Miracle-dz/UniFAR-FTUs huggingface dataset:
Enhancement of the Q value of a microring resonator by introducing curved photonic crystal waveguides

The aim of this work is to enhance the Q value of a photonic crystal microring resonator that can be used to buffer optical signals (in a pulse train). A conventional photonic crystal microring resonator having 60° bends exhibits poor confinement of light due to the radiation losses at the bending points. Hence, we replaced conventional bent waveguides with circularly curved ones. The Q value of the resulting ring resonator is measured, and we demonstrate, as an example, an eightfold enhancement of the Q value at a wavelength of 1340 nm. Finally, we also estimate the Q value of a ring waveguide that excludes the optical coupling between the input/output waveguides, showing that the replacement of a sharply bent waveguide by a curved one increases the Q value by up to 5.2 times at a wavelength of 1340 nm.
MDAS: a new multimodal benchmark dataset for remote sensing

Abstract. In Earth observation, multimodal data fusion is an intuitive strategy to break the limitation of individual data. Complementary physical contents of data sources allow comprehensive and precise information retrieval. With current satellite missions, such as ESA Copernicus programme, various data will be accessible at an affordable cost. Future applications will have many options for data sources. Such a privilege can be beneficial only if algorithms are ready to work with various data sources. However, current data fusion studies mostly focus on the fusion of two data sources. There are two reasons; first, different combinations of data sources face different scientific challenges. For example, the fusion of synthetic aperture radar (SAR) data and optical images needs to handle the geometric difference, while the fusion of hyperspectral and multispectral images deals with different resolutions on spatial and spectral domains. Second, nowadays, it is still both financially and labour expensive to acquire multiple data sources for the same region at the same time. In this paper, we provide the community with a benchmark multimodal data set, MDAS, for the city of Augsburg, Germany. MDAS includes synthetic aperture radar data, multispectral image, hyperspectral image, digital surface model (DSM), and geographic information system (GIS) data. All these data are collected on the same date, 7 May 2018. MDAS is a new benchmark data set that provides researchers rich options on data selections. In this paper, we run experiments for three typical remote sensing applications, namely, resolution enhancement, spectral unmixing, and land cover classification, on MDAS data set. Our experiments demonstrate the performance of representative state-of-the-art algorithms whose outcomes can serve as baselines for further studies. The dataset is publicly available at https://doi.org/10.14459/2022mp1657312 (Hu et al., 2022a) and the code (including the pre-trained models) at https://doi.org/10.5281/zenodo.7428215 (Hu et al., 2022b).
Feasibility study to determine correct focus by analyzing photon distributions on Geiger-mode avalanche photodiode focal plane array

A method to determine correct focus in direct detection laser radar system using Geiger-mode avalanche photodiode focal plane array (GmAPD-FPA) is proposed. It is implemented by laser pulses with controlled beam diameter and energy on a distant target. And the time-of-flight (TOF) of laser pulses are obtained for each pixel in GmAPD-FPA. With multiple laser pulses, time correlated single photon counting (TCSPC) is carried out to obtain target detection probability. Using target detection probabilities of each pixel, the photon distribution on GmAPD-FPA is acquired. The condition to determine correct focus is the minimum photon distribution in GmAPD-FPA. In theory part, the range of laser pulse energy is decided. The experiments are carried out with commercial 1x8 pixel GmAPD-FPA. The experimental results show that the focus position is founded using this method and a spatial resolution of a laser radar system is improved where the 1x8 pixel GmAPD-FPA is located in focus position.
Investigation of Temperature-Driven Ferroelectric Phase Transition via Modified Heisenberg Model: The Monte Carlo Simulation

This work studies the temperature-driven ferroelectric phase transition of ferroelectric polarization under the absence of electric field. The modified Heisenberg model in three dimensions was considered and simulated via Monte Carlo simulation. The Metropolis algorithm and the periodic boundary condition were employed. The dependence of electric polarization on temperature was investigated to define the ferroelectric phases and their structural phase transitions. From the results, with well-defined set of relevant temperature parameters, the phase dependent polarization-behavior was found with a sudden change in its behaviors at the transition points. The structure factors were also considered and supported these phase changes. This conclusively pinpointed the important of temperature-dependent parameters in modeling ferroelectric materials.
Observations of the D-band feature in the Raman spectra of carbon nanotubes

