372 research outputs found

    Effect of long-range structural corrugations on magnetotransport properties of phosphorene in tilted magnetic field

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    Rippling is an inherent quality of two-dimensional materials playing an important role in determining their properties. Here, we study the effect of structural corrugations on the electronic and transport properties of monolayer black phosphorus (phosphorene) in the presence of tilted magnetic field. We follow a perturbative approach to obtain analytical corrections to the spectrum of Landau levels induced by a long-wavelength corrugation potential. We show that surface corrugations have a non-negligible effect on the electronic spectrum of phosphorene in tilted magnetic field. Particularly, the Landau levels are shown to exhibit deviations from the linear field dependence. The observed effect become especially pronounced at large tilt angles and corrugation amplitudes. Magnetotransport properties are further examined in the low temperature regime taking into account impurity scattering. We calculate magnetic field dependence of the longitudinal and Hall resistivities and find that the nonlinear effects reflecting the corrugation might be observed even in moderate fields (\mbox{B<10B<10 T})

    A New Method For Increasing the Accuracy of EM-based Channel Estimation

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    It was recently shown that the detection performance can be significantly improved if the statistics of channel estimation errors are available and properly used at the receiver. Although in pilot-only channel estimation it is usually straightforward to characterize the statistics of channel estimation errors, this is not the case for the class of data-aided (semi-blind) channel estimation techniques. In this paper, we focus on the widely-used data-aided channel estimation techniques based on the expectation-maximization (EM) algorithm. This is achieved by a modified formulation of the EM algorithm which provides the receiver with the statistics of the estimation errors and properly using this additional information. Simulation results show that the proposed data-aided estimator outperform its classical counterparts in terms of accuracy, without requiring additional complexity at the receiver

    Many body effects on the transport properties of a doped nano device

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    In this article, we study the effect of electron-electron interaction in a doped nano cluster sandwich between two electrodes. The Hamiltonian of the cluster is written in the tight-binding model and electrodes are described in the wide-band approximation. The GW approximation has been used for the calculation of the exchange-correlation term in the cluster region. Our results showed that in the presence of the electronelectron interaction the transmittance gap increases and current decreases. Also, in a doped nano structure the transmission decreases and many body effect becomes more important. By considering the exchange-correlation in a doped nano cluster in the GW approximation the transmission and current decrease drastically. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2056

    Spectral Analysis of Multi-dimensional Self-similar Markov Processes

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    In this paper we consider a discrete scale invariant (DSI) process {X(t),tR+}\{X(t), t\in {\bf R^+}\} with scale l>1l>1. We consider to have some fix number of observations in every scale, say TT, and to get our samples at discrete points αk,kW\alpha^k, k\in {\bf W} where α\alpha is obtained by the equality l=αTl=\alpha^T and W={0,1,...}{\bf W}=\{0, 1,...\}. So we provide a discrete time scale invariant (DT-SI) process X()X(\cdot) with parameter space {αk,kW}\{\alpha^k, k\in {\bf W}\}. We find the spectral representation of the covariance function of such DT-SI process. By providing harmonic like representation of multi-dimensional self-similar processes, spectral density function of them are presented. We assume that the process {X(t),tR+}\{X(t), t\in {\bf R^+}\} is also Markov in the wide sense and provide a discrete time scale invariant Markov (DT-SIM) process with the above scheme of sampling. We present an example of DT-SIM process, simple Brownian motion, by the above sampling scheme and verify our results. Finally we find the spectral density matrix of such DT-SIM process and show that its associated TT-dimensional self-similar Markov process is fully specified by {RjH(1),RjH(0),j=0,1,...,T1}\{R_{j}^H(1),R_{j}^H(0),j=0, 1,..., T-1\} where RjH(τ)R_j^H(\tau) is the covariance function of jjth and (j+τ)(j+\tau)th observations of the process.Comment: 16 page

    Molecular characterization of familial hypercholesterolemia in Iranian patients

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    Abstract Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipoprotein metabolism caused mainly by mutations in the low-density lipoprotein receptor (LDLR) and apolipoprotein B 100 (APOB) genes. Until now, the molecular basis of FH has been demonstrated in detail in many populations, but there is still very limited Molecular data concerning FH in Iran. The aim of this study was to characterize the LDLR and APOB gene mutations in an Iranian population. A total of 30 non-related Iranian possible FH subjects were studied. Diagnosis of FH was based on the Dutch Lipid Clinic Network diagnostic criteria. All samples were initially tested for three common APOB gene mutations including R3500Q, R3500 W and R3531C using PCR-RFLP assay. Subsequently, promoter and coding region of the LDLR gene was screened by PCRSSCP analysis and positive results were confirmed by DNA sequencing. Four previously reported polymorphisms 1413G [A, 1725C [T, 1773T [C and 2140 ? 5G[A were found in *17% (5/30) of population studied. Moreover, no variation was found in APOB gene. Our data indicated that LDLR and APOB gene mutations have not contribution to possible FH in Iranian population studied here. However, we examined three common APOB mutations and LDLR in only 30 patients, and to determine the role of these genes in developing FH in Iran, more FH samples and populations needed to be investigated for the mutations of the related gene
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