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Journal of Materials Science & Technology 2021年第23期82卷 105-113页

作者： Yue Zhou William G.Fahrenholtz Joseph Graham gregory E.hilmas Department of Materials Science and Engineering Missouri University of Science and TechnologyRollaMO 65409USA

Lattice thermal conductivities of zirconium carbide(ZrC_(x),x=1,0.75 and 0.5)ceramics with different carbon vacancy concentrations were calculated using a combination of first-principles calculations and the Debye-Callaway *** Gruneisen parameters,Debye temperatures,and phonon group velocities were deduced from phonon dispersions of ZrC_(x) determined using first-principles *** addition,the effects of average atomic mass,grain size,average atomic volume and Zr isotopes on the lattice thermal conductivities of ZrC_(x) were analyzed using phonon scattering *** lattice thermal conductivity decreased as temperature increased for ZrC,ZrC_(0.75) and ZrC_(0.5)(Zr2 C),and decreased as carbon vacancy concentration ***,ZrC_(x) can be tailored from a thermal conducting material for ZrC with high lattice thermal conductivity to a thermal insulating material for ZrC_(0.5) with low lattice thermal ***,it opens a window to tune the thermal properties of ZrC_(x) by controlling the carbon vacancy content.

关键词： Zirconium carbide Lattice thermal conductivity Theoretical study First-principle calculations

Anisotropic thermal expansion in high-entropy multicomponent AlB_(2)-type diboride solid solutions

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International Journal of Extreme Manufacturing 2023年第1期5卷 331-343页

作者： Frédéric Monteverde Mattia Gaboardi Federico Saraga Lun Feng William Fahrenholtz gregory hilmas National Research Council of Italy Institute of Science Technology and Sustainability for CeramicsFaenza 48018RAItaly Elettra—Sincrotrone Trieste S.C.P.A Strada Statale 14—Km 1635 in AREA Science ParkBasovizza 34149TriesteItaly Missouri University of Science and Technology RollaMO 65409United States of America AUREL Spa I-47015(ModiglianaItaly) BLUE ORIGIN 98302(KentWashington US).

High-entropy(HE)ultra-high temperature ceramics have the chance to pave the way for future applications propelling technology advantages in the fields of energy conversion and extreme environmental *** others,HE diborides stand out owing to their intrinsic anisotropic layered structure and ability to withstand ultra-high ***,we employed in-situ high-resolution synchrotron diffraction over a plethora of multicomponent compositions,with four to seven transition metals,with the intent of understanding the thermal lattice expansion following different composition or synthesis *** a result,we were able to control the average thermal expansion(TE)from 1.3×10^(−6)to 6.9×10^(−6)K^(−1)depending on the combination of metals,with a variation of in-plane to out-of-plane TE ratio ranging from 1.5 to 2.8.

关键词： ultra-high temperature ceramics borides high-entropy ceramics spark plasma sintering synchrotron diffraction anisotropic thermal expansion

Thermodynamic analysis of metal segregation in dual phase high entropy ceramics

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Journal of Materiomics 2024年第4期10卷 889-895页

作者： Steven M.Smith II William G.Fahrenholtz gregory E.hilmas Stefano Curtarolo Missouri University of Science and Technology Materials Science and Engineering DepartmentRollaMO65409USA Duke University Department of Mechanical Engineering and Materials ScienceDurhamNC27708USA Duke University Center of Autonomous Materials DesignDurhamNC27708USA

Equilibrium Gibbs'free energy calculations were used to determine metal segregation trends between boride and carbide solid solutions containing two metals that are relevant to dual phase high entropy *** model predicted that Ti had the strongest tendency to segregate to the boride phase followed by Zr,Nb,Mo,V,Hf,and Ta,which matches experimental results of measured *** ratio of a metal in the carbide phase to the content of the same metal in the corresponding metal boride had a linear trend with the change in standard Gibbs'free energy of reaction for a metal carbide reacting with B_(4)C to produce its corresponding metal boride and *** proposed model was used to predict the changes in standard Gibbs'free energy for CrC→CrB_(2) to be−260 kJ and WC→WB_(2) to be 148 kJ,which indicates that Cr has the strongest segregation to the boride and W has the strongest segregation to the *** proposed model can be used to estimate the segregation of metals in dual phase high entropy boride-carbide ceramics of any boride/carbide ratio or metal content.

关键词： Dual phase High entropy ceramic Boride Carbide Thermodynamics

Soluble epoxide hydrolase:a next-generation drug target for Alzheimer's disease and related dementias

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Neural Regeneration Research 2025年第9期20卷 2585-2586页

作者： Andrew gregory Chengyun Tang Fan Fan Department of Physiology Medical College of GeorgiaAugusta UniversityAugustaGAUSA

Alzheimer's disease(AD)and Alzheimer's diseaserelated dementias(ADRD)represent a significant public health challenge,with projections indicating a substantial increase in affected individuals due to the aging global *** the World Health Organization,AD/ADRD has affected more than 55 million individuals worldwide,with an additional 10 million cases diagnosed each year.

