Structural characterization for the chemically Li ion extracted LiyCoO2, LiyCo0.95Ga0.05O2, and LiyCo0.9Ga0.1O2 compounds

Chemical Li ion extraction processes have been carried out for pristine LiCoO₂, LiCo_0.95Ga_0.05O₂, and LiCo_0.9Ga_0.1O₂ compounds by swirling them in 0.35 M H₂SO₄ solution. It is confirmed from XRD patterns that the compounds maintain the two-dimensional framework with pristine-type structure even after the acid treatment up to 12 h. The Ga-substituted compounds keep Li ions for longer time on the acid treatment rather than the LiCoO₂. The average oxidation state of Co ions increases with the Li⁺ ion extraction time up to 3.45+. The local structure refinements for the chemically Li⁺ ion extracted compounds have been investigated by Co K-edge X-ray absorption spectroscopy. The extraction causes the increase of Debye-Waller (DW) factor or static disorder around the Co ion. The DW factor of the Co-Co bond pair less increases with the extraction time for the Li_yCo_0.95Ga_0.05O₂, and Li_yCo_0.9Ga_0.1O₂ compounds than that for the LiCoO₂. The Ga-substituted compounds are more stable against acid treatments than the LiCoO₂, since more basic Ga³⁺ ion retards the structural distortion of the CoO₆ octahedra against the Li ion extraction.     

Crystallographic report: [(Pyridine)(1,2‐bis(2‐pyrazinecarboxamido)‐4,5‐dimethylbenzene)zinc(II)] monohydrate

The N₄ donor ligand, Me₂bpzb^2? and a pyridine molecule are coordinated to the Zinc(II) so that the coordination geometry closely resembles a square‐pyramidal environment with a nitrogen atom of the pyridine ligand occupying the apical position. Copyright © 2003 John Wiley & Sons, Ltd.     

Characteristics of a single‐layered organic electroluminescent device using a carrier‐transporting copolymer and a nonconjugated light‐emitting polymer

We have synthesized a novel carrier‐transporting copolymer and a nonconjugated light‐emitting polymer. The carrier‐transporting copolymer has a triphenylamine moiety as a hole‐transporting unit and a triazine moiety as an electron‐transporting unit, both of which are located in the polymer side chain. The nonconjugated light‐emitting polymer has a perylene moiety, which acts as an emitting unit in the polymer side chain. These polymers are very soluble in most organic solvents, such as monochlorobenzene, tetrahydrofuran, chloroform, and benzene. A single‐layered electroluminescent device consisting of ITO/copolymer and emitting‐material 4‐(dicyanomethylene)‐2‐methyl‐6‐(4‐dimethylaminostyryl)‐4H‐pyran (DCM) or light‐emitting polymer)/Al mixtures exhibits maximum external quantum efficiency when the concentration of the emitting material is 30 wt %. The device emits red or blue light according to the emitting material. When CsF is used as the electron‐injecting material, the drive voltage decreases drastically to 7 V, and the highest quantum efficiency is 0.5%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2733–2743, 2003     

Nitroimino-tetrazolates and oxy-nitroimino-tetrazolates

Highly energetic 1,1'-ethylenebis(oxy)bis(5-nitroimino-tetrazolate) salts were obtained by reacting equimolar quantities of the acidic 1,1'-ethylenebis(oxy)bis(5-nitroimino-tetrazole) and energetic bases in aqueous solution. Additionally, metathesis of silver 1,1'-ethylenebis(oxy)bis(5-nitroimino-tetrazolate) with diaminoguanidinium chloride or triaminoguanidinium chloride gave the corresponding oxy-nitroimino-tetrazolate salt. These salts were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC), and, in some cases, 2·2H(2)O, 8·2H(2)O, 10, 13·2H(2)O and 14, with single crystal X-ray structuring. The heats of formation for all compounds were calculated with Gaussian 03 and then combined with measured densities to determine detonation pressures (P) and velocities (D) of the energetic materials (Cheetah 5.0). The impact sensitivities of all salts were found to be less than those of the parent compounds. The physical and detonation properties of these oxy-nitroimino-tetrazolate salts are comparable to the analogous newly prepared diaminoguanidinium and triaminoguanidinium 1,1'-ethylenebis(5-nitroimino-tetrazolate)s.     

Resistance of β-casein at the air-water interface to enzymatic cleavage

X-ray reflectivity from an air-buffer interfacial β-casein monomolecular film placed on a solution of chymosin (renin) showed unexpectedly slow proteolytic cleavage. To understand this, the separate structures of β-casein and chymosin, the presentation of each molecule to the other at the air/liquid interface, and that of their mixtures is reported. At the air/solution interface, the hydrophobicity of the protein molecules causes orientation and some deformation of the conformation. When β-casein was presented to a chymosin monomolecular interfacial film, the chymosin was largely displaced from the surface, which was accounted for by the different surfactancy of the two molecules at 25 °C. There was no observable proteolysis. In the reverse experiment, a significant enzymatic degradation and the signature of hydrophobic fragments was observed but only at and above an enzyme concentration of 0.015 mg/mL in the substrate. For comparison, the air/solution interface of premixed β-casein with chymosin in phosphate buffer showed that the film was composed of β-casein proteolytic fragments and chymosin.     

Facile fabrication of networked patterns and their superior application to realize the virus immobilized networked pattern circuit

A facile route to fabricate a protein-immobilized network pattern circuit for rapid and highly sensitive diagnosis was developed via the evaporation directed impromptu patterning method and selective avian influenza virus (AIV) immobilization. The response to the 10 fg mL(-1) anti-AI antibody demonstrates that this easy and simple circuit has about 1000 times higher sensitivity compared to those of conventional approaches.