Search

We have performed a series of broadband multidimensional electronic spectroscopy experiments to probe the electronic and vibrational dynamics of the canthaxanthin chromophore of the Orange Carotenoid Protein (OCP) from Synechocystis sp. PCC 6803 in its photoactivated red state, OCPR. Cross-peaks observed below the diagonal of the two-dimensional electronic spectrum indicate that absorption transitions prepare the bright S2 state of the ketocarotenoid canthaxanthin near to a sequence of conical intersections, allowing passage to the dark S1 state via the Sx intermediate in < 50 fs. Rapid damping of excited-state coherent wavepacket motions suggests that the branching coordinates of the conical intersections include out-of-plane deformation and C=C stretching coordinates of the π-conjugated isoprenoid backbone. The unusual proximity of the Franck–Condon S2 state structure to the conical intersections with Sx and S1 suggests that the protein surroundings of canthaxanthin prepare it to function as an excitation energy trap in the OCPR–phycobilisome complex. Numerical simulations using the multimode Brownian oscillator model demonstrate that the ground-state absorption spectrum of OCPR overlaps with the fluorescence emission spectrum of allophycocyanin due to spectral broadening derived especially from the intramolecular motions of the canthaxanthin chromophore in its binding site. [ABSTRACT FROM AUTHOR]

Recent quantum algorithms pertaining to electronic structure theory primarily focus on the threshold-based dynamic construction of ansatz by selectively including important many-body operators. These methods can be made systematically more accurate by tuning the threshold to include a greater number of operators into the ansatz. However, such improvements come at the cost of rapid proliferation of the circuit depth, especially for highly correlated molecular systems. In this work, we address this issue by the development of a novel theoretical framework that relies on the segregation of an ansatz into a dynamically selected core "principal" component, which is, by construction, adiabatically decoupled from the remaining operators. This enables us to perform computations involving the principal component using extremely shallow-depth circuits, whereas the effect of the remaining "auxiliary" component is folded into the energy function via a cost-efficient non-iterative correction, ensuring the requisite accuracy. We propose a formalism that analytically predicts the auxiliary parameters from the principal ones, followed by a suite of non-iterative auxiliary subspace correction techniques with different levels of sophistication. The auxiliary subspace corrections incur no additional quantum resources yet complement an inadequately expressive core of the ansatz to recover a significant amount of electronic correlations. We have numerically validated the resource efficiency and accuracy of our formalism with a number of strongly correlated molecular systems. [ABSTRACT FROM AUTHOR]

In thin film deposition, Ar/SiH4 mixtures are widely used to make polysilicon (poly-Si) and hydrogenated amorphous silicon (a-SiH) layers. Despite extensive research conducted on this mixture, little research has focused on the variations in plasma properties, radicals, and ions that occur during plasma discharge in inductively coupled plasma (ICP) equipment compared to capacitive coupled plasma equipment. In this paper, we investigate the properties of the plasma generated through mathematical modeling of Ar/SiH4 inductive coupled plasma discharge by using the electron energy distribution function (EEDF) obtained by solving the Boltzmann equation. We closely examine the variation in plasma properties and the correlation of plasma variables by controlling the radio frequency power and gas pressure during the process conditions. The Boltzmann equation was computed by assuming the two-term approximation, resulting in a Druyvesteyn-like EEDF due to the high-pressure conditions. To validate the simulation model, the 2D simulation results were compared with probe measurements performed in a two-turn ICP chamber. The results demonstrated encouraging agreement with the measured data. This research not only enhances our comprehension of the discharge characteristics but also establishes a framework for optimizing the discharge conditions to enhance the process and effectively regulate external variables. [ABSTRACT FROM AUTHOR]

The Landau levels (LLs) and magneto-optical responses in the AA-stacked bilayer transition metal dichalcogenides in the presence of an exponentially decaying magnetic field are investigated. Sixteen separate Landau levels are predicted in the numerical results, which are the result of the spin, valley, and layer degeneracy lifting induced by the spin Zeeman field. Interestingly, we find that the ∇ B drift velocity perpendicular to the magnetic field gradient is τ ⋅ s -degenerate and independent of the layer index and the strength of the spin Zeeman field. Based on the linear-response theory, the magneto-optical conductivity is derived as a function of photon energy where only the intraband transition associated with the incident light in the THz regime is considered. Our result reveals that the merit of absorption peaks in the real part of longitudinal conductivity under the nonuniform magnetic field is influenced by the combined effect of the optical transition selection rule and the mixing rule of Landau states. Moreover, the response of optical conductivity is significantly modified when the inhomogeneity of the magnetic field, i.e., ξ 0 , is varied. Furthermore, the position of optical response is found to shift toward the high magneto-excitation frequency as ξ 0 increases. [ABSTRACT FROM AUTHOR]

A ledge feature in the capacitance–voltage (CV) profiles of Ga2O3 MOS (metal–oxide–semiconductor) capacitors is investigated using UV-assisted CV measurements. A model is presented whereby the capacitance ledge is associated with carrier trapping in deep-level states at the Al2O3/Ga2O3 interface. Following UV assisted emptying of interface traps at a constant bias, a voltage ramp toward flatband results in a CV ledge when the trap recombination current becomes equal to the quasi-static sweep charging current. The ledge continues until all the traps below the corresponding pinned surface potential have been filled. Varying the UV energy varies the ledge voltage range and allows a density of states to be determined as a function of energy. A broad interface state peak with maximum density ∼8 × 1012 cm−2 eV−1 for deep trap energies lying between 2.4 and 4.1 eV below the conduction band (CB) edge is extracted. Using the conductance method, the interface trap density is also found to rise toward the CB edge in the range 0.25–0.45 eV below the CB edge, reaching a maximum density of ∼1 × 1012 cm−2 eV−1. Combining these two techniques, an interface trap distribution is estimated for almost the entirety of the bandgap of Ga2O3. This novel technique probes deep interface states where standard methods fail to quantify interface states reliably. [ABSTRACT FROM AUTHOR]

