Miracle-dz/UniFAR-FTUs huggingface dataset:
High-Energy-Density Laboratory Astrophysics Studies of Jets and Bow Shocks

We present the first results from high-energy-density laboratory astrophysics experiments that explore the interaction of supersonic jets/outflows with an ambient medium. Our experiments were conducted on the Omega laser facility, a large Inertial Confinement Fusion facility. In our experiments, a laser pulse drives a supersonic jet into foam. High-resolution X-ray radiography reveals the resulting highly structured bow shock. These are the first laboratory astrophysics experiments to capture the behavior of both the jet and the bow shock. We discuss the astrophysical relevance of the flow processes that we observe in the experiments and in the accompanying numerical models. Scaling arguments suggest that our experiments are most directly relevant to active galactic nucleus jets and planetary nebula outflows, while future work may allow our experiments to extend into regimes relevant to radiative outflows from young stellar objects.
Plasma decay in N2, CO2 and H2O excited by high-voltage nanosecond discharge

Plasma decay after a high-voltage nanosecond discharge was studied experimentally and numerically in room temperature N2, CO2 and H2O for pressures between 1 and 10 Torr. The time-resolved electron density was measured by a microwave interferometer for initial electron densities in the range 8 × 1011–3 × 1012 cm−3 and the effective electron–ion recombination coefficient was determined. It was shown that this coefficient varies in time and depends on pressure. A numerical simulation was carried out to describe the temporal evolution of the densities of charged particles under the conditions considered. A good agreement was obtained between the calculated and the measured electron density histories. It was shown that the loss of electrons is governed by dissociative recombination with complex ions, their density being dependent on pressure. In N2 at low pressures, a hindered electron thermalization in collisions with molecules led to a delay in the plasma decay. This effect was observed both experimentally and theoretically.
TiO2 nanotubes as a cold cathode for x-ray generation

Here we report on an x-ray source based on titanium dioxide (TiO2) nanotubes grown by electrochemical oxidation. From the analysis of current-voltage characteristics of TiO2 electron emitter field emission nature of the current was confirmed. The threshold voltage and field enhancement factors were derived to be ∼1.8 V/μm and ∼8363, respectively. The current density was ∼4.0 mA/cm2 at ∼2.4 V/μm. The stability tests showed that the current stayed stable within 6% for more than 720 h. TiO2 nanotubes were used as a cold cathode in x-ray tube and it was demonstrated that TiO2 nanotubes could be a good candidate for such applications.
Generation of ferroelectric domains in atomic force microscope

A theory of an equilibrium shape of domains formed in an electric field of atomic force microscope (AFM) is proposed. The domain shape depends on parameters of the ferroelectric and on the applied voltage. Under low voltages the length and the diameter of the domain are of the same order of magnitude. With voltage increase the ratio between the length and the diameter increases. A correlation between the lateral sizes and the spontaneous polarization value is considered. It is shown that under the same voltage the thinnest domains are formed in ferroelectrics with high spontaneous polarization. The concept of the domain shape invariant as a combination of the domain length and lateral size, which is constant when changing the AFM parameters, is introduced. Results of the calculation of the invariant value in barium titanate as well as of the domain dimensions and the shape in GASH are in good agreement with the experiment.
Effective charge of low-velocity ions in matter: A comparison of theoretical predictions with data derived from energy-loss measurements

Effective charge fractions zeta/sub expt/ = Z/sub 1//sup -1/ (S/S/sub p/)/sup 1/2/, of low-velocity ions with atomic number Z/sub 1/ are extracted from high-precision measurements of stopping powers S for He, N, Ne, and Ar ions in C, Al, and Au for the ion velocity range 0.47< or =v/sub 1//v/sub 0/< or =1.28. Proton stopping powers S/sub p/ were taken from literature data. The experimental effective charge fractions zeta/sub expt/ are compared with calculated values zeta/sub theor/ as derived in linear-response theory on the basis of a statistical model of ions of given degree of ionization q. At low ion velocities, zeta/q is predicted to be significantly larger than 1, and to approach 1 with increasing Z/sub 1/, v/sub 1/, or r/sub s/. The experiments confirm these trends. The observed Z/sub 1/ dependence of zeta/sub expt/ is somewhat more pronounced than expected by the linear-response approximation.
Phenomenology of electron-beam-induced photoresist shrinkage trends

