Miracle-dz/UniFAR-FTUs huggingface dataset:
Dynamic Forcing of the Slow Transients by Synoptic-Scale Eddies: An Observational Study.

Abstract The interactions between low-frequency transients and synoptic-scale eddies are examined. The 300-mb data from 1981 to 1986 analyzed by the ECMWF are used to calculate the height tendency of the slow transients due to vorticity forcing by synoptic-scale eddies. It is found that the low-frequency transients are correlated with the forcing by the synoptic-scale eddies, most notably in the eastern part of the Pacific and Atlantic basins, where a significant portion of the time variance of the slow transient height field can be explained by the forcing. The lag correlation coefficients between the forcing and the slow transients indicate that the former leads the latter by a small phase difference (about one day). The structure of the forcing is studied by an EOF analysis. The leading EOF mode in both oceanic sectors has a dipole structure. The pattern of the geopotential height field associated with each EOF mode of the forcing is also identified. The height pattern associated with the first Pacific.
Radiation from a slot in an impedance surface

The effects of a lossy-ground plane on the radiation from a slot are analyzed by using a Green's function of an impedance surface. Numerical results of the radiation field, radiated power, and loss power are presented for various lossy ground planes. In particular, the radiation field and the radiated power from a short slot are given by simple closed expressions. The analytical model of a slot in an impedance surface is validated by radiation field measurements.
Elastic Response of a Simple Amorphous Binary Alloy Near the Glass Transition

The elastic constants of an amorphous binary soft sphere alloy have been determined by molecular-dynamics simulations. The shear modulus of the amorphous solid is found to vanish at the glass transition temperature, below which it is significantly smaller than the value found for a polycrystalline sample under the same density-temperature conditions.
IMF orientation, solar wind velocity, and Pc 3‐4 signals: A joint distribution

Separate studies using the same micropulsation data base in the period range 10–150 s have shown earlier that signal levels recorded during September, October, and November 1969 at Calgary correlated positively with both solar wind alignment of the IMF and solar wind speed, but each correlation contained enough scatter to allow for influence of the other factor. In this report, joint correlations of velocity and field direction with parameters representing hourly distributions rather than minima of IMF orientation angle display the relative effect of the two agents on magnetic pulsation signal levels. The joint correlations reduce the overall scatter and show that solar wind speeds above 200–300 km/s and angles between the IMF and the sun-earth line of less than 50°–60° are associated with enlarged magnetic pulsation amplitudes. These threshold effects tend to support both the bow shock origin and the Kelvin-Helmholtz amplification of daytime signal transients in the Pc 3, 4 period ranges.
Dispersion driven instability in miscible displacement in porous media

The effect of dispersion on the stability of miscible displacement in rectilinear porous media is examined. Following a convection–dispersion (CDE) formalism, the base state of Tan and Homsy [Phys. Fluids 29, 3549 (1986)] at conditions of unfavorable mobility contrast is analyzed. Emphasis is placed on the dependence of the dispersion coefficient on flow rate (e.g., mechanical dispersion). It is found that such a dependence induces a destabilizing contribution at short wavelengths. This effect, which is in contrast to the stabilization commonly associated with dispersion, is highly pronounced near the onset of the displacement. It is also near this onset that, for a certain condition, the cutoff wavenumber becomes infinitely large. An analytical expression is derived for this condition and the origin and implications of the instability are discussed. It is also suggested that the present CDE formulation may be inadequate in providing stability criteria for a range of unstable flows.
Understanding the kinematics of Galactic Centre gas

A coherent picture is constructed on the Galaxy's H I, CO and CS emissions in the region |l| ≤ 10°, |b| ≤ 0.5°. The flow of gas at the Galactic Centre is dominated by a bar that has corotation at r = 2.4 ± 0.5 kpc, which we view at an angle of 16 ± 2° from its major axis. The first CO emission arises where gas is obliged to switch from x 1 orbits to x 2 orbits in the notation of Contopoulos. This gives rise to a shock and a clear signature in the (l, v) diagram. The great Galactic Centre molecular clouds such as Sgr B are on x 2 orbits.
A study of the dispersion of the electron distribution in the presence of E and B gradients: Application to electron heating at quasi-perpendicular shocks

The dynamics of electrons in the presence of E and B field gradients is considered. The results are applied to electron heating in quasi-perpendicular shocks. The main focus is on the transitions between adiabatic and overadiabatic heating and from perpendicular to oblique geometry. Contrary to previous results, it is shown that the divergence of initially close electron trajectories always takes place in the quasi-perpendicular collisionless shock front. In the case of negligible electric field gradients at the shock front, the divergence rate depends only upon the magnetic field gradient and results in adiabatic heating. If the electric field gradient is not negligible, divergence rate depends on increasing electric field gradients. In this case, the divergence rate in the first part of the ramp will exceed the “adiabatic” divergence rate. This enhancement is significant for scales of the electric field of about 4–6 c/ωpe. Under the conditions of the Earth's bow shock the magnetic field and particularly its gradients affect the electron trajectory divergence rate and thus the process of thermalization of electrons.
Complexity penalized least squares estimators: Analytical results

A simple variational approach to the estimation of timeseries is studied in detail and mathematical rigor. The functional in question is a complexity penalized sum of squares. The results include existence and uniqueness of the statistical estimate, as well as continuous dependence and stability in dependence on parameters and data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cylindrical and spherical ion acoustic waves in a plasma with nonthermal electrons and warm ions

Using the reductive perturbation technique, nonlinear cylindrical and spherical Korteweg–de Vries (KdV) and modified KdV equations are derived for ion acoustic waves in an unmagnetized plasma consisting of warm adiabatic ions and nonthermal electrons. The effects of nonthermally distributed electrons on cylindrical and spherical ion acoustic waves are investigated. It is found that the nonthermality has a very significant effect on the nature of ion acoustic waves.
Scattering by Spherically Symmetric Inhomogeneities

The Jost‐function formulation of quantum scattering theory is applied to classical problems involving the scattering of a scalar plane wave by a medium in which the velocity is a function only of the spherical radial coordinate. This technique is used to solve the radial differential equation for scattering from a constant spherical inhomogeneity. The radial equation can be converted into an integral equation incorporating the Jost boundary conditions. The l−0 partial‐wave integral equation for a constant inhomogeneity is solved using an iteration procedure (the first two iterations are considered). The Jost function and l−0 cross section σ0 are plotted as a function of kR1, where k is the wavenumber in the surrounding medium and R1 is the sphere radius. The iterative technique is good for long wavelengths (kR1≪1) and any ratio of wavenumbers in the scattering and surrounding media. For shorter wavelengths and small ratio of wavenumbers (e.g., k1/k = 1.1, where k1 is the wavenumber in the scattering mediu.
A relation between dynamics of coronal mass ejections and production of solar energetic particles

During January 1997-June 1998, the Large Angle Spectroscopic Coronagraph (LASCO) aboard the Solar and Heliospheric Observatory spacecraft (SOHO) registered 670 coronal mass ejections (CMEs). We compare two groups of the 300-800 km s -1 CMEs: (i) (very) gradually accelerating CMEs with acceleration below $10 {\rm m} {\rm s}^{-2}$, and (ii) impulsively accelerating CMEs with acceleration $a> 20 {\rm m s}^{-2}$ near the Sun, continuing then with the constant speed across the LASCO field of view. An association of those CMEs with solar energetic particle (SEP) events is studied using the data of the energetic particle experiment ERNE also aboard SOHO. There were no SEP events registered in association with the first group CMEs, whereas about 8% of the second group CMEs produced an enhancement in the ~10 MeV proton flux at SOHO. This result along with a number of additional tests supports an idea that production of SEPs by the moderate speed CMEs depends not only on the final speed but also on the magnitude of acceleration that CME experiences during its liftoff. The SEP-producing CMEs are typified by impulsively accelerating CMEs accompanied by soft X-ray flares and coronal shocks.
Quasinormal modes of Schwarzschild anti-de Sitter black holes: Electromagnetic and gravitational perturbations

