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Polymer-to-Monomers Chemically recyclable Poly(imide-imine)Plastics with Extreme-Condition resistance and Flame retardancy

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Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： Zhen-Yu Wang xiao-Kong liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-Cr-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-Cr-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-Cr-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile str.ngth as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-Cr-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-Cr-PII plastic with excellent flame *** PtM-Cr-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-Cr-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-Cr-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

Thermodynamic nature of black holes in coexistence region

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei Yu-xiao liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Energy-efficient buffer and service rate allocation in manufactur.ng systems using hybrid machine learning and evolutionary algorithms

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Advances in Manufactur.ng 2024年第2期12卷 227-251页

作者： Si-xiao Gao Hui liu Jun Ota Key Laboratory of Traffic Safety on Track of Ministry of Education Institute of Artificial Intelligence and Robotics(IAIR)School of Traffic and Transportation EngineeringCentral South UniversityChangsha410075People’s Republic of China research into Artifacts Center for Engineer.ng School of EngineeringThe University of TokyoTokyoJapan

Currently,simultaneous buffer and service rate allocation is a topic of interest in the optimization of manufactur.ng *** allocation problems have been solved previously to satisfy economic requirements;however,owing to the progress of green manufactur.ng,energy conservation and environmental protection have become increasingly ***,an energy-efficient approach is developed to maximize the throughput and minimize the energy consumption of manufactur.ng systems,subject to the total buffer capacity,total service rate,and predefined energy *** energy-efficient approach integrates the simulated annealing-non-dominated sorting genetic algorithm-II with the honey badger algorithm-histogram-based gradient boosting regression *** former algorithm searches for Pareto-optimal solutions of sufficient *** latter algorithm builds prediction models to rapidly calculate the throughput,energy consumption,and energy *** examples show that the proposed hybrid approach can achieve a better solution quality compared with previously reported ***,the prediction models can rapidly evaluate manufactur.ng systems with sufficient *** study benefits the multi-objective optimization of green manufactur.ng systems.

关键词： Energy-efficient allocation Multi-objective optimization Energy efficiency Energy consumption Machine learning

Active MoS_(2)-based electrode for green ammonia synthesis

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Chinese Journal of Chemical Engineer.ng 2024年第1期65卷 268-275页

作者： Xin liu Lei Yang Tao Wei Shanping liu Beibei xiao School of Energy and Power Engineer.ng Jiangsu University of Science and TechnologyZhenjiang 212003China Institute Charles Gerhardt Montpellier UMR-5253Universite de MontpellierCNRSENSCMPlace E.Bataillon34095 Montpellier Cedex 05France

Nitrogen electro-reduction under mild conditions is one promising alternative approach of the energyconsuming Haber-Bosch process for the artificial ammonia *** critical aspect to unlocking this technology is to discover the catalysts with high selectivity and *** this work,the N_(2)-to-NH_(3)conversion on the functional MoS_(2)is fully investigated by density functional theory calculations since the layered MoS_(2)provides the ideal platform for the elaborating copies of the nitrogenase found in nature,wherein the functionalization is achieved via basal-adsorption,basal-substitution or edge-substitution of transition metal *** results reveal that the edge-functionalization is a feasible strategy for the activity promotion;however,the basal-adsorption and basal-substitution separately suffer from the electrochemical instability and the Nrr ***,MoS_(2)functionalized via edge W-substitution exhibits an exceptional *** energetically favored reaction pathway is through the distal pathway and a limiting potential is less than 0.20 ***,this work escalates the rational design of the high-effective catalysts for nitrogen fixation and provides the explanation why the predicated catalyst have a good performance,paving the guidance for the experiments.

