This paper presents work aimed at optimizing the fabrication of silicon nitride Si(x)N(y) thin-film visible-light planar waveguides using plasma-enhanced chemical vapour deposition (PECVD). The effects of plasma frequency, precursor gas ratio, and thermal annealing in relation to waveguide optical properties (refractive index, propagation losses) are studied. Experimental results over a wide ra...

1. Introduction Mesoporous UL-ZSM-5 materials have zeolitic structure in the form of nano-particles inter-grown in the walls of the amorphous wormhole-like aluminosilicate mesoporous precursor, and were shown to exhibit an intermediate acidity between the parent mesoporous precursor and ZSM-5 zeolite [1,2]. These materials combine the advantages of both, i.e., microporous crystalline zeolites (...

1. Introduction In recent years there has been an increasing number of applications requiring more efficient and lightweight thermal management such as high-density electronics, hybrid diesel-electric vehicles, communication satellites, and advanced aircraft. The primary concerns in these thermal management applications are high thermal conductivity, low weight, low coefficient of thermal expan...

in this paper, we report on the synthesis of cu nanoparticles through a single-precursor route by controlling the growth temperature. selective adsorption of oleylamine on various crystal planes may play an important role in the growth process. the understanding of this self-assembling process will help us develop reliable and reproducible methods to synthesis other three dimensional nanostruct...

The possible presence of thermal components in the early X-ray afterglows of γ-ray bursts is investigated. We discuss both the presence of a thermal continuum and, in particular, of collisional X-ray emission lines. We compute the predicted luminosity by a thin plasma for a range of metallicities for the continuum and the Kα lines of the elements Mg, Si, S, Ar, Ca and Fe. We show that light tra...

We consider the structure of steady–state radiative shock waves propagating in the partially ionized hydrogen gas with density ρ1 = 10 −10 gm cm and temperature 3000 K ≤ T1 ≤ 8000 K. The radiative shock wave models with electron thermal conduction in the vicinity of the viscous jump are compared with pure radiative models. The threshold shock wave velocity above of which effects of electron the...

The Biermann battery effect is frequently invoked in cosmic magnetogenesis and studied in high-energy density laboratory physics experiments. Generation of magnetic fields by the Biermann effect due to misaligned density and temperature gradients in smooth flow behind shocks is well known. We show that a Biermann-effect magnetic field is also generated within shocks. Direct implementation of th...

In the standard fireball model of gamma-ray bursts (GRBs), the fireball starts with an optically thick phase. As it expands, the fireball becomes optically thin at some stage. The thermal radiation trapped in the originally opaque fireball then leaks out, producing a transient event. The appearance of the event is investigated in the framework of a homogeneous, spherically symmetric, and freely...

The synthesis of supported palladium (Pd) catalysts is reviewed with emphasis on the chemistry of catalyst synthesis, oxidic and carbon support properties and case studies in the period 1990-2000. For the application of Pd onto oxidic supports aqueous precursor solutions are frequently used. The charge of the Pd precursor and the iso-electric point of the support are important properties since ...

The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and ...