Miracle-dz/UniFAR-FTUs huggingface dataset:
Single-crystal Si formed on amorphous substrate at low temperature by nanopatterning and nickel-induced lateral crystallization

Single-crystal silicon has been achieved by patterning amorphous silicon film on silicon dioxide substrate into nanoscale lines and nickel-induced lateral crystallization. Line width affects the single-crystal silicon formation significantly. Narrow line widths, 30 nm or less, resulted in little lateral crystallization; while for line widths above 250 nm, multiple grains started to form. In-situ transmission electron microscope observation has been used to study the crystallization process. Lithography-constrained single seeding is proposed to explain the single-crystal formation.
TiO2 sol-gel thin films containing Au and Pt nanoparticles with controlled morphology: optical study and gas sensing properties

Au and Pt nanoparticles are prepared with colloidal techniques in order to achieve high morphological quality, capped with a polymer and then embedded inside a TiO2 sol-gel matrix, resulting in a homogeneous dispersion of both metal colloids, confirmed by TEM analyses. Refractive index values measured with ellipsometry increase with the annealing temperature, with quite a linear trend, and at the same time the Au surface plasmon resonance peak undergoes a red shift: the refractive index evaluated from the Au plasmon band is slightly lower than the measured value, indicating that the refractive index just around metal particles is different from the average of the matrix, likely because of the polymeric capping agent. Optical gas sensing tests towards CO and H2 are presented as one of the possible applications of these nanocomposites.
A new solar cycle model including meridional circulation

A kinematic model is presented for the solar cycle which includes not only the transport of magnetic flux by supergranular diffusion and a poleward bulk flow at the sun's surface, but also the effects of turbulent diffusion and an equatorward 'return flow' beneath the surface. As in the earlier models of Babcock and Leighton, the rotational shearing of a subsurface poloidal field generates toroidal flux that erupts at the surface in the form of bipolar magnetic regions. However, such eruptions do not result in any net loss of toroidal flux from the sun (as assumed by Babcock and Leighton); instead, the large-scale toroidal field is destroyed both by 'unwinding' as the local poloidal field reverses its polarity, and by diffusion as the toroidal flux is transported equatorward by the subsurface flow and merged with its opposite hemisphere counterpart. The inclusion of meridional circulation allows stable oscillations of the magnetic field, accompanied by the equatorward progression of flux eruptions, to be achieved even in the absence of a radial gradient in the angular velocity. An illustrative case in which a subsurface flow speed of order 1 m/s and subsurface diffusion rate of order 10 sq km/s yield 22-yr oscillations in qualitative agreement with observations.
Circuit-Field Coupling and Magnetic-Thermal Coupling Analysis of RRF Converter Designed With Magnetic Integration

In this paper, the magnetic integration of resonant reset forward (RRF) converter and magnetic-thermal coupling analysis of integrated magnetic (IM) components are explored. The formulas of magnetic reluctance, winding turns, and magnetic flux density are obtained based on the equivalent magnetic circuit and minimum current pulsation scheme. Meanwhile, circuit-field coupling model of RRF converter and magnetic-thermal coupling model of IM components are built with the finite-element analysis (FEA) method. The simulation results illustrate that the core of the integrated RRF converter works in an unsaturated condition, the temperature rise of IM components is about 20 °C, and the integrated RRF converter has almost the same power efficiency as the conventional discrete RRF converter. Furthermore, hardware prototypes are fabricated and tested to verify the simulation accuracy and design validity. The conclusion of this paper will provide a reference for improving magnetic integration efficiency in the future design of RRF converter.
A City-Based Design That Attempts to Improve National Representativeness of Asians

