Wide Range Of Magnifications Research Articles

A Highly Integrated AFM-SEM Correlative Analysis Platform

Abstract We describe the first truly correlative atomic force micro­scopy-scanning electron microscopy (AFM-SEM) platform designed from first principles and from the ground up for the study of sample properties under a wide range of magnifications. Combining these two microscopy techniques, “in situ,” into a highly integrated workstation opens unprecedented measurement capabilities at the nanoscale, while simplifying experiment workflows to yield a higher level of data throughput. Unlike SEM, the AFM offers true three-dimensional topo­graphy images, something SEM can only provide indirectly. This allows for the characterization of nano-mechanical properties, as well as for magnetic and electrical characterization of samples, which are increasingly of interest in material science, multi-component technologies (that is, solar cell and battery research), and pharmaceutical investigations. On the other hand, the SEM’s wide field-of-view is critical in identifying regions of interest with feature sizes of less than a micron, which are notoriously difficult to find over large spatial scales in conventional AFM systems. In addition, the SEM’s ability to visualize the AFM tip facilitates its navigation to aid the characterization of samples with challenging three-dimensional topographies. In this paper, we describe the major elements of the system design and demonstrate how correlative microscopy can help the characterization of samples with challenging morphologies such as the edge of a razor blade or the nanomechanical analysis of platinum nanopillars.

Analysis of material composition with energy dispersive of X-ray spectroscopy method

ZnO is a semiconductor material with an energy band gap of 3.37 eV at room temperature, this causes ZnO to work in the UV light range. In this study, ZnO material doped with Nitrogen with a doping percentage was 10%. Deposition of ZnO: N material was carried out on a glass substrate using a spray coating technique. A composition test was performed using SEM-EDX. SEM-EDX is a device that has a wide magnification range to observe a sample from an overall view, with images of nanostructures at very high magnification. SEM-EDX serves to analyze topography, morphology, composition, and scale information from SEM image images on a material. Composition testing using SEM-EDX tools can result in pure impurity, pure oxide, and pure. For the results of pure impurity test results were obtained in the form of elements of elements C, N, O, and Zn with a mass of 14.46%, 0.53%, 54.70%, and 30.30%. For the oxide test on ZnO doping N 10%, the results were obtained in the form of elements of N, O, and Zn elements, each with a mass of 2.45%, 19.17%, and 78.38%. For pure test on ZnO doping N 10%, the results are in the form of elements of N, O, and Zn elements, each with a mass of 0.90%, 57.80%, and 41.31%.

Development of a versatile speckle pattern of nano-sized polymer particles for high-resolution SEM-DIC

Digital image correlation (DIC) in combination with Scanning Electron Microscopy (SEM) and in-situ mechanical testing has great potential to study the micro-mechanical behavior of materials. Yet, the application of a high-quality speckle pattern for DIC remains challenging at this scale. Here, we present a versatile polymer particle-based speckle pattern with adjustable speckle size (0.17–1.04 μm) to cover a wide range of magnifications (500x to 5000x) in SEM. This speckle does not completely cover the surface, ensuring the visibility of deformations taking place in the studied object. The quality of the pattern is analyzed to determine the precision, noise, and correctness of the results obtained by SEM-DIC. Out-of-plane displacements are also considered. Depending on the choice of speckle size and imaging parameters, high quality SEM-DIC patterns were obtained. The measurable strain with this method ranges between 0.05% up to 100%. To illustrate the versatility of the speckling method, three different micromechanical test cases on polymer materials are presented. These showed that global and local deformation can clearly be visualized at different magnifications.

Identifying Taxonomic Belonging of Animal HairUsing Instrumental and Microscopic Methods

Urgent need to develop a methodology for identifying taxonomic belonging of animal hair using modern research methods (identification of additional objective criteria in the case of a comparative research on material evidence, namely: animal hair) is considered that contributes to solving a larger range of issues raised while appointment forensic biological examination. Authors aimed to substantiate possibility of identifying the taxonomic affiliation of animal hair using instrumental and microscopic methods, in particular, scanning electron microscope, allowing forensic biologists to study the surfaces of objects of animal origin, both of significant linear dimensions, and of microparticles in a wide range of magnifications (from 10× to more than 200,000×), providing a resolution of up to 10–9 m. Obtaining a general image of the surface and selecting appropriate areas for detailing (at the maximum possible magnifications) does not require significant reconfiguration of the device. A significant depth of focus provides detailed images of various surfaces with developed relief (cracks; traces of mechanical damage; morphological specifics of periodically reproduced surface structures). Contrast is the detection result of reflected electrons (depending on the distribution of phase components differing in chemical composition the studied sample surface). The proposed method of researching animal hair will significantly expand possibilities of examination of these objects: it will reduce the time and increase the accuracy of conducting such research, as well as make it possible to supplement illustrative material (for example, microphotographs of hair cuticles of frequently encountered animal species).

