Formation Of Localized Structures Research Articles

Effects of minor Si addition on structural heterogeneity and glass formation of GdDyErCoAl high-entropy bulk metallic glass

Glass-forming ability (GFA) of the Gd20Dy20Er20Co20Al20 high-entropy bulk metallic glass (HE-BMG) was improved through microalloying Si element. The critical diameter of this rare-earth-based HE-BMG increases from 1.5 to 8.5 mm with 0.5 at.% Si addition without any deterioration of magnetocaloric property. Compared with the Si-free sample, the BMG with 0.5 at.% Si addition exhibits low driving force for crystallization, strong supercooled liquid behavior and sluggish crystallization kinetics, whereas excessive Si addition leads to reverse variations. Furthermore, microalloying Si can enhance nanoscale heterogeneity of elemental distribution, and thus facilitates the formation of local crystal-like structures. The connectivity and competition between icosahedra-like clusters and crystal-like structures promote the formation of stable network structure which frustrates crystallization. As Si content is excessive, icosahedra-like cluster is consumed by the further grown crystal-like structure, leading to the destruction of network and decreasing GFA. This work not only elucidates the underlying mechanism of the GFA enhanced by microalloying, but also sheds light on improving the GFA of HE-BMGs through altering nanoscale elemental distribution and structural heterogeneity.

История Лунинецкого местного самоуправления. 1842–1939 гг. – часть 3

A local government is an association of persons of public law, based on community of interests of residents of a territory determined as units of the administrative and territorial division. It is regulated and administered by organs chosen by residents on their own territory, under control of suitable government organs within the framework of authorizations determined in state law. It acts in its own name, on its own territory and on its own responsibility. It possesses assets and budget, earnings and expenses. The author of the elaboration set the task of examining of the formation and functioning of local government structures on the example of one region and the city of today’s Belarus – Łuniniec. In compliance with the announcement from the previous number of our periodical, we give the third of history of the local government of Łuniniec province in (1842–1939) to your hands. This part presents legal bases in the basis of which functioned the local government functioned in 1927–1932, history of the local government in 1926–1933, and the bill from 23 June, 1933 concerning the issue of the partial change of structure of the local government and its influence on the activity of Łuniniec municipal organs.

Localized structures formed through domain wall locking in cavity-enhanced second-harmonic generation.

We analyze the formation of localized structures in cavity-enhanced second-harmonic generation. We focus on the phase-matched limit, and consider that fundamental and generated waves have opposite signs of group velocity dispersion. We show that these states form due to the locking of domain walls connecting two stable homogeneous states of the system, and undergo collapsed snaking. We study the impact of temporal walk-off on the stability and dynamics of these localized states.

Tectonic-sedimentary approach as a basis to study thinly bedded reservoirs with complex geological structure

The article is focused on studies of features of the formation of heterogeneous geological structures namely the "lake-type" turbidite reservoirs, with complex thin-layered structure. The study of geological features and geological and commercial characteristics of such reservoirs requires selection of effective research methods. The structural features of the turbidite complex are considered on the example of terrigenous Upper Miocene sediments of the Pannonian basin of the Republic of Serbia. Based on the results of the studies, we confirmed the relationship of the structural features of mosaic structure of the basement and deep fault systems with the complex structure of terrigenous deposits. Based on the analysis of geological and geophysical material, we proposed the use of facies and tectonic-structural analysis in the complex, as complementary procedures in the study of such deposits. To test the hypothesis of formation of strata in the turbidite system mode, a sedimentological analysis of object "X" was carried out and sedimentation conditions were determined, which led to a conclusion that the influence of tectonics dominates the sedimentation during the formation of a relatively deep epicontinental basin. In order to confirm the presence of the rotational component, a lineament analysis of the territory was performed, on the basis of which the hypothesis of the formation of local structures as a result of shear tectonic movements initiated by local protrusions of deep structures was formulated and justified. Promising areas for the next stage of additional exploration of the territory are identified, based on a comprehensive analysis of core research materials, well logging and seismic data. Further study of the northern part of the territory in accordance with the described approach will most likely contribute to the discovery of local hydrocarbon deposits.

