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简介：在《英文角斗场》中,每篇文章都是精选自英美中小学生的读物和教材噢。想知道自己的英语水平有多高,就来试试吧。

简介：近两年英美文教专家来青岛任教,使我们有机会接触到他们使用的clozesheet,skimmingreading,roleplay,counsellinglearning,stripdialogue等许多新鲜的教学方法和技巧。这些方法和技巧的主要特点是实践性强,能充分调动学生学习的积极性,故可供教育工作者尤其是我们外语教师参考和借鉴,也有助于我们去探索外语教学改革的方向和途径。

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简介：Intheexperimentwehavemeasuredtheresonantfrequenciesofper-foratedsheetswithperforationratesfrom0.008to0.30.Comparedthosefre-quencieswiththecorrespondingresonantfrequenciesofhomogeneous,orun-perforatedoneweobtainedanempiricalrelationshipbetweentheresonantfrequencyandperforationrate,whichcanbeusedforindustrialpurpose.Wehavealsostudiedthechangeofvibrationalenergydistributionofperforatedsheetrelatedtothatofhomogeneous.

简介：IntroductionRecently,bonemarrowmesenchymalstemcells(MSCs)havebeenreportedtorepairchronicallyinfractedmyocardiumwithdirectinjection.However,itisverydifficulttolocalizetheinjectedcellsontotheischemicareatoregeneratesufficientcardiacmassinthethinnedscararea.Toovercometheproblem,wehaveutilizedourcellsheettechnologybasedontemperature-responsiveculturedishes.Whentheculturetemperatureisreducedfrom37℃to20℃,allcellsconnectedviacell-celljunctionproteinsareharvestedasasinglesheetwithoutusingproteolyticenzymes.Thistechnologyallowsustotransplantstemcellsinvivofortreatmentheartdiseasewithouttheproblemsmentionintheprevious.MethodsMaleClawnminipigswereusedinthisstudy.Bonemarrow(5-7mL)wascollectedundergeneralanesthesia.Histopaqe-1077(15mL),wereaddedtobonemarrowandcentrifuged.Thecellswerecollectedandculturedfor7days.Weseededthebonemarrow-derivedMSCsattheconcentrationof(6×10~5/ml)on60mmdiametertemperature-responsivedishesfor7days.Astheculturetemperaturedecreasedfrom37℃to20℃,MSCsheetdetacheditselfspon-taneouslyandfloatedupintotheculturemedium.Triplelayerswerestackedtogetherrepeatedlyformingspecialmultiplayer.Myocardialinfarctionwascreatedbytheligationoftheleftanteriordescendingbranchoftheleftcoronaryartery.Acellsheetswastransplantedontotheischemiaarea.Theechocardiographywasperformedtwoandfourweeksaftertransplantation.Thehearttissuewithcellsheetswereremovedandfixedwith10%formalinforhistologicalanalysisonemonthafterthetransplantationofcellsheets.ResultsMostMSCsarepositiveforCD29,CD90,CD146andCD73.ThesemeantheculturecellsheetswerecomposedofundifferentiatedMSCsandremainedmultipotent.Monolayers(20-30μm)andmultilayer(120μm)cellsheetswereproduced,whichretainedallcell-to-cellcontaction.Histologicalanalysesshowthecellsheetsbecomecloselycontactedwiththehearttiss

简介：LetW~{W(t);t∈RN+}bethed-dimensionalN-parameterBrownianSheet.SufficientconditionsforacompactsetFRd\{0}tobeapolarsetforWareproved.Itisalsoprovedthatif2N≤d,thenforanycompactsetER＞N,inf{dimF:F∈B(Rd),P{W(E)∩F≠φ}＞0}=d-2DimE,andif2N＞d,thenforanycompactsetFRd\{0},inf{dimE:E∈B(R＞N),P{W(E)∩F≠φ}＞0}=d/2DimF/222,whereB(Rd)andB(RN＞)denotetheBorelσ-algebrainRdandR＞Nrespectively,anddimandDimareHausdorffdimensionandPackingdimensionrespectively.

简介：InOctober1991,PresidentBorisYeltsininitiatedaprogramofradicaleconom-icreformatthefifthsessionoftheoldparliament,theCongressofthePeople’sDeputies,andintroducecdtheso-called“shocktherapy”throughoutthecountryonJanurary2thefollowingyear.Theprogramaimsattherealizationofatransitionfromaplannedeconomytoamarketonewithinashortspanoftime

简介：学习shear不稳定性的传统的Kelvin-Helmholtz观点不对与联系的盒子合适砍有大风的线在旋涡表砍。从那以后，shear不稳定性成为旋涡表的theinstability。如果速度被旋涡表导致，不平等(1？Rr+Rid)>0并且U(v，t)>U((t))成为旋涡表不稳定性的标准。这个标准显示那1)环境地的布置制止沿着shear线发展的骚乱。2)在那里多存在在shear的不稳定的过程的鈥攕c淡色啤酒相互作用排队。为不稳定性的必要条件的计算也在这篇论文被介绍。关键词砍线-导致的速度-旋涡表的不稳定性这个工作被工程在严重MesoscaleCovective的动态学习上在资助G1998040907下面并且由关键工程在中国在构词的机制和重要气候和天气灾难的预兆的理论的学习上支持系统在资助No.49735180下面由中国的国家自然科学基金会赞助了。

