Although phase separation is a ubiquitous phenomenon, the interactions between multiple components make it difficult to accurately model and predict. In recent years, machine learning has been widely used in physics s...Although phase separation is a ubiquitous phenomenon, the interactions between multiple components make it difficult to accurately model and predict. In recent years, machine learning has been widely used in physics simulations. Here,we present a physical information-enhanced graph neural network(PIENet) to simulate and predict the evolution of phase separation. The accuracy of our model in predicting particle positions is improved by 40.3% and 51.77% compared with CNN and SVM respectively. Moreover, we design an order parameter based on local density to measure the evolution of phase separation and analyze the systematic changes with different repulsion coefficients and different Schmidt numbers.The results demonstrate that our model can achieve long-term accurate predictions of order parameters without requiring complex handcrafted features. These results prove that graph neural networks can become new tools and methods for predicting the structure and properties of complex physical systems.展开更多
Optical physical unclonable functions(PUFs)have emerged as a promising strategy for effective and unbreakable anti-counterfeiting.However,the unpredictable spatial distribution and broadband spectra of most optical PU...Optical physical unclonable functions(PUFs)have emerged as a promising strategy for effective and unbreakable anti-counterfeiting.However,the unpredictable spatial distribution and broadband spectra of most optical PUFs complicate efficient and accurate verification in practical anti-counterfeiting applications.Here,we propose an optical PUF-based anti-counterfeiting label from perovskite microlaser arrays,where randomness is introduced through vapor-induced microcavity deformation.The initial perovskite microdisk laser arrays with regular positions and uniform sizes are fabricated by femtosecond laser direct ablation.By introducing vapor fumigation to induce random deformations in each microlaser cavity,a laser array with completely uneven excitation thresholds and narrow-linewidth lasing signals is obtained.As a proof of concept,we demonstrated that the post-treated laser array can provide fixed-point and random lasing signals to facilitate information encoding.Furthermore,different emission states of the lasing signal can be achieved by altering the pump energy density to reflect higher capacity information.A threefold PUF(excited under three pump power densities)with a resolution of 5×5 pixels exhibits a high encoding capacity(1.43×10^(45)),making it a promising candidate to achieve efficient authentication and high security with anti-counterfeiting labels.展开更多
Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on th...Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on the dynamic performance of the structure using the finite element method(FEM).To reduce the heavy computational burden,a surrogate model of a dome structure was constructed to solve this problem.The dynamic global sensitivity of elastic and elastoplastic structures was analyzed in the uncertainty quantification framework using fully quantitative variance-and distribution-based methods through the surrogate model.The model considered the predominant sources of uncertainty that have a significant influence on the performance of the dome structure.The effects of the variables on the structural performance indicators were quantified using the sensitivity index values of the different performance states.Finally,the effects of the sample size and correlation function on the accuracy of the surrogate model as well as the effects of the surrogate accuracy and failure probability on the sensitivity index values are discussed.The results show that surrogate modeling has high computational efficiency and acceptable accuracy in the uncertainty quantification of large-scale structures subjected to earthquakes in comparison to the conventional FEM.展开更多
Rational design of single-metal atom sites in carbon substrates by a flexible strategy is highly desired for the preparation of high-performance catalysts for metal-air batteries.In this study,biomass hydrogel reactor...Rational design of single-metal atom sites in carbon substrates by a flexible strategy is highly desired for the preparation of high-performance catalysts for metal-air batteries.In this study,biomass hydrogel reactors are utilized as structural templates to prepare carbon aerogels embedded with single iron atoms by controlled pyrolysis.The tortuous and interlaced hydrogel chains lead to the formation of abundant nanowrinkles in the porous carbon aerogels,and single iron atoms are dispersed and stabilized within the defective carbon skeletons.X-ray absorption spectroscopy measurements indicate that the iron centers are mostly involved in the coordination structure of FeN_(4),with a minor fraction(ca.1/5)in the form of FeN_(3)C.First-principles calculations show that the FeN_(x) sites in the Stone-Wales configurations induced by the nanowrinkles of the hierarchically porous carbon aerogels show a much lower free energy than the normal counterparts.The resulting iron and nitrogen-codoped carbon aerogels exhibit excellent and reversible oxygen electrocatalytic activity,and can be used as bifunctional cathode catalysts in rechargeable Zn-air batteries,with a performance even better than that based on commercial Pt/C and RuO_(2) catalysts.Results from this study highlight the significance of structural distortions of the metal sites in carbon matrices in the design and engineering of highly active single-atom catalysts.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11702289)the Key Core Technology and Generic Technology Research and Development Project of Shanxi Province,China(Grant No.2020XXX013)。
文摘Although phase separation is a ubiquitous phenomenon, the interactions between multiple components make it difficult to accurately model and predict. In recent years, machine learning has been widely used in physics simulations. Here,we present a physical information-enhanced graph neural network(PIENet) to simulate and predict the evolution of phase separation. The accuracy of our model in predicting particle positions is improved by 40.3% and 51.77% compared with CNN and SVM respectively. Moreover, we design an order parameter based on local density to measure the evolution of phase separation and analyze the systematic changes with different repulsion coefficients and different Schmidt numbers.The results demonstrate that our model can achieve long-term accurate predictions of order parameters without requiring complex handcrafted features. These results prove that graph neural networks can become new tools and methods for predicting the structure and properties of complex physical systems.
