Miracle-dz/UniFAR-FTUs huggingface dataset:
Piezoresistive properties of carbon nanotubes under radial force investigated by atomic force microscopy

We investigated the piezoresistive properties of single-wall carbon nanotubes (SWCNTs) under the tip-induced force in the radial direction using atomic force microscopy. We found that the conductance of the bundled SWCNTs was modulated by the applied radial force. The polarity and amount of the conductance change were different on every bundle and even dependent on the location where the force was applied. These phenomena were explained by the modulation of the band structures of the SWCNTs, which was caused by the deformation at the critical pressure.
Numerical Simulations of Radiative Cooling beneath the Anvils of Supercell Thunderstorms

Abstract Numerical simulations of supercell thunderstorms that include parameterized radiative transfer and surface fluxes are performed using the Advanced Regional Prediction System (ARPS) to investigate the effects of anvil shadows on the near-storm environment. If the simulated storm is nearly stationary, the maximum low-level air temperature deficits within the shadows are about 2 K, which is roughly half the cooling found in some previous observations. It is shown that the extinction of downwelling shortwave radiation by the anvil cloud creates a differential in the flux of downwelling shortwave radiation between the sun and the shade that is at least an order of magnitude greater than the differential of any other term in either the surface radiation or the surface energy budgets. The loss of strong solar heating of the model surface within the shaded regions leads to a reduction of surface temperatures and stabilization of the model surface layer beneath the anvil. The reduction in vertical mixing .
Integral geometry problem for nontrapping manifolds

We consider the integral geometry problem of restoring a tensor field on a manifold with boundary from its integrals over geodesics running between boundary points. For nontrapping manifolds with a certain upper curvature bound, we prove that a tensor field, integrating to zero over geodesics between boundary points, is potential. For functions and 1-forms, this is shown to be true for arbitrary nontrapping manifolds with no conjugate points. As a consequence, we also establish deformation boundary rigidity for strongly geodesic minimizing manifolds with a certain upper curvature bound.
Spatial principal components analysis on head‐related transfer functions and individualized customization from fewer measurements.

Head‐related transfer function (HRTF) is an individual‐dependent and continuous function of sound source position and frequency. Measurement is a common way to obtain individual HRTFs. It is difficult or even impractical to measure HRTFs with high directional resolution for individual, however. To solve the problem, spatial principal components analysis (SPCA) of HRTFs and resulting customization of individual HRTF from fewer measurements were proposed in present paper. In SPCA, HRTF is decomposed as a weighted combination of common spatial basis functions (CSBFs) which are only direction‐dependent, while the weights are frequency‐ and individual‐independent. The CSBFs were derived from the measured HRTFs of 20 subjects with high directional resolution. Based on the calculated CSBFs, for any new subject, the weight coefficients can be estimated from fewer measured HRTFs data, and subsequently the individual HRTFs with high directional resolution can be customized. SPCA were applied to HRTF magnitudes and .
Model of ferrite-cored probes for eddy current nondestructive evaluation

A model of an axisymmetric probe coil with a cylindrical ferrite core in the presence of a layered conducting half space is developed. The boundary value problem is formulated in terms of the magnetic vector potential, which is expanded in a series of appropriate eigenfunctions. The corresponding eigenvalues are the real roots of a function with the radius and the magnetic permeability of the core as parameters. The unknown coefficients of the series are computed by solving a matrix system, which is formed by applying the usual interface conditions. Expressions are derived for the induced eddy current density and the impedance of the coil. Numerical results for the latter are in good agreement with experimental data.
One-dimensional long-range self-arranged optically bound structures

We used two counter-propagating incoherent (non-interfering) quasi-Bessel beams propagating in a suspension of polystyrene microparticles and created so-called one dimensional optically bound matter. Due to the relatively high degree of homogeneity of the Bessel beams the created self-organized structures were up to 200 micrometers long with well dened distances between objects. Static and dynamic behaviour of each particle in the self- arranged structure was recorded by fast CCD camera and analyzed. The inter-particle distances were compared with the theoretical predictions based on coupled dipole method and very good coincidences were found.
On Filippov’s implicit functions lemma

In 1959 A. F. Filippov published a paper [1] containing a lemma designed for use in the study of optimal control problems. Stated somewhat imprecisely, let k be a continuous function on a compact set Q in a finite dimensional space and with values in a finite dimensional space, and let (u'(t): a? <t <b) be a function with values in Q such that k(u'(.)) is measurable; then there exists a measurable function u from [a, b] to Q such that k(u(t)) ==k(u'(t)). For purposes of stochastic control theory it is desirable to extend this to allow arbitrary measure spaces, instead of intervals of real numbers (Kushner [4]); for purposes of the calculus of variations it is desirable to relax the requirement of compactness on Q. We do both of these (Q may be any separable metric space), and at the same time we permit the values of k to lie in any Hausdorff space; it costs nothing. In ? 2 we give an application to optimal control theory. ADDED IN PROOF. In an abstract in Amer. Math. Monthly 73 (1966), p. 927, M. Q. Jacobs announces a generalization of Filippov's lemma. This generalization is a special case of our Theorem 1.
Comparisons of stochastic matrices, with applications in information theory, statistics, economics, and population sciences

