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Sample records for two-level atom embedded

  1. The geometric phase in two-level atomic systems

    International Nuclear Information System (INIS)

    Tian Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Randall Babbitt, Wm.

    2004-01-01

    We report the observation of the geometric phase in a closed two-level atomic system using stimulated photon echoes. The two-level system studied consists of the two-electronic energy levels ( 3 H 4 and 3 H 6 ) of Tm 3+ doped in YAG crystal. When a two-level atom at an arbitrary superposition state is excited by a pair of specially designed laser pulses, the excited state component gains a relative phase with respect to the ground state component. We identified the phase shift to be of pure geometric nature. The dynamic phase associated to the driving Hamiltonian is unchanged. The experiment results of the phase change agree with the theory to the extent of the measurement limit

  2. The Modified Embedded Atom Method

    Energy Technology Data Exchange (ETDEWEB)

    Baskes, M.I.

    1994-08-01

    Recent modifications have been made to generalize the Embedded Atom Method (EAM) to describe bonding in diverse materials. By including angular dependence of the electron density in an empirical way, the Modified Embedded Atom Method (MEAM) has been able to reproduce the basic energetic and structural properties of 45 elements. This method is ideal for examining interfacial behavior of dissimilar materials. This paper explains in detail the derivation of the method, shows how parameters of MEAM are determined directly from experiment or first principles calculations, and examine the quality of the reproduction of the database. Materials with fcc, bcc, hcp, and diamond cubic crystal structure are discussed. A few simple examples of the application of the MEAM to surfaces and interfaces are presented. Calculations of pullout of a SiC fiber in a diamond matrix as a function of applied stress show nonuniform deformation of the fiber.

  3. Localization of a two-level atom via the absorption spectrum

    International Nuclear Information System (INIS)

    Xu, Jun; Hu, Xiang-Ming

    2007-01-01

    We show that it is possible to localize a two-level atom as it passes through a standing-wave field by measuring the probe-field absorption. There is 50% detecting probability of the atom at the nodes of the standing-wave field in the subwavelength domain when the probe field is tuned resonant with the atomic transition

  4. Ultimate temperature for laser cooling of two-level neutral atoms

    International Nuclear Information System (INIS)

    Bagnato, V.S.; Zilio, S.C.

    1989-01-01

    We present a simple pedagogical method to evaluate the minimum attainable temperature for laser cooling of two-level neutral atoms. Results are given as a function of the laser detuning and intensity. We also discuss the use of this approach to predict the minimum temperature of neutral atoms confined in magnetic traps. (author) [pt

  5. Oscillations of Doppler-Raby of two level atom moving in resonator

    International Nuclear Information System (INIS)

    Kozlovskij, A.V.

    2001-01-01

    The interaction of the two-level atom with the quantum mode of the high-quality resonator uniformly moving by the classic trajectory, is considered. The recurrent formula for the probability of the atom transition with the photon radiation is determined through the dressed states method. It is shown, that the ratio between the Doppler shift value of the atom transition and the Raby frequency value of the atom-field system qualitatively effects the dependence of the moving atom transition probability on its position in the resonator, as well as on its value [ru

  6. Teleporting the one-qubit state via two-level atoms with spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Hu Mingliang, E-mail: mingliang0301@xupt.edu.cn, E-mail: mingliang0301@163.com [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710061 (China)

    2011-05-14

    We study quantum teleportation via two two-level atoms coupled collectively to a multimode vacuum field and prepared initially in different atomic states. We concentrated on the influence of the spontaneous emission, collective damping and dipole-dipole interaction of the atoms on fidelity dynamics of quantum teleportation and obtained the region of spatial distance between the two atoms over which the state can be teleported nonclassically. Moreover, we showed through concrete examples that entanglement of the channel state is the prerequisite but not the only essential quantity for predicting the teleportation fidelity.

  7. Polynomial pseudosupersymmetry underlying a two-level atom in an external electromagnetic field

    International Nuclear Information System (INIS)

    Samsonov, B.F.; Shamshutdinova, V.V.; Gitman, D.M.

    2005-01-01

    Chains of transformations introduced previously were studied in order to obtain electric fields with a time-dependent frequency for which the equation of motion of a two-level atom in the presence of these fields can be solved exactly. It is shown that a polynomial pseudosupersymmetry may be associated to such chains

  8. Random model of two-level atoms interacting with electromagnetic field

    International Nuclear Information System (INIS)

    Kireev, A.N.; Meleshko, A.N.

    1983-12-01

    A phase transition has been studied in a random system of two-level atoms interacting with an electromagnetic field. It is shown that superradiation can arise when there is short-range order in a spin-subsystem. The existence of long-range order is irrelevant for this phase transition

  9. Quantum phase transition in a coupled two-level system embedded in anisotropic three-dimensional photonic crystals.

    Science.gov (United States)

    Shen, H Z; Shao, X Q; Wang, G C; Zhao, X L; Yi, X X

    2016-01-01

    The quantum phase transition (QPT) describes a sudden qualitative change of the macroscopic properties mapped from the eigenspectrum of a quantum many-body system. It has been studied intensively in quantum systems with the spin-boson model, but it has barely been explored for systems in coupled spin-boson models. In this paper, we study the QPT with coupled spin-boson models consisting of coupled two-level atoms embedded in three-dimensional anisotropic photonic crystals. The dynamics of the system is derived exactly by means of the Laplace transform method, which has been proven to be equivalent to the dissipationless non-Markovian dynamics. Drawing on methods for analyzing the ground state, we obtain the phase diagrams through two exact critical equations and two QPTs are found: one QPT is that from the phase without one bound state to the phase with one bound state and another is that from one phase with the bound state having one eigenvalue to another phase where the bound state has two eigenvalues. Our analytical results also suggest a way of control to overcome the effect of decoherence by engineering the spectrum of the reservoirs to approach the non-Markovian regime and to form the bound state of the whole system for quantum devices and quantum statistics.

  10. Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-Juan; FANG Mao-Fa

    2004-01-01

    From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.

  11. Nonlinear Jaynes–Cummings model for two interacting two-level atoms

    International Nuclear Information System (INIS)

    Santos-Sánchez, O de los; González-Gutiérrez, C; Récamier, J

    2016-01-01

    In this work we examine a nonlinear version of the Jaynes–Cummings model for two identical two-level atoms allowing for Ising-like and dipole–dipole interplays between them. The model is said to be nonlinear in the sense that it can incorporate both a general intensity-dependent interaction between the atomic system and the cavity field and/or the presence of a nonlinear medium inside the cavity. As an example, we consider a particular type of atom-field coupling based upon the so-called Buck–Sukumar model and a lossless Kerr-like cavity. We describe the possible effects of such features on the evolution of some quantities of current interest, such as atomic excitation, purity, concurrence, the entropy of the field and the evolution of the latter in phase space. (paper)

  12. Protecting quantum coherence of two-level atoms from vacuum fluctuations of electromagnetic field

    International Nuclear Information System (INIS)

    Liu, Xiaobao; Tian, Zehua; Wang, Jieci; Jing, Jiliang

    2016-01-01

    In the framework of open quantum systems, we study the dynamics of a static polarizable two-level atom interacting with a bath of fluctuating vacuum electromagnetic field and explore under which conditions the coherence of the open quantum system is unaffected by the environment. For both a single-qubit and two-qubit systems, we find that the quantum coherence cannot be protected from noise when the atom interacts with a non-boundary electromagnetic field. However, with the presence of a boundary, the dynamical conditions for the insusceptible of quantum coherence are fulfilled only when the atom is close to the boundary and is transversely polarizable. Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction. -- Highlights: •We study the dynamics of a two-level atom interacting with a bath of fluctuating vacuum electromagnetic field. •For both a single and two-qubit systems, the quantum coherence cannot be protected from noise without a boundary. •The insusceptible of the quantum coherence can be fulfilled only when the atom is close to the boundary and is transversely polarizable. •Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction.

  13. Geometric manipulation of the quantum states of two-level atoms

    International Nuclear Information System (INIS)

    Tian, Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Babbitt, Wm. Randall

    2004-01-01

    Manipulation of the quantum states of two-level atoms has been investigated using laser-controlled geometric phase change, which has the potential to build robust quantum logic gates for quantum computing. For a qubit based on two electronic transition levels of an atom, two basic quantum operations that can make any universal single qubit gate have been designed employing resonant laser pulses. An operation equivalent to a phase gate has been demonstrated using Tm 3+ doped in a yttrium aluminum garnet crystal

  14. Adiabatic interpretation of a two-level atom diode, a laser device for unidirectional transmission of ground-state atoms

    International Nuclear Information System (INIS)

    Ruschhaupt, A.; Muga, J. G.

    2006-01-01

    We present a generalized two-level scheme for an 'atom diode', namely, a laser device that lets a two-level ground-state atom pass in one direction, say from left to right, but not in the opposite direction. The laser field is composed of two lateral state-selective mirror regions and a central pumping region. We demonstrate the robustness of the scheme and propose a physical realization. It is shown that the inclusion of a counterintuitive laser field blocking the excited atoms on the left side of the device is essential for a perfect diode effect. The reason for this, the diodic behavior, and the robustness may be understood with an adiabatic approximation. The conditions to break down the approximation, which imply also the diode failure, are analyzed

  15. Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

    International Nuclear Information System (INIS)

    Liu Jia; Chen Ziyu; Bu Shenping; Zhang Guofeng

    2009-01-01

    Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.

  16. Photon echo with a few photons in two-level atoms

    International Nuclear Information System (INIS)

    Bonarota, M; Dajczgewand, J; Louchet-Chauvet, A; Le Gouët, J-L; Chanelière, T

    2014-01-01

    To store and retrieve signals at the single photon level, various photon echo schemes have resorted to complex preparation steps involving ancillary shelving states in multi-level atoms. For the first time, we experimentally demonstrate photon echo operation at such a low signal intensity without any preparation step, which allows us to work with mere two-level atoms. This simplified approach relies on the so-coined ‘revival of silenced echo’ (ROSE) scheme. Low noise conditions are obtained by returning the atoms to the ground state before the echo emission. In the present paper we manage ROSE in photon counting conditions, showing that very strong control fields can be compatible with extremely weak signals, making ROSE consistent with quantum memory requirements. (paper)

  17. Probe transparency in a two-level medium embedded by a squeezed vacuum

    International Nuclear Information System (INIS)

    Swain, S.; Zhou, P.

    1994-08-01

    Effect of the detuning on the probe absorption spectra of a two-level system with and without a classically driven field in a squeezed vacuum is investigated. For a strong squeezing, there is a threshold which determines the positions and widths of the absorption peaks, for the squeezed parameter M. In a large detuning, the spectra exhibit some resemblance to the Fano spectrum. The squeezing-induced transparency occurs at the frequency 2ω L - ω A in the minimum-uncertainty squeezed vacuum. This effect is not phase-sensitive. (author). 15 refs, 8 figs

  18. Entanglement Criteria of Two Two-Level Atoms Interacting with Two Coupled Modes

    Science.gov (United States)

    Baghshahi, Hamid Reza; Tavassoly, Mohammad Kazem; Faghihi, Mohammad Javad

    2015-08-01

    In this paper, we study the interaction between two two-level atoms and two coupled modes of a quantized radiation field in the form of parametric frequency converter injecting within an optical cavity enclosed by a medium with Kerr nonlinearity. It is demonstrated that, by applying the Bogoliubov-Valatin canonical transformation, the introduced model is reduced to a well-known form of the generalized Jaynes-Cummings model. Then, under particular initial conditions for the atoms (in a coherent superposition of its ground and upper states) and the fields (in a standard coherent state) which may be prepared, the time evolution of state vector of the entire system is analytically evaluated. In order to understand the degree of entanglement between subsystems (atom-field and atom-atom), the dynamics of entanglement through different measures, namely, von Neumann reduced entropy, concurrence and negativity is evaluated. In each case, the effects of Kerr nonlinearity and detuning parameter on the above measures are numerically analyzed, in detail. It is illustrated that the amount of entanglement can be tuned by choosing the evolved parameters, appropriately.

  19. Quantum averaging and resonances: two-level atom in a one-mode classical laser field

    Directory of Open Access Journals (Sweden)

    M. Amniat-Talab

    2007-06-01

    Full Text Available   We use a nonperturbative method based on quantum averaging and an adapted from of resonant transformations to treat the resonances of the Hamiltonian of a two-level atom interacting with a one-mode classical field in Floquet formalism. We illustrate this method by extraction of effective Hamiltonians of the system in two regimes of weak and strong coupling. The results obtained in the strong-coupling regime, are valid in the whole range of the coupling constant for the one-photon zero-field resonance.

  20. Induced absorption and stimulated emission in a driven two-level atom

    International Nuclear Information System (INIS)

    Mavroyannis, C.

    1992-01-01

    We have considered the induced processes that occur in a driven two-level atom, where a laser photon is absorbed and emitted by the ground and by the excited states of the atom, respectively. In the low-intensity limit of the laser field, the induced spectra arising when a laser photon is absorbed by the ground state of the atom consist of two peaks describing induced absorption and stimulated-emission processes, respectively, where the former prevails over the latter. Asymmetry of the spectral lines occurs at off-resonance and its extent depends on the detuning of the laser field. The physical. process where a laser photon is emitted by the excited state is the reverse of that arising from the absorption of a laser photon by the ground state of the atom. The former differs from the latter in that the emission of a laser photon by the excited state occurs in the low frequency regime and that the stimulated-emission process prevails over that of the induced absorption. In this case, amplification of ultrashort pulses is likely to occur without the need of population inversion between the optical transitions. The computed spectra are graphically presented and discussed. (author)

  1. Bayesian feedback versus Markovian feedback in a two-level atom

    International Nuclear Information System (INIS)

    Wiseman, H.M.; Mancini, Stefano; Wang Jin

    2002-01-01

    We compare two different approaches to the control of the dynamics of a continuously monitored open quantum system. The first is Markovian feedback, as introduced in quantum optics by Wiseman and Milburn [Phys. Rev. Lett. 70, 548 (1993)]. The second is feedback based on an estimate of the system state, developed recently by Doherty and Jacobs [Phys. Rev. A 60, 2700 (1999)]. Here we choose to call it, for brevity, Bayesian feedback. For systems with nonlinear dynamics, we expect these two methods of feedback control to give markedly different results. The simplest possible nonlinear system is a driven and damped two-level atom, so we choose this as our model system. The monitoring is taken to be homodyne detection of the atomic fluorescence, and the control is by modulating the driving. The aim of the feedback in both cases is to stabilize the internal state of the atom as close as possible to an arbitrarily chosen pure state, in the presence of inefficient detection and other forms of decoherence. Our results (obtained without recourse to stochastic simulations) prove that Bayesian feedback is never inferior, and is usually superior, to Markovian feedback. However, it would be far more difficult to implement than Markovian feedback and it loses its superiority when obvious simplifying approximations are made. It is thus not clear which form of feedback would be better in the face of inevitable experimental imperfections

  2. The Population Inversion and the Entropy of a Moving Two-Level Atom in Interaction with a Quantized Field

    Science.gov (United States)

    Abo-Kahla, D. A. M.; Abdel-Aty, M.; Farouk, A.

    2018-05-01

    An atom with only two energy eigenvalues is described by a two-dimensional state space spanned by the two energy eigenstates is called a two-level atom. We consider the interaction between a two-level atom system with a constant velocity. An analytic solution of the systems which interacts with a quantized field is provided. Furthermore, the significant effect of the temperature on the atomic inversion, the purity and the information entropy are discussed in case of the initial state either an exited state or a maximally mixed state. Additionally, the effect of the half wavelengths number of the field-mode is investigated.

  3. Absorption spectrum of a two-level atom in a bad cavity with injected squeezed vacuum

    Science.gov (United States)

    Zhou, Peng; Swain, S.

    1996-02-01

    We study the absorption spectrum of a coherently driven two-level atom interacting with a resonant cavity mode which is coupled to a broadband squeezed vacuum through its input-output mirror in the bad cavity limit. We study the modification of the two-photon correlation strength of the injected squeezed vacuum inside the cavity, and show that the equations describing probe absorption in the cavity environment are formally identical to these in free space, but with modified parameters describing the squeezed vacuum. The two photon correlations induced by the squeezed vacuum are always weaker than in free space. We pay particular attention to the spectral behaviour at line centre in the region of intermediate trength driving intensities, where anomalous spectral features such as hole-burning and dispersive profiles are displayed. These unusual spectral features are very sensitive to the squeezing phase and the Rabi frequency of the driving field. We also derive the threshold value of the Rabi frequency which gives rise to the transparency of the probe beam at the driving frequency. When the Rabi frequency is less than the threshold value, the probe beam is absorbed, whilst the probe beam is amplified (without population inversion under certain conditions) when the Rabi frequency is larger than this threshold. The anomalous spectral features all take place in the vicinity of the critical point dividing the different dynamical regimes, probe absorption and amplification, of the atomic radiation. The physical origin of the strong amplification without population inversion, and the feasibility of observing it, are discussed.

  4. Crises-induced intermittencies in a coherently driven system of two-level atoms

    International Nuclear Information System (INIS)

    Pando L, C.L.; Perez, G.; Cerdeira, H.A.

    1993-04-01

    We study the coherent dynamics of a thin layer of two-level atoms driven by an external coherent field and a phase conjugated mirror (PCM). Since the variables of the system are defined on the Bloch sphere, the third dimension is provided by the temporal modulation of the Rabi frequencies, which are induced by a PCM which reflects an electric field with a carrier frequency different from the incident one. We show that as the PCM gain coefficient is changed period doubling leading to chaos occurs. We find crises of attractor merging and attractor widening types related to homoclinic and heteroclinic tangencies respectively. For the attractor merging crises we find the critical exponent for the characteristic time of intermittency versus the control parameter which is given by the gain coefficient of the PCM. We show that during the crises of attractor widening type, another crisis due to attractor destruction occurs as the control parameter is changed. The latter is due to the collision of the old attractor with its basin boundary when a new attractor is created. This new attractor is stable only in a very small interval in the neighborhood of this second crisis. (author). 31 refs, 15 figs

  5. Entropy squeezing for a two-level atom in the Jaynes-Cummings model with an intensity-depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  6. On the deviation from the sech2 superradiant emission law in a two-level atomic system

    International Nuclear Information System (INIS)

    Goncalves, A.E.

    1990-01-01

    The atomic superradiant emission is treated in the single particle mean field approximation. A single particle Hamiltonian, which represents a dressed two-level atom in a radiation field, can be obtained and it is verified that it describes the transient regime of the emission process. While the line shape emission for a bare atom follows the sech 2 law, for the dressed atom the line shape deviates appreciably from this law and it is verified that the deviation depends crucially on the ratio of the dynamic frequency shift to the transition frequency. This kind of deviation is observed in experimental results. (Author) [pt

  7. Coherent effects on two-photon correlation and directional emission of two two-level atoms

    International Nuclear Information System (INIS)

    Ooi, C. H. Raymond; Kim, Byung-Gyu; Lee, Hai-Woong

    2007-01-01

    Sub- and superradiant dynamics of spontaneously decaying atoms are manifestations of collective many-body systems. We study the internal dynamics and the radiation properties of two atoms in free space. Interesting results are obtained when the atoms are separated by less than half a wavelength of the atomic transition, where the dipole-dipole interaction gives rise to new coherent effects, such as (a) coherence between two intermediate collective states, (b) oscillations in the two-photon correlation G (2) , (c) emission of two photons by one atom, and (d) the loss of directional correlation. We compare the population dynamics during the two-photon emission process with the dynamics of single-photon emission in the cases of a Λ and a V scheme. We compute the temporal correlation and angular correlation of two successively emitted photons using the G (2) for different values of atomic separation. We find antibunching when the atomic separation is a quarter wavelength λ/4. Oscillations in the temporal correlation provide a useful feature for measuring subwavelength atomic separation. Strong directional correlation between two emitted photons is found for atomic separation larger than a wavelength. We also compare the directionality of a photon spontaneously emitted by the two atoms prepared in phased-symmetric and phased-antisymmetric entangled states vertical bar ±> k 0 =e ik 0 ·r 1 vertical bar a 1 ,b 2 >±e ik 0 ·r 2 vertical bar b 1 ,a 2 > by a laser pulse with wave vector k 0 . Photon emission is directionally suppressed along k 0 for the phased-antisymmetric state. The directionality ceases for interatomic distances less than λ/2

  8. Open quantum systems and the two-level atom interacting with a single mode of the electromagnetic field

    International Nuclear Information System (INIS)

    Sandulescu, A.; Stefanescu, E.

    1987-07-01

    On the basis of Lindblad theory of open quantum systems we obtain new optical equations for the system of two-level atom interacting with a single mode of the electromagnetic field. The conventional Block equations in a generalized form with field phases are obtained in the hypothesis that all the terms are slowly varying in the rotating frame.(authors)

  9. Wigner functions for nonclassical states of a collection of two-level atoms

    Science.gov (United States)

    Agarwal, G. S.; Dowling, Jonathan P.; Schleich, Wolfgang P.

    1993-01-01

    The general theory of atomic angular momentum states is used to derive the Wigner distribution function for atomic angular momentum number states, coherent states, and squeezed states. These Wigner functions W(theta,phi) are represented as a pseudo-probability distribution in spherical coordinates theta and phi on the surface of a sphere of radius the square root of j(j +1) where j is the total angular momentum.

  10. Low-frequency-field-induced spontaneous-emission interference in a two-level atom placed in an anisotropic photonic crystal

    International Nuclear Information System (INIS)

    Li Gaoxiang; Evers, Joerg; Keitel, Christoph H

    2005-01-01

    We investigate the spontaneous-emission properties of a two-level atom embedded in a three-dimensional anisotropic photonic crystal. In addition to the modified density of states, the atom is driven by a coherent intense low-frequency field (LFF), which creates additional multiphoton decay channels with the exchange of two low-frequency photons and one spontaneous photon during an atomic transition. Due to the low frequency of the applied field, the various transition pathways may interfere with each other and thus give rise to a modified system dynamics. We find that even if all the atomic (bare and induced) transition frequencies are in the conducting band of the photonic crystal, there still may exist a photon-atom bound state in coexistence with propagating modes. The system also allows us to generate narrow lines in the spontaneous-emission spectrum. This spectrum is a function of the distance of the observer from the atom due to the band gap in the photonic crystal. The system properties depend on three characteristic frequencies, which are influenced by quantum interference effects. Thus these results can be attributed to a combination of interference and band-gap effects

  11. Dynamics of a trapped two-level and three-level atom interacting with classical electromagnetic field

    International Nuclear Information System (INIS)

    Ray, Aditi

    2004-01-01

    The dynamics of a two-level atom driven by a single laser beam and three-level atom (Lambda configuration) irradiated by two laser beams are studied taking into account of the quantized center-of-mass motion of the atom. It is shown that the trapped atom system under appropriate resonance condition exhibits the large time-scale revivals when the index of the vibrational sideband responsible for the atomic electronic transition is greater than unity. The revival times are shown to be dependent on the initial number of vibrational excitations and the magnitude of the Lamb-Dicke parameter. The sub-Poissonian statistics in vibrational quantum number is observed at certain time intervals. The minimum time of interaction for which the squeezed states of motional quadrature are generated is found to be decreasing with the increase in the Lamb-Dicke parameter

  12. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian; Shao Bin; Zou Jian

    2009-01-01

    In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.

  13. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    International Nuclear Information System (INIS)

    Jian, Zhang; Bin, Shao; Jian, Zou

    2009-01-01

    In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)

  14. Entanglement manipulation via Coulomb interaction in an optomechanical cavity assisted by two-level cold atoms

    Science.gov (United States)

    Wang, Jing; Tian, Xue-Dong; Liu, Yi-Mou; Cui, Cui-Li; Wu, Jin-Hui

    2018-06-01

    We investigate the stationary entanglement properties in a hybrid system consisting of an optical cavity, a mechanical resonator, a charged object, and an atomic ensemble. Numerical results show that this hybrid system exhibits three kinds of controllable bipartite entanglements in an experimentally accessible parameter regime with the help of the charged object. More importantly, it is viable to enhance on demand each bipartite entanglement at the expense of reducing others by modulating the Coulomb coupling strength. Last but not least, these bipartite entanglements seem more robust against on the environmental temperature for the positive Coulomb interaction.

  15. Coherent control of the group velocity in a dielectric slab doped with duplicated two-level atoms

    Science.gov (United States)

    Ziauddin; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

    2016-01-01

    Coherent control of reflected and transmitted pulses is investigated theoretically through a slab doped with atoms in a duplicated two-level configuration. When a strong control field and a relatively weak probe field are employed, coherent control of the group velocity is achieved via changing the phase shift ϕ between control and probe fields. Furthermore, the peak values in the delay time of the reflected and transmitted pulses are also studied by varying the phase shift ϕ.

  16. Quantum correlations between each two-level system in a pair of atoms and general coherent fields

    Directory of Open Access Journals (Sweden)

    S. Abdel-Khalek

    Full Text Available The quantitative description of the quantum correlations between each two-level system in a two-atom system and the coherent fields initially defined in a coherent state in the framework of power-law potentials (PLPCSs is considered. Specifically, we consider two atoms locally interacting with PLPCSs and take into account the different terms of interactions, the entanglement and quantum discord are studied including the time-dependent coupling and photon transition effects. Using the monogamic relation between the entanglement of formation and quantum discord in tripartite systems, we show that the control and preservation of the different kinds of quantum correlations greatly benefit from the combination of the choice of the physical quantities. Finally, we explore the link between the dynamical behavior of quantum correlations and nonclassicality of the fields with and without atomic motion effect. Keywords: Quantum correlations, Monogamic relation, Coherent states, Power-law potentials, Wehrl entropy

  17. Optomechanically induced transparency in multi-cavity optomechanical system with and without one two-level atom.

    Science.gov (United States)

    Sohail, Amjad; Zhang, Yang; Zhang, Jun; Yu, Chang-Shui

    2016-06-28

    We analytically study the optomechanically induced transparency (OMIT) in the N-cavity system with the Nth cavity driven by pump, probing laser fields and the 1st cavity coupled to mechanical oscillator. We also consider that one atom could be trapped in the ith cavity. Instead of only illustrating the OMIT in such a system, we are interested in how the number of OMIT windows is influenced by the cavities and the atom and what roles the atom could play in different cavities. In the resolved sideband regime, we find that, the number of cavities precisely determines the maximal number of OMIT windows. It is interesting that, when the two-level atom is trapped in the even-labeled cavity, the central absorptive peak (odd N) or dip (even N) is split and forms an extra OMIT window, but if the atom is trapped in the odd-labeled cavity, the central absorptive peak (odd N) or dip (even N) is only broadened and thus changes the width of the OMIT windows rather than induces an extra window.

  18. Temporal Bell-type inequalities for two-level Rydberg atoms coupled to a high-Q resonator

    International Nuclear Information System (INIS)

    Huelga, S.F.; Marshall, T.W.; Santos, E.

    1996-01-01

    Following the strategy of showing specific quantum effects by means of the violation of a classical inequality, a pair of Bell-type inequalities is derived on the basis of certain additional assumptions, whose plausibility is discussed in detail. Such inequalities are violated by the quantum mechanical predictions for the interaction of a two-level Rydberg atom with a single mode sustained by a high-Q resonator. The experimental conditions required in order to show the existence of forbidden values, according to a hidden variables formalism, in a real experiment are analyzed for various initial field statistics. In particular, the revival dynamics expected for the interaction with a coherent field leads to classically forbidden values, which would indicate a purely quantum effect. copyright 1996 The American Physical Society

  19. Atomic dynamics of tin nanoparticles embedded into porous glass

    Energy Technology Data Exchange (ETDEWEB)

    Parshin, P. P.; Zemlyanov, M. G., E-mail: zeml@isssph.kiae.ru; Panova, G. Kh.; Shikov, A. A. [Russian Research Centre Kurchatov Institute (Russian Federation); Kumzerov, Yu. A.; Naberezhnov, A. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Sergueev, I.; Crichton, W. [European Synchrotron Radiation Facility (France); Chumakov, A. I. [Russian Research Centre Kurchatov Institute (Russian Federation); Rueffer, R. [European Synchrotron Radiation Facility (France)

    2012-03-15

    The method of resonant nuclear inelastic absorption of synchrotron radiation has been used to study the phonon spectrum for tin nanoparticles (with a natural isotope mixture) embedded into a porous glassy (silica) matrix with an average pore diameter of 7 nm in comparison to the analogous spectrum of bulk tin enriched with {sup 119}Sn isotope. Differences between the spectra have been observed, which are related to both the dimensional effects and specific structural features of the porous glass-tin nanocomposite. Peculiarities in the dynamics of tin atoms embedded into nanopores of glass are interpreted in terms of a qualitative model of the nanocomposite structure.

  20. Atomic dynamics of tin nanoparticles embedded into porous glass

    International Nuclear Information System (INIS)

    Parshin, P. P.; Zemlyanov, M. G.; Panova, G. Kh.; Shikov, A. A.; Kumzerov, Yu. A.; Naberezhnov, A. A.; Sergueev, I.; Crichton, W.; Chumakov, A. I.; Rüffer, R.

    2012-01-01

    The method of resonant nuclear inelastic absorption of synchrotron radiation has been used to study the phonon spectrum for tin nanoparticles (with a natural isotope mixture) embedded into a porous glassy (silica) matrix with an average pore diameter of 7 nm in comparison to the analogous spectrum of bulk tin enriched with 119 Sn isotope. Differences between the spectra have been observed, which are related to both the dimensional effects and specific structural features of the porous glass-tin nanocomposite. Peculiarities in the dynamics of tin atoms embedded into nanopores of glass are interpreted in terms of a qualitative model of the nanocomposite structure.

  1. Wireless embedded control system for atomically precise manufacturing

    KAUST Repository

    Khan, Yasser; Randall, John N.

    2011-01-01

    This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

  2. Wireless embedded control system for atomically precise manufacturing

    KAUST Repository

    Khan, Yasser

    2011-04-01

    This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

  3. Computer simulation of liquid cesium using embedded atom model

    International Nuclear Information System (INIS)

    Belashchenko, D K; Nikitin, N Yu

    2008-01-01

    The new method is presented for the inventing an embedded atom potential (EAM potential) for liquid metals. This method uses directly the pair correlation function (PCF) of the liquid metal near the melting temperature. Because of the specific analytic form of this EAM potential, the pair term of potential can be calculated using the pair correlation function and, for example, Schommers algorithm. Other parameters of EAM potential may be found using the potential energy, module of compression and pressure at some conditions, mainly near the melting temperature, at very high temperature or in strongly compressed state. We used the simple exponential formula for effective EAM electronic density and a polynomial series for embedding energy. Molecular dynamics method was applied with L. Verlet algorithm. A series of models with 1968 atoms in the basic cube was constructed in temperature interval 323-1923 K. The thermodynamic properties of liquid cesium, structure data and self-diffusion coefficients are calculated. In general, agreement between the model data and known experimental ones is reasonable. The evaluation is given for the critical temperature of cesium models with EAM potential

  4. Quantum metrology of phase for accelerated two-level atom coupled with electromagnetic field with and without boundary

    Science.gov (United States)

    Yang, Ying; Liu, Xiaobao; Wang, Jieci; Jing, Jiliang

    2018-03-01

    We study how to improve the precision of the quantum estimation of phase for an uniformly accelerated atom in fluctuating electromagnetic field by reflecting boundaries. We find that the precision decreases with increases of the acceleration without the boundary. With the presence of a reflecting boundary, the precision depends on the atomic polarization, position and acceleration, which can be effectively enhanced compared to the case without boundary if we choose the appropriate conditions. In particular, with the presence of two parallel reflecting boundaries, we obtain the optimal precision for atomic parallel polarization and the special distance between two boundaries, as if the atom were shielded from the fluctuation.

  5. Relativistic effects in hydrogenlike atoms embedded in Debye plasmas

    International Nuclear Information System (INIS)

    Bielinska-Waz, D.; Karwowski, J.; Saha, B.; Mukherjee, P.K.

    2004-01-01

    Spectra of hydrogenlike atoms embedded in a Debye plasma are investigated. The state energies and the transition rates are studied using a fully relativistic formalism based on the Dirac equation. The effect of the plasma is described by introducing an exponential screening to the nuclear Coulomb potential (the Debye screening). Systematic trends with respect to both the nuclear charge and the screening parameter are observed for all calculated quantities. The pattern of splittings of ns 1/2 , np 1/2 and np 3/2 is modified in a specific way due to the combined relativity and plasma effect. The transition rates decrease with an increase of the Debye parameter as well as with an increase of Z

  6. Generation and amplification of a high-order sideband induced by two-level atoms in a hybrid optomechanical system

    Science.gov (United States)

    Liu, Zeng-Xing; Xiong, Hao; Wu, Ying

    2018-01-01

    It is quite important to enhance and control the optomechanically induced high-order sideband generation to achieve low-power optical comb and high-sensitivity sensing with an integrable structure. Here we present and analyze a proposal for enhancement and manipulation of optical nonlinearity and high-order sideband generation in a hybrid atom-cavity optomechanical system that is coherently driven by a bichromatic input field consisting of a control field and a probe field and that works beyond the perturbative regime. Our numerical analysis with experimentally achievable parameters confirms that robust high-order sideband generation and typical spectral structures with nonperturbative features can be created even under weak driven fields. The dependence of the high-order sideband generation on the atomic parameters are also discussed in detail, including the decay rate of the atoms and the coupling parameter between the atoms and the cavity field. We show that the cutoff order as well as the amplitude of the higher-order sidebands can be well tuned by the atomic coupling strength and the atomic decay rate. The proposed mechanism of enhancing optical nonlinearity is quite general and can be adopted to optomechanical systems with different types of cavity.

  7. Stability of various entanglements in the interaction between two two-level atoms with a quantized field under the influences of several decay sources

    Science.gov (United States)

    Valizadeh, Sh.; Tavassoly, M. K.; Yazdanpanah, N.

    2018-02-01

    In this paper the interaction between two two-level atoms with a single-mode quantized field is studied. To achieve exact information about the physical properties of the system, one should take into account various sources of dissipation such as photon leakage of cavity, spontaneous emission rate of atoms, internal thermal radiation of cavity and dipole-dipole interaction between the two atoms. In order to achieve the desired goals, we obtain the time evolution of the associated density operator by solving the time-dependent Lindblad equation corresponding to the system. Then, we evaluate the temporal behavior of total population inversion and quantum entanglement between the evolved subsystems, numerically. We clearly show that how the damping parameters affect on the dynamics of considered properties. By analyzing the numerical results, we observe that increasing each of the damping sources leads to faster decay of total population inversion. Also, it is observed that, after starting the interaction, the entanglement between one atom with other parts of the system as well as the entanglement between "atom-atom" subsystem and the "field", tend to some constant values very soon. Moreover, the stable values of entanglement are reduced via increasing the damping factor Γ A (ΓA^{(1)} = ΓA^{(2)} = ΓA ) where ΓA is the spontaneous emission rate of each atom. In addition, we find that by increasing the thermal photons, the entropies (entanglements) tend sooner to some increased stable values. Accordingly, we study the atom-atom entanglement by evaluating the concurrence under the influence of dissipation sources, too. At last, the effects of dissipation sources on the genuine tripartite entanglement between the three subsystems include of two two-level atoms and a quantized field are numerically studied. Due to the important role of stationary entanglement in quantum information processing, our results may provide useful hints for practical protocols which require

  8. Effects of an applied low frequency field on the dynamics of a two-level atom interacting with a single-mode field

    International Nuclear Information System (INIS)

    Xun-Wei, Xu; Nian-Hua, Liu

    2010-01-01

    The effects of an applied low frequency field on the dynamics of a two-level atom interacting with a single-mode field are investigated. It is shown that the time evolution of the atomic population is mainly controlled by the coupling constants and the frequency of the low frequency field, which leads to a low frequency modulation function for the time evolution of the upper state population. The amplitude of the modulation function becomes larger as the coupling constants increase. The frequency of the modulation function is proportional to the frequency of the low frequency field, and decreases with increasing coupling constant. (classical areas of phenomenology)

  9. Quantum gate for Q switching in monolithic photonic-band-gap cavities containing two-level atoms

    International Nuclear Information System (INIS)

    Greentree, Andrew D.; Prawer, Steven; Hollenberg, Lloyd C. L.; Salzman, J.

    2006-01-01

    Photonic-band-gap cavities are prime solid-state systems to investigate light-matter interactions in the strong coupling regime. However, as the cavity is defined by the geometry of the periodic dielectric pattern, cavity control in a monolithic structure can be problematic. Thus, either the state coherence is limited by the read-out channel, or in a high-Q cavity, it is nearly decoupled from the external world, making measurement of the state extremely challenging. We present here a method for ameliorating these difficulties by using a coupled cavity arrangement, where one cavity acts as a switch for the other cavity, tuned by control of the atomic transition

  10. Entanglement Dynamics of Linear and Nonlinear Interaction of Two Two-Level Atoms with a Quantized Phase-Damped Field in the Dispersive Regime

    Science.gov (United States)

    Tavassoly, M. K.; Daneshmand, R.; Rustaee, N.

    2018-06-01

    In this paper we study the linear and nonlinear (intensity-dependent) interactions of two two-level atoms with a single-mode quantized field far from resonance, while the phase-damping effect is also taken into account. To find the analytical solution of the atom-field state vector corresponding to the considered model, after deducing the effective Hamiltonian we evaluate the time-dependent elements of the density operator using the master equation approach and superoperator method. Consequently, we are able to study the influences of the special nonlinearity function f (n) = √ {n}, the intensity of the initial coherent state field and the phase-damping parameter on the degree of entanglement of the whole system as well as the field and atom. It is shown that in the presence of damping, by passing time, the amount of entanglement of each subsystem with the rest of system, asymptotically reaches to its stationary and maximum value. Also, the nonlinear interaction does not have any effect on the entanglement of one of the atoms with the rest of system, but it changes the amplitude and time period of entanglement oscillations of the field and the other atom. Moreover, this may cause that, the degree of entanglement which may be low (high) at some moments of time becomes high (low) by entering the intensity-dependent function in the atom-field coupling.

  11. Potential of Transition Metal Atoms Embedded in Buckled Monolayer g-C3N4 as Single-Atom Catalysts

    KAUST Repository

    Li, Shu-Long

    2017-10-27

    We use first-principles calculations to systematically explore the potential of transition metal atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) embedded in buckled monolayer g-C3N4 as single-atom catalysts. We show that clustering of Sc and Ti on g-C3N4 is thermodynamically impeded and that V, Cr, Mn, and Cu are much less susceptible to clustering than the other TM atoms under investigation. Strong bonding of the transition metal atoms in the cavities of g-C3N4 and high diffusion barriers together are responsible for single-atom fixation. Analysis of the CO oxidation process indicates that embedding of Cr and Mn in g-C3N4 gives rise to promising single-atom catalysts at low temperature.

  12. Potential of Transition Metal Atoms Embedded in Buckled Monolayer g-C3N4 as Single-Atom Catalysts

    KAUST Repository

    Li, Shu-Long; Kan, Xiang; Yin, Hui; Gan, Li-Yong; Schwingenschlö gl, Udo; Zhao, Yong

    2017-01-01

    We use first-principles calculations to systematically explore the potential of transition metal atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) embedded in buckled monolayer g-C3N4 as single-atom catalysts. We show that clustering of Sc and Ti on g-C3N4 is thermodynamically impeded and that V, Cr, Mn, and Cu are much less susceptible to clustering than the other TM atoms under investigation. Strong bonding of the transition metal atoms in the cavities of g-C3N4 and high diffusion barriers together are responsible for single-atom fixation. Analysis of the CO oxidation process indicates that embedding of Cr and Mn in g-C3N4 gives rise to promising single-atom catalysts at low temperature.

  13. Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

    International Nuclear Information System (INIS)

    Tavassoly, M.K.; Hekmatara, H.

    2015-01-01

    In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system. (paper)

  14. The calculation of surface free energy based on embedded atom method for solid nickel

    International Nuclear Information System (INIS)

    Luo Wenhua; Hu Wangyu; Su Kalin; Liu Fusheng

    2013-01-01

    Highlights: ► A new solution for accurate prediction of surface free energy based on embedded atom method was proposed. ► The temperature dependent anisotropic surface energy of solid nickel was obtained. ► In isotropic environment, the approach does not change most predictions of bulk material properties. - Abstract: Accurate prediction of surface free energy of crystalline metals is a challenging task. The theory calculations based on embedded atom method potentials often underestimate surface free energy of metals. With an analytical charge density correction to the argument of the embedding energy of embedded atom method, an approach to improve the prediction for surface free energy is presented. This approach is applied to calculate the temperature dependent anisotropic surface energy of bulk nickel and surface energies of nickel nanoparticles, and the obtained results are in good agreement with available experimental data.

  15. Structure stability and magnetism in graphene impurity complexes with embedded V and Nb atoms

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Jyoti [Department of Physics, University College, Kurukshetra University, Kurukshetra 136119, Haryana (India); Kashyap, Manish K., E-mail: manishdft@gmail.com [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Ames Laboratory, U.S. Department of Energy, Iowa State University, Ames, IA 50011-3020 (United States); Taya, Ankur; Rani, Priti [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Saini, Hardev S. [Department of Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana (India); Reshak, A.H. [New Technologies – Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia)

    2017-07-01

    Highlights: • V/Nb embedding in graphene containing monovacancies/divacancies is presented. • Spin polarization near/equal to 100% ensures use of studied nanosystems in spin filter devices. • Bandstructures are analyzed to identify shifting of Dirac cone of graphene. - Abstract: The appearance of vacancy defects could produce appropriate magnetic moment in graphene and the sensitivity to absorb atoms/molecules also increases with this. In this direction, a DFT study of embedding V and Nb atom in graphene containing monovacancies (MV) and divacancies (DV) is reported. Complete/almost complete spin polarization is detected for V/Nb embedding. The origin of magnetism has been identified via interaction of 3d-states of embedded atom with C-p states present in the vicinity of embedded site. The band structures have been analyzed to counter the observed semiconducting nature of graphene in minority spin on embedding V/Nb atom. The isosurface analysis also confirms the induced magnetism of present nanosystems. The present results reveal that these nanosystems have the potential for futuristic applications like spintronics and energy resources.

  16. Quantum Statistical Properties of the Codirectional Kerr Nonlinear Coupler in Terms of su (2 ) Lie Group in Interaction with a Two-level Atom

    Science.gov (United States)

    Abdalla, M. Sebawe; Khalil, E. M.; Obada, A. S.-F.

    2017-08-01

    The problem of the codirectional Kerr coupler has been considered several times from different point of view. In the present paper we introduce the interaction between a two-level atom and the codirectional Kerr nonlinear coupler in terms of su (2 ) Lie algebra. Under certain conditions we have adjusted the Kerr coupler and consequently we have managed to handle the problem. The wave function is obtained by using the evolution operator where the Heisnberg equation of motion is invoked to get the constants of the motion. We note that the Kerr parameter χ as well as the quantum number j plays the role of controlling the atomic inversion behavior. Also the maximum entanglement occurs after a short period of time when χ = 0. On the other hand for the entropy and the variance squeezing we observe that there is exchange between the quadrature variances. Furthermore, the variation in the quantum number j as well as in the parameter χ leads to increase or decrease in the number of fluctuations. Finally we examined the second order correlation function where classical and nonclassical phenomena are observed.

  17. Accelerating NLTE radiative transfer by means of the Forth-and-Back Implicit Lambda Iteration: A two-level atom line formation in 2D Cartesian coordinates

    Science.gov (United States)

    Milić, Ivan; Atanacković, Olga

    2014-10-01

    State-of-the-art methods in multidimensional NLTE radiative transfer are based on the use of local approximate lambda operator within either Jacobi or Gauss-Seidel iterative schemes. Here we propose another approach to the solution of 2D NLTE RT problems, Forth-and-Back Implicit Lambda Iteration (FBILI), developed earlier for 1D geometry. In order to present the method and examine its convergence properties we use the well-known instance of the two-level atom line formation with complete frequency redistribution. In the formal solution of the RT equation we employ short characteristics with two-point algorithm. Using an implicit representation of the source function in the computation of the specific intensities, we compute and store the coefficients of the linear relations J=a+bS between the mean intensity J and the corresponding source function S. The use of iteration factors in the ‘local’ coefficients of these implicit relations in two ‘inward’ sweeps of 2D grid, along with the update of the source function in other two ‘outward’ sweeps leads to four times faster solution than the Jacobi’s one. Moreover, the update made in all four consecutive sweeps of the grid leads to an acceleration by a factor of 6-7 compared to the Jacobi iterative scheme.

  18. Embedded atom approach for gold–silicon system from ab initio

    Indian Academy of Sciences (India)

    In the present paper, an empirical embedded atom method (EAM) potential for gold–silicon (Au–Si) is developed by fitting to ab initio force (the 'force matching' method) and experimental data. The force database is generated within ab initio molecular dynamics (AIMD). The database includes liquid phase at various ...

  19. One- and two-photon ionization of hydrogen atom embedded in Debye plasmas

    International Nuclear Information System (INIS)

    Chang, T. N.; Fang, T. K.; Ho, Y. K.

    2013-01-01

    We present a detailed analysis of the plasma-induced resonance-like atomic structures near the ionization threshold in one- and two-photon ionization of hydrogen atom. Such resonance-like structures result from the migration of the upper bound excited states of bound-bound atomic transitions into the continuum due to the less attractive screened Coulomb potential which simulates the external environmental effect for an atom embedded in Debye plasma. The change from the resonance-like narrow structures into broad continuous spectra as the plasma effect increases could be accounted for by the overlap between the respective wavefunctions of the atomic electron in the initial state and its corresponding outgoing ionized state in the continuum

  20. Tunable meta-atom using liquid metal embedded in stretchable polymer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peng; Yang, Siming; Wang, Qiugu; Jiang, Huawei; Song, Jiming; Dong, Liang, E-mail: ldong@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Jain, Aditya [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Koschny, Thomas; Soukoulis, Costas M. [Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

    2015-07-07

    Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8–12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over more than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range.

  1. Tunable meta-atom using liquid metal embedded in stretchable polymer

    International Nuclear Information System (INIS)

    Liu, Peng; Yang, Siming; Wang, Qiugu; Jiang, Huawei; Song, Jiming; Dong, Liang; Jain, Aditya; Koschny, Thomas; Soukoulis, Costas M.

    2015-01-01

    Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8–12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over more than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range

  2. In-situ observation of atomic self-organization processes in Xe nanocrystals embedded in Al

    International Nuclear Information System (INIS)

    Mitsuishi, K.; Song, M.; Furuya, K.; Birtcher, R. C.; Allen, C. W.; Donnelly, S. E.

    1998-01-01

    Self-organization processes in Xe nanocrystals embedded in Al are observed with in-situ high-resolution electron microscopy. Under electron irradiation, stacking fault type defects are produced in Xe nanocrystals. The defects recover in a layer by layer manner. Detailed analysis of the video reveals that the displacement of Xe atoms in the stacking fault was rather small for the Xe atoms at boundary between Xe and Al, suggesting the possibility of the stacking fault in Xe precipitate originating inside of precipitate, not at the Al/Xe interface

  3. Geminal embedding scheme for optimal atomic basis set construction in correlated calculations

    Energy Technology Data Exchange (ETDEWEB)

    Sorella, S., E-mail: sorella@sissa.it [International School for Advanced Studies (SISSA), Via Beirut 2-4, 34014 Trieste, Italy and INFM Democritos National Simulation Center, Trieste (Italy); Devaux, N.; Dagrada, M., E-mail: mario.dagrada@impmc.upmc.fr [Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Mazzola, G., E-mail: gmazzola@phys.ethz.ch [Theoretische Physik, ETH Zurich, 8093 Zurich (Switzerland); Casula, M., E-mail: michele.casula@impmc.upmc.fr [CNRS and Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2015-12-28

    We introduce an efficient method to construct optimal and system adaptive basis sets for use in electronic structure and quantum Monte Carlo calculations. The method is based on an embedding scheme in which a reference atom is singled out from its environment, while the entire system (atom and environment) is described by a Slater determinant or its antisymmetrized geminal power (AGP) extension. The embedding procedure described here allows for the systematic and consistent contraction of the primitive basis set into geminal embedded orbitals (GEOs), with a dramatic reduction of the number of variational parameters necessary to represent the many-body wave function, for a chosen target accuracy. Within the variational Monte Carlo method, the Slater or AGP part is determined by a variational minimization of the energy of the whole system in presence of a flexible and accurate Jastrow factor, representing most of the dynamical electronic correlation. The resulting GEO basis set opens the way for a fully controlled optimization of many-body wave functions in electronic structure calculation of bulk materials, namely, containing a large number of electrons and atoms. We present applications on the water molecule, the volume collapse transition in cerium, and the high-pressure liquid hydrogen.