We present an exchange–correlation approximation in which the Coulomb interaction is split into long- and short-range components and the range separation is determined by a non-empirical density functional. The functional respects important constraints, such as the homogeneous and slowly varying density limits, leads to the correct long-range potential, and eliminates one-electron self-interaction. Our approach is designed for spectroscopic purposes and closely approximates the piecewise linearity of the energy as a function of the particle number. The functional's accuracy for predicting the fundamental gap in generalized Kohn–Sham theory is demonstrated for a large number of systems, including organic semiconductors with a notoriously difficult electronic structure. [ABSTRACT FROM AUTHOR]

We present a detailed assessment of deep neural network potentials developed within the Deep Potential Molecular Dynamics (DeePMD) framework and trained on the MB-pol data-driven many-body potential energy function. Specific focus is directed at the ability of DeePMD-based potentials to correctly reproduce the accuracy of MB-pol across various water systems. Analyses of bulk and interfacial properties as well as many-body interactions characteristic of water elucidate inherent limitations in the transferability and predictive accuracy of DeePMD-based potentials. These limitations can be traced back to an incomplete implementation of the "nearsightedness of electronic matter" principle, which may be common throughout machine learning potentials that do not include a proper representation of self-consistently determined long-range electric fields. These findings provide further support for the "short-blanket dilemma" faced by DeePMD-based potentials, highlighting the challenges in achieving a balance between computational efficiency and a rigorous, physics-based representation of the properties of water. Finally, we believe that our study contributes to the ongoing discourse on the development and application of machine learning models in simulating water systems, offering insights that could guide future improvements in the field. [ABSTRACT FROM AUTHOR]

Estimating the rate of rare conformational changes in molecular systems is one of the goals of molecular dynamics simulations. In the past few decades, a lot of progress has been done in data-based approaches toward this problem. In contrast, model-based methods, such as the Square Root Approximation (SqRA), directly derive these quantities from the potential energy functions. In this article, we demonstrate how the SqRA formalism naturally blends with the tensor structure obtained by coupling multiple systems, resulting in the tensor-based Square Root Approximation (tSqRA). It enables efficient treatment of high-dimensional systems using the SqRA and provides an algebraic expression of the impact of coupling energies between molecular subsystems. Based on the tSqRA, we also develop the projected rate estimation, a hybrid data-model-based algorithm that efficiently estimates the slowest rates for coupled systems. In addition, we investigate the possibility of integrating low-rank approximations within this framework to maximize the potential of the tSqRA. [ABSTRACT FROM AUTHOR]

Selected configuration interaction (SCI) methods have emerged as state-of-the-art methodologies for achieving high accuracy and generating benchmark reference data for ground and excited states in small molecular systems. However, their precision relies heavily on extrapolation procedures to produce a final estimate of the exact result. Using the structure of the exact electronic energy landscape, we provide a rationale for the common linear extrapolation of the variational energy as a function of the second-order perturbative correction. In particular, we demonstrate that the energy gap and the coupling between the so-called internal and external spaces are the key factors determining the rate at which the linear regime is reached. Starting from the first principles, we also derive a new non-linear extrapolation formula that improves the post-processing of data generated from SCI methods and can be applied to both ground- and excited-state energies. [ABSTRACT FROM AUTHOR]

A Landau–Devonshire thermodynamic energy density function for ferroelectric wurtzite aluminum scandium nitride (Al1−xScxN) solid solution is developed. It is parametrized using available experimental and theoretical data, enabling the accurate reproduction of composition-dependent ferroelectric properties, such as spontaneous polarization, dielectric permittivity, and piezoelectric constants, for both bulk and thin films. The maximum concentration of Sc for the wurtzite structure to remain ferroelectric is found to be 61 at. %. A detailed analysis of Al1−xScxN thin films reveals that the ferroelectric phase transition and properties are insensitive to substrate strain. This study lays the foundation for quantitative modeling of novel ferroelectric wurtzite solid solutions. [ABSTRACT FROM AUTHOR]

The energetic stability of positron–dianion systems [A−; e+; A−] is studied via many-body theory, where A− includes H−, F−, Cl−, and the molecular anions (CN)− and (NCO)−. Specifically, the energy of the system as a function of ionic separation is determined by solving the Dyson equation for the positron in the field of the two anions using a positron–anion self-energy as constructed in Hofierka et al. [Nature 606, 688 (2022)] that accounts for correlations, including polarization, screening, and virtual-positronium formation. Calculations are performed for a positron interacting with H 2 2 − , F 2 2 − , and Cl 2 2 − and are found to be in good agreement with previous theory. In particular, we confirm the presence of two minima in the potential energy of the [H−; e+; H−] system with respect to ionic separation: a positronically bonded [H−; e+; H−] local minimum at ionic separations r ∼ 3.4 Å and a global minimum at smaller ionic separations r ≲ 1.6 Å that gives overall instability of the system with respect to dissociation into a H2 molecule and a positronium negative ion, Ps−. The first predictions are made for positronic bonding in dianions consisting of molecular anionic fragments, specifically for (CN) 2 2 − and (NCO) 2 2 − . In all cases, we find that the molecules formed by the creation of a positronic bond are stable relative to dissociation into A− and e+A− (positron bound to a single anion), with bond energies on the order of 1 eV and bond lengths on the order of several ångstroms. [ABSTRACT FROM AUTHOR]

A systematic review and meta-analysis of sputter yield data for xenon ions normally incident on graphite at energies below 2000 eV was undertaken to identify systematic errors, determine the best model parameter values to represent yield as a function of energy, quantify uncertainty, and determine if the data support differences in yields for different types of graphite. A critical examination of the 11 published data sets for high density graphite, pyrolytic graphite, and amorphous carbon showed that, in general, they were carefully controlled to minimize errors. The most significant quantifiable systematic errors were those caused by the neglect of doubly charged ions, chemical erosion, and the impact of secondary electron emission on ion flux measurements. The effects of gas uptake and outgassing on mass loss measurements and unrepresentative surface textures may have biased other experiments, but these effects could not be quantified. The semi-empirical Eckstein model for yield as a function of energy was fit to data for the three graphite types using a hierarchical Bayesian statistical model, producing recommended fit parameters and probability distributions representing uncertainty in yields. The results showed that differences in yield for high density graphite and pyrolytic graphite were not statistically significant. Apparent differences in yield for amorphous carbon disappeared when the single data set available for energies below 150 eV was corrected for reasonable values of double ion content. Recommended procedures to avoid systematic errors and additional experiments and modeling to fill in gaps in our understanding are included. [ABSTRACT FROM AUTHOR]