For many years, lithographic resolution has been the main obstacle in keeping the pace of transistor densification to meet Moore's Law. For the 45 nm node and beyond, new lithography techniques are being considered, including immersion ArF (iArF) lithography and extreme ultraviolet lithography (EUVL). As in the past, these techniques will use new types of photoresists with the capability to print 45 nm node (and beyond) feature widths and pitches. In a previous paper [1], we focused on ArF and iArF photoresist shrinkage. We evaluated the magnitude of shrinkage for both R&D and mature resists as a function of chemical formulation, lithographic sensitivity, scanning electron microscope (SEM) beam condition, and feature size. Shrinkage results were determined by the well accepted methodology described in ISMI's CD-SEM Unified Specification [2]. A model for resist shrinkage, while derived elsewhere [3], was presented, that can be used to curve-fit to the shrinkage data resulting from multiple repeated measurements of resist features. Parameters in the curve-fit allow for metrics quantifying total shrinkage, shrinkage rate, and initial critical dimension (CD) from before e-beam exposure. The ability to know this original CD is the most desirable result; in this work, the ability to use extrapolation to solve for a given original CD value was also experimentally validated by CD-atomic force microscope (AFM) reference metrology. Historically, many different conflicting shrinkage results have been obtained among the many works generated through the litho-metrology community. This work, backed up by an exhaustive dataset, will present an explanation that makes sense of these apparent discrepancies. Past models for resist shrinkage inherently assumed that the photoresist line is wider than the region of the photoresist to be shrunk [3], or, in other words, the e-beam never penetrates enough to reach all material in the interior of a feature; consequently, not all photoresist is affected by the shrinkage process. In actuality, there are two shrinkage regimes, which are dependent on resist feature CD or thickness. Past shrinkage models are true for larger features. However, our results show that when linewidth becomes less than the eventual penetration depth of the e-beam after full shrinkage, the apparent shrinkage magnitude decreases while shrinkage speed accelerates. Thus, for small features, most shrinkage occurs within the first measurement. This is crucial when considering the small features to be fabricated by immersion lithography. In this work, the results from the previous paper [1] will be shown to be consistent with numerically simulated results, thus lending credibility to the postulations in [1]. With these findings, we can conclude with observations about the readiness of SEM metrology for the challenges of both dry and immersion ArF lithographies as well as estimate the errors involved in calculating the original CD from the shrinkage trend.
Double tearing mode induced by parallel electron viscosity in tokamak plasmas

The linear behaviors of the double tearing mode (DTM) mediated by parallel electron viscosity in cylindrical plasmas with reversed magnetic shear and thus two resonant rational flux surfaces is numerically investigated. The distance between the two surfaces is found to play an important role for modes with poloidal mode number m>1. Two modes, one of which is centered at the inner rational surface and the other is located between the two surfaces, are simultaneously unstable and the growth rates show the standard single tearing mode (STM) scaling as γ∝R−1/3 when the distance is large (here, the Reynolds number R≡τυ/τh, τυ, and τh are, respectively, the viscosity penetration time of the magnetic field and the Alfven time for a plasma sheet of width a). The latter is unstable only and the growth rate transits to the standard DTM scaling as γ∝R−1/5 for low-m (e.g., m<4) modes and keeps the STM scaling γ∝R−1/3 for high-m (e.g., m∼10) modes, which are found dominant, when the distance is decreased. In contrast,.
Stability aspects of a family of anisotropic models of elliptical galaxies