Abstract This article describes a case study on the potential of using smaller geographical units in an area probability design, and reports the challenges of collecting a nationally representative sample for this hard-to-reach population. The Census Integrated Communications Program Evaluation (CICPE) was designed to evaluate the promotional campaign’s effect on Decennial Census participation for six race/ethnicity groups of interest. A nationally representative Core sample was designed to collect interviews for Hispanics, non-Hispanic African-Americans, and non- Hispanic Whites. However, it was impractical to include the rarer Asian, American Indian and Alaska Native (AIAN), and Native Hawaiian and Other Pacific Islander (NHOPI) populations in the Core design. For the Asian sample, we designed a separate area probability sample. Traditional area probability sampling designs use counties or metropolitan areas as first-stage units, but smaller geographical units can better target hard-to-reach populations. The CICPE Asian sample used cities as the first-stage units.
Finite element study of time‐dependent Maxwell's equations in dispersive media

In this article, we consider the time‐dependent Maxwell's equations in a bounded domain when dispersive media are involved. The Crank‐Nicolson scheme is developed to approximate the electric field equation by Nedelec edge elements and is proved to be optimal convergent in energy norm. The analysis is carried out for Debye medium, but the same results hold true for other dispersive media such as plasma and Lorentz medium. Furthermore, our analysis extends straightforward to cases when a dispersive medium and a simple medium (such as air) are coupled. Mathematics Subject Classification (2000): 65N30, 35L15, 78‐08. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008
Volume Inequalities for L p -Zonotopes

The classical Minkowski sum of convex sets is defined by the sum of the corresponding support functions. The L p -extension of such a definition makes use of the sum of the p th power of the support functions. An L p -zonotope Z p is the p -sum of finitely many segments and is isometric to the unit ball of a subspace of l q , where 1/ p + 1/ q = 1. In this paper, a sharp upper estimate is given of the volume of Z p in terms of the volume of Z 1 , as well as a sharp lower estimate of the volume of the polar of Z p in terms of the same quantity. In particular, for p = 1, the latter result provides a new approach to Reisner's inequality for the Mahler conjecture in the class of zonoids.
Coupling of Two Absorbing Boundary Conditions for 2D Time-Domain Simulations of Free Surface Gravity Waves

The numerical simulation of nonlinear gravity waves propagating at the surface of a perfect fluid is now usually solved by totally nonlinear time-domain numerical models in two dimensions, and this approach is being extended to three dimensions. The original initial boundary value problem is posed in an unbounded region, extending horizontally up to infinity to model the sea. Its numerical solution requires truncating the domain at a finite distance. Unfortunately, no exact nonreflecting boundary condition on the truncating surface exists in this time-domain formulation. The proposed strategy is based on the coupling of two previously known methods in order to benefit from their different, and complementary, bandwidth: the numerical “beach,” very efficient in the high frequency range; and a piston-like Neumann condition, asymptotically ideal for low frequencies. The coupling method gives excellent results in the whole range of frequencies of interest and is as easy to implement in nonlinear as in linear versions. One of its major advantages is that it does not require any spectral knowledge of the incident waves.
The Treatment of Non-LTE Line Blanketing in Spherically Expanding Outflows

