简介:EffectofCe-Mg-Si(lightRE)andY-Mg-Si(heavyRE)nodulizersonthemicrostructuresandmechanicalpropertiesofheavysectionductileironwasinvestigatedtodevelopthematerialofspent-nuclear-fuelcontainers.Twoas-castsweretreatedbythesamequalitypercentageoflightREandheavyRE,respectively.Fourpositionswerechosentostandfordifferentsolidificationcoolingratesofspecimens.Thetensilestrength,elongationandimpacttoughnessofspecimenstreatedbyheavyREwereallhigherthanthoseofthespecimenstreatedbylightRE.Withthedecreaseofcoolingrate,themechanicalpropertiesoftwospecimensdecreased,andthefracturemorphologychangedfromductilefracturetobrittlefracture.TheimprovingeffectofmechanicalpropertiesbetweenheavyREandlightREwasobviousduetothebetteranti-degradationpropertyofheavyRE.Whilethesolidificationprocesslastedformorethan250min,theimprovingeffectwasnotobviousduetoseriousspheroidalizationdecaying.
简介:Sn-dopedTiO_2nanoparticleswithhighsurfaceareaof125.7m~2·g~(-1)aresynthesizedviaasimpleone-stephydrothermaimethodandexploredasthecathodecatalystsupportforprotonexchangemembranefuelcells.ThesynthesizedsupportmaterialsarestudiedbyX-raydiffractionanalysis,energydispersiveX-rayspectroscopyandtransmissionelectronmicroscopy.Itisfoundthattheconductivityhasbeengreatlyimprovedbytheadditionof30mol%SnandPtnanoparticlesarewelldispersedonTi_(0.7)Sn_(0.3)O_2supportwithanaveragesizeof2.44run.ElectrochemicalstudiesshowthattheTi_(0.7)Sn_(0.3)O_2nanoparticleshaveexcellentelectrochemicalstabilityunderahighpotentialcomparedtoVulcanXC-72.Theas-synthesizedPt/Ti_(0.7)Sn_(0.3)O_2exhibitshighandstableelectrocatalyticactivityfortheoxygenreductionreaction.ThePt/Ti_(0.7)Sn_(0.3)O_2catalystreservesmostofitselectrochemicallyactivesurfacearea(ECA),anditshalfwavepotentialdifferenceis11mV,whichislowerthanthatofPt/XC-72(36mV)under10hpotentialholdat1.4Vvs.NHE.Inaddition,theECAdegradationofPt/Ti_(0.7)Sn_(0.3)O_2is1.9timeslowerthancommercialPt/XC-72under500potentialcyclesbetween0.6Vand1.2Vvs.NHE.Therefore,theassynthesizedPt/Ti_(0.7)Sn_(0.3)O_2canbeconsideredasapromisingalternativecathode,catalystforprotonexchangemembranefuelcells.
简介:MagnesiumalloyEZ10(Mg-RE-Zn)wasdeformedintensionattemperaturesfrom20upto520°C.Arapiddecreaseoftheyieldandtensilestrengthwithtemperaturewasobservedattemperatureshigherthan300°C.Ontheotherhand,ductilityofsamplesrapidlyincreasedinthesametemperaturerange.Lightmicroscopyandscanningelectronmicroscopywasusedtorevealthereasonforthesebehaviours.Intermetallicparticlesingrainboundariesareresponsibleforexcellentmechanicalpropertiesatlowertemperatures.Diffusionalprocessesoccurringattemperatureshigherthan300°Csignificantlyinfluencedthedeformationmechanismaswellasthefracturecharacter.
