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Linear Viscoelasticity of ABA-type Vitrimer Based on Dioxaborolane Metathesis

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Chinese Journal of Polymer Science 2024年第10期42卷 1495-1504,I0010页

作者： Shi-Long wu Huan-Huan Yang quan Chen State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of ScienceChangchun130022China University of Science and Technology of China Hefei230026China

In this study,we synthesized a series of ABA-type vitrimers by crosslinking the short A moieties of precursors with a bifunctional crosslinker and evaporating the small molecular *** vitrimer samples thus prepared exhibit linear viscoelasticity dependent on the length of A moiety as well as the content of the *** the average number of A monomers per end moiety m=1.1,the crosslinker can only extend the chain but not crosslink the *** m becomes 2.8 or higher,introducing a crosslinker first leads to the gelation,whereas excess in crosslinker molecules leads opening of the crosslinking sites and accordingly reentry into the sol ***,a further increase in the length of the A moieties increases the relaxation time much weaker than the exponential increase seen for the physically crosslinked ABAtype *** attribute this difference to the distinct relaxation mechanisms:the relaxation of the vitrimer samples is based on relatively independent exchange reactions,which contrasts with the ABA-type ionomers that relax through the collective hopping of connected ionic groups from one ion aggregate to another.

关键词： Polymer rheology Linear viscoelasticity ABA-type vitrimer Relaxation mechanism Kinetics and thermodynamics

Advances in self-assembly-based circularly polarized luminescent materials

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Science China Chemistry 2024年第10期67卷 3247-3257页

作者： Bing-Hao Liu Yang Zong Na Liu Zong-quan wu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China The School of Pharmaceutical Sciences Jilin UniversityChangchun 130021China

Circularly polarized luminescent(CPL)materials have garnered attention for their diverse applications,including three-dimensional(3D)imaging,bio-imaging,chiral sensing,and other emerging ***,the fabrication of CPL-activated materials required the use of chiral luminescent small *** introduction of the idea of self-assembly has transformed the production of CPL-activated materials,providing new and promising opportunities for their *** utilizing self-assembly,it is now feasible to produce chiral nano-assemblies with CPL activity not only from chiral molecules but also from non-chiral substances and inorganic *** addition,self-assembly routes provide a way to increase the asymmetry factor,creating possibilities for additional refinement and adjustment of CPL material *** review offers a summary of the current progress and developments in the self-assembly of small molecules and polymers,with a specific emphasis on their capacity to create or enhance CPL in different *** aim of this review is to inspire interest in optical materials that are based on the principles of self-assembly.

关键词： circularly polarized luminescence photochemistry self-assembly chiral materials

Elevational and temporal patterns of pollination success in distylous and homostylous buckwheats(Fagopyrum)in the Hengduan Mountains

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Plant Diversity 2024年第5期46卷 661-670页

作者： Ling-Yun wu Shuang-quan Huang Ze-Yu Tong Faculty of Resources and Environmental Science Hubei UniversityWuhan 430062China Institute of Evolution and Ecology School of Life SciencesCentral China Normal UniversityWuhan 430079China

Reproductive strategies of sexually dimorphic plants vary in response to the ***,we ask whether the sexual systems of Fagopyrum species(i.e.,selfing homostylous and out-crossing distylous)represent distinct adaptive strategies to increase reproductive success in changing alpine *** answer this question,we determined how spatial and temporal factors(e.g.,elevation and peak flowering time)affect reproductive success(i.e.,stigmatic pollen load)in nine wild Fagopyrum species(seven distylous and two homostylous)among 28 populations along an elevation gradient of 1299-3315 m in the Hengduan Mountains,southwestern *** also observed pollinators and conducted hundreds of hand pollinations to investigate inter/intra-morph compatibility,self-compatibility and pollen limitation in four Fagopyrum species(two distylous and two homostylous).We found that Fagopyrum species at higher elevation generally had bigger flowers and more stigmatic pollen loads;lateflowering individuals had smaller flowers and lower pollen *** pollen deposition was more variable in distylous species than in homostylous *** seed set was not pollenlimited in all species,we found that fruit set was much lower in distylous species,which rely on frequent pollinator visits,than in homostylous species capable of autonomous *** findings that pollination success increases at high elevations and decreases during the flowering season suggest that distylous and homostylous species have spatially and temporally distinct reproductive strategies related to environment-dependent pollinator activity.

关键词： Biodiversity hotspot Elevation gradient Fagopyrum Stigmatic pollen load Temporal pattern

Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

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International Journal of Mining Science and Technology 2024年第2期34卷 197-210页

作者： Jun Xu Xiaochun Xiao Lu Ma sen Luo Jiaxu Jin Baijian wu School of Mechanics and Engineering Liaoning Technical UniversityFuxin 123000China School of Civil Engineering Liaoning Technical UniversityFuxin 123000China Department of Engineering Mechanics Southeast UniversityNanjing 211189China

The damage evolution process of non-penetrating cracks often causes some unexpected engineering *** specimens containing non-penetrating crack(s)are used to study the damage evolution and characteristics under cyclic *** results show that under cyclic loading,the relationship between the number of non-penetrating crack(s)and the characteristic parameters(cyclic number,peak stress,peak strain,failure stress,and failure strain)of the pre-cracked specimens can be represented by a decreasing linear *** damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle,and the damage constitutive equation is proposed by the concept of effective ***,non-penetrating cracks are more likely to cause uneven stress distribution,damage accumulation,and local failure of *** local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the ***,the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing *** results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.

