Miracle-dz/UniFAR-FTUs huggingface dataset:
Increased efficiency of silicon light-emitting diodes in a standard 1.2-μm silicon complementary metal oxide semiconductor technology

Scaled versions of a variety of silicon light-emitting diode elements (Si LEDs) have been realized using a standard 1.2-µm, doublepolysilicon, double-metal, n-well CMOS fabrication process. The devices operated with a n+p junction biased in the avalanche breakdown mode and were realized by using standard features of the ORBIT FORESIGHT design rules. The elements emit optical radiation in a broad band in the 450- to 850-nm range. An emitted intensity (radiant exitance) of up to 7.1 µW/cm2 (or about 8 nW per 60-µm-diam chip area) has been obtained with 5 mA of current at an operating voltage of 18.5 V. Excellent uniformity in emission intensity of better than 1% variation was obtained over areas as large as 100x500 µm. A best power conversion efficiency of 8.7x 10-8 and a quantum efficiency of 7.8x 10-7 were measured. All of these values are about one order of magnitude better than previously reported values for Si LED avalanche devices. Coupling between the elements as well as electro-optical coupling between an element and an optical fiber was realized.
Metal–Insulator Transition in Pyrochlore Iridates Ln2Ir2O7 (Ln = Nd, Sm, and Eu)

We report that Ln 2 Ir 2 O 7 for Ln = Nd, Sm, and Eu have metal–insulator transitions (MITs) at 36, 117, and 120 K, respectively. Their electrical resistivities and thermoelectric powers are not discontinuous and exhibit no thermal hysteresis at their transition temperatures T MI , indicating second-order phase transitions. In this letter, we focus on the MIT of Sm 2 Ir 2 O 7 . The specific heat and the magnetic susceptibility show a clear anomaly at T MI . These results indicate that this MIT involves a magnetic ordering produced by 5 d electrons in Ir.
Polynomial approximation of some singular functions

The singularities of the solution of a Poisson equation in a polygonal domain are essentially the distance to a corner, up to a positive but weak power. We prove that the high degree polynomial approximation of such functions is better than the result given by the general theory. This leads to an improvement of the error estimates in some spectral type discretizations
Analysis of the Bernstein basis functions: an approach to combinatorial sums involving binomial coefficients and Catalan numbers

We give some alternative forms of the generating functions for the Bernstein basis functions. Using these forms,we derive a collection of functional equations for the generating functions. By applying these equations, we prove some identities for the Bernstein basis functions. Integrating these identities, we derive a variety of identities and formulas, some old and some new, for combinatorial sums involving binomial coefficients, Pascal's rule, Vandermonde's type of convolution, the Bernoulli polynomials, and the Catalan numbers. Copyright © 2014 John Wiley & Sons, Ltd.
Multifrequency observations of blazars. IV. The variability of the radio to ultraviolet continuum

The results of analysis of the variability properties of the high-frequency radio to UV continua of a sample of nine blazars are presented. The IR and optical variations of the three sources for which detailed comparisons can be made between the light curves obtained at the various wavebands are found to be well correlated. A strong correlation is observed beween the near-IR flux levels and the near-IR spectral slopes of the BL Lac objects, in the sense that the spectra are steeper when the sources are fainter. A similar correlation is observed to hold in optically violent variable (OVV) quasars during large-amplitude flare events; in general, however, the spectra of the OVV quasars exhibit no significant correlation between flux level and spectral slope. An additional nonvariable 1-5 micron component may be present in the near-IR spectra of OVV quasars.
The bow shock and mach disk of HH 111V

We present spatially resolved line profiles in Hα and [S II] λλ6716, 6731 across the working surface region in the Herbig-Haro object HH 111V. Data were acquired with the Rutgers/CTIO imaging Fabry-Perot interferometer on the CTIO 4 m telescope at ∼1″. 3 FWHM spatial and ∼35 km s −1 FWHM kinetic resolution. We separate Mach disk emission spatially and kinematically from the bow shock emission. We have used the Hα flux measured at the apex of the bow shock to estimate the preshock density of ∼200 cm −3 . Our detailed measurements of the electron density as a function of position and velocity across the bow shock, combined with new models of the bow shock emission, show that an ambient magnetic field of ∼30 μG inhibits the compression of the postshock gas
Student Perceptions of the Value of Physics Laboratories