A comparative study on X-ray peak broadening analysis of mechanically alloyed Al2O3 particles dispersion strengthened Al 7017 alloy

AA7017 + x vol. % Al2O3 (x = 5, 10, 20) nanocomposites powders were synthesized by HEBM process with milling time of 0 h and 20 h. The synthesized nanocomposite powders were characterized using XRD (Bruker USA D8 Advance, Davinci) with CuKα (1.5406 Aͦ), 2θ range (30°-90°), and Scan Speed (1°/min) for examining the crystalline nature of the powder samples. The size and shape of the powder particle were identified by HR-SEM (FEI Quanta FEG 200F) with 30 KV voltage, wide magnification range (12x-105 x) and secondary electron mode, and HR-TEM (JEOL Japan, JEM-2100 Plus) with voltage (200 kV), and magnification range (below 50 nm). Powder particles were measured by laser scattering technique using zeta analyzer (Laser Particle size Analyser, M/s Microtrac),and finally, the melting point and peak shift variation of composite powder samples were analyzed using TG-DSC (Netzsch TG-DSC) with temperature range (25–1400 °C), and heating rate (10 °C/min)under argon atmosphere. Furthermore, the particle sizes evaluated from different models of diffraction analysis (Scherrer, Williamson-Hall, and size-strain plot, SSP, methods) were compared with the results from PSA, HR-SEM, and HR-TEM analyses. The obtained mechanical properties explained that 20h milled AA7017 + x vol. % Al2O3 (x = 5, 10, and 20) samples produced higher values; and the properties improvement in all the samples were correlated theoretically by various strengthening mechanisms.

Разноразмерная пористость и теплопроводность оксидных слоев, сформированных плазменно-электролитическим оксидированием на силумине АК12Д

Oxide layers formed by plasma-electrolytic oxidation (PEO) are characterized by a sufficiently high porosity, which influences almost the whole complex of service characteristics. However, the known data on the integral porosity of PEO-produced layers are rather contradictory, and the nature of the pore size distribution in these layers remains understudied. As a result of processing the images of the layer cross-section produced in a wide magnification range (scanning electron microscopy – SEM, image-based analysis), the authors obtained the pore size distribution in the range of 10 nm to 10 µm, which is sufficiently well described by a lognormal distribution function (pore geometry was approximated by a spherical shape). Such distribution pattern indicates the nature of pore formation, which can be related to the thermally activated process of gas emission from a liquid melt, the volume and average temperature of which, in their turn, depend on the micro-arc discharge energy. The paper presents the results of identifying the oxide layer phase composition and crystallites sizes by the X-ray crystallography method. Comparing the results of X-ray spectral microanalysis and X-ray crystallography, the amorphous component phase composition was evaluated. Using the stationary method and the method of pulsed laser heating, the authors determined the thermal conductivity of the initial oxide layer and the layer after the removal of its highly-porous outer part. The porosity values obtained experimentally and calculated based on the analysis of SEM-images and the results of determining the phase composition, including amorphous phases, allowed evaluating the oxide layer thermal conductivity with the help of four known analytical models. The results of calculating the thermal conductivity using the Loeb model showed good convergence with the experimental results obtained in this work. The modeling demonstrated that the size of crystallites influence the oxide layer thermal conductivity much less than the porosity and amorphous phase.

How to Organize Affordable Microsurgical Training Laboratory: Optimal Price-quality Solution.

Summary:Today, microsurgery is an integral part of plastic surgery, maxillofacial surgery, hand surgery, and neurosurgery. More and more surgical procedures are accompanied by microsurgical intervention. Long training is required to develop the necessary skills for fine work with microsurgical instruments and delicate tissues under magnification. We suggest a methodology as to how to organize an inexpensive microsurgical training laboratory with minimal investment. Suggested guidelines provide information about cost-effective ways of arranging a comfortable training environment. An adapted stereoscopic microscope allows working with a wide range of magnification and focus distance. An ergonomic working position is set up by adjustable handmade table and chair. For performing basic microsurgical manipulations, a set of four instruments and inexpensive suture materials are used. A total amount of 323.5 USD was spent to purchase all of the necessary components for the microsurgical laboratory. The described components are available worldwide regardless of manufacturers. We suggest an inexpensive way to arrange a microsurgical laboratory. This approach is especially beneficial for students and residents from low-income countries.

Microstructure investigation of plant architecture with X-ray microscopy

In recent years, the plant morphology has been well studied by multiple approaches at cellular and subcellular levels. Two-dimensional (2D) microscopy techniques offer imaging of plant structures on a wide range of magnifications for researchers. However, subcellular imaging is still challenging in plant tissues like roots and seeds. Here we use a three-dimensional (3D) imaging technology based on the X-ray microscope (XRM) and analyze several plant tissues from different plant species. The XRM provides new insights into plant structures using non-destructive imaging at high-resolution and high contrast. We also utilized a workflow aiming to acquire accurate and high-quality images in the context of the whole specimen. Multiple plant samples including rice, tobacco, Arabidopsis and maize were used to display the differences of phenotypes. Our work indicates that the XRM is a powerful tool to investigate plant microstructure in high-resolution scale. Our work also provides evidence that evaluate and quantify tissue specific differences for a range of plant species. We also characterize novel plant tissue phenotypes by the XRM, such as seeds in Arabidopsis, and utilize them for novel observation measurement. Our work represents an evaluated spatial and temporal resolution solution on seed observation and screening.

TO THE QUESTION OF AN INTEGRATED RESEARCH OF BIOLOGICAL DAMAGE TO FIBROUS MATERIALS BY THE METHOD OF RASTER ELECTRON MICROSCOPY

The article considers the need for a comprehensive study of biological damage to fibrous materials by scanning electron microscopy. The main types and characteristics of fibers and fibrous materials, their types of damage, in particular, biological, and the mechanism of their formation are described. It is shown that with modern methods for studying morphological characteristics, the most effective is the method of scanning electron microscopy, which makes it possible to directly study the object in a wide range of magnifications. The use of scanning electron microscopy makes it possible to identify qualitatively new volumetric microsigns when conducting studies of fibrous materials. Biological damage agents (biofactors) are considered — microbiological (bacteria, microbes, fungi, blue-green algae), phytological (mosses, lichens, higher plants, algae), zoological (insects, birds, mammals). Attention is focused on the study of injuries caused by mold caused by moths, dogs, etc.
 Conducting a comprehensive study of various types of damage to materials of various fibrous nature allows us to obtain an information database, the possibility of differentiating chemical, mechanical, thermal and biological damage, identifying microsigns that individualize one or another object (factor) of action, influence, increasing the potential for obtaining trace information about the actual data and circumstances of the event in those cases when only by external morphological features of the diagnosis It is not possible to repair damage. The data obtained indicate the effectiveness of the chosen research area. The results of the studies are positive for creating the optimal research scheme, methods of microscopic studies of damage to materials of fibrous nature in order to solve diagnostic, identification and situational tasks of forensic examination.

Generalized spot auto-focusing method with a high-definition auto-correlation function in transmission electron microscopy.

The spot auto-focusing (AF) method with a unique high-definition auto-correlation function (HD-ACF) proposed in the previous paper is improved and is now applicable to general specimens at a wide range of magnifications. According to the definition where the AF is defocused to obtain the highest resolution, the proposed method achieves the sharpest HD-ACF profile in the AF spot image. The relationship where the sharpest HD-ACF profile gives the highest resolution is theoretically explained, and practical AF examples for different specimens and magnifications are experimentally demonstrated. Specimens include a yeast cell thin section at 10-k magnification, a standard grating replica used as a ruler at 50-k, a crystal lattice of graphitized carbon at 400-k and a 60°-tilted thin section (yeast cell) at 10-k. Different procedures are prepared to actively identify the defocus position that gives the sharpest HD-ACF profile. Every AF result demonstrates the highest-resolution image.

Grain Boundary Detection and Phase Segmentation of SEM Ferrite–Pearlite Microstructure Using SLIC and Skeletonization

In this paper, we report an efficient segmentation and grain boundary detection process using modern image processing operators like simple linear iterative clustering and skeletonization. Accurate phase segmentation is the major requirement for any phase identification and quantification operations. The proposed image processing methods have been experimented on the in-house generated 48 scanning electron microscopy (SEM) microstructures obtained from plain carbon steel samples containing 0.1, 0.22, 0.35 and 0.48 wt%C and have been subjected to both annealing and normalizing treatments. The microstructures for dataset have been captured in SEM using secondary electron mode over a wide range of magnification × 500–× 5000. The experimental results significantly validate the segmentation of ferrite and pearlite regions. Also, the grain boundary detection results appear to be plausibly effective in case of ferrite–ferrite and ferrite–pearlite boundaries. However, the grain boundary detection efficiency is found to be relatively poor in case of pearlite–pearlite boundary. The overall performance of the proposed image processing technique in context of ferrite–pearlite steel SEM images shows promising results in all circumstances of compositional range, heat treatment and magnification.

