Metal-organic deposition of YBCO and BSCCO platelets,films and wires

Il Nuovo Cimento D - Metal-Organic Deposition (MOD) technique has been used for the first time, in the spray version, to obtain thin and thick films of BSCCO on substrates like MgO and Ag and, in...     

Use of apodization in quantitative spectroscopy

Apodization, which is a tool frequently used for cosmetic representation and efficient modeling of a spectrum, is now also adopted in techniques for the quantitative retrieval of parameters from observed spectra. Whether apodization can help in quantitative spectroscopy is the subject of debate in the literature. We find that, when the considered spectral range is wide enough to accurately model the instrument line shape, the same results can be obtained with and without apodization of the spectrum. However, when a truncation error is introduced by the limited extension of the modeled spectral interval, apodization can efficiently reduce this error. Therefore it is possible to save computing time by using apodization.     

Influence of steady background gradients on the accuracy of molecular diffusion anisotropy measurements

Spatial susceptibility variations of body components lead to local gradients of the static magnetic field. Effects of such background gradients on fractional diffusion anisotropy (FA) measurements on whole-body magnetic resonance units operating at 1.5, 3.0 and 7.0 T were analyzed theoretically and experimentally. Analytical expressions were derived for the cases of diffusion occurring in isotropic media and in tissues with cylindrical symmetry (e.g., white matter tracts or skeletal musculature). Typical magnitudes of background gradient strengths were estimated from in vivo and in vitro measurements with B0 field mapping sequences. Additionally, numerical simulations of magnetic field distributions and resulting field gradients were performed considering tissue-air interfaces in simplified geometrical arrangements. For media with isotropic diffusion, both measurements and analytical calculations showed increasing FA inaccuracy with stronger coupling between diffusion-encoding and background gradients. For cylindrical symmetry, FA values were estimated for a standard diffusion tensor imaging protocol in a realistic scenario. At 1 mm distance from a water-air interface, susceptibility-related background gradients amount to approximately 9 mT/m at 7 T and lead to a relative error of the measured FA of up to 48%. The error in the anisotropy assessment rises considerably with increasing field strength and must be taken into account especially for experimental and clinical studies on modern high-field systems.     

First measurement of the strange particles R CP nuclear modification factors in heavy-ion collisions at the SPS

The NA57 experiment has measured the p _T distributions of K _S ^O , Λ, and $\bar \Lambda $ particles in fixed-target Pb?Pb interactions at √s _NN=17.3 GeV, as a function of the collision centrality. In this paper we study the central-to-peripheral nuclear modification factors and compare them to other measurements and to theoretical predictions.     

The Application of Heat Treatment in the Formation of Relief-Phase Holographic Structures on Dichromed Gelatin

Optics and Spectroscopy - A new method of formation of relief-phase holographic structure on dichromated gelatin (DCG) layers has been proposed. The method is based on two types of alternative...     

Optical pulse broadening in long fibre waveguides

As a result of research, the propagation characteristics of optical waveguides are becoming well enough understood for system evaluation. In this paper material and structural properties of the waveguide are related to measurements made on present experimental waveguides. Among the conclusions drawn from this work are that intermodal dispersion provides the dominant pulse broadening contribution but that this has been reduced to the nanosecond region by radial index gradient control. For present source spectral bandwidths, material dispersion is not a major contribution to pulse broadening. Waveguides up to 3 km long can be made with negligible intrinsic mode coupling. This gives rise to the possibility of either internal or external control to increase the information carrying capacity of the waveguide. External control has already been demonstrated. However, additional work is required to make this practical.     

Analytical Expressions of Thermodynamic and Transport Properties of the Martian Atmosphere in a Wide Temperature and Pressure Range

Calculation of thermodynamic and transport properties of CO₂/N₂/O₂/Ar system (Martian atmosphere) have been performed in a wide pressure (0.01–100 bar) and temperature range (50–50,000 K). A self-consistent approach for the thermodynamic properties and higher order approximation of the Chapman–Enskog method for the transport coefficients have been used. Debye–Hückel corrections have been included in the calculation of thermodynamic properties while collision integrals derived following a phenomenological approach and accounting also for resonant processes contributions have been used. Moreover, charge–charge interactions have been obtained by using a screened Coulomb potential. Calculated values have been fitted by closed forms ready to be inserted in fluid dynamic codes in order to simulate plasma conditions for different technological applications. Comparison with data present in literature is also reported.