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Effect of Mn content on microstructure and properties of AlCrCuFeMnx high-entropy alloy

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China Foundry 2024年第2期21卷 147-158页

作者： Ning Wang Kai Ma Qiu-da Li Yu-dong Yuan Yan-chun Zhao Li Feng School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Reuse of Nonferrous Metals Lanzhou 730050China CNNC Nuclear Power operation and Management Co. Ltd.Haiyan 314300ZhejiangChina

AlCrCuFeMnx(x=0,0.5,1,1.5,and 2)high-entropy alloys were prepared using the vacuum arc melting *** microstructure and mechanical properties of AlCrCuFeMnxwere analyzed and tested by XRD,SEM,TEM,nanoindentation,and electronic universal *** results indicate that the AlCrCuFeMnxhigh-entropy alloy exhibits a dendritic structure,consisting of dendrites with a BCC structure,interdendrite regions with an FCC structure,and precipitates with an ordered BCC structure that form within the ***(Mn)has a strong affinity for dendritic,interdendritic,and precipitate structures,allowing it to easily enter these *** an increase in Mn content,the size of the precipitated nanoparticles in the dendritic region initially increases and then ***,the area fraction initially decreases and then ***,the alloy’s strength and wear resistance decrease,while its plasticity *** Al Cr Cu Fe Mn1.5alloy boasts excellent mechanical properties,including a hardness of 360 HV and a wear rate of 2.4×10^(-5)mm^(3)·N^(-1)·mm^(-1).It also exhibits impressive yield strength,compressive strength,and deformation rates of 960 MPa,1,700 MPa,and 27.5%,respectively.

关键词： high-entropy alloys microstructure mechanical properties wear resistance strengthening mechanisms

Dynamical switchable quantum nonreciprocity induced by off-resonant chiral two-photon driving

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 31-37页

作者： da-Wei Liu Zi-Hao Li Shi-Lei Chao Ying Wu Liu-Gang Si School of Physics and Institute for Quantum Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

optical nonreciprocity,which refers to the direction-dependent emission,scattering and absorption of photons,plays a very important role in quantum engineering and quantum information ***,we propose an all-optical approach to achieve the optical dynamical switchable quantum nonreciprocity by an off-resonant chiral two-photon driving in a single microring cavity,which differs from the conventional nonreciprocal *** is shown that the optical field with time-dependent statistical properties can be generated and the nonreciprocity flips periodically,with switchable photon blockade and photon-induced tunneling *** find that the dynamical system is robust and immune to the parameter variations,which loosens the parameter range of ***,the time window for one-way quantum information is sufficiently wide and *** work opens a new idea for the current quantum nonreciprocal research,which can facilitate a memory functionality and be used for future inmemory superconducting quantum *** other nonreciprocal quantum devices,i.e.,dynamical switchable nonreciprocal squeezing and entanglement,may be inspired by our method,which is expected to have important applications in future quantum technology.

关键词： dynamical switchable nonreciprocity single-photon source chiral two-photon driving

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P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures

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Petroleum Science 2024年第1期21卷 143-161页

作者： Sheng-Qing Li Wen-Hao Wang Yuan-da Su Jun-Xin Guo Xiao-Ming Tang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Laoshan National Laboratory Qingdao 266071ShangdongChina Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and TechnologyShenzhen 518055GuangdongChina Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055GuangdongChina

P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned ***,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic ***,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the *** Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and *** then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy *** results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave *** coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV *** oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV *** a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.

关键词： Aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow

Analysis and optimization of the Electrohydraulic Forming Process of Sinusoidal Corrugation Tubes

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Fluid Dynamics & Materials Processing 2024年第4期20卷 873-887页

作者： da Cai Yinlong Song Hao Jiang Guangyao Li Junjia Cui State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan UniversityChangsha410082China

Aluminum alloy thin-walled structures are widely used in the automotive industry due to their advantages related to light weight and *** can be produced at room temperature by the electrohydraulic forming *** the present study,the influence of the related parameters on the forming quality of a 6063 aluminum alloy sinusoidal corrugation tube has been *** particular,the orthogonal experimental design(oED)and central composite design(CCD)methods have been *** the range analysis and variance analysis of the experimental data,the influence degree of wire diameter(WD)and discharge energy(DE)on the forming quality was *** regression analysis was performed using the response surface methodology.A prediction model for the attaching-die state coefficient was established *** following optimal arrangement of parameters was obtained(WD=0.759 mm,DE=2.926 kJ).The attaching-die state coefficient reached the peak value of *** optimized wire diameter and discharge energy for a better attaching-die state could be screened by CCD compared with *** response surface method in CCD was more suitable for the design and optimization of the considered process parameters.

关键词： Electrohydraulic forming aluminum alloy tube process parameters attaching-die state 1 Introduction

Stability analysis of a time-delayed Van der Pol–Helmholtz–Duffing oscillator in fractal space with a non-perturbative approach

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Communications in Theoretical Physics 2024年第4期76卷 22-31页

作者： Yusry o El-Dib Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

The time-delayed fractal Van der Pol–Helmholtz–Duffing(VPHD)oscillator is the subject of this paper,which explores its mechanisms and highlights its stability *** time-delayed technologies are currently garnering significant attention,the focus of this research remains crucially relevant.A non-perturbative approach is employed to refine and set the stage for the system under *** innovative methodologies introduced yield an equivalent linear differential equation,mirroring the inherent nonlinearities of the ***,the incorporation of quadratic nonlinearity into the frequency formula represents a cutting-edge *** analytical solution's validity is corroborated using a numerical *** conditions are ascertained through the residual Galerkin ***,it is observed that the delay parameter,in the context of the fractal system,reverses its stabilizing influence,impacting both the amplitude of delayed velocity and the *** analytical solution's precision is underscored by its close alignment with numerical ***,the study reveals that fractal characteristics emulate damping *** its applicability across diverse nonlinear dynamical systems,this non-perturbative approach emerges as a promising avenue for future research.

