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简介：Amajorroleofecologicalriskassessment(ERA)hasbeentoprovidescientificguidanceonwhetherafuturehumanactivitywillcauseecologicalharm,includingsuchactivitiesasreleaseofageneticallymodifiedorganism(GMO),exoticspecies,orchemicalpollutantintotheenvironment.Thisrequiresthedeterminationofthelikelihoodsthattheactivity:wouldcauseaharm,andwouldnotcauseaharm.Inthefirstcase,thefocusisondemonstratingthepresenceofaharmanddevelopingappropriatemanagementtomitigatesuchharm.Thisisusuallyevaluatedusingstandardhypothesisanalysis.Inthesecondcase,thefocusisondemonstratingtheabsenceofaharmandsupportingadecisionofbiosafety.WhilemostERAresearchershavefocusedonfindingpresenceofharm,andsomehavewronglyassociatedthelackofdetectionofharmwithbiosafety,anovelapproachinERAwouldbetofocusondemonstratingdirectlythesafetyoftheactivity.Although,someresearchershavesuggestedthatretrospectivepoweranalysiscanbeusedtoinferabsenceofharm,itactuallyprovidesinaccurateinformationaboutbiosafety.Adecisionofbiosafetycanonlybesupportedinastatisticallysoundmannerbyequivalencetests,describedhere.Usinga20%ecologicalequivalencestandardinGMOexamples,weillustratedtheuseofequivalencetestsfortwo-sampleswithnormalorbinomialdataandmulti-samplenormaldata,andprovidedaspreadsheetcalculatorforeach.Insixoftheeightexamples,theeffectsofCrytoxinsonanon-targetorganismwereequivalenttoacontrol,supportingadecisionofbiosafety.Theseexamplesalsoshowedthatdemonstrationofequivalencedoesnotrequirelargesamplesizes.Althoughmorerelevantecologicalequivalencestandardsshouldbedevelopedtoenableequivalenceteststobecomethemainmethodtosupportbiosafetydecisionmaking,weadvocatetheiruseforevaluatingbiosafetyfornon-targetorganismsbecauseoftheirdirectandaccurateinferenceregardingsafety.

简介：ThroughanalysisandnumericalcomputationofECMWF’sdiscreteschemeofhydrostaticequation(Baedeetal.1979),ithasbeenfoundthatinthecaseofequal△σthereexistsystematicerrorsinthescheme.TheerrorE(?)causedbytakingthearithmeticmeanofthegeopotentialheightsoftwoadjacenthalfa-levelsasthegeopotentialheightofthecor-respondingintegera-level,increaseswithheightandhasanunacceptablemaximuminthevicinityofthetopoftheat-mosphere;however,theerrorscausedbythetemperaturetreatmentaregenerallysmall.Ontheotherhand,ifanuneven△σ-schemeinwhichthelevelsintheupperandloweratmospherearedenserthanthoseinthemiddleatmosphere,isadopted,thenE(?)canbemuchreduced.However,iftheresolutionoftheoriginalequalArt-schemedoubles,thenE(?)canonlybefoundtobemuchreducedinthetroposphereandthatinthevicinityoftheatmospherictopisstillunacceptable.Twonumericalschemesforimprovementhavebeenpresented.OfthemoneisthesameastheECMWF’sscheme,butwithequal△lnσ,andtheotheristointegratetheequationbytheuseofTschebyscheffpolynomialsTandtoadoptthezerosofTNastheatmosphericlevelswhereNisthetotalnumberoflevels.Theresultsshowthatwithbothschemesthecomputationalerrorscanbemuchreduced,especiallythelatter,duetothefactthattheerrorsofthreestatisticaltypesaregenerallylessthantherootmeansquareerrorofthegeopotentialheightsreportedinTEMP.

