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Enhancing adhesive bond strength of CFRP/titanium joints through NaOH anodising and resin pre-coating treatments with optimised anodising conditions

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Chinese Journal of Aeronautics 2024年第2期37卷 511-523页

作者： Yunsen HU Jingheng zhang lin WANG Fei CHENG Xiaozhi HU School of Materials and Chemistry Southwest University of Science and TechnologyMianyang 621000China School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Engineering Research Center of Biomass Materials Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China Department of Mechanical Engineering University of Western AustraliaPerthWA 6009Australia

Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical *** study utilised NaOH anodising method to create micro-rough titanium surfaces for enhancing adhesive bonding between titanium alloy and CFRP laminates.A special and simple technique named Resin Pre-Coating(RPC)was also employed to improve the surface wetting of anodised titanium and grinded CFRP *** influences of anodising temperature and duration on the surface morphology,wettability and adhesive bond strength were *** single lap shear test results showed that the bond strength of specimens anodised at 20℃for 15 min improved by 135.9%and 95.4%,respectively,in comparison with that of acid pickled and grinded specimens(without RPC treatment).Although increasing the anodising temperature and duration produced rougher titanium surfaces,the adhesively bonded joints were not strong enough due to relatively friable titanium oxide layers.

关键词： Carbon Fibre Reinforced Polymer(CFRP) Titanium alloy Anodising Resin pre-coating Adhesive joints

Process intensification for the synthesis and purification of battery-grade Li_(2)CO_(3)with microfluidics

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Particuology 2024年第7期90卷 106-117页

作者： Haodu Li Jie zhang lin Dai Le Du Jiqin Zhu The State Key Laboratory of Chemical Resource Engineering College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China

Battery-grade lithium carbonate(Li_(2)CO_(3))with a purity of higher than 99.5 wt%is of great importance as a high value-added lithium ***,influences of different reaction systems and process control on product purity remain ***,a membrane dispersion microreactor was used to enhance the mass transfer of preparation and purification processes in homogeneous and heterogeneous *** systems of Na_(2)CO_(3)–LiCl,NH_(4)HCO_(3)–LiCl,and NH_(3)·H_(2)O−CO_(2)−LiCl,CO_(2)purification based on carbonation and decomposition were *** Li_(2)CO_(3)purity was increased by the improvement of mixing *** carbonation time was reduced by 62.5%and 58.3%for the NH_(3)·H_(2)O−CO_(2)and CO_(2)purification systems,*** the two ammonia-based systems,Li_(2)CO_(3)particles with a purity of 99.7–99.8 wt%were one-step prepared with a size of 3–5μm,which also met the requirement of the battery-grade *** purity was further increased to 99.9 wt%by CO_(2)purification and LiHCO_(3)*** investigation could provide a feasible alternative for the controllable preparation of battery-grade Li_(2)CO_(3)in one or multiple steps.

关键词： Microfluidics Battery grade Li_(2)CO_(3) Process intensification High purity

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

Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

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Journal of Thermal Science 2024年第3期33卷 1148-1160页

作者： zhang Yu CHEN Xiaoyan MIAO lin CHEN Liang HOU Yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Beijing Aerospace Technology Institute Beijing100083China

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.

关键词： hybrid heat sink impingement microchannel thermal management high heat flux

Deformation and Locomotion of Untethered Small-Scale Magnetic Soft Robotic Turtle with Programmable Magnetization

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Journal of Bionic Engineering 2024年第2期21卷 754-763页

作者： lin Xu Liu Yang Tao Li Xingbang zhang Jianning Ding School of Mechanical Engineering Jiangsu UniversityZhenjiang212013China The Key Laboratory of Bionic Engineering(Ministry of Education) Jilin UniversityChangchun130012China Shanghai Tianchun Technology Co. LtdShanghai201802China School of Mechanical Engineering Yangzhou UniversityYangzhou225009China

Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve biomimetic locomotion patterns such as straight-line swimming and turning *** soft robotic turtle(12.50 mm in length and 0.24 g in weight)is integrated with an Ecoflex-based torso and four magnetically programmed acrylic elastomer VHB-based limbs containing samarium-iron–nitrogen particles,and was able to carry a load more than twice its own *** to the limb locomotion characteristics of sea turtles,the magnetic torque causes the four limbs to mimic sinusoidal bending deformation under the influence of an external magnetic field,so that the turtle swims continuously ***,when the bending deformation magnitudes of its left and right limbs differ,the soft robotic turtle switches from straight-line to turning swimming at 6.334 rad/***,the tracking swimming activities of the soft robotic turtle along specific planned paths,such as square-shaped,S-shaped,and double U-shaped maze,is anticipated to be utilized for special detection and targeted drug delivery,among other applications owing to its superior remote directional control ability.

