共查询到20条相似文献,搜索用时 15 毫秒
1.
The investigation of the widespread model of particle balance and energy transport [1–5] for calculating the ion charge state
distribution (CSD) in an electron cyclotron resonance (ECR) ion source [6] is given. The modification of this model that makes
it possible to describe the confinement and accumulation processes of highly charged ions in ECR plasma for the case of gas
mixing is more precisely discussed. The discussion of the new technique for calculating the time confinement of ions and electrons,
which is based on the Pastukhov theory [7, 8], is given: calculation of confinement times during two step minimization of
special type functionals. The preliminary results obtained with this approach have been compared with available experimental
data.
The text was submitted by the authors in English. 相似文献
2.
Yu. G. Alenitsky Yu. N. Denisov A. F. Chesnov A. A. Glazov S. V. Gurskiy G. A. Karamysheva S. A. Kostromin N. A. Morozov V. M. Romanov E. V. Samsonov N. S. Tolstoi N. L. Zaplatin 《Physics of Particles and Nuclei Letters》2008,5(7):589-592
A C10-cyclotron for radioisotope production is under construction at the Dzhelepov Laboratory of Nuclear Problem, Joint Institute
for Nuclear Research (DLNP JINR). It is a compact isochronous cyclotron for accelerating H− ions to the energy of about 10 MeV. The magnetic system, vacuum chamber and accelerating system is being built now. Results
of the calculation and forming of the cyclotron magnetic field and the study of the beam dynamics from an ion source to an
extraction system in calculated magnetic field are presented.
The text was submitted by the authors in English. 相似文献
3.
A. V. Kabashin W. Marine M. Meunier 《Applied Physics A: Materials Science & Processing》2008,93(4):1011-1014
ZnO is known as one of the best materials for the implementation of the random lasing effect, associated with mirror-less
laser emission in a simultaneously amplifying and highly scattering medium. Normally, the fabrication of this medium requires
a rather complicated procedure of deposition and thermal treatment of ZnO-based films on some specific substrates, yielding
wurtzite-orientation ZnO nanocrystals. We demonstrate a rapid synthesis of highly efficient ZnO-based random lasing spots
on a piece of Zn by employing the phenomenon of laser-induced air breakdown. Being ignited near the surface of a Zn target,
plasma of the air breakdown serves as a local reactor to locally transform its properties and thus form a film of well-packed
20–40 nm ZnO nanospheres. Exhibiting extremely high amplification and scattering, this medium is capable of generating the
random lasing effect within the exciton-based photoluminescent band. 相似文献
4.
Wen-Yang Chang Te-Hua Fang Yu-Cheng Lin 《Applied Physics A: Materials Science & Processing》2008,92(3):693-701
Physical characteristics of polyimide films, including optical, micro/nano mechanical, and thermophysical characteristics
were investigated using a photometric, a nanoindentation, and a thermomechanical analyzer for applications in flexible sensors.
Experimental results show that UV light cannot transmit into the polyimide films. The transmittances, with a maximum of about
86%, at VIS and near IR lights decrease with increasing PI film thicknesses. The mechanical characteristics were determined
using tensile, bending moment, and nanoindentation testing. The stress–strain curve approximated bilinear characteristics,
the load–unload bending moment exhibited hysteresis, and nanoindentation generated elastic energy dissipation in the loading–unloading
region. Nanoindentation showed an almost uniform hardness and a reduced Young’s modulus of about 0.181±0.03 and 3.21±0.06 GPa,
respectively, when the penetrating depth was more than about 2 μm. Thermophysical characteristics were greatly influenced
on 8.3 and 25 μm specimens due to the higher relaxation of thin PI films. The thermal expansion remained steady when the thickness
was over 50 μm. The results show that PI films have potential in flexible sensing and higher temperature fabrication. 相似文献
5.
Ts. Tsogbayar 《Physics of Particles and Nuclei Letters》2009,6(2):114-117
Asymptotic formulae of some expectation values related to the relativistic corrections in inverse powers of the internuclear
distance R for the lsσ
g
electron state of hydrogen molecular ion H2+ and the lsσ molecule-like state of antiprotonic helium atom He+
are obtained with the use of the first-order perturbation function. Using these asymptotic formulae, the relativistic correction
of order mα6 for these states in reciprocal powers of the internuclear distance R is derived to accuracy of
(R
−4).
The article is published in the original. 相似文献
6.
