Gamma-Rays from Large Scale Structure Formation and the Warm-Hot Intergalactic Medium: Cosmic Baryometry with Gamma-Rays

It is shown that inverse Compton gamma-rays from electrons accelerated in large scale structure formation shocks can be crucially affected by non-gravitational effects such as radiative cooling and galaxy formation, with corresponding uncertainties by an order of magnitude in either the gamma-ray source counts or the extragalactic background contribution. However, this also implies that such gamma-rays may in the near future provide us with valuable information about the fraction of cosmic baryons in different forms, particularly the warm-hot intergalactic medium where the majority of the baryons in the universe are believed to reside. We address this problem in a simple way through semi-analytic modeling of structure formation shocks which self-consistently treats merger and accretion shocks.Comment: 7 pages, 2 figures; slightly modified version of article to appear in Proc. of the "International Symposium on High Energy Gamma-Ray Astronomy" Heidelberg (2004), eds. F.A. Aharonian, H.J. Voelk and D. Horns (AIP, NY

Resonant-wavelength control of nanocavities by nanometer-scaled adjustment of two-dimensional photonic crystal slab structures

In this letter, we experimentally demonstrate resonant-wavelength control of a series of 16 nanocavities in a two-dimensional photonic crystal slab structure by nanometer-order variation of the lattice constants and air-holes sizes. The cavities show a linear dependence on these parameters, a 1-nm increase of lattice constant or air-hole size leading to 4.2-nm increase or 1.56-nm decrease of the resonant wavelength, respectively. These experimental results are in good agreement with the finite-difference time-domain calculations and have a small standard deviation of wavelength (~1 nm) between samples on a single chip. These results will stimulate development in areas such as ultrasmall and multichannel filters, sensors, and switches

Measurement of Wireless LAN Characteristics in Sewer Pipes for Sewer Inspection Systems Using Drifting Wireless Sensor Nodes

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Resonant-wavelength control of nanocavities by nanometer-scaled adjustment of two-dimensional photonic crystal slab structures

In this letter, we experimentally demonstrate resonant-wavelength control of a series of 16 nanocavities in a two-dimensional photonic crystal slab structure by nanometer-order variation of the lattice constants and air-holes sizes. The cavities show a linear dependence on these parameters, a 1-nm increase of lattice constant or air-hole size leading to 4.2-nm increase or 1.56-nm decrease of the resonant wavelength, respectively. These experimental results are in good agreement with the finite-difference time-domain calculations and have a small standard deviation of wavelength (~1 nm) between samples on a single chip. These results will stimulate development in areas such as ultrasmall and multichannel filters, sensors, and switches