Electron-ion Coulomb Bremsstrahlung in nonideal plasmas

The classical electron-ion Coulomb Bremsstrahlung process is investigated in nonideal plasmas. An effective pseudopotential model taking into account the plasma screening and collective effects is applied to describe the electron-ion interaction potential in a classical nonideal plasma. The classical straight-line trajectory method is applied to the motion of the projectile electron in order to visualize the variation of the differential Bremsstrahlung radiation cross-section (DBRCS) as a function of the scaled impact parameter, nonideal plasma parameter, projectile energy, photon energy, and Debye length. The results show that the DBRCS in ideal plasmas described by the Debye-Hückel potential is always greater than that in nonideal plasmas, i.e., the collective effects reduce the DBRCS for both the soft and hard photon cases. For large impact parameters, the DBRCS for the soft photon case is found to be always greater than that for the hard photon case. Received 1st December 1999     

High-spin 52 117 Te: Rotational bands? Noncollective oblate

¹¹⁷Te has been studied via⁸²Se(⁴⁰Ar,5n)¹¹⁷Te, and a new, substantially extended level scheme is proposed to I53/2. Our TRS calculations suggest rotational bands, but with an experimental sensitivity of 2%, we see none. Our results differ from those of Sharma, et al, who report two isolated E2 bands. We find them less band-like, being joined at the top and changed in content and order. We suggest a noncollective oblate shape for a new 39/2^– level.This work is supported in part by the Department of Energy under Contract No.DE-AC03-76SF0098(LBL).     

Constructive influence of noise-flatness in correlation ratchets

The influence of noise-flatness on overdamped motion of Brownian particles in a 1D periodic system with a simple sawtooth potential subjected to both unbiased thermal noise and three-level telegraph noise is considered. The exact formula for the stationary probability flux (current) is presented. The phenomenon of multiple current reversals and some topological properties of the hypersurface of zero current in the parameter space of noises are investigated and illustrated by phase diagrams. The conditions for the existence of four current reversals versus the switching rate of nonequilibrium noise are given. An alternative interpretation of the results in terms of cross-correlation between two dichotomous noises is presented.     

Coherent control of stimulated emission inside one dimensional photonic crystals: strong coupling regime

The present paper discusses the stimulated emission, in strong coupling regime, of an atom embedded inside a one dimensional (1D) Photonic Band Gap (PBG) cavity which is pumped by two counter-propagating laser beams. Quantum electrodynamics is applied to model the atom-field interaction, by considering the atom as a two level system, the e.m. field as a superposition of normal modes, the coupling in dipole approximation, and the equations of motion in Wigner-Weisskopf and rotating wave approximations. In addition, the Quasi Normal Mode (QNM) approach for an open cavity is adopted, interpreting the local density of states (LDOS) as the local density of probability to excite one QNM of the cavity; and therefore rendering this LDOS dependent on the phase difference of the two laser beams. In this paper we demonstrate that the strong coupling regime occurs at high values of the LDOS. In accordance with the results of the literature, the emission probability of the atom decays with an oscillatory behaviour, so that the atomic emission spectrum exhibits two peaks (Rabi splitting). The novelty of this work is that the phase difference of the two laser beams can produce a coherent control of both the oscillations for the atomic emission probability and, as a consequence, of the Rabi splitting in the emission spectrum. Possible criteria to design active delay lines are finally discussed.     

Two stage electrostatic separator for the recycling of plastics from waste electrical and electronic equipment

The aim of study was to evaluate the effectiveness of a new facility for recycling of plastics from granular waste electrical and electronic equipment. The installation consists of two sections, the products of a first tribo-aero-electrostatic separator being subsequently treated in two free-fall electrostatic separators. The tests were performed on a mixture of polycarbonate (PC) and polyamide (PA). Analysis of the purity of the products obtained was performed using a program of image processing in MATLAB. Products of very high purity (roughly 95% for both PC and PA) were obtained at a recovery rate higher than 70%.     

Picosecond time-resolved nonresonant ionization detected IR spectroscopy on 7-azaindole dimer

The picosecond time-resolved IR spectrum of the 7-azaindole dimer has been measured by picosecond time-resolved nonresonant ionization detected IR spectroscopy. This new time-resolved technique was developed by combining nonresonant ionization detected IR (NID-IR) spectroscopy with tunable picosecond IR and UV lasers. The time-resolved NID-IR spectrum from 2 600 cm^-1 to 3 800 cm^-1 shows a drastic change from 1.5 ps to 11 ps time evolution. A mode-specific vibrational redistribution has been suggested. Received 14 May 2002 / Received in final form 11 June 2002 Published online 13 September 2002     

The half-life of the 1437 keV 11/2− state in97Mo

Using the (,n) reaction, the half-life of the first 11/2^– level in⁹⁷Mo has been determined as T_1/2(1437.0 keV)=2.5±0.3 ns by means of the pulsed beam method. The experimentally obtainedB(M2) value between theh _11/2 andg _7/2 configurations in⁹⁷Mo has been satisfactorily described within the quasiparticle-phonon model usingg _s ^eff =0.6g _s ^free . Similar calculations and comparisons with experminental data have been performed also for^95,99Mo as well as for⁹⁹Ru and¹⁰¹Pd.This work is partly supported by the Bulgarian National Research Foundation     

Trace anomaly and chiral symmetry breaking scale in the Nambu and Jona-Lasinio model

Bound state pion production in⁴⁰Ca and¹²⁰Sn nuclei in (p,2p) and (n,d) reactions is investigated. The differential and total cross sections have been obtained. It is shown that the cross sections are determined by the overlap function of the bound states of the nucleon and pion, and as consequence,s-wave part of the pion-nucleus optical potential. The contributions from the nucleons and deuteron distortions are evaluated.The authors would like to express their gratitude to R.A. Eramzhyan, S.N. Gninenko, V.B. Kopeliovich, V.M. Lobashev, B.B. Matveev and E. Oset for very useful and stimulating discussions.     

Investigation of the fusion reaction27Al+236U→263105 at excitation energies of 57 MeV and 65 MeV

The neutron-deficient isotopes^257,258105 were produced in the reaction²⁷Al+²³⁶u in 6n and 5n evaporation channels, respectively. The evaporation residues emerging from the target were separated in-flight from the projectiles and from products of different nuclear reactions by the electrostatic separator VASSILISSA [1]. The isotopes were then implanted into position-sensitive silicon detectors and identified using the --correlation method. The measured production cross-section is (5n)=(0.45±0.20)nb atE _P =154 MeV and (6n)=(0.075±0.055) nb atE _P =163 MeV. These cross-sections are compared with data measured for the same isotopes in the more symmetrical reaction⁵⁰Ti+²⁰⁹Bi.