Despite the wide existence of vesicles in living cells as well as their important applications like drug delivery, the underlying mechanism of vesicle fusion/fission remains under debate. Classical models cannot fully explain recent observations in experiments and simulations. Here, we develop a constrained self-consistent field theory that allows tracking the shape evolution and free energy as a function of center-of-mass separation distance. Fusion and fission are described in a unified framework. Both the kinetic pathway and the mechanical response can be simultaneously captured. By taking vesicles formed by polyelectrolytes as a model system, we predict discontinuous transitions between the three morphologies: parent vesicle with a single cavity, hemifission/hemifusion, and two separated child vesicles, as a result of breaking topological isomorphism. With the increase in inter-vesicle repulsion, we observe a great reduction in the cleavage energy, indicating that vesicle fission can be achieved without hemifission, in good agreement with simulation results. The force–extension relationship elucidates typical plasticity for separating two vesicles. The super extensibility in the mechanical response of vesicle is in stark contrast to soft particles with other morphologies, such as cylinder and sphere. Our work elucidates the fundamental physical chemistry based on intrinsic topological features of vesicle fusion/fission, which provides insights into various phenomena observed in experiments and simulations. [ABSTRACT FROM AUTHOR]

We present a derivation of the screening length for a solution containing a charge-regulated macroion, e.g. protein, with its counterions. We show that it can be obtained directly from the second derivatives of the total free energy by taking recourse to the "uncertainty relation" of the Legendre transform, which connects the Hessians or the local curvatures of the free energy as a function of density and its Legendre transform, i.e., osmotic pressure, as a function of chemical potentials. Based on the Fowler–Guggenheim–Frumkin model of charge regulation, we then analyze the "screening resonance" and the "overscreening" of the screening properties of the charge-regulated macroion solution. [ABSTRACT FROM AUTHOR]

We investigate two limits in open-shell diradical systems: O3, in which the interesting orbitals are in close proximity to one another, and (C21H13)2, where there is a significant spatial separation between the two orbitals. In accord with earlier calculations, we find that standard density-functional approximations do not predict the open-shell character for the former case but uniformly predict the open-shell character for the latter case. We trace the qualitatively incorrect behavior in O3 predicted by these standard density functional approximations to self-interaction error and use the Fermi–Löwdin-orbital-self-interaction-corrected formalism to determine accurate triplet, closed-shell singlet, and open-shell broken-spin-symmetry electronic configurations. Analysis of the resulting many-electron overlap matrices allows us to unambiguously show that the broken-spin-symmetry configurations do not participate in the representation of the Ms = 0 triplet states and allows us to reliably extract the singlet–triplet splitting in O3 by analyzing the energy as a function of Fermi-orbital-descriptor permutations. The results of these analyses predict the percentage of open-shell character in O3, which agrees well with conventional wavefunction-based methods. While these techniques are expected to be required in cases near the Coulson–Fischer point, we find that they will be less necessary in diradical systems with well-separated electrons, such as (C21H13)2. Results based on energies from self-interaction-corrected generalized gradient, local density, and Hartree–Fock approximations and experimental results are in generally good agreement for O3. These results help form the basis for deriving extended Heisenberg-like Hamiltonians that are needed for descriptions of molecular magnets when there are competing low-energy electronic configurations. [ABSTRACT FROM AUTHOR]

We report threshold collision induced dissociation experiments on protonated water clusters thermalized at low temperature for sizes n = 19–23. Fragmentation cross sections are recorded as a function of the collision energy and analyzed with a statistical model. This model allows us to account for dissociation cascades and provides values for the dissociation energies of each cluster. These values, averaging around 0.47 eV, are in good agreement with theoretical predictions at various levels of theory. Furthermore, the dissociation energies show a trend for the n = 21 magic and n = 22 anti-magic numbers relative to their neighbours, which is also in agreement with theory. These results provide further evidence to resolve the disagreement between previously published experimental values. A careful quantitative treatment of cascade dissociation in this model introduces interdependence between the dissociation energies of neighboring sizes, which reduces the number of free fitting parameters and improves both reliability and uncertainties on absolute dissociation energies deduced from experiments. [ABSTRACT FROM AUTHOR]

This work deals with a three-component chemotaxis system u t = Δ u - ∇ · (u χ 1 (w) ∇ w) + w - μ 1 u 2 , x ∈ Ω , t > 0 , v t = Δ v - ∇ · (v χ 2 (w) ∇ w) + w + r u v - μ 2 v 2 , x ∈ Ω , t > 0 , w t = Δ w + u + v - w , x ∈ Ω , t > 0 , describing the spatiotemporal Alopecia Areata dynamics with signal-dependent sensitivity under homogeneous Neumann boundary conditions in a smoothly bounded domain Ω ⊂ R n (n ≥ 1) , where the parameters μ 1 , μ 2 , r are positive constants. The chemotactic function χ i (w) (i = 1 , 2) is smooth and satisfying some conditions. Given suitably regular initial data, it is shown that the corresponding initial-boundary value problem admits a unique global bounded classical solution. Furthermore, by constructing the appropriate energy function, it is proved that the unique coexistence equilibrium is globally convergent in a specific parameter regime. These results generalize and improve some well-known results in the literature. [ABSTRACT FROM AUTHOR]

Tiller number and effective panicle number are important factors affecting rice yield. In this study, the sequencing data of 331 rice varieties were used to carry out genome‐wide association study (GWAS) of these two factors. A total of 58 candidate genes related to tiller number were identified, and their functions involved energy metabolism and cytoplasmic membrane metabolism pathways. There were 19 candidate genes related to effective panicle number, whose functions involved energy metabolism, cytoplasmic membrane metabolism and signal transduction pathways. A new QTL 'qTNP12', which controls both tiller number and effective panicle number, was identified on chromosome 12. There was specific variation in the 275th amino acid in the coding frame of the candidate gene. Indica rice with multiple tillers had histidine variation, while japonica rice with few tillers and Oryza rufipogon had arginine variation. Evolutionary analysis showed that the multi‐tiller trait of indica rice was developed through artificial selection and domestication. The results of this study provide a foundation for further clarifying the molecular mechanism of qTPN12 regulating tiller and effective panicle, as well as improving rice architecture through molecular marker‐assisted selection. [ABSTRACT FROM AUTHOR]

