New physical model to explain logarithmic time dependence of data retention in flash EEPROM

Data retention after program/erase (P/E) cycles is one of the most important reliability issues in a flash EEPROM. Electron detrapping is the main cause of data leakage in the state-of-the-art flash EEPROM. The log(t) dependence of ΔV_th is a unique aspect of the electron detrapping. To explain log(t) dependence, we have assumed that after electron detrapping, the positive-ionized trap reduces the probability of electrons in the influence area being emitted from their site. Based on this assumption, we have proposed a model of detrapping which is consistent with the experimental results.     

Dynamic dielectric response of a quantum wire superlattice in interaction with a nonlocal host medium

We study nonlocality effects of a bulk plasmalike dielectric medium on the plasmon spectrum of a one-dimensional (1D) quantum wire superlattice in interaction with the 3D nonlocal host bulk plasma, by carrying out a closed-form analytic determination of the inverse dielectric function κ for the joint nanostructure system within the random phase approximation (RPA), in which we treat nonlocality of the 1D superlattice in the RPA and that of the bulk medium in the hydrodynamic model. By examining the frequency poles of κ (i.e., the dispersions relations), we show analytically that coupled plasmon modes of the interacting 1D superlattice-3D nonlocal host are damped in high frequencies (damping is pronounced near resonance region) and that nonlocality of the host medium introduces nonlocal low frequency (real) modes into the spectrum, which have cutoff frequencies for finite wave vector values. In order to describe the impact of nonlocality effects more clearly, we also examine the spectrum numerically.     

Approximating long-memory DNA sequences by short-memory process

This paper analyzes the approximation of a general long-memory ARFIMA (p,d,q) process by a short-memory ARMA(1, 1) process. To validate this approximation, a mean square error forecast criterion is considered, and the calculation of the mean square error between the observation X_t+l of an ARFIMA process and the l-step-ahead forecast of the ARMA(1, 1) process is presented. The performance of the ARMA(1, 1) approximation to an ARFIMA model is illustrated by using an application to a DNA sequence of orf virus. This paper gives some theoretical justification on the mean square error forecast criterion based on a selected ARMA(1, 1) model when compared to the general ARFIMA(p,d,q) process. The paper also provides a DNA sequence of orf virus analysis when the time series is originated from the tangent values of the Chaos Game Representation coordinates for each nucleotide. The conclusions of this paper work well because the estimator value of d is small (). The paper also gives the other parameter estimate of the fitted ARFIMA (0, d, 1) model and one-step predictions using ARMA(1, 1) model.     

Nonlocal instantons and solitons in string models

We study a class of nonlocal systems which can be described by a local scalar field diffusing in an auxiliary radial dimension. As examples p-adic, open and boundary string field theory are considered on Minkowski, Friedmann–Robertson–Walker and Euclidean metric backgrounds. Starting from distribution-like initial field configurations which are constant almost everywhere, we construct exact and approximate nonlocal solutions. The Euclidean p-adic lump is interpreted as a solitonic brane, and the Euclidean kink of supersymmetric open string field theory as an instanton. Some relations between solutions of different string theories are highlighted also thanks to a reformulation of nonlocal systems as fixed points in a renormalization group flow.     

Phase modulation of charge density wave around a short-range potential by the Aharonov-Bohm effect

The analytic result of the Aharonov-Bohm effect for its influence on the oscillation of a two-dimensional charge density around a short range potential is given. Without losing generality, the cases of δ-function and hard disc potentials were examined. Numerical calculations show that the interferences among quantum particles are greatly influenced by the nonlocal effect, which leads to the modulation of phase and amplitude of the oscillation of charge density. Since the presence of a nonlocal influence of the Aharonov-Bohm effect on charged particles is universal, the results in the specific potentials examined are expected to appear also in other general systems which may be beneficial to the study of nanotechnology.     

Casimir Force Between Two Spatially Dispersive Dielectric Parallel Slabs

We investigate the Casimir force F between two parallel spatially dispersive semiconductor slabs, whose dielectric response function accounts for nonlocal effects. Nonlocal effects are induced by the presence of excitonic transitions in the semiconductor slabs for which our studies consider the A _n?=?1 exciton in CdS and the Z₃1s one in CuCl. In order to explore the nonlocal effects in the Casimir force, we first calculate the S and P polarized reflection coefficients of the excitonic slabs then we use them in the functional form of F. The slabs are considered as homogeneous, and nonhomogeneous media where the latter is a periodic system having a unit cell with period d. We present numerical calculations of F as a function of the vacuum gap of width L between the slabs, different slab thicknesses, and periods. Comparisons between numerical results obtained by using a nonlocal and a local theory show that the nonlocal effects are more significant at short separations of the slabs. F suffers a small decrease as a consequence of the energy absorption induced by the excitons.     

