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Sample records for coulomb integral transform

  1. Gaussian and finite-element Coulomb method for the fast evaluation of Coulomb integrals

    NASA Astrophysics Data System (ADS)

    Kurashige, Yuki; Nakajima, Takahito; Hirao, Kimihiko

    2007-04-01

    The authors propose a new linear-scaling method for the fast evaluation of Coulomb integrals with Gaussian basis functions called the Gaussian and finite-element Coulomb (GFC) method. In this method, the Coulomb potential is expanded in a basis of mixed Gaussian and finite-element auxiliary functions that express the core and smooth Coulomb potentials, respectively. Coulomb integrals can be evaluated by three-center one-electron overlap integrals among two Gaussian basis functions and one mixed auxiliary function. Thus, the computational cost and scaling for large molecules are drastically reduced. Several applications to molecular systems show that the GFC method is more efficient than the analytical integration approach that requires four-center two-electron repulsion integrals. The GFC method realizes a near linear scaling for both one-dimensional alanine α-helix chains and three-dimensional diamond pieces.

  2. Gaussian and finite-element Coulomb method for the fast evaluation of Coulomb integrals.

    PubMed

    Kurashige, Yuki; Nakajima, Takahito; Hirao, Kimihiko

    2007-04-14

    The authors propose a new linear-scaling method for the fast evaluation of Coulomb integrals with Gaussian basis functions called the Gaussian and finite-element Coulomb (GFC) method. In this method, the Coulomb potential is expanded in a basis of mixed Gaussian and finite-element auxiliary functions that express the core and smooth Coulomb potentials, respectively. Coulomb integrals can be evaluated by three-center one-electron overlap integrals among two Gaussian basis functions and one mixed auxiliary function. Thus, the computational cost and scaling for large molecules are drastically reduced. Several applications to molecular systems show that the GFC method is more efficient than the analytical integration approach that requires four-center two-electron repulsion integrals. The GFC method realizes a near linear scaling for both one-dimensional alanine alpha-helix chains and three-dimensional diamond pieces. PMID:17444700

  3. Poisson's equation solution of Coulomb integrals in atoms and molecules

    NASA Astrophysics Data System (ADS)

    Weatherford, Charles A.; Red, Eddie; Joseph, Dwayne; Hoggan, Philip

    The integral bottleneck in evaluating molecular energies arises from the two-electron contributions. These are difficult and time-consuming to evaluate, especially over exponential type orbitals, used here to ensure the correct behaviour of atomic orbitals. In this work, it is shown that the two-centre Coulomb integrals involved can be expressed as one-electron kinetic-energy-like integrals. This is accomplished using the fact that the Coulomb operator is a Green's function of the Laplacian. The ensuing integrals may be further simplified by defining Coulomb forms for the one-electron potential satisfying Poisson's equation therein. A sum of overlap integrals with the atomic orbital energy eigenvalue as a factor is then obtained to give the Coulomb energy. The remaining questions of translating orbitals involved in three and four centre integrals and the evaluation of exchange energy are also briefly discussed. The summation coefficients in Coulomb forms are evaluated using the LU decomposition. This algorithm is highly parallel. The Poisson method may be used to calculate Coulomb energy integrals efficiently. For a single processor, gains of CPU time for a given chemical accuracy exceed a factor of 40. This method lends itself to evaluation on a parallel computer.

  4. Convergence of Feynman integrals in Coulomb gauge QCD

    SciTech Connect

    Andraši, A.; Taylor, J.C.

    2014-12-15

    At 2-loop order, Feynman integrals in the Coulomb gauge are divergent over the internal energy variables. Nevertheless, it is known how to calculate the effective action, provided that the external gluon fields are all transverse. We show that, for the two-gluon Greens function as an example, the method can be extended to include longitudinal external fields. The longitudinal Greens functions appear in the BRST identities. As an intermediate step, we use a flow gauge, which interpolates between the Feynman and Coulomb gauges.

  5. The accuracy of the Gaussian-and-finite-element-Coulomb (GFC) method for the calculation of Coulomb integrals

    NASA Astrophysics Data System (ADS)

    Przybytek, Michal; Helgaker, Trygve

    2013-08-01

    We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γH = 2) and eight (γ1st = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (α _min^G=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d4 with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step—namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems

  6. The accuracy of the Gaussian-and-finite-element-Coulomb (GFC) method for the calculation of Coulomb integrals.

    PubMed

    Przybytek, Michal; Helgaker, Trygve

    2013-08-01

    We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γ(H) = 2) and eight (γ(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (αmin (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems

  7. Evaluation of multicenter one-electron integrals of noninteger u screened Coulomb type potentials and their derivatives over noninteger n Slater orbitals.

    PubMed

    Guseinov, I I; Mamedov, B A

    2004-07-22

    Multicenter integrals over noninteger n Slater type orbitals with integer and noninteger values of indices u of screened Coulomb type potentials, f(u)(eta,r)=r(u-1)e(-etar), and their first and second derivatives with respect to Cartesian coordinates of the nuclei of a molecule are described. Using complete orthonormal sets of Psi(alpha) exponential type orbitals and rotation transformation of two-center overlap integrals, these integrals are expressed through the noncentral potential functions depending on the molecular auxiliary functions A(k) and B(k). The series expansion formulas derived for molecular integrals of screened Coulomb potentials and their derivatives are especially useful for the computation of multicenter electronic attraction, electric field, and electric field gradient integrals. The convergence of series is tested for arbitrary values of parameters of potentials and orbitals. PMID:15260714

  8. Towards a Faddeev-AGS description of (d, p) reactions with heavy nuclei: Regularizing integrals with Coulomb functions.

    NASA Astrophysics Data System (ADS)

    Eremenko, V.; Hlophe, L.; Elster, Ch.; Nunes, F. M.; Thompson, I. J.; Arbanas, G.; Escher, J. E.

    2016-03-01

    The repulsive Coulomb force poses severe challenges when describing (d, p) reactions for highly charged nuclei as a three-body problem. Casting Faddeev-AGS equations in a Coulomb basis avoids introducing screening of the Coulomb force. However, momentum space partial-wave t-matrix elements need to be evaluated in this basis. When those t-matrices are separable, the evaluation requires the folding of a form factor, depending on one momentum variable, with a momentum space partial-wave Coulomb function, which has a singular behavior at the external momentum q. We developed an improved regularization scheme to calculate Coulomb distorted form factors as the integral over the Coulomb function and complex nuclear form factors.

  9. Generating functions via integral transforms

    NASA Astrophysics Data System (ADS)

    Ben Cheikh, Y.; Lamiri, I.

    2007-07-01

    In this paper, we use some integral transforms to derive, for a polynomial sequence {Pn(x)}n[greater-or-equal, slanted]0, generating functions of the type , starting from a generating function of type , where {[gamma]n}n[greater-or-equal, slanted]0 is a real numbers sequence independent on x and t. That allows us to unify the treatment of a generating function problem for many well-known polynomial sequences in the literature.

  10. Integrable generalizations of oscillator and Coulomb systems via action-angle variables

    NASA Astrophysics Data System (ADS)

    Hakobyan, T.; Lechtenfeld, O.; Nersessian, A.; Saghatelian, A.; Yeghikyan, V.

    2012-01-01

    Oscillator and Coulomb systems on N-dimensional spaces of constant curvature can be generalized by replacing their angular degrees of freedom with a compact integrable (N-1)-dimensional system. We present the action-angle formulation of such models in terms of the radial degree of freedom and the action-angle variables of the angular subsystem. As an example, we construct the spherical and pseudospherical generalization of the two-dimensional superintegrable models introduced by Tremblay, Turbiner and Winternitz and by Post and Winternitz. We demonstrate the superintegrability of these systems and give their hidden constant of motion.

  11. Properties of the linear canonical integral transformation.

    PubMed

    Alieva, Tatiana; Bastiaans, Martin J

    2007-11-01

    We provide a general expression and different classification schemes for the general two-dimensional canonical integral transformations that describe the propagation of coherent light through lossless first-order optical systems. Main theorems for these transformations, such as shift, scaling, derivation, etc., together with the canonical integral transforms of selected functions, are derived. PMID:17975592

  12. Off-shell Jost solutions for Coulomb and Coulomb-like interactions in all partial waves

    SciTech Connect

    Laha, U.; Bhoi, J.

    2013-01-15

    By exploiting the theory of ordinary differential equations, with judicious use of boundary conditions, interacting Green's functions and their integral transforms together with certain properties of higher transcendental functions, useful analytical expressions for the off-shell Jost solutions for motion in Coulomb and Coulomb-nuclear potentials are derived in maximal reduced form through different approaches to the problem in the representation space. The exact analytical expressions for the off-shell Jost solutions for Coulomb and Coulomb-like potentials are believed to be useful for the description of the charged particle scattering/reaction processes.

  13. Interference between Coulombic and CT-mediated couplings in molecular aggregates: H- to J-aggregate transformation in perylene-based π-stacks

    SciTech Connect

    Hestand, Nicholas J.; Spano, Frank C.

    2015-12-28

    The spectroscopic differences between J and H-aggregates are traditionally attributed to the spatial dependence of the Coulombic coupling, as originally proposed by Kasha. However, in tightly packed molecular aggregates wave functions on neighboring molecules overlap, leading to an additional charge transfer (CT) mediated exciton coupling with a vastly different spatial dependence. The latter is governed by the nodal patterns of the molecular LUMOs and HOMOs from which the electron (t{sub e}) and hole (t{sub h}) transfer integrals derive. The sign of the CT-mediated coupling depends on the sign of the product t{sub e}t{sub h} and is therefore highly sensitive to small (sub-Angstrom) transverse displacements or slips. Given that Coulombic and CT-mediated couplings exist simultaneously in tightly packed molecular systems, the interference between the two must be considered when defining J and H-aggregates. Generally, such π-stacked aggregates do not abide by the traditional classification scheme of Kasha: for example, even when the Coulomb coupling is strong the presence of a similarly strong but destructively interfering CT-mediated coupling results in “null-aggregates” which spectroscopically resemble uncoupled molecules. Based on a Frenkel/CT Holstein Hamiltonian that takes into account both sources of electronic coupling as well as intramolecular vibrations, vibronic spectral signatures are developed for integrated Frenkel/CT systems in both the perturbative and resonance regimes. In the perturbative regime, the sign of the lowest exciton band curvature, which rigorously defines J and H-aggregation, is directly tracked by the ratio of the first two vibronic peak intensities. Even in the resonance regime, the vibronic ratio remains a useful tool to evaluate the J or H nature of the system. The theory developed is applied to the reversible H to J-aggregate transformations recently observed in several perylene bisimide systems.

  14. Interference between Coulombic and CT-mediated couplings in molecular aggregates: H- to J-aggregate transformation in perylene-based π-stacks

    NASA Astrophysics Data System (ADS)

    Hestand, Nicholas J.; Spano, Frank C.

    2015-12-01

    The spectroscopic differences between J and H-aggregates are traditionally attributed to the spatial dependence of the Coulombic coupling, as originally proposed by Kasha. However, in tightly packed molecular aggregates wave functions on neighboring molecules overlap, leading to an additional charge transfer (CT) mediated exciton coupling with a vastly different spatial dependence. The latter is governed by the nodal patterns of the molecular LUMOs and HOMOs from which the electron (te) and hole (th) transfer integrals derive. The sign of the CT-mediated coupling depends on the sign of the product teth and is therefore highly sensitive to small (sub-Angstrom) transverse displacements or slips. Given that Coulombic and CT-mediated couplings exist simultaneously in tightly packed molecular systems, the interference between the two must be considered when defining J and H-aggregates. Generally, such π-stacked aggregates do not abide by the traditional classification scheme of Kasha: for example, even when the Coulomb coupling is strong the presence of a similarly strong but destructively interfering CT-mediated coupling results in "null-aggregates" which spectroscopically resemble uncoupled molecules. Based on a Frenkel/CT Holstein Hamiltonian that takes into account both sources of electronic coupling as well as intramolecular vibrations, vibronic spectral signatures are developed for integrated Frenkel/CT systems in both the perturbative and resonance regimes. In the perturbative regime, the sign of the lowest exciton band curvature, which rigorously defines J and H-aggregation, is directly tracked by the ratio of the first two vibronic peak intensities. Even in the resonance regime, the vibronic ratio remains a useful tool to evaluate the J or H nature of the system. The theory developed is applied to the reversible H to J-aggregate transformations recently observed in several perylene bisimide systems.

  15. Reexamination of the calculation of two-center, two-electron integrals over Slater-type orbitals. I. Coulomb and hybrid integrals.

    PubMed

    Lesiuk, Michał; Moszynski, Robert

    2014-12-01

    In this paper, which constitutes the first part of the series, we consider calculation of two-center Coulomb and hybrid integrals over Slater-type orbitals. General formulas for these integrals are derived with no restrictions on the values of the quantum numbers and nonlinear parameters. Direct integration over the coordinates of one of the electrons leaves us with the set of overlaplike integrals which are evaluated by using two distinct methods. The first one is based on the transformation to the ellipsoidal coordinates system and the second utilizes a recursive scheme for consecutive increase of the angular momenta in the integrand. In both methods simple one-dimensional numerical integrations are used in order to avoid severe digital erosion connected with the straightforward use of the alternative analytical formulas. It is discussed that the numerical integration does not introduce a large computational overhead since the integrands are well-behaved functions, calculated recursively with decent speed. Special attention is paid to the numerical stability of the algorithms. Applicability of the resulting scheme over a large range of the nonlinear parameters is tested on examples of the most difficult integrals appearing in the actual calculations including, at most, 7i-type functions (l=6). PMID:25615232

  16. Transformational Leadership, Integrity, and Power

    ERIC Educational Resources Information Center

    Harrison, Laura M.

    2011-01-01

    Transformational leadership enjoys widespread appeal among student affairs professionals. National Association of Student Personnel Administrators (NASPA) and American College Personnel Association (ACPA) conferences frequently feature speakers who promote transformational leadership's two primary tenets: (1) change is the central purpose of…

  17. Analytically reduced form of multicenter integrals from Gaussian transforms. [in atomic and molecular physics

    NASA Technical Reports Server (NTRS)

    Straton, Jack C.

    1989-01-01

    The four-dimensional Fourier-Feynman transformations previously used in analytically reducing the general class of integrals containing multicenter products of 1s hydrogenic orbitals, Coulomb or Yukawa potentials, and plane waves, are replaced by the one-dimensional Gaussian transformation. This reduces the previously required double-diagonalization of the quadratic form of the multicenter integrals to only one diagonalization, yielding a simpler reduced form of the integral. The present work also extends the result to include all s states and pairs of states with l not equal to zero summed over the m quantum number.

  18. Three-body-continuum Coulomb problem using a compact-kernel-integral-equation approach

    NASA Astrophysics Data System (ADS)

    Silenou Mengoue, M.

    2013-02-01

    We present an approach associated with the Jacobi matrix method to calculate a three-body wave function that describes the double continuum of an atomic two-electron system. In this approach, a symmetrized product of two Coulomb waves is used to describe the asymptotic wave function, while a smooth cutoff function is introduced to the dielectronic potential that enters its integral part in order to have a compact kernel of the corresponding Lippmann-Schwinger-type equation to be solved. As an application, the integral equation for the (e-,e-,He2+) system is solved numerically; the fully fivefold differential cross sections (FDCSs) for (e,3e) processes in helium are presented within the first-order Born approximation. The calculation is performed for a coplanar geometry in which the incident electron is fast (˜6 keV) and for a symmetric energy sharing between both slow ejected electrons at excess energy of 20 eV. The experimental and theoretical FDCSs agree satisfactorily both in shape and in magnitude. Full convergence in terms of the basis size is reached and presented.

  19. Higher-order time integration of Coulomb collisions in a plasma using Langevin equations

    SciTech Connect

    Dimits, A. M.; Cohen, B. I.; Caflisch, R. E.; Rosin, M. S.; Ricketson, L. F.

    2013-02-08

    The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the two fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt1/2)] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. Lastly, this method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.

  20. Path Integral Solution for the Coulomb Potential in a Curved Space of Constant Positive Curvature

    NASA Astrophysics Data System (ADS)

    Aggoun, L.; Bounouioua, N.; Benamira, F.; Guechi, L.

    2016-05-01

    A new path integral treatment of a hydrogen-like atom in a uniformly curved space with a constant positive curvature is presented. By converting the radial path integral into a path integral for the modified Pöschl-Teller potential with the help of the space-time transformation technique, the radial Green's function is expressed in closed form, from which the energy spectrum and the corresponding normalized wave functions of the bound states are extracted. In the limit of vanishing curvature, the Green's function, the energy spectra and the correctly normalized wave functions of bound and scattering states for a standard hydrogen-like atom are found.

  1. A tight distance-dependent estimator for screening three-center Coulomb integrals over Gaussian basis functions

    SciTech Connect

    Hollman, David S.; Schaefer, Henry F.; Valeev, Edward F.

    2015-04-21

    A new estimator for three-center two-particle Coulomb integrals is presented. Our estimator is exact for some classes of integrals and is much more efficient than the standard Schwartz counterpart due to the proper account of distance decay. Although it is not a rigorous upper bound, the maximum degree of underestimation can be controlled by two adjustable parameters. We also give numerical evidence of the excellent tightness of the estimator. The use of the estimator will lead to increased efficiency in reduced-scaling one- and many-body electronic structure theories.

  2. Data integration using color space transforms

    USGS Publications Warehouse

    Feuquay, Jay W.

    1987-01-01

    The demand for increased spatial resolution without sacrificing spectral discrimination can be fulfilled by integration of data from different sensor systems and satellite programs. Data of high spatial resolution are frequently available in panchromatic (black-and-white) form rather than multispectral. Techniques gave been developed to combine the higher resolution panchromatic data with a multispectral data set of lower spatial resolution. The standard method of integration modulates the intensity of the mutispectral with the panchromatic data. A less subjective approach uses an algorithm that describes color in terms of intensity (I), hue (H), and saturation (S). Combinations of high resolution panchromatic data (SPOT panchromatic) and lower resolution multispectral data [Landsat thematic mapper (TM), SPOT XS] have been developed. The SPOT data were acquired on April 3, 1986, and the Landsat TM data were acquired on April 5, 1986. The data sets were registered to each other and the multi-spectral data sets were contrast enhanced. The enhanced multispectral data sets were then transformed from red/green/blue (RGB) color space into IHS space. In each case (TM/SPOT panchromatic and SPOT XS/SPOT panchromatic), the SPOT panchromatic data were remapped on a cumulative histogram percentage basis to match the multispectral "I" data. These remapped SPOT panchromatic data were substituted for the original multispectral "I" and the hybrid IHS data transformed back into RGB space for display. While this technique is experimental and still being refined, the results, to date, indicate that the IHS method will be valuable for generating improved images that effectively present both high resolution spatial digital data and multispectral data.

  3. Analytically reduced form for the class of integrals containing multicenter products of 1s hydrogenic orbitals, Coulomb or Yukawa potentials, and plane waves

    NASA Technical Reports Server (NTRS)

    Straton, Jack C.

    1989-01-01

    The class of integrals containing the product of N 1s hydrogenic orbitals and M Coulomb or Yukawa potentials with m plane waves is investigated analytically. The results obtained by Straton (1989) are extended and generalized. It is shown that the dimensionality of the entire class can be reduced from 3m to M+N-1.

  4. Allied health: integral to transforming health.

    PubMed

    Lizarondo, Lucylynn; Turnbull, Catherine; Kroon, Tracey; Grimmer, Karen; Bell, Alison; Kumar, Saravana; McEvoy, Maureen; Milanese, Steve; Russell, Mary; Sheppard, Lorraine; Walters, Julie; Wiles, Louise

    2016-04-01

    Objective South Australia is taking an innovative step in transforming the way its healthcare is organised and delivered to better manage current and future demands on the health system. In an environment of transforming health services, there are clear opportunities for allied health to assist in determining solutions to various healthcare challenges. A recent opinion piece proposed 10 clinician-driven strategies to assist in maximising value and sustainability of healthcare in Australia. The present study aimed to seek the perspectives of allied health clinicians, educators, researchers, policy makers and managers on these strategies and their relevance to allied health. Methods A survey of allied health practitioners was undertaken to capture their perspectives on the 10 clinician-driven strategies for maximising value and sustainability of healthcare in Australia. Survey findings were then layered with evidence from the literature. Results Highly relevant across allied health are the strategies of discontinuation of low value practices, targeting clinical interventions to those getting greatest benefit, active involvement of patients in shared decision making and self-management and advocating for integrated systems of care. Conclusions Allied health professionals have been involved in the South Australian healthcare system for a prolonged period, but their services are poorly recognised, often overlooked and not greatly supported in existing traditional practices. The results of the present study highlight ways in which healthcare services can implement strategies not only to improve the quality of patient outcomes, but also to offer innovative solutions for future, sustainable healthcare. The findings call for concerted efforts to increase the utilisation of allied health services to ensure the 'maximum value for spend' of the increasingly scarce health dollar. What is known about the topic? In medicine, clinician-driven strategies have been proposed to

  5. Approximate General Coulomb Model for Accretionary Prisms: An Integrated Study of the Kumano Transect, Nankai Subduction Zone, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Skarbek, Rob; Ikari, Matt; Hüpers, Andre; Rempel, Alan; Wilson, Dean; Kitajima, Hiroko

    2014-05-01

    In accretionary wedges, the mechanical and hydrologic properties along splay faults and the plate boundary fault at the base of the wedge are intimately related to properties within the wedge itself, as well as to sedimentation and/or mass wasting at the wedge surface, and accretionary flux at the wedge toe; Coulomb wedge theories tie these processes together and have been successful in their application to convergent margins. Most such theories assume for the sake of simplicity that mechanical parameters (e.g. bulk density, compressibility, frictional strength) and pore pressure are constant throughout the overlying wedge. However, the values of these parameters must necessarily change with depth and distance from the trench. Here, we derive a model for a fully general Coulomb wedge, parameterized using data specific to the Kumano transect at Nankai, to better understand the location of the basal plate interface and the properties of material composing an actively accretionary prism. We use shear strength data collected for incoming sediments at Integrated Ocean Drilling Program Site C0011 of the NanTroSEIZE project to parameterize the wedge's coefficient of friction. Preliminary results of models where the friction coefficient of the wedge decreases with depth, with other parameters constant and zero cohesion, indicate that including depth dependent frictional strength in the wedge decreases the taper angle of the wedge, with the effect becoming more pronounced with distance from the trench. This model will be further refined by including seismically and numerically determined spatial variations in fluid pressure within the wedge, as well as detailed locations of the upper and basal wedge surfaces along the Kumano transect determined from 3-D seismic data.

  6. Coulomb drag

    NASA Astrophysics Data System (ADS)

    Narozhny, B. N.; Levchenko, A.

    2016-04-01

    Coulomb drag is a transport phenomenon whereby long-range Coulomb interaction between charge carriers in two closely spaced but electrically isolated conductors induces a voltage (or, in a closed circuit, a current) in one of the conductors when an electrical current is passed through the other. The magnitude of the effect depends on the exact nature of the charge carriers and the microscopic, many-body structure of the electronic systems in the two conductors. Drag measurements have become part of the standard toolbox in condensed matter physics that can be used to study fundamental properties of diverse physical systems including semiconductor heterostructures, graphene, quantum wires, quantum dots, and optical cavities.

  7. Coulomb Breakup Problem

    SciTech Connect

    Kadyrov, A. S.; Bray, I.; Stelbovics, A. T.; Mukhamedzhanov, A. M.

    2008-12-05

    We formulate scattering theory in the framework of a surface-integral approach utilizing analytically known asymptotic forms of the three-body wave functions. This formulation is valid for both short-range and Coulombic potentials. The post and prior forms of the breakup amplitude are derived without any reference to renormalization procedures.

  8. Coulomb Damping

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2012-01-01

    Viscous damping is commonly discussed in beginning differential equations and physics texts but dry friction or Coulomb friction is not despite dry friction being encountered in many physical applications. One reason for avoiding this topic is that the equations involve a jump discontinuity in the damping term. In this article, we adopt an energy…

  9. Radon transforms and Gegenbauer-Chebyshev integrals, I

    NASA Astrophysics Data System (ADS)

    Rubin, Boris

    2016-04-01

    We suggest new modifications of the Helgason's support theorem and description of the kernel for the hyperplane Radon transform and its dual. The assumptions for functions are formulated in integral terms and close to minimal. The proofs rely on the properties of the Gegenbauer-Chebyshev integrals which generalize Abel type fractional integrals on the positive half-line.

  10. Interpreting the Coulomb-field approximation for generalized-Born electrostatics using boundary-integral equation theory.

    SciTech Connect

    Bardhan, J. P.; Mathematics and Computer Science

    2008-10-14

    The importance of molecular electrostatic interactions in aqueous solution has motivated extensive research into physical models and numerical methods for their estimation. The computational costs associated with simulations that include many explicit water molecules have driven the development of implicit-solvent models, with generalized-Born (GB) models among the most popular of these. In this paper, we analyze a boundary-integral equation interpretation for the Coulomb-field approximation (CFA), which plays a central role in most GB models. This interpretation offers new insights into the nature of the CFA, which traditionally has been assessed using only a single point charge in the solute. The boundary-integral interpretation of the CFA allows the use of multiple point charges, or even continuous charge distributions, leading naturally to methods that eliminate the interpolation inaccuracies associated with the Still equation. This approach, which we call boundary-integral-based electrostatic estimation by the CFA (BIBEE/CFA), is most accurate when the molecular charge distribution generates a smooth normal displacement field at the solute-solvent boundary, and CFA-based GB methods perform similarly. Conversely, both methods are least accurate for charge distributions that give rise to rapidly varying or highly localized normal displacement fields. Supporting this analysis are comparisons of the reaction-potential matrices calculated using GB methods and boundary-element-method (BEM) simulations. An approximation similar to BIBEE/CFA exhibits complementary behavior, with superior accuracy for charge distributions that generate rapidly varying normal fields and poorer accuracy for distributions that produce smooth fields. This approximation, BIBEE by preconditioning (BIBEE/P), essentially generates initial guesses for preconditioned Krylov-subspace iterative BEMs. Thus, iterative refinement of the BIBEE/P results recovers the BEM solution; excellent agreement

  11. Improved digital filters for evaluating Fourier and Hankel transform integrals

    USGS Publications Warehouse

    Anderson, Walter L.

    1975-01-01

    New algorithms are described for evaluating Fourier (cosine, sine) and Hankel (J0,J1) transform integrals by means of digital filters. The filters have been designed with extended lengths so that a variable convolution operation can be applied to a large class of integral transforms having the same system transfer function. A f' lagged-convolution method is also presented to significantly decrease the computation time when computing a series of like-transforms over a parameter set spaced the same as the filters. Accuracy of the new filters is comparable to Gaussian integration, provided moderate parameter ranges and well-behaved kernel functions are used. A collection of Fortran IV subprograms is included for both real and complex functions for each filter type. The algorithms have been successfully used in geophysical applications containing a wide variety of integral transforms

  12. Fast and accurate Coulomb calculation with Gaussian functions.

    PubMed

    Füsti-Molnár, László; Kong, Jing

    2005-02-15

    Coulomb interaction is one of the major time-consuming components in a density functional theory (DFT) calculation. In the last decade, dramatic progresses have been made to improve the efficiency of Coulomb calculation, including continuous fast multipole method (CFMM) and J-engine method, all developed first inside Q-Chem. The most recent development is the advent of Fourier transform Coulomb method developed by Fusti-Molnar and Pulay, and an improved version of the method has been recently implemented in Q-Chem. It replaces the least efficient part of the previous Coulomb methods with an accurate numerical integration scheme that scales in O(N2) instead of O(N4) with the basis size. The result is a much smaller slope in the linear scaling with respect to the molecular size and we will demonstrate through a series of benchmark calculations that it speeds up the calculation of Coulomb energy by several folds over the efficient existing code, i.e., the combination of CFMM and J-engine, without loss of accuracy. Furthermore, we will show that it is complementary to the latter and together the three methods offer the best performance for Coulomb part of DFT calculations, making the DFT calculations affordable for very large systems involving thousands of basis functions. PMID:15743222

  13. A Transformative Approach to Work Integrated Learning in Legal Education

    ERIC Educational Resources Information Center

    Babacan, Alperhan; Babacan, Hurriyet

    2015-01-01

    Purpose: The purpose of this paper is to discuss the current context, scope and problems in the provision of work-integrated learning (WIL) in legal education and how the adoption transformative pedagogies in WIL which is offered in legal education can foster personal and social transformation in addition to enhancing lawyering skills. The paper…

  14. Alternative representation of the linear canonical integral transform.

    PubMed

    Alieva, Tatiana; Bastiaans, Martin J

    2005-12-15

    Starting with the Iwasawa-type decomposition of a first-order optical system (or ABCD system) as a cascade of a lens, a magnifier, and an orthosymplectic system (a system that is both symplectic and orthogonal), a further decomposition of the orthosymplectic system in the form of a separable fractional Fourier transformer embedded between two spatial-coordinate rotators is proposed. The resulting decomposition of the entire first-order optical system then shows a physically attractive representation of the linear canonical integral transformation, which, in contrast to Collins integral, is valid for any ray transformation matrix. PMID:16389812

  15. The functional integral formulation of the Schrieffer–Wolff transformation

    NASA Astrophysics Data System (ADS)

    Zamani, Farzaneh; Ribeiro, Pedro; Kirchner, Stefan

    2016-06-01

    We revisit the Schrieffer–Wolff transformation and present a path integral version of this important canonical transformation. The equivalence between the low-energy sector of the Anderson model in the so-called local moment regime and the spin-isotropic Kondo model is usually established via a canonical transformation performed on the Hamiltonian, followed by a projection. Here we present a path integral formulation of the Schrieffer–Wolff transformation which relates the functional integral form of the partition function of the Anderson model to that of its effective low-energy model. The resulting functional integral assumes the form of a spin path integral and includes a geometric phase factor, i.e. a Berry phase. Our approach stresses the underlying symmetries of the model and allows for a straightforward generalization of the transformation to more involved models. It thus not only sheds new light on a classic problem, it also offers a systematic route of obtaining effective low-energy models and higher order corrections. This is demonstrated by obtaining the effective low-energy model of a quantum dot attached to two ferromagnetic leads.

  16. DNA transformations of Candida tropicalis with replicating and integrative vectors.

    PubMed

    Sanglard, D; Fiechter, A

    1992-12-01

    The alkane-assimilating yeast Candida tropicalis was used as a host for DNA transformations. A stable ade2 mutant (Ha900) obtained by UV-mutagenesis was used as a recipient for different vectors carrying selectable markers. A first vector, pMK16, that was developed for the transformation of C. albicans and carries an ADE2 gene marker and a Candida autonomously replicating sequence (CARS) element promoting autonomous replication, was compatible for transforming Ha900. Two transformant types were observed: (i) pink transformants which easily lose pMK16 under non-selective growth conditions; (ii) white transformants, in which the same plasmid exhibited a higher mitotic stability. In both cases pMK16 could be rescued from these cells in Escherichia coli. A second vector, pADE2, containing the isolated C. tropicalis ADE2, gene, was used to transform Ha900. This vector integrated in the yeast genome at homologous sites of the ade2 locus. Different integration types were observed at one or both ade2 alleles in single or in tandem repeats. PMID:1293885

  17. Asymptotic expansion of two-electron integrals and its application to Coulomb and exchange lattice sums in metallic, semimetallic, and nonmetallic crystals.

    PubMed

    Yamada, Tomonori; Brewster, Ryan P; Hirata, So

    2013-11-14

    A simple, easily implemented, accurate, and efficient approximation of long-range electron-electron-repulsion and electron-nucleus-attraction integrals is proposed. It replaces each product of two atomic-orbital (AO) basis functions of an electron by a point charge centered at the midpoint of the two AO's. The magnitude of the point charge is equal to the overlap integral of the two AO's. Each integral is then rapidly evaluated in the direct algorithm as a Coulomb interaction between two point charges. This scheme is implemented in ab initio Hartree-Fock crystalline orbital theory and tested for one-, two-, and three-dimensional solids of metallic, semimetallic, and nonmetallic electronic structures, in which the lattice sums of the direct Coulomb and/or exchange interactions are expected to be slowly convergent. It is shown that this approximation reduces operation and/or memory costs by up to an order of magnitude to achieve converged lattice sums, although the scaling (size dependence) of operation cost is unchanged. An improved criterion for truncating the exchange lattice sum is also proposed. PMID:24320254

  18. A dynamic integrated fault diagnosis method for power transformers.

    PubMed

    Gao, Wensheng; Bai, Cuifen; Liu, Tong

    2015-01-01

    In order to diagnose transformer fault efficiently and accurately, a dynamic integrated fault diagnosis method based on Bayesian network is proposed in this paper. First, an integrated fault diagnosis model is established based on the causal relationship among abnormal working conditions, failure modes, and failure symptoms of transformers, aimed at obtaining the most possible failure mode. And then considering the evidence input into the diagnosis model is gradually acquired and the fault diagnosis process in reality is multistep, a dynamic fault diagnosis mechanism is proposed based on the integrated fault diagnosis model. Different from the existing one-step diagnosis mechanism, it includes a multistep evidence-selection process, which gives the most effective diagnostic test to be performed in next step. Therefore, it can reduce unnecessary diagnostic tests and improve the accuracy and efficiency of diagnosis. Finally, the dynamic integrated fault diagnosis method is applied to actual cases, and the validity of this method is verified. PMID:25685841

  19. Study of {sup 3}He(e,e{prime}) longitudinal response functions with the integral-transform method

    SciTech Connect

    Dobretsov, V.Yu.; Efros, V.D.; Shao, B.

    1995-09-01

    The method of integral transforms is first applied to study of the {sup 3}He longitudinal response functions. The transforms are calculated from localized bound-state type solutions to an inhomogenous three-body equation. {sup 3}N dynamics and the conventional charge density operator serve as an input. The final-state interaction the contribution of the T = 3/2 final states to the problem suppressed and amounts to about 15%. This might be ascribed to symmetry properties of the final-state wave functions. The contributions of the p-wave N/N interaction and of the Coulomb interaction to the problem are studied and found to amount to several percent. Uncertainties due to different choices of s-wave NN forces are found to be of a similar magnitude. For q = 300 MeV/c, the results obtained agree with experiment. For q = 500 MeV/c, noticeable differences are detected. 20 refs., 3 figs.

  20. Factorization of the polarization transformation matrix in integrated photoelasticity.

    PubMed

    Ainola, Leo; Aben, Hillar

    2007-11-01

    In integrated photoelasticity, assessment of stresses in a three-dimensional specimen is based on the measurement of the change of polarization on many light rays that pass the specimen. Since the medium is optically anisotropic and inhomogeneous, the optical phenomena are nonlinear and solution of the inverse problem is complicated. Several methods of solving the inverse problem demand an efficient algorithm for solving the direct problem, i.e., for the calculation of the polarization transformation matrix on the basis of the stress field in the medium. We propose for this use factorization of the transformation matrix. We show that if the transformation of polarization is described by characteristic parameters, the three characteristic parameters can be determined by solving a single third-order differential equation. Since characteristic parameters can be measured experimentally, this approach can be used in practical three-dimensional stress analysis with integrated photoelasticity. PMID:17975565

  1. Integration of a piezoelectric transformer and an ultrasonic motor.

    PubMed

    Manuspiya, Suwan; Laoratanakul, Pitak; Uchino, Kenji

    2003-03-01

    Ultrasonic motors are usually operated at an AC voltage higher than a regular battery. This implies the need of a voltage step-up transformer. In this paper, we report the integration of a piezoelectric transformer (PT) with an ultrasonic motor and a simple drive circuit. The stator of the ultrasonic motor and the PT were operated in the same radial vibration mode. Their dimensions were very close to each other yielding nearly matching resonance frequencies. Consequently, they could be combined together without inductor. The drive circuit was designed by using a 555 timer as an astable multivibrator, and high-speed dual MOSFET drivers as a class D half-bridge switching amplifier. This integrated PT-ultrasonic motor performed reasonably without the use of electromagnetic transformer or inductor. PMID:12565071

  2. Path Integrals, Fourier Transforms, and Feynman's Operational Calculus

    SciTech Connect

    Ahn, Byung Moo; Johnson, G. W.

    1998-03-15

    The disentangling process is the key to Feynman's operational calculus for noncommuting operators. The main result of his heuristic calculations deals with disentangling an exponential factor. We use the Wiener and Feynman integrals to make this disentangling (or time-ordering) mathematically rigorous in the case where the analytic functions from earlier work are replaced by Fourier transforms of complex-valued measures.

  3. Transforming the Economics Curriculum by Integrating Threshold Concepts

    ERIC Educational Resources Information Center

    Karunaratne, Prashan Shayanka Mendis; Breyer, Yvonne A.; Wood, Leigh N.

    2016-01-01

    Purpose: Economics is catering to a diverse student cohort. This cohort needs to be equipped with transformative concepts that students can integrate beyond university. When a curriculum is content-driven, threshold concepts are a useful tool in guiding curriculum re-design. The paper aims to discuss these issues. Design/Methodology/Approach: The…

  4. Efficient Integration of Quantum Mechanical Wave Equations by Unitary Transforms

    SciTech Connect

    Bauke, Heiko; Keitel, Christoph H.

    2009-08-13

    The integration of time dependent quantum mechanical wave equations is a fundamental problem in computational physics and computational chemistry. The energy and momentum spectrum of a wave function imposes fundamental limits on the performance of numerical algorithms for this problem. We demonstrate how unitary transforms can help to surmount these limitations.

  5. The Effects of Integrated Transformational Leadership on Achievement

    ERIC Educational Resources Information Center

    Boberg, John Eric; Bourgeois, Steven J.

    2016-01-01

    Purpose: Greater understanding about how variables mediate the relationship between leadership and achievement is essential to the success of reform efforts that hold leaders accountable for student learning. The purpose of this paper is to test a model of integrated transformational leadership including three important school mediators.…

  6. Studies of Coulomb Gauge QCD

    SciTech Connect

    Adam P. Szczepaniak; Eric S. Swanson

    2000-12-12

    Here we will discuss how the nonabelian Coulomb kernel exhibits confinement already at the mean field level. In the heavy quark limit residual interactions between heavy quarks and transverse gluons are spin dependent i.e., relativistic and can be calculated using the Foldy-Wouthuysen transformation. This makes the Coulomb gauge suitable for studying the nonrelativistic limit. Finally it is possible to use standard mean field techniques to define quasiparticle excitations, which, as we discuss below, have similar properties to what is usually assumed about constituent quarks in the light quark sector.

  7. Implementing quantum Fourier transform with integrated photonic devices

    NASA Astrophysics Data System (ADS)

    Tabia, Gelo Noel

    2014-03-01

    Many quantum algorithms that exhibit exponential speedup over their classical counterparts employ the quantum Fourier transform, which is used to solve interesting problems such as prime factorization. Meanwhile, nonclassical interference of single photons achieved on integrated platforms holds the promise of achieving large-scale quantum computation with multiport devices. An optical multiport device can be built to realize any quantum circuit as a sequence of unitary operations performed by beam splitters and phase shifters on path-encoded qudits. In this talk, I will present a recursive scheme for implementing quantum Fourier transform with a multimode interference photonic integrated circuit. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation.

  8. Mechanism of integrating foreign DNA during transformation of Bacillus subtilis.

    PubMed Central

    Duncan, C H; Wilson, G A; Young, F E

    1978-01-01

    Genes encoding thymidylate synthetase from Bacillus subtilis bacteriophages were cloned in Escherichia coli. Chimeric plasmids pCD1 and pCD3 were constructed from site-specific endonuclease digests of bacteriophage phi3T DNA cloned in pMB9 in E. coli. Similar cloning techniques with bacteriophage beta22 DNA yielded chimeric plasmids pCD4, pCD5, and pCD6. Endonuclease digests of DNA from pCD1 and pCD3 propagated in E. coli or from DNA isolated from bacteriophage phi3T propagated in B. subtilis transformed B. subtilis from Thy- to Thy+. Intact DNA from bacteriophage beta22, endonuclease digests of beta22 DNA, and a chimeric plasmid (pCD5) composed only of the thybeta22 gene and pMB9 did not transform B. subtilis from Thy- to Thy+ even though pCD5 could transform Thy- E. coli to Thy+. However, if the thybeta22 fragment from pCD5 was introduced into another chimeric plasmid, pCD2, that contains a region of homology to the chromosome of B. subtilis in addition to pMB9, transformation of Thy- clones of B. subtilis was possible. Furthermore, Southern hybridization analyses of the digests of chromosomal DNA from the Thy+ transformants established that the entire chimeric plasmid was incorporated into the chromosome of B. subtilis. Treatment of these plasmids with site-specific endonucleases abolished transformation. These results indicated that the entire chimeric plasmid can be incorporated into the chromosome of B. subtilis by a Campbell-like model. Therefore, an additional mechanism for transformation exists whereby plasmids can be integrated if sufficient chromosomal homology is maintained. Images PMID:99740

  9. Renormalization in Coulomb gauge QCD

    NASA Astrophysics Data System (ADS)

    Andraši, A.; Taylor, John C.

    2011-04-01

    In the Coulomb gauge of QCD, the Hamiltonian contains a non-linear Christ-Lee term, which may alternatively be derived from a careful treatment of ambiguous Feynman integrals at 2-loop order. We investigate how and if UV divergences from higher order graphs can be consistently absorbed by renormalization of the Christ-Lee term. We find that they cannot.

  10. Integrated polyoma genomes in inducible permissive transformed cells.

    PubMed Central

    Chartrand, P; Gusew-Chartrand, N; Bourgaux, P

    1981-01-01

    Using the approach described by Botchan, Topp, and Sambrook (Cell 9:269-287, 1976), we analyzed the organization of the integrated viral sequences in five clonal isolates from the same permissive, inducible cell line (Cyp line) transformed by the tsP155 mutant of polyoma virus. In all five clones, viral sequences were found that could be assigned to a common integration site, as they were joined to the cellular DNA in the same fashion in every instance. However, the sequences comprised between these points differed markedly from clone to clone, as if cell propagation had been accompanied by amplification or recombination or both within the viral insertion. When the clones were compared, no correlation could be found between the abundance, or the organization, of the integrated viral sequences and the amount, or the nature, of the free viral DNA molecules produced during induction. Altogether, our findings suggest that specific events, occurring during either the excision or the subsequent replication of the integrated viral sequences, are responsible for the predominant production of nondefective viral DNA molecules by permissive transformed cells, such as Cyp cells. Images PMID:6268808

  11. Numerical approach to Coulomb gauge QCD

    SciTech Connect

    Matevosyan, Hrayr H.; Szczepaniak, Adam P.; Bowman, Patrick O.

    2008-07-01

    We calculate the ghost two-point function in Coulomb gauge QCD with a simple model vacuum gluon wave function using Monte Carlo integration. This approach extends the previous analytic studies of the ghost propagator with this ansatz, where a ladder-rainbow expansion was unavoidable for calculating the path integral over gluon field configurations. The new approach allows us to study the possible critical behavior of the coupling constant, as well as the Coulomb potential derived from the ghost dressing function. We demonstrate that IR enhancement of the ghost correlator or Coulomb form factor fails to quantitatively reproduce confinement using Gaussian vacuum wave functional.

  12. Experimental Evaluation of Integral Transformations for Engineering Drawings Vectorization

    NASA Astrophysics Data System (ADS)

    Vaský, Jozef; Gramblička, Matúš

    2014-12-01

    The concept of digital manufacturing supposes application of digital technologies in the whole product life cycle. Direct digital manufacturing includes such information technology processes, where products are directly manufactured from 3D CAD model. In digital manufacturing, engineering drawing is replaced by CAD product model. In the contemporary practice, lots of engineering paper-based drawings are still archived. They could be digitalized by scanner and stored to one of the raster graphics format and after that vectorized for interactive editing in the specific software system for technical drawing or for archiving in some of the standard vector graphics file format. The vector format is suitable for 3D model generating, too.The article deals with using of selected integral transformations (Fourier, Hough) in the phase of digitalized raster engineering drawings vectorization.

  13. On the modelling of Coulomb friction

    NASA Astrophysics Data System (ADS)

    Cull, S. J.; Tucker, R. W.

    1999-03-01

    This paper analyses two different representations of Coulomb friction in the context of a dynamic simulation of the torsional vibrations of a driven drill-string. A simple model is used to compare the relative merits of a piecewise analytic approach using a discontinuous friction profile to a numerical integration using a smooth nonlinear representation of the Coulomb friction. In both cases the effects of viscous damping on the excitation of torsional relaxation oscillations are exhibited.

  14. Investigating Coulomb's Law.

    ERIC Educational Resources Information Center

    Noll, Ellis; Koehlinger, Mervin; Kowalski, Ludwik; Swackhamer, Gregg

    1998-01-01

    Describes the use of a computer-linked camera to demonstrate Coulomb's law. Suggests a way of reducing the difficulties in presenting Coulomb's law by teaching the inverse square law of gravity and the inverse square law of electricity in the same unit. (AIM)

  15. Diffusion in Coulomb crystals.

    PubMed

    Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K

    2011-07-01

    Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions "hop" in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter Γ=175 to Coulomb parameters up to Γ=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous. PMID:21867316

  16. FAST TRACK COMMUNICATION: An infinite family of superintegrable deformations of the Coulomb potential

    NASA Astrophysics Data System (ADS)

    Post, Sarah; Winternitz, Pavel

    2010-06-01

    We introduce a new family of Hamiltonians with a deformed Kepler-Coulomb potential dependent on an indexing parameter k. We show that this family is superintegrable for all rational k and compute the classical trajectories and quantum wavefunctions. We show that this system is related, via coupling constant metamorphosis, to a family of superintegrable deformations of the harmonic oscillator given by Tremblay, Turbiner and Winternitz. In doing so, we prove that all Hamiltonians with an oscillator term are related by coupling constant metamorphosis to systems with a Kepler-Coulomb term, both on Euclidean space. We also look at the effect of the transformation on the integrals of the motion, the classical trajectories and the wavefunctions, and give the transformed integrals explicitly for the classical system.

  17. Spherical Calogero model with oscillator/Coulomb potential: Classical case

    NASA Astrophysics Data System (ADS)

    Correa, Francisco; Hakobyan, Tigran; Lechtenfeld, Olaf; Nersessian, Armen

    2016-06-01

    We construct the Hamiltonians and symmetry generators of Calogero-oscillator and Calogero-Coulomb models on the N -dimensional sphere within the matrix-model reduction approach. Our method also produces the integrable Calogero-Coulomb-Stark model on the sphere and proves the integrability of the spin extensions of all these systems.

  18. Self-energy operator for an electron in an external Coulomb potential

    SciTech Connect

    Hostler, L.C.

    1987-03-01

    The self-energy operator for an electron in an external Coulomb potential is investigated analytically using a mass eigenfunction expansion concept reported earlier. Contour integration techniques in the complex m/sup 2/ plane are used to combine bound state and continuum contributions into a single integral. The result is a relatively simple integral representation for the mass operator. Only terms ignoring the ''shift correction'' are considered in this preliminary study. A transformation to a basis of relativistic Coulomb Sturmian functions exhibits the Z..cap alpha.. dependence of the integrand in a strikingly simple way. The entire investigation is set in the framework of the ''scalar formalism'' for quantum electrodynamics investigated earlier by a number of authors and based on the ''second-order'' Dirac equation, )Pix(1+isigma)xPi+m/sup 2/)Phi = 0, where Phi is a 2 x 1 Pauli spinor.

  19. New approach to folding with the Coulomb wave function

    SciTech Connect

    Blokhintsev, L. D.; Savin, D. A.; Kadyrov, A. S.; Mukhamedzhanov, A. M.

    2015-05-15

    Due to the long-range character of the Coulomb interaction theoretical description of low-energy nuclear reactions with charged particles still remains a formidable task. One way of dealing with the problem in an integral-equation approach is to employ a screened Coulomb potential. A general approach without screening requires folding of kernels of the integral equations with the Coulomb wave. A new method of folding a function with the Coulomb partial waves is presented. The partial-wave Coulomb function both in the configuration and momentum representations is written in the form of separable series. Each term of the series is represented as a product of a factor depending only on the Coulomb parameter and a function depending on the spatial variable in the configuration space and the momentum variable if the momentum representation is used. Using a trial function, the method is demonstrated to be efficient and reliable.

  20. The Impact of Technology Integration through a Transformative Approach

    ERIC Educational Resources Information Center

    Cubillos, Jo Ann

    2013-01-01

    The integration of technology into classroom instruction in K-12 schools remains problematic. The problems associated with this integration are troubling, as technology integration may change a teacher's pedagogy toward more innovative approaches that increase student achievement. The purpose of this study was to document teachers' experiences as…

  1. Eigenfunctions and eigenoperators of cyclic integral transforms with application to Gaussian beam propagation

    NASA Astrophysics Data System (ADS)

    McCallum, Matthew S.

    An integral transform which reproduces a transformable input function after a finite number N of successive applications is known as a cyclic transform. Of course, such a transform will reproduce an arbitrary transformable input after N applications, but it also admits eigenfunction inputs which will be reproduced after a single application of the transform. These transforms and their eigenfunctions appear in various applications, and the systematic determination of eigenfunctions of cyclic integral transforms has been a problem of interest to mathematicians since at least the early twentieth century. In this work we review the various approaches to this problem, providing generalizations of published expressions from previous approaches. We then develop a new formalism, differential eigenoperators, that reduces the eigenfunction problem for a cyclic transform to an eigenfunction problem for a corresponding ordinary differential equation. In this way we are able to relate eigenfunctions of integral equations to boundary-value problems, which are typically easier to analyze. We give extensive examples and discussion via the specific case of the Fourier transform. We also relate this approach to two formalisms that have been of interest to the mathematical physics community---hyperdifferential operators and linear canonical transforms. We show how this new approach reproduces known results of Fourier optics regarding free-space diffractive propagation of Gaussian beams in both one and two dimensions. Finally we discuss the group-theoretical aspects of the formalism and describe an isomorphism between roots of the identity transform and complex roots of unity. In the appendix we derive several technical results related to integrability and transformability of solutions in the Fourier transform case, and we prove two theorems---one of them new---on polynomial roots. We conclude that the formalism offers a new and equally valuable perspective on an interesting

  2. Bäcklund transformations for Darboux integrable differential systems: Examples and applications

    NASA Astrophysics Data System (ADS)

    Anderson, Ian M.; Fels, Mark E.

    2016-04-01

    In this article we demonstrate a new symmetry based method for constructing Bäcklund transformations by finding explicit Bäcklund transformations between Darboux integrable systems. This results in a number of new examples of Bäcklund transformations which are quite different in character than those typically found in the literature. The relation between the intermediate integrals for Darboux integrable systems and the differential invariants of the Vessiot group is also illustrated. We then show that a well known class of Bäcklund transformations between a Darboux integrable Monge-Ampère system and the wave equation always arises by this method. The results of this paper build upon the presentation of Darboux integrable systems as quotients of differential systems by symmetry groups.

  3. Giant Coulomb blockade magnetoresistance

    SciTech Connect

    Zhang, Xiaoguang; Wen, Z. C.; Wei, H. X.; Han, Prof. X. F.

    2010-01-01

    We show that the Coulomb blockade voltage can be made to depend strongly on the electron spin in a thin magnetic granular layer inserted in the middle of an insulating layer of a tunnel junction. This strong spin dependence is predicted from the spin-dependent inter-granular conductance through any of the following effects within the granular layer, giant magnetoresistance (GMR), tunneling magnetoresistance (TMR), colossal magnetoresistance (CMR), or GMR through a polymer spacer. The resulting Coulomb blockade magnetoresistance (CBMR) ratio can exceed the magnetoresistance ratio of the granular layer itself by orders of magnitude. Unlike other magenetoresistance effects, the CBMR effect does not require magnetic electrodes.

  4. Confinement of Coulomb balls

    SciTech Connect

    Arp, O.; Block, D.; Klindworth, M.; Piel, A.

    2005-12-15

    A model for the confinement of the recently discovered Coulomb balls is proposed. These spherical three-dimensional plasma crystals are trapped inside a rf discharge under gravity conditions and show an unusual structural order in complex plasmas. Measurements of the thermophoretic force acting on the trapped dust particles and simulations of the plasma properties of the discharge are presented. The proposed model of confinement considers thermophoretic, ion-drag, and electric field forces, and shows excellent agreement with the observations. The findings suggest that self-confinement does not significantly contribute to the structural properties of Coulomb balls.

  5. 76 FR 17145 - Agency Information Collection Activities: Business Transformation-Automated Integrated Operating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Business Transformation--Automated Integrated Operating Environment (IOE), New Information Collection; Comment Request... Operating Environment (IOE); OMB Control No. 1615-NEW. SUMMARY: USCIS is developing an automated...

  6. 76 FR 63941 - Agency Information Collection Activities: Business Transformation-Automated Integrated Operating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-14

    ... SECURITY Citizenship and Immigration Services Agency Information Collection Activities: Business Transformation--Automated Integrated Operating Environment (IOE), New Information Collection; Comment Request..., 2011, USCIS published a 60-day notice in the Federal Register at 76 FR 1745, seeking comment on...

  7. Implementation of an Integrated, Portable Transformer Condition Monitoring Instrument in the Classroom and On-Site

    ERIC Educational Resources Information Center

    Chatterjee, B.; Dey, D.; Chakravorti, S.

    2010-01-01

    The development of integrated, portable, transformer condition monitoring (TCM) equipment for classroom demonstrations as well as for student exercises conducted in the field is discussed. Demonstrations include experimentation with real-world transformers to illustrate concepts such as polarization and depolarization current through oil-paper…

  8. Lessons from the Desert: Integrating Managerial Expertise and Learning for Organizational Transformation

    ERIC Educational Resources Information Center

    Roth, George

    2004-01-01

    Reflection upon a field study of a corporate transformation provides insights into the application and integration of organizational learning theory and frameworks with local, corporate knowledge. In the corporate transformation studied this local knowledge came from consumer psychology, marketing campaigns and the use of media. When these ideas…

  9. Integration of planar transformer and/or planar inductor with power switches in power converter

    DOEpatents

    Chen, Kanghua; Ahmed, Sayeed; Zhu, Lizhi

    2007-10-30

    A power converter integrates at least one planar transformer comprising a multi-layer transformer substrate and/or at least one planar inductor comprising a multi-layer inductor substrate with a number of power semiconductor switches physically and thermally coupled to a heat sink via one or more multi-layer switch substrates.

  10. Coulomb problem for vector bosons

    SciTech Connect

    Kuchiev, M.Yu.; Flambaum, V.V.

    2006-05-01

    The Coulomb problem for vector bosons W{sup {+-}} incorporates a well-known difficulty; the charge of the boson localized in a close vicinity of the attractive Coulomb center proves to be infinite. The paradox is shown to be resolved by the QED vacuum polarization, which brings in a strong effective repulsion that eradicates the infinite charge of the boson on the Coulomb center. This property allows one to define the Coulomb problem for vector bosons properly.

  11. Feynman rules for Coulomb gauge QCD

    SciTech Connect

    Andrasi, A.; Taylor, J.C.

