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Sample records for one-dimensional perturbation code

  1. A transport based one-dimensional perturbation code for reactivity calculations in metal systems

    SciTech Connect

    Wenz, T.R.

    1995-02-01

    A one-dimensional reactivity calculation code is developed using first order perturbation theory. The reactivity equation is based on the multi-group transport equation using the discrete ordinates method for angular dependence. In addition to the first order perturbation approximations, the reactivity code uses only the isotropic scattering data, but cross section libraries with higher order scattering data can still be used with this code. The reactivity code obtains all the flux, cross section, and geometry data from the standard interface files created by ONEDANT, a discrete ordinates transport code. Comparisons between calculated and experimental reactivities were done with the central reactivity worth data for Lady Godiva, a bare uranium metal assembly. Good agreement is found for isotopes that do not violate the assumptions in the first order approximation. In general for cases where there are large discrepancies, the discretized cross section data is not accurately representing certain resonance regions that coincide with dominant flux groups in the Godiva assembly. Comparing reactivities calculated with first order perturbation theory and a straight {Delta}k/k calculation shows agreement within 10% indicating the perturbation of the calculated fluxes is small enough for first order perturbation theory to be applicable in the modeled system. Computation time comparisons between reactivities calculated with first order perturbation theory and straight {Delta}k/k calculations indicate considerable time can be saved performing a calculation with a perturbation code particularly as the complexity of the modeled problems increase.

  2. A Computer Code System for the Calculation of Reactivity and Kinetic Parameters by One-Dimensional Neutron Transport Perturbation Theory.

    1985-02-01

    Version 00 TP1 is a transport theory code, developed to determine reactivity effects and kinetic parameters such as effective delayed neutron fractions and mean generation time by applying the usual perturbation formalism for one-dimensional geometry.

  3. Sandia One-Dimensional Direct and Inverse Thermal Code

    1995-02-27

    SODDIT is a reliable tool for solving a wide variety of one-dimensional transient heat conduction problems. Originally developed in 1972 to predict the ablation of graphite/carbon bodies reentering the earth''s atmosphere, it has since been modified by the authors to extend its capabilities well beyond its original scope.

  4. Fast large scale structure perturbation theory using one-dimensional fast Fourier transforms

    NASA Astrophysics Data System (ADS)

    Schmittfull, Marcel; Vlah, Zvonimir; McDonald, Patrick

    2016-05-01

    The usual fluid equations describing the large-scale evolution of mass density in the universe can be written as local in the density, velocity divergence, and velocity potential fields. As a result, the perturbative expansion in small density fluctuations, usually written in terms of convolutions in Fourier space, can be written as a series of products of these fields evaluated at the same location in configuration space. Based on this, we establish a new method to numerically evaluate the 1-loop power spectrum (i.e., Fourier transform of the 2-point correlation function) with one-dimensional fast Fourier transforms. This is exact and a few orders of magnitude faster than previously used numerical approaches. Numerical results of the new method are in excellent agreement with the standard quadrature integration method. This fast model evaluation can in principle be extended to higher loop order where existing codes become painfully slow. Our approach follows by writing higher order corrections to the 2-point correlation function as, e.g., the correlation between two second-order fields or the correlation between a linear and a third-order field. These are then decomposed into products of correlations of linear fields and derivatives of linear fields. The method can also be viewed as evaluating three-dimensional Fourier space convolutions using products in configuration space, which may also be useful in other contexts where similar integrals appear.

  5. Fourier Representation Methods for Møller-Plesset Perturbation Theory in One-Dimensionally Periodic Systems

    NASA Astrophysics Data System (ADS)

    Fripiat, J. G.; Delhalle, J.; Harris, Frank E.

    2007-12-01

    Ab initio studies of one-dimensionally periodic systems are advantageously carried out by methods that employ Fourier representations and the Ewald method for accelerating the lattice sums. This communication desribes the first investigation in which these techniques have been applied at the Mo/ller-Plesset level of perturbation theory, MBPT(2). Second-order corrections to the restricted Hartree-Fock energy and energy bands are reported for H2, Be, and LiH chains, and these results are compared to direct-space extended-system and oligomer computations. The methods described herein exhibit improved convergence relative to the other methods to which they are compared.

  6. GASPS: A time-dependent, one-dimensional, planar gas dynamics computer code

    SciTech Connect

    Pierce, R.E.; Sutton, S.B.; Comfort, W.J. III

    1986-12-05

    GASP is a transient, one-dimensional planar gas dynamic computer code that can be used to calculate the propagation of a shock wave. GASP, developed at LLNL, solves the one-dimensional planar equations governing momentum, mass and energy conservation. The equations are cast in an Eulerian formulation where the mesh is fixed in space, and material flows through it. Thus it is necessary to account for convection of material from one cell to its neighbor.

  7. Proof of a Conjecture for the One-Dimensional Perturbed Gelfand Problem from Combustion Theory

    NASA Astrophysics Data System (ADS)

    Huang, Shao-Yuan; Wang, Shin-Hwa

    2016-11-01

    We study global bifurcation curves and the exact multiplicity of positive solutions for the two-point boundary value problem arising in combustion theory: u^' ' }(x)+λ exp (au/a+u) =0,quad -1 0} is the Frank-Kamenetskii parameter and a > 0 is the activation energy parameter. We prove that there exists a critical bifurcation value a 0 {≈ 4.069} such that, on the {(λ,||u||_{∞})}-plane, the bifurcation curve is S-shaped for {a > a0} and is monotone increasing for {0 < a ≤q a0}. That is, we prove the long-standing conjecture for the one-dimensional perturbed Gelfand problem. We also study, in the {(a,λ, Vert uVert _{∞})}-space, the shape and structure of the bifurcation surface.

  8. Proof of a Conjecture for the One-Dimensional Perturbed Gelfand Problem from Combustion Theory

    NASA Astrophysics Data System (ADS)

    Huang, Shao-Yuan; Wang, Shin-Hwa

    2016-05-01

    We study global bifurcation curves and the exact multiplicity of positive solutions for the two-point boundary value problem arising in combustion theory: u^' ' (x)+λ exp (au/a+u) =0,quad -1 0} is the Frank-Kamenetskii parameter and a > 0 is the activation energy parameter. We prove that there exists a critical bifurcation value a 0 {≈ 4.069} such that, on the {(λ,||u||_{∞})} -plane, the bifurcation curve is S-shaped for {a > a0} and is monotone increasing for {0 < a ≤q a0} . That is, we prove the long-standing conjecture for the one-dimensional perturbed Gelfand problem. We also study, in the {(a,λ, Vert uVert _{∞})} -space, the shape and structure of the bifurcation surface.

  9. TOPAZ - the transient one-dimensional pipe flow analyzer: code validation and sample problems

    SciTech Connect

    Winters, W.S.

    1985-10-01

    TOPAZ is a ''user friendly'' computer code for modeling the one-dimensional-transient physics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. This document presents a series of sample problems designed to aid potential users in creating TOPAZ input files. To the extent possible, sample problems were selected for which analytical solutions currently exist. TOPAZ comparisons with such solutions are intended to provide a measure of code validation.

  10. A generalized one-dimensional computer code for turbomachinery cooling passage flow calculations

    NASA Technical Reports Server (NTRS)

    Kumar, Ganesh N.; Roelke, Richard J.; Meitner, Peter L.

    1989-01-01

    A generalized one-dimensional computer code for analyzing the flow and heat transfer in the turbomachinery cooling passages was developed. This code is capable of handling rotating cooling passages with turbulators, 180 degree turns, pin fins, finned passages, by-pass flows, tip cap impingement flows, and flow branching. The code is an extension of a one-dimensional code developed by P. Meitner. In the subject code, correlations for both heat transfer coefficient and pressure loss computations were developed to model each of the above mentioned type of coolant passages. The code has the capability of independently computing the friction factor and heat transfer coefficient on each side of a rectangular passage. Either the mass flow at the inlet to the channel or the exit plane pressure can be specified. For a specified inlet total temperature, inlet total pressure, and exit static pressure, the code computers the flow rates through the main branch and the subbranches, flow through tip cap for impingement cooling, in addition to computing the coolant pressure, temperature, and heat transfer coefficient distribution in each coolant flow branch. Predictions from the subject code for both nonrotating and rotating passages agree well with experimental data. The code was used to analyze the cooling passage of a research cooled radial rotor.

  11. MULTI-IFE-A one-dimensional computer code for Inertial Fusion Energy (IFE) target simulations

    NASA Astrophysics Data System (ADS)

    Ramis, R.; Meyer-ter-Vehn, J.

    2016-06-01

    The code MULTI-IFE is a numerical tool devoted to the study of Inertial Fusion Energy (IFE) microcapsules. It includes the relevant physics for the implosion and thermonuclear ignition and burning: hydrodynamics of two component plasmas (ions and electrons), three-dimensional laser light ray-tracing, thermal diffusion, multigroup radiation transport, deuterium-tritium burning, and alpha particle diffusion. The corresponding differential equations are discretized in spherical one-dimensional Lagrangian coordinates. Two typical application examples, a high gain laser driven capsule and a low gain radiation driven marginally igniting capsule are discussed. In addition to phenomena relevant for IFE, the code includes also components (planar and cylindrical geometries, transport coefficients at low temperature, explicit treatment of Maxwell's equations) that extend its range of applicability to laser-matter interaction at moderate intensities (<1016 W cm-2). The source code design has been kept simple and structured with the aim to encourage user's modifications for specialized purposes.

  12. Benchmarking report for WIGGLE: A one-dimensional transient diffusion theory code

    SciTech Connect

    Pevey, R.E.

    1990-11-01

    WIGGLE is a static/transient one-dimensional diffusion theory calculation written to estimate the axial power profile while safety rods are falling during a scram. The code is used in the LOCA Limits Analysis Package (LLAP), a part of the SRS system for calculating thermal-hydraulic limits. Since WIGGLE was designed to be implemented through LLAP and not as a stand-alone code, it consists entirely of subroutines; the problem data must be passed to it from a driver routine. This project concerned the verification of WIGGLE, which limited it to the determination that WIGGLE is correctly implementing the transient 1D diffusion equation. The approach was to compare the results of the code with three analytic solutions: a static homogeneous calculation of the pre-accident power profile (without end-fittings); a static heterogeneous calculation of the pre-accident power profile (includes end-fittings); and a transient calculation designed to test the time-dependent calculational ability. The results of all three calculations were essentially identical to the analytical solutions, thus giving us confidence that WIGGLE is correctly solving the one-dimensional time-dependent diffusion equation.

  13. TOPP: A post-processor for TOPAZ, the one dimensional pipe flow analysis code

    SciTech Connect

    Martin, R.W.

    1987-07-01

    TOPP is a Lawrence Livermore National Laboratory (LLNL) post-processor for producing graphical results from the one dimensional pipe flow analysis code, TOPAZ. TOPAZ was written by W. S. Winters of Sandia National Laboratory, Livermore (SNLL) and is available on the CRAY computers at LLNL. The SNLL version of TOPAZ produces a very limited set of variables that can be used as input to a post-processor. The version at LLNL has been modified to output every time-dependent variable to an absolute binary file at the user specified minor edit frequency. TOPP reads this absolute binary file and produces a variety of graphical results. 2 refs.

  14. One-dimensional transport code modeling of the divertor-limiter region in tokamaks

    SciTech Connect

    Ogden, J.M.; Singer, C.E.; Post, D.E.; Jensen, R.V.; Seidl, F.G.P.

    1981-12-01

    A model of the diverter-limiter scrapeoff region has been incorporated into the BALDUR one-dimensional tokamak transport code. Simulations of the proposed Toroidal Fusion Test Reactor (TFTR), and Poloidal Diverter (PDX) experiments and existing Alcator-A tokamak experiments have been carried out for ohmic and neutral beam heated cases. In particular it is studied how the edge conditions and energy-loss mechanisms in PDX depend upon plasma density, and results are compared with analytic estimates. The sensitivity of the results to changes in the transport coefficients and scrapeoff model is discussed with particular reference to the power loading on the TFTR limiter. 13 refs.

  15. One-dimensional transport code modelling of the limiter-divertor region in tokamaks

    SciTech Connect

    Ogden, J.M.; Post, D.E.; Jensen, R.V.; Seidl, F.G.P.

    1980-02-01

    A model of the limiter-divertor scrape-off region has been incorporated into the BALDUR one-dimensional tokamak transport code. Simulations of PDX and ALCATOR have been carried out for ohmic and neutral beam heated cases. In particular, we have studied how the edge conditions and energy loss mechanisms of PDX depend upon plasma density, and compared our results with analytic estimates. The sensitivity of the results to changes in the transport coefficients and scrape-off model is also discussed.

  16. 1DB, a one-dimensional diffusion code for nuclear reactor analysis

    SciTech Connect

    Little, W.W. Jr. )

    1991-09-01

    1DB is a multipurpose, one-dimensional (plane, cylinder, sphere) diffusion theory code for use in reactor analysis. The code is designed to do the following: To compute k{sub eff} and perform criticality searches on time absorption, reactor composition, reactor dimensions, and buckling by means of either a flux or an adjoint model; to compute collapsed microscopic and macroscopic cross sections averaged over the spectrum in any specified zone; to compute resonance-shielded cross sections using data in the shielding factor format; and to compute isotopic burnup using decay chains specified by the user. All programming is in FORTRAN. Because variable dimensioning is employed, no simple restrictions on problem complexity can be stated. The number of spatial mesh points, energy groups, upscattering terms, etc. is limited only by the available memory. The source file contains about 3000 cards. 4 refs.

  17. Robustness of one-dimensional viscous fluid motion under multidimensional perturbations

    NASA Astrophysics Data System (ADS)

    Feireisl, Eduard; Sun, Yongzhong

    2015-12-01

    We adapt the relative energy functional associated to the compressible Navier-Stokes system to show stability of solutions emanating from 1-D initial data with respect to multidimensional N = 2, 3 perturbations. Besides the application of the relative energy inequality as a suitable "distance" between two solutions, refined regularity estimates in Lp based Sobolev spaces are used.

  18. Thermodynamic perturbation theory for associating fluids confined in a one-dimensional pore

    SciTech Connect

    Marshall, Bennett D.

    2015-06-21

    In this paper, a new theory is developed for the self-assembly of associating molecules confined to a single spatial dimension, but allowed to explore all orientation angles. The interplay of the anisotropy of the pair potential and the low dimensional space results in orientationally ordered associated clusters. This local order enhances association due to a decrease in orientational entropy. Unlike bulk 3D fluids which are orientationally homogeneous, association in 1D necessitates the self-consistent calculation of the orientational distribution function. To test the new theory, Monte Carlo simulations are performed and the theory is found to be accurate. It is also shown that the traditional treatment in first order perturbation theory fails to accurately describe this system. The theory developed in this paper may be used as a tool to study hydrogen bonding of molecules in 1D zeolites as well as the hydrogen bonding of molecules in carbon nanotubes.

  19. Code System Calculate One-Dimensional Vertical Transport Unsaturated Soil Zone

    1989-03-01

    SESOIL, as an integrated screening-level soil compartment model, is designed to simultaneously model water transport, sediment transport, and pollutant fate. SESOIL is a one-dimensional vertical transport model for the unsaturated soil zone. Only one compound at a time can be considered. The model is based on mass balance and equilibrium partitioning of the chemical between different phases (dissolved, sorbed, vapor, and pure). The SESOIL model was designed to perform long-term simulations of chemical transport andmore » transformations in the soil and uses theoretically derived equations to represent water transport, sediment transport on the land surface, pollutant transformation, and migration of the pollutant to the atmosphere and groundwater. Climatic data, compartment geometry, and soil and chemical property data are the major components used in the equations. SESOIL was developed as a screening-level model, utilizing less soil, chemical, and meteorological values as input than most other similar models. Output of SESOIL includes time-varying pollutant concentrations at various soil depths and pollutant loss from the unsaturated zone in terms of surface runoff, percolation to the groundwater, volatilization, and degradation. The February 1995 release corrects an error that caused the code to fail when average monthly air temperature was -10C and includes an improved iteration procedure for the mass balance equations in the model. PLEASE NOTE: The RISKPRO information management software (see OTHER PROG/OPER SYS INFO) was used by the developers of the New SESOIL User''s Guide in their study and revisions of SESOIL. Using RISKPRO in conjunction with SESOIL is an option, and it may provide the easiest way to use SESOIL. The other option, use of SESOIL in stand-alone mode, has been tested and used. The stand-alone option is covered in ''Instructions for Running Stand-Alone SESOIL Code'', and in ''A Seasonal Soil Compartment Model''.« less

  20. One-dimensional single-mode nonlinear FEL amplification code: User's manual

    NASA Astrophysics Data System (ADS)

    Kishimoto, Yasuaki; Oda, Hisako

    1989-05-01

    The 1-dimensional single mode nonlinear FEL amplification code is developed which is useful for the basic design of Free Electron Laser. The wiggler field is given by the helical configuration, and the guide magnetic field for the stable beam propagation and the incident beam energy spread are taken into account. The tapered-wiggler with arbitrary configuration is also considered. The nonlinear FEL characteristics in the wide range from Compton to Raman regimes are analyzed since the electrostatic interaction between particles is included. The FEL code developed here is vectorized about 97%. Therefore, the large amount of parameter study for the optimization of machine design is possible.

  1. User's manual for the one-dimensional hypersonic experimental aero-thermodynamic (1DHEAT) data reduction code

    NASA Technical Reports Server (NTRS)

    Hollis, Brian R.

    1995-01-01

    A FORTRAN computer code for the reduction and analysis of experimental heat transfer data has been developed. This code can be utilized to determine heat transfer rates from surface temperature measurements made using either thin-film resistance gages or coaxial surface thermocouples. Both an analytical and a numerical finite-volume heat transfer model are implemented in this code. The analytical solution is based on a one-dimensional, semi-infinite wall thickness model with the approximation of constant substrate thermal properties, which is empirically corrected for the effects of variable thermal properties. The finite-volume solution is based on a one-dimensional, implicit discretization. The finite-volume model directly incorporates the effects of variable substrate thermal properties and does not require the semi-finite wall thickness approximation used in the analytical model. This model also includes the option of a multiple-layer substrate. Fast, accurate results can be obtained using either method. This code has been used to reduce several sets of aerodynamic heating data, of which samples are included in this report.

  2. Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

    SciTech Connect

    Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G.

    2012-07-01

    Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

  3. Application of a one-dimensional TEC code to the characterization of a lanthanum-hexaboride diode

    NASA Astrophysics Data System (ADS)

    van Dam, Scott A.; Ramalingam, Mysore L.

    A one-dimensional thermionic energy conversion (TEC) computer code has been utilized to provide a theoretical basis of comparison for experimentally derived data obtained from a lanthanum hexaboride cesium vapor thermionic diode. Although the code-generated predictions obtained were not in precise agreement with the experimental results, they do provide a basis for establishing the validity of the experimental results from an analytical framework. Certain discrepancies are thus identified, and an attempt is made to account for them in terms of code inaccuracies and/or possible experimental error. Experimental lanthanum-hexaboride (LaB6) cesium-vapor TEC diode characteristics are compared to those predicted by the TEC code. The diode used was activated by electron-bombardment heating in a rejuvenated diode testing facility. A DOS loop and auxiliary Fortran program were used in conjunction with the original TEC code to generate both general and LaB6 simulated diode current density vs. output voltage characteristics. The effects of changing the emitter and collector work functions and the operating cesium-vapor pressure were studied for both cases.

  4. One-Dimensional Lagrangian Code for Plasma Hydrodynamic Analysis of a Fusion Pellet Driven by Ion Beams.

    1986-12-01

    Version 00 The MEDUSA-IB code performs implosion and thermonuclear burn calculations of an ion beam driven ICF target, based on one-dimensional plasma hydrodynamics and transport theory. It can calculate the following values in spherical geometry through the progress of implosion and fuel burnup of a multi-layered target. (1) Hydrodynamic velocities, density, ion, electron and radiation temperature, radiation energy density, Rs and burn rate of target as a function of coordinates and time, (2) Fusion gainmore » as a function of time, (3) Ionization degree, (4) Temperature dependent ion beam energy deposition, (5) Radiation, -particle and neutron spectra as a function of time.« less

  5. TOPAZ: The transient one-dimensional pipe flow analyzer: An update on code improvements and increased capabilities

    SciTech Connect

    Winters, W.S.

    1987-09-01

    TOPAZ is a ''user-friendly'' computer code for modeling the one-dimensional, transient physics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. This report, the fourth in a series of reports documenting TOPAZ, discusses coding improvements and the addition of new capabilities. These improvements make the current version of TOPAZ considerably more versatile than the original version which was distributed last year. For example, the new version does not restrict the user to modeling only hydrogen and helium isotope flows. Users now have the capability of modeling arbitrary gas mixture flows. In addition users may define time-dependent functions for mass generation, energy deposition, flow area, and maximum integration time step. Parallel flow paths and flows through channels having noncircular cross-sections may now be simulated. Improvements in TOPAZ mesh generation have been made which permit users to add additional ''plumbing'' to existing models without renumbering the mesh. 7 refs., 3 figs., 8 tabs.

  6. Numerical Zooming Between a NPSS Engine System Simulation and a One-Dimensional High Compressor Analysis Code

    NASA Technical Reports Server (NTRS)

    Follen, Gregory; auBuchon, M.

