Practical Realization Research Articles

Steady-state entanglement in a hybrid optomechanical system enhanced by optical parametric amplifiers

In this paper, we investigate the degree of steady-state entanglement using a hybrid optomechanical system, where the separate cavities contain a degenerate optical parametric amplifier (DOPA). Particularly, under the linearization approximation, the steady-state entanglement is quantified through logarithmic negativity. The bipartite entanglement between cavity-mechanical oscillator modes and two cavity modes is analyzed through the applicable choice of nonlinear gain of OPA, optical cavity detuning, and cavity-cavity coupling strength. It is found that the steady-state entanglement increases with the nonlinear gain of OPA medium and normalized detuning. We further emphasize the influence of cavity-cavity coupling parameter on the bipartite entanglement, and the generation of entanglement can be transferred entirely due to the coupling strengths. The main contribution of coupling parameters on the entanglement of the two modes of mechanical oscillators significantly altered and increased. The observed possibility of transferring the emerging entanglement of the states of light in the two cavities to the modes of the accompanying mechanical oscillators is expected to be a valuable asset in the practical realization of quantum information processing.

Electrochemically activated Mn3O4 nanoparticles as higher performing electrode than MnO2 for Al-ion batteries – An insight into the crystallographic changes caused by Al3+ intercalation

Aluminium is the third most abundant element in the earth's crust, with a high theoretical capacity and volumetric energy density, making aluminium ion batteries (AIBs) a preferred technology for future large-scale energy storage applications amongst all of the proposed nonlithium-based battery systems. However, the practical realization of AIBs has so far been impeded by the frequent collapse of the host framework of the cathode materials. Here, nanostructure of Mn3O4 is being reported as a cathode material for aqueous AIBs to enhance the specific capacity, rate capability, and cycling stability. The various salts of aluminium were used as an electrolyte to verify how the composition of the electrolyte affected the intercalation and deintercalation of Al3+ in Mn3O4 electrode. In AlCl3 aqueous electrolyte, the Mn3O4 cathode exhibits the highest initial discharge capacity of ∼ 271 mAh g−1, at a high current density of 0.5 A g−1, with an excellent capacity retention of 98 % after 1,000 cycles. The outstanding cycling stability of the synthesized Mn3O4 nanoparticles is established by considering the phase transition from Mn3O4 spinel to MnO2 layered structure. The intercalation/deintercalation of Al3+ into/from the Mn3O4 crystal structure is also being confirmed by analysing the electrochemical performance in NaCl, KCl, and H2SO4 electrolyte.

Performance assessment of seawater fly ash cement paste with integrated physicochemical- geochemical simulation platform and experimental validation

The shortage of river sand and fresh water for concrete production has become a severe issue, accompanied by a significant increase in infrastructural constructions, especially for coastal areas. Therefore, the possibility of utilizing seawater and sea sand as alternative raw materials for concrete components has attracted broad research interest in recent decades. This paper presents experimental, and simulation investigation to comprehensively study the material performance of seawater fly ash cement paste (SFCP). An integrated simulation platform is adopted to achieve the performance assessment, in which the physicochemical and geochemical processes can be addressed, such as the hydration of cement particles, formation of micro-pore structure, multi-species migration and equilibria, activity effect, the thermodynamic balance between the matrix skeleton and pore solution. A comparison of experiment and simulation showed that the properties of SFCP from micro to macroscale are consistently associated and fairly explained through the integrated simulation platform for further practical realization.

