简介：众所周知，口语是BEC四个单元中挑战性较大的一部分，并且口语考试的难度随着等级的提高而加大。BEC口语考试分为三部分。第一部分是考生与考官的交流，着重于个人情况，比如学习工作，兴趣爱好。这一部分必须充

简介：Lowpoweraddercircuits,SERF,10T-Ⅰ,10T-Ⅱ,10T-Ⅲandacomplementaryadder(28T)atphysicallayoutlevelareevaluated.Simulationsbasedontheextractedaddercircuitlayoutsareruntoassesshowvariouscircuitsetupscanimpactthespeedandpowerconsumption.Inaddition,impactsofoutputinvertersonthecircuitperformanceofmodifiedSERFand10Taddersduetothresholdlossproblemarealsoexamined.Differencesamongtheseaddersareaddressedandapplicationsoftheseaddersaresuggested.

简介：Inthisstudy,Nocolokeutecticflux,usedwidelyintheprocessofthebrazingofaluminumanditsalloy,waspreparedbythereactionbetweenAl(OH)3/KOHresolutionandHF.AseriesofKF-AlF3eutecticproductionsatvariousreactiontemperatureswereprepared.Themeltingpointsoftheproductsweremeasuredbydifferentialthermalanalysis(DTA),andthecompositeswerecharacterizedbyX-raydiffraction(XRD).TheresultssuggestthatthetemperaturecontrolisimportanttoproduceanidealfluxconsistingofK2AlF5,H2OandKAlF4,withalowmeltingpointof560℃,whichissuitableforthebrazingofaluminumanditsalloyasthealuminumfluxes.

简介：Thispaperpresentsaninvestigationonstrengthofcementdeepmixing(CDM)mixture.Fourtypicalworksofoffshoreorland-basedprojectsareintroduced.Withsamplesfromtheseprojectsandlaboratorytests,statisticalanalysisismadeontheincrementlawofthestrengthofcement-soilmixturewithdifferentamountofcement,andstrengthsunderdifferentworkingconditionsarecompared.Itisfoundthattheamountofcementinthecement-soilmixtureiscloselyrelatedtotheunconfinedcompressivestrengthofthemixture.Attheageof90d,theunconfinedcompressivestrengthofthecement-soilmixtureincreasedby0.054Mpa-0.124Mpawitheachcementincreasing10kg/m3inthecement-soilmixture,averagelyincreasedby0.085Mpa,whilethatattheageof120dincreasedby11%incomparison.Thequalityofthecement-soilmixtureshouldbecomprehensivelyevaluatedinaccordancewiththetrimmedaverageofstrength,coefficientofvariationandrockqualitydesignation(RQD)indicatorsofsamplingratio.

简介：BasedonthedesiltingresearchofoneschedulingprojectinthesouthwestofChina,themethodofsettinggriddesiltinggallerybeforethedesiltingtunnelisputforwardtoexpandthescopeofthescouringfunnelbeforethedamandsolvetheproblemofsedimentdepositionatthepowerstationwaterintake.Theexperimentalresultsshowthat,inthedesignofagriddesiltinggallery,thewidthofthegridgalleryshouldnotbesmallerthanthatofthedesiltingbottomintake,thesizeofthegridorificeshouldbeintherangeof1.5,m—2.0,malongtheflowdirection,andthegridspacingshouldbe3—5timesthesizeofthegridorifice.Thedischargingabilityofthedesiltingbottomintakewilldecreaseafterthegriddesiltinggalleryisadded.Theaverageofthedecreaseratesisabout5%—10%.Thescouringfunneldrawsinthelongitudinaldirectionbeforethedamobviouslyaftertheconstructionofthegriddesiltinggallery.

