Miracle-dz/UniFAR-FTUs huggingface dataset:
Femtosecond x-ray pulse length characterization at the Linac Coherent Light Source free-electron laser

Two-color, single-shot time-of-flight electron spectroscopy of atomic neon was employed at the Linac Coherent Light Source (LCLS) to measure laser-assisted Auger decay in the x-ray regime. This x-ray-optical cross-correlation technique provides a straightforward, non-invasive and on-line means of determining the duration of femtosecond (>40 fs) x-ray pulses. In combination with a theoretical model of the process based on the soft-photon approximation, we were able to obtain the LCLS pulse duration and to extract a mean value of the temporal jitter between the optical pulses from a synchronized Ti-sapphire laser and x-ray pulses from the LCLS. We find that the experimentally determined values are systematically smaller than the length of the electron bunches. Nominal electron pulse durations of 175 and 75 fs, as provided by the LCLS control system, yield x-ray pulse shapes of 120±20 fs full-width at half-maximum (FWHM) and an upper limit of 40±20 fs FWHM, respectively. Simulations of the free-electron laser agree well with the experimental results.
Photonic generation of ultra-wideband monocycle and doublet pulses using simplex semiconductor optical amplifier

We demonstrate two all-optical methods for UWB pulse generation based on various nonlinearities of the semiconductor optical amplifier (SOA), namely, self phase modulation (SPM), and cross gain modulation (XGM). In the first method, we present UWB doublet generation based on SPM. The monocycle pulse is generated from dark return-to-zero (RZ) signal, and then converted to doublet pulse by injecting an additional probe signal with the SMF transmission. For the first time to best of our knowledge, we report that the generated doublet pulses are transmitted over 5km SMF by proper dispersion compensation without distortion. Second, we present UWB doublet generation by XGM of two cascaded SOAs. The configuration of our all-optical methods is compact and simple.
An improved version of the NEH algorithm and its application to large-scale flow-shop scheduling problems

This paper deals with the Flow-shop Scheduling Problem (FSP). The NEH algorithm is regarded as one of the best constructive methods for solving the FSP. However, the running time of the NEH algorithm when used to solve large-scale FSPs is fairly long. The block properties of the FSP are investigated to reduce the running time. Using these block properties it is found that if a partial schedule is evaluated, the lower bounds of other partial makespans can be obtained in a time of O(1). A pruning procedure based on the block properties of the FSP is introduced into the NEH algorithm to reduce the computational complexity. Experimental results show that the improved NEH algorithm has a greatly reduced running time compared with the classical NEH algorithm. It takes less than 0.2 seconds on average to get a solution for a large-scale FSP (up to 500 jobs and 20 machines).
Excitons and multi-excitons in heterostructures semiconductor nanocrystals

Multiple excitations in quantum dots core/shell heterostructures are studied via quasi continuous wave multiexciton spectroscopy method. For ZnTe/CdSe core/shell quantum dots, a transfer from attractive to repulsive biexciton binding energy is detected as the shell thickness increases, indicating a transfer from quasi type-I to type-II regimes. For CdSe/CdS seeded nanorods, a transfer from binding to repulsive behavior is detected for the biexciton, accompanied by significant reduction in oscillator strength of the triexciton transition as core diameters decreases below 2.8nm, indicating a transition of the electronic excited states from type-I localization in the core to a quasi type-II delocalization along the entire rod as the core diameter decreases. However, as rods dimensions are decreased, a transfer from repulsive to binding biexciton energy occurs, demonstrating a change of the system from a quasi type-II to quasi-type-I behavior.
Nonlinear optical scattering: The concept of effective susceptibility

