bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustoelectric properties of bismuth in the presence of a nonuniform current distribution
Authors: Bengus S. V. , Krasovitskiĭ Vit. B. , Finkel’ P. E.
Published: February 2025

Acoustoelectric nonlinearity is created in pure perfect bismuth single crystals with a nonuniformly distributed electric field (which is defined by means of current contacts on a side face of the sample). It is shown that the longitudinal conductivity becomes nonuniform in the nonlinear electric field interval. A technique is proposed for the excitation of acoustoelectric oscillations for any combination of current, magnetic field, and temperature. It is clearly demonstrated that oscillations are excited whenever the phonon-electron mechanism of relaxation of nonequilibrium phonons is activated.
Influence of random static deformations on the impurity specific heat of dilute solutions of 14N2 in solid Kr
Authors: Bagatskiĭ M. G. , Manzheliĭ V. G. , Muromtsev P. I. , Minchina I. Ya.
Published: February 2025

The molar specific heats of binary solid solutions Kr–n14N2 (n = 0.25, 0.7, 1 mol. %) and ternary solid solutions Kr–0.25%14N2 – x Ar (x = 2, 9, 24.4 mol. %) are measured in the temperature interval from 0.5 K to 6–9 K. It is established that the values and temperature dependence of the specific heat ΔC associated with rotational motion of the matrix-isolated 14N2 molecules depend strongly on the static deformations created by Ar atoms in the Kr lattice. Evidence of glasslike behavior of the specific heat ΔC is observed in the ternary solutions.
Elastic and magnetic properties of La2CuO4–δ single crystals
Authors: Burma N. G. , Gaǐduk A. L. , Zherlitsyn S. V. , Kolobov I. G. , Fil’ V. D. , Panfilov A. S. , Svechkarev I. V. , Ges’ A. P. , Barilo S. N. , Zhigunov D. I.
Published: February 2025

Measurements of the absolute sound velocities in a La2CuO4 single crystal are the basis for the assumption that monoclinic distortions exist in the La2CuO4 lattice. The twin-structure-averaged components of the elastic modulus tensor are determined. The moduli c˜11 and c˜11−c˜12/2 are observed to undergo anomalous softening that is correlated with the behavior of the magnetic susceptibility.
On the theory of a Bose gas in a nonuniform field
Authors: Shevchenko S. I.
Published: February 2025

A new method of description of Bose systems in external fields is proposed. Equations derived on the basis of this method are the Bose analog of the Bogolyubov–De Gennes equations for Fermi systems with pairing. An exact solution of the equations is obtained for the case when a Bose system is in a field varying linearly with the coordinate. The possibility of propagation of previously unknown surface oscillations in a nonuniform field is predicted. The effect of the nonuniform field on the long-range order in two- and three-dimensional Bose systems is investigated.
Critical currents in ceramic HTS superconductors
Authors: Ventsel’ V. A. , Ivanov L. A. , Petrova A. E. , Rudnev A. V. , Khlybov E. P.
Published: February 2025

The method of magnetic field measurement at the center of a hollow cylinder in both increasing and decreasing magnetic fields is used to evaluate the critical current density jc for Bi-, Y-, Nd-, and Er-based HTS ceramics pressed under high pressures and at high temperatures. It is shown that the intergranular current density in the samples is negligibly low while it attains values jc(0)∼ 105 A/cm2 in grains under zero field at T = 4.2 K, and depends on magnetic fields up to 90 kOe as jc(H) =jc(0) exp (– H/H*) or jc(H) =jc(0)[1+H/H*] −1
Oscillation and galvanomagnetic characteristics under a strong axial compression and impurity levels in bismuth–antimony superconducting alloys
Authors: Bogdanov E. V. , Butko N. B. , Kirakozova L. A. , Minina N. Ya. , Savin A. M.
Published: February 2025

The Fermi surface, the Dingle temperature, and galvanomagnetic characteristics are investigated in semiconducting alloys Bi1–xSbx (0.009 ≤ x ≤ 0.16) under a strong axial compression along the binary and bisector axes. An axial strain up to 0.3% makes it possible for the Fermi level to pass through the forbidden band at certain energy extrema. The experimental data obtained do not indicate the presence of a deep donor level with a high density of states in the forbidden band of the alloys under investigation, which was predicted in some publications. It is shown that a specific microscopic inhomogeneity of the “cluster type” of about 10–20 μm in size, which was detected in bismuth-antimony alloys, is not manifested in oscillatory effects, although it is responsible for an anomalous behavior of resistance in the range of strains corresponding to the passage of the Fermi level through the forbidden band.
Increase in the critical temperature of a two-band superconductor in a topological transition
Authors: Poluéktov Yu. M. , Zhukov A. I.
Published: February 2025

A change in the critical temperature Tc as a result of a topological transition is investigated by using the two-band model of superconductivity. It is shown that the emergence of electrons in an empty band or holes in a completely filled band is accompanied by an increase in the critical temperature. The realistic choice of the parameters of the model makes it possible to describe the nonlinear increase in the critical temperature observed in experiments in which the effect of impurities on Tc is investigated.
Probing specific ion effects at air-aqueous dibutyl phosphate interfaces using vibrational sum frequency generation spectroscopy
Authors: Louie Christina , Adhikari Narendra , Boamah Mavis D. , Clark Sue , Tuladhar Aashish , Pearce Carolyn I. , Rosso Kevin M. , Wang Zheming
Published: February 2025

