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Temporal coupled-mode theory (CMT) is an acclaimed and widely used theoretical framework for modeling the continuous-wave response and temporal dynamics of any integrated or free-space photonic resonant structure. It was initially employed to understand how energy is coupled into and out of a cavity and how it is exchanged between different resonant modes. In the 30 years that followed its establishment, CMT has been expanded to describe a broad range of nonlinear interactions as well (self- and cross-phase modulation, saturable absorption, frequency generation, gain, etc.). In this Tutorial, we thoroughly present the basic principles and the evolution of CMT throughout the years, showcasing its immense capabilities for the analysis and design of linear and nonlinear resonant photonic systems. Importantly, we focus on the examples of modern, open nanophotonic resonators incorporating contemporary bulk or sheet (2D) materials that may be lossy and dispersive. For each linear/nonlinear effect under study, we follow a meticulous, step-by-step approach, starting from an accurate model of the physical phenomenon and proceeding to its introduction in the CMT framework all the way to the efficient solution of the resulting system of equations. Our work highlights the merits of CMT as an efficient, accurate, and versatile theoretical tool. We envision that it can serve both as an introductory reference for any reader and as a comprehensive handbook on how to incorporate a broad range of linear and nonlinear effects in the CMT framework. [ABSTRACT FROM AUTHOR]

The vast majority of control schemes related to the sequential probability ratio test (SPRT) are designed for the purpose of monitoring only the process mean. Nonetheless, most manufacturing processes are vulnerable to external factors that cause the process mean and variability to change simultaneously. It is, therefore, crucial to consider a joint scheme for monitoring both the location and scale parameters of a production process. In this article, we develop a scheme that combines both mean and variance information in a single SPRT, known as the omnibus SPRT (OSPRT) chart. Expressions for the run-length properties of the OSPRT chart are derived by means of the Markov chain approach. We also propose optimal designs for the OSPRT chart based on two different metrics, i.e. by minimising the average time to signal and the average extra quadratic loss. Through a comprehensive analysis, this article reveals that the optimal OSPRT chart outperforms the classical $ \bar{X} $ X ¯ -S, weighted-loss cumulative sum, absolute-value SPRT, and two maximum weighted-moving-average-type charts. The optimal OSPRT chart also has the advantage of collecting a small number of samples on average before producing a decision. Finally, the implementation of the OSPRT chart is presented with a wire bonding industrial dataset. [ABSTRACT FROM AUTHOR]

In recent papers, Becke et al. [J. Chem. Phys. 158, 151103 (2023)] and then Becke [J. Chem. Phys. 159, 241101 (2023)] have developed a novel double hybrid density functional, "DH23," whose terms are based on good local physics. Its 12 coefficients are trained on the GMTKN55 (general main-group thermochemistry, kinetics, and noncovalent interactions) chemical database of Goerigk et al. [Phys. Chem. Chem. Phys. 19, 32184 (2017)]. The lowest GMTKN55 "WTMAD2" error to date for any hybrid or double hybrid density functional was obtained (1.73 kcal/mol for the revDH23 variant). Here, we simplify DH23 by introducing a dispersion damping scheme involving atomic numbers only and one global parameter. The resulting new functional, "DH24," performs as well as its predecessors. [ABSTRACT FROM AUTHOR]

In this work, the electromigration dispersion (EMD) due to the charged electrolytes in microchannels is considered without using the thin electrical double layer assumption. The electrokinetic flow and transport of ions are actuated within a rectangular micro-/nanochannel having a negative surface charge density under the influence of an external electric field. Due to the local variation of the conductivity and the nonvalidity of the electroneutrality condition, the local electric field varies as a function of the solute concentration, wall surface charge density, valency, and Debye layer length. The resulting electrokinetic flow due to the external electric field drives the fluid along with the charged species, where the Taylor–Aris dispersion separates the solutes into their different constituents. The local concentration dependence of the electric field leads to the formation of concentration profiles that are slightly asymmetric with respect to the standard Gaussian distribution. Including a finite Debye layer thickness has an effect on the advection of the species as well as the diffusion of the species. It is found that in cases where Debye layers are thicker, the species advects faster within the microchannel. This might give valuable insights into the nature of the EMD. Our model aims to predict the evolution of ionic concentration at all positions within the channel. A study of the higher-order statistics in skewness and kurtosis has also been conducted to obtain a better understanding of the idealized model consisting of a buffer solution. [ABSTRACT FROM AUTHOR]

In this study, we introduce SAPT10K, a comprehensive dataset comprising 9982 noncovalent interaction energies and their binding energy components (electrostatics, exchange, induction, and dispersion) for diverse intermolecular complexes of 944 unique dimers. These complexes cover significant portions of the intermolecular potential energy surface and were computed using higher-order symmetry-adapted perturbation theory, SAPT2+(3)(CCD), with a large aug-cc-pVTZ basis set. The dispersion energy values in SAPT10K serve as crucial inputs for refining the ab initio dispersion potentials based on Grimme's D3 and many-body dispersion (MBD) models. Additionally, Δ machine learning (ML) models based on newly developed intermolecular features, which are derived from intermolecular histograms of distances for element/substructure pairs to simultaneously account for local environments as well as long-range correlations, are also developed to address deficiencies of the D3/MBD models, including the inflexibility of their functional forms, the absence of MBD contributions in D3, and the standard Hirshfeld partitioning scheme used in MBD. The developed dispersion models can be applied to complexes involving a wide range of elements and charged monomers, surpassing other popular ML models, which are limited to systems with only neutral monomers and specific elements. The efficient D3-ML model, with Cartesian coordinates as the sole input, demonstrates promising results on a testing set comprising 6714 dimers, outperforming another popular ML model, component-based machine-learned intermolecular force field (CLIFF), by 1.5 times. These refined D3/MBD-ML models have the capability to replace the time-consuming dispersion components in symmetry-adapted perturbation theory-based calculations and can promptly illustrate the dispersion contribution in noncovalent complexes for supramolecular assembly and chemical reactions. [ABSTRACT FROM AUTHOR]