We present the governing equation and study vibrations of multiple crack beams undergoing large deflections subject to transverse loads. First, the primary motion equation is derived using Hamilton's principle applied to energy functions accounting for cracks. Then we derive a normalized equation governing the vibration of the extensible cracked beam. Single and multiple crack beam examples are considered and analyzed numerically to verify the validity of the derived equations. We propose a modified cracked extensible beam model accounting for the axial force by considering the reduced cross-sectional area. It is expressed by a new reduction parameter. Using the proposed model, we numerically investigate how the cracked extensible beam's natural frequencies change depending on various model parameters. [ABSTRACT FROM AUTHOR]

In this paper, we study and exactly solve the modified Dirac oscillator in curved spacetime with spin and pseudospin symmetries using an algebraic approach. Moreover, we focus on the radial part of this problem and apply the Schrödinger factorization method to demonstrate that the system possesses an SU(1, 1) symmetry. From this, we derive the wave functions and their respective energy spectrum. Additionally, we compute the radial coherent states of the modified Dirac oscillator and examine their temporal evolution in the spin and pseudospin limits, respectively. [ABSTRACT FROM AUTHOR]

External electric and mechanical stimuli can induce shape deformation in excitable media because of its intrinsic flexible property. When the signals propagation in the media is described by a neural network, creation of heterogeneity or defect is considered as the effect of shape deformation due to accumulation or release of energy in the media. In this paper, a temperature-light sensitive neuron model is developed from a nonlinear circuit composed of a phototube and a thermistor, and the physical energy is kept in capacitive and inductive terms. Furthermore, the Hamilton energy for this function neuron is obtained in theoretical way. A regular neural network is built on a square array by activating electric synapse between adjacent neurons, and a few of neurons in local area is excited by noisy disturbance, which induces local energy diversity, and continuous coupling enables energy propagation and diffusion. Initially, the Hamilton energy function for a temperature-light sensitive neuron can be obtained. Then, the finite neurons are applied noise to obtain energy diversity to explore the energy spread between neurons in the network. For keeping local energy balance, one intrinsic parameter is regulated adaptively until energy diversity in this local area is decreased greatly. Regular pattern formation indicates that local energy balance creates heterogeneity or defects and a few of neurons show continuous parameter shift for keeping energy balance in a local area, which supports gradient energy distribution for propagating waves in the network. [ABSTRACT FROM AUTHOR]

We study the strict convexity of the energy function of harmonic maps at their critical points from a Riemann surface to a Riemann surface, or to the product of negatively curved surfaces. When the target is a Riemann surface and when the map is of nonzero degree, we obtain a precise formula for the second derivative of the energy function along a Weil–Petersson geodesic, which implies that the energy function is strictly convex at its critical points. When the target is the product of two surfaces where each projection of the harmonic map is homotopic to a covering map, we also prove the strict convexity of the associated energy function. As an application we prove that the energy function has a unique critical point in these cases. [ABSTRACT FROM AUTHOR]

The internal energy, U, enthalpy, H, Helmholtz free energy, A, and Gibbs free energy, G, for the isothermal, isobaric, isochoric and isoentropic ensembles for polyethylene (PE) have been determined over a range of temperature, including the zero Kelvin, using the intrinsic equation of states based on the pressure-volume-temperature-entropy equations of state, P-V-T-S Eos determined in our previous reports. Each energy function was separated into its two parts; the energy = (the energy- the energy (0 K)) and the energy (0 K) where the energy (0 K) is the energy at the zero Kelvin. The energy (0 K) was much larger than the former, (the energy- the energy (0 K)), for the internal energy in the isobaric ensemble, the enthalpy in the isothermal, isochoric and isoentropic ensembles and the Gibbs free energy in the isothermal, isochoric and isoentropic ensembles, while the energy (0 K) was negligibly small for the internal energy in the isothermal ensemble and the Helmholtz free energy in the isothermal and isoentropic ensembles. The energy derivatives intrinsic to each ensemble, such as ( ∂ U ∂ T ) P , ( ∂ H ∂ T ) V , ( ∂ A ∂ V ) S , ( ∂ G ∂ P ) S , were evaluated where the subscripts, P, V, S, mean the isobaric, the isochoric and the isoentropic ensembles, respectively. [ABSTRACT FROM AUTHOR]

The influence of a tensile stress on the thermodynamics of martensitic transformations in polycrystalline samples has been studied. The presentation of a thermodynamic framework from the principles of thermodynamics allowed the calculation of frictional work and stored elastic energy as functions of applied stress. The framework was used to analyze the martensitic transformations of a sputter-deposited Ni 46.3 Ti 51.5 Co 2.2 (at. pct) thin film, with a microstructure characterized by Guinier–Preston zones and oriented Ti 2 Ni precipitates inside grains. From experimental results of thermal cycles at different constant stresses, frictional work and stored elastic energy were calculated. The frictional work showed a constant behavior with applied stress in both B2 ↔ R and R ↔ B19' transformations in the analyzed stress range. The stored elastic energy showed a decreasing behavior with applied stress in the B2 ↔ R transformation, and a constant behavior in the R ↔ B19' transformation. It was found that the temperature interval of martensitic transformations is no longer an indicator of the stored elastic energy magnitude when a tensile stress is applied. The observed decrease of the thermal hysteresis as the applied stress increases was analyzed in terms of the stored elastic energy dissipation. Complementary, the utilization of a Clausius–Clapeyron-like equation in polycrystalline alloys has been discussed. [ABSTRACT FROM AUTHOR]

