简介：Carbon-manganesesteelisoftenappliedincomponentsofpipesinnuclearplant.Ultrasonicfatiguetestsfollowinglowcyclefatigue(LCF)cyclesdamagedareusedtostudythestrengthofveryhighcyclefatigure(VHCF).ThecomparisonoftestresultsofsimpleVHCFandcumulativefatigue(LCFplusVHCF)showsthatLCFloadinfluencesthefollowingVHCFstrength.ContinuumdamagemechanicsmodelisextendedtoVHCFregion.TheeffectofLCFloadonVHCFisstudiedbyanimprovedcumulativedamagemodel.

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简介：Intheapplicationsofaircrafts,automobiles,railways,biomedicineandoff-shorestructures,manycomponentsmayexperiencecyclicloadingconditionsoveralongperiodoftime,runninguptoseveralhundredmillioncycles.1Determinationoflonglifefatiguebehaviorbecomesextremelyimportantforbetterunderstandinganddesignofcomponentsandstructures.

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简介：Thefatiguelifeofnumerousaerospace,locomotive,automotiveandbiomedicalstructuresmaygobeyond10~8cycles.Determinationoflonglifefatiguebehaviorbecomesextremelyimportantforbetterunderstandinganddesignofthecomponentsandstructures.Initially,beforetheinventionofultrasonicfatiguetesting,mostoftheengineeringmaterialsweresupposedtoexhibitfatiguelifeupto10~7cyclesorless.Thispaperreviewscurrentunderstandingofsomefundamentalaspectsonthedevelopmentofacceleratedfatiguetestingmethodanditsapplicationinultra-highcyclefatigue,crackinitiationandgrowthmechanismsofinternalfracture,S-Ndiagram,fatiguelimitandlifeprediction,etc.

简介：Veryhighcyclefatigue(VHCF)behaviorsofbridgesteel(Q345)weldedjointswereinvestigatedusinganultrasonicfatiguetestsystematroomtemperaturewithastressratioR=-1.Theresultsshowthatthefatiguestrengthofweldedjointsisdroppedbyanaverageof60%comparingtothebasemetalandthefatiguefailurestilloccurredbeyond10~7cycles.Thefatiguefractureofweldedjointsinthelowcycleregimegenerallyoccurredatthesolderwhileattheheat-affectedzone(HAZ)intheveryhighcycleregime.Thefatiguefracturesurfacewasanalyzedwithscanningelectronmicroscopy(SEM),showingweldingdefectssuchaspore,micro-crackandinclusionwerethemainfactorsondecreasingthefatiguepropertiesofweldedjoints.Theeffectofweldingdefectsonthefatiguebehaviorsofweldedjointswasdiscussedintermsofexperimentalresultsandfiniteelementsimulations.

简介：Duty-cyclemodulationalternatelyblowingfromtwoopposite-facingplasmaactuatorsontheleewardsurfaceneartheapexofaconewitha10semi-apexangleisadoptedtocontrolmeanlateralforceandmoment,andtheflowcontrolmechanismsarepresented.Pressuredistributionsovertheforebodyoftheconearemeasuredbysteadypressuretappings.Theexperimentsareperformedina3.0×1.6mopen-circuitwindtunnelatawindspeedof20m/s,a45angleofattackandaReynoldsnumberof2×105,basedonthediameterofthebaseofthecone.Almostlinearlyproportionalcontrolofthelateralforcesandmomentsoveraslenderconicalforebodyatahighangleofattackhasbeendemonstratedbyemployingapairofsingledielectricbarrierdischargeplasmaactuatorsneartheapexofthecone,combinedwithaduty-cycletechnique.Thepressuredistributionmeasurementsindicatethatthebi-stablevortexpatternappearstobeshiftedintheoppositedirectionwhentheportorstarboardactuatorisactivated,whiletheotheriskeptoffduringthetest.Itisshownthatthereducedpulse-repetitionfrequencybasedonthelocaldiameterattheplasmaactuatorequaltooneyieldsthehighesteffectivenessamongthecasesconsidered.