基金National Natural Science Foundation of China (61925506)Natural Science Foundation of Shanghai (20JC1414605)+1 种基金Hangzhou Science and Technology Bureau of Zhejiang Province (TD2020002)Academic/Technology Research Leader Program of Shanghai (23XD1404500)。
文摘Optical physical unclonable functions(PUFs)have emerged as a promising strategy for effective and unbreakable anti-counterfeiting.However,the unpredictable spatial distribution and broadband spectra of most optical PUFs complicate efficient and accurate verification in practical anti-counterfeiting applications.Here,we propose an optical PUF-based anti-counterfeiting label from perovskite microlaser arrays,where randomness is introduced through vapor-induced microcavity deformation.The initial perovskite microdisk laser arrays with regular positions and uniform sizes are fabricated by femtosecond laser direct ablation.By introducing vapor fumigation to induce random deformations in each microlaser cavity,a laser array with completely uneven excitation thresholds and narrow-linewidth lasing signals is obtained.As a proof of concept,we demonstrated that the post-treated laser array can provide fixed-point and random lasing signals to facilitate information encoding.Furthermore,different emission states of the lasing signal can be achieved by altering the pump energy density to reflect higher capacity information.A threefold PUF(excited under three pump power densities)with a resolution of 5×5 pixels exhibits a high encoding capacity(1.43×10^(45)),making it a promising candidate to achieve efficient authentication and high security with anti-counterfeiting labels.
基金the Key Project of the Natural Science Foundation of Tianjin City(No.19JCZDJC39300)is acknowledged.
文摘Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on the dynamic performance of the structure using the finite element method(FEM).To reduce the heavy computational burden,a surrogate model of a dome structure was constructed to solve this problem.The dynamic global sensitivity of elastic and elastoplastic structures was analyzed in the uncertainty quantification framework using fully quantitative variance-and distribution-based methods through the surrogate model.The model considered the predominant sources of uncertainty that have a significant influence on the performance of the dome structure.The effects of the variables on the structural performance indicators were quantified using the sensitivity index values of the different performance states.Finally,the effects of the sample size and correlation function on the accuracy of the surrogate model as well as the effects of the surrogate accuracy and failure probability on the sensitivity index values are discussed.The results show that surrogate modeling has high computational efficiency and acceptable accuracy in the uncertainty quantification of large-scale structures subjected to earthquakes in comparison to the conventional FEM.
基金Y.Z.acknowledges support from the National Natural Science Foundation of China(21972169,21773311,and 21473257)Hunan Provincial Science and Technology Plan Project(2017TP1001)+2 种基金The authors thank Dr.Yongfeng Hu of the Canadian Light Source(Saskatoon)and Dr.JengLung Chen of the National Synchrotron Radiation Research Center(Taiwan)for their assistance in the acquisition of XANES and EXAFS data,and Dr.Yi Peng(UCSC)for helpful discussion.T.H.is supported by a research fellowship from the China Scholarship Council(201806370027)J.V.J.acknowledges support from the Army Research Office under contract W911NF-17-1-0473S.W.C.acknowledges support from the National Science Foundation(CHE-1710408 and CHE-1900235).
文摘Rational design of single-metal atom sites in carbon substrates by a flexible strategy is highly desired for the preparation of high-performance catalysts for metal-air batteries.In this study,biomass hydrogel reactors are utilized as structural templates to prepare carbon aerogels embedded with single iron atoms by controlled pyrolysis.The tortuous and interlaced hydrogel chains lead to the formation of abundant nanowrinkles in the porous carbon aerogels,and single iron atoms are dispersed and stabilized within the defective carbon skeletons.X-ray absorption spectroscopy measurements indicate that the iron centers are mostly involved in the coordination structure of FeN_(4),with a minor fraction(ca.1/5)in the form of FeN_(3)C.First-principles calculations show that the FeN_(x) sites in the Stone-Wales configurations induced by the nanowrinkles of the hierarchically porous carbon aerogels show a much lower free energy than the normal counterparts.The resulting iron and nitrogen-codoped carbon aerogels exhibit excellent and reversible oxygen electrocatalytic activity,and can be used as bifunctional cathode catalysts in rechargeable Zn-air batteries,with a performance even better than that based on commercial Pt/C and RuO_(2) catalysts.Results from this study highlight the significance of structural distortions of the metal sites in carbon matrices in the design and engineering of highly active single-atom catalysts.