Miracle-dz/UniFAR-FTUs huggingface dataset:
Photoinduced volume change in arsenic chalcogenides by band-gap light

Photoinduced structural changes in molecular semicrystalline ${\mathrm{As}}_{4}{\mathrm{Se}}_{3}$ films have been characterized by extended x-ray absorption fine structure and x-ray diffraction under in situ band-gap laser illumination. Transient and permanent changes in the local and long-range structure have been determined quantitatively. In contrast to fully amorphous arsenic selenide films, a photoinduced contraction has been observed in semicrystalline ${\mathrm{As}}_{4}{\mathrm{Se}}_{3}$ films. A comprehensive phenomenological model is proposed for the photoinduced volume change in As-based chalcogenides. This model is based on two competing processes viz. intermolecular interaction through Coulombic repulsive force that results in photoexpansion, and cross-linking of molecular units through bond switching that causes photocontraction. A guideline is presented for selecting chalcogenide glass composition with specific photoinduced volume change characteristics.
Anomalous motion of membranes under a localized external potential

We investigate the relaxation and autocorrelation function of a particle attached to a membrane under the combined influence of an external potential and of the thermal undulations provided by the membrane. For a harmonic external potential the mean relaxation is given by the Mittag-Leffler decay function, while the autocorrelation, although closely related to the Mittag-Leffler behaviour, displays a more complex pattern. Relationship to experiments using optical tweezers is discussed.
ON THE INVERTIBILITY OF MULTIVARIATE LINEAR PROCESSES

It is shown that a multivariate linear stationary process whose coefficients are absolutely summable is invertible if and only if its spectral density is regular everywhere. This general characterization of invertibility is applied later to the case of a linear process having an autoregressive moving-average (ARMA) representation. Under the usual assumptions, it is deduced that a process Y described by an ARMA(φ, TH) model is invertible if and only if the polynomial detTH(z) has no roots on the unit circle. Given an invertible process Y which has an ARMA representation, it is finally shown that the process YT, where YT, =ei=0lSiYt-i, is invertible if and only if the matrix S(z) =ei=0lSizi is of full rank for all z of modulus 1. It follows, in particular, that any subprocess of an invertible ARMA process is also invertible.
A regional selectable distributed fibre-optic sensing system based on pulse correlation and partial reflectors

We have developed a regional selectable fibre-optic sensing system based on monitoring the length fluctuation of optic fibres by optical pulse correlation measurement. The multiple regional sensing fibres are cascadable and are connected by partial reflectors. The measurable regions are easily upgraded by a scanning of time position method. The results of strain experiments confirmed their linear response. These multiple region sensing techniques were experimentally operated within a resolution of less than 5 µε and over 4300 µε for sensing a region of 600 mm in length. A large number of sensing regions of in-line fibres can be exploited by the wide period, narrow width and high intensity of the pulse source and the high sensitivity of the optical signal detecting system.
Axial ratio reduced ultra wideband slot spiral on hybrid impedance surfaces

This paper presents a low-profile ultra wideband slot spiral antenna backed by a hybrid impedance surface. A unique aspect of the spiral is its hybrid impedance surface cavity leading to reduced axial ratio over a wide bandwidth. This is an improvement over conventional cavity-backed wideband spirals. Measurements demonstrated that the slot spiral on the proposed hybrid impedance surface achieved a 10:1 bandwidth from 0.6 to 6 GHz with an axial ratio of <4 dB. The cavity depth is only 13 mm, corresponding to 0. 03λ600 MHz at its lowest operational frequency. As such, this slot spiral is attractive in enabling low-profile ultra wideband antenna with excellent RF performance for conformal and wearable applications.
Algorithms and software for LMI problems in control

A number of important problems from system and control theory can be numerically solved by reformulating them as convex optimization problems with linear matrix inequality (LMI) constraints. While numerous articles have appeared cataloging applications of LMIs to control system analysis and design, there have been few publications in the control literature describing the numerical solution of these optimization problems. The purpose of this article is to provide an overview of the state of the art of numerical algorithms for LMI problems, and of the available software.
Room temperature continuous wave operation of a heterojunction bipolar transistor laser