简介：Theinfluenceofexternallowfrequency(0-100Hz)vibrationonthetip-sampleinteractioninSPMisthemainconcernofthispaper.Aconcept,vibrationrejectionratio(VRR)proposedbyThompsonetal,wasinvestigatedtheoreticallyandexperimentally.Aconcisetheoreticalbackgroundwasintroduced,avibrationstimulatingandmeasuringsystemforSPMwasbuiltup,andanexperimentalresearchoftheinfluenceonSPMVRRwascarriedoutwithdifferentSPMprobes,samples,tippre-loadsandopen/closeloopsoftip-sampleinteraction.ItwasprovedbothintheoryandexperimentthatSPMVRRhadcorrelationswiththespringconstant,theairdampingconstant,theeffectivemassofthecantilever,thecontactspringconstantandthecontactdampingconstantbetweentipandsample.SPM'svibrationrejectingabilitycanbeimprovedbylongercantileverprobe,softersamplesurface,greatertippre-load,andclose-loopcontrolfortip-sampleinteraction.Moreattentionshouldbepaidtoapropercombinationoftheaboveparameters.

简介：浸透的软泥土的失败标准通过不同实验在周期的负担下面被学习。很多周期扭力砍，在unconsolidatedundrained状况下面的浸透的软泥土上的周期的triaxial测试被进行。从测试结果分析，在静态、周期的负担下面的浸透的软泥土的失败满足协定标准，这被看见。来自不同测试压力状态的结果不与测试压力状态或限制压力有关。它能处于一般压力状态被使用。然后根据协定标准，在在测试压力状态和一般压力状态之间的失败时刻的相等的关系能被建立。在失败时刻的浸透的软泥土的周期的力学特征因此在这篇论文被澄清。而且，一个理论基础用伪静电干扰被提供elasto塑料的周期的力量模型评估周期的适用的能力。

简介：UsingaHamburgwheel-traektestdevice,theresistancetoruttingofGussasphaltistestedandcompared.Gussasphaltwithhardbitumenhasgoodresistancetorutting.TherelatedresistanceabilitiestocrackingatlowtemperatureofGussasphaltaretestedandcomparedthroughflexuralexperimentsandthecompositestructurefatiguetestwithtemperaturedropping.Gussasphaltwithhighpedormaneepolymermodifiedbitumenhasalongerfatiguelifeandalowerbreakingtemperature;theycanbeusedinthefuturesudacesforsteelbridgedecksinGermany.

简介：Theiron-loadedorganicphaseofnaphthenicacid-isooctylalcohol-kerosenewasprepared,andtheprocesskineticsofhydrothermalstrippingofironfromthephasewasstudied.Severalfactorsaffectinghydrothermalstripping,suchasthepolymerofnaphthenicacid,initialconcentrationsofironandnaphthenicacid,temperatureandagitationtime,wereinvestigated,andbasedonexperimentalresultsandtheoreticalanalysis,twokineticmodelswereestablished.Thestrippingrateequationsuggeststhatthehydrothermalstrippingprocessactivationenergyis96.4kJ·mol-1andthestrippingiscontrolledbyhydrolysisofnaphtheniccomplexofiron.Thevaluescalculatedbythestrippingfractionequationcomparativelyaccordwiththeexperimentaldata.

简介：Weconductedatransientexperimentalinvestigationofsteam–waterdirectcontactcondensationintheabsenceofnoncondensiblegasinalaboratory-scalecolumnwiththeinnerdiameterof325mmandtheheightof1045mm.Weappliedanewanalysismethodforthesteamstateequationtoanalyzethemolarquantitychangeinsteamoverthecourseoftheexperimentanddeterminedthetransientsteamvariation.Wealsoinvestigatedtheinfluenceofflowratesandtemperaturesofcoolingwaterontheefficiencyofsteamcondensation.Ourexperimentalresultsshowthatappropriateincreasingofthecoolingwaterflowratecansignificantlyacceleratethesteamcondensation.Weachievedarapidincreaseinthetotalvolumetricheattransfercoefficientbyincreasingtheflowrateofcoolingwater,whichindicatedahigherthermalconvectionbetweenthesteamandthecoolingwaterwithhigherflowrates.Wefoundthatthetemperatureofcoolingwaterdidnotplayanimportantroleonsteamcondensation.Thismethodwasconfirmedtobeeffectiveforrapidrecoveringofsteam.

