In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination,...In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination, it fails to capture the temporal dynamics of these systems and the effects of virus invasion and governmental regulation. Triadic percolation theory, a recent advancement, addresses these limitations. In this paper, we apply this new percolation mechanism to model the diffusion of computer viruses, deriving a precise mathematical formulation of the triadic percolation model and providing an analytical solution of the triadic percolation threshold. Additionally, we investigate the impact of nonlinear transmission probability characteristics on virus propagation. Numerical simulations demonstrate that reducing the network's average degree(or the positive regulation) or increasing regulatory interventions raises the outbreak threshold for computer viruses while decreasing their final size. Moreover, the study reveals that nonlinear transmission probabilities result in an increased number of solutions for the final size of the computer viruses. Our findings contribute new insights into controlling the spread of computer viruses.展开更多
Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocrit...Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocritical point.Focusing on two-dimensional percolation,we show that the size distribution of the largest cluster asymptotically approaches to a Gumbel form in the subcritical phase,a Gaussian form in the supercritical phase,and transitions within the critical finite-size scaling window.Numerical results indicate that,at consistently defined pseudocritical points,this distribution exhibits a universal form across various lattices and percolation models(bond or site),within error bars,yet differs from the distribution at the critical point.The critical polynomial,universally zero for two-dimensional percolation at the critical point,becomes nonzero at pseudocritical points.Nevertheless,numerical evidence suggests that the critical polynomial,along with other dimensionless quantities such as wrapping probabilities and Binder cumulants,assumes fixed values at the pseudocritical point that are independent of the percolation type(bond or site)but vary with lattice structures.These findings imply that while strict universality breaks down at the pseudocritical point,certain extreme-value statistics and dimensionless quantities exhibit quasi-universality,revealing a subtle connection between scaling behaviors at critical and pseudocritical points.展开更多
To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs l...To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.展开更多
Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks ...Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.展开更多
Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investig...Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investigate non-equilibrium phase transitions,specifically focusing on the directed percolation process.By converting lattices with varying dimensions and connectivity schemes into graph structures and embedding the temporal evolution of the percolation process into node features,our approach enables unified analysis across diverse systems.The framework utilizes a multi-layer graph attention mechanism combined with global pooling to autonomously extract critical features from local dynamics to global phase transition signatures.The model successfully predicts percolation thresholds without relying on lattice geometry,demonstrating its robustness and versatility.Our approach not only offers new insights into phase transition studies but also provides a powerful tool for analyzing complex dynamical systems across various domains.展开更多
Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl...Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.展开更多
In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applic...In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.展开更多
A noise reduction method for infrared detector output signal is studied during dynamic calibration of thermocou- pie. Firstly, the deficiency of the classical filter method is analyzed and the application of the wavel...A noise reduction method for infrared detector output signal is studied during dynamic calibration of thermocou- pie. Firstly, the deficiency of the classical filter method is analyzed and the application of the wavelet analysis is introduced for signal de-noising during the dynamic testing. Secondly, the theoretical basis of wavelet analysis, the choice of wavelet base and the determination of decomposed series and threshold are analyzed. Finally, the de-noising experiment for infrared detector signal is carried out on the Matlab platform. The results indicate the proposed wavelet de-noising method is effective to remove fixed frequency and high-frequency noise; furthermore, good synchronization is achieved between the de-noised signal and the useful signal components in the original signal, which is of great significance to thermocouple modeling analys- is.展开更多
