Miracle-dz/UniFAR-FTUs huggingface dataset:
Dual-band dual-polarized perforated microstrip antennas for SAR applications

For dual-band dual-polarized synthetic aperture radar (SAR) applications a compact low-profile design is investigated. The operating frequencies are in the L and C-bands, centered about 1.275 and 5.3 GHz, respectively. Since the C-band frequency is larger by a factor of four, its array elements and inter-element separations are smaller by the same ratio. Thus, to allow similar scan ranges for both bands, the L-band elements are selected as perforated patches to enable the placement of C-band elements within them. Stacked-patch configurations were used to meet the bandwidth requirements, especially in the L-band. The C-band element was designed numerically, but the perforated L-band one required final experimental optimization. Also, in the latter case of L-band, a balanced transmission line feed was used to minimize cross polarization. For the C-band elements, slot coupling was used and, to simplify the feed, symmetric parasitic slots were incorporated to minimize cross polarization. No vertical connections were utilized, and electromagnetic couplings resulted in a compact low-profile design, with an electrically and thermally symmetric geometry.
MULTI-BAND AND POLARIZATION INSENSITIVE METAMATERIAL ABSORBER

The design and realization of a multi-band and polariza- tion insensitive metamaterial absorber is presented. The structure with thickness 1.1mm consists of six close rings which distribute in two metallic layers separated by FR4 flber glass PCB substrates. Ex- perimental results show that over 93.3% absorption can be achieved in this metamaterial absorber at multiple frequency bands (more than two). Due to the rotational symmetric pattern of the metamaterial, the performance of the absorber is insensitive to the polarization of the incident waves, indicating the superiority of the structure in the application.
Finding New Common Proper-Motion Binaries by Data Mining

This paper presents new common proper-motion binaries detected by applying well-known statistical criteria over large subsets of the astrometric catalogs available on- line. All the pairs have been confirmed by checking the photographic plates and are not in- cluded in the Washington Double Star Catalog. An initial measurement of separation and position angle has been obtained for each pair.
Ancient Ceramic Analysis by Neutron Activation in Association with Multivariate Methods

We report a comparative study of two archaeological sites, Bela Vista and Serrano, located in the Araruama region of the state of Rio de Janeiro, in Brazil. The elemental geochemical compositions of the ceramics from both sites were determined by Instrumental Neutron Activation Analysis (INAA). A statistical treatment of the data, using cluster analysis and principal component analysis, indicates that there are no correlations between these sites.
Operational issues at high lower hybrid power density in JET: waveguide conditioning and arc detection

The power handling capability of the JET Lower Hybrid Current Drive (LHCD) system is examined using the long-term database. The limitations, in particular in H-mode plasmas, are discussed and the performance compared with other LHCD experiments using multijunctions as power dividers. Although the power density of 25 MW m−2 has been exceeded in L-mode and almost obtained in ELMy H-mode (on 1/6th of the antenna), it is concluded that the RF conditioning performed on JET does not allow us to exceed an electric field of ∼5.5 kV cm−1 which is generally not sufficient under the rather weak coupling conditions of the JET H-mode. Modelling of an arc occurring in a waveguide indicates that rather small variations of the reflected wave (amplitude and phase) may occur, rendering arc detection based on RF measurements difficult in some cases. The JET bolometry diagnostic with four chords viewing the antenna front is found to be an efficient tool to detect an arc. In L-mode plasmas, a very good correlation between the amplitude of the bolometry signals and the iron spectroscopic lines is found. In H-mode the arc detection is clearly more difficult with enhanced radiation during the ELM but is still possible when the bolometry signals are properly processed.
Photoacoustic microscopy of neovascularization in three-dimensional porous scaffolds in vivo

It is a challenge to non-invasively visualize in vivo the neovascularization in a three-dimensional (3D) scaffold with high spatial resolution and deep penetration depth. Here we used photoacoustic microscopy (PAM) to chronically monitor neovascularization in an inverse opal scaffold implanted in a mouse model for up to six weeks. The neovasculature was observed to develop gradually in the same mouse. These blood vessels not only grew on top of the implanted scaffold but also penetrated into the scaffold. The PAM system offered a lateral resolution of ~45 μm and a penetration depth of ~3 mm into the scaffold/tissue construct. By using the 3D PAM data, we further quantified the vessel area as a function of time.
Topology optimization of periodic microstructures with a penalization of highly localized buckling modes

