简介：IEEE802.15.4protocolisproposedtomeetthelowlatencyandenergyconsumptionneedsinlow-ratewirelessapplications,however,fewanalyticalmodelsaretractableenoughforcomprehensiveevaluationoftheprotocol.ToevaluatetheIEEE802.15.4slottedCSMA/CAchannelaccessmechanisminthispaper,weproposeapracticalandaccuratediscreteMarkovchainmodel,whichcandynamicallyrepresentdifferentnetworkloads.Bycomputingthesteady-statedistributionprobabilityoftheMarkovchain,weobtainanevaluationformulaforthroughput,energyconsumption,andaccesslatency.Thenwefurtheranalyzetheparametersthatinfluenceperformanceincludingpacketarrivalrate,initialbackoffexponentandmaximumbackoffnumber.Finally,NS2simulatorhasbeenusedtoevaluatetheperformanceofthe802.15.4CSMA/CAmechanismunderdifferentscenariosandtovalidatetheaccuracyoftheproposedmodel.

简介：Basedonresearchesmadebytheauthorinrecentyears,discussionismadeofthequasi-40-dayoscillation(QDO)natureanditscharacteristicpropagation,withemphasisontheSouthernHemispheremill-latitudequasi-periodiccoldairforcingonthetropicalatmospherequasi-40-dayoscillationalongwithitseffectupontheNorthernHemispheresummermonsoon.Itisproposedthattheinteractionbetween,orlateralcouplingof,meridionalcirculationsystemsmayserveasthemechanismoftheoscillationpropagationinameridionaldirection.

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简介：Hydrogenembrittlementisoneofthekeyissuesforthevanadiumalloysforfusionapplication.PreviousstudyhasshownthatV4TialloyhadbetterpropertiesagainsttheembrittlementthanV4Cr4TiandV4Ti3A1alloys.Itwasthoughtthatthebetterpropertywasbenefitedfromthesmallratioofitsyieldstrengthoveritsultimatetensilestrength.

简介：Thepaperanalysesredoxreactionsofan-tioxidantsSiandSiCeteatdifferentpositionsinthecourseofoxidationofcarbon-containingmaterials,Itispointedoutthatredoxreactionofantioxidantsinoxidized-zoneplaysaveryimportantpartinantioxidationofcarbon-con-tainingmaterials,ThereasonwhySiCcanmakecarbon-containingmaterialantioxideatthermodynamictemperaturehasbeenex-plained,Experimentprovesthatantioxidantsinoxidizedzonecanmakecarbon-containingmaterilsantioxidize.

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简介：Themultilayered7XXXseriesaluminumalloywasimpactedby7.62mmogivalprojectilesatvelocitiesrangingfrom787to851m·s~(-1).Thedeformedmicrostructureundervariousimpactingvelocitiesandfracturesurfacesofdifferentsectionswereinvestigatedatdifferentphysicalscalestodeterminetheprocessoffailure.Opticalmicroscopy(OM),electronback-scattereddiffraction(EBSD)andscanningelectronmicroscopy(SEM)wereusedintheinvestigation.Theresultsshowthatcraterisconstrainedinthe7B52frontlayerandtwotypesofadiabaticshearbandswhicharetransformedbandsanddeformedbandsanddifferenttypesofcracksareobserved.Spallfractureisthesignificantfailuremodeof7B52frontlayer,andtheresultingdelaminationleadstothepresenceofbendingtensilefractureinsteadoftheshearplugging.Theductile7A01layerbluntsanddeflectsthespallcracktips,preventingthetargetsfromfullspall,andinducesaconstraintof7A52rearlayer.Theleveloftheconstraintdeterminesdifferentfracturemodesof7A52layer,accountingfortheasymmetryofdamage.

简介：Comparedwithendpumpingfibercombiner,oneoftheadvantagesforsidepumpingcombineristheunlimitedpumpingpoints,whichmeansmulti-pointorcascadedsidepumpingcanberealized.However,thelossmechanismofthecascadedstructureisrarelydiscussed.Inthispaper,wepresentthenumericalandexperimentalinvestigationaboutthelossmechanismofatwo-stage-cascadedsidepumpingcombinerbasedontapered-fusedtechnique.Theinfluenceoflossmechanismonthecouplingefficiencyandthermalloadofthefibercoatingisanalyzedaccordingtosimulationsandexperimentswithdifferenttaperingratiosforthefirststage.Basedontheanalysis,acascadedcomponentwithtotalpumpcouplingefficiencyof96.4%handlingapumppowerof1088Wisachievedbyemploying1018nmfiberlaserasthepumpsource.Futureworktofurtherimprovetheperformanceofacascadedsidepumpingcombinerisdiscussedandprospected.

