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An efficient and robust system for human following scenario using differential robot

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IET Cyber-Systems and Robotics 2024年第1期6卷 15-23页

作者： Jiangchao Zhu Changjia Ma chao Xu fei Gao College of Control Science and Engineering Zhejiang UniversityHangzhouChina

A novel system for human following using a differential robot,including an accurate 3‐D human position tracking module and a novel planning strategy that ensures safety and dynamic feasibility,is *** authors utilise a combination of gimbal camera and LiDAR for long‐term accurate human *** the planning module takes the target's future trajectory as a reference to generate a coarse path to ensure the following *** that,the trajectory is optimised considering other constraints and following *** demonstrate the robustness and efficiency of our system in complex environments,demonstrating its potential in various applications.

关键词： human‐robot interaction trajectory optimization visual tracking

Effects of Fe solid solute on grain boundaries of bi-crystal Cu: A molecular dynamics simulation

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Nano Materials Science 2024年第1期6卷 86-95页

作者： Shuohan Yang Hongwei bao Huizhong Bai Yan Li Haodong Xu fei Ma State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an710049ShaanxiChina

Grain boundaries(GBs)play a crucial role on the structural stability and mechanical properties of Cu and its *** this work,molecular dynamics(MD)simulations are employed to study the effects of Fe solutes on the formation energy,excess volume,dislocations and melting behaviors of GBs in CuFe *** is illustrated that Fe solute affects the structural stability of Cu GBs substantially,the formation energy of GBs is reduced,but the thickness and melting point of GBs are increased,that is,the structural stability of Cu GBs is significantly improved owing to the Fe solutes.A strong scaling law exists between the formation energy,excess volume,thickness and melting point of ***,Fe solid solute plays an important role in the characteristics of GBs in bi-crystal Cu.

关键词： CuFe alloy Grain boundary Structural stability MD simulations

Effect of rare earth on primary carbides in H13 die steel and their addition method:a review

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Journal of Iron and Steel Research International 2024年第3期31卷 531-551页

作者： Jing-feng Wang Lin-zhu Wang chao-yi Chen Xiang Wang fei Zhao School of Materials and Metallurgy Guizhou UniversityGuiyang 550025GuizhouChina Zhengzhou Railway Vocational and Technical College Zhengzhou 450000HenanChina Guizhou Provincial University Key Laboratory of High Performance Battery Materials Guizhou UniversityGuiyang 550025GuizhouChina Shougang Guiyang Special Steel Co. Guiyang 550005GuizhouChina

Larger-sized primary carbides lead to stress concentration during the application of H13 hot-work die steel,resulting in microcracks and fatigue *** earth was usually added to modify the carbides and *** existing literature is reviewed on the effect of rare earth on primary carbides in H13 steel.A comprehensive review on the effect of rare earth on the characteristics of primary carbides,i.e.,number,size,morphology,and thermal stability in H13 steel,was *** precipitation mechanism and nucleation of primary carbides with rare earth were *** position and form of rare earth in steel and their effects on alloying elements segregation were *** addition techniques of rare earth in H13 steel were compared,and the prospects for other uncommon rare earth and emerging technology were *** on the current references,it can be known that adding rare earth facilitated refined and dispersed primary *** size of primary carbides would be reduced,and their morphology would be improved because the rare earth inclusions formed in H13 steel can act as nucleation cores forγ-Fe orδ-Fe,refining the dendritic ***,the number of primary carbides at grain boundaries would be significantly ***,rare earth had little impact on thermal *** nucleation of primary carbides tended to be inhibited due to the modification of inclusions by rare earth which were likely to be nucleation cores for primary *** earth had been reported to affect the mechanism and process of primary carbide ***,the addition of rare earth can inhibit the segregation of alloying elements and carbon diffusion by ***,laboratory experiments and theoretical calcu-lations need to be conducted to study the states and evolution of rare earth steels.

关键词： Rare earth H13 die steel Primary carbide Nucleation Dendritic structure

Testing the first law of black hole mechanics with gravitational waves

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 76-82页

作者： chao-Wan-Zhen Wang Jin-bao Zhu Guo-Qing Huang Fu-Wen Shu Department of Physics Nanchang UniversityNanchang 330031China Center for Relativistic Astrophysics and High Energy Physics Nanchang UniversityNanchang 330031China GCAP-CASPER Physics DepartmentBaylor UniversityWaco 76798-7316USA

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe,particularly black *** this study,we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics,employing two different *** consider the secondary compact object as a perturbation to the primary black hole before the merger,and the remnant black hole as a stationary black hole after the *** the pre-merger and post-merger analysis,our results demonstrate consistency with the first law,with an error level of approximate 25%at a68%credibility level for *** the full inspiral-merger-ringdown analysis,our results show consistency with the first law of black hole mechanics,with an error level of about 6%at a 68%credibility level and 10%at a 95%credibility level for ***,we observe that the higher the mass ratio of the gravitational wave source,the more consistent our results are with the first law of black hole ***,our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

关键词： gravitational waves black hole mechanics data analysis ringdown

Effects of rare earth elements on inclusions, microstructure and impact toughness of spring steel

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Journal of Iron and Steel Research International 2024年第4期31卷 933-944页

作者： Chun-lei Hao chao-yun Yang Peng Liu Yi-kun Luan bao-guang Sang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina School of Mechanical Engineering and Automation Dalian Polytechnic UniversityDalian 116034LiaoningChina