The problem of determining highly localized buckling modes in perfectly periodic cellular microstructures of infinite extent is addressed. A double scale asymptotic technique is applied to the linearized stability problem for a periodic structure built from linearly elastic microstructures. The obtained stability condition for the microscale level is then used to establish a comparative analysis between different material distributions in the base cell subjected to the same strain field at the macroscale level. The idea is illustrated by some two‐dimensional finite element examples and used to design materials with optimal elastic properties that are less prone to localized instability in the form of local buckling modes at the scale of the microstructure. Copyright © 2002 John Wiley & Sons, Ltd.
Star clusters and single stellar populations

Abstract Star clusters are ideal laboratories to test the theory of stellar evolution and provide very tight constraints on the concept of single stellar poputions (SSPs). Observations show that some stars fail to conform to the theoretical evolutionary scenario applicable to single stars. These special objects, particularly blue stragglers, present a challenge to our current theory of stellar evolution. They may be very important in the context of the integrated spectral properties of clusters. Here, we review the construction of SSP models, both empirically using star clusters and theoretically based on binary-interaction theory.
Recovering image resolution in reconstructing digital off-axis holograms by Fresnel-transform method

The resolution of amplitude and phase reconstruction of images from digital holograms by the Fresnel transformation method is limited by the pixel width in the reconstructed image plane. The reconstruction pixel depends on distance, wavelength, and number of pixels in the hologram. The spatial frequencies, in the reconstructed image, are band limited by the size of the reconstruction pixel. Undersampling can occur, in the image plane, in the reconstructed amplitude and/or wrapped phase maps. Recovery of reconstructed undersampled spatial frequencies, is possible by the fictitious enlargement of the digital hologram. Correct profile reconstruction of a silicon microelectromechanical structure is demonstrated, applying the proposed method.
Response to Comment on "Clustering by Passing Messages Between Data Points"

Affinity propagation (AP) can be viewed as a generalization of the vertex substitution heuristic (VSH), whereby probabilistic exemplar substitutions are performed concurrently. Although results on small data sets (≤900 points) demonstrate that VSH is competitive with AP, we found VSH to be prohibitively slow for moderate-to-large problems, whereas AP was much faster and could achieve lower error.
Traveling‐Wave Antenna for Exciting Waves in a Cylindrical Anisotropic Plasma

Several variations of a newly proposed device for exciting ion cyclotron waves in a magnetoplasma are analyzed theoretically and numerically. The results of this analysis are compared with those of a similar analysis of a Stix coil. The new coupler is composed of a set of identical helical straps driven by a multiphase rf source and excites waves that vary azimuthally as ejmθ where m =±1, ±2,…. The analysis reveals that the new coupler offers the following advantages over the Stix coil: (i) a certain degree of control over radial variations of accelerating fields, (ii) a preferred direction of propagation, (iii) more energy coupled into propagating waves (for a given input current), (iv) maximum loading resistance at a higher plasma density, and (v) a slightly wider effective density range for propagating waves.
Measurements of velocity distributions in the wake of a circular cylinder at low Reynolds numbers

Velocity measurements were made in the flow field behind a circular cylinder at Reynolds numbers from 10 to 80 and results compared with existing numerical solutions. Takami & Keller's solution for the velocity distribution in the wake shows good agreement at low Reynolds numbers and fair agreement at high Reynolds numbers. The drag coefficient of the cylinder and the size of the standing eddies behind the cylinder were also determined. They are compatible with existing experimental and numerical results. Details of the velocity distribution in the standing eddies are clarified.
Droplet migration, deformation, and orientation in the presence of a plane wall: A numerical study compared with analytical theories

The motion of a deformable drop in linear unidirectional shear flow close to a fixed wall is considered using a boundary integral technique for Stokes flow. This problem is solved numerically to circumvent the limitations of existing analytical models, especially in the region near the wall. The lateral and longitudinal disturbance velocities of the particle were calculated and compared with analytical approximations. Although analytical theories give reasonable predictions, large deviations occur at small wall distances and large particle deformations. This is mainly due to the fact that the altered orientation and deformation of the particle, arising from the presence of a wall, is disregarded in all analytical models.
Global Linear Instability

This article reviews linear instability analysis of flows over or through complex two-dimensional (2D) and 3D geometries. In the three decades since it first appeared in the literature, global instability analysis, based on the solution of the multidimensional eigenvalue and/or initial value problem, is continuously broadening both in scope and in depth. To date it has dealt successfully with a wide range of applications arising in aerospace engineering, physiological flows, food processing, and nuclear-reactor safety. In recent years, nonmodal analysis has complemented the more traditional modal approach and increased knowledge of flow instability physics. Recent highlights delivered by the application of either modal or nonmodal global analysis are briefly discussed. A conscious effort is made to demystify both the tools currently utilized and the jargon employed to describe them, demonstrating the simplicity of the analysis. Hopefully this will provide new impulses for the creation of next-generation algorithms capable of coping with the main open research areas in which step-change progress can be expected by the application of the theory: instability analysis of fully inhomogeneous, 3D flows and control thereof.
Charging effects in silicon nanocrystals within SiO2 layers, fabricated by chemical vapor deposition, oxidation, and annealing

