Orientation Of Vector Research Articles

Polarization Dependence of Laser-Induced Dynamics on Non-Flat Metal Surfaces: A Time-Dependent Density Functional Theory Approach.

Real-time time-dependent density functional theory was used to study the laser-pulse-induced ion dynamics on metal surfaces featuring rows of atomic ridges. In contrast to atomically flat surfaces, the rows of atomic ridges induce anisotropy on the surface even in surface-parallel directions. This anisotropy causes the laser-induced ion dynamics to depend on the orientation of the laser polarization vector in the surface-parallel directions. This polarization dependence occurs for both copper (111) and aluminum (111) surfaces, indicating that the existence of localized d orbitals in the electronic system does not play a crucial role. The difference in kinetic energies between ions on the ridges and those on the planar surface reached a maximum when the laser polarization vector was perpendicular to the rows of ridges but parallel to the surface. A simple mechanism for the polarization dependence and some potential applications in laser processing are discussed.

Research for Optimal Programs for Controlling the Relative Motion of a Spacecraft with Limited Thrust

The problem of optimal control of the relative motion of a spacecraft with a finite thrust engine in arbitrary circumcircular orbits using the Pontryagin’s maximum principle is considered. Motion is studied in an orbital cylindrical coordinate system, using variables written in the form of secular and periodic components of relative motion in the orbital plane. The main attention is paid to the analysis of the optimal control structure with a free and transversal orientation of the thrust vector in the presence of passive areas on the trajectory. As a criterion for choosing the optimal control, the motor operating time of the corrective motors was considered. Characteristic control structures for various areas of initial driving conditions have been determined, and estimates of the marginal costs of motor time have been obtained.

Laser‐Induced Creation of Antiferromagnetic 180‐Degree Domains in NiO/Pt Bilayers

AbstractThe antiferromagnetic order in heterostructures of NiO/Pt thin films can be modified by optical pulses. After the irradiation with laser light, the optically induced creation of antiferromagnetic domains can be observed by imaging the created domain structure utilizing the X‐ray magnetic linear dichroism effect. The effect of different laser polarizations on the domain formation can be studied and used to identify a polarization‐independent creation of 180° domain walls and domains with 180° different Néel vector orientation. By varying the irradiation parameters, the switching mechanism can be determined to be thermally induced. This study demonstrates experimentally the possibility to optically create antiferromagnetic domains, an important step towards future functionalization of all optical switching mechanisms in antiferromagnets.

The Spatial Ventricular Gradient Is an Independent Predictor of Anthracycline-Associated Cardiotoxicity

BackgroundAnthracyclines are effective chemotherapies that are limited by cardiotoxicity. The spatial ventricular gradient (SVG) is a marker of electrical heterogeneity linked to adverse cardiovascular outcomes, including sudden cardiac death and heart failure (HF). ObjectivesThe purpose of this study was to assess if SVG values before chemotherapy are associated with the risk of anthracycline-associated HF or cardiomyopathy (CM). MethodsWe analyzed 12-lead electrocardiograms obtained within 6 months before initiation of anthracyclines in a retrospective cohort treated for cancer between 1992 and 2019 at a single academic medical center. Incident HF and CM were defined by ICD-9/10 codes and confirmed by chart review. Vectorcardiograms were constructed from baseline electrocardiograms, and the SVG was calculated. The cumulative incidence of anthracycline-associated HF or CM was regressed on SVG vector orientation and magnitude with death as a competing risk. ResultsIn 889 patients (47% male; mean age 58 ± 16 years; 71% hematologic malignancies), larger SVG magnitude prechemotherapy was associated with decreased risk of HF or CM after multivariable adjustment, with a subhazard ratio of 0.76 per 1 SD increase (95% CI: 0.59-0.96; P = 0.024). SVG vector orientation, specifically a more leftward oriented VGx, was associated with decreased risk of HF or CM with a subhazard ratio of 0.77 per 1 SD increase (95% CI: 0.61-0.96; P = 0.023). ConclusionsLarger SVG magnitude and more leftward SVG orientation were associated with a decreased risk of anthracycline cardiotoxicity in a large retrospective cohort. Improved cardiac risk stratification algorithms incorporating the SVG could personalize both cancer and cardioprotective therapy.