We examine the behavior of the D-band feature in the Raman spectra of single-walled carbon nanotube (SWNT) bundles, observed between 1250 and 1450 cm{sup -1}, as a function of the laser excitation energy. We used three SWNT samples with different diameters, and show that the D-band behavior of SWNTs differs from sp{sup 2} carbons, depending on whether the SWNTs are metallic or semiconducting, and shows a frequency {omega}{sub D} that is dependent on nanotube diameter.
IMPROVED ENHANCED STRAIN FOUR-NODE ELEMENT WITH TAYLOR EXPANSION OF THE SHAPE FUNCTIONS

A class of enhanced strain four-node elements with Taylor expansion of the shape function derivatives is presented. A new concept of enhancement using besides the ‘standard’ enhanced strain fields also two other enhanced fields is developed on the basis of the Hu–Washizu principle. For first-order Taylor expansion enhanced modes become uncoupled, thus only a negligible amount of computing effort for the static condensation of enhanced modes is needed. Furthermore, the formulation permits a symbolic integration, which leads to a closed-form solution for the element tangent matrix. Several numerical examples show that the element is stable, invariant, passes the patch test and yields good results especially in the highly distorted regime. © 1997 by John Wiley & Sons, Ltd.
A robust fuzzy logic approach to modelling algae biomass

Abstract Modelling of algal bloom is an ambitious and difficult topic due to the complexity of aquatic ecosystem, insufficient knowledge of the detailed processes and mechanism involved and shortage of high quality data. Owing to the ability to deal with imprecise, uncertain data or ambiguous relationships among data, fuzzy logic (FL) has proved to be a useful and practical method in algal bloom modelling. However, common to any FL modelling approach, the definition of membership functions and inference rules remains difficult. Although, generating rules directly from measurements and observations (rather than consulting the expert) has recently been explored, the procedures turn out to be quite cumbersome. In this paper, a robust FL approach is explored to derive a model directly from measurements, using expert knowledge as a reference only. Its strength lies in the capability to combine partial knowledge on processes with partially available data from observations. The approach was successfully tested in a case for the North Sea to model chlorophyll a (Chl-a) concentration. It had also been introduced to the Dutch pilot study of the European Commission project Harmful Algal Bloom Expert System, which involves 13 institutes and universities from nine EU countries. The objectives of the paper are to illustrate how the robust fuzzy model is developed.
Effect of buffer layer and substrate surface polarity on the growth by molecular beam epitaxy of GaN on ZnO

We present results on the effect of substrate surface polarity, oxygen and zinc faces, on the quality of GaN epitaxial layers grown on ZnO(0001) substrates by reactive ammonia molecular beam epitaxy. The possible effects dealing with the disparity in surface preparation of the two faces have been eliminated. Photoluminescence and reflectivity measurements demonstrate that the oxygen face leads to higher quality GaN on ZnO compared to the zinc face. We also present optical data obtained by using different low-temperature AlN, GaN, and InxGa1−xN buffer layers. The best result has been obtained with lattice-matched In0.20Ga0. 80N buffer layer.
Detection of Edges in Spectral Data

We are interested in the detection of jump discontinuities in piecewise smooth functions which are realized by their spectral data. Specifically, given the Fourier coefficients, { fk 5 ak 1 ibk}k51 N , we form the generalized conjugate partial sum S N s @ f #~x! 5 ¥ k51 N sS ND~aksin kx 2 bkcos kx! The classical conjugate partial sum, SN [ f ]( x), corresponds to s [ 1 and it is known that 2p log N SN@ f #~x! converges to the jump function [ f ]( x) :5 f ( x1) 2 f ( x2); thus, 2p log N SN@ f #~x! tends to “concentrate” near the edges of f. The convergence, however, is at the unacceptably slow rate of order 2(1/log N ). To accelerate the convergence, thereby creating an effective edge detector, we introduce the so-called “concentration factors,” sk,N 5 sS ND . Our main result shows that an arbitrary C[0, 1] nondecreasing s(z) satisfying *1/N 1 s~x! x dxOi N3 ` 2p leads
Electronic structure of multiwall boron nitride nanotubes

