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简介：本期“作文点评”栏目继续为大家点评在2008年全国中学生英语作文大赛中获得一等奖的优秀作文。本文小作者针对2008年全国中学生英语作文大赛备选题目（一）的所给材料发表了自己的见解和意见，呼吁大家加强环保意识。一起来看看小作者是如何行文及一线教师的点评吧!“

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简介：Thispaperdealswithamethodologyforsinglegatelocationoptimizationforplasticinjectionmold.Theobjectiveofthegateoptimizationistominimizethewarpageofinjectionmoldedparts,becausewarpageisacrucialqualityissueformostinjectionmoldedpartswhileitisinfluencedgreatlybythegatelocation.Featurewarpageisdefinedastheratioofmaximumdisplacementonthefeaturesurfacetotheprojectedlengthofthefeaturesurfacetodescribepartwarpage.Theoptimizationiscombinedwiththenumericalsimulationtechnologytofindtheoptimalgatelocation,inwhichthesimulatedannealingalgorithmisusedtosearchfortheoptimum.Finally,anexampleisdiscussedinthepaperanditcanbeconcludedthattheproposedmethodiseffective.

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简介：Amechanismofplasticflowlocalizationinductilematternearmi-crovoidsisstudied.Thevoidswiththesize-scaleofmicromillimeterexistinsheetspecimensundertensileloading,andtheplasticstrainfieldaroundvoidsisobtainedbydigitalimageprocessingofdeformedgrids.Thesizegrowthofthemicrovoids,thespacingchangeoftheneighboringvoids,andthedevelopmentofshearbandsintheligamentbetweenthevoids,arepresentedbyexperimentalresultsaccompaniedwiththeplasticstraindistribution,thatgivesgoodinterpretationtotheprocessofvoidgrowthandcoalescencewiththeflowlocalizationintheligaments.

简介：Thesteelreinforcedplasticpipeisakindofgreenenvironmentalprotectionpipelineswithdouble-sidescorrosionresistingandbetterwithstandingtomediumworkingpressure.Thestructureandtechnicalprocessofthispipearedescribedbrieflyinthispaper,andthefiniteelementanalysishasbeendoneforthesakeofunderstandingthedistributionsofstressanddisplacementinsidethispipeunderhydrostaticpressure.Theanalysisresultsareveryimportantforsafetyapplicationofthesteelreinforcedplasticpipe.

简介：-Thispaperadoptsapproximateformulasforresidualstressescausedbycoldbendingforplateswithstress-straincurveforma=Kn.Atypicaldistributionofthelongitudinalresidualstressduetoweldingisalsoassumed.Theeffectsofresidualstressduetocoldbendingandweldingonplasticbucklingofaxiallycompressedcylindricalshellsarestudiedbythefiniteelementmethod.

简介：1ScopeThisstandardspecifiesthedefinition,classification,technicalrequirements,testmethods,inspectionrules,packing,marking,transportationandqualitycertificateofcorundumblockcontainingplasticphase.Thisstandardismainlyapplicabletotheblocksforlayinginnerliningofhearthandbottomofblastfurnace.

简介：Numericalsimulationofinjectionmoldinghavehadsuccessinpredictingthebehaviorofpolymermeltinextremelycomplicatedgeometries.Mostofthecurrentnumericalsolutionsarebasedonfinite-element/finite-difference/boundary-element/volume-controlmethodsandthesurfacemodel.ThispaperdiscussesthedevelopmentofanintegratedCAEsystemforinjectionmoldingindetail,andpresentsthemathematicsfornumericalsimulationoffilling,packing,cooling,stressandwarpageininjectionmolding.ThedevelopedsystemnamedasHsCAE3Disintroducedattheend.

简介：Flammabilitypropertiesofcompositesofwoodfiberandrecycledplasticwereevaluatedbytheconecalorimeterandoxygenindexchamber.Resultswereshownasfollows:1)Wood-PVCcompositeshowedworsethermalstabilityontimetoignition(TTI)andmeanheatreleaserate(MHRR),butbetterperformanceonheatreleaserate(HRR)andmeanefficientheatofcombustion(MEHC);wood-PPcompositehadbetterthermalstabilityproperties,butwasworseonotherfireperformance;2)Comparedwithwood-PVCcomposi...

简介：Forthepurposeofreducingthevolumetricshrinkageandvolumetricshrinkagevariation,theprocessininjectionmoldingofasphericplasticlenswassimulated,andseveralprocessparameterswhichincludeholdingpressure,melttemperature,moldtemperature,filltime,holdingpressuretimeandcoolingtimewereoptimizedbyusinganorthogonalexperimentaldesignmethod.Finally,theoptimumprocessparametersandtheinfluencedegreeofprocessparametersontheaveragevolumetricshrinkageandthevolumetricshrinkagevariationareobtained.

