Quasielastic neutron scattering study of hydrogen motion in NbC0.71H0.28
In order to study the mechanism and parameters of H jump motion in the nonstoichiometric Nb carbides, we have performed quasielastic neutron scattering (QENS) measurements for NbC0.71H0.28 over the temperature range 11– 475 K. Our results indicate that about 30% of H atoms in this system participate in a fast diffusive motion. The temperature dependence of the corresponding H jump rate in the range 298–475 K follows the Arrhenius law with an activation energy of 328 ± 9 meV. The Q dependence of the QENS data suggests that the observed jump motion corresponds to long-range diffusion of H atoms along chains of the off-centre sites in carbon vacancies.
Disorder and order in strongly nonstoichiometric compounds : transition metal carbids, nitrides and oxides
1 Introduction.- 2 Crystal Symmetry.- 3 Strongly Nonstoichiometric Compounds.- 4 Short-Range Order.- 5 Long-Range Order.- 6 Interrelation of Short- and Long-Range Orders.- 7 Nonstoichiometric Nitrides at High Temperature.- 8 Order-Disorder Phase Transformation Theories.- 9 Order-Parameter Functional Method.- 10 Equilibrium Phase Diagrams.- 11 Effects of Ordering on the Properties of Strongly Nonstoichiometric Compounds.
Mutiny Echoes: India, Britons, and Charles Dickens's A Tale of Two Cities
This essay asks what, if any, import the Indian ““Mutiny”” of 1857 had on A Tale of Two Cities (1859), Charles Dickens�s fictionalized account of the French Revolution. Begun shortly after the Indian uprising started, Dickens�s historical novel appears studiously to avoid any mention of events on the Indian subcontinent, even though these events preoccupied and enraged the author. Few scholars have attended to the question of A Tale of Two Cities and the ““Mutiny,”” but when they have, scholars have looked for analogies between India and Dickens�s account of the French Revolution. In this essay, by contrast, I examine A Tale of Two Cities in a larger context——of Britons9 response to the Uprising, of Dickens9s short stories and essays in Household Words in the years before the ““Mutiny”” and immediately after, of Dickens9s disenchantment with aspects of British culture, and of his need to articulate a national identity grounded in action. I argue that the events in India were the match that ignited Dickens9s already established midcentury interests in national identity, nobility, and masculine heroism. I do not wish to suggest that A Tale of Two Cities is an Indian ““Mutiny”” novel, but rather that it is a novel about the ““Making of Britons,”” an important endeavor for an author who was intensely dissatisfied with the Britain that he saw around him.