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Concurrent generation and amplification of longitudinal and bending waves using defective phononic crystals

Applied Mathematics and Mechanics(English Edition) 2025年第2期46卷 269-288页

作者： s.h.JO Department of Mechanical Robotics and Energy Engineering Dongguk University

Defective phononic crystals (PnCs) have enabled spatial localization and quantitative amplification of elastic wave energy. Most previous research has focused on applications such as narrow-bandpass filters, ultrasonic sensors, and piezoelectric energy harvesters, typically operating under the assumption of an external elastic wave incidence. Recently, a novel approach that uses defective PnCs as ultrasonic actuators to generate amplified waves has emerged. however, the existing studies are limited to the generation of either longitudinal or bending waves, with no research addressing the concurrent generation of both. hence, this paper proposes a straightforward methodology for the concurrent generation and amplification of both wave types utilizing defect modes at independent defect-band frequencies. Bimorph piezoelectric elements are attached to the defect, with each element connected to independent external voltage sources. By precisely adjusting the magnitude and temporal phase differences between the voltage sources, concurrently amplified wave generation is achieved. The paper highlights the advantages of the proposed analytical model. This model is both computationally timeefficient and accurate, in comparison with the COMsOL simulation results. For instance,in case studies, the analytical model reduces the computational time from one hour to mere seconds, while maintaining acceptable error rates of 1%in peak frequencies. This concurrent wave-generation methodology opens new avenues for applications in rotating machinery fault diagnosis, structural health monitoring, and medical imaging.

关键词： phononic crystal (PnC) defect concurrent generation piezoelectric ultrasonic actuator O328 O346

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Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI h.GhANDVAR E.JUMAEV s.KhATIR T.CUONG-LE school of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and science Center for Engineering Application and Technology solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANsYs, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： double curved beam finite element method functionally graded porous (FGP) material intermediate straight beam O313 vibration analysis

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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hOssEINI O.BALILAshAKI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词： cylindrical cavity O353.4 point source porous medium stress concentration wave-field transformation

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Multi-Objective optimization for stable and efficient cargo transportation of partial space elevator

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Defence Technology 2025年第2期44卷 17-29页

作者： Gefei shi Zheng h.Zhu school of Aeronautics and Astronautics Sun Yat-sen University shenzhen Key Laboratory of Intelligent Microsatellite Constellation Department of Mechanical Engineering York University

This paper proposed a new libration decoupling analytical speed function(LD-AsF) in lieu of the classic analytical speed function to control the climber's speed along a partial space elevator to improve libration stability in cargo transportation. The LD-AsF is further optimized for payload transportation efficiency by a novel coordinate game theory to balance competing control objectives among payload transport speed, stable end body's libration, and overall control input via model predictive control. The transfer period is divided into several sections to reduce computational burden. The validity and efficacy of the proposed LD-AsF and coordinate game-based model predictive control are demonstrated by computer simulation. Numerical results reveal that the optimized LD-AsF results in higher transportation speed, stable end body's libration, lower thrust fuel consumption, and more flexible optimization space than the classic analytical speed function.

关键词： Partial space elevator stable transportation Libration decoupling analytical speed function Coordinate game Model predictive control Pareto optimization

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A mild, configurable, flexible CoNi-LDh(v)/Zn battery based on h-vacancy-induced reversible Zn^(2+) intercalation

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Journal of Energy Chemistry 2025年第1期100卷 498-508页

作者： Xinyue Cheng Dingsheng Wu hao Gao Qingqing Wang Pengfei Lv sam s.Yoon Qufu Wei Key Laboratory of Eco–textiles Ministry of EducationJiangnan UniversityWuxi 214122JiangsuChina School of Mechanical EngineeringKorea UniversitySeoul 136–713Republic of Korea Received 12 August 2024Revis

Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage ***,the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide (CoNi-LDh) as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline ***,CoNi-LDh nanosheets enriched with h vacancies (CoNi-LDh(v)) were constructed on a flexible carbon cloth (CC) substrate via electrochemical deposition and *** Zn-based battery comprising CoNi-LDh(v)@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnsO4electrolyte (ph=4).The battery delivered an excellent specific capacity (225 mA h g^(-1),0.26 mA h cm^(-2)),acceptable cycling stability(53.9%,900 cycles),and high discharging *** abundant h vacancies served as active sites for the reversible intercalation of Zn^(2+)and the extravasation of NO_(3)-generated channels and space for Zn^(2+)transport and storage,together enabling an excellent Zn^(2+)storage ***,a sandwich-structured solid-state CoNi-LDh(v)@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical *** a proof of concept,the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 ***,the flexible battery displayed outstanding customizability,maintaining an open-circuit voltage of 1.42 V even after being cut *** proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.

