ICP－AES法同时测定聚酯切片中的钛和铁

本文介绍ＩＣＰ－ＡＥＳ法同时测定聚酯切片中钛和铁的方法。试样以干法分解，以硫酸，硫酸铵溶解残渣后进行测试。回收率为９３．５％－１００．６％，ＲＳＤ＜３．８３％     

ICP－AES法同时测定柠檬酸中铁、铜、钙、铅

本文介绍了ＩＣＰ－ＡＥＳ法同时测定柠檬酸中铁、铜、钙、铅的方法。试样以干法分解，盐酸溶解残渣后进行测定。回收率为９０．２％－１０５．８％，ＲＳＤ＜２．６６％。     

原子吸收和电感耦合等离子体发射光谱法测定某些重要的埃及植物

本文讨论了用原子吸收和电感耦合等离子体发射光谱法（ＩＣＰ－ＡＥＳ）测定经高压釜溶解的营养性埃及植物，如胡芦巴、甘草和莲座丛，并讨论了该法用于被消解植物样品中多元素日常分析的优点。这些样品具有较宽的元素含量范围，准确地测定这些营养性样品的主量和微量元素特别是有毒元素，对埃及人民的健康非常重要。ＩＣＰ－ＡＥＳ法同时也用于被视为尼罗河净化剂的水生风信子的分析。分析结果表明，该植物能够有效地吸收有毒元素。被研究的植物经高压釜溶解，其溶液经原子吸收和ＩＣＰ－ＡＥＳ法测定。作者对分析结果进行了对比，并阐明了二者之间的关系。     

动物脑组织中微量钙的ICP—AES法测定

本文利用ＩＣＰ－ＡＥＳ法测定了大白鼠脑组织中的微量钙，并对经典的Ｃａ－ＰＯ４干扰体系在ＩＣＰ－ＡＥＳ中的影响进行了实验，结果表明，样品消解后可直接进样，磷不影响钙的测定，方法的ＲＳＤ为１．１６％，样品加标回收率为９７％，优化实验条件下，对降低干扰，提高分析结果的准确度是至关重要的。     

ICP-AES法同时测定螺旋藻中Ca、Mg、P、Fe、Cu、Mn、Zn

本文研究了干法灰化,盐酸溶解盐类,ＩＣＰ－ＡＥＳ技术同时测定螺旋藻中Ｃａ、ｍｇ、Ｐ、Ｆｅ、Ｃｕ、Ｍｎ、Ｚｎ的方法,进行了共存离子干扰和谱线干扰试验,对Ｃｕ、Ｍｎ、Ｚｎ进行了ＡＡＳ法测定对比。方法的相对标准偏差为１．３９％－５．０２％,标准回收率为９５．６％－１０４．８％。方法快速、准确、可靠。     

ICP－AES法同时测定磷铁中的主含量元素和杂质

本文研究用ＩＣＰ－ＡＥＳ法同时测定磷铁的主含量元素Ｐ和杂质元素Ｓｉ、Ｍｎ、Ｔｉ、Ｖ、Ｃｒ的方法。采用碱熔酸化分解试样，选Ｂ为测Ｐ的内标元素，回收率为９６％－１０２％，最大相对标准偏差为８．６０％，大多数结果的相对标准偏差小于５％。     

连续氢化法电感耦合等离子体发射光谱同时测定生物样品…

本文叙述用氢化法电感耦合等离子体发射光谱同时测定生物样品中痕量硒，砷，锡，锑的方法。比较了浓度为２．８８ｍｏｌ／Ｌ，４．８ｍｏｌ／Ｌ和６．０ｍｏｌ／Ｌ的ＨＣｌ对Ｓｅ，Ａｓ，Ｓｎ，Ｓｂ，Ｈｇ和Ｇｅ谱线强度的影响，也比较了ＮａＢＨ４溶液中ＶＣ对测定Ｓｅ，Ａｓ，Ｓｂ，Ｓｎ，Ｈｇ和Ｇｅ的影响。在４．８ｍｏｌ／Ｌ ＨＣｌ浓度下，在１％ＮａＢＨ４溶液中加０．５％ＶＣ，ＨＹ－ＩＣＰ－ＡＥＳ的检出限是：Ｓｅ ０．     

ICP—AES分析中干扰及其校正方法的进展（Ⅱ）

本文对ＩＣＰ－ＡＥＳ分析中的光谱干扰继续进行综述，本文继（１）而继续对ＩＣＰ－ＡＥＳ分析中的光谱干扰进行综述。     

绝对量内标控制ICP－AES法同时测定合金中的多元组分

本文采取在标样和试样中加入绝对量一致的内标元素控制的ＩＣＰ－ＡＥＳ法，对合金中的多元组分进行同时测定。通过对Ａｇ－Ｍｇ－Ｎｉ合金中Ｍｇ、Ｎｉ的分析研究和试样测定，获得较好的准确度、精密度，相对误差Ｍｇ＜±０．５％，Ｎｉ＜±３．０％，相对标准偏差均小于０．５％，能满足对合金分析的要求。适当调整称样量及待测溶液定容体积，可扩大测定范围。采用绝对量内标控制，大大减小了由称量和稀释溶液体积带入的误差，从而提高了分析的准确度和精密度     

