Miracle-dz/UniFAR-FTUs huggingface dataset:
Charge density waves in d-wave superconductors

A self-consistent theory of charge density waves in partially dielectrically gapped superconductors with d-pairing is proposed. The dependences of the dielectric (Σ) and superconducting (Δ) order parameters on the temperature and other parameters of the problem is examined. The corresponding angular diagrams for the gap distribution over the Fermi surface are constructed for the first time. The theory is used to explain the properties of high-temperature oxides. The effect of the displacement angle between the lobes of the order parameters Σ and Δ on the gap distribution in momentum space and on the reentrance phenomenon for Σ with respect to temperature is analyzed.A self-consistent theory of charge density waves in partially dielectrically gapped superconductors with d-pairing is proposed. The dependences of the dielectric (Σ) and superconducting (Δ) order parameters on the temperature and other parameters of the problem is examined. The corresponding angular diagrams for the gap distribution over the Fermi surface are constructed for the first time. The theory is used to explain the properties of high-temperature oxides. The effect of the displacement angle between the lobes of the order parameters Σ and Δ on the gap distribution in momentum space and on the reentrance phenomenon for Σ with respect to temperature is analyzed.
Triangle groups and PSL2(q)

Abstract We consider hyperbolic triangle groups of the form T = T p 1, p 2, p 3 , where p 1, p 2, p 3 are prime numbers. Let p be a prime number and n be a positive integer. We give a necessary and sufficient condition for L 2(pn ) to be the image of a given hyperbolic triangle group, where L 2(pn ) denotes the projective special linear group PSL2(pn ). It follows that, given a prime number p, there exists a unique positive integer n such that L 2(pn ) is the image of a given hyperbolic triangle group. Finally, given a hyperbolic triangle group T, we determine the asymptotic probability that a randomly chosen homomorphism φ : T → L 2(pn ) is surjective, as pn tends to infinity.
Tidal Friction in the Irish Sea

The dissipation of energy in the tides has recently formed the subject of a paper by Mr. R. O. Street. In that paper it is assumed that the energy is dissipated by the viscous drag of layers of water which move parallel to the bottom of the sea. The assumption that tidal currents move in laminar motion is so opposed to ordinary observation of the surface of the sea in a tideway that I felt certain, on reading the paper, that if some other method could be found, which did not depend on any special assumptions as to the nature of the motion, it would be found that Mr. Street’s estimate of the dissipation is very much too small. This view is strengthened by the consideration that Reynolds criterion of stability would lead us to expect that eddies would form in any stream of sea-water flowing at a speed of 1 knot or more, when the depth is greater than some quantity of the order of magnitude of 1 or 2 cm. Since the mean depth of the Irish Sea is over 40 fathoms, mathematical considerations alone would lead us to suspect the existence of the eddies, which can in fact he seen marking the surface of the sea in places where the current runs exceptionally strongly, or over a particularly uneven bottom. Several of these places are marked as “ripples” on the chart of the Irish Sea, the sheet of water to which Mr. Street applied his calculations.
Rigorous 3D error analysis of kinematic scanning LIDAR systems

Abstract To date, LIDAR sensors have been primarily airborne, and utilized as a fast and efficient means of collecting topographic information. As a result, in research studies and in most commercial work the accuracy of the LIDAR information is primarily obtained by examining the vertical component of LIDAR error only. However, more and more end users are using LIDAR intensity to produce planimetric feature maps, and there are also emerging ground based kinematic laser scanning systems which are mounted on a van or truck platform. For both of these uses, the traditional vertical only error analysis of the LIDAR system is inadequate when defining the overall expected accuracy of the end-product received from the system. Therefore, in order to quantify the overall 3D expected accuracy of LIDAR systems (both land and air based) a rigorous 1st order error analysis of the LIDAR georeferencing equations are undertaken. Typical error parameters are then placed into the error analysis to generate expected horizontal and vertical system accuracies for different LIDAR system configurations. Finally, the results obtained from the theoretical error analysis are independently verified using real world LIDAR data.
A Large Deviation Principle in Holder Norm for Multiple Fractional Integrals

