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Toughening additive manufactured Zr-based bulk metallic glass composites by martensite phase transformation

Journal of Materials Science & Technology 2024年第3期170卷 95-102页

作者： Pengcheng Zhang Cheng Zhang Jie pan Di Ouyang Lin Liu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and ***,the BMGs prepared by LPBF usually suffered from less plasticity and poorer fracture toughness as compared to their cast counterparts due to partial crystallization in heat-affected zones(HAZs).Since crystallization in HAZs is hard to avoid completely in LPBF BMGs,it is desirable to design a suitable alloy system,in which only ductile crystalline phase,instead of brittle intermetallics,is formed in *** unique structure could effectively increase the toughness/plasticity of the LPBF *** achieve this goal,a quaternary BMG system with a composition of Zr_(47.5)Cu_(45.5)Al_(5)Co_(2)is adopted and subjected to *** is found that nearly a single phase of B_(2)-ZrCu is precipitated in HAZs,while a fully amorphous phase is formed in molten pools(MPs).This B_(2)phase reinforced BMG composite exhibits excellent mechanical properties with enhanced plasticity and ***,it is easy to modulate the mechanical properties by altering the amount of the B_(2)phase via adjusting the laser energy ***,the best combination of strength,plasticity,and notch toughness is obtained in the BMG composite containing 27.4%B_(2)phase and 72.6%amorphous phase,which exhibits yield strength(σ_(s))of 1423 MPa,plastic strain(ε_(p))of 4.65%,and notch toughness(K_(q))of 53.9 MPa m 1/***,a notable strain-hardening is also *** improvement of plasticity/toughness and appearance of strain-hardening behavior are mainly due to the martensite phase transformation from the B_(2)phase to the Cm phase during plastic deformation(i.e.,the phase transformation-induced plasticity effect).The current work provides a guide for making advanced BMGs and BMG composites by additive manufacturing.

关键词： Laser powder bed fusion Bulk metallic glass composites Phase transformation-induced plasticity Deformation mechanism

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Link between childhood obesity and gut microbiota

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World Journal of Gastroenterology 2024年第30期30卷 3560-3563页

作者： Yan pan Fu-Yong Jiao Department of Pediatrics The First Affiliated Hospital of Yangtze UniversityJingzho 434000Hubei ProvinceChina shaanxi Kawasaki Disease Diagnosis and Treatment Center Children's HospitalShaanxi Provincial People's Hospital of Xi'anJiaotong UniversityXi'an 710000Shaanxi ProvinceChina

Childhood obesity is a critical global health concern with rising prevalence and significant long-term health *** studies have implicated gut microbiota in the development and progression of *** editorial analyzes the research conducted by Li et al,who utilized 16S rRNA gene sequencing to compare the gut microbiome of overweight and healthy-weight *** study found significant differences in microbial diversity and composition between the two groups,with potential implications for understanding and managing childhood *** analyzed the study’s advantages and drawbacks,proposing potential areas for future research to better understand the connection between gut microbiota and obesity.

关键词： 16S rRNA Childhood obesity Gut microbiota Future research Global health

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Effect of NaCl Concentration on the Cumulative Strain and Pore Distribution of Clay under Cyclic Loading

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Fluid Dynamics & Materials Processing 2024年第2期20卷 447-461页

作者： Xinshan Zhuang shunlei Xia Ruijie pan School of Civil Engineering and Architecture Hubei University of TechnologyWuhan430068China

Clay,as the most common soil used for foundationﬁll,is widely used in various infrastructure *** phy-sical and mechanical properties of clay are inﬂuenced by the pore solution *** study uses a GDS static/dynamic triaxial apparatus and nuclear magnetic resonance experiments to investigate the effects of cyclic loading on clay ***,the development of cumulative strain in clay is analyzed,and aﬁtting model for cumulative plastic strain is introduced by considering factors such as NaCl solution concentration,con-solidation stress ratio,and cycle *** particular,the effects of the NaCl solution concentration and con-solidation stress ratio on the pore distribution of the test samples before and after cyclic loading are examined,and the relationship between microscopic pore size and macroscopic cumulative strain is obtained *** results show that as the consolidation stress ratio grows,an increasing number of large pores in the soil samples are transformed into small *** the NaCl solution concentration becomes higher,the number of small pores gradually decreases,while the number of large pores remains *** loading causes the disappearance of the large pores in the samples,and the average pore size before cyclic loading is posi-tively correlated with the axial cumulative strain after cyclic *** cumulative strain produced by the soil under cyclic loading is inversely proportional to the NaCl solution concentration and consolidation stress ratio.

