学科分类
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46 个结果
  • 简介:Fewotherpolicyzonesareascomplexastheissueofclimatechange.Ifthemorepessimisticprojectionsofclimatechangedoomarecorrect,thenthefailuretoaddresstheissueislikelytobecatastrophicandirreversible.TheInter-governmentalPanelonClimateChangehaspredictedthepotentialextinctionofmanyspeciesandthattheexistenceofsmall-islandandothervulnerablecountrieswillbethreatenedifbusiness-as-usualgreenhousegasemissionscontinue.Climatechangeisatransboundaryproblemandrequiresunprecedentedlevelsofcooperationbetweenstatesandseriousandsustainedresponsesfrommajoremitters.However,thegrowingdemandandconsumptionofnaturalresourcesforcontinuedenergysecurityandcornucopianeconomicgrowthhaveunderminedtheoutcomesofinternationalclimatechangenegotiations.Itisarguedherethatthereisastrongconnectionbetweenthemajoremitters’positionsatUnitedNations’climatetalks,theirpossessions,dependenceandconsumptionofnaturalresources,andthecontinuedunderminingofinternationalclimatechangepolicyforunsustainablegrowth.ThispaperassessestheresourcepoliticsoftheUS,China,India,Canada,Russia,andSaudiArabiaandtheirpositionsatclimatetalkstoshowthelinkbetweenlackofclimatechangepolicyprogressandthepositionsofthesemainplayers.

  • 标签: RESOURCES climate change policy UNITED STATES
  • 简介:Thispaperhasorganizedandsummarizedtheeconomicanalysisonclimatechangefromfiveangles,namely,connotationofdiscountrate,identificationofanddisputeaboutdiscountrate,discountingway,impactofthediscountrate,andtheintegratedevaluationmodelofclimatechangeimpactandthediscountevaluation.Astheclimatechangeeconomicanalysisshows,thereisamajordisputeaboutdiscountratebetweenthemarketschoolandtheethicschool.Rateofdiscountlargelyrelatestothepresentvalueofpotentiallossattributabletoclimatechange,andtheninfluencestheselectionofpoliciesforadaptingandslowingdownclimatechange.Inthepast,theconstantindexdiscountwasadoptedasthemainway.Butwiththefullunderstandingofdiscountrate,theuncertaintyoflossattributabletoclimatechangehasbeenconsideredinthediscount.

  • 标签: CLIMATE CHANGE ECONOMICS DISCOUNT rate
  • 简介:当前transrectal指导超声的前列腺活体检视(TRUS-Bx)是最普通的urological过程之一,在经历TRUS-Bx的病人之中在欧洲和统一States.1每年与超过100万表现了,约三分之一个将收到前列腺癌症(PCa)的诊断,当三分之二在起始的活体检视上收到否定结果时。否定活体检视病人在1年维持12%的重复活体检视的估计的风险并且38%在5years.2标准TRUS-Bx是可能的系统地错过重要肿瘤,特别地在gland.3的前面、顶端的部分,在下一十年的泌尿科医师的一个关键目的是增加过程的精确性并且避免不恰当的活体检视的使用。

  • 标签: 前列腺癌 活检 穿刺 发病率 呼叫 心理
  • 简介:Experimentsshowthatsiltsandsiltysoilsexhibitcontractionfollowedbydilationduringshearingandtheslopeoffailurelinedecreasesatlargestrains,termedasphasetransformationbehaviour.Thispaperistodevelopanewmicromechanicalstress-strainmodelthataccountsforthephasetransformationbehaviourbyexplicitlyemployingthephasetransformationlineanditsrelatedfrictionangles.Theoverallstrainincludesplasticslidingandplasticcompressionamonggrains.Theinternal-frictionangleatthephasetransformationstateandthevoidstatevariableareemployedtodescribethephasetransformationbehaviour.ThemodelisexaminedbysimulatingundrainedanddrainedtriaxialcompressiontestsperformedonPiteasilts.Thelocalstress-strainbehaviourforcontactplanesisalsoinvestigated.更多还原

  • 标签: 相变行为 力学建模 三轴压缩试验 细观 应力应变特性 内摩擦角
  • 简介:Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.

