990 resultados para CE-BEM
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用溶胶凝胶法制备了CeO2纳米粒子,XRD分析表明,所合成的CeO2纳米粒子均为立方晶系,空间群为O5hFm3m。TEM分析表明,CeO2粒子为球形。研究了CeO2纳米粒子形成过程中Ce价态的变化与性质,发现干凝胶中Ce3+和Ce4+共存;当焙烧温度低于230℃时,随焙烧温度的升高,Ce3+含量逐渐降低,Ce4+含量逐渐增高,即Ce3+缓慢地氧化成Ce4+;当焙烧温度高于230℃时,Ce3+快速氧化成Ce4+,至250℃时Ce3+完全氧化成Ce4+。焙烧温度低于250℃处理的样品中O1s的光电子能谱明显不同,反映出样品晶格结构的变化。
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Ce∶SrAlF5晶体生长及其光谱特性张吉林(辽阳石油化工专科学校,辽阳111003)洪广言(中国科学院长春应用化学研究所,长春130022)CrystalGrowthandSpectroscopicCharacteristicsofCe:SrAlF...
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非线性光学新材料K2Ln(NO3)5·2H2O(Ln=La,Ce,Pr,Nd,Sm)的晶体生长、结构和表征董文庭张洪杰苏锵(中国科学院长春应用化学研究所稀土化学与物理开放实验室,长春130022)Growth,StructureandCharact...
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The dissolution behaviours of La and Nd in their chloride molten salts were studied by means of the see-through cell, electrochemical weak polarization and quantum chemistry (extended Huckel molecular orbital). The reasons for the low current efficiencies of rare earth metals and the difference between La and Nd in their own chloride electrolytes on the basis of the solubility, rate of dissolution, and existing state of the metals dissolved as well as the structure of the melts, are discussed.
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采用固相反应法在Al2O3-B2O3体系中合成了Al4B2O9和Al18B4O33两个相关化合物,测定了在两种基质中Ce3+,Tb3+和Ce3+-Tb3+的光谱,观察到在两种基质中Ce3+的光谱相似,Ce3+的发射峰位置在Al18B4O33中比Al4B2O9稍有红移。实验表明,Al18B4O33将是一种好的发光基质
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Ce:Nd:LiNbO3晶体具有优良的光折变性能,它作为全息记录介质,用于实现了光学图象微分和全息关联存储。
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采用高温固相反应法,在Ar气氛中合成了KMF3(M=Mg、Ca、Sr、Ba)基质化合物和掺杂Ce3+的磷光体。经X射线衍射分析确定,KMgF3和KCaF3属于立方晶系、钙钛矿型结构,KSrF3和KBaF3具有类似的结构。测定了KMF3∶Ce3+的发光光谱,观察到与其结构对应的分为二种不同的光谱结构,讨论了Ce3+的取代格位
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The larger chemical shift of cerium compounds was discoveried. The chemical states of the cerium compounds were identified by the chemical shifts of Auger energy. The changes in Anger energy and parameters are principally due to the changes in extra-atomic relaxation or polarization energy. The increase of the polarizable properties in anions of cerium compounds corresponds to the increase of Auger energy and parameter. The Auger parameter can be measured more accurately. Ce(CF3COO)(x)Cl-3-x was also studied by ESCA. It is shown that the electron density at cerium atom increases with the increase of x, while the electron density at oxygen atom decreases.
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采用固相反应法合成了接Ce3+、Gd3+、Tb3+的CaLaB7O13,并测定了它们的光谱.在Ce3+的光谱中发现文献中尚未报导的317nm激发峰和293nm发射峰.293发射属于不常见的5d能带中次最低能级向基态的跃迁,并随着Ce3+离子浓度增加而变弱,当掺杂浓度大于0.1mol时,293nm发射峰消失.
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研究了XPS诱导的CeM5N45N45俄歇峰,由于其终态空穴处于芯能级,故俄歇峰有较好的分辨率。从CeM5N45N45的俄歇峰可获得中心离子Ce的电子云密度等信息,发现其俄歇参数与配位体的极化变形程度有关,从而解释了双烯烃定向聚合必须有稀土卤氧键存在的原因。
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我们已经实验证明并报道了Eu-Tb之间、Ce-Yb之间的电荷转移.本文首次实验证实了Ce~(3+)离子和Eu~(3+)离子之间电荷转移现象的存在,进一步阐述了稀土价态与其电子组态共轭特征的相关性.1 实验部分1.1 试剂CaF_2,SrF_2,BaF_2,NH_4HF_2、氢氟酸、盐酸均为分析纯,EuF_3和CeF_3分别由高纯Eu_2O_3(99.95%)及CeO_2(99.99%)自制.1.2 MF_2:Eu,Ce体系的合成按化学计量比(MF_2:X%CeF_2,y%EuF_3;X=1,y=0,0.1,0.3,0.5,1;X=0,0.05,0.1,0.3,0.5,y=1)准确称取原料,放人玛瑙研钵中充分研混后装入刚玉柑涡中,置于管状炉内(用氢气
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Tricyclopentadienyl cerium tetrahydrofuranate (THF) was prepared by the reaction of (NH4)2Ce(NO3)6 with sodium cyclopentadienide(C5H5Na) in THF at molar ratio of 1:6 to give a brown crystal of (eta5-C5H5)3Ce.OC4H8; tricyclopentadienyl erbium tetrahydrofur
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Brown crystalline tricyclopentadienyl cerium tetrahydrofuranate (THF) complex (eta5-C5H5)3Ce(THF) was prepared by the reaction of (NH4)2Ce(NO3)6 with sodium cyclopentadienide (C5H5Na) in THF at molar ratio of 1:6. ErCl3.4THF reacts with potassium cyclooct
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采用固相反应的方法;经二次灼烧合成了掺Ce(3+)、Tb(3+)的Ca3Y2(BO3)4和Sr3Y2(BO3)4磷光体;分析了合成过程中铈的还原情况.用X-射线衍射分析确定了它们的结构均为正交晶系,空间群P21cn测定了Ce(3+)和Tb(3+)在两种基质中的光谱,得到Ce(3+)波长位移的某些规律,观察到Ce(3+)对Tb(3+)的敏化作用.