    2000-01-01

    Within NASA's High Performance Computing and Communication (HPCC) program, NASA Glenn Research Center is developing an environment for the analysis/design of aircraft engines called the Numerical Propulsion System Simulation (NPSS). NPSS focuses on the integration of multiple disciplines such as aerodynamics, structures, and heat transfer along with the concept of numerical zooming between zero-dimensional to one-, two-, and three-dimensional component engine codes. In addition, the NPSS is refining the computing and communication technologies necessary to capture complex physical processes in a timely and cost-effective manner. The vision for NPSS is to create a "numerical test cell" enabling full engine simulations overnight on cost-effective computing platforms. Of the different technology areas that contribute to the development of the NPSS Environment, the subject of this paper is a discussion on numerical zooming between a NPSS engine simulation and higher fidelity representations of the engine components (fan, compressor, burner, turbines, etc.). What follows is a description of successfully zooming one-dimensional (row-by-row) high-pressure compressor analysis results back to a zero-dimensional NPSS engine simulation and a discussion of the results illustrated using an advanced data visualization tool. This type of high fidelity system-level analysis, made possible by the zooming capability of the NPSS, will greatly improve the capability of the engine system simulation and increase the level of virtual test conducted prior to committing the design to hardware.

  7. User's manual for ONEDANT: a code package for one-dimensional, diffusion-accelerated, neutral-particle transport

    SciTech Connect

    O'Dell, R.D.; Brinkley, F.W. Jr.; Marr, D.R.

    1982-02-01

    ONEDANT is designed for the CDC-7600, but the program has been implemented and run on the IBM-370/190 and CRAY-I computers. ONEDANT solves the one-dimensional multigroup transport equation in plane, cylindrical, spherical, and two-angle plane geometries. Both regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue search) problems subject to vacuum, reflective, periodic, white, albedo, or inhomogeneous boundary flux conditions are solved. General anisotropic scattering is allowed and anisotropic inhomogeneous sources are permitted. ONEDANT numerically solves the one-dimensional, multigroup form of the neutral-particle, steady-state form of the Boltzmann transport equation. The discrete-ordinates approximation is used for treating the angular variation of the particle distribution and the diamond-difference scheme is used for phase space discretization. Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm. A standard inner (within-group) iteration, outer (energy-group-dependent source) iteration technique is used. Both inner and outer iterations are accelerated using the diffusion synthetic acceleration method. (WHK)

  8. LPIC++ a parallel one-dimensional relativistic electromagnetic Particle-In-Cell code for simulating laser-plasma-interaction

    NASA Astrophysics Data System (ADS)

    Pfund, R. E. W.; Lichters, R.; Meyer-ter-Vehn, J.

    1998-02-01

    We report on a recently developed electromagnetic relativistic 1D3V (one spatial, three velocity dimensions) Particle-In-Cell code for simulating laser-plasma interaction at normal and oblique incidence. The code is written in C++ and easy to extend. The data structure is characterized by the use of chained lists for the grid cells as well as particles belonging to one cell. The parallel version of the code is based on PVM. It splits the grid into several spatial domains each belonging to one processor. Since particles can cross boundaries of cells as well as domains, the processor loads will generally change in time. This is counteracted by adjusting the domain sizes dynamically, for which the use of chained lists has proven to be very convenient. Moreover, an option for restarting the simulation from intermediate stages of the time evolution has been implemented even in the parallel version. The code will be published and distributed freely.

  9. TWANG-PIC, a novel gyro-averaged one-dimensional particle-in-cell code for interpretation of gyrotron experiments

    SciTech Connect

    Braunmueller, F. Tran, T. M.; Alberti, S.; Genoud, J.; Hogge, J.-Ph.; Tran, M. Q.; Vuillemin, Q.

    2015-06-15

    A new gyrotron simulation code for simulating the beam-wave interaction using a monomode time-dependent self-consistent model is presented. The new code TWANG-PIC is derived from the trajectory-based code TWANG by describing the electron motion in a gyro-averaged one-dimensional Particle-In-Cell (PIC) approach. In comparison to common PIC-codes, it is distinguished by its computation speed, which makes its use in parameter scans and in experiment interpretation possible. A benchmark of the new code is presented as well as a comparative study between the two codes. This study shows that the inclusion of a time-dependence in the electron equations, as it is the case in the PIC-approach, is mandatory for simulating any kind of non-stationary oscillations in gyrotrons. Finally, the new code is compared with experimental results and some implications of the violated model assumptions in the TWANG code are disclosed for a gyrotron experiment in which non-stationary regimes have been observed and for a critical case that is of interest in high power gyrotron development.

  10. Robustness of topological quantum codes: Ising perturbation

    NASA Astrophysics Data System (ADS)

    Zarei, Mohammad Hossein

    2015-02-01

    We study the phase transition from two different topological phases to the ferromagnetic phase by focusing on points of the phase transition. To this end, we present a detailed mapping from such models to the Ising model in a transverse field. Such a mapping is derived by rewriting the initial Hamiltonian in a new basis so that the final model in such a basis has a well-known approximated phase transition point. Specifically, we consider the toric codes and the color codes on various lattices with Ising perturbation. Our results provide a useful table to compare the robustness of the topological codes and to explicitly show that the robustness of the topological codes depends on triangulation of their underlying lattices.

  11. Determination of neutron flux distribution by using ANISN, a one-dimensional discrete S sub n ordinates transport code with anisotropic scattering

    NASA Technical Reports Server (NTRS)

    Ghorai, S. K.

    1983-01-01

    The purpose of this project was to use a one-dimensional discrete coordinates transport code called ANISN in order to determine the energy-angle-spatial distribution of neutrons in a 6-feet cube rock box which houses a D-T neutron generator at its center. The project was two-fold. The first phase of the project involved adaptation of the ANISN code written for an IBM 360/75/91 computer to the UNIVAC system at JSC. The second phase of the project was to use the code with proper geometry, source function and rock material composition in order to determine the neutron flux distribution around the rock box when a 14.1 MeV neutron generator placed at its center is activated.

  12. One-Dimensional, Multigroup Cross Section and Design Sensitivity and Uncertainty Analysis Code System - Generalized Perturbation Theory.

    1981-02-02

    Version: 00 SENSIT computes the sensitivity and uncertainty of a calculated integral response (such as a dose rate) due to input cross sections and their uncertainties. Sensitivity profiles are computed for neutron and gamma-ray reaction cross sections (of standard multigroup cross-section sets) and for secondary energy distributions (SED's) of multigroup scattering matrices.

  13. One-dimensional turbulence

    SciTech Connect

    Kerstein, A.R.

    1996-12-31

    One-Dimensional Turbulence is a new turbulence modeling strategy involving an unsteady simulation implemented in one spatial dimension. In one dimension, fine scale viscous and molecular-diffusive processes can be resolved affordably in simulations at high turbulence intensity. The mechanistic distinction between advective and molecular processes is thereby preserved, in contrast to turbulence models presently employed. A stochastic process consisting of mapping {open_quote}events{close_quote} applied to a one-dimensional velocity profile represents turbulent advection. The local event rate for given eddy size is proportional to the velocity difference across the eddy. These properties cause an imposed shear to induce an eddy cascade analogous in many respects to the eddy cascade in turbulent flow. Many scaling and fluctuation properties of self-preserving flows, and of passive scalars introduced into these flows, are reproduced.

  14. One-Dimensional Oscillator in a Box

    ERIC Educational Resources Information Center

    Amore, Paolo; Fernandez, Francisco M.

    2010-01-01

    We discuss a quantum-mechanical model of two particles that interact by means of a harmonic potential and are confined to a one-dimensional box with impenetrable walls. We apply perturbation theory to the cases of different and equal masses and analyse the symmetry of the states in the latter case. We compare the approximate perturbation results…

  15. One-Dimensional Czedli-Type Islands

    ERIC Educational Resources Information Center

    Horvath, Eszter K.; Mader, Attila; Tepavcevic, Andreja

    2011-01-01

    The notion of an island has surfaced in recent algebra and coding theory research. Discrete versions provide interesting combinatorial problems. This paper presents the one-dimensional case with finitely many heights, a topic convenient for student research.

  16. One-Dimensionality and Whiteness

    ERIC Educational Resources Information Center

    Calderon, Dolores

    2006-01-01

    This article is a theoretical discussion that links Marcuse's concept of one-dimensional society and the Great Refusal with critical race theory in order to achieve a more robust interrogation of whiteness. The author argues that in the context of the United States, the one-dimensionality that Marcuse condemns in "One-Dimensional Man" is best…

  17. Finite-temperature second-order many-body perturbation and Hartree–Fock theories for one-dimensional solids: An application to Peierls and charge-density-wave transitions in conjugated polymers

    SciTech Connect

    He, Xiao; Ryu, Shinsei; Hirata, So

    2014-01-14

    Finite-temperature extensions of ab initio Gaussian-basis-set spin-restricted Hartree–Fock (HF) and second-order many-body perturbation (MP2) theories are implemented for infinitely extended, periodic, one-dimensional solids and applied to the Peierls and charge-density-wave (CDW) transitions in polyyne and all-trans polyacetylene. The HF theory predicts insulating CDW ground states for both systems in their equidistant structures at low temperatures. In the same structures, they turn metallic at high temperatures. Starting from the “dimerized” low-temperature equilibrium structures, the systems need even higher temperatures to undergo a Peierls transition, which is accompanied by geometric as well as electronic distortions from dimerized to non-dimerized forms. The conventional finite-temperature MP2 theory shows a sign of divergence in any phase at any nonzero temperature and is useless. The renormalized finite-temperature MP2 (MP2R) theory is divergent only near metallic electronic structures, but is well behaved elsewhere. MP2R also predicts CDW and Peierls transitions occurring at two different temperatures. The effect of electron correlation is primarily to lower the Peierls transition temperature.

  18. Finite-temperature second-order many-body perturbation and Hartree-Fock theories for one-dimensional solids: an application to Peierls and charge-density-wave transitions in conjugated polymers.

    PubMed

    He, Xiao; Ryu, Shinsei; Hirata, So

    2014-01-14

    Finite-temperature extensions of ab initio Gaussian-basis-set spin-restricted Hartree-Fock (HF) and second-order many-body perturbation (MP2) theories are implemented for infinitely extended, periodic, one-dimensional solids and applied to the Peierls and charge-density-wave (CDW) transitions in polyyne and all-trans polyacetylene. The HF theory predicts insulating CDW ground states for both systems in their equidistant structures at low temperatures. In the same structures, they turn metallic at high temperatures. Starting from the "dimerized" low-temperature equilibrium structures, the systems need even higher temperatures to undergo a Peierls transition, which is accompanied by geometric as well as electronic distortions from dimerized to non-dimerized forms. The conventional finite-temperature MP2 theory shows a sign of divergence in any phase at any nonzero temperature and is useless. The renormalized finite-temperature MP2 (MP2R) theory is divergent only near metallic electronic structures, but is well behaved elsewhere. MP2R also predicts CDW and Peierls transitions occurring at two different temperatures. The effect of electron correlation is primarily to lower the Peierls transition temperature.

  19. Finite-temperature coupled-cluster, many-body perturbation, and restricted and unrestricted Hartree–Fock study on one-dimensional solids: Luttinger liquids, Peierls transitions, and spin- and charge-density waves

    SciTech Connect

    Hermes, Matthew R.; Hirata, So

    2015-09-14

    One-dimensional (1D) solids exhibit a number of striking electronic structures including charge-density wave (CDW) and spin-density wave (SDW). Also, the Peierls theorem states that at zero temperature, a 1D system predicted by simple band theory to be a metal will spontaneously dimerize and open a finite fundamental bandgap, while at higher temperatures, it will assume the equidistant geometry with zero bandgap (a Peierls transition). We computationally study these unique electronic structures and transition in polyyne and all-trans polyacetylene using finite-temperature generalizations of ab initio spin-unrestricted Hartree–Fock (UHF) and spin-restricted coupled-cluster doubles (CCD) theories, extending upon previous work [He et al., J. Chem. Phys. 140, 024702 (2014)] that is based on spin-restricted Hartree–Fock (RHF) and second-order many-body perturbation (MP2) theories. Unlike RHF, UHF can predict SDW as well as CDW and metallic states, and unlike MP2, CCD does not diverge even if the underlying RHF reference wave function is metallic. UHF predicts a gapped SDW state with no dimerization at low temperatures, which gradually becomes metallic as the temperature is raised. CCD, meanwhile, confirms that electron correlation lowers the Peierls transition temperature. Furthermore, we show that the results from all theories for both polymers are subject to a unified interpretation in terms of the UHF solutions to the Hubbard–Peierls model using different values of the electron-electron interaction strength, U/t, in its Hamiltonian. The CCD wave function is shown to encompass the form of the exact solution of the Tomonaga–Luttinger model and is thus expected to describe accurately the electronic structure of Luttinger liquids.

  20. Finite-temperature coupled-cluster, many-body perturbation, and restricted and unrestricted Hartree-Fock study on one-dimensional solids: Luttinger liquids, Peierls transitions, and spin- and charge-density waves.

    PubMed

    Hermes, Matthew R; Hirata, So

    2015-09-14

    One-dimensional (1D) solids exhibit a number of striking electronic structures including charge-density wave (CDW) and spin-density wave (SDW). Also, the Peierls theorem states that at zero temperature, a 1D system predicted by simple band theory to be a metal will spontaneously dimerize and open a finite fundamental bandgap, while at higher temperatures, it will assume the equidistant geometry with zero bandgap (a Peierls transition). We computationally study these unique electronic structures and transition in polyyne and all-trans polyacetylene using finite-temperature generalizations of ab initio spin-unrestricted Hartree-Fock (UHF) and spin-restricted coupled-cluster doubles (CCD) theories, extending upon previous work [He et al., J. Chem. Phys. 140, 024702 (2014)] that is based on spin-restricted Hartree-Fock (RHF) and second-order many-body perturbation (MP2) theories. Unlike RHF, UHF can predict SDW as well as CDW and metallic states, and unlike MP2, CCD does not diverge even if the underlying RHF reference wave function is metallic. UHF predicts a gapped SDW state with no dimerization at low temperatures, which gradually becomes metallic as the temperature is raised. CCD, meanwhile, confirms that electron correlation lowers the Peierls transition temperature. Furthermore, we show that the results from all theories for both polymers are subject to a unified interpretation in terms of the UHF solutions to the Hubbard-Peierls model using different values of the electron-electron interaction strength, U/t, in its Hamiltonian. The CCD wave function is shown to encompass the form of the exact solution of the Tomonaga-Luttinger model and is thus expected to describe accurately the electronic structure of Luttinger liquids. PMID:26374011

  1. Development of depletion perturbation theory for a reactor nodal code

    SciTech Connect

    Bowman, S.M.

    1981-09-01

    A generalized depletion perturbation (DPT) theory formulation for light water reactor (LWR) depletion problems is developed and implemented into the three-dimensional LWR nodal code SIMULATE. This development applies the principles of the original derivation by M.L. Williams to the nodal equations solved by SIMULATE. The present formulation is first described in detail, and the nodal coupling methodology in SIMULATE is used to determine partial derivatives of the coupling coefficients. The modifications to the original code and the new DPT options available to the user are discussed. Finally, the accuracy and the applicability of the new DPT capability to LWR design analysis are examined for several LWR depletion test cases. The cases range from simple static cases to a realistic PWR model for an entire fuel cycle. Responses of interest included K/sub eff/, nodal peaking, and peak nodal exposure. The nonlinear behavior of responses with respect to perturbations of the various types of cross sections was also investigated. The time-dependence of the sensitivity coefficients for different responses was examined and compared. Comparison of DPT results for these examples to direct calculations reveals the limited applicability of depletion perturbation theory to LWR design calculations at the present. The reasons for these restrictions are discussed, and several methods which might improve the computational accuracy of DPT are proposed for future research.

  2. Development of Generalized Perturbation Theory Capability within the SCALE Code Package

    SciTech Connect

    Jessee, Matthew Anderson; Williams, Mark L; DeHart, Mark D

    2009-01-01

    Computational capability has been developed to calculate sensitivity coefficients of generalized responses with respect to cross-section data in the SCALE code system. The focus of this paper is the implementation of generalized perturbation theory (GPT) for one-dimensional and two-dimensional deterministic neutron transport calculations. GPT is briefly summarized for computing sensitivity coefficients for reaction rate ratio responses within the existing framework of the TSUNAMI sensitivity and uncertainty (S/U) analysis code package in SCALE. GPT provides the capability to analyze generalized responses related to reactor analysis, such as homogenized cross-sections, relative powers, and conversion ratios, as well as measured experimental parameters such as 28 (epithermal/thermal 238U capture rates) in thermal benchmarks and fission ratios such as 239Pu(n,f)/235U(n,f) in fast benchmarks. The S/U analysis of these experimental integral responses can be used to augment the existing TSUNAMI S/U analysis capabilities for system similarity assessment and data adjustment. S/U analysis is provided for boiling water reactor pin cell as part of the Organization for Economic Cooperation and Development Uncertainty Analysis in Modeling benchmark.

  3. Transient One-dimensional Pipe Flow Analyzer

    1986-04-08

    TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and variousmore » form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.« less

  4. Transient One-dimensional Pipe Flow Analyzer

    SciTech Connect

    1986-04-08

    TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and various form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.

  5. GATO Code Modification to Compute Plasma Response to External Perturbations

    NASA Astrophysics Data System (ADS)

    Turnbull, A. D.; Chu, M. S.; Ng, E.; Li, X. S.; James, A.

    2006-10-01

    It has become increasingly clear that the plasma response to an external nonaxiymmetric magnetic perturbation cannot be neglected in many situations of interest. This response can be described as a linear combination of the eigenmodes of the ideal MHD operator. The eigenmodes of the system can be obtained numerically with the GATO ideal MHD stability code, which has been modified for this purpose. A key requirement is the removal of inadmissible continuum modes. For Finite Hybrid Element codes such as GATO, a prerequisite for this is their numerical restabilization by addition of small numerical terms to δ,to cancel the analytic numerical destabilization. In addition, robustness of the code was improved and the solution method speeded up by use of the SuperLU package to facilitate calculation of the full set of eigenmodes in a reasonable time. To treat resonant plasma responses, the finite element basis has been extended to include eigenfunctions with finite jumps at rational surfaces. Some preliminary numerical results for DIII-D equilibria will be given.

  6. One-Dimensional Heat Conduction

    SciTech Connect

    Sutton, Steven B.

    1992-03-09

    ICARUS-LLNL was developed to solve one-dimensional planar, cylindrical, or spherical conduction heat transfer problems. The IBM PC version is a family of programs including ICARUSB, an interactive BASIC heat conduction program; ICARUSF, a FORTRAN heat conduction program; PREICAR, a BASIC preprocessor for ICARUSF; and PLOTIC and CPLOTIC, interpretive BASIC and compiler BASIC plot postprocessor programs. Both ICARUSB and ICARUSF account for multiple material regions and complex boundary conditions, such as convection or radiation. In addition, ICARUSF accounts for temperature-dependent material properties and time or temperature-dependent boundary conditions. PREICAR is a user-friendly preprocessor used to generate or modify ICARUSF input data. PLOTIC and CPLOTIC generate plots of the temperature or heat flux profile at specified times, plots of the variation of temperature or heat flux with time at selected nodes, or plots of the solution grid. First developed in 1974 to allow easy modeling of complex one-dimensional systems, its original application was in the nuclear explosive testing program. Since then it has undergone extensive revision and been applied to problems dealing with laser fusion target fabrication, heat loads on underground tests, magnetic fusion switching tube anodes, and nuclear waste isolation canisters.

  7. One-Dimensional Heat Conduction

    1992-03-09

    ICARUS-LLNL was developed to solve one-dimensional planar, cylindrical, or spherical conduction heat transfer problems. The IBM PC version is a family of programs including ICARUSB, an interactive BASIC heat conduction program; ICARUSF, a FORTRAN heat conduction program; PREICAR, a BASIC preprocessor for ICARUSF; and PLOTIC and CPLOTIC, interpretive BASIC and compiler BASIC plot postprocessor programs. Both ICARUSB and ICARUSF account for multiple material regions and complex boundary conditions, such as convection or radiation. In addition,more » ICARUSF accounts for temperature-dependent material properties and time or temperature-dependent boundary conditions. PREICAR is a user-friendly preprocessor used to generate or modify ICARUSF input data. PLOTIC and CPLOTIC generate plots of the temperature or heat flux profile at specified times, plots of the variation of temperature or heat flux with time at selected nodes, or plots of the solution grid. First developed in 1974 to allow easy modeling of complex one-dimensional systems, its original application was in the nuclear explosive testing program. Since then it has undergone extensive revision and been applied to problems dealing with laser fusion target fabrication, heat loads on underground tests, magnetic fusion switching tube anodes, and nuclear waste isolation canisters.« less

  8. One-dimensional Cooper pairing

    NASA Astrophysics Data System (ADS)

    Mendoza, R.; Fortes, M.; de Llano, M.; Solís, M. A.

    2011-09-01

    We study electron pairing in a one-dimensional (1D) fermion gas at zero temperature under zero- and finite-range, attractive, two-body interactions. The binding energy of Cooper pairs (CPs) with zero total or center-of-mass momentum (CMM) increases with attraction strength and decreases with interaction range for fixed strength. The excitation energy of 1D CPs with nonzero CMM display novel, unique properties. It satisfies a dispersion relation with two branches: a phonon-like linear excitation for small CP CMM; this is followed by roton-like quadratic excitation minimum for CMM greater than twice the Fermi wavenumber, but only above a minimum threshold attraction strength. The expected quadratic-in-CMM dispersion in vacuo when the Fermi wavenumber is set to zero is recovered for any coupling. This paper completes a three-part exploration initiated in 2D and continued in 3D.