In this paper, we study the multiplicity of normalized solutions to a class of nonlinear fractional Schrödinger–Poisson systems with Hardy potential. First, by using some ideas of the fountain theorem, we define a sequence of minimax values, and then we prove that these minimax values are critical values of the energy function restricted to a constraint set, which leads to the multiplicity of normalized solutions and extends some related results. [ABSTRACT FROM AUTHOR]

The influence of tachyonic instability on the Schwinger effect is investigated by axial coupling in the natural single‐field inflation model when strong back‐reaction exists in two parts. First, the Schwinger effect is considered when the conformal invariance of Maxwell action should be broken by axial coupling I(ϕ)FμνF∼μν$ I(\phi)F_{\mu \nu }\tilde{F}^{\mu \nu }$ with the inflaton field by identifying the standard horizon scale k=aH$ k=aH$ at the very beginning of inflation for additional boundary term and use several values of coupling constant χ1$ \chi _{1}$ and estimate electric and magnetic energy densities and energy density of produced charged particles due to the Schwinger effect. It has been found that for both coupling functions the energy density of the produced charged particles due to the Schwinger effect is so high and spoils inflaton field. In fact the strong coupling or back‐reaction occurs because the energy density of produced charged particles is exceeding of inflaton field. Two coupling functions are used to break conformal invariance of maxwell action. The simplest coupling function Iϕ=χ1ϕMp$ I\left(\phi \right)=\chi _{1}\frac{\phi }{M_{p}}$ and a curvature based coupling function Iϕ=12χ1e23ϕMp13Mp24Vϕ+23MpdVdϕ$ I\left(\phi \right)= 12\chi _{1}e^{\left(\sqrt {\frac{2}{3}}\frac{\phi }{M_{p}}\right)}\left[\frac{1}{3M_{p}^{2}}\left(4V\left(\phi \right)\right)+\frac{\sqrt {2}}{\sqrt {3}M_{p}}\left(\frac{dV}{d\phi }\right)\right]$ where Vϕ$V\left(\phi \right)$ is the potential of natural inflation. In second part, in oder to avoid strong back‐reaction problem, the horizon scale kH=aH|ζ|,ζ=I′ϕϕ̇H$ k_{H}=aH|\zeta |, \zeta =\frac{{I}^{\prime }\left(\phi \right)\dot{\phi }}{H}$ is identified in which a given Fourier begins to become tachyonically unstable.The influence of this scale is reducing the value of coupling constant χ1$ \chi _{1}$ and weakening the back‐reaction problem but in both cases strong coupling or strong back‐reaction exists and the Schwinger effect is impossible. Therefore, the Schwinger effect in this model is not possible and spoils inflation. Instantly, the Schwinger effect produces very high energy density of charged particles which causes back‐reaction problem and spoils inflaton field. It has been stressed that due to existence of strong back‐reaction in two cases the energy density of the produced charged particles due to the Schwinger effect spoils inflation. The influence of tachyonic instability in this model is quiet different from our published work in Kamarpour. In Kamarpour, this effect appears by vanishing of electromagnetic energy density and the energy density of charged particles at the very beginning of inflation. [ABSTRACT FROM AUTHOR]

Exploring high‐performance catalysts for hydrogen storage in magnesium hydride (MgH2) is crucial but still a challenge. Herein, Nb2CTx with controllable surface termination groups is developed as an efficient catalyst and the bifunctional modulation (adsorption energy and work function) of different surface termination groups (F, O, OH, or defects) is explored. First, compared to F and O, the introduction of OH on the surface or the direct removal of functional groups both leads to a significant increase in the adsorption of H by Nb2CTx. Second, compared to the surface bare, OH‐rich Nb2CTx has a lower work function, making it easier for hydrogen to enter Mg/MgH2 from the Nb2CTx surface or escape from the Mg/MgH2 surface into the Nb2CTx, thus facilitating the hydrogen ad/desorption properties of MgH2, i.e., the rate‐determining step (RDS) shifts from penetration to diffusion. The Nb2CTx‐KOH‐catalyzed MgH2 with optimal surface termination groups, therefore exhibits a release of 6.56 wt.% H2 in 5 min at 250 °C, and 6.46 wt.% H2 uptake within 5 min at 150 °C. The dehydrogenation and hydrogen uptake activation energies show 49.5% and 60.1% enhancements over pristine MgH2. In addition, a storage capacity of 5.51 wt.% is maintained after 50 dehydrogenation/hydrogenation cycles. [ABSTRACT FROM AUTHOR]

We employed two compelling and distinct methods, Fourier Transform Infrared Spectroscopy (FTIR) and Ramped Pyrolysis Oxidation (Ramped PyrOx), to examine the quality of organic matter (OM) stored in four peatlands located along a latitudinal gradient (Tropical (4˚N), Subtropical (27˚N), Boreal (48˚N), and Polar (68˚N)). FTIR was used to quantify the relative abundance of carbohydrates, a relatively labile compound class, and aromatics, which are more recalcitrant, in a sample set of four peat cores. These samples were then prepared using Ramped PyrOx, a second, independent method of determining OM quality that mimics the natural diagenetic maturation of OM that would take place over long timescales. Previous large-scale studies using FTIR to evaluate OM quality have observed that it generally increases with increasing latitude (more carbohydrates, less aromatics). Here, we demonstrate that the Ramped PyrOx approach both validates and complements the FTIR approach. The data stemming from each Ramped PyrOx preparation was input to a model that generates an estimated probability density function of the activation energy (E) required to break the C bonds in the sample. We separated these functions into three fractions ("low E," "medium E," and "high E") to create Ramped PyrOx variables that could be quantitatively compared to the compound class abundance data from FTIR. In assessing the agreement between the two methods, we found three significant relationships between Ramped PyrOx and FTIR variables. Low E fractions and carbohydrate content were positively correlated (R2 = 0.51) while low E fractions were negatively correlated with aromatic content (R2 = 0.58). Medium E fractions were found to be positively correlated with aromatics (R2 = 0.69). [ABSTRACT FROM AUTHOR]

