arXiv subjects

Xiao Wan

Publications and source records attributed to Xiao Wan.

13 recordsLinked to original sources

arXiv2026

A Novel Bijective Angle and Volume-preservation Balanced Parameterization for $n$-dimensional Manifolds

We propose a unified framework for balanced and bijective parameterizations of $n$-dimensional manifolds. The proposed energy combines conformal and volume-preserving terms to control both local anisotropy and volumetric distortion. At the continuous level, both energies are nonnegative and their zero-energy mappings are characterized. At the discrete level, the conformal, volume-preserving, and logarithmic barrier energies are formulated on oriented simplicial manifolds. A key result is that all their gradients admit a unified cotangent Laplacian-type representation, enabling sparse and dimension-independent computation. Bijectivity is enforced through signed simplex Jacobians, feasibility restoration, and a strictly orientation-preserving logarithmic barrier. The framework applies uniformly to spherical boundary parameterizations and parameterizations of discrete $n$-manifolds onto ball-like canonical domains.

math.NA↗

arXiv2024

Deep potential for interaction between hydrated Cs+ and graphene

The influence of hydrated cation-{\pi} interaction forces on the adsorption and filtration capabilities of graphene-based membrane materials is significant. However, the lack of interaction potential between hydrated Cs+ and graphene limits the scope of adsorption studies. Here, it is developed that a deep neural network potential function model to predict the interaction force between hydrated Cs+ and graphene. The deep potential has DFT-level accuracy, enabling accurate property prediction. This deep potential is employed to investigate the properties of the graphene surface solution, including the density distribution, mean square displacement, and vibrational power spectrum of water. Furthermore, calculations of the molecular orbital electron distributions indicate the presence of electron migration in the molecular orbitals of graphene and hydrated Cs+, resulting in a strong electrostatic interaction force. The method provides a powerful tool to study the adsorption behavior of hydrated cations on graphene surfaces and offers a new solution for handling radionuclides.

physics.comp-ph↗

arXiv2023

Using Targeted Phonon Excitation to Modulate Thermal Conductivity of Boron Nitride

Recent advancements in thermal conductivity modulating strategies have shown promising enhancements to the thermal management capabilities of two-dimensional materials. In this article, both iterative Boltzmann transport equation solution and two-temperature model were employed to investigate the efficacy of targeted phonon excitation applied to hexagonal boron nitride. The results indicate significant modifications to hBN's thermal conductivity, achieving increases of up to 30.1% as well as decreases of up to 59.8%. These findings validate the reliability of the strategy, expand its scope of applicability, and establish it as a powerful tool for tailoring thermal properties across a wider range of fields.

cond-mat.mtrl-sci↗

arXiv2023

Enhancing interfacial thermal conductance of Si/PVDF by strengthening atomic couplings

The thermal transport across inorganic/organic interfaces attracts interest for both academic and industry due to its widely applications in flexible electronics etc. Here, the interfacial thermal conductance of inorganic/organic interfaces consisting of silicon and polyvinylidene fluoride is systematically investigated by molecular dynamics simulations. Interestingly, it is demonstrated that a modified silicon surface with hydroxyl groups can drastically enhance the conductance by 698%. These results are elucidated based on interfacial couplings and lattice dynamics insights. This study not only provides feasible strategies to effectively modulate the interfacial thermal conductance of inorganic/organic interfaces but also deepens the understanding of the fundamental physics underlying phonon transport across interfaces.

cond-mat.mtrl-sci↗

arXiv2022

Modulating Thermal Conductivity via Targeted Phonon Excitation

Thermal conductivity is a critical material property in numerous applications, such as those related to thermoelectric devices and heat dissipation. Effectively modulating thermal conductivity has become a great concern in the field of heat conduction. In this study, a quantum strategy is proposed to modulate thermal conductivity by exciting targeted phonons. The results show that the thermal conductivity of graphene can be tailored in the range of 1559 W/m-K (49%) to 4093 W/m-K (128%), compared with the intrinsic value of 3189 W/m-K. A similar trend is also observed for graphene nanoribbons. The results are obtained through both ab initio calculations and molecular dynamics simulations. This brand-new quantum strategy to modulate thermal conductivity paves a way for quantum heat conduction.