Phase space properties of elliptical galaxies suggested by numerical experiments on dissipationless galaxy formation were used previously as a dynamical constraint in the construction of self-consistent equilibrium models. These quasi-spherical models naturally lead to the R exp 1.4 luminosity law if M/L is assumed to be approximately constant. In this paper, several aspects of the stability of this approach are tested. The overall dynamical stability of the f(infinity) models is confirmed by N-body simulations. Dynamical instability is found only in a region of parameter space where the models display unrealistic properties. The results support the view that the mass distribution in ellipticals, and thus the luminosity law for a constant M/L, is directly related to the properties at large radii of the mass density and pressure anisotropy that are consistent with the picture of galaxy formation via dissipationless collapse. 30 references.
Infrared dielectric anisotropy and phonon modes of sapphire

Spectroscopic ellipsometry in the infrared spectral range is used for comprehensive analysis of the anisotropic dielectric response of sapphire. We determine the ordinary and extraordinary infrared complex dielectric functions as well as all infrared-active phonon modes of single crystal $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ for wavelengths from 3 to 30 \ensuremath{\mu}m. Data were acquired from high-symmetry orientations of a-plane and c-plane surfaces cut from bulk crystals. A simple classification scheme is developed, which allows identification of the total reflection bands for p- and s-polarized light in anisotropic materials with multiple phonon branches. We employ a factorized form of the dielectric function for superior best-fit calculation of the infrared ellipsometry spectra adjusting frequencies and damping parameters of the transverse and longitudinal phonon modes with ${A}_{2u}$ and ${E}_{u}$ symmetry separately. A generalized Lowndes condition for the damping parameters is derived and found satisfied for the ${A}_{2u}$ and ${E}_{u}$ branches. Excellent agreement with phonon mode literature values is obtained, and improper use of selection rules reported previously for calculation of the sapphire dielectric functions is revised [Harman, Ninomiya, and Adachi, J. Appl. Phys. 76, 8032 (1994)]. The dielectric function model will become useful for infrared ellipsometry investigation of multiple-layer structures grown on $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ substrates such as group-III nitride heterostructures.
The intensification and shift of the annual North Atlantic Oscillation in a global warming scenario simulation

The impact of global warming on the annual North Atlantic Oscillation (NAO) is investigated with a global warming scenario simulation of the ECHAM4/OPYC3 coupled general circulation model. It is shown that the annual meridional pressure gradient over the North Atlantic is significantly strengthened, and the two centers of action of the NAO, the Icelandic low and the Azores high, are intensified and shifted northeastward by 10° to 20° in latitude and 30° to 40° in longitude in the global warming scenario. The shift of the centers of action leads to a failure in capturing the NAO change with the traditional definition of the NAO index. A modified index is introduced that allows for this shift, and exhibits a tendency toward the positive phase and an enhancement of its intensity. The intensification of Icelandic low is tied up with zonal mean state change, and the strengthened Azores high is related to the stationary wave change. The shift of the centers of action of the NAO is associated with the stationary wave change.
Neighbourhood search meta-heuristics for capacitated lot-sizing with sequence-dependent setups

We address a problem that often arises in industry, the multi-item capacitated-lot-sizing and scheduling problem with sequence-dependent setup times and costs. Powerful commercial solvers fail to solve even medium-sized instances of this NP-hard problem, therefore we employ a tabu search and a variable neighbourhood search meta-heuristic to solve it and compare the performance of these meta-heuristics over time. In contrast to the majority of the literature on this topic, the solution representation explicitly considers production quantities and setup variables, which enables us to develop fast search heuristics. A comprehensive set of computational experiments shows the effectiveness and efficiency of the proposed approaches in solving medium- to large-sized problems.
Reformulating Real-time Optimal Feedback based on Model Uncertainty