Molecular properties at air–liquid and liquid–liquid interface hold the key to many processes involving molecular transport across phase boundaries from aerosol formation to carbon cycling and material separation using solvent extraction techniques. Using dibutyl phosphate (DBP) as a representative for partially aqueous soluble surfactants, the specific ion effect (SIE) of the Hofmeister series cations Cs+, Na+, Li+, and Mg2+ on the partition and interaction between surfactant molecules and water molecules in the air–aqueous interface are investigated using vibrational sum frequency generation spectroscopy and surface tension measurements. In the presence of 1 mM and 1M bulk aqueous phase ionic strength salt concentrations, fundamental qualitative relationships are observed for the salting out of DBP relative to bulk aqueous phase nitrate salt concentrations and the specific cations species. At 1 mM ionic strength, the interfacial charge and hence the interfacial potential modulates the electrostatic interactions; in particular, the counter cations partially screen the negatively charged interface induced by the DBP in a direct Hofmeister order. At 1M ionic strength, the electric field at the interface or interfacial potential is effectively neutralized, and the counter cations promote the partitioning of DBP to the interface depending on their specific interaction with the DBP head group and metal ion hydration properties. The present results lay a foundation to study SIEs of heavier metals on hydrophobic-aqueous DBP interfaces.
Inferring interphase chromosomal structure from multiplexed fluorescence in situ hybridization data: A unified picture from human and mouse cells
Authors: Remini Loucif , Segers Midas , Parmeggiani Andrea , Carlon Enrico
Published: February 2025

We analyze multiplexed fluorescence in situ hybridization (m-FISH) data for human and mouse cell lines. The m-FISH technique uses fluorescently-labeled single-stranded probes which hybridize to specific chromosomal regions, thereby allowing the measurement of the spatial positions of up to ∼100 tagged sites for several thousands of interphase chromosomes. Our analysis focuses on a wide range of different cell lines and two distinct organisms and provides a unified picture of chromatin structure for scales ranging from 5 kb (kilobases) up to 2 Mb (megabases), thus covering a genomic region of almost three orders of magnitude. Confirming recent analysis [Remini et al., Phys. Rev. E 109, 024408 (2024)], we show that there are two characteristic arrangements of chromatin referred to as phase α (crumpled globule) and phase β (looped domain) and discuss the physical properties of these phases. We show that a simple heterogeneous random walk model captures the main behavior observed in experiments and brings considerable insights into chromosomal structure.
ML-MCTDH-Aid: An auxiliary package for multilayer multiconfiguration time-dependent Hartree calculations
Authors: Zheng Jie , Xie Yu , Peng Jiawei , Han Zhaohui , Lan Zhenggang
Published: February 2025

The multilayer-multiconfiguration time-dependent Hartree (ML-MCTDH) method has garnered significant attention in the realm of theoretical chemistry owing to its powerful ability to perform numerically exact descriptions of multi-dimensional quantum dynamics and exhibit the remarkable performance in simulating the nonadiabatic dynamics of complex systems. Despite the availability of computational packages within the ML-MCTDH framework, executing these calculations seamlessly is not a straightforward task. Typically, substantial efforts are necessitated to configure the correct inputs for ML-MCTDH calculations, which require to correctly define several non-trivial parameters, to reasonably setup the optimal tree expansion of wavefunctions, and to properly select basis function numbers. To address these challenges, we have developed an auxiliary package named ML-MCTDH-Aid, which facilitates the setup of ML-MCTDH calculations using the Heidelberg MCTDH package in a user-friendly manner. This package is primarily tailored to handle the high-dimensional nonadiabatic dynamics governed by the Hamiltonian composed of several electronic states, several vibrational modes and their linear vibronic coupling terms. It automatically generates multiple essential input files, and all the calculations can be performed in an all-in-one black-box easy-to-use manner. To show the utility of the ML-MCTDH-Aid package, we provide a step-by-step tutorial that demonstrates running ML-MCTDH studies on three models. These examples illuminate how the utilization of the ML-MCTDH-Aid package significantly enhances the efficiency and effectiveness of ML-MCTDH calculations. This substantially boosts the accessibility of ML-MCTDH calculations in tackling the high-dimensional quantum dynamics of complex systems.
Design of a high-efficiency S-band relativistic klystron oscillator under a low guiding magnetic field
Authors: Li Jiawen , Deng Rujin , Ge Xingjun , Dang Fangchao , Zhang Peng , Yang Fuxiang , Zhang Kejia , Chi Hang
Published: February 2025

A high-efficiency S-band relativistic klystron oscillator (RKO) under a low guiding magnetic field is proposed and investigated in detail in this paper. Two-stage segmented modulation is introduced to compensate for the poor coherence of the electron beam, allowing the electron beam to be deeply modulated even under a low guiding magnetic field. In the particle-in-cell simulation, the proposed RKO generates a microwave with an output power of 3.66 GW at 3.10 GHz under a guiding magnetic field of 0.7 T, corresponding to the power conversion efficiency of 41.3%. To substantiate the practical performance, an experimental validation of the proposed RKO is conducted. The RKO successfully generates a microwave with an output power of 3.02 GW at 3.08 GHz, achieving a power conversion efficiency of 32.2%, under a guiding magnetic field of 0.71 T. These findings confirm that the S-band high-power microwave source can work with high power conversion efficiency under a low guiding magnetic field.
Collective dynamic length increases monotonically in pinned and unpinned glass forming systems
Authors: Das Rajsekhar , Kirkpatrick T. R. , Thirumalai D.
Published: February 2025