简介：稳固的墙上的表成穴的开始的预言被认出了很困难，自从它被边界层流动显著地影响特征，免费原子核的人口，原子核控制了墙粗糙，在液体的溶解空气的数量等等。开始怎么被水质量和背景流动的条件影响，足够地没被弄明白特征。在这研究，高从免费原子核加速表洞的开始的观察被进行为一二维会聚--分叉的嘴流动，表洞在此就嘴喉咙下游地形成。表成穴的开始进程上的溶解空气和免费的流速度的数量的效果被检验。另外，水泡原子核密度，众所周知是为成穴开始的重要因素，被在隧道安装的过滤器消极地控制。从观察，原子核数字密度显著地影响表洞而非另外的二个参数的形成，这被证实。在与大原子核数字调节密度，表洞不形成，并且冒泡的成穴相反出现。在有小原子核数字密度的情况中，表洞从一个单个流动原子核形成并且streamwisely并且spanwisely发展。处于有中等原子核数字密度的条件，表洞也形成，但是是shorter/更狭窄的streamwisely/spanwisely，由于流动在形成的表洞附近的另外的原子核的相互作用。

简介：Alargemagnetizedplasmasheetwithsizeof60cmx60cmx2cmwasgeneratedbyalinearhollowcathodedischargeundertheconfinementofauniformmagneticfieldgeneratedbyaHelmholtzCoil.Themicrowavetransmissioncharacteristicoftheplasmasheetwasmeasuredfordifferentincidentfrequencies,incaseswiththeelectricfieldpolarizationoftheincidentmicrowaveeitherperpendicularorparalleltothemagneticfield.Inthismeasurement,parametersoftheplasmasheetwerechangedbyvaryingthedischargecurrentandmagneticfieldintensity.Intheexperiment,upperhybridresonancephenomenawereobservedwhentheelectricfieldpolarizationoftheincidentwavewasperpendiculartothemagneticfield.Theseresonancephenomenacannotbefoundinthecaseofparallelpolarizationincidence.Thisresultisconsistentwiththeoreticalconsideration.Accordingtotheresonancecondition,theelectrondensityvaluesattheresonancepointsarecalculatedundervariousexperimentalconditions.Thiskindofresonancephenomenacanbeusedtodevelopaspecificmethodtodiagnosetheelectrondensityofthismagnetizedplasmasheetapparatus.Moreover,itispointedoutthattheoperatingparametersofthelargeplasmasheetinpracticalapplicationsshouldbeselectedtokeepawayfromtheupperhybridresonancepointtopreventsignalsfrompolarizationdistortion.

简介：Thispaperdiscussestheresultsoftestsontheshearcapacityofreinforcedconcretecolumnsstrengthenedwithcarbonfiberreinforcedplastic(CFRP)sheet.ThesheartransfermechanismofthespecimensreinforcedwithCFRPsheetwasstudied.ThefactorsaffectingtheshearcapacityofreinforcedconcretecolumnsstrengthenedwithCFRPsheetwereanalyzed.Severalsuggestionssuchasthenumberoflayers,widthandtensilestrengthoftheCFRPsheetareproposedforthisnewstrengtheningtechnique.Finally,asimpleandpracticaldesignmethodispresentedinthepaper.Thecalculatedresultsofthesuggestedmethodareshowntobeingoodagreementwiththetestresults.ThesuggesteddesignmethodcanbeusedinevaluatingtheshearcapacityofreinforcedconcretecolumnsstrengthenedwithCFRPsheet.

简介：Inthisstudy,theformabilityoftransformation-inducedplasticity(TRIP)steelisstudiedduringdeep-drawingprocesseswithpreforming.Theeffectsofpreformingontheminimumthicknessofcanareinvestigatedwithaconstitutivemodelaccompanyingstrain-inducedmartensitetransformationinprestraincondition.TheconstitutivemodelhasbeenimplementedintoABAQUS/UMATforanalysisofTRIPsteel-formingprocesses.TheresultsshowthatpreformingslightlyinfluencesthethicknessuniformityofTRIPsteel...

简介：Samplesofthecrosssectionmicrostructuresofgalvannealedsteelsheetsthatlackalloyingwereanalyzed.X-raydiffraction(XRD)testswerecarriedout.Thestudydiscoversthatthedeficitofalloyingwashigheronbothsidesofthesteelsheetwhencomparedtothecenterandthethicknessofthecoatingonthesideswasalsohigherthanthecenter.TheresultsoftheXRDtestsdemonstratethatthemicrostructureofthecoatingwithalackofalloyismainlycomposedofzinc,ζandδ.Theyalsoindicatethatthelackofalloyingismainlyduetoalowergalvannealingtemperatureandthickercoating.Itisshownbytheopticalmicrographsofcoatingthattheδphaseformsfirstinadiscontinuousmannerattheinterfaceandthenrapidlypushestowardsthecoatingandenlarges.