Spring steel is an indispensable basic part manufacturing material in mechanical equipment,which is widely used in transportation tools such as automobiles,railways,construction machinery and other *** effects of rare earth(RE)on inclusions,microstructure,carbides and impact toughness of 50CrV spring steel were studied by means of optical microscope,scanning electron microscope,transmission electron microscope and impact *** results show that the addition of rare earth can modify the main MnS and Al_(2)O_(3) inclusions in steel to form spherical or near-spherical rare earth inclusions,and the size of inclusions is significantly *** the quenched structure,the size of martensite slab becomes smaller and the structure is *** tempering,the carbide changes from sheet to ellipse,which makes it easier for spring steel to form stress concentration cracks under *** becomes finer and more dispersed,which leads to better pinning of grain boundaries and smaller grain *** impact toughness of 50CrV-RE spring steel increased from 21 to 41 J by 95%due to the improvement of inclusions,microstructure and carbides by rare *** is possible to improve the strength and toughness of spring steel for the improvement of railway running speed and the development of vehicle lightweight in China.

关键词： Rare earth-Spring steel Inclusion Microstructure Impact toughness

The Consistency of LSE Estimators in Partial Linear Regression Models under Mixing Random Errors

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1244-1272页

作者： Yun bao YAO Yu Tan LÜ chao LU Wei WANG Xue Jun WANG School of Mathematical Sciences Anhui UniversityHefei 230601P.R.China School of Big Data and Artificial Intelligence Chizhou UniversityChizhou 247000P.R.China School of Big Data and Statistics Anhui UniversityHefei 230601P.R.China

In this paper,we consider the partial linear regression model y_(i)=x_(i)β^(*)+g(ti)+ε_(i),i=1,2,...,n,where(x_(i),ti)are known fixed design points,g(·)is an unknown function,andβ^(*)is an unknown parameter to be estimated,random errorsε_(i)are(α,β)-mix_(i)ng random *** p-th(p>1)mean consistency,strong consistency and complete consistency for least squares estimators ofβ^(*)and g(·)are investigated under some mild *** addition,a numerical simulation is carried out to study the finite sample performance of the theoretical ***,a real data analysis is provided to further verify the effect of the model.

关键词： (α,β)-mixing random variables partial linear regression model least squares estimator consistency

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

Tryptophan-specific peptide modification through metal-free photoinduced N-H alkylation employing N-aryl glycines

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Chinese Chemical Letters 2024年第6期35卷 316-319页

作者： Jianhui Yin Wenjing Huang Changyong Guo chao Liu fei Gao Honggang Hu School of Medicine or Institute of Translation Medicine Shanghai UniversityShanghai 200444China

Tryptophan(Trp)carries a unique heteroaromatic indole side chain and plays a critical role in peptide or protein ***,we have reported a metal-free photoinduced N-H alkylation strategy using N-aryl glycines for specific modification of tryptophan-containing *** robustness of our approach is demonstrated by its wide substrate scope,excellent isolated yields,as well as almost unobservable side *** this highly efficiently metal-free condition,alkylated Trp-containing peptides can be smoothly *** study provides a reliable and practical tool for the chemo-selective modification of various tryptophan containing oligopeptides.

关键词： Tryptophan Peptide Modification Glycine Photoinduced

Bone marrow mesenchymal stem cells in treatment of peripheral nerve injury

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World Journal of Stem Cells 2024年第8期16卷 799-810页

作者： Xiong-fei Zou bao-Zhong Zhang Wen-Wei Qian Florence Mei Cheng Department of Orthopedic Surgery Peking Union Medical College HospitalBeijing 100730China College of Nursing The Ohio State UniversityOhioOH 43210United States

Peripheral nerve injury(PNI)is a common neurological disorder and complete functional recovery is difficult to *** recent years,bone marrow mesenchymal stem cells(BMSCs)have emerged as ideal seed cells for PNI treatment due to their strong differentiation potential and autologous trans-plantation *** review aims to summarize the molecular mechanisms by which BMSCs mediate nerve repair in *** key mechanisms discussed include the differentiation of BMSCs into multiple types of nerve cells to promote repair of nerve *** also create a microenvironment suitable for neuronal survival and regeneration through the secretion of neurotrophic factors,extracellular matrix molecules,and adhesion ***,BMSCs release pro-angiogenic factors to promote the formation of new blood *** modulate cytokine expression and regulate macrophage polarization,leading to ***,BMSCs synthesize and release proteins related to myelin sheath formation and axonal regeneration,thereby promoting neuronal repair and ***,this review explores methods of applying BMSCs in PNI treatment,including direct cell trans-plantation into the injured neural tissue,implantation of BMSCs into nerve conduits providing support,and the application of genetically modified BMSCs,among *** findings confirm the potential of BMSCs in treating ***,with the development of this field,it is crucial to address issues related to BMSC therapy,including establishing standards for extracting,identifying,and cultivating BMSCs,as well as selecting application methods for BMSCs in PNI such as direct transplantation,tissue engineering,and genetic *** these issues will help translate current preclinical research results into clinical practice,providing new and effective treatment strategies for patients with PNI.

关键词： Bone marrow mesenchymal stem cells Peripheral nerve injury Schwann cells Myelin sheath Tissue engineering