We study the quasinormal modes (QNM) of electromagnetic and gravitational perturbations of a Schwarzschild black hole in an asymptotically anti\char21{}de Sitter (AdS) spacetime. Some of the electromagnetic modes do not oscillate; they only decay, since they have pure imaginary frequencies. The gravitational modes show peculiar features: the odd and even gravitational perturbations no longer have the same characteristic quasinormal frequencies. There is a special mode for odd perturbations whose behavior differs completely from the usual one in scalar and electromagnetic perturbations in AdS spacetime, but has a similar behavior to the Schwarzschild black hole in an asymptotically flat spacetime: the imaginary part of the frequency goes as ${1/r}_{+},$ where ${r}_{+}$ is the horizon radius. We also investigate the small black-hole limit showing that the imaginary part of the frequency goes as ${r}_{+}^{2}. $ These results are important to the AdS/CFT conjecture since, according to it, the QNM's describe the approach to equilibrium in the conformal field theory.
Method for Measurement of Speech Identification

A new method for measuring speech‐identification behavior is described. Thirty closed‐message sets were constructed. Each set contained 10 synthetic sentences, representing 4 levels of approximation to a “real” sentence. Sentence length and informational content were controlled. Message identification under conditions of low‐pass filtering and periodic interruption was studied in 30 subjects. Performance varied systematically with informational content. Articulation functions under normal and degraded conditions are compared with analogous functions for more conventional‐speech audiometric materials. [This investigation was supported by National Institute of Neurological Diseases and Blindness, National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare. ]
Avalanche photodiode punch-through gain determination through excess noise analysis

A new approach to determine the multiplication gain at punch-through for an avalanche photodiode with separate absorption and multiplication regions from excess noise measurement is discussed. Correctly determining the gain at punch-through is crucial for characterizing performance parameters of this type of avalanche photodiode. In order to illustrate the viability of this technique, in this work, a Ge on Si avalanche photodiode is analyzed. At a punch-through bias of 15 V, the multiplication gain was determined to be ∼1.54 while a simulation based on the device structure yielded a punch-through gain of 1.65.
Why do few high-redshift QSO narrow-line absorption systems exhibit mixed ionization spectra?

Although few high-redshift QSO narrow-line absorption systems show evidence of ''mixed'' ionization, we suggest that physical conditions in the gas containing moderately and highly ionized systems are basically similar to those in the ''hot'' galactic interstellar gas. We argue that the paucity of systems with absorption due to lowly ionized species is related to the absence of a cloud phase under the physical conditions appropriate to young galaxies. we point out that Wolfe's observations showing that lowly ionized species become less prevalent at higher redshifts are not inconsistent with the view that the properties of the interstellar media in the haloes of intervening galaxies are determined by the same processes which control the properties of the halo gas in our own Galaxy.
On the Restricted Size Ramsey Number Involving a Path P3

Abstract For any pair of graphs G and H, both the size Ramsey number ̂r(G,H) and the restricted size Ramsey number r*(G,H) are bounded above by the size of the complete graph with order equals to the Ramsey number r(G,H), and bounded below by e(G) + e(H) − 1. Moreover, trivially, ̂r(G,H) ≤ r*(G,H). When introducing the size Ramsey number for graph, Erdős et al. (1978) asked two questions; (1) Do there exist graphs G and H such that ˆr(G,H) attains the upper bound? and (2) Do there exist graphs G and H such that ̂r(G,H) is significantly less than the upper bound? In this paper we consider the restricted size Ramsey number r*(G,H). We answer both questions above for r*(G,H) when G = P3 and H is a connected graph.
Properties of cometary dust from color and polarization

Abstract It is shown that the maximum value of the polarization of light scattered by either spherical or spheroidal polydisperse particles is mainly governed by the composition of grain material (complex refractive index), whereas its color is mainly determined by the grain size distribution. This conclusion is also valid for particles of a more general shape. Relations are obtained which make it possible to evaluate the properties of cometary grains from the color and polarization measured for the cometary continuum at large phase angles. These relations are especially suitable for carrying out a comparative analysis of cometary dust. From our own photometric and polarimetric data of five recent comets we predict their dust properties and compare them with the interpretation of infrared observations available in the literature.
Comments on “Magnetic Field Gradients and Their Uses in the Study of the Earth's Magnetic Field” by Harrison and Southam