Metal–insulator–semiconductor structures with a layer of silicon nanocrystals embedded within the SiO2 layer at a tunneling distance from a p-type silicon substrate and fabricated using chemical vapor deposition, oxidation, and annealing, exhibited charge trapping, determined from the capacitance–voltage (C–V) characteristics, which abruptly increased at fields above 2.5 MV/cm. Electrons or holes are trapped when biasing the structure into inversion or accumulation, respectively, and retention of trapped charge is demonstrated. The I–V characteristics exhibit an N-shaped form, indicating screening effects due to charging; an initial current spike, attributed to transient charging of nanocrystals, occurs at the same voltage causing abrupt C–V shift increase, with Fowler–Nordheim current rising at higher voltages. These structures are promising for memory device applications.
Bayesian Methods for Censored Categorical Data

Abstract Bayesian methods are given for finite-category sampling when some of the observations suffer missing category distinctions. Dickey's (1983) generalization of the Dirichlet family of prior distributions is found to be closed under such censored sampling. The posterior moments and predictive probabilities are proportional to ratios of B. C. Carlson's multiple hypergeometric functions. Closed-form expressions are developed for the case of nested reported sets, when Bayesian estimates can be computed easily from relative frequencies. Effective computational methods are also given in the general case. An example involving surveys of death-penalty attitudes is used throughout to illustrate the theory. A simple special case of categorical missing data is a two-way contingency table with cross-classified count data xij (i = 1, …, r; j = 1, …, c), together with supplementary trials counted only in the margin distinguishing the rows, yi (i = 1, …, r). There could also be further supplementary trials report.
Structure formation in bidisperse sedimentation

It is known that when two different species of small particles with radii in the range 10–100 μm are dispersed uniformly in fluid and are settling under gravity, there may be a tendency for the particles of each species to gather together and develop a bulk vertical streaming motion, which results in much larger magnitudes of the mean velocity of at least one of the two types of particle. After a review of the published data on such streaming motions we describe new visual and photographic observations of the evolution of the internal structures (which are sometimes more globular than columnar) in a large number of different bidisperse systems. It appears that the observed structures result from instability of the statistically homogeneous dispersion to small concentration disturbances for certain combinations of values of the ratios of the sizes and densities of the two types of particle and the volume fractions of the two species. The condition for growth of a sinusoidal disturbance of the homogeneous dispersion is derived from the two particle-conservation equations and is found to involve the dependence of the two mean particle velocities on the two particle concentrations in a homogeneous dispersion. Previously calculated values of these mean velocities for a dilute dispersion suggest that the condition for instability is indeed satisfied for not-too-small particle concentrations and certain combinations of the size and density ratios of the two particle species. The results of the instability theory are generally consistent with the observed features of the structures, regarded as finite-amplitude forms of the small disturbances with maximum growth rate.
MASS SCALE IN THE SINE–GORDON MODEL AND ITS REDUCTIONS

Known Bethe ansatz results about the sine–Gordon factorized scattering are reinterpreted in terms of perturbed conformal field theory. We obtain an exact relation between the ultraviolet and asymptotic scales (i.e. between the dimensional coupling constant and the soliton mass) and an explicit expression for the vacuum energy. The reduction technique then permits one to relate exactly the coupling constants and the mass scales in the Φ13-perturbed minimal CFT models. The preasymptotically free situation at β2 near 8π is discussed on a preliminary footing.
Evidence for Langmuir wave collapse in the interplanetary plasma

With the Fast Envelope Sampler part of the URAP experiment on Ulysses, we have observed much rapidly varying structure in plasma waves in the solar wind. Here we discuss extremely narrow (1 ms) structures observed together with electrostatic Langmuir waves, as well as some broader Langmuir wave packets
Educational Multimedia Databases

Windows Toolkit An Application Programming Interface for Java that allows Java programs to manipulate objects in a graphical windowing environment. Active Server Pages A script language developed by Microsoft that allows a HTML page to contain active code that is executed by the web server whenever the page is requested. This is a form of Server-Side Scripting. ADSR Attack, Decay, Sustain, Release: four phases of the amplitude of an audio signal that together describe the “envelope”. Of these four phases, the duration and the “steepness” is specified. API Application Programming Interface: the computer language interface of a software component to other software components; so an API specifies how a software component should interact with another on the level of a programming language.
Sensitivity studies for atmospheric carbon dioxide retrieval from atmospheric infrared sounder observations

