Short-range Systems Research Articles

Giant chiral amplification of chiral 2D perovskites via dynamic crystal reconstruction.

Chiral hybrid perovskites show promise for advanced spin-resolved optoelectronics due to their excellent polarization-sensitive properties. However, chiral perovskites developed to date rely solely on the interaction between chiral organic ligand cations exhibiting point chirality and an inorganic framework, leading to a poorly ordered short-range chiral system. Here, we report a powerful method to overcome this limitation using dynamic long-range organization of chiral perovskites guided by the incorporation of chiral dopants, which induces strong interactions between chiral dopants and chiral cations. The additional interplay of chiral cations with chiral dopants reorganizes the morphological and crystallographic properties of chiral perovskites, notably enhancing the asymmetric behavior of chiral 2D perovskites by more than 10-fold, along with the highest dissymmetry factor of photocurrent (gPh) of ~1.16 reported to date. Our findings present a pioneering approach to efficiently amplify the chiroptical response in chiral perovskites, opening avenues for exploring their potential in cutting-edge optoelectronic applications.

Implementation of diversity combining for radio monitoring of frequency-modulated signals

Formulation of the problem. Radio monitoring of short-range systems is often complicated by the presence of fading due to the complex interference pattern at the receiving point. An effective method of combating fading is a diversity combining. Standard methods of diversity combining require an estimate of the amplitude multiplier and (or) phase shifts when adding signals, which significantly complicates the procedure of spaced reception. The aim of the work is to explore the possibilities of a diversity combining without the need to estimate a complex channel multiplier. Results: the possibility of providing high noise immunity without the need to estimate the radio channel profile for signals with Gaussian frequency-shift keying (GFSK) in conditions of slow flat fading is demonstrated. A method has been developed for receiving GFSK signals, which makes it possible to combine two or more receiving channels to increase noise immunity in multipath conditions. Practical significance. The presented method has a relatively low computational complexity and makes it possible to increase the efficiency of radio monitoring systems.

УСВОЕНИЕ ДАННЫХ НАБЛЮДЕНИЙ В СИСТЕМЕ КРАТКОСРОЧНОГО ЧИСЛЕННОГО ПРОГНОЗА ПОГОДЫ COSMO-RU ГИДРОМЕТЦЕНТРА РОССИИ

The paper presents a system of regional data assimilation prepared and functioning at the Hydrometcenter of Russia for the COSMO-Ru short-range weather prediction system. It describes the assimilation methods used: both the nudging and latent heat nudging methods incorporated into the model and the developed surface temperature correction module. An optimal scheme for preparing the analysis fields and the assimilation cycle for obtaining refined initial data is also described. The presented scores of numerical experiments with and without assimilation show that the use of the detailed analysis allows improving the skill of the model very-short-range forecast, including the nowcasting interval, for the fields of temperature, humidity, wind, cloud cover, and precipitation. It is shown that the assimilation of precipitation based on radar data also makes it possible to simulate associated convective phenomena, including severe ones, much more accurately.

Assimilation of Observational Data in the COSMO-Ru Short-range Numerical Weather Prediction System of the Hydrometcenter of Russia

Assimilation of Observational Data in the COSMO-Ru Short-range Numerical Weather Prediction System of the Hydrometcenter of Russia

Relevant long-range interaction of the entanglement Hamiltonian emerges from a short-range gapped system

Relevant long-range interaction of the entanglement Hamiltonian emerges from a short-range gapped system

Design of Microstrip Array Antenna for Vehicle Millimeter Wave Radar

The design and construction of a microstrip array antenna especially intended for vehicle millimeter-wave radar applications in the 77–81 GHz frequency range is presented in this study. This study relies on earlier research on single-patch antennas to provide a full array design that satisfies the demanding performance requirements necessary for sophisticated car radar systems. The study carefully models and analyzes the antenna array using the High-Frequency Structure Simulator (HFSS) to get an azimuth angle of 90° within a 6 dB beamwidth and a pitch angle of 10° ± 1° within a 3 dB beamwidth. Achieving a gain of more than 13 dBi, keeping sidelobe levels below −15 dB, and guaranteeing isolation of more than 35 dB are all priorities in the design process. Precision and interference avoidance are crucial in high-resolution, short-range radar systems, and these factors are essential to the antenna’s operation. The array’s small form factor, along with factors like easy integration and economical production, make it an excellent choice for contemporary automobile radar applications. The research addresses the wider ramifications of this technology in vehicle safety and navigation in addition to diving into the technical issues of antenna design, such as the optimization of element spacing, array layout, and material selection. By exploring the limits of high-frequency antenna performance, this work advances the fields of autonomous cars and wireless communication technologies. The designed antenna array architecture is very adaptable, as shown by its possible applications ranging from point-to-point transmission and satellite communication to vehicle radar systems. The goal of this effort is to improve the capabilities of vehicle radar systems, which will lead to safer and more effective autonomous navigation solutions.

