Effect of low-energy alpha-particles irradiation on surface structure and physical-mechanical properties of high-purity tungsten

2016 ◽  
Author(s):  
T. M. Aldabergenova ◽  
S. B. Kislitsin ◽  
A. S. Larionov ◽  
G. S. Yar-Mukhamedova
Keyword(s):  
Mechanical Properties ◽  
Surface Structure ◽  
High Purity ◽  
Alpha Particles ◽  
Low Energy

Modification of surface structure and mechanical properties in polyimide aerogel by low-energy proton implantation

2020 ◽  
Vol 403 ◽  
pp. 126364
Author(s):  
You Wu ◽  
Dandan Ju ◽  
Hao Wang ◽  
Huiyang Zhao ◽  
Chengyue Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Structure ◽  
Low Energy ◽  
Energy Proton ◽  
Proton Implantation

scholarly journals Colloidal CdSe nanocrystals are inherently defective

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis
Keyword(s):  
Charge Transfer ◽  
Energy Spectrum ◽  
Surface Structure ◽  
Short Range ◽  
Surface Defects ◽  
Low Energy ◽  
Lewis Base ◽  
Cdse Nanocrystals ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

Angular Distribution of Rotons Generated by Alpha Particles in Superfluid Helium: A Possible Tool for Low Energy Particle Detection

1995 ◽  
Vol 74 (16) ◽  
pp. 3169-3172 ◽  
Author(s):  
S. R. Bandler ◽  
S. M. Brouër ◽  
C. Enss ◽  
R. E. Lanou ◽  
H. J. Maris ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Superfluid Helium ◽  
Alpha Particles ◽  
Low Energy ◽  
Energy Particle ◽  
Particle Detection

Experiments on the reaction T( d , n ) 4 He I. The 90° cross-section

1951 ◽  
Vol 204 (1079) ◽  
pp. 488-499 ◽  
Keyword(s):  
Cross Section ◽  
Heavy Water ◽  
Incident Beam ◽  
Absolute Magnitude ◽  
Alpha Particles ◽  
Low Energy ◽  
Energy Relation ◽  
Conventional Theory ◽  
Simultaneous Observation ◽  
The Cross

The 90° cross-section of the reaction 3 1 H( d , n ) 4 2 He has been investigated over the energy range 100 to 200 keV (energy of bombarding triton) using the 200 keV accelerating set of the establishment. Two methods have been used. As a preliminary experiment the yield of alpha-particles from a thick heavy-ice target was measured per unit charge of incident beam, as a function of deuteron energy, and the variation of cross-section deduced from the gradient of this excitation curve and the range energy relation for tritons in heavy water. Secondly, a comparison was made between the yield of alpha-particles from the D-T reaction and the yield of protons from the D-D reaction when a beam containing both deuterons and tritons was passed through a heavy-water vapour target. (The energy loss in this target was calculated as only a few hundred electron volts.) To do this a simultaneous observation was made of the protons and alpha-particles using the same counter. The values obtained for the cross-section have been compared with the resonance formulae given by Bretscher & French (1949) and by Tascbek, Everhart, Gittings, Hemmendinger & Jarvis (1948) and have been found to be in disagreement with formulae of this type. From considerations of the absolute magnitude of the cross-section it has been deduced that no conventional theory postulating reaction at a distance equal to the sum of the nuclear radii (cf. Konopinski & Teller 1948) will be able to explain this reaction. The evidence for a low-energy resonance (Allan & Poole 1949) is thought to be inconclusive.

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