Search results for " Spontaneou"

Experimental demonstration of 160-GHz densely dispersion-managed soliton transmission in a single channel over 896 km of commercial fibers

2003

International audience; We experimentally demonstrate the first 160-GHz densely dispersion-managed soliton transmission in a single channel at 1550 nm over nearly 900 km using commercially available non-zero dispersion-shifted fibers. This performance has been achieved by using a 16 km-long recirculating loop configuration and an appropriate design of the dispersion map.

Flaticon pulses in optical fibers

2014

International audience; We experimentally investigate the nonlinear reshaping of a continuous wave which leads to chirp-free and flat-top intense pulses or flaticons exhibiting strong temporal oscillations at their edges and a stable self-similar expansion upon propagation of their central region.

All optical solition-based 2R regeneration at 170 Gbps

2010

[NMB4]; International audience; We report the numerical and experimental studies of a spectrally filtered-based all-optical 2R regenerator at 170 Gbps. The fiber device is combined with a fast saturable absorber. BER assessment exhibits a receiver sensitivity improvement.

Piranilidena atvasinājumu optiskās un pastiprinātas spontānās emisijas īpašības PVK matricā

2015

Organiskie materiāli ir daudzsološi dažādiem moderniem pielietojumiem, tai skaitā optiski ierosinātiem organiskajiem cietvielu lāzeriem, kuriem vajadzīgi materiāli ar augstu pastiprināšanās koeficientu un zemām ierosmes enerģijām. Vairumā organisko sistēmu šie parametri ir limitēti krāsvielu molekulu kristalizācijas dēļ. Tādēļ savienojumi ar samazinātu kristalizēšanos būtu ļoti noderīgi. Šajā darbā tika pētītas plānās kārtiņas ar jauniem plaši zināmās krāsvielas DCM atvasinājumiem PVK polimēra matricā dažādās koncentrācijās. Kārtiņām tika uzņemti fotoluminiscences spektri un veikti pastiprinātas spontānās emisijas (PSE) mērījumi. Tika novērota spēcīga koncentrācijas ietekme uz emisijas spek…

Spontaneous Regression of a Recalcitrant Wart after Bivalent Papillomavirus Vaccination

2017

Ventilation/perfusion ratios measured by multiple inert gas elimination during experimental cardiopulmonary resuscitation

2014

Background During cardiopulmonary resuscitation (CPR) the ventilation/perfusion distribution (VA/Q) within the lung is difficult to assess. This experimental study examines the capability of multiple inert gas elimination (MIGET) to determine VA/Q under CPR conditions in a pig model. Methods Twenty-one anaesthetised pigs were randomised to three fractions of inspired oxygen (1.0, 0.7 or 0.21). VA/Q by micropore membrane inlet mass spectrometry-derived MIGET was determined at baseline and during CPR following induction of ventricular fibrillation. Haemodynamics, blood gases, ventilation distribution by electrical impedance tomography and return of spontaneous circulation were assessed. Inter…

Headache in cerebrospinal fluid volume depletion syndrome: A case report

2006

Cerebrospinal fluid (CSF) volume depletion syndrome is due to leakage of cerebrospinal fluid through lesions of the dural sac at the level of the cranial base or of the spine. When past medical history is negative for recent trauma or surgery, the term spontaneous intracranial hypotension (SIH) is used. SIH is characterized clinically by orthostatic headache, neck pain, nausea, emesis, horizontal diplopia, tinnitus, plugged ear, hearing difficulties, blurring of vision, facial numbness, and upper limb radicular symptoms. In SIH, brain and cervical MR scans show a diffuse pachymeningeal gadolinium enhancement that ends at the site of CSF leakage. The application of epidural blood patches has…

HAPPY Dyes as Light Amplification Media in Thin Films

2021

A series of 1Hamorphous tri-phenyl pyridine (HAPPY) dyes have been synthesized from luminescent triphenyl-group-containing 2-methyl-6-styryl-substituted-4H-pyran-4-ylidene derivatives in reactions with benzylamine and investigated for suitability as solution-processable light-emitting medium components in thin films for amplified spontaneous emission (ASE). Conversion of a 4H-pyrane ring into a 1H-pyridine fragment enables aggregation-induced emission enhancement (AIEE) behavior in the target products and slightly increases thermal stability, glass transition temperatures, and ASE efficiency with PLQY up to 15% and ASE thresholds as low as 46 μJ/cm2 in neat spin-cast films, although thermal…

Glass-forming non-symmetric bis-styryl-DWK-type dyes for infra-red radiation amplification systems

2019

Abstract A series of D-π-A type organic dyes with bulky triphenylmethyl moiety containing 2,6-bis-(4-substituted)styryl-4H-pyran-4-ylidene donor (D) fragments and different electron acceptors (A) were synthesized and investigated, mostly for potential applications in organic solid-state lasers as infra-red (IR) radiation amplification medium. Dye glass transition temperature is above 99 °C with thermal stability in the region from 173 °C to 326 °C which was slightly influenced by the electron acceptor fragment attached to the 4H-pyrane ring in 4-position. Introducing substituents in 4-position within one of the styryl-fragments with stronger electron withdrawing properties decreased ASE exc…

Fluorescence and amplified spontaneous emission of glass forming compounds containing styryl-4H-pyran-4-ylidene fragment

2012

Potential of glassy films of newly synthesised low molecular weight organic molecules for light amplification and lasing applications has been investigated by analysing fluorescence, transient differential absorption and amplified spontaneous emission properties. These non-symmetric and symmetric molecules contain styryl-4H-pyran-4-ylidene fragment with three different electron acceptor groups: dicyanomethylene, barbituric acid, indene-1,3-dione. Fluorescence quantum yields of the investigated compounds in solutions are between 0.32 and 0.54, while they drop down by an order of magnitude in thin solid films. Incorporation of bulky side groups reduced excitonic interactions enabling manifest…