In this work, we utilize our recently developed machine learning (ML)-corrected ab initio dispersion (aiD) potential, known as D3-ML, which is based on the comprehensive SAPT10K dataset and relies solely on Cartesian coordinates as input, to address the dispersion deficiencies in second-order Møller−Plesset perturbation theory (MP2) by replacing its problematic dispersion and exchange-dispersion terms with D3-ML. This leads to the development of a new dispersion-corrected MP2 method, MP2+aiD(CCD), which outperforms other spin-component-scaled and dispersion-corrected MP2 methods as well as popular ML models for predicting noncovalent interactions across various datasets, including S66 × 8, NAP6 (containing 6 naphthalene dimers), L7, S12L, DNA−ellipticine, the C60 dimer, and C60[6]CPPA. In addition, MP2+aiD(CCD) exhibits comparable or even superior performance compared to the contemporary ωB97M-V functional. The limited performance of pure ML models for systems outside the training set or larger than those in the training set highlights their instability and unpredictability. Conversely, the outstanding performance and transferability of the hybrid MP2+aiD(CCD) method can be attributed to the fusion of the physical electronic structure method and a data-driven ML model, combining the strengths of both sides. This investigation firmly establishes MP2+aiD(CCD) as one of the most accurate and reliable fifth-order scaling correlated wave function methods currently available for modeling noncovalent interactions, even for large complexes. MP2+aiD(CCD) is expected to be reliably applicable in investigating real-life complexes at the hundred-atom scale. [ABSTRACT FROM AUTHOR]

Mexican-hat-shaped quartic dispersion manifests itself in certain families of single-layer two-dimensional hexagonal crystals such as compounds of groups III–VI and groups IV–V as well as elemental crystals of group V. A quartic band forms the valence band edge in various of these structures, and some of the experimentally confirmed structures are GaS, GaSe, InSe, SnSb, and blue phosphorene. Here, we numerically investigate strictly one-dimensional and quasi-one dimensional (Q1D) systems with quartic dispersion and systematically study the effects of Anderson disorder on their transport properties with the help of a minimal tight-binding model and Landauer formalism. We compare the analytical expression for the scaling function with simulation data to distinguish the domains of diffusion and localization regimes. In one dimension, it is shown that conductance drops dramatically at the quartic band edge compared to the quadratic case. As for the Q1D nanoribbons, a set of singularities emerge close to the band edge, suppressing conductance and leading to short mean-free-paths and localization lengths. Interestingly, wider nanoribbons can have shorter mean-free-paths because of denser singularities. However, the localization lengths sometimes follow different trends. Our results display the peculiar effects of quartic dispersion on transport in disordered systems. [ABSTRACT FROM AUTHOR]

The dispersion properties of the absorption coefficients [α(ν)] of different multi-component silicate oxide glasses have been studied in the frequency region below the boson peak by using THz-time-domain spectroscopy. The value of α(ν)/ν2 has been shown to exhibit a minimum level (R) at low frequency and subsequently a linear increase in the form of r(ν/νBP + E) with increasing frequency, where νBP is the boson peak frequency and R, r, and E are material-specific constants. It has also been found that R ∝ r and E is a constant common to most glasses. This α(ν)/ν2 behavior is ascribed to the dispersion property of the light-vibration coupling coefficient under the reasonable vibrational density of state function. The minimum (constant) and linear terms of the α(ν)/ν2 spectrum are originated from the physical/chemical disorder-induced charge fluctuations in the long-range scale (constant term) and short-range scale (linear term), respectively. The fluctuating charge (σ1) caused by uncorrelated, long-range disorders has primary significance for determining the sub-THz absorption dispersion properties, and its value has been determined for each glass material. [ABSTRACT FROM AUTHOR]

We report the dynamic characterization of the spin-torque-driven in-plane precession modes of a spin-torque nano-oscillator based on two different synthetic ferrimagnets: a pinned one characterized by a strong Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction, which is exchange-coupled to an antiferromagnetic layer; and a non-pinned one characterized by weak RKKY coupling. The microwave properties associated with the steady-state precession of both synthetic ferrimagnets (SyFs) are characterized by high spectral purity and power spectral density. However, frequency dispersion diagrams of the damped and spin-transfer torque modes reveal drastically different dynamical behavior and microwave emission properties in both SyFs. In particular, the weak coupling between the magnetic layers of the non-pinned SyF raises discontinuous dispersion diagrams suggesting a strong influence of mode crossing. An interpretation of the different dynamical features observed in the damped and spin-torque modes of both SyF systems was obtained by solving simultaneously, in a macrospin approach, a linearized version of the Landau–Lifshitz–Gilbert equation including the spin-transfer torque term. [ABSTRACT FROM AUTHOR]

The investigation of charge carrier transport in state-of-the-art nanoelectronic devices based on III/V semiconductors proves to be challenging, even more so when the highly non-parabolic energy dispersion exhibited by these materials is taken into account. Unlike the common approach of neglecting this behavior by the use of the parabolic band approximation, a novel combination of a tight-binding approach with a quantum Liouville-type equation is introduced here, where any arbitrary energy dispersion can effectively be included. This leads to a discretization based on the atomic structure without the need for finite difference approximations of the Hamiltonian. Because this allows for the stationary as well as the transient simulation of quantum charge carrier transport, it is well suited for the analysis of ultrathin FETs such as dual-gate FETs when it is combined with a mode-space approach. We demonstrate that the parabolic approximation not only vastly underestimates the current densities when compared to the non-parabolic case but also fails to capture transient effects such as gain compression when amplifier operation is considered. [ABSTRACT FROM AUTHOR]