  4. Copper atoms embedded in hexagonal boron nitride as potential catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin

    2014-01-01

    We addressed the electronic structure of Cu atoms embedded in hexagonal boron nitride (h-BN) and their catalytic role in CO oxidation by first-principles-based calculations. We showed that Cu atoms prefer to bind directly with the localized defects on h-BN, which act as strong trapping sites for Cu atoms and inhibit their clustering. The strong binding of Cu atoms at boron vacancy also up-shifts the energy level of Cu-d states to the Fermi level and promotes the formation of peroxide-like intermediate. CO oxidation over Cu atoms embedded in h-BN would proceed through the Langmuir-Hinshelwood mechanism with the formation of a peroxide-like complex by reaction of coadsorbed CO and O2, with the dissociation of which the a CO2 molecule and an adsorbed O atom are formed. Then, the embedded Cu atom is regenerated by the reaction of another gaseous CO with the remnant O atom. The calculated energy barriers for the formation and dissociation of peroxide complex and regeneration of embedded Cu atoms are as low as 0.26, 0.11 and 0.03 eV, respectively, indicating the potential high catalytic performance of Cu atoms embedded in h-BN for low temperature CO oxidation. © the Partner Organisations 2014.

  5. Evolution of the field quantum entropy and entanglement in a system of multimode light field interacting resonantly with a two-level atom through N_j-degenerate N~Σ-photon process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.

  6. First row transition metal atoms embedded in multivacancies in a rippled graphene system

    Science.gov (United States)

    Mombrú, Dominique; Faccio, Ricardo; Mombrú, Alvaro W.

    2018-03-01

    Ab-initio calculations based on density functional theory (DFT) have been performed to study systems where a first row transition metal atom is embedded in a rippled graphene due to the existence of an 8-order multivacancy. In addition to these cases, also the inclusion of a zinc atom, with a 3d10 electron configuration, was also studied. Structural distortions and magnetic response for each system were studied. A correlation was found for the magnitude of the rippling and the distortion in the vacancy. Variation in the trends was found for Cu and Zn cases, which were explained on the basis of the filling of the 3dx2-y2 orbital. All the systems exhibit lower magnetic moment in comparison to the metal-less system. The quenching of the magnetic moment due to the carbon atoms in the vacancy is observed for Sc and Cu.

  7. Effect of atomic initial phase difference on spontaneous emission of an atom embedded in photonic crystal

    International Nuclear Information System (INIS)

    Bing, Zhang; Xiu-Dong, Sun; Xiang-Qian, Jiang

    2010-01-01

    We investigate the effect of initial phase difference between the two excited states of a V-type three-level atom on its steady state behaviour of spontaneous emission. A modified density of modes is introduced to calculate the spontaneous emission spectra in photonic crystal. Spectra in free space are also shown to compare with that in photonic crystal with different relative positions of the excited levels from upper band-edge frequency. It is found that the initial phase difference plays an important role in the quantum interference property between the two decay channels. For a zero initial phase, destructive property is presented in the spectra. With the increase of initial phase difference, quantum interference between the two decay channels from upper levels to ground level turns to be constructive. Furthermore, we give an interpretation for the property of these spectra. (atomic and molecular physics)

  8. Atomic force microscopy and confocal laser scanning microscopy on the cytoskeleton of permeabilised and embedded cells

    International Nuclear Information System (INIS)

    Meller, Karl; Theiss, Carsten

    2006-01-01

    We describe a technical method of cell permeabilisation and embedding to study the organisation and distribution of intracellular proteins with aid of atomic force microscopy and confocal laser scanning microscopy in identical areas. While confocal laser scanning microscopy is useful for the identification of certain proteins subsequent labelling with markers or antibodies, atomic force microscopy allows the observation of macromolecular structures in fixed and living cells. To demonstrate the field of application of this preparatory technique, cells were permeabilised, fixed, and the actin cytoskeleton was stained with phalloidin-rhodamine. Confocal laser scanning microscopy was used to show the organisation of these microfilaments, e.g. geodesic dome structures. Thereafter, cells were embedded in Durcupan water-soluble resin, followed by UV-polymerisation of resin at 4 o C. This procedure allowed intracellular visualisation of the cell nucleus or cytoskeletal elements by atomic force microscopy, for instance to analyse the globular organisation of actin filaments. Therefore, this method offers a great potential to combine both microscopy techniques in order to understand and interpret intracellular protein relations, for example, the biochemical and morphological interaction of the cytoskeleton

  9. Modified embedded-atom method interatomic potential for the Fe-Al system

    International Nuclear Information System (INIS)

    Lee, Eunkoo; Lee, Byeong-Joo

    2010-01-01

    An interatomic potential for the Fe-Al binary system has been developed based on the modified embedded-atom method (MEAM) potential formalism. The potential can describe various fundamental physical properties of Fe-Al binary alloys-structural, elastic and thermodynamic properties, defect formation behavior and interactions between defects-in reasonable agreement with experimental data or higher-level calculations. The applicability of the potential to atomistic investigations of various defect formation behaviors and their effects on the mechanical properties of high aluminum steels as well as Fe-Al binary alloys is demonstrated.

  10. Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

    Science.gov (United States)

    Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

    2016-05-01

    We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

  11. Atomic force microscopy applied to study macromolecular content of embedded biological material

    Energy Technology Data Exchange (ETDEWEB)

    Matsko, Nadejda B. [Electron Microscopy Centre, Institute of Applied Physics, HPM C 15.1, ETH-Hoenggerberg, CH-8093, Zurich (Switzerland)]. E-mail: matsko@iap.phys.ethz.ch

    2007-02-15

    We demonstrate that atomic force microscopy represents a powerful tool for the estimation of structural preservation of biological samples embedded in epoxy resin, in terms of their macromolecular distribution and architecture. The comparison of atomic force microscopy (AFM) and transmission electron microscopy (TEM) images of a biosample (Caenorhabditis elegans) prepared following to different types of freeze-substitution protocols (conventional OsO{sub 4} fixation, epoxy fixation) led to the conclusion that high TEM stainability of the sample results from a low macromolecular density of the cellular matrix. We propose a novel procedure aimed to obtain AFM and TEM images of the same particular organelle, which strongly facilitates AFM image interpretation and reveals new ultrastructural aspects (mainly protein arrangement) of a biosample in addition to TEM data.

  12. Copper atoms embedded in hexagonal boron nitride as potential catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin; Duan, Ting; Sui, Yanhui; Meng, Changgong; Han, Yu

    2014-01-01

    We addressed the electronic structure of Cu atoms embedded in hexagonal boron nitride (h-BN) and their catalytic role in CO oxidation by first-principles-based calculations. We showed that Cu atoms prefer to bind directly with the localized defects

  13. Phonon dispersion on Ag (100) surface: A modified analytic embedded atom method study

    International Nuclear Information System (INIS)

    Zhang Xiao-Jun; Chen Chang-Le

    2016-01-01

    Within the harmonic approximation, the analytic expression of the dynamical matrix is derived based on the modified analytic embedded atom method (MAEAM) and the dynamics theory of surface lattice. The surface phonon dispersions along three major symmetry directions, and XM-bar are calculated for the clean Ag (100) surface by using our derived formulas. We then discuss the polarization and localization of surface modes at points X-bar and M-bar by plotting the squared polarization vectors as a function of the layer index. The phonon frequencies of the surface modes calculated by MAEAM are compared with the available experimental and other theoretical data. It is found that the present results are generally in agreement with the referenced experimental or theoretical results, with a maximum deviation of 10.4%. The agreement shows that the modified analytic embedded atom method is a reasonable many-body potential model to quickly describe the surface lattice vibration. It also lays a significant foundation for studying the surface lattice vibration in other metals. (paper)

  14. Coherent response of a two-level atom to a signal field with account of suppression of phase relaxation by a strong field

    International Nuclear Information System (INIS)

    Grishanin, B.A.; Shatalova, G.G.

    1984-01-01

    Calculation is made of a coherent part of response to a weak test field of an atom located in a strong resonance field. The latter bads to a suppression of phase relaxation. This response is shown to appear both at a test field freq uency ω and at a combination frequency 2ωsub(l)-ω, where ωsub(l) is a resona nce field frequency. The spectrum of test field absorption by such a system has a symmetric form and consist of two parts, one of which corresponds to a test f ield absorption and another - to its amplification

  15. Position Dependent Spontaneous Emission Spectra of a Λ-Type Atomic System Embedded in a Defective Photonic Crystal

    International Nuclear Information System (INIS)

    Entezar, S. Roshan

    2012-01-01

    We investigate the position dependent spontaneous emission spectra of a Λ-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location (or in the absence of the defect mode), the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high (low) dielectric regions far from the defect location, effectively couple to the modes of the lower (upper) photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high (low) dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower (upper) photonic band modes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  16. Indium-defect interactions in FCC and BCC metals studied using the modified embedded atom method

    Energy Technology Data Exchange (ETDEWEB)

    Zacate, M. O., E-mail: zacatem1@nku.edu [Northern Kentucky University, Department of Physics, Geology, and Engineering Technology (United States)

    2016-12-15

    With the aim of developing a transferable potential set capable of predicting defect formation, defect association, and diffusion properties in a wide range of intermetallic compounds, the present study was undertaken to test parameterization strategies for determining empirical pair-wise interaction parameters in the modified embedded atom method (MEAM) developed by Baskes and coworkers. This report focuses on indium-solute and indium-vacancy interactions in FCC and BCC metals, for which a large set of experimental data obtained from perturbed angular correlation measurements is available for comparison. Simulation results were found to be in good agreement with experimental values after model parameters had been adjusted to reproduce as best as possible the following two sets of quantities: (1) lattice parameters, formation enthalpies, and bulk moduli of hypothetical equiatomic compounds with the NaCl crystal structure determined using density functional theory and (2) dilute solution enthalpies in metals as predicted by Miedema’s semi-empirical model.

  17. Study of the embedded atom method of atomistic calculations for metals and alloys

    International Nuclear Information System (INIS)

    Johnson, R.A.

    1990-10-01

    Two projects were completed in the past year. The stability of a series of binary alloys was calculated using the embedded-atom method (EAM) with an analytic form for two-body potentials derived previously. Both disordered alloys and intermetallic compounds with the L1 0 and L1 2 structures were studied. The calculated heats of solution of alloys of Cu, Ag, Au, Ni, and Pt were satisfactory, while results for alloys containing Pd were too high. Atomistic calculations using the EAM were also carried out for point defects in hcp metals. By comparison with results in the literature, it was found that many body effects from the EAM significantly alter predicted physical properties of hcp metals. For example, the EAM calculations yield anisotropic vacancy diffusion with greater vacancy mobility in the basal plane, and imply that diffusion will start at a lower fraction of the melting temperature

  18. Optical resonance and two-level atoms

    CERN Document Server

    Allen, L

    1987-01-01

    ""Coherent and lucid…a valuable summary of a subject to which [the authors] have made significant contributions by their own research."" - Contemporary PhysicsOffering an admirably clear account of the basic principles behind all quantum optical resonance phenomena, and hailed as a valuable contribution to the literature of nonlinear optics, this distinguished work provides graduate students and research physicists probing fields such as laser physics, quantum optics, nonlinear optics, quantum electronics, and resonance optics an ideal introduction to the study of the interaction of electroma

  19. Atomic structure of embedded Fe nanoclusters as a function of host matrix material: a synchrotron radiation study

    International Nuclear Information System (INIS)

    Baker, S H; Roy, M; Gurman, S J; Louch, S; Bleloch, A; Binns, C

    2004-01-01

    The atomic structure of Fe nanoclusters embedded in a range of matrix materials has been studied using synchrotron radiation. In particular, the effect of embedding the clusters in Ag, amorphous carbon (a-C) and a porous C 60 matrix is investigated. The embedded cluster samples were prepared by co-deposition using a gas aggregation cluster source. Samples with both dilute and high-volume-filling fraction of clusters, at 4 and 40% respectively, were prepared. Fe K edge EXAFS measurements were used to probe the structure within the clusters. In a Ag matrix, the Fe clusters retain the b.c.c. structure of bulk Fe while in a-C there is evidence for both b.c.c. and f.c.c. structures in the clusters. These results are independent of cluster volume-filling fraction over the range investigated. When embedded in a porous C 60 matrix, the Fe clusters oxidize to Fe 2 O 3

  20. Molecular dynamics for near melting temperatures simulations of metals using modified embedded-atom method

    Science.gov (United States)

    Etesami, S. Alireza; Asadi, Ebrahim

    2018-01-01

    Availability of a reliable interatomic potential is one of the major challenges in utilizing molecular dynamics (MD) for simulations of metals at near the melting temperatures and melting point (MP). Here, we propose a novel approach to address this challenge in the concept of modified-embedded-atom (MEAM) interatomic potential; also, we apply the approach on iron, nickel, copper, and aluminum as case studies. We propose adding experimentally available high temperature elastic constants and MP of the element to the list of typical low temperature properties used for the development of MD interatomic potential parameters. We show that the proposed approach results in a reasonable agreement between the MD calculations of melting properties such as latent heat, expansion in melting, liquid structure factor, and solid-liquid interface stiffness and their experimental/computational counterparts. Then, we present the physical properties of mentioned elements near melting temperatures using the new MEAM parameters. We observe that the behavior of elastic constants, heat capacity and thermal linear expansion coefficient at room temperature compared to MP follows an empirical linear relation (α±β × MP) for transition metals. Furthermore, a linear relation between the tetragonal shear modulus and the enthalpy change from room temperature to MP is observed for face-centered cubic materials.

  1. Charge-transfer modified embedded atom method dynamic charge potential for Li-Co-O system.

    Science.gov (United States)

    Kong, Fantai; Longo, Roberto C; Liang, Chaoping; Nie, Yifan; Zheng, Yongping; Zhang, Chenxi; Cho, Kyeongjae

    2017-11-29

    To overcome the limitation of conventional fixed charge potential methods for the study of Li-ion battery cathode materials, a dynamic charge potential method, charge-transfer modified embedded atom method (CT-MEAM), has been developed and applied to the Li-Co-O ternary system. The accuracy of the potential has been tested and validated by reproducing a variety of structural and electrochemical properties of LiCoO 2 . A detailed analysis on the local charge distribution confirmed the capability of this potential for dynamic charge modeling. The transferability of the potential is also demonstrated by its reliability in describing Li-rich Li 2 CoO 2 and Li-deficient LiCo 2 O 4 compounds, including their phase stability, equilibrium volume, charge states and cathode voltages. These results demonstrate that the CT-MEAM dynamic charge potential could help to overcome the challenge of modeling complex ternary transition metal oxides. This work can promote molecular dynamics studies of Li ion cathode materials and other important transition metal oxides systems that involve complex electrochemical and catalytic reactions.

  2. Pt Single Atoms Embedded in the Surface of Ni Nanocrystals as Highly Active Catalysts for Selective Hydrogenation of Nitro Compounds.

    Science.gov (United States)

    Peng, Yuhan; Geng, Zhigang; Zhao, Songtao; Wang, Liangbing; Li, Hongliang; Wang, Xu; Zheng, Xusheng; Zhu, Junfa; Li, Zhenyu; Si, Rui; Zeng, Jie

    2018-06-13

    Single-atom catalysts exhibit high selectivity in hydrogenation due to their isolated active sites, which ensure uniform adsorption configurations of substrate molecules. Compared with the achievement in catalytic selectivity, there is still a long way to go in exploiting the catalytic activity of single-atom catalysts. Herein, we developed highly active and selective catalysts in selective hydrogenation by embedding Pt single atoms in the surface of Ni nanocrystals (denoted as Pt 1 /Ni nanocrystals). During the hydrogenation of 3-nitrostyrene, the TOF numbers based on surface Pt atoms of Pt 1 /Ni nanocrystals reached ∼1800 h -1 under 3 atm of H 2 at 40 °C, much higher than that of Pt single atoms supported on active carbon, TiO 2 , SiO 2 , and ZSM-5. Mechanistic studies reveal that the remarkable activity of Pt 1 /Ni nanocrystals derived from sufficient hydrogen supply because of spontaneous dissociation of H 2 on both Pt and Ni atoms as well as facile diffusion of H atoms on Pt 1 /Ni nanocrystals. Moreover, the ensemble composed of the Pt single atom and nearby Ni atoms in Pt 1 /Ni nanocrystals leads to the adsorption configuration of 3-nitrostyrene favorable for the activation of nitro groups, accounting for the high selectivity for 3-vinylaniline.

  3. Effective embedded-atom potential for metallic adsorbates on crystalline surfaces

    International Nuclear Information System (INIS)

    Förster, G D; Magnin, Y; Rabilloud, F; Calvo, F

    2014-01-01

    Based on the embedded-atom method (EAM), an analytical effective potential is developed to model the interaction of a metallic adsorbate on a perfect crystalline substrate, which is also metallic. The many-body character of the original EAM potential is preserved in the adsorbate energy and in the alteration of the substrate energy due to the presence of the adsorbate. A mean-field-type version neglecting corrugation of the substrate is first derived based on rigorous integration of individual monolayers, followed by an approximate form for the perturbation of the substrate energy. Lateral corrugation is subsequently included by additional phenomenological terms respecting the symmetry of the substrate, again preserving the many-body nature of the original potential. The effective model contains four parameters to describe uncorrugated substrates and eight extra parameters to describe every order of the Fourier lateral expansion. These parameters were fitted to reproduce the adsorption energy of a sample of random configurations of realistic 2D and 3D clusters deposited on the (1 1 1) fcc surface, for metals for which popular EAM models have been parametrized. As a simple application, the local relaxation of pre-formed icosahedral or truncated octahedral clusters soft-landed and exposing (1 1 1) faces in epitaxy to the substrate has been simulated at 0 and 300 K. The deformation of small clusters to wet the substrate is correctly captured by the effective model. This agreement with the exact potential suggests that the present model should be useful for treating metallic environments in large-scale surface studies, notably in structural optimization or as a template for more general models parametrized from ab initio data. (paper)

  4. Modification and control of the spontaneous emission from an M-type atom embedded in an anisotropic photonic crystal

    International Nuclear Information System (INIS)

    Ding Chunling; Li Jiahua; Yang Xiaoxue; Lue Xinyou

    2011-01-01

    We describe the spontaneous emission properties of an M-type five-level atom embedded in a photonic crystal (PC), which is coherently driven by two external laser fields. It leads to two types of quantum interference: reservoir-induced interference and laser-induced interference. Considering different detunings of atomic transition frequencies from band edges, we reveal some interesting phenomena such as spectral-line enhancement, spectral-line suppression, spectral-line narrowing, reservoir-induced cancellation of spontaneous emission and the appearance of dark lines, which originate from the quantum interference effects and the control of external laser fields. These investigations suggest possible applications in quantum optics, optical communications and in the fabrication of novel optoelectronic devices.

  5. Atomic structure and thermal stability of interfaces between metallic glass and embedding nano-crystallites revealed by molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Gao, X.Z.; Yang, G.Q.; Xu, B.; Qi, C.; Kong, L.T., E-mail: konglt@sjtu.edu.cn; Li, J.F.

    2015-10-25

    Molecular dynamics simulations were performed to investigate the atomic structure and thermal stability of interfaces formed between amorphous Cu{sub 50}Zr{sub 50} matrix and embedding B2 CuZr nano-crystallites. The interfaces are found to be rather abrupt, and their widths show negligible dependence on the nano-crystallite size. Local atomic configuration in the interfacial region is dominated by geometry characterized by Voronoi polyhedra <0,5,2,6> and <0,4,4,6>, and the contents of these polyhedra also exhibit apparent size dependence, which in turn results in an increasing trend in the interfacial energy against the nano-crystallite size. Annealing of the interface models at elevated temperatures will also enrich these characterizing polyhedra. While when the temperature is as high as the glass transition temperature of the matrix, growth of the nano-crystallites will be appreciable. The growth activation energy also shows size dependence, which is lower for larger nano-crystallites, suggesting that large nano-crystallites are prone to grow upon thermal disturbance. - Highlights: • Special clusters characterizing the local geometry are abundant in the interfaces. • Their content varies with the size of the embedding nano-crystallite. • In turn, size dependences in interfacial thermodynamics and kinetics are observed.

  6. Unique Reactivity of Transition Metal Atoms Embedded in Graphene to CO, NO, O₂ and O Adsorption: A First-Principles Investigation.

    Science.gov (United States)

    Chu, Minmin; Liu, Xin; Sui, Yanhui; Luo, Jie; Meng, Changgong

    2015-10-27

    Taking the adsorption of CO, NO, O₂ and O as probes, we investigated the electronic structure of transition metal atoms (TM, TM = Fe, Co, Ni, Cu and Zn) embedded in graphene by first-principles-based calculations. We showed that these TM atoms can be effectively stabilized on monovacancy defects on graphene by forming plausible interactions with the C atoms associated with dangling bonds. These interactions not only give rise to high energy barriers for the diffusion and aggregation of the embedded TM atoms to withstand the interference of reaction environments, but also shift the energy levels of TM-d states and regulate the reactivity of the embedded TM atoms. The adsorption of CO, NO, O₂ and O correlates well with the weight averaged energy level of TM-d states, showing the crucial role of interfacial TM-C interactions on manipulating the reactivity of embedded TM atoms. These findings pave the way for the developments of effective monodispersed atomic TM composites with high stability and desired performance for gas sensing and catalytic applications.

  7. Two-photon transitions in hydrogen atoms embedded in weakly coupled plasmas

    International Nuclear Information System (INIS)

    Paul, S.; Ho, Y. K.

    2008-01-01

    The pseudostate method has been applied to calculate energy eigenvalues and corresponding eigenfunctions of the hydrogen atom in Debye plasma environments. Resonant two-photon transition rates from the ground state of atomic hydrogen to 2s and 3s excited states have been computed as a function of photon frequency in the length and velocity gauges for different Debye lengths. A two-photon transparency is found in correspondence to each resonance for 1s-3s. The transparency frequency and resonance enhancement frequency vary significantly with the Debye length.

  8. Atom-Photon Coupling from Nitrogen-vacancy Centres Embedded in Tellurite Microspheres

    Science.gov (United States)

    Ruan, Yinlan; Gibson, Brant C.; Lau, Desmond W. M.; Greentree, Andrew D.; Ji, Hong; Ebendorff-Heidepriem, Heike; Johnson, Brett C.; Ohshima, Takeshi; Monro, Tanya M.

    2015-06-01

    We have developed a technique for creating high quality tellurite microspheres with embedded nanodiamonds (NDs) containing nitrogen-vacancy (NV) centres. This hybrid method allows fluorescence of the NVs in the NDs to be directly, rather than evanescently, coupled to the whispering gallery modes of the tellurite microspheres at room temperature. As a demonstration of its sensing potential, shifting of the resonance peaks is also demonstrated by coating a sphere surface with a liquid layer. This new approach is a robust way of creating cavities for use in quantum and sensing applications.

  9. 'No one to trust': the cultural embedding of atomism in financial markets.

    Science.gov (United States)

    Ailon, Galit

    2018-05-13

    The paper ethnographically explores the cultural embedding of atomistic indifference in online, global financial markets: arenas that have been digitally designed according to economic ideals and that demand an extreme form of relational and social dissociation from the partners to exchange and from those affected by the transactions. Its case-study is lay financial-trading in Israel, a country undergoing extensive neoliberalization. The study shows that dissociation is embedded in an economic culture marked by constant, multi-sited declarations that economic-Others are cold, uncaring and manipulative. It takes shape as traders convert the distrust towards Others into distrust towards portions of the Self that represent links to these Others, namely their own social-psychology and social concern. Acting atomistically and selfishly in the market thus entails considerable reflexive work. The paper contributes to an ongoing debate on the moral and cultural embeddedness of markets in general and of the expanding financial markets in particular. © London School of Economics and Political Science 2018.

  10. Numerical Analysis of the Primary Breakup Applying the Embedded DNS Approach to a Generic Prefilming Airblast Atomizer

    Directory of Open Access Journals (Sweden)

    Benjamin Sauer

    2014-09-01

    Full Text Available An improved understanding of the breakup processes of two-phase flows is essential to effectively control the fuel atomization for future aircraft engines. A detailed insight into the phenomena of primary breakup is a major limitation in gaining this knowledge. Aircraft engines use airblast atomizers to provide the fuel atomization. The geometries of airblast atomizers are complex, the operating conditions are characterized by high Reynolds- and Weber numbers. Direct Numerical Simulations (DNS of liquid breakup under realistic conditions and geometries are hardly possible. The embedded DNS (eDNS concept aims to fill this gap. The concept consists of three steps: a geometry simplification, the generation of realistic boundary conditions for the DNS and the DNS of the breakup region. The realistic annular airblast atomizer geometry is simplified to a planar geometry. Inside this domain the eDNS is located. The eDNS domain requires the generation of boundary conditions. A zonal Large Eddy Simulation (LES of the turbulent channel flow is performed prior to the DNS. The parameters are stored transiently on the “virtual” DNS inlet planes. These variables are then mapped to the DNS. The Volume of fluid (VOF method is used to solve for the two-phase flow. DNS are performed for a shear-driven liquid wall film and for a generic planar prefilming airblast atomizer. As the Reynolds and Weber number for the first operating point (OP are low (Reair = 5,333/Wefilm = 1.9, the liquid wall film as well as the liquid sheet show no surface waves. For the second case with Reair = 13,333 and We film = 11.9, the surface appears more wrinkled and streamwise waves are transported along the wall for the shear-driven wall film. Instantaneous snapshots in 2–D and 3–D illustrate the qualitative behavior of the liquid sheet in time. Leaving the prefilmer trailing edge, the liquid sheet starts to oscillate in a sinusoidal fashion. This oscillation appears crucial for

  11. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    Energy Technology Data Exchange (ETDEWEB)

    Mikhelashvili, V.; Padmanabhan, R.; Eisenstein, G. [Electrical Engineering Department, Technion, Haifa 3200 (Israel); Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Meyler, B.; Yofis, S.; Weindling, S.; Salzman, J. [Electrical Engineering Department, Technion, Haifa 3200 (Israel); Atiya, G.; Cohen-Hyams, Z.; Kaplan, W. D. [Department of Material Science and Engineering, Technion, Haifa 3200 (Israel); Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Ankonina, G. [Russell Berrie Nanotechnology Institute, Technion, Haifa 3200 (Israel); Photovoltaic Laboratory, Technion, Haifa 3200 (Israel)

    2015-10-07

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology.

  12. Optically sensitive devices based on Pt nano particles fabricated by atomic layer deposition and embedded in a dielectric stack

    International Nuclear Information System (INIS)

    Mikhelashvili, V.; Padmanabhan, R.; Eisenstein, G.; Meyler, B.; Yofis, S.; Weindling, S.; Salzman, J.; Atiya, G.; Cohen-Hyams, Z.; Kaplan, W. D.; Ankonina, G.

    2015-01-01

    We report a series of metal insulator semiconductor devices with embedded Pt nano particles (NPs) fabricated using a low temperature atomic layer deposition process. Optically sensitive nonvolatile memory cells as well as optical sensors: (i) varactors, whose capacitance-voltage characteristics, nonlinearity, and peak capacitance are strongly dependent on illumination intensity; (ii) highly linear photo detectors whose responsivity is enhanced due to the Pt NPs. Both single devices and back to back pairs of diodes were used. The different configurations enable a variety of functionalities with many potential applications in biomedical sensing, environmental surveying, simple imagers for consumer electronics and military uses. The simplicity and planar configuration of the proposed devices makes them suitable for standard CMOS fabrication technology

  13. Atomic Layer Deposited Oxide-Based Nanocomposite Structures with Embedded CoPtx Nanocrystals for Resistive Random Access Memory Applications.

    Science.gov (United States)

    Wang, Lai-Guo; Cao, Zheng-Yi; Qian, Xu; Zhu, Lin; Cui, Da-Peng; Li, Ai-Dong; Wu, Di

    2017-02-22

    Al 2 O 3 - or HfO 2 -based nanocomposite structures with embedded CoPt x nanocrystals (NCs) on TiN-coated Si substrates have been prepared by combination of thermal atomic layer deposition (ALD) and plasma-enhanced ALD for resistive random access memory (RRAM) applications. The impact of CoPt x NCs and their average size/density on the resistive switching properties has been explored. Compared to the control sample without CoPt x NCs, ALD-derived Pt/oxide/100 cycle-CoPt x NCs/TiN/SiO 2 /Si exhibits a typical bipolar, reliable, and reproducible resistive switching behavior, such as sharp distribution of RRAM parameters, smaller set/reset voltages, stable resistance ratio (≥10 2 ) of OFF/ON states, better switching endurance up to 10 4 cycles, and longer data retention over 10 5 s. The possible resistive switching mechanism based on nanocomposite structures of oxide/CoPt x NCs has been proposed. The dominant conduction mechanisms in low- and high-resistance states of oxide-based device units with embedded CoPt x NCs are Ohmic behavior and space-charge-limited current, respectively. The insertion of CoPt x NCs can effectively improve the formation of conducting filaments due to the CoPt x NC-enhanced electric field intensity. Besides excellent resistive switching performances, the nanocomposite structures also simultaneously present ferromagnetic property. This work provides a flexible pathway by combining PEALD and TALD compatible with state-of-the-art Si-based technology for multifunctional electronic devices applications containing RRAM.

  14. Parametric resonances in the amplitude-modulated probe-field absorption spectrum of a two-level atom driven by a resonance amplitude- and phase-modulated pumping field

    International Nuclear Information System (INIS)

    Sushilov, N.V.; Kholodkevich, E.D.

    1995-01-01

    An analytical expression is derived for the polarization induced by a weak probe field with periodically modulated amplitude in a two-level medium saturated by a strong amplitude-and phase-modulated resonance field. It is shown that the absorption spectrum of the probe field includes parametric resonances, the maxima corresponding to the condition δ= 2nΓ-Ω w and the minima to that of δ= (2n + 1)Γ- w , where δ is the probe-field detuning front the resonance frequency, Ω w is the modulation frequency of the probe-field amplitude, and Γ is the transition line width, n = 1, 2, 3, hor-ellipsis. At the specific modulation parameters, a substantial region of negative values (i.e., the region of amplification without the population inversion) exists in the absorption spectrum of the probe field

  15. Basal and prism dislocation cores in magnesium: comparison of first-principles and embedded-atom-potential methods predictions

    International Nuclear Information System (INIS)

    Yasi, J A; Nogaret, T; Curtin, W A; Trinkle, D R; Qi, Y; Hector, L G Jr

    2009-01-01

    The core structures of screw and edge dislocations on the basal and prism planes in Mg, and the associated gamma surfaces, were studied using an ab initio method and the embedded-atom-method interatomic potentials developed by Sun et al and Liu et al. The ab initio calculations predict that the basal plane dislocations dissociate into partials split by 16.7 Å (edge) and 6.3 Å (screw), as compared with 14.3 Å and 12.7 Å (Sun and Liu edge), and 6.3 Å and 1.4 Å (Sun and Liu screw), with the Liu screw dislocation being metastable. In the prism plane, the screw and edge cores are compact and the edge core structures are all similar, while ab initio does not predict a stable prismatic screw in stress-free conditions. These results are qualitatively understood through an examination of the gamma surfaces for interplanar sliding on the basal and prism planes. The Peierls stresses at T = 0 K for basal slip are a few megapascals for the Sun potential, in agreement with experiments, but are ten times larger for the Liu potential. The Peierls stresses for prism slip are 10–40 MPa for both potentials. Overall, the dislocation core structures from ab initio are well represented by the Sun potential in all cases while the Liu potential shows some notable differences. These results suggest that the Sun potential is preferable for studying other dislocations in Mg, particularly the (c + a) dislocations, for which the core structures are much larger and not accessible by ab initio methods

  16. Transformation mechanism of n-butyl terminated Si nanoparticles embedded into Si1-xCx nanocomposites mixed with Si nanoparticles and C atoms

    International Nuclear Information System (INIS)

    Shin, J.W.; Oh, D.H.; Kim, T.W.; Cho, W.J.

    2009-01-01

    Bright-field transmission electron microscopy (TEM) images, high-resolution TEM (HRTEM) images, and fast-Fourier transformed electron-diffraction patterns showed that n-butyl terminated Si nanoparticles were aggregated. The formation of Si 1-x C x nanocomposites was mixed with Si nanoparticles and C atoms embedded in a SiO 2 layer due to the diffusion of C atoms from n-butyl termination shells into aggregated Si nanoparticles. Atomic force microscopy (AFM) images showed that the Si 1-x C x nanocomposites mixed with Si nanoparticles and C atoms existed in almost all regions of the SiO 2 layer. The formation mechanism of Si nanoparticles and the transformation mechanism of n-butyl terminated Si nanoparticles embedded into Si 1-x C x nanocomposites mixed with Si nanoparticles and C atoms are described on the basis of the TEM, HRTEM, and AFM results. These results can help to improve the understanding of the formation mechanism of Si nanoparticles.

  17. The ternary Ni—Al—Co embedded-atom-method potential for γ/γ' Ni-based single-crystal superalloys: Construction and application

    International Nuclear Information System (INIS)

    Du Jun-Ping; Wang Chong-Yu; Yu Tao

    2014-01-01

    An Ni—Al—Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni 3 Al) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, Al) random solid solutions are calculated as a function of the concentrations of Co and Al. The calculated SFEs decrease with increasing concentrations of Co and Al, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co

  18. Monodisperse embedded nanoparticles derived from an atomic metal-dispersed precursor of layered double hydroxide for architectured carbon nanotube formation

    DEFF Research Database (Denmark)

    Tian, Gui-Li; Zhao, Meng-Qiang; Zhang, Bingsen

    2014-01-01

    . When the areal density was increased from 0.039 to 0.55, and to 2.1 x 10(15) m(-2), the Fe NPs embedded on the LDO flakes exhibited good catalytic performance for the growth of entangled carbon nanotubes (CNTs), aligned CNTs, and double helical CNTs, respectively. This work provides not only new...

  19. Atoms

    International Nuclear Information System (INIS)

    Fuchs, Alain; Villani, Cedric; Guthleben, Denis; Leduc, Michele; Brenner, Anastasios; Pouthas, Joel; Perrin, Jean

    2014-01-01

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  20. Darboux transformation for two-level system

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.; Baldiotti, M.; Gitman, D.; Shamshutdinova, V. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil)

    2005-06-01

    We develop the Darboux procedure for the case of the two-level system. In particular, it is demonstrated that one can construct the Darboux intertwining operator that does not violate the specific structure of the equations of the two-level system, transforming only one real potential into another real potential. We apply the obtained Darboux transformation to known exact solutions of the two-level system. Thus, we find three classes of new solutions for the two-level system and the corresponding new potentials that allow such solutions. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  1. Study of the embedded atom method of atomistic calculations for metals and alloys. Final report, March 1, 1986--February 29, 1992

    International Nuclear Information System (INIS)

    Johnson, R.A.

    1992-04-01

    Solids have been studied by atomistic modeling since the earliest availability of computers for scientific research. By the mid sixties, it was understood that models for metals based on reasonably short ranged two-body forces coupled with a global volume dependent contribution to the crystal energy yielded surprisingly good results for bulk calculations, but were unsatisfactory at surfaces. Little progress was made until the early eighties, when Daw and Baskes developed the Embedded-Atom Method (EAM) based on density functional theory and intended primarily for tight-packed transitional metals, and Finnis and Sinclair developed a model based on tight binding theory and intended primarily for bcc transition metals. The underlying mathematical format of both approaches is the same, and provides an extension of the earlier models through a function which in practice provides a measure of local volume dependence. The primary purpose of this research project was to investigate the implications of this mathematical format and to use the resulting insight to correlate the known physical input data with computed results of properties that are difficult to access experimentally. Embedded-Atom Method terminology is used, but this research is applicable as well to the Finnis-Sinclair model

  2. Atom

    International Nuclear Information System (INIS)

    Auffray, J.P.

    1997-01-01

    The atom through centuries, has been imagined, described, explored, then accelerated, combined...But what happens truly inside the atom? And what are mechanisms who allow its stability? Physicist and historian of sciences, Jean-Paul Auffray explains that these questions are to the heart of the modern physics and it brings them a new lighting. (N.C.)

  3. Controlling magnetism of MoS2 sheets by embedding transition-metal atoms and applying strain.

    Science.gov (United States)

    Zhou, Yungang; Su, Qiulei; Wang, Zhiguo; Deng, Huiqiu; Zu, Xiaotao

    2013-11-14

    Prompted by recent experimental achievement of transition metal (TM) atoms substituted in MoS2 nanostructures during growth or saturating existing vacancies (Sun et al., ACS Nano, 2013, 7, 3506; Deepak et al., J. Am. Chem. Soc., 2007, 129, 12549), we explored, via density functional theory, the magnetic properties of a series of 3d TM atoms substituted in a MoS2 sheet, and found that Mn, Fe, Co, Ni, Cu and Zn substitutions can induce magnetism in the MoS2 sheet. The localizing unpaired 3d electrons of TM atoms respond to the introduction of a magnetic moment. Depending on the species of TM atoms, the substituted MoS2 sheet can be a metal, semiconductor or half-metal. Remarkably, the applied elastic strain can be used to control the strength of the spin-splitting of TM-3d orbitals, leading to an effective manipulation of the magnetism of the TM-substituted MoS2 sheet. We found that the magnetic moment of the Mn- and Fe-substituted MoS2 sheets can monotonously increase with the increase of tensile strain, while the magnetic moment of Co-, Ni-, Cu- and Zn-substituted MoS2 sheets initially increases and then decreases with the increase of tensile strain. An instructive mechanism was proposed to qualitatively explain the variation of magnetism with elastic strain. The finding of the magnetoelastic effect here is technologically important for the fabrication of strain-driven spin devices on MoS2 nanostructures, which allows us to go beyond the current scope limited to the spin devices within graphene and BN-based nanostructures.

  4. Enhanced Performance of Nanowire-Based All-TiO2 Solar Cells using Subnanometer-Thick Atomic Layer Deposited ZnO Embedded Layer

    International Nuclear Information System (INIS)

    Ghobadi, Amir; Yavuz, Halil I.; Ulusoy, T. Gamze; Icli, K. Cagatay; Ozenbas, Macit; Okyay, Ali K.

    2015-01-01

    In this paper, the effect of angstrom-thick atomic layer deposited (ALD) ZnO embedded layer on photovoltaic (PV) performance of Nanowire-Based All-TiO 2 solar cells has been systematically investigated. Our results indicate that by varying the thickness of ZnO layer the efficiency of the solar cell can be significantly changed. It is shown that the efficiency has its maximum for optimal thickness of 1 ALD cycle in which this ultrathin ZnO layer improves device performance through passivation of surface traps without hampering injection efficiency of photogenerated electrons. The mechanisms contributing to this unprecedented change in PV performance of the cell have been scrutinized and discussed

  5. Study of the embedded atom method of atomistic calculations for metals and alloys: Progress report, March 1, 1987-February 28, 1988

    International Nuclear Information System (INIS)

    Johnson, R.A.

    1987-11-01

    The relationships between the physical input and output of the Embedded Atom Method (EAM) used in atomistic calculations for metals and alloys and the model functions and parameters are being investigated. An analytic fcc EAM model has been derived based on short range approximations to the input functions in EAM and has been studied both analytically and numerically for the fcc lattice. This model has been extended to longer ranges and applied to both fcc and hcp metals. The correspondence between models based on density functional theory (EAM), tight binding methods, and effective medium theory has been reported. The reasons for difficulty in applying EAM to bcc metals is under study and a new form of alloy potential which retains general properties of pure metal potentials has been developed. 8 refs

  6. Two-Level Semantics and Code Generation

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis

    1988-01-01

    A two-level denotational metalanguage that is suitable for defining the semantics of Pascal-like languages is presented. The two levels allow for an explicit distinction between computations taking place at compile-time and computations taking place at run-time. While this distinction is perhaps...... not absolutely necessary for describing the input-output semantics of programming languages, it is necessary when issues such as data flow analysis and code generation are considered. For an example stack-machine, the authors show how to generate code for the run-time computations and still perform the compile...

  7. Quasicubic α-Fe{sub 2}O{sub 3} nanoparticles embedded in TiO{sub 2} thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, Aile [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu (Estonia); Seinberg, Liis [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Kozlova, Jekaterina [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu (Estonia); Link, Joosep [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Pikma, Piret [University of Tartu, Institute of Chemistry, Ravila 14A, 50411 Tartu (Estonia); Stern, Raivo [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Kukli, Kaupo [Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu (Estonia); Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland)

    2016-08-01

    Monodispersed quasicubic α-Fe{sub 2}O{sub 3} nanoparticles were synthesized from ferric nitrite (Fe(NO{sub 3}){sub 3}), N,N-dimethyl formamide and poly(N-vinyl-2-pyrrolidone). Layers of nanoparticles were attached to HF-etched Si substrates by dip coating and subsequently embedded in thin titanium oxide films grown by atomic layer deposition from TiCl{sub 4} and H{sub 2}O. The deposition of TiO{sub 2} onto Fe{sub 2}O{sub 3} nanoparticles covered the nanoparticles uniformly and anatase phase of TiO{sub 2} was observed in Si/Fe{sub 2}O{sub 3}/TiO{sub 2} nanostructures. In Si/Fe{sub 2}O{sub 3}/TiO{sub 2} nanostructure magnetic domains, observable by magnetic force microscopy, were formed and these nanostructures implied ferromagnetic-like behavior at room temperature with the saturative magnetization and coercivity of 10 kA/m. - Highlights: • Cubic-shaped iron oxide crystallites were supported by thin titanium oxide films. • The process chemistry applied allowed formation of heterogeneous composite. • Atomic layer deposition of titanium oxide on nanocubes was uniform and conformal. • The nanostructures formed can be regarded as magnetically susceptible materials.

  8. Embedded Systems

    Indian Academy of Sciences (India)

    Embedded system, micro-con- troller ... Embedded systems differ from general purpose computers in many ... Low cost: As embedded systems are extensively used in con- .... operating systems for the desktop computers where scheduling.

  9. Dynamical properties of a two-level system with arbitrary nonlinearities

    Indian Academy of Sciences (India)

    nication, information processing and quantum computing, such as in the investigation of quantum teleportation ... They con- sidered a two-level atom interacting with an undamped cavity initially in a coherent state. ... Because concurrence pro-.

  10. Strong nonlinearity-induced correlations for counterpropagating photons scattering on a two-level emitter

    DEFF Research Database (Denmark)

    Nysteen, Anders; McCutcheon, Dara; Mørk, Jesper

    2015-01-01

    We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could be quanti......We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could...

  11. Controlling the optical bistability and multistability in a two-level pumped-probe system

    International Nuclear Information System (INIS)

    Mahmoudi, Mohammad; Sahrai, Mostafa; Masoumeh Mousavi, Seyede

    2010-01-01

    We study the behavior of the optical bistability (OB) and multistability (OM) in a two-level pumped-probe atomic system by means of a unidirectional ring cavity. We show that the optical bistability in a two-level atomic system can be controlled by adjusting the intensity of the pump field and the detuning between two fields. We find that applying the pumping field decreases the threshold of the optical bistability.

  12. Memory Effect of Metal-Oxide-Silicon Capacitors with Self-Assembly Double-Layer Au Nanocrystals Embedded in Atomic-Layer-Deposited HfO2 Dielectric

    International Nuclear Information System (INIS)

    Yue, Huang; Hong-Yan, Gou; Qing-Qing, Sun; Shi-Jin, Ding; Wei, Zhang; Shi-Li, Zhang

    2009-01-01

    We report the chemical self-assembly growth of Au nanocrystals on atomic-layer-deposited HfO 2 films aminosilanized by (3-Aminopropyl)-trimethoxysilane aforehand for memory applications. The resulting Au nanocrystals show a density of about 4 × 10 11 cm −2 and a diameter range of 5–8nm. The metal-oxide-silicon capacitor with double-layer Au nanocrystals embedded in HfO 2 dielectric exhibits a large C – V hysteresis window of 11.9V for ±11 V gate voltage sweeps at 1 MHz, a flat-band voltage shift of 1.5 V after the electrical stress under 7 V for 1 ms, a leakage current density of 2.9 × 10 −8 A/cm −2 at 9 V and room temperature. Compared to single-layer Au nanocrystals, the double-layer Au nanocrystals increase the hysteresis window significantly, and the underlying mechanism is thus discussed

  13. Embedded Leverage

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Heje Pedersen, Lasse

    find that asset classes with embedded leverage offer low risk-adjusted returns and, in the cross-section, higher embedded leverage is associated with lower returns. A portfolio which is long low-embedded-leverage securities and short high-embedded-leverage securities earns large abnormal returns...

  14. Two-level tunneling systems in amorphous alumina

    Science.gov (United States)

    Lebedeva, Irina V.; Paz, Alejandro P.; Tokatly, Ilya V.; Rubio, Angel

    2014-03-01

    The decades of research on thermal properties of amorphous solids at temperatures below 1 K suggest that their anomalous behaviour can be related to quantum mechanical tunneling of atoms between two nearly equivalent states that can be described as a two-level system (TLS). This theory is also supported by recent studies on microwave spectroscopy of superconducting qubits. However, the microscopic nature of the TLS remains unknown. To identify structural motifs for TLSs in amorphous alumina we have performed extensive classical molecular dynamics simulations. Several bistable motifs with only one or two atoms jumping by considerable distance ~ 0.5 Å were found at T=25 K. Accounting for the surrounding environment relaxation was shown to be important up to distances ~ 7 Å. The energy asymmetry and barrier for the detected motifs lied in the ranges 0.5 - 2 meV and 4 - 15 meV, respectively, while their density was about 1 motif per 10 000 atoms. Tuning of motif asymmetry by strain was demonstrated with the coupling coefficient below 1 eV. The tunnel splitting for the symmetrized motifs was estimated on the order of 0.1 meV. The discovered motifs are in good agreement with the available experimental data. The financial support from the Marie Curie Fellowship PIIF-GA-2012-326435 (RespSpatDisp) is gratefully acknowledged.

  15. Atomistic study of two-level systems in amorphous silica

    Science.gov (United States)

    Damart, T.; Rodney, D.

    2018-01-01

    Internal friction is analyzed in an atomic-scale model of amorphous silica. The potential energy landscape of more than 100 glasses is explored to identify a sample of about 700 two-level systems (TLSs). We discuss the properties of TLSs, particularly their energy asymmetry and barrier as well as their deformation potential, computed as longitudinal and transverse averages of the full deformation potential tensors. The discrete sampling is used to predict dissipation in the classical regime. Comparison with experimental data shows a better agreement with poorly relaxed thin films than well relaxed vitreous silica, as expected from the large quench rates used to produce numerical glasses. The TLSs are categorized in three types that are shown to affect dissipation in different temperature ranges. The sampling is also used to discuss critically the usual approximations employed in the literature to represent the statistical properties of TLSs.

