Mircea Victor Rusu

Dynamic scaling method and interface growth

The dynamic scaling approach is an important tool for describing the time evolution of rough interfaces. It computes dynamic scaling parameters alpha and beta, which characterize surface and time correlations. Applications of dynamic scaling to random deposition and ballistic deposition are discussed. A model of random adsorption on fractal substrates is presented. Then the influence of surface diffusion on adsorption is analyzed. The dependence of alpha and beta on the substrate fractal dimension, together with the dependence of the fractal dimension of the gas-solid interface on adsorption coverage are computed.

Adhesion AFM Applied to Lipid Monolayers. A Fractal Analysis

Adhesion Atomic Force Microscopy images of lipid monolayers on mica are studied using methods of image processing and fractal analysis. We show that liquid-condensed domains are fractal. Free energy computation indicates that fractal domains have an advantage over circular domains as far as free energy is concerned. This may provide an answer to the question why LC domains are fractal.

COMPUTER SIMULATIONS OF FRACTAL SURFACES: APPLICATION IN ADSORPTION

A computer program which is able to simulate adsorption on fractal surfaces was developed. The fractal surfaces are generated as Takagi surfaces. The computer program is based on a DLA-algorithm. Adsorption was simulated in different conditions: 1. equivalent active sites (homogeneous surfaces); 2. active sites with different adsorption probabilities; the probability associated with every active site is computed using a van der Waals potential. Our simulation allows us to explore the actual structure of the gas-solid interface and to study the sensitivity to energetic disorder. The fractal dimension of gas-solid interface vs. adsorption coverage curves are computed.

SIMULATION OF CO CHEMISORPTION ON Pt SUPPORTED ON FRACTAL SURFACES

CO chemisorption on Pt supported on fractal surfaces was simulated in order to compute chemisorption dimension and active sites fractal dimension. Pt deposition was simulated using different models on both fractal and planar surfaces. The potential energy surface with two adsorption positions model was used to compute Pt–CO interaction and a Lennard–Jones 6–12 potential was used to simulate CO–CO interaction. Two Pt phases on fractal surface, one at low concentration — the dispersed phase and the second at high concentration — the aggregated phase characterized by weak interactions with support are obtained. The results are in accord with experimental data of CO chemisorption on Pt supported on γ-alumina. Computed data obtained for planar support are compared with those obtained on fractal support. The effect of fractal support on chemisorption data is underlined.

Astronomy in Fortress of Oradea

The relatively recent “re‐discovery” of some seemingly forgotten documents speaks about the existence of an early astronomical observatory as well as an elevated scientific and cultural environment in the early city of Oradea (Varadinum—first mentioned in 1113). This is the starting point of this communication paper and in this work we are presenting findings and some possible position of the so called “ZERO MERIDIAN” from Oradea. While working on these documents, we came to better understand the cultural and scientific development of this town throughout its history.

Moments of astronomy education in Bucharest

Selection from past astronomy education, activities, textbooks and curricula will be presented. Didactic aspects and comparison with physics education will be exemplified. The astronomy/science education along the time in Romania was roughly divided in four directions: very broad information texts for everybody, popular science, school textbooks, science fictions and astronomy/science literature, and exemplified using original texts. All categories were intended to extend literacy in science, but in different ways. The trends for different periods were outlined. The teaching of astronomy and astrophysics in high school and universities, with special attention to the Faculty of Physic from University of Bucharest are presented. Suggestions for future improvement of both related fields, physics and astronomy, will be one of the outcomes of our communication.

Teaching of astrophysics at the University of Bucharest, Romania, in the last 50 years

In the University of Bucharest, by tradition, Astronomy was developed within the Department of Mechanics dominated by outstanding mathematicians. From this reason, for a long time, Astronomy was sustained mainly in the Faculty of Mathematics. Some lectures were given in the Faculty of Physics, too. After 1990, the astrophysics became a systematic course at the Faculty of Physics, and gradually the number of topics studied increased. In a relatively short time, reasonably good results were obtained, being now involved in many international cooperations in astrophysics, giving master degree in astrophysics to the Romanian students. During this time the Faculty of Physics of Bucharest University was and still is involved in many European programs, like TEMPUS and ERASMUS/SOCRATES (with: France, Germany, Italy, Greece) and with other countries, as USA or Australia, on specific fields of astrophysics. The Faculty organized for the first time the observation of a total solar eclipse (TSE 1999), when it hosted t...