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Liquid metal in prohibiting polysulfides shuttling in metal sulfides anode for sodium-ion batteries

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Journal of Energy Chemistry 2024年第9期96卷 559-567页

作者： Xiaobo zheng Xinwei Guan Xuan Cheng Xiaoning Li Yang Fu Yitong Li zhi zheng Weikong Pang Xun Xu peng Li Tianyi Ma Institute for Superconducting&Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongWollongongNSW 2522Australia School of Science RMIT UniversityMelbourneVIC 3000Australia CSIRO Manufacturing ClaytonVIC 3168Australia

Metal sulfides are a class of promising anode materials for sodium-ion batteries(SIBs)owing to their high theoretical specific ***,the reactant products(polysulfides)could dissolve into electrolyte,shuttle across separator,and react with sodium anode,leading to severe capacity loss and safety ***,for the first time,gallium(Ga)-based liquid metal(LM)alloy is incorporated with MoS_(2)nanosheets to work as an anode in *** electron-rich,ultrahigh electrical conductivity,and self-healing properties of LM endow the heterostructured MoS_(2)-LM with highly improved conductivity and electrode ***,LM is demonstrated to have excellent capability for the adsorption of polysulfides(e.g.,Na_(2)S,Na_(2)S_(6),and S_(8))and subsequent catalytic conversion of Na_(2)***,the MoS_(2)-LM electrode exhibits superior ion diffusion kinetics and long cycling performance in SIBs and even in lithium/potassium-ion battery(LIB/PIB)systems,far better than those electrodes with conventional binders(polyvinylidene difluoride(PVDF)and sodium carboxymethyl cellulose(CMC)).This work provides a unique material design concept based on Ga-based liquid metal alloy for metal sulfide anodes in rechargeable battery systems and beyond.

关键词： GalnSn liquid metal alloy MoS_(2) Polysulfides shuttle effects Catalytic conversion Sodium-ion batteries

NUMERICAL SIMULATION OF PROPAGATION AND BREAKING PROCESSES OF A FOCUSED WAVES GROUP

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Journal of Hydrodynamics 2012年第3期24卷 399-409页

作者： HUANG Zong-liu LIN peng-zhi State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

A two-dimensional numerical wave flume is developed to study the focused waves group propagation and the consequent breaking processes. The numerical model is based on the Reynolds-Averaged Navier-Stokes （PANS） equations, with the standard k - c turbulence model to simulate the turbulence effects. To track the complicated and broken free-surface, the Volume Of Fluid （VOF） method is employed. The numerical model combines the ＂Partial Cell Treatment （PCT）＂ method with the ＂Locally Relative Stationary （LRS）＂ concept to treat the moving wave paddle so that various waves can be generated directly in a fixed Cartesian grid system. The theoretical results of the linear and nonlinear waves are used to validate the numerical wave flume firstly, and then a plunging breaking wave created by a focused waves group is simulated. The numerical results are compared to the experimental data and other simulation results, with very good agreements. The turbulence intensity, the flow field and the energy dissipation in the breaking processes are analyzed based on the numerical results. It is shown that the present numerical model is efficient and accurate for studying the waves group generation, the waves packet propagation, and the wave breaking processes.

关键词： focused waves group plunging breaking Volume Of Fluid (VOF) k - ε turbulence model irregular wave maker

Numerical Simulation of the Vortex-Induced Vibration of A Curved Flexible Riser in Shear Flow

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China Ocean Engineering 2018年第3期32卷 301-311页

作者： ZHU Hong-jun LIN peng-zhi State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

A series of fully three-dimensional(3 D) numerical simulations of flow past a free-to-oscillate curved flexible riser in shear flow were conducted at Reynolds number of 185–1015. The numerical results obtained by the two-way fluid–structure interaction(FSI) simulations are in good agreement with the experimental results reported in the earlier study. It is further found that the frequency transition is out of phase not only in the inline(IL) and crossflow(CF) directions but also along the span direction. The mode competition leads to the non-zero nodes of the rootmean-square(RMS) amplitude and the relatively chaotic trajectories. The fluid–structure interaction is to some extent reflected by the transverse velocity of the ambient fluid, which reaches the maximum value when the riser reaches the equilibrium position. Moreover, the local maximum transverse velocities occur at the peak CF amplitudes, and the values are relatively large when the vibration is in the resonance regions. The 3 D vortex columns are shed nearly parallel to the axis of the curved flexible riser. As the local Reynolds number increases from 0 at the bottom of the riser to the maximum value at the top, the wake undergoes a transition from a two-dimensional structure to a 3 D one. More irregular small-scale vortices appeared at the wake region of the riser, undergoing large amplitude responses.

