7 mu m emission between Er3+ and Nd3+ ions was proposed. Intense 2.7 mu m emission was obtained from Nd3+/Er3+ co-doped sodium tellurite glasses due to the efficient energy transfer from Nd3+ to Er3+ ions under 808 nm LD pumping. Meanwhile, strongly decreased 545 nm up-conversion and 1.5 mu m emissions were observed. Additionally, to obtain efficient 2.7 mu m emission, the optimized concentration ratio of Nd3+ to Er3+ was found to be MK-1775 research buy 0.5:1 in present glass

system. Our results suggest that the present Nd3+/Er3+ co-doped sodium tellurite glass might have potential application in mid-infrared lasers. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601353]“
“A new and highly efficient method for determining relative carboxyl group distribution in carboxyl-terminated polybutadiene has been developed using practical synthetic

and analytical techniques. Using oxalyl chloride, samples of carboxyl-terminated polybutadiene were rapidly transformed to acid chlorides that were then chemically derivatized with benzyl alcohol, 4-nitrobenzyl alcohol, and 3,5-dinitrobenzyl alcohol. This provided quick and quantitative BI 10773 conversion to the corresponding benzyl ester derivatives. Each new derivative was fully characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The benzyl ester modified polymers were investigated in detail to determine their relative carboxyl group concentrations. To do this, gel permeation chromatography combined with ultra violet/refractive index dual detection was employed. The 4-nitrobenzyl ester, having the highest extinction factor at 270 nm provided the best UV data for analysis. The ultra violet/refractive

index data of four separate polymer samples were plotted as a function of molecular weight. The data were compared with a theoretical plot (carboxyl group two for all molecular weights) to illustrate the relative carboxyl concentration over the entire molecular weight range. Supplemental characterization of the 4-nitrobenzyl modified polymer was carried out using matrix-assisted laser desorption ionization coupled with time of flight mass spectrometry. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123:691-698, 2012″
“We report on the technology and the electrical properties of two different contact systems on n-GaAs nanowires. Annealed ASP2215 manufacturer Ge/Ni/Ge/Au and Pd/Ge/Au multilayer metallization were investigated. Rapid thermal annealing at temperatures common for identical contact systems on n-GaAs layers is found to be crucial due to an enhanced out-diffusion of the Ga component into the Au contact layer. The maximum annealing temperatures ensuring intact nanowires are 320 degrees C for Ge/Ni/Ge/Au and 280 degrees C for Pd/Ge/Au. The fabricated Pd/Ge/Au contacts reveal a specific contacts resistance of 2.77 x 10(-7) Omega cm(2), which is about one order of magnitude lower compared to the values of Ge/Ni/Ge/Au and also lower than Pd/Ge/Au contacts on bulk material (1.