We propose a Brownian ratchet for the unidirectional transport of stimuli-responsive molecules confined in a series of asymmetric geometries. It relies on repetitive cycles of aggregation and dispersion, which cause significant changes in molecular distribution within the confining geometry and enable the Brownian motion of the molecules to be ratcheted in a specific direction. To demonstrate the feasibility of the proposed Brownian ratchet, we conducted Brownian dynamics simulations where stimuli-responsive molecules were repeatedly aggregated and dispersed in a series of truncated conical tubes by altering intermolecular interactions. These simulations demonstrated the unidirectional transport of the molecules, indicating the efficacy of the proposed Brownian ratchet. Furthermore, we found that it becomes more effective with higher concentrations of molecules. This study suggests that, through the deliberate control of molecular assembly and disassembly by stimuli-responsive intermolecular interactions, it is possible to achieve directional and controlled molecular transport in various nanoscale applications. [ABSTRACT FROM AUTHOR]

During the last few years, patchy colloidal dispersions have emerged as ideal candidates of glass-formers of systems composed of particles that interact with non-isotropic potentials. However, from the computational point of view, the characterization of their dynamical properties close to the glass transition via any kind of molecular dynamics simulation technique can be very difficult due to the slowing down of both the rotational and translational dynamics. Although a plethora of dynamical techniques have been developed to account for the dynamics of patchy colloids, new and complementary simulation techniques are required to explore, much faster and more efficiently, the dynamical arrest transition of patchy colloidal dispersions when computer simulation consists of a large number of particles and, due to the slow particle dynamics at the glass transition, an extended time window is explicitly required. Then, in this contribution, by means of the so-called dynamic-Monte Carlo method, we report on the dynamical arrest transition, both rotational and translational, of a bidisperse patchy colloidal dispersion, following three different paths along the density-temperature plane, including high densities and low temperatures. Although this method has not been extensively tested at extreme thermodynamic conditions, we show that even at the dynamical arrest transition, it allows us to extract good dynamical data from a complex system. Therefore, it turns out to be a promising technique to explore the onset of vitrification of anisotropic colloidal particles. [ABSTRACT FROM AUTHOR]

The small-signal equivalent circuit of GaN-based self-switching diodes has been obtained, which apart from the intrinsic R ‖ C branch, generally used to describe the diode performance, needs new elements to describe the low-frequency dispersion of the impedance originated by the presence of surface and bulk traps. The proposed model allows us to reproduce not only the high-frequency results (extracted from S-parameter measurements in the 40 MHz–43.5 GHz range) at room temperature, but also the low-frequency impedance measurements (75 kHz–30 MHz) at cryogenic temperatures down to 70 K. These new elements are a self-inductance associated to the effect of surface states (typical of a device with a high surface-to-volume ratio) and an extra series R – C branch modeling the influence of the bulk traps. [ABSTRACT FROM AUTHOR]

Time-aging-time superposition and the concept of single-parameter aging refer to the experimentally verified scenario in which the relaxation profile is shifted as a whole along the logarithmic time or frequency scale during physical aging, i.e., without changing the shape of the susceptibility spectrum or decay function. This homogeneous aspect of aging and structural recovery appears to contrast the heterogeneous nature of structural relaxation in equilibrium. A picture is proposed in which both structural recovery and relaxation are heterogeneous, but lacking a local correlation of time constants. This scenario is consistent with time-aging-time superposition and single-parameter aging, as well as with recovery and relaxation processes being subject to practically the same time constant dispersion. [ABSTRACT FROM AUTHOR]

A thermally driven needle-like (NL) to distorted perovskite (DP) phase transition in SrZrS3 was investigated by means of ab initio free energy calculations accelerated by machine learning. As a first step, a systematic screening of the methods to include long-range interactions in semilocal density functional theory Perdew–Burke–Ernzerhof calculations was performed. Out of the ten correction schemes tested, the Tkatchenko–Scheffler method with iterative Hirshfeld partitioning method was found to yield the best match between calculated and experimental lattice geometries, while predicting the correct order of stability of NL and DP phases at zero temperature. This method was then used in free energy calculations, performed using several approaches, so as to determine the effect of various anharmonicity contributions, such as the anisotropic thermal lattice expansion or the thermally induced internal structure changes, on the phase transition temperature (TNP→DP). Accounting for the full anharmonicity by combining the NPT molecular dynamics data with thermodynamic integration with harmonic reference provided our best estimate of TNL→DP = 867 K. Although this result is ∼150 K lower than the experimental value, it still provides an improvement by nearly 300 K compared to the previous theoretical report by Koocher et al. [Inorg. Chem. 62, 11134–11141 (2023)]. [ABSTRACT FROM AUTHOR]

A model system of identical particles interacting via a hard-sphere potential is essential in condensed matter physics; it helps to understand in and out of equilibrium phenomena in complex fluids, such as colloidal dispersions. Yet, most of the fixed time-step algorithms to study the transport properties of those systems have drawbacks due to the mathematical nature of the interparticle potential. Because of this, mapping a hard-sphere potential onto a soft potential has been recently proposed [Báez et al., J. Chem. Phys. 149, 164907 (2018)]. More specifically, using the second virial coefficient criterion, one can set a route to estimate the parameters of the soft potential that accurately reproduces the thermodynamic properties of a monocomponent hard-sphere system. However, real colloidal dispersions are multicomponent or polydisperse, making it important to find an efficient way to extend the potential model for dealing with such kind of many-body systems. In this paper, we report on the extension and applicability of the second virial coefficient criterion to build a description that correctly captures the phenomenology of both multicomponent and polydisperse hard-sphere dispersions. To assess the accuracy of the continuous potentials, we compare the structure of soft polydisperse systems with their hard-core counterpart. We also contrast the structural and thermodynamic properties of soft binary mixtures with those obtained through mean-field approximations and the Ornstein–Zernike equation for the two-component hard-sphere dispersion. [ABSTRACT FROM AUTHOR]

