A new method to determine the distance of electron tunneling transfer and its application to recombination of paramagnetic radiation deffects in CaO

1985 ◽  
Vol 27 (2) ◽  
pp. 259-262 ◽  
Author(s):  
Yu. I. Aristov ◽  
V. N. Parmon
Keyword(s):  
Electron Tunneling ◽  
New Method ◽  
Tunneling Transfer

Photoluminescence study of electron tunneling transfer in coupled‐quantum‐well structures

1995 ◽  
Vol 78 (5) ◽  
pp. 3221-3229
Author(s):  
Naofumi Shimizu ◽  
Tomofumi Furuta ◽  
Takao Waho ◽  
Masaaki Tomizawa ◽  
Takashi Mizutani
Keyword(s):  
Quantum Well ◽  
Electron Tunneling ◽  
Quantum Well Structures ◽  
Photoluminescence Study ◽  
Tunneling Transfer ◽  
Coupled Quantum Well

Selective Sampling and Orientation of Non-Homogeneous Tissues

1968 ◽  
Vol 26 ◽  
pp. 98-99
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Random Sampling ◽  
New Method ◽  
Microscope Examination ◽  
Small Areas ◽  
Selective Sampling ◽  
Large Numbers ◽  
Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

A new method for the determination of nitrates

1960 ◽  
Vol 23 ◽  
pp. 227-232 ◽  
Author(s):  
P WEST ◽  
G LYLES
Keyword(s):  
New Method
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