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Long-lived lunar volcanism sustained by precession-driven core-mantle friction

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National Science Review 2024年第2期11卷 114-123页

作者： Shuoran yu xiao xiao Shengxia Gong Nicola Tosi Jun Huang Doris Breuer Long xiao Dongdong Ni State Key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology Planetary Science Institute State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences CAS Key Laboratory of Planetary Sciences Shanghai Astronomical Observatory Institute of Planetary Research German Aerospace Centre(DLR)

Core-mantle friction induced by the precession of the Moon's spin axis is a strong heat source in the deep lunar mantle during the early phase of a satellite's evolution, but its influence on the long-term thermal evolution still remains poorly explored. Using a one-dimensional thermal evolution model, we show that core-mantle friction can sustain global-scale partial melting in the upper lunar mantle until ～3.1 Ga, thus accounting for the intense volcanic activity on the Moon before ～3.0 Ga. Besides, core-mantle friction tends to suppress the secular cooling of the lunar core and is unlikely to be an energy source for the long-lived lunar core dynamo. Our model also favours the transition of the Cassini state before the end of the lunar magma ocean phase(～4.2 Ga), which implies a decreasing lunar obliquity over time after the solidification of the lunar magma ocean. Such a trend of lunar obliquity evolution may allow volcanically released water to be buried in the lunar regolith of the polar regions. As a consequence, local water ice could be more abundant than previously thought when considering only its accumulation caused by solar wind and comet spreading.

关键词： Moon precession orbit volcanism

Strain-engineered N-polar InGaN nanowires:towards high-efficiency red LEDs on the micrometer scale

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Photonics Research 2022年第12期10卷 2809-2815页

作者： A.PANDEy J.MIN y.MALHOTRA M.REDDEPPA y.xiao y.WU Z.MI Department of Electrical Engineering and Computer Science University of MichiganAnn ArborMichigan 48109USA

The absence of efficient red-emitting micrometer-scale light emitting diodes(LEDs),i.e.,LEDs with lateral dimensions of 1μm or less is a major barrier to the adoption of microLEDs in virtual/augmented reality.The underlying challenges include the presence of extensive defects and dislocations for indium-rich InGaN quantum wells,strain-induced quantum-confined Stark effect,and etch-induced surface damage during the fabrication of quantum well microLEDs.Here,we demonstrate a new approach to achieve strong red emission(>620 nm)from dislocation-free N-polar InGaN/GaN nanowires that included an InGaN/GaN short-period superlattice underneath the active region to relax strain and incorporate more indium within the InGaN dot active region.The resulting submicrometer-scale devices show red electroluminescence dominantly from an InGaN dot active region at low-to-moderate injection currents.A peak external quantum efficiency and a wall-plug efficiency of 2.2%and1.7%were measured,respectively,which,to the best of our knowledge,are the highest values reported for a submicrometer-scale red LED.This study offers a new path to overcome the efficiency bottleneck of red-emitting microLEDs for a broad range of applications including mobile displays,wearable electronics,biomedical sensing,ultrahigh speed optical interconnect,and virtual/augmented reality.

关键词： quantum nanowires polar

Decentralized Optimal Control and Stabilization of Interconnected Systems With Asymmetric Information

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 698-707页

作者： Na Wang xiao Liang Hongdan Li xiao Lu the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266000China the School of Automation and Electrical Engineering Linyi UniversityLinyi 276000China the College of Energy Storage Technology Shandong University of Science and TechnologyQingdao 266000China

The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.

关键词： Asymmetric information decentralized control forwardbackward stochastic difference equations interconnected system stalibization

Bioinspired nanomaterials for wearable sensing and human–machine interfacing

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Nano Research 2024年第2期17卷 445-461页

作者： Vishesh Kashyap Junyi yin xiao xiao Jun Chen Department of Bioengineering University of CaliforniaLos AngelesLos AngelesCA 90095USA Department of Mechanical and Aerospace Engineering University of CaliforniaLos AngelesLos AngelesCA 90095USA

The inculcation of bioinspiration in sensing and human–machine interface(HMI)technologies can lead to distinctive characteristics such as conformability,low power consumption,high sensitivity,and unique properties like self-healing,self-cleaning,and adaptability.Both sensing and HMI are fields rife with opportunities for the application of bioinspired nanomaterials,particularly when it comes to wearable sensory systems where biocompatibility is an additional requirement.This review discusses recent development in bioinspired nanomaterials for wearable sensing and HMIs,with a specific focus on state-of-the-art bioinspired capacitive sensors,piezoresistive sensors,piezoelectric sensors,triboelectric sensors,magnetoelastic sensors,and electrochemical sensors.We also present a comprehensive overview of the challenges that have hindered the scientific advancement in academia and commercialization in the industry.

