THE DYNAMIC BEHAVIOR AND THE STRUCTURE OF THE MAGNETIZATION IN RE-ENTRANT SPIN-GLASSES

Lorentz electron transmission microscopy observations of the domains-structure in amorphous Fe1-xZrx (x = 9 to 13 % ) films (1000 to 2000 Å thick) near liquid helium temperature are reported. Several levels of magnetic fluctuations with a large distribution of wave lengths ranging from several tens of µm to few hundreds angstroms are seen

AES, XPS AND TEM CHARACTERIZATION OF BORON NITRIDE DEPOSITED UNDER CHEMICAL VAPOR INFILTRATION (CVI) CONDITIONS

Des dépôts de nitrure de bore, élaborés à partir de mélanges gazeux BF3-NH3 dans des conditions CVI et déposés dans des préformes fibreuses ou sur des substrats plans de carbure de silicium ont été caractérisés par XRD, AES, XPS et TEM. Ces dépôts sont non stoechiométriques et possèdent du bore en excès (N:B at = 0,6 - 0,8) ainsi qu'une quantité non négligeable d'oxygène. L'unité structurale de base se compose d'hexagones quasi parfaits. L'arrangement des couches est typiquement turbostratique (d002 = 3,64 Å ; Lc = 28 Å). Ces empilements sont aléatoirement orientés au sein du dépôt mais tendent à s'orienter parallèlement à l'interface proche du substrat. Le dépôt comporte des pores submicroscopiques, une faible densité (1,6 - 1,9 g.cm-3) et une certaine nanoporosité (8 - 22 %). La microstructure est semblable à celle du pyro-carbone élaboré dans des conditions similaires.BN-films deposited, from BF3-NH3 mixtures under CVI-conditions, either within porous SiC fiber preforms or on plan sintered SiC substrates, have been characterized, at a submicron scale, by XRD, AES, XPS and TEM. The deposits are non-stoichiometric with an excess of boron (N:B at. = 0.6 - 0.8) and contain a significant amount of oxygen. The basic structural unit is an almost perfect hexagonal ring. The stacking of the hexagonal layers is turbostratic (d002 = 3.64 Å ; Lc = 28 Å). The BN layers are randomly orientated in the bulk of the deposit but tend to be aligned parallel to the interface near the substrate surface. The deposit contains numerous submicroscopic pores. It has a low density (1.6 - 1.9 g.cm-3) and a significant nanoporosity (8 - 22 %). The main features of the microstructure are similar to those of pyrocarbon deposits

Modelling and Improving Flow Establishment in RSVP

RSVP has developed as a key component for the evolving Internet, and in particular for the Integrated Services Architecture. Therefore, RSVP performance is crucially important; yet this has been little studied up till now. In this paper, we target one of the most important aspects of RSVP: its ability to establish flows. We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism. Then, we propose a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP. We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances