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A Study on the Impact of Chemical Structure on the Evolution of Aggregate Structure in Fiber-shaped High Density Polyethylene Vitrimer

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chinese Journal of Polymer Science 2024年第10期42卷 1557-1565,I0013页

作者： Bing Wang Yuan-chu Gao Hai Wang Hui Niu State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian116024China

Vitrimers have emerged as a prominent research area in the field of polymer *** of the studies have focused on synthesizing polymers with versatile dynamic crosslinking structures,while the impact of chemical structure on aggregate structure of vitrimers,particularly during polymer processing,remains insufficiently *** present study employed commercial maleic anhydride-grafted-high density polyethylene(M-g-HDPE)as the matrix and hexanediol as the crosslinker to facilely obtain fiber-shaped HDPE vitrimers through a reaction extrusion and post-drawing *** chemical structure characterization,morphology observation,thermal and mechanical properties investigation,as well as aggregate structure analysis,this work revealed the influence of dynamic bonds on the formation of aggregate structures during fiber-shaped vitrimers processing.A small amount of dynamic bonds in HDPE restricts the motion of PE chain during melt-extruding and post-drawing,resulting in a lower orientation of the PE ***,lamellar growth and fibril formation during post-drawing at high temperature are enhanced to some extent due to the competition between dynamic bond and chain *** uneven morphology of fibershaped HDPE vitrimers can be attributed to the stronger elastic effect brought by dynamic bonding,which plays a more dominant role in determining the mechanical properties of fiber-shaped vitrimers compared to aggregate *** Vitrimers have emerged as a prominent research area in the field of polymer *** of the studies have focused on synthesizing polymers with versatile dynamic crosslinking structures,while the impact of chemical structure on aggregate structure of vitrimers,particularly during polymer processing,remains insufficiently *** present study employed commercial maleic anhydride-grafted-high density polyethylene(M-g-HDPE)as the matrix and hexanediol as the crosslinker to facilely obtain fiber-shap

关键词： High density polyethylene vitrimer Fiber-shaped Aggregate structures Transesterification reaction

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Surface chemical microenvironment engineering of catalysts by organic molecules for boosting electrocatalytic reaction

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chinese Chemical Letters 2024年第8期35卷 15-24页

作者： Xianxu chu Lu Wang Junru Li Hui Xu Henan Key Laboratory of Biomolecular Recognition and Sensing College of Chemistry and Chemical EngineeringShangqiu Normal UniversityShangqiu 476000China Key Laboratory of Advanced Catalytic Materials and Technology Advanced Catalysis and Green Manufacturing Collaborative Innovation CenterChangzhou UniversityChangzhou 213164China

Electrocatalysis is a surface-sensitive process,in which the catalytic activity of electrocatalyst highly re-lates to the surface adsorption/desorption behaviors of the reactants/intermediates/products on the cat-alytically active *** chemical microenvironment engineering via organic molecules functional-ization is a promising strategy to tune the electrocatalytic activity since it can well modify the elec-trode/electrolyte interface and alter the reaction *** this review,we summarize the recent progress of surface microenvironment engineering of electrocatalysts induced by organic molecules func-tionalization,with the special focus on the organic molecule-assisted growth mechanism and unique electronic *** importantly,the applications of organic molecule functionalized catalysts in var-ious electrocatalytic reactions are also systematically summarized,along with a deep discussion on the conclusion and *** work will open a new avenue for the construction and modification of advanced electrocatalysts based on organic molecule-mediated interface engineering.

关键词： Chemical microenvironment engineering Organic molecules Electrocatalysis Functionalization Interface

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Structural characterization of three acidic polysaccharides from Opuntia dillenii *** and their protective effect against hydrogen peroxide-induced oxidative stress in Huh-7 cells

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Food Science and Human Wellness 2024年第4期13卷 1929-1942页

作者： Rui Liu Fangxin chu Zheng Yan Hanqing Chen School of Food and Biological Engineering Hefei University of TechnologyHefei 230601China Engineering Research Center of Bio-Process Ministry of EducationHefei University of TechnologyHefei 230601China