cond-mat.mtrl-sci↗

arXiv2021

Violation of Fourier's law in homogeneous systems

Hotspot is a ubiquitous phenomenon in microdevices/chips. In homogeneous nanoscale graphene disk with a hotspot, a graded thermal conductivity is observed previously even when the system size is fixed. However, the underlying physical mechanism is not clear. In this work, the hotspots in homogeneous 2D disk/3D ball and graphene disk are studied based on phonon Boltzmann transport equation. The mechanisms of phonon scattering are analyzed. It is found that for a system with fixed size, the graded thermal conductivity is predictable as long as there is not sufficient phonon scattering, which is independent on material properties, dimensions or system size. This work may shed light on both theoretical and experimental studies on heat dissipation of microelectronics.

cond-mat.mes-hall↗

arXiv2021

Thermal Conductivities and Mechanical Properties of Epoxy Resin as a Function of the Degree of Cross-linking

Epoxy resins are widely used polymer matrices for numerous applications. Despite substantial advances, the molecular-level knowledge-base required to exploit these materials to their full potential remains limited. A deeper comprehension of structure/property relationships in epoxy resins at the molecular level is critical to progressing these efforts. It can be laborious, if not impractical, to elucidate these relationships based on experiments alone. Here, molecular dynamics simulations are used to calculate and compare thermal conductivities and mechanical properties of an exemplar epoxy resin, Bisphenol F cross-linked with Diethyl Toluene Diamine, revealing these inter-relationships. Both elastic modulus and thermal transport of the epoxy resin show an increase with greater cross-linking. Specifically, decomposition of the thermal conductivity into different force contributions suggests that the bonded term contributes to an increase in the heat flux. These outcomes provide a foundation for designing and fabricating customized epoxy resins with desirable thermal and mechanical attributes.

cond-mat.mtrl-sci↗

arXiv2021

Optimizing Thermal Transport in Graphene Nanoribbon Based on Phonon Resonance Hybridization

As a critical way to modulate thermal transport in nanostructures, phonon resonance hybridization has become an issue of great concern in the field of phonon engineering. In this work, we optimized phonon transport across graphene nanoribbon and obtained minimized thermal conductance by means of designing pillared nanostructures based on resonance hybridization. Specifically, the optimization of thermal conductance was performed by the combination of atomic Green` s function and Bayesian optimization. Interestingly, it is found that thermal conductance decreases non-monotonically with the increasing of number for pillared structure, which is severed as resonator and blocks phonon transport. Further mode-analysis and atomic Green` s function calculations revealed that the anomalous tendency originates from decreased phonon transmission in a wide frequency range. Additionally, nonequilibrium molecular dynamics simulations are performed to verify the results with the consideration of high-order phonon scattering. This finding provides novel insights into the control of phonon transport in nanostructures.

cond-mat.mes-hall↗

arXiv2020

Maximization and Minimization of Interfacial Thermal Conductance by Modulating the Mass Distribution of Interlayer

Tuning interfacial thermal conductance has been a key task for the thermal management of nanoelectronic devices. Here, it is studied how the interfacial thermal conductance is great influenced by modulating the mass distribution of the interlayer of one-dimensional atomic chain. By nonequilibrium Green's function and machine learning algorithm, the maximum/minimum value of thermal conductance and its corresponding mass distribution are calculated. Interestingly, the mass distribution corresponding to the maximum thermal conductance is not a simple function, such as linear and exponential distribution predicted in previous works, it is similar to a sinusoidal curve around linear distribution for larger thickness interlayer. Further, the mechanism of the abnormal results is explained by analyzing the phonon transmission spectra and density of states. The work provides deep insight into optimizing and designing interfacial thermal conductance by modulating mass distribution of interlayer atoms.

cond-mat.mtrl-sci↗

arXiv2019

Materials discovery and properties prediction in thermal transport via materials informatics: a mini-review

There has been an increasing demand for materials with special thermal properties, whereas experimental discovery is high-cost and time-consuming. The emerging discipline `Materials Informatics' is an effective approach that can accelerate materials development by combining material science and big data technique. Recently materials informatics has been applied to the design of novel materials such as thermal interface materials for heat-dissipation, and thermoelectric materials for power generation. This mini-review summarized the research progress on the applications of materials informatics for the thermal transport properties prediction and discovery of materials with special thermal properties, including optimal thermal conductivity, interfacial thermal conductance and thermoelectricity efficiency. In addition, some perspectives are given for the outlook of materials informatics in the field of thermal transport.

cond-mat.mtrl-sci↗

arXiv2018

Unexpected Thermal Conductivity Enhancement in Pillared Graphene Nanoribbon with Isotopic Resonance

Thermal transport in nanoribbon based nanostructures is critical to advancing its applications. Wave effects of phonons can give rise to controllability of heat conduction in nanostructures beyond that by particle scattering. In this paper, by introducing pillars to form structural resonance, we systematically studied the thermal conductivity of graphene nanoribbon based phononic metamaterials (GNPM) through non-equilibrium molecular dynamical simulation. Interestingly, it is found that the thermal conductivity of GNPM is counter intuitively enhanced by isotope engineering, which is strong contrast to the common notion that isotope engineering reduces thermal conductivity.Further mode analysis and atomic Green function calculation reveal that the unexpected increasing in thermal conductivity originates from the breaking of the resonant hybridization wave effect between the resonant modes and the propagating modes induced by isotope engineering. Besides, factors including the system width and pillar height can also efficiently tune the thermal conductivity of GNPM. This abnormal mechanism provides a new dimension to manipulate phonon transport in nanoribbon based nanostructures through wave effect.

cond-mat.mes-hall↗

arXiv2017

Interfacial Thermal Transport in Boron Nitride-Polymer Nanocomposite

Polymer composites with thermally conductive nanoscale filler particles, such as graphene and hexagonal boron nitride (h-BN), are promising for certain heat transfer applications. While graphene-polymer composites have been extensively investigated, studies on h-BN-polymer composites has been relatively rare. In this paper, we use molecular dynamics (MD) simulations to study the interfacial thermal conductance (ITC) involved in the h-BN-polymer composites. We first compare the ITC across h-BN/hexane (C6H14) interfaces to that of graphene/hexane interfaces, where we found that the electrostatic interaction due to the partial charge on h-BN atoms can play an important role in such interfacial thermal transport. Based this finding, we further explore the thermal transport across different h-BN interfaces, including h-BN/hexanamine (C6H13NH2), h-BN/hexanol (C6H13OH), h-BN/hexanoic acid (C5H11COOH), where the increasingly polar molecules lead to systematic changes in the electrostatic interactions between h-BN and polymers. Heat flux decomposition and atom number density calculations are performed to understand the role of electrostatic interaction in thermal transport across h-BN-polymer interfaces. It was observed that stronger electrostatic interactions across the interfaces can help attract the polymer molecules closer to h-BN, and the reduced interface distance leads to larger heat flux contributed from both van der Waals and electrostatic forces. These results may provide useful information to guide the design of thermally conductive h-BN-polymer nanocomposites.

physics.app-ph↗

arXiv2016

Enhancing thermal conductivity of bulk polyethylene along two directions by paved crosswise laminate

Recently, some reports show that the ultra-low thermal conductivity of bulk polymers can be enhanced along one direction, which limits its applications. Here, we proposed paved crosswise laminate methods which can enhance the thermal conductivity of bulk polyethylene (PE) along two directions. We find that the thermal conductivity of paved crosswise polyethylene laminate (PPEL) reaches as high as 181 W/m-K along two in-plane directions, which is three orders of magnitude larger than bulk amorphous polyethylene and even more than two times larger than PE single chain (54 W/m-K). The analyses of mechanism indicated that PPEL is a much more crystal-like structure due to the inter-chain van der Waals interactions. Our study may provide guides on the design and fabrication of polymer structures with high thermal conductivity.

cond-mat.mtrl-sci↗