Some recent progress on the complexity of lattice problems

博士后 计算材料 材料模拟

As a postdoctoral researcher specializing in computational materials

science, I have always been fascinated by the complexity of materials

and how they behave under different conditions. My research

involves using computer simulations to study the properties of

materials at the atomic and molecular level, allowing us to better

understand their behavior and predict their performance in various

applications. This field combines elements of physics, chemistry, and

engineering to provide valuable insights into the structure and

behavior of materials, leading to advancements in technology and

scientific knowledge.

作为一名专门从事计算材料科学的博士后研究员，我一直对材料的复杂性及其在不同条件下的行为感到着迷。我的研究涉及使用计算机模拟研究材料在原子和分子水平上的性质，从而使我们更好地了解它们的行为，并预测它们在各种应用中的性能。这一领域结合了物理学、化学和工程学的元素，为我们提供了宝贵的见解，以了解材料的结构和行为，从而推动技术和科学知识的进步。

Computational materials science has revolutionized the way we study

5篇英语精读文章+翻译

1.Can We Know the Universe? - Reflections on a Grain of Salt

Carl Sagan

Science is a way of thinking much more than it is a body of

knowledge. Its goal is to find out how the world works, to seek

what regularities there may be, to penetrate to the connections

of things - from sub-nuclear particles, which may be the

constituents of all matter, to living organisms, the human social

community, and thence to the cosmos as a whole. Our intuition

is by no means an infallible guide. Our perceptions may be

distorted by training and prejudice or merely because of the

limitations of our sense organs, which, of course, perceive directly

but a small fraction of the phenomena of the world.

Even so straightforward a question as whether in the

absence of friction a pound of lead falls faster than a grain of fluff

NanoscaleCoatingofLiMO2(M=Ni,Co,Mn)NanobeltswithLi+‑ConductiveLi2TiO3:TowardBetterRateCapabilitiesforLi-IonBatteriesJunLu,QingPeng,*WeiyangWang,CaiyunNan,LihongLi,andYadongLiDepartmentofChemistry,StateKeyLaboratoryofLow-DimensionalQuantumPhysics,TsinghuaUniversity,Beijing100084*SSupportingInformationABSTRACT:ByusinganovelcoatingapproachbasedonthereactionbetweenMC2O4·xH2OandTi(OC4H9)4,aseriesofnanoscaleLi2TiO3-coatedLiMO2nanobeltswithvariedNi,Co,andMncontentswaspreparedforthefirsttime.Thecomplete,thinLi2TiO3coatinglayerstronglyadherestothehostmaterialandhasa3DdiffusionpathforLi+ions.ItisdopedwithNi2+andCo3+ionsinadditiontoTi4+inLiMO2,bothofwhichwerefoundtofavorLi+-iontransferattheinterface.Asaresult,thecoatednanobeltsshowimprovedrate,cycling,andthermalcapabilitieswhenusedasthecathodeforLi-ionbattery.Tomeetmoredemandingrequirementsforstorageandutilizationofcleanenergy,Li-ionbatterieshavebeenurgedforlowercost,fastercharging/dischargingrate,highercapacity,longercyclinglife,andbetterenvironmentalbenignancy.1−6Layeredlithium-mixedtransitionmetaloxides,LiMO2(M=Ni,Co,Mn)havebeenregardedasprospectivealternativesforLiCoO2towardbetterLi-ionbatteries,duetotheiruniquepropertiesincludinghighenergydensity,goodcyclingstability,lowcost,andlowtoxicity.7−12Nevertheless,thereremainchallengesforLiMO2materials.First,theintrinsiclowLi+-ionconductivityofLiMO2preventstheimprovementofhighratecapability.Second,theinstabilityofde-lithiatedphaseofLiMO2inorganicelectrolytecausessafetyissuesandcapacityfadingduetothehighreactivityofCo4+andNi4+.CoatingwithelectrochemicallyinertoxidesandphosphateshasbeenanimportantandefficientapproachtoenhancetheelectrochemicalperformancesofLiMO2.13−17However,coat-ingmaterialsaregenerallyunfavorableforbothLi+-ionconductionofcathodematerialsandinterfacialchargetransferoftheelectrode,notonlybecausetheybehaveasinsulatorsforLi+-ionconduction,butalsobecausetheyincreaseLi+-diffusionlengthresultingindeteriorationofelectrochemicalperform-ance.18MonoclinicLi2TiO3,alayeredmaterialsimilartoLi2MnO3,hastheinterlamellar(002)d-spacingvalueof0.480nmwhichmatcheswellwith(003)d-spacingofLiMO2(0.468nm).Li2TiO3iselectrochemicallyinertinawidevoltagerangewithexcellentstructuralstabilityinorganicelectrolyte.19,20Moreimportantly,Li2TiO3hasathree-dimensionalpathforLi+-iondiffusion,inwhichLi+-ionmigrationcantakeplacein(003)planeandalongcdirection.21IthasbeenreportedthattheionicconductivityofLi2TiO3wouldincreasewhendopedwithaliovalentions.22,23Inthisregard,itispossiblethatathin,completeanddopedLi2TiO3coatinglayercanhelptoimprovetheratecapabilityaswellasthecyclingstabilityofLiMO2materials,whichwillbesignificanttotheperformanceimprovementofvariouscathodematerials.24−26Astothecoatingroute,traditionalapproachessuchasmechanicalmixing,sol−gel,andatomicdepositionmethodshavebeendeveloped.27−29However,thesemethodscannotestablishauniform,complete,robustandcontrollablecoatinglayeronthehostmaterials.Specifically,withmechanicalmethoditisdifficulttobuildacompletecoatinglayeronthehostmaterials,becausethecoatingparticlesdistributerandomlyonthesurfaceofthehostmaterials.Forsol−gelmethod,thethicknessofthecoatinglayerisdifficulttobeuniformduetoasimilarreason.Finally,forallthesemethodsthecoatinglayersareformedbypost-coatingroutesunderarelativelylowtemperature,resultingintheweakbondingbetweenthehostandthecoatinglayer.Towardbettersurface-modifiedcathodematerials,wepreparedaseriesofsurface-Li2TiO3-richLiMO2(M=Ni,Co,andMn)nanobelts(Ni:Co:Mn=8:1:1,6:2:2and4:3:3inmolarratio)withTi:(Ni+Co+Mn)=5:100inmolarratio.Weusedanovelandgeneralcoatingapproach,inwhicharobust,uniform,andcompletenanoscaleLi2TiO3layerdopedwithCo3+andNi2+ionshasbeenachieved.Thesyntheticapproachofthenanobeltsconsistsoftwosteps,inwhichTiO2-coatedMC2O4·xH2Onanobeltswerepreparedfirst,andthenthenanobeltswerelithiatedtogivethecoatedproduct(Scheme1).Mixedmetaloxalatenanobeltswerechosenastheprecursors,notonlyduetotheir1Dnanobeltstructures,butalsobecausetheirdehydrationreactioncanoccurataround150°C(seeTGAcurvesinFigureSI1a).TheuniformTiO2coatingofMC2O4·xH2Onanobeltswasbasedonasmartapproach,inwhichhighlyreactiveTi(OC4H9)4reactswithH2Omoleculesreleasedbythenanobeltsat150°CundersolvothermalReceived:September2,2012Published:January9,/JACS

Green ceramic machining: A top-down approach for the rapid fabrication of complex-shaped

ceramics

B. Sua, , , S. Dharaa, 1 and L. Wangb

aDepartment of Oral & Dental Science, University of Bristol, Bristol BS1 2LY, UK

bDepartment of Mechanical Engineering, University of Bristol, Bristol BS1 2LY, UK

Received 16 November 2007;

revised 8 February 2008;

accepted 15 February 2008.

Available online 15 April 2008.

Abstract

Green ceramic machining (GCM) has been investigated as an alternative method for the

mould-free fabrication of complex-shaped ceramics, where ceramics in ‘unsintered’ green state

are machined to complex-shaped via CAD/CAM technology. Recent advancement of CNC

machining technology makes GCM a potential alternative for the rapid fabrication of ceramics,

especially for some one-of-a-kind products. In this work, we investigated two processing routes to