简介:Zr1-xTixCo(x=0,0.1,0.2,0.3)alloyswerepreparedbyarc-meltingmethodandtheeffectofTisubstitutiononhydrogenstoragepropertieswasstudiedsystematically.Hydrogendesorptionpressure-composition-temperature(PCT)measurementswerecarriedoutusingSievert’stypevolumetricapparatusforZrCo(at473K,573Kand673K)andZr1-xTixCoalloys(at673K),respectively.ProductsafterdehydrogenationwerecharacterizedbyX-raydiffraction(XRD).Inaddition,thekineticsofZr1-xTixCohydridewasinvestigatedat473Kand673K,respectively,underhydrogenpressureof5MPa.ResultsshowedthatTisubstitutionforZrdidnotchangethecrystalstructureofZrCophase.Withtheincreaseoftemperaturefrom473Kto673K,theextentofdisproportionationforZrCoalloyincreased.WithTicontentincreasingat673K,thedesorptionequilibriumpressureofZr1-xTixCo-H2systemselevatedandthedisproportionationreactionofZr1-xTixCoalloyswasinhibitedeffectively.TisubstitutiondecreasedthekineticsrateandtheeffectivehydrogenstoragecapacityofZr1-xTixCoalloysslightly.Generallyspeaking,itwasfoundthatZr0.8Ti0.2Coalloyhadbetteranti-disproportionationpropertywithlessdecreaseofeffectivehydrogenstoragecapacitywhichwasbeneficialtotritiumapplicationintheInternationalThermonuclearExperimentalReactor(ITER).
简介:Inthisstudy,thecharacterizationandmodificationofwastemagnesiumchips(WMCs),whichwereproducedbyplasticmoldinginagoldmanufacturingfactoryandareusedasMg-richintermetalliccompositesinstoringhydrogen,werediscussedindetail.WMCswereanalyzedusingX-raydiffraction(XRD),X-rayfluorescence(XRF)spectroscopy,differentialscanningcalorimetry(DSC),scanningelectronmicroscopy(SEM),andBrunauer-Emmett-Teller(BET)analysistocharacterizethematerials’structuralproperties.Mechanicalmilling,organictreatment,andinorganicsaltadditionwerecarriedouttomodifytheWMCs’surfacetoprepareMg-richintermetalliccompositesforstoringhydrogen.Themodifiedsampleswereanalyzedusinghigh-pressurevolumetricanalysestocalculatetheirhydrogenstoragecapacity.TheauthorsconcludethatmodifiedWMCwaspromisingasanMg-richintermetalliccompositethatwassuitableforuseinhydrogenstoragewitha4.59wt%capacityat320Cunderahydrogenpressureof60bar.
简介:这份报纸的主要目的是在与不同沉浸时间在模仿的身体液体(SBF)沉浸的Mg-Zn-Zr合金的机械行为上调查腐蚀的效果。在SBF的材料的腐蚀行为被沉浸测试决定。侵蚀的合金的表面被SEM检验。渗出的Mg-2Zn-0.8Zr镁合金的张力的样品为0,4,7,10,14,21和28d沉浸于SBF。测试样品的张力的机械行为在一台电子张力的测试机器上被执行。SEM被用来观察破裂形态学。与沉浸时间,最终的张力的力量(UTS),收益力量(YS)和Mg-2Zn-0.8Zr的延伸(EL)的扩展,样品起初很快减少了然后慢慢地减少了,这被发现。与增加的沉浸从可锻的骨折转变到劈开骨折的合金的主要破裂机制预定,它能被归因强调坑腐蚀引起的集中和embrittlement。
简介:Nano-sizedhexagonalmagnesiumhydroxide(Mg(OH)2)withgooddispersibilitywassynthesizedbyadoubleinjection-hydrothermalmethod,utilizingpolyvinylpyrrolidone(PVP)asanadditiveandwithoptimizedprocessingparameters.SEMandBETanalysisshowedthatthemeanparticlesizeandspecificsurfaceareaoftheMg(OH)2particleswere174nmand50.77m2/g,respectively.TheFT-IRspectraandtheXRDpatternsshowedthatPVPwasadsorbedonthesurfaceoftheMg(OH)2crystal,thuseffectivelylimitingparticleagglomerationandhinderingcrystalgrowthalongthe(101)plane.TGAshowedadecreaseinthedecompositiontemperatureandanincreaseintheweightlossoftheMg(OH)2particlesduetoadditionofPVP.
