Miracle-dz/UniFAR-FTUs huggingface dataset:
Zone plate EUV solar irradiance monitor

Measuring the solar extreme ultraviolet (EUV) irradiance is a high priority for space weather and upper atmospheric research. We have designed and fabricated a sensor to measure the total solar irradiance in the extremely variable 17.1- 19.5 nm spectral band that contains numerous Fe emission lines and we are developing another similar sensor for the 30.4 nm He II spectral line. Each of these sensors uses a 4 mm diameter zone plate (ZP) to focus the in-band solar radiation onto a small pinhole in front of a detector. The focal length of a ZP is inversely proportional to wavelength, and the pinhole's diameter is sufficient to admit the in-band radiation from the full solar disk and inner corona. A 2 mm diameter central occulting disk minimizes the undiffracted (0-order) and out-of-band radiation that reaches the pinhole. Two thin Al film filters, one in front of the ZP and one deposited on the detector, are virtually opaque to wavelengths longer than EUV and prevent the detector from responding to most of the solar spectrum. A ZP has a number of advantages over a diffraction grating. Because it focuses in-band radiation, a ZP allows the detector to be smaller than the aperture, reducing both the dark current and the out-of-band response. The circular symmetry of the ZP eliminates both the polarization sensitivity and the shift in the spectral band with field angle that are intrinsic to a linear grating. The optical assembly is contained in a very small volume. We are planning to fly the Fe-band sensor as a secondary payload on NRL's VERIS sounding rocket solar measurement mission in the near future and are investigating the feasibility of flying both sensors on a future CubeSat mission.
On the ductile response dependence upon phase transformation in diamond turning of semiconductors

It is well established that during machining, materials with lower hardness presents higher ductility. However, in the machining of semiconductor crystals the brittle to ductile transition may not strictly follow this rule. This paper intends to show that the extent of the ductile response of monocrystalline semiconductors can not be related to its microhardness value, since the plastic behavior of semiconductor crystals is related to a phase transformation induced by pressure/stress. This was investigated by carrying out microindentation and single point diamond turning tests in three different semiconductors, InSb, GaAs and Si[001]‐oriented single crystals. Based upon tests results it is observed that the onset of brittle behavior is brought forward to semiconductors with higher transition pressure value. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High-resolution structural studies and covalent bond interactions in BiFeO3-PbTiO3 compounds: The role of ferroism

The origin of enhanced ferroism in La-modified BiFeO3-PbTiO3 compounds is investigated by examining chemical bonding in high-resolution structural measurements. It is shown that structural modifications in the perovskite A-site, such as absent or inactive lone-pair ions, lead to reduced covalence in A-O bonds and increased covalence in B-O bonds for the tetragonal phase. This change in bond character results in a structural accommodation that favors the rhombohedral over the tetragonal phase, which also enhances the ferroic properties. These observations highlight the influence of modifiers on BiFeO3-PbTiO3 bonds and phase stabilization mechanisms.
Temperature dependence of reverse-bias leakage current in GaN Schottky diodes as a consequence of phonon-assisted tunneling

Temperature-dependent reverse-bias current-voltage data obtained by Miller et al. [Appl. Phys. Lett. 84, 535 (2004)] for Schottky diodes fabricated on n-GaN are reinterpreted in terms of a phonon-assisted tunneling model. It is shown that the temperature dependence of the reverse-bias leakage current may be caused by the temperature dependence of the electron tunneling rate from traps in the metal-semiconductor interface to the conduction band of the semiconductor. A good fit of the experimental data with this theoretical model is obtained in the entire temperature range from 80to400K, when an effective mass of 0.222me and a phonon energy of 70meV are used for the calculation. The reverse current-voltage data for GaN diodes are also explained on the basis of this model.
Modelling Uncertainty and Overdispersion in Ordinal Data

In this article we introduce a probability distribution generated by a mixture of discrete random variables to capture uncertainty, feeling, and overdispersion, possibly present in ordinal data surveys. The choice of the components of the new model is motivated by a study on the data generating process. Inferential issues concerning the maximum likelihood estimates and the validation steps are presented; then, some empirical analyses are given to support the usefulness of the approach. Discussion on further extensions of the model ends the article.
Current-voltage characteristics and breakdown mechanism in one-dimensional band and mott insulators attached to electrodes

