Diffusion of Pu in U02

1963 ◽  
Vol 1 (4) ◽  
Author(s):  
F. Schmitz ◽  
R. Lindner

SummaryThe diffusion ofComparison has been made with the self-diffusion of Uranium by a new technique of differential diffusion measurements. It results that the activation energy for Plutonium diffusion is 6.0 kcals less than that of Uranium diffusion.

1998 ◽  
Vol 76 (1) ◽  
pp. 47-62
Author(s):  
H Saygin

The major problem of the self-shielding methods based on the equivalence principle is the difficulty of calculating the dilution cross section σe with adequate precision. We have proposed a new self-shielding procedure that contains a new technique to calculate dilution cross section. We have compared our method to the generalized Stamm'ler method. Accuracy of each computing approach is determined using reference results obtained from a micro-group slowing-down code named CESCOL.


2000 ◽  
Vol 55 (3-4) ◽  
pp. 412-414 ◽  
Author(s):  
Hiroyuki Ishida

Abstract The reorientation of the tetrahedral complex anion ZnCl42- and the self-diffusion of the cation in (CH3NH3)2ZnCl4 were studied by 1H NMR spin-lattice relaxation time (1H T1) experiments. In the second highest-temperature phase, the temperature dependence of 1H T1 observed at 8.5 MHz could be explained by a magnetic dipolar-electric quadrupolar cross relaxation between 1H and chlorine nuclei, and the activation energy of the anion motion was determined to be 105 kJ mol -1 . In the highest-temperature phase, the activation energy of the self-diffusion of the cation was determined to be 58 kJ mol -1 from the temperature and frequency dependence of 1H T1


PMLA ◽  
1970 ◽  
Vol 85 (5) ◽  
pp. 1106-1115
Author(s):  
Jack Undank

Vauvenargues describes both the social and philosophical world as a battleground of conflicting interests, thereby extending the premises of Classical ego psychology into the Enlightenment. His heroes, political and philosophical, may be seen as seeking a new kind of peace in their triumph over men and systems metaphorically portrayed as rigid, blind, and imprisoned within their own egocentricity. His ideal philosopher reconciles all conflicting views in an overarching system of truth. Ultimately this system rests not so much on principles of logic as on the personal qualities of the thinker, his “pénétration,” “profondeur,” and “étendue d'esprit,” his ability to transcend the self. In the partially Spinozistic, partially rococo, and eminently conciliatory vision vouchsafed the true philosopher, variety submits to organic order, concepts and people maintain their autonomy, yet grow interrelated. Apparent contradictions vanish in the fullness of truth. Vauvenargues's early works suffer from his inability to articulate this vision within conventional, discursive forms. In the posthumous Caractères, he invents a new technique, the “définition,” which strikingly parallels the idiom of contemporary fictional realism. By capturing visible phenomena and exposing their paradoxically contrasting inner mechanisms, Vauvenargues reveals both the method and the nature of the truth he repeatedly struggled to express.


1962 ◽  
Vol 17 (3) ◽  
pp. 195-198
Author(s):  
Lars-Erik Wallin

The diffusion coefficient of zinc in molten zinc bromide has been re-measured with a new technique over the temperature interval 400 - 565 °C. The result is a downward shift of the values as compared to previous data. Assuming a relation of the formD=D0·e-Q/RTthe values of the constants are:D0=0,405 cm2/sec, Q = 19 000 cal/mole.


1989 ◽  
Vol 163 ◽  
Author(s):  
Maria Ronay ◽  
R.G. Schad

AbstractDiffusion studies of mono and bilaycrs of transition-metal films on silicon showed that the formation of η′ —Cu3Si lowers the formation temperature of subsequently forming ReSi2 by 400°C. This is due to the creation of a large amount of silicon self-interstitials accompanying the formation of the copper suicide, which lowers the activation energy for silicon diffusion. The generalization of this result - stating that the formation of all suicides, in which the volume density of silicon is much larger than in elementary silicon injects silicon self-intcrstitials into the silicon lattice - gives new insight into suicide formation, silicide-cnhanccd dopant diffusion and the self-diffusion of silicon itself6.


1976 ◽  
Vol 4 (4) ◽  
pp. 421-429 ◽  
Author(s):  
J. M. Grzybowski ◽  
B. R. Carr ◽  
B. M. Chadwick ◽  
D. G. Cobbold ◽  
D. A. Long

2005 ◽  
Vol 20 (5) ◽  
pp. 1146-1153 ◽  
Author(s):  
Mikhail I. Mendelev ◽  
Hao Zhang ◽  
David J. Srolovitz

We examined the influence of the boundary plane on grain-boundary diffusion in Ni through a series of molecular dynamics simulations. A series of 〈010〉 ∑5 tilt boundaries, including several high symmetry and low symmetry boundary planes, were considered. The self-diffusion coefficient is a strong function of boundary inclination at low temperature but is almost independent of inclination at high temperature. At all temperatures, the self-diffusion coefficients are low when at least one of the two grains has a normal with low Miller indices. The grain boundary self-diffusion coefficient is an Arrhenius function of temperature. The logarithm of the pre-exponential factor in the Arrhenius expression was shown to be nearly proportional to the activation energy for diffusion. The activation energy for self-diffusion in a (103) symmetric tilt boundary is much higher than in boundaries with other inclinations. We discuss the origin of the boundary plane density–diffusion coefficient correlation.


2010 ◽  
Vol 297-301 ◽  
pp. 1371-1376
Author(s):  
Dezső L. Beke

There are a number of well-known empirical relations for diffusion in solids. For example the proportionality between the self-diffusion activation energy and melting point or between the entropy of the diffusion and the ratio of activation energy and the melting point (Zener rule) are perhaps the best known ‘rules of thumb’. We have shown earlier in our Laboratory, that these relations are direct consequences of the similarity of interatomic potentials seen by ions in solids. On the basis of this, similar relations were extended for impurity and self diffusion in binary solid alloys. In this paper, results for binary liquid mixtures will be reviewed. First a minimum derivation of the temperature dependence of the self-diffusion coefficient, D, is presented (minimum derivation in the sense that it states only that the reduced (dimensionless) D should be a universal function of the reduced temperature), using the similarity of interatomic potentials and dimensional analysis. Then the extension of this relation for determination of the pressure and composition dependence of the self-diffusion coefficients is described using pressure and composition dependent scaling parameters (melting point, atomic volume and mass). The obtained universal form (valid for binary liquid alloys) is very useful for the estimation of the temperature, composition and pressure dependence of the self-diffusion coefficients. Finally, the relation for the ratio of the impurity and self-diffusion coefficients is derived.


2011 ◽  
Vol 53 (11) ◽  
pp. 2194-2200 ◽  
Author(s):  
A. A. Vasilyev ◽  
S. F. Sokolov ◽  
N. G. Kolbasnikov ◽  
D. F. Sokolov

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