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Weak type(1, 1) of the Riesz transform on some direct product manifolds with exponential volume growth

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Science China Mathematics 2024年第7期67卷 1599-1622页

作者： Hong-quan li Jie-Xiang Zhu School of Mathematical Sciences Fudan UniversityShanghai200433China Center for Applied Mathematics Tianjin UniversityTianjin300072China

In this paper, we are concerned with the Riesz transform on the direct product manifold H^(n)× M,where H^(n) is the n-dimensional real hyperbolic space, and M is a connected complete non-compact Riemannian manifold satisfying the volume doubling property and generalized Gaussian or sub-Gaussian upper estimates for the heat kernel. We establish its weak type(1, 1) property. In addition, we obtain the weak type(1, 1) of the heat maximal operator in the same setting. Our arguments also work for a large class of direct product manifolds with exponential volume growth. Particularly, we provide a simpler proof of weak type(1, 1) boundedness of some operators considered in the work of li et al.(2016).

关键词： Riesz transform heat kernel direct product real hyperbolic space

Rheological Behaviors of Polymers with Nanoparticles Tethered at Each End

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Chinese Journal of Polymer Science 2024年第3期42卷 400-406,I0009页

作者： Song-Qi Zhang Wen-Qing Wang Jia-Ping lin li-quan Wang Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from-1/2 to-3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology.

关键词： Polymer rheology Modulus Viscosity Molecular dynamics

Sliced Average Variance Estimation for Tensor Data

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 630-655页

作者： Chuan-quan li Pei-wen XIAO Chao YING Xiao-hui liU School of Statistics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China Biostatistics and Medical Informatics University of Wisconsin MadisonMadison 53726USA

Tensor data have been widely used in many fields,e.g.,modern biomedical imaging,chemometrics,and economics,but often suffer from some common issues as in high dimensional statistics.How to find their low-dimensional latent structure has been of great interest for statisticians.To this end,we develop two efficient tensor sufficient dimension reduction methods based on the sliced average variance estimation(SAVE)to estimate the corresponding dimension reduction subspaces.The first one,entitled tensor sliced average variance estimation(TSAVE),works well when the response is discrete or takes finite values,but is not■consistent for continuous response;the second one,named bias-correction tensor sliced average variance estimation(CTSAVE),is a de-biased version of the TSAVE method.The asymptotic properties of both methods are derived under mild conditions.Simulations and real data examples are also provided to show the superiority of the efficiency of the developed methods.

关键词： tensor data sliced average variance estimation sufficient dimension reduction central subspace

Airgap-harmonic-oriented Partitioned Design Method of PMV Motor with Improved Torque Performances

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 43-50页

作者： Zhaopeng Wu li quan Zixuan Xiang Deyang Fan Tengguang Wang Xiaoyong Zhu the School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China IEEE

Here,we introduce a partitioned design method that is oriented toward airgap harmonic for permanent magnet vernier(PMV)motors.The method proposes the utilization of airgap flux harmonics as an effective bridge between the torque design region and the torque performances.To illustrate the efficacy of this method,a partitioned design PMV motor is presented and compared with the initial design.Firstly,the torque design region of the rotor is artfully divided into the torque enhancement region and ripple reduction region.Meanwhile,the main harmonics that generate output torque are chosen and enhanced,optimization.Moreover,the harmonics that generate torque ripple are selected and reduced based on torque harmonics optimization.Finally,the functions of the partitioned PMV motor torque are assessed based on the finite element method.By the purposeful design of these two regions,the output torque is strengthened while torque ripple is inhibited effectively,verifying the effectiveness and reasonability of the proposed design method.

关键词： Permanent magnet vernier(PMV)motor Airgap flux harmonic Partitioned design Low torque ripple

Mammals of Gaoligong Mountain in China:Diversity,distribution,and conservation

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Zoological Research(Diversity and Conservation) 2024年第1期1卷 3-19页

作者： quan li Xue-You li Wen-Qiang Hu Wen-Yu Song Shui-Wang He Hong-Jiao Wang Zhe-Chang Hu Meng-Cheng li Kenneth Otieno Onditi Zhong-Zheng Chen Chang-Zhe Pu Yun Xiong Cai-Hong Rao Fu-You Zhang Chang-Sheng Zuo Xue-Long Jiang State Key Laboratory of Genetic Resources and Evolution&Yunnan Key Laboratory of Biodiversity and Ecological Conservation of Gaoligong Mountain Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China Gaoligong Mountain Forest Ecosystem Observation and Research Station of Yunnan Province&Dulongjiang Forest Ecosystem Research Station KunmingYunnan 650223China University of Chinese Academy of Sciences Beijing 101408China Vector Laboratory Institute of Pathogens and VectorsYunnan Provincial Key Laboratory for Zoonosis Control and PreventionDali UniversityDaliYunnan 671000China School of Ecology and Environment Anhui Normal UniversityWuhuAnhui 241002China Gongshan Administrative Sub-Bureau of Gaoligongshan National Nature Reserve NujiangYunnan 673500China Fugong Administrative Sub-Bureau of Gaoligongshan National Nature Reserve NujiangYunnan 673400China Baoshan Administrative Bureau of Gaoligongshan National Nature Reserve BaoshanYunnan 678000China Administrative Bureau of Tongbiguan Provincial Nature Reserve DehongYunnan 679300China