The current-voltage characteristics and mechanism of bias-induced breakdown in one-dimensional models for band and Mott insulators are investigated theoretically by using nonequilibrium Green’s functions. We attach the models to metallic electrodes, the effects of which are incorporated into the self-energy. For the models of both the band and the Mott insulators with lengths LC, the bias voltage induces a breakdown of the insulating state, and the breakdown mechanism shows a crossover depending on LC. When LC is smaller than the correlation length ξ = W/Δ, the threshold is determined basically by the bias Vth ∼ Δ, where W and Δ are the bandwidth and the energy gap, respectively. For systems with LC ≫ ξ, the threshold is governed by the electric field, Vth/LC, which is consistent with a Landau-Zener-type breakdown Vth/LC ∝ Δ2/W.
Trapped‐Energy Modes in Quartz Filter Crystals

The behavior of thickness/shear‐mode quartz resonators is explained both mathematically and experimentally in terms of lateral standing‐wave trapped‐energy modes. A cutoff phenomenon, similar to that occurring in optical total internal reflection, results in energy trapping or the restriction of vibratory energy almost exclusively to the electroded region of a resonator, with an energy distribution decreasing exponentially with distance from the electrode edge. Consideration of boundary conditions at the electrode edges of an idealized two‐dimensional model yields an expression for the eigenfrequencies of symmetric inharmonic overtone modes (lateral standing waves) that can exist in the electroded region of fundamental‐ and harmonic‐mode resonators. Design formulas for the suppression of these unwanted modes are included. They show that electrode thickness and lateral dimensions can be traded off against one another to obtain a wide range of motional parameters. Previously, unwanted responses were elimina.
Narrowing of the frequency-linewidth in structured magnetic strips: Experiment and theory

We examine the frequency-linewidth in structured magnetic materials experimentally and theoretically and show that this linewidth can decrease as the external field (or the frequency) is increased. This decrease in the frequency-linewidth occurs in many different systems and does not indicate an increase in damping at low frequencies, as has been suggested. Further, the frequency-linewidth can be very large for extended ferromagnetic films, but becomes significantly smaller for structured films that are narrower than a few microns.
A Micromechanics-Based Model for Creep Behavior of Rock

Recently, various ideas on underground development have been proposed and associated technical problems have been studied. One of the issues of concern is the prediction of the long-term behavior of rock, such as creep phenomena and fatigue. The mechanical behavior of rock is known to be greatly affected by temperature, confining pressure, pore fluid pressure and pH. It is necessary to establish a prediction method for creep deformation and creep failure of rock in order to ensure the long-term safety of the underground structures such as vaults for nuclear waste and power stations. Studies with the scanning electron microscope revealed that the mechanisms of creep deformation and creep failure is the growth of microcrack nucleated at a pre-existing defect. Under compression below the failure strength, the microcrack gradually grows and the rock specimen fails after a certain time. The mechanism of time-dependent crack growth is understood as the stress corrosion at the crack tips. The objective of this study is to establish a prediction method of creep behavior. It is necessary to understand the governing mechanism of phenomena and to build a model for the reproduction of creep behavior. In this study, an analytical model of microcrack growth under compressionmore » on the basis of micromechanics is proposed. The analytical results of the proposed model are compared with the experimental results. It appears that the experimental data are reproduced by the model. Moreover, a constitutive equation is derived from the proposed micromechanical model and is implemented into a finite element program to analyze the creep behavior of underground structures. As an example, a problem of elliptical excavation under hydrothermal conditions is analyzed and a crack length field is predicted as a function of time at different temperatures. It is concluded that the results of the finite element analysis indicate the possibility that rock may fail due to the effect of high temperature. « less
Spectroscopy of low-coordinated surface sites: Theoretical study of MgO

