3,409 research outputs found
Ultra-hard fluid and scalar field in the Kerr-Newman metric
An analytic solution for the accretion of ultra-hard perfect fluid onto a
moving Kerr-Newman black hole is found. This solution is a generalization of
the previously known solution by Petrich, Shapiro and Teukolsky for a Kerr
black hole. Our solution is not applicable for an extreme black hole due to
violation of the test fluid approximation. We also present a stationary
solution for a massless scalar field in the metric of a Kerr-Newman naked
singularity.Comment: 9 pages, 3 figures, revtex4; v2: presentation improved, figures
added, matches published versio
Adatom incorporation and step crossing at the edges of 2D nanoislands
Adatom incorporation into the ``faceted'' steps bordering the 2D nanoislands
is analyzed. The step permeability and incorporation coefficients are derived
for some typical growth situations. It is shown that the step consisting of
equivalent straight segments can be permeable even in the case of fast egde
migration if there exist factors delaying creation of new kinks. The step
consisting of alternating rough and straight segments may be permeable if there
is no adatom transport between neighboring segments through the corner
diffusion.Comment: 3 pages, one figur
Morphological Instability of Steps During Crystal Growth from Solution Flow
It is shown that step moving to meet solution flow can be unstable against
lateral perturbations. The instability of long-wavelength perturbations occurs
at values of the solution flow intensity less than some critical value
depending on the step velocity. At given intensity of the solution flow, the
instability comes at the step velocity exceeding a critical velocity. Decay of
short-wavelength fluctuations is conditioned by the line tension of the step.
The step moving along the solution flow is laterally stable at all values of
the step velocity and the intensity of the solution flow. The overlapping
diffusion field of the neighbour steps suppresses the lateral instability but
it gives an instability of the step train against doubling of the period, i.e.
neighbouring steps are attracted. The equidistant train moving to meet the
solution flow is stable against the period variations.Comment: 22 pages, REVTEX (will be appeared in Journal of Crystal Growth
Stages of steady diffusion growth of a gas bubble in strongly supersaturated gas-liquid solution
Gas bubble growth as a result of diffusion flux of dissolved gas molecules
from the surrounding supersaturated solution to the bubble surface is studied.
The condition of the flux steadiness is revealed. A limitation from below on
the bubble radius is considered. Its fulfillment guarantees the smallness of
fluctuation influence on bubble growth and irreversibility of this process.
Under the conditions of steadiness of diffusion flux three stages of bubble
growth are marked out. With account for Laplace forces in the bubble intervals
of bubble size change and time intervals of these stages are found. The trend
of the third stage towards the self-similar regime of the bubble growth, when
Laplace forces in the bubble are completely neglected, is described
analytically.Comment: 22 page
Possible types of the evolution of vacuum shells around the de Sitter space
All possible evolution scenarios of a thin vacuum shell surrounding the
spherically symmetric de Sitter space have been determined and the
corresponding global geometries have been constructed. Such configurations can
appear at the final stage of the cosmological phase transition, when isolated
regions (islands) of the old vacuum remain. The islands of the old vacuum are
absorbed by the new vacuum, expand unlimitedly, or form black holes and
wormholes depending on the sizes of the islands as well as on the density and
velocity of the shells surrounding the islands.Comment: 3 pages, 1 figur
Optimization of the extent of surgical treatment in patients with stage I in cervical cancer
The study included 26 patients with FIGO stage Ia1–Ib1 cervical cancer who underwent fertility-sparing surgery (transabdominaltrachelectomy). To visualize sentinel lymph nodes, lymphoscintigraphy with injection of 99mTc-labelled nanocolloid was performed the day before surgery. Intraoperative identification of sentinel lymph nodes using hand-held gamma probe was carried out to determine the radioactive counts over the draining lymph node basin. The sentinel lymph node detection in cervical cancer patients contributes to the accurate clinical assessment of the pelvic lymph node status, precise staging of the disease and tailoring of surgical treatment to individual patient
Influence of hydrogen on mechanical properties of [012]-crystals of austenitic steel Fe-18Cr-14Ni-2Mo
The influence of hydrogen alloying on critical shear stress, strain hardening coefficient and crystal plasticity depending on temperature of testing in the range of 77...400 К and hydrogen atom concentration has been investigated on monocrystals of austenitic stainless steel Fe-18Cr-14Ni-2Mo with low staking fault energy. Hydrogenation up to 14 at. % is shown to result in 1,5...2 increase of strength properties expressed by temperature dependence of critical shearing strains and to encourage development of local deformation by sliding
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