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Chien-physics-informed neural networks for solving singularly perturbed boundary-layer problems

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1467-1480页

作者： long wang Lei ZHANG Guowei HE The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

A physics-informed neural network(PINN)is a powerful tool for solving differential equations in solid and fluid ***,it suffers from singularly perturbed boundary-layer problems in which there exist sharp changes caused by a small perturbation parameter multiplying the highest-order *** this paper,we introduce Chien's composite expansion method into PINNs,and propose a novel architecture for the PINNs,namely,the Chien-PINN(C-PINN)*** novel PINN method is validated by singularly perturbed differential equations,and successfully solves the wellknown thin plate bending *** particular,no cumbersome matching conditions are needed for the C-PINN method,compared with the previous studies based on matched asymptotic expansions.

关键词： physics-informed neural network(PINN) singular perturbation boundarylayer problem composite asymptotic expansion

Electronegativity-assisted optimized electronic structure of functionalized-Pt catalysts for boosting oxygen reduction kinetics

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Rare Metals 2024年第5期43卷 1965-1976页

作者： Jin long Kai-Wen Zhuang Wei Liao Yan An Bin wang Chen-Zhong Wu Jian-xin Cao Qing wang Jun-Song Chen Qing-Mei wang Guizhou University Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Guizhou University Engineering Research Center of Effcient Utilization for Industrial Waste Guizhou UniversityGuiyang 550025China Institute of Dual-Carbon and New Energy Technology Innovation and Development of Guizhou Province Guiyang 550025China Department of Dermatology West China HospitalSichuan UniversityChengdu610041China Institute for Catalysis Hokkaido UniversitySapporo 001-0021Japan School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610106China

Opportunity to harmonize aspects of oxygen reduction reaction(ORR)performance and structure,and morphology,as well as composition,is urgent for the commercialization of proton exchange membrane fuel ***,we demonstrate the design and synthesis of a functionalized-supported-Pt catalyst(Pt@HNC)featuring a hollow nitrogen-modified dodecahedral carbon substrate obtained by a stress-induced-shrink tailoring *** as-obtained Pt@HNC catalyst possesses enhanced ORR per-formance,in particular with half-wave potential,mass activity(MA)and specific activity,which greatly exceed the commercial Pt/*** density functional theory(DFT)calculations further confirmed that the charge redistribution induced by the electronegativity differences improved the electron interaction between Pt and HNC *** optimized electronic structure of Pt weakens the reaction energy barrier on the Pt@HNC surface and adsorption of^(*)OH species,thus cooperatively improving the intrinsic activity toward ***,our work indeed provides a guide for the future design of functional nanomaterials in the field of catalysts and clean energy.

关键词： Proton exchange membrane fuel cell(PEMFC) Oxygen reduction catalysis Supported Pt-based catalyst Stability

Tortuosity regulation of two-dimensional nanofluidic films for water evaporation-induced electricity generation

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Nano Research 2024年第7期17卷 6192-6202页

作者： Zhihang Liu Chao Liu Anqi Ni Kunpeng Mao long Chen Liang Xue Jingwen Sun xin wang Pan Xiong Junwu Zhu Key Laboratory for Soft Chemistry and Functional Materials of Ministry Education School of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing 210094China

Water evaporation-induced electricity generation is a promising technology for renewable energy ***,the output power of some reported two-dimensional(2D)nanofluidic films is still restricted by the relatively weak water–solid interactions within the tortuous *** further enhance the comprehension and utilization of water–solid interactions,it is of utmost importance to conduct an in-depth investigation and propose a regulatory concept encompassing ion ***,we propose tortuosity regulation of 2D nanofluidic titanium oxide(Ti_(0.87)O_(2))films to optimize the ion transport within the interlayer nanochannel for enhanced efficiency in water evaporation-induced electricity generation for the first *** significance of tortuosity in ion transport is elucidated by designing three 2D nanofluidic films with different *** analysis and in situ Raman measurement demonstrate that low tortuosity can facilitate the formation of efficient pathways for hydrated proton transport and promote water–solid ***,devices fabricated with the optimized 2D nanofluidic films exhibited a significantly enhanced output power density of approximately 204.01μW·cm^(−2),far exceeding those prepared by the high-tortuosity 2D nanofluidic *** work highlights the significance of the construction of low tortuosity channels for 2D nanofluidic films with excellent performance.

