Miracle-dz/UniFAR-FTUs huggingface dataset:
SNR and density limit estimates: a comparison of longitudinal and perpendicular recording

Simplified Neel-Arrhenius analysis is utilized to determine limiting densities versus SNR for longitudinal and keepered-perpendicular media. Dominant transition noise is assumed and the effects of grain size distribution and storage above room temperature are included. Perpendicular recording potentially exhibits a higher density than longitudinal; for example, at SNR=20 dB, the limiting densities are approximately 500 and 100 Gbit/in/sup 2/, respectively.
Morphology and Dynamics of Relativistic Jets

We present a comprehensive analysis of the morphology and dynamics of relativistic pressure-matched axisymmetric jets. The numerical simulations have been carried out with a high-resolution shock-capturing hydrocode based on an approximate relativistic Riemann solver derived from the spectral decomposition of the Jacobian matrices of relativistic hydrodynamics. We discuss the dependence of the jet morphology on several parameters, paying special attention to the relativistic effects caused by high Lorentz factors and large internal energies of the beam flow. The parameter space of our analysis is spanned by the ratio of the beam and ambient medium rest mass density (η), the beam Mach number (Mb), the beam Lorentz factor (Wb), and the adiabatic index (γ) of the equation of state (assuming an ideal gas). Both the ultrarelativistic regime (Wb ≥ 20) and the hypersonic regime (relativistic Mach number greater than 100) have been studied. Our results show that the enhancement of the effective inertial mass of the beam due to relativistic effects (through the specific enthalpy and the Lorentz factor) makes relativistic jets significantly more stable than Newtonian jets. We find that relativistic jets propagate very efficiently through the ambient medium, at speeds that agree very well with those obtained from an estimate based on a one-dimensional momentum balance. The propagation efficiency of a relativistic jet is an increasing function of the beam flow velocity. Relativistic jets seem to give rise to two different morphologies, according to the relevance of relativistic effects. Hot beams (i.e., with internal energies comparable to the beam rest-mass energy) show little internal structure (as they are almost in pressure equilibrium with their surroundings) and relatively smooth cocoons forming lobes near the head of the jet. Highly supersonic models, in which the kinematic relativistic effects due to high beam flow Lorentz factors dominate, display extended cocoons that are overpressured with respect to the environment. The cocoon thickness decreases, and its mean pressure increases with increasing beam Lorentz factor.
A new small-angle X-ray scattering facility utilizing a rotating anode, pin-hole collimation and a position-sensitive proportional counter

A new small-angle X-ray scattering facility which utilizes a 6 kW rotating anode, pin-hole collimation, and a position-sensitive proportional counter has been developed. As presently constructed, the minimum scattering vector κ (= 4π sin θ/2) which can be reached with Cu Kα radiation is 5 × 10−3 A−1. Under these conditions the flux incident on the specimen has been found to be 6 × 105 photons s−1. The system has several advantages compared with traditional long-slit geometries; namely, (i) it can quantitatively measure anisotropic scattering distributions, (ii) it avoids large mathematical corrections of the data for slit-smearing effects, and (iii) it minimizes double Bragg scattering in crystalline materials and multiple diffuse scattering in amorphous or liquid materials. To illustrate the performance of this instrument, the scattering curves obtained from four widely different samples are shown. These are: polyethylene, a neutron-irradiated aluminium single-crystal containing voids, a dilute suspension of Ludox spheres, and duck tendon collagen. Quantitative comparisons of the performance with a Kratky camera and with the neutron small-angle scattering facility in Julich are given.
Defect study on the indium-gallium alloy system of copper chalcopyrites performed on solar cell heterostructures

We report on defect spectroscopy on Cu(In,Ga)Se2 based solar cells with varying gallium content. Our investigations using deep level transient and admittance spectroscopy do not reveal a pronounced qualitative difference in the defect spectra for the case of absorbers containing indium and gallium. Therefore, we conclude that there exists no detrimental defect in the bulk material that generally prohibits one to achieve an increase in efficiency even for solar cells based on absorbers with a gallium to gallium plus indium ratio (GGI) larger than 0.3. The boundary compositions with CuInSe2 and CuGaSe2 absorbers (i.e., GGI=0 and GGI=1, respectively) show additional trap signals. Additionally, a peak width analysis was performed for two defect signals that occur for all absorber compositions. The relative peak width was found to be independent of GGI whereas the activation energies show some correlation with the gallium content of the absorber layer.
Measurement of the axial point spread function in scattering media using single-mode fiber-based optical coherence tomography

