Solution and Thermodynamic Studies on Binary and Ternary Complexes of Lanthanides

The interactions of La(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), Gd(Ⅲ), Dy(Ⅲ), and Yb(Ⅲ) with cytosine, 5-bromocytosine, 5-azacytosine and 5-flurocytosine as primary ligands (L) and guanine (A) as secondary ligand for both binary (1:1) as well as ternary (1:1:1) systems were investigated by potentiometric equilibrium measurements at 25, 35 and 45 ℃ in aqueous solution (ionic strength, μ=0.1 mol·dm-3 NaNO3). The stability constants of the binary (1:1) and ternary (1:1:1) metal-ligand complexes follow the following order La＜Pr＜Nd＜Sm＜Eu＞Gd＜Dy＞Yb. Results also indicate that the ternary lanthanide complexes of La(Ⅲ), Pr(Ⅲ), Nd(Ⅲ), Sm(Ⅲ), Eu(Ⅲ), Gd(Ⅲ), Dy(Ⅲ), and Yb(Ⅲ) are more stable than corresponding binary lanthanide complexes. The enthalpy (Δhof) and entropy (Δsof) changes for the formation of binary and ternary complexes were calculated from temperature coefficient data. The ΔΔSof values are positive for all the metal ligand systems. The negative ΔΔHof values indicate the extra stability of the ternary complexes by the exothermic enthalpy changes (ΔΔSof=ΔTSof-ΔBSof and ΔΔHof=ΔTHof-ΔBHof where ΔTSof, ΔTHof and ΔBSof, ΔBHof are the entropy and enthalpy values associated with the ternary and binary complexes, respectively). It was also proposed that the guanine is bonded to metal ions through N1/C6=O and N7 whereas cytosine and its derivatives are bonded through N3 atoms in ternary complexes.     

Thermodynamic Assessment of Interaction Relation between Lanthanum and Constituent Elements in Sn-Pb Alloy

Ｂｙａｄｄｉｎｇｔｒａｃｅａｍｏｕｎｔｏｆｌａｎｔｈａｎｕｍ(0 0 2 4% ) ,ｔｈｅｍｉｃｒｏｓｔｒｕｃｔｕｒｅｏｆｔｒａｄｉｔｉｏｎａｌＳｎ6 0 Ｐｂ40ｓｏｌｄｅｒａｌｌｏｙｉｓｈｏｍｏｇｅｎｉｚｅｄ ,ｔｈａｔｉｓ ,ｔｈｅｃｏａｒｓｅＳｎ ｒｉｃｈｈａｌｏｗｈｉｃｈｓｕｒｒｏｕｎｄｓｔｈｅｐｒｉｍａｒｙＰｂ ｒｉｃｈｐｈａｓｅｉｓｄｅｐｒｅｓｓｅｄｏｂｖｉｏｕｓｌｙ .Ａｓａｒｅｓｕｌｔ,ｔｈｅｈｉｇｈ ｔｅｍｐｅｒａｔｕｒｅｔｅｎｓｉｌｅｓｔｒｅｎｇｔｈｏｆＳｎ6 0 Ｐｂ40ｓｏｌｄｅｒａｌｌｏｙｉｎｃｒ…     

Phase equilibria calculation of LaI3-MI （M=Na, K, Cs） binary systems

The Gibbs energies of liquid phases in the LaI3-MI (M=Na, K, Cs) systems were described by the modified quasi-chemical model. From the measured phase equilibrium data of these binary systems, a set of thermodynamic functions were optimized by using the CAL-PHAD technique. The enthalpy of mixing and the interaction parameter of the liquid phase were predicted from known data for the LaI3-MI systems.     

Thermodynamic Optimization of TmCl3-ACl （A = Na, K, Rb, Cs）Phase Diagrams

As well known, molten salt electrolysis was wide ly used for the production of rare earth metals andtheir alloys. And, phase diagrams are the most impor tant data for fused electrolytes. Dealing with the bina ry phase diagrams relating to rar…     

Thermodynamic Assessment of DyCl3-MCl （M= Na, K, Rb, Cs） Systems

Using the CALPHAD （Calculation of Phase Diagram） technique, the DyCl3-MCl （M = Na, K, Rb, Cs） systems were optimized and calculated. The modified quasi-chemical model in the pair approximation for short-range ordering was used to describe the Gibbs energies of the liquid phase in these systems. From the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized base on an interactive computer-assisted analysis. The optimized parameters and the experimental data were thermodynamically self-consistent. The optimized results were discussed.     