We demonstrate a dramatic dependence on the oxygen coordination of the calculated optical absorption and luminescence energies of low-coordinated sites at the surfaces and in nanoclusters of MgO. The calculations for (MgO)(256) cubic nanoclusters were performed using an embedded molecular cluster model and both semiempirical and ab initio Hartree-Fock methods. The optical-absorption energies were calculated using the configuration interaction technique for single (CIS) and double electronic excitations. The luminescence energies were calculated using the CIS method. The low-coordinated sites included corners, kinks, step and cluster edges, and corner vacancy defects. We have also studied the zigzag steps and monatomic steps at infinite surfaces using a periodic density-functional theory method and a plane-wave basis set. For both the nanoclusters and infinite surfaces, the results show a consistent significant reduction of the exciton excitation energies and of the luminescence energies of relaxed excitons as the oxygen coordination decreases. We also demonstrate the possibility of exciton transfer from the sites with higher coordination to those with lower coordination and finally to the localization centers. Selective optical excitation of low-coordinated surface sites could be used to study molecular adsorption at surface sites, photocatalytic surface processes and desorption induced by electronic transitions. [S0163-1829(99)07203-3].
Prevalent Lq-dimensions of measures

Abstract Let K be a compact subset of ℝd and write s for the Hausdorff dimension of K. For a probability measure μ on K, the lower and upper Lq-dimensions of order q ∈ ℝ are defined by \begin{eqnarray*} \underline D_{\mu}(q) &=& \liminf_{r\searrow0}\, \frac{\log \displaystyle \int_{\supp\mu} \mu(B(x,r))^{q-1} \,d\mu(x)} {-\log r},\\ \overline D_{\mu}(q) &=& \limsup_{r\searrow0} \frac{\log \displaystyle \int_{\supp\mu} \mu(B(x,r))^{q-1} \,d\mu(x)} {-\log r}. \end{eqnarray*} In this paper we study Lq-dimensions of measures that are generic in the sense of prevalence. In particular, we prove that if K satisfies a mild regularity condition, then a prevalent probability measure μ on K satisfies: \[ \underline D_{\mu}(q) = \overline D_{\mu}(q) = s(1-q), \] for all 0 ≤ q ≤ 1, and \[ \underline D_{\mu}(q) = \overline D_{\mu}(q) = 0, \] for all 1 ≤ q. This result is in sharp contrast to the behaviour of the Lq-dimensions of measures that are generic in the sense of Baire category. Namely, if K satisfies a mild regularity condition, then a probability measure μ on K that is generic in the sense of Baire category satisfies: \[ \underline D_{\mu}(q) = s(1-q) < 0 = \overline D_{\mu}(q) \] for all 1 < q.
Combinatorial and algebraic tools for optimal multilevel algorithms

This dissertation presents combinatorial and algebraic tools that enable the design of the first linear work parallel iterative algorithm for solving linear systems involving Laplacian matrices of planar graphs. The major departure of this work from prior suboptimal and inherently sequential approaches is centered around: (i) the partitioning of planar graphs into fixed size pieces that share small boundaries, by means of a local "bottom-up" approach that improves the customary "top-down" approach of recursive bisection, (ii) the replacement of monolithic global preconditioners by graph approximations that are built as aggregates of miniature preconditioners. In addition, we present extensions to the theory and analysis of Steiner tree preconditioners. We construct more general Steiner graphs that lead to natural linear time solvers for classes of graphs that are known a priori to have certain structural properties. We also present a graph-theoretic approach to classical algebraic multigrid algorithms. We show that their design can be recast as the construction of Steiner graph preconditioners. This observation makes algebraic multigrid amenable to a combinatorial approach that provides natural graph-theoretical goals and provably fast parallel algorithms for the design of the two-level scheme.
Infrared photometric and spectrophotometric observations of the galactic H II region G29.9-0.0.

Spatial, photometric, and spectrophotometric observations of the compact H ii region G29.9--0.0 are reported. The photometric observations indicate that the infared object agrees in position and size with the radio source. Spectrophotometry from 8--13 $mu$ shows a broad absorption feature, as well as fine-structure emission lines of Ar$sup ++$ and Ne$sup +$. Model fits to the spectrum of G29.9--0.0 indicate that three is strong absorption throughout the 8- 13 $mu$ spectral region. The photometry indiates that dust competes with the gas for absorbing the ionizing stellar continuum, while there is evidence for a depletion of dust within the ionized region. A comparison of 2.2 $mu$-10 $mu$ extinction to the source indicates that A/subv//tau$sub 9$. $sub 75$/sub mu/>6 mag.
Generation and communication of photon-photon and atom-atom entangled states

We introduce and discuss two schemes for generation and transfer of photon-photon and atom-atom entanglement. First we propose a method to achieve a large conditional phase shift of a probe field in the presence of a single-photon control field whose carrier frequency is within the photonic band gap created by spatially-periodic modulation of the electromagnetically induced transparency resonance. Then we present the concept of a reversible transfer of the quantum state of two internally-translationally entangled fragments, formed by molecular dissociation, to a photon pair. Our scheme allows, in principle, high-fidelity state transfer from the entangled dissociated fragments to light, thereby producing a highly correlated photon pair. This process can be followed by its reversal at a distant node of a quantum network resulting in the recreation of the original two-fragment entangled state. The proposed schemes may have advantageous applications in quantum teleportation, cryptography, and quantum computation.
A study of push-pull parametric transformer

The parametric transformer has voltage regulation, overload protection, and a kind of filter function for harmonic currents produced by nonlinear loads. The operating characteristics of the push-pull parametric transformer with resistive load are discussed. Furthermore, the authors demonstrate the operation of the push-pull parametric transformer with a thyristor rectifier circuit as an example of a nonlinear load. The authors propose an application of the transformer as a power supply for suppressing higher harmonic currents produced by nonlinear loads such as the thyristor rectifier circuit. >
Finite length and solvent analysis effects on the squash mode of single walled carbon nanotubes

Nanotube diameters (d) are usually characterized using the radial breathing mode d–1; the squash mode frequency (f) however is predicted to vary as d–2. We demonstrate using the MM+ forcefield that for lengths <9 nm the symmetric squash mode (SSM) and asymmetric squash mode (ASM) ((10,0) SWNT (single wall carbon nanotubes)) are non-degenerate with Δf ≤ 55 cm–1. In solution, the SWNT-water interaction upshifts the ASM by 20 cm–1 and the SSM by 10 cm–1. Such asymmetries could be used to simultaneously characterize the length and diameter of short nanotubes for applications including nanoresonators and biomedical probes.
Index Theorems for Gauge Theories

We review the topological invariants that count supersymmetric states for gauge theories, with an emphasis on string theory applications. In particular, the enumerative index and the twisted partition functions are carefully distinguished by how continuum sectors are handled. The recent localization routine has led to a systematic computation of the latter, and we offer a mechanism for extracting the truly enumerative indices when the continuum sector originates in the Coulomb branch. This leads to a satisfactory conclusion of a twenty-year saga of D0-brane bound state problems. We close with broad comments on how the wall-crossing manifests in the index theorems, and define the Quiver/GLSM invariants, which are entirely immune under the wall-crossing.
Rheology of Adsorbed Surfactant Monolayers at Fluid Surfaces

When surfactants adsorb at liquid surfaces, they not only decrease the surface tension, they also confer rheological properties to the surfaces. The most common rheological parameters are the surface compression elasticity and viscosity and the surface shear viscosity. These parameters usually depend on the timescale of the deformation, owing to surface relaxations, and on its amplitude, owing to nonlinear responses. In addition, surfactants can exchange between the bulk and surface, in a way that depends on the amount of bulk surfactant locally available. This complexity explains why the topic has progressed slowly over the years. This review describes the current knowledge, focusing on recent advances, and gives examples of phenomena in which surface rheology plays an important role.
Gaussian diffusion sphere model to predict deposition velocities under the combined effects of electrophoresis and thermophoresis

The Gaussian diffusion sphere model (GDSM) is proposed to predict the average deposition velocity of particles onto a flat plate exposed to parallel airflow after considering the combined effects of electrophoresis and thermophoresis. This model can account for convection, Brownian diffusion, gravitational settling, thermophoresis, and electrophoresis, and it provides fast calculation times and accurate predictions. Using the GDSM, the effects of the deposition surface size on the deposition velocity are analyzed. When the gravitational effect is dominant for a face-up surface or the attractive electrophoresis effect is dominant, the deposition velocity is estimated to be independent of the deposition surface size. Deposition under the influence of thermophoresis depends on the deposition surface size due to the formation of a thermal boundary layer. Deposition velocities for a 450-mm-long surface are studied under a temperature difference of 40 K and for electric field strengths ranging from 0 to 1000 V/cm.
Real-time detection of traffic events using smart cameras

With rapid increase of number of vehicles on roads it is necessary to maintain close monitoring of traffic. For this purpose many surveillance cameras are placed along roads and on crossroads, creating a huge communication load between the cameras and the monitoring center. Therefore, the data needs to be processed on site and transferred to the monitoring centers in form of metadata or as a set of selected images. For this purpose it is necessary to detect events of interest already on the camera side, which implies using smart cameras as visual sensors. In this paper we propose a method for tracking of vehicles and analysis of vehicle trajectories to detect different traffic events. Kalman filtering is used for tracking, combining foreground and optical flow measurements. Obtained vehicle trajectories are used to detect different traffic events. Every new trajectory is compared with collection of normal routes and clustered accordingly. If the observed trajectory differs from all normal routes more than a predefined threshold, it is marked as abnormal and the alarm is raised. The system was developed and tested on Texas Instruments OMAP platform. Testing was done on four different locations, two locations in the city and two locations on the open road.
Analyses of the structure of group correlations in Korean financial markets

In this paper, we construct and analyze the structure of cross-correlations in two Korean stock markets, the Korea Composite Stock Price Index (KOSPI) and the Korea Securities Dealers Automated Quotation (KOSDAQ). We investigate a remarkable agreement between the theoretical prediction and the empirical data concerning the density of eigenvalues in the KOSPI and the KOSDAQ. We estimate daily cross-correlations with respect to price fluctuations of 629 KOSPI and 650 KOSDAQ stock entities for the period from 2006 to 2010. The research for the structure of group correlations undress the market-wide effect by using the Markowitz multi-factor model and network-based approach. We find stock entities that involve the same business sectors and verify the structure of group correlations by applying a network-based approach. In particular, the KOSPI has a dense correlation besides overall group correlations for stock entities, whereas both correlations are less for the KOSDAQ than for the KOSPI.
Parameter Requirements for Noncooperative Satellite Maneuver Reconstruction Using Adaptive Filters

The Responsive Orbits division of the Center for Space Research and Assurance in the Aeronautics and Astronautics Department of the Air Force Institute of Technology investigates short-term tactical satellite missions that require frequent maneuvers. Pairing research in designing and conducting avoidance maneuvers with research in detecting and tracking maneuvering satellites sets the stage for developing and improving both areas. Strategies in stochastic filtering, smoothing, multiple model adaptive estimation, and maneuver reconstruction are developed to track a high-priority satellite. The article develops a wide range of simulations that modify the maneuver type, tracking antenna performance, antenna coverage, reconstruction method, filtering approach, and number of postmaneuver passes collected. The results determine the levels of error covariance necessary to perform successful maneuver reconstructions. Additionally, the results provide maneuver reconstruction confidence percentages based on the est.
Critical behaviors of mutual information in the one-dimensional spin-1 bilinear biquadratic model

The critical behaviors of the mutual information in the one-dimensional spin-1 bilinear biquadratic model are studied. It is found that all the quantum phase transition points including the order–disorder ones and the infinite-order ones in the system can be quantified from the singularity analysis of the mutual information of two sites with the longest distance, because the mutual information captures the correlation properties about the critical fluctuations. More interestingly, the special structure of the wavefunction and the special symmetric property of the system can be indicated by the entropy correlation behaviors. The finite size scaling laws of the mutual information and its derivative are also studied.