Arhivă — Seria A

1

A PHENOMENOLOGICAL UNIVERSALITIES APPROACH TO THE ANALYSIS OF PERINATAL GROWTH DATA

Pier Paolo DELSANTO, Antonio S. GLIOZZI, Dan A. IORDACHE,Caterina GUIOT

The Phenomenological Universalities (PUN) approach has been developed by P.P. Delsanto and collaborators during the past four years. It represents a new tool for the analysis of experimental datasets and cross-fertilization among different fields, from physics/engineering to medicine and social sciences. In fact, it al…

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2

APPLICATION OF FRACTIONAL DERIVATIVE TO THE RELAXATION OF LASER TARGET

Liliana PREDA, Mona MIHAILESCU, Alexandru PREDA

This paper focuses on the relation between fractional derivative and temperature relaxation of a wire after irradiation with a short laser pulse. We propose a fractional relaxation equation from which one obtains the transfer function of temperature, the impulse response. The general solution of fractional differential…

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3

CONTINUOUS SEPARATION OF WHITE BLOOD CELL FROM BLOOD IN A MICROFLUIDIC DEVICE

Florina S. ILIESCU, Andreea P. STERIAN , Elena BARBARINI, Marioara AVRAM, Ciprian ILIESCU

This paper presents a magnetophoretic separation method on a chip of white blood cells from blood under continuous flow. The separation of red blood cells from the whole blood is performed using a high gradient magnetic separation method under continuous flow to trap the particles inside the device. The device is fabri…

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4

PERFORMANCE ESTIMATION OF BUCHAREST MULTIWAVELENGTH LIDAR DURING THE EARLI09 CAMPAIGN

Livio BELEGANTE, Doina NICOLAE, Camelia TALIANU, Viorel VULTURESCU

Atmospheric aerosols, including clouds, play an important role in the earth’s radiation budget. Their vertical structure is complex and changing continuously. Lidars make use of a laser to excite the atmosphere. The backscatter signal is detected and analyzed. Apart from noise limitations (background radiation and elec…

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5

MODELLING THE HYPERBOLOID ELASTIC SHELL

Carlo CATTANI, Paul E. STERIAN

This paper deals with the momentless state equations of a hyperboloid elastic shell which is obtained as a surface of revolution. The compatibility conditions are investigated and used to derive a class of analytical solutions. A computer model of given initial-boundary problems show some nonlinear effects such as the …

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6

THE OPTICAL STARK EFFECT IN PARABOLIC QUANTUM WELL WIRES UNDER HYDROSTATIC PRESSURE

Ecaterina C. NICULESCU, Alexandru LUPASCU, Liliana M. BURILEANU

In this paper we study the properties of the quantum-well wires under simultaneous action of hydrostatic pressure and high-frequency laser field. Calculation of the optical Stark effect is carried out in the effective mass approximation. Different geometries concerning the size of GaAs/AlGaAs quantum wires as well as t…

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7

MODELLING OF MULTI-LAYERED QUANTUM WELL PHOTOVOLTAIC CELLS

Vladimir IANCU, Mihai Rãzvan MITROI, Laurenþiu FARA

The present paper discusses the modelling of the multi-layered quantum well photovoltaic cells. The quantum confinement of a semiconductor induces new energy levels, located in the band gap, as well as resonant levels located in the conduction and valence bands. These levels allow supplementary absorption in visible an…

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8

SYNTHESIS AND CHARACTERIZATION OF CONDUCTIVE POLYMERS WITH ENHANCED SOLUBILITY

Iuliana DUMITRESCU, Cristian-Andi NICOLAE, Ana Maria MOCIOIU, Raluca

The polyaniline synthesis in the presence of dodecylbenzenesulphonic acid (DBSA) and polyvinylpirolidone (PVP) was studied in order to improve the solubility of polyaniline (PANI) in water. UV-VIS, FT-IR spectroscopy and DSC/TGA/MS have been used to characterize and monitor the progress of the polymerization. Using an …

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9

EXPERIMENTAL INVESTIGATION OF THE LASER-DRILLED HOLES IN ALUMINIUM

Mihai STAFE, Ionut VLADOIU, Constantin NEGUTU, Ion M. POPESCU

We investigate experimentally the aluminium drilling by using multiple nanosecond laser pulses at 532nm wavelength in open air. We analyzed the surface morphology around the craters and the ablation rate as a function of laser fluence. The results indicate that the ablation rate of aluminium increases exponentially wit…

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10

SPACE PHASE CHARACTERISTICS OF A TYPICAL I-125 BRACHY SEED, MODELLED BY MONTE CARLO TECHNIQUES

Iulian BÃDRÃGAN, Paul STERIAN

The current clinical practice requires double-checking the dose calculations generated by the treatment planning system (TPS) using an independent method. One class of methods employs Monte Carlo techniques. While there are a number of such systems in place designed for external radiation beams, there is a need for a s…

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11

EVALUATION OF THE DEBYE LENGTH FOR A NEMATIC LIQUID CRYSTAL ALIGNED WITH CONDUCTIVE POLYMERS

Constanta DASCALU, Ruxandra ATASIEI, Matei D. RAICOPOL

Electric conduction measurements were performed to estimate ionic charge densities and Debye screening length within a nematic liquid crystal aligned with conductive polymers. The study has been carried out on standard sandwich symmetric cells filled with nematic liquid crystal 5CB. Planar orientation was induced using…

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12

MODELING WITH THE CHAOS GAME (I). SIMULATING SOME FEATURES OF REAL TIME SERIES

Constantin P. CRISTESCU, Cristina STAN, Eugen I. SCARLAT

By superpositio of episodes of Gaussian noise over the “chaos game time series” (approximated by the Chinese Yuan/USD series) we reconstruct changes of exchange rates of 10 national currencies with respect to the US Dollar during 1996-2006. By subsequent integration, a reconstruction of the real series is obtained. The…

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13

NOISE INFLUENCE ON FRACTAL DIMENSION IN THE PROCESS OF GENERATION OF THE JULIA FRACTALS

Constantin ROªU, Doina M. MAXIMEAN

Fractals are encountered in nature in many domains. One of their main characteristics is the fractional geometric dimension. As opposed to deterministic fractals in which the self- similarity can be explored at any scale, in real systems this is limited by the presence of noise, that influences the fractal dimensions. …

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14

DECISION SUPPORT SYSTEMS AND NUCLEAR EMERGENCY EXERCISES – HYDROLOGICAL IMPACT ASSESSMENT

Elena SLAVNICU, Dan SLAVNICU, Dorina GHEORGHIU

The paper presents several aspects relevant in the decision support for management of radiological emergency The two assessment toolkits are used – RODOS (HDM – module) and MOIRA for evaluation of radiological impact in hydrological network. Some results concerning the assessment of radionuclide concentration in water …

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15

EXISTENCE OF THE SOLUTIONS OF FORCED PENDULUM EQUATION BY VARIATIONAL METHODS

Irina MEGHEA, Victoria STANCIU

A result of variational calculus is taken and presented in an improved form both of the statement and proof. Together with other two classical results, the announced theorem is used to demonstrate a statement which characterizes the existence of at least two T-periodic solutions which not differ by a multiple of 2 in …

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16

A STABILITY STUDY OF NON-NEWTONIAN FLUID FLOWS

Corina CIPU, Carmen PRICINÃ, Victor ÞIGOIU

The problem of the flow of a generalized Oldroyd –B fluid between two parallel plates is studied. We are interested if a von Karman type solutions are admissible for this fluid. We precise a frame of the problem from the point of stability view. We discuss some restrictions by certain inequality upon constitutive par…

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