  9. Gene Perturbation Atlas (GPA): a single-gene perturbation repository for characterizing functional mechanisms of coding and non-coding genes.

    PubMed

    Xiao, Yun; Gong, Yonghui; Lv, Yanling; Lan, Yujia; Hu, Jing; Li, Feng; Xu, Jinyuan; Bai, Jing; Deng, Yulan; Liu, Ling; Zhang, Guanxiong; Yu, Fulong; Li, Xia

    2015-01-01

    Genome-wide transcriptome profiling after gene perturbation is a powerful means of elucidating gene functional mechanisms in diverse contexts. The comprehensive collection and analysis of the resulting transcriptome profiles would help to systematically characterize context-dependent gene functional mechanisms and conduct experiments in biomedical research. To this end, we collected and curated over 3000 transcriptome profiles in human and mouse from diverse gene perturbation experiments, which involved 1585 different perturbed genes (microRNAs, lncRNAs and protein-coding genes) across 1170 different cell lines/tissues. For each profile, we identified differential genes and their associated functions and pathways, constructed perturbation networks, predicted transcription regulation and cancer/drug associations, and assessed cooperative perturbed genes. Based on these transcriptome analyses, the Gene Perturbation Atlas (GPA) can be used to detect (i) novel or cell-specific functions and pathways affected by perturbed genes, (ii) protein interactions and regulatory cascades affected by perturbed genes, and (iii) perturbed gene-mediated cooperative effects. The GPA is a user-friendly database to support the rapid searching and exploration of gene perturbations. Particularly, we visualized functional effects of perturbed genes from multiple perspectives. In summary, the GPA is a valuable resource for characterizing gene functions and regulatory mechanisms after single-gene perturbations. The GPA is freely accessible at http://biocc.hrbmu.edu.cn/GPA/. PMID:26039571

  10. Gene Perturbation Atlas (GPA): a single-gene perturbation repository for characterizing functional mechanisms of coding and non-coding genes.

    PubMed

    Xiao, Yun; Gong, Yonghui; Lv, Yanling; Lan, Yujia; Hu, Jing; Li, Feng; Xu, Jinyuan; Bai, Jing; Deng, Yulan; Liu, Ling; Zhang, Guanxiong; Yu, Fulong; Li, Xia

    2015-06-03

    Genome-wide transcriptome profiling after gene perturbation is a powerful means of elucidating gene functional mechanisms in diverse contexts. The comprehensive collection and analysis of the resulting transcriptome profiles would help to systematically characterize context-dependent gene functional mechanisms and conduct experiments in biomedical research. To this end, we collected and curated over 3000 transcriptome profiles in human and mouse from diverse gene perturbation experiments, which involved 1585 different perturbed genes (microRNAs, lncRNAs and protein-coding genes) across 1170 different cell lines/tissues. For each profile, we identified differential genes and their associated functions and pathways, constructed perturbation networks, predicted transcription regulation and cancer/drug associations, and assessed cooperative perturbed genes. Based on these transcriptome analyses, the Gene Perturbation Atlas (GPA) can be used to detect (i) novel or cell-specific functions and pathways affected by perturbed genes, (ii) protein interactions and regulatory cascades affected by perturbed genes, and (iii) perturbed gene-mediated cooperative effects. The GPA is a user-friendly database to support the rapid searching and exploration of gene perturbations. Particularly, we visualized functional effects of perturbed genes from multiple perspectives. In summary, the GPA is a valuable resource for characterizing gene functions and regulatory mechanisms after single-gene perturbations. The GPA is freely accessible at http://biocc.hrbmu.edu.cn/GPA/.

  11. Reflectometry as a fluctuation diagnostic: A one-dimensional simulation

    SciTech Connect

    Chou, A.E.; Luhmann, N.C. Jr.; Peebles, W.A.; Rhodes, T.L. )

    1992-10-01

    Reflectometry is currently employed to characterize turbulence in fusion plasmas worldwide and is expected to be a major diagnostic on the next generation of machines (e.g., ITER). Until recently, little was known about the response of a reflectometer to fluctuations (degree of localization of the signal, sensitivity to fluctuation wave number, dependence on density scale length, etc.). To elucidate these properties, we have been modeling reflectometer behavior with a code based on solution of a one-dimensional full wave equation. The code models an infinite plane plasma with density gradient in the {ital x} direction and solves the full wave equation to find the electric field of the reflectometer's electromagnetic wave. It can simulate stationary and moving density perturbations with arbitrary waveforms and wave numbers in plasmas with arbitrary density profiles. We present results of test cases comparing computational results to known analytic solutions for linear and 1{minus}{alpha}{sup 2}/{ital x}{sup 2} plasma density profiles, which show very good agreement.

  12. A One Dimensional, Time Dependent Inlet/Engine Numerical Simulation for Aircraft Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Garrard, Doug; Davis, Milt, Jr.; Cole, Gary

    1999-01-01

    The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet/engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.

  13. PYESSENCE: Generalized Coupled Quintessence Linear Perturbation Python Code

    NASA Astrophysics Data System (ADS)

    Leithes, Alexander

    2016-09-01

    PYESSENCE evolves linearly perturbed coupled quintessence models with multiple (cold dark matter) CDM fluid species and multiple DE (dark energy) scalar fields, and can be used to generate quantities such as the growth factor of large scale structure for any coupled quintessence model with an arbitrary number of fields and fluids and arbitrary couplings.

  14. Interaction of one-dimensional waves in media without dispersion

    NASA Astrophysics Data System (ADS)

    Vasileva, O. A.; Karabutov, A. A.; Lapshin, E. A.; Rudenko, O. V.

    Numerical and analytical studies of the excitation and propagation of nondispersing waves of finite amplitude are examined; difference schemes for the calculation of generalized solutions are considered along with a third-order-accuracy scheme. Attention is given to one-dimensional regular and random perturbations: plane, cylindrical, and spherical convergent waves. A considerable amount of the material is given in the form of tables and figures, which makes it possible to use the work as a handbook.

  15. Stationary one-dimensional dispersive shock waves.

    PubMed

    Kartashov, Yaroslav V; Kamchatnov, Anatoly M

    2012-02-01

    We address shock waves generated upon the interaction of tilted plane waves with negative refractive index defects in defocusing media with linear gain and two-photon absorption. We found that, in contrast to conservative media where one-dimensional dispersive shock waves usually exist only as nonstationary objects expanding away from a defect or generating beam, the competition between gain and two-photon absorption in a dissipative medium results in the formation of localized stationary dispersive shock waves, whose transverse extent may considerably exceed that of the refractive index defect. One-dimensional dispersive shock waves are stable if the defect strength does not exceed a certain critical value.

  16. One-Dimensional Wavefront Sensor Analysis

    1996-04-25

    This software analyzes one-dimensional wavefront sensor data acquired with any of several data acquisition systems. It analyzes the data to determine centroids, wavefront slopes and overall wavefront error. The data can be displayed in many formats, with plots of various parameters vs time and position, including computer generated movies. Data can also be exported for use by other programs.

  17. One-dimensional parabolic-beam photonic crystal laser.

    PubMed

    Ahn, Byeong-Hyeon; Kang, Ju-Hyung; Kim, Myung-Ki; Song, Jung-Hwan; Min, Bumki; Kim, Ki-Soo; Lee, Yong-Hee

    2010-03-15

    We report one-dimensional (1-D) parabolic-beam photonic crystal (PhC) lasers in which the width of the PhC slab waveguide is parabolically tapered. A few high-Q resonant modes are confirmed in the vicinity of the tapered region where Gaussian-shaped photonic well is formed. These resonant modes originate from the dielectric PhC guided mode and overlap with the gain medium efficiently. It is also shown that the far-field radiation profile is closely associated with the symmetry of the structural perturbation.

  18. Spin transport in a one-dimensional anisotropic Heisenberg model.

    PubMed

    Znidarič, Marko

    2011-06-01

    We analytically and numerically study spin transport in a one-dimensional Heisenberg model in linear-response regime at infinite temperature. It is shown that as the anisotropy parameter Δ is varied spin transport changes from ballistic for Δ<1 to anomalous at the isotropic point Δ=1, to diffusive for finite Δ>1, ending up as a perfect isolator in the Ising limit of infinite Δ. Using perturbation theory for large Δ a quantitative prediction is made for the dependence of diffusion constant on Δ. PMID:21702588

  19. Programmers manual for a one-dimensional Lagrangian transport model

    USGS Publications Warehouse

    Schoellhamer, D.H.; Jobson, H.E.

    1986-01-01

    A one-dimensional Lagrangian transport model for simulating water-quality constituents such as temperature, dissolved oxygen , and suspended sediment in rivers is presented in this Programmers Manual. Lagrangian transport modeling techniques, the model 's subroutines, and the user-written decay-coefficient subroutine are discussed in detail. Appendices list the program codes. The Programmers Manual is intended for the model user who needs to modify code either to adapt the model to a particular need or to use reaction kinetics not provided with the model. (Author 's abstract)

  20. Computer model of one-dimensional equilibrium controlled sorption processes

    USGS Publications Warehouse

    Grove, D.B.; Stollenwerk, K.G.

    1984-01-01

    A numerical solution to the one-dimensional solute-transport equation with equilibrium-controlled sorption and a first-order irreversible-rate reaction is presented. The computer code is written in FORTRAN language, with a variety of options for input and output for user ease. Sorption reactions include Langmuir, Freundlich, and ion-exchange, with or without equal valance. General equations describing transport and reaction processes are solved by finite-difference methods, with nonlinearities accounted for by iteration. Complete documentation of the code, with examples, is included. (USGS)

  1. One-dimensional nano-interconnection formation.

    PubMed

    Ji, Jianlong; Zhou, Zhaoying; Yang, Xing; Zhang, Wendong; Sang, Shengbo; Li, Pengwei

    2013-09-23

    Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized.

  2. Loschmidt echo in one-dimensional interacting Bose gases

    SciTech Connect

    Lelas, K.; Seva, T.; Buljan, H.

    2011-12-15

    We explore Loschmidt echo in two regimes of one-dimensional interacting Bose gases: the strongly interacting Tonks-Girardeau (TG) regime, and the weakly interacting mean-field regime. We find that the Loschmidt echo of a TG gas decays as a Gaussian when small (random and time independent) perturbations are added to the Hamiltonian. The exponent is proportional to the number of particles and the magnitude of a small perturbation squared. In the mean-field regime the Loschmidt echo shows richer behavior: it decays faster for larger nonlinearity, and the decay becomes more abrupt as the nonlinearity increases; it can be very sensitive to the particular realization of the noise potential, especially for relatively small nonlinearities.

  3. Superconducting cosmic strings and one dimensional extended supersymmetric algebras

    SciTech Connect

    Oikonomou, V.K.

    2014-11-15

    In this article we study in detail the supersymmetric structures that underlie the system of fermionic zero modes around a superconducting cosmic string. Particularly, we extend the analysis existing in the literature on the one dimensional N=2 supersymmetry and we find multiple N=2, d=1 supersymmetries. In addition, compact perturbations of the Witten index of the system are performed and we find to which physical situations these perturbations correspond. More importantly, we demonstrate that there exists a much more rich supersymmetric structure underlying the system of fermions with N{sub f} flavors and these are N-extended supersymmetric structures with non-trivial topological charges, with “N” depending on the fermion flavors.

  4. One-dimensional hypersonic phononic crystals.

    PubMed

    Gomopoulos, N; Maschke, D; Koh, C Y; Thomas, E L; Tremel, W; Butt, H-J; Fytas, G

    2010-03-10

    We report experimental observation of a normal incidence phononic band gap in one-dimensional periodic (SiO(2)/poly(methyl methacrylate)) multilayer film at gigahertz frequencies using Brillouin spectroscopy. The band gap to midgap ratio of 0.30 occurs for elastic wave propagation along the periodicity direction, whereas for inplane propagation the system displays an effective medium behavior. The phononic properties are well captured by numerical simulations. The porosity in the silica layers presents a structural scaffold for the introduction of secondary active media for potential coupling between phonons and other excitations, such as photons and electrons.

  5. Enhancing one dimensional sensitivity with plasmonic coupling.

    PubMed

    O'Mullane, Samuel; Peterson, Brennan; Race, Joseph; Keller, Nick; Diebold, Alain C

    2014-10-20

    In this paper, we propose a cross-grating structure to enhance the critical dimension sensitivity of one dimensional nanometer scale metal gratings. Making use of the interaction between slight changes in refractive index and localized plasmons, we demonstrate sub-angstrom scale sensitivity in this structure. Compared to unaltered infinite metal gratings and truncated finite gratings, this cross-grating structure shows robust spectra dependent mostly on the dimension of the smaller line width and pitch. While typical scatterometry simulations show angstrom resolution at best, this structure has demonstrated picometer resolution. Due to the wide range of acceptable specifications, we expect experimental confirmation of such structures to soon follow. PMID:25401657

  6. The one-dimensional hydrogen atom revisited

    NASA Astrophysics Data System (ADS)

    Palma, G.; Raff, U.

    2006-09-01

    The one-dimensional Schrodinger hydrogen atom is an interesting mathematical and physical problem for the study of bound states, eigenfunctions, and quantum-degeneracy issues. This one-dimensional physical system has given rise to some intriguing controversy for more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier-transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found that the complete Balmer energy spectrum is obtained together with an odd-parity set of eigenfunctions. Closed-form solutions in both coordinate and momentum spaces were obtained. No twofold degeneracy was observed as predicted by the degeneracy theorem in one dimension, though it does not necessarily have to hold for potentials with singularities. No ground state with infinite energy exists since the corresponding eigenfunction does not satisfy the Schrodinger equation at the origin.

  7. Accuracy of differential sensitivity for one-dimensional shock problems

    SciTech Connect

    Henninger, R.J.; Maudlin, P.J.; Rightley, M.L.

    1998-07-01

    The technique called Differential Sensitivity has been applied to the system of Eulerian continuum mechanics equations solved by a hydrocode. Differential Sensitivity uses forward and adjoint techniques to obtain output response sensitivity to input parameters. Previous papers have described application of the technique to two-dimensional, multi-component problems. Inaccuracies in the adjoint solutions have prompted us to examine our numerical techniques in more detail. Here we examine one-dimensional, one material shock problems. Solution accuracy is assessed by comparison to sensitivities obtained by automatic differentiation and a code-based adjoint differentiation technique. {copyright} {ital 1998 American Institute of Physics.}

  8. A new code to study structures in collisionally active, perturbed debris discs: application to binaries

    NASA Astrophysics Data System (ADS)

    Thébault, P.

    2012-01-01

    Context. Debris discs are traditionally studied using two distinct types of numerical models: statistical particle-in-a-box codes to study their collisional and size distribution evolution, and dynamical N-body models to study their spatial structure. The absence of collisions in N-body codes is in particular a major shortcoming, as collisional processes are expected to significantly alter the results obtained from pure N-body runs. Aims: We present a new numerical model, to study the spatial structure of perturbed debris discs in both a dynamical and collisional steady-state. We focus on the competing effects of gravitational perturbations by a massive body (planet or star), the collisional production of small grains, and the radiation pressure placing these grains in possibly dynamically unstable regions. Methods: We consider a disc of parent bodies in a dynamical steady-state, from which small radiation-pressure-affected grains are released in a series of runs, each corresponding to a different orbital position of the perturber, where particles are assigned a collisional destruction probability. These collisional runs produce successive position maps that are then recombined, following a complex procedure, to generate surface density profiles for each orbital position of the perturbing body. Results: We apply our code to the case of a circumprimary disc in a binary. We find pronounced structures inside and outside the dynamical stability regions. For low eB, the disc's structure is time varying, with spiral arms in the dynamically "forbidden" region precessing with the companion star. For high eB, the disc is strongly asymmetric but time invariant, with a pronounced density drop in the binary's periastron direction.

  9. Study of the early signal perturbations due to GJ and Elves using the LWPC code

    NASA Astrophysics Data System (ADS)

    Nait Amor, Samir; Ghalila, Hassen; Bouderba, Yasmina

    2015-04-01

    Early events are a Very Low Frequencies (VLF) signal perturbations recorded during a lightning activity. The properties of these signal perturbations and their association to the lightning peak current and/or Transient Luminous Events (TLEs) were widely studied. In a recently analysis a new early signal perturbations whose recovery time persists for several minutes were discovered. The underlying cause of these events is still unclear. In a recently published work, these events were attributed to the lightning peak current and the type of associated TLE. In others, and newly published papers, analyzes were done where all kind of early events were considered. Statistical results showed that the occurrence of long recovery events is independent of the lightning current amplitude and/or TLEs type. To understand which is the main cause of these events, we analyzed two types of early signal perturbations: One was a typical event (~200s time duration) in association with a Gigantic Jet and the second was a long recovery event in association with an elve recorded on December 12 2009 during the EuroSprite campaign. In addition to the VLF signal analysis, we used the Long Wave Propagation Capability (LWPC) code to simulate the unperturbed and perturbed signal parameters (amplitude and phase), to determine the signal modes attenuation coefficient and then to infer the electron density increases in the disturbed region. The results showed that the reference height was reduced from its ambient value (87km) to 66.4 km in the case of the GJ and 74.3 km for the elve. These reference heights decreases affected the propagating signal at the disturbed region by increasing the modes attenuation coefficient. Effectively, the number of modes was reduced from 28 at ambient condition to 9 modes (in the case of GJ) and 17 (in the case of elve). This high attenuation of modes leads to the appearance of null signal perturbations positions due to the interferences. Between two null positions

  10. Three one-dimensional structural heating programs

    NASA Technical Reports Server (NTRS)

    Wing, L. D.

    1978-01-01

    Two computer programs for calculating profiles in a ten-element structure consisting of up to ten materials are presented, along with a third program for calculating the mean temperature for a payload container placed in an orbiting vehicle cargo bay. The three programs are related by the sharing of a common analytical technique; the energy balance is based upon one-dimensional heat transfer. The first program, NQLDW112, assumes a non-ablating surface. NQLDW117 is very similar but allows the outermost element to ablate. NQLDW040 calculates an average temperature profile through an idealized model of the real payload cannister and contents in the cargo bay of an orbiting vehicle.

  11. Electron transport in one-dimensional plasmas

    SciTech Connect

    Wienke, B.R.

    1983-11-01

    A one-dimensional, multigroup, discrete ordinates technique for computing electron energy deposition in plasmas is detailed. The Fokker-Planck collision operator is employed in the continuous approximation and electric fields (considered external) are included in the equation. Bremsstrahlung processes are not treated. Comparisons with analytic and Monte Carlo results are given. Fits to deposition profiles and energy scaling are proposed and discussed for monoenergetic and Maxwellian sources in the range, 0 to 150 keV, with and without uniform fields. The techniques employed to track electrons are generally useful in situations where the background plasma temperature is an order of magnitude smaller than the electron energy and collective plasma effects are negligible. We have used the approach successfully in laser pellet implosion applications.

  12. One-dimensional spin-orbit interferometer

    NASA Astrophysics Data System (ADS)

    Li, Tommy; Sushkov, Oleg P.

    2013-04-01

    We demonstrate that the combination of an external magnetic field and the intrinsic spin-orbit interaction results in nonadiabatic precession of the electron spin after transmission through a quantum point contact (QPC). We suggest that this precession may be observed in a device consisting of two QPCs situated in series. The pattern of resonant peaks in the transmission is strongly influenced by the non-Abelian phase resulting from this precession. Moreover, an unusual type of resonance which is associated with suppressed, rather than enhanced, transmission (i.e., antiresonance) emerges in the strongly nonadiabatic regime. The shift in the resonant transmission peaks is dependent on the spin-orbit interaction and therefore offers a way to directly measure these interactions in a ballistic one-dimensional system.

  13. Unitary equivalent classes of one-dimensional quantum walks

    NASA Astrophysics Data System (ADS)

    Ohno, Hiromichi

    2016-09-01

    This study investigates unitary equivalent classes of one-dimensional quantum walks. We prove that one-dimensional quantum walks are unitary equivalent to quantum walks of Ambainis type and that translation-invariant one-dimensional quantum walks are Szegedy walks. We also present a necessary and sufficient condition for a one-dimensional quantum walk to be a Szegedy walk.

  14. Numerical investigation of one-dimensional heat-flux calculations

    NASA Astrophysics Data System (ADS)

    Boyd, C. F.; Howell, A.

    1994-10-01

    New computer codes to determine the heat transfer rate from wind tunnel model surface temperature measurements have been developed for use in the Navy's Hypervelocity Wind Tunnel No. 9 (Tunnel 9). The existing code, which assumes one-dimensional (1D) conduction in a Cartesian coordinate system, accurately predicts 1D heat-flux when applied to flat or nearly flat geometries. Heating rates are overpredicted when the code is applied to cylindrical, spherical, and conical geometries. The over-prediction increases with larger test times and smaller radius of curvature. Heating rates are also over-predicted when the code is applied under a two-dimensional (2D) heating load that varies linearly in space. This over-prediction increases with larger test times and larger spatial gradient of heat-flux but is small for typical Tunnel 9 applications. Two new computer codes, which assume 1D conduction in cylindrical and spherical coordinates, accurately predict 1D heat-flux applied to cylindrical, spherical, and conical geometries. These two codes are online for use as a tool in evaluating heat transfer from Tunnel 9 data.

  15. Using the NASA GRC Sectored-One-Dimensional Combustor Simulation

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.; Mehta, Vishal R.

