scholarly journals Polychromatic polarization: Boosting the capabilities of the good old petrographic microscope

Geology ◽  
2021 ◽  
Author(s):  
Bernardo Cesare ◽  
Nicola Campomenosi ◽  
Michael Shribak
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Direct Detection ◽  
Ion Beam ◽  
Microstructural Analysis ◽  
Imaging Method ◽  
Polarizing Microscopy ◽  
Full Spectrum ◽  
Thin Sections ◽  
Color Palette

Polychromatic polarizing microscopy (PPM) is a new optical technique that allows for the inspection of materials with low birefringence, which produces retardance between 1 nm and 300 nm. In this region, where minerals display interference colors in the near-black to gray scale and where observations by conventional microscopy are limited or hampered, PPM produces a full spectrum color palette in which the hue depends on orientation of the slow axis. We applied PPM to ordinary 30 μm rock thin sections, with particular interest in the subtle birefringence of garnet due both to non-isotropic growth or to strain induced by external stresses or inclusions. The PPM produces striking, colorful images that highlight various types of microstructures that are virtually undetectable by conventional polarizing microscopy. PPM opens new avenues for microstructural analysis of geological materials. The direct detection and imaging of microstructures will provide a fast, non-destructive, and inexpensive alternative (or complement) to time-consuming and more costly scanning electron microscope–based analyses such as electron backscatter diffraction. This powerful imaging method provides a quick and better texturally constrained basis for locating targets for cutting-edge applications such as focused ion beam-transmission electron microscopy or atom probe tomography.

The reconstruction and functional mapping of a recurrent microcircuit in Drosophila mushroom body

2019 ◽  
Author(s):  
Guangxia Wang ◽  
Bangyu Zhou ◽  
Shengxiong Wang ◽  
Kai Yang ◽  
Jianjian Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Reversal Learning ◽  
Mushroom Body ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Recurrent Network ◽  
Dopamine Neurons ◽  
Imaging Method ◽  
Neural Basis ◽  
Thin Sections

AbstractIn Drosophila melanogaster, mushroom body and anterior paired lateral (APL) neurons play important roles not only in learning and memory but also in high cognitive behavior, reversal learning. The circuit between APL neurons and Kenyon cells (KCs) in the mushroom body underlies this behavior, including reversal learning, and electron microscopy (EM) methods must be used to reveal this circuit. Here, we reconstructed the connections between mushroom body cells and APL neurons in the vertical lobe of the mushroom body via focused ion beam scanning electron microscopy (FIB-SEM) and sparse genetic horseradish peroxidase (HRP) labeling. We offer the first EM evidence that recurrent network and lateral inhibition connections exist between APL neurons and KCs in the vertical lobe of the mushroom body. This circuit is the neural basis of action selection decision making, associative learning and reversal learning. Additionally, dopamine neurons project to different areas of mushroom bodies and, together with extrinsic neurons and KC axons, form a compartmental structure of mushroom body axons, thereby restricting the KC-mushroom body output neuron (MBON) response to local compartments. Whether APL neurons also respond locally is uncertain. We found that APL neurons exhibited input and output synapses that were intermixed and arranged on enlarged and thin sections, respectively, resembling a string of beads. Different KCs were found to project to APL neurons nonrepetitively, forming a local circuit structure. Furthermore, using a single neurite calcium imaging method, we identified local calcium domains on this circuit, suggestive of individual electrical compartments. The electrically recorded APL neurons were nonspike neurons that selectively responded to odor in both the lobes and calyx. Thus, the localized APL neuron responses coordinate with mushroom body–dopamine-MBON compartmental function.

scholarly journals Micro-Fabric Analyzer (MFA): A New Semiautomated ArcGIS-Based Edge Detector for Quantitative Microstructural Analysis of Rock Thin-Sections

2021 ◽  
Vol 10 (2) ◽  
pp. 51 ◽  
Author(s):  
Roberto Visalli ◽  
Gaetano Ortolano ◽  
Gaston Godard ◽  
Rosolino Cirrincione
Keyword(s):  
Physical Properties ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Image Features ◽  
Elemental Distribution ◽  
Edge Detector ◽  
Sandstone Sample ◽  
Thin Sections ◽  
X Ray ◽  
Distribution Maps

Micro-Fabric Analyzer (MFA) is a new GIS-based tool for the quantitative extrapolation of rock microstructural features that takes advantage both of the characteristics of the X-ray images and the optical image features. Most of the previously developed edge mineral grain detectors are uniquely based on the physical properties of the X-ray-, electron-, or optical-derived images; not permitting the exploitation of the specific physical properties of each image type at the same time. More advanced techniques, such as 3D microtomography, permit the reconstruction of tridimensional models of mineral fabric arrays, even though adjacent mineral grain boundaries with the same atomic density are often not detectable. Only electron backscatter diffraction (EBSD) allows providing high-performing grain boundary detection that is crystallographically differentiated per mineral phase, even though it is relatively expensive and can be executed only in duly equipped microanalytical laboratories by suitably trained users. Instead, the MFA toolbox allows quantifying fabric parameters subdivided per mineral type starting from a crossed-polarizers high-resolution RGB image, which is useful for identifying the edges of the individual grains characterizing rock fabrics. Then, this image is integrated with a set of micro-X-ray maps, which are useful for the quantitative extrapolation of elemental distribution maps. In addition, all this is achieved by means of low-cost and easy-to-use equipment. We applied the tool on amphibolite, mylonitic-paragneiss, and -tonalite samples to extrapolate the particle fabric on different metamorphic rock types, as well as on the same sandstone sample used for another edge detector, which is useful for comparing the obtained results.