Neural network analysis of energy efficiency of the regional economy as a factor of Russia's sustainable development under conditions of big challenges

Subject. We consider the energy efficiency of Russia’s regional economy and its impact on sustainable development of the country in the face of big challenges. Objectives. The focus is on solving the multidimensional task of analyzing the development of energy efficiency of the economy of Russian regions, which relates to difficult-to-formalize tasks and harmonizes with modern requirements of competitiveness. Methods. We employ the cluster analysis based on neural networks, which are a relevant component of artificial intelligence. We also use the toolkit of artificial neural networks, i.e. Kohonen self-organizing maps. The said tools are free from model limitations and external interference in the functioning of the neural network, and enable to visualize the clustering results of multidimensional data space on the plane. Results. The cluster analysis of heterogeneous data enabled to distribute Russian regions across eight cluster formations. The considered indicators characterizing the energy efficiency of Russia’s regional economy had different effects on the creation of clusters. We obtained a significant unevenness of the distribution of Russian regions by cluster: the number of regions in clusters varied more than fourfold. We determined different levels of energy efficiency of the regions’ economy according to the studied indicators on cluster scale. This requires the application of different economic development strategies for regions of the Russian Federation in the focus of cluster formations. Conclusions. The paper shows the influence of big challenges on the development of energy efficiency of Russia. The findings indicate that to improve the sustainable and progressive development of Russia’s economy, innovative organizational and managerial methods are needed that generate a vector of orientation towards effective solution of urgent challenges facing the country.

Numerical simulation of periodic surface structures created by direct laser interference patterning.

Surface structuring using nano-second lasers can be used to enhance certain properties of a material or even to introduce new ones. One way to create these structures efficiently is direct laser interference patterning using different polarization vector orientations of the interfering beams. However, experimentally measuring the fabrication process of these structures is very challenging due to small length and time scales. Therefore, a numerical model is developed and presented for resolving the physical effects during formation the predicting the resolidified surface structures. This three-dimensional, compressible computational fluid dynamics model considers the gas, liquid, and solid material phase and includes various physical effects, such as heating due to the laser beam for both parallel and radial polarization vector orientations, melting, solidification, and evaporation, Marangoni convection, and volumetric expansion. The numerical results reveal a very good qualitatively and quantitatively agreement with experimental reference data. Resolidified surface structures match both in overall shape as well as crater diameter and height, respectively. Furthermore, this model gives valuable insight on different quantities during the formation of these surface structures, such as velocity and temperature. In future, this model can be used to predict surface structures based on various process input parameters.

Rotation-Angle Solution and Singularity Handling of Five-Axis Machine Tools for Dual NURBS Interpolation

Dual NURBS interpolation has been proven an essential technique for high-speed precision machining of complex surfaces. The solution of rotation angles and their derivatives is the basis of kinematic transformation and feedrate optimization in dual NURBS interpolation. The characteristics of the rotation motion of five-axis machine tools with different structures are analyzed. A generic model of dual heads of the vertical five-axis machine tool is established to unify the solution of rotation angles. Then, a generic method for solving the rotation angles and derivatives based on the vector inner product is proposed, and the solution space is analyzed. A singularity handling is given to avoid abrupt rotation angles based on the higher derivatives of the tool orientation vector. The proposed method obtained smooth rotation angles at the singularity points in the cardioid dual NURBS interpolation experiment. It reduced the machining time by 43.3% compared with the simple inverse trigonometric method based on kinematic transformation. Experiment results demonstrate that the proposed method is feasible and effective, and has significant theoretical and practical value for optimizing five-axis CNC machining.

Nonlinear Optical and Magnetic Properties of FeII-SCN-HgII Isomers: Centrosymmetric Layers and Chiral Networks