    2014-01-01

    The document is a user manual for the NASA GRC Sectored-One-Dimensional (S-1-D) Combustor Simulation. It consists of three sections. The first is a very brief outline of the mathematical and numerical background of the code along with a description of the non-dimensional variables on which it operates. The second section describes how to run the code and includes an explanation of the input file. The input file contains the parameters necessary to establish an operating point as well as the associated boundary conditions (i.e. how it is fed and terminated) of a geometrically configured combustor. It also describes the code output. The third section describes the configuration process and utilizes a specific example combustor to do so. Configuration consists of geometrically describing the combustor (section lengths, axial locations, and cross sectional areas) and locating the fuel injection point and flame region. Configuration requires modifying the source code and recompiling. As such, an executable utility is included with the code which will guide the requisite modifications and insure that they are done correctly.

  16. Exciton quasicondensation in one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Werman, Yochai; Berg, Erez

    2015-06-01

    Two Luttinger liquids, with an equal density and opposite sign of charge carriers, may exhibit enhanced excitonic correlations. We term such a system an exciton quasicondensate, with a possible realization being two parallel oppositely doped quantum wires, coupled by repulsive Coulomb interactions. We show that this quasiexciton condensate can be stabilized in an extended range of parameters, in both spinless and spinful systems. We calculate the interwire tunneling current-voltage characteristic, and find that a negative differential conductance is a signature of excitonic correlations. For spinful electrons, the excitonic regime is shown to be distinct from the usual quasi-long-range ordered Wigner crystal phase characterized by power-law density wave correlations. The two phases can be clearly distinguished through their interwire tunneling current-voltage characteristics. In the quasiexciton condensate regime the tunneling conductivity diverges at low temperatures and voltages, whereas in the Wigner crystal it is strongly suppressed. Both the Wigner crystal and the excitonic regime are characterized by a divergent Coulomb drag at low temperature. Finally, metallic carbon nanotubes are considered as a special case of such a one-dimensional setup, and it is shown that exciton condensation is favorable due to the additional valley degree of freedom.

  17. One-dimensional model of inertial pumping.

    PubMed

    Kornilovitch, Pavel E; Govyadinov, Alexander N; Markel, David P; Torniainen, Erik D

    2013-02-01

    A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location. PMID:23496615

  18. A one dimensional model of population growth

    NASA Astrophysics Data System (ADS)

    Ribeiro, Fabiano L.; Ribeiro, Kayo N.

    2015-09-01

    In this work, a one dimensional population growth model is proposed. The model, based on the cooperative and competitive individual-individual distance-dependent interaction, allows us to get a full analytical solution. With this analytical approach, it was possible to investigate the dynamics of the population according to some parameters, as intrinsic growth rate, strength of the interaction between individuals, and the distance-dependent interaction. As a consequence of the individuals' interaction, a rich phase diagram to which the population has access was observed. The phases observed are: convergence to carrying capacity, exponential growth, divergence at finite time, and extinction. Moreover, it was also observed that some phases are strictly dependent on the initial condition. For instance, in the cooperative regime with negative intrinsic growth rate, the population can diverge or become extinct according to the initial population size. The phases accessible to the population can be seen as a macroscopic behavior which emerges from the interaction among the individuals (the microscopic level).

  19. Transport in a one-dimensional hyperconductor

    NASA Astrophysics Data System (ADS)

    Plamadeala, Eugeniu; Mulligan, Michael; Nayak, Chetan

    2016-03-01

    We define a "hyperconductor" to be a material whose electrical and thermal dc conductivities are infinite at zero temperature and finite at any nonzero temperature. The low-temperature behavior of a hyperconductor is controlled by a quantum critical phase of interacting electrons that is stable to all potentially gap-generating interactions and potentially localizing disorder. In this paper, we compute the low-temperature dc and ac electrical and thermal conductivities in a one-dimensional hyperconductor, studied previously by the present authors, in the presence of both disorder and umklapp scattering. We identify the conditions under which the transport coefficients are finite, which allows us to exhibit examples of violations of the Wiedemann-Franz law. The temperature dependence of the electrical conductivity, which is characterized by the parameter ΔX, is a power law, σ ∝1 /T1 -2 (2 -ΔX) when ΔX≥2 , down to zero temperature when the Fermi surface is commensurate with the lattice. There is a surface in parameter space along which ΔX=2 and ΔX≈2 for small deviations from this surface. In the generic (incommensurate) case with weak disorder, such scaling is seen at high temperatures, followed by an exponential increase of the conductivity lnσ ˜1 /T at intermediate temperatures and, finally, σ ∝1 /T2 -2 (2 -ΔX) at the lowest temperatures. In both cases, the thermal conductivity diverges at low temperatures.

  20. One-dimensional model of inertial pumping.

    PubMed

    Kornilovitch, Pavel E; Govyadinov, Alexander N; Markel, David P; Torniainen, Erik D

    2013-02-01

    A one-dimensional model of inertial pumping is introduced and solved. The pump is driven by a high-pressure vapor bubble generated by a microheater positioned asymmetrically in a microchannel. The bubble is approximated as a short-term impulse delivered to the two fluidic columns inside the channel. Fluid dynamics is described by a Newton-like equation with a variable mass, but without the mass derivative term. Because of smaller inertia, the short column refills the channel faster and accumulates a larger mechanical momentum. After bubble collapse the total fluid momentum is nonzero, resulting in a net flow. Two different versions of the model are analyzed in detail, analytically and numerically. In the symmetrical model, the pressure at the channel-reservoir connection plane is assumed constant, whereas in the asymmetrical model it is reduced by a Bernoulli term. For low and intermediate vapor bubble pressures, both models predict the existence of an optimal microheater location. The predicted net flow in the asymmetrical model is smaller by a factor of about 2. For unphysically large vapor pressures, the asymmetrical model predicts saturation of the effect, while in the symmetrical model net flow increases indefinitely. Pumping is reduced by nonzero viscosity, but to a different degree depending on the microheater location.

  1. The one-dimensional Gross-Pitaevskii equation and its some excitation states

    SciTech Connect

    Prayitno, T. B.

    2015-04-16

    We have derived some excitation states of the one-dimensional Gross-Pitaevskii equation coupled by the gravitational potential. The methods that we have used here are taken by pursuing the recent work of Kivshar et. al. by considering the equation as a macroscopic quantum oscillator. To obtain the states, we have made the appropriate transformation to reduce the three-dimensional Gross-Pitaevskii equation into the one-dimensional Gross-Pitaevskii equation and applying the time-independent perturbation theory in the general solution of the one-dimensional Gross-Pitaevskii equation as a linear superposition of the normalized eigenfunctions of the Schrödinger equation for the harmonic oscillator potential. Moreover, we also impose the condition by assuming that some terms in the equation should be so small in order to preserve the use of the perturbation method.

  2. One dimensional modeling of blood flow in large networks

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofei; Lagree, Pierre-Yves; Fullana, Jose-Maria; Lorthois, Sylvie; Institut de Mecanique des Fluides de Toulouse Collaboration

    2014-11-01

    A fast and valid simulation of blood flow in large networks of vessels can be achieved with a one-dimensional viscoelastic model. In this paper, we developed a parallel code with this model and computed several networks: a circle of arteries, a human systemic network with 55 arteries and a vascular network of mouse kidney with more than one thousand segments. The numerical results were verified and the speedup of parallel computing was tested on multi-core computers. The evolution of pressure distributions in all the networks were visualized and we can see clearly the propagation patterns of the waves. This provides us a convenient tool to simulate blood flow in networks.

  3. TOPAZ - the transient one-dimensional pipe flow analyzer: equations and numerics

    SciTech Connect

    Winters, W.S.

    1985-12-01

    TOPAZ is a ''user friendly'' computer code for modeling the one-dimensional, transient physics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. This report, the third in a series of reports documenting TOPAZ, deals exclusively with governing equations, numerical methods, and code architecture.

  4. A collision history-based approach to Sensitivity/Perturbation calculations in the continuous energy Monte Carlo code SERPENT

    SciTech Connect

    Giuseppe Palmiotti

    2015-05-01

    In this work, the implementation of a collision history-based approach to sensitivity/perturbation calculations in the Monte Carlo code SERPENT is discussed. The proposed methods allow the calculation of the eects of nuclear data perturbation on several response functions: the eective multiplication factor, reaction rate ratios and bilinear ratios (e.g., eective kinetics parameters). SERPENT results are compared to ERANOS and TSUNAMI Generalized Perturbation Theory calculations for two fast metallic systems and for a PWR pin-cell benchmark. New methods for the calculation of sensitivities to angular scattering distributions are also presented, which adopts fully continuous (in energy and angle) Monte Carlo estimators.

  5. Bulk-edge correspondence of one-dimensional quantum walks

    NASA Astrophysics Data System (ADS)

    Cedzich, C.; Grünbaum, F. A.; Stahl, C.; Velázquez, L.; Werner, A. H.; Werner, R. F.

    2016-05-01

    We outline a theory of symmetry protected topological phases of one-dimensional quantum walks. We assume spectral gaps around the symmetry-distinguished points +1 and ‑1, in which only discrete eigenvalues are allowed. The phase classification by integer or binary indices extends the classification known for translation invariant systems in terms of their band structure. However, our theory requires no translation invariance whatsoever, and the indices we define in this general setting are invariant under arbitrary symmetric local perturbations, even those that cannot be continuously contracted to the identity. More precisely we define two indices for every walk, characterizing the behavior far to the right and far to the left, respectively. Their sum is a lower bound on the number of eigenstates at +1 and ‑1. For a translation invariant system the indices add up to zero, so one of them already characterizes the phase. By joining two bulk phases with different indices we get a walk in which the right and left indices no longer cancel, so the theory predicts bound states at +1 or ‑1. This is a rigorous statement of bulk-edge correspondence. The results also apply to the Hamiltonian case with a single gap at zero.

  6. Decay of Bogoliubov excitations in one-dimensional Bose gases

    NASA Astrophysics Data System (ADS)

    Ristivojevic, Zoran; Matveev, K. A.

    2016-07-01

    We study the decay of Bogoliubov quasiparticles in one-dimensional Bose gases. Starting from the hydrodynamic Hamiltonian, we develop a microscopic theory that enables one to systematically study both the excitations and their decay. At zero temperature, the leading mechanism of decay of a quasiparticle is disintegration into three others. We find that low-energy quasiparticles (phonons) decay with the rate that scales with the seventh power of momentum, whereas the rate of decay of the high-energy quasiparticles does not depend on momentum. In addition, our approach allows us to study analytically the quasiparticle decay in the whole crossover region between the two limiting cases. When applied to integrable models, including the Lieb-Liniger model of bosons with contact repulsion, our theory confirms the absence of the decay of quasiparticle excitations. We account for two types of integrability-breaking perturbations that enable finite decay: three-body interaction between the bosons and two-body interaction of finite range.

  7. TOPAZ - the transient one-dimensional pipe flow analyzer: user's manual

    SciTech Connect

    Winters, W.S.

    1985-07-01

    TOPAZ is a ''user friendly'' computer code for modeling the one-dimensional-transient physics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. This document serves as a user's manual for the code, and should provide potential users with enough information to take advantage of many of the code's capabilities. Details regarding equations and numerics, example problems, applications, and modeling assumptions will be discussed in companion documents.

  8. Efficient technique for the numerical solution of the one-dimensional inverse problem of heat conduction

    NASA Astrophysics Data System (ADS)

    Blackwell, B. F.

    1981-06-01

    A very efficient numerical technique has been developed to solve the one-dimensional inverse problem of heat conduction. The Gauss elimination algorithm for solving the tridiagonal system of linear algebraic equations associated with most implicit heat conduction codes is specialized to the inverse problem. When compared to the corresponding direct problem, the upper limit in additional computation time generally does not exceed 27-36%. The technique can be adapted to existing one-dimensional implicit heat conduction codes with minimal effort and applied to difference equations obtained from finite-difference, finite-element, finite control volume, or similar techniques, provided the difference equations are tridiagonal in form. It is also applicable to the nonlinear case in which thermal properties are temperature-dependent and is valid for one-dimensional radial cylindrical and spherical geometries as well as composite bodies. The calculations reported here were done by modifying a one-dimensional implicit (direct) heat conduction code. Program changes consisted of 13 additional lines of FORTRAN coding.

  9. Asymmetric target patterns in one-dimensional oscillatory media with genuine nonlocal coupling.

    PubMed

    Plenge, F; Varela, H; Krischer, K

    2005-05-20

    We report the observation of a self-organized asymmetric wave source in a one-dimensional (1D) electrochemical system, namely, the hydrogen oxidation reaction on Pt in the presence of poisons. Numerical simulations reveal that the nonlocal migration coupling is crucial for the endogenous persistence of the perturbation that causes the asymmetry. Experiments and simulations agree perfectly for the regular and irregular variant of these asymmetric waves, manifesting the existence of nonlocal coupling induced patterns also in physical systems.

  10. Numerical experimentation on spherically symmetric one-dimensional magnetohydrodynamic /MHD/ wave propagation

    NASA Technical Reports Server (NTRS)

    Han, S. M.; Wu, S. T.; Nakagawa, Y.

    1982-01-01

    Radial propagation of one-dimensional magnetohydrodynamic (MHD) waves are analyzed numerically on the basis of the Implicit-Continuous-Fluid-Eulerian (ICE) scheme. Accuracy of the numerical method and other properties are tested through the study of MHD wave propagation. The three different modes of MHD waves (i.e., fast-, slow- and Alfven (transverse) mode) are generated by applying physically consistent boundary perturbations derived from MHD compatibility relations. It is shown that the resulting flow following these waves depend upon the relative configurations of the initial magnetic field and boundary perturbations.

  11. Study on longitudinal dispersion relation in one-dimensional relativistic plasma: Linear theory and Vlasov simulation

    SciTech Connect

    Zhang, H.; Wu, S. Z.; Zhou, C. T.; He, X. T.; Zhu, S. P.

    2013-09-15

    The dispersion relation of one-dimensional longitudinal plasma waves in relativistic homogeneous plasmas is investigated with both linear theory and Vlasov simulation in this paper. From the Vlasov-Poisson equations, the linear dispersion relation is derived for the proper one-dimensional Jüttner distribution. Numerically obtained linear dispersion relation as well as an approximate formula for plasma wave frequency in the long wavelength limit is given. The dispersion of longitudinal wave is also simulated with a relativistic Vlasov code. The real and imaginary parts of dispersion relation are well studied by varying wave number and plasma temperature. Simulation results are in agreement with established linear theory.

  12. Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morris, Christopher I.

    2002-01-01

    . While such a nozzle is a considerable idealization, it is clear that nozzle design and optimization will play a critical role in whether the performance potential of PDREs can be effectively realized in practice. In order to study PDRE nozzle issues with greater accuracy, a quasi-one-dimensional, finite-rate chemistry CFD code has been developed by the author. Comparisons of the code with both the previous MOC model and experimental data from Stanford University are reported. The effect of constant-gamma and finite-rate chemistry assumptions on the flowfield and performance is examined. Parametric studies of the effect of nozzle throat size and expansion ratio, at various blowdown pressure ratios, are reported.

  13. One-dimensional reacting gas nonequilibrium performance program

    NASA Technical Reports Server (NTRS)

    Frey, H. M.; Kliegel, J. R.

    1968-01-01

    Computer program calculates the inviscid one-dimensional equilibrium, frozen, and nonequilibrium nozzle expansion of gaseous propellant exhaust mixtures containing the elements - carbon, hydrogen, oxygen, nitrogen, fluorine and chlorine. The program performs calculations for conical nozzles only.

  14. Extending the Analysis of One-Dimensional Motion.

    ERIC Educational Resources Information Center

    Canderle, Luis H.

    1999-01-01

    Proposes that introductory physics courses extend the analysis of one-dimensional motion to a more sophisticated level. Gives four experimental setups and graphical analysis of the distance, velocity, and acceleration in the vertical and horizontal directions. (WRM)

  15. Asymptotic formula for eigenvalues of one dimensional Dirac system

    NASA Astrophysics Data System (ADS)

    Ulusoy, Ismail; Penahlı, Etibar

    2016-06-01

    In this paper, we study the spectral problem for one dimensional Dirac system with Dirichlet boundary conditions. By using Counting lemma, we give an asymptotic formulas of eigenvalues of Dirac system.

  16. One dimensional time-to-explode (ODTX) in HMX spheres

    SciTech Connect

    Breshears, D.

    1997-06-02

    In a series of papers researchers at Lawrence Livermore National Laboratory (LLNL) have reported measurements of the time to explosion in spheres of various high explosives following a rapid, uniform increase in the surface temperature of the sphere. Due to the spherical symmetry, the time-dependent properties of the explosive (temperature, chemical composition, etc.) are functions of the radial spatial coordinate only; thus the name one-dimensional time-to-explosion (ODTX). The LLNL researchers also report an evolving series of computational modeling results for the ODTX experiments, culminating in those obtained using a sophisticated heat transfer code incorporating accurate descriptions of chemical reaction. Although the chemical reaction mechanism used to describe HMX decomposition is quite simple, the computational results agree very well with the experimental data. In addition to reproducing the magnitude and temperature dependence of the measured times to explosion, the computational results also agree with the results of post reaction visual inspection. The ODTX experiments offer a near-ideal example of a transport process (heat transfer in this case) tightly coupled with chemical reaction. The LLNL computational model clearly captures the important features of the ODTX experiments. An obvious question of interest is to what extent the model and/or its individual components (specifically the chemical reaction mechanism) are applicable to other experimental scenarios. Valid exploration of this question requires accurate understanding of (1) the experimental scenario addressed by the LLNL model and (2) details of the application of the model. The author reports here recent work addressing points (1) and (2).

  17. Spin-Lattice Order in One-Dimensional Conductors: Beyond the RKKY Effect.

    PubMed

    Schecter, Michael; Rudner, Mark S; Flensberg, Karsten

    2015-06-19

    We investigate magnetic order in a lattice of classical spins coupled to an isotropic gas of one-dimensional conduction electrons via local exchange interactions. The frequently discussed Ruderman-Kittel-Kasuya-Yosida effective exchange model for this system predicts that spiral order is always preferred. Here we consider the problem nonperturbatively, and find that such order vanishes above a critical value of the exchange coupling that depends strongly on the lattice spacing. The critical coupling tends to zero as the lattice spacing becomes commensurate with the Fermi wave vector, signaling the breakdown of the perturbative Ruderman-Kittel-Kasuya-Yosida picture, and spiral order, even at weak coupling. We provide the exact phase diagram for arbitrary exchange coupling and lattice spacing, and discuss its stability. Our results shed new light on the problem of utilizing a spiral spin-lattice state to drive a one-dimensional superconductor into a topological phase.

  18. Spin-Lattice Order in One-Dimensional Conductors: Beyond the RKKY Effect.

    PubMed

    Schecter, Michael; Rudner, Mark S; Flensberg, Karsten

    2015-06-19

    We investigate magnetic order in a lattice of classical spins coupled to an isotropic gas of one-dimensional conduction electrons via local exchange interactions. The frequently discussed Ruderman-Kittel-Kasuya-Yosida effective exchange model for this system predicts that spiral order is always preferred. Here we consider the problem nonperturbatively, and find that such order vanishes above a critical value of the exchange coupling that depends strongly on the lattice spacing. The critical coupling tends to zero as the lattice spacing becomes commensurate with the Fermi wave vector, signaling the breakdown of the perturbative Ruderman-Kittel-Kasuya-Yosida picture, and spiral order, even at weak coupling. We provide the exact phase diagram for arbitrary exchange coupling and lattice spacing, and discuss its stability. Our results shed new light on the problem of utilizing a spiral spin-lattice state to drive a one-dimensional superconductor into a topological phase. PMID:26197005

  19. Spin-Lattice Order in One-Dimensional Conductors: Beyond the RKKY Effect

    NASA Astrophysics Data System (ADS)

    Schecter, Michael; Rudner, Mark S.; Flensberg, Karsten

    2015-06-01

    We investigate magnetic order in a lattice of classical spins coupled to an isotropic gas of one-dimensional conduction electrons via local exchange interactions. The frequently discussed Ruderman-Kittel-Kasuya-Yosida effective exchange model for this system predicts that spiral order is always preferred. Here we consider the problem nonperturbatively, and find that such order vanishes above a critical value of the exchange coupling that depends strongly on the lattice spacing. The critical coupling tends to zero as the lattice spacing becomes commensurate with the Fermi wave vector, signaling the breakdown of the perturbative Ruderman-Kittel-Kasuya-Yosida picture, and spiral order, even at weak coupling. We provide the exact phase diagram for arbitrary exchange coupling and lattice spacing, and discuss its stability. Our results shed new light on the problem of utilizing a spiral spin-lattice state to drive a one-dimensional superconductor into a topological phase.

  20. An exact solution of solute transport by one-dimensional random velocity fields

    USGS Publications Warehouse

    Cvetkovic, V.D.; Dagan, G.; Shapiro, A.M.

    1991-01-01

    The problem of one-dimensional transport of passive solute by a random steady velocity field is investigated. This problem is representative of solute movement in porous media, for example, in vertical flow through a horizontally stratified formation of variable porosity with a constant flux at the soil surface. Relating moments of particle travel time and displacement, exact expressions for the advection and dispersion coefficients in the Focker-Planck equation are compared with the perturbation results for large distances. The first- and second-order approximations for the dispersion coefficient are robust for a lognormal velocity field. The mean Lagrangian velocity is the harmonic mean of the Eulerian velocity for large distances. This is an artifact of one-dimensional flow where the continuity equation provides for a divergence free fluid flux, rather than a divergence free fluid velocity. ?? 1991 Springer-Verlag.

