• 제목/요약/키워드: Atomic Force Microscope

검색결과 688건 처리시간 0.029초

진동방식의 원자간력 현미경으로 표면형상 측정시 발행하는 혼돈현상의 적응제어 (Adaptive Control of the Atomic Force Microscope of Tapping Mode: Chaotic Behavior Analysis)

  • 강동헌;홍금식
    • 제어로봇시스템학회논문지
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    • 제6권1호
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    • pp.57-65
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    • 2000
  • In this paper, a model reference adaptive control for the atomic force microscope (AFM) of tapping mode is investigated. The dynamics between the AFM system and al sample is mathematically modeled as a second order spring-mass-damper system with oscillatory inputs. The attractive and repulsive forces between the tip of the AFM system and the sample are derived using the Lennard-Jones potential energy. By non-dimensionalizing the displacement of the tip and the input frequency, the chaotic behavior near a resonance frequency is better depicted through the non-dimensionalized equations. Four nonlinear analysis techniques, a phase portrait, sensitive dependence on initial conditions, a power spectral density function, and a Pomcare map are investigated. Because the equations of motion derived in this paper involve unknown parameter values such as the damping effect of the air and the interaction constants between materials, the standard model reference adaptive control is adopted. Two control objectives, the prevention of chaos and the tracking of reference signal, are pursued. Simulation results are included.

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직교 스캐너와 레이저 간섭계를 사용한 교정용 원자현미경 (Atomic Force Microscope for Standard Length Metrology)

  • 이동연;김동민;권대갑
    • 대한기계학회논문집A
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    • 제30권12호
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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.

원자스케일 마찰의 하중 및 강성 의존성 (Load and Stiffness Dependence of Atomistic Sliding Friction)

  • 성인하
    • Tribology and Lubricants
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    • 제23권1호
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    • pp.9-13
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    • 2007
  • Despite numerous researches on atomic-scale friction have been carried out for understanding the origin of friction, lots of questions about sliding friction still remain. It is known that friction at atomic-scale always shows unique phenomena called 'stick-slips' which reflect atomic lattice of a scanned surface. In this work, experimental study on the effects of system stiffnesses and load on the atomic-scale stick-slip friction of graphite was performed by using an Atomic Force Microscope and various cantilevers/tips. The objective of this research is to figure out the dependency of atomic-scale friction on the nanomechanical properties in sliding contact such as load, stiffness and contact materials systematically. From this work, the experimental observation of transitions in atomic-scale friction from smooth sliding to multiple stick-slips in air was first made, according to the lateral cantilever stiffness and applied normal load. The superlubricity of graphite could be verified from friction vs. load experiments. Based on the results, the relationship between the stickslip behaviors and contact stiffness was carefully discussed in this work. The results or this work indicate that the atomic-scale stick-slip behaviors can be controlled by adjusting the system stiffnesses and contact materials.

원자력현미경을 이용한 나노임프린트 재료의 접착력 측정 (Adhesion Force Measurements of Nano-Imprint Materials Using Atomic Force Microscope)

  • 윤형석;이몽룡;송기국
    • 폴리머
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    • 제38권3호
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    • pp.358-363
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    • 2014
  • 원자력현미경(AFM) tip을 표면 처리하여 임프린트용 acrylate 레진과의 접착력을 측정하였다. 표면 처리를 하지 않은 실리콘 tip에 비하여 $CH_4$ 플라즈마로 소수성 처리한 경우 접착력은 38% 감소한 반면 친수성의 $O_2$ 플라즈마로 처리한 경우에는 접착력이 1.6 배 증가하였다. 이러한 AFM 결과들은 정성적 실험 결과 밖에 얻을 수 없는 cross-cut 접착실험에 비하여 매우 구체적인 정량적 결과들을 제공하였다. 나노 크기의 임프린트 패턴을 전사하는 경우, 몰드와 레진 사이 접촉 면적이 커져서 시료 전체의 접착력이 커지기 때문에 패턴 크기가 작아지는 나노임프린트 공정에서는 몰드 표면 처리 문제가 더욱 중요하게 되는 것을 알 수 있었다.

