Synthesis of GdB6 nanostructures using nanosecond (Nd: YAG) laser: field emission investigation
We herein report field emission characteristics of GdB6 nanostructures grown directly on a pellet via laser processing (laser fluence ~ 6 J/cm2). The laser processed GdB6 pellet was characterized by X-ray diffraction, which revealed no change in phase upon laser processing. The values of the turn-on field required to draw emission current density of 1 μA/cm2 is found to be ~ 2.95 V/μm, for the laser processed GdB6 emitter. Furthermore, the Fowler-Nordheim (F-N) plot exhibits nonlinear behavior over the entire range of applied field and the field enhancement factor (β) calculated from slope of the F-N plot (low field region) was found to be ~ 543. The emission current stability over a period of 3h was observed to be fairly good. The observed results demonstrate that laser processing can be efficiently used to make GdB6 nanostructure emitter having potential for practical applications.
Single-crystalline GdB6 nanowire field emitters.
Having the lowest work function in the rare-earth hexaboride family, GdB6 nanowires of rectangular cross-section with about 50 nm in lateral dimension and several microns in length have been successfully produced using a CVD method. The nanowires are grown in the 001 lattice direction, and both the tip-top and the side surfaces are terminated with the {100} lattice planes. A GdB6 single nanowire field emitter has also been built with an emission current of more than 150 nA at an applied field of less than 3.2 V/mum. The work function of the nanowire emitter was estimated to be about 1.5 eV.
Aristocratic Century: The sinews of power: political
In his excellent book on the Secretaries of State, Mark Thomson offered ‘the paradox of continuing domination of the aristocracy and the simultaneous insignificance of the House of Lords, per se ’. It is true that, by the beginning of the eighteenth century, the supremacy of the House of Commons in financial matters was a wellestablished convention. The claims of the Commons to an undisputed control over money matters, which had been urged before the Civil War, were resumed immediately after the Restoration and a protracted dispute with the House of Lords began. In 1661 the Lords resolved that there were no precedents in history for this new claim by the House of Commons. In 1671, the Commons retorted that taxation ought not to be questioned by the Lords and in 1678 they reiterated that supply was ‘the undoubted and sole right of the Commons’ and ‘ought not to be changed or altered by the House of Lords’. The Lords' attempt in 1692 to assess their own taxes was also abandoned, though they retired under cover of a rather insubstantial smoke-screen that they maintained their power of amendment to be a ‘fundamental, inherent and undoubted right from which their lordships can never depart’. That established, they departed. Geoffrey Holmes quotes a nice example from 1702 when the bishop of Carlisle found himself the only peer answering to a money bill, ‘no other lord in the House regarded what was doing, this being only (pro forma) to preserve a seeming right to dissent from, or amend, any part of a money bill’.