Search results for "ESA"

Segregation of lipid in Ir-dye/DMPA mixed monolayers as strategy to fabricate 2D supramolecular nanostructures at the air–water interface

2008

A novel pseudospherical fluorinated iridium(III) derivative, Ir-dye/PF6, [Ir(F2-ppy)2(bpy)]PF6 (F2-ppy = 2-(2,4-difluoro)phenylpyridine, bpy = 2,2′-bipyridine), has been organized by using a lipid matrix, DMPA (dimyristoyl-phosphatidic acid), in several molar ratios at the air–water interface. The molecular organization of both components and the degree of miscibility in the different mixed films have been inferred by surface techniques such as π–A isotherms, ellipsometry, reflection spectroscopy, Brewster angle microscopy (BAM), and IR spectroscopy for the LB films, additionally the results have been discussed according to the additivity rule. The equimolecular Ir-dye/DMPA mixture leads to…

PLZT Electro-optic Q-switch for Er:Cr:YSGG laser

1999

Q-switching of the Er:Cr:YSGG laser at 2.79 micrometers is realized using electrooptic modulators of PLZT X/65/35 ceramics. The high (but slow as compared with single crystals) electrooptical effect in PLZT allowed to construct Q-switches with an aperture larger than 4 X 4 mm 2 , small lengths of 3 - 6 mm, with a control voltage of 1000 - 1500 V. Q-switching is realized using modulators in two modes--as a (lambda) /2 switch placed into the laser cavity at the Brewster angle avoiding reflection losses and as a (lambda) /4 switch with higher single pass losses due to Fresnel reflections. A higher laser output was obtained using (lambda) /2 switching. The obtained pulses had a halfwidth of 150…

A Simple Apparatus for the Determination of the Optical Constants and the Thickness of Absorbing Thin Films

2001

We report on a simple and inexpensive apparatus useful for measuring the optical constants n, k and the thickness of weakly absorbing thin films. The measurement is based on an accurate determination of the reflectance and transmittance of a specimen illuminated by a laser beam. The laser beam is incident on a transparent substrate coated with the film to be evaluated, with an angle of incidence equal to the Brewster angle for the substrate, and its polarization can be switched between the p and s states. If the thickness is known to be within a presumptive range, measurements of the p and s reflectance and transmittance allow a calculation of the optical constants n, k and the thickness of…

Improvement of solid state Er:YAG pulse laser performance for use in medicine

1999

The large quadratic electro-optic effect of PLZT ceramics allows to design small size modulators for the solid state infrared Er:YAG laser (lasing at (lambda) equals 2.94 micrometers - the most pronounced absorption band of water), which has found application in medicine for efficient ablation of hard and soft tissues. In the free-running mode, the Er:YAG laser emits spikes that form the pulse envelope with duration of 150 - 800 microsecond(s) . An extracavity PLZT 8.5/65/35 ceramics modulator (aperture of 4 X 6 mm2 and length of 18 mm) was used to obtain (Pi) -shaped segments with the rise and decay times less than 5 microsecond(s) . That allows to reduce considerably the fraction of the p…

Relativistic beaming and gamma-ray brightness of blazars

2009

We investigate the dependence of gamma-ray brightness of blazars on intrinsic properties of their parsec-scale radio jets and the implication for relativistic beaming. By combining apparent jet speeds derived from high-resolution VLBA images from the MOJAVE program with millimetre-wavelength flux density monitoring data from Metsahovi Radio Observatory, we estimate the jet Doppler factors, Lorentz factors, and viewing angles for a sample of 62 blazars. We study the trends in these quantities between the sources which were detected in gamma-rays by the Fermi Large Area Telescope (LAT) during its first three months of science operations and those which were not detected. The LAT-detected blaz…

Electronic and Functional Scope of Boronic Acid Derived Salicylidenehydrazone (BASHY) Complexes as Fluorescent Dyes

2017

[EN] A series of boronic acid derived salicylidenehydrazone (BASHY) complexes was prepared and photophysically characterized. The dye platform can be modified by (a) electronic tuning along the cyanine-type axis via modification of the donor-acceptor pair and (b) functional tuning via the boronic acid residue. On the one hand, approach (a) allows the control of photophysical parameters such as Stokes shift, emission color, and two-photon absorption (2PA) cross section. The resulting dyes show emission light-up behavior in nonpolar media and are characterized by high fluorescence quantum yields (ca. 0.5-0.7) and brightness (ca. 35000-40000 M-1 cm(-1)). Moreover, the 2PA cross sections reach …

Briseles I-bis regulas risinājumi un nepilnības

2017

Šajā maģistra darbs pētītas izmaiņas Briseles I regulā, kuras savā Priekšlikumā Briseles I regulas reformai izvirzīja Eiropas Komisija. Šis Priekšlikums rezultējās tagadējā Briseles I-bis regulā. Pētījuma mērķis ir noskaidrot, vai galvenās četras no Priekšlikumā minētajām problēmām ir atrisināts, un vai to vietā nav nākušas kādas citas. Pētījuma rezultātā secināts, ka ekzekvatūras atcelšana bijusi lielākoties veiksmīga, vienošanos par jurisdikciju efektivitāti ir palielināta, kā arī daļēji īstenots mērķis apturēt paralēlas tiesvedības un torpedēšanas tiesvedības attiecībā uz šķīrējtiesām.

Detecting faulty wireless sensor nodes through Stochastic classification

2011

In many distributed systems, the possibility to adapt the behavior of the involved resources in response to unforeseen failures is an important requirement in order to significantly reduce the costs of management. Autonomous detection of faulty entities, however, is often a challenging task, especially when no direct human intervention is possible, as is the case for many scenarios involving Wireless Sensor Networks (WSNs), which usually operate in inaccessible and hostile environments. This paper presents an unsupervised approach for identifying faulty sensor nodes within a WSN. The proposed algorithm uses a probabilistic approach based on Markov Random Fields, requiring exclusively an ana…

MR2876776 Orhan, C.; Tas, E.; Yurdakadim, T. The Buck-Pollard property for $p$-Cesàro matrices. Numer. Funct. Anal. Optim. 33 (2012), no. 2, 190--196.

2012

Two mesalazine regimens in the prevention of the post-operative recurrence of Crohn's disease: a pragmatic, double-blind, randomized controlled trial

2003

Summary Background : The role of mesalazine in preventing the clinical recurrence of Crohn's disease after surgery has been shown in a meta-analysis of all published studies. No clear relationship, however, has been shown between dosage and response. Aim : To evaluate whether 4.0 g/day of mesalazine may offer therapeutic advantages over 2.4 g/day in the prevention of both endoscopic and clinical post-operative recurrence of Crohn's disease. Methods : The study was a double-blind, randomized, multi-centre, prospective, controlled clinical trial. Two hundred and six patients, submitted to first or second intestinal resection for Crohn's disease limited to the terminal ileum, with or without i…