It is a rule of thumb that time delay tends to destabilize any dynamical system. This is not true, however, in the case of delayed oscillators, which serve as mechanical models for several surprising physical phenomena. Parametric excitation of oscillatory systems also exhibits stability properties sometimes defying our physical sense. The combination of the two effects leads to challenging tas...

The electronic interactions and excitation energy transfer (EET) processes of a variety of multi-porphyrin arrays with linear, cyclic and box architectures have been explored. Directly meso-meso linked linear arrays (Z(N)) exhibit strong excitonic coupling with an exciton coherence length of approximately 6 porphyrin units, while fused linear arrays (T(N)) exhibit extensive π-conjugation over t...

Excitation of solar-like oscillations is attributed to turbulent convection and takes place at the upper-most part of the outer convective zones. Amplitudes of these oscillations depend on the efficiency of the excitation processes as well as on the properties of turbulent convection. We present past and recent improvements on the modeling of those processes. We show how the mode amplitudes and...

Excitation and charge transfer cross sections for collisions of protons with hydrogen are calculated by direct solution of the time-dependent Schrödinger equation on a three-dimensional Cartesian lattice. The 2s , 2p , 3s , 3p , and 3d excitation cross sections and the 1s , 2s , 2p , 3s , 3p , and 3d charge transfer cross sections from the 1s ground state at 10-, 40-, and 100-keV incident proto...

The observation and theory of UV{excitation of molecular clouds (i.e., photodissociation regions) and the shock-excitation of molecular clouds is reviewed, with particular emphasis placed on the emission from molecular hydrogen. Recent advances in near{IR instrumentation have engendered new observations which are challenging our theoretical understanding of these fundamental physical processes....

2014 Scattering without dissociation of N+2 molecular ions by noble gas atom targets (Xe, Ar, He) is investigated. In the laboratory coordinate system, the collision energy ranges from .3 to 3 keV and the scattering angles from 0.8° to 7°. An energy loss analysis of the scattered N+2 ions shows several competitive processes: 2014 Elastic scattering and vibrational excitation. 2014 Electronic ex...

Abstract We calibrate the distorted wave Born approximation (DWBA) for electron impact excitation processes empirically. Differential cross sections (DCSs) for the excitation of the 2p53s, 2p53p, 2p54s and 2p54p configurations of Ne and the 3p54s and 3p54p configurations of Ar by electron impact are calculated using DWBA for incident energies between 20 and 100 eV. The calculated results are co...

typically, two configurations are used for energy harvesting, with different advantages: piezoelastic and piezomagnetoelastic. best performance of piezoelastic configuration is limited to its narrow bandwidth around the resonance frequency. if the excitation frequency slightly deviates from the resonance frequency, the power-out is severely reduced. to overcome this, the piezomagnetoelastic has...