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The influence of yttrium and manganese additions on the degradation and biocompatibility of magnesium-zinc-based alloys:In vitro and in vivo studies

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Journal of Magnesium and Alloys 2024年第2期12卷 608-624页

作者： Lei Shi Yang Yan Chun-sheng shao kun Yu Bo zhang Liang-jian Chen Third Xiangya Hospital Central South UniversityChangsha 410013China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China Department of Mechanical Engineering City University of Hong KongHong KongChina

The repair and regeneration of bone defects are highly challenging orthopedic ***,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human *** aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion *** this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a *** then investigated the effect of additions of Y and Mn on alloys'*** results show that Mn and Y can improve not only compression strength but also corrosion *** alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in *** degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or ***,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.

关键词： Magnesium alloy Biodegradation Biocompatibility Bone regeneration Bone defect repair

Structural evolution and high-temperature sensing performance of polymer-derived SiAlBCN ceramics

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Journal of Advanced Ceramics 2024年第4期13卷 478-485页

作者： Chao Ma kun Liu Pengfei shao Daoyang Han Kang Wang Mengmeng Yang Rui Zhao Hailong Wang Rui zhang Gang shao School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Zhongyuan Critical Metal Laboratory Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentZhengzhou UniversityZhengzhou 450002China

In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great ***,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical ***,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis *** microstructure evolution,high temperature sensing properties,and stability were investigated in *** results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing *** defect concentration displays a decreasing ***,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and ***,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.

关键词： polymer-derived SiAlBCN ceramics temperature sensor harsh environments oxidation and corrosion resistance

A Fair and Trusted Trading Scheme for Medical Data Based on Smart Contracts

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Computers, Materials & Continua 2024年第2期78卷 1843-1859页

作者： Xiaohui Yang kun zhang School of Cyber Security and Computer Hebei UniversityBaoding071000China

Data is regarded as a valuable asset,and sharing data is a prerequisite for fully exploiting the value of ***,the current medical data sharing scheme lacks a fair incentive mechanism,and the authenticity of data cannot be guaranteed,resulting in low enthusiasm of participants.A fair and trusted medical data trading scheme based on smart contracts is proposed,which aims to encourage participants to be honest and improve their enthusiasm for *** scheme uses zero-knowledge range proof for trusted verification,verifies the authenticity of the patient’s data and the specific attributes of the data before the transaction,and realizes privacy *** the same time,the game pricing strategy selects the best revenue strategy for all parties involved and realizes the fairness and incentive of the transaction *** smart contract is used to complete the verification and game bargaining process,and the blockchain is used as a distributed ledger to record the medical data transaction process to prevent data tampering and transaction ***,by deploying smart contracts on the Ethereum test network and conducting experiments and theoretical calculations,it is proved that the transaction scheme achieves trusted verification and fair bargaining while ensuring privacy protection in a decentralized *** experimental results show that the model improves the credibility and fairness of medical data transactions,maximizes social benefits,encourages more patients and medical institutions to participate in the circulation of medical data,and more fully taps the potential value of medical data.

关键词： Blockchain data transactions zero-knowledge proof game pricing

Elliptical encirclement control capable of reinforcing performances for UAVs around a dynamic target

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Defence Technology（防务技术） 2024年第2期32卷 104-119页

作者： Fei zhang Xingling shao Yi Xia Wendong zhang National Key Laboratory for Electronic Measurement Technology School of Instrument and ElectronicsNorth University of ChinaTaiyuan030051China

Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external ***,elliptical encirclement with a time-varying observation radius,may permit a more flexible and high-efficacy enclosing solution,whilst the non-orthogonal property between axial and tangential speed components,non-ignorable environmental perturbations,and strict assignment requirements empower elliptical encircling control to be more challenging,and the relevant investigations are still *** this line,an appointed-time elliptical encircling control rule capable of reinforcing circumnavigation performances is developed to enable Unmanned Aerial Vehicles(UAVs)to move along a specified elliptical path within a predetermined reaching *** remarkable merits of the designed strategy are that the relative distance controlling error can be guaranteed to evolve within specified regions with a designer-specified convergence ***,wind perturbations can be online counteracted based on an unknown system dynamics estimator(USDE)with only one regulating parameter and high computational *** tool demonstrates that all involved error variables are ultimately limited,and simulations are implemented to confirm the usability of the suggested control algorithm.

关键词： Elliptical encirclement Reinforced performances Wind perturbations UAVs

Distributed Multicircular Circumnavigation Control for UAVs with Desired Angular Spacing

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Defence Technology（防务技术） 2024年第1期31卷 429-446页

作者： Shixiong Li Xingling shao Wendong zhang Qingzhen zhang National Key Laboratory for Electronic Measurement Technology School of Instrument and ElectronicsNorth University of ChinaTaiyuan 030051China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100086China

This paper addresses a multicircular circumnavigation control for UAVs with desired angular spacing around a nonstationary *** defining a coordinated error relative to neighboring angular spacing,under the premise that target information is perfectly accessible by all nodes,a centralized circular enclosing control strategy is derived for multiple UAVs connected by an undirected graph to allow for formation behaviors concerning the moving ***,to avoid the requirement of target’s states being accessible for each UAV,fixed-time distributed observers are introduced to acquire the state estimates in a fixed-time sense,and the upper boundary of settling time can be determined offline irrespective of initial properties,greatly releasing the burdensome communication ***,with the aid of fixed-time distributed observers,a distributed circular circumnavigation controller is derived to force all UAVs to collaboratively evolve along the preset circles while keeping a desired angular *** is inferred from Lyapunov stability that all errors are demonstrated to be *** are offered to verify the utility of proposed protocol.