Many-body dispersion (MBD) is a powerful framework to treat van der Waals (vdW) dispersion interactions in density-functional theory and related atomistic modeling methods. Several independent implementations of MBD with varying degree of functionality exist across a number of electronic structure codes, which both limits the current users of those codes and complicates dissemination of new variants of MBD. Here, we develop and document libMBD, a library implementation of MBD that is functionally complete, efficient, easy to integrate with any electronic structure code, and already integrated in FHI-aims, DFTB+, VASP, Q-Chem, CASTEP, and Quantum ESPRESSO. libMBD is written in modern Fortran with bindings to C and Python, uses MPI/ScaLAPACK for parallelization, and implements MBD for both finite and periodic systems, with analytical gradients with respect to all input parameters. The computational cost has asymptotic cubic scaling with system size, and evaluation of gradients only changes the prefactor of the scaling law, with libMBD exhibiting strong scaling up to 256 processor cores. Other MBD properties beyond energy and gradients can be calculated with libMBD, such as the charge-density polarization, first-order Coulomb correction, the dielectric function, or the order-by-order expansion of the energy in the dipole interaction. Calculations on supramolecular complexes with MBD-corrected electronic structure methods and a meta-review of previous applications of MBD demonstrate the broad applicability of the libMBD package to treat vdW interactions. [ABSTRACT FROM AUTHOR]

We derive and implement an alternative formulation of the Stochastic Lanczos algorithm to be employed in connection with the Many-Body Dispersion model (MBD). Indeed, this formulation, which is only possible due to the Stochastic Lanczos' reliance on matrix-vector products, introduces generalized dipoles and fields. These key quantities allow for a state-of-the-art treatment of periodic boundary conditions via the O (N log (N)) Smooth Particle Mesh Ewald (SPME) approach which uses efficient fast Fourier transforms. This SPME-Lanczos algorithm drastically outperforms the standard replica method which is affected by a slow and conditionally convergence rate that limits an efficient and reliable inclusion of long-range periodic boundary conditions interactions in many-body dispersion modelling. The proposed algorithm inherits the embarrassingly parallelism of the original Stochastic Lanczos scheme, thus opening up for a fully converged and efficient periodic boundary conditions treatment of MBD approaches. [ABSTRACT FROM AUTHOR]

Surface property modification of catalyst support is a straightforward approach to optimize the performance of supported noble metal catalysts. In particular, oxygen vacancies and hydroxyl groups play significant roles in promoting noble metal dispersion on catalysts as well as catalytic stability. In this study, we developed a nanoflower-like TiO2-supported Pd catalyst that has a higher concentration of oxygen vacancies and surface hydroxyl groups compared to that of commercial anatase and P25 support. Notably, due to the distinctive structure of the nanoflower-like TiO2, our catalyst exhibited improved dispersion and stabilization of Pd species and the formation of abundant reactive oxygen species, thereby facilitating the activation of CO and O2 molecules. As a result, the catalyst showed remarkable efficiency in catalyzing the low-temperature CO oxidation reaction with a complete CO conversion at 80 °C and stability for over 100 h. [ABSTRACT FROM AUTHOR]

The influence of fluctuating charges or charge flow on the dynamic linear response properties of isolated molecules from the TS42 database is evaluated, with particular emphasis on dipole polarizability and C6 dispersion coefficients. Two new descriptors are defined to quantify the charge-flow contribution to response properties, making use of the recoupled dipole polarizability to separate isotropic and anisotropic components. Molecular polarizabilities are calculated using the "frequency-dependent atom-condensed Kohn–Sham density functional theory approximated to second order," i.e., the ACKS2ω model. With ACKS2ω, the charge-flow contribution can be constructed in two conceptually distinct ways that appear to yield compatible results. The charge-flow contribution is significantly affected by molecular geometry and the presence of polarizable bonds, in line with previous studies. We show that the charge-flow contribution qualitatively reproduces the polarizability anisotropy. The contribution to the anisotropic C6 coefficients is less pronounced but cannot be neglected. The effect of fluctuating charges is only negligible for small molecules with at most one non-hydrogen atom. They become important and sometimes dominant for larger molecules or when highly polarizable bonds are present, such as conjugated, double, or triple bonds. Charge flow contributions cannot be explained in terms of individual atomic properties because they are affected by non-local features such as chemical bonding and geometry. Therefore, polarizable force fields and dispersion models can benefit from the explicit modeling of charge flow. [ABSTRACT FROM AUTHOR]

Clusters are considered to become increasingly significant for elaborating the nanocrystal's formation mechanism. However, capturing the clusters with high chemical potential is challenging because of the lack of effective strategies. In this work, the key role of ligand–solvent interaction has been revealed for the stabilization of clusters in silver telluride synthesis. The Flory interaction coefficient that comprehensively regards the temperature and dispersion, polarity, and hydrogen bonding of the solvent has been used to evaluate the ligand–solvent interaction and thus assist in the design of synthetic systems. Small silver telluride clusters have been successfully captured, and the composition of the smallest cluster is determined as Ag7Te8(SCy)2 (SCy represents the ligand). This work provides new insights into the design of cluster/nanocrystal synthesis systems and paves the way to revealing the mechanism of precursor–cluster–nanocrystal conversion. [ABSTRACT FROM AUTHOR]

In dispersion, nanoparticles can interact with the surrounding dispersion medium, such that an interfacial region with a structure differing from that of the bulk exists. Distinct nanoparticulate surfaces induce specific degrees of interfacial phenomena, and the availability of surface atoms is a crucial prerequisite for interfacial restructuring. Here, we investigate the nanoparticle–water interface of 0.5–10 wt. % aqueous iron oxide nanoparticle dispersions of 6 nm diameter in the presence of 6 vol. % ethanol with x-ray absorption spectroscopy (XAS) and atomic pair distribution function (PDF) analysis. The absence of surface hydroxyl-groups in XAS spectra is in accordance with the double-difference PDF (dd-PDF) analysis, due to a fully covered surface from the capping agent. The previously observed dd-PDF signal is not stemming from a hydration shell, as postulated in Thomä et al. [Nat Commun. 10, 995 (2019)], but from the residual traces of ethanol from nanoparticle purification. With this article, we provide an insight into the arrangement of EtOH solutes in water at low concentration. [ABSTRACT FROM AUTHOR]