关键词： Van der Pol-Helmholtz-Duffing oscillator fractal space time-delay non-perturbative approach stability analysis El-Dib's frequency formula

Multi-gait snake robot for inspecting inner wall of a pipeline

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Biomimetic Intelligence & Robotics 2024年第2期4卷 32-41页

作者： Jingwei Liu Man Li Yahui Wang da Zhao Rui Deng School of Electrical and Information Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Bejing Key Laboratory of Robot Bionics and Function Research Bejing 100044China

In the field of pipeline inner wall inspection,the snake robot demonstrates significant advantages over other inspection *** a simple traveling wave or meandering motion will suffice for inspecting the inner wall of small-diameter pipes,comprehensively and meticulously inspecting the inner wall of large-diameter pipes requires the snake robot to adopt a helical gait that closely adheres to the inner *** review of existing literature indicates that most research and development on the helical gait of snake robots has focused on the outer surface of cylinders,with very few studies dedicated to developing a helical gait specifically for the inspection of the inner wall of ***,in this study,we propose a helical gait that is suitable for the inner wall of pipes and meets the requirements of gas pipeline *** helical gait is designed using the backbone curve ***,we create a mathematical model for a circular helix curve with constant curvature and torsion,ensuring it is applicable to a snake robot prototype in a laboratory *** calculate the joint angles required for two conical spiral curves with variable curvature and torsion,establish a new model,and define the physical significance of the specific *** ensure the feasibility of the proposed gait,we conduct experiments involving meandering and traveling wave motions to verify the communication and control between the host computer and the snake *** upon this foundation,we further validate the mathematical model of the complex helical motion gait through simulation *** findings provide a theoretical basis for realizing helical movement with a real snake robot.

关键词： Pipeline inner wall detection Snake robot Spiral motion Backbone curve Modeling and simulation

Tinea of Vellus Hair Caused by Trichophyton violaceum in a Child:A Case Report

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International Journal of Dermatology and Venereology 2024年第1期7卷 58-59页

作者： Ge Song Guan-Zhao Liang Wei-da Liu Department of Medical Mycology Hospital for Skin Diseases(Institute of Dermatology)Chinese Academy of Medical Sciences and Peking Union Medical College&Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIsNanjingJiangsu 210042China Center for Global Health School of Public HealthNanjing Medical UniversityNanjingJiangsu 211166China

Introduction:Tinea of vellus hair is a rare dermatophytosis,caused by dermatophyte infection in the vellus *** clinical symptoms of tinea of vellus hair are more serious and the conventional topical treatment are often ***,we report a case of tinea of vellus hair caused by Trichophyton violaceum in a *** presentation:A 7-year-old boy presented with a localized,scaly,and itchy erythema on his left cheek for two *** once used a topical corticosteroid but without any clinical improvement,the erythema was progressively enlarging and spread to the left *** denied any contact with *** microscopy found abundant spores and hyphae on the vellus hair;*** was identified by culture and PCR *** patient was diagnosed with tinea of vellus hair and cured after treating with oral terbinafine 125 mg/day and topical treatment for two *** was no recurrence during the follow-up ***:The clinical symptoms of tinea of vellus hair are often atypical and easy to be *** fungal examination is necessary for suspicious patients and confirmed patients should be treated with oral antifungal ***:The diagnosis and treatment of tinea of vellus hair need to be paid more attention in clinical works.

关键词： tinea vellus hair case report

Valorization of Tree Bark-Derived Suberin in Applications for the Bio-Based Composites Industry–A Recent Review

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Journal of Renewable Materials 2024年第6期12卷 1029-1042页

作者： Aleksandra Jeżo Institute of Wood Sciences and Furniture SGGWNowoursynowska St.159Warsaw02-776Poland

Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based *** addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental *** is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic *** main role as a plant ingredient is to protect against microbiological factors and water *** of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier ***,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based *** its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer *** article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.

关键词： Suberin suberinic acids wood composites biocomposites biopolyester

Efficient privacy-preserving federated learning under dishonest-majority setting

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Science China(Information Sciences) 2024年第5期67卷 323-324页

作者： Yinbin Miao da KUANG Xinghua LI Tao LENG Ximeng LIU Jianfeng MA School of Cyber Engineering Xidian University Intelligent Policing Key Laboratory of Sichuan Province Sichuan Police College Institute of Information Engineering Chinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences Key Laboratory of Information Security of Network Systems Fuzhou University

Federated learning(FL) is an emerging distributed learning paradigm that solves the problem of isolated data by jointly learning the global model through distributed ***, recent studies have shown that FL may not always guarantee sufficient privacy preservation, this is mainly because the model parameters(e.g., weights or gradients)may leak sensitive information to malicious adversaries.

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