  16. Spontaneous emission spectrum of a four-level atom coupled by three kinds of reservoirs

    International Nuclear Information System (INIS)

    Yang Dong; Wang Jian; Zhang, Hanzhuang; Yao Jinbo

    2007-01-01

    A model of a four-level atom embedded in a double-band photonic crystal (PC) is presented. The atomic transitions from the upper two levels to the lower two levels are coupled by the same reservoir which is assumed in turn to be isotropic PC modes, anisotropic PC modes and free vacuum modes. The effects of the fine structure of the atomic ground state levels and the quantum interference on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown for the first time that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PC case. Quantum interference induces additional narrow spontaneous lines near the transition from the empty upper level to the lower levels

  17. Robust Deterministic Controlled Phase-Flip Gate and Controlled-Not Gate Based on Atomic Ensembles Embedded in Double-Sided Optical Cavities

    Science.gov (United States)

    Liu, A.-Peng; Cheng, Liu-Yong; Guo, Qi; Zhang, Shou

    2018-02-01

    We first propose a scheme for controlled phase-flip gate between a flying photon qubit and the collective spin wave (magnon) of an atomic ensemble assisted by double-sided cavity quantum systems. Then we propose a deterministic controlled-not gate on magnon qubits with parity-check building blocks. Both the gates can be accomplished with 100% success probability in principle. Atomic ensemble is employed so that light-matter coupling is remarkably improved by collective enhancement. We assess the performance of the gates and the results show that they can be faithfully constituted with current experimental techniques.

  18. Embedded defects

    International Nuclear Information System (INIS)

    Barriola, M.; Vachaspati, T.; Bucher, M.

    1994-01-01

    We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

  19. Numerical simulations for quantitative analysis of electrostatic interaction between atomic force microscopy probe and an embedded electrode within a thin dielectric: meshing optimization, sensitivity to potential distribution and impact of cantilever contribution

    Science.gov (United States)

    Azib, M.; Baudoin, F.; Binaud, N.; Villeneuve-Faure, C.; Bugarin, F.; Segonds, S.; Teyssedre, G.

    2018-04-01

    Recent experimental results demonstrated that an electrostatic force distance curve (EFDC) can be used for space charge probing in thin dielectric layers. A main advantage of the method is claimed to be its sensitivity to charge localization, which, however, needs to be substantiated by numerical simulations. In this paper, we have developed a model which permits us to compute an EFDC accurately by using the most sophisticated and accurate geometry for the atomic force microscopy probe. To avoid simplifications and in order to reproduce experimental conditions, the EFDC has been simulated for a system constituted of a polarized electrode embedded in a thin dielectric layer (SiN x ). The individual contributions of forces on the tip and on the cantilever have been analyzed separately to account for possible artefacts. The EFDC sensitivity to potential distribution is studied through the change in electrode shape, namely the width and the depth. Finally, the numerical results have been compared with experimental data.

  20. Moderation analysis using a two-level regression model.

    Science.gov (United States)

    Yuan, Ke-Hai; Cheng, Ying; Maxwell, Scott

    2014-10-01

    Moderation analysis is widely used in social and behavioral research. The most commonly used model for moderation analysis is moderated multiple regression (MMR) in which the explanatory variables of the regression model include product terms, and the model is typically estimated by least squares (LS). This paper argues for a two-level regression model in which the regression coefficients of a criterion variable on predictors are further regressed on moderator variables. An algorithm for estimating the parameters of the two-level model by normal-distribution-based maximum likelihood (NML) is developed. Formulas for the standard errors (SEs) of the parameter estimates are provided and studied. Results indicate that, when heteroscedasticity exists, NML with the two-level model gives more efficient and more accurate parameter estimates than the LS analysis of the MMR model. When error variances are homoscedastic, NML with the two-level model leads to essentially the same results as LS with the MMR model. Most importantly, the two-level regression model permits estimating the percentage of variance of each regression coefficient that is due to moderator variables. When applied to data from General Social Surveys 1991, NML with the two-level model identified a significant moderation effect of race on the regression of job prestige on years of education while LS with the MMR model did not. An R package is also developed and documented to facilitate the application of the two-level model.

  1. Experimental Hamiltonian identification for controlled two-level systems

    International Nuclear Information System (INIS)

    Schirmer, S.G.; Kolli, A.; Oi, D.K.L.

    2004-01-01

    We present a strategy to empirically determine the internal and control Hamiltonians for an unknown two-level system (black box) subject to various (piecewise constant) control fields when direct readout by measurement is limited to a single, fixed observable

  2. Memory characteristics of Au nanocrystals embedded in metal-oxide-semiconductor structure by using atomic-layer-deposited Al2O3 as control oxide

    International Nuclear Information System (INIS)

    Wang, C.-C.; Chiou, Y.-K.; Chang, C.-H.; Tseng, J.-Y.; Wu, L.-J.; Chen, C.-Y.; Wu, T.-B.

    2007-01-01

    The nonvolatile memory characteristics of metal-oxide-semiconductor (MOS) structures containing Au nanocrystals in the Al 2 O 3 /SiO 2 matrix were studied. In this work, we have demonstrated that the use of Al 2 O 3 as control oxide prepared by atomic-layer-deposition enhances the erase speed of the MOS capacitors. A giant capacitance-voltage hysteresis loop and a very short erase time which is lower than 1 ms can be obtained. Compared with the conventional floating-gate electrically erasable programmable read-only memories, the erase speed was promoted drastically. In addition, very low leakage current and large turn-around voltage resulting from electrons or holes stored in the Au nanocrystals were found in the current-voltage relation of the MOS capacitors

  3. Embedded Hardware

    CERN Document Server

    Ganssle, Jack G; Eady, Fred; Edwards, Lewin; Katz, David J; Gentile, Rick

    2007-01-01

    The Newnes Know It All Series takes the best of what our authors have written to create hard-working desk references that will be an engineer's first port of call for key information, design techniques and rules of thumb. Guaranteed not to gather dust on a shelf!. Circuit design using microcontrollers is both a science and an art. This book covers it all. It details all of the essential theory and facts to help an engineer design a robust embedded system. Processors, memory, and the hot topic of interconnects (I/O) are completely covered. Our authors bring a wealth of experience and ideas; thi

  4. Two-level convolution formula for nuclear structure function

    Science.gov (United States)

    Ma, Boqiang

    1990-05-01

    A two-level convolution formula for the nuclear structure function is derived in considering the nucleus as a composite system of baryon-mesons which are also composite systems of quark-gluons again. The results show that the European Muon Colaboration effect can not be explained by the nuclear effects as nucleon Fermi motion and nuclear binding contributions.

  5. Two-level convolution formula for nuclear structure function

    International Nuclear Information System (INIS)

    Ma Boqiang

    1990-01-01

    A two-level convolution formula for the nuclear structure function is derived in considering the nucleus as a composite system of baryon-mesons which are also composite systems of quark-gluons again. The results show that the European Muon Colaboration effect can not be explained by the nuclear effects as nucleon Fermi motion and nuclear binding contributions

  6. Stationary states of two-level open quantum systems

    International Nuclear Information System (INIS)

    Gardas, Bartlomiej; Puchala, Zbigniew

    2011-01-01

    A problem of finding stationary states of open quantum systems is addressed. We focus our attention on a generic type of open system: a qubit coupled to its environment. We apply the theory of block operator matrices and find stationary states of two-level open quantum systems under certain conditions applied on both the qubit and the surrounding.

  7. Entanglement of a nonlinear two two-level atoms interacting with ...

    Indian Academy of Sciences (India)

    S Abdel-Khalek

    2017-12-08

    Dec 8, 2017 ... [4,5], superdense coding [6], quantum cryptography. [7,8] and quantum metrology [9]. These quantum infor- mation tasks cannot be carried out by classical resources and they rely on entangled states. This recognition led to an intensive search for mathematical tools that would enable a proper quantification ...

  8. Quantum speed limit time of a two-level atom under different quantum feedback control

    Science.gov (United States)

    Yu, Min; Fang, Mao-Fa; Zou, Hong-Mei

    2018-01-01

    Not Available Project supported by the National Natural Science Foundation of China (Grant No. 11374096), Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2017B177), and the Scientific Research Project of Hunan Provincial Education Department, China (Grant No. 16C0949).

  9. Memory Effects in the Two-Level Model for Glasses

    Science.gov (United States)

    Aquino, Gerardo; Allahverdyan, Armen; Nieuwenhuizen, Theo M.

    2008-07-01

    We study an ensemble of two-level systems interacting with a thermal bath. This is a well-known model for glasses. The origin of memory effects in this model is a quasistationary but nonequilibrium state of a single two-level system, which is realized due to a finite-rate cooling and slow thermally activated relaxation. We show that single-particle memory effects, such as negativity of the specific heat under reheating, vanish for a sufficiently disordered ensemble. In contrast, a disordered ensemble displays a collective memory effect [similar to the Kovacs effect], where nonequilibrium features of the ensemble are monitored via a macroscopic observable. An experimental realization of the effect can be used to further assess the consistency of the model.

  10. Two-level method with coarse space size independent convergence

    Energy Technology Data Exchange (ETDEWEB)

    Vanek, P.; Brezina, M. [Univ. of Colorado, Denver, CO (United States); Tezaur, R.; Krizkova, J. [UWB, Plzen (Czech Republic)

    1996-12-31

    The basic disadvantage of the standard two-level method is the strong dependence of its convergence rate on the size of the coarse-level problem. In order to obtain the optimal convergence result, one is limited to using a coarse space which is only a few times smaller than the size of the fine-level one. Consequently, the asymptotic cost of the resulting method is the same as in the case of using a coarse-level solver for the original problem. Today`s two-level domain decomposition methods typically offer an improvement by yielding a rate of convergence which depends on the ratio of fine and coarse level only polylogarithmically. However, these methods require the use of local subdomain solvers for which straightforward application of iterative methods is problematic, while the usual application of direct solvers is expensive. We suggest a method diminishing significantly these difficulties.

  11. Franson Interference Generated by a Two-Level System

    Science.gov (United States)

    Peiris, M.; Konthasinghe, K.; Muller, A.

    2017-01-01

    We report a Franson interferometry experiment based on correlated photon pairs generated via frequency-filtered scattered light from a near-resonantly driven two-level semiconductor quantum dot. In contrast to spontaneous parametric down-conversion and four-wave mixing, this approach can produce single pairs of correlated photons. We have measured a Franson visibility as high as 66%, which goes beyond the classical limit of 50% and approaches the limit of violation of Bell's inequalities (70.7%).

  12. Mixing phases of unstable two-level systems

    International Nuclear Information System (INIS)

    Sokolov, V.V.; Brentano, P. von.

    1993-01-01

    An unstable two-level system decaying into an arbitrary number of channels is considered. It is shown that the mixing phases of the two overlapping resonances can be expressed in the terms of their partial widths and one additional universal mixing parameter. Some applications to a doublet of 2 + resonances in 8 Be and to the ρ-ω systems are considered. 18 refs

  13. Two-level systems driven by large-amplitude fields

    Science.gov (United States)

    Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.

    2009-03-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.

  14. Perturbation Theory for Open Two-Level Nonlinear Quantum Systems

    International Nuclear Information System (INIS)

    Zhang Zhijie; Jiang Dongguang; Wang Wei

    2011-01-01

    Perturbation theory is an important tool in quantum mechanics. In this paper, we extend the traditional perturbation theory to open nonlinear two-level systems, treating decoherence parameter γ as a perturbation. By this virtue, we give a perturbative solution to the master equation, which describes a nonlinear open quantum system. The results show that for small decoherence rate γ, the ratio of the nonlinear rate C to the tunneling coefficient V (i.e., r = C/V) determines the validity of the perturbation theory. For small ratio r, the perturbation theory is valid, otherwise it yields wrong results. (general)

  15. Modal intersection types, two-level languages, and staged synthesis

    DEFF Research Database (Denmark)

    Henglein, Fritz; Rehof, Jakob

    2016-01-01

    -linguistic framework for staged program synthesis, where metaprograms are automatically synthesized which, when executed, generate code in a target language. We survey the basic theory of staged synthesis and illustrate by example how a two-level language theory specialized from λ∩ ⎕ can be used to understand......A typed λ-calculus, λ∩ ⎕, is introduced, combining intersection types and modal types. We develop the metatheory of λ∩ ⎕, with particular emphasis on the theory of subtyping and distributivity of the modal and intersection type operators. We describe how a stratification of λ∩ ⎕ leads to a multi...... the process of staged synthesis....

  16. The embedded operating system project

    Science.gov (United States)

    Campbell, R. H.

    1984-01-01

    This progress report describes research towards the design and construction of embedded operating systems for real-time advanced aerospace applications. The applications concerned require reliable operating system support that must accommodate networks of computers. The report addresses the problems of constructing such operating systems, the communications media, reconfiguration, consistency and recovery in a distributed system, and the issues of realtime processing. A discussion is included on suitable theoretical foundations for the use of atomic actions to support fault tolerance and data consistency in real-time object-based systems. In particular, this report addresses: atomic actions, fault tolerance, operating system structure, program development, reliability and availability, and networking issues. This document reports the status of various experiments designed and conducted to investigate embedded operating system design issues.

  17. Two-level schemes for the advection equation

    Science.gov (United States)

    Vabishchevich, Petr N.

    2018-06-01

    The advection equation is the basis for mathematical models of continuum mechanics. In the approximate solution of nonstationary problems it is necessary to inherit main properties of the conservatism and monotonicity of the solution. In this paper, the advection equation is written in the symmetric form, where the advection operator is the half-sum of advection operators in conservative (divergent) and non-conservative (characteristic) forms. The advection operator is skew-symmetric. Standard finite element approximations in space are used. The standard explicit two-level scheme for the advection equation is absolutely unstable. New conditionally stable regularized schemes are constructed, on the basis of the general theory of stability (well-posedness) of operator-difference schemes, the stability conditions of the explicit Lax-Wendroff scheme are established. Unconditionally stable and conservative schemes are implicit schemes of the second (Crank-Nicolson scheme) and fourth order. The conditionally stable implicit Lax-Wendroff scheme is constructed. The accuracy of the investigated explicit and implicit two-level schemes for an approximate solution of the advection equation is illustrated by the numerical results of a model two-dimensional problem.

  18. Two-level systems driven by large-amplitude fields

    International Nuclear Information System (INIS)

    Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.; Nori, Franco

    2007-01-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems

  19. Embedded Processor Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Embedded Processor Laboratory provides the means to design, develop, fabricate, and test embedded computers for missile guidance electronics systems in support...

  20. Ramsey interferometry with a two-level generalized Tonks-Girardeau gas

    International Nuclear Information System (INIS)

    Mousavi, S. V.; Campo, A. del; Lizuain, I.; Muga, J. G.

    2007-01-01

    We propose a solvable generalization of the Tonks-Girardeau model that describes a coherent one-dimensional (1D) gas of cold two-level bosons which interact with two external fields in a Ramsey interferometer. They also interact among themselves by idealized, infinitely strong contact potentials, with interchange of momentum and internal state. We study the corresponding Ramsey fringes and the quantum projection noise which, essentially unaffected by the interactions, remains that for ideal bosons. The dual system of this gas, an ideal gas of two-level fermions coupled by the interaction with the separated fields, produces the same fringes and noise fluctuations. The cases of time-separated and spatially separated fields are studied. For spatially separated fields the fringes may be broadened slightly by increasing the number of particles, but only for large particle numbers far from present experiments with Tonks-Girardeau gases. The uncertainty in the determination of the atomic transition frequency diminishes, essentially with the inverse root of the particle number. The difficulties to implement the model experimentally and possible shortcomings of strongly interacting 1D gases for frequency standards and atomic clocks are discussed

  1. Two-level modelling of real estate taxtation

    DEFF Research Database (Denmark)

    Gall, Jaroslav; Stubkjær, Erik

    2006-01-01

    Real estate taxes recurrently attract attention, because they are a source of potentially increased revenue for local and national government. Most experts agree that it is necessary to switch from using normative values for taxation to a market-value-based taxation of real property with computer......-assisted mass valuation, witch benefit from use of value maps. In Czech Republic, efforts have been made to adopt current tax policy goals, but improvements are still needed. The paper aims at supporting the current improvement process towards a market based system. It presents models, which describe aspects...... of the present Czech property tax system. A proposal for the future system focuses on the value map component. The described change depends on political involvement. This political activity is modelled as well. The hypothesis is that the two-level modelling effort enhances the change process by providing...

  2. Conceptualizing Embedded Configuration

    DEFF Research Database (Denmark)

    Oddsson, Gudmundur Valur; Hvam, Lars; Lysgaard, Ole

    2006-01-01

    and services. The general idea can be named embedded configuration. In this article we intend to conceptualize embedded configuration, what it is and is not. The difference between embedded configuration, sales configuration and embedded software is explained. We will look at what is needed to make embedded...... configuration systems. That will include requirements to product modelling techniques. An example with consumer electronics will illuminate the elements of embedded configuration in settings that most can relate to. The question of where embedded configuration would be relevant is discussed, and the current...

  3. Pixel detector readout electronics with two-level discriminator scheme

    International Nuclear Information System (INIS)

    Pengg, F.

    1998-01-01

    In preparation for a silicon pixel detector with more than 3,000 readout channels per chip for operation at the future large hadron collider (LHC) at CERN the analog front end of the readout electronics has been designed and measured on several test-arrays with 16 by 4 cells. They are implemented in the HP 0.8 microm process but compatible with the design rules of the radiation hard Honeywell 0.8 microm bulk process. Each cell contains bump bonding pad, preamplifier, discriminator and control logic for masking and testing within a layout area of only 50 microm by 140 microm. A new two-level discriminator scheme has been implemented to cope with the problems of time-walk and interpixel cross-coupling. The measured gain of the preamplifier is 900 mV for a minimum ionizing particle (MIP, about 24,000 e - for a 300 microm thick Si-detector) with a return to baseline within 750 ns for a 1 MIP input signal. The full readout chain (without detector) shows an equivalent noise charge to 60e - r.m.s. The time-walk, a function of the separation between the two threshold levels, is measured to be 22 ns at a separation of 1,500 e - , which is adequate for the 40 MHz beam-crossing frequency at the LHC. The interpixel cross-coupling, measured with a 40fF coupling capacitance, is less than 3%. A single cell consumes 35 microW at 3.5 V supply voltage

  4. Properties of the localized field emitted from degenerate Λ-type atoms in photonic crystals

    International Nuclear Information System (INIS)

    Foroozani, N.; Golshan, M. M.; Mahjoei, M.

    2007-01-01

    The spontaneous emission from a degenerate Λ-type three-level atom, embedded in a photonic crystal, is studied. The emitted field, as a function of time and position, is calculated by solving the three coupled differential equations governing the amplitudes. We show that the spontaneously emitted field is characterized by three components (as in the case of two-level and V-type atoms): a localized part, a traveling part, and a t -3/2 decaying part. Our calculations indicate that under specific conditions the atoms do not emit propagating fields, while the localized field, having shorter localization length and time, is intensified. As a consequence, the population of the upper level, after a short period of oscillations, approaches a constant value. It is also shown that this steady value, under the same conditions, is much larger than its counterpart in V-type atoms

  5. Dynamical Evolution of an Effective Two-Level System with {\\mathscr{P}}{\\mathscr{T}} Symmetry

    Science.gov (United States)

    Du, Lei; Xu, Zhihao; Yin, Chuanhao; Guo, Liping

    2018-05-01

    We investigate the dynamics of parity- and time-reversal (PT ) symmetric two-energy-level atoms in the presence of two optical and a radio-frequency (rf) fields. The strength and relative phase of fields can drive the system from unbroken to broken PT symmetric regions. Compared with the Hermitian model, Rabi-type oscillation is still observed, and the oscillation characteristics are also adjusted by the strength and relative phase in the region of unbroken PT symmetry. At exception point (EP), the oscillation breaks down. To better understand the underlying properties we study the effective Bloch dynamics and find the emergence of the z components of the fixed points is the feature of the PT symmetry breaking and the projections in x-y plane can be controlled with high flexibility compared with the standard two-level system with PT symmetry. It helps to study the dynamic behavior of the complex PT symmetric model.

  6. Dynamical model of coherent circularly polarized optical pulse interactions with two-level quantum systems

    International Nuclear Information System (INIS)

    Slavcheva, G.; Hess, O.

    2005-01-01

    We propose and develop a method for theoretical description of circularly (elliptically) polarized optical pulse resonant coherent interactions with two-level atoms. The method is based on the time-evolution equations of a two-level quantum system in the presence of a time-dependent dipole perturbation for electric dipole transitions between states with total angular-momentum projection difference (ΔJ z =±1) excited by a circularly polarized electromagnetic field [Feynman et al., J. Appl. Phys. 28, 49 (1957)]. The adopted real-vector representation approach allows for coupling with the vectorial Maxwell's equations for the optical wave propagation and thus the resulting Maxwell pseudospin equations can be numerically solved in the time domain without any approximations. The model permits a more exact study of the ultrafast coherent pulse propagation effects taking into account the vector nature of the electromagnetic field and hence the polarization state of the optical excitation. We demonstrate self-induced transparency effects and formation of polarized solitons. The model represents a qualitative extension of the well-known optical Maxwell-Bloch equations valid for linearly polarized light and a tool for studying coherent quantum control mechanisms

  7. Polymorphic Embedding of DSLs

    DEFF Research Database (Denmark)

    Hofer, Christian; Ostermann, Klaus; Rendel, Tillmann

    2008-01-01

    propose polymorphic embedding of DSLs, where many different interpretations of a DSL can be provided as reusable components, and show how polymorphic embedding can be realized in the programming language Scala. With polymorphic embedding, the static type-safety, modularity, composability and rapid...

  8. SPONGY (SPam ONtoloGY: Email Classification Using Two-Level Dynamic Ontology

    Directory of Open Access Journals (Sweden)

    Seongwook Youn

    2014-01-01

    Full Text Available Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user’s background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1 to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2 to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance.

  9. A Two-Level Task Scheduler on Multiple DSP System for OpenCL

    Directory of Open Access Journals (Sweden)

    Li Tian

    2014-04-01

    Full Text Available This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.

  10. SPONGY (SPam ONtoloGY): email classification using two-level dynamic ontology.

    Science.gov (United States)

    Youn, Seongwook

    2014-01-01

    Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user's background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1) to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2) to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance.

  11. SPONGY (SPam ONtoloGY): Email Classification Using Two-Level Dynamic Ontology

    Science.gov (United States)

    2014-01-01

    Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user's background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1) to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2) to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance. PMID:25254240

  12. Polarizable Density Embedding Coupled Cluster Method

    DEFF Research Database (Denmark)

    Hršak, Dalibor; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob

    2018-01-01

    by an embedding potential consisting of a set of fragment densities obtained from calculations on isolated fragments with a quantum-chemistry method such as Hartree-Fock (HF) or Kohn-Sham density functional theory (KS-DFT) and dressed with a set of atom-centered anisotropic dipole-dipole polarizabilities...

  13. Single atom oscillations

    International Nuclear Information System (INIS)

    Wiorkowski, P.; Walther, H.

    1990-01-01

    Modern methods of laser spectroscopy allow the study of single atoms or ions in an unperturbed environment. This has opened up interesting new experiments, among them the detailed study of radiation-atom coupling. In this paper, the following two experiments dealing with this problem are reviewed: the single-atom maser and the study of the resonance fluorescence of a single stored ion. The simplest and most fundamental system for studying radiation-matter coupling is a single two-level atom interacting with a single mode of an electromagnetic field in a cavity. This problem received a great deal of attention shortly after the maser was invented

  14. The embedded operating system project

    Science.gov (United States)

    Campbell, R. H.

    1985-01-01

    The design and construction of embedded operating systems for real-time advanced aerospace applications was investigated. The applications require reliable operating system support that must accommodate computer networks. Problems that arise in the construction of such operating systems, reconfiguration, consistency and recovery in a distributed system, and the issues of real-time processing are reported. A thesis that provides theoretical foundations for the use of atomic actions to support fault tolerance and data consistency in real-time object-based system is included. The following items are addressed: (1) atomic actions and fault-tolerance issues; (2) operating system structure; (3) program development; (4) a reliable compiler for path Pascal; and (5) mediators, a mechanism for scheduling distributed system processes.

  15. Deep diode atomic battery

    International Nuclear Information System (INIS)

    Anthony, T.R.; Cline, H.E.

    1977-01-01

    A deep diode atomic battery is made from a bulk semiconductor crystal containing three-dimensional arrays of columnar and lamellar P-N junctions. The battery is powered by gamma rays and x-ray emission from a radioactive source embedded in the interior of the semiconductor crystal

  16. Embedding beyond electrostatics

    DEFF Research Database (Denmark)

    Nåbo, Lina J.; Olsen, Jógvan Magnus Haugaard; Holmgaard List, Nanna

    2016-01-01

    We study excited states of cholesterol in solution and show that, in this specific case, solute wave-function confinement is the main effect of the solvent. This is rationalized on the basis of the polarizable density embedding scheme, which in addition to polarizable embedding includes non-electrostatic...... repulsion that effectively confines the solute wave function to its cavity. We illustrate how the inclusion of non-electrostatic repulsion results in a successful identification of the intense π → π∗ transition, which was not possible using an embedding method that only includes electrostatics....... This underlines the importance of non-electrostatic repulsion in quantum-mechanical embedding-based methods....

  17. Embedded systems handbook

    CERN Document Server

    Zurawski, Richard

    2005-01-01

    Embedded systems are nearly ubiquitous, and books on individual topics or components of embedded systems are equally abundant. Unfortunately, for those designers who thirst for knowledge of the big picture of embedded systems there is not a drop to drink. Until now. The Embedded Systems Handbook is an oasis of information, offering a mix of basic and advanced topics, new solutions and technologies arising from the most recent research efforts, and emerging trends to help you stay current in this ever-changing field.With preeminent contributors from leading industrial and academic institutions

  18. Web Server Embedded System

    Directory of Open Access Journals (Sweden)

    Adharul Muttaqin

    2014-07-01

    Full Text Available Abstrak Embedded sistem saat ini menjadi perhatian khusus pada teknologi komputer, beberapa sistem operasi linux dan web server yang beraneka ragam juga sudah dipersiapkan untuk mendukung sistem embedded, salah satu aplikasi yang dapat digunakan dalam operasi pada sistem embedded adalah web server. Pemilihan web server pada lingkungan embedded saat ini masih jarang dilakukan, oleh karena itu penelitian ini dilakukan dengan menitik beratkan pada dua buah aplikasi web server yang tergolong memiliki fitur utama yang menawarkan “keringanan” pada konsumsi CPU maupun memori seperti Light HTTPD dan Tiny HTTPD. Dengan menggunakan parameter thread (users, ramp-up periods, dan loop count pada stress test embedded system, penelitian ini menawarkan solusi web server manakah diantara Light HTTPD dan Tiny HTTPD yang memiliki kecocokan fitur dalam penggunaan embedded sistem menggunakan beagleboard ditinjau dari konsumsi CPU dan memori. Hasil penelitian menunjukkan bahwa dalam hal konsumsi CPU pada beagleboard embedded system lebih disarankan penggunaan Light HTTPD dibandingkan dengan tiny HTTPD dikarenakan terdapat perbedaan CPU load yang sangat signifikan antar kedua layanan web tersebut Kata kunci: embedded system, web server Abstract Embedded systems are currently of particular concern in computer technology, some of the linux operating system and web server variegated also prepared to support the embedded system, one of the applications that can be used in embedded systems are operating on the web server. Selection of embedded web server on the environment is still rarely done, therefore this study was conducted with a focus on two web application servers belonging to the main features that offer a "lightness" to the CPU and memory consumption as Light HTTPD and Tiny HTTPD. By using the parameters of the thread (users, ramp-up periods, and loop count on a stress test embedded systems, this study offers a solution of web server which between the Light

  19. Embedded systems handbook networked embedded systems

    CERN Document Server

    Zurawski, Richard

    2009-01-01

    Considered a standard industry resource, the Embedded Systems Handbook provided researchers and technicians with the authoritative information needed to launch a wealth of diverse applications, including those in automotive electronics, industrial automated systems, and building automation and control. Now a new resource is required to report on current developments and provide a technical reference for those looking to move the field forward yet again. Divided into two volumes to accommodate this growth, the Embedded Systems Handbook, Second Edition presents a comprehensive view on this area

  20. The data embedding method

    Energy Technology Data Exchange (ETDEWEB)

    Sandford, M.T. II; Bradley, J.N.; Handel, T.G.

    1996-06-01

    Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in Microsoft{reg_sign} bitmap (.BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed {open_quote}steganography.{close_quote} Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or {open_quote}lossy{close_quote} compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is in data an analysis algorithm.

  1. Smart Multicore Embedded Systems

    DEFF Research Database (Denmark)

    This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where ve...

  2. Embedded engineering education

    CERN Document Server

    Kaštelan, Ivan; Temerinac, Miodrag; Barak, Moshe; Sruk, Vlado

    2016-01-01

    This book focuses on the outcome of the European research project “FP7-ICT-2011-8 / 317882: Embedded Engineering Learning Platform” E2LP. Additionally, some experiences and researches outside this project have been included. This book provides information about the achieved results of the E2LP project as well as some broader views about the embedded engineering education. It captures project results and applications, methodologies, and evaluations. It leads to the history of computer architectures, brings a touch of the future in education tools and provides a valuable resource for anyone interested in embedded engineering education concepts, experiences and material. The book contents 12 original contributions and will open a broader discussion about the necessary knowledge and appropriate learning methods for the new profile of embedded engineers. As a result, the proposed Embedded Computer Engineering Learning Platform will help to educate a sufficient number of future engineers in Europe, capable of d...

  3. Embedded Linux in het onderwijs

    NARCIS (Netherlands)

    Dr Ruud Ermers

    2008-01-01

    Embedded Linux wordt bij steeds meer grote bedrijven ingevoerd als embedded operating system. Binnen de opleiding Technische Informatica van Fontys Hogeschool ICT is Embedded Linux geïntroduceerd in samenwerking met het lectoraat Architectuur van Embedded Systemen. Embedded Linux is als vakgebied

  4. Cascaded two-photon nonlinearity in a one-dimensional waveguide with multiple two-level emitters

    Science.gov (United States)

    Roy, Dibyendu

    2013-01-01

    We propose and theoretically investigate a model to realize cascaded optical nonlinearity with few atoms and photons in one-dimension (1D). The optical nonlinearity in our system is mediated by resonant interactions of photons with two-level emitters, such as atoms or quantum dots in a 1D photonic waveguide. Multi-photon transmission in the waveguide is nonreciprocal when the emitters have different transition energies. Our theory provides a clear physical understanding of the origin of nonreciprocity in the presence of cascaded nonlinearity. We show how various two-photon nonlinear effects including spatial attraction and repulsion between photons, background fluorescence can be tuned by changing the number of emitters and the coupling between emitters (controlled by the separation). PMID:23948782

  5. Brauer type embedding problems

    CERN Document Server

    Ledet, Arne

    2005-01-01

    This monograph is concerned with Galois theoretical embedding problems of so-called Brauer type with a focus on 2-groups and on finding explicit criteria for solvability and explicit constructions of the solutions. The advantage of considering Brauer type embedding problems is their comparatively simple condition for solvability in the form of an obstruction in the Brauer group of the ground field. This book presupposes knowledge of classical Galois theory and the attendant algebra. Before considering questions of reducing the embedding problems and reformulating the solvability criteria, the

  6. Time-dependent embedding

    OpenAIRE

    Inglesfield, J. E.

    2007-01-01

    A method of solving the time-dependent Schr\\"odinger equation is presented, in which a finite region of space is treated explicitly, with the boundary conditions for matching the wave-functions on to the rest of the system replaced by an embedding term added on to the Hamiltonian. This time-dependent embedding term is derived from the Fourier transform of the energy-dependent embedding potential, which embeds the time-independent Schr\\"odinger equation. Results are presented for a one-dimensi...

  7. Test of Bell's inequality using the one-atom micromaser

    Indian Academy of Sciences (India)

    However, the advantages of using two-level Rydberg atoms for test- ing Bell's inequalities are ... A couple of two-level. Rydberg atoms ... of decoherence on atomic statistics obtained through numerical analysis is presented inЬ4 where we also ...

  8. Electronics for embedded systems

    CERN Document Server

    Bindal, Ahmet

    2017-01-01

    This book provides semester-length coverage of electronics for embedded systems, covering most common analog and digital circuit-related issues encountered while designing embedded system hardware. It is written for students and young professionals who have basic circuit theory background and want to learn more about passive circuits, diode and bipolar transistor circuits, the state-of-the-art CMOS logic family and its interface with older logic families such as TTL, sensors and sensor physics, operational amplifier circuits to condition sensor signals, data converters and various circuits used in electro-mechanical device control in embedded systems. The book also provides numerous hardware design examples by integrating the topics learned in earlier chapters. The last chapter extensively reviews the combinational and sequential logic design principles to be able to design the digital part of embedded system hardware.

  9. Embedded Fragments Registry (EFR)

    Data.gov (United States)

    Department of Veterans Affairs — In 2009, the Department of Defense estimated that approximately 40,000 service members who served in OEF/OIF may have embedded fragment wounds as the result of small...

  10. Smart Multicore Embedded Systems

    DEFF Research Database (Denmark)

    This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where very...... specificities of various embedded systems from different industries. Parallel programming tool-chains are described that take as input parameters both the application and the platform model, then determine relevant transformations and mapping decisions on the concrete platform, minimizing user intervention...... and hiding the difficulties related to the correct and efficient use of memory hierarchy and low level code generation. Describes tools and programming models for multicore embedded systems Emphasizes throughout performance per watt scalability Discusses realistic limits of software parallelization Enables...

  11. Optimal control of quantum gates and suppression of decoherence in a system of interacting two-level particles

    International Nuclear Information System (INIS)

    Grace, Matthew; Brif, Constantin; Rabitz, Herschel; Walmsley, Ian A; Kosut, Robert L; Lidar, Daniel A

    2007-01-01

    Methods of optimal control are applied to a model system of interacting two-level particles (e.g., spin-half atomic nuclei or electrons or two-level atoms) to produce high-fidelity quantum gates while simultaneously negating the detrimental effect of decoherence. One set of particles functions as the quantum information processor, whose evolution is controlled by a time-dependent external field. The other particles are not directly controlled and serve as an effective environment, coupling to which is the source of decoherence. The control objective is to generate target one- and two-qubit unitary gates in the presence of strong environmentally-induced decoherence and under physically motivated restrictions on the control field. The quantum-gate fidelity, expressed in terms of a novel state-independent distance measure, is maximized with respect to the control field using combined genetic and gradient algorithms. The resulting high-fidelity gates demonstrate the feasibility of precisely guiding the quantum evolution via optimal control, even when the system complexity is exacerbated by environmental coupling. It is found that the gate duration has an important effect on the control mechanism and resulting fidelity. An analysis of the sensitivity of the gate performance to random variations in the system parameters reveals a significant degree of robustness attained by the optimal control solutions

  12. ONE-DIMENSIONAL ORDERING OF IN ATOMS IN A CU(100) SURFACE

    NARCIS (Netherlands)

    BREEMAN, M; BARKEMA, GT; BOERMA, DO

    1994-01-01

    A Monte Carlo study of the ordering of In atoms embedded in the top layer of a Cu(100) surface is presented. The interaction energies between the In and Cu atoms were derived from atom-embedding calculations, with Finnis-Sinclair potentials. It was found that the interaction between In atoms in the

  13. Quantum theory of phonon-mediated decoherence and relaxation of two-level systems in a structured electromagnetic reservoir

    Science.gov (United States)

    Roy, Chiranjeeb

    In this thesis we study the role of nonradiative degrees of freedom on quantum optical properties of mesoscopic quantum dots placed in the structured electromagnetic reservoir of a photonic crystal. We derive a quantum theory of the role of acoustic and optical phonons in modifying the optical absorption lineshape, polarization dynamics, and population dynamics of a two-level atom (quantum dot) in the "colored" electromagnetic vacuum of a photonic band gap (PBG) material. This is based on a microscopic Hamiltonian describing both radiative and vibrational processes quantum mechanically. Phonon sidebands in an ordinary electromagnetic reservoir are recaptured in a simple model of optical phonons using a mean-field factorization of the atomic and lattice displacement operators. Our formalism is then used to treat the non-Markovian dynamics of the same system within the structured electromagnetic density of states of a photonic crystal. We elucidate the extent to which phonon-assisted decay limits the lifetime of a single photon-atom bound state and derive the modified spontaneous emission dynamics due to coupling to various phonon baths. We demonstrate that coherent interaction with undamped phonons can lead to enhanced lifetime of a photon-atom bound state in a PBG by (i) dephasing and reducing the transition electric dipole moment of the atom and (ii) reducing the quantum mechanical overlap of the state vectors of the excited and ground state (polaronic shift). This results in reduction of the steady-state atomic polarization but an increase in the fractionalized upper state population in the photon-atom bound state. We demonstrate, on the other hand, that the lifetime of the photon-atom bound state in a PBG is limited by the lifetime of phonons due to lattice anharmonicities (break-up of phonons into lower energy phonons) and purely nonradiative decay. We demonstrate how these additional damping effects limit the extent of the polaronic (Franck-Condon) shift of

  14. Anisotropic Transport of Electrons in a Novel FET Channel with Chains of InGaAs Nano-Islands Embedded along Quasi-Periodic Multi-Atomic Steps on Vicinal (111)B GaAs

    International Nuclear Information System (INIS)

    Akiyama, Y.; Kawazu, T.; Noda, T.; Sakaki, H.

    2010-01-01

    We have studied electron transport in n-AlGaAs/GaAs heterojunction FET channels, in which chains of InGaAs nano-islands are embedded along quasi-periodic steps. By using two samples, conductance G para (V g ) parallel to the steps and G perp (V g ) perpendicular to them were measured at 80 K as functions of gate voltage V g . At sufficiently high V g , G para at 80 K is several times as high as G perp , which manifests the anisotropic two-dimensional transport of electrons. When V g is reduced to -0.7 V, G perp almost vanishes, while Gpara stays sizable unless V g is set below -0.8 V. These results indicate that 'inter-chain' barriers play stronger roles than 'intra-chain' barriers.

  15. Potential-functional embedding theory for molecules and materials.

    Science.gov (United States)

    Huang, Chen; Carter, Emily A

    2011-11-21

    We introduce a potential-functional embedding theory by reformulating a recently proposed density-based embedding theory in terms of functionals of the embedding potential. This potential-functional based theory completes the dual problem in the context of embedding theory for which density-functional embedding theory has existed for two decades. With this potential-functional formalism, it is straightforward to solve for the unique embedding potential shared by all subsystems. We consider charge transfer between subsystems and discuss how to treat fractional numbers of electrons in subsystems. We show that one is able to employ different energy functionals for different subsystems in order to treat different regions with theories of different levels of accuracy, if desired. The embedding potential is solved for by directly minimizing the total energy functional, and we discuss how to efficiently calculate the gradient of the total energy functional with respect to the embedding potential. Forces are also derived, thereby making it possible to optimize structures and account for nuclear dynamics. We also extend the theory to spin-polarized cases. Numerical examples of the theory are given for some homo- and hetero-nuclear diatomic molecules and a more complicated test of a six-hydrogen-atom chain. We also test our theory in a periodic bulk environment with calculations of basic properties of bulk NaCl, by treating each atom as a subsystem. Finally, we demonstrate the theory for water adsorption on the MgO(001)surface.

  16. Resonance Fluorescence of a Two-Level Atom Near a Metal Surface. II. Case of a Strong Driving Field,

    Science.gov (United States)

    1984-02-01

    XYH thanks Prof. M. G. Raymer for a useful discussion. REFERENCES 1. X. Y. Huang, J. Lin and T. F. George, J. Chem. Phys., 80, 893 (1984). 2. X. Y...Mollow, Phys. Rev. A, 15, 1023 (1977). 12. J. L. Carlsten, A. Sz6ke and M. G. Raymer , Phys. Rev. A, 15, 1029 (1977). 13. H. Kuhn, J. Chem. Phys. 53, 101...Evanston, Illinois 60201 Austin, Texas 78712 Dr. Robert M. Hexter Dr. R. P. Van Duyne Department of Chemistry Chemistry Department University of Minnesota

  17. Observation of the widening and shifting of EIT windows in a quasi-degenerate two-level atomic system

    International Nuclear Information System (INIS)

    Dong Yabin; Zhang Junxiang; Wang Haihong; Gao Jiangrui

    2006-01-01

    Widening and shifting the EIT windows in a closed transition F e = 2 ↔ F g = 3 driven by linearly polarized coupling lights and probed by circularly polarized lights are observed in Cs vapour. It is shown that by increasing the strength of magnetic field i.e. Zeeman splitting in the upper and lower levels, the electromagnetically induced transparency window is divided into two windows and the EIT maxima are shifted away from the zero detuning. In the contrast, if the strength of the magnetic field is fixed and the Rabi frequency of coupling beam is increased, the two EIT windows become wider, and the gap between the two EIT windows becomes smaller and smaller. These effects are also theoretically discussed and they are qualitatively in agreement with the theoretical results

  18. Embedded Systems Design: Optimization Challenges

    DEFF Research Database (Denmark)

    Pop, Paul

    2005-01-01

    Summary form only given. Embedded systems are everywhere: from alarm clocks to PDAs, from mobile phones to cars, almost all the devices we use are controlled by embedded systems. Over 99% of the microprocessors produced today are used in embedded systems, and recently the number of embedded systems...

  19. Smart multicore embedded systems

    CERN Document Server

    Bertels, Koen; Karlsson, Sven; Pacull, François

    2014-01-01

    This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where very often they are forced to rewrite sequential programs into parallel software, taking into account all the low level features and peculiarities of the underlying platforms. Readers will benefit from these authors’ approach, which takes into account both the application requirements and the platform specificities of various embedded systems from different industries. Parallel programming tool-chains are described that take as input parameters both the application and the platform model, then determine relevant transformations and mapping decisions on the concrete platform, minimizing user intervention and hiding the difficulties related to the correct and efficient use of memory hierarchy and low level code generati...

  20. Two-step values for games with two-level communication structure

    NARCIS (Netherlands)

    Béal, Silvain; Khmelnitskaya, Anna Borisovna; Solal, Philippe

    TU games with two-level communication structure, in which a two-level communication structure relates fundamentally to the given coalition structure and consists of a communication graph on the collection of the a priori unions in the coalition structure, as well as a collection of communication

  1. Polarizable Density Embedding

    DEFF Research Database (Denmark)

    Olsen, Jógvan Magnus Haugaard; Steinmann, Casper; Ruud, Kenneth

    2015-01-01

    We present a new QM/QM/MM-based model for calculating molecular properties and excited states of solute-solvent systems. We denote this new approach the polarizable density embedding (PDE) model and it represents an extension of our previously developed polarizable embedding (PE) strategy. The PDE...... model is a focused computational approach in which a core region of the system studied is represented by a quantum-chemical method, whereas the environment is divided into two other regions: an inner and an outer region. Molecules belonging to the inner region are described by their exact densities...

  2. Thermal Conductivity of Carbon Nanotubes Embedded in Solids

    Institute of Scientific and Technical Information of China (English)

    CAO Bing-Yang; HOU Quan-Wen

    2008-01-01

    @@ A carbon-nanotube-atom fixed and activated scheme of non-equilibrium molecular dynamics simulations is put forward to extract the thermal conductivity of carbon nanotubes (CNTs) embedded in solid argon. Though a 6.5% volume fraction of CNTs increases the composite thermal conductivity to about twice as much as that of the pure basal material, the thermal conductivity of CNTs embedded in solids is found to be decreased by 1/8-1/5with reference to that of pure ones. The decrease of the intrinsic thermal conductivity of the solid-embedded CNTs and the thermal interface resistance are demonstrated to be responsible for the results.

  3. Quality of Service-Driven Requirements Analyses for Component Composition: A Two-Level Grammar++ Approach

    National Research Council Canada - National Science Library

    Liu, Shih-Hsi; Cao, Fei; Bryant, Barrett R; Gray, Jeff; Raje, Rajeev R; Olson, Andrew M; Auguston, Mikhail

    2005-01-01

    .... When applied to Distributed Real-Time and Embedded (DRE) systems, which components to assemble and how to assemble them are determined not only from functional correctness criteria but also assurance of the system's quality of service (QoS...

  4. Embedding JIT into MRP

    NARCIS (Netherlands)

    Flapper, S.D.P.; Miltenburg, G.J.; Wijngaard, J.

    1991-01-01

    Today many companies who are using MRP production control systems are investigating how they can produce some or all of their products using just-in time (JIT) principles. They wonder to what extent MRP can provide support for JIT production. This paper describes how JIT can be embedded into MRP. A

  5. Embedded Multimaterial Extrusion Bioprinting

    NARCIS (Netherlands)

    Rocca, Marco; Fragasso, Alessio; Liu, Wanjun; Heinrich, Marcel A.; Zhang, Yu Shrike

    Embedded extrusion bioprinting allows for the generation of complex structures that otherwise cannot be achieved with conventional layer-by-layer deposition from the bottom, by overcoming the limits imposed by gravitational force. By taking advantage of a hydrogel bath, serving as a sacrificial

  6. Embedded data representations

    DEFF Research Database (Denmark)

    Willett, Wesley; Jansen, Yvonne; Dragicevic, Pierre

    2017-01-01

    We introduce embedded data representations, the use of visual and physical representations of data that are deeply integrated with the physical spaces, objects, and entities to which the data refers. Technologies like lightweight wireless displays, mixed reality hardware, and autonomous vehicles...

  7. Polarizable Density Embedding

    DEFF Research Database (Denmark)

    Reinholdt, Peter; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard

    2017-01-01

    We analyze the performance of the polarizable density embedding (PDE) model-a new multiscale computational approach designed for prediction and rationalization of general molecular properties of large and complex systems. We showcase how the PDE model very effectively handles the use of large...

  8. Embedded enzymes catalyse capture

    Science.gov (United States)

    Kentish, Sandra

    2018-05-01

    Membrane technologies for carbon capture can offer economic and environmental advantages over conventional amine-based absorption, but can suffer from limited gas flux and selectivity to CO2. Now, a membrane based on enzymes embedded in hydrophilic pores is shown to exhibit combined flux and selectivity that challenges the state of the art.

  9. Two level undercut-profile substrate for filamentary YBa2Cu3O7 coated conductors

    DEFF Research Database (Denmark)

    Wulff, Anders Christian; Solovyov, M.; Gömöry, Fedor

    2015-01-01

    A novel substrate design is presented for scalable industrial production of filamentary coated conductors (CCs). The new substrate, called ‘two level undercut-profile substrate (2LUPS)’, has two levels of plateaus connected by walls with an undercut profile. The undercuts are made to produce...... a shading effect during subsequent deposition of layers, thereby creating gaps in the superconducting layer deposited on the curved walls between the two levels. It is demonstrated that such 2LUPS-based CCs can be produced in a large-scale production system using standard deposition processes...

  10. Inverse problem for a two-level medium with an inhomgeneously broadened transition in the field of a periodic wave

    International Nuclear Information System (INIS)

    Zabolotskii, A.A.

    1995-01-01

    The inverse problem is considered for a spectral problem, which is formally equivalent to a system of Bloch equations for an inhomogeneously broadened transition interacting with the electric field. Two cases are considered to demonstrate that, for any given frequency interval, one can determine the pulse of the shape which corresponds to the interaction with only this frequency interval. In the general case, the pulse shape is described by a nonlinear periodic wave. The first example is the resonance interaction of light with a gas of two-level atoms. The second example is interaction of a linearly polarized light with the molecular J-J transition, where J much-gt 1. In the latter case, the role of inhomogeneous broadening belongs to the frequency shift induced by the applied magnetic field. 10 refs

  11. Oxygen Atom Transfer Using an Iron(IV)-Oxo Embedded in a Tetracyclic N-Heterocyclic Carbene System: How Does the Reactivity Compare to Cytochrome P450 Compound I?