Science instruction literature provides us with goals for laboratory instruction and guidelines for designing and implementing science labs in the post‐secondary setting. How well are we doing in our attempt to provide a meaningful and positive learning experience for our students? This paper describes the results of a study to determine whether students view the lab component of second‐year physics courses at a mid‐sized Canadian University as a valuable learning experience. The results of a survey, administered over six semesters and completed by 168 students, indicate that students do acknowledge the value of labs. The results also identify the factors that influence the students’ perceptions of value in physics labs. This paper discusses the four factors found to have the greatest influence on students’ perceptions of the value of labs: (1) the pressure to complete an experiment within the allotted time, (2) the information provided on the lab instruction sheets, (3) the help provided by lab staff and graduate teaching assistants, and (4) the students’ level of preparedness.
Measurements of the Magnetic Field Geometry and Strength in Bok Globules

In order to study the influence and structure of the magnetic field in the early phases of low-mass star formation, we obtained polarization maps of three Bok globules at a wavelength of 850 μm, using the Submillimeter Common-User Bolometer Array at the James Clerk Maxwell Telescope. We observed the following sources: CB 26, a globule with a nearly dispersed dense core containing a source with a circumstellar disk; CB 54, a deeply embedded young stellar cluster; and DC 253-1.6 (CG 30), a protostellar double core. We find strongly aligned polarization vectors in the case of CB 26 and DC 253-1.6, while the vector orientations in the case of CB 54 are more or less randomly distributed. The degree of polarization, amounting to several percent, was found to decrease toward the center in each source. In the case of CB 54 and DC 253-1.6, the degree of polarization similarly depends on the corresponding intensity. Assuming dichroic emission by aligned nonspherical grains as the polarization mechanism, where the magnetic field plays a role in the alignment process, we derive magnetic field strengths and structures from the observed polarization patterns. In the case of the double core DC 253-1.6, we discuss the correlation between the fragmentation process and the magnetic field direction.
Rainfall measurements at Ku-band satellite link in Penang, Malaysia

The rainfall path attenuation at 12.255 GHz measured at Universiti Sains Malaysia for 5 years (2002-2006) is presented. The data obtained are useful to investigate the impairment because of rainfall attenuation in satellite links operating in tropical and equatorial climates. The path attenuation increases significantly with the rainfall rate measured on the ground, with rain fades exceeding 20 dB being measured at rainfall rates of 130 mm/h. Maximum exceeded time for rain rate and attenuation were observed during the wet months. The cumulative distributions of attenuation derived from the measured data are presented and compared with those obtained with existing prediction methods.
Assessing Evidence Inconsistency in Mixed Treatment Comparisons

Randomized comparisons among several treatments give rise to an incomplete-blocks structure known as mixed treatment comparisons (MTCs). To analyze such data structures, it is crucial to assess whether the disparate evidence sources provide consistent information about the treatment contrasts. In this article we propose a general method for assessing evidence inconsistency in the framework of Bayesian hierarchical models. We begin with the distinction between basic parameters, which have prior distributions, and functional parameters, which are defined in terms of basic parameters. Based on a graphical analysis of MTC structures, evidence inconsistency is defined as a relation between a functional parameter and at least two basic parameters, supported by at least three evidence sources. The inconsistency degrees of freedom (ICDF) is the number of such inconsistencies. We represent evidence consistency as a set of linear relations between effect parameters on the log odds ratio scale, then relax these relations to allow for inconsistency by adding to the model random inconsistency factors (ICFs). The number of ICFs is determined by the ICDF. The overall consistency between evidence sources can be assessed by comparing models with and without ICFs, whereas their posterior distribution reflects the extent of inconsistency in particular evidence cycles. The methods are elucidated using two published datasets, implemented with standard Markov chain Monte Carlo software.
Extreme Evapotranspiration by Irrigated Alfalfa: A Consequence of the 1976 Midwestern Drought

