bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolutionary dynamics of cooperation driven by a mixed update rule in structured prisoner’s dilemma games
Authors: Lin Longhao , Li Chengrui , Chen Xiaojie
Published: February 2025

How to understand the evolution of cooperation remains a scientific challenge. Individual strategy update rule plays an important role in the evolution of cooperation in a population. Previous works mainly assume that individuals adopt one single update rule during the evolutionary process. Indeed, individuals may adopt a mixed update rule influenced by different preferences such as payoff-driven and conformity-driven factors. It is still unclear how such mixed update rules influence the evolutionary dynamics of cooperation from a theoretical analysis perspective. In this work, in combination with the pairwise comparison rule and the conformity rule, we consider a mixed updating procedure into the evolutionary prisoner’s dilemma game. We assume that individuals adopt the conformity rule for strategy updating with a certain probability in a structured population. By means of the pair approximation and mean-field approaches, we obtain the dynamical equations for the fraction of cooperators in the population. We prove that under weak selection, there exists one unique interior equilibrium point, which is stable, in the system. Accordingly, cooperators can survive with defectors under the mixed update rule in the structured population. In addition, we find that the stationary fraction of cooperators increases as the conformity strength increases, but is independent of the benefit parameter. Furthermore, we perform numerical calculations and computer simulations to confirm our theoretical predictions.
High performance BAW resonators with improved AlN thin films quality based on BaF2 buffer layer
Authors: Zhi Guowei , Xu Kaibin , Chen Zhipeng , Luo Tianyou , Yi Xinyan , Li Guoqiang
Published: February 2025

The quality of AlN thin films has an important effect on the performance of bulk acoustic wave (BAW) resonators. In this work, the low lattice mismatch of BaF2 buffer layer with AlN thin films was employed to improve the crystalline quality of AlN thin films. Furthermore, an ethanol assisted epitaxial liftoff (ethanol-ELO) technique based on the BaF2 buffer layer was proposed to lift off AlN thin films from Si substrate, which reduced surface roughness scattering. The ELO technology reduced the damage of AlN thin films and Si wafer during the ELO process due to the selective etching of AlN and BaF2. Utilizing the BaF2 buffer layer, the as-prepared BAW resonators, based on single-crystalline AlN, displayed Q-factor up to 2857, which was 47% higher than that without the BaF2 buffer layer. This study highlights the significant role of the BaF2 buffer layer in enhancing BAW resonators' performance and reducing fabrication costs.
Research progress on the principle and application of metalenses based on metasurfaces
Authors: Zhao Feifan , Jing Xufeng , Yu Mingzhou
Published: February 2025

The metalens discussed in this article is a planar optical device built on metasurfaces, utilizing precisely engineered subwavelength nanostructured wires to manipulate electromagnetic waves. This enables precise control over the phase, amplitude, and polarization of these waves. Recent advancements in metalens research primarily focus on their design principles, performance optimization, imaging enhancement, manufacturing techniques, and various application domains. This article reviews the progress in metalens development, highlighting their design principles across different frequency bands and their applications in science and technology. Future research directions are expected to emphasize material innovation, simplification of manufacturing processes, and further performance improvements to drive their adoption in cutting-edge fields.
Deformation damage mechanism and strength criterion of columnar jointed rock mass under true triaxial condition
Authors: Lu Wenbin , Zhang Dong , He Yanxin , Tuo Zhiwei
Published: February 2025

To accurately understand the anisotropic mechanical properties of columnar jointed basalt distributed in the Baihetan Hydropower Station, indoor true triaxial loading physical model tests were conducted with different joint angles (β = 0°–90°) to study the strength deformation and failure mode of columnar jointed rock mass (CJRM). The results indicate that the strength anisotropy characteristics of CJRM under different stress environments are significant. The peak strength shows a U-shaped (σ2 = 2 MPa, σ2 = 4.5 MPa), W-shaped (σ2 = 3 MPa), and linearly increasing (σ2 = 5 MPa) rule of change. The increments in peak strength of CJRM varied significantly with the intermediate principal stresses, with average increments of 29.0% (σ2/σ3 = 1.5), 48.8% (σ2/σ3 = 2.25), and 45.4% (σ2/σ3 = 2.5); ε3 increases and then decreases with the change of inclination angle β, and the shear expansion phenomenon increases, ε2 decreases and then increases with the β, and the deformation characteristics of CJRM are that the expansion deformation transforms into compression deformation. The increase in σ2 shifts the rock features from moderate anisotropy to low anisotropy. According to the damage characteristics, the CJRM are classified according to three damage modes: (a) structurally controlled, (b) stress-controlled, and (c) stress-structurally controlled. Finally, Mogi–Coulomb strength criterion and Drucker–Prager strength criterion, which are applicable to true triaxial stress conditions, were used to verify the experimental results. The Mogi–Coulomb strength criterion fitted the strength parameters c and φ values, which showed a high degree of agreement with the in situ test results on site, indicating good applicability. The research results can scientifically and accurately predict and evaluate the stability of the Baihetan project.
Study on evolution characteristics of energy dissipation and vortex in pump-turbine during load rejection transition process
Authors: Lu Yonggang , Liu Zhiwang , Zhao Yun , Wang Zhengwei , Presas Alexandre
Published: February 2025