关键词： Damage characteristics Constitutive model Fissured rocks Non-penetrating crack Cyclic loading

The pseudospectrum and spectrum(in)stability of quantum corrected Schwarzschild black hole

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 55-75页

作者： Li-Ming Cao Jia-Ning Chen Liang-Bi wu Libo Xie Yu-sen Zhou School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Peng Huanwu Center for Fundamental Theory Hefei 230026China Interdisciplinary Center for Theoretical Study and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

In this study,we investigate the pseudospectrum and spectrum(in)stability of quantum corrected Schwarzschild black ***,we use the hyperboloidal framework to cast the quasinormal mode(QNM)problem into an eigenvalue problem associated with a non-selfadjoint operator,and then the spectrum and pseudospectrum are ***,the invariant subspace method is exploited to improve the computational efficiency for *** investigation into the spectrum(in)stability entails two main *** the one hand,we calculate the spectra of the quantum corrected black hole,then by the means of the migration ratio,the impact of the quantum correction effect on the Schwarzschild black hole has been *** results indicate that the so-called“migration ratio instability”will occur for small black holes with small angular momentum number *** the eikonal limit,the migration ratios remain the same for each *** the other hand,we study the spectrum(in)stability of the quantum corrected black hole by directly adding some particular perturbations into the effective potential,where perturbations are located at the event horizon and null infinity,*** are two interesting observations under the same perturbation energy ***,perturbations at infinity are more capable of generating spectrum instability than those at the event ***,we find that the peak distribution can lead to the instability of QNM spectrum more efficiently than the average distribution.

关键词： quasinormal modes pseudospectrum hyperboloidal coordinate

Auxin-brassinosteroid crosstalk:Regulating rice plant architecture and grain shape

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The Crop Journal 2024年第4期12卷 953-963页

作者： Meidi wu Jing Zhou Qian Li Dunfan quan Qingwen Wang Yong Gao Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology Yangzhou UniversityYangzhou 225009JiangsuChina Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of EducationYangzhou UniversityYangzhou 225009JiangsuChina

Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and *** review the signaltransduction of these h... 详细信息

关键词： Auxin Brassinosteroid Auxin-brassinosteroid crosstalk Plant architecture Grain shape

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)*** method proposes the utilization of airgap flux harmonics as an effective bridge between the torque design region and the torque *** illustrate the efficacy of this method,a partitioned design PMV motor is presented and compared with the initial ***,the torque design region of the rotor is artfully divided into the torque enhancement region and ripple reduction ***,the main harmonics that generate output torque are chosen and enhanced,***,the harmonics that generate torque ripple are selected and reduced based on torque harmonics ***,the functions of the partitioned PMV motor torque are assessed based on the finite element *** 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

Strip flatness prediction of cold rolling based on ensemble methods

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Journal of Iron and Steel Research International 2024年第1期31卷 237-251页

作者： wu-quan Yang Zhi-ting Zhao Liang-yu Zhu Xun-yang Gao Li Wang School of Mechanical and Power Engineering Shenyang University of Chemical TechnologyShenyang110142LiaoningChina

Aiming at the problem of insufficient prediction accuracy of strip flatness at the outlet of cold tandem rolling,the prediction performance of strip flatness based on different ensemble methods was studied and a high-precision prediction ensemble model of strip flatness at the outlet was ***,based on linear regression(LR),K nearest neighbors(KNN),support vector regression,regression trees(RT),and backpropagation neural network(BPN),bagging,boosting,and stacking ensemble methods were used for ensemble ***,three existing ensemble models,i.e.,random forest,extreme random tree(ET)and extreme gradient boosting,were used to conduct experiments and compare the *** research shows that bagging,boosting,and stacking three ensemble methods have the most significant improvement in the prediction accuracy of the regression trees model,which is increased by 5.28%,6.51%,and 5.32%,*** the same time,the stacking ensemble method improves both the simple model and the complex model,and the improvement effect on the simple base model is the greatest,which is 4.69%higher than that of the base model *** all of the ensemble models,the stacking ensemble model of level-1(ET,AdaBoost-RT,LR,BPN)paired with level-2(LR)was discovered to be the best model(EALB-LR)and can be further studied for industrial applications.

关键词： Tandem cold rolling Flatness prediction Machine learning Ensemble method

Progress in preparation of AlN-reinforced magnesium matrix composites:A review

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China Foundry 2024年第1期21卷 1-10页

作者： Lu Chen Shu-lin Lü Di-jia Zhao Wei Guo Jian-yu Li Shu-sen wu State Key Lab of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

As a ceramic material,AlN has very good thermophysical and mechanical *** addition,AlN is an effective refining agent for Mg alloys because it has a lattice constant similar to that of ***,AlN is an ideal reinforcement for magnesium matrix composites(MMCs),and is attracting increasing *** review addresses the development of preparation technologies for AlN-reinforced Mg matrix *** mainstream preparation techniques include stir casting,melt infiltration,powder metallurgy,and in-situ *** addition,the advantages and disadvantages of these techniques are analyzed in depth,and it is pointed out that the next direction for the preparation of high-performance AlN-reinforced MMCs is less aluminization and multiple technologies integration.

关键词： AlN MMCs preparation thermophysical property mechanical property