简介:15%Ag-addedcubicperovskitesSr0.9La0.1TiO3andRuddlesden-Popper(RP)phasesSr2.7La0.3Ti2O7werefabricatedviahydrothermalsynthesis,coldpressingandhigh-temperaturesintering.Thestructureandthermoelectricpropertieswerealsoinvestigatedforallsamples.TheresultsindicatedthatAgprecipitatedasasecondphase.AgadditionmadeelectricalconductivityandabsoluteSeebeckcoefficientenhanced,asaresult,theZTvalueswereenhancedbothfortwoseries.Comparedwithcubicperovskite,RPphasewassubjectedtosmallerimpactbyAgaddition.ThereasonsforenhancingZTvalueandthedifferentimpactfortwoseriesbyAgadditionwerealsodiscussed.
简介:Thecorrosionfatiguebehaviorofepoxy-coatedMg–3Al–1Znalloywasinvestigatedinairand3.5wt%NaClsolution.Epoxycoatingasanewmethodwasusedtoimprovethecorrosionfatiguepropertyofthematerial.Resultsshowthatthefatiguelimit(FL)ofthecoatedspecimensishigherthanthatoftheuncoatedspecimensin3.5wt%NaClsolutionbecauseofthestrengtheningandblockingfunctionsoftheepoxycoating.TheFLofthecoatedspecimensin3.5wt%NaClsolutionisashighasthatinair.Itimpliesthatthecoatedspecimensarenotassensitivetotheenvironmentasthemagnesiumalloy.Thelowtensilestrengthandtheshortelongationofthepureepoxycoatingleadtothatthefatiguecrackofthecoatedspecimenisalwaysinitiatedfromtheepoxy-coatingfilmPoresandpinholesacceleratethefatiguecrackinitiationprocess.PinholesarecausedbythecorrosionreactionsbetweentheepoxycoatingandtheNaClsolution.
简介:研究Cu-Mg-Te-Y合金在铸态、热轧态、冷轧态的组织和元素分布;讨论不同退火温度对Cu-Mg-Te-Y合金组织的改变;分析轧制和退火温度对Cu-Mg-Te-Y合金性能的影响。结果表明,不同的轧制工艺获得的合金组织与铸态合金组织相比差别明显,轧制后合金中Mg元素分布比铸态合金的更加均匀,Cu-Mg-Te-Y合金热轧后Cu2Te相被挤碎,尺寸变小,分布更加弥散,继续冷轧后Cu2Te相则被拉长、压扁,呈细条状。冷轧后的Cu-Mg-Te-Y合金在390℃以下退火1h,组织变化不明显,在550℃退火1h后,冷变形产生的纤维状组织发生完全回复再结晶,加工硬化效果消失,抗拉强度大幅度下降,导电率上升。退火温度在360~390℃范围内,Cu-Mg-Te-Y合金可以获得较好的力学性能。