简介：这研究通过数字模拟在一个圆形的热exchanger试管调查了热转移和一个种swirl发电机的流动特征。这类swirl发电机导致的swirl流动能与最小的压力落下惩罚获得高热转移率。模拟被执行理解这种mesoscale热改进部件的物理行为。由设想热转移和流动特征，swirl流动被导致由，这被发现打漩在圆形的试管的生成器结合侵犯的喷气效果。在通过swirl生成器以后，液体的本地磨擦因素能快速更快速回到底层，当本地Nusselt数字为距离维持更高的值时；因此，本地性能的评估标准被改进。单个因素的优化被用于三个几何参数，即，角度打漩生成器(25o，45o，和60o)，长度打漩发电机(0.005，0.01，和0.02?m)，并且中心杆半径(1，2，并且3?公里)。为在一个圆形的试管的空气的laminar流动的swirl生成器的最佳参数被获得，它应该是60o，0.005?m，并且3?公里分别地。

简介：微尺寸的试管热exchanger(MTHE)被制作，并且它在转移和压力掉的发情的表演试验性地被学习。MTHE试管的方面上的单相的强迫的传送对流热转移关联被建议并且与在雷纳兹数字的以前的试验性的数据相比变化5001800。在计算Nusselt数字的关联的平均偏差是大约6.59%。在热入口区域的入口效果被讨论。在雷纳兹数字的一样的范围，压力落下和磨擦系数被发现比常规关联预言的那些更加高。磨擦因素和雷纳兹数字的产品也高是一个常数，而是大部分比常规。

简介：Chlorofluorocarbons(CFCs)orhydrochlorofluorocarbons(HCFCs)areasmainrefrigerantsusedintraditionalrefrigerationsystemsdrivenbyelectricityfromburningfossilfuels,whichisregardedasoneofthemajorreasonsforozonedepletion(man-maderefrigerantsemission)andglobalwarming(CO2emission).Sopeoplepaymoreandmoreattentiontonaturalrefrigerantsandenergysavingtechnologies.AninnovativesystemcombiningCO2transcriticalcyclewithejectorcycleisproposedinthispaper.TheCO2compressionsub-cycleispoweredbyelectricitywiththecharacteristicsofrelativelyhightemperatureinthegascooler(definedasanintercoolerbytheproposedsystem).Inordertorecoverthewasteheat,anejectorsub-cycleoperatingwiththenaturalrefrigerants(NH3,H2O)isemployed.Thetwosub-cyclesareconnectedbyanintercooler.Thiscombinedcyclejoinstheadvantagesofthetwocyclestogetherandeliminatesthedisadvantages.TheinfluencesoftheevaporationtemperatureinCO2compressionsub-cycle,theevaporationtemperatureintheejectorsub-cycle,thetemperatureintheintercoolerandthecondensationtemperatureintheproposedsystemperformancearediscussedtheoreticallyinthisstudy.Inaddition,someuniquefeaturesofthesystemarepresented.

简介：为了调查autoclaved的地震行为，给忍受负担的石工技术墙(AACLMW)，没有构造上的措施的一面控制块墙和五块与不同构造上的措施围的水泥充气了被测试在下面低颠倒的周期的装载它模仿了对中等地震力量低。有不同构造上的措施的AACLMW的地震行为以失败模式，hysteretic曲线，变丑能力和排水量韧性被学习并且与那相比没有构造上的措施。试验性的结果显示包括构造上的柱和水平具体脱衣的构造上的措施为改进AACLMW的地震行为是有效的。在这份报纸的学习以后能为进一步的分析和AACLMW的工程申请提供一个可靠试验性的基础。

简介：C.I.AcidRed73(AR73)wastewaterwastreatedbycross-flownanofiltrationcouplingelectro-catalyticoxidationusinganNF90membraneandaTi/SnO2–Sbanodepreparedviaelectrodeposition.ExperimentsconductedforstandardelectrochemicaldegradationofAR73studiedthereactionrateofremovingAR73usingtheTi/SnO2–Sbanode.Acomputationalfluiddynamics(CFD)modelwasdevelopedtopredictthepermeatefluxunderalaminarflowregime,includingtheeffectsofoperatingpressure,appliedpotential,initialconcentration,andcross-flowvelocityonthiscouplingprocess.Thevariationsofthemembranesurfaceconcentrationandpermeatefluxalongthelengthofthechannelwerequantified.Theexperimentalresultswerecomparedwiththosepredictedbythemodel,andtheyagreedwell.