Growth, characterization, and waveguide lasing of Yb3+, Lu3+, Gd3+ co-doped KY(WO4)2 thin layers

Monoclinic crystals of KY(WO4)2 (KYW) doped with different rare-earth ions are among the highly promising materials for building compact solid-state lasers. \ud We report the liquid phase epitaxy (LPE) growth of 3-5 µm thick KYW:Gd3+, Lu3+, Yb3+ layers for Yb3+ concentrations of 1.2, 1.7, and 2.4 mol% and 30 to 40-µm-thick KYW:Gd3+, Yb3+ (20 mol%) layers. The concentration of the dopants Yb3+, Lu3+, and Gd3+ in the grown film were determined by laser ablation inductively coupled plasma - mass spectrometry (LA-ICP-MS). The growth conditions were optimized, leading to crack-free layers for all investigated Yb3+ concentrations. X-ray investigations have confirmed the high crystallinity of the films.\ud Based on the Gd3+, Lu3+ co-doped thin films, planar waveguide lasers operating on the Yb3+ transition at 1025 nm were demonstrated. Due to the co-doping, resulting in high refractive-index difference between film and substrate, very thin waveguides with strong light confinement were obtained, thus allowing for a pump threshold of laser operation as low as 18 mW. The highest slope efficiency versus absorbed pump power and output power were 82.3% and 195 mW, respectively

A secondary ejecta explanation of a lunar seismogram

Secondary ejecta explanation to seismograph of Apollo 12 LM impac

Mechanical and analytical screening of braided composites for transport fuselage applications

The mechanics of materials progress in support of the goal of understanding the application of braided composites in a transport aircraft fuselage are summarized. Composites consisting of both 2-D and 3-D braid patterns are investigated. Both consolidation of commingled graphite/PEEK and resin transfer molding of graphite-epoxy braided composite processes are studied. Mechanical tests were used to examine unnotched tension, open hole tension, compression, compression after impact, in-plane shear, out-of-plane tension, bearing, and crippling. Analytical methods are also developed and applied to predict the stiffness and strengths of test specimens. A preliminary study using the test data and analytical results is performed to assess the applicability of braided composites to a commercial aircraft fuselage

Berry-phase blockade in single-molecule magnets

We formulate the problem of electron transport through a single-molecule magnet (SMM) in the Coulomb blockade regime taking into account topological interference effects for the tunneling of the large spin of a SMM. The interference originates from spin Berry phases associated with different tunneling paths. We show that in the case of incoherent spin states it is essential to place the SMM between oppositely spin-polarized source and drain leads in order to detect the spin tunneling in the stationary current, which exhibits topological zeros as a function of the transverse magnetic field.Comment: 4 pages, Revtex 4, 4 EPS figure

Towards the QCD phase diagram from analytical continuation

We calculate the QCD cross-over temperature, the equation of state and fluctuations of conserved charges at finite density by analytical continuation from imaginary to real chemical potentials. Our calculations are based on new continuum extrapolated lattice simulations using the 4stout staggered actions with a lattice resolution up to $N_t=16$. The simulation parameters are tuned such that the strangeness neutrality is maintained, as it is in heavy ion collisions.Comment: 4 pages, 2 figures, Proceedings of the Quark Matter 2015 conference, Kobe, Japa

Radiographic and ultrasonographic evaluation of the esophagus in the horse

The purpose of this study was to describe the radiographic and ultrasonographic appearance of the esophagus of ten healthy horses. Contrast radiography showed variations in the long-axis shape of the esophagus at the thoracic inlet. Administration of a large volume contrast medium by intubation showed stasis of contrast material for several minutes in two of the ten horses. The wall thickness of the non-distended esophagus on ultrasound was 2.6 +/- 0.3 mm with significant differences depending on the location. Distention of the esophagus by intubation or by a bolus of water or concentrate resulted in a decrease in wall thickness and it facilitated measuring with less variation. Stasis at the thoracic inlet was seen in five of the ten horses, when a water bolus was administered. Ultrasonographic evaluation of 100g spontaneously swallowed commercial concentrate was better than fluid (water bolus or 2.5mL/kg contrast medium) administration via intubation to assess esophageal motility at the thoracic inlet. Stasis seen at the thoracic inlet after bolus administration by intubation should not be regarded as an abnormal finding, and swallowing, with the subsequent peristaltic wave, has a positive influence on the bolus passage time

Estimation of Autoregressive Parameters from Noisy Observations Using Iterated Covariance Updates

Estimating the parameters of the autoregressive (AR) random process is a problem that has been well-studied. In many applications, only noisy measurements of AR process are available. The effect of the additive noise is that the system can be modeled as an AR model with colored noise, even when the measurement noise is white, where the correlation matrix depends on the AR parameters. Because of the correlation, it is expedient to compute using multiple stacked observations. Performing a weighted least-squares estimation of the AR parameters using an inverse covariance weighting can provide significantly better parameter estimates, with improvement increasing with the stack depth. The estimation algorithm is essentially a vector RLS adaptive filter, with time-varying covariance matrix. Different ways of estimating the unknown covariance are presented, as well as a method to estimate the variances of the AR and observation noise. The notation is extended to vector autoregressive (VAR) processes. Simulation results demonstrate performance improvements in coefficient error and in spectrum estimation

The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures

Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities

Bayesian Compressive Sensing of Sparse Signals with Unknown Clustering Patterns

We consider the sparse recovery problem of signals with an unknown clustering pattern in the context of multiple measurement vectors (MMVs) using the compressive sensing (CS) technique. For many MMVs in practice, the solution matrix exhibits some sort of clustered sparsity pattern, or clumpy behavior, along each column, as well as joint sparsity across the columns. In this paper, we propose a new sparse Bayesian learning (SBL) method that incorporates a total variation-like prior as a measure of the overall clustering pattern in the solution. We further incorporate a parameter in this prior to account for the emphasis on the amount of clumpiness in the supports of the solution to improve the recovery performance of sparse signals with an unknown clustering pattern. This parameter does not exist in the other existing algorithms and is learned via our hierarchical SBL algorithm. While the proposed algorithm is constructed for the MMVs, it can also be applied to the single measurement vector (SMV) problems. Simulation results show the effectiveness of our algorithm compared to other algorithms for both SMV and MMVs