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1.
Michael Wendt 《Mikrochimica acta》2002,139(1-4):195-200
 Elements in the range 39 ≤ Z ≤ 56 were excited by electrons of an energy between 3 and 15 keV. The X-rays were detected by means of an energy dispersive Si(Li) spectrometer with an ultra-thin polymer entrance window. In all cases Mζ = M5N3 was found to be the most intense M line. Thus, the relative intensity of this line is by definition 100%. For the heavier of the investigated elements some other M lines were observed: M5O3, Mγ and M2N4. Mγ was detectable for Z ≥ 47, starting with a relative intensity of about 5%, which increased rapidly with Z to approximately 10%. M5O3 was first observed for 49-In, with a relative intensity of less than 10%, which increased up to approximately 50% for 56-Ba. Also, M2N4 was observed for Z ≥ 49. The relative intensity of that line is approximately one half of that of Mγ.  相似文献   

2.
The L spectra of the elements 14 ≤ Z ≤ 22 were reinvestigated. Because of the limited energy resolution of the multilayer reflectors neither Ll and Lη nor Lα and Lβ1 could be resolved. Nevertheless, the line Lβ3,4 = L1M2,3 was observed for all elements Z ≥ 16, but not for 14Si and 15P. Exceptions to this are 18Ar and 22Ti. For 18Ar no suitable sample is available. In the case of 22Ti the Lβ3,4 line is overlapped by the O Kα line which has its origin in the oxide surface layer of the Ti standard. In all cases the Lβ3,4 line was observed near to the expected position which was determined by means of the known electron binding energies. The L spectrum of 21Sc was studied for various energies of the incident electrons, E0. These measurements show that Lβ3,4 is much more strongly absorbed in Sc than Ll,η and Lα,β1. From these measurements approximate mass absorption coefficients (m.a.c.) were deduced. The relative net peak height I(Lβ3,4)/I(Lα,β1) decreases from 15% at E0 = 4 keV to 4% at E0 = 20 keV, whereas I(Ll,η)/I(Lα,β1) remains nearly constant at 90%. The peak to background ratio of Ll,η is greater than that of Lα,β1.  相似文献   

3.
A reinvestigation was undertaken in order to obtain reliable data of the relative intensities of the L spectra for the elements 24 ≤ Z ≤ 33. A TAP crystal with a periodicity of 25.757 ? was used as the dispersing element. With this crystal one is able to resolve the lines/bands Ll = L3M1, Lη = L2M1, Lα1,2 = L3M4,5, Lβ1 = L2M4, and Lβ3,4 = L1M2,3. Among the investigated elements 33As is the only one for which the energy of the lines Lα1,2 and Lβ1 is below the L3 absorption edge. For all the other elements the lines Ll, Lη, and Lα1,2 are below the L3 edge, whereas Lβ1 and Lβ3,4 are above this edge. This difference leads to effects of differential absorption, where the absorption is stronger for decreasing line energy. For the net peak height ratio β1/α we obtained results which are of the same order of magnitude as those given by White and Johnson (W&J) in their popular tables. But for l/α and β3,41 our results show an atomic number dependence which is completely different from those given by W&J.  相似文献   

4.
土壤中腐殖酸与稀土离子作用的傅里叶变换红外光谱   总被引:8,自引:0,他引:8  
采用NaOH碱提法提取和纯化了黑土中胡敏酸(humic acid,HA)用傅里叶变换红外光谱(FTIR)研究了HA与La^3 、Ce^3 、Cd^3 和Y^3 4种稀土离子作用前后的光谱特征。结果表明,HA与稀土离子作用后的红外光谱中归属于COO^-1600cm^-1、1400cm^-1处的振动吸收峰增强,表明腐殖酸与稀土离子之间发生了配合作用。  相似文献   

5.
共掺杂稀土配合物Tb0.5Eu0.5(asprin)3phen电致发光的研究   总被引:6,自引:4,他引:6  
合成了共掺杂稀土配合物Tb0.5Eu0.5(asprin)3phen,将其掺杂到导电聚合物PVK中,制成结构为ITO/PVK:RE配合物/PBD/Al的电致发光器件,与PVK:Eu(asprin)3phen体系为发光层的相同结构的器件相比,我们发现铽离子的引入能猝灭PVK的发光,增强铕的发光,而Tb3 本身的发光很弱,几乎看不到,说明Pb3 在其中起到能量的中间传递作用,促进了PVK到Eu^3 的能量传递,本文就器件的发光特性及掺杂体系的能量传递进行了初步讨论。  相似文献   