Enhanced electronic coupling gives rise to many intriguing properties in π–d conjugated metal–organic frameworks (CMOFs). By low-temperature scanning tunneling microscopy and density functional theory calculation, we investigate the electronic coupling in one-dimensional (1D) π–d conjugated FeQDI polymers. Our experiments have resolved the bulk and end states stemming from Fe atoms in different coordination environments and their spatial extension due to π–d conjugation. By fitting the band structure by Wannier functions in an energy range of −0.5 eV to 0 eV, the Fe–Fe, QDI–QDI and Fe–QDI hopping integrals are determined to be 15 meV, 121 meV and 24 meV, respectively. Our work provides experimental and theoretical insights into the electronic coupling in 1D CMOFs. [ABSTRACT FROM AUTHOR]

The present study fabricated samples of polyurethane elastomers (PUEs) with three distinct densities and assessed their mechanical responses using split Hopkinson pressure bar (SHPB) tests. The findings reveal a significant increase in PUE stress with increasing strain rate and density. To further investigate the influence of strain rate sensitivity on PUEs, a strain rate sensitivity coefficient was employed to quantify the impact of strain rate on the mechanical properties of PUEs. Separate quantifications were performed for collapse stress, plateau stress, and densification strain as indicators of the strain rate sensitivity coefficient. The results demonstrate that the collapse stress sensitivity coefficient was notably affected by the applied strain rate. Additionally, both collapse and plateau stresses exhibited an increase with increasing density, which could be described by a power function relationship. Based on the theory of strain energy function, a constitutive model considering density and strain rate effects was developed to describe the stress–strain behavior of PUEs under various densities and strain rates. A comparison between this constitutive relationship and experimental results showed good agreement, highlighting its potential in describing dynamic mechanical behavior. [ABSTRACT FROM AUTHOR]

Highly accurate active contour models are widely used in various image segmentation methods. In this paper, we propose an image segmentation model based on Hellinger distance for local region intensity fitting (HD-LRIF). The method defines two different metrics based on the Hellinger distance and constructs a new data fitting term to segment the image efficiently by minimizing the energy function. In addition, our method is independent of the initial contour and the segmentation results consistently obtain high accuracy. The experimental results show that the HD-LRIF model is far superior to state-of-the-art segmentation methods in terms of accuracy and efficiency. Specifically, it can effectively filter the noise interference, thus enhancing robustness and improving the accuracy of image segmentation in general. [ABSTRACT FROM AUTHOR]

The effect of the entrance channel and neutron shell closure (N = 126) on the pre-scission neutron emission of 212Rn is investigated using available experimental data from EXFOR and theoretical calculations. It is found that the entrance channel plays a vital role in nuclear dissipation. Further, shell closure effects on neutron emission are also investigated as a function of excitation energy and its dependence on the entrance channel. Our study on the effects of entrance channel mass asymmetry (α) shows that the pre-scission neutron multiplicity (νpre) changes when the projectile and target combine to form the same compound nucleus (CN), which is shell closed. In addition, we have observed variations in the νpre when calculating the N/Z ratio near the shell closure which has not been observed. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of the entrance channel and neutron shell closure (N = 126) on the pre-scission neutron emission of 212Rn is investigated using available experimental data from EXFOR and theoretical calculations. It is found that the entrance channel plays a vital role in nuclear dissipation. Further, shell closure effects on neutron emission are also investigated as a function of excitation energy and its dependence on the entrance channel. Our study on the effects of entrance channel mass asymmetry (α) shows that the pre-scission neutron multiplicity (νpre) changes when the projectile and target combine to form the same compound nucleus (CN), which is shell closed. In addition, we have observed variations in the νpre when calculating the N/Z ratio near the shell closure which has not been observed. [ABSTRACT FROM AUTHOR]

This study proposes a method for calculating hyperelastic materials' stress and tangent modulus using a generalized complex-step derivative approximation. This method is accurate and requires only the operational code of the strain energy density function. Moreover, because it uses only standard complex operations in Fortran, no prior preparation is required, making the method convenient and practical. The effectiveness of the method was confirmed by applying it to the implementation of isotropic and anisotropic hyperelastic models. [ABSTRACT FROM AUTHOR]

Let x be an isometric immersion of a Riemannian n‐manifold M into a Euclidean (n + 1)‐space En+1 which does not pass through the origin of En+1. Then, the tangential part of the position vector field x of x is called the canonical vector field, and the normal part gives rise to a scalar function called the support function. Using the canonical vector field, support function, and mean curvature, we establish three new characterizations of hyperspheres. In addition, we prove that if the energy function of M satisfies the static perfect fluid equation, then M has at most two distinct principal curvatures. As an application, we prove that a complete noncompact hypersurface M is a spherical hypercylinder if the energy function of M satisfies the static perfect fluid equation, and it has exactly two distinct nonsimple principal curvatures. [ABSTRACT FROM AUTHOR]

With the deepening of national efforts toward green energy transformation, the power system is evolving into one characterized by "double high"—a high proportion of new energy integration and a high level of power electronic systems. This results in a more complex system topology, necessitating improvements in various prevention and control measures. Traditional model-based methods for locating power oscillation disturbance sources in power systems are no longer sufficient to meet the operational demands of modern power systems. With the rapid development of wide-area measurement systems (WAMS), there is growing interest in disturbance source localization using system response data. System dynamics provide a wealth of easily extractable data that can accurately reflect the power system's behavior under normal conditions. This paper proposes a numerical method for locating disturbance sources, combining energy functions with normal distribution identification, based on power oscillation mechanisms and system response data. The method identifies potential disturbance sources, including small random load fluctuations and large forced power oscillations. The innovation lies in the introduction of a 3 Sigma value criterion to pinpoint the disturbance source location, addressing the limitations of traditional energy function methods that require manual intervention. By quantifying the localization of power oscillation disturbance sources, this method significantly improves both efficiency and accuracy. [ABSTRACT FROM AUTHOR]

