Browsing Publications of the Faculty of Science and Technology by Issue Date
Now showing items 2140 of 2355

Active control of gustand interferenceinduced vibration of tiltrotor aircraft
(American Helicopter Society, 1989)An active control system to suppress the response of the blade bending modes of a tiltrotor aircraft to axial gusts and wing/rotor interference is described. The use of blademounted accelerometers as sensors is shown to ... 
Spectroscopy of semiconductor microstructures
(Springer US, 1989) 
Hot Electron Effects in Microstructures
(Springer New York, 1989)A series of new devices generically called “hot electron transistors” is based on the idea of improving the device performance by injecting fast electrons into thin base regions. We present here a theoretical study, based ... 
The Monte Carlo Method for Semiconductor Device Simulation
(Springer Vienna, 1989)The application of the Monte Carlo method to the simulation of semiconductor devices is presented. A review of the physics of transport in semiconductors is given, followed by an introduction to the physics of semiconductor ... 
MonteCarlo Simulation as a Novel Technique in the Study of Shallow Centers
(Institute of Physics, 1989)We present the Monte Carlo technique as a novel numerical method to investigate recombination and generation processes from shallow impurity centers. In particular, we provide a firstprinciple derivation of the microscopic ... 
Intersubband relaxation of hot carriers in coupled quantum wells
(SPIE, 1990)We use an ensemble Monte Carlo simulation of coupled electrons, holes and polar optical phonons in multiple quantum well systems to model the intersubband relaxation of hot carriers measured in ultrafast optical experiments. ... 
Effect of phonon confinement in quantum well systems
(SPIE, 1990)We discuss the role of LOphonons confinement in quantum well systems, by comparing two different phonon models that have been proposed in the literature. A critical discussion concerning the use of macroscopic approaches ... 
Radial gauge in poincare gauge fieldtheories
(AMER INST PHYSICS, 1990)The generalization of the Fock–Schwinger or ‘‘radial’’ gauge condition xiAi =0 to the gauge theories of the Poincaré group, which describe the gravitational field, is treated. It is shown that the choice of a radial gauge ... 
Forced oscillations for singular dynamical systems with an application to the restricted three body problem
(Elsevier, 1991)We consider forced dynamical systems with two degrees of freedom having singular potentials and we prove existence of infinitely many classical (noncollision) periodic solutions. These solutions have a prescribed rotation ... 
Periodic solutions for the elliptic planar restricted three body problem: A variational approach
(Plenum Press, 1991)We outline a variational approach, developed to find periodic orbits of the satellite in the elliptic restricted problem with any value of the masses of the primaries. This approach leads to a multiplicity of generalized ... 
Initial thermalization of photoexcited carriers in GaAs studied by femtosecond luminescence spectroscopy
(AMERICAN PHYSICAL SOC, 1991)Relaxation of a nonequilibrium distribution of electrons and holes in GaAs following femtosecond photoexcitation is investigated via spectrally and timeresolved luminescence. A rapid onset of luminescence over a broad ... 
Homoclinics for Lagrangian systems on Riemannian manifolds
(Dynamic Publishers Atlanta, 1992) 
Ultrafast internal thermalization of photoexcited carriers in polar semiconductors (Invited Paper)
(International Society for Optical Engineering, 1992)We present a combined experimental and theoretical study of the ultrafast internal thermalization of high energy carriers created by laser excitation. Luminescence upconversion is used to monitor the spectral and temporal ... 
On the motion of test particles in a fluctuating gravitational field
(AMER INST PHYSICS, 1992)In this paper the "free fall" motion of a test tetrad in a weak gravitational field is studied. This is done with the intention of exploring the geometry locally through geodesics and parallel transport. By use of the ... 
Zur Notwendigkeit von vegetationskundlichökologischen Untersuchungen zur Stabilität und Dynamik bodensauerer HainsimsenBuchenwälder
(Forschungszentrum, Zentralbibliothek, 1992) 
The propagator in the radial gauge
(AMER INST PHYSICS, 1992)The solutions of the equation for the propagator in the radial gauge x(mu)A(mu)(x) = 0 are studied. After finding a particular solution GAMMA(murho)(x,y), the most general solution G(murho)0(x,y) of the homogeneous ... 
Vacuum correlations in quantum gravity
(Springer, 1992)We give a lowestorder estimation of some invariant correlation functions of quantized Einstein gravity in any dimension N > 2. The nonperturbative evaluation of such functions would play an important role in the Monte ... 
Femtosecond luminescence spectroscopy of carrier thermalization in GaAs and InP
(IOP PUBLISHING LTD, 1992)Thermalization of a nonequilibrium distribution of electrons and holes generated by femtosecond photoexcitation is studied in GaAs and InP via spectrally and temporally resolved luminescence. In both materials, a rapid ...