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Preparation of Chemically Recyclable Poly(ether-alt-ester) by the Ring Opening Polymerization of Cyclic Monomers Synthesized by Coupling Glycolide and Epoxides

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Chinese Journal of Polymer Science 2024年第2期42卷 168-175,I0006页

作者： Feng Ren Zhuang-Zhuang Liang Ming-Xin niu Chen-Yang Hu Xuan Pang Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China

Polyester and polyether are two key oxygenated polymers, and completely alternative sequence of poly(ester-alt-ether) could efficiently combine the advantages(including flexibility, degradability, etc.) of both segments. Currently, despite their copolymers could be synthesized from one-pot mixture of cyclic esters and epoxides, perfectly alternative microstructure is very challenging to realize and typically restricted to certain monomer pairs. Moving forward, synthesizing poly(ester-alt-ether) from commercially available and largescale monomers would be a significant advance. For example, successfully commercialized poly(glycolic acid)(PGA), which is not easily soluble in polymers due to its high crystallinity and is brittle and difficult to control the degradation cycle, would encounter a new paradigm if engineered into poly(ester-altether). In this work, starting from the design of monomer with hybrid structures, we successfully synthesized a series of 1,4-dioxan-2-one containing different substituents based on glycolide(GA) and epoxides using commercially available Salen-Cr(III) and PPNCl catalytic *** new monomers underwent ring-opening polymerization(ROP) to form a series of poly(ester-alt-ether) with perfectly alternating glycolic acid and propylene glycol repeat units under catalytic system of thiourea/base. The poly(ester-alt-ether) have significantly lower glass-transition temperature than PGA. Additionally, the poly(ester-alt-ether) can be chemically recovered to monomer using Sn(Oct)2 or 1,8-diazabicyclo[5.4.0]undecane-7-ene(DBU) as a catalyst in solution, thus establishing a closed-loop life cycle. From monomers derived from GA and epoxides, this work furnishes a novel strategy for the synthesis of poly(ester-alt-ether) with chemical recyclability.

关键词： Polyester Polyether Alternative copolymer Ring-opening polymerization

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Vector field path following for a micro flapping-wing robot

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Science China(Information Sciences) 2024年第6期67卷 442-444页

作者： Haifeng HUANG Yingte LIU Tao niu Chang WANG Yao ZOU Wei HE School of Intelligence Science and Technology University of Science and Technology Beijing Institute of Artificial Intelligence University of Science and Technology Beijing Key Laboratory of Intelligent Bionic Unmanned Systems Ministry of EducationUniversity of Science and Technology Beijing

Flapping-wing robots mimic the flight patterns of natural flying creatures,granting them natural *** hold promising applications in the military reconnaissance,urban surveillance,and various other fields[1–3].However,the current limitations in size often restrict the suitability of existing bird-like flapping-wing robots,

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Polyoxometalates coupled covalent organic frameworks as highly active photothermal nanoreactor for CO_(2)cycloaddition

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Nano Research 2024年第7期17卷 5975-5984页

作者： Tian Wang Yunqing Zhu Wei Wang Junfeng niu Zhiyi Lu Peilei He School of Environmental Science and Engineering Shaanxi University of Science and TechnologyXi’an 710021China Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China University of Chinese Academy of Sciences Beijing 100049China

Covalent organic frameworks(COFs)-based nanoreactors have attracted broad interest in many fields due to their voidconfinement ***,the inherent drawback of conventional nanoreactors is the lack of internal active sites,which limits their widespread ***,we report the construction of hierarchical COF(EB-TFP)nanoreactor with pre-synthesized polyoxometalates(POM,[PV_(2)W_(10)O_(40)]^(5–)(PV_(2)W_(10)))clusters encapsulated inside of COF(POM@COF).PV_(2)W_(10)@EB-TFP anchors nucleophilic-group(Br–ions)and PV_(2)W_(10)anion cluster within the COF framework via electrostatic interactions,which not only simplifies the reaction system but also enhances catalytic *** reaction performance of the PV_(2)W_(10)@EB-TFP nanoreactor can be tuned to achieve excellent catalytic activity in CO_(2)cycloaddition reaction(CCR)for~97.63%conversion and~100%selectivity under visible light irradiation.A mechanistic study based on density functional theory(DFT)calculations and insitu characterization was also carried *** summary,we have reported a method for achieving the uniform dispersion of POM single clusters into COF nanoreactor,demonstrating the potential of POM@COF nanoreactor for synergistic photothermal catalytic CO_(2)cycloaddition.