Gaoligong Mountain(hereafter,GLGM)is located at the intersection of Myanmar and China’s Yunnan Province and Xizang Zizhiqu,and spans three globally significant biodiversity hotspots:the Himalayas,Indo-Burma,and the Mountains of Southwest China.Although surveys of mammals in this ecologically important region have a long history,there is no comprehensive systematic checklist and distribution account of the mammals of GLGM.Here,we compiled a mammal species checklist of GLGM based on thorough field investigations and literature reviews.We also examined specimen collections and applied camera trapping surveys to explore the region’s mammal diversity and distribution patterns.We recorded 212 mammal species in nine orders,33 families,and 119 genera,which accounts for 30.5%of China’s mammal species,and a high proportion of nationally protected(50)and globally threatened(29)species.Mammal species richness showed a symmetrical unimodal curve along the elevation gradient,peaking at intermediate elevations(2000 to 2500 m above sea level(asl)),and increasing generally from south to north,slightly higher in the east slope than in the west.Cluster analysis and non-metric multidimensional scaling revealed three distinct elevational assemblages(3500 m asl)and significant south-to-north variation,but no substantial differences between the east and west slopes.The GLGM present a unique conservation value due to the high proportions of rare and endangered mammal species,complex faunal composition,high endemism,and being the distribution boundary for many species.This study is an important phased account of mammal diversity in GLGM and makes a prospect for future research.

关键词： Biodiversity hotspot Eastern Himalaya Gaoligong Mountain Endemism Mammal conservation Hengduan Mountains

Urea-induced interfacial engineering enabling highly reversible aqueous zinc-ion battery

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Rare Metals 2024年第4期43卷 1599-1609页

作者： Bin-Rui Xu quan-An li Yong liu Guang-Bin Wang Zi-He Zhang Feng-Zhang Ren School of Material Science and Engineering Henan University of Science and Technology School of Information Engineering Henan University of Science and Technology Longmen Laboratory Provincial and Ministerial Co-Construction of Collaborative Innovation Center for Non-Ferrous Metal New Materials and Advanced Processing Technology

Aqueous zinc-ion batteries（AZIBs） have been regarded as prospective rechargeable energy storage devices because of the high theoretical capacity and low redox potential of Zn metal.However,the uncontrollable formation of dendrites and the water-induced side reactions at the Zn/electrolyte interface,and the poor reversibility under a high current density(> 2 mA·cm-2) and large area capacity(>2 mAh·cm-2) still limit the practical applications of AZIBs.Therefore,a strategy that can overcome these difficulties is urgently needed.Here,we introduce an environmentally friendly and low-cost additive,namely urea,to the electrolyte of AZIBs to induce uniform Zn deposition and suppress the side reactions.Measurements of the adsorption behavior,electrochemical characterization,and observations of the morphology revealed the interfacial modification induced by urea on the Zn/electrolyte interface,demonstrating its huge potential in AZIBs.Consequently,the long-term cycling stability（over2100 h） of a Zn/Zn symmetric cell under a high current density of 5 mA·cm-2and a capacity of 5 mAh·cm-2was achieved with a 1 mol·L-1ZnSO4electrolyte with the urea additive.Additionally,the assembled Zn/NH4V4O10full cell with urea exhibited excellent cycling performance and an outstanding average Coulombic efficiency of 99.98%.These results indicate that this is a low-cost and effective additive strategy for realizing highly reversible AZIBs.