The widespread adoption of intermittent wind and solar energy sources disrupts the stability of power grids, necessitating frequent load rejection processes for pump-turbine. This jeopardizes the stability of pump-turbine units. To investigate the operating behavior of pump-turbine units during load rejection, this study focuses on a Francis reversible pump-turbine. Employing the results from a one-dimensional characteristic line method as boundary conditions, three-dimensional numerical simulations are conducted. The entropy production theory was employed to quantify energy loss in different components, including direct dissipation, turbulent dissipation, and wall shear stress. And the pressure load curves of runner blades at different spans are extracted. The flow characteristics, entropy production losses, and pressure loads within the passage are analyzed at various moments during the load rejection process. Results demonstrate that when a unit undergoes load rejection, it repeatedly transitions into and out of the S-characteristic region. The flow state within the passage is most unfavorable under reverse pump conditions, with the entropy production loss reaching its maximum value of 339 160 W/K. When the unit's rotational speed increased beyond 1.1nd, the unit's water thrust and torque underwent drastic changes. Moreover, the pressure load undergoes significant variations under runaway conditions, with the pressure load difference among various blades reaching up to 33 000 kPa. These findings provide a scientific basis for ensuring the safe and reliable operation of pump-turbine units during load rejection processes.
On the performance of QTP functionals applied to second-order response properties
Authors: Mendes Rodrigo A. , Windom Zachary W. , Kim Hyunsik , Bartlett Rodney J.
Published: February 2025

Correlated orbital theory (COT) is an exact one-particle treatment that adds essential electron correlation into its molecular orbitals, potentially reducing correlated treatments of response properties to one-particle coupled-perturbed Hartree–Fock- or Kohn–Sham-like calculations. Such a computation is vastly simpler than the usual ab initio correlated approach that would add correlation typically with EOM-CC after a perturbed mean-field solution. The question then is, how well can this be accomplished via the Quantum Theory Project (QTP) exchange–correlation (XC) functionals that are meant to emulate the rigorous COT framework? This paper addresses this question for response properties by making comparisons between such orbital-specific calculations and those from well-correlated EOM-CC solutions for static polarizabilities, nuclear magnetic resonance coupling constants, and chemical shifts. The simple orbital-specific version provides an accurate realization of the correlated EOM-CC results, but now in a mode that facilitates an orbital-by-orbital interpretation. Here, we compare 33 XC functionals from the different Jacob’s ladder rungs always against the EOM-CCSD results. Thus, the smallest mean absolute deviation for the static polarizability comes from LC-QTP XC, 0.28 a.u. Regarding the total nuclear spin–spin coupling constants, QTP01 performs best, %Error = 10.63% (QTP02 and LC-QTP are second and third best). Finally, the XC that stood out in the chemical shift analysis was TPSS0, which presented the best result for the majority of the chemical shifts. However, considering the overall performances based on linear fitting of all isotope data points, five functionals are recommended for a chemical shift study: TPSS0, ωB97X, QTP00, QTP01, and QTP02, all presenting R2 = 0.96.
Microscopic dynamics of enhanced glass-forming ability with minor oxygen addition in bulk metallic glasses
Authors: Yang Kun , Qin Hairong , Huang Haishen , Zhu Yong , Lü Yongjun
Published: February 2025

Minor oxygen addition has been proposed as a promising strategy to enhance the performance of metallic glasses, particularly their glass-forming ability. In this work, we investigate the microscopic dynamics of a CuZr glass former with oxygen content up to 2 at. % using molecular dynamics simulations based on specially developed neural network interatomic potentials. Our findings indicate a gradual increase in the glass transition temperature with oxygen addition, with an anomalous peak at 0.4 at. % O. We reveal an anti-correlation of kinetic fragility and dynamic heterogeneity behind this unusual rise, where the system exhibits reduced kinetic fragility alongside more significant dynamic heterogeneity. Using the continuous time random walk method, we show that at 0.4 at. % O, a highly mobile Cu atomic layer forms around O–Zr clusters, resulting in notable dynamic heterogeneity. This dynamic behavior is closely linked to the bonding pattern within the O–Zr network, particularly favoring the configuration with edge and surface sharing. In addition, such structures contribute to a more compact O–Zr network, leading to lower kinetic fragility. These findings provide detailed insights into the microscopic dynamics behind the effects of minor oxygen additions.
Spatial reciprocity under reinforcement learning mechanism
Authors: Wang Lu , Shi Xiaoqiu , Zhou Yang
Published: February 2025