scholarly journals Artificial generation of representative single Li-ion electrode particle architectures from microscopy data

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Orkun Furat ◽  
Lukas Petrich ◽  
Donal P. Finegan ◽  
David Diercks ◽  
Francois Usseglio-Viretta ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Lithium Ion ◽  
Scale Model ◽  
Multi Scale ◽  
Physics Modeling ◽  
Microscopy Data ◽  
Microscopy Techniques ◽  
Backscatter Diffraction

AbstractAccurately capturing the architecture of single lithium-ion electrode particles is necessary for understanding their performance limitations and degradation mechanisms through multi-physics modeling. Information is drawn from multimodal microscopy techniques to artificially generate LiNi0.5Mn0.3Co0.2O2 particles with full sub-particle grain detail. Statistical representations of particle architectures are derived from X-ray nano-computed tomography data supporting an ‘outer shell’ model, and sub-particle grain representations are derived from focused-ion beam electron backscatter diffraction data supporting a ‘grain’ model. A random field model used to characterize and generate the outer shells, and a random tessellation model used to characterize and generate grain architectures, are combined to form a multi-scale model for the generation of virtual electrode particles with full-grain detail. This work demonstrates the possibility of generating representative single electrode particle architectures for modeling and characterization that can guide synthesis approaches of particle architectures with enhanced performance.

scholarly journals Effect of Ion Irradiation on Nanoindentation Fracture and Deformation in Silicon Carbide

JOM ◽  
2021 ◽  
Author(s):  
Alexander J. Leide ◽  
Richard I. Todd ◽  
David E. J. Armstrong
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Compressive Residual Stresses

AbstractSilicon carbide is desirable for many nuclear applications, making it necessary to understand how it deforms after irradiation. Ion implantation combined with nanoindentation is commonly used to measure radiation-induced changes to mechanical properties; hardness and modulus can be calculated from load–displacement curves, and fracture toughness can be estimated from surface crack lengths. Further insight into indentation deformation and fracture is required to understand the observed changes to mechanical properties caused by irradiation. This paper investigates indentation deformation using high-resolution electron backscatter diffraction (HR-EBSD) and Raman spectroscopy. Significant differences exist after irradiation: fracture is suppressed by swelling-induced compressive residual stresses, and the plastically deformed region extends further from the indentation. During focused ion beam cross-sectioning, indentation cracks grow, and residual stresses are modified. The results clarify the mechanisms responsible for the modification of apparent hardness and apparent indentation toughness values caused by the compressive residual stresses in ion-implanted specimens.

Investigation of Ga ion implantation-induced damage in single-crystal 6H-SiC

2018 ◽  
Vol 1 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Zhongdu He ◽  
Zongwei Xu ◽  
Mathias Rommel ◽  
Boteng Yao ◽  
Tao Liu ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Implantation Dose ◽  
Formation Mechanisms ◽  
Schematic Model ◽  
Dose Threshold ◽  
Before And After

In order to investigate the damage in single-crystal 6H-silicon carbide (SiC) in dependence on ion implantation dose, ion implantation experiments were performed using the focused ion beam technique. Raman spectroscopy and electron backscatter diffraction were used to characterize the 6H-SiC sample before and after ion implantation. Monte Carlo simulations were applied to verify the characterization results. Surface morphology of the implantation area was characterized by the scanning electron microscope (SEM) and atomic force microscope (AFM). The ‘swelling effect’ induced by the low-dose ion implantation of 1014−1015 ions cm−2 was investigated by AFM. The typical Raman bands of single-crystal 6H-SiC were analysed before and after implantation. The study revealed that the thickness of the amorphous damage layer was increased and then became saturated with increasing ion implantation dose. The critical dose threshold (2.81 × 1014−3.26 × 1014 ions cm−2) and saturated dose threshold (˜5.31 × 1016 ions cm−2) for amorphization were determined. Damage formation mechanisms were discussed, and a schematic model was proposed to explain the damage formation.

