Miracle-dz/UniFAR-FTUs huggingface dataset:
Free space experimental scattering database continuation: experimental set-up and measurement precision

In the present paper, the experimental set-up of Institut Fresnel used to measure the scattered fields of different elongated objects is precisely described. Since the special issue on ‘Testing inversion algorithms against experimental data’, the modifications of this system, outlined here, have mostly been done to improve the synchronization of the apparatuses and the precision of our measurements. Due to a large number of requests from the inverse problem community, it has been decided to add new measurements to the Institut Fresnel's database. All the new targets presented here are two-dimensional inhomogeneous ones. They are made of different dielectrics or are mixing metal and dielectric parts. Both TE and TM polarizations are measured for each target, from 2 to 10 GHz and even 18 GHz for the most complex target. In the first part of this paper the set-up is described precisely. The second part is devoted to the presentation of the targets. Finally, some TE and TM comparisons of measurements and direct problem simulations are shown to accredit our experimental method and to give an idea of the accuracy of these measurements.
NUMERICAL STUDY OF VISCOUS FLOWS PAST A CIRCULAR CYLINDER: APPLICATION OF CHORIN'S METHOD

A. J. Chorin's Method of numerical solution of the Navier Stokes Equations for slightly viscous flows is applied to the problem of an impulsively started circular cylinder. Th~ drag of the cylinder is computed ove r a range of Re = 10 to Re = 10 5 , and the validity of the results is discussed,
Influence of the lattice discreteness on magnetic ordering in nanostructures and nanoarrays

The article attempts to analyze the effect of lattice discreteness on the magnetic ordering in nanostructures and nanoarrays. The discussion starts with a basic introduction of the theoretical methods for the description of the magnetic ordering. Next it is shown that the discrete nature of an atomic lattice may lead to the size‐driven reorientation of magnetization in nanoparticles, i.e., the magnetization direction can be changed by shrinking the lateral size, keeping the thickness fixed. It is demonstrated that in finite nanomagnets the shape anisotropy can be divided into the discrete and continuum contributions. Then the orientation of magnetic domain walls in low‐symmetry objects is discussed. It is shown theoretically that in nanomagnets of monolayer thickness the mechanism of the orientation of domain walls is different from that of bulk systems and is mainly determined by the discreteness of the atomic lattice and the exchange energy. In the last part the theoretical study of magnetostatically interacting nanoarrays is presented. Special attention is paid to the influence of the underlaying lattice symmetry and the higher order multipolar terms on the magnetic ordering. It is demonstrated that the multipole‐multipole interactions lead to an enhancement/decrease of the coercivity in arrays with in‐plane/out‐of‐plane magnetization, respectively. In each section of the manuscript the agreement between the theory and recent experimental results is analyzed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X-ray-excited photoelectron detection using a scanning tunneling microscope.

Detection of x-ray-enhanced electrons emitted by synchrotron radiation with the tip of a scanning tunneling microscope has the potential to open a path to high-resolution microscopy with chemical sensitivity. Nonresonant photoejected electrons typically yield a current background of a few hundred picoamperes at a bare tip. Coating the tip with an insulating boron nitride film can effectively reduce this background. In this configuration, we have quantitatively studied the bias dependent photoelectron collection for tip/sample separations of 400–1600nm, where quantum mechanical tunneling does not contribute.
Solitary waves in excitable systems with cross-diffusion

We consider a FitzHugh–Nagumo system of equations where the traditional diffusion terms are replaced with linear cross-diffusion of components. This system describes solitary waves that have unusual form and are capable of quasi-soliton interaction. This is different from the classical FitzHugh–Nagumo system with self-diffusion, but similar to a predator–prey model with taxis of populations on each other's gradient which we considered earlier. We study these waves by numerical simulations and also present an analytical theory, based on the asymptotic behaviour which arises when the local dynamics of the inhibitor field are much slower than those of the activator field.
Electronic structure, elastic and thermal properties of semiconductor GaX (X = N, P, As, Sb) with zinc blende from first-principles calculation