The Random First-Order Transition (RFOT) theory predicts that transport proceeds by the cooperative movement of particles in domains, whose sizes increase as a liquid is compressed above a characteristic volume fraction, ϕd. The rounded dynamical transition around ϕd, which signals a crossover to activated transport, is accompanied by a growing correlation length that is predicted to diverge at the thermodynamic glass transition density (>ϕd). Simulations and imaging experiments probed the single particle dynamics of mobile particles in response to pinning all the particles in a semi-infinite space or randomly pinning (RP) a fraction of particles in a liquid at equilibrium. The extracted dynamic length increases non-monotonically with a peak around ϕd, which not only depends on the pinning method but is also different from ϕd of the actual liquid. This finding is at variance with the results obtained using the small wavelength limit of a four-point structure factor for unpinned systems. To obtain a consistent picture of the growth of the dynamic length, one that is impervious to the use of RP, we introduce a multiparticle structure factor, Smpc(q,t), that probes collective dynamics. The collective dynamical length, calculated from the small wave vector limit of Smpc(q,t), increases monotonically as a function of the volume fraction in a glass-forming binary mixture of charged colloidal particles in both unpinned and pinned systems. This prediction, which also holds in the presence of added monovalent salt, may be validated using imaging experiments.
Influence of surface chemistry on Li nucleation energetics on graphene-based surfaces
Authors: Li Sichi , Wang Bo , Heo Tae Wook , Wood Marissa
Published: February 2025

Lithium metal is a promising high-capacity anode material for solid-state batteries, but it typically suffers from poor cyclability. Carbon scaffold hosts have the potential to improve this performance due to their high electronic conductivity and large surface area, which facilitates lithium-ion adsorption and desorption. Scaffold surface chemistry is known to significantly influence performance outcomes, but the details of these interactions are not fully understood. This study employs first-principles simulations to explore lithium transport and nucleation on graphene anodes with various surface chemistries. Using enhanced sampling techniques, ab initio molecular dynamics, and density functional theory calculations, we find that although surface chemistry has a minimal impact on lithium interfacial transport, it influences surface nucleation significantly. Both heteroatom dopants and intrinsic defects lower the nucleation barrier, creating a more favorable environment for lithium nucleation compared to pristine graphene. In addition, our results reveal a complex interplay between surface lithium concentration, lithium transport, and nucleation kinetics. These findings highlight the potential of surface modifications to precisely control nucleation processes on carbon-based anodes and provide design guidance for reducing dendrite formation and improving the cycle life of solid-state batteries.
Theoretical design of nanocatalysts based on (Fe2O3)n clusters for hydrogen production from ammonia
Authors: Ibragimov Sapajan , Lyalin Andrey , Kumar Sonu , Ono Yuriko , Taketsugu Tetsuya , Bobrowski Maciej
Published: February 2025

The catalytic activities of high-spin small Fe(III) oxides have been investigated for efficient hydrogen production through ammonia decomposition, using the artificial force induced reaction method within the framework of density functional theory with the B3LYP hybrid exchange–correlation functional. Our results reveal that the adsorption free energy of NH3 on (Fe2O3)n (n = 1–4) decreases with increasing cluster size up to n = 3, followed by a slight increase at n = 4. The strongest NH3 adsorption energy, 28.55 kcal/mol, was found for Fe2O3, where NH3 interacts with a two-coordinated Fe site, forming an Fe–N bond with a length of 2.11 Å. A comparative analysis of NH3 dehydrogenation and H2 formation on various Fe(III) oxide sizes identifies the rate-determining steps for each reaction. We found that the rate-determining step for the full NH3 dehydrogenation on (Fe2O3)n (n = 1–4) is size-dependent, with the NH* → N* + H* reaction acting as the limiting step for n = 1–3. In addition, our findings indicate that H2 formation is favored following the partial decomposition of NH3 on Fe(III) oxides.
Optimal control design strategies for pulsed dynamic nuclear polarization
Authors: Carvalho José P. , Goodwin David L. , Wili Nino , Nielsen Anders Bodholt , Nielsen Niels Chr.
Published: February 2025

We present optimal control methods for the optimization of periodic pulsed dynamic nuclear polarization (DNP) sequences. Specifically, we address the challenge of the optimization of a basic and repeated pulse sequence element which, apart from being easily adaptable to spin systems with different coupling interaction sizes, also proves beneficial in terms of performance. It is demonstrated that matrix power and matrix logarithm functions combined with an auxiliary matrix formalism can be used to derive expressions for gradient ascent pulse engineering (GRAPE) optimization. We illustrate how different implementations provide effective and intuitive control of DNP experiments by tailoring the effective Hamiltonian governing polarization transfer and, in this manner, addressing some of the limitations of prevailing optimal control based pulse design strategies.
In situ deformation behavior of laser additive manufacturing Ti–6Al–4V alloy at room and high temperatures: A review
Authors: Abbas Mujahid , Hussain Wajid , Majeed Afraz Hussain , Jalili Bahram , Vivas-Cortez Miguel , Kallel Imen Ali
Published: February 2025

