简介：Nanosheet(S)andnanoplate(P)γ-Al2O3weresynthesizedbysimplehydrothermalmethodsandemployedassupportsforNicatalystsinCO2methanation.BothofthenanostructuredNi/Al2O3catalystsdisplayedgoodactivity.Incomparison,theNi/Al2O3-ScatalystshowedhigherCO2conversionthantheNi/Al2O3-Pcounterpartatthereactiontemperaturerangingfrom250to400°C.ThephysicalandchemicalpropertiesofthecatalystsweresystematicallycharacterizedbyN2sorption,X-raydiffraction(XRD),highresolution-transmissionelectronmicroscopy(HR-TEM),hydrogentemperature-programmedreduction(H2-TPR)andCO2temperature-programmeddesorption(CO2-TPD)techniques.Higherspecificsurfaceareaandstrongermetal-supportinteractionswereconfirmedontheNi/Al2O3-Scatalyst,whichmayleadtosmallerparticlesizeofNinanoparticles.Moreover,theNi/Al2O3-Scatalystpossessedmoreabundantweakandmediumbasicsites,whichwouldbenefittheactivationofCO2.ThesmallerNisizeandmoresuitablebasicsitesmayrationalizethesuperioractivityoftheNi/Al2O3-Scatalyst.Besides,theNi/Al2O3-Scatalystexhibitedexcellentstabilityat325°Cfor40h.

简介：以硝酸镍为金属离子源、对苯二甲酸为配体，N，N-二甲基甲酰胺为溶剂。采用溶剂热法合成了金属-有机骨架Ni-MOF，采用X射线粉末衍射、N2吸附／脱附、扫描电镜、红外光谱和热重分析等方法对样品进行表征，考察了反应时间对样品结构及吸附性能的影响，测试了样品的c0，的吸附性能。结果表明，150℃反应4h后得到Ni-MOF球形晶体，延长反应时间对Ni-MOF的结构及性能没有明显影响。样品的BET面积为1200～1221m2／g，平均孔径为1．95nm，在常压27℃时，对CO2的吸附量为17．9％，经10次吸附／脱附循环实验后，吸附量稳定在16．5％～17．9％，是一个良好的吸附材料。

简介：NanocrystallineMg2Ni-typealloyswithnominalcompositionsofMg20Ni10–xCux(x=0,1,2,3,4,massfraction,%)weresynthesizedbyrapidquenchingtechnique.Themicrostructuresoftheas-castandquenchedalloyswerecharacterizedbyXRD,SEMandHRTEM.Theelectrochemicalhydrogenstorageperformancesweretestedbyanautomaticgalvanostaticsystem.ThehydridinganddehydridingkineticsofthealloysweremeasuredusinganautomaticallycontrolledSievertsapparatus.Theresultsshowthatalltheas-quenchedalloysholdthetypicalnanocrystallinestructureandtherapidquenchingdoesnotchangethemajorphaseMg2Ni.Therapidquenchingsignificantlyimprovestheelectrochemicalhydrogenstoragecapacityofthealloys,whereasitslightlyimpairsthecyclingstabilityofthealloys.Additionally,thehydrogenabsorptionanddesorptioncapacitiesofthealloyssignificantlyincreasewithrisingquenchingrate.

简介：Thispaperreportsonthelongevityofglycerol-dry(CO2)reformingoverthelanthanum(La)promotedNi/Al2O3catalysts.TheXRDresultsshowedthattheNiparticlewaswell-dispersedinthepresenceofLapromoter.Inaddition,viatheNH3-TPDanalysis,itwasfoundthattheLapromoterhasreducedtheacidityofNicatalystwhichmayhaveexplainedthemitigationofcarbonlaydown.Itwasdeterminedthatthe3.0wt%La-promotedNi/Al2O3catalystpossessedthelargestBETspecificsurfaceareaof97m2g-1.Consequently,ityieldedthebestcatalyticlongevityperformancewithconversionattainedmorethan90%,evenafter72hofreactionduration.Significantly,itcanbeconfirmedthatthepresenceofCO2duringtheglyceroldryreformingwasessentialinreducingcarbondeposition,mostlikelyviagasificationpathway.Thishasensuredastabilityofcatalyticactivityforalongreactionperiod(72h).

