Surface Topography Of Samples Research Articles

Mapping metabolites from rough terrain: laser ablation electrospray ionization on non-flat samples

A laser ablation electrospray ionization (LAESI) source was custom-built to accommodate the topography of non-flat sample surfaces. Reproducible ablation mark diameters of 69 ± 7 μm in average have been achieved.

Assessment of morphology, topography and chemical composition of water-repellent films based on polystyrene/titanium dioxide nanocomposites

In this study, polystyrene (PS)/titanium dioxide (TiO2) films were fabricated through simple solution casting technique via a modified phase separation process. The presented approach resulted in a remarkable reduction in the required amount of nanoparticles for achieving superhydrophobicity. Scanning electron microscopy (SEM) and 3D confocal microscopy were utilized to characterize surface morphology and topography of samples, respectively. An attempt was made to give an in-depth analysis on the surface rough structure using 3D roughness profiles. It was found that high inclusions of non-solvent and nanoparticles resulted in a stable self-cleaning behavior due to the strong presence of hydrophobic TiO2 nanoparticles on the surface. Quite unexpectedly, low inclusions of nanoparticles and non-solvent also resulted in superhydrophobic property mainly due to the proper level of induced surface roughness. XPS analysis was also utilized to determine the chemical composition of the films’ surfaces. The results of falling drop experiments showed that the sample containing a higher level of nanoparticles had a much lower mechanical resistance against the induced harsh conditions. All in all, the presented method has shown promising potential in fabrication of superhydrophobic surfaces with self-cleaning behavior using the lowest content of nanoparticles.

Discharge Breakdown Characteristics With Fluorinated Polyimide Films in High-Temperature Superconducting Cable Insulation

The application of high-temperature superconducting cable now has been in the process of being implemented in power system. Polyimide (PI) film has been used as insulation in the high-temperature superconducting cable systems with the advantage of good performance in low temperature, excellent mechanical properties, and dielectric properties. However, due to the organic properties of PI films, it can be aged even brake down in the service of HTS cable. It is found that partial discharge in HTS cable can lead to insulation material degradation and finally breakdown. Our recent researches have shown that fluorination can influence the surface charge behaviors thus influence the PD characteristics of modified PI films. In this paper, PI films were fluorinated in laboratory, the relationship between the fluorination time and discharge characteristics of the films were researched. The surface topography of direct-fluorinated samples were obverted by using an Atomic force acoustic microscope. It can be found from the experiment results that the discharge times and quantity both showed decreasing tendency with the fluorination time increasing. The discharge breakdown voltage shows increasing tendency with the fluorination time from zero minutes to forty-five minutes, and then shows decreasing tendency.

The three-dimensional elemental distribution based on the surface topography by confocal 3D-XRF analysis

Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. However, it has rarely been applied to analyse surface topography and 3D elemental mapping in surface morphology. In this study, a surface adaptive algorithm using the progressive approximation method was designed to obtain surface topography. A series of 3D elemental mapping analyses in surface morphology were performed in laboratories to analyse painted pottery fragments from the Majiayao Culture (3300–2900 BC). To the best of our knowledge, for the first time, sample surface topography and 3D elemental mapping were simultaneously obtained. Besides, component and depth analyses were also performed using synchrotron radiation confocal 3D-XRF and tabletop confocal 3D-XRF, respectively. The depth profiles showed that the sample has a layered structure. The 3D elemental mapping showed that the red pigment, black pigment, and pottery coat contain a large amount of Fe, Mn, and Ca, respectively. From the 3D elemental mapping analyses at different depths, a 3D rendering was obtained, clearly showing the 3D distributions of the red pigment, black pigment, and pottery coat. Compared with conventional 3D scanning, this method is time-efficient for analysing 3D elemental distributions and hence especially suitable for samples with non-flat surfaces.

The Alkaline Dissolution Rate of Calcite.

