arXiv subjects

Shuiqing Li

Publications and source records attributed to Shuiqing Li.

14 recordsLinked to original sources

arXiv2025

Synergetic Enhancement on Bulk and Grain Boundary Ionic Conduction of Mg Doped High-Entropy NASICON-Type Solid Electrolyte for Solid-State Na+ Batteries by Spray Flame Synthesis

All-solid-state sodium batteries represent a promising next-generation energy storage technology, owing to cost-effectiveness and enhanced safety. Among solid electrolytes for solid-state sodium batteries, NASICON-structured Na3Zr2Si2PO12 has emerged as a predominant candidate. However, its widespread implementation remains limited by suboptimal ionic conductivity in both bulk and grain boundary regions. In this study, we demonstrate a novel approach utilizing swirling spray flame synthesis to produce Mg-doped NASICON solid electrolyte nanoparticles. This method facilitates efficient doping and homogeneous mixing for scalable production, resulting in core-shell non-NASICON structures with nano-scale high-entropy mixing. Notably, the atomic migration distances achieved by flame synthesis are significantly reduced compared to conventional solid-state reactions, thereby enabling reactive sintering to preserve high sinterability of nanoparticles during post-treatment processes. High-temperature sintering yields dense NASICON-structured solid electrolytes. Among those, Mg0.25NZSP exhibits an optimal ionic conductivity of 1.91 mS/cm at room temperature and an activation energy of 0.200 eV. The enhancement mechanism can be attributed to incorporation into the NASICON phase and formation of a secondary phase. The low-melting-point secondary phase significantly improves grain boundary contact to enhance grain boundary conductivity. The process achieves simultaneous enhancement of both bulk and grain boundary conduction through a single-step procedure. Comparative analysis of sintering temperatures and ionic conductivities among NASICON solid electrolytes synthesized via different methods demonstrates flame-synthesized nanoparticles offer superior performance and reduced post-treatment costs, owing to their exceptional nano-scale sinterability and uniform elemental distribution.

cond-mat.mtrl-sci↗

arXiv2025

Spray flame synthesis of Y2O3-MgO nanoparticles for mid-infrared transparent nanocomposite ceramics

Spray flame synthesis offers a promising method for scalable production of homogeneously mixed Y2O3-MgO nanopowders as next-generation infrared-transparent window material, which has attracted significant attention owing to its excellent optical properties at high temperatures. However, systematic understanding of how flame synthesis parameters influence particle morphology, crystal phase, solid solubility, and subsequent ceramic performance remains insufficiently understood. In this study, we investigated the influence of precursor chemistry on particle crystal phase and examined the solid solubility of MgO in Y2O3 under different flame temperatures, demonstrating that the high-temperature conditions with O2 as dispersion gas allow up to 50 mol% MgO to fully dissolve into Y2O3, far exceeding the equilibrium solubility limit of 7 mol% at the eutectic temperature (2100{\deg}C) and near-zero at room temperature. Furthermore, we systematically evaluated how powder characteristics and sintering parameters-including powder deagglomeration methods, vacuum sintering temperature, hot isostatic pressing (HIP) temperature, and initial powder characteristics-affect ceramic microstructures and infrared transmittance. Despite cracking induced by phase transformation and finer particle sizes, ceramics fabricated from oxygen-synthesized monoclinic-dominated powders exhibited superior near-infrared transmittance (56.2% at 1550 nm), attributed to enhanced atomic mixing and effective grain boundary pinning. After optimization, pure cubic phase powders produced intact and crack-free ceramics with outstanding mid-infrared transparency, achieving a maximum transmittance of 84.6% and an average transmittance of 82.3% in 3-5 um range.

cond-mat.mtrl-sci↗

arXiv2024

Turbulence-induced oscillation on particle detachment from a wall

Particle resuspension is a ubiquitous phenomenon with pivotal relevance in numerous natural and industrial contexts. In this study, we present findings on the resuspension of individual micro-sized particles, captured through high-speed camera experiments. Our observations reveal a universal behavior whereby a particle undergoes oscillatory motion due to turbulent excitation prior to its detachment from the surface. This motion is characterized by dimensionless number Ad and S. The frequency of particles oscillation is analyzed and it shows the frequency of particle oscillations increased with decreasing particle size. We establish a new model that the particle is a linear oscillator driven by stochastic torque from turbulence. It is shown that the stochastic oscillation is the key mechanism for particle detachment from a wall within a certain range of friction velocities.

physics.flu-dyn↗

arXiv2020

Collision-induced breakage of agglomerates in homogenous isotropic turbulence laden with adhesive particles

We carry out direct numerical simulation combined with adhesive discrete element calculations to investigate collision-induced breakage of agglomerates in homogeneous isotropic turbulence. Based on extensive simulation runs, an adhesion parameter Adn is constructed to quantify the possibility of occurrence of sticking, rebound, and breakage events. The collision-induced breakage rate is then formulated based on the Smoluchowski equation and a breakage fraction. The breakage fraction, defined as the fraction of collisions that result in breakage, is then analytically estimated by a convolution of the probability distribution of collision velocity and a universal transfer function. It is shown that the breakage rate decreases exponentially as the adhesion parameter Adn increases for doublets and scales as linear functions of the agglomerate size, with the slope controlled by Adn. These results allow one to estimate the breakage rate for early-stage agglomerates of arbitrary size. Moreover, the role of the flow structure on the collision-induced breakage is also examined. Violent collisions and breakages are more likely caused by particles ejected rapidly from strong vortices and happen in straining sheets. Our results extend the findings of shear-induced fragmentation, forming a more complete picture of breakage of agglomerates in turbulent flows.

physics.flu-dyn↗

arXiv2018

Exponential Scaling in Early-stage Agglomeration of Adhesive Particles in Turbulence

We carry out direct numerical simulation together with an adhesive discrete element method calculation (DNS-DEM) to investigate agglomeration of particles in homogeneous isotropic turbulence (HIT). We report an exponential-form scaling for the size distribution of early-stage agglomerates, which is valid across a wide range of particle inertia and inter-particle adhesion values. Such scaling allows one to quantify the state of agglomeration using a single scale parameter. An agglomeration kernel is then constructed containing the information of agglomerate structures and the sticking probability. An explicit relationship between the sticking probability and microscale particle properties is also proposed based on the scaling analysis of the equation for head-on collisions. Our results extend Smoluchowski's theory to the condition of non-coalescing solid adhesive particles and can reproduce DNS-DEM results with a simple one-dimensional simulation.

physics.flu-dyn↗

arXiv2018

Stability Analysis of Quadrature-based Moment Methods for Kinetic Equations

In this paper, we present a systematic stability analysis of the quadrature-based moment method (QBMM) for the one-dimensional Boltzmann equation with BGK or Shakhov models. As reported in recent literature, the method has revealed its potential for modeling non-equilibrium flows, while a thorough theoretical analysis is largely missing but desirable. We show that the method can yield non-hyperbolic moment systems if the distribution function is approximated by a linear combination of $\delta$-functions. On the other hand, if the $\delta$-functions are replaced by their Gaussian approximations with a common variance, we prove that the moment systems are strictly hyperbolic and preserve the dissipation property (or $H$-theorem) of the kinetic equation. In the proof we also determine the equilibrium manifold that lies on the boundary of the state space. The proofs are quite technical and involve detailed analyses of the characteristic polynomials of the coefficient matrices.

math.NA↗

arXiv2018

Unifying size-topology relations in random packings of dry adhesive polydisperse spheres

We study the size-topology relations in random packings of dry adhesive polydisperse microspheres with Gaussian and lognormal size distributions through a geometric tessellation. We find that the dependence of the neighbour number on the centric particle size is always quasilinear, independent of the size distribution, the size span or interparticle adhesion. The average local packing fraction as a function of normalized particle size for different size variances is well regressed on the same profile, which grows to larger values as the relative strength of adhesion decreases. As for the local coordination number-particle size profiles, they converge onto a single curve for all the adhesive particles, but will gradually transfer to another branch for non-adhesive particles. Such adhesion induced size-topology relations are interpreted theoretically by a modified geometrical "granocentric" model, where the model parameters are dependent on a dimensionless adhesion number. Our findings, together with the modified theory, provide a more unified perspective on the substantial geometry of amorphous polydisperse systems, especially those with fairly loose structures.