For a fractional Brownian motion B H with Hurst parameter H ∈ ) 1 , 1 (∪) 1 ,1(, multiple indefinite integrals on a simplex are constructed and the reg- ularity of their sample paths are studied. Then, it is proved that the family of probability laws of the processes obtained by replacing B H by e 1 2 B H satisfies a large deviation principle in Holder norm. The definition of the multiple integrals relies upon a representation of the fractional Brownian motion in terms of a stochas- tic integral with respect to a standard Brownian motion. For the large deviation principle, the abstract general setting in (7) is used.
The Impact of Seasat-A Scatterometer Data on High-Resolution Analyses and Forecasts: The Development of the QE II Storm

Abstract In this paper the impact of Seasat scatterometer winds in numerical weather prediction (NWP) is discussed with the help of the results of some cases studied. The development of the Queen Elizabeth II (QE II) storm from 1200 UTC 9 September to 0000 UTC 11 September 1978 is analyzed and forecast with a high-resolution (60-km) limited-area model (LAM). Parallel assimilation and forecasts are performed; in the SCAT run, Seasat scatterometer winds were used, but from the parallel NOSCAT run these winds were omitted. The NOSCAT analyses catch the development of the QE II storm better than any other operational numerical weather prediction model did, to our knowledge. When Seasat surface winds were included, the wind and sea level pressure were analyzed even better. Also, the forecasts improved substantially. We expect that the impact of these winds in NWP models can be enhanced not only by further research on and development of assimilation methods, but also by an improved representation of the upper-a.
Multiple-model estimation with variable structure. III. Model-group switching algorithm

A general multiple-model (MM) estimator with a variable structure (VSMM), railed model-group switching (MGS) algorithm, is presented. It assumes that the total set of models can be covered by a number of model groups, each representing a cluster of closely related system behavior patterns or structures, and a particular group is running at any given time determined by a hard decision. This algorithm is the first VSMM estimator that is generally applicable to a large class of problems with hybrid (continuous and discrete) uncertainties. It is also easily implementable. It is illustrated, via a simple fault detection and identification example, that the MGS algorithm provides a substantial reduction in computation while having identical performance with the fixed-structure Interacting Multiple-Model (FSIMM) estimator.
Two-dimensional secondary instabilities in a strongly stratified shear layer

In a stably stratified shear layer, thin vorticity layers (‘baroclinic layers’) are produced by buoyancy effects and strain in between the Kelvin–Helmholtz vortices. A two-dimensional numerical study is conducted, in order to investigate the stability of these layers. Besides the secondary Kelvin–Helmholtz instability, expected but never observed previously in two-dimensional numerical simulations, a new instability is also found. The influence of the Reynolds number (Re) upon the dynamics of the baroclinic layers is first studied. The layers reach an equilibrium state, whose features have been described theoretically by Corcos & Sherman (1976). An excellent agreement between those predictions and the results of the numerical simulations is obtained. The baroclinic layers are found to remain stable almost up to the time the equilibrium state is reached, though the local Richardson number can reach values as low as 0.05 at the stagnation point. On the basis of the work of Dritschel et al. (1991), we show that the stability of the layer at this location is controlled by the outer strain field induced by the large-scale Kelvin–Helmholtz vortices. Numerical values of the strain rate as small as 3% of the maximum vorticity of the layer are shown to stabilize the stagnation point region. When non-pairing flows are considered, we find that only for Re ≤ 2000 does a secondary instability eventually amplify in the layer. (Re is based upon half the initial vorticity thickness and half the velocity difference at the horizontally oriented boundaries.) This secondary instability is not of the Kelvin–Helmholtz type. It develops in the neighbourhood of convectively unstable regions of the primary Kelvin–Helmholtz vortex, apparently once a strong jet has formed there, and moves along the baroclinic layer while amplifying. It next perturbs the layer around the stagnation point and a secondary instability, now of the Kelvin–Helmholtz type, is found to develop there. We next examine the influence of a pairing upon the flow behaviour. We show that this event promotes the occurrence of a secondary Kelvin–Helmholtz instability, which occurs for Re ≥ 400. Moreover, at high Reynolds number (≥ 2000), secondary Kelvin–Helmholtz instabilities develop successively in the baroclinic layer, at smaller and smaller scales, thereby transferring energy towards dissipative scales through a mechanism eventually leading to turbulence. Because the vorticity of such a two-dimensional stratified flow is no longer conserved following a fluid particle, an analogy with three-dimensional turbulence can be drawn.
Excited hydrogen and the formation of molecular hydrogen via associative ionization – I. Physical processes and outflows from young stellar objects

