201 research outputs found
Vector Area Theorem mapping in crystals and polarization stability of SIT-solitons
The stability of polarization, areas, and number of self-induced transparency
(SIT)-solitons at the output from the LaF_3:Pr^{3+} crystal is theoretically
studied versus the polarization direction and the area of the input linearly
polarized laser pulse. For this purpose the Vector Area Theorem is rederived
and two-dimensional Vector Area Theorem map is obtained. The map is governed by
the crystal symmetry and takes into account directions of the dipole matrix
element vectors of the different site subgroups of optically excited ions. The
Vector Area Theorem mapping of the time evolution of the laser pulse allows one
to highlight soliton polarization properties.Comment: 3 pages, 3 figures; v2: minor corrected labels in Fig. 3 and its
cuptur
Current-induced phase transition in ballistic Ni nanocontacts
Local phase transition from ferromagnetic to paramagnetic state in the region
of the ballistic Ni nanocontacts (NCs) has been experimentally observed. We
found that contact size reduction leads to an increase in the bias voltage at
which the local phase transition occurs. Presented theoretical interpretation
of this phenomena takes into the account the specificity of the local heating
of the ballistic NC and describes the electron's energy relaxation dependences
on the applied voltage. The experimental data are in good qualitative and
quantitative agreement with the theory proposed.Comment: 8 pages, 2 figure
Ballistic and Diffuse Electron Transport in Nanocontacts of Magnetics
The transition from the ballistic electron transport to the diffuse one is
experimentally observed in the study of the magnetic phase transition in Ni
nanocontacts with different sizes. It is shown that the voltage needed
for Joule heating of the near-contact region to the critical temperature does
not depend on the contact size only in the diffuse mode. For the ballistic
contact it increases with decrease in the nanocontact size. The reduction of
the transport electron mean free path due to heating of NCs may result in
change of the electron transport mode from ballistic to diffusive one.Comment: 7 pages, 2 figures accepted for the publication in JETPL
(http://www.jetpletters.ac.ru). Will be published on 25 april 201
An observation of the meson in the system in the Pion- Interaction at Momentum of 29 GeV
The charge-exchange reaction ,
, is studied with
the upgraded VES facility (U-70, Protvino) in the interaction of a 29 GeV pion
beam with a beryllium target. The distribution over the invariant mass of the
system shows a near-threshold signal. A partial wave analysis
reveals that the scalar state () dominates in this mass region.
The observed signal can be described with a contribution of the known
resonance . Using OPE approximation for the reaction the product of branching fractions is found to be:
КОМПЛЕКСНОЕ ЛЕЧЕНИЕ БОЛЬНЫХ МЕСТНОРАСПРОСТРАНЕНЫМ РАКОМ МОЛОЧНОЙ ЖЕЛЕЗЫ С ПРОВЕДЕНИЕМ НЕЙТРОНОЙ ТЕРАПИ НА ПОСЛЕОПЕРАЦИОННЫЙ РУБЕЦ
From 2007 to 2011, 39 patients with locally advanced breast cancer (T2-4N0-3M0-1) received multimodality treatment including neo-and adjuvant chemotherapy, radical or segmented mastectomy, neutron therapy to the area of postoperative cicatrix and external beam radiotherapy to the areas of regional spread. Neutron therapy delivered to the area of postoperative cicatrix was well tolerated by all patients. The overall 4-year and relapse-free survival rates were 86,2 ± 6,8 % and 92,7 ± 4,9 %, respectivelyВ исследование включено 39 больных местнораспространенным раком молочной железы T2-4N0-3M0-1, в период с 2007 по 2011 г. получивших комплексное лечение с использованием нео- и адъювантной химиотерапии, радикальной или санационной мастэктомии, нейтронной терапии на область послеоперационного рубца и дистанционной лучевой терапии на зоны регионарного лимфоттока. Переносимость нейтронной терапии на область послеоперационного рубца у всех 39 больных РМЖ была удовлетворительной. Показатели 4-летней общей и безрецидивной выживаемости составили – 86,2 ± 6,8 % и 92,7 ± 4,9 % соответственно
Determination of the Dalitz plot parameter alpha for the decay eta->3pi^0 with the Crystal Ball at MAMI-B
A precise measurement of the Dalitz plot parameter, alpha, for the eta->3pi^0
decay is presented. The experiment was performed with the Crystal Ball and TAPS
large acceptance photon detectors at the tagged photon beam facility of the
MAMI-B electron accelerator in Mainz. High statistics of 1.8*10^6 eta->3pi^0
events were obtained, giving the result alpha = -0.032 +/- 0.002(stat) +/-
0.002(syst).Comment: 9 pages, 6 figures, published in the online-first section of EPJ A,
included changes referees asked for, added DO
Neutron skin of Pb from Coherent Pion Photoproduction
Information on the size and shape of the neutron skin on Pb has been
extracted from coherent pion photoproduction cross sections measured using the
Crystal Ball together with the Glasgow tagger at the MAMI electron beam
facility. On exploitation of an interpolated fit of a theoretical model to the
measured cross sections the half-height radius and diffuseness of the neutron
distribution are found to be 6.70 fm and 0.55 fm respectively, corresponding to a neutron
skin thickness =0.15 fm.
The results give the first successful extraction of a neutron skin with an
electromagnetic probe and indicate the skin of Pb has a halo character.
The measurement provides valuable new constraints on both the structure of
nuclei and the equation of state for neutron-rich matter.Comment: 4 figures 5 pages. Version submitted to journal. Includes additional
studies of systematic effects in the extracted diffuseness, which led to a
small increase in the quoted systematic error. These additional studies are
discussed in the revised manuscript. Also includes minor editorial
improvements to the tex
Measurement of the transverse target and beam-target asymmetries in meson photoproduction at MAMI
We present new data for the transverse target asymmetry T and the very first
data for the beam-target asymmetry F in the
reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained
with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility
of the Mainz Microtron MAMI. All existing model predictions fail to reproduce
the new data indicating a significant impact on our understanding of the
underlying dynamics of meson photoproduction. The peculiar nodal
structure observed in existing T data close to threshold is not confirmed.Comment: 5 pages, 3 figures, accepted for publication in PR
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