The Experts below are selected from a list of 26619 Experts worldwide ranked by ideXlab platform
Gilbert G Ahlstrand - One of the best experts on this subject based on the ideXlab platform.
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giant Electron dense chains clusters and granules in megakaryocytes and platelets with normal dense bodies an inherited thrombocytopenic disorder iii platelet Analytical Electron Microscopy
Platelets, 2011Co-Authors: James G White, Gilbert G AhlstrandAbstract:A woman and her son were referred because of prolonged thrombocytopenia. Ultrastructural studies revealed the presence of giant organelles in their cells never observed previously in human platelets. Our initial reports described the evolution of two types of giant organelles in patient megakaryocytes and platelets. The last report also demonstrated that the large organelles in platelet whole mount preparations were inherently Electron opaque like serotonin-rich dense bodies in normal and patient platelets. In the present study Analytical Electron Microscopy of whole mount preparations from the patients and controls revealed that the inherently Electron opaque dense and hexagonal precursor fragments, chains, clusters and giant organelles contained high concentrations of calcium and phosphorous, the major elements in normal dense bodies. The ratio of calcium to phosphorous in patient giant organelles was nearly the same as in normal platelet dense bodies. However, as shown in the previous study, levels of ...
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giant Electron dense chains clusters and granules in megakaryocytes and platelets with normal dense bodies an inherited thrombocytopenic disorder iv ultrastructural cytochemistry and Analytical Electron Microscopy
Platelets, 2003Co-Authors: James G White, Gilbert G AhlstrandAbstract:Platelets from a mother and son with prolonged thrombocytopenia were shown in previous studies to contain giant organelles that developed in megakaryocytes and continued to evolve in circulating cells. Whole mount platelet preparations revealed that the large organelles were Electron opaque like the serotonin-rich dense bodies in normal and patient platelets, and Analytical Electron Microscopy revealed they contained large amounts of calcium and phosphorous in a ratio close to that found in normal platelet dense bodies. However, differences in physiology, biochemistry and morphology indicated the large opaque bodies and target-organelles in patient platelets were not aberrant dense bodies. The present study has shown that the giant organelles contain peroxidase activity like primary lysosomes in polymorphonuclear (PMN) leukocytes. Further, the giant organelles in patient platelets contain acid phosphatase activity. Analytical Electron Microscopy demonstrated that cerium, the capture ion for the acid phosp...
Gianluigi A. Botton - One of the best experts on this subject based on the ideXlab platform.
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effects of boundary migration and pinning particles on intergranular oxidation revealed by 2d and 3d Analytical Electron Microscopy
Acta Materialia, 2017Co-Authors: Brian Langelier, S Y Persaud, A Korinek, Travis Casagrande, R C Newman, Gianluigi A. BottonAbstract:Abstract To evaluate the beneficial effects of intergranular carbides on inhibiting stress corrosion cracking (SCC), Alloy 600 samples in the thermally-treated (TT) and solution-annealed (SA) conditions were analyzed after exposure to 480 °C hydrogenated steam. Intergranular oxidation was observed in both samples, along with diffusion-induced grain boundary migration (DIGM). Compositional mapping revealed DIGM to be more severe in 600SA, while conventional intergranular solute diffusion involving static boundaries appeared dominant in 600TT. 3D serial sectioning of the boundaries revealed strong variations in the intergranular oxide for 600TT, particularly in the depth of oxide penetration. This was attributed to Cr carbide precipitates, present due to the thermal treatment, pinning against DIGM. Immobilizing the boundary via carbide pinning reduces oxide growth by effectively starving it of the ready solute supply otherwise available to a migrating boundary. Because of this interaction between boundary migration, carbide pinning, and oxide growth, the intergranular oxidation in 600TT is highly variable and discontinuous compared to 600SA, where DIGM is unchecked and easier oxide growth produces near-uniform coverage of the boundary. This marked decrease in boundary oxide coverage likely contributes to the improved SCC resistance of 600TT. These results demonstrate the necessity of investigating such phenomena using 3D analysis methods.
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Multivariate-aided mapping of rare-earth partitioning in a wrought magnesium alloy
Scripta Materialia, 2016Co-Authors: David Rossouw, Andrew Scullion, Brian Langelier, Mohsen Danaie, Gianluigi A. BottonAbstract:The formability of wrought magnesium alloys can be dramatically improved by the addition of trace rare-earth elements, which can weaken the recrystallized texture. Improving the understanding of this texture-weakening mechanism requires knowledge of the precise location of the solute species in the microstructure. Here we study the partitioning of the trace alloying elements in a rare-earth magnesium alloy using Analytical Electron Microscopy and atom probe tomography, combined with multivariate statistical methods. The analysis reveals partitioning of solutes to grain boundaries and precipitate-matrix interfaces.