Cocatalyst loading is of critical importance in efficient photocatalytic water splitting over perovskite oxynitrides. Perovskite CaTaO2N was synthesized for enhancing photocatalytic hydrogen evolution via decoration of a Pt cocatalyst by impregnation–reduction and photodeposition methods. The Pt-loaded CaTaO2N photocatalyst evolves 6.4 μmol H2 per hour, with an apparent quantum yield as high as 0.67% at a wavelength of 420 nm. Decorating the cocatalyst with uniform dispersion and intimate contact onto the surface of narrow-bandgap perovskite oxynitrides is an efficient method to upgrade photocatalytic hydrogen evolution from water splitting. [ABSTRACT FROM AUTHOR]

Dispersion of single atoms (SAs) in the host is important for optimizing catalytic activity. Herein, we propose a novel strategy to tune oxygen vacancies in CeO2−X directionally anchoring the single atom platinum (PtSA), which is uniformly dispersed on the rGO. The catalyst's performance for the hydrogen evolution reaction (HER) can be enhanced by controlling different densities of CeO2‐X in rGO. The PtSA performs best optimally densified and loaded on homogeneous and moderately densified CeO2‐X/rGO (PtSA−M−CeO2−X/rGO). It exhibited higher activity in HER with an overpotential of 25 mV at 0.5 M H2SO4 and 33 mV at 1 KOH than that of almost reported electrocatalysts. Furthermore, it exhibited stability for 90 hours at −100 mA cm−2 in 1 KOH and −150 mA cm−2 in 0.5 M H2SO4 conditions, respectively. Through comprehensive experiments and theoretical calculations, the suitable dispersion density of PtSA on the defects of CeO2−X with more active sites gives the potential for practical applications. This research paves the way for developing single‐atom catalysts with exceptional catalytic activity and stability, holding promise in advanced green energy conversion through defects engineering. [ABSTRACT FROM AUTHOR]

Seismic wave forward modelling is a crucial method for studying the propagation characteristics of seismic waves in subsurface media and is a key component of full waveform inversion. Compared to time‐domain forward modelling, frequency‐domain forward modelling offers advantages such as not being constrained by stability limits and reducing the dimension of the solution space. However, forward algorithms based on the rotation coordinate system in the frequency domain cannot adapt to situations with unequal spatial sampling intervals. To enhance the adaptability of the forward modelling algorithm in the frequency domain, we derived a 21‐point finite‐difference scheme based on the average derivative method and calculated the difference coefficients and dispersion conditions. Additionally, to address the significant computational cost in frequency domain forward modelling, we developed an improved 25‐point finite‐difference scheme. The improved 25‐point format is more accurate than the conventional 25‐point format. Building on this foundation, we applied the two derived differential schemes to full waveform inversion to synthesize the shot records of the inversion data. Additionally, we introduced a frequency compensation factor into the gradient processing, which effectively compensates for the deep layer while suppressing noise in the shallow gradient field. Finally, we demonstrated the effectiveness of our approach through a full waveform inversion application on the Marmousi model showcasing its capability in invertig fine subsurface structures. [ABSTRACT FROM AUTHOR]

Over the last twenty years, more research has been conducted on the application of nanolime as a consolidant. However, a limitation in consolidation with nanolime is the back-migration of the product to the absorption surface during the drying phase, resulting in insufficient product deposition in depth. In this paper, a solvent composition is adapted to the substrate properties to examine the theory that a nanolime with low kinetic stability should be applied to prevent back-migration to the absorption surface for a substrate with large pore size. The common solvent composition of 100% ethanol has a kinetic stability considered too high. Nanolime dispersions (CaLoSiL® E 20 g/L) with different ethanol:water (100:0, 95:5, 90:10, 80:20) ratios were tested on lime mortar samples. The treated samples were subjected to several test methods to evaluate the effectiveness of the consolidation treatment. After comparing the results, the theoretical propositions were substantiated: a back-migration was noticeable in samples treated with the nanolime containing 100% ethanol, while no back-migration was observed in the other solvent compositions. Samples treated with a nanolime dispersion with the addition of 10% deionised water showed promising results regarding mechanical strength, product deposition over the entire depth profile of the sample, and porosity properties. [ABSTRACT FROM AUTHOR]

In present work, using the double layer ONIOM methodology, we simulated the stages of initiation and growth of the polymer chain during the polymerization of butadiene on a neodymium‐based Ziegler–Natta catalyst. The DFT methods B3LYP and PBE0 in combination with the Def2‐TZVP atomic basis set were used as high‐level methods in ONIOM. Grimme's semi‐empirical XTB1 method was used as a low‐level method. In our previous work, the mechanism of butadiene polymerization on a neodymium‐containing Ziegler–Natta catalyst was studied in detail. The polymerization activation energy of 61 kJ/mol was found to be slightly higher than the experimentally determined values of this parameter. In the present work, the influence of a high‐level method and a model of taking into account dispersion interactions on the quality of calculation of activation parameters of the polymerization reaction was studied. Experimental activation energy for the polymerization of dienes in the presence of Ziegler–Natta catalysts is in the range of 30–60 kJ/mol, but neodymium‐based catalysts have an activation energy somewhat closer to the lower limit of this range. For comparison, semi‐empirical Grimme models D3 and D4 were used. It has been established that the both models reveal within the B3LYP method the activation energy practically the same, while within the PBE0 method it decreases to 41 kJ/mol. Thus, using the PBE0 as a high‐level method within the ONIOM methodology and taking into account dispersion interactions within the D4 model leads to results in much better agreement with experimental data. [ABSTRACT FROM AUTHOR]

