The article raises the problem of fine tuning over-the-horizon radars with relevant information about the parameters of the ionosphere. To improve the accuracy of the radar, it is proposed to create ...a system of remote positions, which are ionosondes of vertical and inclined sensing. The results of the operation of such ionosondes serve to adjust the global model of the ionosphere. Thus, the quality of the radar is significantly improved, allowing more accurately determine the coordinates of air targets..
Typical conservative smoothed particle hydrodynamics (SPH) approximations of the gradient of a scalar field introduce two errors: one (smoothing error) is due to smoothing of the gradient by an ...integration associated with a kernel function; the other (integration error) is due to approximating the integration by summation over all particles within the kernel support. When particles are not on a uniform grid, the integration error leads to violation of zero-order consistency, i.e. the inability to reproduce a constant field. In this paper we confirm that partition of unity is the condition under which the conservative SPH approximation achieves both consistence and convergence. We show that this condition can be achieved by relaxing a particle distribution under a constant pressure field and invariant particle volume. The resulting particle distribution is very similar to that is typical for liquid molecules. We further show that with two different typical kernel functions the SPH approximation, upon satisfying the partition of unity property, is able to achieve very high-order of the integration error, which previously could be shown only with particles on a uniform grid. The background pressure used in a weakly compressible SPH simulation implies a self-relaxation mechanism, which explains that convergence with respect to increasing particle numbers could be obtained in SPH simulations, although not predicted by previous numerical analysis. Furthermore, by relating the integration error to the background pressure, we explain why the previously proposed transport-velocity formulation of SPH (S. Adami et al. (2013) 1) is able to achieve unprecedented accuracy and stability.
Using a novel method of isochronous mass spectrometry, the masses of ^{62}Ge, ^{64}As, ^{66}Se, and ^{70}Kr are measured for the first time, and the masses of ^{58}Zn, ^{61}Ga, ^{63}Ge, ^{65}As, ...^{67}Se, ^{71}Kr, and ^{75}Sr are redetermined with improved accuracy. The new masses allow us to derive residual proton-neutron interactions (δV_{pn}) in the N=Z nuclei, which are found to decrease (increase) with increasing mass A for even-even (odd-odd) nuclei beyond Z=28. This bifurcation of δV_{pn} cannot be reproduced by the available mass models, nor is it consistent with expectations of a pseudo-SU(4) symmetry restoration in the fp shell. We performed ab initio calculations with a chiral three-nucleon force (3NF) included, which indicate the enhancement of the T=1 pn pairing over the T=0 pn pairing in this mass region, leading to the opposite evolving trends of δV_{pn} in even-even and odd-odd nuclei.
A new approach to the analysis of the stress-strain state of adhesive joints and the transverse strength of layered composites is proposed. It consists in a combined use of finite-element and contact ...layer methods. Based on this approach, the problem of the long-term strength in normal separation of two adhesively bonded disks glued together by an epoxy resin, which was previously considered by R. A. Turusov, is solved. The nonlinear Maxwell–Gurevich equation is used as the law of adhesion creep. The model constructed by R. A. Turusov does not take into account the shear creep strains of contact layer and is based on the hypothesis of linear distribution of shear stresses across the thickness of adhesive layer and substrate. It was found that these simplifications lead to overestimated tangential stresses. By analyzing the creep law with time tending to infinity, the long-term elastic modulus and Poisson ratio of the adhesive are derived and the reliability of their values is confirmed.
Abstract
X-ray bursts are among the brightest stellar objects frequently observed in the sky by space-based telescopes. A type-I X-ray burst is understood as a violent thermonuclear explosion on the ...surface of a neutron star, accreting matter from a companion star in a binary system. The bursts are powered by a nuclear reaction sequence known as the rapid proton capture process (rp process), which involves hundreds of exotic neutron-deficient nuclides. At so-called waiting-point nuclides, the process stalls until a slower β
+
decay enables a bypass. One of the handful of rp process waiting-point nuclides is
64
Ge, which plays a decisive role in matter flow and therefore the produced X-ray flux. Here we report precision measurements of the masses of
63
Ge,
64,65
As and
66,67
Se—the relevant nuclear masses around the waiting-point
64
Ge—and use them as inputs for X-ray burst model calculations. We obtain the X-ray burst light curve to constrain the neutron-star compactness, and suggest that the distance to the X-ray burster GS 1826–24 needs to be increased by about 6.5% to match astronomical observations. The nucleosynthesis results affect the thermal structure of accreting neutron stars, which will subsequently modify the calculations of associated observables.