Research on isomers is highly desirable due to their prospective role in better understanding of physicochemical properties of similar systems and further development of multifunctional molecular materials. Iron(II) and tetra(thiocyanato)mercury(II) ions self-assembled in the presence of 2-acetylpyridine (2-acpy) excess to form two {[Fe(2-acpy)][Hg(μ-SCN)4]}n isomers: two-dimensional (2D) centrosymmetric layers with folded ring structural motifs (1) and three-dimensional (3D) chiral networks with right- or left-handed {···Fe-NCS-Hg-SCN···}∞ helixes (2). New methods of designing and synthesizing functional thiocyanate-bridged materials have been proposed. In addition, the similarity between 1 and 2 allowed for the description of subtle changes in IR and UV-visible spectra. Moreover, 2 shows spontaneous resolution, and it crystallizes in the noncentrosymmetric space group P21, leading to the occurrence of nonlinear optical activity in circular dichroism studies and second harmonic generation (SHG). At room temperature, the SH susceptibility for powder sample 2 reached 6.0 × 10-11 esu. Ab initio calculations indicated the electric polarization vector and the crystallographic twofold screw axis pass through the aromatic ring. Magnetic studies for 1 and 2 revealed high-spin iron(II) with zero-field splitting at low temperatures. Analysis of magnetic data gave |D| = 37.45 cm-1, |E/D| = 5.59 cm-1, and ⟨g⟩ = 2.15 for 1, |D| = 36.78 cm-1, |E/D| = 4.92 cm-1, and ⟨g⟩ = 2.18 for 2, and information about the orientation of magnetic anisotropy vectors for both compounds.

Modulating the spatial coherence-polarization from intensity basis addition of speckle patterns with polarization diversity

A technique based on an intensity basis addition of two speckle patterns with polarization diversity, which are filtered from a depolarized field, is developed to modulate the spatial coherence-polarization (CP) property of the superposed speckle pattern. It is proposed theoretically, and validated both experimentally and numerically that by tuning the polarization diversity of the constituent speckle patterns, a complete control over the spatial coherence of the superposed speckle pattern can be achieved, and the superposed speckles can be modulated from fully spatially coherent to spatially incoherent in a controlled fashion. It is also observed that if the original field is not completely depolarized, the achieved modulation of the spatial coherence not only depends on the mutual orientation of the polarization vectors of the constituent speckle patterns (as in the case of the field basis addition of speckles) but also on the sum of the polarization orientations. However, the achieved modulation is found to be similar to the case of the addition of speckle patterns in the field basis, if the original field is completely depolarized. This work may have potential application in biomedical imaging, where the intensity basis addition of speckle patterns is widely used to reduce the speckle noise.

Development of Properties Control Methods for Magnetorheological Medium to Regulate the Stiffness of Exoskeleton Variable-Length Link

Introduction. The article investigated one of the problems of creating exoskeletons — controlling the properties of magnetic rheological fluid in links of variable length with adjustable stiffness. Based on the research of domestic and foreign authors, the development and urgency of the topic was evaluated. The disadvantage of known exoskeleton models has been specified, i.e., the use of absolutely solid links, whose dynamics does not convey the dynamics of the human musculoskeletal system. The scientific research aimed at the formation of a new direction in the development of exoskeletons that accurately simulate the biomechanics of movements. Materials and Methods. Different states of structures of variable-length links with a magnetorheological fluid were studied. It has been noted that the links work on the principle of magnetic shock absorbers and consist of a piston rod, electromagnetic coils, and a housing filled with magnetorheological fluid. The ordering effect of an external magnetic field on the particles of a magnetorheological fluid was visualized and mathematically presented. The significance of such factors as time, charge density, magnetic field strength, as well as vectors of electric and magnetic induction, electric intensity and electric current density for this system was shown. The input parameter affecting the behavior of the magnetorheological fluid was determined. This was the magnetic field intensity. It was shown that the viscosity of the liquid varied depending on the shape of the magnetic particles (oblong or oblate ellipsoid). Results. The dependences that were fundamental for solving the task were investigated and visualized. The magnetic field strength and the angle between the vector directed along a straight line connecting the centers of two micron particles, and the vector of the external magnetic field strength were taken as the basic parameters. It was shown how the magnetic moment, voltage and its antisymmetric part depended on them. It was established that to control the properties of a magnetorheological fluid, it was required to change: – the external magnetic field intensity; – the angle between the external magnetic field intensity and the orientation vector between the dipoles. Two values of force were compared: one – for a given link design, and the other — fixed when walking in the lower leg of a person. The consistency of these indicators was established. Discussion and Conclusion. The scientific research results allowed us to present: – a method for controlling the properties of a magnetorheological fluid by an external magnetic field; – a variable-length link model with adjustable stiffness. The results obtained can be used in modeling multilink structures to create comfortable exoskeletons that interact synchronously with the human musculoskeletal system as a single human-machine system. The development is applicable to solving significant social and economic problems.