Part 1 Partial orderings among stochastic matrices, Joel E. Cohen et al: introduction notation and definitions generalizations of classical channel comparisons degradation is the same as increasing density Shannon's inclusion implies smaller capacity a simple case - matrices A and B haver only two columns open problems. Part 2 Divergence and contraction coefficients, Gh. Zbaganu: introduction, definitions and notations a generalization of an inequality of Dobrushin the divergence divergence between images of measures via Markov kernels -contraction coefficients a particular case - at most countable spaces behaviour of phi-eta phi(tau) for a fixed Markov kernel tau applications of global divergences to comparison of experiments history of the problem.
Multiple scattering radiance in limb‐viewing geometry

At present, satellite-based limb-viewing measurements in near-UV, visible, and near-IR wavelength range are based on the attenuation of direct solar light (the Stratospheric Aerosol and Gas Experiment instruments). This paper studies a new technique: the measurement of backscattered solar radiance spectrum in limb-viewing geometry. A multiple-scattering backward Monte Carlo algorithm Siro has been constructed for realistic radiative transfer modeling of these measurements. By Monte Carlo simulation the difficult spherical geometry of limb-viewing can be accurately modeled, as can constituent densities and boundary conditions that vary in three dimensions. Previous multiple-scattering models applicable to limb-viewing all assume a spherical shell atmosphere. The backward technique is very efficient for simulating a receiver that has a narrow field of view. In this paper the role of multiple scattering is studied by the Siro model in an atmosphere including scattering by molecules and aerosols and absorption by O 3 . Simulations show that the multiple to total scattering ratio increases from almost zero at 300 nm to ∼ 5-60% at visible and near-IR wavelengths (depending on solar geometry and albedo of Earth's surface). A single-scattering model is not sufficient for the analysis of limb radiance measurements. When the solar zenith angle is small, limb radiance is very sensitive to the surface albedo. A bright spot of diameter 50 km on an otherwise dark surface already causes a noticeable increase of intensity.
The spectrum of the recurrent nova U Scorpii during the 1999 outburst

An optical spectrum covering the range λλ4300–6900 A of the recurrent nova U Sco in outburst was taken on February 26th 1999, only 16 hours after maximum. Broad emission lines of H I, He I, N II, N III were seen on the spectrum, while the emission line of He II λ4686 was not yet seen. The FWHM of the emission component of Hα was 8000 km s−1 and the FWZI was roughly 12000 km s−1. The emission line of Hα had blue (−3250 km s−1), central (+30 km s−1), and red (+2770 km s−1) peaks, among which the red one was the most prominent. A narrow absorption component of Hα blue-shifted by −4850 km s−1 was seen. The other prominent lines had a main emission peak red-shifted by 2000−3000 km s−1 and a weak secondary peak blueshifted by −2000− − 3000 km s−1. Most of He I and N II lines were flanked by a narrow absorption component blue-shifted by about −4300 km s−1 which was a good clue for the detailed identification of these lines. These absorption components and some emission lines of N II faded very rapidly and nearly disappeared one day after our observation. The widths of the emission lines decreased with time. The radial velocities of three emission peaks of Hα were −1560 km s−1, +60 km s−1 and +1800 km s−1on March 14th, 17 days after maximum, when the blue one became stronger than the others. The helium abundance by the number of atom of the ejecta is estimated as N(He)/N(H) = 0.16 ± 0.02 which is much lower than those found in previous works, and is not different from those of normal classical novae. Adopting the distance 6 kpc, the mass of the ejecta is estimated as 3−9× 10−7 M .
A double-/spl Pi/ stub proximity feed U-slot patch antenna

The design and measured results of a rectangular U-slot patch antenna proximity fed by a double-/spl Pi/ stub feed are described. Using approximately 0.09/spl lambda/ of air gap separating the upper and lower dielectric, an impedance bandwidth of 26% centered at 4.4 GHz and a gain of 6 dBi have been achieved. The proposed antenna is noted to be tolerable to lateral displacement of the feed and produces a better impedance matching than the single /spl Pi/-stub antenna. The radiation patterns obtained are stable across the passband.
Self-sintering-assisted high intergranular connectivity in ball-milled ex situ MgB2 bulks

To understand the mechanisms leading to higher intergranular connectivity in polycrystalline ex situ MgB2 prepared using a pressure-less self-sintering technique, the influence of the initial particle size of the MgB2 powder was investigated. MgB2 bulks sintered at 900 °C for 24 h using ball-milled powders exhibited a network structure with both qualitatively and quantitatively improved intergranular couplings. The connectivity calculated using normal-state transport measurements reached a high value of ∼40%, which is comparable to that of MgB2 bulks fabricated via Mg diffusion or high-pressure-assisted processes. Moreover, the sintering time required to achieve a reasonably high connectivity of 25–30% was less than 1 h. Notably, microstructural analyses confirmed the formation of intergranular necks and grain boundaries during the early stage of sintering. These results suggested self-sintering of the ball-milled MgB2 bulks proceeded much more rapidly than those sintered using an MgB2 powder without ball-milling. Increased intergranular contact points and decreased gap length between grains in green compact are assumed to be the origins for the stimulated self-sintering and corresponding increase in the electrical connectivity.
Does the wall number of carbon nanotubes matter as conductive transparent material

As electrically conductive and optically transparent thin coating material, double-wall carbon nanotube network was found to have better transparency-conductance performance as compared with single-wall carbon nanotube (SWNT) and multiwall carbon nanotube (MWNT). The electronic transportability and optical properties of the SWNT films can be altered by chemical modification of thionyl chloride. Additionally, the conductance-temperature dependence analysis revealed that variable-range hopping mechanism dominates the conductance of few wall nanotube mats while fluctuation-assisted tunneling plays a more important role in that of MWNT films.
Mechanical behavior and fracture of graphene nanomeshes

We study the mechanical behavior and fracture of graphene nanomeshes (GNMs) consisting of hexagonal lattices of unpassivated circular pores based on molecular-dynamics simulations of uniaxial tensile deformation tests. We analyze the GNMs' mechanical response as a function of their porosity for porosities up to 80%. We find that the fracture strain exhibits a minimum at a porosity ∼15%, which marks the onset of a transition in the mechanical behavior of the nanomeshes; beyond this critical porosity, the GNM ductility increases and the toughness remains practically constant with increasing porosity. The mechanism of crack initiation and propagation is characterized in both cases of mechanical response.
Influence of precision inertial systems on astronomical observations

The incorporation of precision inertial control on LST could exert a strong influence on the philosophy of and techniques for carrying out astronomical observations. In conjunction with a fine guidance star sensor, the inertial reference unit (IRU) described herein could easily expand LST capability to include observations such as (1) tracking of solar system objects, including specific points of interest on the planets; (2) rapid repositioning of scanning sensors on distributed objects such as nebulae and galaxies; (3) carrying out unified star catalog measurements to eliminate the overlap problem which exists in all ground procedures; and (4) carrying out various astrometric measurements with 'real time' data reduction capability.
A Spectral General Circulation Model Using a Piecewise-Constant Finite-Element Representation on a Hybrid Vertical Coordinate System

Abstract A numerical scheme for the vertical discretization of primitive equations in a generalized pressure-type coordinate is developed through application of the Galerkin formalism with piecewise-constant finite elements: this methodology affords an elegant—and direct—mean of formulating conservative discretization schemes without the arbitrariness that usually characterizes the development of finite differences. The form of the resulting semidiscrete equations is equivalent to some second-order accurate finite-difference approximation to the continuous equations. Flexibility of this scheme in the choice of different layers for projecting the thermodynamic and momentum variables effectively allows for staggering of these variables in the vertical. Numerical integrations performed with this scheme at various vertical resolutions have revealed the sensitivity of the simulated circulation to resolution in the lower stratosphere. We found that application of the “lid” upper boundary condition at a finite h.
Curvature-based approach to point correspondence recovery in conformal nonrigid motion

Abstract This paper describes a novel method for the estimation of point correspondences on a surface undergoing conformal nonrigid motion based on changes in its Gaussian curvature. The use of Gaussian curvature in nonrigid motion analysis is justified by its invariancy towards rigid motion and the type of surface parameterization. Input to the algorithm is the set of 3D points before and after the motion. We deal with a restricted class of nonrigid motion called conformal motion. In conformal motion, the stretching is equal in all directions, but different at different points. Small motion assumption is utilized to hypothesize all possible point correspondences. Curvature changes are then computed for each hypothesis. Finally, the error between computed curvature changes and the one predicted by the conformal motion assumption is calculated. The hypothesis with the smallest error gives point correspondences between consecutive time frames. The algorithm requires calculation of the Gaussian curvature at points on surface before and after the motion. It also requires computation of the coefficients of the first fundamental form at points on surface before the motion. Estimation of point correspondences and stretching can also be refined so as to reduce the error introduced by sampling. Simulations are performed on an ellipsoidal data to illustrate performance and accuracy of derived algorithms. Then, the proposed algorithm is applied to volumetric CT data of the left ventricle (LV) of a dog′s heart. Stretching of the LV wall during its expansion and contraction phases is depicted along with the estimated point correspondences. Stretching comparisons are made between the normal and abnormal LV.
A Low-Noise Seven-Channel DC SQUID Magnetometer for Brain Research

