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Insight into vertical piezoelectric characteristics regulated thermal transport in van der Waals two-dimensional materials

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Rare Metals 2024年第2期43卷 770-779页

作者： Dong-Hai Wei E Zhou Jin-yuan Xu Hui-min Wang Chen Shen Hong-Bin Zhang Zhen-Zhen qin Guang-Zhao qin State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082China Hunan Key Laboratory for Micro-Nano Energy Materials and Device and School of Physics and Optoelectronics Xiangtan UniversityXiangtan411105China Institute of Materials Science Technical University of DarmstadtAlarich-Weiss-Str.264287DarmstadtGermany School of Physics and Microelectronics Zhengzhou UniversityZhengzhou450001China

The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.

关键词： Thermal conductivity Piezoelectric effect 2D materials Bilayer BN Strain engineering

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Pseudomonotonicity of Nonlinear Transformations on Euclidean Jordan Algebras

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 192-204页

作者： yuan-min Li School of Mathematics and Statistics Xidian UniversityXi’an710071China

In this paper, we have introduced the concepts of pseudomonotonicity properties for nonlinear transformations defined on Euclidean Jordan algebras. The implications between this property and other P-properties have been studied. More importantly, we have solved the solvability problem of the nonlinear pseudomonotone complementarity problems over symmetric cones.

关键词： Euclidean Jordan algebra nonlinear transformation complementarity problem pseudomonotone

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

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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

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Construction of Optimal Mixed-Level Uniform Designs

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Journal of Systems Science & Complexity 2024年第2期37卷 841-862页

作者： CHATTERJEE Kashinath LIU min-Qian qin Hong YANG Liuqing Department of Population Health Sciences Division of Biostatistics and Data ScienceAugusta UniversityGA 30912USA NITFID LPMC&KLMDASRSchool of Statistics and Data ScienceNankai UniversityTianjin 300071China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073China

The theory of uniform design has received increasing interest because of its wide application in the field of computer experiments.The generalized discrete discrepancy is proposed to evaluate the uniformity of the mixed-level factorial design.In this paper,the authors give a lower bound of the generalized discrete discrepancy and provide some construction methods of optimal mixed-level uniform designs which can achieve this lower bound.These methods are all deterministic construction methods which can avoid the complexity of stochastic algorithms.Both saturated mixed-level uniform designs and supersaturated mixed-level uniform designs can be obtained with these methods.Moreover,the resulting designs are also χ^(2)-optimal and minimum moment aberration designs.

关键词： Generalized discrete discrepancy Hadamard matrix mixed-level design orthogonal array supersaturated design

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A Certified Cubic B-Spline Interpolation Method with Tangential Direction Constraints

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Journal of Systems Science & Complexity 2024年第3期37卷 1271-1294页

作者： HE Shitao SHEN Liyong WU qin yuan Chunming School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China KLMM Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China

Curve interpolation with B-spline is widely used in various areas. This problem is classic and recently raised in application scenario with new requirements such as path planning following the tangential vector field under certified error in CNC machining. This paper proposes an algorithm framework to solve Hausdorff distance certified cubic B-spline interpolation problem with or without tangential direction constraints. The algorithm has two stages: The first stage is to find the initial cubic B-spine fitting curve which satisfies the Hausdorff distance constraint;the second stage is to set up and solve the optimization models with certain constraints. Especially, the sufficient conditions of the global Hausdorff distance control for any error bound are discussed, which can be expressed as a series of linear and quadratic constraints. A simple numerical algorithm to compute the Hausdorff distance between a polyline and its B-spline interpolation curve is proposed to reduce our computation.Experimental results are presented to show the advantages of the proposed algorithms.

关键词： Cubic B-spline Hausdorff distance interpolation tangential direction

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Microstructure and mechanical properties of Ti/Al/Ti clad plates prepared via powder-in-tube method

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Journal of Iron and Steel Research(International) 2024年第3期31卷 670-687页

作者： Xian-lei Hu qin-cheng Xie Yi yuan Ying Zhi State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina Suzhou Dongbao Haixing Metal Material Technology Co. Ltd.Suzhou 215600JiangsuChina School of Material Science and Engineering Northeastern UniversityShenyang 110819LiaoningChina

The Ti/Al/Ti clad plates exhibit a broad spectrum of potential applications.However,the conventional techniques of hot-pressing composite and explosive composite are intricate and environmentally hazardous.A novel method was introduced for preparing clad plates,namely,the powder-in-tube method.This method involves a combination of cold rolling,annealing at a temperature of 550℃,and double rolling.The morphology of the intermetallic compound layer was analyzed through the utilization of interface stripping test,tensile test,and microscopic characterization.The interface morphology,interface bonding properties,tensile fracture structures,and properties of plates under the first and second rolling were compared,along with the effects of intermetallic compounds on the interface properties.The results indicate that the powder-in-tube method,when annealed at 550℃,can produce a composite plate featuring a complete and uniform Ti/Al interface.The obtained plate exhibits a peeling strength of 21.5 N/mm,tensile strength of 424 MPa,and elongation of 11.5%.Furthermore,a systematic analysis was conducted to determine the causes of performance degra-dation observed during annealing at temperatures of 600 and 650℃.