The band structure, density of states, elastic properties and thermal properties of semiconductor GaX (X = N, P, As, Sb) with zinc blende were calculated by using the first principle plane-wave pseudo-potential methods based on density functional theory (DFT). The band structure and density of states for GaN, GaP, GaAs and GaSb show that GaX compounds are semiconductors with a direct band gap of 1.542, 1.445, 0.34 and 0.257 eV, respectively. The elastic constants and modulus are calculated showing that GaX are mechanically stable and GaN has the largest modulus. The anisotropy factor, internal-strain parameter, shear to bulk modulus and Poisson's ratio are also calculated indicating that GaX exhibit a brittle, anisotropic and plastic character. The dependencies of the Debye temperature, heat capacity, enthalpy, the entropy and free energy on temperature are also investigated. Comparisons with the available experiment and other theoretical calculation show reasonable agreement.
Notice of Retraction Cockroach Swarm Optimization

This paper presents a new bionic algorithm, entitled Cockroach Swarm Optimization (CSO), that is inspired by the social behavior of cockroaches. We construct some models by imitating the foraging behaviors of cockroach, and describe the steps of CSO. Simulation results illustrate that CSO has stronger convergence performance and highly-accuracy optimization results compares with Particle Swarm Optimization (PSO), Chaotic Particle Swarm Optimization (CPSO) and Artificial Fish-swarm Algorithm (AFSA).
Study of gaseous velocity slip in nano-channel using molecular dynamics simulation

Purpose – The purpose of this paper is to investigate the gas flow characteristics in near wall region and the velocity slip phenomenon on the wall in nano-channels based on the molecular dynamics simulation. Design/methodology/approach – An external gravity force was employed to drive the flow. The density and velocity profiles across the channel, and the velocity slip on the wall were studied, considering different gas temperatures and gas-solid interaction strengths. Findings – The simulation results demonstrate that a single layer of gas molecules is adsorbed on wall surface. The density of adsorption layer increases with the decrease of gas temperature and with increase of interaction strength. The near wall region extents several molecular diameters away from the wall. The density profile is flatter at higher temperature and the velocity profile has the traditional parabolic shape. The velocity slip on the wall increases with the increase of temperature and with decrease of interaction strength line.
Generalization of two theorems due to Ramanujan

The aim in this paper is to provide generalizations of two interesting entries in Ramanujan's notebooks that relate sums involving the derivatives of a function φ(t) evaluated at 0 and 1. The generalizations obtained are derived with the help of expressions for the Gauss hypergeometric function 2 F 1(−n, a; 2a+j; 2) for non-negative integer n and j=0,±1, …,±5 given very recently by Kim et al. [Generalizations of Kummer's second theorem with applications, Comput. Math. Math. Phys. 50(3) (2010), pp. 387–402] and extension of Gauss’ summation theorem available in the literature. Several special cases that are closely related to Ramanujan's results are also given.
A novel algorithm based on the domain-decomposition method for the full-wave analysis of 3-D electromagnetic problems

A novel technique based on the domain-decomposition method and frequency-domain finite-difference method is presented for the full-wave analysis of three-dimensional electromagnetic problems. In this method, the original domain is decomposed into sub-domains, Maxwell's equations are then solved in each sub-domain independently, and the global solution is achieved finally by an iterative procedure. It greatly reduces the computational complexity and the memory requirement compared with the conventional finite-difference method and method of moments, etc. To reduce CPU time, some techniques, such as the relaxation iterative algorithm, overlapped domain decomposition, and multimesh resolution are also investigated and adopted to accelerate the algorithm. The validity of this algorithm is verified by numerical examples, including the analysis of a multilayered aperture-coupled patch antenna, the scattering characteristic analysis of conducting pillars, and the S-parameters extraction of the air-bridge discontinuity.
Study on the Methods of Processing the Landsat7 ETM+ Data in the Three Gorge Reservoir Area