关键词： CoNi/Zn battery h vacancies Mild aqueous electrolyte Tailorable battery Wearable energy storage device

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Iron-promoted zirconia-alumina supported Ni catalyst for highly efficient and cost-effective hydrogen production via dry reforming of methane

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Journal of Environmental sciences 2025年第2期148卷 274-282页

作者： Ahmed s.Al-Fatesh Naitik Patel Vijay Kumar srivastava Ahmed I.Osman David W.Rooney Anis h.Fakeeha Ahmed E.Abasaeed Mohammed F.Alotibi Rawesh Kumar Chemical Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia Department of Chemistry Indus UniversityAhmedabadGujarat 382115India school of Chemistry and Chemical Engineering Queen’s University BelfastBelfast BT95AGNorthern IrelandUK Institute of Refining and Petrochemicals Technologies King Abdulaziz City for Science and Technology(KACST)P.O.Box 6086Riyadh 11442Kingdom of Saudi Arabia

Developing cost-effective and high-performance catalyst systems for dry reforming of methane(DRM)is crucial for producing hydrogen(h_(2))***,we investigate using iron(Fe)as a promoter and major alumina support in Ni-based catalysts to improve their DRM *** addition of iron as a promotor was found to add reducible iron species along with reducible NiO species,enhance the basicity and induce the deposition of oxidizable *** incorporating 1 wt.%Fe into a 5Ni/10ZrAl catalyst,a higher CO_(2) interaction and formation of reducible"NiO-species having strong interaction with support"was observed,which led to an∼80%h_(2) yield in 420 min of Time on stream(TOs).Further increasing the Fe content to 2 wt.%led to the formation of additional reducible iron oxide species and a noticeable rise in h_(2) yield up to 84%.Despite the severe weight loss on Fe-promoted catalysts,high h_(2) yield was maintained due to the proper balance between the rate of Ch_(4) decomposition and the rate of carbon deposit ***,incorporating 3 wt.%Fe into the 5Ni/10ZrAl catalyst resulted in the highest CO_(2) interaction,wide presence of reducible NiO-species,minimumgraphitic deposit and an 87%h_(2) *** findings suggest that ironpromoted zirconia-alumina-supported Ni catalysts can be a cheap and excellent catalytic system for h_(2) production via DRM.

关键词： Dry reforming of methane Coke resistant hydrogen production Cheap catalyst Fe-promoted catalyst

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La3+ substitution-adjusted magnetic and optical properties with enhanced photocatalytic activity and stability of copper zinc nickel ferrites for wastewater treatment applications

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Journal of Rare Earths 2025年第2期43卷 319-328页

作者： N.s.Al-Bassami General studies Department Jubail Industrial College

Copper-zinc-nickel（Cu-Zn-Ni） ferrite nanoparticles are used for wastewater treatment ***,low degradation efficiency and stability are two main issues that make them unsuitable for actual production *** this paper,the citrate-nitrate auto-combustion method was applied for the formation of Cu0.5Zn0.25Ni0.25LaxFe2-xO4;（0≤x≤0.1;step 0.02）(CZNL) *** the substitution process entails the replacement of a small ion with a larger one,the lattice constant and crystallite size does not exhibit a consistent incremental *** behavior is justified and *** size of all the CZNL ferrite nanoparticles is in the range of 8-12 nm,and the lattice constant is in the range of 8.6230 to 8.4865 *** morphological analysis conducted using field emission-scanning electron microscopy（FE-sEM） reveals that the CZNL exhibits agglomerated spherical *** energy dispersive X-ray spectrameter（EDAX） analysis was employed to confirm the elemental composition of CZNL *** the process entails the substitution of Fe3+magnetic ions with nonmagnetic ions La3+,the magnetic parameters of CZNL nanoferrites show a general decreasing trend as *** 20 K,saturation magnetization Ms shows an overall drop in its values from 59.302 emu/g at x=0.0-41.295 emu/g at x=0.1,the smallest value of 37.87 emu/g is recorded at x=*** highest coercivity（hc=125.9 Oe） and remanence（Mr=13.32 emu/g） are recorded for x=0.08 and x=0.04 nanoferrite,*** band gap of all the CZNL nanoferrites was determined using the Kubelka-Munk function and Tauc plot for direct permitted *** doping modifies the band gap（within 1.86-1.75 eV）,increases light absorption,induces efficient e/h separation and charge migration to *** nanoferrite Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4achieves a degradation efficiency of 97.3% for methylene blue（MB） dye removal after just 60 *** five recycling processes,the nanoc

关键词： Copper-zinc-nickel Ferrite Photocatalytic properties Rare earths Wastewater treatment

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Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

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Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

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Comparative chemical sensor for detection of chromium(Ⅵ) in aqueous solution

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Optoelectronics Letters 2025年第1期21卷 21-27页

作者： sura h.AL-REkaBI A.A.ALWAhIB Electrical Technique Department Al Suwayrah Technical Institute Middle Technical University Laser and Optoelectronics Department University of Technology-Iraq

A process for purifying aqueous solutions containing heavy and toxic metals such as chromium（Cr） has been investigated. One of the extremely harmful pollutants in rivers and seawater is the heavy metal ions due to their direct impacts on human, animals and plants are hexavalent Cr（Ⅵ）. Consequently, highly sensitive sensor to detect Cr is essential. surface plasmon resonance（sPR） technique has attracted huge research interest in detecting heavy metals specifically. In this study, three types of prism-based sPR sensor, gold（Au）/silver（Ag）, Au/polyaniline（PANI） and Au/titanium dioxide（TiO2） nanostructured films, are investigated as potential sensing material to detect the presence of Cr（Ⅵ） ions in water. The base Au layer with thickness of 48.3 nm is deposited on a glass slide for all sensors. For Au/Ag, Au/PANI nanofibers and Au/TiO2sensor films, the Cr（Ⅵ） concentration is varied from 1 ppm to 15 ppm with sensitivity of 0.270 °ppm-1, 0.082 °ppm-1and 0.039 °ppm-1, respectively. Based on these results, the Au/PANI nanofibers are the most sensitive to Cr（Ⅵ） among the tested sensing materials.

关键词： Titanium dioxide

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