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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 983-1000页

作者： Xiaoyang SU tong hu Wei ZHANG Houjun KANG Yunyue CONG Quan YUAN School of Civil Engineering and Architecture Guangxi UniversityNanning 530004China Scientific Research Center of Engineering Mechanics Guangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Guangxi UniversityNanning 530004China

Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical *** study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving *** the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable ***,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are *** demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also *** this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried *** results show the accuracy and efficiency of the TMM.

关键词： transfer matrix method(TMM) free vibration forced vibration functionally graded material(FGM) stepped beam

A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1243-1260页

作者： Long zhao Zeqi LU hu DING Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China School of Microelectronics Shanghai UniversityShanghai201800China

Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant *** has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic *** paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration *** viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy *** nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction *** dynamic equations of viscoelastic metamaterials under transverse excitation are established,and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are *** results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band *** the same time,the elastic waves are limited in the nonlinear resonator with an energy harvesting function,which improves the energy ***,an experimental platform of viscoelastic metamaterial vibration is established for validation purposes.

关键词： viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting

Underwater Directional Acoustic Source Based on Pentamode Material

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Acta Mechanica Solida Sinica 2024年第1期37卷 1-9页

作者： Binghao zhao Peng Wang Dongwei Wang Gengkai hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research Institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal *** these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other ***,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted *** contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency

A novel multi-slice electromagnetic field-circuit coupling method for transient computation of long-distance gas-insulated transmission lines

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High Voltage 2024年第4期9卷 826-838页

作者： Shucan Cheng Yanpu zhao Kejia Xie Bin hu School of Electrical Engineering and Automation Wuhan UniversityWuhanChina Shandong Taikai High Voltage Switchgear Co. Ltd.TaianChina

Accurate calculation of short-circuit electromagnetic force is crucial for both mechanical strength check and the optimal design of gas-insulated transmission lines(GIL).Since the full 3D numerical simulation method is highly time-consuming,a novel lightweight 2D multi-slice electromagnetic field-circuit coupled method for computing transient electromagnetic force is proposed,where appropriate port voltage degrees of freedom(DoFs)are introduced for the solid GIL conductor *** the transient magnetic field equations are combined with the constraint equations of circuit part,including nodal voltage and loop current DoFs,a direct field-circuit coupling scheme is thus *** proposed method can simultaneously consider the effect of interphaseshunts and ground wires,as well as the skin effect and proximity *** can accurately capture the transient electromagnetic characteristics of GIL spanning from several to tens of kilometers under different short-circuit *** transient electromagnetic forces,as well as the induced voltages and currents of the enclosure,are analysed by the proposed method for both single-phase and three-phase enclosed GIL under various short-circuit *** proposed method has the advantages of high accuracy and lightweight computational cost,and thus it is also suitable for conducting important simulation tasks such as mechanical strength checks during the design optimisation phase of long-distance GIL.

关键词： transient coupling field

Surface tension of single suspended aerosol microdroplets

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Chinese Chemical Letters 2024年第4期35卷 520-524页

作者： Yukai tong Zhijun Wu Bo Zhou Min hu Anpei Ye Key Laboratory for the Physics and Chemistry of Nanodevices School of ElectronicsPeking UniversityBeijing 100871China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei, and the gas-particle partitioning. However, directly measuring the surface tension of single ambient aerosol is quite challenging, due to the limitations of their picolitre volumes and thermal motion. Here, we developed a dual laser tweezers Raman spectroscopy(DLT-RS) system to directly sense the surface tension of single airborne microdroplets(PM10particles). A pair of aerosol droplets were trapped and driven to coalesce by the laser tweezers. Meanwhile, the backscattering light intensity and brightfield images during the coalescence process were recorded to characterize the aerosol surface tension. A remarkable advantage of directly sensing aerosol surface tension is that the solutes in aerosols are often supersaturated, which is common in atmospheric aerosols but almost unavailable in bulk *** experimentally measured the surface tension of aerosols composed of nitrates or oxalic acid/nitrate mixture. Besides, the variation of surface tension during aerosol aging process was also explored, which brings possible implications on the surface evolution of actual ambient aerosol during their atmospheric lifetime.

