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基于精确探针模型的AFM图像重构研究 总被引:2,自引:1,他引:2
原子力显微镜技术已在纳米成像中得到了普遍应用.但实验表明,AFM图像在水平方向分辨率较低,其中探针针尖形貌是影响扫描图像分辨率的关键因素之一.为了提高AFM扫描图像的分辨率,改善成像质量,一种可行的方法是通过建立探针模型后,重构扫描图像.在已有的探针建模方法中,普遍采用盲建模算法.针对目前盲建模算法中降噪阈值难以优化问题,提出了一种降噪阈值最优估计新方法.该方法可以使盲建模算法更准确地建立扫描方向上的探针形貌轮廓,进而完成3D探针模型.通过应用AFM探针扫描多空铝和标准栅格实验,介绍了探针针尖形貌精确建模的方法.然后使用数学形态学的腐蚀运算对标准栅格的AFM成像进行了重构,验证了上述方法的有效性.实验结果证明,重构后的图像中降低了探针针尖形貌的失真影响,可以显著改善扫描探针显微镜成像的水平分辨率. 相似文献
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微纳米操作、加工、检测和控制在各个领域获得广泛的研究和应用,在微纳米层次上进行原位、定位的操作、检测、加工是经常遇到的问题。扫描探针显微镜技术(Scanningprobemicroscope,SPM)提供强有力的工具,人们利用其不同类型的针尖与相应样品表面产生的化学或物理作用达到目的。但扫描探针显微镜针尖同时用于检测、加工和成像,会因为针尖磨损、状态的改变,影响检测信息的准确性、可靠性,直接影响结果的判定。本文提出一种在微操作加工过程的定位检测技术,即操作过程工具和探针承担不同任务,工具负责加工操作,探针用于检测并定位于操作加工位置,进行了实验并分析讨论定位过程相关问题。 相似文献
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原子力显微镜(Atomic force microscopes,AFM)接触模式下的测量结果因受样本表面倾角和针尖一样本表面间摩擦力的影响而存在较大的测量误差.为避免针尖-表面间的摩擦力对AFM测量试样表面形貌的影响,并能够准确测量表面倾角,提出了一种新的AFM工作模式--消除倾角和摩擦力影响模式.在这种工作模式中,扫描方向垂直悬臂的长轴方向,通过测量悬臂的竖向和横向偏转而得到针尖所受的竖向和横向力,并计算得到针尖-试样表面间的van der Waals力及试样表面局部倾角,然后结合针尖项点和扫描器的位置及针尖-试样表面间距可以得到试样表面形貌的测量结果.在上述工作模式下,针尖-试样表面间的摩擦力是可控的,能够避免针尖或试样的损伤.仿真结果证明了这种方法的可行性. 相似文献
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基于散射式近场探测原理,设计并搭建了散射式太赫兹扫描近场光学显微系统(THz s-SNOM),实现了纳米量级空间分辨率的太赫兹近场显微成像测量。该系统以输出频率范围为0.1~0.3THz的太赫兹倍频模块为发射源,通过纳米探针的针尖产生纳米光源与样品相互作用,并将样品表面的倏逝波转化为可在远场测量的辐射波。通过探针逐点扫描样品表面,同时获得了样品表面的形貌图和太赫兹近场显微图。该系统的显微分辨率取决于探针针尖的曲率半径,而与太赫兹波的波长无关。使用该系统测量了金薄膜/硅衬底样品和石墨烯样品的近场显微图,结果表明,近场显微的空间分辨率优于60nm,波长与空间分辨率之比高达λ/26000。 相似文献
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Eum Hark-Jin Kang Young-Seok Kang Shin-Hyoung 《Journal of Mechanical Science and Technology》2004,18(6):979-989
Numerical simulations have been performed to investigate tip clearance effect on through-flow and performance of a centrifugal
compressor which has the same configuration of impeller with six different tip clearances. Secondary flow and loss distribution
have been surveyed to understand the flow mechanism due to the tip clearance. Tip leakage flow strongly interacts with mainstream
flow and considerably changes the secondary flow and the loss distribution inside the impeller passage. A method has been
described to quantitatively estimate the tip clearance effect on the performance drop and the efficiency drop. The tip clearance
has caused specific work reduction and additional entropy generation. The former, which is called inviscid loss, is independent
of any internal loss and the latter, which is called viscous loss, is dependent on every loss in the flow passage. Two components
equally affected the performance drop as the tip clearances were small, while the efficiency drop was influenced by the viscous
component alone. The additional entropy generation was modeled with all the kinetic energy of the tip leakage flow. Therefore,
the present paper can provide how to quantitatively estimate the tip clearance effect on the performance and efficiency. 相似文献
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单极芒刺静电净化装置芒刺和极板间距对电流密度的影响 总被引:1,自引:0,他引:1
为了通过优化单极芒刺净化装置的结构参数,解决芒刺静电油烟净化装置中对微小油烟颗粒收集效率低的问题,采用数值模拟的方法研究了单极芒刺板-板式油烟静电净化装置中芒刺尖端与收极板间距对电流密度的影响。采用合适的静电场控制方程,提出了芒刺板-板极配方式的边界条件,选择有限体积法对电场进行了数值模拟计算,并将计算结果与实验值进行了对比。分析研究结果表明所建立的数值模拟方法可靠。在此基础上分别分析了芒刺尖端与收极板的间距和工作电压对收集板上电流密度的大小及分布的影响。分析结果表明,当间距取40 mm~75 mm时,在工作电压范围内,电流密度分布均匀,且电流密度强,说明该间距范围是最佳值。 相似文献