We present a general theoretical method for deriving effective susceptibilities for (non)linear optical scattering processes of arbitrary order using the reciprocity principle. This method allows us to formulate a generalized treatment of nonlinear optical scattering and deduce selection rules independent of the precise mechanism of light-matter interaction. We particularize this approach to second-order sum frequency scattering from an inhomogeneous medium and consider the limiting cases of small particle scattering, refractive index matched (Rayleigh-Gans-Debye) scattering, small refractive index contrast (Wentzel-Kramers-Brillouin) scattering and correlated scattering. We compare the derived expressions to experimental results of sum frequency scattering from monodisperse particles in suspension with varying sizes.
Quantum Monte Carlo methods

Simulations of complex systems have seen rapid progress over the last decade not only due to the continuous acceleration of computer resources but also due to improvements of methods and algorithms. Simulations complement experiments and model calculations in the effort to get insight into complex systems such as materials, complex liquids, or complicated molecules. As such, computer simulations are a strongly interdisciplinary field where chemistry meets physics, biology, and material science. Most simulations are based on classical physics because the interaction between atoms or even larger entities can be modeled accurately with classical mechanics for most problems as long as no chemical reactions are involved. If the interaction between atoms in a molecule or between molecules is to be calculated, for instance, to obtain parameters for modeling the interactions in classical simulations, classical physics has to be abandoned because these interactions involve the electron distributions which require a quantum mechanical description. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 388–402 DOI: 10.1002/wcms.40
Electromigration Behavior of Eutectic SnPb Solder

Electromigration characteristics of eutectic SnPb solder were studied using thin stripe-type test structures. Significant changes in the microstructure were observed after the electromigration test, in which the temperature and the current density were varied from 80 to 100°C and from 4.6 to 8.7×104 A/cm2, respectively. While voids or local thinning were found near the cathode end, hillocks were mainly observed near the anode end. From resistance measurements, it was calculated that the activation energy of the eutectic SnPb solder for electromigration was 0.77 eV. The dominant migrating element along the electron flow at 100°C was Pb.
Multiple-Object Space Surveillance Tracking Using Finite-Set Statistics

The dynamic tracking of objects is, in general, concerned with state estimation using imperfect data. Multiple object tracking adds the difficulty of encountering unknown associations between the collected data and the objects. State estimation of objects necessitates the prediction of uncertainty through nonlinear (in the general case) dynamical systems and the processing of nonlinear (in the general case) measurement data in order to provide corrections that refine the system uncertainty, where the uncertainty may be non-Gaussian in nature. The sensors, which provide the measurement data, are imperfect with possible misdetections, false alarms, and noise-affected data. The resulting measurements are inherently unassociated upon reception. In this paper, a Bayesian method for tracking an arbitrary, but known, number of objects is developed. The method is based on finite-set statistics coupled with finite mixture model representations of the multiobject probability density function. Instead of relying on .
Multiband–multislot planar antenna based on small loop-radiator

In this article, a novel multiband–multislot planar antenna is presented. The proposed antenna is based on the small loop- and slot radiators, showing multiple resonances. The antenna is built on a substrate with a permittivity of 2.2 and a thickness of 1.27 mm. The antenna resonates at 0.84, 1.55, 2.5 and 4.8 GHz behaving with quasi-omnidirectional radiation patterns, which can be employed in the state of the art automotive technology, laptops and tablets among other terminal devices. The resonances can be shifted to lower or higher frequencies depending on the slots’ length and width, as well as the magnetic coupling among them. Moreover, additional resonances can be introduced by etching new slots on the substrate metallization.
Estimation of the Intraclass Correlation Coefficient for the Analysis of Covariance Model

Abstract For the unbalanced analysis of covariance model with one covariate, a simple formula is given for the intraclass correlation coefficient estimator that results from Henderson's Method 3 estimation of variance components. Example calculations and the corresponding interpretations are given for a study of the correlation of iron content among brothers. The example illustrates the manner in which the estimator depends on the pattern of correlation between the covariate and the variable under investigation.
Numerical investigation on the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence

Direct Numerical Simulations of the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence are presented in this paper. The jet's structure, surface behavior, non-Newtonian characteristics as well as its specific breakup mechanism are investigated and discussed. The shear thinning viscosity of the liquid phase plays an important role during jet injection resulting in circumferential rotation of interfacial waves. Streamwise contra-rotating vortex pairs as well as triple vortex structures are observed in the liquid phase. The local Ohnesorge number, which has a branch-structure distribution in the liquid phase before disintegration, is found to be 30% smaller in regions near the nozzle exit and in the shear layer than in the jet tip, suggesting a clear non-Newtonian influence. A cavity breakup mechanism for this type of non-Newtonian jet is identified and explained, giving a new perspective for jet disintegration analysis.
A direct approach to the exit problem

This paper considers the problem of exit for a dynamical system driven by small white noise, from the domain of attraction of a stable state. A direct singular perturbation analysis of the forward equation is presented, based on Kramers’ approach, in which the solution to the stationary Fokker–Planck equation is constructed, for a process with absorption at the boundary and a source at the attractor. In this formulation the boundary and matching conditions fully determine the uniform expansion of the solution, without resorting to “external” selection criteria for the expansion coefficients, such as variational principles or the Lagrange identity, as in our previous theory. The exit density and the mean first passage time to the boundary are calculated from the solution of the stationary Fokker–Planck equation as the probability current density and as the inverse of the total flux on the boundary, respectively. As an application, a uniform expansion is constructed for the escape rate in Kramers’ problem o.
High power terahertz quantum cascade laser

We present high power terahertz quantum laser at about 3 THz based on bound-to-continuum active region design. At 10 K, corrected by the collection efficiency, the maximum peak power of 137 mW is obtained in pulsed mode. What’s more, we firstly introduce monolithically integrated THz quantum cascade laser (QCL) array and the maximum peak power increased to 218 mW after correction. In total, the array shows better performance than single device, implying cheerful prospect.
Discontinuous Galerkin FEM in Computer Graphics

The ﬁnite element method (FEM) is the method of choice for computing the numerical solution to many problems that can be formulated as partial differential equations (PDEs) on irregular domains. Today, it is used in almost every ﬁeld of engineering and was also quickly adopted by computer graphics research where it is now heavily used in the areas of physically-based simulation and geometric modeling. In contrast to standard FEM, which we also refer to as continuous Galerkin FEM (CG FEM), discontinuous Galerkin FEM (DG FEM) allows its basis functions to be discontinuous across elements. The lost coupling between elements is then restored by introducing penalty terms that act to reduce these discontinuities. Just like CG FEM, DG FEM has a solid mathematical foundation and can be shown to converge to the exact solution under certain conditions. The reduced continuity requirements of DG FEM result in several advantages, which this thesis aims to exploit in the context of computer graphics: elements can have arbitrary shapes; the creation of a valid element mesh as well as the modiﬁcation of the mesh over time are simpliﬁed; each element is endowed with its own set of basis functions, and the quality of the approximation to the exact solution can be chosen on a per-element basis. The work presented here applies DG FEM in the context of physically-based simulation of deformable solids and shells, as well as image warping. The method is applied to linear as well as non-linear problems, deﬁned through second and fourth order elliptic PDEs in two and three spatial dimensions. In each of these applications, different aspects of DG FEM are at the focus of attention. For the simulation of deformable solids, the arbitrary element shapes allow for topological changes without further element remeshing. Combined with an exact integration scheme and corotated elasticity, this enables applications such as the efﬁcient simulation of progressive cutting, dynamic mesh reﬁnement, and a novel mesh generation approach. In the context of shell simulations, a DG method for the Kirchhoff-Love shell equations is merged with the extended FEM (XFEM) to come up with a novel method for the simulation of highly detailed cutting and fracturing
Central Star Temperatures of Low-Excitation Planetary Nebulae