关键词： bioinspired nanomaterials human–machine interface wearable sensors wearable bioelectronics

Investigation of mechanical and electrical characteristics of selfsensing pneumatic torsional actuators

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Science China(Technological Sciences) 2024年第1期67卷 130-142页

作者： xiao Wei HU DeAn HU GuoLiang xiao yiHua Key Laboratory of Conveyance and Equipment Ministry of EducationEast China Jiaotong UniversityNanchang 330013China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha 410082China

Soft pneumatic actuators are one of the most promising actuation for soft robots,and great achievements have been obtained.But it remains challenging to endow sensing capabilities to pneumatic actuators,especially for the sensing ability originating directly from the actuator architecture.Herein,a self-sensing pneumatic torsional actuator(SPTA)is designed based on the electromagnetic induction effect and magnetically responsive materials.The SPTA can generate feedback voltage and current with the deformation,in which the sensing function comes from its inherent structure.To investigate the mechanical and electrical characteristics,an experimental platform and a finite element model are established,respectively.We find that the torsion angle and output torque increase in nonlinear with the actuating pressure.The maximum torsion angle is 66.35°,which is 84.34%of that for the actuator fabricated by pure rubber.The maximum output torque(24.9 N mm)improves by 23.19%compared with the actuator made by pure rubber.As regards the electrical characteristics,the maximum feedback voltage and current are 2.90μV and 29.50 nA when the SPTA is actuated by a pressure of−40 kPa.We also demonstrate that the relationship between the torsion angle and the magnetic flux change is approximately linear.Finally,the number of turns of wires,magnetic powders contents,and magnetic direction on the feedback voltage and current are studied.Results show that the feedback voltage and current can be enhanced by increasing the number of turns and magnetic powders contents.We envision that the SPTA would be promising for soft robots to realize their accuracy control and intelligentization.

关键词： pneumatic torsional actuators self-sensing feedback voltage finite element modeling soft robots

Evolutionary history shapes variation of wood density of tree species across the world

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Plant Diversity 2024年第3期46卷 283-293页

作者： Fangbing Li Hong Qian Jordi Sardans Dzhamal y.Amishev Zixuan Wang Changyue Zhang Tonggui Wu xiaoniu Xu xiao Tao Xingzhao Huang Anhui Province Key Laboratory of Forest Resources and Silviculture Anhui Agricultural UniversityHefei 230036China State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300China Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA CREAF Cerdanyola del VallesBarcelona 08193Spain Global Ecology Unit CREAF-CSIC-UAB CSICBellaterraBarcelona 08193Spain Key Laboratory of Ecosystem Carbon Source and Sink China Meteorological Administration(ECSS-CMA)School of Applied MeteorologyNanjing University of Information Science&Technology219 Ningliu RoadNanjing 210044China Department of Natural Resources Management Lakehead UniversityThunder BayOntario P7B 5E1Canada School of Forestry&Landscape of Architecture Anhui Agricultural UniversityHefei 230036China Research Institute of Subtropical Forestry Chinese Academy of ForestryHangzhou 311400China

The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide,we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species.We assessed phylogenetic signal in different taxonomic(e.g.,angiosperms and gymnosperms)and ecological(e.g.,tropical,temperate,and boreal)groups of tree species,explored the biogeographical and phylogenetic patterns of wood density,and quantified the relative importance of current environmental factors(e.g.,climatic and soil variables)and evolutionary history(i.e.,phylogenetic relatedness among species and lineages)in driving global wood density variation.We found that wood density displayed a significant phylogenetic signal.Wood density differed among different biomes and climatic zones,with higher mean values of wood density in relatively drier regions(highest in subtropical desert).Our study revealed that at a global scale,for angiosperms and gymnosperms combined,phylogeny and species(representing the variance explained by taxonomy and not direct explained by long-term evolution process)explained 84.3%and 7.7%of total wood density variation,respectively,whereas current environment explained 2.7%of total wood density variation when phylogeny and species were taken into account.When angiosperms and gymnosperms were considered separately,the three proportions of explained variation are,respectively,84.2%,7.5%and 6.7%for angiosperms,and 45.7%,21.3%and 18.6%for gymnosperms.Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.

关键词： Wood density Phylogeny Angiosperms Gymnosperms Climate factors Biophysical parameters

Classification of knowledge graph completeness measurement techniques

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Journal of Systems Engineering and Electronics 2024年第1期35卷 154-162页

作者： ZHANG ying xiao Gang Institute of Systems Engineering Academy of Military SciencesBeijing 100107China

At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissions and errors.Quality assessment and control,as an important means to ensure the quality of knowledge,can make the applications based on knowledge graphs more complete and more accurate by reasonably assessing the knowledge graphs and fixing and improving the quality problems at the same time.Therefore,as an indispensable part of the knowledge graph construction process,the results of quality assessment and control determine the usefulness of the knowledge graph.Among them,the assessment and enhancement of completeness,as an important part of the assessment and control phase,determine whether the knowledge graph can fully reflect objective phenomena and reveal potential connections among entities.In this paper,we review specific techniques of completeness assessment and classify completeness assessment techniques in terms of closed world assumptions,open world assumptions,and partial completeness assumptions.The purpose of this paper is to further promote the development of knowledge graph quality control and to lay the foundation for subsequent research on the completeness assessment of knowledge graphs by reviewing and classifying completeness assessment techniques.

关键词： quality assessment completeness assessment closed world assumptions open world assumption partial completeness assumption