共查询到20条相似文献,搜索用时 46 毫秒
1.
D. Bernardi V. Colombo G.G.M. Coppa A. D'Angola 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):337-348
The paper deals with the time-dependent numerical simulation of inductively-coupled plasma torches during the ignition transient,
which is induced by a graphite rod and leads to the final, self-sustaining plasma condition. The study has been performed
by using a 2D time-dependent fluid-magnetic code based on the SIMPLER algorithm within the assumptions of laminar flow, local
thermodynamic equilibrium conditions and optically thin plasma. The graphite rod has been treated as a real obstacle for the
gas and the electron emission due to the thermoionic effect has been suitably taken into account. The advantage of using a
time-dependent code in order to select different plasma operating conditions that can lead to stable discharges is pointed
out. Results for both argon and air discharges are presented for different torch geometries, RF frequencies and inlet gas
configurations (also including the presence of a carrier gas injected along the axis of the torch). Moreover, the final self-sustaining
plasma configurations obtained are compared, when available, with results coming from static models, which have been published
by other authors.
Received 29 December 2000 相似文献
2.
A.L. Balandin Y. Ono T. Tawara 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):97-103
A novel three-dimensional (3-D) tomography software has been developed for spherical tokamak (ST) plasmas with thin central
coils. It enables us to measure whole 3-D annular profiles of ST plasma emissivity (line spectrum etc.) using limited number
of detectors located on a sphere outside of its separatrix. The numbers and positions of detectors have been optimized for
STs that contain low-n toroidal modes from n = 1 to 5. Mathematical method allowing for the removal of the thin central coil from the region of reconstruction and to
reconstruct STs with single and double axes are also discussed. The shadow effect of center coil region was found to limit
the reconstruction accuracy, indicating that the low-aspect ratio torus (ST) is essential to this new 3-D tomography diagnostics.
Received 17 August 2000 and Received in final form 16 November 2000 相似文献
3.
J. A. Pomarico D. I. Iriarte H. O. Di Rocco 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):65-72
In this paper we analyze the variations in line intensities ratios due to a non-equilibrium situation and to optical depth
effects. A four level model is proposed and the two particular situations for the possible transitions are considered. Electron
density and temperature as well as the source thickness are used as independent parameters to find out in which way and extent
they modify the ratios of levels populations compared with the ideal case of an equilibrium state and optically thin source.
Accordingly with the ion of interest, electron temperatures ranging from I/20 to I/7 eV (I being the ionization energy), whereas electron densities in the interval from 1014 to 1020 cm-3 will be considered. These ranges are of special interest for diverse applications such as LIBS and measurement of transition
probabilities. Some results are presented for real ions and a new expression for the escape factor is also proposed for general
plasma conditions.
Received 12 June 2001 and Received in final form 24 October 2001 相似文献
4.
G. Montagnoli S. Beghini F. Scarlassara A.M. Stefanini L. Corradi C.J. Lin G. Pollarolo Aage Winther 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):351-356
The two systems 40Ca + 90,96Zr have been studied by measuring nucleon transfer reactions at two energies near the Coulomb barrier, thus complementing
the available sub-barrier fusion cross-sections. Angular distributions for various transfer channels have been determined.
Significantly larger neutron transfer cross-sections are found for the target 96Zr that exhibits the larger enhancement in the sub-barrier fusion cross-sections. All data have been analyzed with a new model
for heavy-ion collisions that calculates simultaneously transfer cross-sections, fusion excitation functions and barrier distributions.
The model gives a good account of both transfer and fusion data.
Received: 2 May 2002 / Accepted: 4 June 2002 / Published online: 26 November 2002
RID="a"
ID="a"e-mail: montagnoli@pd.infn.it, Fax +39049 8277102, Tel. +39049 8277117.
RID="b"
ID="b"On leave from the China Institute for Atomic Energy, 102413 Beijing, China.
Communicated by C. Signorini 相似文献
5.
E. Mergel C.M. Petrache G. Lo Bianco H. Hübel J. Domscheit D. Roßbach G. Schönwaßer N. Nenoff A. Neußer A. Görgen F. Becker E. Bouchez M. Houry A. Hürstel Y. Le Coz R. Lucas Ch. Theisen W. Korten A. Bracco N. Blasi F. Camera S. Leoni F. Hannachi A. Lopez-Martens M. Rejmund D. Gassmann P. Reiter P.G. Thirolf A. Astier N. Buforn M. Meyer N. Redon O. Stezowski 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):417-420
The even-even nucleus 136Nd was studied via in-beam γ-ray spectroscopy using the 16O + 125Te reaction at 100 MeV and the EUROBALL array. One new dipole band was observed. Together with a previously identified dipole
band, whose position in the level scheme is revised, the new band forms a doublet structure similar to the recently observed
chiral bands in the odd-odd neighboring nuclei. This would be the first case of a chiral doublet in an even-even nucleus.