B. Gikal S. Dmitriev G. Gulbekian P. Apel’ V. Bashevoi S. Bogomolov O. Borisov V. Buzmakov A. Cherevatenko A. Efremov I. Ivanenko O. Ivanov N. Kazarinov M. Khabarov I. Kolesov V. Mironov A. Papash S. Patschenko V. Skuratov A. Tikhomirov N. Jazvitsky 《Physics of Particles and Nuclei Letters》2008,5(7):629-633
The cyclotron IC-100 station, based on the Laboratory of Nuclear Reactions (JINR, Dubna, Russia), provides the industrial
construction of nuclear filters. During modernization, the cyclotron was equipped with a superconducting ECR-ion source and
an axial injection system. The specialized beam channel with a two coordinate scanning system and equipment for irradiating
polymer films was installed in the implantation part of the station. High intensity heavy ion beams of Ne, Ar, Fe, Kr, Xe,
I, and W have been accelerated to 1 MeV/nucleon energy. The investigation into irradiated crystals features and irradiation
of different polymer films is provided. Also, a few thousands square meters of track films with holes in the wide range of
densities were produced. The cyclotron-based station is capable of solving different kinds of scientific and applied problems
as well.
The text was submitted by the authors in English. 相似文献
7.
D. V. Shirkov 《Physics of Particles and Nuclei Letters》2008,5(6):489-493
In quantum theory, physical amplitudes are usually presented in the form of a Feynman perturbation series in powers of coupling
constant α. However, it is known that these amplitudes are not regular functions at α = 0.
For QCD, we propose new sets of expansion parameters w
k
(α
s
) that reflect singularity at α
s
= 0 and should be used instead of powers α
s
k
. Their explicit form is motivated by the so-called Analytic Perturbation Theory. These parameters reveal saturation in a
strong coupling case at the level α
s
eff (α
s
1) = w
1(α
s
1) ∼ 0.5. They can be used for the quantitative analysis of divers low-energy amplitudes.
We argue that this new picture with non-power sets of perturbation expansion parameters, as well as the saturation feature,
is of a rather general nature.
The text was submitted by the author in English.
A preliminary version with the main results was published in [1]. 相似文献
8.
A study of the beam dynamics in the C235 (T06) cyclotron made for proton therapy is presented. Results of the computer simulations
of the particle motion in the measured magnetic field are given. A study of the resonance influence on the acceleration process
was carried out. The corresponding tolerances on the magnetic field imperfections and transverse beam parameters were defined
using these simulations.
The text was submitted by the authors in English. 相似文献
9.
10.
I. S. Guk A. N. Dovbnya S. G. Kononenko F. A. Peev A. S. Tarasenko M. van der Wiel J. I. M. Botman 《Physics of Particles and Nuclei Letters》2008,5(7):638-641
At the National Science Centre, Kharkiv Institute of Physics and Technology (NSC KIPT) the possibility of creating an installation
with a subcritical reactor driven by an electron accelerator is examined. To obtain the maximal stream of neutrons from a
neutron-producing target at a minimal density of energy emission, the electron energy should be in the range of 100–200 MeV
and the size of the target should be as large as possible. Other important requirements are beam continuity with time and
long-term stability of the accelerator parameters. The variants of using the superconducting linear accelerator on the basis
of a TESLA accelerating structure as of subcritical reactor driver are considered. The basic design parameters and characteristics
of this installation are presented.
The text was submitted by the authors in English. 相似文献
11.
The DC-350 is an isochronous cyclotron designed in the Flerov Laboratory of Nuclear Reaction (FLNR). It is intended for accelerating
ions with a mass-to-charge ratio A/Z within an interval of 5–10 and with an energy of 3–12 MeV/u at the extraction radius.
These ion beams will be used in nuclear and applied physics experiments. The paper describes the results of a 3D magnet simulation.
The cyclotron magnet and IM90 analiziting-bend magnet of the axial injection channel are studied here. The influence of correction
coils on the cyclotron magnet is calculated. All magnet fields were calculated by MERMAID 3D code [1].
The text was submitted by the authors in English. 相似文献
12.
13.
Redamy Perez-Ramos 《The European Physical Journal C - Particles and Fields》2009,62(3):541-545
The energy evolution of average multiplicities and multiplicity fluctuations in jets produced in heavy-ion collisions is investigated
from a toy QCD-inspired model. In this model, we use modified splitting functions accounting for medium-enhanced radiation
of gluons by a fast parton which propagates through the quark–gluon plasma. The leading contribution of the standard production
of soft hadrons is enhanced by a factor
while next-to-leading order (NLO) corrections are suppressed by
, where the parameter N
s
>1 accounts for the induced soft gluons in the medium. Our results for such global observables are cross-checked and compared
with their limits in the vacuum. 相似文献
14.
