• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.11
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• pp.990-995
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• 2005

This paper reports the fabrication and characterization of $5\;\times\;5$ thermal cantilever array for nano-scaled memory device application. The $5\;\times\;5$ thermal cantilever array with integrated tip heater has been fabricated with MEMS technology on SOI wafer using 7 photo masking steps. All single-level cantilevers have a diode in order to eliminate any electrical cross-talk between adjacent tips. Electrical measurements of fabricated thermal cantilever away show its own thermal heating mechanism. Thermal heating is demonstrated by the reflow of coated photoresist on the cantilever array surface.

• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.79-87
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• 2003

An in-situ four-electrode contact resistivity probe system was designed, and field-tested in submarine sediments. Seismic survey was also performed to support and compare the results of electric survey. The probe was designed to be driven to selected depths below the seafloor using a Vibracore system. The four insulated electrodes were, spaced equidistant across the wedge, were extended beyond the probe tip to minimize effects of sediment disturbance by the wedge insertion. In-situ measurements of resistivity were recorded on board by precision electronic equipment consisting of signal generators and processors, and by temperature- monitoring systems. Overall limits of uncertainty at respective depths below the seafloor are up to ±10% of the measured values. Best estimates of conductivity are considered to be ±3 percent of the reported values. Resistivity measurements were made at six sites in carbonate sediments to a maximum depth of penetration of about 5 m. Average values of conductivity range between 0.88 and 1.21 mho/m. The results show the seabed is composed of alternating layers of relatively high-conductivity material (0.8 to 1.4 mho/m) in thicknesses of more or less one meter and layers about 30 cm thick having relatively low conductivities (0.4 to 0.8 mho/m).

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1529-1530
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• 2006

현재 한빛 플라즈마에서 운영되고 있는 전자기 진단장치는 정전탐침, 자장탐침 및 반자성루프 둥이 있다. 정전탐침은 고정식, 이동식, 고속주사방식 세 종류의 진단장치가 개발되어 실험에 이용되어 왔는데 비교적 쉽게 많은 종류의 probe와 다양한 probe tip을 구성할 수 있기 때문에 한빛 장치에서 axial 및 azimuthal 방향으로 전자 온도/밀도 및 그들의 분포를 측정하고 있다. 단일탐침에서 사용되던 RF 보상기술을 삼중탐침에서도 적용시켜 RF 보상 삼중탐침을 개발하였다. 기존의 삼중탐침의 경우에는 DC에 대해서는 높은 임피던스로 외부에 부유되어 있지만 RF의 경우에는 외부와 부유되지 않고 낮음 임피던스로 연결되어있는 경우가 많았다. 하지만 RF보상 삼중탐침의 경우에는 RF의 경우에도 충분히 큰 임피던스로 부유되어 있다. 따라서 보다 왜곡되지 않은 측정을 할 수 있다. RF보상 삼중탐침을 이용하여 한빛 Mirror 플라즈마에서 axial 방향으로 Plasma 변수들의 변화를 관찰하면서 기존의 탐침에서 볼 수 얼던 여러 특성을 관찰할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.273-276
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• 2006

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

• Transactions on Electrical and Electronic Materials
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• v.9 no.4
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• pp.169-172
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• 2008

We attempted to fabricate carbon nanotube field effect transistor (CNT-FET) using single walled carbon nanotube(SWNT) on the heavily doped Si substrate used as a bottom gate, source and drain electrode were fabricated bye-beam lithography on the 500 nm thick $SiO_2$ gate dielectric layer. We investigated electrical and physical properties of this CNT-FET using Scanning Probe Microscope(SPM) and conventional method based on tungsten probe tip technique. The gate length of CNT-FET was 600 nm and the diameter of identified SWNT was about 4 nm. We could observed gating effect and typical p-MOS property from the obtained $V_G-I_{DS}$ curve. The threshold voltage of CNT-FET is about -4.6V and transconductance is 47 nS. In the physical aspect, we could identified SWNT with phase mode of SPM which detecting phase shift by force gradient between cantilever tip and sample surface.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.327-327
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• 2011

A nonthermal bioplasma source was developed for application to human liquid fluids by making use of nano-size tungsten tips. Characteristics of the plasma source are investigated. Here we have used the AC voltage system. The bioplasma source generated by a tungsten tip with quartz tube and ground electrode is a low-temperature plasma without making any noticeable damage to cells at a low power operation. The breakdown voltage and current signals are measured by high voltage probe (Tektronix P6015A) and current probe (P6021). Variation of breakdown temperature near the tip electrode is larger than that in the neighborhood of ground electrode. Bubble formation during discharge has been recorded and investigated by using the high speed camera. The existence and behavior of hydroxyl and superoxide radicals are detected and measured by spectrometers. The electrical and optical properties of breakdown characteristics are also investigated.