Due to the widespread presence of calcium carbonate on Earth, several geochemical systems, among which is the global CO2 cycle, are controlled to a large extent by the dissolution and precipitation of this mineral. For this reason, the dissolution of calcite has been thoroughly investigated for decades. Despite this intense activity, a consensual value of the dissolution rate of calcite has not been found yet. We show here that the inconsistency between the reported values stems mainly from the variability of the chemical and hydrodynamic conditions of measurement. The spreading of the values, when compared in identical conditions, is much less than expected and is interpreted in terms of sample surface topography. This analysis leads us to propose benchmark values of the alkaline dissolution rate of calcite compatible with all the published values, and a method to use them in various chemical and hydrodynamic contexts.

Determination of sample surface topography using electron back-scatter diffraction patterns

The background of an electron backscattered diffraction pattern contains quantitative surface topography data. We propose a new approach to extract this topography from the location of the maximum background intensity in each diffraction pattern. Using specular reflection as a zero-th order approximation, we employ Monte Carlo simulations to determine corrections to the scattering angles, which then allow us to accurately determine the local surface normal. We derive the theoretical model and illustrate the approach experimentally using a β-Sn sphere, for which we determine the local surface normal orientation from the background intensity shifts in electron backscatter diffraction patterns.

Correlation-steered scanning for scanning probe microscopes to overcome thermal drift for ultra-long time scanning

The thermal effect is one of the most important factors that influence the accuracy of nanoscale measurement and the surface topography of samples in scanning probe microscopes (SPMs). We propose a method called correlation-steered scanning, which is capable of overcoming three-dimensional thermal drifts in real time for ultra-long time scanned images. The image is scanned band by band with overlapping parts between adjacent bands. The vertical drift can be considered as linear and can thus be eliminated together with the tilt of the sample by applying the flattening method. Each band is artificially divided into several blocks for conveniently calculating lateral drifts on the basis of the overlapping area of adjacent bands through digital image correlation. The calculated lateral drifts are compensated to steer the scanning of the subsequent blocks, thus ensuring that all bands are parallel to one another. Experimental results proved that images scanned by the proposed method exhibited less distortions than those obtained from the traditional raster scanning method. The nanoscale measurement results based on the image obtained by the proposed method also showed high accuracy, with an error of less than 1.5%. By scanning as many bands as needed, the correlation-steered scanning method can obtain a highly precise SPM image of an ultra-large area.

Green synthesis of gold nanoparticles: Its effect on cocoon and silk traits of mulberry silkworm (Bombyx mori L.)

