Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 11 (1989), S. 1307-1325 
    ISSN: 0392-6737
    Keywords: General theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Un modello a principio semiprimo (SFM) che usa il concetto di uno strato rigido con movimento relativo al suo nucleo per simulare la risposta degli elettronid è stato proposto per studiare la dinamica reticolare dei metalli di transizione che appartengono alla struttura h.c.p. Si descrive l’interazione a lungo raggio tra ione-ione e strato-strato via elettroni di conduzione usando il potenziale schermato e l’interazione a corto raggio è descritta usando forze spaiate a due e tre corpi tra i nuclei e gli strati. Sono state calcolate e confrontate con i risultati sperimentali le curve di dispersione dei fononi con costanti elastiche e le proprietà termiche, cioè calore specifico del fononi con costanti elastiche e le proprietà termiche, cioè calore specifico del reticolo, la temperatura caratteristica di Debye di tre importanti metalli di transizione (Zr, Hf, Ti).
    Abstract: Резюме Для исследования динамики решетки переходных металлов, которые имеют гексагональную с плотной упаковкой структуру, предлагается модель, использующая концепцию жесткой оболочки, движущейся относительно ее ядра, чтобы смоделировать откликd-электронов. Описывается длиннодействующее взаимодействие между ионами, а также между оболочками через электроны проводимости, используя экранированный потенциал. Короткодействующее взаимодействие описывается с помощью двух-частичных и трех-частичных неспаренных сил между остовами и оболочками. Вычисляются упругие постоянные, фононные дисперсионные кривые и тепловые свойства, т.е. удельная теплоемкость решетки, характеристическая температура Дебая для трех переходных металлов решетки, характеристическая температура Дебая для трех переходных металлов (Zr, Hf, Ti). Полученные результаты сравниваются с экспериментальными данными.
    Notes: Summary A semi-first principle (SFM) model using the concept of a rigid-shell moving relative to its nucleus to simulate the response of thed-electrons has been proposed for studying lattice dynamics of transition metals which belong to the h.c.p. structure. The long-range interaction between ion-ion as well as shell-shell via conduction electrons is described using the screened potential and the short-range interaction is described using two-body and three-body unpaired forces between cores as well as shells. Elastic constants, phonon dispersion curves and thermal properties,e.g. lattice specific heat, Debye characteristic temperature of three prominent transition metals (Zr, Hf, Ti) have been calculated and compared with the experimental results.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 5 (1985), S. 365-377 
    ISSN: 0392-6737
    Keywords: Phonons and vibrations in crystal lattices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è presentata un’analisi del ruolo delle forze non appaiate nella dinamica reticolare di metalli h.c.p. limitati da s.p. rispetto a Mg e Zn. L’energia totale è stata estesa fino al terz’ordine nel potenziale elettrone-ione. La matrice dinamica contiene termini che originano da interazioni del tipo a coppie tra ioni cosiccome contributi dovuti a somme di forze a tre corpi non accoppiati. Tali forze, che derivano dall’inclusione di termini di terz’ordine, sono del tipo a corto raggio e possiedono le caratteristiche di forze tensoriali. Si conclude che l’interazione a tre corpi non appaiata è necessaria per spiegare la dinamica reticolare di metalli h.c.p. Le curve teoriche di dispersione sono confrontate coi dati sperimentali. Si è trovato un buon accordo tra i risultati teorici e sperimentali lungo le direzioni di simmetria.
    Notes: Summary An analysis of the role of the nonpair forces in the lattice dynamics of s.p. bonded h.c.p. metalsviz. Mg and Zn has been presented. The total energy has been extended up to third order in the electron-ion pseudopotential. The dynamical matrix contains the terms arising from central pairwise interactions between the ions as well as contributions due to sums of nonpair three-body forces. Such forces, arising from the inclusion of third-order terms, are of short-range nature and possess the character of tensor forces. It is concluded that the nonpair three-body interaction is necessary for explaining the lattice dynamics of h.c.p. metals. The theoretical dispersion curves are compared with the experimental data. Good agreement is found between the computed and experimental results along the symmetry directions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 378 (1995), S. 658-658 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR — Kipling, had he been alive, would be glad to know that the fawning, loyal subject of colonial days looking up to his overlord for justice is not extinct. B. N. Dwivedi's letter (Nature 376, 545; 1995) shows the same sovereign contempt and distrust in which the colonial subject held his ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...