简介：纸论述elasto塑料的细胞的自动机(EPCA)的前进和应用，为设计的岩石力学和岩石的一个模拟器。EPCA的最重要的特征躺在它处理岩石的非线性的行为的下面顶方法。理论，基本想法和联系开发包括细胞的自动机的定义，异构的材料模型，组成的关系，失败标准，收益以后的弄软计划，联合过程的thermo-hydro-mechanical，被描述。应用程序被介绍显示EPCA的能力为岩石失败进程，液体流动，热转移，和联合thermo-hydro-mechanical(THM)进程等等建模。

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简介：EffectsoftheorientationandapexangleonthesettlingvelocityofconicalparticlesinBinghamplas-ticfluidsarenumericallyinvestigatedoveraReynoldsnumberrangeof1≤Re≤100,Binghamnumberrangeof0≤Bn≤100,andconeanglerangeof20≤α≤150°.Governingequations(ofcontinuityandmomentum)aresolvednumericallyusingthefiniteelementmethodtoobtainvelocityandpressurefieldsthatarepostprocessedtoobtainvaluesofthedragcoefficien.Futthermore,theeffectofconeori-entationontheflowfieldisvisualizedandexploredintermsofstreamlinecontoursandthemorphologyofyielded/unyieldedregions.Finally,theobtainedvaluesofdragarecorrelatedviaasimplepredictiveexpressionintermsofthemodifiedReynoldsnumber.Theeffectoftheconeangleondragisfoundtobemoderatebecausethedragforceactingonthelateralsurfaceisasmallfractionoftheoveralldrag.

简介：Byusingthelogarithmicstrain,thefinitedeformationplastictheory,correspondingtotheinfinitesimalplastictheory,isestablishedsuccessively.Theplasticconsistentalgorithmwithfirstorderaccuracyforthefiniteelementmethod(FEM)isdeveloped.Numericalexamplesarepresentedtoillustratethevalidityofthetheoryandeffectivenessofthealgorithm.

简介：Aplasticdeformationzonenearascrewdislocationistreatedasanequivalenttrans-formationinclusionbymeansoftheEshelbyinclusiontheory.Aclosed-formsolutionfordeter-miningtheinteractionbetweenascrewdislocationandaplasticallydeformedzoneofanarbitraryshapeisobtainedbyusingthesolutionbetweenadislocationandanequivalenttransformationinclusion.

简介：动态反应上的学习，和特别使硬的盘子的非线性的动态反应由他们的断绝和不同类是复杂的。有限元素方法(女性)并且有限长带方法通常在他们的分析被采用。尽管许多有用结论被获得了，计算费用是庞大的。基于一些假设，有大偏转的夹钳的使硬的盘子的动态塑料反应被一个单身地对称的横梁模型理论上此处调查。第一，塑料绳必须满足的偏转条件被线性化的时刻轴的力量相互作用曲线为单身地对称的生气的节和联系塑料流动规则获得。第二，在不同负担紧张下面的横梁的可能的运动机制详细被分析。为有塑料变丑的结构，一个简化方法然后被给任意的影响负担能被矩形的脉搏相等地代替。最后，证实建议方法的有效性，有四个充分夹钳的边的一个单程的使硬的盘子的动态塑料反应被计算。理论结果在对那些的好同意女性。它显示现在的计算模型安逸、可行，并且负担的相等的替换几乎没在最后的偏转上有影响。

简介：AsanewproductinventedbytheResearchInstituteofWoodIndustry,no-formaldehydewood-plasticcompositeplywoodistheharvestofthecross-studyonwood-plasticcompositeandplywoodindustry.Ithasnoformaldehydeemission,withanexcellentenvironment-friendlyperformanceandagoodbondingquality.Thispaperanalysesthestrongpointsandmarketofthiswood-plasticcompositeplywood.

简介：Theload-bearingcapacitiesofduclilecompositematerialsandstructuresarestudiedbymeansofacombinedmicro/macromechanicsapproach.Firstly,onthemicroscopicscale,theaimistogetthemacroscopicstrengthdomainsbymeansofthehomogenizationtheoryofmicromechanics.Arepresentativevolumeelement(RVE)isselectedtoreflectthemicrostructuresofthecompositematerials.Byintroducingthehomogenizationtheoryintothekinematiclimittheoremofplasticlimitanalysis,anoptimizationformaltodirectlycalculatethelimitloadsoftheRVEisobtained.Andthemacroscopicyieldcriterioncanbedeter-minedaccordingtotherelationbetweenmacroscopicandmicroscopicfields.Secondly,onthemacroscopicscale,byintroducingtheHill’syieldcriterionintothekinematiclimittheorem,thelimitloadsoforthotropicstructuressuchasunidirectionalfiber-reinforcedcompositestructuresareworkedout.Thefiniteelementmodelingofthekinematiclimitanalysisisdeducedintoanonlinearmathematicalprogrammingwithequality-constraintconditionsthatcanbesolvedbymeansofadirectiterativealgorithm.Finally,someexamplesareillustratedtoshowtheapplicationofthepresentapproach.