Formation of dtμ in muon-catalysed fusion: a resonant rearrangement process

1996 ◽  
Vol 74 (7-8) ◽  
pp. 401-406 ◽  
Author(s):  
E. A. G. Armour

A key process in the muon-catalysed fusion cycle is a low-energy collision of a tμ atom with a DA molecule, where A is H, D, or T, which leads at appropriate incident energies, to the formation of a resonant complex containing dtμ. In this paper, methods of calculating the resonant formation rate of dtμ are discussed. A description is given of a new approach that makes use of coupled equations for the rearrangement scattering process and elements of Feshbach's theory of resonances to obtain an expression for the cross section for resonant dtμ formation. The insights gained from this approach are discussed.

Author(s):  
V. Mizuhira ◽  
Y. Futaesaku

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.


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.


1988 ◽  
Vol 92 (13) ◽  
pp. 3751-3760 ◽  
Author(s):  
Desmond J. Muller ◽  
Ruth I. McKay ◽  
Geoffrey B. Edwards ◽  
Warren D. Lawrance ◽  
Judith P. Hardy ◽  
...  

2000 ◽  
Vol 113 (18) ◽  
pp. 8026-8035 ◽  
Author(s):  
Takaaki Orii ◽  
Yoshiki Okada ◽  
Kazuo Takeuchi ◽  
Masahiko Ichihashi ◽  
Tamotsu Kondow

Fire Research ◽  
2019 ◽  
Vol 3 (1) ◽  
Author(s):  
António Correia ◽  
Paula Lopes ◽  
João Rodrigues ◽  
José Correia

The fire resistance of a steel column is highly affected by the contact between the columns and the walls, leading in general to a favorable effect due to the reduction of temperatures. However, it leads to the Thermal Bowing effect, which is not more than a differential heating in the steel cross sections, causing an inversion of bending moments and an inversion of the deflections of the column. Thus, it is necessary to accurately assess the evolution of the temperature field in the cross section of the steel elements in contact with walls. In Eurocode 3 part 1-2, the structural design of steel elements in fire situation is performed with expressions for the calculation of the section factor of steel profiles, but different cases of positioning the columns and the surrounding walls could be considered as causing extremely high thermal gradients. In this paper, a new approach for the calculation of section factors for cases not included in table 4.2 of Eurocode 3, part 1- 2 are presented. This was achieved using numerical models with finite element modelling with the ABAQUS program, varying the cross-section of the columns, orientation of the web in relation to the walls, and the position and thickness of the walls, to achieve the desired section factors.


2008 ◽  
Vol 15 (2) ◽  
pp. 179-192 ◽  
Author(s):  
Jiao Sujuan ◽  
Li Jun ◽  
Hua Hongxing ◽  
Shen Rongying

The spectral element matrix is derived for a straight and uniform beam element having an arbitrary cross-section. The general higher-order beam theory is used, which accurately accounts for the transverse shear deformation out of the cross-sectional plane and antielastic-type deformation within the cross-sectional plane. Two coupled equations of motion are derived by use of Hamilton's principle along with the full three-dimensional constitutive relations. The theoretical expressions of the spectral element matrix are formulated from the exact solutions of the coupled governing equations. The developed spectral element matrix is directly applied to calculate the exact natural frequencies and mode shapes of the illustrative examples. Numerical results of the thick isotropic beams with rectangular and elliptical cross-sections are presented for a wide variety of cross-section aspect ratios.


Sign in / Sign up

Export Citation Format

Share Document