Inverted Oscillator

The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wave function for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete and it is given as a linear function of the quantum number $n$.Comment: 4 page

Zinc Oxide Nanostructures: Synthesis and Characterization

The summary should be ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Zinc oxide (ZnO) is a wide band gap semiconductor with an energy gap of 3.37 eV at room temperature. It has been used considerably for its catalytic, electrical, optoelectronic, and photochemical properties. ZnO nanomaterials, such as quantum dots, nanorods, and nanowires, have been intensively investigated for their important properties. Many methods have been described in the literature for the production of ZnO nanostructures, such as laser ablation, hydrothermal methods, electrochemical deposition, sol-gel methods, chemical vapour deposition, molecular beam epitaxy, the common thermal evaporation method, and the soft chemical solution method. The present Special Issue is devoted to the synthesis and characterization of ZnO nanostructures with novel technological applications.

Qualitative precursory pattern before several strong earthquakes in Greece.

Μελετήθηκε η χρονική μεταβολή τριών σεισμικών παραμέτρων, δηλαδή, του αριθμού των σεισμών Ν, της παραμέτρου b-value και της εκλυόμενης σεισμικής ενέργειας, πριν από την εκδήλωση ισχυρών σεισμών στην Ελλάδα, για το χρονικό διάστημα 2000- 2008. Η ανάλυση έγινε με τη χρήση δεδομένων του καταλόγου σεισμών του Γεωδυναμικού Ινστιτούτου του Εθνικού Αστεροσκοπείου Αθηνών. Συγκεκριμένες φάσεις της χρονικής διακύμανσης των σεισμικών παραμέτρων, γύρω από σχετικές μέσες τιμές τους, σε δεδομένο χρονικό διάστημα, μπορούν να συσχετιστούν με τις φάσεις προετοιμασίας και εκδήλωσης ενός ισχυρού σεισμού. Η επαναλαμβανόμενηκανονικότητα της αυτής της συσχέτισης μπορεί να θεωρηθεί ως ποιοτικό μοτίβο (pattern) πρόδρομης συμπεριφοράς. H συνεχής παρακολούθηση της μεταβολής της σεισμικότητας και η αναγνώριση των φάσεων του παραπάνω μοτίβου, μπορεί να συμβάλει στην αξιολόγηση του σεισμικού κινδύνου και της πρόγνωσης μιας επικείμενης ισχυρής σεισμικής δραστηριότητας, σε μια δεδομένη περιοχή.The temporal variation of the seismicity, based on the analysis of three seismic parameters i.e., number of earthquakes, b-value and energy released, were investigated before several strong earthquakes occurrence in Greece the time period 2000-2008. The seismic parameters estimates were obtained by the means of new tool, suited to analyze earthquake catalogue, and visualize their spatio-temporalvariation behaviour. The seismic data used were taken from the earthquake catalogue of the Geodynamic Institute of National Observatory of Athens, Greece. The obtained temporal variation series shows significant changes around their relative mean values, which specific phases can be related to the strong earthquakes preparation stages. This relation shows remarkable temporal regularity so that itcan be establish considered as a precursor seismicity pattern. These results suggest that identification of this behaviour, by the continuous monitoring of the temporal variation of the seismic parameters, can contribute to the assessment of the current seismic hazard and to the impending strong earthquake parameters evaluation, in a given area

Stability of an Exciton bound to an Ionized Donor in Quantum Dots

Total energy, binding energy, recombination rate (of the electron hole pair) for an exciton (X) bound in a parabolic two dimensional quantum dot by a donor impurity located on the z axis at a distance d from the dot plane, are calculated by using the Hartree formalism with a recently developed numerical method (PMM) for the solution of the Schroedinger equation. As our analysis indicates there is a critical dot radius such that for radius less than the critical radius the complex is unstable and with an increase of the impurity distance this critical radius increases. Furthermore, there is a critical value of the mass ratio such that for mass ratio less than the critical value the complex is stable. The appearance of this stability condition depends both on the impurity distance and the dot radius, in a way that with an increase of the impurity distance we have an increase in the maximum dot radius where this stability condition appears. For dot radii greater than this maximum dot radius (for fixed impurity distance) the complex is always stable.Comment: 17 pages, 7 figures Applying a new numerical method which is based on the adiabatic stability of quantum mechanics, we study the stability of an exciton (X) bound in a parabolic two dimensional quantum dot by a donor impurity located on the z axis at a distance d from the dot plan