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Sulfur vacancies and heterogeneous interfaces promote high performance sodium storage of bimetallic chalcogenide hollow nanospheres

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Journal of Energy Chemistry 2024年第8期95卷 596-610页

作者： Shiyue Cao Xiaoting Xu Qiming Liu Huijuan Zhu Ting Hu Key laboratory of Artificial Micro-and Nano-structures of Ministry of Education School of Physics and Technology Wuhan University

Transition metal sulfides have high theoretical capacities and are considered as potential anode materials for sodium-ion batteries.However,due to low inherent conductivity and significant volume expansion,the electrochemical performance is greatly limited.In this study,a nickel/manganese sulfide material(Ni0.96Sx/MnSy-NC) with adjustable sulfur vacancies and heterogeneous hollow spheres was prepared using a simple method.The introduction of a concentration-adjustable sulfur vacancy enables the generation of a heterogeneous interface between bimetallic sulfide and sulfur vacancies.This interface collectively creates an internal electric field,improving the mobility of electrons and ions,increasing the number of electrochemically active sites,and further optimizing the performance of Na+storage.The direction of electron flow is confirmed by Density functional theory（DFT） calculations.The hollow nano-spherical material provides a buffer for expansion,facilitating rapid transfer kinetics.Our innovative discovery involves the interaction between the ether-based electrolyte and copper foil,leading to the formation of Cu9S5,which grafts the active material and copper current collector,reinforcing mechanical supporting.This results in a new heterostructure of Cu9S5with Ni0.96Sx/MnSy,contributing to the stabilization of structural integrity for long-cycle performance.Therefore,Ni0.96Sx/MnSy-NC exhibits excellent electrochemical properties following our modification route.Regarding stability performance,Ni0.96Sx/MnSy-NC demonstrates an average decay rate of 0.00944% after 10,000 cycles at an extremely high current density of 10000 mA g-1,A full cell with a high capacity of 304.2 mA h g-1was also successfully assembled by using Na3V2（PO4）3/C as the cathode.This study explores a novel strategy for interface/vacancy co-modification in the fabrication of high-performance sodium-ion batteries electrode.

关键词： Heterogeneous interface Interactions Sodium ion batteries Sulfur vacancies

Dynamic characteristics of multi-span spinning beams with elastic constraints under an axial compressive force

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 295-310页

作者： Xiaodong GUO Zhu SU Lifeng WANG State Key laboratory of Mechanics and Control for Aerospace structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is proposed.The displacement and bending angle functions are represented through an improved Fourier series,which ensures the continuity of the derivative at the boundary and enhances the convergence.The exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange equation.The efficiency and accuracy of the present method are validated in comparison with the finite element method(FEM)and other methods.The effects of the boundary spring stiffness,the number of spans,the spinning velocity,and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are studied.The results show that the present method can freely simulate any boundary constraints without modifying the solution process.The elastic range of linear springs is larger than that of torsion springs,and it is not affected by the number of spans.With an increase in the axial compressive force,the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger,while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.

关键词： multi-span spinning beam elastic constraint improved Fourier series free vibration semi-analytical solution

Vibration of black phosphorus nanotubes via orthotropic cylindrical shellmodel

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 166-173页

作者： Minglei He Lifeng Wang State Key laboratory of Mechanics and Control for Aerospace structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Black phosphorus nanotubes(BPNTs)may have good properties and potential applications.Determining thevibration property of BPNTs is essential for gaining insight into the mechanical behaviour of BPNTs and designingoptimized nanodevices.In this paper,the mechanical behaviour and vibration property of BPNTs are studied viaorthotropic cylindrical shell model and molecular dynamics(MD)simulation.The vibration frequencies of twochiral BPNTs are analysed systematically.According to the results of MD calculations,it is revealed that thenatural frequencies of two BPNTs with approximately equal sizes are unequal at each order,and that the naturalfrequencies of armchair BPNTs are higher than those of zigzag BPNTs.In addition,an armchair BPNTs witha stable structure is considered as the object of research,and the vibration frequencies of BPNTs of differentsizes are analysed.When comparing the MD results,it is found that both the isotropic cylindrical shell modeland orthotropic cylindrical shell model can better predict the thermal vibration of the lower order modes of thelonger BPNTs better.However,for the vibration of shorter and thinner BPNTs,the prediction of the orthotropiccylindrical shell model is obviously superior to the isotropic shell model,thereby further proving the validity ofthe shell model that considers orthotropic for BPNTs.

关键词： Orthotropic cylindrical shell Molecular dynamics simulation Black phosphorus nanotube Vibration

Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement

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China Ocean Engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan REN Xiao-hui HOU Hao HAO Lian-hong College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key laboratory of marine Civil Engineering Materials and structures Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Dynamic response of sandwich panel attached with a double mass-spring-damping system to shallow-buried explosion:Analytical modeling

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Science China(Technological Sciences) 2024年第2期67卷 568-586页

作者： ZHANG DuJiang ZHAO ZhenYu GAO HuiYao LU TianJian State Key laboratory of Mechanics and Control for Aerospace structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China MIIT Key laboratory of Multifunctional Lightweight Materials and structures(MLMS) Nanjing University of Aeronautics and AstronauticsNanjing 210016China

How to ensure the safety of occupants has become a challenge for protective design of armored vehicles against intensive blast loadings.In this study,for armored vehicles subjected to shallow-buried explosions,an analytical model was established to characterize the dynamic performance of an all-metallic sandwich floorboard attached with a double mass-spring-damping system(mimicking seat and occupant),with the former consisting of a front face,a core and a rear face.For validation,numerical simulations with the method of finite elements(FE)were performed.Good agreement between analytical predictions and numerical results was achieved.The analytical model was then employed to quantify the effects of explosive mass,yield stress of material make,configurational parameters of sandwich panel,spring stiffness,and damping coefficient on dynamic response of the sandwich panel and double mass-spring-damping system.With increasing explosive mass and decreasing yield stress of material make,the peak displacements of rear face,seat and occupant were all found to increase.As core relative density was increased,these peak displacements also increased when the ratio of face thickness to core height was relatively small.Increasing the ratio of face thickness to core height led to increased peak accelerations of seat and occupant.The peak displacement of rear face was insensitive to the increase of either spring stiffness or damping coefficient,while the peak acceleration of occupant increased with increasing spring stiffness.Upon increasing the damping coefficient between the rear face and seat or that between the seat and occupant or both,the peak acceleration of occupant increased.With occupant safety duly considered,the proposed analytical model provides useful guidance for designing high-performance protective structures for armored vehicles subjected to intensive blast loadings.

关键词： analytical model shallow-buried explosion sandwich panel occupant safety mass-spring-damping system

A novel efficient energy absorber with free inversion of a metal foam-filled circular tube

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 1-14页

作者： Jianxun ZHANG Jinwen BAI State Key laboratory for Strength and Vibration of Mechanical structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an 710049China

In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with the results of the finite element(FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption(SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone.

关键词： metal foam-filled circular tube(MFFCT) free inversion load-carrying capacity energy absorption

Fast charge transfer kinetics in Sv-ZnIn_(2)S_(4)/Sb_(2)S_(3)S-scheme heterojunction photocatalyst for enhanced photocatalytic hydrogen evolution

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Rare Metals 2024年第2期43卷 533-542页

作者： Wei Li Jia-Jun Li Zhi-Fei Liu Hong-Yu Ma Peng-Fei Fang Rui Xiong Jian-Hong Wei Key laboratory of Artificial Micro-and Nano-structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan430072China

Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution performance.Herein,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was designed.The introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution reaction.Furthermore,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of charges.As a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) samples.Based on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is proposed.This work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.

