318 results match your criteria: "Institute of Applied Mathematics and Mechanics[Affiliation]"

Study on Confined Water in Flexible Graphene/GO Nanochannels.

J Phys Chem B

June 2024

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Yanchang Road 149, Shanghai 200444, China.

The structural evolution of flexible nanochannels within a 2D material membrane, influenced by the ingress of water molecules, plays a crucial role in the membrane's filtration and structural stability. However, the experimental observation of nanoscale water is challenging, and current studies mostly focus on rigid nanochannels. Further investigation on the nanoconfined water is urgently needed, considering the flexibility and deformation of the channel.

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Effect of the degree of an initial mutant in Moran processes in structured populations.

Phys Rev E

April 2024

Institute of Applied Mathematics and Mechanics, University of Warsaw, 02-097 Warsaw, Poland.

We study effects of the mutant's degree on the fixation probability, extinction, and fixation times in Moran processes on Erdös-Rényi and Barabási-Albert graphs. We performed stochastic simulations and used mean-field-type approximations to obtain analytical formulas. We showed that the initial placement of a mutant has a significant impact on the fixation probability and extinction time, while it has no effect on the fixation time.

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The Impact of the Fluid-Solid Coupling Behavior of Macro and Microstructures in the Spiral Cochlea on Hearing.

J Biomech Eng

June 2024

School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China.

The cilia of the outer hair cells (OHCs) are the key microstructures involved in cochlear acoustic function, and their interactions with lymph in the cochlea involve complex, highly nonlinear, coupled motion and energy conversions, including macroscopic fluid-solid coupling. Recent optical measurements have shown that the frequency selectivity of the cochlea at high sound levels is entirely mechanical and is determined by the interactions of the hair bundles with the surrounding fluid. In this paper, an analytical mathematical model of the spiral cochlea containing macro- and micromeasurements was developed to investigate how the phonosensitive function of OHCs' motions is influenced by the macrostructural and microstructural fluid-solid coupling in the spiral cochlea.

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Investigation on the mechanical integrity of a PEO-based polymer electrolyte in all-solid-state lithium batteries.

Phys Chem Chem Phys

March 2024

Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, China.

Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) have good ionic conductivity and flexibility, and is a key component of all-solid-state lithium batteries (ASSLBs). Therefore, the mechanical integrity of PEO-based SPEs during cell operation needs to be urgently evaluated. Here, we conducted a series of tensile and shear adhesion performance tests on PEO-LiTFSI electrolyte and LiFePO electrode adhesion samples at various temperatures and quenching rates.

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Symmetry constraints on the orientation dependence of high-order elastic constants for the hexagonal boron nitride monolayer.

Phys Chem Chem Phys

March 2024

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

Group theory is a powerful tool to explore fundamental symmetry constraints for the physical properties of crystal structures, it is well-known that only a few components of the elastic constants are independent due to the symmetry constraint. This work further applies group theory to derive constraint relationships for high-order elastic constants with respect to the orientation angle, where the constraint relationships are more explicit than the traditional tensor transformation law. These analytic symmetry constraints are adopted to explain the molecular dynamics simulation results, which disclose that the high-order elastic constants are highly anisotropic with an anisotropy percentage of up to 25% for the hexagonal boron nitride monolayer.

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Explicit mutual information for simple networks and neurons with lognormal activities.

Phys Rev E

January 2024

Department of Mathematics, Informatics, and Mechanics, Institute of Applied Mathematics and Mechanics, University of Warsaw, Ulica Banacha 2, 02-097 Warsaw, Poland.

Networks with stochastic variables described by heavy-tailed lognormal distribution are ubiquitous in nature, and hence they deserve an exact information-theoretic characterization. We derive analytical formulas for mutual information between elements of different networks with correlated lognormally distributed activities. In a special case, we find an explicit expression for mutual information between neurons when neural activities and synaptic weights are lognormally distributed, as suggested by experimental data.

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Buoyancy-driven attraction of active droplets.

J Fluid Mech

February 2024

Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics and J.M.Burgers Center for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.

For dissolving active oil droplets in an ambient liquid, it is generally assumed that the Marangoni effect results in repulsive interactions, while the buoyancy effects caused by the density difference between the droplets, diffusing product and the ambient fluid are usually neglected. However, it has been observed in recent experiments that active droplets can form clusters due to buoyancy-driven convection (Krüger , vol. 39, 2016, pp.

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Vibration modes of three-dimensional spiral cochlea covering the organ of Corti.

Comput Methods Biomech Biomed Engin

February 2024

Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, China.

So far, explaining the mechanism on active phonosensitive amplification in the cochlea is a major and difficult medical question. Among them, one of the key problems is that the motion pattern of the organ of Corti (OC) is still unknown. To this end, a multi-scale cochlear model including a three-dimensional spiral OC was established based on CT data and light source imaging experimental data, which complete combined the macroscopic and microscopic structure.