  1. One-dimensional rainbow technique using Fourier domain filtering.

    PubMed

    Wu, Yingchun; Promvongsa, Jantarat; Wu, Xuecheng; Cen, Kefa; Grehan, Gerard; Saengkaew, Sawitree

    2015-11-16

    Rainbow refractometry can measure the refractive index and the size of a droplet simultaneously. The refractive index measurement is extracted from the absolute rainbow scattering angle. Accordingly, the angular calibration is vital for accurate measurements. A new optical design of the one-dimensional rainbow technique is proposed by using a one-dimensional spatial filter in the Fourier domain. The relationship between the scattering angle and the CCD pixel of a recorded rainbow image can be accurately determined by a simple calibration. Moreover, only the light perpendicularly incident on the lens in the angle (φ) direction is selected, which exactly matches the classical inversion algorithm used in rainbow refractometry. Both standard and global one-dimensional rainbow techniques are implemented with the proposed optical design, and are successfully applied to measure the refractive index and the size of a line of n-heptane droplets.

  2. Some topological states in one-dimensional cold atomic systems

    SciTech Connect

    Mei, Feng; Zhang, Dan-Wei; Zhu, Shi-Liang

    2015-07-15

    Ultracold atoms trapped in optical lattices nowadays have been widely used to mimic various models from condensed-matter physics. Recently, many great experimental progresses have been achieved for producing artificial magnetic field and spin–orbit coupling in cold atomic systems, which turn these systems into a new platform for simulating topological states. In this paper, we give a review focusing on quantum simulation of topologically protected soliton modes and topological insulators in one-dimensional cold atomic system. Firstly, the recent achievements towards quantum simulation of one-dimensional models with topological non-trivial states are reviewed, including the celebrated Jackiw–Rebbi model and Su–Schrieffer–Heeger model. Then, we will introduce a dimensional reduction method for systematically constructing high dimensional topological states in lower dimensional models and review its applications on simulating two-dimensional topological insulators in one-dimensional optical superlattices.

  3. One-dimensional rainbow technique using Fourier domain filtering.

    PubMed

    Wu, Yingchun; Promvongsa, Jantarat; Wu, Xuecheng; Cen, Kefa; Grehan, Gerard; Saengkaew, Sawitree

    2015-11-16

    Rainbow refractometry can measure the refractive index and the size of a droplet simultaneously. The refractive index measurement is extracted from the absolute rainbow scattering angle. Accordingly, the angular calibration is vital for accurate measurements. A new optical design of the one-dimensional rainbow technique is proposed by using a one-dimensional spatial filter in the Fourier domain. The relationship between the scattering angle and the CCD pixel of a recorded rainbow image can be accurately determined by a simple calibration. Moreover, only the light perpendicularly incident on the lens in the angle (φ) direction is selected, which exactly matches the classical inversion algorithm used in rainbow refractometry. Both standard and global one-dimensional rainbow techniques are implemented with the proposed optical design, and are successfully applied to measure the refractive index and the size of a line of n-heptane droplets. PMID:26698532

  4. Pose estimation for one-dimensional object with general motion

    NASA Astrophysics Data System (ADS)

    Liu, Jinbo; Song, Ge; Zhang, Xiaohu

    2014-11-01

    Our primary interest is in real-time one-dimensional object's pose estimation. In this paper, a method to estimate general motion one-dimensional object's pose, that is, the position and attitude parameters, using a single camera is proposed. Centroid-movement is necessarily continuous and orderly in temporal space, which means it follows at least approximately certain motion law in a short period of time. Therefore, the centroid trajectory in camera frame can be described as a combination of temporal polynomials. Two endpoints on one-dimensional object, A and B, at each time are projected on the corresponding image plane. With the relationship between A, B and centroid C, we can obtain a linear equation system related to the temporal polynomials' coefficients, in which the camera has been calibrated and the image coordinates of A and B are known. Then in the cases that object moves continuous in natural temporal space within the view of a stationary camera, the position of endpoints on the one-dimensional object can be located and also the attitude can be estimated using two end points. Moreover the position of any other point aligned on one-dimensional object can also be solved. Scene information is not needed in the proposed method. If the distance between the endpoints is not known, a scale factor between the object's real positions and the estimated results will exist. In order to improve the algorithm's performance from accuracy and robustness, we derive a pain of linear and optimal algorithms. Simulations' and experiments' results show that the method is valid and robust with respect to various Gaussian noise levels. The paper's work contributes to making self-calibration algorithms using one-dimensional objects applicable to practice. Furthermore, the method can also be used to estimate the pose and shape parameters of parallelogram, prism or cylinder objects.

  5. Enforced one-dimensional photoconductivity in core-cladding hexabenzocoronenes.

    PubMed

    Cohen, Yaron S; Xiao, Shengxiong; Steigerwald, Michael L; Nuckolls, Colin; Kagan, Cherie R

    2006-12-01

    Photoconductivity in contorted hexabenzocoronene liquid crystals is found to be exclusively one-dimensional. Spectroscopic measurements and density functional theory support the existence of two pi-systems attributed to a low-energy radialene-core and higher energy out-of-plane alkoxyphenyl rings. Persistent photocurrents, measured as a function of field, channel length, and intensity, fit a stretched exponential characteristic of intracolumnar transport, restricted through the radialene-core by the alkoxyphenyl-cladding. Bimolecular recombination is enhanced with increasing carrier concentration by the system's one-dimensionality.

  6. Explicit solutions of one-dimensional total variation problem

    NASA Astrophysics Data System (ADS)

    Makovetskii, Artyom; Voronin, Sergei; Kober, Vitaly

    2015-09-01

    This work deals with denosing of a one-dimensional signal corrupted by additive white Gaussian noise. A common way to solve the problem is to utilize the total variation (TV) method. Basically, the TV regularization minimizes a functional consisting of the sum of fidelity and regularization terms. We derive explicit solutions of the one-dimensional TV regularization problem that help us to restore noisy signals with a direct, non-iterative algorithm. Computer simulation results are provided to illustrate the performance of the proposed algorithm for restoration of noisy signals.

  7. Hybrid surface-relief/volume one dimensional holographic gratings

    NASA Astrophysics Data System (ADS)

    Lucchetta, D. E.; Spegni, P.; Di Donato, A.; Simoni, F.; Castagna, R.

    2015-04-01

    Many one dimensional optically patterned photopolymers exist as surface relief or volume phase gratings. However, as far as we know, holographically recorded acrylate-based gratings in which both configurations are present are not described in literature. In this work we report a two steps fabrication process in which a large-area high-resolution hybrid volume/surface relief grating phase gratings is created in a thin film of multiacrylate material spinned on a proper designed substrate. Optical and morphological investigations, made on the optically patterned area, confirm the presence of a one dimensional double (surface relief and Bragg volume phase) periodic structure.

  8. Lateral electronic screening in quasi-one-dimensional plasmons

    NASA Astrophysics Data System (ADS)

    Lichtenstein, T.; Tegenkamp, C.; Pfnür, H.

    2016-09-01

    The properties of one-dimensional (1D) plasmons are rather unexplored. We investigated the plasmonic collective excitations, measured as one-dimensional plasmon dispersions with electron energy loss spectroscopy, highly resolved both in energy and lateral momentum, for both phases of Au induced chains on stepped Si(553) substrates. We observe 1D dispersions that are strongly influenced by the lateral chain width and by the interchain coupling. Indications for the existence of two different plasmons originating from two surface bands of the systems are given for the low coverage phase.

  9. One-dimensional fast migration of vacancy clusters in metals

    SciTech Connect

    Matsukawa, Yoshitaka; Zinkle, Steven J

    2007-01-01

    The migration of point defects, e.g. crystal lattice vacancies and self-interstitial atoms (SIAs), typically occurs through three-dimensional (3-D) random walk. However, when vacancies and SIAs agglomerate with like defects forming clusters, the migration mode may change. Recently, atomic-scale computer simulations using molecular dynamics (MD) codes have reported that nanometer-sized two-dimensional (2-D) clusters of SIAs exhibit one-dimensional (1-D) fast migration1-7. The 1-D migration mode transports the entire cluster containing several tens of SIAs with a mobility comparable to single SIAs3. This anisotropic migration of SIA clusters can have a significant impact on the evolution of a material fs neutron-irradiation damage microstructure, which dominates the material fs lifetime in nuclear reactor environments8-9. This is also proposed to be a key physical mechanism for the self-organization of nanometer-sized sessile vacancy cluster arrays10-13. Given these findings for SIA clusters, a fundamental question is whether the 1-D migration mode is also possible for 2-D clusters of vacancies. Preceding MD results predicted that 1-D migration of vacancy clusters is possible in body-centered cubic (bcc) iron, but not in face-centered cubic (fcc) copper2. Previous experimental studies have reported 1-D migration of SIA clusters14, but there have been no observations of 1-D vacancy cluster migration. Here we present the first experimental transmission electron microscopy (TEM) dynamic observation demonstrating the 1-D migration of vacancy clusters in fcc gold. It was found that the mobility of the vacancy clusters via the 1-D migration is much higher than single vacancies via 3-D random walk and comparable to single SIAs via 3-D random walk. Hence, the mobility of the glissile clusters is not associated with the character of their constituent point defects. Dynamic conversion of a planar vacancy loop into a 3-D stacking fault tetrahedron geometry was also observed.

  10. Teaching Module for One-Dimensional, Transient Conduction.

    ERIC Educational Resources Information Center

    Ribando, Robert J.; O'Leary, Gerald W.

    1998-01-01

    Describes a PC-based teaching module designed to instruct engineering students in transient one-dimensional conduction heat transfer analysis. The discussion considers problem formulation, nondimensionalization, discretization, numerical stability and the time-step restriction, program operation, and program verification. (MES)

  11. Exact Results for One Dimensional Fluids Through Functional Integration

    NASA Astrophysics Data System (ADS)

    Fantoni, Riccardo

    2016-06-01

    We review some of the exactly solvable one dimensional continuum fluid models of equilibrium classical statistical mechanics under the unified setting of functional integration in one dimension. We make some further developments and remarks concerning fluids with penetrable particles. We then apply our developments to the study of the Gaussian core model for which we are unable to find a well defined thermodynamics.

  12. Approximate Approaches to the One-Dimensional Finite Potential Well

    ERIC Educational Resources Information Center

    Singh, Shilpi; Pathak, Praveen; Singh, Vijay A.

    2011-01-01

    The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m[subscript i]) is taken to be distinct from mass outside (m[subscript o]). A relevant parameter is the mass…

  13. Underwater striling engine design with modified one-dimensional model

    NASA Astrophysics Data System (ADS)

    Li, Daijin; Qin, Kan; Luo, Kai

    2015-05-01

    Stirling engines are regarded as an efficient and promising power system for underwater devices. Currently, many researches on one-dimensional model is used to evaluate thermodynamic performance of Stirling engine, but in which there are still some aspects which cannot be modeled with proper mathematical models such as mechanical loss or auxiliary power. In this paper, a four-cylinder double-acting Stirling engine for Unmanned Underwater Vehicles (UUVs) is discussed. And a one-dimensional model incorporated with empirical equations of mechanical loss and auxiliary power obtained from experiments is derived while referring to the Stirling engine computer model of National Aeronautics and Space Administration (NASA). The P-40 Stirling engine with sufficient testing results from NASA is utilized to validate the accuracy of this one-dimensional model. It shows that the maximum error of output power of theoretical analysis results is less than 18% over testing results, and the maximum error of input power is no more than 9%. Finally, a Stirling engine for UUVs is designed with Schmidt analysis method and the modified one-dimensional model, and the results indicate this designed engine is capable of showing desired output power.

  14. Underwater striling engine design with modified one-dimensional model

    NASA Astrophysics Data System (ADS)

    Li, Daijin; Qin, Kan; Luo, Kai

    2015-09-01

    Stirling engines are regarded as an efficient and promising power system for underwater devices. Currently, many researches on one-dimensional model is used to evaluate thermodynamic performance of Stirling engine, but in which there are still some aspects which cannot be modeled with proper mathematical models such as mechanical loss or auxiliary power. In this paper, a four-cylinder double-acting Stirling engine for Unmanned Underwater Vehicles (UUVs) is discussed. And a one-dimensional model incorporated with empirical equations of mechanical loss and auxiliary power obtained from experiments is derived while referring to the Stirling engine computer model of National Aeronautics and Space Administration (NASA). The P-40 Stirling engine with sufficient testing results from NASA is utilized to validate the accuracy of this one-dimensional model. It shows that the maximum error of output power of theoretical analysis results is less than 18% over testing results, and the maximum error of input power is no more than 9%. Finally, a Stirling engine for UUVs is designed with Schmidt analysis method and the modified one-dimensional model, and the results indicate this designed engine is capable of showing desired output power.

  15. Transition density of one-dimensional diffusion with discontinuous drift

    NASA Technical Reports Server (NTRS)

    Zhang, Weijian

    1990-01-01

    The transition density of a one-dimensional diffusion process with a discontinuous drift coefficient is studied. A probabilistic representation of the transition density is given, illustrating the close connections between discontinuities of the drift and Brownian local times. In addition, some explicit results are obtained based on the trivariate density of Brownian motion, its occupation, and local times.

  16. One-Dimensional SO2 Predictions for Duct Injection

    1993-10-05

    DIAN1D is a one-dimensional model that predicts SO2 absorption by slurry droplets injected into a flue gas stream with two-fluid atomizers. DIANUI is an interactive user interface for DIAN1D. It prepares the input file for DIAN1D from plant design specifications and process requirements.

  17. One-Dimensional Ising Model with "k"-Spin Interactions

    ERIC Educational Resources Information Center

    Fan, Yale

    2011-01-01

    We examine a generalization of the one-dimensional Ising model involving interactions among neighbourhoods of "k" adjacent spins. The model is solved by exploiting a connection to an interesting computational problem that we call ""k"-SAT on a ring", and is shown to be equivalent to the nearest-neighbour Ising model in the absence of an external…

  18. The Long Decay Model of One-Dimensional Projectile Motion

    ERIC Educational Resources Information Center

    Lattery, Mark Joseph

    2008-01-01

    This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are…

  19. Anomalous heat conduction in a one-dimensional ideal gas.

    PubMed

    Casati, Giulio; Prosen, Tomaz

    2003-01-01

    We provide firm convincing evidence that the energy transport in a one-dimensional gas of elastically colliding free particles of unequal masses is anomalous, i.e., the Fourier law does not hold. Our conclusions are confirmed by a theoretical and numerical analysis based on a Green-Kubo-type approach specialized to momentum-conserving lattices. PMID:12636549

  20. On one-dimensional velocity approximation for speed-dependent spectral line profiles

    NASA Astrophysics Data System (ADS)

    Kochanov, V. P.

    2013-05-01

    An application of one-dimensional velocity approach to calculation of speed-dependent spectral line profiles was considered. It was shown that a mean deviation of the line profile obtained within this approach from the line profile derived with integrating over three projections of an absorbing molecule's velocity does not exceed 1.1% at mass ratios of perturbing and absorbing molecules ≤9. Analytical approximate expressions for speed-dependent line profiles, including spectral line narrowing and mixing, were obtained for one- and three-dimensional velocity approaches.

  1. Modelling and calculation of flotation process in one-dimensional formulation

    NASA Astrophysics Data System (ADS)

    Amanbaev, Tulegen; Tilleuov, Gamidulla; Tulegenova, Bibigul

    2016-08-01

    In the framework of the assumptions of the mechanics of the multiphase media is constructed a mathematical model of the flotation process in the dispersed mixture of liquid, solid and gas phases, taking into account the degree of mineralization of the surface of the bubbles. Application of the constructed model is demonstrated on the example of one-dimensional stationary flotation and it is shown that the equations describing the process of ascent of the bubbles are singularly perturbed ("rigid"). The effect of size and concentration of bubbles and the volumetric content of dispersed particles on the flotation process are analyzed.

  2. Confined One Dimensional Harmonic Oscillator as a Two-Mode System

    SciTech Connect

    Gueorguiev, V G; Rau, A P; Draayer, J P

    2005-07-11

    The one-dimensional harmonic oscillator in a box problem is possibly the simplest example of a two-mode system. This system has two exactly solvable limits, the harmonic oscillator and a particle in a (one-dimensional) box. Each of the two limits has a characteristic spectral structure describing the two different excitation modes of the system. Near each of these limits, one can use perturbation theory to achieve an accurate description of the eigenstates. Away from the exact limits, however, one has to carry out a matrix diagonalization because the basis-state mixing that occurs is typically too large to be reproduced in any other way. An alternative to casting the problem in terms of one or the other basis set consists of using an ''oblique'' basis that uses both sets. Through a study of this alternative in this one-dimensional problem, we are able to illustrate practical solutions and infer the applicability of the concept for more complex systems, such as in the study of complex nuclei where oblique-basis calculations have been successful.

  3. Spatial coherence properties of one dimensional exciton-polariton condensates.

    PubMed

    Fischer, J; Savenko, I G; Fraser, M D; Holzinger, S; Brodbeck, S; Kamp, M; Shelykh, I A; Schneider, C; Höfling, S

    2014-11-14

    In this work, we combine a systematic experimental investigation of the power- and temperature-dependent evolution of the spatial coherence function, g^{(1)}(r), in a one dimensional exciton-polariton channel with a modern microscopic numerical theory based on a stochastic master equation approach. The spatial coherence function g^{(1)}(r) is extracted via high-precision Michelson interferometry, which allows us to demonstrate that in the regime of nonresonant excitation, the dependence g^{(1)}(r) reaches a saturation value with a plateau, which is determined by the intensity of the pump and effective temperature of the crystal lattice. The theory, which was extended to allow for treating incoherent excitation in a stochastic frame, matches the experimental data with good qualitative and quantitative agreement. This allows us to verify the prediction that the decay of the off-diagonal long-range order can be almost fully suppressed in one dimensional condensate systems.

  4. The one-dimensional Coulomb lattice fluid capacitor

    NASA Astrophysics Data System (ADS)

    Démery, Vincent; Dean, David S.; Hammant, Thomas C.; Horgan, Ronald R.; Podgornik, Rudolf

    2012-08-01

    The one-dimensional Coulomb lattice fluid in a capacitor configuration is studied. The model is formally exactly soluble via a transfer operator method within a field theoretic representation of the model. The only interactions present in the model are the one-dimensional Coulomb interaction between cations and anions and the steric interaction imposed by restricting the maximal occupancy at any lattice site to one particle. Despite the simplicity of the model, a wide range of intriguing physical phenomena arise, some of which are strongly reminiscent of those seen in experiments and numerical simulations of three-dimensional ionic liquid based capacitors. Notably, we find regimes where over-screening and density oscillations are seen near the capacitor plates. The capacitance is also shown to exhibit strong oscillations as a function of applied voltage. It is also shown that the corresponding mean-field theory misses most of these effects. The analytical results are confirmed by extensive numerical simulations.

  5. Fate of classical solitons in one-dimensional quantum systems.

    SciTech Connect

    Pustilnik, M.; Matveev, K. A.

    2015-11-23

    We study one-dimensional quantum systems near the classical limit described by the Korteweg-de Vries (KdV) equation. The excitations near this limit are the well-known solitons and phonons. The classical description breaks down at long wavelengths, where quantum effects become dominant. Focusing on the spectra of the elementary excitations, we describe analytically the entire classical-to-quantum crossover. We show that the ultimate quantum fate of the classical KdV excitations is to become fermionic quasiparticles and quasiholes. We discuss in detail two exactly solvable models exhibiting such crossover, the Lieb-Liniger model of bosons with weak contact repulsion and the quantum Toda model, and argue that the results obtained for these models are universally applicable to all quantum one-dimensional systems with a well-defined classical limit described by the KdV equation.

  6. Entanglement vs. gap for one-dimensional spin systems

    SciTech Connect

    Hastings, Matthew; Aharonov, Dorit; Gottesman, Daniel

    2008-01-01

    We study the relationship between entanglement and spectral gap for local Hamiltonians in one dimension. The area law for a one-dimensional system states that for the ground state, the entanglement of any interval is upper-bounded by a constant independent of the size of the interval. However, the possible dependence of the upper bound on the spectral gap {Delta} is not known, as the best known general upper bound is asymptotically much larger than the largest possible entropy of any model system previously constructed for small {Delta}. To help resolve this asymptotic behavior, we construct a family of one-dimensional local systems for which some intervals have entanglement entropy which is polynomial in 1/{Delta}, whereas previously studied systems had the entropy of all intervals bounded by a constant times log(1/{Delta}).

  7. Excitonic condensation in spatially separated one-dimensional systems

    SciTech Connect

    Abergel, D. S. L.

    2015-05-25

    We show theoretically that excitons can form from spatially separated one-dimensional ground state populations of electrons and holes, and that the resulting excitons can form a quasicondensate. We describe a mean-field Bardeen-Cooper-Schrieffer theory in the low carrier density regime and then focus on the core-shell nanowire giving estimates of the size of the excitonic gap for InAs/GaSb wires and as a function of all the experimentally relevant parameters. We find that optimal conditions for pairing include small overlap of the electron and hole bands, large effective mass of the carriers, and low dielectric constant of the surrounding media. Therefore, one-dimensional systems provide an attractive platform for the experimental detection of excitonic quasicondensation in zero magnetic field.

  8. One-dimensional Hubbard-Luttinger model for carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ishkhanyan, H. A.; Krainov, V. P.

