Characterizing AEM sections: Ultramicrotomy ‘quality control’

1991 ◽  
Vol 49 ◽  
pp. 1110-1111
Author(s):  
D. Steele ◽  
T. Malis
Keyword(s):  
Quality Control ◽  
Energy Loss ◽  
Materials Science ◽  
Energy Dispersive ◽  
Factors Affecting ◽  
Hard Materials ◽  
Science Community ◽  
Detailed Nature ◽  
Significant Factors ◽  
Diamond Knife

The wide variety of modern materials (alloys, ceramics, composites, layered structures) and the strict demands of microanalytical techniques (energy dispersive and energy loss spectroscopies) has resulted in a growing use of mechanically-based techniques for preparation of AEM specimens. One of these techniques is ultramicrotomy or diamond knife sectioning, which is seeing increasing usage in the materials science community. A recent review of the field has pointed out a number of significant factors affecting section quality such as knife wear and uniformity when sectioning ‘hard’ materials. As materials ultramicrotomy diversifies and matures, more information is required concerning the detailed nature of such factors in order to understand the artifacts peculiar to the technique and ultimately produce sections of suitable AEM quality in a consistent fashion.

scholarly journals Study of the mechanical impact of agricultural machinery on the soil

2021 ◽  
Vol 937 (3) ◽  
pp. 032051
Author(s):  
I Savvateeva ◽  
G A Kokieva ◽  
D Radnaev ◽  
A G Pekhutov
Keyword(s):  
Quality Control ◽  
Field Work ◽  
Layer By Layer ◽  
Regression Equations ◽  
Factors Affecting ◽  
Work Related ◽  
Field Quality ◽  
Operations Control ◽  
Working Bodies ◽  
Significant Factors

Abstract The performance of spring field work in the best agrotechnical terms and with high quality is provided by well-trained equipment. The recommendations provide for four stages of work related to the adjustment of machines and quality control of technological operations: control of working bodies and components of machines after repairs or new ones are delivered; technological adjustments of machines; verification of technological adjustments in the field; quality control of technological operations in the field. As a criterion for the efficiency of the use of energy resources in agriculture, some foreign sources recommend the output of agricultural products per unit of energy used. The article describes the regression equations that can be used to characterize the process of grinding sedge hummocks on the root with a milling cutter. Statistically significant factors affecting the degree of grinding of the hummock are the speed of rotation of the working body, the distance between the tiers of knives, the speed of movement, the angle of taper of the rotor and the angle between the knives on adjacent tiers. Thus, layer-by-layer milling most fully meets the requirements of pre-sowing tillage on land in the oatmeal zone.

Applications of Transmission and Scanning Electron Microscopy to Materials Science

1970 ◽  
Vol 28 ◽  
pp. 462-463
Author(s):  
John L. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Materials Science ◽  
Layer Structure ◽  
Hard Materials ◽  
Muscovite Mica ◽  
Real Challenge ◽  
Scanning Electron ◽  
Diamond Knife

Applying the electron microscope to studies in Materials Science presents a real challenge to the microscopist. The variety in form and composition of sample materials calls for a repertory of techniques spanning many disciplines. For example the art of ultramicrotomy, once the exclusive province of the biologist, can now be applied to hard materials due to the development of the diamond knife by Fernandez-Moran. Figure 1 shows an ultra-microtome section of a barium-saturated muscovite mica flake. The section was cut at right angles to the (001) planes which are represented by the parallel fringes with 10Å periodicity. The alternating fringe intensity indicates substitution of barium for potassium in the layer structure.

The search for a ‘materials science’ knife in ultramicrotomy

1992 ◽  
Vol 50 (1) ◽  
pp. 390-391
Author(s):  
Tom Malis
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Analytical Electron Microscopy ◽  
Specimen Geometry ◽  
Specimen Preparation ◽  
Hard Materials ◽  
Analytical Electron ◽  
Phase Differences ◽  
Diamond Knife

Specimen preparation problems in analytical electron microscopy relating to phase differences, specimen geometry or microanalytical requirements have spurred increasing usage of diamond knife sectioning. Since many of these materials are quite hard and/or tough, many material scientists assume (hope?) that there must be a knife specifically designed for ‘hard’ materials. The fact that such a knife has not been developed is due to the fact that conventional (biological) knives have performed so well, with somewhat vague recommendations to use a 35° knife angle for reduced section compression, 45° for general usage and 55° for very hard materials such as embedded catalyst particles.