    2012-10-15

    The Coulomb gauge in nonabelian gauge theories is attractive in principle, but beset with technical difficulties in perturbation theory. In addition to ordinary Feynman integrals, there are, at 2-loop order, Christ-Lee (CL) terms, derived either by correctly ordering the operators in the Hamiltonian, or by resolving ambiguous Feynman integrals. Renormalization theory depends on the sub-graph structure of ordinary Feynman graphs. The CL terms do not have a sub-graph structure. We show how to carry out renormalization in the presence of CL terms, by re-expressing these as 'pseudo-Feynman' integrals. We also explain how energy divergences cancel. - Highlights: Black-Right-Pointing-Pointer In Coulomb gauge QCD, we re-express Christ-Lee terms in the Hamiltonian as pseudo-Feynman integrals. Black-Right-Pointing-Pointer This gives a subgraph structure, and allows the ordinary renormalization process. Black-Right-Pointing-Pointer It also leads to cancellation of energy-divergences.

  12. Integrated optics in an electrically scanned imaging Fourier transform spectrometer

    NASA Technical Reports Server (NTRS)

    Breckinridge, James B. (Inventor); Ocallaghan, Fred G. (Inventor)

    1982-01-01

    An efficient, lightweight and stable, Fourier transform spectrometer was developed. The mechanical slide mechanism needed to create a path difference was eliminated by the use of retro-reflecting mirrors in a monolithic interferometer assembly in which the mirrors are not at 90 degrees to the propagation vector of the radiation, but rather at a small angle. The resulting plane wave fronts create a double-sided inteferogram of the source irradiance distribution which is detected by a charge-coupled device image sensor array. The position of each CCD pixel in the array is an indication of the path difference between the two retro-reflecting mirrors in the monolithic optical structure. The Fourier transform of the signals generated by the image sensor provide the spectral irradiance distribution of the source. For imaging, the interferometer assembly scans the source of irradiation by moving the entire instrument, such as would occur if it was fixedly mounted to a moving platform, i.e., a spacecraft. During scanning, the entrace slot to the monolithic optical structure sends different pixels to corresponding interferograms detected by adjacent columns of pixels of the image sensor.

  13. Transforming Water Management: an Emerging Promise of Integrated Earth Observations

    NASA Astrophysics Data System (ADS)

    Lawford, R. G.

    2011-12-01

    Throughout its history, civilization has relied on technology to facilitate many of its advances. New innovations and technologies have often provided strategic advantages that have led to transformations in institutions, economies and ultimately societies. Observational and information technologies are leading to significant developments in the water sector. After a brief introduction tracing the role of observational technologies in the areas of hydrology and water cycle science, this talk explores the existing and potential contributions of remote sensing data in water resource management around the world. In particular, it outlines the steps being undertaken by the Group on Earth Observations (GEO) and its Water Task to facilitate capacity building efforts in water management using Earth Observations in Asia, Africa and Latin and Caribbean America. Success stories on the benefits of using Earth Observations and applying GEO principles are provided. While GEO and its capacity building efforts are contributing to the transformation of water management through interoperability, data sharing, and capacity building, the full potential of these contributions has not been fully realized because impediments and challenges still remain.

  14. Integrating the Scholarship on Women: Transforming the Curriculum.

    ERIC Educational Resources Information Center

    Coulter, Sara; Hedges, Elaine

    Townson State University's 3-year project integrated new scholarship on women into the curriculum, with emphasis on introductory survey courses in eight disciplines: art, biology, business, education, English, history, psychology, and sociology. About 70 faculty met in workshops for five semesters to (1) read and discuss new scholarship on women;…

  15. Integrative Approach for a Transformative Freshman-Level STEM Curriculum

    PubMed Central

    Curran, Kathleen L.; Olsen, Paul E.; Nwogbaga, Agashi P.; Stotts, Stephanie

    2016-01-01

    In 2014 Wesley College adopted a unified undergraduate program of evidence-based high-impact teaching practices. Through foundation and federal and state grant support, the college completely revised its academic core curriculum and strengthened its academic support structures by including a comprehensive early alert system for at-risk students. In this core, science, technology, engineering, and mathematics (STEM) faculty developed fresh manifestations of integrated concept-based introductory courses and revised upper-division STEM courses around student-centered learning. STEM majors can participate in specifically designed paid undergraduate research experiences in directed research elective courses. Such a college-wide multi-tiered approach results in institutional cultural change. PMID:27064213

  16. Darboux Transformation for the Vector Sine-Gordon Equation and Integrable Equations on a Sphere

    NASA Astrophysics Data System (ADS)

    Mikhailov, Alexander V.; Papamikos, Georgios; Wang, Jing Ping

    2016-07-01

    We propose a method for construction of Darboux transformations, which is a new development of the dressing method for Lax operators invariant under a reduction group. We apply the method to the vector sine-Gordon equation and derive its Bäcklund transformations. We show that there is a new Lax operator canonically associated with our Darboux transformation resulting an evolutionary differential-difference system on a sphere. The latter is a generalised symmetry for the chain of Bäcklund transformations. Using the re-factorisation approach and the Bianchi permutability of the Darboux transformations, we derive new vector Yang-Baxter map and integrable discrete vector sine-Gordon equation on a sphere.

  17. Semiclassical Coulomb field

    SciTech Connect

    Polonyi, J.

    2008-06-15

    The contribution of different modes of the Coulomb field to decoherence and to the dynamical breakdown of the time reversal invariance is calculated in the one-loop approximation for nonrelativistic electron gas. The dominant contribution was found to come from the usual collective modes in the plasma, namely, the zero-sound and the plasmon oscillations. The length scale of the quantum-classical transition is found to be close to the Thomas-Fermi screening length. It is argued that the extension of these modes to the whole Fock space yields optimal pointer states.

  18. Ion Coulomb crystals

    NASA Astrophysics Data System (ADS)

    Drewsen, Michael

    2015-03-01

    The following text will give a brief introduction to the physics of the spatially ordered structures, so-called Coulomb crystals, that appear when confined ions are cooled to sufficiently low temperatures. It will as well briefly comment on the very diverse scientific applications of such crystals, which have emerged the past two decades. While this document lacks figures, it includes a substantial number of references in which more detailed information can be found. It is the hope that the text will stimulate the reader to dig deeper into one or more of the discussed subjects and inspire her/him to think about new potential applications.

  19. Feynman rules for Coulomb gauge QCD

    NASA Astrophysics Data System (ADS)

    Andraši, A.; Taylor, J. C.

    2012-10-01

    The Coulomb gauge in nonabelian gauge theories is attractive in principle, but beset with technical difficulties in perturbation theory. In addition to ordinary Feynman integrals, there are, at 2-loop order, Christ-Lee (CL) terms, derived either by correctly ordering the operators in the Hamiltonian, or by resolving ambiguous Feynman integrals. Renormalization theory depends on the sub-graph structure of ordinary Feynman graphs. The CL terms do not have a sub-graph structure. We show how to carry out renormalization in the presence of CL terms, by re-expressing these as 'pseudo-Feynman' integrals. We also explain how energy divergences cancel.

  20. TRANSFORMATION

    SciTech Connect

    LACKS,S.A.

    2003-10-09

    Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).

  1. Helicity is the only integral invariant of volume-preserving transformations.

    PubMed

    Enciso, Alberto; Peralta-Salas, Daniel; de Lizaur, Francisco Torres

    2016-02-23

    We prove that any regular integral invariant of volume-preserving transformations is equivalent to the helicity. Specifically, given a functional I defined on exact divergence-free vector fields of class C(1) on a compact 3-manifold that is associated with a well-behaved integral kernel, we prove that I is invariant under arbitrary volume-preserving diffeomorphisms if and only if it is a function of the helicity. PMID:26864201

  2. Helicity is the only integral invariant of volume-preserving transformations

    PubMed Central

    Enciso, Alberto; Peralta-Salas, Daniel; de Lizaur, Francisco Torres

    2016-01-01

    We prove that any regular integral invariant of volume-preserving transformations is equivalent to the helicity. Specifically, given a functional ℐ defined on exact divergence-free vector fields of class C1 on a compact 3-manifold that is associated with a well-behaved integral kernel, we prove that ℐ is invariant under arbitrary volume-preserving diffeomorphisms if and only if it is a function of the helicity. PMID:26864201

  3. Chemical Transformation System: Cloud Based Cheminformatic Services to Support Integrated Environmental Modeling

    EPA Science Inventory

    Integrated Environmental Modeling (IEM) systems that account for the fate/transport of organics frequently require physicochemical properties as well as transformation products. A myriad of chemical property databases exist but these can be difficult to access and often do not co...

  4. A system for multi-locus chromosomal integration and transformation-free selection marker rescue

    PubMed Central

    Siddiqui, Michael S.; Choksi, Atri; Smolke, Christina D.

    2014-01-01

    Yeast integrating plasmids (YIPs) are a versatile tool for stable integration in Saccharomyces cerevisiae. However, current YIP systems necessitate time- and labor-intensive methods for cloning and selection marker rescue. Here we describe the design, construction, and validation of a new YIP system capable of accelerating the stable integration of multiple expression constructs into different loci in the yeast S. cerevisiae. These “directed pop-out” plasmids enable a simple, two-step integration protocol that results in a scarless integration alongside a complete rescue of the selection marker. These plasmids combine three key features: a dedicated “YIPout” fragment directs a recombination event that rescues the selection marker while avoiding undesired excision of the target DNA sequence, a multi-fragment modular DNA assembly system simplifies cloning, and a new set of counterselectable markers enables serial integration followed by a transformation-free marker rescue event. We constructed and tested directed pop-out YIPs for integration of fluorescent reporter genes into four yeast loci. We validated our new YIP design by integrating three reporter genes into three different loci with transformation-free rescue of selection markers. These new YIP designs will facilitate the construction of yeast strains that express complex heterologous metabolic pathways. PMID:25226817

  5. TRANSFORMER

    DOEpatents

    Baker, W.R.

    1959-08-25

    Transformers of a type adapted for use with extreme high power vacuum tubes where current requirements may be of the order of 2,000 to 200,000 amperes are described. The transformer casing has the form of a re-entrant section being extended through an opening in one end of the cylinder to form a coaxial terminal arrangement. A toroidal multi-turn primary winding is disposed within the casing in coaxial relationship therein. In a second embodiment, means are provided for forming the casing as a multi-turn secondary. The transformer is characterized by minimized resistance heating, minimized external magnetic flux, and an economical construction.

  6. Innovative use of the integrative review to evaluate evidence of technology transformation in healthcare.

    PubMed

    Phillips, Andrew B; Merrill, Jacqueline A

    2015-12-01

    Healthcare is in a period significant transformational activity through the accelerated adoption of healthcare technologies, new reimbursement systems that emphasize shared savings and care coordination, and the common place use of mobile technologies by patients, providers, and others. The complexity of healthcare creates barriers to transformational activity and has the potential to inhibit the desired paths toward change envisioned by policymakers. Methods for understanding how change is occurring within this complex environment are important to the evaluation of delivery system reform and the role of technology in healthcare transformation. This study examines the use on an integrative review methodology to evaluate the healthcare literature for evidence of technology transformation in healthcare. The methodology integrates the evaluation of a broad set of literature with an established evaluative framework to develop a more complete understanding of a particular topic. We applied this methodology and the framework of punctuated equilibrium (PEq) to the analysis of the healthcare literature from 2004 to 2012 for evidence of technology transformation, a time during which technology was at the forefront of healthcare policy. The analysis demonstrated that the established PEq framework applied to the literature showed considerable potential for evaluating the progress of policies that encourage healthcare transformation. Significant inhibitors to change were identified through the integrative review and categorized into ten themes that describe the resistant structure of healthcare delivery: variations in the environment; market complexity; regulations; flawed risks and rewards; change theories; barriers; ethical considerations; competition and sustainability; environmental elements, and internal elements. We hypothesize that the resistant nature of the healthcare system described by this study creates barriers to the direct consumer involvement and engagement

  7. Classification of the quantum two-dimensional superintegrable systems with quadratic integrals and the Staeckel transforms

    SciTech Connect

    Daskaloyannis, C. Tanoudis, Y.

    2008-05-15

    The two-dimensional quantum superintegrable systems with quadratic integrals of motion on a manifold are classified by using the quadratic associative algebra of the integrals of motion. There are six general fundamental classes of quantum superintegrable systems corresponding to the classical ones. Analytic formulas for the involved integrals are calculated in all the cases. All the known quantum superintegrable systems with quadratic integrals are classified as special cases of these six general classes. The coefficients of the quadratic associative algebra of integrals are calculated and they are compared to the coefficients of the corresponding coefficients of the Poisson quadratic algebra of the classical systems. The quantum coefficients are similar to the classical ones multiplied by a quantum coefficient -{h_bar}{sup 2} plus a quantum deformation of order {h_bar}{sup 4} and {h_bar}{sup 6}. The systems inside the classes are transformed using Staeckel transforms in the quantum case as in the classical case. The general form of the Staeckel transform between superintegrable systems is discussed.

  8. Integrative gene transfer in the truffle Tuber borchii by Agrobacterium tumefaciens-mediated transformation.

    PubMed

    Brenna, Andrea; Montanini, Barbara; Muggiano, Eleonora; Proietto, Marco; Filetici, Patrizia; Ottonello, Simone; Ballario, Paola

    2014-01-01

    Agrobacterium tumefaciens-mediated transformation is a powerful tool for reverse genetics and functional genomic analysis in a wide variety of plants and fungi. Tuber spp. are ecologically important and gastronomically prized fungi ("truffles") with a cryptic life cycle, a subterranean habitat and a symbiotic, but also facultative saprophytic lifestyle. The genome of a representative member of this group of fungi has recently been sequenced. However, because of their poor genetic tractability, including transformation, truffles have so far eluded in-depth functional genomic investigations. Here we report that A. tumefaciens can infect Tuber borchii mycelia, thereby conveying its transfer DNA with the production of stably integrated transformants. We constructed two new binary plasmids (pABr1 and pABr3) and tested them as improved transformation vectors using the green fluorescent protein as reporter gene and hygromycin phosphotransferase as selection marker. Transformants were stable for at least 12 months of in vitro culture propagation and, as revealed by TAIL- PCR analysis, integration sites appear to be heterogeneous, with a preference for repeat element-containing genome sites. PMID:24949275

  9. Non-parametric transformation for data correlation and integration: From theory to practice

    SciTech Connect

    Datta-Gupta, A.; Xue, Guoping; Lee, Sang Heon

    1997-08-01

    The purpose of this paper is two-fold. First, we introduce the use of non-parametric transformations for correlating petrophysical data during reservoir characterization. Such transformations are completely data driven and do not require a priori functional relationship between response and predictor variables which is the case with traditional multiple regression. The transformations are very general, computationally efficient and can easily handle mixed data types for example, continuous variables such as porosity, permeability and categorical variables such as rock type, lithofacies. The power of the non-parametric transformation techniques for data correlation has been illustrated through synthetic and field examples. Second, we utilize these transformations to propose a two-stage approach for data integration during heterogeneity characterization. The principal advantages of our approach over traditional cokriging or cosimulation methods are: (1) it does not require a linear relationship between primary and secondary data, (2) it exploits the secondary information to its fullest potential by maximizing the correlation between the primary and secondary data, (3) it can be easily applied to cases where several types of secondary or soft data are involved, and (4) it significantly reduces variance function calculations and thus, greatly facilitates non-Gaussian cosimulation. We demonstrate the data integration procedure using synthetic and field examples. The field example involves estimation of pore-footage distribution using well data and multiple seismic attributes.

  10. Integrative gene transfer in the truffle Tuber borchii by Agrobacterium tumefaciens-mediated transformation

    PubMed Central

    2014-01-01

    Agrobacterium tumefaciens-mediated transformation is a powerful tool for reverse genetics and functional genomic analysis in a wide variety of plants and fungi. Tuber spp. are ecologically important and gastronomically prized fungi (“truffles”) with a cryptic life cycle, a subterranean habitat and a symbiotic, but also facultative saprophytic lifestyle. The genome of a representative member of this group of fungi has recently been sequenced. However, because of their poor genetic tractability, including transformation, truffles have so far eluded in-depth functional genomic investigations. Here we report that A. tumefaciens can infect Tuber borchii mycelia, thereby conveying its transfer DNA with the production of stably integrated transformants. We constructed two new binary plasmids (pABr1 and pABr3) and tested them as improved transformation vectors using the green fluorescent protein as reporter gene and hygromycin phosphotransferase as selection marker. Transformants were stable for at least 12 months of in vitro culture propagation and, as revealed by TAIL- PCR analysis, integration sites appear to be heterogeneous, with a preference for repeat element-containing genome sites. PMID:24949275

  11. Variable transformations and Gauss-Legendre quadrature for integrals with endpoint singularities

    NASA Astrophysics Data System (ADS)

    Sidi, Avram

    2009-09-01

    Gauss-Legendre quadrature formulas have excellent convergence properties when applied to integrals int^1_0f(x) dx with fin C^infty[0,1] . However, their performance deteriorates when the integrands f(x) are in C^infty(0,1) but are singular at x=0 and/or x=1 . One way of improving the performance of Gauss-Legendre quadrature in such cases is by combining it with a suitable variable transformation such that the transformed integrand has weaker singularities than those of f(x) . Thus, if x=psi(t) is a variable transformation that maps [0,1] onto itself, we apply Gauss-Legendre quadrature to the transformed integral int^1_{0}f(psi(t))psi'(t) dt , whose singularities at t=0 and/or t=1 are weaker than those of f(x) at x=0 and/or x=1 . In this work, we first define a new class of variable transformations we denote widetilde{mathcal{S}}_{p,q} , where p and q are two positive parameters that characterize it. We also give a simple and easily computable representative of this class. Next, by invoking some recent results by the author concerning asymptotic expansions of Gauss-Legendre quadrature approximations as the number of abscissas tends to infinity, we present a thorough study of convergence of the combined approximation procedure, with variable transformations from widetilde{mathcal{S}}_{p,q} . We show how optimal results can be obtained by adjusting the parameters p and q of the variable transformation in an appropriate fashion. We also give numerical examples that confirm the theoretical results.

  12. Ontology for Transforming Geo-Spatial Data for Discovery and Integration of Scientific Data

    NASA Astrophysics Data System (ADS)

    Nguyen, L.; Chee, T.; Minnis, P.

    2013-12-01

    Discovery and access to geo-spatial scientific data across heterogeneous repositories and multi-discipline datasets can present challenges for scientist. We propose to build a workflow for transforming geo-spatial datasets into semantic environment by using relationships to describe the resource using OWL Web Ontology, RDF, and a proposed geo-spatial vocabulary. We will present methods for transforming traditional scientific dataset, use of a semantic repository, and querying using SPARQL to integrate and access datasets. This unique repository will enable discovery of scientific data by geospatial bound or other criteria.

  13. Integrated Personal Health Records: Transformative Tools for Consumer-Centric Care

    PubMed Central

    Detmer, Don; Bloomrosen, Meryl; Raymond, Brian; Tang, Paul

    2008-01-01

    Background Integrated personal health records (PHRs) offer significant potential to stimulate transformational changes in health care delivery and self-care by patients. In 2006, an invitational roundtable sponsored by Kaiser Permanente Institute, the American Medical Informatics Association, and the Agency for Healthcare Research and Quality was held to identify the transformative potential of PHRs, as well as barriers to realizing this potential and a framework for action to move them closer to the health care mainstream. This paper highlights and builds on the insights shared during the roundtable. Discussion While there is a spectrum of dominant PHR models, (standalone, tethered, integrated), the authors state that only the integrated model has true transformative potential to strengthen consumers' ability to manage their own health care. Integrated PHRs improve the quality, completeness, depth, and accessibility of health information provided by patients; enable facile communication between patients and providers; provide access to health knowledge for patients; ensure portability of medical records and other personal health information; and incorporate auto-population of content. Numerous factors impede widespread adoption of integrated PHRs: obstacles in the health care system/culture; issues of consumer confidence and trust; lack of technical standards for interoperability; lack of HIT infrastructure; the digital divide; uncertain value realization/ROI; and uncertain market demand. Recent efforts have led to progress on standards for integrated PHRs, and government agencies and private companies are offering different models to consumers, but substantial obstacles remain to be addressed. Immediate steps to advance integrated PHRs should include sharing existing knowledge and expanding knowledge about them, building on existing efforts, and continuing dialogue among public and private sector stakeholders. Summary Integrated PHRs promote active, ongoing

  14. T-DNA transfer and T-DNA integration efficiencies upon Arabidopsis thaliana root explant cocultivation and floral dip transformation.

    PubMed

    Ghedira, Rim; De Buck, Sylvie; Van Ex, Frédéric; Angenon, Geert; Depicker, Ann

    2013-12-01

    T-DNA transfer and integration frequencies during Agrobacterium-mediated root explant cocultivation and floral dip transformations of Arabidopsis thaliana were analyzed with and without selection for transformation-competent cells. Based on the presence or absence of CRE recombinase activity without or with the CRE T-DNA being integrated, transient expression versus stable transformation was differentiated. During root explant cocultivation, continuous light enhanced the number of plant cells competent for interaction with Agrobacterium and thus the number of transient gene expression events. However, in transformation competent plant cells, continuous light did not further enhance cotransfer or cointegration frequencies. Upon selection for root transformants expressing a first T-DNA, 43-69 % of these transformants showed cotransfer of another non-selected T-DNA in two different light regimes. However, integration of the non-selected cotransferred T-DNA occurred only in 19-46 % of these transformants, indicating that T-DNA integration in regenerating root cells limits the transformation frequencies. After floral dip transformation, transient T-DNA expression without integration could not be detected, while stable T-DNA transformation occurred in 0.5-1.3 % of the T1 seedlings. Upon selection for floral dip transformants with a first T-DNA, 8-34 % of the transformants showed cotransfer of the other non-selected T-DNA and in 93-100 % of them, the T-DNA was also integrated. Therefore, a productive interaction between the agrobacteria and the female gametophyte, rather than the T-DNA integration process, restricts the floral dip transformation frequencies. PMID:23975012

  15. Coulomb interactions and fermion condensation

    SciTech Connect

    Capstick, S.; Cutkosky, R.E.; Joensen, M.A. ); Wang, K.C. )

    1990-08-15

    The influence of the Coulomb interaction in states containing massless and flavorless fermion-antifermion pairs is studied, using a continuum formulation within the finite volume {ital S}{sup 3}. Several different forms for the Coulomb interaction are examined, including confining potentials as well as nonconfining potentials. The calculations show that if the interaction is strong enough, the Coulomb interaction leads to condensation of pairs, and that this condensation has a chiral character. The condensation does not depend on whether the interaction is confining. It is found that simplified variational approximations are not accurate enough for an adequate description of the states.

  16. Efficient gene transfer in C.elegans: extrachromosomal maintenance and integration of transforming sequences.

    PubMed Central

    Mello, C C; Kramer, J M; Stinchcomb, D; Ambros, V

    1991-01-01

    We describe a dominant behavioral marker, rol-6(su-1006), and an efficient microinjection procedure which facilitate the recovery of Caenorhabditis elegans transformants. We use these tools to study the mechanism of C.elegans DNA transformation. By injecting mixtures of genetically marked DNA molecules, we show that large extrachromosomal arrays assemble directly from the injected molecules and that homologous recombination drives array assembly. Appropriately placed double-strand breaks stimulated homologous recombination during array formation. Our data indicate that the size of the assembled transgenic structures determines whether or not they will be maintained extrachromosomally or lost. We show that low copy number extrachromosomal transformation can be achieved by adjusting the relative concentration of DNA molecules in the injection mixture. Integration of the injected DNA, though relatively rare, was reproducibly achieved when single-stranded oligonucleotide was co-injected with the double-stranded DNA. Images PMID:1935914

  17. Tensor Product Model Transformation Based Adaptive Integral-Sliding Mode Controller: Equivalent Control Method

    PubMed Central

    Zhao, Guoliang; Li, Hongxing

    2013-01-01

    This paper proposes new methodologies for the design of adaptive integral-sliding mode control. A tensor product model transformation based adaptive integral-sliding mode control law with respect to uncertainties and perturbations is studied, while upper bounds on the perturbations and uncertainties are assumed to be unknown. The advantage of proposed controllers consists in having a dynamical adaptive control gain to establish a sliding mode right at the beginning of the process. Gain dynamics ensure a reasonable adaptive gain with respect to the uncertainties. Finally, efficacy of the proposed controller is verified by simulations on an uncertain nonlinear system model. PMID:24453897

  18. A Unified Method of Finding Laplace Transforms, Fourier Transforms, and Fourier Series. [and] An Inversion Method for Laplace Transforms, Fourier Transforms, and Fourier Series. Integral Transforms and Series Expansions. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Units 324 and 325.

    ERIC Educational Resources Information Center

    Grimm, C. A.

    This document contains two units that examine integral transforms and series expansions. In the first module, the user is expected to learn how to use the unified method presented to obtain Laplace transforms, Fourier transforms, complex Fourier series, real Fourier series, and half-range sine series for given piecewise continuous functions. In…

  19. An integrating current transformer for fast extraction from the HIRFL-CSR main ring

    NASA Astrophysics Data System (ADS)

    Wu, Jun-Xia; Zheng, Jian-Hua; Zhao, Tie-Cheng; Mao, Rui-Shi; Yin, Yan; Yuan, You-Jin; Yang, Jian-Cheng

    2010-01-01

    For any experiment that uses the beam of an accelerator, monitoring the beam intensity is always an important concern. It is particularly useful if one can continuously measure the beam current without disturbing the beam. We report here on test experiments for an Integrating Current Transformer (ICT) used to measure fast extraction beams from the HIRFL-CSR main ring (CSRm). The laboratory tests and beam intensity measurement results are presented in this paper. The influence of the kicker noise is also analyzed.

  20. Auxiliary functions for molecular integrals with Slater-type orbitals. II. Gauss transform methods

    NASA Astrophysics Data System (ADS)

    Ema, I.; López, R.; Fernández, J. J.; Ramírez, G.; Rico, J. F.

    The Gauss transform of Slater-type orbitals is used to express several types of molecular integrals involving these functions in terms of simple auxiliary functions. After reviewing this transform and the way it can be combined with the shift operator technique, a master formula for overlap integrals is derived and used to obtain multipolar moments associated to fragments of two-center distributions and overlaps of derivatives of Slater functions. Moreover, it is proved that integrals involving two-center distributions and irregular harmonics placed at arbitrary points (which determine the electrostatic potential, field and field gradient, as well as higher order derivatives of the potential) can be expressed in terms of auxiliary functions of the same type as those appearing in the overlap. The recurrence relations and series expansions of these functions are thoroughly studied, and algorithms for their calculation are presented. The usefulness and efficiency of this procedure are tested by developing two independent codes: one for the derivatives of the overlap integrals with respect to the centers of the functions, and another for derivatives of the potential (electrostatic field, field gradient, and so forth) at arbitrary points.0

  1. Estimation of petrophysical and fluid properties using integral transforms in nuclear magnetic resonance.

    PubMed

    Gruber, Fred K; Venkataramanan, Lalitha; Habashy, Tarek M; Freed, Denise E

    2013-03-01

    In the past decade, low-field NMR relaxation and diffusion measurements in grossly inhomogeneous fields have been used to characterize properties of porous media, e.g., porosity and permeability. Pulse sequences such as CPMG, inversion and saturation recovery as well as diffusion editing have been used to estimate distribution functions of relaxation times and diffusion. Linear functionals of these distribution functions have been used to predict petro-physical and fluid properties like permeability, viscosity, fluid typing, etc. This paper describes an analysis method using integral transforms to directly compute linear functionals of the distributions of relaxation times and diffusion without first computing the distributions from the measured magnetization data. Different linear functionals of the distribution function can be obtained by choosing appropriate kernels in the integral transforms. There are two significant advantages of this approach over the traditional algorithm involving inversion of the distribution function from the measured data. First, it is a direct linear transform of the data. Thus, in contrast to the traditional analysis which involves inversion of an ill-conditioned, non-linear problem, the estimates from this new method are more accurate. Second, the uncertainty in the linear functional can be obtained in a straight-forward manner as a function of the signal-to-noise ratio (SNR) in the measured data. We demonstrate the performance of this method on simulated data. PMID:23369701

  2. Transformation of Chloroplast Ribosomal RNA Genes in Chlamydomonas: Molecular and Genetic Characterization of Integration Events

    PubMed Central

    Newman, S. M.; Boynton, J. E.; Gillham, N. W.; Randolph-Anderson, B. L.; Johnson, A. M.; Harris, E. H.

    1990-01-01

    Transformation of chloroplast ribosomal RNA (rRNA) genes in Chlamydomonas has been achieved by the biolistic process using cloned chloroplast DNA fragments carrying mutations that confer antibiotic resistance. The sites of exchange employed during the integration of the donor DNA into the recipient genome have been localized using a combination of antibiotic resistance mutations in the 16S and 23S rRNA genes and restriction fragment length polymorphisms that flank these genes. Complete or nearly complete replacement of a region of the chloroplast genome in the recipient cell by the corresponding sequence from the donor plasmid was the most common integration event. Exchange events between the homologous donor and recipient sequences occurred preferentially near the vector:insert junctions. Insertion of the donor rRNA genes and flanking sequences into one inverted repeat of the recipient genome was followed by intramolecular copy correction so that both copies of the inverted repeat acquired identical sequences. Increased frequencies of rRNA gene transformants were achieved by reducing the copy number of the chloroplast genome in the recipient cells and by decreasing the heterology between donor and recipient DNA sequences flanking the selectable markers. In addition to producing bona fide chloroplast rRNA transformants, the biolistic process induced mutants resistant to low levels of streptomycin, typical of nuclear mutations in Chlamydomonas. PMID:1981764

  3. Construction of the two-electron contribution to the Fock matrix by numerical integration

    NASA Astrophysics Data System (ADS)

    Losilla, Sergio A.; Mehine, Mooses M.; Sundholm, Dage

    2012-10-01

    A novel method to numerically calculate the Fock matrix is presented. The Coulomb operator is re-expressed as an integral identity, which is discretized. The discretization of the auxiliary t dimension separates the x, y, and z dependencies transforming the two-electron Coulomb integrals of Gaussian-type orbitals (GTO) to a linear sum of products of two-dimensional integrals. The s-type integrals are calculated analytically and integrals of the higher angular-momentum functions are obtained using recursion formulae. The contributions to the two-body Coulomb integrals obtained for each discrete t value can be evaluated independently. The two-body Fock matrix elements can be integrated numerically, using common sets of quadrature points and weights. The aim is to calculate Fock matrices of enough accuracy for electronic structure calculations. Preliminary calculations indicate that it is possible to achieve an overall accuracy of at least 10-12 E h using the numerical approach.

  4. Self-Consistent Sources for Integrable Equations Via Deformations of Binary Darboux Transformations

    NASA Astrophysics Data System (ADS)

    Chvartatskyi, Oleksandr; Dimakis, Aristophanes; Müller-Hoissen, Folkert

    2016-08-01

    We reveal the origin and structure of self-consistent source extensions of integrable equations from the perspective of binary Darboux transformations. They arise via a deformation of the potential that is central in this method. As examples, we obtain in particular matrix versions of self-consistent source extensions of the KdV, Boussinesq, sine-Gordon, nonlinear Schrödinger, KP, Davey-Stewartson, two-dimensional Toda lattice and discrete KP equation. We also recover a (2+1)-dimensional version of the Yajima-Oikawa system from a deformation of the pKP hierarchy. By construction, these systems are accompanied by a hetero binary Darboux transformation, which generates solutions of such a system from a solution of the source-free system and additionally solutions of an associated linear system and its adjoint. The essence of all this is encoded in universal equations in the framework of bidifferential calculus.

  5. Self-Consistent Sources for Integrable Equations Via Deformations of Binary Darboux Transformations

    NASA Astrophysics Data System (ADS)

    Chvartatskyi, Oleksandr; Dimakis, Aristophanes; Müller-Hoissen, Folkert

    2016-06-01

    We reveal the origin and structure of self-consistent source extensions of integrable equations from the perspective of binary Darboux transformations. They arise via a deformation of the potential that is central in this method. As examples, we obtain in particular matrix versions of self-consistent source extensions of the KdV, Boussinesq, sine-Gordon, nonlinear Schrödinger, KP, Davey-Stewartson, two-dimensional Toda lattice and discrete KP equation. We also recover a (2+1)-dimensional version of the Yajima-Oikawa system from a deformation of the pKP hierarchy. By construction, these systems are accompanied by a hetero binary Darboux transformation, which generates solutions of such a system from a solution of the source-free system and additionally solutions of an associated linear system and its adjoint. The essence of all this is encoded in universal equations in the framework of bidifferential calculus.

  6. Transformation of Ulva mutabilis (Chlorophyta) by vector plasmids integrating into the genome.

    PubMed

    Oertel, Wolfgang; Wichard, Thomas; Weissgerber, Adelheid

    2015-10-01

    A method for the stable transformation of the green marine macroalga Ulva mutabilis was developed based on vector plasmids integrating into the genome. By combination of the expression signals (promoter, enhancer, and transcriptional termination sequences) of a chromosomal rbcS gene from U. mutabilis with the bleomycin resistance gene (ble) from Streptoalloteichus hindustanus, a dominant selectable marker gene was constructed for the preparation of a series of E. coli-U. mutabilis shuttle vector plasmids. Special vectors were prepared for the introduction and expression of foreign genes in Ulva, for insertional mutagenesis and gene tagging by plasmid integration into the genome, and for protein tagging by the green fluorescent protein, as well as tools for posttranscriptional gene silencing and cosmid cloning to prepare genomic gene libraries for mutant gene complementation. The vectors were successfully tested in pilot experiments, where they were efficiently introduced into Ulva gametes, zoospores or protoplasts of somatic blade cells by treatment with Ca(2+) -ions and polyethylene glycol under isotonic conditions at low ionic strength. The parthenogenetically propagated phleomycin-resistant transformants of the mutant slender (sl) and the wildtype (wt) were demonstrated to be carrying the plasmids randomly integrated into the chromosomes often as tandem repeat clusters. PMID:26986891

  7. Integrated system for image storage, retrieval, and transmission using wavelet transform

    NASA Astrophysics Data System (ADS)

    Yu, Dan; Liu, Yawen; Mu, Ray Y.; Yang, Shi-Qiang

    1998-12-01

    Currently, much work has been done in the area of image storage and retrieval. However, the overall performance has been far from practical. A highly integrated wavelet-based image management system is proposed in this paper. By integrating wavelet-based solutions for image compression and decompression, content-based retrieval and progressive transmission, much higher performance can be achieved. The multiresolution nature of the wavelet transform has been proven to be a powerful tool to represent images. The wavelet transform decomposes the image into a set of subimages with different resolutions. From here three solutions for key aspects of image management are reached. The content-based image retrieval (CBIR) features of our system include the color, contour, texture, sample, keyword and topic information of images. The first four features can be naturally extracted from the wavelet transform coefficients. By scoring the similarity of users' requests with images in the database, those who have higher scores are noted and the user receives feedback. Image compression and decompression. Assuming that details at high resolution and diagonal directions are less visible to the human eye, a good compression ratio can be achieved. In each subimage, the wavelet coefficients are vector quantized (VQ), using the LGB algorithm, which is improved in our approach to accelerate the process. Higher compression ratio can be achieved with DPCM and entropy coding method applied together. With YIQ representation, color images can also be effectively compressed. There is a very low load on the network bandwidth by transmitting compressed image data across the network. Progressive transmission is possible by employment of the multiresolution nature of the wavelet, which makes the system respond faster and the user-interface more friendly. The system shows a high overall performance by exploring the excellent features of wavelet, and integrating key aspects of image management. An

  8. Standing wave integrated Fourier transform spectrometer for imaging spectrometry in the near infrared

    NASA Astrophysics Data System (ADS)

    Osowiecki, Gaël. D.; Madi, Mohammad; Shorubalko, Ivan; Philipoussis, Irène; Alberti, Edoardo; Scharf, Toralf; Herzig, Hans P.

    2015-09-01

    We show the miniaturization and parallelization of a scanning standing wave spectrometer with a long term goal of creating a compact imaging spectrometer. In our standing wave integrated Fourier transform spectrometer, light is injected with micro-lenses into several optical polymer waveguides. A piezo actuated mirror located at the waveguide end-facet can shift the interferogram to increase its sampling frequency. The spatial distribution of the standing wave intensity inside the waveguide is partially scattered out of the plane by a periodic metallic grating and recorded by a CCD camera. We present spectra acquisition for six adjacent waveguides simultaneously at a wavelength of 632.8 nm.

  9. Integrated frequency comb source based Hilbert transformer for wideband microwave photonic phase analysis.

    PubMed

    Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

    2015-08-24

    We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response. PMID:26368182

  10. Integrated transformations of plant biomass to valuable chemicals, biodegradable polymers and nanoporous carbons

    NASA Astrophysics Data System (ADS)

    Kuznetsov, B. N.; Chesnokov, N. V.; Taraban'ko, V. E.; Kuznetsova, S. A.; Petrov, A. V.

    2013-03-01

    Integrated transformations of wood biomass to valuable chemicals and materials are described. They include the main biomass components separation, the conversion of cellulose to glucose, levulinic acid, biodegradable polymers and lignin - to nanoporous carbons. For wood fractionation on pure cellulose and low molecular mass lignin the methods of catalytic oxidation and exploded autohydrolysis are used. The processes of acid-catalysed hydrolysis of cellulose to glucose and levulinic acid were optimized. New methods of biodegradable polymers synthesis from lactone of levulinic acid and nanoporous carbons from lignin were suggested.

  11. Time transformations and Cowell's method. [for numerical integration of satellite motion equations

    NASA Technical Reports Server (NTRS)

    Velez, C. E.; Hilinski, S.

    1978-01-01

    The precise numerical integration of Cowell's equations of satellite motion is frequently performed with an independent variable s defined by an equation of the form dt = cr to the n-th power ds, where t represents time, r the radial distance from the center of attraction, c is a constant, and n is a parameter. This has been primarily motivated by the 'uniformizing' effects of such a transformation resulting in desirable 'analytic' stepsize control for elliptical orbits. This report discusses the 'proper' choice of the parameter n defining the independent variable s for various types of orbits and perturbation models, and develops a criterion for its selection.

  12. Large-scale, white-light, transformation optics using integral imaging

    NASA Astrophysics Data System (ADS)

    Oxburgh, Stephen; White, Chris D.; Antoniou, Georgios; Orife, Ejovbokoghene; Sharpe, Tim; Courtial, Johannes

    2016-04-01

    We describe a way to realise transformation-optical devices from structures of micro-structured sheets called generalised confocal lenslet arrays. The resulting devices should work for all visible light, and they should be relatively easy and cheap to (mass-)produce on the scale of metres, but they suffer from field-of-view limitations and significant transmission loss. Furthermore, the mapping between electromagnetic space and physical space is not through stigmatic imaging, but integral imaging. As an example application of this technology, we design and simulate an architectural window that cloaks insulation material with the aim of reducing heat loss.

  13. Third-order symplectic integration method with inverse time dispersion transform for long-term simulation

    NASA Astrophysics Data System (ADS)

    Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing

    2016-06-01

    The symplectic integration method is popular in high-accuracy numerical simulations when discretizing temporal derivatives; however, it still suffers from time-dispersion error when the temporal interval is coarse, especially for long-term simulations and large-scale models. We employ the inverse time dispersion transform (ITDT) to the third-order symplectic integration method to reduce the time-dispersion error. First, we adopt the pseudospectral algorithm for the spatial discretization and the third-order symplectic integration method for the temporal discretization. Then, we apply the ITDT to eliminate time-dispersion error from the synthetic data. As a post-processing method, the ITDT can be easily cascaded in traditional numerical simulations. We implement the ITDT in one typical exiting third-order symplectic scheme and compare its performances with the performances of the conventional second-order scheme and the rapid expansion method. Theoretical analyses and numerical experiments show that the ITDT can significantly reduce the time-dispersion error, especially for long travel times. The implementation of the ITDT requires some additional computations on correcting the time-dispersion error, but it allows us to use the maximum temporal interval under stability conditions; thus, its final computational efficiency would be higher than that of the traditional symplectic integration method for long-term simulations. With the aid of the ITDT, we can obtain much more accurate simulation results but with a lower computational cost.

  14. TRANSVERSE MERCATOR MAP PROJECTION OF THE SPHEROID USING TRANSFORMATION OF THE ELLIPTIC INTEGRAL

    NASA Technical Reports Server (NTRS)

    Wallis, D. E.

    1994-01-01

    the (irreducible) Incomplete Elliptic Integral of the 2nd Kind, the value for the tangent of one half the amplitude of the Elliptic Integral of the 2nd Kind is now known. The elliptic integral may now be computed by any desired method, and the result will be the Gauss-Kruger Transverse Mercator Projection. This result is a consequence of the fact that these steps produce a computation of real distance along the image (in the plane) of the principal meridian, and an analytic continuation of the distance at points that don't lie on the principal meridian. The elliptic-integral method used by this program is one of the "transformations of the elliptic integral" (similar to Landen's Transformation), appearing in standard handbooks of mathematical functions. Only elementary transcendental functions are utilized. The program output is the conventional (as used by the mapping agencies) cartesian coordinates, in meters, of the Transverse Mercator projection. The origin is at the intersection of the principal meridian and the equator. This FORTRAN77 program was developed on an IBM PC series computer equipped with an Intel Math Coprocessor. Double precision complex arithmetic and transcendental functions are needed to support a projection accuracy of 1 mm. Because such functions are not usually part of the FORTRAN library, the needed functions have been explicitly programmed and included in the source code. The program was developed in 1989. TRANSVERSE MERCATOR MAP PROJECTION OF THE SPHEROID USING TRANSFORMATIONS OF THE ELLIPTIC INTEGRAL is a copyrighted work with all copyright vested in NASA.

  15. On Coulomb collisions in bi-Maxwellian plasmas

    SciTech Connect

    Hellinger, Petr; Travnicek, Pavel M.

    2009-05-15

    Collisional momentum and energy transport in bi-Maxwellian plasmas with a drift velocity along the ambient magnetic field are calculated from both the Fokker-Planck and Boltzmann integral approximations. The transport coefficients obtained from the two approaches are identical to the leading order (proportional to the Coulomb logarithm) and are presented here in a closed form involving generalized double hypergeometric functions.

  16. Using the Screened Coulomb Potential to Illustrate the Variational Method

    ERIC Educational Resources Information Center

    Zuniga, Jose; Bastida, Adolfo; Requena, Alberto

    2012-01-01

    The screened Coulomb potential, or Yukawa potential, is used to illustrate the application of the single and linear variational methods. The trial variational functions are expressed in terms of Slater-type functions, for which the integrals needed to carry out the variational calculations are easily evaluated in closed form. The variational…

  17. Entropic Corrections to Coulomb's Law

    NASA Astrophysics Data System (ADS)

    Hendi, S. H.; Sheykhi, A.

    2012-04-01

    Two well-known quantum corrections to the area law have been introduced in the literatures, namely, logarithmic and power-law corrections. Logarithmic corrections, arises from loop quantum gravity due to thermal equilibrium fluctuations and quantum fluctuations, while, power-law correction appears in dealing with the entanglement of quantum fields in and out the horizon. Inspired by Verlinde's argument on the entropic force, and assuming the quantum corrected relation for the entropy, we propose the entropic origin for the Coulomb's law in this note. Also we investigate the Uehling potential as a radiative correction to Coulomb potential in 1-loop order and show that for some value of distance the entropic corrections of the Coulomb's law is compatible with the vacuum-polarization correction in QED. So, we derive modified Coulomb's law as well as the entropy corrected Poisson's equation which governing the evolution of the scalar potential ϕ. Our study further supports the unification of gravity and electromagnetic interactions based on the holographic principle.

  18. Coulomb problem for vector particles : Energy spectrum.

    SciTech Connect

    Kuchiev, M. Yu.; Flambaum, V. V.; Physics; Univ. of South Wales

    2006-05-31

    The Coulomb problem for vector bosons W{+-} incorporates a well-known difficulty; the charge of the boson localized in a close vicinity of the attractive Coulomb center proves to be infinite. The paradox is shown to be resolved by the QED vacuum polarization, which brings in a strong effective repulsion that eradicates the infinite charge of the boson on the Coulomb center. This property allows one to define the Coulomb problem for vector bosons properly.

  19. Nonstationary multistate Coulomb and multistate exponential models for nonadiabatic transitions

    SciTech Connect

    Ostrovsky, V. N.

    2003-07-01

    The nonstationary Schroedinger equation is considered in a finite basis of states. The model Hamiltonian matrix corresponds to a single diabatic potential curve with a Coulombic {approx}1/t time dependence. An arbitrary number of other diabatic potential curves are flat, i.e., time independent and have arbitrary energies. Related states are coupled by constant interactions with the Coulomb state. The resulting nonstationary Schroedinger equation is solved by the method of contour integral. Probabilities of transitions to any other state are obtained as t{yields}{infinity} in a simple analytical form for the case when the Coulomb state is populated initially (at instant of time t{yields}+0). The formulas apply both to the cases when a horizontal diabatic potential curve is crossed by the Coulomb one and to a noncrossing situation. In the limit of weak coupling, the transition probabilities are interpreted in terms of a sequence of pairwise Landau-Zener-type transitions. Mapping of the Coulomb model onto an exactly solvable exponential multistate model is established. For the special two-state case, the well-known Nikitin model is recovered.

  20. Integrative genomic testing of cancer survival using semiparametric linear transformation models.

    PubMed

    Huang, Yen-Tsung; Cai, Tianxi; Kim, Eunhee

    2016-07-20

    The wide availability of multi-dimensional genomic data has spurred increasing interests in integrating multi-platform genomic data. Integrative analysis of cancer genome landscape can potentially lead to deeper understanding of the biological process of cancer. We integrate epigenetics (DNA methylation and microRNA expression) and gene expression data in tumor genome to delineate the association between different aspects of the biological processes and brain tumor survival. To model the association, we employ a flexible semiparametric linear transformation model that incorporates both the main effects of these genomic measures as well as the possible interactions among them. We develop variance component tests to examine different coordinated effects by testing various subsets of model coefficients for the genomic markers. A Monte Carlo perturbation procedure is constructed to approximate the null distribution of the proposed test statistics. We further propose omnibus testing procedures to synthesize information from fitting various parsimonious sub-models to improve power. Simulation results suggest that our proposed testing procedures maintain proper size under the null and outperform standard score tests. We further illustrate the utility of our procedure in two genomic analyses for survival of glioblastoma multiforme patients. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26887583

  1. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    NASA Astrophysics Data System (ADS)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  2. Seamless integration of global Dirichlet-to-Neumann boundary condition and spectral elements for transformation electromagnetics

    NASA Astrophysics Data System (ADS)

    Yang, Zhiguo; Wang, Li-Lian; Rong, Zhijian; Wang, Bo; Zhang, Baile

    2016-04-01

    In this paper, we present an efficient spectral-element method (SEM) for solving general two-dimensional Helmholtz equations in anisotropic media, with particular applications in accurate simulation of polygonal invisibility cloaks, concentrators and circular rotators arisen from the field of transformation electromagnetics (TE). In practice, we adopt a transparent boundary condition (TBC) characterized by the Dirichlet-to-Neumann (DtN) map to reduce wave propagation in an unbounded domain to a bounded domain. We then introduce a semi-analytic technique to integrate the global TBC with local curvilinear elements seamlessly, which is accomplished by using a novel elemental mapping and analytic formulas for evaluating global Fourier coefficients on spectral-element grids exactly. From the perspective of TE, an invisibility cloak is devised by a singular coordinate transformation of Maxwell's equations that leads to anisotropic materials coating the cloaked region to render any object inside invisible to observers outside. An important issue resides in the imposition of appropriate conditions at the outer boundary of the cloaked region, i.e., cloaking boundary conditions (CBCs), in order to achieve perfect invisibility. Following the spirit of [48], we propose new CBCs for polygonal invisibility cloaks from the essential "pole" conditions related to singular transformations. This allows for the decoupling of the governing equations of inside and outside the cloaked regions. With this efficient spectral-element solver at our disposal, we can study the interesting phenomena when some defects and lossy or dispersive media are placed in the cloaking layer of an ideal polygonal cloak.

  3. A new method to calculate the beam charge for an integrating current transformer

    SciTech Connect

    Wu Yuchi; Han Dan; Zhu Bin; Dong Kegong; Tan Fang; Gu Yuqiu

    2012-09-15

    The integrating current transformer (ICT) is a magnetic sensor widely used to precisely measure the charge of an ultra-short-pulse charged particle beam generated by traditional accelerators and new laser-plasma particle accelerators. In this paper, we present a new method to calculate the beam charge in an ICT based on circuit analysis. The output transfer function shows an invariable signal profile for an ultra-short electron bunch, so the function can be used to evaluate the signal quality and calculate the beam charge through signal fitting. We obtain a set of parameters in the output function from a standard signal generated by an ultra-short electron bunch (about 1 ps in duration) at a radio frequency linear electron accelerator at Tsinghua University. These parameters can be used to obtain the beam charge by signal fitting with excellent accuracy.

  4. Feasibility investigation of integrated optics Fourier transform devices. [holographic subtraction for multichannel data preprocessing

    NASA Technical Reports Server (NTRS)

    Verber, C. M.; Vahey, D. W.; Wood, V. E.; Kenan, R. P.; Hartman, N. F.

    1977-01-01

    The possibility of producing an integrated optics data processing device based upon Fourier transformations or other parallel processing techniques, and the ways in which such techniques may be used to upgrade the performance of present and projected NASA systems were investigated. Activities toward this goal include; (1) production of near-diffraction-limited geodesic lenses in glass waveguides; (2) development of grinding and polishing techniques for the production of geodesic lenses in LiNbO3 waveguides; (3) development of a characterization technique for waveguide lenses; and (4) development of a theory for corrected aspheric geodesic lenses. A holographic subtraction system was devised which should be capable of rapid on-board preprocessing of a large number of parallel data channels. The principle involved is validated in three demonstrations.

  5. Binary Darboux Transformations in Bidifferential Calculus and Integrable Reductions of Vacuum Einstein Equations

    NASA Astrophysics Data System (ADS)

    Dimakis, Aristophanes; Müller-Hoissen, Folkert

    2013-02-01

    We present a general solution-generating result within the bidifferential calculus approach to integrable partial differential and difference equations, based on a binary Darboux-type transformation. This is then applied to the non-autonomous chiral model, a certain reduction of which is known to appear in the case of the D-dimensional vacuum Einstein equations with D-2 commuting Killing vector fields. A large class of exact solutions is obtained, and the aforementioned reduction is implemented. This results in an alternative to the well-known Belinski-Zakharov formalism. We recover relevant examples of space-times in dimensions four (Kerr-NUT, Tomimatsu-Sato) and five (single and double Myers-Perry black holes, black saturn, bicycling black rings).

  6. Redatuming controlled-source electromagnetic data using Stratton-Chu type integral transformations

    NASA Astrophysics Data System (ADS)

    Zhdanov, Michael; Cai, Hongzhu

    2016-03-01

    We present a new method of analyzing controlled-source electromagnetic (CSEM) data based on redatuming of the observed data from the actual receivers into the virtual receivers. We use the Stratton-Chu type integral transform to calculate the EM field in the virtual receivers. The virtual receivers can be placed at any desirable position, including close to the target, which increases the sensitivity of the EM data to the target. The developed method provides an effective model-based interpolation/extrapolation tool for electromagnetic field data. This paper demonstrates that redatuming can be used for designing the optimized CSEM survey configuration. The numerical examples, for the Kevin Dome Electromagnetic Project Site, illustrate the practical effectiveness of the developed method.

  7. Reconstructing Folding Energy Landscape Profiles from Nonequilibrium Pulling Curves with an Inverse Weierstrass Integral Transform

    NASA Astrophysics Data System (ADS)

    Engel, Megan C.; Ritchie, Dustin B.; Foster, Daniel A. N.; Beach, Kevin S. D.; Woodside, Michael T.

    2014-12-01

    The energy landscapes that drive structure formation in biopolymers are difficult to measure. Here we validate experimentally a novel method to reconstruct landscape profiles from single-molecule pulling curves using an inverse Weierstrass transform (IWT) of the Jarzysnki free-energy integral. The method was applied to unfolding measurements of a DNA hairpin, replicating the results found by the more-established weighted histogram (WHAM) and inverse Boltzmann methods. Applying both WHAM and IWT methods to reconstruct the folding landscape for a RNA pseudoknot having a stiff energy barrier, we found that landscape features with sharper curvature than the force probe stiffness could not be recovered with the IWT method. The IWT method is thus best for analyzing data from stiff force probes such as atomic force microscopes.

  8. Three New (2+1)-dimensional Integrable Systems and Some Related Darboux Transformations

    NASA Astrophysics Data System (ADS)

    Guo, Xiu-Rong

    2016-06-01

    We introduce two operator commutators by using different-degree loop algebras of the Lie algebra A1, then under the framework of zero curvature equations we generate two (2+1)-dimensional integrable hierarchies, including the (2+1)-dimensional shallow water wave (SWW) hierarchy and the (2+1)-dimensional Kaup-Newell (KN) hierarchy. Through reduction of the (2+1)-dimensional hierarchies, we get a (2+1)-dimensional SWW equation and a (2+1)-dimensional KN equation. Furthermore, we obtain two Darboux transformations of the (2+1)-dimensional SWW equation. Similarly, the Darboux transformations of the (2+1)-dimensional KN equation could be deduced. Finally, with the help of the spatial spectral matrix of SWW hierarchy, we generate a (2+1) heat equation and a (2+1) nonlinear generalized SWW system containing inverse operators with respect to the variables x and y by using a reduction spectral problem from the self-dual Yang-Mills equations. Supported by the National Natural Science Foundation of China under Grant No. 11371361, the Shandong Provincial Natural Science Foundation of China under Grant Nos. ZR2012AQ011, ZR2013AL016, ZR2015EM042, National Social Science Foundation of China under Grant No. 13BJY026, the Development of Science and Technology Project under Grant No. 2015NS1048 and A Project of Shandong Province Higher Educational Science and Technology Program under Grant No. J14LI58

  9. Nitrogen transformations and mass balance in an integrated constructed wetland treating domestic wastewater.

    PubMed

    Dzakpasu, Mawuli; Scholz, Miklas; McCarthy, Valerie; Jordan, Siobhán

    2014-01-01

    Nitrogen (N) transformations and removal in integrated constructed wetlands (ICWs) are often high, but the contributions of various pathways, including nitrification/denitrification, assimilation by plants and sediment storage, remain unclear. This study quantified the contributions of different N removal pathways in a typical multi-celled ICW system treating domestic wastewater. Findings showed near complete average total N retention of circa 95% at 102.3 g m⁻² yr⁻¹ during the 4-year period of operation. Variations in total N and NH4-N removal rates were associated with effluent flow volume rates and seasons. According to the mass balance estimation, assimilation by plants and sediment/soil storage accounted for approximately 23% and 20%, respectively, of the total N load removal. These were the major N removal route besides microbial transformations. Thus, the combination of plants with high biomass production offer valuable opportunities for improving ICW performance. The retrieval and use of sequestered N in the ICW sediment/soils require coherent management and provide innovative and valuable opportunities. PMID:25401313

  10. Coulomb dissociation of N,2120

    NASA Astrophysics Data System (ADS)

    Röder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamaño, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkäll, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Datta Pramanik, Ushasi; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhäuser, Roman; Göbel, Kathrin; Golubev, Pavel; Gonzalez Diaz, D.; Hagdahl, Julius; Heftrich, Tanja; Heil, Michael; Heine, Marcel; Heinz, Andreas; Henriques, Ana; Holl, Matthias; Ickert, G.; Ignatov, Alexander; Jakobsson, Bo; Johansson, Hâkan; Jonson, Björn; Kalantar-Nayestanaki, Nasser; Kanungo, Rituparna; Kelic-Heil, Aleksandra; Knöbel, Ronja; Kröll, Thorsten; Krücken, Reiner; Kurcewicz, J.; Kurz, Nikolaus; Labiche, Marc; Langer, Christoph; Le Bleis, Tudi; Lemmon, Roy; Lepyoshkina, Olga; Lindberg, Simon; Machado, Jorge; Marganiec, Justyna; Mostazo Caro, Magdalena; Movsesyan, Alina; Najafi, Mohammad Ali; Nilsson, Thomas; Nociforo, Chiara; Panin, Valerii; Paschalis, Stefanos; Perea, Angel; Petri, Marina; Pietri, S.; Plag, Ralf; Prochazka, A.; Rahaman, Md. Anisur; Rastrepina, Ganna; Reifarth, Rene; Ribeiro, Guillermo; Ricciardi, M. Valentina; Rigollet, Catherine; Riisager, Karsten; Rossi, Dominic; Sanchez del Rio Saez, Jose; Savran, Deniz; Scheit, Heiko; Simon, Haik; Sorlin, Olivier; Stoica, V.; Streicher, Branislav; Taylor, Jon; Tengblad, Olof; Terashima, Satoru; Thies, Ronja; Togano, Yasuhiro; Uberseder, Ethan; Van de Walle, J.; Velho, Paulo; Volkov, Vasily; Wagner, Andreas; Wamers, Felix; Weick, Helmut; Weigand, Mario; Wheldon, Carl; Wilson, G.; Wimmer, Christine; Winfield, J. S.; Woods, Philip; Yakorev, Dmitry; Zhukov, Mikhail; Zilges, Andreas; Zuber, Kai; R3B Collaboration

    2016-06-01

    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N,2120 are reported. Relativistic N,2120 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the 19N (n ,γ )20N and 20N (n ,γ ) 21N excitation functions and thermonuclear reaction rates have been determined. The 19 (n ,γ )20N rate is up to a factor of 5 higher at T <1 GK with respect to previous theoretical calculations, leading to a 10% decrease in the predicted fluorine abundance.

  11. Coulomb Energies in ^18Ne

    NASA Astrophysics Data System (ADS)

    Sherr, R.; Fortune, H. T.

    1998-10-01

    Coulomb energies of the ^18Ne mirrors of the levels of ^18O vary considerably from state to state, an effect understood as arising from their different configurations. All the low-lying positive-parity states in these nuclei can be described in terms of two nucleons coupled to an ^16O core plus a collective component (most probably four-particle two-hole (4p-2h)). We have computed Coulomb energies using one such formulation(Lawson, Serduke and Fortune, Phys. Rev. C 14), 1245 (1976).. Two-particle energies arise from coupling a neutron to single-particle states of ^17O, and a proton to the mirror states of ^17F. For the 4p-2h component, we use the ^14O-^14C mass difference, plus a ph Coulomb term(Sherr and Bertsch, Phys. Rev. C 12), 1671 (1975).. Agreement is perhaps slightly better than another such attempt(Nero, Adelberger and Dietrich, Phys. Rev. C 24), 1864 (1981). using wave functions from Benson and Flowers.

  12. The conceptual basis of mathematics in cardiology III: linear systems theory and integral transforms.

    PubMed

    Bates, Jason H T; Sobel, Burton E

    2003-05-01

    This is the third in a series of four articles developed for the readers of Coronary Artery Disease. Without language ideas cannot be articulated. What may not be so immediately obvious is that they cannot be formulated either. One of the essential languages of cardiology is mathematics. Unfortunately, medical education does not emphasize, and in fact, often neglects empowering physicians to think mathematically. Reference to statistics, conditional probability, multicompartmental modeling, algebra, calculus and transforms is common but often without provision of genuine conceptual understanding. At the University of Vermont College of Medicine, Professor Bates developed a course designed to address these deficiencies. The course covered mathematical principles pertinent to clinical cardiovascular and pulmonary medicine and research. It focused on fundamental concepts to facilitate formulation and grasp of ideas.This series of four articles was developed to make the material available for a wider audience. The articles will be published sequentially in Coronary Artery Disease. Beginning with fundamental axioms and basic algebraic manipulations they address algebra, function and graph theory, real and complex numbers, calculus and differential equations, mathematical modeling, linear system theory and integral transforms and statistical theory. The principles and concepts they address provide the foundation needed for in-depth study of any of these topics. Perhaps of even more importance, they should empower cardiologists and cardiovascular researchers to utilize the language of mathematics in assessing the phenomena of immediate pertinence to diagnosis, pathophysiology and therapeutics. The presentations are interposed with queries (by Coronary Artery Disease abbreviated as CAD) simulating the nature of interactions that occurred during the course itself. Each article concludes with one or more examples illustrating application of the concepts covered to

  13. Exogenous Gene Integration for Microalgal Cell Transformation Using a Nanowire-Incorporated Microdevice.

    PubMed

    Bae, Sunwoong; Park, Seunghye; Kim, Jung; Choi, Jong Seob; Kim, Kyung Hoon; Kwon, Donguk; Jin, EonSeon; Park, Inkyu; Kim, Do Hyun; Seo, Tae Seok

    2015-12-16

    Superior green algal cells showing high lipid production and rapid growth rate are considered as an alternative for the next generation green energy resources. To achieve the biomass based energy generation, transformed microalgae with superlative properties should be developed through genetic engineering. Contrary to the normal cells, microalgae have rigid cell walls, so that target gene delivery into cells is challengeable. In this study, we report a ZnO nanowire-incorporated microdevice for a high throughput microalgal transformation. The proposed microdevice was equipped with not only a ZnO nanowire in the microchannel for gene delivery into cells but also a pneumatic polydimethylsiloxane (PDMS) microvalve to modulate the cellular attachment and detachment from the nanowire. As a model, hygromycin B resistance gene cassette (Hyg3) was functionalized on the hydrothermally grown ZnO nanowires through a disulfide bond and released into green algal cells, Chlamydomonas reinhardtii, by reductive cleavage. During Hyg3 gene delivery, a monolithic PDMS membrane was bent down, so that algal cells were pushed down toward ZnO nanowires. The supply of vacuum in the pneumatic line made the PDMS membrane bend up, enabling the gene delivered algal cells to be recovered from the outlet of the microchannel. We successfully confirmed Hyg3 gene integrated in microalgae by amplifying the inserted gene through polymerase chain reaction (PCR) and DNA sequencing. The efficiency of the gene delivery to algal cells using the ZnO nanowire-incorporated microdevice was 6.52 × 10(4)- and 9.66 × 10(4)-fold higher than that of a traditional glass bead beating and electroporation. PMID:26584003

  14. PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Neilson, David; Senatore, Gaetano

    2009-05-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas

  15. Some results on the integral transforms and applications to differential equations

    SciTech Connect

    Eltayeb, Hassan; Kilicman, Adem

    2010-11-11

    In this paper we give some remark about the relationship between Sumudu and Laplace transforms, further; for the comparison purpose, we apply both transforms to solve partial differential equations to see the differences and similarities.

  16. Leading Education Reform Initiatives: How SWIFT (Schoolwide Integrated Framework for Transformation) Coordinates and Enhances Impact. Issue Brief #2

    ERIC Educational Resources Information Center

    Kingston, Mary; Richards, Curtis; Blank, Rolf; Stonemeier, Jennifer; Trader, Barbara; East, Bill

    2014-01-01

    In this Issue Brief we discuss the impact that the Schoolwide Integrated Framework for Transformation (SWIFT) has on improving the outcomes of several current federal, state, district, and school education reform initiatives. Federal initiatives include Race to the Top, School Improvement Grants, and Campaign for Grade-Level Reading; Common Core…

  17. PLANE-INTEGRATED OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROMETRY METHODOLOGY FOR ANAEROBIC SWINE LAGOON EMISSION MEASUREMENTS

    EPA Science Inventory

    Emissions of ammonia and methane from an anaerobic lagoon at a swine animal feeding operation were evaluated five times over a period of two years. The plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) methodology was used to transect the plume at ...

  18. Elastic Coulomb breakup of 34Na

    NASA Astrophysics Data System (ADS)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  19. An entropic understanding of Coulomb force

    NASA Astrophysics Data System (ADS)

    Cho, Jin-Ho; Kim, Hyosung

    2012-02-01

    Exploiting Verlinde's proposal on the entropic understanding of Newton's law, we show that Coulomb force could also be understood as an entropically emergent force (rather than as a fundamental force). We apply Kaluza-Klein idea to Verlinde's formalism to obtain Coulomb interaction in the lower dimensions. The kinematics concerning the Kaluza-Klein momenta separates the interaction due to the momentum flow from the gravitational interaction. The momentum-charge conversion relation results in the precise form of Coulomb interaction.

  20. Transforming Healthcare Delivery: Integrating Dynamic Simulation Modelling and Big Data in Health Economics and Outcomes Research.

    PubMed

    Marshall, Deborah A; Burgos-Liz, Lina; Pasupathy, Kalyan S; Padula, William V; IJzerman, Maarten J; Wong, Peter K; Higashi, Mitchell K; Engbers, Jordan; Wiebe, Samuel; Crown, William; Osgood, Nathaniel D

    2016-02-01

    In the era of the Information Age and personalized medicine, healthcare delivery systems need to be efficient and patient-centred. The health system must be responsive to individual patient choices and preferences about their care, while considering the system consequences. While dynamic simulation modelling (DSM) and big data share characteristics, they present distinct and complementary value in healthcare. Big data and DSM are synergistic-big data offer support to enhance the application of dynamic models, but DSM also can greatly enhance the value conferred by big data. Big data can inform patient-centred care with its high velocity, volume, and variety (the three Vs) over traditional data analytics; however, big data are not sufficient to extract meaningful insights to inform approaches to improve healthcare delivery. DSM can serve as a natural bridge between the wealth of evidence offered by big data and informed decision making as a means of faster, deeper, more consistent learning from that evidence. We discuss the synergies between big data and DSM, practical considerations and challenges, and how integrating big data and DSM can be useful to decision makers to address complex, systemic health economics and outcomes questions and to transform healthcare delivery. PMID:26497003

  1. Integration or transformation? Looking in the future of Information and Communication Technology in education in Vietnam.

    PubMed

    Peeraer, Jef; Van Petegem, Peter

    2015-02-01

    Over the last two decades, crucial factors for Information and Communication Technology (ICT) in education have improved significantly in Vietnam. Nevertheless, it is clear that, as in other countries, no educational revolution is taking place. We argue that there is a need for a broad dialogue on the future of ICT in education in Vietnam as discussion of ideas about future possibilities can be instrumental in rationalizing and generating educational change. We explore how a group of key players representing the public and private sector as well as development partners in the field look at the future of ICT in education in the country. Following the Delphi method, these key players assessed in different survey rounds the current situation of ICT in education, identified a series of targets and were asked to assess these targets in respect of their importance. The key players reached a consensus that the purpose of technology integration is to achieve learning goals and enhance learning. However, there is more controversy on targets that could potentially transform education practice in Vietnam. We discuss the value of the Delphi technique and argue for increased participation of all involved stakeholders in policy development on ICT in education. PMID:25305806

  2. Coulomb Dissociation of 27P

    NASA Astrophysics Data System (ADS)

    Beceiro Novo, S.; Sümmerer, K.; Cortina-Gil, D.; Wimmer, C.; Plag, R.; Alvarez-Pol, H.; Aumann, T.; Behr, K.; Boretzky, K.; Casarejos, E.; Chatillon, A.; Datta-Pramanik, U.; Elekes, Z.; Fulop, Z.; Galaviz, D.; Geissel, H.; Giron, S.; Greife, U.; Hammache, F.; Heil, M.; Hoffman, J.; Johansson, H.; Karagiannis, C.; Kiselev, O.; Kurz, N.; Larsson, K.; Le Bleis, T.; Litvinov, Y.; Mahata, K.; Muentz, C.; Nociforo, C.; Ott, W.; Paschalis, S.; Prokopowicz, W.; Rodriguez-Tajes, C.; Rossi, D.; Simon, H.; Stanoiu, M.; Stroth, J.; Typel, S.; Wagner, A.; Wamers, F.; Weick, H.

    2012-09-01

    In this work the astrophysical 26Si(p,γ)27P reaction is studied using the Coulomb dissociation technique. We performed a 27P Coulomb Dissociation experiment at GSI, Darmstadt (28 May-5 June 2007) using the ALADIN-LAND setup which allows complete-kinematic studies. A secondary 27P beam at 498 AMeV impinging a 515mg/cm2 Pb target was used. The relative energy of the outgoing system (26Si+p) is measured obtaining the resonant states of the 27P. Preliminary results show four resonant states measured at 0.36±0.07, 0.88±0.09, 1.5±0.2, 2.3±0.3 MeV and evidence of a higher state at around 3.1 MeV. The preliminary total cross section obtained for relative energies between 0 and 3 MeV has been measured and yields 55±7 mb.

  3. Poisson Green's function method for increased computational efficiency in numerical calculations of Coulomb coupling elements

    NASA Astrophysics Data System (ADS)

    Zimmermann, Anke; Kuhn, Sandra; Richter, Marten

    2016-01-01

    Often, the calculation of Coulomb coupling elements for quantum dynamical treatments, e.g., in cluster or correlation expansion schemes, requires the evaluation of a six dimensional spatial integral. Therefore, it represents a significant limiting factor in quantum mechanical calculations. If the size or the complexity of the investigated system increases, many coupling elements need to be determined. The resulting computational constraints require an efficient method for a fast numerical calculation of the Coulomb coupling. We present a computational method to reduce the numerical complexity by decreasing the number of spatial integrals for arbitrary geometries. We use a Green's function formulation of the Coulomb coupling and introduce a generalized scalar potential as solution of a generalized Poisson equation with a generalized charge density as the inhomogeneity. That enables a fast calculation of Coulomb coupling elements and, additionally, a straightforward inclusion of boundary conditions and arbitrarily spatially dependent dielectrics through the Coulomb Green's function. Particularly, if many coupling elements are included, the presented method, which is not restricted to specific symmetries of the model, presents a promising approach for increasing the efficiency of numerical calculations of the Coulomb interaction. To demonstrate the wide range of applications, we calculate internanostructure couplings, such as the Förster coupling, and illustrate the inclusion of symmetry considerations in the method for the Coulomb coupling between bound quantum dot states and unbound continuum states.

  4. Calculation of proton-deuteron breakup reactions including the Coulomb interaction between the two protons.

    PubMed

    Deltuva, A; Fonseca, A C; Sauer, P U

    2005-08-26

    The Coulomb interaction between the two protons is fully included in the calculation of proton-deuteron breakup with realistic interactions for the first time. The hadron dynamics is based on the purely nucleonic charge-dependent (CD) Bonn potential and its realistic extension CD Bonn +Delta to a coupled-channel two-baryon potential, allowing for single virtual Delta-isobar excitation. Calculations are done using integral equations in momentum space. The screening and renormalization approach is employed for including the Coulomb interaction. The Coulomb effect on breakup observables is seen at all energies in particular kinematic regimes. PMID:16197210

  5. Phase controlled integrated interferometric single-sideband filter based on planar Bragg gratings implementing photonic Hilbert transform.

    PubMed

    Sima, Chaotan; Gates, J C; Rogers, H L; Mennea, P L; Holmes, C; Zervas, M N; Smith, P G R

    2013-03-01

    The monolithically integrated all-optical single-sideband (SSB) filter based on photonic Hilbert transform and planar Bragg gratings is proposed and experimentally demonstrated. An SSB suppression of 12 dB at 6 GHz and sideband switching are achieved via thermal tuning. An X-coupler, photonic Hilbert transformer, flat top reflector, and a micro heater are incorporated in a single silicon-on-silica substrate. The device can be thermally tuned by the micro heater on top of the channel waveguide. The device is fabricated using a combination of direct UV grating writing technology and photolithography. PMID:23455279

  6. An implicit fast Fourier transform method for integration of the time dependent Schrodinger equation

    SciTech Connect

    Riley, M.E.; Ritchie, A.B.

    1997-12-31

    One finds that the conventional exponentiated split operator procedure is subject to difficulties when solving the time-dependent Schrodinger equation for Coulombic systems. By rearranging the kinetic and potential energy terms in the temporal propagator of the finite difference equations, one can find a propagation algorithm for three dimensions that looks much like the Crank-Nicholson and alternating direction implicit methods for one- and two-space-dimensional partial differential equations. The authors report investigations of this novel implicit split operator procedure. The results look promising for a purely numerical approach to certain electron quantum mechanical problems. A charge exchange calculation is presented as an example of the power of the method.

  7. Coulombic contribution and fat center vortex model

    SciTech Connect

    Rafibakhsh, Shahnoosh; Deldar, Sedigheh

    2007-02-27

    The fat (thick) center vortex model is one of the phenomenological models which is fairly successful to interpret the linear potential between static sources. However, the Coulombic part of the potential has not been investigated by the model yet. In an attempt to get the Coulombic contribution and to remove the concavity of the potentials, we are studying different vortex profiles and vortex sizes.

  8. Stereoscopic Investigations of 3D Coulomb Balls

    SciTech Connect

    Kaeding, Sebastian; Melzer, Andre; Arp, Oliver; Block, Dietmar; Piel, Alexander

    2005-10-31

    In dusty plasmas particles are arranged due to the influence of external forces and the Coulomb interaction. Recently Arp et al. were able to generate 3D spherical dust clouds, so-called Coulomb balls. Here, we present measurements that reveal the full 3D particle trajectories from stereoscopic imaging.

  9. PREFACE: Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Fortov, Vladimir E.; Golden, Kenneth I.; Norman, Genri E.

    2006-04-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS) which was held during the week of 20 24 June 2005 in Moscow, Russia. The Moscow conference was the tenth in a series of conferences. The previous conferences were organized as follows. 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (organized by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (organized by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, NY, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) After 1995 the name of the series was changed from `Strongly Coupled Plasmas' to the present name in order to extend the topics of the conferences. The planned frequency for the future is once every three years. The purpose of these conferences is to provide an international forum for the presentation and discussion of research accomplishments and ideas relating to a variety of plasma liquid and condensed matter systems, dominated by strong Coulomb interactions between their constituents. Strongly coupled Coulomb systems encompass diverse many-body systems and physical conditions. Each meeting has seen an evolution of topics and emphasis as new discoveries and new methods appear. This year, sessions were organized for invited presentations and posters on dense plasmas and warm matter, astrophysics and dense hydrogen, non-neutral and ultracold plasmas, dusty plasmas, condensed matter 2D and layered charged-particle systems, Coulomb liquids, and statistical theory of SCCS. Within

  10. Plane Wave and Coulomb Asymptotics

    NASA Astrophysics Data System (ADS)

    Mulligan, P. G.; Crothers, D. S. F.

    2004-01-01

    A simple plane wave solution of the Schrödinger Helmholtz equation is a quantum eigenfunction obeying both energy and linear momentum correspondence principles. Inclusion of the outgoing wave with scattering amplitude f obeys unitarity and the optical theorem. By closely considering the standard asymptotic development of the plane wave, we show that there is a problem with angular momentum when we consider forward scattering at the point of closest approach and at large impact parameter given semiclassically by (l + 1/2)/k where l is the azimuthal quantum number and may be large (J Leech et al, Phys. Rev. Lett. 88 257901 (2002)). The problem is resolved via non-uniform, non-standard analysis involving the Heaviside step function, unifying classical, semiclassical and quantum mechanics, and the treatment is extended to the case of pure Coulomb scattering.

  11. Coulomb blockade with neutral modes.

    PubMed

    Kamenev, Alex; Gefen, Yuval

    2015-04-17

    We study transport through a quantum dot in the fractional quantum Hall regime with filling factors ν=2/3 and ν=5/2, weakly coupled to the leads. We account for both injection of electrons to or from the leads, and quasiparticle rearrangement processes between the edge and the bulk of the quantum dot. The presence of neutral modes introduces topological constraints that modify qualitatively the features of the Coulomb blockade (CB). The periodicity of CB peak spacings doubles and the ratio of spacing between adjacent peaks approaches (in the low temperature and large dot limit) a universal value: 2∶1 for ν=2/3 and 3∶1 for ν=5/2. The corresponding CB diamonds alternate their width in the direction of the bias voltage and allow for the determination of the neutral mode velocity, and of the topological numbers associated with it. PMID:25933323

  12. Nucleases Encoded by Integrated Elements CJIE2 and CJIE4 Inhibit Natural Transformation of Campylobacter jejuni

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The species Campylobacter jejuni displays huge genetic diversity, and is naturally competent for DNA uptake. Nevertheless, not every strain is able to acquire foreign DNA since nonnaturally transformable strains do exist. Previously we showed that many nonnaturally transformable C. jejuni strains ex...

  13. The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.

    ERIC Educational Resources Information Center

    Francisco, E.; And Others

    1988-01-01

    Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)

  14. An inversion formula for the spherical transform in S2 for a special family of circles of integration

    NASA Astrophysics Data System (ADS)

    Salman, Yehonatan

    2016-03-01

    In this article, an inversion formula is obtained for the spherical transform which integrates functions, defined on the unit sphere S2, on circles. The inversion formula is for the case where the circles of integration are obtained by intersections of S2 with hyperplanes passing through a common point overline{a} strictly inside S2. In particular, this yields inversion formulas for two well-known special cases. The first inversion formula is for the special case where the family of circles of integration consists of great circles; this formula is obtained by taking overline{a} = 0. The second inversion formula is for the special case where the circles of integration pass through a common point p on S2; this formula is obtained by taking the limit overline{a}→ p.

  15. Dynamical Coulomb blockade of tunnel junctions driven by alternating voltages

    NASA Astrophysics Data System (ADS)

    Grabert, Hermann

    2015-12-01

    The theory of the dynamical Coulomb blockade is extended to tunneling elements driven by a time-dependent voltage. It is shown that, for standard setups where an external voltage is applied to a tunnel junction via an impedance, time-dependent driving entails an excitation of the modes of the electromagnetic environment by the applied voltage. Previous approaches for ac driven circuits need to be extended to account for the driven bath modes. A unitary transformation involving also the variables of the electromagnetic environment is introduced which allows us to split off the time dependence from the Hamiltonian in the absence of tunneling. This greatly simplifies perturbation-theoretical calculations based on treating the tunneling Hamiltonian as a perturbation. In particular, the average current flowing in the leads of the tunnel junction is studied. Explicit results are given for the case of an applied voltage with a constant dc part and a sinusoidal ac part. The connection with standard dynamical Coulomb blockade theory for constant applied voltage is established. It is shown that an alternating voltage source reveals significant additional effects caused by the electromagnetic environment. The hallmark of the dynamical Coulomb blockade in ac driven devices is a suppression of higher harmonics of the current by the electromagnetic environment. The theory presented basically applies to all tunneling devices driven by alternating voltages.

  16. Gauge equivalence in QCD: The Weyl and Coulomb gauges

    NASA Astrophysics Data System (ADS)

    Haller, Kurt; Ren, Hai-Cang

    2003-10-01

    The Weyl-gauge (Aa0=0) QCD Hamiltonian is unitarily transformed to a representation in which it is expressed entirely in terms of gauge-invariant quark and gluon fields. In a subspace of gauge-invariant states we have constructed that implement the non-Abelian Gauss’s law, this unitarily transformed Weyl-gauge Hamiltonian can be further transformed and, under appropriate circumstances, can be identified with the QCD Hamiltonian in the Coulomb gauge. We demonstrate an isomorphism that materially facilitates the application of this Hamiltonian to a variety of physical processes, including the evaluation of S-matrix elements. This isomorphism relates the gauge-invariant representation of the Hamiltonian and the required set of gauge-invariant states to a Hamiltonian of the same functional form but dependent on ordinary unconstrained Weyl-gauge fields operating within a space of “standard” perturbative states. The fact that the gauge-invariant chromoelectric field is not Hermitian has important implications for the functional form of the Hamiltonian finally obtained. When this non-Hermiticity is taken into account, the “extra” vertices in the Christ-Lee’ Coulomb-gauge Hamiltonian are natural outgrowths of the formalism. When this non-Hermiticity is neglected, the Hamiltonian used in the earlier work of Gribov and others results.

  17. DNA Integrity and Shock Wave Transformation Efficiency of Bacteria and Fungi

    NASA Astrophysics Data System (ADS)

    Loske, Achim M.; Campos-Guillén, Juan; Fernández, Francisco; Pastrana, Xóchitl; Magaña-Ortíz, Denis; Coconi-Linares, Nancy; Ortíz-Vázquez, Elizabeth; Gómez-Lim, Miguel

    Delivery of DNA into bacteria and fungi is essential in medicine and biotechnology to produce metabolites, enzymes, antibiotics and proteins. So far, protocols to genetically transform bacteria and fungi are inefficient and have low reproducibility.

  18. Exploring the separability of the three-body Coulomb problem in hyperspherical elliptic coordinates

    NASA Astrophysics Data System (ADS)

    Tolstikhin, Oleg I.; Matsuzawa, Michio

    2001-06-01

    An approximate symmetry of the three-body Coulomb problem which reveals itself via approximate separability of the hyperspherical adiabatic (HSA) eigenvalue problem in hyperspherical elliptic (HSE) coordinates (η,ξ) and thus is intimately related to the HSA approximation is discussed. The additional integral of motion responsible for this separability is specific to the Coulomb interaction and generalizes the Laplace-Runge-Lentz vector known from the two-body Coulomb problem and the integral of separation constant of the two-center Coulomb problem. In the zeroth approximation, this symmetry leads to a completely separable representation of the three-body wave function, where each state is labeled by a pair of HSE quantum numbers (nη,nξ) that generalize the spheroidal quantum numbers for diatomic molecules, on the one hand, and the Herrick-Lin quantum numbers for two-electron atoms, on the other. This approximation is illustrated by calculations for a number of three-body Coulomb systems for states with zero total angular momentum. Taking into account the nonadiabatic couplings as well as the nonseparable part of the Coulomb potential by mixing a few separable states permits one to obtain accurate results for systems with arbitrary masses and charges of particles and for a wide spectrum below the three-body breakup threshold.

  19. The algebra of the quantum nondegenerate three-dimensional Kepler-Coulomb potential

    SciTech Connect

    Tanoudis, Y.; Daskaloyannis, C.

    2011-07-15

    The classical generalized Kepler-Coulomb potential, introduced by Verrier and Evans, corresponds to a quantum superintegrable system, with quadratic and quartic integrals of motion. In this paper we show that the algebra of the integrals is a quadratic ternary algebra, i.e a quadratic extension of a Lie triple system.

  20. Crystallization in two-component Coulomb systems.

    PubMed

    Bonitz, M; Filinov, V S; Fortov, V E; Levashov, P R; Fehske, H

    2005-12-01

    The analysis of Coulomb crystallization is extended from one-component to two-component plasmas. Critical parameters for the existence of Coulomb crystals are derived for both classical and quantum crystals. In the latter case, a critical mass ratio of the two charged components is found, which is of the order of 80. Thus, holes in semiconductors with sufficiently flat valence bands are predicted to spontaneously order into a regular lattice. Such hole crystals are intimately related to ion Coulomb crystals in white dwarf and neutron stars as well as to ion crystals produced in the laboratory. A unified phase diagram of two-component Coulomb crystals is presented and is verified by first-principles computer simulations. PMID:16384315

  1. Coulomb Glass: a Mean Field Study

    NASA Astrophysics Data System (ADS)

    Mandra, Salvatore; Palassini, Matteo

    2012-02-01

    We study the Coulomb glass model of disordered localized electrons with long-range Coulomb interaction, which describes systems such as disordered insulators, granular metals, amorphous semiconductors, or doped crystalline semiconductors. Long ago Efros and Shklovskii showed that the long-range repulsion induces a soft Coulomb gap in the single particle density of states at low temperatures. Recent works suggested that this gap is associated to a transition to a glass phase, similar to the Almeida-Thouless transition in spin glasses. In this work, we use a mean field approach to characterize several physical properties of the Coulomb glass. In particular, following a seminal work of Bray and Moore, we show that the Edward-Anderson parameter qEA and the spin glass susceptibility χSG are directly related to spectrum distribution of the Hessian matrix around free energy minima. Using this result, we show that no glass transition is associated to the gap formation.

  2. Integrated Deployment Model: A Comprehensive Approach to Transforming the Energy Economy

    SciTech Connect

    Werner, M.

    2010-11-01

    This paper describes the Integrated Deployment model to accelerate market adoption of alternative energy solutions to power homes, businesses, and vehicles through a comprehensive and aggressive approach.

  3. Coulomb crystal mass spectrometry in a digital ion trap

    NASA Astrophysics Data System (ADS)

    Deb, Nabanita; Pollum, Laura L.; Smith, Alexander D.; Keller, Matthias; Rennick, Christopher J.; Heazlewood, Brianna R.; Softley, Timothy P.

    2015-03-01

    We present a mass spectrometric technique for identifying the masses and relative abundances of Coulomb-crystallized ions held in a linear Paul trap. A digital radio-frequency wave form is employed to generate the trapping potential, as this can be cleanly switched off, and static dipolar fields are subsequently applied to the trap electrodes for ion ejection. Close to 100% detection efficiency is demonstrated for Ca+ and CaF+ ions from bicomponent Ca+-CaF+ Coulomb crystals prepared by the reaction of Ca+ with CH3F . A quantitative linear relationship is observed between ion number and the corresponding integrated time-of-flight (TOF) peak, independent of the ionic species. The technique is applicable to a diverse range of multicomponent Coulomb crystals—demonstrated here for Ca+-NH 3+ -NH 4+ and Ca+-CaOH +-CaOD + crystals—and will facilitate the measurement of ion-molecule reaction rates and branching ratios in complicated reaction systems.

  4. Coulomb Distortion in the Inelastic Regime

    SciTech Connect

    Patricia Solvignon, Dave Gaskell, John Arrington

    2009-09-01

    The Coulomb distortion effects have been for a long time neglected in deep inelastic scattering for the good reason that the incident energies were very high. But for energies in the range of earlier data from SLAC or at JLab, the Coulomb distortion could have the potential consequence of affecting the A-dependence of the EMC effect and of the longitudinal to transverse virtual photon absorption cross section ratio $R(x,Q^2)$.

  5. Modelling Coulomb Collisions in Anisotropic Plasmas

    NASA Astrophysics Data System (ADS)

    Hellinger, P.; Travnicek, P. M.

    2009-12-01

    Collisional transport in anisotropic plasmas is investigated comparing the theoretical transport coefficients (Hellinger and Travnicek, 2009) for anisotropic particles with the results of the corresponding Langevin equation, obtained as a generalization of Manheimer et al. (1997). References: Hellinger, P., and P. M. Travnicek (2009), On Coulomb collisions in bi-Maxwellian plasmas, Phys. Plasmas, 16, 054501. Manheimer, W. M., M. Lampe and G. Joyce (1997), Langevin representation of Coulomb collisions in PIC simulations, J. Comput. Phys., 138, 563-584.

  6. Transformative Experience: An Integrative Construct in the Spirit of Deweyan Pragmatism

    ERIC Educational Resources Information Center

    Pugh, Kevin J.

    2011-01-01

    A sentiment held by Dewey and shared by other educators is that learning should enrich and expand everyday experience. However, this goal has not been a focus of research. In this article, I propose "transformative experience" as a construct capable of reflecting this goal and functioning as an empirical research construct. I discuss the…

  7. Cancer cell stiffness: integrated roles of three-dimensional matrix stiffness and transforming potential.

    PubMed

    Baker, Erin L; Lu, Jing; Yu, Dihua; Bonnecaze, Roger T; Zaman, Muhammad H

    2010-10-01

    While significant advances have been made toward revealing the molecular mechanisms that influence breast cancer progression, much less is known about the associated cellular mechanical properties. To this end, we use particle-tracking microrheology to investigate the interplay among intracellular mechanics, three-dimensional matrix stiffness, and transforming potential in a mammary epithelial cell (MEC) cancer progression series. We use a well-characterized model system where human-derived MCF10A MECs overexpress either ErbB2, 14-3-3ζ, or both ErbB2 and 14-3-3ζ, with empty vector as a control. Our results show that MECs possessing ErbB2 transforming potential stiffen in response to elevated matrix stiffness, whereas non-transformed MECs or those overexpressing only 14-3-3ζ do no exhibit this response. We further observe that overexpression of ErbB2 alone is associated with the highest degree of intracellular sensitivity to matrix stiffness, and that the effect of transforming potential on intracellular stiffness is matrix-stiffness-dependent. Moreover, our intracellular stiffness measurements parallel cell migration behavior that has been previously reported for these MEC sublines. Given the current knowledge base of breast cancer mechanobiology, these findings suggest that there may be a positive relationship among intracellular stiffness sensitivity, cell motility, and perturbed mechanotransduction in breast cancer. PMID:20923638

  8. Transforming Pedagogies: Integrating 21st Century Skills and Web 2.0 Technology

    ERIC Educational Resources Information Center

    Tucker, Shelia Y.

    2014-01-01

    According to (P21), Partnership for 21st Century Skills (n.d.), unless the gap is bridged between how students learn and how they live, today's education system will face irrelevance. The way people work and live has been transformed by demographic, economic, political, technological, and informational forces. Schools must adapt to these…

  9. Challenging Core Assumptions: Integrating Transformative Leadership Models into Campus-Wide Implementation Activities.

    ERIC Educational Resources Information Center

    Cramer, Sharon F.

    2003-01-01

    Examines three cycles of activities during the multi-year implementation of new student services software at a Masters I public comprehensive college with an enrollment of 12,000. Uses the theoretical framework of transformative leadership. Interpretations and recommendations address organizational issues that can be generalized beyond the…

  10. A DNase encoded by integrated element CJIE1 inhibits natural transformation of Campylobacter jejuni

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The species Campylobacter jejuni (C. jejuni) is considered naturally competent for DNA uptake and displays strong genetic diversity. Yet, non-transformable strains and several relatively stable clonal lineages exist. In the present study, the molecular mechanism responsible for the non-transformabil...

  11. Transforming University Practice through ICT--Integrated Perspectives on Organizational, Technological, and Pedagogical Change

    ERIC Educational Resources Information Center

    Dirckinck-Holmfeld, Lone; Lorentsen, Annette

    2003-01-01

    The article focuses on the use of information and communication technology (ICT) for strengthening and transforming university practice in line with the social and technological conditions of the new ideas for "interactive" universities. The purpose is to use ICT as a change-agent in order to establish new practices--new pedagogical methods, new…

  12. An integrated computer model with applications for austenite-to-ferrite transformation during hot deformation of Nb-microalloyed steels

    NASA Astrophysics Data System (ADS)

    Majta, Janusz; Pietrzyk, Maciej; Zurek, Anna K.; Cola, Mark; Hochanadel, Pat

    2002-05-01

    This work presents an austenite decomposition model, based on the thermodynamics of the system and diffusion-controlled nucleation theory, to predict the evolution of microstructure during hot working of niobium-microalloyed steels. The differences in microstructural development of hotdeformed microalloyed steel in the single-phase austenite and two-phase (austenite + ferrite) regions have been effectively described using an integrated computer modeling process. The complete model presented here takes into account the kinetics of recrystallization, recrystallized austenite grain size, precipitation, phase transformation, and the resulting ferrite structure. After considering existing austenite decomposition models, we decided that the method adopted in the present work relies on isothermal transformation kinetics and the principle-of-additivity rule. The thermomechanical part of the modeling process was carried out using the finite-element method. Experimental results at different temperatures, strain rates, and strain levels were obtained using a Gleeble thermomechanical simulator. A comparison of results of the model with experiments shows good agreement.

  13. Interferometry based multispectral photon-limited 2D and 3D integral image encryption employing the Hartley transform.

    PubMed

    Muniraj, Inbarasan; Guo, Changliang; Lee, Byung-Geun; Sheridan, John T

    2015-06-15

    We present a method of securing multispectral 3D photon-counted integral imaging (PCII) using classical Hartley Transform (HT) based encryption by employing optical interferometry. This method has the simultaneous advantages of minimizing complexity by eliminating the need for holography recording and addresses the phase sensitivity problem encountered when using digital cameras. These together with single-channel multispectral 3D data compactness, the inherent properties of the classical photon counting detection model, i.e. sparse sensing and the capability for nonlinear transformation, permits better authentication of the retrieved 3D scene at various depth cues. Furthermore, the proposed technique works for both spatially and temporally incoherent illumination. To validate the proposed technique simulations were carried out for both the 2D and 3D cases. Experimental data is processed and the results support the feasibility of the encryption method. PMID:26193568

  14. Gravity duals for the Coulomb branch of marginally deformed Script N = 4 Yang-Mills

    NASA Astrophysics Data System (ADS)

    Hernández, Rafael; Sfetsos, Konstadinos; Zoakos, Dimitrios

    2006-03-01

    Supergravity backgrounds dual to a class of exactly marginal deformations of Script N = 4 supersymmetric Yang-Mills can be constructed through an SL(2,Bbb R) sequence of T-dualities and coordinate shifts. We apply this transformation to multicenter solutions and derive supergravity backgrounds describing the Coulomb branch of Script N = 1 theories at strong 't Hooft coupling as marginal deformations of Script N = 4 Yang-Mills. For concreteness we concentrate to cases with an SO(4) × SO(2) symmetry preserved by continuous distributions of D3-branes on a disc and on a three-dimensional spherical shell. We compute the expectation value of the Wilson loop operator and confirm the Coulombic behaviour of the heavy quark-antiquark potential in the conformal case. When the vev is turned on we find situations where a complete screening of the potential arises, as well as a confining regime where a linear or a logarithmic potential prevails depending on the ratio of the quark-antiquark separation to the typical vev scale. The spectra of massless excitations on these backgrounds are analyzed by turning the associated differential equations into Schrödinger problems. We find explicit solutions taking into account the entire tower of states related to the reduction of type-IIB supergravity to five dimensions, and hence we go beyond the s-wave approximation that has been considered before for the undeformed case. Arbitrary values of the deformation parameter give rise to the Heun differential equation and the related Inozemtsev integrable system, via a non-standard trigonometric limit as we explicitly demonstrate.

  15. Integrable maps from Galois differential algebras, Borel transforms and number sequences

    NASA Astrophysics Data System (ADS)

    Tempesta, Piergiulio

    A new class of integrable maps, obtained as lattice versions of polynomial dynamical systems is introduced. These systems are obtained by means of a discretization procedure that preserves several analytic and algebraic properties of a given differential equation, in particular symmetries and integrability (see Tempesta, 2010 [40]). Our approach is based on the properties of a suitable Galois differential algebra, that we shall call a Rota algebra. A formulation of the procedure in terms of category theory is proposed. In order to render the lattice dynamics confined, a Borel regularization is also adopted. As a byproduct of the theory, a connection between number sequences and integrability is discussed.

  16. Rolled-up transformer structure for a radiofrequency integrated circuit (RFIC)

    DOEpatents

    Li, Xiuling; Huang, Wen

    2016-05-03

    A rolled-up transformer structure comprises a multilayer sheet having a rolled configuration comprising multiple turns about a longitudinal axis. The multilayer sheet comprises more than one conductive pattern layer on a strain-relieved layer, including a first conductive film and a second conductive film separated from the first conductive film in a thickness direction. The first conductive film comprises an even number of primary conductive strips, where each primary conductive strip has a length extending in the rolling direction, and the second conductive film comprises an even number of secondary conductive strips, where each secondary conductive strip has a length extending in the rolling direction. In the rolled configuration, turns of the primary conductive strips and turns of the secondary conductive strips wrap around the longitudinal axis. The primary conductive strips serve as a primary winding and the secondary conductive strips serve as a secondary winding of the rolled-up transformer structure.

  17. Rolled-up transformer structure for a radiofrequency integrated circuit (RFIC)

    SciTech Connect

    Li, Xiuling; Huang, Wen

    2015-01-27

    A rolled-up transformer structure comprises a multilayer sheet having a rolled configuration comprising multiple turns about a longitudinal axis. The multilayer sheet comprises more than one conductive pattern layer on a strain-relieved layer, including a first conductive film and a second conductive film separated from the first conductive film in a thickness direction. The first conductive film comprises an even number of primary conductive strips, where each primary conductive strip has a length extending in the rolling direction, and the second conductive film comprises an even number of secondary conductive strips, where each secondary conductive strip has a length extending in the rolling direction. In the rolled configuration, turns of the primary conductive strips and turns of the secondary conductive strips wrap around the longitudinal axis. The primary conductive strips serve as a primary winding and the secondary conductive strips serve as a secondary winding of the rolled-up transformer structure.

  18. Blue genes: An integrative laboratory to differentiate genetic transformation from gene mutation for underclassmen.

    PubMed

    Militello, Kevin T; Chang, Ming-Mei; Simon, Robert D; Lazatin, Justine C

    2016-01-01

    The ability of students to understand the relationship between genotype and phenotype, and the mechanisms by which genotypes and phenotypes can change is essential for students studying genetics. To this end, we have developed a four-week laboratory called Blue Genes, which is designed to help novice students discriminate between two mechanisms by which the genetic material can be altered: genetic transformation and gene mutation. In the first week of the laboratory, students incubate a plasmid DNA with calcium chloride-treated Escherichia coli JM109 cells and observe a phenotype change from ampicillin sensitive to ampicillin resistant and from white color to blue color on plates containing 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) and isopropyl β-D-thiogalactopyranoside (IPTG). Over the course of the next three weeks, students use a battery of approaches including plasmid DNA isolation experiments, restriction maps, and PCR to differentiate between mutation and transformation. The students ultimately come to the conclusion that the changes in phenotypes are due to genetic transformation and not mutation based on the evidence generated over the four-week period. Pre-laboratory tests and post-laboratory tests indicate that this set of exercises is successful in helping students differentiate between transformation and mutation. The laboratory is designed for underclassmen and is a good prerequisite for an apprentice-based research opportunity, although it is not designed as a class based research experience. Potential modifications and future directions of the laboratory based upon student experiences and assessment are presented. PMID:26525488

  19. A Monte Carlo study of the generalized Coulomb Milne problem

    NASA Astrophysics Data System (ADS)

    Barghouthi, I. A.; Barakat, A. R.

    2005-11-01

    Because of its relevance to space plasma problems (such as the terrestrial polar wind), we investigated the diffusion of a minor ion species through a non-uniform background major ion species. A Fokker Planck expression was used to represent the Coulomb collisions between the minor and the background ions. A change of variables was implemented in order to transform the problem into a simpler form where the background medium is uniform. This transformed problem described minor ions diffusing through a background of ions with constant density in the semi-infinite region z˜⩾0 and zero density in the region z˜<0. This problem was termed the generalized Coulomb Milne problem and was addressed by a Monte Carlo simulation. Three different minor-to-background mass ratios (γ) were considered, namely γ=16, 1, and 116, which were relevant to H and O ions, the two most dominant ions in the terrestrial ionosphere. The minor ion velocity distribution (f) and the velocity moments (density (n); drift velocity (u), parallel (T) and perpendicular (T) temperatures; and parallel (q˜s∥) and perpendicular (q˜s⊥) heat fluxes) were computed. For the cases when the minor species mass was comparable to, or larger than the background species mass (γ=16,1), the distribution was close to Maxwellian at low altitudes due to Coulomb collisions, gradually formed a weak upward tail in the transition region, and eventually assumed a half-Maxwellian shape at the collisionless region. This was reflected in the enhancement of the flow and random energies, and the energy fluxes for these cases. Deep into the collision-dominated region, n was found to be linearly dependent on the normalized distance z˜ with a gradient (m=dn˜/dz˜). As γ decreased from 16 to 1 to 116, m decreased from 2.0 to 1.7 to 0.75, respectively. For the case of a lighter minor ion species drifting through a heavier background ion species (e.g. γ=116), the ion outflow exhibited some interesting qualitatively

  20. The distinguishable cluster approach from a screened Coulomb formalism.

    PubMed

    Kats, Daniel

    2016-01-28

    The distinguishable cluster doubles equations have been derived starting from an effective screened Coulomb formalism and a particle-hole symmetric formulation of the Fock matrix. A perturbative triples correction to the distinguishable cluster with singles and doubles (DCSD) has been introduced employing the screened integrals. It is shown that the resulting DCSD(T) method is more accurate than DCSD for reaction energies and is less sensitive to the static correlation than coupled cluster with singles and doubles with a perturbative triples correction. PMID:26827197

  1. Application of Transformational Leadership Principles in the Development and Integration of Palliative Care Within an Advanced Heart Failure Program.

    PubMed

    George, Susan; Leasure, A Renee

    2016-01-01

    Heart failure (HF) is a major health problem in United States, and it has reached epidemic proportions. Heart failure is associated with significant morbidity, mortality, and cost. Although the prognosis of HF is worse than many forms of cancer, many patients, families, and clinicians are unaware of the dire prognosis. As the disease progress to advanced HF, patients are faced with many challenges, such as poor quality of life due to worsening symptoms and frequent hospitalizations. Heart failure management adds significant financial burden to the health care system. Palliative care can be integrated into HF care to improve quality of life and symptom management and to address physical, spiritual, and psychosocial needs of patients and families. Palliative care can be used concurrently with or independent of curative or life-prolonging HF therapies. Transformational leadership principles were used to guide the development of a plan to enhance integration of palliative care within traditional advanced HF care. PMID:26836596

  2. Expression and genomic integration of transgenes after Agrobacterium-mediated transformation of mature barley embryos.

    PubMed

    Uçarlı, C; Tufan, F; Gürel, F

    2015-01-01

    Mature embryos in tissue cultures are advantageous because of their abundance and rapid germination, which reduces genomic instability problems. In this study, 2-day-old isolated mature barley embryos were infected with 2 Agrobacterium hypervirulent strains (AGL1 and EHA105), followed by a 3-day period of co-cultivation in the presence of L-cystein amino acid. Chimeric expression of the b-glucuronidase gene (gusA) directed by a viral promoter of strawberry vein banding virus was observed in coleoptile epidermal cells and seminal roots in 5-day-old germinated seedlings. In addition to varying infectivity patterns in different strains, there was a higher ratio of transient b-glucuronidase expression in developing coleoptiles than in embryonic roots, indicating the high competency of shoot apical meristem cells in the mature embryo. A total of 548 explants were transformed and 156 plants developed to maturity on G418 media after 18-25 days. We detected transgenes in 74% of the screened plant leaves by polymerase chain reaction, and 49% of these expressed neomycin phosphotransferase II gene following AGL1 transformation. Ten randomly selected T0 transformants were analyzed using thermal asymmetric interlaced polymerase chain reaction and 24 fragments ranged between 200-600 base pairs were sequenced. Three of the sequences flanked with transferred-DNA showed high similarity to coding regions of the barley genome, including alpha tubulin5, homeobox 1, and mitochondrial 16S genes. We observed 70-200-base pair filler sequences only in the coding regions of barley in this study. PMID:25730049

  3. Multicenter molecular integrals for Slater orbitals of higher principal quantum numbers

    NASA Technical Reports Server (NTRS)

    Tai, H.

    1989-01-01

    As was shown earlier by Tai (1979), by using the Fourier-transform technique and properly coupling a pair of two-center exchange integrals, the multicenter molecular integrals can be cast into a simple expression upon which numerical procedures can be directly applied. In this paper, the procedure of Tai is extended to integrals involving orbitals with arbitrarily higher principal quantum number. The derivation is outlined, and the explicit expressions are presented for a three-center nuclear attraction integral and a four-center two-electron Coulomb repulsion integral of arbitrary higher states.

  4. Revenue Forecasting to Integrate CCC Planning and Resource Allocation for Transformative Leadership

    ERIC Educational Resources Information Center

    Hovey, Ann

    2012-01-01

    In recent years the majority of California community colleges evaluated for re-accreditation received sanctions requiring documented improvement in the integration of college planning and budgeting processes. This study explores the challenges colleges face and the best practices utilized by successful colleges in implementing integrated…

  5. 1/f Noise in a Coulomb Glass.

    NASA Astrophysics Data System (ADS)

    Yu, Clare C.; Shtengel, Kirill

    2002-03-01

    Low frequency 1/f noise is found in Coulomb glasses, among other systems with slow relaxation. It has been recently studied in detail in Si:B in the experimental work of Massey and Lee [1]. They concluded that their findings were inconsistent with the single-particle mechanisms proposed earlier. We show that the observed noise can be produced by charge fluctuations due to electrons hopping between isolated sites and a percolating network at low temperatures [2]. Coulomb interactions are included through the Coulomb gap in the density of states. The low frequency noise spectrum goes as ω^-α with α slightly larger than 1. This result, together with the temperature dependence of α and the noise amplitude are in good agreement with the experiments of Massey and Lee. [1] J. G. Massey and Mark Lee, Phys. Rev. Lett. 79, 3986 (1997). [2] Kirill Shtengel and Clare C. Yu (2001), cond-mat/0111302.

  6. A new algorithm for integrated image quality measurement based on wavelet transform and human visual system

    NASA Astrophysics Data System (ADS)

    Wang, Haihui

    2006-01-01

    An essential determinant of the value of digital images is their quality. Over the past years, there have been many attempts to develop models or metrics for image quality that incorporate elements of human visual sensitivity. However, there is no current standard and objective definition of spectral image quality. This paper proposes a reliable automatic method for objective image quality measurement by wavelet transform and Human visual system. This way the proposed measure differentiates between the random and signal-dependant distortion, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation. The technique provides a means to relate the quality of an image to the interpretation and quantification throughout the frequency range, in which the noise level is estimated for quality evaluation. The experimental results of using this method for image quality measurement exhibit good correlation to subjective visual quality assessments.

  7. Extract transformation loading from OLTP to OLAP data using pentaho data integration

    NASA Astrophysics Data System (ADS)

    Salaki, R. J.; Waworuntu, J.; Tangkawarow, I. R. H. T.

    2016-04-01

    The design of the data warehouse in this case is expected to solve the problem of evaluation of learning results as well as the relevance of the information received to support decision-making by the leader. Data warehouse design is very important, which is designed to utilize the existing resources of information. GPA (Grade Point Average) data warehouse can be used for the process of evaluation, decision making and even further planning of the study program of PTIK. The diversity of data sources in the course PTIK make decisionmaking and evaluation process becomes not easier. Pentaho Data Integration is used to integrate data in PTIK easy. CPI data warehouse design with multidimensional database modeling approach using the dimension tables and fact tables.

  8. Nonlocal formulation of spin Coulomb drag

    NASA Astrophysics Data System (ADS)

    D'Amico, I.; Ullrich, C. A.

    2013-10-01

    The spin Coulomb drag (SCD) effect occurs in materials and devices where charged carriers with different spins exchange momentum via Coulomb scattering. This causes frictional forces between spin-dependent currents that lead to intrinsic dissipation, which may limit spintronics applications. A nonlocal formulation of SCD is developed which is valid for strongly inhomogeneous systems such as nanoscale spintronics devices. This nonlocal formulation of SCD is successfully applied to linewidths of intersubband spin plasmons in semiconductor quantum wells, where experiments have shown that the local approximation fails.

  9. Coulomb balls in Experiment and Simulation

    SciTech Connect

    Block, D.; Arp, O.; Piel, A.; Melzer, A.

    2005-10-31

    Recently, it was shown that it is possible to confine spherical dust clouds in a plasma. It was found that these dust clouds have a crystalline structure which differs notably from the well known fcc, bcc and hcp order in extended crystalline systems. The experiments show that the particles arrange in nested shells with hexagonal order on individual shells. The high transparency and the rather slow time scales of Coulomb balls allow to observe individual particles with video microscopy techniques and therefore to determine the structural properties of Coulomb balls with high accuracy. This contribution presents a comparison of experimental results and MD-Simulations.

  10. Observation of ionic Coulomb blockade in nanopores

    NASA Astrophysics Data System (ADS)

    Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; di Ventra, Massimiliano; Radenovic, Aleksandra

    2016-08-01

    Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels.

  11. Coulomb force as an entropic force

    SciTech Connect

    Wang Tower

    2010-05-15

    Motivated by Verlinde's theory of entropic gravity, we give a tentative explanation to the Coulomb's law with an entropic force. When trying to do this, we find the equipartition rule should be extended to charges and the concept of temperature should be reinterpreted. If one accepts the holographic principle as well as our generalizations and reinterpretations, then Coulomb's law, the Poisson equation, and the Maxwell equations can be derived smoothly. Our attempt can be regarded as a new way to unify the electromagnetic force with gravity, from the entropic origin. Possibly some of our postulates are related to the D-brane picture of black hole thermodynamics.

  12. Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method

    NASA Astrophysics Data System (ADS)

    Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko

    2010-06-01

    We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.

  13. Triple transformation

    NASA Astrophysics Data System (ADS)

    Khan, Farrukh I.; Schinn, Dustin S.

    2013-08-01

    A new business plan that enables policy transformation and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.

  14. Coulomb string tension, asymptotic string tension, and the gluon chain

    SciTech Connect

    Greensite, Jeff; Szczepaniak, Adam P.

    2015-02-01

    We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.

  15. InTeGrate: Transforming the Teaching of Geoscience and Sustainability

    NASA Astrophysics Data System (ADS)

    Blockstein, D.; Manduca, C. A.; Bralower, T. J.; Castendyk, D.; Egger, A. E.; Gosselin, D. C.; Iverson, E. A.; Matson, P. A.; MacGregor, J.; Mcconnell, D. A.; Mogk, D. W.; Nevle, R. J.; Oches, E. A.; Steer, D. N.; Wiese, K.

