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Enhancing the anti-corrosion performance and biocompatibility of AZ91D Mg alloy by applying roughness pretreatment and coating with in-situ Mg(OH)_(2)/Mg-Al LDH

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Journal of Magnesium and Alloys 2024年第6期12卷 2520-2533页

作者： Zexi Shao Pubo Li chao Zhang Bintao wu Chan Tang Mangmang Gao School of Materials and New Energy Ningxia Key Laboratory of Photovoltaic MaterialsNingxia UniversityYinchuan750021PR China Department of Gastroenterology The Third Xiangya HospitalCentral South UniversityChangsha410000PR China

Corrosion-resistant and biocompatible films were fabricated on AZ91D Mg alloy substrates by varying their roughness levels using met-allographic preparation and subsequent hydrothermal *** coated films comprised a mixed structure of Mg(OH)_(2)and Mg-Al layered double hydroxides(LDH)and exhibited excellent *** film thickness increased with decreasing surface *** resistance was evaluated using potentiodynamic polarization and electrochemical impedance *** pretreat-ment influenced the chemical activity of the Mg alloy surface and helped modulate the dissolution rate of the Mg_(17)Al_(12)phase during the hydrothermal *** decreasing roughness of the Mg substrate,the Al^(3+)concentration gradually increased,accelerating the in-situ formation of the Mg(OH)_(2)/LDH composite coating and improving its crystallinity.A thick and dense Mg(OH)_(2)/LDH coating was synthesized on the Mg substrate with the least roughness,substantially improving the corrosion resistance of the AZ91D *** lowest corrosion current density((5.73±2.75)×10^(−8)A·cm^(−2))was achieved,which was approximately three orders of magnitude less than that of bare ***,the coating demonstrated biocompatibility with no evident cytotoxicity,cellular damage,and hemolytic *** study provides an effective method for preparing coatings on Mg alloy surfaces with excellent corrosion resistance and biocompatibility.

关键词： Magnesium alloy Roughness Corrosion resistance Layered double hydroxides Biocompatibility

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Predesigned covalent organic framework with sulfur coordination: Anchoring Au nanoparticles for sensitive colorimetric detection of Hg(Ⅱ)

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Chinese Chemical Letters 2024年第5期35卷 392-396页

作者： Guorong Li Yijing wu chao Zhong Yixin Yang Zian Lin Ministry of Education Key Laboratory of Analytical Science for Food Safety and Biology Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food SafetyCollege of ChemistryFuzhou UniversityFuzhou 350108China

Targeted construction of new covalent organic frameworks(COFs)with specific purposes and rationalities to build colorimetric assay platform for environmental pollutant monitoring have attracted increasing ***,it is still challenging due to lack of available coordination sites inside COFs pores and only a slight bonding ability for anchoring *** this work,a two-dimensional(2D)COFs(termed as Tz-COF)with high crystallinity,excellent chemical stability,and abundant sulfur coordination in its skeletons was synthesized and used for the confined growth of Au *** was found that the Au NPs showed significant dispersibility for the support of *** proposed Tz-COF@Au NPs possessed outstanding Hg^(2+)-activated peroxidase-like activity benefited from physicochemical properties of gold amalgam and synergistic effect between COFs and Au NPs to oxidize chromogenic *** on highly efficient activity and distinctive color evolution,the strategy for detecting Hg^(2+)was developed and successfully applied to determine the content of Hg^(2+)in real environmental *** work manifests that a potential strategy to establish a colorimetric assay platform for environmental pollutant monitoring based on the targeted manufacturing of novel COFs with specific functions.

