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Theoretical and experimental investigation of the resonance responses and chaotic dynamics of a bistable laminated composite shell in the dynamic snap-through mode

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 581-602页

作者： Meiqi WU Pengyu LV Hongyuan LI Jiale YAN Huiling DUAN Wei ZHANG State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China Nanchang Innovation Institute of Peking University Nanchang 330096China Department of Mechanics Guangxi UniversityNanning 530004China

The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic *** existence of the 1:1 resonance relationship between two order vibration modes of the system is *** resonance response of this class of bistable structures in the dynamic snap-through mode is investigated,and the four-dimensional(4D)nonlinear modulation equations are derived based on the 1:1 internal resonance relationship by means of the multiple scales *** Hopf bifurcation and instability interval of the amplitude frequency and force amplitude curves are *** discussion focuses on investigating the effects of key parameters,e.g.,excitation amplitude,damping coefficient,and detuning parameters,on the resonance *** numerical simulations show that the foundation excitation and the degree of coupling between the vibration modes exert a substantial effect on the chaotic dynamics of the ***,the significant motions under particular excitation conditions are visualized by bifurcation diagrams,time histories,phase portraits,three-dimensional(3D)phase portraits,and Poincare ***,the vibration experiment is carried out to study the amplitude frequency responses and bifurcation characteristics for the bistable laminated composite shell,yielding results that are qualitatively consistent with the theoretical results.

关键词： bistable laminated composite shell dynamic snap-through mode Hopf bifurcation chaotic dynamics vibration experiment

Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： ZHOU QianQian WEI YueGuang ZHOU YiChun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

Vacancy healing for stable perovskite solar cells via bifunctional potassium tartrate

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Journal of Energy Chemistry 2024年第1期88卷 64-70,I0002页

作者： Jing Dou Yue Ma Xiuxiu Niu Wentao Zhou Xueyuan Wei Jie Dou Zhenhua Cui Qizhen Song Tinglu Song Huanping Zhou Cheng Zhu Yang Bai Qi Chen Experimental Centre for Advanced Materials School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationBIC-ESATSchool of Materials Science and EngineeringPeking UniversityBeijing 100871China

Perovskite solar cell has gained widespread attention as a promising technology for renewable ***, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).

关键词： Perovskite Potassium tartrate Lead leakage Long-term stability

Modeling of the turbulent burning velocity for planar and Bunsen flames over a wide range of conditions

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Acta Mechanica Sinica 2022年第3期38卷 10-25,I0001页

作者： Zhen Lu Yue Yang State Key Laboratory for Turbulent and Complex Systems College of EngineeringPeking UniversityBeijing 100871China blc-esat Peking UniversityBeijing 100871China HEDPS-CAPT Peking UniversityBeijing 100871China

We develop and assess a model of the turbulent burning velocity ST over a wide range of *** aim is to obtain an explicit ST model for turbulent combustion modeling and flame *** model consists of sub models of the stretch factor and the turbulent flame *** stretch factor characterizes the flame response of turbulence stretch and incorporates detailed chemistry and transport effects with a lookup table of laminar counterflow *** flame area model captures the area growth based on Lagrangian statistics of propagating surfaces and considers the effects of turbulence length scales and fuel *** present model predicts sT via an algebraic expression without free *** assess the model using 490 cases of the direct numerical simulation or experiment reported from various research groups on planar and Bunsen flames over a wide range of conditions,covering fuels from hydrogen to n-dodecane,pressures from 1 to 30 atm,lean and rich mixtures,turbulence intensity ratios from 0.1 to 177.6,and turbulence length ratios from 0.5 to *** the scattering sT data in the literature,the comprehensive comparison shows that the proposed ST model has an overall good agreement over the wide range of conditions,with the averaged modeling error of 28.1%.

