Miracle-dz/UniFAR-FTUs huggingface dataset:
Optical nonlinearity characteristics of crystalline InSb semiconductor thin films

The intensity-dependent nonlinear absorption and refraction characteristics of crystalline InSb thin films are investigated by z-scan method at 405 nm laser wavelength. Results show that the nonlinear absorption coefficient of crystalline InSb thin films is in the order of ∼ + 10−2 m W−1, and the nonlinear refractive index is in the order of ∼ + 10−9 m2 W−1. Variable-temperature ellipsometric spectroscopy measurements and electronic process analyses as well as theoretical calculations are employed to discuss the internal mechanisms responsible for the giant optical nonlinearity. Analysis results indicate that the nonlinear absorption mainly stems from the laser-induced free-carrier absorption effect, whereas the nonlinear refraction is mainly from thermal effect due to band gap shrinking and carrier effect due to the transition process of electrons, respectively. These characteristics may be responsible for the super-resolution effect in nano-optical information storage.
Some more uniformly convex spaces

Let {Bi,i = l, 2, • . } be a sequence of Banach spaces, and define B = P\Bi} to be the space of sequences b={bi} with biÇ^Bi and Ml = ( l > I N h ) 1 / p < °°> 1 < £ < °°. I t is known that B, normed in this way, is also a Banach space. Boas showed that if Bi = l for all i or if Bi — L for all i then B is uniformly convex. Since then I have shown that if B{ — l or L, \<pi< oo, and if the sequence {pi} is not bounded away from 1 and oo (that is, if there do not exist Km ^M < oo with m^pi^M for all i), then B is not uniformly convex and cannot be renormed to an isomorphic uniformly convex space. One purpose of this note is to fill in the gap between these results by means of the following theorem.
GROUPS AND IDENTITIES

ABSTRACT The notion of large set has been introduced in[3] to generalize the concept of generic sets in algebraic groups. A subset of an arbitrary group is said to be (left) large if any finite collection of (left) translates has non-empty intersection. It was proved that if the group is residually nilpotent-by-finite then any equation which is satisfied in a large set holds in the entire group. [3] In this paper, we study large periodicity, in other words groups which satisfy on a large set. This problem has an affirmative solution for and a negative one for . Motivated by the fact that a finite union of Zariski closed sets is also a Zariski closed set, we shall also treat, at least partially, the problem of large equational disjunctions in nilpotent-by-finite groups.
Cartwright on laws and composition

Cartwright attempts to argue from an analysis of the composition of forces, and more generally the composition of laws, to the conclusion that laws must be regarded as false. A response to Cartwright is developed which contends that properly understood composition poses no threat to the truth of laws, even though agreeing with Cartwright that laws do not satisfy the "facticity" requirement. My analysis draws especially on the work of Creary, Bhaskar, Mill, and points towards a general rejection of Cartwright's view that laws, especially fundamental laws, should be seen as false.
Short-range evolution of small perturbations in a barotropic model

The short-range evolution of small initial errors is numerically investigated with an f -plane shallow-water model. It is shown that this evolution can be approximated by a linearized model for meteorologically realistic situations, and for ranges of up to about 48 hours. The results are consistent with a description of the slow manifold as an attracting set along which the dynamics of the flow is dominated by an instability process. As a consequence of the relatively large time scale for the meteorologically significant components of the flow, the linear model valid for short periods can be further simplified to a constant coefficient model describing only the evolution of the large-scale components of the error. The possible implications of this result for the improvement of assimilation procedures are briefly discussed. DOI: 10.1111/j.1600-0870.1988. tb00408.x
A critical analysis of the ultraviolet temperature scale of the helium-dominated DB and DBV white dwarfs

The temperatures of the hottest of the DB and of some of the variable DBV white dwarfs have been reanalyzed, using a new helium-rich model atmosphere grid and archival IUE data. The grid covers variations in the effective temperature, surface gravity, and trace hydrogen abundance. Significantly lower temperatures than those found by earlier investigations are found. This has influence on the issue of which mixing-length theory is the best one for treatment of convection in DB white dwarfs. The prototype of the DBV stars, GD 358, is given particular attention in view of the recently reported HE II 1640-A line. The sensitivity of the new results to input physics is analyzed. It is found that uncertainties in Stark broadening parameters, convective efficiency, and equation of state and the assumptions of a fixed gravity (log g = 8) and a negligible abundance of hydrogen can at most give an error in the effective temperature of 400 K for a typical DB star. The uncertainty on the absolute calibration of the IUE cameras and the effect of small interstellar reddening dominate the error analysis. 46 refs.
Impact Ionization Behavior in Bulk Fin Field Effect Transistors with Fin Body Width and Bias Conditions