Extensive modifications to the non-LTE radiative transfer code of Hillier have been made in order to improve the spectroscopic analysis of stars with stellar winds. The main improvement to the code is the inclusion of blanketing due to thousands of overlapping lines. To implement this effect, we have used the idea of super levels first pioneered by Anderson. In our approach, levels with similar excitation energies and levels are grouped together. Within this group, we assume that the departure coefficients are identical. Only the population (or equivalently, the departure coefficient) of the super level need be solved in order to fully specify the populations of the levels within a super level. Our approach is a natural extension of the single-level LTE assumption, and thus LTE is recovered exactly at depth. In addition to the line blanketing modifications, the code has been improved significantly in other regards. In particular, the new code incorporates the effect of level dissolution, the influence of resonances in the photoionization cross sections, and the effect of Auger ionization. Electron scattering with a thermal redistribution can be considered, although it is normally treated coherently in the comoving frame (which still leads to redistribution in the observer's frame). Several example calculations are described to demonstrate the importance of line blanketing on spectroscopic analysis. We find that the inclusion of blanketing modifies the strengths of some optical CNO lines in Wolf-Rayet (W-R) stars by factors of 2-5. In particular, the strengths of the WC classification lines C III λ5696 and C IV λ5805 are both increased because of iron blanketing. This should help alleviate problems found with nonblanketed models, which were incapable of matching the strengths of these lines. We also find that, in the UV (1100-1800 Å), the influence of Fe is readily seen in both emission and absorption. The emission is sensitive to the iron abundance and should allow, for the first time, Fe abundances to be deduced in W-R stars. The improvements made to our code should greatly facilitate the spectroscopic analysis of stars with stellar winds. We will be able to determine the importance and influence of line blanketing, as well as of several other effects that have been included in the new code. It will also allow us to better determine W-R star parameters, such as luminosity, elemental abundances, wind velocity, and mass-loss rate. With future application to related objects, such as novae and supernovae, our new code should also improve our understanding of these objects with extended outflowing atmospheres.
Modelling of laser-plasma electron acceleration in capillary tubes

Modelling of electron acceleration driven by laser wakefield in centimetre-long capillary tubes was performed and compared with experimental results. Simulations using the WAKE code (Mora and Antonsen 1997 Phys. Plasma 4 217) were compared with the results of the 3D particle-in-cell CALDER-CIRC code (Lifschitz et al 2009 J. Comput. Phys. 228 1803). The results give some insight into the role of guiding to achieve electron energies of the order of 250 MeV with modest input laser intensities (∼0.77 × 1018 W cm−2) and low plasma densities (n = 5 × 1018 cm−3).
Calculation of atomic integrals using commutation relations

In this paper, a numerically stable method of calculating atomic integrals is suggested. The commutation relations among the components of the angular momentum and the Runge-Lenz vector are used to deduce recurrence relations for the Sturmian radial functions. The radial part of the one- and two-electron integrals is evaluated by means of these recurrence relations. The product of two radial functions is written as a linear combination of the radial functions. This enables us to write the integrals over four radial functions as a linear combination of the integrals over two radial functions. The recurrence relations for the functions are used to derive the recursion relations for the coefficients of the linear combination and for the integrals over two functions.
Students' Retention of Mathematical Knowledge and Skills in Differential Equations

This study investigates students' retention of mathematical knowledge and skills in two differential equations classes. Posttests and delayed posttests after 1 year were administered to students in inquiry-oriented and traditional classes. The results show that students in the inquiry-oriented class retained conceptual knowledge, as seen by their performance on modeling problems, and retained equal proficiency in procedural problems, when compared with students in the traditionally taught classes. The results of this study add additional support to the claim that teaching for conceptual understanding can lead to longer retention of mathematical knowledge.
Inversion technique to obtain an emissivity profile from tangential line‐integrated hard x‐ray measurements

A matrix inversion technique has been developed to calculate local x‐ray emissivity profiles from line‐integrated x‐ray measurements from an anisotropic source. A 2D hard x‐ray camera has been used to measure tangential line‐integrated bremsstrahlung emission from suprathermal electrons generated by lower hybrid current drive in the PBX‐M tokamak. Local emissivities, E, on the midplane of the tokamak are useful to localize the lower hybrid‐driven current. The anisotropy is assumed to be uniform over the plasma with a form E(R,θ)=E(R)cosn(θ), where E(R) is the forward emissivity at the major radius R, θ is the angle to the camera from tangency, and the exponent n defines the degree of anisotropy. For isotropic emission, n=0. The measured brightness B(R) on the midplane is then related to the forward emissivity E(R) by a matrix M=L(R,φ)cosn[θ(R,φ)], where φ is the toroidal angle, L is a length matrix containing the path lengths through the plasma. By inverting the matrix M, the forward emissivity is obtaine.
Formation of Protoplanets from Planetesimals in the Solar Nebula

