Engaging the Masses: Encouraging All Students to “Buy Into” the Organic Chemistry “Program”

2012 ◽  
pp. 73-83
Author(s):  
N. E. Schore
Keyword(s):  
Organic Chemistry ◽  
The Masses

In situ irradiation effects studies in medium- and high-voltage TEM

1995 ◽  
Vol 53 ◽  
pp. 234-235
Author(s):  
Charles W. Allen
Keyword(s):  
Cross Section ◽  
Particle Flux ◽  
Threshold Value ◽  
High Energy ◽  
Irradiation Damage ◽  
Defect Complexes ◽  
Lattice Position ◽  
Electrons And Ions ◽  
The Masses

With respect to structural consequences within a material, energetic electrons, above a threshold value of energy characteristic of a particular material, produce vacancy-interstial pairs (Frenkel pairs) by displacement of individual atoms, as illustrated for several materials in Table 1. Ion projectiles produce cascades of Frenkel pairs. Such displacement cascades result from high energy primary knock-on atoms which produce many secondary defects. These defects rearrange to form a variety of defect complexes on the time scale of tens of picoseconds following the primary displacement. A convenient measure of the extent of irradiation damage, both for electrons and ions, is the number of displacements per atom (dpa). 1 dpa means, on average, each atom in the irradiated region of material has been displaced once from its original lattice position. Displacement rate (dpa/s) is proportional to particle flux (cm-2s-1), the proportionality factor being the “displacement cross-section” σD (cm2). The cross-section σD depends mainly on the masses of target and projectile and on the kinetic energy of the projectile particle.

Mass Media Misleading the Masses: The Propagation of Nonscientifically Supported Autism Treatments

2012 ◽  
Author(s):  
Kimberly A. Schreck ◽  
Melissa Russell ◽  
Luis Vargas ◽  
Tanya Brucie ◽  
Jennifer Hall
Keyword(s):  
Mass Media ◽  
The Masses ◽  
Autism Treatments
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