The impact ionization behavior of bulk fin field effect transistors (FinFETs) was investigated with respect to fin body width (Wfin) and bias conditions. As fin width decreases to less than about 50 nm, the effect of parasitic source/drain series resistance becomes significant, resulting in a decrease in the impact ionization rate due to the increasing voltage drop across the resistance. We analyzed the ISUB/ID trend depending on the bias conditions (VGS=VDS and VGS=VDS/2) for devices with a Wfin thicker than 50 nm. Through two-dimensional device simulation, we showed the voltage drop and the peak electron temperature for various Wfin. It was also shown that the contact resistivity between the source/drain and the metal electrode is very important in the bulk FinFET with a very thin fin width.
Experimental observation of the relaxation time of the order parameter in superconductors

The relaxation time (tau) for the superconducting energy gap was measured. It is shown that near the superconducting transition temperature tau/ subc/ the relaxation time diverges. By also measuring the equilibrium gap $delta$ tau-proportional$delta$$sup -1$ is found very near T/subc/ in agreement with the calculations of Schmid and Shon. (AIP)
Investigation of the EXAFS Cumulants of Silicon and Germanium Semiconductors by Statistical Moment Method: Pressure Dependence

Pressure dependence of Extended X-ray Absorption Fine Structure (EXAFS) cumulants of silicon and germanium have been investigated using the statistical moment method (SMM). Analytical expressions of the first and second cumulants of silicon and germanium have been derived. The equations of states for silicon and germanium semiconductors have been also obtained using which the pressure dependence of lattice constants and volume of these semiconductors have been estimated. Numerical results using the developed theories for these semiconductors are found to be in good and reasonable agreement with those of the other theories and with experiment.
Fast fractal image compression using the Hadamard transform

A new algorithm for fractal image compression is developed to speed up the encoder. This new method converts image blocks into frequency-like domains using the Hadamard transform, in which the computations of the best matched are performed. At each search entry, the best mean square error computations of the eight dihedral symmetries are reformulated into the form of inner products. By a precise derivation, all redundant computations are completely avoided. With this improved technique, the complexity of the encoder is substantially reduced. A simulation shows that, with the same PSNR and compression ratio, the new method requires less computation time than the baseline method.
High resolution electron microscopy study of damage created in Si‐implanted InP

{011} oriented InP crystals were implanted with 50 keV Si+ ions (doses: 5×1012 and 1014 Si/cm2). The individual cluster density and size were compared with those previously obtained in {001} oriented crystals. The high‐resolution electron microscopy observations are consistent with an amorphous nature of these strained clusters. Further annealing of the amorphous zone obtained at the highest implantation dose shows lattice deformation or microtwins in the epitaxial recrystallized InP. Moreover, many InP undetermined and incoherent ‘‘precipitates’’ are observed.
The role of the equatorial electrojet in the evening ionosphere

This paper focuses on the role of the equatorial E region in the electrodynamics of the evening ionosphere. The influence and reaction of the electrojet current on the equatorial ionosphere at sunset is investigated using a field line integrated, one-dimensional, electrodynamic model. The one-dimensional, time-varying model predicts the divergence of the horizontal current of the equatorial electrojet for a given time variation of the horizontal electric field. The negative divergence of the horizontal current during the evening hours provides a net upward current out of the equatorial E region into the integrated ionosphere of higher equatorial altitudes (and equivalent latitudes). This upward current affects the vertical electric field magnitudes and subsequent horizontal plasma drifts of the overlying ionosphere. The model allows for chemical recombination and dynamic redistribution of ionization within the electrojet region under the assumption that the profile of the ionization density along a field line is proportional to the chemical equilibrium profile. The eastward horizontal electric field and the net upward current during the 2 hours after sunset combine to lift the ionization out of the E region resulting in ionization densities less than the equilibrium values. As the ionization densities (conductivities) are reduced, the electrodynamics of the equatorial ionosphere is altered. This model of the equatorial electrojet current divergence can be used as a lower boundary to global, two-dimensional models of the equatorial electric fields. Finally, it is proposed that the equatorial electrojet current near sunset has a significant role in the determination of the postsunset enhancement of the horizontal electric field. The electrojet region provides the best avenue for current to be channeled from the dayside to meet the vertical current demands of the F region neutral wind dynamo after sunset. The conductivity reduction in the E region due to the recombination of ionization and the plasma uplift enhances the horizontal (eastward) electric field and thereby increases the speed of the uplift. Thus the dynamic adjustment of ionization has an unstable, feedback relationship with the electric fields which may explain the night to night variability of the horizontal electric field enhancement.
Enabling online learning: who are the educators?

