C. Vitelaru, V. Pohoata, V. Tiron, C. Costin and G. Popa
The kinetics of the sputtered atoms from the metallic target as well as the time-space distribution of the argon metastable atoms have been investigated for DC and high power pulse magnetron discharge by means of Tunable Diode – Laser Absorption Spectroscopy (TD-LAS) and Tunable Diode – Laser Induced Fluorescence (TD-LIF). The discharge was operated in argon (5-30 mTorr) with two different targets, tungsten and aluminum, for pulses of 1 to 20 μs, at frequencies of 0.2 to 1 kHz. Peak current intensity of ~100 A has been attained at cathode peak voltage of ~1 kV. The mean velocity distribution functions and particle fluxes of the sputtered metal atoms, in parallel and perpendicular direction to the target, have been obtained and compared for DC and pulse mode.
In the present work we present preliminary research on producing of transparent polycrystalline ceramics. Samarium doped Yttrium oxide (1%, 3% and 5%) and Neodymium (1%) doped YAG (Y3Al5O12) translucent ceramics were fabricated by solid-state reaction. Commercial nanopowders was used as the starting materials: Sm2O3 (6μm) and Y2O2 (20-50 nm) for Sm3+: Y2O3 and α-Al2O3, Y2O3 and Nd2O3 (20-50 nm) for Nd3+: YAG. For the preparation of Nd3+: YAG, 0.5 wt% tetraethyl orthosilicate (TEOS) was use as sintering additive, and 1 wt % PEG (polyethylene glycol-400) as dispersant.
Simulate the behavior of a quarter car suspension system with Simulink®. Consider only vertical movement of the car, neglecting roll and pitch. All movements of the car axes are modeled as having equal amplitude. The characteristic equations that describe the behavior of dynamical systems based on FBD (Free Body Diagram) of automotive suspension. We make the simulation model in six steps. In simulation we consider the damping coefficient, c, variable. The rest of parameters are constant (mass, speed and stiffness). The simulation parametrs are defined in Mathlab®. We follow the final signal created on the oscilloscope. At the end of the study, we concluded the effect of damping coefficient changes over the comfort.
In this paper it is present the influence of the wind on a parabolic antenna, in order to study this influence it was made simulations of air flow over a parabolic antenna. The simulations are made with antenna positioned at 90°, 135°. A three – dimensional finite element is simulated for determination of the antenna displacement.
N.M. Avram, M. G. Brik, C. N. Avram, M.G. Ciresan and E-L. Andreici
By using crystal field theory, the spin-Hamiltonian parameters [zero-field splitting D, the giromagnetic factors g (g|| and g⊥) and the first excited state splitting δ(2E)] for the CrLi3+ doped in LiNbO3 have been calculated from the higher-order perturbation formulas. The method used is based on the two-spin-orbit coupling parameter model, in a cluster approach. The g parameters were also calculated as a second derivative of the energy, method implemented into ORCA computer program. The results were discussed and good agreement with experimental data was demonstrated.
The article presents some new aspects and experience on the use of computer in teaching general relativity and cosmology for undergraduate students (and not only) with some experience in computer manipulation. Some years ago certain results were reported  using old fashioned computer algebra platforms but the growing popularity of graphical platforms as Maple and Mathematica forced us to adapt and reconsider our methods and programs. We will describe some simple algebraic programming procedures (in Maple with GrTensorII package) for obtaining and the study of some exact solutions of the Einstein equations in order to convince a dedicated student in general relativity about the utility of a computer algebra system.