Miracle-dz/UniFAR-FTUs huggingface dataset:
Does an X-Ray Photon Really Generate a Charge Cloud with an Asymmetric Shape?

An X-ray photon produces a finite-sized primary charge cloud inside a charge-coupled device (CCD). Its shape is determined to be asymmetric using a mesh experiment. It is elongated in the direction perpendicular to the charge transfer direction. We checked whether or not the asymmetry of the charge cloud shape was due to the experimental setup. The geometrical shape of the mesh holes is confirmed to be symmetric by a Scanning Electron Microscope (SEM). A new method is introduced to quantitatively measure the effective size of the mesh hole for the X-rays. The geometrical diameter of the mesh hole is 3.4 µm while the effective diameter of the mesh hole is 3.9± 0.3 µm for Al-K X-ray photons (1.5 keV) and 4.0±0.3 µm for Mo-L X-ray photons (2.3 keV), respectively. These values are consistent with that taking into account the diffraction of X-rays. We conclude that the asymmetry of the primary charge cloud generated inside the CCD is due not to the experimental setup but to the asymmetry of the electric field inside the CCD.
Martingale Methods in Financial Decision-Making

This paper presents an introduction to martingale theory by stating some basic definitions and presenting some probabilistic examples. Afterwards, we illustrate the use of martingale methods in economics and finance. In particular, we present applications of martingale methods in futures pricing, in stochastic present discounted value of capitalization and in intertemporal stochastic optimization. The main conclusion of this paper is that martingale methods have been applied as useful techniques in decision-making problems in economics and finance.
Thin Film Diamond Sensor Technology

Modern thin film sensor technology imposes stringent demands upon material quality, highly qualified downstream process technologies, device performance and integrity. Since the earliest stages of its development, crystalline thin film diamond has been promoted as a semiconductor material for high power, high frequency or high temperature electronics. These predictions have been based largely on early experiments made with small single crystal stones. As the properties of thin film diamond are beginning to match up with those of single crystal diamond the real scope for diamond in electronics is being realised. This paper reviews some of the developments made in thin film dia mond sensors at AEA Technology. The development of chemical vapour deposition processes for manufacturing wafer scale insulating and doped semiconducting diamond are reviewed. The development of downstream process technologies such as device delineation and contact technology are discussed. Finally some demonstration devices are presented which illustrate the material issues that have arisen in diamond sensor technology and its potential.
Critical currents in graphene ribbon Josephson's junctions

The rapidly advancing technology of nanodevices has led to the production of smaller and smaller structures often called mesoscopic systems. These devices are large on the atomic scale, but sufficiently small that the electron wave function is coherent over the entire sample: the condition for coherence is that the electron traverses the wire without undergoing any collision with phonons or other electrons. Because the electron can lose energy and equilibrate with heat bath only via inelastic collisions, it is necessary to re-examine the conventional concept of energy dissipation in a resistor. We study the way in which the superconducting correlations are induced in graphene ribbon when it is placed between two superconductors, how such correlations may depend on complex edge structure of the ribbon, on the geometry of the experimental set-up and what is the role of Andreev's reflection in Josephson's effect at superconducting contacts.
Energy budgets in collisionless magnetic reconnection: Ion heating and bulk acceleration

This paper investigates the energy transfer in the process of collisionless antiparallel magnetic reconnection. Using two-dimensional hybrid simulations, we measure the increase of the bulk and thermal kinetic energies and compare it to the loss of magnetic energy through a contour surrounding the ion decoupling region. It is shown, for both symmetric and asymmetric configurations, that the loss of magnetic energy is not equally partitioned between heating and acceleration. The heating is found to be dominant and the partition ratio depends on the asymptotic parameters, and future investigations will be needed to understand this dependence.
Piezoelectric shear force detection: A geometry avoiding critical tip tuning fork gluing

A technique for controlling the tip–sample distance in near-field optical microscopes is presented. It consists of mechanically exciting a fiber tip inserted without any adhesive between the two prongs of a high Q-piezoelectric tuning fork. The detection of the shear forces is classically achieved by measuring the decrease of the dithering amplitude when the tip approaches the surface. This simple setup greatly simplifies tip replacement and its resonance frequency tuning.
On the strict hyperbolicity of the Buckley-Leverett equations for three-phase flow in a porous medium