  • 标签: 相场模型 规模效应 模型模拟 骨折 尺寸效应 演化方程
  • 简介:西藏的高原是在中国的最重要的生态的障碍之一。解决统治在地区性的植被和气候变化之间的协会的内部关系和动力学是重要的理解并且保护地区性的生态系统。从2001~2010基于植被,温度和西藏的高原的降水数据,我们在过去的10年分析植被盖子的空间、时间的变化并且用实验直角的功能和单个值分解讨论植被反应到气候变化。我们的结果揭示下列:(1)植被盖子逐渐地从东南减少到西藏的高原的西北;(2)植被盖子在过去的10年在西藏的高原上增加了,主要在中央、东方的地区;并且(3)一种重要积极关系在在中央、南部的地区在全部区域并且与降水种季节和温度期间在植被盖子之间被建议。

  • 标签: 植被覆盖 青藏高原 气候变化 时空变化 经验正交函数 植被盖度
  • 简介:<正>1IntroductionAlkalinelakesarewidelydistributedintheareaoftheQinghai-TibetPlateau.Mostofthesaltlakesarefamousfortheirhighconcentrationoflithium,potassium,magnesium,boron(Ma,2000).Inrecentyears,asanewenergymaterial,lithiumanditscompoundsarewidelyusedinthenewarea,suchasaerospaceindustry,nuclear

  • 标签: LITHIUM magnesium BORON Plateau POTASSIUM aerospace
  • 简介:Therandomphaseerrorsoftheopticalcarriersarediscussedandcontrolledforpassivemillimeter-wavesparseaperture(PMMWSA)upconversionimaging.Atwo-channelmodelissetupforanalyzingcharacteristicsofthephaseerrors,andanactiveopticalcontroltechniquebasedonstochasticparallelgradientdecentalgorithm(SPGDcontroller)isproposedtocalibratethephaseerrors.TodemonstratethefeasibilityoftheSPGDcontroller,simulationsareperformedandanexperimentalsystemwithatwo-channelfiberarrayissetup.SimulationandexperimentresultsshowthattheSPGDcontrollercaneffectivelyandrapidlycompensatethephaseerrorsoftheopticalcarrier,andtheaccuracyofthephasecontrolissufficientforimagingsystems.

  • 标签: 相位控制 稀疏孔径 毫米波 成像 相位误差 光学
  • 简介:Theinfluencingfactorsforliquidphasecatalyticoxidationofminegastomethanol(informofCH3COOCH3)arestudiedusingtheself-establishedexperimentalapparatus.TheresultsshowthatCH3COOCH3(targetproduct)isobtainedbyusingCH3COOHasreactionsolvent,andtheyieldoftargetproductincreaseswiththeincreasingofreactiontemperature,gaspressureandreactiontime.Intheminegas-Pd(OAc)2-CH3COOHsystem,theyieldofCH3COOCH3increaseswiththeincreasingofadditionofPd(OAc)2whichisredoxcatalystforminegasconversion.TheyieldofCH3COOCH3willbegreatlyimprovedbycompositeadditionaloxidantwhichisobtainedbyequimolarmixofp-benzoquinonewithNO2.

  • 标签: 液相催化氧化 矿井瓦斯 影响因素 甲醇 还原催化剂 实验装置
  • 简介:阶段地水晶(陆军)模型被用来模仿premelting脱臼运动对称当系统温度在时,在紧张行动下面倾斜谷物边界(STGB)远非,到融化的融化的点和结束分别地指。结果证明当premelting温度被接近到,本地premelting发生包围脱臼从在温度下面。STGB的premelting脱臼能在紧张行动下面滑行,并且premelting区域是为脱臼滑行的一个同伴。STGB腐烂的过程以二个高温度条件是很类似的。当premelting介绍,它减少为脱臼的滑行抵抗并且导致脱臼的一个更快的运动,并且也在STGB的腐烂过程期间引起系统的更多的精力减小。尽管有把紧张用于这些,premelting在STGB的整个腐烂过程取样,premelting脱臼区域显然不发展并且延长。这显示外部紧张行动不在高温度支持premelting,并且不能导致更多的premelting脱臼,它能在脱臼展览附近被欠到premelting阶段像液体的性质并且到容易滑行并且放松紧张精力的premelting脱臼;这与实验和分子的动力学的结果一致。

  • 标签: 位错反应 晶界 晶体 相场 温度条件 移动
  • 简介:通过magnetostratigraphy的全面研究和在东北西藏的高原的几盆的sedimentology,我们表明学习区域主要经历了六构造高举在约52妈,的阶段34-30妈,24-20妈,16-12妈,8-6妈,和3.6-2.6妈。从Qaidam,Linxia,Xining,和西方Jiuquan盆的花粉集合的全面分析证明东北西藏的高原在植被类型和气候经历了六个主要变化:为温暖潮湿的森林植被的50-40妈,为温暖干旱、适度干旱的森林大草原植被的40-23妈,为温暖潮湿、适度潮湿的森林植被的23-18.6妈,为温暖潮湿、凉爽潮湿的森林大草原植被的18.6-8.5妈,为适度的亚humid无树平原大草原植被的8.6-5妈,并且为寒冷干旱的大草原植被的5-1.8妈。全面比较构造高举从沉积记录,从花粉推断的气候的变化,和全球气候变化推断的事件在东北西藏的高原显示出那在在低高度的Paleogene的气候被全球气候变化主要控制,当在晚第三纪,有山和盆的高高度风景的间隔是更多,这由高度和形态学控制了时。

  • 标签: 全球气候变化 青藏高原 构造隆升 东北部 中新生代 沉积物
  • 简介:Climatechangeisexpectedtobeamajordrivingforceoflandscapeinthecomingdecades.Itwillhaveamultitudeofpotentialimpactsthatvaryinintensityandeffectaccordingtoregionandsector.Inthecontextofglobalwarming,theclimateofChinahaschangedsignificantlyintherecent100years.ThereasonforclimatechangeinChinaismainlyduetoirrationallandusecausedbyhumanactivities,whichchieflyresultsintherapidindustrializationandurbanizationprocess.Basedonanassessmentmodel,thisresearchrepresentsapictureoftheimpactsofclimatechangeinsixdistrictsofHangzhouregion.Theaimofthispaperistoconclude,ontheonehand,someofHangzhousensitivitiesinrelationtotheprimaryeffectsofclimatechange.Ontheotherhand,areflectionismadeonamethodologytoformulatepreconditionsonascientificbasisforfurtherresearchbydesignofintegratedadaptationoptionsforthefuturespatialdevelopmentsinfunctiontoupgradeHangzhouresilienceinrelationtoclimatechangechallenges.

  • 标签: CLIMATE CHANGE IMPACT Hangzhou
  • 简介:Forrecentyears,runoffgenerationandhydrologicalprocessesinHailiutuRiverbasinhavebeengreatlychangedbyclimatechangeandhumanactivity,especiallywaterandsoilconservationconstruction.Inthisstudy,thetrendsinprecipitation,evapotranspiration(ET)andriverrunoffaswellastheeffectsofprecipitationchangeandhumanactivityonrunoffvariationhavebeenstudied.Theresultsshowedthatduring1960-2000,annualprecipitationandriverrunoff,monthlyprecipitationandETinSeptemberandOctoberaswellasmonthlyrunoffinallmonthsshowedasignificantdecrease.Inaddition,peakflowandbaseflowhadalargedecrease.Underthejointinfluenceofprecipitationchangeandhumanactivity,themeanannualrunoffdecreasedby35millionm3fromthebaselineperiod(1960-1985)tothechangeperiod(1986-2000),whichaccountedfor60.9%and39.1%ofthetotalrunoffdecrease,respectively.Precipitationchangeplayedaprimaryroleinthedecreaseofannualrunoffwhereashumanactivity,particularlywaterandsoilconservationconstruction,alsohadremarkableimpactsonrunoffvariation.

