A fundamental requirement in the new generation of high resolution Cosmic Microwave Background imaging experiments is a strict control of systematic errors that must be kept at μK level in the final maps. Some of these errors are of celestial origin, while others will be generated by periodic fluctuations of the satellite environment. These environment instabilities will cause fluctuations in t...

Turbulent Comptonization, a potentially important damping and radiation mechanism in relativistic accretion flows, is discussed. Particular emphasis is placed on the physical basis, relative importance, and thermodynamics of turbulent Comptonization. The effects of metal-absorption opacity on the spectral component resulting from turbulent Comptonization is considered as well. 1. Overview of Th...

The radiation fields of a line source enclosed in a circular dielectric radome with grating consisting of an array of thin lossy metal strips are analyzed. The variations of the directivity of the source beam with respect to the beam direction are studied. The possibility of damping these variations by an appropriate design of the radome is demonstrated.

Malaysians were reported to have the most number of Facebook friends, spend more time on Facebook and might be addicted to Facebook as well. This paper explored Facebook usage pattern, motivations and psycho logical/behavioural factors affecting the users. A focus group study was first conducted to explo re motives to use Facebook and symptoms related to excessive Facebook usage. The themes eme...

INTRODUCTION The SNR efficiency in MR experiments is intrinsically limited by longitudinal-, and transverse spin relaxation mechanisms. This becomes particularly limiting for unbalanced, short repetition time (TR) sequences, where incomplete T1-relaxation results in a steady-state signal that is only a small fraction of the available thermal equilibrium magnetization. Radiation damping (RD) is ...

The generation of small emittance beams is a key issue determining the luminosity at a future linear collider. Dedicated damping rings have been designed to produce such beams, but techniques to further reduce the design emittances would yield immediate improvements in terms of higher luminosity. At injection into the damping rings, the transverse beam emittances are large and the beam fills a ...

We use ultrafast THz spectroscopy to study Landau damping in a coherent plasma system. A series of InSb-based bulk heterostructures provide increasing spatial confinement that restricts the scattering wave vector in the electron-electron interaction. This results in a dramatic reduction of the plasma contribution to the radiation signal. The experimental results are explained by model calculati...

We analyze a phenomenon of near-resonance in an oscillator with small damping and make connections to blackbody radiation and the acoustics of string instruments. We find that near-resonance with small damping is characterized by an efficiency index E ≈ 1 as the quotient of the damping energy and the forcing energy, as a result of a phase shift of a quarter of a period beween forcing and veloci...

The nonlinear system of equations of relativistic Lorentz electrodynamics (LED) is studied in a “gyroscopic setup” in which the Lorentz electron is assumed to remain at rest, leaving the electromagnetic fields and the particle spin as the only dynamical degrees of freedom. The global existence and uniqueness of this gyroscopic spin-plus-field dynamics in unbounded space is proven. It is further...