关键词： Surface tension Droplet coalescence Single aerosol Laser tweezers Aerosol aging

Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

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Science China Earth Sciences 2024年第5期67卷 1698-1713页

作者： Bing HAN Wenbao hu Guoze zhao Ji TANG State Key Laboratory of Earthquake Dynamics Institute of GeologyBeijing 100029China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education Yangtze UniversityWuhan 430100China

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.

关键词： MT responses Identifying SEM anomaly Vector electric dipole responses Localizing SEM sources by inversion

Cytospora pyri promotes Erwinia amylovora virulence by providing metabolites and hyphae

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Journal of Integrative Agriculture 2024年第9期23卷 3045-3054页

作者： tong Shen Mengdi Ye Yeping Xu Bohan Ding Hongtao Li Li Zhang Jun Wang Yanli Tian Baishi hu Youfu zhao College of Plant Protection/Key Laboratory of Integrated Management of Crop Diseases and Pests Nanjing Agricultural UniversityNanjing 210095China Key Laboratory of Plant Quarantine Pests Monitoring and Control Ministry of Agriculture and Rural AffairsNanjing 210095China Plant Protection and Quarantine Station of Xinjiang Uygur Autonomous Region Urumqi 830001China Xinjiang Key Laboratory of Agricultural Biosafety Institute of Plant ProtectionXinjiang Academy of Agricultural SciencesUrumqi 830013China College of Agriculture Xinjiang Agricultural UniversityUrumqi 830052China Plant Pathology Department Washington State UniversityProsserWA 24106USA

Bacterial-fungal interactions are widespread in *** observed that pear orchards affected by Cytospora pyri(formerly Valsa pyri)were often accompanied with Erwinia ***,the relationship of the two pathogens was *** objective of this study was to determine whether the synergistic effect exists between *** and *** first analyzed the coexistence frequencies of *** and *** in pear *** of the two pathogens,growth,physical interactions,amylovoran production,and expression of genes for amylovoran biosynthesis were *** results showed that *** and *** could coexist on the same lesion and caused much more severe *** also found that *** could physically attach to *** and the expression of amylovoran biosynthesis genes were up-regulated with fungal metabolite *** results indicate that *** and *** can cooperatively interact,which provides *** with an opportunity to promote bacterial dispersal and production of virulence factor in ***.

关键词： pear fire blight Erwinia amylovora Valsa canker amylovoran synergy

Study on the low mechanical anisotropy of extruded Mg-Zn-Mn-Ce-Ca alloy tube in the compression process

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Journal of Magnesium and Alloys 2024年第3期12卷 1054-1067页

作者： Dandan Li Qichi Le Xiong Zhou Xiaoqiang Li Chenglu hu Ruizhen Guo tong Wang Ping Wang Wenxin hu The Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China

In this study,the extruded Mg-Zn-Mn-Ce-Ca alloy tube with a low compression anisotropy along the ED,45ED and TD was *** effect of the second phases,initial texture and deformation behavior on this low mechanical anisotropy was *** results revealed that the alloy tube contains the high content(Mg1-xZnx)11Ce phase and the low content of Mg12Ce *** second phases are respectively incoherent and coherent with the Mg matrix,and their influence can be ***,the alloy tube exhibited a weak basal fiber texture,where the c-axis was aligned along the 0°∼30°tilt from TD to *** a texture made the initial deformation(at 1.0%∼1.6%strain)of the three samples controlled by comparable basal*** deformation progressed(1.6∼9.0%strain),larger amounts of ETWs nucleated and gradually approached saturation in the three samples,re-orienting the c-axis to a 0°∼±30°deviation with respect to the loading ***,the prismatic and pyramidalslips replaced the dominant deformation progressively until ***,the similar deformation mechanisms determined by the weak initial texture in the three samples contribute to the comparable strain hardening rates,resulting in the low compressive anisotropy of the alloy tube.

关键词： Mg alloy tube Low mechanical anisotropy Weak texture Deformation mechanism.

