The Thames

Richard MacCormac evokes the Thames' defining relationship with London, as the boundary between north and south, the primacy of the north bank having remained almost unchallenged until the 21st century with the development of Tate Modern and the rejuvenation of the south bank. Copyright © 2012 John Wiley & Sons, Ltd.     

Design and Implementation of a Technique for Iterative Magnetorheological Jet Polishing

This article introduces a technique for iterative high precision freeform lens polishing, with operations alternating between a fabrication and a measurement unit. The technique is implemented using a Magnetorheological Jet Polishing (MJP) machine as fabrication unit, and a sub-aperture stitching interferometric system as measurement unit. The two units are separately located and have different internal coordinate references. Precision integration of the two is the key to realize high performance iterative polishing. In our study, application of the proposed technique yields a peak to valley (PV) value of 1/7λ in polishing flat optical elements.     

Blue light-emitting diodes from mesogen-jacketed polymers containing oxadiazole units

A series of novel mesogen-jacketed polymers, poly{2,5-bis[(5-tert-butylphenyl)-1,3,4-oxadiazole]styrene} (P-Ct) and poly{2,5-bis[(5-alkoxyl-phenyl)-1,3,4-oxadiazole]styrene} (P-OCn, n is the number of carbons in the alkoxyl groups, n = 6, 8, 10, 12, 14), were incorporated into polymer light-emitting device as the light-emitting layers. All of the polymers had excellent solubility in common organic solvents. The UV and PL spectra for P-Ct were 312 and 400 nm while for P-OCn they were around 328 and 420 nm in the film. There was no red shift in the PL spectrum of P-Ct after heat treatment which maybe related to the jacketed structure. All of the polymers showed high PL quantum yields in THF solution. From the cyclic voltammetry measurement at room temperature, HOMO levels of the polymers were varied from −5.66 to −6.12 eV, LUMO levels were varied from −2.45 to −2.81 eV. Furthermore, the influence of the alkoxyl lengths in four different device configurations was compared. For the device configuration c: ITO/PVK/P-OC8/Ca/Ag, the maximum luminance and maximum external quantum efficiency were obtained for P-OC8 which maybe related to the easier electron injection and transport. Efficiency of P-OC8 was not improved with device d which proved the electron transporting characteristics of P-OC8.