The authors studied the axial point spread function of optical coherence tomography for Gaussian intensity profiles emitted from and coupled back into single-mode fibers for signals from a scattering medium. The determined Rayleigh length of the axial point spread function was roughly twice the one measured from the reflection of a mirror. Using the measured point spread function in combination with the single backscatter model allowed determination of the attenuation coefficient of the suspension.
Electronic d-band properties of gold nanoclusters grown on amorphous carbon

The electronic d-band properties are important factors for the emerging catalytic activity of Au nanoclusters of sub-5-nm size. We analyzed the d-band properties of Au nanoclusters grown on amorphous carbon supports by photoelectron spectroscopy using synchrotron-radiation light coupled with high-resolution ion scattering spectrometry which enables us to estimate the size and shape of Au nanoclusters. The d-band width (W{sub d}), d-band center position (E{sub d}), and apparent 5d{sub 3/2}-d{sub 5/2} spin-orbit splitting (E{sub SO}) were determined as a function of a number of Au atoms per cluster (n{sub A}) and an average coordination number (n{sub C}) in a wide range (11<n{sub A}<1600). The W{sub d} and E{sub SO} values decrease steeply with decreasing n{sub A} below {approx}150 owing to band narrowing which is caused by hybridization of fewer wave functions of the valence electrons. However, E{sub d} shifts to the higher binding energy side with decreasing cluster size. The rapid movement of E{sub d} is attributed to the dynamic final-state effect, which results in higher binding energy shifts of core and valence states due to a positive hole created after photoelectron emission. We have estimated the contribution from the final-state effect and derived the approximated initial-state spectra. Modified data, however,more » still show a slight movement of the d-band center away from the Fermi level (E{sub F}) although the E{sub d} values for Au nanoclusters are closer to E{sub F} compared to the bulk value. This behavior is ascribed to the contraction of average Au-Au bond length with decreasing cluster size. « less
An Optimized Algorithm for Constructing LDPC Code with Good Performance

본 논문에서, 성능 좋은 LDPC(Low density parity check) 코드을 위한 태너(Tanner) 그래프를 생성하는 알고리듬을 제안한다. 이 알고리듬은 뎁스 컨스트렌트(depth constraints)를 유지하면서 태너 그래프의 새로운 가지를 생성한다. 이 알고리듬은 그래프의 스토핑 셑(stopping set)을 효과적으로 줄이고, 기존의 다른 알고리듬보다도 낮은 계산복잡도를 갖는다. 모의시험을 통해서 이 알고리듬의 개선된 성능을 확인 할 수 있었다.
All-solid-state quasi-CW yellow laser with intracavity self-Raman conversion and sum frequency generation

Quasi continuous-wave (qCW) yellow emission (pulse duration 5 ms, repetition rate 20 Hz) at 559 nm is demonstrated through intracavity sum frequency generation (SFG) of Stokes and fundamental fields in Nd:YVO4 diode pumped self-Raman laser for the first time. Average in pulse output power at 559 nm was 0.47 W for 22 W of pump power, which corresponds to 2.1% of diode-to-yellow efficiency. The pulsed mode of operation was due to diode pump modulation and was used to reduce thermal stress of the crystal.
ON OHTSUKI'S INVARIANTS OF HOMOLOGY 3-SPHERES.

By analysing Ohtsuki's original work in which he produced a formal power series invariant of rational homology 3-spheres, we obtain a simplified explicit formula for them, which may also be compared with Rozansky's integral expression. We further show their relation to the exact SO(3) Witten-Reshetikhin-Turaev invariants at roots of unity in a stronger form than that given in Ohtsuki's original work.
Statistical aspects of rainfall fields in Southern Italy during a rain enhancement experiment

In this paper, attention is focused on data quality control and exploratory analysis of a large data set built for the evaluation of a rain enhancement project. The properties and characteristics of the rainfall process are studied from a statistical perspective. Data come from a high‐density pluviometric network and this provided a large data set allowing detailed examination of the spatial and temporal structure of rainfall on several scales. Copyright © 2006 John Wiley & Sons, Ltd.
Eulerian‐Eulerian Simulation of Sedimentation of Uniformly‐sized, non‐Brownian Spheres in Viscous Fluids

