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Non Contact Vibration Measurements on Parabolic Surface Antenna

Abstract

In this paper it is present a non contact method for 3D measurements on parabolic surface antenna. In order to obtain modal parameters and modal shapes of a parabolic surface antenna a Microflown USP (Ultimate Sound Probe) is used. Microflown sensors are close to antenna and can be used for the non contact measurement of the normal component of the structural velocity.

Open access
On The Information-Theoretical Entropy for Some Quantum Oscillators

Abstract

The information-theoretical entropy, also called the “classical” entropy, was introduced by Wehrl in terms of the Glauber coherent states (CSs) | z > , i.e. the CSs corresponding to the one-dimensional harmonic oscillator (HO-1D). In the present paper, we have focused our attention on the examination of the information-theoretical entropy, i.e. the Wehrl entropy, for both the pure and the mixed (thermal) states of some quantum oscillators.

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Problems in Teaching Physics at Technical Universities

Abstract

The paper deals with the problem of decreasing level of knowledge of university students due to the changes of the school system in Slovakia. As the commonly repeated words connected with education in 21st.century are key competencies, we tried to look at the problems and challenges in teaching physics from this point of view. The role of classical experiments in our computerized world is also discussed.

Open access
Annals of West University of Timisoara - Physics
The Journal of West University of Timisoara
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Bending Of Adsorbed FCN And FNC Molecules Induced By The Renner-Teller Effect

Abstract

It is shown that the bending of FCN and FNC molecules adsorbed on Si (100) - (2 × 1) surface, is due to the Renner-Teller effect induced by the orbital charge transfers by adsorption. From ab initio calculations of free FCN and FNC and the molecules adsorbed on the model Si9H12 cluster, the orbital charge transfers to and from the molecules were calculated, the vibronic coupling constants were estimated, and the curvature K of the adiabatic potentials for the bending coordinate of adsorbed molecules was evaluated. Calculations show that for both side-on adsorbed species, as well as for end-on adsorbed FNC molecule K<0 that leads to their bending. For the end-on adsorbed FCN K>0, and this molecule remains linear

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Calculation Of The Crystal Field Parameters For Eu3+ Doped In SrAl2O4 And SrIn2O4 Spinels

Abstract

Strontium aluminate (SrAl2O4) and the indium aluminate (SrIn2O4) spinels have been proven to be efficient host materials, which offer the possibility of generating broadband emission after doping with rare earth trivalent ions. The present work is devoted to the calculation of the crystal field parameters and the energy levels of the trivalent europium doped in SrAl2O4 and SrIn2O4 spinels, using the superposition model of the crystal field. Using the intrinsic parameters for Eu3+-O2− bonds, and the geometry structure of the each crystal, we modeled the CFPs and simulated the low-lying energy levels schemes. The obtained results are compared with the experimental data and discussed.

Open access
Calculation Of The Judd - Ofelt Parameters Of The ZnAl2O4: Eu3+

Abstract

Zinc aluminate (ZnAl2O4) doped with rare earth metal ions has been investigated most frequently because of the unique luminescent properties resulting from its stability and high emission quantum yields. The present work is devoted to calculate the Judd-Ofelt parameters (Ω2, Ω4 and Ω6) of the trivalent europium doped in ZnAl2O4 spinel, the quality factor (Q) and the branching ratio (β).

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Cavitational Iron Microparticles Generation By Plasma Procedures For Medical Applications

Abstract

The paper presents the experimental installation for the production, in argon plasma, of cavitational iron microparticles (pore microspheres, microtubes and octopus-shaped microparticles). Experimental results are presented and discussed and it is shown that absorbant particles with a minimum iron content are obtained by the plasma procedures

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Discrete O(1,4) Transformations And New Scalar Quantum Modes On The De Sitter Spacetime

Abstract

It is shown that the isometry group of the de Sitter spacetime includes two different three-dimensional Abelian subgroups which transform between themselves through a discrete isometry corresponding to the time reversal in the five-dimensional Minkowski spacetime embedding the de Sitter one. The eigenfunctions of the generators of these Abelian subgroups form two different sets of quantum modes correlated by the mentioned isometry.

Open access
Efficient Second Harmonic Generation Of Blue-Violet Light In Noncritical Type-I Phase Matching

Abstract

Single crystals of Y1−xRxCa4O(BO3)3 (R = Sc or Lu) of good quality have been grown from the melt by the Czochralski pulling method. The chemical compositions of the grown crystals were determined. Type-I noncritical phase matching (NCPM) wavelengths for second harmonic generation (SHG) in Y1−xRxCa4O(BO3)3 grown crystals were also determined.

Open access