In this paper the mathematical properties of three-phase flow are discussed. From the properties of the relative permeabilities on the boundary of the three-phase region, it is argued that the system is strictly hyperbolic but with a nonremovable elliptic region in the interior. The nonremovable elliptic region may be reduced to a point (umbilic point) by continuously deforming the relative permeability functions in the interior of the three-phase region. It is well known that elliptic regions lead to severe instabilities in the saturations.Usually it is assumed that the relative permeability of water only depends on the water saturation and that the relative permeability of gas only depends on the gas saturation, whereas the relative permeability of oil depends on all the saturations (Stone’s assumption). With this assumption it is possible to be more precise. If three specified curves intersect at one common point and the isoperms of the relative permeability of oil are concave, then the system is stric.
Terahertz dielectric properties of high-resistivity single-crystal ZnO

resistivity single-crystal ZnO. 7 ZnO is considered as a promising material for terahertz optics because of a number of advantages: Ease in fabrication, wide band gap, rather high mobility and resistivity, and transparency in a broad frequency range. The experimental result indicated that the high breakdown electric field enables ZnO to be an intriguing semiconductor in high-power terahertz generation. It is essential to explore the detailed optical and dielectric properties of ZnO in the broad terahertz frequency region. In this letter, the far-infrared optical properties and the complex dielectric function of high-resistivity single-crystal ZnO are experimentally characterized by use of terahertz time-domain spectroscopy THz-TDS. The measured refractive index, power absorption, and complex dielectric function are compared with the pseudo-harmonic model. In the scope of our frequency range from 0.3 to 3.5 THz, the experimental data agree well with theoretical fitting. The measured power absorption, which increased approximately quadratically with frequency, was found to be dominated by the transverse optical TO E1 phonon at frequency TO/2 12.42 THz. The ZnO sample is an undoped 5 mm 5m m0.5mm-thick freestanding single crystal obtained from MTI Corporation, USA. The both-side polished sample has crystal orientation 0001 with c-axis perpendicular to the surface. Hydrothermal growth method was used to fabricate the wurtzite high-resistivity ZnO with purity higher than 99.99%. The ZnO crystal was characterized with a photoconductive switch-based THz-TDS system which has an 8-F configuration and an useable bandwidth extending from
Investigation of the Role of Polymer on the Delay of Tip Vortex Cavitation

Cavitation tunnel measurements have shown tip vortex cavitation inception is delayed when polymers are injected from the hydrofoil tip. Experiments with polymers have also shown that the polymers cause the cavitation to become more violent. To better understand the role of polymer in the delay of tip vortex cavitation, a theoretical analysis of tip vortex cavitation inception in pure water and in polymer solution is presented
Long run and transient analysis of a double EWMA feedback controller

The “predictor-corrector” feedback controller is a popular adjustment scheme proposed for the quality control of certain semiconductor manufacturing process steps. This controller is based on a double Exponentially-Weighted Moving Average (EWMA) scheme; thus the performance of the closed-loop system depends on the two weight parameters of the EWMA equations. In this paper, the conditions the weights must satisfy to ensure closed-loop stability are discussed. The optimal determination of the controller weights depends on a trade-off between long-run process variance and transient bias performance. It is shown that small weights, although they can guarantee stability, may result in severe, long transients, an important concern if fabrication is in small batches. An optimization model for finding the controller weights is given and numerically solved. An extension of this type of controllers to the multiple controllable factor case is described. The performance of the controller is illustrated with an application to Chemical Mechanical Polishing, a critical semiconductor manufacturing step.
Aspherical wavefront measurements: Shack-Hartmann numerical and practical experiments

We consider an application of the original Hartmann method to bundles of rays generated by a Shack-Hartmann analyser. Absolute Shack-Hartmann measurements of converging wavefronts with the nominal method of collimating optics, used to locate the real image of a pupil on a microlens array, are not applicable when the wavefront asphericity is so strong that real subimages produced by individual lenslets of the array are no longer simultaneously focused at a common plane. As examples of strongly aspherical wavefronts we consider reflected beams obtained when testing large aspherical mirrors at their centre of curvature. Analytic formulae are applied to several instances and a ray-tracing program for a large-diameter strongly paraboloidal liquid mirror suggests that the Shack-Hartmann method could, however, be used by combining several cross sections of interlaced rays located downstream from the microlens array. In order to estimate how precisely subbundles of rays may be reconstructed from several cross sections we performed a small-scale experiment to measure an aspherical wavefront departing by more than from a best-fit sphere. A microlens array samples 2000 subareas per pupil. Eleven cross sections, corresponding to as many real and virtual subbundles of rays, are obtained upstream and downstream from an array using a relay optics to give enlarged real images on photographic film. We measured 57 subbundles and verified the straight line propagation of light to within a precision on negatives corresponding to a local 45 nm wavefront uncertainty. The uncertainty value for calibration using additional cross sections upstream and downstream from the microlens array amounts to 8 nm. We conclude from these numerical and practical experiments that the Shack-Hartmann method may be modified in order to measure strongly aspherical wavefronts, including reflected wavefronts obtained from centre-of-curvature testing for large aspheric mirrors.
Optimal pricing and ordering policy for non-instantaneous deteriorating items under inflation and customer returns