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简介：这篇文章描述在一个无线网孔网络分享系统的一个合作文件的一个新模型。作者的途径是开发基于机会主义的随机的线性网络编码分享机制的一个有效、合作的文件。在这机制以内，每个节点根据合作优先级播送它的包的随机的线性联合，它根据对它的邻居节点的节点可能的贡献以一种分布式的方式被计算。与这机制，一个节点越贡献其它，节点越有机会首先恢复全部文件。这里的兴趣的表演度量标准是：延期被送到直到在一个文件的所有包所有节点，和一种理想的包尺寸，由作者能得到最小的传播延期的使用。没有随机的线性网络编码，通过广泛的模拟，作者在一个无线网孔网络把他们的机制与当前的传播进程作比较。作者发现用他们的机制，节点能合作地与更少的传播时间分享全部文件并且没有随机的线性网络，比当前的传播进程推迟。

简介：陆地使用转变在社会经济的变化和革新驾驶的时间的某个时期上在某个区域的陆地使用形态学(主导的形态学和后退的形态学)指变化，并且它通常对应于社会经济的发展阶段的转变。在中国，农田和农村住房土地是陆地使用转变的二主要来源。这份报纸在中国分析农田和农村住房陆地转变的时间空间的联合特征，用高分辨率的LandsatTM(题目的Mapper)在2000和2008的数据，和从土地的部和中国的资源的数据。结果显示了那：(1)在20002008期间，农田的关联系数对农村住房土地变化是0.921，并且它证明农田的变化模式和农村住房土地是不协调的；(2)枪兵等级关联分析的结果证明那个农村住房陆地变化在农田和农村住房土地的相互的转变起了一个主要作用；并且(3)它出现一在20002008期间的在东南中国的在农田和农村住房陆地变化之间的高度的空间联合。一般来说，在中国的农田和农村住房陆地转变被社会经济、生物物理、经理的三维的开车因素在农村人口，农田和农村住房土地之中通过相互作用驾驶。然而，在中国的农田和农村住房陆地转变的时间空间的联合现象和机制大部分由于农村城市的开发的双轨道的结构。

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简介：Amodifiedsnap-throughmechanismisusedinanelectromagneticenergyharvestertoimproveitseffectiveness.Itmainlycomprisesthreespringsthatarecon-figuredsothatthepotentialenergyofthesystemhastwostableequilibriumpoints.Inparticular,thesmallvibrationbehavioroftheharvesteraroundoneoftheequilibriumsisofinterest.Amulti-scalemethod(MSM)isusedtoanalyzethefrequencyresponsecurve.Twosnap-throughmechanismsareconsidered.Onehasbothhorizontalandverti-calsprings.Theotherhasonlyhorizontalsprings.Thefrequencyresponsecurvesofthesetwoclassesarecomparedunderthesameexcitationandelectricloadingconditions.Thelatterexhibitsmorebendingofthefrequencyresponsecurvethantheformerone.Theresultsarealsovalidatedbysomenumericalwork.TheaveragedpowersubjecttotheGaussianwhitenoiseiscalculatednumerically,andtheresultsdemonstratethatbi-stableenergyharvestingwithonlyhorizontalspringscanoutperformthemechanismwithbothhorizontalandverticalspringsforthesamedistancebetweentwoequilibriums.

简介：Thetensile-shearfailurezoneofthelaminateddampingsteelsheetwasinvestigatedbyscanningelectronmicroscopyandX-rayphotoelectronspectroscopy.Itisfoundthatthereexistscohesivefailureinpolymersandwichandsub-boundaryfailurebetweenthesteelsheetandthepolymer.Thesub-boundarylayerisdominantlypolymermaterial.Thetensile-shearfailureofthelaminateddampingsteelsheetisaprocessduringwhichthecrazesform,growupandmergeintocracks.

简介：根据有房间膜的电的偶极子时刻的液体水晶模型，电的显微镜的机制和有房间膜的激光的相互作用的thermology效果被研究由电磁，量力学和量统计。我们在极化效果和激光房间膜相互作用的鈥渢e升起mperature效果鈥?上导出公式。理论研究的结果能解释一些实验。CLC数字R312这个工作被中国(号码第60068001a号码30360068)的国家自然科学基础支持，中国(No:2000A0021M和2006E0091M)和云南的科学基础的云南省的NSF师范大学。

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简介：Sm(Ⅲ）wasquantitativelyadsorbedbyaminomethylenephosphonicacidresin(APAR)inthemediumofpH=5.0,Thestaticallysaturatedsorptioncapacityis251mg/g.resin.Sm(Ⅲ）adsorbedonAPARcanbereductivelyelutedby2.0mol/LHCl.Thesorptionrateconstantisk298=1.35×10^-5s^-1.ThesorptionbehaviorofAPARforSm(Ⅲ）obeystheFreundlichisotherm.TheenthalpychangeΔH°ofsorptionis24.9kJ/mol.TheapparentactivationenergyisEa=11.7kJ/mol.ThesorptionmechanismshowsthatthenitrogenandoxygenatomsofthefunctionalgroupofAPARcoordinatedwithSm(Ⅲ）toformcoordinationbond.

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