A low crosstalk microoptic liquid crystal switch

A total internal reflection liquid crystal optical switch has been developed which gives crosstalk levels of -33 dB and switching speeds of 4 ms, with low operating voltage. A novel architecture for larger switch arrays is also proposed and prototype device constructed and tested. The effects of modulation on the optical carrier by the electrical drive signal, and methods of minimizing its effect are reported. Finally, a novel space-saving architecture is proposed and demonstrated for 4×4 switch arrays and its performance reported     

In-beam spectroscopy of 126Ce and 127Pr

High spin states in ₁₂₆Ce and ₁₂₇Pr were populated via heavy ion reactions with 182-MeV ₃₅Cl projectiles on a thick ₉₆Ru target. Prompt γ–γ coincidences were measured. New states in ₁₂₆Ce and ₁₂₇Pr were found. The results are discussed in the framework of the core–quasiparticle coupling model. Received: 16 June 1998     

Determination of ammonia in ethylene using ion mobility spectrometry.

A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated.     

Contributions to group IV organometallic chemistry: IX. The effect of ring size on silicon-29 NMR shifts in silicon heterocycles

Silicon-29 NMR shifts for a series of 2,2-diphenyl-1,3,2-dioxasilacycloalkanes are reported and reveal a clear dependence of shift on ring size for rings of 5–14 atoms.     

Transition-Metal Complexes with Bidentate Ligands Spanning trans-Positions. I. The synthesis of 2,11-bis(diphenylphosphinomethyl)benzo[c]-phenanthrene,a ligand promoting the formation of square planar complexes

The bidentate ligand 2,11-bis(diphenylphosphinomethyl)benzo[c]phenanthrene ( 1 ) was synthesized from 2,11-dimethyl-benzo[c]phenanthrene ( 3 ) via the corresponding bromomethyl derivative 9. 3 was obtained from the cyclization with boron trifluoride etherate of 1,1-di-(p-methylphenethyl)-epoxyethane ( 7 ), which was prepared from 1,5-di(p-tolyl)-pentan-3-one ( 6 ).