This paper deals with an economic production quantity inventory model for non-instantaneous deteriorating items under inflationary conditions considering customer returns. We adopt a price- and time-dependent demand function. Also, the customer returns are considered as a function of both price and demand. The effects of time value of money are studied using the Discounted Cash Flow approach. The main objective is to determine the optimal selling price, the optimal replenishment cycles, and the optimal production quantity simultaneously such that the present value of total profit is maximized. An efficient algorithm is presented to find the optimal solution. Finally, numerical examples are provided to solve the presented inventory model using our proposed algorithm, which is further clarified through a sensitivity analysis. The results of analysing customer returns provide important suggestions to financial managers who use price as a control to match the quantity sold to inventory while maximizing revenues. The paper ends with a conclusion and an outlook to future studies.
A relation between massive scalar field in AdSd+1 and diffusion in channels

It is shown that, when the diffusion coefficient is a constant and is taken a particular family of channels, the Fick-Jacobs equation is invariant under conformal symmetry. In addition, using the diffusion coefficient and the geometric parameters of the channels, a representation for the conformal algebra is obtained. Furthermore, it is found that for these systems the Fick-Jacobs equation is equivalent to the Schrödinger equation for the 1-dimensional conformal quantum mechanics. Moreover, using this equivalence, it is found a relation between a massive scalar field equation in AdSd+i background and Fick-Jacobs equation, where the geometric parameter of the channels and the geometric parameters of AdSd+1 are identified.
Soft X-ray emission from 2A 0311-227, an AM Herculis-type system

The low energy detectors on board the HEAO 1 satellite have observed a variable, soft X-ray source consistent with the location of 2A 0311--227. The maximum observed intensity is approx.2 x 10/sup -11/ ergs cm/sup -2/ S/sup -1/ (0.18--0.43 keV) and the temperature must be <10/sup 7/ K. The source is interpreted as a member of the AM Herculis class on the basis of the optical identification with a magnetic binary system.
An enhanced coupling nonlinear control method for bridge cranes

The present study suggests an enhanced coupling non-linear control approach for both cart positioning and load swing elimination control of underactuated bridge cranes. The significant feature of the proposed method is its superior control performance as well as its strong robustness over different/uncertain cable lengths that are the major factor influencing load swing. Owing to the underactuated nature, the load swing can merely be damped out by the cart motion. Inspired by this inherent mechanism and also motivated by the desire to achieve an improved control performance, we enhance the coupling behaviour between the cart movement and the load swing by introducing a new composite signal, and on this basis, propose a non-linear control law. Lyapunov-based mathematical analysis is implemented to support the theoretical derivations. To verify its control performance, both numerical simulation and hardware experiment results are included to illustrate that the proposed method can achieve superior control results and admit strong robustness with respect to different/uncertain cable lengths and external disturbances.
EPOL: the exoplanet polarimeter for EPICS at the E-ELT

EPOL is the imaging polarimeter part of EPICS (Exoplanet Imaging Camera and Spectrograph) for the 42-m E-ELT. It is based on sensitive imaging polarimetry to differentiate between linearly polarized light from exoplanets and unpolarized, scattered starlight and to characterize properties of exoplanet atmospheres and surfaces that cannot be determined from intensity observations alone. EPOL consists of a coronagraph and a dual-beam polarimeter with a liquid-crystal retarder to exchange the polarization of the two beams. The polarimetry thereby increases the contrast between star and exoplanet by 3 to 5 orders of magnitude over what the extreme adaptive optics and the EPOL coronagraph alone can achieve. EPOL operates between 600 and 900 nm, can select more specific wavelength bands with filters and aims at having an integral field unit to obtain linearly polarized spectra of known exoplanets. We present the conceptual design of EPOL along with an analysis of its performance.
Localisation and tracking of multiple unknown objects in real environments

The Letter presents a real-time surveillance system able to localise and track multiple unknown objects (e.g. trunks, trash compactors, etc.) moving simultaneously in a sanitary landfill. Elementary features of moving image areas are used for object localisation, and a network of extended Kalman filters is applied for multiple object tracking.
Perturbed polariton spectra in optically damaged LiNbO3