At present, the research on the dynamics of cooperative behavior of agents under reinforcement learning mechanism either assumes that agents have global interaction, that is, agents interact with all other agents in the population, or directly study the influence of relevant factors on cooperation evolution based on the local interaction in a network structure. It neglects to formally study how the limitation of agents that only interact with local agents affects their strategy choice. Thus, in this paper, we study the cooperative behavior of agents in a typical social decision-making environment with conflicts between individual interests and collective interests. On the one hand, a programmed game model in game theory, namely, prisoner’s dilemma game, is used to capture the essence of real-world dilemmas. On the other hand, the effects of local and global strategy learning on the cooperative evolution of agents are investigated separately, and the nature of spatial reciprocity under the reinforcement learning mechanism is found. Specifically, when there is no inherent connection between the interacting agents and the learning agents within the system, the network structure has a limited effect on promoting cooperation. It is only when there is an overlap between the interacting agents and the learning agents that the spatial reciprocity effect observed in the traditional evolutionary game theory can be fully realized.
Extreme events in the Higgs oscillator: A dynamical study and forecasting approach
Authors: M Wasif Ahamed , R Kavitha , V Chithiika Ruby , M Sathish Aravindh , A Venkatesan , M Lakshmanan
Published: February 2025

Many dynamical systems exhibit unexpected large amplitude excursions in the chronological progression of a state variable. In the present work, we consider the dynamics associated with the one-dimensional Higgs oscillator, which is realized through gnomonic projection of a harmonic oscillator defined on a spherical space of constant curvature onto a Euclidean plane, which is tangent to the spherical space. While studying the dynamics of such a Higgs oscillator subjected to damping and an external forcing, various bifurcation phenomena, such as symmetry breaking, period doubling, and intermittency crises are encountered. As the driven parameter increases, the route to chaos takes place via intermittency crisis, and we also identify the occurrence of extreme events due to the interior crisis. The study of probability distribution also confirms the occurrence of extreme events. Finally, we train the long short-term memory neural network model with the time-series data to forecast extreme events.
Dynamic characteristics of oblique droplet impact on a liquid film
Authors: Bao Minle , Yi Zhihao , Zhao Denghui , Liu Hui , Guo Yali , Gong Luyuan , Shen Shengqiang
Published: February 2025

The impact of droplets on liquid films is a fundamental phenomenon in fluid dynamics, with significant implications across various scientific and engineering applications. While much research has focused on normal droplet impacts, where the droplet strikes the liquid surface perpendicularly, the dynamics of oblique droplet impacts remain less understood. This study aims to explore the complex interactions governing oblique droplet impacts on the liquid film. Based on superhydrophobic coating technology, this study proposes a novel experimental method for achieving oblique droplet impacts. Compared to existing methods, this approach offers good experimental repeatability. The experimental setup developed is centered around a droplet generation unit capable of stably producing oblique droplets, with the evolution of the ship's prow-like liquid crown captured using high-speed imaging technology. The effects of the Weber number, impact angle, and liquid film thickness on the evolution and characteristic parameters of the liquid crown were investigated. The model for predicting the variation of the dimensionless liquid crown radius was validated. Additionally, a splashing discrimination method based on the normal K number was introduced, and an empirical correlation for the splashing threshold was established using the soft-margin support vector machine. The findings of this study could pave the way for innovative solutions in industries where precise fluid control is paramount and lay the groundwork for future explorations into more intricate multiphase flow phenomena.
Electronic properties of metamorphic GaSbBi films on GaAs
Authors: Hilska Joonas , Puustinen Janne , Koivusalo Eero , Guina Mircea
Published: February 2025

We report on the electronic, structural, and optical properties of epitaxial GaSbBi films with varying Bi-concentration (up to 7%Bi) grown on semi-insulating GaAs(100) substrates. The 1 μm thick GaSbBi epilayers exhibit fully relaxed narrow x-ray diffraction peaks and smooth surface morphology comparable to that of high-quality GaSb epilayers on GaAs. Low temperature photoluminescence spectra exhibit bandgap shrinkage consistent with Bi alloying. Electrical Hall measurements indicate a reduction in hole concentration and no change in the hole mobilities with increasing Bi content for the nominally undoped GaSbBi alloy. The residual hole concentration reduces from the 1018 cm−3 level for a reference GaSb sample to the low 1017 cm−3 level with increasing Bi content. Hole mobility values of around 300 cm2/Vs are observed independent of the Bi content. These dependencies are attributed to the Bi surfactant effect and Bi-induced defect formation.
Strongly perturbed bondorbital attractors for generalized systems
Authors: Dlamini A. , Doungmo Goufo E. F. , Khumalo M.
Published: February 2025

This paper analyzes a generalized chaotic system of differential equations characterized by attractors with bondorbital structures. Both classical and fractional-order cases are examined analytically and numerically, with convergence and stability analyses provided. The numerical findings confirm the presence of bondorbital attractors in the classical system. In contrast, bondorbital attractors also emerge in the fractional model employing the Caputo–Fabrizio operator, albeit with significant perturbations for specific fractional orders. To validate these results, an electric circuit implementation of the fractional-order system using an field-programmable gate array board was conducted, yielding consistent outcomes. This study highlights the potential of fractional calculus, particularly the Caputo–Fabrizio operator, in capturing the memory effects and complex dynamics of chaotic systems. The work bridges theoretical modeling and practical hardware applications, offering valuable insights for modeling complex systems.
Damage characteristics of high-temperature sandstone impacted by cetyltrimethylammonium bromide-enhanced jet
Authors: Ge Zhaolong , Zhang Xu , Zhou Zhe , Li Mengli , Chang Wenxu , Shangguan Jianming
Published: February 2025

High-pressure water jet technology is an efficient and eco-friendly method with the potential to enhance rock-breaking efficiency in deep-earth high-temperature environments. This study introduces the use of the surfactant cetyltrimethylammonium bromide (CTAB) in water jets to improve thermal exchange between low-temperature jets and high-temperature rocks, aiming to optimize rock-breaking efficiency under high-temperature conditions in deep reservoirs. Experiments were conducted using jets with varying CTAB concentrations impacting rock at different temperatures to assess the feasibility and elucidate the underlying rock-breaking mechanisms. Computed Tomography (CT) combined with three-dimensional reconstruction was employed to establish the internal damage field of the rock, thereby analyzing the jet rock-breaking mechanisms. The findings indicate that the erosion pit formed in sandstone under the impact of a pure water jet has a regular inverted “Ω”-shape, while the pit formed under CTAB-enhanced jets resembles a “J”-shape. Furthermore, at elevated rock temperatures, the depth and volume of erosion pits created by jet impacts are greater than those at room temperature. At 100 °C, the rock-breaking volume increases by 16.81% with a pure water jet, whereas it increases by 75.46% with a jet containing 500 ppm CTAB. Optimal concentrations of CTAB additives range from 500 to 1000 ppm, substantially enhancing rock-breaking efficiency at high temperatures by bolstering heat exchange between the jet and rock and intensifying the water wedge effect. These findings provide a theoretical basis and novel approaches for hydraulic fracturing of deep, high-temperature hard rock.
Impacts of acoustic impedance of a perforated plate on near-wall turbulence
Authors: Hoang Van Thuan , Jafari Azadeh , Cazzolato Benjamin , Arjomandi Maziar
Published: February 2025

In this paper, the impact of wall acoustic impedance on near-wall turbulence of boundary layers is presented. Different acoustic impedances of a perforated plate with a backing cavity are used to control near-wall turbulence. It was shown that the specific acoustic impedance of the perforated plate correlates with sweeps and ejections in the near-wall region. A reduction of up to 7.8% in sweep intensity and 7% in ejection intensity was observed at a normalized specific acoustic reactance of 69.6 and an impedance angle of approximately 0.5π, which is associated with a reduction of about 7% in the inner peak of the turbulence intensity profiles. At this impedance angle, the wall-normal velocity is in phase with the pressure at the wall leading to transpiration through the perforated plate. This transpiration decreases the near-wall cycles by interacting with sweep and ejection events and reducing their effects. Consequently, turbulence intensity, shear stress in the near-wall region, and local friction drag are all reduced.
Electronic structures and spin frustration in Ln3O (Ln = Ce, Sm, Gd) neutrals and anions determined by anion photoelectron spectroscopy
Authors: Huizenga Caleb D. , Vaish Shivangi , Thompson Lee M. , Jarrold Caroline Chick
Published: February 2025

The results of a combined experimental and computational study on Ln3O (Ln = Ce, Sm, and Gd) anion and neutral clusters are presented and analyzed. These three Ln’s were specifically targeted because they vary in their spin state and orbital angular momentum associated with the 4fN subshell occupancies. From the anion PE spectra of Ce3O−, Sm3O−, and Gd3O− measured with 2.330 and 3.495 eV photon energies, we determine the adiabatic electron affinities of the corresponding neutrals to be 0.83 ± 0.03, 1.11 ± 0.05, and 1.17 ± 0.05 eV, respectively. The lowest energy features in all three spectra can readily be reconciled with molecular structures in which the O-atom is central to all three Ln centers, with Ce3O−/Ce3O assuming pyramidal structures and Sm3O−/Sm3O and Gd3O−/Gd3O assuming planar structures. Computationally, the lowest-energy structure of neutral Ce3O is a kite-like structure, which is not consistent with the observed spectrum. The kite-like and pyramidal structures of Ce3O− are predicted to be nearly isoenergetic. Electronic states in which all three 4fN centers are ferromagnetically coupled are predicted to be energetically favored for all species, but spin-frustrated states in which one 4fN center is antiferromagnetically coupled to the remaining centers are computed to lie 0.05 eV higher in energy than the FM-coupled states for Ce3O− and Sm3O−. The PE spectrum of Sm3O− exhibits striking anomalies in the photoelectron angular dependence. This effect is attributed to strong photoelectron–valence electron interactions that drive nominally forbidden changes in the Mf state of the remnant neutral.
Numerical analysis of nucleation effects on cloud cavitation using multiscale Euler–Lagrange model
Authors: Zhang Ben , Qin Xinzhen , Chen Yihong , Shao Xueming , Deng Jian
Published: February 2025

This study develops a hybrid multiscale Euler–Lagrange model to investigate the unsteady characteristics of cloud cavitation around a hydrofoil under different water qualities. A homogeneous mixture model is implemented for macroscopic cavity simulations, tracking the vapor–liquid interfaces. In the Lagrangian framework, the dynamics and motion of nuclei and bubbles are resolved. By incorporating more physically accurate conversion criteria to couple the two frameworks, the cavitation model is modified to ensure consistency with the assumption that cavitation inception arises from the expansion of nuclei. Numerical results, obtained under different size distributions of nuclei populations, align well with experimental data, validating the capability of the multiscale model to account for the effects of water quality. They also offer detailed insights into the influence of cavitation flows on microscale bubble behavior, particularly highlighting the significant role of reentry jets in bubble generation and motion. The results underscore the critical interplay between small-scale bubble dynamics and macroscopic cavitation flows. In addition, a statistical analysis of the size distribution of microbubbles reveals a distribution law consistent with experimental observations. This study provides a robust framework for investigating the comprehensive effects of water quality on cloud cavitation flows, offering a promising avenue for future research in this domain.
Polyampholyte sequence controls the type of electrostatic coil-globule transition in good solvent
Authors: Sinha Karthik C. , Rumyantsev Artem M.
Published: February 2025

Coarse-grained molecular dynamics simulations are employed to explore the conformational behavior of globally neutral polyampholytes under good solvent conditions. The interplay between non-Coulomb repulsions and sequence-dependent Coulomb attractions of monomers results in qualitatively different types of electrostatically driven chain contraction for diblock, random, and alternating statistics. At increasing the solution Bjerrum length lb, diblock and random polyampholytes exhibit a smooth coil-globule crossover, with the globule size continuously decreasing with lb according to the theoretical power laws. This confirms the scaling picture of the globule interior consisting of oppositely charged blobs attracting each other via long-range electrostatic forces and repelling via short-range two-body interactions. In contrast, alternating polyampholytes collapse completely analogously to neutral chains because Coulomb interactions in them are effectively dipole–dipole short-range. The transition region shrinks with increasing chain length, implying phase transition behavior in the limit of infinitely long chains. These collapse curves fall on the universal master curve, which is well-fitted by the theory of coil-globule transitions and demonstrates that Coulomb interactions in alternating polyampholytes renormalize (reduce) the dimensionless second virial coefficient by δB∝−lb2. This study highlights the profound impact of primary sequence on the conformational behavior of charge-balanced polyampholytes in good solvents, particularly the nature of the electrostatically driven coil-globule transition they undergo.
Liquid flow mode transition and hysteresis under passive control
Authors: Duan Runze , Yao He , Dong Jiangfeng , Chen Yadong , Huang Qiannan , Liu Liansheng
Published: February 2025

The liquid flow mode exerts a significant influence on the dynamics of droplet breaking, with consequential effects on factors like droplet size and monodispersity. In various applications, including but not limited to inkjet printing, microcapsule preparation, and cell encapsulation, diverse production methods are employed, but they typically rely on some form of droplet breakup or liquid jet breakup to ultimately generate droplets. During the process of droplet formation, smaller satellite droplets, which are considerably smaller than the main droplet, are inevitably generated. These smaller droplets can lead to wastage of raw materials and reduced production efficiency. Passive control methods, which involve modifications to the structure of the dropper, effectively suppress the formation of satellite droplets, and prove to be more practical and manageable in actual production scenarios when compared to active control methods. In contrast to the jetting mode, the dripping mode of droplet molding exhibits greater stability and size uniformity, thereby better meeting the requirements for particle uniformity in the preparation of traditional Chinese medicine. This paper specifically investigated the transition from the jetting mode to the dripping mode and explored the hysteresis of this transition under the influence of gravity utilizing a passive control method. By incorporating a drainage device within the dropper along with a Y-channel, a drainage system was established to achieve passive control. The effects of the length and diameter of the drainage device, as well as the mass fraction of the solution, on the conversion of flow modes were analyzed.
Numerical study on inverse grading segregation mechanism of single coarse particles with different particle sizes under two-dimensional cyclic shear
Authors: Zhao Lishan , Sun Hao , Liu Meichen , Gao Yanhua , Dai Zongsheng , Zhou Shenggui , Zhao Yusong
Published: February 2025

Granular mixtures with size differences can segregate when subjected to shaking or shear. This study investigates the mechanism underlying the inverse grading segregation of single coarse particles with varying sizes under cyclic shear. A self-developed two-dimensional testing device combined with three-dimensional printing technology and the image identification capabilities of the segment anything model enabled the construction of a cyclic shear numerical model based on rigid blocks. The analysis concentrated on the movement of coarse particles and the evolution of the macroscopic structure of the particle system, and the local topological structures surrounding single coarse particles. The findings reveal the following: (1) Larger coarse particle sizes and lower shape factors under cyclic shear result in shorter times to free surface and higher vertical velocities. (2) Throughout the cycles, the vertical net force acting on each coarse particle fluctuates around zero, while its vertical position displays a zigzag upward trend. (3) Within a single typical cycle, larger coarse particles increase the local void ratio, aiding their lift. Vertical displacement and net force exhibit a double peak pattern inversely related to coordination number, while horizontal displacement fluctuates periodically around zero. (4) Weighted local degree centrality negatively correlates with vertical displacement of single coarse particles, reflecting the dual influence of particle size and importance on segregation velocity. Fine particles occupying the two lower corners of single coarse particles create the lifting effect, driving their zigzag upward motion. Additionally, larger coarse particles enhance their importance, accelerating the segregation process.
Volume measurement and calculation of sessile droplets on inclined planes and spherical external surfaces
Authors: Dong Jian , Zhang Zihao , Gong Mengying , Wu Jie , Liu Bilong
Published: February 2025

