学科分类
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112 个结果
  • 简介:用EXAFS方法研究了重金属Zn(Ⅱ)在δ-MnO2上吸附的微观结构及吸附机制。在pH5.50,0.1M硝酸钠介质中,吸附-解吸实验表明Zn(Ⅱ)在δ-MnO2上的吸附可逆性很高.EXAFS结果表明,δ-MnO2表面上吸附态Zn2+以六配位的水合离子八面体形式存在。八面体的水合Zn^2+离子与δ-MnO2的结构单元MnO6八面体通过共用O原子结合,形成角-角结合的弱吸附.Zn-O平均原子间距为2.071A,Zn-Mn平均原子间距为3.528A。同一条等温线上随着吸附量增加,角-角结合的弱吸附形式基本上没有变化。Zn(Ⅱ)在δ-MnO2上较高的吸附可逆性是由于吸附态Zn(Ⅱ)与δ-MnO2以弱吸附的角-角形式结合所导致的。

  • 标签: Zn/δ-MnO2吸附结构 EXAFS 重金属污染 硝酸钠 可逆性 解吸
  • 简介:本文观察到BaF2:Gd,Eu通过下转换过程实现可见光发射的量子剪裁过程。Gd3+吸收一个VUV光子,通过交叉弛豫过程把能量传递给两个Eu3+,从而发射出两个可见光光子,实现量子剪裁过程。通过光谱结果的计算,其量子剪裁效率可达194%。

  • 标签: BaF2:Gd Eu 真空紫外量子剪裁 VUV光子 交叉弛豫 可见光光子 光谱
  • 简介:Anew140GHz/2MW/3selectroncyclotronresonanceheating(ECRH)systemcomposedoftwounitsisnowbeingconstructedonHL-2A.Asapartofthesystem,twotransmissionlinesmarkedNo.7&8playtheroleofcarryingmicrowavepowerfromtwogyrotronstothetokamakport.Basedontheoversizedcircularcorrugatedwaveguidetechnology,anevacuatedtransmissionsystemwithhighpowercapabilityandhightransmissionefficiencyisdesigned.Detailsarepresentedforthedesignofthecorrugatedwaveguide,thelayoutoftheproposedlinesandthevacuumpumpingsystem.Thenmodeconversionlossesduetocoupling,misalignment,bendsandgapsarediscussedtoserveasareferenceforanalyzingthetransmissionefficiencyandalignment.Finally,adual-modespropagationcaseconsistingoftheHEnandLPnevenmodesisdiscussed

  • 标签: 电子回旋共振加热系统 HL-2A 输电线路 设计 GHZ 波导技术
  • 简介:StableoperatingregionintheHL-1Mtokamakhasbeenextendedbymeansofwallconditioning,corefuellingandcurrentcontroltechniques.Themechanismsoftheextensionareanalyzedinthispaper.Lithiumizationdiminishestheimpuritiesandhydrogenrecyclingtothelowestlevel.Afterlithiumizationahighdensityupto7×1019m-3wasobtainedeasilybystronggaspuffingwithordinaryohmicdischargealone.MoreattractivelywefoundthatmetalLi-coatingexhibitedtheeffectsofwallstabilization.Thelowqalimitwithhigherdensitywasextendedbyafactorof1.5~2incomparisonwiththatforboronization,and1.2forsiliconization.Siliconizationnotonlyextendedstableoperatingregionsignificantlybyitself,butalsoprovidedagoodtargetplasmaforotherexperimentsofraisingdensitylimit.Corefuellingschemesarefavourableespeciallyforsiliconizedwallwithahigherlevelofmedium-Zimpurity(Z=14).Aftersiliconizationthemaximumdensitynearto1020m-3wasachievedbyacombinationofsupersonicmoleculebeaminjectionandmultipelletinjection.ThenewdefinedslopeofHugilllimitillustratingmoreclearlythesituationunderlowqaandhighnedischargeswascreatedtoindicatethenewregionextendedbycombiningIpramp-upwithcorefuelling.TheslopewithalargeMurakamicoefficientincreasedbyafactorof50~60%.