    Science.gov (United States)

    Cantú Reinhard, Fabián G; de Visser, Sam P

    2017-02-24

    N-Heterocyclic carbenes (NHC) are commonly featured as ligands in transition metal catalysis. Recently, a cyclic system containing four NHC groups with a central iron atom was synthesized and its iron(IV)-oxo species, [Fe IV (O)(cNHC 4 )] 2+ , was characterized. This tetracyclic NHC ligand system may give the iron(IV)-oxo species unique catalytic properties as compared to traditional non-heme and heme iron ligand systems. Therefore, we performed a computational study on the structure and reactivity of the [Fe IV (O)(cNHC 4 )] 2+ complex in substrate hydroxylation and epoxidation reactions. The reactivity patterns are compared with cytochrome P450 Compound I and non-heme iron(IV)-oxo models and it is shown that the [Fe IV (O)(cNHC 4 )] 2+ system is an effective oxidant with oxidative power analogous to P450 Compound I. Unfortunately, in polar solvents, a solvent molecule will bind to the sixth ligand position and decrease the catalytic activity of the oxidant. A molecular orbital and valence bond analysis provides insight into the origin of the reactivity differences and makes predictions of how to further exploit these systems in chemical catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Charge trapping characteristics of Au nanocrystals embedded in remote plasma atomic layer-deposited Al2O3 film as the tunnel and blocking oxides for nonvolatile memory applications

    International Nuclear Information System (INIS)

    Lee, Jaesang; Kim, Hyungchul; Park, Taeyong; Ko, Youngbin; Ryu, Jaehun; Jeon, Heeyoung; Park, Jingyu; Jeon, Hyeongtag

    2012-01-01

    Remote plasma atomic layer deposited (RPALD) Al 2 O 3 films were investigated to apply as tunnel and blocking layers in the metal-oxide-semiconductor capacitor memory utilizing Au nanocrystals (NCs) for nonvolatile memory applications. The interface stability of an Al 2 O 3 film deposited by RPALD was studied to observe the effects of remote plasma on the interface. The interface formed during RPALD process has high oxidation states such as Si +3 and Si +4 , indicating that RPALD process can grow more stable interface which has a small amount of fixed oxide trap charge. The significant memory characteristics were also observed in this memory device through the electrical measurement. The memory device exhibited a relatively large memory window of 5.6 V under a 10/-10 V program/erase voltage and also showed the relatively fast programming/erasing speed and a competitive retention characteristic after 10 4 s. These results indicate that Al 2 O 3 films deposited via RPALD can be applied as the tunnel and blocking oxides for next-generation flash memory devices.

  13. The entanglement evolution between two entangled atoms

    Indian Academy of Sciences (India)

    Entanglement is an important resource for quantum information processing. [1–3] and also one of the most important nonclassical properties in quantum theory. ... consideration, which consists of two entangled two-level atoms A and B with ...

  14. Two levels ARIMAX and regression models for forecasting time series data with calendar variation effects

    Science.gov (United States)

    Suhartono, Lee, Muhammad Hisyam; Prastyo, Dedy Dwi

    2015-12-01

    The aim of this research is to develop a calendar variation model for forecasting retail sales data with the Eid ul-Fitr effect. The proposed model is based on two methods, namely two levels ARIMAX and regression methods. Two levels ARIMAX and regression models are built by using ARIMAX for the first level and regression for the second level. Monthly men's jeans and women's trousers sales in a retail company for the period January 2002 to September 2009 are used as case study. In general, two levels of calendar variation model yields two models, namely the first model to reconstruct the sales pattern that already occurred, and the second model to forecast the effect of increasing sales due to Eid ul-Fitr that affected sales at the same and the previous months. The results show that the proposed two level calendar variation model based on ARIMAX and regression methods yields better forecast compared to the seasonal ARIMA model and Neural Networks.

  15. Efficiency analysis on a two-level three-phase quasi-soft-switching inverter

    DEFF Research Database (Denmark)

    Geng, Pan; Wu, Weimin; Huang, Min

    2013-01-01

    When designing an inverter, an engineer often needs to select and predict the efficiency beforehand. For the standard inverters, plenty of researches are analyzing the power losses and also many software tools are being used for efficiency calculation. In this paper, the efficiency calculation...... for non-conventional inverters with special shoot-through state is introduced and illustrated through the analysis on a special two-level three-phase quasi-soft-switching inverter. Efficiency comparison between the classical two-stage two-level three-phase inverter and the two-level three-phase quasi......-soft-switching inverter is carried out. A 10 kW/380 V prototype is constructed to verify the analysis. The experimental results show that the efficiency of the new inverter is higher than that of the traditional two-stage two- level three-phase inverter....

  16. Excitation transfer in two two-level systems coupled to an oscillator

    International Nuclear Information System (INIS)

    Hagelstein, P L; Chaudhary, I U

    2008-01-01

    We consider a generalization of the spin-boson model in which two different two-level systems are coupled to an oscillator, under conditions where the oscillator energy is much less than the two-level system energies, and where the oscillator is highly excited. We find that the two-level system transition energy is shifted, producing a Bloch-Siegert shift in each two-level system similar to what would be obtained if the other were absent. At resonances associated with energy exchange between a two-level system and the oscillator, the level splitting is about the same as would be obtained in the spin-boson model at a Bloch-Siegert resonance. However, there occur resonances associated with the transfer of excitation between one two-level system and the other, an effect not present in the spin-boson model. We use a unitary transformation leading to a rotated system in which terms responsible for the shift and splittings can be identified. The level splittings at the anticrossings associated with both energy exchange and excitation transfer resonances are accounted for with simple two-state models and degenerate perturbation theory using operators that appear in the rotated Hamiltonian

  17. Embedding in thermosetting resins

    International Nuclear Information System (INIS)

    Buzonniere, A. de

    1985-01-01

    Medium activity waste coming either from nuclear power plants in operation such as evaporator concentrates, spent resins, filter cartridges or the dismantling of installations are embedded in order to obtain a product suitable for long term disposal. Embedding in thermosetting resins (polyester or epoxy) is one among currently used techniques; it is being developed by the CEA (Commissariat a l'Energie Atomique) and Technicatome (subsidiary of CEA and EDF). The process is easy to operate and yields excellent results particularly as far as volume reduction and radioelement containment (cesium particularly) are concerned. The process has already been in operation in four stationary plants for several years. Extension of the process to mobile units has been completed by Technicatome in collaboration with the CEA [fr

  18. Effects of phase memory in spectroscopy of test field of two level system at small frequencies of collisions

    International Nuclear Information System (INIS)

    Parkhomenko, A.I.; Shalagin, A.M.

    2006-01-01

    One studied theoretically spectrum of absorption (intensification) of a weak sounding field by two-level atoms moving in a strong resonance laser field and colliding with buffer gas atoms. The analysis was performed for the case of small frequencies of collisions in contrast to the Doppler width of absorption line (gas low pressure) with regard to the arbitrary variation of a radiation induced dipole moment phase at elastic collisions of gas particles. The effects of phase memory are found to result in very strong quantitative and qualitative transformation of a test field spectrum even in case of infrequent collisions when the well-known Dike mechanism of manifestation of phase memory effects (elimination of the Doppler widening due to limitation of spatial motion of particles by collisions) does not work. Strong influence of phase memory effects on spectral resonances at gas low pressure results from the fact that phase retaining collisions change dependence on velocity of the partial index of refraction n(v) (index of refraction for particles moving with v velocity) [ru

  19. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.

    1999-01-01

    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  20. Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks

    Directory of Open Access Journals (Sweden)

    Fapojuwo Abraham O

    2007-01-01

    Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.

  1. Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks

    Directory of Open Access Journals (Sweden)

    Abraham O. Fapojuwo

    2007-11-01

    Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.

  2. Quantum Dots Embedded in Graphene Nanoribbons by Chemical Substitution

    DEFF Research Database (Denmark)

    Carbonell-Sanroma, Eduard; Brandimarte, Pedro; Balog, Richard

    2017-01-01

    Bottom-up chemical reactions of selected molecular precursors on a gold surface can produce high quality graphene nanoribbons (GNRs). Here, we report on the formation of quantum dots embedded in an armchair GNR by substitutional inclusion of pairs of boron atoms into the GNR backbone. The boron...

  3. Embedded software verification and debugging

    CERN Document Server

    Winterholer, Markus

    2017-01-01

    This book provides comprehensive coverage of verification and debugging techniques for embedded software, which is frequently used in safety critical applications (e.g., automotive), where failures are unacceptable. Since the verification of complex systems needs to encompass the verification of both hardware and embedded software modules, this book focuses on verification and debugging approaches for embedded software with hardware dependencies. Coverage includes the entire flow of design, verification and debugging of embedded software and all key approaches to debugging, dynamic, static, and hybrid verification. This book discusses the current, industrial embedded software verification flow, as well as emerging trends with focus on formal and hybrid verification and debugging approaches. Includes in a single source the entire flow of design, verification and debugging of embedded software; Addresses the main techniques that are currently being used in the industry for assuring the quality of embedded softw...

  4. Solutions of the two-level problem in terms of biconfluent Heun functions

    Energy Technology Data Exchange (ETDEWEB)

    Ishkhanyan, Artur [Engineering Center of Armenian National Academy of Sciences, Ashtarak (Armenia)]. E-mail: artur@ec.sci.am; Suominen, Kalle-Antti [Helsinki Institute of Physics, Helsinki (Finland); Department of Applied Physics, University of Turku, Turku (Finland)

    2001-08-17

    Five four-parametric classes of quantum mechanical two-level models permitting solutions in terms of the biconfluent Heun function are derived. Three of these classes are generalizations of the well known classes of Landau-Zener, Nikitin and Crothers. It is shown that two other classes describe super- and sublinear and essentially nonlinear level crossings, as well as processes with three crossing points. In particular, these classes include two-level models where the field amplitude is constant and the detuning varies as {delta}{sub 0}t+{delta}{sub 2}t{sup 3} or {approx}t{sup 1/3}. For the essentially nonlinear cubic-crossing model, {delta}{sub t}{approx}{delta}{sub 2}t{sup 3}, the general solution of the two-level problem is shown to be expressed as series of confluent hypergeometric functions. (author)

  5. Two-Level Solutions to Exponentially Complex Problems in Glass Science

    DEFF Research Database (Denmark)

    Mauro, John C.; Smedskjær, Morten Mattrup

    Glass poses an especially challenging problem for physicists. The key to making progress in theoretical glass science is to extract the key physics governing properties of practical interest. In this spirit, we discuss several two-level solutions to exponentially complex problems in glass science....... Topological constraint theory, originally developed by J.C. Phillips, is based on a two-level description of rigid and floppy modes in a glass network and can be used to derive quantitatively accurate and analytically solvable models for a variety of macroscopic properties. The temperature dependence...... that captures both primary and secondary relaxation modes. Such a model also offers the ability to calculate the distinguishability of particles during glass transition and relaxation processes. Two-level models can also be used to capture the distribution of various network-forming species in mixed...

  6. Crossing rule for a PT-symmetric two-level time-periodic system

    International Nuclear Information System (INIS)

    Moiseyev, Nimrod

    2011-01-01

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  7. Atom-by-atom assembly

    International Nuclear Information System (INIS)

    Hla, Saw Wai

    2014-01-01

    Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed. (review article)

  8. Kir2.1 channels set two levels of resting membrane potential with inward rectification.

    Science.gov (United States)

    Chen, Kuihao; Zuo, Dongchuan; Liu, Zheng; Chen, Haijun

    2018-04-01

    Strong inward rectifier K + channels (Kir2.1) mediate background K + currents primarily responsible for maintenance of resting membrane potential. Multiple types of cells exhibit two levels of resting membrane potential. Kir2.1 and K2P1 currents counterbalance, partially accounting for the phenomenon of human cardiomyocytes in subphysiological extracellular K + concentrations or pathological hypokalemic conditions. The mechanism of how Kir2.1 channels contribute to the two levels of resting membrane potential in different types of cells is not well understood. Here we test the hypothesis that Kir2.1 channels set two levels of resting membrane potential with inward rectification. Under hypokalemic conditions, Kir2.1 currents counterbalance HCN2 or HCN4 cation currents in CHO cells that heterologously express both channels, generating N-shaped current-voltage relationships that cross the voltage axis three times and reconstituting two levels of resting membrane potential. Blockade of HCN channels eliminated the phenomenon in K2P1-deficient Kir2.1-expressing human cardiomyocytes derived from induced pluripotent stem cells or CHO cells expressing both Kir2.1 and HCN2 channels. Weakly inward rectifier Kir4.1 or inward rectification-deficient Kir2.1•E224G mutant channels do not set such two levels of resting membrane potential when co-expressed with HCN2 channels in CHO cells or when overexpressed in human cardiomyocytes derived from induced pluripotent stem cells. These findings demonstrate a common mechanism that Kir2.1 channels set two levels of resting membrane potential with inward rectification by balancing inward currents through different cation channels such as hyperpolarization-activated HCN channels or hypokalemia-induced K2P1 leak channels.

  9. Unsteady Flame Embedding

    KAUST Repository

    El-Asrag, Hossam A.

    2011-01-01

    Direct simulation of all the length and time scales relevant to practical combustion processes is computationally prohibitive. When combustion processes are driven by reaction and transport phenomena occurring at the unresolved scales of a numerical simulation, one must introduce a dynamic subgrid model that accounts for the multiscale nature of the problem using information available on a resolvable grid. Here, we discuss a model that captures unsteady flow-flame interactions- including extinction, re-ignition, and history effects-via embedded simulations at the subgrid level. The model efficiently accounts for subgrid flame structure and incorporates detailed chemistry and transport, allowing more accurate prediction of the stretch effect and the heat release. In this chapter we first review the work done in the past thirty years to develop the flame embedding concept. Next we present a formulation for the same concept that is compatible with Large Eddy Simulation in the flamelet regimes. The unsteady flame embedding approach (UFE) treats the flame as an ensemble of locally one-dimensional flames, similar to the flamelet approach. However, a set of elemental one-dimensional flames is used to describe the turbulent flame structure directly at the subgrid level. The calculations employ a one-dimensional unsteady flame model that incorporates unsteady strain rate, curvature, and mixture boundary conditions imposed by the resolved scales. The model is used for closure of the subgrid terms in the context of large eddy simulation. Direct numerical simulation (DNS) data from a flame-vortex interaction problem is used for comparison. © Springer Science+Business Media B.V. 2011.

  10. A Two-Level Cache for Distributed Information Retrieval in Search Engines

    Directory of Open Access Journals (Sweden)

    Weizhe Zhang

    2013-01-01

    Full Text Available To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users’ logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  11. A two-level cache for distributed information retrieval in search engines.

    Science.gov (United States)

    Zhang, Weizhe; He, Hui; Ye, Jianwei

    2013-01-01

    To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users' logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  12. Embedded microcontroller interfacing

    CERN Document Server

    Gupta, Gourab Sen

    2010-01-01

    Mixed-Signal Embedded Microcontrollers are commonly used in integrating analog components needed to control non-digital electronic systems. They are used in automatically controlled devices and products, such as automobile engine control systems, wireless remote controllers, office machines, home appliances, power tools, and toys. Microcontrollers make it economical to digitally control even more devices and processes by reducing the size and cost, compared to a design that uses a separate microprocessor, memory, and input/output devices. In many undergraduate and post-graduate courses, teachi

  13. Efficient Atomic One-Qubit Phase Gate Realized by a Cavity QED and Identical Atoms System

    International Nuclear Information System (INIS)

    He Yong; Jiang Nianquan

    2010-01-01

    We present a scheme to implement a one-qubit phase gate with a two-level atom crossing an optical cavity in which some identical atoms are trapped. One can conveniently acquire an arbitrary phase shift of the gate by properly choosing the number of atoms trapped in the cavity and the velocity of the atom crossing the cavity. The present scheme provides a very simple and efficient way for implementing one-qubit phase gate. (general)

  14. Embedded Multimaterial Extrusion Bioprinting.

    Science.gov (United States)

    Rocca, Marco; Fragasso, Alessio; Liu, Wanjun; Heinrich, Marcel A; Zhang, Yu Shrike

    2018-04-01

    Embedded extrusion bioprinting allows for the generation of complex structures that otherwise cannot be achieved with conventional layer-by-layer deposition from the bottom, by overcoming the limits imposed by gravitational force. By taking advantage of a hydrogel bath, serving as a sacrificial printing environment, it is feasible to extrude a bioink in freeform until the entire structure is deposited and crosslinked. The bioprinted structure can be subsequently released from the supporting hydrogel and used for further applications. Combining this advanced three-dimensional (3D) bioprinting technique with a multimaterial extrusion printhead setup enables the fabrication of complex volumetric structures built from multiple bioinks. The work described in this paper focuses on the optimization of the experimental setup and proposes a workflow to automate the bioprinting process, resulting in a fast and efficient conversion of a virtual 3D model into a physical, extruded structure in freeform using the multimaterial embedded bioprinting system. It is anticipated that further development of this technology will likely lead to widespread applications in areas such as tissue engineering, pharmaceutical testing, and organs-on-chips.

  15. Learning optimal embedded cascades.

    Science.gov (United States)

    Saberian, Mohammad Javad; Vasconcelos, Nuno

    2012-10-01

    The problem of automatic and optimal design of embedded object detector cascades is considered. Two main challenges are identified: optimization of the cascade configuration and optimization of individual cascade stages, so as to achieve the best tradeoff between classification accuracy and speed, under a detection rate constraint. Two novel boosting algorithms are proposed to address these problems. The first, RCBoost, formulates boosting as a constrained optimization problem which is solved with a barrier penalty method. The constraint is the target detection rate, which is met at all iterations of the boosting process. This enables the design of embedded cascades of known configuration without extensive cross validation or heuristics. The second, ECBoost, searches over cascade configurations to achieve the optimal tradeoff between classification risk and speed. The two algorithms are combined into an overall boosting procedure, RCECBoost, which optimizes both the cascade configuration and its stages under a detection rate constraint, in a fully automated manner. Extensive experiments in face, car, pedestrian, and panda detection show that the resulting detectors achieve an accuracy versus speed tradeoff superior to those of previous methods.

  16. Experimental Research into the Two-Level Cylindrical Cyclone with a Different Number of Channels

    Directory of Open Access Journals (Sweden)

    Egidijus Baliukas

    2014-10-01

    Full Text Available The multichannel two-level cyclone has been designed for separating solid particles from airflow and built at the Laboratory of Environmental Protection Technologies of Vilnius Gediminas Technical University. The conducted research is aimed at determining air flow distribution at two levels and channels of the multichannel cyclone. The multifunctional meter Testo-400 and the dynamic Pitot tube have been used form easuring air flow rates in the channels. The obtained results show that the equal volume of air gets into two levels installed inside the cyclone, and rates are distributed equally in the channels of these levels. The maximum air flow rate is recorded in the first channel and occurs when half-rings are set in such positions so that 75% of air flow returns to the previous channel. The biggest aerodynamic resistance is 1660 Pa and has been recorded in the cyclone having eight channels under air flow distribution ratio 75/25. The highest air purification efficiency has been observed in the two-level six-channel cyclone under air flow distribution ratio 75/25. The effectiveness of separating granite particles is 92.1% and that of wood particles – 91.1 when the particles are up to 20 μm in diameter.

  17. Resonant retuning of Rabi oscillations in a two-level system

    International Nuclear Information System (INIS)

    Leonov, A.V.; Feranchuk, I.D.

    2009-01-01

    The evolution of a two-level system in a single-mode quantum field is considered beyond the rotating wave approximation. The existence of quasi-degenerate energy levels is shown to influence the essential characteristics of temporal and amplitude Rabi oscillations of the system in a resonant manner. (authors)

  18. An Owen-type value for games with two-level communication structures

    NARCIS (Netherlands)

    van den Brink, René; Khmelnitskaya, Anna Borisovna; van der Laan, Gerard

    We introduce an Owen-type value for games with two-level communication structure, which is a structure where the players are partitioned into a coalition structure such that there exists restricted communication between as well as within the a priori unions of the coalition structure. Both types of

  19. Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, M.

    2013-01-01

    The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

  20. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2012-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  1. Excitation of graphene plasmons as an analogy with the two-level system

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiahui [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Lv, Bo, E-mail: lb19840313@126.com [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Li, Rujiang [College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027 (China); Ma, Ruyu; Chen, Wan; Meng, Fanyi [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China)

    2016-02-15

    The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

  2. Analysis of Two-Level Support Systems with Time-Dependent Overflow - A Banking Application

    DEFF Research Database (Denmark)

    Barth, Wolfgang; Manitz, Michael; Stolletz, Raik

    2010-01-01

    In this paper, we analyze the performance of call centers of financial service providers with two levels of support and a time-dependent overflow mechanism. Waiting calls from the front-office queue flow over to the back office if a waiting-time limit is reached and at least one back-office agent...

  3. Excitation of graphene plasmons as an analogy with the two-level system

    International Nuclear Information System (INIS)

    Fu, Jiahui; Lv, Bo; Li, Rujiang; Ma, Ruyu; Chen, Wan; Meng, Fanyi

    2016-01-01

    The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

  4. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2013-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  5. Efficient two-level preconditionined conjugate gradient method on the GPU

    NARCIS (Netherlands)

    Gupta, R.; Van Gijzen, M.B.; Vuik, K.

    2011-01-01

    We present an implementation of Two-Level Preconditioned Conjugate Gradient Method for the GPU. We investigate a Truncated Neumann Series based preconditioner in combination with deflation and compare it with Block Incomplete Cholesky schemes. This combination exhibits fine-grain parallelism and

  6. A spatial scan statistic for nonisotropic two-level risk cluster.

    Science.gov (United States)

    Li, Xiao-Zhou; Wang, Jin-Feng; Yang, Wei-Zhong; Li, Zhong-Jie; Lai, Sheng-Jie

    2012-01-30

    Spatial scan statistic methods are commonly used for geographical disease surveillance and cluster detection. The standard spatial scan statistic does not model any variability in the underlying risks of subregions belonging to a detected cluster. For a multilevel risk cluster, the isotonic spatial scan statistic could model a centralized high-risk kernel in the cluster. Because variations in disease risks are anisotropic owing to different social, economical, or transport factors, the real high-risk kernel will not necessarily take the central place in a whole cluster area. We propose a spatial scan statistic for a nonisotropic two-level risk cluster, which could be used to detect a whole cluster and a noncentralized high-risk kernel within the cluster simultaneously. The performance of the three methods was evaluated through an intensive simulation study. Our proposed nonisotropic two-level method showed better power and geographical precision with two-level risk cluster scenarios, especially for a noncentralized high-risk kernel. Our proposed method is illustrated using the hand-foot-mouth disease data in Pingdu City, Shandong, China in May 2009, compared with two other methods. In this practical study, the nonisotropic two-level method is the only way to precisely detect a high-risk area in a detected whole cluster. Copyright © 2011 John Wiley & Sons, Ltd.

  7. Two-Level Designs to Estimate All Main Effects and Two-Factor Interactions

    NARCIS (Netherlands)

    Eendebak, P.T.; Schoen, E.D.

    2017-01-01

    We study the design of two-level experiments with N runs and n factors large enough to estimate the interaction model, which contains all the main effects and all the two-factor interactions. Yet, an effect hierarchy assumption suggests that main effect estimation should be given more prominence

  8. Exact Solution of the Two-Level System and the Einstein Solid in the Microcanonical Formalism

    Science.gov (United States)

    Bertoldi, Dalia S.; Bringa, Eduardo M.; Miranda, E. N.

    2011-01-01

    The two-level system and the Einstein model of a crystalline solid are taught in every course of statistical mechanics and they are solved in the microcanonical formalism because the number of accessible microstates can be easily evaluated. However, their solutions are usually presented using the Stirling approximation to deal with factorials. In…

  9. CO oxidation catalyzed by Pt-embedded graphene: A first-principles investigation

    KAUST Repository

    Liu, Xin; Sui, Yanhui; Duan, Ting; Meng, Changong; Han, Yu

    2014-01-01

    We addressed the potential catalytic role of Pt-embedded graphene in CO oxidation by first-principles-based calculations. We showed that the combination of highly reactive Pt atoms and defects over graphene makes the Pt-embedded graphene a superior mono-dispersed atomic catalyst for CO oxidation. The binding energy of a single Pt atom onto monovacancy defects is up to -7.10 eV, which not only ensures the high stability of the embedded Pt atom, but also vigorously excludes the possibility of diffusion and aggregation of embedded Pt atoms. This strong interfacial interaction also tunes the energy level of Pt-d states for the activation of O2, and promotes the formation and dissociation of the peroxide-like intermediate. The catalytic cycle of CO oxidation is initiated through the Langmuir-Hinshelwood mechanism, with the formation of a peroxide-like intermediate by the coadsorbed CO and O2, by the dissociation of which the CO2 molecule and an adsorbed O atom are formed. Then, another gaseous CO will react with the remnant O atom and make the embedded Pt atom available for the subsequent reaction. The calculated energy barriers for the formation and dissociation of the peroxide-like intermediate are as low as 0.33 and 0.15 eV, respectively, while that for the regeneration of the embedded Pt atom is 0.46 eV, indicating the potential high catalytic performance of Pt-embedded graphene for low temperature CO oxidation.

  10. Beams made of twisted atoms: A theoretical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hayrapetyan, Armen [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); Matula, Oliver [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Surzhykov, Andrey [Helmholtz-Institut Jena, 07743 Jena (Germany); Fritzsche, Stephan [Helmholtz-Institut Jena, 07743 Jena (Germany); Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universitaet Jena, 07743 Jena (Germany)

    2014-07-01

    We have analyzed Bessel beams of two-level atoms that are driven by a linearly polarized laser light. Based on the Schroedinger equation for two-level systems, we first determine the states of two-level atoms in a plane-wave field by taking into account propagation directions both of the atom and the field. For such laser-driven two-level atoms, we construct Bessel beams by going beyond the typical paraxial approximation. In particular, we show that the probability density of these atomic beams exhibits a non-trivial, Bessel-squared-type behavior. The profile of such twisted atoms is affected by atom and laser parameters, such as the nuclear charge, atom velocity, laser frequency, and propagation geometry of the atom and laser beams. Moreover, we spatially and temporally characterize the beam of hydrogen and selected (neutral) alkali-metal atoms that carry non-zero orbital angular momentum (OAM). The proposed spatiotemporal Bessel states (i) are able to describe twisted states of any two-level system which is driven by the radiation field and (ii) have potential applications in atomic and nuclear processes as well as in quantum communication.

  11. Spatially Embedded Inequality

    DEFF Research Database (Denmark)

    Holck, Lotte

    2016-01-01

    /methodology/approach: – The (re)production of inequality is explored by linking research on organizational space with HRM diversity management. Data from an ethnographic study undertaken in a Danish municipal center illustrates how a substructure of inequality is spatially upheld alongside a formal diversity policy. Archer...... and ethnification of job categories. However, the same spatial structures allows for a variety of opposition and conciliation strategies among minority employees, even though the latter tend to prevail in a reproduction rather than a transformation of the organizational opportunity structures. Research limitations...... the more subtle, spatially embedded forms of inequality. Originality/value: – Theoretical and empirical connections between research on organizational space and HRM diversity management have thus far not been systematically studied. This combination might advance knowledge on the persistence of micro...

  12. Embedded sensor systems

    CERN Document Server

    Agrawal, Dharma Prakash

    2017-01-01

    This inspiring textbook provides an introduction to wireless technologies for sensors, explores potential use of sensors for numerous applications, and utilizes probability theory and mathematical methods as a means of embedding sensors in system design. It discusses the need for synchronization and underlying limitations, inter-relation between given coverage and connectivity to number of sensors needed, and the use of geometrical distance to determine location of the base station for data collection and explore use of anchor nodes for relative position determination of sensors. The book explores energy conservation, communication using TCP, the need for clustering and data aggregation, and residual energy determination and energy harvesting. It covers key topics of sensor communication like mobile base stations and relay nodes, delay-tolerant sensor networks, and remote sensing and possible applications. The book defines routing methods and do performance evaluation for random and regular sensor topology an...

  13. Communicating embedded systems networks applications

    CERN Document Server

    Krief, Francine

    2013-01-01

    Embedded systems become more and more complex and require having some knowledge in various disciplines such as electronics, data processing, telecommunications and networks. Without detailing all the aspects related to the design of embedded systems, this book, which was written by specialists in electronics, data processing and telecommunications and networks, gives an interesting point of view of communication techniques and problems in embedded systems. This choice is easily justified by the fact that embedded systems are today massively communicating and that telecommunications and network

  14. Advances in embedded computer vision

    CERN Document Server

    Kisacanin, Branislav

    2014-01-01

    This illuminating collection offers a fresh look at the very latest advances in the field of embedded computer vision. Emerging areas covered by this comprehensive text/reference include the embedded realization of 3D vision technologies for a variety of applications, such as stereo cameras on mobile devices. Recent trends towards the development of small unmanned aerial vehicles (UAVs) with embedded image and video processing algorithms are also examined. The authoritative insights range from historical perspectives to future developments, reviewing embedded implementation, tools, technolog

  15. Embedded Systems Design with FPGAs

    CERN Document Server

    Pnevmatikatos, Dionisios; Sklavos, Nicolas

    2013-01-01

    This book presents methodologies for modern applications of embedded systems design, using field programmable gate array (FPGA) devices.  Coverage includes state-of-the-art research from academia and industry on a wide range of topics, including advanced electronic design automation (EDA), novel system architectures, embedded processors, arithmetic, dynamic reconfiguration and applications. Describes a variety of methodologies for modern embedded systems design;  Implements methodologies presented on FPGAs; Covers a wide variety of applications for reconfigurable embedded systems, including Bioinformatics, Communications and networking, Application acceleration, Medical solutions, Experiments for high energy physics, Astronomy, Aerospace, Biologically inspired systems and Computational fluid dynamics (CFD).

  16. Embedding Complementarity in HCI Methods

    DEFF Research Database (Denmark)

    Nielsen, Janni; Yssing, Carsten; Tweddell Levinsen, Karin

    2007-01-01

    Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded in the tec......Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded...

  17. Atomic polarizabilities

    International Nuclear Information System (INIS)

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-01

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed

  18. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  19. Atomic physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  20. Time-dependent potential-functional embedding theory

    International Nuclear Information System (INIS)

    Huang, Chen; Libisch, Florian; Peng, Qing; Carter, Emily A.

    2014-01-01

    We introduce a time-dependent potential-functional embedding theory (TD-PFET), in which atoms are grouped into subsystems. In TD-PFET, subsystems can be propagated by different suitable time-dependent quantum mechanical methods and their interactions can be treated in a seamless, first-principles manner. TD-PFET is formulated based on the time-dependent quantum mechanics variational principle. The action of the total quantum system is written as a functional of the time-dependent embedding potential, i.e., a potential-functional formulation. By exploiting the Runge-Gross theorem, we prove the uniqueness of the time-dependent embedding potential under the constraint that all subsystems share a common embedding potential. We derive the integral equation that such an embedding potential needs to satisfy. As proof-of-principle, we demonstrate TD-PFET for a Na 4 cluster, in which each Na atom is treated as one subsystem and propagated by time-dependent Kohn-Sham density functional theory (TDDFT) using the adiabatic local density approximation (ALDA). Our results agree well with a direct TDDFT calculation on the whole Na 4 cluster using ALDA. We envision that TD-PFET will ultimately be useful for studying ultrafast quantum dynamics in condensed matter, where key regions are solved by highly accurate time-dependent quantum mechanics methods, and unimportant regions are solved by faster, less accurate methods

  1. Atomic physics

    International Nuclear Information System (INIS)

    Armbruster, P.; Beyer, H.; Bosch, F.; Dohmann, H.D.; Kozhuharov, C.; Liesen, D.; Mann, R.; Mokler, P.H.

    1984-01-01

    The heavy ion accelerator UNILAC is well suited to experiments in the field of atomic physics because, with the aid of high-energy heavy ions atoms can be produced in exotic states - that is, heavy atoms with only a few electrons. Also, in close collisions of heavy ions (atomic number Z 1 ) and heavy target atoms (Z 2 ) short-lived quasi-atomic 'superheavy' systems will be formed - huge 'atoms', where the inner electrons are bound in the field of the combined charge Z 1 + Z 2 , which exceeds by far the charge of the known elements (Z <= 109). Those exotic or transient superheavy atoms delivered from the heavy ion accelerator make it possible to study for the first time in a terrestrial laboratory exotic, but fundamental, processes, which occur only inside stars. Some of the basic research carried out with the UNILAC is discussed. This includes investigation of highly charged heavy atoms with the beam-foil method, the spectroscopy of highly charged slow-recoil ions, atomic collision studies with highly ionised, decelerated ions and investigations of super-heavy quasi-atoms. (U.K.)

  2. Embedding potentials for excited states of embedded species

    International Nuclear Information System (INIS)

    Wesolowski, Tomasz A.

    2014-01-01

    Frozen-Density-Embedding Theory (FDET) is a formalism to obtain the upper bound of the ground-state energy of the total system and the corresponding embedded wavefunction by means of Euler-Lagrange equations [T. A. Wesolowski, Phys. Rev. A 77(1), 012504 (2008)]. FDET provides the expression for the embedding potential as a functional of the electron density of the embedded species, electron density of the environment, and the field generated by other charges in the environment. Under certain conditions, FDET leads to the exact ground-state energy and density of the whole system. Following Perdew-Levy theorem on stationary states of the ground-state energy functional, the other-than-ground-state stationary states of the FDET energy functional correspond to excited states. In the present work, we analyze such use of other-than-ground-state embedded wavefunctions obtained in practical calculations, i.e., when the FDET embedding potential is approximated. Three computational approaches based on FDET, that assure self-consistent excitation energy and embedded wavefunction dealing with the issue of orthogonality of embedded wavefunctions for different states in a different manner, are proposed and discussed

  3. Ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Krüger, Peter; Hofferberth, S.; Haller, E.

    2005-01-01

    Miniaturized potentials near the surface of atom chips can be used as flexible and versatile tools for the manipulation of ultracold atoms on a microscale. The full scope of possibilities is only accessible if atom-surface distances can be reduced to microns. We discuss experiments in this regime...

  4. Analysis of stationary availability factor of two-level backbone computer networks with arbitrary topology

    Science.gov (United States)

    Rahman, P. A.

    2018-05-01

    This scientific paper deals with the two-level backbone computer networks with arbitrary topology. A specialized method, offered by the author for calculation of the stationary availability factor of the two-level backbone computer networks, based on the Markov reliability models for the set of the independent repairable elements with the given failure and repair rates and the methods of the discrete mathematics, is also discussed. A specialized algorithm, offered by the author for analysis of the network connectivity, taking into account different kinds of the network equipment failures, is also observed. Finally, this paper presents an example of calculation of the stationary availability factor for the backbone computer network with the given topology.

  5. Two-Level Iteration Penalty Methods for the Navier-Stokes Equations with Friction Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2013-01-01

    Full Text Available This paper presents two-level iteration penalty finite element methods to approximate the solution of the Navier-Stokes equations with friction boundary conditions. The basic idea is to solve the Navier-Stokes type variational inequality problem on a coarse mesh with mesh size H in combining with solving a Stokes, Oseen, or linearized Navier-Stokes type variational inequality problem for Stokes, Oseen, or Newton iteration on a fine mesh with mesh size h. The error estimate obtained in this paper shows that if H, h, and ε can be chosen appropriately, then these two-level iteration penalty methods are of the same convergence orders as the usual one-level iteration penalty method.

  6. Dynamics of quantum Fisher information in a two-level system coupled to multiple bosonic reservoirs

    Science.gov (United States)

    Wang, Guo-You; Guo, You-Neng; Zeng, Ke

    2015-11-01

    We consider the optimal parameter estimation for a two-level system coupled to multiple bosonic reservoirs. By using quantum Fisher information (QFI), we investigate the effect of the Markovian reservoirs’ number N on QFI in both weak and strong coupling regimes for a two-level system surrounded by N zero-temperature reservoirs of field modes initially in the vacua. The results show that the dynamics of QFI non-monotonically decays to zero with revival oscillations at some time in the weak coupling regime depending on the reservoirs’ parameters. Furthermore, we also present the relations between the QFI flow, the flows of energy and information, and the sign of the decay rate to gain insight into the physical processes characterizing the dynamics. Project supported by the Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2014B194) and the Scientific Research Foundation of Hunan Provincial Education Department, China (Grant No. 13C039).

  7. Minimax terminal approach problem in two-level hierarchical nonlinear discrete-time dynamical system

    Energy Technology Data Exchange (ETDEWEB)

    Shorikov, A. F., E-mail: afshorikov@mail.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002, Russia Institute of Mathematics and Mechanics, Ural Branch of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation)

    2015-11-30

    We consider a discrete–time dynamical system consisting of three controllable objects. The motions of all objects are given by the corresponding vector nonlinear or linear discrete–time recurrent vector relations, and control system for its has two levels: basic (first or I level) that is dominating and subordinate level (second or II level) and both have different criterions of functioning and united a priori by determined informational and control connections defined in advance. For the dynamical system in question, we propose a mathematical formalization in the form of solving a multistep problem of two-level hierarchical minimax program control over the terminal approach process with incomplete information and give a general scheme for its solving.

  8. A modified two-level three-phase quasi-soft-switching inverter

    DEFF Research Database (Denmark)

    Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede

    2014-01-01

    A traditional Voltage Source Inverter (VSI) has higher efficiency than a Current Voltage Source (CSI) due to the less conduction power loss. However, the reverse recovery of the free-wheeling diode limits the efficiency improvement for the silicon devices based hard-switching VSI. The traditional...... quasi-soft-switching inverter can alternate between VSI and CSI by using a proper control scheme and thereby reduce the power losses caused by the reverse recovery of the free-wheeling diode. Nevertheless, slightly extra conduction power loss of the auxiliary switch is also introduced. In order...... to reduce the extra conduction power loss and the voltage stress across the DC-link capacitor, a modified two-level three-phase quasi-soft-switching inverter is proposed by using a SiC MOSFET instead of an IGBT. The principle of the modified two-level three-phase quasi-soft-switching inverter is analyzed...

  9. Revisional Surgery for Hallux Valgus with Serial Osteotomies at Two Levels

    Directory of Open Access Journals (Sweden)

    Jason B. T. Lim

    2011-01-01

    Full Text Available The aetiology and form of hallux valgus (HV is varied with many corrective procedures described. We report a 39-year-old woman, previously treated with a Chevron osteotomy, who presented with recurrent right HV, metatarsus primus varus, and associated bunion. Osteotomies were performed at two levels as a revisional procedure. This report highlights (1 limitations of the Chevron osteotomy and (2 the revisional procedure of the two level osteotomies: (i proximal opening-wedge basal osteotomy and (ii distal short Scarf with medial closing wedges. If a Chevron osteotomy is used inappropriately, for example, in an attempt to correct too large a deformity, it may angulate laterally causing a malunion with an increased distal metatarsal articular angle. Secondly, it is feasible to correct this combined deformity using a combination of proximal opening-wedge and distal short Scarf osteotomies.

  10. Non-zero temperature two-mode squeezing for time-dependent two-level systems

    International Nuclear Information System (INIS)

    Aliaga, J.; Gruver, J.L.; Proto, A.N.; Cerdeira, H.A.

    1994-01-01

    A Maximum Entropy Principle density matrix method, valid for systems with temperature different from zero, is presented making it possible two-mode squeezed states in two-level systems with relevant operators and Hamiltonian connected with O(3,2). A method which allows one to relate the appearance of squeezing to the relevant operators, included in order to define the density matrix of the system is given. (author). 14 refs, 1 fig

  11. Urea metabolism in buffalo calves fed on rations containing two levels of crude protein

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.; Lal, M.; Varma, A.; Ranjhan, S.K.

    1974-01-01

    Urea entry rates into the body pools of Murrah Buffalo calves have been estimated using a single injection isotope dilution technique using 14 C-urea. The animals were fed two levels of crude proteins, namely, 13 percent lower and 19 percent higher than N.R.C. recommendations. Results show that the recycling of urea is significantly better in animals given low crude protein contents. (M.G.B.)

  12. Experiences of building a medical data acquisition system based on two-level modeling.

    Science.gov (United States)

    Li, Bei; Li, Jianbin; Lan, Xiaoyun; An, Ying; Gao, Wuqiang; Jiang, Yuqiao

    2018-04-01

    Compared to traditional software development strategies, the two-level modeling approach is more flexible and applicable to build an information system in the medical domain. However, the standards of two-level modeling such as openEHR appear complex to medical professionals. This study aims to investigate, implement, and improve the two-level modeling approach, and discusses the experience of building a unified data acquisition system for four affiliated university hospitals based on this approach. After the investigation, we simplified the approach of archetype modeling and developed a medical data acquisition system where medical experts can define the metadata for their own specialties by using a visual easy-to-use tool. The medical data acquisition system for multiple centers, clinical specialties, and diseases has been developed, and integrates the functions of metadata modeling, form design, and data acquisition. To date, 93,353 data items and 6,017 categories for 285 specific diseases have been created by medical experts, and over 25,000 patients' information has been collected. OpenEHR is an advanced two-level modeling method for medical data, but its idea to separate domain knowledge and technical concern is not easy to realize. Moreover, it is difficult to reach an agreement on archetype definition. Therefore, we adopted simpler metadata modeling, and employed What-You-See-Is-What-You-Get (WYSIWYG) tools to further improve the usability of the system. Compared with the archetype definition, our approach lowers the difficulty. Nevertheless, to build such a system, every participant should have some knowledge in both medicine and information technology domains, as these interdisciplinary talents are necessary. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Feedback controlled dephasing and population relaxation in a two-level system

    International Nuclear Information System (INIS)

    Wang Jin

    2009-01-01

    This Letter presents the maximum achievable stability and purity that can be obtained in a two-level system with both dephasing and population relaxation processes by using homodyne-mediated feedback control. An analytic formula giving the optimal amplitudes of the driving and feedback for the steady-state is also presented. Experimental examples are used to show the importance of controlling the dephasing process.

  14. FAST COMMUNICATION: A PDE Based Two Level Model of the Masking Property of the Human Ear

    OpenAIRE

    Xin, Jack; Qi, Yingyong

    2003-01-01

    Human ear has the masking property that certain audible sound becomes inaudible in the presence of another sound. Masking is quantified by the raised threshold from the absolute hearing threshold in quiet. It is of scientific and practical importance to compute masking thresholds. Empirical models on masking have applications in low bit rate digital music compression. A first principle based two level model is developed with partial differential equation (PDE) at the periphe...

  15. Effective Hamiltonians, two level systems, and generalized Maxwell-Bloch equations

    International Nuclear Information System (INIS)

    Sczaniecki, L.

    1981-02-01

    A new method is proposed involving a canonical transformation leading to the non-secular part of time-independent perturbation calculus. The method is used to derive expressions for effective Shen-Walls Hamiltonians which, taken in the two-level approximation and on the inclusion of non-Hamiltonian terms into the dynamics of the system, lead to generalized Maxwell-Bloch equations. The rotating wave approximation is written anew within the framework of our formalism. (author)

  16. Understanding of phase modulation in two-level systems through inverse scattering

    International Nuclear Information System (INIS)

    Hasenfeld, A.; Hammes, S.L.; Warren, W.S.

    1988-01-01

    Analytical and numerical calculations describe the effects of shaped radiation pulses on two-level systems in terms of quantum-mechanical scattering. Previous results obtained in the reduced case of amplitude modulation are extended to the general case of simultaneous amplitude and phase modulation. We show that an infinite family of phase- and amplitude-modulated pulses all generate rectangular inversion profiles. Experimental measurements also verify the theoretical analysis

  17. The simulation of the non-Markovian behaviour of a two-level system

    Science.gov (United States)

    Semina, I.; Petruccione, F.

    2016-05-01

    Non-Markovian relaxation dynamics of a two-level system is studied with the help of the non-linear stochastic Schrödinger equation with coloured Ornstein-Uhlenbeck noise. This stochastic Schrödinger equation is investigated numerically with an adapted Platen scheme. It is shown, that the memory effects have a significant impact to the dynamics of the system.

  18. Helium localization around the microscopic impurities embedded to liquid helium

    International Nuclear Information System (INIS)

    Gordon, E.B.; Shestakov, A.F.

    2000-01-01

    The structure and properties of the environment round the impurity atoms (Im) embedded in liquid helium are considered. It is shown that there are two qualitatively different types of structure of the He atom layer next to Im - attraction and repulsion structures. For the center attraction structure (strong Im-He interaction) the Im-He separation is longer than the equilibrium one for the pair Im-He potential, and the density and localization of He atoms are higher than in the bulk. It this case the He atom content in the layer, n, is almost independent of applied pressure. In the repulsion structure realized for alkaline metal atoms the Im-He separation is shorter than the equilibrium one and the density is lower than in the helium bulk. At T approx 1 K occupied are several states with different n and their energies differ only by approx 0.1 K, an increase in pressure resulting in a considerable reduction of n. The optical and EPR spectra of the atoms embedded to liquid and solid helium are interpreted on the basis of the analysis carried out. A simple model is proposed to evaluate the helium surroundings characteristics from the experimental pressure dependences of atomic line shifts in the absorption and emission spectra. The attraction structures in 3 He - 4 He mixtures are suggested to be highly enriched by 4 He atoms which the repulsion structures - by 3 He atoms. a possibility for existence of phase transitions in helium shells surrounding impurity atoms is considered

  19. Minimum time control of a pair of two-level quantum systems with opposite drifts

    International Nuclear Information System (INIS)

    Romano, Raffaele; D’Alessandro, Domenico

    2016-01-01

    In this paper we solve two equivalent time optimal control problems. On one hand, we design the control field to implement in minimum time the SWAP (or equivalent) operator on a two-level system, assuming that it interacts with an additional, uncontrollable, two-level system. On the other hand, we synthesize the SWAP operator simultaneously, in minimum time, on a pair of two-level systems subject to opposite drifts. We assume that it is possible to perform three independent control actions, and that the total control strength is bounded. These controls either affect the dynamics of the target system, under the first perspective, or, simultaneously, the dynamics of both systems, in the second view. We obtain our results by using techniques of geometric control theory on Lie groups. In particular, we apply the Pontryagin maximum principle, and provide a complete characterization of singular and nonsingular extremals. Our analysis shows that the problem can be formulated as the motion of a material point in a central force, a well known system in classical mechanics. Although we focus on obtaining the SWAP operator, many of the ideas and techniques developed in this work apply to the time optimal implementation of an arbitrary unitary operator. (paper)

  20. Two-Level Micro-to-Nanoscale Hierarchical TiO2 Nanolayers on Titanium Surface

    Directory of Open Access Journals (Sweden)

    Elena G. Zemtsova

    2016-12-01

    Full Text Available Joint replacement is being actively developed within modern orthopedics. One novel material providing fast implantation is bioactive coatings. The synthesis of targeted nanocoatings on metallic nanotitanium surface is reported in this paper. TiO2-based micro- and nanocoatings were produced by sol-gel synthesis using dip-coating technology with subsequent fast (shock drying in hot plate mode at 400 °C. As a result of shock drying, the two-level hierarchical TiO2 nanolayer on the nanotitanium was obtained. This two-level hierarchy includes nanorelief of porous xerogel and microrelief of the micron-sized “defect” network (a crack network. The thickness of TiO2 nanolayers was controlled by repeating dip-coating process the necessary number of times after the first layer deposition. The state of the MS3T3-E1 osteoblast cell line (young cells that form bone tissue on the two-level hierarchical surface has been studied. Particularly, adhesion character, adhesion time and morphology have been studied. The reported results may serve the starting point for the development of novel bioactive coatings for bone and teeth implants.

  1. Molecular interactions with ice: Molecular embedding, adsorption, detection, and release

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, K. D.; Langlois, Grant G.; Li, Wenxin; Sibener, S. J., E-mail: s-sibener@uchicago.edu [The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States); Killelea, Daniel R. [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Ave., Chicago, Illinois 60660 (United States)

    2014-11-14

    The interaction of atomic and molecular species with water and ice is of fundamental importance for chemistry. In a previous series of publications, we demonstrated that translational energy activates the embedding of Xe and Kr atoms in the near surface region of ice surfaces. In this paper, we show that inert molecular species may be absorbed in a similar fashion. We also revisit Xe embedding, and further probe the nature of the absorption into the selvedge. CF{sub 4} molecules with high translational energies (≥3 eV) were observed to embed in amorphous solid water. Just as with Xe, the initial adsorption rate is strongly activated by translational energy, but the CF{sub 4} embedding probability is much less than for Xe. In addition, a larger molecule, SF{sub 6}, did not embed at the same translational energies that both CF{sub 4} and Xe embedded. The embedding rate for a given energy thus goes in the order Xe > CF{sub 4} > SF{sub 6}. We do not have as much data for Kr, but it appears to have a rate that is between that of Xe and CF{sub 4}. Tentatively, this order suggests that for Xe and CF{sub 4}, which have similar van der Waals radii, the momentum is the key factor in determining whether the incident atom or molecule can penetrate deeply enough below the surface to embed. The more massive SF{sub 6} molecule also has a larger van der Waals radius, which appears to prevent it from stably embedding in the selvedge. We also determined that the maximum depth of embedding is less than the equivalent of four layers of hexagonal ice, while some of the atoms just below the ice surface can escape before ice desorption begins. These results show that energetic ballistic embedding in ice is a general phenomenon, and represents a significant new channel by which incident species can be trapped under conditions where they would otherwise not be bound stably as surface adsorbates. These findings have implications for many fields including environmental science, trace gas

  2. Rapid characterization of microscopic two-level systems using Landau-Zener transitions in a superconducting qubit

    International Nuclear Information System (INIS)

    Tan, Xinsheng; Yu, Haifeng; Yu, Yang; Han, Siyuan

    2015-01-01

    We demonstrate a fast method to detect microscopic two-level systems in a superconducting phase qubit. By monitoring the population leak after sweeping the qubit bias flux, we are able to measure the two-level systems that are coupled with the qubit. Compared with the traditional method that detects two-level systems by energy spectroscopy, our method is faster and more sensitive. This method supplies a useful tool to investigate two-level systems in solid-state qubits

  3. Modeling of Embedded Human Systems

    Science.gov (United States)

    2013-07-01

    ISAT study [7] for DARPA in 20051 concretized the notion of an embedded human, who is a necessary component of the system. The proposed work integrates...Technology, IEEE Transactions on, vol. 16, no. 2, pp. 229–244, March 2008. [7] C. J. Tomlin and S. S. Sastry, “Embedded humans,” tech. rep., DARPA ISAT

  4. To test photon statistics by atomic beam deflection

    International Nuclear Information System (INIS)

    Wang Yuzhu; Chen Yudan; Huang Weigang; Liu Liang

    1985-02-01

    There exists a simple relation between the photon statistics in resonance fluorescence and the statistics of the momentum transferred to an atom by a plane travelling wave [Cook, R.J., Opt. Commun., 35, 347(1980)]. Using an atomic beam deflection by light pressure, we have observed sub-Poissonian statistics in resonance fluorescence of two-level atoms. (author)

  5. Ubiquitous atom

    International Nuclear Information System (INIS)

    Spruch, G.M.; Spruch, L.

    1974-01-01

    The fundamentals of modern physics, including the basic physics and chemistry of the atom, elementary particles, cosmology, periodicity, and recent advances, are surveyed. The biology and chemistry of the life process is discussed to provide a background for considering the effects of atomic particles on living things. The uses of atomic power in space travel, merchant shipping, food preservation, desalination, and nuclear clocks are explored. (Pollut. Abstr.)

  6. Atomic physics

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 2 3 Po, 2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 2 3 Po level of helium-like krypton

  7. Renormalization of correlations in a quasiperiodically forced two-level system: quadratic irrationals

    International Nuclear Information System (INIS)

    Mestel, B D; Osbaldestin, A H

    2004-01-01

    Generalizing from the case of golden mean frequency to a wider class of quadratic irrationals, we extend our renormalization analysis of the self-similarity of correlation functions in a quasiperiodically forced two-level system. We give a description of all piecewise-constant periodic orbits of an additive functional recurrence generalizing that present in the golden mean case. We establish a criterion for periodic orbits to be globally bounded, and also calculate the asymptotic height of the main peaks in the correlation function

  8. Aspects of two-level systems under external time-dependent fields

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G.; Wreszinski, W.F. [Tomsk State University and Tomsk Institute of High Current Electronics (Russian Federation); Barata, J.C.A.; Gitman D.M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil)]. E-mails: jbarata@fma.if.usp.br; gitman@fma.if.usp.br

    2001-12-14

    The dynamics of two-level systems in time-dependent backgrounds is under consideration. We present some new exact solutions in special backgrounds decaying in time. On the other hand, following ideas of Feynman et al, we discuss in detail the possibility of reducing the quantum dynamics to a classical Hamiltonian system. This, in particular, opens the possibility of directly applying powerful methods of classical mechanics (e.g. KAM methods) to study the quantum system. Following such an approach, we draw conclusions of relevance for 'quantum chaos' when the external background is periodic or quasi-periodic in time. (author)

  9. Characteristics of the 2011 Tohoku Tsunami and introduction of two level tsunamis for tsunami disaster mitigation.

    Science.gov (United States)

    Sato, Shinji

    2015-01-01

    Characteristics of the 2011 Tohoku Tsunami have been revealed by collaborative tsunami surveys extensively performed under the coordination of the Joint Tsunami Survey Group. The complex behaviors of the mega-tsunami were characterized by the unprecedented scale and the low occurrence frequency. The limitation and the performance of tsunami countermeasures were described on the basis of tsunami surveys, laboratory experiments and numerical analyses. These findings contributed to the introduction of two-level tsunami hazards to establish a new strategy for tsunami disaster mitigation, combining structure-based flood protection designed by the Level-1 tsunami and non-structure-based damage reduction planned by the Level-2 tsunami.

  10. A January angular momentum balance in the OSU two-level atmospheric general circulation model

    Science.gov (United States)

    Kim, J.-W.; Grady, W.

    1982-01-01

    The present investigation is concerned with an analysis of the atmospheric angular momentum balance, based on the simulation data of the Oregon State University two-level atmospheric general circulation model (AGCM). An attempt is also made to gain an understanding of the involved processes. Preliminary results on the angular momentum and mass balance in the AGCM are shown. The basic equations are examined, and questions of turbulent momentum transfer are investigated. The methods of analysis are discussed, taking into account time-averaged balance equations, time and longitude-averaged balance equations, mean meridional circulation, the mean meridional balance of relative angular momentum, and standing and transient components of motion.

  11. Thermal analysis of two-level wind power converter under symmetrical grid fault

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede

    2013-01-01

    In this paper, the case of symmetrical grid fault when using the multi-MW wind turbine of partial-scale and full-scale two-level power converter are designed and investigated. Firstly, the different operation behaviors of the relevant power converters under the voltage dip will be described......) condition as well as the junction temperature. For the full-scale wind turbine system, the most thermal stressed power device in the grid-side converter will appear at the grid voltage below 0.5 pu, and for the partial-scale wind turbine system, the most thermal stressed power device in the rotor...

  12. Elimination of two level fluctuators in superconducting quantum bits by an epitaxial tunnel barrier

    International Nuclear Information System (INIS)

    Oh, Seongshik; Cicak, Katarina; Kline, Jeffrey S.; Sillanpaeae, Mika A.; Osborn, Kevin D.; Whittaker, Jed D.; Simmonds, Raymond W.; Pappas, David P.

    2006-01-01

    Quantum computing based on Josephson junction technology is considered promising due to its scalable architecture. However, decoherence is a major obstacle. Here, we report evidence for improved Josephson quantum bits (qubits) using a single-crystal Al 2 O 3 tunnel barrier. We have found an ∼80% reduction in the density of the spectral splittings that indicate the existence of two-level fluctators (TLFs) in amorphous tunnel barriers. The residual ∼20% TLFs can be attributed to interfacial effects that may be further reduced by different electrode materials. These results show that decoherence sources in the tunnel barrier of Josephson qubits can be identified and eliminated

  13. Limitations of two-level emitters as nonlinearities in two-photon controlled-PHASE gates

    DEFF Research Database (Denmark)

    Nysteen, Anders; McCutcheon, Dara P. S.; Heuck, Mikkel

    2017-01-01

    We investigate the origin of imperfections in the fidelity of a two-photon controlled-PHASE gate based on two-level-emitter nonlinearities. We focus on a passive system that operates without external modulations to enhance its performance. We demonstrate that the fidelity of the gate is limited...... by opposing requirements on the input pulse width for one-and two-photon-scattering events. For one-photon scattering, the spectral pulse width must be narrow compared with the emitter linewidth, while two-photon-scattering processes require the pulse width and emitter linewidth to be comparable. We find...

  14. Giant nonlinear interaction between two optical beams via a quantum dot embedded in a photonic wire

    Science.gov (United States)

    Nguyen, H. A.; Grange, T.; Reznychenko, B.; Yeo, I.; de Assis, P.-L.; Tumanov, D.; Fratini, F.; Malik, N. S.; Dupuy, E.; Gregersen, N.; Auffèves, A.; Gérard, J.-M.; Claudon, J.; Poizat, J.-Ph.

    2018-05-01

    Optical nonlinearities usually appear for large intensities, but discrete transitions allow for giant nonlinearities operating at the single-photon level. This has been demonstrated in the last decade for a single optical mode with cold atomic gases, or single two-level systems coupled to light via a tailored photonic environment. Here, we demonstrate a two-mode giant nonlinearity with a single semiconductor quantum dot (QD) embedded in a photonic wire antenna. We exploit two detuned optical transitions associated with the exciton-biexciton QD level scheme. Owing to the broadband waveguide antenna, the two transitions are efficiently interfaced with two free-space laser beams. The reflection of one laser beam is then controlled by the other beam, with a threshold power as low as 10 photons per exciton lifetime (1.6 nW ). Such a two-color nonlinearity opens appealing perspectives for the realization of ultralow-power logical gates and optical quantum gates, and could also be implemented in an integrated photonic circuit based on planar waveguides.

  15. Atomic physics

    CERN Document Server

    Born, Max

    1969-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  16. Early Atomism

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/reso/015/10/0905-0925. Keywords. Atomic theory; Avogadro's hypothesis; atomic weights; periodic table; valence; molecular weights; molecular formula; isomerism. Author Affiliations. S Ramasesha1. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, ...

  17. Atom spectroscopy

    International Nuclear Information System (INIS)

    Kodling, K.

    1981-01-01

    Experiments on atom photoabsorption spectroscopy using synchrotron radiation in the 10-1000 eV range are reviewed. Properties of the necessary synchrotron radiation and the experiment on absorption spectroscopy are briefly described. Comparison with other spectroscopy methods is conducted. Some data on measuring photoabsorption, photoelectron emission and atom mass spectra are presented [ru

  18. Exotic atoms

    International Nuclear Information System (INIS)

    Horvath, D.; Lambrecht, R.M.

    1984-01-01

    This bibliography on exotic atoms covers the years 1939 till 1982. The annual entries are headed by an introduction describing the state of affairs of the branch of science and listing the main applications in quantum electrodynamics, particle physics, nuclear physics, atomic physics, chemical physics and biological sciences. The bibliography includes an author index and a subject index. (Auth.)

  19. SCREENING OF MEDIUM COMPOUNDS USING A TWO-LEVEL FACTORIAL DESIGN FOR SACCHAROMYCES BOULARDII

    Directory of Open Access Journals (Sweden)

    GUOWEI SHU

    2016-04-01

    Full Text Available Even if the probiotic effect of Saccharomyces boulardii is has been reported, this yeast is rarely used in medium composition. Based on single factor experiment, two-level factorial design was employed to evaluate the effect of carbon sources (sucrose, glucose, nitrogen sources (soy peptone, beef extract, yeast extract, calf serum, malt extract and salts (K2HPO4, KH2PO4, MgSO4, Na2HPO4, NaH2PO4, CaCl2, sodium citrate, sodium glutamate on the growth of S. boulardii. At the same time, the optical density (OD in the medium was measured at 560 nm after 36 h of incubation. The result of two-level factorial design experiment showed that calf serum (p = 0.0214 and sodium citrate (p = 0.0045 are the significant growth factors of S. boulardii, sucrose (p = 0.0861 and malt extract (p = 0.0763 are important factors. In addition, sucrose and sodium citrate showed positive effect on the growth of S. boulardii. However, calf serum and malt extract showed negative effect on the growth. And we determined that the optimum medium composition for S. boulardii was as follow: 37.5 g·L-1 sucrose, 6 g·L-1 calf serum, 6 g·L-1 malt extract, 5 g·L-1 sodium citrate.

  20. Improved Genetic Algorithm with Two-Level Approximation for Truss Optimization by Using Discrete Shape Variables

    Directory of Open Access Journals (Sweden)

    Shen-yan Chen

    2015-01-01

    Full Text Available This paper presents an Improved Genetic Algorithm with Two-Level Approximation (IGATA to minimize truss weight by simultaneously optimizing size, shape, and topology variables. On the basis of a previously presented truss sizing/topology optimization method based on two-level approximation and genetic algorithm (GA, a new method for adding shape variables is presented, in which the nodal positions are corresponding to a set of coordinate lists. A uniform optimization model including size/shape/topology variables is established. First, a first-level approximate problem is constructed to transform the original implicit problem to an explicit problem. To solve this explicit problem which involves size/shape/topology variables, GA is used to optimize individuals which include discrete topology variables and shape variables. When calculating the fitness value of each member in the current generation, a second-level approximation method is used to optimize the continuous size variables. With the introduction of shape variables, the original optimization algorithm was improved in individual coding strategy as well as GA execution techniques. Meanwhile, the update strategy of the first-level approximation problem was also improved. The results of numerical examples show that the proposed method is effective in dealing with the three kinds of design variables simultaneously, and the required computational cost for structural analysis is quite small.

  1. Two-level method for unsteady Navier-Stokes equations based on a new projection

    International Nuclear Information System (INIS)

    Hou Yanren; Li Kaitai

    2004-12-01

    A two-level algorithm for the two dimensional unsteady Navier-Stokes equations based on a new projection is proposed and investigated. The approximate solution is solved as a sum of a large eddy component and a small eddy component, which are in the sense of the new projection, constructed in this paper. These two terms advance in time explicitly. Actually, the new algorithm proposed here can be regarded as a sort of postprocessing algorithm for the standard Galerkin method (SGM). The large eddy part is solved by SGM in the usual L 2 -based large eddy subspace while the small eddy part (the correction part) is obtained in its complement subspace in the sense of the new projection. The stability analysis indicates the improvement of the stability comparing with SGM of the same scale, and the L 2 -error estimate shows that the scheme can improve the accuracy of SGM approximation for half order. We also propose a numerical implementation based on Lagrange multiplier for this two-level algorithm. (author)

  2. Development and evaluation of a two-level functional structure for the thin film encapsulation

    International Nuclear Information System (INIS)

    Lee, Jae-Wung; Sharma, Jaibir; Singh, Navab; Kwong, Dim-Lee

    2013-01-01

    This paper reports a two level capping structure for encapsulating micro-electro-mechanical system (MEMS) devices. The two level capping solves the main issue of the longer release time as well as safe sealing in thin film encapsulation (TFE). In this technique, the first cap layer has many etch holes, which were uniformly distributed on it to enhance the removal of the sacrificial layer. The second cap layer forms a cap on every etch hole in the first cap layer to protect the mass loading on MEMS devices. This technique was found to be very effective in reducing the release time of the TFE. For the 1200 µm × 1200 µm sized cavity encapsulation, this technique decreases the release time of the TFE by a factor of 24 in comparison to the sidewall located channel scheme. The presented technique also helps in reducing the size of TFE as the etch holes are uniformly distributed on the TFE itself. Wide seal rings were not required to accommodate sidewall channels. (paper)

  3. Two-level Robust Measurement Fusion Kalman Filter for Clustering Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; QI Wen-Juan; DENG Zi-Li

    2014-01-01

    This paper investigates the distributed fusion Kalman filtering over clustering sensor networks. The sensor network is partitioned as clusters by the nearest neighbor rule and each cluster consists of sensing nodes and cluster-head. Using the minimax robust estimation principle, based on the worst-case conservative system with the conservative upper bounds of noise variances, two-level robust measurement fusion Kalman filter is presented for the clustering sensor network systems with uncertain noise variances. It can significantly reduce the communication load and save energy when the number of sensors is very large. A Lyapunov equation approach for the robustness analysis is presented, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented, and the robust accuracy relations among the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the two-level weighted measurement fuser is equal to that of the global centralized robust fuser and is higher than those of each local robust filter and each local weighted measurement fuser. A simulation example shows the correctness and effectiveness of the proposed results.

  4. A Weighted Two-Level Bregman Method with Dictionary Updating for Nonconvex MR Image Reconstruction

    Directory of Open Access Journals (Sweden)

    Qiegen Liu

    2014-01-01

    Full Text Available Nonconvex optimization has shown that it needs substantially fewer measurements than l1 minimization for exact recovery under fixed transform/overcomplete dictionary. In this work, two efficient numerical algorithms which are unified by the method named weighted two-level Bregman method with dictionary updating (WTBMDU are proposed for solving lp optimization under the dictionary learning model and subjecting the fidelity to the partial measurements. By incorporating the iteratively reweighted norm into the two-level Bregman iteration method with dictionary updating scheme (TBMDU, the modified alternating direction method (ADM solves the model of pursuing the approximated lp-norm penalty efficiently. Specifically, the algorithms converge after a relatively small number of iterations, under the formulation of iteratively reweighted l1 and l2 minimization. Experimental results on MR image simulations and real MR data, under a variety of sampling trajectories and acceleration factors, consistently demonstrate that the proposed method can efficiently reconstruct MR images from highly undersampled k-space data and presents advantages over the current state-of-the-art reconstruction approaches, in terms of higher PSNR and lower HFEN values.

  5. Detuning-induced stimulated Raman adiabatic passage in dense two-level systems

    Science.gov (United States)

    Deng, Li; Lin, Gongwei; Niu, Yueping; Gong, Shangqing

    2018-05-01

    We investigate the coherence generation in dense two-level systems under detuning-induced stimulated Raman adiabatic passage (D-STIRAP). In the dense two-level system, the near dipole-dipole (NDD) interaction should be taken into consideration. With the increase in the strength of the NDD interaction, it is found that a switchlike transition of the generated coherence from maximum value to zero appears. Meanwhile, the adiabatic condition of the D-STIRAP is destroyed in the presence of the NDD interaction. In order to avoid the sudden decrease in the generated coherence and maintain the maximum value, we can use stronger detuning pulse or pump pulse, between which increasing the intensity of the detuning pulse is of more efficiency. Except for taking advantage of such maximum coherence in the high density case into areas like enhancing the four-wave mixing process, we also point out that the phenomenon of the coherence transition can be applied as an optical switch.

  6. A novel two-level dynamic parallel data scheme for large 3-D SN calculations

    International Nuclear Information System (INIS)

    Sjoden, G.E.; Shedlock, D.; Haghighat, A.; Yi, C.

    2005-01-01

    We introduce a new dynamic parallel memory optimization scheme for executing large scale 3-D discrete ordinates (Sn) simulations on distributed memory parallel computers. In order for parallel transport codes to be truly scalable, they must use parallel data storage, where only the variables that are locally computed are locally stored. Even with parallel data storage for the angular variables, cumulative storage requirements for large discrete ordinates calculations can be prohibitive. To address this problem, Memory Tuning has been implemented into the PENTRAN 3-D parallel discrete ordinates code as an optimized, two-level ('large' array, 'small' array) parallel data storage scheme. Memory Tuning can be described as the process of parallel data memory optimization. Memory Tuning dynamically minimizes the amount of required parallel data in allocated memory on each processor using a statistical sampling algorithm. This algorithm is based on the integral average and standard deviation of the number of fine meshes contained in each coarse mesh in the global problem. Because PENTRAN only stores the locally computed problem phase space, optimal two-level memory assignments can be unique on each node, depending upon the parallel decomposition used (hybrid combinations of angular, energy, or spatial). As demonstrated in the two large discrete ordinates models presented (a storage cask and an OECD MOX Benchmark), Memory Tuning can save a substantial amount of memory per parallel processor, allowing one to accomplish very large scale Sn computations. (authors)

  7. Phylogenetic trees and Euclidean embeddings.

    Science.gov (United States)

    Layer, Mark; Rhodes, John A

    2017-01-01

    It was recently observed by de Vienne et al. (Syst Biol 60(6):826-832, 2011) that a simple square root transformation of distances between taxa on a phylogenetic tree allowed for an embedding of the taxa into Euclidean space. While the justification for this was based on a diffusion model of continuous character evolution along the tree, here we give a direct and elementary explanation for it that provides substantial additional insight. We use this embedding to reinterpret the differences between the NJ and BIONJ tree building algorithms, providing one illustration of how this embedding reflects tree structures in data.

  8. Tensor Train Neighborhood Preserving Embedding

    Science.gov (United States)

    Wang, Wenqi; Aggarwal, Vaneet; Aeron, Shuchin

    2018-05-01

    In this paper, we propose a Tensor Train Neighborhood Preserving Embedding (TTNPE) to embed multi-dimensional tensor data into low dimensional tensor subspace. Novel approaches to solve the optimization problem in TTNPE are proposed. For this embedding, we evaluate novel trade-off gain among classification, computation, and dimensionality reduction (storage) for supervised learning. It is shown that compared to the state-of-the-arts tensor embedding methods, TTNPE achieves superior trade-off in classification, computation, and dimensionality reduction in MNIST handwritten digits and Weizmann face datasets.

  9. Schroedinger cat states and multilevel atoms

    International Nuclear Information System (INIS)

    Shore, B.W.; Knight, P.L.

    1993-01-01

    We demonstrate that the generalization of the two-level Jaynes-Cummings model (JCM) to an N-level atom leads to the creation of up to N macroscopically distinct field states. These field states are Schmidt-orthogonalized superpositions of Fock states. They correspond to macroscopic states of the field, attainable with large mean photon numbers. Unlike the situation with a two-level atom and a coherent-state field, which evolves into a macroscopic coherent superposition state (a Schrodinger cat), we find that when the additional levels participate strongly in the excitation (e.g all transitions are resonant with equal dipole moments) then the system does not evolve into a pure state. We will present some examples of special cases, giving insight into the behavior of three-level atoms and the two-level two-photon JCM

  10. Embedded random matrix ensembles in quantum physics

    CERN Document Server

    Kota, V K B

    2014-01-01

    Although used with increasing frequency in many branches of physics, random matrix ensembles are not always sufficiently specific to account for important features of the physical system at hand. One refinement which retains the basic stochastic approach but allows for such features consists in the use of embedded ensembles.  The present text is an exhaustive introduction to and survey of this important field. Starting with an easy-to-read introduction to general random matrix theory, the text then develops the necessary concepts from the beginning, accompanying the reader to the frontiers of present-day research. With some notable exceptions, to date these ensembles have primarily been applied in nuclear spectroscopy. A characteristic example is the use of a random two-body interaction in the framework of the nuclear shell model. Yet, topics in atomic physics, mesoscopic physics, quantum information science and statistical mechanics of isolated finite quantum systems can also be addressed using these ensemb...

  11. Parametric embedding for class visualization.

    Science.gov (United States)

    Iwata, Tomoharu; Saito, Kazumi; Ueda, Naonori; Stromsten, Sean; Griffiths, Thomas L; Tenenbaum, Joshua B

    2007-09-01

    We propose a new method, parametric embedding (PE), that embeds objects with the class structure into a low-dimensional visualization space. PE takes as input a set of class conditional probabilities for given data points and tries to preserve the structure in an embedding space by minimizing a sum of Kullback-Leibler divergences, under the assumption that samples are generated by a gaussian mixture with equal covariances in the embedding space. PE has many potential uses depending on the source of the input data, providing insight into the classifier's behavior in supervised, semisupervised, and unsupervised settings. The PE algorithm has a computational advantage over conventional embedding methods based on pairwise object relations since its complexity scales with the product of the number of objects and the number of classes. We demonstrate PE by visualizing supervised categorization of Web pages, semisupervised categorization of digits, and the relations of words and latent topics found by an unsupervised algorithm, latent Dirichlet allocation.

  12. Embedded System for Biometric Identification

    OpenAIRE

    Rosli, Ahmad Nasir Che

    2010-01-01

    This chapter describes the design and implementation of an Embedded System for Biometric Identification from hardware and software perspectives. The first part of the chapter describes the idea of biometric identification. This includes the definition of

  13. SUBJECT «NUMBER SYSTEMS» IN TWO-LEVELED FORMAT PREPARATION TEACHERS OF MATHEMATICS

    Directory of Open Access Journals (Sweden)

    V. I. Igoshin

    2017-01-01

    Full Text Available The aim of this article is to analyze the format of a two-leveled training – bachelor and master – future teachers of mathematics from the point of view of the content of mathematical material, which is to develop prospective teachers of mathematics at those two levels, shaping their professional competence.Methods. The study involves the theoretical methods: the analysis of pedagogical and methodical literature, normative documents; historical, comparative and logical analysis of the content of pedagogical mathematical education; forecasting, planning and designing of two-leveled methodical system of training of future teachers of mathematics.Results and scientific novelty. The level differentiation of the higher education system requires developing the appropriate curricula for undergraduate and graduate programs. The fundamental principle must be the principle of continuity – the magister must continue to deepen and broaden knowledge and skills, along with competences acquired, developed and formed on the undergraduate level. From these positions, this paper examines the course «Number Systems» – the most important in terms of methodology course for future mathematics teachers, and shows what content should be filled with this course at the undergraduate level and the graduate level. At the undergraduate level it is proposed to study classical number systems – natural, integer, rational, real and complex. Further extensions of the number systems are studied at the graduate level. The theory of numeric systems is presented as a theory of algebraic systems, arising at the intersection of algebra and mathematical logic. Here we study algebras over a field, division algebra over a field, an alternative algebra with division over the field, Jordan algebra, Lie algebra. Comprehension of bases of the theory of algebras by the master of the «mathematical education» profile will promote more conscious

  14. Computer simulation of two-level pedicle subtraction osteotomy for severe thoracolumbar kyphosis in ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2017-01-01

    Full Text Available Background: Advanced ankylosing spondylitis is often associated with thoracolumbar kyphosis, resulting in an abnormal spinopelvic balance and pelvic morphology. Different osteotomy techniques have been used to correct AS deformities, unfortunnaly, not all AS patients can gain spinal sagittal balance and good horizontal vision after osteotomy. Materials and Methods: Fourteen consecutive AS patients with severe thoracolumbar kyphosis who were treated with two-level PSO were studied retrospectively. All were male with a mean age of 34.9 ± 9.6 years. The followup ranged from 1–5 years. Preoperative computer simulations using the Surgimap Spinal software were performed for all patients, and the osteotomy level and angle determined from the computer simulation were used surgically. Spinal sagittal parameters were measured preoperatively, after the computer simulation, and postoperatively and included thoracic kyphosis (TK, lumbar lordosis (LL, sagittal vertical axis (SVA, pelvic incidence, pelvic tilt (PT, and sacral slope (SS. The level of correlation between the computer simulation and postoperative parameters was evaluated, and the differences between preoperative and postoperative parameters were compared. The visual analog scale (VAS for back pain and clinical outcome was also assessed. Results: Six cases underwent PSO at L1 and L3, five cases at L2 and T12, and three cases at L3 and T12. TK was corrected from 57.8 ± 15.2° preoperatively to 45.3 ± 7.7° postoperatively (P < 0.05, LL from 9.3 ± 17.5° to −52.3 ± 3.9° (P < 0.001, SVA from 154.5 ± 36.7 to 37.8 ± 8.4 mm (P < 0.001, PT from 43.3 ± 6.1° to 18.0 ± 0.9° (P < 0.001, and SS from 0.8 ± 7.0° to 26.5 ± 10.6° (P < 0.001. The LL, VAS, and PT of the simulated two-level PSO were highly consistent with, or almost the same as, the postoperative parameters. The correlations between the computer simulations and postoperative parameters were significant. The VAS decreased

  15. Comprehensive solutions to the Bloch equations and dynamical models for open two-level systems

    Science.gov (United States)

    Skinner, Thomas E.

    2018-01-01

    The Bloch equation and its variants constitute the fundamental dynamical model for arbitrary two-level systems. Many important processes, including those in more complicated systems, can be modeled and understood through the two-level approximation. It is therefore of widespread relevance, especially as it relates to understanding dissipative processes in current cutting-edge applications of quantum mechanics. Although the Bloch equation has been the subject of considerable analysis in the 70 years since its inception, there is still, perhaps surprisingly, significant work that can be done. This paper extends the scope of previous analyses. It provides a framework for more fully understanding the dynamics of dissipative two-level systems. A solution is derived that is compact, tractable, and completely general, in contrast to previous results. Any solution of the Bloch equation depends on three roots of a cubic polynomial that are crucial to the time dependence of the system. The roots are typically only sketched out qualitatively, with no indication of their dependence on the physical parameters of the problem. Degenerate roots, which modify the solutions, have been ignored altogether. Here the roots are obtained explicitly in terms of a single real-valued root that is expressed as a simple function of the system parameters. For the conventional Bloch equation, a simple graphical representation of this root is presented that makes evident the explicit time dependence of the system for each point in the parameter space. Several intuitive, visual models of system dynamics are developed. A Euclidean coordinate system is identified in which any generalized Bloch equation is separable, i.e., the sum of commuting rotation and relaxation operators. The time evolution in this frame is simply a rotation followed by relaxation at modified rates that play a role similar to the standard longitudinal and transverse rates. These rates are functions of the applied field, which

  16. Positron confinement in embedded lithium nanoclusters

    Science.gov (United States)

    van Huis, M. A.; van Veen, A.; Schut, H.; Falub, C. V.; Eijt, S. W.; Mijnarends, P. E.; Kuriplach, J.

    2002-02-01

    Quantum confinement of positrons in nanoclusters offers the opportunity to obtain detailed information on the electronic structure of nanoclusters by application of positron annihilation spectroscopy techniques. In this work, positron confinement is investigated in lithium nanoclusters embedded in monocrystalline MgO. These nanoclusters were created by means of ion implantation and subsequent annealing. It was found from the results of Doppler broadening positron beam analysis that approximately 92% of the implanted positrons annihilate in lithium nanoclusters rather than in the embedding MgO, while the local fraction of lithium at the implantation depth is only 1.3 at. %. The results of two-dimensional angular correlation of annihilation radiation confirm the presence of crystalline bulk lithium. The confinement of positrons is ascribed to the difference in positron affinity between lithium and MgO. The nanocluster acts as a potential well for positrons, where the depth of the potential well is equal to the difference in the positron affinities of lithium and MgO. These affinities were calculated using the linear muffin-tin orbital atomic sphere approximation method. This yields a positronic potential step at the MgO||Li interface of 1.8 eV using the generalized gradient approximation and 2.8 eV using the insulator model.

  17. First-principles study of H, O, and N adsorption on metal embedded carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Detian [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Luo, Haijun, E-mail: luohaijun@wzu.edu.cn [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cai, Jianqiu [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cheng, Yongjun [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Shao, Xiji [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Dong, Changkun, E-mail: dck@wzu.edu.cn [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China)

    2017-05-01

    Highlights: • Ni or Fe embedment and high atomic adsorption coverage benefit applications like hydrogen storage and field emission. • Ni or Fe embedment could help tune the catalytic properties. • Ni or Fe embedment enhances the adatom-SWNT interaction significantly. - Abstract: The density functional theory calculation has been conducted to investigate the structural and electronic properties, including the adsorption energies, bond structures, work functions, charge transfer behaviors, and density of states for pristine, Ni-, and Fe-embedded capped (5, 5) single-walled carbon nanotubes (SWNTs) with different coverage of atomic hydrogen, oxygen, and nitrogen adsorptions. Ni or Fe embedment enhances the adatom-SWNT interactions significantly for three kinds of gas atoms with the increases of the adsorption energies. The SWNT work function drops with H adsorption, while Ni or Fe embedment assists further the reduction. When increasing the coverage, the adsorption energy decreases and the work function climbs for O adsorption, but the nitrogen adsorption energy increases. The Bader charge transfer analysis implies that the cap possesses higher oxygen reduction activities than the tube, and the density of states analysis shows that Ni or Fe embedment deepens the C-adatom hybridizations.

  18. Atomic fusion, Gerrard atomic fusion

    International Nuclear Information System (INIS)

    Gerrard, T.H.

    1980-01-01

    In the approach to atomic fusion described here the heat produced in a fusion reaction, which is induced in a chamber by the interaction of laser beams and U.H.F. electromagnetic beams with atom streams, is transferred to a heat exchanger for electricity generation by a coolant flowing through a jacket surrounding the chamber. (U.K.)

  19. Hardware Support for Embedded Java

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2012-01-01

    The general Java runtime environment is resource hungry and unfriendly for real-time systems. To reduce the resource consumption of Java in embedded systems, direct hardware support of the language is a valuable option. Furthermore, an implementation of the Java virtual machine in hardware enables...... worst-case execution time analysis of Java programs. This chapter gives an overview of current approaches to hardware support for embedded and real-time Java....

  20. Molecular Properties through Polarizable Embedding

    DEFF Research Database (Denmark)

    Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob

    2011-01-01

    We review the theory related to the calculation of electric and magnetic molecular properties through polarizable embedding. In particular, we derive the expressions for the response functions up to the level of cubic response within the density functional theory-based polarizable embedding (PE......-DFT) formalism. In addition, we discuss some illustrative applications related to the calculation of nuclear magnetic resonance parameters, nonlinear optical properties, and electronic excited states in solution....

  1. A Foundation for Embedded Languages

    DEFF Research Database (Denmark)

    Rhiger, Morten

    2003-01-01

    Recent work on embedding object languages into Haskell use "phantom types" (i.e., parameterized types whose parameter does not occur on the right-hand side of the type definition) to ensure that the embedded object-language terms are simply typed. But is it a safe assumption that only simply...... be answered affirmatively for an idealized Haskell-like language and discuss to which extent Haskell can be used as a meta-language....

  2. Unsupervised Document Embedding With CNNs

    OpenAIRE

    Liu, Chundi; Zhao, Shunan; Volkovs, Maksims

    2017-01-01

    We propose a new model for unsupervised document embedding. Leading existing approaches either require complex inference or use recurrent neural networks (RNN) that are difficult to parallelize. We take a different route and develop a convolutional neural network (CNN) embedding model. Our CNN architecture is fully parallelizable resulting in over 10x speedup in inference time over RNN models. Parallelizable architecture enables to train deeper models where each successive layer has increasin...

  3. Two-Level Chebyshev Filter Based Complementary Subspace Method: Pushing the Envelope of Large-Scale Electronic Structure Calculations.

    Science.gov (United States)

    Banerjee, Amartya S; Lin, Lin; Suryanarayana, Phanish; Yang, Chao; Pask, John E

    2018-06-12

    We describe a novel iterative strategy for Kohn-Sham density functional theory calculations aimed at large systems (>1,000 electrons), applicable to metals and insulators alike. In lieu of explicit diagonalization of the Kohn-Sham Hamiltonian on every self-consistent field (SCF) iteration, we employ a two-level Chebyshev polynomial filter based complementary subspace strategy to (1) compute a set of vectors that span the occupied subspace of the Hamiltonian; (2) reduce subspace diagonalization to just partially occupied states; and (3) obtain those states in an efficient, scalable manner via an inner Chebyshev filter iteration. By reducing the necessary computation to just partially occupied states and obtaining these through an inner Chebyshev iteration, our approach reduces the cost of large metallic calculations significantly, while eliminating subspace diagonalization for insulating systems altogether. We describe the implementation of the method within the framework of the discontinuous Galerkin (DG) electronic structure method and show that this results in a computational scheme that can effectively tackle bulk and nano systems containing tens of thousands of electrons, with chemical accuracy, within a few minutes or less of wall clock time per SCF iteration on large-scale computing platforms. We anticipate that our method will be instrumental in pushing the envelope of large-scale ab initio molecular dynamics. As a demonstration of this, we simulate a bulk silicon system containing 8,000 atoms at finite temperature, and obtain an average SCF step wall time of 51 s on 34,560 processors; thus allowing us to carry out 1.0 ps of ab initio molecular dynamics in approximately 28 h (of wall time).

  4. Superradiators created atom by atom

    Science.gov (United States)

    Meschede, Dieter

    2018-02-01

    High radiation rates are usually associated with macroscopic lasers. Laser radiation is “coherent”—its amplitude and phase are well-defined—but its generation requires energy inputs to overcome loss. Excited atoms spontaneously emit in a random and incoherent fashion, and for N such atoms, the emission rate simply increases as N. However, if these atoms are in close proximity and coherently coupled by a radiation field, this microscopic ensemble acts as a single emitter whose emission rate increases as N2 and becomes “superradiant,” to use Dicke's terminology (1). On page 662 of this issue, Kim et al. (2) show the buildup of coherent light fields through collective emission from atomic radiators injected one by one into a resonator field. There is only one atom ever in the cavity, but the emission is still collective and superradiant. These results suggest another route toward thresholdless lasing.

  5. Canyon of current suppression in an interacting two-level quantum dot

    DEFF Research Database (Denmark)

    Karlström, O; Pedersen, Jonas Nyvold; Samuelsson, P

    2011-01-01

    Motivated by the recent discovery of a canyon of conductance suppression in a two-level equal-spin quantum dot system [Phys. Rev. Lett. 104, 186804 (2010)], the transport through this system is studied in detail. At low bias and low temperature a strong current suppression is found around...... the electron-hole symmetry point independent of the couplings, in agreement with previous results. By means of a Schrieffer–Wolff transformation we are able to give an intuitive explanation to this suppression in the low-energy regime. In the general situation, numerical simulations are carried out using...... for the current suppression. It is also shown how broadening, interference, and a finite interaction energy cause a shift of the current minimum away from degeneracy. Finally we see how an increased population of the upper level leads to current peaks on each side of the suppression line. At sufficiently high...

  6. Propagation of an attosecond pulse in a dense two-level medium

    International Nuclear Information System (INIS)

    Song Xiaohong; Gong Shangqing; Yang Weifeng; Xu Zhizhan

    2004-01-01

    We investigate the propagation of attosecond pulse in a dense two-level medium by using an iterative predictor-corrector finite-difference time-domain method. We find when attosecond pulse is considered, that the standard area theorem will break down even for small area pulses: ideal self-induced transparency cannot occur even for a 2π pulse, while the pulses whose areas are not integer multiples of 2π, such as 1.8π and 2.2π pulses, cannot evolve to 2π pulses as predicted by the standard area theorem. Significantly higher spectra components can occur on all these small area propagating pulses due to strong carrier reshaping. Furthermore, these higher spectral components dependent sensitively on the pulse area: the larger the pulse area is, the more evident are these higher spectral components

  7. Transmission-line resonators for the study of individual two-level tunneling systems

    Science.gov (United States)

    Brehm, Jan David; Bilmes, Alexander; Weiss, Georg; Ustinov, Alexey V.; Lisenfeld, Jürgen

    2017-09-01

    Parasitic two-level tunneling systems (TLS) emerge in amorphous dielectrics and constitute a serious nuisance for various microfabricated devices, where they act as a source of noise and decoherence. Here, we demonstrate a new test bed for the study of TLS in various materials which provides access to properties of individual TLS as well as their ensemble response. We terminate a superconducting transmission-line resonator with a capacitor that hosts TLS in its dielectric. By tuning TLS via applied mechanical strain, we observe the signatures of individual TLS strongly coupled to the resonator in its transmission characteristics and extract the coupling components of their dipole moments and energy relaxation rates. The strong and well-defined coupling to the TLS bath results in pronounced resonator frequency fluctuations and excess phase noise, through which we can study TLS ensemble effects such as spectral diffusion, and probe theoretical models of TLS interactions.

  8. Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Clemens [ARC Centre of Excellence for Engineered Quantum Systems, The University of Queensland, Brisbane (Australia); Lisenfeld, Juergen [Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe (Germany); Shnirman, Alexander [Institut fuer Theory der Kondensierten Materie, Karlsruhe Institute of Technology, Karlsruhe (Germany); LD Landau Institute for Theoretical Physics, Moscow (Russian Federation); Poletto, Stefano [IBM TJ Watson Research Centre, Yorktown Heights (United States)

    2016-07-01

    Since the very first experiments, superconducting circuits have suffered from strong coupling to environmental noise, destroying quantum coherence and degrading performance. In state-of-the-art experiments, it is found that the relaxation time of superconducting qubits fluctuates as a function of time. We present measurements of such fluctuations in a 3D-transmon circuit and develop a qualitative model based on interactions within a bath of background two-level systems (TLS) which emerge from defects in the device material. In our model, the time-dependent noise density acting on the qubit emerges from its near-resonant coupling to high-frequency TLS which experience energy fluctuations due to their interaction with thermally fluctuating TLS at low frequencies. We support the model by providing experimental evidence of such energy fluctuations observed in a single TLS in a phase qubit circuit.

  9. Two-Level Hierarchical FEM Method for Modeling Passive Microwave Devices

    Science.gov (United States)

    Polstyanko, Sergey V.; Lee, Jin-Fa

    1998-03-01

    In recent years multigrid methods have been proven to be very efficient for solving large systems of linear equations resulting from the discretization of positive definite differential equations by either the finite difference method or theh-version of the finite element method. In this paper an iterative method of the multiple level type is proposed for solving systems of algebraic equations which arise from thep-version of the finite element analysis applied to indefinite problems. A two-levelV-cycle algorithm has been implemented and studied with a Gauss-Seidel iterative scheme used as a smoother. The convergence of the method has been investigated, and numerical results for a number of numerical examples are presented.

  10. Estimation of Missing Observations in Two-Level Split-Plot Designs

    DEFF Research Database (Denmark)

    Almimi, Ashraf A.; Kulahci, Murat; Montgomery, Douglas C.

    2008-01-01

    Inserting estimates for the missing observations from split-plot designs restores their balanced or orthogonal structure and alleviates the difficulties in the statistical analysis. In this article, we extend a method due to Draper and Stoneman to estimate the missing observations from unreplicated...... two-level factorial and fractional factorial split-plot (FSP and FFSP) designs. The missing observations, which can either be from the same whole plot, from different whole plots, or comprise entire whole plots, are estimated by equating to zero a number of specific contrast columns equal...... to the number of the missing observations. These estimates are inserted into the design table and the estimates for the remaining effects (or alias chains of effects as the case with FFSP designs) are plotted on two half-normal plots: one for the whole-plot effects and the other for the subplot effects...

  11. Thermal analysis of multi-MW two-level wind power converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Mogens, Lau

    2012-01-01

    In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature...... in the power device in the whole range of wind speed are presented and analyzed. It is concluded that in both partial-scale and full-scale power converter the most thermal stressed power device in the generator-side converter will have higher mean junction temperature and larger junction temperature...... fluctuation compared to grid-side converter at the rated wind speed. Moreover, the thermal performance of the generator-side converter in the partial-scale power converter becomes crucial around the synchronous operating point and should be considered carefully....

  12. Two-Level Verification of Data Integrity for Data Storage in Cloud Computing

    Science.gov (United States)

    Xu, Guangwei; Chen, Chunlin; Wang, Hongya; Zang, Zhuping; Pang, Mugen; Jiang, Ping

    Data storage in cloud computing can save capital expenditure and relive burden of storage management for users. As the lose or corruption of files stored may happen, many researchers focus on the verification of data integrity. However, massive users often bring large numbers of verifying tasks for the auditor. Moreover, users also need to pay extra fee for these verifying tasks beyond storage fee. Therefore, we propose a two-level verification of data integrity to alleviate these problems. The key idea is to routinely verify the data integrity by users and arbitrate the challenge between the user and cloud provider by the auditor according to the MACs and ϕ values. The extensive performance simulations show that the proposed scheme obviously decreases auditor's verifying tasks and the ratio of wrong arbitration.

  13. Two Level Versus Matrix Converters Performance in Wind Energy Conversion Systems Employing DFIG

    Science.gov (United States)

    Reddy, Gongati Pandu Ranga; Kumar, M. Vijaya

    2017-10-01

    Wind power capacity has received enormous growth during past decades. With substantial development of wind power, it is expected to provide a fifth of world's electricity by the end of 2030. In wind energy conversion system, the power electronic converters play an important role. This paper presents the two level and matrix converters performance in wind energy conversion system employing Doubly Fed Induction Generator (DFIG). The DFIG is a wound rotor induction generator. Because of the advantages of the DFIG over other generators it is being used for most of the wind applications. This paper also discusses control of converters using the space vector pulse width modulation technique. The MATLAB/SIMULINK ® software is used to study the performance of the converters.

  14. Phonon induced optical gain in a current carrying two-level quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Eskandari-asl, Amir, E-mail: amir.eskandari.asl@gmail.com [Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran 1983963113 (Iran, Islamic Republic of); School of Nano Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box: 19395-5531, Tehran, Iran (Iran, Islamic Republic of)

    2017-05-15

    In this work we consider a current carrying two level quantum dot (QD) that is coupled to a single mode phonon bath. Using self-consistent Hartree-Fock approximation, we obtain the I-V curve of QD. By considering the linear response of our system to an incoming classical light, we see that depending on the parametric regime, the system could have weak or strong light absorption or may even show lasing. This lasing occurs at high enough bias voltages and is explained by a population inversion considering side bands, while the total electron population in the higher level is less than the lower one. The frequency at which we have the most significant lasing depends on the level spacing and phonon frequency and not on the electron-phonon coupling strength.

  15. TWO-LEVEL HIERARCHICAL COORDINATION QUEUING METHOD FOR TELECOMMUNICATION NETWORK NODES

    Directory of Open Access Journals (Sweden)

    M. V. Semenyaka

    2014-07-01

    Full Text Available The paper presents hierarchical coordination queuing method. Within the proposed method a queuing problem has been reduced to optimization problem solving that was presented as two-level hierarchical structure. The required distribution of flows and bandwidth allocation was calculated at the first level independently for each macro-queue; at the second level solutions obtained on lower level for each queue were coordinated in order to prevent probable network link overload. The method of goal coordination has been determined for multilevel structure managing, which makes it possible to define the order for consideration of queue cooperation restrictions and calculation tasks distribution between levels of hierarchy. Decisions coordination was performed by the method of Lagrange multipliers. The study of method convergence has been carried out by analytical modeling.

  16. On Two-Level State-Dependent Routing Polling Systems with Mixed Service

    Directory of Open Access Journals (Sweden)

    Guan Zheng

    2015-01-01

    Full Text Available Based on priority differentiation and efficiency of the system, we consider an N+1 queues’ single-server two-level polling system which consists of one key queue and N normal queues. The novel contribution of the present paper is that we consider that the server just polls active queues with customers waiting in the queue. Furthermore, key queue is served with exhaustive service and normal queues are served with 1-limited service in a parallel scheduling. For this model, we derive an expression for the probability generating function of the joint queue length distribution at polling epochs. Based on these results, we derive the explicit closed-form expressions for the mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical and the new system is efficient both at key queue and normal queues.