    2015-06-01

    A Hubbard-Luttinger model is developed for qualitative description of one-dimensional motion of interacting Pi-conductivity-electrons in carbon single-wall nanotubes at low temperatures. The low-lying excitations in one-dimensional electron gas are described in terms of interacting bosons. The Bogolyubov transformation allows one to describe the system as an ensemble of non-interacting quasi-bosons. Operators of Fermi excitations and Green functions of fermions are introduced. The electric current is derived as a function of potential difference on the contact between a nanotube and a normal metal. Deviations from Ohm law produced by electron-electron short-range repulsion as well as by the transverse quantization in single-wall nanotubes are discussed. The results are compared with experimental data.

  9. Scaling properties of one-dimensional driven-dissipative condensates

    NASA Astrophysics Data System (ADS)

    He, Liang; Sieberer, Lukas M.; Altman, Ehud; Diehl, Sebastian

    2015-10-01

    We numerically investigate the scaling properties of a one-dimensional driven-dissipative condensate described by a stochastic complex Ginzburg-Landau equation (SCGLE). We directly extract the static and dynamical scaling exponents from the dynamics of the condensate's phase field, and find that both coincide with the ones of the one-dimensional Kardar-Parisi-Zhang (KPZ) equation. We furthermore calculate the spatial and the temporal two-point correlation functions of the condensate field itself. The decay of the temporal two-point correlator assumes a stretched-exponential form, providing further quantitative evidence for an effective KPZ description. Moreover, we confirm the observability of this nonequilibrium scaling for typical current experimental setups with exciton-polariton systems, if cavities with a reduced Q factor are used.

  10. Nonequilibrium statistical mechanics in one-dimensional bose gases

    NASA Astrophysics Data System (ADS)

    Baldovin, F.; Cappellaro, A.; Orlandini, E.; Salasnich, L.

    2016-06-01

    We study cold dilute gases made of bosonic atoms, showing that in the mean-field one-dimensional regime they support stable out-of-equilibrium states. Starting from the 3D Boltzmann-Vlasov equation with contact interaction, we derive an effective 1D Landau-Vlasov equation under the condition of a strong transverse harmonic confinement. We investigate the existence of out-of-equilibrium states, obtaining stability criteria similar to those of classical plasmas.

  11. On numerical modeling of one-dimensional geothermal histories

    USGS Publications Warehouse

    Haugerud, R.A.

    1989-01-01

    Numerical models of one-dimensional geothermal histories are one way of understanding the relations between tectonics and transient thermal structure in the crust. Such models can be powerful tools for interpreting geochronologic and thermobarometric data. A flexible program to calculate these models on a microcomputer is available and examples of its use are presented. Potential problems with this approach include the simplifying assumptions that are made, limitations of the numerical techniques, and the neglect of convective heat transfer. ?? 1989.

  12. Cooling of a One-Dimensional Bose Gas.

    PubMed

    Rauer, B; Grišins, P; Mazets, I E; Schweigler, T; Rohringer, W; Geiger, R; Langen, T; Schmiedmayer, J

    2016-01-22

    We experimentally study the dynamics of a degenerate one-dimensional Bose gas that is subject to a continuous outcoupling of atoms. Although standard evaporative cooling is rendered ineffective by the absence of thermalizing collisions in this system, we observe substantial cooling. This cooling proceeds through homogeneous particle dissipation and many-body dephasing, enabling the preparation of otherwise unexpectedly low temperatures. Our observations establish a scaling relation between temperature and particle number, and provide insights into equilibration in the quantum world.

  13. Beyond the Born approximation in one-dimensional profile reconstruction

    NASA Astrophysics Data System (ADS)

    Trantanella, Charles J.; Dudley, Donald G.; Nabulsi, Khalid A.

    1995-07-01

    A new method of one-dimensional profile reconstruction is presented. The method is based on an extension to the Born approximation and relates measurements of the scattered field to the Fourier transform of the slab profile. Since the Born and our new approximations are most valid at low frequency, we utilize superresolution to recover high-frequency information and then invert for the slab profile. Finally, we vary different parameters and examine the resulting reconstructions. approximation, profile reconstruction, superresolution.

  14. Superlensing properties of one-dimensional dielectric photonic crystals

    NASA Astrophysics Data System (ADS)

    Savo, Salvatore; di Gennaro, Emiliano; Andreone, Antonello

    2009-10-01

    We present the experimental observation of the superlensing effect in a slab of a one-dimensional photonic crystal made of tilted dielectric elements. We show that this flat lens can achieve subwavelength resolution in different frequency bands. We also demonstrate that the introduction of a proper corrugation on the lens surface can dramatically improve both the transmission and the resolution of the imaged signal.

  15. Defects in a nonlinear pseudo one-dimensional solid

    NASA Astrophysics Data System (ADS)

    Blanchet, Graciela B.; Fincher, C. R., Jr.

    1985-03-01

    These infrared studies of acetanilide together with the existence of two equivalent structures for the hydrogen-bonded chain suggest the possibility of a topological defect state rather than a Davydov soliton as suggested previously. Acetanilide is an example of a class of one-dimensional materials where solitons are a consequence of a twofold degenerate structure and the nonlinear dynamics of the hydrogen-bonded network.

  16. One-dimensional quantum pump simulated by cold atoms

    NASA Astrophysics Data System (ADS)

    Xiao, Yun-Chang; Zhu, Ming-Han; Liu, Zheng-Qin

    2015-05-01

    Quantum pump set up in one-dimensional (1D) channel was proposed by the cold atom simulation. The target pumping system is driven by the double time-dependent potentials. We investigated that the system can be achieved via the study of the cold atoms simulation. And by using the Floquet scattering method and the related transport theories in the mesoscopic systems, simulations of the pumping processes were presented in detail.

  17. Cryptography using multiple one-dimensional chaotic maps

    NASA Astrophysics Data System (ADS)

    Pareek, N. K.; Patidar, Vinod; Sud, K. K.

    2005-10-01

    Recently, Pareek et al. [Phys. Lett. A 309 (2003) 75] have developed a symmetric key block cipher algorithm using a one-dimensional chaotic map. In this paper, we propose a symmetric key block cipher algorithm in which multiple one-dimensional chaotic maps are used instead of a one-dimensional chaotic map. However, we also use an external secret key of variable length (maximum 128-bits) as used by Pareek et al. In the present cryptosystem, plaintext is divided into groups of variable length (i.e. number of blocks in each group is different) and these are encrypted sequentially by using randomly chosen chaotic map from a set of chaotic maps. For block-by-block encryption of variable length group, number of iterations and initial condition for the chaotic maps depend on the randomly chosen session key and encryption of previous block of plaintext, respectively. The whole process of encryption/decryption is governed by two dynamic tables, which are updated time to time during the encryption/decryption process. Simulation results show that the proposed cryptosystem requires less time to encrypt the plaintext as compared to the existing chaotic cryptosystems and further produces the ciphertext having flat distribution of same size as the plaintext.

  18. LLUVIA: A program for one-dimensional, steady-state flow through partially saturated porous media

    SciTech Connect

    Hopkins, P.L.; Eaton, R.R.

    1990-05-01

    LLUVIA is a program designed for the efficient solution of one- dimensional, steady flow through multiple layers of saturated or partially saturated, fractured, porous media. The original intent of the code was to provide initial pressure conditions to two- dimensional, finite element codes. LLUVIA's capabilities were expanded to meet the needs of analyses in the performance assessment of a proposed, high-level nuclear waste repository. The code is based on an adaptive solution method for Darcy's equation and is structured to accommodate user-defined models for hydraulic conductivity and saturation. Program structure, code input, and output are intended to facilitate the interfacing of LLUVIA with graphical and/or statistical software packages. This document describes the flow problem of interest, the solution procedure employed, and the content and content and format of all user-supplied information. A sample problem is also included. 8 refs., 13 figs.

  19. NASA One-Dimensional Combustor Simulation--User Manual for S1D_ML

    NASA Technical Reports Server (NTRS)

    Stueber, Thomas J.; Paxson, Daniel E.

    2014-01-01

    The work presented in this paper is to promote research leading to a closed-loop control system to actively suppress thermo-acoustic instabilities. To serve as a model for such a closed-loop control system, a one-dimensional combustor simulation composed using MATLAB software tools has been written. This MATLAB based process is similar to a precursor one-dimensional combustor simulation that was formatted as FORTRAN 77 source code. The previous simulation process requires modification to the FORTRAN 77 source code, compiling, and linking when creating a new combustor simulation executable file. The MATLAB based simulation does not require making changes to the source code, recompiling, or linking. Furthermore, the MATLAB based simulation can be run from script files within the MATLAB environment or with a compiled copy of the executable file running in the Command Prompt window without requiring a licensed copy of MATLAB. This report presents a general simulation overview. Details regarding how to setup and initiate a simulation are also presented. Finally, the post-processing section describes the two types of files created while running the simulation and it also includes simulation results for a default simulation included with the source code.

  20. One-Dimensional Scanning Approach to Shock Sensing

    NASA Technical Reports Server (NTRS)

    Tokars, Roger; Adamovsky, Girgory; Floyd, Bertram

    2009-01-01

    Measurement tools for high speed air flow are sought both in industry and academia. Particular interest is shown in air flows that exhibit aerodynamic shocks. Shocks are accompanied by sudden changes in density, pressure, and temperature. Optical detection and characterization of such shocks can be difficult because the medium is normally transparent air. A variety of techniques to analyze these flows are available, but they often require large windows and optical components as in the case of Schlieren measurements and/or large operating powers which precludes their use for in-flight monitoring and applications. The one-dimensional scanning approach in this work is a compact low power technique that can be used to non-intrusively detect shocks. The shock is detected by analyzing the optical pattern generated by a small diameter laser beam as it passes through the shock. The optical properties of a shock result in diffraction and spreading of the beam as well as interference fringes. To investigate the feasibility of this technique a shock is simulated by a 426 m diameter optical fiber. Analysis of results revealed a direct correlation between the optical fiber or shock location and the beam s diffraction pattern. A plot of the width of the diffraction pattern vs. optical fiber location reveals that the width of the diffraction pattern was maximized when the laser beam is directed at the center of the optical fiber. This work indicates that the one-dimensional scanning approach may be able to determine the location of an actual shock. Near and far field effects associated with a small diameter laser beam striking an optical fiber used as a simulated shock are investigated allowing a proper one-dimensional scanning beam technique.

  1. The solving of one dimensional unsteady flow with difference methods

    NASA Astrophysics Data System (ADS)

    Shao, Guangri; Shang, Yu; Wang, Rongsheng

    In this paper, one-dimensional unsteady gas flow equations are formulated with Riemann variables as the functions of time and space to be solved. By using the 'de Haller' test and a simple pipe flow with a temperature discontinuity, the equations are solved by difference methods of first-order accuracy and second-order accuracy for non-homentropic cases. As compared with the commonly used characteristic method, the results show the above-mentioned formulation and difference methods have the advantages of consuming less computer time and being easier to reach higher order accuracy. The application to turbocharged internal combustion engines is also discussed in this paper.

  2. Bloch oscillations in a one-dimensional spinor gas.

    PubMed

    Gangardt, D M; Kamenev, A

    2009-02-20

    A force applied to a spin-flipped particle in a one-dimensional spinor gas may lead to Bloch oscillations of the particle's position and velocity. The existence of Bloch oscillations crucially depends on the viscous friction force exerted by the rest of the gas on the spin excitation. We evaluate the friction in terms of the quantum fluid parameters. In particular, we show that the friction is absent for integrable cases, such as an SU(2) symmetric gas of bosons or fermions. For small deviations from the exact integrability the friction is very weak, opening the possibility to observe Bloch oscillations.

  3. Quantum Simulations of One-Dimensional Nanostructures under Arbitrary Deformations

    NASA Astrophysics Data System (ADS)

    Koskinen, Pekka

    2016-09-01

    A powerful technique is introduced for simulating mechanical and electromechanical properties of one-dimensional nanostructures under arbitrary combinations of bending, twisting, and stretching. The technique is based on an unconventional control of periodic symmetry which eliminates artifacts due to deformation constraints and quantum finite-size effects and allows transparent electronic-structure analysis. Via density-functional tight-binding implementation, the technique demonstrates its utility by predicting nonlinear electromechanical properties in carbon nanotubes and abrupt behavior in the structural yielding of Au7 and Mo6 S6 nanowires. The technique drives simulations markedly closer to the realistic modeling of these slender nanostructures under experimental conditions.

  4. Numerical computations on one-dimensional inverse scattering problems

    NASA Technical Reports Server (NTRS)

    Dunn, M. H.; Hariharan, S. I.

    1983-01-01

    An approximate method to determine the index of refraction of a dielectric obstacle is presented. For simplicity one dimensional models of electromagnetic scattering are treated. The governing equations yield a second order boundary value problem, in which the index of refraction appears as a functional parameter. The availability of reflection coefficients yield two additional boundary conditions. The index of refraction by a k-th order spline which can be written as a linear combination of B-splines is approximated. For N distinct reflection coefficients, the resulting N boundary value problems yield a system of N nonlinear equations in N unknowns which are the coefficients of the B-splines.

  5. Coherent Backscattering of Light Off One-Dimensional Atomic Strings

    NASA Astrophysics Data System (ADS)

    Sørensen, H. L.; Béguin, J.-B.; Kluge, K. W.; Iakoupov, I.; Sørensen, A. S.; Müller, J. H.; Polzik, E. S.; Appel, J.

    2016-09-01

    We present the first experimental realization of coherent Bragg scattering off a one-dimensional system—two strings of atoms strongly coupled to a single photonic mode—realized by trapping atoms in the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.

  6. Superconductivity in a one-dimensional correlated quantum system

    NASA Astrophysics Data System (ADS)

    Ding, Hanqin; Zhang, Jun

    2016-07-01

    We construct a one-dimensional (1D) theoretical model to clarify the occurrence of superconductivity. The weak-coupling (WC) theory allows a determination of the phase diagram. The constrained hopping induces additional two-body and three-body interactions. At half-filling, the three-body interaction is responsible for the triplet superconducting (TS) correlation. Away from half-filling, the two-body interaction works, favoring the singlet superconducting (SS) correlation. The results are expected to provide an insignificant insight into the superconductivity mechanism.

  7. Fourier's law for quasi-one-dimensional chaotic quantum systems

    NASA Astrophysics Data System (ADS)

    Seligman, Thomas H.; Weidenmüller, Hans A.

    2011-05-01

    We derive Fourier's law for a completely coherent quasi-one-dimensional chaotic quantum system coupled locally to two heat baths at different temperatures. We solve the master equation to first order in the temperature difference. We show that the heat conductance can be expressed as a thermodynamic equilibrium coefficient taken at some intermediate temperature. We use that expression to show that for temperatures large compared to the mean level spacing of the system, the heat conductance is inversely proportional to the level density and, thus, inversely proportional to the length of the system.

  8. Quantum quench in an atomic one-dimensional Ising chain.

    PubMed

    Meinert, F; Mark, M J; Kirilov, E; Lauber, K; Weinmann, P; Daley, A J; Nägerl, H-C

    2013-08-01

    We study nonequilibrium dynamics for an ensemble of tilted one-dimensional atomic Bose-Hubbard chains after a sudden quench to the vicinity of the transition point of the Ising paramagnetic to antiferromagnetic quantum phase transition. The quench results in coherent oscillations for the orientation of effective Ising spins, detected via oscillations in the number of doubly occupied lattice sites. We characterize the quench by varying the system parameters. We report significant modification of the tunneling rate induced by interactions and show clear evidence for collective effects in the oscillatory response. PMID:23952393

  9. One-dimensional hydrodynamic model generating a turbulent cascade.

    PubMed

    Matsumoto, Takeshi; Sakajo, Takashi

    2016-05-01

    As a minimal mathematical model generating cascade analogous to that of the Navier-Stokes turbulence in the inertial range, we propose a one-dimensional partial-differential-equation model that conserves the integral of the squared vorticity analog (enstrophy) in the inviscid case. With a large-scale random forcing and small viscosity, we find numerically that the model exhibits the enstrophy cascade, the broad energy spectrum with a sizable correction to the dimensional-analysis prediction, peculiar intermittency, and self-similarity in the dynamical system structure. PMID:27300972

  10. Dynamical Structure Factors of quasi-one-dimensional antiferromagnets

    NASA Astrophysics Data System (ADS)

    Hagemans, Rob; Caux, Jean-Sébastien; Maillet, Jean Michel

    2007-03-01

    For a long time it has been impossible to accurately calculate the dynamical structure factors (spin-spin correlators as a function of momentum and energy) of quasi-one-dimensional antiferromagnets. For integrable Heisenberg chains, the recently developed ABACUS method (a first-principles computational approach based on the Bethe Ansatz) now yields highly accurate (over 99% of the sum rule) results for the DSF for finite chains, allowing for a very precise description of neutron-scattering data over the full momentum and energy range. We show remarkable agreement between results obtained with ABACUS and experiment.

  11. Lattice-induced resonances in one-dimensional bosonic systems.

    PubMed

    von Stecher, Javier; Gurarie, Victor; Radzihovsky, Leo; Rey, Ana Maria

    2011-06-10

    We study the resonant effects produced when a Feshbach dimer crosses a scattering continuum band of atoms in an optical lattice. We numerically obtain the exact spectrum of two particles in a one-dimensional lattice and develop an effective atom-dimer Hamiltonian that accurately captures resonant effects. The lattice-induced resonances lead to the formation of bound states simultaneously above and below the scattering continuum and significantly modify the curvature of the dimer dispersion relation. The nature of the atom-dimer coupling depends strongly on the parity of the dimer state leading to a novel coupling in the case of negative parity dimers. PMID:21770514

  12. Lattice-Induced Resonances in One-Dimensional Bosonic Systems

    NASA Astrophysics Data System (ADS)

    von Stecher, Javier; Gurarie, Victor; Radzihovsky, Leo; Rey, Ana Maria

    2011-06-01

    We study the resonant effects produced when a Feshbach dimer crosses a scattering continuum band of atoms in an optical lattice. We numerically obtain the exact spectrum of two particles in a one-dimensional lattice and develop an effective atom-dimer Hamiltonian that accurately captures resonant effects. The lattice-induced resonances lead to the formation of bound states simultaneously above and below the scattering continuum and significantly modify the curvature of the dimer dispersion relation. The nature of the atom-dimer coupling depends strongly on the parity of the dimer state leading to a novel coupling in the case of negative parity dimers.

  13. Functional One-Dimensional Lipid Bilayers on Carbon Nanotube Templates

    SciTech Connect

    Artyukhin, A; Shestakov, A; Harper, J; Bakajin, O; Stroeve, P; Noy, A

    2004-07-23

    We present one-dimensional (1-D) lipid bilayer structures that integrate carbon nanotubes with a key biological environment-phospholipid membrane. Our structures consist of lipid bilayers wrapped around carbon nanotubes modified with a hydrophilic polymer cushion layer. Despite high bilayer curvature, the lipid membrane maintains its fluidity and can sustain repeated damage-recovery cycles. We also present the first evidence of spontaneous insertion of pore-forming proteins into 1-D lipid bilayers. These structures could lead to the development of new classes of biosensors and bioelectronic devices.

  14. Numerical Simulations of One-dimensional Microstructure Dynamics

    SciTech Connect

    Berezovski, M.; Berezovski, A.; Engelbrecht, J.

    2010-05-21

    Results of numerical simulations of one-dimensional wave propagation in microstructured solids are presented and compared with the corresponding results of wave propagation in given layered media. A linear microstructure model based on Mindlin theory is adopted and represented in the framework of the internal variable theory. Fully coupled systems of equations for macro-motion and microstructure evolution are rewritten in the form of conservation laws. A modification of wave propagation algorithm is used for numerical calculations. It is shown how the initial microstructure model can be improved in order to match the results obtained by both approaches.

  15. Parallel solution of sparse one-dimensional dynamic programming problems

    NASA Technical Reports Server (NTRS)

    Nicol, David M.

    1989-01-01

    Parallel computation offers the potential for quickly solving large computational problems. However, it is often a non-trivial task to effectively use parallel computers. Solution methods must sometimes be reformulated to exploit parallelism; the reformulations are often more complex than their slower serial counterparts. We illustrate these points by studying the parallelization of sparse one-dimensional dynamic programming problems, those which do not obviously admit substantial parallelization. We propose a new method for parallelizing such problems, develop analytic models which help us to identify problems which parallelize well, and compare the performance of our algorithm with existing algorithms on a multiprocessor.

  16. A Sectored-One-Dimensional Model for Simulating Combustion Instabilities in Premix Combustors

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    1999-01-01

    A one-dimensional, CFD based combustor simulation has been developed that exhibits self-excited, thermoacoustic oscillations in premixed combustor geometries that typically have large, abrupt changes in cross sectional area. The combustor geometry is approximated by dividing it into a finite number of one-dimensional sectors. Within each sector, the equations of motion are integrated numerically, along with a species transport and a reaction equation. Across the sectors, mass and energy are conserved, and momentum loss is prescribed using appropriately compatible boundary conditions that account for the area change. The resulting simulation and associated boundary conditions essentially represent a one-dimensional, multi-block technique. Details of the simulation code are presented herein. Results are then shown comparing experimentally observed and simulated operation of a particular combustor rig that exhibited different instabilities at different operating points. It will be shown that the simulation closely matched the rig data in oscillation amplitudes, frequencies, and operating points at which the instabilities occurred. Finally, advantages and limitations of the simulation technique are discussed.