The use of laser directed melting deposited (LDMD) Ti–6Al–4V alloys is mostly seen in the field of aeronautics. Clearly demonstrating the deformation method as a function of application conditions is of utmost importance. The objective of this study was to investigate the mechanical characteristics and dynamic substructure formation of LDMD (Ti–6Al–4V) alloys at different temperatures, namely 23, 650, and 200 °C. This review study examines the mechanisms of deformation at both low and high temperatures. Tensile testing was conducted in situ using scanning electron microscopy to examine the onset and progression of fractures. At temperatures of 23 and 650 °C, the experimental findings demonstrated a strength decrease and elongation increase at the climbed temperature. At a temperature of 200 °C, the microstructure of the sample was composed of inclined α-plates oriented in the direction of construction and columnar β-grains with zigzag grain borders, according to the results. Consequently, when the temperature was increased to 200 °C, a greater degree of elongation and a decrease in cross-sectional area were observed compared to the conditions at ambient temperature.
Dispersion with fixed diagonal matrices: Exchange energy correction and an assessment of the Becke–Roussel exchange hole
Authors: Weckman Timo
Published: February 2025

An exchange-correction to the fixed diagonal matrices (FDM) method is introduced to improve accuracy when employing a single reference wavefunction. In addition, the performance of the Becke–Roussel exchange-hole in approximating the pair density-mediated integrals was explored. With the exchange-correction, the FDM procedure yields dispersion coefficients for closed-shell atoms on par with highly correlated methods when using only Hartree–Fock or Kohn–Sham pair density. Conversely, the Becke–Roussel exchange-hole results in an overestimation of the dispersion coefficients for closed-shell atoms; however, the performance of the Becke–Roussel model can be improved by scaling the multipole moment integrals by a fixed amount. For both the exchange–correction and the Becke–Roussel model, the FDM method continues to fail for open-shell atoms and ions by consistently underestimating the dispersion coefficients.
Topological insights from state manipulation in a classical elastic system
Authors: Mahmood Kazi T. , Hasan M. Arif
Published: February 2025

The exploration of the Berry phase in classical mechanics has opened new frontiers in understanding the dynamics of physical systems, analogous to quantum mechanics. Here, we show controlled accumulation of the Berry phase in a two-level elastic bit, which is a classical counterpart to qubits, achieved by manipulating coupled granules with external drivers. Employing the Bloch sphere representation, the paper demonstrates the manipulation of elastic bit states and the realization of quantum-analog logic gates. A key achievement is the calculation of the Berry phase for various system states, revealing insights into the system’s topological nature. Unique to this study is the use of external parameters to explore topological transitions, contrasting with traditional approaches focusing on internal system modifications. By linking the classical and quantum worlds through the Berry phase of an elastic bit, this work extends the potential applications of topological concepts in designing new materials and computational models.
Electronic-vibrational resonance damping time-dependent photosynthetic energy transfer acceleration revealed by 2D electronic spectroscopy
Authors: Lei Peng , Cheng Jiong , Zhang Chengjie , Zhang Wenzhao , He Hongxing , Leng Xuan
Published: February 2025

The effects of damping time of electronic-vibrational resonance modes on energy transfer in photosynthetic light-harvesting systems are examined. Using the hierarchical equations of motion (HEOM) method, we simulate the linear absorption and two-dimensional electronic spectra (2DES) for a dimer model based on bottleneck sites in the light-harvesting complex of photosystem II. A site-dependent spectral density is incorporated, with only the low-energy site being coupled to the resonance mode. Similar patterns are observed in linear absorption spectra and early time 2DES for various damping times, owing to the weak coupling strength. However, notable differences emerge in the dynamics of the high-energy diagonal and cross-peaks in the 2DES. It is found that the coupling of electronic-vibrational resonance modes accelerates the energy transfer process, with rates being increased as the damping time is extended, but the impact becomes negligible when the damping time exceeds a certain threshold. To evaluate the reliability of the perturbation method, the modified Redfield (MR) method is employed to simulate 2DES under the same conditions. The results from the MR method are aligned with those obtained from the HEOM method, but the MR method predicts faster dynamics.
Excited state dynamics of a Bodipy derivative with a twisted molecular structure: Combined experimental and theoretical studies
Authors: Li Bei , Liao Sheng , Li Jiayu , Chen Xi , Zhang Xue , Zhao Jianzhang , Li Ming-De , Dick Bernhard , Mazzone Gloria , Gurzadyan Gagik G.
Published: February 2025

The photophysical properties of a boron dipyrromethene (Bodipy, BDP) derivative (BDP-SA) in which one F atom at the BDP core was replaced by an O atom and condensed with salicylaldehyde were investigated. This compound has a twisted molecular structure and unusually low fluorescence quantum yield (1% in toluene). No intersystem crossing was observed with a nanosecond transient absorption study. The triplet state lifetime of BDP-SA was determined to be 115 μs by photosensitizing. Femtosecond transient absorption shows a structure relaxation of ∼1.5 ps for the S1 excited state. Theoretical studies show conical intersections, which are responsible for the efficient non-radiative decay of the S1 state, which has extremely weak fluorescence.
Characteristics of contact force for normal collision of rubber sphere with rigid plate
Authors: Wang Yaoyao , Luo Zhuhui , Wang Han , Zhou Xisheng , Wang Hu , Chen Shilu
Published: February 2025

