简介:针对四旋翼无人机鲁棒自适应飞行问题,提出了一种基于指数收敛的控制方法。考虑到四旋翼系统的欠驱动、强耦合等非线性特性,采用线性化反馈控制策略实现对其轨迹追踪飞行能力的基本控制;针对线性化反馈控制易受系统内外部未知干扰等影响,采用基于指数收敛干扰观测器组合控制设计,实现四旋翼飞行的鲁棒与自适应控制;线性反馈及状态观测器控制系统基于指数收敛稳定。进行了仿真分析,结果表明,干扰观测器对四旋翼系统中存在的未知干扰具有很好的估计能力,所设计的基于指数收敛控制系统,结构简单,且具有较强的干扰抑制能力和较高的系统稳定性,满足四旋翼无人机的鲁棒及自适应飞行能力要求。
简介:采用EDTA络合滴定法测定选铁尾矿中的氟化钙含量。选用稀乙酸浸取试样中的碳酸钙,分离过滤氟化钙,用锆-二甲酚橙褪色分光光度法测定浸取液中的氟含量,折算为在稀乙酸中微溶的氟化钙的量;同时沉淀部分用氯化铝溶液在沸水浴中溶解浸取氟化钙,以三乙醇胺掩蔽干扰离子,在KOH介质中,以钙指示剂为指示剂,用EDTA标准滴定溶液测定沉淀中氟化钙的量,两者之和为试样中氟化钙的含量。用此法对试样进行11次平行测定,相对标准偏差(RSD)小于1.0%。在选铁尾矿试样中加入萤石标准物质进行加标回收实验,加标回收率在99%-102%。方法流程短,操作简单。精密度和加标回收率均能满足要求。
简介:Vanadiumalloys(V-Cr-Tiseries)areimportantcandidatematerialsforblanketcomponentsoffusionreactorsduetotheirlowactivationandhighstrengthatelevatedtemperatures.Low-temperatureirradiationembrittlementdeterminestheoperationtemperaturelimitofVanadiumalloysfortheapplicationtostructuralmaterialsoffusionreactorsirradiationresponseofvanadiumalloysneedstobeclarifiedfortheirapplication.Inthepresentstudy,specimensoftwoalloys(V-4Cr-4TiandV-5Cr-5Ti)wereirradiatedwithenergeticHeionsandheavyionstounderstandhardeningofthealloysduetoheliumaccumulationandcascadedamageproduction.
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简介:ThecokedepositiononHZSM-5/SAPO-34compositecatalystshasbeenstudiedintheconversionofethanoltopropylene.TheHZSM-5/SAPO-34compositecatalystsweresynthesizedbyhydrothermalmethod(ZS-HS)andfullyblending(ZS-MM).TheusedcatalystswerecharacterizedbyXRD,N2adsorption–desorption,TGA,TPO,elementalanalysis,FTIRandXPS.ThecokingkineticsonbothZS-HSandZS-MMhasbeeninvestigatedandtheircokingrateequationswereobtained.TheusedZS-MMcatalysthadhigheramountofcokeandlowernC:nHthantheusedZS-HS.90%ofthecokewasdepositedinthemicroporesofZS-HS,whilealmost45%ofthecokelocatedinthemicroporesofZS-MM.ThecokedepositedonZS-HScatalystwasmainlygraphite-likecarbonspecies,whereasdehydrogenatedcokespecieswasthemajoronZS-MM.ThecokingactivationenergyofZS-MMwaslowerthanthatofZS-HS,andthecokingrateonZS-MMwasfasterthanonZS-HS.Inaddition,theregenerationofZS-MMcatalystshowedthatithadagoodhydrothermalstability.Thedifferencesoncokingbehaviorsonthetwocatalystswereduetotheirdifferentacidicpropertiesandtextures.
简介:Two-dimensionalatomic-layeredmaterialisarecentresearchfocus,andsinglelayerTa2O5usedasgatedielectricinfield-effecttransistorsisobtainedviaassembliesofTa2O5nanosheets.However,theelectricalperformanceisseriouslyaffectedbyelectronicdefectsexistinginTa2O5.Therefore,spectroscopicellipsometryisusedtocalculatethetransitionenergiesandcorrespondingprobabilitiesfortwodifferentchargedoxygenvacancies,whoseexistenceisrevealedbyx-rayphotoelectronspectroscopyanalysis.SpectroscopicellipsometryfittingalsocalculatesthethicknessofsinglelayerTa2O5,exhibitinggoodagreementwithatomicforcemicroscopymeasurement.NondestructiveandnoncontactspectroscopicellipsometryisappropriatefordetectingtheelectricaldefectslevelofsinglelayerTa2O5.