Orthogonal single-mode helical Bragg gratings created in fiber cladding for vector bending measurement.

We demonstrate a novel, to the best of our knowledge, two-dimensional vector bending sensor based on orthogonal helical Bragg gratings inscribed in the cladding of a conventional single-mode fiber (SMF). The helical cladding fiber Bragg gratings (HCFBGs) are created by using a femtosecond laser direct writing technology and a quarter-pitch graded index fiber (GIF) is used in front of the HCFBGs to diverge the core mode into fiber cladding. In contrast to the multimode resonance observed in conventional cladding Bragg gratings inscribed by using a femtosecond laser point-by-point (PbP) or line-by-line (LbL) technology, the proposed HCFBGs exhibit stable narrowband single-mode Bragg resonance. An HCFBG with a low peak reflectivity of -50.77 dB and a narrow bandwidth of 0.66 nm was successfully fabricated by using a lateral offset of 45 µm between the HCFBG and the fiber core axis. Moreover, two orthogonal HCFBGs were fabricated in the SMF cladding and used for vector bending sensing. Strong orientation dependence could be seen in omnidirectional bending measurement, exhibiting a maximum bending sensitivity of up to 50.0 pm/m-1, which is comparable to that in a multicore FBG. In addition, both the orientation and amplitude of bending vector could be reconstructed by using the measured Bragg wavelength shifts in two orthogonal HCFBGs. As such, the proposed HCFBGs could be used in many applications, such as structural health monitoring, robotic arms, and medical instruments.

Orientation of conduction velocity vectors on cardiac mapping surfaces.

Electroanatomical maps using automated conduction velocity (CV) algorithms are now being calculated using two-dimensional (2D) mapping tools. We studied the accuracy of mapping surface 2D CV, compared to the three-dimensional (3D) vectors, and the influence of mapping resolution in non-scarred animal and human heart models. Two models were used: a healthy porcine Langendorff model with transmural needle electrodes and a computer stimulation model of the ventricles built from an MRI-segmented, excised human heart. Local activation times (LATs) within the 3D volume of the mesh were used to calculate true 3D CVs (direction and velocity) for different pixel resolutions ranging between 500 μm and 4 mm (3D CVs). CV was also calculated for endocardial surface-only LATs (2D CV). In the experimental model, surface (2D) CV was faster on the epicardium (0.509 m/s) compared to the endocardium (0.262 m/s). In stimulation models, 2D CV significantly exceeded 3D CVs across all mapping resolutions and increased as resolution decreased. Three-dimensional and 2D left ventricle CV at 500 μm resolution increased from 429.2 ± 189.3 to 527.7 ± 253.8 mm/s (P < 0.01), respectively, with modest correlation (R = 0.64). Decreasing the resolution to 4 mm significantly increased 2D CV and weakened the correlation (R = 0.46). The majority of CV vectors were not parallel (<30°) to the mapping surface providing a potential mechanistic explanation for erroneous LAT-based CV over-estimation. Ventricular CV is overestimated when using 2D LAT-based CV calculation of the mapping surface and significantly compounded by mapping resolution. Three-dimensional electric field-based approaches are needed in mapping true CV on mapping surfaces.

ТЕОРЕТИЧНИЙ ДИСКУРС МІЖНАРОДНОЇ ТРУДОВОЇ МІГРАЦІЇ: ЕКОНОМІЧНИЙ ВИМІР

The dominant channels of globalization of the labor market, as one of the determining patterns of its modern structural transformation, are, on the one hand, the convergence of individual subsystems of national labor markets and the elimination of legal, national-ethnic, cultural-humanitarian and other barriers between them, and on the other – international labor migration. Due to its economic nature and the driving forces of development, the cross-border movement of labor resources is an extremely complex process capable of exerting a powerful transformational influence on both the scale and structure of national labor markets, as well as the demographic, professional-qualification, educational, gender, and age composition of the population of states and entire regions. It is no accident that issues related to the regulation of international labor migration processes have become an integral component of global economic policy and the adoption of various political decisions regarding interstate cooperation in recent decades. In this regard, the substantiation of the conceptual design of the global theory of labor migration based on the generalization of its theoretical arsenal and taking into account the most constructive elements of existing theories and concepts acquires significant theoretical and methodological importance. And to generalize the theoretical discourse of international labor migration processes, let us emphasize the following: each of the theories and concepts of cross-border labor movement, having its competitive advantages and methodological flaws, performed an important ontological function in the formation of scientific views on its essence, driving forces, vector orientation, organizational-economic and institutional-regulatory formats, as well as the mechanisms of the impact of migration on global employment and the functioning of national labor markets. Their key methodological principles make it possible to adequately understand the key patterns of the development of international labor migration at various stages of global economic development, to forecast their prospective trends, as well as to develop effective migration policies of states and regional groups. Despite the fact that various aspects of the classical concepts of labor migration to some extent lose their relevance in modern conditions, they are still actively used by states and regional groups to solve a wide range of strategic goals and tasks of competitive development.