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  • 简介:LiGaO2与GaN的晶格失配率只有0.2%,是一很有潜力的蓝光衬底材料。本文利用化学侵蚀、光学显微镜、透射电子显微镜对晶体中的缺陷进行了分析,研究了生长参数、原料化学配比对晶体质量的影响及其和晶体中缺陷形成的关系。TEM分析表明,由于原料近非化学计量比挥发致使组份偏离,容易产生γ-Ga2O3包裹物。包裹物和位错形成具有一定的相互促进作用。X射线貌相分析发现提拉法生长LiGaO2晶体中易于形成平行于(001)面的亚晶界,这可能和其沿[001]方向的极性有关。

  • 标签: GAN 外延衬底材料 LiGaO2晶体 X射线貌相术 氮化镓 TEM
  • 简介:ThispaperpresentsabriefoverviewofCO2reformingofCH4(CRM)byvariousformsof'arc'plasma,whichismoresuitabletoCRM,andtheenergyefficiencyisusedtoevaluatedifferentplasmaprocessesspecifically.Accordingtothereportedresults,thearcthermalplasmawithbinodeexhibitedbetterperformance.Moreover,theplasmaCRMprocesswascomparedwiththereportedplasmasteamreformingofCH4(SRM)process,andtheresultsshowedthattheformerprocesshasadvantagesonenergyefficiencyandCH4consumption.Additionally,itisbelievedthattheplasmaCRMprocesswouldbecompetitivewiththeconventionalSRMprocessinbothenergyefficiencyandCO2emissiononcetheheatmanagementisemphasizedandtherenewablepowerisused.Finally,aconceptofplasmareactorforindustrialapplicationisproposed.

  • 标签: 等离子体过程 CO2排放 蒸汽重整 CH4 可再生能源发电 等离子体反应器
  • 简介:PhotocatalystwaspreparedbyimmobilizingTiO_2onglassbeadsusingthetradi-tionalsol-gelmethod.Ultravioletlight(UV)producedbypulsedstreamerdischargewasthenusedtoinducephotocatalyticactivityofTiO_2photocatalyst.Decolourationefficiencyoftherep-resentativeazodye(acidorange7,AO7)wasinvestigatedusingthesynergisticsystemofpulsedstreamerdischargeplasmaandTiO_2photocatalysis.Theobtainedresultsshowedthatthede-colourationrateofAO7couldbeincreasedby16.7%undertheconditionofaddingsupportedTiO_2inthepulsedstreamerdischargesystem,comparedtothatinthesolepulsedstreamerdischargeplasmasystem,duetothesynergisticeffectofpulsedstreamerdischargeandTiO_2photocatalysisinducedbypulsedstreamerdischarge.ThesynergisticsystemofpulsedstreamerdischargeandTiO~photocatalystwasfoundtohavemorereactiveradicalsfordegradationoforganiccompoundsinwater.

  • 标签: 脉冲海洋地震拖缆放电 固体二氧化钛 光催化作用 增效系统
  • 简介:Theoreticalcalculationandexperimentalresultsforapolarizerwithsinusoidalgroovesusedintheelectroncyclotronresonanceheating(ECRH)systemoftheHL-2Atokamakarepresented.Thecalculationisbasedonanintegralmethoddevelopedinthevectortheoryofdiffractiongratings,andthepolarizationcharacteristicsobtainedwithalow-powertestareingoodagreementwiththenumericalcalculatedresults.WiththepolarizerassembledinamiterbendintheECRHtransmissionline,pureordinarymode(O-mode)andextraordinarymode(X-mode)polarizedwavesarealsoexpectedinthehigh-powerexperiment,dependingonthepolarizerrotationangleandthetoroidalinjectionangleoftheelectroncyclotron(EC)wavebeam.Second-harmonicX-modeexperimentsweresuccessfullyexploredinHL-2A.Experimentalresultrevealedthattheelectrontemperatureincreasedfrom0.8keV(Ohmicheatingphase)to1.5keV(secondX-modeheatingphase).

  • 标签: 电子回旋共振加热 偏光镜 采暖系统 正弦 HL 装置
  • 简介:Thepreliminarydesignofamulti-barrelspelletinjectorwithcyclerefrigeratorasanadvancedplasma-fuellingtoolforHL-2Atokamakhasbeenproposed.Thedesignaimsatprecisetemperaturecontrol,easyoperation.withhighreliabilityandhighflexibility.GM-cyclerefrigeratorandpipe-gunStructurehavebeenemployedtoproduce25pelletsin25gunbarrelssimultaneouslyandthedesignaims.havebeenaccomplished.Primedesignprinciple,engineeringparameters,structureandlayoutofthecryostatcomponentsaswellascalculationofheatloadforthecryostatarepresented.

  • 标签: 托卡马克装置 球形注射器 循环制冷 热量损失 散热片