Abstract The rate of evapotranspiration by irrigated alfalfa at Mead, NE (41°09′N; 96°30′W, elevation 354 m) reached record levels in 1976. Evapotranspiration was measured with precision weighing lysimeters in a field 1.9 ha in size. Evapotranspiration ranged during the growing season from 4.75 to 14.22 mm day−1 and exceeded 10 mm day−1 on one-third of the days studied. On each day of study the ratio of latent heat flux density (LE) to the sum of the net radiation and soil heat flux densities (Rn + S) was such that LE/(Rn + S) > 1, indicating the occurrence of significant sensible heat advection. On clear days during mid-summer the net radiation provides energy sufficient for evaporation of no more than 7 mm day−1. Sensible heat advection provided the remaining energy consumed in evapotranspiration. The unusually strong sensible heat advection likely was due to the generally dry condition of surrounding regions during the drought of 1976.
The motion of a low-pressure arc in a strong magnetic field

A low-pressure arc between copper electrodes has been driven by a transverse magnetic field of up to 5T. At low field the arc moves in the retrograde direction, but above about 1T the motion changes to the amperian direction. This result is consistent with the theory of retrograde motion proposed by Robson and von Engel (1954).
A Scientific Study of Filter Selection for a Fan-Beam Convolution Reconstruction Algorithm

In previous work an “inversion formula” has been derived which expresses a function of two variables (such as the distribution of x-ray attenuation coefficients in a cross-section) in terms of its integrals along lines diverging from a point which moves around a circle. This inversion formula provides the same kindof theoretical background to divergent beam data collection that Radon’s theorem provides for parallel beam data collection. This formula is important, since rapid data collection in tomographic devices currently implies divergent beam data collection. For practical implementation the formula needs to be “regularized”. In the present paper a theorem is presented and is used for showing the appropriateness of a wide class of functions for the regularization of the inversion formula for divergent beams. Each of these functions is based on a filter and leads to an efficient convolution type numerical implementation. A number of filters are investigated in detail, and their behavior in reconstructing.
The role of p-type doping and the density of states on the modulation response of quantum dot lasers

The modulation response of quantum dot (QD) lasers is analyzed using a quasi-equilibrium approach. The model suggests that present QD lasers are limited due to hole levels that are closely spaced in energy, as well as inhomogeneous broadening. Significant improvements are predicted through p-type modulation doping. The results are consistent with present QD lasers being limited in their modulation response by their differential gain as opposed to carrier capture.
Pressure sensitive multifunctional solar cells using carbon nanotubes

A unique multifunctional device combining the photovoltaic action and pressure sensitivity is demonstrated which is based on the heterojunction of n-Si and carbon nanotubes (double walled carbon nanotubes or multiwalled carbon nanotubes) and using copper phthalocyanine surface modified indium-tin-oxide electrode and shows pressure dependent photovoltaic action. The device can work as a solar cell, pressure sensor, or photovoltaic pressure sensor. Such multifunctional organic/organic-inorganic hybrid solar cells are expected to find many applications in the near future.
Effect of Beta Shear on Simulated Tropical Cyclones

AbstractThrough cloud-resolving simulations, this study examines the effect of β on the evolution of tropical cyclones (TCs). It is found that the TC simulated on a β plane with variable Coriolis parameter f is weaker in intensity but larger in size and strength than the TC simulated on an f plane with constant f. Such differences result mainly from the effect of the β shear rather than from the variation of f due to the latitudinal change of the TC position, as illustrated in a three-stage conceptual model developed herein. The first stage begins with the establishment of the β shear and the emergence of asymmetries as the TC intensifies. The β shear peaks in value during the second stage that subsequently leads to the formation of an extensive stratiform region outside of the primary eyewall. The evaporative cooling associated with the stratiform precipitation acts to sharpen the low-level equivalent potential temperature gradient into a frontlike zone outside of the eyewall region, which leads to the b.
Quantum Noise. IV. Quantum Theory of Noise Sources