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A molecular arm: the molecular bending-unbending mechanism of integrin.

Biomech Model Mechanobiol

June 2024

Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200072, China.

The balance of integrin activation and deactivation regulates its function and mediates cell behaviors. Mechanical force triggers the unbending and activation of integrin. However, how an activated and extended integrin spontaneously bends back is unclear.

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Regional patient transfer patterns matter for the spread of hospital-acquired pathogens.

Sci Rep

January 2024

Institute for Medical Epidemiology, Biometrics and Informatics (IMEBI), Interdisciplinary Centre for Health Sciences, Medical School of the Martin Luther University Halle-Wittenberg, 06108, Halle, Saale, Germany.

Pathogens typically responsible for hospital-acquired infections (HAIs) constitute a major threat to healthcare systems worldwide. They spread via hospital (or hospital-community) networks by readmissions or patient transfers. Therefore, knowledge of these networks is essential to develop and test strategies to mitigate and control the HAI spread.

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Force-Regulated Spontaneous Conformational Changes of Integrins αβ and αβ.

ACS Nano

January 2024

Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

Integrins are cell surface nanosized receptors crucial for cell motility and mechanosensing of the extracellular environment, which are often targeted for the development of biomaterials and nanomedicines. As a key feature of integrins, their activity, structure and behavior are highly mechanosensitive, which are regulated by mechanical forces down to pico-Newton scale. Using single-molecule biomechanical approaches, we compared the force-modulated ectodomain bending/unbending conformational changes of two integrin species, αβ and αβ.

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Cooperativity, Information Gain, and Energy Cost During Early LTP in Dendritic Spines.

Neural Comput

January 2024

College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences and Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Warsaw 02-097, Poland.

We investigate a mutual relationship between information and energy during the early phase of LTP induction and maintenance in a large-scale system of mutually coupled dendritic spines, with discrete internal states and probabilistic dynamics, within the framework of nonequilibrium stochastic thermodynamics. In order to analyze this computationally intractable stochastic multidimensional system, we introduce a pair approximation, which allows us to reduce the spine dynamics into a lower-dimensional manageable system of closed equations. We found that the rates of information gain and energy attain their maximal values during an initial period of LTP (i.

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Information encoded in volumes and areas of dendritic spines is nearly maximal across mammalian brains.

Sci Rep

December 2023

Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Warsaw, Poland.

Many experiments suggest that long-term information associated with neuronal memory resides collectively in dendritic spines. However, spines can have a limited size due to metabolic and neuroanatomical constraints, which should effectively limit the amount of encoded information in excitatory synapses. This study investigates how much information can be stored in the population of sizes of dendritic spines, and whether it is optimal in any sense.

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Flexible nanomechanical bit based on few-layer graphene.

Phys Chem Chem Phys

January 2024

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

Mechanical computers have gained intense research interest at size scales ranging from nano to macro as they may complement electronic computers operating in extreme environments. While nanoscale mechanical computers may be easier to integrate with traditional electronic components, most current nanomechanical computers are based on volatile resonator systems that require continuous energy input. In this study, we propose a non-volatile nanomechanical bit based on the quasi-stable configurations of few-layer graphene with void defects, and demonstrate its multiple quasi-stable states by deriving an analytic relationship for the void configuration based on a competition between the bending energy and the cohesive energy.

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External Pressure Affecting Dendrite Growth and Dissolution in Lithium Metal Batteries During Cycles.

ACS Appl Mater Interfaces

December 2023

Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China.

Lithium (Li) metal has garnered significant attention as the preferred anode for high-energy lithium metal batteries. However, safety concerns arising from the growth of Li dendrites have hindered the advancement of Li metal batteries. In this study, we first elucidate the impact of external pressure and internal stress on dendrite growth and dissolution behavior of Li metal batteries during continuous charging-discharging cycles, employing a developed electrochemomechanical phase-field model.

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Optimal design and nonlinear dynamic characteristics of titanium /steel drill pipe composite drill string for ultra-deep drilling.

Sci Rep

November 2023

State Key Laboratory for Performance and Structural Safety of Petroleum Tubular Goods and Equipment Materials, CNPC Tubular Goods Research Institute, No. 89, Jinye 2nd Road, Xi'an, 710077, Shaanxi, China.

Titanium drill pipe have promising application prospects in ultra-deep drilling, but the nonlinear dynamic characteristics of composite drill strings are very complex. It is very important to use titanium drill pipe safely, economically, and effectively in the drilling process. In this paper, different schemes of the titanium/steel drill pipe composite drill string was designed, and the statics and dynamics characteristics of these composite drill strings were analyzed.

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The effect of intrinsic strain on the thermal expansion behavior of Janus MoSSe nanotubes: a molecular dynamic simulation.

