3 research outputs found
Optically induced coherent intra-band dynamics in disordered semiconductors
On the basis of a tight-binding model for a strongly disordered semiconductor
with correlated conduction- and valence band disorder a new coherent dynamical
intra-band effect is analyzed. For systems that are excited by two, specially
designed ultrashort light-pulse sequences delayed by tau relatively to each
other echo-like phenomena are predicted to occur. In addition to the inter-band
photon echo which shows up at exactly t=2*tau relative to the first pulse, the
system responds with two spontaneous intra-band current pulses preceding and
following the appearance of the photon echo. The temporal splitting depends on
the electron-hole mass ratio. Calculating the population relaxation rate due to
Coulomb scattering, it is concluded that the predicted new dynamical effect
should be experimentally observable in an interacting and strongly disordered
system, such as the Quantum-Coulomb-Glass.Comment: to be published in Physical Review B15 February 200
Vorausberechnung der praezisen Werkzeugkontur beim Spritzgiessen. Teilvorhaben: Verbesserung der Schwindungs- und Verzugsberechnung durch Entwicklung und Implementierung neuer Stoffwertfunktionen, Kristallisations- und Faserorientierungsmodelle Abschlussbericht
The final report on warpage and shrinking of injection molded parts is presented. With the aid of process simulation methods, short-term technological advances are possible for the injection molding technology. However, simplified simulation models may reveal insufficient predictions of the shrinkage and warpage of semi-crystalline plastic materials. The presented report focuses at simulations of the temperature effects and the p,v,T behavior of polymers. Therefore, various models for the description of thermal materials data and the crystallization kinetics are presented and evalutated, including CADMOULD. Only the coefficient of heat transition could not be characterized adequately; therefore, more detailed studies must be carried out.SIGLEAvailable from TIB Hannover: F01B1783 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman