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Experimental investigation of junction growth of rough contacts using X-ray computed tomography

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Friction 2024年第11期12卷 2519-2531页

作者： Runliang WANG Jianhua liu bo liu Duo JIA Xiaoyu DING School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China AECC Shenyang Engine Research Institution Shenyang 110000China

The real contact area(RCA)of randomly rough contacts has received a great deal of attention because it correlates strongly with friction,lubrication,sealing,and *** have revealed that the RCA associated with deterministic normal squeezing loads increases when tangential loads are also applied,in a phenomenon called junction ***,experimental investigations of the junction growth of randomly rough contacts are ***,we used X-ray computed tomography(CT)to measure junction growth when two aluminum alloy surfaces were in contact.A high-resolution experimental setup was used to apply loads and observe contact behaviors at a resolution of 4μ*** RCA and average contact gaps were computed using a three-dimensional(3D)geometric model constructed from gray CT images using the Otsu thresholding *** results showed that the RCA increased as the normal load *** RCA increased by 22.67%after a tangential load was applied(junction growth),and the average gap decreased by 14.01%after a tangential load was ***,X-ray CT accurately measured the junction growth as a novel quantitative method.

关键词： three-dimensional(3D)contact analyses real contact area(RCA),junction growth X-ray computed tomography(CT) assembly interfaces

Effect and Mechanism of Rare Earth Hydrotalcite Inhibiting Coal Spontaneous Combustion

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 50-59页

作者：张小娟 liu bo 罗振敏 SUN Lu School of Safety Science and Engineering Xi’an University of Science and TechnologyXi’an 710054China

A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.

关键词： rare earth hydrotalcite coal spontaneous combustion mechanism

A Random Fusion of Mix 3D and Polar Mix to Improve Semantic Segmentation Performance in 3D Lidar Point Cloud

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 845-862页

作者： bo liu Li Feng Yufeng Chen School of Computer Science and Engineering Macao University of Science and TechnologyMacao999078China School of Computer Science and Artificial Intelligence Chaohu UniversityChaohu238000China Institute of Vehicle Information Control and Network Technology Hubei University of Automotive TechnologyShiyan442002China

This paper focuses on the effective utilization of data augmentation techniques for 3Dlidar point clouds to enhance the performance of neural network *** point clouds,which represent spatial information through a collection of 3D coordinates,have found wide-ranging *** augmentation has emerged as a potent solution to the challenges posed by limited labeled data and the need to enhance model generalization *** of the existing research is devoted to crafting novel data augmentation methods specifically for 3D lidar point ***,there has been a lack of focus on making the most of the numerous existing augmentation *** this deficiency,this research investigates the possibility of combining two fundamental data augmentation *** paper introduces PolarMix andMix3D,two commonly employed augmentation techniques,and presents a new approach,named *** of using a fixed or predetermined combination of augmentation methods,RandomFusion randomly chooses one method from a pool of options for each instance or *** innovative data augmentation technique randomly augments each point in the point cloud with either PolarMix or *** crux of this strategy is the random choice between PolarMix and Mix3Dfor the augmentation of each point within the point cloud data *** results of the experiments conducted validate the efficacy of the RandomFusion strategy in enhancing the performance of neural network models for 3D lidar point cloud semantic segmentation *** is achieved without compromising computational *** examining the potential of merging different augmentation techniques,the research contributes significantly to a more comprehensive understanding of how to utilize existing augmentation methods for 3D lidar point *** data augmentation technique offers a simple yet effective method to leverage the diversity of augmentation techniques and boost the ro

关键词： 3D lidar point cloud data augmentation RandomFusion semantic segmentation

Structure engineering of cathode host materials for Li-S batteries

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Rare Metals 2024年第4期43卷 1370-1389页

作者： Jia-Jun Long Hua Yu Wen-bo liu School of New Energy and Materials Southwest Petroleum UniversityChengdu610500China School of Mechanical Engineering Sichuan UniversityChengdu610065China

Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its *** challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode *** the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned *** this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and ***,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in ***,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.

关键词： Lithium-sulfur batteries Structure engineering Cathode Host materials

Development of a high-repetition-rate lumped-inductance kicker magnet prototype for the beam switchyard of SHINE

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Nuclear Science and Techniques 2024年第2期35卷 20-31页

作者： Yong-Fang liu Rui-Ping Wang Jin Tong bo Zhang Si Chen Qi-Bing Yuan Hai-Xiao Deng Ming Gu bo liu Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201412People’s Republic of China

The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 *** magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch *** kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn *** full magnetic field strength was 0.005 *** paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker *** relevant experimental results are also *** pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 *** developed kicker satisfies the requirements for the SHINE ***,numerous recommendations for the future optimization of kicker magnets are provided.

关键词： X-ray free-electron laser Kicker magnet Beam switchyard High repetition rate Ni-Zn ferrites

Investigation of control effects of end-wall selfadaptive jet on three-dimensional corner separation of a highly loaded compressor cascade

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Chinese Journal of Aeronautics 2024年第6期37卷 109-126页

作者： Hejian WANG bo liu Xiaochen MAO botao ZHANG Zonghao YANG School of Power and Energy Northwestern Polytechnical UniversityXi’an 710129China The National Key Laboratory of Science and Technology on Aerodynamic Design and Research Xi’an 710129China Taihang Laboratory Chengdu 610000China