简介：有最不消费精力和最大的效率的液化天然气(LNG)的适当生产是相当重要的。在这份报纸，借助于APCI过程的LNG生产周期被学习了。在APCI周期的每台设备的精力平衡方程和exergy平衡方程被建立。设备用严密热力学被描述，没有重要简化被假定。作为关键参数拿一些操作参数，性能(警察)和串联周期的exergy效率的系数上的这些参数的影响被分析。结果显示那个警察和exergy效率将与增加先生的入口压力被改进(混合致冷)压缩机，在precooling过程以后NG和先生减少，汽轮机的插头压力，先生压缩机的入口温度和在在主要的低温实验法的热exchanger(MCHE)冷却以后的NG温度。分别地，警察和APCI周期的exergy效率将在优化关键参数以后超过2%和40%。

简介：米饭镉(Cd)敏感变异的cadB-1用Agrobacteriumtumefaciens被获得调停的系统。在cadB-1和野类型(WT)的暴露以后米饭幼苗到为有增加外部Cd集中的cadB-1和WT的10d，在根积累到高水平的Cd，茎和叶子的Cd集中的一个范围，并且在cadB-1的幼苗生长的抑制比在WT更严肃。氢过氧化物累积在cadB-1的叶子和根是更高的。减少的谷胱甘肽(GSH)的比率/oxidized谷胱甘肽(GSSG)，ascorbate(ASC)/dehydroascorbate(DHA)和减少的菸碱腺嘌dinucleotide磷酸盐(NADPH)/oxidized菸碱腺嘌dinucleotide磷酸盐(NADP+)在高Cd层次下面在叶子和根两个都比在WT在cadB-1是更低的。ascorbateperoxidase(APX)的活动，谷胱甘肽peroxidase(GR)，dehydroascorbatereductase(DHAR)和monodehydroascorbatereductase(MDHAR)在Cd的高水平的处理下面在叶子和根两个都比在WT在cadB-1是也更低的。我们的结果建议在Cd应力下面，ASC-GSH周期更严重比在WT在cadB-1被禁止，显示变异的cadB-1不太能清除反应的氧种类并且对Cd敏感。

简介：三个米饭变化，Zhonghan3，Shanyou63和Aizizhan，当在检测微分活跃甲基的材料骑车并且响应干旱应力转移相关基因表示，被使用。实验被在干旱的条件下面的微分显示器技术与10%PEG6000答案模仿了的基因薄片和mRNA执行。结果显示甲基周期能在Zhonghan3和Shanyou63的叶子被激活，但是在干旱应力下面在Aizizhan的叶子禁止了。而且，干旱应力能导致很多methyltransferase基因的表示，特别Rubisco蛋白质methylation的抄写联系了基因，它是有益的因为Rubisco蛋白质氧化和降级的预防，和干旱应力能禁止DNAmethyltransferase基因和histonemethyltransferase基因的抄写。这结果证实活跃甲基骑车并且转移相关基因涉及米饭干旱抵抗。

简介：Veryhighcyclefatigue(VHCF)propertiesofalowtemperaturetemperingbearingsteelGCr15withsmoothandhole-defectspecimensarestudiedbyemployingarotarybendingtestmachinewithfrequencyof52.5Hz.Bothsmoothandhole-defectspecimensbreakinVHCFregimewithsomedifferenceinfatiguecrackinitiation.Forsmoothspecimens,afinegranulararea(FGA)isobservednearthegrainboundaryinthefracturesurfaceofthespecimensbrokenafter10~7cycles.ButnoFGAisobservedinthehole-defectspecimensbrokeninVHCFregime,andtheVHCFcrackdoesnotinitiatefromthesmallholeatthesurfaceasitdoesatloworhighcyclefatigueregime.InternalstressisemployedtoexplaintheVHCFbehaviorofthesetwotypesofspecimens.Atlast,anadvanceddislocationmodelbasedonTanakaandMuramodelisproposedtoillustratetheinternalstressprocessandtopredictfatiguecrackinitiationlifewithFGAobservedinthefractureregion.

简介：Amodelisproposedtocorrelatethecrackgrowthrateandstressratiocontainingveryhighcyclefatigueregime.Themodelisverifiedbytheexperimentaldatainliterature.Thenaformulaisderivedfortheeffectofmeanstressonfatiguestrength,anditisusedtoestimatethefatiguestrengthofabearingsteelinveryhighcyclefatigueregimeatdifferentstressratios.TheestimatedresultsarealsocomparedwiththosebyGoodmanformula.

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简介：Veryhighcyclefatiguebehaviorsoftwobainite/martensitedual-phasesteelswereinvestigated.Oneofthesteelswascyclicrapidheattreatedanditsmicrostructureswererefined.Fatiguestrengthofthesteelis225MPahigherthanthatwithoutrefining.Observationoffracturesurfacesshowthatthefatiguecracksinitiateatbainitesfornon-refinedsteelandatnon-metallicinclusionsfortherefinedsteel.Thesizeofinclusionsismuchsmallerthanthatofbainiteswhichresultsintheimprovementoffatiguestrength.