检索结果-南通市图书馆

Gradient microstructure and superior strength-ductility synergy of AZ61 magnesium alloy bars processed by radial forging with different deformation temperatures

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第3期170卷 65-77页

作者： Jingfeng Zou Lifeng Ma Yanchun zhu Ling Qin yuan yuan School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Heavy Machinery Engineering Research Center of the Ministry Education Taiyuan University of Science and TechnologyTaiyuan 030024China Department of Engineering University of HullCottingham RdHull HU67RXUK National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering materials.In this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem peratures.The results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron grains.Different deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal slip.The deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance ability.Analysis in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem peratures.By summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.

关键词： Gradient microstructure Radial forging Strength-ductility synergy Magnesium alloy Strengthening mechanism

Micro-flow structure at regime transition from bubbling to turbulent fluidization in a fluidized bed

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 117-130页

作者： Chaoyu Yan Yue yuan Xiaoyang Wei Jesse zhu State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of Process Fluid Filtration and SeparationCollege of Mechanical and Transportation EngineeringChina University of PetroleumBeijing 102249China China Beacons Institute The University of NottinghamNingbo315100China Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioN6A 5B9Canada

Gas-solid fluidized beds have found extensive utilization in frontline manufacturing,in particular as low-velocity beds.The fluidization status,the bubbling or turbulent flow regime and the transition in between,determine the system performance in practical applications.Though the convoluted hydrodynamics are quantitively evaluated through numerous data-processing methodologies,none of them alone can reflect all the critical information to identify the transition from the bubbling to the turbulent regime.Accordingly,this study was to exploit a coupling data processing methodology,in the combination of standard deviation,power spectrum density,probability density function,wavelet transform,and wavelet multiresolution method,to jointly explain the micro-flow structure at the regime transition from bubbling to turbulent fluidization.The transient differential pressure fluctuation was measured for the evaluation in a fluidized bed(0.267 m i.d.×2.5 m height)with FCC catalysts(d_(p)=65μm,ρ_(p)=1780kg/m^(3))at different superficial gas velocities(0.02–1.4 m/s).The results show that the onset of turbulent fluidization starts earlier in the top section of the bed than in the bottom section.The wavelet decomposition displays that the fluctuation of differential pressure mainly concentrates on the sub-signals with an intermediate frequency band.These sub-signals could be synthesized into three types of scales(micro-scale,meso-scale,and macro-scale),representing the multi-scale hydrodynamics in the fluidized bed.The micro-scale signal has the characteristic information of bubbling fluidization,and the characteristic information of turbulent fluidization is mainly represented by the meso-scale signal.This work provides a systematic comprehension of fluidization status assessment and serves as an impetus for more coupling analysis in this sector.

关键词： Flow regime transition Bubbling fluidization Turbulent fluidization Micro-flow structure Differential pressure fluctuation

Granular Ionogel Particle Inks for 3D Printed Tough and Stretchable Ionotronics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2024年第1期2023卷 429-442页

作者： yuan Yao Yue Hui Zhenhua Wang Hehao Chen Heng zhu Nanjia Zhou Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake UniversityHangzhou 310024Zhejiang ProvinceChina Institute of Advanced Technology Westlake Institute for Advanced StudyHangzhou 310024Zhejiang ProvinceChina School of Chemical Engineering and Advanced Materials the University of AdelaideAdelaide 5005South AustraliaAustralia State Key Laboratory of Fluid Power&Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceCenter for X-MechanicsDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

Ionogels have garnered great attention as promising soft conducting materials for the fabrication of flexible energy storage devices,soft actuators,and ionotronics.However,the leakage of the ionic liquids,weak mechanical strength,and poor manufacturability have greatly limited their reliability and applications.Here,we propose a new ionogel synthesis strategy by utilizing granular zwitterionic microparticles to stabilize ionic liquids.The ionic liquids swell the microparticles and physically crosslink microparticles via either electronic interaction or hydrogen bonding.Further introducing a photocurable acrylic monomer enables the fabrication of double-network(DN)ionogels with high stretchability(>600%)and ultrahigh toughness(fracture energy>10 kJ/m^(2)).The synthesized ionogels exhibit a wide working temperature of−60 to 90℃.By tuning the crosslinking density of microparticles and physical crosslinking strength of ionogels,we synthesize DN ionogel inks and print them into three-dimensional(3D)motifs.Several ionogelbased ionotronics are 3D printed as demonstrations,including strain gauges,humidity sensors,and ionic skins made of capacitive touch sensor arrays.Via covalently linking ionogels with silicone elastomers,we integrate the ionogel sensors onto pneumatic soft actuators and demonstrate their capacities in sensing large deformation.As our last demonstration,multimaterial direct ink writing is harnessed to fabricate highly stretchable and durable alternating-current electroluminescent devices with arbitrary structures.Our printable granular ionogel ink represents a versatile platform for the future manufacturing of ionotronics.

关键词： crosslinking utilizing gauge

Finite-Time Stabilization for Constrained Discrete-time Systems by Using Model Predictive Control

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1656-1666页

作者： Bing zhu Xiaozhuoer yuan Li Dai Zhiwen Qiang IEEE the Seventh Research Division Beihang UniversityBeijing 100191China the School of Automation Beijing Institute of TechnologyBeijing 100081China

In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guarantees the finite-time convergence property by assigning the control horizon equal to the dimension of the overall system, and only penalizing the terminal cost in the optimization, where the stage costs are not penalized explicitly. A terminal inequality constraint is added to guarantee the feasibility and stability of the closed-loop system.Initial feasibility can be improved via augmentation. The finite-time convergence of the proposed MPC is proved theoretically,and is supported by simulation examples.

关键词： Constraints deadbeat control finite-time stabilization model predictive control(MPC)

Formation of the Tibetan Plateau during the India-Eurasia Convergence:Insight from 3-D Multi-Terrane Thermomechanical Modeling

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年第1期35卷 112-130页

作者： Jile Chen Peimin zhu Yuefeng yuan Guifan Chen School of Geophysics and Geomatics China University of GeosciencesWuhan 430074China Geothermal Engineering Research Center Three Gorges Geotechnical Consultants Co.Ltd.Wuhan 430074China

Various models exist to explain the formation of the Tibetan Plateau,including“tectonic escape”,“pure shear thickening”,“convective removal of the lithospheric mantle”,and“lower crustal flow”model.The first two models are primarily constructed on pure mechanical models but are unable to reasonably explain the tension and shear phenomena inside the plateau.The latter two are rheological dynamic models based on deep geophysical observations.However,the spatial range of the lower crustal flow and its role in the plateau formation/uplift remain controversial.Five multi-terrane viscoplastic thermomechanical models were constructed to simulate the uplift and lithospheric structure change of the Tibetan Plateau during the post-collision stage(since 35 Ma)under the convergence of the Indian Plate.Results show that the plateau's formation begins with crustal thickening,blocked by strong terranes at the northern plateau,and expanded laterally to the east.The lithosphere thickens gradually and experiences delamination at its base,elevating temperature within the crust and forming partial melting layers in the central plateau.As convergence persists on the southern side,the northern plateau's lithosphere bends downward and undergoes delamination,further heating the crust and promoting the northward and eastward flow of partial melting layers,leading to secondary uplift around the plateau.

关键词： 3-D thermomechanical modeling Tibetan Plateau plateau uplift crustal flow

Photocatalytic synthesis of small-molecule drugs by porous framework materials

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 52-65页

作者： Yingying Zhao Jiangpei yuan Lei zhu Yu Fang State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Innovation Institute of Industrial Design and Machine Intelligence Quanzhou-Hunan University Quanzhou 362801China

Small-molecule drugs are widely used in daily life.There are still issues with the current industrial synthesis techniques for small-molecule drugs,such as the use of expensive metal catalysts,convoluted reaction processes,and non-recyclable catalysts.The benefits of photocatalytic organic synthesis over conventional techniques are mild conditions,environmental friendliness,and great selectivity.Porous framework materials can precisely modulate catalytic sites'electronic state and ligand structure to improve photocatalytic performance.In particular,MOFs,COFs and PCCs based photocatalysts have received extensive research interest due to their unique morphology,structural adjustability,high photocatalytic performance,unique recyclability,excellent chemical stability,easy synthesis and low cost.Therefore,a key area for future research is the development of porous framework materials as photocatalysts for the synthesis of small-molecule drugs or drug precursors.

关键词： Small-molecule drug Porous framework materials Photocatalysis

On the Difference Between the Skew-rank of an Oriented Graph and the Rank of Its Underlying Graph

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第1期40卷 129-136页

作者： Jia-min zhu Bo-jun yuan Yi Wang School of Mathematical Sciences Anhui UniversityHefei230601China School of Science Zhejiang University of Science and TechnologyHangzhou310023China

Let G be a simple graph and G~σ be the oriented graph with G as its underlying graph and orientation σ.The rank of the adjacency matrix of G is called the rank of G and is denoted by r(G).The rank of the skew-adjacency matrix of G~σ is called the skew-rank of G~σ and is denoted by sr(G~σ).Let V(G)be the vertex set and E(G) be the edge set of G.The cyclomatic number of G,denoted by c(G),is equal to |E(G)|-|V(G)|+ω(G),where ω(G) is the number of the components of G.It is proved for any oriented graph G~σ that-2c(G)≤sr(G~σ)-r(G)≤2c(G).In this paper,we prove that there is no oriented graph G~σwith sr(G~σ)-r(G)=2c(G)-1,and in addition,there are infinitely many oriented graphs G~σ with connected underlying graphs such that c(G)=k and sr(G~σ)-r(G)=2c(G)-l for every integers k,l satisfying 0 ≤l≤4k and l≠1.

关键词： cyclomatic number rank skew-rank

Insights and implications of sexual dimorphism in osteoporosis

在线全文

学校读者我要写书评

暂无评论

Bone Research 2024年第1期12卷 20-49页

作者： yuan-yuan Zhang Na Xie Xiao-Dong Sun Edouard C.Nice Yih-Cherng Liou Canhua Huang Huili zhu Zhisen Shen Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province Sichuan Research Center for Drug Precision Industrial TechnologyWest China School of PharmacySichuan UniversityChengdu 610041China West China School of Basic Medical Sciences&Forensic Medicine Sichuan UniversityChengdu 610041China Department of Biochemistry and Molecular Biology Monash UniversityClaytonVIC 3800Australia Department of Biological Sciences Faculty of ScienceNational University of SingaporeSingapore 117543Republic of Singapore Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China Hospitaland West China School of Basic Medical Sciences&Forensic MedicineSichuan UniversityChengdu 610041China Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education Department of Reproductive MedicineWest China Second University Hospital of Sichuan UniversityChengduChina Department of Otorhinolaryngology and Head and Neck Surgery The Affiliated Lihuili HospitalNingbo University315040 NingboZhejiangChina

Osteoporosis,a metabolic bone disease characterized by low bone mineral density and deterioration of bone microarchitecture,has led to a high risk of fatal osteoporotic fractures worldwide.Accumulating evidence has revealed that sexual dimorphism is a notable feature of osteoporosis,with sex-specific differences in epidemiology and pathogenesis.Specifically,females are more susceptible than males to osteoporosis,while males are more prone to disability or death from the disease.To date,sex chromosome abnormalities and steroid hormones have been proven to contribute greatly to sexual dimorphism in osteoporosis by regulating the functions of bone cells.Understanding the sex-specific differences in osteoporosis and its related complications is essential for improving treatment strategies tailored to women and men.This literature review focuses on the mechanisms underlying sexual dimorphism in osteoporosis,mainly in a population of aging patients,chronic glucocorticoid administration,and diabetes.Moreover,we highlight the implications of sexual dimorphism for developing therapeutics and preventive strategies and screening approaches tailored to women and men.Additionally,the challenges in translating bench research to bedside treatments and future directions to overcome these obstacles will be discussed.

关键词： osteoporosis epidemiology overcome

Effects of Biostimulation-Bioaugmentation on Coastal Microbial Community in an in situ Mesocosm System

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第1期23卷 233-246页

作者： yuan Fangzheng ZHAO Yangyong DAI Yulai YANG Wen zhu Jinyong College of Marine Science Ningbo UniversityNingbo 315800China Zhejiang Easytest Environmental Technology Co. Ltd.Ningbo 315800China Hangzhou Academy of Agricultural Sciences Hangzhou 310024China

Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the response of coastal prokaryotic and eukaryotic communities to bioaugmentation and biostimulation.Here,a 28-day outdoor mesocosm experiment with two treatments(bioaugmentation-A and combined treatment of bioaugmentation and biostimulation-AS)and a control(untreated-C)were carried out.The experiment was conducted in Meishan Bay to explore the composition,dynamics,and co-occurrence patterns of prokaryotic and eukaryotic communities in response to the A and AS using 16S rRNA and 18S rRNA gene amplicon sequencing.After treatment,Gammaproteobacteria and Epsilonproteobacteria were significantly increased in group AS compared to group C,while Flavobacteriia and Saprospirae were significantly reduced.Dinoflagellata was significantly reduced in AS compared to C,while Chrysophyta was significantly reduced in both AS and A.Compared to C,the principal response curve analyses of the prokaryotic and eukaryotic communities both showed an increasing trend followed by a decreasing trend for AS.Furthermore,the trends of prokaryotic and eukaryotic communities in group A were similar to those in group AS compared with group C,but AS changed them more than A did.According to the species weight table on principal response curves,a significant increase was observed in beneficial bacteria in prokaryotic communities,such as Rhodobacterales and Oceanospirillales,along with a decrease in autotrophs in eukaryotic communities,such as Chrysophyta and Diatom.Topological properties of network analysis reveal that A and AS complicate the interactions between the prokaryotic and eukaryotic communities.Overall,these findings expand our understanding of the response pattern of the bioaugmentation and biostimulation on coastal prokaryotic and eukaryotic communities.

关键词： prokaryotic community eukaryotic community bioaugmentation biostimulation coastal waters