• Journal of the Korean Chemical Society
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• v.61 no.1
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• pp.12-15
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• 2017

We presented a mapping the work function of the vanadium pentoxide ($V_2O_5$) nanonet structures by scanning Kelvin probe microscopy (SKPM). In this measurement, the $V_2O_5$ nanonet was self-assembled via dropping the solution of $V_2O_5$ nanowires (NWs) onto the $SiO_2$ substrate and drying the solvent, resulting in the networks of $V_2O_5$ NWs. We found that the SKPM signal as a surface potential of $V_2O_5$ nanonet is attributed to the contact potential difference (CPD) between the work functions of the metal tip and the $V_2O_5$ nanonet. We generated the histograms of the CPD signals obtained from the SKPM mapping of the $V_2O_5$ nanonet as well as the highly ordered pyrolytic graphite (HOPG) which is used as a reference for the calibration of the SKPM tip. By using the histogram peaks of the CPD signals, we successfully estimated the work function of ~5.1 eV for the $V_2O_5$ nanonet structures. This work provides a possibility of a nanometer-scale imaging of the work function of the various nanostructures and helps to understand the electrical characteristics of the future electronic devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.661-669
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• 1999

A probe card is one of the most important pan of test systems as testing IC(integrated circuit) chips. This work was related to bump-type silicon vertical probe card which enabled simultaneous tests for multiple semiconductor chips. The probe consists of silicon cantilever with bump tip. In order to obtain optimum size of the cantilever, the dimensions were determined by FEM(finite element method) analysis. The probe was fabricated by RIE(reactive ion etching), isotropic etching, and bulk-micromachining using SDB(silicon direct bonding) wafer. The optimum height of the bump of the probe detemimed by FEM simulation was 30um. The optimum thickness, width, and length of the cantilever were 20 $\mum$, 100 $\mum$,and 400 $\mum$,respectively. Contact resistance of the fabricated probe card measured at contact resistance testing was less than $2\Omega$. It was also confirmed that its life time was more than 20,000 contacts because there was no change of contact resistance after 20,000 contacts.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.51-60
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• 2011

Electrical resistivity is applied for understanding details about layers and obtaining basic properties of soils to various measurement devices. The objective of this study is development of TRP(Temperature-compensated Resistivity Probe), analysis about effects of temperature changes during cone penetration test, and observation of characteristics of cone penetration. In order to observation of temperature changes according to a diameter difference of resistivity cone probe, the cone which has wedge type cone tip is made to two types, 2mm and 5mm. Temperature sensor is attached at 15mm below from cone tip because of an electrical interference with elecrical resistance probe. Delectrical connector is used to prevent electric disturbance between motor type penetrating machine and electrical resistivity cone probe. Application tests are carried out in acrylic cell whose diameter is 30cm with uniform Jumunjin sand according to densification caused by blows. The test results indicate that the temperature is increased uniformly during penetration and a tendency, characteristics of cone penetration, is discovered during altering state of soils. This study suggests that the temperature effects and characteristics of penetration should be considered in penetrating tests in order to conduct an accurate ground investigation using TRP(Temperature-compensated Resistivity Probe).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.149-150
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• 2006

We describe a novel method of scanning probe nanofabrication using a AFM(atomic force microscopy) tip with assistance of Femtosecond laser pulses to enhance fabrication capability. Illumination of the AFM tip with ultra-short light pulses induces a strong electric field between the tip and the metal surface, which allows removing metal atoms from the surface by means of field evaporation. Quantum simulation reveals that the field evaporation is triggered even en air when the induced electric field reaches the level of a few volts per angstrom, which is low enough to avoid unwanted thermal damages on most metal surfaces. For experimental validation, a Ti: sapphire Femtosecond pulse laser with 10 fs pulse duration at 800 nm center wavelength was used with a tip coated with gold to fabricate nanostructures on a thin film gold surface. Experimental results demonstrate that fine structures with critical dimensions less than ${\sim}10nm$ can be successfully made with precise control of the repetition rate of Femtosecond laser pulses.