The air transportation system has a critical impact on the global economy.While the system reliability is essential for the operational management of air traffic,it remains challenging to understand the network reliab...The air transportation system has a critical impact on the global economy.While the system reliability is essential for the operational management of air traffic,it remains challenging to understand the network reliability of the air transportation system.This paper focuses on how the global air traffic is integrated from local scale along with operational time.The integration process of air traffic into a temporally connected network is viewed as percolation process by increasing the integration time constantly.The critical integration time TPwhich is found during the integration process can measure the global reliability of air traffic.The critical links at TPare also identified,the delay of which will influence the global integration of the airport network.These findings may provide insights on the reliability management for the temporal airport network.展开更多
As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the conn...As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the connection of the networked system, the concept of dependence link is proposed to represent the dependence relationship of agents. These studies suggest that the percolation properties of these networks differ greatly from those of the ordinary networks. In particular, unlike the well known continuous transition on the ordinary networks, the percolation transitions on these networks are discontinuous. Moreover, these networks are more fragile for a broader degree distribution, which is opposite to the famous results for the ordinary networks. In this article, we give a summary of the theoretical approaches to study the percolation process on networks with inter- and inner-dependence links, and review the recent advances in this field, focusing on the topology and robustness of such networks.展开更多
For bottom water reservoir and the reservoir with a thick oil formation, there exists partial penetration completion well and when the well products the oil flow in the porous media takes on spherical percolation. The...For bottom water reservoir and the reservoir with a thick oil formation, there exists partial penetration completion well and when the well products the oil flow in the porous media takes on spherical percolation. The nonlinear spheri-cal flow equation with the quadratic gradient term is deduced in detail based on the mass conservation principle, and then it is found that the linear percolation is the approximation and simplification of nonlinear percolation. The nonlinear spherical percolation physical and mathematical model under different external boundaries is established, considering the ef-fect of wellbore storage. By variable substitu-tion, the flow equation is linearized, then the Laplace space analytic solution under different external boundaries is obtained and the real space solution is also gotten by use of the nu-merical inversion, so the pressure and the pressure derivative bi-logarithmic nonlinear spherical percolation type curves are drawn up at last. The characteristics of the nonlinear spherical percolation are analyzed, and it is found that the new nonlinear percolation type curves are evidently different from linear per-colation type curves in shape and characteris-tics, the pressure curve and pressure derivative curve of nonlinear percolation deviate from those of linear percolation. The theoretical off-set of the pressure and the pressure derivative between the linear and the nonlinear solution are analyzed, and it is also found that the in-fluence of the quadratic pressure gradient is very distinct, especially for the low permeabil-ity and heavy oil reservoirs. The influence of the non-linear term upon the spreading of pressure is very distinct on the process of percolation, and the nonlinear percolation law stands for the actual oil percolation law in res-ervoir, therefore the research on nonlinear per-colation theory should be strengthened and reinforced.展开更多
An implicit finite difference method is developed for a one-dimensional frac- tional percolation equation （FPE） with the Dirichlet and fractional boundary conditions. The stability and convergence are discussed for ...An implicit finite difference method is developed for a one-dimensional frac- tional percolation equation （FPE） with the Dirichlet and fractional boundary conditions. The stability and convergence are discussed for two special cases, i.e., a continued seep- age flow with a monotone percolation coefficient and a seepage flow with the fractional Neumann boundary condition. The accuracy and efficiency of the method are checked with two numerical examples.展开更多
Using numerical simulation data of the forward differential propagation shift （ΦDP） of polarimetric radar,the principle and performing steps of noise reduction by wavelet analysis are introduced in detail.Profiting...Using numerical simulation data of the forward differential propagation shift （ΦDP） of polarimetric radar,the principle and performing steps of noise reduction by wavelet analysis are introduced in detail.Profiting from the multiscale analysis,various types of noises can be identified according to their characteristics in different scales,and suppressed in different resolutions by a penalty threshold strategy through which a fixed threshold value is applied,a default threshold strategy through which the threshold value is determined by the noise intensity,or a ΦDP penalty threshold strategy through which a special value is designed for ΦDP de-noising.Then,a hard-or soft-threshold function,depending on the de-noising purpose,is selected to reconstruct the signal.Combining the three noise suppression strategies and the two signal reconstruction functions,and without loss of generality,two schemes are presented to verify the de-noising effect by dbN wavelets：（1） the penalty threshold strategy with the soft threshold function scheme （PSS）; （2） the ΦDP penalty threshold strategy with the soft threshold function scheme （PPSS）.Furthermore,the wavelet de-noising is compared with the mean,median,Kalman,and finite impulse response （FIR） methods with simulation data and two actual cases.The results suggest that both of the two schemes perform well,especially when ΦDP data are simultaneously polluted by various scales and types of noises.A slight difference is that the PSS method can retain more detail,and the PPSS can smooth the signal more successfully.展开更多