  17. Silicon-based one-dimensional photonic crystal microcavity

    NASA Astrophysics Data System (ADS)

    Chen, San; Qian, Bo; Chen, Kunji; Xu, Jun; Li, Wei; Huang, Xinfan

    2004-12-01

    The layer-by-layer method is employed to prepare a-SiNx:H microcavity structure in a Plasma Enhanced Chemical Vapor Deposition (PECVD) chamber. Measurements of transmittance spectrum of as-grown samples show that the transmittance resonant peak of a cavity mode at 750 nm is introduced into the band gap of one-dimensional photonic crystal distributed Bragg reflectors based on hydrogenated amorphous silicon nitride. Also the PL measurements of a-SiNx:H microcavities are performed. There is a well agreement between the transmittance spectra and the PL of microcavity samples. In order to clarify the microcavity effects on the bulk a-SiNx:H, the PL of a λ/2-thick layer of bulk a-SiNx:H obtained under the same experimental conditions is presented. By comparison, a dramatic narrowing of emission linewidth and enhancement of PL intensity is observed. The wide emission band with 208 nm is strongly narrowed to 17 nm, and the resonant enhancement of the peak PL intensity is about two orders of magnitude with respect to the emission of the λ/2-thick layer of bulk a-SiNx:H. A linewidth of Δλ=17 nm and a quality factor of Q=50 are achieved in our one-dimensional a-SiNx photonic crystal microcavities.

  18. Transmission resonances anomaly in one-dimensional disordered quantum systems

    NASA Astrophysics Data System (ADS)

    Eisenbach, A.; Bliokh, Y.; Freilkher, V.; Kaveh, M.; Berkovits, R.

    2016-07-01

    Connections between the electronic eigenstates and conductivity of one-dimensional (1D) disordered systems is studied in the framework of the tight-binding model. We show that for weak disorder only part of the states exhibit resonant transmission and contribute to the conductivity. The rest of the eigenvalues are not associated with peaks in transmission and the amplitudes of their wave functions do not exhibit a significant maxima within the sample. Moreover, unlike ordinary states, the lifetimes of these "hidden" modes either remain constant or even decrease (depending on the coupling with the leads) as the disorder becomes stronger. In a wide range of the disorder strengths, the averaged ratio of the number of transmission peaks to the total number of the eigenstates is independent of the degree of disorder and is close to the value √{2 /5 }, which was derived analytically in the weak-scattering approximation. These results are in perfect analogy to the spectral and transport properties of light in one-dimensional randomly inhomogeneous media [Y. P. Bliokh et al., New J. Phys. 17, 113009 (2015), 10.1088/1367-2630/17/11/113009], which provides strong grounds to believe that the existence of hidden, nonconducting modes is a general phenomenon inherent to 1D open random systems, and their fraction of the total density of states is the same for quantum particles and classical waves.

  19. Dislocation-mediated melting of one-dimensional Rydberg crystals

    SciTech Connect

    Sela, Eran; Garst, Markus; Punk, Matthias

    2011-08-15

    We consider cold Rydberg atoms in a one-dimensional optical lattice in the Mott regime with a single atom per site at zero temperature. An external laser drive with Rabi frequency {Omega} and laser detuning {Delta} creates Rydberg excitations whose dynamics is governed by an effective spin-chain model with (quasi) long-range interactions. This system possesses intrinsically a large degree of frustration resulting in a ground-state phase diagram in the ({Delta},{Omega}) plane with a rich topology. As a function of {Delta}, the Rydberg blockade effect gives rise to a series of crystalline phases commensurate with the optical lattice that form a so-called devil's staircase. The Rabi frequency {Omega}, on the other hand, creates quantum fluctuations that eventually lead to a quantum melting of the crystalline states. Upon increasing {Omega}, we find that generically a commensurate-incommensurate transition to a floating Rydberg crystal that supports gapless phonon excitations occurs first. For even larger {Omega}, dislocations within the floating Rydberg crystal start to proliferate and a second, Kosterlitz-Thouless-Nelson-Halperin-Young dislocation-mediated melting transition finally destroys the crystalline arrangement of Rydberg excitations. This latter melting transition is generic for one-dimensional Rydberg crystals and persists even in the absence of an optical lattice. The floating phase and the concomitant transitions can, in principle, be detected by Bragg scattering of light.

  20. Lattice Boltzmann method for one-dimensional vector radiative transfer.

    PubMed

    Zhang, Yong; Yi, Hongliang; Tan, Heping

    2016-02-01

    A one-dimensional vector radiative transfer (VRT) model based on lattice Boltzmann method (LBM) that considers polarization using four Stokes parameters is developed. The angular space is discretized by the discrete-ordinates approach, and the spatial discretization is conducted by LBM. LBM has such attractive properties as simple calculation procedure, straightforward and efficient handing of boundary conditions, and capability of stable and accurate simulation. To validate the performance of LBM for vector radiative transfer, four various test problems are examined. The first case investigates the non-scattering thermal-emitting atmosphere with no external collimated solar. For the other three cases, the external collimated solar and three different scattering types are considered. Particularly, the LBM is extended to solve VRT in the atmospheric aerosol system where the scattering function contains singularities and the hemisphere space distributions for the Stokes vector are presented and discussed. The accuracy and computational efficiency of this algorithm are discussed. Numerical results show that the LBM is accurate, flexible and effective to solve one-dimensional polarized radiative transfer problems. PMID:26906779

  1. Generating arbitrary one-dimensional dose profiles using rotational therapy

    NASA Astrophysics Data System (ADS)

    Zhuang, Tingliang; Wu, Qiuwen

    2010-10-01

    Conformal radiation therapy can be delivered using several methods: intensity-modulated radiotherapy (IMRT) at fixed gantry angles, through the continuous gantry rotation of linac (rotational arc therapy), or by a dedicated treatment unit such as tomotherapy. The recently developed volumetric modulated arc therapy (VMAT), a form of rotational arc therapy, has attracted lots of attention from investigators to explore its capability of generating highly conformal dose to the target. The main advanced features of VMAT are the variable dose rate and gantry rotation speed. In this paper, we present a theoretical framework of generating arbitrary one-dimensional dose profiles using rotational arc therapy to further explore the new degree of freedom of the VMAT technique. This framework was applied to design a novel technique for total body irradiation (TBI) treatment, where the desired dose distribution can be simplified by a one-dimensional profile. The technique was validated using simulations and experimental measurements. The preliminary results demonstrated that the new TBI technique using either dynamic MLC only, variable dose rate only, or a combination of dynamic MLC and variable dose rate can achieve arbitrary dose distribution in one dimension, such as uniform dose to target and lower dose to critical organ. This technique does not require the use of customized compensators, nor large treatment rooms as in the conventional extended SSD technique.

  2. One-Dimensional Electrical Contact to Molybdenum Disulfide

    NASA Astrophysics Data System (ADS)

    Yang, Zheng; Ra, Changho; Ahmed, Faisal; Lee, Daeyeong; Choi, Minsup; Liu, Xiaochi; Qu, Deshun; Yoo, Won Jong; Nano Device Processing Lab Team

    Molybdenum disulfide (MoS2) is one of the promising two-dimensional materials for future application in nano electronics, which has high carrier mobility, very good stability under atmosphere, proper band gap, etc. However, its application to electronic switching devices is hindered by Fermi level pinning at metal-MoS2 interfaces. Here, we experimentally demonstrate one-dimensional electrical contact to MoS2 formed via controllable plasma etching. We fabricated Al/MoS2 FET (n-type), Mo/MoS2 FET (n-type), and Pd/MoS2 FET (ambipolar). For Mo/MoS2 FET (n-type), on/off current ratio is around 108 and mobility is around 104 cm2/(Vs). By contrast, for Pd/MoS2 FET (ambipolar), on/off current ratio is around 108, hole mobility is ranged from 350 to 650 cm2/(Vs), and the mean free path of holes at 9K is around 23 nm. All the measured mobilities are evaluated by using two-terminal field-effect configuration. We can also achieve complementary logic gates with intrinsic MoS2/metal one-dimensional electrical contact.

  3. One dimensional wavefront sensor development for tomographic flow measurements

    SciTech Connect

    Neal, D.; Pierson, R.; Chen, E.

    1995-08-01

    Optical diagnostics are extremely useful in fluid mechanics because they generally have high inherent bandwidth, and are non-intrusive. However, since optical probe measurements inherently integrate all information along the optical path, it is often difficult to isolate out-of-plane components in 3-dimensional flow events. It is also hard to make independent measurements of internal flow structure. Using an arrangement of one-dimensional wavefront sensors, we have developed a system that uses tomographic reconstruction to make two-dimensional measurements in an arbitrary flow. These measurements provide complete information in a plane normal to the flow. We have applied this system to the subsonic free jet because of the wide range of flow scales available. These measurements rely on the development of a series of one-dimensional wavefront sensors that are used to measure line-integral density variations in the flow of interest. These sensors have been constructed using linear CCD cameras and binary optics lenslet arrays. In designing these arrays, we have considered the coherent coupling between adjacent lenses and have made comparisons between theory and experimental noise measurements. The paper will present examples of the wavefront sensor development, line-integral measurements as a function of various experimental parameters, and sample tomographic reconstructions.

  4. Parafermion braid statistics in quasi-one-dimensional networks

    NASA Astrophysics Data System (ADS)

    Clarke, David; Alicea, Jason; Shtengel, Kirill

    2012-02-01

    One dimensional systems with Majorana zero modes at phase boundaries may be thought of as physical realizations of a discrete quantum wire model first put forth by Kitaev [1]. Proposed methods for braiding such Majorana fermions in one-dimensional wire networks [2] have greatly expanded the set of plausible avenues toward topological quantum computation. Recently, a generalization of the Kitaev model to parafermion modes has been developed.[3] Here, we describe the transport of such parafermion modes along the chain by the adiabatic transformation of the Hamiltonian, analogous to the transport of Majorana fermion modes. We determine the (braid) transformations of the ground state sector allowed by the adiabatic exchange of the parafermion modes in wire networks. We show that, as with Majorana fermions, none of the parafermion braid sets are universal for quantum computation. Certain parafermion chain models, unlike Majorana fermion systems, become universal with the addition of measurement operations. We discuss possible physical realizations of the parafermion models. [4pt] [1] J Alicea et al., Nature Physics 7, 412-417 (2011) [0pt] [2] A. Kitaev, arXiv:cond-mat/0010440v2 [0pt] [3] P. Fendley, unpublished

  5. A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers.

    PubMed

    de Jong, J A; Wijnant, Y H; de Boer, A

    2014-03-01

    A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic systems. The model is implementable in existing (quasi-)1D thermoacoustic codes, such as DeltaEC. Examples of generated results show good agreement with literature results. The model allows for arbitrary wave phasing; however, it is shown that the wave phasing does not significantly influence the heat transfer.

  6. Users manual for a one-dimensional Lagrangian transport model

    USGS Publications Warehouse

    Schoellhamer, D.H.; Jobson, H.E.

    1986-01-01

    A Users Manual for the Lagrangian Transport Model (LTM) is presented. The LTM uses Lagrangian calculations that are based on a reference frame moving with the river flow. The Lagrangian reference frame eliminates the need to numerically solve the convective term of the convection-diffusion equation and provides significant numerical advantages over the more commonly used Eulerian reference frame. When properly applied, the LTM can simulate riverine transport and decay processes within the accuracy required by most water quality studies. The LTM is applicable to steady or unsteady one-dimensional unidirectional flows in fixed channels with tributary and lateral inflows. Application of the LTM is relatively simple and optional capabilities improve the model 's convenience. Appendices give file formats and three example LTM applications that include the incorporation of the QUAL II water quality model 's reaction kinetics into the LTM. (Author 's abstract)

  7. Periodic transmission peak splitting in one dimensional disordered photonic structures

    NASA Astrophysics Data System (ADS)

    Kriegel, Ilka; Scotognella, Francesco

    2016-08-01

    In the present paper we present ways to modulate the periodic transmission peaks arising in disordered one dimensional photonic structures with hundreds of layers. Disordered structures in which the optical length nd (n is the refractive index and d the layer thickness) is the same for each layer show regular peaks in their transmission spectra. A proper variation of the optical length of the layers leads to a splitting of the transmission peaks. Notably, the variation of the occurrence of high and low refractive index layers, gives a tool to tune also the width of the peaks. These results are of highest interest for optical application, such as light filtering, where the manifold of parameters allows a precise design of the spectral transmission ranges.

  8. One-Dimensional Time to Explosion (Thermal Sensitivity) of ANPZ

    SciTech Connect

    Hsu, P.; Hust, G.; McClelland, M.; Gresshoff, M.

    2014-11-12

    Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 C) and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to explosion, threshold thermal explosion temperature, and determine kinetic parameters of energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. This report summarizes the recent ODTX experimental data and modeling results for 2,6-diamino-3,5-dintropyrazine (ANPZ).

  9. Negative refraction characterization in one-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Doti, R.; Lugo, J. E.; Faubert, J.

    2012-10-01

    In this work we present two experiments as evidence of negative refraction in one dimensional photonics crystals (1D PC). Particularly the porous silicon (p-Si) multilayer structure is used as 1D PC since this structure presents periodic dielectric components with specific refraction indexes and under certain conditions it can abnormally refract the light. In the first experiment we show the negative refraction for two different wavelengths, one in the visible, and the other in the infrared regions of the spectrum. In this experiment we use a fixed incidence angle for a conditioned white light beam and we look for the emerging negative refracted beam. In the second experiment we characterize de negative refraction observed for the same material by varying the incidence angle in a wide range. The obtained results are compared with a theoretic prediction according a model proposed by the authors [1]. We present a brief description of the material production and its properties, as well.

  10. Negative refraction in one-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Lugo, J. E.; Doti, Rafael; Faubert, J.

    2012-10-01

    Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here, we discuss recent theoretical and simulation results that showed that negative refraction could be present near the low frequency edge of at least the second, fourth and sixth bandgaps of a lossless one-dimensional photonic crystals (1DPC) structure. That is, negative refraction is a multiband phenomenon. We also discuss the negative refraction correctness condition that gives the angular region where negative refraction occurs. We compare two current negative refraction theoretical models with recent experimental results. In order to succeed, an output refraction correction is utilized. The correction uses Snell's law and an effective refractive index based on two effective dielectric constants. We found good agreement between experiment and both theoretical models in the negative refraction zone.

  11. A Reduced Order, One Dimensional Model of Joint Response

    SciTech Connect

    DOHNER,JEFFREY L.

    2000-11-06

    As a joint is loaded, the tangent stiffness of the joint reduces due to slip at interfaces. This stiffness reduction continues until the direction of the applied load is reversed or the total interface slips. Total interface slippage in joints is called macro-slip. For joints not undergoing macro-slip, when load reversal occurs the tangent stiffness immediately rebounds to its maximum value. This occurs due to stiction effects at the interface. Thus, for periodic loads, a softening and rebound hardening cycle is produced which defines a hysteretic, energy absorbing trajectory. For many jointed sub-structures, this hysteretic trajectory can be approximated using simple polynomial representations. This allows for complex joint substructures to be represented using simple non-linear models. In this paper a simple one dimensional model is discussed.

  12. One-dimensional Kondo lattice model at quarter filling

    NASA Astrophysics Data System (ADS)

    Xavier, J. C.; Miranda, E.

    2008-10-01

    We revisit the problem of the quarter-filled one-dimensional Kondo lattice model, for which the existence of a dimerized phase and a nonzero charge gap had been reported by Xavier [Phys. Rev. Lett. 90, 247204 (2003)]. Recently, some objections were raised claiming that the system is neither dimerized nor has a charge gap. In the interest of clarifying this important issue, we show that these objections are based on results obtained under conditions in which the dimer order is artificially suppressed. We use the incontrovertible dimerized phase of the Majumdar-Ghosh point of the J1-J2 Heisenberg model as a paradigm with which to illustrate this artificial suppression. Finally, by means of extremely accurate density-matrix renormalization-group calculations, we show that the charge gap is indeed nonzero in the dimerized phase.

  13. Localization of wave packets in one-dimensional random potentials

    NASA Astrophysics Data System (ADS)

    Valdes, Juan Pablo Ramírez; Wellens, Thomas

    2016-06-01

    We study the expansion of an initially strongly confined wave packet in a one-dimensional weak random potential with short correlation length. At long times, the expansion of the wave packet comes to a halt due to destructive interferences leading to Anderson localization. We develop an analytical description for the disorder-averaged localized density profile. For this purpose, we employ the diagrammatic method of Berezinskii which we extend to the case of wave packets, present an analytical expression of the Lyapunov exponent which is valid for small as well as for high energies, and, finally, develop a self-consistent Born approximation in order to analytically calculate the energy distribution of our wave packet. By comparison with numerical simulations, we show that our theory describes well the complete localized density profile, not only in the tails but also in the center.

  14. Novel superconducting phenomena in quasi-one-dimensional Bechgaard salts

    NASA Astrophysics Data System (ADS)

    Jerome, Denis; Yonezawa, Shingo

    2016-03-01

    It is the saturation of the transition temperature Tc in the range of 24 K for known materials in the late sixties that triggered the search for additional materials offering new coupling mechanisms leading in turn to higher Tc's. As a result of this stimulation, superconductivity in organic matter was discovered in tetramethyl-tetraselenafulvalene-hexafluorophosphate, (TMTSF)2PF6, in 1979, in the laboratory founded at Orsay by Professor Friedel and his colleagues in 1962. Although this conductor is a prototype example for low-dimensional physics, we mostly focus in this article on the superconducting phase of the ambient-pressure superconductor (TMTSF)2ClO4, which has been studied most intensively among the TMTSF salts. We shall present a series of experimental results supporting nodal d-wave symmetry for the superconducting gap in these prototypical quasi-one-dimensional conductors. xml:lang="fr"

  15. Probing the excitations of a one dimensional topological Bose insulator

    NASA Astrophysics Data System (ADS)

    Dalla Torre, Emanuele G.; Berg, Erez; Altman, Ehud

    2008-03-01

    We investigate the dynamic response of a system of ultracold dipolar atoms or molecules in the one dimensional Haldane Bose insulator phase. This phase, which was recently predicted theoretically [1], is characterized by non-local string order and its elementary excitations are domain walls in this order. We compute experimentally relevant response functions and we derive asymptotically exact expressions near the quantum critical points separating the Haldane insulator from the conventional Mott and density wave insulators. In particular, we predict a narrow absorption peak in Bragg spectroscopy experiments, due to the excitation of a single domain wall in the string order. [1] E.G. Dalla Torre, E. Berg, E. Altman, Phys. Rev Lett. 97, 260401 (2006)

  16. One-dimensional hybrid nanostructures for heterogeneous photocatalysis and photoelectrocatalysis.

    PubMed

    Xiao, Fang-Xing; Miao, Jianwei; Tao, Hua Bing; Hung, Sung-Fu; Wang, Hsin-Yi; Yang, Hong Bin; Chen, Jiazang; Chen, Rong; Liu, Bin

    2015-05-13

    Semiconductor-based photocatalysis and photoelectrocatalysis have received considerable attention as alternative approaches for solar energy harvesting and storage. The photocatalytic or photoelectrocatalytic performance of a semiconductor is closely related to the design of the semiconductor at the nanoscale. Among various nanostructures, one-dimensional (1D) nanostructured photocatalysts and photoelectrodes have attracted increasing interest owing to their unique optical, structural, and electronic advantages. In this article, a comprehensive review of the current research efforts towards the development of 1D semiconductor nanomaterials for heterogeneous photocatalysis and photoelectrocatalysis is provided and, in particular, a discussion of how to overcome the challenges for achieving full potential of 1D nanostructures is presented. It is anticipated that this review will afford enriched information on the rational exploration of the structural and electronic properties of 1D semiconductor nanostructures for achieving more efficient 1D nanostructure-based photocatalysts and photoelectrodes for high-efficiency solar energy conversion.

  17. Strongly-Refractive One-Dimensional Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z. (Inventor)

    2004-01-01

    One-dimensional (1D) photonic crystal prisms can separate a beam of polychromatic electromagnetic waves into constituent wavelength components and can utilize unconventional refraction properties for wavelength dispersion over significant portions of an entire photonic band rather than just near the band edges outside the photonic band gaps. Using a ID photonic crystal simplifies the design and fabrication process and allows the use of larger feature sizes. The prism geometry broadens the useful wavelength range, enables better optical transmission, and exhibits angular dependence on wavelength with reduced non-linearity. The properties of the 1 D photonic crystal prism can be tuned by varying design parameters such as incidence angle, exit surface angle, and layer widths. The ID photonic crystal prism can be fabricated in a planar process, and can be used as optical integrated circuit elements.

  18. Topological phase transition in quasi-one dimensional organic conductors.

    PubMed

    Ye, Xiao-Shan; Liu, Yong-Jun; Zeng, Xiang-Hua; Wu, Guoqing

    2015-01-01

    We explore topological phase transition, which involves the energy spectra of field-induced spin-density-wave (FISDW) states in quasi-one dimensional (Q1D) organic conductors, using an extended Su-Schrieffer-Heeger (SSH) model. We show that, in presence of half magnetic-flux FISDW state, the system exhibits topologically nontrivial phases, which can be characterized by a nonzero Chern number. The nontrivial evolution of the bulk bands with chemical potential in a topological phase transition is discussed. We show that the system can have a similar phase diagram which is discussed in the Haldane's model. We suggest that the topological feature should be tested experimentally in this organic system. These studies enrich the theoretical research on topologically nontrivial phases in the Q1D lattice system as compared to the Haldane topological phase appearing in the two-dimensional lattices. PMID:26612317

  19. Quasi one dimensional transport in individual electrospun composite nanofibers

    SciTech Connect

    Avnon, A. Datsyuk, V.; Trotsenko, S.; Wang, B.; Zhou, S.