This paper examines the contact force dynamics during a normal collision involving a rubber sphere and a rigid plate. A high-speed camera test system is utilized to capture the key parameters of the sphere. Through image processing, these parameters are extracted. To complement the experimental data, an equivalent finite element model is constructed by using LS-DYNA. The visco-hyperelastic constitutive model parameters are determined by validating against the coefficient of restitution. By comparing the results of the finite element simulation with the experimental outcomes, the model’s accuracy is established. Through simulations, the relationships between the contact force and pertinent variables are explored, deriving an analytical expression for the contact force, which is subsequently verified. Our findings demonstrate that the proposed contact force formulation offers a more precise calculation of the contact force in a normal collision between a rubber sphere and a rigid plate.
Tailoring the interaction between metal atoms and two-dimensional materials through surface functionalization
Authors: Zhang Yongqi , Wang Yusheng , Song Nahong , Liu Qinglin , Wang Sen , Xu Bin , Wang Fei
Published: February 2025

In this study, we employed density functional theory (DFT) to assess the potential of H, F, and O decoration on two-dimensional (2D) materials for modulating the interaction between metal atoms and the 2D substrates. The 2D substrate materials investigated include graphene, black phosphorus, MoS2, and InSe, while the metal atoms considered are Li, Ca, Ti, and Au. The results show that the adsorption energy of 2D materials with metals increases significantly after being functionalized with H, F and O. Furthermore, we observed an enhanced rate of charge transfer and the ability to adjust the diffusion barrier. The decoration with H, F, and O facilitates the stable anchoring of metal atoms on the substrates. This study proposes a practical approach to solving the problem of metal atoms clustering on the surface of 2D materials in the fields of single atom catalysis and hydrogen storage, where the dispersion of metal atoms on the substrate surface is essential.
Toward an FPGA-based dedicated computer for molecular dynamics simulations
Authors: Hamm Peter
Published: February 2025

First steps toward a molecular dynamics (MD) implementation in a cluster of field-programmable gate arrays (FPGAs) are presented, reaching a simulation speed of a few microseconds/day. The nodes in this cluster are programmed into a mid-ranged FPGA (Artix 7 XC7A200T), interconnected as a 3D torus by fast optical links. The implemented MD algorithm is highly parallelized and highly pipelined internally. The FPGA cluster is freely scalable in terms of size, i.e., a larger MD system requires more nodes, however, without compromising simulation speed. The performance in terms of energy stability and simulation speed is analyzed. At present, the focus lies on the fast networking, while only minimal MD functionality has been implemented so far, i.e., Lennard-Jones interactions and a thermostat, which were needed to demonstrate the feasibility of the FPGA cluster to run multi-microsecond simulations. To that end, the nucleation of a super-cooled Lennard-Jones liquid is investigated by unbiased MD simulations, which is a difficult MD problem since a high nucleation barrier has to be overcome. Finally, the pathways toward a full MD implementation are outlined. The current implementation will be made available as an open-source development project.
Study of the electronic structure of NixTiSe2 by EMF method
Authors: Kuznetsova A. Yu. , Suslov E. A. , Shkvarin A. S.
Published: February 2025

The electron structure of the NixTiSe2 system has been studied by the electromotive force (EMF) method in Cu|Cu+|NixTiSe2 and Na|Na+|NixTiSe2 electrochemical cells. Two critical transitions have been found in this system at x = 0.25 and x = 0.35. At these compositions, a change in the nature of the chemical bond of nickel with its local environment occurs. The simple and useful EMF method has been applied as the instrument to study features of electron structure. A comparative analysis of critical points in the electronic structure of the MexTiSe2 (Me = Fe, Co, Ni) intercalate compounds was carried out.
Investigation of new techniques for energy and its applications
Authors: Almuneef Areej , alqahtani Zuhur , El-Shewy E. K. , Abdelrahman Mahmoud A. E.
Published: February 2025

In this article, we present a unified mathematical solver that is widely used in applied nonlinear differential equations based on the well-known tanh–coth method. We employ this solver to provide new solutions for the unstable and modified unstable nonlinear Schrödinger models. We also introduce He’s frequency technique to examine the dynamical behavior properties. The presented solutions include various mathematical structures, such as solitons, dissipative super-waves, bright and dark envelope waves, and explosive envelope waves. The behavior of the presented solutions for suitable free parameter values is depicted by two-dimensional and three-dimensional graphs. The proposed approach offers various benefits, such as eliminating time-consuming and difficult calculations. The results presented here can be utilized to characterize a wide range of physical phenomena in numerous disciplines of practical study, such as pulse propagation in optical fibers and quantum field. Finally, this study increases the current understanding of mathematical methods for solving nonlinear differential equations, which may be applied to other nonlinear wave equations in other scientific areas.
Assessing the influence of far UV-C (222 nm) and UV-C (254 nm) treatment on the physicochemical and microbial properties of milk in an annular flow reactor
Authors: Gadodia Vigyan , Ahlawat Kiran , Ish Ambar , Jangra Ramavtar , Jain Neha , Prakash Ram
Published: February 2025