Rates for the associative ionization reaction H(n=2)+H→H+2+e− are calculated. This reaction is found to be a greater contributor to the H2 formation rate than the direct radiative association reaction H(n=2)+H→H2+hν in most regions of astrophysical interest. Chemical models of circumstellar regions are reassessed in the light of this information. We also examine the chemical behaviour of several other excited chemical species. A critical examination reveals that excitation effects are, in general, very important in many astrophysical situations and must be incorporated into the chemistry. H2 has been detected in a variety of circumstellar regions and has a pivotal role in the overall chemistry. The method and efficiency of its formation are therefore of great importance. We test the significance of the associative ionization reaction in several models. These models include a schematic description of the radiative transfer in H I Lyα. The endothermicity (≃ 1.1 eV) of the reaction and the high departures from LTE that are required for the H I (n = 2) level to be sufficiently populated restrict its significance to regions of high excitation, such as are found in circumstellar regions. In this paper (I), we investigate the importance of the reaction in winds associated with young stellar objects. In Paper II, the investigation will be extended to include novae, supernovae, planetary nebulae and shocked regions. The results indicate that reactions involving excited atomic states may be very important in a number of circumstellar chemistries. Only exceptionally will reactions involving the higher excited states (n > 2) be as significant as those involving H(n = 2).
Statistical roles of storms and substorms in changing the entire outer zone relativistic electron population

[1] Since storms/substorms can lead to flux enhancements of relativistic electrons (E > 500 keV) in one region of the outer zone (L ∼ 2–7) and simultaneously to flux decreases in another region, the final effects of storms/substorms on changing the entire outer zone relativistic electron population are indicated by the total flux variation of the entire outer zone relativistic electrons. The total flux of the relativistic electrons is the summation of their omnidirectional integral fluxes over the entire outer zone. By analyzing the total flux variations of relativistic electrons in the entire outer zone during about 18 storms from August 1990 to March 1991, this paper investigates the statistical relationships between the total flux variations of the entire outer zone relativistic electrons and the intensities of storms/substorms. The statistical results indicate that the primary impact of a storm development is the net loss of relativistic electrons from the entire outer zone via the main phase losses of relativistic electrons, whereas the continuous intense substorm activity (average AE > 200 nT) can lead to the net increases of the relativistic electrons in the entire outer zone. Furthermore, the more intense the substorm activity, the larger the increases of the relativistic electrons, indicating that the continuous intense substorm activity can effectively supply relativistic electrons for the entire outer zone. Since the net increases of the relativistic electrons usually occur during the continuous intense substorm activity, the effective acceleration of the relativistic electron is correlated with the continuous intense substorm activity, e.g., the stochastic acceleration of electron by whistler mode chorus waves.
INFLUENCE OF NAKED NECK GENE (Na) AND DIETARY PROTEIN LEVEL ON GROWTH PERFORMANCE AND CARCASS PARTS AND COMPOSITION OF MALE SHARKASI CHICKENS

: A total number of 770 males from three genotypes, namely heterozygous naked neck (Na/na), homozygous naked neck (Na/Na) and normally feathered (na/na) were compared for growth and meat production performance at two levels of dietary protein (15 and 17% till 8 wks and 13 and 15% till 16 wks). The main results could be summarized as follows:
The Measurement Of Conversion Noise In X-Ray Intensifying Screens