Nonlocal Raman response in Kerr resonators: Moving temporal localized structures and bifurcation structure

A ring resonator made of a silica-based optical fiber is a paradigmatic system for the generation of dissipative localized structures or dissipative solitons. We analyze the effect of the non-instantaneous nonlinear response of the fused silica or the Raman response on the formation of localized structures. After reducing the generalized Lugiato-Lefever to a simple and generic bistable model with a nonlocal Raman effect, we investigate analytically the formation of moving temporal localized structures. This reduction is valid close to the nascent bistability regime, where the system undergoes a second-order critical point marking the onset of a hysteresis loop. The interaction between fronts allows for the stabilization of temporal localized structures. Without the Raman effect, moving temporal localized structures do not exist, as shown in M. G. Clerc, S. Coulibaly, and M. Tlidi, Phys. Rev. Res. 2, 013024 (2020). The detailed derivation of the speed and the width associated with these structures is presented. We characterize numerically in detail the bifurcation structure and stability associated with the moving temporal localized states. The numerical results of the governing equations are in close agreement with analytical predictions.

Structure, Reactivity, and Mechanical Properties of Sustainable Geopolymer Material: A Reactive Molecular Dynamics Study

Sodium aluminosilicate hydrate (NASH) gel, the primary binding phase in geopolymer, determines the mechanical properties and durability of environment-friendly construction materials. In this work, the models of NASH gel were obtained by two-step procedure: the temperature quenching method and Grand Canonical Monte Carlo water adsorption. The reactive force field molecular dynamics was utilized to investigate the structure, reactivity and mechanical performance of the NASH gel with Na/Al ratio ranging from 1 to 3. Q species, the connectivity factor, shows that the increase of sodium content in NASH gel leads to depolymerization of aluminosilicate network and more non-bridging oxygen atoms. The adsorbed water molecules dissociate near the non-bridging oxygen with high reactivity in defective aluminosilicate structure. The newly produced hydroxyls associate with the aluminate species, contributing to formation of pentahedron local structure. The sodium ions distributed in the cavity of the aluminosilicate skeleton have around 4 ~ 7 nearest neighbors. Furthermore, with increasing the amount of sodium, the molecular structure of the aluminosilicate skeleton is transformed from an integrity network to partial destroyed branch structures, which gradually decreases the stiffness and cohesive force of NASH gel characterized by the uniaxial tensile testing. During the large tensile deformation process, the reactive force field MD correlates the mechanical response with the chemical reaction pathway. The aluminosilicate skeleton is stretched broken to resist the tensile loading and the hydrolytic reaction of water molecules near the stretched Si-O and Al-O bond further accelerates the degradation of NASH gel. Hopefully, this work can shed light on material design for the high performance of sustainable geopolymer at nanoscale.

Structure and phase transformations in scandia, yttria, ytterbia and ceria-doped zirconia-based solid solutions during directional melt crystallization

(ZrO2)0.999-x(Sc2O3)х(Eu2O3)0.001 (х = 0.08–0.11) and (ZrO2)0.889(Sc2O3)0.1(R2O3)0.01 (Eu2O3)0.001 (R = Y, Yb, or Ce) crystals were grown by directional melt crystallization with direct high-frequency heating. The microstructure, phase composition and local structure of the crystals were studied using optical microscopy, X-ray diffraction, Raman scattering and optical spectroscopy. Scandia, yttria and ytterbia were shown to be distributed quite homogeneously in the crystals, and their concentrations corresponded to their contents in the charge. Ceria co-doped crystals exhibited ceria displacement in the longitudinal direction, leading to a decrease in the scandia concentration. We analysed the effect of the crystallization conditions on the formation of microstructure, crystallographic phases and local crystalline structure as a function of crystal length.Two-phase (ZrO2)0.999-x(Sc2O3)х(Eu2O3)0.001 (х = 0.08–0.11) crystals were synthesized using this method. At a Sc2O3 concentration of ≤9 mol.%, tetragonal crystals containing small local regions with cubic structures were obtained. At concentrations above Sc2O3 ≥ 10 mol.%, the crystals contained the pseudocubic (t’’ phase) and rhombohedral zirconia modifications and had an inhomogeneous phase distribution in the longitudinal direction.A study of the (ZrO2)0.889(Sc2O3)0.1(R2O3)0.01(Eu2O3)0.001 (R = Y, Yb, or Ce) crystals showed that only the yttria-doped crystals were homogeneous and had a single-phase composition that comprised only the t” phase. The microstructure of the ytterbia- and ceria-doped crystals varied in the longitudinal direction. These crystals were mixtures of rhombohedral and pseudocubic phases (t’’ phase), and the rhombohedral phase was predominant in the top and bottom portions of the crystals.We show that the experimentally observed variations in the microstructure, local structure and phase composition of the crystals were largely determined by the difference in the thermal pretreatment history of different crystal regions, which is typical of this growth method.