Three novel acidic polysaccharide fractions(OFPP-1,OFPP-2,OFPP-3)with different m olecular weights(803.7,555.1 and 414.5 k Da)were isolated from the peeled Opuntia dillenii *** by alkali-extraction,graded alcohol precipitation and column *** analysis indicated that OFPPs were pectic polysaccharides consisting of rhamnose,arabinose and galactose *** backbone of OFPP-1 consisted of a repeating unit→6-α-D-Galp A-(1→2)-α-L-Rhap-(1→with T-α-D-Galp A-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→,T-β-D-Xylp-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→or T-α-D-Galp A-(1→3)-α-L-Araf-(1→as the side *** backbone of OFPP-2 consisted of a disaccharide repeating unit→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→with T-β-L-Araf-(1→as the branches substituted at the O-4 position of→2,4)-α-LRhap-(1→.Whereas the backbone of OFPP-3 was→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-β-L-Araf-(1→or→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→,which was branched at the O-4 position of→2,4)-α-L-Rhap-(1→.Moreover,these three polysaccharide fractions could protect Huh-7 cells against H2O2-induced oxidative stress to different extents by decreasing the MDA content and increasing the SOD,CAT,GSH-Px activities and the GSH level in the Huh-7 *** results suggest that OFPPs have the potential to be used as natural antioxidants.

关键词： Opuntia dillenii Haw.fruits Polysaccharide Alkali extraction Structural characterization Oxidative stress

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Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

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Science china Chemistry 2024年第5期67卷 1707-1714页

作者： Ying Zhang Zhuohang Li Wenyu Du Kai Chen Ke chu School of Materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production.

关键词： electrochemical nitrite-to-ammonia conversion frustrated Lewis acid-base pairs(FLPs) in situ spectroscopy theoretical computations

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MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 395-404页

作者： Ge chu Chaohui Wang Zhewei Yang Lin Qin Xin Fan College of Materials Science&Engineering Guilin University of TechnologyGuilin 541004China Institute of Energy Innovation College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl *** as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion ***,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

关键词： metal-organic framework porous graphitic carbon optimized plateau capacity kinetic analysis lithium-ion capacitor

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Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2305-2338页

作者： Chenxi Xiu Xihua chu School of Civil Engineering Chongqing Jiaotong UniversityChongqing400074China School of Civil Engineering Wuhan UniversityWuhan430072China

This paper presents a micromechanics-based Cosserat continuum model for microstructured granular *** utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural *** microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized ***,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield *** investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)*** demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain *** study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials ***,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic *** parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element.

关键词： Granular materials micromechanics Cosserat elastoplastic model microstructures failure behaviors

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Perception field based imitation learning for unlabeled multi-agent pathfinding

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Science china(Information Sciences) 2024年第5期67卷 115-135页

作者： Wenjie chu Ailun YU Wei ZHANG Haiyan ZHAO Zhi JIN School of Computer Science Peking University Key Laboratory of High-Confidence Software Technologies (Peking University) Ministry of Education

This paper proposes an imitation learning method to learn a universal agent policy for unlabeled multi-agent pathfinding(unlabeled MAPF) in grid environments. The method transforms the unlabeled MAPF problem into a series of temporal-independent homogeneous classification problems for each *** on this transformation, a neural network is designed to imitate a distance-optimal expert *** neural network consists of two successive modules: perception field learner and field integrating *** former refines and encodes the current system state into a perception field for each agent by combining a set of learnable field-generating functions. The latter takes an agent's perception field as input and decides the agent's next action based on a triplet cross-attention mechanism. We evaluate our method on a diverse set of unlabeled MAPF tasks. Compared with state-of-the-art counterparts, the experimental results manifest the superiority of the proposed method in both generalization ability and scalability.

关键词： unlabeled multi-agent pathfinding perception field triplet cross-attention multi-agent imitation learning learning-based planning

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Intuitive Human-Robot-Environment Interaction With EMG Signals:A Review

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1075-1091页

作者： Dezhen Xiong Daohui Zhang Yaqi chu Yiwen Zhao Xingang Zhao State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016 Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169 University of chinese Academy of Sciences Beijing 100049China

