은 CSS test후에 증가하였고 가장 바깥쪽의 코팅층의 변형강화가 생겨났다. 자성층과 Ni-P 층 사이에 점착성의 문제가 확인되었다. TOF-SIMS 분석은 C 와 $C_2F_5$의 세기에 있어서 감소를 드러냈고 이것은 코팅 표면에 윤활제 요소의 마모를 확실시 할수 있는 결과로 나타났다.

• 대한치과교정학회지
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• 제31권6호
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• pp.567-578
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• 2001

본 연구는 metal stripper, diamond bur, cross-cut carbide bur을 이용한 기계적 삭제방법과 산을 이용한 화학적 삭제방법 등의 서로 다른 방법으로 삭제된 치아에서 삭제방법에 따른 법랑질 표면조도의 차이를 비교하고, 삭제된 법랑질 표면에 국소적 불소도포와 교정용 전색제를 적용시 치아우식 감수성에 미치는 영향을 알아보기 위해 교정적인 목적으로 발치된 100개의 소구치를 대상으로 주사전자현미경과 레이저 형광법을 이용하여 연구한 바 다음과 같은 결과를 얻었다. 1. 치간삭제방법에 관계없이 인접면 삭제 후 법랑질 표면에 형성된 열구는 세심한 연마과정을 통해서도 제거되지 않았다. 2. 기계적인 치간삭제 방법 중에 가장 활택한 법랑질 표면조도를 보이는 군은 crosscut tungsten carbide bur로 초기삭제 후 sof-$lex^{(r)}$ disk로 연마한 군이었다. 3. 기계적 방법이나 기계적과 화학적 방법을 동반하여 치간 삭제한 모든 군의 치아우식 감수성은 대조군보다 높았다. 그러나 치간삭제 방법에 따른 치아우식 감수성의 차이는 보이지 않았다(p<0.001). 4. APF-gel 이나 sealant을 도포한 군은 치간삭제 후 다른 처치를 하지 않은 군에 비해 치아우식 감수성이 낮았다(p<0.001). 5. APF-gel을 도포한 군이 sealant을 도포한 군보다 치아우식 감수성이 낮았다(P<0.05). 결론적으로, 치간삭제 후 활택한 법랑질 표면을 얻고자 하는 노력에도 불구하고 치간삭제를 실시한 치아는 그 삭제 방법에 관계없이 정상치아에 비해 치아우식 감수성이 높았다. 따라서 치간삭제 후 주기적인 불소의 사용이 치아우식을 예방하는 최선의 방법이라고 생각된다.