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LITOSFERA ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 747-774
Author(s):  
M. G. Leonov ◽  
E. S. Przhiyalgovskii ◽  
A. K. Rybin ◽  
G. G. Shchelochkov

Research subject. The concept of morphostructure implies the presence of a relationship between the relief forms of segments of the Earth’s crust and their structural and material content. This article describes the geological ensembles of the Tien Shan orogen, the tectonic structure and modern relief of which differ in their parameters from the general morphostructural plan and which, therefore, belong to the category of morphostructural anomalies. Materials and methods. The data presented in the article were obtained in the course of field structural-geological and morphostructural study of key segments of the Tien Shan orogen, as well as an analysis of materials from previous research, including the results of geophysical sounding of the Earth’s crust and geodesical monitoring of relative modern movements of reference points on the surface.Results. The article demonstrates that, against the background of the general linear-wave morphostructure of the Tien Shan orogen, there are areas whose relief and tectonic structure do not agree with the general tectonic plan of the mountain. Wi thin the considered region, different types of morphostructural anomalies are identified and described, reflecting the speci fics of the evolution and geotectonic position of individual volumes of upper-crust rock complexes: zones of concentrated deformation and tectonic joining; centrally symmetric structures formed on the site of paleoatolls; neotectonic protrusions  of the granite basement; trans-regional zone of the Talaso-Ferghana Fault and other structures. Conclusion. The formation of morphostructural anomalies is associated with the presence of non-trivial geodynamic environments operating against the background of the tectonic regime common to the Tien Shan. The modern morphostructure of the Tien Shan is the result of interference between various geodynamic regimes and settings: a regime common to the entire territory of the orogen and particular regimes that manifest themselves sporadically and are reflected in the modern relief.


2021 ◽  
Vol 56 ◽  
pp. 61-70
Author(s):  
Ya. M. Olikh ◽  

The experimental results of amplitude effects are compared (from an ultrasonic wave deformation amplitude – a tension τUS) for electron concentration and changes of the lattice parameter on the same sample GaN/Al0.2Ga0.8N/GaN/AlN. It has been experimentally established that at ultrasonic loading (frequency 5–10 MHz, amplitude – towards 2·104 W/m2) there is a nonlinear increase in the effective electron concentration and an increase in the lattice parameter; at the same time, the mobility of electrons decreases and μН(τUS) ~ |τUS|. The energy parameters of the acoustic activation charge carriers process are calculated from the approximation of experimental amplitude changes – Еа ≈ 50 meV and γn(300 K) ≈ 2,5·10-27 m3. The amplitude dependences (increase) of the relative lattice parameter change (ΔС/С) from the tension τUS have been investigated experimentally at different frequencies. The energy of DX-center transition UDX ≈ 108 meV and the activation volume of this transition γDX ≈ 6,6·10-27 m3 are calculated from the approximation of the experimental amplitude changes. The revealed correlation of the magnitude of acoustic induced effects in different experiments allows to build a quantitative energy model of the acoustic action process based on the properties of metastable DX centers. It is shown that the acoustic induced process occurs due to the dimensional displacement of the DX-center atom (a background impurity of silicon atoms) from the non-central position to the centrally symmetric one; herewith DX-center is ionized, one goes into the d0-state. It is believed that the changes are most likely to occur near penetrating dislocations in the barrier layer Al0.2Ga0.8N – acoustic modulated oscillations of the distance between the possible positions of the donor atom lead to a decrease in the barrier to the displacement of the defect.


2021 ◽  
Vol 923 (2) ◽  
pp. L25
Author(s):  
F. Ubertosi ◽  
M. Gitti ◽  
F. Brighenti ◽  
G. Brunetti ◽  
M. McDonald ◽  
...  

Abstract We present the first results of a deep Chandra observation of the galaxy cluster RBS 797 whose previous X-ray studies revealed two pronounced X-ray cavities in the east–west (E–W) direction. Follow-up VLA radio observations of the central active galactic nucleus (AGN) uncovered different jet and lobe orientations, with radio lobes filling the E–W cavities and perpendicular jets showing emission in the north–south (N–S) direction over the same scale (≈30 kpc). With the new ∼427 ks total exposure, we report the detection of two additional, symmetric X-ray cavities in the N–S direction at nearly the same radial distance as the E–W ones. The newly discovered N–S cavities are associated with the radio emission detected at 1.4 and 4.8 GHz in archival VLA data, making RBS 797 the first galaxy cluster found to have four equidistant, centrally symmetric, radio-filled cavities. We derive the dynamical and radiative ages of the four cavities from X-ray and radio data, respectively, finding that the two outbursts are approximately coeval, with an age difference of ⪅10 Myr between the E–W and N–S cavities. We discuss two scenarios for the origin of the two perpendicular, equidistant cavity systems: either the presence of a binary AGN that is excavating coeval pairs of cavities in perpendicular directions or a fast (<10 Myr) jet reorientation event that produced subsequent, misaligned outbursts.


Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1204
Author(s):  
Aleksandr V. Lun-Fu ◽  
Alexey M. Bubenchikov ◽  
Mikhail A. Bubenchikov ◽  
Vyacheslav A. Ovchinnikov

Dynamics of charged fullerene in a surface layer of fullerite is studied under the influence of neutral or charged particles of the gas phase surrounding the fullerite material. The translational displacements of the nodes of the crystal lattice structure are determined by the equations of motion of the centers of mass of fullerenes. Central fullerene, which is described as a discrete set of sixty carbon atoms, plays a special role in the presented mathematical model. Angular oscillations and rotations of the central fullerene are described by the dynamic Euler equations. All other fullerenes have a centrally symmetric field of the potential of interaction with the surrounding atoms and molecules. In this regard, we use the hybrid discrete–continuous mathematical model with four potentials that describe the interactions between the surrounding fullerenes, smoothed fullerene and an atom, a pair of atoms, and electric charges. The results of a numerical study of influence of the Coulomb interaction on the rotational and translational motion of the C60 fullerene are presented.


Author(s):  
David Alonso-Gutiérrez ◽  
Silouanos Brazitikos

Abstract We prove several estimates for the volume, the mean width, and the value of the Wills functional of sections of convex bodies in John’s position, as well as for their polar bodies. These estimates extend some well-known results for convex bodies in John’s position to the case of lower-dimensional sections, which had mainly been studied for the cube and the regular simplex. Some estimates for centrally symmetric convex bodies in minimal surface area position are also obtained.


2021 ◽  
Vol 55 (3) ◽  
pp. 82-86
Author(s):  
Julian Pfeifle

We introduce a new method for finding a non-realizability certificate of a simplicial sphere Σ. It enables us to prove for the first time the non-realizability of a balanced 2-neighborly 3-sphere by Zheng, a family of highly neighborly centrally symmetric spheres by Novik and Zheng, and several combinatorial prismatoids introduced by Criado and Santos. The method, implemented in the polymake framework, uses integer programming to find a monomial combination of classical 3-term Plücker relations that must be positive in any realization of Σ; but since this combination should also vanish identically, the realization cannot exist. Previous approaches by Firsching, implemented using SCIP, and by Gouveia, Macchia and Wiebe, implemented using Singular and Macaulay2, are not able to process these examples.


2021 ◽  
Vol 4 (3) ◽  
pp. 541-549
Author(s):  
Isabella Novik ◽  
Hailun Zheng

2021 ◽  
Author(s):  
Alexander Braginsky

Abstract In this paper, an exponential equation of motion for gas molecules is derived for the first time. The paper shows that the Kadic-Edelen forces, written in 1983 by analogy with electrodynamics, are forces that act on the momentum of particles as on a charge. The paper considers the application of the centrally symmetric force of the tensor compensating field in gas in the active state. It is shown that the intensity tensor in the gas is diagonal, so it leads to an increase in the momentum of the gas molecules exponentially in the direction of their movement. Thus, there is an exponential change in the kinetic energy of the gas molecules in the volume where the centrally symmetric intensity tensor acts. The action of a large positive intensity tensor in the gas leads to an explosion and high-temperature plasma.


Author(s):  
Martin Winter

AbstractWe give a full classification of vertex-transitive zonotopes. We prove that a vertex-transitive zonotope is a $$\Gamma $$ Γ -permutahedron for some finite reflection group $$\Gamma \subset {{\,\mathrm{O}\,}}(\mathbb {R}^d)$$ Γ ⊂ O ( R d ) . The same holds true for zonotopes in which all vertices are on a common sphere, and all edges are of the same length. The classification of these then follows from the classification of finite reflection groups. We prove that root systems can be characterized as those centrally symmetric sets of vectors, for which all intersections with half-spaces, that contain exactly half the vectors, are congruent. We provide a further sufficient condition for a centrally symmetric set to be a root system.


2021 ◽  
Vol 21 (2) ◽  
pp. 179-185
Author(s):  
Zili Wang

Abstract The space of Euclidean cone metrics on centrically symmetric octahedra with fixed cone angles θi < 2π, with total surface area 1, has a natural hyperbolic metric, and is locally isometric to hyperbolic 3-space. The metric completion of the space is isometric to a hyperbolic ideal tetrahedron whose dihedral angles are half the cone-deficits 2π − θi.


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