关键词： Nitrogen reduction reaction Density functional theory calculations Molybdenum disulfide Electrochemistry Catalyst Thermodynamics

High-sensitivity formaldehyde gas sensor based on Ce-doped urchin-like SnO_(2) nanowires derived from calcination of Sn-MOFs

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Frontiers of Materials Science 2024年第1期18卷 29-43页

作者： Wei xiao Wei Yang Shantang liu Hubei Key Lab of Novel reactor&Green Chemical Technology School of Chemistry and Environmental EngineeringWuhan Institute of TechnologyWuhan 430073China Hubei Key Laboratory of Wudang Local Chinese Medicine research Department of ChemistrySchool of Pharmaceutical SciencesHubei University of MedicineShiyan 442000China

Metal-organic frameworks(MOFs)have attracted widespread attention due to their regular structures,multiple material centers,and various *** are always considered as one kind of ideal templates for developing highly sensitive and selective gas *** this study,the advantages of MOFs with the high specific surface area(71.9891 m^(2)·g^(-1))and uniform morphology were fully utilized,and urchin-like SnO_(2) nanowires were obtained by the hydrothermal method followed by the calcination using Sn-MOFs consisting of the ligand of C_(9)H_(6)O_(6)(H_(3)BTC)and Sn/Ce center ions as sacrificial *** unique urchin-like nanowire structure facilitated gas diffusion and adsorption,resulting in superior gas sensitivity.A series of Ce-doped SnO_(2) nanowires with different doping ratios were synthesized,and their gas sensing properties towards formaldehyde were *** resulted Ce-SnO_(2) was revealed to have high sensitivity(201.2 at 250℃),rapid response(4 s),long-term stability,and good repeatability for formaldehyde sensing,and the gas sensing mechanism of Ce-SnO_(2) exposed to formaldehyde was also systematically discussed.

关键词： Ce-SnO_(2) SnO_(2) gas sensor formaldehyde Sn-MOF

An efficient parallel algorithm of variational nodal method for heterogeneous neutron transport problems

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Nuclear Science and Techniques 2024年第4期35卷 29-45页

作者： Han Yin xiao-Jing liu Teng-Fei Zhang School of Nuclear Science and Engineer.ng Shanghai Jiao Tong UniversityShanghai 2002040China

The heterogeneous variational nodal method(HVNM)has emerged as a potential approach for solving high-fidelity neutron transport ***,achieving accurate results with HVNM in large-scale problems using high-fidelity models has been challenging due to the prohibitive computational *** paper presents an efficient parallel algorithm tailored for HVNM based on the Message Passing Interface *** algorithm evenly distributes the response matrix sets among processors dur.ng the matrix formation process,thus enabling independent construction without *** the formation tasks are completed,a collective operation merges and shares the matrix sets among the *** the solution process,the problem domain is decomposed into subdomains assigned to specific processors,and the red-black Gauss-Seidel iteration is employed within each subdomain to solve the response matrix ***-to-point communication is conducted between adjacent subdomains to exchange data along the *** accuracy and efficiency of the parallel algorithm are verified using the KAIST and Jrr-3 test *** results obtained with multiple processors agree well with those obtained from Monte Carlo *** parallelization of HVNM results in eigenvalue errors of 31 pcm/-90 pcm and fission rate rMS errors of 1.22%/0.66%,respectively,for the 3D KAIST problem and the 3D Jrr-3 *** addition,the parallel algorithm significantly reduces computation time,with an efficiency of 68.51% using 36 processors in the KAIST problem and 77.14% using 144 processors in the Jrr-3 problem.

关键词： Neutron transport Variational nodal method Parallelization KAIST Jrr-3

Collision-free parking recommendation based on multi-agent reinforcement learning in vehicular crowdsensing

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Digital Communications and Networks 2024年第3期10卷 609-619页

作者： Xin Li Xinghua Lei Xiuwen liu Hang xiao College of Computer Science and Technology China University of Petroleum(East China)QingDao266580China