The network dismantling problem asks the minimum separate node set of a graph whose removal will break the graph into connected components with the size not larger than the one percentage of the original graph.This pr...The network dismantling problem asks the minimum separate node set of a graph whose removal will break the graph into connected components with the size not larger than the one percentage of the original graph.This problem has attracted much attention recently and a lot of algorithms have been proposed. However, most of the network dismantling algorithms mainly focus on which nodes are included in the minimum separate set but overlook how to order them for removal, which will lead to low general efficiency during the dismantling process. In this paper,we reformulate the network dismantling problem by taking the order of nodes’ removal into consideration. An efficient dismantling sequence will break the network quickly during the dismantling processes. We take the belief-propagation guided decimation(BPD) dismantling algorithm, a state-of-the-art algorithm, as an example, and employ the node explosive percolation(NEP) algorithm to reorder the early part of the dismantling sequence given by the BPD. The proposed method is denoted as the NEP-BPD algorithm(NBA) here. The numerical results on Erd¨os-R′enyi graphs,random-regular graphs, scale-free graphs, and some real networks show the high general efficiency of NBA during the entire dismantling process. In addition, numerical computations on random graph ensembles with the size from 210 to219 exhibit that the NBA is in the same complexity class with the BPD algorithm. It is clear that the NEP method we used to improve the general efficiency could also be applied to other dismantling algorithms, such as Min-Sum algorithm,equal graph partitioning algorithm and so on.展开更多
The addition of graphite powder in conventional asphalt mixture can produced asp halt concrete with excellent electrical performance. Percolation theor y was employed to discuss the relation between the conductivity a...The addition of graphite powder in conventional asphalt mixture can produced asp halt concrete with excellent electrical performance. Percolation theor y was employed to discuss the relation between the conductivity and graphite con tent of graphite-modified asphalt concrete. It was found that the results of pe rcolation model are consistent with experimental values. The percolation thresho ld of graphite-modified asphalt concrete is 10.94% graphite content account for the total volume of the binder phase consisting of asphalt and graphite. The cr itical exponent is 3.16, beyond the range of 1.6-2.1 for the standard lattice c ontinuous percolation problem. Its reason is that the tunnel conduction mec hanism originates near the critical percent content, which causes this system to be not universal. Tunnel mechanism is demonstrated by the nonlinear voltage-cu rrent characteristic near percolation threshold.The percolation model is able to well predict the formation and development of conductive network in graphite- modified asphalt concrete.展开更多
A novel method for preparing conductive carbon black fllled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper. The experimental results indicate that with a rise i...A novel method for preparing conductive carbon black fllled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper. The experimental results indicate that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occurs at 0.8-1.4vol%. In contrast, the solution blended composites exhibit drastic increase in conductivity at conducting filler fraction as high as 12.3-13.3vol%. It is demonstrated that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites.展开更多
Gyro＇s drift is not only the main drift error which influences gyro＇s precision but also the primary factor that affects gyro＇s reliability. Reducing zero drift and random drift is a key problem to the output of a ...Gyro＇s drift is not only the main drift error which influences gyro＇s precision but also the primary factor that affects gyro＇s reliability. Reducing zero drift and random drift is a key problem to the output of a gyro signal. A three-layer de-nosing threshold algorithm is proposed based on the wavelet decomposition to dispose the signal which is collected from a running fiber optic gyro （FOG）. The coefficients are obtained from the three-layer wavelet packet decomposition. By setting the high frequency part which is greater than wavelet packet threshold as zero, then reconstructing the nodes which have been filtered out noise and interruption, the soft threshold function is constructed by the coefficients of the third nodes. Compared wavelet packet de-noise with forced de-noising method, the proposed method is more effective. Simulation results show that the random drift compensation is enhanced by 13.1%, and reduces zero drift by 0.052 6°/h.展开更多
