Surface Composition and Electrical Conductivity of La2CuO4 and CuO Composite on Exposure to ppm Level H2S.

We investigated the spinning speed dependent surface composition for TE performance with PEDOT:PSS films. The Seebeck coefficient and electrical conductivity of PEDOT:PSS film decrease as the spinning speed elevates. The thicker nanofilm exhibited the best properties in terms of the electrical conductivity and Seebeck coefficient.

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Influence of the surface composition of TiO2 on the electrical conductivity of CuBr–TiO2 composites

Solid State Ionics ◽

10.1016/s0167-2738(01)01034-7 ◽

2002 ◽

Vol 147 (1-2) ◽

pp. 115-121 ◽

Cited By ~ 5

Author(s):

P Knauth

Keyword(s):

Electrical Conductivity ◽

Surface Composition

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Removing Substrate Background in TEM Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052857 ◽

1974 ◽

Vol 32 ◽

pp. 568-569

Author(s):

John C. Russ ◽

Nicholas C. Barbi

Keyword(s):

Electrical Conductivity ◽

Rapid Growth ◽

Organic Film ◽

Absolute Concentration ◽

Background Signal ◽

X Ray ◽

Elemental Concentrations ◽

Transmission Electron ◽

Electron Microscopes ◽

The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

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Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076639 ◽

1983 ◽

Vol 41 ◽

pp. 606-607

Author(s):

Klaus-Ruediger Peters ◽

Samuel A. Green

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Critical Point ◽

Metal Films ◽

High Magnification ◽

Osmium Impregnation ◽

Instrumental Resolution ◽

20 Nm ◽

Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

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Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096813 ◽

1981 ◽

Vol 39 ◽

pp. 16-17

Author(s):

M.P. Thomas ◽

A.R. Waugh ◽

M.J. Southon ◽

Brian Ralph

Keyword(s):

Single Crystals ◽

Photoelectron Spectroscopy ◽

Surface Composition ◽

Depth Profiling ◽

Analytical Techniques ◽

Atom Probe ◽

Probe Field ◽

Preferential Sputtering ◽

Argon Ion Bombardment ◽

Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

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What catalysis needs from the electron microscopist

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105539 ◽

1988 ◽

Vol 46 ◽

pp. 694-695

Author(s):

Alexis T. Bell

Keyword(s):

Active Sites ◽

Heterogeneous Catalysts ◽

Catalyst Deactivation ◽

Surface Composition ◽

Internal Surface ◽

Active Phase ◽

Atomic Scale ◽

Metal Catalyst ◽

Internal Surface Area ◽

Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

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