ABSTRACTIn the present century the small particles are unique phenomenon which can be developed by bottom-up and top-down processes. These small particles may be considered as nanoparticles which help to build up a technology called nanotechnology. Nanomaterials are those materials which possess the length scales below 100 nm and quite often they make a comparison with a human hair, which is about 80,000 nm wide. We have introduced this technology, specially the green synthesis of gold (Au) nanoparticles in silkworm (Bombyx mori L.). The gold nanoparticles clearly indicate that they have a tremendous effect on enhancement of silk proteins and thus the enhancement of the cocoon weight in silkworms. Gold nanoparticles were prepared from onion, Allium cepa L. The extracted green gold nanomaterials from A. cepa were confirmed by UV-Vis spectrophotometer, XRD, FTIR, SEM, TEM and AFM. The function of green gold nanomaterials extracted from A. cepa was tested on silkworm physiology. We have used UV for judgment of the nature of particles and spectrum peak wavelength showed an absorption peak at 535 nm and indicated the wavelength of the surface plasmon resonance in gold nanoparticles (Au NPs). In blank solutions no such absorption peak was observed at 535 nm. Moreover, the gold (Au) XRD spectrum is supposed to and does demonstrate (111), (200), (220), and (311) peaks in the assortment of superimpose on the background. The process includes the (002) trace graphite peaks, where the (111) peak appears to be exceptionally sharp and strong which helps to propose that it is gold in nature. The FTIR shows that the examined particles are gold in nature. In SEM where electrons interact with atoms in the sample, producing various signals that can be detected and that hold information about the sample's surface topography and composition. The electron beam in SEM is generally scanned in a raster scan pattern, and therefore the beam's position is combined and detects the signal to produce an image. SEM can attain a resolution better than 1 nanometer size. The transmission electron microscope helps to accelerate the electrons as a source of elucidation. The AFM measurement is made in three dimensions process and thus it may be measured as horizontal to X-Y plane. Therefore, decree (magnification) measured at Z–direction, which is normally higher than X-Y. The said repulsive force is major one in AFM. Thus the tip and sample may considered to be the specific force in AFM which may measured at Z–direction. The effect of green gold nanoparticles on mulberry silkworm (Bombyx mori L) can exaggerated the silkworm physiological function. Larvae at 50, 100, 200, and 300 ppm doses were studied right from 1st stage to 5th instar stage. Gold nano treatment resulted in significant alterations in the percentage of fibroin and sericin proteins in the 5th instar as compared to that of control. At a 300 ppm dose of green nano gold the percentage of fibroin was 78.07, while sericin decreased from 39.46 (control) to 21.92. It was observed that the green gold nanomaterials have the ability to not only alter the fibroin protein but also enhance the cocoon and silk traits. The aim of this study was to investigate the effect of extra foliation of mulberry leaves with G-GNPs extracted from A. cepa on larval duration, mature silk gland weight, pupal weight, cocoon weight, cocoon shell weight, fibroin and sericins contents, etc. Moreover, the enhanced production of fibroin will explore a new venture in bioengineering and also in biomedical field.

Surface topography of CVD-W coatings on graphite substrate with a PVD-Si intermediate layer after thermal fatigue testing

This work deals with the effects of thermal fatigue testing on the surface topography of W coatings on graphite substrate with Si intermediate layers, where W coatings were deposited by chemical vapor deposition (CVD-W coatings) and Si intermediate layers were prepared by physical vapor deposition (PVD-Si layers). The surface topography of samples both as-deposited and after thermal fatigue testing were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Comparative studies show that CVD-W coatings have so excellent thermal conductivity that electronic beams are only absorbed by a thin layer on the coating surface. The absorbed thermal loads give rise to the melting of the pyramid-like W grain tips and the formation of shallow melting pools. Meanwhile, the size of the recrystallized grains on the surface is much smaller than those of the initial grains after cooling. Since the fine recrystallized grains can undoubtedly suppress the crack propagation, no visible failure was found in sample after thermal fatigue testing.

Topographical and Chemical Imaging of a Phase Separated Polymer Using a Combined Atomic Force Microscopy/Infrared Spectroscopy/Mass Spectrometry Platform.

In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry. The infrared chemical imaging component of the system utilized photothermal expansion of the sample at the tip of the atomic force microscopy probe recorded at infrared wave numbers specific to the different surface constituents. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for thermolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. The basic instrumental setup, operation, and image correlation procedures are discussed, and the multimodal imaging capability and utility are demonstrated using a phase separated poly(2-vinylpyridine)/poly(methyl methacrylate) polymer thin film. The topography and both the infrared and mass spectral chemical images showed that the valley regions of the thin film surface were comprised primarily of poly(2-vinylpyridine) and hill or plateau regions were primarily poly(methyl methacrylate). The spatial resolution of the mass spectral chemical images was estimated to be 1.6 μm based on the ability to distinguish surface features in those images that were also observed in the topography and infrared images of the same surface.

Impact of Annealing Treatment on the Behaviour of Titanium Dioxide Nanotube Layers

In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO2. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample; this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO2 nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.

New method for thickness determination and microscopic imaging of graphene-like two-dimensional materials**Project supported by the State Key Development Program for Basic Research of China (Nos. 2012CB921304, 2013CB632805, 2012CB619306) and the National Natural Science Foundation of China (No. 61474114).