Hydrogen Absorption Thermodynamic Properties of Rare-Earth Based Hydrogen Storage Alloy in Benzene

Ｔｈｅｐｒｏｐｅｒｔｙｔｈａｔｔｈｅｒａｒｅｅａｒｔｈｂａｓｅｄｈｙ ｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓｃａｎａｂｓｏｒｂ/ｄｅｓｏｒｂａｌａｒｇｅａｍｏｕｎｔｏｆｈｙｄｒｏｇｅｎａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅｈａｓｂｅｅｎｕｓｅｄｓｕｃｃｅｓｓｆｕｌｌｙｆｏｒｈｙｄｒｏｇｅｎｓｅｐａｒａ ｔｉｏｎ ,ｐｕｒｉｆｉｃａｔｉｏｎ ,ａｎｄｔｒａｎｓｐｏｒｔａｔｉｏｎ .Ｉｎｔｈｅａｐｐｌｉｃａｔｉｏｎｓ ,ｉｎｏｒｄｅｒｔｏａｖｏｉｄｐｒｏｂｌｅｍｓｓｕｃｈａｓｔｈｅｏｂｓｔｒｕｃｔｉｏｎｔｏｇａｓ…     

Reaction between Lanthanum and Phosphorus in Steel

P always causes low temperature emhrittlement and temper embrittlement owing to itsgrain boundary segregation[']. Garcia C I etal. [2) reported a complex compound containingLa, O I S and P, in which LaZOZS acted as anucleation site and Fe-P precipitated on thesurface of the oxysulfide. Nevertheless, thermodynamic calculation by Seah M P showedthat La could not react with P in steel unlesstemperature is lower than 1100 T, sinceGibbs free energy of formation of LaP is positive above thi…     

Adsorption of erbium(Ⅲ) on D113-Ⅲ resin from aqueous solutions: batch and column studies

The adsorption and desorption behaviors of Er(Ⅲ) ion on D113-Ⅲ resin were investigated.Batch adsorption studies were carried out with various Er(Ⅲ) ion concentrations,pH,contact time and temperature,indicating that D113-Ⅲ resin could adsorb Er(Ⅲ) ion effectively from aqueous solution.The loading of Er(Ⅲ) ion onto D113-Ⅲ resin increased with increasing the initial concentration.The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.45 to 6.75.In the batch s...     

Thermodynamic optimization and calculation of phase diagrams of YbCl3-MCl (M=Na, K, Rb, Cs)

YbCl3-MCl (M = Na, K, Rb, Cs) systems were optimized and calculated using the CALPHAD (CALculation of PHAse Diagram) technique. The modified quasi-chemical model in the pair-approximation for short-range ordering was used to describe the Gibbs energies of liquid phase in the systems. On the basis of the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized and calculated through an interactive computer-assisted analysis. Furthermore, some reasonable discussions on the thermodynamic parameters for these strong interaction binary systems were carried out. The results showed that the optimized parameters and experimental data are thermodynamically self-consistent.     

相图计算及其应用

综述相图计算方法的发展现状、相图热力学计算常用的相描述模型及常用的热力学计算软件,并以Cu–Fe–Mn和Fe–Mn–Ni体系为例重点介绍相图热力学计算在材料设计及制备中的应用。     

Thermodynamic and Kinetic Study of Crystallization Reaction of Fe/Dy Multilayers Form Amorphous State

ＭａｇｎｅｔｉｃｆｉｌｍｓｏｆＴＭ/ＲＥｃａｎｔｒａｎｓｆｏｒｍｔｏａｍｏｒｐｈｏｕｓｓｔａｔｅｂｙｍｅａｎｓｏｆａｄｊｕｓｔｉｎｇｔｈｅｉｒｍｏｄｕｌａｔｉｏｎｐｅｒｉｏｄｉｃｉｔｙｄｕｒｉｎｇｄｅｐｏｓｉｔｉｏｎ .Ｔｈｅｆｉｌｍｓｉｎａｍｏｒｐｈｏｕｓｓｔａｔｅｅｘｈｉｂｉｔｐｅｒｐｅｎｄｉｃｕｌａｒａｎｉｓｏｔｒｏｐｙａｎｄａｒｅｐｒｏｍｉｓｉｎｇｃａｎｄｉｄａｔｅｓｆｏｒｍａｇｎｅｔｉｃｒｅｃｏｒｄｉｎｇｍｅｄｉａ .Ａｍｏｒｐｈｏｕｓｓｔａｔｅｉｓｔｈｅｒｍｏｄｙｎａｍｉｃａｌｌｙｍｅｔ…     