New Zanstra temperatures of the central stars or low-excitation PNe and Kaler's (1987) Stoy method for determining the T(e)s of such stars are correlated here with the intensity of forbidden O III 5007 A for young PNE with no or weak He II 4686 A. Recent energy balance temperatures are shown to be unsatisfactory for this class of objects. Comparisons among the temperatures in cases were He II is detected show that PNe may start becoming optically thin for central star temperatures in the 40,000-50,000 K range and that the Zanstra discrepancy for this class of objects may be resolved by invoking low optical depth. The Stoy calibration seems to give the best estimate of central star temperatures from the 5007 A line. The correlations are valuable for determining effective temperatures in cases where no nuclei can be detected and are especially useful for extragalactic objects. 50 refs.
Review of micro-autonomous vehicle sizing and power modeling

This paper presents a discussion on sizing, weight and power of micro autonomous air and ground vehicles. While the air vehicles include both rotor and flapper based design, here the focus is on rotor based designs. The paper presents modeling methodologies for initial sizing of these vehicles and a survey of small COTS batteries. Some results from initial iterations on sizing vehicles and payloads are also presented. For air-vehicles, several factors have been identified in the sizing process, which can be adjusted in the search for a feasible design. These factors include the rotor figure of merit, the motor efficiency, and the battery specific energy. For ground vehicles, due to limited experimental data, three different ways for preliminary estimation of power requirements as a function of vehicle mass have been explored here. The sizing methodologies marry theoretical foundations with empirical observations and estimations.
Pattern recognition and subjective belief learning in repeated mixed strategy games

This paper aspires to fill a conspicuous gap in the existing literature on learning in games, namely the absence of any empirical verification of learning rules involving pattern recognition. An extension of weighted fictitious play is proposed both obeying cognitive laws of subjective perception, and allowing for two-period pattern detection of opponents' behavior. The unconditional prior probability of a subject employing a pattern detecting belief model is 0.34, as estimated by a mixture (latent-class) model of the elicited belief and action data series from Nyarko and Schotter (2002), or 0.551 using only action data. The conditional prior probability of using pattern recognition was found to depend positively on a measure of the exploitable two-period patterns in an opponent's action choices, in stark contrast to the minimax hypothesis. Also, standard weighted fictitious play models are found to significantly bias memory parameter estimates upwards, compared to the proposed subjective fictitious play models. Finally, simulations of learning models reveal that the simple win-stay/lose-shift heuristic may be effective even against more complex pattern detecting models.
Internal Entropy Production in Magnetic Systems

Abstract In the framework of the mathematically and conceptually simple two-level mean-field model of an electronic spin system characterised by the spin-lattice relaxation time, actual magnetic phenomena have been evaluated within the language of irreversible thermodynamics, namely in terms of internal entropy production. A suitable description of both reversible and irreversible magnetization processes is presented which enables one to distinguish between them. It is suggested that, on the basis of this model, the majority of the phenomena observed in magnetic systems, for example, the construction of hysteresis loops, the energy balance of magnetization processes, the Steinmetz rule, etc., should be experimentally evaluated.
Abnormal grain growth in aluminum alloy thin films

Abnormal grain growth in 0.75‐μm‐thick aluminum alloy thin films has been studied using x‐ray diffractometry, plan‐view and cross‐sectional transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive x‐ray analysis. Transmission electron microscopy was used with preannealed samples as well as with samples annealed in situ. By varying the deposition temperatures, compositions, and annealing conditions, we have determined the roles of alloying elements in the formation of second‐phase precipitates and in promoting abnormal grain growth.
Erratum: “Hubble Space Telescope Observations of 10 Two-Image Gravitational Lenses” (ApJ, 536, 584 [2002])

Notes. —The coordinate origin is the ‘‘ A ’’ image of the lens. The standard catalog of objects extends to a radius of 2000 from the lens, with objects labeled G# for galaxies and S# for stellar objects, respectively. Galaxies outside the 2000 radius which could produce a tidal shears exceeding 1% are labeled by T#, Objects labeled H# were detected only in the infrared. Tidal shear estimates are scaled to the lens galaxy magnitude in the corresponding filter, after correcting for the SExtractor magnitude offset discussed in x 2. The Astrophysical Journal, 571:1021, 2002 June 1
Adhesion enhancement by a dielectric barrier discharge of PDMS used for flexible and stretchable electronics

