Energy Distribution Research Articles

Patchy energy landscapes promote stability of small groups of active particles

Group formation and coordination are fundamental characteristics of living matter, essential for performing tasks and ensuring survival. Interactions between individuals play a key role in group formation, and the impact of resource distributions is a vibrant area of research. As of now, an understanding of how patchy resource distributions determine group dynamics is not yet fully understood. Studying active particles in controlled optical landscapes as energy sources, we demonstrate a non-monotonic dependency of group size on landscape patchiness, with the smallest groups forming when the patches match the active particles’ size. A similar relationship is observed in terms of group stability, evidenced by a reduced rate of individual exchange in patchy environments compared to homogeneous conditions. Reduced group sizes can be beneficial to optimise resources in heterogeneous environments and to control information flow within populations. Our results provide insights into the role of patchy landscapes and uneven energy distributions in active matter and hold implications for refining swarm intelligence algorithms, enhancing crowd management techniques, and tailoring colloidal self-assembly.

A Study on Hydrogen Bonding and Energy Variation during Bubble Nucleation in Water on a Grooved Substrate by Molecular Dynamics Simulation.

In this paper, the bubble nucleation process of water was studied by molecular dynamics (MD) simulation. The nucleation mechanism of water on a grooved substrate was revealed from the perspective of hydrogen bond and energy change, and the effect of system pressure on nucleation was studied. The results show that the process of bubble nucleation of water molecules is essentially a process in which the thermal motion of water molecules gradually intensifies and the hydrogen bond continues to break with the increase in kinetic energy. As the hydrogen bond breaks, the kinetic energy of the water molecules is continuously converted to intermolecular potential energy. By analyzing the composition of the hydrogen bond energy, it is found that the electrostatic energy is much greater than the van der Waals energy, so the water nucleation process mainly overcomes the electrostatic force between molecules. With the gradual increase of pressure, although the kinetic energy distribution of molecules does not change significantly, it will cause the potential energy of water molecules to decrease significantly and then lead to the increase of the energy barrier that needs to be crossed for nucleation. Meanwhile, the rise of the nucleation barrier may result in the absence of obvious initial vapor nuclei inside the liquid so that the number of hydrogen bonds cannot be rapidly reduced, which is not conducive to boiling nucleation. The results of this study provide important implications for further understanding of the nucleate boiling process of water.

Tunable Near-Field Radiative Heat Transfer between Graphene-Coated Magneto-Optical Metasurfaces.

The highly structured design of metasurfaces greatly facilitates the manipulation of near-field radiative heat transfer (NFRHT). In this study, we incorporate magneto-optical materials into metasurfaces to theoretically explore the mechanism for controlling NFRHT between anisotropic magneto-optical metasurfaces. Our findings indicate that the interaction between the magnetization-induced modes, arising from interband transitions of graphene, and the surface modes of InSb under a magnetic field leads to a transition in the heat transfer spectrum from a dual band to a triple band. The modification of the distribution and magnitude of transmission wave vectors in surface electromagnetic modes by magnetic fields serves to modulate the radiative heat flux. By combining active control by a magnetic field with passive structural design of metasurfaces, the regulation of heat flux can be increased by more than 8-fold compared with the planar configuration. Additionally, the magnetic field amplifies the anisotropy of the photon energy distribution induced by the symmetry breaking of the metasurface structure. This study is anticipated to provide a pathway for achieving flexible tuning of NFRHT by combining active and passive regulation. It also opens up possibilities for multiband information transmission and for improving the performance of energy conversion devices.

Exploring Negative Ion Behaviors and Their Influence on the Properties of DC Magnetron Sputtered ITO Films under Varied Power and Pressure Conditions

Abstract In this study, ITO films were deposited on silicon and quartz substrates by magnetron sputtering technology in pure argon. Using EQP plasma diagnostic technology, we study the effects of discharge power and discharge pressure on the ion flux and energy distribution function of incident on the substrate surface, with special attention to the production of high-energy negative oxygen ions, and elucidate the mechanism behind its production. At the same time, the structure and properties of ITO films were systematically characterized to understand the potential effects of high energy oxygen ions on the growth of ITO films. Combined with the kinetic property analysis of sputtering damage mechanism of transparent conductive oxide (TCO) thin films, it provides valuable physical understanding for the optimization of TCO thin film deposition process.

