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Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

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Journal of Advanced Ceramics 2024年第7期13卷 976-986页

作者： lin Dong Wen-qi Yang lin Chen guan-Jun Yang Chang-Jiu Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Xi’an Aerospace Engine Company Limited in China Aerospace Science and Technology Corporation Xi’an 710065China

The lifetime of Si-based environmental barrier coatings(EBCs)is constrained by thermally grown SiO_(2)oxidelayer(SiO_(2)-TgO),which can cause premature cracking and *** address this issue,a new approach for surfacemodification using aluminum is *** oxidation performance was examined in a 50 vol%H_(2)O-50 vol%O_(2)environment at 1350℃for up to 300 *** results indicate that a dense ytterbium aluminum garnet(YbAg)layer wasformed after modification,decreasing the porosity by 80%.Due to the elimination of fast diffusion channels and the lowoxygen permeability of YbAg,aluminum modification significantly reduced the growth rate of SiO_(2)-TgO by nearly twoorders of ***,its thickness decreased by more than 70%after 300 h of exposure.A diffusioncontrolled oxidation mechanism indicates that the modified dense surface is equivalent to an initial SiO_(2)layer with a specificthickness,causing a shift in the oxidation time and increasing the oxidation *** research provides valuableinsights for designing Si-based EBC with improved lifetimes.

关键词： environmental barrier coating(EBC) oxidation modification diffusion cracking

Low-temperature chemistry in plasma-driven ammonia oxidative pyrolysis

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green Energy & Environment 2024年第9期9卷 1477-1488页

作者： Mingming Zhang qi Chen guangzhao Zhou Jintao Sun He lin School of Mechanical Electronic and Control Engineering Beijing Jiaotong University School of Mechanical Engineering Shanghai Jiao Tong University

Ammonia is gaining increasing attention as a green alternative fuel for achieving large-scale carbon emission reduction. Despite its potential technical prospects, the harsh ignition conditions and slow flame propagation speed of ammonia pose significant challenges to its application in engines. Non-equilibrium plasma has been identified as a promising method, but current research on plasma-enhanced ammonia combustion is limited and primarily focuses on ignition characteristics revealed by kinetic models. In this study, low-temperature and low-pressure chemistry in plasma-assisted ammonia oxidative pyrolysis is investigated by integrated studies of steady-state gC measurements and mathematical simulation. The detailed kinetic mechanism of NH3decomposition in plasma-driven Ar/NH3and Ar/NH3/O2mixtures has been developed. The numerical model has good agreements with the experimental measurements in NH3/O2consumption and N2/H2generation, which demonstrates the rationality of modelling. Based on the modelling results, species density profiles, path flux and sensitivity analysis for the key plasmaproduced species such as NH2, NH, H2, OH, H, O, O（1D）, O2（a1△g）, O2（b1∑g+）, Ar*, H-, Ar+, NH3+, O2-in the discharge and afterglow are analyzed in detail to illustrate the effectiveness of the active species on NH3excitation and decomposition at low temperature and relatively higher E/N values. The results revealed that NH2, NH, H as well as H2are primarily generated through the electron collision reactions e + NH3→ e + NH2+ H, e + NH3→ e + NH + H2and the excited-argon collision reaction Ar*+ NH3+ H → Ar + NH2+ 2H, which will then react with highly reactive oxidative species such as O2*, O*, O, OH, and O2to produce stable products of NOx and H2O. NH3→ NH is found a specific pathway for NH3consumption with plasma assistance, which further highlights the enhanced kinetic effects.

关键词： Non-equilibrium plasma Ammonia fuel Oxidative pyrolysis Pathway flux analysis Sensitivity analysis

Hybrid pedestrian positioning system using wearable inertial sensors and ultrasonic ranging

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Defence Technology（防务技术） 2024年第3期33卷 327-338页

作者： lin qi Yu Liu Chuanshun gao Tao Feng Yue Yu School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Department of Land Surveying and geo-Informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,*** performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration *** paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint *** addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial ***,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall *** results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.