The nonlinear effects of unsteady multi-scale shale gas percolation,such as desorption,slippage,diffusion,pressure-dependent viscosity,and compressibility,are investigated by numerical simulation.A new general mathema...The nonlinear effects of unsteady multi-scale shale gas percolation,such as desorption,slippage,diffusion,pressure-dependent viscosity,and compressibility,are investigated by numerical simulation.A new general mathematical model of the problem is built,in which the Gaussian distribution is used to describe the inhomogeneous intrinsic permeability.Based on the Boltzmann transformation,an efficient semi-analytical method is proposed.The problem is then converted into a nonlinear equation in an integral form for the pressure field,and a related explicit iteration scheme is constructed by numerical discretization.The validation examples show that the proposed method has good convergence,and the simulation results also agree well with the results obtained from both numerical and actual data of two vertical fractured test wells in the literature.Desorption,slippage,and diffusion have significant influence on shale gas flows.The accuracy of the usual technique that the product of viscosity and compressibility is approximated as its value at the average formation pressure is examined.展开更多
Making use of modern nonlinear physics theory and earthquake focus theory, combined with seismicity characteristics, the percolation model of earthquake activity is given in this paper. We take the seismogenic process...Making use of modern nonlinear physics theory and earthquake focus theory, combined with seismicity characteristics, the percolation model of earthquake activity is given in this paper. We take the seismogenic process of alarge earthquake as a phase transition process of percolation and apply the renormalization method to phase transition of percolation. The critical property of the system, which is like percolation probability exponential andcorrelative length exponential, etc, can be calculated under the fixed point as which in the renormalization transformation infinite correlative length in percolation phase transition is taken. The percolation phase transition process of two large earthquakes, which are Haicheng and Tangshan event occurred in 1975 and 1976 respectively, hasbeen discussed by means of seismicity data before and after two shocks.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12101573 and 12022113)the Fundamental Research Program of Shanxi Province,China (Grant Nos. 20210302124381,202203021211213,and 20210302123018)。
文摘In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination, it fails to capture the temporal dynamics of these systems and the effects of virus invasion and governmental regulation. Triadic percolation theory, a recent advancement, addresses these limitations. In this paper, we apply this new percolation mechanism to model the diffusion of computer viruses, deriving a precise mathematical formulation of the triadic percolation model and providing an analytical solution of the triadic percolation threshold. Additionally, we investigate the impact of nonlinear transmission probability characteristics on virus propagation. Numerical simulations demonstrate that reducing the network's average degree(or the positive regulation) or increasing regulatory interventions raises the outbreak threshold for computer viruses while decreasing their final size. Moreover, the study reveals that nonlinear transmission probabilities result in an increased number of solutions for the final size of the computer viruses. Our findings contribute new insights into controlling the spread of computer viruses.
基金supported by the National Natural Science Foundation of China(Grant No.12275263)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301900)Natural Science Foundation of Fujian Province of China(Grant No.2023J02032).
文摘Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocritical point.Focusing on two-dimensional percolation,we show that the size distribution of the largest cluster asymptotically approaches to a Gumbel form in the subcritical phase,a Gaussian form in the supercritical phase,and transitions within the critical finite-size scaling window.Numerical results indicate that,at consistently defined pseudocritical points,this distribution exhibits a universal form across various lattices and percolation models(bond or site),within error bars,yet differs from the distribution at the critical point.The critical polynomial,universally zero for two-dimensional percolation at the critical point,becomes nonzero at pseudocritical points.Nevertheless,numerical evidence suggests that the critical polynomial,along with other dimensionless quantities such as wrapping probabilities and Binder cumulants,assumes fixed values at the pseudocritical point that are independent of the percolation type(bond or site)but vary with lattice structures.These findings imply that while strict universality breaks down at the pseudocritical point,certain extreme-value statistics and dimensionless quantities exhibit quasi-universality,revealing a subtle connection between scaling behaviors at critical and pseudocritical points.
基金supported by National Natural Science Foundation of China(Grant No.42473017)Hong Kong RGC grants(JLFS/P-702/24 and 17308023)China Geological Survey project(Grant No.DD20242037).
文摘To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.
基金supported by the National Research Foundation of Korea(NRF)Grant(RS-2024-00343512,RS-2024-00416938).
文摘Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.
