• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.108.6-108
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• 2002

It is greatly important to understand the mechanics of AFM-based nanorobotic manipulation for efficient and reliable handling of nanoparticles. Robust motion control of an AFM-based nanorobotic manipulation is much challenging due to uncertain mechanics in tip-sample interaction dominated by surface and intermolecular force and limitations in force and visual sensing capability to observe environment. This paper investigates a nanomechanic modeling which enables simulation for AFM-based nanorobotic manipulation , and its application to motion planning of an AFM-based nanorobot. Based on the modeling of intermolecular and adhesion force in AFM-based nanomanipulation, the behaviors of an AFM ca...

• 한국식품과학회지
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• 제41권2호
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• pp.215-219
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• 2009

$AFB_1$의 대사산물 중 하나인 $AFM_1$을 사람과 돼지의 뇨에서 cdELISA를 통해 분석함으로써 간접적으로 $AFB_1$의 위해성 평가를 수행하고자 하였다. 항 $AFM_1$ 항체와 ${AFB_1}-HRP$를 이용한 cdELISA에서 $AFM_1$의 검출한계는 10 pg/mL로 나타났다. 사람의 요에 $AFM_1$을 3-100 pg/mL 농도가 되게 첨가한 후 cdELISA로 분석하였을 때 그 회수율은 117-167%(평균 139${\pm}$19.1)의 범위로 나타났다. 사람의 뇨 중 $AFM_1$의 오염량을 cdELISA로 분석한 결과 전체 172개의 시료 중 165개의 시료에서 평균 2.74${\pm}$1.89 pg/mL 농도로 검출되었다. 뇨 중 $AFM_1$의 일일배출량은 평균 3.97 ng/day으로 나타났고, $AFB_1$의 섭취량은 체내전환율 5%로 가정하였을 때, 79.4 ng/day로 추정되었다. 따라서 사람의 일일섭취추정량 (PDI)은 1.28 ng/kg bw/day로 나타났으며 돼지의 PDI는 9.2 ng/kg bw/day로 나타났다. 한편 $AFB_1$ 섭취의 위해성 평가에서 사람의 PDI는, 일일섭취감내량(TDI, 0.15 ng/kg bw/day)보다 8.5배나 높은 값을 보였지만 외국의 연구결과와 비교하였을 때 대체로 비슷하게 나타났다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.264-267
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• 2003

Pitch measurements of 150 nm pitch one-dimensional grating standards were carried out using an contact mode atomic force microscopy(C-AFM) with a high resolution three-axis laser interferometer. It was called as 'Nano-metrological AFM' In Nano-metrological AFM, Three laser interferometers were aligned well to the end of AFM tip. Laser sources of the three-axis laser interferometer in the nano-metrological AFM were calibrated with an I$_2$-stablilzed He-Ne laser at a wavelength of 633 nm. So, the Abbe error was minimized and the result of the pitch measurement using the nano-metrological AFM has a traceability to the length standard directly. The uncertainty in the pitch measurement was estimated in accordance with the Guide to the Expression of Uncertainty in Measurement(GUM). The Primary source of uncertainty in the pitch-measurements was derived from repeatability of pitch-measurement, and its value was approx 0.186 nm. Expanded uncertainty(k=2) of less than 5.23 nm was obtained. It is suggested that the metrological AFM is a useful tool for the nano-metrological standard calibration.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.8-13
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• 1996

A relatively new non-traditional finishing process called Abrasive Flow Machining(AFM) is being used to deburr, polish and radius workpiece or produce compressive residual stresses by flowing an abrasive-laden viscoelastic compound across the surface to be machined. This paper presents the effects of AFM on surfaces of tool steel produced by EDM and W-EDM. Using AFM, white layer produced by EDM is erased almost equally and the amount of metal removal is significantly affected the initally machined surface condition of workpiece. The dimension of workiece is enlarged and its surface roughness is improved as AFM time is increased. The optimal AFM time can be established from the experimental results. It is considered that the grinding method lide AFM is useful to grind complex or slim geometry of workpiece even. Scanning Electron Microscopy(SEM) was used to study the surface characteristics of the workpiece before and after AFM.

• 한국정밀공학회지
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• 제15권3호
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• pp.99-106
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• 1998

Recently, scientists introduced a new type of microscope capable of investigating nonconducting surfaces in an atomic scale, which is called AFM (Atomic Force Microscope). It was an innovative attempt to overcome the limitation of STM (Scanning Tunnelling Microscope) which has been able to obtain the image of conducting surfaces. Surfaces of samples are imaged with atomic resolution. The AFM is an imaging tool or a profiler with unprecedented 3-D resolution for various surface types. The AFM technology, however, leaves a lot of room for improvement due to its delicate and fragile probing mechanism. One of the room for improvements is gap control between probe tip and sample surface. Distance between probe tip and sample surface must be kept in below one Angtrom in order to measure the sample surface in Angstrom resolution. In this paper, AFM system modeling, experimental system identification and control scheme based on system identification are performed and finally sample surface is measured by home-built AFM with such a control scheme.