A Eulerian‐Eulerian 3‐dimensional CFD‐model has been built in order to study the sedimentation process of uniformly‐sized, non‐Brownian spheres in a viscous fluid. It is shown that proper agreement with experimental data for high particle loadings strongly depends on using a correct drag force relation. Convection currents in the carrier phase were observed during simulation. They were found to present a hydraulic resistance to the solids settling. The particle interactions were implemented through a solids stress tensor dependent on the viscosity of the carrier phase and the solids local volume fraction. The completed model was validated by comparison with experimental data.
Leader-following consensus with directed switching topologies

This paper studies the leader-following consensus problem of multi-agent systems with directed switching topologies. Some algebraic properties for a kind of digraph are derived firstly. With the assumption that all the agents are jointly linked to the considered leader across the time interval with some given length, a sufficient condition is given to make all the agents follow the considered leader by means of matrix theory and algebraic graph theory. A simulation example is given to illustrate the theoretical results.
A phenomenological magnetomechanical hysteresis model

To obtain accurate design tools for applications involving giant magnetostrictive materials, magnetomechanical hysteresis effects should be taken into account. The problem consists of determining the magnetization and mechanical strain from the combined past history of magnetic field and mechanical stress. In this work, coupled magnetomechanical hysteresis has been modeled by using simple path‐dependent differentials to accumulate the past history in functions related to the magnetization and strain through material‐dependent parameters. By using anhysteretic curves and a few additional parameters to characterize a material, major, and minor loops with respect to both field and stress have been calculated for Terfenol‐D and have shown good agreement with experiments.
MILLIMETER OBSERVATIONS OF CS, HCO+, AND CO TOWARD FIVE PLANETARY NEBULAE: FOLLOWING MOLECULAR ABUNDANCES WITH NEBULAR AGE

Millimeter and sub-millimeter observations of CO, CS, and HCO+ have been conducted toward five planetary nebulae (PNe: K4-47, NGC 6537 (Red Spider), M2-48, NGC 6720 (Ring), and NGC 6853 (Dumbbell)), spanning an age range of 900–10,000 yr, using the Sub-Millimeter Telescope and the 12 m antenna of the Arizona Radio Observatory. The J = 5 → 4, J = 3 → 2, and J = 2 → 1 transitions of CS at 245, 147, and 98 GHz, as well as the J = 3 → 2 and J = 1 → 0 lines of HCO+ at 268 and 89 GHz, were detected toward each source. At least three rotational transitions of CO have also been observed, including the J = 6 → 5 and J = 4 → 3 lines at 691 and 461 GHz. CS had not been definitively identified previously in PNe, and new detections of HCO+ were made in four of the five nebulae. From a radiative transfer analysis of the CO and CS data, kinetic temperatures of TK ∼ 10–80 K and gas densities of n(H2) ∼ 0.1–1 × 106 cm−3 were determined for the molecular material in these sources. Column densities for CO, CS, and HCO+ were Ntot ∼ 0.2–5 × 1016 cm−2, Ntot ∼ 0.4–9 × 1012 cm−2, and Ntot ∼ 0.3–5 × 1012 cm−2, respectively, with fractional abundances, relative to H2, of f ∼ 0.4–2 × 10−4, f ∼ 1–4 × 10−8, and f ∼ 1 × 10−8, with the exception of M2-48, which had f(HCO+) ∼ 10−7. Overall, the molecular abundances do not significantly vary over a duration of 10,000 yr, in contrast to predictions of chemical models. The abundances reflect the remnant asymptotic giant branch shell material, coupled with photochemistry in the early PN phase. These observations also suggest that PNe eject substantial amounts of molecular material into the diffuse interstellar medium.
The effective mass of electron enhancement in Γ-valley in bulk GaAs under very high electric field investigated by time-domain terahertz spectroscopy