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Analytical Electron Microscopy of a crack tip extracted from a stressed alloy 800 sample exposed to an acid sulfate environment
Micron, 2014Co-Authors: S Y Persaud, Gianluigi A. Botton, A Korinek, Anatolie G Carcea, J Huang, R C NewmanAbstract:Abstract Alloy 800 (Fe–21Cr–33Ni) has been found susceptible to cracking in acid sulfate environments, but the mechanism is not well understood. Alloy 800 C-ring samples were exposed to an acid sulfate environment at 315 °C and cracks were found with depths in excess of 300 μm after 60 h. Preparation of a TEM sample containing crack tips is challenging, but the ability to perform high-resolution Microscopy at the crack tip would lend insight to the mechanism of acid sulfate stress corrosion cracking (AcSCC). The lift-out technique combined with a focused ion beam sample preparation was used to extract a crack tip along the cross-section of an acid sulfate crack in an Alloy 800 C-ring. TEM elemental analysis was done using EDS and EELS which identified a duplex oxide within the crack; an inner oxide consisting of a thin 3–4 nm Cr-rich oxide and an outer oxide enriched in Fe and Cr. Preliminary conclusions and hypotheses resulted with respect to the mechanism of AcSCC in Alloy 800.
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the role of aluminum distribution on the local corrosion resistance of the microstructure in a sand cast am50 alloy
Corrosion Science, 2013Co-Authors: Mohsen Danaie, Robert Matthew Asmussen, Pellumb Jakupi, David W Shoesmith, Gianluigi A. BottonAbstract:Abstract Site-specific Analytical Electron Microscopy was performed on a corroded sand-cast AM50 alloy. Areas close to partially divorced eutectic were the regions with less corrosion damage. The corrosion product layer in these areas consisted of a columnar section of predominantly amorphous MgO. At the alloy interface, an aluminum-rich layer was identified. Electron energy-loss spectroscopy suggests this layer is metallic in character. The corrosion product film on the primary α-Mg grains possessed a bi-layer morphology: a thin columnar film and a thicker, porous sub-layer. The formation of the Al-rich layer depends on the Al content in solid solution at a specific location.
James G White - One of the best experts on this subject based on the ideXlab platform.
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giant Electron dense chains clusters and granules in megakaryocytes and platelets with normal dense bodies an inherited thrombocytopenic disorder iii platelet Analytical Electron Microscopy
Platelets, 2011Co-Authors: James G White, Gilbert G AhlstrandAbstract:A woman and her son were referred because of prolonged thrombocytopenia. Ultrastructural studies revealed the presence of giant organelles in their cells never observed previously in human platelets. Our initial reports described the evolution of two types of giant organelles in patient megakaryocytes and platelets. The last report also demonstrated that the large organelles in platelet whole mount preparations were inherently Electron opaque like serotonin-rich dense bodies in normal and patient platelets. In the present study Analytical Electron Microscopy of whole mount preparations from the patients and controls revealed that the inherently Electron opaque dense and hexagonal precursor fragments, chains, clusters and giant organelles contained high concentrations of calcium and phosphorous, the major elements in normal dense bodies. The ratio of calcium to phosphorous in patient giant organelles was nearly the same as in normal platelet dense bodies. However, as shown in the previous study, levels of ...
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giant Electron dense chains clusters and granules in megakaryocytes and platelets with normal dense bodies an inherited thrombocytopenic disorder iv ultrastructural cytochemistry and Analytical Electron Microscopy
Platelets, 2003Co-Authors: James G White, Gilbert G AhlstrandAbstract:Platelets from a mother and son with prolonged thrombocytopenia were shown in previous studies to contain giant organelles that developed in megakaryocytes and continued to evolve in circulating cells. Whole mount platelet preparations revealed that the large organelles were Electron opaque like the serotonin-rich dense bodies in normal and patient platelets, and Analytical Electron Microscopy revealed they contained large amounts of calcium and phosphorous in a ratio close to that found in normal platelet dense bodies. However, differences in physiology, biochemistry and morphology indicated the large opaque bodies and target-organelles in patient platelets were not aberrant dense bodies. The present study has shown that the giant organelles contain peroxidase activity like primary lysosomes in polymorphonuclear (PMN) leukocytes. Further, the giant organelles in patient platelets contain acid phosphatase activity. Analytical Electron Microscopy demonstrated that cerium, the capture ion for the acid phosp...
