简介：Fracturetoughnessisoneofthecrucialmechanicalpropertiesofbrittlematerialssuchasglassesandceramicswhichdemonstratecatastrophicfailuremodes.Conventionalstandardizedtestingmethodsadoptedforfracturetoughnessdeterminationrequirelargespecimenstosatisfytheplanestraincondition.Asforsmallspecimens,indentationisapopular,sometimesexclusivetestingmodetodeterminefracturetoughnessforitcanbeperformedonasmallflatareaofthespecimensurface.Thisreviewfocusesonthedevelopmentofindentationfracturetheoriesandtherepresentativetestingmethods.Crackingpatterndependentonindentergeometryandmaterialpropertyplaysanimportantroleinmodeling,andisthemainreasonforthediversityofindentationfracturetheoriesandtestingmethods.Alongwiththesimplicityofspecimenrequirementisthecomplexityofmodelingandanalysiswhichaccountsforthesemi-empiricalfeaturesofindentationfracturetests.Someunresolvedissuesshapingthegapbetweenindentationfracturetestsandstandardizationarealsodiscussed.更多还原

简介：Usingultrasonicguidedwavestoassesslongbonefracturesandfracturehealinghasbecomeapromisingdiagnosticissue.Butthemultimodeoverlapoftheguidedwaveschallengesthequantitativeevaluationandclinicalapplication.Inthepreformedstudy,inordertosimplifythesignalinterpretation,thelow-frequencysinusoidialsignalswereusedtoonlyexciteS0andA0modesinfracturedlongbones.TheamplitudesofS0andA0modeswerenumericallyanalyzedwithvariationincrackwidthandfractureangle.Numericalsimulation,basedonthetwo-dimensionfinite-differencetime-domain(2D-FDTD)revealsthatbothS0andA0amplitudesdecreasewiththefracturewidening.However,theincreaseinfractureanglegraduallyenhancestheA0amplitude,whilewithrespecttotheS0mode,itsamplitudeshowsanon-monotonictrendtothevariationinfractureanglewithaturningpointaround45°.TheamplituderatiobetweenS0andA0canreflectthevariationsincrackwidthandfractureangles.ThesimulationillustratesthatultrasonicguidedS0andA0modesaresensitivetothedegreeofbothverticalandobliquefracturesinthelongcorticalbone.Thesefindingsmaybehelpfulforfracturesdiagnosisandhealingevaluationofthelongbone.

简介：这研究试图调查trabecular的地区性的变化，以及决定在trabecular之间的关系词法参数和大腿骨的头的机械参数词法、机械的参数。从有折断的近似腿节的病人的七个大腿骨的头用一个micro-CT系统被扫描。每个大腿骨的头根据trabecular取向被划分成12个分区。一\(125\，\hbox{公里}^{3}\)trabecular立方的模型从每个分区被重建。81个trabecular模型的一个总数被重建，除了从在外科期间的二个大腿骨的头的三个破坏分区。Trabecular词法参数，即trabecular分离(Tb.Sp)，trabecular厚度(Tb.Th)，特定的骨头表面(BS/BV)，骨头体积部分(BV/TV)，结构的模型索引(SMI)，和anisotropy(DA)的度被测量。微有限的元素分析被执行让每个立方体获得明显的幼仔模量，织物水平von协定在1%下面强调分发沿着三个直角的方向的压缩紧张分别地。结果在词法参数揭示了重要地区性的变化(\(P)。沿着trabecular取向的幼仔moduli比沿着另外的二个方向的那些显著地高。一般来说，trabecular在中间的区域的机械性质是比在侧面的区域的那些低的。沿着trabecular取向的Trabecular机械参数显著地与BS/BV，BV/TV，Tb.Th，和DA被相关。在这研究，在有近似腿节骨折的病人的大腿骨的头的微结构特征和机械性质的地区性的变化彻底地在组织水平被调查。这研究的结果将帮助阐明为减少破裂风险和发展中的治疗策略为的大腿骨的头骨折的机制老。

简介：Renalcellcarcinoma(RCC)accountsforapproximately3%ofallcancercases.RCCsusuallymetastasizetothelungs,bones,liver,orbrain.Only<1%ofpatientswithbonemetastasesmanifestedclavicularRCCmetastases.Thus,clavicularmetastasisastheinitialpresentationofRCCisextremelyrare.WereportapatientwithRCCmetastasistotheleftclavicle,whichwasfirstpresentedwithpaincausedbyapathologicalfracture.Magneticresonanceimagerevealedarenaltumor,andtechnetium-99m–methylenediphosphonatebonescintigraphyshowedmultipleosseousmetastases.Thepatienteventuallyunderwentsurgerytoremovethelateralendoftheleftclavicleandrightkidney.Histopathologyrevealedrenaltumorandclearcellcarcinomaintheclavicle.Finally,wereview17casesofclavicularmetastasesoriginatingfromdifferentmalignancies.