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Recent progress in MnBi2nTe3n+1 intrinsic magnetic topological insulators: crystal growth, magnetism and chemical disorder

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National Science Review 2024年第2期11卷 65-80页

作者： Chaowei Hu Tiema Qian ni ni Department of Physics and Astronomy and California Nano Systems Institute University of California-Los Angeles

The search for magnetic topological materials has been at the forefront of condensed matter research for their potential to host exotic states such as axion insulators, magnetic Weyl semimetals, Chern insulators,etc. To date, the MnBi2nTe3n+1family is the only group of materials showcasing van der Waals-layered structures, intrinsic magnetism and non-trivial band topology without trivial bands at the Fermi level. The interplay between magnetism and band topology in this family has led to the proposal of various topological phenomena, including the quantum anomalous Hall effect, quantum spin Hall effect and quantum magnetoelectric effect. Among these, the quantum anomalous Hall effect has been experimentally observed at record-high temperatures, highlighting the unprecedented potential of this family of materials in fundamental science and technological innovation. In this paper, we provide a comprehensive review of the research progress in this intrinsic magnetic topological insulator family, with a focus on single-crystal growth, characterization of chemical disorder, manipulation of magnetism through chemical substitution and external pressure, and important questions that remain to be conclusively answered.

关键词： MnBi2Te4 magnetic topological insulator magnetism tuning antiferromagnetism ferromagnetism pressure chemical doping

Regional features of pollen R-values in China

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Science China Earth Sciences 2024年第1期67卷 295-308页

作者： Jie XIA Jian ni College of Life Sciences Zhejiang Normal UniversityJinhua 321004China Jinhua Mountain Observation and Research Station for Subtropical Forest Ecosystems Jinhua 321004China

Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary *** R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern *** study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and *** dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 *** the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific ***,pollen R-value variations across China are statistically *** two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within *** the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and ***,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased ***,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying

关键词： Pollen R-value Modern pollen-vegetation relationship Regional pattern Variability Paleovegetation reconstruction

Theoretical optimization of micropillar arrays for structurally stable bioinspired dry adhesives

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 124-129页

作者： Ke ni Zhengzhi Wang Department of Engineering Mechanics School of Civil EngineeringWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518108China

Inspired by the excellent adhesion performances of setae structure from organisms,micro/nano-pillar array has become one of the paradigms for adhesive *** micropillar arrays are composed of the resin pillars for adhesion and the substrate with different elastic modulus for *** stress singularity at the bi-material corner between the pillars and the substrate can induce the failure of the micropillar-substrate corner and further hinder the fabrication and application of micropillar arrays,yet the design for the stability of the micropillar array lacks systematical and quantitative *** this work,we develop a semi-analytical method to provide the full expressions for the stress distribution within the bi-material corner combining analytical derivations and numerical *** predictions for the stress within the singularity field can be obtained based on the full expressions of the *** good agreement between the predictions and the FEM results demonstrates the high reliability of our *** adopting the strain energy density factor approach,the stability of the pillar-substrate corner is assessed by predicting the failure at the *** the elastic mismatch between the pillar and substrate given in this paper,the stability can be improved by increasing the ratio of the shear modulus of the substrate to that of the *** study provides accurate predictions for the stress distribution at the bi-material corner and can guide the optimization of material combinations of the pillars and the substrate for more stable bioinspired dry adhesives.

关键词： Micropillar array Stability Bi-material corner Dry adhesive

Oligomerization of drug transporters:Forms,functions,and mechanisms

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Acta Pharmaceutica Sinica B 2024年第5期14卷 1924-1938页

作者： Chunxu ni Mei Hong College of Life Sciences South China Agricultural UniversityGuangzhou 510642China Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms South China Agricultural UniversityGuangzhou 510642China

Drug transporters are essential players in the transmembrane transport of a wide variety of clinical *** broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical *** our accumulating knowledge on the three-dimensional structure of drug transporters,their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification(PTM).In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins,provide clues for the development of novel drugs,and improve the therapeutic *** this review,we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies,summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins,and discuss the regulatory mechanisms of ***,we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM.

关键词： Drug development Drug transporters Oligomerization Protein expression Protein–protein interaction Regulatory mechanism Structural basis Transport function

Aubry-Mather theory for contact Hamiltonian systems Ⅲ

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Science China Mathematics 2024年第11期67卷 2541-2570页

作者： Panrui ni Lin Wang Shanghai Center for Mathematical Sciences Fudan University School of Mathematics and Statistics Beijing Institute of Technology

By exploiting the contact Hamiltonian dynamics（T*M × R,Φ_t） around the Aubry set of contact Hamiltonian systems,we provide a relation among the Mather set,the Φ_t-recurrent set,the strongly static set,the Aubry set,the Ma?é set,and the Φ_t-non-wandering ***,we consider the strongly static set,as a new flow-invariant set between the Mather set and the Aubry set in the strictly increasing *** show that this set plays an essential role in the representation of certain minimal forward weak Kolmogorov-Arnold-Moser（KAM） solutions and the existence of transitive orbits around the Aubry set.