关键词： vortex-induced vibration flexible riser shear flow fluid–structure interaction computational fluid dynamics

Precipitation of spherical boehmite from concentrated sodium aluminate solution by adding gibbsite as seed

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 954-963页

作者： Gui-hua Liu zheng Li Xiao-bin Li Tian-gui Qi zhi-hong peng Qiu-sheng Zhou School of Metallurgy and Environment Central South University

The precipitation of spherical boehmite was studied by surface energy calculations, measurements of precipitation ratios, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The surface energy calculation results show that the(001) and(112) planes of gibbsite surfaces are remarkably stable because of their low surface energies. In addition, the(010) plane of boehmite grows preferentially during precipitation because of its low surface energy. Thus, we propose a method to precipitate spherical boehmite from a supersaturated sodium aluminate solution by adding gibbsite as seed in a heterogeneous system. In this method, gibbsite acts as the preliminary seed and saturation modifier. The results show that the fine boehmite first nucleates on the(001) and(112) planes of gibbsite and then grows vertically on the(001) and(112) basal planes of gibbsite via self-assembly, thereby forming spherical boehmite. Simultaneously, gibbsite is dissolved into the aluminate solution to maintain the saturation for the precipitation of boehmite. The precipitation ratio fluctuates(forming an M-shaped curve) because of gibbsite dissolution and boehmite precipitation. The mechanism of boehmite precipitation was further discussed on the basis of the differences in surface energy and solubility between gibbsite and boehmite. This study provides an environmentally friendly and economical method to prepare specific boehmite in a heterogeneous system.

关键词： precipitation sodium aluminate solution morphology boehmite gibbsite surface energy

A novel application of the SAWD-Sabatier-SPE integrated system for CO_2 removal and O_2 regeneration in submarine cabins during prolonged voyages

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1642-1650页

作者： zhi HUANG Zhao-bo CHEN Nan-qi REN Dong-xue HU Dong-huan zheng Zhen-peng ZHANG State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology Harbin 150090 China School of Materials Science & Chemical Engineering Harbin Engineering University Harbin 150001 China Institute of Environmental Science and Engineering Nanyang Technological University 637723 Singapore

To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.

关键词： CO2 removal O2 regeneration Solid amine water desorption (SAWD) Sabatier reactor Solid polymer electrolyte (SPE) Submarine

FBCRI Based Real-time Path Planning for Unmanned Aerial Vehicles in Unknown Environments with Uncertainty

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机器人 2013年第6期35卷 641-650页

作者： LIU Wei HAO peng zheng zheng CAI Kaiyuan School of Automation Science and Electrical Engineering Beihang University Science and Technology on Aircraft Control Laboratory High-Tech Institute of Xi'an

This paper presents an FBCRI(feedback based compositional rule of inference)based novel path planning method to satisfy the requirements of real-time navigation,smoothness optimization and probabilistic obstacle *** local path-searching behaviors in regional ranges and global goal-seeking behaviors in holistic ranges,the method infers behavior weights using fuzzy reasoning embedded with feedback,and then coordinates the behaviors to generate new reference *** view of the deterministic decisions and the uncertain states of a UAV(unmanned air vehicle),chance constraints are adopted to probabilistically guarantee the UAV’s safety at a required *** results in representative scenes prove that the method is able to rapidly generate convergent paths in obstacle-rich environments,as well as highly improve the path quality with respect to smoothness and probabilistic safety.