  17. Intensity profiles of superdeformed bands in Pb isotopes in a two-level mixing model

    International Nuclear Information System (INIS)

    Wilson, A. N.; Szigeti, S. S.; Rogers, J. I.; Davidson, P. M.; Cardamone, D. M.

    2009-01-01

    A recently developed two-level mixing model of the decay out of superdeformed bands is applied to examine the loss of flux from the yrast superdeformed bands in 192 Pb, 194 Pb, and 196 Pb. Probability distributions for decay to states at normal deformations are calculated at each level. The sensitivity of the results to parameters describing the levels at normal deformation and their coupling to levels in the superdeformed well is explored. It is found that except for narrow ranges of the interaction strength coupling the states, the amount of intensity lost is primarily determined by the ratio of γ decay widths in the normal and superdeformed wells. It is also found that while the model can accommodate the observed fractional intensity loss profiles for decay from bands at relatively high excitation, it cannot accommodate the similarly abrupt decay from bands at lower energies if standard estimates of the properties of the states in the first minimum are employed

  18. Faithful state transfer between two-level systems via an actively cooled finite-temperature cavity

    Science.gov (United States)

    Sárkány, Lőrinc; Fortágh, József; Petrosyan, David

    2018-03-01

    We consider state transfer between two qubits—effective two-level systems represented by Rydberg atoms—via a common mode of a microwave cavity at finite temperature. We find that when both qubits have the same coupling strength to the cavity field, at large enough detuning from the cavity mode frequency, quantum interference between the transition paths makes the swap of the excitation between the qubits largely insensitive to the number of thermal photons in the cavity. When, however, the coupling strengths are different, the photon-number-dependent differential Stark shift of the transition frequencies precludes efficient transfer. Nevertheless, using an auxiliary cooling system to continuously extract the cavity photons, we can still achieve a high-fidelity state transfer between the qubits.

  19. Two-level modulation scheme to reduce latency for optical mobile fronthaul networks.

    Science.gov (United States)

    Sung, Jiun-Yu; Chow, Chi-Wai; Yeh, Chien-Hung; Chang, Gee-Kung

    2016-10-31

    A system using optical two-level orthogonal-frequency-division-multiplexing (OFDM) - amplitude-shift-keying (ASK) modulation is proposed and demonstrated to reduce the processing latency for the optical mobile fronthaul networks. At the proposed remote-radio-head (RRH), the high data rate OFDM signal does not need to be processed, but is directly launched into a high speed photodiode (HSPD) and subsequently emitted by an antenna. Only a low bandwidth PD is needed to recover the low data rate ASK control signal. Hence, it is simple and provides low-latency. Furthermore, transporting the proposed system over the already deployed optical-distribution-networks (ODNs) of passive-optical-networks (PONs) is also demonstrated with 256 ODN split-ratios.

  20. Indoor Semantic Modelling for Routing: The Two-Level Routing Approach for Indoor Navigation

    Directory of Open Access Journals (Sweden)

    Liu Liu

    2017-11-01

    Full Text Available Humans perform many activities indoors and they show a growing need for indoor navigation, especially in unfamiliar buildings such as airports, museums and hospitals. Complexity of such buildings poses many challenges for building managers and visitors. Indoor navigation services play an important role in supporting these indoor activities. Indoor navigation covers extensive topics such as: 1 indoor positioning and localization; 2 indoor space representation for navigation model generation; 3 indoor routing computation; 4 human wayfinding behaviours; and 5 indoor guidance (e.g., textual directories. So far, a large number of studies of pedestrian indoor navigation have presented diverse navigation models and routing algorithms/methods. However, the major challenge is rarely referred to: how to represent the complex indoor environment for pedestrians and conduct routing according to the different roles and sizes of users. Such complex buildings contain irregular shapes, large open spaces, complicated obstacles and different types of passages. A navigation model can be very complicated if the indoors are accurately represented. Although most research demonstrates feasible indoor navigation models and related routing methods in regular buildings, the focus is still on a general navigation model for pedestrians who are simplified as circles. In fact, pedestrians represent different sizes, motion abilities and preferences (e.g., described in user profiles, which should be reflected in navigation models and be considered for indoor routing (e.g., relevant Spaces of Interest and Points of Interest. In order to address this challenge, this thesis proposes an innovative indoor modelling and routing approach – two-level routing. It specially targets the case of routing in complex buildings for distinct users. The conceptual (first level uses general free indoor spaces: this is represented by the logical network whose nodes represent the spaces and edges

  1. Segmental and global lordosis changes with two-level axial lumbar interbody fusion and posterior instrumentation

    Science.gov (United States)

    Melgar, Miguel A; Tobler, William D; Ernst, Robert J; Raley, Thomas J; Anand, Neel; Miller, Larry E; Nasca, Richard J

    2014-01-01

    Background Loss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes. Methods We performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months). Results There was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change. Conclusions/Clinical Relevance Two-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change. PMID:25694920

  2. Atomic interferometry

    International Nuclear Information System (INIS)

    Baudon, J.; Robert, J.

    2004-01-01

    Since the theoretical works of L. De Broglie (1924) and the famous experiment of Davisson and Germer (1927), we know that a wave is linked with any particle of mass m by the relation λ = h/(mv), where λ is the wavelength, v the particle velocity and h is the Planck constant. The basic principle of the interferometry of any material particle, atom, molecule or aggregate is simple: using a simple incident wave, several mutually consistent waves (with well-defined relative phases) are generated and controllable phase-shifts are introduced between them in order to generate a wave which is the sum of the previous waves. An interference figure is obtained which consists in a succession of dark and bright fringes. The atomic interferometry is based on the same principle but involves different techniques, different wave equations, but also different beams, sources and correlations which are described in this book. Because of the small possible wavelengths and the wide range of possible atomic interactions, atomic interferometers can be used in many domains from the sub-micron lithography to the construction of sensors like: inertial sensors, gravity-meters, accelerometers, gyro-meters etc. The first chapter is a preliminary study of the space and time diffraction of atoms. The next chapters is devoted to the description of slit, light separation and polarization interferometers, and the last chapter treats of the properties of Bose-Einstein condensates which are interesting in atomic interferometry. (J.S.)

  3. Structure and magnetism in Cr-embedded Co nanoparticles.

    Science.gov (United States)

    Baker, S H; Kurt, M S; Roy, M; Lees, M R; Binns, C

    2016-02-03

    We present the results of an investigation into the atomic structure and magnetism of 2 nm diameter Co nanoparticles embedded in an antiferromagnetic Cr matrix. The nanocomposite films used in this study were prepared by co-deposition directly from the gas phase, using a gas aggregation source for the Co nanoparticles and a molecular beam epitaxy (MBE) source for the Cr matrix material. Co K and Cr K edge extended x-ray absorption fine structure (EXAFS) experiments were performed in order to investigate atomic structure in the embedded nanoparticles and matrix respectively, while magnetism was investigated by means of a vibrating sample magnetometer. The atomic structure type of the Co nanoparticles is the same as that of the Cr matrix (bcc) although with a degree of disorder. The net Co moment per atom in the Co/Cr nanocomposite films is significantly reduced from the value for bulk Co, and decreases as the proportion of Co nanoparticles in the film is decreased; for the sample with the most dilute concentration of Co nanoparticles (4.9% by volume), the net Co moment was 0.25 μ B/atom. After field cooling to below 30 K all samples showed an exchange bias, which was largest for the most dilute sample. Both the structural and magnetic results point towards a degree of alloying at the nanoparticle/matrix interface, leading to a core/shell structure in the embedded nanoparticles consisting of an antiferromagnetic CoCr alloy shell surrounding a reduced ferromagnetic Co core.

  4. Artificial Atoms: from Quantum Physics to Applications

    International Nuclear Information System (INIS)

    2014-01-01

    The primary objective of this workshop is to survey the most recent advances of technologies enabling single atom- and artificial atom-based devices. These include the assembly of artificial molecular structures with magnetic dipole and optical interactions between engineered atoms embedded in solid-state lattices. The ability to control single atoms in diamond or similar solids under ambient operating conditions opens new perspectives for technologies based on nanoelectronics and nanophotonics. The scope of the workshop is extended towards the physics of strong coupling between atoms and radiation field modes. Beyond the traditional atom-cavity systems, artificial dipoles coupled to microwave radiation in circuit quantum electrodynamics is considered. All these technologies mutually influence each other in developing novel devices for sensing at the quantum level and for quantum information processing.

  5. DNCON2: improved protein contact prediction using two-level deep convolutional neural networks.

    Science.gov (United States)

    Adhikari, Badri; Hou, Jie; Cheng, Jianlin

    2018-05-01

    Significant improvements in the prediction of protein residue-residue contacts are observed in the recent years. These contacts, predicted using a variety of coevolution-based and machine learning methods, are the key contributors to the recent progress in ab initio protein structure prediction, as demonstrated in the recent CASP experiments. Continuing the development of new methods to reliably predict contact maps is essential to further improve ab initio structure prediction. In this paper we discuss DNCON2, an improved protein contact map predictor based on two-level deep convolutional neural networks. It consists of six convolutional neural networks-the first five predict contacts at 6, 7.5, 8, 8.5 and 10 Å distance thresholds, and the last one uses these five predictions as additional features to predict final contact maps. On the free-modeling datasets in CASP10, 11 and 12 experiments, DNCON2 achieves mean precisions of 35, 50 and 53.4%, respectively, higher than 30.6% by MetaPSICOV on CASP10 dataset, 34% by MetaPSICOV on CASP11 dataset and 46.3% by Raptor-X on CASP12 dataset, when top L/5 long-range contacts are evaluated. We attribute the improved performance of DNCON2 to the inclusion of short- and medium-range contacts into training, two-level approach to prediction, use of the state-of-the-art optimization and activation functions, and a novel deep learning architecture that allows each filter in a convolutional layer to access all the input features of a protein of arbitrary length. The web server of DNCON2 is at http://sysbio.rnet.missouri.edu/dncon2/ where training and testing datasets as well as the predictions for CASP10, 11 and 12 free-modeling datasets can also be downloaded. Its source code is available at https://github.com/multicom-toolbox/DNCON2/. chengji@missouri.edu. Supplementary data are available at Bioinformatics online.

  6. Spin Accumulation of Spinor Atoms in Optical Lattices

    International Nuclear Information System (INIS)

    Li Hong; Jiang Zhanfeng

    2007-01-01

    We obtain an effective spin correlation Hamiltonian describing the interaction of light with a two-level atom, then we investigate the classical trajectory of the two-level atom system by numerical integration of the Heisenberg equation of motion. Our results show that the spin accumulation is a very popular phenomenon as long as the spin character cannot be ignored in the Hamiltonian. We propose experimental protocol to observe this new phenomenon in further experiments.

  7. Atomic politics

    International Nuclear Information System (INIS)

    Skogmar, G.

    1979-01-01

    The authors basic point is that the military and civil sides of atomic energy cannot be separated. The general aim of the book is to analyze both the military and civil branches, and the interdependence between them, of American foreign policy in the atomic field. Atomic policy is seen as one of the most important imstruments of foreign policy which, in turn, is seen against the background of American imperialism in general. Firstly, the book investigates the most important means by which the United States has controlled the development in the nuclear field in other countries. These means include influencing the conditions of access to nuclear resources of various kinds, influencing the flow of technical-economic information and influencing international organizations and treaties bearing on atomic energy. The time period treated is 1945-1973. 1973 is chosen as the end-year of the study mainly because of the new conditions in the whole energy field initiated by the oil crisis in that year. The sources of the empirical work are mainly hearings before the Joint Committee on Atomic Energy of the U.S. Congress and legal material of various kinds. Secondly, the goals of the American policy are analyzed. The goals identified are armament effect, non-proliferation (horizontal), sales, and energy dependence. The relation between the main goals is discussed.The discussion is centered on the interdependence between the military and the civil aspects, conflict and coincidence of various goals, the relation between short-term and long-term goals, and the possibilities of using one goal as pretext for another. Thirdly, some causes of the changes in the atomic policy around 1953 and 1963 are identified. These are the strategic balance, the competitive situation, the capacity (of the American atomic productive apparatus), and the nuclear technological stage. The specific composition of these four factors at the two time-points can explain the changes of policy. (author)

  8. Embedded Linux projects using Yocto project cookbook

    CERN Document Server

    González, Alex

    2015-01-01

    If you are an embedded developer learning about embedded Linux with some experience with the Yocto project, this book is the ideal way to become proficient and broaden your knowledge with examples that are immediately applicable to your embedded developments. Experienced embedded Yocto developers will find new insight into working methodologies and ARM specific development competence.

  9. Adsorption of gas molecules on Cu impurities embedded monolayer MoS{sub 2}: A first- principles study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, B.; Li, C.Y. [Hubei Nuclear Solid Physics Key Laboratory, Department of Physics, Wuhan University, Wuhan 430072 (China); Liu, L.L. [Key Lab for Special Functional Materials of Ministry of Eduaction, Henan Province, Henan University, Kaifeng 475004 (China); Zhou, B.; Zhang, Q.K. [Hubei Nuclear Solid Physics Key Laboratory, Department of Physics, Wuhan University, Wuhan 430072 (China); Chen, Z.Q., E-mail: chenzq@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Department of Physics, Wuhan University, Wuhan 430072 (China); Tang, Z., E-mail: ztang@ee.ecnu.edu.cn [Key Laboratory of Polar Materials and Devices, Ministry of Education of China, East China Normal University, Shanghai 200241 (China)

    2016-09-30

    Highlights: • Embedded Cu atom is strongly constrained on the sulfur vacancy of monolayer MoS{sub 2}. • Transition-metal Cu atom can break the chemical inactivation of MoS{sub 2} surface. • MoS{sub 2}-Cu system is a promising for future application in gas molecules sensing. - Abstract: Adsorption of small gas molecules (O{sub 2}, NO, NO{sub 2} and NH{sub 3}) on transition-metal Cu atom embedded monolayer MoS{sub 2} was investigated by first-principles calculations based on the density-functional theory (DFT). The embedded Cu atom is strongly constrained on the sulfur vacancy of monolayer MoS{sub 2} with a high diffusion barrier. The stable adsorption geometry, charge transfer and electronic structures of these gas molecules on monolayer MoS{sub 2} embedded with transition-metal Cu atom are discussed in detail. It is found that the monolayer MoS{sub 2} with embedded Cu atom can effectively capture these gas molecules with high adsorption energy. The NH{sub 3} molecule acts as electron donor after adsorption, which is different from the other gas molecules (O{sub 2}, NO, and NO{sub 2}). The results suggest that MoS{sub 2}-Cu system may be promising for future applications in gas molecules sensing and catalysis, which is similar to those of the transition-metal embedded graphene.

  10. Trusted computing for embedded systems

    CERN Document Server

    Soudris, Dimitrios; Anagnostopoulos, Iraklis

    2015-01-01

    This book describes the state-of-the-art in trusted computing for embedded systems. It shows how a variety of security and trusted computing problems are addressed currently and what solutions are expected to emerge in the coming years. The discussion focuses on attacks aimed at hardware and software for embedded systems, and the authors describe specific solutions to create security features. Case studies are used to present new techniques designed as industrial security solutions. Coverage includes development of tamper resistant hardware and firmware mechanisms for lightweight embedded devices, as well as those serving as security anchors for embedded platforms required by applications such as smart power grids, smart networked and home appliances, environmental and infrastructure sensor networks, etc. ·         Enables readers to address a variety of security threats to embedded hardware and software; ·         Describes design of secure wireless sensor networks, to address secure authen...

  11. Spectral density of Cooper pairs in two level quantum dot–superconductors Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Dhyani, A., E-mail: archana.d2003@gmail.com [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Rawat, P.S. [Department of Nuclear Science and Technology, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Tewari, B.S., E-mail: bstewari@ddn.upes.ac.in [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India)

    2016-09-15

    Highlights: • The present work deals with the study of the electronic spectral density of electron pairs and its effect in charge transport in superconductor-quantum dot-superconductor junctions. • The charge transfer across such junctions can be controlled by changing the positions of the dot level. • The Josephson supercurrent can also be tuned by controlling the position of quantum dot energy levels. - Abstract: In the present paper, we report the role of quantum dot energy levels on the electronic spectral density for a two level quantum dot coupled to s-wave superconducting leads. The theoretical arguments in this work are based on the Anderson model so that it necessarily includes dot energies, single particle tunneling and superconducting order parameter for BCS superconductors. The expression for single particle spectral function is obtained by using the Green's function equation of motion technique. On the basis of numerical computation of spectral function of superconducting leads, it has been found that the charge transfer across such junctions can be controlled by the positions and availability of the dot levels.

  12. A distributed monitoring system for photovoltaic arrays based on a two-level wireless sensor network

    Science.gov (United States)

    Su, F. P.; Chen, Z. C.; Zhou, H. F.; Wu, L. J.; Lin, P. J.; Cheng, S. Y.; Li, Y. F.

    2017-11-01

    In this paper, a distributed on-line monitoring system based on a two-level wireless sensor network (WSN) is proposed for real time status monitoring of photovoltaic (PV) arrays to support the fine management and maintenance of PV power plants. The system includes the sensing nodes installed on PV modules (PVM), sensing and routing nodes installed on combiner boxes of PV sub-arrays (PVA), a sink node and a data management centre (DMC) running on a host computer. The first level WSN is implemented by the low-cost wireless transceiver nRF24L01, and it is used to achieve single hop communication between the PVM nodes and their corresponding PVA nodes. The second level WSN is realized by the CC2530 based ZigBee network for multi-hop communication among PVA nodes and the sink node. The PVM nodes are used to monitor the PVM working voltage and backplane temperature, and they send the acquired data to their PVA node via the nRF24L01 based first level WSN. The PVA nodes are used to monitor the array voltage, PV string current and environment irradiance, and they send the acquired and received data to the DMC via the ZigBee based second level WSN. The DMC is designed using the MATLAB GUIDE and MySQL database. Laboratory experiment results show that the system can effectively acquire, display, store and manage the operating and environment parameters of PVA in real time.

  13. Domain decomposition method of stochastic PDEs: a two-level scalable preconditioner

    International Nuclear Information System (INIS)

    Subber, Waad; Sarkar, Abhijit

    2012-01-01

    For uncertainty quantification in many practical engineering problems, the stochastic finite element method (SFEM) may be computationally challenging. In SFEM, the size of the algebraic linear system grows rapidly with the spatial mesh resolution and the order of the stochastic dimension. In this paper, we describe a non-overlapping domain decomposition method, namely the iterative substructuring method to tackle the large-scale linear system arising in the SFEM. The SFEM is based on domain decomposition in the geometric space and a polynomial chaos expansion in the probabilistic space. In particular, a two-level scalable preconditioner is proposed for the iterative solver of the interface problem for the stochastic systems. The preconditioner is equipped with a coarse problem which globally connects the subdomains both in the geometric and probabilistic spaces via their corner nodes. This coarse problem propagates the information quickly across the subdomains leading to a scalable preconditioner. For numerical illustrations, a two-dimensional stochastic elliptic partial differential equation (SPDE) with spatially varying non-Gaussian random coefficients is considered. The numerical scalability of the the preconditioner is investigated with respect to the mesh size, subdomain size, fixed problem size per subdomain and order of polynomial chaos expansion. The numerical experiments are performed on a Linux cluster using MPI and PETSc parallel libraries.

  14. Vorticity, backscatter and counter-gradient transport predictions using two-level simulation of turbulent flows

    Science.gov (United States)

    Ranjan, R.; Menon, S.

    2018-04-01

    The two-level simulation (TLS) method evolves both the large-and the small-scale fields in a two-scale approach and has shown good predictive capabilities in both isotropic and wall-bounded high Reynolds number (Re) turbulent flows in the past. Sensitivity and ability of this modelling approach to predict fundamental features (such as backscatter, counter-gradient turbulent transport, small-scale vorticity, etc.) seen in high Re turbulent flows is assessed here by using two direct numerical simulation (DNS) datasets corresponding to a forced isotropic turbulence at Taylor's microscale-based Reynolds number Reλ ≈ 433 and a fully developed turbulent flow in a periodic channel at friction Reynolds number Reτ ≈ 1000. It is shown that TLS captures the dynamics of local co-/counter-gradient transport and backscatter at the requisite scales of interest. These observations are further confirmed through a posteriori investigation of the flow in a periodic channel at Reτ = 2000. The results reveal that the TLS method can capture both the large- and the small-scale flow physics in a consistent manner, and at a reduced overall cost when compared to the estimated DNS or wall-resolved LES cost.

  15. Robust Methods for Moderation Analysis with a Two-Level Regression Model.

    Science.gov (United States)

    Yang, Miao; Yuan, Ke-Hai

    2016-01-01

    Moderation analysis has many applications in social sciences. Most widely used estimation methods for moderation analysis assume that errors are normally distributed and homoscedastic. When these assumptions are not met, the results from a classical moderation analysis can be misleading. For more reliable moderation analysis, this article proposes two robust methods with a two-level regression model when the predictors do not contain measurement error. One method is based on maximum likelihood with Student's t distribution and the other is based on M-estimators with Huber-type weights. An algorithm for obtaining the robust estimators is developed. Consistent estimates of standard errors of the robust estimators are provided. The robust approaches are compared against normal-distribution-based maximum likelihood (NML) with respect to power and accuracy of parameter estimates through a simulation study. Results show that the robust approaches outperform NML under various distributional conditions. Application of the robust methods is illustrated through a real data example. An R program is developed and documented to facilitate the application of the robust methods.

  16. Multilevel Converter by Cascading Two-Level Three-Phase Voltage Source Converter

    Directory of Open Access Journals (Sweden)

    Abdullrahman A. Al-Shamma’a

    2018-04-01

    Full Text Available This paper proposes a topology using isolated, cascaded multilevel voltage source converters (VSCs and employing two-winding magnetic elements for high-power applications. The proposed topology synthesizes 6 two-level, three-phase VSCs, so the power capability of the presented converter is six times the capability of each VSC module. The characteristics of the proposed topology are demonstrated through analyzing its current relationships, voltage relationships and power capability in detail. The power rating is equally shared among the VSC modules without the need for a sharing algorithm; thus, the converter operates as a single three-phase VSC. The comparative analysis with classical neutral-point clamped, flying capacitor and cascaded H-bridge exhibits the superior features of fewer insulated gate bipolar transistors (IGBTs, capacitor requirement and fewer diodes. To validate the theoretical performance of the proposed converter, it is simulated in a MATLAB/Simulink environment and the results are experimentally demonstrated using a laboratory prototype.

  17. Acoustic interactions between inversion symmetric and asymmetric two-level systems

    International Nuclear Information System (INIS)

    Churkin, A; Schechter, M; Barash, D

    2014-01-01

    Amorphous solids, as well as many disordered lattices, display remarkable universality in their low temperature acoustic properties. This universality is attributed to the attenuation of phonons by tunneling two-level systems (TLSs), facilitated by the interaction of the TLSs with the phonon field. TLS-phonon interaction also mediates effective TLS–TLS interactions, which dictates the existence of a glassy phase and its low energy properties. Here we consider KBr:CN, the archetypal disordered lattice showing universality. We calculate numerically, using conjugate gradients method, the effective TLS–TLS interactions for inversion symmetric (CN flips) and asymmetric (CN rotations) TLSs, in the absence and presence of disorder, in two and three dimensions. The observed dependence of the magnitude and spatial power law of the interaction on TLS symmetry, and its change with disorder, characterizes TLS–TLS interactions in disordered lattices in both extreme and moderate dilutions. Our results are in good agreement with the two-TLS model, recently introduced to explain long-standing questions regarding the quantitative universality of phonon attenuation and the energy scale of ≈1–3 K below which universality is observed. (paper)

  18. Generalized Heine–Stieltjes and Van Vleck polynomials associated with two-level, integrable BCS models

    International Nuclear Information System (INIS)

    Marquette, Ian; Links, Jon

    2012-01-01

    We study the Bethe ansatz/ordinary differential equation (BA/ODE) correspondence for Bethe ansatz equations that belong to a certain class of coupled, nonlinear, algebraic equations. Through this approach we numerically obtain the generalized Heine–Stieltjes and Van Vleck polynomials in the degenerate, two-level limit for four cases of integrable Bardeen–Cooper–Schrieffer (BCS) pairing models. These are the s-wave pairing model, the p + ip-wave pairing model, the p + ip pairing model coupled to a bosonic molecular pair degree of freedom, and a newly introduced extended d + id-wave pairing model with additional interactions. The zeros of the generalized Heine–Stieltjes polynomials provide solutions of the corresponding Bethe ansatz equations. We compare the roots of the ground states with curves obtained from the solution of a singular integral equation approximation, which allows for a characterization of ground-state phases in these systems. Our techniques also permit the computation of the roots of the excited states. These results illustrate how the BA/ODE correspondence can be used to provide new numerical methods to study a variety of integrable systems. (paper)

  19. Quasiparticle-induced decoherence of microscopic two-level-systems in superconducting qubits

    Energy Technology Data Exchange (ETDEWEB)

    Bilmes, Alexander; Lisenfeld, Juergen; Zanker, Sebastian; Weiss, Georg; Ustinov, Alexey V. [PHI, KIT, Karlsruhe (Germany); Marthaler, Michael; Schoen, Gerd [TFP, KIT, Karlsruhe (Germany)

    2016-07-01

    Parasitic Two-Level-Systems (TLS) are one of the main sources of decoherence in superconducting nano-scale devices such as SQUIDs, resonators and quantum bits (qubits), although the TLS' microscopic nature remains unclear. We use a superconducting phase qubit to detect TLS contained within the tunnel barrier of the qubit's Al/AlOx/Al Josephson junction. If the TLS transition frequency lies within the 6-10 GHz range, we can coherently drive it by resonant microwave pulses and access its quantum state by utilizing the strong coupling to the qubit. Our previous measurements of TLS coherence in dependence of the temperature indicate that quasiparticles (QPs), which diffuse from the superconducting Al electrodes into the oxide layer, may give rise to TLS energy loss and dephasing. Here, we probe the TLS-QP interaction using a reliable method of in-situ QP injection via an on-chip dc-SQUID that is pulse-biased beyond its switching current. The QP density is calibrated by measuring associated characteristic changes to the qubit's energy relaxation rate. We will present experimental data which show the QP-induced TLS decoherence in good agreement to theoretical predictions.

  20. Two-Level Evaluation on Sensor Interoperability of Features in Fingerprint Image Segmentation

    Directory of Open Access Journals (Sweden)

    Ya-Shuo Li

    2012-03-01

    Full Text Available Features used in fingerprint segmentation significantly affect the segmentation performance. Various features exhibit different discriminating abilities on fingerprint images derived from different sensors. One feature which has better discriminating ability on images derived from a certain sensor may not adapt to segment images derived from other sensors. This degrades the segmentation performance. This paper empirically analyzes the sensor interoperability problem of segmentation feature, which refers to the feature’s ability to adapt to the raw fingerprints captured by different sensors. To address this issue, this paper presents a two-level feature evaluation method, including the first level feature evaluation based on segmentation error rate and the second level feature evaluation based on decision tree. The proposed method is performed on a number of fingerprint databases which are obtained from various sensors. Experimental results show that the proposed method can effectively evaluate the sensor interoperability of features, and the features with good evaluation results acquire better segmentation accuracies of images originating from different sensors.

  1. Amplification without inversion, fast light and optical bistability in a duplicated two-level system

    International Nuclear Information System (INIS)

    Ebrahimi Zohravi, Lida; Vafafard, Azar; Mahmoudi, Mohammad

    2014-01-01

    The optical properties of a weak probe field in a duplicated two-level system are investigated in multi-photon resonance (MPR) condition and beyond it. It is shown that by changing the relative phase of applied fields, the absorption switches to the amplification without inversion in MPR condition. By applying the Floquet decomposition to the equations of motion beyond MPR condition, it is shown that the phase-dependent behavior is valid only in MPR condition. Moreover, it is demonstrated that the group velocity of light pulse can be controlled by the intensity of the applied fields and the gain-assisted superluminal light propagation (fast light) is obtained in this system. In addition, the optical bistability (OB) behavior of the system is studied beyond MPR condition. We apply an indirect incoherent pumping field to the system and it is found that the group velocity and OB behavior of the system can be controlled by the incoherent pumping rate. - Highlights: • We studied the optical properties of DTL system under MPR condition and beyond it. • By changing the relative phase, the absorption switches to the amplification without inversion in MPR condition. • The gain-assisted superluminal light propagation (fast light) is obtained in this system. • The optical bistability (OB) behavior of the system is studied beyond MPR condition. • The incoherent pumping rate has a major role in controlling the group velocity and OB behavior of the system

  2. Automatic QRS complex detection using two-level convolutional neural network.

    Science.gov (United States)

    Xiang, Yande; Lin, Zhitao; Meng, Jianyi

    2018-01-29

    The QRS complex is the most noticeable feature in the electrocardiogram (ECG) signal, therefore, its detection is critical for ECG signal analysis. The existing detection methods largely depend on hand-crafted manual features and parameters, which may introduce significant computational complexity, especially in the transform domains. In addition, fixed features and parameters are not suitable for detecting various kinds of QRS complexes under different circumstances. In this study, based on 1-D convolutional neural network (CNN), an accurate method for QRS complex detection is proposed. The CNN consists of object-level and part-level CNNs for extracting different grained ECG morphological features automatically. All the extracted morphological features are used by multi-layer perceptron (MLP) for QRS complex detection. Additionally, a simple ECG signal preprocessing technique which only contains difference operation in temporal domain is adopted. Based on the MIT-BIH arrhythmia (MIT-BIH-AR) database, the proposed detection method achieves overall sensitivity Sen = 99.77%, positive predictivity rate PPR = 99.91%, and detection error rate DER = 0.32%. In addition, the performance variation is performed according to different signal-to-noise ratio (SNR) values. An automatic QRS detection method using two-level 1-D CNN and simple signal preprocessing technique is proposed for QRS complex detection. Compared with the state-of-the-art QRS complex detection approaches, experimental results show that the proposed method acquires comparable accuracy.

  3. Two-level image authentication by two-step phase-shifting interferometry and compressive sensing

    Science.gov (United States)

    Zhang, Xue; Meng, Xiangfeng; Yin, Yongkai; Yang, Xiulun; Wang, Yurong; Li, Xianye; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2018-01-01

    A two-level image authentication method is proposed; the method is based on two-step phase-shifting interferometry, double random phase encoding, and compressive sensing (CS) theory, by which the certification image can be encoded into two interferograms. Through discrete wavelet transform (DWT), sparseness processing, Arnold transform, and data compression, two compressed signals can be generated and delivered to two different participants of the authentication system. Only the participant who possesses the first compressed signal attempts to pass the low-level authentication. The application of Orthogonal Match Pursuit CS algorithm reconstruction, inverse Arnold transform, inverse DWT, two-step phase-shifting wavefront reconstruction, and inverse Fresnel transform can result in the output of a remarkable peak in the central location of the nonlinear correlation coefficient distributions of the recovered image and the standard certification image. Then, the other participant, who possesses the second compressed signal, is authorized to carry out the high-level authentication. Therefore, both compressed signals are collected to reconstruct the original meaningful certification image with a high correlation coefficient. Theoretical analysis and numerical simulations verify the feasibility of the proposed method.

  4. Dynamics of a quantum two-level system under the action of phase-diffusion field

    Energy Technology Data Exchange (ETDEWEB)

    Sobakinskaya, E.A. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Pankratov, A.L., E-mail: alp@ipm.sci-nnov.ru [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Vaks, V.L. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation)

    2012-01-09

    We study a behavior of quantum two-level system, interacting with noisy phase-diffusion field. The dynamics is shown to split into two regimes, determined by the coherence time of the phase-diffusion field. For both regimes we present a model of quantum system behavior and discuss possible applications of the obtained effect for spectroscopy. In particular, the obtained analytical formula for the macroscopic polarization demonstrates that the phase-diffusion field does not affect the absorption line shape, which opens up an intriguing possibility of noisy spectroscopy, based on broadband sources with Lorentzian line shape. -- Highlights: ► We study dynamics of quantum system interacting with noisy phase-diffusion field. ► At short times the phase-diffusion field induces polarization in the quantum system. ► At long times the noise leads to polarization decay and heating of a quantum system. ► Simple model of interaction is derived. ► Application of the described effects for spectroscopy is discussed.

  5. Injury patterns of child abuse: Experience of two Level 1 pediatric trauma centers.

    Science.gov (United States)

    Yu, Yangyang R; DeMello, Annalyn S; Greeley, Christopher S; Cox, Charles S; Naik-Mathuria, Bindi J; Wesson, David E

    2018-05-01

    This study examines non-accidental trauma (NAT) fatalities as a percentage of all injury fatalities and identifies injury patterns in NAT admissions to two level 1 pediatric trauma centers. We reviewed all children (<5years old) treated for NAT from 2011 to 2015. Patient demographics, injury sites, and survival were obtained from both institutional trauma registries. Of 4623 trauma admissions, 557 (12%) were due to NAT. However, 43 (46%) of 93 overall trauma fatalities were due to NAT. Head injuries were the most common injuries sustained (60%) and led to the greatest increased risk of death (RR 5.1, 95% CI 2.0-12.7). Less common injuries that increased the risk of death were facial injuries (14%, RR 2.9, 95% CI 1.6-5.3), abdominal injuries (8%, RR 2.8, 95% CI 1.4-5.6), and spinal injuries (3%, RR 3.9, 95% CI 1.8-8.8). Although 76% of head injuries occurred in infants <1year, children ages 1-4years old with head injuries had a significantly higher case fatality rate (27% vs. 6%, p<0.001). Child abuse accounts for a large proportion of trauma fatalities in children under 5years of age. Intracranial injuries are common in child abuse and increase the risk of death substantially. Preventing NAT in infants and young children should be a public health priority. Retrospective Review. II. Copyright © 2018. Published by Elsevier Inc.

  6. Risk Analysis of a Two-Level Supply Chain Subject to Misplaced Inventory

    Directory of Open Access Journals (Sweden)

    Lijing Zhu

    2017-06-01

    Full Text Available Misplaced inventory is prevalent in retail stores and may lead to the overall poor performance of the supply chain. We explore the impact of misplaced inventory on a two-level supply chain, which consists of a risk-neutral supplier and a risk-averse retailer. The supplier decides the wholesale price to maximize her profit, whereas the retailer decides the order quantity to maximize his utility. Under the Conditional Value-at-Risk (CVaR criterion, we formulate the problem as a Stackelberg game model and obtain the equilibrium solutions in three cases: (i information asymmetry about inventory errors exists; (ii the retailer shares information about inventory errors with the supplier; and (iii in order to reduce misplaced inventory, the supply chain deploys Radio-Frequency Identification (RFID technology. The benefits of information sharing and RFID implementation are explored. A revenue and cost sharing contract is proposed to coordinate the supply chain and to allocate the cost savings from RFID implementation among supply chain participants. Finally, we provide managerial insights for risk-averse decision makers that are considering investing in the RFID technology.

  7. Testing a Quantum Heat Pump with a Two-Level Spin

    Directory of Open Access Journals (Sweden)

    Luis A. Correa

    2016-04-01

    Full Text Available Once in its non-equilibrium steady state, a nanoscale system coupled to several heat baths may be thought of as a “quantum heat pump”. Depending on the direction of its stationary heat flows, it may function as, e.g., a refrigerator or a heat transformer. These continuous heat devices can be arbitrarily complex multipartite systems, and yet, their working principle is always the same: they are made up of several elementary three-level stages operating in parallel. As a result, it is possible to devise external “black-box” testing strategies to learn about their functionality and performance regardless of any internal details. In particular, one such heat pump can be tested by coupling a two-level spin to one of its “contact transitions”. The steady state of this external probe contains information about the presence of heat leaks and internal dissipation in the device and, also, about the direction of its steady-state heat currents. Provided that the irreversibility of the heat pump is low, one can further estimate its coefficient of performance. These techniques may find applications in the emerging field of quantum thermal engineering, as they facilitate the diagnosis and design optimization of complex thermodynamic cycles.

  8. Two level undercut-profile substrate-based filamentary coated conductors produced using metal organic chemical vapor deposition

    DEFF Research Database (Denmark)

    Insinga, Andrea R.; Sundaram, Aarthi; Hazelton, Drew W.

    2018-01-01

    The two level undercut-profile substrate (2LUPS) has been introduced as a concept for subdividing rare-earth-Ba$_{2}$Cu$_{3}$O$_{7}$ (REBCO) coated conductors (CC) into narrow filaments which reduces the AC losses and improves field stability for DC magnets. The 2LUPS consists of two levels...

  9. Atomic secrecy

    International Nuclear Information System (INIS)

    Sweet, W.

    1979-01-01

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  10. Geometric phase for a two-level system in photonic band gab crystal

    Science.gov (United States)

    Berrada, K.

    2018-05-01

    In this work, we investigate the geometric phase (GP) for a qubit system coupled to its own anisotropic and isotropic photonic band gap (PBG) crystal environment without Born or Markovian approximation. The qubit frequency affects the GP of the qubit directly through the effect of the PBG environment. The results show the deviation of the GP depends on the detuning parameter and this deviation will be large for relatively large detuning of atom frequency inside the gap with respect to the photonic band edge. Whereas for detunings outside the gap, the GP of the qubit changes abruptly to zero, exhibiting collapse phenomenon of the GP. Moreover, we find that the GP in the isotropic PBG photonic crystal is more robust than that in the anisotropic PBG under the same condition. Finally, we explore the relationship between the variation of the GP and population in terms of the physical parameters.

  11. Fe and Co nanostructures embedded into the Cu(100) surface: Self-Organization and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Kolesnikov, S. V., E-mail: kolesnikov@physics.msu.ru; Klavsyuk, A. L.; Saletsky, A. M. [Moscow State University, Faculty of Physics (Russian Federation)

    2015-10-15

    The self-organization and magnetic properties of small iron and cobalt nanostructures embedded into the first layer of a Cu(100) surface are investigated using the self-learning kinetic Monte Carlo method and density functional theory. The similarities and differences between the Fe/Cu(100) and the Co/Cu(100) are underlined. The time evolution of magnetic properties of a copper monolayer with embedded magnetic atoms at 380 K is discussed.

  12. Resonance fluorescence based two- and three-dimensional atom localization

    Science.gov (United States)

    Wahab, Abdul; Rahmatullah; Qamar, Sajid

    2016-06-01

    Two- and three-dimensional atom localization in a two-level atom-field system via resonance fluorescence is suggested. For the two-dimensional localization, the atom interacts with two orthogonal standing-wave fields, whereas for the three-dimensional atom localization, the atom interacts with three orthogonal standing-wave fields. The effect of the detuning and phase shifts associated with the corresponding standing-wave fields is investigated. A precision enhancement in position measurement of the single atom can be noticed via the control of the detuning and phase shifts.

  13. Design Methodologies for Secure Embedded Systems

    CERN Document Server

    Biedermann, Alexander

    2011-01-01

    Embedded systems have been almost invisibly pervading our daily lives for several decades. They facilitate smooth operations in avionics, automotive electronics, or telecommunication. New problems arise by the increasing employment, interconnection, and communication of embedded systems in heterogeneous environments: How secure are these embedded systems against attacks or breakdowns? Therefore, how can embedded systems be designed to be more secure? And how can embedded systems autonomically react to threats? Facing these questions, Sorin A. Huss is significantly involved in the exploration o

  14. Certifiable Java for Embedded Systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Dalsgaard, Andreas Engelbredt; Hansen, Rene Rydhof

    2014-01-01

    The Certifiable Java for Embedded Systems (CJ4ES) project aimed to develop a prototype development environment and platform for safety-critical software for embedded applications. There are three core constituents: A profile of the Java programming language that is tailored for safety......-critical applications, a predictable Java processor built with FPGA technology, and an Eclipse based application development environment that binds the profile and the platform together and provides analyses that help to provide evidence that can be used as part of a safety case. This paper summarizes key contributions...

  15. Morphware - Fremtidens Embedded System Platform

    DEFF Research Database (Denmark)

    Madsen, Jan

    2006-01-01

    FPGA'er bliver i stigende grad brugt som komponenter i embedded systemer. Faldende priser, større kapacitet og en større felksibilitet har gjort FPGA'en til en attraktiv og konkurrencedygtig teknologi der tillader en stadig stigende grad af system integration, hvor traditionel hardware og software...... kombineres og rekonfigureres. Muligheden for at rekonfigurere systemet, og specielt rekonfigurerer det medens det kører, giver nogle helt nye muligheder for at designe og programmere embedded systemer. Dette foredrag vil give et indblik i disse nye og fremtidige muligheder....

  16. Implementation of an embedded computer

    OpenAIRE

    Pikl, Bojan

    2011-01-01

    The goal of this thesis is to describe a production of an embedded computer. The thesis describes development and production of an embedded computer for the medical diode laser DL30 that is being developed in Robomed d.o.o.. The first part of the thesis describes the choice of hardware devices. I mostly describe the technologies that one can buy on the market. Moreover for every part of the computer installed and developed there is an argument why we selected that exact part. The second part ...

  17. Homogeneous Spaces and Equivariant Embeddings

    CERN Document Server

    Timashev, DA

    2011-01-01

    Homogeneous spaces of linear algebraic groups lie at the crossroads of algebraic geometry, theory of algebraic groups, classical projective and enumerative geometry, harmonic analysis, and representation theory. By standard reasons of algebraic geometry, in order to solve various problems on a homogeneous space it is natural and helpful to compactify it keeping track of the group action, i.e. to consider equivariant completions or, more generally, open embeddings of a given homogeneous space. Such equivariant embeddings are the subject of this book. We focus on classification of equivariant em

  18. A Foundation for Embedded Languages

    DEFF Research Database (Denmark)

    Rhiger, Morten

    2003-01-01

    Recent work on embedding object languages into Haskell use "phantom types" (i.e., parameterized types whose parameter does not occur on the right-hand side of the type definition) to ensure that the embedded object-language terms are simply typed. But is it a safe assumption that only simply......-typed terms can be represented in Haskell using phantom types? And conversely, can all simply-typed terms be represented in Haskell under the restrictions imposed by phantom types? In this article we investigate the conditions under which these assumptions are true: We show that these questions can...

  19. A Foundation for Embedded Languages

    DEFF Research Database (Denmark)

    Rhiger, Morten

    2002-01-01

    Recent work on embedding object languages into Haskell use "phantom types" (i.e., parameterized types whose parameter does not occur on the right-hand side of the type definition) to ensure that the embedded object-language terms are simply typed. But is it a safe assumption that only simply......-typed terms can be represented in Haskell using phantom types? And conversely, can all simply-typed terms be represented in Haskell under the restrictions imposed by phantom types? In this article we investigate the conditions under which these assumptions are true: We show that these questions can...

  20. Antimatter atoms

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    In january 1996, CERN broadcasted the information of the creation of nine anti-hydrogen atoms, observed through disintegration products. The experimental facility was CERN LEAR ring. An antiproton beam scattered a xenon jet, and the resulting antimatter was first selected by its insensitivity to beam bending magnets. Their disintegration was detected in thin NaI detectors, in which the anti-atoms are at once deprived from their positron. Then, magnetic and time-of-flight spectrometers are used. (D.L.)

  1. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  2. Lambda-Based Data Processing Architecture for Two-Level Load Forecasting in Residential Buildings

    Directory of Open Access Journals (Sweden)

    Gde Dharma Nugraha

    2018-03-01

    Full Text Available Building energy management systems (BEMS have been intensively used to manage the electricity consumption of residential buildings more efficiently. However, the dynamic behavior of the occupants introduces uncertainty problems that affect the performance of the BEMS. To address this uncertainty problem, the BEMS may implement load forecasting as one of the BEMS modules. Load forecasting utilizes historical load data to compute model predictions for a specific time in the future. Recently, smart meters have been introduced to collect electricity consumption data. Smart meters not only capture aggregation data, but also individual data that is more frequently close to real-time. The processing of both smart meter data types for load forecasting can enhance the performance of the BEMS when confronted with uncertainty problems. The collection of smart meter data can be processed using a batch approach for short-term load forecasting, while the real-time smart meter data can be processed for very short-term load forecasting, which adjusts the short-term load forecasting to adapt to the dynamic behavior of the occupants. This approach requires different data processing techniques for aggregation and individual of smart meter data. In this paper, we propose Lambda-based data processing architecture to process the different types of smart meter data and implement the two-level load forecasting approach, which combines short-term and very short-term load forecasting techniques on top of our proposed data processing architecture. The proposed approach is expected to enhance the BEMS to address the uncertainty problem in order to process data in less time. Our experiment showed that the proposed approaches improved the accuracy by 7% compared to a typical BEMS with only one load forecasting technique, and had the lowest computation time when processing the smart meter data.

  3. A two level mutation-selection model of cultural evolution and diversity.

    Science.gov (United States)

    Salazar-Ciudad, Isaac

    2010-11-21

    Cultural evolution is a complex process that can happen at several levels. At the level of individuals in a population, each human bears a set of cultural traits that he or she can transmit to its offspring (vertical transmission) or to other members of his or her society (horizontal transmission). The relative frequency of a cultural trait in a population or society can thus increase or decrease with the relative reproductive success of its bearers (individual's level) or the relative success of transmission (called the idea's level). This article presents a mathematical model on the interplay between these two levels. The first aim of this article is to explore when cultural evolution is driven by the idea's level, when it is driven by the individual's level and when it is driven by both. These three possibilities are explored in relation to (a) the amount of interchange of cultural traits between individuals, (b) the selective pressure acting on individuals, (c) the rate of production of new cultural traits, (d) the individual's capacity to remember cultural traits and to the population size. The aim is to explore the conditions in which cultural evolution does not lead to a better adaptation of individuals to the environment. This is to contrast the spread of fitness-enhancing ideas, which make individual bearers better adapted to the environment, to the spread of "selfish" ideas, which spread well simply because they are easy to remember but do not help their individual bearers (and may even hurt them). At the same time this article explores in which conditions the adaptation of individuals is maximal. The second aim is to explore how these factors affect cultural diversity, or the amount of different cultural traits in a population. This study suggests that a larger interchange of cultural traits between populations could lead to cultural evolution not improving the adaptation of individuals to their environment and to a decrease of cultural diversity

  4. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  5. Coexistence of photonic and atomic Bose-Einstein condensates in ideal atomic gases

    Directory of Open Access Journals (Sweden)

    N. Boichenko

    2015-12-01

    Full Text Available We have studied conditions of photon Bose-Einstein condensate formation that is in thermodynamic equilibrium with ideal gas of two-level Bose atoms below the degeneracy temperature. Equations describing thermodynamic equilibrium in the system were formulated; critical temperatures and densities of photonic and atomic gas subsystems were obtained analytically. Coexistence conditions of these photonic and atomic Bose-Einstein condensates were found. There was predicted the possibility of an abrupt type of photon condensation in the presence of Bose condensate of ground-state atoms: it was shown that the slightest decrease of the temperature could cause a significant gathering of photons in the condensate. This case could be treated as a simple model of the situation known as "stopped light" in cold atomic gas. We also showed how population inversion of atomic levels can be created by lowering the temperature. The latter situation looks promising for light accumulation in atomic vapor at very low temperatures.

  6. Atoms stories

    International Nuclear Information System (INIS)

    Radvanyi, P.; Bordry, M.

    1988-01-01

    Physicists from different countries told each evening during one learning week, to an audience of young people, some great discoveries in evoking the difficulties and problems to which the researchers were confronted. From Antiquity to a more recent history, it is a succession of atoms stories. (N.C.)

  7. Atomic physics

    International Nuclear Information System (INIS)

    Held, B.