For a quantum system describable in a Markoffian way, via a set of variables $\mathrm{a}={{a}_{1}, {a}_{2}, \ensuremath{\cdots}}$, we show that the Langevin noise sources ${F}_{\ensuremath{\mu}}$ in the operator equations of motion $\frac{d{a}_{\ensuremath{\mu}}}{\mathrm{dt}}={A}_{\ensuremath{\mu}}(\mathrm{a})+{F}_{\ensuremath{\mu}}$ possess second moments $〈{F}_{\ensuremath{\mu}}(t){F}_{\ensuremath{\nu}}(u)〉=2〈{D}_{\ensuremath{\mu}\ensuremath{\nu}}(\mathrm{a}, t)〉\ensuremath{\delta}(t\ensuremath{-}u)$. The diffusion coefficients ${D}_{\ensuremath{\mu}\ensuremath{\nu}}$ can be determined from a knowledge of the mean equations of motion via the (exact) time-dependent Einstein relation $2〈{D}_{\ensuremath{\mu}\ensuremath{\nu}}〉=\ensuremath{-}〈{A}_{\ensuremath{\mu}}{a}_{\ensuremath{\nu}}〉\ensuremath{-}〈{a}_{\ensuremath{\mu}}{A}_{\ensuremath{\nu}}〉+\frac{d〈{a}_{\ensuremath{\mu}}(t){a}_{\ensuremath{\nu}}(t)〉}{\mathrm{dt}}$, where $〈 〉$ represents a reservoir average. The sources ${F}_{\ensuremath{\mu}}$, ${F}_{\ensuremath{\nu}}$ do not commute with one another, and as a result the commutation rules of the ${a}_{\ensuremath{\mu}}$ are shown to be preserved in time. The mean motion and diffusion coefficients are calculated for a harmonic oscillator, and for a set of atomic levels. We prove that two dynamically coupled systems (e.g., field and atoms) have uncorrelated Langevin forces if they are coupled to independent reservoirs. Radiation-field-atom coupling adds no new noise sources. We thus obtain simply the maser model including noise sources used in Quantum Noise V. Direct calculations of the mean motion and fluctuations in a system coupled to a reservoir yield relationships in agreement with the Einstein relation. For reservoirs violating time reversal, anomalous frequency shifts are found possible that violate the Ritz combination principle since $\ensuremath{\Delta}{\ensuremath{\omega}}_{12}+\ensuremath{\Delta}{\ensuremath{\omega}}_{23}+\ensuremath{\Delta}{\ensuremath{\omega}}_{31}$ need not vanish.
Depth recovery and refinement from a single image using defocus cues

We present a technique to recover and refine the depth map from a single image captured by a conventional camera in this paper. Our method builds on the universal imaging principle: only scene at the focus distance will converge to a single sharp point on imaging sensor but other scene will yield different blur effects varying with its distance from the camera lens. We first estimate depth values at edge locations via spectrum contrast and then recover the full depth map using a depth matting optimization method. Due to the fact that some blur textures such as soft shadows or blur patterns will produce ambiguity results during the procedure of depth estimation, we use a total variation-based image smoothing method to smooth the original image, a smoothed image with detailed texture being suppressed can be generated. Taking this smoothed image as reference image, a guided filter is used to refine the final depth map.
Verification of Q-QUICK scheme for convective flux in incompressible flow on unstructured grids

Accuracy of convective flux approximation is important for numerical computation of incompressible flow on unstructured grids. The Quasi-QUICK scheme by Davidson is proposed to improve the accuracy of convective flux approximation. The numerical performances of the Q-QUICK scheme on unstructured grids are explored, including numerical accuracy, convergence stability, CPU time consumption and solution sensitivity to high grid deformation. Several test cases such as 90° and 30° 2D lid-driven cavity flows, diverging channel and 3D lid-driven cavity flow are considered. The results show that the Q-QUICK scheme performs well in terms of numerical accuracy, convergence stability or adaptability to high grid deformation if compared with other schemes. Moreover, the convergence speed of momentum equation and CPU time consumptions are also compared for each type of grid and scheme.
Surface scattering in metallic nanowires