简介：这篇论文为认出论述一条途径孤立并且部分的形式自由的表面模型的交叉几何特征，为自动化表金属形成计划的过程的目的。发达方法论有三主要的步：B花键表面，伸出和消沉的察觉，和为形成领域的表金属的几何特征的识别的分。部分的输入几何学数据格式基于在整修B花键表面形式代表的一个IGESCAD表面模型。每表面在使用B花键表面的符号的计算获得的弯曲性质表面的帮助下被分类或细分进不同弯曲区域。那些区域令人满意一种特别几何学和拓扑学关系作为伸出和消沉(DP)形状被认出。DP形状然后用一条基于规则的途径被分类进不同几何特征。A证实发达方法的可行性学习也被介绍。

简介：High-strengthsteelshavebeenattractingmoreandmoreattentionofpeople,Unfortunately.deteriorationofductilitylimitedtheirapplications.Tosolvethisproblem,anano-structuredstainlesssteelsheetisdevelopedtocombinehighstrengthandhighductility.Processingofthesurfacemechanicalattritiontreatment(SMAT)wasintroducedtoobtainanano-grainlayeronthedoublesurfaceofthestainlesssteelsheet.Themicrostructureofthenanostructuredsteelsheetischaracterizedbyanalternatedistributionofcoarsegrainedlayerandnanocrystallinelayer.Thenthedualsurfacenano-crystallizedstainlesssteelsheetswereco-warmrolledat500℃.Theexperimentalresultsrevealthatthemechanicalpropertiesofthenanostructuredsteelexhibithighyieldstrengthintherangeof700-950MPaandtensilestrengthhigherthan930MPa.Moreover,elongationtofracturereachesto15%-48%,togetherwithauniformelongationstabilizedto13%-45%.

简介：Sinceithasexcellenttensilestrength,thequenchingandpartitioning(Q&P)treatedsteelhasbeenwidelyacclaimed.SomeresearchediscurrentlybeingconductedonQ&Psteel,butQ&Ptechniquesandrelatedmechanismshavebeenmostlyresearchbasedonconventionaltransformation-inducedplasticity(TRIP)steel.ThisstudyresearchestheeffectofMnonthepropertiesofQ&Psheetsteel.TwokindsofsteelsheetwithdifferentlevelsofMncontent(1.46%Mnand2.75%Mn)areinvestigated.Afterbeingfullyannealed,thesteelsheetswerequenchedtoatemperaturebetweenMsandMf.Allocationtreatmentthencausedthecarbontobepartitionedintotheremainingaustenite.Themicrostructureandtensilepropertieswereanalyzed.TheresultsshowthattheincrementofMncontentcanincreasethestabilityofthesteelanddecreasethesensitivityofthequenchingtemperature(QT).TheresultsalsoindicatethatincreasingthelevelofMncaneffectivelysuppresstheformationofbainite.

简介：题目：水下板桩叶片对移动河床的影响研究　　目的：比较板桩叶片和简单的平板叶片在控制河床沉积物再分配时的效率。　　方法：1.在不受当地侵蚀现象影响的接近障碍物和下游区域的直线水道中研究河床的形态；2.使用不同的实验装置测试简单几何形状的平板叶片和复杂形状的603K叶片的性能；3.在不同的叶片迎角和浸没参数下，测试与其面积接近的结构和在远场中的河床形态。　　结论：1.叶片的形状和迎角影响其对河床形态所产生的作用，尤其是对于较大的淹没参数而言；2.平板叶片和板桩叶片对下游河床的重塑作用相似；3.随着迎角的增加，平板叶片将造成更深的冲刷孔。这可能归因于与平板叶片相关的马蹄形涡流增加的侵蚀能力，而板桩叶片的不均匀表面可减轻该涡旋的侵蚀强度。

简介：我们分析磁电机尾巴水流表的垂直结构为两次间隔在哪个期间簇太空船在一安静时间穿过中立的表。Inthe间隔，慢慢地移动的当前的表，和AE的价值索引是相对小的，关于40-130nT。我们发现当前的表的二个例子，与在磁性的赤道的当前的密度最大值(B-x=0)，以及离开中心的一个例子或区分的电流表。在安静时间，没有任何快血浆流动并且没有重要flapping运动，我们直接也观察了区分的当前的表。区分的当前的表可能在当前的表在稳定性以内被联系。这些可能为研究当前的表分叉的机制是重要的。

简介：Throughsamplingfromdifferentdepthanddifferentzonesinthezincbath,thesizedistributionofdrossparticlesbuiltduringgalvannealed(GA)productionisanalyzedandcomparedwiththatduringgalvanized(GI)production.TherelationshipbetweenthedrossformationduringtransitionsfromGAtoGIandtheeffectiveAlofthemeltisdiscussed.Finally,thecharacteristicsofdrossparticlesinGAcoatinganditseffectsonGApunchingandpaintingperformancesarestudied.