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Dendritic tip selection during solidification of alloys:Insights from phase-field simulations

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Chinese Physics B 2024年第9期33卷 467-472页

作者： Qingjie Zhang Hui Xing Lingjie Wang Wei Zhai School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an710072China research&Development institute of Northwestern Polytechnical university in shenzhen Shenzhen 518063China

The effect of undercooling DT and the interface energy anisotropy parameter e4 on the shape of the equiaxed dendritic tip has been investigated by using a quantitative phase-field model for solidification of binary *** was found that the tip radius r increases and the tip shape amplitude coefficient A4 decreases with the increase of the fitting range for all *** dendrite tip shape selection parameter sdecreases and then stabilizes with the increase of the fitting range,and sincreases with the increase of *** relationship between sand e4 follows a power-law function sµea 4,and a is independent of DT but dependent on the fitting *** results demonstrate that the predicted sis consistent with the curve of microscopic solvability theory(MST)for e4<0.02,and sobtained from our phase-field simulations is sensitive to the undercooling when e4 is fixed.

关键词： phase-field simulations dendritic structure interface energy anisotropy tip shape selection parameter

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

MARS and RNAcmap3:The Master Database of All Possible RNA Sequences Integrated with RNAcmap for RNA Homology Search

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Genomics, Proteomics & Bioinformatics 2024年第1期22卷 143-150页

作者： Ke Chen Thomas Litfin Jaswinder Singh Jian Zhan Yaoqi Zhou institute of Systems and Physical Biology Shenzhen Bay LaboratoryShenzhen 518055China Peking university shenzhen Graduate School Shenzhen 518055China university of Science and Technology of china Hefei 230026China Suzhou institute for Advanced research University of Science and Technology of ChinaSuzhou 215123China institute for Glycomics Griffith UniversitySouthportQLD 4222Australia

sequences found in the huge,integrated database of protein sequences(Big Fantastic Database).In contrast,the existing nucleotide databases were not consolidated to facilitate wider and deeper homology ***,we built a comprehensive database by incorporating the non-coding RNA(ncRNA)sequences from RNAcentral,the transcriptome assembly and metagenome assembly from metagenomics RAST(MG-RAST),the genomic sequences from Genome Warehouse(GWH),and the genomic sequences from MGnify,in addition to the nucleotide(nt)database and its subsets in National Center of Biotechnology Information(NCBI).The resulting Master database of All possible RNA sequences(MARS)is 20-fold larger than NCBI’s nt database or 60-fold larger than *** new dataset along with a new split-search strategy allows a substantial improvement in homology search over existing state-of-the-art *** also yields more accurate and more sensitive multiple sequence alignments(MSAs)than manually curated MSAs from Rfam for the majority of structured RNAs mapped to *** results indicate that MARS coupled with the fully automatic homology search tool RNAcmap will be useful for improved structural and functional inference of ncRNAs and RNA language models based on *** is accessible at https://***/omix/release/OMIX003037,and RNAcmap3 is accessible at http://***/download/.

关键词： RNA sequence database Homology search Secondary structure MARS RNAcmap3

Metal-organic framework-based single-atom electro-/ photocatalysts: Synthesis, energy applications, and opportunities

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Carbon Energy 2024年第1期6卷 1-43页

作者： Munir Ahmad Jiahui Chen Jianwen Liu Yan Zhang Zhongxin Song Shahzad Afzal Waseem Raza Liaqat Zeb Andleeb Mehmood Arshad Hussain Jiujun Zhang Xian-Zhu Fu Jing-Li Luo shenzhen Key Laboratory of Energy Electrocatalytic Materials Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhenGuangdongChina College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhenGuangdongChina College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhenGuangdongChina Department of Environmental Engineering China Jiliang UniversityHangzhouZhejiangChina institute for Advanced Study Shenzhen UniversityShenzhenGuangdongChina School of Bioengineering Dalian University of TechnologyDalianLiaoningChina College of Materials Science and Engineering Fuzhou UniversityFuzhouFujianChina institute for Sustainable Energy Shanghai UniversityShanghaiChina

Single-atom catalysts(SACs)have gained substantial attention because of their exceptional catalytic ***,the high surface energy limits their synthesis,thus creating significant challenges for further *** the last few years,metal–organic frameworks(MOFs)have received significant consideration as ideal candidates for synthesizing SACs due to their tailorable chemistry,tunable morphologies,high porosity,and chemical/thermal *** this perspective,this review thoroughly summarizes the previously reported methods and possible future approaches for constructing MOF-based(MOF-derived-supported and MOF-supported)***,MOF-based SAC's identification techniques are briefly assessed to understand their coordination environments,local electronic structures,spatial distributions,and catalytic/electrochemical reaction *** review systematically highlights several photocatalytic and electrocatalytic applications of MOF-based SACs for energy conversion and storage,including hydrogen evolution reactions,oxygen evolution reactions,O_(2)/CO_(2)/N_(2) reduction reactions,fuel cells,and rechargeable *** light is also shed on the future development of this highly exciting field by highlighting the advantages and limitations of MOF-based SACs.

