简介:Theformationmechanismofmethane(CH4)duringcoalevolutionhasbeeninvestigatedbydensityfunctionaltheory(DFT)ofquantumchemistry.Thermogenicgas,whichisgeneratedduringthethermalevolutionofmediumrankcoal,isthemainsourceofcoalbedmethane(CBM).Ethylbenzene(A)and6,7-dimethyl-5,6,7,8-tetrahydro-1-hydroxynaphthalene(B)havebeenusedasmodelcompoundstostudythepyrolysismechanismofhighlyvolatilebituminouscoal(R),accordingtothesimilarityofbondordersandbondlengths.Allpossiblepathsaredesignedforeachmodel.ItcanbeconcludedthattheactivationenergiesforH-assistedpathsarelowerthanothersintheprocessofmethaneformation;anHradicalattackingonβ-CtoyieldCH4isthedominantpathfortheformationofCH4fromhighlyvolatilebituminouscoal.Inaddition,thecalculatedresultsalsorevealthatthepositionsonwhichHradicalattacksandtowhichintramolecularHmigrateshaveeffectsonmethylcleavage.
简介:AmodelofcrosslinkerunbindingisimplementedinahighlycoarsegrainedgranularmodelofF-actincytoskeleton.WeemploythisspecificgranularmodeltostudythemechanismsofthecompressiveresponsesofF-actinnetworks.ItisfoundthatthecompressiveresponseofF-actincytoskeletonhasdependencyonthestrainrate.TheevolutionofdeformationenergyinthenetworkindicatesthatcrosslinkerunbindingeventscaninducetheremodellingofF-actincytoskeletoninresponsetoexternalloadings.TheinternalstressinF-actincytoskeletoncanefficientlydissipatewiththehelpofcrosslinkerunbinding,whichcouldleadtothespontaneousrelaxationoflivingcells.