基金supported by the Fund from the Science and Technology Department of Henan Province,China(Grant Nos.222102210233 and 232102210064)the National Natural Science Foundation of China(Grant Nos.62373169 and 72474086)+5 种基金the Young and Midcareer Academic Leader of Jiangsu Province,China(Grant No.Qinglan Project in 2024)the National Statistical Science Research Project(Grant No.2022LZ03)Shaanxi Provincial Soft Science Project(Grant No.2022KRM111)Shaanxi Provincial Social Science Foundation(Grant No.2022R016)the Special Project for Philosophical and Social Sciences Research in Shaanxi Province,China(Grant No.2024QN018)the Fund from the Henan Office of Philosophy and Social Science(Grant No.2023CJJ112).
文摘Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investigate non-equilibrium phase transitions,specifically focusing on the directed percolation process.By converting lattices with varying dimensions and connectivity schemes into graph structures and embedding the temporal evolution of the percolation process into node features,our approach enables unified analysis across diverse systems.The framework utilizes a multi-layer graph attention mechanism combined with global pooling to autonomously extract critical features from local dynamics to global phase transition signatures.The model successfully predicts percolation thresholds without relying on lattice geometry,demonstrating its robustness and versatility.Our approach not only offers new insights into phase transition studies but also provides a powerful tool for analyzing complex dynamical systems across various domains.
基金Project supported by the National Natural Science Foundation of China(U2002215)。
文摘Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.
基金supported by the National Key R&D Program(Grant No.2022YFA1203-100)sponsorship by Shanghai Sailing Program(Grant No.24YF2713800)+2 种基金financial support from the Local College Capacity Building Project of Shanghai Municipal Science and Technology Commission(Grant No.20010500700)the Natural Science Foundation of Shanghai(Grant No.23ZR1424300)Shanghai Shuguang Program(Grant No.22SG56)。
文摘In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.
文摘A noise reduction method for infrared detector output signal is studied during dynamic calibration of thermocou- pie. Firstly, the deficiency of the classical filter method is analyzed and the application of the wavelet analysis is introduced for signal de-noising during the dynamic testing. Secondly, the theoretical basis of wavelet analysis, the choice of wavelet base and the determination of decomposed series and threshold are analyzed. Finally, the de-noising experiment for infrared detector signal is carried out on the Matlab platform. The results indicate the proposed wavelet de-noising method is effective to remove fixed frequency and high-frequency noise; furthermore, good synchronization is achieved between the de-noised signal and the useful signal components in the original signal, which is of great significance to thermocouple modeling analys- is.
基金support from the National Natural Science Foundation of China(Nos.71822101 and 71771009)the Fundamental Research Funds for the Central Universities.
文摘The air transportation system has a critical impact on the global economy.While the system reliability is essential for the operational management of air traffic,it remains challenging to understand the network reliability of the air transportation system.This paper focuses on how the global air traffic is integrated from local scale along with operational time.The integration process of air traffic into a temporally connected network is viewed as percolation process by increasing the integration time constantly.The critical integration time TPwhich is found during the integration process can measure the global reliability of air traffic.The critical links at TPare also identified,the delay of which will influence the global integration of the airport network.These findings may provide insights on the reliability management for the temporal airport network.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275186 and 91024026)
文摘As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the connection of the networked system, the concept of dependence link is proposed to represent the dependence relationship of agents. These studies suggest that the percolation properties of these networks differ greatly from those of the ordinary networks. In particular, unlike the well known continuous transition on the ordinary networks, the percolation transitions on these networks are discontinuous. Moreover, these networks are more fragile for a broader degree distribution, which is opposite to the famous results for the ordinary networks. In this article, we give a summary of the theoretical approaches to study the percolation process on networks with inter- and inner-dependence links, and review the recent advances in this field, focusing on the topology and robustness of such networks.