关键词： Magnetic soft robotic turtle Programmable magnetization Untethered soft robotics Bending deformation

A CAD-BEM geometry transformation method for face-based primary geometric input based on closed contour recognition

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Building Simulation 2024年第2期17卷 335-354页

作者： Jun Xiao Hao Zhou Shiji Yang Deyin zhang Borong lin Department of Building Science School of ArchitectureTsinghua UniversityBeijing100084China Key Laboratory of Eco Planning&Green Building Ministry of EducationTsinghua UniversityBeijing100084China Institute for Urban Governance and Sustainable Development Tsinghua UniversityBeijing100084China

Performance analysis during the early design stage can significantly reduce building energy ***,it is difficult to transform computer-aided design(CAD)models into building energy models(BEM)to optimize building *** model structures for CAD and BEM are *** this study,geometry transformation methods was implemented in BES tools for the early design stage,including auto space generation(ASG)method based on closed contour recognition(CCR)and space boundary topology calculation *** program is developed based on modeling tools SketchUp to support the CAD format(like*.stl,*.dwg,*.ifc,etc.).It transforms face-based geometric information into a zone-based tree structure model that meets the geometric requirements of a single-zone BES combined with the other thermal parameter inputs of the *** addition,this study provided a space topology calculation method based on a single-zone BEM *** program was developed based on the SketchUp modeling tool to support additional CAD formats(such as*.stl,*.dwg,*.ifc),which can then be imported and transformed into*.*** to current methods mostly focused on BIM-BEM transformation,this method can ensure more modeling *** method was integrated into a performance analysis tool termed MOOSAS and compared with the current version of the transformation *** were tested on a dataset comprising 36 conceptual models without partitions and six real cases with detailed *** ensures a transformation rate of two times in any bad model condition and costs only 1/5 of the time required to calculate each room compared to the previous version.

关键词： geometry transformation building energy model computer aid design closed contour recognition

Equivalent Impedance Parameter Calculation of Three-phase Symmetrical Loads for Harmonic Source Location

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 251-260页

作者： Yi zhang Bijie Liu Caihua lin Zhenguo Shao Yuncong Xu the Department of Electrical Engineering and Automation Fuzhou UniversityFuzhouChina State Grid Fujian Electric Power Research Institute FuzhouChina

The equivalent impedance parameters of loads have been widely used to identify and locate the harmonic ***,the existing calculation methods suffer from outliers caused by the zero-crossing of the *** outliers can result in inaccuracy and unreliability of harmonic source *** address this issue,this paper proposes an innovative method of equivalent impedance parameter calculation of three-phase symmetrical loads that avoid *** correctness and effectiveness of the proposed method are verified by simulations on Simulink using actual monitoring *** results show that the proposed method is not only simple and easy to implement but also highly accurate.

关键词： abc-αβtransformation equivalent impedance parameters of load harmonic source location nonlinear load power quality

A credibility-aware swarm-federated deep learning framework in internet of vehicles

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Digital Communications and Networks 2024年第1期10卷 150-157页

作者： Zhe Wang Xinhang Li Tianhao Wu Chen Xu lin zhang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China

Although Federated Deep Learning(FDL)enables distributed machine learning in the Internet of Vehicles(IoV),it requires multiple clients to upload model parameters,thus still existing unavoidable communication overhead and data privacy *** recently proposed Swarm Learning(SL)provides a decentralized machine learning approach for unit edge computing and blockchain-based coordination.A Swarm-Federated Deep Learning framework in the IoV system(IoV-SFDL)that integrates SL into the FDL framework is proposed in this *** IoV-SFDL organizes vehicles to generate local SL models with adjacent vehicles based on the blockchain empowered SL,then aggregates the global FDL model among different SL groups with a credibility weights prediction *** experimental results show that compared with the baseline frameworks,the proposed IoV-SFDL framework reduces the overhead of client-to-server communication by 16.72%,while the model performance improves by about 5.02%for the same training iterations.

关键词： Swarm learning Federated deep learning Internet of vehicles Privacy Efficiency

Closed-form solution to the dynamic programming for a heavy-duty parallel hybrid vehicle energy management

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Journal of Control and Decision 2024年第1期11卷 107-116页

作者： Tao zhang Zhongjun Yu Huangda lin National Key Laboratory for Vessel Integrated Power System Technology Naval University of EngineeringWuhanPeople’s Republic of China

Dynamic programming(DP)is frequently used to obtain the optimal solution to the hybrid electric vehicle(HEV)energy *** trade-off between the accuracy and the computational effort is the biggest problem for the DP *** closed-form solution to the DP is proposed to solve this ***,the affine linear model of the engine fuel rate is obtained based on engine test *** piecewise linear approximation of the motor power demand is obtained considering the different energy flows in the charging and discharging stages of the ***,the second-order Taylor expansion for the cost matrix at each time and state grid point is introduced to get the closed-form solution of the optimal torque *** results show that this method can greatly reduce the computing burden by 93%while ensuring near-optimal fuel economy compared with the conventional DP method.

关键词： Dynamic programming energy management closed-form solutions fuel economy hybrid electric vehicles