Abstract The atmospheric infrared sounder (AIRS) exhibits great potential for providing atmospheric observation data for long-term regional and global carbon-cycle studies, which are essential for understanding the uncertainty of climate change. The sensitivity of global atmospheric CO 2 retrieval from the AIRS observations by quantifying errors related to CO 2 measurements in the infrared spectrum is investigated. A line-by-line radiative transfer model is used to evaluate the effects of atmospheric temperature profile, water vapor profile, and ozone ( O 3 ) data on the accuracy of CO 2 measurements under five standard atmospheric models. The analytical results indicate that temperature, water vapor, and O 3 are important factors, which have great influences on the sensitivity of atmospheric CO 2 retrieval from the AIRS observations. The water vapor is the most important factor in the tropics, whereas the temperature represents major interference for multitude and subarctic regions. The results imply that precise measurements of temperature, water vapor, and O 3 can improve the quality of atmospheric CO 2 data retrieved from the AIRS observations.
Differential mixing in a stratified fluid

We present an experimental and theoretical study of the effects of localized mixing on a stratified fluid contained in a reservoir. In the experiments, mixing is accomplished by means of a vertically oscillating, horizontal grid located near the water surface at one end of the reservoir. Once the grid is set in motion, a mixed layer forms immediately beneath it. As this layer deepens, a horizontal pressure gradient builds up which drives an outflow of mixed fluid into the unmixed interior of the reservoir. This outflow slows, and eventually brings to a halt, mixed-layer deepening under the grid. At this equilibrium depth, the vertical velocity of the entrainment interface induced by the outflow exactly equals the velocity at which the entrainment interface would move downwards because of mixing. This equilibrium state persists until the outflow intrusion is blocked by the far wall of the reservoir, at which time deepening resumes under the grid. Asymptotically, the fluid reaches a state in which mixed-layer deepening is independent of position.
Algorithm for factor analysis in inversive space.

The aim of this research was to determine possibilities of latent dimension explication in inversive space which is usually completely ignored as a systematic and different mistake. Research design was made for PC by Borland Delphi developing tool. For the needs of this research and example, data for students described by 14 morphological variables have been processed. The results have shown that inversive space defined this way is not chaotic and that it possesses real existence which was possible to recognize and comprehend, and therefore credibly explain. Restrictions of models and algorithms only exist in the situation when inversion matrices of initial data are not Gramian, and this procedure is even possible in positive self-definite matrices. Practical implications of this research are more than explicit since they enable more detailed research on phenomena which were until now trapped in the space of unknown without possibilities of scientific clarification. Original way of research is indisputable, because there are simply no similar algorithms.
Is the t Test Really Conservative When the Parent Distribution is Long-Tailed?

Abstract It is generally believed that the t test is conservative for a sample from a long-tailed symmetric distribution. Yet the probability inequalities expressing this property have not been proved. The inequalities are explored here using various criteria for long-tailedness and leaning on the geometrical interpretation of the t test. It is proved that the t test is conservative but only for large enough critical values. Examples of a liberal t test for lower values are given. The results are used to explain some curiosities in the asymptotic distribution of the t statistic and to study its behavior when the parent distribution is skewed.
Interference patterns in solar radio spectra: high-resolution structural analysis of the corona

Aims. We present a new method for high-resolution structural analysis of the solar corona. Methods. The relationship between the spectral features of various types of solar radio bursts and the physical properties of their sources have been extensively studied by many authors. On the other hand, it is plausible to accept that the spectral properties of the solar radio radiation received on the Earth are – besides the physics of the radio source – influenced by an inter-laying medium that radio waves propagate through. In particular, the regular structures in the solar corona – such as coronal waves, oscillations in shock fronts, the fine structures of coronal loops, streamer current sheets, etc. – might efficiently filter transferred radio radiation just as (broad-band) X-rays are filtered by a periodic atomic structure of crystals; the difference is only in the spatial scale. Using the wave optics methods, we investigate the prospective influence of considered coronal structures on the propagating radio waves originating in an external remote source. Results. Preliminary results have shown that the resulting modelled radio emission may recall the spectra of observed zebra patterns for the simple 1D density structure considered here and for a reasonable set of parameters. Conversely, it is suggested that the spectra of the zebra patterns might be used for an analysis of those coronal structures that made these traces on the radiation by methods similar to those used in crystallography. The possibility of the presence of such regular small scale structures in the solar corona is demonstrated. For completeness, a brief review of contemporary models of the zebra patterns is provided.