Search results for "Toe"
showing 10 items of 3824 documents
Coexistence of quasi-CW and SBS-boosted selfQ-switched pulsing in ytterbium-doped fiber laser with low Q-factor cavity
2020
We report the results of an experimental study of an ytterbium-doped fiber laser with low Q-factor cavity. We demonstrate that the laser operates in two randomly alternating sub-regimes, quasi-CW (QCW) and self-Q-switching (SQS), the latter ignited by stimulated Brillouin scattering (SBS). We show that probability of each sub-regime depends on pump power: QCW dominates slightly above the laser threshold while SQS pulsing prevails at higher pump powers. We also discuss the featuring details of QCW sub-regime and its role in instabilities (jittering) of SBS-boosted SQS pulsing as well as the statistical properties of the latter.
<title>Advanced light sources for atomic absorption analysis</title>
2003
High-frequency electrodeless light sources (HF EDLS) are widely used as bright radiators of narrow and intensive atomic and ionic spectral lines, covering the spectrum from VUV to IR. Main characteristics of HF EDLS are high emitted spectral line intensity, long service life, and in general, narrow spectral line shapes because of low-pressure of filling elements. In this work we give a short overview of the use of HF EDLS, containing Hg, Te, Se, Zn, Pb, As, Sb, Bi, Tl, In, Cd, Sn, in Zeeman Atomic absorption devices for assaying natural, drinking, waste and technical water as well as air, soil, food products and biological samples. The first steps are made for optimization of Ge, Ga, P, S, …
Spectroscopic response and charge transport properties of CdZnTe detectors grown by the vertical Bridgman technique
2015
In this work, we present the results of spectroscopic investigations on CdZnTe (CZT) detectors grown by the boron oxide encapsulated vertical Bridgman technique (1MEM-CNR, Parma, Italy). The detectors, with different thicknesses (1 and 2.5 mm), are characterized by the same electrode layout (gold electroless contacts): the anode is a central electrode (2 x 2 mm(2)) surrounded by a guard-ring electrode, while the cathode is a planar electrode covering the detector surface (4.1 x 4.1 mm(2)). The results of electrical investigations point out the low leakage currents of these detectors even at high bias voltages: 38 nA/cm(2) (T = 25 degrees C) at 10000 V/cm. The time stability and the spectros…
Study on the initial stages of water corrosion of fluorozirconate glasses
2004
Abstract The surface corrosion process associated with the hydrolysis of fluorozirconate glass, ZBLAN (53ZrF 4 , 20BaF 2 , 20NaF, 4LaF 2 , 3AlF 3 ) was investigated using X-ray photoelectron spectroscopy (XPS), grazing-incidence small angle X-ray scattering (GISAXS), X-ray reflectivity (XRR) and scanning electron microscopy (SEM). After a short exposure period (25 min) of the glass surface to deionized water the XPS data indicate an increase of the oxygen content accompanied by a decrease of fluorine concentration. The analysis of the chemical bonding structure identified the predominant surface reaction products as zirconium hydroxyfluoride and oxyfluoride species. The second most abundant…
Chemical Bath Deposition as a Simple Way to Grow Isolated and Coalesced ZnO Nanorods for Light-Emitting Diodes Fabrication
2018
A way to grow and characterize isolated and coalesced ZnO nanorods on $p$ -GaN/sapphire structure is presented. Chemical bath deposition can be used to grow ZnO nanorods of device-quality, simply controlling the duration time of the growth process and the concentration of the nutrient solution in the bath. Increasing the duration of the process, as well as the concentration of the solution, leads to compact and sound layers instead of separated nanorods. However, too high concentrations stop the growth process. Light-emitting diodes fabricated on these ZnO-p-GaN heterostructure have a peak of electroluminescence at 400 nm and exhibit interesting electrical and optical properties. Optical po…
Dietary exposure in utero and during lactation to a mixture of genistein and an anti-androgen fungicide in a rat mammary carcinogenesis model
2015
Endocrine disruptors may play substantial roles in the high incidence of breast cancer. We previously described how early exposure to the mixture of phytoestrogen genistein (G) and the anti-androgen vinclozolin (V) affects peripubertal mammary development. This study evaluates the carcinogenic potential of exposure to V alone or associated with G from conception until weaning in Wistar rats. Dams were exposed to V, G or GV during pregnancy/lactation. At PND50 offspring were treated with DMBA[7,12-dimethylbenz(a)anthracene]. V or GV maternal exposure decreased number of DMBA-induced mammary tumors in the offspring, without significant modifications in tumor incidence, multiplicity and latenc…
Acyl-homoserine lactone production is more common among plant-associated Pseudomonas spp. than among soilborne Pseudomonas spp.
2001
ABSTRACT A total of 137 soilborne and plant-associated bacterial strains belonging to different Pseudomonas species were tested for their ability to synthesize N -acyl-homoserine lactones (NAHL). Fifty-four strains synthesized NAHL. Interestingly, NAHL production appears to be more common among plant-associated than among soilborne Pseudomonas spp. Indeed, 40% of the analyzed Pseudomonas syringae strains produced NAHL which were identified most often as the short-chain NAHL, N -hexanoyl- l -homoserine lactone, N -(3-oxo-hexanoyl)-homoserine lactone, and N -(3-oxo-octanoyl)- l -homoserine lactone (no absolute correlation between genomospecies of P. syringae and their ability to produce NAHL …
Terpyridine-based metallopolymer thin films as active layer in ammonia sensor device
2016
International audience; A metal-containing polymer has been prepared by electropolymerization of an homoleptic Ru(II)-terpyridine complex bearing pyrrole heterocycles. The polymer is obtained as a thinfilm at the surface ofelectrodes, and has been characterized by electrochemical measurements, XPS and microscopy. It hasbeen shown that this polymer acts as an active gas sensitive layer since it enables the detection of anammonia gasflow through layer’s resistivity measurements.
All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity
2006
International audience; A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (211) regeneration at 160 Gbits/s.
Near-field spectroscopy of low-loss waveguide integrated microcavities
2006
International audience; A scanning near-field spectroscopy method is used to observe loss reduction and Q-factor enhancement due to transverse-mode profile matching within photonic-crystal microcavities. Near-field measurements performed directly on cavity modes are compared with three-dimensional calculations and quantitative agreement is observed. (c) 2006 American Institute of Physics.