공초점현미경과 원자현미경을 이용한 가공된 시료 표면의 형상측정 (Analysis of a processed sample surface using SCM and AFM)

  • 배한성;김경호;문성욱;남기중;권남익;김종배
    • 한국정밀공학회지
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    • 제23권4호
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    • pp.52-59
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    • 2006
  • Surface qualities of a micro-processed sample with a pulse laser have been investigated by making use of scanning confocal microscope(SCM) and atomic force microscope(AFM). Samples are bump electrodes and ITO glass of LCD module used in a mobile phone and a wafer surface scribed by UV laser. A image of $140{\times}120{\mu}m^2$ is obtained within 1 second by SCM because scan speed of a x-axis and y-axis are 1kHz and 1Hz, respectively. AFM is able to correctly measure the hight and width of ITO, and scribing depth and width of a wafer with a resolution less than 300nm. However, the scan speed is slow and it is difficult to distinguish a surface composed of different kinds of materials. Results show that SCM is preferable to obtain a image of a sample composed of different kinds of material than AFM because the intensity of a reflected light from the surface is different for each material.

다중주파수 AFM 원리 및 연구 동향 (Principle and Applications of Multifrequency Atomic Force Microscopy)

  • 이수일;김일광
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 춘계학술대회 논문집
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    • pp.88-89
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    • 2014
  • In dynamic force microscopy, the cantilever oscillates at a resonant frequency, and the tip deflection is measured at this frequency. The cantilever deflection is, however, highly nonlinear, and the surface properties can be embedded in the deflection at the frequencies other than the original resonant frequency of the cantilever. Multifrequency atomic force microscopy includes the excitation and detection of the deflection in two or more frequencies which are higher harmonics or eigenmodes. This can overcome the limitations of conventional atomic force microscope. We reviewed the multifrequency atomic force microscopy and its applications in many fields.

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원자력간 현미경을 이용한 TRIP강 저항 점용접부의 미세조직 분석에 관한 연구 (Analysis of Microstructure for Resistance Spot Welded TRIP Steels using Atomic Force Microscope)

  • 최철영;지창욱;남대근;장재호;김순국;박영도
    • Journal of Welding and Joining
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    • 제31권1호
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    • pp.43-50
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    • 2013
  • The spot welds of Transformation Induced Plasticity (TRIP) steels are prone to interfacial failure and narrow welding current range. Hard microstructures in weld metal and heat affected zone arenormally considered as one of the main reason to accelerate the interfacial failure mode. There fore, detailed observation of weld microstructure for TRIP steels should be made to ensure better weld quality. However, it is difficult to characterize the microstructure, which has similar color, size, and shape using the optical or electron microscopy. The atomic force microscope (AFM) can help to analyze microstructure by using different energy levels for different surface roughness. In this study, the microstructures of resistance spot welds for AHSS are analyzed by using AFM with measuring the differences in average surface roughness. It has been possible to identify the different phases and their topographic characteristics and to study their morphology using atomic force microscopy in resistance spot weld TRIP steels. The systematic topographic study for each region of weldments confirmed the presence of different microstructures with height of 350nm for martensite, 250nm for bainite, and 150nm for ferrite, respectively.

음향방출과 다구찌 방법을 이용한 나노머시닝 가공조건의 최적화 (Optimization of Nano-machining parameters using Acoustic Emission and Taguchi Method)

  • 손정무;이성환;최장은
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.50-55
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    • 2003
  • Atomic force microscope(AFM) techniques are increasingly used for tribological studies of engineering surfaces at scales ranging from atomic and molecular to microscale. AFM with suitable tips is being used for nanofabrication nanomachining purposes. In this paper, machining characteristics of silicon have been investigated by nano indentation and nano scratch. Mechanisms of material removal on the microscale are studied and the Taguchi method is introduced to acquire optimum parameters for nanomachining. This work shows effectiveness of the Taguchi method in nanomachining. Also, Acoustic Emission(AE) is introduced for the monitoring of nanomachining.

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음향방출과 다구찌 방법을 이용한 나노머시닝 가공조건의 최적화 (Optimization of Nano Machining Parameters Using Acoustic Emission and the Taguchi Method)

  • 이성환;손정무
    • 한국정밀공학회지
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    • 제21권3호
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    • pp.163-170
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    • 2004
  • Atomic force microscope (AFM) techniques are increasingly used fur tribological studies of engineering surfaces at scales ranging from atomic and molecular to micro-scale. Recently, AFM with suitable tips is being used for nano fabrication/nano machining purposes. In this paper, machining characteristics of silicon were investigated by nano indentation and nano scratch. Nano-scale material removal mechanisms are studied and the Taguchi method was introduced to acquire optimum parameters for nano machining. Also, Acoustic Emission (AR) is used for the monitoring of nano machining.