Continuous wave laser operation at 25°C, with simultaneous electrical gain, of an InGaP–GaAs heterojunction bipolar transistor laser, with AlGaAs optical confining layers and an InGaAs recombination quantum well incorporated into the p-type base region, is demonstrated. At laser threshold (IB=40mA, VCB=0, 25°C), the transistor current gain β=ΔIC∕ΔIB in common-emitter operation changes abruptly (2.3→1.2,β>1), with laser modes developing at wavelength λ∼1006nm. Direct three-port modulation of the transistor laser at 3GHz is demonstrated for a device with a 2. 2μm emitter width and a 850μm length between cleaved Fabry–Perot facets (which is the performance of an exploratory device and not near the limits).
The erosion of a distributed two-dimensional vortex in a background straining flow

Herein we present a simplified theory for the behaviour of a vortex embedded in a growing external straining flow. Such a flow arises naturally as a vortex moves relative to other vortices. While the strain may generally exhibit a complex time dependence, the salient features of the vortex evolution can be understood in the simpler context, studied here, of a linearly growing strain. Then, all of the typical stages of evolution can be seen, from linear deformation, to the stripping or erosion of low-lying peripheral vorticity, and finally to the breaking or rapid elongation of the vortex into a thin filament. When, as is often the case in practice, the strain growth is slow, the vortex adjusts itself to be in approximate equilibrium with the background flow. Then, the vortex passes through, or near, a sequence of equilibrium states until, at a critical value of the strain, it suddenly breaks. In the intermediate period before breaking, the vortex continuously sheds peripheral vorticity, thereby steepening its edge gradients. This stripping is required to keep the vortex in a near equilibrium configuration. We show that this behaviour can be captured, quantitatively, by a reduced model, the elliptical model, which represents the vortex by a nested set of elliptical vorticity contours, each having a (slightly) different aspect ratio and orientation. Here, we have extended the original elliptical model by allowing for edge vorticity levels to be shed when appropriate (to represent stripping) and by incorporating the flow induced by the vorticity being stripped away. The success of this model proves that the essential characteristics of vortex erosion are captured simply by the leading-order, elliptical shape deformations of vorticity contours. Finally, we discuss the role of viscosity. Then, there is a competition between gradient steepening by stripping and smoothing by viscosity. If the strain grows too slowly, the vortex is dominated by viscous decay, and the edge gradients become very smooth. On the other hand, for sufficiently rapid strain growth (which can still be slow, depending on the viscosity), the vortex edge remains steep until the final breaking.
Yang-Mills theories in algebraic non-covariant gauges

This volume deals with canonical quantization, Feynman rules and renormalization of Yang-Mills theories in algebraic non-covariant gauges (typically axial and light-cone gauges). The material is self-contained and presented in a basic manner according to a personal style representative of a long lasting activity in the field. Emphasis is always placed on the underlying basic concepts of Quantum Field Theory, even when particular examples are treated, details and the related difficulties are thoroughly discussed. The value of the book goes beyond the specificity of its subject.
Search for coherent structure within tokamak plasma turbulence

Two‐dimensional tokamak edge density turbulence data are examined for possible coherent or organized structure. The spatial patterns of density fluctuations n appear to consist of localized ‘‘blobs’’ of relatively high or low density which can move irregularly both radially and poloidally through the edge region. However, a statistical analysis of the lifetime, area, direction, speed, and amplitude of these blobs does not as yet suggest any organized structure associated with the blobs beyond that which can be described by time‐averaged correlation functions.
The Radial Distribution of the Interstellar Medium in Disk Galaxies: Evidence for Secular Evolution

