Atomic Force and Electron Microscopic Investigations of Lead Selenide Crystals Grown under Monolayers

Author(s):  
Janos H. Fendler ◽  
Jianping Yang
1994 ◽  
Vol 27 (5) ◽  
pp. 402-411 ◽  
Author(s):  
J. Yang ◽  
J. H. Fendler ◽  
T.-C. Jao ◽  
T. Laurion

Author(s):  
G. Lehmpfuhl

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.


Author(s):  
Dr. G. Kaemof

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.


1977 ◽  
Vol 55 (20) ◽  
pp. 2565-2573 ◽  
Author(s):  
Robert D. Slocum ◽  
Gary L. Floyd

The nature of the association between the basidiomycetous mycobiont and the blue-green phycobiont in two species of the tropical basidiolichen Dictyonema was investigated using Nomarski light optics and scanning and transmission electron microscopy. Although members of this family may exhibit either a homoiomerous or heteromerous type of thallus organization, the fungus–alga relationship at the cellular level is remarkably consistent. Scytonema filaments are intimately associated with appressorial hyphae of the mycobiont and with extensive intracellular hyphae, which appear to be unrelated to the basidiomycetous fungal symbiont. This is the first report of a lichen displaying an apparent dual fungal symbiosis with the algal host. Association with the intracellular fungus produces no discernible damage to the phycobiont and apparently does not interfere with the symbiosis involving the basidiomycetous fungus.


Author(s):  
V.S. Zayonchkovsky ◽  
Aung Kyaw Kyaw ◽  
A.V. Andreev

Films containing layers of dispersion-hardening alloys (LDHA) based on the Fe-Cr-Co system were obtained by magnetron sputtering. LDHA acquire the properties of film permanent magnets after a single-stage «fast» high-vacuum annealing. Bulk materials acquire such properties only after many hours of multi-stage heat treatment. The film samples acquire these properties in tens of seconds. The morphology of their surface was studied to determine the origin of the coercive force of film samples. The surface morphology was studied using high resolution scanning electron microscopy and atomic force microscopy. We studied two compositions that, in bulk, have a different tendency to form many phases during crystallization. In magnetron sputtering, the alloy in which a multiphase state is easily formed is polycrystalline. The antipode alloy in magnetron sputtering is realized in an amorphous state. After annealing, both alloys are in a polycrystalline state. Electron microscopic examination showed that as a result of annealing, crystallites are formed with a large projection onto the substrate plane, which grow due to the nearest neighbors. Moreover, these crystallites have not only a large area, but also a height. After annealing, both alloys are in a polycrystalline state. Electron microscopic examination showed that as a result of annealing, crystallites are formed with a large projection onto the substrate plane, which grow due to the nearest neighbors. Moreover, these crystallites have not only a large area, but also a height. What is determined by atomic force microscopy. High crystallites are also faceted. This may indicate that the composition of these crystallites differs from the composition of the surrounding layer, which may be the reason for the increase in coercive force as a result of annealing.


2005 ◽  
Vol 38 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Leonore Wiehl ◽  
Jens Oster ◽  
Michael Huth

Epitaxially grown Mo films on a faceted corundum (α-Al2O3)mplane were investigated by transmission electron microscopy. Low- and high-resolution images were taken from a cross-section specimen cut perpendicular to the facets. It was possible to identify unambiguously the crystallographic orientation of these facets and explain the considerable deviation (∼10°) of the experimental interfacet angle, as measured with atomic force microscopy (AFM), from the expected value. For the first time, proof is given for a smooth \{10\bar{1}1\} facet and a curvy facet with orientation near to \{10\bar{1}\bar{2}\}. Moreover, the three-dimensional epitaxial relationship of an Mo film on a faceted corundummsurface was determined.


1984 ◽  
Vol 23 (6) ◽  
pp. 482-485
Author(s):  
T. I. Fil' ◽  
Yu. I. Khimchenko ◽  
O. A. Katsyuk ◽  
A. K. Dudchenko

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