This chapter examines the teaching activities that educators engage in, in the context of Massive Open Online Courses (MOOCs). Data was gathered from 28 professionals involved in teaching on seven different MOOCs on the FutureLearn (FL) platform, using a multiple case study approach. Participants’ prior experience was in face-to-face environments. The analysis uncovers the roles of people who carry out the teaching in MOOCs, and the wide variety of teaching activities in these settings. It provides a nuanced definition of teaching online courses (MOOCs), an activity which demands subject matter expertise, pedagogical decisions about the learning design, and technical skills. The need for this range of skills means professional development in these areas is crucial. This investigation contributes to a conceptualisation of who the educators are in online learning contexts and of what teaching means in MOOCs and in other online or blended learning contexts.
Gauge field configurations in curved spacetimes. II

We study classical solutions of SU(2) Yang-Mills field equations, with or without coupled scalar fields, in curved spacetimes. We consider, essentially, only static, spherically symmetric background metrics, for both Lorentz and Euclidean signatures. Section I presents the motivation for searching such solutions. In Sec. II, the equations of motion for a class of Ansatze and several static solutions are given, namely a class of scalar fields compatible with a point monopole and particular solutions, for gauge fields alone, in background Schwarzschild and de Sitter metrics, respectively. Some interesting properties are discussed. In Sec. III a finite-action, Prasad-Sommerfield-type solution is constructed for the O(4,1) de Sitter metric. In Sec. IV it is shown how one single, simple de Sitter solution can lead to various well-known flat-space solutions, and to new ones, through a systematic exploitation of conformal equivalence. Self-duality constraints are formulated explicitly in Sec. V for a static spherically symmetric metric. Certain results for the Robinson-Bertotti metric are given in Sec. VI.
Estimators of the Squared Cross-Validity Coefficient: A Monte Carlo Investigation

A monte carlo experiment was used to evaluate four procedures for estimating the population squared cross-validity of a sample least squares re gression equation. Four levels of population squared multiple correlation (Rp 2) and three levels of number of predictors (n) were factorially crossed to produce 12 population covariance matrices. Ran dom samples at four levels of sample size (N) were drawn from each population. The levels of N, n, and RP 2 were carefully selected to ensure relevance of simulation results for much applied research. The least squares regression equation from each isample was applied in its respective population to obtain the actual population squared cross-validity (Rcv 2). Estimates of Rcv 2 were computed using three formula estimators and the double cross-validation procedure. The results of the experiment demon strate that two estimators which have previously been advocated in the literature were negatively biased and exhibited poor accuracy. The negative bias for these two estimators increased as Rp 2 de creased and as the ratio of N to n decreased. As a consequence, their biases were most evident in small samples where cross-validation is imperative. In contrast, the third estimator was quite accurate and virtually unbiased within the scope of this simulation. This third estimator is recommended for applied settings which are adequately approxi mated by the correlation model.
Magnetic properties of single crystal EuCo2As2

Magnetization measurements at ambient pressure have been performed on single crystal EuCo2As2, a compound having a similar crystalline structure as the pressure-induced EuFe2As2 superconductor. Similar to the magnetic characteristics of EuFe2As2 at ambient pressure, the effective paramagnetic moment at high temperatures arises primarily from the Eu2+ spins, with the Eu2+ spins ordering antiferromagnetically below 39 K. Also, a strong anisotropic behavior is found below this ordering temperature in both magnetic field and temperature dependences. While the magnetization at the lowest temperatures increases nearly linearly with field for fields parallel to the c-axis, the magnetization for fields parallel to the ab-plane exhibits a step-like behavior before further increasing linearly to the highest applied field of 5.0 T. This behavior can be explained in terms of a spin-reorientation of the Eu2+ spins being in an A-type antiferromagnetic structure. However, unlike for EuFe2As2, no evidence is found for an.
Subharmonic Dynamo Action in the Roberts Flow

The paper deals with the dynamo action of the Roberts flow, that is, a flow depending periodically on two cartesian coordinates, X and Y , but being independent of the third one, Z . In particular the case is considered in which the magnetic fields, which are periodic in X, Y and Z , have period lengths in the XY -plane being integer multiples of that of the flow. Two approaches are used. Firstly, the equations governing the magnetic field are reduced to a matrix eigenvalue problem, which is solved numerically. Secondly, a mean magnetic field is defined by averaging over proper areas in the XY -plane, corresponding equations are derived, in which the induction effect of the flow occurs as an anisotropic f -effect, and analytic solutions are given. The results are of particular interest for the Karlsruhe dynamo experiment, which works with a Roberts type flow consisting of 52 cells inside a cylindrical volume. In order to check the reliability of predictions concerning self-excitation based on the mean-field approach, analogous predictions are derived for a rectangular box containing 50 cells, and are compared with results obtained with the help of direct solutions of the eigenvalue problem mentioned. It turns out that the simple mean-field approach in general underestimates the requirements for self-excitation. The corresponding results agree with those obtained in the subharmonic approach only if the side length L of the box, its height H and the edge length l of a spin generator satisfy $ L \gg H \gg l $ . In Appendix B, some comments on previous results concerning $\cal {ABC}$ dynamos are made in the light of the subharmonic formalism used in the paper.
Downscaling Surface Albedo to Higher Spatial Resolutions With an Image Super-Resolution Approach and PROBA-V Satellite Images