A significant source of noise in screen-film radiography results from the variation in light output of the screen for absorption of x-rays of equal energy. Two methods are described in the literature for measuring the statistics of the number of light quanta emitted for each absorbed x-ray. The coincidence method registers x-ray events by detecting temporally correlated light quanta. It is limited in its ability to see events having a small number of quanta and can be biased by non-Poisson photomultiplier dark events. The pulse height method uses pulse shaping to produce pulses whose height is proportional to the number of quanta. In this case small pulses may be lost in order to discriminate against photomultiplier dark counts. We present a new method, based on the synchronous detection of a chopped x-ray source, which has the potential to avoid these shortcomings. Analytical methods necessary to remove the effects of unwanted x-ray energy components (such as backscatter radiation from our x-ray fluorescent targets) are discussed which provide stable estimates of the first and second moments of the light emission statistics. The method is then used to obtain a new set of measurements of the light emission statistics (including the mean light output and Swank I factor) for samples of Kodak Lanex x-ray intensifying screens for mean incident x-ray energies of 14.4, 17.8, 27.9, 35.2, 42.1, 49.8, and 59.6 keV.
High-power laser beam shaping using apodized apertures

This paper gives the results of the investigations of four types of apodized (soft) apertures for beam shaping of UV, visible and IR high-power lasers with near-Gaussian and flat-top transmittance. The apodized apertures (AA) are ≈3–45 mm in diameter, but the principles of fabrication of such apertures lends the possibility of apodizing beams with diameter 200 mm. The examples of studies of the AA in high-power lasers are presented. The possibility of avoiding the Fresnel diffraction ripples is proved experimentally.
Properties of magnetic tunnel junctions with a MgO/CoFeB/Ta/CoFeB/MgO recording structure down to junction diameter of 11 nm

We investigate properties of perpendicular anisotropy magnetic tunnel junctions (MTJs) with a recording structure of MgO/CoFeB/Ta/CoFeB/MgO down to junction diameter (D) of 11 nm from 56 nm. Thermal stability factor (Δ) of MTJ with the structure starts to decrease at D = 30 nm. D dependence of Δ agrees well with that expected from magnetic properties of blanket film taking into account the change in demagnetizing factors of MTJs. Intrinsic critical current (IC0) reduces with decrease of D in the entire investigated D range. A ratio of Δ to IC0 shows continuous increase with decrease of D down to 11 nm.
GENERAL EQUATIONS OF ANISOTROPIC PLATES AND SHELLS INCLUDING TRANSVERSE SHEAR DEFORMATIONS, ROTARY INERTIA AND INITIAL CURVATURE EFFECTS

The present work deals with a generalization of geometrically linear shear deformation theory for multilayered anisotropic shells of general shape. No assumptions are made other than to neglect the transverse normal strain. The results, which include the effects of shear deformations and rotary inertia as well as initial curvature (included in the stress resultants and assumed transverse shear stresses) are deduced by application of the virtual work principle, with displacements and transverse shear as independent variables. These equations are applied to different shell geometries, such as revolution, cylindrical, spherical and conical shells as well as rectangular and circular plates.
Measurement of three-dimensional velocity profiles using forward-scattering particle image velocimetry (FSPIV) and neural net pattern recognition

We employ Forward Scattering Particle Image Velocimetry (FSPIV) to measure all three components of the velocity of a buoyant polystyrene particle in oil. Unlike conventional particle image velocimetry (PIV) techniques, FSPIV employs coherent or partially coherent back illumination and collects the forward scattered wavefront; additionally, our field-of-view is microscopic. Using FSPIV, it is possible to easily identify the particle's centroid and to simultaneously obtain the fluid velocity in different planes perpendicular to the viewing direction without changing the collection or imaging optics. We have trained a neural network to identify the scattering pattern as function of displacement along the optical axis (axial defocus) and determine the transverse velocity by tracking the centroid as function of time. We present preliminary results from Mie theory calculations which include the effect of the imaging system. To our knowledge, this is the first work of this kind; preliminary results are encouraging.
Dark count probability and quantum efficiency of avalanche photodiodes for single-photon detection

