Search results for "PACS"
showing 10 items of 141 documents
High-pressure study of the infrared active modes in wurtzite and rocksalt ZnO
2011
International audience; We present a high-pressure study of ZnO carried out in the mid- to far-infrared frequency domain with the aim of characterizing the optic modes of wurtzite and rocksalt ZnO. We obtained the pressure coefficients of the E1(TO), E1(LO), A1(TO), and A1(LO) modes of the low-pressure wurtzite phase and compare them with previous Raman measurements. The optical modes of the high-pressure rocksalt phase are infrared active, so we were able to determine their wave numbers and pressure dependencies. In the wurtzite phase, high pressure induces a slight decrease in both longitudinal and transverse effective charges. The decrease is more pronounced in the rocksalt phase.
Molecular dynamics simulations of nanometric metallic multilayers: Reactivity of the Ni-Al system
2011
The reactivity of a layered Ni-Al-Ni system is studied by means of molecular dynamics simulations, using an embedded-atom method type potential. The system, made of an fcc-Al layer embedded in fcc-Ni, is initially thermalized at the fixed temperature of 600 K. The early interdiffusion of Ni and Al at interfaces is followed by the massive diffusion of Ni in the Al layer and by the spontaneous phase formation of $B2$-NiAl. The solid-state reaction is associated with a rapid system heating, which further enhances the diffusion processes. For longer times, the system may partly lose some its $B2$-NiAl microstructure in favor of the formation of $L{1}_{2}$-${\mathrm{Ni}}_{3}\mathrm{Al}$. This st…
Macrophytes in boreal streams: Characterizing and predicting native occurrence and abundance to assess human impact
2016
Abstract Macrophytes are a structurally and functionally essential element of stream ecosystems and therefore indispensable in assessment, protection and restoration of streams. Modelling based on continuous environmental gradients offers a potential approach to predict natural variability of communities and thereby improve detection of anthropogenic community change. Using data from minimally disturbed streams, we described natural macrophyte assemblages in pool and riffle habitats separately and in combination, and explored their variation across large scale environmental gradients. Specifically, we developed RIVPACS-type models to predict the presence and abundance of macrophyte taxa at …
First measurement of the W-boson mass in run II of the Tevatron.
2007
7 pages, 4 figures.-- PACS nrs.: 14.70.Fm; 13.38.Be; 13.85.Qk.-- ISI Article Identifier: 000250140600014.-- ArXiv pre-print available at: http://arxiv.org/abs/0707.0085.-- et al.
Solutions of the LPD equation and multi-parametric rogue waves
2022
Quasi-rational solutions to the Lakshmanan Porsezian Daniel equation are presented. We construct explicit expressions of these solutions for the first orders depending on real parameters. We study the patterns of these configurations in the (x, t) plane in function of the different parameters. We observe in the case of order 2, three rogue waves which move according to the two parameters. In the case of order 3, six rogue waves are observed with specific configurations moving according to the four parameters.
From particular polynomials to rational solutions to the mKdV equation
2022
Rational solutions to the modified Korteweg-de Vries (mKdV) equation are given in terms of a quotient of determinants involving certain particular polynomials. This gives a very efficient method to construct solutions. We construct very easily explicit expressions of these rational solutions for the first orders n = 1 until 10.
N order solutions with multi-parameters to the Boussinesq and KP equations and the degenerate rational case
2021
From elementary exponential functions which depend on several parameters, we construct multi-parametric solutions to the Boussinesq equation. When we perform a passage to the limit when one of these parameters goes to 0, we get rational solutions as a quotient of a polynomial of degree N (N + 1) − 2 in x and t, by a polynomial of degree N (N + 1) in x and t for each positive integer N depending on 3N parameters. We restrict ourself to give the explicit expressions of these rational solutions for N = 1 until N = 3 to shortened the paper. We easily deduce the corresponding explicit rational solutions to the Kadomtsev Petviashvili equation for the same orders from 1 to 3.
Multi-parameters rational solutions to the mKdV equation
2021
N-order solutions to the modified Korteweg-de Vries (mKdV) equation are given in terms of a quotient of two wronskians of order N depending on 2N real parameters. When one of these parameters goes to 0, we succeed to get for each positive integer N , rational solutions as a quotient of polynomials in x and t depending on 2N real parameters. We construct explicit expressions of these rational solutions for orders N = 1 until N = 6.
Solutions to the Gardner equation with multiparameters and the rational case
2022
We construct solutions to the Gardner equation in terms of trigonometric and hyperbolic functions, depending on several real parameters. Using a passage to the limit when one of these parameters goes to 0, we get, for each positive integer N , rational solutions as a quotient of polynomials in x and t depending on 2N parameters. We construct explicit expressions of these rational solutions for orders N = 1 until N = 3. We easily deduce solutions to the mKdV equation in terms of wronskians as well as rational solutions depending on 2N real parameters.
Isomeric state of $^{80}$Y and its role in the astrophysical rp-process
2001
5 pages, 7 figures.-- PACS nrs: 21.10.Tg; 23.20.Nx; 27.50.+e.