简介:以Ni0.5Co0.2Mn0.3(OH)2和Li2CO3为原料,TiO2和ZnO为掺杂剂,制备出不同含量钛锌离子复合掺杂的锂离子电池正极材料LiNi0.5Co0.2Mn0.3O2。用XRD、SEM、恒电流充放电、交流阻抗法和循环伏安方法分别研究了不同掺杂量对LiNi0.5Co0.2Mn0.3O2的结构、形貌和其电化学性能的影响。结果表明3%(摩尔分数)的Ti、Zn离子复合掺杂能有效提高LiNi0.5Co0.2Mn0.3O2的倍率放电能力和循环性能。在1C和2C的充放电倍率下,首次放电容量分别为170.4mAh/g和164.8mAh/g,经过50次充放电循环后容量保持率分别为96.3%和94.7%,具有优良的电化学性能。
简介:摘要目的了解打叶复烤生企业产生的职业病危害现在,进行分析评价,以确定防治重点和防治措施。方法采用现场职业卫生学调查和检测、职业健康检查、检查表法等方法对生产企业进行评价。结果该新建项目的总体布局、设备布局、职业病防护设施、个人使用的防护用品、职业卫生管理、卫生辅助设施等符合《中华人民共和国职业病防治法》等法律法规规定;该生产企业生产过程中可能会产生粉尘、噪声、高温等职业病危害因素;检测结果梗包装岗位总尘时间加权平均浓度超标,打叶风分机和除尘室噪声强度超标。结论该烟叶复烤生产企业采取的职业病防护设施可行、有效,但部分作业场所仍需采取有效的防护措施。
简介:采用直流电弧等离子体法蒸发Mg+5%TiO2的混合物并将其在空气中钝化,制备粉体Mg-TiO2复合储氢材料。利用电感耦合等离子光谱发生仪(ICP)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)表征粉体复合材料的成分、相组成及形貌。采用压力–成分–温度(PCT)和差示扫描量热仪(DSC)对Mg-TiO2样品的吸放氢性能进行研究。由PCT测量结果可知,Mg-TiO2复合粉体中镁的氢化焓和氢化熵分别为-71.5kJ/mol和-130.1J/(K·mol),而粉体的氢化激活能为77.2kJ/mol。结果表明,采用电弧等离子体法在超细镁颗粒中加入TiO2催化剂可显著增强镁的吸放氢动力学性能。
简介:利用透射电镜(TEM)和高分辨透射电镜(HRTEM)研究高压扭转大塑性变形纳米结构Al-Mg合金的微观结构演变和位错组态。结果表明:对尺寸小于100nm的晶粒,晶内无位错,其晶界清晰平直;而尺寸大于200nm的大晶粒通常由几个亚晶或位错胞结构组成,其局部位错密度高达10^17m^-2。这些位错是1/2〈110〉型60°位错,且往往以位错偶和位错环的形式出现。在高压扭转Al-Mg合金的超细晶晶粒中,用HRTEM同时观察到分别由0°纯螺型位错和60°混合位错分解产生的Shockley部分位错而形成的微孪晶和层错。这些直接证据证实,通常存在于FCC纳米晶中由晶界发射部分位错而产生孪晶和层错的变形机制,同样可以存在于超细晶FCC金属中。基于实验结果,分析了高压扭转Al-Mg合金中的局部高密度位错、位错胞、非平衡晶界、层错和孪晶等对晶粒细化的作用,提出了相应的晶粒细化机制。
简介:目的:探讨比较华蟾素(cinobufagin)协同顺铂(cisplatin)对人骨肉瘤细胞株MG-63的杀伤作用。方法体外培养骨肉瘤细胞株MG-63细胞,取对数生长期细胞进行实验;采用MTT比色法测定MG-63细胞的生长抑制作用并计算细胞抑制率;流式细胞仪检测骨肉瘤细胞的凋亡率和细胞周期,观察细胞凋亡率的变化情况和药物对细胞周期的抑制作用;原位末端标记法(TUNEL)观察骨肉瘤细胞的凋亡情况并检测细胞凋亡率;相差显微镜观察骨肉瘤细胞生长状况及形态学上的改变。结果华蟾素和顺铂均对骨肉瘤细胞有生长抑制作用,华蟾素组、顺铂组及华蟾素+顺铂组在药物浓度不同时对骨肉瘤细胞的生长抑制作用各不相同,在药物浓度低于80μg/ml时,各实验组药物对细胞的生长抑制作用随药物浓度的增加而上升;当药物浓度达到80μg/ml时,华蟾素组和顺铂组药物对骨肉瘤细胞的生长抑制作用不再增加,但华蟾素+顺铂组药物对细胞的生长抑制作用在药物浓度达到160μg/ml时,抑制作用仍强于其浓度为80μg/ml时。各实验组在药物浓度相同时华蟾素+顺铂对骨肉瘤细胞的生长抑制作用明显强于单独应用华蟾素或者顺铂。结论华蟾素+顺铂对骨肉瘤MG-63细胞的联合杀伤作用明显强于单独应用顺铂或者华蟾素;在抑制骨肉瘤MG-63细胞生长方面,华蟾素协同顺铂对细胞的杀伤作用效果显著,并且具有时间和浓度依赖性。