Miracle-dz/UniFAR-FTUs huggingface dataset:
A Novel Global Harmony Search Algorithm for Nonnegative Linear Least Squares

Nonnegative Linear Least Squares (NLLS) is an important optimization problems, which often appears in processing the physical data. In this paper, we use a recently proposed algorithm named Novel Global Harmony Search (NGHS) for solving NLLS problems. Numerical results are reported which demonstrate very good computational performance.
Embedded turbulence model in numerical methods for hyperbolic conservation laws

The paper describes the use of numerical methods for hyperbolic conservation laws as an embedded turbulence modelling approach. Different Godunov‐type schemes are utilized in computations of Burgers' turbulence and a two‐dimensional mixing layer. The schemes include a total variation diminishing, characteristic‐based scheme which is developed in this paper using the flux limiter approach. The embedded turbulence modelling property of the above methods is demonstrated through coarsely resolved large eddy simulations with and without subgrid scale models. Copyright © 2002 John Wiley & Sons, Ltd.
Active feedback wide-field optical low-coherence interferometry for ultrahigh-speed three-dimensional morphometry

A novel optical interferometric scheme for ultrahigh-speed three-dimensional morphometry is proposed. The system is based on wide-field optical coherence tomography (WF-OCT) but with optically chopped illumination. The chopping frequency is feedback-controlled to be always matched with the Doppler frequency of the OCT interferometer, which provides an efficient page-wide demodulation suitable for ultrahigh-speed volumetric imaging. To compensate the unwanted variation in the OCT Doppler frequency of the system, the illumination frequency is phase-locked with an auxiliary laser interferometer which shares the reference arm with the OCT interferometer. The two-dimensional (2D) interference signals projected on the 2D array pixels of a 200 Hz CCD are accumulated during one imaging frame of the CCD. Then, each pixel of the CCD demodulates the OCT signal automatically. Owing to the proposed active frequency-locked illumination scheme, the demodulation does not depend on the variation in the axial scanning speed. Volumetric topograms or/and tomograms of several samples were achieved and rendered with a sensitivity of 58 dB at an axial scan speed of 0.805 mm s−1.
HIGHER-ORDER PARAMETER UNIFORM CONVERGENT SCHEMES FOR ROBIN TYPE REACTION-DIFFUSION PROBLEMS USING ADAPTIVELY GENERATED GRID

In this article, a singularly perturbed reaction-diffusion problem with Robin boundary conditions, is considered. In general, the solution of this problem possesses boundary layers at both the ends of the domain. To solve this problem, we propose a numerical scheme, involving the cubic spline scheme for boundary conditions and the classical central difference scheme for the differential equation (DE) at the interior points. The grid is generated by the equidistribution of a positive monitor function. It has been proved that classical forward–backward approximation for mixed type boundary conditions, gives first-order convergence, whereas our proposed cubic spline scheme provides second-order accuracy independent of the perturbation parameter. Numerical experiments have been provided to validate the theoretical results.
Finite-Amplitude Wave Activity and Mean Flow Adjustments in the Atmospheric General Circulation. Part II: Analysis in the Isentropic Coordinate

AbstractThe finite-amplitude wave activity diagnostic developed for quasigeostrophic (QG) flows in Part I is extended to the global primitive equation system in the isentropic coordinate. The Rossby wave activity density A is proportional to Kelvin’s circulation around the wavy potential vorticity (PV) contour minus that around the zonal circle that encloses the same isentropic mass. A quasi-conservative, eddy-free reference state flow uREF is constructed from the observed Kelvin’s circulation by zonalizing the PV contours conservatively while enforcing gradient balance. The departure of the observed zonal-mean flow of the atmosphere from the reference state is defined as the net adjustment by the eddies. Then Δu is further partitioned into the direct eddy drag −A and the residual impulse ΔuR consistent with the time-integrated transformed Eulerian mean (TEM) zonal-wind equation.The analyzed climatological-mean wave activity in the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-.
A Newton method for solving the inverse scattering problem for a sound-hard obstacle