关键词： Covalent organic frameworks Thiazole Sulfur coordination Au nanoparticles Hg^(2+)-activated peroxidase-like activity

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Joint Transmit and Reflective Beamforming Design for Active IRS-Aided SWIPT Systems

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Chinese Journal of Electronics 2024年第2期33卷 536-548页

作者： Weiping SHI Qingqing wu Di wu feng SHU Jiangzhou WANG School of Electronic and Optical Engineering Nanjing University of Science and Technology Department of Electronic Engineering Shanghai Jiao Tong University School of Information and Communication Engineering Hainan University Department of Automation Shanghai Jiao Tong University School of Engineering University of Kent

To further improve the performance of passive intelligent reflecting surface(IRS)-assisted communication systems and mitigate the serious path loss due to “double-fading ” of IRS-assisted links, an active IRS-aided simultaneous wireless information and power transfer(SWIPT) system is investigated. This paper jointly optimizes the transmit beamforming at the base station(BS) and the phase shifts at the active IRS in order to maximize the power collected by the energy harvesting receiver under both perfect and imperfect channel state information(CSI)states, subject to the signal-to-interference-noise ratio constraint of the information decoding receiver, and the power constraints of the BS/IRS. Under perfect CSI, the alternating optimization algorithm is utilized for obtaining the transmit beamforming at the BS and the phase shifts at the active IRS. For each subproblem, we first transform nonconvex objective function and constraints into convex ones by performing a first-order Taylor expansion. Then, each subproblem is solved by using the interior point method. Given that obtaining perfect CSI is impractical, two robust beamforming designs are proposed for imperfect CSI case. Under the bounded CSI error model, we first transform the non-convex optimization problem into two semidefinite programming subproblems, and then solve each subproblem based on S-procedure and sequential rank-one constraint relaxation(SROCR) techniques. Under the stochastic CSI error model, the alternating optimization method is applied in an iterative manner based on Bernstein-type inequality and SROCR technique. Simulation results show that both robust and non-robust schemes for active IRS-assisted SWIPT systems can achieve extremely superior performance over conventional passive IRS-assisted systems under the same overall power budget.

关键词： Wireless communication Semidefinite programming Array signal processing Simulation Stochastic processes Transforms Receivers

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Repositioning fertilizer manufacturing subsidies for improving food security and reducing greenhouse gas emissions in China

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Journal of Integrative Agriculture 2024年第2期23卷 430-443页

作者： Zongyi wu Xiaolong feng Yumei Zhang Shenggen Fan Academy of Global Food Economics and Policy China Agricultural UniversityBeijing 100083China College of Economics and Management China Agricultural UniversityBeijing 100083China

China removed fertilizer manufacturing subsidies from 2015 to 2018 to bolster market-oriented reforms and foster environmentally sustainable ***,the impact of this policy reform on food security and the environment remains inadequately ***,although green and low-carbon technologies offer environmental advantages,their widespread adoption is hindered by prohibitively high *** study analyzes the impact of removing fertilizer manufacturing subsidies and explores the potential feasibility of redirecting fertilizer manufacturing subsidies to invest in the diffusion of these *** the China Agricultural University Agri-food Systems model,we analyzed the potential for achieving mutually beneficial outcomes regarding food security and environmental *** findings indicate that removing fertilizer manufacturing subsidies has reduced greenhouse gas(GHG)emissions from agricultural activities by 3.88 million metric tons,with minimal impact on food *** fertilizer manufacturing subsidies to invest in green and low-carbon technologies,including slow and controlled-release fertilizer,organic-inorganic compound fertilizers,and machine deep placement of fertilizer,emerges as a strategy to concurrently curtail GHG emissions,ensure food security,and secure robust economic ***,we propose a comprehensive set of government interventions,including subsidies,field guidance,and improved extension systems,to promote the widespread adoption of these technologies.

关键词： food security fertilizer manufacturing subsidies agri-food systems greenhouse gas emissions

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Do nocturnal birds use acoustic and visual cues to avoid predation by bats?

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Integrative Zoology 2024年第3期19卷 524-537页

作者： Lixin GONG Huan wu Zhiqiang WANG Hui wu Jiang feng Tinglei JIANG Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal UniversityChangchunChina Key Laboratory of Vegetation Ecology of Education Ministry Institute of Grassland ScienceNortheast Normal UniversityChangchunChina College of Life Science Jilin Agricultural UniversityChangchunChina

Anti-predation strategies are critical to animal survival and are fundamental to deciphering predator–prey *** an important defense strategy,sensory predator detection(such as through acoustic and visual cues)enables animals to assess predation risk and execute predator-avoidance behavior;however,there are limited studies on the anti-predation behavior of nocturnal *** prey of bats provides an excellent representative system for examining the anti-predation behavior of nocturnal ***,we broadcasted different types of echolocation calls of the bird-eating bat Ia io to two wild passerine birds,namely,Zosterops japonicus and Sinosuthora webbiana,that are preyed upon by ***,and presented the birds with individual bats under different light *** results showed that both bird species were able to perceive the low-frequency audible portion of the bats’echolocation calls;however,they did not exhibit escape responses to the acoustic *** the dark and under moonlit conditions,both bird species were unable to respond to active bats at close range and the birds only exhibited evasive flight behavior when bats approached or touched *** results suggest that nocturnal passerine birds may not be able to use acoustic or visual cues to detect bats and adopt evasive maneuvers to avoid *** work suggests that bat predation pressure may not elicit primary predator-avoidance responses in nocturnal passerine *** results provide new insights into the anti-predation behavior of nocturnal animals.

关键词： anti-predation behavior nocturnal animals sensory cues sensory defenses

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Significant effect of ordered micro-domain on cell boundary phase distribution and demagnetization curve squareness of Sm_(2)Co_(17)-type magnet

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Rare Metals 2024年第4期43卷 1724-1735页

作者： Zhuang Liu Hai-Chen wu chao-Yue Zhang chao-Qun Zhu Guo-Xin Chen Huan-Ming Lu Ren-Jie Chen Aru Yan CISRI&NIMTE Joint Innovation Center for Rare Earth Permanent Magnets Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201China University of Chinese Academy of Sciences Beijing100049China Analytical Center Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201China

Cu-rich cell boundary phase is difficult to precipitate evenly,resulting in a generally poor demagnetization curve squareness for Fe-rich Sm_(2)Co_(17)-type magnet,which is a key factor limiting the further improvement of magnetic energy *** this study,we report that nanoscale strip-like ordered micro-domains distributed in1:7H disordered matrix phase of the solid solution precursor is a new factor significantly affecting the precipitation and distribution of the cell boundary *** strip-like and continuous micro-twin structure with twin boundaries neatly perpendicular to the C-axis is observed after sintering *** solution treatment,sequential and long strip-like micro-twins gradually transform into disordered state along the basal plane,forming narrow disordered 1:7H(TbCu_(7)-type structure)phase between the separated strip-like ordered *** disordering transformation takes place via broken down of the long strip-like ordered micro-domains,which is accomplished by narrowing along the width direction followed by reduction of the ***,a new model revealing the effect of the ordered micro-domains on the formation of the cell boundary phase is *** boundaries enriched in Cu have already existed in the precursor with long strip-like ordered ***,the Cu-rich cell boundary phase acting as strong pinning centers cannot be precipitated homogeneously and distributed continuously after aging,resulting in a poor demagnetization curve squareness of Sm_(2)Co_(17)-type *** results indicate that significant broken down of the nanoscale ordered micro-domains in solution precursor is the key factor improving the distribution of cell boundary phase in Sm_(2)Co_(17)-type magnets.

关键词： Sm_(2)Co_(17) magnets Solution precursor Ordered micro-domains Disordering transformation Cellular structure

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Highly Aligned Graphene Aerogels for Multifunctional Composites

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Nano-Micro Letters 2024年第6期16卷 276-342页

作者： Ying wu chao An Yaru Guo Yangyang Zong Naisheng Jiang Qingbin Zheng Zhong‑Zhen Yu Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004People’s Republic of China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhenGuangdong 518172People’s Republic of China State Key Laboratory of Organic‑Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal *** maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been *** unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse *** review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their *** highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and *** oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular *** review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy *** and potential opportunities are proposed to offer new insights into prospects of this material.