简介：ThecorrelationbetweenphasestructuresandsurfaceacidityofAl2O3supportscalcinedatdifferenttemperaturesandthecatalyticperformanceofNi/Al2O3catalystsintheproductionofsyntheticnaturalgas(SNG)viaCOmethanationwassystematicallyinvestigated.Aseriesof10wt%NiO/Al2O3catalystswerepreparedbytheconventionalimpregnationmethod,andthephasestructuresandsurfaceacidityofAl2O3supportswereadjustedbycalciningthecommercialγ-Al2O3atdifferenttemperatures(600–1200C).COmethanationreactionwascarriedoutinthetemperaturerangeof300–600Catdifferentweighthourlyspacevelocities(WHSV=30000and120000mL·g-1h-1)andpressures(0.1and3.0MPa).ItwasfoundthathighcalcinationtemperaturenotonlyledtothegrowthinNiparticlesize,butalsoweakenedtheinteractionbetweenNinanoparticlesandAl2O3supportsduetotherapiddecreaseofthespecificsurfaceareaandacidityofAl2O3supports.Interestingly,NicatalystssupportedonAl2O3calcinedat1200C(Ni/Al2O3-1200)exhibitedthebestcatalyticactivityforCOmethanationunderdifferentreactionconditions.LifetimereactiontestsalsoindicatedthatNi/Al2O3-1200wasthemostactiveandstablecatalystcomparedwiththeotherthreecatalysts,whosesupportswerecalcinedatlowertemperatures(600,800and1000C).ThesefindingswouldthereforebehelpfultodevelopNi/Al2O3methanationcatalystforSNGproduction.

简介：Anewcompoundbasedonpolyoxovanadate[{Ni(en)2}2Sb8V14O42]·5.5H2O(en=ethylenediamine)(1)wassynthesisedhydrothermallyasblackrhombuscrystals.Compound1crystallizedinthemonoclinicsystemwithspacegroupP21/n,Z=4,a=1.46953(9)nm,b=1.28623(8)nm,c=1.76008(11)nm,β=105.7230(10)°.Intheasymmetricunit,cluster{Sb8V14O42}canbeconsideredasanSbderivativeofthe{V18O42}unit.Each{Sb8V14O42}clusterasabuildingblockinterconnectedtofourotherneighboringunitsby{Ni(en)2}bridginggroupswhicharelinkedthroughtheterminaloxygenatomsofthepolyoxoanions,formingatwodimensionalnetwork.

简介：2件1Cr17Ni2钢制氮气气瓶使用前经水检、气检和疲劳等试验后发现气瓶瓶体存在漏点。通过宏微观形貌观察、能谱分析、金相检查和硬度测试等手段,结合气瓶的加工及热处理工艺,确定了气瓶裂纹的性质和原因。结果表明：2个气瓶裂纹的性质均为应力腐蚀开裂,建议调整气瓶焊接后的退火温度,降低其应力腐蚀敏感性,并建议对焊接过程进行全方位控制,防止焊接电极接触瓶体等不规范操作行为。

简介：Theaimofthisresearchistopulseco-depositnano-CeO2particlesintoNi-W-Balloycoatingsinordertoimprovethesurfaceproperties.Theinfluenceofpulsefrequencyanddutycircleondepositionrate,microhardnessandmicrostructures,andtheinfluenceofheattreatmenttemperatureonphasestructures,microhardnessandabrasivityofNi-W-B-CeO2compositecoatingswereinvestigated.Theresultsindicatedthatthepulseco-depositionofnickel,tungsten,boronandnano-CeO2particlefromthebathwhichnano-CeO2particlewassuspendedbyhighspeedmechanicalstirringledtotheNi-W-B-CeO2compositecoatings,possessingbettermicrohardnessandabrasionresistancewhenheat-treatedat400℃for1h.Themicrohardnessas-depositedwith636Hzandthedepositionratewith0.0281mm·h-1wasthehighestatpulsefrequencywith1000Hzandpulsedutycirclewith10%.Microstructuresanalysisdisplaysthatdecreasingpulsedutycycleleadstorefinementingrainstructuresandtheimprovementofmicrostructures.X-raydiffractionshowsthatthecompositecoatingas-depositedwasmainlyintheamorphousstateandpartiallycrystallized,butwhenheattreatedat400℃,thecrystallizationtrendwasstrengthenedfurther.

简介：分析了缓冲溶液中不同ｐＨ条件下所合成Ｎｉ（ＯＨ）２的平均晶粒度，并运用循环伏安法快速检测了其电化学性能。结果表明合成的ｐＨ值越大，所得Ｎｉ（ＯＨ）２的平均晶粒度越大，由其制备的电极活性越低，但其循环寿命增加。

简介：在H2,H2+N2及真空气氛下对Fe/2Ni合金进行了烧结,讨论了烧结气氛对合金碳含量以及合金力学性能的影响;指出烧结气氛是通过H2+N2混合气氛中H2脱出合金中的碳,从而影响合金的最终组织来影响合金力学性能的,因此可以通过控制烧结气氛的H2与N2体积比来控制合金中的碳含量,以得到所需的力学性能;并对合金脱碳机理作了初步探讨。

简介：利用恒电流充放电、循环伏安法研究了过量镍粉对Ni（OH）2电极电化学行为的影响，并用X射线衍射分析了放电后镍粉结构的变化。结果表明：电极中的镍粉在碱性电解液中会氧化成活性物质β—Ni（OH）2，从而对放电容量作出贡献，同时因氧化使导电性降低而影响Ni（OH）2的放电效率。利用镍粉作空白试验对照，将电极在第4～6周期的放电容量扣除镍粉的贡献可尽量准确地测定Ni（OH）2的放电容量。

简介：摘要：本文采用可控气氛进行18Cr2Ni4WA材料渗碳处理开展了工艺试验，确定了最佳工艺参数，通过试验可以保证显微组织、碳化物、残余奥氏体符合HB5492的要求，实现了热处理后硬度达到HRC≥62，符合使用要求。

简介：Basedonclustervariationmethod(CVM)andnaturaliterationmethod(NIM),order-disorderphasetransitionintheintercalationcompoundsM1/2TiS2issimulatedbycomputer.Thefavorableconditions,underwhich3a0×a0superstructureisformed,aregiven,andtheresultsareingoodagreementwiththeexperimentsandtheoreticalcalculations.TherelationshipbetweencriticaltemperatureandM-ion-vacancyinteractionparameterislinear.

简介：激光冲击强化是一种新型表面处理技术,利用高功率激光束冲击金属零件表面,在零件表面形成较大的残余压应力,可有效改善零件的疲劳性能。以发动机1Cr11Ni2W2MoV叶片为研究对象,对其进行了激光冲击强化处理,研究强化处理对材料的微观组织和疲劳性能的影响。研究结果表明：相比未处理试样,激光冲击强化在1Cr11Ni2W2MoV叶片材料表层形成较大的残余压应力,表层晶粒更为细化,叶片的疲劳寿命提高1.7倍。

简介：采用电场、磁场、应力场和温度场多场耦合成形与烧结一体化技术制备高致密Fe-2Cu-2Ni-1Mo-0.8C合金,利用光学显微镜和扫描电镜对该合金的显微组织以及磨损表面进行观察和分析,重点研究耦合外加脉冲磁场对合金耐磨性能的影响。结果表明,在电场、应力场和温度场三场耦合放电等离子烧结技术的基础上进一步耦合适合的脉冲磁场,可明显改善烧结合金微观组织和合金元素分布的均匀性,不仅提高合金的耐磨性,同时还可显著提高合金的耐磨性能均匀性。在峰值电流、基值电流、频率、占空比分别为2700A、360A、50Hz和50%的脉冲电流以及烧结压力为30MPa的条件下烧结铁基合金粉末3min,耦合外加脉冲磁场强度为2.36×106A/m时,烧结材料的耐磨性能最佳,合金的磨损机制主要为粘着磨损。

简介：合成了一维绳梯链状双金属化合物[Ni(en)2]3[Fe(CN)6]2·2H2O,并对其变温穆斯堡尔谱进行了研究,结果表明该分子磁体中铁的电子态为低自旋Fe3+,而大的四极分裂值(QS)表明此化合物的[Fe(CN)6]3-单元对称结构发生了形变,低温时出现的磁弛豫谱,给出了在该温度点附近出现铁磁耦合相互作用的信息。

简介：

简介：ThemorphologyandcorrosionbehaviorofNi/Al2O3compositecoatingspreparedusingdouble-pulsedelectrodepositingtechniqueafteroxidizedunder800℃NaCldepositinairenvironmentwereanalyzedbyscanningelectricalmicroscope(SEM),X-raydiffraction(XRD)andenergydispersivespectrum(EDS).TheresultsshowedthatthecorrosionofallcompositecoatingswasacceleratedunderNaCldeposits,andthecorrosionproductswereratherporouswithpooradherencetothematrix.Al2O3particlesinthecoatingscanrefinethegrainsizeandimprovethehightemperaturecorrosionresistanceofthecoatings.Withinthetestscope,themoreAl2O3particlesinthecoatings,thelowercorrosionratescouldbeobtained,andthecorrosionmechanismwasalsodiscussed.

简介：Ca_3Co_2O_6，Na和Ni的电子结构做了模型被被基于的Camhride连续全部的精力包裹(CASTEP)的量化学药品软件学习，在密度函数理论(DFT)和伪潜力上。优点(Z)的电子传导性，seebeckcoefficient，热传导性和图被计算。精力乐队结构在做semiconductors.Na的模型shoivs由于代理杂质揭示杂质层次的形式p类型半导体的特性，而是做Ni的模型是n-typesemiconductor。计算结果证明做的模型的电的传导性比的高非--做的模型，当Seebeck系数和做的模型的热电导率是比非做的那些低的时。因为大增加，电的电导率，做Na的模型的Z被提高，热电的性质被改进。作为Seebeck系数的大衰落，在另一方面，Ni-的Z做了模型不到的非--做的模型。

简介：齿轮组件经500h工作后,有1个齿发生了断裂。通过断口宏微观检查、能谱分析,对断裂齿轮的金相组织、化学成分、硬度、表面粗糙度和烧伤情况进行分析,结合对加工方式跟踪,分析结果表明：该齿断裂性质为疲劳断裂,主要与砂轮磨削加工中产生的镶嵌物有关,结合加工生产实际,建议减少磨削进给量,使用合适的冷却液,必要时加以放大镜以及体视显微镜进行检查,尽量避免或减少镶嵌物的产生。