Retraction Note to: Numerical simulation of inertial alfven waves to study localized structures and spectral index in auroral region

In the present paper, the numerical simulation of Inertial Alfven wave (IAW) in low- $$\beta $$ plasma applicable to the auroral region at 1700 km was studied. It leads to the formation of localized structures when the nonlinearity arises due to ponderomotive effect and Joule heating. The effect of perturbation and magnitude of pump IAW, formed the localized structures of magnetic field, has been studied. The formed localized structures at different times and average spectral index scaling of power spectrum have been observed. Results obtained from simulation reveal that spectrum steepens with power law index $$\sim -3.5$$ for shorter wavelength. These localized structures could be a source of particle acceleration and heating by pump IAW in low- $$ \beta $$ plasma.

Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions.

Results of a detailed structural characterization of nominally pure and doped single crystals of scheelite, eulytin, and perovskite families obtained by melt methods were considered and analyzed. The influence of growth and post-growth annealing conditions on actual compositions of crystals is shown. The reasons for the coloration of the crystals are explained. A change in crystal symmetry due to crystal–chemical and growth reasons is considered. The use of structural analysis and X-ray absorption spectroscopy is substantiated to reveal the role of activator ions in the formation of statistical and local structures, respectively. A relationship between the distribution of activator ions over crystallographic sites and photoluminescent parameters of materials is established, which allows selecting optimal systems for the application. The combined results of studying single-crystal compounds of other classes (huntite, sillenite, whitlockite, garnet, tetragonal bronzes) allow formulating and summarizing structural effects that appeared in the systems and caused by various factors and, in many cases, due to the local environment of cations. A principal difference in the structural behavior of solid solutions and doped compounds is shown. The methodology developed for single-crystal samples of complex compositions can be recommended for the systematic structural studies of functional materials of different compositions.

СТАНОВЛЕННЯ СТРУКТУР ЗАХІДНО-УКРАЇНСЬКОЇ НАРОДНОЇ РЕСПУБЛІКИ (ЗУНР) НА ТЕРНОПІЛЛІ У 1918 Р.

The article deals with the peculiar features of the formation, legitimization and development of administrative, judicial and military structures of the West Ukrainian People’s Republic (ZUNR) in the territory of the southern and central parts of the modern Ternopil region in November – December 1918. Particular attention is paid to the characteristics of the transfer of power by the Austrian administration to the Ukrainian side in the city of Tarnopol (modern Ternopil) – this example is important because, unlike in Lviv, the city mostly managed to preserve the peaceful coexistence of Ukrainian, Polish and Jewish people during the revolutionary events. The study also examines the formation of local administrative structures and law enforcement agencies, such as the Zbarazh, Chortkiv and Berezhany counties, in the context of significant militarization of society, and the deployment of the Ukrainian‑Polish war in Eastern Galicia in 1918–1919. An analysis of the formation of the ZUNR structures in the Ternopil region, in November – December 1918, makes it possible to observe state-building processes in rural areas, at the level of counties and one of the largest cities of Galicia – Tarnopol. Thus, attention is drawn to such issues on the history of ZUNR, which are virtually absent in contemporary Ukrainian and Polish historiography. Studying the creation of administrative structures, the article examines the attitude of the local Polish and Jewish population to building a local national administrative apparatus by the Ukrainians. The cases of involvement of representatives of other peoples who inhabited the territory of Ternopil region to the power vertical of the Western Ukrainian state were emphasized.

К ВОПРОСУ О ПРИРОДЕ И МЕХАНИЗМЕ ФОРМИРОВАНИЯ ЗАЛЕЖЕЙ УГЛЕВОДОРОДОВ НА ШЕЛЬФЕ ВЬЕТНАМА

The paper presents the results of the study of main factors determining conditions of formation and distribution of oil and gas deposits within the Cenozoic sedimentary cover and Precenozoic granite basement of the Vietnam shelf. The structural and tectonic model of the Kyulong basin constructed by the authors allows to reveal the conditions of formation of regional and local structures in the sedimentary cover containing hydrocarbon deposits; mechanisms of hydrocarbon traps emergence and hollow space (collectors); genesis of hydrocarbons, including the hydrocarbons existed in the basement rocks; the possible mechanism of migration and accumulation of hydrocarbons in the basement rocks. The traps which are real or potential reservoirs of hydrocarbons in the body of a crystal socle are widely developed. The structural and tectonic processes in the basement itself resulted in the development of positive morfostructures (domes, protrusions) the cores of which are made of disintegrated (granulated) rocks of a crystalline cap. In order to reconstruct the chronothermobaric conditions of occurrence and evolution of hydrocarbon generation centers and to restore the conditions of formation and distribution patterns of oil and gas accumulations on the shelf of Vietnam, three-dimensional modeling of generation and accumulation hydrocarbon systems was performed using the basin modeling technology and PetroMod software (Schlumberger, Ltd, USA). Studies of hydrocarbon biomarkers of oil fields in the Kyulong basin, including those located in the crystalline basement have shown the similarity of biomarker parameters of oil and organic matter, which demonstrates the organic nature of the oil fields of the basement on the shelf of Vietnam