학교현장실습에서 예비유아교사가 인식한 교사 역량에 대한 중요도 및 자기 실행도 분석

Objectives The purpose of this study is to identify the importance and self-performance level of teacher competencies recognized by pre-service early childhood teachers in school field practice, as well as the gaps, and to find effective strategies for the realization of kindergarten field practice.
 Methods To this end, a survey was conducted among 183 university students in the Department of Early Childhood Education in Seoul and Gyeonggi-do, who had completed kindergarten field training, asking about the importance and self-performance of teacher competencies. Descriptive statistics and corresponding sample t verification of importance and execution were performed, and importance-performance analysis (IPA) was performed to explore strategies.
 Results The importance and self-performance level of teacher competencies perceived by pre-service early childhood teachers in kindergarten field practice were both high, and the level of teacher competency recognition related to teaching personality was the highest. On the other hand, the competency related to learning guidance was relatively low, and especially in the field of learning guidance, the competency related to evaluation was the lowest. As a result of analyzing the difference between importance and performance, the level of performance was found to be low compared to the degree of importance, and the difference between importance and performance was statistically significant in all competencies except interpersonal competence. Finally, the IPA analysis showed that all teacher competencies were concentrated in quadrants 1 and 3. In the first quadrant, teaching passion, teaching ethics, teacher infant interaction, kindergarten life adaptation guidance, basic life guidance, personality guidance, interpersonal relationships, and communication capabilities were distributed. In addition, the three quadrants included curriculum content analysis, lesson plan establishment, learning environment creation, teacher presentation, learning material production and utilization, evaluation content and method, evaluation result utilization, early childhood observation and evaluation, health and safety guidance.
 Conclusions Competencies related to teaching personality need to be maintained continuously because both the level of importance and self-performance awareness are high, and the competencies related to learning guidance have a relatively low level of importance and self-performance awareness, so it is necessary to take measures to improve kindergarten field practice to increase them.

Effects of gas to water ratio and nano-Cu dosage on CH4 hydrate growth: A combined molecular simulation and experimental study

Natural gas hydrate (NGH) is a highly promising alternative for gas storage and transportation. Nevertheless, the artificial generation of gas hydrates faces considerable obstacles for large-scale commercial implementation, primarily due to its slow formation rate and inadequate storage density. This study delves into the effects of gas to water ratios and metal nanoparticle dosages on the synthesis of NGH. Molecular dynamics (MD) simulations were employed to examine the formation of CH4 hydrate under varying gas to water ratios and metal nanoparticle concentrations. The investigation assessed critical parameters of the gas–water system, such as radial distribution function, carbon storage ratio, hydrate cages, potential energy, diffusion coefficient, and thermal conductivity. For the first time, Pearson's correlation coefficient analysis was utilized to discern the interrelationships among these factors. The results demonstrated that medium gas to water ratios led to increased carbon storage, a higher number of cages, and augmented energy consumption. The nano-Cu dosage impacted the stability of hydrates and the thermal conductivity of the gas–water system, particularly at elevated gas to water ratios. Drawing on the MD simulation findings, a design factor was introduced to appraise the performance of the multicomponent system, which in turn, informs the development of a high-performance NGH formation system. The effectiveness of the design factor was corroborated through laboratory experiments, revealing its robust potential for designing high-performance NGH systems. This research paves the way for the practical realization of efficient hydrate-based production in real-world applications.

Multichannel Metasurfaces with Frequency‐Direction Multiplexed Amplitude and Phase Modulations

AbstractElectromagnetic wave multiplexing within a compact ultrathin device is pivotal for high‐capacity communications, wireless power transfer, and other applications. Among them, the independent amplitude and phase (AP) control is necessary, and the decoupling of full‐space scattering channels such as reflection (R) and transmission (T) is favoured for high capacities of information processing. This is yet extremely challenging, even at a single frequency, because A and P are essentially correlated and the R‐T channels are usually coupled. Here, a triband multichannel metasurface is proposed and demonstrated, with a frequency‐direction multiplexed paradigm for on‐demand control of both AP across three independent R‐T channels. For practical realization with high efficiency, a judiciously engineered four‐layer compound meta‐atom is proposed. Such a sophisticated multiplexing can facilitate powerful capability in wavefront control and significantly enrich the capacity as well as degrees of freedom for design. For verification, a proof‐of‐concept metadevice has been devised and experimentally demonstrated at microwave frequency, showcasing transmissive and reflective dual‐vortex beams along x and y directions at 7 and 10.2 GHz, respectively, while transmissive dual focusing at 15.7 GHz. This strategy opens a new avenue for circularly‐polarized AP control toward the capacity limit of frequency and direction and for novel functional metadevices with high integration.