ICP—AES法同时测定硼铁中的主要成分及杂质

本文研究了用ＩＣＰ－ＡＥＳ法同时测定硼铁中的主要成分Ｂ、Ｆｅ及杂质元素、Ａｌ、Ｍｎ，Ｓｉ的方法。采用碱熔融法分解样品，选Ｃｄ作为内标元素。     

ICP-AES测定高浓度基体下杂质元素的偏最小二乘法研究

建立了ICP-AES测定高浓度基体中微量杂质元素的偏最小二乘方法(PLS)。研究表明,PLS能有效校正高浓度基体干扰引起的测量误差,比多元光谱拟合法(MSF)能承受的基体浓度更高。当基体与杂质的含量比为1 000∶1～20 000∶1时,该方法的加标回收率在95%～105%之间。对于干扰效应与基体浓度呈非线性相关的体系,普通PLS的预测准确度不高,但使用基于样品浓度矩阵变换的偏最小二乘法(LIN-PPLS),则明显改善了预测的准确度。分别用MSF、普通PLS和LIN-PPLS对水系沉积物国家标准物质GBW07312中的Co,Pb和Ga进行测定,结果表明,LIN-PPLS的预测准确度优于普通PLS,而普通PLS的预测准确度优于MSF。     

POSC-PLS方法及其在电子吸收光谱定量分析中的应用

针对光谱数据局部效应显著,变量个数多,彼此间常存在严重的复共线性,构建了一种基于分段正交信号校正(piecewise OSC)的偏最小二乘(PLS)回归,即POSC-PLS方法。它以近邻分段方式进行逐个波长点的正交信号校正,剔除光谱矩阵中所含的各种噪声信号,将去噪后的光谱矩阵作为新的自变量矩阵,再利用偏最小二乘方法建立校正模型。将该法应用于多环芳香烃电子吸收光谱的多组分定量关系建模,效果良好。所建模型的预报性能优于其他方法,而且模型所需PLS成分数减少,模型更简洁。     

Hydrogenation-induced insulating state in the intermetallic compound LaMg2Ni

Hydrogenation-induced metal-semiconductor transitions usually occur in simple systems based on rare earths and/or magnesium, accompanied by major reconstructions of the metal host (atom shifts >2 A). We report on the first such transition in a quaternary system based on a transition element. Metallic LaMg2Ni absorbs hydrogen near ambient conditions, forming the nonmetallic hydride LaMg2NiH7 which has a nearly unchanged metal host structure (atom shifts <0.7 A). The transition is induced by a charge transfer of conduction electrons into tetrahedral [NiH4]4- complexes having closed-shell electron configurations.     

基于激光诱导击穿光谱技术的咖啡豆中咖啡因含量快速检测方法

应用激光诱导击穿光谱(LIBS)技术研究了快速检测咖啡豆中咖啡因含量的可行性。将咖啡豆磨粉压成片状作为采集LIBS光谱数据的样本,应用原子吸收分光光度计测量每个样本中咖啡因的含量。应用基线校正,小波变换和归一化等数据预处理方法;针对基于全部变量的偏最小二乘(PLS)模型会出现过拟合,分别应用回归系数和主成分分析(PCA)选择特征变量,并建立了基于特征变量的PLS和BP神经网络模型。结果表明：基于回归系数所选特征变量的PLS模型中,建模集相关系数R_c=0.96,预测集R_p=0.91;基于PCA提取特征变量的PLS模型中,R_c=0.94,R_p=0.90;基于PCA所选特征变量的BP神经网络模型中,R_c=0.96,R_p=0.96。两种方法所提取特征变量均对应C,H,O,N,Na,Mn,Mg,Ca和Fe,且基于上述两种方法所选特征变量的PLS模型均对预测集样本有较好的预测结果,说明上述元素与咖啡因含量存在联系,应用回归系数和PCA选择的特征变量是有效的,但是咖啡豆内C,H,O,N,Na,Mn,Mg,Ca,Fe与咖啡因含量的确切关系需要进一步研究。基于PCA所选特征变量的BP神经网络模型有更优的预测结果,说明所选特征变量适用于不同的建模方法。研究表明LIBS技术结合化学计量学方法可以实现咖啡豆中咖啡因含量的快速检测。     

Enhanced electrical resistivity before Néel order in the metals RCuAs2 (R=Sm,Gd, Tb,and Dy)

We report an unusual temperature (T) dependent electrical resistivity (rho) behavior in a class of ternary intermetallic compounds of the type RCuAs2 (R=rare earths). For some rare earths (Sm, Gd, Tb, and Dy) with negligible 4f hybridization, there is a pronounced minimum in rho(T) far above respective Néel temperatures (T(N)). However, for the rare earths which are more prone to exhibit such a rho(T) minimum due to 4f-covalent mixing and the Kondo effect, this minimum is depressed. These findings, difficult to explain within the hitherto-known concepts, present an interesting scenario in magnetism.     