We report on electron energy-loss spectroscopy studies of the electronic properties of multiwall boron nitride nanotubes, in terms of the $\mathrm{B}1s$ and $\mathrm{N}1s$ excitation edges and of the q-dependent energy-loss function. The q-dependent dielectric function shows a strong dispersion in momentum of the \ensuremath{\pi} and $\ensuremath{\sigma}+\ensuremath{\pi}$ plasmons indicating that they are spatially delocalized along the tube axis as expected according to their characteristic two-dimensional graphiticlike structure, and nondispersing excitations at 11 and 12 eV. The dielectric function \ensuremath{\varepsilon} of the boron nitride nanotubes reveals an intense $\ensuremath{\pi}\ensuremath{-}{\ensuremath{\pi}}^{*}$ interband transition at 5.4 eV, which is shifted to lower energies by 0.6 eV when compared to hexagonal BN in good agreement with recent theoretical band-structure calculations of boron nitride nanotubes.
Effects of end-of-range dislocation loops on transient enhanced diffusion of indium implanted in silicon

Transient enhanced diffusion of indium implanted in silicon is studied in the presence of the end-of-range (EOR) damage layer. To investigate the effect of EOR defects on the indium diffusion, the samples that were implanted with indium at a high dose (1×1013–5×1014/cm2) sufficient to produce the amorphous layer were prepared. Transmission electron microscopy measurements and Rutherford backscattering spectrometry reveal the amorphization threshold of indium implantation is around 5×1013/cm2 for 200 keV, 115In+ implanted with 100 μA/cm2 beam current density at room temperature. These results are consistent with Monte Carlo simulation of implantation. Monte Carlo simulations indicate the deviation from the plus one model due to the mass effect of indium. After amorphization, following both RTA at 1000 °C and furnace anneal at low temperature (650 and 850 °C) in nitrogen ambient showed the formation of extrinsic EOR dislocation loops below the original amorphous/crystalline interface. During this process, s.
Book Reviews : The Mismeasure of Man Stephen Jay Gould New York: W. W. Norton, 1981, 352 pp., $14.95

Item: The publication of results from the Army Alpha test influenced the passage of the Immigration Restriction Act of 1924. It is estimated that as many as six million Europeans were barred under the act from immigrating to the U.S. between 1924 and World War II. &dquo;The paths to destruction are often indirect, but ideas can be agents as sure as guns and bombs&dquo; (p. 233). Item: Test scores from the Stanford-Binet scale sometimes were used in the State of Virginia to justify the application of the Virginia sterilization statute, upheld in 1927 by the LJ.S. Supreme Court. It
KINETIC ALFVÉN WAVE INSTABILITY DRIVEN BY FIELD-ALIGNED CURRENTS IN SOLAR CORONAL LOOPS

Magneto-plasma loops, which trace closed solar magnetic field lines, are the primary structural elements of the solar corona. Kinetic Alfvén wave (KAW) can play an important role in inhomogeneous heating of these magneto-plasma structures in the corona. By the use of a low-frequency kinetic dispersion equation, which is presented in this paper and is valid in a finite-β plasma with Q < β < 1 plasma (where β is the kinetic to magnetic pressure ratio and Q = me/mi is the mass ratio of electrons to ions), KAW instability driven by a field-aligned current in the current-carrying loops in the solar corona is investigated. The results show that the KAW instability can occur in wave number regimes 0 < kz < kcz and 0 < k⊥ < kc⊥, and that the critical wave numbers kcz and kc⊥ and the growth rate both considerably increase as the drift velocity VD of the current-carrying electrons increases in the loops. In particular, for typical parameters of the current-carrying loops in the solar corona this instability mechanism results in a high growth rate of KAWs, ωi ∼ 0.01–0. 1ωci ∼ 103–104 s−1. The results are of importance in understanding the physics of the electric current dissipation and plasma heating of the current-carrying loops in the solar corona.
Finite-circle method for component approximation and packing design optimization