Albert?Mihranyan Mortadha?Muhel Maria?Str?mme 《Applied Physics A: Materials Science & Processing》2009,94(2):299-305
The dissolution process of sparingly soluble CaCO3 microparticles and how the fractal surface dimension of the particles changes during dissolution is analyzed. The particles
and the dissolution process are studied using scanning electron microscopy, X-ray diffraction, nitrogen adsorption, laser
diffraction and conductance measurements. Ball milling of the particles is shown to maintain the particle crystallinity, and
to introduce an increased fractal surface dimension in the 1–10 μm size range. Dissolution is found to increase the surface
dimension of initially smooth particles and to maintain the fractal surface roughness of milled particles. The dissolution
process increases the relative number of small particles (50 nm–1 μm) whereas the larger ones decrease in size. The solubility
of the milled fractal particles was ∼1.8 times higher than that for the initially smooth ones. The presented findings show
that developing methods for increasing the fractal surface roughness of particles should be of interest for improving the
solubility of poorly soluble drug candidates. 相似文献
15.
S. Besner A. V. Kabashin F. M. Winnik M. Meunier 《Applied Physics A: Materials Science & Processing》2008,93(4):955-959
Inorganic nanoparticles offer novel promising properties for biological sensing and imaging, as well as in therapeutics. However,
these applications are often complicated by the possible toxicity of conventional nanomaterials, arising as a result of inadequate
purification procedures of nanoparticles obtained via synthetic pathways using toxic or non-biocompatible substances. We review
novel femtosecond laser-assisted methods, which enable the preparation of metal nanomaterials in clean, biologically friendly
aqueous environment (“green” synthesis) and thus completely solve the toxicity problem. The proposed methods, including laser
ablation and fragmentation, make possible the production of stable metal colloids of extremely small size (∼2 nm) with a low
coefficient of variation (15–25%). Those nanoparticles exhibit unique surface chemistry and can be used for bio-imaging, cancer
treatment and nanoparticle-enhanced Raman spectroscopy. 相似文献
16.
D. Klabučar 《Physics of Particles and Nuclei》2008,39(7):1186-1186
17.
Larisa Dunai Guillermo Peris Fajarnes Beatriz Defez Garcia Nuria Ortigosa Araque Fernando Brusola Simon 《Acoustical Physics》2009,55(3):448-450
This paper presents several experiments on sound source localization. They are based on monaural click presented at different
interclick intervals (ICI), from 10 to 100 ms. Trains of clicks were presented to 10 healthy subjects. At short interclick
intervals the clicks were perceived as a blur of clicks having a buzzy quality. Moreover, it was proven that the accurateness
in the response improves with the increase of the length of ICI. The present results imply the usefulness of the interclick
interval in estimating the perceptual accuracy. An important benefit of this task is that this enables a careful examination
of the sound source perception threshold. This allows detecting, localizing and dividing with a high accuracy the sounds in
the environment.
The text was submitted by the authors in English. 相似文献
18.
In the Shallow Water’ 06 experiment, two L-shape arrays (ARRAY52 and ARRAY32) were deployed. The vertical line array (VLA)
components of both ARRAY52 and ARRAY32 were exactly perpendicular to the direction of sound propagation. The horizontal line
array (HLA) component of ARRAY52 was exactly perpendicular to the direction of sound propagation. The HLA component of ARRAY32
was exactly parallel to the direction of sound propagation. This configuration offered an opportunity to simultaneously analyze
the three dimensional (3-D) spatial coherences: vertical, transverse horizontal and longitudinal horizontal. When the source
and the receivers were below the thermocline, both the vertical and longitudinal horizontal coherence lengths in units of
wavelength increased with increasing range and frequency. When the source was within the thermocline, the transverse horizontal
coherence length in units of wavelength decreased with frequency and exhibited weak range dependence.
The text was submitted by the authors in English. 相似文献
19.
In the presence of space charge forces, synchrotron oscillations result in periodic modulation of the space charge tune shift,
periodic crossing of betatron resonances, and particle trapping in resonance islands. The trapping effect for one-dimensional
resonance is considered using classical perturbation theory and the “frozen core” approach to calculation of space charge
forces. The beam losses and emittance growth are analyzed for arbitrary order resonance; the numerical results are given for
the third-order resonance.
The text was submitted by the authors in English. 相似文献
20.
I. N. Izosimov V. G. Kalinnikov A. A. Solnyshkin 《Physics of Particles and Nuclei Letters》2008,5(5):427-431
A strength function for the β+/EC decay of the deformed 160g
Ho (25.6 min) nucleus has been obtained from experimental data. The fine structure of the strength function S
β(E) is analyzed. It is found to have a pronounced resonant structure for Gamow-Teller transitions. In S
β(E) with μτ = +1 the Gamow-Teller resonance has been observed to split into two components. This splitting is associated with anisotropy
of isovector density oscillation in deformed nuclei. The β+/EC strength function for first-forbidden transitions is obtained in the Coulomb (ξ) approximation. It is shown that S
β(E) for first-forbidden transitions does not have a pronounced resonant structure.
The text was submitted by the authors in English. 相似文献