Rotating Machinery, Optical Methods & Scanning LDV Methods, Volume 6

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Download Full-text

Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174382 ◽

1990 ◽

Vol 48 (4) ◽

pp. 250-251

Author(s):

H. Seiler ◽

U. Haas ◽

K.H. Körtje

Keyword(s):

Bulk Material ◽

High Vacuum ◽

Optical Methods ◽

Metal Particles ◽

Silver Particles ◽

Low Loss ◽

Plasmon Excitation ◽

First Results ◽

Diffraction Patterns ◽

Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

Download Full-text

Optical Methods of Engineering Analysis

10.1017/cbo9780511575013 ◽

1995 ◽

Cited By ~ 146

Author(s):

Gary Cloud

Keyword(s):

Optical Methods ◽

Engineering Analysis

Download Full-text

Comparison of sensitivity of the refractometric methods of frustrated total internal reflection and surface plasmon resonance

Izmeritel`naya Tekhnika ◽

10.32446/0369-1025it.2020-2-44-49 ◽

2020 ◽

pp. 44-49

Author(s):

I. N. Pavlov

Keyword(s):

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Total Internal Reflection ◽

Resonance Method ◽

Internal Reflection ◽

Optical Methods ◽

Thin Boundary Layer ◽

Experimental Conditions ◽

Frustrated Total Internal Reflection

Two optical methods, namely surface plasmon resonance imaging and frustrated total internal reflection, are described in the paper in terms of comparing their sensitivity to change of refractive index of a thin boundary layer of an investigated medium. It is shown that, despite the fact that the theoretically calculated sensitivity is higher for the frustrated total internal reflection method, and the fact that usually in practice the surface plasmon resonance method, on the contrary, is considered more sensitive, under the same experimental conditions both methods show a similar result.

Download Full-text