Danna Qian - One of the best experts on this subject based on the ideXlab platform.
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advanced Analytical Electron Microscopy for lithium ion batteries
Npg Asia Materials, 2015Co-Authors: Danna Qian, Karren L More, Ying Shirley Meng, Miaofang ChiAbstract:Recent advances in advanced Analytical Electron Microscopy (AEM) and their implications for studying lithium-ion batteries are reviewed. Lithium-ion batteries are promising for powering electric vehicles and for use in smart grid applications, but require further optimization before they can achieve widespread use in these applications. Powerful advanced AEM techniques are ideal for gaining unprecedented insight into the dynamic processes of active lithium-ion batteries. Miaofang Chi, a research scientist at Oak Ridge National Laboratory, and her co-workers overview recent developments in novel AEM capabilities and demonstrate how such methods have created unrivaled opportunities for understanding the working mechanisms of battery materials. Both static, ex situ studies and newly developed in situ AEM techniques, which offer the opportunity to explore dynamic electrochemical processes during charging and discharging, are highlighted. The scientists also propose future directions.
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interface limited lithium transport in solid state batteries
Journal of Physical Chemistry Letters, 2014Co-Authors: Dhamodaran Santhanagopalan, Danna Qian, Thomas Mcgilvray, Ziying Wang, Feng Wang, Fernando Camino, Jason Graetz, Nancy J Dudney, Ying Shirley MengAbstract:Understanding the role of interfaces is important for improving the performance of all-solid-state lithium ion batteries. To study these interfaces, we present a novel approach for fabrication of electrochemically active nanobatteries using focused ion beams and their characterization by Analytical Electron Microscopy. Morphological changes by scanning transmission Electron Microscopy imaging and correlated elemental concentration changes by Electron energy loss spectroscopy mapping are presented. We provide first evidence of lithium accumulation at the anode/current collector (Si/Cu) and cathode/electrolyte (LixCoO2/LiPON) interfaces, which can be accounted for the irreversible capacity losses. Interdiffusion of elements at the Si/LiPON interface was also witnessed with a distinct contrast layer. These results highlight that the interfaces may limit the lithium transport significantly in solid-state batteries. Fabrication of electrochemically active nanobatteries also enables in situ Electron Microscopy observation of electrochemical phenomena in a variety of solid-state battery chemistries.
Ying Shirley Meng - One of the best experts on this subject based on the ideXlab platform.
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advanced Analytical Electron Microscopy for lithium ion batteries
Npg Asia Materials, 2015Co-Authors: Danna Qian, Karren L More, Ying Shirley Meng, Miaofang ChiAbstract:Recent advances in advanced Analytical Electron Microscopy (AEM) and their implications for studying lithium-ion batteries are reviewed. Lithium-ion batteries are promising for powering electric vehicles and for use in smart grid applications, but require further optimization before they can achieve widespread use in these applications. Powerful advanced AEM techniques are ideal for gaining unprecedented insight into the dynamic processes of active lithium-ion batteries. Miaofang Chi, a research scientist at Oak Ridge National Laboratory, and her co-workers overview recent developments in novel AEM capabilities and demonstrate how such methods have created unrivaled opportunities for understanding the working mechanisms of battery materials. Both static, ex situ studies and newly developed in situ AEM techniques, which offer the opportunity to explore dynamic electrochemical processes during charging and discharging, are highlighted. The scientists also propose future directions.
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interface limited lithium transport in solid state batteries
Journal of Physical Chemistry Letters, 2014Co-Authors: Dhamodaran Santhanagopalan, Danna Qian, Thomas Mcgilvray, Ziying Wang, Feng Wang, Fernando Camino, Jason Graetz, Nancy J Dudney, Ying Shirley MengAbstract:Understanding the role of interfaces is important for improving the performance of all-solid-state lithium ion batteries. To study these interfaces, we present a novel approach for fabrication of electrochemically active nanobatteries using focused ion beams and their characterization by Analytical Electron Microscopy. Morphological changes by scanning transmission Electron Microscopy imaging and correlated elemental concentration changes by Electron energy loss spectroscopy mapping are presented. We provide first evidence of lithium accumulation at the anode/current collector (Si/Cu) and cathode/electrolyte (LixCoO2/LiPON) interfaces, which can be accounted for the irreversible capacity losses. Interdiffusion of elements at the Si/LiPON interface was also witnessed with a distinct contrast layer. These results highlight that the interfaces may limit the lithium transport significantly in solid-state batteries. Fabrication of electrochemically active nanobatteries also enables in situ Electron Microscopy observation of electrochemical phenomena in a variety of solid-state battery chemistries.