128 research outputs found

    Guideline on therapeutic dentistry for the 5-th term

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    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

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    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

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    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

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    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

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    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 tt-pole diagram) is proposed for obtaining their momentum distribution (MD) in various channels of virtual decay NB+πN \to B+\pi, B=NB=N, Δ\Delta, NN^*, NN^{**}, and NY+KN \to Y+K, Y=ΛY=\Lambda, Σ\Sigma. It is a powerful tool for investigation of a quark microscopic picture of the meson cloud in the nucleon. A model of scalar qqˉq \bar{q} (3P0^3P_0) 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)

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    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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