One possible way for spiral galaxies to internally evolve would be for gas to flow to the center and form stars in a central disk (pseudo-bulge). If the inflow rate is faster than the rate of star formation, a central concentration of gas will form. In this paper we present radial profiles of stellar and 8 μm emission from polycyclic aromatic hydrocarbons (PAHs) for 11 spiral galaxies to investigate whether the interstellar medium in these galaxies contains a central concentration above that expected from the exponential disk. In general, we find that the two-dimensional CO and PAH emission morphologies are similar, and that they exhibit similar radial profiles. We find that in 6 of the 11 galaxies there is a central excess in the 8 μm and CO emission above the inward extrapolation of an exponential disk. In particular, all four barred galaxies in the sample have strong central excesses in both 8 μm and CO emission. These correlations suggest that the excess seen in the CO profiles is, in general, not simply due to a radial increase in the CO emissivity. In the inner disk, the ratio of the stellar to the 8 μm radial surface brightness is similar for 9 of the 11 galaxies, suggesting a physical connection between the average stellar surface brightness and the average gas surface brightness at a given radius. We also find that the ratio of the CO to 8 μm PAH surface brightness is consistent over the sample, implying that the 8 μm PAH surface brightness can be used as an approximate tracer of the interstellar medium.
Turbulence profiling for long range surveillance imaging

We report a test of the turbulence found in real-world, horizontal imaging under high magnification. The experiment creates a double "star" on a test chart for use both with a SLODAR turbulence profiling instrument, and simultaneously imaged using a very fast camera to determine traditional seeing parameters. Effects on a similarly located image are investigated to determine the observed effects on the imagery as a function of turbulence location.
Origin and manipulation of the Rashba splitting in surface alloys

A novel method is demonstrated to tailor the electronic structure of high-Z surface alloys showing a giant Rashba splitting by means of electron doping. This aims for new model systems to study unconvential spin topologies and for possible applications in the field of spintronics. We give new insights into the origin of the enhanced Rashba effect in the two specific alloys Bi/Cu(111) and Bi/Ag(111) employing angle-resolved photoelectron spectroscopy and first-principles calculations.
Hawkes branching point processes without ancestors

In this article, we prove the existence of critical Hawkes point processes with a finite average intensity, under a heavy-tail condition for the fertility rate which is related to a long-range dependence property. Criticality means that the fertility rate integrates to 1, and corresponds to the usual critical branching process, and, in the context of Hawkes point processes with a finite average intensity, it is equivalent to the absence of ancestors. We also prove an ergodic decomposition result for stationary critical Hawkes point processes as a mixture of critical Hawkes point processes, and we give conditions for weak convergence to stationarity of critical Hawkes point processes.
Sensitivity of AIRS and IASI radiometric calibration to scene temperature

High radiometric accuracy under all conditions (such as scene temperature and scan angle) is critical for establishing a climate-quality data record. In this study we compare radiances of both AIRS and IASI using the difference each instrument sees between the brightness temperature at 1231 cm-1 and that at 961 cm-1. We collected spectra at 17 different sites distributed around the world in tropical, temperate, desert, and arctic climates. For perfectly calibrated instruments, the brightness temperature differences should closely agree, since diurnal differences caused by the differing orbits cancel to first order. We examine observed differences (indicative of calibration artifacts) as functions of scene temperature, time of day, and scan angle. AIRS is a cooled grating array spectrometer with 2378 spectral channels in the wavelength range from 3.7 to 15.4 microns. AIRS began routine operations in September 2002. IASI is a Fourier Transform spectrometer covering the range 3.6 to 15.5 microns in three bands. The spectral resolutions of AIRS and IASI are similar. IASI data have been available since July 2007.
Successful testing of the LISA Technology Package (LTP) interferometer engineering model

The LISA Technology Package (LTP), to be launched by ESA in 2008, is a technology demonstration mission in preparation for the LISA space-borne gravitational wave detector. A central part of the LTP is the optical metrology package (heterodyne interferometer with phasemeter) that measures the distance between two test masses with a noise level of 10 pm Hz−1/2 between 3 mHz and 30 mHz and also the test mass alignment with a noise level of <10 nrad Hz−1/2. An engineering model of the interferometer has been built and environmentally tested. Extensive functionality and performance tests were conducted. This paper reports on the successful test results.
Measuring an Effect Size From Dichotomized Data