In this article, the finite-circle method is introduced for 2D packing optimization. Each component is approximated with a group of circles and the non-overlapping constraints between components are converted into simple constraints between circles. Three new algorithms—the bisection algorithm, the three-step algorithm, and the improved three-step algorithm with gap—are developed to automatically generate fewer circles approximating the components. The approximation accuracy, the circle number, and the computing time are analyzed in detail. Considering the fact that packing optimization is an NP-hard problem, both genetic and gradient-based algorithms are integrated in the finite-circle method to solve the problem. A mixed approach is proposed when the number of components is relatively large. Various tests are carried out to validate the proposed algorithms and design approach. Satisfactory results are obtained.
Bias reduction of a tail index estimator through an external estimation of the second-order parameter

In this paper, we first consider a class of consistent semi-parametric estimators of a positive tail index γ, parameterised in a tuning or control parameter α. Such a control parameter enables us to have access, for any available sample, to an estimator of the tail index γ with a null dominant component of asymptotic bias, and consequently with a reasonably flat mean squared error pattern, as a function of k, the number of top-order statistics considered. Such a control parameter depends on a second-order parameter ρ, which will be adequately estimated so that we may achieve a high efficiency relative to the classical Hill estimator, provided we use a number of top-order statistics larger than the one usually required for the estimation through the Hill estimator. An illustration of the behaviour of the estimators is provided, through the analysis of the daily log-returns on the Euro–US$ exchange rates.
Global properties of infrared bright galaxies

Infrared flux densities of 182 galaxies, including 50 galaxies in the Virgo cluster, were analyzed using IRAS data for 12, 25, 60, and 100 microns, and the results were compared with data listed in the Point Source Catalog (PSC, 1985). In addition, IR luminosities, L(IRs), colors, and warm dust masses were derived for these galaxies and were compared with the interstellar gas masses and optical luminosities of the galaxies. It was found that, for galaxies whose optical diameter measures between 5 and 8 arcmin, the PSC flux densities are underestimated by a factor of 2 at 60 microns, and by a factor of 1.5 at 100 microns. It was also found that, for 49 galaxies, the mass of warm dust correlated well with the H2 mass, and that L(IR) correlated with L(H-alpha), demonstrating that the L(IR) measures the rate of star formation in these galaxies. 74 refs.
DEDUCTION OF GROUND IMPEDANCE FROM MEASUREMENTS OF EXCESS ATTENUATION SPECTRA

An efficient numerical method of deducing ground-surface impedance from measurements of short-range propagation from a point source is proposed. The method involves finding the root of a complex equation and uses the fact that the classical approximation for the spherical wave-reflection coefficient near grazing incidence is an analytic function of the impedance. Examples of fitting measured excess-attenuation spectra are given. Methods for ensuring the uniqueness of the resulting impedance fits are discussed. Subsequent deductions of parameters in a two-parameter impedance model are also considered and exemplified.
Hydrodynamic simulations of cataclysmic variable accretion discs in outburst

We study the outburst phase of cataclysmic variable (CV) accretion discs in the (r, π) plane with full hydrodynamics. Vertically the disc is treated using the one-zone model of Stehle & Spruit, which allows us to follow the fundamental mode of vertical disc oscillations correctly. α-type shear viscosity (Shakura & Sunyaev) and energy loss at the surface of the accretion disc by radiation are included. We run accretion disc models with different masses M1 and M2 for the primary and the secondary stars and different values of α. In all calculations we observe strong spiral shock arms, which dominate the disc evolution on a hydrodynamical time-scale. In cases where the surface mass density Σ (r) decreases with radius r the disc pattern is stable. In cases where Σ (r) increases with r we observe a quasi-periodic cycle of disc size. During the phase where the disc is large, the spiral arm close to the L1 point connects to the secondary, and about 1 per cent of the total disc mass is lost to the secondary per cycle. However, in none of our calculations are we able to find an eccentric and precessing accretion disc, even though the disc edge is outside the 3:1 tidal resonance radius R31. Our calculations therefore cannot confirm the tidal instability model, presently the only model for superhumps in SU UMa CVs during superoutbursts.
1E 1207.4–5209: The Puzzling Pulsar at the Center of the Supernova Remnant PKS 1209–51/52

