38 research outputs found
The effect of atomic electrons on nuclear fission
We calculate correction to the nuclear fission barrier produced by the atomic
electrons. The result presented in analytical form is convenient to use in
future nuclear calculations. The atomic electrons have a small stabilizing
effect on nuclei, increasing lifetime in nuclear fission channel. This effect
gives a new instrument to study the fission process.Comment: 4 pages, 1 figur
Calibration of <i>Herschel</i> SPIRE FTS observations at different spectral resolutions
The SPIRE Fourier Transform Spectrometer on-board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing demonstrates that the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions using housekeeping data from the instrument subsystems, the calibration cannot be corrected analytically. Therefore, an empirical correction for LR spectra has been developed, which removes the systematic noise introduced by the variation of the response functions
Laser-induced nonresonant nuclear excitation in muonic atoms
Coherent nuclear excitation in strongly laser-driven muonic atoms is
calculated. The nuclear transition is caused by the time-dependent Coulomb
field of the oscillating charge density of the bound muon. A closed-form
analytical expression for electric multipole transitions is derived and applied
to various isotopes; the excitation probabilities are in general very small. We
compare the process with other nuclear excitation mechanisms through coupling
with atomic shells and discuss the prospects to observe it in experiment.Comment: 7 pages, 5 figure
LEGEND-1000 Preconceptual Design Report
We propose the construction of LEGEND-1000, the ton-scale Large Enriched Germanium Experiment for Neutrinoless Decay. This international experiment is designed to answer one of the highest priority questions in fundamental physics. It consists of 1000 kg of Ge detectors enriched to more than 90% in the Ge isotope operated in a liquid argon active shield at a deep underground laboratory. By combining the lowest background levels with the best energy resolution in the field, LEGEND-1000 will perform a quasi-background-free search and can make an unambiguous discovery of neutrinoless double-beta decay with just a handful of counts at the decay value. The experiment is designed to probe this decay with a 99.7%-CL discovery sensitivity in the Ge half-life of years, corresponding to an effective Majorana mass upper limit in the range of 9-21 meV, to cover the inverted-ordering neutrino mass scale with 10 yr of live time
Anterolateral Thigh Perforator Flaps in Head and Neck Reconstruction
Microsurgical free tissue transfer has revolutionized head and neck reconstruction. It allows functions and esthetics to be preserved without compromising the principles of oncologic surgery. To this end, the anterolateral thigh (ALT) flap has recently gained increasing popularity. This article reviews the advantages of the ALT flap, its anatomy, and various methods of its elevation. We have successfully utilized the ALT flap for reconstructing a wide range of complex head and neck defects; a selection of our methods are outlined herein. Additionally, various configurations of the ALT flap, including the elevation of two independent cutaneous flaps from the same pedical, chimeric, and flow-through flaps, are described. The unique anatomy of the thigh allows unparalleled flexibility in flap design, useful for reconstructing defects of the tongue, buccal region, mandible, midface, scalp, and through-and-through defects of the cheek. Resultant donor site morbidity is low in comparison to other flaps that are commonly utilized for head and neck reconstruction.This article is freely available via Open Access. Click on the Additional Link above to access the full-text via the publisher's site
Dimensionality-Dependent Electrochemical Kinetics at the Single-Layer Graphene–Electrolyte Interface
The
theories to describe the rate at which electrochemical reactions
proceed, to date, do not consider explicitly the dimensionality or
the discreteness and occupancy of the energy levels of the electrodes.
We show experimentally that such quantum mechanical aspects are important
for dimensionally confined nanostructured materials and yield unusual
variation of the kinetic rate constants with applied voltage in single-layer
graphene. The observed divergence from conventional electrokinetics
was ascribed to the linear energy dispersion as well as a nonzero
density of states at the Dirac point in the graphene. The obtained
results justify the use of density of states-based rate constants
and considerably add to Marcus–Hush–Chidsey kinetics