The ionic conductivity of rapidly quenched tungstate and molybdate glasses containing lithium halides

Rapidly quenched lithium tungstate and molybdate glasses containing up to 20 mole% lithium chloride and bromide additives have been prepared. The additives are found to give a small increase (up to a factor of two at room temperature) in the lithium ion conductivity of the glass which can be understood in terms of models developed for network forming glasses.     

Photorefractive effects for reversible holographic storage of information

Optical storage of information offers great potential for high capacity and speed. A very promising approach to the embodiment of an optical memory is based on volume storage in the form of phase holograms. Attractive storage materials for such a system are electrooptic crystals. The storage mechanism in these materials is based on light induced permanent changes of the refractive index-the photorefractive effect. In this article the physical processes underlying photorefractive hologram recording are outlined, and some of the advantages and limitations of this method are discussed.     

A comparison of local search methods for flow shop scheduling

Local search techniques are widely used to obtain approximate solutions to a variety of combinatorial optimization problems. Two important categories of local search methods are neighbourhood search and genetic algorithms. Commonly used neighbourhood search methods include descent, threshold accepting, simulated annealing and tabu search. In this paper, we present a computational study that compares these four neighbourhood search methods, a genetic algorithm, and a hybrid method in which descent is incorporated into the genetic algorithm. The performance of these six local search methods is evaluated on the problem of scheduling jobs in a permutation flow shop to minimize the total weighted completion time. Based on the results of extensive computational tests, simulated annealing is found to generate better quality solutions than the other neighborhood search methods. However, the results also indicate that the hybrid genetic descent algorithm is superior to simulated annealing.     

Synthesis and characterization of the first trimetallic nitride templated pyrrolidino endohedral metallofullerenes

New pyrrolidino derivatives of both diamagnetic and paramagnetic trimetallic nitride templated endohedral metallofullerenes were synthesized by the Prato reaction, isolated and characterized by means of MALDI-TOF MS, NMR and UV-vis spectroscopies.     

Universality and self-similarity in the bifurcations of circle maps

The bifurcation structure in a two-parameter family of circle maps is considered. These maps have a (topological) degree that may be different from one. A generalization of the rotation number is given and symmetries of the bifurcations in parameter space are described. Continuity arguments are used to establish the existence of periodic orbits. By plotting the locus of parameter values associated with superstable cycles, self-similar bifurcations are found. These bifurcations are a generalization of the familiar period-doubling cascade in maps with one extrema, to two-parameter maps with two extrema. Finally, a scheme for the global organization of bifurcation in these maps is proposed.     

Neutron spectra at 0° from (p,n) reactions on 9Be, 12C,and 27Al at 647 and 800 MeV

The measured cross sections show a narrow high-energy peak (20–30 MeV/cFWHM) and a broad bump at lower momenta associated with pion production. Comparison is made to an intranuclear cascade calculation.     

A multielectrode microcompartment culture platform for studying signal transduction in the nervous system

This paper describes the design, fabrication, and characterization of a microfabricated compartmented culture system (micro-CCS) useful for electrophysiological signaling studies in cultured neurons. The focus of the paper is the process of interfacing the micro-CCS with cultured neurons and to demonstrate the applicability of the system for biochemical-mediated electrophysiological studies. Moreover, we show that we can record action potentials from cultured neurons through the extracellular compartmented application of elevated levels of K(+) ions. Finally, we show that we can isolate the electrophysiological effects of the sodium channel blocker tetrodotoxin in one of the compartments of a two compartment culture while recording electrophysiological data from both compartments.