128 research outputs found
Guideline on therapeutic dentistry for the 5-th term
РУКОВОДСТВАСТОМАТОЛОГИЯ ЛЕЧЕБНО-ВОССТАНОВИТЕЛЬНАЯСТОМАТОЛОГИЯ ТЕРАПЕВТИЧЕСКАЯИНОСТРАННЫЕ СТУДЕНТЫУЧЕБНО-МЕТОДИЧЕСКИЕ ПОСОБИЯПособие составлено в соответствии с учебной программой для медицинских вузов по терапевтической стоматологии. Предназначено для внутреннего использования
Bremsstrahlung radiation by a tunneling particle
We study the bremsstrahlung radiation of a tunneling charged particle in a
time-dependent picture. In particular, we treat the case of bremsstrahlung
during alpha-decay, which has been suggested as a promissing tool to
investigate the problem of tunneling times. We show deviations of the numerical
results from the semiclassical estimates. A standard assumption of a preformed
particle inside the well leads to sharp high-frequency lines in the
bremsstrahlung emission. These lines correspond to "quantum beats" of the
internal part of the wavefunction during tunneling arising from the
interference of the neighboring resonances in the well.Comment: 4 pages, 4 figure
Quantum tunneling of a complex systems: effects of finite size and intrinsic structure
A simple model is considered to study the effects of finite size and internal
structure in the tunneling of bound two-body systems through a potential
barrier. It is demonstrated that these effects are able to increase the
tunneling probability. Applications may include nuclear fusion,hydrogen atom
and Cooper pair tunneling.Comment: 9 page
Updated stellar yields from Asymptotic Giant Branch models
An updated grid of stellar yields for low to intermediate-mass
thermally-pulsing Asymptotic Giant Branch (AGB) stars are presented. The models
cover a range in metallicity Z = 0.02, 0.008, 0.004, and 0.0001, and masses
between 1Msun to 6Msun. New intermediate-mass Z = 0.0001 AGB models are also
presented, along with a finer mass grid than used in previous studies. The
yields are computed using an updated reaction rate network that includes the
latest NeNa and MgAl proton capture rates, with the main result that between ~6
to 30 times less Na is produced by intermediate-mass models with hot bottom
burning. In low-mass AGB models we investigate the effect on the production of
light elements of including some partial mixing of protons into the intershell
region during the deepest extent of each third dredge-up episode. The protons
are captured by the abundant 12C to form a 13C pocket. The 13C pocket increases
the yields of 19F, 23Na, the neutron-rich Mg and Si isotopes, 60Fe, and 31P.
The increase in 31P is by factors of ~4 to 20, depending on the metallicity.
Any structural changes caused by the addition of the 13C pocket into the
He-intershell are ignored. However, the models considered are of low mass and
any such feedback is likely to be small. Further study is required to test the
accuracy of the yields from the partial-mixing models. For each mass and
metallicity, the yields are presented in a tabular form suitable for use in
galactic chemical evolution studies or for comparison to the composition of
planetary nebulae.Comment: Accepted for publication in MNRAS; 15 page
Quasi-elastic knockout of pions and kaons from nucleons by high-energy electrons and quark microscopy of "soft" meson degrees of freedom in the nucleon
Electro-production of pions and kaons at the kinematics of quasi-elastic
knockout (which is well known in the physics of atomic nucleus and corresponds
to the -pole diagram) is proposed for obtaining their momentum distribution
(MD) in various channels of virtual decay , , ,
, , and , , . It is a powerful tool
for investigation of a quark microscopic picture of the meson cloud in the
nucleon. A model of scalar () fluctuation in the non-trivial
QCD vacuum is used to calculate pion and kaon momentum distributions (MD) in
these channels.Comment: 31 pages, 11 figures, submitted to Nucl.Phys.
Modules for Experiments in Stellar Astrophysics (MESA)
Stellar physics and evolution calculations enable a broad range of research
in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a
suite of open source libraries for a wide range of applications in
computational stellar astrophysics. A newly designed 1-D stellar evolution
module, MESA star, combines many of the numerical and physics modules for
simulations of a wide range of stellar evolution scenarios ranging from
very-low mass to massive stars, including advanced evolutionary phases. MESA
star solves the fully coupled structure and composition equations
simultaneously. It uses adaptive mesh refinement and sophisticated timestep
controls, and supports shared memory parallelism based on OpenMP. Independently
usable modules provide equation of state, opacity, nuclear reaction rates, and
atmosphere boundary conditions. Each module is constructed as a separate
Fortran 95 library with its own public interface. Examples include comparisons
to other codes and show evolutionary tracks of very low mass stars, brown
dwarfs, and gas giant planets; the complete evolution of a 1 Msun star from the
pre-main sequence to a cooling white dwarf; the Solar sound speed profile; the
evolution of intermediate mass stars through the thermal pulses on the He-shell
burning AGB phase; the interior structure of slowly pulsating B Stars and Beta
Cepheids; evolutionary tracks of massive stars from the pre-main sequence to
the onset of core collapse; stars undergoing Roche lobe overflow; and accretion
onto a neutron star. Instructions for downloading and installing MESA can be
found on the project web site (http://mesa.sourceforge.net/).Comment: 110 pages, 39 figures; submitted to ApJS; visit the MESA website at
http://mesa.sourceforge.ne
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