关键词： water evaporation-induced electricity generation tortuosity ion transport two-dimensional nanofluidic films

3D-printed self-healing,biodegradable materials and their applications

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Frontiers of Mechanical Engineering 2024年第3期19卷 1-22页

作者： Yu LI Guangmeng MA Fawei GUO Chunyi LUO Han WU xin LUO MingtaoZHANG Chenyun wang Qingxin JIN Yu long School of Mechanical Engineering Guangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi UniversityNanning 530004China Institute of Laser Intelligent Manufacturing and Precision Processing School of Mechanical EngineeringGuangxi UniversityNanning 530004China College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China

3D printing is a versatile technology capable of rapidly fabricating intricate geometric structures and enhancing the performance of flexible devices in comparison to conventional fabrication ***,3D-printed devices are susceptible to failure as a result of minuscule structural impairments,thereby impacting their overall *** utilization of self-healing,biodegradable materials in 3D printing holds immense potential for increasing the longevity and safety of devices,thereby expanding the application prospects for such ***,enhancing the self-repairing capability of devices and refining the 3D printing performance of self-healing materials are still considerable challenges that need to be addressed to achieve optimal *** paper reviews recent developments in the field of advancements in 3D printing using self-healing and biodegradable ***,it investigates self-healing and biodegradable materials that are compatible with 3D printing techniques,discussing their printability,material properties,and factors that influence print ***,it explores practical applications of selfhealing and biodegradable 3D printing technology in ***,it critically offers practical perspectives on this topic.

关键词： 3D printing self-healing biodegradable soft materials covalent bonds non-covalent bonds

Semi-supervised surface defect detection of wind turbine blades with YOLOv4

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Global Energy Interconnection 2024年第3期7卷 284-292页

作者： Chao Huang Minghui Chen long wang Department of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083P.R.China Shunde Innovation School University of Science and Technology BeijingFoshan 528399P.R.China

Timely inspection of defects on the surfaces of wind turbine blades can effectively prevent unpredictable *** this end,this study proposes a semi-supervised object-detection network based on You Only Looking Once version 4(YOLOv4).A semi-supervised structure comprising a generative adversarial network(GAN)was designed to overcome the difficulty in obtaining sufficient samples and sample *** a GAN,the generator is realized by an encoder-decoder network,where the backbone of the encoder is YOLOv4 and the decoder comprises inverse convolutional *** features from the generator are passed to the defect detection *** several unlabeled images can significantly improve the generalization and recognition capabilities of defect-detection *** small-scale object detection capacity of the network can be improved by enhancing essential features in the feature map by adding the concurrent spatial and channel squeeze and excitation(scSE)attention module to the three parts of the YOLOv4 network.A balancing improvement was made to the loss function of YOLOv4 to overcome the imbalance problem of the defective *** results for both the single-and multi-category defect datasets show that the improved model can make good use of the features of the unlabeled *** accuracy of wind turbine blade defect detection also has a significant advantage over classical object detection algorithms,including faster R-CNN and DETR.

关键词： Defect detection Generative adversarial network scSE attention Semi-supervision Wind turbine

The role of a novel antibacterial substance,cyclic opine-producing Lacticaseibacillus rhamnosus LS8 in ameliorating ulcerative colitis:a fecal microbiota transplantation study

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Food Science and Human Wellness 2024年第2期13卷 778-790页

作者： Tao wang Shuang wang Shuchen Dong Ruiling wang Shuxuan wang Jie Yang xin wang xin Lü College of Food Science and Engineering Northwest Agriculture and Forestry UniversityYangling 712100China Faculty of Food Science and Engineering Kunming University of Science and TechnologyKunming 650500China School of Life Science and Technology Xinjiang UniversityUrumqi 830046China

Intestinal microbiota imbalance may worsen the progression of ulcerative colitis(UC).Lacticaseibacillus rhamnosus LS8(LR)has the potential ability to regulate microbiota through producing a novel antibacterial substance,cyclic opine:*** study aimed to investigate whether LR could ameliorate dextran sulfate sodium-induced UC in mice via modulating intestinal microbiota using fecal microbiota transplantation(FMT)*** results showed that both LR and FMT attenuated UC as evidenced by 1)alleviating disease activity index and colonic pathology;2)up-regulating MUCs and tight junction proteins;3)increasing oxidative mediators and decreasing antioxidant mediators;4)down-regulating proinflammatory cytokines and *** results were mainly attributable to the microbiota-regulating effect of LR,including increasing beneficial bacteria(like Akkermansia)and its related SCFAs,while decreasing harmful bacteria(like Proteobacteria)and its related LPS,thereby suppressing the hyperactivation of TLR4/NF-κB ***,LR can alleviate UC and is a potential dietary supplement to attenuate UC.