• 한국식품위생안전성학회지
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• 제16권3호
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• pp.200-205
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• 2001

시중 유통중인 유 및 유제품의 AFM$_1$의 오염수준을 파악하기 위해 분석한 결과 우유의 경우는 원유(0.083 ppb)에 비해 시유의 AFM$_1$농도(0.047 ppb)가 낮게 나타났으나 이는 살균의 효과라기보다 집유 과정에서의 희석 때문인 것으로 보이며, 탈지분유의 경우 AFM$_1$의 농도가 0.24 ppd로 높게 나타났으나 섭취시 희석되므로 우유와 큰 차이는 없을 것으로 생각되었다. 아이스크림제품의 경우 AFM$_1$오염농도는 0.020 pub로 나타났다. 이상의 결과는 미국 FDA의 허용기준치인 0.5 ppb보다 월등히 낮은 수치로 나타난 것이다. 국내 시판 우유 중 AFM$_1$오염수준을 평가하기 위해 본 연구의 결과와 기존의 국내 연구 결과를 토대로 Monte-Carlo 시뮬레이션을 시행하였다. 불확실성과 다양성을 고려하기 위해 fitting 절차를 거쳤으며, 시판 우유 중 AFM$_1$의 발생정도(prevalence)를 추정하기 위해 beta distribution을, 우유에서의 AFM$_1$오염농도(concentration)를 추정하기 위해 triangular distribution을 적용한 결과, 국내 시판 우유에서 AFM$_1$의 발생 가능한 오염수준(contamination level)은 최소(5% percentile) 0.0214, 평균(50% percentile) 0.0946 및 최대(95% percentile) 0.1888 ppb로 나타났다. 전체적으로 미국의 AFM$_1$허용기준치인 0.5 ppb보다는 상당히 낮은 수준이지만 시판우유의 80.4%근 유럽의 기준인 0.05ppb보다 높은 수준으로 예측되어 유럽의 허용기준치를 초과하는 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.875-881
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• 2004

Fundamental results obtained from an atomic force microscope (AFM) chemically-induced direct nano-lithography process are presented, which is regarded as a simple method for fabrication nm-scale devices such as superconducting flux flow transistors (SFFTs) and single electron tunneling transistors (SETs). Si cantilevers with Pt coating and with 30 nm thick TiO coating were used as conducting AFM tips in this study. We observed the surfaces of superconducting strip lines modified by AFM anodization' process. First, superconducting strip lines with scan size 2 ${\mu}{\textrm}{m}$${\times}$2 ${\mu}{\textrm}{m}$ have been anodized by AFM technology. The surface roughness was increased with the number of AFM scanning, The roughness variation was higher in case of the AFM tip with a positive voltage than with a negative voltage in respect of the strip surface. Second, we have patterned nm-scale oxide lines on ${YBa}-2{Cu}_3{O}_{7-x}$ superconducting microstrip surfaces by AFM conductive cantilever with a negative bias voltage. The ${YBa}-2{Cu}_3{O}_{7-x}$ oxide lines could be patterned by anodization technique. This research showed that the critical characteristics of superconducting thin films were be controlled by AFM anodization process technique. The AFM technique was expected to be used as a promising anodization technique for fabrication of an SFFT with nano-channel.

• Environmental Analysis Health and Toxicology
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• 제23권1호
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• pp.47-51
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• 2008

The toxicity of environmental pollutants was measured between a image of the surface topography in HeLa cells using atomic force microscopy for the possibility of toxic effect measurement and environmental monitoring. A image of the surface topography by AFM were estimated as toxic endpoints. The surface topography by AFM was observed a change of the cell surface in the environmental pollutants, but the standard of the measurement requires for the dose-effect degree. The overall results indicate that the possibility of measurement using AFM were confirmed a dose-effect degree related toxic effects, but it requres correlation between more various biomarker and AFM's measurements if the possibility of the toxic effect measurement was established.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.375-378
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• 2002

In this paper, the frequency response separation scheme is proposed for high scanning speed and simple structure of non-contact type of AFM. A self-sensing cantilever is attached on the actuator for detect the atomic force between tip and the media surface. VCM or PZT are used for actuator. This paper presents the method to simplify the actuator structure and the performance of each actuator for non-contact type AFM. Based on the frequency response separation scheme, the only one actuator plays roles 1311owing low frequency surface and modulating self-sensing cantilever tip in contrast with convention non-contact type AFM. 10 ${\mu}{\textrm}{m}$ standard grid sample imaged to verify proposed scheme. This result shows the possibility simplifying the actuator structure and reducing cost of non-contact type AFM.

• 대한기계학회논문집A
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• 제31권6호
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• pp.659-664
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• 2007

$Moire\'{e}$ interferometry is a useful technique to assess the reliability of electronic package because $Moire\'{e}$ interferometry can measure the whole-field and real-time deformations. The shear strain of a small crack site is important to the reliability assessment of electronic package. The optical limitation of $Moire\'{e}$ interferometry makes ambiguous the shear strain of a small area. An atomic force microscope (AFM) is used to measure the profile of a micro site. High resolution of AFM can apply to the $Moire\'{e}$ technique. AFM $Moire\'{e}$ technique is useful to measure the shear strain of a small area. In this research, the method to accurately measure the deformation of a small area by using AFM $Moire\'{e}$ is proposed. A phase-shifting method is applied to improve the resolution of AFM $Moire\'{e}$.