关键词： Geotechnical engineering clay cyclic loading nuclear magnetic resonance NaCl solution consolidation ratio accumulative strain

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Deep reinforcement learning for online scheduling of photovoltaic systems with battery energy storage systems

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Intelligent and Converged Networks 2024年第1期5卷 28-41页

作者： Yaze Li Jingxian Wu Yanjun pan the Department of Electrical Engineering University of ArkansasFayettevilleAR 72701USA the Department of Computer Science and Computer Engineering University of ArkansasFayettevilleAR 72701USA

A new online scheduling algorithm is proposed for photovoltaic(PV)systems with battery-assisted energy storage systems(BESS).The stochastic nature of renewable energy sources necessitates the employment of BESS to balance energy supplies and demands under uncertain weather *** proposed online scheduling algorithm aims at minimizing the overall energy cost by performing actions such as load shifting and peak shaving through carefully scheduled BESS charging/discharging *** scheduling algorithm is developed by using deep deterministic policy gradient(DDPG),a deep reinforcement learning(DRL)algorithm that can deal with continuous state and action *** of the main contributions of this work is a new DDPG reward function,which is designed based on the unique behaviors of energy *** new reward function can guide the scheduler to learn the appropriate behaviors of load shifting and peak shaving through a balanced process of exploration and *** new scheduling algorithm is tested through case studies using real world data,and the results indicate that it outperforms existing algorithms such as Deep *** online algorithm can efficiently learn the behaviors of optimum non-casual off-line algorithms.

关键词： photovoltaic(PV) battery energy storage system(BESS) Markov decision process(MDP) deep deterministic policy gradient(DDPG)

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Who is Who in the Carbene Chemistry of N-Sulfonyl Hydrazones

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Chinese Journal of Chemistry 2024年第17期42卷 2071-2108页

作者： Paramasivam Sivaguru Yongzhen pan Nan Wang Xihe Bi Departmentof Chemistry Northeast Normal UniversityChangchunJilin130024China

Over the past few decades,N-sulfonyl hydrazones have been recognized as alternative precursors for hazardous diazo compounds in organic synthesis,allowing for diverse innovative and original chemical transformations that were otherwise difficult to *** critical review summarizes the major advancements in the carbene chemistry of N-sulfonyl *** contents of this review are organized based on research conducted by leading scientists who have made significant contributions to this *** individual carbene transfer reactions and their mechanisms,as well as the potential applications in the synthesis of natural products and complex bioactive molecules,are thoroughly discussed.

关键词： N-Sulfonyl hydrazones Carbene chemistry Cross-coupling Cycloaddition Asymmetric reactions

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Friction moment calculation method for tapered roller bearings under combined loads

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Science China(Technological Sciences) 2024年第8期67卷 2565-2578页

作者： LI XinBin LIU Jing HUANG SuHe pan Guang School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory for Unmanned Underwater Vehicle Northwestern Polytechnical UniversityXi’an 710072China System Engineering Research Institute Beijing 100094China

Tapered roller bearings(TRBs) can withstand axial loads, radial loads, and overturning moments. The performance, safety, and efficiency of rotating machinery are directly influenced by the friction moments within the TRBs. However, most current research has relied on empirical formulas that focus on axial loads. Additionally, the friction coefficient between the rollers and the inner ring rib has been defined using simple empirical methods. In actual applications, the loads on TRBs are not purely axial or radial, and simple empirical friction coefficients do not adequately account for the varying lubrication conditions. To address this challenge, this study proposes an improved method for calculating the friction moments of TRB under combined axial and radial loads. This study employs a calculation method for sliding friction coefficients that can model dry, boundary, elastohydrodynamic, and mixed lubrication conditions. To demonstrate the advantages of the proposed method, the friction moments obtained using the existing and proposed methods are compared. Additionally, the influence of TRB structural parameters on the friction moment is discussed. An experimental study is conducted to validate the effectiveness of the proposed method. The findings provide valuable insights for designing TRB structural parameters to minimize friction moments.

关键词： tapered roller bearing friction moment structural parameters combined loads

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Wavelet Multi-Resolution Interpolation Galerkin Method for Linear Singularly Perturbed Boundary Value Problems

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 297-318页

作者： Jiaqun Wang Guanxu pan Youhe Zhou Xiaojing Liu School of Management Science and Engineering Anhui University of Finance and EconomicsBengbu233030China Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou730000China

In this study,a wavelet multi-resolution interpolation Galerkin method(WMIGM)is proposed to solve linear singularly perturbed boundary value *** conventional wavelet schemes,the proposed algorithm can be readily extended to special node generation techniques,such as the shishkin *** a wavelet method allows a high degree of local refinement of the nodal distribution to efficiently capture localized steep *** the shape functions possess the Kronecker delta property,making the imposition of boundary conditions as easy as that in the finite element *** numerical examples are studied to demonstrate the validity and accuracy of the proposedwavelet *** results showthat the use ofmodified shishkin nodes can significantly reduce numerical oscillation near the boundary *** with many other methods,the proposed method possesses satisfactory accuracy and *** theoretical and numerical results demonstrate that the order of theε-uniform convergence of this wavelet method can reach 5.