We present a Newton method for solving the ill-posed and nonlinear inverse scattering problem. For its foundation we establish the Frechet differentiability of the far-field operator with respect to the boundary and show that the Frechet derivative can be obtained as the solution of a hypersingular integral equation. In order to derive the right-hand sides of this integral equation we use a quadrature method. We describe the numerical solution method and give some numerical results.
Coarse-grained diffusion distance for community structure detection in complex networks

One of the most relevant features of complex networks representing real systems is the community structure. In this paper, we extend the measure of diffusion distance between nodes in a network to a generalized form on the coarse-grained network with data parameterization via eigenmaps. This notion of proximity of meta-nodes in the coarse-grained networks reflects the intrinsic geometry of the partition in terms of connectivity of the communities in a diffusion process. Nodes are then grouped into communities through an agglomerative hierarchical clustering technique under this measure and the modularity function is used to select the best partition of the resulting dendrogram. The present algorithm can identify the community structure with a high degree of efficiency and accuracy. An appropriate number of communities can be automatically determined without any prior knowledge about the community structure. The computational results on several artificial and real-world networks confirm the capability of the algorithm.
Stellar Population Properties and Formation and Evolution Research of Nearby Galaxies by Stellar Population Synthesis Models

Online material: color figure Nearby galaxies are good tracers to study the galactic formation and chemical evolution. Also, detailed analyses for the different components of these galaxies, such as bulge, disk, spiral arms, H II regions, interstellar medium and even individual stars, can be made by imaging of high resolution and spectroscopy of high quality. In my dissertation, the evolutionary stellar population synthesis (EPS) models are used to study two nearby spiral galaxies, NGC 628 and M31, based on the multiband photometric data and spectral data, respectively. NGC 628 is a face-on spiral galaxy with two symmetric inner arms and multiple long and continuous outer arms. It has an apparent size of about 10′ and thus it is included in various photometric surveys of nearby galaxies. Light decomposition and color distributions reveal that this galaxy has a disklike bulge (i.e., pseudobulge). More and more evidence shows that this kind of bulge grows via the secular evolution of the disk (Kormendy & Kennicutt 2004). Moreover, H I observations indicate that this galaxy is isolated, so it is an excellent object to investigate the secular evolution history of a single galaxy. Therefore, we use multiband photometric data from different surveys and telescopes to explore the spatially resolved stellar population properties and probe the structures and possible evolution history of this galaxy (Zou et al. 2011a). We obtain panchromatic spectral energy distribution (SED) for each pixel of the galaxy in multiband photometric images ranging from ultraviolet (Galaxy Evolution Explorer and XMM Optical Monitor), optical (15 intermediate bands in Beijing-Arizona-Taiwan-Connecticut [BATC] survey) and infrared (Two Micron All Sky Survey and Spitzer Space Telescope). These SEDs are compared with the EPS models to
Carrier recombination losses in inverted polymer: Fullerene solar cells with ZnO hole-blocking layer from transient photovoltage and impedance spectroscopy techniques

In this study, full coincidence between impedance spectroscopy and transient photovoltage techniques in measuring recombination kinetics of photogenerated charge carriers in inverted polymer:fullerene organic solar cells with ZnO hole-blocking layer is reported. Carrier lifetime exhibits values at illumination intensities near 1 sun within the microseconds time scale. Photogenerated charge carrier density attains values within 1015–1016 cm−3. Decay kinetics is analyzed by means of a bimolecular recombination law with a recombination coefficient slightly dependent on the charge density, which lies within the order of k ∼ 10−12 cm3 s−1. It is also demonstrated that inverted-processed cells exhibit capacitance, recombination resistance, and lifetime parameters comparable to those extracted from regular cells, despite the great differences between the contact structures of these kinds of devices.
Computational study on entanglement length and pore size of carbon nanotube buckypaper