文摘For bottom water reservoir and the reservoir with a thick oil formation, there exists partial penetration completion well and when the well products the oil flow in the porous media takes on spherical percolation. The nonlinear spheri-cal flow equation with the quadratic gradient term is deduced in detail based on the mass conservation principle, and then it is found that the linear percolation is the approximation and simplification of nonlinear percolation. The nonlinear spherical percolation physical and mathematical model under different external boundaries is established, considering the ef-fect of wellbore storage. By variable substitu-tion, the flow equation is linearized, then the Laplace space analytic solution under different external boundaries is obtained and the real space solution is also gotten by use of the nu-merical inversion, so the pressure and the pressure derivative bi-logarithmic nonlinear spherical percolation type curves are drawn up at last. The characteristics of the nonlinear spherical percolation are analyzed, and it is found that the new nonlinear percolation type curves are evidently different from linear per-colation type curves in shape and characteris-tics, the pressure curve and pressure derivative curve of nonlinear percolation deviate from those of linear percolation. The theoretical off-set of the pressure and the pressure derivative between the linear and the nonlinear solution are analyzed, and it is also found that the in-fluence of the quadratic pressure gradient is very distinct, especially for the low permeabil-ity and heavy oil reservoirs. The influence of the non-linear term upon the spreading of pressure is very distinct on the process of percolation, and the nonlinear percolation law stands for the actual oil percolation law in res-ervoir, therefore the research on nonlinear per-colation theory should be strengthened and reinforced.
基金supported by the National Natural Science Foundation of China(Nos.11171193 and11371229)the Natural Science Foundation of Shandong Province(No.ZR2014AM033)the Science and Technology Development Project of Shandong Province(No.2012GGB01198)
文摘An implicit finite difference method is developed for a one-dimensional frac- tional percolation equation （FPE） with the Dirichlet and fractional boundary conditions. The stability and convergence are discussed for two special cases, i.e., a continued seep- age flow with a monotone percolation coefficient and a seepage flow with the fractional Neumann boundary condition. The accuracy and efficiency of the method are checked with two numerical examples.
基金funded by National Natural Science Foundation of China (Grant No. 41375038)China Meteorological Administration Special Public Welfare Research Fund (Grant No. GYHY201306040,GYHY201306075)
文摘Using numerical simulation data of the forward differential propagation shift （ΦDP） of polarimetric radar,the principle and performing steps of noise reduction by wavelet analysis are introduced in detail.Profiting from the multiscale analysis,various types of noises can be identified according to their characteristics in different scales,and suppressed in different resolutions by a penalty threshold strategy through which a fixed threshold value is applied,a default threshold strategy through which the threshold value is determined by the noise intensity,or a ΦDP penalty threshold strategy through which a special value is designed for ΦDP de-noising.Then,a hard-or soft-threshold function,depending on the de-noising purpose,is selected to reconstruct the signal.Combining the three noise suppression strategies and the two signal reconstruction functions,and without loss of generality,two schemes are presented to verify the de-noising effect by dbN wavelets：（1） the penalty threshold strategy with the soft threshold function scheme （PSS）; （2） the ΦDP penalty threshold strategy with the soft threshold function scheme （PPSS）.Furthermore,the wavelet de-noising is compared with the mean,median,Kalman,and finite impulse response （FIR） methods with simulation data and two actual cases.The results suggest that both of the two schemes perform well,especially when ΦDP data are simultaneously polluted by various scales and types of noises.A slight difference is that the PSS method can retain more detail,and the PPSS can smooth the signal more successfully.
基金Supported by the 2016 Basic Operational Outlays for the Research Activities of Centric University,Civil Aviation University of China under Grant No.3122016L010the National Natural Science Foundation of China under Grant No.11705279+1 种基金supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No.LR16A050001the National Natural Science Foundation of China under Grant Nos.11622538 and 61673150
文摘The network dismantling problem asks the minimum separate node set of a graph whose removal will break the graph into connected components with the size not larger than the one percentage of the original graph.This problem has attracted much attention recently and a lot of algorithms have been proposed. However, most of the network dismantling algorithms mainly focus on which nodes are included in the minimum separate set but overlook how to order them for removal, which will lead to low general efficiency during the dismantling process. In this paper,we reformulate the network dismantling problem by taking the order of nodes’ removal into consideration. An efficient dismantling sequence will break the network quickly during the dismantling processes. We take the belief-propagation guided decimation(BPD) dismantling algorithm, a state-of-the-art algorithm, as an example, and employ the node explosive percolation(NEP) algorithm to reorder the early part of the dismantling sequence given by the BPD. The proposed method is denoted as the NEP-BPD algorithm(NBA) here. The numerical results on Erd¨os-R′enyi graphs,random-regular graphs, scale-free graphs, and some real networks show the high general efficiency of NBA during the entire dismantling process. In addition, numerical computations on random graph ensembles with the size from 210 to219 exhibit that the NBA is in the same complexity class with the BPD algorithm. It is clear that the NEP method we used to improve the general efficiency could also be applied to other dismantling algorithms, such as Min-Sum algorithm,equal graph partitioning algorithm and so on.