关键词： ZnIn_(2)S_(4) nanosheets S-scheme heterojunction Sulfur vacancy Charge transfer and separation Photocatalytic H_(2)evolution

Findings on three endocommensal scuticociliates(Protista,Ciliophora)from freshwater mollusks,including their morphology and molecular phylogeny with descriptions of two new species

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marine Life Science & Technology 2024年第2期6卷 212-235页

作者： Tao Li Tengyue Zhang Mingjian Liu Zhe Zhang Jiachen Zhang Junhua Niu Xiangrui Chen Saleh A.Al‑Farraj Weibo Song Institute of Evolution and marine Biodiversity Ocean University of China and Key Laboratory of Evolution and Marine Biodiversity(Ministry of Education)Qingdao 266003China The Key laboratory of Zoological Systematics and Application College of Life SciencesHebei UniversityBaoding 071002China College of marine Life Sciences Ocean University of ChinaQingdao 266003China School of marine Sciences Ningbo UniversityNingbo 315800China Zoology Department College of ScienceKing Saud University11451 RiyadhSaudi Arabia laboratory for marine Biology and Biotechnology Laoshan LaboratoryQingdao 266237China

Species of the ciliate genera Myxophyllum and Conchophthirus are found as endocommensals of terrestrial and freshwater mollusks,respectively.So far,there have been few studies of these genera and morphological data for most members are often incomplete.In the present work,two new species,Myxophyllum weishanense sp.***.and Conchophthirus paracurtus sp.nov.,and a known species,Conchophthirus lamellidens,were isolated from hosts in Lake Weishan Wetland,China.Taxonomic studies indicate that M.weishanense sp.***.can be recognized mainly by the combination of about 60 somatic kineties on both ventral and dorsal sides and the presence of caudal cilia.Conchophthirus paracurtus sp.***.differs from congeners in its body shape and size,having a glabrous area on the posterior right side,and having fewer somatic kineties.In addition,differences in their ITS2(Internally Transcribed Spacer 2)secondary structures support the discrimination of the two new species from their highly similar congeners.An improved diagnosis for the poorly known species,C.lamel-lidens is also provided.Phylogenetic analyses reveal that members of the genus Myxophyllum belong to a fully supported clade that is sister to a large,poorly supported clade consisting of Hemispeiridae,Ancistridae,and several lineages of the nonmonophyletic Cyclidiidae.The Myxophyllum clade also includes Protophyra ovicola JQ956552,a possible misidenti-fication.Sequences of the two new Conchophthirus species cluster with other congeners in a fully supported clade that is unrelated to either the‘typical’thigmotrichs or to pleuronematids,thus conflicting with the traditional classification,and may represent an orphan scuticociliate lineage.

关键词： Ciliates Endocommensal ITS2 secondary structure Mollusks New taxa Wetland

Fluid-structure interaction simulation for multi-body flexible morphing structures

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Chinese Journal of Aeronautics 2024年第2期37卷 137-147页

作者： Wenzhi GUO Yongtao SHUI Lu NIE Gang CHEN State Key laboratory of Strength and Vibration for Mechanic structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China China Academy of Launch Vehicle Technology Beijing 100076China China Academy of Aerospace Science and Innovation Beijing 100086China Shannxi Key laboratory of Service Environment and Control for Flight Vehicles Xi’an Jiaotong UniversityXi’an 710049China

The multi-body flexible morphing airfoil can improve the aerodynamic characteristics based on different flight missions continuously.Recently researches have focused on the unsteady aerodynamic characteristics of flexible wings under passive actuation.However,the unsteady aerodynamic characteristics with the fluid-structure interaction effects in the multi-body active actuation process of morphing airfoil deserve further investigation.In this paper,a fluid-structure coupled simulation method for multi-body flexible morphing airfoil with active actuation subsystem was investigated,and the aerodynamic characteristics during deformation were compared with different skin flexibility,flow field environment,actuation mode and actuation time.The numerical results show that for the steady aerodynamic,the skin flexibility can improve the stability efficiency.In the unsteady process,the change trend of the transient lift coefficient and pitching moment are consistent with those of the active drive characteristics,while the instantaneous lift-drag ratio coefficient is greatly affected by the driving mode and can be improved by increasing the driving duration.

关键词： Fluid-structure interaction Multi-body dynamics modeling Flexible structures Aerodynamics Morphing wings