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Unexpectedly large energy variations from dopant interactions in ferroelectric HfO_(2) from high-throughput ab initio calculations

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npj Computational Materials 2018年第1期4卷 45-53页

作者： Max Falkowski Christopher k.nneth Robin Materlik Alfred kersch Munich University of Applied sciences Lothstr.3480335 MunichGermany

Insight into the origin of process-related properties like small-scale inhomogeneities is key for material ***,we analyze DFT calculations of randomly doped HfO_(2) structures with si,La,and VO and relate them to the kind of production *** energies of the relevant ferroelectric Pbc2_(1) phase are compared with the competing crystallographic phases under the influence of the arising local inhomogeneities in a coarse-grained *** interaction among dopants adds to the statistical effect from the random positioning of the *** anneals after atomic layer or chemical solution deposition processes,which are short compared to ceramic process tempering,the large energy variations remain because the dopants do not *** the energy difference is the criterion for the phase stability,the large variation suggests the possibility of nanoregions and diffuse phase transitions because these local doping effects may move the system over the paraelectric-ferroelectric phase boundary.

关键词： ferroelectric dopant grain

Discovery of high-entropy ceramics via machine learning

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npj Computational Materials 2020年第1期6卷 1323-1331页

作者： kevin kaufmann Daniel Maryanovsky William M.Mellor Chaoyi Zhu Alexander s.Rosengarten Tyler J.Harrington Corey Oses Cormac Toher stefano Curtarolo k.nneth s.vecchio Department of NanoEngineering UC San DiegoLa JollaCA 92093USA Department of Cognitive science UC San DiegoLa JollaCA 92093USA Materials science and Engineering Program UC San DiegoLa JollaCA 92093USA Department of Mechanical Engineering and Materials science Duke UniversityDurhamNC 27708USA Materials science Electrical EngineeringPhysics and ChemistryDuke UniversityDurhamNC 27708USA

Although high-entropy materials are attracting considerable interest due to a combination of useful properties and promising applications,predicting their formation remains a hindrance for rational discovery of new *** approaches are based on physical intuition and/or expensive trial and error *** computational methods rely on the availability of sufficient experimental data and computational *** learning(ML)applied to materials science can accelerate development and reduce *** this study,we propose an ML method,leveraging thermodynamic and compositional attributes of a given material for predicting the synthesizability(i.e.,entropy-forming ability)of disordered metal carbides.

关键词： ceramics entropy attracting

Conversion of natural marine skeletons as scaffolds for bone tissue engineering

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Frontiers of Materials science 2013年第2期7卷 103-117页

作者： Xing ZHANG k.nneth s. vecchio Department of Bioengineering Rice University Houston Texas 77030 USA Department of NanoEngineering University of California at San Diego La Jolla California 92093 USA

Marine CaCO3 skeletons have tailored architectures created by nature, which give them structural support and other functions. For example, seashells have dense lamellar structures, while coral, cuttlebone and sea urchin spines have interconnected porous structures. In our experiments, seashells, coral and cuttlebone were hydrothermaily converted to hydroxyapatite （HAP）, and sea urchin spines were converted to Mg-substituted tricalcium phosphate, while maintaining their original structures. Partially converted shell samples have mechanical strength, which is close to that of compact human bone. After implantation of converted shell and spine samples in rat femoral defects for 6 weeks, there was newly formed bone growth up to and around the implants. some new bone was found to migrate through the pores of converted spine samples and grow inward. These results show good bioactivity and osteoconductivity of the implants, indicating the converted shell and spine samples can be used as bone defect fillers. The interconnected porous HAP scaffolds from converted coral or cuttlebone that have pore size larger than 100μm likely support infiltration of bone cells and vessels, and finally encourage new bone ingrowth.

关键词： seashell sea urchin spine coral cuttlebone hydrothermal conversion hydroxyapatite (HAP) β-tricalcium phosphate (-TCP)

Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 193-208页

作者： k.MUHAMMAD M.sARFRAZ Department of Humanities and sciences School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of Mathematics Quaid-i-Azam University

This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates. One plate remains stationary, while the other moves downward at a squeezing velocity. The space between these plates contains a Darcy-Forchheimer porous medium. A mixture of water-based fluid with gold(Au) and silicon dioxide(si O2) nanoparticles is formulated. In contrast to the conventional Fourier's heat flux equation, this study employs the Cattaneo-Christov heat flux equation. A uniform magnetic field is applied perpendicular to the flow direction, invoking magnetohydrodynamic(MHD) effects. Further, the model accounts for Joule heating, which is the heat generated when an electric current passes through the fluid. The problem is solved via NDsolve in MATHEMATICA. Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow, energy transport, and skin *** findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies. It is observed that the squeezing motion generates additional pressure gradients within the fluid, which enhances the flow rate but reduces the frictional drag. Consequently, the fluid is pushed more vigorously between the plates, increasing the flow velocity. As the fluid experiences higher flow rates due to the increased squeezing effect, it spends less time in the region between the plates. The thermal relaxation, however, abruptly changes the temperature, leading to a decrease in the temperature fluctuations.