Quantum Mixmaster as a Model of the Primordial Universe

The Mixmaster solution to Einstein field equations was examined by C. Misner in an effort to better understand the dynamics of the early universe. We highlight the importance of the quantum version of this model for the early universe. This quantum version and its semi-classical portraits are yielded through affine and standard coherent state quantizations and more generally affine and Weyl–Heisenberg covariant integral quantizations. The adiabatic and vibronic approximations widely used in molecular physics can be employed to qualitatively study the dynamics of the model on both quantum and semi-classical levels. Moreover, the semi-classical approach with the exact anisotropy potential can be effective in the numerical integration of some solutions. Some promising physical features such as the singularity resolution, smooth bouncing, the excitation of anisotropic oscillations and a substantial amount of post-bounce inflation as the backreaction to the latter are pointed out. Finally, a realistic cosmological scenario based on the quantum mixmaster model, which includes the formation and evolution of local structures is outlined.

Modelling of the boundary layer disturbances by localized effect of the round membrane

The spatial development of the flat plate boundary layer disturbances by the hot-wire anemometry is experimentally investigated. Controlled disturbances were introduced into the laminar flow by means of a round membrane located on the surface of the model. The impulse motion of a round membrane leads to the formation of longitudinal localized structures and wave packets in the boundary layer. Wave packets consist of a set of straight and oblique waves, differing in their propagation characteristics. The development of wave packets downstream is consistent with the linear theory of hydrodynamic stability.

The Many Roles of Binding Cooperativity in the Control of DNA Replication

The Many Roles of Binding Cooperativity in the Control of DNA Replication

Adequate mathematical modelling by wide-sense robust control design in a thrust-vectored flight dynamics problem

The conflict between the accuracy and the complexity of the adequate mathematical modelling approximations of physical phenomena is discussed. The need of finding certain types of topological equivalency between nonlinear mathematical models as the keystone to successful study is emphasized. We formulate the control problem when the controlling functions cannot directly act on the phase variables defining a given terminal manifold as a control aim through the right-hand sides of differential equations describing a mathematical model under study. The idea of creating a hierarchical cascade of controlling attractors–mediators is introduced. It is shown how the method of the goal-oriented formation of the local topological structure of one-codimensional foliations as the basis of Poincare’s-strategy-based backstepping method can be successfully used for designing terminal control. One brings up the problem of developing the tools intended for the creation of the topologically equivalent and quantitative–deviation–tolerable simplifications of the complex original mathematical models suitable for the synthesis of the control laws that are supposed to be applied to the latter ones. The two-dimensional example is analytically investigated to explain the procedure of constructing the cascade of controlling one-codimensional attractor mediators. The essentially nonlinear five-dimensional mathematical model of the longitudinal flight dynamics of a thrust-vectored aircraft in a wing-body coordinate system with two controls, namely, the angular deflections of a movable horizontal stabilizer and a turbojet engine nozzle, is investigated. The core of the designed wide-sense robust and stable in the large-tracking control algorithm is a hierarchical cascade of controlling attractor–mediators consisting of the two one-codimensional manifolds. The results of the computer simulation are presented. The topicality in creating the general theory of nonlinear mathematical modelling, as the tools to construct and manipulate the sets of topologically equivalent models being qualitative–quantitative adequate to corresponding physical phenomena, is pointed up in conclusion.

Study of the Compression of a Condensed Deuterated Target Installed on the Wire Array Axis

The implosion of combined loads consisting of an outer wire (fiber) array and inner cylindrical target was studied experimentally at the Angara-5-1 facility (3.5 MA, 100 ns) at currents of up to 3.5 MA. The experiments were carried out with 12- and 20-mm-diameter outer arrays made of 15-μm-diameter aluminum wires, composite arrays made of aluminum wires and 25-μm-diameter kapron fibers, and arrays made of kapron fibers with a 1-μm-thick aluminum coating. The number of wires varied from 10 to 40. The targets were made of agar-agar or low-density deuterated polyethylene. The parameters of the Z-pinch plasma were determined using the Angara-5-1 diagnostic complex, which included optical streak cameras, X-ray frame cameras, X-ray detectors, X-ray pinhole cameras, neutron detectors, and a mica-crystal X-ray spectrograph. It is established that the plasma compression dynamics and the formation of local plasma structures generating neutrons depend on the load configuration: the array diameter, the number of wires (fibers), and the diameter and density of the target. The most efficient compression and the highest plasma parameters (the compression ratio and plasma temperature), as well as the highest neutron yield, were achieved in experiments with 12-mm-diameter aluminum wire arrays inside which a 1-mm-diameter deuterated target with a mass density of 0.3 g/cm3 was installed As a result of collision of the bulk of the array mass with the inner target, a compact pinch with a diameter of ≈0.5 mm forms. The pinch formation is accompanied by the generation of a soft X-ray pulse. The development of MHD instabilities in the pinch plasma results in the formation of multiple hot spots (HSs) on the pinch axis with a typical size of 200–300 μm and an electron temperature of 0.4–0.7 keV. The HS formation is accompanied by emission of neutrons with a mean energy of 2.7 ± 0.2 MeV. The maximum neutron yield achieved in these experiments was 2.6 × 1010 neutrons/shot.

