• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1182-1185
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• 2003

Recently, the research of the nano technology has been done on a lot of area over the world. Especially, the interest of them is much higher for semiconductor companies and other super accuracy processing area. In this thesis, we have approached the characteristic of the tensile and bonding of copper, frequently used to nano wires, by molecular dynamics simulation. And the simulation was done by EAM, Embedded Atom Method which has the most highest accuracy for metal. Then the feature of copper at atom space is understood through the simulation of nano wire.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.863-864
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• 2009

• Journal of the Korean Society for Precision Engineering
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• v.30 no.4
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• pp.409-413
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• 2013

A polypropylene film was ablated using a $CO_2$ laser, Ti-sapphire femtosecond laser, and UV nanosecond laser. For modified atmosphere packaging, polypropylene films were ablated by laser pulse with different pulse energies and measured on an optical microscope. Also, we observed the shelf life of a banana contained within packaging of a breathable zipper bag. As a result, we have demonstrated that the breathable film can efficiently extend the shelf life of respiring foods, particularly fresh fruits and vegetables. The development of breathable film laser microfabrication system will more useful for industrial applications.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.228-233
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• 2009

An ultra-precision stage is used in many industrial areas such as precision machine tools or semiconductor apparatus. These stages used to be driven by piezoelectric actuators in order to obtain ultra precision positioning resolution. Piezoelectric actuator can be moved fast in nanometer resolution. However, it has relatively large non-linear characteristics like hysteresis and creep curve. Although several kinds of control techniques have been developed, controller design method is still complicated. In this paper fuzzy control rules are developed intuitively. In order to verify the performance a series of experiments were conducted and the results were compared with those of the PID controller case.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.671-672
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• 2006

We have investigated the behavior of the ultrafast laser ablation of chromium films (200nm) on the silicon and pyrex-glass(corning 7740) substrate with respect to the laser fluence and the number of laser pulses. In addition, several experiments about ITO thin film were carried out with femto-second Ti:Sapphire laser (150fs). Finally, we introduce the ablation characteristic in accordance with materials of thin film and substrate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.527-528
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• 2006

In the proposed research plan, the effects of anisotropic and time-dependent mechanical properties on nanoindentation measurements of osteonic lamellae in a human cortical bone are investigated. The most popular method(Oliver-Pharr method) in nanoindentation data analysis is based on the assumption of elastic isotropy. Since cortical bone has exhibited anisotropy, it is necessary to consider the effects of anisotropy on nanoindentation measurement for cortical bone. By comparison with the contact area obtained from monitoring the contact profile in FEA simulations, the Oliver-Pharr method was found to underpredict or overpredict the contact area due to effects of anisotropy. The mount of error depended on the indentation orientation. The indentation modulus results and were also similar to moduli calculated from mathematical model. The Oliver-Pharr method has been shown to be useful for providing first order approximations in analysis of anisotropic mechanical properties of cortical bone, although the indentation modulus is influenced by anisotropy.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.71-78
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• 2005

The purpose of this study is to suggest a hyperfine maskless writing technique by using the nanoindentation and HF wet etching technique. Indents were made on the surface of Pyrex7740 glass by the hyperfine indentation process with a Berkovich diamond indenter, and they were etched in $50\;wr\%$ HF solution. After etching process, convex structure was obtained due to the deformation-induced hillock phenomena. In this study, effects of indentation process parameters (etching time, normal load, loading .ate, hold-time at the maximum load) on the morphologies of the indented surfaces after isotopic etching were investigated from an angle of deformation energies. Finally, sample characters were written to show the possibility of the application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.463-464
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• 2006

This paper present experimental results by non-contact mode Atomic Force Microscopy using high aspect ratio tips (HAR-T). We fabricated the carbon nanotube tip based on dielectrophoresis and the carbon nano probe by focused ion beam after dielectrophoretic assembling. In this paper, we measure AAO sample and trench structure to estimate HAR-T's performance and compared with conventional Si tip. We confirmed that results of HAR-T's performance in non contact mode was very superior than conventional tip.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.503-504
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• 2006

Determination of elastic properties of nano-scale materials using nano-indentation tests is well established, but that of plastic properties is not yet clear. This paper presents a method to extract plastic properties from nano-indentation test, together with results from detailed elastic-plastic FE analysis. It shows that the plastic properties determined from this method are not unique, in the sense that a number of different plastic properties can give the same load-displacement response from nano-indentation test. possible ways to overcome such problems are discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.135-135
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• 2004

21세기 정보화시대에 미디어의 발전은 고저장밀도를 요구하는 정보저장 장치의 개발을 필요로 하게 되었고, 현재 정보저장 장치의 주류를 이루는 magnetic recording 방식에 의한 HDD는 향후 5년 이내에 초자성한계 (super paramagnetic limit)라는 물리적 현상에 직면하여 더 이상 발전이 어려울 깃이다 따라서 이러한 한계를 극복하기 위한 여러 기술 증 Scanning Probe Microscope (SPM)을 이용한 차세대 탐침형 정보저장 기술은 미세한 끝단 반경을 가지는 탐침과 표면의 상호작용을 이용하여 정보를 기록/재생하는 기술로써 수십 nm 크기의 bit를 형성하여 Tbit/in$^2$ 이상의 높은 저장밀도를 가질 수 있으므로 현재 가장 상용화될 가능성이 높다.(중략)