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