关键词： Pedestrian positioning system Wearable inertial sensors Ultrasonic ranging Deep-learning Data and model dual-driven

Fundamentals and progress of the manifold method based on independent covers

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Science China(Technological Sciences) 2024年第4期67卷 966-991页

作者： SU HaiDong lin ShaoZhong XIE Zhiqiang gONg Yaqi qi YongFeng Material and Engineering Structure Department Yangtze River Scientific Research InstituteWuhan 430010China Research Center of water Engineering Safety and Disaster Prevention of Ministry of water Resources Wuhan 430010China

Aiming to solve mesh generation,computational stability,accuracy control,and other problems encountered with existing numerical methods,such as the finite element method and the finite volume method,a new numerical computational method for continuum mechanics,namely the manifold method based on independent covers(MMIC),is proposed based on the concept of mathematical manifolds,to form partitioned series solutions of partial differential *** partitions,the cover meshes have the characteristics of arbitrary shape,arbitrary connection,and arbitrary *** are expected to fundamentally solve the mesh generation problem and can also simulate the precise geometric boundaries of the CAD model and strictly impose boundary *** the selection of series solutions,local analytical solutions(such as series solutions at crack tips and series solutions in infinite domains)or proper forms of complete series can be used to reflect the local or global characteristics of the physical field to accelerate *** applications are presented.A new method of beam,plate,and shell analysis is *** deformation characteristics of beams,plates,and shells are simulated with polynomial series of suitable forms,and the analysis of curved beams and shells with accurate geometric representation is *** the static elastic analysis of two-dimensional structures,a mesh splitting algorithm is proposed,and h-p version adaptive analysis is carried out with error ***,automatic computation integrated with CAD is *** analysis is also attempted for the solution of differential equations of *** the one-dimensional convection-diffusion equation and Burgers equation,calculation results with high precision are obtained in strong convection and shock wave simulations,avoiding nonphysical *** solving the two-dimensional incompressible Navier-Stokes equation is also *** series solution formula is used to o

关键词： series solutions mesh generation adaptive analysis fixed meshes numerical manifold method

Triclosan-conjugated,Lipase-responsive Polymeric Micelles for Eradication of Staphylococcal Biofilms

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Chinese Journal of Polymer Science 2024年第6期42卷 718-728页

作者： Yan-qiang Huang Yuan-Feng Li Yong Liu lin-qi Shi guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance Youjiang Medical University for NationalitiesBaise533000China Translational Medicine Laboratory the First Affiliated Hospital of Wenzhou Medical UniversityWenzhou325035China Wenzhou Institute University of Chinese Academy of SciencesWenzhou325001China State Key Laboratory of Medicinal Chemical Biology Key Laboratory of Functional Polymer Materials of Ministry of Educationand Institute of Polymer ChemistryCollege of ChemistryNankai UniversityTianjin300071China

Bacterial biofilms present a significant challenge in treating drug-resistant infections,necessitating the development of innovative *** this study,we introduce triclosan-conjugated,lipase-responsive polymeric micelles designed to exploit biofilm properties and serve as a responsive drug delivery *** micelles were created using an amphiphilic block polymer synthesized via ring-opening polymerization ofε-caprolactone(CL)and triclosan-containing cyclic trimethylene carbonate(MTC-Tri).Poly(ethylene glycol)(PEg-OH)acted as the macro-initiator,resulting in micelles with a PEg shell that facilitated their penetration into bacterial *** important advantage of our micelles lies in their interaction with local bacterial lipases within *** lipases triggered rapid micelle degradation,releasing triclosan in a controlled *** liberated triclosan effectively eliminated bacteria embedded in the ***,the triclosan-conjugated micelles displayed minimal toxicity to murine fibroblasts,indicating their biocompatibility and *** finding emphasizes the potential application of these micelles in combatting drug resistance observed in bacterial *** triclosan-conjugated,lipase-responsive polymeric micelles exhibit promising characteristics for addressing drug resistance in bacterial *** harnessing biofilm properties and implementing a responsive drug delivery system,we seek to provide an effective solution in the fight against drug-resistant bacteria.