Let
(
Ω
,
μ
)
be a
σ
-finite measure space, and let
X
⊂
L
1
(
Ω
)
+
L
∞
(
Ω
)
be a fully symmetric space of measurable functions on
(
Ω
,
μ
)
. If
μ
(
Ω
)
=
∞
, necessary and sufficient conditions ...are given for almost uniform convergence in
X
(in Egorov’s sense) of Cesàro averages
M
n
(
T
)
(
f
)
=
1
n
∑
k
=
0
n
-
1
T
k
(
f
)
for all Dunford–Schwartz operators
T
in
L
1
(
Ω
)
+
L
∞
(
Ω
)
and any
f
∈
X
. If
(
Ω
,
μ
)
is quasi-non-atomic, it is proved that the averages
M
n
(
T
)
converge strongly in
X
for each Dunford–Schwartz operator
T
in
L
1
(
Ω
)
+
L
∞
(
Ω
)
if and only if
X
has order continuous norm and
L
1
(
Ω
)
is not contained in
X
.
The biology of the 17-1A antigen (Ep-CAM) BALZAR, M; WINTER, M. J; DE BOER, C. J ...
Journal of molecular medicine (Berlin, Germany),
10/1999, Letnik:
77, Številka:
10
Journal Article
Recenzirano
The glycoprotein recognized by the monoclonal antibody (mAb) 17-1A is present on most carcinomas, which makes it an attractive target for immunotherapy. Indeed, adjuvant treatment with mAb 17-1A did ...successfully reduce the 5 years mortality among colorectal cancer patients with minimal residual disease. Currently the antibody is approved for clinical use in Germany, and is on its way to approval in a number of other countries. New immunotherapeutic strategies targeting the 17-1A antigen are in development or even in early-phase clinical trials. Therefore, a better understanding of the biology of the 17-1A antigen may result in improved strategies for the treatment and diagnosis of human carcinomas. In this review the properties of the 17-1A antigen are discussed concerning tumor biology and the function of the molecule. This 40-kDa glycoprotein functions as an Epithelial Cell Adhesion Molecule, therefore the name Ep-CAM was suggested. Ep-CAM mediates Ca2+-independent homotypic cell-cell adhesions. Formation of Ep-CAM-mediated adhesions has a negative regulatory effect on adhesions mediated by classic cadherins, which may have strong effects on the differentiation and growth of epithelial cells. Indeed, in vivo expression of Ep-CAM is related to increased epithelial proliferation and negatively correlates with cell differentiation. A regulatory function of Ep-CAM in the morphogenesis of epithelial tissue has been demonstrated for a number of tissues, in particular pancreas and mammary gland. The function of Ep-CAM should be taken into consideration when developing new therapeutic approaches targeting this molecule.
Isochronicity correction in the CR storage ring Litvinov, S.; Toprek, D.; Weick, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2013, Letnik:
724
Journal Article
Recenzirano
A challenge for nuclear physics is to measure masses of exotic nuclei up to the limits of nuclear existence which are characterized by low production cross-sections and short half-lives. The large ...acceptance Collector Ring (CR) 1 at FAIR 2 tuned in the isochronous ion-optical mode offers unique possibilities for measuring short-lived and very exotic nuclides. However, in a ring designed for maximal acceptance, many factors limit the resolution. One point is a limit in time resolution inversely proportional to the transverse emittance. But most of the time aberrations can be corrected and others become small for large number of turns. We show the relations of the time correction to the corresponding transverse focusing and that the main correction for large emittance corresponds directly to the chromaticity correction for transverse focusing of the beam. With the help of Monte-Carlo simulations for the full acceptance we demonstrate how to correct the revolution times so that in principle resolutions of Δm/m=10−6 can be achieved. In these calculations the influence of magnet inhomogeneities and extended fringe fields are considered and a calibration scheme also for ions with different mass-to-charge ratio is presented.
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