关键词： Angular spacing Distributed observer Multicircular circumnavigation Moving target UAVs

Multi-circular formation control with reinforced transient profiles for nonholonomic vehicles:A path-following framework

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Defence Technology（防务技术） 2024年第1期31卷 278-287页

作者： Jintao zhang Xingling shao Wendong zhang Zongyu Zuo School of Instrument and Electronics North University of ChinaTaiyuan 030051China State Key Laboratory of Dynamic Measurement Technology North University of ChinaTaiyuan 030051China Seventh Research Division School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100191China

This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular *** addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any *** significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient ***,all variables existing in the entire system are analyzed to be *** and experimental results are provided to validate the utility of suggested solution.

关键词： Multi-circular formation Reinforced transient profiles Nonholonomic vehicles Path following

A SIMPLE ITERATIVE ALGORITHM FOR MAXCUT

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Journal of Computational Mathematics 2024年第5期42卷 1277-1304页

作者： Sihong shao Dong zhang Weixi zhang CAPT LMAM and School of Mathematical SciencesPeking UniversityBeijing 100871China LMAM and School of Mathematical Sciences Peking UniversityBeijing 100871China

We propose a simple iterative(SI)algorithm for the maxcut problem through fully using an equivalent continuous *** does not need rounding at all and has advantages that all subproblems have explicit analytic solutions,the cut values are monotonically updated and the iteration points converge to a local optima in finite steps via an appropriate subgradient *** experiments on G-set demonstrate the *** particular,the ratios between the best cut values achieved by SI and those by some advanced combinatorial algorithms in[***.,248(2017),365-403]are at least 0.986 and can be further improved to at least 0.997 by a preliminary attempt to break out of local optima.

关键词： Maxcut Iterative algorithm Exact solution Subgradient selection Fractional programming

Mechanism of Ta on the microstructure and properties of Fe-Mn damping alloys

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Tungsten 2024年第4期6卷 767-777页

作者： Gui-Xiang Liu kun zhang Chao Han Xiao-Lin shao Jun Lu Lin zhang Xiao-Song Jiang Zi-Xuan Wu Liu Yang The Second Sub-Institute Nuclear Power Institute of China Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiao tong University School of Engineering and Materials Science Queen Mary University of London Institute for Applied Materials (IAM-WK) Karlsruhe Institute of Technology (KIT)

Fe-Mn-Co-xTa alloys（x=0,1,2,3 wt.%） were fabricated using spark plasma sintering to explore the influence of Ta content on the microstructure,mechanical properties,and damping characteristics of Fe-17Mn-3Co damping *** micro structural analysis reveals the dominant presence of γ-austenite,ε-martensite,α'-martensite,and Co3Ta precipitates within the *** increments in Ta content exhibit proportional enhancements in hardness,tensile strength,and fracture elongation of the ***,these improvements in mechanical attributes are closely correlated with the generated second-phase *** the Ta content increases,there is a gradual augmentation in the formation of Co3Ta within the ***,the damping property initially experiences an ascent followed by a subsequent decline with rising Ta *** damping behavior finds its origins in multiple mechanisms,including grain boundary damping stemming from reduced grain size,interfacial damping induced by the generated Co3Ta,and dislocation *** is noteworthy that the emergence of the secondary phase wields a dual impact on damping *** the one hand,the proliferation of the second phase fosters increased interfaces for energy *** the other hand,these interfaces give rise to compressive stresses,constraining interface movement and thus impeding damping property enhancement.

关键词： Damping Fe–Mn–Co Mechanical properties Spark plasma sintering Ta

Electrochemical radical-polar crossover:a radical approach to polar chemistry

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Science China Chemistry 2024年第2期67卷 450-470页

作者： Zhoumei Tan Haonan zhang kun Xu Chengchu Zeng Faculty of Environment and Life Beijing University of TechnologyBeijing100124China

Radical-polar crossover(RPC) reaction bridges the gap between one-and two-electron reactivities,thus providing an ideal solution to overcome the limitations of both radical and polar *** this manifold,organic electrochemistry provides a uniquely facile strategy to access a diverse array of radical intermediates,thus broadening the chemical space of the RPC *** review highlights the synthetic advances in the field of electrochemical RPC reactions since 2020,with an emphasis on the substrate scope,reaction limitation and mechanistic *** related RPC reactions are categorized as netoxidative,net-reductive,or redox neutral transformations.

关键词： electrosynthesis radical-polar crossover radical chemistry polar chemistry alkene functionalization