简化苹果糖度预测模型的近红外光谱预处理方法

采用正交信号校正法(OSC)和净分析物预处理法(NAP)分别对苹果的近红外光谱(1300~2100 nm)进行预处理,并结合偏最小二乘法(PLS)建立了糖度预测模型。应用结果显示,随着预处理过程中所用的正交信号校正因子或净分析物预处理因子的逐渐增加,偏最小二乘糖度模型(OSC/PLS模型和NAP/PLS模型)所采纳的最佳因子数也会随之减少,甚至可减至1。当采用10个正交信号校正因子预处理苹果光谱时,OSC/PLS糖度模型达到最佳性能,最佳模型采纳的因子数为2;采用11个净分析物预处理因子预处理光谱时,NAP/PLS糖度模型达到最佳性能,最佳模型采纳的因子数为1。从总体上评价,最佳OSC/PLS糖度模型和最佳NAP/PLS糖度模型的性能都明显优于原始光谱的最佳偏最小二乘模型。这些结果表明,正交信号校正法和净分析物预处理法都能在保证精度的同时有效地简化苹果糖度预测模型。     

A high pressure distorted α-uranium (Pnma) structure in plutonium

Under pressure many rare earths and actinide metals transform to α-U type structure or its lower symmetry distorted forms. We have reinterpreted the diffraction data of Dabos et al. for Pu [S. Dabos et al. J. Alloys Compd. 190 (1993) 237] and find that an Am IV type distorted α-U structure in Pnma space group can explain its high pressure phase. The structures of both the high pressure Am IV type phase and α-Pu, the 0.1 MPa phase, are shown to have a distorted hcp topology. The upturn in the atomic volume of Pu at 0.1 MPa can also be rationalized on the basis of this proposal.     

Thermally stimulated depolarization currents and ionic conductivity of cubic lead fluoride containing small rare earth ions

Abstract

This work is concerned with thermally stimulated depolarization current (TSDC) and ionic conductivity studies in lead fluoride containing the small rare earths Dy, Ho, Er and Yb. The TSDC scans from 80 to 300 K show two peaks. For Pb_1?xEr_xF_2+x one is located at 106 K, and another, which is much stronger, occurs at about 160 K. The former is associated with a dipolar defect containing at least two rare earths and the latter is attributed to the development of F^? space charge during polarization of the sample. The activation energies obtained from both the high temperature TSDC peak and the ionic conductivity are the same, which corroborates the latter assignment. In addition, the ionic conductivity is shown to be independent of concentration. Those results can be understood of rare earth clustering, which is either absent or is unobservable dielectrically for large rare earths such as lanthanum, occurs extensively even at very low concentrations of the small rare earths. The explanation is that the majority of fluorine charge compensators are trapped by clusters.     

稀土掺杂ABS防激光玻璃的制备及其结构研究

在稀土掺杂碱硼硅酸盐(ABS)玻璃形成能力研究的基础上,采用核磁共振NMR、红外激光拉曼光谱等测试手段研究该种玻璃的结构特征。研究结果表明,[SiO4]2-、[BO4]5-和[BO3]3-等结构单元通过[SiO4]4--[BO4]5-、[BO4]5--[BO3]3-、[BO3]3--[SiO4]4-等连接方式构成了玻璃网络结构,形成了巨大的介稳体系,稀土Sm3+等阳离子则填充在网络空隙之中。光谱研究结果表明,Sm3+掺杂ABS玻璃对1.06μm波长的激光具有很强的吸收,当稀土含量达到20mol%时,玻璃在1.06μm波长的透过率仅为0.03%。     

Superposition-model analysis of rare-earth doped BaY 2 F 8

The energy level schemes of four rare-earth dopants (Ce 3+ , Nd 3+ , Dy 3+ , and Er 3+ ) in BaY 2 F 8 , as determined by optical absorption spectra, were fitted with a single-ion Hamiltonian and analysed within Newman's Superposition Model for the crystal field. A unified picture for the four dopants was obtained, by assuming a distortion of the F m ligand cage around the RE site; within the framework of the Superposition Model, this distortion is found to have a marked anisotropic behaviour for heavy rare earths, while it turns into an isotropic expansion of the nearest-neighbours polyhedron for light rare earths. It is also inferred that the substituting ion may occupy an off-center position with respect to the original Y 3+ site in the crystal.