Abstract Model Predictive Control (MPC) and its first order approximation, the Neighboring Extremals (NE) have been used for real-time optimal control in the presence of model uncertainties for several decades. Traditionally, both MPC and NE would only correct for deviations in states considering the underlying model to be nominal - a procedure that is valid for additive disturbances. However, in the presence of model uncertainties, a simple illustrative example in this paper shows that such a MPC scheme or a NE controller could cause corrections in the wrong direction, thereby deteriorating performance. The paper, thus, addresses reformulating NE feedback considering sensitivities with respect to the model parameters. The feedback then has two components - one based on state deviations and the other based on parameter deviations. Note that this formulation also requires some primitive form of parameter estimation. The illustrative example shows the efficacy of this approach and the importance of incorporating the knowledge of parameter variations in real-time optimal control.
The strong law of small numbers

This article is in two parts, the first of which is a do-it-yourself operation, in which I'll show you 35 examples of patterns that seem to appear when we look at several small values of n, in various problems whose answers depend on n. The question will be, in each case: do you think that the pattern persists for all n, or do you believe that it is a figment of the smallness of the values of n that are worked out in the examples? Caution: examples of both kinds appear; they are not all figments! In the second part I'll give you the answers, insofar as I know them, together with references. Try keeping a scorecard: for each example, enter your opinion as to whether the observed pattern is known to continue, known not to continue, or not known at all. This first part contains no information; rather it contains a good deal of disinformation. The first part contains one theorem:
Full-field Hilbert phase microscopy using nearly common-path low coherence off-axis interferometry for quantitative imaging of biological cells

We demonstrate single shot low coherence quantitative Hilbert phase microscopy (HPM) for the reconstruction of the two dimensional (2D) phase map of biological cells. The system is based on a compact and nearly common-path high magnification Mirau-interferometric objective lens. The spatial carrier frequency of the interference fringes was increased by means of introducing tilt in one of the arms of the interferometer, thus making the system off-axis. The system is user friendly as the interference fringes and imaging of objects with high lateral and axial resolution can be obtained quickly using a low cost commercially available microscope. Experimental results for the 2D phase map of polystyrene spheres and human red blood cells (RBCs) are presented. Hilbert transform fringe analysis was used for reconstructing the phase map and refractive index (RI) of the objects. For dynamic substances which change rapidly, single shot low coherence interferometric microscopy is an important method for obtaining the phase. Experimental results with increased field-of-view and large tilt angle are also presented. It is well known that on increasing the tilt angle for improved spatial phase sampling the object remains focused in only a small area even though the field-of-view is large. This limitation was overcome by means of vertical scanning low coherence interferometry. Due to the low coherence properties of the light source the interference occurs only at the desired location of the object, i.e., where the object is sharply focused. The object was vertically scanned and the single shot interferograms were recorded for every scan and analyzed by Hilbert transform. In this way a large area of the sample can be imaged quantitatively.
The Effect of Number of Rating Scale Categories on Levels of Interrater Reliability : A Monte Carlo Investigation

A computer simulation study was designed to in vestigate the extent to which the interrater reliability of a clinical scale is affected by the number of cate gories or scale points (2, 3, 4, . ,100). Results in dicate that reliability increases steadily up to 7 scale points, beyond which no substantial increases occur, even when the number of scale poirits is increased to as many as 100. These findings hold under the follow ing conditions: (1) The research investigator has insuf ficient a priori knowledge to use as a reliable guide line for deciding on an appropriate number of scale points to employ, and (2) the dichotomous and ordinal categories being considered all have an underlying metric or continuous scale format.
Is the new Grand minimum in progress?