6.
用ICP-AES和重量法测试了中太平洋M海山不同水深范围内(1300~3000 m)25个富钴结壳样品的稀土元素和常量元素。结果显示M海山富钴结壳为水成结壳,稀土元素总量平均为2084.69μg.g-1,LREE/HREE平均为4.84,具有正的Ce异常。ΣREE(不含Ce)随水深增加而增加,而Ce和LREE/HREE比值则以文石溶跃面为界(水深2000 m)呈现不同的变化,稀土元素这些变化除了与海洋背景颗粒的吸附清扫有关外,还与稀土元素在海水中的行为有关。富钴结壳Ce虽随水深变化,但与水深关系不明显,可能反映其通量恒定。富钴结壳中Ce基本全为Ce(Ⅳ),表明氧化富集过程,这一过程受动力学因素控制。  相似文献   

7.
The intensities of the Fe L lines/bands l = L3M1, η = L2M1, α1,2 = L3M4,5, β1 = L2M4, and β3,4 = L1M2,3 were measured for pure Fe and Fe3O4 using a TAP crystal as the dispersing element. The energy of the exciting electrons, E0, was varied in the range 5 ≤ E0 ≤ 25 keV. For pure Fe the following results were obtained. The net peak height ratio Ll/Lα remains relatively constant with varying E0 at approximately 14%. The E0 dependence of Lη is similar to that of Ll, although Lη is less intense than Ll by a factor of 7. Lβ1/Lα decreases from 20% for E0 = 5 keV to about 5% for 25 keV. Lβ3,4 behaves like Lβ1 but is weaker by a factor of 15. For Fe3O4 a much weaker intensity of Lα was observed which can be partially explained by its stronger absorption. Again, the E0 dependence of Ll and Lη is similar with Ll/Lα = 19% and Lη/Lα = 4%. Lβ1 and Lβ3,4 show a comparable E0 dependence. Lβ1/Lα decreases from 50% for E0 = 5 keV to 34% for 25 keV. Lβ3,4 is weaker than Lβ1 by a factor of about 25. The observed E0 dependence of the different lines was used to estimate a set of mass absorption coefficients. Our value for Lα in Fe agrees well with other data which were deduced from variable E0 measurements but differs considerably from data given by Heinrich and Henke.  相似文献   

8.
以元素分析、红外光谱、差热及核磁进行表征了配体及其五种稀土(La^3+,Eu^3+,Tb^3+,Gd^3+,Yb^3+)配合物,确定了其组成,研究了部分配合物的固态荧光.同时以低温磷光光谱确定了配体的三重态能级为22989 cm^-1,研究了配体与稀土离子的能级匹配情况,详细讨论了配合物的发光性能.结果发现,铽配合物能发出很强的特有荧光,而铕配合物所发荧光很弱,说明配体L与Tb^3+ 的^5D4匹配.对于Tb^3+而言,当2000 cm^-1〈ΔE(T-^5D4)〈3000 cm^-1时,稀土铽离子发出强的荧光;对于Eu^3+ 而言,ΔE(T-^5D1)超过3000 cm^-1时,则几乎不发荧光.  相似文献   

9.
辛仁轩  王建晨 《分析化学》2005,33(2):251-253
研究了ICP光源中铝对稀土元素的影响。测定了0-1000mg/L铝(以氯化铝形式)对试液密度、粘度和提升量的影响。研究了铝对等离子体激发温度,Hα线半宽度及对MgⅡ/MgⅠ强度比的影响。结果表明,在所研究的Al浓度范围内,只要正确选择适宜的操作参数,铝的影响并不明显。稀土元素谱线强度的测定显示,在低观测高度处,Al对稀土元素(Eu、La、Nd、Y、Yb)有显著的抑制作用,随着观测高度的增加,Al的抑制效应逐渐消失。由此推断Al对稀土元素的抑制效应为蒸发原子化干扰,这可能是由于ICP光源中稀土元素与氧化铝形成难熔和难挥发的稀土铝酸盐类化合物有关。  相似文献   

10.
贵州沉积型稀土矿主要含有高岭土-锐钛矿石等矿物,存在高含量Si、Al、Fe、Ti、Zr等难溶基体元素,采用高压密闭微波消解法处理难以将其完全溶解,易使测定结果偏低,需再次消解或进一步电热板敞开酸溶处理,方法耗时长,不利于大批量样品检测需求。同时电感耦合等离子体质谱法(ICP-MS)在测定稀土元素时存在基体效应和质谱干扰,影响了检测数据的准确性。本文采用过氧化钠熔融分解样品,熔融物冷却后引入三乙醇胺溶液,在碱性溶液中,大量基体元素与三乙醇胺形成稳定配合物,并与大量溶剂钠盐存于溶液中,稀土元素与Ca、Mg、Sr、Ba等留存于沉淀,经过滤,实现稀土元素与大量基体元素分离,随后沉淀用(1+1)硝酸复溶,并以103Rh和185Re为在线注入内标协同降低基体干扰;启用动能歧视(KED)模式以降低测定过程中潜在的质谱干扰。实验结果表明:高压密闭微波消解法消解液浑浊有残渣,溶矿耗时长,测试结果偏低,碱溶法酸化后溶液清亮透明,稀土元素测定值准确性高;经条件试验,采用10%三乙醇胺溶液提取能较大降低基体干扰;启用KED模式可降低测定过程中的质谱干扰,且准确度优于STD模式;碱溶法方法检出限为0.008μg/g~0.049μg/g,测定下限为0.034μg/g~0.195μg/g,相对标准偏差RSD在0.78%~10.2%之间,相对误差RE在0.0225%~13.5%之间。经实际样品验证,碱熔法较适用于贵州沉积性稀土矿中16种稀土元素的测定。  相似文献   

