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1.
Thesolidelectrolyteisakeycomponentofsolidoxidefuelcell (SOFC) .Dopedceriaisoneofpromis inghigh conductingsolidelectrolyteinSOFC[1,2 ] .Butitiswell knownthatitisdifficulttosinterdopedceriabysolidstatereactioninair .TheCe0 .9RE0 .1O2 -δelectrolytematerialswerepreparedbythesol gelmethod .Thesinteringtemperatureofthesamplescandecreasetoabout 4 0 0K .Theionicconductivityandlinearthermalexpansionpropertiesofsol gelpreparedCe0 .9RE0 .1O2 -δinawidetemperaturerangewerein vestigated .Thepowder…  相似文献   

2.
RE(NO_3)_3-HNO_3-P507-kerosene extraction system(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y)was studied by the response surface technique.14 models for extracting single rare earth ele-ment in a broad range of acidity and initial rare earth concentration were obtained by using the stepwiseregression method.Three-dimensional display of the response surface of the model of extracting Er~(3 )wasshowed as an example,which reveals clearly the dependence of distribution ratio upon both initial acidity and ini-tial rare earth concentration.  相似文献   

3.
The extraction of RE(Ⅲ) (RE=La, Nd, Sm, Gd) in sulfuric acid medium using the mixture of HDEHP(H2B2) and HEH/EHP(H2L2) was investigated. The synergistic enhancement coefficient(R) was calculated for La (1.96), Nd(3.52), Sm(5.96), and Gd(5.71), respectively, at pH=2.0, and it was seen that the R increased with the increase of aqueous quilibrium pH. The configuration of the extracted complexes was considered to be RE(SOa)xH2x(HB2)3 with HDEHP, RE(SOa)xH2x(HL2)3 with HEH/EHP, and RE(HB2)2(HL2) with their mixture as the extractant with the slope method. The equilibrium constants and stability constants were calculated. A cation exchange mechanism was proposed as well.  相似文献   

4.
Themetalcomplexesofhydrazideshaveattractedconsiderableinterestowingtotheirantifungalandantibacterialactivities[1 ,2 ] .Theycanalsobeusedasanalyticalreagents[3 ]andextractingagentsformetalsalts[4 ] .Manycomplexesofhydrazideshavebeensynthesizedandcharacterized[5]…  相似文献   

5.
BaTiO3 ceramics doped with various quantities of Nd2O3, Sm2O3, Gd2O3, Dy2O3 and Er2O3 were prepared respectively ( the adulterate concentrations were 0. 001,0. 002, 0. 003, 0.005, 0. 007 mol fraction) through a sol-gel method and their electrical properties were researched. It is found that each adulteration of Nd2O3, Sm2O3 Gd2O3,Dy2O3 and Er2O3 all can make the resistivity of BaTiO3 ceramics decline , especially Sm2O3 and Gd2O3. When the addition of Sm2O3 is 0. 001 mol, the resistivity is the smallest, declining from 4.0 × 1012 to 6.5 × 103 Ω different kind of rare earth exhibits different regularity. The grain resistance of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 exhibits a NTC effect, at the same time the grain boundary resistance has a PTC effect, and the grain boundary resistance is much larger than the grain resistance, so the PTC effects of BaTiO3 ceramics doped with Sm2O3 or Gd2O3 originate from the grain boundary. The additions of Nd2O3 , Gd2O3 or Er2O3 make the dielectric constant and the dielectric loss of BaTiO3 ceramics change evidently, especially Nd2O3. The dielectric constant is larger than that of pure BaTiO3 ceramics, on the other hand, the dielectric loss is much lower, which is useful in capacitor fields.  相似文献   

6.
刘睦清  高忆慈 《稀土》2006,27(5):15-19
合成了2,3-二氯异丁酸根和4-甲基吡啶氮氧化物稀土三元配合物(RE=La、Ce、Pr、Nd、Sm、Eu).通过元素分析、红外、紫外、荧光、X射线粉末衍射、XPS、热分析以及摩尔电导等分析手段,确定了配合物的组成为[REL3(4-picNO)H2O](L= CH3C2H2Cl2COO -),并对它们的性质进行了讨论.  相似文献   

