• Applied Science and Convergence Technology
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• v.23 no.2
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• pp.97-102
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• 2014

A vacuum chamber for a commercial atomic force microscope (AFM) is designed and fabricated. Only minimal modifications were made to an existing microscope in an effort to work in a vacuum environment, while most of the available AFM functionalities were kept intact. The optical alignment needed for proper AFM operations including a SLD (superluminescent diode) and a photodiode can be made externally without breaking the vacuum. A vacuum level of $5{\times}10^{-3}$ torr was achieved with a mechanical pump. An enhancement of the quality factor was observed along with a shift in the resonance frequency of a non-contact-mode cantilever in a vacuum. Topographical data of a calibration sample were also obtained in air and in a low vacuum using the non-contact mode and the results were compared.

• KSTLE International Journal
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• v.7 no.1
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• pp.10-13
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• 2006

In this work, imaging and study of elastic property of the living cell was performed. The motivation of this work was to seek the possibility of exploiting Young's modulus as a disease indicator using Atomic Force Microscope (AFM) and also to gain fundamental understanding of cell mechanics for applications in medical nanorobots of the future. L-929 fibroblast adherent cell was used as the sample. Imaging condition in cell culturing media environment was done in very low speed ($20{\mu}m/ s$) compared to that in the ambient environment. For measuring the Young's modulus of the living cell, AFM indentation method was used. From the force-distance curve obtained from the indentation experiment the Young's modulus could be derived using the Hertz model. The Young's modulus of living L-929 fibroblast cell was $1.29{\pm}0.2$ kPa.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.167-174
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• 1998

In this work the surface damage of head and disk of a hard disk drive was analysed using an Atomic Force Microscope. The initial damage of the disk occurred by generation of extremely small wear particles. Also it was shown that wear particles tend to pile up near the front side of the slider. The surface damage mechanism of drag test and contact-start-stop test was found to be quite similar.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.22-30
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• 2005

This paper proposes a measurement method for the surface shape of micro-parts by using an atomic force microscope(AFM). To this end, two techniques are presented: First, the measurement range is expanded by using an image matching method based on correlation coefficients. To account for the inaccuracy of the coarse stage implemented in AFM, the image matching technique is applied to two neighboring images intentionally overlapped with each other. Second, a method to measure the shape of relatively large specimen is proposed that utilizes the inherent trigger mechanism due to the atomic force. The proposed methods are proved effective through a series of experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.161-164
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• 2000

Currently, Atomic Force Microscope(AFM) has been widely used to measure the surface topography of a sample by detecting interaction force between atoms on the sample and extremely sharp probe tip. The vertical resolution of AFM is mainly determined by external vibration noise. The resolution of AFM shows different values for the different environment, thus it is necessary to determine relationship between the criteria and the resolution of AFM regardless of environment. In this paper, we discuss the allowable level of floor vibration for AFM equipment at given resolution. The vibration criteria can be used as reference data to design mechanical structure and to analyze the structural dynamics of AFM equipment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1611-1617
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• 2006

A compact and two-dimensional atomic force microscope (AFM) using an orthogonal sample scanner, a calibrated homodyne laser interferometer and a commercial AFM head was developed for use in the nano-metrology field. The x and y position of the sample with respect to the tip are acquired by using the laser interferometer in the open-loop state, when each z data point of the AFM head is taken. The sample scanner which has a motion amplifying mechanism was designed to move a sample up to $100{\times}100{\mu}m^2$ in orthogonal way, which means less crosstalk between axes. Moreover, the rotational errors between axes are measured to ensure the accuracy of the calibrated AFM within the full scanning range. The conventional homodyne laser interferometer was used to measure the x and y displacements of the sample and compensated via an X-ray interferometer to reduce the nonlinearity of the optical interferometer. The repeatability of the calibrated AFM was measured to sub-nm within a few hundred nm scanning range.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.413-418
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• 2005

This paper proposes a measurement method for the surface of micro-parts by using AFM(Atomic Force Microscope). To this end, two techniques are presented to extend the capacity of AFM. First, the measurement range is extended by using an image matching method based on correlation coefficients. To account for the inaccuracy of the coarse stage implemented in AFM's, the image matching technique is applied to two neighboring images intentionally overlapped with each other. Second, a method to measure the shape of relatively large specimen is presented by using the inherent trigger mechanism due to the atomic force. The proposed method is proved effective through a series of experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.955-962
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• 2000

Scanning Probe Microscope (SPM) such as Scanning Tunneling Microscope (STM) and Atomic Force Microscope (AFM) was shown to be the powerful tool for nano-scale characterization of a fracture surface . AFM was used to study cross sectional profiles and dimensions of fatigue striations in 2017-T351 aluminum alloy. Their widths (SW) and heights (SH) were measured from the cross sectional profiles of three-dimension AFM images. The following results that will be helpful to understand the fatigue crack growth mechanism were obtained. (1) Coincidence of the crack growth rate with the striation width was found down to the growth rate of 10-5 mm/cycle. (2) The relation of SH=0.085(SW)1.2 was obtained. (3) The ratio of the striation height to its width SH/SW did not depend on the stress intensity factor range K and the stress ratio R. (4) Not only the SW but also the SH changed linearly with the crack tip opening displacement (CTOD) when plotted in log-log scale. From these results, the applicability of the AFM to nano-fractography is discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.560-562
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• 2009

In this paper, we proposed a simple method of decreasing the off current generated by degradation for improve the electrical characteristics such as mobility and on/off current ratio by making the line patterns on the pentacene surface between the electrodes using atomic force microscope (AFM) lithography.

• Tribology and Lubricants
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• v.21 no.5
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• pp.221-226
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• 2005

A new calibration method for exact measurement of friction force in atomic force microscope (AFM) is presented. A new conversion factor involves a contact factor affected by tip, cantilever and contact stiffness. Especially the effect of contact stiffness on the conversion factor between lateral force and lateral signal is considered. Conventional conversion factor and a new modified conversion factor were experimentally compared. Results showed that a new calibration method could minimize the effect of normal load on friction force and improve the conventional method. A new method could be applied to the specimens with different physical properties.