关键词： unmanned aerial vehicle path planning fuzzy reasoning FBCRI(feedback based compositional rule of inference) uncertainty

Towards“General Purpose”Brain-Inspired Computing System

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Tsinghua Science and Technology 2021年第5期26卷 664-673页

作者： Youhui Zhang peng Qu Weimin zheng the Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

Brain-inspired computing refers to computational models,methods,and systems,that are mainly inspired by the processing mode or structure of brain.A recent study proposed the concept of"neuromorphic completeness"and the corresponding system hierarchy,which is helpful to determine the capability boundary of brain-inspired computing system and to judge whether hardware and software of brain-inspired computing are compatible with each *** a position paper,this article analyzes the existing brain-inspired chips design characteristics and the current so-called"general purpose"application development frameworks for brain-inspired computing,as well as introduces the background and the potential of this ***,some key features of this concept are presented through the comparison with the Turing completeness and approximate computation,and the analyses of the relationship with"general-purpose"brain-inspired computing systems(it means that computing systems can support all computable applications).In the end,a promising technical approach to realize such computing systems is introduced,as well as the on-going research and the work *** believe that this work is conducive to the design of extensible neuromorphic complete hardware-primitives and the corresponding *** this basis,it is expected to gradually realize"general purpose"brain-inspired computing system,in order to take into account the functionality completeness and application efficiency.

关键词： brain-inspired computing neuromorphic computing computational completeness hardware/software decoupling system hierarchy

Structural features of 18R-type long-period stacking ordered phase in Mg85Zn6Y9 alloy and the Ni doping effect on its hydrogen storage properties

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Journal of Materials Science & Technology 2023年第14期145卷 148-155页

作者： zhiwen zheng Cong peng Qingan Zhang School of Materials Science and Engineering Anhui University of TechnologyMaanshanAnhui 243002China

Magnesium-based alloys with 18R-type long-period stacking ordered(LPSO)structures have attracted wide attention for structural and functional *** understand hydrogen storage properties of 18R phase,the Mg_(85)Zn_(6)Y_(9)alloy with 94 wt.%of 18R-type LPSO phase is prepared in this *** 18R phase has a layered structure where Y-Zn-Mg and Mg layers alternately stack along the *** the Y-Zn-Mg layers,Y,Zn and partial Mg sites are co-occupied by Y and Mg,Zn and Mg,and Mg and Zn/Y atoms,*** the 18R phase is easily decomposed intoα-MgH_(2),γ-MgH_(2),YH_(2),YH_(3),C14-type Laves phase MgZn_(2)and minor CsCl-type Y(Mg,Zn)during ball milling under hydrogen ***-ter further hydrogen absorption-desorption cycling,Y(Mg,Zn)disappears gradually and C14 phase trans-forms into C15-type Laves *** contrast,the Mg_(85)Zn_(6)Y_(9)alloy has better hydrogen storage kinetics and cycle durability than pure Mg because of the catalytic effect of YH_(2)/YH_(3)on hydrogen absorption-desorption and inhibition role of Laves phase in Mg crystallite ***,the introduction of Ni into Mg_(85)Zn_(6)Y_(9)sample leads to a further decrease in activation energy of hydrogen desorption from 106.39 to 96.78 kJ mol−1 due to the formation of Mg_(2)*** work not only provides new insights into structural features and hydrogen storage characteristics of 18R phase but offers an effective method for improving hydrogen storage properties.

关键词： Mg-based alloy Magnesium hydride Crystal structure Hydrogen storage

Experimental study on shear behavior of prestressed reactive powder concrete I-girders

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 618-627页

作者： Hui zheng zhi FANG Bin CHEN College of Civil Engineering Hunan University of TechnologyZhuzhou 412007China College of Civil Engineering Hunan UniversityChangsha 410082China

As a new generation of concrete,RPC(Reactive Powder Concrete)has attracted great research attention for its ultra-high strength and high *** the present paper,experimental results from tests on eight prestressed RPC I-section girders failing in shear are reported *** beams with RPC of 120 MPa in compression were designed to assess the ability to carry shear stress in thin webbed prestressed beams with *** test variables were the level of prestressing,shear span-depth ratio(a/d)and stirrup *** deformation,shear capacity and crack pattern were experimentally investigated in *** regard to the shear resistance of the test beams,the predictions from three standards(AFGC,JSCE and SIA)on the design of UHPC structures were compared with the experimental result suggesting that the experimental strength is almost always higher than ***,as a new concrete,was different from normal concrete and fiber reinforced *** study should be needed to develop an analytical method and computation model for shear strength of RPC beams.

关键词： prestressed concrete RPC(Reactive Powder Concrete) concrete beams shear strength experimental study