Numerically Optimized Fourier Transform-Based Beamforming Accelerated by Neural Networks

Conventional beamforming methods for reconfigurable reflector antennas assume full control over the amplitude and phase of the reflected field. Here, we develop a novel beamforming methodology for reflecting Programmable Metasurfaces (PMS) with capacitive memory. Although utilizing such fully reactive PMS simplifies antenna design and reduces energy consumption, the PMS reflection magnitude is unity and thus a global optimization of the reflection phases over the PMS unit cells is required in each beamforming scenario. We propose an implementation of such an optimization method rooted in the traditional Fourier transform-based beamforming and evaluate its performance. Additionally, we show that a pair of trained feed-forward neural networks (FFNN) with one input, one hidden, and one output layer can replace time-consuming global optimizations in the case of a PMS comprising 3×10 unit cells. We train the FFNNs on a dataset obtained for typical single- and dual-beam beamforming scenarios. After training, the FFNNs perform requested beamforming tasks within a fraction of second and with about the same accuracy as the original optimization algorithm. The proposed methodology may find applications in future mobile telecommunication systems that require real-time beamforming on low-end hardware. The same beamforming methodology can be also employed in short-range wireless power transfer systems.

Spatiotemporal variation in ecophysiological traits align with high resolution niche modelling in the short-range banded ironstone endemic Aluta quadrata.

Defining plant ecophysiological responses across natural distributions enables a greater understanding of the niche that plants occupy. Much of the foundational knowledge of species' ecology and responses to environmental change across their distribution is often lacking, particularly for rare and threatened species, exacerbating management and conservation challenges. Combining high-resolution species distribution models (SDMs) with ecophysiological monitoring characterized the spatiotemporal variation in both plant traits and their interactions with their surrounding environment for the range-restricted Aluta quadrata Rye & Trudgen, and a common, co-occurring generalist, Eremophila latrobei subsp. glabra (L.S.Sm.) Chinnock., from the semi-arid Pilbara and Gascoyne region in northwest Western Australia. The plants reflected differences in gas exchange, plant health and plant water relations at sites with contrasting suitability from the SDM, with higher performance measured in the SDM-predicted high-suitability site. Seasonal differences demonstrated the highest variation across ecophysiological traits in both species, with higher performance in the austral wet season across all levels of habitat suitability. The results of this study allow us to effectively describe how plant performance in A. quadrata is distributed across the landscape in contrast to a common, widespread co-occurring species and demonstrate a level of confidence in the habitat suitability modelling derived from the SDM in predicting plant function determined through intensive ecophysiology monitoring programmes. In addition, the findings also provide a baseline approach for future conservation actions, as well as to explore the mechanisms underpinning the short-range endemism arid zone systems.

Radio Beacon with the Function of Checking and Calibrating on Board Radio Receivers of the Instrument Landing System

A fundamentally new approach toverification and calibration of the on-board equipment of the radio beacon system for providing instrumental approach for an aircraft has been proposed, which consists of using directly radio beacons for these purposes that are in operation at existing airfields. Theoretically and experimentally, an original solution to the problem of checking and calibrating on-board equipment has been studied by generating landing radio signals with given values of the information parameter based on signals directly from the radio beacon and transmitting the generated signals through the surrounding space to the input of on-board receivers of the landing system. It is shown that commercially produced glide slope and localizer radio beacons of the decimeter wavelength range, supplemented by a signal combiner and a transmitting antenna with a radio frequency cable, will allow testing and calibration of on-board landing equipment with the accuracy that meets the requirements of GOST 15827–70. Monitoring the readings of the zero value of the information parameter on the indicator of the radio beacon system of the navigation and flight instrument by emitting signals from the glide slope radio beacon with a coefficient of inaudibility of signals equal to zero, has been experimentally confirmed when working with the short-range navigation radio system RSBN-2S and RSBN-PKV, which are part of AN aircraft –26Sh, TU-134Sh, TU-134UBL, located at the airfield in maintenance stops.