In this letter, both entanglement length and pore size of carbon nanotube (CNT) buckypaper are studied numerically and found to scale with a characteristic length EI/γ, where EI and γ denote the bending stiffness and binding energy of a CNT, respectively. For EI/γ 40 nm, CNT “ring”/“racket” structures dominate the buckypaper, exhibiting longer entanglement length and larger pore size. The acquired understanding of microscopic structures allows us to propose that CNT buckypaper with different mechanical properties and pore size can be designed through the choice of EI/γ values.
Growth of submicron AlGaN/GaN/AlGaN heterostructures by hydride vapor phase epitaxy (HVPE)

Multilayer AlGaN/GaN epitaxial structures were grown on SiC by HVPE method. Characterization of the grown structures was performed using SEM, SIMS, mercury probe, electroluminescence and photoluminescence techniques. Thicknesses of nitride layers in nanometer range were achieved. Stimulated emission from double confined heterostructure grown by HVPE was detected at room temperature under optical pumping. Short wave UV electroluminescence (λ max 340-350 nm) was measured for p-AlGaN/n-AlGaN structures having up to 38 mol% and 9 mol% of AIN in p-AlGaN carrier emitter layers and n-AlGaN light emitting layers, respectively.
Circular integrating detectors in photo and thermoacoustic tomography

Thermoacoustic computed tomography provides a novel and promising technology in medical imaging. It is based on the generation of acoustic waves inside tissues by stimulation with electromagnetic waves. Acoustic waves are measured outside the stimulated sample and converted into a three-dimensional (3D) image with high contrast and high resolution. Since optical fibres can be used to guide a laser beam on an arbitrary curve, it is possible to realize an experimental buildup in such a way that the acoustic pressure is measured over circles. The aim of this article is to present the mathematical theory when the acoustic pressure is measured over a stack of circles.
Signal Analysis by Generalized Hilbert Transforms on the Unit Sphere

In 1D signal processing local energy and phase can be determined by the analytic signal. Local energy, phase and orientation of 2D signals can be analyzed by the monogenic signal for all i(ntrinsic)1D signals in an rotational invariant way by the generalized Hilbert transform. In order to analyze both i1D and i2D signals in one framework the main idea of this contribution is to lift up 2D signals to the higher dimensional conformal space in which the original signal can be analyzed with more degrees of freedom by the generalized Hilbert transform on the unit sphere. An appropriate embedding of 2D signals on the unit sphere results in an extended feature space spanned by local energy, phase, orientation/direction and curvature. In contrast to classical differential geometry, local curvature can now be determined by the generalized Hilbert transform in monogenic scale space without any derivatives.
THE REGION OF THE OPEN CLUSTER BO 10.

UBVRI photoelectric photometry for 39 stars in and around the open cluster Bo 10 is presented. The cluster appears to be composed of 15 stars, all of them with spectral types earlier than B5, plus one supergiant star of mid-K type. Its members yield an average reddening of E(B-V) equals 0.35. The evolutionary deviation curve provides a distance of 3.6 plus or minus 0.2 kpc (distance modulus 12.8 plus or minus 0.1), with an age of about 7 million years. It may be one of the oldest groups in the Carina region, but according to its distance the association to the nearer Carina OB1 complex (approximately 2.6 kpc) appears uncertain. The remaining 23 nonmember stars are nearby; five B-type stars situated at a distance of about 1.6 kpc may form a small stellar group. The possible relation with the WR star HD 92809 is discussed.
Subarcsecond Mid-Infrared Imaging of Dust in the Bipolar Nebula Hen 3-401