In symmetry‐adapted perturbation theory (SAPT), accurate calculations on non‐covalent interaction (NCI) for large complexes with more than 50 atoms are time‐consuming using large basis sets. More efficient ones with smaller basis sets usually result in poor prediction in terms of dispersion and overall energies. In this study, we propose two composite methods with baseline calculated at SAPT2/aug‐cc‐pVDZ and SAPT2/aug‐cc‐pVTZ with dispersion term corrected at SAPT2+ level using bond functions and smaller basis set with δMP2 corrections respectively. Benchmark results on representative NCI data sets, such as S22, S66, and so forth, show significant improvements on the accuracy compared to the original SAPT Silver standard and comparable to SAPT Gold standard in some cases with much less computational cost. [ABSTRACT FROM AUTHOR]

[Display omitted] The formation of soft colloidal crystals, which are nonclose-packed ordered arrays of colloidal particles suspended in a solvent, is dictated by a single physical factor that yields a fixed threshold at order–disorder boundaries for different experimental conditions such as ion concentration, solvent type, and particle size. Identifying the determinant factor and its threshold value should enable the prediction of the critical concentrations of colloidal particles to form soft colloidal crystals. Soft colloidal crystals were fabricated using a series of monohydric alcohols as dispersion media and reflectance spectra were measured to locate order–disorder boundaries. The interaction forces acting between particles were also measured by employing atomic force microscopy. The interparticle forces at the order–disorder boundaries exhibited a universal threshold that was independent of the solvent types including alcohols and water. Therefore, the determinant factor for the formation of soft colloidal crystals was determined to be the force acting between the particles. Furthermore, a priori calculation of this critical force and consequently the critical particle concentration in colloidal systems was demonstrated by referring to the pressure at the liquid-to-solid transition in a hard sphere system (Alder transition). [ABSTRACT FROM AUTHOR]

In this paper, we propose a new complexity computation based on the complex function. This measure exploits the dispersion Lempel–Ziv complexity (DLZC) and the dispersion statistical complexity measure based on Jensen–Shannon divergence (DCJS) of the analytic signal and constructs the binary complex function, called complex number complexity (CNC). The statistical measure depicts the complex system from different angle and mines more potential information. Through simulation experiments, we prove that the proposed method is able to detect data fluctuations more sensitively and accurately. For an application, the CNC is applied to fault detection which has different fault diameters and rotational speeds. The results deliver that the CNC measure can well represent the complexity of faulty bearings and has significant differences in any two fault types. The technique is effective to characterize different fault. [ABSTRACT FROM AUTHOR]

This paper focuses on the existence of normalized solutions for the Chern–Simons–Schrödinger system with mixed dispersion and critical exponential growth. These solutions correspond to critical points of the underlying energy functional under the L2$$ {L}^2 $$‐norm constraint, namely, ∫ℝ2u2dx=c>0$$ {\int}_{{\mathrm{\mathbb{R}}}^2}{u}^2\mathrm{d}x=c>0 $$. Under certain mild assumptions, we establish the existence of nontrivial solutions by developing new mathematical strategies and analytical techniques for the given system. These results extend and improve the results in the existing literature. [ABSTRACT FROM AUTHOR]

A four-level atomic medium driven by probe and control fields is used to control and modify linear and nonlinear absorption and gain. The normal and anomalous dispersions as well as group index are also controlled by the strength and parameters of driving fields. The angular momentum l of the redefined Rabi frequencies of the control fields intensify the number of absorption and gain peaks according to 2 l 2 condition. Normal dispersion is observed in the region of gain while anomalous dispersion is noted in the region of absorption. The negative group index is studied in the anomalous dispersive region and the positive group index is associated with the normal dispersion region. The normal/anomalous dispersive region and positive/negative group index region also increased by the angular momentum l of the control fields according to 2 l 2 formula. A positive group index of 1000 is calculated, which reduces the group velocity to 3 × 10 5 m/s . An approximate negative group index of - 1000 is calculated, demonstrating superluminality of the group velocity at - 1 / 3 × 10 5 m/s . The modified results of the current study are useful for speeding up computer chips and time cloak technology. [ABSTRACT FROM AUTHOR]

We have developed a new type of hybrid-structured Photonic Crystal Fiber (H-PCF) that includes a sectored core-cladding configuration. It's composed of a cladding with a regular circular sectored lattice structure and a core with a hexagonal sectored lattice structure. To extensively design, analyze, and calculate the fiber's properties, the finite element method has been used. The results provide validation for the superior performance of this novel fiber design. It simultaneously achieves extremely low effective material loss and confinement loss equal to 0.0145 cm⁻1 and 1 × 10⁻14 cm⁻1, respectively, at the 1 THz frequency. Furthermore, the fiber demonstrates nearly zero flattened dispersion (− 0.45 ± 0.55 ps/THz/cm) across the 0.9–1.3 THz frequency range, along with important attributes such as a large core power fraction (50%) and an effective area of 5 × 105 µm2. The suggested PCF design is practical for manufacturing utilizing currently available technologies. Moreover, the proposed PCF design, employing common structured regions in the circular and hexagonal patterns for the sectored cladding and core regions, respectively, is feasible for fabrication using existing technologies. Overall, this H-PCF shows significant potential for various THz applications, especially in THz wave guidance. [ABSTRACT FROM AUTHOR]

Document level event extraction faces two major challenges: argument dispersion and multiple events. Most existing work adopts the method of extracting candidate arguments sentence by sentence, which makes it difficult to model contextual information across sentences. Therefore, this paper proposed a document level event extraction model based on multi granularity readers and graph attention networks. It used multi-granularity readers to achieve multi-level semantic encoding, and used the graph attention network to capture local and global relations between entity pairs. It constructed a pruned complete graph based on entity pair similarity as a pseudo trigger to comprehensively capture events and arguments in the document. Experiments conducted on the public datasets of ChFinAnn and DuEE-Fin show that the proposed method improves the problem of argument dispersion and enhances model s event extraction performance. [ABSTRACT FROM AUTHOR]

An editorial focuses on an advanced method for Dix-type multi-component Scholte wave dispersion inversion that does not require an initial model. It introduces improvements to the inversion process by incorporating adaptive step and damping factors, which enhance computational efficiency and accuracy. It addresses issues associated with traditional inversion techniques that rely on initial models and exhibit slower convergence rates.