相图计算技术在复相陶瓷燃烧合成热力学分析中的应用

应用相图计算技术（ＣＡＬＰＨＡＤ）对燃烧合成复相陶瓷的绝热燃烧温度，平衡相组成等进行了热力学分析。讨论了铝热型自蔓延高温合成反应中副产物相的成因及可能的消除途径。根据稀释剂对绝热温度的影响方式提出了稀释作用的两种模式。对反应热压中采用的硼，碳和Ａｌ２Ｏ３体系的绝热温度进行了计算，并对其放热能力进行了评价。     

稀土厂废水的放射性及其净化技术探讨

基于稀土厂废水的放射性,吸取水质放射性污染净化原理与多种粘土矿物和土壤对稀土的吸附性,探讨稀土厂废水放射性的净化技术。建议稀土厂在现有废水处理的基础上,建吸附滤池,通过混合吸附剂对水中放射性元素的吸附,净化废水放射性,确保环境辐射安全性。     

Kinetic and spectral studies of EHPG systems using chemi- and electrochemiluminescence methods

The systems containing EHPG, EHPG-OCH3 and EHPG-NH-Ac and Tb(Ⅲ) ions were used to study chemiluminescence (CL) and electrochemiluminescence (ECL) processes. In the CL studies the Fenton system (Fe(Ⅱ)/(Ⅲ)-H2O2) was used as a source of reactive oxygen species (ROS). Kinetic CL curves and CL spectral distributions were recorded. On the basis of the results obtained, it was demonstrated that Tb(Ⅲ) acted as a sensitizer. Similarly obtained CL decays in the systems of Fe(Ⅱ)/(Ⅲ)-EHPG (or its derivatives)-H2O2 and Fe(Ⅱ)/(Ⅲ)-EHPG (or its derivatives)-Tb(Ⅲ)-H2O2, independently on the Tb(Ⅲ) concentration, showed that the lanthanide ions did not influence the kinetics of the oxidation of EHPG (or its derivatives) in the Fenton systems. The CL intensity increased with the increasing concentration of Tb(Ⅲ) ions, which were the main emitters in the reaction systems. Spectrophotometric and luminescent studies of the systems before and after the additions of hydrogen peroxide proved that the excitation of the lanthanide ion was a result of energy transfer from the excited products of the oxidation of EHPG or its derivatives to the uncomplexed Tb(Ⅲ) ions. ECL was generated on the surface of a nonstructural modified aluminum electrode with the use of K2S2O8, H2O2 or KN3 as coreactants in aqueous solution. In these studies we employed Al electrodes covered with a 2-4 nm layer of Al2O3 doted with Tb(Ⅲ) or Dy(Ⅲ) ions. The electrodes were polarized using cathodic and anodic pulses of various amplitude and frequency. The relative ECL efficiencies were determined as a function of electric pulse parameters, electrolyte compositions and the thickness of barrier or porous layer of the Al2O3 electrode.     

Qualitative Analysis of Relationship between Refractive Index and Atomic Parameters of Solid Materials

The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure and composition of materials. A qualitative relation between the refractive index and some atomic parameters of materials was proposed and demonstrated by some oxide optical crystals. A parameter P = r^-/F=r^-/( r^ ΔxD ) is defined, in which Δx is the difference of the electronegativities between cations and anions in the materials and r^ and r^- are the radii of cations and anions respectively. On the other hand, the factor D was introduced to describe the effect of mass difference of the ions. It is demonstrated by both theoretical discussion and experimental data that refractive index is a decreasing function of parameter P. The relation may be useful for the investigation of optical materials.     

