On the EMP of High Altitude Nuclear Explosions

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Conventional Hall devices are widely employed to measure magnetic fields produced by millimetre sized (or larger) current-caring conductors or permanent magnets with a standard active area of about (100 um)^2. Micro-Hall sensors have recently emerged as a powerful and sensitive tool for the investigation of local magnetic field properties of the micro and nano-structures. The conventional Hall effect devices are based on non-magnetic materials (typically semiconductors e.g: AlGaAs/GaAs and InSb or semimetal

In this paper the effects of the magnetic self-field on the transport properties of a multi-layer high-Tc superconducting (HTS) cable are investigated by means of 2D finite element method (FEM) simulations. Analyzed is a 3-layer HTS cable, but the developed methods can be used for a different number of layers. The superconductor is described by the non-linear power-law relation E=Ec(J/Jc)^n, where the parameters Jc and n depend on the magnetic field experienced by the material. This dependence decreases the

We present an exact model for determining the cogging torque in a brushless DC (BLDC) motor. It is based on the conformal mapping (CM) method, by which the motor configuration is transformed to a configuration where the magnetic field can be determined. Then, by integrating the field over the stator surface, the cogging torque is determined. By varying some motor parameters, which is easy to do, an optimal configuration with the minimal cogging torque is obtained. We have confirmed the results by the finite

We study the dynamic motion of magnetic structures composed of micron-size ferromagnetic particles. The supraparticle structures are retained in a microfluidic channel by a local oscillating magnetic field while subjected to a viscous liquid flow. We analyze the position of the magnetic structures as a function of the flow velocity and of the frequency and amplitude of the magnetic field. We also study the conditions for release of the magnetic structures from the localized magnetic field region.

We have used electrically detected magnetic resonance (EDMR) to study the spin dependent processes on the operation of diodes based on poly(2-metoxy-5-(2'-etil-hexiloxy)-1,4-phenylene vinylene) (MEH-PPV) and on tris-8-hydroxyquinoline-aluminum (Alq3). In MEH-PPV based diodes, the EDMR signal is found to be composed of two lines, a Lorentzian with ΔHpp=5 G and a Gaussian with ΔHpp=24 G. The g-factor of both components is about 2.0022. The signal is quenching, typi

The present work is devoted to the study of the dynamics of multi-photon processes in semiconductor heterostructures. A time-dependent description is important for understanding in detail the transient response of semiconductors excited by ultrashort optical pulses. In the first part of this thesis, we set up a phenomenological model based on rate equations, in order to investigate the possibility of measuring degenerate two-photon gain in a semiconductor microcavity. The amplification predicted by the mode

Frequency doubling with a free-running long-pulse Nd:YAG laser and LBO or KTP nonlinear crystals yields conversion efficiency of up to 17.5% and 162 W peak power in the second harmonic. This efficiency is obtained for a TEM00 beam with rectangular temporal pulse shape of 50 to 400 s. To our knowledge, this is the highest second-harmonic generation (SHG) efficiency reported for the long-pulse free-running configuration. The efficiency is limited by optical damage with much lower threshold than in the Q-switc

The Karhunen-Loeve transform (KLT) is a key element of many signal processing tasks, including approximation, compression, and classification. Many recent applications involve {\em distributed} signal processing where it is not generally possible to apply the KLT to the signal; rather, the KLT must be approximated in a distributed fashion. This paper investigates such distributed approximations to the KLT. First, we present explicit solutions to special cases, including a partial KLT (where only a subset of

Basics of the theory of direct chaotic communications is presented. We introduce the notion of chaotic radio pulse and consider the signal structures and modulation methods applicable in direct chaotic schemes. Signal processing in noncoherent and coherent receivers is discussed. The efficiency of direct chaotic communications is investigated by means of numerical simulation. Potential application areas are analyzed, including multiple access systems.

This paper presents a chronological overview of the developments in interpolation theory, from the earliest times to the present date. It brings out the connections between the results obtained in different ages, thereby putting the techniques currently used in signal and image processing into historical perspective. A summary of the insights and recommendations that follow from relatively recent theoretical as well as experimental studies concludes the presentation.

In certain power applications, Bi-2223 conductors carrying AC current will be subjected to external magnetic fields, whose orientation and conductor’s geometry are of major significance for the AC loss magnitude. This paper investigates the influence of the geometry and aspect ratio of non-twisted Bi-2223 conductors in reducing the AC loss for such applications. A numerical model of high-Tc materials has been used in FEM simulations. The model incorporates power-law E-J characteristics with Jc defined by bo

Experimental data characterizing indoor electric and magnetic fields radiated by power line communication (PLC) systems and used for the calculation of a local transfer function (coupling factor) are presented. It is shown that the indirect determination of electric field using magnetic field measurements and assuming a plane wave approximation may result in an underestimation of the electric field. Additionally, it is shown that the radiated field magnitudes vary significantly as a function of the position

On the EMP of High Altitude Nuclear Explosions

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Bismuth Micro and Nano Hall Sensors on Photo-plastic Cantilevers for Scanning Hall Probe Microscopy

Numerical Analysis of the Effects of the Magnetic Self-Field on the Transport Properties of a Multilayer HTS Cable

Reducing the cogging torque in brushless DC motors by using conformal mappings

Dynamics of magnetically retained supraparticle structures in a liquid flow

Electrically detected magnetic resonance of organic and polymeric light emitting diodes

Dynamics of multi-photon processes in semiconductor heterostructures

High-power long-pulse second harmonic generation and optical damage with free-running Nd : YAG laser

The distributed Karhunen-Loeve transform

Introduction in direct chaotic communications

A Chronology of Interpolation: From Ancient Astronomy to Modern Signal and Image Processing

Geometry considerations for transport current applications of Bi-2223 conductors with anisotropic Jc(B) in external magnetic field

Indoor radiated emission associated with power line communication systems