To overcome the limitations posed by three-dimensional corner separation,this paper proposes a novel flow control technology known as passive End-Wall(EW)self-adaptive *** single EW slotted schemes(EWS1 and EWS2),alongside a combined(COM)scheme featuring double EW slots,were *** results reveal that the EW slot,driven by pressure differentials between the pressure and suction sides,can generate an adaptive jet with escalating velocity as the operational load *** high-speed jet effectively re-excites the local low-energy fluid,thereby mitigating the corner ***,the EWS1 slot,positioned near the blade leading edge,exhibits relatively low jet velocities at negative incidence angles,causing jet separation and exacerbating the corner ***,the EWS2 slot is close to the blade trailing edge,resulting in massive low-energy fluid accumulating and separating before the slot outlet at positive incidence *** contrast,the COM scheme emerges as the most effective solution for comprehensive corner separation *** can significantly reduce the total pressure loss and improve the static pressure coefficient for the ORI blade at 0°-4° incidence angles,while causing minimal negative impact on the aerodynamic performance at negative incidence ***,the corner stall is delayed,and the available incidence angle range is broadened from -10°--2°to -10°-4°.This holds substantial promise for advancing the aerodynamic performance,operational stability,and load capacity of future highly loaded compressors.

关键词： Three-dimensional corner separation End-wall adaptive jet Total pressure loss Highly loaded compressor cascade Compressors

Design strategy and relevant flow mechanisms of highly loaded 3D compressor tandem cascades

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Chinese Journal of Aeronautics 2024年第7期37卷 220-235页

作者： Xiaochen MAO Yunyu WANG Zhihua DING Hao CHENG bo liu School of Power and Energy Northwestern Polytechnical UniversityXi’an 710129China The National Key Laboratory of Science and Technology on Aerodynamic Design and Research Xi’an 710129China Xi’an Thermal Power Research Institute Co.Ltd Xi’an 710072China

To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed from multiple perspectives *** results show that the interference effects on the Front Blade(FB)and Rear Blade(RB)should not be overlooked during the design phase,and the design strategies at the midspan and endwall are completely *** the midspan,the optimization aims to increase the interference effects and the strength of the gap jet while maintaining the same load on the FB and ***,the endwall optimal airfoil exhibits weakening interference effects,advancement of the gap jet location,and load transfer from the FB to *** further analysis of flow characteristics,the midspan optimal airfoil is beneficial for inhibiting the low-energy fluid from interacting with the suction surface of RB under the design condition,but results in earlier occurrence of corner *** endwall optimal airfoil helps suppress the development of the secondary flow and delay the onset of corner ***,by combining the benefits of these two design approaches,additional forward sweep effects are achieved,further enhancing the performance of the tandem cascade.

关键词： Tandem cascade Interference effect Vortex structure Load split Compressor

Complicated flow in tip flow field of a compressor tandem cascade using delayed detached eddy simulation

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Chinese Journal of Aeronautics 2024年第8期37卷 63-78页

作者： botao ZHANG Xiaochen MAO bo liu Hejian WANG Zonghao YANG School of Power and Energy Northwestern Polytechnical UniversityXi’an 710129China Taihang Laboratory Chengdu 610000China

The complex flow characteristics in the tip region of a tandem cascade with tip clearance have been calculated and analyzed using Delayed Detached Eddy Simulation(DDES).The coherent mechanism of the vortex structures near the blade tip was discussed,and the unsteady behaviors and features in the tip flow field were ***,the interaction between the tip leakage flow and the gap jet was *** results show that,compared to the datum cascade,the blade tip load of the rear blade increases while that of the front blade *** fluctuations of the tandem cascade are mainly caused by the interaction between the tip leakage flow and gap jet,and by the mixing of the vortex structures,but there is no essential change in the spectrum feature of the tip leakage ***,a detailed analysis of the development of vortices in the tip region is conducted by the topological structures of the flow *** with the three-dimensional vortex structures,the schematic diagram of the vortex system of the datum single-row cascade and tandem cascade is summarized.

关键词： Tandem cascade Tip leakage flow Delayed Detached Eddy Simulation(DDES) Unsteady flow Gap jet Topological structure

Recovery of Li, Ni, Co and Mn from spent lithium-ion batteries assisted by organic acids: Process optimization and leaching mechanism

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 518-530页

作者： liuyi Ren bo liu Shenxu Bao Wei Ding Yimin Zhang Xiaochuan Hou Chao Lin bo Chen School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Zhejiang New Era Zhongneng Recycling Technology Co. LtdShaoxing 312000China Shenzhen Water Planning&Design Institute Co. LtdShenzhen 518000China

The proper recycling of spent lithium-ion batteries(LIBs)can promote the recovery and utilization of valuable resources,while also negative environmental effects resulting from the presence of toxic and hazardous *** this study,a new environmentally friendly hydro-metallurgical process was proposed for leaching lithium(Li),nickel(Ni),cobalt(Co),and manganese(Mn)from spent LIBs using sulfuric acid with citric acid as a *** effects of the concentration of sulfuric acid,the leaching temperature,the leaching time,the solid-liquid ratio,and the reducing agent dosage on the leaching behavior of the above elements were *** parameters were optimized using response surface methodology(RSM)to maximize the recovery of metals from spent *** maxim-um recovery efficiencies of Li,Ni,Co,and Mn can reach 99.08%,98.76%,98.33%,and 97.63%.under the optimized conditions(the sulfuric acid concentration was 1.16 mol/L,the citric acid dosage was 15wt%,the solid-liquid ratio was 40 g/L,and the temperature was 83℃ for 120 min),*** was found that in the collaborative leaching process of sulfuric acid and citric acid,the citric acid initially provided strong reducing CO_(2)^(-),and the transition metal ions in the high state underwent a reduction reaction to produce transition metal ions in the low ***,citric acid can also act as a proton donor and chelate with lower-priced transition metal ions,thus speeding up the dissolution process.

关键词： spent lithium-ion batteries leaching response surface methodology sulfuric acid citric acid