Miracle-dz/UniFAR-FTUs huggingface dataset:
Large Binocular Telescope Interferometer: the universal beam combiner

The Large Binocular Telescope with its single mount design and adaptive optics integrated into the secondary mirrors, provides a unique platform for mid-infrared interferometry. The Large Binocular Telescope Interferometer is designed to take advantage of this platform, specifically for extrasolar planet detection in preparation for the Terrestrial Planet Finder mission. The instrument consists of three components: a general purpose or Universal Beam Combiner (UBC) which preserves the sine condition of the array, a nulling interferometer for the LBT (NIL) to overlap the two beams and sense phase variations, and a nulling-optimized mid-infrared camera (NOMIC) for detection of the final images. Here we focus on the design and tolerancing of the UBC. The components of the system are currently being fabricated and the instrument is planned to be integrated with the LBT in 2006.
Dielectric properties of rf‐sputtered Y2O3 thin films

Yttrium oxide (Y2O3) thin films were deposited on indium‐tin‐oxide(ITO)‐coated glass substrates by the radio‐frequency‐sputtering method using an Y2O3‐sintered target. The relative dielectric constant er and the dielectric strength EBD of the Y2O3 films were studied. It was found that er and EBD have a maximum value and a minimum value, respectively, at 1.3 Pa when the pressure of the sputtering gas, Ar+10% O2, is varied from 0.67 to 9.3 Pa. The x‐ray diffraction study showed that the Y2O3 films deposited at 1.3 Pa are predominantly oriented along the 〈332〉 direction and their grain size is the smallest. Ion mass analysis showed impurity diffusion from ITO in the films deposited at 1.3 Pa. Furthermore, the dielectric properties of the Y2O3 films deposited at 1.3 Pa are related to the structural properties, such as the 〈332〉 orientation, grain size, and impurity diffusion.
The Global Precipitation Climatology Project (GPCP) combined precipitation dataset

The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5° × 2.5° latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.
Polarization-sensitive digital dermoscopy for image processing-assisted evaluation of atypical nevi: towards step-wise detection of melanoma

We have taken a three-pronged approach to improving the current standard of melanoma detection: (a) we are developing a new hyperspectral imaging-based medical device aimed at noninvasively detecting melanoma (b) we used a commercially available hand-held microscope with polarization control as a dermoscope, to begin establishing an inexpensive, portable imaging capability that could help assess the risk of a particular lesion (pigmented nevus) harboring melanoma (c) we created an updated ABCD algorithm and user interface software that more accurately generates a single risk number (Total Dermoscopy Score), for allowing a trained clinician to better assess the need for seeing the patient whose internet-uploaded nevus images they are evaluating. The hyperspectral instrument (a) is discussed elsewhere, and we focus here on (b) and (c), in the hope of increasing melanoma awareness and early detection.
Turbulence modification by compliant skin and strata-corneas desquamation of a swimming dolphin

Direct numerical simulation has been conducted for pulsating or non-pulsating turbulent water flow near the compliant wall with the separation of pieces of the surface with time to examine how much the turbulence is modified and how the drag reduction is performed in swimming dolphins. The surface consists of a model of beads, springs and dashpots to represent the stratum cornea of dolphin skin. The computational results show that the compliant wall contributes to the drag reduction by reducing the number density of hairpin vortices. The small separated pieces increase the wall shear stress, which is consistent with our experimental result for turbulent water flow over a wavy wall covered with small pieces of film. This is because the models in the linear sublayer accelerate the flow between the models and the wall. The Reynolds shear stress decreases due to the attenuation of the hairpin vortices and the Q4 events by many models transported into the buffer region. This paper was chosen from Selected Proc.
Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication

The observation of photosensitivity in Ge‐doped core optical fibers is reported. The photosensitivity is manifested by light‐induced refractive‐index changes in the core of the waveguide. Narrowband reflectors in a guide structure have been fabricated using this photosensitivity and the resulting DFB reflectors employed as laser mirrors in a cw gas laser in the visible.
A statement of Weierstrass on meromorphic functions which admit an algebraic addition theorem

A statement of Weierstrass is known for meromorphic functions which admit an algebraic addition theorem. We give its precise formulation and prove it complex analytically. In fact, we show that if K is a non-degenerate algebraic function ﬁeld in n variables over C which admits an algebraic addition theorem, then any f ∈ K is a rational function of some coordinate functions and abelian functions of other variables.
Efficient 3.3 mu m light emitting diodes for detecting methane gas at room temperature

In0.97Ga0. 03As light emitting diodes were grown on p-type InAs substrates by liquid phase epitaxy (LPE). These devices exhibit efficient infrared emission at 3.3 µm and can be used to fabricate infrared methane gas sensors for the cost-effective detection and monitoring of methane gas in various applications.
On estimating the intrinsic properties of Miras from observational data

