简介:Agriculturalapplicationofrareearth(RE)hasbeengeneralizedforseveraldecades,anditisinvolvedincrops,vegetablesandstockraisinginChina.However,alltheresearchesonREmainlyfocusonthefieldssuchasplantphysiologicalactivity,physiologicalandbiochemicalmechanism,sanitationtoxicologyandenvironmentalsecurity.PlantprotectionbyusingREandtheinducedresistanceofplantagainstdiseasesweresummarized.Themechanismofrareearthagainstplantdiseaseishighlighted,whichincludesfollowingtwoaspects.First,REelementscancontrolsomephytopathogendirectlyandreduceitsvirulencetohostplant.AnotherpossibilityisthatREelementscanaffecthostplantandinducetheplanttoproducesomeresistancetodisease.
简介:Theneedformoreactiveandhydrothermallystablefluidcatalyticcracking(FCC)catalyststocombattheeffectofmetalcontaminantshasledtoanincreaseindemandforrareearthoxides.RareearthoxidesenhancecatalystactivityandpreventthelossofacidsitesduringtheFCCunitoperation,especiallywhenheavyresiduewithhighmetalcontentisusedasfeed.Inthispaper,areviewwascarriedouttoshowtheeffectsofrareearthelementsonthestructure,activity,andstabilityofFCCcatalysts.Also,theuseofrareearthelementsasvanadiumtrapswasanalyzedinconjunctionwiththemechanismofcatalystdeactivationbyvanadium.TheobjectivewastoelucidatetheinteractionofvanadiumspecieswiththezeolitecomponentoftheFCCcatalystsandtheroleofrareearthelementsincounteringthedeleteriouseffectsofvanadiumontheFCCcatalysts.
简介:Thehistoryofthedevelopmentofthetube&pipedivisionofBaosteelwasreviewedinthearticle,focusingontheprocessoftechnicalinnovationandtheproductcategoryenrichment.Thankstothetechnicalinnovation,theφ140productlinehasbecomethemostefficientoneintheworld.Withtheadvanceofconglomeracyandtheconstructionofthemostadvancedweldpipelineandtheφ460premiumqualityfinishing(PQF)line,thecatalogueofBaosteeltube&pipeproductshascoveredtheextensiverangefromthehotrolltocoldroll,theseamlesstothewelded,andalloftheproductdimensionscopefrom25.4mmto610mm.Tomeettherequirementsofrelevantindustriessuchasenergy,transportation,machinery,ammunitionandotherrelevantindustries,theproductvarietyisdivertingfromcarbonsteeltoalloysteel,stainlesssteelandspecialalloys.AstheBaosteelSteelTubingPlantincreaseditsnumberofproductionunits,expandeditsproductioncapacityanddevelopednewproducts,ithasgrownintoapipeandtubesupplierwithglobalcompetitiveness.
简介:Thereisanincreasingtrendforproducingcopper-containingsteels,withcopperbeingeitheraresidualelementfromscrapsoranintentionaladdition,i.e.,inweatheringsteel.Theissueofsurfacehotshortnessoccursduringthehotworkingofsteelscontainingcopper,andasignificantamountofworkhasbeenperformedonthistopic.Thispaperprovidesareviewofrelatedstudiesonthisphenomenon.Theformationmechanism,asanalyzed,istheliquidmetalembrittlementcausedbytheliquidcopperpenetrationintoaustenitegrainboundariesatthemetalsurface,wherethecopperoriginatesfromtheselectiveoxidationofthesteelathightemperature.Onthebasisofthemechanism,moreimportanceisplacedonanalyzingtheeffectonthephenomenonbyvaryingthecontrollingfactors,includingtheheatingprocess,alloyingadditions,anddeformationconditions.Possiblesolutionstotheproblemarefinalized,andsomefurtherworkmustbeperformedinthefuture.
简介:有色金属的分类很多,大约有80多种,大致按其比重、价格、在地壳中的储量及分布情况和被人们发现与使用情况的早晚等分为五大类。(1)重有色金属;指比重大于4.5的有色金属。包括铜,镍,锢,铅,锌,锑,汞,镉和铋。(2)轻有色金属;指比重小于4.5的有色金属。包括铝,镁,钙、钾、锶和钡。(3)贵金属;指在地壳中含量少,开采和提取都比较困难,对氧和其它试剂稳定,价格比一般金属贵的有色金属。包括金、银。和铂族元素。一般比重都较大,熔点较高在916—3000度,有很好的化学稳定性、优良的抗氧化性及耐腐蚀性。(4)半金属;一般指硅、硒、碲、砷和硼五种元素。其物理化学性质介于金属和非金属之间。如砷是非金属,但它能传热和导电。