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In general, a system can be defined as a collection of interconnected components that transforms a set of inputs received from its environment to a set of outputs. From an engineering point of view, chaos-based applications can be classified as a electronic system where the vast majority of the internal signals used as interconnections are electrical signals. Inputs and outputs are also provided as electrical quantities, or converted from, or to, such signals using sensors or actuators. To gain insight about the overall performance of the particular chaos-based application, the whole system must be characterized and simulated simultaneously. That is not a trivial task because the complexity of each one of the blocks that comprises the system, as well as the intrinsic complex behavior of chaotic generators. In this chapter, a modeling strategy suited to represent chaos-based applications for different control parameters of chaotic systems is presented. Based on behavioral descriptions obtained from a Hardware Description Language (HDL), called Verilog-A, two applications of chaotic systems are analyzed and designed. More specifically, a chaotic sinusoidal pulse width modulator (SPWM) which is useful to develop control algorithms for motor drivers in electric vehicles, and a chaotic pulse position modulator (CPPM) widely used in communication systems are presented as cases under analysis. Those applications are coded in Verilog-A and by using different abstraction levels, the indications of the degree of detail specified on how the function is to be implemented are obtained. Therefore, these behavioral models try to capture as much circuit functionality as possible with far less implementation details than the device-level description of the electronic circuit. Several circuit simulations applying H-Spice simulator are presented to demonstrate the usefulness of the proposed models. In this manner, behavioral modeling can be a possible solution for the successful development of robust chaos-based applications due to various types of systems that can be represented and simulated by means of an abstract model.

This work reports an extensive collection of 120 atomic transition probabilities of Kr II lines in the spectral region 350–720 nm, all of them measured in an emission experiment. For many of them, these are the first data up to the authors' knowledge. Relative intensity measurements have been obtained on a pulsed discharge lamp and the absolute Aki-values have been calculated by considering the available data from the literature as reference for the plasma temperature diagnosis. Excitation temperature (14 000–28 000 K) has been determined by using the Boltzmann-plot method. The plasma electron density (0.2–0.8 × 1023 m−3) has been determined by two-wavelength interferometry. This work extends a previous one already published by our laboratory [1, 2]. Comparisons have also been made with previous literature values.

Aims. Our aims is to measure with good accuracy the Stark parameters (width and shift) of the He I 318.8 nm (2s 3 S-4p 3 P°) line and to calibrate Stark width and shift dependencies of this line as a function of the electron density. In this way, it is possible to obtain an alternative method of diagnosing the plasmas of astrophysical origin and to check the quality of theoretical models that predict these parameters. Methods. We made a spectroscopic and interferometric analysis of a pulsed plasma. The electron temperature was obtained with an intensity ratio of He II lines and ranges from 19000 to 23000 K. Electron density was determined by interferometry ranging from 1.25 × 10 22 m -3 to 6.22 × 10 22 m -3 . Results. These experimental results are new for these plasma conditions. When joined with previous bibliographic data, they allowed us to obtain an empirical calibration expression for the Stark width and the shift of this line in a broad range of electron densities. Comparisons with different theoretical models are also included.

Red shifts and asymmetries of He II Pα 468.5682 nm and Pβ 320.3104 nm lines were measured in a pulsed plasma at an electron density measured by two-wavelength interferometry which ranges from 5.54 × 10 22 m −3 to 7.48 × 10 22 m −3 with uncertainty of 10%. Temperature ranges from 1.70 to 1.83 eV, and has been determined from intensities ratio of Pα and Pβ lines. Shifts for these lines were obtained using as reference lines Cd I 467.8149 nm and He I 318.7745 nm respectively. Measurements of asymmetries have been represented using reduced wavelength units. All results have been compared with previous experimental and theoretical data.

This work reports information on the pressure broadened profiles of the HeII P α , P β and P$_\gamma$ spectral lines measured in a pulsed discharge lamp. Information relative to the line shapes, full width at 1/2, 1/4 and 1/8 of the maximum intensity and the dip of the HeII 320.3 nm is provided. The electron density has been determined by two-wavelength interferometry and from the Stark width of the HeI 501.6 nm. and ranges during the HeII emission from 0.54 to $0.64 \times 10^{23}$ m -3 in the plasma. Temperature (1.7–2.4 eV) has been simultaneously determined from the Boltzmann-plot of HeI and from local thermodynamic equilibrium (LTE) assumptions. The final results have been compared with most of the previous existing data.