Untangling the Galaxy. I. Local Structure and Star Formation History of the Milky Way

Abstract Gaia DR2 provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and (many of which have not been previously known). We estimate their ages with the precision of ∼0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings (<100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of ∼300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.

Spontaneous generation of dark-bright and dark-antidark solitons upon quenching a particle-imbalanced bosonic mixture

We unveil the dynamical formation of multiple localized structures in the form of dark-bright and dark-antidark solitary waves that emerge upon quenching a one-dimensional particle-imbalanced Bose-Bose mixture. Interspecies interaction quenches drive the system out-of-equilibrium while the so-called miscible/immiscible threshold is crossed in a two directional manner. Dark-bright entities are spontaneously generated for quenches towards the phase separated regime and dark-antidark states are formed in the reverse process. The distinct mechanisms of creation of the aforementioned states are discussed in detail and their controlled generation is showcased. In both processes, it is found that the number of solitary waves generated is larger for larger particle imbalances, a result that is enhanced for stronger postquench interspecies interactions. Additionally the confining geometry highly affects the production of both types of states with a decaying solitary wave formation occurring for tighter traps. Furthermore, in both of the aforementioned transitions, the breathing frequencies measured for the species differ significantly for highly imbalanced mixtures. Finally, the robustness of the dynamical formation of dark-bright and dark-antidark solitons is also demonstrated in quasi one-dimensional setups.

Structure of liquid Al-Ge-Ni melts in a wide composition range

X-ray diffraction study of the Al-Ge-Ni melts along different sections of the ternary phase diagram has been discussed. The measurements were taken at 1000 °C or at temperatures on 50° above liquidus for compositions with high melting point. It has been shown that AlNi interactions play the most important role in the formation of the local atomic structure in the Al-Ge-Ni melts. The most significant decreasing of the nearest interatomic distance (R1) takes places with addition of Ni to binary AlGe alloys. There is a competition between Al and Ge atoms in the formation of local atomic structure around Ni atoms. For ternary melts with high Ge content the influence of GeGe pairs increases resulting in the formation of the clusters with structure similar to the liquid germanium. The ribbons of the Al79Ge15Ni6, Al61Ge29Ni10 and Al61Ge15Ni24 alloys have been obtained by rapid solidification from the liquid state. The phase analysis of the as-quenched and annealed ribbons has been discussed.

Identification of ZnTiO3 nanostructures in oxidized TiN/ZnS thin films using X-ray absorption spectroscopy

We examined the chemical and local structural properties of oxidized TiN/ZnS and TiN/ZnO thin films using X-ray absorption spectroscopy (XAS). The composite films were oxidized by post-deposition annealing (PDA) under various oxygen partial pressures (P(O2)). The results of the X-ray absorption near-edge structure (XANES) analyses showed that the S and N vaporized, and a zinc titanate (ZnTiO3)-like phase formed when annealed under the oxygen ambiance. An ab initio XANES simulation as well as the extended X-ray absorption fine structure (EXAFS) analysis further resolved the local structures of ZnTiO3-like phase into high symmetry structures such as ilmenite-like or perovskite-like local structure; for instance, the local structure of TiN/ZnS films annealed with P(O2) = 2 Torr could be described as a mixture of 50% ilmenite ZnTiO3 + 30% perovskite ZnTiO3 + 20% wurtzite ZnO local structures. The formation of ZnTiO3-like local structure is also subject to the temperature during the PDA or the choice of bottom layers (ZnS or ZnO). The temperature of the TiN/ZnS-to-ZnTiO3 local structural phase transformation, was estimated to be 500–600 °C at P(O2) = 2 Torr, and ZnO as bottom layer apparently expedited such local structural evolution by supplying oxygen to TiN.