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月球南极尘埃等离子体环境特性

物理学报 2024年第15期73卷 133-140页

作者：李梦谣夏清蔡明辉杨涛许亮亮贾鑫禹韩建伟中国科学院国家空间科学中心空间天气国家重点实验室北京100190 中国科学院大学电子电气与通信工程学院北京100049 中国科学院大学天文与空间科学学院北京100049

由于缺少大气和全球性磁场的保护,空间等离子体环境可直接作用于月球表面的月壤层,月壤中较小粒径的月尘带电后会在月面附近形成复杂的尘埃等离子体环境,影响探月任务的顺利实施.针对月球南极尘埃等离子体环境,本文利用SPIS(spacecraft ... 详细信息

由于缺少大气和全球性磁场的保护,空间等离子体环境可直接作用于月球表面的月壤层,月壤中较小粒径的月尘带电后会在月面附近形成复杂的尘埃等离子体环境,影响探月任务的顺利实施.针对月球南极尘埃等离子体环境,本文利用SPIS(spacecraft plasma interactions software)软件,仿真研究了月球南极0—200 m高度范围的等离子体和月尘的空间分布情况及月面充电特性,揭示了月面附近尘埃等离子体环境特征及悬浮在月面附近的带电月尘对等离子体环境的影响.仿真结果与Apollo探测数据和Popel团队的理论数据吻合.研究结果:表明空间电位随着高度升高而增加,月球南极附近0—10 m电位约为–40 V,在100 m处空间电位约为–20 V;在10 m以下高度范围内月尘密度为10^(7.22)—10^(4.66) m^(–3);月表附近尘埃等离子体中的电子密度为10^(5.47) m^(–3),离子密度为10^(6.07) m–3,并随着高度升高而增大;带电月尘会影响月尘的空间分布,主要是通过影响空间电场的分布,进而导致电子分布差异,对离子的影响不大.

关键词：月球南极尘埃等离子体环境 SPIS 仿真月面电位分布

Real Heat Flux Analysis of Continuously Casting Round Billet

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Journal of Iron and Steel Research International 2008年第1期15卷 25-29页

作者： ZHAN Hui-ying WANG xu-dong GUO liang-liang YAO Man School of Material Science and Engineering Dalian University of Technology Dalian 116024 Liaoning China

The distributions of heat flux along the height and the circumferential direction of round billet mould were measured *** influence of casting speed,carbon content,powder,and pouring temperature on the average longitudinal and circumferential heat flux in the ＂high heat flux region＂ was *** experimental and analytical results provide a basis for an intelligent mould with online detection of defects,adjustment of operational parameters,optimization of the monitoring system,and even prediction of abnormal heat transfer.

关键词： continuous casting mould heat flux round billet

HgaNets:Fusion of Visual Data and Skeletal Heatmap for Human Gesture Action Recognition

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Computers, Materials & Continua 2024年第4期79卷 1089-1103页

作者： Wuyan liang Xiaolong xu School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210023China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing210023China

Recognition of human gesture actions is a challenging issue due to the complex patterns in both visual andskeletal features. Existing gesture action recognition (GAR) methods typically analyze visual and skeletal data,failing to meet the demands of various scenarios. Furthermore, multi-modal approaches lack the versatility toefficiently process both uniformand disparate input ***, in this paper, an attention-enhanced pseudo-3Dresidual model is proposed to address the GAR problem, called HgaNets. This model comprises two independentcomponents designed formodeling visual RGB (red, green and blue) images and 3Dskeletal heatmaps, *** specifically, each component consists of two main parts: 1) a multi-dimensional attention module forcapturing important spatial, temporal and feature information in human gestures;2) a spatiotemporal convolutionmodule that utilizes pseudo-3D residual convolution to characterize spatiotemporal features of gestures. Then,the output weights of the two components are fused to generate the recognition results. Finally, we conductedexperiments on four datasets to assess the efficiency of the proposed model. The results show that the accuracy onfour datasets reaches 85.40%, 91.91%, 94.70%, and 95.30%, respectively, as well as the inference time is 0.54 s andthe parameters is 2.74M. These findings highlight that the proposed model outperforms other existing approachesin terms of recognition accuracy.

关键词： Gesture action recognition multi-dimensional attention pseudo-3D skeletal heatmap

An Anisotropic Biomimetic Lemongrass Flexible Piezoelectric Actuator-Inhibitory Regression

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Journal of Bionic Engineering 2024年第4期21卷 1817-1829页

作者： Tianwei liang Yunhong liang Jiru Wang Hu Huang Zhi xu Hongwei Zhao Key Laboratory of CNC Equipment Reliability Ministry of EducationJilin UniversityChangchun130022China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130022China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang110167China The Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun130025China

At present,the existing piezoelectric stick-slip actuators have an inherent back-slip problem,which greatly limits the development and application of stick-slip *** order to inhibit the regression phenomenon,a new bionic lemongrass stickslip actuator was prepared by using polymer PDMS to replicate natural biological *** surface microstructure of the grass was copied by PDMS,and the PDMS film was *** rigid and flexible bionic friction pair was further prepared,and the flexible anisotropic PDMS stick slip actuator was *** was found that the anisotropic friction characteristics of the surface microstructure of the grass inhibited the anti-sliding motion,and the elastic potential energy of the PDMS film improved the output characteristics of the *** adjusting the input voltage to control the contact between the drive foot and the rotor,the rigid and flexible hybrid drive can be realized and the backsliding phenomenon can be *** actuator is compact,lightweight and can achieve high speed and high resolution output without preloading force,which has important application value in the field of fast and accurate positioning with load limitation.

关键词： Piezoelectric actuator Bionic surface Friction Surface friction Flexible film

Modeling and analysis of air combustion and steam regeneration in methanol to olefins processes

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Chinese Journal of Chemical Engineering 2024年第2期66卷 94-103页

作者： Jinqiang liang Danzhu Liu Shuliang xu Mao Ye Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China National Engineering Research Center of Lower-Carbon Catalysis Technology Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116021China University of Chinese Academy of Sciences Beijing 100049China

Light olefins is the incredibly important materials in chemical *** to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past ***,the catalyst deactivation is an inevitable feature in MTO processes,and regeneration,therefore,is one of the key steps in industrial MTO *** the MTO catalyst is regenerated by removing the deposited coke via air combustion,which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization *** study shows that the coke species over MTO catalyst can be regenerated via steam,which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas,is a promising pathway for further MTO processes *** this work,we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology *** shown,the steam regeneration could achieve a carbon utilization efficiency of 84.31%,compared to 74.74%for air combustion *** MTO processes using steam regeneration can essentially achieve the near-zero carbon *** addition,light olefins production of the MTO processes using steam regeneration is 12.81%higher than that using air combustion *** this regard,steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes,showing not only great environmental benefits but also competitive economic performance.

关键词： Model Methanol to olefins Regeneration Greenhouse gas Processes simulation

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

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China Ocean Engineering 2024年第2期38卷 297-312页

作者： ZHANG Yi CHEN Yue YUN Lai liang xu Ocean College Zhejiang UniversityZhoushan 316000China Hainan Institute Zhejiang UniversitySanya 572000China

This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of *** cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress *** suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical *** static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical *** is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 *** simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich ***,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried *** to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich *** has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell ***,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells.

关键词： bio-inspiration bidirectional corrugation sandwich shell external pressure buckling

A review of in situ carbon mineralization in basalt

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1467-1485页

作者： Xiaomin Cao Qi Li liang xu Yongsheng Tan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon *** storage is considered a reliable option for long-term carbon *** rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as ***,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage *** different reaction conditions,the carbonation products and carbonation rates *** mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt *** this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively *** assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling *** in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also *** study could provide insight into challenges as well as perspectives for future research.

关键词： Carbon mineralization Basalt CO_(2)-fluid-basalt interaction Petrophysical evolution Mechanical response Carbon capture and storage(CCS)

Magnetic and luminescent properties of bifunctional composite Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+)

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Journal of Rare Earths 2024年第8期42卷 1568-1576,I0006页

作者： Zhiqi liang Zhili Zhang Liu Li Wen xu Decai Li School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing100044China State Key Laboratory of Tribology Tsinghua UniversityBeijing100084China

As a kind of non-destructive testing method,magnetic particle inspection is widely used in the fields of aviation and high-speed *** properties of magnetic fluorescent bifunctional composites,such as fluorescence intensity and magnetic properties,have increasing demands in magnetic particle *** earth compounds offer potential as novel materials for fluorescent magnetic bifunctional composites due to their excellent optical properties and extremely narrow emission *** this work,the rare earth fluorescent material Y_(2)O_(2)S:Eu^(3+) was synthesized by solid-state reaction ***_(3)O_(4)nanoparticles prepared by hydrothermal method were uniformly coated on the Y_(2)O_(2)S:Eu^(3+) particles through physical adsorption of *** obtained Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) exhibits dark red color under the ultraviolet *** additio n,X-ray diffractio n,morphology,photoluminescence and hyste resis loop of Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) were *** luminescence mechanism of Y_(2)O_(2)S:Eu^(3+) is described in detail Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) displays good paramagnetism and has a good controllability under a magnetic *** magnetic particle inspection of Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) was performed using a 4-pole electromagnet and a test piece *** magnetic fluorescent bifunctional composite presented in this work can be applied for non-destructive testing.

关键词： Bifunctional material Fe_(3)O_(4) Y_(2)O_(2)S:Eu^(3+) Luminescence Solid-state reaction Rare earths

Recovery of rare earth elements from rare earth molten salt electrolytic slag via fluorine fixation by MgCl_(2)roasting

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Journal of Rare Earths 2024年第10期42卷 1979-1987页

作者： Minghui Zhang Bingxuan He Yinliang Liu Luewei xu Yong liang Faculty of Metallurgical Engineering Jiangxi University of Science and TechnologyGanzhou341000China Key Laboratory of lonic Rare Earth Resources and Environment Ministry of Natural ResourcesGanzhou3410ooChina Jiangxi Provincial Key Laboratory of Green and Low Carbon Metallurgy for Strategic Nonferrous Metals Ganzhou3410ooChina

Rare earth fluoride molten-salt electrolytic slag(REFES)is a precious rare earth element(REE)secondary resource,and conside rable amounts of REEs exist in REFES as REF_(3);they are difficult to dissolve in acid or water and impede efficient REE *** REFES recovery,the REF_(3)species in REFES are usually transformed into acid-soluble rare earth compounds by NaOH roasting or sulfating roasting and then extracted by acid leaching,Moreover,the fluorides in REFES are released as HF gas in the roasting process or enter the liquid phase during the water washing process;both of these processes cause fluorine *** the fluorine into the solid slag provides a way to avoid fluorine *** this study,a novel method was proposed to extract REEs from REFES via MgCl_(2)roasting followed by HCl *** calculations and the rmogravimetry-differential thermal analyses(TG-DTA)were conducted to investigate the reactions occurring in the roasting process,First,MgCl_(2)reacts with the REF_3and RE_(2)O_(3)to form RECl_(3)and REOCl,***,the RECI_(3)absorbs water and forms RE(OH)_(3).Third,MgCl_(2)·6H_(2)O is gradually dehydrated to MgCl_(2)·2H_(2)O and reacts with REF_(3)and RE(OH)_(3),and REOCl,MgF_(2)and MgO are *** HCl leaching,the REOCl in the roasting products is leached by HCl acid,while fluoride re mains in the solid slag as MgF_*** optimum experimental conditions are as follows:mass ratio of MgCl_(2)to REFES of 30%,roasting temperature of 700℃,roasting time of 2 h,hydrochloride acid concentration of 4 mol/L,leaching time of 2 h,leaching temperature of 90℃and leaching L/S ratio of 20:*** efficiencies for total leaching of the REEs,La,Ce,Pr,and Nd are 99.13%,99.20%,98.42%,99.38%,and 99.08%,***,the concentration of fluoride in the leaching solution is 2.191×10^(-6)mol/*** method has a short process flow with low reagent costs,and the problem of fluoride pollution from REFES recovery is solved;

关键词： Rare earths Molten-salt electrolytic slag Fluorine Recovery Leaching