A set of experimental Stark width and shift parameters of visible singly ionized silicon spectral lines is reported in this paper. Measurements have been made on a pulsed plasma generated in a linear discharge lamp filled with a mixture of silane and helium. Electron density and temperature in this plasma range from 0.2 to 0.9 × 1023 m−3 and from 16 000 to 20 000 K respectively. Electron density has been simultaneously determined by two-wavelength interferometry and from Stark broadening of He I 501.6 nm, He I 728.1 nm and Hα lines. Temperature has been simultaneously determined from a Boltzmann plot of He I lines, from absolute emission of He I lines and from a Boltzmann plot of Si II lines. Dependences of measured Stark parameters on electron density and temperature have been investigated and the final results have been compared with most of the previous experimental data as well as with some theoretical models.

This work reports atomic transition probabilities of 33 spectral lines belonging to 3s-3p, 3p-3d and 3d-4f multiplets of O II, all of them measured in the 405-465 nm spectral region in an emission experiment. Relative intensity measurements have been made on a pulsed discharge lamp and the absolute Aki-values have been obtained taking the NIST database as a reference in temperature diagnosis. The results of this work confirm the other recent available data measured by Veres and Wiese (Veres G and Wiese W L 1996 Phys. Rev. A 54 1999) with a different source and the calculations of Bell et al (Bell K L, Hibbert A, Stafford R P and McLaughlin B M 1994 Phys. Scr. 50 343) with a very satisfactory agreement (usually within 10%).

This work reports a collection of 35 transition probabilities of lines in the spectral region 450{580 nm, all of them measured in an emission experiment. Relative intensity measurements have been made in a pulsed discharge lamp and the absolute Aki values have been obtained by using reference data taken from the literature. The electron density has been determined by two-wavelength interferometry and ranges from 0: 1t o 0:810 23 m 3 in the plasma. Temperature (14 000{24 000 K) has been simultaneously determined from three dierent methods, including the Boltzmann-plot of KrII lines and the KrII/KrI intensities ratios. The nal results have been compared with most of the previous existing data.

This work reports information about Stark broadening and shift parameters of a very extensive collection of visible singly ionized nitrogen lines. All of them were measured in a linear discharge lamp from a mixture of nitrogen and helium. Electron density and temperature range in this experiment from 0.2 to 1.1 × 1023 m-3 and from 17 000 to 29 000 K, respectively. The first one has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of He I 471.3 nm, the second from a Boltzmann plot of N II lines and from N II/N I intensity ratios. Dependences of these Stark parameters with temperature and electron density have been investigated and the final results have been compared with most of the previous experimental data as well as with two theoretical models. All relevant details relative to this experiment are given in the paper.

This work reports information about the temporal evolution of the excitation equilibrium departure in a high current pulsed arc. An argon plasma has been created in a linear lamp by discharging a capacitor bank on its electrodes. Spatially and temporally-resolved measurements have allowed us to determine electron density N e and excitation temperature T with great accuracy. Single-wavelength interferometry and H α -Stark broadening have been used to measure N e (0.2–0.98× 10 23 m -3 ). Excitation temperature has been obtained from Boltzmann-plot of ArII lines and ranges in this experiment from 13500 to 26500 K. By assuming this temperature is equal to kinetic electron temperature and by comparing the theoretically predicted and the experimental ArII/ArI intensities ratios at each instant of the plasma life, it is possible to measure the departure of the excitation processe from local them dynamic equilibrium (LTE) conditions and to show the ionizing characteristics of this close-to-LTE plasma. Different t...

Stark widths of 32 OII spectral lines have been measured, for the rst time in 16 cases to the authors' knowledge. A pulsed arc was used as a plasma source. The electron density, determined both interferometrically and spectroscopically, covers the range (2:5 7:5)10 22 m 3 . The electron temperature, determined from Boltzmann- plots, covers the range of 25000 47000 K. Possible dependencies of Stark width on the temperature have been checked. The measured widths are compared both with theoretical and experimental data available in the literature.

A very extensive compilation of Stark widths and shifts for more than 125 Ar II visible spectral lines is presented in this work. These atomic parameters have been measured in a pulsed discharge lamp by using different mixtures of pure argon or argon and helium. The electron density, which typically ranges from 0.2 to has been determined interferometrically and, in the case of pure argon plasmas, also spectroscopically from -Stark broadening. The Ar II excitation temperature (15 000-31 000 K) has been determined by Boltzmann-plot techniques from the intensity of Ar II lines. A detailed description of all the relevant points in this kind of measurement is given. Comparisons with most of the data published about this topic for Ar II are also included.