We present high-resolution, nearly diffraction-limited narrow- and broadband mid-IR images of bipolar reflection nebula Hen 3-401. The deconvolved images yield a pixel-limited spatial resolution of 0. ″09, demonstrating the superior imaging quality of the Gemini telescope. The infrared image of Hen 3-401 consists of a prominent core region of size 1'' and extended emissions along the walls of the bipolar lobes. We find that the distribution of aromatic infrared band (AIB) emission is different from that of the continuum emission and that the star has undergone multiple ejection of the AIB emission feature carrier at the end stages of its evolution. From the observed temperature gradient in the core, we suggest that the core has a flared disk geometry.
Development of Compton radiography of inertial confinement fusion implosionsa)

An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60 to 200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The radiographs have a spatial and temporal resolution of ∼10 μm and ∼10 ps, respectively. A statistical accuracy of ∼0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D nonuniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.
A two-phase simple model to determine the timing and duration of R&D project tasks

The problem of determining the timing of risky R&D tasks (activities) and non-routine tasks is analysed through a simple non-linear mathematical programming model. The model ignores issues related to the flow of information gathered at each time point as a function of the amount of resources invested to this time point (see Lucas 1971, Management Science , 17 , 679-697, including his followers, and the literature on managerial economics for alternative approaches). The typical non-convex or non-concave structure of the objective function, which maximizes the expected discounted net value of the project, implies the possibility of multiple local optimal solutions. Forpracticalpurposes,theglobalsolution canbeidentified either by employing global optimization methods satisfying the K - T necessary conditions, i.e. Z (the gradient function of the objective function) 0, or by enumerating the objective value function for, at most, four basic solutions. An illustrative example indicates that solutions establishi.
Efficiency of optical sensing by a plasmonic photonic-crystal slab

A one-dimensional photonic crystal with termination by a noble metal film—a plasmonic photonic-crystal slab—is theoretically analysed for its optical response at the variation of the dielectric permittivity of an analyte. A sharp attenuation peak associated with a ‘noble metal-visualized’ Bloch surface wave is observed due to plasmon absorption in the metal. We investigate the sensing performance of the slab and show that it is tolerant to the variation of probing conditions and the slab's structural parameters. As a consequence, the considered sensor exhibits an enhanced sensitivity and good robustness in comparison with conventional surface-plasmon and Bloch surface wave sensors.
On Timoshenko's Beams Coefficient of Sensibility to Shear Effect

Classical beams theory usually neglect shear contribution to deformation. Timoshenko´s Beam Theory (TBT) corrects this negligence. This work is a step in the research to check accuracy of TBT in piezoactuators and in nano beams, particularly in Carbon nanotubes (CNT). Before immerse into the nanoscale problem, the superior limit of applicability of TBT must be investigated. This work introduces a proposition to the range of validation of TBT. A sensibility coefficient related to free vibratory beams is proposed, in terms of a ratio of deflected geometry to aspect ratio of the beams. Finite difference and Galerkin finite element were used to formulate the computational model. This approach was checked with experimental results to propose a top validation of TBT. Convergence in solution process was verified with precedent works. Results are related to symmetric dynamic bending of beams considering shear deformability and rotatory inertia, at small change of configuration. Timoshenko’s beam models show a displacement field greater than those obtained with Euler-Bernoulli Theory (EBT). The magnitude of the difference is of 6 to 34 % greater in TBT in relation to EBT, for tree kinds of boundary conditions, for the same beam geometry and load pattern.
A Variable-Speed Method for Improving Motion Characteristics of Cam-Follower Systems

A cam is often assumed to be operated at a constant speed in designing a cam-follower system. The motion characteristics of the follower are determined once the cam displacement curve is designed. The traditional design method for improving the motion characteristics is to find a new displacement curve which has better motion characteristics. This paper, however, presents an alternative approach by varying the speed of the cam to reduce the peak values of the follower output motion characteristics. Constraints and design criteria for selecting suitable cam speed trajectories are then developed. Finally, examples are given to illustrate the design procedure and also to show its feasibility.
Decay of a cut‐off low and contribution to stratosphere‐troposphere exchange