Synchronization defect lines in complex-oscillatory target waves

It is well known that one of key features of spiral waves in complex-oscillatory media is the appearance of synchronization defect lines, across which the phase of the oscillation changes by multiplies of 2π. In this Letter, we report the appearance of synchronization defect lines in target waves in complex-oscillatory media by studying a model of two-dimensional Rössler reaction-diffusion system subject to an appropriate periodic force in a small region of the center of domain. The geometric structure and stability of the defect lines are studied.     

A new protocol for constructing nonlocal n-qubit controlled-U gates

We present a new protocol for constructing a nonlocal n-qubit controlled-U gate. In this protocol, no prior sharing of entanglement is needed and only one ancilla qubit is sent once from one party to another. Thus, the present protocol is very efficient for performing a nonlocal multiqubit controlled-U gate, which is important to network quantum information processing and communication.     

Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B2

Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R₀) calculated by using Foster relation is 32.13 Å, and as it is less than 50 Å, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B₂ directly from pharmaceutical tablets.     

Electrochemical properties of electrosynthesized TiO2 thin films

Titanium dioxide (TiO₂) thin films prepared by cathodic electrodeposition on indium-tin-oxide coated glass substrates from simple aqueous peroxo-titanium complex solutions have been studied as a function of sintering temperature (25-500 °C). The films crystallized in to anatase phase at relatively low temperature (300 °C). Electrochemical properties of amorphous and anatase films were investigated by cyclic voltammogram (CV) in lithium ion containing organic electrolyte. All the films were found to show reversible electrochemical properties upon Li⁺ ion intercalation. The effects of sintering temperature on the crystallinity and consequently on the electrochemical properties of TiO₂ has been discussed.     

Determination of sodium migration in sol-gel deposited titania films on soda-lime glass with r.f. glow discharge optical emission spectroscopy

Transparent TiO₂ films were produced via sol-gel spin and dip-coating techniques. Soda-lime glass (SLG) and SiO₂ precoated glass were used as substrates. The thin films were characterized by X-ray diffraction (XRD), X-ray reflectometry (XRR), optical profilometer and glow discharge optical emission spectroscopy (GD-OES). Na migration was detected in the amorphous TiO₂ films which are deposited on SLG substrates. In order to prevent sodium migration a barrier layer was introduced between TiO₂ film and glass. The beneficial role of this barrier layer on alkali migration is verified and the mechanism of prevention of migration is proposed relying on the results of GD-OES depth profile measurements.     

Incoherent solitons in strongly nonlocal media: The coherent density theory

We study the properties of one dimension incoherent accessible solitons in strongly nonlocal media with noninstantaneous Kerr nonlinearity. Following the coherent density theory, we obtain an exact solution of such incoherent solitons. The spatial width of the incoherent solitons is related to the incoherent angular power spectrum θ₀ as well as the incident power. The evolution properties of the intensity profile and the coherence characteristics are also discussed in detail when the solitons undergo periodic harmonic oscillation.     

Elliptic incoherent spatial solitons and their interactions in strongly nonlocal media with an anisotropic nonlocality

We investigate the propagation and interaction of elliptic incoherent spatial solitons (EISS) in strongly nonlocal kerr media with an anisotropic nonlocality based on the coherent density approach. An exact analytical solution of such EISS is obtained; the results show that such EISS can form with both isotropic and anisotropic coherence. Moreover, we find that the interaction properties of EISS are very similar to that of their coherent counterpart. Some numerical examples are presented and pertinent physics features are addressed.     

Padé approximant for refractive index and nonlocal envelope equations

Padé approximation is superior to Taylor expansion when functions contain poles. This is especially important for response functions in complex frequency domain, where singularities are present and intimately related to resonances and absorption. Therefore, we introduce a rational Padé approximant for the complex medium refractive index n(ω). The approximant is calculated using only local information of medium dispersion properties close to a carrier frequency ω₀. In return it typically offers an accurate global representation of medium dispersion and absorption. Moreover, the fulfillment of the causality principle and the Kramers-Kronig relation can be established. In practice, our results are relevant if n(ω) is known only for ω?ω₀ whereas optical field is spectrally broad such that (i) the resonance absorption becomes important and (ii) a traditional polynomial dispersion operator diverges and induces huge errors. As an exemplary application we use the approximant to derive a nonlocal envelope model for ultrashort pulses. The model provides a natural bridge between the commonly used local envelope equations and the most general non-envelope models operating directly with the electric field.     