cond-mat.soft↗

arXiv2018

A fast adhesive discrete element method for random packings of fine particles

Introducing a reduced particle stiffness in discrete element method (DEM) allows for bigger time steps and therefore fewer total iterations in a simulation. Although this approach works well for dry non-adhesive particles, it has been shown that for fine particles with adhesion, system behaviors are drastically sensitive to the particle stiffness. Besides, a simple and applicable principle to set the parameters in adhesive DEM is also lacking. To solve these two problems, we first propose a fast DEM based on scaling laws to reduce particle Young's modulus, surface energy and to modify rolling and sliding resistances simultaneously in the framework of Johnson-Kendall-Roberts (JKR)-based contact theory. A novel inversion method is then presented to help users to quickly determine the damping coefficient, particle stiffness and surface energy to reproduce a prescribed experimental result. After validating this inversion method, we apply the fast adhesive DEM to packing problems of microparticles. Measures of packing fraction, averaged coordination number and distributions of local packing fraction and contact number of each particle are in good agreement with results simulated using original value of particle properties. The new method should be helpful to accelerate DEM simulations for systems associated with aggregates or agglomerates.

cond-mat.soft↗

arXiv2017

High-resolution of particle contacts via fluorophore exclusion in deep-imaging of jammed colloidal packings

Understanding the structural properties of random packings of jammed colloids requires an unprecedented high-resolution determination of the contact network providing mechanical stability to the packing. Here, we address the determination of the contact network by a novel strategy based on fluorophore signal exclusion of quantum dot nanoparticles from the contact points. We use fluorescence labeling schemes on particles inspired by biology and biointerface science in conjunction with fluorophore exclusion at the contact region. The method provides high-resolution contact network data that allows us to measure structural properties of the colloidal packing near marginal stability. We determine scaling laws of force distributions, soft modes, correlation functions, coordination number and free volume that define the universality class of jammed colloidal packings and can be compared with theoretical predictions. The contact detection method opens up further experimental testing at the interface of jamming and glass physics.

cond-mat.soft↗

arXiv2017

Equation of state for random sphere packing with arbitrary adhesion and friction

We systematically generate a large set of random micro-particle packings over a wide range of adhesion and friction by means of adhesive contact dynamics simulation. The ensemble of generated packings covers a range of volume fraction $ϕ$ from $0.135 \pm 0.007$ to $0.639 \pm 0.004$, and of coordination number $Z$ from $2.11 \pm 0.03$ to $6.40 \pm 0.06$. We determine $ϕ$ and $Z$ at four limits (random close packing, random loose packing, adhesive close packing, and adhesive loose packing), and find a universal equation of state $ϕ(Z)$ to describe packings with arbitrary adhesion and friction. From a mechanical equilibrium analysis, we determine a critical friction coefficient $μ_{\rm f, c}$: when the friction coefficient $μ_{\rm f}$ is below $μ_{\rm f, c}$, particles' rearrangements are dominated by sliding, otherwise, they are dominated by rolling. Because of this reason, both $ϕ(μ_{\rm f})$ and $Z(μ_{\rm f})$ change sharply across $μ_{\rm f, c}$. Finally, we generalize the Maxwell counting argument to micro-particle packings, and show that the loosest packing, i.e., adhesive loose packing, satisfies the isostatic condition at $Z=2$.

cond-mat.soft↗

arXiv2015

Computer simulation of random loose packings of micro-particles in presence of adhesion and friction

With a novel 3D discrete-element method specially developed with adhesive contact mechanics, random loose packings of uniform spherical micron-sized particles are fully investigated. The results show that large velocity, large size or weak adhesion can produce a relatively dense packing when other parameters are fixed, and these combined effects can be characterized by a dimensionless adhesion parameter ( $Ad=ω/2ρ_pU^2_0R$). Four regimes are identified based on the value of $Ad$: RCP regime with $Ad<\sim 0.01$; RLP regime with $\sim 0.01 20$. Force distribution of these adhesive loose packings follows $P(f)\sim f^θ$ for small forces and $P(f)\sim \exp^{-βf}$ for big forces, respectively, which shares a similar form with that in packings without adhesion but results in distinct exponents of $θ=0.879$, $β=0.839$. A local mechanical equilibrium analysis shows that adhesion enhances both sliding and rolling resistance so that fewer neighbours are needed to satisfy the force and torque balance.

cond-mat.soft↗

arXiv2015

Effect of long-range repulsive Coulomb interactions on packing structure of adhesive particles

The packing of charged micron-sized particles was investigated using discrete element simulations based on adhesive contact dynamic model. The formation process and the final obtained structures of ballistic packings are studied to show the effect of interparticle Coulomb force. It was found that increasing the charge on particles causes a remarkable decrease of the packing volume fraction ϕand the average coordination number Z, indicating a looser and chainlike structure. Force-scaling analysis shows that the long-range Coulomb interaction changes packing structures through its influence on particle inertia before they are bonded into the force networks. Once contact networks are formed, the expansion effect caused by repulsive Coulomb forces are dominated by short-range adhesion. Based on abundant results from simulations, a dimensionless adhesion parameter Ad* , which combines the effects of the particle inertia, the short-range adhesion and the long-range Coulomb interaction, is proposed and successfully scales the packing results for micron-sized particles within the latestly derived adhesive loose packing (ALP) regime. The structural properties of our packings follow well the recent theoretical prediction which is described by an ensemble approach based on a coarse-grained volume function, indicating some kind of universality in the low packing density regime of the phase diagram regardless of adhesion or particle charge. Based on the comprehensive consideration of the complicated inter-particle interactions, our findings provide insight into the roles of short-range adhesion and repulsive Coulomb force during packing formation and should be useful for further design of packings.

cond-mat.soft↗

arXiv2014

Absorption-Ablation-Excitation Mechanisms of Laser-Cluster Interactions in a Nanoaerosol System

The absorption-ablation-excitation mechanism in laser-cluster interactions is investigated by measuring Rayleigh scattering of aerosol clusters along with atomic emission from phase-selective laser-induced breakdown spectroscopy (PS-LIBS). As the excitation laser intensity is increased beyond 0.16GW/cm2, the scattering cross-section of TiO_2 clusters begins to decrease, concurrent with the onset of atomic emission of Ti, indicating a scattering-to-ablation transition and the formation of nanoplasmas. To better clarify the process, time-resolved measurements of scattering signals are examined for different excitation laser intensities. For increasing laser intensities, the cross-sections of clusters decrease during a single pulse, evincing the shorter ablation delay time and larger ratios of ablation clusters. Assessment of the electron energy distribution during the ablation process is conducted by non-dimensionalizing the Fokker-Planck equation, with analogous Strouhal Sl_E, Peclet Pe_E, and Damkohler Da_E numbers defined to characterize the laser-induced aerothermochemical environment. For conditions of Sl_E>>1, Pe_E>>1, and Da_E<<1, the electrons are excited to the conduction band by two-photon absorption, then relax to bottom of the conduction band by collisional electron energy loss to the lattice, and finally serve as the energy transfer media between laser field and lattice. The relation between delay time and excitation intensity is well predicted by this simplified model with quasi-steady assumption.

physics.atm-clus↗

arXiv2014

Adhesive Loose Packings of Small Particles

We explore adhesive loose packings of dry small spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics. A dimensionless adhesion parameter ($Ad$) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for $Ad>1$. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes correlations between bulk and contact spheres. Our theoretical and numerical results predict: (i) An equation of state for adhesive loose packings that appears as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram; (ii) The existence of a maximal loose packing point at the coordination number $Z=2$ and packing fraction $ϕ=1/2^{3}$. Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing, which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

cond-mat.soft↗