关键词： Turbulent burning velocity Turbulent premixed flame Flame speed

Discovery of Partial Differential Equations from Highly Noisy and Sparse Data with Physics-Informed Information Criterion

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Research 2024年第1期2023卷 247-259页

作者： Hao Xu Junsheng Zeng Dongxiao Zhang BIC-esat EREand SKLTCSCollege of EngineeringPeking UniversityBeijing 100871P.R.China Institute of Applied Physics and Computational Mathematics Beijing 100088P.R.China Eastern Institute for Advanced Study Eastern Institute of TechnologyNingbo 315200ZhejiangP.R.China National Center for Applied Mathematics Shenzhen(NCAMS) Southern University of Science and TechnologyShenzhen 518055GuangdongP.R.China Department of Mathematics and Theories Peng Cheng LaboratoryShenzhen 518000GuangdongP.R.China

Data-driven discovery of partial differential equations(PDEs)has recently made tremendous progress,and many canonical PDEs have been discovered successfully for proof of ***,determining the most proper PDE without prior references remains challenging in terms of practical *** this work,a physics-informed information criterion(PIC)is proposed to measure the parsimony and precision of the discovered PDE *** proposed PIC achieves satisfactory robustness to highly noisy and sparse data on 7 canonical PDEs from different physical scenes,which confirms its ability to handle difficult *** PIC is also employed to discover unrevealed macroscale governing equations from microscopic simulation data in an actual physical *** results show that the discovered macroscale PDE is precise and parsimonious and satisfies underlying symmetries,which facilitates understanding and simulation of the physical *** proposition of the PIC enables practical applications of PDE discovery in discovering unrevealed governing equations in broader physical scenes.

关键词： process canonical proof

Functions of Phytic Acid in Fabricating Metal-Free Carbocatalyst for Oxidative Coupling of Benzylamines

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Chinese Journal of Chemistry 2020年第11期38卷 1292-1298页

作者： Chuanchuan Zhao Yongjun Gao Ziyi Zhang Ding Ma Key Laboratory of Medicinal Chemistry and Molecular Diognosis of Ministry of ducation Ccollege of Cchemistry and Emvironmental cienceHebei UniversityBaodingHebei 071002China Beijing Nationdl laboratory for Molecular Sciences College of Chemistry and Molecular Engineering and Cllege of Engineeringand BlC-ESATPeking UniversityBeijing 100871China

of main observation and conclusion Sustainable phytic acid and cellulose are selected as precursors to fabricate P-doped carbon material(C-P-500),which possesses the high surface area and exhibits excellent catalytic activity and stability in the oxidative coupling of benzylamines(conversion>95%,yield>95%).During the carbonization of cellulose in the muffle furnace,phytic acid can efficiently prevent the cellulose-derived carbon from combustion and create micro/meso porous structure because of its special function of fire *** experiments and characterizations demonstrate that P-containing groups anchoring on C-P-500 improve the catalytic performance of carbocatalyst in the oxidation of benzylamines to *** excellent catalytic activity of C-P-500 should be contributed collectively by carbonyl and P=0(0H)2 *** to the sustainable property of precursors and simple methodology for fabricating P-doped carbocatalyst,along with the moderate reaction conditions,it is a green catalytic system for the oxidative coupling of benzylamines to imines.

关键词： amines catalyst oxidative

Biogenic volatile organic compounds dominated the near-surface ozone generation in Sichuan Basin,China,during fall and wintertime

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Journal of Environmental Sciences 2024年第7期141卷 215-224页

作者： Dasheng Huang Qing Li Yan Han Shi-Yong Xia Jiawei Zhou Hanxiong Che Keding Lu Fumo Yang Xin Long Yang Chen Research Center for Atmospheric Environment Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China College of Resources and Environment Chongqing SchoolUniversity of the Chinese Academy of Sciences(UCAS Chongqing)Chongqing 400714China College of Environmental and Chemical Engineering Chongqing Three Gorges UniversityChongqing 404199China Key Laboratory for Urban Habitat Environmental Science and Technology School of Environment and EnergyPeking University Shenzhen Graduate SchoolLishui RoadNanshan DistrictShenzhen 518055China SKL-ESPC and BIC-esat College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China College of Architecture&Environment Sichuan UniversityChengdu 610065China