This paper puts forward a novel measurement and calculation method for sessile droplets' volumes on inclined planes and spherical external surfaces. The volume of a droplet on an inclined plane or on a spherical external surface, which has a fictitious inclined plane, is determined by its shape factor (β), the maximum distance (d) of the contour points away from the inclined plane, and the plane inclination angle θinc. Using the circular arc differential method of the Bashforth–Adams equation and the image processing technique, the d and β are obtained or calculated out. The theoretical model and its algorithm are set up to calculate the droplet volume. In addition, we do experiments to validate the accuracy of the theoretical model. The experimental results show good agreement with those calculated by the theoretical model. This work is significant and can be used to measure and control volumes of droplets in microfluidic and biomedical technologies.
An oscillation flow mechanism of hypersonic flows over parallel-staged double-wedge configuration
Authors: Wang Yue , Liu Yiming , Li Haojie , Xue Xiaopeng , Wang Yunpeng
Published: February 2025

A two-body model is an essential configuration of the aerospace vehicle, e.g., two-stage-to-orbit vehicle. Unsteady numerical simulations are performed to investigate the hypersonic flow over a parallel-staged double-wedge configuration of the different angles of incidence (AoI) at Mach 7. The effect of the AoI on the unsteady flow is analyzed, and the flow mechanism of the periodic flow oscillation associated with shock interactions is clarified. The unsteady oscillation flowfield is caused by propagation and inversion of the pressure gradient between the upstream and downstream in the interstage clearance. Moreover, the Strouhal number (St) of the oscillation flowfield is determined and analyzed, namely, the dominant nondimensional frequency is 0.20 < St < 0.26, and the oscillation frequency is determined by the propagation's speed and distance of the pressure gradient. Particularly, the flow tends to steady at AoI ≤ 3 deg; else self-sustaining periodic oscillation flow at AoI > 3 deg tends to be stronger with increasing AoI. The mechanism that accounts for the division condition of the AoI whether the steady or unsteady flowfield of the double-wedge configuration is also clarified, namely, the relationship between the local shear layer height and the orbiter's nose height which is governed by the incidence angle determines whether the oscillation flowfield pattern occurs or not.
Superionic conduit of alkaline earth metals confined by two-dimensional boron–carbon layers
Authors: Lv Yang , Li Jianfu , Zhang Zhaobin , Geng Yanlei , Liu Yong , Yuan Jianan , Hu Qingyang , Wang Xiaoli
Published: February 2025

Superionic conductors feature fast super-ion diffusion in the solid-state framework, making them ideal materials for safe, high-performing electrolytes. It is, therefore, in hot pursuit of seeking solid-state electrolyte materials with high energy density and flexible operation conditions. Here, we verified a class of two-dimensional superionic conduction in A(BC)2, in which A are alkaline earth metals such as Be, Mg, and Ca, and boron–carbon (BC) form graphene-like layers. Our first-principles molecular dynamics simulation, boosted by high-accuracy machine-leaning potentials, shows that alkaline metal becomes super-ions under high-temperature conditions, moving freely between BC layers. Differences in superionic conduit lead to the diffusion in Be(BC)2 driven by the vacancy mechanism. In contrast, the diffusion in Mg(BC)2 and Ca(BC)2 is jointly driven by both the vacancy and cooperative mechanisms. We demonstrate that the superionic transition temperature is controlled by the deficiency of mobile super-ions, tuning from 1300 to 1600 K, with up to 2.5% cation defects. With superior thermal stability, these two-dimensional compounds are promising electrolyte materials with ultrahigh heat resistivity capable of operating under high-temperature environments such as deep drills and aerospace devices.
Josephson coupling in lanthanum-based cuprate superlattices
Authors: Ahmad H. G. , Massarottti D. , Tafuri F. , Logvenov G. , Bianconi A. , Campi G.
Published: February 2025

In most anisotropic compounds such as bismuth-based layered cuprate perovskites, the supercurrent across the blocking layer is of Josephson type, and a single crystal forms a natural stack of Josephson junctions. Here, we report on the evidence of Josephson-like transport in an artificial cuprate superlattice composed of 10 LaSrCuO–LaCuO repeats, creating a superlattice of junctions, where LCO is a superconducting Mott insulator and LSCO is an overdoped metal. The superlattice has been designed with a long period of d = L + W = 5.28 nm, with L and W being the thicknesses of LCO and LSCO units, respectively, and is in the underdoped regime with an average doping level of ⟨δ⟩ = 0.11. Quantum-size effects and Rashba spin–orbit coupling are controlled by L/d = 0.75, with a quasi-2D superconducting transition temperature of 41 K and a c-axis coherence length of about 1.5 nm. Measurements at very low temperatures show evidence of Josephson phase dynamics consistent with very low Josephson coupling and a phase diffusion regime, thus explaining why Josephson coupling in LSCO superlattices has been so elusive. The tuning of LSCO superlattices in the Josephson regime enriches the phase diagram of HTS.
Spectral principle for frequency synchronization in repulsive laser networks and beyond
Authors: Honari-Latifpour Mostafa , Ding Jiajie , Belykh Igor , Miri Mohammad-Ali
Published: February 2025