Received: 23 May 2002 / Accepted: 30 September 2002 / Published online: 27 November 2002
RID="a"
ID="a"e-mail: costel.petrache@unicam.it
RID="b"
ID="b"Present address: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
RID="c"
ID="c"Present address: Gesellschaft für Schwerionenforschung D-64291 Darmstadt, Germany.
Communicated by C. Signorini 相似文献
6.
T. Beier H. Häffner N. Hermanspahn S. Djekic H.-J. Kluge W. Quint S. Stahl T. Valenzuela J. Verdú G. Werth 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):41-44
We describe a double-Penning-trap experiment suitable for testing QED in strong fields by determining the electronic g-factor of a single hydrogen-like ion in its ground state. Our measurements on 12C5 + reach a relative accuracy of 2×10-9, where the largest uncertainty results from the mass of the electron. Together with equally precise theoretical predictions
therefore, it is possible to evaluate a new value for the electron's mass. The possibilities to obtain other fundamental constants
and nuclear parameters are lined out.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: t.beier@gsi.de 相似文献
7.
8.
C.M. Petrache G. Lo Bianco P.G. Bizzeti A.M. Bizzeti-Sona D. Bazzacco S. Lunardi M. Nespolo G. de Angelis D.R. Napoli N. Blasi S. Brant D. Vretenar 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):337-346
The even-even nucleus 126Ce was studied via in-beam γ-ray spectroscopy using the 40Ca + 92Mo reaction at 190 MeV. Five bands were observed, one of them being identified for the first time. New connecting transitions
were identified between the bands, which lead to new spin assignments. The bands are discussed in the framework of the IBM
+ broken pairs model.
Received: 17 July 2002 / Accepted: 23 October 2002 / Published online: 18 February 2003
RID="a"
ID="a"e-mail: costel.petrache@unicam.it
Communicated by C. Signorini 相似文献
9.
V.P. Zhdanov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):485-489
To illustrate complex spatio-temporal effects which are possible in cellular reactions with a small number of particles, we
present Monte Carlo simulations of the formation of oscillatory spark-like patterns in a model completely stochastic Ca+2 oscillator. Our analysis shows that in order to observe such patterns the minimum average number of Ca+2 ions in the cytosol may be as low as about 50.
Received 21 April 2002 / Received in final form 19 June 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: zhdanov@catalysis.nsk.su 相似文献
10.
Th. Desaive M. Hennenberg G. Lebon 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):641-647
In this work, we study the problem of onset of thermal convection in a rotating saturated porous medium heated from below.
The effect of rotation is restricted to the Coriolis force, neglecting thus the centrifugal effects, the porous medium is
described by Brinkman's model. The linear eigenvalue problem is solved by means of a modified Galerkin method. The behavior
of the critical temperature gradient is discussed in terms of various parameters of the system for both stationary and overstable
convections. Finally a weakly nonlinear analysis is provided to derive amplitude equations and to study the onset of Küppers-Lortz
instability.
Received 24 June 2002 / Received in final form 11 September 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: tdesaive@ulg.ac.be 相似文献
11.
N.L. Tsintsadze P.K. Shukla L. Stenflo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):109-115
The electroweak coupling between intense neutrino beams and strongly degenerate relativistic dense electron-positron magnetoplasmas
is considered. The intense neutrino bursts interact with the plasma due to the weak Fermi interaction force, and their dynamics
is governed by a kinetic equation. Our objective here is to develop a kinetic equation for a degenerate neutrino gas and to
use that equation to derive relativistic magnetohydrodynamic equations. The latter are useful for studying numerous collective
processes when intense neutrino beams nonlinearly interact with degenerate, relativistic, dense electron-positron plasmas
in strong magnetic fields. If the number densities of the plasma particles are of the order of 1033 cm-3, the pair plasma becomes ultra-relativistic, which strongly affects the potential energy of the weak Fermi interaction. The
new system of equations allows several neutrino-driven streaming instabilities involving new types of relativistic Alfvén-like
waves. The relevance of our investigation to the early universe and supernova explosions is discussed.
Received 11 September 2002 Published online 4 February 2003
RID="a"
ID="a"Permanent address: Department of Physics, Tbilisi State University, Chavchavadze 3, Tbilisi 38028, Georgia.
