简介:SincethedesignstudiesofsolidtritiumbreederblanketmodelshavebeenperformedbyJapanandEUC,andtheirTBMdesignoptionsforITERhavebeenproposed.InordertodesignourTBMblanketoptionswithChineseresearchbasesandexperiences,wechoseliquidlithiumorlithium-leadasthetritiumbreedingmaterialsforourTBMblanketoptions.Howeverthethicknessoffirstwallisusuallyonlyafewcentimeters,
简介:Thispaperstudiesthedevelopmentonthefirstorderseacluttercrosssectionforbistatichighfrequencysurfacewaveradar(HFSWR).Basedonthereceivedfirstorderelectricfieldexpression,aclosed-formofcrosssectionsisderivedtoaccountforthecaseofreceivingantennaarraybeingmountedontheshipborneplatform.Theuniformlinearmotionandswaymotioncomponentsareassumedtoberesponsiblefortheobserveddifferencesincomparisonwiththebistaticfixedantennacase.Correspondingly,simulationsareconductedtostudytheseaclutterspectralcharacteristicsforthesetwocasesversusdifferentsystemparametersandseastateconditions.ItisshownnumericallythattheforwardmotioncomponentwillspreadtheBragglinesseverelyandtheinfluencetriggeredbytheswaymotioncanbeexplainedastheBesselfunctionmodulationoftheordinaryseaclutterspectra.TheobtainedresultshaveimportantimplicationsintheapplicationofshipborneHFSWRtechnologytooceanremotesensingandtargetdetection.
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简介:Inthispapertheexistenceresultsofpositiveω-periodicsolutionsareobtainedforsecondorderordinarydifferentialequation-u″(t)=f(t,u(t))(t∈R),andalsoforfirstorderordinarydifferentialequationu′(t)=f(t,u(t))(t∈R),wheref:R×R+→Risacontinuousfunctionwhichisω-periodicint.Thediscussionisbasedonthefixedpointindextheoryincones.
简介:Thefirstbirthmarksatransitionofawomanintomotherhood.Itcontributessubstantiallytooverallfertilityofeachindividualwoman.Theageatwhichchildbearingbeginsinfluencesthenumberofchildrenawomanbearsthroughoutherwholereproductivelifespan.Thus,themother’sageatfirstbirthinfluencesthetotalnumberofbirthsthatshemighthaveinherlife,whichimpactsthesize,composition,andfuturegrowthofthepopulation.Child-bearingatveryyoungagesiscommonamongthepoorinBangladesh.Theobjectiveofthepresentstudyistoexaminethefactorsassociatedwithageatfirstbirthamongslumdwellersoffiveselectedslums(locally,colony)inSylhetcitycorporationarea,Bangladesh.Thedataofthisstudywascollectedfrom520womenaged14-50years.Thestudyfoundthatalmost93%ofwomenweremarriedbytheagesof18yearsandabout56%ofthewomenhavehadtheirfirstchildbytheageof18years.TheOrdinaryLeastSquares(OLS)regressionmodelwasusedtoanalyzethefactorscorrelatedwithwomen’sageatfirstbirth.TheregressionmodelissignificantwithanF-valueof49.48andcanexplain40.4%ofthevariationinthedependentvariableasitisindicatedbytheR-square.
简介:ThisReviewfocusesonopticaltransmissionfibersandthehigh-capacitysystemsoperatingthereon.Itattemptstocombinekeylessonslearnedfromthe50-yearhistoryoflow-lossopticalfiberswithviewsonfuturefiberandsystemsrequirements,discussinglikelyevolutionpathsandpotentialpitfallsinresolvingtheopticalnetworkcapacitycrunch.
简介:ChinaTertiaryIndustryFirstNationalCensus:SelectedSummaryStatistics¥//Inlate1994,Chinacompleteditsfirstnationalcensusofitstert...
简介:WhatisPADIS-INT?PDIS-INTisthesoftwareuniversallyappliedinpopulationprojection,whichisdevelopedbyCPDRCwiththeguidanceandsupportofDirectorofPopulationDivision/DESA,UnitedNations,basedontheadvancedtechnologiesusedintheoriginalversionofPADIS.Applyingtheadvancedcom-putertechnologiesinpopulationprojection,thesoftwarehasfollowingthreefeatures:1.theJAVAvirtualmachineassurestheirrelevancebetween
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简介:Naturalgashydrates(NGH)isoneofkeyfuturecleanenergyresources.Itsindustrializeddevelopmentwillhelpremitthehugedemandofglobalnaturalgas,relievetheincreasingpressureoftheenvironment,andplayavitalroleinthegreensustainablegrowthofhumansocieties.Basedonnearlytwodecades'studyingonthereservoircharacteristicsintheSouthChinaSea(SCS)andtheknowledgeofreservoirsystem,theChinaGeologicalSurvey(CGS)conductedthefirstproductiontestonanoptimaltargetselectedinShenhuareaSCSin2017.Guidedbythe"three-phasecontrol"exploitationtheorywhichfocusedonformationstabilization,technologiessuchasformationfluidextraction,welldrillingandcompleting,reservoirstimulating,sandcontrolling,environmentalmonitoring,monitoringandpreventingofsecondaryformationofhydrateswereapplied.Thetestlastedfor60daysfromMay10^thwhenstartingtopump,droppressureandignitetowellkillingonJuly9^th,withgasproductionof3.09×10^5m^3intotal,whichisaworldrecordwiththelongestcontinuousdurationofgasproductionandmaximalgasyield.ThissuccessfultestbringsasignificantbreakthroughonsafetycontrolofNGHproduction.