简介：Inthispaper,nonnegativesolutionsforthedegenerateellipticsystemsareconsidered.First,nonnegativesolutionsforscalarequationwithspatialdiscontinuitiesarestudied.Thenthemethoddevelopedforscalarequationisappliedtostudyellipticsystems.Atlast,theexistencecriteriaofnonnegativesolutionsofellipticsystemsaregiven.
简介：Inthispaper,weinvestigatethestationaryprobabilitydistributionandmeanfirstpassagetimeinavegetationecologicalsystem,whichisdrivenbycross-correlationbetweenintrinsicandextrinsiccolorednoisesaswellasthenonzerocross-correlationinbetween.Theimpactsoftheself-correlationtimeτ1andτ2,thecross-correlationtimeτ3andintensitykonthestationaryprobabilitydistributionandmeanfirstpassagetimearediscussed,respectively.Ourmainresultsshowthat:(i)theself-correlationtimeτ1caninduceregimeshiftsfromthedesertstatetothesustainablevegetationstate,whiletheself-correlationtimeτ2,cross-correlationtimeτ3andintensitykcaninduceregimeshiftsfromthesustainablevegetationstatetothedesertstate;and(ii)theself-correlationtimeτ1orτ2canenhancethestabilityofthesustainablevegetationbiomass,whilethecross-correlationtimeτ3orstrengthkweakensthestabilityofthesustainablevegetationbiomass.
简介：Metalworkingfluidsaretheportionofabigfamilyoflubricants.Metalworkingfluidshavebeenwidelyusedforcuttingthemetalandthemostcommunalcategoryofthesesfluidsarewatermixingfluids.Inthisarticle,themethodsoflubricationusingduringvariousoperationsofmachiningispresentingandalsorepresentthevariousbenefitsofthesefunctionalfluidsinmachiningwithrespecttosurfacefinish,cuttingforce,temperatureatthezoneofcutting.Thedisadvantagesandperformanceofvariousmethodsarediscussedintermsofoutputvariablesandparametersofmachining.Fromthevariousliteratures,itcanbereportedthatfluidsofcuttingwhicharemadebytheoilofvegetable,couldbeeco-friendlyinmachiningmodewithsameinperformanceachievedafterusingthemetalworkingfluidwhicharebasedonmineraloil.Thevariouslubricationmethodsaregoingtobefinishedbecauseoflesscoolingrate.
简介：Thispaperinvestigatespersistenceoftransientdynamicsdependingonparametersinspatiallycoupledecologicalsystems.WeemphasisthatthepersistencetimecanbeobtainedbypopulationsofspeciesorLyapunovexponentsoftransientdynamics.Itisfoundthatextremesensitivedependenceofpersistenceonparametersoccurscommonlyinecologicalmodels.Anon-zerouncertaintyexponentisusedtocharacterizethehighsensitivityinareasonableparameterregion.Theresultofasmalluncertaintyexpone...
简介：Abstract.OnthebasisofclassificationofgeographicalpropertiesarollingdevelopmentgoalprogrammingmodelisformulatedincorrespondencewiththeecopatterngroupinFour-LakeArea.Inthismodel,thecontrolofschistosomiasisandstrengthen-Lugofthedrainage-storagefunctionarebothregardedasecologicalmeasuresduringtheprocessofmulti-year(r0)ecologicaleconomicrollingdevelopmenttomaketheecoagrlculturalsysteminthisareaintoastablyoperating,ordered,andgoodcyclicsystemunderthesupportofsomecontrollablefactors.
简介：Ithasbeenreportedthattheminimalspatiallyextendedphytoplankton-zooplanktonsystemexhibitsbothtemporalregular/chaoticbehaviour,andspatiotemporalchaosinapatchyenvironment.Asafurtherinvestigationbymeansofcomputersimulationsandtheoreticalanalysis,inthispaperweobservethatthespiralwavesmayexistandthespatiotemporalchaosemergewhentheparametersarewithinthemixedTuring-Hopfbifurcationregion,whicharisesfromthefar-fieldbreakupofthespiralwavesoveralargerangeofdiffusioncoefficientsofphytoplanktonandzooplankton.Moreover,thespatiotemporalchaosarisingfromthefar-fieldbreakupofspiralwavesdoesnotgraduallyinvadethewholespaceofthatregion.Ourresultsareconfirmedbynonlinearbifurcationofwavetrains.Wealsodiscussecologicalimplicationsofthesespatiallystructuredpatterns.
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