    2012-12-01

    InTeGrate is an NSF-funded community project to improve geoscience literacy and build a workforce that can apply geoscience principles to address societal issues. Three workshops offered this year by InTeGrate and its partner, On the Cutting Edge, addressed strategies for bringing together geoscience and sustainability within geoscience courses and programs, in interdisciplinary courses and programs, and in courses and programs in other disciplines or schools including arts and humanities, health science, and business. Participants in all workshops described the power of teaching geoscience in the context of sustainability and the utility of this approach in engaging students with geoscience, including student populations not traditionally represented in the sciences. Faculty involved in both courses and programs seek to teach important skills including the ability to think about systems and to make connections between local observations and challenges and global phenomena and issues. Better articulation of these skills, including learning outcomes and assessments, as well as documenting the relationship between these skills and employment opportunities were identified as important areas for further work. To support widespread integration of geoscience and sustainability concepts, these workshops initiated collections describing current teaching activities, courses, and programs. InTeGrate will continue to build these collections in collaboration with On the Cutting Edge and Building Strong Geoscience Departments, and through open contributions by individual faculty and programs. In addition, InTeGrate began developing new teaching modules and courses. Materials for use in introductory geoscience and environmental science/studies courses, distance learning courses, and courses for education majors are being developed and tested by teams of faculty drawn from at least three institutions, including several members from two-year colleges. An assessment team is

  16. Transformation of Care: Integrating the Registered Nurse Care Coordinator into the Patient-Centered Medical Home.

    PubMed

    Biernacki, Pamela J; Champagne, Mary T; Peng, Shane; Maizel, David R; Turner, Barbara S

    2015-10-01

    The purpose of this quality improvement project was to implement and evaluate a care delivery model integrating the registered nurse care coordinator (RNCC) into a family practice that is certified as a patient-centered medical home (PCMH) by the National Committee for Quality Assurance. The initial target population was the 937 patients with diabetes in the family practice. A pre-post design was used to assess changes in patients' diabetic quality indicators after integrating the role of RNCC using existing staff. This 6-month project compared the following diabetic quality indicators: blood pressure < 140/90 mm Hg, hemoglobin A1c ≤ 7, low-density lipoprotein cholesterol < 100 mg/dL, documentation of smoking cessation counseling, and aspirin prescription if existing vascular disease. Yearly documentation of microalbuminurea level, and filament foot and retinal examination was assessed. Patient and health care team satisfaction also was measured. Care coordination interventions included: telehealth, group visits, standardized individual patient education, as well as creative uses of the electronic medical record for workflow changes, daily huddles, and monthly meetings. The results were positive, statistically significant differences in the pre and post scores for A1c (P = .001, n = 790), foot exam (P = .001, n = 850), and microalbumin (P = .01, n = 850). Post intervention, patient and health care team satisfaction with the RNCC role was high (mean scores ≥3 on a 5-point Likert scale). Integrating the RNCC within a multidisciplinary team in the PCMH had a significant positive impact on diabetic quality indicators. Patient and health care team satisfaction with the RNCC role was high. PMID:25632926

  17. Deletions in the Gibberellin Biosynthesis Gene Cluster of Gibberella fujikuroi by Restriction Enzyme-Mediated Integration and Conventional Transformation-Mediated Mutagenesis

    PubMed Central

    Linnemannstöns, Pia; Voß, Thorsten; Hedden, Peter; Gaskin, Paul; Tudzynski, Bettina

    1999-01-01

    We induced mutants of Gibberella fujikuroi deficient in gibberellin (GA) biosynthesis by transformation-mediated mutagenesis with the vector pAN7-1. We recovered 24 GA-defective mutants in one of nine transformation experiments performed without the addition of a restriction enzyme. Each mutant had a similar Southern blot pattern, suggesting the integration of the vector into the same site. The addition of a restriction enzyme by restriction enzyme-mediated integration (REMI) significantly increased the transformation rate and the rate of single-copy integration events. Of 1,600 REMI transformants, two produced no GAs. Both mutants had multiple copies of the vector pAN7-1 and one had a Southern blot pattern similar to those of the 24 conventionally transformed GA-deficient mutants. Biochemical analysis of the two REMI mutants confirmed that they cannot produce ent-kaurene, the first specific intermediate of the GA pathway. Feeding the radioactively labelled precursors ent-kaurene and GA12-aldehyde followed by high-performance liquid chromatography and gas chromatography-mass spectrometry analysis showed that neither of these intermediates was converted to GAs in the mutants. Southern blot analysis and pulsed-field gel electrophoresis of the transformants using the bifunctional ent-copalyl diphosphate/ent-kaurene synthase gene (cps/ks) and the flanking regions as probes revealed a large deletion in the GA-deficient REMI transformants and in the GA-deficient transformants obtained by conventional insertional transformation. We conclude that transformation procedures with and without the addition of restriction enzymes can lead to insertion-mediated mutations and to deletions and chromosome translocations. PMID:10347043

  18. Multivariate Calibration and Model Integrity for Wood Chemistry Using Fourier Transform Infrared Spectroscopy

    PubMed Central

    Zhou, Chengfeng; Jiang, Wei; Cheng, Qingzheng; Via, Brian K.

    2015-01-01

    This research addressed a rapid method to monitor hardwood chemical composition by applying Fourier transform infrared (FT-IR) spectroscopy, with particular interest in model performance for interpretation and prediction. Partial least squares (PLS) and principal components regression (PCR) were chosen as the primary models for comparison. Standard laboratory chemistry methods were employed on a mixed genus/species hardwood sample set to collect the original data. PLS was found to provide better predictive capability while PCR exhibited a more precise estimate of loading peaks and suggests that PCR is better for model interpretation of key underlying functional groups. Specifically, when PCR was utilized, an error in peak loading of ±15 cm−1 from the true mean was quantified. Application of the first derivative appeared to assist in improving both PCR and PLS loading precision. Research results identified the wavenumbers important in the prediction of extractives, lignin, cellulose, and hemicellulose and further demonstrated the utility in FT-IR for rapid monitoring of wood chemistry. PMID:26576321

  19. Multivariate Calibration and Model Integrity for Wood Chemistry Using Fourier Transform Infrared Spectroscopy.

    PubMed

    Zhou, Chengfeng; Jiang, Wei; Cheng, Qingzheng; Via, Brian K

    2015-01-01

    This research addressed a rapid method to monitor hardwood chemical composition by applying Fourier transform infrared (FT-IR) spectroscopy, with particular interest in model performance for interpretation and prediction. Partial least squares (PLS) and principal components regression (PCR) were chosen as the primary models for comparison. Standard laboratory chemistry methods were employed on a mixed genus/species hardwood sample set to collect the original data. PLS was found to provide better predictive capability while PCR exhibited a more precise estimate of loading peaks and suggests that PCR is better for model interpretation of key underlying functional groups. Specifically, when PCR was utilized, an error in peak loading of ±15 cm(-1) from the true mean was quantified. Application of the first derivative appeared to assist in improving both PCR and PLS loading precision. Research results identified the wavenumbers important in the prediction of extractives, lignin, cellulose, and hemicellulose and further demonstrated the utility in FT-IR for rapid monitoring of wood chemistry. PMID:26576321

  20. Integration of sexual trauma in a religious narrative: Transformation, resolution and growth among contemplative nuns

    PubMed Central

    Littlewood, Roland; Leavey, Gerard

    2013-01-01

    The psychological consequences of sexual abuse are generally serious and enduring, particularly when the perpetrator is known and trusted by the survivor. This paper explores the experiences of five contemplative nuns who were sexually abused by priests and the spiritual journeys that followed. In the context of an ethnographic study of contemplative practice, participant observation and in-depth interviews were used to examine the ways that the nuns sought to make sense of their experiences through a long process of solitary introspection. The pursuit of meaning was shaped by religious beliefs relating to forgiveness, sacrifice, and salvation. Thus, trauma was transformed into a symbolic religious narrative that shaped their sense of identity. They were able to restructure core beliefs and to manage their current relationships with priests more securely. They described regaining their spiritual well-being in ways that suggest a form of posttraumatic spiritual growth. We conclude by discussing the findings in the light of the existing literature on the interaction of trauma and spirituality. PMID:23296289

  1. Integration of sexual trauma in a religious narrative: transformation, resolution and growth among contemplative nuns.

    PubMed

    Durà-Vilà, Glòria; Littlewood, Roland; Leavey, Gerard

    2013-02-01

    The psychological consequences of sexual abuse are generally serious and enduring, particularly when the perpetrator is known and trusted by the survivor. This paper explores the experiences of five contemplative nuns who were sexually abused by priests and the spiritual journeys that followed. In the context of an ethnographic study of contemplative practice, participant observation and in-depth interviews were used to examine the ways that the nuns sought to make sense of their experiences through a long process of solitary introspection. The pursuit of meaning was shaped by religious beliefs relating to forgiveness, sacrifice, and salvation. Thus, trauma was transformed into a symbolic religious narrative that shaped their sense of identity. They were able to restructure core beliefs and to manage their current relationships with priests more securely. They described regaining their spiritual well-being in ways that suggest a form of posttraumatic spiritual growth. We conclude by discussing the findings in the light of the existing literature on the interaction of trauma and spirituality. PMID:23296289

  2. Boltzmann-Langevin theory of Coulomb drag

    NASA Astrophysics Data System (ADS)

    Chen, W.; Andreev, A. V.; Levchenko, A.

    2015-06-01

    We develop a Boltzmann-Langevin description of the Coulomb drag effect in clean double-layer systems with large interlayer separation d as compared to the average interelectron distance λF. Coulomb drag arises from density fluctuations with spatial scales of order d . At low temperatures, their characteristic frequencies exceed the intralayer equilibration rate of the electron liquid, and Coulomb drag may be treated in the collisionless approximation. As temperature is raised, the electron mean free path becomes short due to electron-electron scattering. This leads to local equilibration of electron liquid, and consequently drag is determined by hydrodynamic density modes. Our theory applies to both the collisionless and the hydrodynamic regimes, and it enables us to describe the crossover between them. We find that drag resistivity exhibits a nonmonotonic temperature dependence with multiple crossovers at distinct energy scales. At the lowest temperatures, Coulomb drag is dominated by the particle-hole continuum, whereas at higher temperatures of the collision-dominated regime it is governed by the plasmon modes. We observe that fast intralayer equilibration mediated by electron-electron collisions ultimately renders a stronger drag effect.

  3. BRST invariance in Coulomb gauge QCD

    NASA Astrophysics Data System (ADS)

    Andraši, A.; Taylor, J. C.

    2015-12-01

    In the Coulomb gauge, the Hamiltonian of QCD contains terms of order ħ2, identified by Christ and Lee, which are non-local but instantaneous. The question is addressed how do these terms fit in with BRST invariance. Our discussion is confined to the simplest, O(g4) , example.

  4. Coulombic Effects in Ion Mobility Spectrometry

    PubMed Central

    Tolmachev, Aleksey V.; Clowers, Brian H.; Belov, Mikhail E.; Smith, Richard D.

    2009-01-01

    Ion mobility spectrometry (IMS) has been increasingly employed in a number of applications. When coupled to mass spectrometry (MS), IMS becomes a powerful analytical tool for separating complex samples and investigating molecular structure. Therefore, improvements in IMS-MS instrumentation, e.g. IMS resolving power and sensitivity, are highly desirable. Implementation of an ion trap for accumulation and pulsed ion injection to IMS based on the ion funnel has provided considerably increased ion currents, and thus a basis for improved sensitivity and measurement throughput. However, large ion populations may manifest Coulombic effects contributing to the spatial dispersion of ions traveling in the IMS drift tube, and reduction in the IMS resolving power. In this study, we present an analysis of Coulombic effects on IMS resolution. Basic relationships have been obtained for the spatial evolution of ion packets due to Coulombic repulsion. The analytical relationships were compared with results of a computer model that simulates IMS operation based on a first principles approach. Initial experimental results reported here are consistent with the computer modeling. A noticeable decrease in the IMS resolving power was observed for ion populations of >10,000 elementary charges. The optimum IMS operation conditions which would minimize the Coulombic effects are discussed. PMID:19438247

  5. The Pioneer Anomaly as a Coulomb Attraction

    NASA Astrophysics Data System (ADS)

    Morris, Steven

    2016-06-01

    The anomalous acceleration of the Pioneer 10 and Pioneer 11 spacecraft can be explained as a Coulomb attraction between the positively-charged Solar System (due to cosmic rays) and the negatively-charged spacecraft (due to alpha-particle emission from the radioisotope thermoelectric generators).

  6. Thermodynamic Theory of Spherically Trapped Coulomb Clusters

    NASA Astrophysics Data System (ADS)

    Wrighton, Jeffrey; Dufty, James; Bonitz, Michael; K"{A}Hlert, Hanno

    2009-11-01

    The radial density profile of a finite number of identical charged particles confined in a harmonic trap is computed over a wide ranges of temperatures (Coulomb coupling) and particle numbers. At low temperatures these systems form a Coulomb crystal with spherical shell structure which has been observed in ultracold trapped ions and in dusty plasmas. The shell structure is readily reproduced in simulations. However, analytical theories which used a mean field approachfootnotetext[1]C. Henning et al., Phys. Rev. E 74, 056403 (2006) or a local density approximationfootnotetext[2]C. Henning et al., Phys. Rev. E 76, 036404 (2007) have, so far, only been able to reproduce the average density profile. Here we present an approach to Coulomb correlations based on the hypernetted chain approximation with additional bridge diagrams. It is demonstrated that this model reproduces the correct shell structure within a few percent and provides the basis for a thermodynamic theory of Coulomb clusters in the strongly coupled fluid state.footnotetext[3]J. Wrighton, J.W. Dufty, H. K"ahlert and M. Bonitz, J. Phys. A 42, 214052 (2009) and Phys. Rev. E (2009) (to be submitted)

  7. Molecular Dynamics Simulations of Coulomb Explosion

    SciTech Connect

    Bringa, E M

    2002-05-17

    A swift ion creates a track of electronic excitations in the target material. A net repulsion inside the track can cause a ''Coulomb Explosion'', which can lead to damage and sputtering of the material. Here we report results from molecular-dynamics (MD) simulations of Coulomb explosion for a cylindrical track as a function of charge density and neutralization/quenching time, {tau}. Screening by the free electrons is accounted for using a screened Coulomb potential for the interaction among charges. The yield exhibits a prompt component from the track core and a component, which dominates at higher excitation density, from the heated region produced. For the cases studied, the number of atoms ejected per incident ion, i.e. the sputtering yield Y, is quadratic with charge density along the track as suggested by simple models. Y({tau} = 0.2 Debye periods) is nearly 20% of the yield when there is no neutralization ({tau} {yields} {infinity}). The connections between ''Coulomb explosions'', thermal spikes and measurements of electronic sputtering are discussed.

  8. The Syrian hamster embryo cells transformation assay identifies efficiently nongenotoxic carcinogens, and can contribute to alternative, integrated testing strategies.

    PubMed

    Benigni, Romualdo; Bossa, Cecilia; Tcheremenskaia, Olga; Battistelli, Chiara Laura; Giuliani, Alessandro

    2015-02-01

    The long-term carcinogenesis bioassays have played a central role in protecting human health, but for ethical and practical reasons their use is dramatically diminishing and the genotoxicity short-term tests have taken the pivotal role in the pre-screening of chemical carcinogenicity. However, this strategy cannot detect nongenotoxic carcinogens. Since up to 25% of IARC human carcinogens are recognized to have nongenotoxic mechanisms of action, the risk they pose to human health cannot be disregarded, and it is urgent to fill the gap in the tools for alternative testing. In this paper, we analyze from different perspectives the ability of Cell Transformation Assays to identify nongenotoxic carcinogens, and we conclude that the Syrian hamster embryo cells test is able to identify nongenotoxic carcinogens with 80-90% efficiency, and thus, can play an important role in integrated, alternative testing strategies. PMID:25813724

  9. Efficient compression of motion-compensated sub-images with Karhunen-Loeve transform in three-dimensional integral imaging

    NASA Astrophysics Data System (ADS)

    Kang, Ho-Hyun; Shin, Dong-Hak; Kim, Eun-Soo

    2010-03-01

    An approach to highly enhance the compression efficiency of the integral images by applying the Karhunen-Loeve transform (KLT) algorithm to the motion-compensated sub-images is proposed. The sub-images transformed from the elemental images picked-up from the three-dimensional (3D) object might represent the different perspectives of the object. Thus, the similarity among the sub-images gets better than that among the elemental images, so that an improvement of compression efficiency of the sub-images could be obtained. However, motion vectors occurred among the sub-images might result in an additional increase of image data to be compressed. Accordingly, in this paper, motion vectors have been estimated and compensated in all sub-image in advance. Then the KLT algorithm was applied to these motion-compensated sub-images for compression. It is shown from some experimental results that compression efficiency of the proposed method has been improved up to 24.44%, 40.62%, respectively, on the average compared to that of the conventional KLT compression method and that of the JPEG.

  10. Two-dimensional Coulomb scattering of a quantum particle: Wave functions and Green's functions

    NASA Astrophysics Data System (ADS)

    Pupyshev, V. V.

    2016-02-01

    We solve the problem of the propagation of a charged quantum particle in a two-dimensional plane embedded in the three-dimensional coordinate space. We consider scattering of this particle by a stable Coulomb center situated in the same plane. We study the wave function of this particle, its Green's function, and all radial components of these functions. We derive uniform majorant bounds on absolute values of these functions and find the wave function representation in terms of regular radial Coulomb functions and the scattering amplitude representation via partial phases. We obtain integral representations of the Greens's function and all its radial components.

  11. FTIR (Fourier transform infrared) spectrophotometry for thin film monitors: Computer and equipment integration for enhanced capabilities

    SciTech Connect

    Cox, J.N.; Sedayao, J.; Shergill, G.; Villasol, R. ); Haaland, D.M. )

    1990-01-01

    Fourier transform infrared spectrophotometry (FTIR) is a valuable technique for monitoring thin films used in semiconductor device manufacture. Determinations of the constituent contents in borophosphosilicate (BPSG), phosphosilicate (PSG), silicon oxynitride (SiON:H,OH), and spin-on-glass (SOG) thin films are a few applications. Due to the nature of the technique, FTIR instrumentation is one of the most extensively computer-dependent pieces of equipment that is likely to be found in a microelectronics plant. In the role of fab monitor or reactor characterization tool, FTIR instruments can rapidly generate large amounts of data. By linking a local FTIR data station to a remote minicomputer its capabilities are greatly improved. We discuss three caused of enhancement. First, the FTIR in the fab area communicates and interacts in real time with the minicomputer: transferring data segments to it, instructing it to perform sophisticated processing, and returning the result to the operator in the fab. Characterizations of PSG thin films by this approach are discussed. Second, the spectra of large numbers of samples are processed locally. The large database is then transmitted to the minicomputer for study by statistical/graphics software. Results of CVD-reactor spatial profiling experiments for plasma SiON are presented. Third, processing of calibration spectra is performed on the minicomputer to optimize the accuracy and precision of a Partial Least Squares'' analysis mode. This model is then transferred to the data station in the fab. The analysis of BPSG thin films is discussed in this regard. The prospects for fully automated at-line monitoring and for real-time, in-situ monitoring will be discussed. 10 refs., 4 figs.

  12. Remote Spacecraft Attitude Control by Coulomb Charging

    NASA Astrophysics Data System (ADS)

    Stevenson, Daan

    The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to

  13. Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots

    NASA Astrophysics Data System (ADS)

    Keller, A. J.; Lim, J. S.; Sánchez, David; López, Rosa; Amasha, S.; Katine, J. A.; Shtrikman, Hadas; Goldhaber-Gordon, D.

    2016-08-01

    In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.

  14. Measurement of the 92,93,94,100Mo(γ,n) reactions by Coulomb Dissociation

    NASA Astrophysics Data System (ADS)

    Göbel, K.; Adrich, P.; Altstadt, S.; Alvarez-Pol, H.; Aksouh, F.; Aumann, T.; Babilon, M.; Behr, K.-H.; Benlliure, J.; Berg, T.; Böhmer, M.; Boretzky, K.; Brünle, A.; Beyer, R.; Casarejos, E.; Chartier, M.; Cortina-Gil, D.; Chatillon, A.; Datta Pramanik, U.; Deveaux, L.; Elvers, M.; Elze, T. W.; Emling, H.; Erhard, M.; Ershova; Fernandez-Dominguez, B.; Geissel, H.; Górska, M.; Heftrich, T.; Heil, M.; Hellstroem, M.; Ickert, G.; Johansson, H.; Junghans, A. R.; Käppeler, F.; Kiselev, O.; Klimkiewicz, A.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lindenberg, K.; Litvinov, Y. A.; Maierbeck, P.; Movsesyan, A.; Müller, S.; Nilsson, T.; Nociforo, C.; Paar, N.; Palit, R.; Paschalis, S.; Plag, R.; Prokopowicz, W.; Reifarth, R.; Rossi, D. M.; Schnorrenberger, L.; Simon, H.; Sonnabend, K.; Sümmerer, K.; Surówka, G.; Vretenar, D.; Wagner, A.; Walter, S.; Waluś, W.; Wamers, F.; Weick, H.; Weigand, M.; Winckler, N.; Winkler, M.; Zilges, A.

    2016-01-01

    The Coulomb Dissociation (CD) cross sections of the stable isotopes 92,94,100Mo and of the unstable isotope 93Mo were measured at the LAND/R3B setup at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Experimental data on these isotopes may help to explain the problem of the underproduction of 92,94Mo and 96,98Ru in the models of p-process nucleosynthesis. The CD cross sections obtained for the stable Mo isotopes are in good agreement with experiments performed with real photons, thus validating the method of Coulomb Dissociation. The result for the reaction 93Mo(γ,n) is especially important since the corresponding cross section has not been measured before. A preliminary integral Coulomb Dissociation cross section of the 94Mo(γ,n) reaction is presented. Further analysis will complete the experimental database for the (γ,n) production chain of the p-isotopes of molybdenum.

  15. A Monte Carlo study of the generalized Coulomb Milne problem

    NASA Astrophysics Data System (ADS)

    Barghouthi, I.; Barakat, A.

    2003-04-01

    Because of its relevance to the solar wind and terrestrial polar wind, we investigated the problem where a swarm of minor ions escaped through a background of non-uniform major ions. The Fokker-Planck expression was used to represent the Coulomb collisions between the minor and major ions. A change of variables was utilized in order to transform the problem into a simpler form where the background medium was uniform. This transformed problem described minor ions diffusing through a background of ions of a constant density in the semi-infinite region (z>0), and vacuum in the region (z<0), which resembles the standard Milne problem. A Monte Carlo model was used to investigate this "generalized Coulomb Milne" problem for three different minor-to-major ion mass ratios, namely; R = m/M = 1/16, 1 and 16, where m and M are the minor and major ion masses, respectively. The minor ions' velocity distribution function and velocity moments (i.e. density, drift velocity, parallel and perpendicular temperatures, and parallel and perpendicular heat fluxes) were computed. The following conclusions can be drawn: (1) In general, the minor ion species for the cases of (R=1,16) show very similar characteristics, while the third case (R=1/16) shows very different characteristics. (2) In the collision-dominated region (z>>1), the gradient of the normalized density profile approaches a constant value. This asymptotic value of the gradient increases when R decreases. (3) As the minor ion species drifts from the collision-dominated region (z>>) to the collisionless region (z<<1), its velocity distribution starts as Maxwellian, then it develops a tail in the (-z) direction, and finally reaches a form close to bi-Maxwellian. The case of (R=1/16) develops a relatively more pronounced tail, and displays a double-hump form, which is absent for the other two cases. (4) The heat flux profile for the case of (R=1/6) in the collision-dominated region exceeds the corresponding values from the other

  16. Hilbert transform and exponential integral estimates of rectangular sums of double Fourier series

    NASA Astrophysics Data System (ADS)

    Karagulyan, G. A.

    1996-04-01

    A new integral estimate for rectangular partial sums of double Fourier series is obtained. The main result of the paper is the following.Theorem. For any f\\in L\\log L(\\mathbf T^2) and \\delta>0 there exists a set E_{\\delta,f}\\in\\mathbf T^2, \\vert E_{\\delta,f}\\vert>(2\\pi)^2-\\delta such that \\displaystyle 1)\\quad\\int_{E_{\\delta,f}}\\exp\\biggl\\lbrack\\frac{c_1\\delta\\vert ......L(\\mathbf T^2)}}\\biggr\\rbrack^{1/2}\\,dx\\,dy\\leqslant C_2, \\qquad N,M=1,2,\\dots, \\displaystyle 2)\\quad\\lim_{N,M\\to\\infty}\\int_{E_{\\delta,f}}\\bigl\\lbrack\\exp(\\vert S_{N,M}(x,y,f)-f(x,y)\\vert)^{1/2}-1\\bigr\\rbrack\\,dx\\,dy=0. This theorem yields estimates almost everywhere for rectangular sums of double Fourier series and convergence in L^p on sets of large measure.

  17. Caring Science: Transforming the Ethic of Caring-Healing Practice, Environment, and Culture within an Integrated Care Delivery System.

    PubMed

    Foss Durant, Anne; McDermott, Shawna; Kinney, Gwendolyn; Triner, Trudy

    2015-01-01

    In early 2010, leaders within Kaiser Permanente (KP) Northern California's Patient Care Services division embarked on a journey to embrace and embed core tenets of Caring Science into the practice, environment, and culture of the organization. Caring Science is based on the philosophy of Human Caring, a theory articulated by Jean Watson, PhD, RN, AHN-BC, FAAN, as a foundational covenant to guide nursing as a discipline and a profession. Since 2010, Caring Science has enabled KP Northern California to demonstrate its commitment to being an authentic person- and family-centric organization that promotes and advocates for total health. This commitment empowers KP caregivers to balance the art and science of clinical judgment by considering the needs of the whole person, honoring the unique perception of health and healing that each member or patient holds, and engaging with them to make decisions that nurture their well-being. The intent of this article is two-fold: 1) to provide context and background on how a professional practice framework was used to transform the ethic of caring-healing practice, environment, and culture across multiple hospitals within an integrated delivery system; and 2) to provide evidence on how integration of Caring Science across administrative, operational, and clinical areas appears to contribute to meaningful patient quality and health outcomes. PMID:26828076

  18. Coulomb Stress Accumulation along the San Andreas Fault System

    NASA Technical Reports Server (NTRS)

    Smith, Bridget; Sandwell, David

    2003-01-01

    Stress accumulation rates along the primary segments of the San Andreas Fault system are computed using a three-dimensional (3-D) elastic half-space model with realistic fault geometry. The model is developed in the Fourier domain by solving for the response of an elastic half-space due to a point vector body force and analytically integrating the force from a locking depth to infinite depth. This approach is then applied to the San Andreas Fault system using published slip rates along 18 major fault strands of the fault zone. GPS-derived horizontal velocity measurements spanning the entire 1700 x 200 km region are then used to solve for apparent locking depth along each primary fault segment. This simple model fits remarkably well (2.43 mm/yr RMS misfit), although some discrepancies occur in the Eastern California Shear Zone. The model also predicts vertical uplift and subsidence rates that are in agreement with independent geologic and geodetic estimates. In addition, shear and normal stresses along the major fault strands are used to compute Coulomb stress accumulation rate. As a result, we find earthquake recurrence intervals along the San Andreas Fault system to be inversely proportional to Coulomb stress accumulation rate, in agreement with typical coseismic stress drops of 1 - 10 MPa. This 3-D deformation model can ultimately be extended to include both time-dependent forcing and viscoelastic response.

  19. Phase-integral solution of the radial Dirac equation

    SciTech Connect

    Linnaeus, Staffan

    2010-03-15

    A phase-integral (WKB) solution of the radial Dirac equation is constructed, retaining perfect symmetry between the two components of the wave function and introducing no singularities except at the classical transition points. The potential is allowed to be the time component of a four-vector, a Lorentz scalar, a pseudoscalar, or any combination of these. The key point in the construction is the transformation from two coupled first-order equations constituting the radial Dirac equation to a single second-order Schroedinger-type equation. This transformation can be carried out in infinitely many ways, giving rise to different second-order equations but with the same spectrum. A unique transformation is found that produces a particularly simple second-order equation and correspondingly simple and well-behaved phase-integral solutions. The resulting phase-integral formulas are applied to unbound and bound states of the Coulomb potential. For bound states, the exact energy levels are reproduced.

  20. Transforming trauma healthcare delivery in rural areas by use of an integrated call center

    PubMed Central

    Agrawal, Deepak

    2012-01-01

    Introduction: There is poor penetration of trauma healthcare delivery in rural areas. On the other hand, mobile penetration in India is now averaging 80% with most families having access to mobile phone. Aims and Objectives: The aim of this study was to assess the implementation and socioeconomic impact of a call center in providing healthcare delivery for patients with head and spinal injuries. Materials and Methods: This was a prospective observational study carried out over a 6-month period at a level I trauma Center in New Delhi, India. A nine-seater call center was outsourced to a private company and the hospital's electronic medical records were integrated with the call-center operations. The call center was given responsibility of maintaining appointments and scheduling clinics for the whole hospital as well as ensuring follow-up visits. Trained call-center staff handled simple patient queries and referred the rest via email to concerned doctors. A telephonic survey was done prior to the start of call-center operations and after 3 months to assess for user satisfaction. Results: The initial cost of outsourcing the call center was Rs 1.6 lakhs (US$ 4000), with a recurring cost of Rs 80,000 (US$ 2000) per month. A total of 484 patients were admitted in the department of Neurosurgery during the study period. Of these, 63% (n=305) were from rural areas. Patients’ overall experience for clinic visits improved markedly following implementation of call center. Patient satisfaction for follow-up visits increased from a mean of 32-96%. Ninety-five percent patients reported a significant decrease in waiting time in clinics 80.4% reporting improved doctor-patient interaction. A total of 52 visits could be postponed/cancelled for patients living in far flung areas resulting in major socioeconomic benefits to these families. Conclusions: As shown by our case study, call centers have the potential to revolutionize delivery of trauma healthcare to rural areas in an

  1. Coulomb crystallization of highly charged ions

    NASA Astrophysics Data System (ADS)

    Schmöger, L.; Versolato, O. O.; Schwarz, M.; Kohnen, M.; Windberger, A.; Piest, B.; Feuchtenbeiner, S.; Pedregosa-Gutierrez, J.; Leopold, T.; Micke, P.; Hansen, A. K.; Baumann, T. M.; Drewsen, M.; Ullrich, J.; Schmidt, P. O.; López-Urrutia, J. R. Crespo

    2015-03-01

    Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb crystallization of HCIs (specifically 40Ar13+) produced in an electron beam ion trap and retrapped in a cryogenic linear radiofrequency trap by means of sympathetic motional cooling through Coulomb interaction with a directly laser-cooled ensemble of Be+ ions. We also demonstrate cooling of a single Ar13+ ion by a single Be+ ion—the prerequisite for quantum logic spectroscopy with a potential 10-19 accuracy level. Achieving a seven-orders-of-magnitude decrease in HCI temperature starting at megakelvin down to the millikelvin range removes the major obstacle for HCI investigation with high-precision laser spectroscopy.

  2. Coulomb drag in topological insulator films

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Liu, Weizhe Edward; Culcer, Dimitrie

    2016-05-01

    We study Coulomb drag between the top and bottom surfaces of topological insulator films. We derive a kinetic equation for the thin-film spin density matrix containing the full spin structure of the two-layer system, and analyze the electron-electron interaction in detail in order to recover all terms responsible for Coulomb drag. Focusing on typical topological insulator systems, with a film thicknesses d up to 6 nm, we obtain numerical and approximate analytical results for the drag resistivity ρD and find that ρD is proportional to T2d-4 na-3/2 np-3/2 at low temperature T and low electron density na,p, with a denoting the active layer and p the passive layer. In addition, we compare ρD with graphene, identifying qualitative and quantitative differences, and we discuss the multi-valley case, ultra thin films and electron-hole layers.

  3. Coulomb wave functions in momentum space

    SciTech Connect

    Eremenko, V; Upadhyay, N. J.; Thompson, I J; Elster, Charlotte; Nunes, F. M.; Arbanas, Goran; Escher, J.E.; Hlophe, L.

    2015-01-01

    An algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space is presented. The arguments are the Sommerfeld parameter eta, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p -> q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical bar in the range of 10(-1) to 10, and thus is particularly suited for momentum space calculations of nuclear reactions. Program Summary Program title: libcwfn Catalogue identifier: AEUQ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEUQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 864503 No. of bytes in distributed program, including test data, etc.: 7178021 Distribution format: tar.gz Programming language: Fortran 90, Fortran 77, Python, make (GNU Make dialect), GNU Bash shell interpreter (available as /bin/bash). Computer: Apple Powermac (Intel Xeon), ASUS K53U (AMD E-350 (Dual Core)), DELL Precision T3500 (Intel Xeon), NERSC Carver (Intel Nehalem Quad Core). Operating system: Linux, Windows (using Cygwin). RAM: less than 512 Mbytes Classification: 17.8, 17.13, 17.16. Nature of problem: The calculation of partial wave Coulomb functions with integer land all other arguments real. Solution method: Computing the value of the function using explicit formulae and algorithms. Running time: Less than 10(-3) s. (C) 2014 Elsevier B.V. All rights reserved.

  4. Coulomb wave functions in momentum space

    DOE PAGESBeta

    Eremenko, V; Upadhyay, N. J.; Thompson, I J; Elster, Charlotte; Nunes, F. M.; Arbanas, Goran; Escher, J.E.; Hlophe, L.

    2015-01-01

    An algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space is presented. The arguments are the Sommerfeld parameter eta, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p -> q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical barmore » in the range of 10(-1) to 10, and thus is particularly suited for momentum space calculations of nuclear reactions. Program Summary Program title: libcwfn Catalogue identifier: AEUQ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEUQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 864503 No. of bytes in distributed program, including test data, etc.: 7178021 Distribution format: tar.gz Programming language: Fortran 90, Fortran 77, Python, make (GNU Make dialect), GNU Bash shell interpreter (available as /bin/bash). Computer: Apple Powermac (Intel Xeon), ASUS K53U (AMD E-350 (Dual Core)), DELL Precision T3500 (Intel Xeon), NERSC Carver (Intel Nehalem Quad Core). Operating system: Linux, Windows (using Cygwin). RAM: less than 512 Mbytes Classification: 17.8, 17.13, 17.16. Nature of problem: The calculation of partial wave Coulomb functions with integer land all other arguments real. Solution method: Computing the value of the function using explicit formulae and algorithms. Running time: Less than 10(-3) s. (C) 2014 Elsevier B.V. All rights reserved.« less

  5. Ultrashort pulses in graphene with Coulomb impurities

    NASA Astrophysics Data System (ADS)

    Konobeeva, N. N.; Belonenko, M. B.

    2016-06-01

    We have investigated the propagation of an electromagnetic field in graphene with impurities, including the two-dimensional case. The spectrum of electrons for the graphene subsystem is taken from a model that takes into account Coulomb impurities. Based on Maxwell's equations, we have obtained an effective equation for the vector potential of the electromagnetic field. It has been revealed that the pulse shape depends on free parameters.

  6. The scattering of the screened Coulomb potential

    NASA Astrophysics Data System (ADS)

    Cao, Xin-Wei; Chen, Wen-Li; Li, Yuan-Yuan; Wei, Gao-Feng

    2014-08-01

    We study the scattering states of the screened Coulomb potential in the nonrelativistic frame. The explicitly calculation formula of phase shift is derived and the normalized radial wave functions of scattering states on the ^{\\prime} k/2\\pi scale^{\\prime} are presented. By studying analytical properties of scattering amplitude the screening effects on bound states are discussed numerically. It is shown that the screening effects increase with increasing screened parameter, especially for large quantum states.

  7. A program system for ab initio MO calculations on vector and parallel processing machines III. Integral reordering and four-index transformation

    NASA Astrophysics Data System (ADS)

    Wiest, Roland; Demuynck, Jean; Bénard, Marc; Rohmer, Marie-Madeleine; Ernenwein, René

    1991-01-01

    This series of three papers presents a program system for ab initio molecular orbital calculations on vector and parallel computers. Part III is devoted to the four-index transformation on a molecular orbital basis of size NMO of the file of two-electron integrals ( pq∥ rs) generated by a contracted Gaussian set of size NATO (number of atomic orbitals). A fast Yoshimine algorithm first sorts the ( pq∥ rs) integrals with respect to index pq only. This file of half-sorted integrals labelled by their rs-index can be processed without further modification to generate either the transformed integrals or the supermatrix elements. The large memory available on the CRAY-2 has made possible to implement the transformation algorithm proposed by Bender in 1972, which requires a core-storage allocation varying as (NATO) 3. Two versions of Bender's algorithm are included in the present program. The first version is an in-core version, where the complete file of accumulated contributions to transformed integrals is stored and updated in central memory. This version has been parallelized by distributing over a limited number of logical tasks the NATO steps corresponding to the scanning of the most external loop. The second version is an out-of-core version, in which twin fires are alternatively used as input and output for the accumulated contributions to transformed integrals. This version is not parallel. The choice of one or another version and (for version 1) the determination of the number of tasks depends upon the balance between the available and the requested amounts of storage. The storage management and the choice of the proper version are carried out automatically using dynamic storage allocation. Both versions are vectorized and take advantage of the molecular symmetry.

  8. Dynamics of Coulombic and gravitational periodic systems

    NASA Astrophysics Data System (ADS)

    Kumar, Pankaj; Miller, Bruce N.

    2016-04-01

    We study the dynamics and the phase-space structures of Coulombic and self-gravitating versions of the classical one-dimensional three-body system with periodic boundary conditions. We demonstrate that such a three-body system may be reduced isomorphically to a spatially periodic system of a single particle experiencing a two-dimensional potential on a rhombic plane. For the case of both Coulombic and gravitational versions, exact expressions of the Hamiltonian have been derived in rhombic coordinates. We simulate the phase-space evolution through an event-driven algorithm that utilizes analytic solutions to the equations of motion. The simulation results show that the motion exhibits chaotic, quasiperiodic, and periodic behaviors in segmented regions of the phase space. While there is no evidence of global chaos in either the Coulombic or the gravitational system, the former exhibits a transition from a completely nonchaotic phase space at low energies to a mixed behavior. Gradual yet striking transitions from mild to intense chaos are indicated with changing energy, a behavior that differentiates the spatially periodic systems studied in this Rapid Communication from the well-understood free-boundary versions of the three-body problem. Our treatment of the three-body systems opens avenues for analysis of the dynamical properties exhibited by spatially periodic versions of various classes of systems studied in plasma and gravitational physics as well as in cosmology.

  9. Dynamics of Coulombic and gravitational periodic systems.

    PubMed

    Kumar, Pankaj; Miller, Bruce N

    2016-04-01

    We study the dynamics and the phase-space structures of Coulombic and self-gravitating versions of the classical one-dimensional three-body system with periodic boundary conditions. We demonstrate that such a three-body system may be reduced isomorphically to a spatially periodic system of a single particle experiencing a two-dimensional potential on a rhombic plane. For the case of both Coulombic and gravitational versions, exact expressions of the Hamiltonian have been derived in rhombic coordinates. We simulate the phase-space evolution through an event-driven algorithm that utilizes analytic solutions to the equations of motion. The simulation results show that the motion exhibits chaotic, quasiperiodic, and periodic behaviors in segmented regions of the phase space. While there is no evidence of global chaos in either the Coulombic or the gravitational system, the former exhibits a transition from a completely nonchaotic phase space at low energies to a mixed behavior. Gradual yet striking transitions from mild to intense chaos are indicated with changing energy, a behavior that differentiates the spatially periodic systems studied in this Rapid Communication from the well-understood free-boundary versions of the three-body problem. Our treatment of the three-body systems opens avenues for analysis of the dynamical properties exhibited by spatially periodic versions of various classes of systems studied in plasma and gravitational physics as well as in cosmology. PMID:27176238

  10. The Fourier transform method and the SD-bar approach for the analytical and numerical treatment of multicenter overlap-like quantum similarity integrals

    SciTech Connect

    Safouhi, Hassan . E-mail: hassan.safouhi@ualberta.ca; Berlu, Lilian

    2006-07-20

    Molecular overlap-like quantum similarity measurements imply the evaluation of overlap integrals of two molecular electronic densities related by Dirac delta function. When the electronic densities are expanded over atomic orbitals using the usual LCAO-MO approach (linear combination of atomic orbitals), overlap-like quantum similarity integrals could be expressed in terms of four-center overlap integrals. It is shown that by introducing the Fourier transform of delta Dirac function in the integrals and using the Fourier transform approach combined with the so-called B functions, one can obtain analytic expressions of the integrals under consideration. These analytic expressions involve highly oscillatory semi-infinite spherical Bessel functions, which are the principal source of severe numerical and computational difficulties. In this work, we present a highly efficient algorithm for a fast and accurate numerical evaluation of these multicenter overlap-like quantum similarity integrals over Slater type functions. This algorithm is based on the SD-bar approach due to Safouhi. Recurrence formulae are used for a better control of the degree of accuracy and for a better stability of the algorithm. The numerical result section shows the efficiency of our algorithm, compared with the alternatives using the one-center two-range expansion method, which led to very complicated analytic expressions, the epsilon algorithm and the nonlinear D-bar transformation.

  11. Nouvelle methode d'integration energetique pour la retro-installation des procedes industriels et la transformation des usines papetieres

    NASA Astrophysics Data System (ADS)

    Bonhivers, Jean-Christophe

    The increase in production of goods over the last decades has led to the need for improving the management of natural resources management and the efficiency of processes. As a consequence, heat integration methods for industry have been developed. These have been successful for the design of new plants: the integration principles are largely employed, and energy intensity has dramatically decreased in many processes. Although progress has also been achieved in integration methods for retrofit, these methods still need further conceptual development. Furthermore, methodological difficulties increase when trying to retrofit heat exchange networks that are closely interrelated to water networks, such as the case of pulp and paper mills. The pulp and paper industry seeks to increase its profitability by reducing production costs and optimizing supply chains. Recent process developments in forestry biorefining give this industry the opportunity for diversification into bio-products, increasing potential profit margins, and at the same time modernizing its energy systems. Identification of energy strategies for a mill in a changing environment, including the possibility of adding a biorefinery process on the industrial site, requires better integration methods for retrofit situations. The objective of this thesis is to develop an energy integration method for the retrofit of industrial systems and the transformation of pulp and paper mills, ant to demonstrate the method in case studies. Energy is conserved and degraded in a process. Heat can be converted into electricity, stored as chemical energy, or rejected to the environment. A systematic analysis of successive degradations of energy between the hot utilities until the environment, through process operations and existing heat exchangers, is essential in order to reduce the heat consumption. In this thesis, the "Bridge Method" for energy integration by heat exchanger network retrofit has been developed. This method

  12. Path Integrals, BRST Identities, and Regularization Schemes in Nonstandard Gauges

    NASA Astrophysics Data System (ADS)

    Ren, Hai-cang

    2000-07-01

    The path integral of a gauge theory is studied in Coulomb-like gauges. The Christ-Lee terms of operator ordering are reproduced within the path integration framework. In the presence of fermions, a new operator term, in addition to that of Christ and Lee, is discovered. Such terms are found to be instrumental in restoring the invariance of the effective Lagrangian under a field-dependent gauge transformation, which underlies the BRST symmetry. A unitary regularization scheme which maintains manifest BRST symmetry and is free from energy divergences is proposed for a nonabelian gauge field.

  13. Site-specific recombination for precise and clean transgene integration in plant genome. In: Touraev, A., Citovsky, V., Tzfira, T., Editors of book. Plant Transformation Technologies.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant Transformation Technologies is a comprehensive, authoritative book focusing on cutting-edge plant biotechnologies, offering in-depth, forward-looking information on methods for controlled and accurate genetic engineering. In response to ever-increasing pressure for precise and efficient integr...

  14. How Change Occurred at the Stoughton Area School District: Lessons from a SWIFT (Schoolwide Integrated Framework for Transformation) Knowledge Development Site. Issue Brief #3

    ERIC Educational Resources Information Center

    Stonemeier, Jennifer; Trader, Barbara; Kingston, Mary; Richards, Curtis; Blank, Rolf; East, Bill

    2014-01-01

    The SWIFT Center (Schoolwide Integrated Framework for Transformation) is an initiative to bring about educational equity district by district until all students excel, including students with the most profound needs. As the national technical assistance center to build schoolwide inclusive practices to improve academic and behavioral outcomes for…

  15. Covariant Transform

    NASA Astrophysics Data System (ADS)

    Kisil, Vladimir V.

    2011-03-01

    Dedicated to the memory of Cora Sadosky The paper develops theory of covariant transform, which is inspired by the wavelet construction. It was observed that many interesting types of wavelets (or coherent states) arise from group representations which are not square integrable or vacuum vectors which are not admissible. Covariant transform extends an applicability of the popular wavelets construction to classic examples like the Hardy space H2, Banach spaces, covariant functional calculus and many others.

  16. Coupling constant metamorphosis, the Staeckel transform and superintegrability

    SciTech Connect

    Post, Sarah

    2010-12-23

    This paper is dedicated to the memory of Marcos Moshinsky. In this paper, we discuss the important role that coupling constant metamorphosis (CCM) and the Staeckel transform have played in the analysis of superintegrable systems. We explain the relation between the two and in particular show that they coincide when transforming between second-order superintegrable systems. Unlike in the case of second-order superintegrability, the quantum analog of CCM has only been proven for a subclass of systems with integrals of a specific form. We give the proof and as an application show the mapping of a family of superintegrable deformations of the simple harmonic oscillator to an associated family of superintegrable deformations of the Kepler-Coulomb potential.

  17. Equation of state for magnetized Coulomb plasmas

    NASA Astrophysics Data System (ADS)

    Potekhin, A. Y.; Chabrier, G.

    2013-02-01

    We have developed an analytical equation of state (EOS) for magnetized fully-ionized plasmas that cover a wide range of temperatures and densities, from low-density classical plasmas to relativistic, quantum plasma conditions. This EOS directly applies to calculations of structure and evolution of strongly magnetized white dwarfs and neutron stars. We review available analytical and numerical results for thermodynamic functions of the nonmagnetized and magnetized Coulomb gases, liquids, and solids. We propose a new analytical expression for the free energy of solid Coulomb mixtures. Based on recent numerical results, we have constructed analytical approximations for the thermodynamic functions of harmonic Coulomb crystals in quantizing magnetic fields. The analytical description ensures a consistent evaluation of all astrophysically important thermodynamic functions based on the first, second, and mixed derivatives of the free energy. Our numerical code for calculation of thermodynamic functions based on these approximations has been made publicly available. Using this code, we calculate and discuss the effects of electron screening and magnetic quantization on the position of the melting point in a range of densities and magnetic fields relevant to white dwarfs and outer envelopes of neutron stars. We consider also the thermal and mechanical structure of a magnetar envelope and argue that it can have a frozen surface which covers the liquid ocean above the solid crust. The Fortran code that realizes the analytical approximations described in this paper is available at http://www.ioffe.ru/astro/EIP/ and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/550/A43

  18. Coulomb Repulsion in Miniature Ion Mobility Spectrometry

    SciTech Connect

    Xu, J.; Whitten, W.B.; Ramsey, J.M.

    1999-08-08

    We have undertaken a study of ion mobility resolution in a miniature ion mobility spectrometer with a drift channel 1.7 mm in diameter and 35 mm in length. The device attained a maximum resolution of 14 in separating ions of NO, O{sub 2}, and methyl iodine. The ions were generated by pulses from a frequency-quadrupled Nd:YAG laser. Broadening due to Coulomb repulsion was modeled theoretically and shown experimentally to have a major effect on the resolution of the miniature device.

  19. Coulomb field in a constant electromagnetic background

    NASA Astrophysics Data System (ADS)

    Adorno, T. C.; Gitman, D. M.; Shabad, A. E.

    2016-06-01

    Nonlinear Maxwell equations are written up to the third-power deviations from a constant-field background, valid within any local nonlinear electrodynamics including QED with a Euler-Heisenberg (EH) effective Lagrangian. The linear electric response to an imposed static finite-sized charge is found in the vacuum filled by an arbitrary combination of constant and homogeneous electric and magnetic fields. The modified Coulomb field and corrections to the total charge and to the charge density are given in terms of derivatives of the effective Lagrangian with respect to the field invariants. These are specialized for the EH Lagrangian.

  20. Spatio-temporal correlations in Coulomb clusters

    NASA Astrophysics Data System (ADS)

    Ash, Biswarup; Chakrabarti, J.; Ghosal, Amit

    2016-05-01

    The dynamical responses of Coulomb-interacting particles in two-dimensional nanoclusters are analyzed at different temperatures characterizing their solid- and liquid-like behavior. Depending on the trap symmetry, spatial correlations undergo slow, stretched exponential relaxations at long times, arising from spatially correlated motion in string-like paths. Such results stem from the combined effects of confinement and long-range repulsion, making the systems inherently heterogeneous. While particles in a “solid” flow produce dynamic heterogeneities, motion in “liquid” yields an unusually long tail in the distribution of particle displacements. A phenomenological model captures much of the subtleties of our numerical simulations.

  1. Negative Coulomb Drag in Double Bilayer Graphene.

    PubMed

    Li, J I A; Taniguchi, T; Watanabe, K; Hone, J; Levchenko, A; Dean, C R

    2016-07-22

    We report on an experimental measurement of Coulomb drag in a double quantum well structure consisting of bilayer-bilayer graphene, separated by few layer hexagonal boron nitride. At low temperatures and intermediate densities, a novel negative drag response with an inverse sign is observed, distinct from the momentum and energy drag mechanisms previously reported in double monolayer graphene. By varying the device aspect ratio, the negative drag component is suppressed and a response consistent with pure momentum drag is recovered. In the momentum drag dominated regime, excellent quantitative agreement with the density and temperature dependence predicted for double bilayer graphene is found. PMID:27494491

  2. Coulomb sum rule for {sup 4}He

    SciTech Connect

    J. Carlson; J. Jourdan; R. Schiavilla; I. Sick

    2002-10-01

    We determine the Coulomb sum for {sup 4}He using world data on {sup 4}He(e, e') and compare the results to calculations based on realistic interactions and including two-body components in the nuclear charge operator. We find good agreement between theory and experiment using free-nucleon form factors. The apparent reduction of the in-medium G{sub ep} implied by IA-interpretation of the L/T-ratios measured in {sup 4}He(e,e'p) and {sup 4}He([vec]e, e'p) is not confirmed.

  3. Interstitial integrals in the multiple-scattering model

    SciTech Connect

    Swanson, J.R.; Dill, D.

    1982-08-15

    We present an efficient method for the evaluation of integrals involving multiple-scattering wave functions over the interstitial region. Transformation of the multicenter interstitial wave functions to a single center representation followed by a geometric projection reduces the integrals to products of analytic angular integrals and numerical radial integrals. The projection function, which has the value 1 in the interstitial region and 0 elsewhere, has a closed-form partial-wave expansion. The method is tested by comparing its results with exact normalization and dipole integrals; the differences are 2% at worst and typically less than 1%. By providing an efficient means of calculating Coulomb integrals, the method allows treatment of electron correlations using a multiple scattering basis set.

  4. Automated ambient desorption-ionization platform for surface imaging integrated with a commercial Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Pól, Jaroslav; Vidová, Veronika; Kruppa, Gary; Kobliha, Václav; Novák, Petr; Lemr, Karel; Kotiaho, Tapio; Kostiainen, Risto; Havlícek, Vladimír; Volný, Michael

    2009-10-15

    A fully automated atmospheric pressure ionization platform has been built and coupled with a commercial high-resolution Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) instrument. The outstanding performance of this instrument allowed screening on the basis of exact masses in imaging mode. The main novel aspect was in the integration of the atmospheric pressure ionization imaging into the current software for matrix-assisted laser desorption ionization (MALDI) imaging, which allows the user of this commercial dual-source mass spectrometer to perform MALDI-MS and different ambient MS imaging from the same user interface and to utilize the same software tools. Desorption electrospray ionization (DESI) and desorption atmospheric pressure photoionization (DAPPI) were chosen to test the ambient surface imaging capabilities of this new ionization platform. Results of DESI imaging experiments performed on brain tissue sections are in agreement with previous MS imaging reports obtained by DESI imaging, but due to the high resolution and mass accuracy of the FTICR instrument it was possible to resolve several ions at the same nominal mass in the DESI-MS spectra of brain tissue. These isobaric interferences at low resolution are due to the overlap of ions from different lipid classes with different biological relevance. It was demonstrated that with the use of high-resolution MS fast imaging screening of lipids can be achieved without any preseparation steps. DAPPI, which is a relatively new and less developed ambient ionization technique compared to DESI, was used in imaging mode for the first time ever. It showed promise in imaging of phytocompounds from plant leaves, and selective ionization of a sterol lipid was achieved by DAPPI from a brain tissue sample. PMID:19761221

  5. Experiments on Structure and Trapping of Coulomb balls

    SciTech Connect

    Block, D.; Arp, O.; Piel, A.; Melzer, A.

    2006-10-18

    This paper gives a survey of recent experiments on Coulomb balls. Starting with typical observations to introduce the Coulomb ball experiment and its diagnostic potential, their structural properties are discussed. Further, the trapping mechanism for the dust is quantified to allow for a systematic comparison of experiment and simulations. Finally, the presented results focus on the question how screening influences the structural properties and how Coulomb balls and other strongly coupled systems are related.

  6. Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots.

    PubMed

    Keller, A J; Lim, J S; Sánchez, David; López, Rosa; Amasha, S; Katine, J A; Shtrikman, Hadas; Goldhaber-Gordon, D

    2016-08-01

    In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior. PMID:27541473

  7. Coulomb excitation of radioactive {sup 79}Pb

    SciTech Connect

    Lister, C.J.; Blumenthal, D.; Davids, C.N.

    1995-08-01

    The technical challenges expected in experiments with radioactive beams can already be explored by using ions produced in primary reactions. In addition, the re-excitation of these ions by Coulomb excitation allows a sensitive search for collective states that are well above the yrast line. We are building an experiment to study Coulomb excitation of radioactive ions which are separated from beam particles by the Fragment Mass Analyzer. An array of gamma detectors will be mounted at the focal plane to measure the gamma radiation following re-excitation. Five Compton-suppressed Ge detectors and five planar LEPS detectors will be used. The optimum experiment of this type appears to be the study of {sup 79}Rb following the {sup 24}Mg ({sup 58}Ni,3p) reaction. We calculate that about 5 x 10{sup 5} {sup 79}Rb nuclei/second will reach the excitation foil. This rubidium isotope was selected for study as it is strongly produced and is highly deformed, so easily re-excited. The use of a {sup 58}Ni re-excitation foil offers the best yields. After re-excitation the ions will be subsequently transported into a shielded beamdump to prevent the accumulation of activity.

  8. Improved Shell models for screened Coulomb balls

    NASA Astrophysics Data System (ADS)

    Bonitz, M.; Kaehlert, H.; Henning, C.; Baumgartner, H.; Filinov, A.

    2006-10-01

    Spherical Coulomb crystals in dusty plasmas [1] are well described by an isotropic Yukawa-type pair interaction and an external parabolic confinement as was shown by extensive molecular dynamics simulations [2]. A much simpler description is possible with analytical shell models which have been derived for Yukawas plasmas in [3,4]. Here we analyze improved Yukawa shell models which include correlations along the lines proposed for Coulomb crystals in [5]. The shell configurations are efficiently evaluated using a Monte Carlo procedure. [1] O. Arp, A. Piel and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004). [2] M. Bonitz, D. Block, O. Arp, V. Golunychiy, H. Baumgartner, P. Ludwig, A. Piel and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [3] H. Totsuji, C. Totsuji, T. Ogawa, and K. Tsuruta, Phys. Rev. E 71, 045401 (2005). [4] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E [5] W.D. Kraeft and M. Bonitz, J. Phys. Conf. Ser. 35, 94 (2006).

  9. Turbine blade cooling using Coulomb repulsion

    NASA Astrophysics Data System (ADS)

    Breidenthal, Robert; Colannino, Joseph; Dees, John; Goodson, David; Krichtafovitch, Igor; Prevo, Tracy

    2012-11-01

    Video photography and thermocouples reveal the effect of an electric field on the flow around a stationary, idealized turbine blade downstream of a combustor. The hot products of combustion naturally include positive ions. When the blade is an electrode and elevated to a positive potential, it tends to attract the free electrons and repel the positive ions. Due to their lower mass, the light electrons are rapidly swept toward the blade, while the positive ions are repelled. As they collide with the neutrals in the hot gas, the positive ions transfer their momentum so that a Coulomb body force is exerted on the hot gas. Cool, compressed air is injected out of the stationary blade near its leading edge to form a layer of film cooling. In contrast to the hot combustion products, the cool air is not ionized. At the interface between the hot gas and the cool air, the Coulomb repulsion force acts on the former but not the latter, analogous to gravity at a stratified interface. An effective Richardson number representing the ratio of potential to kinetic energy characterizes the topography of the interface. When the electric field is turned on, the repulsion of the hot gas from the idealized blade is evident in video recordings and thermocouple measurements.

  10. Integration of the simian virus 40 genome into cellular DNA in temperature-sensitive (N) and temperature-insensitive (A) transformants of 3T3 rat and Chinese hamster lung cells.

