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Tapping Mode AFM Imaging in Liquids with blueDrive Photothermal Excitation
摘要： Photothermal excitation represents a significant instrumentation advance for imaging with dynamic modes of the atomic force microscope (AFM). Using a power-modulated laser to directly drive the cantilever oscillation provides substantial benefits over conventional piezoelectric excitation. Here we discuss photothermal excitation and its implementation as blueDrive by Oxford Instruments Asylum Research. We explain its operating principles and discuss its use for a range of practical applications. The results show that blueDrive sets new standards for imaging in liquid, visualizing dynamic events, and mapping nanomechanical properties.
关键词： tapping mode,liquid imaging,photothermal excitation,atomic force microscopy,nanoscale surface characterization
更新于2025-09-23 15:21:01
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Surface Characterization of Nanoscale Co-Crystals Enabled through Tip Enhanced Raman Spectroscopy
摘要： Atomic Force Microscopy coupled with Tip Enhanced Raman Spectroscopy (AFM-TERS) was applied to obtain information about structure and surface composition of single nano co-crystals. For this purpose, a co-crystalline system consisting of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazatetracyclo-[5.5.0.03,11.05,9]-dodecane (CL-20) and 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane (HMX) in a molar ratio of 2:1 (CL-20/HMX) were chosen. CL-20/HMX nano-plates were prepared by Spray Flash Evaporation. To ensure co-crystallinity and nanostructure, powder X-Ray Diffraction and AFM investigations were performed. Results demonstrate that coherence lengths and particle dimensions are on a similar level though coherence lengths appear shorter than measured particle dimension. According to this fact, defects inside the nano co-crystals are minimized. The co-crystallinity was additionally proven by confocal Raman spectroscopy. Here, marker bands for pristine CL-20 and HMX were chosen which appear in the CL-20/HMX spectrum in an intensity ratio of ~ 2.5:1 (CL-20:HMX). Afterwards surface investigations of single CL-20/HMX nano-plates were performed by AFM-TERS. Due to the surface sensitivity of TERS, these experiments reveal that the ratio of the Raman intensities between CL-20 and HMX inverts at CL-20/HMX nano-plate surfaces. Therefore, it is concluded that nano co-crystal surfaces consist of molecular layers of HMX. A theoretical approximation of the normal coordinates of the investigated marker vibrations supports this conclusion since it can exclude the occurrence of the intensity ratio inversion because of the given orientation between CL-20/HMX nano-plates and the Raman scattering system. Based on this finding, an impact ignition mechanism is proposed.
关键词： surface characterization,CL-20/HMX,AFM-TERS,Raman spectroscopy,nano co-crystals
更新于2025-09-23 15:19:57
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Confidence Distance Matrix for outlier identification: A new method to improve the characterizations of surfaces measured by confocal microscopy
摘要： This paper proposes a statistical method for outlier identification for surface measurement data obtained by confocal microscopy. The implemented statistical method is Confidence Distance Matrix (CDM) which were widely used in statistics and many engineering areas, such as signal processing, sensor data fusion, information problems, etc. However, no investigations on identifying outliers in measured surface data using CDM have been found. This paper introduces and simplifies the mathematical model of CDM method. Algorithms for identifying random outliers using Monte Carlo method for uncertainty evaluation and for identifying outliers in a unique measured surface are developed and validated. For validation of the algorithms, a synthetic data SG_3-3 provided by National Institute of Standards and Technology and a data of artificial stochastic surface generated by our own algorithms are implemented. The difference of Sq of the data with outliers is 2.3342% and after deletion of outliers is 0.0037% with reference to the certified value. A type C1 spacing standard with dust dropped is measured and processed using CDM. The difference of Sa decreases from 29.65% to 3.52% after processing outliers with reference to the certified value Ra. An iron surface is measured and processed. Surface slopes and curvatures of the data in the two validations and two experiments are compared. All those parameters, the surface reconstructions, histogram of heights, and QQ plot of the measured surface data versus the data after deletion of outliers indicate our proposed method working well.
关键词： Confidence Distance matrix,outlier detection,areal surface characterization,threshold determination,Imaging Confocal Microscopy,Monte Carlo method
更新于2025-09-19 17:15:36
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Development of a Monitoring Strategy for Laser-Textured Metallic Surfaces Using a Diffractive Approach
摘要： The current status of research around the world concurs on the powerful influence of micro- and nano-textured surfaces in terms of surface functionalization. In order to characterize the manufactured topographical morphology with regard to the surface quality or homogeneity, major efforts are still required. In this work, an optical approach for the indirect evaluation of the quality and morphology of surface structures manufactured with Direct Laser Interference Patterning (DLIP) is presented. For testing the designed optical configuration, line-like surface patterns are fabricated at a 1064 nm wavelength on stainless steel with a repetitive distance of 4.9 μm, utilizing a two-beam DLIP configuration. Depending on the pulse to pulse overlap and hatch distance, different single and complex pattern geometries are produced, presenting non-homogenous and homogenous surface patterns. The developed optical system permitted the successfully classification of different pattern geometries, in particular, those showing single-scale morphology (high homogeneity). Additionally, the fabricated structures were measured using confocal microscopy method, and the obtained topographies were correlated with the recorded optical images.