Atomic force microscopy of anisotropic silicone magnetoactive composites

New anisotropic magnetically active elastomers using carbonyl iron micrometer size ferromagnetic fillers in the silicone matrix were synthesized. Samples with orientation of the outer magnetic field strength vector applied in perpendicular or in parallel direction to the mold surface during polymerizing composite mass were investigated. These composites surface structure was studied using the topography and phase contrast images in the atomic force microscope. Significant surface magnetodeformation effects in these composites, comparable with Terphenol-D, under the application of small external magnetic fields were visualized by atomic force microscopy methods. The transverse magneto-deformation constant value was determined for both samples. Greatly periodically deformed surface structure background was observed in these composites. The obtained experimental results analysis show that significant component of these materials unique properties is due to the ferromagnetic fillers restructuring in both isotropic and anisotropic magnetically active composites under small external magnetic fields influence.

THEORETICAL SUBSTANTIATION OF THE RESULTS OF MEASURING ANOMALIES OF SPACECRAFT TRAJECTORIES

It is about the solar acceleration of spacecraft. The prevailing opinion that classical properties of the fundamen¬tal laws of statics can be successfully used in the celestial mechanics of low speeds (v &lt;&lt; c) has been refuted because the involvement of relativistic methods does not improve the situation due to the smallness of the gravity mag¬netic acceleration. The essence of the problem is that the known classic methods of the theory of motion operate solely on the transverse component of the velocity vector concerning the orientation of the radius vector of the gravitational interaction. In the article, an insufficient longitudinal component was introduced into the electrogravity theory of motion, the effect of which turned out to be an order of magnitude higher than the effect of the transverse one.

SOT-MRAM Elements Based on Spin Hall Effect : Macrospin Model of Two-Step Switching Control

The article presents the results of a qualitative study of the model of a modern magnetic memory cell, in which the spin Hall effect is used for recording. Cells of square cross-section with longitudinal anisotropy of the active layer are considered. Based on the Landau-Lifshitz-Gilbert vector equation, a mathematical model for controlling the process of writing zero and one into a cell is constructed. In the approximation of a uniform distribution of magnetization, a system of equations is derived that describes the dynamics of magnetization under the action of a magnetic field and spin current. The parameters of the qualitatively equivalent dynamics of the model are determined. It has been established that at zero currents and fields in both cases there are two main stable equilibrium positions. These equilibria, depending on the mutual orientation of the magnetization vector of the active and reference layers, correspond to zero and one, written in the cell. The transition from one cell state to another is described by solving a system of differential equations. A bifurcation diagram of a dynamical system in the variables &amp;quot;field-current&amp;quot; is constructed. It is shown that with a given configuration of the memory element, external influences transfer the magnetization to an intermediate state in the plane of the free layer, which, when the current and field are turned off, leads to writing zero or one to the memory cell. The critical switching current is estimated as a function of the applied external magnetic field. Keywords: spintronics, orbitronics, magnetization, Landau-Lifshitz-Gilbert equation, spin Hall effect, spin current, charge current, spin torque, longitudinal anisotropy, planar anisotropy.