    1991-01-01

    This general book describes the change from classical physics to quantum physics. The first part presents atom evolution since antiquity and introduces fundamental quantities and elements of relativity. Experiments which have contributed to the evolution of knowledge on matter are analyzed in the second part. Applications of wave mechanics to the study of matter properties are presented in the third part [fr

  8. Quantum chaos of the 2-level atom

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R; Hoehnerbach, M [Essen Univ. (Germany, F.R.). Fachbereich Physik

    1984-01-01

    Recent work on the two-level atom coupled to a single mode of the electromagnetic field is reviewed from the point of view of 'quantum chaos', defined as the quantum behavior of a dynamical system which is non-integrable in the classical limit. Spectral properties and the dynamics of occupation probabilities including their revivals are obtained without making the rotating wave approximation.

  9. Embedding Sensors During Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Sbriglia, Lexey Raylene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-10

    This PowerPoint presentation had the following headings: Fused deposition modeling (FDM); Open source 3D printing; Objectives; Vibration analysis; Equipment; Design; Material choices; Failure causes, such as tension, bubbling; Potential solutions; Simulations; Embedding the sensors; LabView programming; Alternate data acquisition; Problem and proposed solution; and, Conclusions

  10. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gao, F.

    2008-01-01

    -voltage oscillations to the system. Therefore, Z-source inverters are in effect safer and less complex, and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family of embedded EZ...

  11. Software for Embedded Control Systems

    NARCIS (Netherlands)

    Broenink, Johannes F.; Hilderink, G.H.; Jovanovic, D.S.

    2001-01-01

    The research of our team deals with the realization of control schemes on digital computers. As such the emphasis is on embedded control software implementation. Applications are in the field of mechatronic devices, using a mechatronic design approach (the integrated and optimal design of a

  12. Two levels decision system for efficient planning and implementation of bioenergy production

    International Nuclear Information System (INIS)

    Ayoub, Nasser; Martins, Ricardo; Wang, Kefeng; Seki, Hiroya; Naka, Yuji

    2007-01-01

    When planning bioenergy production from biomass, planners should take into account each and every stakeholder along the biomass supply chains, e.g. biomass resources suppliers, transportation, conversion and electricity suppliers. Also, the planners have to consider social concerns, environmental and economical impacts related with establishing the biomass systems and the specific difficulties of each country. To overcome these problems in a sustainable manner, a robust decision support system is required. For that purpose, a two levels general Bioenergy Decision System (gBEDS) for bioenergy production planning and implementation was developed. The core part of the gBEDS is the information base, which includes the basic bioenergy information and the detailed decision information. Basic bioenergy information include, for instance, the geographical information system (GIS) database, the biomass materials' database, the biomass logistic database and the biomass conversion database. The detailed decision information considers the parameters' values database with their default values and the variables database, values obtained by simulation and optimization. It also includes a scenario database, which is used for demonstration to new users and also for case based reasoning by planners and executers. Based on the information base, the following modules are included to support decision making: the simulation module with graph interface based on the unit process (UP) definition and the genetic algorithms (GAs) methods for optimal decisions and the Matlab module for applying data mining methods (fuzzy C-means clustering and decision trees) to the biomass collection points, to define the location of storage and bioenergy conversion plants based on the simulation and optimization model developed of the whole life cycle of bioenergy generation. Furthermore, Matlab is used to set up a calculation model with crucial biomass planning parameters (e.g. costs, CO 2 emissions), over

  13. Embedded, everywhere: a research agenda for networked systems of embedded computers

    National Research Council Canada - National Science Library

    Committee on Networked Systems of Embedded Computers; National Research Council Staff; Division on Engineering and Physical Sciences; Computer Science and Telecommunications Board; National Academy of Sciences

    2001-01-01

    .... Embedded, Everywhere explores the potential of networked systems of embedded computers and the research challenges arising from embedding computation and communications technology into a wide variety of applicationsâ...

  14. The off-resonant aspects of decoherence and a critique of the two-level approximation

    International Nuclear Information System (INIS)

    Savran, Kerim; Hakioglu, T; Mese, E; Sevincli, Haldun

    2006-01-01

    Conditions in favour of a realistic multilevelled description of a decohering quantum system are examined. In this regard the first crucial observation is that the thermal effects, contrary to the conventional belief, play a minor role at low temperatures in the decoherence properties. The system-environment coupling and the environmental energy spectrum dominantly affect the decoherence. In particular, zero temperature quantum fluctuations or non-equilibrium sources can be present and influential on the decoherence rates in a wide energy range allowed by the spectrum of the environment. A crucial observation against the validity of the two-level approximation is that the decoherence rates are found to be dominated not by the long time resonant but the short time off-resonant processes. This observation is demonstrated in two stages. Firstly, our zero temperature numerical results reveal that the calculated short time decoherence rates are Gaussian-like (the time dependence of the density matrix is led by the second time derivative at t = 0). Exact analytical results are also permitted in the short time limit, which, consistent with our numerical results, reveal that this specific Gaussian-like behaviour is a property of the non-Markovian correlations in the environment. These Gaussian-like rates have no dependence on any spectral parameter (position and the width of the spectrum) except, in totality, the spectral area itself. The dependence on the spectral area is a power law. Furthermore, the Gaussian-like character at short times is independent of the number of levels (N), but the numerical value of the decoherence rates is a monotonic function of N. In this context, we demonstrate that leakage, as a characteristic multilevel effect, is dominated by the non-resonant processes. The long time behaviour of decoherence is also examined. Since our spectral model allows Markovian environmental correlations at long times, the decoherence rates in this regime become

  15. Quantum effects induced by a gap in the spectrum of atom-bath coupling constants: ''Freezing'' of atomic decay and monochromatic collective radiation

    International Nuclear Information System (INIS)

    Mogilevtsev, D.S.; Kilin, S.Ya.

    1994-08-01

    A specific kind of inhibition of atomic decay (''freezing of decay) and intense monochromatic collective radiation are predicted for a single two-level atom and for a system of atoms interacting with the field bath having the gap in the spectrum of coupling constants. (author). 10 refs, 5 figs

  16. Isometric embeddings in cosmology and astrophysics

    Indian Academy of Sciences (India)

    embedding theory, a given spacetime (or 'brane') is embedded in a higher- ..... If one recalls that the motivation (at least in part) for non-compact extra ... to successfully embed (apparently perfect fluid) astrophysical models, we typically need to.

  17. Poincare ball embeddings of the optical geometry

    International Nuclear Information System (INIS)

    Abramowicz, M A; Bengtsson, I; Karas, V; Rosquist, K

    2002-01-01

    It is shown that the optical geometry of the Reissner-Nordstroem exterior metric can be embedded in a hyperbolic space all the way down to its outer horizon. The adopted embedding procedure removes a breakdown of flat-space embeddings which occurs outside the horizon, at and below the Buchdahl-Bondi limit (R/M=9/4 in the Schwarzschild case). In particular, the horizon can be captured in the optical geometry embedding diagram. Moreover, by using the compact Poincare ball representation of the hyperbolic space, the embedding diagram can cover the whole extent of radius from spatial infinity down to the horizon. Attention is drawn to the advantages of such embeddings in an appropriately curved space: this approach gives compact embeddings and it clearly distinguishes the case of an extremal black hole from a non-extremal one in terms of the topology of the embedded horizon

  18. Perturbation Theory of Embedded Eigenvalues

    DEFF Research Database (Denmark)

    Engelmann, Matthias

    project gives a general and systematic approach to analytic perturbation theory of embedded eigenvalues. The spectral deformation technique originally developed in the theory of dilation analytic potentials in the context of Schrödinger operators is systematized by the use of Mourre theory. The group...... of dilations is thereby replaced by the unitary group generated y the conjugate operator. This then allows to treat the perturbation problem with the usual Kato theory.......We study problems connected to perturbation theory of embedded eigenvalues in two different setups. The first part deals with second order perturbation theory of mass shells in massive translation invariant Nelson type models. To this end an expansion of the eigenvalues w.r.t. fiber parameter up...

  19. An Embedded Reconfigurable Logic Module

    Science.gov (United States)

    Tucker, Jerry H.; Klenke, Robert H.; Shams, Qamar A. (Technical Monitor)

    2002-01-01

    A Miniature Embedded Reconfigurable Computer and Logic (MERCAL) module has been developed and verified. MERCAL was designed to be a general-purpose, universal module that that can provide significant hardware and software resources to meet the requirements of many of today's complex embedded applications. This is accomplished in the MERCAL module by combining a sub credit card size PC in a DIMM form factor with a XILINX Spartan I1 FPGA. The PC has the ability to download program files to the FPGA to configure it for different hardware functions and to transfer data to and from the FPGA via the PC's ISA bus during run time. The MERCAL module combines, in a compact package, the computational power of a 133 MHz PC with up to 150,000 gate equivalents of digital logic that can be reconfigured by software. The general architecture and functionality of the MERCAL hardware and system software are described.

  20. Embedding

    DEFF Research Database (Denmark)

    Høyrup, Jens

    2016-01-01

    systems, in particular place-value and quasi place-value systems. 2. The development of algebraic symbolisms. 3. The discussion whether “scientific revolutions” ever take place in mathematics, or new conceptualizations always include what preceded them. A final section investigates the relation between...

  1. Sustainable embedded software lifecycle planning

    OpenAIRE

    Lee, Dong-Hyun; In, Hoh Peter; Lee, Keun; Park, Sooyong; Hinchey, Mike

    2012-01-01

    peer-reviewed Time-to-market is a crucial factor in increasing market share in the consumer electronics (CE) market. Furthermore, fierce competition in the market tends to sharply lower the prices of brand-new CE products as soon as they are released. Software-intensive embedded system design methods such as hardware/software co-design have been studied with the goal of reducing development lead-time by designing hardware and software simultaneously. Many researchers, however, concentra...

  2. Embedded multiprocessors scheduling and synchronization

    CERN Document Server

    Sriram, Sundararajan

    2009-01-01

    Techniques for Optimizing Multiprocessor Implementations of Signal Processing ApplicationsAn indispensable component of the information age, signal processing is embedded in a variety of consumer devices, including cell phones and digital television, as well as in communication infrastructure, such as media servers and cellular base stations. Multiple programmable processors, along with custom hardware running in parallel, are needed to achieve the computation throughput required of such applications. Reviews important research in key areas related to the multiprocessor implementation of multi

  3. Bilipschitz embedding of homogeneous fractals

    OpenAIRE

    Lü, Fan; Lou, Man-Li; Wen, Zhi-Ying; Xi, Li-Feng

    2014-01-01

    In this paper, we introduce a class of fractals named homogeneous sets based on some measure versions of homogeneity, uniform perfectness and doubling. This fractal class includes all Ahlfors-David regular sets, but most of them are irregular in the sense that they may have different Hausdorff dimensions and packing dimensions. Using Moran sets as main tool, we study the dimensions, bilipschitz embedding and quasi-Lipschitz equivalence of homogeneous fractals.

  4. Corrosion Monitors for Embedded Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Alex L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pfeifer, Kent B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casias, Adrian L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    We have developed and characterized novel in-situ corrosion sensors to monitor and quantify the corrosive potential and history of localized environments. Embedded corrosion sensors can provide information to aid health assessments of internal electrical components including connectors, microelectronics, wires, and other susceptible parts. When combined with other data (e.g. temperature and humidity), theory, and computational simulation, the reliability of monitored systems can be predicted with higher fidelity.

  5. Characterization of Embedded BPM Collimators

    CERN Document Server

    VALENTINO, Gianluca

    2015-01-01

    During LS1, 16 tertiary collimators (TCTs) and 2 secondary collimators (TCSGs) in IR6 were replaced by new embedded BPM collimators. The BPM functionality allows the possibility to align the collimators more quickly and therefore be able to respond faster to machine configuration changes, as well as a direct monitoring of the beam orbit at the collimators. Following an initial commissioning phase, an MD was carried out to test the new collimators and acquisition electronics with beam in the LHC.

  6. Light forces on an indium atomic beam

    International Nuclear Information System (INIS)

    Kloeter, B.

    2007-01-01

    In this thesis it was studied, whether indium is a possible candidate for the nanostructuration respectively atomic lithography. For this known method for the generation and stabilization of the light necessary for the laser cooling had to be fitted to the special properties of indium. The spectroscopy of indium with the 451 nm and the 410 nm light yielded first hints that the formulae for the atom-light interaction for a two-level atom cannot be directly transferred to the indium atom. By means of the obtained parameters of the present experiment predictions for a possible Doppler cooling of the indium atomic beam were calculated. Furthermore the possibility for the direct deposition of indium on a substrate was studied

  7. Suppression of Rabi oscillations for moving atoms

    International Nuclear Information System (INIS)

    Navarro, B.; Egusquiza, I. L.; Muga, J. G.; Hegerfeldt, G. C.

    2003-01-01

    The well-known laser-induced Rabi oscillations of a two-level atom are shown to be suppressed under certain conditions when the atom is entering a laser-illuminated region. For temporal Rabi oscillations the effect has two regimes: a first classical-like one, taking place at intermediate atomic velocities, and a second purely quantum case at low velocities. The classical regime is associated with the formation of incoherent internal states of the atom in the laser region, whereas in the quantum, low velocity regime the laser projects the atom onto a pure internal state that can be controlled by detuning. Spatial Rabi oscillations are only suppressed in this low velocity, quantum regime

  8. Engineering quantum hyperentangled states in atomic systems

    Science.gov (United States)

    Nawaz, Mehwish; -Islam, Rameez-ul; Abbas, Tasawar; Ikram, Manzoor

    2017-11-01

    Hyperentangled states have boosted many quantum informatics tasks tremendously due to their high information content per quantum entity. Until now, however, the engineering and manipulation of such states were limited to photonic systems only. In present article, we propose generating atomic hyperentanglement involving atomic internal states as well as atomic external momenta states. Hypersuperposition, hyperentangled cluster, Bell and Greenberger-Horne-Zeilinger states are engineered deterministically through resonant and off-resonant Bragg diffraction of neutral two-level atoms. Based on the characteristic parameters of the atomic Bragg diffraction, such as comparatively large interaction times and spatially well-separated outputs, such decoherence resistant states are expected to exhibit good overall fidelities and offer the evident benefits of full controllability, along with extremely high detection efficiency, over the counterpart photonic states comprised entirely of flying qubits.

  9. Liquid-Embedded Elastomer Electronics

    Science.gov (United States)

    Kramer, Rebecca; Majidi, Carmel; Park, Yong-Lae; Paik, Jamie; Wood, Robert

    2012-02-01

    Hyperelastic sensors are fabricated by embedding a silicone rubber film with microchannels of conductive liquid. In the case of soft tactile sensors, pressing the surface of the elastomer will deform the cross-section of underlying channels and change their electrical resistance. Soft pressure sensors may be employed in a variety of applications. For example, a network of pressure sensors can serve as artificial skin by yielding detailed information about contact pressures. This concept was demonstrated in a hyperelastic keypad, where perpendicular conductive channels form a quasi-planar network within an elastomeric matrix that registers the location, intensity and duration of applied pressure. In a second demonstration, soft curvature sensors were used for joint angle proprioception. Because the sensors are soft and stretchable, they conform to the host without interfering with the natural mechanics of motion. This marked the first use of liquid-embedded elastomer electronics to monitor human or robotic motion. Finally, liquid-embedded elastomers may be implemented as conductors in applications that call for flexible or stretchable circuitry, such as robotic origami.

  10. Embedding of the radiation cosmos

    International Nuclear Information System (INIS)

    Wang, J.Z.

    1986-01-01

    The embedding of the Friedmann manifold into a higher dimensional Minkowski space is investigated. As solutions of the Friedmann equation with vanishing cosmological term, Friedmann models describe a first expanding, then contracting universe and predict a big bang singularity. For cosmic time t → 0, R(t) → 0, there is an infinite scalar, curvature in the matter cosmos, and an infinite eigenvalue corresponding to the unique timelike eigenvector of the energy-momentum tensor in the radiation cosmos. The big bang, therefore, is an intrinsic singularity of the space time. To investigate the singularity one resorts to the embedding of the Friedmann manifold into a higher dimensional Minkowski space. For the matter cosmos such an investigation has already been done (Lauro and Schucking, 1984). However, the matter cosmos is not a suitable model to discuss the very early universe where the radiation dominates. Geometric properties, such as the Riemann tensor, the Guassian curvature and the global behavior of the geodesics of the embedded manifold, are discussed in detail

  11. Atom-surface potentials and atom interferometry

    International Nuclear Information System (INIS)

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  12. Embedding initial data for black hole collisions

    OpenAIRE

    Romano, Joseph D.; Price, Richard H.

    1994-01-01

    We discuss isometric embedding diagrams for the visualization of initial data for the problem of the head-on collision of two black holes. The problem of constructing the embedding diagrams is explicitly presented for the best studied initial data, the Misner geometry. We present a partial solution of the embedding diagrams and discuss issues related to completing the solution.

  13. Line splitting and modified atomic decay of atoms coupled with N quantized cavity modes

    Science.gov (United States)

    Zhu, Yifu

    1992-05-01

    We study the interaction of a two-level atom with N non-degenerate quantized cavity modes including dissipations from atomic decay and cavity damps. In the strong coupling regime, the absorption or emission spectrum of weakly excited atom-cavity system possesses N + 1 spectral peaks whose linewidths are the weighted averages of atomic and cavity linewidths. The coupled system shows subnatural (supernatural) atomic decay behavior if the photon loss rates from the N cavity modes are smaller (larger) than the atomic decay rate. If N cavity modes are degenerate, they can be treated effectively as a single mode. In addition, we present numerical calculations for N = 2 to characterize the system evolution from the weak coupling to strong coupling limits.

  14. Structural, electronic and magnetic properties of transition-metal embedded zigzag-edged graphene nanoribbons

    International Nuclear Information System (INIS)

    Yu Guodong; Lü Xiaoling; Jiang Liwei; Gao Wenzhu; Zheng Yisong

    2013-01-01

    By means of ab initio calculations within density-functional theory, the structural, electronic and magnetic properties of a zigzag-edged graphene nanoribbon (ZGNR) with 3d transition-metal atoms (TMAs) (Sc–Zn) embedded in the periodically distributed single vacancies are systematically studied. Different from the pristine ZGNR, all of these composite structures show the subband structures with nontrivial spin polarizations, regardless of the type and the embedding position of the TMA. Embedding one kind of these atoms (V, Cr, Ni, Cu or Zn) near one ribbon edge can cause a notable edge distortion. Except for the cases of Sc, Fe and Co doping, other kinds of TMAs embedded near an edge of the ribbon can suppress the inherent magnetism of the zigzag edge. By further analysis, we find that two effects are responsible for the suppression of edge magnetism. One is the variation of the occupied spin-polarized subbands due to the hybridization of the edge state of the ZGNR and 3d atomic states of the dopant. The other is the delocalization of the edge state caused by the exotic TMA. The unilateral magnetism of these TMA-embedded ZGNRs can be utilized to realize the spin-polarized electronic transport, which is the key electronic property in the context of spintronics applications of carbon-based materials. (paper)

  15. Controllable optical bistability in photonic-crystal one-atom laser

    International Nuclear Information System (INIS)

    Guo Xiaoyong; Lue Shuchen

    2009-01-01

    We investigate the property of optical bistability in a photonic-crystal one-atom laser when nonlinear microcavity is present. The physical system consists of a coherently driven two-level light emitter strongly coupled to a high-quality microcavity which is embedded within a photonic crystal and another coherent probing field which has incident into the microcavity. In our case, the microcavity is fabricated by nonlinear material and placed as an impurity in photonic crystal. This study reveals that such a system can exhibit optical bistability. The dependence of threshold value and hysteresis loop on the photonic band gap of the photonic crystal, driving field Rabi frequency and dephasing processes, are studied. Our results clearly illustrate the ability to control optical bistability through suitable photonic-crystal architectures and external coherent driving field, and this study suggests that in a photonic-crystal nonlinear microcavity, the one-atom laser acts as an effective controllable bistable device in the design of all-light digital computing systems in the near future.

  16. Exotic atoms

    International Nuclear Information System (INIS)

    Kunselman, R.

    1993-01-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation

  17. Entanglement measures in embedding quantum simulators with nuclear spins

    Science.gov (United States)

    Xin, Tao; Pedernales, Julen S.; Solano, Enrique; Long, Gui-Lu

    2018-02-01

    We implement an embedding quantum simulator (EQS) in nuclear spin systems. The experiment consists of a simulator of up to three qubits, plus a single ancillary qubit, where we are able to efficiently measure the concurrence and the three-tangle of two-qubit and three-qubit systems as they undergo entangling dynamics. The EQS framework allows us to drastically reduce the number of measurements needed for this task, which otherwise would require full-state reconstruction of the qubit system. Our simulator is built of the nuclear spins of four 13C atoms in a molecule of trans-crotonic acid manipulated with NMR techniques.

  18. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  19. Propagation of frequency-chirped laser pulses in a medium of atoms with a Λ-level scheme

    International Nuclear Information System (INIS)

    Demeter, G.; Dzsotjan, D.; Djotyan, G. P.

    2007-01-01

    We study the propagation of frequency-chirped laser pulses in optically thick media. We consider a medium of atoms with a Λ level-scheme (Lambda atoms) and also, for comparison, a medium of two-level atoms. Frequency-chirped laser pulses that induce adiabatic population transfer between the atomic levels are considered. They induce transitions between the two lower (metastable) levels of the Λ-atoms and between the ground and excited states of the two-level atoms. We show that associated with this adiabatic population transfer in Λ-atoms, there is a regime of enhanced transparency of the medium--the pulses are distorted much less than in the medium of two-level atoms and retain their ability to transfer the atomic population much longer during propagation

  20. Direct Power Control for Three-Phase Two-Level Voltage-Source Rectifiers Based on Extended-State Observation

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Yan, Zhuo

    2016-01-01

    This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent characte......This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent...

  1. Permutation entropy with vector embedding delays

    Science.gov (United States)

    Little, Douglas J.; Kane, Deb M.

    2017-12-01

    Permutation entropy (PE) is a statistic used widely for the detection of structure within a time series. Embedding delay times at which the PE is reduced are characteristic timescales for which such structure exists. Here, a generalized scheme is investigated where embedding delays are represented by vectors rather than scalars, permitting PE to be calculated over a (D -1 ) -dimensional space, where D is the embedding dimension. This scheme is applied to numerically generated noise, sine wave and logistic map series, and experimental data sets taken from a vertical-cavity surface emitting laser exhibiting temporally localized pulse structures within the round-trip time of the laser cavity. Results are visualized as PE maps as a function of embedding delay, with low PE values indicating combinations of embedding delays where correlation structure is present. It is demonstrated that vector embedding delays enable identification of structure that is ambiguous or masked, when the embedding delay is constrained to scalar form.

  2. French processes for waste embedding. The use of epoxy resin for waste containment

    International Nuclear Information System (INIS)

    Augustin, X.; Gauthey, J.C.

    1993-01-01

    The low- and medium-level wastes generated by nuclear facilities when operating as well as during their decommissioning (dismantling, decontamination, etc.) are embedded for the purpose of obtaining a product suitable for disposal. Due to the varieties of waste produced, it was necessary to resort to multi-purpose techniques to solve problems relating to their embedding. The process for waste embedding in thermosetting polymer (polyester, epoxy) developed by the French Atomic Energy Commission (CEA) and its subsidiary TECHNICATOME is easy to operate and yields excellent results having regard to volume reduction and containment of radioisotopes (particularly caesium). The industrial development of this process has led to the design of small, flexible, fixed or mobile, embedding stations. Examples illustrating the increasing use of this process during facility dismantling are described

  3. Habitual Tastes and Embedded Taste

    DEFF Research Database (Denmark)

    Hedegaard, Liselotte

    2016-01-01

    The interest of this paper is to position taste within the framework of time. This might seem peculiar given that taste, in its physical sense, is referred to as an ephemeral experience taking place in the mouth. Taste, however, is more than that. It is the transient experience that infiltrates...... may be bridged by story-telling or other ways of handing over historically embedded practices, but this leaves a more fundamental question unanswered. Namely, that given that all remembrance has individual recollection as the point of departure, then how does individual recollection of tastes...

  4. Professional Windows Embedded Compact 7

    CERN Document Server

    Phung, Samuel; Joubert, Thierry; Hall, Mike

    2011-01-01

    Learn to program an array of customized devices and solutions As a compact, highly efficient, scalable operating system, Windows Embedded Compact 7 (WEC7) is one of the best options for developing a new generation of network-enabled, media-rich, and service-oriented devices. This in-depth resource takes you through the benefits and capabilities of WEC7 so that you can start using this performance development platform today. Divided into several major sections, the book begins with an introduction and then moves on to coverage of OS design, application development, advanced application developm

  5. Simulation and Embedded Smart Control

    DEFF Research Database (Denmark)

    Conrad, Finn; Fan, Zhun; Sørensen, Torben

    2006-01-01

    The paper presents results obtained from a Danish mechatronic research program focusing on intelligent motion control, simulation and embedded smart controllers for hydraulic actuators and robots as well as results from the EU projects. A mechatronic test facility with digital controllers...... for a hydraulic robot was implemented. The controllers apply digital signal processors (DSPs), and Field Programmable Gate Array, short named as FPGA, respectively. The DSP controller utilizes the dSPACE System that is suitable for real-time experimentation, evaluation and validation of control laws...... and algorithms. Furthermore, a developed IT-tool concept for controller and system design utilizing the ISO 10303 STEP Standard is proposed....

  6. Analytical Design of Passive LCL Filter for Three-phase Two-level Power Factor Correction Rectifiers

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Nymand, Morten

    2017-01-01

    This paper proposes a comprehensive analytical LCL filter design method for three-phase two-level power factor correction rectifiers (PFCs). The high frequency converter current ripple generates the high frequency current harmonics that need to be attenuated with respect to the grid standards...

  7. Quantum driving protocols for a two-level system: From generalized Landau-Zener sweeps to transitionless control

    DEFF Research Database (Denmark)

    Malossi, Nicola; Bason, Mark George; Viteau, Matthieu

    2013-01-01

    We present experimental results on the preparation of a desired quantum state in a two-level system with the maximum possible fidelity using driving protocols ranging from generalizations of the linear Landau-Zener protocol to transitionless driving protocols that ensure perfect following of the ...

  8. Testing framework for embedded languages

    Science.gov (United States)

    Leskó, Dániel; Tejfel, Máté

    2012-09-01

    Embedding a new programming language into an existing one is a widely used technique, because it fastens the development process and gives a part of a language infrastructure for free (e.g. lexical, syntactical analyzers). In this paper we are presenting a new advantage of this development approach regarding to adding testing support for these new languages. Tool support for testing is a crucial point for a newly designed programming language. It could be done in the hard way by creating a testing tool from scratch, or we could try to reuse existing testing tools by extending them with an interface to our new language. The second approach requires less work, and also it fits very well for the embedded approach. The problem is that the creation of such interfaces is not straightforward at all, because the existing testing tools were mostly not designed to be extendable and to be able to deal with new languages. This paper presents an extendable and modular model of a testing framework, in which the most basic design decision was to keep the - previously mentioned - interface creation simple and straightforward. Other important aspects of our model are the test data generation, the oracle problem and the customizability of the whole testing phase.

  9. Drilling azimuth gamma embedded design

    Directory of Open Access Journals (Sweden)

    Zhou Yi Ren

    2016-01-01

    Full Text Available Embedded drilling azimuth gamma design, the use of radioactive measuring principle embedded gamma measurement while drilling a short section analysis. Monte Carlo method, in response to the density of horizontal well logging numerical simulation of 16 orientation, the orientation of horizontal well analysed, calliper, bed boundary location, space, different formation density, formation thickness, and other factors inclined strata dip the impact by simulating 137Cs sources under different formation conditions of the gamma distribution, to determine the orientation of drilling density tool can detect window size and space, draw depth of the logging methods. The data 360° azimuth imaging, image processing method to obtain graph, display density of the formation, dip and strata thickness and other parameters, the logging methods obtain real-time geo-steering. To establish a theoretical basis for the orientation density logging while drilling method implementation and application of numerical simulation in-depth study of the MWD azimuth and density log response factors of horizontal wells.

  10. Nanofluidic Device with Embedded Nanopore

    Science.gov (United States)

    Zhang, Yuning; Reisner, Walter

    2014-03-01

    Nanofluidic based devices are robust methods for biomolecular sensing and single DNA manipulation. Nanopore-based DNA sensing has attractive features that make it a leading candidate as a single-molecule DNA sequencing technology. Nanochannel based extension of DNA, combined with enzymatic or denaturation-based barcoding schemes, is already a powerful approach for genome analysis. We believe that there is revolutionary potential in devices that combine nanochannels with nanpore detectors. In particular, due to the fast translocation of a DNA molecule through a standard nanopore configuration, there is an unfavorable trade-off between signal and sequence resolution. With a combined nanochannel-nanopore device, based on embedding a nanopore inside a nanochannel, we can in principle gain independent control over both DNA translocation speed and sensing signal, solving the key draw-back of the standard nanopore configuration. We demonstrate that we can detect - using fluorescent microscopy - successful translocation of DNA from the nanochannel out through the nanopore, a possible method to 'select' a given barcode for further analysis. We also show that in equilibrium DNA will not escape through an embedded sub-persistence length nanopore until a certain voltage bias is added.

  11. Sub-nanometre channels embedded in two-dimensional materials

    KAUST Repository

    Han, Yimo

    2017-12-04

    Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically thin p–n junctions2,3,4,5,6,7,8, metal–semiconductor contacts9,10,11, and metal–insulator barriers12,13,14 have been demonstrated. Although 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions is also necessary. Here, we report the direct synthesis of sub-nanometre-wide one-dimensional (1D) MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalysed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Using molecular dynamics simulations, we have identified other combinations of 2D materials where 1D channels can also be formed. The electronic band structure of these 1D channels offers the promise of carrier confinement in a direct-gap material and the charge separation needed to access the ultimate length scales necessary for future electronic applications.

  12. Sub-Nanometer Channels Embedded in Two-Dimensional Materials

    KAUST Repository

    Han, Yimo

    2017-07-31

    Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2-7, metal-semiconductor contacts8-10, and metal-insulator barriers11-13 have been demonstrated. While 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions are also necessary. Although external one-dimensional (1D) carbon nanotubes14 can be used to locally gate 2D materials, this adds a non-trivial third dimension, complicating device integration and flexibility. Here, we report the direct synthesis of sub-nanometer 1D MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalyzed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Molecular dynamics (MD) simulations have identified other combinations of 2D materials that could form 1D channels. Density function theory (DFT) calculation predicts these 1D channels display type II band alignment needed for carrier confinement and charge separation to access the ultimate length scales necessary for future electronic applications.

  13. A miniature magnetic waveguide for cold atoms

    International Nuclear Information System (INIS)

    Key, M.G.

    2000-09-01

    This thesis presents the first demonstration of a guide for cold atoms based on a miniature structure of four current-carrying wires. The four wires are embedded within a hollow silica fibre. Atoms are guided along the centre of a fifth hole on the axis of the fibre by the Stern-Gerlach force. A vapour cell Magneto Optical Trap (MOT), formed 1 cm above the mouth of the waveguide is the source of cold 85 Rb atoms. After cooling the atoms to 25 μK in optical molasses they fall under the influence of gravity through a magnetic funnel into the waveguide. After propagating for 2 cm, the atoms are reflected by the field of a small pinch coil wound around the base of the guide. The atoms then travel back up the fibre and out into the funnel, where they can be imaged either in fluorescence or by recapturing in the MOT. A video sequence of atoms falling into the guide and re-emerging after reflection from the pinch coil graphically illustrates the operation of the guide. The coupling efficiency and transverse temperature of the atoms is measured experimentally and in a Monte-Carlo simulation. We find an optimum coupling efficiency of 12% and we measure the spatial extent of the cloud within the fibre to be of order 100 μm. We find good agreement between experimental data and results from the numerical simulation. We have also been able to observe different thresholds for the reflection of different positive m F levels. In another experiment we are able to trap the atoms in an elongated Ioffe trap for up to two seconds, increasing the distance over which the atoms are guided. We are able to guide the atoms over distances of 40 cm with a loss rate indistinguishable from the free space loss rate. (author)

  14. Atomic reactor thermal engineering

    International Nuclear Information System (INIS)

    Kim, Gwang Ryong

    1983-02-01

    This book starts the introduction of atomic reactor thermal engineering including atomic reaction, chemical reaction, nuclear reaction neutron energy and soon. It explains heat transfer, heat production in the atomic reactor, heat transfer of fuel element in atomic reactor, heat transfer and flow of cooler, thermal design of atomic reactor, design of thermodynamics of atomic reactor and various. This deals with the basic knowledge of thermal engineering for atomic reactor.

  15. Atomic energy

    International Nuclear Information System (INIS)

    Ramanna, R.

    1978-01-01

    Development of nuclear science in India, particularly the research and development work at the Bhabha Atomic Research Centre (BARC), Bombay, is described. Among the wide range of materials developed for specific functions under rigorous conditions are nuclear pure grade uranium, zirconium and beryllium, and conventional materials like aluminium, carbon steel and stainless steels. Radioisotopes are produced and used for tracer studies in various fields. Various types of nuclear gauges and nuclear instruments are produced. Radiations have been used to develop new high yielding groundnut mutants with large kernals. The sterile male technique for pest control and radiosterilization technique to process potatoes, onions and marine foods for storage are ready for exploitation. Processes and equipment have been developed for production of electrolytic hydrogen, electrothermal phosphorus and desalinated water. Indigenously manufactured components and materials are now being used for the nuclear energy programme. Indian nuclear power programme strategy is to build heavy water reactors and to utilise their byproduct plutonium and depleted uranium to feed fast breeder reactors which will produce more fissile material than burnt. Finally a special mention has been made of the manpower development programme of the BARC. BARC has established a training school in 1957 giving advanced training in physics, chemistry and various branches of engineering and metallurgy

  16. Cross functional organisational embedded system development

    OpenAIRE

    Lennon, Sophie

    2015-01-01

    peer-reviewed Embedded system development is continuing to grow. Medical, automotive and Internet of Things are just some of the market segments. There is a tight coupling between hardware and software when developing an embedded system, often needing to meet strict performance targets, standards requirements and aggressive schedules. Embedded software developers need to consider hardware requirements in far greater detail as they can have a significant impact on the quality and value of t...

  17. Homomorphic embeddings in n-groups

    Directory of Open Access Journals (Sweden)

    Mona Cristescu

    2013-06-01

    Full Text Available We prove that an cancellative n-groupoid A can be homotopic embedded in an n-group if and only if in A are satisfied all n-ary Malcev conditions. Now we shall prove that in the presence of associative law we obtain homomorphic embeddings. Furthermore, if A has a lateral identity a such embeddings is assured by a subset of n-ary Malcev conditions - unary Malcev conditions.

  18. Bremsstrahlung in atom-atom collisions

    International Nuclear Information System (INIS)

    Amus'ya, M.Y.; Kuchiev, M.Y.; Solov'ev, A.V.

    1985-01-01

    It is shown that in the collision of a fast atom with a target atom when the frequencies are on the order of the potentials or higher, there arises bremsstrahlung comparable in intensity with the bremsstrahlung emitted by an electron with the same velocity in the field of the target atom. The mechanism by which bremsstrahlung is produced in atom-atom collisions is elucidated. Results of specific calculations of the bremsstrahlung spectra are given for α particles and helium atoms colliding with xenon

  19. Knowledge Engineering for Embedded Configuration

    DEFF Research Database (Denmark)

    Oddsson, Gudmundur Valur

    2008-01-01

    into the system the knowledge needed to achieve them. In order to understand the system, one draws simplified functional streams and identifies archetypes from the product assortment, and then one maps the two together into a system breakdown model. The system model indicates how many encapsulation models (EMs......This thesis presents a way to simplify setup of complex product systems with the help of embedded configuration. To achieve this, one has to focus on what subsystems need to communicate between themselves. The required internal knowledge is then structured at three abstraction levels......, and predefined relation types are suggested. The models are stringent and thought out so they can be implemented in software. They should allow both import and export of product knowledge from the knowledge-based system. The purpose of this work is to simplify the installation process of product systems...

  20. Embedding knowledge in a workstation

    Energy Technology Data Exchange (ETDEWEB)

    Barber, G

    1982-01-01

    This paper describes an approach to supporting work in the office. Using and extending ideas from the field of artificial intelligence (AI) it describes office work as a problem solving activity. A knowledge embedding language called OMEGA is used to embed knowledge of the organization into an office worker's workstation in order to support the office worker in his or her problem solving. A particular approach to reasoning about change and contradiction is discussed. This approach uses OMEGA's viewpoint mechanism. OMEGA's viewpoint mechanism is a general contradiction handling facility. Unlike other knowledge representation systems, when a contradiction is reached the reasons for the contradiction can be analyzed by the reduction mechanism without having to resort to a backtracking mechanism. The viewpoint mechanism is the heart of the problem solving support paradigm. This paradigm is an alternative to the classical view of problem solving in AI. Office workers are supported using the problem solving support paradigm. 16 references.

  1. Embedding Complementarity in HCI Methods and Techniques

    DEFF Research Database (Denmark)

    Nielsen, Janni; Yssing, Carsten; Tweddell Levinsen, Karin

    Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded in the tec......Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded...... the HCI paradigm in system development....

  2. Embedded Fiber Optic Sensors for Integral Armor

    National Research Council Canada - National Science Library

    Fink, Bruce

    2000-01-01

    This report describes the work performed with Production Products Manufacturing & Sales (PPMS), Inc., under the "Liquid Molded Composite Armor Smart Structures Using Embedded Sensors" Small Business Innovative Research...

  3. Graphical Model Debugger Framework for Embedded Systems

    DEFF Research Database (Denmark)

    Zeng, Kebin

    2010-01-01

    Model Driven Software Development has offered a faster way to design and implement embedded real-time software by moving the design to a model level, and by transforming models to code. However, the testing of embedded systems has remained at the code level. This paper presents a Graphical Model...... Debugger Framework, providing an auxiliary avenue of analysis of system models at runtime by executing generated code and updating models synchronously, which allows embedded developers to focus on the model level. With the model debugger, embedded developers can graphically test their design model...

  4. Multichannel analyzer embedded in FPGA

    International Nuclear Information System (INIS)

    Garcia D, A.; Hernandez D, V. M.; Vega C, H. R.; Ordaz G, O. O.; Bravo M, I.

    2017-10-01

    Ionizing radiation has different applications, so it is a very significant and useful tool, which in turn can be dangerous for living beings if they are exposed to uncontrolled doses. However, due to its characteristics, it cannot be perceived by any of the senses of the human being, so that in order to know the presence of it, radiation detectors and additional devices are required to quantify and classify it. A multichannel analyzer is responsible for separating the different pulse heights that are generated in the detectors, in a certain number of channels; according to the number of bits of the analog to digital converter. The objective of the work was to design and implement a multichannel analyzer and its associated virtual instrument, for nuclear spectrometry. The components of the multichannel analyzer were created in VHDL hardware description language and packaged in the Xilinx Vivado design suite, making use of resources such as the ARM processing core that the System on Chip Zynq contains and the virtual instrument was developed on the LabView programming graphics platform. The first phase was to design the hardware architecture to be embedded in the FPGA and for the internal control of the multichannel analyzer the application was generated for the ARM processor in C language. For the second phase, the virtual instrument was developed for the management, control and visualization of the results. The data obtained as a result of the development of the system were observed graphically in a histogram showing the spectrum measured. The design of the multichannel analyzer embedded in FPGA was tested with two different radiation detection systems (hyper-pure germanium and scintillation) which allowed determining that the spectra obtained are similar in comparison with the commercial multichannel analyzers. (Author)

  5. PSCAD modeling of a two-level space vector pulse width modulation algorithm for power electronics education

    Directory of Open Access Journals (Sweden)

    Ahmet Mete Vural

    2016-09-01

    Full Text Available This paper presents the design details of a two-level space vector pulse width modulation algorithm in PSCAD that is able to generate pulses for three-phase two-level DC/AC converters with two different switching patterns. The presented FORTRAN code is generic and can be easily modified to meet many other kinds of space vector modulation strategies. The code is also editable for hardware programming. The new component is tested and verified by comparing its output as six gating signals with those of a similar component in MATLAB library. Moreover the component is used to generate digital signals for closed-loop control of STATCOM for reactive power compensation in PSCAD. This add-on can be an effective tool to give students better understanding of the space vector modulation algorithm for different control tasks in power electronics area, and can motivate them for learning.

  6. Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields

    Energy Technology Data Exchange (ETDEWEB)

    Puthumpally-Joseph, Raiju; Charron, Eric [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Sukharev, Maxim [Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University, Mesa, Arizona 85212 (United States)

    2016-04-21

    We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.

  7. Minimax approach problem with incomplete information for the two-level hierarchical discrete-time dynamical system

    Energy Technology Data Exchange (ETDEWEB)

    Shorikov, A. F. [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002, Russia and Institute of Mathematics and Mechanics, Ural Division of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation)

    2014-11-18

    We consider a discrete-time dynamical system consisting of three controllable objects. The motions of all objects are given by the corresponding vector linear or convex discrete-time recurrent vector relations, and control system for its has two levels: basic (first or I level) that is dominating and subordinate level (second or II level) and both have different criterions of functioning and united a priori by determined informational and control connections defined in advance. For the dynamical system in question, we propose a mathematical formalization in the form of solving a multistep problem of two-level hierarchical minimax program control over the terminal approach process with incomplete information and give a general scheme for its solution.

  8. Two-level MOC calculation scheme in APOLLO2 for cross-section library generation for LWR hexagonal assemblies

    International Nuclear Information System (INIS)

    Petrov, Nikolay; Todorova, Galina; Kolev, Nikola; Damian, Frederic

    2011-01-01

    The accurate and efficient MOC calculation scheme in APOLLO2, developed by CEA for generating multi-parameterized cross-section libraries for PWR assemblies, has been adapted to hexagonal assemblies. The neutronic part of this scheme is based on a two-level calculation methodology. At the first level, a multi-cell method is used in 281 energy groups for cross-section definition and self-shielding. At the second level, precise MOC calculations are performed in a collapsed energy mesh (30-40 groups). In this paper, the application and validation of the two-level scheme for hexagonal assemblies is described. Solutions for a VVER assembly are compared with TRIPOLI4® calculations and direct 281g MOC solutions. The results show that the accuracy is close to that of the 281g MOC calculation while the CPU time is substantially reduced. Compared to the multi-cell method, the accuracy is markedly improved. (author)

  9. Fabrication of Ni stamp with high aspect ratio, two-leveled, cylindrical microstructures using dry etching and electroplating

    DEFF Research Database (Denmark)

    Petersen, Ritika Singh; Keller, Stephan Sylvest; Hansen, Ole

    2015-01-01

    obtained by defining a reservoir and a separating trench with different depths of 85 and 125 μm, respectively, in a single embossing step. The fabrication of the required two leveled stamp is done using a modified DEEMO (dry etching, electroplating and molding) process. Dry etching using the Bosch process...... and electroplating are optimized to obtain a stamp with smooth stamp surfaces and a positive sidewall profile. Using this stamp, hot embossing is performed successfully with excellent yield and high replication fidelity....

  10. An EOQ Model with Stock-Dependent Demand under Two Levels of Trade Credit and Time Value of Money

    OpenAIRE

    H.A.O. Jia-Qin; M.O. Jiangtao

    2013-01-01

    Since the value of money changes with time, it is necessary to take account of the influence of time factor in making the replenishment policy. In this study, to investigate the influence of the time value of money to the inventory strategy, an inventory system for deteriorating items with stock-dependent demand is investigated under two levels of trade credit. The method to efficiently determine the optimal cycle time is presented. Numerical examples are provided to demonstrate the model and...

  11. Asynchronous Two-Level Checkpointing Scheme for Large-Scale Adjoints in the Spectral-Element Solver Nek5000

    Energy Technology Data Exchange (ETDEWEB)

    Schanen, Michel; Marin, Oana; Zhang, Hong; Anitescu, Mihai

    2016-01-01

    Adjoints are an important computational tool for large-scale sensitivity evaluation, uncertainty quantification, and derivative-based optimization. An essential component of their performance is the storage/recomputation balance in which efficient checkpointing methods play a key role. We introduce a novel asynchronous two-level adjoint checkpointing scheme for multistep numerical time discretizations targeted at large-scale numerical simulations. The checkpointing scheme combines bandwidth-limited disk checkpointing and binomial memory checkpointing. Based on assumptions about the target petascale systems, which we later demonstrate to be realistic on the IBM Blue Gene/Q system Mira, we create a model of the expected performance of our checkpointing approach and validate it using the highly scalable Navier-Stokes spectralelement solver Nek5000 on small to moderate subsystems of the Mira supercomputer. In turn, this allows us to predict optimal algorithmic choices when using all of Mira. We also demonstrate that two-level checkpointing is significantly superior to single-level checkpointing when adjoining a large number of time integration steps. To our knowledge, this is the first time two-level checkpointing had been designed, implemented, tuned, and demonstrated on fluid dynamics codes at large scale of 50k+ cores.

  12. Performance and meat quality traits of beef heifers fed with two levels of concentrate and ruminally undegradable protein.

    Science.gov (United States)

    Duarte, Marcio de Souza; Paulino, Pedro Veiga Rodrigues; Valadares Filho, Sebastião de Campos; Paulino, Mario Fonseca; Detmann, Edenio; Zervoudakis, Joanis Tilemahos; Monnerat, João Paulo Ismerio dos Santos; Viana, Gabriel da Silva; Silva, Luiz Henrique P; Serão, Nicola Vergara Lopes

    2011-04-01

    The effects of two levels of concentrate and ruminally undegradable protein (RUP) on performance, intake, digestibility, carcass characteristics, meat quality traits, and commercial cuts yield were assessed. Twenty crossbred heifers (240 kg average body weight) were used. At the beginning of the trial, four animals were slaughtered as reference group and the 16 remaining animals were randomly assigned to four treatments, in a 2 × 2 factorial design: two levels of concentrate (40% and 80%, dry matter (DM) basis) and two levels of RUP (48.79% and 27.19% of CP). At the end of the trial, all the animals were slaughtered. There was no interaction (P > 0.05) between concentrate and RUP levels. Dry matter intake and nutrients digestibility was not affected (P > 0.05) by RUP level. Heifers fed the highest RUP level had greater (P  0.05) DMI and ADG. Heifers fed diets with 80% concentrate had greater intake of TDN and EE, and lower intake of NDF (P RUP levels did not affect (P > 0.05) the carcass characteristics and carcass gain composition. Heifers fed 80% concentrate diets had larger (P  0.05) the composition of carcass gain. There was no effect (P > 0.05) of RUP and concentrate levels on meat quality traits and commercial cut yields.

  13. An Indication of Reliability of the Two-Level Approach of the AWIN Welfare Assessment Protocol for Horses

    Directory of Open Access Journals (Sweden)

    Irena Czycholl

    2018-01-01

    Full Text Available To enhance feasibility, the Animal Welfare Indicators (AWIN assessment protocol for horses consists of two levels: the first is a visual inspection of a sample of horses performed from a distance, the second a close-up inspection of all horses. The aim was to analyse whether information would be lost if only the first level were performed. In this study, 112 first and 112 second level assessments carried out on a subsequent day by one observer were compared by calculating the Spearman’s Rank Correlation Coefficient (RS, Intraclass Correlation Coefficients (ICC, Smallest Detectable Changes (SDC and Limits of Agreements (LoA. Most indicators demonstrated sufficient reliability between the two levels. Exceptions were the Horse Grimace Scale, the Avoidance Distance Test and the Voluntary Human Approach Test (e.g., Voluntary Human Approach Test: RS: 0.38, ICC: 0.38, SDC: 0.21, LoA: −0.25–0.17, which could, however, be also interpreted as a lack of test-retest reliability. Further disagreement was found for the indicator consistency of manure (RS: 0.31, ICC: 0.38, SDC: 0.36, LoA: −0.38–0.36. For these indicators, an adaptation of the first level would be beneficial. Overall, in this study, the division into two levels was reliable and might therewith have the potential to enhance feasibility in other welfare assessment schemes.

