On the wave-length and structure of the K-absorption edge of cobalt

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

Download Full-text

X-Ray absorption edge elemental imaging of B. thuringienis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153038 ◽

1989 ◽

Vol 47 ◽

pp. 212-213

Author(s):

R. L. Stears

Keyword(s):

Absorption Edge ◽

Elemental Distribution ◽

X Rays ◽

Differential Absorption ◽

Synchrotron Source ◽

High Brightness ◽

X Ray ◽

Elemental Imaging ◽

Cellular Integrity ◽

X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

Download Full-text

New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179762 ◽

1990 ◽

Vol 48 (1) ◽

pp. 202-203

Author(s):

H. Rose

Keyword(s):

Spherical Aberration ◽

Wave Length ◽

Electron Wave ◽

Optical Lens ◽

Resolution Electron ◽

Rotationally Symmetric ◽

Electron Microscopes ◽

The Cost ◽

Imaging Performance ◽

Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

Download Full-text

Reflectivity spectra of Eu rich EuO near the absorption edge

Journal de Physique ◽

10.1051/jphys:01979004003031500 ◽

1979 ◽

Vol 40 (3) ◽

pp. 315-319 ◽

Cited By ~ 12

Author(s):

M. Escorne ◽

A. Mauger ◽

C. Godart ◽

J.C. Achard

Keyword(s):

Absorption Edge ◽

Reflectivity Spectra

Download Full-text

THE ELECTRONIC ABSORPTION EDGE IN STRONGLY ANISOTROPIC SUBSTANCES

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1967311 ◽

1967 ◽

Vol 28 (C3) ◽

pp. C3-57-C3-58

Author(s):

H. I. RALPH

Keyword(s):

Electronic Absorption ◽

Absorption Edge

Download Full-text

Transformation of the Continuous Laser Power on the Wave Length 10.6 Microns by the Thin-Wire Platinum Bolometer

Telecommunications and Radio Engineering ◽

10.1615/telecomradeng.v63.i5.80 ◽

2005 ◽

Vol 63 (5) ◽

pp. 46-471 ◽

Cited By ~ 2

Author(s):

V. M. Kuzmichov ◽

S. V. Pogorelov ◽

P. Kohns

Keyword(s):

Laser Power ◽

Wave Length ◽

Thin Wire ◽

Continuous Laser

Download Full-text

Buckling Behavior of Tire Breaker Structure

Tire Science and Technology ◽

10.2346/1.2150978 ◽

1983 ◽

Vol 11 (1) ◽

pp. 3-19

Author(s):

T. Akasaka ◽

S. Yamazaki ◽

K. Asano

Keyword(s):

Elastic Foundation ◽

Elastic Moduli ◽

Wave Length ◽

Bending Moment ◽

Experimental Results ◽

Automobile Tire ◽

Buckling Behavior ◽

Post Buckling ◽

Steel Cord ◽

Interlaminar Shear

Abstract The buckled wave length and the critical in-plane bending moment of laminated long composite strips of cord-reinforced rubber sheets on an elastic foundation is analyzed by Galerkin's method, with consideration of interlaminar shear deformation. An approximate formula for the wave length is given in terms of cord angle, elastic moduli of the constituent rubber and steel cord, and several structural dimensions. The calculated wave length for a 165SR13 automobile tire with steel breakers (belts) was very close to experimental results. An additional study was then conducted on the post-buckling behavior of a laminated biased composite beam on an elastic foundation. This beam is subjected to axial compression. The calculated relationship between the buckled wave rise and the compressive membrane force also agreed well with experimental results.

Download Full-text