Aim: To determine the influence of surround luminance on the letter contrast sensitivity function. Method: The binocular contrast sensitivities of 31 young and ocularly healthy individuals were measured with letters of sizes calculated to obtain the targeted fundamental frequencies of 3, 10, 20, and 30 c deg-1, respectively; with surround luminances from 1 to 1000 cd m-2, always with a test chart background luminance of 200 cd m -2. Results: The letter contrast sensitivity increased with surround luminance up to 100 cd m-2 and decreased when surround luminance increased from 100 to 1000 cd m-2. These increments are larger for higher fundamental spatial frequencies, while decrements are similar for all frequencies. To analyse pupil size influence, results were compared with theoretical predictions obtained by combining different ocular MTFs with a typical neural function, where pupil size decrease leads to letter contrast sensitivity increments and veiling luminance causes the observed decrements. Other possible optical or neural factors that influence these values have also been considered. Conclusions: Letter contrast sensitivity function depends on surround luminance and this influence should be considered in future standardized directives. Fil: Juan Antonio Aparicio. No especifica; Fil: Isabel Arranz. No especifica; Fil: Beatriz Matezanz. No especifica; Fil: Juan Vizmanos. No especifica; Fil: L Padierna. No especifica; Fil: V. Gonzáles. No especifica; Fil: Juan Menéndez. No especifica; Fil: Santiago Mar. No especifica; Fil: Issolio, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Investigación en Luz, Ambiente y Visión. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Investigación en Luz, Ambiente y Visión; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; Argentina

Stark widths and shifts of 35 singly charged krypton ion spectral lines have been measured in a pulsed discharge lamp, where electron density ranges from $0.35--0.8\ifmmode\times\else\texttimes\fi{}{10}^{23}\phantom{\rule{0.3em}{0ex}}{\mathrm{m}}^{\ensuremath{-}3}$ and electron temperature ranges from $15000--27000\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. This work extends a previous one [A. de Castro et al., J. Phys. B: At. Mol. Opt. Phys. 34, 3275 (2001)] already published by our laboratory. Intramultiplet and intratransition nonregularities have been found and have been explained by considering the perturbing levels effect on the Stark parameters for each one of the measured spectral lines.

Optical diagnostics is a known and powerful tool to obtain information concerning the processes involved inside and around plasma. In the case of helium plasmas, they are present in industrial applications, like welding or cutting processes and in scientific research, like the inertial confinement plasmas or astrophysical analysis. This work reports information on the pressure broadened profiles of the HEII Paschen-alpha (Pα), Paschen-beta (Pβ) and Paschen-gamma (Pγ) spectral lines measured in a pulsed discharge lamp. Information relative to the line shapes, full width at 1/2, 1/4 and 1/8 of the maximum intensity and the dip of the HEII 320.3 nm is provided. The electron density has been determined by two-wavelength interferometry and from the Stark width of the HEI 501.6 nm and ranges during the HeII emission from 0.54 to 0.64 1023 m-3 in the plasma. Temperature (1.7 - 2.4 eV) has been simultaneously determined from the Boltzmann-plot of HEI and from local thermodynamic equilibrium (LTE) assumptions. The final results have been compared with most of the previous existing data.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are frequent techniques performed to correct ametropia. Both methods have been compared in their way of healing but there is not comparison about transmittance and light scattering during this process. Scattering in corneal wound healing is due to three parameters: cellular size and density, and the size of scar. Increase in the scattering angular width implies a decrease the contrast sensitivity. During wound healing keratocytes activation is induced and these cells become into fibroblasts and myofibroblasts. Hens were operated using PRK and LASIK techniques. Animals used in this experiment were euthanized, and immediately their corneas were removed and placed carefully into a cornea camera support. All optical measurements have been done with a scatterometer constructed in our laboratory. Scattering measurements are correlated with the transmittance -- the smaller transmittance is the bigger scattering is. The aim of this work is to provide experimental data of the corneal transparency and scattering, in order to supply data that they allow generate a more complete model of the corneal transparency.

A set of experimental Stark width and shift parameters of visible singly ionized silicon spectral lines is reported. Measurements have been made on a pulsed plasma generated in a linear discharge lamp filled with a mixture of silane and helium. Electron density and temperature in this plasma range from 0.2 to 0.9×1023 m−3 and from 16 000 K to 20 000 K, respectively. The electron density has been simultaneously determined by two-wavelength interferometry and from the Stark broadening of the He I 501.6 nm, He I 728.1 nm and Hα lines. The temperature has been simultaneously determined from a Boltzmann-plot of He I lines, from the absolute emission of He I lines, and from a Boltzmann-plot of Si II lines. Dependencies of the measured Stark parameters on electron density and temperature have been investigated.