Imaging of retina cellular and subcellular structures using ptychographic hard X-ray tomography

2021 ◽  
Vol 134 (19) ◽  
Author(s):  
Valerie Panneels ◽  
Ana Diaz ◽  
Cornelia Imsand ◽  
Manuel Guizar-Sicairos ◽  
Elisabeth Müller ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Plexiform Layer ◽  
Wild Type Mouse ◽  
Small Region ◽  
Mouse Retina ◽  
Imaging Method ◽  
Scanning Method ◽  
X Ray ◽  
Correlative Imaging

ABSTRACT Ptychographic hard X-ray computed tomography (PXCT) is a recent method allowing imaging with quantitative electron-density contrast. Here, we imaged, at cryogenic temperature and without sectioning, cellular and subcellular structures of a chemically fixed and stained wild-type mouse retina, including axons and synapses, with complete isotropic 3D information over tens of microns. Comparison with tomograms of degenerative retina from a mouse model of retinitis pigmentosa illustrates the potential of this method for analyzing disease processes like neurodegeneration at sub-200 nm resolution. As a non-destructive imaging method, PXCT is very suitable for correlative imaging. Within the outer plexiform layer containing the photoreceptor synapses, we identified somatic synapses. We used a small region inside the X-ray-imaged sample for further high-resolution focused ion beam/scanning electron microscope tomography. The subcellular structures of synapses obtained with the X-ray technique matched the electron microscopy data, demonstrating that PXCT is a powerful scanning method for tissue volumes of more than 60 cells and sensitive enough for identification of regions as small as 200 nm, which remain available for further structural and biochemical investigations.

3D-EBSD Studies of Deformation, Recrystallization and Phase Transformations

2012 ◽  
Vol 715-716 ◽  
pp. 41-50 ◽  
Author(s):  
Michael Ferry ◽  
Wan Qiang Xu ◽  
M. Zakaria Quadir ◽  
Nasima Afrin Zinnia ◽  
Kevin J. Laws ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Thermomechanical Processing ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Void Formation ◽  
Data Generation ◽  
Serial Sectioning ◽  
Resolution Electron ◽  
Plastic Forming ◽  
Backscatter Diffraction

A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. The successive EBSD maps generated by serial sectioning are combined using various post-processing methods to generate crystallographic volumes of the microstructure. This paper provides an overview of the use of 3D-EBSD in the study of various phenomena associated with thermomechanical processing of both crystalline and semi-crystalline alloys and includes investigations on the crystallographic nature of microbands, void formation at particles, phase redistribution during plastic forming, and nucleation of recrystallization within various regions of the deformation microstructure.

Microstructural Evolution of Al–Zn–Mg–Cu Alloys in Accordance with Homogenization Time

2020 ◽  
Vol 20 (11) ◽  
pp. 6890-6896
Author(s):  
Woojin An ◽  
Jaewon Heo ◽  
Dongchan Jang ◽  
Kwang Jun Euh ◽  
Im Doo Jung ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Focused Ion Beam ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Homogenization Temperature ◽  
Strain Burst ◽  
Cu Alloys ◽  
Homogenization Time ◽  
Backscatter Diffraction

The microstructural evolution of Al–Zn–Mg–Cu alloys has been investigated for the homogenization time effect on the texture, grain orientation and dislocation density. The Al–Zn–Mg–Cu alloys were casted and homogenized for 4, 8, 16 and 24 hours. Electron backscatter diffraction (EBSD) analysis was conducted to characterize the microstructural behavior. Micropillars were fabricated using focused ion beam (FIB) milling in grains of specific crystallographic orientations. Coarse precipitations in the grain boundaries are S (Al2CuMg) and T (Al2Mg3Zn3) phases verified by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) observation. With increasing homogenization time, equiaxed cell sizes increased. The volume fraction of S and T phases decreased with the diffusion of atomic elements into matrix. The Vickers hardness and tensile strength values decreased with homogenization temperature. The micropillar compression analysis was compared to macro tensile test results to understand the size effect and strain burst phenomenon on the mechanical properties of Al–Zn–Mg–Cu alloys.

The Application of 3D-EBSD for Investigating Texture Development in Metals and Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 469-474
Author(s):  
Michael Ferry ◽  
M. Zakaria Quadir ◽  
Nasima Afrin Zinnia ◽  
Lori Bassman ◽  
Cassandra George ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Low Carbon Steel ◽  
Texture Development ◽  
Data Generation ◽  
Low Carbon ◽  
Resolution Electron ◽  
Multi Phase ◽  
Backscatter Diffraction

A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. However, there are several challenges facing the technique including the need for accurate reconstruction of the EBSD slice data and the development of methods for representing the myriad microstructural features of interest including, for example, orientation gradients arising from plastic deformation through to the structure of grains and their interfaces in both single-phase and multi-phase materials. This paper provides an overview of the use of 3D-EBSD in the study of texture development in alloys during deformation and annealing and includes an update on current research on the crystallographic nature of microbands in some body centred and face centred cubic alloys and the nucleation and growth of grains in an extra low carbon steel.

Intergrowth Structure of Zeolite Crystals and Pore Orientation of Individual Subunits Revealed by Electron Backscatter Diffraction/Focused Ion Beam Experiments

2008 ◽  
Vol 47 (30) ◽  
pp. 5637-5640 ◽  
Author(s):  
Eli Stavitski ◽  
Martyn R. Drury ◽  
D. A. Matthijs de Winter ◽  
Marianne H. F. Kox ◽  
Bert M. Weckhuysen
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Zeolite Crystals
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