Development and Verification of Sampling Code NECP-SOUL for Evaluated Nuclear Data Files in ENDF-6 Format

A code called NECP-SOUL is developed to generate samples of evaluated nuclear data files in the ENDF-6 format. The motivation for the development is to obtain more accurate uncertainty quantification results based on the covariance data given in evaluated nuclear data files than the sampling method based on multigroup covariances. NECP-SOUL can handle all covariance data in ENDF-6 files, including average fission neutron multiplicities, resonance parameters, cross sections, angular distributions, energy distributions, and cross sections for the production of radioactive nuclides. In this work, samples of ENDF-6 files are input to the nuclear data processing code to generate A Compact ENDF (ACE)-formatted libraries, and these ACE-formatted libraries are used by the Monte Carlo code. Through statistical analysis, the uncertainty of the neutronics results can be obtained. NECP-SOUL is verified against another similar code, SANDY. In addition, the advantage of sampling ENDF-6 files is analyzed by comparing the uncertainty quantification results with those obtained by sampling multigroup covariance matrices. Moreover, the covariances of cross sections and angular distributions newly provided in ENDF/B-VIII.0 are used to analyze their effect on the uncertainty qualification results.

Numerical investigation gaseous ammonia basic jet and mixing characteristics in the constant volume vessel

Ammonia is considered a promising zero-carbon fuel under the dual-carbon targets. Systematically understanding ammonia's basic jet and mixing characteristics can promote its practical application in the engine field. Thus, a three-dimensional computational fluid dynamics (CFD) model of constant volume vessel (CVV) is established in this paper, and the forecasting abilities of the Large Eddy Simulation (LES) and Reynolds-Averaged Navier-Stokes (RANS) models for the gaseous ammonia jet process are compared based on the experimental data. Then, the ammonia jet development rule and mixing characteristics under different ambient temperatures, ambient pressures, and fuel temperatures are investigated. The variation laws of key data such as penetration distance, jet area, ammonia mass concentration distribution, equivalence ratio, and turbulent kinetic energy are obtained and analyzed. The results show that during the injection process, the airflow on the left and right sides of the jet rotates in opposite directions. A higher temperature and lower pressure within the CVV lead to a larger flammable range for ammonia jets. Moreover, the distribution of ammonia mass concentration on the radial plane shows a dynamic development law with time, meaning that it first increases to a maximum value, then gradually decreases, and finally remains stable. The farther the radial plane is from the nozzle outlet position, the lower the ammonia mass concentration. In addition, the ammonia jet's turbulent kinetic energy has a large core region and symmetrical distribution along the central axis. At the beginning of the injection, the core length is small, gradually increasing with time and finally stabilizing.

Framework design of distributed P2P2G energy transaction considering photovoltaic power and dispatch of manufacturing facilities

In this paper, a distributed peer-to-peer-to-grid (P2P2G) energy transaction framework considering photovoltaic generation and dispatch of manufacturing facilities is designed to increase the penetration of renewable energy resource. The factory with typical manufacturing assembly production task, photovoltaic panels and battery is regarded as a micro-grid (MG) to participate in the energy transaction market. The designed framework contains two levels. In the upper level, each MG determines the scheduling of manufacturing facilities and battery and the quantities of P2P2G energy transactions based on the given P2P energy transaction price and distribution locational marginal price (DLMP), in which the complex typical manufacturing assembly process is formulated as a kind of deferable load and the DLMP is updated according to the optimal power flow (OPF) of the network. In the lower level, peer-to-peer (P2P) energy transaction prices are updated by non-cooperative games and the homologous Rosen-Nash equilibrium points are obtained by using Nikaido-Isoda relaxation and alternating direction method of multipliers (ADMM) algorithm. The efficacy of the designed framework is demonstrated by a case study, and the results indicate the designed framework can improve the utilisation rate of renewable energy.