关键词： photothermal nanoreactor CO_(2)cycloaddition polyoxometalate photothermal-synergistic catalysis covalent organic frameworks

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Fabrication of Molecularly Imprinted Electrospun Nanofibers with Mono-amidoxime Functional Ligand for Efficient Decontamination of Toxic Organophosphates

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Chinese Journal of Polymer Science 2024年第4期42卷 446-456页

作者： Lan Wang Peng Jiang Ya-Lin niu Jun-Peng Cao Tian-Ying Guo Key Laboratory of Functional Polymer Materials Ministry of EducationInstitute of Polymer ChemistryCollege of Chemistry and Frontier Science Center for the Creation of New Organic SubstancesNankai UniversityTianjin300071China

There is an urgent imperative to discover practical and efficacious artificial catalysts for the expeditious decontamination of toxic organophosphates. Herein, we propose a novel molecularly imprinted approach utilizing electrospun fiber scaffolds. Specifically, an amidoxime-based functional polymer (PMAOX) has been synthesized, which contains amidoxime groups that can act as nucleophiles and ligands for the formation of catalytic active sites. This polymer was blended with polyacrylonitrile (PAN), a well-processable material, to prepare a nanofiber mat using electrospinning techniques. Then, the amidoxime side groups on fiber surface were further cross-linked after the molecular coordination of templates to complete the molecularly imprinting process. This approach can not only enhance the content of functional molecularly imprinted polymers without affecting structural stability, but also combines surface MI technology to fully expose and leverage the advantages of active sites. The as prepared molecularly imprinted electrospun nanofibers MIF-Zn-PMAOX/PAN-6/4 catalyzes the degradation of paraoxon with a half-life of 32 min, and MIF-Ag-PMAOX/PAN catalyzes the degradation of parathion with a half-life of 18 min. The maximum catalytic rate evidence rate enhancements nearly 3700-fold of the self-hydrolysis. Thus, the mono-amidoxime based molecularly imprinted fibers demonstrate the versatility and superiority as self-detoxifying for organophosphates.

关键词： Organophosphateshydrolysis Electrospinning Molecular imprinting

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Research progress toward the influence of mosquito salivary proteins on the transmission of mosquito-borne viruses

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Insect Science 2024年第3期31卷 663-673页

作者： Zhao-Yang Wang Kai-Xiao Nie Ji-Chen niu Gong Cheng Tsinghua University-Peking University Joint Center for Life Sciences School of MedicineTsinghua UniversityBejingChina Institute of Infectious Diseases Shenzhen Bay LaboratoryShenzhenGuangdongChina Department of Pathogen Biology School of Basic MedicineShandong First Medical University&Shandong Academy of Medical SciencesJinanChina

Mosquito-borne viruses(MBVs)are a large class of viruses transmitted mainly through mosquito bites,including dengue virus,Zika virus,Japanese encephalitis virus,West Nile virus,and chikungunya virus,which pose a major threat to the health of people around the *** global warming and extended human activities,the incidence of many MBVs has increased *** saliva contains a variety of bioactive protein *** not only enable blood feeding but also play a crucial role in regulating local infection at the bite site and the remote dissemination of MBVs as well as in remodeling the innate and adaptive immune responses of host ***,we review the physiological functions of mosquito salivary proteins(MSPs)in detail,the influence and the underlying mechanism of MSPs on the transmission of MBVs,and the current progress and issues that urgently need to be addressed in the research and development of MSP-based MBV transmission blocking vaccines.

关键词： immune response mosquito-borne virus mosquito salivary protein saliva vaccine transmission

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Time-dependent deviation of bridge pile foundations caused by adjacent large-area surcharge loads in soft soils and its preventive measures

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 184-201页

作者： Shuanglong LI Limin WEI Jingtai niu Zhiping DENG Bangbin WU Wuwen QIAN Feifei HE School of Hydraulic Engineering Nanchang Institute of TechnologyNanchang 330099China School of Civil Engineering Central South UniversityChangsha 410075China

Time-dependent characteristics(TDCs)have been neglected in most previous studies investigating the deviation mechanisms of bridge pile foundations and evaluating the effectiveness of preventive *** this study,the stress-strain-time characteristics of soft soils were illustrated by consolidation-creep tests based on a typical engineering *** extended Koppejan model was developed and then embedded in a finite element(FE)model via a user-material subroutine(UMAT).Based on the validated FE model,the time-dependent deformation mechanism of the pile foundation was revealed,and the preventive effect of applying micropiles and stress-release holes to control the deviation was *** results show that the calculated maximum lateral displacement of the cap differs from the measured one by 6.5%,indicating that the derived extended Koppejan model reproduced the deviation process of the bridge cap-pile foundation with *** additional load acting on the pile side caused by soil lateral deformation was mainly concentrated within the soft soil layer and increased with the increase in load *** with t=3 d(where t is surcharge time),the maximum lateral additional pressure acting on Pile 2#increased by approximately 47.0%at t=224 *** bridge pile foundation deviation in deep soft soils,stress-release holes can provide better prevention compared to micropiles and are therefore recommended.