Numerisch genaue Lösungen des nichtlokalen Schalenmodells

The nonlocal Schrödinger-equation has been solved in the shell model case with a kernel-function, which is well known from optical model calculations. Now in the eigenvalue region the energies, as well as the wave-functions, of the exact and the approximate nonlocal calculations (E andE ₀) differ slightly on the average. The exact solutions show in general larger energy-level distances. Although these differences are small, fitting of experimental neutron binding-energies requires nevertheless a relatively big change of the set of physical parameters; the exact nonlocal calculations tend to larger potential depthV and smaller radius constantr ₀ than the approximate nonlocal ones. For the wave-functions (Φ andΦ ₀) it can be shown that an application of the Perey-effect leads to a wrong result in the shell model case. Here the difference function shows two inflection points, whereas there is only one in the optical model. The form of nuclear matter distribution thus becomes more potential-like. The eigenfunctions of the exact nonlocal calculation are orthogonal, whereas the local equivalent ones are not.     

Nonlocal gravitational models and exact solutions

A nonlocal gravity model with a function f (□^?1 R), where □ is the d’Alembert operator, is considered. The algorithm, allowing to reconstruct f(□^?1 R), corresponding to the given Hubble parameter and the state parameter of the matter, is proposed. Using this algorithm, we find the functions f(□^?1 R), corresponding to de Sitter solutions.     

Melt processing of alumina in graphite ambient for dosimetric applications

Carbon-doped alumina samples were prepared by a simple process involving melting of polycrystalline alumina powder in graphite environment. The melting was carried out using an electron gun of a vacuum deposition system meant for deposition of thin films. The samples showed excellent thermoluminescence (TL) and optically stimulated luminescence (OSL) response in the dose range 3 mGy to 1 Gy. Defect centers in the prepared material, as determined by excitation spectra, were found to be similar to those of commercial α-Al₂O₃:C single crystals. Samples were found to be suitable for radiation dosimetry, with a detection threshold of 50-μGy. Fading in the dark has been found to be<2% for a period of 2 months at room temperature. The variation in OSL response among the samples processed under similar conditions was found to be within ±14%.     

Nonlocal effects in ellipsometry of metallic films on metals

A simple but exact generalization of optical surface response formalism beyond the long wavelength approximation (LWA) is developed and evaluated within the hydrodynamic approximation for a nonlocal three layer model describing a metal film between a dielectric and a metallic substrate. In the LWA an explicit analytical formula for the ellipsometry ratio ρ = r_p/r_s in terms of bulk optical constants of the layer materials is given. Model calculations show that classical optics can reproduce nonlocal results only with a strange effective dielectric function of the film reflecting substrate properties up to large film thickness.     

Additive Temporal Coloured Noise Induced Eckhaus Instability in Complex Ginzburg-Landau Equation System

The effect of additive coloured noises, which are correlated in time, on one-dimensional travelling waves in the complex Ginzburg-Landau equation is studied by numerical simulations. We found that a small coloured noise with temporal correlation could considerably influence the stability of one-dimensional wave trains. There exists an optimal temporal correlation of noise where travelling waves are the most vulnerable. To elucidate the phenomena, we statistically calculated the convective velocities Vg of the wave packets, and found that the coloured noise with an appropriate temporal correlation can decrease Vg, making the system convectively more unstable.     

The nucleon-nucleon potential in the nonrelativistic quark model

The effective nucleon-nucleon potential is presented in the model with two three-quark clusters. The potential is nonlocal and nonadiabatic.The shape of the local adiabatic part strongly depends on the definition of the effective potential and on the choice of the subspace used in the calculation. To get some information about the repulsive core and the weak attractive part, one has also to take into account the nonlocal terms. Then for commonly used quark-quark interactions, a repulsive core is obtained, which is not very sensitive to the choice of the parameters of the quark-quark interaction; beyond the core there is a weak attraction.The trial function is constructed as a mixture of NN, ΔΔ and different coloured baryon-coloured baryon configurations. The trial function is an antisymmetric colour singlet with isospin T = 0, spin S = 1 and orbital angular momentum L = 0.