Using the phase characteristic for source depth discrimination with a horizontal line array for a broadband source

A solution to the problem of source depth discrimination in a shallow water waveguide is proposed for the case of a horizontal line array and low-frequency broadband sources. The method divides the horizontal line array into two subarrays with the same number of elements and then calculates the cross-power spectrum of beamforming pressure outputs of the subarrays. Depth-dependent features of phase fluctuation in the cross-power spectrum are analyzed using longitudinal correlation, and depth-separable decision metrics are defined. These decision metrics are poorly impacted by the energy distribution of the signal spectrum. Depth discrimination relies on the phase variation of the cross-power spectrum, and thus does not require mode space information or geoacoustic parameters as the prior knowledge, but sufficient effective horizontal apertures. Due to the application of beamforming, array gain can be obtained to improve the input signal-to-noise ratio of the phase feature-based discriminators. Simulations and Monte Carlo methods are applied to performance predictions and method comparison. The impact on the performance of signal-to-noise ratio, horizontal aperture, and array overlap is numerically studied. Finally, the method is experimentally demonstrated with data from a bottom-mounted horizontal line array deployed in the South China Sea, and the applicability of array overlap is illustrated.

Quamtum Mechanical Study on Structural and Electronic Properties of Tert-Butyl Based Bridged Dithiophene Oxide Derivatives

Computational modeling is vital to designing and creating organic semiconductors used in solar cells, organic field-effect transistors, and other areas. This work studied the structural and electronic features of a group of substituted tert-butyl bridged dithiophene oxide derivatives using Density Functional Theory (DFT) calculations. Geometry improvements were carried out using the B3LYP hybrid functional and the 6-31G(d,p) basis set in Gaussian 09. Molecular shapes, bond lengths, bond angles, and dihedral angles were studied to find out how substitution patterns change the packing and conformation of molecules. Energy levels, distribution, and makeup of frontier molecular orbitals were found. This calculation also included finding other electronic qualities, such as electronic charges, dipole moments, and polarizabilities. Findings show that tert-butyl substitution makes the molecular backbone stiffer and limits its ability to twist compared to similar molecules that have not been replaced. The chemical geometry stays mostly the same when electron-withdrawing or electron-donating substituents are added to the tert- butyl groups. Nevertheless, the strength and location of substituents have a significant impact on frontier orbital energies. The HOMO-LUMO gap grew significantly when the nitro or cyano groups firmly pulled electrons away from derivatives. For successful charge transport, electron density plots show that the HOMO and LUMO are mainly located on the thiophene and substituent moieties, respectively. Molecular dipole moments are also strongly affected by the electronic features of substituents. This research shows how to change the optoelectronic properties of tert-butyl-based dithiophene oxide derivatives and how their structure-property relationships can be improved. The results help makes new organic semiconductors that work better in various electronic and optoelectronic uses.

Machine learning-based prediction of the electron energy distribution function and electron density of argon plasma from the optical emission spectra

Machine learning-based prediction of the electron energy distribution function and electron density of argon plasma from the optical emission spectra

Plasma Catalysis-Driven Decomposition of CO2: Optimizing Energy Distribution with NiCo-CuO Catalyst

Plasma Catalysis-Driven Decomposition of CO₂: Optimizing Energy Distribution with NiCo-CuO Catalyst