关键词： Self-assembly Polymer prodrug Ring-opening polymerization Biofilm eradication Cytotoxicity

The principle and amelioration of lithium plating in fast-charging lithium-ion batteries

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Journal of Energy Chemistry 2024年第10期97卷 453-459,I0009页

作者： Yi Yang Xia-lin Zhong Lei Xu Zhuo-lin Yang Chong Yan Jia-qi Huang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Yangtze River Delta graduate School of Beijing Institute of Technology Jiaxing 314003ZhejiangChina

Fast charging is restricted primarily by the risk of lithium(Li)plating,a side reaction that can lead to the rapid capacity decay and dendrite-induced thermal runaway of lithium-ion batteries(LIBs).Investigation on the intrinsic mechanism and the position of Li plating is crucial to improving the fast rechargeability and safety of ***,we investigate the Li plating behavior in porous electrodes under the restricted transport of Li^(+).Based on the theoretical model,it can be concluded that the Li plating on the anodeseparator interface(ASI)is thermodynamically feasible and kinetically ***,the prior deposition of metal Li on the ASI rather than the anode-current collector interface(ACI)is verified *** order to facilitate the transfer of Li^(+)among the electrode and improve the utilization of active materials without Li plating,a bilayer asymmetric anode composed of graphite and hard carbon(gH)is *** and simulation results suggest that the gH hybrid electrode homogenizes the lithiated-rate throughout the electrode and outperforms the pure graphite electrode in terms of the rate performance and inhibition of Li *** work provides new insights into the behavior of Li plating and the rational design of electrode structure.

关键词： graphite Hard carbon Fast charging Lithium plating Lithium-ion batteries

Sustained release of vascular endothelial growth factor A and basic fibroblast growth factor from nanofiber membranes reduces oxygen/glucose deprivation-induced injury to neurovascular units

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Neural Regeneration Research 2024年第4期19卷 887-894页

作者： Yifang Wu Jun Sun qi lin Dapeng wa.g Jian Hai Department of Neurosurgery Tongji HospitalSchool of MedicineTongji University Department of Pharmacy Institute of Medical SciencesShanghai Jiao Tong University School of Medicine

Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor(VEgFA/b FgF)expression in the penumbra of cerebral ischemia can increase vascular volume,reduce lesion volume,and enhance neural cell proliferation and differentiation,thereby exerting neuroprotective ***,the beneficial effects of endogenous VEgFA/b FgF are limited as their expression is only transiently *** this study,we generated multilayered nanofiber membranes loaded with VEgFA/b FgF using layer-by-layer self-assembly and electrospinning *** found that a membrane containing 10 layers had an ideal ultrastructure and could efficiently and stably release growth factors for more than 1 *** 10-layered nanofiber membrane promoted brain microvascular endothelial cell tube formation and proliferation,inhibited neuronal apoptosis,upregulated the expression of tight junction proteins,and improved the viability of various cellular components of neurovascular units under conditions of oxygen/glucose ***,this nanofiber membrane decreased the expression of Janus kinase-2/signal transducer and activator of transcription-3(JAK2/STAT3),Bax/Bcl-2,and cleaved ***,this nanofiber membrane exhibits a neuroprotective effect on oxygen/glucose-deprived neurovascular units by inhibiting the JAK2/STAT3 pathway.

关键词： brain ischemia brain microvascular endothelial cell nanofiber membrane neurovascular unit

Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for giga/Terahertz Electromagnetic Shielding and Photothermal Conversion

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Nano-Micro Letters 2024年第9期16卷 161-179页

作者： Tian Mai Lei Chen Pei‑lin wa.g qi Liu Ming‑guo Ma Research Center of Biomass Clean Utilization MOE Engineering Research Center of Forestry Biomass Materials and BioenergyBeijing Key Laboratory of Lignocellulosic ChemistryCollege of Materials Science and TechnologyBeijing Forestry UniversityBeijing 100083People’s Republic of China State Silica-Based Materials Laboratory of Anhui Province Bengbu 233000People’s Republic of China

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become *** the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge ***,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration *** HMN composite films exhibit excellent EMI shielding effectiveness performance in the gHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 ***,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),*** unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance *** features make the HMN composite film a promising candidate for advanced EMI devices for future 6g communication and the protection of electronic equipment in cold environments.

关键词： Metal-organic frameworks MXene Nanocellulose Electromagnetic shielding Photothermal conversion

Rheological Behaviors of Polymers with Nanoparticles Tethered at Each End

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Chinese Journal of Polymer Science 2024年第3期42卷 400-406,I0009页

作者： Song-qi Zhang Wen-qing wa.g Jia-Ping lin Li-Quan wa.g Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from-1/2 to-3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology.

关键词： Polymer rheology Modulus Viscosity Molecular dynamics