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简介：Ｐｏｐｕｌａｔｉｏｎ：ＫｅｙｔｏＢａｌａｎｃｅｄＦｏｏｄＳｕｐｐｌｙＦｒｏｍ１９４９ｔｏ１９７８，ｇｒａｉｎｏｕｔｐｕｔｉｎｃｒｅａｓｅｄｆｒｏｍ１１３ｍｉｌｉｏｎｔｏ３０４ｍｉｌｉｏｎｔｏｎｓ，ａｎｉｎｃｒｅａｓｅｏｆ１６９．６％，ｗｈｉｌｅｔｈｅ...

简介：ＩｎｔｒｏｄｕｃｔｉｏｎＤｉｇｉｔａｌｓｔｒｏｎｇｇｒｏｕｎｄａｃｅｌｅｒａｔｉｏｎｏｂｓｅｒｖａｔｉｏｎｉｎｓｔｒｕｍｅｎｔ，ｓｕｃｈａｓＰＤＲ１，ＳＳＡ１ａｎｄＳＳＲ１ｐｒｏｄｕｃｅｄｂｙＫｉｎｅｍｅｔｒｉｃｓＩｎｃ．，ＵＳＡａｎｄＳＣＱ?..

简介：Thispaperexaminestheapproachusedbymiddleschoolteacherstoteachingtextsandarguesagainstthetraditionalpracticeofexploitingtextsjusttoteachgrammarandvocabulary.Amorebalancedapproachispresented,involvingallfour-languageskills,concentratingonoutputaswellasinput,andtrainingstu-dentstoextractrelevantinformationfromtexts,makingthemmoreefficientreaders.

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简介：Inthisletter,atheoreticalmodelofradiation-balanceddoublecladfiberlaserispresented.ThecharacteristicofthelaserwithYbdopeddoublecladfiberisanalyzednumerically.Itisconcludedthathighoutputlaserpowercanbeobtainedbyselectingoutputcouplingmirrorwithlowerreflectivity,improvingYbdopedconcentrationandchoosingfiberlength.Thisresultcanhelpustodesignradiationbalancedfiberlaser.

简介：Stabilityanddynamiccharacteristicsofaballbearing-rotorsystemareinvestigatedundertheeffectoftheclearanceintheballbearing.DifferentclearancevaluesareassumedtocalculatethenonlinearstabilityofperiodicsolutionwiththeaidoftheFloquettheory.Bifurcationandchaosbehaviorareanalyzedwithvariationoftheclearanceandrotationalspeed.Itisfoundthattherearethreeroutestounstableperiodicsolution.Theperiod-doublingbifurcationandthesecondaryHopfbifurcationaretwousualroutestoinstability.Thethirdrouteistheboundarycrisis,achaoticattractoroccurssuddenlyasthespeedpassesthroughitscriticalvalue.Atlast,theinstablerangesfordifferentinternalclearancevaluesaredescribed.Itisusefultoinvestigatethestabilitypropertyofballbearingrotorsystem.

简介：Thedynamicinput-outputsystemiswellknownineconomictheoryandpractice.Inthispapertheasymptoticstabilityandbalancedgrowthsolutionofthedynamicinput-outputsystemareconsidered.Underthreenaturalassumptions,weobtainfourtheoremsaboutasymptoticstabilityandbalancedgrowthsolutionofthedynamicinput-outputsystemandbringtogetherinaunifiedmannersomecontributionsscatteredintheliterature.

简介：Thenecessaryandsufficientconditionsfortheexistenceofsimpleincompleteblockdesign(v,w;4,2)-IPBDsaredetermined.Asaconsequence,thenecessaryandsufficientconditionsfortheembeddingsofsimpletwo-foldbalancedincompleteblockdesignswithblocksize4arealsodetermined.

简介：Astudyonbalancedfertilizationwasconductedbymeansoflong-termfieldexperiments,andaconve-nienttableforbalancedfertilizationwascompiled.Theexperimentalresultsabouttheeffectoffertilizationonwateruseefficiencyofuplandwheatshowedthattheinputofinorganicfertilizershouldbereducedindryyears.

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