Planetary accretion from planetesimals to protoplanets is investigated using three-dimensional N-body simulations. The effect of gas drag due to solar nebula is included and realistic-sized planetesimals with a standard material density are used, with which the growth time scale of planetesimals is realistic. In agreement with the earlier works (E. Kokubo and S. Ida 1996, Icarus123, 180–191; 1998, Icarus131, 171–178) that investigated gas-free accretion of planetesimals with enlarged sizes, it is found that a bimodal protoplanet–planetesimal system is formed through runaway and oligarchic growth. In the intermediate accretion stage, the growth mode of planetesimals is runaway growth where the mass distribution relaxes into isolated runaway bodies and the continuous power-law mass distribution with dnc/dm∝mα, where nc is the cumulative number of bodies and α≃−2.5. While thinning out some runaway bodies, the growth mode shifts to oligarchic growth where larger protoplanets tend to grow more slowly than smaller ones. The orbital separations of the protoplanets are kept wider than about 5 Hill radii of the protoplanets through orbital repulsion. In the late accretion stage, similar-sized protoplanets grow, while most planetesimals remain small. Protoplanets with mass 1026 g are formed at 1 AU in 500,000 years.
Minimum energy structures of faceted, incoherent interfaces

In this article, we describe a method for quantifying the dislocation distribution in incoherent faceted fcc/bcc interfaces, including details such as the facet length and crystallography and the location, Burgers vector, and line orientation of each interface dislocation. The method is applied to a variety of relaxed equilibrium interface structures obtained from atomistic simulations. The results show that minimum energy forms of faceted interfaces are achieved when the serrated interface planes of the natural lattice are optimally matched such that when joined and relaxed, extended facet faces can form with minimum density of interface dislocations. With a proposed dislocation-based model for the formation energy, we demonstrate that optimal matching corresponds to minimal self-energies of the interfacial dislocations and extended facets (terrace planes). Most importantly, the formation energy of faceted interfaces is found to have no correlation with the net Burgers vector of the interface, which furt.
Nonlinear evolution of the elliptical instability: an example of inertial wave breakdown

A direct numerical simulation is presented of an elliptical instability observed in the laboratory within an elliptically distorted, rapidly rotating, fluid-filled cylinder (Malkus 1989). Generically, the instability manifests itself as the pairwise resonance of two different inertial modes with the underlying elliptical flow. We study in detail the simplest ‘subharmonic’ form of the instability where the waves are a complex conjugate pair and which at weakly supercritical elliptical distortion should ultimately saturate at some finite amplitude (Waleffe 1989; Kerswell 1992). Such states have yet to be experimentally identified since the flow invariably breaks down to small-scale disorder. Evidence is presented here to support the argument that such weakly nonlinear states are never seen because they are either unstable to secondary instabilities at observable amplitudes or neighbouring competitor elliptical instabilities grow to ultimately disrupt them. The former scenario confirms earlier work (Kerswell 1999) which highlights the generic instability of inertial waves even at very small amplitudes. The latter represents a first numerical demonstration of two competing elliptical instabilities co-existing in a bounded system.
KIR: the high-spatial-resolution 1024 x 1024 near-infrared camera of the Canada-France-Hawaii Telescope

KIR is a 1024 by 1024 near-IR camera used with the adaptive optics Bonnette (PUEO) of the Canada-France-Hawaii Telescope. The camera houses a 1024 by 1024 HgCdTe and simple refractive optics providing diffraction-limited images with an image scale of 0.035 inch/pixel. First light was obtained in December 1997. The throughput of the camera, from the top of the atmosphere down to the atmosphere down to the detector including PUEO, is 19 percent, 20 percent and 21 percent at J, H and K, respectively. This project is a collaboration between the Universite de Montreal, the Observatoire Midi Pyrenees and the Canada-France-Hawaii Telescope. The design and performance of the instrument are presented in this paper.
Coupling dynamic models of climate and vegetation