The design, construction, and performance of a high-sensitivity DC SQUID magnetometer, covering a circular area of 93 mm diameter, is described. The device, now used routinely in our brain research, comprises seven asymmetric first-order gradiometers, located on a spherical surface of 125 mm radius and with the symmetry axis tilted 30° in respect to the vertical. The overall field sensitivity of the system, measured inside our magnetically shielded room, is 5 – 6 fT/√Hz ,mainly caused by thermal noise in the radiation shields of the dewar.
High performance continuous wave 1.3 μm quantum dot lasers on silicon

We demonstrate record performance 1.3 μm InAs quantum dot lasers grown on silicon by molecular beam epitaxy. Ridge waveguide lasers fabricated from the as-grown material achieve room temperature continuous wave thresholds as low as 16 mA, output powers exceeding 176 mW, and lasing up to 119 °C. P-modulation doping of the active region improves T0 to the range of 100–200 K while maintaining low thresholds and high output powers. Device yield is presented showing repeatable performance across different dies and wafers.
Package ‘groupedSurv’

Maintainer Alexander Sibley <dcibioinformatics@duke.edu> Description These 'Rcpp'-based functions compute the efficient score statistics for grouped time-toevent data (Prentice and Gloeckler, 1978), with the optional inclusion of baseline covariates. Functions for estimating the parameter of interest and nuisance parameters, including baseline hazards, using maximum likelihood are also provided. A parallel set of functions allow for the incorporation of family structure of related individuals (e.g., trios). Note that the current implementation of the frailty model (Ripatti and Palmgren, 2000) is sensitive to departures from model assumptions, and should be considered experimental. For these data, the exact proportionalhazards-model-based likelihood is computed by evaluating multiple variable integration. The integration is accomplished using the 'Cuba' library (Hahn, 2005), and the source files are included in this package. The maximization process is carried out using Brent's algorithm, with the C++ code file from John Burkardt and John Denker (Brent, 2002).
Stochastic models of intracellular transport

The interior of a living cell is a crowded, heterogenuous, fluctuating environment. Hence, a major challenge in modeling intracellular transport is to analyze stochastic processes within complex environments. Broadly speaking, there are two basic mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually in the form of adenosine triphosphate hydrolysis, and can be direction specific, allowing biomolecules to be transported long distances; this is particularly important in neurons due to their complex geometry. In this review a wide range of analytical methods and models of intracellular transport is presented. In the case of diffusive transport, narrow escape problems, diffusion to a small target, confined and single-file diffusion, homogenization theory, and fractional diffusion are considered. In the case of active transport, Brownian ratchets, random walk models, exclusion processes, random intermittent search processes, quasi-steady-state reduction methods, and mean-field approximations are considered. Applications include receptor trafficking, axonal transport, membrane diffusion, nuclear transport, protein-DNA interactions, virus trafficking, and the self-organization of subcellular structures.
A theory of normal moveout

Three geophysical principles are shown to be sufficient to determine the most general, practical normal moveout (NMO) equation. The principles are reciprocity in a common midpoint (CMP) gather, finite slowness, and exact constant velocity limit. The resulting equation is the shifted hyperbola NMO equation that has three parameters. Comparisons at both near and far offsets between the shifted hyperbola NMO equation and the results for layered media assign geophysical meaning to the parameters. Two of the parameters, zero offset time and NMO velocity, are constants and control the very near offset behavior. The third parameter is dimensionless and controls the far offset behavior of the NMO curve, but it may be a function of offset so as to exactly fit any traveltime curve. The parameters may be found by a linear least‐squares fit to data. The theory applies to all offsets for nonturning wave reflections in an isotropic earth for both P‐waves and converted (P - SV) waves.
On the Hermitian Optical Phase Operator

Abstract It has long been believed that no Hermitian optical phase operator exists. However, such an operator can be constructed from the phase states. We demonstrate that its properties are precisely in accord with the results of semiclassical and phenomenological approaches when such approximate methods are valid. We find that the number-phase commutator differs from that originally postulated by Dirac. This difference allows the consistent use of the commutator for inherently quantum states. It also leads to the correct periodic phase behaviour of the Poisson bracket in the classical regime.