The sunspot numbers and polar faculae are analyzed to demonstrate that the current solar activity is close to the Grand minimum. Notably protracted Cycle 23 is found to be similar to the cycles on the eve of the Dalton and Gleissberg–Gnevyshev minima. The polar faculae as proxy of the polar field replicate variations of the sunspot cycle amplitude over the last 100 years. The weak sunspot activity of Cycle 24 is assumed to result in the weak polar field.
A hydroelastic model of hydrocephalus

We combine elements of poroelasticity and of fluid mechanics to construct a mathematical model of the human brain and ventricular system. The model is used to study hydrocephalus, a pathological condition in which the normal flow of the cerebrospinal fluid is disturbed, causing the brain to become deformed. Our model extends recent work in this area by including flow through the aqueduct, by incorporating boundary conditions that we believe accurately represent the anatomy of the brain and by including time dependence. This enables us to construct a quantitative model of the onset, development and treatment of this condition. We formulate and solve the governing equations and boundary conditions for this model and give results that are relevant to clinical observations.
Spectroscopy of supernova 1987A at 1 – 4 µm – II. Days 377 to 1114

Infrared spectroscopy of SN 1987A has continued through the second and third years of its existence, allowing unprecedented coverage of the late-time behaviour of a supernova. We present the data and their analysis. The continuum emission in the L window is interpreted in terms of dust condensation which had commenced by day 350. The mass of dust formed exceeded 3×10 −4 M ○ . , possibly by a large factor, and it probably had a clumped distribution. Forbidden lines increased in prominence, especially those of [Fe II]. The similarity of linewidths for a wide range of elements confirms extensive mixing of the ejecta. Up to day ∼500, most lines were redshifted with respect to the supernova centre of mass, possibly due to a spatially biased, clumped distribution of material
Determination of the aspect ratio statistical distribution of gold nanorods in solution from a theoretical fit of the observed inhomogeneously broadened longitudinal plasmon resonance absorption spectrum

The determination of the statistical distribution of aspect ratios of a nanorod solution is desirable for experimentally synthesized solutions. The traditional method of using transmission electron microscopy (TEM) images for size determination gives statistically incorrect values due to distortions introduced by TEM sample preparation and by difficulties in counting a sufficiently large number of rods. In the present work, we propose a method to obtain the aspect ratio distribution using the observed longitudinal surface plasmon resonance absorption spectrum of gold nanorods in solution. The observed inhomogeneously broadened spectrum is fitted with a collection of homogeneously broadened spectra of nanorods each with a specific aspect ratio and population contribution using Gans extension [Ann. Phys. 47, 270 (1915)] of Mie theory. The fit generates an aspect ratio distribution for the rods in solution from which the median value and the statistical distribution are determined. This method is statistical.
Organizational restructuring and the impact of knowledge transfer

This paper examines the impact of knowledge transfer in organizational restructuring using a computer simulation model. The study demonstrates that the direction of the change, the nature of the external environment, and the learning mechanism can all influence how knowledge transfer affects organizational performance. Specifically, the study shows that organizations may suffer the most performance degradation through a vertical structural change. It also reveals that expansions tend to cause a greater impact on organizational performance while downsizings in an unpredictable environment can also be highly risky. The study further indicates that learning can be a very effective mechanism for rebuilding organizational knowledge and buffering the negative effect of organizational expansions, though its benefit may be limited under a predictable environment or in organizational downsizings.
Current-driven perpendicular magnetization switching in Ta/CoFeB/(TaOx or MgO/TaOx) films with lateral structural asymmetry

We study the current-driven perpendicular magnetization switching in Ta/CoFeB(wedge)/[TaOx or MgO/TaOx] devices with a lateral structural asymmetry introduced by a varying CoFeB thickness. In these devices, an in-plane current can generate a field-like torque and its corresponding effective magnetic field ( HzFL) is out-of-plane, which can deterministically switch perpendicular magnetization at zero magnetic field. Experimental results indicate that the method used for breaking lateral structural symmetry greatly affects the resulting field-like torque, and that the gradient of perpendicular anisotropy, resulting from the CoFeB thickness variation, is not by itself sufficient to give rise to the current-induced HzFL. Analysis of the oxidation gradient at the CoFeB/TaOx interface indicates that the oxidation gradient may play a more important role than the gradient of magnetic anisotropy for the generation of HzFL. For practical applications, the demonstration of perpendicular magnetization switching in Ta.