142,192 research outputs found
Conformational Control of Exciton-Polariton Physics in Metal - Poly(9,9-dioctylfluorene) - Metal Cavities
Control is exerted over the exciton-polariton physics in metal -
Poly(9,9-dioctyl fluorene) - metal microcavities via conformational changes to
the polymer backbone. Using thin-film samples containing increasing fractions
of -phase chain segments, a systematic study is reported for the mode
characteristics and resulting light emission properties of cavities containing
two distinct exciton sub-populations within the same semiconductor. Ultrastrong
coupling for disordered glassy-phase excitons is observed from angle-resolved
reflectivity measurements, with Rabi splitting energies in excess of 1.05 eV
(more than 30% of the exciton transition energy) for both TE- and TM-polarized
light. A splitting of the lower polariton branch is then induced via
introduction of -phase excitons and increases with their growing
fraction. In all cases, the photoluminescence emanates from the lowermost
polariton branch, allowing conformational control to be exerted over the
emission energy and its angular variation. Dispersion-free cavities with highly
saturated blue-violet emission are thus enabled. Experimental results are
discussed in terms of the full Hopfield Hamiltonian generalized to the case of
two exciton oscillators. The importance of taking account of the molecular
characteristics of the semiconductor for an accurate description of its strong
coupling behaviour is directly considered, in specific relation to the role of
the vibronic structure
Study of Multi-muon Events from EAS with the L3 Detector at Shallow Depth Underground
We present first preliminary data from the L3+Cosmics experiment and results
from Monte Carlo simulations of multi-muon events as observed 30 m underground.Comment: 3 pages, 2 figures; presented at the 6th International Workshop on
Topics in Astroparticle and Underground Physics, TAUP99, September 6-10,
1999, Paris, Franc
Structural Antennas for 3cm Radar Onboard Multi-Rotor UAV
A series of 3cm amateur band radar antennas suitable for installation on a cinematic grade multi-rotor UAV were considered. A wideband open waveguide mouth antenna was developed that can be made from the existing arms of a multi-rotor UAV without any increase in weight for side-looking wall detection ranging radar. For downward looking radio altimeter, cutting slots in the arms to form slotted waveguide antennas was shown in simulation to be possible both in terms of covering the entire 3cm band from 10 to 10.5GHz and without overly weakening the arms as structural members
Expressive Stream Reasoning with Laser
An increasing number of use cases require a timely extraction of non-trivial
knowledge from semantically annotated data streams, especially on the Web and
for the Internet of Things (IoT). Often, this extraction requires expressive
reasoning, which is challenging to compute on large streams. We propose Laser,
a new reasoner that supports a pragmatic, non-trivial fragment of the logic
LARS which extends Answer Set Programming (ASP) for streams. At its core, Laser
implements a novel evaluation procedure which annotates formulae to avoid the
re-computation of duplicates at multiple time points. This procedure, combined
with a judicious implementation of the LARS operators, is responsible for
significantly better runtimes than the ones of other state-of-the-art systems
like C-SPARQL and CQELS, or an implementation of LARS which runs on the ASP
solver Clingo. This enables the application of expressive logic-based reasoning
to large streams and opens the door to a wider range of stream reasoning use
cases.Comment: 19 pages, 5 figures. Extended version of accepted paper at ISWC 201
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A Case of Hyperkalemia Versus Pseudohyperkalemia in Chronic Lymphocytic Leukemia
Introduction: Both hyperkalemia and pseudohyperkalemia occur in the emergency department. True hyperkalemia necessitates emergent treatment while pseudohyperkalemia requires recognition to prevent inappropriate treatment. It is imperative that the emergency physician (EP) have an understanding of the causes and clinical presentations of both phenomena.Case Report: We present a case of an 88-year-old male with chronic lymphocytic leukemia (CLL) and suspected blast crisis who was found to have elevated serum potassium levels without other manifestations of hyperkalemia and eventually was determined to have pseudohyperkalemia due to white cell fragility.Discussion: Differentiation of hyperkalemia and pseudohyperkalemia is a critical skill for the EP. We discuss multiple causes of hyperkalemia and pseudohyperkalemia in an effort to broaden the knowledge base.Conclusion: We present a case of CLL as an unusual cause of pseudohyperkalemia and review common causes of pseudohyperkalemia
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