  • 标签: RUNOFF VARIATION PRECIPITATION CHANGE human activi
  • 简介:DearSir,IamDr.Yin-HungChangfromtheDepartmentofOtolaryngology,TaipeiTzuChiHospital,theBuddhistTzuChiMedicalFoundation.Iwouldliketopresentacaseofinvertedpapillomawithcarcinomachangeoflacrimaldrainageapparatusandnasalcavitythathadbeensuccessfullytreatedbyendoscopicsurgery.Lacrimaldrainageapparatustumorsarerarebutimportant

  • 标签:
  • 简介:ThepresentstudyinvestigatedtheinfluenceofhightemperatureoxidationandreductionpretreatmentsontheleachingrateofPanzhihuailmenite.Theas-pretreatedilmenitewasleachedwith20%HClat105℃.Theleachingprocesswascontrolledbythephasesandmicrostructuresthatevolvedduringthepretreatmentprocesses.Theleachingkineticsofpurehematite,ilmeniteandpseudobrookitewerecharacterizedtoclarifythephaseeffectontheiron-leachingrate;therateofironleachingoccursinthefollowingorderintheHClsolution:hematite(ferriciron)>ilmenite(ferrousiron)>>pseudobrookite(ferriciron).Therefore,theoften-citednotionthatferrousirondissolvesfasterinHClsolutionsthanferricironwhenexplainingthepretreatmenteffectsisinaccurate.Moreover,theoxidationpretreatment(at600-1000℃for4h)cannotdestroythedensestructureofthePanzhihuailmenite.Therefore,theinfluenceexertedbytheoxidationontheleachingprocessisprimarilydeterminedbythephasechange;oxidationat600and700℃slightlyincreasedtherateofironleachingbecausetheilmenitewastransformedintohematite,whiletheoxidationat900-1000℃significantlyreducedtherateofironleachingbecauseapseudobrookitephaseformed.Thereductioneffectwassubsequentlyinvestigated;theas-oxidizedilmenitewasreducedunderH2at750℃for30min.Thereductionsignificantlyacceleratedtherateofsubsequentironleachingsuchthatnearlyalloftheironhaddissolvedafterleachingfor2hin20%HClat105℃.Thisenhancediron-leachingrateismainlyattributedtothecracksandholesthatformedduringthereductionprocess.

  • 标签: 预处理过程 钛铁矿 盐酸浸出 微观结构 攀枝花 HCL溶液
  • 简介:Thephasetransformationcharacteristicsofahigh-strengthTRIP-aidedmultiphasecold-rolledsteelduringcontinuousheatingatdifferentcoolingrateswerestudiedbymeansofdilatometry,andthecriticaltemperatureswerealsodetermined.Thesampleswerefullyaustenitizedat1050℃andthencooledatdifferentcoolingratesrangingfrom0.5℃/sto100℃/s.Thecontinuouscoolingtransformation(CCT)curveswereobtainedfortheexperimentalsteel.Theexperimentalresultsshowedthatahighcoolingratedepressedtheformationofferriteandpearliteandpromotedtheformationofbainiteandmartensite,leadingtoahigherhardness.Alargeamountofmartensiteinhigh-strengthTRIP-aidedmultiphasecold-rolledsteelcanbeobtainedatcoolingratesinexcessof50℃/s.Theexperimentalresultsprovideguidelinesforcoolingcontrolandheattreatmentinrealsteelproduction.

  • 标签: 冷却过程 相变特性 多相钢 跳闸 连续冷却转变 TRIP
  • 简介:Duetotheexistenceofspatialwalk-offand/orgroup-velocitymismatcheffects,pump-to-signalphasetransferbecomesinevitableduringparametricamplification.Weexperimentallydemonstratethatinhybridseededopticalparametricamplifiers(OPAs)thatincludetwoOPAstagesseededbythesignalandidlerwaves,respectively,thephaseoftheoutputsignalcanberestoredtoitsinitialvalue,althoughtherearespatialandtemporalphasefluctuationsonthepumpsource.Thismethodsignificantlyrelaxestherequirementforhighpumpbeamquality,whichisalwaysverystringentinparametricamplificationsystems.Withtheintroductionofthisschemeintobirefringentphase-matchingOPAsorchirped-pulseOPAs,itshouldbepromisingtoachieveintensefemtosecondlaserpulsesthatareclosetothediffractionlimitinspaceandultra-highcontrastintime,simultaneously.

  • 标签: hybrid SEEDING PARAMETRIC AMPLIFIER pump-to-signal phase