We employed the microscopic reflectance difference spectroscopy (micro-RDS) to determine the layer-number and microscopically image the surface topography of graphene and MoS2 samples. The contrast image shows the efficiency and reliability of this new clipping technique. As a low-cost, quantifiable, no-contact and non-destructive method, it is not concerned with the characteristic signal of certain materials and can be applied to arbitrary substrates. Therefore it is a perfect candidate for characterizing the thickness of graphene-like two-dimensional materials.

A Trace and Retrace Scanning Combined Topography Reconstruction Strategy for Fast Scanning Atomic Force Microscopies

For nearly all atomic force microscopies (AFMs) utilized now, only the signals in trace scanning process are employed to reconstruct the sample surface topography, while the data of retrace scanning process are just used for adjustment. In this paper, a novel trace and retrace scanning combined (TRSC) topography reconstruction strategy, which successfully utilizes data from both trace and retrace processes, is proposed for AFMs to increase the surface reconstruction accuracy. Specifically, two reconstructed topography images are obtained, one is for trace scanning, and the other is for retrace scanning; the hysteresis distortion is successfully compensated with a data fusion-based postprocessing method; the alignment for trace and retrace images is further guaranteed with a feature point-based strategy; then the two images are combined together with confidence levels to reconstruct the final accurate topography image. Compared with the conventional scanning method, the proposed TRSC imaging algorithm provides much more accurate image for the sample surface, and it is especially valid for high-speed scanning tasks. Some simulation and experimental results are included to demonstrate the superior performance of the proposed imaging method.

Effects of substrate temperature on the properties of sputtered TiN thin films

In the present work, high quality nanostructured thin films of titanium nitride with nanoscale grain sizes have been prepared by the reactive magnetron sputtering method examining the effects of the substrate temperature on the topography, optical and semiconductor properties of the thin films Concretely, the three dimension surface topography of samples was investigated by atomic force microscopy determining the power spectral density functions. Also, a new revised version of the Tauc’s method (named ineffective thickness method) has been proposed for the determination of the optical band gap in nanostructure semiconductor thin films. These studies indicated that the increment of the substrate temperature improves the physical properties of the films modifying the grain size and grain aggregation, and altering the optical band gap of the samples from 4.06 to 3.43 eV. In addition, a competitive growth of crystalline planes with different orientations was found as a result of the occurrence of higher grain sizes in the nanostructured titanium nitride thin films.

Atomic force microscopy of starch systems

ABSTRACTAtomic force microscopy (AFM) generates information on topography, adhesion, and elasticity of sample surface by touching with a tip. Under suitable experimental settings, AFM can image biopolymers of few nanometers. Starch is a major food and industrial component. AFM has been used to probe the morphology, properties, modifications, and interactions of starches from diverse botanical origins at both micro- and nano-structural levels. The structural information obtained by AFM supports the blocklet structure of the granules, and provides qualitative and quantitative basis for some physicochemical properties of diverse starch systems. It becomes evident that AFM can complement other microscopic techniques to provide novel structural insights for starch systems.

Measuring intrinsic thickness of rough membranes: application to nanofibrillated cellulose films

Adequate measurement of thickness of sheet-like materials or membranes is most important for quantifying their properties such as density, barrier properties and mechanical strength. Depending on the surface roughness of the membrane, the thickness measured by standard micrometre devices (apparent thickness) may considerably overestimate the actual geometrical mean thickness (intrinsic thickness) required for such purposes. In this work, we present a method for correcting the measured apparent thickness value of thin membranes for their surface roughness, thereby obtaining an improved estimate of the intrinsic thickness. The surface roughness data required for the correction can be obtained by common surface profiling techniques. The method includes a calibration parameter, the value of which can be found experimentally by independent measurements, or can be estimated theoretically using results from standard mechanical contact theory. The method is tested on a set of nanofibrillated cellulose films with varying roughness levels controlled by pulp fibre content. The surface topography of film samples was measured using laser profilometry, and the method was calibrated experimentally using data from X-ray microtomographic images for one type of film. The intrinsic thickness estimates given by the new method are generally in good accordance with independent results obtained from X-ray microtomography.