Network synchronization of lasers is critical for achieving high-power outputs and enabling effective optical computing. However, the role of network topology in frequency synchronization of optical oscillators and lasers remains not well understood. Here, we report our significant progress toward solving this critical problem for networks of heterogeneous laser model oscillators with repulsive coupling. We discover a general approximate principle for predicting the onset of frequency synchronization from the spectral knowledge of a complex matrix representing a combination of the signless Laplacian induced by repulsive coupling and a matrix associated with intrinsic frequency detuning. We show that the gap between the two smallest eigenvalues of the complex matrix generally controls the coupling threshold for frequency synchronization. In stark contrast with attractive networks, we demonstrate that local rings and all-to-all networks prevent frequency synchronization, whereas full bipartite networks have optimal synchronization properties. Beyond laser models, we show that, with a few exceptions, the spectral principle can be applied to repulsive Kuramoto networks. Our results provide guidelines for optimal designs of scalable optical oscillator networks capable of achieving reliable frequency synchronization.
Prevent sand accumulation under the windbreak wall along railways in strong wind areas
Authors: Xin Guowei , Yang Zhen , Qi Yanlu , Zhang Xiaobin , Han Guowen
Published: February 2025

The Lanxin High-Speed Railway is the world's first high-speed railway to pass through a strong wind region. Many windbreaks were installed along the railway line to reduce the adverse effects of wind on passing trains. The windbreak wall blocks strong wind, reduces the velocity of sand particles, and minimizes sand accumulation on the track. This paper proposes a solution based on fluid mechanics and the two-phase flow of wind and sand to reduce sand accumulation on railway tracks. Wind tunnel experiments and numerical simulations are conducted for three scenarios: the existing windbreak wall and a 45-degree inclined board installed at the wall's top or the leeward side. The results show that the sand accumulation and wind speed are higher on the windward side. The largest sand accumulation occurs when the 45-degree inclined plate is installed at the top and the wind speed is 15 m/s. The sand accumulation on the track is the lowest, the negative wind speed is the highest when the 45-degree inclined plate is located at the top on the windward side, and the wind speed is 30 m/s. Sand accumulation on the track can be minimized by taking advantage of the highly turbulent area. The sand particle size on the actual track is lower than the average sand particle size at the start of the sand bed. Our results can be used to optimize measures to prevent or minimize sand accumulation in railway lines and towns in windy areas and mitigate desertification.
Regulation of high-frequency vibrations via phononic crystal structure with zero Poisson’s ratio
Authors: Li Bingxue , Jiang Xiongzhi , Li Yangbo , Huang Yuefan , Zhang Qiuju , Tao Zhiqiang , Hu Yutao , Liu Xinting
Published: February 2025

Vibration affects the service life of engineering structures and the working accuracy of instruments, causing engineering accidents such as structural collapse and equipment explosion. Phononic crystals can effectively suppress the propagation of elastic waves within the bandgap frequency range. In this study, based on the local resonance theory, a phononic crystal structure with zero Poisson’s ratio was designed by combining two classical structures: concave and chiral structures. The structure shows good zero Poisson’s ratio performance and a suppression effect on high-frequency vibration frequencies. Through numerical simulation and low-amplitude transmission tests, by changing the structure scale and material type, we realized an adjustable bandgap of the designed structure and confirmed the reliability of the results. Its structural design and research results provide new ideas for preventing high-frequency vibrations in industrial processes and provide reference values for the development of phononic crystals.
The changing law of underwater explosion shock wave parameters with hydrostatic pressure
Authors: Xu Qingtao , Ma Honghao , He Ze
Published: February 2025

The effects of hydrostatic pressure on shock wave parameters were analyzed by using a combination of experiments and numerical simulations in this paper. The functional relationship between the overpressure peak and hydrostatic pressure was established, and the functional expression between the slope of the linear change and the specific distance was obtained. Underwater explosion experimental data were obtained for 0.3 g Pentaerythritol Tetranitrate (PETN) under four working conditions with initial pressures of 0.1, 0.25, 0.5, and 1 MPa. The underwater explosion of 0.3 g PETN was simulated under 11 working conditions with initial pressures ranging from 0.1 to 30 MPa using ANSYS software. In the simulation, the effects of water depth on the density of the water medium and the speed of sound were considered. The accuracy of the simulation was verified in comparison with the experimental data. According to the simulation results, the overpressure peak of the shock wave (the difference between the positive shock wave pressure and hydrostatic pressure), the decay characteristic time θ, the propagation speed, the impulse, and the specific shock energy with the change rule of hydrostatic pressure can be obtained. The results show that the decay characteristic time θ, the impulse, and the specific shock energy decreased with increasing hydrostatic pressure, and the decay amount increased with increasing distance. The overpressure peak of the shock wave and propagation speed linearly change with increasing hydrostatic pressure, and as the distance increases, the increase in the overpressure peak value decreases.
Noninvasive photoacoustic synergistic measurement of vascular morphology and blood flow velocity
Authors: Lin Zhanle , Hu Feifan , Zhang Hao , Shan Wanru , Li Dong , Chen Bin , Yao Liang , Zheng Yuping
Published: February 2025