Landsat\|7 ETM+ is the latest the landsat series data. Its outstanding advantage is its higher spatial resolution in multi\|spectrum band. It adds a new panchromatic band with a resolution of 15 meters, and enriches information of data. Considering geographic application requests, this paper selects ETM+ data of two scenes of Three Gorge Reservoir Area, studies the processing methods of Landsa7 ETM+ data and compares the results of different processing methods. The study shows that processing the new type remote sensing data——Landsat7 ETM+, with appropriate digital method can obtain remote images with higher spectrum resolution and higher spatial resolution and shows great advantage in application.
Coherent diffractive imaging using short wavelength light sources

Techniques that recover images from diffraction data obtained using coherent short-wavelength light sources are currently under active development for applications in nanotechnology and structural biology. In this review, an outline of paraxial optics is provided in a form that is sufficiently general to incorporate the coherence properties and frequency structure of illumination sources used in diffractive imaging applications. The Fourier phase problem is formulated in the context of imaging algorithms that are designed to obtain uniquely-determined phase distributions from measurements of diffraction data. The properties of several iterative phase retrieval algorithms for both coherent and partially-coherent diffractive imaging applications are presented in a unified formalism, together with a brief discussion of a non-iterative technique. Approaches to diffractive imaging based on Fraunhofer and Fresnel diffraction configurations are compared. Applications are described utilising quasi-monochromatic third-generation synchrotron X-ray sources and polychromatic high-harmonic generation table-top soft X-ray sources. The review concludes with a consideration of proposed applications of diffractive imaging approaches to the determination of biomolecular structures from isolated molecules using fourth-generation X-ray free-electron laser sources.
Phonon localization methods through time and space: Experimental SAW phonon aspects on a cylindrical shell

A transient experimental study of Surface Acoustic Wave (SAW) propagation along a 1D medium as a function of time leads to a 2D space–time signal collection. Previous studies have shown that 3D space‐wave number–frequency representation S(x,k,f) allows the characterization of the space transient aspects of SAW generation [L. Martinez, J. Acoust. Soc. Am. 105, 952 (1999)]. In order to analyze the time transient aspect of phonon propagation, the 3D time–wave Number‐Frequency representation Z(t,k,f) is proposed. The Z(t,k,f) matrix is obtained by short time Fourier transforming each time signal of the 2D time–wave number representation. The Z(t,k,f) representation is used to experimentally investigate SAW generation and propagation around a cylindrical shell (the relative thickness is equal to 0.03) surrounded by water and excited by a pulse (0.1 s duration). For the air filled shell, the Z(t,k,f=const) slices show the time sequence of the continuous flow of incident phonons striking the insonified side of t.
Printed multi-resonant antenna embedding two inductors in radiating strips for internal mobile phone LTE/WWAN operation

In this article, a planar printed antenna for eight-band LTE/WWAN operation applied in the internal mobile phone has been proposed and studied. The presented antenna consists of a feeding strip and a coupling strip, where two chip inductors with different inductances are loaded in place. The desired lower bands of LTE700/GSM850/900 operation can be achieved by the coupling strip loading an inductor of 12 nH and a longer branch loading another inductor of 24 nH in the feeding strip, which provide a quarter-wavelength dual-resonance mode at 720 and 900 MHz. While a quarter-wavelength resonant mode at around 2.95 GHz can be generated by the shorter branch of the feeding strip, and other resonant modes at 1.92 and 2.23 GHz are contributed by the higher-order resonant modes of the long feeding strip and coupling strip, covering the desired upper bands of DCS1800/PCS1900/UMTS2100/LTE2300/2500 operation. In fact, the desired resonant lengths in the lower frequencies can be decreased, and impedance matching can be properly adjusted with the help of the two embedded inductors. Besides, a chip inductor of 2.2 nH is helpful for improving all the bands’ impedance matching. Detailed considerations of the antenna design and main parameters are studied and measured.
The turbulent boundary layer over transverse square cavities