We present a case study of the decay of a cut‐off low over north‐west Europe in June 1996, to establish how the stratospheric air initially contained within it was transferred to the troposphere. Two mechanisms for stratosphere‐troposphere exchange are examined: direct convective erosion of the base of the low, and filamentation of the outer layers of the low along the flank of the polar jet stream. The approach taken relies on a combination of in‐situ ozone and humidity measurements by MOZAIC (Measurement of Ozone and water vapour by Airbus In‐service aircraft) aircraft and ozonesondes, and the European Centre for Medium‐Range Weather Forecasts analyses. MOZAIC ozone is used to choose two analyses eight days apart at the genesis (14 June 1996) and decay (22 June 1996) of the low which have a consistent ozone/potential‐vorticity relationship. Trajectories (both isentropic and three dimensional (3D)) between these two analyses reveal a consistent pattern; at the base of the low (310 K, 450 mb) all the trajectories attain tropospheric PV values whereas, at 320 K, those trajectories that leave the low experience a decrease in PV and those that do not leave the low retain their initial PV. We propose that air parcels leaving the low were stretched into thin filaments along the flank of the jet stream, which made them vulnerable to 3D mixing. A MOZAIC flight on 21 June 1996 provides direct evidence for this process.
Analysis of Coulomb and Johnsen-Rahbek electrostatic chuck performance in the presence of particles for extreme ultraviolet lithography

The successful implementation of extreme ultraviolet lithography (EUVL) requires the use of an electrostatic chuck to both support and flatten the mask during scanning exposure. The EUVL Mask Standard, SEMI P37, specifies the nonflatness of the mask frontside and backside, as well as the thickness variation, to be 30 to 100 nm peak-to-valley, dependent on the class of substrate. Thus, characterizing and predicting the capability of the electrostatic chuck to reduce mask nonflatness to meet these specifications are critical issues. In this research, the ability of such chucks to deal with the presence of particles trapped between the substrate and chuck is investigated. Analytical and finite element modeling are used to identify the forces needed to fully embed or deform a particle during electrostatic chucking. Simulation results (using an elastic analysis) show that the forces generated by both Coulomb and Johnsen-Rahbek chucks should be able to sufficiently deform, or flatten, particles that are nearly 1.0 µm in size.
GaN-based photonic crystal surface emitting lasers with central defects

The GaN-based photonic crystal surface emitting lasers (PCSELs) with different central defects were fabricated and investigated. The threshold energy densities increased from 3.23 to 3.51 mJ/cm2 when the central defect size increased. In addition, lasing wavelengths decreased from 400 nm to 390 nm due to the guided mode shifting phenomenon for the PCSEL cavities with larger central defects. The tendency of threshold gain and resonance wavelength for PCSELs with different central defects were calculated by the multiple scattering method and well matched to the experimental results.The GaN-based photonic crystal surface emitting lasers (PCSELs) with different central defects were fabricated and investigated. The threshold energy densities increased from 3.23 to 3.51 mJ/cm2 when the central defect size increased. In addition, lasing wavelengths decreased from 400 nm to 390 nm due to the guided mode shifting phenomenon for the PCSEL cavities with larger central defects. The tendency of threshold gain and resonance wavelength for PCSELs with different central defects were calculated by the multiple scattering method and well matched to the experimental results.
Compensation Based Displacement Measurement Using Objective Laser Speckles

Abstract Objective laser speckles can be observed as intensity pattern from free space propagation of coherent light that is diffracted from a technically rough surface. Utilizing this pattern allows for very localized non-contacting measurement of surface displacement as well as strain, and carries a high potential for miniaturization. Existing objective speckle techniques suffer from decorrelation effects, dramatically decreasing the performance of such measurement techniques. In this paper we present a compensation based displacement measurement scheme, where we keep the measured speckle pattern displacement close to zero by actively following the measuring objects movement in a feedback operation. This converts the image sensor into a zero-detector, what considerably improves the speckle pattern correlation over a significantly extended measurement range.