简介：一ARCH模型及其扩展模型为了模拟波动的集群性,Engle提出了ARCH模型,允许条件方差作为过去误差的平方的函数随时间变化.

简介：Atestforlinearityintimeserieswithβ-ARCHerrorsisproposedinthispaper.Theempiricalpercentagepointsfortsetstatisticarealsogiven.Thesimulatingresultsundernormalandnon-normalerrordistributionsshowthattestsuggestedbyusisverypower

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简介：Currently,thereareawiderangeoflinetypesinthefieldofarchdamdesigningandconstruction,andeachofthemmayhavetheirownstrengthandweaknessdisparately.Atrade-offbetweenthesize,stress,aswellastheconstructioncostandcomplexityofthedamneedstobemadeinordertoarriveatanewsolutioncalledthecycloidarchdam.ThroughredevelopmentofVBAusingAutoCAD,thearchringandthecenterofthearchlinehavebeendesigned.Also,thestressanalysisonparabolaandcycloidhavebeendone,whichprovidesatheoreticalprinciplethatthecycloidcouldberegardedasanewlinetypeofthearchdam.

简介：Aseismicstabilityassessmentofarchdam-foundationsystemsispresentedusingacomprehensiveapproach,inwhichthemainfactorsthatsignificantlyinfluencetheseismicresponseofanarchdam-foundationsystemareconsidered.Alargescalefiniteelementmodelwithover1milliondegreesoffreedomisconstructedfortheBaihetanarchdam(289mhigh),whichisunderconstructionintheSouthwestofChina.Inparticular,thecomplicatedgeologicalconditionswithfaultsintersectinginterlayershearweaknesszonesatthedambaseandthedamabutmentresistingforcebodyismodeledintheanalysis.Threeperformanceindicesareadoptedtoassesstheseismicstabilityofthearchdam.TheresultsdemonstratethattheopeningofthejointsoftheBaihetanarchdamissmallandthewaterstopinstalledbetweenthejointswouldnotbetornduringadesignearthquake.Theyieldingformedintheinterfacebetweenthedamandfoundationdoesnotreachthegroutingcurtainthatwouldremaininanelasticstateafteranearthquake.Theyieldingzonesoccurringontheupperportionofthedamfacesextend1/8thicknessofblocksectionintothedambodyandthuscantileverblocksneednotbeconcernedwithslidingstability.Thefaultsandinterlayershearweaknesszonesinthenearfieldfoundationexhibitsevereyielding,andapotentialslidingsurfaceispenetrated.Althoughthefactorofsafetyagainstslidingofthesurfacefluctuateswithadecreasedtrendduringanearthquake,theminimuminstantaneousvaluereaches1.02andisstilllargerthan1.0.Therefore,aconclusionisdrawnthattheBaihetanarchdam-foundationsystemwillremainstableunderthedesignearthquake.

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简介：本文利用GARCH类模型，分析了上海股票市场和深圳股票市场的波动特徵，并对二者进行比较，提出了一些政策建议。应规范股票市场，避免大起大落。

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简介：Shakingtabletestsofa1:10scalearchmodelperformedtoinvestigatetheseismicbehaviorandresistanceofconcretefilledsteeltubular(CFT)archstructuresaredescribedinthispaper.TheEl-CentrorecordandShanghaiartificialwavewereadoptedastheinputexcitation.Theentiretestprocesscanbedividedintothreestagesdependingonthelateralbraceconfigurations,i.e.,fully(five)braced,twobracesremoved,andallbracesremoved.Atotalof46tests,startingfromtheelasticstatetofailurecondition,havebeenconducted.Thenaturalvibrationfrequencies,responsesofacceleration,displacementandstrainweremeasured.Fromthetestresults,itisdemonstratedthattheCFTarchstructuresarecapableofresistingseveregroundmotionsandthatCFTarchesofferacrediblealternativetoreinforcedconcretearches,especiallyinregionsofhighseismicintensity.