7.
RE-NiO(RE=La,Nd,Sm,Gd) catalysts were prepared by a modified sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),BET surface area analysis,H 2 temperature-programmed reduction(H 2-TPR),and O 2 temperature-programmed desorption(O 2-TPD).The oxidative dehydrogenation of ethane(ODHE) to ethylene was applied to evaluate catalytic performance of the samples.The results showed that the doping of RE affected the physicochemical properties of the catalysts.The strong interaction between Gd and NiO played an important role in the lessened reducibility and the distribution of adsorbed oxygen species,consequently influenced the catalytic performance.The best yield to ethylene of 29% was obtained over the Gd-NiO catalyst with an ethane conversion of 56%.  相似文献   

8.
通过感应熔炼制备La0.65RE0.10Mg0.25Ni3.55i0.15(RE =La,Ce,Pr,Nd,Sm)合金.采用X射线衍射方法分析了合金的相结构,研究了其电化学性能,并采用电化学阻抗谱分析了合金电极的放氢动力学特性.研究结果表明,合金是以LaNi5、LaNi3为主相的多相结构,同时合金中少量的Si元素与Mg和Ni元素形成了少量的Mg2 Si相和Ni2Si相.Ce,Pr,Nd,Sm部分替代La以后,合金的放电容量下降,Ce的替代使合金容量大幅度降低.对于本系列合金,La被其他稀土元素部分替代后,合金经过100次循环后的容量保持率略有下降,但除了Pr元素以外,变化值均较小.合金电极的电化学阻抗谱分析表明,中低频区的容抗弧半径依次为Ce >La> Nd >Sm >Pr,这表明采用Nd、Sm、Pr替代La后合金电极在碱液中放电过程电荷传递电阻Rct减小,即合金表面活性增加,但Ce替代却导致Ret急剧增大,这可能与Ce在碱液中易形成氧化物降低了合金的表面活性有关.  相似文献   

9.
金属钕及氧化钕中稀土杂质光谱测定   总被引:2,自引:0,他引:2  
李楠 《稀有金属》1999,23(2):117-120
在色散0.25mm/mm光栅光谱仪上,以控制气氛直流电弧粉末地测定了金属钕及氧化钕中氧化镧、氧化铈、氧化镨、氧化钐、氧化钆、氧化镝和氧化钇。采用正交设计实验,确定了测定条件。测定的下限对氧化铈、氧化镨为0.05%,氧化镧、氧化钐、氧化钆、氧化镝和氧化钇为0.03%,相对标准偏差为6% ̄18%。  相似文献   

10.
Preparation,StructuralCharacterizationandThermalDecompositionMechanismofRareEarthSaltsof3-Nitro-1,2,4-Triazol-5-OneZhangTongl...  相似文献   

11.
Therareearthelements,fromlanthanumtolute tium(atomicnumbers57~71),aremembersof GroupIIIAintheperiodictableandallhavevery similarchemicalandphysicalproperties.Thisuni formityarisesfromthenatureoftheirelectroniccon figurations,leadingtoaparticularlystabl…  相似文献   

12.
Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth (RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave (FP-LAPW) method as implemented in the Wien2k code. In this approach the generalized gradient approximation (GGA) was used for the exchange-correlation (XC) potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied DMSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level (EF). The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough (far configuration) for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.  相似文献   

13.
Rare earth (RE) ternary complexes of Eu0.5Ln0.5(NPPD)3·(DPQ) (HNPPD=1-(naphthalen-2-yl)-3-phenylpropane-1,3-dione; DPQ= dipyridobenzoquinone) and Eu1-xLax(NPPD)3·(DPQ) (Ln3+=La3+, Gd3+, Sm3+, Pr3+; x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9) were synthesized by the reaction of RECl3·6H2O with HNPPD and DPQ in stoichiometry. The complexes were characterized with IR, elemental analysis, TGA-DSC and wide-angle X-ray diffraction. The UV-Vis absorption spectra and fluorescence properties of the complexes were also investigated. The experimental results showed that the luminescence efficiency of Eu3+ complexes was enhanced by doping some other lanthanide ions. Eu0.7La0.3(NPPD)3·(DPQ) showed the highest luminescence efficiency.  相似文献   