We explore several of the consequences of the model of late stellar evolution recently investigated by Wood and Cahn. As stars ascend the asymptotic giant branch in the H-R plane, they evolve from left to right in the (M, log L) -plane, and also sink downward as they suffer a steady stellar-wind mass loss of the Reimers type. Stars in the approximate range of 1--2 M/sub sun/ eventually evolve to the point where they apparently begin first-overtone oscillation; during this phase they are Mira variables for a few hundred thousand years. At the end of their Mira stage, many of these stars evolve directly to white dwarfs; the rest of them eject one or more planetary nebulae before entering white-dwarf territory. Higher-mass stars evolve across the (M, log L) -plane without ever penetrating the Mira region and go on directly to give rise to planetary nebulae and eventually become white dwarfs. Stars of even greater mass presumably end their migration across the (M, logL) -domain by becoming supernovae. We adopt this broad picture and go on first to the Mira variables, seeking to establish an empirical diagram of period of light variation against mean spectral type at maximum light. Curvesmore » of constant period and constant spectral type are superposed on the (M, logL) -plane, along with evolutionary tracks and time scales. Thus a knowlege of the observed mean spectral type at maximum light and the period of a star permits approximate estimates to be made of its mean bolometric luminosity and present mass and gives a bird's-eve view of its past and future evolutionary track. « less
Low-threshold, quasi-cw terahertz parametric amplification in an external ring cavity with an MgO:LiNbO3 Crystal

The terahertz wave has been attracted recently because of its wide ranging applications in various fields. Since the appearance of a high power near-infrared light source, coherent terahertz waves have been generated successfully using PC antennas, Q-switch Nd:YAG laser or femto second ultrashort pulses laser. Actually, however, there is no tunable and high-reputation terahertz wave source. Then, we have been focusing on picosecond pulsed laser, because picosecond pulsed laser has smaller linewidth than femtosecond pulse and higher-reputation than Q-switch Nd: YAG laser. In addition, picosecond pulses' peak power can be enhanced in a high finesse compact external cavity to overcome the threshold of terahertz parametric generation and oscillation, because the pulse is relatively small spatially, and the spectrum is relatively narrow. Therefore, we developed a terahertz parametric generator with an MgO-doped LiNbO3(MgO: LN) nonlinear crystal in an external ring cavity for the enhancement. Moreover, the generated idler light was recycled in the ring cavity to provide a contribution to parametric oscillation. As a result, we obtained terahertz wave radiation at high-reputation of 80MHz.
The Internal Structure of a Rectangular Frame: Position, Orientation, and Direction

Previous research has shown that the structure of a rectangular frame strongly influences perceived goodness-of-fit for a small circular probe positioned within it (Palmer and Guidi, 2011). The center is consistently rated as the best position, followed by positions along the global vertical, global horizontal, and local diagonal symmetry axes. Here we report how goodness-of-fit within a surrounding frame is influenced by the relation between with the orientational and directional structure of the probe and that of the frame. In Experiment 1, fit ratings of short line segments and small ovals (each with two symmetry axes) at 35 positions and four orientations within the frame revealed strong orientational effects, especially when the probe’s and frame’s axes of symmetry were aligned. Experiment 2 extended the paradigm using triangular probes (with a single symmetry axis) at 15 positions and eight pointing directions. The results showed high fit ratings when the probe was aligned with global and local symmetry axes of the frame, and directional increments when the probes pointed upward, rightward, and into the frame. Experiment 3 confirmed the upward, rightward, and inward directional effects of Experiment 2 using a more sensitive Two-Alternative Forced Choice (2AFC) task. Experiment 4 showed that orientational effects were more strongly driven by alignment with the rectangle’s sides than with gravitational or retinal reference frames, especially when the probe was near the sides and vertices of the frame. The relevance of these findings to the empirical study of aesthetic response to images within rectangular frames is discussed.
TOGA COARE: The Coupled Ocean-Atmosphere Response Experiment.

Despite significant progress in the Tropical Ocean–Global Atmosphere (TOGA) program, a number of major hurdles remain before the primary objective, prediction of the variability of the coupled ocean-atmosphere system on time scales of months to years, can be achieved. Foremost among these hurdles is understanding the physics that maintains and perturbs the western Pacific warm pool, the region of the warmest sea surface temperature in the open oceans, which coexists with the largest annual precipitation and latent heat release in the atmosphere. Even though it is believed that the warm pool is a “center of action” for the El Nino-Southern Oscillation (ENSO) phenomena in the ocean and the atmosphere, successful simulation of the warm pool has remained an elusive goal. To gain a clear understanding of global climate change, the ENSO phenomenon, and the intraseasonal variability of the coupled atmosphere–ocean system, it is clear that a better specification of the coupling of the ocean and the atmosphere is .
Physical Explanation of Tropospheric Aerosol Effects on Twilight Sky Color Based on Photographic Observations and Radiative Transfer Simulations