简介：小粒的材料在工业并且在自然是无所不在的。为小紧张，有弹性塑料、发育不全的组成的关系广泛地在设计实践被使用，但是他们不是内在的物理的重要思考。在解释材料的物理的一个统一热力学框架下面，小粒的稳固的水动力学(GSH)是向描述小粒的材料，不是仅仅像固体，而且像液体的行为的延期。在这份报纸，GSH的基础简短被对待然后简化了在triaxial压缩分析quasistatic变丑。计算压力紧张关系和容量的紧张与试验性的结果相比。在GSH的主要参数的影响，特别他们的生气联合影响，被分析，他们的物理意思进一步被澄清。在参数被校准以后，处于典型压力状态的计算压力价值被发现在22%测试价值以内。同时，精力驱散在triaxial压缩期间被分析。上述结果支持并且部分确定GSH。

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简介：Inthispaper,westudyatwo-speciesperiodicBeddington-DeAngelispredator-preymodelwithdelayinatwo-patchenvironment,inwhichthepreyspeciescandispersebetweentwopatches,butthepredatorspeciescannotdisperse.Onthebasisofthecomparisontheoremofdifferentialequations,weestablishsufficientconditionsforthepermanenceandextinctionofthesystem.

简介：张代洲，唐孝炎，秦瑜，岩坂泰信，盖秀贞ＴｅｓｔｓｆｏｒｉｎｄｉｖｉｄｕａｌＳｕｌｆａｔｅ－ＣｏｎｔａｉｎｉｎｇＰａｒｔｉｃｌｅｓｉｎＵｒｂａｎＡｔｍｏｓｐｈｅｒｅｉｎＢｅｉｊｉｎｇ￥ＺｈａｎｇＤａｉｚｈｏｕ；ＴａｎｇＸｉａｏｙａｎ（Ｃｅｎｔｅｒｆｏｒ...

简介：Asystematicalsimulationhasbeencarriedoutontheindentationcreeptestonparticle-reinforcedcomposites.Thedeformation,failuremechanismsandlifeareanalyzedbythreereasonablemodels.Thefollowingfivefactorshavebeenconsideredsimultaneously:creeppropertyoftheparticle,creeppropertyofthematrix,theshapeoftheparticle,thevolumefractionoftheparticleandthesize(relativesizetotheparticle)oftheindentationindenter.Forallthecases,thepowerlawrespectingtotheappliedstresscanbeusedtomodelthesteadyindentationcreepdepthrateoftheindenter,andthedetailexpressionshavebeenpresented.Thecomputersimulationprecisionisanalyzedbythetwo-phasemodelandthethree-phasemodel.Twoplacesofthestressconcentrationarefoundinthecomposites.Oneisaheadoftheindentationindenter,wherethehighstressstateisdeducedbytheedgeoftheindenterandwilldecreaserapidlyneartoasteadyvaluewiththecreeptime.Theotheroneisattheinterface,wherethehighstressstateisdeducedbythemisfitofmaterialpropertiesbetweentheparticlesandmatrix.Ithasbeenfoundthatthecreepdissipationenergydensityotherthanastressparametercanbeusedtobethecriteriontomodelthedebondingoftheinterfaces.Withthecriterionofthecriticalcreepdissipationenergydensity,apowerlawtotheappliedstresswithnegativeexponentcanbeusedtomodelthefailurelifededucedbythedebondingofinterfaces.Theinfluencesoftheshapeoftheparticlesandthematchingofcreeppropertiesofparticleandmatrixcanbediscussedforthefailure.Withacrackmodel,thefurthergrowthofinterfacecrackisanalyzed,andsomeimportantexperimentalphenomenacanbepredicted.Thefailuremechanismwhichtheparticlewillbepunchedintomatrixhasbeenalsodiscussed.Thecriticaldiflerencesbetweenthecreeppropertiesoftheparticlesandmatrixhavebeencalculated,afteraparameterhasbeendefined.Intheviewofcompetitionoffailure

简介：ＳｔａｔｉｓｔｉｃａｌｔｅｓｔｓｏｆｒｅｃｅｎｔｐｌａｔｅｔｅｃｔｏｎｉｃｕｎｉｔｓｂｙｕｓｉｎｇｇｅｏｄｅｔｉｃｄａｔａＺＨＩＰＩＮＧＬＵ１）（吕志平）ＸＩＡＮＢＩＮＧＷＵ２）（吴显兵）ＣＨＡＯＺＨＡＮＧ１）（张超）１）ＺｈｅｎｇｚｈｏｕＩｎ...

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简介：如果在上游的边界条件仅仅基于事件波浪被规定，时间依赖者当物理或假的反映的波浪变得重要时，数字模型不能有效地模仿波浪地。这份报纸小心地描述一条途径到指定条件与集合海绵层相结合向事件边界吸收反映的波浪的事件波浪边界。把数字模型合并了到一个时间依赖者，谁的管理方程是Boussinesq类型，途径的有效性详细被学习。一般边界调节，描述下面波浪边界条件也被概括到随机的波浪的盒子。数字模特儿详细被检查。测试用例包括常规的正常一个维的事件和二维的倾斜的事件常规波浪。计算结果证明现在的途径在向事件波浪边界抑制反映的波浪上是有效的。

简介：IN690superalloy的热变丑行为在12731473K的一个温度范围和0.0110s的一个紧张率范围被描绘?1使用的单轴的压缩测试在上处理退火的材料。在流动应力和有效紧张，有效紧张率以及变丑温度之间的组成的关系被学习。流动显著地与IN690superalloy增加的变丑温度强调还原剂，这能被结束。而，当紧张率从0.1s增加时，有流动应力的重要增加?1～10s?1。基于夸张正弦的Arrhenius类型方程，就紧张的赔偿而言的一个组成的方程被开发。当变丑紧张增加，激活精力和材料常数(Q，n和lnA)减少。紧张依赖者术语成功地通过一个四次的方程在组成的方程被合并。在试验性的数据和预言的结果之间的一个好协议被完成了，显示建议组成的方程和材料常数是的determing的方法对模型合适IN690superalloy的高温度变丑行为。

简介：AnA.D.I.Galerkinschemeforthree-dimensionalnonlinearparabolicintegro-differen-tialequationisstudied.Byusingalternating-direction,thethree-dimensionalproblemisreducedtoafamilyofsinglespacevariableproblems,thecalculationissimplified;byusingalocalapproxima-tionofthecoefficientsbasedonpatchesoffiniteelements,thecoefficientmatrixisupdatedateachtimestep;byusingRitz-Volterraprojection,integrationbypartandothertechniques,theinfluencecomingfromtheintegraltermistreated;byusinginductivehypothesisreasoning,thedifficultycomingfromthenonlinearityistreated.ForbothGalerkinandA.D.I.Galerkinschemesthecon-vergencepropertiesarerigorouslydemonstrated,theoptimalH~1-normandL~2-normestimatesareobtained.

简介：患者女，76岁。15个月前在我院行经腹食管裂孔旁疝手术复位、疝成形及修补术，术后上腹不适、返酸及绞痛消失。近十几天来感上腹痛、返酸，平卧时加重，站立或坐位时症状减轻，夜间不能平卧睡眠。X线透视及钡餐透视发现：膈上可见胃囊。诊断为复发性食管裂孔旁疝。于2007年3月21日在全麻下行BardCruraSoftPatch，经腹行食管左侧裂隙修补。

简介：AbstractFor the detection of steatosis, quantitative ultrasound imaging techniques have achieved great progress in past years. Magnetic resonance imaging proton density fat fraction is currently the most accurate test to detect hepatic steatosis. Some blood biomarkers correlate with non-alcoholic steatohepatitis, but the accuracy is modest. Regarding liver fibrosis, liver stiffness measurement by transient elastography (TE) has high accuracy and is widely used across the world. Magnetic resonance elastography is marginally better than TE but is limited by its cost and availability. Several blood biomarkers of fibrosis have been used in clinical trials and hold promise for selecting patients for treatment and monitoring treatment response. This article reviews new developments in the non-invasive assessment of non-alcoholic fatty liver disease (NAFLD). Accumulating evidence suggests that various non-invasive tests can be used to diagnose NAFLD, assess its severity, and predict the prognosis. Further studies are needed to determine the role of the tests as monitoring tools. We cannot overemphasize the importance of context in selecting appropriate tests.

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简介：Electricalemission(EM)signals,whicharegeneratedfromtheconcretespecimensunderthree-pointbendingtests,wereconducted.Itisshownthatelectricalemissionphenomenaarerelatedtocrackingofthespecimens,cohesivefailure,contact-separationetc.Thesimultaneousappearanceofelectricemissionsignalsandvisiblecracksduringtheflexureloadingofbeamswasalsoobserved.

简介：Theprojectforcatalyticconversionofbiomassinto1,2-propanedioljointlydevelopedbytheCASDalianInstituteofChemicalPhysics(DICP)hasmadegreatstridesaftersuccessfulcommissioningofa100t/apilotplantatthefirstattemptwiththeconversionrateandproductselectivitybothreachingover90%.