Spectral analysis in ultraweak emissions of chemi- and electrochemiluminescence systems

Investigation of ultraweak emissions in the processes of chemiluminescence, CL, and electrochemiluminesce, ECL, requires special techniques of their recording and spectral analysis. From among the hitherto proposed methods of detection of the emission spectra of these processes, that of the cut-off filter was most sensitive. The usefulness of this method in interpretation of the CL and ECL systems of the quantum yields in the range 1×10⁻⁹−1×10⁻¹¹ containing ions and complexes of Eu(III), Tb(III) and Dy(III) was shown. Exceptional character of the emission bands of lanthanide ions, being a result of the f-f electron transitions and in particular their low FWHM, permitted the application of the cut-off filter method to their analysis. The results obtained for CL and ECL on the basis of analysis of ultraweak emission proved to be successful in analytical applications. The systems containing Eu(III) ions hydrated or complexed with organic ligands enabled inferring changes in the coordination sphere of the ions.     

Effects of Microalloying on Glass Forming Ability and Thermodynamic Fragility of Cu-Pr-Based Amorphous Alloys

The effects of microalloying of Ti and B on the glass formation of Cu60Pr30Ni10Al10-2xTixBx（x = 0, 0.05% （atom fraction）） amorphous alloys was investigated using differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. XRD analysis showed that mieroalloying with 0.05% Ti and 0.05% B improved the glass forming ability （GFA）. The smaller difference in the Gibbs free energy between the liquid and crystalline states at the glass transition temperature （△G1-X（Tg）） and the smaller thermodynamic fragility index （△Sf/Tm, where ASf is the entropy of fusion, and Tm is the melting temperature） after mieroalloying correlated with the higher GFA.     

Thermodynamic modelling of Mn-Y and Mn-Gd systems for application of RE in Mg alloy development

Abstract

Mg alloys are extensively used as light structural materials in the modern industry. Mn and RE (rare earth) metals are effectively used as alloying elements to enhance the properties of Mg alloys. Therefore, the thermodynamic database of those alloys is important in the design and processing of Mg alloys. Critical evaluation and optimisation of all available literature data for the Mn-Y and Mn-Gd systems were conducted to obtain reliable thermodynamic functions of all solid and liquid phases. Recent experimental data were taken into account and the phase diagram and thermodynamic properties were slightly revised for the Mn-Y system and considerably altered for the Mn-Gd one from previous studies. Both systems have quite similar thermodynamic properties and phase diagrams. The systematic trend observed in RE elements for Mn-RE systems is discussed.

On fait un usage considérable des alliages de Mg comme matériaux de construction légers dans l’industrie moderne. Le Mn et les métaux de TR (terre rare) sont utilisés effectivement comme éléments d’alliage pour améliorer les propriétés des alliages de Mg. Par conséquent, les bases de données thermodynamiques de ces alliages sont importantes dans la conception et le traitement des alliages de Mg. On a effectué une évaluation critique et l’optimisation de toutes les données disponibles dans la littérature pour les systèmes Mn-Y et Mn-Gd afin d’obtenir des fonctions thermodynamiques fiables de toutes les phases solides et liquides. On a pris en compte des données expérimentales récentes et l’on a révisé légèrement le diagramme de phases et les propriétés thermodynamiques du système Mn-Y et l’on a modifié considérablement celui du Mn-Gd provenant d’études antécédentes. Les deux systèmes ont des propriétés thermodynamiques et des diagrammes de phases plutôt similaires. On discute de la tendance systématique observée chez les éléments de terre rare des systèmes Mn-TR.     

Researches on preparation and properties of polypropylene nonwovens containing rare earth luminous materials

Polypropylene composite nonwovens containing rare-earth strontium aluminates Sr Al2O4：Eu2＋,Dy3＋ and functional additives were fabricated by the spun-bonded technique.The optical properties, morphology and mechanical properties of the samples were characterized.Results from scanning electron microscopy photographs（SEM） indicated that the surface of the fiber was destroyed by the addition of rare earth luminescent materials lightly but the thickness of the fiber was uniform.Differential scanning calorimetry results showed that pure polypropylene has the double crystallization peak at 162.3 and 165.1 °C.Studies from X-ray diffraction showed that the nonwoven prepared with the luminescent materials contained the α-monoclinic crystal and β crystalline phase.Furthermore, the afterglow properties were tested, which showed that the afterglow curve of the luminous nonwoven was similar to that of strontium aluminate, and the intensity was more intensive than luminous nonwoven at the beginning.The nonwoven fabricated with the luminescent material did not affect the crystal lattice of the polymer making the materials have potential applications in fluorescent lamps and field emission displays（FEDs）.