RID="b"
ID="b"Also at the Department of Plasma Physics, Ume? University, 90187 Ume?, Sweden; and the Center for Interdisciplinary Plasma Science,
Max-Planck Institut für Plasmaphysik und extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany. e-mail: ps@tp4.ruhr-uni-bochum.de
RID="c"
ID="c"Permanent address: Department of Plasma Physics, Ume?University, 90187 Ume?, Sweden. 相似文献
12.
V. Baru J. Haidenbauer C. Hanhart J.A. Niskanen 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):437-446
We present a new parameterization of the trinucleon wave function. As a novel feature a separable parameterization for the
complete wave function is given. In this way any calculation that considers two-body currents only is largely simplified.
To demonstrate this we calculate the π3He scattering length in chiral-perturbation theory. We find reasonable agreement with experimental values inferred from data
on level shifts in pionic 3He bound states. The relevance of the π-triton system for an alternative determination of the πN scattering lengths is discussed.
Received: 12 August 2002 / Accepted: 25 November 2002 / Published online: 25 February 2003
RID="a"
ID="a"e-mail: c.hanhart@fz.juelich.de
Communicated by V. Vento 相似文献
13.
Bo-Wen Xiao Xin Qian Bo-Qiang Ma 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):523-527
The electromagnetic form factor of the kaon meson is calculated in the light-cone formalism of the relativistic constituent
quark model. The calculated K+ form factor is consistent with almost all of the available experimental data at low-energy scale, while other properties
of the kaon could also be interrelated in this representation with reasonable parameters. Predictions of the form factors
for the charged and neutral kaons at a higher-energy scale are also given, and we find the non-zero K0 form factor at Q
2≠ 0 due to the mass difference between the strange and down quarks inside K0.
Received: 21 June 2002 / Accepted: 29 July 2002 / Published online: 3 December 2002
RID="a"
ID="a"e-mail: mabq@phy.pku.edu.cn
Communicated by A. Sch?fer 相似文献
14.
R. Lucas M.-G. Porquet Ts. Venkova I. Deloncle M. Houry Ch. Theisen A. Astier A. Bauchet S. Lalkovski G. Barreau N. Buforn T.P. Doan L. Donadille O. Dorvaux J. Durell Th. Ethvignot B.P.J. Gall D. Grimwood W. Korten Y. Le Coz M. Meyer A. Minkova A. Prévost N. Redon A. Roach N. Schulz A.G. Smith O. Stézowski B.J. Varley 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):315-323
The 115, 117, 119, 121In nuclei have been produced as fission fragments in three reactions induced by heavy ions: 12C + 238U at 90MeV bombarding energy, 18O + 208Pb reaction at 85MeV, and 31P + 176Yb at 152MeV. Their level schemes have been built from gamma-rays detected using the EUROBALL III and IV arrays. High-spin
states of 117, 119, 121In nuclei have been identified for the first time. Moreover, isomeric states lying around 2.5MeV have been established in
119, 121In from the delayed coincidences between the fission fragment detector SAPhIR and the gamma array. Most of the observed states
can be described by coupling a proton g
9/2 hole to a Sn core, while the intruder band based on an orbital from the π[g
7/2/d
5/2] sub-shells behaves as the ground-state band of neighbouring Cd isotopes.
Received: 24 May 2002 / Accepted: 11 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: porquet@csnsm.in2p3.fr
RID="b"
ID="b"Present address: CEA-DIF, DAM/DCRE/SDE/LDN, 91680 Bruyères-le-Chatel, France.
RID="c"
ID="c"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France.
RID="d"
ID="d"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France.
Communicated by D. Schwalm 相似文献
15.
R.A. Radhi 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):381-385
Coulomb form factors of C4 transitions in even-even N = Z sd-shell nuclei ( 20Ne, 24Mg, 28Si and 32S) are discussed taking into account higher-energy configurations outside the sd-shell model space which are called core polarization effects. Higher configurations are taken into account through a microscopic
theory, which allows particle-hole excitations from the 1s and 1p shells core orbits and also from the 2s1d-shell orbits to the higher allowed orbits with excitations up to 4 ω. The effect of core polarization is found essential
in both the transition strengths and momentum transfer dependence of form factors, and gives a remarkably good agreement with
the measured data with no adjustable parameters. The calculations are based on the Wildenthal interaction for the sd-shell model space and on the modified surface delta interaction (MSDI) for the core polarization effects.
Received: 24 January 2002 / Accepted: 29 July 2002 / Published online: 6 March 2003
RID="a"
ID="a"e-mail: baguniv@uruklink.net
Communicated by P. Schuck 相似文献
16.