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Energy Dispersive X-Ray Measurements of thin Metal Foils

1976 ◽  
Vol 34 ◽  
pp. 426-427
Author(s):  
J. Bentley ◽  
E. A. Kenik
Keyword(s):  
Materials Science ◽  
Energy Dispersive Spectrometer ◽  
Thin Foil ◽  
Thin Metal ◽  
Energy Dispersive ◽  
Thin Specimen ◽  
X Ray ◽  
Metal Foils ◽  
Small Probe ◽  
Scanning Transmission

Instruments combining a 100 kV transmission electron microscope (TEM) with scanning transmission (STEM), secondary electron (SEM) and x-ray energy dispersive spectrometer (EDS) attachments to give analytical capabilities are becoming increasingly available and useful. Some typical applications in the field of materials science which make use of the small probe size and thin specimen geometry are the chemical analysis of small precipitates contained within a thin foil and the measurement of chemical concentration profiles near microstructural features such as grain boundaries, point defect clusters, dislocations, or precipitates. Quantitative x-ray analysis of bulk samples using EDS on a conventional SEM is reasonably well established, but much less work has been performed on thin metal foils using the higher accelerating voltages available in TEM based instruments.

Electron holography of interfaces in electroceramics

1993 ◽  
Vol 51 ◽  
pp. 1088-1089
Author(s):  
Vinayak P. Dravid ◽  
V. Ravikumar ◽  
Richard Plass
Keyword(s):  
Space Charge ◽  
Direct Evidence ◽  
Materials Science ◽  
Theoretical Work ◽  
Electron Holography ◽  
Resolution Limit ◽  
Interference Phenomenon ◽  
X Ray ◽  
Electron Sources ◽  
Science Community

With the advent of coherent electron sources with cold field emission guns (cFEGs), it has become possible to utilize the coherent interference phenomenon and perform “practical” electron holography. Historically, holography was envisioned to extent the resolution limit by compensating coherent aberrations. Indeed such work has been done with reasonable success in a few laboratories around the world. However, it is the ability of electron holography to map electrical and magnetic fields which has caught considerable attention of materials science community.There has been considerable theoretical work on formation of space charge on surfaces and internal interfaces. In particular, formation and nature of space charge have important implications for the performance of numerous electroceramics which derive their useful properties from electrically active grain boundaries. Bonnell and coworkers, in their elegant STM experiments provided the direct evidence for GB space charge and its sign, while Chiang et al. used the indirect but powerful technique of x-ray microchemical profiling across GBs to infer the nature of space charge.

Stopping-power determination for compound by EELS

1994 ◽  
Vol 52 ◽  
pp. 948-949 ◽  
Author(s):  
David C. Joy ◽  
Suichu Luo ◽  
John R. Dunlap ◽  
Dick Williams ◽  
Siqi Cao
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Average Energy ◽  
Stopping Power ◽  
Accurate Information ◽  
Power Calculation ◽  
Coulomb Collisions ◽  
Electron Energy Loss

In Physics, Chemistry, Materials Science, Biology and Medicine, it is very important to have accurate information about the stopping power of various media for electrons, that is the average energy loss per unit pathlength due to inelastic Coulomb collisions with atomic electrons of the specimen along their trajectories. Techniques such as photoemission spectroscopy, Auger electron spectroscopy, and electron energy loss spectroscopy have been used in the measurements of electron-solid interaction. In this paper we present a comprehensive technique which combines experimental and theoretical work to determine the electron stopping power for various materials by electron energy loss spectroscopy (EELS ). As an example, we measured stopping power for Si, C, and their compound SiC. The method, results and discussion are described briefly as below.The stopping power calculation is based on the modified Bethe formula at low energy:where Neff and Ieff are the effective values of the mean ionization potential, and the number of electrons participating in the process respectively. Neff and Ieff can be obtained from the sum rule relations as we discussed before3 using the energy loss function Im(−1/ε).

The Influence of Specimen Thickness in Quantitative Electron Energy Loss Spectroscopy

1980 ◽  
Vol 38 ◽  
pp. 112-113
Author(s):  
Nestor J. Zaluzec
Keyword(s):  
Quantitative Analysis ◽  
Adverse Effects ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Light Element ◽  
Specimen Thickness ◽  
Element Analysis ◽  
Electron Energy Loss

The application of electron energy loss spectroscopy (EELS) to light element analysis is rapidly becoming an important aspect of the microcharacterization of solids in materials science, however relatively stringent requirements exist on the specimen thickness under which one can obtain EELS data due to the adverse effects of multiple inelastic scattering.1,2 This study was initiated to determine the limitations on quantitative analysis of EELS data due to specimen thickness.

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