SOT-MRAM-элемент на основе спинового эффекта Холла: макроспиновая модель двухтактного переключения

The article presents the results of a qualitative study of the model of a modern magnetic memory cell, in which the spin Hall effect is used for recording. Cells of square cross-section with longitudinal anisotropy of the active layer are considered. Based on the Landau–Lifshitz–Gilbert vector equation, a mathematical model for controlling the process of writing zero and one into a cell is constructed. In the approximation of a uniform distribution of magnetization, a system of equations is derived that describes the dynamics of magnetization under the action of a magnetic field and spin current. The parameters of the qualitatively equivalent dynamics of the model are determined. It has been established that at zero currents and fields in both cases there are two main stable equilibrium positions. These equilibria, depending on the mutual orientation of the magnetization vector of the active and reference layers, correspond to zero and one, written in the cell. The transition from one cell state to another is described by solving a system of differential equations. A bifurcation diagram of a dynamical system in the variables "field-current" is constructed. It is shown that with a given configuration of the memory element, external influences transfer the magnetization to an intermediate state in the plane of the free layer, which, when the current and field are turned off, leads to writing zero or one to the memory cell. The critical switching current is estimated as a function of the applied external magnetic field. Key words: spintronics, orbitronics, magnetization, Landau – Lifshitz – Gilbert equation, spin Hall effect, spin current, charge current, spin torque, longitudinal anisotropy, planar anisotropy.

О ХАРАКТЕРЕ ЗНАЧИМОСТИ МАЛОГО И СРЕДНЕГО ПРЕДПРИНИМАТЕЛЬСТВА В ЭКОНОМИКЕ ПРОМЫШЛЕННЫХ ОТРАСЛЕЙ РОССИИ

Within the framework of the implementation of various initiatives of small and medium-sized enterprises in the field of industrial production, a clear understanding of the essential characteristics of the industrial economy and the scope of its functioning is required. In addition, it is necessary to consciously approach the objects of studying economic processes and the target orientation of the market vector. The article presents the substantial nature of the economy of the industrial sector, highlights the aspect of the importance of this branch of the economy for public administration. The dynamics of the structure of small and medium-sized enterprises (SMEs) in the period, including by districts, is demonstrated. The causal relationships of the political and economic conjuncture of Russia are noted. Conclusions about the significance and potential of SMEs are formulated for the economic growth of the country.

Hybrid InSARTrac for monitoring interglacial movement patterns

InSARTrac is a hybrid 3D monitoring method, for which controlled field measurements have indicated significant potential for geotechnical applications. Various approaches can be taken to derive 3D displacements from InSAR measurements, such as combining multiple InSAR ascending and descending satellite passes or combining multi-geometrical radar datasets from ground and satellite based radars. InSARTrac is a cost-effective solution requiring only one terrestrial InSAR device and a camera used for feature tracking. This study summarizes the results of glacial displacement measurements that were conducted to test the InSARTrac methodology. The InSARTrac 3D displacement vectors show details concerning glacial retreat dynamics related to a combination of ice flow and volume loss. By extrapolating prior results obtained from controlled field measurements, the resultant displacement vector orientations have an estimated angular error of approximately 5 degrees. With a fixed camera mount and longer monitoring times this error can be further reduced. Current studies are focused on deploying InSARTrac to investigate its potential for landslide and geostructure monitoring.

Genesis and evolution of scientific and pedagogical knowledge

From the position of axiological and systemic approaches the paper attempted to reflect the phenomenon of scientific and pedagogical knowledge, which genesis, evolution and formation was carried out in the process of historical development of society, bifurcational socio-cultural changes, and intensive deployment of knowledge in technological paradigms. The consideration of the essence and stages of the formation of knowledge, the main trends in its production and formation through the prism of changing, expanding and improving the terminological apparatus reflects the meanings in the philosophical ego-text of scientists, the development of emerging educational practices, new didactic samples. The authors conducted a typological analysis of the concept of “knowledge”, which makes it possible to state its indisputable philosophical significance, unconditional semantic content, undoubted phylogenetic essence, in accordance with which the paper appeals to cultural and historical paradigms; to education as the most important means of teaching and educating the subject; to the architectonics of the experience of becoming a subject in education by building knowledge potential and developing a thesaurus in a historical aspect, which contributed to the expansion of the sacred landscape of the individual by unfolding his practice of social design. Through the study of analytical differentiation and the identification of the orientation vector of scientific and pedagogical knowledge in the historical aspect, in the modeling of the cognitive picture of knowledge, the paper considers the development of the knowledge paradigm in technological paradigms through the problematic field of their main resource, basic factors, fundamental achievements and sources of narratives, which contributes to the establishment of the social nature of knowledge through the discovery of its main types, character, generation paths, markers of maturity.