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small-scale multi-axial hybrid simulation of a shear-critical reinforced concrete frame

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 727-743页

作者： Vahid sadeghian Oh-sung kwon Frank vecchio Department of Civil Engineering University of Toronto35 St.George St.TorontoONCanada

This study presents a numerical multi-scale simulation framework which is extended to accommodate hybrid simulation （numerical-experimental integration）. The framework is enhanced with a standardized data exchange format and connected to a generalized controller interface program which facilitates communication with various types of laboratory equipment and testing configurations. A small-scale experimental program was conducted using a six degree-of-freedom hydraulic testing equipment to verify the proposed framework and provide additional data for small-scale testing of shear- critical reinforced concrete structures. The specimens were tested in a multi-axial hybrid simulation manner under a reversed cyclic loading condition simulating earthquake forces. The physical models were 1/3.23-scale representations of a beam and two columns. A mixed-type modelling technique was employed to analyze the remainder of the structures. The hybrid simulation results were compared against those obtained from a large-scale test and finite element analyses. The study found that if precautions are taken in preparing model materials and if the shear-related mechanisms are accurately considered in the numerical model, small-scale hybrid simulations can adequately simulate the behaviour of shear-critical structures. Although the findings of the study are promising, to draw general conclusions additional test data are required.

关键词： hybrid simulation small-scale testing reinforced concrete structures, shear behaviour multi-scale modelling

Revisiting cerebral endothelial cells in Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2911-2912页

作者： Amira s.Hanafy Department of Neurosurgery University Hospital BonnBonnGermany

Alzheimer’s disease(AD)is the most common neurodegenerative disorder characterized by slow and progressive decline of cognitive and memory *** only approximately 5%of the cases,AD is familial,as often predisposed by genetic mutations(Hoogmartens et al.,2021),while sporadic AD accounts for approximately 95%of the *** amyloid cascade hypothesis is one of the fundamental hypotheses put out to explain AD pathogenesis as dysregulated homeostasis of amyloid-β(Aβ)peptides that leads to the accumulation of Aβplaques in the parenchyma,an anatomical hallmark of AD.

关键词： Alzheimer Aβ cerebral

A systematic review of progenitor survival and maturation in Parkinsonian models

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Neural Regeneration Research 2025年第11期20卷 3172-3178页

作者： Giulia Comini Eilís Dowd Pharmacology&Therapeutics and Galway Neuroscience Center University of GalwayGalwayIreland

stem cell-based brain repair is a promising emergent therapy for Parkinson's disease based on years of foundational research using human fetal donors as a cell *** current therapeutic options for patients,this approach has the potential to provide longterm stem cell–derived reconstruction and restoration of the dopaminergic input to denervated regions of the brain allowing for restoration of certain functions to *** ultimate clinical success of stem cell–derived brain repair will depend on both the safety and efficacy of the approach and the latter is dependent on the ability of the transplanted cells to survive and differentiate into functional dopaminergic neurons in the Parkinsonian *** the pre-clinical literature suggests that there is considerable variability in survival and differentiation between studies,the aim of this systematic review was to assess these parameters in human stem cell-derived dopaminergic progenitor transplant studies in animal models of Parkinson's disease.A defined systematic search of the PubMed database was completed to identify relevant studies published up to March *** screening,76 articles were included in the analysis from which 178 separate transplant studies were *** these,graft survival could be assessed in 52 studies and differentiation in 129 ***,we found that graft survival ranged froms transplanted,with a median of 51%of transplanted cells surviving in the brain;while dopaminergic differentiation of the cells ranged from 0% to 46% of cells transplanted with a median of 3%.This systematic review suggests that there is considerable scope for improvement in the differentiation of stem cell-derived dopaminergic progenitors to maximize the therapeutic potential of this approach for patients.

关键词： cell replacement therapy differentiation embryonic stem cells graft induced pluripotent stem cells Parkinson's disease survival transplant

Deciphering the mechanobiology of microglia in traumatic brain injury with advanced microsystems

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Neural Regeneration Research 2025年第8期20卷 2304-2306页

作者： Anthony Procès sylvain Gabriele Univ.Grenoble Alpes InsermU1216Grenoble Institut des NeurosciencesGrenobleFrance Mechanobiology&Biomaterials Group CIRMAPResearch Institute for BiosciencesUniversity of MonsMonsBelgium

Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary *** minutes ... 详细信息

关键词： traumatic injury damage

COEXIsTENCE FOR MULTIPLE LARGEsT REPRODUCTION RATIOs OF A MULTI-sTRAIN sIs EPIDEMIC MODEL

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Acta Mathematica scientia 2016年第5期36卷 1524-1530页

作者： Yoshiaki MUROYA Eleonora MEssINA Elvira RUssO Antonia vecchio Department of Mathematics Waseda University Dipartimento di Matematica e Applicazioni Università degli Studi di Napoli "Federico Ⅱ"-Via Cintia Istituto per Applicazioni del Calcolo "M. Picone" Sede di Napoli-CNR-Via P.Castellino

In this paper, to complete the global dynamics of a multi-strains sIs epidemic model, we establish a precise result on coexistence for the cases of the partial and complete duplicated multiple largest reproduction rat... 详细信息

关键词： multi-strains sIs epidemic model global attractivity Lyapunov function coexistence