    PubMed Central

    Chepelinsky, A B; Seif, R; Martin, R G

    1980-01-01

    We studied the pattern of integration of the simian virus 40 (SV40) genome into the cellular DNA of N-transformants (temperature sensitive) and A-transformants (temperature insensitive) derived from 3T3-Fisher rat and Chinese hamster lung cells. The SV40 DNA was covalently linked to the cellular DNA in both types of transformants. In the rat cells, most N-transformants contained SV40 sequences integrated at a single site; most A-transformants contained SV40 sequences integrated at two to five sites. In the Chinese hamster cells, no significant correlation between the number of integration sites and the phenotype of the transformant was found; one of three integration sites were observed for both the N- and A-transformants. Single copies and tandem repeats of SV40 sequences were observed in A- and N-transformants derived from rat cells. A-transformants arise neither by amplification of the SV40 genome nor by integration at a unique site. Images PMID:6251267

  11. Coulomb crystallization in classical and quantum systems

    NASA Astrophysics Data System (ADS)

    Bonitz, Michael

    2007-11-01

    Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or α-particle crystals in dense matter

  12. An Integral View on Virgo and Field Dwarf Elliptical Galaxies: Late-Type Origin and Environmental Transformations

    NASA Astrophysics Data System (ADS)

    Rys, Agnieszka; Falcon-Barroso, J.; van de Ven, G.

    2013-01-01

    Dwarf elliptical galaxies (dEs) are the most common galaxy class in dense environments. They are also a surprisingly inhomogenous class, which has made it challenging both to relate different dE subtypes to each other, as well as place the whole class in the larger context of galaxy assembly and (trans)formation processes. Here we will show the effects of environmental evolution on Virgo Cluster and field dEs, presenting the first large-scale integral-field spectroscopic (SAURON) data for this galaxy class. Our sample consists of 12 galaxies and no two of them are alike. We find that the level of rotation is not tied to flattening; we observe kinematic twists; we discover large-scale kinematically-decoupled components; we see varying gradients in line-strength maps. This great variety of morphological, kinematic, and stellar population parameters supports the claim that dEs are defunct dwarf spiral/irregular galaxies and points to a formation scenario that allows for a stochastic shaping of galaxy properties. The combined influence of ram-pressure stripping and harassment fulfils this requirement, still, their exact impact is not yet understood. We thus further investigate the properties of our sample by performing a detailed comprehensive analysis of its kinematic, dynamical, and stellar population properties. We infer the total (dark and baryonic) matter distribution by fitting the observed stellar velocity and velocity dispersion with the solutions of the Jeans equations. We obtain 2D age, metallicity, and enrichment information from line-strength analysis. We then tie these results to the galaxies' intrinsic (i.e. deprojected) locations in the cluster with the use of surface-brightness fluctuation distances. This step is essential to providing unbiased correlations with the local environment density. We show that the dark matter fraction, unlike the level of rotational support, appears to correlate with the clustrocentric distance, and that our dwarfs have

  13. Spherical Calogero model with oscillator/Coulomb potential: Quantum case

    NASA Astrophysics Data System (ADS)

    Correa, Francisco; Hakobyan, Tigran; Lechtenfeld, Olaf; Nersessian, Armen

    2016-06-01

    We consider the quantum mechanics of Calogero models in an oscillator or Coulomb potential on the N -dimensional sphere. Their Hamiltonians are obtained by an appropriate Dunkl deformation of the oscillator/Coulomb system on the sphere and its restriction to (Coxeter reflection) symmetric wave functions. By the same method we also find the symmetry generators and compute their algebras.

  14. Known-to-Unknown Approach to Teach about Coulomb's Law

    ERIC Educational Resources Information Center

    Thamburaj, P. K.

    2007-01-01

    Analogies from life experiences help students understand various relationships presented in an introductory chemistry course. Coulomb's law is a complex relationship encountered in introductory general chemistry. A proper understanding of the relationships between the quantities involved in Coulomb's law is necessary in order for students to…

  15. Dynamical effects in the Coulomb expansion following nuclear fragmentation

    SciTech Connect

    Chung, K.C.; Donangelo, R.; Schechter, H.

    1987-09-01

    The effects of the Coulomb expansion on the fragment kinetic energy spectrum for a fragmentating hot nuclear system is investigated. In particular, /sup 12/C-fragment spectra are calculated and compared with those predicted by the uniform expansion approximation. The results indicate that the energy spectra of fragments are quite sensitive to the details of the Coulomb expansion treatment.

  16. Coulomb excitation of {sup 189}Os

    SciTech Connect

    Seale, W.A.; Botelho, S.; Ribas, R.V.

    1993-10-01

    The transitional nucleus {sup 189}Os has been studied by Coulomb excitation. Measurements with a Ge(HP) detector were made at 0{degrees}, 55{degrees}, 90{degrees} with beams of {sup 28}Si at 80 and 88 Me {sup 35}Cl at 80 MeV and {sup 16}O at 58 MeV. A total of gamma-ray transitions leading to 23 levels we used in the least-squares code GOSIA to determined reduced matrix elements. A theoretic understanding of this nucleus has been attempt from the point of view of current nuclear mode as they apply to systematics of the 1/2 {sup -}[510] 3/2 -[512], 1/2 [503] levels in this ma region.

  17. Coulomb blockade of spin-dependent shuttling

    NASA Astrophysics Data System (ADS)

    Park, Hee Chul; Kadigrobov, Anatoli M.; Shekhter, Robert I.; Jonson, M.

    2013-12-01

    We show that nanomechanical shuttling of single electrons may enable qualitatively new functionality if spin-polarized electrons are injected into a nanoelectromechanical single-electron tunneling (NEM-SET) device. This is due to the combined effects of spin-dependent electron tunneling and Coulomb blockade of tunneling, which are phenomena that occur in certain magnetic NEM-SET devices. Two effects are predicted to occur in such structures. The first is a reentrant shuttle instability, by which we mean the sequential appearance, disappearance and again the appearance of a shuttle instability as the driving voltage is increased (or the mechanical dissipation is diminished). The second effect is an enhanced spin polarization of the nanomechanically assisted current flow.

  18. Ion Coulomb Crystals and Their Applications

    NASA Astrophysics Data System (ADS)

    Drewsen, Michael

    The following text will give a brief introduction to the physics of the spatially ordered structures, so-called Coulomb crystals, that appear when confined ions are cooled to sufficiently low temperatures. It will as well briefly comment on the very diverse scientific applications of such crystals, which have emerged in the past two decades. While this document lacks figures and many specific references, it is the hope, not the text will stimulate the reader to dig deeper into one or more of the discussed subjects, and inspire her/him to think about new potential applications. A fully referenced journal article of essentially the same text can be found in Physica B 460, 105 (2015) [1].

  19. The ghost propagator in Coulomb gauge

    SciTech Connect

    Watson, P.; Reinhardt, H.

    2011-05-23

    We present results for a numerical study of the ghost propagator in Coulomb gauge whereby lattice results for the spatial gluon propagator are used as input to solving the ghost Dyson-Schwinger equation. We show that in order to solve completely, the ghost equation must be supplemented by a boundary condition (the value of the inverse ghost propagator dressing function at zero momentum) which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until 'forced' to freeze out in the infrared to the value of the boundary condition. The boundary condition can be interpreted in terms of the Gribov gauge-fixing ambiguity; we also demonstrate that this is not connected to the renormalization. Further, the connection to the temporal gluon propagator and the infrared slavery picture of confinement is discussed.

  20. Theoretical description of Coulomb balls: Fluid phase

    SciTech Connect

    Wrighton, J.; Dufty, J. W.; Kaehlert, H.; Bonitz, M.

    2009-12-15

    A theoretical description for the radial density profile of a finite number of identical charged particles confined in a harmonic trap is developed for application over a wide range of Coulomb coupling (or, equivalently, temperatures) and particle numbers. A simple mean-field approximation neglecting correlations yields a density profile which is monotonically decreasing with radius for all temperatures, in contrast to molecular dynamics simulations and experiments showing shell structure at lower temperatures. A more complete theoretical description including charge correlations is developed here by an extension of the hypernetted chain approximation, developed for bulk fluids, to the confined charges. The results reproduce all of the qualitative features observed in molecular dynamics simulations and experiments. These predictions are then tested quantitatively by comparison with benchmark Monte Carlo simulations. Quantitative accuracy of the theory is obtained by correcting the hypernetted chain approximation with a representation for the associated bridge functions.

  1. Supercurrent Drag via the Coulomb Interaction

    NASA Astrophysics Data System (ADS)

    Duan, Ji-Min; Yip, Sungkit

    1996-03-01

    We predict a supercurrent drag effect due to the Coulomb interaction between two parallel superconducting wires/layers. In contrast to previously explored frictional drag effect between two semiconducting quantum wells, our nondissipative drag mechanism ( J.-M. Duan and S. K. Yip, Phys. Rev. Lett.70), 3647 (1993). is based on considerations of the free energy of collective charge fluctuations. Our prediction has been confirmed experimentally ( X. Huang et al.), Phys. Rev. Lett.74, 4051 (1995). This mechanism generally exists in other nondissipative systems, such as double-layer quantum Hall syatems ( J.-M. Duan, Europhys. Lett.29), 489 (1995)., or between the two edge channels of a Hall bar, and between one-dimensional Luttinger Liquids.

  2. Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit

    NASA Astrophysics Data System (ADS)

    Gebremedhin, Daniel H.; Weatherford, Charles A.

    2014-05-01

    An efficient way of evolving a solution to an ordinary differential equation is presented. A finite element method is used where we expand in a convenient local basis set of functions that enforce both function and first derivative continuity across the boundaries of each element. We also implement an adaptive step-size choice for each element that is based on a Taylor series expansion. This algorithm is used to solve for the eigenpairs corresponding to the one-dimensional soft Coulomb potential, 1/√x2+β2 , which becomes numerically intractable (because of extreme stiffness) as the softening parameter (β) approaches zero. We are able to maintain near machine accuracy for β as low as β =10-8 using 16-digit precision calculations. Our numerical results provide insight into the controversial one-dimensional hydrogen atom, which is a limiting case of the soft Coulomb problem as β →0.

  3. Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap

    NASA Astrophysics Data System (ADS)

    Van Gorp, S.; Beck, M.; Breitenfeldt, M.; De Leebeeck, V.; Friedag, P.; Herlert, A.; Iitaka, T.; Mader, J.; Kozlov, V.; Roccia, S.; Soti, G.; Tandecki, M.; Traykov, E.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

    2011-05-01

    In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N2) with N the number of particles. Approximation methods exist already to reduce the computation time to O(NlogN), although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use.

  4. Determination of screened Coulomb repulsion energies in organic molecular crystals: A real space approach

    NASA Astrophysics Data System (ADS)

    Cano-Cortés, Laura; Dolfen, Andreas; Merino, Jaime; Koch, Erik

    2010-06-01

    We present a general method for determining screened Coulomb parameters in molecular assemblies, in particular organic molecular crystals. This allows us to calculate the interaction parameters used in a generalized Hubbard model description of correlated organic materials. In such a model only the electrons in levels close to the Fermi level are included explicitly, while the effect of all other electrons is included as a renormalization of the model parameters. For the Coulomb integrals this renormalization is mainly due to screening. For molecular materials we can split the screening into intra- and inter-molecular screening. Here we demonstrate how the inter-molecular screening can be calculated by modeling the molecules by distributed point-polarizabilities and solving the resulting self-consistent electrostatic screening problem in real space. For the example of the quasi one-dimensional molecular metal TTF-TCNQ we demonstrate that the method gives remarkably accurate results.

  5. "I'll Squeeze It In": Transforming Preservice Classroom Teachers' Perceptions toward Movement Integration in Schools

    ERIC Educational Resources Information Center

    Goh, Tan Leng; Hannon, James C.; Newton, Maria; Webster, Collin; Podlog, Leslie; Pillow, Wanda

    2013-01-01

    A program titled Physical Education Programming Infusion (PEPI) was incorporated into a required science methods course for preservice classroom teachers (PCTs). Using the transformative learning theory and the social ecological model, the authors examined changes in PCTs' personal health behaviors and perceived barriers toward movement…

  6. Analytical solution of the advection-diffusion transport equation using a change-of-variable and integral transform technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents a formal exact solution of the linear advection-diffusion transport equation with constant coefficients for both transient and steady-state regimes. A classical mathematical substitution transforms the original advection-diffusion equation into an exclusively diffusive equation. ...

  7. Investigation of Prospective Teachers' Information and Communication Technology Integration Practices in Terms of Transformative Learning Theory

    ERIC Educational Resources Information Center

    Sahin Izmirli, Özden; Kabakçi Yurdakul, Isil

    2014-01-01

    An examination of prospective teachers' information and communication technology (ICT) integration skills development in an undergraduate program indicated that the only course available to practice these skills was the teaching practice course. However, the practice and development of these ICT integration skills in the teaching practice…

  8. Case Study for Integration of an Oncology Clinical Site in a Semantic Interoperability Solution based on HL7 v3 and SNOMED-CT: Data Transformation Needs.

    PubMed

    Ibrahim, Ahmed; Bucur, Anca; Perez-Rey, David; Alonso, Enrique; de Hoog, Matthy; Dekker, Andre; Marshall, M Scott

    2015-01-01

    This paper describes the data transformation pipeline defined to support the integration of a new clinical site in a standards-based semantic interoperability environment. The available datasets combined structured and free-text patient data in Dutch, collected in the context of radiation therapy in several cancer types. Our approach aims at both efficiency and data quality. We combine custom-developed scripts, standard tools and manual validation by clinical and knowledge experts. We identified key challenges emerging from the several sources of heterogeneity in our case study (systems, language, data structure, clinical domain) and implemented solutions that we will further generalize for the integration of new sites. We conclude that the required effort for data transformation is manageable which supports the feasibility of our semantic interoperability solution. The achieved semantic interoperability will be leveraged for the deployment and evaluation at the clinical site of applications enabling secondary use of care data for research. This work has been funded by the European Commission through the INTEGRATE (FP7-ICT-2009-6-270253) and EURECA (FP7-ICT-2011-288048) projects. PMID:26306242

  9. Characterizing intra-exciton Coulomb scattering in terahertz excitations

    SciTech Connect

    Zybell, S.; Eßer, F.; Helm, M.; Bhattacharyya, J.; Winnerl, S.; Schneider, H.; Schneebeli, L.; Böttge, C. N.; Kira, M.; Koch, S. W.; Andrews, A. M.; Strasser, G.

    2014-11-17

    An intense terahertz field is applied to excite semiconductor quantum wells yielding strong non-equilibrium exciton distributions. Even though the relaxation channels involve a complicated quantum kinetics of Coulomb and phonon effects, distinct relaxation signatures of Coulomb scattering are identified within time-resolved photoluminescence by comparing the experiment with a reduced model that contains all relevant microscopic processes. The analysis uncovers a unique time scale for the Coulomb scattering directly from experiments and reveals the influence of phonon relaxation as well as radiative decay.

  10. Positron scattering from hydrogen atom with screened Coulomb potentials

    SciTech Connect

    Ghoshal, Arijit; Nayek, Sujay; Kamali, M. Z. M.; Ratnavelu, K.

    2014-03-05

    Elastic positron-hydrogen collisions with screened Coulomb potentials have been investigated using a second-order distorted wave Born approximation in the momentum space. Two types of potentials have been considered, namely, static screened Coulomb potential and exponential cosine-screened Coulomb potential. Using a simple variationally determined hydrogenic wave function it has been possible to obtain the scattering amplitude in a closed form. A detailed study has been made on the differential and total cross sections in the energy range 20–300 eV.

  11. Electron attraction mediated by Coulomb repulsion.

    PubMed

    Hamo, A; Benyamini, A; Shapir, I; Khivrich, I; Waissman, J; Kaasbjerg, K; Oreg, Y; von Oppen, F; Ilani, S

    2016-07-21

    One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed 'excitonic', promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the 'glue' that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter. PMID:27443742

  12. Accelerated Monte Carlo Methods for Coulomb Collisions

    NASA Astrophysics Data System (ADS)

    Rosin, Mark; Ricketson, Lee; Dimits, Andris; Caflisch, Russel; Cohen, Bruce

    2014-03-01

    We present a new highly efficient multi-level Monte Carlo (MLMC) simulation algorithm for Coulomb collisions in a plasma. The scheme, initially developed and used successfully for applications in financial mathematics, is applied here to kinetic plasmas for the first time. The method is based on a Langevin treatment of the Landau-Fokker-Planck equation and has a rich history derived from the works of Einstein and Chandrasekhar. The MLMC scheme successfully reduces the computational cost of achieving an RMS error ɛ in the numerical solution to collisional plasma problems from (ɛ-3) - for the standard state-of-the-art Langevin and binary collision algorithms - to a theoretically optimal (ɛ-2) scaling, when used in conjunction with an underlying Milstein discretization to the Langevin equation. In the test case presented here, the method accelerates simulations by factors of up to 100. We summarize the scheme, present some tricks for improving its efficiency yet further, and discuss the method's range of applicability. Work performed for US DOE by LLNL under contract DE-AC52- 07NA27344 and by UCLA under grant DE-FG02-05ER25710.

  13. Spatio-temporal correlations in Coulomb clusters

    NASA Astrophysics Data System (ADS)

    Ghosal, Amit; Ash, Biswarup; Chakrabarti, Jaydeb

    Dynamical response of Coulomb-particles in nanoclusters are investigated at different temperatures characterizing their solid-like (Wigner molecule) and liquid-like behavior. The density correlations probe spatio-temporal relaxation, uncovering distinct behavior at multiple time scales in these systems. They show a stretched-Gaussian or stretched-exponential spatial decay at long times in circular and irregular traps. Interplay of confinement and long-range nature of interactions yields spatially correlated motion of the particles in string-like paths, leaving the system heterogeneous even at long times. While particles in a `solid' flow producing dynamic heterogeneities, their random motion in `liquid' defies central limit theorem. Distinguishing the two confinements, temperature dependent motional signatures serve as a criterion for the crossover between `solid' and `liquid'. The irregular Wigner molecule turns into a nearly homogeneous liquid over a much wider temperature window compared to the circular case. The temperature dependence of different relaxation time scales builds crucial insights. A phenomenological model, relating the unusual dynamics to the heterogeneous nature of the diffusivities in the system, captures much of the subtleties of our numerical simulations.

  14. Multilevel Monte Carlo simulation of Coulomb collisions

    DOE PAGESBeta

    Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; Caflisch, R. E.; Cohen, B. I.

    2014-05-29

    We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε–2) or (ε–2(lnε)2), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε–3) for direct simulation Monte Carlo or binary collision methods.more » We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10–5. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.« less

  15. Multilevel Monte Carlo simulation of Coulomb collisions

    SciTech Connect

    Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; Caflisch, R. E.; Cohen, B. I.

    2014-05-29

    We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε–2) or (ε–2(lnε)2), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε–3) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10–5. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.

  16. Deep inelastic scattering near the Coulomb barrier

    SciTech Connect

    Gehring, J.; Back, B.; Chan, K.

    1995-08-01

    Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems {sup 124,112}Sn + {sup 58,64}Ni by Wolfs et al. We previously extended these measurements to the system {sup 136}Xe + {sup 64}Ni and currently measured the system {sup 124}Xe + {sup 58}Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring.

  17. Coulomb Collision Algorithms for Particle Codes

    NASA Astrophysics Data System (ADS)

    Cohen, Bruce

    2006-04-01

    This paper surveys some of the particle code algorithms used to model Coulomb collisions in fully ionized plasmas, e.g., pair-wise operators such as the Takizuka-Abe^1 scheme and extensions^2, Langevin equation collision operators^3,4, and partially linearized gyrokinetic collisions operators for strongly magnetized plasmas.^5,6,7 Some recent experience is reported.^8 Issues such as physics completeness, accuracy, and comparative algorithm performance are highlighted. 1. T. Takizuka and H. Abe, J. Comput. Phys. 25, 205 (1977). 2. K. Nanbu, Phys. Rev. E 55, 4642 (1997). 3. M.E. Jones, et al., J. Comp. Phys. 123, 169 (1996). 4. W.M. Manheimer, M. Lampe, and G. Joyce, et al., J. Comp. Phys. 138, 565 (1997). 5. X.Q. Xu and M.N. Rosenbluth, Phys. Fluids B 3, 627 (1991). 6. A.M. Dimits and B.I. Cohen, Phys. Rev. E 49, 709 (1994). 7. Z. Lin, W. M. Tang, and W. W. Lee, Phys.Plasmas 2, 2975 (August 1995). 8. B.I. Cohen, et al., ``Effects of ion-ion collisions and inhomogeneity in two-dimensional kinetic ion simulations of stimulated Brillouin backscattering,'' accepted for publication in Phys. Plasmas (2006).

  18. Electron attraction mediated by Coulomb repulsion

    NASA Astrophysics Data System (ADS)

    Hamo, A.; Benyamini, A.; Shapir, I.; Khivrich, I.; Waissman, J.; Kaasbjerg, K.; Oreg, Y.; von Oppen, F.; Ilani, S.

    2016-07-01

    One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed ‘excitonic’, promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the ‘glue’ that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter.

  19. Reply to "Comment on `Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit' "

    NASA Astrophysics Data System (ADS)

    Gebremedhin, Daniel H.; Weatherford, Charles A.

    2015-02-01

    This is a response to the comment we received on our recent paper "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit." In that paper, we introduced a computational algorithm that is appropriate for solving stiff initial value problems, and which we applied to the one-dimensional time-independent Schrödinger equation with a soft Coulomb potential. We solved for the eigenpairs using a shooting method and hence turned it into an initial value problem. In particular, we examined the behavior of the eigenpairs as the softening parameter approached zero (hard Coulomb limit). The commenters question the existence of the ground state of the hard Coulomb potential, which we inferred by extrapolation of the softening parameter to zero. A key distinction between the commenters' approach and ours is that they consider only the half-line while we considered the entire x axis. Based on mathematical considerations, the commenters consider only a vanishing solution function at the origin, and they question our conclusion that the ground state of the hard Coulomb potential exists. The ground state we inferred resembles a δ (x ) , and hence it cannot even be addressed based on their argument. For the excited states, there is agreement with the fact that the particle is always excluded from the origin. Our discussion with regard to the symmetry of the excited states is an extrapolation of the soft Coulomb case and is further explained herein.

  20. Symbolic programming language in molecular multicenter integral problem

    NASA Astrophysics Data System (ADS)

    Safouhi, Hassan; Bouferguene, Ahmed

    It is well known that in any ab initio molecular orbital (MO) calculation, the major task involves the computation of molecular integrals, among which the computation of three-center nuclear attraction and Coulomb integrals is the most frequently encountered. As the molecular system becomes larger, computation of these integrals becomes one of the most laborious and time-consuming steps in molecular systems calculation. Improvement of the computational methods of molecular integrals would be indispensable to further development in computational studies of large molecular systems. To develop fast and accurate algorithms for the numerical evaluation of these integrals over B functions, we used nonlinear transformations for improving convergence of highly oscillatory integrals. These methods form the basis of new methods for solving various problems that were unsolvable otherwise and have many applications as well. To apply these nonlinear transformations, the integrands should satisfy linear differential equations with coefficients having asymptotic power series in the sense of Poincaré, which in their turn should satisfy some limit conditions. These differential equations are very difficult to obtain explicitly. In the case of molecular integrals, we used a symbolic programming language (MAPLE) to demonstrate that all the conditions required to apply these nonlinear transformation methods are satisfied. Differential equations are obtained explicitly, allowing us to demonstrate that the limit conditions are also satisfied.

  1. A modified Bessel-type integral transform and its compositions with fractional calculus operators on spaces and

    NASA Astrophysics Data System (ADS)

    Glaeske, H.-J.; Kilbas, Anatoly A.; Saigo, Megumi

    2000-06-01

    The paper is devoted to study the integral transformwith the kernelfor [beta]>0; Re([gamma])>1/[beta]-1; ; Re(z)>0, which is a generalization of the modified Bessel function of the third kind or Macdonald function K-[gamma](z). Properties of [lambda][gamma],[sigma]([beta])(z) are investigated and compositions of the operator L[gamma],[sigma]([beta]) with the left- and right-sided Liouville fractional integrals and derivatives are proved.

  2. Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots

    NASA Astrophysics Data System (ADS)

    Ardelt, P.-L.; Gawarecki, K.; Müller, K.; Waeber, A. M.; Bechtold, A.; Oberhofer, K.; Daniels, J. M.; Klotz, F.; Bichler, M.; Kuhn, T.; Krenner, H. J.; Machnikowski, P.; Finley, J. J.

    2016-02-01

    We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k .p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.

  3. Thermodynamic properties of the magnetized Coulomb crystal lattices

    NASA Astrophysics Data System (ADS)

    Kozhberov, A. A.

    2016-08-01

    It is thought that Coulomb crystals of ions with hexagonal close-packed lattice may form in the crust of strongly-magnetized neutron stars (magnetars). In this work we are trying to verify this prediction assuming that the direction of the magnetic field corresponds to the minimum of the zero-point energy. We also continue a detailed study of vibration modes and thermodynamic properties of magnetized Coulomb crystals in a wide range of temperatures and magnetic fields. It is demonstrated that the total Helmholtz free energy of the body-centered cubic Coulomb crystal is always lower than that of the Coulomb crystal with hexagonal close-packed or face-centered cubic lattice, which casts doubt on the hypothesis above.

  4. Correlated Coulomb Drag in Capacitively Coupled Quantum-Dot Structures.

    PubMed

    Kaasbjerg, Kristen; Jauho, Antti-Pekka

    2016-05-13

    We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs)-a bias-driven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach that accounts for higher-order tunneling (cotunneling) processes as well as energy-dependent lead couplings, and identify a mesoscopic Coulomb drag mechanism driven by nonlocal multielectron cotunneling processes. Our theory establishes the conditions for a nonzero drag as well as the direction of the drag current in terms of microscopic system parameters. Interestingly, the direction of the drag current is not determined by the drive current, but by an interplay between the energy-dependent lead couplings. Studying the drag mechanism in a graphene-based CQD heterostructure, we show that the predictions of our theory are consistent with recent experiments on Coulomb drag in CQD systems. PMID:27232031

  5. The generalized Coulomb interactions for relativistic scalar bosons

    NASA Astrophysics Data System (ADS)

    Zarrinkamar, S.; Panahi, H.; Rezaei, M.

    2016-07-01

    Approximate analytical solutions of Duffin-Kemmer-Petiau (DKP) equation are obtained for the truncated Coulomb, generalized Cornell, Richardson and Song-Lin potentials via the quasi-exact analytical ansatz approach.

  6. Correlated Coulomb Drag in Capacitively Coupled Quantum-Dot Structures

    NASA Astrophysics Data System (ADS)

    Kaasbjerg, Kristen; Jauho, Antti-Pekka

    2016-05-01

    We study theoretically Coulomb drag in capacitively coupled quantum dots (CQDs)—a bias-driven dot coupled to an unbiased dot where transport is due to Coulomb mediated energy transfer drag. To this end, we introduce a master-equation approach that accounts for higher-order tunneling (cotunneling) processes as well as energy-dependent lead couplings, and identify a mesoscopic Coulomb drag mechanism driven by nonlocal multielectron cotunneling processes. Our theory establishes the conditions for a nonzero drag as well as the direction of the drag current in terms of microscopic system parameters. Interestingly, the direction of the drag current is not determined by the drive current, but by an interplay between the energy-dependent lead couplings. Studying the drag mechanism in a graphene-based CQD heterostructure, we show that the predictions of our theory are consistent with recent experiments on Coulomb drag in CQD systems.

  7. A New Hybrid STEP/Coulomb model for Aftershock Forecasting

    NASA Astrophysics Data System (ADS)

    Steacy, S.; Jimenez, A.; Gerstenberger, M.

    2014-12-01

    Aftershock forecasting models tend to fall into two classes - purely statistical approaches based on clustering, b-value, and the Omori-Utsu law; and Coulomb rate-state models which relate the forecast increase in rate to the magnitude of the Coulomb stress change. Recently, hybrid models combining physical and statistical forecasts have begun to be developed, for example by Bach and Hainzl (2012) and Steacy et al. (2013). The latter approach combined Coulomb stress patterns with the STEP (short-term earthquake probability) model by redistributing expected rate from areas with decreased stress to regions where the stress had increased. The chosen 'Coulomb Redistribution Parameter' (CRP) was 0.93, based on California earthquakes, which meant that 93% of the total rate was expected to occur where the stress had increased. The model was tested against the Canterbury sequence and the main result was that the new model performed at least as well as, and often better than, STEP when tested against retrospective data but that STEP was generally better in pseudo-prospective tests that involved data actually available within the first 10 days of each event of interest. The authors suggested that the major reason for this discrepancy was uncertainty in the slip models and, particularly, in the geometries of the faults involved in each complex major event. Here we develop a variant of the STEP/Coulomb model in which the CRP varies based on the percentage of aftershocks that occur in the positively stressed areas during the forecast learning period. We find that this variant significantly outperforms both STEP and the previous hybrid model in almost all cases, even when the input Coulomb model is quite poor. Our results suggest that this approach might be more useful than Coulomb rate-state when the underlying slip model is not well constrained due to the dependence of that method on the magnitude of the Coulomb stress change.

  8. Diffusion and Coulomb separation of ions in dense matter.

    PubMed

    Beznogov, M V; Yakovlev, D G

    2013-10-18

    We analyze diffusion equations in strongly coupled Coulomb mixtures of ions in dense stellar matter. Strong coupling of ions in the presence of gravitational forces and electric fields (induced by plasma polarization in the presence of gravity) produces a specific diffusion current which can separate ions with the same A/Z (mass to charge number) ratios but different Z. This Coulomb separation of ions can be important for the evolution of white dwarfs and neutron stars. PMID:24182248

  9. Renormalization in Coulomb-gauge QCD within the Lagrangian formalism

    SciTech Connect

    Niegawa, A.

    2006-08-15

    We study renormalization of Coulomb-gauge QCD within the Lagrangian, second-order, formalism. We derive a Ward identity and the Zinn-Justin equation, and, with the help of the latter, we give a proof of algebraic renormalizability of the theory. Through diagrammatic analysis, we show that, in the strict Coulomb gauge, g{sup 2}D{sup 00} is invariant under renormalization. (D{sup 00} is the time-time component of the gluon propagator.)

  10. Analysis and results of the 104Sn Coulomb excitation experiment

    NASA Astrophysics Data System (ADS)

    Guastalla, G.; DiJulio, D. D.; Górska, M.; Cederkäll, J.; Boutachkov, P.; Golubev, P.; Pietri, S.; Grawe, H.; Nowacki, F.; Algora, A.; Ameil, F.; Arici, T.; Atac, A.; Bentley, M. A.; Blazhev, A.; Bloor, D.; Brambilla, S.; Braun, N.; Camera, F.; Domingo Pardo, C.; Estrade, A.; Farinon, F.; Gerl, J.; Goel, N.; Grȩbosz, J.; Habermann, T.; Hoischen, R.; Jansson, K.; Jolie, J.; Jungclaus, A.; Kojouharov, I.; Knoebel, R.; Kumar, R.; Kurcewicz, J.; Kurz, N.; Lalović, N.; Merchan, E.; Moschner, K.; Naqvi, F.; Nara Singh, B. S.; Nyberg, J.; Nociforo, C.; Obertelli, A.; Pfützner, M.; Pietralla, N.; Podolyák, Z.; Prochazka, A.; Ralet, D.; Reiter, P.; Rudolph, D.; Schaffner, H.; Schirru, F.; Scruton, L.; Swaleh, T.; Taprogge, J.; Wadsworth, R.; Warr, N.; Weick, H.; Wendt, A.; Wieland, O.; Winfield, J. S.; Wollersheim, H. J.

    2014-09-01

    The analysis of the Coulomb excitation experiment conducted on 104Sn required a strict selection of the data in order to reduce the large background present in the γ-ray energy spectra and identify the γ-ray peak corresponding to the Coulomb excitation events. As a result the B(E2; 0+ → 2+) value could be extracted, which established the downward trend towards 100Sn and therefore the robustness of the N=Z=50 core against quadrupole excitations.

  11. Diffusion and Coulomb Separation of Ions in Dense Matter

    NASA Astrophysics Data System (ADS)

    Beznogov, M. V.; Yakovlev, D. G.

    2013-10-01

    We analyze diffusion equations in strongly coupled Coulomb mixtures of ions in dense stellar matter. Strong coupling of ions in the presence of gravitational forces and electric fields (induced by plasma polarization in the presence of gravity) produces a specific diffusion current which can separate ions with the same A/Z (mass to charge number) ratios but different Z. This Coulomb separation of ions can be important for the evolution of white dwarfs and neutron stars.

  12. Coulomb's Law Modification in Nonlinear and in Noncommutative Electrodynamics

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Schmidt, Iván

    We study the lowest-order modifications of the static potential for Born-Infeld electrodynamics and for the θ-expanded version of the noncommutative U(1) gauge theory, within the framework of the gauge-invariant but path-dependent variables formalism. The calculation shows a long-range correction (1/r5-type) to the Coulomb potential in Born-Infeld electrodynamics. However, the Coulomb nature of the potential (to order e2) is preserved in noncommutative electrodynamics.

  13. Symplectic wavelet transformation.

    PubMed

    Fan, Hong-Yi; Lu, Hai-Liang

    2006-12-01

    Usually a wavelet transform is based on dilated-translated wavelets. We propose a symplectic-transformed-translated wavelet family psi(*)(r,s)(z-kappa) (r,s are the symplectic transform parameters, |s|(2)-|r|(2)=1, kappa is a translation parameter) generated from the mother wavelet psi and the corresponding wavelet transformation W(psi)f(r,s;kappa)=integral(infinity)(-infinity)(d(2)z/pi)f(z)psi(*)(r,s)(z-kappa). This new transform possesses well-behaved properties and is related to the optical Fresnel transform in quantum mechanical version. PMID:17099740

  14. Aftershock triggering by complete Coulomb stress changes

    USGS Publications Warehouse

    Kilb, Debi; Gomberg, J.; Bodin, P.

    2002-01-01

    We examine the correlation between seismicity rate change following the 1992, M7.3, Landers, California, earthquake and characteristics of the complete Coulomb failure stress (CFS) changes (??CFS(t)) that this earthquake generated. At close distances the time-varying "dynamic" portion of the stress change depends on how the rupture develops temporally and spatially and arises from radiated seismic waves and from permanent coseismic fault displacement. The permanent "static" portion (??CFS) depends only on the final coseismic displacement. ??CFS diminishes much more rapidly with distance than the transient, dynamic stress changes. A common interpretation of the strong correlation between ??CFS and aftershocks is that load changes can advance or delay failure. Stress changes may also promote failure by physically altering properties of the fault or its environs. Because it is transient, ??CFS(t) can alter the failure rate only by the latter means. We calculate both ??CFS and the maximum positive value of ??CFS(t) (peak ??CFS(t)) using a reflectivity program. Input parameters are constrained by modeling Landers displacement seismograms. We quantify the correlation between maps of seismicity rate changes and maps of modeled ??CFS and peak ??CFS(t) and find agreement for both models. However, rupture directivity, which does not affect ??CFS, creates larger peak ??CFS(t) values northwest of the main shock. This asymmetry is also observed in seismicity rate changes but not in ??CFS. This result implies that dynamic stress changes are as effective as static stress changes in triggering aftershocks and may trigger earthquakes long after the waves have passed.

  15. Efros-Shklovskii variable range hopping conductivity without Coulomb gap

    NASA Astrophysics Data System (ADS)

    Chen, Tianran; Skinner, Brian

    In doped semiconductors and Coulomb glasses, in the limit of weak coupling, the electron conductivity primarily proceeds by phonon-assisted tunneling or hopping between different sites through the insulating gaps that separate them. Electron conduction can occur both through nearest-neighbor hopping and through cotunneling of electrons between distant sites via a chain of intermediate virtual states. In the presence of some disorder, the latter mechanism dominates at low temperatures, where the length of the hops grows to optimize the conductivity. This transport mechanism was introduced by Mott, and is called variable range hopping. When the Coulomb interaction between localized electrons is taken into account, it can be shown that at a sufficiently low temperature, variable range hopping conductivity obeys the Efros-Shklovskii (ES) law, which has been observed in a number of amorphous semiconductors and granular metal systems at low temperatures. ES conductivity has been long understood as the result of a soft, Coulomb gap at the Fermi level. However, such a theory overlooks the presence of spatial correlations between site energies and their possible effects on electrical conductivity. In this talk, we show both analytically and numerically that in systems where spatial correlations must be taken into account, ES conductivity may persist far outside the Coulomb gap, in contrast to conventional transport theory for doped semiconductors and Coulomb glasses where ES conductivity only occurs within the Coulomb gap.

  16. The One-Dimensional Soft-Coulomb Problem and the Hard-Coulomb Limit

    NASA Astrophysics Data System (ADS)

    Weatherford, Charles; Gebremedhin, Daniel

    2014-05-01

    A new and efficient way of evolving a solution to an ordinary differential equation is presented. A finite element method is used where we expand in a convenient local basis set of functions that enforce both function and first derivative continuity across the boundary. We also, for the first time, implement an adaptive step size choice for each element that is based on a Taylor series expansion. This algorithm is used to solve for the eigenpairs corresponding to the one-dimensional soft Coulomb potential, 1 /√{x2 +β2 } , which becomes numerically intractable as the softening parameter (β) approaches zero. We are able to maintain near machine accuracy for β as low as β =10-8 using 16 digit precision calculations. Our numerical results provide a new insight into the controversial one dimensional Hydrogen atom which is a limiting case of the soft Coulomb problem as β --> 0 . CAW was supported by the Defense Threat Reduction Agency, and CAW and DG were both supported by the National Nuclear Security Agency.

  17. Lower bound on the coefficient of an exchangelike energy for a single bound electron in a screened Coulomb potential

    SciTech Connect

    Nagy, I.

    2011-04-15

    The spurious self-interaction energy, which is one-half the integrated electrostatic interaction energy of a normalized electronic charge distribution with the potential field generated by itself, is calculated analytically for a 1s-like electron charge distribution governed by an attractive screened Hulthen-type model potential. The exact result obtained is used, via an energetic cancellation constraint and a convenient Hoelder's integral inequality, to deduce an analytical lower bound for the screening-dependent positive coefficient of a negative exchange-like energy term applied routinely in the local-density approximation to density functional theory with Coulomb potentials. The bare Coulomb case is investigated by Sobolev's integral inequality as well.

  18. Integrative Network Analysis Combined with Quantitative Phosphoproteomics Reveals Transforming Growth Factor-beta Receptor type-2 (TGFBR2) as a Novel Regulator of Glioblastoma Stem Cell Properties.

    PubMed

    Narushima, Yuta; Kozuka-Hata, Hiroko; Koyama-Nasu, Ryo; Tsumoto, Kouhei; Inoue, Jun-ichiro; Akiyama, Tetsu; Oyama, Masaaki

    2016-03-01

    Glioblastoma is one of the most malignant brain tumors with poor prognosis and their development and progression are known to be driven by glioblastoma stem cells. Although glioblastoma stem cells lose their cancer stem cell properties during cultivation in serum-containing medium, little is known about the molecular mechanisms regulating signaling alteration in relation to reduction of stem cell-like characteristics. To elucidate the global phosphorylation-related signaling events, we performed a SILAC-based quantitative phosphoproteome analysis of serum-induced dynamics in glioblastoma stem cells established from the tumor tissues of the patient. Among a total of 2876 phosphorylation sites on 1584 proteins identified in our analysis, 732 phosphorylation sites on 419 proteins were regulated through the alteration of stem cell-like characteristics. The integrative computational analyses based on the quantified phosphoproteome data revealed the relevant changes of phosphorylation levels regarding the proteins associated with cytoskeleton reorganization such as Rho family GTPase and Intermediate filament signaling, in addition to transforming growth factor-β receptor type-2 (TGFBR2) as a prominent upstream regulator involved in the serum-induced phosphoproteome regulation. The functional association of transforming growth factor-β receptor type-2 with stem cell-like properties was experimentally validated through signaling perturbation using the corresponding inhibitors, which indicated that transforming growth factor-β receptor type-2 could play an important role as a novel cell fate determinant in glioblastoma stem cell regulation. PMID:26670566

  19. Pathway of FeEDTA transformation and its impact on performance of NOx removal in a chemical absorption-biological reduction integrated process

    PubMed Central

    Li, Wei; Zhao, Jingkai; Zhang, Lei; Xia, Yinfeng; Liu, Nan; Li, Sujing; Zhang, Shihan

    2016-01-01

    A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation was investigated to assess its impact on the NOx removal in a biofilter. Experimental results revealed that the FeEDTA transformation involved iron precipitation and EDTA degradation. X-ray photoelectron spectroscopy analysis confirmed the iron was precipitated in the form of Fe(OH)3. The iron mass balance analysis showed 44.2% of the added iron was precipitated. The EDTA degradation facilitated the iron precipitation. Besides chemical oxidation, EDTA biodegradation occurred in the biofilter. The addition of extra EDTA helped recover the iron from the precipitation. The transformation of FeEDTA did not retard the NO removal. In addition, EDTA rather than the iron concentration determined the NO removal efficiency. PMID:26743930

  20. Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells

    SciTech Connect

    Mycek, M.A. |

    1995-12-01

    The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.

  1. Pleasure, Throwing Breaches, and Embodied Metaphors: Tracing Transformations-in-Participation for a Child With Autism to a Sensory Integration-Based Therapy Session.

    PubMed

    Park, Melissa

    2012-01-01

    In occupational therapy practice, the rich interweaving of procedural and narrative reasoning results in healing transformations. However, a lack of research focus on transformational processes perpetuates a focus on observable and measurable behaviors. In line with the movement toward evidence-based implementation research, this article focuses on a case study drawn from an ethnography of therapist-child-family interactions in a sensory integration-based clinic to provide a thick description of the moments leading up to and following changes in bodily and social engagement for a child with autism. Using theoretical resources on acted narratives and aesthetics, this article provides a developing method and language to show how an occupational therapist and a child with autism throw breaches to jointly create embodied metaphors of what matters to the child in his or her everyday life. A microanalysis of therapist-child bodily and sensing interactions also reveals how narrative and procedural reasoning converge in moments of pleasure that ultimately lead to outcomes in participation outside the clinic and confound characterizations of autistic aloneness. Implications for research on sensory integration approaches in general and social interventions for children with autism are discussed. PMID:24650787

  2. Building extraction from high-resolution optical spaceborne images using the integration of support vector machine (SVM) classification, Hough transformation and perceptual grouping

    NASA Astrophysics Data System (ADS)

    Turker, Mustafa; Koc-San, Dilek

    2015-02-01

    This paper presents an integrated approach for the automatic extraction of rectangular- and circular-shape buildings from high-resolution optical spaceborne images using the integration of support vector machine (SVM) classification, Hough transformation and perceptual grouping. The building patches are detected from the image using the binary SVM classification. The generated normalized digital surface model (nDSM) and the normalized difference vegetation index (NDVI) are incorporated in the classification process as additional bands. After detecting the building patches, the building boundaries are extracted through sequential processing of edge detection, Hough transformation and perceptual grouping. Those areas that are classified as building are masked and further processing operations are performed on the masked areas only. The edges of the buildings are detected through an edge detection algorithm that generates a binary edge image of the building patches. These edges are then converted into vector form through Hough transform and the buildings are constructed by means of perceptual grouping. To validate the developed method, experiments were conducted on pan-sharpened and panchromatic Ikonos imagery, covering the selected test areas in Batikent district of Ankara, Turkey. For the test areas that contain industrial buildings, the average building detection percentage (BDP) and quality percentage (QP) values were computed to be 93.45% and 79.51%, respectively. For the test areas that contain residential rectangular-shape buildings, the average BDP and QP values were computed to be 95.34% and 79.05%, respectively. For the test areas that contain residential circular-shape buildings, the average BDP and QP values were found to be 78.74% and 66.81%, respectively.

  3. Coulomb stress transfer and tectonic loading preceding the 2002 Denali fault earthquake

    USGS Publications Warehouse

    Bufe, C.G.

    2006-01-01

    Pre-2002 tectonic loading and Coulomb stress transfer are modeled along the rupture zone of the M 7.9 Denali fault earthquake (DFE) and on adjacent segments of the right-lateral Denali-Totschunda fault system in central Alaska, using a three-dimensional boundary-element program. The segments modeled closely follow, for about 95??, the arc of a circle of radius 375 km centered on an inferred asperity near the northeastern end of the intersection of the Patton Bay fault with the Alaskan megathrust under Prince William Sound. The loading model includes slip of 6 mm/yr below 12 km along the fault system, consistent with rotation of the Wrangell block about the asperity at a rate of about 1??/m.y. as well as slip of the Pacific plate at 5 cm/yr at depth along the Fairweather-Queen Charlotte transform fault system and on the Alaska megathrust. The model is consistent with most available pre-2002 Global Positioning System (GPS) displacement rate data. Coulomb stresses induced on the Denali-Totschunda fault system (locked above 12 km) by slip at depth and by transfer from the M 9.2 Prince William Sound earthquake of 1964 dominated the changing Coulomb stress distribution along the fault. The combination of loading (???70-85%) and coseismic stress transfer from the great 1964 earthquake (???15-30%) were the principal post-1900 stress factors building toward strike-slip failure of the northern Denali and Totschunda segments in the M 7.9 earthquake of November 2002. Postseismic stresses transferred from the 1964 earthquake may also have been a significant factor. The M 7.2-7.4 Delta River earthquake of 1912 (Carver et al., 2004) may have delayed or advanced the timing of the DFE, depending on the details and location of its rupture. The initial subevent of the 2002 DFE earthquake was on the 40-km Susitna Glacier thrust fault at the western end of the Denali fault rupture. The Coulomb stress transferred from the 1964 earthquake moved the Susitna Glacier thrust fault uniformly

  4. Inorganic nitrogen transformations in the bed of the Shingobee River, Minnesota: Integrating hydrologic and biological processes using sediment perfusion cores

    USGS Publications Warehouse

    Sheibley, R.W.; Duff, J.H.; Jackman, A.P.; Triska, F.J.

    2003-01-01

    Inorganic N transformations were examined in streambed sediments from the Shingobee River using sediment perfusion cores. The experimental design simulated groundwater-stream water mixing within sediment cores, which provided a well-defined one-dimensional representation of in situ hydrologic conditions. Two distinct hydrologic and chemical settings were preserved in the sediment cores: the lowermost sediments, perfused with groundwater, remained anaerobic during the incubations, whereas the uppermost sediments, perfused with oxic water pumped from the overlying water column, simulated stream water penetration into the bed. The maintenance of oxic and anoxic zones formed a biologically active aerobic-anaerobic interface. Ammonium (NH4+) dissolved in groundwater was transported conservatively through the lower core zone but was removed as it mixed with aerated recycle water. Concurrently, a small quantity of nitrate (NO3-) equaling ???25% of the NH4+ loss was produced in the upper sediments. The NH4+ and NO3- profiles in the uppermost sediments resulted from coupled nitrification-denitrification, because assimilation and sorption were negligible. We hypothesize that anaerobic microsites within the aerated upper sediments supported denitrification. Rates of nitrification and denitrification in the perfusion cores ranged 42-209 and 53-160 mg N m-2 day-1, respectively. The use of modified perfusion cores permitted the identification and quantification of N transformations and verified process control by surface water exchange into the shallow hyporheic zone of the Shingobee River.

  5. Integration of airborne Thematic Mapper Simulator (TMS) data and digitized aerial photography via an ISH transformation. [Intensity Saturation Hue

    NASA Technical Reports Server (NTRS)

    Ambrosia, Vincent G.; Myers, Jeffrey S.; Ekstrand, Robert E.; Fitzgerald, Michael T.

    1991-01-01

    A simple method for enhancing the spatial and spectral resolution of disparate data sets is presented. Two data sets, digitized aerial photography at a nominal spatial resolution 3,7 meters and TMS digital data at 24.6 meters, were coregistered through a bilinear interpolation to solve the problem of blocky pixel groups resulting from rectification expansion. The two data sets were then subjected to intensity-saturation-hue (ISH) transformations in order to 'blend' the high-spatial-resolution (3.7 m) digitized RC-10 photography with the high spectral (12-bands) and lower spatial (24.6 m) resolution TMS digital data. The resultant merged products make it possible to perform large-scale mapping, ease photointerpretation, and can be derived for any of the 12 available TMS spectral bands.

  6. Computation of the high temperature Coulomb density matrix in periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Militzer, B.

    2016-07-01

    The high temperature many-body density matrix is fundamental to path integral computation. The pair approximation, where the interaction part is written as a product of pair density matrices, is commonly used and is accurate to order τ2, where τ is the step size in the imaginary time. Here we present a method for systems with Coulomb interactions in periodic boundary conditions that consistently treats the all interactions with the same level of accuracy. It is shown that this leads to a more accurate high temperature solution of the Bloch equation. The method is applied to many-body simulation and tests for the isolated hydrogen atom and molecule are presented.

  7. The OpenMI - its Transformation From a Research Output to a Global Standard for the Integrated Modelling Community

    NASA Astrophysics Data System (ADS)

    Moore, R.

    2008-12-01

    The pressure to take a more integrated approach both to science and to management increases by the day. At almost any scale from local to global, it is no longer possible to consider issues in isolation; to do so runs a high risk of creating more problems than are solved. The consequence of this situation is that there is strong encouragement in the scientific world not just to understand and to be able to predict the response of individual processes but also to predict how those processes will interact. The manager is similarly encouraged to think in the widest terms about the likely impact of any policy before it is implemented. A new reservoir may solve a water supply problem but will it adversely affect the fishing and hence the tourist trade? How will climate change impact biodiversity? Will the drugs for treating a flu pandemic adversely affect river water quality? One approach to predicting such impacts would be to create new models simulating more and more processes. This, however, is neither feasible nor useful and makes poor use of the huge investment in existing models. A better approach, with many additional benefits, would be to find a way of linking existing models and modelling components such as databases or visualisation systems. Against this background, the European Commission, as part of its research programme to facilitate the introduction of integrated water management, commissioned a community project to find a generic solution to the linking of simulation models at run time. The outcome of this work was the Open Modelling Interface (OpenMI) standard and the creation of the OpenMI Association, an open, non-proprietary, not-for-profit, international organisation for its support. The work has received widespread recognition and encouragement from across the world, especially in the USA. A second phase is now building a community to continue the OpenMI's development and promote its use. The community's vision, mission and implementation strategy

  8. Reconfiguration of a Nadir-Pointing 2-Craft Coulomb Tether

    NASA Astrophysics Data System (ADS)

    Natarajan, A.; Schaub, H.; Parker, G. G.

    The linear dynamics and stability analysis of reconfiguring a 2-spacecraft Coulomb tether formation is investigated. In this concept the tether between two craft is replaced with electrostatic force fields. Here the relative distance between the two satellites is increased or decreased using electrostatic Coulomb forces. The two craft are connected by an electrostatic tether which is capable of both tensile and compressive forces. The resulting virtual structure can change its shape by modifying the desired reference length. As a result, the two-craft formation will essentially act as a long, slender, nearly-rigid body of variable length. Inter-spacecraft Coulomb forces cannot influence the inertial angular momentum of this formation. However, the gravity gradient effect can be exploited to stabilize the attitude of this Coulomb tether formation about an orbit radial direction. Limits of the Coulomb tether expansion and contraction rates are discussed using linearized time-varying dynamical models. These allow the reference length time histories to be designed while ensuring linear stability of the virtual structure.

  9. Coulomb versus physical string tension on the lattice

    NASA Astrophysics Data System (ADS)

    Burgio, Giuseppe; Quandt, Markus; Reinhardt, Hugo; Vogt, Hannes

    2015-08-01

    From continuum studies it is known that the Coulomb string tension σC gives an upper bound for the physical (Wilson) string tension σW [D. Zwanziger, Phys. Rev. Lett. 90, 102001 (2003)]. How does such a relationship translate to the lattice, however? In this paper we give evidence that on the lattice, while the two string tensions are related at zero temperature, they decouple at finite temperature. More precisely, we show that on the lattice the Coulomb gauge confinement scenario is always tied to the spatial string tension, which is known to survive the deconfinement phase transition and to cause screening effects in the quark-gluon plasma. Our analysis is based on the identification and elimination of center vortices, which allows us to control the physical string tension and study its effect on the Coulomb gauge observables. We also show how alternative definitions of the Coulomb potential may sense the deconfinement transition; however, a true static Coulomb gauge order parameter for the phase transition is still elusive on the lattice.

  10. Coulomb excitation studies of shape coexistence in atomic nuclei

    NASA Astrophysics Data System (ADS)

    Görgen, Andreas; Korten, Wolfram

    2016-02-01

    Low-energy Coulomb excitation provides a well-understood means of exciting atomic nuclei and allows measuring electromagnetic moments that can be directly related to the nuclear shape. The availability of radioactive ion beams (RIBs) at energies near the Coulomb barrier has made it possible to study shape coexistence in a variety of short-lived exotic nuclei. This review presents a short overview of the methods related to multi-step Coulomb excitation experiments, followed by a discussion of several examples. The focus is on two mass regions where recent Coulomb excitation experiments have contributed to the quantitative understanding of shape coexistence: nuclei with mass A≈ 70 near the N = Z line and nuclei with A ≈ 100 near neutron number N = 60. Experimental results are summarized and their significance for understanding shape coexistence is discussed. Experimental observables such as quadrupole moments and electromagnetic transition strengths represent furthermore important benchmarks for advancing theoretical nuclear structure models. With several new RIB facilities planned and under construction, Coulomb excitation will remain to be an important tool to extend the studies of nuclear shapes toward more exotic systems, and to obtain a more comprehensive and quantitative understanding of shape coexistence.

  11. Marine ice sheet profiles and stability under Coulomb basal conditions

    NASA Astrophysics Data System (ADS)

    Tsai, Victor; Stewart, Andrew; Thompson, Andrew

    2015-04-01

    The behavior of marine-terminating ice sheets, like the West Antarctic Ice Sheet, is of interest due to the possibility of rapid grounding line retreat and consequent catastrophic loss of ice. Critical to modeling this behavior is a choice of basal rheology, where the most popular approach is to relate the ice sheet velocity to a power-law function of basal stress. Recent experiments, however, suggest that near-grounding line tills exhibit Coulomb friction behavior. Here we address how Coulomb conditions modify ice sheet profiles and stability criteria. The basal rheology necessarily transitions to Coulomb friction near the grounding line due to low effective stresses, leading to changes in ice sheet properties within a narrow boundary layer. Ice sheet profiles 'taper off' towards a flatter upper surface, compared to the power-law case, and basal stresses vanish at the grounding line, consistent with observations. In the Coulomb case, the grounding line ice flux also depends more strongly on flotation ice thickness, which implies that ice sheets are more sensitive to climate perturbations. Furthermore, with Coulomb friction, the ice sheet grounds stably in shallower water than with a power-law rheology. This implies that smaller perturbations are required to push the grounding line into regions of negative bed slope, where it would become unstable. These results have important implications for ice sheet stability in a warming climate.

  12. PFLOW: A 3-D Numerical Modeling Tool for Calculating Fluid-Pressure Diffusion from Coulomb Strain

    NASA Astrophysics Data System (ADS)

    Wolf, L. W.; Lee, M.; Meir, A.; Dyer, G.; Ma, K.; Chan, C.