关键词： Aubry-Mather theory weak KAM theory contact Hamiltonian systems Hamilton-Jacobi equations

Modern phenomics to empower holistic crop science, agronomy, and breeding research

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Journal of Genetics and Genomics 2024年第8期51卷 790-800页

作者： ni Jiang Xin-Guang Zhu Institute of Genetics and Developmental Biology Chinese Academy of SciencesBeijing 100101China Center of Excellence for Molecular Plant Sciences Chinese Academy of SciencesShanghai 200032China

Crop phenomics enables the collection of diverse plant traits for a large number of samples along different time scales,representing a greater data collection throughput compared with traditional *** modern crop phenomics use different sensors to collect reflective,emitted,and fluorescence signals,etc.,from plant organs at different spatial and temporal *** multi-modal,high-dimensional data not only accelerates basic research on crop physiology,genetics,and whole plant systems modeling,but also supports the optimization of field agronomic practices,internal environments of plant factories,and ultimately crop *** challenges and opportunities facing the current crop phenomics research community include developing community consensus or standards for data collection,management,sharing,and processing,developing capabilities to measure physiological parameters,and enabling farmers and breeders to effectively use phenomics in the field to directly support agricultural production.

关键词： Crop phenomics High-throughput phenotyping Traits Crop designer breeding Agronomy

Spectrum analysis of interval process model and its application in uncertain vibration analysis

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Science China(Technological Sciences) 2024年第8期67卷 2549-2564页

作者： LI JinWu JIANG Chao ni BingYu State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

In recent years, the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the “interval process model” for quantifying time-varying or dynamic uncertainties. This model employs upper and lower bounds instead of precise probability distributions to quantify uncertainty in a parameter at any given time point. It is anticipated to complement the conventional stochastic process model in the coming years owing to its relatively low dependence on experimental samples and ease of understanding for engineers. Building on our previous work, this paper proposes a spectrum analysis method to describe the frequency domain characteristics of an interval process, further strengthening the theoretical foundation of the interval process model and enhancing its applicability for complex engineering problems. In this approach, we first define the zero midpoint function interval process and its auto/cross-power spectral density(PSD) functions. We also deduce the relationship between the auto-PSD function and the auto-covariance function of the stationary zero midpoint function interval process. Next, the auto/cross-PSD function matrices of a general interval process are defined, followed by the introduction of the concepts of PSD function matrix and cross-PSD function matrix for interval process vectors. The spectrum analysis method is then applied to random vibration problems, leading to the creation of a spectrum-analysis-based interval vibration analysis method that determines the PSD function for the system displacement response under stationary interval process excitations. Finally, the effectiveness of the formulated spectrum-analysis-based interval vibration analysis approach is verified through two numerical examples.

关键词： interval process spectrum analysis power spectral density(PSD) time-varying uncertainty uncertain vibration analysis

Rethinking the Encoder-decoder Structure in Medical Image Segmentation from Releasing Decoder Structure

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Journal of Bionic Engineering 2024年第3期21卷 1511-1521页

作者： Jiajia ni Wei Mu An Pan Zhengming Chen School of Artificial Intelligence Anhui Polytechnic UniversityWuhu241000China School of Information Science and Engineering HoHai UniversityChangzhou213000China

Medical image segmentation has witnessed rapid advancements with the emergence of encoder-decoder based *** the encoder-decoder structure,the primary goal of the decoding phase is not only to restore feature map resolution,but also to mitigate the loss of feature information incurred during the encoding ***,this approach gives rise to a challenge:multiple up-sampling operations in the decoder segment result in the loss of feature *** address this challenge,we propose a novel network that removes the decoding structure to reduce feature information loss(CBL-Net).In particular,we introduce a Parallel Pooling Module(PPM)to counteract the feature information loss stemming from conventional and pooling operations during the encoding ***,we incorporate a Multiplexed Dilation Convolution(MDC)module to expand the network's receptive ***,although we have removed the decoding stage,we still need to recover the feature map ***,we introduced the Global Feature Recovery(GFR)*** uses attention mechanism for the image feature map resolution recovery,which can effectively reduce the loss of feature *** conduct extensive experimental evaluations on three publicly available medical image segmentation datasets:DRIVE,CHASEDB and MoNuSeg *** results show that our proposed network outperforms state-of-the-art methods in medical image *** addition,it achieves higher efficiency than the current network of coding and decoding structures by eliminating the decoding component.

关键词： Medical image segmentation Encoder-decoder architecture Attention mechanisms Releasing decoder architecture Neural network

Bulging Distortion of Austenitic Stainless Steel Sheet on the Partially Penetrated Side of Non-Penetration Lap Laser Welding Joint

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 286-295页

作者： Chengwu Yao Enze Liu Jiaming ni Binying nie Shanghai Key Laboratory of Materials Laser Processing and Modification School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Aerospace Precision Machinery Institute Shanghai 201600China Chemical and Biological Engineering College Yichun UniversityYichun 336000China

Non-penetration laser welding of lap joints in austenitic stainless steel sheets is commonly preferred in fields where the surface quality is of utmost ***,the application of non-penetration welded austenitic stainless steel parts is limited owing to the micro bulging distortion that occurs on the back surface of the partial penetration *** this paper,non-penetration lap laser welding experiments,were conducted on galvanized and SUS304 austenitic stainless steel plates using a fiber laser,to investigate the mechanism of bulging distortion.A comparative experiment of DC01 galvanized steel-Q235 carbon steel lap laser welding was carried out,and the deflection and distortion profile of partially penetrated side of the sheets were measured using a noncontact laser *** addition,the cold-rolled SUS304 was subjected to heat holding at different temperatures and water quenching after bending to characterize its microstructure under tensile and compressive *** results show that,during the heating stage of the thermal cycle of laser lap welding,the partial penetration side of the SUS304 steel sheet generates compressive stress,which extrudes the material in the heat-affected zone to the outside of the back of the SUS304 steel sheet,thereby forming a *** findings of these experiments can be of great value for controlling the distortion of the partial penetrated side of austenitic stainless steel sheet during laser non-penetration lap welding.

关键词： Non-penetration lap laser welding Bulging distortion Austenitic stainless steel Compressive stress Tension stress