Control and Adjustment of Artillery Subunits' Fire Using Short-Range Air Reconnaissance Systems

Control and Adjustment of Artillery Subunits' Fire Using Short-Range Air Reconnaissance Systems

Method for improving the quality of service of request signals in information systems

The work notes that the request information systems are an important component of information support for air traffic control and airspace control systems. Interrogative information systems include: secondary radar systems, national identification radar systems and short-range navigation radio systems. It is shown that the characteristics of the process of servicing request signals in an aircraft transponder have a significant impact on the statistical properties of the response signal flow, which ultimately, as a consequence, affects the efficiency of the entire radar channel for transmitting response signals with an active response. It is pointed out that one of the important characteristics of the process of servicing request signals in an aircraft transponder is its correlation function, based on the analysis of which one can conclude the choice of the type of response signal flow and the structure of the aircraft transponder. This makes it possible to achieve: increasing the probability of service, increasing the probability of detecting an air object, reducing the root-mean-square error in estimating the azimuth of an air object and increasing the reliability of the transmission of flight information from the observed board of an air object. The article analyzes the possibility of improving the quality of request service by managing the flow of request signals in a network of request information systems. It has been shown that the correct choice of repetition periods of request signals in the area of joint operation of request information systems makes it possible to reduce the likelihood of interaction between individual request signals. Also, as a consequence, it makes it possible to increase the noise immunity of the interrogative information systems under consideration that are part of the specified information system.

Hypersonic Weapons: Evolution or Revolution?

Hypersonic strike systems have become a driving force in the development of offensive weapons. Academic literature offers two perspectives on the prospects of their impact on the military-strategic situation. One approach tends to position hypersonic weapons as a revolutionary technology, while the other proceeds from the premise that hypersonic strike systems represent an evolutionary development of offensive systems. The objective of this article is to establish the specifics and limits of the hypersonic weapons impact on the existing military-strategic balance. The paper analyzes the problem of hypersonic weapons classification, their role and place in military strategy, as well as the evolution and prospects of the Russian, U.S. and Chinese programs on hypersonic weapons. The authors conclude that the advantages of hypersonic weapons cannot automatically be transformed into a guaranteed success amid a full-scale military conflict and are largely available to other strike systems based on less advanced technological solutions. The key scenario, where the benefits of hypersonic weapons can be realized the most, is a limited conflict, in which they are used for the surprise defeat of highly-protected priority targets and the establishment of theater domination. This is evidenced by the hypersonic development programs of the leading military powers – Russia, the United States, and China, – each of which is more or less committed to developing medium- and short-range systems. The implications of the unfolding hypersonic arms race for strategic stability are ambiguous. On the one hand, forward deployment of such systems increases the risks of escalation; reduced flight time to enemy strategic infrastructure facilities encourages the adversary to adopt more aggressive retaliation postures based on the principle of launch-on-warning rather than post-attack. On the other hand, the possession of hypersonic weapons by both sides in the same theater increases their mutual vulnerability and can thus play a stabilizing role.

Adaptive ADMM-Based High-Quality Fast Imaging Algorithm for Short-Range MMW MIMO-SAR Systems

Adaptive ADMM-Based High-Quality Fast Imaging Algorithm for Short-Range MMW MIMO-SAR Systems

Electromagnetic Safety of Short-Range Radio Frequency Identification Systems

The intensive development of information and telecommunications technology has a very large impact on society. On the one hand, it greatly facilitates many activities in everyday life, such as searching for information, establishing contacts with other people, or controlling household appliances at a distance. On the other hand, it poses serious threats to our personal data, the information we process, or our property. One of the examples of such threats may be radio identification systems, enabling the registration of working time, entry into restricted zones in workplaces and offices, or warehouse data. Copying data from an identification card may allow unauthorized persons access to premises and data that they should not have. The article presents the principles of operation, the results of the conducted research, and their analysis in the aspect of security of the short-range radio frequency identification systems used in relation to the RFID 125 kHz system, broadly used in access control systems or time and attendance systems. Particular attention has been paid to the possibility of unauthorized acquisition of information contained in the identification card in order to, for example, copy it and gain access to specific protected zones. An analysis of the security of such systems was carried out not only in relation to the data carriers themselves but also to complete access control systems installed in buildings. The research focused especially on the ability to determine the range of information penetration, i.e., the distance of remote information acquisition using electromagnetic radiated emissions.

Phenomenology of the Prethermal Many-Body Localized Regime.

The dynamical phase diagram of interacting disordered systems has seen substantial revision over the past few years. Theory must now account for a large prethermal many-body localized regime in which thermalization is extremely slow, but not completely arrested. We derive a quantitative description of these dynamics in short-ranged one-dimensional systems using a model of successive many-body resonances. The model explains the decay timescale of mean autocorrelators, the functional form of the decay-a stretched exponential-and relates the value of the stretch exponent to the broad distribution of resonance timescales. The Jacobi method of matrix diagonalization provides numerical access to this distribution, as well as a conceptual framework for our analysis. The resonance model correctly predicts the stretch exponents for several models in the literature. Successive resonances may also underlie slow thermalization in strongly disordered systems in higher dimensions, or with long-range interactions.

