Search results for "DT"

Gain lifetime measurement of a Ni-like Ag soft X-ray laser

2012

International audience; Experimental results of a two-stage Ni-like Ag soft X-ray laser operated in a seed-amplifier configuration are presented. Both targets were pumped applying the double-pulse grazing incidence technique with intrinsic travelling wave excitation. The injection of the seed X-ray laser into the amplifier target was realized by a spherical mirror. The results show amplification of the seed X-ray laser and allow for a direct measurement of the gain lifetime. The experimental configuration is suitable for providing valuable input for computational simulations. (C) 2012 Optical Society of America

Control of signal coherence in parametric frequency mixing with incoherent pumps: Narrowband mid-infrared light generation by downconversion of broad…

2012

International audience; We study, with numerical simulations using the generalized nonlinear envelope equation, the processes of optical parametric and difference- and sum-frequency generation (SFG) with incoherent pumps in optical media with both quadratic and third-order nonlinearity, such as periodically poled lithium niobate. With ultrabroadband amplified spontaneous emission pumps or continua (spectral widths > 10 THz), group-velocity matching of a near-IR pump and a short-wavelength mid-IR (MIR) idler in optical parametric generation may lead to more than 15-fold relative spectral narrowing of the generated MIR signal. Moreover, the SFG process may also lead to 6-fold signal coherence…

Algebraic real-time algorithm for B-Spline sinusoidal pulse width modulation in three phase voltage source inverters.

2008

In this paper a novel algebraic real-time algorithm for implementation of sinusoidal pulse width modulation (SPWM) based on B-spline carriers is introduced and discussed. B-spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. This algorithm eliminates the problem of B-spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way the carrier signals have not to be really synthesized, hence the hardware and the whole inverter control system becomes cheaper, more reliable and affo…

Computationally efficient dynamical analysis of optically driven injection-locked GaAs FET oscillators

1995

A computer-aided simulation technique for the dynamical analysis of a class of GaAs FET optically-driven injection-locked oscillators (ODILO's) is presented. By combining a measurement-derived nonlinear model of the illuminated transistor with a phasor-domain analysis method, a first-approximation - but phenomenologically complete - differential model of the synchronized oscillator is derived. Since amplitude and phase of waveform evolutions are directly addressed and evaluated in a stroboscopic-time scale, the calculation of the transient response to modulated input signals can be done in a more user-friendly and computationally efficient manner than possible through conventional time-doma…

Architecture of a digital PFM controller for IC implementation

2006

This paper presents a digital controller architecture oriented to IC implementation. The classical digital pulse width modulator (D-PWM), using digital analog converter (DAC), is replaced with a Sigma-Delta (/spl Sigma//spl Delta/) modulator based on pulse frequency modulator (PFM) technique. Results of an investigation from a prototype for DC-DC converter, in terms of simulated and experimental performances, are reported, together with harmonic frequency investigation. The control function design is implemented on a field programmable gate array (FPGA). As a consequence of good agreement between simulated and experimental results, the proposed architecture realizes a digital control loop w…

Some aspects of the recovery of chlorinated residues (DDT-type compounds and PCB) from fish tissue by using different extraction methods

1974

Ready Access to Proquinazid Haptens via Cross-Coupling Chemistry for Antibody Generation and Immunoassay Development.

2015

17 pages, 4 tables, 5 figures.-- Publisher's PDF

Determination of the crystallinity of TiO2 photocatalysts

2018

Abstract This study reports a new simple method to determine the crystallinity of anatase and rutile TiO2 photocatalysts. The crystallinity degree of various anatase and rutile samples was estimated by XRD analysis from the ratio among the full width at half maximum intensities of the main diffraction peaks of anatase or rutile and the (111) peak of CaF2 as internal standard. The photocatalytic activity of selected powders was tested employing the photodegradation of 4-nitrophenol in aqueous solution as probe reaction. The results showed that the photoactivity of the investigated samples increased with increasing crystallinity and crystallite size.

Study of the structural changes induced by air oxidation in Ti–Si–N hard coatings.

2008

International audience; 3-μm thick Ti–Si–N coatings were deposited on polished X38CrMoV5 substrates by sputtering a composite Ti–Si target in Ar–N2 reactive mixture. Oxidation tests were performed in air at 700 °C during 2 h. Whatever the silicon content in the range 0–4 at.%, no silicon containing compound was detected by XRD before air oxidation and only the TiN phase was evidenced. The mean grain size estimated from the full width at half maximum of the TiN (111) diffraction peak was close to 10 nm. As commonly reported for Ti–Si–N films, the hardness showed a maximum at 51 GPa versus the Si content. After oxidation of the TiN film, XRD and micro-Raman analyses revealed the occurrence of…

Mūzikas ierakstu grafa vizualizācija un atskaņošana Android viedtālruņos

2019

Bakalaura darbā tiek apskatīta un risināta grafu rediģēšanas problēma uz mazu izmēru skārienjūtīgajām ierīcēm. Darba mērķi ir sekojoši: analizēt un salīdzināt esošos grafu rediģēšanas risinājumus uz dažādām platformām(Windows, Android un Web) un, ņemot vērā analizēto informāciju, izveidot Android lietotni, kas ļauj veidot, rediģēt un vizualizēt grafus, kā arī realizēt lietotnē izveidotā grafu rediģēšanas iespēju citās programmās, izmantojot populārāko grafu failu formātu. Darba ietvaros tika secināts, ka esošie risinājumi nenodrošina grafu rediģēšanu pietiekami ērtā veidā uz maza izmēra skārienjūtīgām ierīcēm. Darba autors šo problēmu mēģināja risināt, izmantojot automātisku virsotņu un šķa…