The quest for alternatives to traditional cold chain preservation and heat-based shelf-life extension has become increasingly important in recent years. As a result, investigation into the effects of ultraviolet (UV) radiation on the physicochemical properties of various substances, including milk, has gained significant attention. UV-C light, in particular, is recognized for its effectiveness in inactivating a wide range of bacteria and spores in aqueous solutions. This work aims to design a continuous annular UV reactor for milk treatment to examine the impacts on milk’s microbial and physicochemical characteristics and compare these outcomes to those achieved through conventional pasteurization methods. For the same, a 11 W conventional UV-C lamp (254 nm) and an in house designed 17.5 W far UV-C (222 nm) lamp have been used. The key parameters, such as pH, conductivity, temperature, fat/solid not fat, and microbial load, are assessed. The UV dosage supplied to milk samples is determined using actinometry and measured to be 6.16 J/ml. The methylene blue reduction test of milk increases up to more than 5 h, with just four passes through the UV reactor. Approximately 5 log reductions in the Salmonella typhimurium and Staphylococcus aureus have been achieved in just three passes (residence time 24.3 s) of whole milk. The results obtained are compared to those obtained using the pasteurization technique. We found that the proposed UV reactor has an identical performance in inactivating the micro-organisms compared to pasteurization without altering the physico-chemical properties. This suggests the possibility of utilizing UV sources to improve milk’s safety, quality, and shelf life. This study expands the scope of applications for UV-C irradiation as a feasible non-thermal method in the dairy industry.
Effect of elevated temperature on wear performance of laser powder bed fusion fabricated SS316L
Authors: Kumar Navin , Chandrakumar Palanisamy , Čep Robert , Arun Prasad M. , Sadilek Marek , Samal S. P.
Published: February 2025

In the field of additive manufacturing, Laser Powder Bed Fusion (LPBF) has become a good technique for manufacturing metallic parts. The aim of this investigation was to clarify how temperature, sliding speed, and load affected the tribological properties of SS316L that was made by LPBF. Test temperature, sliding velocity, and applied load all had a significant impact on sample wear rate as well as their Coefficient of Friction (COF), according to the data. Particular note: at a test temperature of 250 °C, wear rate and COF showed lower values compared to ambient temperature data. The oxide layer formed on the surface that served as a lubricant and reduced material deterioration. Moreover, increased normal loads and decreased sliding velocities were associated with an increasing trend in both COF and wear rate.
Influence of counterion substitution on the properties of imidazolium-based ionic liquid clusters
Authors: Baxter Eric T. , Cao Wenjin , Zhang Difan , Shiery Richard , Nguyen Manh-Thuong , Prabhakaran Venkateshkumar , Wang Xue-Bin , Johnson Grant E.
Published: February 2025

Due to their unique physiochemical properties that may be tailored for specific purposes, ionic liquids (ILs) have been investigated for various applications, including chemical separations, catalysis, energy storage, and space propulsion. The different cations and anions comprising ILs may be selected to optimize a range of desired properties, such as thermal stability, ionic conductivity, and volatility, leading to the designation of certain ILs as designer “green” solvents. The effect of counterions on the properties of ILs is of both fundamental scientific interest and technological importance. Herein, we report a systematic experimental and theoretical investigation of the size, charge, stability toward dissociation, and geometric/electronic structure of 1-ethyl-3-methyl imidazolium (EMIM)-based IL clusters containing two different atomic counterions (i.e., bromide [Br−] and iodide [I−]). This work extends our studies of EMIM+ cations with atomic chloride (Cl−) and molecular tetrafluoroborate (BF4−) anions reported previously by Baxter et al. [Chem. Mater. 34, 2612 (2022)] and Zhang et al. [J. Phys. Chem. Lett. 11, 6844 (2020)], respectively. Distributions of anionic IL clusters were generated in the gas phase using electrospray ionization and characterized by high mass resolution mass spectrometry, energy-resolved collision-induced dissociation, and negative ion photoelectron spectroscopy experiments. The experimental results reveal anion-dependent trends in the size distribution, relative abundance, ionic charge state, stability toward dissociation, and electron binding energies of the IL clusters. Complementary global optimization theory provides molecular-level insights into the bonding and electronic structure of a selected subset of clusters, including their low energy structures and electrostatic potential maps, and how these fundamental characteristics are influenced by anion substitution. Collectively, our findings demonstrate how the fundamental properties of ILs, which determine their suitability for many applications, may be tuned by substituting counterions. These observations are critical in the sub-nanometer cluster size regime where phenomena do not scale predictably to the bulk phase, and each atom counts toward determining behavior.
Applications of multi-GPU computing in large-scale fully kinetic particle-in-cell simulations of space plasma
Authors: Xiong Q. Y. , Huang S. Y. , Yuan Z. G. , Kuang L. L. , Sharma B. , Jiang K. , Wu H. H. , Yu L.
Published: February 2025

The rapid development of an emerging computing device, the graphical processing unit (GPU), has significantly enhanced our ability to conduct full kinetic particle-in-cell (PIC) simulations in space physics. In this paper, we propose an approach that leverages multiple GPUs to facilitate large-scale PIC simulations. This method can effectively reduce data transmission frequency and latency during the computing process. The data communication between GPU devices is optimized through a combination of Message Passing Interface (MPI)-NVIDIA Collective Communications Library (NCCL) running pattern. Our implementation surpasses the expected linear acceleration, achieving superior computing performance and operational efficiency. The instances of large-scale PIC simulations are presented based on physical models of magnetic reconnection, plasma turbulence, and quasi-perpendicular shock. The importance of large-scale simulations is demonstrated in terms of grid resolution, macroparticles used per cell, and the mass ratio between ions and electrons. The multi-GPU enabled fully kinetic PIC simulation demonstrates its capability to efficiently handle large-scale PIC simulations as a crucial requirement for the study of space plasma physics.
The microparticles adhesion and removal dynamics in wafer-scale physical cleaning process
Authors: Zhang Lei , Chai Xinyu , Sun Yadong , Chen Xinglong , Zheng Yunlong
Published: February 2025

The wafer-scale physical cleaning process plays a significant role in the semiconductor industry. In this study, the microparticle adhesion and removal dynamics in the wafer-scale physical cleaning are systematically explored. A lattice Boltzmann method is employed to construct a computational model simulating particle distributions and behaviors in the cleaning process, and the model accuracy is validated with experiments. The effects of nozzle moving velocity, spray droplet velocity, and jetting droplet diameter on microparticle removal efficiency are numerically explored and analyzed. The research shows that, when the nozzle moving velocity reaches a certain value, the cleaning efficiency will no longer increase with the increase in velocity. Moreover, the cleaning efficiency is significantly improved with the increase in spray droplet velocity. It is noted that there are optimized droplet diameters to achieve the superior removal efficiency of 92.9% in physical cleaning process. The research reveals the microparticle adhesion and removal dynamics in the wafer-scale physical cleaning process and offers theoretical guidance for improving the microparticle removal efficiency.
Magneto-electro-thermoelastic interaction in unbounded media containing cylindrical cavities caused by a pulsed heat flux
Authors: Alqahtani Zuhur , Abbas Ibrahim , El-Bary Alaa A. , Almuneef Areej
Published: February 2025

This work applies the generalized magneto-electro-thermoelasticity model to investigate an isotropic thermoelastic medium with an infinite medium containing a cylindrical cavity, which is exposed to a uniform magnetic field along the axis. The cavity boundary is exposed to exponentially decaying pulse boundary heat flux. The solution is derived using an eigenvalues approach based on the Laplace transform technique applied to obtain solutions in the Laplace domain. Numerical inversions, performed through Fourier series expansions, enable the computation of displacement, temperature, radial and hoop stress, and induced electric and magnetic fields. Graphical representations illustrate these results.
Observed declines in upper ocean phosphate-to-nitrate availability
Authors: Gerace Skylar D. , Yu Jun , Moore J. Keith , Martiny Adam C.
Published: February 2025

Climate warming is increasing ocean stratification, which in turn should decrease the nutrient flux to the upper ocean. This may slow marine primary productivity, causing cascading effects throughout food webs. However, observing changes in upper ocean nutrients is challenging because surface concentrations are often below detection limits. We show that the nutricline depth, where nutrient concentrations reach well-detected levels, is tied to productivity and upper ocean nutrient availability. Next, we quantify nutricline depths from a global database of observed vertical nitrate and phosphate profiles to assess contemporary trends in global nutrient availability (1972–2022). We find strong evidence that the P-nutricline (phosphacline) is mostly deepening, especially throughout the southern hemisphere, but the N-nutricline (nitracline) remains mostly stable. Earth System Model (ESM) simulations support the hypothesis that reduced iron stress and increased nitrogen fixation buffer the nitracline, but not phosphacline, against increasing stratification. These contemporary trends are expected to continue in the coming decades, leading to increasing phosphorus but not nitrogen stress for marine phytoplankton, with important ramifications for ocean biogeochemistry and food web dynamics.
Creation, stabilization, and investigation at ambient pressure of pressure-induced superconductivity in Bi
0.5
Sb
1.5
Te
3
Authors: Deng Liangzi , Wang Busheng , Halbert Clayton , Schulze Daniel J. , Gooch Melissa , Bontke Trevor , Kuo Ting-Wei , Shi Xin , Song Shaowei , Salke Nilesh , Yang Hung-Duen , Ren Zhifeng , Hemley Russell J. , Zurek Eva , Prasankumar Rohit P. , Chu Ching-Wu
Published: February 2025

In light of breakthroughs in superconductivity under high pressure, and considering that record critical temperatures (T
c
s) across various systems have been achieved under high pressure, the primary challenge for higher T
c
should no longer solely be to increase T
c
under extreme conditions but also to reduce, or ideally eliminate, the need for applied pressure in retaining pressure-induced or -enhanced superconductivity. The topological semiconductor Bi
0.5
Sb
1.5
Te
3
(BST) was chosen to demonstrate our approach to addressing this challenge and exploring its intriguing physics. Under pressures up to ~50 GPa, three superconducting phases (BST-I, -II, and -III) were observed. A superconducting phase in BST-I appears at ~4 GPa, without a structural transition, suggesting the possible topological nature of this phase. Using the pressure-quench protocol (PQP) recently developed by us, we successfully retained this pressure-induced phase at ambient pressure and revealed the bulk nature of the state. Significantly, this demonstrates recovery of a pressure-quenched sample from a diamond anvil cell at room temperature with the pressure-induced phase retained at ambient pressure. Other superconducting phases were retained in BST-II and -III at ambient pressure and subjected to thermal and temporal stability testing. Superconductivity was also found in BST with T
c
up to 10.2 K, the record for this compound series. While PQP maintains superconducting phases in BST at ambient pressure, both depressurization and PQP enhance its T
c
, possibly due to microstructures formed during these processes, offering an added avenue to raise T
c
. These findings are supported by our density-functional theory calculations.
Longitudinal wave propagation determination in concrete specimen under impact loading by ultrahigh-speed camera image sequence and strain gauge data analysis
Authors: Duran Vergara Laura Camila , Leicht Lena , Beckmann Birgit , Maas Hans-Gerd
Published: February 2025

