Identification and quantitative determination of some inorganic lanthanide compounds by diffuse reflectance spectroscopy

Diffuse reflectance spectroscopy in the UV, visible, and near-IR regions is found to allow the detection and identification of lanthanide oxides, fluorides, sulfides, and sulfofluorides without decomposing and dissolving samples. A nondestructive method for the detection and quantitative determination of more than 1 wt % of Eu(II) in the corresponding fluorides is proposed.     

Non-integrability of some Painlevé VI-equations and dilogarithms

The paper studies the Painlevé VI^e equations from the point of view of Hamiltonian nonintegrability. For certain infinite number of points in the parameter space we prove that the equations are not integrable. Our approach uses recent advance in Hamiltonian integrability reducing the problem to higher differential Galois groups as well as the monodromy of dilogarithic functions.      

Low-temperature hydrodechlorination of 2,3-dichlorodibenzo-p-dioxin and chlorobenzene with hydrides catalyzed by transition metal compounds

Hydrodechlorination of chlorobcnzene by chemically bound hydrogen in the presence of transition metal compounds was studied. Alkali and alkaline earth metal hydrides (NaH, MgH₂, LiAlH₄, NaH(LiAlH₄)/12) were used as the sources of the chemically bound hydrogen. The effect of the natures of the hydride and of the transition metal on the activity was studied under comparable conditions. The Pd/C-NaH(LiAlH₄1/2 catalytic system was found to be the most active. This system made it possible to perform the quantitative dechlorination of 2,3-dichlorodibenzo-p-dioxin at 70 °C.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1391–1394, June, 1996.     

Specific Features of Glucoamylase Immobilization by Adsorption on Fibrous Polyelectrolytes

Some fundamental aspects of the immobilization of a hydrolytic enzyme glucoamylase via adsorption on aminocarboxylic ion-exchangers with fibrous structure were considered. The sorption capacity of amphoteric supports for the enzyme was studied in relation to the time of immobilization, concentration of hydrogen ions and the protein, and the ionic form of a polyelectrolyte. The catalytic properties of free and immobilized enzymes were compared.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 1003–1005.Original Russian Text Copyright © 2005 by Shkutina, Stoyanova, Selemenev.     

Coordination compounds of Co(II), Ni(II), and Cu(II) valerates and benzoates with semicarbazide

Complexes of Co(II), Ni(II), and Cu(II) valerates and benzoates with semicarbazide were prepared. The compounds were characterized by chemical analysis, X-ray phase analysis, IR spectroscopy, diffuse reflection spectroscopy, and thermal gravimetric analysis.     

Spectroscopic and computational investigation of the ground and low excited states of some symmetrical heterocyclic disulfides

The electronic absorption and emission spectra of some symmetrical heterocyclic disulfides are investigated. The reversible disulfide — thione transformation in water is discussed in view of the complex equilibrium processes present. UV irradiation and pH influence on the above transformation is also studied. The emission properties at room and low temperature are related to the computed molecular geometries of the ground and low excited states of the compounds.     

Molecular Engineering of Quinone-Based Nickel Complexes and Polymers for All-Organic Li-Ion Batteries

All-organic Li-ion batteries appear to be a sustainable and safer alternative to the currently-used Li-ion batteries but their application is still limited due to the lack of organic compounds with high redox potentials toward Li⁺/Li⁰. Herein, we report a computational design of nickel complexes and coordination polymers that have redox potentials spanning the full voltage range: from the highest, 4.7 V, to the lowest, 0.4 V. The complexes and polymers are modeled by binding low- and high-oxidized Ni ions (i.e., Ni(II) and Ni(IV)) to redox-active para-benzoquinone molecules substituted with carboxyl- and cyano-groups. It is found that both the nickel ions and the quinone-derived ligands are redox-active upon lithiation. The type of Ni coordination also has a bearing on the redox potentials. By combining the complex of Ni(IV) with 2-carboxylato-5-cyano-1,4-benzoquinones as a cathode and Ni(II)-2,5-dicarboxylato-3,6-dicyano-1,4-benzoquinone coordination polymer as an anode, all-organic Li-ion batteries could be assembled, operating at an average voltage exceeding 3.0 V and delivering a capacity of more than 300 mAh/g.     

Cherenkov counter for measuring the intensity of bunches extracted from the IHEP accelerator

The Cherenkov counter for measuring the numbers of protons in bunches extracted from the IHEP accelerator using a slow extraction system is described. The measurement range is from 1 to 10⁶ particle/bunch. The maximum bunch frequency is 6 · 10⁶ s^–1. Cherenkov light is measured by an XP 2020 photomultiplier. The results of measurements of the XP 2020 signal amplitude on the applied voltage, obtained using semiconductor light sources are presented. The data of counter calibration on the proton beam are discussed.