Competitive Relaxation Mechanisms in Strained Epitaxial InGaSb on GaSb Substrate

Hetoroepitaxial growth of III-V compounds can produce both novel structures for fundamental research and electronic/photonic devices for practical applications. Antimony-based compounds are interested since they can interact with light in longer wavelengths ranging from near-infrared to terahertz frequency domains. In this work, we present an experimental observation of step-decorated surface and dislocation lines formed in an epitaxial In0.17Ga0.83Sb layer. The growth is performed by solid-source molecular beam epitaxy on (001) GaSb substrate at 400°C with the InGaSb deposition rate of 0.12 monolayer per second. The atomic force microscopy shows that the regular atomic steps are generally misaligned with the surface dislocation lines. The average distance between the steps is about 200 nm and the presence of dislocation lines affects the subsequent growth. Zigzag step-edge structure observed near the intersection of the step-edges and the dislocation lines can be explained by simple strain-considered models. Enhanced and depleted growth areas can be related to the degree of underneath strain. The understanding of this phenomena might lead to the simple and practical realization of regular arrays of nanostructures such as quantum wires and quantum dots.

Design and Optimization of 4-way set Associative Mapped Cache Controller

Abstract: In the realm of modern computer systems, the 4-way set associative mapped cache controller emerges as a cornerstone, revolutionizing memory access efficiency. This exploration delves into its core principles, revealing its pivotal role in synchronizing rapid CPUs with slower main memory. By orchestrating seamless data exchange and employing intelligent replacement policies, this controller optimizes performance. Embarking on practical realization, a non-pipelined processor materializes using Xilinx Vivado and Verilog HDL, propelling frequent memory read/write requests for the 4-way set associative mapped cache. The quest for efficiency fuels refinements, culminating in an optimized cache controller design. Rigorously validated within the Xilinx Vivado environment, the architecture demonstrates tangible success with quantified outcomes. The design framework encompasses a 4K byte primary memory, complemented by a 1K byte 4-way set associative cache. This setting scrutinizes the optimized cache controller's efficacy. The dedicated test module, housing a suite of instructions, underscores its performance. Remarkably, the evaluation showcases 19 cache hits and 6 cache misses, revealing the potency of the optimized design in minimizing cache misses, particularly in call and jump instructions, an essential stride towards enhanced memory efficiency.

Quantifying the Relaxation Dynamics of Higher Electronic Excited States in Perylene.

Gating logical operations through high-lying electronic excited states presents opportunities for developing ultrafast, subnanometer computational devices. A lack of molecular systems with sufficiently long-lived higher excited states has hindered practical realization of such devices, but recent studies have reported intriguing photophysics from high-lying excited states of perylene. In this work, we use femtosecond spectroscopy supported by quantum chemical calculations to identify and quantify the relaxation dynamics of monomeric perylene's higher electronic excited states. The 21B2u state is accessed through single-photon absorption at 250 nm, while the optically dark 21Ag state is excited via the 11B3u state. Population of either state results in subpicosecond relaxation to the 11B3u state, and we quantify 21Ag and 21B2u state lifetimes of 340 and 530 fs, respectively. These lifetimes are significantly longer than the singlet fission time constant from the perylene 21B2u state, suggesting that the higher electronic states of perylene may be useful for gating logical operations.

Уголовно-правовое воздействие, меры уголовно-правового характера, уголовная ответственность и иные меры уголовно-правового характера: проблемы соотношения уголовно-правовых категорий

The article considers the issue of correlation of the following criminal-law categories: criminal-law impact, pe-nal measures, criminal liability, other measures of criminal and legal nature. Having investigated them using the method of lexical analysis, by formulating his own definition of measures of criminal-legal nature, defining their signs and system, the author comes to the reasonable conclusion that the criminal law impact is repre-sented by many types, including penal law, implemented by means of measures of criminal-legal nature, en-shrined in the criminal law, law enforcement acts, etc. Measures of a criminal law are expressed by criminal liability and other measures of a criminal-legal nature, the specific features of which are their non-punitive na-ture and the absence of interrelation with criminal liability (with the rare exception of cases of their simultane-ous practical realization), which allows to distinguish them in the system by means of criminal-legal coercion.

First Principles Investigations of Electrocatalyst Design for Mg-CO2 Batteries

Carbon di-oxide (CO2) is the leading greenhouse gas responsible for global warming and catastrophic consequences on environmental imbalance. Metal-CO2 batteries have grabbed significant attention in the scientific community because of the unique feature of simultaneously consuming CO2 for the production of green electricity. In this regard, Mg- CO2 battery is especially highly promising because of its high volumetric capacity, low-cost, natural abundance. However, several roadblocks such as sluggish reaction kinetics of CO2 reduction, poor reversibility during charging and discharging cycles, and high charge overpotential needs to overcome the practical realization of Mg-CO2 batteries. The target performance of Mg-CO2 batteries can only be achieved through developing efficient cathode catalysts. In this study, we employ first-principles density functional theory (DFT) calculations to screen for electrocatalysts to achieve expedited reaction kinetics. Single-atom catalysts (SACs) are atomically dispersed metal atoms on a substrate and have evolved as an established strategy for ensuring the maximum utilization of catalytically active atoms in heterogeneous catalysis. The high throughput DFT simulations will be leveraged to understand the adsorption behavior of the reaction intermediates of Mg-CO2 batteries on the SACs. The derived free energy profile will illustrate the favorable reaction pathways to identify high performing SACs. The screening will be spanned over the first two rows of the transition metals.

The SWITCH test for discriminating quantum evolutions

We study different quantum circuits that can discriminate between two arbitrary quantum evolution operators. These circuits can be used to check whether two quantum operators are equal or not and to estimate a fidelity measure telling how close the operators are. This operator comparison is related to the SWAP test for discriminating two quantum states. In terms of their practical realization, we comment possible laboratory implementations with light along the same lines of recent experimental realizations of quantum superpositions of causal orders exploiting the different degrees of freedom of photons. We also discuss hardware efficient realizations for noisy intermediate scale quantum computers. Finally, we comment potential applications to the discrimination of quantum communication channels and to the search for simpler quantum circuits in quantum compilers.

Machine learning assisted quantum super-resolution microscopy

One of the main characteristics of optical imaging systems is spatial resolution, which is restricted by the diffraction limit to approximately half the wavelength of the incident light. Along with the recently developed classical super-resolution techniques, which aim at breaking the diffraction limit in classical systems, there is a class of quantum super-resolution techniques which leverage the non-classical nature of the optical signals radiated by quantum emitters, the so-called antibunching super-resolution microscopy. This approach can ensure a factor of sqrt{n} improvement in the spatial resolution by measuring the n -th order autocorrelation function. The main bottleneck of the antibunching super-resolution microscopy is the time-consuming acquisition of multi-photon event histograms. We present a machine learning-assisted approach for the realization of rapid antibunching super-resolution imaging and demonstrate 12 times speed-up compared to conventional, fitting-based autocorrelation measurements. The developed framework paves the way to the practical realization of scalable quantum super-resolution imaging devices that can be compatible with various types of quantum emitters.