关键词： bridge pile foundation surcharge load soft soil time-dependent deformation interaction mechanism preventive measure

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Design,Simulation and Kinematic Validation of a Hip Prosthetic Mechanism with a Multimotor Function

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Journal of Bionic Engineering 2024年第3期21卷 1321-1333页

作者： Majun Song Zhongyi Li Jingjing Jiang Weihai Chen Sheng Guo Hao Zheng Lianzheng niu Hangzhou Innovation Institute Beihang UniversityHangzhou310051China Hangzhou Huacheng Software Technology Co.Ltd. Hangzhou310051China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China

We previously developed a powered hip prosthetic mechanism with kinematic functions of hip flexion-extension and abduction-adduction,and its theoretical and simulation-based kinematics were *** internal-external hip rotation has a positive effect on the movements of human lower limbs according to medical research,we developed a novel hip prosthetic mechanism based on a previous hip prosthesis that possesses motion characteristics similar to those of a human bionic hip,and the motion characteristics of multiple Degrees-of-Freedom(DoFs)were analyzed after kinematic ***,a walking model of the human‒machine model was established,and the walking stability of an amputee,which reflects the rehabilitation effect,was explored while the hip prosthetic mechanism considered the internal-external rotation of the ***,a prototype and its verification platform were built,and kinematic validation of the hip prosthetic mechanism was carried *** results showed that the designed Parallel Mechanism(PM)possesses human-like motion characteristics similar to those of a human bionic hip and can be used as a hip ***,the existing motion characteristic of internal-external hip rotation can enhance the walking stability of an amputee via this hip prosthetic mechanism.

关键词： Hip prosthetic mechanism Parallel mechanism Walking stability Kinematic validation

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Microstructural Evolutions and Mechanical Properties of Energetic Al_(1) (TiZrNbTaMoCr)_(15) High-Entropy Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 620-632页

作者： Xuan-Hong Cai Zhen-Hua Wang Ben niu Jin-Feng Li Qing Wang Show authors Key Laboratory of Materials Modification By Laser Ion and Electron Beams(Ministry of Education)Engineering Research Center of High Entropy Alloy Materials(Liaoning Province)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Institute of Materials China Academy of Engineering PhysicsMianyang621908China

The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.

关键词： Refractory high-entropy alloy Coherent microstructure Mechanical property Exothermic enthalpy

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High adsorption selectivity of activated carbon and carbon molecular sieve boosting CO_(2)/N_(2) and CH_(4)/N_(2) separation

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Chinese Journal of Chemical Engineering 2024年第3期67卷 282-297页

作者： Siang Chen Wenling Wu Zhaoyang niu Deqi Kong Wenbin Li Zhongli Tang Donghui Zhang The Research Center of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Flue gas and coal bed methane are two important sources of greenhouse *** swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is *** this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 *** experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric *** the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular ***,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) *** study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

关键词： Activated carbon Carbon molecular sieve Adsorbent evaluation Adsorption equilibrium and kinetics Heat of adsorption Selectivity

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Metal-Organic Framework Enabling Poly(Vinylidene Fluoride)-Based Polymer Electrolyte for Dendrite-Free and Long-Lifespan Sodium Metal Batteries

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Energy & Environmental Materials 2024年第1期7卷 68-76页

作者： Yusi Lei Liang Yue Yuruo Qi Yubin niu Shujuan Bao Jie Song Maowen Xu Faculty of Materials and Energy Institute for Clean Energy&Advanced MaterialsSouthwest UniversityChongqing 400715China Shandong Zero-One-Four Advanced Materials Co. Ltd.Feicheng 271099China

Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and,more importantly,cause internal short circuit and lead to thermal runaway and ***,sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries(SMBs).Herein,a design concept for the incorporation of metal-organic framework(MOF)in polymer matrix(polyvinylidene fluoride-hexafluoropropylene)is practiced to prepare a novel gel polymer electrolyte(PH@MOF polymer-based electrolyte[GPE])and thus to achieve high-performance *** addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na^(+)but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction.A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm^(-2)with areal capacity of 5 mA h cm^(-2)is achieved by symmetric cells based on the resulted GPE while the Na_(3)V_(2)O_(2)(PO_(4))_(2)F@rGO(NVOPF)|PH@MOF|Nacell also displays impressive specific cycling capacity(113.3 mA h g^(-1)at 1 C)and rate capability with considerable capacity retention.

关键词： dendrite-free gel polymer electrolyte metal organic framework sodium batteries

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