The Characterization of Coal Structures for Coal Gasification Reactions Using Tem/Stem Techniques

The liquefaction and gasification of various coals are increasingly important technological utilizations of coal which are dependent upon its physical characteristics as well as its chemistry. In this respect, both the size and distribution of pores and the size, distribution and chemical identity of the submicron size minerals are physical parameters of great interest because of their probable influence in the coal conversion processes. In Berkeley, this study is proceeding by examination of such processes using an environmental cell in a high voltage microscope, by which the influence of different gases, temperatures and pressure upon the gasification reaction can be studied. An important first step in such a study is the primary characterization of the coals to be studied and the combined use of both transmission (TEM) and scanning transmission electron microscope (STEM) analyses utilizing both convergent beam methods and an energy dispersive X-ray analytical detector is thus a powerful tool in such a characterization.

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Measurement of lattice parameter at the nanometer scale using convergent-beam microdiffraction from a thermal emission source

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149283 ◽

1993 ◽

Vol 51 ◽

pp. 690-691

Author(s):

W. T. Pike

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Thermal Emission ◽

Lattice Parameter ◽

Scanning Transmission Electron Microscope ◽

Emission Source ◽

Device Structure ◽

Transmission Electron ◽

Scanning Transmission ◽

Convergent Beam

With the advent of crystal growth techniques which enable device structure control at the atomic level has arrived a need to determine the crystal structure at a commensurate scale. In particular, in epitaxial lattice mismatched multilayers, it is of prime importance to know the lattice parameter, and hence strain, in individual layers in order to explain the novel electronic behavior of such structures. In this work higher order Laue zone (holz) lines in the convergent beam microdiffraction patterns from a thermal emission transmission electron microscope (TEM) have been used to measure lattice parameters to an accuracy of a few parts in a thousand from nanometer areas of material.Although the use of CBM to measure strain using a dedicated field emission scanning transmission electron microscope has already been demonstrated, the recording of the diffraction pattern at the required resolution involves specialized instrumentation. In this work, a Topcon 002B TEM with a thermal emission source with condenser-objective (CO) electron optics is used.

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Detailed Calculations of Thermal Diffuse Scattering

Microscopy and Microanalysis ◽

10.1017/s1431927600012654 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 1153-1154

Author(s):

D.A. Müller ◽

B. Edwards ◽

E.J. Kirkland ◽

J. Silcox

Keyword(s):

Diffuse Scattering ◽

Single Point ◽

Scanning Transmission Electron Microscope ◽

Diffraction Spot ◽

Thermal Diffuse Scattering ◽

Transmission Electron ◽

Einstein Model ◽

Scanning Transmission ◽

Convergent Beam ◽

Thermal Diffuse

Convergent beam electron diffraction (CBED) produces a diffraction pattern from a single point on the specimen using a focused probe in the scanning transmission electron microscope (STEM). Because the incident wavefunction is a focused probe, each diffraction spot is enlarged to a disk the size of the objective aperture. Thermal vibration in the specimen reduces the intensity of the diffraction disks and introduces scattering in between the disk. This normally forbidden scattering between the diffraction disks is referred to as thermal diffuse scattering (TDS). The effects are most pronounced at large scattering angles, where TDS scattering can greatly reduce the intensity of the higher order Laue zone (HOLZ) lines. Previous work on modeling the TDS intensity involved the so-called frozen phonon method and the Einstein model of lattice vibration. The Einstein model assumes that each atom in the specimen vibrates independently of every other atom in the specimen and possible correlations among adjacent atoms are ignored.

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Microstructural and Compositional Characterization of SiC-On-Insulator Structures

Microscopy and Microanalysis ◽

10.1017/s1431927600017177 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 770-771

Author(s):

Manabu Ishimaru ◽

Robert M. Dickerson ◽

Kurt E. Sickafus

Keyword(s):

