Electron-phonon coupling in cuprate and iron-based superconductors revealed by Raman scattering

Electron-phonon coupling （EPC） in cuprate and iron-based superconducting systems, as revealed by Raman scat- tering, is briefly reviewed. We introduce how to extract the coupling information through phonon lineshape. Then we discuss the strength of EPC in different high-temperature superconductor （HTSC） systems and possible factors affecting the strength. A comparative study between Raman phonon theories and experiments allows us to gain insight into some crucial electronic properties, especially superconductivity. Finally, we summarize and compare EPC in the two existing HTSC systems, and discuss what role it may play in the HTSC.     

THERMODYNAMIC ANALYSIS AND FORMATION ENTHALPY CALCULATION OF OXYGEN VACANCY DEFECT IN DOPED LITHIUM NIOBATE CRYSTALS

Based on the thermodynamic analysis of oxygen vacancy defects in lithium niobate (LiNbO₃ (LN)) and the data of thermogravimetric experiment, the formation enthalpies of congruent and several rare-earth (RE) doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping with valence-changeable RE ions. The experimental results were discussed and a new reduction process for photorefractive LN crystals at a relatively low temperature was proposed, and the reduction-treated crystals showed good effect in practical use.     

锇胺分子氢配合物的研究进展

由于锇胺分子氢配合物中有特殊的键M(η2 H2 )和特殊的配体 分子氢的存在 ,故而具有丰富的取代化学和特殊的光谱性质。在无机化学、配位化学、生物、医药等方面都有极为广阔的应用前景。本文就此进行了简要的回顾与展望     

SPONTANEOUS TRANSFORMATIONS OF NANOCLUSTERS

It is well-known that nano-systems can have properties which are distinctly different from macroscopic systems. In this study we point out the following specific behaviour: if the particle number is decreased so that the size of the system is in the nanometer-realm, new effects emerge which reflect certain features of biological systems although the system is inorganic in nature. This behaviour is shown by realistic molecular dynamics calculations in connection with aluminum-nanoclusters at various temperatures. The clusters can transform without external influence from a metastable into a stable state, and there can be more than one stable state, that is, we observe a bifurcation in the sense of chaos-theory. The stable states can differ in both the atomic structure and the outer shape.     

Determining the main thermodynamic parameters of caffeine melting by means of DSC

The temperature and enthalpy of the melting of caffeine, which are 235.5 ± 0.1°C and 19.6 ± 0.2 kJ/mol, respectively, are determined by DSC. The melting entropy and the cryoscopic constant of caffeine are calculated.     

Extraction of lanthanides(III) by phosphorylated naphthyridine ligands from carbonate solutions

The extraction capacities and selectivities of 1,8-naphthyridine-based neutral organophosphorus reagents in extracting trivalent lanthanides (Ln, Nd, Ho, Yb) from carbonate solutions were studied. The length and nature of the linker between the naphthyridine and phosphoryl moieties were found to have considerable influence on the efficiency and selectivity of lanthanide extraction.     

Gibbs energy increment and minimum work of separation during the distillation of a dilute solution in a multistep cascade

The Gibbs energy increment during the distillation of a dilute solution in a separation cascade was calculated. An interpretation of the minimum work thermodynamically required during the symmetric separation of a binary mixture is suggested.     

Efficiency of electrochemical amination of anisole in aqueous-organic solutions of 4 M H2SO4

Cathodically initiated amination of anisole has been performed with the Ti(IV)-NH₂OH system in aqueous solutions of 4 M H₂SO₄ containing high concentration of acetic acid or acetonitrile. In electrolyses performed to reach full conversion of hydroxylamine, the isomeric anisidines obtained (2 para/ortho ∼ 3.9) with total yields referred to the current and amino radical source exceeded 80%.     

Polymeric ytterbium(ii) complex with pyridyl amido ligands

The reaction of potassium pyridyl amido ligand {L = [N(R)(2-C5H3N-6-Me)]–, R = CH2But} with YbI2(thf)2 afforded the linear polymeric complex [K0.5(L)3YbiiK0.5]n, which was characterized by X-ray structure analysis.