Laser-induced uorescence (LIF) and laser Doppler velocimetry (LDV) are used to explore the structure of a turbulent boundary layer over a wall made up of two-dimensional square cavities placed transversely to the flow direction. There is strong evidence of occurrence of outflows of fluid from the cavities as well as inflows into the cavities. These events occur in a pseudo-random manner and are closely associated with the passage of near-wall quasi-streamwise vortices. These vortices and the associated low-speed streaks are similar to those found in a turbulent boundary layer over a smooth wall. It is conjectured that outflows play an important role in maintaining the level of turbulent energy in the layer and enhancing the approach towards self-preservation. Relative to a smooth wall layer, there is a discernible increase in the magnitudes of all the Reynolds stresses and a smaller streamwise variation of the local skin friction coefficient. A local maximum in the Reynolds shear stress is observed in the shear layers over the cavities.
The Influence of the Track Parameters on Vibration Characteristics of Subway Tunnel

In soft soil areas, such as the Nanjing, it is very important to quantitatively analyze the dynamic behaviors of soft soils during the metro train operation. A nonlinear coupling model of wheel-track and a finite element calculation model of tunnel and soil were established based on the mechanical character of elastic supporting block ballastless track and the actual parameters of Nanjing soft soil. The time-variant vertical acceleration of the rail, the sleepers, and the surface of the tunnel can be calculated by the models, and the frequency dependence acceleration was verified by the fast Fourier transform algorithm. A modified vibration power level for human sensitivity was used to quantify the vibration energy of each part of the system, and the impact of the parameters in the model was evaluated. The results can be applied to the metro design and construction, which also can be the guidance during the tunnel construction.
Exploring stress overshoot phenomenon upon startup deformation of entangled linear polymeric liquids

This work explores the picture associated with stress overshoot during sudden continual (i.e., startup) external deformation of entangled polymeric liquids and proposes a specific scaling form to depict the intermolecular interactions responsible for chain deformation. Following a previously proposed idea that the stress overshoot in startup deformation is a signature of yielding, we search for ingredients that should go into the description of the force imbalance at the yield point and show that the expression for the intermolecular locking force fiml, derived from the characteristics associated with the yield point, can be tested against experiment. New rate-switching experiments support the proposed formula for fiml.
Chapter 8 LIMITS TO TREE GROWTH AND THE “ AGE-RELATED DECLINE ” IN ABOVEGROUND FOREST PRODUCTIVITY

Aboveground net primary productivity (ANPP) generally reaches a maximum early in stand development and gradually decreases as forest stands get older. The mechanism(s) responsible for the decline are not fully elucidated. Both treeand standlevel factors can cause the reduction in ANPP, with those operating at the individual tree level likely to be of principal importance. Opinions are divided on whether tree age or tree size is primarily responsible for the decline in aboveground productivity over time. Settling this debate is a prerequisite to appropriately defining the mechanism(s) underlying the “age-related decline” in forest ANPP. In this paper, we analyzed the literature on the developmental decline in tree growth with particular emphasis on the roles of age and size. We conclude that (a) ageand size-mediated controls of tree growth may be species specific, (b) the decline in aboveground forest productivity might be the result of a combination of factors and (c) an analysis of ageand size-driven mechanisms is necessary to better understand the single and/or combined effects of tree age and tree size on the “age-related decline” in forest ANPP.
Random Gravitational Encounters and the Evolution of Spherical Systems. V. Gravitational Shocks

