Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on ...Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on the fact that a variational reversible locally resonant elastic metamaterial(LREM) with four configurations is proposed. Through a combination of theoretical analysis and numerical simulations, this newly designed metamaterial is proven to exhibit different bandgap ranges and vibration attenuation properties in each configuration. Especially, there is tunable anisotropy shown in these configurations, which enables the bandgaps in two directions to be separated or overlapped. A model with a bandgap shifting ratio(BSR) of 100% and an overlap ratio of 25% is set to validate the multistable strategy feasibility. The proposed design strategy demonstrates significant potentials for applications in versatile scenarios.展开更多
To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The result...To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The results indicate that the average grain size and basal texture intensity of the hot-rolled Mg-1 Al-0.7Sm-0.3Ca alloy are significantly reduced compared to the hot-rolled Mg-1Al-0.3Ca alloy.This reduction can be attributed to the pinning effect of grain boundaries and grain refinement facilitated by the presence of the fine Al2Sm phase.Additionally,the addition of Sm leads to an increase in yield strength and ultimate tensile strength,along with a decrease in elongation.This can be attributed to the combined effects of the strengthening mechanism provided by a significant number of Al2Sm particles and the stress concentration occurring at the sharp corners of these particles.Significantly,this study proposes the substitution of expensive RE elements with more cost-effective Sm in the design of Mg alloys for low-alloy systems.The excellent mechanical properties of the Mg-1Al-0.7Sm-0.3Ca alloy provide a reference for the future development of high-performance Mg alloys.展开更多
Star sensors are an important means of autonomous navigation and access to space information for satellites.They have been widely deployed in the aerospace field.To satisfy the requirements for high resolution,timelin...Star sensors are an important means of autonomous navigation and access to space information for satellites.They have been widely deployed in the aerospace field.To satisfy the requirements for high resolution,timeliness,and confidentiality of star images,we propose an edge computing algorithm based on the star sensor cloud.Multiple sensors cooperate with each other to forma sensor cloud,which in turn extends the performance of a single sensor.The research on the data obtained by the star sensor has very important research and application values.First,a star point extraction model is proposed based on the fuzzy set model by analyzing the star image composition,which can reduce the amount of data computation.Then,a mappingmodel between content and space is constructed to achieve low-rank image representation and efficient computation.Finally,the data collected by the wireless sensor is delivered to the edge server,and a differentmethod is used to achieve privacy protection.Only a small amount of core data is stored in edge servers and local servers,and other data is transmitted to the cloud.Experiments show that the proposed algorithm can effectively reduce the cost of communication and storage,and has strong privacy.展开更多
Developing artificial catalysts that mimic the functionality of enzymes and adapt to the surrounding microenvironment to achieve specific activity and selectivity is a fascinating research area yet remains a great cha...Developing artificial catalysts that mimic the functionality of enzymes and adapt to the surrounding microenvironment to achieve specific activity and selectivity is a fascinating research area yet remains a great challenge.In this work,we present a meticulously designed strategy for the successful encapsulation of ultrasmall metal clusters(MCs)within an amine-type porous organic cage(POC)through electrostatic complexation,phase transfer,and alcohol reduction processes.The amine cage showcases an intriguing and customizable feature that allows for the regulation of the surrounding microenvironment of the confined MCs through a feasible postmodifi-cation approach.This functionalization of cage skeleton further facilitates precise adjustment to the surface electronic state of Pd cluster,thereby influencing the adsorption behavior of substrate.Consequently,this controlled regulation leads to modified activity and chemoselectivity in the catalytic hydrogenation of halogenated nitrobenzene.Importantly,the investigation of the correlation between the surrounding microenvironment,substrate adsorption,and catalytic performance in the POC-immobilized MCs system has not been previously reported.We anticipate that our research will provide valuable insights in this field.展开更多
基金supported by the National Natural Science Foundation of China(No.52192633)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2025JC-YBMS-050)。
文摘Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on the fact that a variational reversible locally resonant elastic metamaterial(LREM) with four configurations is proposed. Through a combination of theoretical analysis and numerical simulations, this newly designed metamaterial is proven to exhibit different bandgap ranges and vibration attenuation properties in each configuration. Especially, there is tunable anisotropy shown in these configurations, which enables the bandgaps in two directions to be separated or overlapped. A model with a bandgap shifting ratio(BSR) of 100% and an overlap ratio of 25% is set to validate the multistable strategy feasibility. The proposed design strategy demonstrates significant potentials for applications in versatile scenarios.
文摘To facilitate the industrial application of wrought Mg alloys,this study explores the impact of the rare earth(RE) element Sm on the microstructure and mechanical properties of hot-rolled Mg-1Al-0.3Ca alloy.The results indicate that the average grain size and basal texture intensity of the hot-rolled Mg-1 Al-0.7Sm-0.3Ca alloy are significantly reduced compared to the hot-rolled Mg-1Al-0.3Ca alloy.This reduction can be attributed to the pinning effect of grain boundaries and grain refinement facilitated by the presence of the fine Al2Sm phase.Additionally,the addition of Sm leads to an increase in yield strength and ultimate tensile strength,along with a decrease in elongation.This can be attributed to the combined effects of the strengthening mechanism provided by a significant number of Al2Sm particles and the stress concentration occurring at the sharp corners of these particles.Significantly,this study proposes the substitution of expensive RE elements with more cost-effective Sm in the design of Mg alloys for low-alloy systems.The excellent mechanical properties of the Mg-1Al-0.7Sm-0.3Ca alloy provide a reference for the future development of high-performance Mg alloys.