Abstract We have performed experimental measurements and quantitative analyses of the influence of optical damage in LiNbO3 upon the polariton spectra. The results show that the principal spectral effect of optical damage is equivalent to a static electric field perpendicular to the crystallographic C3 axis. At T = 100K optical damage levels of 5 KW-hr/cm2 are equivalent to static electric fields of 40 KV/cm applied in the crystallographic y-direction. The analysis provided includes only a single parameter and accounts for the frequencies and intensities of the “forbidden” spectral lines [E(TO) and E(LO) appearing in geometries for which only A1(TO) are permitted. ] This agrees with the conclusion of Chen [J. Applied Phys. 40, 3389 (1969)] that charge diffusion is primarily perpendicular to the polar axis, not along it. These electric fields and charge displacements perpendicular to c are presumably metastable.
The simulation of crack opening–closing and aggregate interlock behaviour in finite element concrete models

The ability to model crack‐closure behaviour and aggregate interlock in finite element concrete models is extremely important. Both of these phenomena arise from the same contact mechanisms, and the advantages of modelling them in a unified manner are highlighted. An example illustrating the numerical difficulties that arise when abrupt crack closure is modelled is presented, and the benefits of smoothing this behaviour are discussed. We present a new crack‐plane model that uses an effective contact surface derived directly from experimental data and which is described by a signed‐distance function in relative‐displacement space. The introduction of a crack‐closure transition function into the formulation improves its accuracy and enhances its robustness. The characteristic behaviour of the new smoothed crack‐plane model is illustrated for a series of relative‐displacement paths. We describe a method for incorporating the model into continuum elements using a crack‐band approach and address a previously overlooked issue associated with scaling the inelastic shear response of a crack band. A consistent algorithmic tangent and associated stress recovery procedure are derived. Finally, a series of examples are presented, demonstrating that the new model is able to represent a range of cracked concrete behaviour with good accuracy and robustness. Copyright © 2015 John Wiley & Sons, Ltd.
Electron transport in quantum wires and its device applications

The electron transport properties in quantum wires are investigated in the ballistic region and the hot-electron region by solving the Boltzmann equations. In the ballistic region, the effect of the scattering due to the surface roughness of a quantum wire on the conductance quantization is studied, and it is made clear how the scattering at the surface roughness destroys the conductance quantization. In the hot-electron region it is shown that the optical-phonon scattering plays an important role in the electron transport, and two types of transport take place as a result. One is electron confinement in a energy region below the optical-phonon energy and the other is electron velocity runaway. With these characteristics the possibility of a velocity modulation field effect transistor is suggested. Finally, a quantum wire resonant tunnelling transistor which works as a kind of multichannel rotational switch is proposed. As an application of this transistor, a switch for a superconducting interconnection network on which signals can propagate without attenuation and distortion is proposed to reduce the number of interconnection lines and also to simplify the circuit configuration.
Numerical analysis of submerged flows for jet grouting

The diffusion of turbulent submerged flows is studied to understand the core mechanism of jet grouting and to enhance the efficiency of treatments. Because of the particularly high speeds, experimental measurement is very difficult, and theoretical relationships found at lower velocities are misleading. The velocity distribution and its relationship with the injection parameters are then obtained, combining experiments, numerical calculations and theory. A numerical finite-volume model simulating the turbulent propagation of submerged jets is initially calibrated using a set of experimental data reported in the literature. This model is used to perform a parametric study, varying the injection parameters within the typical range of jet grouting and evaluating their influence on the velocity distribution. The results of numerical calculations are finally interpreted with a mathematical function relating the velocity distribution to the nozzle diameter, inlet velocity and fluid composition. The effect of in.
A two‐phase sampling scheme with applications to auditing or sed quis custodiet ipsos custodes?

External auditors such as the National Audit Office (NAO) are the final arbiters on the level of error in accounts presented to them by their clients, and the accuracy or otherwise of individual transactions. In coming to a view on the level of error, they are expected to carry out the audit effectively and efficiently, and therefore need to make the best possible use of all the information at their disposal, even when some of the information may not be totally accurate. We consider the particular situation where the NAO is given access to the results of tests on a relatively large random sample of transactions, typically conducted by the client's internal auditors. A two‐phase sampling scheme arises when the NAO subsequently assesses the quality of the client's data by retesting a subsample of these transactions. The paper discusses methodologies for combining the two sets of data to produce optimum estimates of the proportion of transactions in error (the error rate) and of the level of monetary error in the account. Although a maximum likelihood approach yields a relatively straightforward solution to the error rate problem, there is no uniformly optimum way to estimate the monetary error. Three possible methods are proposed, and the results of a series of simulation experiments to compare their performance under a variety of audit conditions is described.