Use of cell phone type cameras to enhance focusing and magnification in optical microscopes.

Cameras with auto-focusing and zoom capability, such as those in cell phones, can simplify focusing a microscope and at the same time provide a wide range of magnification.

Influence of a silicon impurity on growth of diamond crystals in the Mg-C system

This article reports a study of the morphology of diamond crystals grown at 7.0 GPa and 1800 °C in the Mg-C system with the addition of silicon in an amount of 0.5 wt%. Step patterns on {111} and {100} faces were studied in a wide range of magnifications using optical microscopy (DIC), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Morphological studies revealed that a reduction in the growth rate and a change in the morphological significance of the {100} and {111} faces were associated with adsorption of a mobile impurity (silicon) leading to poisoning of kinks and (or) steps. This leads to roughing of the faces and formation of macrosteps as well as 2D and 3D nucleation islands. At a silicon concentration of 1.0 wt% or more, immobile impurity particles are apparently formed on macrostep terraces, and growth inhibition occurs according to the Cabrera-Vermilyea model.

ELECTRON MICROSCOPY – AN OVERVIEW

The electron microscope (EM) is one of the most widely used instruments in research laboratories and is central based to micro-structural analysis and therefore important to any investigation related to the processing. The SEM/TEM provides information relating to topographical features, morphology, phase distribution, compositional differences, crystal structure, crystal orientation, and the presence and location of various defects. The strength of the SEM lies in its inherent versatility due to the multiple signals generated, simple image formation process, wide magnification range, and excellent depth of field. Later The SEM has more than 300 times the depth of field of the light microscope. The higher magnifications of the SEM are rivaled only by the transmission electron microscope (TEM) which requires the electrons to penetrate through the entire thickness of the sample. TEM images allow researchers to view the samples on a molecular level, making it possible to analyze structures and texture clearer and resolute which is useful in the study of crystals and metals and also has industrial applications. As a result, sample preparation of bulk materials through TEM is tedious and time-consuming compared to the ease of SEM sample preparation and may also damage the microstructure.

Microtome-integrated microscope system for high sensitivity tracking of in-resin fluorescence in blocks and ultrathin sections for correlative microscopy

Many areas of biological research demand the combined use of different imaging modalities to cover a wide range of magnifications and measurements or to place fluorescent patterns into an ultrastructural context. A technically difficult problem is the efficient specimen transfer between different imaging modalities without losing the coordinates of the regions-of-interest (ROI). Here, we report a new and highly sensitive integrated system that combines a custom designed microscope with an ultramicrotome for in-resin-fluorescence detection in blocks, ribbons and sections on EM-grids. Although operating with long-distance lenses, this system achieves a very high light sensitivity. Our instrumental set-up and operating workflow are designed to investigate rare events in large tissue volumes. Applications range from studies of individual immune, stem and cancer cells to the investigation of non-uniform subcellular processes. As a use case, we present the ultrastructure of a single membrane repair patch on a muscle fiber in intact muscle in a whole animal context.

Calibration of Scanning Electron Microscopes over a Wide Range of Magnifications

A new method is proposed for calibrating scanning electron microscopes (SEM) with magnification in the 10–50000× range using an end gauge and an auxiliary structure. Use of a certified end gauge ensures traceability of the calibration results to the primary standard for the meter. The relative expanded uncertainty of measurements on an S-4800 SEM at magnifications of 1000, 10000, and 50000× is less than 0.14%.

Condenser-free contrast methods for transmitted-light microscopy.

