Electrical characteristics and reliability of UV transparent Si/sub 3/N/sub 4/ metal-insulator-metal (MIM) capacitors

In this paper, we discuss the electrical characteristics and reliability of UV transparent Si/sub 3/N/sub 4/ metal-insulator-metal (MIM) capacitors. We examine film thicknesses in the range of 55 to 25 nm with capacitance densities from 1.2 ff//spl mu/m/sup 2/ to 2.8 ff//spl mu/m/sup 2/, respectively, for single MIM capacitors. A new approach for projecting the dielectric reliability of these films extends the limits of maximum operating voltage. Accounting for temperature acceleration and area scaling, the projected lifetimes can be met for a wide range of operating conditions.     

Dispersion-tailored few-mode fibers: a versatile platform for in-fiber photonic devices

In-fiber devices enable a vast array of critical photonic functions ranging from signal conditioning (amplification, dispersion control) to network management (add/drop multiplexers, optical monitoring). These devices have become mainstays of fiber-optic communication systems because they provide the advantages of low loss, polarization insensitivity, high reliability, and compatibility with the transmission line. The majority of fiber devices reported to date are obtained by doping, designing, or writing gratings in the core of a single-mode fiber (SMF). Thus, these devices use the fiber only as a platform for propagating light-the device effect itself is due to some extraneously introduced material or structure (dopants for amplification, gratings for phase matching, etc.) There exists another, relatively less explored degree of freedom afforded by fibers-the ability to copropagate more than one mode. Each mode may have a uniquely defined modal dispersion and propagation characteristic. In this paper, we will describe the variety of fiber devices enabled by few-mode fibers-fibers that typically support two to four modes with suitably tailored dispersive properties. We will show that the unique dispersive properties of various modes, in conjunction with the ability to couple between them with gratings, leads to devices that offer novel solutions for dispersion compensation, spectral shaping, and polarization control, to name a few.     

Electrolytic recovery of zinc from zinc ash using a catalytic anode

The process of galvanisation of steel generates zinc ash as the waste product, thus creating pollution problems. The recovery of zinc metal from zinc ash, with a zinc content of about 76% by leaching and electrowinning has been studied. The presence of chloride has been identified as the major problem area. A catalytic anode based on iridium dioxide (IrO₂) was used as the anode material to overcome this problem. Catalyst loading was kept at an economically acceptable level. The catalyst's stability, energy consumption and efficiency of zinc recovery are discussed. The service life of the IrO₂ active coating has been established by an accelerated polarisation test. The zinc deposit recovered from the zinc ash has been examined by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Copyright © 2004 Society of Chemical Industry     

Multiple control input design for identification of light aircraft

This paper establishes a design technique for control input histories resulting in higher confidence levels in the estimate of lateral stability and control derivatives of light aircraft, and which cause dynamic motion favorable to reductions in numerical divergence tendencies in the identification algorithms. A combined aileron and rudder input design is demonstrated for the Cessna 172 aircraft.     

Austenite stabilization in stainless steel by hydrogen

It has been found that stabilization of austenite by hydrogen is governed not by its amount but by the manner of its introduction into the austenite just prior to transformation into martensite. In this case stabilization is to be understood as a decreasing tendency to transformation into martensite. The experimental results obtained using an appropriate material (steel No. 1.4576) show that cathodic impregnation brings about a stabilization of austenite as defined above.     

Evaluation of performance criteria of the CSI-IM drive system

The stability, sensitivity, and static velocity error coefficient of an induction motor (IM) drive fed by a current-source inverter (CSI) are analyzed to obtain the necessary information for the design of a practical system. These analyses are considered useful for determining an appropriate subsystem to compensate for performance deficiencies     

Thermal and optical properties of Cd1-x Zn x S thin films by photoacoustics

Ternary compounds Cd_1-x Zn _x S for various Zn concentration in thin films are synthesized by spray pyrolysis and studied by photoacoustics technique for thermal and optical properties. The thermal diffusivity as a function of the alloy composition measured by photoacoustics shows a maximum at x = 0.6. The optical band gap increases with zinc concentration and the continuous change indicates the formation of solid solution.