Spline standard of mapped informativeness of correlation-extreme navigation as the potential of cybernetic situational awareness

A hypothesis about the possibility of using a spline standard of mapped informativeness of correlation-extreme navigation as a potential for cybernetic awareness is put forward. The expediency of understanding cybernetic awareness as an ontological engineering of the geometric implementation of a spline fragment of mapping to ensure the principle of alternative positioning is revealed. The forecast of the achievability of the effect of the vessel location predictability in the local environment of the satellite signals incapacity in the practical realization of the potential of situational awareness is made. The possibility of conceptual resistance of the developed algorithms of malicious virtual interference due to the unique composition of spline functions in assessing the vulnerability of the bridge onboard computers to a cybernetic threat is substantiated. Attention is focused on the fundamental impossibility of distorting the spline standard of informativeness to disrupt the classical process of linking the measured exposure of the navigation field to the reference one to ensure autonomous positioning of moving objects in any hacker attacks on the target mathematical asset. The main reason for the stability of approximation constructions, which lies in the piecewise architecture of the spline, when local violations of mathematical composition do not affect the overall task of forming a realistic navigation isosurface as a graphical structure of semantic modeling, is revealed. The proposals of effective information processing as attributes of cybernetic awareness are tested on the example of computer visualization of measuring fields of bathymetry and maps of magnetic anomalies in the form of fragments of threedimensional spreading of the planetary magnetic field. The developed package of application programs is adapted to synthesize a spline standard of mapped informativeness in the cybernetic awareness paradigm as an intellectual support for decision-making by a navigator in order to reduce his psychological cognitive load. It is proposed to use the potential of situational awareness as a mathematical support for an automated navigation system with artificial intelligence within the framework of the concept of unmanned navigation in strategic accordance with the A-Navigation project. The fundamental importance of a positive assessment of cybernetic awareness in promoting the practical use of autonomous marine surface vessels in modern navigation practice is determined.

Macroscopic negative differential thermal resistance in the overlapping graphene homojunction structure

As one of the most potential ways to manipulate heat, thermal functional devices have achieved several breakthroughs in recent years, but are still limited to theoretical simulations. One of its theoretical bases is the existence of the negative differential thermal resistance (NDTR). However, most of the existing systems where the phenomenon of NDTR is found are atomic-level systems. In order to realize the macroscopic NDTR and provide effective theoretical guidance and support for the practical realization of thermal functional devices, we construct the overlapping graphene homojunction model, using the negative thermal expansion property of graphene to modify the overlapping area, and thus regulating the heat flow. The COMSOL-MATLAB co-simulation is used to perform calculations through negative feedback loops. It is found that the NDTR phenomenon exists under certain parameter conditions, which can provide new ideas and bring more opportunities for the experimental realization of nonlinear thermal functional devices.

Guiding maps of solvents for lithium-sulfur batteries via a computational data-driven approach

Practical realization of lithium-sulfur batteries requires designing optimal electrolytes with controlled dissolution of polysulfides, high ionic conductivity, and low viscosity. Computational chemistry techniques enable tuning atomistic interactions to discover electrolytes with targeted properties. Here, we introduce ComBat (Computational Database for Lithium-Sulfur Batteries), a public database of ∼2,000 quantum-chemical and molecular dynamics properties for lithium-sulfur electrolytes composed of solvents spanning 16 chemical classes. We discuss the microscopic origins of polysulfide clustering and the diffusion mechanism of electrolyte components. Our findings reveal that polysulfide solubility cannot be determined by a single solvent property like dielectric constant. Rather, observed trends result from the synergistic effect of multiple factors, including solvent C/O ratio, fluorination degree, and steric hindrance effects. We propose binding energy as a proxy for Li+ dissociation, which is a property that impacts the ionic conductivity. The insights obtained in this work can serve as guiding maps to design optimal lithium-sulfur electrolyte compositions.

Topological Dirac Spin‐Gapless Materials ‐ a New Horizon for Topological Spintronics Without Spin‐Orbit Interaction

AbstractThe existence of chiral edge states (CES), corresponding to nontrivial bulk‐band topology characterized by a non‐vanishing topological invariant, and the manipulation of topological transport via CES promise topological electronic/spintronic device applications. This study predicts the existence, practical realization, topological protection, and topological switching of spin‐gapless valley‐filtered chiral edge states (SG‐VF‐CES), representing a novel topological Dirac spin‐gapless/half‐metal phase in antiferromagnetic honeycomb structures terminated on zigzag edges. It demonstrates that this phenomenon is realizable if a perpendicular (transverse) electric field is applied in zigzag nanoribbons with an antiferromagnetic ordering on the boundary (in the bulk), and the Weber‐Fechner type nonlinear behavior is optimizable by a transverse (perpendicular) electric field. The existence of SG‐VF‐CES, their correspondence with nontrivial topological character in the bulk, and electric‐field‐driven switching of their spin‐polarization that is accompanied by switching of bulk‐band topology promise a new strategy for topological spintronics without spin‐orbit interaction (SOI).

Analysis of Discrete Velocity Models for Lattice Boltzmann Simulations of Compressible Flows at Arbitrary Specific Heat Ratio

This paper is devoted to the comparison of discrete velocity models used for simulation of compressible flows with arbitrary specific heat ratios in the lattice Boltzmann method. The stability of the governing equations is analyzed for the steady flow regime. A technique for the construction of stability domains in parametric space based on the analysis of eigenvalues is proposed. A comparison of stability domains for different models is performed. It is demonstrated that the maximum value of macrovelocity, which defines instability initiation, is dependent on the values of relaxation time, and plots of this dependence are constructed. For double-distribution-function models, it is demonstrated that the value of the Prantdl number does not seriously affect stability. The off-lattice parametric finite-difference scheme is proposed for the practical realization of the considered kinetic models. The Riemann problems and the problem of Kelvin–Helmholtz instability simulation are numerically solved. It is demonstrated that different models lead to close numerical results. The proposed technique of stability investigation can be used as an effective tool for the theoretical comparison of different kinetic models used in applications of the lattice Boltzmann method.

Practical realization of space-time filtering of satellite navigation signals in real time

Background. The problem of satellite navigation signals’ jamming-protected receivers design is quite relevant due to the high vulnerability of such signals to the influence of interferences whose sources number is constantly increasing. Aim. To design a space-time adaptive filter and to implement its work in real-time as a part of jamming-protected satellite navigation system. Methods. The space-time filtering method fitted for the real-time realization is obtained based on the satellite signal space processing algorithm. The apparatus chosen for the satellite navigation signals reception, the filtering algorithm practical realization and the processed signal demodulation is described. The computer modeling of the signals records filtering and demodulation using the obtained algorithm as well as the real-time experiments in satellite signals processing with different numbers of outer jammers using the constructed jamming-protected receiver are carried out. Results. As a result of modeling and experiments with the designed set the values of performance characteristics of the jamming-protected navigation system are yielded which correspond to a good quality solution of the interference mitigation problem in a satellite navigation signal. Conclusion. The digital processing model based on the obtained space-time filter adequately describes the interference mitigation process in a real satellite signal. The obtained jamming-protected satellite navigation signal receiver is functional and can be used in practice.

(Audio)visual Artivist Research in Anti-Colonial and Anti-Racist Key

This article conceives of the University as a laboratory for the creation of anti-racist and anti-colonial practices through arts, communication, and education. It proposes the realization of (audio)visual artivist practices with an anti-colonial and anti-racist focus as the articulating axis of artistic creation experiences, art education, and educational research. It suggests the creation and exhibition of commented collages and short films of appropriation as instruments for individuals and groups to question colonialism and racism, both in the fields of audiovisual, visual, and sound culture, as well as in the field of their family, school, and cultural consumption formation; while promoting the re-existence of native and Afro-descendant identities, cultures, knowledge, and memories. It employs conceptual and methodological tools of critical pedagogy, visual anthropology, and film studies to describe how anti-“Indian” and anti-“Black” racism and the appreciation for cultural and physical whiteness can be reproduced and resisted. It recovers testimonies from situated processes of critical reflection on one’s personal and family history in relation to the reproduction of colonial and racist violence. It describes a methodological proposal to make (audio)visual artistic analysis and creation tools in the construction of knowledge and emotions for the social transformation of reality, and instruments to build a culture of peace, social justice, and historical memory.