关键词： homogeneity characterization,periodic structures,diffraction analysis,direct laser interference patterning,indirect surface characterization
更新于2025-09-16 10:30:52
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Production and Tribological Characterization of Tailored Laser-Induced Surface 3D Microtextures
摘要： The aim of the present study was firstly to determine the manufacturing feasibility of a specific surface 3D-microtexturing on steel through an ultra-short pulsed laser, and secondly to investigate the tribological properties under 2 different lubrication conditions: oil-lubricated and antifriction coated. The selected 3D-microtexture consisted of 2 different levels of quadratic micropillars having side dimensions of approximately 45 μm, heights of about 35 μm and periods of 80 μm. It was shown that the production of specific 3D-microtextures on steel substrates using an ultra-short pulsed laser was feasible, and that the reproducibility of the texture dimensions over the entire textured region was extremely good. Frictional investigations have shown that, in comparison to the benchmark (untextured samples), the 3D-microtextured samples do not induce any significant improvements in the coefficient of friction (COF) under oil-lubricated conditions, but that under antifriction coated conditions, significant improvements in the friction coefficients may be achieved. Wear-based tribological tests have shown that the antifriction coating on benchmark samples was completely depleted, which greatly influenced their friction and wear behavior, since steel-steel contact occurred during testing. For the 3D-microtexture, the antifriction coating was also partially depleted; however, it accumulated itself in the microtexture which acted as a potential lubricant reservoir.
关键词： ultra-short pulsed laser,surface characterization,wear,laser microtexturing,tribological,friction,characterization
更新于2025-09-16 10:30:52
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Evaluation of laser cleaning for defouling of marine biofilm contamination on aluminum alloys
摘要： The environmental friendliness short-pulsed laser removal of marine bio?lm contamination developed on the surfaces of aluminum alloy substrates was innovatively applied. Natural bio?lms were formed using a seawater immersion method. The surface state was evaluated by considering the cleaning e?ectiveness and the harm exerted on the aluminum alloy substrate surfaces. The cleaning quality was analyzed using optical microscopy (OM), ?eld emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FT-IR). The laser-induced damage/change to the substrate surface was evaluated using laser scanning confocal microscopy (LSCM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The results indicate that a nanosecond laser can be successfully used to quickly remove marine bio?lm contamination from the surface of an aluminum substrate by instantaneous thermal ablation. No clear thermal damage can be found on the laser-cleaned aluminum surface at a lower laser ?uence (1.08 J/cm2). In addition to the cleaning of marine bio?lm contamination, a higher laser ?uence (4.14 J/cm2) can also contribute to the formation of a hierarchical micro- and nanostructured oxidized layer. It is composed of amorphous-nanocrystalline phases.
关键词： Amorphous-nanocrystal,Surface characterization,Marine bio?lm contamination,Laser cleaning,Hierarchical surface structures
更新于2025-09-16 10:30:52
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Quantitative Surface Characterization of Silicon Spheres by Combined X-Ray Fluorescence Analysis and X-Ray Photoelectron Spectroscopy Measurements
摘要： The future realization of the kilogram as the SI base unit of mass, by monocrystalline enriched 28Si-spheres requires a reliable surface analysis of silicon spheres. An analytical instrument with complementary spectroscopic techniques is used for a quantitative surface characterization of such spheres. In particular, the mass deposition and the composition of the surface layer are measured. The presented principles of the quantification combine X-ray fluorescence spectroscopy (XRF) and X-ray photoelectron spectroscopy (XPS) results.
关键词： surface characterization,spectroscopy,measurement technique,Avogadro constant,measurement standards
更新于2025-09-10 09:29:36
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Sum Frequency Generation Vibrational Spectroscopy using Evanescent Waves - towards Probing Irregular and Complex Surfaces of Mesoscopic-scale Materials
摘要： With rapid development of materials science, on-demand techniques are highly needed with the capability to characterize materials in the micrometer and nanometer scales. In this article, we show that, by employing a prism geometry, total internal reflection (TIR) sum frequency generation (SFG) vibrational spectroscopy allows for characterizing mesoscopic materials with irregular or complex surfaces. Four representative examples were presented. First, we reveal that, mechanical grinding can subtly alter the surface molecular structures of original materials. Second, spin coating can substantially change the surface molecular structures of particle samples. Third, surface restructuring of carboxylated multi-walled carbon nanotubes (c-MWCNTs) can happen in response to the surrounding environment. Fourth, surface adsorption and desorption dynamics of toluene on activated charcoal can be traced. Such experiments demonstrate, there are still a broad range of research fields ahead SFG can be directed to, where materials in mesoscopic scales with irregular or complex surfaces can be studied.
关键词： Surface Characterization,Sum Frequency Generation,Vibrational Spectroscopy,Mesoscopic-scale Materials,Evanescent Waves
更新于2025-09-10 09:29:36