By using the free-space terahertz (THz) electro-optic (EO) sampling technique, the THz waveforms emitted from intrinsic bulk GaAs photoexcited by femtosecond laser pulses under strong bias electric fields up to 300 kV/cm were recorded. The initial acceleration signal in THz emission waveforms, which are corresponding to the acceleration of electrons in the bottom of Γ-valley, has been found to start decreasing with applied electric field above 50 kV/cm, in contrast to the simple picture of electron acceleration in the Γ-valley. This result suggests that the effective acceleration mass of electrons in the Γ-valley significantly increases with increasing F, most likely due to strong band mixing under very high fields.
Multifrequency observations of the BL lacertae objects OQ 530 and ON 325

We present spectral measurements of the two BL Lac objects OQ 530 and ON 325, from radio to ultraviolet frequencies. We infer from published data that the multifrequncy measurements for each source have been made over a timme interval which is short compared with the time scale for variability of the spectral shape. Both sources exhibit spectral curvature between infrared and ultraviolet frequencies. The sources differ from one another in optical variability behavior. The intensity and the spectral shape of OQ 530 vary, but in an uncorrelated manner. The spectral shape of ON 325, however, appears to remains constant during intensity variability. We have applied a nonthermal jet emission model to our data, incorporating both the spectral and time variability information. Relativistic beaming is required to successfully fit the data for OQ 530. The angular size of the jet is predicted to be less than 0.1 milli-arcsec at high radio frequenies. Emission at frequncies less than approx.10 GHz is not described by the model, and must be produced externally to the jet. The model predicts that the source radiates at X-ray frequencies, with Compton radiation being dominant over synchrotron emission. The data for ON 325 do not require a highlymore » relativistic jet, and the X-ray emission detected from the source may be dominated by synchrotron radiation. « less
Modular representations of finite groups of Lie type

283. Nonlinear elasticity, R. Ogden & Y. Fu (eds) 284. Foundations of computational mathematics, R. DeVore, A. Iserles & E. Suli (eds) 285. Rational points on curves over finite fields, H. Niederreiter & C. Xing 286. Clifford algebras and spinors 2nd edn, P. Lounesto 287. Topics on Riemann surfaces and Fuchsian groups, E. Bujalance, A.F. Costa & E. Martinez (eds) 288. Surveys in combinatorics, 2001, J . W.P. Hirschfeld (ed) 289. Aspects of Sobolev-type inequalities, L. Saloffe-Coste 290. Quantum groups and Lie theory, A. Pressley 291. Tits buildings and the model theory of groups, K. Tent 292. A quantum groups primer, S. Majid 293. Second order partial differential equations in Hilbert spaces, G. Da Prato & J. Zabczyk 294. Introduction to operator space theory, G. Pis ier 295. Geometry and integrability, L. Mason & Y. Nutku (eds) 296. Lectures on invariant theory, I . Dolgachev 297. The homotopy theory of simply-connected 4-manifolds, H.J . Baues 298. Higher operads, higher categories, T. Leinster 299. Kleinian groups and hyperbolic 3-manifolds, Y. Komori , V. Markovic & C. Series (eds) 300. Introduction to Möbius differential geometry, U. Hertrich-Jeromin 301. Stable modules and the D(2)-problem, F.E. A. Johnson 302. Discrete and continuous nonlinear Schrödinger systems, M. Ablowitz, B. Prinari & A.D. Trubatch 303. Number theory and algebraic geometry, M. Reid & A. Skorobogatov 304. Groups St Andrews 2001 in Oxford vol. 1, C.M. Campbell, E.F. Robertson & G.C. Smith (eds) 305. Groups St Andrews 2001 in Oxford vol. 2, C.M. Campbell, E.F. Robertson & G.C. Smith (eds) 306. Geometric mechanics and symmetry, J . Montaldi & T. Ratiu (eds) 307. Surveys in combinatorics, 2003, C.D. Wensley (ed) 308. Topology, geometry and quantum field theory, U.L. Tillman (ed) 309. Corings and comodules, T. Brzezinski & R. Wisbauer 310. Topics in dynamics and ergodic theory, S. Bezuglyi & S. Kolyada (eds) 311. Groups: topological, combinatorial and arithmetic aspects, T.W. Müller (ed) 312. Foundations of computational mathematics, Felipe Cucker et al. 313. Transcendental aspects of algebraic cycles, S. Muller-Stach & C. Peters (eds.) 314. Spectral generalizations of line graphs, D. Cvetkovic , P. Rowlinson, S . Simic 315. Structured ring spectra, A. Baker & B. Richter (eds.) 317. Advances in elliptic curve cryptography, I . F. Blake, G. Serouss i , N. Smart 318. Perturbation of the boundary in boundary-value problems, Dan Henry 322. Recent perspectives in random matrix theory and number theory, F. Mezzadri , N.C. Snaith (eds.) 323. Poisson geometry, deformation quantisation and group representations, S. Gutt, J . Rawnsley, D. Sternheimer (eds.)
On simple and supersimple transversal designs