Novel plasma actuator for mitigation of dynamic stall

A novel plasma actuator, the Linear Counter-flow using a Point Embedded Electrode (LCPEE), is developed for the prevention of dynamic stall for a sinusoidal pitching movement between α = 4° and α = 18°. The LCPEE is implemented on a NACA0012 airfoil and tested at a Reynolds Number of Re c = 2 × 105 and reduced frequency of k = π/16. Prior investigations using a standard linear actuator showed that the exposed electrode introduced perturbations passively which delayed dynamic stall when the actuator was off. For the LCPEE actuator, when turned off, there is least passive delay. When the LCPEE is turned on at St f = 50, the dynamic stall is prevented for the sinusoidal pitching motion of the airfoil. The LCPEE actuator is also tested for the same sinusoidal motion between α = 6° and α = 20°. Four cases are considered for the higher α range of motion: actuator off, actuator on at St f = 50 with a sinusoidal input waveform, actuator on at St f = 50 with a triangular input waveform, and actuator on at St f = 100 with a sinusoidal input waveform. Specifically for the last case, experiment shows no flow reversal demonstrating the efficacy of LCPEE in controlling the dynamic stall. The effects of LCPEE on the flow energy distribution have also been studied by using proper orthogonal decomposition (POD) method.

Research on Collision Restitution Coefficient Based on the Kinetic Energy Distribution Model of the Rocking Rigid Body within the System of Mass Points

Research on Collision Restitution Coefficient Based on the Kinetic Energy Distribution Model of the Rocking Rigid Body within the System of Mass Points

Matrix product state approximations to quantum states of low energy variance

We show how to efficiently simulate pure quantum states in one dimensional systems that have both finite energy density and vanishingly small energy fluctuations. We do so by studying the performance of a tensor network algorithm that produces matrix product states whose energy variance decreases as the bond dimension increases. Our results imply that variances as small as ∝1/log⁡N can be achieved with polynomial bond dimension. With this, we prove that there exist states with a very narrow support in the bulk of the spectrum that still have moderate entanglement entropy, in contrast with typical eigenstates that display a volume law. Our main technical tool is the Berry-Esseen theorem for spin systems, a strengthening of the central limit theorem for the energy distribution of product states. We also give a simpler proof of that theorem, together with slight improvements in the error scaling, which should be of independent interest.

Spectral Energy Distribution of Late Stage Stars

This paper presents a catalog of the energy distribution in the spectra of 263 stars in the wavelength range 0.4 - 100 µm, which are at late stages of evolution and have been observed by the ISO space observatory. For each object in the catalog, estimates of the observed bolometric fluxes are derived from smoothed energy distribution curves. The catalog is available at https://infra.sai.msu.ru/sai_lss_sed both as a table and in machine-readable format. It is shown that for the specified sample of objects their ISO SWS spectra in the range 2.4 - 45 µm only in 60% of cases correspond to the general shape of the continuum, and can be used without recalibration. A selection of carbon stars accessible to infrared observations from the MSU observatories was made. For some of them, the first brightness estimates in the K, L, and M bands were obtained with the new IR camera of the 2.5-m telescope of CMO.

Molecular beam scattering from flat jets of liquid dodecane and water

AbstractMolecular beam experiments in which gas molecules are scattered from liquids provide detailed, microscopic perspectives on the gas–liquid interface. Extending these methods to volatile liquids while maintaining the ability to measure product energy and angular distributions presents a significant challenge. The incorporation of flat liquid jets into molecular beam scattering experiments in our laboratory has allowed us to demonstrate their utility in uncovering dynamics in this complex chemical environment. Here, we summarize recent work on the evaporation and scattering of Ne, CD4, ND3, and D2O from a dodecane flat liquid jet and present first results on the evaporation and scattering of Ar from a cold salty water jet. In the evaporation experiments, Maxwell–Boltzmann flux distributions with a cosθ angular distribution are observed. Scattering experiments reveal both impulsive scattering (IS) and trapping followed by thermal desorption (TD). Super‐specular scattering is observed for all four species scattered from dodecane and is attributed to anisotropic momentum transfer to the liquid surface. In the IS channel, rotational excitation of the polyatomic scatterers is a significant energy sink, and these species accommodate more readily on the dodecane surface compared to Ne. Our preliminary results on cold salty water jets suggest that Ar atoms undergo some vapor‐phase collisions when evaporating from the liquid surface. Initial scattering experiments characterize the mechanisms of Ar interacting with an aqueous jet, allowing for comparison to dodecane systems.Key Points Molecular beam scattering from flat liquid jets is a powerful technique to elucidate mechanistic detail at the gas–liquid interface. Previous dodecane scattering experiments have uncovered angularly‐resolved thermal desorption fractions and energy transfer at the interface for several small molecule scatterers. Preliminary results on scattering from cold salty water reveal mechanisms of interaction between argon and an aqueous jet.

