简介：Thisfirstessayisaboutapendingmarriagebetweenbiologyandsomeofthetechnologiesofengineering.Itisastoryofalong-standingflirtationthathasbeenconsummatedanumberoftimes,butneverproperlysolemnised,despiterepeatedattempts,andnooneisquitesurehowmanyoftheoffspring,ifany,havebeenviable.Whethertheunionwillbeblessedinthenearfutureisanyone'sguess.Inthehopeofhelpingthemarriageonitsway,Istartwithfourluckythingsthebridehastowearattheweddingforthemarriagetosucceed,atleastinoneofthemorerecentWesterntraditions.

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简介：1Chemistryandsynthesis1.1ProductionandcontrolofmaterialsThesedaystherecanbefewpeoplewhodonotknowthatproteinsaredefinedbyDNA.DNAismadeoftwostrands,eachofwhichhasalongit,likeastringoffairylights,sidebranchesthatmeetbetweenthestrandsandholdthemtogether.

简介：1TechnologyofnaturalmaterialsEarlymanusedconvenientlyshapedstonesastools."Workshop"areashavebeenfoundwithlargenumbersofstones,someshowingsignsofbeingworked[1].However,organicmaterialslikewoodwilldecayundernormalwetconditionsinthepresenceofoxygen,sowewon'tfindthesamesortofevidenceforwoodentools.Itissafetoassumethatearlymanusedsticksasprobesandclubs,andmaybeevenformakingsomesortofnestlikeprotectionagainsttheelementsandpredators,sinceweseechimpanzeesandotheranimalsdoingthissortofthing.Sowood,andalmostcertainlyotherplantmaterialssuchasfibrousleaves,andboneandothermaterialsgleanedfromdeadanimals,wouldbeusedfromtheearliesttimes.WeneedtoknowthisinordertoestablishtheideathatMancanbeexpectedtohavealonghistoryoftheuseandmanipulationofnaturalmaterials.Thisneedsskillsinchoosingmaterialsforcertainusesonthebasisoftheirmechanicalproperties,whetherthosepropertiesaretodowiththeeaseofshapingthematerialortheeffectivenessofthatmaterialinuse.Occasionallythematerialwaschosensimplybecauseitwasreadilyavailable.Ifwefindthataparticularmaterialwasalwaysusedforacertainjob,it'sreasonabletodeducethatManwasexertingmaterialsselectioncriteriathroughexperience.

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简介：MedicalforgedCoCrMoalloywastreatedbyplasmanitridingprocess.Themicrostructureswerecharacterizedby3Dprofiler,SEMandXRD.Thetribologicalpropertieswereinvestigatedunderlubricationof25%bovineserumsolution.Resultsshowthatplasmanitridingisapromisingprocesstoproducethick,hard,andmorewearresistantlayersonthesurfaceofCoCrMoalloy.AllnitridedsamplesshowedanimportantincreaseinthesurfacehardnessduetotheformationofharderCrNandCr2Nphaseswithcompactnano-crystallinestructures.ThetypicalhardnessvaluesofHV0.05increasedalmosttwotimesthanuntreatedone.Underbovineserumlubrication,atlownitridingtemperaturetheCoefficientofFriction（COF）ofnitridedsamplewaslowerthanthatofuntreatedsample,butathighnitridingtemperaturetheCOFwasalmostthesameastheuntreatedone.Comparedwiththeuntreatedsample,thenitridedsamplesshowedlowerwearratesandhigherwearresistanceunderdifferentnitridingtemperatures.TheadhesivewearisthemainmechanismforuntreatedCoCrMoalloyandthewearmechanismsofnitridedonesarethefatiguewearandslightadhesivewear.ItisconcludedthattheimprovementofwearresistanceisascribedtothehardnitrideformationofCrNandCr2Nphasesatthenitridedsurfaces.

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