Twin boundary structure of a Y-Ba-Cu-O superconductor

1989 ◽  
Vol 47 ◽  
pp. 168-169
Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu
Keyword(s):  
Twin Boundary ◽  
Fine Particles ◽  
Imaging Techniques ◽  
Fine Powder ◽  
Orthorhombic Phase ◽  
Boundary Structure ◽  
Crystallographic Axis ◽  
System A ◽  
High Resolution Structure ◽  
Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

Electrical Properties of Dislocations and Boundaries in Semiconductors

1982 ◽  
Vol 14 ◽  
Author(s):  
Hans J. Queisser
Keyword(s):  
Electrical Properties ◽  
Imaging Techniques ◽  
Experimental Methods ◽  
Actual Situation ◽  
Dangling Bond ◽  
Semiconductor Crystals ◽  
Capacitance Spectroscopy ◽  
Electron Microscopes ◽  
Regular Arrays ◽  
Electronic Behavior

ABSTRACTSimple models have been suggested to predict electronic properties of lattice defects in semiconductor crystals: dislocations ought to act via the acceptor character of dangling bonds, and small-angle grain boundaries ought to consist of regular arrays of dislocations. The actual situation in most semiconductors is, however, much more complicated. The observed electrical effects of dislocations do not confirm the dangling-bond concept, they are affected by dissociation and reconstruction. There appear to be differences between straight and kinked dislocations. Dislocations owe much of their electronic behavior to clouds and precipitates of impurities; oxygen in silicon plays a significant role. This review summarizes the present status of experimental methods and results, including luminescence and capacitance spectroscopy as well as mapping and imaging techniques using electron-microscopes.

Non-Equilibrium Reactions of α-Phase PrOx With O2

1992 ◽  
Vol 45 (9) ◽  
pp. 1499 ◽  
Author(s):  
ZC Kang ◽  
J Zhang ◽  
L Eyring
Keyword(s):  
Fine Particles ◽  
Imaging Techniques ◽  
Fluorite Phase ◽  
Praseodymium Oxide ◽  
New Members ◽  
Near Surface ◽  
Α Phase ◽  
Equilibrium Reactions ◽  
Unit Cells ◽  
Pass Through

In this paper we use electron diffraction and high-resolution imaging techniques to study the structural consequences of rapid cooling, to room temperature, of fine particles of praseodymium oxide prepared as the disordered α-phase in the composition range from PrO1.78 to PrO1.83 These experiments reveal that particles of the disordered fluorite phase, prepared at higher temperatures, pass through many steps of order as they cool and oxidize to ordered intermediate structures in their near-surface regions. The entities that bring about this transformation are condensed vacant oxygen sites that segregate on {220} planes and finally order to give members of the even-n homologous series PrnO2n-2. The unit cells for new members of the series with n assumed to be 16 are reported.

scholarly journals FEI Titan 80-300 STEM

2016 ◽  
Vol 2 ◽  
Author(s):  
Marc Heggen ◽  
Martina Luysberg ◽  
Karsten Tillmann
Keyword(s):  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Electron Gun ◽  
Lens System ◽  
Scanning Transmission Electron ◽  
System A ◽  
Transmission Electron ◽  
The World ◽  
Scanning Transmission ◽  
Electron Microscopes

The FEI Titan 80-300 STEM is a scanning transmission electron microscope equipped with a field emission electron gun, a three-condenser lens system, a monochromator unit, and a Cs probe corrector (CEOS), a post-column energy filter system (Gatan Tridiem 865 ER) as well as a Gatan 2k slow scan CCD system. Characterised by a STEM resolution of 80 pm at 300 kV, the instrument was one of the first of a small number of sub-ångström resolution scanning transmission electron microscopes in the world when commissioned in 2006.

scholarly journals Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

2021 ◽  
Vol 13 (24) ◽  
pp. 14071
Author(s):  
Diana Pinto ◽  
Alcindo Neckel ◽  
Guilherme L. Dotto ◽  
Bashir Adelodun
Keyword(s):  
Fine Particles ◽  
Morphological Changes ◽  
Construction Materials ◽  
Waste Recycling ◽  
Particulate Material ◽  
Future Research ◽  
Material Recycling ◽  
Four Seasons ◽  
Electron Microscopes ◽  
Ultra Fine Particles

Building activity is a significant source of atmospheric contamination by ultrafine dust. Cognizant of this fact, those active in the use and recycling of construction materials must be aware of the risks associated with exposure to nanoparticles (NPs) and ultra-fine particles (UFPs), as well as the associated health impacts. This work analyzed NPs and UFPs generated in a small building-material recycling company using high-resolution electron microscopes and X-ray Diffraction. A self-made passive sampler (LSPS) that can obtain particulate samples without physical and morphological changes, especially where there is a suspension of particulate material, was used in this study. A total of 96 particulate samples, using the LSPS for three months in four seasons, were collected during the study. Thus, the dry deposition of the particles, which are considered highly harmful to human health, was found in each of the four seasons of the year. It is suggested that for future research, the toxicological evaluations of the particulates in the construction industry should be investigated through the consideration of measures to control and mitigate the health risks of workers regarding exposure to NPs and UFPs.