基金supported by Science and Technology Rising Star of Shaanxi Youth (No.2021KJXX-61)The Open Project Program of the State Key Lab of CAD&CG,Zhejiang University (No.A2206).
文摘Star sensors are an important means of autonomous navigation and access to space information for satellites.They have been widely deployed in the aerospace field.To satisfy the requirements for high resolution,timeliness,and confidentiality of star images,we propose an edge computing algorithm based on the star sensor cloud.Multiple sensors cooperate with each other to forma sensor cloud,which in turn extends the performance of a single sensor.The research on the data obtained by the star sensor has very important research and application values.First,a star point extraction model is proposed based on the fuzzy set model by analyzing the star image composition,which can reduce the amount of data computation.Then,a mappingmodel between content and space is constructed to achieve low-rank image representation and efficient computation.Finally,the data collected by the wireless sensor is delivered to the edge server,and a differentmethod is used to achieve privacy protection.Only a small amount of core data is stored in edge servers and local servers,and other data is transmitted to the cloud.Experiments show that the proposed algorithm can effectively reduce the cost of communication and storage,and has strong privacy.
基金supported by the Innovation Program for Quantum Science and Technology(Grant No.2024ZD0302403)the National Natural Science Foundation of China(Grant No.12434015)the Shanxi“1331 Project”Key Subjects Construction.
文摘Continuous-variable(CV)quantum light sources are the essential resource for quantum computation.Integrated CV quantum light sources offer a scalable pathway by harnessing low-loss nonlinear materials,versatile device architectures,and CMOS-compatible fabrication processes enabled by integrated photonics platforms.In this review,we briefly introduce recent progress on integrated CV quantum light sources,including single-mode squeezed states,two-mode squeezed states,and multimode entangled states.The key performance metrics of CV quantum light sources,such as the squeezing level,bandwidth,purity,and mode multiplexing,are analyzed.We highlight representative implementations of lithium niobate,silicon nitride,and silica platforms for CV quantum light sources and discuss major challenges for realizing integrated large-scale and fault-tolerant CV quantum computation.
基金financially supported by the National Natural Science Foundation of China(51973079)the Science and Technology Development Plan of Jilin Province,China(20220402008GH)。
文摘设计分层异质结构作为一种经济且高效的催化剂,以实现水分解的电子和界面工程,是能源存储与转化中的一个有意义的决策.在这项工作中,通过静电纺丝-碳化-电沉积的策略,制备了负载在嵌入Co纳米颗粒的碳纤维上的非晶态NiFeS纳米片(Co-C/NiFeS纳米纤维)催化剂.该催化剂具有优异的析氧反应(OER)活性,在1 mol L^(-1)KOH溶液中,在10 mA cm^(-2)下的过电位为233 mV,Tafel斜率为53.1 mV dec^(-1),同时还具有良好的析氢反应活性.此外,由Co-C/NiFeS纳米纤维作为阳极,商用Pt/C作为阴极构建的碱性Pt/C‖Co-C/NiFeS电解槽在10 mA cm^(-2)下实现1.48 V的低电池电压,优于基准Pt/C‖RuO_(2)电解槽和许多其他报道的电解槽.作为双功能电催化剂,Co-C/NiFeS‖Co-C/NiFeS自身组装的电解槽表现出70小时的长期稳定性,显著优于Pt/C‖RuO_(2)电解槽.该催化剂显著的OER性能得益于Co-C纳米纤维核与非晶NiFeS纳米片鞘组成的明显分层异质结构以及生成的高导电碳纤维基底,这些结构特征赋予该材料丰富的暴露活性位点、良好的导电性和坚固的结构稳定性.因此,这项工作提出了一种简单且有效的方法来制备具有优异电催化性能的非贵金属基催化剂,以用于实际的能量转换和存储.
基金supported by the National Natural Science Foundation of China(grant nos.22071008 and 52003029)the High-level Overseas Talents Program of China,the Excellent Young Scholars Research Fund from the Beijing Institute of Technology,and the Central University Basic Research Fund of China(grant no.2021CX01024)+1 种基金financial support from the China Postdoctoral Science Foundation(grant no.2022M710375)The technical support from Analysis&Testing Center of Beijing Institute of Technology is also appreciated.
文摘Developing artificial catalysts that mimic the functionality of enzymes and adapt to the surrounding microenvironment to achieve specific activity and selectivity is a fascinating research area yet remains a great challenge.In this work,we present a meticulously designed strategy for the successful encapsulation of ultrasmall metal clusters(MCs)within an amine-type porous organic cage(POC)through electrostatic complexation,phase transfer,and alcohol reduction processes.The amine cage showcases an intriguing and customizable feature that allows for the regulation of the surrounding microenvironment of the confined MCs through a feasible postmodifi-cation approach.This functionalization of cage skeleton further facilitates precise adjustment to the surface electronic state of Pd cluster,thereby influencing the adsorption behavior of substrate.Consequently,this controlled regulation leads to modified activity and chemoselectivity in the catalytic hydrogenation of halogenated nitrobenzene.Importantly,the investigation of the correlation between the surrounding microenvironment,substrate adsorption,and catalytic performance in the POC-immobilized MCs system has not been previously reported.We anticipate that our research will provide valuable insights in this field.