Phase contrast microscopy allows the study of highly transparent yet detail-rich specimens by producing intensity contrast from phase objects within the sample. Presented here is a generalized phase contrast illumination schema in which condenser optics are entirely abrogated, yielding a condenser-free yet highly effective method of obtaining phase contrast in transmitted-light microscopy. A ring of light emitting diodes (LEDs) is positioned within the light-path such that observation of the objective back focal plane places the illuminating ring in appropriate conjunction with the phase ring. It is demonstrated that true Zernike phase contrast is obtained, whose geometry can be flexibly manipulated to provide an arbitrary working distance between illuminator and sample. Condenser-free phase contrast is demonstrated across a range of magnifications (4–100×), numerical apertures (0.13–1.65NA) and conventional phase positions. Also demonstrated is condenser-free darkfield microscopy as well as combinatorial contrast including Rheinberg illumination and simultaneous, colour-contrasted, brightfield, darkfield and Zernike phase contrast. By providing enhanced and arbitrary working space above the preparation, a range of concurrent imaging and electrophysiological techniques will be technically facilitated. Condenser-free phase contrast is demonstrated in conjunction with scanning ion conductance microscopy (SICM), using a notched ring to admit the scanned probe. The compact, versatile LED illumination schema will further lend itself to novel next-generation transmitted-light microscopy designs. The condenser-free illumination method, using rings of independent or radially-scanned emitters, may be exploited in future in other electromagnetic wavebands, including X-rays or the infrared.

High-accuracy magnification calibration for a microscope based on an improved discrete Fourier transform

Microscopes are widely applied in characterizing feature sizes at the micro-/nanoscale, and magnification calibration plays a key role in achieving precise measurements. However, it is difficult to obtain accurate results by using the general magnification calibration method if comparing the displayed size of a test-piece under microscope and its original one. In this study, a high-accuracy and automatic magnification calibration method that could be applied to different types of microscopes is proposed. A standard grating is employed as the reference, and a high-resolution discrete Fourier transform is used to analyze the images captured under various magnifications in this method. With utilization of the high-order harmonic component in the Fourier spectrum, the proposed method is capable of performing the calibration over a wide range of magnifications while maintaining identical precision. The relative error of the proposed method can be theoretically limited to 0.01%; moreover, the image noise can be tolerated. Furthermore, the validation and extensive adaptability of this method are demonstrated by calibrating the magnification of a scanning electron microscope and an optical microscope.

A new X-ray pinhole camera for energy dispersive X-ray fluorescence imaging with high-energy and high-spatial resolution

A new X-ray pinhole camera for the Energy Dispersive X-ray Fluorescence (ED-XRF) imaging of materials with high-energy and high-spatial resolution, was designed and developed. It consists of a back-illuminated and deep depleted CCD detector (composed of 1024×1024pixels with a lateral size of 13μm) coupled to a 70μm laser-drilled pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values.The characteristic X-ray fluorescence is induced on the samples by irradiation with an external X-ray tube working at a maximum power of 100W (50kV and 2mA operating conditions).The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated. Energy response and energy calibration of the CCD detector were determined by irradiating pure target-materials emitting characteristic X-rays in the energy working-domain of the system (between 3keV and 30keV).Measurements were performed by using a multi-frame acquisition in single-photon counting. The characteristic X-ray spectra were obtained by an automated processing of the acquired images. The energy resolution measured at the Fe–Kα line is 157eV.The use of the X-ray pinhole camera for the 2D resolved elemental analysis was investigated by using reference-patterns of different materials and geometries. The possibility of the elemental mapping of samples up to an area of 3×3cm2 was demonstrated.Finally, the spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. The spatial resolution determined at the magnification values of 3.2× and 0.8× (used as testing values) is about 90μm and 190μm respectively.

Structural Aspects of the Behavior of Lead-Free Solder in the Corrosive Solution

In oxidizing environments, most tin-based lead (Pb)-free alloys form a tin oxide that is easily eroded or mechanically damaged, affecting corrosion resistance and thus reliability of the soldered joints. In this study, the effect of microstructure heterogeneity on corrosion behavior of Pb-free solder candidate systems has been investigated on the example of as-cast and heat-treated alloys. The research was focused on a comparison between the corrosion resistance of binary Sn-Zn and ternary Sn-Zn-Cu alloys. Accelerated corrosion tests were performed by means of electrochemical methods in the sodium sulfate solution (VI), Na2SO4, of about 0.5 M concentration, pH adjusted to 2 by means of concentrated H2SO4 acid. In these tests, the corrosion potentials as well as polarization curves were determined for the selected alloys in as-cast state and after their heat treatment using different combinations of processing parameters. The measurements of basic electrochemical characteristics were made, i.e., the corrosion current (i corr μA/cm2) and Tafel coefficients, both cathodic (b c V/dec) and anodic (b a V/dec) ones. Detailed structural characterization of as-cast and heat-treated alloys before and after accelerated corrosion tests has been made under a wide range of magnifications using light microscopy and scanning electron microscopy observations. The results showed that structural heterogeneity of the examined alloys, attributed to the presence of secondary phases, and affected by their size and distribution, significantly influences the behavior of the examined Pb-free Sn-Zn-based alloys in the corrosive environment.