In this paper, the existence of a transversal design TDλ (4, g) is proved for all indices λ satisfying 2 ≤ λ ≤ g such that any two of its blocks intersect in at most two elements. Similar results are obtained for transversal designs without repeated blocks. © 2000 John Wiley & Sons, Inc. J Combin Designs 8: 311–320, 2000
A lens feed for a ring array

A method of feeding a 128-element circular array by means of an R-2R parallel plate lens is presented. The method uses the lens fed by three or four probes at the periphery to excite 32 or 33 elements with the proper amplitude and phase to produce low sidelobe patterns over a broad frequency band. Experimental results are given.
Patchiness in plankton populations

We consider and contrast two mechanisms for the production of spatial pattern in an excitable medium model for plankton populations. The first is Turing or diffusion-driven instability. We find that, since in a turbulent environment the effective diffusivities of phytoplankton and zooplankton are similar, this mechanism is unlikely to produce observable spatial pattern in the ocean. The second mechanism is spatially varying forcing of the system. In order to display the sensitivity to small spatial variation in forcing, we consider the dynamics of an ordinary differential equation system with spatial perturbations to parameters and initial conditions. In the absence of diffusion the excitable nature of the system means that small perturbations can produce very sharp spatial structures, when diffusion is introduced, we find that this patchiness can persist on realistic scales.
Formation of magnetic flux tubes in cylindrical wedge geometry

Three-dimensional (3D) MHD numerical simulations have not been able to demonstrate convincingly the spontaneous formation of large vertical flux tubes. Two-dimensional (2D) magnetoconvection in axisymmetric cylinders forms a central magnetic flux tube surrounded by annular convection rings. To study the robustness of this type of solution in three dimensions, the nonlinear resistive MHD equations are solved numerically in a 3D cylindrical wedge from an initially uniform vertical magnetic field. It is shown that the 2D result is retrieved for small domain radii. However, for larger radii the central axis loses its importance and in this case many convection cells form in the numerical domain. Magnetic flux is captured between cells where flow converges and the reduced amount of flux that congregates at the central axis is eroded by the surrounding convection.
Enhanced evidence in climate models for changes in extratropical atmospheric circulation

Abstract We investigate changes in extratropical atmospheric circulation as derived from the most recent multi-model ensemble of global climate projections. This internationally coordinated systematic data base allows for an accurate assessment of climate change signals against the background of model uncertainty. The multi-model mean time series of the northern-hemisphere (NAM) and southern-hemisphere (SAM) annular modes and of the North Atlantic Oscillation (NAO) are in line with the observed positive trends during the second half of the 20th century and project a further strengthening until the end of the 21st century. For SAM and NAM the simulated changes are unambiguously related to anthropogenic forcing and outperform the level of model uncertainty. This result may imply an enhanced probability for some severe regional impacts of climate change, in particular over extratropical land masses. The climate change signals are noticeably weaker under the B1 mitigation scenario than under the A2 business-as-usual scenario. Ozone forcing has a significant impact on the amplitude of future circulation changes, whereas no systematic effect is found with respect to the models’ top-of-the-atmosphere.
Spatial measurement error in infectious disease models

Individual-level models (ILMs) for infectious disease can be used to model disease spread between individuals while taking into account important covariates. One important covariate in determining the risk of infection transfer can be spatial location. At the same time, measurement error is a concern in many areas of statistical analysis, and infectious disease modelling is no exception. In this paper, we are concerned with the issue of measurement error in the recorded location of individuals when using a simple spatial ILM to model the spread of disease within a population. An ILM that incorporates spatial location random effects is introduced within a hierarchical Bayesian framework. This model is tested upon both simulated data and data from the UK 2001 foot-and-mouth disease epidemic. The ability of the model to successfully identify both the spatial infection kernel and the basic reproduction number (R 0) of the disease is tested.