The purpose of this work is to show a suitable plasma source and experimental arrangement for high accuracy measurement of atomic parameters developed in the Optics Department of Valladolid University. It is important to remark the careful plasma diagnostics procedures followed, and as an example we present a NII emission experiment where a very extensive collection of 104 Stark widths and 47 shifts has been measured. Electron density and temperature range from 0.2 to 1.1×1023 m−3 and from 17000 to 29000 K, respectively. All the results have been very recently published [1].

Producción Científica, This work reports an extensive collection of 108 transition probabilities of NII lines in the visible spectral region, all of them measured in an emission experiment. Relative intensity measurements have been made on a pulsed discharge lamp and the absolute Aki values have been obtained by using the literature available data. Electron density and temperature range in this experiment from 0.2 to and from 17000 to 29000 K respectively. The first one has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of HeI 471.3 nm, the second from Boltzmann-plot of NII lines and from NII/NI intensities ratios. The results are compared with the recent available literature., Ministerio de Educación y Formación Profesional (grant PB-98-0356), Junta de Castilla y León (grant VA23-99)

RESEARCH LINES OF THE OPTICS DEPARTMENTpi UNWERSITY OF VALLADOLID.Santiago Mar, Fernando Munoz, Juan Gonzalez, Angel M. de Frutos, Marco A. Gigosos, M Inmaculada de laRosa, M Concepcion Perez, Carlos Baladron, Juan Antonio Aparicio, Juan Antonio del Vat, Manuel Angel Gonzalez,Luis M Fuentes, Victor Gonzalez, Andres Bustilo, Ana Belen Gonzalo, Raal Pastor, Maria C. Gonzalez, AlbertoBarbes, Raul GarcIa, Anabel Manchon, Ricardo Vergaz, Prudencio Herrero, MarIa J. Martin, Ramon Margarida,Alberto Beijon.Dpto. Optica y Fisica Aplicada. Facultad de Ciencias.Prado de la Magdalena s/n .

This paper is an extensive experimental contribution to the knowledge of ArII atomic parameters. This specie, which is very important for many astrophysical and industrial plasma diagnostics, has been extensively studied. However, there are still great differences in the experimental Stark widths and shifts coefficients, as well as a great lack of transition probability data, especially for lines coming from the very highly excited energy levels.

We developed a model of corneal haze following photorefractive keratectomy (PRK) in Iber Braun hens and studied optical properties. The animals underwent PRK for -9.0 diopters of myopia and were divided into groups based on treatment with different wound-healing modulators. At different time points postoperatively, we evaluated haze by slit-lamp microscopy. An experimental device was developed to measure transmittance spatial maps and forward scattering of He-Ne laser light in the excised corneas. Subjective and objective haze measures were compared for each group at the different times. Keratocyte densities were determined by optical microscopy and keratocyte sizes by electron microscopy. The agreement between experimental results and a simple numerical model of scattering suggests that increases in stromal keratocyte density after PRK might explain the degree of corneal haze.

We have obtained a precise spectrum of the Balmer-alpha line, corrected for self-absorption effects, from a constant-electron-density plasma with different optical depths, in order to compare it with theoretical models and simulation techniques. The reconstruction process of the non-self-absorbed profile is highly reproducible and may be applied to both optically-thin and thick plasmas.

Stark widths and shifts of 25 visible singly ionized krypton lines are presented in this paper. All of them were measured in a pulsed discharge lamp from a mixture of krypton and helium. The electron density, which typically ranges from 0.2 to 1.8×1023 m-3 has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of the He I 388.865 nm. The excitation temperature, from 16 000 to 24 500 K, has been measured from the Boltzmann plot of Kr II lines, which has allowed us to recalculate some Kr II transition probabilities. Comparisons with most of the data published to date about this topic in Kr II are also included.

A design procedure is described to obtain monochromators for specific applications, which are made from optical devices that can be easily acquired or built. This procedure makes use of a constant angular deviation system consisting of a transmission grating, operating in a symmetrical arrangement, and a flat mirror which makes a fixed angle with it. An analysis of the characteristic parameters of the design and of the constraints which have an effect on them, is presented as well as two examples of applications of the procedure.