Flexural behavior of textile reinforced mortar-autoclaved lightweight aerated concrete composite panels

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 776-787页

作者： Liying GUO Mingke DENG Wei ZHANG tong LI Yangxi ZHANG Mengyu CAO Xian hu Department of Civil Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key Lab of Structural Engineering and Earthquake Resistance Ministry of Education(XAUAT)Xi’an 710055China Scene engineering design institute Xi’an 710016China Dahua Group Shang hai 200062China

To improve the deficiencies of prefabricated autoclaved lightweight aerated concrete(ALC)panel such as susceptibility to cracking and low load-bearing capacity,a textile-reinforced mortar-autoclaved lightweight aerated concrete(TRM-ALC)composite panel was developed in this *** group of reference ALC panels and five groups of TRM-ALC panels were fabricated and subjected to four-point flexural *** was applied on the tensile side of the ALC panels to create *** variable parameters were the plies of textile(one or two),type of textile(basalt or carbon),and whether the matrix(without textile)was applied on the compression side of *** results showed that a bonding only 8-mm-thick TRM layer on the surface of the ALC panel could increase the cracking load by 180%−520%.The flexural capacity of the TRM-ALC panel increased as the number of textile layers *** reinforcement of the matrix on the compressive side could further enhance the stiffness and ultimate loadbearing capacity of the TRM-ALC *** panels with basalt textile failed in flexural mode,with the rupture of fabric *** with carbon textile failed in shear mode due to the ultra-high tensile strength of *** addition,analytical models related to the different failure modes were presented to estimate the ultimate load-carrying capacity of the TRM-ALC panels.

关键词： prefabricated autoclaved lightweight aerated concrete panel textile-reinforced mortar cracking load flexural capacity stiffness

Impact of dietary supplementation with β-alanine on the rumen microbial crude protein supply, nutrient digestibility and nitrogen retention in beef steers elucidated through sequencing the rumen bacterial community

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Animal Nutrition 2024年第2期17卷 418-427页

作者： Jinming hu Shuo Zhang Mengmeng Li Guangyong zhao State Key Laboratory of Animal Nutrition College of Animal Science and Technology China Agricultural University

This study investigated the effects of β-alanine(β-Ala) on rumen fermentation, nutrient digestibility,nitrogen(N) metabolism, plasma biochemical parameters, and rumen bacterial communities in beef steers. Six steers with initial liveweight of 252.8 ± 5.2 kg and 3 treatments of supplementing with 0, 30,or 60 g β-Ala per day to basal diet were allocated in a replicated 3 × 3 Latin square design. Each experimental period was 20 d, of which the first 15 d were for adaptation and the subsequent 5 d were for sampling. The results showed that β-Ala linearly increased the ruminal concentration of microbial crude protein(MCP)(P = 0.005), but it did not affect the ruminal concentrations of ammonia N and total volatile fatty acids(P > 0.10). β-Ala also linearly increased the dry matter(DM)(P = 0.009), organic matter(OM)(P = 0.017) and crude protein(CP)(P = 0.043) digestibility, tended to decrease the acid detergent fiber digestibility(P = 0.077), but it did not affect the neutral detergent fiber digestibility(P = 0.641). β-Ala quadratically increased the relative abundance of ruminal Bacteroidota(P = 0.021) at the phylum level, and increased Prevotella(P = 0.028) and Prevotellaceae＿UCG-003(P = 0.014), and decreased the relative abundance of NK4A214＿group(P = 0.009) at the genus level. Feeding steers with β-Ala linearly increased the urinary N(P = 0.006), urea excretions(P = 0.002) and the N retention(P = 0.004), but it did not affect the N utilization efficiency(P = 0.120). β-Ala quadratically increased the plasma concentration of the total antioxidant capacity(P = 0.011) and linearly increased the plasma concentration of insulin-like growth factor-1(P < 0.001). In summary, dietary supplementation with β-Ala improved the rumen MCP supply and increased the digestibility of DM, OM, CP and the N *** research is necessary to verify the ruminal degradability of β-Ala and to investigate the mechanism of the impact of absorbed β-Ala on the anti-oxidative ability in stee

关键词： β-Alanine Cattle Nitrogen metabolism Rumen bacterial community Rumen fermentation