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A new building block with intramolecular D-A character for conjugated polymers: ladder structure based on B←N unit

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Science China Chemistry 2019年第10期62卷 1387-1392页

作者： xingxin shao Chuandong Dou Jun Liu Lixiang Wang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China School of Applied Chemistry and EngineeringHefei 230026China

The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A)*** this article,we report a new strategy to develop D-A type conjugated polymers,*** fuse the D and A units into a polycyclic structure to produce a building block and then polymerize the building block with another *** develop a new building block with ladder structure based on B←N unit,B←N bridged dipyridylbenzene(BNDPB).In the skeleton of BNDPB,one diamine-substituted phenylene ring(D unit)and two B←N-linked pyridyl rings(A unit)are fused together to produce the polycyclic *** to the presence of intramolecular D-A character,the building block itself exhibits narrow bandgap of 1.74 *** conjugated polymers based on BNDPB show unique electronic structures,*** HOMOs and delocalized LUMOs,which are rarely observed for conventional D-A conjugated *** polymers exhibit smaller bandgap than that of the building block BNDPB and display near-infrared(NIR)light absorption(λabs=ca.700 nm).This study thus provides not only a new strategy to design D-A conjugated polymers but also a new kind of building block with narrow bandgap.

关键词： D-A character conjugated polymers building block ladder structure B-N unit

Topologically Correct Intersection Curves of Two Trimmed Quadrics with Tolerance Control

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Journal of Systems Science & Complexity 2024年第5期37卷 2207-2239页

作者： shao Wenbing CHEN Falai Department of Mathematics University of Science and Technology of China

Surface/surface intersection is a fundamental problem in Compute Aided Design and Geometric Modeling since it is essential to solid modeling, numerically controlled machining, feature recognition, computer animation, etc. In practical applications, quadric surfaces, which are the most basic type of surfaces, are typically bounded surfaces trimmed by a sequence of planes. In this paper,a robust algorithm is proposed for computing the intersection curve segments of two trimmed quadrics based on the parametric representation of the intersection curves of two quadrics. The proposed algorithm guarantees correct topology and ensures that the approximation errors of the end points of the intersection curve segments are less than a given tolerance. The error control is based on an effective solution to a set of polynomial inequality system using the root isolation technique. Some examples are presented to validate the robustness and effectiveness of the proposed algorithm.

关键词： Polynomial inequality system root isolation surface/surface intersection tolerance control trimmed quadrics

Pseudoeffective thresholds and cohomology of twisted symmetric tensor fields on irreducible Hermitian symmetric spaces

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Science China Mathematics 2024年第11期67卷 2433-2452页

作者： Feng shao Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

Let X be an irreducible Hermitian symmetric space of compact type(IHSS for short).In this paper,we give the irreducible decomposition of *** a by-product,we give a cohomological characterization of the rank of ***,we introduce pseudoeffective thresholds to measure the bigness of tangent bundles of smooth complex projective varieties precisely and calculate them for irreducible Hermitian symmetric spaces of compact type.

关键词： tangent bundle pseudoeffective threshold irreducible Hermitian symmetric space of compact type (IHSS) multiplicity free action

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Analysis of spatial distribution characteristics and driving factors of ethnicminority villages in China using geospatial technology and statistical models

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Journal of Mountain Science 2024年第8期21卷 2770-2789页

作者： shao Dandan ZOH Kyungjin Interdisciplinary Program in Landscape Architecture Graduate School of Environmental StudiesSeoul National UniversitySeoul 08826Korea Graduate School of Environmental Studies Seoul National UniversitySeoul 08826Korea

This study aims to reveal the spatial structural characteristics of 1,652 Ethnic-Minority Villages(EMV)in China and to analyze the mechanisms driving their spatial *** are a special type of settlement space that preserve a large number of historical traces of the ethnic culture of ancient *** are important carriers of China’s excellent traditional culture and are key to the implementation of rural revitalization *** this study,1652 EMV in China were selected as the research *** Nearest Neighbor Index,kernel density,and spatial autocorrelation index were employed to reveal the spatial structural characteristics of minority *** network models,spatial lag models,and geographical detectors were used to analyze the formation mechanism of spatial heterogeneity in *** results indicate that:(1)EMV exhibit significant spatial differentiation characterized by“single-core with multiple surrounding sub-centers,”“polarization between east and west,”“decreasing quantity from southwest to east coast to northeast to northwest,”and“large dispersion with small agglomeration.”(2)EMV are mainly distributed in areas rich in intangible cultural heritage,with high vegetation coverage and low altitude,far from central cities,and having limited arable land and an underdeveloped economy and transportation,particularly in shaded or riverbank areas.(3)Distance from the nearest river(X3),distance from central cities(X8),national intangible cultural heritage(X9),and NDVI(X10)were the main driving factors affecting the spatial distribution of EMV,whereas elevation(X1)and GDP(X5)had the weakest *** EMV are a relatively unique territorial spatial unit,the identification of their spatial heterogeneity characteristics not only deepens the research content of settlement geography,but also involves the assessment,protection,and development of Minority Villages,which is of great significance for the inheritance and utilization of excellent

关键词： Ethnic-Minority Villages Spatial structure Settlement geography Neural network model Spatial econometric model GeoDetector

Fear and delay effects on a food chain system with two kinds of different functional responses

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International Journal of Biomathematics 2024年第3期17卷 89-122页

作者： Yuanfu shao College of Science Guilin University of Technology GuilinGuangci 541004P.R.China