For bifacial solar photovoltaic panels, surface albedo plays a crucial role in estimating the radiant energy. Since land surfaces are heterogeneous, the actual albedo of the surface where the solar photovoltaic panel is placed can vary widely and its temporality and sparsity present a significant challenge for renewable energy engineers. This paper develops a new image super-resolution deep learning model based on convolutional neural network to generate high resolution spatial representations of surface albedo from coarse resolution remote sensing-based data. For selected Australian locations, we generated a higher resolution surface albedo using imagery from PROBA-V/SPOT Earth Observation satellites. We proposed a Deep Downscaling Spectral Model with Attention (DDSA) with the capability of processing 10-day albedo images captured at a relatively low (≈ 1 km) resolution. The proposed DDSA was then applied to downscale observed surface albedo and generate predicted albedo at 500 m, 333 m and 250 m resolutions. The proposed model was benchmarked with alternative deep learning, super-resolution approaches: Super-Resolution Convolution Neural Network (SRCNN), Enhanced Deep Super-Resolution network (EDSR), Efficient Sub-Pixel Convolutional Neural Network (ESPCN) and Residual Dense Network (RDN). The results showed that the proposed DDSA model outperformed all comparative models in terms of the mean square error (MSE) <inline-formula> <tex-math notation="LaTeX">$\approx ~0.0041$ </tex-math></inline-formula>, signal-to-noise ratio (PSNR) <inline-formula> <tex-math notation="LaTeX">$\approx ~39.471$ </tex-math></inline-formula>, Structural Similarity Index (SSIM) <inline-formula> <tex-math notation="LaTeX">$\approx ~0.999$ </tex-math></inline-formula> vs. an MSE <inline-formula> <tex-math notation="LaTeX">$\approx $ </tex-math></inline-formula> [0.0140-0.0387], PSNR <inline-formula> <tex-math notation="LaTeX">$\approx $ </tex-math></inline-formula> [29.761-33.850], SSIM <inline-formula> <tex-math notation="LaTeX">$\approx $ </tex-math></inline-formula> [0.9994-0.999]). We also cross-validated the downscaled images with satellite imagery and ground-based observations, which reaffirmed the proposed DDSA model’s ability to produce high resolution surface albedo maps and its potential applications for granular scale tracking and mapping solar energy where bifacial solar photovoltaic panels are placed.
Estimation of high-dimensional vector autoregression via sparse precision matrix

We consider the problem of estimating sparse Vector Autoregression (VAR) via penalized precision matrix. This matrix is the output of the underlying directed acyclic graph of the VAR process, whose zero components correspond to the zero coefficients of the graphical representation of the VAR. The sparsity-based precision matrix estimator is deduced from the D-trace loss with convex and non-convex penalty functions. We establish the consistency of the penalized estimator and provide the conditions for which all true zero entries of the precision matrix are actually estimated as zero with probability tending to one. The relevance of the method is supported by simulated experiments and a real data application.
A Systematic Review and Meta-Analysis of Continuous Subcutaneous Insulin Infusion vs. Multiple Daily Injections in Type-2 Diabetes

Diabetes mellitus (DM) has a growing prevalence worldwide, even in developing countries. Many antidiabetic agents are used to improve glycemic control; however, in cases of an insufficient outcome, insulin is administered. Yet, the timing of proper insulin administration is still a subject of intense research. To date, there have been no recommendations or guidelines for the use of continuous subcutaneous insulin infusion (CSII) in Type 2 Diabetes Mellitus (T2DM). In the present study, we have performed a meta-analysis to evaluate the use of CSII in patients with T2DM. An extensive literature search was conducted through the electronic databases Pubmed, Clinicaltrials.gov, and Cochrane Central Register of Controlled Trials (CENTRAL) from October 2019–May 2022, for interventional studies related to T2DMI and CSII versus multiple daily injections (MDI). We included articles published in the English language only, yielding a total of thirteen studies. We found better outcomes in patients receiving CSII, in regard to glycated hemoglobin (HbA1c) and total insulin dose. In contrast, fasting plasma glucose and body weight did not show statistically significant differences between the two groups. Our analyses showed that CSII could be beneficial in patients with T2DM in order to achieve their glucose targets.