Molecular beam scattering from flat jets of liquid dodecane and water

AbstractMolecular beam experiments in which gas molecules are scattered from liquids provide detailed, microscopic perspectives on the gas–liquid interface. Extending these methods to volatile liquids while maintaining the ability to measure product energy and angular distributions presents a significant challenge. The incorporation of flat liquid jets into molecular beam scattering experiments in our laboratory has allowed us to demonstrate their utility in uncovering dynamics in this complex chemical environment. Here, we summarize recent work on the evaporation and scattering of Ne, CD4, ND3, and D2O from a dodecane flat liquid jet and present first results on the evaporation and scattering of Ar from a cold salty water jet. In the evaporation experiments, Maxwell–Boltzmann flux distributions with a cosθ angular distribution are observed. Scattering experiments reveal both impulsive scattering (IS) and trapping followed by thermal desorption (TD). Super‐specular scattering is observed for all four species scattered from dodecane and is attributed to anisotropic momentum transfer to the liquid surface. In the IS channel, rotational excitation of the polyatomic scatterers is a significant energy sink, and these species accommodate more readily on the dodecane surface compared to Ne. Our preliminary results on cold salty water jets suggest that Ar atoms undergo some vapor‐phase collisions when evaporating from the liquid surface. Initial scattering experiments characterize the mechanisms of Ar interacting with an aqueous jet, allowing for comparison to dodecane systems.Key Points Molecular beam scattering from flat liquid jets is a powerful technique to elucidate mechanistic detail at the gas–liquid interface. Previous dodecane scattering experiments have uncovered angularly‐resolved thermal desorption fractions and energy transfer at the interface for several small molecule scatterers. Preliminary results on scattering from cold salty water reveal mechanisms of interaction between argon and an aqueous jet.

Mechanism exploration of the modified asphalt binders with sustainable rapeseed-based derivatives using multi-scale evaluation method

Due to the concerns of sustainability, environment, and economy that are associated with non-renewable petroleum-based additives, there has been a growing interest in bio-additives derived from renewable feedstocks. This study aims to reveal the modification mechanism of three bio-additives derived from rapeseed on the base asphalt. The exploration of modification mechanism helped to explain the distinct rheological properties of bio-modified asphalt binders presented in a previous study. The effect of three bio-additives on the surface morphology, micro-mechanical properties, adhesivity, and chemical structure of base asphalt binders were investigated via Atomic Force Microscopy (AFM) and Fourier Transform Infrared spectrometer (FTIR) tests. The Electrostatic potential distribution and the orbital energy was analyzed via density functional theory (DFT) calculation to explore the inherit polarity of both the three bio-additives and asphalt components. Furthermore, molecular dynamic (MD) methods were used to evaluate the compatibility mechanism and aggregation tendency of asphalt components and bio-additives. The results showed that the electrostatic potential and the orbital energy of three bio-additives predominantly centered around the polar group. Specifically, AERO exhibited highest electrostatic potential distribution and lowest energy gap, indicating its heightened polarity. Moreover, the solution parameter difference value of bio-modified asphalt fell within 0.2 (J/m3)0.5, indicating great compatibility between asphalt and bio-additives, especially for ERO. Additionally, three bio-additives mitigated the aggregation of asphaltene within the asphalt due to their electrostatic interaction, especially notable in the cases of ERO and AERO. Furthermore, a cross-link network was formed within AERO-modified asphalt binders owing to its heightened polarity, fostering hydrogen bonding interactions internally and promoting the aggregation of saturate and resin factions around it. Consequently, this led to enhanced modulus and elasticity in the AERO-modified asphalt binders. Rapeseed derivatives as asphalt additives would be a sustainable and durable material for pavement construction and maintenance. It provides a theoretical basis for advancing the practical application of renewable vegetable oils in road engineering, which has exceptional economic and social benefits.