关键词： carbon energy generation MOF-derived-supported MOF-supported single atoms

High-Performance Recyclable Furan-based Epoxy Resin and Its Carbon Fiber Composites with Dense Hydrogen Bonding

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Chinese Journal of Polymer Science 2024年第1期42卷 73-86,I0008页

作者： Chang-Bo Zhao Lu-Kun Feng Hui Xie Ming-Liang Wang Bing Guo Zhi-Yong Xue Cai-Zhen Zhu Jian Xu Advanced Materials research institute North China Electric Power UniversityBejing 102206China institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Chengdu institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China School of Science and shenzhen Key Laboratory of Flexible Printed Electronics Technology and Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive ApplicationHarbin Institute of TechnologyShenzhen 518055China

The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of *** the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine *** study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.

关键词： Furan Hydrogen bond network Dynamic Schiff base Carbon fiber composites Recycling

Functional Optical Fiber Sensors Detecting Imperceptible Physical/Chemical Changes for Smart Batteries

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Nano-Micro Letters 2024年第8期16卷 268-308页

作者： Yiding Li Li Wang Youzhi Song Wenwei Wang Cheng Lin Xiangming He institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084People’s Republic of China National Engineering research Center of Electric Vehicles Beijing Institute of Technology(BIT)Beijing 100081People’s Republic of China shenzhen Automotive research institute of BIT(shenzhen research institute of National Engineering research Center of Electric Vehicles) Shenzhen 518118People’s Republic of China

The battery technology progress has been a contradictory process in which performance improvement and hidden risks *** the battery is still a“black box”,thus requiring a deep understanding of its internal *** battery should“sense its internal physical/chemical conditions”,which puts strict requirements on embedded sensing *** paper summarizes the application of advanced optical fiber sensors in lithium-ion batteries and energy storage technologies that may be mass deployed,focuses on the insights of advanced optical fiber sensors into the processes of one-dimensional nano-micro-level battery material structural phase transition,electrolyte degradation,electrode-electrolyte interface dynamics to three-dimensional macro-safety *** paper contributes to understanding how to use optical fiber sensors to achieve“real”and“embedded”*** the inherent advantages of the advanced optical fiber sensor,it helps clarify the battery internal state and reaction mechanism,aiding in the establishment of more detailed *** advancements can promote the development of smart batteries,with significant importance lying in essentially promoting the improvement of system ***,with the help of smart batteries in the future,the importance of consistency can be weakened or even *** application of advanced optical fiber sensors helps comprehensively improve the battery quality,reliability,and life.

关键词： Smart battery Advanced embedded optical fiber sensor Battery internal physical/chemical state Quality-reliability-life characteristic

Resonance mechanism of flapping wing based on fluid structure interaction simulation

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Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing YANG Yuanbo DONG Dong XUE National Key Laboratory of Science and Technology on Aerodynamic Design and research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China research&Development institute of Northwestern Polytechnical university in shenzhen Shenzhen 518063China Yangtze River Delta research institute of Northwestern Polytechnical university Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism Aerodynamic performance

Multi-scale data joint inversion of minerals and porosity in altered igneous reservoirs—A case study in the South china Sea

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Petroleum Science 2024年第1期21卷 206-220页

作者： Xin-Ru Wang Bao-Zhi Pan Yu-Hang Guo Qing-Hui Wang Yao Guan College of Geo-exploration Science and Technology Jilin UniversityChangchun130046JilinChina research institute CNOOC Ltd.-ShenzhenShenzhen518000GuangdongChina

There are abundant igneous gas reservoirs in the South china Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir ***,affected by the diverse lithology,complicated mineral and widespread alteration,conventional logging lithology classification and mineral inversion become considerably *** the same time,owing to the limitation of the wireline log response equation,the quantity and accuracy of minerals can hardly meet the exploration requirements of igneous *** overcome those issues,this study takes the South china Sea as an example,and combines multi-scale data such as micro rock slices,petrophysical experiments,wireline log and element cutting log to establish a set of joint inversion methods for minerals and porosity of altered igneous ***,we define the lithology and mineral characteristics through core slices and mineral data,and establish an igneous multi-mineral volumetric *** we determine element cutting log correction method based on core element data,and combine wireline log and corrected element cutting log to perform the lithology classification and joint inversion of minerals and ***,it is always difficult to determine the elemental eigenvalues of different minerals in *** paper uses multiple linear regression methods to solve this ***,an integrated inversion technique for altered igneous formations was *** results show that the corrected element cutting log are in good agreement with the core element data,and the mineral and porosity results obtained from the joint inversion based on the wireline log and corrected element cutting log are also in good agreement with the core data from X-ray *** results demonstrate that the inversion technique is applicable and this study provides a new direction for the mineral inversion research of altered igneous formation

关键词： Joint inversion Altered igneous rock Element correction method Lithology identification Multi mineral volume model

Tailoring sulfur-doped and nitrogen-defective carbon nitride nanosheets for efficient photo-controlled radical polymerizations

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Science china Chemistry 2024年第7期67卷 2325-2334页

作者： Xue Li Meng Kai Xu Yuan Huang Tao Cai Key Laboratory of Biomedical Polymers of Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072China Wuhan university shenzhen research institute Shenzhen 518057China

Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy ***,sulfur-doped and nitrogen-defective g-C_(3)N_(4)(n-SC_(3)N_(x))nanosheets were designed and elaborately *** resultant n-SC_(3)N_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface *** photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed *** to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)N_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)N_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)N_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.

关键词： graphitic carbon nitride nitrogen defects sulfur dopants PET-RAFT polymerization recyclability