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16 个结果
  • 简介:NanostructuredtitaniahavebeenintensivelyinvestigatedasanodematerialsofLi-ionbatteriesfortheirexcellenthighrateperformance.ThesizeeffectsofTiO2polymorphs(mainlyrutile,anataseandTiO2-B)ontheirelectrochemicalperformanceandthelatesteffortsinnanoengineeringtitaniaanodesthroughenhancingtheirionicorelectronictransportationorbotharereviewedinthiswork.Wesupposethatmicron-orsubmicronsizedporousstructuresassembledbyTiO2nanoparticles,nanowires/nanotubesornanosheetswithahighpercentageofexposinghighreactivefacetstogetherwithaconductivepercolatingnetworkareidealanodesnotonlyforhighratelithiumstoragebutalsoforhighpackingdensitiesoftheactivematerials.

  • 标签: 纳米二氧化钛 锂离子电池 高倍率 工程学 电化学性能 纳米TIO2
  • 简介:Sincerateefectofmaterialsplaysakeyroleinimpactengineering,themicroscopicmechanismofrateeffectisinvestigatedatmolecularlevelinthispaper.Theresultsshowthatrateefectonthestrengthofatomicsystemiscloselyrelatedtothecoupledevolutionofatomicmotionsandpotentiallandscapes.Accordingly,itbecomespossibletodevelopanewalgorithmofmolecularsimulation,whichcouldproperlyandefcientlydemonstratestrainrateefectunderawiderangeofloadingratesandunveilthemechanismsunderlyingthestrainrateefects.

  • 标签: 原子运动 景观 应变率效应 进化 速度效应 冲击工程
  • 简介:一台哑的收音机和与普通接收装置同时交流的多重认知收音机被考虑的一种情形。在这份报纸,我们在两添加剂白人Gaussian噪音(AWGN)下面导出多重用户的认知多重存取的隧道(MUCMAC)的一个可完成的率区域隧道和rayleigh褪色隧道,由使用多重用户的联合弄脏编码的纸(DPC)和编码的重叠。通过认知,这被假定第二等的用户(怀疑)能获得主要用户(PU)的消息非有原因地预先准备。用这个方面信息,SUs能执行多重用户DPC从苏避免干扰。而且,SUs能也分配他们的transmit力量的部分帮助PU,用编码的重叠。因此,传统的多重存取的隧道(MAC)的能力区域能被扩大。而且,一些asymptotic结果作为数字被显示出怀疑增加。在AWGN盒子中,PU的最大的可完成的率随数字的增加对数地成长,这被说明,在瑞利盒子中怀疑,我们证明认知获得将与隧道信号减少到噪音比率(SNR)增加。

  • 标签: 瑞利衰落信道 最大速率 多址接入 加性白高斯噪声 发射机 AWGN信道
  • 简介:Atotalof30studentsscoringbetween12and20ontheTestAnxietyScalewhohadbeenexhibitingananxiousstate>24hours,and30normalcontrolstudentswererecruited.IndicesofheartratevariabilitywererecordedusinganActiheartelectrocardiogramrecorderat10minutesbeforeauricularpressing,inthefirsthalfofstimulationandinthesecondhalfofstimulation.Theresultsrevealedthatthestandarddeviationofallnormaltonormalintervalsandtherootmeansquareofstandarddeviationofnormaltonormalintervalsweresignificantlyincreasedafterstimulation.Theheartratevariabilitytriangularindex,very-low-frequencypower,low-frequencypower,andtheratiooflow-frequencytohigh-frequencypowerwereincreasedtodifferentdegreesafterstimulation.Comparedwithnormalcontrols,therootmeansquareofstandarddeviationofnormaltonormalintervalswassignificantlyincreasedinanxiousstudentsfollowingauricularpressing.Theseresultsindicatedthatauricularpressingcanelevateheartratevariability,especiallytherootmeansquareofstandarddeviationofnormaltonormalintervalsinstudentswithpre-examanxiety.

  • 标签: 心率变异性 学生 焦虑 耳穴 标准偏差 协会
  • 简介:Inthispaper,theglobalasymptoticstabilizationbyoutputfeedbackisinvestigatedforaclassofuncertainnonlinearsystemswithunmeasuredstatesdependentgrowth.Comparedwiththecloselyrelatedworks,theremarkablenessofthepaperisthateitherthegrowthrateisanunknownconstantorthedimensionoftheclosed-loopsystemissignificantlyreduced,mainlyduetotheintroductionofadistinctdynamichigh-gainobserverbasedonanewupdatinglaw.Motivatedbytherelatedstabilizationresults,andbyskillfullyusingthemethodsofuniversalcontrolandbackstepping,weobtainthedesignschemetoanadaptiveoutput-feedbackstabilizingcontrollertoguaranteetheglobalasymptoticstabilityoftheresultingclosed-loopsystem.Additionally,anumericalexampleisconsideredtodemonstratetheeffectivenessoftheproposedmethod.

  • 标签: UNCERTAIN nonlinear systems GLOBAL ASYMPTOTIC stabilization
  • 简介:PURPOSE:Weinvestigatethepatternsoffailureinthetreatmentofglioblastoma(GBM)basedonclinicaltargetvolume(CTV)marginsize,dosedeliveredtothesiteofinitialfailure,andtheuseoftemozolomideandintensity-modulatedradiotherapy(IMRT).METHODS:BetweenAugust2000andMay2010,161patientswithGBMweretreatedwithradiotherapywithorwithoutconcurrenttemozolomide.PatientsweretreatedwithCTVexpansionsthatrangedfrom5to20mmusingashrinkingfieldtechnique.PatternsoffailureandtimetoprogressionandoverallsurvivalwerecomparedbasedonCTVmargin,useoftemozolomide,anduseofIMRT.KaplanMeieranalysiswasusedtoestimatesurvivaltimes,andχtestwasusedforcomparisonofcohorts.RESULTS:Forpatientstreatedwith5-,10-,and15-to20-mmCTV,79%,77%,and86%experiencedfailuresinthe60Gyvolume,respectively.Forty-eightpercent,55%,and66%ofpatientswith5-,10-,and15-to20-mmCTVexperiencedfailuresinthe46Gyvolume,respectively.Therewasnostatisticaldifferencebetweenpatientstreatedwith5-,10-,15-to20-mmmarginswithregardto60Gyfailure(P=0.76),46Gyfailure(P=0.51),ormarginalfailure(P=0.73).Eightypercentofpatientsreceivingtemozolomideexperiencedfailuresinthe60Gyvolume.TherewasnoincreasedlikelihoodofmarginalfailuresinpatientsreceivingIMRT(P=0.97).CONCLUSIONS:Moderntreatmenttechniquesincludinguseofconcurrenttemozolmide,limitedCTVmarginsize,andIMRThavenotgreatlychangedthepatternsoffailureofGBM.

  • 标签: 技术包 母细胞 胶质 放疗 放射治疗 替莫唑胺
  • 简介:Whenwetrytoestimatefutureenvironmentalcostsresultingfromourcurrenteconomicactivities,weusuallycalculatethepresentvalueoftheconsequencesforourfuturegenerationsbyutilizingadiscountrateasastandardeconomicprocedure.Thepopularityofthisprocedureissolelysupportedbyitssimplicitywhichassumes:(1)aperfectfinancialmarketovereven100years,and(2)existenceofastabletimepreferencebetweentwoconsecutiveperiodsforanindividualconsumer.Anapparentdeficiencyofthisapproachisthatthepresentvalueoflifequalityoffuturegenerationsvariestoalargeextentalonganarbitrarilychosendiscountrate.Asamatteroffact,thediscountrate,whichcouldreflectthetimepreferenceas2%or5%,matterswhenwepredictcurrentstrategiesofenvironmentalprotectionforfuturegenerations.Simplyapplyingadiscountratetoevaluatethequalityofourfuturegeneration,withoutclarifyingtheactualproductionmechanismbehindthis,isalmosttothesameasignoringthefactthatallofthegoodsareproducedthroughanactualproductionprocessandthatenvironmentaldegradationreducestheefficiencyofthatprocess.Thegreatestconcernforourfuturegenerationsshouldnotbegivenbyanassumeddiscountrate,sincethediscountrateitselfisdeterminedbyfinancialmarketconditionsatcertainpointsintime.

  • 标签: time PREFERENCE DISCOUNT rate NEGATIVE externalities
  • 简介:WithwellsPuguang2and6inthePuguanggasfieldastheresearchobjectsbychoosingorganiccarbonascharacterizationreservoircarbon(indirectlyreflectingthebitumencontents),thispaperdiscussestherelationshipbetweenbitumencontentsandlithologiccharacteristics,reservoircharacteristics,andcalculatesthevolumeofpaleo-oilandoilcrackedgas.Thestudyshowsthattheorganiccarboncontentsofthereservoirsarerelatedtolithologiccharacteristics.Duetovariationsintheparticlesizeorstructureofrocks,theporosityofthereservoirsvaries,furthermore,itwillinfluencethecontentsoforganiccarbon.Andtherelationshipbetweenthesetwoparametersispositive.Basedontheanalysis,therelationshipbetweentotalorganiccarbon(TOC)andthecontentsofreservoirbitumenalsoappearstobepositive.Thevolumeofpaleo-oilandcrackedgasoftheChangxing-Feixian’guanFormationarerespectively495milliontonsand360.4billionm3throughthecalculationofreservoir’sorganiccarbon.Therefore,therelationshipbetweencarbon-bearingrateandcharacteristicsofthereservoirscanbeusedtoindirectlyevaluatereservoirtypes.Besides,thecarbon-bearingrateofthereservoirsalsoreflectsthecontentsofreservoirbitumen,paleo-oilaswellasnaturalgas.Itmakesanewapproachforthestudyofthetypesofreservoirsandtheamountsofpaleo-oilandoilcrackedgasinnortheasternSichuanBasin.

  • 标签: 川东北地区 储层特征 普光气田 含炭 有机碳含量 应用
  • 简介:Thepapermainlystudiesthesum-rateperformanceoflimitedfeedback(LFB)block-diagonalization(BD)inmulti-userdistributedantennasystem(DAS).Asthechannelstateinformation(CSI)fedbacktobasestation(BS)islimited,multi-userinterference(MUI)iscausedinevitablybecauseofthequantizationerror.ConsideringtheinfluenceoftheMUItothecapacityofDAS,weproposeaparameterofeffectivesum-rateratio(ESRR)todenotethecapacityoffsetundertheconditionoftheBScangetperfectCSIandlimitedCSIfirst,thenweconfirmthattheapproximatedESRRisveryclosetoactualESRRgotthroughsimulations.Afterthat,basedontheapproximatedESRR,anadaptiveminimumbitfeedbackschemewhichcaneffectivelyreducetheoverheadoffeedbackchannelandthecomplexityofthesystemisproposed.Simulationresultsshowtheeffectivenessoftheproposedscheme.

  • 标签: SC-FDMA 电信 信号处理系统 通信