A new census of dust and polycyclic aromatic hydrocarbons at z=0.7-2 with JWST MIRI

This paper utilises the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) to extend the observational studies of dust and polycyclic aromatic hydrocarbon (PAH) emission to a new mass and star formation rate (SFR) parameter space beyond our local Universe. The combination of fully sampled spectral energy distributions (SEDs) with multiple mid-infrared (mid-IR) bands and the unprecedented sensitivity of MIRI allows us to investigate dust obscuration and PAH behaviour from $z=0.7$ up to $z=2$ in typical main-sequence galaxies. Our focus is on constraining the evolution of PAH strength and the dust-obscured luminosity fraction before and during cosmic noon, the epoch of peak star formation activity in the Universe. um um um um imaging data, enhancing our understanding of the physical characteristics of dust within these galaxies. We find a strong correlation between the fraction of dust in PAHs (PAH fraction qpah ) with stellar mass. Moreover the sub-sample with robust qpah measurements ($N=216$) shows a similar behaviour between qpah and gas-phase metallicity to that at $z suggesting a universal relation: qpah is constant ($ 3.4$<!PCT!>) above a metallicity of $Z odot $ and decreases to $<1$<!PCT!> at metallicities $ odot $. This indicates that metallicity is a good indicator of the interstellar medium properties that affect the balance between the formation and destruction of PAHs. The lack of a redshift evolution from $z 0-2$ also implies that above $Z odot $ the PAH emission effectively traces obscured luminosity and the previous locally calibrated PAH-SFR calibrations remain applicable in this metallicity regime. We observe a strong correlation between the obscured UV luminosity fraction (ratio of obscured to total luminosity) and stellar mass. Above the stellar mass of $M_*>5 Msun on average, more than half of the emitted luminosity is obscured, while there exists a non-negligible population of lower-mass galaxies with $>50<!PCT!>$ obscured fractions. At a fixed mass, the obscured fraction correlates with SFR surface density. This is a result of higher dust covering fractions in galaxies with more compact star-forming regions. Similarly, galaxies with high IRX (IR to UV luminosity) at a given mass or UV continuum slope (beta ) tend to have higher Ssfr and shallower attenuation curves, owing to their higher effective dust optical depths and more compact star-forming regions.

Engineering grain boundary energy with thermal profiles to control grain growth in SrTiO3

AbstractThis study investigates the influence of thermal history on grain boundary (GB) energy and the grain growth behavior of SrTiO3 at 1425°C. Two thermal profiles were explored: (1) a single‐step sintering at 1425°C for 1 h and (2) a two‐step profile with sintering completed at 1425°C for 1 h with an additional 10 h at 1350°C. Electron backscattered diffraction and atomic force microscopy were utilized to measure the grain size and GB energy distributions, respectively, for the samples before and after grain growth at 1425°C for 10 h. The two‐step profile exhibits fewer abnormal grains and a slower growth rate at 1425°C than the single‐step profile. Additionally, the two‐step sample comprises few high‐energy GBs and a narrow GB energy distribution, which suggests that it had a lower driving force for subsequent grain growth. The thermal profile was able to sufficiently change the growth rate such that the two‐step sample results in a finer grain size than observed for the single‐step sample after 10 h at 1425°C despite being exposed to elevated temperatures for almost twice as long. These results suggest that GB energy engineering through thermal profile modification can be used to control the grain growth rate and abnormal grain growth likelihood.