基金Funded by the Outstanding Youth Foundation of Hubei Province of China (No.2004ABB019)
文摘The addition of graphite powder in conventional asphalt mixture can produced asp halt concrete with excellent electrical performance. Percolation theor y was employed to discuss the relation between the conductivity and graphite con tent of graphite-modified asphalt concrete. It was found that the results of pe rcolation model are consistent with experimental values. The percolation thresho ld of graphite-modified asphalt concrete is 10.94% graphite content account for the total volume of the binder phase consisting of asphalt and graphite. The cr itical exponent is 3.16, beyond the range of 1.6-2.1 for the standard lattice c ontinuous percolation problem. Its reason is that the tunnel conduction mec hanism originates near the critical percent content, which causes this system to be not universal. Tunnel mechanism is demonstrated by the nonlinear voltage-cu rrent characteristic near percolation threshold.The percolation model is able to well predict the formation and development of conductive network in graphite- modified asphalt concrete.
文摘A novel method for preparing conductive carbon black fllled polymer composites with low percolation threshold from polyurethane emulsion are reported in this paper. The experimental results indicate that with a rise in carbon black concentration the insulator-conductor transition in the emulsion blended composites occurs at 0.8-1.4vol%. In contrast, the solution blended composites exhibit drastic increase in conductivity at conducting filler fraction as high as 12.3-13.3vol%. It is demonstrated that the composites microstructure rather than chemical structure of the matrix polymer predominantly determines the electrical conduction performance of the composites.
文摘Gyro＇s drift is not only the main drift error which influences gyro＇s precision but also the primary factor that affects gyro＇s reliability. Reducing zero drift and random drift is a key problem to the output of a gyro signal. A three-layer de-nosing threshold algorithm is proposed based on the wavelet decomposition to dispose the signal which is collected from a running fiber optic gyro （FOG）. The coefficients are obtained from the three-layer wavelet packet decomposition. By setting the high frequency part which is greater than wavelet packet threshold as zero, then reconstructing the nodes which have been filtered out noise and interruption, the soft threshold function is constructed by the coefficients of the third nodes. Compared wavelet packet de-noise with forced de-noising method, the proposed method is more effective. Simulation results show that the random drift compensation is enhanced by 13.1%, and reduces zero drift by 0.052 6°/h.
基金Project supported by the National Program on Key Basic Research Project(973 Program)(No.2013CB228002)
文摘The nonlinear effects of unsteady multi-scale shale gas percolation,such as desorption,slippage,diffusion,pressure-dependent viscosity,and compressibility,are investigated by numerical simulation.A new general mathematical model of the problem is built,in which the Gaussian distribution is used to describe the inhomogeneous intrinsic permeability.Based on the Boltzmann transformation,an efficient semi-analytical method is proposed.The problem is then converted into a nonlinear equation in an integral form for the pressure field,and a related explicit iteration scheme is constructed by numerical discretization.The validation examples show that the proposed method has good convergence,and the simulation results also agree well with the results obtained from both numerical and actual data of two vertical fractured test wells in the literature.Desorption,slippage,and diffusion have significant influence on shale gas flows.The accuracy of the usual technique that the product of viscosity and compressibility is approximated as its value at the average formation pressure is examined.
文摘Making use of modern nonlinear physics theory and earthquake focus theory, combined with seismicity characteristics, the percolation model of earthquake activity is given in this paper. We take the seismogenic process of alarge earthquake as a phase transition process of percolation and apply the renormalization method to phase transition of percolation. The critical property of the system, which is like percolation probability exponential andcorrelative length exponential, etc, can be calculated under the fixed point as which in the renormalization transformation infinite correlative length in percolation phase transition is taken. The percolation phase transition process of two large earthquakes, which are Haicheng and Tangshan event occurred in 1975 and 1976 respectively, hasbeen discussed by means of seismicity data before and after two shocks.