Nanotechnology

December 2023

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

In this study, we conducted molecular dynamic simulations to investigate the thermal expansion behavior of Janus MoSSe nanotubes. We focused on understanding how the intrinsic strain in these nanotubes affects their thermal expansion coefficient (TEC). Interestingly, we found that Janus MoSSe nanotubes with sulfur (S) on the outer surface (MoSeS) exhibit a different intrinsic strain compared to those with selenium (Se) on the outer surface (MoSSe).

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Study on damage of the macrostructure of the cochlea under the impact load.

Proc Inst Mech Eng H

December 2023

School of Mechanics and Engineering Science, Shanghai University, Shanghai, China.

Due to the tiny and delicate structure of the cochlea, the auditory system is the most sensitive to explosion impact damage. After being damaged by the explosion impact wave, it usually causes long-term deafness, tinnitus, and other symptoms. To better understand the influence of impact load on the cochlea and basilar membrane (BM), a three-dimensional (3D) fluid-solid coupling finite element model was developed.

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Machine learning accelerated search for the impact limit of the graphene/aluminum alloy whipple structure.

Nanotechnology

November 2023

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

This paper proposes a Whipple structure to enhance the impact resistance of graphene/aluminum alloy composites by varying the interlayer spacing between graphene and aluminum alloy. The increased interlayer spacing provides more deformation space for the graphene to absorb more deformation energy, and enables the formation of a debris cloud from the bullet fragments and graphene fragments, significantly reducing the impact energy per unit area of the next material. The impact limit serves as a critical metric for assessing the impact resistance of the Whipple structure.

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A susceptible-infectious-susceptible (SIS) model for simulating healthcare-acquired infection spread within a hospital and associated community is proposed. The model accounts for the stratification of in-patients into two susceptibility-based risk groups. The model is formulated as a system of first-order ordinary differential equations (ODEs) with appropriate initial conditions.

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Article Synopsis
  • Wilson disease (WD) is caused by mutations in the ATP7B gene, leading to copper overload in the liver and brain, which can result in severe health issues.
  • A mutant strain of Caenorhabditis elegans was created to study this condition, showing significant Cu sensitivity, stunted development, and other health impairments due to a specific ATP7B variant.
  • The cua-1 mutant strain serves as a valuable experimental model for understanding copper toxicity in WD and testing potential therapeutic approaches.
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Nanobubble-induced significant reduction of the interfacial thermal conductance for few-layer graphene.

Phys Chem Chem Phys

November 2023

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

The heat transport properties of van der Waals layered structures are crucial for ensuring the reliability and longevity of high-performance optoelectronic equipment. Owing to the two-dimensional nature of atomic layers, the presence of bubbles is commonly observed within these structures. Nevertheless, the effect of bubbles on the interfacial thermal conductance remains unclear.

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Nonlinearity induced negative Poisson's ratio of two-dimensional nanomaterials.

Nanotechnology

November 2023

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, People's Republic of China.

Materials exhibiting a negative Poisson's ratio have garnered considerable attention due to the improved toughness, shear resistance, and vibration absorption properties commonly found in auxetic materials. In this work, the nonlinear effect on the Poisson's ratio was derived theoretically and verified by first-principle calculations and molecular dynamics simulations of two-dimensional nanomaterials including graphene and hexagonal boron nitride. The analytic formula explicitly shows that the Poisson's ratio depends on the applied strain and can be negative for large applied strains, owing to the nonlinear interaction.

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Vacancy defects impede the transition from peapods to diamond: a neuroevolution machine learning study.

Phys Chem Chem Phys

September 2023

Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Frontier Science Center of Mechanoinformatics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, P. R. China.

Exploration of novel carbon allotropes has been a central subject in materials science, in which carbon peapods hold great potential as a precursor for the development of new carbon allotropes. To enable precise large-scale molecular dynamics simulations, we develop a high-accurate and low-cost machine-learned potential (MLP) for carbon materials using the neuroevolution potential framework. Based on the MLP, we conduct an investigation into the structural transitions of peapod arrays under high-temperature and high-pressure conditions and disclose the impact of vacancy defects.

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Pathogenic mechanism analysis of cochlear key structural lesion and phonosensitive hearing loss.

Biomech Model Mechanobiol

February 2024

School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200072, People's Republic of China.

Article Synopsis
  • Direct experimental measurement on the human cochlea is challenging due to ethical concerns and its complex structure, leading to the use of the finite element method (FEM) for research.
  • A 3D finite element model of the cochlea was developed to study the impacts of conditions like basilar membrane damage, round window sclerosis, and perilymph fistula on hearing.
  • The findings enhance understanding of cochlear biomechanics and could inform clinical approaches to diagnosing and treating hearing loss.
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