Microwave enhanced solvent-free synthesis of a library of quinoline derivatives

A minilibrary of 12 quinoline derivatives was synthesized in the presence of 0.1-0.5 equiv. of diphenylphosphate without any solvents. Each compound was obtained with high yield in 4 min of microwave irradiation.     

Decision analysis models in reinsurance

Decision analysis models are developed and illustrated for the reinsurance (risk transfer) decisions made by insurance companies. Decision analytic models were found to be useful tools both for structuring multistage reinsurance decisions and for comparing alternative options. The insurer is faced with many possible choices involving reinsurance type and extent, and an expected utility model provided insight both as a screening device and as an evaluation criterion. Decision analytic models appeared to be superior to other approaches such as mean/variance and risk of ruin models both because of their flexibility and their more comprehensive treatment the important elements of the decision, namely the complete claims distribution, the cost of reinsurance and the insurer's risk attitude.     

A thermally stable polymer molecular composite

A molecular composite of rigid-rod poly(p-phenylene benzobisthiazole) and flexible-coil poly(benzimidazobenzophenantroline) has been prepared, characterized, and shown to be thermally stable to at least 300°C. These results suggest that stable miscible blends of rodlike and coil-like polymers can be prepared by controlling the glass transition temperature of the flexible-coil polymer. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of La0.9Sr0.1Ga0.8Mg0.2O3-δ electrolyte for intermediate temperature solid oxide fuel cells (ITSOFC)

Experimental investigations on new materials for application as electrolyte in electrolyte supported planar Intermediate Temperature Solid Oxide Fuel Cells (ITSOFC) operating below 800 °C is in progress at our laboratory. Sr and Mg doped Lanthanum gallate (LSGM) powder was prepared by glycine — nitrate combustion method. The prepared LSGM powder is relatively finer than that prepared through other techniques such as solid-state reaction. The measurements comprising XRD, particle size, density, TGA/DTA were made. Thin sections of circular pellets were fabricated and annealed at different temperatures ranging between 1000 and 1300 °C. The sintering behaviour of LSGM was investigated to obtain information on the densification factor, relative percentage shrinkage/expansion in volume, while annealing and the resulting apparent porosity values. Bismuth oxide is found to be an effective sintering aid in general. So the effect of bismuth oxide addition on LSGM was investigated through sintering studies, XRD, TGA/DTA, SEM and conductivity measurements. The results obtained on LSGM with and without bismuth oxide addition are discussed with respect to the requirement of an electrolyte for ITSOFC applications. Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003.     

Observation of surface and bulk plasmons in semiconductor superlattices

We report far infrared measurements of oblique incidence power reflectivity and attenuated total reflection (ATR) on multiply Si δ-doped GaAs samples. The reflectivity spectrum in s-polarisation probes the in-plane component of the superlattice dielectric function, and is sensitive to the overall 3D electron density. The p-polarisation spectrum, however, also probes the out-of-plane component, resulting in an extra mode which is sensitive to the distribution of free electrons between wells and barriers. The p-polarisation ATR spectrum shows surface modes which are also sensitive to this distribution. The results are compared with a bulk slab model of the dielectric function.     

The Series of Norms in a Soluble p-Group

The norm of a group G is the subgroup of elements of G whichnormalise every subgroup of G. We shall denote it (G). An ascendingseries of subgroups _i(G) in G may be defined recursively by:₀(G) = 1 and, for i 0, _i+1(G)/_i(G) = (G/_i(G)). For each i,the section _i+1(G)/i(G) clearly contains the centre of the groupG/_i(G). A result of Schenkman [8] gives a very close connectionbetween this norm series and the upper central series: _i(G) _i(G) _2i(G). 1991 Mathematics Subject Classification 20E15.     

Properties of dysprosium-doped gallium lanthanum sulfide fiber amplifiers operating at 1.3 microm

In light of recent progress in the fabrication of gallium lanthanum sulfide (GaLaS) fibers, we have modeled the performance of dysprosium-doped GaLaS fiber amplifiers operating at 1.3mum . Based on experimental data, we find that the incorporation of a codopant (terbium) in the fiber core significantly shortens the optimum amplifier length from >30 m to ~3 m . Such a device may be practical, given the fiber losses currently achieved in GaLaS fibers.     

Synthesis and Downstream Reactions of 2-(Triphenylphosphino)-4,5-dicarbomethoxy-1,3-diselenole Tetrafluoroborate: X-ray Crystal Structure of a Nitroso Derivative of a 2-Ylidene-1,3-diselenole Stabilized by an Intramolecular O.Se Interaction

The title 1,3-diselenole Wittig reagent 9 has been synthesised by a new, efficient route from readily-available starting materials and reacted with a variety of functionalized aldehydes to form the corresponding 2-ylidene-1,3-diselenones 12 in respectable yields. X-ray analysis of a nitrosated derivative 14e, prepared by the reaction of 12e with isoamyl nitrite, has provided the first direct evidence for the stabilization of such systems by intramolecular oxygen-selenium interactions.