关键词： Alzheimer population drug

A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn J.W.So Konstantin Feinberg Marina Manoraj Jenny Cheung Jennifer Zhang Kaveh Mirmoeini JPaul Santerre Tessa Gordon gregory HBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

Optical monitoring of particle aggregates

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Journal of Environmental Sciences 2009年第1期21卷 2-7页

作者： John gregory Department of Civil Environmental and Geomatic EngineeringUniversity College London

Methods for monitoring particle aggregation are briefly reviewed. Most of the techniques are based on some form of light scattering and may be greatly dependent on the optical properties of aggregates, which are not generally known. As fractal aggregates grow larger their density can become very low and this has important practical consequences for light scattering. For instance, the scattering coefficient may be much less than for solid objects, which means that the aggregates can appear much smaller than their actual size by a light transmission method. Also, for low-density objects, a high proportion of the scattered light energy is within a small angle of the incident beam, which may also be relevant for measurements with aggregates. Using the ＂turbidity fluctuation＂ technique as an example, it is shown how the apparent size of hydroxide flocs depends mainly on the included impurity particles, rather than the hydroxide precipitate itself. Results using clay suspensions with hydrolyzing coagulants and polymeric floceulants under different string conditions are discussed.

关键词： monitoring method flocculation turbidity fluctuation

Time-first approach for land cover mapping using big Earth observation data time-series in a data cube-a case study from the Lake Geneva region(Switzerland)

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Big Earth Data 2024年第3期8卷 435-466页

作者： gregory Giuliani Institute for Environmental Sciences EnviroSPACE labUniversity of GenevaGenevaSwitzerland United Nations Environment Programme Division of Early Warning and AssessmentGenevaSwitzerland

Accurate,consistent,and high-resolution Land Use&Cover(LUC)information is fundamental for effectively monitoring landscape dynamics and better apprehending drivers,pressures,state,and impacts on land ***,the availability of such national products with high thematic accuracy is still limited and consequently researchers and policymakers are constrained to work with data that do not necessarily reflect on-the-ground realities impending to correctly capture details of landscape features as well as limiting the identification and quantification of drivers and rate of ***,we took advantage of the Switzerland’s official LUC statistical sampling survey and dense time-series of Sentinel-2 data,combining them with Machine and Deep Learning methods to produce an accurate and high spatial resolution land cover map over the Lake Geneva *** suggest that time-first approach is a valuable alternative to space-first approaches,accounting for the intra-annual variability of classes,hence improving classification *** demonstrate that Deep Learning methods outperform more traditional Machine Learning ones such as Random Forest,providing more accurate predictions with lower *** produced land cover map has a high accuracy,an improved spatial resolution,while at the same time preserving the statistical significance(*** proportion)of the official national *** work paves the way towards the objective to produce a yearly high resolution land cover map of Switzerland and potentially implement a continuous land change monitoring *** further work is required to properly address challenges such as the need for increased temporal resolution for LUC information or the quality of training samples.

关键词： Land cover Sentinel-2 timeseries SITS Arealstatistik

Global weirding at mass extinction horizons

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National Science Review 2024年第1期11卷 10-12页

作者： gregory J.Retallack Department of Earth Sciences University of Oregon

A strong motivation for studying mass extinctions is understanding how current climatic and biodiversity crises will affect creatures living on land such as ourselves. Perhaps the question is: how bad can it get? In that case, terrestrial Permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

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Assessing risks from mining-induced ground movements near gas wells

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International Journal of Mining Science and Technology 2020年第1期30卷 11-16页

作者： Christopher Mark gregory M.Rumbaugh Mine Safety and Health Administration PittsburghPAUSA

The proliferation of unconventional gas well development in the Northern Appalachian coalfields has raised a number of mine safety *** wells,which extract gas from deep shale formations,are characterized by gas volumes and pressures that are significantly higher than those observed at many conventional *** gas is composed largely of methane as well as other *** of planned and actively producing wells penetrate protective coal pillars or barriers within active mine boundaries,including chain pillars located between longwall *** released from a well damaged by mining-induced ground movements could pose a risk to miners by flowing into the mine *** mining-induced ground movements that may cause well damage include conventional subsidence,non-conventional subsidence(*** plane slip),pillar failure,and floor *** paper describes the known risk factors for each of the four failure *** includes a framework that can guide the risk assessment process when mining takes place near gas or oil wells.

关键词： Gas well Subsidence Coal protection pillar Risk matrix Longwall mining

From common gardens to candidate genes:an elegant case of homoploid hybrid speciation

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Molecular Plant 2021年第2期14卷 200-201页

作者： gregory L.Owens Department of Biology University of VictoriaVictoriaBCCanada

Homoploid hybrid speciation(HHS),where genetic contributions from two species combine to produce a third species without a change in pioidy,remains an intriguing and enigmatic evolutionary *** studies in the past decade have shown that introgression and admixture between species is common,and yet well documented cases of HHS remain rare(Schumer et al.,2014;Marques et al.,2019).This strikes at a key feature of HHS;it is a far higher bar to prove that hybridization was critical for speciation than it is to show that introgression *** former requires us to know how reproductive isolation(RI)is achieved,identify hybrid ancestry,and definitively link hybrid ancestry with reproductive *** this in mind,the work by Wang et al.(2020)fully documenting a case of HHS is particularly impressive in terms of both the scope and clarity of the results.

关键词： al. combine intro