Numerical calculations of dynamical evolution have been extended to spherical systems in which the stars gain kinetic energy by transient extemal gravitational perturbations, or gravitational shocks. '' Most models were computed for compressive shocks, produced when a cluster crosses the galactic plane; some calculations were made for tidal shocks, produced by passing interstellar clouds or other massive objects. In all models the quasi-static tidal field of the Galaxy was assumed to produce a cutoff in the cluster at the escape radius, r/sub e/. It was assumed that all stars have the same mass and that the density distribution is spherical. Because of the strong central condensation, the shock heating required to avert the collapse of the central core is substantially greater than previously realized, requiring that t/sub sh/ be less than about 5t/sub rh/ , where t/sub rh/ is the reference relaxation time at the mean density within the median radius, r/sub h/, and t/sub sh/ is a parameter which measures the rate of shock heating at the radius r/sub h/. It is doubtful whether shock heating is this strong in any clusters. In the range where t/sub sh/ is between 5t/sub rh/ and about 100t/sub rh/, shock heating can makemore » a dominant contribution to the rate at which stars escape from the system, with an increase in the evaporation probability per star per unit time equal to about 2/t/sub ah/. For open clusters this effect becomes large if r/sub h/ exceeds about 2 pc. Tidal shocks seem to produce about the same effects as compressive shocks. While the computations do not yet include the simultaneous effects both of shock heating and of dynamical relaxation with stars of different masses, the latter process drives the lighter stars out to somewhat greater radii, where the former process should greatly accelerate their escape from the system. (auth)« less
Holographic encoding of fine-pitched micrograting structures in amorphous SiO2 thin films on silicon by a single femtosecond laser pulse

Fine-pitched micrograting structures were holographically encoded in amorphous (a-) SiO2 thin films on silicon wafers by colliding a pair of focused pulses split from a single, mode-locked Ti: sapphire, femtosecond laser. A method enhancing the third-harmonic generation resulting from the nonlinearity of air adjusted the optical paths of the two pulses. Surface-relief-type gratings were formed on SiO2 glasses due to laser ablation when the laser power exceeded more than 0.3 mJ/pulse, while shallow grating structures were imprinted on a-SiO2 thin films by volume compaction (∼3%) when the irradiation power was reduced to ∼50 μJ/pulse. The postirradiation deepening of the valley of the grating structure was possible with chemical etching. The minimal spacing of 430 nm was encoded using the 800 nm laser.
Electromagnetic diffraction in optical systems, II. Structure of the image field in an aplanatic system

An investigation is made of the structure of the electromagnetic field near the focus of an aplanatic system which images a point source. First the case of a linearly polarized incident field is examined and expressions are derived for the electric and magnetic vectors in the image space. Some general consequences of the formulae are then discussed. In particular the symmetry properties of the field with respect to the focal plane are noted and the state of polarization of the image region is investigated. The distribution of the time-averaged electric and magnetic energy densities and of the energy flow (Poynting vector) in the focal plane is studied in detail, and the results are illustrated by diagrams and in a tabulated form based on data obtained by extensive calculations on an electronic computor. The case of an unpolarized field is also investigated. The solution is riot restricted to systems of low aperture, and the computational results cover, in fact, selected values of the angular semi-aperture a on the image side, in the whole range 0 ≤ α ≤ 90°. The limiting case α → 0 is examined in detail and it is shown that the field is then completely characterized by a single, generally complex, scalar function, which turns out to be identical with that of the classical scalar theory of Airy, Lommel and Struve. The results have an immediate bearing on the resolving power of image forming systems; they also help our understanding of the significance of the scalar diffraction theory, which is customarily employed, without a proper justification, in the analysis of images in lowaperture systems.
New Passive Alignment Method of Channel Waveguide Device Using Height Control Spacers

We realized a high coupling efficiency of a laser diode and a channel waveguide device using a new effective alignment method. We adopted the new passive alignment method which involved the use of height control spacers to adjust the vertical position and an image processing technique to adjust the horizontal position. We examined the assembly of a planar module that consists of a laser diode and a channel waveguide device. Coupling efficiency of over 70% of the maximum coupling efficiency was achieved in every sample.