简介:Inthiswork,aseriesofMIL-101-SO3H(x)polymericmaterialswerepreparedandfurtherusedforthefirsttimeasefficientheterogeneouscatalystsfortheconversionoffructose-basedcarbohydratesinto5-ethoxymethylfurfural(EMF)inarenewablemixedsolventsystemconsistingofethanolandtetrahydrofuran(THF).Theinfluenceof–SO3HcontentontheacidityaswellasonthecatalyticactivityoftheporouscoordinationpolymersinEMFproductionwasalsostudied.HighEMFyieldsof67.7%and54.2%couldbesuccessivelyobtainedfromfructoseandinulininthepresenceofMIL-101-SO3H(100)at130°Cfor15h.Thecatalystcouldbereusedforfivetimeswithoutsignificantlossofitsactivityandtherecoveryprocesswasfacileandsimple.Thisworkprovidesanewplatformbyapplicationofporouscoordinationpolymers(PCPs)fortheproductionofthepotentialliquidfuelmoleculeEMFfrombiomassinasustainablesolventsystem.
简介:针对加速器驱动次临界系统(acceleratordrivensubcriticalsystem,ADS)堆芯内快中子份额大、多核素共振现象较强、液态铅锯(Pb-Bi)合金冷却剂中子增殖的特点,开发了一套用于ADS燃耗分析的MCNP多群数据库制作程序。基于最新的ENDF/B-1.1和JENDL40评价库,制作了30群阶数据库,对影响MCNP多群计算精度的能群结构、散射角分布、(n,2n)和(n,3n)反应截面进行了敏感性研究,并利用快谱基准装置和ADS堆芯模型进行了验证。结果表明,制作的多群数据库达到了较高的计算精度,计算效率较连续能量点截面MCNP程序提高1.3倍。
简介:AseriesofnovelN-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl)amidesderivativesweredesignedandsynthesized.Theirstructureswereconfirmedby1HNMR,13CNMRandHRMS.Alltitlecompoundswereevaluatedfortheirherbicidalandantifungalactivities.Preliminarybioassayresultsindicatedthatthetitlecompoundsshowedgoodtomoderateherbicidalactivityat1000mg/L.Compound6qpresentedthebestactivityagainstDigitariasanguinalis(L)Scop.,AmaranthusretroflexusL.andArabidopsisthalianawithaninhibitiondegreeoffive.Compound6dalsoshowedaninhibitiondegreeoffiveagainstD.sanguinalis.Inaddition,at50mg/L,mostcompoundsexhibitedgoodinvitroantifungalactivityagainstSclerotiniasclerotiorum,withcompound6cshowingover90%antifungalactivityagainstS.sclerotiorumandPelliculariasasakii.
简介:Themassesofneutron-defcientnuclidesplayacriticalroleinthecalculationofastrophysicalrapidproton-captureprocesses[1].Neutron-defcientnuclideswithmassnumber∧around80arethelastsetofnuclideswithunknownmassesonthepathwayofvp-process[2].Themassmeasurementofnuclideswouldbeveryuseful.In2016,massesofneutron-defcientnuclides79Y,81Zr,82Zr,83Nband84Nbnucleiwerepreciselymeasureddirectlybytheexperimentalstorage-ringCSReatLanzhou.
简介:AnewlayeredCu-basedoxychalcogenideBa3Fe2O5Cu2S2hasbeensynthesizedanditsmagneticandelectronicpropertieswererevealed.Ba3Fe2O5Cu2S2isbuiltupbyalternativelystacking[Cu2S2]2-layersandironperovskiteoxide[(FeO2)(BaO)(FeO2)]2-layersalongthecaxisthatareseparatedbybariumionswithFe3+fivefoldcoordinatedbyasquare-pyramidalarrangementofoxygen.Fromthebondvalencearguments,weinferredthatinlayeredCuCh-based(Ch=S,Se,Te)compoundsthe+3cationinperovskiteoxidesheetprefersasquarepyramidalsite,whilethelowervalencecationprefersthesquareplanarsites.Thestudiesonsusceptibility,transport,andopticalreflectivityindicatethatBa3Fe2O5Cu2S2isanantiferromagneticsemiconductorwithaNe′eltemperatureof121Kandanopticalbandgapof1.03eV.Themeasurementofheatcapacityfrom10Ktoroomtemperatureshowsnoanomalyat121K.TheDebyetemperatureisdeterminedtobe113K.TheoreticalcalculationsindicatethattheconductionbandminimumispredominantlycontributedbyO2pand3dstatesofFeionsthatantiferromagneticallyarrangedinFeO2layers.TheFe3dstatesarelocatedatlowerenergyandresultinanarrowbandgapincomparisonwiththatoftheisostructuralSr3Sc2O5Cu2S2.