关键词： Wavelet multi-resolution interpolation Galerkin singularly perturbed boundary value problems mesh-free method shishkin node boundary layer

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The rate dependence of the dielectric strength of dielectric elastomers

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International Journal of Smart and Nano Materials 2024年第1期15卷 110-126页

作者： Xianghe Zheng Jianyou Zhou pan Jia Zheng Zhong School of Science Harbin Institute of TechnologyShenzhenChina

Elastomers are widely used in electronics and electrical devices,either as insulators or *** insulation and actuation performance of elastomers are highly suscepti-ble to their dielectric *** the factors that influ-encethedielectricstrength ofelastomers,material viscoelasticity is an important factor that needs further *** the material viscoelasticity is often character-ized by rate-dependent behaviors,we present two different sample configurations to experimentally examine the electrical and mechanical rate dependence of the dielectric strength of VHB 4905 *** pre-stretch ratio of 4,the improve-ment of the dielectric strength is about 30%from voltage ramp of 50 V/s to 800 V/***,with an in-house biaxial test platform,the effect of the stretching rate on the dielectric strength is examined for the first *** improvement of the dielectric strength is about 35%from stretching rate of 0.1 mm/s to 5 mm/***,a dielectric strength predictor based on configurational stress is adopted to describe the experimental *** to the predictor,the loading rate affects the dielectric strength of the elastomer mainly by influencing the evolution of the inelastic deformation.

关键词： Dielectric strength dielectric elastomers material viscoelasticity rate-dependence configurational stress

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Frustrated superconductivity and sextetting order

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 168-176页

作者： Zhiming pan Chen Lu Fan Yang Congjun Wu Institute for Theoretical Sciences Westlake UniversityHangzhou 310024China New Cornerstone Science Laboratory Department of PhysicsSchool of ScienceWestlake UniversityHangzhou 310024China School of Physics Beijing Institute of TechnologyBeijing 100081China Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China

The superconducting state typically favors a uniform spatial distribution akin to ***,the pair-densitywave state exhibits sign changes in the pairing order,leading to potential frustrations in phase *** propose a mechanism to the sextetting order stemming from the frustrations in the phase coherence of a pair-density-wave state,whose spatial modulation manifests a vortex-antivortex honeycomb *** classical ground state configurations are mapped to Baxter's three-coloring model,revealing a macroscopic degeneracy accompanied by extensive *** phase coherence problem intertwines the U(1)phases and the vorticity *** the resultant color and phase fluctuations suppress the pair-densitywave order,they maintain the sextetting order above the superconducting transition temperature(T_(c)).The 1/3-fractional vortex emerges as the fundamental topological defect in the sextetting *** novel mechanism of frustrated superconductivity provides an alternative explanation for the experimental observed fractional oscillations in CsV_(3)Sb_(5).

关键词： frustrated superconductivity pair density wave charge-6e order

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A Novel Fall Detection Framework Using Skip-DSCGAN Based on Inertial Sensor Data

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Computers, Materials & Continua 2024年第1期78卷 493-514页

作者： Kun Fang Julong pan Lingyi Li Ruihan Xiang College of Information Engineering China Jiliang UniversityHangzhou310018China

With the widespread use of Internet of Things(IoT)technology in daily life and the considerable safety risks of falls for elderly individuals,research on IoT-based fall detection systems has gainedmuch *** paper proposes an IoT-based spatiotemporal data processing framework based on a depthwise separable convolution generative adversarial network using skip-connection(Skip-DSCGAN)for fall *** method uses spatiotemporal data from accelerometers and gyroscopes in inertial sensors as input data.A semisupervised learning approach is adopted to train the model using only activities of daily living(ADL)data,which can avoid data imbalance ***,a quantile-based approach is employed to determine the fall threshold,which makes the fall detection frameworkmore *** proposed fall detection framework is evaluated against four other generative adversarial network(GAN)models with superior anomaly detection performance using two fall public datasets(SisFall&MobiAct).The test results show that the proposed method achieves better results,reaching 96.93% and 92.75% accuracy on the above two test datasets,*** the same time,the proposed method also achieves satisfactory results in terms ofmodel size and inference delay time,making it suitable for deployment on wearable devices with limited *** addition,this paper also compares GAN-based semisupervised learning methods with supervised learning methods commonly used in fall *** clarifies the advantages of GAN-based semisupervised learning methods in fall detection.

关键词： Fall detection skip-connection depthwise separable convolution generative adversarial networks inertial sensor

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