关键词： Zn anode Urea additive Interface engineering Dendrite growth Side reaction

Biological scaffold as potential platforms for stem cells:Current development and applications in wound healing

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World Journal of Stem Cells 2024年第4期16卷 334-352页

作者： Jie-Yu Xiang lin Kang Zi-Ming li Song-Lu Tseng li-quan Wang Tian-Hao li Zhu-Jun li Jiu-Zuo Huang Nan-Ze Yu Xiao Long Department of Plastic and Reconstructive Surgery Peking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Biomedical Engineering Facility Institute of Clinical MedicinePeking Union Medical College HospitalChinese Academy of Medical SciencesBeijing 100021China

Wound repair is a complex challenge for both clinical practitioners and researchers.Conventional approaches for wound repair have several limitations.Stem cell-based therapy has emerged as a novel strategy to address this issue,exhibiting significant potential for enhancing wound healing rates,improving wound quality,and promoting skin regeneration.However,the use of stem cells in skin regeneration presents several challenges.Recently,stem cells and biomaterials have been identified as crucial components of the wound-healing process.Combination therapy involving the development of biocompatible scaffolds,accompanying cells,multiple biological factors,and structures resembling the natural extracellular matrix(ECM)has gained considerable attention.Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells,providing them with an environment conducive to growth,similar to that of the ECM.These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing.This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing,emphasizing their capacity to facilitate stem cell adhesion,proliferation,differentiation,and paracrine functions.Additionally,we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

关键词： Stem-cell-based therapy Biological scaffolds Wound healing Extracellular matrix mimicry Cellular activities enhancement Scaffold characteristics

Copper nanowires decorated with TiO_(2−x) from MXene for enhanced electrocatalytic nitrogen oxidation into nitrate under vacuum assistance

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Nano Research 2023年第10期16卷 12357-12362页

作者： quan li Zhengting Xiao Weina Jia Qin li Xianguo li Wentai Wang Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationCollege of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101China Queensland Micro-and Nanotechnology Centre School of Engineering and Built EnvironmentGriffith University Nathan CampusBrisbaneQLD 4111Australia

The green synthesis of nitrate(NO_(3)^(−))via electrocatalytic nitrogen oxidation reaction(NOR)is a promising strategy for artificial nitrogen fixation,which shows great advantages than traditional nitrate synthesis based on Haber–Bosch and Ostwald processes.But the poor N_(2)absorption,high bond energy of N≡N(941 kJ·mol^(−1)),and competing multi-electron-transfer oxygen evolution reaction(OER)limit the activity and selectivity.Herein,we fabricated MXene-derived irregular TiO_(2)−x nanoparticles anchored Cu nanowires(Cu-NWs)electrode for efficient electrocatalytic nitrogen oxidation,which exhibits a NO_(3)−yield of 62.50μg·h^(−1)·mgcat^(−1)and a Faradaic efficiency(FE)of 22.04%,and a significantly enhanced NO_(3)−yield of 92.63μg·h^(−1)·mgcat^(−1),and a FE of 40.58%under vacuum assistance.The TiO_(2)−x/Cu-NWs electrode also shows excellent reproducibility and stability under optimal experimental conditions.Moreover,a Zn-N_(2)reaction device was assembled with TiO_(2−x)/Cu-NWs as an anode and Zn plate as a cathode,obtaining an extremely high NO_(3)−yield of 156.25μg·h^(−1)·mgcat^(−1).The Zn-nitrate battery shows an open circuit voltage(OCV)of 1.35 V.This work provides novel strategies for enhancing the performance of ambient N_(2)oxidation to obtain higher NO_(3)^(−)yield.

关键词： nitrogen oxidation nitrate production electrocatalysis Zn-N_(2)system Zn-nitrate battery vacuum assistance

Effect of the anionic composition of sulfolane based electrolytes on the performances of lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第8期95卷 231-240页

作者： Elena V.Karaseva Elena V.Kuzmina Bo-quan li Qiang Zhang Vladimir S.Kolosnitsyn Ufa Institute of Chemistry of the Ufa Federal Research Centre of the Russian Academy of Science Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical Engineering Tsinghua University

In lithium-sulfur batteries,cell design,specifically electrolyte design,has a key impact on the battery performance.The effect of lithium salt anion donor number（DN）(DN[PF6]-=2.5,DN[N（SO2CF3）2]-=5.4,DN[ClO4]-=8.4,DN[SO3CF3]-=16.9,and DN[NO3]-=21.1) on the patterns of lithium-sulfur batteries and lithium metal electrode performances with sulfola ne-based electrolytes is investigated.An increase in DN of lithium salt anions leads to an increase in the depth and rate of electrochemical reduction of sulfur and long-chain lithium polysulfides and to a decrease in those for medium-and short-chain lithium polysulfides.DN of lithium salt anions has weak effect on the discharge capacity of lithium-sulfur batteries and the Coulomb efficiency during cycling,with the exception of liSO3CF3and liNO3.An increase in DN of lithium salt anions leads to an increase in the cycling duration of lithium metal anodes and to a decrease in the presence of lithium polysulfides.In sulfolane solutions of liNO3and liSO3CF3,lithium polysulfides do not affect the cycling duration of lithium metal anodes.

关键词： Donor number Electrolyte lithium metal electrode lithium polysulfide lithium salt lithium-sulfur battery Sulfolane