Characterisation of orange peel on highly polished steel surfaces

The surface quality of high gloss polished steel sheets with respect to ‘orange peel’ is studied. This is motivated by the fact that workpieces are ranked solely on the visual appearance of finished surfaces according to the observed degree of orange peel. Here, to quantify the degree of orange peel, surface topographies of industrial samples are acquired by means of phase shifting interferometry, from which various surface roughness parameters are calculated. These parameters are related to qualitative aspects of the surface using the Spearman’s rank correlation coefficient. Two surface roughness parameters were identified as necessary for the evaluation of orange peel, suggesting that traditional methods can be replaced with suitable parameters that improve quality control procedures at the industry.

Stress-Dependent Electrical Contact Resistance at Fractal Rough Surfaces

AbstractThe electrical contact resistance between contacting rough surfaces was studied under various compressive stresses. The samples considered here were isotropically roughened aluminium disks with upper and lower surfaces modified through polishing and sand blasting using different sized glass beads. Fractal geometry and roughness descriptors, including root mean square values of roughness and slope, were used to describe the topography of sample surfaces, based on the digitized profiles obtained from interferometry-based profilometry. The electrical contact resistances at the interfaces were obtained by applying a controlled current and measuring the resulting voltage, through the following scenarios: (1) over time for various applied testing currents, the resistance relaxation curves were measured at constant loads; (2) through voltage-current characteristics by means of a logarithmic sweeping current, the influence of the testing current on the electrical response of contacting rough surfaces was ...

FEM analysis of the vibrational motion of oblique piezoelectric microcantilever in the vicinity of a sample surface in liquid

This article examines an oblique Microcantilever (MC) with an extended piezoelectric layer in liquid. The study of hydrodynamic force in MC which has been floated in viscous fluid is considered as paramount importance. To model the Vibrational motion, the Hamilton's principle has been used. For this purpose, the Vibrational motion equation has been modeled by considering the continuous beam based on the Euler–Bernoulli beam theory in liquid. Furthermore, using the Galerkin method and the Newmark algorithm, the differential equations of the MC has been solved. In this modeling, the inter-atomic forces between the MC tip and the sample surface have been considered in addition to the hydrodynamic and squeeze forces. The simulation results illustrate a reduction in the sensitivity of the vibrational motion under the effect of the squeeze force during the angularization of the MC. Moreover, the results illustrate that by reducing the MC distance from the sample surface, the Vibration amplitude decreases due to the increase in the fluid squeeze force. At the end, it has been shown that the time delay in sample surface topography in liquid substantially decreases in comparison with the air.

SYNTHESIZING AND CHARACTERIZING A WATERBORNE POLYANILINE FOR CORROSION PROTECTION OF STEELS

This study explores the idea of synthesizing and characterizing a new intrinsically conducting polyaniline that at the molecular level carries a hydrophilic component, making the polymer highly waterborne and thereby applicable to massive production for corrosion protection of steels. The waterborne polyaniline was mixed in a water-based epoxy and then coated on SAE 1008/1010 steel samples for evaluating its anti-corrosion capacity using a powerful surface-analysis tool, Scanning Kelvin Probe Force Microscopy (SKPFM). The high resolution surface topography and corrosion potential of steel samples coated with the Polyaniline-based primer, as studied by SKPFM, show significantly lower corrosion activities than two control groups: uncoated steel samples and epoxy-only coated samples that were also subjected to SKPFM analyses under the same corrosive condition. The surface analysis results indicate that this new waterborne polyaniline is capable of protecting steels from corrosion when mixed in conventional water-based epoxies, opening the door to the development of an economical and long-life coating for corrosion protection of steel structures.