Comparison of methods employed to extract information contained in seafloor backscatter

Coherent electron nanodiffraction from clean silver nano particles in a UHV STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015112x ◽

1993 ◽

Vol 51 ◽

pp. 1058-1059

Author(s):

J. Liu ◽

M. Pan ◽

G. E. Spinnler

Keyword(s):

Supported Catalysts ◽

Imaging Techniques ◽

Nano Particles ◽

Metal Particles ◽

Shape Structure ◽

Dynamical Simulations ◽

Small Metal Particles ◽

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Small metal particles have peculiar chemical and physical properties as compared to bulk materials. They are especially important in catalysis since metal particles are common constituents of supported catalysts. The structural characterization of small particles is of primary importance for the understanding of structure-catalytic activity relationships. The shape and size of metal particles larger than approximately 5 nm in diameter can be determined by several imaging techniques. It is difficult, however, to deduce the shape of smaller metal particles. Coherent electron nanodiffraction (CEND) patterns from nano particles contain information about the particle size, shape, structure and defects etc. As part of an on-going program of STEM characterization of supported catalysts we report some preliminary results of CEND study of Ag nano particles, deposited in situ in a UHV STEM instrument, and compare the experimental results with full dynamical simulations in order to extract information about the shape of Ag nano particles.

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The Contribution of Phonon-Scattered Electrons to High-Resolution Electron Micrographs of Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179063 ◽

1990 ◽

Vol 48 (1) ◽

pp. 62-63

Author(s):

H. Kohl

Keyword(s):

High Resolution ◽

Spherical Aberration ◽

High Resolution Electron Microscopy ◽

Static Potential ◽

Qualitative Comparison ◽

The Past ◽

Resolution Electron ◽

High Resolution Images ◽

High Resolution Electron Micrographs ◽

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High-Resolution Electron Microscopy is able to determine structures of crystals and interfaces with a spatial resolution of somewhat less than 2 Å. As the image is strongly dependent on instrumental parameters, notably the defocus and the spherical aberration, the interpretation of micrographs necessitates a comparison with calculated images. Whereas one has often been content with a qualitative comparison of theory with experiment in the past, one is currently striving for quantitative procedures to extract information from the images [1,2]. For the calculations one starts by assuming a static potential, thus neglecting inelastic scattering processes.We shall confine the discussion to periodic specimens. All electrons, which have only been elastically scattered, are confined to very few directions, the Bragg spots. In-elastically scattered electrons, however, can be found in any direction. Therefore the influence of inelastic processes on the elastically (= Bragg) scattered electrons can be described as an attenuation [3]. For the calculation of high-resolution images this procedure would be correct only if we had an imaging energy filter capable of removing all phonon-scattered electrons. This is not realizable in practice. We are therefore forced to include the contribution of the phonon-scattered electrons.

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A comparison of methods for reducing stress among dental students

Journal of Dental Education ◽

10.1002/j.0022-0337.1986.50.9.tb02039.x ◽

1986 ◽

Vol 50 (9) ◽

pp. 542-544 ◽

Cited By ~ 2

Author(s):

CE Howard ◽

LE Graham ◽

SJ Wycoff

Keyword(s):

Dental Students ◽

Comparison Of Methods ◽

Reducing Stress

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The Use of Real-Time Visual Displays of Speech in the Training of a Profoundly Deaf, Nonspeaking Child: A Case Report

Journal of Speech and Hearing Disorders ◽

10.1044/jshd.3603.397 ◽

1971 ◽

Vol 36 (3) ◽

pp. 397-409 ◽

Cited By ~ 10

Author(s):

Rachel E. Stark

Keyword(s):

Case Report ◽

Real Time ◽

Speech Production ◽

Behavior Problem ◽

Deaf Children ◽

Developmental Sequence ◽

Visual Displays ◽

Individual Instruction ◽

Academic Record ◽

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Real-time amplitude contour and spectral displays were used in teaching speech production skills to a profoundly deaf, nonspeaking boy. This child had a visual attention problem, a behavior problem, and a poor academic record. In individual instruction, he was first taught to produce features of speech, for example, friction, nasal, and stop, which are present in vocalizations of 6- to 9-month-old infants, and then to combine these features in syllables and words. He made progress in speech, although sign language and finger spelling were taught at the same time. Speech production skills were retained after instruction was terminated. The results suggest that deaf children are able to extract information about the features of speech from visual displays, and that a developmental sequence should be followed as far as possible in teaching speech production skills to them.

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