Ion Implantation ◽

Integrated Circuit ◽

High Speed ◽

Scanning Transmission Electron Microscope ◽

Oxygen Ions ◽

Oxygen Ion ◽

Transmission Electron ◽

Scanning Transmission ◽

Oxygen Ion Implantation

As the size of Si integrated circuit structures is continually reduced, interest in semiconductor-oninsulator (SOI) structures has heightened. SOI structures have already been developed for Si using oxygen ion implantation. However, the application of Si devices is limited due to the physical properties of Si. As an alternative to Si, SiC is a potentially important semiconductor for high-power, high-speed, and high-temperature electronic devices. Therefore, this material is a candidate for expanding the capabilities of Si-based technology. In this study, we performed oxygen ion implantation into bulk SiC to produce SiC-on-insulator structures. We examined the microstructures and compositional distributions in implanted specimens using transmission electron microscopy and a scanning transmission electron microscope equipped with an energy-dispersive X-ray spectrometer (STEM-EDX).Figures 1(a) and 2(a) show bright-field images of 6H-SiC implanted with 180 keV oxygen ions at 650 °C to fluences of 7xl017 and 1.4xl018 cm−2, respectively. Three regions with distinct image contrast are apparent in Figs. 1(a) and 2(a), as indicated by A, B, and C.

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Incoherent High-Resolution Z-Contrast Imaging of Silicon and Gallium Arsenide Using HAADF-STEM

MRS Proceedings ◽

10.1557/proc-589-185 ◽

1999 ◽

Vol 589 ◽

Author(s):

Y Kotaka ◽

T. Yamazaki ◽

Y Kikuchi ◽

K. Watanabe

Keyword(s):

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Contrast Imaging ◽

High Spatial Resolution Image ◽

Transmission Electron ◽

Eigen Value ◽

Scanning Transmission ◽

Annular Dark Field ◽

Convergent Beam ◽

Z Contrast

AbstractThe high-angle annular dark-field (HAADF) technique in a dedicated scanning transmission electron microscope (STEM) provides strong compositional sensitivity dependent on atomic number (Z-contrast image). Furthermore, a high spatial resolution image is comparable to that of conventional coherent imaging (HRTEM). However, it is difficult to obtain a clear atomic structure HAADF image using a hybrid TEM/STEM. In this work, HAADF images were obtained with a JEOL JEM-2010F (with a thermal-Schottky field-emission) gun in probe-forming mode at 200 kV. We performed experiments using Si and GaAs in the [110] orientation. The electron-optical conditions were optimized. As a result, the dumbbell structure was observed in an image of [110] Si. Intensity profiles for GaAs along [001] showed differences for the two atomic sites. The experimental images were analyzed and compared with the calculated atomic positions and intensities obtained from Bethe's eigen-value method, which was modified to simulate HAADF-STEM based on Allen and Rossouw's method for convergent-beam electron diffraction (CBED). The experimental results showed a good agreement with the simulation results.

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Visualization of ferroaxial domains in an order-disorder type ferroaxial crystal

Nature Communications ◽

10.1038/s41467-020-18408-6 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 2

Author(s):

T. Hayashida ◽

Y. Uemura ◽

K. Kimura ◽

S. Matsuoka ◽

D. Morikawa ◽

...

Keyword(s):

Optical Rotation ◽

Axial Vector ◽

Difference Image ◽

Image Sensing ◽

Transmission Electron ◽

Combined Use ◽

Scanning Transmission ◽

Ferroic Materials ◽

Convergent Beam ◽

Disorder Type

Abstract Ferroaxial materials that exhibit spontaneous ordering of a rotational structural distortion with an axial vector symmetry have gained growing interest, motivated by recent extensive studies on ferroic materials. As in conventional ferroics (e.g., ferroelectrics and ferromagnetics), domain states will be present in the ferroaxial materials. However, the observation of ferroaxial domains is non-trivial due to the nature of the order parameter, which is invariant under both time-reversal and space-inversion operations. Here we propose that NiTiO3 is an order-disorder type ferroaxial material, and spatially resolve its ferroaxial domains by using linear electrogyration effect: optical rotation in proportion to an applied electric field. To detect small signals of electrogyration (order of 10−5 deg V−1), we adopt a recently developed difference image-sensing technique. Furthermore, the ferroaxial domains are confirmed on nano-scale spatial resolution with a combined use of scanning transmission electron microscopy and convergent-beam electron diffraction. Our success of the domain visualization will promote the study of ferroaxial materials as a new ferroic state of matter.

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La-Based Perovskites as Oxygen-Exchange Redox Materials for Solar Syngas Production

MRS Advances ◽

10.1557/adv.2017.300 ◽

2017 ◽

Vol 2 (55) ◽

pp. 3365-3370 ◽

Cited By ~ 16

Author(s):

Rahul R. Bhosale ◽

Anand Kumar ◽

Anchu Ashok ◽

Parag Sutar ◽

Gorakshnath Takalkar ◽

...

Keyword(s):

Solution Combustion Synthesis ◽

Scanning Transmission Electron Microscope ◽

Bet Surface Area ◽

Synthesis And Characterization ◽

Solution Combustion ◽

Syngas Production ◽

Transmission Electron ◽

Scanning Transmission ◽

Synthesis Approach

ABSTRACTThis contribution reports the synthesis and characterization of La-based perovskites which can be used for the production of syngas via solar thermochemical splitting of H2O/CO2. The La-based perovskites were synthesized using a solution combustion synthesis approach. The derived perovskites were analyzed using powder X-ray diffractometer (PXRD), BET surface area analyzer (BET), and scanning/transmission electron microscope (SEM/TEM). The results associated with the synthesis and characterization of La-based perovskites is reported in detail.

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Elaboration and characterization of novel polyamide-12-layered titanoniobates nanocomposites

Journal of Materials Research ◽

10.1557/jmr.2009.0410 ◽

2009 ◽

Vol 24 (11) ◽

pp. 3358-3371 ◽

Cited By ~ 2

Author(s):

Sophie Chausson ◽

Richard Retoux ◽

Jean-Michel Rueff ◽

Loïc LE Pluart ◽

Pierre-Jean Madec ◽

...

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Scanning Transmission Electron Microscope ◽

Thermomechanical Properties ◽

Polyamide 12 ◽

Transmission Electron ◽

Scanning Transmission ◽

Before And After ◽

Basic Reaction

This article describes the synthesis and the characterization of a polyamide-12 filled with a nanostructured organic/inorganic titanoniobate hybrid material. The pristine oxide KTiNbO5 has been successfully organomodified by N-alkyl amines via an acido-basic reaction after a cationic exchange step as shown by x-ray diffraction. Transmission electron microscope study and scanning transmission electron microscope observations have been used to describe the change of morphology of the nanofillers before and after processing; the micronic aggregates were changed into single sheets and dispersed in the polymer. Thermomechanical properties of the composites have been determined, and their analyses with structure-properties models are consistent with the exfoliation of the organomodified titanoniobates.

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Characterization of Sc2O3&CeO2-Stabilized ZrO2 Powders Via Co-Precipitation or Hydrothermal Synthesis

Microscopy and Microanalysis ◽

10.1017/s1431927613012270 ◽

2013 ◽

Vol 19 (S5) ◽

pp. 29-32 ◽

Cited By ~ 4

Author(s):

Justyna Grzonka ◽

Victor Vereshchak ◽

Oleksiy Shevchenko ◽

Oleksandr Vasylyev ◽

Krzysztof J. Kurzydłowski

Keyword(s):

High Temperature ◽

Hydrothermal Synthesis ◽

Hydrothermal Reaction ◽

Scanning Transmission Electron Microscope ◽

Cubic Phase ◽

Precipitation Technique ◽

Transmission Electron ◽

Scanning Transmission ◽

Co Precipitation

AbstractAs the presence of Sc2O3 and CeO2 is known to largely enhance the ionic conductivity in the temperature range of 600–800°C, compared with the conventional yttria-stabilized ZrO2, Sc2O3&CeO2-stabilized ZrO2 provide its applicability as electrolytes in solid oxide fuel cells. The current study introduces the methodology to synthesize Sc2O3&CeO2-stabilized ZrO2 powders by using co-precipitation technique or high-temperature hydrothermal reaction, and further describes the structural characterization of the zirconia powders synthesized by the above-mentioned two methods. The co-precipitation technique was found to allow obtaining powders of cubic phase, whereas high-temperature hydrothermal synthesis results in the presence of a monoclinic phase as well. The scanning transmission electron microscope observations also confirm that the size of the synthesized ZrO2 powders in this study is found to be much smaller than that of commercially available powders.

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