Electronic transport with surface scattering in metallic nanowires is studied theoretically based on an atomistic tight-binding approach. It is shown that the mean free path (MFP) strongly depends on the size of the wire and the scattering potential at the surface. In the weak scattering regime, the MFP grows with the wire diameter in an oscillatory manner. A perturbation theory is developed to explain this finite size effect. For narrow wires with small roughness, we show that the surface can be the dominant source of scattering and increases the resistivity well above the bulk value, which will adversely impact the future application of nanowire.
Semiparametric Inference in Seasonal and Cyclical Long Memory Processes

Several semiparametric estimates of the memory parameter in standard long memory time series are now available. They consider only local behaviour of the spectrum near zero frequency, about which the spectrum is symmetric. However long‐range dependence can appear as a spectral pole at any Nyqvist frequency (reflecting seasonal or cyclical long‐memory), where the spectrum need display no such symmetry. We introduce Seasonal/Cyclical Asymmetric Long Memory (SCALM) processes that allow differing rates of increase on either side of such a pole. To estimate the two consequent memory parameters we extend two semiparametric methods that were proposed for the standard case of a spectrum diverging at the origin, namely the log‐periodogram and Gaussian or Whittle methods. We also provide three tests of symmetry. Monte Carlo analysis of finite sample behaviour and an empirical application to UK inflation data are included. Our models and methods allow also for the possibility of negative dependence, described by a possibly asymmetric spectral zero.
Estimating the adsorption energy of element 113 on a gold surface

We report first-principle based studies of element 113 (E113) interactions with gold aimed primarily at estimating the adsorption energy in thermochromatographic experiments. The electronic structure of E113-Aun systems was treated within the accurate shape-consistent small core relativistic pseudopotential framework at the level of non-collinear relativistic density functional theory (RDFT) with specially optimised Gaussian basis sets. We used gold clusters with up to 58 atoms to simulate the adsorption site on the stable Au(111) surface. Stabilization of the E113-Aun binding energy and the net Bader charge of E113 and the neighboring Au atoms with respect to n indicated the cluster size used was appropriate. The resulting adsorption energy estimates lie within the 1.0–1.2 eV range, substantially lower than previously reported values.
The outer solar corona as observed from Skylab - Preliminary results

The white-light coronagraph experiment has made frequent, periodic observations of the solar corona from 1.5 to 6.0 solar radii during the Skylab mission, and these observations will permit the determination of the three-dimensional extent of coronal forms. There are several time scales on which visual changes in coronal structures occur, ranging from approximately one-half rotation to less than hours. A number of events corresponding to the shortest time scale - coronal transients - cause major restructuring of the corona.
The onset of chaos in a class of Navier–Stokes solutions

The flow between parallel walls driven by the time-periodic oscillation of one of the walls is investigated. The flow is characterized by a non-dimensional amplitude Δ and a Reynolds number R. At small values of the Reynolds number the flow is synchronous with the wall motion and is stable. If the amplitude of oscillation is held fixed and the Reynolds number is increased there is a symmetry-breaking bifurcation at a finite value of R. When R is further increased, additional bifurcations take place, but the structure which develops, essentially chaotic flow resulting from a Feigenbaum cascade or a quasi-periodic flow, depends on the amplitude of oscillation. The flow in the different regimes is investigated by a combination of asymptotic and numerical methods. In the small-amplitude high-Reynolds-number limit we show that the flow structure develops on two time scales with chaos occurring on the longer time scale. The chaos in that case is shown to be associated with the unsteady breakdown of a steady streaming flow. The chaotic flows which we describe are of particular interest because they correspond to Navier–Stokes solutions of stagnation-point form. These flows are relevant to a wide variety of flows of practical importance.
Shock-driven implosion of interstellar gas clouds and star formation.

Two-dimensional hydrodynamical calculations are presented to demonstrate a mechanism of star formation which, within the context of the spiral density wave theory, can explain the narrowness of the spiral arms of galaxies delineated by the classic spiral tracers: the bright, young stars and their associated H II regions. The implosion of a standard interstellar cloud has been followed numerically after it encounters a shock in the intercloud medium. Parameters have been chosen to represent a cloud flowing into a spiral arm which is delineated by a shock in the interstellar gas. Although this work is motivated by spiral wave theory, the results should also be indicative of the evolution of a cloud struck, for example, by a supernova shock.