A long history has passed since electromyography(EMG)signals have been explored in human-centered robots for intuitive ***,it still has a gap between scientific research and real-life *** studies mainly focused on EMG decoding algorithms,leaving a dynamic relationship between the human,robot,and uncertain environment in real-life scenarios seldomly *** fill this gap,this paper presents a comprehensive review of EMG-based techniques in human-robot-environment interaction(HREI)*** general processing framework is summarized,and three interaction paradigms,including direct control,sensory feedback,and partial autonomous control,are ***-based intention decoding is treated as a module of the proposed *** key issues involving precision,stability,user attention,compliance,and environmental awareness in this field are *** important directions,including EMG decomposition,robust algorithms,HREI dataset,proprioception feedback,reinforcement learning,and embodied intelligence,are proposed to pave the way for future *** the best of what we know,this is the first time that a review of EMG-based methods in the HREI system is *** provides a novel and broader perspective to improve the practicability of current myoelectric interaction systems,in which factors in human-robot interaction,robot-environment interaction,and state perception by human sensations are considered,which has never been done by previous studies.

关键词： robot summarized Robot

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Transient state analysis of a rub-impact rotor system during maneuvering flight

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chinese Journal of Aeronautics 2024年第7期37卷 236-251页

作者： Jun WANG Yunfei LIU Zhaoye QIN Liang MA Fulei chu Beijing Key Laboratory of Health Monitoring and Self-Recovery for High-End Machinery Equipment Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China College of Aeronautical Engineering Civil Aviation University of ChinaTianjin 300300China

Maneuvering flight substantially affects the dynamic behavior of rotors;particularly,such flight may cause rubbing between a rotor and stator,which is one of the most serious damages in aircraft *** this paper,a nonlinear dynamic model for describing the dynamic characteristics of a rub-impact rotor system during maneuvering flight is established based on the Lagrange ***,numerical simulations employing the Newmark method are performed,delving into the detailed discussion of the influence of parameters such as rotational speed and maneuvering flight on the transient and steady-state responses of the rotor *** effect mechanism of maneuver load and its coupling with rub impact is *** results show that the impact response induced by maneuvering flight is more obvious in the subcritical state than in the supercritical *** additional stiffness and damping are also induced;in particular,the additional damping has a coupling ***,the rub impact imposes an additional constraint on the rotor system,thereby weakening the influence of the maneuver load and becoming the major factor that determines the dynamic behavior of the rotor system at high speeds.

关键词： Maneuvering flight Rub impact Rotor system Dynamic response Impact response

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Developing risk models and subtypes of autophagy-associated LncRNAs for enhanced prognostic prediction and precision in therapeutic approaches for liver cancer patients

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Oncology Research 2024年第4期32卷 703-716页

作者： LU ZHANG JINGUO chu YUSHAN YU Department of General Practice The First Affiliated Hospital of Ningbo UniversityNingboChina

Background:Limited research has been conducted on the influence of autophagy-associated long non-coding RNAs(ARLncRNAs)on the prognosis of hepatocellular carcinoma(HCC).Methods:We analyzed 371 HCC samples from TCGA,identifying expression networks of ARLncRNAs using autophagy-related *** for prognostically relevant ARLncRNAs involved univariate Cox regression,Lasso regression,and multivariate Cox regression.A Nomogram was further employed to assess the reliability of Riskscore,calculated from the signatures of screened ARLncRNAs,in predicting ***,we compared drug sensitivities in patient groups with differing risk levels and investigated potential biological pathways through enrichment analysis,using consensus clustering to identify subgroups related to ***:The screening process identified 27 ARLncRNAs,with 13 being associated with HCC ***,a set of signatures comprising 8 ARLncRNAs was successfully constructed as independent prognostic factors for *** in the high-risk group showed very poor prognoses in most clinical *** Riskscore was closely related to immune cell scores,such as macrophages,and the DEGs between different groups were implicated in metabolism,cell cycle,and mitotic ***,high-risk group patients demonstrated a significantly lower IC50 for Paclitaxel,suggesting that Paclitaxel could be an ideal treatment for those at elevated risk for *** further identified C2 as the Paclitaxel subtype,where patients exhibited higher Riskscores,reduced survival rates,and more severe clinical ***:The 8 signatures based on ARLncRNAs present novel targets for prognostic prediction in *** drug candidate Paclitaxel may effectively treat HCC by impacting ARLncRNAs *** the identification of ARLncRNAsrelated isoforms,these results provide valuable insights for clinical exploration of autophagy mechanisms in HCC pathogenesis and offer potential av

关键词： Autophagy Hepatocellular carcinoma(HCC) Prognosis Precision medicine Paclitaxel

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