Search results for " Design"

Relative principal congruences in congruence-modular quasivarieties

1998

The problem of definability of relative principal congruences in relatively congruence modular (RCM) quasivarieties is investigated. The RCM quasivarieties are characterized in terms of parameterized families of finite sets of pairs of terms which define relative principal congruences.

Ordinary and p-modular character degrees of solvable groups

1991

Solvable groups withp-modular character degrees of prime power

1990

Representations of Certain Banach C*-modules

2004

The possibility of extending the well known Gelfand–Naimark– Segal representation of *-algebras to certain Banach C*-modules is studied. For this aim the notion of modular biweight on a Banach C*-module is introduced. For the particular class of strict pre CQ*-algebras, two different types of representations are investigated.

Faithful representations of left C*-modules

2010

The existence of a faithful modular representation of a left module $$ \mathfrak{X} $$ over a C*-algebra $$ \mathfrak{A}_\# $$ possessing sufficiently many traces is proved.

Modular quintics inℙ4

2003

We will examine the arithmetic of some of the members of a pencil of symmetric quintics in projective 4-space. We will give evidence for the modularity of some of the exceptional members (even the non-rigid ones) and give a proof in one rigid case. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Waveguiding properties of a photonic crystal fiber with a solid core surrounded by four large air holes

2009

The polarization-dependent guiding properties of a hexagonal-lattice photonic crystal fiber with a solid-core surrounded by four large air holes are investigated. The appearance of a polarization dependent cutoff frequency, together with several parameters as the birefringence, the modal effective area, the group velocity dispersion and the polarization dependent loss are analyzed. A collection of fibers with different structural parameters were fabricated and characterized. An effective anti-guide structure from at least 450 nm to 1750 nm, a polarizing fiber with a polarization dependent loss of 16 dB/m at 1550 nm, and an endlessly singlemode polarization-maintaining fiber with group biref…

A Refractive Index Sensor Based on the Resonant Coupling to Cladding Modes in a Fiber Loop

2013

We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40-1.442, respectively, are demonstrated. We estimate a long range resolut…

Multioctave midinfrared supercontinuum generation in suspended-core chalcogenide fibers

2014

An As2S3 fiber-based supercontinuum source that covers 3500 nm, extending from near visible to the midinfrared, is successfully reported by using a 200-fs-pulsed pump with nJ-level energy at 2.5 μm. The main features of our fiber-based source are two-fold. On the one hand, a low-loss As2S3 microstructured optical fiber has been fabricated, with typical attenuation below 2 dB/m in the 1-4 μm wavelength range. On the other hand, a 20-mm-long microstructured fiber sample is sufficient to enable a spectral broadening, spreading from 0.6 to 4.1 μm in a 40 dB dynamic range.

Microstructured chalcogenide optical fibers from As2S3 glass: towards new IR broadband sources

2010

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