14.
Five novel ternary complexes were synthesized by the rare earth with 2,6-pyridine dicarboxylic acid andα-picolinic acid.These complexes were characterized by elemental analysis,molar conductivity,FT-IR,UV-Vis,Raman,TG-DTA and XRD.The general formula of the complexes was[RE(DPA)(L α )(H2O)]·2H2O(RE=Pr 3+ ,Nd 3+ ,Sm 3+ ,Eu,Er 3+ ;DPA=2,6-pyridine dicarboxylic acid;L α =α-picolinic acid). The investigation of fluorescence properties of the Eu-complex showed that the Eu(III)ion could be sensitized efficiently by the ligand to some extent.The antibacterial activity test indicated that all the five complexes exhibited antibacterial ability against Escherichia coli and Staphylococcus aureus with broad antimicrobial spectrums.  相似文献   

15.
Theintermetalliccompoundswithtransitionalbondingfeaturesoftenhaveverycomplexcrystalstructuresanduniquephysicalandchemicalproperties.Owingtotheirpartialdirectionalandpartialsaturationalfeaturesofthebonds,thevalenceruleandtherulesformetalliccompounds…  相似文献   

16.
Snakevenomscontaincomplexproteinswhichpossessvariousbiologicalactivities ,in cludingaclassthataffectscoagulationsystemwithcoagulantoranticoagulantactivities .Ananticoagulantfactor (ACF)waspreviouslyiso latedfromthevenomofAgkistrodonacutusfromsouthernAnhu…  相似文献   

17.
NewVarietiesofNa-Ca-Ba-REFluorocarbonateSeriesMinerals¥YangZhu-Ming;ZhangPei-Shan;TaoKe-Jie(InstituteofGeology,AcademiaSinica...  相似文献   

18.
Perovskite typeoxides (generalformulaABO3 )havebeenattractingmuchattentionformorethantwodecadesduetotheirpotentialcommercialapplicationsascatalystsforvariousreactions :oxidationofCO[1~ 3 ] andlighthy drocarbons[4~ 7] ,combustionofnaturalgasorCH4 [8~ 1 1 ] (tocontrolN…  相似文献   

19.
Solidoxidefuelcells (SOFCs)haveseveraldis tinctadvantages ,e .g .,highenergyconversioneffi ciency ,wideadaptabilitytofuels ,theusageofnon preciousmaterials ,noliquids ,nocorrosions ,modularconstructionandmuchlowerproductionofNOx,SOxandnoise .Therefore ,theyreceiveincreasingatten tion[1,2 ] .AtypicalSOFCwhichutilizesyttria stabi lizedzirconia (YSZ)astheelectrolyterequireshighoperationtemperaturesuchas 10 0 0℃togainhighe noughionicconductivity .Loweringtheoperationtem peratureto 80 0℃wou…  相似文献   

20.
The effects of rare earth(RE)on the structure,acidity,and catalytic performance of HZSM-5 zeolite were investigated.A series of RE/HZSM-5 catalysts,containing 7.54% RE(RE=La,Ce,Pr,Nd,Sm,Eu or Gd),were prepared by the impregnation of the ZSM-5 type zeolites(Si/Al=64:1)with the corresponding RE nitrate aqueous solutions.The catalysts were characterized by means of FT-IR,UV-Vis,NH3-TPD,and IR spectroscopy of adsorbed pyridine.The catalytic performances of the RE/HZSM-5 for the catalytic cracking of mixed butane to light olefins were also measured with a fixed bed microreactor.The results revealed that the addition of light rare earth metal on the HZSM-5 catalyst greatly enhanced the selectivity to olefins,especially to propylene,thus increasing the total yield of olefins in the catalytic cracking of butane.Among the RE-modified HZSM-5 samples,Ce/HZSM-5 gave the highest yield of total olefins,and Nd/HZSM-5 gave the highest yield of propene at a reaction temperature of 600℃.The presence of rare earth metal on the HZSM-5 sample,not only modified the acidic properties of HZSM-5 including the amount of acid sites and acid type,that is,the ratio of L/B(Lewis acid/Brnsted acid),but also altered the basic properties of it,which in turn promoted the catalytic performance of HZSM-5 for the catalytic cracking of butane.  相似文献   

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