scholarly journals Agglomeration of hydrolyzed collagen with blackberry pulp in a fluidized bed

2018 ◽  
Author(s):  
Thayná R Viegas ◽  
Osvaldir Pereira Taranto
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Water Activity ◽  
Fine Particles ◽  
Fine Powder ◽  
Food Ingredient ◽  
Process Yield ◽  
Food Industries ◽  
Hydrolyzed Collagen ◽  
Total Anthocyanins

Hydrolyzed collagen (HC) is a fine powder applied in the pharmaceutical and food industries which has shown good results in the treatment of diseases related to bones, skin and joints. In this  study, HC particles were agglomerated in order to increase particle size, optimizing its use as a food ingredient, its handling and its storage. Agglomeration is a process that not only enlarge the size of fine particles, but also improves its properties, such as instantanization time and flowability. The aim of this work was the agglomeration of HC in a fluidized bed having blackberry pulp as a liquid binder. A full factorial design 22 was used to study the effect of the temperature of the fluidizing air (60, 70, 80ºC) and the flow rate of the liquid binder (0.8, 1.2, 1.6 mL/min) on the process yield, mean particle size, water activity and total anthocyanins content. It was observed that anthocyanins content from the blackberry pulp had higher values with lower temperatures. Water activity had lower values with higher temperatures, but in all conditions, it was lower than 0.6. The enlargement of the granules was observed in all conditions studied, increasing up to 275%. Process yield varied from 67,9 to 80,0%. In all conditions, the instantanization time and flowability improved compared to hydrolyzed collagen before agglomeration.Keywords: hydrolyzed collagen; agglomeration; granulation; fluidized bed; blackberry pulp   

scholarly journals Ghost imaging with electron microscopy inspired, non-orthogonal phase masks

2021 ◽  
Author(s):  
Akhil Kallepalli ◽  
Daan Stellinga ◽  
Ming-Jie Sun ◽  
Richard Bowman ◽  
Enzo Rotunno ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
High Energy ◽  
Reconstruction Method ◽  
Ghost Imaging ◽  
Light Modulator ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Electron Microscopes ◽  
Energy Processes

Abstract Transmission electron microscopes (TEM) achieve high resolution imaging by raster scanning a focused beam of electrons over the sample and measuring the transmission to form an image. While a TEM can achieve a much higher resolution than optical microscopes, they face challenges of damage to samples during the high energy processes involved. Here, we explore the possibility of applying computational ghost imaging techniques adapted from the optical regime to reduce the total, required illumination intensity. The technological lack of the equivalent high-resolution, optical spatial light modulator for electrons means that a different approach needs to be pursued. Using the optical equivalent, we show that a simple six-needle charged device to modulate the illuminating beam, alongside a novel reconstruction method to handle the resulting highly non-orthogonal patterns, is capable of producing images comparable in quality to a raster-scanned approach with much lower peak intensity.

scholarly journals ESTIMATION OF CURCUMINOIDS IN CURCUMA KARNATAKENSIS (WHITE TURMERIC) - AN ENDEMIC TAXON

2017 ◽  
Vol 10 (10) ◽  
pp. 360 ◽  
Author(s):  
Tejavathi Dh ◽  
Sujatha Bs ◽  
Kannan R
Keyword(s):  
High Performance ◽  
Fine Powder ◽  
Selected Reaction Monitoring ◽  
Liquid Chromatography Mass Spectrometry ◽  
Metabolite Analysis ◽  
Pharmacological Activities ◽  
System A ◽  
Two Samples ◽  
Endemic Taxon ◽  
First Time

  Objective: To estimate the contents of curcuminoids in two samples of Curcuma karnatakensis collected from different localities.Methods: Quantification of curcuminoids was estimated by ultra-high performance liquid chromatography-mass spectrometry/selected reaction monitoring (UHPLC-MS/SRM) method in two samples of C. karnatakensis for the first time. Fine powder of rhizomatous rootstocks of two plant samples collected from different habitats were served as Samples A and B. The MS used for the metabolite analysis is a Vantage TSQ triple stage quadrupole MS equipped with heated electrospray ionization. The MS is coupled with an Agilent 1290 infinity UHPLC system. A stock solution of curcuminoid standard was prepared by dissolving 5 mg of standard in 1 mL of methanol. Seven different concentrations of standard (0.15-10 ng on column) were injected for the UHPLC-MS/SRM analysis. Separations were performed using a C-18 column with a flow rate of 0.2 mL/minute.Results: Contents of curcumin, demethoxycurcumin, and bisdemethoxycurcumin were found to be varied in two samples and lowest than any other species of Curcuma studied. Variation in the contents may be due to their different habitats in which they are growing.Conclusion: The present attempt of analyzing the contents of curcuminoids in this endemic taxon for the first time will provide the basis for further pharmacological analysis to authenticate the efficacy of these active principles as the curcuminoids are known for varied pharmacological activities.

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