11.
Polymerization of n‐octylallene was successfully carried out using a conventional binary rare earth catalytic system composed of rare earth tris(2‐ethylhexylphosphonate) (Ln(P204)3) and tri‐isobutyl aluminum (Al(i‐Bu)3) for the first time. The effects of catalyst, solvent, reaction time and temperature on the polymerization of n‐octylallene were studied. The resulting poly(n‐octylallene) has weight‐average molecular weight of 11000, molecular weight distribution of 1.4 and 96% yield under the moderate reaction conditions: [Al]/[Y] =50 (molar ratio), [n‐octylallene]/[Y] =100 (molar ratio), polymerized at 80°C for 20 h in bulk. The poly(n‐octylallene) obtained consisted of 1,2‐ and 2,3‐polymerized units, and was characterized by FT‐IR, 1H NMR and GPC. Further investigation shows that the polymerization of n‐octylallene has some living polymerization characteristics, preparing the polymer with controlled molecular weight and narrower molecular weight distribution.  相似文献   

12.
在回流的正戊醇中,以RE(acac)3·nH2O (acac=乙酰丙酮一价阴离子)为模板,以DBU(1,8-二氮杂双环[5.4.0]十一烯-7)作催化剂,在回流的正戊醇中与4,5-二(4-甲氧苯氧基)邻苯二甲氰反应,我们合成了一系列的15个新型稀土对称二层配合物M[Pc(MeOPhO)8]2[M=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu;H2Pc(MeOPhO)8=2,3,9,10,16,17,23,24-八(4-甲氧苯氧基)酞菁]。整个系列的对称二层配合物主要借助于UV-Vis,IR谱学手段得到充分的表征。所有的研究表明在两个大环之间存在强烈的π-π相互作用,空穴主要位于酞菁大环配体上。  相似文献   

13.
BTMPPA与HPMBP协同萃取稀土元素(Ⅲ)的研究   总被引:2,自引:1,他引:2  
孙静  李德谦 《应用化学》1994,11(3):49-53
研究了二(2,4,4-三甲基戊基)膦酸(BTMPPA,HL)和1-苯基-3-甲基-4-苯甲酰基吡唑酮-5(HPMBP,HA)的苯溶液在不同矿物酸介质中,对稀土元素(Ⅲ)的AA类协同革取。以Nd ̄(3+)、Yb ̄(3+)为例,研究了BTMPPA-HPMBP苯溶液从HNO_3介质中协同萃取稀土元素(Ⅲ)的机理。用斜率法确定了协萃配合物组成为Nd(HL_2)A_2、Yb(HL)2)_2·A·HA,计算了协萃平衡常数。  相似文献   

14.
用对-苯二甲酸铵和邻菲罗啉与氯化铕和氯化镧在乙醇-水溶液中反应,合成了对-苯二甲酸邻菲罗啉铕镧异核稀土配合物,测定了配合物的C,H,N和稀土元素的含量、红外光谱、紫外光谱及荧光光谱,确定了配合物的组成。结果表明,羧基氧和邻菲罗啉氮原子均与稀土离子配位,桥联配体对-苯二甲酸根可有效的传送能量,不发光的镧离子对铕离子的发光有明显的增强作用。  相似文献   

15.
稀土配合物Tb(3-metho)3phen掺杂的有机电致发光   总被引:2,自引:1,他引:2  
合成了一种新型稀土配合物Tb(3-metho)3phen,将其掺杂到导电聚合物PVK中改善了配合物的成膜性和导电性,并对掺杂薄膜进行了荧光,电致发光和形貌的研究,实验表明,存在聚合物到稀土配合物的能量传递,利用能量传递我们得到了窄谱带的绿色有机薄膜电致发光器件。  相似文献   

