The use of charged particle bombardment for studying oxygen self-diffusion in oxides

The various nuclear techniques which have been used to study oxygen self-diffusion in oxides are discussed. Results are given for measurements using resonance capture in the¹⁸O(p, α)¹⁵N and¹⁸O(p, γ)¹⁹F reactions and the different techniques are compared.     

Mass spectrometry of 1,1′-diacetylferrocene and 1,1′-dipropionylferrocene: Evidence for intraannular interaction between alkanoyl substituents

The mass spectra of 1,1′-diacetylferrocene, 1,1′-dipropionyl ferrocene and their deuterium and Fe⁵⁷ isotope labeled analogs are herein reported and discussed. Fragmentation pathways are established and evidence is presented that in the process of fragmentation there is extensive interaction between substituents on the two ferrocene rings. This process apparently has little precedent in the mass spectrometry of ferrocene derivatives. Specifically, the experimental results suggest the simultaneous elimination of two molecules of carbon monoxide, or in another case, of carbon monoxide and ethylene from ions produced in the mass spectrometry of the above compounds.     

A tensiometric study of diamond (111) and (110) faces

Tensiometric contact angle measurements of diamond surfaces in both the air:water and octane:water systems reveal moderate hydrophobicity, as might be expected of a surface with a minority of oxygen-containing groups. High-temperature reaction with oxygen or hydrogen leads to large changes in the contact angles. Spectroscopic methods show a “one-third” coverage by oxygen. The response to pH and adsorption of ferric ion suggests that the oxygen is present as an hydroxyl group. Steric resistance to higher oxide coverage, because of the small lattice constant of the crystal, may be an explanation for the natural hydrophobicity of the diamond surface.     

A Single Thermoresponsive Diblock Copolymer Can Form Spheres,Worms or Vesicles in Aqueous Solution

It is well‐known that the self‐assembly of AB diblock copolymers in solution can produce various morphologies depending on the relative volume fraction of each block. Recently, polymerization‐induced self‐assembly (PISA) has become widely recognized as a powerful platform technology for the rational design and efficient synthesis of a wide range of block copolymer nano‐objects. In this study, PISA is used to prepare a new thermoresponsive poly(N‐(2‐hydroxypropyl) methacrylamide)‐poly(2‐hydroxypropyl methacrylate) [PHPMAC‐PHPMA] diblock copolymer. Remarkably, TEM, rheology and SAXS studies indicate that a single copolymer composition can form well‐defined spheres (4 °C), worms (22 °C) or vesicles (50 °C) in aqueous solution. Given that the two monomer repeat units have almost identical chemical structures, this system is particularly well‐suited to theoretical analysis. Self‐consistent mean field theory suggests this rich self‐assembly behavior is the result of the greater degree of hydration of the PHPMA block at lower temperature, which is in agreement with variable temperature ¹H NMR studies.     

5,5-Diaryldipyrromethanes: syntheses and anion binding properties

A two-step synthesis of 5,5-diaryldipyrromethanes in good yields is described. The adopted synthetic strategy can be used to tune the substituent at the meso-carbon very easily by choosing the Grignard reagent of interest. Further, the influence of the incorporation of various diaryl units at the meso-carbon atom in the inherent anion binding affinities of the dipyrromethanes through hydrogen bonding was discussed.     

Fusion research and international scientific collaboration

Many of the oxides and chalcogenides formed by the 3d transition metals and 4f rare-earth metals are antiferro-, ferri-and ferromagnetic semiconductors. In this review, several theoretical aspects of these materials are discussed, including electron correlation in narrow bands and the formation of electrostatic and magnetic polarons. The problems of crystal growth and physical measurement are briefly considered, together with recent studies on the conduction mechanism in typical compounds like NiO, MnO, ferrites, garnets, CdCr₂Se₄ and EuS. Finally, we comment on possible applications.