关键词： Gut barrier Gut microbiota Fecal microbiota transplantation Lacticaseibacillus rhamnosus Oxidative stress Ulcerative colitis

Composition operators on weighted Bergman spaces induced by doubling weights

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Science China Mathematics 2024年第7期67卷 1571-1598页

作者： xin Guo Maofa wang School of Mathematics and Statistics Wuhan UniversityWuhan430072China

Given a doubling weightωon the unit disk D,let A_(ω)^(p) be the space of all the holomorphic functions f,where∥f∥A_(ω)^(p):=(∫_(D)|f(z)|_(p)ω(z)dA(z))^(1/p)<∞.We completely characterize the topological connectedness of the set of composition operators on A_(ω)^(p).As an application,we construct an interesting example which reveals that two composition operators on A_(α)^(p) in the same path component may fail to have a compact difference and give a negative answer to the Shapiro-Sundberg question in the(standard)weighted Bergman *** addition,we completely describe the central compactness of any finite linear combinations of composition operators on A_(ω)^(p) in three terms:a Julia-Carathéodory-type function-theoretic characterization,a power-type characterization,and a Carleson-type measure-theoretic characterization.

关键词： composition operator linear combination linearly connected weighted Bergman space doubling weight

Two polyoxovanadoborates with over 100 nuclei assembled from a {V_(14)Co_(12)B_(72)} cluster

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Science China Chemistry 2024年第8期67卷 2578-2585页

作者： Shuang-Xue Wu Yu-Jiao Dong Yang Yang Chao Qin Chun-Yi Sun Wei Guan xin-long wang Zhong-Min Su Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Northeast Normal UniversityChangchun 130024China School of Chemistry and Environmental Engineering Changchun University of Science and TechnologyChangchun 130013China Key Laboratory of Advanced Materials of Tropical Island Resources Hainan UniversityHaikou 570228China

Combining theoretical prediction and experimental exploration, the first sandwich-type polyoxovanadoborate(POVB) with an odd number of nuclei, [V_(11)B_(26)O_(73)(OH)_(10)]^(8-)(1), was discovered under hydrothermal conditions. Density-functional theory(DFT)gives a rationalization for the existence of this structure and the structural feature is consistent with the {V_NB_(2N+X)}(X = 2, 4, 6, 8)general formula. Excitingly, when Co and 1,10-phenanthroline(phen) are introduced into the synthesis of vanadoborates system,a 100-nuclei [Co_6(phen)_(10)(H_(2)O)_8][V_(14)Co_(12)B_(72)O_(144)(OH)_(20)]·28H_(2)O(2) and a 102-nuclei [Co_6(phen)_(14)(H_(2)O)_(4)][V_(14)Co_(12)B_(72)O_(144)(OH)_(20)]·23H_(2)O(3) with the same core structure of [V_(14)Co_(12)B_(72)]^(12-)are obtained. The vase-shaped [V_(14)Co_(12)B_(72)] polyanion is a multilayered sandwich-type structure containing seven distinct structural layers and is the largest known POVB. Furthermore, 2demonstrates exceptional thermal and chemical stability and serves as an efficient and stable catalyst for the photoreduction of carbon dioxide.

关键词： boronate metallic materials polyoxovanadoborates density functional theory photocatalysis CO_(2)reduction

Mathematics of multi-agent learning systems at the interface of game theory and artificial intelligence

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Science China(Information Sciences) 2024年第6期67卷 445-447页

作者： long wang Feng FU xingru CHEN Center for Systems and Control College of EngineeringPeking University Center for Multi-Agent Research Institute for Artificial IntelligencePeking University Department of Mathematics Dartmouth College Department of Biomedical Data Science Geisel School of Medicine at Dartmouth School of Science Beijing University of Posts and Telecommunications

Evolutionary game theory (EGT) and artificial intelligence(AI) are two fields that,at first glance,might seem distinct,but they have notable connections and *** former focuses on the evolution of behaviors (or strategies)in a population,where individuals interact with others and update their strategies based on imitation (or social learning).

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