Currently, there is a strong tendency to replace rigid electronic assemblies by mechanically flexible and stretchable equivalents. This emerging technology can be applied for biomedical electronics, such as implantable devices and electronics on skin. In the first step of the production process of stretchable electronics, electronic interconnections and components are encapsulated into a thin layer of polydimethylsiloxane (PDMS). Afterwards, the electronic structures are completely embedded by placing another PDMS layer on top. It is very important that the metals inside the electronic circuit do not leak out in order to obtain a highly biocompatible system. Therefore, an excellent adhesion between the 2 PDMS layers is of great importance. However, PDMS has a very low surface energy, resulting in poor adhesion properties. Therefore, in this paper, PDMS films are plasma treated with a dielectric barrier discharge (DBD) operating in air at medium pressure (5.0 kPa). Contact angle and XPS measurements reveal that plasma treatment increases the hydrophilicity of the PDMS films due to the incorporation of silanol groups at the expense of methyl groups. T-peel tests show that plasma treatment rapidly imparts adhesion enhancement, but only when both PDMS layers are plasma treated. Results also reveal that it is very important to bond the plasma-treated PDMS films immediately after treatment. In this case, an excellent adhesion is maintained several days after treatment. The ageing behaviour of the plasma-treated PDMS films is also studied in detail: contact angle measurements show that the contact angle increases during storage in air and angle-resolved XPS reveals that this hydrophobic recovery is due to the migration of low molar mass PDMS species to the surface.
A saturated discrete particle model and characteristic‐based SPH method in granular materials

Based on the discrete particle model for solid‐phase deformation of granular materials consisting of dry particulate assemblages, a discrete particle–continuum model for modelling the coupled hydro‐mechanical behaviour in saturated granular materials is developed. The motion of the interstitial fluid is described by two parallel continuum schemes governed by the averaged incompressible N–S equations and Darcy's law, respectively, where the latter one can be regarded as a degraded case of the former.
Symmetric Location Estimation/Testing by Empirical Likelihood

Abstract The problem of estimating the center of a symmetric distribution is well studied and many nonparametric procedures are available. It often serves as the test problem for many nonparametric estimation procedures, and stimulated the development of efficient nonparametric estimation theory. We use this familiar setting to illustrate a novel use of empirical likelihood method for estimation and testing. Empirical likelihood is a general nonparametric inference method, see Owen [Owen, A. (2001). Empirical Likelihood. London: Chapman and Hall]. However, for symmetric location problem (and some other problems) empirical likelihood has difficulties. Owen (2001) call them “challenges for the empirical likelihood”. We propose and study a way to use the empirical likelihood with such problems by modifying the parameter space. We illustrate this approach by applying it to the symmetric location problem. We show that the usual asymptotic theory of empirical likelihood still holds and the asymptotic efficiency of the so obtained empirical NPMLE of location is studied.
Generating Particle Beams of Controlled Dimensions and Divergence: I. Theory of Particle Motion in Aerodynamic Lenses and Nozzle Expansions

A particle beam is produced when a particle-laden gas expands through a nozzle into a vacuum. This work discusses the theoretical basis of a novel method for producing highly collimated and tightly focused particle beams. The approach is to pass the particle-laden gas through a series of axisymmetric contractions and enlargements (so-called aerodynamic lenses) before the nozzle expansion. Particles are moved closer to the axis by a lens if the particle sizes are less than a critical value and particles can be confined very closely to the axis by using multiple lenses in series. Since particles close to the axis experience small radial drag forces, they stay close to the axis during nozzle expansion and therefore form a narrow particle beam downstream. The major effects that limit the minimum beam width are Brownian motion and lift forces on particles during the nozzle expansion. Simple theoretical models are developed in this work to estimate the minimum particle beam width set by these effects. While the.