R.-D. Herzberg N. Amzal J.E. Bastin F. Becker P.M.T. Brew P.A. Butler A.J.C. Chewter J.F.C. Cocks O. Dorvaux K. Eskola J. Gerl P.T. Greenlees N.J. Hammond K. Hauschild K. Helariutta F. Heßberger M. Houry A. Hürstel R.D. Humphreys G.D. Jones P.M. Jones R. Julin S. Juutinen H. Kankaanpää H. Kettunen T.L. Khoo W. Korten P. Kuusiniemi Y. Le Coz M. Leino A.P. Leppänen C.J. Lister R. Lucas M. Muikku P. Nieminen R.D. Page T. Page P. Rahkila P. Reiter Ch. Schlegel C. Scholey G. Sletten O. Stezowski Ch. Theisen W.H. Trzaska J. Uusitalo H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):205-208
In-beam conversion electron spectroscopy experiments have been performed on the transfermium nuclei 253, 254No using the conversion electron spectrometer SACRED in nearly collinear geometry in conjunction with the gas-filled separator
RITU at the University of Jyv?skyl?. The experimental setup is discussed and the spectra are compared to Monte Carlo simulations.
The implications for the ground-state configuration of 253No are discussed.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: rdh@ns.ph.liv.ac.uk
RID="b"
ID="b"Present address: GANIL, F-14021 Caen, France.
RID="c"
ID="c"Permanent address: IReS Strasbourg, IN2P3-CNRS, F-67037-Strasbourg, France.
RID="d"
ID="d"Present address: CEA/DIF DCRE/SDE/LDN F-91680 Bruyeres-le-Chatel.
RID="e"
ID="e"Present address: Daresbury Laboratory, Daresbury WA4 4AD, UK.
RID="f"
ID="f"Permanent address: IPN Lyon, IN2P3-CNRS, F-69037 Lyon, France. 相似文献
17.
M. Modarres H.R. Moshfegh A. Sepahvand 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):159-166
The free energy of the homogeneous electron fluid at finite temperature is obtained using the lowest order constrained variational
(LOCV) method. In order to test the convergence of cluster expansion series the three-body cluster terms are calculated with
the LOCV correlation functions. The results agree reasonably with those of Monte Carlo, coupled-cluster, perturbational expansion
etc, techniques at zero temperature. The flashing and critical temperatures as well as the critical exponent are found to
be about 0.6, 1.3 eV and 0.384 respectively. A similar liquid-gas phase transition to that of nuclear matter and liquid He3 is observed.
Received 15 April 2002 / Received in final form 19 October 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: modarres@khayam.ut.ac.ir 相似文献
18.
A. Neußer H. Hübel G.B. Hagemann S. Bhattacharya P. Bringel D. Curien O. Dorvaux J. Domscheit F. Hannachi D.R. Jensen A. Lopez-Martens E. Mergel N. Nenoff A.K. Singh 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):439-441
First evidence is presented for triaxial superdeformation in 170Hf. High-spin states in this nucleus have been investigated in a γ-ray coincidence measurement using the EUROBALL spectrometer
array. A new band was discovered which has moments of inertia that are very similar to the ones of triaxial superdeformed
bands in neighbouring Hf and Lu nuclei. The intensities with which these bands are populated are different from what may be
expected from calculated potential-energy minima.
Received: 11 September 2002 / Accepted: 15 October 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: neusser@iskp.uni-bonn.de
Communicated by D. Schwalm 相似文献
19.
H. Mahmud C.N. Davids P.J. Woods T. Davinson A. Heinz J.J. Ressler K. Schmidt D. Seweryniak J. Shergur A.A. Sonzogni W.B. Walters 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):85-87
78Kr beams were used to bombard 58Ni, 92Mo and 96Ru, producing three new, odd-odd, proton-emitting isotopes, 130Eu, 164mIr and 170Au. Preliminary experimental and theoretical results will be presented in this paper.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: mahmud@ph.ed.ac.uk 相似文献
20.
���𱦣������£����� 《核聚变与等离子体物理》2006,38(4):473-481
In order to optimize the process of plasma spheroidization of the lithium micro-powder, a 2-D model of inductively coupled thermal plasma torch is presented. The calculating domain of the electromagnetic field is extended to the air region outside the plasma discharge region and multi-physics coupling calculation was performed by using COMSOL software. The plasma electromagnetic field, temperature and velocity distributions are obtained. The physical mechanism of distributions is analyzed. The simulation found that there are two sets of symmetrical reflux vortices in the coil section of the plasma region. The velocity distribution which locates in the center of coil section and closes to the wall of confinement tube is in disorder. The plasma particles hit the wall along the radial direction. Disorderly flow may cause a rupture area along the circular tube wall. Based on the simulation results, it is proposed that in the process of inductively coupled plasma spheroidization, powder injection port can be moved down to avoid the upper reflux vortex. 相似文献