    2009-12-01

    A new 3D time-dependent pore-pressure diffusion model PFLOW is developed to investigate the response of pore fluids to the crustal deformation generated by strong earthquakes in heterogeneous geologic media. Given crustal strain generated by changes in Coulomb stress, this MATLAB-based code uses Skempton's coefficient to calculate resulting changes fluid pressure. Pore-pressure diffusion can be tracked over time in a user-defined model space with user-prescribed Neumann or Dirchilet boundary conditions and with spatially variable values of permeability. PFLOW employs linear or quadratic finite elements for spatial discretization and first order or second order, explicit or implicit finite difference discretization in time. PFLOW is easily interfaced with output from deformation modeling programs such as Coulomb (Toda et al., 2007) or 3D-DEF (Gomberg and Ellis, 1994). The code is useful for investigating to first-order the evolution of pore pressure changes induced by changes in Coulomb stress and their possible relation to water-level changes in wells or changes in stream discharge. It can also be used for student research and classroom instruction. As an example application, we calculate the coseismic pore pressure changes and diffusion induced by volumetric strain associated with the 1999 Chi-Chi earthquake (Mw = 7.6) in Taiwan. The Chi-Chi earthquake provides an unique opportunity to investigate the spatial and time-dependent poroelastic response of near-field rocks and sediments because there exist extensive observational data of water-level changes and crustal deformation. The integrated model allows us to explore whether changes in Coulomb stress can adequately explain hydrologic anomalies observed in areas such as Taiwan’s western foothills and the Choshui River alluvial plain. To calculate coseismic strain, we use the carefully calibrated finite fault-rupture model of Ma et al. (2005) and the deformation modeling code Coulomb 3.1 (Toda et al., 2007

  13. Integrated State of Oncornavirus DNA in Normal Chicken Cells and in Cells Transformed by Avian Myeloblastosis Virus

    PubMed Central

    Markham, P. D.; Baluda, M. A.

    1973-01-01

    The covalent linkage of oncornavirus-specific DNA to chicken DNA was investigated in normal chicken embryo fibroblasts (CEF) and in virus-producing leukemic cells transformed by avian myeloblastosis virus (AMV). The virus-specific sequences present in cellular DNA fractionated by different methods were detected by DNA-RNA hybridization by using 70S AMV RNA as a probe. In CEF and in leukemic cells, the viral DNA appeared to be present only in the nucleus. After cesium chloride-ethidium bromide density equilibrium sedimentation, the viral DNA was present as linear, double-stranded molecules not separable from linear chicken DNA. After extraction by the Hirt procedure, the viral DNA precipitated with the high-molecular-weight DNA. After alkaline sucrose velocity sedimentation, the viral DNA cosedimented with the high-molecular-weight cellular DNA. The results indicate that in both types of cells studied, the oncornavirus-specific DNA sequences were linked by alkali stable bonds to nuclear cellular DNA of high molecular weight and did not appear to be present in free form of any size. PMID:4359950

  14. Temperature and concentration fields in a generator integrated to single stage heat transformer using Water/Carrol mixture

    NASA Astrophysics Data System (ADS)

    Gómez-Arias, E.; Ibarra-Bahena, J.; Velazquez-Avelar, L.; Romero, R. J.; Rodríguez-Martínez, A.; Montiel-González, M.

    2014-12-01

    The generator is the starter device of single stage heat transformer ( SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines. This article reports a study of the generation of steam and changes in the concentration of the working solution (Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect. It is considered the analysis of six experimental tests; two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position (90 degree inclination). The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position. The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position, the steam generation and the change in the concentration of the working solution occurring in the middle of the plate (or at greater distance depending to the thermodynamic conditions) and instantly in vertical position (at the input of the plate).

  15. A fully integrated multi-band ED-mode pHEMT VCO using variable transformer and switched resonator

    NASA Astrophysics Data System (ADS)

    Ke, Po-Yu; Chiu, Hsien-Chin; Fu, Jeffrey S.

    2012-06-01

    A systematic approach to the design of a reconfigurable LC-coupled voltage-controlled oscillator (VCO) is proposed in this article. The focus is on the choice of the reactive elements of the resonance tank which are most suitable to switch to the desired oscillation frequencies. The optimum Q of the tank will be determined by the selected component. We report a 0.5-µm enhancement-depletion (ED) mode pHEMT (HEMT, high-electron mobility transistor) multiple-frequency VCO, and the generation of multiple frequencies are achieved using switched resonator topology. LC-tank circuit is built by square transformers. By careful selection of the reactive elements, evenly distributed results showed at each designed band. The multi-band ED-mode pHEMT VCO showed the output power of -4.7 dBm for 2 GHz band, -6.67 dBm for 3.86 GHz band and -5.9 dBm for 4.5 GHz band, respectively. The phase noises at 1 MHz offset frequency from carrier were -112.8 dBc/Hz for 2 GHz, -105 dBc/Hz for 3.86 GHz and -103.3 dBc/Hz for 4.5 GHz, respectively. The total chip size is only 1.17 × 0.83 mm2.

  16. Impact-acoustics inspection of tile-wall bonding integrity via wavelet transform and hidden Markov models

    NASA Astrophysics Data System (ADS)

    Luk, B. L.; Liu, K. P.; Tong, F.; Man, K. F.

    2010-05-01

    The impact-acoustics method utilizes different information contained in the acoustic signals generated by tapping a structure with a small metal object. It offers a convenient and cost-efficient way to inspect the tile-wall bonding integrity. However, the existence of the surface irregularities will cause abnormal multiple bounces in the practical inspection implementations. The spectral characteristics from those bounces can easily be confused with the signals obtained from different bonding qualities. As a result, it will deteriorate the classic feature-based classification methods based on frequency domain. Another crucial difficulty posed by the implementation is the additive noise existing in the practical environments that may also cause feature mismatch and false judgment. In order to solve this problem, the work described in this paper aims to develop a robust inspection method that applies model-based strategy, and utilizes the wavelet domain features with hidden Markov modeling. It derives a bonding integrity recognition approach with enhanced immunity to surface roughness as well as the environmental noise. With the help of the specially designed artificial sample slabs, experiments have been carried out with impact acoustic signals contaminated by real environmental noises acquired under practical inspection background. The results are compared with those using classic method to demonstrate the effectiveness of the proposed method.

  17. Weak interaction rate Coulomb corrections in big bang nucleosynthesis

    SciTech Connect

    Smith, Christel J.; Fuller, George M.

    2010-03-15

    We have applied a fully relativistic Coulomb wave correction to the weak reactions in the full Kawano/Wagoner big bang nucleosynthesis (BBN) code. We have also added the zero-temperature radiative correction. We find that using this higher accuracy Coulomb correction results in good agreement with previous work, giving only a modest {approx}0.04% increase in helium mass fraction over correction prescriptions applied previously in BBN calculations. We have calculated the effect of these corrections on other light element abundance yields in BBN, and we have studied these yields as functions of electron neutrino lepton number. This has allowed insights into the role of the weak neutron-proton interconversion processes in the setting of the neutron-to-proton ratio during the BBN epoch. We find that the lepton capture processes' contributions to this ratio are only second order in the Coulomb correction.

  18. Imaging quantum Hall Coulomb islands inside a quantum ring

    NASA Astrophysics Data System (ADS)

    Martins, Frederico; Hackens, Benoit; Faniel, Sebastien; Bayot, Vincent; Pala, Marco; Sellier, Hermann; Huant, Serge; Desplanque, Ludovic; Wallart, Xavier

    2011-03-01

    In the quantum Hall regime near integer filling factors, electrons are transmitted through edge states confined at the borders of the device. In mesoscopic samples, however, edge states may be sufficiently close to allow electrons to tunnel, or to be transmitted through localized states (``Coulomb islands''). Here, we use the biased tip of a low temperature scanning gate microscope to alter tunneling through quantum Hall Coulomb islands localized inside a quantum ring patterned in an InGaAs/InAlAs heterostructure. Simultaneously, we map the quantum ring resistance and observe different sets of concentric resistance fringes, due to charging/discharging of each Coulomb island. Tuning the magnetic field and the tip voltage, we reveal the rich and complex behaviour of these fringes.

  19. Long-range Coulomb interaction in nodal-ring semimetals

    NASA Astrophysics Data System (ADS)

    Huh, Yejin; Moon, Eun-Gook; Kim, Yong Baek

    2016-01-01

    Recently there have been several proposals of materials predicted to be nodal-ring semimetals, where zero energy excitations are characterized by a nodal ring in the momentum space. This class of materials falls between the Dirac-like semimetals and the more conventional Fermi-surface systems. As a step towards understanding this unconventional system, we explore the effects of the long-range Coulomb interaction. Due to the vanishing density of states at the Fermi level, Coulomb interaction is only partially screened and remains long-ranged. Through renormalization group and large-Nf computations, we have identified a nontrivial interacting fixed point. The screened Coulomb interaction at the interacting fixed point is an irrelevant perturbation, allowing controlled perturbative evaluations of physical properties of quasiparticles. We discuss unique experimental consequences of such quasiparticles: acoustic wave propagation, anisotropic dc conductivity, and renormalized phonon dispersion as well as energy dependence of quasiparticle lifetime.

  20. Integration of metabolomics and in vitro metabolism assays for investigating the stereoselective transformation of triadimefon in rainbow trout.

    PubMed

    Kenneke, John F; Ekman, Drew R; Mazur, Chris S; Konwick, Brad J; Fisk, Aaron T; Avants, Jimmy K; Garrison, A Wayne

    2010-02-01

    Triadimefon is a systemic agricultural fungicide of the triazole class whose major metabolite, triadimenol, also a commercial fungicide, provides the majority of the actual fungicidal activity, i.e., inhibition of steroid demethylation. Both chemicals are chiral: triadimefon has one chiral center with two enantiomers while its enzymatic reduction to triadimenol produces a second chiral center and two diastereomers with two enantiomers each. All six stereoisomers of the two fungicides were separated from each other using a chiral BGB-172 column on a GC-MS system so as to follow stereospecificity in metabolism by rainbow trout hepatic microsomes. In these microsomes the S-(+) enantiomer of triadimefon was transformed to triadimenol 27% faster than the R-(-) enantiomer, forming the four triadimenol stereoisomers at rates different from each other. The most fungi-toxic stereoisomer (1S,2R) was produced at the slowest rate; it was detectable after 8 h, but below the level of method quantitation. The triadimenol stereoisomer ratio pattern produced by the trout microsomes was very different from that of the commercial triadimenol standard, in which the most rat-toxic pair of enantiomers (known as "Diastereomer A") is about 85% of the total stereoisomer composition. The trout microsomes produced only about 4% of "Diastereomer A". Complementary metabolomic studies with NMR showed that exposure of the separate triadimefon enantiomers and the racemate to rainbow trout for 48 h resulted in different metabolic profiles in the trout liver extracts, i.e., different endogenous metabolite patterns that indicated differences in effects of the two enantiomers. PMID:19418553

  1. Modified Coulomb-Dipole Theory for 2e Photoionization

    NASA Technical Reports Server (NTRS)

    2004-01-01

    In the light of recent experiment on 2e photoionization of Li near threshold, we have considered a modification of the Coulomb-dipole theory, retaining the basic assumption that the threshold is dominated by asymmetric events in phase space [implies r(sub 1), k(sub 1)) greater than or equal to 2(r(sub 2), k(sub )]. In this region [in a collinear model, 2/r(sub 12) approached + 2/(r(sub 1)+r(sub 2)] the interaction reduces to V(rIsub 1) is greater than or equal to 2r(sub 2) is identically equal to [(-Z/r(sub 2)-(A-1)/r(sub 1)] + [(-2r(sub 2)/r(sub 1 exp 2)] is identically equal to V(sub c)+[V(sub d)]. For two electron emission Z = 2, thus both electrons see a Coulomb potential (V(sub c)) asymptotically, albeit each seeing a different charge. The residual potential (V(sub d)) is dipole in character. Writing the total psi = psi (sub c) + psi(sub d) = delta psi, and noting that. (T+V(sub c)-E)psy(sub c) = 0 and (T+V(sub c))psi(sub d) = 0 can be solved exactly, we find, substituting psi into the complete Schrod. Eq., that delta psi = -(H-E)(exp -1)(V(sub d) psi(sub 0)+V(sub c psi (sub 1). Using the fact that the absolute value of V(sub c) is much more than the absolute value of V(sub d) in almost all of configuration space, we can replace H by H(sub 0) in 9H-E)(exp -1) to obtain an improved approximation psi (improved) = psi(sub c) + psi(sub d) -(H(sub 0)-E)(exp -1) (V(sub c) psi (sub 0) + V(sub c) psi(sub 1). Here's the Green's function (H(sub 0)-E)(exp -1), can be exhibited explicitly, but the last term in psi (improved) is small, compared to the first two terms. Inserting them into the transition matrix element, which one handles in the usual way, we obtain in the limit E approaches 0, the threshold law: Q(E) alpha E + M(E)E(exp 5/4) + higher order (Eq. 1a). The modulation function, M(E), is a well-defined (but very non-trivial integral, but it is expected to be well approximated by a sinusoidal function containing a dipole phase term (M(E) = c sin[alpha log (E

  2. Hydrodynamic Coulomb drag of strongly correlated electron liquids

    NASA Astrophysics Data System (ADS)

    Apostolov, S. S.; Levchenko, A.; Andreev, A. V.

    2014-03-01

    We develop a theory of Coulomb drag in ultraclean double layers with strongly correlated carriers. In the regime where the equilibration length of the electron liquid is shorter than the interlayer spacing the main contribution to the Coulomb drag arises from hydrodynamic density fluctuations. The latter consist of plasmons driven by fluctuating longitudinal stresses, and diffusive modes caused by temperature fluctuations and thermal expansion of the electron liquid. We express the drag resistivity in terms of the kinetic coefficients of the electron fluid. Our results are nonperturbative in interaction strength and do not assume Fermi-liquid behavior of the electron liquid.

  3. Strong Coulomb effects in hole-doped Heisenberg chains

    NASA Astrophysics Data System (ADS)

    Schnack, J.

    2005-06-01

    Substances such as the “telephone number compound” Sr14Cu24O41 are intrinsically hole-doped. The involved interplay of spin and charge dynamics is a challenge for theory. In this article we propose to describe hole-doped Heisenberg spin rings by means of complete numerical diagonalization of a Heisenberg Hamiltonian that depends parametrically on hole positions and includes the screened Coulomb interaction among the holes. It is demonstrated that key observables like magnetic susceptibility, specific heat, and inelastic neutron scattering cross section depend sensitively on the dielectric constant of the screened Coulomb potential.

  4. Observation of ionic Coulomb blockade in nanopores.

    PubMed

    Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; Di Ventra, Massimiliano; Radenovic, Aleksandra

    2016-08-01

    Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels. PMID:27019385

  5. On rate-state and Coulomb failure models

    USGS Publications Warehouse

    Gomberg, J.; Beeler, N.; Blanpied, M.

    2000-01-01

    We examine the predictions of Coulomb failure stress and rate-state frictional models. We study the change in failure time (clock advance) Δt due to stress step perturbations (i.e., coseismic static stress increases) added to "background" stressing at a constant rate (i.e., tectonic loading) at time t0. The predictability of Δt implies a predictable change in seismicity rate r(t)/r0, testable using earthquake catalogs, where r0 is the constant rate resulting from tectonic stressing. Models of r(t)/r0, consistent with general properties of aftershock sequences, must predict an Omori law seismicity decay rate, a sequence duration that is less than a few percent of the mainshock cycle time and a return directly to the background rate. A Coulomb model requires that a fault remains locked during loading, that failure occur instantaneously, and that Δt is independent of t0. These characteristics imply an instantaneous infinite seismicity rate increase of zero duration. Numerical calculations of r(t)/r0 for different state evolution laws show that aftershocks occur on faults extremely close to failure at the mainshock origin time, that these faults must be "Coulomb-like," and that the slip evolution law can be precluded. Real aftershock population characteristics also may constrain rate-state constitutive parameters; a may be lower than laboratory values, the stiffness may be high, and/or normal stress may be lower than lithostatic. We also compare Coulomb and rate-state models theoretically. Rate-state model fault behavior becomes more Coulomb-like as constitutive parameter a decreases relative to parameter b. This is because the slip initially decelerates, representing an initial healing of fault contacts. The deceleration is more pronounced for smaller a, more closely simulating a locked fault. Even when the rate-state Δt has Coulomb characteristics, its magnitude may differ by some constant dependent on b. In this case, a rate-state model behaves like a modified

  6. Microwave ac Conductivity Spectrum of a Coulomb Glass

    SciTech Connect

    Lee, Mark; Stutzmann, M. L.

    2001-07-30

    We report the first observation of the transition between interacting and noninteracting behavior in the ac conductivity spectrum {sigma}({omega}) of a doped semiconductor in its Coulomb glass state near T=0 K . The transition manifests itself as a crossover from approximately linear frequency dependence below {approx}10 GHz , to quadratic dependence above {approx}15 GHz . The sharpness of the transition and the magnitude of the crossover frequency strongly suggest that the transition is driven by photon-induced excitations across the Coulomb gap, in contrast to existing theoretical descriptions.

  7. Higher-order dynamical effects in Coulomb dissociation

    SciTech Connect

    Esbensen, H.; Bertsch, G.F.; Bertulani, C.A.

    1995-08-01

    Coulomb dissociation is a technique commonly used to extract the dipole response of nuclei far from stability. This technique is applicable if the dissociation is dominated by dipole transitions and if first-order perturbation theory is valid. In order to assess the significance of higher-order processes we solve numerically the time evolution of the wave function for a two-body breakup in the Coulomb field from a high Z target. We applied this method to the breakup reactions: {sup 11}Be {yields} {sup 10}Be + n and {sup 11}Li {yields} +2n. The latter is treated as a two-body breakup, using a di-neutron model.

  8. Geometrically-frustrated pseudogap phase of Coulomb liquids

    NASA Astrophysics Data System (ADS)

    Pramudya, Y.; Terletska, H.; Pankov, S.; Manousakis, E.; Dobrosavljević, V.

    2012-06-01

    We study a class of models with long-range repulsive interactions of the generalized Coulomb form V(r)∼1/rα. We show that decreasing the interaction exponent in the regime αCoulomb liquid then survives in a broad pseudogap phase found at T>Tc, which is characterized by an unusual temperature dependence of all quantities. In contrast, the leading critical behavior very close to the charge-ordering temperature remains identical as in models with short-range interactions.

  9. Coulomb explosion in aromatic molecules and their deuterated derivatives

    NASA Astrophysics Data System (ADS)

    Tzallas, P.; Kosmidis, C.; Graham, P.; Ledingham, K. W. D.; McCanny, T.; Hankin, S. M.; Singhal, R. P.; Taday, P. F.; Langley, A. J.

    2000-12-01

    Coulomb explosion within some aromatic molecules (furan, pyrrole, pyridine and pyrazine) and their deuterated derivatives induced by strong fs laser fields (˜ 4×10 16 W/cm2) is studied at λ=790 nm by means of time-of-flight (TOF) mass spectrometry. It is found that in hydrogenated molecules the Coulomb explosion process begins at internuclear distances about twice larger than the equilibrium distance ( Re), while the expansion of the molecular skeleton in the deuterated derivatives is smaller. Based on the estimated kinetic energy values of the fragment ions, the charge distribution in the transient molecular species is also discussed.

  10. Coulomb-damped resonant generators using piezoelectric transduction

    NASA Astrophysics Data System (ADS)

    Miller, L. M.; Mitcheson, P. D.; Halvorsen, E.; Wright, P. K.

    2012-06-01

    Switching interface circuits employed with piezoelectric energy harvesters can increase the electrical damping considerably over that achievable with passive rectifiers. We show that a piezoelectric harvester coupled to certain types of switching circuits becomes a Coulomb-damped resonant generator. This allows analysis of such harvester systems within a well-known framework and, subject to practical constraints, allows the optimal electrical damping to be achieved. In the piezoelectric pre-biasing technique, the Coulomb damping is set by a pre-bias voltage whose optimal value is derived as a function of piezoelectric harvester parameters.

  11. Amplitude Function of Asymptotic Correlations Along Charged Wall in Coulomb Fluids

    NASA Astrophysics Data System (ADS)

    Šamaj, Ladislav

    2016-05-01

    In classical semi-infinite Coulomb fluids, two-point correlation functions exhibit a slow inverse-power law decay along a uniformly charged wall. In this work, we concentrate on the corresponding amplitude function which depends on the distances of the two points from the wall. Recently Šamaj (J Stat Phys 161:227-249 2015), applying a technique of anticommuting variables to a 2D system of charged rectilinear wall with "counter-ions only", we derived a relation between the amplitude function and the density profile which holds for any temperature. In this paper, using the Möbius conformal transformation of particle coordinates in a disc, a new relation between the amplitude function and the density profile is found for that model. In all exactly solvable cases, the amplitude function factorizes itself in the two distances from the wall. Presupposing this factorization property at any temperature and using specific sum rules for semi-infinite geometries, a relation between the amplitude function of the charge-charge structure function and the charge profile is derived for many-component Coulomb fluids in any dimension.

  12. Amplitude Function of Asymptotic Correlations Along Charged Wall in Coulomb Fluids

    NASA Astrophysics Data System (ADS)

    Šamaj, Ladislav

    2016-07-01

    In classical semi-infinite Coulomb fluids, two-point correlation functions exhibit a slow inverse-power law decay along a uniformly charged wall. In this work, we concentrate on the corresponding amplitude function which depends on the distances of the two points from the wall. Recently Šamaj (J Stat Phys 161:227-249 2015), applying a technique of anticommuting variables to a 2D system of charged rectilinear wall with "counter-ions only", we derived a relation between the amplitude function and the density profile which holds for any temperature. In this paper, using the Möbius conformal transformation of particle coordinates in a disc, a new relation between the amplitude function and the density profile is found for that model. In all exactly solvable cases, the amplitude function factorizes itself in the two distances from the wall. Presupposing this factorization property at any temperature and using specific sum rules for semi-infinite geometries, a relation between the amplitude function of the charge-charge structure function and the charge profile is derived for many-component Coulomb fluids in any dimension.

  13. Integrated adenovirus type 12 DNA in the transformed hamster cell line T637: sequence arrangements at the termini of viral DNA and mode of amplification.

    PubMed Central

    Eick, D; Doerfler, W

    1982-01-01

    Approximately 20 to 22 copies of adenovirus type 12 (Ad12) DNA per cell were integrated into the genome of the cell line T637. Only a few of these copies seemed to remain intact and colinear with virion DNA. All other persisting viral genomes exhibited deletions or inversions or both in the right-hand part of Ad12 DNA. Spontaneously arising morphological revertants of T637 cells has lost viral DNA. In most of the revertant cell lines only the intact or a part of the intact viral genome was preserved; other revertant cell lines has lost all viral DNA. In three other Ad12-transformed hamster cell lines, HA12/7, A2497-3, and CLAC3 (Stabel et al., J. Virol. 36:22-40, 1980), major rearrangements at the right end of the integrated Ad12 DNA were not found. These studies were performed to investigate the phenomena of amplification, rearrangements, and deletions of Ad12 DNA in hamster cells. Images PMID:6283150

  14. Modulational instability and higher-order rogue waves with parameters modulation in a coupled integrable AB system via the generalized Darboux transformation

    NASA Astrophysics Data System (ADS)

    Wen, Xiao-Yong; Yan, Zhenya

    2015-12-01

    We study higher-order rogue wave (RW) solutions of the coupled integrable dispersive AB system (also called Pedlosky system), which describes the evolution of wave-packets in a marginally stable or unstable baroclinic shear flow in geophysical fluids. We propose its continuous-wave (CW) solutions and existent conditions for their modulation instability to form the rogue waves. A new generalized N-fold Darboux transformation (DT) is proposed in terms of the Taylor series expansion for the spectral parameter in the Darboux matrix and its limit procedure and applied to the CW solutions to generate multi-rogue wave solutions of the coupled AB system, which satisfy the general compatibility condition. The dynamical behaviors of these higher-order rogue wave solutions demonstrate both strong and weak interactions by modulating parameters, in which some weak interactions can generate the abundant triangle, pentagon structures, etc. Particularly, the trajectories of motion of peaks and depressions of profiles of the first-order RWs are explicitly analyzed. The generalized DT method used in this paper can be extended to other nonlinear integrable systems. These results may be useful for understanding the corresponding rogue-wave phenomena in fluid mechanics and related fields.

  15. Modulational instability and higher-order rogue waves with parameters modulation in a coupled integrable AB system via the generalized Darboux transformation.

    PubMed

    Wen, Xiao-Yong; Yan, Zhenya

    2015-12-01

    We study higher-order rogue wave (RW) solutions of the coupled integrable dispersive AB system (also called Pedlosky system), which describes the evolution of wave-packets in a marginally stable or unstable baroclinic shear flow in geophysical fluids. We propose its continuous-wave (CW) solutions and existent conditions for their modulation instability to form the rogue waves. A new generalized N-fold Darboux transformation (DT) is proposed in terms of the Taylor series expansion for the spectral parameter in the Darboux matrix and its limit procedure and applied to the CW solutions to generate multi-rogue wave solutions of the coupled AB system, which satisfy the general compatibility condition. The dynamical behaviors of these higher-order rogue wave solutions demonstrate both strong and weak interactions by modulating parameters, in which some weak interactions can generate the abundant triangle, pentagon structures, etc. Particularly, the trajectories of motion of peaks and depressions of profiles of the first-order RWs are explicitly analyzed. The generalized DT method used in this paper can be extended to other nonlinear integrable systems. These results may be useful for understanding the corresponding rogue-wave phenomena in fluid mechanics and related fields. PMID:26723154

  16. Transforming growth factor-β1 receptor inhibition preserves glomerulotubular integrity during ureteral obstruction in adults but worsens injury in neonatal mice

    PubMed Central

    Galarreta, Carolina I.; Thornhill, Barbara A.; Forbes, Michael S.; Simpkins, Lauren N.; Kim, Dae-Kee

    2013-01-01

    Unilateral ureteral obstruction (UUO), a widely used model of chronic kidney disease and congenital obstructive uropathy, causes proximal tubular injury and formation of atubular glomeruli. Because transforming growth factor-β1 (TGF-β1) is a central regulator of renal injury, neonatal and adult mice were subjected to complete UUO while under general anesthesia and treated with vehicle or ALK5 TGF-β1 receptor inhibitor (IN-1130, 30 mg·kg−1·day−1). After 14 days, glomerulotubular integrity and proximal tubular mass were determined by morphometry of Lotus tetragonolobus lectin distribution, and the fraction of atubular glomeruli was determined by serial section analysis of randomly selected individual glomeruli. Glomerular area, macrophage infiltration, fibronectin distribution, and interstitial collagen were measured by morphometry. Compared with placebo, inhibition of TGF-β1 by IN-1130 decreased apoptosis and formation of atubular glomeruli, prevented parenchymal loss, increased glomerular area and glomerulotubular integrity, and increased proximal tubule fraction of the adult obstructed kidney parenchyma from 17 to 30% (P < 0.05, respectively). IN-1130 decreased macrophage infiltration and fibronectin and collagen deposition in the adult obstructed kidney by ∼50% (P < 0.05, respectively). In contrast to these salutary effects in the adult, IN-1130 caused widespread necrosis in obstructed neonatal kidneys. We conclude that whereas IN-1130 reduces obstructive injury in adult kidneys through preservation of glomerulotubular integrity and proximal tubular mass, TGF-β1 inhibition aggravates obstructive injury in neonates. These results indicate that while caution is necessary in treating congenital uropathies, ALK5 inhibitors may prevent nephron loss due to adult kidney disease. PMID:23303407

  17. An Operator Method for Evaluating Laplace Transforms

    ERIC Educational Resources Information Center

    Lanoue, B. G.; Yurekli, O.

    2005-01-01

    This note discusses a simple operator technique based on the differentiation and shifting properties of the Laplace transform to find Laplace transforms for various elementary functions. The method is simpler than known integration techniques to evaluate Laplace transforms.

  18. Coulomb repulsion and the electron beam directed energy weapon

    NASA Astrophysics Data System (ADS)

    Retsky, Michael W.

    2004-09-01

    Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into small spots at large distances from defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Based on estimates, the nonreversible terms should be small - of the order of 0.1 mm. If this is true, it is possible to design a practical electron beam directed weapon not limited by Coulomb repulsion.

  19. Finiteness of the Coulomb gauge QCD perturbative effective action

    NASA Astrophysics Data System (ADS)

    Andraši, A.; Taylor, J. C.

    2015-05-01

    At 2-loop order in the Coulomb gauge, individual Feynman graphs contributing to the effective action have energy divergences. It is proved that these cancel in suitable combinations of graphs. This has previously been shown only for transverse external fields. The calculation results in a generalization of the Christ-Lee term which was inserted into the Hamiltonian.

  20. Hamiltonian flow in Coulomb gauge Yang-Mills theory

    SciTech Connect

    Leder, Markus; Reinhardt, Hugo; Pawlowski, Jan M.; Weber, Axel

    2011-01-15

    We derive a new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge. The flow equations for the static gluon and ghost propagators are solved under the assumption of ghost dominance within different diagrammatic approximations. The results are compared to those obtained in the variational approach and the reliability of the approximations is discussed.

  1. Limits to Electron Beam Emittance from Stochastic Coulomb Interactions

    SciTech Connect

    Coleman-Smith, Christopher; Padmore, Howard A.; Wan, Weishi

    2008-08-22

    Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.

  2. Coulomb Interactions in Hanbury Brown-Twiss Experiments with Electrons

    ERIC Educational Resources Information Center

    Shen, Kan

    2009-01-01

    This dissertation examines the effect of Coulomb interactions in Hanbury Brown-Twiss (HBT) type experiments with electrons. HBT experiments deal with intensity interference, which is related to the second-order correlation function of the particle field. This is an extension of the usual amplitude interference experiment, such as Young's…

  3. The Coulomb problem on a 3-sphere and Heun polynomials

    NASA Astrophysics Data System (ADS)

    Bellucci, Stefano; Yeghikyan, Vahagn

    2013-08-01

    The paper studies the quantum mechanical Coulomb problem on a 3-sphere. We present a special parametrization of the ellipto-spheroidal coordinate system suitable for the separation of variables. After quantization we get the explicit form of the spectrum and present an algebraic equation for the eigenvalues of the Runge-Lentz vector. We also present the wave functions expressed via Heun polynomials.

  4. The Coulomb problem on a 3-sphere and Heun polynomials

    SciTech Connect

    Bellucci, Stefano; Yeghikyan, Vahagn

    2013-08-15

    The paper studies the quantum mechanical Coulomb problem on a 3-sphere. We present a special parametrization of the ellipto-spheroidal coordinate system suitable for the separation of variables. After quantization we get the explicit form of the spectrum and present an algebraic equation for the eigenvalues of the Runge-Lentz vector. We also present the wave functions expressed via Heun polynomials.

  5. Coulomb Crystals in Cylindrical Dusty Plasmas under Gravity/Microgravity

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazuo; Totsuji, Hiroo; Adachi, Satoshi

    2014-10-01

    Coulomb crystals of dusty plasmas have been studied under microgravity with utilities boarding on the International Space Station in a joint Russian/German research project. Dynamics of the Coulomb crystals in cylindrical plasmas is investigated with the apparatus of PK-4 being launched till the end of 2014. A science team in Japan studied the cylindrical dusty plasmas to contribute to the project with the PK-4J modified original for microgravity experiments of parabolic flights in Japan. In the experiments, the dust particles distributed at the off-centered position close to the bottom in balancing of gravity. Under microgravity, they changed the distribution and formed a Coulomb crystal around the center axis in the plasmas. Several particles arranged in a line parallel to the axis, and the lines piled up to a bundle. Spatial distribution of the dust particles affects on plasma parameters of ion density and electron temperature. Structures of the Coulomb crystals connected to the parameters are discussed. The present study were supported by JAXA and Diamond Air Service.

  6. Coulomb gauge approach for charmonium meson and hybrid radiative transitions

    NASA Astrophysics Data System (ADS)

    Gou, Peng; Yépez-Martínez, Tochtli; Szczepaniak, Adam P.

    2015-01-01

    We consider the lowest order interaction of the Foldy-Wouthuysen QED and QCD Hamiltonian in the Coulomb gauge approach, to describe radiative transitions between conventional and hybrids charmonium mesons. The results are compared to potential quark models and lattices calculations.

  7. Interpolating the Coulomb phase of little string theory

    DOE PAGESBeta

    Lin, Ying -Hsuan; Shao, Shu -Heng; Wang, Yifan; Yin, Xi

    2015-12-03

    We study up to 8-derivative terms in the Coulomb branch effective action of (1,1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity onmore » the Coulomb branch, numerically from SU(k) SYM and DSLST respectively, for k=2,3,4,5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. As a result, we also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2,0) little string theory.« less

  8. Interpolating the Coulomb phase of little string theory

    SciTech Connect

    Lin, Ying -Hsuan; Shao, Shu -Heng; Wang, Yifan; Yin, Xi

    2015-12-03

    We study up to 8-derivative terms in the Coulomb branch effective action of (1,1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity on the Coulomb branch, numerically from SU(k) SYM and DSLST respectively, for k=2,3,4,5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. As a result, we also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2,0) little string theory.

  9. Interpolating the Coulomb phase of little string theory

    NASA Astrophysics Data System (ADS)

    Lin, Ying-Hsuan; Shao, Shu-Heng; Wang, Yifan; Yin, Xi

    2015-12-01

    We study up to 8-derivative terms in the Coulomb branch effective action of (1, 1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity on the Coulomb branch, numerically from SU( k) SYM and DSLST respectively, for k = 2 , 3 , 4 , 5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. We also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2 , 0) little string theory.

  10. Accurate Coulomb blockade thermometry up to 60 kelvin.

    PubMed

    Meschke, M; Kemppinen, A; Pekola, J P

    2016-03-28

    We demonstrate experimentally a precise realization of Coulomb blockade thermometry working at temperatures up to 60 K. Advances in nano-fabrication methods using electron beam lithography allow us to fabricate uniform arrays of sufficiently small tunnel junctions to guarantee an overall temperature reading precision of about 1%. PMID:26903107

  11. Coulomb gauge approach for charmonium meson and hybrid radiative transitions

    DOE PAGESBeta

    Gou, Peng; Yepez-Martínez, Tochtli; Szczepaniak, Adam P.

    2015-01-22

    We consider the lowest order interaction of the Foldy-Wouthuysen QED and QCD Hamiltonian in the Coulomb gauge approach, to describe radiative transitions between conventional and hybrids charmonium mesons. The results are compared to potential quark models and lattices calculations.

  12. Finiteness of the Coulomb gauge QCD perturbative effective action

    SciTech Connect

    Andraši, A.; Taylor, J.C.

    2015-05-15

    At 2-loop order in the Coulomb gauge, individual Feynman graphs contributing to the effective action have energy divergences. It is proved that these cancel in suitable combinations of graphs. This has previously been shown only for transverse external fields. The calculation results in a generalization of the Christ–Lee term which was inserted into the Hamiltonian.

  13. Coulomb effects on edge scattering in elastic nuclear collisions

    SciTech Connect

    Silveira, R. da; Leclercq-Willain, Ch.

    2011-04-15

    We present a qualitative analysis of the effects of the Coulomb force on the edge scattering produced in elastic nuclear collisions occurring under strong absorption conditions. This analysis is illustrated with several examples of nucleus-nucleus and antiproton-nucleus elastic scattering.

  14. Influence of binary Coulomb collisions on nonlinear stimulated Raman backscatter in the kinetic regime

    SciTech Connect

    Finnegan, S. M.; Yin, L.; Kline, J. L.; Albright, B. J.; Bowers, K. J.

    2011-03-15

    The influence of binary Coulomb collisions on trapped particle nonlinearities related to stimulated Raman scatter (SRS) in a single laser speckle is examined using one-dimensional particle-in-cell simulations. Binary Coulomb collisions are incorporated using a numerical particle-pairing algorithm that reproduces a collision integral of the Landau form. The onset of nonlinearly enhanced levels of SRS reflectivity is shown to coincide with electron trapping in the daughter plasma wave and is sensitive to the collisional scattering rate. Relaxation of trapping-induced perturbations to the electron velocity distribution via collisional velocity space diffusion is predicted to have the largest effect on the onset of SRS when the amplitude of the daughter plasma wave is smallest, and trapping-induced perturbations to the electron velocity distribution function are also small. In the absence of higher dimensional detrapping mechanisms (e.g., electron side-loss), it is shown that the onset threshold for enhanced SRS reflectivity is determined predominantly by the parallel diffusion of trapped electrons scattering from bulk thermal electrons, and that for the conditions studied here, the contribution to detrapping from perpendicular diffusion is non-negligible. Additionally, inverse bremsstrahlung heating of the bulk electrons is shown to shift the daughter plasma wave spectrum upward along the Stoke's resonance to larger wave frequency and smaller wave number, changing the linear parametric coupling conditions to SRS backscatter as a function of time. The reduction in SRS reflectivity from binary Coulomb collisions is greatest for laser intensities near the collisionless onset threshold, ulimately leading to an increase in the onset threshold laser intensity for enhanced SRS reflectivity in the kinetic regime.

  15. Accurate calculation of Coulomb sums: Efficacy of Pade-like methods

    SciTech Connect

    Sarkar, B. ); Bhattacharyya, K. )

    1993-09-01

    The adequacy of numerical sequence accelerative transforms in providing accurate estimates of Coulomb sums is considered, referring particularly to distorted lattices. Performance of diagonal Pade approximants (DPA) in this context is critically assessed. Failure in the case of lattice vacancies is also demonstrated. The method of multiple-point Pade approximants (MPA) has been introduced for slowly convergent sequences and is shown to work well for both regular and distorted lattices, the latter being due either to impurities or vacancies. Viability of the two methods is also compared. In divergent situations with distortions owing to vacancies, a strategy of obtaining reliable results by separate applications of both DPA and MPA at appropriate places is also sketched. Representative calculations involve two basic cubic-lattice sums, one slowly convergent and the other divergent, from which very good quality estimates of Madelung constants for a number of common lattices follow.

  16. Analysis of space-time non-stationary patterns of rainfall-groundwater interactions by integrating empirical orthogonal function and cross wavelet transform methods

    NASA Astrophysics Data System (ADS)

    Yu, Hwa-Lung; Lin, Yuan-Chien

    2015-06-01

    Rainfall-groundwater interactions are complex and can depend upon a variety of hydro-geological and geographical conditions and can commonly present high nonlinearity. This study proposed an integration of cross wavelet transform and empirical orthogonal function (EOF) analysis to analyze the space-time nonlinear relationships between the precipitation and groundwater changes. The proposed method was applied to investigating the non-stationary and nonlinear precipitation-groundwater relationships in Pingtung Plain aquifer during 2005-2010. We analyzed daily groundwater and rainfall observations at 47 wells and 27 stations across the study area operated by Taiwan Water Resources Agency and Central Weather Bureau respectively. Results show that EOF method revealed three major space-time patterns of the groundwater levels. The cross wavelet transform further identified the lagged effects between precipitation and groundwater changes. The temporal lags can vary not only with respect to the temporal scales of groundwater processes, but also the different identified groundwater regions, which can associate with distinct physical mechanisms. In general, the lagged periods between high frequency signals of precipitation and groundwater can range from 0 to 18 days, showing how rainfall events perturbed the groundwater levels across space. The long-term lags for the three identified underlying groundwater processes were 3.71, 56.6, and 72.07 days, respectively, showing seasonal recharge patterns can depend upon the geographical and geological conditions. Our results distinguished the space-time recharge processes in different frequencies, which present nonlinear and non-stationary rainfall-recharge interactions of a groundwater system, which can be spatially and frequency dependent.

  17. Controlling the reproducibility of Coulomb blockade phenomena for gold nanoparticles on an organic monolayer/silicon system.

    PubMed

    Caillard, L; Sattayaporn, S; Lamic-Humblot, A-F; Casale, S; Campbell, P; Chabal, Y J; Pluchery, O

    2015-02-13

    Two types of highly ordered organic layers were prepared on silicon modified with an amine termination for binding gold nanoparticles (AuNPs). These two grafted organic monolayers (GOMs), consisting of alkyl chains with seven or 11 carbon atoms, were grafted on oxide-free Si(111) surfaces as tunnel barriers between the silicon electrode and the AuNPs. Three kinds of colloidal AuNPs were prepared by reducing HAuCl4 with three different reactants: citrate (Turkevich synthesis, diameter ∼16 nm), ascorbic acid (diameter ∼9 nm), or NaBH4 (Natan synthesis, diameter ∼7 nm). Scanning tunnel spectroscopy (STS) was performed in a UHV STM at 40 K, and Coulomb blockade behaviour was observed. The reproducibility of the Coulomb behavior was analysed as a function of several chemical and physical parameters: size, crystallinity of the AuNPs, influence of surrounding surfactant molecules, and quality of the GOM/Si interface (degree of oxidation after the full processing). Samples were characterized with scanning tunneling microscope, STS, atomic force microscope, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy (XPS), and high resolution transmission electronic microscope. We show that the reproducibility in observing Coulomb behavior can be as high as ∼80% with the Natan synthesis of AuNPs and GOMs with short alkyl chains. PMID:25611611

  18. Compact Collision Kernels for Hard Sphere and Coulomb Cross Sections; Fokker-Planck Coefficients

    SciTech Connect

    Chang Yongbin; Shizgal, Bernie D.

    2008-12-31

    A compact collision kernel is derived for both hard sphere and Coulomb cross sections. The difference between hard sphere interaction and Coulomb interaction is characterized by a parameter {eta}. With this compact collision kernel, the calculation of Fokker-Planck coefficients can be done for both the Coulomb and hard sphere interactions. The results for arbitrary order Fokker-Planck coefficients are greatly simplified. An alternate form for the Coulomb logarithm is derived with concern to the temperature relaxation in a binary plasma.

  19. Data recovery and integration from public databases uncovers transformation-specific transcriptional downregulation of cAMP-PKA pathway-encoding genes

    PubMed Central

    Balestrieri, Chiara; Alberghina, Lilia; Vanoni, Marco; Chiaradonna, Ferdinando

    2009-01-01

    Background The integration of data from multiple genome-wide assays is essential for understanding dynamic spatio-temporal interactions within cells. Such integration, which leads to a more complete view of cellular processes, offers the opportunity to rationalize better the high amount of "omics" data freely available in several public databases. In particular, integration of microarray-derived transcriptome data with other high-throughput analyses (genomic and mutational analysis, promoter analysis) may allow us to unravel transcriptional regulatory networks under a variety of physio-pathological situations, such as the alteration in the cross-talk between signal transduction pathways in transformed cells. Results Here we sequentially apply web-based and statistical tools to a case study: the role of oncogenic activation of different signal transduction pathways in the transcriptional regulation of genes encoding proteins involved in the cAMP-PKA pathway. To this end, we first re-analyzed available genome-wide expression data for genes encoding proteins of the downstream branch of the PKA pathway in normal tissues and human tumor cell lines. Then, in order to identify mutation-dependent transcriptional signatures, we classified cancer cells as a function of their mutational state. The results of such procedure were used as a starting point to analyze the structure of PKA pathway-encoding genes promoters, leading to identification of specific combinations of transcription factor binding sites, which are neatly consistent with available experimental data and help to clarify the relation between gene expression, transcriptional factors and oncogenes in our case study. Conclusions Genome-wide, large-scale "omics" experimental technologies give different, complementary perspectives on the structure and regulatory properties of complex systems. Even the relatively simple, integrated workflow presented here offers opportunities not only for filtering data noise

  20. Experimental study of the 15O(2p, γ)17Ne cross section by Coulomb Dissociation for the rp process

    NASA Astrophysics Data System (ADS)

    Marganiec, J.; Warners, F.; Aksouh, F.; Aksyutina, Y.; Alvarez Pol, H.; Aumann, T.; Beceiro, S.; Bertulani, C.; Boretzky, K.; Borge, M. J.; Chartier, M.; Chatillon, A.; Chulkov, L.; Cortina-Gil, D.; Egorova, I.; Emling, H.; Ershova, O.; Forssén, C.; Fraile, L. M.; Fynbo, H.; Galaviz, D.; Geissel, H.; Grigorenko, L.; Heil, M.; Hoffmann, D. H. H.; Hoffmann, J.; Johansson, H.; Jonson, B.; Karakoç, M.; Karagiannis, C.; Kiselev, O.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Langer, C.; Lantz, M.; Larsson, K.; Le Bleis, T.; Lemmon, R.; Litvinov, Yu A.; Mahata, K.; Müntz, C.; Nilsson, T.; Nociforo, C.; Nyman, G.; Ott, W.; Panin, V.; Parfenova, Yu; Paschalis, S.; Perea, A.; Plag, R.; Reifarth, R.; Richter, A.; Riisager, K.; Rodríguez Tajes, C.; Rossi, D.; Schrieder, G.; Shulgina, N.; Simon, H.; Stroth, J.; Sümmerer, K.; Taylor, J.; Tengblad, O.; Tengborn, E.; Weick, H.; Wiescher, M.; Wimmer, C.; Zhukov, M.

    2016-01-01

    The time-reversed reaction 15O(2p, γ)17Ne has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of 20Ne in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-R3B experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (σCoul) have been calculated, which provide a photoabsorption (σphoto) and a radiative capture cross section (σcap). Additionally, important information about the nuclear structure of the 17Ne nucleus will be obtained. The analysis is in progress.

  1. Parallelization of Four-Component Calculations. I. Integral Generation, SCF, and Four-Index Transformation in the Dirac-Fock Package MOLFDIR.

    SciTech Connect

    Pernpointner, M.; Visscher, Lucas; De Jong, Wibe A.; Broer, R.

    2000-10-01

    The treatment of relativity and electron correlation on an equal footing is essential for the computation of systems containing heavy elements. Correlation treatments that are based on four-component Dirac-Hartree-Fock calculations presently provide the most accurate, albeit costly, way of taking relativity into account. The requirement of having two expansion basis sets for the molecular wave function puts a high demand on computer resources. The treatment of larger systems is thereby often prohibited by the very large run times and files that arise in a conventional Dirac-Hartree-Fock approach. A possible solution for this bottleneck is a parallel approach that not only reduces the turnaround time but also spreads out the large files over a number of local disks. Here, we present a distributed-memory parallelization of the program package MOLFDIR for the integral generation, Dirac-Hartree-Fock and four-index MS transformation steps. This implementation scales best for large AO spaces and moderately sized active spaces.

  2. Reconfiguration and Control of Non-Equal Mass Three-Craft Coulomb Formation

    NASA Astrophysics Data System (ADS)

    Ting, Wang; Guangqing, Xia; Nan, Zhao

    2016-03-01

    The paper studied reconfiguration of Coulomb formation from three-craft system to four-craft system. Assumed that three-craft Coulomb system already formed a triangle configuration, then, the fourth Coulomb craft is scheduled to join the existing system so as to form a new static configuration. New possible configurations such as quadrilateral in 2-dimension and tetrahedron in 3-dimension for four-craft Coulomb formation are discussed in the paper. The processing of reconfiguration will not change the original origin and triangle formation. Through the Particle Swarm Optimization (PSO) algorithm, the mass, the charge and the position of the fourth Coulomb craft can be calculated for these configurations.

  3. Ion wake effects on the Coulomb ion drag in complex dusty plasmas

    SciTech Connect

    Ki, Dae-Han; Jung, Young-Dae

    2010-09-06

    The ion wake effects on the Coulomb drag force are investigated in complex dusty plasmas. It is shown that the ion wake effects significantly enhance the Coulomb ion drag force. It is also found that the ion wake effects on the Coulomb drag force increase with an increase in the Debye length. In addition, the ion wake effects on the momentum transfer cross section and Coulomb drag force are found to be increased with increasing thermal Mach number, i.e., decreasing plasma temperature. It is also found that the Coulomb ion drag force would be stronger for smaller dust grains.

  4. Is the ground state of Yang-Mills theory Coulombic?

    SciTech Connect

    Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; McMullan, D.; Lutz, W.

    2008-08-01

    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.

  5. Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene

    PubMed Central

    Mihnev, Momchil T.; Tolsma, John R.; Divin, Charles J.; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A.; MacDonald, Allan H.; Norris, Theodore B.

    2015-01-01

    In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron–phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied. PMID:26399955

  6. Characterization of ion Coulomb crystals for fundamental sciences

    NASA Astrophysics Data System (ADS)

    Okada, Kunihiro; Ichikawa, Masanari; Wada, Michiharu

    2015-11-01

    We performed classical molecular dynamics (MD) simulations in order to search the conditions for efficient sympathetic cooling of highly charged ions (HCIs) in a linear Paul trap. Small two-component ion Coulomb crystals consisting of laser-cooled ions and HCIs were characterized by the results of the MD simulations. We found that the spatial distribution is determined by not only the charge-to-mass ratio but also the space charge effect. Moreover, the simulation results suggest that the temperature of HCIs do not necessarily decrease with increasing the number of laser-cooled ions in the cases of linear ion crystals. We also determined the cooling limit of sympathetically cooled 165Ho14+ ions in small linear ion Coulomb crystals. The present results show that sub-milli-Kelvin temperatures of at least 10 Ho14+ ions will be achieved by sympathetic cooling with a single laser-cooled Be+.

  7. Stationary entanglement between two nanomechanical oscillators induced by Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Qin, Wu; Yin, Xiao; Zhi-Ming, Zhang

    2016-01-01

    We propose a scheme for entangling two nanomechanical oscillators by Coulomb interaction in an optomechanical system. We find that the steady-state entanglement of two charged nanomechanical oscillators can be obtained when the coupling between them is stronger than a critical value which relies on the detuning. Remarkably, the degree of entanglement can be controlled by the Coulomb interaction and the frequencies of the two charged oscillators. Project supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91121023), the National Natural Science Foundation of China (Grant Nos. 61378012, 60978009, and 11574092), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20124407110009), the National Basic Research Program of China (Grant Nos. 2011CBA00200 and 2013CB921804), and the Program for Changjiang Scholar and Innovative Research Team in University, China (Grant No. IRT1243).

  8. Interplay of Coulomb interaction and spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Bünemann, Jörg; Linneweber, Thorben; Löw, Ute; Anders, Frithjof B.; Gebhard, Florian

    2016-07-01

    We employ the Gutzwiller variational approach to investigate the interplay of Coulomb interaction and spin-orbit coupling in a three-orbital Hubbard model. Already in the paramagnetic phase we find a substantial renormalization of the spin-orbit coupling that enters the effective single-particle Hamiltonian for the quasiparticles. Only close to half band-filling and for sizable Coulomb interaction do we observe clear signatures of Hund's atomic rules for spin, orbital, and total angular momentum. For a finite local Hund's rule exchange interaction we find a ferromagnetically ordered state. The spin-orbit coupling considerably reduces the size of the ordered moment, it generates a small ordered orbital moment, and it induces a magnetic anisotropy. To investigate the magnetic anisotropy energy, we use an external magnetic field that tilts the magnetic moment away from the easy axis (1 ,1 ,1 ) .

  9. Coulomb excitation of C{sub 60} molecules

    SciTech Connect

    Esbensen, H.; Berry, H.G.; Cheng, S.

    1995-08-01

    The ionization and dissociation of C{sub 60} molecules in the Coulomb field from fast, highly-charged xenon ions was measured recently at ATLAS. The Coulomb excitation was modeled as a coherent excitation of the giant plasmon resonance. Guided by photo-absorption measurements, single-plasmon excitations were identified with the production of single-charged C{sub 60}{sup +} molecular ions. The calculated cross sections do indeed reproduce the beam energy-dependence of the measured C{sub 60}{sup +} yield. The calculations show that single-plasmon excitations are responsible for about half of the total reaction cross section. The other half, i.e., multiplasmon excitations, leads to multiple ionization and dissociation of the molecule.

  10. Conductance of a proximitized nanowire in the Coulomb blockade regime

    NASA Astrophysics Data System (ADS)

    van Heck, B.; Lutchyn, R. M.; Glazman, L. I.

    2016-06-01

    We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.

  11. Effect of Coulomb screening length on nuclear "pasta" simulations

    NASA Astrophysics Data System (ADS)

    Alcain, P. N.; Giménez Molinelli, P. A.; Nichols, J. I.; Dorso, C. O.

    2014-05-01

    We study the role of the effective Coulomb interaction strength and length on the dynamics of nucleons in conditions according to those in a neutron star's crust. Calculations were made with a semiclassical molecular dynamics model, studying isospin symmetric matter at subsaturation densities and low temperatures. The electrostatic interaction between protons is included as a screened Coulomb potential in the spirit of the Thomas-Fermi approximation, but the screening length is artificially varied to explore its effect on the formation of the nonhomogeneous nuclear structures known as "nuclear pasta." As the screening length increases, we can see a transition from a one-per-cell pasta regime (due exclusively to finite-size effects) to a more appealing multiple pasta per simulation box. This qualitative difference in the structure of neutron star matter at low temperatures shows that special caution should be taken when the screening length is estimated for numerical simulations.

  12. Coulomb attraction in optical spectra of quantum discs

    NASA Astrophysics Data System (ADS)

    Adolph, B.; Glutsch, S.; Bechstedt, F.

    1994-06-01

    We present a theory which describes the influence of the Coulomb interaction on the optical spectra of quantum discs within the envelope function formalism. Starting from a non-local Elliott formula luminescence is traced back to two-particle wave functions and energies. They are solutions of the corresponding Schrödinger equation for an electron-hole pair under the influence of the Coulomb attraction and confinement potentials determined by the spatial variation of the band edges of the considered microstructure. We present a complete numerical solution of the two-particle problem for flat quantum dots, i.e. discs for which the size quantization in growth direction is much stronger than that in the xy-plane. We discuss two different situations, single discs with infinite and finite confinement potentials. Resulting theoretical lineshapes are compared with luminescence spectra obtained recently for quantum discs fabricated by laser-induced thermal cation interdiffusion in quantum-well structures.

  13. Imaging Coulomb islands in a quantum Hall interferometer.

    PubMed

    Hackens, B; Martins, F; Faniel, S; Dutu, C A; Sellier, H; Huant, S; Pala, M; Desplanque, L; Wallart, X; Bayot, V

    2010-01-01

    In the quantum Hall regime, near integer filling factors, electrons should only be transmitted through spatially separated edge states. However, in mesoscopic systems, electronic transmission turns out to be more complex, giving rise to a large spectrum of magnetoresistance oscillations. To explain these observations, recent models put forward the theory that, as edge states come close to each other, electrons can hop between counterpropagating edge channels, or tunnel through Coulomb islands. Here, we use scanning gate microscopy to demonstrate the presence of QH Coulomb islands, and reveal the spatial structure of transport inside a QH interferometer. Locations of electron islands are found by modulating the tunnelling between edge states and confined electron orbits. Tuning the magnetic field, we unveil a continuous evolution of active electron islands. This allows to decrypt the complexity of high-magnetic-field magnetoresistance oscillations, and opens the way to further local-scale manipulations of QH localized states. PMID:20975700

  14. Coulomb effects in low-energy nuclear fragmentation

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Chun, Sang Y.; Badavi, Francis F.; John, Sarah

    1993-01-01

    Early versions of the Langley nuclear fragmentation code NUCFRAG (and a publicly released version called HZEFRG1) assumed straight-line trajectories throughout the interaction. As a consequence, NUCFRAG and HZEFRG1 give unrealistic cross sections for large mass removal from the projectile and target at low energies. A correction for the distortion of the trajectory by the nuclear Coulomb fields is used to derive fragmentation cross sections. A simple energy-loss term is applied to estimate the energy downshifts that greatly alter the Coulomb trajectory at low energy. The results, which are far more realistic than prior versions of the code, should provide the data base for future transport calculations. The systematic behavior of charge-removal cross sections compares favorably with results from low-energy experiments.

  15. Elastic scattering of Beryllium isotopes near the Coulomb barrier

    SciTech Connect

    Di Pietro, A.; Figuera, P.; Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D.; Papa, M.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.

    2011-10-28

    In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.