The complex air pollution driven by both Ozone(O_(3))and fine particulate matter(PM2.5)sig nificantly influences the air quality in the Sichuan Basin(SCB).Understanding the O_(3)for mation during autumn and winter is necessary to understand the atmospheric oxidative ***,continuous in-site field observations were carried out during the late summer,early autumn and winter of 2020 in a rural area of *** total volatile organic compounds(VOCs)concentration reported by a Proton-Transfer-Reaction Time-of Flight Mass Spectrometry(PTR-ToF-MS)were 13.66±9.75 ppb,5.50±2.64 ppb,and 9.41±5.11 ppb in late summer,early autumn and winter,*** anthropogenic VOCs(AVOCs)and biogenic VOCs(BVOCs)were 8.48±7.92 ppb and 5.18±2.99 ppb in late sum mer,3.31±1.89 ppb and 2.19±0.93 ppb in autumn,and 6.22±3.99 ppb and 3.20±1.27ppb in winter.A zero-dimensional atmospheric box model was employed to investigate the sensitivity of O_(3)-precursors by relative incremental reactivity(RIR).The RIR values of AV OCs,BVOCs,carbon monoxide(CO),and nitrogen oxides(NOx)were 0.31,0.71,0.09,and-0.36 for late summer,0.24,0.59,0.22,and-0.38 for early autumn,and 0.30,0.64,0.33 and-0.70 for winter,and the results showed that the O_(3)formation of sampling area was in the VOC-limited region,and O_(3)was most sensitive to BVOCs(with highest RIR values,>0.6)This study can be helpful in understanding O_(3)formation and interpreting the secondary formation of aerosols in the winter.

关键词： VOCs PTR-MS Model Ozone

Initialisation of a hybrid AC/DC power system for harmonic stability analysis using a power flow formulation

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High Voltage 2020年第5期5卷 534-542页

作者： Aleksandra Lekić Hakan Ergun Jef Beerten Department of Electrical Engineering(esat-ELECTA) KU LeuvenLeuvenBelgium

This study presents the initialisation of a hybrid alternating current/direct current(AC/DC)power system to determine the operation point around which the system is linearised as a starting point for an electromagnetic or harmonic stability *** this end,each AC or DC power system component is modelled in the Fourier transform domain and further adjusted to a simplified representation compatible with a power flow *** study also presents how voltage source converter(VSC)high-voltage DC-based systems can be analysed when the different VSC controls are *** result of the power flow solution is then used for the power converters’initialisation.

关键词： AC/DC system formulation

Cross-scale indentation scaling relationships of strain gradient plastic solids:Influence of inclusions near the indenter tip

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Acta Mechanica Sinica 2022年第1期38卷 50-58页

作者： Zhijie Yu Yueguang Wei Department of Mechanics and Engineering Science College of EngineeringB/C-ESATPeking UniversityBeijing 100871China

The indentation test is a localized testing technique;therefore,the role of the material size-effect and local non-uniformity is of much *** influence of the heterogeneity in size-independent materials has been studied *** present work detailedly investigated the influence of the material size-effect and heterogeneity(inclusions near the indenter tip)on the indentation hardness using a size-dependent strain gradient plastic *** it was found that when considering the material size-ffect,shallow hard inclusions in the heterogeneous materials more significantly enhance the material indentation hardness compared with the size-independent materials which are based on the conventional plastic *** hardening effect is be-lieved to be related to the elevation of the load and local constraints of large *** effect of material inhomogeneity mainly comes from the non-uniformity of the structure rather than the inclusion modulus itself especially when the size-effect is involved,and the transition range of the inclusion modulus'influence is pretty *** effect of non-uniformity becomes negligible after the initial inclusion depth is larger than its *** horizontal offset of the indenter from the inclusion is also of much sensitivity to the influence of the heterogeneous *** paper focuses on the scaling relationships in micro-and nanoindentation,the influence of non-uniformity in microscopic materials is studied and supplemented as well.

关键词： Scaling relationships Conical nanoindentation Material size-effect Strain gradient theory