  14. Comparison of Cervical Kinematics, Pain, and Functional Disability Between Single- and Two-level Anterior Cervical Discectomy and Fusion.

    Science.gov (United States)

    Chien, Andy; Lai, Dar-Ming; Wang, Shwu-Fen; Hsu, Wei-Li; Cheng, Chih-Hsiu; Wang, Jaw-Lin

    2016-08-01

    A prospective, time series design. The purpose of this study is two-fold: firstly, to investigate the impact of altered cervical alignment and range of motion (ROM) on patients' self-reported outcomes after anterior cervical discectomy and fusion (ACDF), and secondly, to comparatively differentiate the influence of single- and two-level ACDF on the cervical ROM and adjacent segmental kinematics up to 12-month postoperatively. ACDF is one of the most commonly employed surgical interventions to treat degenerative disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes. Sixty-two patients (36 males; 55.63 ± 11.6 yrs) undergoing either a single- or consecutive two-level ACDF were recruited. The clinical outcomes were assessed with the Pain Visual Analogue Scale (VAS) and the Neck Disability Index (NDI). Radiological results included cervical lordosis, global C2-C7 ROM, ROM of the Functional Spinal Unit (FSU), and its adjacent segments. The outcome measures were collected preoperatively and then at 3, 6, and 12-month postoperatively. A significant reduction of both VAS and NDI was found for both groups from the preoperative to 3-month period (P < 0.01). Pearson correlation revealed no significant correlation between global ROM with neither VAS (P = 0.667) nor NDI (P = 0.531). A significant reduction of global ROM was identified for the two-level ACDF group at 12 months (P = 0.017) but not for the single-level group. A significant interaction effect was identified for the upper adjacent segment ROM (P = 0.024) but not at the lower adjacent segment. Current study utilized dynamic radiographs to comparatively evaluate the biomechanical impact of single- and two-level ACDF. The results highlighted that the two-level group demonstrated a greater reduction of global ROM coupled with an increased upper adjacent segmental compensatory motions that

  15. Atomic weight versus atomic mass controversy

    International Nuclear Information System (INIS)

    Holden, N.E.

    1985-01-01

    A problem for the Atomic Weights Commission for the past decade has been the controversial battle over the names ''atomic weight'' and ''atomic mass''. The Commission has considered the arguments on both sides over the years and it appears that this meeting will see more of the same discussion taking place. In this paper, I review the situation and offer some alternatives

  16. Fracture of vacancy-defected carbon nanotubes and their embedded nanocomposites

    International Nuclear Information System (INIS)

    Xiao Shaoping; Hou Wenyi

    2006-01-01

    In this paper, we investigate effects of vacancy defects on fracture of carbon nanotubes and carbon nanotube/aluminum composites. Our studies show that even a one-atom vacancy defect can dramatically reduce the failure stresses and strains of carbon nanotubes. Consequently, nanocomposites, in which vacancy-defected nanotubes are embedded, exhibit different characteristics from those in which pristine nanotubes are embedded. It has been found that defected nanotubes with a small volume fraction cannot reinforce but instead weaken nanocomposite materials. Although a large volume fraction of defected nanotubes can slightly increase the failure stresses of nanocomposites, the failure strains of nanocomposites are always decreased

  17. Enhancing optical nonreciprocity by an atomic ensemble in two coupled cavities

    Science.gov (United States)

    Song, L. N.; Wang, Z. H.; Li, Yong

    2018-05-01

    We study the optical nonreciprocal propagation in an optical molecule of two coupled cavities with one of them interacting with a two-level atomic ensemble. The effect of increasing the number of atoms on the optical isolation ratio of the system is studied. We demonstrate that the significant nonlinearity supplied by the coupling of the atomic ensemble with the cavity leads to the realization of greatly-enhanced optical nonreciprocity compared with the case of single atom.

  18. Multithreading for Embedded Reconfigurable Multicore Systems

    NARCIS (Netherlands)

    Zaykov, P.G.

    2014-01-01

    In this dissertation, we address the problem of performance efficient multithreading execution on heterogeneous multicore embedded systems. By heterogeneous multicore embedded systems we refer to those, which have real-time requirements and consist of processor tiles with General Purpose Processor

  19. Multithreading for embedded reconfigurable multicore systems

    NARCIS (Netherlands)

    Zaykov, P.G.

    2014-01-01

    In this dissertation, we address the problem of performance efficient multithreading execution on heterogeneous multicore embedded systems. By heterogeneous multicore embedded systems we refer to those, which have real-time requirements and consist of processor tiles with General Purpose Processor

  20. TTCN-3 for distributed testing embedded systems

    NARCIS (Netherlands)

    Blom, S.C.C.; Deiß, T.; Ioustinova, N.; Kontio, A.; Pol, van de J.C.; Rennoch, A.; Sidorova, N.; Virbitskaite, I.; Voronkov, A.

    2007-01-01

    Abstract. TTCN-3 is a standardized language for specifying and executing test suites that is particularly popular for testing embedded systems. Prior to testing embedded software in a target environment, the software is usually tested in the host environment. Executing in the host environment often

  1. Verification and Performance Analysis for Embedded Systems

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand

    2009-01-01

    This talk provides a thorough tutorial of the UPPAAL tool suite for, modeling, simulation, verification, optimal scheduling, synthesis, testing and performance analysis of embedded and real-time systems.......This talk provides a thorough tutorial of the UPPAAL tool suite for, modeling, simulation, verification, optimal scheduling, synthesis, testing and performance analysis of embedded and real-time systems....

  2. Teaching Embedded System Concepts for Technological Literacy

    Science.gov (United States)

    Winzker, M.; Schwandt, A.

    2011-01-01

    A basic understanding of technology is recognized as important knowledge even for students not connected with engineering and computer science. This paper shows that embedded system concepts can be taught in a technological literacy course. An embedded system teaching block that has been used in an electronics module for non-engineers is…

  3. Embedding methods for phi4-interaction

    International Nuclear Information System (INIS)

    Hanckowiak, J.

    1985-01-01

    The idea of embedding a given theory in a class of similar theories is applied to quantum field theory in the case of phi 4 -interaction to derive different equations for the generating functional. The number of possible embeddings has been restricted by demanding that for the defined projections of the generating functional a closed system of equations be obtained

  4. Embedded Java security security for mobile devices

    CERN Document Server

    Debbabi, Mourad; Talhi, Chamseddine

    2007-01-01

    Java brings more functionality and versatility to the world of mobile devices, but it also introduces new security threats. This book contains a presentation of embedded Java security and presents the main components of embedded Java. It gives an idea of the platform architecture and is useful for researchers and practitioners.

  5. Heterogeneous Embedded Real-Time Systems Environment

    Science.gov (United States)

    2003-12-01

    AFRL-IF-RS-TR-2003-290 Final Technical Report December 2003 HETEROGENEOUS EMBEDDED REAL - TIME SYSTEMS ENVIRONMENT Integrated...HETEROGENEOUS EMBEDDED REAL - TIME SYSTEMS ENVIRONMENT 6. AUTHOR(S) Cosmo Castellano and James Graham 5. FUNDING NUMBERS C - F30602-97-C-0259

  6. Embedded Systems Design with 8051 Microcontrollers

    DEFF Research Database (Denmark)

    Karakahayov, Zdravko; Winther, Ole; Christensen, Knud Smed

    Textbook on embedded microcontrollers. Example microcontroller family: Intel 8051 with special emphasis on Philips 80C552. Structure, design examples and programming in C and assembler. Hardware - software codesign. EProm emulator.......Textbook on embedded microcontrollers. Example microcontroller family: Intel 8051 with special emphasis on Philips 80C552. Structure, design examples and programming in C and assembler. Hardware - software codesign. EProm emulator....

  7. The influence of atomic coherence and dipole–dipole interaction on ...

    Indian Academy of Sciences (India)

    Entanglement is an essential feature of quantum mechanics. ... entanglement in a system of two identical two-level atoms with one-photon ..... [1] M A Nielsen and I L Chuang, Quantum computation and quantum information (Cambridge.

  8. Highly excited atoms

    International Nuclear Information System (INIS)

    Kleppner, D.; Littman, M.G.; Zimmerman, M.L.

    1981-01-01

    Highly excited atoms are often called Rydberg atoms. These atoms have a wealth of exotic properties which are discussed. Of special interest, are the effects of electric and magnetic fields on Rydberg atoms. Ordinary atoms are scarcely affected by an applied electric or magnetic field; Rydberg atoms can be strongly distorted and even pulled apart by a relatively weak electric field, and they can be squeezed into unexpected shapes by a magnetic field. Studies of the structure of Rydberg atoms in electric and magnetic fields have revealed dramatic atomic phenomena that had not been observed before

  9. Atomistic simulations of the effect of embedded hydrogen and helium on the tensile properties of monocrystalline and nanocrystalline tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhe [Department of Physics, Beihang University, Beijing 100191 (China); Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Kecskes, Laszlo J. [US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD 21005 (United States); Zhu, Kaigui, E-mail: kgzhu@buaa.edu.cn [Department of Physics, Beihang University, Beijing 100191 (China); Beijing Key Laboratory of Advanced Nuclear Energy Materials and Physics, Beihang University, Beijing 100191 (China); Wei, Qiuming, E-mail: qwei@uncc.edu [Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States)

    2016-12-01

    Uniaxial tensile properties of monocrystalline tungsten (MC-W) and nanocrystalline tungsten (NC-W) with embedded hydrogen and helium atoms have been investigated using molecular dynamics (MD) simulations in the context of radiation damage evolution. Different strain rates have been imposed to investigate the strain rate sensitivity (SRS) of the samples. Results show that the plastic deformation processes of MC-W and NC-W are dominated by different mechanisms, namely dislocation-based for MC-W and grain boundary-based activities for NC-W, respectively. For MC-W, the SRS increases and a transition appears in the deformation mechanism with increasing embedded atom concentration. However, no obvious embedded atom concentration dependence of the SRS has been observed for NC-W. Instead, in the latter case, the embedded atoms facilitate GB sliding and intergranular fracture. Additionally, a strong strain enhanced He cluster growth has been observed. The corresponding underlying mechanisms are discussed. - Highlights: • Uniaxial tensile behavior of monocrystal tungsten (C-W) and nanocrystalline W (NC-W) have been investigated. • Dislocation-based activities dominate the plastic deformation of MC-W. • Grain boundary-based activities dominate the plastic deformation of NC-W. • H/He atoms have significant impacts on the tensile behavior of MC-W and NC-W. • Strong strain enhanced He cluster growth has been revealed.

  10. Laser-assisted atom-atom collisions

    International Nuclear Information System (INIS)

    Roussel, F.

    1984-01-01

    The basic layer-assisted atom-atom collision processes are reviewed in order to get a simpler picture of the main physical facts. The processes can be separated into two groups: optical collisions where only one atom is changing state during the collision, the other acting as a spectator atom, and radiative collisions where the states of the two atoms are changing during the collision. All the processes can be interpreted in terms of photoexcitation of the quasimolecule formed during the collisional process. (author)

  11. Energy eigenvalues of helium-like atoms in dense plasmas

    International Nuclear Information System (INIS)

    Hashino, Tasuke; Nakazaki, Shinobu; Kato, Takako; Kashiwabara, Hiromichi.

    1987-04-01

    Calculations based on a variational method with wave functions including the correlation of electrons are carried out to obtain energy eigenvalues of Schroedinger's equation for helium-like atoms embedded in dense plasmas, taking the Debye-Hueckel approximation. Energy eigenvalues for the 1 1 S, 2 1 S, and 2 3 S states are obtained as a function of Debye screening length. (author)

  12. Long Range Forces between Atomic Impurities in Liquid Helium

    International Nuclear Information System (INIS)

    Dupont-Roc, J.

    2002-01-01

    Van der Waals or Casimir interaction between neutral quantum objects in their ground state is known to be universally attractive. This is not necessarily so when these objects are embedded in a polarizable medium. We show that atomic impurities in liquid helium may indeed realize repulsive forces, and even Van der Waals and Casimir forces with different signs. (author)

  13. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    International Nuclear Information System (INIS)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon

    2010-01-01

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  14. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon [Wooridul Spine Hospital, Seoul (Korea, Republic of)

    2010-08-15

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  15. Code ATOM for calculation of atomic characteristics

    International Nuclear Information System (INIS)

    Vainshtein, L.A.

    1990-01-01

    In applying atomic physics to problems of plasma diagnostics, it is necessary to determine some atomic characteristics, including energies and transition probabilities, for very many atoms and ions. Development of general codes for calculation of many types of atomic characteristics has been based on general but comparatively simple approximate methods. The program ATOM represents an attempt at effective use of such a general code. This report gives a brief description of the methods used, and the possibilities of and limitations to the code are discussed. Characteristics of the following processes can be calculated by ATOM: radiative transitions between discrete levels, radiative ionization and recombination, collisional excitation and ionization by electron impact, collisional excitation and ionization by point heavy particle (Born approximation only), dielectronic recombination, and autoionization. ATOM explores Born (for z=1) or Coulomb-Born (for z>1) approximations. In both cases exchange and normalization can be included. (N.K.)

  16. Hardware standardization for embedded systems

    International Nuclear Information System (INIS)

    Sharma, M.K.; Kalra, Mohit; Patil, M.B.; Mohanty, Ashutos; Ganesh, G.; Biswas, B.B.

    2010-01-01

    Reactor Control Division (RCnD) has been one of the main designers of safety and safety related systems for power reactors. These systems have been built using in-house developed hardware. Since the present set of hardware was designed long ago, a need was felt to design a new family of hardware boards. A Working Group on Electronics Hardware Standardization (WG-EHS) was formed with an objective to develop a family of boards, which is general purpose enough to meet the requirements of the system designers/end users. RCnD undertook the responsibility of design, fabrication and testing of boards for embedded systems. VME and a proprietary I/O bus were selected as the two system buses. The boards have been designed based on present day technology and components. The intelligence of these boards has been implemented on FPGA/CPLD using VHDL. This paper outlines the various boards that have been developed with a brief description. (author)

  17. Field tests on partial embedment effects (embedment effect tests on soil-structure interaction)

    International Nuclear Information System (INIS)

    Kurimoto, O.; Tsunoda, T.; Inoue, T.; Izumi, M.; Kusakabe, K.; Akino, K.

    1993-01-01

    A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and lndustry (MITI) of Japan. The nuclear reactor buildings are partially embedded due to conditions for the construction or building arrangement in Japan. It is necessary to verify the partial embedment effects by experiments and analytical studies in order to incorporate the effects in the seismic design. Forced vibration tests, therefore, were performed using a model with several types of embedment. Correlated simulation analyses were also performed and the characteristics of partial embedment effects on soil-structure interaction were evaluated. (author)

  18. Entropy as a measure of the noise extent in a two-level quantum feedback controlled system

    Institute of Scientific and Technical Information of China (English)

    Wang Tao-Bo; Fang Mao-Fa; Hu Yao-Hua

    2007-01-01

    By introducing the von Neumann entropy as a measure of the extent of noise, this paper discusses the entropy evolution in a two-level quantum feedback controlled system. The results show that the feedback control can induce the reduction of the degree of noise, and different control schemes exhibit different noise controlling ability, the extent of the reduction also related with the position of the target state on the Bloch sphere. It is shown that the evolution of entropy can provide a real time noise observation and a systematic guideline to make reasonable choice of control strategy.

  19. Comparison of PI and PR current controllers applied on two-level VSC-HVDC transmission system

    DEFF Research Database (Denmark)

    Manoloiu, A.; Pereria, H.A.; Teodorescu, Remus

    2015-01-01

    This paper analyzes differences between αβ and dq reference frames regarding the control of two-level VSC-HVDC current loop and dc-link voltage outer loop. In the first part, voltage feedforward effect is considered with PI and PR controllers. In the second part, the feedforward effect is removed...... and the PR gains are tuned to keep the dynamic performance. Also, the power feedforward is removed and the outer loop PI controller is tuned in order to maintain the system dynamic performance. The paper is completed with simulation results, which highlight the advantages of using PR controller....

  20. 2L-PCA: a two-level principal component analyzer for quantitative drug design and its applications.

    Science.gov (United States)

    Du, Qi-Shi; Wang, Shu-Qing; Xie, Neng-Zhong; Wang, Qing-Yan; Huang, Ri-Bo; Chou, Kuo-Chen

    2017-09-19

    A two-level principal component predictor (2L-PCA) was proposed based on the principal component analysis (PCA) approach. It can be used to quantitatively analyze various compounds and peptides about their functions or potentials to become useful drugs. One level is for dealing with the physicochemical properties of drug molecules, while the other level is for dealing with their structural fragments. The predictor has the self-learning and feedback features to automatically improve its accuracy. It is anticipated that 2L-PCA will become a very useful tool for timely providing various useful clues during the process of drug development.

  1. Resonance fluorescence from an atom in a squeezed vacuum

    Science.gov (United States)

    Carmichael, H. J.; Lane, A. S.; Walls, D. F.

    1987-06-01

    The fluorescent spectrum for a two-level atom which is damped by a squeezed vacuum shows striking differences from the spectrum for ordinary resonance fluorescence. For strong coherent driving fields the Mollow triplet depends on the relative phase of the driving field and the squeezed vacuum field. The central peak may have either subnatural linewidth or supernatural linewidth depending on this phase. The mean atomic polarization also shows a phase sensitivity.

  2. A Two-Level Sensorless MPPT Strategy Using SRF-PLL on a PMSG Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Amina Echchaachouai

    2017-01-01

    Full Text Available In this paper, a two-level sensorless Maximum Power Point Tracking (MPPT strategy is presented for a variable speed Wind Energy Conversion System (WECS. The proposed system is composed of a wind turbine, a direct-drive Permanent Magnet Synchronous Generator (PMSG and a three phase controlled rectifier connected to a DC load. The realised generator output power maximization analysis justifies the use of the Field Oriented Control (FOC giving the six Pulse Width Modulation (PWM signals to the active rectifier. The generator rotor speed and position required by the FOC and the sensorless MPPT are estimated using a Synchronous Reference Frame Phase Locked Loop (SRF-PLL. The MPPT strategy used consists of two levels, the first level is a power regulation loop and the second level is an extremum seeking bloc generating the coefficient gathering the turbine characteristics. Experimental results validated on a hardware test setup using a DSP digital board (dSPACE 1104 are presented. Figures illustrating the estimated speed and angle confirm that the SRF-PLL is able to give an estimated speed and angle which closely follow the real ones. Also, the power at the DC load and the power at the generator output indicate that the MPPT gives optimum extracted power. Finally, other results show the effectiveness of the adopted approach in real time applications.

  3. Transverse magnetic field effect on the giant Goos–Hänchen shifts based on a degenerate two-level system

    Science.gov (United States)

    Nasehi, R.

    2018-06-01

    We study the effect of the Goos–Hänchen (GH) shifts through a cavity with degenerate two-level systems in the line of . For this purpose, we focus on the transverse magnetic field (TMF) in a Floquet frame to obtain the giant GH shifts. Physically, the collisional effects of TMF lead to increasing the population trapping in the ground state. However, we demonstrate that the population trapping generates the large negative or positive GH shifts and simultaneously switches from superluminal to subluminal (or vice versa). Also, we investigate the other optical properties such as the longitudinal magnetic field (LMF), which plays an important role in the control of the GH shifts and leads to the generation of new subsystems. In the next step, we evaluate the GH shifts beyond the multi-photon resonance condition by the control of TMF. Moreover, we compute the appearance of negative and positive GH shifts by setting the width of the incident Gaussian beams in the presence of a multi-photon resonance condition. Our results show that superluminal or subluminal light propagation can be simultaneously controlled by adjusting the rates of the TMF and LMF. The significant effects of these factors on the degenerate two-level systems provide different applications such as slow light, optical switches and quantum information storage.

  4. Political legitimacy and European monetary union: contracts, constitutionalism and the normative logic of two-level games

    Science.gov (United States)

    Bellamy, Richard; Weale, Albert

    2015-01-01

    ABSTRACT The crisis of the euro area has severely tested the political authority of the European Union (EU). The crisis raises questions of normative legitimacy both because the EU is a normative order and because the construction of economic and monetary union (EMU) rested upon a theory that stressed the normative value of the depoliticization of money. However, this theory neglected the normative logic of the two-level game implicit in EMU. It also neglected the need for an impartial and publically acceptable constitutional order to acknowledge reasonable disagreements. By contrast, we contend that any reconstruction of the EU's economic constitution has to pay attention to reconciling a European monetary order with the legitimacy of member state governance. The EU requires a two-level contract to meet this standard. Member states must treat each other as equals and be representative of and accountable to their citizens on an equitable basis. These criteria entail that the EU's political legitimacy requires a form of demoicracy that we call ‘republican intergovernmentalism’. Only rules that could be acceptable as the product of a political constitution among the peoples of Europe can ultimately meet the required standards of political legitimacy. Such a political constitution could be brought about through empowering national parliaments in EU decision-making. PMID:26924935

  5. Experimental study of magnetocaloric effect in the two-level quantum system KTm(MoO4)2

    Science.gov (United States)

    Tarasenko, R.; Tkáč, V.; Orendáčová, A.; Orendáč, M.; Valenta, J.; Sechovský, V.; Feher, A.

    2018-05-01

    KTm(MoO4)2 belongs to the family of binary alkaline rare-earth molybdates. This compound can be considered to be an almost ideal quantum two-level system at low temperatures. Magnetocaloric properties of KTm(MoO4)2 single crystals were investigated using specific heat and magnetization measurement in the magnetic field applied along the easy axis. Large conventional magnetocaloric effect (-ΔSM ≈ 10.3 J/(kg K)) was observed in the magnetic field of 5 T in a relatively wide temperature interval. The isothermal magnetic entropy change of about 8 J/(kgK) has been achieved already for the magnetic field of 2 T. Temperature dependence of the isothermal entropy change under different magnetic fields is in good agreement with theoretical predictions for a quantum two-level system with Δ ≈ 2.82 cm-1. Investigation of magnetocaloric properties of KTm(MoO4)2 suggests that the studied system can be considered as a good material for magnetic cooling at low temperatures.

  6. Can centralized sanctioning promote trust in social dilemmas? A two-level trust game with incomplete information.

    Science.gov (United States)

    Wang, Raymond Yu; Ng, Cho Nam

    2015-01-01

    The problem of trust is a paradigmatic social dilemma. Previous literature has paid much academic attention on effects of peer punishment and altruistic third-party punishment on trust and human cooperation in dyadic interactions. However, the effects of centralized sanctioning institutions on decentralized reciprocity in hierarchical interactions remain to be further explored. This paper presents a formal two-level trust game with incomplete information which adds an authority as a strategic purposive actor into the traditional trust game. This model allows scholars to examine the problem of trust in more complex game theoretic configurations. The analysis demonstrates how the centralized institutions might change the dynamics of reciprocity between the trustor and the trustee. Findings suggest that the sequential equilibria of the newly proposed two-level model simultaneously include the risk of placing trust for the trustor and the temptation of short-term defection for the trustee. Moreover, they have shown that even a slight uncertainty about the type of the newly introduced authority might facilitate the establishment of trust and reciprocity in social dilemmas.

  7. Can centralized sanctioning promote trust in social dilemmas? A two-level trust game with incomplete information.

    Directory of Open Access Journals (Sweden)

    Raymond Yu Wang

    Full Text Available The problem of trust is a paradigmatic social dilemma. Previous literature has paid much academic attention on effects of peer punishment and altruistic third-party punishment on trust and human cooperation in dyadic interactions. However, the effects of centralized sanctioning institutions on decentralized reciprocity in hierarchical interactions remain to be further explored. This paper presents a formal two-level trust game with incomplete information which adds an authority as a strategic purposive actor into the traditional trust game. This model allows scholars to examine the problem of trust in more complex game theoretic configurations. The analysis demonstrates how the centralized institutions might change the dynamics of reciprocity between the trustor and the trustee. Findings suggest that the sequential equilibria of the newly proposed two-level model simultaneously include the risk of placing trust for the trustor and the temptation of short-term defection for the trustee. Moreover, they have shown that even a slight uncertainty about the type of the newly introduced authority might facilitate the establishment of trust and reciprocity in social dilemmas.

  8. An Economic Order Quantity Model with Completely Backordering and Nondecreasing Demand under Two-Level Trade Credit

    Directory of Open Access Journals (Sweden)

    Zohreh Molamohamadi

    2014-01-01

    Full Text Available In the traditional inventory system, it was implicitly assumed that the buyer pays to the seller as soon as he receives the items. In today’s competitive industry, however, the seller usually offers the buyer a delay period to settle the account of the goods. Not only the seller but also the buyer may apply trade credit as a strategic tool to stimulate his customers’ demands. This paper investigates the effects of the latter policy, two-level trade credit, on a retailer’s optimal ordering decisions within the economic order quantity framework and allowable shortages. Unlike most of the previous studies, the demand function of the customers is considered to increase with time. The objective of the retailer’s inventory model is to maximize the profit. The replenishment decisions optimally are obtained using genetic algorithm. Two special cases of the proposed model are discussed and the impacts of parameters on the decision variables are finally investigated. Numerical examples demonstrate the profitability of the developed two-level supply chain with backorder.

  9. Political legitimacy and European monetary union: contracts, constitutionalism and the normative logic of two-level games.

    Science.gov (United States)

    Bellamy, Richard; Weale, Albert

    2015-02-07

    The crisis of the euro area has severely tested the political authority of the European Union (EU). The crisis raises questions of normative legitimacy both because the EU is a normative order and because the construction of economic and monetary union (EMU) rested upon a theory that stressed the normative value of the depoliticization of money. However, this theory neglected the normative logic of the two-level game implicit in EMU. It also neglected the need for an impartial and publically acceptable constitutional order to acknowledge reasonable disagreements. By contrast, we contend that any reconstruction of the EU's economic constitution has to pay attention to reconciling a European monetary order with the legitimacy of member state governance. The EU requires a two-level contract to meet this standard. Member states must treat each other as equals and be representative of and accountable to their citizens on an equitable basis. These criteria entail that the EU's political legitimacy requires a form of demoi cracy that we call 'republican intergovernmentalism'. Only rules that could be acceptable as the product of a political constitution among the peoples of Europe can ultimately meet the required standards of political legitimacy. Such a political constitution could be brought about through empowering national parliaments in EU decision-making.

  10. Matter-wave scattering and guiding by atomic arrays

    International Nuclear Information System (INIS)

    Vaishnav, J. Y.; Walls, J. D.; Apratim, M.; Heller, E. J.

    2007-01-01

    We investigate the possibility that linear arrays of atoms can guide matter waves, much as fiber optics guide light. We model the atomic line as a quasi-one-dimensional array of s-wave point scatterers embedded in two-dimensions. Our theoretical study reveals how matter-wave guiding arises from the interplay of scattering phenomena with bands and conduction along the array. We discuss the conditions under which a straight or curved array of atoms can guide a beam focused at one end of the array

  11. Atomic fountain and applications

    International Nuclear Information System (INIS)

    Rawat, H.S.

    2000-01-01

    An overview of the development of working of MOT along with the basic principle of laser atom cooling and trapping is given. A technique to separate the cooled and trapped atoms from the MOT using atomic fountain technique will also be covered. The widely used technique for atomic fountain is, first to cool and trap the neutral atoms in MOT and then launch them in the vertical direction, using moving molasses technique. Using 133 Cs atomic fountain clock, time improvement of 2 to 3 order of magnitude over a conventional 133 Cs atomic clock has been observed

  12. Interferometry with atoms

    International Nuclear Information System (INIS)

    Helmcke, J.; Riehle, F.; Witte, A.; Kisters, T.

    1992-01-01

    Physics and experimental results of atom interferometry are reviewed and several realizations of atom interferometers are summarized. As a typical example of an atom interferometer utilizing the internal degrees of freedom of the atom, we discuss the separated field excitation of a calcium atomic beam using four traveling laser fields and demonstrate the Sagnac effect in a rotating interferometer. The sensitivity of this interferometer can be largely increased by use of slow atoms with narrow velocity distribution. We therefore furthermore report on the preparation of a laser cooled and deflected calcium atomic beam. (orig.)

  13. Secure smart embedded devices, platforms and applications

    CERN Document Server

    Markantonakis, Konstantinos

    2013-01-01

    New generations of IT users are increasingly abstracted from the underlying devices and platforms that provide and safeguard their services. As a result they may have little awareness that they are critically dependent on the embedded security devices that are becoming pervasive in daily modern life. Secure Smart Embedded Devices, Platforms and Applications provides a broad overview of the many security and practical issues of embedded devices, tokens, and their operation systems, platforms and main applications. It also addresses a diverse range of industry/government initiatives and consider

  14. Two diverse models of embedding class one

    Science.gov (United States)

    Kuhfittig, Peter K. F.

    2018-05-01

    Embedding theorems have continued to be a topic of interest in the general theory of relativity since these help connect the classical theory to higher-dimensional manifolds. This paper deals with spacetimes of embedding class one, i.e., spacetimes that can be embedded in a five-dimensional flat spacetime. These ideas are applied to two diverse models, a complete solution for a charged wormhole admitting a one-parameter group of conformal motions and a new model to explain the flat rotation curves in spiral galaxies without the need for dark matter.

  15. The art of designing embedded systems

    CERN Document Server

    Ganssle, Jack G

    2000-01-01

    Art of Designing Embedded Systems is apart primer and part reference, aimed at practicing embedded engineers, whether working on the code or the hardware design. Embedded systems suffer from a chaotic, ad hoc development process. This books lays out a very simple seven-step plan to get firmware development under control. There are no formal methodologies to master; the ideas are immediately useful. Most designers are unaware that code complexity grows faster than code size. This book shows a number of ways to linearize the complexity/size curve and get products out faster

  16. Embedded Solenoid Transformer for Power Conversion

    DEFF Research Database (Denmark)

    2015-01-01

    A resonant power converter for operation in the radio frequency range, preferably in the VHF, comprises at least one PCB-embedded transformer. The transformer is configured for radio frequency operation and comprises a printed circuit board defining a horizontal plane, the printed circuit board...... comprising at least two horizontal conductive layers separated by an isolating layer, a first embedded solenoid forming a primary winding of the transformer and a second embedded solenoid being arranged parallel to the first solenoid and forming a secondary winding of the transformer, wherein the first...

  17. Radiative processes of two entangled atoms in cosmic string spacetime

    Science.gov (United States)

    Cai, Huabing; Ren, Zhongzhou

    2018-01-01

    We investigate the radiative processes of two static two-level atoms in a maximally entangled state coupled to vacuum electromagnetic field in the cosmic string spacetime. We find that the decay rate from the entangled state to the ground state crucially depends on the atomic separation, the polarization directions of the individual atoms, the atom-string distance and the deficit angle induced by the string. As the atom-string distance increases, the decay rate oscillates around the result in Minkowski spacetime and the amplitude gradually decreases. The oscillation is more severe for larger planar angle deficit. We analyze the decay rate in different circumstances such as near zone and specific polarization cases. Some comparisons between symmetric and antisymmetric states are performed. By contrast with the case in Minkowski spacetime, we can reveal the effects of the cosmic string on the radiative properties of the entangled atoms.

  18. AdS2 models in an embedding superspace

    International Nuclear Information System (INIS)

    McKeon, D.G.C.; Sherry, T.N.

    2003-01-01

    An embedding superspace, whose bosonic part is the flat (2+1)-dimensional embedding space for AdS 2 , is introduced. Superfields and several supersymmetric models are examined in the embedded AdS 2 superspace

  19. Influence of the virtual photon field on the squeezing properties of an atom laser

    International Nuclear Information System (INIS)

    Jian-Gang, Zhao; Chang-Yong, Sun; Ling-Hua, Wen; Bao-Long, Liang

    2009-01-01

    This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose–Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser

  20. Three-atom clusters

    International Nuclear Information System (INIS)

    Pen'kov, F.M.

    1998-01-01

    The Born-Oppenheimer approximation is used to obtain an equation for the effective interaction in three atoms bound by a single electron. For low binding energies in an 'electron + atom' pair, long-range forces arise between the atoms, leading to bound states when the size of the three-atom cluster is a few tens of angstrom. A system made of alkali-metal atoms is considered as an example

  1. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  2. Supply chain model with price- and trade credit-sensitive demand under two-level permissible delay in payments

    Science.gov (United States)

    Giri, B. C.; Maiti, T.

    2013-05-01

    This article develops a single-manufacturer and single-retailer supply chain model under two-level permissible delay in payments when the manufacturer follows a lot-for-lot policy in response to the retailer's demand. The manufacturer offers a trade credit period to the retailer with the contract that the retailer must share a fraction of the profit earned during the trade credit period. On the other hand, the retailer provides his customer a partial trade credit which is less than that of the manufacturer. The demand at the retailer is assumed to be dependent on the selling price and the trade credit period offered to the customers. The average net profit of the supply chain is derived and an algorithm for finding the optimal solution is developed. Numerical examples are given to demonstrate the coordination policy of the supply chain and examine the sensitivity of key model-parameters.

  3. LCL filter design for three-phase two-level power factor correction using line impedance stabilization network

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Nymand, Morten

    2016-01-01

    This paper presents LCL filter design method for three-phase two-level power factor correction (PFC) using line impedance stabilization network (LISN). A straightforward LCL filter design along with variation in grid impedance is not simply achievable and inevitably lead to an iterative solution...... for filter. By introducing of fast power switches for PFC applications such as silicon-carbide, major current harmonics around the switching frequency drops in the region that LISN can actively provide well-defined impedance for measuring the harmonics (i.e. 9 kHz- 30MHz). Therefore, LISN can be replaced...... is derived using the current ripple behavior of converter-side inductor. The grid-side inductor is achieved as a function of LISN impedance to fulfill the grid regulation. To verify the analyses, an LCL filter is designed for a 5 kW SiC-based PFC. The simulation and experimental results support the validity...

  4. Loschmidt echo of a two-level qubit coupled to nonuniform anisotropic XY chains in a transverse field

    International Nuclear Information System (INIS)

    Zhong Ming; Tong Peiqing

    2011-01-01

    The Loschmidt echo (LE) of a central two-level qubit coupled to nonuniform anisotropic XY chains in a transverse field is studied. A general formula for LE is derived, which we use to discuss the influence of the criticality of the environment on LE. It is found that for the periodic XY chain the behaviors of LE in the vicinity of the critical points are similar to those of the uniform case. It is different for the disordered transverse Ising chains. For the aperiodic chains, if the surrounding systems are bounded chains, the behaviors of LE are similar to those of the uniform case, while if the surrounding systems are unbounded chains, they are similar to those of the disordered case.

  5. The EPQ model under conditions of two levels of trade credit and limited storage capacity in supply chain management

    Science.gov (United States)

    Chung, Kun-Jen

    2013-09-01

    An inventory problem involves a lot of factors influencing inventory decisions. To understand it, the traditional economic production quantity (EPQ) model plays rather important role for inventory analysis. Although the traditional EPQ models are still widely used in industry, practitioners frequently question validities of assumptions of these models such that their use encounters challenges and difficulties. So, this article tries to present a new inventory model by considering two levels of trade credit, finite replenishment rate and limited storage capacity together to relax the basic assumptions of the traditional EPQ model to improve the environment of the use of it. Keeping in mind cost-minimisation strategy, four easy-to-use theorems are developed to characterise the optimal solution. Finally, the sensitivity analyses are executed to investigate the effects of the various parameters on ordering policies and the annual total relevant costs of the inventory system.

  6. Dynamics of a Landau-Zener transitions in a two-level system driven by a dissipative environment

    Science.gov (United States)

    Ateuafack, M. E.; Diffo, J. T.; Fai, L. C.

    2016-02-01

    The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.

  7. Dynamics of a Landau–Zener transitions in a two-level system driven by a dissipative environment

    Energy Technology Data Exchange (ETDEWEB)

    Ateuafack, M.E., E-mail: esouamath@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Diffo, J.T., E-mail: diffojaures@yahoo.com [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Department of Physics, Higher Teachers' Training College, The University of Maroua, PO Box 55 Maroua (Cameroon); Fai, L.C., E-mail: corneliusfai@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon)

    2016-02-15

    The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.

  8. An acceleration of the characteristics by a space-angle two-level method using surface discontinuity factors

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, G. [Commissariat a l' Energie Atomique, CEA de Saclay, DM2S/SERMA/LENR, 91191, Gif-sur-Yvette (France)

    2006-07-01

    We present a non-linear space-angle two-level acceleration scheme for the method of the characteristics (MOC). To the fine level on which the MOC transport calculation is performed, we associate a more coarsely discretized phase space in which a low-order problem is solved as an acceleration step. Cross sections on the coarse level are obtained by a flux-volume homogenisation technique, which entails the non-linearity of the acceleration. Discontinuity factors per surface are introduced as additional degrees of freedom on the coarse level in order to ensure the equivalence of the heterogeneous and the homogenised problem. After each fine transport iteration, a low-order transport problem is iteratively solved on the homogenised grid. The solution of this problem is then used to correct the angular moments of the flux resulting from the previous free transport sweep. Numerical tests for a given benchmark have been performed. Results are discussed. (authors)

  9. An acceleration of the characteristics by a space-angle two-level method using surface discontinuity factors

    International Nuclear Information System (INIS)

    Grassi, G.

    2006-01-01

    We present a non-linear space-angle two-level acceleration scheme for the method of the characteristics (MOC). To the fine level on which the MOC transport calculation is performed, we associate a more coarsely discretized phase space in which a low-order problem is solved as an acceleration step. Cross sections on the coarse level are obtained by a flux-volume homogenisation technique, which entails the non-linearity of the acceleration. Discontinuity factors per surface are introduced as additional degrees of freedom on the coarse level in order to ensure the equivalence of the heterogeneous and the homogenised problem. After each fine transport iteration, a low-order transport problem is iteratively solved on the homogenised grid. The solution of this problem is then used to correct the angular moments of the flux resulting from the previous free transport sweep. Numerical tests for a given benchmark have been performed. Results are discussed. (authors)

  10. A Two-level-games Analysis of AFTA Agreements: What Caused ASEAN States to Move towards Economic Integration?

    Directory of Open Access Journals (Sweden)

    Yi-hung Chiou

    2010-04-01

    Full Text Available The goal of this article is to investigate the conditions under which ASEAN states are more likely to pursue regional economic integration, namely, a series of ASEAN Free Trade Area (AFTA agreements/ protocols. Adopting Putnam’s two-level-games model, this article examines the influences of domestic politics, political elites’ preferences, economic performance, and external impacts. Through the construction of a set of hypotheses, this article investigates five AFTA agreements/ protocols and the conditions of ASEAN states during the 1992–2003 period. The findings indicate that political leaders’ preferences have played a pivotal role in the development of the AFTA. Economic performance and domestic support in individual states has also affected the AFTA. The close link between AFTA agreements and external impacts reveals that the AFTA’s inherent nature is defensive.

  11. Embedded Face Detection and Recognition

    Directory of Open Access Journals (Sweden)

    Göksel Günlü

    2012-10-01

    Full Text Available The need to increase security in open or public spaces has in turn given rise to the requirement to monitor these spaces and analyse those images on-site and on-time. At this point, the use of smart cameras – of which the popularity has been increasing – is one step ahead. With sensors and Digital Signal Processors (DSPs, smart cameras generate ad hoc results by analysing the numeric images transmitted from the sensor by means of a variety of image-processing algorithms. Since the images are not transmitted to a distance processing unit but rather are processed inside the camera, it does not necessitate high-bandwidth networks or high processor powered systems; it can instantaneously decide on the required access. Nonetheless, on account of restricted memory, processing power and overall power, image processing algorithms need to be developed and optimized for embedded processors. Among these algorithms, one of the most important is for face detection and recognition. A number of face detection and recognition methods have been proposed recently and many of these methods have been tested on general-purpose processors. In smart cameras – which are real-life applications of such methods – the widest use is on DSPs. In the present study, the Viola-Jones face detection method – which was reported to run faster on PCs – was optimized for DSPs; the face recognition method was combined with the developed sub-region and mask-based DCT (Discrete Cosine Transform. As the employed DSP is a fixed-point processor, the processes were performed with integers insofar as it was possible. To enable face recognition, the image was divided into sub-regions and from each sub-region the robust coefficients against disruptive elements – like face expression, illumination, etc. – were selected as the features. The discrimination of the selected features was enhanced via LDA (Linear Discriminant Analysis and then employed for recognition. Thanks to its

  12. Multidimensional artificial field embedding with spatial sensitivity

    CSIR Research Space (South Africa)

    Lunga, D

    2013-06-01

    Full Text Available Multidimensional embedding is a technique useful for characterizing spectral signature relations in hyperspectral images. However, such images consist of disjoint similar spectral classes that are spatially sensitive, thus presenting challenges...

  13. Costs and benefits of embedded generation

    International Nuclear Information System (INIS)

    1999-11-01

    This project sought to evaluate the costs and benefits of embedded generation in the light of the UK government's consultation paper on the future of green generation, the government's aim to increase the levels of generation from renewable energy sources and cogeneration, the current Review of the Electricity Trading Arrangements, and the form of the Distribution Price Control. Definitions are given for embedded, centrally dispatched, and pooled generation, and licensed suppliers, and commercial and economic values. The commercial and economic value of embedded generation is examined in terms of generation prices, costs to electrical suppliers, losses (electrical, transmission, distribution), and effects on the national grid and distribution network. Diagrams showing the cost elements of trading through the Pool and the elements that are avoided by non-Pool embedded generator trading are presented

  14. Time-Scale Invariant Audio Data Embedding

    Directory of Open Access Journals (Sweden)

    Mansour Mohamed F

    2003-01-01

    Full Text Available We propose a novel algorithm for high-quality data embedding in audio. The algorithm is based on changing the relative length of the middle segment between two successive maximum and minimum peaks to embed data. Spline interpolation is used to change the lengths. To ensure smooth monotonic behavior between peaks, a hybrid orthogonal and nonorthogonal wavelet decomposition is used prior to data embedding. The possible data embedding rates are between 20 and 30 bps. However, for practical purposes, we use repetition codes, and the effective embedding data rate is around 5 bps. The algorithm is invariant after time-scale modification, time shift, and time cropping. It gives high-quality output and is robust to mp3 compression.

  15. Embedding Moodle into Ubiquitous Computing Environments

    NARCIS (Netherlands)

    Glahn, Christian; Specht, Marcus

    2010-01-01

    Glahn, C., & Specht, M. (2010). Embedding Moodle into Ubiquitous Computing Environments. In M. Montebello, et al. (Eds.), 9th World Conference on Mobile and Contextual Learning (MLearn2010) (pp. 100-107). October, 19-22, 2010, Valletta, Malta.

  16. Apparatuses And Systems For Embedded Thermoelectric Generators

    KAUST Repository

    Hussain, Muhammad M.

    2013-08-08

    An apparatus and a system for embedded thermoelectric generators are disclosed. In one embodiment, the apparatus is embedded in an interface where the ambient temperatures on two sides of the interface are different. In one embodiment, the apparatus is fabricated with the interface in integrity as a unitary piece. In one embodiment, the apparatus includes a first thermoelectric material embedded through the interface. The apparatus further includes a second thermoelectric material embedded through the interface. The first thermoelectric material is electrically coupled to the second thermoelectric material. In one embodiment, the apparatus further includes an output structure coupled to the first thermoelectric material and the second thermoelectric material and configured to output a voltage.

  17. Apparatuses And Systems For Embedded Thermoelectric Generators

    KAUST Repository

    Hussain, Muhammad M.; Inayat, Salman Bin; Smith, Casey Eben

    2013-01-01

    An apparatus and a system for embedded thermoelectric generators are disclosed. In one embodiment, the apparatus is embedded in an interface where the ambient temperatures on two sides of the interface are different. In one embodiment, the apparatus is fabricated with the interface in integrity as a unitary piece. In one embodiment, the apparatus includes a first thermoelectric material embedded through the interface. The apparatus further includes a second thermoelectric material embedded through the interface. The first thermoelectric material is electrically coupled to the second thermoelectric material. In one embodiment, the apparatus further includes an output structure coupled to the first thermoelectric material and the second thermoelectric material and configured to output a voltage.

  18. Embedded High Performance Scalable Computing Systems

    National Research Council Canada - National Science Library

    Ngo, David

    2003-01-01

    The Embedded High Performance Scalable Computing Systems (EHPSCS) program is a cooperative agreement between Sanders, A Lockheed Martin Company and DARPA that ran for three years, from Apr 1995 - Apr 1998...

  19. Design of a Two-level Adaptive Multi-Agent System for Malaria Vectors driven by an ontology

    Directory of Open Access Journals (Sweden)

    Etang Josiane

    2007-07-01

    Full Text Available Abstract Background The understanding of heterogeneities in disease transmission dynamics as far as malaria vectors are concerned is a big challenge. Many studies while tackling this problem don't find exact models to explain the malaria vectors propagation. Methods To solve the problem we define an Adaptive Multi-Agent System (AMAS which has the property to be elastic and is a two-level system as well. This AMAS is a dynamic system where the two levels are linked by an Ontology which allows it to function as a reduced system and as an extended system. In a primary level, the AMAS comprises organization agents and in a secondary level, it is constituted of analysis agents. Its entry point, a User Interface Agent, can reproduce itself because it is given a minimum of background knowledge and it learns appropriate "behavior" from the user in the presence of ambiguous queries and from other agents of the AMAS in other situations. Results Some of the outputs of our system present a series of tables, diagrams showing some factors like Entomological parameters of malaria transmission, Percentages of malaria transmission per malaria vectors, Entomological inoculation rate. Many others parameters can be produced by the system depending on the inputted data. Conclusion Our approach is an intelligent one which differs from statistical approaches that are sometimes used in the field. This intelligent approach aligns itself with the distributed artificial intelligence. In terms of fight against malaria disease our system offers opportunities of reducing efforts of human resources who are not obliged to cover the entire territory while conducting surveys. Secondly the AMAS can determine the presence or the absence of malaria vectors even when specific data have not been collected in the geographical area. In the difference of a statistical technique, in our case the projection of the results in the field can sometimes appeared to be more general.

  20. A preventive maintenance model with a two-level inspection policy based on a three-stage failure process

    International Nuclear Information System (INIS)

    Wang, Wenbin; Zhao, Fei; Peng, Rui

    2014-01-01

    Inspection is always an important preventive maintenance (PM) activity and can have different depths and cover all or part of plant systems. This paper introduces a two-level inspection policy model for a single component plant system based on a three-stage failure process. Such a failure process divides the system′s life into three stages: good, minor defective and severe defective stages. The first level of inspection, the minor inspection, can only identify the minor defective stage with a certain probability, but can always reveal the severe defective stage. The major inspection can however identify both defective stages perfectly. Once the system is found to be in the minor defective stage, a shortened inspection interval is adopted. If however the system is found to be in the severe defective stage, we may delay the maintenance action if the time to the next planned PM window is less than a threshold level, but otherwise, replace immediately. This corresponds to the well adopted maintenance policy in practice such as periodic inspections with planned PMs. A numerical example is presented to demonstrate the proposed model by comparing with other models. - Highlights: • The system′s deterioration goes through a three-stage process, namely, normal, minor defective and severe defective. • Two levels of inspections are proposed, e.g., minor and major inspections. • Once the minor defective stage is found, instead of taking a maintenance action, a shortened inspection interval is recommended. • When the severe defective stage is found, we delay the maintenance according to the threshold to the next PM. • The decision variables are the inspection intervals and the threshold to PM