  16. Coulomb blockage of hybridization in two-dimensional DNA arrays

    NASA Astrophysics Data System (ADS)

    Vainrub, Arnold; Pettitt, B. Montgomery

    2002-10-01

    Experiments on DNA microarrays have revealed substantial differences in hybridization thermodynamics between DNA free in solution and surface tethered DNA. Here we develop a mean field model of the Coulomb effects in two-dimensional DNA arrays to understand the binding isotherms and thermal denaturation of the double helix. We find that the electrostatic repulsion of the assayed nucleic acid from the array of DNA probes dominates the binding thermodynamics, and thus causes the Coulomb blockage of the hybridization. The results explain, observed in DNA microarrays, the dramatic decrease of the hybridization efficiency and the thermal denaturation curve broadening as the probe surface density grows. We demonstrate application of the theory for evaluation and optimization of the sensitivity, specificity, and the dynamic range of DNA array devices.

  17. ``Perfect'' Coulomb Drag in a Bilayer Quantum Hall System

    NASA Astrophysics Data System (ADS)

    Nandi, D.; Finck, A. D. K.; Eisenstein, J. P.; Pfeiffer, L. N.; West, K. W.

    2012-02-01

    We report Coulomb drag measurements in Corbino geometry which reveal that equal but oppositely directed electrical currents can freely propagate across the insulating bulk of the bilayer quantized Hall state at νT=1 even when the two 2D layers are electrically isolated and interlayer tunneling has been heavily suppressed by an in-plane magnetic field. This effect, which we dub ``perfect'' Coulomb drag, reflects the transport of charge neutral excitons across the bulk of the 2D system. The equal magnitude of the drive and drag currents is lost at high current and when either the temperature or effective separation between the two 2D layers is increased. In each of these cases, ordinary quasiparticle charge transport across the annulus has grown to dominate over exciton transport.

  18. Structural phase transitions and topological defects in ion Coulomb crystals

    SciTech Connect

    Partner, Heather L.; Nigmatullin, Ramil; Burgermeister, Tobias; Keller, Jonas; Pyka, Karsten; Plenio, Martin B.; Retzker, Alex; Zurek, Wojciech Hubert; del Campo, Adolfo; Mehlstaubler, Tanja E.

    2014-11-19

    We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.

  19. Quantum solution for the one-dimensional Coulomb problem

    SciTech Connect

    Nunez-Yepez, H. N.; Salas-Brito, A. L.; Solis, Didier A.

    2011-06-15

    The one-dimensional hydrogen atom has been a much studied system with a wide range of applications. Since the pioneering work of Loudon [R. Loudon, Am. J. Phys. 27, 649 (1959).], a number of different features related to the nature of the eigenfunctions have been found. However, many of the claims made throughout the years in this regard are not correct--such as the existence of only odd eigenstates or of an infinite binding-energy ground state. We explicitly show that the one-dimensional hydrogen atom does not admit a ground state of infinite binding energy and that the one-dimensional Coulomb potential is not its own supersymmetric partner. Furthermore, we argue that at the root of many such false claims lies the omission of a superselection rule that effectively separates the right side from the left side of the singularity of the Coulomb potential.

  20. Simulation of Coulomb interaction effects in electron sources

    NASA Astrophysics Data System (ADS)

    Rouse, John; Zhu, Xieqing; Liu, Haoning; Munro, Eric

    2011-07-01

    Over many years, we have developed electron source simulation software that has been used widely in the electron optics community to aid the development of rotationally symmetric electron and ion guns. The simulation includes the modelling of cathode emission and the effects of volumetric space charge. In the present paper we describe the existing software and explain how we have extended this software to include the effects of discrete Coulomb interactions between the electrons as they travel from the cathode surface to the exit of the gun. In the paper, we will describe the numerical models we have employed, the techniques we have used to maximize the speed of the Coulomb force computation and present several illustrative examples of cases analyzed using the new software, including thermal field emitters, LaB 6 guns and flat dispenser-type cathodes.

  1. Coulomb's Law Corrections from a Gauge-Kinetic Mixing

    NASA Astrophysics Data System (ADS)

    Gaete, Patricio; Schmidt, Iván

    We study the connection or equivalence between two well-known extensions of the Standard Model, that is, for the coupling between the familiar massless electromagnetism U(1)QED and a hidden-sector U(1)h, and axionic electrodynamics. Our discussion is carried out using the gauge-invariant but path-dependent variables formalism, which is an alternative to the Wilson loop approach. When we compute in this way the static quantum potential for the coupling between the familiar massless electromagnetism U(1)QED and a hidden-sector U(1)h, the result of this calculation is a Yukawa correction to the usual static Coulomb potential. Previously,14, we have shown that axionic electrodynamics has a different structure which is reflected in a confining piece. Therefore, both extensions of the Standard Model are not equivalent. Interestingly, when the above calculation is done inside a superconducting box, the Coulombic piece disappears leading to a screening phase.

  2. Conductance through a proximitized nanowire in the Coulomb blockade regime

    NASA Astrophysics Data System (ADS)

    van Heck, Bernard; Lutchyn, Roman; Glazman, Leonid

    Motivated by recent experiments of the Copenhagen group on InAs nanowires with epitaxial Al, we investigate the two-terminal conductance of a strongly proximitized nanowire in the Coulomb blockade regime. We identify the leading electron transport processes at zero applied magnetic field B as well as at finite fields, suppressing the induced gap Δind (B) . In the conventional superconducting phase, the conductance is controlled by the sequential Cooper pair tunneling if Δind (B) exceeds the charging energy Ec, and by the elastic single-electron processes if Δind (B) Coulomb blockade peaks, which explains the experimental finding in Ref.. We also develop a quantitative theory for the differential conductance and examine its evolution across the topological transition point.

  3. Cooling of cryogenic electron bilayers via the Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Gamble, John King; Friesen, Mark; Joynt, Robert; Coppersmith, S. N.

    2011-09-01

    Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure and analyze the power transfer. We show that, across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.

  4. Coulomb chronometry to probe the decay mechanism of hot nuclei

    NASA Astrophysics Data System (ADS)

    Gruyer, D.; Frankland, J. D.; Bonnet, E.; Chbihi, A.; Ademard, G.; Boisjoli, M.; Borderie, B.; Bougault, R.; Galichet, E.; Gauthier, J.; Guinet, D.; Lautesse, P.; Le Neindre, N.; Legouée, E.; Lombardo, I.; Lopez, O.; Manduci, L.; Marini, P.; Mazurek, K.; Nadtochy, P. N.; Pârlog, M.; Rivet, M. F.; Roy, R.; Rosato, E.; Spadaccini, G.; Verde, G.; Vient, E.; Vigilante, M.; Wieleczko, J. P.; Indra Collaboration

    2015-12-01

    In 129Xe+natSn central collisions from 8 to 25 MeV/nucleon, the three-fragment exit channel occurs with a significant cross section. We show that these fragments arise from two successive binary splittings of a heavy composite system. The sequence of fragment production is determined. Strong Coulomb proximity effects are observed in the three-fragment final state. A comparison with Coulomb trajectory calculations shows that the time scale between the consecutive breakups decreases with increasing bombarding energy, becoming quasisimultaneous above excitation energy E*=4.0 ±0.5 MeV /nucleon . This transition from sequential to simultaneous breakup was interpreted as the signature of the onset of multifragmentation for the three-fragment exit channel in this system.

  5. Extended Kepler-Coulomb quantum superintegrable systems in three dimensions

    NASA Astrophysics Data System (ADS)

    Kalnins, E. G.; Kress, J. M.; Miller, W., Jr.

    2013-03-01

    The quantum Kepler-Coulomb system in three dimensions is well known to be second order superintegrable, with a symmetry algebra that closes polynomially under commutators. This polynomial closure is also typical for second order superintegrable systems in 2D and for second order systems in 3D with nondegenerate (four-parameter) potentials. However, the degenerate three-parameter potential for the 3D Kepler-Coulomb system (also second order superintegrable) is an exception, as its symmetry algebra does not close polynomially. The 3D four-parameter potential for the extended Kepler-Coulomb system is not even second order superintegrable, but Verrier and Evans (2008 J. Math. Phys. 49 022902) showed it was fourth order superintegrable, and Tanoudis and Daskaloyannis (2011 arXiv:11020397v1) showed that, if a second fourth order symmetry is added to the generators, the symmetry algebra closes polynomially. Here, based on the Tremblay, Turbiner and Winternitz construction, we consider an infinite class of quantum extended Kepler-Coulomb three- and four-parameter systems indexed by a pair of rational numbers (k1, k2) and reducing to the usual systems when k1 = k2 = 1. We show these systems to be superintegrable of arbitrarily high order and determine the structure of their symmetry algebras. We demonstrate that the symmetry algebras close algebraically; only for systems admitting extra discrete symmetries is polynomial closure achieved. Underlying the structure theory is the existence of raising and lowering operators, not themselves symmetry operators or even defined independent of basis, that can be employed to construct the symmetry operators and their structure relations.

  6. Stability characterizations of fixtured rigid bodies with Coulomb friction

    SciTech Connect

    PANG,J.S.; TRINKLE,JEFFREY C.

    2000-02-15

    This paper formally introduces several stability characterizations of fixtured three-dimensional rigid bodies initially at rest and in unilateral contact with Coulomb friction. These characterizations, weak stability and strong stability, arise naturally from the dynamic model of the system, formulated as a complementarity problem. Using the tools of complementarity theory, these characterizations are studied in detail to understand their properties and to develop techniques to identify the stability classifications of general systems subjected to known external loads.

  7. Electron screening of the Coulomb potential at small internuclear distances

    NASA Astrophysics Data System (ADS)

    Zinoviev, A. N.

    2015-07-01

    Values of He+-Au potential at small internuclear distances (R = 10-4 to 10-3 nm) have been obtained from the Rutherford backscattering (RBS) data. The potential has been shown to be independent of the collision velocity and close to the potential approximation proposed in Zinoviev (2011) [1]. Experimental data on the electron screening of the Coulomb potential enabled calculation of corrections for the nuclear fusion cross-sections and improvement of the RBS data quantitative analysis.

  8. Coulomb excitations for a short linear chain of metallic shells

    SciTech Connect

    Zhemchuzhna, Liubov; Gumbs, Godfrey; Iurov, Andrii; Huang, Danhong; Gao, Bo

    2015-03-15

    A self-consistent-field theory is given for the electronic collective modes of a chain containing a finite number, N, of Coulomb-coupled spherical two-dimensional electron gases arranged with their centers along a straight line, for simulating electromagnetic response of a narrow-ribbon of metallic shells. The separation between nearest-neighbor shells is arbitrary and because of the quantization of the electron energy levels due to their confinement to the spherical surface, all angular momenta L of the Coulomb excitations, as well as their projections M on the quantization axis, are coupled. However, for incoming light with a given polarization, only one angular momentum quantum number is usually required. Therefore, the electromagnetic response of the narrow-ribbon of metallic shells is expected to be controlled externally by selecting different polarizations for incident light. We show that, when N = 3, the next-nearest-neighbor Coulomb coupling is larger than its value if they are located at opposite ends of a right-angle triangle forming the triad. Additionally, the frequencies of the plasma excitations are found to depend on the orientation of the line joining them with respect to the axis of quantization since the magnetic field generated from the induced oscillating electric dipole moment on one sphere can couple to the induced magnetic dipole moment on another. Although the transverse inter-shell electromagnetic coupling can be modeled by an effective dynamic medium, the longitudinal inter-shell Coulomb coupling, on the other hand, can still significantly modify the electromagnetic property of this effective medium between shells.

  9. Wigner solids, classical Coulomb lattices, and invariant average potential

    NASA Astrophysics Data System (ADS)

    Hall, G. L.; Rice, T. R.

    1980-04-01

    We show that Hall's analysis of K for Wigner solids, the Ihm and Cohen analysis of the Fuchs energy ɛ, some extensions of Hall's analysis, and some recent results for the classical Coulomb-lattice model provide a tight theoretical framework useful beyond the matter of Hall's conclusions about the ɛ for Wigner solids based on an incorrect relation accepted from the literature. We also comment on spherical approximations.

  10. Coulomb interaction from the interplay between confinement and screening

    NASA Astrophysics Data System (ADS)

    Gaete, P.; Guendelman, E. I.

    2004-07-01

    It has been noticed that confinement effects can be described by the addition of a -FμνaFaμν term in the Lagrangian density. We now study the combined effect of such "confinement term" and that of a mass term. The surprising result is that the interplay between these two terms gives rise to a Coulomb interaction. Our picture has a certain correspondence with the quasiconfinement picture described by Giles, Jaffe and de Rujula for QCD with symmetry breaking.

  11. Coulomb field scattering in Born-Infeld electrodynamics

    SciTech Connect

    Tennant, Daniel

    2011-02-15

    In the context of Born-Infeld electrodynamics, the electromagnetic fields interact with each other via their nonlinear couplings. A calculation will be performed where an incoming electromagnetic plane wave scatters off a Coulomb field in the geometrical optics approximation. In addition to finding the first-order angle of deflection, exact solutions for the trajectory will also be found. The possibility of electromagnetic bound states will be discussed.

  12. Can Coulomb repulsion for charged particle beams be overcome?

    NASA Astrophysics Data System (ADS)

    Retsky, Michael W.

    2004-01-01

    Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into a small spots at large distances from the defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Since the nonreversible terms should be small, it might be possible to construct an electron beam directed energy weapon.

  13. Strong Coulomb effects on pions produced in heavy ion collisons

    NASA Astrophysics Data System (ADS)

    Sullivan, J. P.; Bistirlich, J. A.; Bowman, H. R.; Bossingham, R.; Buttke, T.; Crowe, K. M.; Frankel, K. A.; Martoff, C. J.; Miller, J.; Murphy, D. L.; Rasmussen, J. O.; Zajc, W. A.; Hashimoto, O.; Koike, M.; Péter, J.; Benenson, W.; Crawley, G. M.; Kashy, E.; Nolen, J. A.

    1982-03-01

    Doubly differential cross sections for the production of π+ and π- near the velocity of the incident beam for pion laboratory angles from 0 to 20 degrees are presented. Beams of 20Ne with EA=280, 380, and 480 MeV and 40Ar with EA=535 MeV incident on C, NaF, KCl, Cu, and U targets were used. A sharp peak in the π- spectrum and a depression in the π+ spectrum is observed at 0° near the incident projectile velocity. The effect is explained in terms of Coulomb interactions between pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffmann and an effective projectile fragment charge are made. The relationship between these data and previously measured projectile fragmentation data is discussed and a simple parametrization of projectile mass, target mass, and beam energy dependence of the differential cross sections is given. NUCLEAR REACTIONS C, NaF, Cu, U (20Ne,π+/-)X, EA=280-480 MeV; C, KCl (40Ar,π+/-)X, EA=535 MeV; measured σ(Eπ,θπ), θπ=0°-20°, π velocity near beam velocity; deduced projectile fragment charges, Coulomb effects.

  14. Optimal reconfigurations of two-craft Coulomb formations along manifolds

    NASA Astrophysics Data System (ADS)

    Jones, Drew R.; Schaub, Hanspeter

    2013-02-01

    Coulomb formations refer to swarms of closely flying spacecraft, in which the net electric charge of each vehicle is controlled. Active charge control is central to this concept and enables a propulsion system with highly desirable characteristics, albeit with limited controllability. Numerous Coulomb formation equilibria have been derived, but to maintain and maneuver these configurations, some inertial thrust is required to supplement the nearly propellant-less charge control. In this work, invariant manifold theory is applied to two-craft Coulomb equilibria, which are admitted in a linearized two-body gravity model. The manifolds associated with these systems are analyzed for the first time, and are then utilized as part of a general procedure for formulating optimal reconfigurations. Specifically, uncontrolled flows along the manifolds are sought which provide near continuous transfers from one equilibrium to another. Control is then introduced to match continuity, while minimizing inertial thrusting. This methodology aims to exploit uncontrolled motions and charge control to realize the shape-changing ability of these formations, without large inertial control efforts. Some variations in formulating and parameterizing the optimal transfers are discussed, and analytical expressions are derived to aid in establishing control parameter limits, under certain assumptions. Numerical results are provided, as demonstrative examples of the optimization procedure, using relatively simple control approximations. Finally, Particle Swarm Optimization, a novel stochastic method, is used with considerable success to solve the numerically difficult parameter optimization problems.

  15. Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule

    NASA Astrophysics Data System (ADS)

    Cloët, Ian C.; Bentz, Wolfgang; Thomas, Anthony W.

    2016-01-01

    In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q |≳0.5 GeV . The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.

  16. Photoelectron wave function in photoionization: plane wave or Coulomb wave?

    PubMed

    Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I

    2015-11-19

    The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion. PMID:26509428

  17. Electron interactions in graphene through an effective Coulomb potential

    NASA Astrophysics Data System (ADS)

    Rodrigues, Joao N. B.; Adam, Shaffique

    A recent numerical work [H.-K. Tang et al, PRL 115, 186602 (2015)] considering graphene's π-electrons interacting through an effective Coulomb potential that is finite at short-distances, stressed the importance of the sp2 -electrons in determining the semimetal to Mott insulator phase transition in graphene. Some years ago, I. F. Herbut [PRL 97, 146401 (2006)] studied such a transition by mapping graphene's π-electrons into a Gross-Neveu model. From a different perspective, D. T. Son [PRB 75, 235423 (2007)] put the emphasis on the long-range interactions by modelling graphene as Dirac fermions interacting through a bare Coulomb potential. Here we build on these works and explore the phase diagram of Dirac fermions interacting through an effective Coulomb-like potential screened at short-distances. The interaction potential used allows for analytic results that controllably switch between the two perspectives above. This work was supported by the Singapore National Research Foundation (NRF-NRFF2012-01 and CA2DM medium-sized centre program) and by the Singapore Ministry of Education and Yale-NUS College (R-607-265-01312).

  18. Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule.

    PubMed

    Cloët, Ian C; Bentz, Wolfgang; Thomas, Anthony W

    2016-01-22

    In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q|≳0.5  GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei. PMID:26849589

  19. Quasi-exactly solvable relativistic soft-core Coulomb models

    SciTech Connect

    Agboola, Davids Zhang, Yao-Zhong

    2012-09-15

    By considering a unified treatment, we present quasi exact polynomial solutions to both the Klein-Gordon and Dirac equations with the family of soft-core Coulomb potentials V{sub q}(r)=-Z/(r{sup q}+{beta}{sup q}){sup 1/q}, Z>0, {beta}>0, q{>=}1. We consider cases q=1 and q=2 and show that both cases are reducible to the same basic ordinary differential equation. A systematic and closed form solution to the basic equation is obtained using the Bethe ansatz method. For each case, the expressions for the energies and the allowed parameters are obtained analytically and the wavefunctions are derived in terms of the roots of a set of Bethe ansatz equations. - Highlights: Black-Right-Pointing-Pointer The relativistic bound-state solutions of the soft-core Coulomb models. Black-Right-Pointing-Pointer Quasi-exact treatments of the Dirac and Klein-Gordon equations for the soft-core Coulomb models. Black-Right-Pointing-Pointer Solutions obtained in terms of the roots to the Bethe ansatz equations. Black-Right-Pointing-Pointer The hidden Lie algebraic structure discussed for the models. Black-Right-Pointing-Pointer Results useful in describing mesonic atoms and interaction of intense laser fields with atom.

  20. Implosive Interatomic Coulombic decay in the simplest molecular anion

    NASA Astrophysics Data System (ADS)

    Greene, Chris H.; Perez-Rios, Jesus; Slipchenko, Lyudmila

    2016-05-01

    Interatomic Coulombic decay (ICD) has been extensively studied in different systems: from diatomic systems such as He2 up to more complex chemical systems with interest in biochemistry. Independently of the size and complexity of the system, the ICD process proposed involves the emission of an electron through exchange of a virtual photon. The present theoretical study investigates the ICD process in the helium hydride anion, which involves two final product states that can be produced through a Coulomb implosion following high energy ejection of a He 1s electron accompanied by excitation to He+(n = 2) . One of the subsequent decay channels is associated with the usual emission of a single electron, to produce a stable molecule: HeH+, which can compete with the usual dissociated final state of the system. The second channel involves the emission of two electrons, leading to the usual Coulomb explosion of the final product ions He+(1 s) + H + . In addition, the process of formation of the helium hydride anion is analyzed in terms of the existing technology of ionic molecular beams and buffer gas cooling techniques. This work is supported by the National Science Foundation under Grant PHY-1306905.

  1. [Preparation and primary genetic analysis of Drosophila melanogaster transformants line w'lz(b)/XXywf, containing mini-white genes, integrated in the genome during P-element-dependent transformation].

    PubMed

    Prokhorova, A V; Voloshina, M A; Shostak, N G; Barskiĭ, V E; Golubovskiĭ, M D

    1994-07-01

    Transformation of Drosophila melanogaster using P-element-based vectors yielded 129 sublines, which carried mini-white gene copies in the different genome regions. Dependence of mini-white gene expression on the location, gene dosage, and sex of the transformed individuals was analyzed. The mutation lzb was shown to suppress mini-white gene expression, the degree of suppression depending on the location and dosage of the mini-white gene. PMID:7958802

  2. A comparison of Coulomb and pseudo-Coulomb friction implementations: Application to the table contact phase of gymnastics vaulting.

    PubMed

    Jackson, M I; Hiley, M J; Yeadon, M R

    2011-10-13

    In the table contact phase of gymnastics vaulting both dynamic and static friction act. The purpose of this study was to develop a method of simulating Coulomb friction that incorporated both dynamic and static phases and to compare the results with those obtained using a pseudo-Coulomb implementation of friction when applied to the table contact phase of gymnastics vaulting. Kinematic data were obtained from an elite level gymnast performing handspring straight somersault vaults using a Vicon optoelectronic motion capture system. An angle-driven computer model of vaulting that simulated the interaction between a seven segment gymnast and a single segment vaulting table during the table contact phase of the vault was developed. Both dynamic and static friction were incorporated within the model by switching between two implementations of the tangential frictional force. Two vaulting trials were used to determine the model parameters using a genetic algorithm to match simulations to recorded performances. A third independent trial was used to evaluate the model and close agreement was found between the simulation and the recorded performance with an overall difference of 13.5%. The two-state simulation model was found to be capable of replicating performance at take-off and also of replicating key contact phase features such as the normal and tangential motion of the hands. The results of the two-state model were compared to those using a pseudo-Coulomb friction implementation within the simulation model. The two-state model achieved similar overall results to those of the pseudo-Coulomb model but obtained solutions more rapidly. PMID:21889150

  3. Microscopic study of 6He elastic scattering around the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Descouvemont, P.

    2016-07-01

    We investigate 6He scattering on 27Al, 58Ni, 120Sn, and 208Pb in a microscopic version of the Continuum Discretized Coupled Channel (CDCC) method. We essentially focus on energies around the Coulomb barrier. The 6He nucleus is described by an antisymmetric 6-nucleon wave function, defined in the Resonating Group Method. The 6He continuum is simulated by square-integrable positive-energy states. The model does not depend on any adjustable parameter as it is based only on well known nucleon-target potentials. We show that experimental elastic cross sections are fairly well reproduced. The calculation suggests that breakup effects increase for high target masses. For a light system such as 6He+27Al, breakup effects are small, and a single-channel approximation provides fair results.

  4. Equation satisfied by the energy-density functional for electron-electron mutual Coulomb repulsion

    SciTech Connect

    Joubert, Daniel P.

    2011-10-15

    It is shown that the electron-electron mutual Coulomb repulsion energy-density functional V{sub ee}{sup {gamma}}[{rho}] satisfies the equationV{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]-V{sub ee}{sup {gamma}}[{rho}{sub N-1}{sup {gamma}}]={integral}d{sup 3}r({delta}V{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]/{delta}{rho}{sub N}{sup 1}(r))[{rho}{sub N}{sup 1}(r)-{rho}{sub N-1}{sup {gamma}}(r)], where {rho}{sub N}{sup 1}(r) and {rho}{sub N-1}{sup {gamma}}(r) are N-electron and (N-1)-electron densities determined from the same adiabatic scaled external potential of the N-electron system at coupling strength {gamma}.

  5. An algorithm for computing screened Coulomb scattering in G EANT4

    NASA Astrophysics Data System (ADS)

    Mendenhall, Marcus H.; Weller, Robert A.

    2005-01-01

    An algorithm has been developed for the GEANT4 Monte-Carlo package for the efficient computation of screened Coulomb interatomic scattering. It explicitly integrates the classical equations of motion for scattering events, resulting in precise tracking of both the projectile and the recoil target nucleus. The algorithm permits the user to plug in an arbitrary screening function, such as Lens-Jensen screening, which is good for backscattering calculations, or Ziegler-Biersack-Littmark screening, which is good for nuclear straggling and implantation problems. This will allow many of the applications of the TRIM and SRIM codes to be extended into the much more general GEANT4 framework where nuclear and other effects can be included.

  6. How is shrimp aquaculture transforming coastal livelihoods and lagoons in Estero Real, Nicaragua? The need to integrate social-ecological research and ecosystem-based approaches.

    PubMed

    Benessaiah, Karina; Sengupta, Raja

    2014-08-01

    Ecosystem-based approaches to aquaculture integrate environmental concerns into planning. Social-ecological systems research can improve this approach by explicitly relating ecological and social dynamics of change at multiple scales. Doing so requires not only addressing direct effects of aquaculture but also considering indirect factors such as changes in livelihood strategies, governance dynamics, and power relations. We selected the community of Puerto Morazán, Nicaragua as a case study to demonstrate how the introduction of small-scale aquaculture radically transformed another key livelihood activity, lagoon shrimp fishing, and the effects that these changes have had on lagoons and the people that depend on them. We find that shrimp aquaculture played a key role in the collapse, in the 1990s, of an existing lagoon common-property management. Shrimp aquaculture-related capital enabled the adoption of a new fishing technique that not only degraded lagoons but also led to their gradual privatization. The existence of social ties between small-scale shrimp farmers and other community members mitigated the impacts of privatization, illustrating the importance of social capital. Since 2008, community members are seeking to communally manage the lagoons once again, in response to degraded environmental conditions and a consolidation of the shrimp industry at the expense of smaller actors. This research shows that shrimp aquaculture intersects with a complex set of drivers, affecting not only how ecosystems are managed but also how they are perceived and valued. Understanding these social-ecological dynamics is essential to implement realistic policies and management of mangrove ecosystems and address the needs of resource-dependent people. PMID:24912580

  7. How is Shrimp Aquaculture Transforming Coastal Livelihoods and Lagoons in Estero Real, Nicaragua?: The Need to Integrate Social-Ecological Research and Ecosystem-Based Approaches

    NASA Astrophysics Data System (ADS)

    Benessaiah, Karina; Sengupta, Raja

    2014-08-01

    Ecosystem-based approaches to aquaculture integrate environmental concerns into planning. Social-ecological systems research can improve this approach by explicitly relating ecological and social dynamics of change at multiple scales. Doing so requires not only addressing direct effects of aquaculture but also considering indirect factors such as changes in livelihood strategies, governance dynamics, and power relations. We selected the community of Puerto Morazán, Nicaragua as a case study to demonstrate how the introduction of small-scale aquaculture radically transformed another key livelihood activity, lagoon shrimp fishing, and the effects that these changes have had on lagoons and the people that depend on them. We find that shrimp aquaculture played a key role in the collapse, in the 1990s, of an existing lagoon common-property management. Shrimp aquaculture-related capital enabled the adoption of a new fishing technique that not only degraded lagoons but also led to their gradual privatization. The existence of social ties between small-scale shrimp farmers and other community members mitigated the impacts of privatization, illustrating the importance of social capital. Since 2008, community members are seeking to communally manage the lagoons once again, in response to degraded environmental conditions and a consolidation of the shrimp industry at the expense of smaller actors. This research shows that shrimp aquaculture intersects with a complex set of drivers, affecting not only how ecosystems are managed but also how they are perceived and valued. Understanding these social-ecological dynamics is essential to implement realistic policies and management of mangrove ecosystems and address the needs of resource-dependent people.

  8. Factorization of the (2+1)-dimensional BLP integrable system by the periodic fixed points of its Bäcklund transformations

    NASA Astrophysics Data System (ADS)

    Weiss, John

    1991-11-01

    Previously, we have found a factorization of the (1+1)-dimensional Toda lattice by the periodic fixed points of its Bäcklund transformations. The Toda flow is realized by two commuting, one-dimensional Hamiltonian flows. By a result of Konopelchenko, the Laplace-Darboux transformation is a Bäcklund transformation for the (2+1)-dimensional Boiti-Leon-Pempinelli (BLP) equation. A periodic fixed point of the Laplace transformation is an invariant manifold of the BLP flow. This manifold is determined by solutions of the (1+1)-dimensional Toda lattice equations. From these results we find that the 2+1 BLP flow is factored by three commuting, one-dimensional Hamiltonian flows that are the periodic fixed points of its Bäcklund transformations.

  9. Coulombic wall slip of concentrated soft-particle suspensions

    NASA Astrophysics Data System (ADS)

    Adams, Michael; Liu, Wei; Zhang, Zhibing; Fryer, Peter

    2013-06-01

    The coefficients of friction of concentrated soft-particle suspensions (tomato paste and a microgel suspension) were measured as a function of the slip velocity for a number of substrates. The data are interpreted using a micro-elastohydrodynamic model that is consistent with significant bulk frictional dissipation and an increase in the number of particle-wall contacts with increasing normal stress. The origin of the Coulombic slip, which has not been observed previously for pastes, is ascribed to the sensitivity of the lubricating film thickness.

  10. A proposal for Coulomb assisted laser cooling of piezoelectric semiconductors

    NASA Astrophysics Data System (ADS)

    Nia, Iman Hassani; Mohseni, Hooman

    2014-07-01

    Anti-Stokes laser cooling of semiconductors as a compact and vibration-free method is very attractive. While it has achieved significant milestones, increasing its efficiency is highly desirable. The main limitation is the lack of the pristine material quality with high luminescence efficiency. Here, we theoretically demonstrate that the Coulomb interaction among electrons and holes in piezoelectric heterostructures could lead to coherent damping of acoustic phonons; rendering a significantly higher efficiency that leads to the possibility of cooling a broad range of semiconductors.

  11. Proton radiography, nuclear cross sections and multiple Coulomb scattering

    SciTech Connect

    Sjue, Sky K.

    2015-11-04

    The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.

  12. A proposal for Coulomb assisted laser cooling of piezoelectric semiconductors

    SciTech Connect

    Nia, Iman Hassani; Mohseni, Hooman

    2014-07-28

    Anti-Stokes laser cooling of semiconductors as a compact and vibration-free method is very attractive. While it has achieved significant milestones, increasing its efficiency is highly desirable. The main limitation is the lack of the pristine material quality with high luminescence efficiency. Here, we theoretically demonstrate that the Coulomb interaction among electrons and holes in piezoelectric heterostructures could lead to coherent damping of acoustic phonons; rendering a significantly higher efficiency that leads to the possibility of cooling a broad range of semiconductors.

  13. Superconductor-insulator transition in the presence of Coulomb disorder

    NASA Astrophysics Data System (ADS)

    Shklovskii, B. I.

    2007-12-01

    Superconductor-insulator transition driven by the decreasing concentration of electrons n is studied in the case of the disorder potential created by randomly positioned charged impurities. Electrons and Cooper pairs (formed by a non-Coulomb attraction) nonlinearly screen the random potential of impurities. Both electrons and Cooper pairs can be delocalized or localized in the resulting self-consistent potential. The border separating the superconductor and insulator phases in the plane of the concentration of electrons and the length of the Cooper pair is found. For a strong disorder, the central segment of this border follows the Bose-Einstein-Condensation-BCS crossover line defined for a clean sample.

  14. A nonlinear Bloch model for Coulomb interaction in quantum dots

    SciTech Connect

    Bidegaray-Fesquet, Brigitte Keita, Kole

    2014-02-15

    In this paper, we first derive a Coulomb Hamiltonian for electron–electron interaction in quantum dots in the Heisenberg picture. Then we use this Hamiltonian to enhance a Bloch model, which happens to be nonlinear in the density matrix. The coupling with Maxwell equations in case of interaction with an electromagnetic field is also considered from the Cauchy problem point of view. The study is completed by numerical results and a discussion about the advisability of neglecting intra-band coherences, as is done in part of the literature.

  15. The Coulomb excitations of Bernal bilayer graphene under external fields

    SciTech Connect

    Wu, Jhao-Ying; Lin, Ming-Fa

    2014-03-31

    We study the field effects on the Coulomb excitation spectrum of Bernal bilayer graphene by using the tight-binding model and the random-phase approximation. The electric field opens the band gap and creates the saddle points, the latter brings about a prominent interband plasmon. On the other hand, the magnetic field induces the dispersionless Landau levels (LLs) that causes the inter-LL plasmons. The two kinds of field-induced plasmon modes can be further tuned by the magnitude of momentum transfer and the field strength. The predicted results may be further validated by the inelastic light-scattering or high-resolution electron-energy-loss spectroscopy (HREELLS)

  16. "Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications

    NASA Technical Reports Server (NTRS)

    Marshall, J. R.

    1999-01-01

    The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this

  17. Challenges in calculating molecular systems with Coulomb interactions

    NASA Astrophysics Data System (ADS)

    Kirnosov, Nikita; Sharkey, Keeper; Adamowicz, Ludwik

    2014-03-01

    The highly accurate quantum mechanical calculations are not only crucial for high-resolution experimental data verification, but may also serve as a guide in the field of exotic systems exploration. Including all non-relativistic effects in a single-step variational approach and rigorously separating out the center of mass motion allows us to build a reliable model for calculating bound states of molecular systems with Coulomb interactions. In these calculations the wave function of the system is expanded in terms of explicitly correlated Gaussian (ECG) basis functions. Examples of calculations of energies and other properties of some molecular systems will be presented.

  18. Topological defect motifs in two-dimensional Coulomb clusters.

    PubMed

    Radzvilavičius, A; Anisimovas, E

    2011-09-28

    We study the distribution of topological defects in two-dimensional Coulomb clusters with parabolic lateral confinement. The minima hopping algorithm based on molecular dynamics is used to efficiently locate the ground- and low-energy metastable states, and their structure is analysed by means of the Delaunay triangulation. The size, structure and distribution of geometry-induced lattice imperfections strongly depends on the system size and the energetic state. Besides isolated disclinations and dislocations, classification of defect motifs includes defect compounds-grain boundaries, rosette defects, vacancies and interstitial particles. Proliferation of defects in metastable configurations destroys the orientational order of the Wigner lattice. PMID:21891854

  19. Heavy quarks, gluons and the confinement potential in Coulomb gauge

    NASA Astrophysics Data System (ADS)

    Popovici, Carina; Watson, Peter; Reinhardt, Hugo

    2011-05-01

    We consider the heavy quark limit of Coulomb gauge QCD, with the truncation of the Yang-Mills sector to include only (dressed) two-point functions. We find that the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is nonperturbatively exact and moreover, we provide a direct connection between the temporal gluon propagator and the quark confinement potential. Further, we show that only bound states of color singlet quark-antiquark (meson) and quark-quark (SU(2) baryon) pairs are physically allowed.

  20. Heavy quarks, gluons and the confinement potential in Coulomb gauge

    SciTech Connect

    Popovici, Carina; Watson, Peter; Reinhardt, Hugo

    2011-05-23

    We consider the heavy quark limit of Coulomb gauge QCD, with the truncation of the Yang-Mills sector to include only (dressed) two-point functions. We find that the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is nonperturbatively exact and moreover, we provide a direct connection between the temporal gluon propagator and the quark confinement potential. Further, we show that only bound states of color singlet quark-antiquark (meson) and quark-quark (SU(2) baryon) pairs are physically allowed.

  1. Communication: Practical and rigorous reduction of the many-electron quantum mechanical Coulomb problem to O(N{sup 2/3}) storage

    SciTech Connect

    Pederson, Mark R.

    2015-04-14

    It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N{sup 4}) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N{sup 2}) integrals. Here, it is shown that the storage can be further reduced to O(N{sup 2/3}) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulomb integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes.

  2. Communication: practical and rigorous reduction of the many-electron quantum mechanical Coulomb problem to O(N(2/3)) storage.

    PubMed

    Pederson, Mark R

    2015-04-14

    It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N(4)) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N(2)) integrals. Here, it is shown that the storage can be further reduced to O(N(2/3)) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulomb integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes. PMID:25877555

  3. Communication: Practical and rigorous reduction of the many-electron quantum mechanical Coulomb problem to O(N2/3) storage

    NASA Astrophysics Data System (ADS)

    Pederson, Mark R.

    2015-04-01

    It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N4) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N2) integrals. Here, it is shown that the storage can be further reduced to O(N2/3) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulomb integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes.

  4. Fano effect dominance over Coulomb blockade in transport properties of parallel coupled quantum dot system

    SciTech Connect

    Brogi, Bharat Bhushan Ahluwalia, P. K.; Chand, Shyam

    2015-06-24

    Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ε + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.

  5. Protein solvation from theory and simulation: Exact treatment of Coulomb interactions in three-dimensional theories

    NASA Astrophysics Data System (ADS)

    Perkyns, John S.; Lynch, Gillian C.; Howard, Jesse J.; Pettitt, B. Montgomery

    2010-02-01

    Solvation forces dominate protein structure and dynamics. Integral equation theories allow a rapid and accurate evaluation of the effect of solvent around a complex solute, without the sampling issues associated with simulations of explicit solvent molecules. Advances in integral equation theories make it possible to calculate the angle dependent average solvent structure around an irregular molecular solution. We consider two methodological problems here: the treatment of long-ranged forces without the use of artificial periodicity or truncations and the effect of closures. We derive a method for calculating the long-ranged Coulomb interaction contributions to three-dimensional distribution functions involving only a rewriting of the system of integral equations and introducing no new formal approximations. We show the comparison of the exact forms with those implied by the supercell method. The supercell method is shown to be a good approximation for neutral solutes whereas the new method does not exhibit the known problems of the supercell method for charged solutes. Our method appears more numerically stable with respect to thermodynamic starting state. We also compare closures including the Kovalenko-Hirata closure, the hypernetted-chain (HNC) and an approximate three-dimensional bridge function combined with the HNC closure. Comparisons to molecular dynamics results are made for water as well as for the protein solute bovine pancreatic trypsin inhibitor. The proposed equations have less severe approximations and often provide results which compare favorably to molecular dynamics simulation where other methods fail.

  6. Protein solvation from theory and simulation: Exact treatment of Coulomb interactions in three-dimensional theories

    PubMed Central

    Perkyns, John S.; Lynch, Gillian C.; Howard, Jesse J.; Pettitt, B. Montgomery

    2010-01-01

    Solvation forces dominate protein structure and dynamics. Integral equation theories allow a rapid and accurate evaluation of the effect of solvent around a complex solute, without the sampling issues associated with simulations of explicit solvent molecules. Advances in integral equation theories make it possible to calculate the angle dependent average solvent structure around an irregular molecular solution. We consider two methodological problems here: the treatment of long-ranged forces without the use of artificial periodicity or truncations and the effect of closures. We derive a method for calculating the long-ranged Coulomb interaction contributions to three-dimensional distribution functions involving only a rewriting of the system of integral equations and introducing no new formal approximations. We show the comparison of the exact forms with those implied by the supercell method. The supercell method is shown to be a good approximation for neutral solutes whereas the new method does not exhibit the known problems of the supercell method for charged solutes. Our method appears more numerically stable with respect to thermodynamic starting state. We also compare closures including the Kovalenko–Hirata closure, the hypernetted-chain (HNC) and an approximate three-dimensional bridge function combined with the HNC closure. Comparisons to molecular dynamics results are made for water as well as for the protein solute bovine pancreatic trypsin inhibitor. The proposed equations have less severe approximations and often provide results which compare favorably to molecular dynamics simulation where other methods fail. PMID:20151732

  7. Protein Solvation from Theory and Simulation: Exact Treatment of Coulomb Interactions in Three-Dimensional Theories

    SciTech Connect

    Perkyns, John S.; Lynch, Gillian C.; Howard, Jesse J.; Pettitt, Bernard M.

    2010-02-14

    Solvation forces dominate protein structure and dynamics. Integral equation theories allow a rapid and accurate evaluation of the effect of solvent around a complex solute, without the sampling issues associated with simulations of explicit solvent molecules. Advances in integral equation theories make it possible to calculate the angle dependent average solvent structure around an irregular molecular solution. We consider two methodological problems here: the treatment of long-ranged forces without the use of artificial periodicity or truncations and the effect of closures. We derive a method for calculating the long-ranged Coulomb interaction contributions to three-dimensional distribution functions involving only a rewriting of the system of integral equations and introducing no new formal approximations. We show the comparison of the exact forms with those implied by the supercell method. The supercell method is shown to be a good approximation for neutral solutes whereas the new method does not exhibit the known problems of the supercell method for charged solutes. Our method appears more numerically stable with respect to thermodynamic starting state. We also compare closures including the Kovalenko–Hirata closure, the hypernetted-chain _HNC_ and an approximate three-dimensional bridge fu nction combined with the HNC closure. Comparisons to molecular dynamics results are made for water as well as for the protein solute bovine pancreatic trypsin inhibitor. The proposed equations have less severe approximations and often provide results which compare favorably to molecular dynamics simulation where other methods fail.

  8. Quasiequilibrium Characterization of Mixed-Ion Coulomb Crystals

    NASA Astrophysics Data System (ADS)

    Okada, Kunihiro; Ichikawa, Masanari; Wada, Michiharu; Schuessler, Hans A.

    2015-11-01

    We demonstrate the application of reliable methods to determine both the average micromotion energies and the number of sympathetically cooled ions (SCIs) embedded in mixed-ion Coulomb crystals in a linear Paul trap. The number of the SCIs and the micromotion energies for the observed mixed-ion crystals are determined by comparing experimentally obtained images with molecular-dynamics simulations, where the kinetic energies of SCIs trapped in rf fields are averaged in cold elastic collisions between the laser-cooled ions and virtual very light atoms. This combined method quickly achieves the quasiequilibrium state of large mixed Coulomb crystals with over 103 ions, regardless of the initial conditions, and shows that the previously used pseudopotential-based adiabatic approximations should be replaced by such molecular-dynamics simulations. In addition, a pattern-matching recognition procedure is introduced which objectively ascertains the number of ions. We also apply the presented characterization method to determine the reaction-rate constant between slow acetonitrile molecules and sympathetically cooled Ne+ ions at a translational temperature lower than 10 K.

  9. Coulomb interaction effects on the Majorana states in quantum wires.

    PubMed

    Manolescu, A; Marinescu, D C; Stanescu, T D

    2014-04-30

    The stability of the Majorana modes in the presence of a repulsive interaction is studied in the standard semiconductor wire-metallic superconductor configuration. The effects of short-range Coulomb interaction, which is incorporated using a purely repulsive δ-function to model the strong screening effect due to the presence of the superconductor, are determined within a Hartree-Fock approximation of the effective Bogoliubov-De Gennes Hamiltonian that describes the low-energy physics of the wire. Through a numerical diagonalization procedure we obtain interaction corrections to the single particle eigenstates and calculate the extended topological phase diagram in terms of the chemical potential and the Zeeman energy. We find that, for a fixed Zeeman energy, the interaction shifts the phase boundaries to a higher chemical potential, whereas for a fixed chemical potential this shift can occur either at lower or higher Zeeman energies. These effects can be interpreted as a renormalization of the g-factor due to the interaction. The minimum Zeeman energy needed to realize Majorana fermions decreases with the increasing strength of the Coulomb repulsion. Furthermore, we find that in wires with multi-band occupancy this effect can be enhanced by increasing the chemical potential, i.e. by occupying higher energy bands. PMID:24722427

  10. Coulomb-corrected molecular orbital tomography of nitrogen

    NASA Astrophysics Data System (ADS)

    Zhai, Chunyang; He, Lixin; Lan, Pengfei; Zhu, Xiaosong; Li, Yang; Wang, Feng; Shi, Wenjing; Zhang, Qingbin; Lu, Peixiang

    2016-03-01

    High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, the photon energy is usually no more than 100 eV in HHG. In this work, we experimentally reconstruct the highest occupied molecular orbital (HOMO) of nitrogen (N2) by using a Coulomb-corrected MOT (CCMOT) method. In our scheme, the molecular continuum states are described by a Coulomb wave function instead of the PW approximation. With CCMOT, the reconstructed orbital is demonstrated to agree well with the theoretical prediction and retain the main features of the HOMO of N2. Compared to the PW approximation method, the CCMOT shows a significant improvement in eliminating the artificial structures caused by PW approximation.

  11. Coulomb-corrected molecular orbital tomography of nitrogen.

    PubMed

    Zhai, Chunyang; He, Lixin; Lan, Pengfei; Zhu, Xiaosong; Li, Yang; Wang, Feng; Shi, Wenjing; Zhang, Qingbin; Lu, Peixiang

    2016-01-01

    High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, the photon energy is usually no more than 100 eV in HHG. In this work, we experimentally reconstruct the highest occupied molecular orbital (HOMO) of nitrogen (N2) by using a Coulomb-corrected MOT (CCMOT) method. In our scheme, the molecular continuum states are described by a Coulomb wave function instead of the PW approximation. With CCMOT, the reconstructed orbital is demonstrated to agree well with the theoretical prediction and retain the main features of the HOMO of N2. Compared to the PW approximation method, the CCMOT shows a significant improvement in eliminating the artificial structures caused by PW approximation. PMID:27000666

  12. Enhancement of the Coulomb collision rate by individual particle wakes

    NASA Astrophysics Data System (ADS)

    Baalrud, Scott; Scheiner, Brett

    2013-09-01

    Charged particles moving in a plasma leave a trailing wake in their electric potential profile associated with the response function of the medium. For superthermal particles, these wakes can cause significant departures from the oft-assumed screened Coulomb potential profile. The wakes extend the interaction length scale beyond the Debye screening length for collisions between fast test particles and field particles in their wake. This can increase the Coulomb collision rate for velocities beyond the thermal speed. To demonstrate this effect, we consider the relaxation rate due to electron-electron collisions of an electron distribution function with initially depleted tails, as is common near boundary sheaths or double layers. This problem is related to Langmuir's paradox. We compare the standard Landau (Fokker-Planck) collision operator, which does not account for wakes, with the Lenard-Balescu collision operator, which includes wake effects through the linear dielectric response function. For this distribution, the linear dielectric is described by the incomplete plasma dispersion function. We compare the collision operators directly as well as the relaxation rate determined from a hybrid kinetic-fluid model. S. D. Baalrud, Phys. Plasmas 20, 012118 (2013).

  13. Coulomb excitation of 44Ca and 46Ar

    NASA Astrophysics Data System (ADS)

    Calinescu, S.; Cáceres, L.; Grévy, S.; Sorlin, O.; Dombrádi, Z.; Stanoiu, M.; Astabatyan, R.; Borcea, C.; Borcea, R.; Bowry, M.; Catford, W.; Clément, E.; Franchoo, S.; Garcia, R.; Gillibert, R.; Guerin, I. H.; Kuti, I.; Lukyanov, S.; Lepailleur, A.; Maslov, V.; Morfouace, P.; Mrazek, J.; Negoita, F.; Niikura, M.; Perrot, L.; Podolyák, Z.; Petrone, C.; Penionzhkevich, Y.; Roger, T.; Rotaru, F.; Sohler, D.; Stefan, I.; Thomas, J. C.; Vajta, Z.; Wilson, E.

    2016-04-01

    The reduced transition probabilities B (E 2 ;0g.s . +→21+) of the 46Ar and 44Ca nuclei were studied using the Coulomb excitation technique at intermediate energy at the LISE/GANIL facility. The in-flight γ rays, emitted after the Coulomb excitation of their first 2+ states, were detected in an array of 64 BaF2 crystals. The present B(E 2 ↑ ) value for 44Ca, 475(36) e2fm4 , agrees well with the value of 495(35) e2fm4 obtained by averaging results of previous experiments. Consistent B (E 2 ;0g.s . +→21+) values of 225(29) e2fm4 and 234(19) e2fm4 have been obtained for 46Ar from an absolute and a relative measurement, normalized to the 44Ca value. Both results agree with the ones obtained with the same experimental technique at the NSCL facility but are a factor of 2 smaller than the shell model predictions. The drop in B (E 2 ;0g.s . +→21+) in the Ar chain at N =28 , confirmed in this experiment, shows that 46Ar is sensitive to the N =28 shell closure.

  14. Pore fluid pressure, apparent friction, and Coulomb failure

    USGS Publications Warehouse

    Beeler, N.M.; Simpson, R.W.; Hickman, S.H.; Lockner, D.A.

    2000-01-01

    Many recent studies of stress-triggered seismicity rely on a fault failure model with a single free parameter, the apparent coefficient of friction, presumed to be a material constant with possible values 0 ≤ μ′ ≤ 1. These studies may present a misleading view of fault strength and the role of pore fluid pressure in earthquake failure. The parameter μ′ is intended to incorporate the effects of both friction and pore pressure, but is a material constant only if changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the potential failure plane. Although specific models of fault zones permit such a relation, neither is it known that fault zones within the Earth behave this way, nor is this behavior expected in all cases. In contrast, for an isotropic homogeneous poroelastic model the pore pressure changes are proportional to changes in mean stress, μ′ is not a material constant, and −∞ ≤ μ′ ≤ +∞. Analysis of the change in Coulomb failure stress for tectonically loaded reverse and strike-slip faults shows considerable differences between these two pore pressure models, suggesting that such models might be distinguished from one another using observations of triggered seismicity (e.g., aftershocks). We conclude that using the constant apparent friction model exclusively in studies of Coulomb failure stress is unwise and could lead to significant errors in estimated stress change and seismic hazard.

  15. Coulomb excitation of a {sup 78}Rb radioactive beam.

    SciTech Connect

    Schwartz, J.

    1998-11-18

    In order to test the feasibility of Coulomb excitation of radioactive projectiles with low beam energies and intensities, they have produced a secondary radioactive beam of {sup 78}Rb and Coulomb re-excited it. The beam was produced in the fusion evaporation reaction {sup 24}Mg({sup 58}Ni,3pn){sup 78}Rb at a beam energy of 260 MeV, using the Argonne National Laboratory ATLAS accelerator. The residues of interest were separated from other reaction products and non-interacting beam using the Fragment Mass Analyzer (FMA). The beam leaving the FMA was {sup 78}Kr and {sup 78}Rb{sup gs,m1,m2}, which was refocused onto a {sup 58}Ni secondary target. They have extracted a spectrum of {gamma}-rays associated with re-excitation of A = 78 isobars. The re-excitation of stable {sup 78}Kr was observed, which serves as a reference. Gamma-rays associated with excitation of {sup 78}Rb{sup gs,m1,m2} were also seen. The measured yields indicate that all the {sup 78}Rb states are highly deformed.

  16. Coulomb attraction in the optical spectra of quantum disks

    NASA Astrophysics Data System (ADS)

    Adolph, B.; Glutsch, S.; Bechstedt, F.

    1993-11-01

    In this paper we present a theory that describes the influence of the Coulomb interaction between electrons and holes on the optical spectra of flat quantum dots within the envelope-function formalism. Starting from a nonlocal Elliott-like formula, absorption and luminescence characteristics are traced back to properties of two-particle wave functions and energies, which are solutions of the corresponding Schrödinger equation for an electron-hole pair under the influence of the Coulomb attraction and confinement potentials, determined by the spatial variation of the band edges of the considered microstructure. We present a complete numerical solution of the two-particle problem for flat quantum dots, i.e., disks for which the size quantization in the growth direction is much stronger than that in the perpendicular plane. The resulting theoretical line shapes are compared with luminescence spectra obtained recently for quantum dots fabricated by laser-induced thermal cation interdiffusion in quantum-well structures.

  17. Mechanical model of the Lorentz force and Coulomb interaction

    NASA Astrophysics Data System (ADS)

    Dmitriyev, Valery

    2008-09-01

    The centripetal and Coriolis accelerations experienced by a cart traveling over a rotating turntable are usually calculated proceeding from the known kinematics of the problem. Respective forces can be regarded as due to the entrainment of the cart in the moving solid environs. We extend the approach to the general case of a particle entrained in the flow of the surrounding medium. The expression for the driving force on the particle obtained from the kinematics of the entrainment prescribed appears to be isomorphic to the Lorentz and Coulomb force on a positive electric charge. The inverse direction of the electromagnetic force on a negative charge implies that a growing applied flow induces the upstream motion of the particle. A possible microscopic mechanism for it may be the Magnus force dynamics of a kink in a vortex tangle. The loop on a straight vortex filament can be taken as a model of the electron, the loop with a cavitation models the positron. The Lorentz force is concerned with the Coriolis acceleration. The Coulomb interaction is due to the centripetal or centrifugal force that arises in the turbophoresis of the kink in the perturbation field generated in the medium by the center of pressure.

  18. Exact linearized Coulomb collision operator in the moment expansion

    DOE PAGESBeta

    Ji, Jeong -Young; Held, Eric D.

    2006-10-05

    In the moment expansion, the Rosenbluth potentials, the linearized Coulomb collision operators, and the moments of the collision operators are analytically calculated for any moment. The explicit calculation of Rosenbluth potentials converts the integro-differential form of the Coulomb collision operator into a differential operator, which enables one to express the collision operator in a simple closed form for any arbitrary mass and temperature ratios. In addition, it is shown that gyrophase averaging the collision operator acting on arbitrary distribution functions is the same as the collision operator acting on the corresponding gyrophase averaged distribution functions. The moments of the collisionmore » operator are linear combinations of the fluid moments with collision coefficients parametrized by mass and temperature ratios. Furthermore, useful forms involving the small mass-ratio approximation are easily found since the collision operators and their moments are expressed in terms of the mass ratio. As an application, the general moment equations are explicitly written and the higher order heat flux equation is derived.« less

  19. Unsafe coulomb excitation of {sup 240-244}Pu.

    SciTech Connect

    Wiedenhoever, I.

    1998-12-01

    The high spin states of {sup 240}Pu and {sup 244}Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a {sup 208}Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to {sup 242}Pu were obtained as well. In the case of {sup 244}Pu, the yrast band was extended to 34{h_bar}, revealing the completed {pi}i{sub 13/2} alignment, a ''first'' for actinide nuclei. The yrast sequence of {sup 242}Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of {sup 240}Pu was measured up to the highest rotational frequencies ever reported in the actinide region ({approximately} 300 keV), no sign of particle alignment was observed. In this case, several observables such as the large B(E1)/B(E2) branching ratios in the negative parity band, and the vanishing energy staggering between the negative and positive parity bands suggest that the strength of octupole correlations increases with rotational frequency. These stronger correlations may well be responsible for delaying or suppressing the {pi}i{sub 13/2} particle alignment.

  20. Coulomb-corrected molecular orbital tomography of nitrogen

    PubMed Central

    Zhai, Chunyang; He, Lixin; Lan, Pengfei; Zhu, Xiaosong; Li, Yang; Wang, Feng; Shi, Wenjing; Zhang, Qingbin; Lu, Peixiang

    2016-01-01

    High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, the photon energy is usually no more than 100 eV in HHG. In this work, we experimentally reconstruct the highest occupied molecular orbital (HOMO) of nitrogen (N2) by using a Coulomb-corrected MOT (CCMOT) method. In our scheme, the molecular continuum states are described by a Coulomb wave function instead of the PW approximation. With CCMOT, the reconstructed orbital is demonstrated to agree well with the theoretical prediction and retain the main features of the HOMO of N2. Compared to the PW approximation method, the CCMOT shows a significant improvement in eliminating the artificial structures caused by PW approximation. PMID:27000666

  1. "Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications

    NASA Astrophysics Data System (ADS)

    Marshall, J. R.

    1999-09-01

    The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this

  2. "Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications

    NASA Technical Reports Server (NTRS)

    Marshall, J. R.