Numerous studies have underscored the importance of terrestrial ecosystems as an integral component of the Earth's climate system. This realization has already led to efforts to link simple equilibrium vegetation models with Atmospheric General Circulation Models through iterative coupling procedures. While these linked models have pointed to several possible climate–vegetation feedback mechanisms, they have been limited by two shortcomings: (i) they only consider the equilibrium response of vegetation to shifting climatic conditions and therefore cannot be used to explore transient interactions between climate and vegetation; and (ii) the representations of vegetation processes and land‐atmosphere exchange processes are still treated by two separate models and, as a result, may contain physical or ecological inconsistencies.
Power saturation in 2-1 Y-junction diode lasers

An experimental and theoretical study of 2-1 Y-junction semiconductor lasers is presented. In a V-channeled substrate inner stripe laser (VSIS)-type antireflection coated 2-1 Y-junction array lasing at a wavelength of 780 nm, stable in-phase operation is observed up to a CW output power of 100 mW. In uncoated devices, saturation effects occur which limit stable in-phase operation to low-power output. The experimental results are discussed in the framework of a model based on the beam propagation method. >
Possible strengths of dynamo magnetic fields of the Galilean satellites and of Titan

Simple models for the interiors of the Galilean satellites and Titan involving metallic cores have been constructed. Then using a similarity law due to Busse possible surface equatorial dynamo magnetic fields of 2200, 800, 200, 60 and 100 nT have been estimated for Io through Titan, respectively.
ITERATIVE SOLUTION OF IMPLICIT APPROXIMATIONS OF MULTIDIMENSIONAL PARTIAL DIFFERENTIAL EQUATIONS

Summary. A new iterative method has been developed for solving the large sets of algebraic equations that arise in the approximate solution of multidimensional partial differential equations by implicit numerical techniques. This method has several advantages over those now in use. First, its rate of convergence does not depend strongly on the nature of the coefficient matrix of the equations to be solved. Second, it is not sensitive to the choice of iteration parameters, and as a result, suitable parameters can be estimated from the coefficient matrix. Finally, it reduces significantly the computational effort needed to solve a set of equations. For a typical set of 961 equations, it was found to reduce the number of calculations by a factor of three, when compared to the most competitive of the older methods. It is expected that this advantage will be even greater for larger sets of equations. 1. Introduction. Approximate solutions of multidimensional differential equations often are obtained by the application of implicit finite difference analogues. A difference equation is written for each grid point in the region of interest, and the resulting set of simultaneous equations must be solved for each time step. Such sets of equations can be solved directly by elimination or by one of several iterative methods, such as relaxation, successive overrelaxation, or ADI (alternating direction iteration). The purpose of this paper is to describe a new iterative procedure that converges much faster than any of these methods. The simplest method of solving these sets of equations is direct solution by elimination. Although this approach is the most efficient method available for small sets of equations, it is not for large sets. The procedure requires 2n2 arithmetic operations to solve n equations of the type being considered. When n becomes relatively large, it is more efficient to use an
Quantum trajectory model for photon detectors and optoelectronic devices

We consider a single-mode optical cavity field with simultaneous dissipative and amplifying couplings to a reservoir via a two-state system. In previous works, the reservoir has either solely absorbed energy (detector setup) or added energy (amplifying setup) to the cavity. In this work, we allow both interactions simultaneously and derive a reduced dynamic model for the optical field. Our model includes four physical parameters: the field-two-state system coupling γ, the excitation and de-excitation couplings of the two-state system to the reservoir λA and λD, respectively, and the mirror losses of the cavity C. We show that, depending on the parameters, our setup can operate as a detector, a light-emitting diode or a laser. We also consider single-photon subtraction and addition schemes based on beam splitters and calculate the output fields and the probabilities of the subtraction and addition events. Furthermore, we discuss which are the parameter regimes in which our model is equivalent to beam splitter-based schemes.