scholarly journals SEM/EDS observations of impurities in polar ice: artifacts or not?

2003 ◽  
Vol 49 (165) ◽  
pp. 184-190 ◽  
Author(s):  
Ian Baker ◽  
Daniel Cullen
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Specimen Preparation ◽  
Polar Ice ◽  
Series Of Experiments ◽  
Scanning Electron

AbstractA series of experiments was undertaken to determine the origin of filaments found in grain boundaries and impurity spots found in grain interiors of polar ice during observation in the scanning electron microscope. It is shown that although the filaments are artifacts, they demonstrate the presence of impurities segregated to the grain boundary planes. It is also demonstrated that the impurities observed in the grain interior reside there and were not transported from the grain boundaries during specimen preparation or observation.

Comparison of freeze-fractured yeast replicas using conventional TEM and low-voltage field-emission SEM

1989 ◽  
Vol 47 ◽  
pp. 74-75
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Terrence W. Reilly
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Lens System ◽  
Air Drying ◽  
Preparation Techniques ◽  
Scanning Electron

Although the first commercial scanning electron microscope (SEM) was introduced in 1965, the limited resolution and the lack of preparation techniques initially confined biological observations to relatively low magnification images showing anatomical surface features of samples that withstood the artifacts associated with air drying. As the design of instrumentation improved and the techniques for specimen preparation developed, the SEM allowed biologists to gain additional insights not only on the external features of samples but on the internal structure of tissues as well. By 1985, the resolution of the conventional SEM had reached 3 - 5 nm; however most biological samples still required a conductive coating of 20 - 30 nm that prevented investigators from approaching the level of information that was available with various TEM techniques. Recently, a new SEM design combined a condenser-objective lens system with a field emission electron source.

A Biological Cryosystem for the Scanning Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 414-415
Author(s):  
Zhang zhaohua ◽  
Luo Dong ◽  
Guo Yisong
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Natural State ◽  
Specimen Preparation ◽  
Cold Stage ◽  
Specimen Temperature ◽  
Successful Design ◽  
Scanning Electron

Since early 1970's the use of cold stage on SEM for observation of hydrated samples in their natural state has become more and more popular despite its high cost. Experiences gained from earlier experiments indicate that a successful design should incorporate thefollowing features:1. The specimen temperature should be below −135°C (the recrystallization point of water), lower the temperature, better the results.2. The frozen specimen, the cold block in the specimen preparation chamber, as well as the cold stage should be kept under vacuum at all times to keep them frost free.3. Different specimen preparation processes such as fracturing, coating and sublimation should be possible in one compact preparation chamber .

A technique for the examination of polar ice using the scanning electron microscope

2002 ◽  
Vol 205 (2) ◽  
pp. 118-124 ◽  
Author(s):  
P. R. F. Barnes ◽  
R. Mulvaney ◽  
E. W. Wolff ◽  
K. Robinson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polar Ice ◽  
Scanning Electron

Segregation and Precipitation Behavior of Phosphorus in a Ni-Fe-Cr Base Wrought Superalloy

2018 ◽  
Vol 913 ◽  
pp. 150-156 ◽  
Author(s):  
Sha Zhang ◽  
An Wen Zhang ◽  
Wei Yang Wang ◽  
Xin Xin ◽  
Kai Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Grain Boundaries ◽  
Energy Dispersive Spectroscopy ◽  
Peak Temperature ◽  
Energy Dispersive ◽  
Precipitation Behavior ◽  
Temperature Range ◽  
Precipitation Temperature ◽  
Scanning Electron

The segregation and precipitation behavior of phosphoruswas studied in aNi-Fe-Cr base wroughtsuperalloy. The precipitation behavior of phosphides in the alloy contained 0.025% Pwas examined after soaking at 750-1080°C to determine the precipitation temperature range of MNP-type phosphide. The microstructuresunder these various conditions wereinvestigated by scanning electron microscope(SEM) and energy dispersive spectroscopy (EDS). The precipitation temperature of the phosphide in the alloy was determined to be in the range of 850-1040 °C and the precipitation peak temperature was around 980°C.In addition, the melting temperatureof the phosphide was determined to be between 1200 °C and 1250 °C. The current results indicate the tendency of phosphorus segregated at grain boundaries.

Microdiffraction phase identification in the scanning electron microscope (SEM)

2004 ◽  
Vol 19 (2) ◽  
pp. 100-103 ◽  
Author(s):  
R. P. Goehner ◽  
J. R. Michael
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Beam Current ◽  
Electron Diffraction Data ◽  
Specimen Preparation ◽  
Phase Identification ◽  
Electron Backscattered Diffraction ◽  
Backscattered Electron ◽  
Ccd Detectors ◽  
Scanning Electron

The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the microstructure of the specimen. With the development of charge coupled device (CCD)-based detectors, backscattered electron Kikuchi patterns, alternately referred to as electron backscattered diffraction (EBSD) patterns, can be easily collected. Previously, EBSD has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical EBSD can now be acquired from a micron or submicron sized crystal using an exposure time of 1–10 s with an accelerating voltage of 10–40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using EBSD is unique in that the properly equipped SEM permits high magnification images, EBSDs, and elemental information to be collected from bulk specimens. EBSD in the SEM has numerous advantages over other electron beam-based crystallographic techniques. The large angular view (∼70°) provided by EBSD and the ease of specimen preparation are distinct advantages of the technique. No sample preparation beyond what is commonly used for SEM specimens is required for EBSD.

Creep in Polycrystalline Aluminum

1999 ◽  
Vol 586 ◽  
Author(s):  
C. L. Briant ◽  
D. L. Davidson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Grain Boundary ◽  
Triple Point ◽  
Tensile Strain ◽  
Boundary Migration ◽  
Local Strain ◽  
Grain Boundary Migration ◽  
Polycrystalline Aluminum ◽  
Scanning Electron

ABSTRACTThis paper presents a study of creep in polycrystalline aluminum. The sample was deformed in a scanning electron microscope and local strain was measured by analyzing micrographs taken during the test. EBSP was used to examine grain curvature and recrystallization The results showed that tensile strain developed during the test. The strain was not constant but varied both spatially and with time. Significant grain boundary migration occurred during the test, and near a triple point a grain with a completely new orientation was formed.

scholarly journals A Review Of The Development Of Scanning Electron Microscopy At High Chamber Pressure

1997 ◽  
Vol 5 (1) ◽  
pp. 14-15
Author(s):  
Vivian Robinson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chamber Pressure ◽  
Natural State ◽  
Specimen Preparation ◽  
Electron Microscopes ◽  
Reproducible Manner ◽  
Scanning Electron

Ever since electron microscopes were developed, it has been the goal of microscopists to observe specimens in their natural state, free from artefacts which can often be introduced through specimen preparation. For most biological specimens, that includes the presence of water. With a pressure of 10-4 torr or lower required to operate a scanning electron microscope (SEM), liquid water, which required a pressure of above 5 torr, was clearly a problem.Although several attempts had been made to examine hydrated specimens in a SEM, the first published results of water imaged in a stable and reproducible manner in the SEM, were presented at the Eighth International Congress on Electron Microscopy in Canberra in 1974 (Robinson, 1974).

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