It is well known that dichotomizing continuous data has the effect to decrease statistical power when the goal is to test for a statistical association between two variables. Modern researchers however are focusing not only on statistical significance but also on an estimation of the “effect size” (i.e., the strength of association between the variables) to judge whether a significant association is also clinically relevant. In this article, we are interested in the consequences of dichotomizing continuous data on the value of an effect size in some classical settings. It turns out that the conclusions will not be the same whether using a correlation or an odds ratio to summarize the strength of association between the variables: Whereas the value of a correlation is typically decreased by a factor π / 2 after each dichotomization, the value of an odds ratio is at the same time raised to the power 2 . From a descriptive statistical point of view, it is thus not clear whether dichotomizing continuous data leads to a decrease or to an increase in the effect size, as illustrated using a data set to investigate the relationship between motor and intellectual functions in children and adolescents.
Analysis of MAP , PH OA 2 / PH I 1 , PH O 2 / 1 retrial queue with vacation, feedback, two-way communication and impatient customers

This article concentrates on the steady-state analysis of a constant retrial queueing system with impatient customers, vacation, feedback, and two types of arrivals, namely the incoming calls which are made by the customers and the outgoing calls which are made by the server during the idle period. The incoming calls arrive at the system by following the Markovian Arrival Process(MAP) and service times of incoming/outgoing calls follow phase-type (PH) distribution, and the rest of the random variables are exponentially distributed. We have framed our model for analyzing some of the basic situations/problems in telecommunication systems. With the support of matrix analytic method, the invariant analysis of our system has been carried out. We have also discussed the busy period and have performed the cost analysis for our model. At last, we have validated our model through numerical and graphical exempliﬁcations.
THERMO-CHEMO-MECHANICAL MODEL FOR CONCRETE. II: DAMAGE AND CREEP

In this work a coupled thermo-chemo-mechanical model for the behavior of concrete at early ages is proposed. This paper presents the formulation and assessment of the mechanical aspects of the model. Short- and long-term mechanical behaviors are modeled via a viscoelastic damage model that accounts for the aging effects. The short-term model is based on the framework of the continuum damage mechanics theory. A novel normalized format of the damage model is proposed, so that the phenomenon of aging is accounted for in a natural fashion. Long-term effects are included by incorporating a creep model inspired in the microprestress-solidification theory.
InGaAsP/InP laser diodes/superluminescent diodes with nonidentical quantum wells

Novel behavior of laser diodes (LDs) and superluminescent diodes (SLDs) fabricated on substrates with nonidentical quantum wells has been discovered. Mirror-imaged nonidentical quantum well (QW) lasers/superluminescent diodes have been designed, fabricated, and measured. Nonuniform carrier distribution inside multiple quantum wells is further verified experimentally. Measured characteristics also show that electrons, instead of holes, are the dominant carrier affecting carrier distribution. The sequence of the nonidentical QW is also shown to have significant influence on device characteristics, showing very different carrier distribution in each sequence.
A note on tests of significance in multivariate analysis

Multivariate generalizations. In multivariate statistical analysis, common terms such as variances and correlation coefficients have received certain generalizations. Wilks (7) has called the determinant |V|, where V is the matrix of variances and covariances between several variates, a generalized variance; certain ratios of such determinants have been called by Hotelling(5) vector correlation coefficients and vector alienation coefficients. While these determinantal functions have properties which justify to some extent this kind of generalization, it sometimes seems more reasonable to leave any generalized parameters, or corresponding sample statistics, in the form of matrices of elementary quantities. This is stressed by the formal analogy which then often exists between the generalized and the elementary formulae.
Wavelet Analysis of Cirrus Multiscale Structures from Lidar Backscattering : A Cirrus Uncinus Complex Case Study

Abstract Although cirrus cloud structures play an important role in dynamics issues, cloud radiative calculations, and cloud parameter retrievals from satellite measurements, fully understanding cirrus cloud structures still remains a challenge. A case study of a cirrus containing mesoscale uncinus complexes (MUC) with a two-layer structure observed by a high-resolution lidar is presented using the method based on wavelet transform. The results indicate that dynamical processes play a leading role in determining cloud multiscale structures. The uncinus cells with a length scale on the order of ∼1 km, embedded in both the top and lower layers, have similar spectral features and are probably produced by a similar mechanism—thermal perturbation generated by heating and cooling effects associated with phase changes of water (i.e., adiabatic heating) and radiative processes. However, the mesoscale cloud patches are probably involved in different dynamics processes, suggesting that understanding of the interact.
Finite-size corrections to the chemical potential

The particle-insertion method of Widom (1963) has been widely used in numerical simulations for the purpose of calculating the excess chemical potential, mu ex. It is known, however, that values of mu ex obtained by Widom's method are strongly dependent on N, the number of particles in the system. The authors use the formalism of the grand-canonical ensemble to derive an expression for the leading term in the finite-size correction to mu ex. The new expression reduces to the exact result for hard rods and gives numerical results in good agreement with those of simulations of hard-disk and hard-sphere fluids. It is, in both respects, an improvement over an expression previously derived by Smit and Frenkel via a thermodynamic argument.
Waves and Mean Flows

Preface Part I. Fluid Dynamics and Waves: 1. Elements of fluid dynamics 2. Linear waves 3. Geometric wave theory 4. Dispersive waves and ray tracing Part II. Wave-Mean Interaction Theory: 5. Zonally symmetric wave-mean interaction theory 6. Internal gravity waves 7. Shear flows 8. Three-dimensional rotating flow 9. Rossby waves and balanced dynamics 10. Lagrangian-mean theory 11. Zonally symmetric GLM theory Part III. Waves and Vortices: 12. A framework for local interactions 13. Wave-driven vortex dynamics on beaches 14. Wave refraction by vortices Bibliography Index.
The far-infrared morphology of the double-ringed galaxy NGC 4736 (M94) - A ring surrounding an extended nucleus

High spatial resolution 100-micron observations of the central region of the double-ringed spiral galaxy NGC 4736 (M94) were obtained using the Kuiper Airborne Observatory. The data show a strong central peak with secondary peaks at the radius of the inner ring (50 arcsec = 1.6 kpc). The nuclear emission is extended at 100 microns, with a radius of 15 arcsec (500 pc). The far-infrared morphology is similar to that of the molecular gas, while the H I distribution shows a pronounced central depression. Since most of the hydrogen gas in the inner regions of NGC 4736 is in molecular form, it is concluded that the far-infrared emission from NGC 4736 arises mainly from dust associated with molecular gas. The H-alpha distribution differs dramatically from the far-infrared and molecular gas distributions. The ring dominates the H-alpha emission, while the total 100-micron ring emission is only slightly larger than that of the nucleus, yielding an L(FIR)/L(H-alpha) for the nucleus about 100 times that of the ring. The bolometric luminosity of the stars in the inner 1 kpc of NGC 4736 is sufficient to power the far-infrared from this region, which suggests that a significant fraction of the far-infrared emission in the nuclearmore » region of NGC 4736 is powered by non-OB stars rather than by star formation. 61 refs.« less
Simulation of two-photon photoemission from the bulk sp -bands of Ag(111)

Theoretical and experimental studies on the two-photon photoemission excited by femtosecond laser pulses from the $sp$-band of Ag(111) in normal direction are reported. At low temperatures, the two-photon photoemission spectrum is found to consist mainly of nonresonant direct transitions from the lower to the upper $sp$-band across the $L$-projected band gap involving the upper $sp$-band as virtual intermediate states. This direct photoemission signal is calculated from the Ag band structure using optical Bloch equations and dipole moments derived from the nearly free electron approximation. For finite temperatures, a minor additional temperature-dependent, continuous contribution to the two-photon photoemission spectrum is experimentally determined. This background due to the secondary electrons is theoretically modeled combining the Debye model and Fermi Liquid Theory to account for electron relaxation effects during the two-photon photoemission process.