For food chain system with three populations,direct predation is the basic interaction between *** species often have different predation functional responses,so a food chain system with Holling-II response for middle predator and Beddinton-DeAngelis response for top predator is *** from direct predation,predator population can significantly impact the survival of prey population by inducing the prey's fear,but the impact often possesses a time *** paper is concentrated to explore how the fear and time delay affect the system stability and the species *** use of Lyapunov functional method and bifurcation theory,the positiveness and boundedness of solutions,local and global behavior of species,the system stability around the equilibrium states and various kinds of bifurcation are ***,some simulations are carried out to validate the main findings and the critical values of the bifurcation parameters of fear and conversion rate are *** is observed that fear and delay can not only stabilize,but also destabilize the system,which depends on the magnitude of the fear and *** system varies from unstable to stable due to the continuous increase of the prey's fear by middle *** fear induced by top predator or small delay of the prey's fear can stabilize the system,while they are sufficiently large,the system stability is to be ***,the conversion rate can also change the stability and even make the species to be *** rich dynamics like multiple stabilities and various types of bistability behaviors are also exhibited,which results in the convergence of the species from one stable equilibrium to another.

关键词： Fear functional response equilibrium bifurcation analysis bi-stability

Layered double hydroxides functionalization toward rechargeable batteries Author links open overlay panel

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Particuology 2024年第8期91卷 138-154页

作者： Jianxiong Gao Bowen Jin Mingfei shao State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China Renewable Energy Research Institute Quzhou Institute for Innovation in Resource Chemical EngineeringQuzhou324000China

Layered double hydroxides(LDHs),known as typical two-dimensional materials with unique physicochemical properties,are regarded as promising candidates in energy storage ***,some inherent defects,such as poor conductivity and limited active sites,hinder the further development of ***,various functionalization strategies(e.g.,intercalation of guest molecules;metal ions doping and defect introduction of host layer;exfoliation to monolayer;hybridization with functional materials;construction of hierarchical structure;interface engineering and phase transformation)have been used to modify the characteristics of LDHs,which provides guidance for designing novel *** this review,we discuss how these strategies improve the properties of LDH-based materials,which are expected to possess high electronic and ionic conductivity,high specific surface area and high mechanical and chemical stability ***,the application of LDH-based materials in advanced energy conversion and storage techniques,including metal-ions batteries,lithium-sulfur batteries and metal-air batteries,have been comprehensively summarized.

关键词： Layered double hydroxide Functionalization strategy Rechargeable battery

Aerial target threat assessment based on gated recurrent unit and self-attention mechanism

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Journal of Systems Engineering and Electronics 2024年第2期35卷 361-373页

作者： CHEN Chen QUAN Wei shao Zhuang School of Automation Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Intelligent Control and Decision of Complex Systems Beijing 100081China

Aerial threat assessment is a crucial link in modern air combat, whose result counts a great deal for commanders to make decisions. With the consideration that the existing threat assessment methods have difficulties in dealing with high dimensional time series target data, a threat assessment method based on self-attention mechanism and gated recurrent unit(SAGRU) is proposed. Firstly, a threat feature system including air combat situations and capability features is established. Moreover, a data augmentation process based on fractional Fourier transform(FRFT) is applied to extract more valuable information from time series situation features. Furthermore, aiming to capture key characteristics of battlefield evolution, a bidirectional GRU and SA mechanisms are designed for enhanced ***, after the concatenation of the processed air combat situation and capability features, the target threat level will be predicted by fully connected neural layers and the softmax classifier. Finally, in order to validate this model, an air combat dataset generated by a combat simulation system is introduced for model training and testing. The comparison experiments show the proposed model has structural rationality and can perform threat assessment faster and more accurately than the other existing models based on deep learning.

关键词： target threat assessment gated recurrent unit(GRU) self-attention(SA) fractional Fourier transform(FRFT)

BSAlign:A Library for Nucleotide Sequence Alignment

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Genomics, Proteomics & Bioinformatics 2024年第2期22卷 135-142页

作者： Haojing shao Jue Ruan Shenzhen Branch Guangdong Laboratory of Lingnan Modern AgricultureGenome Analysis Laboratory of the Ministry of Agriculture and Rural AffairsAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen 518120China

Increasing the accuracy of the nucleotide sequence alignment is an essential issue in genomics *** classic dynamic programming(DP)algorithms(e.g.,Smith–Waterman and Needleman–Wunsch)guarantee to produce the optimal result,their time complexity hinders the application of large-scale sequence *** optimization efforts that aim to accelerate the alignment process generally come from three perspectives:redesigning data structures[e.g.,diagonal or striped Single Instruction Multiple Data(SIMD)implementations],increasing the number of parallelisms in SIMD operations(e.g.,difference recurrence relation),or reducing search space(e.g.,banded DP).However,no methods combine all these three aspects to build an ultra-fast *** this study,we developed a Banded Striped Aligner(BSAlign)library that delivers accurate alignment results at an ultra-fast speed by knitting a series of novel methods together to take advantage of all of the aforementioned three perspectives with highlights such as active F-loop in striped vectorization and striped move in banded *** applied our new acceleration design on both regular and edit distance pairwise *** achieved 2-fold speed-up than other SIMD-based implementations for regular pairwise alignment,and 1.5-fold to 4-fold speed-up in edit distance-based implementations for long *** is implemented in C programing language and is available at https://***/ruanjue/bsalign.

关键词： Pairwise alignment Edit distance Striped vectorization Banded dynamic programming F evaluation

Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： shao-Wen Wei Yu-Xiao Liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic