35,547 research outputs found
Electrical Resistivity of SmAg, SmCu, and SmAu
The electrical resistivity of equiatomic phases of Sm with Cu, Ag and Au was measured down to 4.2°K. Anomalies were found at 10°K for SmCu and at 42°K for SmAg. The resistivity-temperature curve of SmAu has a maximum at 40°K and a minimum at 53.5°K
In search of patterns of land-use in Mexico City using logistic regression at the plot level
The study of big citiesâ tendency to decentralisation is in the current agenda to understand the structure of Latin American cities. In general, centres and subcentres are related to specific functions. According to the theories of the movement economy and centrality as a process, the urban grid shapes land use distribution through movement and therefore is the main determinant of the location of âlive centresâ, a key component of centres. Activities related to âlive centresâ include retail, catering and other movement dependent uses. However, the distribution of this kind of activity in cities like Mexico is not as spatially clear as it is in organically grown cities. In this paper we show that, nonetheless complex, there is a relationship between the location of âlive centreâ uses and spatial configuration. We use multiple logistic regression to evaluate exactly how much influence each variable has on the outcome âshopâ given the presence of all the others. The results also suggest different spatial influences for different types of retail on different scales of centres
Transmitted sound field due to an impulsive line acoustic source bounded by a plate followed by a vortex sheet
The propagation of sound due to a line acoustic source in the moving stream across a semiinfinite vortex sheet which trails from a rigid plate is examined in a linear theory for the subsonic case. A solution for the transmitted sound field is obtained with the aid of multiple integral transforms and the Wiener-Hopf technique for both the steady state (time harmonic) and initial value (impulsive source) situations. The contour of inverse transform and hence the decomposition of the functions are determined through causality and radiation conditions. The solution obtained satisfies causality and the full Kutta conditions. The transmitted sound field is composed of two waves in both the stady state and initial value problems. One is the wave scattered from the edge of the plate which is associated with the bow wave and the instability wave. These waves exist in the downstream sectors. The other is the wave transmitted through the vortex sheet which is also associated with the instability wave. Regional divisions of the transmitted sound field are identified
The Instantaneous Bethe-Salpeter Equation and Its Analog: the Breit-like Equation
We take () systems and consider the states with quantum number
as examples, to explore the different contents of the instantaneous
Bethe-Salpeter (BS) equation and its analog, Breit equation, by solving them
exactly. The results show that the two equations are not equivalent, although
they are analogous. Furthermore, we point out that the Breit equation contains
extra un-physical solutions, so it should be abandoned if one wishes to have an
accurate description of the bound states for the instantaneous interacting
binding systems.Comment: 5 pages, no figur
CsCl-type compounds in binary alloys of rare-earth metals with gold and silver
In binary alloys of silver with Sm, Tb, Ho, and Tm, and of gold with Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm, intermediate phases containing stoichiometric proportions of the two metals were found to crystallize into the CsCl (B2)-type structure. The lattice parameters of these phases are reported and a correlation has been found between these lattice parameters and the trivalent ionic radii of the rare-earth metals
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