To reduce errors in sub-synchronous oscillation (SSO) modal identification and improve the accuracy and noise resistance of the traditional Prony algorithm, this paper focuses on SSOs caused by the integration of doubly fed induction generators (DFIGs) with series compensation into the grid. A novel SSO modal identification method based on the hippopotamus optimization–variational mode decomposition (HO-VMD) and singular value decomposition–regularized total least squares–Prony (SVD-RTLS-Prony) algorithms is proposed. First, the energy ratio function is used for real-time monitoring of the system to identify oscillation signals. Then, to address the limitations of the VMD algorithm, the HO algorithm's excellent optimization capabilities were utilized to improve the VMD algorithm, leading to preliminary denoising. Finally, the SVD-RTLS-improved Prony algorithm was employed to further suppress noise interference and extract oscillation characteristics, allowing for the accurate identification of SSO modes. The performance of the proposed method was evaluated using theoretical and practical models on the Matlab and PSCAD simulation platforms. The results indicate that the algorithms effectively perform denoising and accurately identify the characteristics of SSO signals, confirming its effectiveness, accuracy, superiority, and robustness against interference. [ABSTRACT FROM AUTHOR]

ABSTRACT The advantages of constitutive models in energy‐conservation frameworks have been widely addressed in the literature. A key component is choosing an appropriate energy potential to derive the hyperelastic constitutive equations. This article investigates the advantages and limitations of different energy potentials found in the literature based on mathematical conditions to guarantee numerical stability, such as the desired order of homogeneity, positive and non‐singular stiffness within the application range, and equivalent Poisson's ratio from a constitutive modelling standpoint. Potentials meeting the aforementioned criteria are employed to simulate the response envelopes of Karlsruhe fine sand (KFS). Moreover, the performance of the potentials, in conjunction with plasticity theories, is examined. To achieve this, the hyperelastic constitutive equations have been coupled with the bounding surface plasticity model of Dafalias and Manzari to reproduce the soil response in a hyperelastic–plastic frame. Finally, one of the potentials is modified, whereas recommendations for incorporating other appropriate free energy functions into different soil constitutive models are presented. Furthermore, 100 closed elastic strain cycles have been simulated with the bounding surface plasticity model of Dafalias and Manzari considering the original hypoelastic stiffness and hyperelastic–plastic constitutive equations. Using the hypoelastic framework in the simulation led to stress accumulation after 100 closed elastic strain loops, while a reversible response was predicted using the hyperelastic stiffness tensor. [ABSTRACT FROM AUTHOR]

The classic interactive image segmentation algorithm GrabCut achieves segmentation through iterative optimization. However, GrabCut requires multiple iterations, resulting in slower performance. Moreover, relying solely on a rectangular bounding box can sometimes lead to inaccuracies, especially when dealing with complex shapes or intricate object boundaries. To address these issues in GrabCut, an improvement is introduced by incorporating appearance overlap terms to optimize segmentation energy function, thereby achieving optimal segmentation results in a single iteration. This enhancement significantly reduces computational costs while improving the overall segmentation speed without compromising accuracy. Additionally, users can directly provide seed points on the image to more accurately indicate foreground and background regions, rather than relying solely on a bounding box. This interactive approach not only enhances the algorithm's ability to accurately segment complex objects but also simplifies the user experience. We evaluate the experimental results through qualitative and quantitative analysis. In qualitative analysis, improvements in segmentation accuracy are visibly demonstrated through segmented images and residual segmentation results. In quantitative analysis, the improved algorithm outperforms GrabCut and min_cut algorithms in processing speed. When dealing with scenes where complex objects or foreground objects are very similar to the background, the improved algorithm will display more stable segmentation results. [ABSTRACT FROM AUTHOR]

Image triangulation methods, which decompose an image into a series of triangles, are fundamental in artistic creation and image processing. This paper introduces a novel framework that integrates cubic Bézier curves into image triangulation, enabling the precise reconstruction of curved image features. Our developed framework constructs a well‐structured curved triangle mesh, effectively preventing overlaps between curves. A refined energy function, grounded in differentiable rendering, establishes a direct link between mesh geometry and rendering effects and is instrumental in guiding the curved mesh generation. Additionally, we derive an explicit gradient formula with respect to mesh parameters, facilitating the adaptive and efficient optimization of these parameters to fully leverage the capabilities of cubic Bézier curves. Through experimental and comparative analyses with state‐of‐the‐art methods, our approach demonstrates a significant enhancement in both numerical accuracy and visual quality. [ABSTRACT FROM AUTHOR]

In this paper, optimal growth analysis of spatial disturbances in round submerged jets is performed. Optimal energy growth is studied for various Reynolds numbers Re and frequencies ω. Different velocity profiles proposed by Michalke ["Survey on jet instability theory," Prog. Aerosp. Sci. 21, 159–199 (1984)] are investigated by varying the shear layer momentum thickness δ, while the jet radius R is considered fixed (as characteristic length). In the case of stationary disturbances, there are no amplified eigenmodes, so eventually the energy of such disturbances decays downstream. Such disturbances are characterized by optimal energy growth as a function of streamwise coordinate z. At certain location downstream zmax this value reaches its maximum Gmax and then decays, although not monotonically, unlike the result of the temporary setting [Jimenez-Gonzalez et al., "Modal and non-modal evolution of perturbations for parallel round jets," Phys. Fluids 27, 044105 (2015); Jimenez-Gonzalez and Brancher, "Transient energy growth of optimal streaks in parallel round jets," Phys. Fluids 29, 114101 (2017)]. The well-known scaling G max ∝ Re 2 and z max ∝ Re is confirmed for stationary disturbances. Conversely, for nonstationary disturbances there is a range of frequencies in which an amplified mode is present. In this case, optimal perturbations far downstream consist only of the amplified mode. The main effect of non-modality here is "the energy pumping" of the amplified mode, so the disturbances are characterized by the "energy ratio" G / E m , i.e., the ratio of the energy of an arbitrary perturbation to the energy of the amplified mode. The influence of the shear layer momentum thickness on optimal disturbances is studied; increasing the shear layer momentum thickness of the base flow "smears" the area occupied by the optimal disturbance, although it does not dramatically affect energy gain values, slightly decreasing maximum energy as shear layer momentum thickness increases. Spatial oscillations in the energy of stationary optimal disturbances in jet flows are discovered. The spectrum structure examination shows that the frequency of these oscillations corresponds to the frequencies of the two least damped discrete eigenmodes. [ABSTRACT FROM AUTHOR]

