为你找到 1000 条关于 一、单项选择题(每题2分,共60分) 的结果
40.S7-200PLC中,欲在M区偏移地址30处存放一个字节的变量,该变量的地址表示成MW30。()
1、新车交付前的检查中发动机的起动检查,蓄电池电压应不高于12V。
三、判断题2、场强的方向即为电势的降落方向。()
三、判断题2、电场中任意两相邻等势面之间的电势差不一定相等。()
三、判断题2、有限带电体一般以无穷远为电势零点,常选择地球电势为零。()
PartⅡDothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?(每题2分,共计14分)Inboxes16-22onyourAnswerSheet,writeTRUEifthestatementagreeswiththeinformationFALSEifthestatementcontradictstheinformationNOTGIVENifthereisnoinformationonthisinthepassageText4:AirTrafficControlintheUSAAnaccidentthatoccurredintheskiesovertheGrandCanyonin1956resultedintheestablishmentoftheFederalAviationAdministration(FAA)toregulateandoverseetheoperationofaircraftintheskiesovertheUnitedStates,whichwerebecomingquitecongested.TheresultingstructureofairtrafficcontrolhasgreatlyincreasedthesafetyofflightintheUnitedStates,andsimilarairtrafficcontrolproceduresarealsoinplaceovermuchoftherestoftheworld.Rudimentaryairtrafficcontrol(ATC)existedwellbeforetheGrandCanyondisaster.Asearlyasthe1920s,theearliestairtrafficcontrollersmanuallyguidedaircraftinthevicinityoftheairports,usinglightsandflags,whilebeaconsandflashinglightswereplacedalongcross-countryroutestoestablishtheearliestairways.However,thispurelyvisualsystemwasuselessinbadweather,and,bythe1930s,radiocommunicationwascomingintouseforATC.Thefirstregiontohavesomethingapproximatingtoday'sATCwasNewYorkCity,withothermajormetropolitanareasfollowingsoonafter.Inthe1940s,ATCcentrescouldanddidtakeadvantageofthenewlydevelopedradarandimprovedradiocommunicationbroughtaboutbytheSecondWorldWar,butthesystemremainedrudimentary.ItwasonlyafterthecreationoftheFAAthatfull-scaleregulationofAmerica'sairspacetookplace,andthiswasfortuitous,fortheadventofthejetenginesuddenlyresultedinalargenumberofveryfastplanes,reducingpilots'marginoferrorandpracticallydemandingsomesetofrulestokeepeveryonewellseparatedandoperatingsafelyintheair.ManypeoplethinkthatATCconsistsofarowofcontrollerssittinginfrontoftheirradarscreensatthenation'sairports,tellingarrivinganddepartingtrafficwhattodo.Thisisaveryincompletepartofthepicture.TheFAArealisedthattheairspaceovertheUnitedStateswouldatanytimehavemanydifferentkindsofplanes,flyingformanydifferentpurposes,inavarietyofweatherconditions,andthesamekindofstructurewasneededtoaccommodateallofthem.Tomeetthischallenge,thefollowingelementswereputintoeffect.First,ATCextendsovervirtuallytheentireUnitedStates.Ingeneral,from365mabovethegroundandhigher,theentirecountryisblanketedbycontrolledairspace.Incertainareas,mainlynearairports,controlledairspaceextendsdownto215mabovetheground,and,intheimmediatevicinityofanairport,allthewaydowntothesurface.ControlledairspaceisthatairspaceinwhichFAAregulationsapply.Elsewhere,inuncontrolledairspace,pilotsareboundbyfewerregulations.Inthisway,therecreationalpilotwhosimplywishestogoflyingforawhilewithoutalltherestrictionsimposedbytheFAAhasonlytostayinuncontrolledairspace,below365m,whilethepilotwhodoeswanttheprotectionaffordedbyATCcaneasilyenterthecontrolledairspace.TheFAAthenrecognisedtwotypesofoperatingenvironments.Ingoodmeteorologicalconditions,flyingwouldbepermittedunderVisualFlightRules(VFR,视觉飞行规则),whichsuggestsastrongrelianceonvisualcuestomaintainanacceptablelevelofsafety.PoorvisibilitynecessitatedasetofInstrumentalFlightRules(IFR,仪表飞行规则),underwhichthepilotreliedonaltitudeandnavigationalinformationprovidedbytheplane'sinstrumentpaneltoflysafely.Onaclearday,apilotincontrolledairspacecanchooseaVFRorIFRflightplan,andtheFAAregulationsweredevisedinawaywhichaccommodatesbothVFRandIFRoperationsinthesameairspace.However,apilotcanonlychoosetoflyIFRiftheypossessaninstrumentratingwhichisaboveandbeyondthebasicpilot'slicensethatmustalsobeheld.onaltitudeandnavigationalinformationprovidedbytheplane'sinstrumentpaneltoflysafely.Onaclearday,apilotincontrolledairspacecanchooseaVFRorIFRflightplan,andtheFAAregulationsweredevisedinawaywhichaccommodatesbothVFRandIFRoperationsinthesameairspace.However,apilotcanonlychoosetoflyIFRiftheypossessaninstrumentratingwhichisaboveandbeyondthebasicpilot'slicensethatmustalsobeheld.Controlledairspaceisdividedintoseveraldifferenttypes,designatedbylettersofthealphabet.UncontrolledairspaceisdesignatedClassF,whilecontrolledairspacebelow5,490mabovesealevelandnotinthevicinityofanairportisClassE.Allairspaceabove5,490misdesignatedClassA.ThereasonforthedivisionofClassEandClassAairspacestemsfromthetypeofplanesoperatinginthem.Generally,ClassEairspaceiswhereonefindsgeneralaviationaircraft(fewofwhichcanclimbabove5,490manyway),andcommercialturbopropaircraft.Above5,490mistherealmoftheheavyjets,sincejetenginesoperatemoreefficientlyathigheraltitudes.ThedifferencebetweenClassEandAairspaceisthatinClassA,alloperationsareIFR,andpilotsmustbeinstrument-rated,thatis,skilledandlicensedinaircraftinstrumentation.ThisisbecauseATCcontroloftheentirespaceisessential.Threeothertypesofairspace,ClassesD,CandB,governthevicinityofairports.Thesecorrespondroughlytosmallmunicipal,medium-sizedmetropolitanandmajormetropolitanairportsrespectively,andencompassanincreasinglyrigoroussetofregulations.Forexample,allaVFRpilothastodotoenterClassCairspaceisestablishtwo-wayradiocontactwithATC.NoexplicitpermissionfromATCtoenterisneeded,althoughthepilotmustcontinuetoobeyallregulationsgoverningVFRflight.ToenterClassBairspace,suchasonapproachtoamajormetropolitanairport,anexplicitATCclearance(飞机起降的许可)isrequired.Theprivatepilotwhocruiseswithoutpermissionintothisairspaceriskslosingtheirlicense.16.TheFAAwascreatedasaresultoftheintroductionofthejetengine.
三、判断题2、静电场中的电场线形成闭合曲线。()
二、单项选择题1、下列变量中属于离散型变量的有()
三、判断题2、运动的电荷可以产生磁效应。()
三、判断题2、电场中任意两相邻等势面之间的电势差相等。()
1、独立电源都是可以短路
三、判断题(请把正确的答案填入相应的答题框内,共10小题,每小题1分,共10分)1.网络支付结算的成本比传统支付方式要高。()
9.若年利率为12%,每季复利一次,则每年期利率实际利率等于()。
1.许可制需要有关主管机构的批准,而注册制的实质是,只要有关机构符合法定的条件,经过一定的注册程序即可从事证券业务,而无须主管机构的特别批准。
正确
13.投资项目的净现金流量的符号从负到正只变化一次,而且净现金流量的总和大于零,则其内部收益率有()