Non-conventional resonances, both acoustic and photonic, are found in metallic particles with a toroidal nanopropeller geometry, which is generated by sweeping a three-lobed 2D shape along a spiral with twisting angle α. For both optical and acoustic cases, the spectral location of resonances experiences a red-shift as a function of α. We demonstrate that the optical case can be understood as a natural evolution of resonances as the spiral length of the toroidal nanopropeller increases with α , implying a huge helicity-dependent absorption cross-section. In the case of acoustic response, two red-shifting breathing modes are identified. Additionally, even a small α allows the appearance of new low-frequency resonances, whose spectral dispersion depends on a competition between the length of the generative spiral and the pitch of the toroidal nanopropeller. [ABSTRACT FROM AUTHOR]

Dispersion interactions are ubiquitous weak interactions that can play a role in many chemical events. Tailor-made catalysts and additives can lead to more selective reactions by properly exploiting dispersion interactions. Although radical-π dispersion interactions are known to have an important stabilizing role, this concept has been so far overlooked in synthetic photochemistry. We recently proved that similar dispersion interactions can play a profound impact on several reactions involving an energy transfer step. We present herein a study on the co-catalytic effect of tethered bi-naphthyl derivatives on the visible-light-promoted alkene-alkene [2 + 2] cycloaddition. A library of tethered bi-naphthyl derivatives was prepared in order to evaluate the impact of the tether on the efficiency of the prototypical [2 + 2] cycloaddition. The best performing additives showed a dramatic effect on the efficiency of the cyclization, and a rationalization of their relative efficiency was carried out through DFT modeling. The best co-catalyst allowed one to isolate desired products in good to excellent yields even employing several challenging substrates. These results offer new tools to devise optimized [2 + 2] photocycloaddition methods and provide valuable information for the design of organic co-catalyst that can boost photochemical reactions by exploiting dispersion interactions. [ABSTRACT FROM AUTHOR]

The addition of two-dimensional inorganic nanomaterials can effectively enhance the properties of polyethylene (PE). In the present study, a series of high-performance PE/oleic acid (OA)–siloxene nanocomposites were prepared by in situ polymerization using OA–siloxene-supported Ziegler–Natta catalysts. Compared with the conventional Ziegler–Natta catalyst, the polymerization activity of the OA–siloxene-supported Ziegler–Natta catalyst was enhanced to 100 kg/mol-Ti•h, an increase of 56%. The OA–siloxene fillers exhibited excellent dispersion within the PE matrix through the in situ polymerization technique. Compared to pure PE, PE/OA–siloxene nanocomposites containing 1.13 wt% content of OA–siloxene showed 68.3 °C, 126%, 37%, and 46% enhancements in Tdmax, breaking strength, modulus, and elongation at break, respectively. [ABSTRACT FROM AUTHOR]

From the time-dependent Gross equation, we find the quasiparticle dispersion law for a one-dimensional weakly interacting Bose gas with a non-point interatomic potential and zero boundary conditions (BCs). The result coincides with the dispersion law for periodic BCs, i.e., the Bogoliubov law E B (k) = ħ 2 k 2 2 m 2 + n 0 ν (k) ħ 2 k 2 m . In the case of periodic BCs, the dispersion law can be easily derived from Gross' equation. However, for zero BCs, the analysis is not so simple. [ABSTRACT FROM AUTHOR]

It is highly desired that performance of Pd catalysts is improved by the design and preparation of homogeneously dispersed and stablized in many industrial catalytic processes and still a big challenge. Herein, small-sized Pd over Al2O3-flower (f-Al2O3) via compartmentalization strategy is successfully prepared. Ultrafine Pd phases are highly dispersed and thermally stabilized by flower-liked architectures, which not only efficiently suppress Pd aggregation at reaction conditions, but also promote mass transport and reactants access to active sites easily. The catalysts exhibit a stable acetylene conversion of 93% with ethylene selectivity of 94% within a single running of 60 days (60 ℃, GHSV 4500 h−1) without introducing any promoter, and high TOF value (0.4 S−1) are achieved as well. This work provides a facile strategy of improving the activity and thermal stability of Al2O3-supported nano-catalysts in industrial application. [ABSTRACT FROM AUTHOR]

A Molybdate intercalated copper–aluminium hydrotalcite (CAM) material was synthesised using a simple co-precipitation technique, employing varying amounts of molybdate anions. Powder XRD, FT-IR, and TEM studies revealed the presence of molybdate species in the interlayer spaces and the formation of layered hydrotalcite structures. The resultant CAM materials have been explored for the hydrogenation of 5-hydroxymethyl furan using water as a green solvent in liquid-phase conditions under a hydrogen atmosphere. The catalyst showed around 60% conversion with the selective formation of 2,5-bishydroxymethyl furan (BHMF). The activity remains intact for five cycles. The increase in reaction temperature enhanced the conversion level to 80%, with the cost of a decrease in the selectivity of BHMF to 74%. The uniform dispersion of copper-molybdenum and strong interaction in the presence of a hydrogen atmosphere favoured better activity. [ABSTRACT FROM AUTHOR]

In open flow simulations, the dispersion characteristics of disturbances near synthetic boundaries can lead to unphysical boundary scattering interactions that contaminate the resolved flow upstream by propagating numerical artifacts back into the domain interior. This issue is exacerbated in flows influenced by real or apparent body forces, which can significantly disrupt the normal stress balance along outflow boundaries and generate spurious pressure disturbances. To address this problem, this paper develops a zero-parameter, physics-based outflow boundary condition (BC) designed to minimize pressure scattering from body forces and pseudo-forces and enhance transparency of the artificial boundary. This "balanced outflow BC" is then compared against other common BCs from the literature using example axisymmetric and three-dimensional open swirling flow computations. Due to centrifugal and Coriolis forces, swirling flows are known to be particularly challenging to simulate in open geometries, as these apparent forces induce non-trivial hydrostatic stress distributions along artificial boundaries that cause scattering issues. In this context, the balanced outflow BC is shown to correspond to a geostrophic hydrostatic stress correction that balances the induced pressure gradients. Unlike the alternatives, the balanced outflow BC yields accurate results in truncated domains for both linear and nonlinear computations without requiring assumptions about wave characteristics along the boundary. [ABSTRACT FROM AUTHOR]

