2,441 research outputs found
On Properties of the Isoscalar Giant Dipole Resonance
Main properties (strength function, energy-dependent transition density,
branching ratios for direct nucleon decay) of the isoscalar giant dipole
resonance in several medium-heavy mass spherical nuclei are described within a
continuum-RPA approach, taking into account the smearing effect. All model
parameters used in the calculations are taken from independent data.
Calculation results are compared with available experimental data.Comment: 12 pages, 2 figure
The Construction of Conforming-to-shape Truss Lattice Structures via 3D Sphere Packing
Truss lattices are common in a wide variety of engineering applications, due to their high ratio of strength versus relative density. They are used both as the interior support for other structures, and as structures on their own. Using 3D sphere packing, we propose a set of methods for generating truss lattices that fill the interior of B-rep models, polygonal or (trimmed) NURBS based, of arbitrary shape. Once the packing of the spheres has been established, beams between the centers of adjacent spheres are constructed, as spline based B-rep geometry. We also demonstrate additional capabilities of our methods, including connecting the truss lattice to (a shell of) the B-rep model, as well as constructing a tensor-product trivariate volumetric representation of the truss lattice - an important step towards direct compatibility for analysis.RYC-2017-2264
Evaluation of the mean intensity of the P-odd mixing of nuclear compound states
A temperature version of the shell-optical-model approach for describing the
low-energy compound-to-compound transitions induced by external single-particle
fields is given. The approach is applied to evaluate the mean intensity of the
P-odd mixing of nuclear compound states. Unified description for the mixing and
electromagnetic transitions allows one to evaluate the mean intensity without
the use of free parameters. The valence-mechanism contribution to the mentioned
intensity is also evaluated. Calculation results are compared with the data
deduced from cross sections of relevant neutron-induced reactions.Comment: LaTeX, 10 page
Numerical studies of variable-range hopping in one-dimensional systems
Hopping transport in a one-dimensional system is studied numerically. A fast
algorithm is devised to find the lowest-resistance path at arbitrary electric
field. Probability distribution functions of individual resistances on the path
and the net resistance are calculated and fitted to compact analytic formulas.
Qualitative differences between statistics of resistance fluctuations in Ohmic
and non-Ohmic regimes are elucidated. The results are compared with prior
theoretical and experimental work on the subject.Comment: 12 pages, 12 figures. Published versio
The gamma-ray telescope Gamma-1
French and Soviet specialists have designed and built the gamma-ray telescope GAMMA-1 to detect cosmic gamma rays above 50 MeV. The sensitive area of the detector is 1400 sq cm, energy resolution is 30% at 300 MeV, and angular resolution 1.2 deg at 300 MeV (and less than 20' arc when a coded aperture mask is used). Results on calibration of the qualification model and Monte-Carlo calculations are presented
SUICIDAL IDEATION IN PSORIASIS
Background . Psoriasis has been associated with depressive disease and case reports of completed suicide. Methods . 217 consenting psoriasis patients completed the Carroll Rating Scale for Depression (CRSD), a 52-item self-rated scale, with four of the Items directly addressing wishes to be dead and suicidal ideation. The patients also self-rated the severity of their psoriasis. Results . 9.7% of patients reported a wish to be dead, and 5.5% reported active suicidal ideation at the time of the study. The death wish and suicidal ideation were associated with higher depression scores (P < 0.0001) and higher patient self-ratings of psoriasis severity (P < 0,05). Patient self-reports of psoriasis severity correlated directly with the overall depression scores (r = 0.39), P < 0.0001). Conclusions . The comorbidity between depressive symptoms, suicidal ideation, and psoriasis severity is in contrast with reports that severe depression and suicidal ideation are mainly a feature of life-threatening medical disorders such as malignancies. Our finding may have important implications in the management of psoriasis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65854/1/j.1365-4362.1993.tb02790.x.pd
Theory of traveling filaments in bistable semiconductor structures
We present a generic nonlinear model for current filamentation in
semiconductor structures with S-shaped current-voltage characteristics. The
model accounts for Joule self-heating of a current density filament. It is
shown that the self-heating leads to a bifurcation from static to traveling
filament. Filaments start to travel when increase of the lattice temperature
has negative impact on the cathode-anode transport. Since the impact ionization
rate decreases with temperature, this occurs for a wide class of semiconductor
systems whose bistability is due to the avalanche impact ionization. We develop
an analytical theory of traveling filaments which reveals the mechanism of
filament motion, find the condition for bifurcation to traveling filament, and
determine the filament velocity.Comment: 13 pages, 5 figure
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