关键词： Powder-in-tube method-Ti/Al/Ti clad plate Annealing Cold rolling-Mechanical property

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Manipulating fast Li_(2)S redox via carbon confinement and oxygen defect engineering of In_(2)O_(3)for lithium-sulfur batteries

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Nano Research 2024年第6期17卷 5179-5187页

作者： Jinlei qin Rui Wang Zilong yuan Pei Xiao Deli Wang Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Lithium-sulfur(Li-S)batteries have been considered as promising energy storage systems due to the merits of high energy density and low cost.However,the lithium polysulfides(LiPSs)diffusion and sluggish redox kinetics hamper the battery performance.In this work,low-bandgap indium oxide(In_(2)O_(3))with dense oxygen vacancies(In_(2)O_(3−x),0

关键词： Li-S batteries nitrogen-doped carbon confinement oxygen vacancies bidirectional Li_(2)S redox

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Human immunodeficiency virus-associated dementia complex with positive 14-3-3 protein in cerebrospinal fluid:A case report

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World Journal of Clinical Cases 2024年第12期12卷 2065-2073页

作者： Yun-Sen He Xiao-Hong qin min Feng qin-Jiang Huang Meng-Jun Zhang Li-Li Guo ming-Bin Bao Ye Tao Hong-yuan Dai Bo Wu Department of Neurosurgery Sichuan Lansheng Brain Hospital&Shanghai Lansheng Brain Hospital Investment Co.Ltd.Chengdu 610036Sichuan ProvinceChina Department of Psychiatry Sichuan Provincial Center for Mental HealthChengdu 610072Sichuan ProvinceChina Department of Geriatrics Municipal People’s Hospital in LuzhouLuzhou 646000Sichuan ProvinceChina Department of Neurosurgery Wenjiang District People’s Hospital of ChengduChengdu 611100Sichuan ProvinceChina Department of Neurosurgery Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of China ChengduChengdu 610072Sichuan ProvinceChina Department of Neurology Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072Sichuan ProvinceChina

BACKGROUND Human immunodeficiency virus(HIV)-associated dementia(HAD)is a subcortical form of dementia characterized by memory deficits and psychomotor slowing.However,HAD often presents with symptoms similar to those of Creutzfeldt-Jakob disease(CJD),particularly in patients with acquired immune deficiency syndrome(AIDS).CASE SUMMARY We report the case of a 54-year-old male who exhibited cognitive dysfunction and secondary behavioral changes following HIV infection and suspected prion exposure.The patient was diagnosed with HIV during hospitalization and his cerebrospinal fluid tested positive for 14-3-3 proteins.His electroencephalogram showed a borderline-abnormal periodic triphasic wave pattern.Contrast-enhanced magnetic resonance imaging revealed moderate encephalatrophy and demyelination.Initially,symptomatic treatment and administration of amantadine were pursued for presumed CJD,but the patient’s condition continued to deteriorate.By contrast,the patient’s condition improved following anti-HIV therapy.This individual is also the only patient with this prognosis to have survived over 4 years.Thus,the diagnosis was revised to HAD.CONCLUSION In the diagnostic process of rapidly progressive dementia,it is crucial to rule out as many potential causes as possible and to consider an autopsy to diminish diagnostic uncertainty.The 14-3-3 protein should not be regarded as the definitive marker for CJD.Comprehensive laboratory screening for infectious diseases is essential to enhance diagnostic precision,especially in AIDS patients with potential CJD.Ultimately,a trial of diagnostic treatment may be considered when additional testing is not feasible.

关键词： HIV-associated dementia Cognitive dysfunction Creutzfeld-Jakob disease Rapidly progressive dementia Case report

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Numerical analysis of the correlation between fluid dynamic modes and hydrodynamic noise in flows around a three-dimensional circular cylinder

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Journal of Hydrodynamics 2024年第1期36卷 119-129页

作者： Jia-jia qin ming-xin Zou yuan Zhuang De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China

The flow around a circular cylinder for Re=1000 is characterized by flow separation and Karman vortex street.The typical flow features can be captured to study the correlation between fluid fields and sound fields.In this paper,the three-dimensional circular cylinder is taken as the research object,and the probes of surface fluctuating pressure and far field sound pressure are arranged every 10°.The directional diagram and the coherence of fluctuating pressure and sound pressure are analyzed.The relationship between the flow mode and hydrodynamic noise is studied by using dynamic mode decomposition(DMD).The characteristics of the dipole and quadrupole sound source term of a long span cylinder are studied.The results show that at the angles between 30°–120°and 190°–350°,the fluctuating pressure contributes more to the generation of dipole sounds.The quadrupole sound source shows three-dimensional effects,which is more obvious in a cylinder with large spanwise length.

关键词： Pressure coherence dynamic mode decomposition flow-sound correlation circular cylinder

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

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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

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