16.
在乙腈溶液中合成了N,N′-二吡啶基-3-亚甲基-1,2-乙二胺(L)的稀土硝酸盐系列配合物.利用元素分析、 红外光谱和差热-热重分析等手段对所合成的配合物进行了表征,结果表明合成的配合物都符合稀土金属离子与配体为1∶1的化学计量比,其组成可表示为[RE(NO3)3L]·nH2O [RELa(Ⅲ),Nd(Ⅲ),Eu(Ⅲ),Tb(Ⅲ),Er(Ⅲ),n2.5,1.5,1].另外,初步研究了其中Eu(Ⅲ)和Tb(Ⅲ)配合物在室温固体状态下的荧光性质,结果显示这两个配合物表现出相应的Eu(Ⅲ)和Tb(Ⅲ)离子的特征发射.  相似文献   

17.
对未知复杂矿物样品采用扫描电子显微镜-能谱法解析样品,确定基本成分后选择合适的样品前处理方法。实验中采用过氧化钠熔融法熔解样品,用水浸出,硝酸酸化后制备待测样品溶液。以Rh为内标,用八极杆碰撞/反应池(ORS)-电感耦合等离子体质谱(ICP-MS)法测定了复杂样品中的稀土元素。多次测定同一混合标准溶液结果的相对标准偏差(RSD,n=11)小于4%,加标回收率为90%~110%。方法适用于未知复杂矿物中稀土元素的测定。  相似文献   

18.
[{N^N}M(X)(thf)n] alkyl (X=CH(SiMe3)2) and amide (X=N(SiMe3)2) complexes of alkaline earths (M=Ca, Sr, Ba) and divalent rare earths (YbII and EuII) bearing an iminoanilide ligand ({N^N}?) are presented. Remarkably, these complexes proved to be kinetically stable in solution. X‐ray diffraction studies allowed us to establish size–structure trends. Except for one case of oxidation with [{N^N}YbII{N(SiMe3)2}(thf)], all these complexes are stable under the catalytic conditions and constitute effective precatalysts for the cyclohydroamination of terminal aminoalkenes and the intermolecular hydroamination and intermolecular hydrophosphination of activated alkenes. Metals with equal sizes across alkaline earth and rare earth families display almost identical apparent catalytic activity and selectivity. Hydrocarbyl complexes are much better catalyst precursors than their amido analogues. In the case of cyclohydroamination, the apparent activity decreases with metal size: Ca>Sr>Ba, and the kinetic rate law agrees with RCHA=k[precatalyst]1[aminoalkene]1. The intermolecular hydroamination and hydrophosphination of styrene are anti‐Markovnikov regiospecific. In both cases, the apparent activity increases with the ionic radius (Ca<Sr<Ba) but the rate laws are different, and obey RHA=k[styrene]1[amine]1[precatalyst]1 and RHP=k[styrene]1[HPPh2]0[precatalyst]1, respectively. Mechanisms compatible with the rate laws and kinetic isotopic effects are proposed. [{N^N}Ba{N(SiMe3)2}(thf)2] ( 3 ) and [{N^N}Ba{CH(SiMe3)2}(thf)2] ( 10 ) are the first efficient Ba‐based precatalysts for intermolecular hydroamination and hydrophosphination, and display activity values that are above those reported so far. The potential of the precatalysts for C? N and C? P bond formation is detailed and a rare cyclohydroamination–intermolecular hydroamination “domino” sequence is presented.  相似文献   

19.
灼烧时间对稀土氧化物粒度、比表面积和形貌的影响(Ⅲ)   总被引:7,自引:2,他引:7  
将在一定沉淀条件下制备的稀土草酸盐在850℃下灼烧1-24h,得到Nd2O3,Eu2O3和Y2O3样品。利用Coulter地数法,比表面积分析仪和扫描电镜研究了灼烧时间对稀土氧化物的粒度,比表面积和形貌的影响。结果表明,长时间灼烧虽有利于改善颗粒的粒度分布,但会导致颗粒的比表面积急剧减小,且在产品中生成大的团聚体。  相似文献   

20.
钡以及轻稀土元素氧化物对中、重稀土元素的干扰一直是质谱测试中存在的问题。建立了石墨粉垫底碳酸钠-硼酸混合熔剂熔融前处理样品,以103Rh为内标校正,一体化碰撞反应-电感耦合等离子体质谱仪法测定地质样品中稀土元素含量的方法。探讨了碳酸钠-硼酸混合熔剂熔融前处理样品注意事项、碰撞模式下碰撞气流量和离子透镜的参数的优化、干扰校正试验等问题,采用国家标准物质GBW07403、GBW07405、GBW07427、GBW07429验证,实验结果表明,各元素线性关系良好,相关系数均大于0.999,方法检出限在0.01~0.03mg/kg之间,相对误差为0.13%~7.1%,相对标准偏差为0.79%~6.59%,测试结果与标准值相吻合。对实际样品分析,得到平滑的球粒陨石归一化的稀土元素配分曲线,证明测定结果是合理可信的。该方法熔剂用量少,过程空白低,对器皿的侵蚀小,直接加热浸取,简化了操作过程,适用于大批量地质样品中稀土元素的测定。  相似文献   

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