• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.122-127
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• 2006

This paper reports on the development of carbon nanotube tip modified with focused ion beam(FIB). We used an electric field which causes dielectrophoresis, to align and deposit CNTs on a metal-coated canning Probe Microscope (SPM) tip. Using the CNT attached SPM tip, we have obtained an enhanced resolution and wear property compared to that from the bare silicon tip through the scanning of the surface of the bio materials. The carbon nanotube tip was aligned toward the source of the ion beam allowing their orientation to be changed at precise angles. By this technique, metal coated carbon nanotube tips that are several micrometer in length are prepared for SPM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.461-462
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• 2006

This paper reports on the development of a scanning probe microscopy(SPM) tip with caborn nanotubes. We used an electric field which causes dielectrophoresis(DEP), to align and deposit CNTs on a metal-coated SPM tip. Using the CNT attached SPM tip, we have obtained an enhanced resolution and wear property compared to that from the bare silicon tip through the scanning of the surface of the bio materials. The carbon nanotube tip align toward the source of the ion beam allowing their orientation to be changed at precise angles. By this technique, metal coated carbon nanotube tips that are several micrometer in length are prepared for scanning probe microscopy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1503-1508
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• 2005

Scanning Thermal Microscope (STU) has been known for its superior resolution for local temperature and thermal property measurement. However, commercially available STU probe which is the key component of SThM does not provide resolution enough to explore nanoscale thermal phenomena. Here, we developed a SThM probe fabrication process that can achieve spatial resolution around 50 m. The batch-fabricated probe has a thermocouple junction located at the end of the tip. The size of the thermocouple junction is around 200 m and the distance of the junction from the very end of the tip is 150 m. The probe is currently being used for nanoscale thermal probing of nano-material and nano device.

• Journal of the Korean institute of surface engineering
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• v.44 no.1
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• pp.26-31
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• 2011

Numerical modeling is used to investigate the perturbation of a single Langmuir probe (0.2 mm diameter shielded with 6 mm insulator) inserted along the center axis of a cylindrical inductively coupled plasma chamber filled with Ar at 10 mTorr and driven by 13 MHz. The probe was driven by a sine wave. When the probe tip is close to a substrate by 24.5 mm, the probe characteristics was unperturbed. At 10 mm above the substrate, the time averaged electric potential distribution around the tip was severly distorted making a normal probe analysis impossible.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.50-54
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• 2005

We report a simple, low cost, and reliable method for assembling a multi-walled nanotube (MWNT) to the end of a metal coated scanning probe microscopy (SPM) tip. By dropping the MWNT solution and applying an electric field between an SPM tip and an electrode, MWNTs which were dispersed into a dielectric solution were directly assembled onto the apex of the SPM tip due to the attraction by the dielectrophoretic force. The effective measurement of a MWNT -attached SPM tip was demonstrated by direct comparison with AFM images of a standard sample with a bare AFM tip.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.199-200
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• 2007

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.353-361
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• 2002

The tip leakage flow passing through the clearance between rotor blade tip and casing shroud has been known to occupy an important portion of the rotor overall loss. In this study, flow characteristics in axial flow rotors with different tip clearances is investigated by experimental and numerical methods. The experimental study was carried out to measure static pressure and velocity profiles at the real rotating test rig. The axial flow rotors used for the experiments have ten blades and three different rotor diameter. The tip clearance heights are 1mm, 3mm, and 4.5mm. Measurements were done using spherical type five-hole probe by non-nulling method. The numerical study was carried out to calculate pressure distributions and velocity vectors at the same condition as the experiments in the flow fields of axial flow rotors using Phoenics code.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.152-152
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• 2008

Micro probe with Ni-Co tip was designed. Unit processes for fabricating the micro probe were developed. We are investigated the micro probe tip using by Ni-Co alloy. One-step and three-step needle was fabricated by plating process, CMP, and photolithography process. The plating thickness was varied by current density and time. Futher data will be extract by different process conditions.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.84-88
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• 2006

The effects of tip voltage, deflection setpoint, and tip velocity on height of $SiO_2$ line drawn by local anodization on Si wafer using scanning probe microscope were investigated. No local anodization was detected at smaller than -3 V of tip voltage. The line height increased at rate of 0.47 nm/V when the tip voltage is stronger than -3 V at $1{\mu}m/s$ tip velocity. From deflection setpoint, mechanical force between tip and substrate could be calculated and the threshold farce was $12\sim18nN$. The height of anodized $SiO_2$ lines is independent of the magnitude of force above the threshold force. The line height decreased as increasing the tip velocity and limited to 0.7 nm at -5 V tip voltage.

• The KSFM Journal of Fluid Machinery
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• v.12 no.2
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• pp.39-45
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• 2009

Leakage flow through turbine blade tip gap causes strong leakage vortex near the blade suction side and induces large aerodynamic losses. In this study, the conventional plane tip and various squealer tip blades were tested in a linear cascade in order to measure the effect of the tip shape on the total pressure loss. Three tip gap clearances of 0.6%, 1.3%, and 2.0% of blade span were tested. Flow measurement was conducted at one chord downstream from the trailing edge with a five-hole probe. Results showed that the leakage vortex was stronger than passage vortex and the mass averaged overall total pressure loss through the cascade was the lowest for suction side blade tip case. For all tested cases, the area averaged overall total pressure loss was increased as the tip clearance increased.