scholarly journals Polar Eolian Sand Transport: Grain Characteristics Determined by an Automated Scanning Electron Microscope (QEMSCAN®)

2008 ◽  
Vol 40 (4) ◽  
pp. 731-743 ◽  
Author(s):  
Johanna C. Speirs ◽  
Hamish A. McGowan ◽  
David T. Neil
Author(s):  
S. Pignolet-Brandom ◽  
K. J. Reid

QEM*SEM, or quantitative evaluation of materials by scanning electron microscopy, is a fully automated scanning electron microscope system that was designed and engineered by CSIRO in Australia for applications to the minerals industry. It is an integrated system in which the computer and its associated hardware and software control SEM operations. Minerals can be identified in point, linear or area scans. Depending on the type of scan, information is extracted from the data files and summarized in tables and graphs covering mineral abudances, associations, sizes, free surface area and the degree of liberation. In addition, area scans can be replayed on a graphics monitor to produce QEM*SEM mineral species maps.The QEM*SEM system consists of an International Scientific Instruments SX-40 scanning electron microscope with a specially designed sample chamber that permits 100 mm movement of the stage. The EDS units were designed for rapid collection of x-ray spectra and consist of four lithium drifted silicon detectors each with a separate preamplifier.


Author(s):  
R. E. Ferrell ◽  
G. G. Paulson

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.


Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.


Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.


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