The recent proliferation of Fifth-Generation(5G)networks and Sixth-Generation(6G)networks has given rise to Vehicular Crowd Sensing(VCS)systems which solve parking collisions by effectively incentivizing vehicle ***,instead of being an isolated module,the incentive mechanism usually interacts with other *** on this,we capture this synergy and propose a Collision-free Parking recommendation(CPr),a novel VCS system framework that integrates an incentive mechanism,a non-cooperative VCS game,and a multi-agent reinforcement learning algorithm,to derive an optimal parking strategy in real ***,we utilize an LSTM method to predict parking areas roughly for recommendations *** incentive mechanism is designed to motivate vehicle participation by consider.ng dynamically priced parking tasks and social network *** order to cope with stochastic parking collisions,its non-cooperative VCS game further analyzes the uncertain interactions between vehicles in parking *** its multi-agent reinforcement learning algorithm models the VCS campaign as a multi-agent Markov decision process that not only derives the optimal collision-free parking strategy for each vehicle independently,but also proves that the optimal parking strategy for each vehicle is ***,numerical results demonstrate that CPr can accomplish parking tasks at a 99.7%accuracy compared with other baselines,efficiently recommending parking spaces.

关键词： Incentive mechanism Non-cooperative VCS game Multi-agent reinforcement learning Collision-free parking strategy Vehicular crowdsensing

Solvent transport dynamics and its effect on evolution of mechanical properties of nitrocellulose(NC)-based propellants under hot-air drying process

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Defence Technology（防务技术） 2024年第2期32卷 262-270页

作者： Enfa Fu Mingjun Yi Qianling liu Zhenggang xiao Key Laboratory of Special Energy Materials Ministry of EducationSchool of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing 210094People's Republic of China

Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant ***,few research on solvent transport dynamics within NC-based propellants was reported,and its effect on the evolution of mechanical properties was not interpreted *** study is conducted to gain a comprehensive understanding of hot-air drying for NC-based propellants and clarify the effect of temperature on solvent transport behavior and further the change of mechanical properties dur.ng *** drying kinetic curves show the drying time required is decreased but the steady solvent content is increased and the drying rate is obviously increased with the increase of hot-air temperatures,indicating hot-air temperatures have a significant effect on drying kinetics.A modified drying model was established,and results show it is more appropriate to describe solvent transport behavior within NC-based ***,two linear equations were established to exhibit the relationship between solvent content and its effect on the change of tensile properties,and the decrease of residual solvent content causes an obvious increase of tensile str.ngth and tensile modulus of propellant products,indicating its mechanical properties can be partly improved by adjustment of residual solvent *** outcomes can be used to clarify solvent transport mechanisms and optimize drying process parameters of double-based gun propellants.

关键词： Nitrocellulose-based propellants Solvent transport dynamics Mechanical properties Drying kinetics Effective solvent diffusion coefficient

Non-contact and full-field online monitor.ng of cur.ng temperature dur.ng the in-situ heating process based on deep learning

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Advances in Manufactur.ng 2024年第1期12卷 167-176页

作者： Qiang-Qiang liu Shu-Ting liu Ying-Guang Li Xu liu xiao-Zhong Hao College of Mechanical and Electrical Engineer.ng Nanjing University of Aeronautics and AstronauticsNanjing210016People’s Republic of China School of Mechanical and Power Engineer.ng Nanjing Tech UniversityNanjing211816People’s Republic of China

Online monitor.ng of the cur.ng temperature field is essential to improving the quality and efficiency of the manufactur.ng process of composite *** embedded sensor-based technologies have difficulty monitor.ng the full temperature field or have to introduce heterogeneous items that could have an undesired impact on the *** this paper,a non-contact,full-field monitor.ng method based on deep learning that predicts the internal temperature field of composite parts in real time using surface temperature measurements of auxiliary materials is *** the proposed method,an average temperature monitor.ng accuracy of 97%is achieved in various heating *** addition,this method also demonstrates satisfying feasibility when a str.nger thermal barrier covers the *** method was experimentally validated dur.ng the self-resistance electric heating process,in which the monitor.ng accuracy reached 93.1%.This method can potentially be applied to automated manufactur.ng and process control in the composites industry.

关键词： Online monitor.ng Cur.ng temperature field Deep learning(DL) In-situ heating