Active Jamming Mitigation for Short-Range Detection System

Active Jamming Mitigation for Short-Range Detection System

РЕЗОНАНСНА СИСТЕМА БЕЗДРОТОВОЇ ПЕРЕДАЧІ ЕНЕРГІЇ З ВИКОРИСТАННЯМ ЕЛЕКТРИЧНОГО ПОЛЯ

The paper reviews the existing types of wireless technologies for power transmission using electromagnetic interaction. According to the type of interaction, systems using magnetic, electric and electromagnetic components are distinguished. Short-range, medium-range and long-range systems are distinguished by range. As promising for implementation in future unmanned systems, the work considers a modified system of wireless transmission of electrical energy using an electric field. The scheme is presented and the principle of operation of such a system is considered. The characteristics of resonant circuits used as emitters and receivers in such a system were studied. The results of measuring the parameters of the spatial distribution of the electric field of the resonators are presented. The interaction of the spectral components of the input signal and the resonant characteristics of the radiating circuits was investigated. The paper presents the method of determining the efficiency of electric energy transmission at high frequencies and the results of measurement of transmission efficiency for the studied type of systems. It was concluded that there is an active factor in the form of an alternating electric field, the feature of which propagation allows creating a device suitable for powering unmanned mobile systems of low and medium power. References 11, figures 4, tables 2.

Resultant equations for training load monitoring during a standard microcycle in sub-elite youth football: a principal components approach.

Applying data-reduction techniques to extract meaningful information from electronic performance and tracking systems (EPTS) has become a hot topic in football training load (TL) monitoring. The aim of this study was to reduce the dimensionality of the internal and external load measures, by a principal component approach, to describe and explain the resultant equations for TL monitoring during a standard in-season microcycle in sub-elite youth football. Additionally, it is intended to identify the most representative measure for each principal component. A principal component analysis (PCA) was conducted with a Monte Carlo parallel analysis and VariMax rotation to extract baseline characteristics, external TL, heart rate (HR)-based measures and perceived exertion. Training data were collected from sixty sub-elite young football players during a 6-week training period using 18 Hz global positioning system (GPS) with inertial sensors, 1 Hz short-range telemetry system, total quality recovery (TQR) and rating of perceived exertion (RPE). Five principal components accounted for 68.7% of the total variance explained in the training data. Resultant equations from PCA was subdivided into: (1) explosiveness, accelerations and impacts (27.4%); (2) high-speed running (16.2%); (3) HR-based measures (10.0%); (4) baseline characteristics (8.3%); and (5) average running velocity (6.7%). Considering the highest factor in each principal component, decelerations (PCA 1), sprint distance (PCA 2), average HR (PCA 3), chronological age (PCA 4) and maximal speed (PCA 5) are the conditional dimension to be considered in TL monitoring during a standard microcycle in sub-elite youth football players. Current research provides the first composite equations to extract the most representative components during a standard in-season microcycle in sub-elite youth football players. Futures research should expand the resultant equations within training days, by considering other well-being measures, technical-tactical skills and match-related contextual factors.

Velocity of interfaces with short and long ranged elasticity under sinusoidal creep

Plenty of research on elastic interfaces has been done on systems where the interface is pushed with a constant force. We studied the average velocity of an interface under a sinusoidal driving in the creep region, considering both short-range elastic systems, such as magnetic domain walls during a hysteresis loop, and long-ranged systems such as fractures. We obtained a modified version of the creep velocity with approximate power-law behavior and a material-dependent exponent for short ranged systems and simpler behavior for long-range elasticity. We discuss whether the model can be applied to fatigue fractures or if extra physics is needed.

JUSTIFICATION OF MODERNIZATION PATHS FOR SHORT-RANGE AIR DEFENSE MISSILE SYSTEMS OF LAND FORCES

Modern air defense systems of large, medium, short, and close range are among the most complex types of military equipment. The ability of a country to independently produce modern air defense systems is an indicator of the level of development of its defense industry. Therefore, the development, serial production, and modernization of these systems require a high level of scientific and technological advancement, as well as significant investment in research and development.
 During the full-scale invasion of Ukraine by the russian federation, both manned and unmanned aerial attack means were employed by the air and space forces. From the initial moments of the invasion, all components of the air defense encountered the need for the modernization of the existing air defense systems.
 The need for the modernization of existing air defense systems in Ukraine is justified by a comparative assessment of their tactical and technical characteristics with similar systems provided by Western partner countries within the framework of material and technical assistance. The modernization of air defense missile systems covering mechanized units will enhance the capability to detect and track targets, thereby increasing the effectiveness of the system in modern combat conditions.
 The issue of air defense system modernization has been the subject of numerous publications. These works discuss prospective directions for the development of short-range air defense systems, including the description of new technologies and materials that can be utilized to enhance the functionality and reliability of such systems. The publications focus on various methodological approaches to evaluate options for upgrading weapons and military equipment.