HARRISON and SOUTHAM (1991) point out the many benefits of magnetic gradiometry including the enhancement of short-wavelength (nearby) anomalies relative to long-wavelength (far away) anomalies, and the heavy attenuation of diurnal or magnetic storm variations usually present in total-field measurements. In addition, they point out that gradient profiles, like field component profiles, can be used to test for anomaly linearity and strike angle. HARRISON and SOUTHAM (1991) propose using a SQUID gradiometer to measure the gradient tensor components due to crustal sources and suggest that SQUID gradiometers can be made sensitive enough to measure sea-floor spreading anomalies from orbiting satellites.We believe that all of the benefits attributed to tensor gradiometry can be obtained with total-field gradiometry as well. First we will describe the capabilities of existing gradiometer systems, then we will describe how they can be used to obtain the same information as SQUID gradiometers.
Heat Transfer Enhancement and Entropy Generation in a Square Enclosure in the Presence of Adiabatic and Isothermal Blocks

In the present work, heat transfer and entropy generation characteristics are numerically investigated in presence of single and double obstructive blocks within a square enclosure. It is found that the adiabatic block(s) enhance(s) the heat transfer marginally up to a critical size in a convection-dominated regime. On the other hand, the enhancement parameter is observed to be more with an increase in block size in a lower range of Rayleigh numbers for an isothermal block. The entropy generation for thermal irreversibility is observed to be several orders higher than that due to viscous dissipation in all cases.
Spectrum of doubly ionised indium

The emission spectrum of indium has been photographed over the spectral range from 340 to 6500 AA using a disruptive electrodeless discharge and a spark in helium as sources. The analysis of In III has been revised and extended and now includes 4d10ns (n=5 to 12), 4d10np (n=5 to 9), 4d10nd (n=5 to 9) and 4d10nf (n=4 to 7). Polarisation theory has been applied to the 4d10ng (n=5 to 9) and 4d10nh (n=6 to 9) series and the ionisation potential deduced to be 226191 cm-1. The dipole polarisability of the 4d10 core is estimated to be 3.45 a03. Most of the expected terms of 4d95s5p are established for the first time.
Invariance of deficiency indices under perturbation for discrete Hamiltonian systems

This paper deals with discrete Hamiltonian systems with one singular endpoint. Using Hermitian linear relation generalized by linear Hamiltonian system, the invariance of the minimal and maximal deficiency indices under bounded perturbation for discrete Hamiltonian systems is built. This parallels the well-known results for linear Hamiltonian differential systems obtained by F.V. Atkinson.
The radio properties of cD galaxies in Abell clusters. I - An X-ray selected sample

The radio and X-ray properties of a sample of 27 cD galaxies in rich clusters are presented. The radio data consist of 6 cm VLA maps at a resolution of 1-2 arcsec. The X-ray data consist of images and surface-brightness profiles from the Einstein IPC and derived quantities such as cooling times, mass-accretion rates, and thermal pressures from Arnaud (1988). These data are used to explore the relationship between X-ray cooling cores, and the power and morphology of the radio emission. It is found that 71 percent of the cD's with X-ray cooling cores are radio loud, whereas a smaller but still significant 23 percent of cD's without cooling cores are detected at 6 cm above 0.2 mJy. Among the radio galaxies in noncooling core clusters are luminous and extended wide-angle tails. There is a weak correlation between the mass-accretion rate and the radio power for cD's. There is also an interesting class of cooling core cluster (e.g., A2052) with small diameter, amorphous radio emission that may be the result of diffusion along radial magnetic fields set up in cooling inflows. Finally, the relationships between optical emission-line luminosity with radio power and mass-accretion rate are examined. 74 refs.
A newly developed UHF radiotelescope for interplanetary scintillation observations: Solar Wind Imaging Facility