    1999-01-01

    The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this

  3. Reading Transformation

    ERIC Educational Resources Information Center

    Reeves, Melinda

    2006-01-01

    The parents of students who attend Decatur High School thought that there was little hope of their kids going on to college. After a year or so in Decatur's reading program, their sons and daughters were both transformed and college bound. In this article, the author describes how Decatur was able to successfully transform their students. Seven…

  4. Spin Hamiltonian, order out of a Coulomb phase, and pseudocriticality in the frustrated pyrochlore Heisenberg antiferromagnet FeF3

    NASA Astrophysics Data System (ADS)

    Sadeghi, Azam; Alaei, Mojtaba; Shahbazi, Farhad; Gingras, Michel J. P.

    2015-04-01

    FeF3, with its half-filled Fe3 +3 d orbital, hence zero orbital angular momentum and S =5 /2 , is often put forward as a prototypical highly frustrated classical Heisenberg pyrochlore antiferromagnet. By employing ab initio density functional theory, we obtain an effective spin Hamiltonian for this material. This Hamiltonian contains nearest-neighbor antiferromagnetic Heisenberg, biquadratic, and Dzyaloshinskii-Moriya interactions as dominant terms and we use Monte Carlo simulations to investigate the nonzero temperature properties of this minimal model. We find that upon decreasing temperature, the system passes through a Coulomb phase, composed of short-range correlated coplanar states, before transforming into an "all-in/all-out" (AIAO) state via a very weakly first-order transition at a critical temperature Tc≈22 K, in good agreement with the experimental value for a reasonable set of Coulomb interaction U and Hund's coupling JH describing the material. Despite the transition being first order, the AIAO order parameter evolves below Tc with a power-law behavior characterized by a pseudo "critical exponent" β ≈0.18 in accord with experiment. We comment on the origin of this unusual β value.

  5. Short-time dynamics of correlated quantum Coulomb systems

    NASA Astrophysics Data System (ADS)

    Bonitz, Michael

    2007-03-01

    Strong correlations in dense Coulomb systems are attracting increasing interest in many fields ranging from dense astrophysical plasmas, dusty plasmas and semiconductors to metal clusters and ultracold trapped ions [1]. Examples are bound states in dense plasmas (atoms, molecules, clusters) and semiconductors (excitons, trions, biexcitons) and many-particle correlations such as Coulomb and Yukawa liquids and crystals. Of particular current interest is the response of these systems to short excitations generated e.g. by femtosecond laser pulses and giving rise to ultrafast relaxation processes and build up of binary correlations. The proper theoretical tool are non-Markovian quantum kinetic equations [1,2] which can be derived from Nonequilibrium Green's Functions (NEGF) and are now successfully solved numerically for dense plasmas and semiconductors [3], correlated electrons [4] and other many-body systems with moderate correlations [5]. This method is well suited to compute the nonlinear response to strong fields selfconsistently including many-body effects [6]. Finally, we discuss recent extensions of the NEGF-computations to the dynamics of strongly correlated Coulomb systems, such as single atoms and molecules [7] and electron and exciton Wigner crystals in quantum dots [8,9]. [1] H. Haug and A.-P. Jauho, Quantum Kinetics in Transport and Optics of Semiconductors, Springer 1996; M. Bonitz Quantum Kinetic Theory, Teubner, Stuttgart/Leipzig 1998; [2] Progress in Nonequilibrium Green's Functions III, M. Bonitz and A. Filinov (Eds.), J. Phys. Conf. Ser. vol. 35 (2006); [3] M. Bonitz et al. Journal of Physics: Condensed Matter 8, 6057 (1996); R. Binder, H.S. K"ohler, and M. Bonitz, Phys. Rev. B 55, 5110 (1997); [4] N.H. Kwong, and M. Bonitz, Phys. Rev. Lett. 84, 1768 (2000); [5] Introduction to Computational Methods for Many-Body Systems, M. Bonitz and D. Semkat (eds.), Rinton Press, Princeton (2006); [6] H. Haberland, M. Bonitz, and D. Kremp, Phys. Rev. E 64

  6. Confluent Heun equations: convergence of solutions in series of coulomb wavefunctions

    NASA Astrophysics Data System (ADS)

    Jaccoud El-Jaick, Léa; Figueiredo, Bartolomeu D. B.

    2013-03-01

    The Leaver solutions in series of Coulomb wavefunctions for the confluent Heun equation are given by two-sided infinite series, that is, by series where the summation index n runs from minus to plus infinity (Leaver 1986 J. Math. Phys.27 1238). First we show that, in contrast to the D’Alembert test, under certain conditions the Raabe test ensures that the domains of convergence of these solutions include an additional singular point. We also consider solutions for a limit of the confluent Heun equation. For both equations, new solutions are generated by transformations of variables. Finally, we discuss the time dependence of the Klein-Gordon equation in two cosmological models and the spatial dependence of the Schrödinger equation to a family of quasi-exactly solvable potentials. For a subfamily of these potentials, we obtain infinite-series solutions which converge and are bounded for all values of the independent variable, in opposition to a common belief.

  7. Three-body Coulomb systems using generalized angular-momentum S states

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Sims, J. S.

    1974-01-01

    An expansion of the three-body Coulomb potential in generalized angular-momentum eigenfunctions developed earlier by one of the authors is used to compute energy eigenvalues and eigenfunctions of bound S states of three-body Coulomb systems. The results for He, H(-), e(-)e(+)e(-), and pmu(-)p are compared with the results of other computational approaches.

  8. Addendum to 'Equation of state of classical Coulomb plasma mixtures'

    SciTech Connect

    Potekhin, A. Y.; Chabrier, G.; Chugunov, A. I.; DeWitt, H. E.; Rogers, F. J.

    2009-10-15

    Recently developed analytic approximation for the equation of state of fully ionized nonideal electron-ion plasma mixtures [A. Y. Potekhin, G. Chabrier, and F. J. Rogers, Phys. Rev. E 79, 016411 (2009)], which covers the transition between the weak and strong Coulomb coupling regimes and reproduces numerical results obtained in the hypernetted-chain (HNC) approximation, is modified in order to fit the small deviations from the linear mixing in the strong-coupling regime, revealed by recent Monte Carlo simulations. In addition, a mixing rule is proposed for the regime of weak coupling, which generalizes post-Debye density corrections to the case of mixtures and numerically agrees with the HNC approximation in that regime.

  9. Investigation of uncertainty components in Coulomb blockade thermometry

    SciTech Connect

    Hahtela, O. M.; Heinonen, M.; Manninen, A.; Meschke, M.; Savin, A.; Pekola, J. P.; Gunnarsson, D.; Prunnila, M.; Penttilä, J. S.; Roschier, L.

    2013-09-11

    Coulomb blockade thermometry (CBT) has proven to be a feasible method for primary thermometry in every day laboratory use at cryogenic temperatures from ca. 10 mK to a few tens of kelvins. The operation of CBT is based on single electron charging effects in normal metal tunnel junctions. In this paper, we discuss the typical error sources and uncertainty components that limit the present absolute accuracy of the CBT measurements to the level of about 1 % in the optimum temperature range. Identifying the influence of different uncertainty sources is a good starting point for improving the measurement accuracy to the level that would allow the CBT to be more widely used in high-precision low temperature metrological applications and for realizing thermodynamic temperature in accordance to the upcoming new definition of kelvin.

  10. Coulomb collisions and coronal heating by velocity filtration

    NASA Astrophysics Data System (ADS)

    Anderson, Stephen W.

    1994-12-01

    We introduce the effects of Coulomb collisions to the velocity filtration model of coronal heating, which has so far been done collisionlessly. Non-Maxwellian particle distributions are at the heart of this model, so collisions, which force such distributions to relax, can play a critical role. We consider a column of plasma extending upwards from the bottom of the corona and use typical transition zone densities and temperatures as well as the non-Maxwellian kappa distribution previously used in this model. We demonstrate the collisions are an important factor by comparing electron density and energy profiles predicted by the collisionless Vlasov equation to ones made using the assumption that collisions are a small, first-order perturbation. For the heights considered (below 0.5 solar radius), these collisional corrections are of order unity or larger. We conclude that the velocity filtration model needs to be redone including collisions self-consistently.

  11. Coulomb and nuclear excitations of narrow resonances in 17Ne

    NASA Astrophysics Data System (ADS)

    Marganiec, J.; Wamers, F.; Aksouh, F.; Aksyutina, Yu.; Álvarez-Pol, H.; Aumann, T.; Beceiro-Novo, S.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Chartier, M.; Chatillon, A.; Chulkov, L. V.; Cortina-Gil, D.; Emling, H.; Ershova, O.; Fraile, L. M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Heil, M.; Hoffmann, D. H. H.; Hoffmann, J.; Johansson, H. T.; Jonson, B.; Karagiannis, C.; Kiselev, O. A.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Langer, C.; Lantz, M.; Le Bleis, T.; Lemmon, R.; Litvinov, Yu. A.; Mahata, K.; Müntz, C.; Nilsson, T.; Nociforo, C.; Nyman, G.; Ott, W.; Panin, V.; Paschalis, S.; Perea, A.; Plag, R.; Reifarth, R.; Richter, A.; Rodriguez-Tajes, C.; Rossi, D.; Riisager, K.; Savran, D.; Schrieder, G.; Simon, H.; Stroth, J.; Sümmerer, K.; Tengblad, O.; Typel, S.; Weick, H.; Wiescher, M.; Wimmer, C.

    2016-08-01

    New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the 15O + p + p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

  12. Coulomb-stable triply charged diatomic: HeY3+

    NASA Astrophysics Data System (ADS)

    Wesendrup, Ralf; Pernpointner, Markus; Schwerdtfeger, Peter

    1999-11-01

    Accurate relativistic coupled-cluster calculations show that the triply charged species HeY3+ is a stable molecule and represents the lightest diatomic trication that does not undergo a Coulomb fragmentation into charged fragments. The diatomic potential-energy curve is approximated by an extended Morse potential, and vibrational-rotational constants for HeY3+ are predicted (Re=224.3 pm, D0=0.394 eV, ωe=437 cm-1, ωexe=15.8 cm-1, Be=0.877 cm-1). It is further shown that the He-Y3+ bond can basically be described as a charge-induced dipole interaction.

  13. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices.

    PubMed

    Lotkhov, Sergey V

    2013-06-14

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ~ 20 mK for films with sheet resistivities as high as ~7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current. PMID:23670293

  14. Gravitational Modification of the Coulomb-Breit Hamiltonian

    SciTech Connect

    Caicedo, Jose Alexander; Urrutia, Luis Fernando

    2009-04-20

    In the poster session we presented a short review of our first results in the construction of the Coulomb-Breit Hamiltonian for a pair of fermions immersed in a background gravitational field which is described by General Relativity. Here we present a resume of that construction. We make a special stress on the objectives and the hypothesis used, but there is no special attention on the explicit form of the results because actually there is an updated and optimised version of our work in the edition process for publication; however we mention some special characteristics of the effect of the background gravitational field on the quantum nature of the system composed by fermions and its electromagnetic field, particularly the possibility of the observation of centre of mass effects in matter interferometry experiments.

  15. Highly accurate eigenvalues for the distorted Coulomb potential

    NASA Astrophysics Data System (ADS)

    Ixaru, L. Gr.; de Meyer, H.; vanden Berghe, G.

    2000-03-01

    We consider the eigenvalue problem for the radial Schrödinger equation with potentials of the form V(r)=S(r)/r+R(r) where S(r) and R(r) are well behaved functions which tend to some (not necessarily equal) constants when r-->0 and r-->∞. Formulas (14.4.5)-(14.4.8) of Abramowitz and Stegun [Handbook of Mathematical Functions, 8th ed. (Dover, New York, 1972)], corresponding to the pure Coulomb case, are here generalized for this distorted case. We also present a complete procedure for the numerical solution of the problem. Our procedure is robust, very economic and particularly suited for very large n. Numerical illustrations for n up to 2000 are given.

  16. Interatomic Coulombic decay widths of helium trimer: Ab initio calculations

    SciTech Connect

    Kolorenč, Přemysl; Sisourat, Nicolas

    2015-12-14

    We report on an extensive study of interatomic Coulombic decay (ICD) widths in helium trimer computed using a fully ab initio method based on the Fano theory of resonances. Algebraic diagrammatic construction for one-particle Green’s function is utilized for the solution of the many-electron problem. An advanced and universal approach to partitioning of the configuration space into discrete states and continuum subspaces is described and employed. Total decay widths are presented for all ICD-active states of the trimer characterized by one-site ionization and additional excitation of an electron into the second shell. Selected partial decay widths are analyzed in detail, showing how three-body effects can qualitatively change the character of certain relaxation transitions. Previously unreported type of three-electron decay processes is identified in one class of the metastable states.

  17. Interatomic Coulombic decay widths of helium trimer: Ab initio calculations.

    PubMed

    Kolorenč, Přemysl; Sisourat, Nicolas

    2015-12-14

    We report on an extensive study of interatomic Coulombic decay (ICD) widths in helium trimer computed using a fully ab initio method based on the Fano theory of resonances. Algebraic diagrammatic construction for one-particle Green's function is utilized for the solution of the many-electron problem. An advanced and universal approach to partitioning of the configuration space into discrete states and continuum subspaces is described and employed. Total decay widths are presented for all ICD-active states of the trimer characterized by one-site ionization and additional excitation of an electron into the second shell. Selected partial decay widths are analyzed in detail, showing how three-body effects can qualitatively change the character of certain relaxation transitions. Previously unreported type of three-electron decay processes is identified in one class of the metastable states. PMID:26671378

  18. Coulomb interaction effect in tilted Weyl fermion in two dimensions

    NASA Astrophysics Data System (ADS)

    Isobe, Hiroki; Nagaosa, Naoto

    Weyl fermions with tilted linear dispersions characterized by several different velocities appear in some systems including the quasi-two-dimensional organic semiconductor α-(BEDT-TTF)2I3 and three-dimensional WTe2. The Coulomb interaction between electrons modifies the velocities in an essential way in the low energy limit, where the logarithmic corrections dominate. Taking into account the coupling to both the transverse and longitudinal electromagnetic fields, we derive the renormalization group equations for the velocities of the tilted Weyl fermions in two dimensions, and found that they increase as the energy decreases and eventually hit the velocity of light c to result in the Cherenkov radiation. Especially, the system restores the isotropic Weyl cone even when the bare Weyl cone is strongly tilted and the velocity of electrons becomes negative in certain directions.

  19. Deep inelastic scattering at energies near the Coulomb barrier

    SciTech Connect

    Gehring, J.; Rehm, K.E.; Schiffer, J.P.

    1993-10-01

    A large yield for a process that appears to have many of the features of deep inelastic scattering has been observed at energies, near the Coulomb barrier in the systems {sup 112,124}Sn + {sup 58}Ni by Wolfs et al. In order to better understand the mechanisms by which energy dissipation takes place close to the barrier, we have extended the measurements of Wolfs to the system {sup 136}Xe + {sup 64}Ni. The use of inverse kinematics in the present measurements resulted in better mass and energy resolution due to reduced target effects and in more complete angular coverage. We have obtained angular distributions, mass distributions, and total cross sections for deep inelastic scattering at two energies near the barrier. The results on the closed neutron shell nucleus {sup 136}Xe complement those from the closed proton shell Sn nuclei.

  20. Bounded solutions of neutral fermions with a screened Coulomb potential

    SciTech Connect

    Castro, Antonio S. de . E-mail: castro@feg.unesp.br

    2005-11-01

    The intrinsically relativistic problem of a fermion subject to a pseudoscalar screened Coulomb plus a uniform background potential in two-dimensional space-time is mapped into a Sturm-Liouville. This mapping gives rise to an effective Morse-like potential and exact bounded solutions are found. It is shown that the uniform background potential determinates the number of bound-state solutions. The behaviour of the eigenenergies as well as of the upper and lower components of the Dirac spinor corresponding to bounded solutions is discussed in detail and some unusual results are revealed. An apparent paradox concerning the uncertainty principle is solved by recurring to the concepts of effective mass and effective Compton wavelength.

  1. Communication: Phase space wavelets for solving Coulomb problems.

    PubMed

    Shimshovitz, Asaf; Tannor, David J

    2012-09-14

    Recently we introduced a phase space approach for solving the time-independent Schrödinger equation using a periodic von Neumann basis with bi-orthogonal exchange (pvb) [A. Shimshovitz and D. J. Tannor, Phys. Rev. Lett. 109, 070402 (2012)]. Here we extend the approach to allow a wavelet scaling of the phase space Gaussians. The new basis set, which we call the wavelet pvb basis, is simple to implement and provides an appealing alternative to other wavelet approaches. For the 1D Coulomb problems tested in this paper, the method reduces the size of the basis relative to the Fourier grid method by a factor of 13-60. The savings in basis set size is predicted to grow steeply as the dimensionality increases. PMID:22979843

  2. Influence of Coulomb screening on lateral lasing in VECSELs.

    PubMed

    Wang, Chengao; Malloy, Kevin; Sheik-Bahae, Mansoor

    2015-12-14

    Parasitic lateral lasing in certain optically pumped semiconductor disc lasers drains the gain of the vertical mode and thus causes power scaling degradation and premature rollover in surface emitting operation. We have observed this effect in both multiple quantum wells (MQW) (GaInAs/GaAs) and double heterostructures (DHS) (GaInP/GaAs/GaInP) under pulsed excitation even when the gain chip lateral dimensions are much larger than the diameter of the pump laser. Lateral lasing occurs persistently between cleaved facets at a band-tail wavelength much longer than the peak of the gain. We show that the effect of bandgap renormalization due to Coulomb screening explains this phenomena. Exploiting the simple analytical plasma theory of bulk semiconductors (Banyai & Koch, 1986), we can account for such an effect in double heterostructures. PMID:26699044

  3. Coulomb Screening and Coherent Phonon in Methylammonium Lead Iodide Perovskites.

    PubMed

    Wang, He; Valkunas, Leonas; Cao, Thu; Whittaker-Brooks, Luisa; Fleming, Graham R

    2016-08-18

    Methylammonium lead iodide (CH3NH3PbI3) hybrid perovskite in the tetragonal and orthorhombic phases have different exciton binding energies and demonstrate different excitation kinetics. Here, we explore the role that crystal structure plays in the kinetics via fluence dependent transient absorption spectroscopy. We observe stronger saturation of the free carrier concentration under high pump energy density in the orthorhombic phase relative to the tetragonal phase. We attribute this phenomenon to small dielectric constant, large exciton binding energy, and weak Coulomb screening, which results in difficult exciton dissociation under high light intensity in the orthorhombic phase. At higher excitation intensities, we observe a coherent phonon with an oscillation frequency of 23.4 cm(-1) at 77 K, whose amplitude tracks the increase of the first-order lifetime. PMID:27485190

  4. Attractive Coulomb interaction of two-dimensional Rydberg excitons

    NASA Astrophysics Data System (ADS)

    Shahnazaryan, V.; Shelykh, I. A.; Kyriienko, O.

    2016-06-01

    We analyze theoretically the Coulomb scattering processes of highly excited excitons in the direct-band-gap semiconductor quantum wells. We find that contrary to the interaction of ground-state excitons, the electron and hole exchange interaction between excited excitons has an attractive character both for s - and p -type two-dimensional (2D) excitons. Moreover, we show that similar to the three-dimensional highly excited excitons, the direct interaction of 2D Rydberg excitons exhibits van der Waals-type long-range interaction. The results predict the linear growth of the absolute value of exchange interaction strength with an exciton principal quantum number and point the way towards enhancement of optical nonlinearity in 2D excitonic systems.

  5. Coulomb blockade in low-mobility nanometer size Si MOSFET's

    NASA Astrophysics Data System (ADS)

    Sanquer, M.; Specht, M.; Ghenim, L.; Deleonibus, S.; Guegan, G.

    2000-03-01

    We investigate coherent transport in Si metal-oxide-semiconductor field-effect transistors with nominal gate lengths 50-100 nm and various widths at very low temperature. Independent of the geometry, localized states appear when G~=e2/h and transport is dominated by resonant tunnelling through a single quantum dot formed by an impurity potential. We find that the typical size of the relevant impurity quantum dot is comparable to the channel length and that the periodicity of the observed Coulomb blockade oscillations is roughly inversely proportional to the channel length. The spectrum of resonances and the nonlinear I-V curves allow us to measure the charging energy and the mean level energy spacing for electrons in the localized state. Furthermore, we find that in the dielectric regime the variance var(lng) of the logarithmic conductance lng is proportional to its average value consistent with one-electron scaling models.

  6. Coulomb gauge confinement in the heavy quark limit

    SciTech Connect

    Popovici, C.; Watson, P.; Reinhardt, H.

    2010-05-15

    The relationship between the nonperturbative Green's functions of Yang-Mills theory and the confinement potential is investigated. By rewriting the generating functional of quantum chromodynamics in terms of a heavy quark mass expansion in Coulomb gauge, restricting to leading order in this expansion and considering only the two-point functions of the Yang-Mills sector, the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is shown to be exact in this case and an analytic, nonperturbative solution is presented. It is found that there is a direct connection between the string tension and the temporal gluon propagator. Further, it is shown that for the 4-point quark correlation functions, only confined bound states of color-singlet quark-antiquark (meson) and quark-quark (baryon) pairs exist.

  7. Strong nuclear couplings as a source of Coulomb rainbow suppression

    SciTech Connect

    Keeley, N.; Alamanos, N.; Rusek, K.

    2010-09-15

    A recent measurement of the {sup 11}Be+{sup 64}Zn quasielastic scattering angular distribution exhibits a non-Fresnel-type pattern, in contrast to {sup 6}He+{sup 64}Zn elastic scattering but similar to that for the elastic scattering of {sup 6}He from heavy targets. We show by means of continuum discretized coupled-channels (CDCC) calculations that this unusual behavior of {sup 11}Be is caused by the much greater importance of nuclear coupling to the continuum in {sup 11}Be compared to {sup 6}He, where Coulomb dipole coupling is mainly responsible for the non-Fresnel-like shape, when present. We also show that the dynamic polarization potentials derived from the CDCC calculations seem to follow a universal form as a function of radius.

  8. Dynamic stresses, coulomb failure, and remote triggering: corrected

    USGS Publications Warehouse

    Hill, David P.

    2012-01-01

    Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes <1  MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid‐onset triggered seismicity that develop during the surface‐wave peak dynamic stressing. Evaluation of the triggering potential of surface‐wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love‐wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid‐onset dynamic triggering may not reside solely with a simple static‐threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20‐s Rayleigh‐wave stresses than thrust faults in the shallow seismogenic crust (<10  km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde‐to‐prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh‐wave dynamic stresses than compressional or transpressional regimes.

  9. Coulomb problem in non-commutative quantum mechanics

    SciTech Connect

    Galikova, Veronika; Presnajder, Peter

    2013-05-15

    The aim of this paper is to find out how it would be possible for space non-commutativity (NC) to alter the quantum mechanics (QM) solution of the Coulomb problem. The NC parameter {lambda} is to be regarded as a measure of the non-commutativity - setting {lambda}= 0 which means a return to the standard quantum mechanics. As the very first step a rotationally invariant NC space R{sub {lambda}}{sup 3}, an analog of the Coulomb problem configuration space (R{sup 3} with the origin excluded) is introduced. R{sub {lambda}}{sup 3} is generated by NC coordinates realized as operators acting in an auxiliary (Fock) space F. The properly weighted Hilbert-Schmidt operators in F form H{sub {lambda}}, a NC analog of the Hilbert space of the wave functions. We will refer to them as 'wave functions' also in the NC case. The definition of a NC analog of the hamiltonian as a hermitian operator in H{sub {lambda}} is one of the key parts of this paper. The resulting problem is exactly solvable. The full solution is provided, including formulas for the bound states for E < 0 and low-energy scattering for E > 0 (both containing NC corrections analytic in {lambda}) and also formulas for high-energy scattering and unexpected bound states at ultra-high energy (both containing NC corrections singular in {lambda}). All the NC contributions to the known QM solutions either vanish or disappear in the limit {lambda}{yields} 0.

  10. Lightweight transformer

    SciTech Connect

    Swallom, D.W.; Enos, G.

    1990-05-01

    The technical effort described in this report relates to the program that was performed to design, fabricate, and test a lightweight transformer for Strategic Defense Initiative Organization (SDIO) mission requirements. The objectives of this program were two-fold: (1) design and fabricate a lightweight transformer using liquid hydrogen as the coolant; and (2) test the completed transformer assembly with a low voltage, dc power source. Although the full power testing with liquid helium was not completed, the program demonstrated the viability of the design approach. The lightweight transformer was designed and fabricated, and low and moderate power testing was completed. The transformer is a liquid hydrogen cooled air core transformer that uses thin copper for its primary and secondary windings. The winding mass was approximately 12 kg, or 0.03 kg/kW. Further refinements of the design to a partial air core transformer could potentially reduce the winding mass to as low as 4 or 5 kg, or 0.0125 kg/kW. No attempt was made on this program to reduce the mass of the related structural components or cryogenic container. 8 refs., 39 figs., 2 tabs.

  11. Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials

    SciTech Connect

    Roy Chowdhury, Dibakar; Xu, Ningning; Zhang, Weili; Singh, Ranjan

    2015-07-14

    Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials.

  12. Coulomb collisions in the Boltzmann equation for electrons in low-temperature gas discharge plasmas

    NASA Astrophysics Data System (ADS)

    Hagelaar, G. J. M.

    2016-02-01

    This paper investigates the effects of electron-electron and electron-ion Coulomb collisions on the electron distribution function and transport coefficients obtained from the Boltzmann equation for simple dc gas discharge conditions. Expressions are provided for the full Coulomb collision terms acting on both the isotropic and anisotropic parts of the electron distribution function, which are then incorporated in the freeware Boltzmann equation solver BOLSIG+. Different Coulomb collision effects are demonstrated and discussed on the basis of BOLSIG+  results for argon gas. It is shown that the anisotropic part of the electron-electron collision term, neglected in previous work, can in certain cases have a large effect on the electron mobility and is essential when describing the transition towards the Coulomb-collision dominated regime characterized by Spitzer transport coefficients. Finally, a brief overview is presented of the discharge conditions for which different Coulomb collision effects occur in different gases.

  13. Investigation of Coulomb dipole polarization effects on reactions involving exotic nuclei

    NASA Astrophysics Data System (ADS)

    Fernández-García, J. P.; Alvarez, M. A. G.; Chamon, L. C.

    2015-07-01

    We have analyzed elastic scattering angular distributions and total reaction cross sections of the exotic nuclei 11,9Li on 208Pb, at energies below and above the Coulomb barrier. For this purpose, we have used an optical potential with no adjustable parameters, composed by the nuclear São Paulo potential, derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization potential, derived from the semiclassical theory of Coulomb excitation. Within this formalism, we identified an unusual long-range absorption for the +208Pb 11Li system, which is dominated by the Coulomb interaction. We compare it to the absorption mechanisms observed for +208Pb6He which, unlike those of +208Pb11Li, take place at small interacting distances, where both Coulomb and nuclear interactions are important. The proposed approach shows to be a fundamental basis to study reactions involving exotic nuclei.

  14. Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials

    NASA Astrophysics Data System (ADS)

    Roy Chowdhury, Dibakar; Xu, Ningning; Zhang, Weili; Singh, Ranjan

    2015-07-01

    Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials.

  15. A combined first principles and Mohr-Coulomb criterion for the determination of the nanohardness of amorphous silicon

    NASA Astrophysics Data System (ADS)

    Tabatabaei, Maryam; Shodja, Hossein M.

    2015-12-01

    Although, the evaluation of the nanohardness of amorphous silicon (a-Si) has been the subject of a few experimental works but, to date, it has not been addressed theoretically yet. In this work, first principles Kohn-Sham density functional theory (DFT)-based molecular dynamics (MD) in combination with Mohr-Coulomb criterion is employed to calculate the ideal shear strength of the damped MD annealed a-Si sample containing dangling and floating bonds which are pertinent to the threefold- and fivefold-coordinated defects, respectively, as well as distorted tetrahedral bonds. The stress state beneath the nanoindenter is triaxial, and is accounted for properly. The calculated values of nanohardness are in reasonable agreement with those values measured experimentally. Consideration of the electronic charge distribution under the state of triaxial tension test reveals that the yield phenomenon in a-Si is accompanied by the transformation of a threefold-coordinated Si atom to a fourfold-coordinated.

  16. Photodetachment of Zwitterions: Probing Intramolecular Coulomb Repulsion and Attraction in the Gas Phase Using Pyridinium Dicarboxylate Anions

    SciTech Connect

    Wang, Xue B.; Dacres, J E.; Yang, Xin; Broadus , K M.; Lis, Lev; Wang, Lai S.; Kass, Steven R.

    2003-10-23

    Zwitterions are critically important in many biological transformations and are used in numerous chemical processes. The consequences of electrostatic effects on reactivity and physical properties, however, are largely unknown. In this work, we report the results of negative ion photoelectron spectra of nine isomeric pyridinium dicarboxylate zwitterions and three nonzwitterionic methoxycarbonylpyridine carboxylate isomers (-O(2)CPyrCO(2)CH(3)). Information about the intramolecular electrostatic interactions was directly obtained from the photoelectron spectra. The adiabatic and vertical detachment energies were measured and understood in terms of intramolecular Coulombic forces. Calculations at the B3LYP and CCSD(T) level were performed and compared to the experimental electron binding energies. Structures, relative stabilities, and the electron detachment sites also were obtained from the calculations.

  17. Floral Transformation of Wheat

    NASA Astrophysics Data System (ADS)

    Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

    A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

  18. Medical data transformation using rewriting

    PubMed Central

    Ashish, Naveen; Toga, Arthur W.

    2015-01-01

    This paper presents a system for declaratively transforming medical subjects' data into a common data model representation. Our work is part of the “GAAIN” project on Alzheimer's disease data federation across multiple data providers. We present a general purpose data transformation system that we have developed by leveraging the existing state-of-the-art in data integration and query rewriting. In this work we have further extended the current technology with new formalisms that facilitate expressing a broader range of data transformation tasks, plus new execution methodologies to ensure efficient data transformation for disease datasets. PMID:25750622

  19. Comparison of different transformation methods for Aspergillus giganteus.

    PubMed

    Meyer, Vera; Mueller, Dirk; Strowig, Till; Stahl, Ulf

    2003-08-01

    Four different transformation methods were tested and compared in an attempt to facilitate the genetic transformation of Aspergillus giganteus, the producer of an antifungal protein (AFP). The fungus was transformed to hygromycin B resistance, using the hph gene of Escherichia coli by protoplast transformation, electroporation, biolistic transformation, and Agrobacterium tumefaciens-mediated transformation. Electroporation and biolistic transformation were found to be inappropriate for transforming A. giganteus, due to a low transformation yield. The conventional transformation technique based on protoplasts yielded up to 55 transformants in 10(8) protoplasts/microg DNA and was enhanced to 140-fold by A. tumefaciens-mediated transfer of its T-DNA. Here, the germination time prior to cocultivation and the fungus:bacterium ratio were found to alter the transformation efficiency. Southern blot analysis revealed that the A. giganteus transformants contained a randomly integrated single T-DNA copy, whereas multiple integration events were frequent in transformants obtained by the protoplast method. PMID:12756496

  20. Coulomb drag between one-dimensional electron systems

    NASA Astrophysics Data System (ADS)

    Muhammad, Mustafa

    We have measured Coulomb drag (CD) between two spatially separated and electrically isolated one-dimensional (1D) wires to study the Luttinger liquid (LL) state in 1D systems. We have fabricated dual-wire CD devices with long quantum wires (≥ 1 microm) and short quantum wires (≤ 500 nm) with respect to the thermal lengths. The devices are made from high-mobility (≅10 6cm2/Vs) two-dimensional electron gas (2DEG) in AlGaAs/GaAs heterostructures, using high-resolution e-beam lithography, combined with metal deposition by e-beam evaporation to form surface Schottky gates. Peak in drag voltage occurs when the subband bottoms of the lowest energy subbands of the drive and the drag wires line up with each other and the Fermi level. We have observed drag on 1 microm device at 22 mK temperature which is found to be reminiscent of the drag observed earlier on a 2 microm device. An extensive reanalysis of the drag results obtained on the 2 microm device indicates a power-law temperature dependence of drag for both identical and non-identical wires. Also drag is found to decay exponentially with the mismatch between the wires. These properties indicate the existence of Luttinger liquid (LL) state in the long wire device. We have observed positive and negative drags on short wire devices. The observed temperature dependence of drag resistance, for both positive and negative drags, shows first an increase, followed by a constant plateau and finally a decrease as the temperature is increased. This is in line with the predictions of the Fermi--Luttinger liquid (FLL) forward momentum transfer theory. This is the first experimental observation of 1D Coulomb drag due to forward momentum transfer between wires. A negative drag between same type of carriers (holes or electrons) may conceivably result from forward momentum transfer or forward scattering if the band curvature of the drag wire at or near the Fermi point is negative. Negative band curvature may result from asymmetry

  1. Coulomb drag between one-dimensional electron systems

    NASA Astrophysics Data System (ADS)

    Muhammad, Mustafa

    We have measured Coulomb drag (CD) between two spatially separated and electrically isolated one-dimensional (1D) wires to study the Luttinger liquid (LL) state in 1D systems. We have fabricated dual-wire CD devices with long quantum wires (≥ 1 mum) and short quantum wires (≤ 500 nm) with respect to the thermal lengths. The devices are made from high-mobility (≅106cm2/Vs) two-dimensional electron gas (2DEG) in AlGaAs/GaAs heterostructures, using high-resolution e-beam lithography, combined with metal deposition by e-beam evaporation to form surface Schottky gates. Peak in drag voltage occurs when the subband bottoms of the lowest energy subbands of the drive and the drag wires line up with each other and the Fermi level. We have observed drag on 1 mum device at 22 mK temperature which is found to be reminiscent of the drag observed earlier on a 2 mum device. An extensive reanalysis of the drag results obtained on the 2 mum device indicates a power-law temperature dependence of drag for both identical and non-identical wires. Also drag is found to decay exponentially with the mismatch between the wires. These properties indicate the existence of Luttinger liquid (LL) state in the long wire device. We have observed positive and negative drags on short wire devices. The observed temperature dependence of drag resistance, for both positive and negative drags, shows first an increase, followed by a constant plateau and finally a decrease as the temperature is increased. This is in line with the predictions of the Fermi-Luttinger liquid (FLL) forward momentum transfer theory. This is the first experimental observation of 1D Coulomb drag due to forward momentum transfer between wires. A negative drag between same type of carriers (holes or electrons) may conceivably result from forward momentum transfer or forward scattering if the band curvature of the drag wire at or near the Fermi point is negative. Negative band curvature may result from asymmetry in the wire

  2. Electronic ground state properties of Coulomb blockaded quantum dots

    NASA Astrophysics Data System (ADS)

    Patel, Satyadev Rajesh

    Conductance through quantum dots at low temperature exhibits random but repeatable fluctuations arising from quantum interference of electrons. The observed fluctuations follow universal statistics arising from the underlying universality of quantum chaos. Random matrix theory (RMT) has provided an accurate description of the observed universal conductance fluctuations (UCF) in "open" quantum dots (device conductance ≥e 2/h). The focus of this thesis is to search for and decipher the underlying origin of similar universal properties in "closed" quantum dots (device conductance ≤e2/ h). A series of experiments is presented on electronic ground state properties measured via conductance measurements in Coulomb blockaded quantum dots. The statistics of Coulomb blockade (CB) peak heights with zero and non-zero magnetic field measured in various devices agree qualitatively with predictions from Random Matrix Theory (RMT). The standard deviation of the peak height fluctuations for non-zero magnetic field is lower than predicted by RMT; the temperature dependence of the standard deviation of the peak height for non-zero magnetic field is also measured. The second experiment summarizes the statistics of CB peak spacings. The peak spacing distribution width is observed to be on the order of the single particle level spacing, Delta, for both zero and non-zero magnetic field. The ratio of the zero field peak spacing distribution width to the non-zero field peak spacing distribution width is ˜1.2; this is good agreement with predictions from spin-resolved RMT predictions. The standard deviation of the non-zero magnetic field peak spacing distribution width shows a T-1/2 dependence in agreement with a thermal averaging model. The final experiment summarizes the measurement of the peak height correlation length versus temperature for various quantum dots. The peak height correlation length versus temperature saturates in small quantum dots, suggesting spectral scrambling

  3. Interatomic and intermolecular Coulombic decay: the coming of age story

    NASA Astrophysics Data System (ADS)

    Jahnke, T.

    2015-04-01

    In pioneering work by Cederbaum et al an excitation mechanism was proposed that occurs only in loosely bound matter (Cederbaum et al 1997 Phys. Rev. Lett. 79 4778): it turned out, that (in particular) in cases where a local Auger decay is energetically forbidden, an excited atom or molecule is able to decay in a scheme which was termed ‘interatomic Coulombic decay’ (or ‘intermolecular Coulombic decay’) (ICD). As ICD occurs, the excitation energy is released by transferring it to an atomic or molecular neighbor of the initially excited particle. As a consequence the neighboring atom or molecule is ionized as it receives the energy. A few years later the existence of ICD was confirmed experimentally (Marburger et al 2003 Phys. Rev. Lett. 90 203401; Jahnke et al 2004 Phys. Rev. Lett. 93 163401; Öhrwall et al 2004 Phys. Rev. Lett. 93 173401) by different techniques. Since this time it has been found that ICD is not (as initially suspected) an exotic feature of van der Waals or hydrogen bonded systems, but that ICD is a very general and common feature occurring after a manifold of excitation schemes and in numerous weakly bound systems, as revealed by more than 200 publications. It was even demonstrated, that ICD can become more efficient than a local Auger decay in some system. This review will concentrate on recent experimental investigations on ICD. It will briefly introduce the phenomenon and give a short summary of the ‘early years’ of ICD (a detailed view on this episode of investigations can be found in the review article by U Hergenhahn with the same title (Hergenhahn 2011 J. Electron Spectrosc. Relat. Phenom. 184 78)). More recent articles will be presented that investigate the relevance of ICD in biological systems and possible radiation damage of such systems due to ICD. The occurrence of ICD and ICD-like processes after different excitation schemes and in different systems is covered in the middle section: in that context the helium dimer (He2

  4. Precise Coulomb Wave Functions for a Wide Range of Complex l, η, and z

    SciTech Connect

    Michel, Nicolas L

    2007-01-01

    A new algorithm to calculate Coulomb wave functions with all of its arguments complex is proposed. For that purpose, standard methods such as continued fractions and power/asymptotic series are combined with direct integrations of the Schroedinger equation in order to provide very stable calculations, even for large values of |{eta}| or |{lm}({ell})|. Moreover, a simple analytic continuation for R(z)<0 is introduced, so that this zone of the complex z-plane does not pose any problem. This code is particularly well suited for low-energy calculations and the calculation of resonances with extremely small widths. Numerical instabilities appear, however, when both |{eta}| and |{lm}({ell})| are large and |R({ell})| comparable or smaller than |{lm}({ell})|. Catalogue number:ADYO{_}v1{_}0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYO{_}v1{_}0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: none Computers on which the program has been tested: DELL GX400 Operating systems: Linux, Windows Programming language used: C++ No. of bits in a word: 64 No. of processors used: 1 Has the code been vectorized?: no No. of bytes in distributed program, including test data, etc.: 33 092 No. of lines in distributed program, including test data, etc.: 3210 Distribution format:tar.gz Nature of physical problem: The calculation of Coulomb wave functions with all of their arguments complex is revisited.

  5. SHARP transformation

    NASA Astrophysics Data System (ADS)

    Wyatt, Stephan

    2004-08-01

    The U.S. Navy"s SHAred Reconnaissance Pod (SHARP) employs the Recon/Optical, Inc. (ROI) CA-279 dual spectral band (visible/IR) digital cameras operating from an F-18E/F aircraft to perform low-to-high altitude reconnaissance missions. SHARP has proven itself combat worthy, with a rapid transition from development to operational deployment culminating in a highly reliable and effective reconnaissance capability for joint forces operating in Operation Iraqi Freedom (OIF). The U.S. Navy"s intelligence, surveillance and reconnaissance (ISR) roadmap transforms the SHARP system from being solely an independent reconnaissance sensor to a node in the growing Joint ISR network. ROI and the U.S. Navy have combined their resources to ensure the system"s transformation continues to follow the ISR road map. Pre-planned product improvements (P3I) for the CA-270 camera systems will lead the way in that transformation.

  6. Infrared analysis of propagators and vertices of Yang-Mills theory in Landau and Coulomb gauge

    SciTech Connect

    Schleifenbaum, W.; Leder, M.; Reinhardt, H.

    2006-06-15

    The infrared behavior of gluon and ghost propagators, ghost-gluon vertex, and three-gluon vertex is investigated for both the covariant Landau and the noncovariant Coulomb gauge. Assuming infrared ghost dominance, we find a unique infrared exponent in the d=4 Landau gauge, while in the d=3+1 Coulomb gauge we find two different infrared exponents. We also show that a finite dressing of the ghost-gluon vertex has no influence on the infrared exponents. Finally, we determine the infrared behavior of the three-gluon vertex analytically and calculate it numerically at the symmetric point in the Coulomb gauge.

  7. Coulomb corrections to the parameters of the Landau-Pomeranchuk-Migdal effect theory

    NASA Astrophysics Data System (ADS)

    Voskresenskaya, O.; Kuraev, E.; Torosyan, H.

    2014-07-01

    Using the Coulomb correction to the screening angular parameter of the Molière multiple scattering theory we obtained analytically and numerically the Coulomb corrections to the quantities of the Migdal LPM effect theory. We showed that the Coulomb correction to the spectral bremsstrahlung rate allows one to eliminate the discrepancy between the predictions of the LPM effect theory and its measurement at least for high- Z targets and also to improve additionally the agreement between the predictions of the LPM effect theory analogue for a thin layer of matter and experimental data.

  8. Slow Noncollinear Coulomb Scattering in the Vicinity of the Dirac Point in Graphene.

    PubMed

    König-Otto, J C; Mittendorff, M; Winzer, T; Kadi, F; Malic, E; Knorr, A; Berger, C; de Heer, W A; Pashkin, A; Schneider, H; Helm, M; Winnerl, S

    2016-08-19

    The Coulomb scattering dynamics in graphene in energetic proximity to the Dirac point is investigated by polarization resolved pump-probe spectroscopy and microscopic theory. Collinear Coulomb scattering rapidly thermalizes the carrier distribution in k directions pointing radially away from the Dirac point. Our study reveals, however, that, in almost intrinsic graphene, full thermalization in all directions relying on noncollinear scattering is much slower. For low photon energies, carrier-optical-phonon processes are strongly suppressed and Coulomb mediated noncollinear scattering is remarkably slow, namely on a ps time scale. This effect is very promising for infrared and THz devices based on hot carrier effects. PMID:27588881

  9. Slow Noncollinear Coulomb Scattering in the Vicinity of the Dirac Point in Graphene

    NASA Astrophysics Data System (ADS)

    König-Otto, J. C.; Mittendorff, M.; Winzer, T.; Kadi, F.; Malic, E.; Knorr, A.; Berger, C.; de Heer, W. A.; Pashkin, A.; Schneider, H.; Helm, M.; Winnerl, S.

    2016-08-01

    The Coulomb scattering dynamics in graphene in energetic proximity to the Dirac point is investigated by polarization resolved pump-probe spectroscopy and microscopic theory. Collinear Coulomb scattering rapidly thermalizes the carrier distribution in k directions pointing radially away from the Dirac point. Our study reveals, however, that, in almost intrinsic graphene, full thermalization in all directions relying on noncollinear scattering is much slower. For low photon energies, carrier-optical-phonon processes are strongly suppressed and Coulomb mediated noncollinear scattering is remarkably slow, namely on a ps time scale. This effect is very promising for infrared and THz devices based on hot carrier effects.

  10. Optical spectra and intensities of graphene magnetic dot bound to a negatively charged Coulomb impurity

    SciTech Connect

    Lee, C. M. E-mail: apkschan@cityu.edu.hk; Chan, K. S. E-mail: apkschan@cityu.edu.hk

    2014-07-28

    Employing numerical diagonalization, we study the optical properties of an electron in a monolayer-graphene magnetic dot bound to an off-center negatively charged Coulomb impurity based on the massless Dirac-Weyl model. Numerical results show that, since the electron-hole symmetry is broken by the Coulomb potential, the optical absorption spectra of the magnetic dot in the presence of a Coulomb impurity are different between the electron states and the hole states. Effects of both the magnetic field and the dot size on the absorption coefficient are presented as functions of the incident photon energies.

  11. Integrated automation for continuous high-throughput synthetic chromosome assembly and transformation to identify improved yeast strains for industrial production of peptide sweetener brazzein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production and recycling of recombinant sweetener peptides in industrial biorefineries involves the evaluation of large numbers of genes and proteins. High-throughput integrated robotic molecular biology platforms that have the capacity to rapidly synthesize, clone, and express heterologous gene ope...

  12. Dark Coulomb binding of heavy neutrinos of fourth family

    NASA Astrophysics Data System (ADS)

    Belotsky, K. M.; Esipova, E. A.; Khlopov, M. Yu.; Laletin, M. N.

    2015-11-01

    Direct dark matter searches put severe constraints on the weakly interacting massive particles (WIMPs). These constraints cause serious troubles for the model of stable neutrino of fourth generation with mass around 50GeV. Though the calculations of primordial abundance of these particles make them in the charge symmetric case a sparse subdominant component of the modern dark matter, their presence in the universe would exceed the current upper limits by several orders of the magnitude. However, if quarks and leptons of fourth generation possess their own Coulomb-like y-interaction, recombination of pairs of heavy neutrinos and antineutrinos and their annihilation in the “neutrinium” atoms can play important role in their cosmological evolution, reducing their modern abundance far below the experimental upper limits. The model of stable fourth generation assumes that the dominant part of dark matter is explained by excessive Ū antiquarks, forming (ŪŪŪ)-- charged clusters, bound with primordial helium in nuclear-interacting O-helium (OHe) dark atoms. The y charge conservation implies generation of the same excess of fourth generation neutrinos, potentially dangerous WIMP component of this scenario. We show that due to y-interaction recombination of fourth neutrinos with OHe hides these WIMPs from direct WIMP searches, leaving the negligible fraction of free neutrinos, what makes their existence compatible with the experimental constraints.

  13. The mystery of Coulomb friction in sediment transport

    NASA Astrophysics Data System (ADS)

    Pähtz, Thomas; Duran, Orencio

    Nearly all analytical models of sediment transport in Newtonian fluid (e.g., air or water) are based on Bagnold's assumption of a constant Coulomb friction coefficient (particle-shear-pressure-ratio, μ) at the interface (zb) between sediment bed and transport layer. In fact, this assumption is the main reason why these models predict the sediment load (and subsequently the sediment transport rate) to be proportional to the excess shear stress (τ -τt), a scaling which has been confirmed in many wind-tunnel and flume experiments. Attempts to explain why μ (zb) is constant have usually been based on the sliding-friction analogy or rheology arguments. However, here we analytically derive μ (zs) √{ 3} - 1 , where zs is the location at which the production rate of particle fluctuation energy is maximal. Our derivation is based on the assumption that the rate of collisional transfer of horizontal into vertical kinetic energy is typically much larger than the rate of energy dissipation. Using state-of-the-art numerical simulations of sediment transport in Newtonian fluid, we validate all assumptions and approximation involved in our derivation. Interestingly, the location zs can significantly deviate from zb depending on the simulated conditions. We acknowledge support from grants National Natural Science Foundation of China (Nos. 1151101041 and 41376095) and Natural Science Foundation of Zhejiang Province (No. LR16E090001).

  14. Enhanced current noise correlations in a Coulomb-Majorana device

    NASA Astrophysics Data System (ADS)

    Lü, Hai-Feng; Lu, Hai-Zhou; Shen, Shun-Qing

    2016-06-01

    Majorana bound states (MBSs) nested in a topological nanowire are predicted to manifest nonlocal correlations in the presence of a finite energy splitting between the MBSs. However, the signal of the nonlocal correlations has not yet been detected in experiments. A possible reason is that the energy splitting is too weak and seriously affected by many system parameters. Here we investigate the charging energy induced nonlocal correlations in a hybrid device of MBSs and quantum dots. The nanowire that hosts the MBSs is assumed in proximity to a mesoscopic superconducting island with a finite charging energy. Each end of the nanowire is coupled to one lead via a quantum dot with resonant levels. With a floating superconducting island, the devices show a negative differential conductance and giant super-Poissonian shot noise, due to the interplay between the nonlocality of the MBSs and dynamical Coulomb blockade effect. When the island is strongly coupled to a bulk superconductor, the current cross correlations at small lead chemical potentials are negative by tuning the dot energy levels. In contrast, the cross correlation is always positive in a non-Majorana setup. This difference may provide a signature for the existence of the MBSs.

  15. Coulomb blockade phenomena in ultrathin Langmuir-Blodgett sandwich junctions

    NASA Astrophysics Data System (ADS)

    Burghard, M.; Mueller-Schwanneke, C.; Philipp, G.; Roth, S.

    1999-04-01

    Electrical junctions were fabricated in sandwich configuration from Langmuir-Blodgett (LB) films of two types of material, 0953-8984/11/14/015/img1-conjugated, peripherally substituted ring systems or a 0953-8984/11/14/015/img2-bonded polymer. The sandwich junctions consisted of four to ten monolayers between two micro-structured gold electrodes, corresponding to a nominal film thickness between about 8 and 20 nm. At liquid helium temperature, the current (I)/voltage (V) characteristics generally exhibited smooth exponential behaviour or irregular steps. However, for a small fraction of the LB sandwiches comprising a 0953-8984/11/14/015/img1-conjugated or 0953-8984/11/14/015/img2-bonded compound, regular staircases were observed. It was possible to fit such 0953-8984/11/14/015/img5 characteristics with curves calculated on the basis of a Coulomb blockade model. These results are accounted for by the presence of nanometre-sized gold particles formed upon evaporation of the top electrode. Single electron tunnelling is assumed to proceed through double tunnel barrier junctions consisting of a gold island asymmetrically located between the top and bottom electrode.

  16. Le probleme quantique bicomplexe du potentiel de Coulomb

    NASA Astrophysics Data System (ADS)

    Mathieu, Jeremie

    In this master's thesis, is gathered a great part of my work on bicomplex quantum mechanics. Bicomplex numbers are the second order multicomplex generalization of complex numbers. Equipped with the standard addition and multiplication, they form an algebraic structure called a commutative ring with unity and are one of many known generalizations of the real number system. It has been almost eighty years since it's been proposed to use an algebra of a superior dimension than the one of complex numbers to construct the mathematical formalism of quantum mechanics. However it's only been since less than a decade ago that the idea of using the bicomplex numbers to do so has been seriously considered. In that sense, the complete resolution of the quantum harmonic oscillator in a bicomplex Hilbert space was the first major achievement of this ambitious project. This thesis, by article style, is a continuation of this work of generalization. It presents, by an axiomatic approach, the complete differential solution of the bicomplex quantum Coulomb potential problem and half of its algebraic solution.

  17. Short-range Coulomb correlations render massive Dirac fermions massless

    NASA Astrophysics Data System (ADS)

    Ebrahimkhas, M.; Jafari, S. A.

    2012-04-01

    Tight-binding electrons on a honeycomb lattice are described by an effective Dirac theory at low energies. Lowering symmetry by an alternate ionic potential (Δ) generates a single-particle gap in the spectrum. We employ the dynamical mean-field theory (DMFT) technique to study the effect of on-site electron correlation (U) on massive Dirac fermions. For a fixed mass parameter Δ, we find that beyond a critical value Uc1(Δ) massive Dirac fermions become massless. Further increasing U beyond Uc2(Δ), there will be another phase transition to the Mott insulating state. Therefore, the competition between the single-particle gap parameter, Δ, and the Hubbard U restores the semi-metallic nature of the parent Hamiltonian. The width of the intermediate semi-metallic regime shrinks by increasing the ionic potential. However, at small values of Δ, there is a wide interval of U values for which the system remains semi-metal. The implication of this result for graphene is that in contrast to a single-particle picture, the on-site Coulomb repulsion makes the Dirac cone spectrum robust against small values of the symmetry breaking parameter Δ.

  18. Entanglement generation using discrete solitons in Coulomb crystals.

    PubMed

    Landa, H; Retzker, A; Schaetz, T; Reznik, B

    2014-08-01

    Laser-cooled and trapped ions can crystallize and feature discrete solitons that are nonlinear, topologically protected configurations of the Coulomb crystal. Such solitons, as their continuum counterparts, can move within the crystal, while their discreteness leads to the existence of a gap-separated, spatially localized motional mode of oscillation above the spectrum. Suggesting that these unique properties of discrete solitons can be used for generating entanglement between different sites of the crystal, we study a detailed proposal in the context of state-of-the-art experimental techniques. We analyze the interaction of periodically driven planar ion crystals with optical forces, revealing the effects of micromotion in radio-frequency traps inherent to such structures, as opposed to linear ion chains. The proposed method requires Doppler cooling of the crystal and sideband cooling of the soliton's localized modes alone. Since the gap separation of the latter is nearly independent of the crystal size, this approach could be particularly useful for producing entanglement and studying system-environment interactions in large, two- and possibly three-dimensional systems. PMID:25126914

  19. Symmetry and boundness of four-particle coulomb systems

    SciTech Connect

    Rebane, T. K.

    2012-04-15

    The problem of boundness of a{sup +}b{sup +}c{sup -}d{sup -} four-particle Coulomb systems (quadrions) is studied versus the masses of the particles involved. Inequalities that make it possible to deduce that, if some reference quadrions form a bound state, the same is true for a large number of quadrions formed by particles having various masses were derived. A compendium of calculations for energies of reference systems that possess various symmetries [positronium molecules (e{sup +}e{sup +}e{sup -}e{sup -}) and quadrions of the a{sup +}b{sup +}b{sup -}b{sup -}, a{sup +}b{sup +}a{sup --}, and a{sup +}a{sup +}b{sup -}c{sup -} types] is given, and groups of bound asymmetric quadrions corresponding to them are determined. An inequality for kinetic energies of particles that makes it possible to find out, by using asymmetric reference systems, whether specific quadrions are bound is obtained. It is shown that the boundness of many quadrions is ensured by the boundness of respective three-particle systems. The entire body of the present results permits proving that, of the total number of 406 quadrions containing electrons, muons, pions, kaons, protons, deuterons, and tritons and their antiparticles, 227 quadrions are bound.

  20. Coulomb drag and tunneling studies in quantum Hall bilayers

    NASA Astrophysics Data System (ADS)

    Nandi, Debaleena

    The bilayer quantum Hall state at total filling factor νT=1, where the total electron density matches the degeneracy of the lowest Landau level, is a prominent example of Bose-Einstein condensation of excitons. A macroscopically ordered state is realized where an electron in one layer is tightly bound to a "hole" in the other layer. If exciton transport were the only bulk transportmechanism, a current driven in one layer would spontaneously generate a current of equal magnitude and opposite sign in the other layer. The Corbino Coulomb drag measurements presented in this thesis demonstrate precisely this phenomenon. Excitonic superfluidity has been long sought in the νT=1 state. The tunneling between the two electron gas layers exihibit a dc Josephson-like effect. A simple model of an over-damped voltage biased Josephson junction is in reasonable agreement with the observed tunneling I -- V. At small tunneling biases, it exhibits a tunneling "supercurrent". The dissipation is carefully studied in this tunneling "supercurrent" and found to remain small but finite.