关键词： Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications

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One-Pot Stereoselective Synthesis of Different Fused Multicyclic Iminosugars Based on the Iminium-lon Intermediate

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Chinese Journal of Chemistry 2024年第2期42卷 142-150页

作者： Song Xie Jilai wu Likai Zhou chao Wei Xiaoliu Li Hua Chen Key Laboratoryof Chemical Biology of Hebei Province College of Chemistry and Material ScienceHebei UniversityBaodingHebei 071002China College of Chemistry and Chemical Engineering Xingtai UniversityXingtaiHebei 054001China

Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different *** iminium-ion is the key intermediate for the *** a result,several complex fused iminosugars 3a were obtained by aza-Diels-Alder mechanism at 60℃,while a series of aza-C-glycosides 5a were prepared by Mannich reaction at room temperature accompanied by another tetrahydroquinoline-fused iminosugars 4a(tricyclic derivatives)through aza-Diels-Alder *** strategy will help to construct structurally diverse and bioactive iminosugar analogues.

关键词： Fused multicyclic iminosugar Aza-Diels-Alder cycloaddition Mannich reaction Tetrahydroquinoline Multicomponent reactions Enantioselectivity Cyclization

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Warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography

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Defence Technology（防务技术） 2024年第7期37卷 162-172页

作者： Pengyu Hu Jiangpeng wu Zhengang Yan Meng He chao Liang Hao Bai Xi'an Modern Control Technology Research Institute Xi'an710065China Xi'an OET Science and Technology Co. LtdXi'an710076China

High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high ***,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment *** address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo ***,background difference algorithm is utilized to extract the center and area of each fragment in the image ***,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment *** reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial ***,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.

关键词： Warhead fragment measurement High speed photography Stereo vision Multi-object tracking Spatio-temporal reconstruction

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Investigation of mechanical failure performance of a large-diameter shield tunnel segmental ring

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第5期25卷 411-428页

作者： Binyong GAO Renpeng CHEN Huaina wu Chengcheng ZHANG Meng FAN chao XIAO Research Center of Underground Space Advanced Technology Hunan UniversityChangsha 410082China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan UniversityChangsha 410082China Department of Civil Engineering Hunan UniversityChangsha 410082China China Construction No.5 Civil Engineering Co. Ltd.Changsha 410004China

The control criteria for structural deformation and the evaluation of operational safety performance for large-diameter shield tunnel segments are not yet clearly *** address this issue,a refined 3D finite element model was established to analyze the transverse deformation response of a large-diameter segmental *** analyzing the stress,deformation,and crack distribution of large-diameter segments under overload conditions,the transverse deformation of the segmental ring could be divided into four *** main reasons for the decrease in segmental ring stiffness were found to be the extensive development of cracks and the complete formation of four plastic *** deformation control value for the large-diameter shield tunnel segment is chosen as 8%o of the segment's outer diameter,representing the transverse deformation during the formation of the first semi-plastic hinge(i.e.,the first yield point)in the *** control value can serve as a reinforcement standard for preventing the failure of large-diameter shield tunnel *** flexural bearing capacity characteristic curve of segments was used to evaluate the structural strength of a large-diameter segmental *** was discovered that the maximum internal force combination of the segment did not exceed the segment ultimate bearing capacity curve(SUBC).However,the combination of internal force at 9°,85°,and 161°of the joints,and their symmetrical locations about the 0°-180°axis exceeded the joint ultimate bearing capacity curve(JUBC).The results indicate that the failure of the large-diameter segment lining was mainly due to insufficient joint strength,leading to an instability *** findings from this study can be used to develop more effective maintenance strategies for large-diameter shield tunnel segments to ensure their long-term performance.

关键词： Finite element model Transverse deformation response Upper overload Plastic hinges Flexural bearing capacity

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