Context: Accurate functions to analytically represent the potential energy interactions of CO + diatomic system in X 2 Σ + , A 2 Π , and B 2 Σ + electronic states are proposed. The new functions depend upon only four parameters directly obtained from experimental data, without any fitting procedure. These functions have been developed from the modified generalized potential proposed by Araújo and Ballester. The function for the X 2 Σ + electronic state represents a significant improvement to the previously proposed model. To quantify the accuracy of the potential energy functions, the Lippincont test is used. The novel potential was also compared with the classical Morse potential and with the recently proposed Improved Generalized Pöschl-Teller potential. Furthermore, the main spectroscopic constants and vibrational energy levels are calculated and compared for all potentials. The present results agree excellently with the experiment Rydberg-Klein-Rees (RKR) potentials. Methods: The rovibrational energy levels of the proposed diatomic potentials were asserted by solving radial the Schrödinger equation of the nuclear motion with the aid of the LEVEL program. [ABSTRACT FROM AUTHOR]

The leave-one-out (LOO) green fluorescent protein (GFP) approach to biosensor design combines computational protein design with split protein reconstitution. LOO-GFPs reversibly fold and gain fluorescence upon encountering the target peptide, which can be redefined by computational design of the LOO site. Such an approach can be used to create reusable biosensors for the early detection of emerging biological threats. Enlightening biophysical inferences for nine LOO-GFP biosensor libraries are presented, with target sequences from dengue, influenza, or HIV, replacing beta strands 7, 8, or 11. An initially low hit rate was traced to components of the energy function, manifesting in the over-rewarding of over-tight side chain packing. Also, screening by colony picking required a low library complexity, but designing a biosensor against a peptide of at least 12 residues requires a high-complexity library. This double-bind was solved using a "piecemeal" iterative design strategy. Also, designed LOO-GFPs fluoresced in the unbound state due to unwanted dimerization, but this was solved by fusing a fully functional prototype LOO-GFP to a fiber-forming protein, Drosophila ultrabithorax, creating a biosensor fiber. One influenza hemagglutinin biosensor is characterized here in detail, showing a shifted excitation/emission spectrum, a micromolar affinity for the target peptide, and an unexpected photo-switching ability. [ABSTRACT FROM AUTHOR]

In the production of high-definition maps, it is necessary to achieve the three-dimensional instantiation of road furniture that is difficult to depict on traditional maps. The development of mobile laser measurement technology provides a new means for acquiring road furniture data. To address the issue of traffic marking extraction accuracy in practical production, which is affected by degradation, occlusion, and non-standard variations, this paper proposes a 3D reconstruction method based on energy functions and template matching, using zebra crossings in vehicle-mounted LiDAR point clouds as an example. First, regions of interest (RoIs) containing zebra crossings are obtained through manual selection. Candidate point sets are then obtained at fixed distances, and their neighborhood intensity features are calculated to determine the number of zebra stripes using non-maximum suppression. Next, the slice intensity feature of each zebra stripe is calculated, followed by outlier filtering to determine the optimized length. Finally, a matching template is selected, and an energy function composed of the average intensity of the point cloud within the template, the intensity information entropy, and the intensity gradient at the template boundary is constructed. The 3D reconstruction result is obtained by solving the energy function, performing mode statistics, and normalization. This method enables the complete 3D reconstruction of zebra stripes within the RoI, maintaining an average planar corner accuracy within 0.05 m and an elevation accuracy within 0.02 m. The matching and reconstruction time does not exceed 1 s, and it has been applied in practical production. [ABSTRACT FROM AUTHOR]

To generate spatial layouts for spaces with public service functions such as cultural and exhibition halls, urban reading spaces, supermarkets, etc., this paper proposed a spatial layout expression method. To address the expressive requirements of diverse spatial layouts, the method recorded layout information in a hierarchical graph structure. Subsequently, it populated the appropriate layout objects as the initial state according to the graph structure. By employing a spatial layout energy function and movement strategies, it introduced the Metropolis-Hastings algorithm for optimization, resulting in suitable layout schemes. It demonstrated the effectiveness of the method through testing across various application scenarios, validating its performance. Following principles of public space design, it proposed safety evaluation indicators to compare the performance of different methods. The results indicate that the proposed method exhibits better performance in layout efficiency and computational effectiveness, making it applicable to various types of public space layouts. [ABSTRACT FROM AUTHOR]

In this paper, we construct Young wall models for the level 1 highest weight and Fock space crystals of quantum affine algebras in types E 6 (2) and F 4 (1) . Our starting point in each case is a combinatorial realization for a certain level 1 perfect crystal in terms of Young columns. Then, using energy functions and affine energy functions we define the notions of reduced and proper Young walls, which model the highest weight and Fock space crystals, respectively. [ABSTRACT FROM AUTHOR]

With the help of path realization and affine energy function, we give a Young wall construction of level-1 highest weight crystals B (λ) over U q (G 2 (1)) and U q (D 4 (3)). Our construction is based on four different shapes of colored blocks, O -block, I -block, L -block and LL -block, obtained by cutting the unit cube in three different ways. [ABSTRACT FROM AUTHOR]

Aiming at the problem of irregular waveform of nonrectangular wave voltage sags, the least square method is proposed to fit the nonrectangular wave voltage sags. Based on the fitting curve, the severity of nonrectangular wave voltage sag is assessed from load side and power grid side respectively. The proposed method improves the accuracy of nonrectangular voltage sag severity assessment. Firstly, the least square fitting method is used to fit the nonrectangular wave voltage sag. Secondly, the nonrectangular wave's amplitude and duration are used to generate a rectangular wave. The weight function method is used to assess the severity of the rectangular wave voltage sags. According to the area proportion of nonrectangular wave in rectangular wave, the severity of nonrectangular wave voltage sags from the equipment side is assessed. Concurrently, combined with the fitted nonrectangular wave mathematical model, the energy index function is used to assess the severity of nonrectangular wave voltage sag from the power side. A MATLAB model of the IEEE33 node system is built, and the severity of nonrectangular wave voltage sags obtained by simulation is assessed. The results indicate that the voltage sag severity assessment method is simple and efficient in calculation. And the assessment method is easy to operate and implement in engineering, and has high engineering application value. [ABSTRACT FROM AUTHOR]