简介：根据文学，仅仅关于渗透胸的主动脉的损伤的出现的一个小比例能成功地被对待。此处，我们报导我们缺乏的一所农村医院里的如此的一个病人的最近的营救的经验推进了仪器为心肺绕过操作。20岁的男性在在无名的动脉和左普通颈动脉动脉之间的大动脉的拱门上和1.5厘米的撕裂与破坏无名的静脉和恰好普通的颈动脉动脉为渗透的损害被招收。没有实现，病人成功地被救心肺绕过。在这种情况中的表示和管理被讨论。

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简介：Background:Thisprospectivestudyexploredtheeffectsofendurancerunning(ER)inminimalversusstandardrunningshoesonthefoot'ssuperficiallayerintrinsicmusclesandthefunctionofthelongitudinalarch.Ourhypothesiswasthatrunninginminimalshoeswouldcausehypertrophyinthesemusclesandleadtohigher,stronger,stifferarches.Methods:Thehypothesiswastestedusingasampleof33healthyrunnersrandomizedintotwogroups,acontrolgroupshodintraditionalrunningfootwearandanexperimentalgroupshodinminimalsupportfootwear,whosefeetwerescannedinanMRIbeforeandaftera12-weektrainingregime.Runningkinematicsaswellasarchstiffnessandheightwerealsoassessedbeforeandafterthetreatmentperiod.Results:Analysisofanatomicalcross-sectionalareasandmusclevolumesindicatethattheflexordigitommbrevismusclebecamelargerinbothgroupsby11%and21%,respectively,butonlytheminimallyshodrunnershadsignificantarealandvolumetricincreasesoftheabductordigitiminimiof18%and22%,respectively,andsignificantlyincreasedlongitudinalarchstiffness(60%).Conclusion:Theseresultssuggestthatendurancerunninginminimalsupportfootwearwith4mmoffsetorlessmakesgreateruseofthespringlikefunctionofthelongitudinalarch,thusleadingtogreaterdemandsontheintrinsicmusclesthatsupportthearch,therebystrengtheningthefoot.

简介：Becauseofitsgoodconditionwithmechanics,logarithmicspiraldoublecurvearchbamhasbeenwidelyusedinthepracticalengineering.Theintroductionofanewmethodinhowtodividetransversejointinarchdamwillbegivenandthefurtherresearchofitscalculationhasbeendone.TheC++isusedinelectronicprocedureandthe3DsimulationhasbeenfinishedwithAutoCAD,whichwillprovidetheobjectmodelforcomputersimulationofthearchdamandthedivisionoffiniteelementmesh.Meanwhile,thismethodindividingthetransversejointinarchdamalsocanbetakenasthecalculatedbasisforthedesignandcalculationofarchdam,constructionloftingandthecalculationoftheworkamount.

简介：<正>OnNovember12thisyear,JinpingCascadeIHydropowerStation,seatedonthelowerreachesofYalongRiverinSichuanProvince,startedtobeconstructed.ThestationisthesecondlargehydropowerprojecttobeconstructedonYalongRiverfollowingErtanHydropower

简介：ThecalculationofultimatebearingcapacityisasignificantissueinthedesignofConcreteFilledSteelTubular(CFST)archbridges.Basedonthespacebeamtheory,thispaperprovidesacalculationmethodfordeterminingtheultimatestrengthofCFSTstructures.Theaccuracyofthismethodandtheapplicabilityofthestress-strainrelationshipswerevalidatedbycomparingdifferentexistingconfinedconcreteuniaxialconstitutiverelationshipsandexperimentalresults.Comparisonoftheseresultsindicatedthatthismethodusingtheconfinedconcreteuniaxialstress-strainrelationshipscanbeusedtocalculatetheultimatestrengthandCFSTbehaviorwithsatisfactoryaccuracy.Thecalculationresultsarestableandseldomaffectedbyconcreteconstitutiverelationships.Themethodisthereforevaluableinthepracticeofengineeringdesign.Finally,theultimatestrengthofanarchbridgewithspanof330mwasinvestigatedbytheproposedmethodandthenonlinearbehaviorwasdiscussed.

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