Photoacoustic imaging is a multimodal imaging technique combining optical and acoustic principles to observe and analyze structural and functional tissue information. This study presents a photoacoustic velocimetry and imaging experimental system for synergistic measurement of vascular morphology and blood flow velocity. The system, equipped with a 532 nm pulsed laser and optical-acoustic combiner, achieves a horizontal resolution of 10 μm. It measures flow velocities ranging from 25 to 200 mm/s with an average error of 8.2%. Through two-dimensional scanning and Gaussian filtering, the vascular morphology was reconstructed with a Dice Similarity Coefficient of 0.92. Compared to conventional imaging systems, the proposed system enhances small vessel resolution by up to 40% and achieves a signal-to-noise ratio improvement of 7 dB. These results highlight the system's potential for precise and noninvasive biomedical applications, including real-time diagnosis and monitoring. Vascular imaging plays a critical role in biomedical research, aiding in understanding vascular structure and function and exploring cardiovascular diseases, tumor angiogenesis, hemodynamics, and other related diseases. Noninvasive imaging techniques can evaluate disease progression and therapy efficacy. Accurate blood flow measurement is essential for diagnosing various diseases, including stroke, diabetes, and cancer. This work demonstrates a synergistic photoacoustic system capable of achieving high-resolution vascular imaging and flow velocity measurements.
The Regulatory-associated protein of target of rapamycin 1B (RAPTOR 1B) interconnects with the photoperiod pathway to promote flowering in
Arabidopsis
Authors: Urrea-Castellanos Reynel , Calderan-Rodrigues Maria J. , Artins Anthony , Musialak-Lange Magdalena , Macharanda-Ganesh Appanna , Fernie Alisdair R. , Wahl Vanessa , Caldana Camila
Published: February 2025

The transition from vegetative to reproductive growth, or floral transition, is a tightly regulated, energy-demanding process. In
Arabidopsis
, the interplay of light perception and circadian rhythms detects changes in photoperiod length, accelerating flowering under long days (LD). CONSTANS (CO), a transcription factor, upregulates FLOWERING LOCUS T (FT) in leaves during dusk. The FT protein then moves to the shoot apical meristem, triggering the floral transition. While light and circadian signals control CO protein levels, less is known about how the nutrients/energy sensing regulates the photoperiod pathway for flowering modulation in this process. In our study, we identify the contribution of the Regulatory-associated protein of target of rapamycin 1B (RAPTOR1B), a component of the nutrient-sensing TOR complex (TORC), in the induction of specific flowering genes under CO control. While transcription of CO remains unaffected in
raptor1b
mutants, a reduction in its protein levels at dusk is observed compared to the wild type. Remarkably, the mutant also exhibits compromised GIGANTEA (GI) protein levels, crucial for CO stabilization during dusk. Our results indicate that the interaction and colocalization of RAPTOR1B with GI in the nucleus might influence GI levels through an unknown posttranscriptional mechanism. Genetic crosses position RAPTOR1B upstream of CO and GI. This is supported by phenotypic and molecular analyses. Our findings demonstrate that RAPTOR1B, likely as part of TORC, contributes to the photoperiod pathway of the flowering network, ensuring the timely initiation of floral transition under LD conditions.
The estimated cost of preventing extinction and progressing recovery for Australia’s priority threatened species
Authors: Ward Michelle , Possingham Hugh P. , Wintle Brendan A. , Woinarski John C. Z. , Marsh Jessica R. , Chapple David G. , Lintermans Mark , Scheele Ben C. , Whiterod Nick S. , Hoskin Conrad J. , Aska Bora , Yong Chuanji , Tulloch Ayesha , Stewart Romola , Watson James E. M.
Published: February 2025

The global extinction crisis is intensifying rapidly, driven by habitat loss, overexploitation, climate change, invasive species, and disease. This unprecedented loss of species not only threatens ecological integrity but also undermines ecosystem services vital for human survival. In response, many countries have set ambitious conservation targets such as halting species extinctions, yet the necessary financial commitments to achieve this are rarely prescribed. Estimating costs can be achieved using an ensemble of spatially variable species-specific cost models for threat abatement activities. We employ this method to provide a cost assessment to halt extinctions for Australia’s priority terrestrial and freshwater species. We show that it will cost ~AUD15.6 billion/year for 30 y to halt extinctions for these 99 priority species (comparable to 1% of Australia’s GDP). The more ambitious objectives to move priority species down one threat category (~AUD103.7 billion/year) or remove from the threatened species list entirely (~AUD157.7 billion/year) would require considerably more investment. Regardless of what is spent, we found that 16 (16%) priority species could not be removed from the threatened species list due to extensive historical declines and pervasive, ongoing, unmanageable threats, such as climate change. But implementing these efforts could ensure conservation benefits for over 43% of all nationally listed nonmarine threatened species. Adequate funding is crucial for meeting government commitments and requires both government leadership and private sector investment.