Scanning Electron Microscopy, X-Ray Microanalysis, and Analytical Electron Microscopy

The knowledge about the occurrence of gold is essential both to the explanation for the genesis of gold mineralization in its deposits and to the evaluation and exploration or even smelt process of its ores. It has been well known that the gold occurrence in the Carlin-type ores still remains a difficult question to be answered because of the tiny scale of its locality and its very low content.This paper reports the results of our analysis on some gold bearing minerals in the Carlin-type ores discovered during recent years in China with combined use of analytical electron microscopy (AEM), scanning electron microscopy-energy dispersive X ray spectrometry (SEM-EDX) and synchrotron X ray flourescence analysis (SXRF) techniques as following:(1) Some gold occurred as submicron size grains in the ores (see Photo 1-4 and Figure 1-3) with grain size generally less than 0.2 micron.(2) It has been found by AEM and SEM-EDX observation and SXRF analysis that gold occurred as micrograins embedded in the boundaries of clay or quartz minerals rather than, as said, entered the lattice or adhered as a covering film to the surface of clay minerals (see Figure 4).

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The characterization of rapidly solidified Al-8Fe-2Mo powder

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144206 ◽

1986 ◽

Vol 44 ◽

pp. 546-547

Author(s):

H.K. Plummer ◽

W.T. Donlon ◽

J.E. Allison ◽

S. Shinozaki

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Light Microscopy ◽

Analytical Electron Microscopy ◽

Powder Sample ◽

Two Component ◽

Analytical Electron ◽

Rapidly Solidified ◽

Scanning Electron

A centrifugally atomized rapidly solidified Al-8Fe-2Mo powder was characterized by Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Analytical Electron Microscopy (AEM). The powder sample was studied in an as-solidified state and after annealing in 1 at. argon for 6 hr at 400°C. Further studies have characterized the consolidated bars produced by compaction and extrusion of these powders.The 30 to 150 μm powders are spherical as seen in the SEM (Fig.1) with small (5 to 15 μm) satellite powders sometimes attached in external (A,B Fig.1) and internal (A Fig.2C) locations. A comparison of powders (epoxy mounted and polished) by both the LM (Fig. 2A) and the SEM (Figs. 2B and 2C) reveals a two component microstructure with occasional voids.

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Overcoming Severe XEDS Peak Overlaps with the AEM

Microscopy Today ◽

10.1017/s1551929500055346 ◽

2006 ◽

Vol 14 (2) ◽

pp. 34-37

Author(s):

Scott D. Walck

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Electron Microscope ◽

Energy Dispersive Spectroscopy ◽

Analytical Techniques ◽

Maximum Energy ◽

X Ray ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Scanning Electron

Of all the analytical techniques in electron microscopy, X-ray energy dispersive spectroscopy (XEDS) is perhaps the most useful. It provides a quick identification of the elements and even with semiquantitative methods; a reasonable composition can be obtained. However, in the scanning electron microscopy (SEM), there are materials systems in which severe peak overlaps of heavier elements L and M lines cannot be easily deconvolved with lighter elements' K lines. In addition, without a sufficient overvoltage in the SEM, even identification of the heavier elements can be difficult. In the analytical electron microscope (AEM), there is always sufficient overvoltage to excite all of the elements' K-lines. However, all of the K-lines might not be able to be detected with commercially available instruments. This is illustrated in Fig.l where the maximum energy of the detector system might be set to 10, 20, or 40 keV.

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Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053590 ◽

1982 ◽

Vol 40 ◽

pp. 186-187

Author(s):

R.G. Frederickson ◽

R.G. Ulrich ◽

J.L. Culberson

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Experimental Epilepsy ◽

Metallic Cobalt ◽

Experimental Animals ◽

X Ray ◽

Brain Surface ◽

Meningeal Cells ◽

Analytical Electron ◽

The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

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Identification of calcium oxalate crystals in dried or fixed tobacco leaf

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111550 ◽

1984 ◽

Vol 42 ◽

pp. 288-289

Author(s):

Vicki L. Baliga ◽

Mary Ellen Counts

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Calcium Oxalate ◽

Growth And Development ◽

Polarized Light ◽

Calcium Oxalate Crystals ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

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Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090877 ◽

1976 ◽

Vol 34 ◽

pp. 178-179

Author(s):

M. L. Zimny ◽

A. C. Haller

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Body Temperature ◽

Ground Squirrel ◽

Alveolar Bone ◽

X Ray ◽

Dental Tissues ◽

Bone Minerals ◽

Apical Tooth ◽

Scanning Electron

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.

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Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139834 ◽

1995 ◽

Vol 53 ◽

pp. 692-693

Author(s):

Yun Lu ◽

David C. Joy

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Morphological Development ◽

Early Hydration ◽

X Ray ◽

Blended Cements ◽

Powder Particles ◽

Chemical Wastes ◽

Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

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Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119806 ◽

1985 ◽

Vol 43 ◽

pp. 610-613

Author(s):

M.G. Baldini ◽

S. Morinaga ◽

D. Minasian ◽

R. Feder ◽

D. Sayre ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Cell Biology ◽

Imaging Technique ◽

Human Platelets ◽

X Rays ◽

X Ray ◽

X Ray Imaging ◽

Complex Phenomena ◽

Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

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