A large‐aperture radiotelescope called the Solar Wind Imaging Facility (SWIFT) has been developed at the Toyokawa Observatory of the Solar‐Terrestrial Environment Laboratory (STEL), Nagoya University. The SWIFT is dedicated to interplanetary scintillation (IPS) observations of the solar wind at 327 MHz, the same frequency as that of the existing STEL IPS system. The aim of this instrument is to improve the spatial and temporal resolutions of tomographic reconstructions from STEL IPS observations by increasing the number of usable lines of sight within a given time period. The SWIFT consists of a pair of asymmetric cylindrical parabolic reflector antennas with an aperture size of 108 m (N‐S) by 19 m (E‐W), and a 192‐element phased array receiver system which forms a single beam steerable between 60°S and 30°N with respect to the zenith. Since the antenna beam is fixed in the local meridian, IPS observations are taken around the time of meridian transit for each source. The performance of the SWIFT has been tested using preliminary observations for strong discrete sources and diffuse galactic background.
New Fe-metalloids based nanocrystalline alloys with high Bs of 1.9T and excellent magnetic softness

The melt-spun Fe83.3–84.3Si4B8P3–4Cu0.7 alloys have a heterogeneous amorphous structure including a large amount of α‐Fe-like clusters. Compared with the FeSiB alloys, the particle size rapidly decreases from several hundred nanometers to 2–3nm due to the proper amounts of simultaneous P and Cu additions. By controlling the crystallization process, a homogeneous nanocrystalline structure composed by small α‐Fe grains with size of 10–17nm in diameter can be realized from the heterogeneous amorphous alloys. The nanocrystallized Fe83.3–84.3Si4B8P3–4Cu0.7 alloys show the extremely high saturation magnetic flux density of 1.88–1.94T sufficiently near to 1.97T of Fe‐3.5mass%Si crystalline soft magnetic alloys, and exhibit low coercivity of less than 10A∕m and higher effective permeability of 16 000–25 000 at 1kHz due to the simultaneous realization of the homogeneous nanocrystalline structure and the small magnetostriction of (2–3)×10−6. In addition, the nanocrystalline alloys exhibit the superior core loss to .
An Algorithm for Tracking Eyes of Tropical Cyclones

Abstract A tropical cyclone (TC) eye tracking (TCET) algorithm is presented in this study to objectively identify and track the eye and center of a tropical cyclone using radar reflectivity data. Twelve typhoon cases were studied for evaluating the TCET algorithm. Results show that the TCET can track TC centers for several hours. The longest tracking time is about 35 h. Eye locations estimated from different radars showed consistency with a mean distance bias of about 3.5 km and a standard deviation of about 1.5 km. The TCET analysis shows decreasing eye radius as TCs approach land, especially within 50 km of the coastline. The TCET algorithm is computationally efficient and can be automated by using the TC center in the previous volume or the estimated center from satellite images as an initial guess. The TCET may not accurately find the TC center when a TC is weak or does not have an enclosed eyewall or when it does have highly noncircular eyes. However, the algorithm is still suitable for operational i.
Polarization-resolved nonlinear dynamics in long-wavelength single-mode VCSELs subject to orthogonal optical injection

In this work we perform an experimental study of the polarization-resolved nonlinear dynamics of a 1550 nm single-mode linearly polarized VCSEL when subject to orthogonal optical injection. We have measured the stability maps that identify the boundaries between regions of different nonlinear dynamics by using the RF-spectrum of the total power. These maps are measured in the plane of the frequency detuning between the injected light and the orthogonal linear polarization of the VCSEL versus injected power. Stability maps are obtained for two different values of the bias current. Analysis of the dynamics is given in terms of the time traces of the total power and of both linearly polarized output signals. The corresponding RF and optical spectra are also measured. Different dynamical regimes including periodic, period doubling, and irregular dynamics are observed for both polarizations. When the frequency detuning is positive polarization switching can be observed in a periodic dynamical regime, including both period one and period two behaviours. For positive frequency detuning, the only polarization that contributes to the dynamics of the total power is the orthogonal polarization. For negative frequency detuning values both linear polarizations contribute to the dynamics of the total power.