Anomalous guided waves appearing at a non-semisimple degeneracy of the fundamental matrix are observed and analyzed in the framework of the Cauchy sextic formalism. The non-semisimple degeneracy condition is explicitly constructed for the most general case of Lamb waves propagating in a traction-free layer with arbitrary elastic anisotropy. A new type of dispersion equation and the corresponding dispersion solution are obtained. The connection with surface waves of the non-Rayleigh type is discussed. [ABSTRACT FROM AUTHOR]

Various spatial-gradient extensions of standard viscoelastic rheologies of the Kelvin–Voigt, Maxwell's, and Jeffreys' types are analysed in linear one-dimensional situations as far as the propagation of waves and their dispersion and attenuation. These gradient extensions are then presented in the large-strain nonlinear variants where they are sometimes used rather for purely analytical reasons either in the Lagrangian or the Eulerian formulations without realizing this wave propagation context. The interconnection between these two modelling aspects is thus revealed in particular selected cases. [ABSTRACT FROM AUTHOR]

The profound attempts to promote financial inclusion (FI) need more scrutiny for better policy insights. This paper, therefore, assesses the nature of FI in terms of geographical dispersion, convergence, and implications on development goals using various FI measures for a large cross-section of countries. The findings indicate that FI is multifaceted, accounting for a diverse geographical dispersion across countries in terms of financial access and use. FI, over the years, has progressed significantly while mobile money transition in developing countries shows a gradual progress, focusing on certain regions. We observe FI convergence across countries, albeit at a slower rate. FI can act as a tool for promoting income per capita and human development index, especially in developing countries. Nevertheless, the impact of FI on inequality is limited, requiring policymakers to formulate a better governance system to promote FI as a catalyst. Policy implications are further discussed. [ABSTRACT FROM AUTHOR]

An experiment was carried out using a scale model of a tall building, with the goal of investigating the role of individual buildings in the dispersion of air pollution. Pollutant dispersion around an isolated building with a height-to-length aspect ratio of 1.4 is investigated using simultaneous particle image velocimetry and planar laser induced fluorescence. Dye is released from a ground-level point source five building heights upstream of the tall building. It was found that in this case the scalar plume was dispersed laterally strongly by the building, but only slightly vertically. It is hypothesized that this is due to 94% of the plume impinging below the stagnation point on the front of the building and being drawn into the horseshoe vortex. We expect this fraction would be lower in a case in which the building is in an array of smaller buildings, and that this would lead to more vertical dispersion. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAp) is a bioactive and important material for medical applications. Therefore, search for new possibilities in combining hydroxyapatite with other compounds opens a promising path for creating innovative biomaterials. For this purpose, the preparation of effective aqueous colloidal dispersions based on nanohydroxyapatite (nHAp) of varying degrees of crystallinity and morphology was investigated. Nanohydroxyapatite was prepared by co-precipitation with post-processed freeze-drying, hot-air drying, sintering, and hydrothermal synthesis with tri-sodium citrate. The prepared nanosized powders were analyzed by using X-ray powder diffraction, scanning, and transmission electron microscopy techniques. The influence of post-processing techniques, such as lyophilization, freezing, hot-air drying, and sintering, on the crystallinity and morphology of prepared nanohydroxyapatite suspensions was investigated. Aqueous nanohydroxyapatite colloidal dispersions were prepared using deionized water and tri-sodium citrate solution (0.01 % wt.) with an ultrasonic homogenizer. The study demonstrated that the most effective aqueous colloidal dispersion of nHAp (stable for at least 14 days) can only be obtained using a tri-sodium citrate solution together with freeze-drying. When the material shows higher crystallinity and a more clearly rod-like shape, even tri-sodium citrate does not help maintain the stability of the colloids for a long time. These findings are significant for future investigation involving the preparation of new materials based on nHAp, such as hydrogels, membranes, scaffolds, cement, and composites for biomedical applications. They can be applied in theranostics and drug delivery systems. [Display omitted] • An effect of synthesis and post-processing method related to the hydroxyapatite (nHAp) was shown. • The post-treatment of nHAp is critical for its colloidal dispersions. • The use of freeze-drying and tri-sodium citrate allows the colloids to remain stable for at least 14 days. [ABSTRACT FROM AUTHOR]

In this study, a promising monolithic catalyst composition for the production of syngas using bi-reforming (BRM) of CH4–CO2 mixture was proposed. The BRM performance was evaluated with N2/CH4/H2O/CO2 (1/1/0.8/0.4) mixture at 700–800 °C. First, the influence of MgO loading on the activity of 10 wt.% of Ni supported on xMgAl (x is MgO content, x = 10–40 wt.%) powder catalyst was studied. The addition of 10–20 wt.% of MgO leads to higher reforming performance, probably due to the formation of MgAl2O4 phase that enhance the Ni dispersion. At 800 °C, the CH4 conversion and H2 yield obtained with Ni/20MgAl are 1.7 and 1.5 times, respectively, higher than that of the Ni/Al catalyst. However, higher MgO loading causes a coverage of Ni active sites and decrease activity. Ni/20MgAl powder catalyst exhibit highest activity and this sample was then deposited on monolith substrate. The monolith catalyst shows higher BRM activity than powder form. Long-term test demonstrates high stability of monolith catalyst with less than 5% the losses in CH4 and CO2 conversions after 60 h time on stream. CH4 and CO2 conversion are 89% and 81%, respectively. The H2/CO ratio is near 2, which meets the requirement for methanol/Fischer–Tropsch fuel synthesis. [ABSTRACT FROM AUTHOR]