To demonstrate the potential of an ultrahigh-speed camera with frame rates beyond a million images per second for high dynamic material analysis, cylindrical concrete specimens are tested under compression at strain rates up to 164.3 s−1 in a split Hopkinson pressure bar facility. The evaluation includes the determination of the actual longitudinal wave propagation velocity and the induced longitudinal deformations. The results obtained from image sequence analysis are validated with those obtained by the well-established strain gauge measuring technique that estimate the specimen deformation in the same facility. Data analysis for both measuring techniques is based on the one-dimensional wave theory. Image quality challenges affecting the material analysis are overcome by applying a Bézier fitting filter to the image sequences. Using the image-sequence-based approach to select stress-wave-induced motion points, different wave characteristics are acquired. Subsequently, selecting the points in compression during the first stress wave transit yields longitudinal wave propagation velocities up to 2995  m s−1 with a standard deviation of 265 m s−1. From the validation results, first, an observed bilateral complementarity of both techniques enables a comprehensive analysis of the specimen deformation. Second, individual discrepancies between the material properties obtained from both techniques up to ultimate compressive strength for deformation, velocity, strain, and stress of 20.8 %, 14.4 %, 8.3 %, and 10.0 %, respectively, are achieved.
Detecting the droplet and bubble in the oil-gas-water three-phase medium via ultrasonic A-scan signal-assisted B-mode imaging method
Authors: TIAN Sheng , Tan Chao , Zhang Zhixing , Dong Feng
Published: February 2025

Accurately detecting the parameters of bubbles and droplets in the oil-gas-water three-phase medium is essential to critical decision-making about industrial production. An ultrasonic A-scan signal-assisted B-mode imaging (AS-assisted-BI) method that combines a B-mode imaging (BI) method and an A-scan signal (AS) method is developed to simultaneously visualize the oil-gas-water three-phase medium, distinguish the gas bubble and oil droplet, and measure the parameters about their sizes and locations. The applicability of the plane wave imaging (PWI) method for visualizing the oil-gas-water three-phase medium with less computational cost was confirmed. Then, the influence of the bubble and droplet characteristics, such as acoustic impedance difference, size, and location, upon the ultrasonic propagation mechanism are studied to understand the B-mode image and A-scan signal as the design basis of the BI and AS method. The BI method locates the least key points from the B-mode image based on the PWI method compared with the conventional industrial B-mode image method. The AS method automatically locates the key point from the A-scan signal rather than manually marking it in the previous study. Two options for the AS-assisted-BI method, suitable for different detection requirements and applications, have been designed. The numerical simulation and experimental results demonstrated that the proposed method received excellent precision, robustness, and efficiency for detecting the acoustic impedance difference between the bubble and droplet, the longitudinal location of the bubble front surface, and the droplet’s size and center location.
In-vitro and microdosimetric study of proton boron capture therapy and neutron capture enhanced proton therapy
Authors: Jacobsen Villads , Pan Vladimir A , Tran Linh T , Vohradsky James , Bønnelykke Jonas , Schmidt Herø Cecilie , Johansen Jacob G , Tobias Frederiksen Anders , Singers Sørensen Brita , Busk Morten , Sauerwein Wolfgang A G , Rosenfeld Anatoly B , Bassler Niels
Published: February 2025

Objective. The clinical advantage of proton therapy, compared to other types of irradiations, lies in its reduced dose to normal tissue. Still, proton therapy faces challenges of normal tissue toxicity and radioresistant tumors. To combat these challenges, proton boron capture therapy (PBCT) and neutron capture enhanced particle therapy (NCEPT) were proposed to introduce high-LET radiation in the target volume. Approach. In this work, we performed in-vitro experiments with a V79 cell line to validate PBCT and introduced a novel approach to use NCEPT in proton therapy. We quantified the effectiveness of PBCT and NCEPT with microdosimetric measurements, Monte-Carlo simulations and microdosimetric kinetic RBE model (MKM). Main results. No RBE increase was observed for PBCT. With the use of a tungsten spallation source, enough neutrons were generated in the incoming proton beam to measure significant neutron capture in the microdosimeter. However, no significant increase of RBE was detected when conventional in vitro protocol was followed. The resulting cell deactivation based RBE for NCEPT was found to be heavily dependent on which criteria was used to determine surviving colonies. Significance. PBCT and NCEPT are two proposed treatment modalities that may have the potential to expand the cases in which proton therapy can be beneficial. Understanding the scope of these treatment methods and developing measurement protocols to evaluate and understand their RBE impact are the first step to quantify their potential in clinical context.