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This paper reports on the spatial distribution and polarization behaviour of the optical near-field at the aperture of a Si micromachined probe. A sub-100 nm aperture at the apex of a SiO2 tip on a Si cantilever was successfully fabricated by selective etching of the SiO2 tip in a buffered-HF solution using a thin Cr film as a mask. The aperture, 10–100 nm in size, can be reproducibly fabricated by optimizing the etching time. The optical throughput of several apertures was measured. For a 100 nm aperture, a throughput of 1% was approved. The probe shows a very high optical throughput owing to the geometrical structure of the tip. The spatial distribution of the near-field light is measured and simulated using a finite difference-time domain method. The polarization behaviour of apertures with different shapes was analysed using a photon counting camera system. 相似文献
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F. H'dhili R. Bachelot A. Rumyantseva G. Lerondel & P. Royer 《Journal of microscopy》2003,209(3):214-222
We show experimentally that local optical field enhancement can occur at the end of an apertureless SNOM tip illuminated by an external light source. Our approach consists in the use of a photosensitive polymer, placed in the tip near‐field, to record intensity distribution in the vicinity of the tip end. The excited nanometre‐size light source permits us to produce nano‐patterns on the polymer surface which are then characterized by atomic force microscopy. Experimental images show the influence, on the field enhancement, of three important experimental parameters: the polarization state of the incident light, the geometry of the external illumination and the radius of curvature of the tip apex. These results are shown to be in good agreement with two‐dimensional numerical calculations based on the finite‐difference time‐domain method. We show preliminary nanometre‐size patterns created by this nano‐source excited at a metallic tip extremity and discuss the potential of this approach for near‐field optical lithography. 相似文献
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Fourier and hyperbolic models of heat transfer on a fin that is subjected to a periodic boundary condition are solved analytically.
The differential equation in Fourier and non-Fourier models is solved by the Laplace transform method. The temperature distribution
on the fin is obtained using the residual theorem in a complex plan for the inverse Laplace transform method. The thermal
shock is generated at the base of the fin, which moves toward the tip of the fin and is reflected from the tip. The current
study of various parameters on the thermal shock location shows that relaxation time has a great influence on the temperature
distribution on the fin. An unsteady boundary condition in the base fin caused the shock, which is generated continuously
from the base and has interacted with the other reflected thermal shocks. Results of the current study show that the hyperbolic
heat conduction equation can violate the second thermodynamic law under some unsteady boundary conditions. 相似文献
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由于受到驱动器PZT(Pb Zr Ti O3)非线性、系统温漂与其他不确定因素的影响,原子力显微镜(AFM)探针在任务空间的位置存在不确定性。这严重影响了AFM探针观测与操作的效率,如何减小探针位置的不确定性,实现AFM探针的精确定位成为亟待解决的问题。针对此问题,提出用概率分布的方式描述探针位置的不确定性,通过建立探针运动模型,结合基于局部扫描的观测模型,采用Kalman滤波对探针位置进行最优估算。针对算法的实现,设计了模型参数标定方案。通过仿真和实验的结果验证了算法的有效性与可行性,实现了探针在任务空间中的精确定位,提高了纳米操作效率。 相似文献
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