The relationship between the twilight sky and atmospheric state has been studied for the past 50 years, providing a good understanding of the general picture of the radiative transfer process under twilight conditions. However, tropospheric aerosols may strongly affect the spectral characteristics of the twilight glow near the horizon under clear-sky conditions, and the mechanism of this phenomenon is not well understood because of its high complexity. In this study, we observed the twilight sky using a digital camera and calculated the spectral radiance of the twilight sky using a radiative transfer model (RTM). Photographic observations aided by several ground-based radiometric measurements revealed that tropospheric aerosols significantly influenced the twilight sky color. In particular, the sky near the horizon became darker and bluer with increasing aerosol optical depth (AOD), which was consistent with the RTM simulations. The RTM simulations also showed for the first time that bluish multiply scattered light dominated the twilight sky near the horizon and reddish singly scattered light decreased with increasing tropospheric AOD. These simulation results suggest that photographic observations have the potential to characterize tropospheric aerosols under twilight conditions. (Citation: Saito, M., H. Iwabuchi, and T. Hayasaka, 2013: Physical explanation of tropospheric aerosol effects on twilight sky color based on photographic observations and radiative transfer simulations. SOLA, 9, 15−18, doi:10.2151/sola.2013-004.)
Shift in the percolation threshold of compressed composites—A 3D Monte Carlo simulation

The shift in the percolation threshold of compressed composites was studied by a 3D continuum percolation model. A Monte Carlo (MC) method was employed in the simulations. The percolation threshold was found to rise with the compression strain, which captures the basic trend in compression-induced conductivity variation from the experiments. Both fiber bending and texture formation contribute to the percolation threshold. The results suggest that fillers with a high aspect ratio are more desirable for sensor and electrical switch applications.
The nature of the Napoleon's Hat nebula of SN 1987A

Recent observations of the Napoleon's Hat nebula of SN 1987A show that it can be described by a bow shock on the northern side of the supernova. Because of its location close to the supernova, Napoleon's Hat is doubtless affected by the wind from the precursor. It has previously been shown that the supernova is located at the top of a cocoon-shaped dark bay. By modelling the structure and dynamical formation of Napoleon's Hat and the dark bay, we conclude that the supernova progenitor star was in motion with respect to its circumstellar environment. The dark bay was produced by the shock interaction between the interstellar medium and the energetic wind of the precursor when in its main-sequence stage
Hannay angle study of the Foucault pendulum in action‐angle variables

The Hamiltonian is derived for the Foucault pendulum in polar coordinates in terms of the action variables of the system. The complete solution to the Foucault pendulum is found in the small oscillation limit from the action‐angle approach. During a cycle of adiabatic change (one revolution of the earth), the polar angle change can be divided into a dynamic phase and a geometric phase, called the Hannay angle, which is independent of the duration of the adiabatic change. It is shown that the Hannay angle is equal to the solid angle swept out by the pendulum axis. Four special solutions arising from different initial conditions are considered and serve to clarify the meaning of the action variables. Other coordinate systems for which separation of variables is possible are discussed. In these doubly rotating systems, the Hannay angle is shown to vanish.
Time-resolved fluorescence and photon migration studies in biomedical and model random media

This review highlights time-resolved fluorescence kinetics and photon transport in tissues and other biomedical media with a special emphasis on ultrafast measurements of key optical parameters. Measurements of fluorescence decay lifetimes from human breast and atherosclerotic artery tissues in the uv and visible region are described after a brief description of fundamentals of fluorescence kinetics. A time-dependent diffusion model for photon migration and various ultrafast methods for time-resolved light scattering measurements to obtain key optical parameters of tissues and other model turbid media are presented. The usefulness of optical parameters as markers in optical diagnostics and imaging is considered. Time-gated measurements of ballistic and snake photons to obtain shadowgrams and an inverse numerical reconstruction of the interior map of a turbid medium from time-resolved data in the context of optical tomography are presented.
VLBA Snapshot Imaging Survey of Scintillating Sources

We present 8.4 GHz Very Long Baseline Array (VLBA) observations of 75 extragalactic radio sources drawn from the scintillating sources discovered in the Microarcsecond Scintillation-induced Variability survey. This survey clearly showed that the fraction of scintillating sources and the amplitude of their variability increases strongly with decreasing flux density, raising the possibility that scintillating sources may be systematically extremely core dominated. The observations presented here were designed to investigate this hypothesis. The results indeed show that most of the scintillating sources we observed with the VLBA have an extremely compact, core-dominated morphology, which has important implications for interpretations of the scintillation seen in these sources. In addition, these sources are potential candidates for inclusion in the International Celestial Reference Frame.
The initial growth of disturbances in a baroclinic flow

Abstract The growth of perturbations in a baroclinic flow is examined as an initial value problem. Although the long time asymptotic behavior is dominated by discrete exponentially growing normal modes when they exist, these do not form a complete set and initial intensification is shown to be dependent on the continuous spectrum. The vertical structure of perturbations emerges as an important influence on initial growth, and physically realistic disturbances are shown to grow to amplitudes where nonlinear effects are important before obtaining normal mode form. Connection is made with the work of Arnol'd (1965) and Blumen (1968) and the numerical experiments of Simmons and Hoskins (1979). Application of these results to cyclogenesis in geographically fixed areas is suggested and implied constraints on numerical models discussed.
A Class of Improved Heteroskedasticity-Consistent Covariance Matrix Estimators

Abstract The heteroskedasticity-consistent covariance matrix estimator proposed by White [White, H. A. (1980). Heteroskedasticity-consistent covariance matrix estimator and a direct test for heteroskedasticity. Econometrica 48:817–838], also known as HC0, is commonly used in practical applications and is implemented into a number of statistical software. Cribari–Neto et al. [Cribari–Neto, F. , Ferrari, S. L. P., Cordeiro, G. M. (2000). Improved heteroscedasticity–consistent covariance matrix estimators. Biometrika 87:907–918] have developed a bias-adjustment scheme that delivers bias-corrected White estimators. There are several variants of the original White estimator that are also commonly used by practitioners. These include the HC1, HC2, and HC3 estimators, which have proven to have superior small-sample behavior relative to White's estimator. This paper defines a general bias-correction mechamism that can be applied not only to White's estimator, but to variants of this estimator as well, such as HC1, HC2, and HC3. Numerical evidence on the usefulness of the proposed corrections is also presented. Overall, the results favor the sequence of improved HC2 estimators.
Nonparametric Estimation of Nonstationary Spatial Covariance Structure

Abstract Estimation of the covariance structure of spatial processes is a fundamental prerequisite for problems of spatial interpolation and the design of monitoring networks. We introduce a nonparametric approach to global estimation of the spatial covariance structure of a random function Z(x, t) observed repeatedly at times ti (i = 1, …, T) at a finite number of sampling stations xi (i = 1, 2, …, N) in the plane. Our analyses assume temporal stationarity but do not assume spatial stationarity (or isotropy). We analyze the spatial dispersions var(Z(xi, t) − Z(xj, t)) as a natural metric for the spatial covariance structure and model these as a general smooth function of the geographic coordinates of station pairs (xi, xj ). The model is constructed in two steps. First, using nonmetric multidimensional scaling (MDS) we compute a two-dimensional representation of the sampling stations for which a monotone function of interpoint distances δij approximates the spatial dispersions. MDS transforms the problem.
Phenomenological model with application for polarization-sensitive semiconductor optical amplifiers

We introduce a phenomenological model to describe polarization-sensitive SOAs which is composed of a partly linear polarizer, a retarder, and a polarization independent amplifier. It shows that any input optical vector of signal will first be partly linearly polarized, then rotate around S1-axis of the Poincaré sphere for θ, and finally be amplified equably. Then we investigate and experimentally demonstrate the relationship between polarization rotation (PR) and mode gains. We further obtain two necessary conditions for the valuable orthogonal polarization rotation (OPR), and then perform a power-equalized OPR by optical-electric synchronous control of the SOA. The polarization duration time is ~10 ns which is applicable to high-speed polarization state generation.
Modeling and analysis of multijunction solar cells

The modeling of high efficiency, multijunction (MJ) solar cells away from the radiative limit is presented. In the model, we quantify the effect of non-radiative recombination by using radiative efficiency as a figure of merit to extract realistic values of performance under different spectral conditions. This approach represents a deviation from the traditional detailed balance approximation, where losses in the device are assumed to occur purely through radiative recombination. For lattice matched multijunction solar cells, the model predicts efficiency values of 37.1% for AM0 conditions and 52.8% under AM1.5D at 1 sun and 500X, respectively. In addition to the theoretical study, we present an experimental approach to achieving these high efficiencies by implementing a lattice matched triple junction (TJ) solar cell grown on InP substrates. The projected efficiencies of this approach are compared to results for the state of the art inverted-metamorphic (IMM) technology. We account for the effect of metamorphic junctions, essential in IMM technology, by employing reduced radiative efficiencies as derived from recent data. We show that high efficiencies, comparable to current GaAs-based MJ technology, can be accomplished without any relaxed layers for growth on InP, and derive the optimum energy gaps, material alloys, and quantum-well structures necessary to realize them.