A second Chandra observation of 1E 1207.4-5209, the central source of the supernova remnant (SNR) PKS 1209-51/52, allowed us to confirm the previously detected period of 424 ms and, assuming a uniform spin-down, estimate the period derivative, ~ (0.7-3) × 10-14 s s-1. The corresponding characteristic age of the pulsar, P/2 ~ 200-900 kyr, is much larger than the estimated age of the SNR, ~7 kyr. The values of the spin-down luminosity, ~ (0.4-1.6) × 1034 ergs s-1, and conventional magnetic field, B ~ (2-4) × 1012 G, are typical for a middle-aged radio pulsar, although no manifestations of pulsar activity have been observed. If 1E 1207.4-5209 is indeed the neutron star formed in the same supernova explosion that created PKS 1209-51/52, such a discrepancy in ages could be explained either by a long initial period, close to its current value, or, less likely, by a very large braking index of the pulsar. Alternatively, the pulsar could be a foreground object unrelated to the SNR, but the probability of such a coincidence is very low.
Constraints on the standard model extension with binary pulsars

Abstract Under the standard model extension (SME) framework, Lorentz invariance is tested in five binary pulsars: PSR J0737-3039, PSR B1534+12, PSR J1756-2251, PSR B1913+16 and PSR B2127+11C. By analyzing the advance of periastron, we obtain the constraints on a dimensionless combination of SME parameters that is sensitive to timing observations. The results imply no evidence for the break of Lorentz invariance at 10−10 level, one order of magnitude larger than previous estimation.
High field-effect mobility amorphous InGaZnO transistors with aluminum electrodes

We report on the device characteristics of amorphous indium gallium zinc oxide thin-film transistors (TFTs) with aluminum (Al) electrodes. The TFTs exhibited a high performance with a field-effect mobility of 11.39 cm2/V s, a subthreshold swing of 181 mV/ decade, and an on-off ratio of 107. Further improvement in device performance was achieved by doping the source/drain contact regions, resulting in an enhanced mobility of 16.6 cm2/V s at an operating voltage as low as 5 V.
Effect of Dielectrophoretic Forces on the Bénard Instability

When a fluid is heated from below, there is a critical temperature gradient above which the fluid becomes unstable and convection results. The effect of dielectrophoretic forces on this critical temperature gradient is studied. Dielectrophoretic forces are caused by an electric field and a gradient in dielectric constant. The principle of exchange of stabilities is shown to hold for a certain set of boundary conditions. Variational principles are derived for various boundary conditions. These variational principles and the Galerkin method are then used to find approximate solutions for the critical temperature gradient as a function of the wavelength and the electric field.
Condensation enhancement by means of electrohydrodynamic techniques

Short state-of-the-art on the enhancement of condensation heat transfer techniques by means of condensate drainage is presented in this paper. The electrohydrodynamic (EHD) technique is suitable for dielectric media used in refrigeration, organic Rankine cycles and heat pump devices. The electric ﬁeld is commonly generated in the case of horizontal tubes by means of a rod-type electrode or mesh electrodes. Authors proposed two geometries in the presented own experimental investigations. The ﬁrst one was an electrode placed just beneath the tube bottom and the second one consisted of a horizontal ﬁnned tube with a double electrode placed beneath the tube. The experimental investigations of these two conﬁgurations for condensation of refrigerant R-123 have been accomplished. The obtained results conﬁrmed that the application of the EHD technique for the investigated tube and electrode arrangement caused signiﬁcant increase in heat transfer coeﬃcient. The condensation enhancement depends both on the geometry of the electrode system and on the applied voltage.
Amplification of solitary optical waves in fibers with positive group velocity dispersion

Solitary optical waves with characteristic red frequency shift have been numerically identified in fibers with positive group velocity dispersion in the presence of amplification by semiconductor amplifiers. Influence of the Henry factor, the net gain, gain saturation characteristics, and frequency modulation on the frequency shift of the observed solitary optical waves has been examined. Normalized pulse energy as a function of the gain saturation characteristics has been studied.