We propose a physical model that quantitatively describes the behavior of the dark count probability and single-photon quantum efficiency of avalanche diodes under conditions that allow these devices to be used for single-photon detection. The model shows analytically how various physical parameters such as dark current, dc gain, Geiger mode gain, carrier detrap time, pulse repetition rate, etc., can affect the dark count probability and single-photon quantum efficiency of a Geiger mode avalanche photodiode. The theory agrees well with the experimental results.
The collimation of magnetized winds

It is established that any stationary axisymmetric magnetized wind will collimate along the symmetry axis at large distances from the source. This result is proved by consideration of the asymoptotic properties of the transfield equation, keeping the exact conserved quantities along field lines. The only consistent nonsingular solution with a nonvanishing poloidal current approaches a cylindrical structure. For singular solutions or those with a vanishing poloidal current, the asymptotic solutions can be paraboloidal. This result only applies to pure wind boundary conditions on the surface of the source. It is shown how the boundary conditions and the critical point analysis are related in our asymptotic analysis. This result demonstrates that axisymmetric magnetized flows tend generally to collimate, and it is hypothesized that this is the natural reason why there are so many collimated flows and jets. 15 refs.
The effect of arsenic overpressure on the structural properties GaAs grown at low temperature

The structural properties of GaAs grown by molecular‐beam epitaxy at low temperatures have been investigated by scanning electron microscopy, transmission electron microscopy, and high‐resolution x‐ray double‐crystal rocking curves as a function of arsenic overpressure during growth. It was found that surface smoothness and excess arsenic incorporation both depend strongly on growth temperature and on As/Ga flux ratio. For each growth temperature there is a ‘‘window’’ in the flux ratio which results in smooth surfaces. As‐grown layers have an increased lattice constant in the growth direction. This relative lattice expansion increases with flux ratio at a constant growth temperature and eventually saturates. Transmission electron micrographs have revealed the presence of arsenic precipitates in material annealed at 600 °C. Increasing the As4 pressure during growth results in increases in precipitate diameter by almost 50% while their density and shape remain constant. Based on these observations a model h.
Some simple solutions for heat‐induced tropical circulation

A simple analytic model is constructed to elucidate some basic features of the response of the tropical atmosphere to diabatic heating. In particular, there is considerable east-west asymmetry which can be illustrated by solutions for heating concentrated in an area of finite extent. This is of more than academic interest because heating in practice tends to be concentrated in specific areas. For instance, a model with heating symmetric about the equator at Indonesian longitudes produces low-level easterly flow over the Pacific through propagation of Kelvin waves into the region. It also produces low-level westerly inflow over the Indian Ocean (but in a smaller region) because planetary waves propagate there. In the heating region itself the low-level flow is away from the equator as required by the vorticity equation. The return flow toward the equator is farther west because of planetary wave propagation, and so cyclonic flow is obtained around lows which form on the western margins of the heating zone. Another model solution with the heating displaced north of the equator provides a flow similar to the monsoon circulation of July and a simple model solution can also be found for heating concentrated along an inter-tropical convergence line.
High power resonantly pumped holmium-doped fibre sources

Holmium-doped fibres provide a power scalable gain-medium capable of operation at wavelengths beyond 2.05 μm. We discuss and review our approach to the power scaling of pulsed and CW laser sources at 2.1 μm using holmium-doped fibres. This paper outlines experiments which demonstrate the wavelength region accessible using holmium-doped silica fibres, as well as a linearly polarised pulsed master-oscillator power amplifier and high average power CW laser and amplifier systems. These devices demonstrate the applicability of holmium fibre lasers to a range of scientific, medical, industrial and defence applications.