    2014-01-15

    We present results of transport measurements of individual suspended electrospun nanofibers Poly(methyl methacrylate)-multiwalled carbon nanotubes. The nanofiber is comprised of highly aligned consecutive multiwalled carbon nanotubes. We have confirmed that at the range temperature from room temperature down to ∼60 K, the conductance behaves as power-law of temperature with an exponent of α ∼ 2.9−10.2. The current also behaves as power law of voltage with an exponent of β ∼ 2.3−8.6. The power-law behavior is a footprint for one dimensional transport. The possible models of this confined system are discussed. Using the model of Luttinger liquid states in series, we calculated the exponent for tunneling into the bulk of a single multiwalled carbon nanotube α{sub bulk} ∼ 0.06 which agrees with theoretical predictions.

  20. Polaron and bipolaron of uniaxially strained one dimensional zigzag ladder

    NASA Astrophysics Data System (ADS)

    Yavidov, B. Ya.

    2016-09-01

    An influence of the uniaxial strains in one dimensional zigzag ladder (1DZL) on the properties of polarons and bipolarons is considered. It is shown that strain changes all the parameters of the system, in particular, spectrum, existing bands and the masses of charge carriers. Numerical results obtained by taking into an account the Poisson effect clearly indicate that the properties of the (bi)polaronic system can be tuned via strain. Mass of bipolaron can be manipulated by the strain too which in turn leads to the way of tuning Bose-Einstein condensation temperature TBEC of bipolarons. It is shown that TBEC of bipolarons in strained 1DZL reasonably correlates with the values of critical temperature of superconductivity of certain perovskites.

  1. Nonlinear dynamics of one-dimensional supersonic Langmuir waves

    SciTech Connect

    Jungwirth, K. ); Breizman, B.N. )

    1991-08-01

    In this review specific features of dynamics of Langmuir waves in the supersonic regime are illustrated with several examples. It is shown that the limit of an adiabatic approximation considerably extends the range of analytically solvable problems. It permits one to formulate and rigorously analyze the modulational instability, as well as to explain many empirical laws deduced from numerical simulations. The formulation describes not only collapsing cavities in two and three dimensions, but predicts also the existence of compound'' solitons in a one-dimensional model. In the same model the transition from weak turbulence to the adiabatic approximation is analyzed, including phenomena of ion-sound emission by autolocalized and self-trapped plasmons. Further, the individual and collective processes of soliton formation, their mutual collisions, and their destruction by ion-sound pulses are discussed.

  2. Quantum quench dynamics in analytically solvable one-dimensional models

    NASA Astrophysics Data System (ADS)

    Iucci, Anibal; Cazalilla, Miguel A.; Giamarchi, Thierry

    2008-03-01

    In connection with experiments in cold atomic systems, we consider the non-equilibrium dynamics of some analytically solvable one-dimensional systems which undergo a quantum quench. In this quench one or several of the parameters of the Hamiltonian of an interacting quantum system are changed over a very short time scale. In particular, we concentrate on the Luttinger model and the sine-Gordon model in the Luther-Emery point. For the latter, we show that the order parameter and the two-point correlation function relax in the long time limit to the values determined by a generalized Gibbs ensemble first discussed by J. T. Jaynes [Phys. Rev. 106, 620 (1957); 108, 171 (1957)], and recently conjectured by M. Rigol et.al. [Phys. Rev. Lett. 98, 050405 (2007)] to apply to the non-equilibrium dynamics of integrable systems.

  3. Critical conductance of a one-dimensional doped Mott insulator

    NASA Astrophysics Data System (ADS)

    Garst, M.; Novikov, D. S.; Stern, Ady; Glazman, L. I.

    2008-01-01

    We consider the two-terminal conductance of a one-dimensional Mott insulator undergoing the commensurate-incommensurate quantum phase transition to a conducting state. We treat the leads as Luttinger liquids. At a specific value of compressibility of the leads, corresponding to the Luther-Emery point, the conductance can be described in terms of the free propagation of noninteracting fermions with charge e/2 . At that point, the temperature dependence of the conductance across the quantum phase transition is described by a Fermi function. The deviation from the Luther-Emery point in the leads changes the temperature dependence qualitatively. In the metallic state, the low-temperature conductance is determined by the properties of the leads, and is described by the conventional Luttinger-liquid theory. In the insulating state, conductance occurs via activation of e/2 charges, and is independent of the Luttinger-liquid compressibility.

  4. Atom-Molecule Coherence in a One-Dimensional System

    NASA Astrophysics Data System (ADS)

    Citro, R.; Orignac, E.

    2005-09-01

    We study a model of one-dimensional fermionic atoms with a narrow Feshbach resonance that allows them to bind in pairs to form bosonic molecules. We show that at low energy, a coherence develops between the molecule and fermion Luttinger liquids. At the same time, a gap opens in the spin excitation spectrum. The coherence implies that the order parameters for the molecular Bose-Einstein condensation and the atomic BCS pairing become identical. Moreover, both bosonic and fermionic charge density wave correlations decay exponentially, in contrast with a usual Luttinger liquid. We exhibit a Luther-Emery point where the systems can be described in terms of noninteracting pseudofermions. At this point we discuss the threshold behavior of density-density response functions.

  5. One-dimensional compression of sands at high pressures

    SciTech Connect

    Yamamuro, J.A.; Bopp, P.A.; Lade, P.V.

    1996-02-01

    A one-dimensional testing apparatus was developed to test soils to axial stresses up to 850 MPa. The apparatus was instrumented with strain gauges such that lateral soil stresses, and therefore K{sub 0}, could be inferred from measured circumferential strains. Three different initial densities of quartz, Cambria, and gypsum sands were tested and it was found that the effect of initial density was eliminated at high stress magnitudes. This stress magnitude was higher for mineralogically harder grains than for softer grains. The inferred values of K{sub 0} for the mineralogically harder Cambria sand was found to be constant at high pressures, but slightly below that indicates by Jaky`s equation. However, the softer gypsum sand indicated increasing values of K{sub 0} as the stress magnitude increased. This apparently was caused by inelastic, viscous flow during shearing.

  6. Pseudo-one-dimensional nucleation in dilute polymer solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Lingyun; Schmit, Jeremy D.

    2016-06-01

    Pathogenic protein fibrils have been shown in vitro to have nucleation-dependent kinetics despite the fact that one-dimensional structures do not have the size-dependent surface energy responsible for the lag time in classical theory. We present a theory showing that the conformational entropy of the peptide chains creates a free-energy barrier that is analogous to the translational entropy barrier in higher dimensions. We find that the dynamics of polymer rearrangement make it very unlikely for nucleation to succeed along the lowest free-energy trajectory, meaning that most of the nucleation flux avoids the free-energy saddle point. We use these results to construct a three-dimensional model for amyloid nucleation that accounts for conformational entropy, backbone H bonds, and side-chain interactions to compute nucleation rates as a function of concentration.

  7. Topological phase transition in quasi-one dimensional organic conductors

    NASA Astrophysics Data System (ADS)

    Ye, Xiao-Shan; Liu, Yong-Jun; Zeng, Xiang-Hua; Wu, Guoqing

    2015-11-01

    We explore topological phase transition, which involves the energy spectra of field-induced spin-density-wave (FISDW) states in quasi-one dimensional (Q1D) organic conductors, using an extended Su-Schrieffer-Heeger (SSH) model. We show that, in presence of half magnetic-flux FISDW state, the system exhibits topologically nontrivial phases, which can be characterized by a nonzero Chern number. The nontrivial evolution of the bulk bands with chemical potential in a topological phase transition is discussed. We show that the system can have a similar phase diagram which is discussed in the Haldane’s model. We suggest that the topological feature should be tested experimentally in this organic system. These studies enrich the theoretical research on topologically nontrivial phases in the Q1D lattice system as compared to the Haldane topological phase appearing in the two-dimensional lattices.

  8. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks-Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  9. Topological phase transition in quasi-one dimensional organic conductors

    PubMed Central

    Ye, Xiao-Shan; Liu, Yong-Jun; Zeng, Xiang-Hua; Wu, Guoqing

    2015-01-01

    We explore topological phase transition, which involves the energy spectra of field-induced spin-density-wave (FISDW) states in quasi-one dimensional (Q1D) organic conductors, using an extended Su-Schrieffer-Heeger (SSH) model. We show that, in presence of half magnetic-flux FISDW state, the system exhibits topologically nontrivial phases, which can be characterized by a nonzero Chern number. The nontrivial evolution of the bulk bands with chemical potential in a topological phase transition is discussed. We show that the system can have a similar phase diagram which is discussed in the Haldane’s model. We suggest that the topological feature should be tested experimentally in this organic system. These studies enrich the theoretical research on topologically nontrivial phases in the Q1D lattice system as compared to the Haldane topological phase appearing in the two-dimensional lattices. PMID:26612317

  10. Sonic black holes in a one-dimensional relativistic flow

    NASA Astrophysics Data System (ADS)

    Carbonaro, P.

    2015-09-01

    The analogy between sound propagation in a fluid background and light propagation in a curved spacetime, discovered by Unruh in 1981, does not work in general when considering the motion of a fluid which is confined in one spatial dimension being unable in (1+1) dimensions to introduce in a coherent manner an effective acoustic metric, barring some exceptional cases. In this paper a relativistic fluid is considered and the general condition for the existence of an acoustic metric in strictly one-dimensional systems is found. Attention is also paid to the physical meaning of the equations of state characterizing such systems and to the remarkable symmetry of structure taken by the basic equations. Finally the Hawking temperature is calculated in an artificial de Laval nozzle.

  11. One-dimensional optical lattices and impenetrable bosons

    SciTech Connect

    Cazalilla, M.A. |

    2003-05-01

    We study the limit of large on-site repulsion of the one-dimensional Bose-Hubbard model at low densities, and derive a strong-coupling effective Hamiltonian. By taking the lattice parameter to zero, the Hamiltonian becomes a continuum model of fermions with attractive interactions. The leading corrections to the internal energy of a hard-core-boson (Tonks) gas as well as the (finite temperature) pair correlations of a strongly interacting Bose gas are calculated. We explore the possibility of realizing, in an optical lattice, a Luttinger liquid with stronger density correlations than the Tonks gas. A quantum phase transition to a charge-density-wave Mott insulator is also discussed.

  12. Asymmetrically doped one-dimensional trans-polymers

    NASA Astrophysics Data System (ADS)

    Caldas, Heron

    2009-10-01

    More than 30 years ago [H. Shirakawa, E.J. Louis, A.G. MacDiarmid, C.K. Chiang, A.J. Heeger, J. Chem. Soc. Chem. Comm. 578 (1977); S. Etemad, A.J. Heeger, Ann. Rev. Phys. Chem. 33 (1982) 443] it was discovered that doped trans-polyacetylene (CH)x, a one-dimensional (1D) conjugated polymer, exhibits electrical conductivity. In this work we show that an asymmetrically doped 1D trans-polymer has non-conventional properties, as compared to symmetrically doped systems. Depending on the level of asymmetry between the chemical potentials of the two involved fermionic species, the polymer can be in a partially or fully spin polarized state. Some possible experimental consequences of doped 1D trans-polymers used as 1D organic polarized conductors are discussed.

  13. One-dimensional Ising model with multispin interactions

    NASA Astrophysics Data System (ADS)

    Turban, Loïc

    2016-09-01

    We study the spin-1/2 Ising chain with multispin interactions K involving the product of m successive spins, for general values of m. Using a change of spin variables the zero-field partition function of a finite chain is obtained for free and periodic boundary conditions and we calculate the two-spin correlation function. When placed in an external field H the system is shown to be self-dual. Using another change of spin variables the one-dimensional Ising model with multispin interactions in a field is mapped onto a zero-field rectangular Ising model with first-neighbour interactions K and H. The 2D system, with size m × N/m, has the topology of a cylinder with helical BC. In the thermodynamic limit N/m\\to ∞ , m\\to ∞ , a 2D critical singularity develops on the self-duality line, \\sinh 2K\\sinh 2H=1.

  14. Growth of One-Dimensional MnO2 Nanostructure

    NASA Astrophysics Data System (ADS)

    Lu, Pai; Xue, Dongfeng

    Large scale MnO2 nanorods were controllably synthesized from the inexpensive precursors (e.g., manganese acetate, ammonium persulfate) via a facile one-step low temperature hydrothermal strategy. The crystal phase and microscopic morphology of the as-prepared MnO2 nanorods were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM). Through investigating the morphology evolution of MnO2 products in the whole synthesis process, a novel growth mechanism of these MnO2 nanorods was proposed, which may be efficiently extended to other material systems as a general approach towards one-dimensional nanostructures. The obtained MnO2 nanorods may have potential applications in Li-ion batteries and supercapacitors.

  15. Magnons in one-dimensional k-component Fibonacci structures

    SciTech Connect

    Costa, C. H.; Vasconcelos, M. S.

    2014-05-07

    We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: S{sub n}{sup (k)}=S{sub n−1}{sup (k)}S{sub n−k}{sup (k)} (n≥k=0,1,2,…), where S{sub n}{sup (k)} is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.

  16. One-dimensional quantum spin heterojunction as a thermal switch

    NASA Astrophysics Data System (ADS)

    Yang, Chuan-Jing; Jin, Li-Hui; Gong, Wei-Jiang

    2016-03-01

    We study the thermal transport through a quantum spin-1 2 heterojunction, which consists of a finite-size chain with two-site anisotropic XY interaction and three-site XZX+YZY interaction coupled at its ends to two semi-infinite isotropic XY chains. By performing the Jordan-Wigner transformation, the original spin Hamiltonian is mapped onto a fermionic Hamiltonian. Then, the fermionic structure is discussed, and the heat current as a function of structural parameters is evaluated. It is found that the magnetic fields applied at respective chains play different roles in adjusting the heat current in this heterojunction. Moreover, the interplay between the anisotropy of the XY interaction and the three-site spin interaction assists to further control the thermal transport. In view of the numerical results, we propose this heterojunction to be an alternate candidate for manipulating the heat current in one-dimensional (1D) systems.

  17. Quantum rectifier in a one-dimensional photonic channel

    NASA Astrophysics Data System (ADS)

    Mascarenhas, E.; Santos, M. F.; Auffèves, A.; Gerace, D.

    2016-04-01

    By using a fully quantum approach based on an input-output formulation of the stochastic Schrödinger equation, we show rectification of radiation fields in a one-dimensional waveguide doped with a pair of ideal two-level systems for three topical cases: classical driving, under the action of noise, and single-photon pulsed excitation. We show that even under the constant action of unwanted noise the device still operates effectively as an optical isolator, which is of critical importance for noise resistance. Finally, harnessing stimulated emission allows for nonreciprocal behavior for single-photon inputs, thus showing purely quantum rectification at the single-photon level. The latter is a considerable step towards the ultimate goal of devising an unconditional quantum rectifier for arbitrary quantum states.

  18. Reprint of : Absorbing/Emitting Phonons with one dimensional MOSFETs

    NASA Astrophysics Data System (ADS)

    Bosisio, Riccardo; Gorini, Cosimo; Fleury, Geneviève; Pichard, Jean-Louis

    2016-08-01

    We consider nanowires in the field effect transistor device configuration. Modeling each nanowire as a one dimensional lattice with random site potentials, we study the heat exchanges between the nanowire electrons and the substrate phonons, when electron transport is due to phonon-assisted hops between localized states. Shifting the nanowire conduction band with a metallic gate induces different behaviors. When the Fermi potential is located near the band center, a bias voltage gives rise to small local heat exchanges which fluctuate randomly along the nanowire. When it is located near one of the band edges, the bias voltage yields heat currents which flow mainly from the substrate towards the nanowire near one boundary of the nanowire, and in the opposite direction near the other boundary. This opens interesting perspectives for heat management at submicron scales: arrays of parallel gated nanowires could be used for a field control of phonon emission/absorption.

  19. Excitations of one-dimensional supersolids with optical lattices

    NASA Astrophysics Data System (ADS)

    Hsueh, C.-H.; Tsai, Y.-C.; Wu, W. C.

    2016-06-01

    Based on mean-field Gross-Pitaevskii and Bogoliubov-de Gennes approaches, we investigate excitations of a one-dimensional soft-core interacting ultracold Bose gas under the effect of an optical lattice. It is found that no matter how deep the lattice is, at q →0 the lowest mode corresponds to a gapless phonon, ω12=v12q2 , whereas the second lowest mode corresponds to a gapped optical phonon, ω22=Δ2±v22q2 . Determination of the velocities v1,v2 , the gap Δ , and the possible sign change in ω2 upon the change of lattice depth can give decisive measures to the transitions across various supersolid and solid states. The power law v1˜(fs) 1 /2 with fs the superfluid fraction is identified in the present system at the tight-binding regime.

  20. Erosion by a one-dimensional random walk

    NASA Astrophysics Data System (ADS)

    Chisholm, Rebecca H.; Hughes, Barry D.; Landman, Kerry A.

    2014-08-01

    We consider a model introduced by Baker et al. [Phys. Rev. E 88, 042113 (2013), 10.1103/PhysRevE.88.042113] of a single lattice random walker moving on a domain of allowed sites, surrounded by blocked sites. The walker enlarges the allowed domain by eroding the boundary at its random encounters with blocked boundary sites: attempts to step onto blocked sites succeed with a given probability and convert these sites to allowed sites. The model interpolates continuously between the Pólya random walker on the one-dimensional lattice and a "blind" walker who attempts freely, but always aborts, moves to blocked sites. We obtain some exact results about the walker's location and the rate of erosion.

  1. Diffusion and ballistic transport in one-dimensional quantum systems.

    PubMed

    Sirker, J; Pereira, R G; Affleck, I

    2009-11-20

    It has been conjectured that transport in integrable one-dimensional systems is necessarily ballistic. The large diffusive response seen experimentally in nearly ideal realizations of the S=1/2 1D Heisenberg model is therefore puzzling and has not been explained so far. Here, we show that, contrary to common belief, diffusion is universally present in interacting 1D systems subject to a periodic lattice potential. We present a parameter-free formula for the spin-lattice relaxation rate which is in excellent agreement with experiment. Furthermore, we calculate the current decay directly in the thermodynamic limit using a time-dependent density matrix renormalization group algorithm and show that an anomalously large time scale exists even at high temperatures. PMID:20366058

  2. Experiment and simulation on one-dimensional plasma photonic crystals

    SciTech Connect

    Zhang, Lin; Ouyang, Ji-Ting

    2014-10-15

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5 Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range.

  3. Properties of surface modes in one dimensional plasma photonic crystals

    SciTech Connect

    Shukla, S.; Prasad, S. Singh, V.

    2015-02-15

    Properties of surface modes supported at the interface of air and a semi-infinite one dimensional plasma photonic crystal are analyzed. The surface mode equation is obtained by using transfer matrix method and applying continuity conditions of electric fields and its derivatives at the interface. It is observed that with increase in the width of cap layer, frequencies of surface modes are shifted towards lower frequency side, whereas increase in tangential component of wave-vector increases the mode frequency and total energy carried by the surface modes. With increase in plasma frequency, surface modes are found to shift towards higher frequency side. The group velocity along interface is found to control by cap layer thickness.

  4. Entanglement dynamics in one-dimensional quantum cellular automata

    SciTech Connect

    Brennen, Gavin K.; Williams, Jamie E.

    2003-10-01

    Several proposed schemes for the physical realization of a quantum computer consist of qubits arranged in a cellular array. In the quantum circuit model of quantum computation, an often complex series of two-qubit gate operations is required between arbitrarily distant pairs of lattice qubits. An alternative model of quantum computation based on quantum cellular automata (QCA) requires only homogeneous local interactions that can be implemented in parallel. This would be a huge simplification in an actual experiment. We find some minimal physical requirements for the construction of unitary QCA in a one-dimensional Ising spin chain and demonstrate optimal pulse sequences for information transport and entanglement distribution. We also introduce the theory of nonunitary QCA and show by example that nonunitary rules can generate environment assisted entanglement.

  5. Pseudo-one-dimensional nucleation in dilute polymer solutions.

    PubMed

    Zhang, Lingyun; Schmit, Jeremy D

    2016-06-01

    Pathogenic protein fibrils have been shown in vitro to have nucleation-dependent kinetics despite the fact that one-dimensional structures do not have the size-dependent surface energy responsible for the lag time in classical theory. We present a theory showing that the conformational entropy of the peptide chains creates a free-energy barrier that is analogous to the translational entropy barrier in higher dimensions. We find that the dynamics of polymer rearrangement make it very unlikely for nucleation to succeed along the lowest free-energy trajectory, meaning that most of the nucleation flux avoids the free-energy saddle point. We use these results to construct a three-dimensional model for amyloid nucleation that accounts for conformational entropy, backbone H bonds, and side-chain interactions to compute nucleation rates as a function of concentration. PMID:27415194

  6. Switching synchronization in one-dimensional memristive networks

    NASA Astrophysics Data System (ADS)

    Slipko, Valeriy A.; Shumovskyi, Mykola; Pershin, Yuriy V.

    2015-11-01

    We report on a switching synchronization phenomenon in one-dimensional memristive networks, which occurs when several memristive systems with different switching constants are switched from the high- to low-resistance state. Our numerical simulations show that such a collective behavior is especially pronounced when the applied voltage slightly exceeds the combined threshold voltage of memristive systems. Moreover, a finite increase in the network switching time is found compared to the average switching time of individual systems. An analytical model is presented to explain our observations. Using this model, we have derived asymptotic expressions for memory resistances at short and long times, which are in excellent agreement with results of our numerical simulations.

  7. Equilibrium properties of a one-dimensional kinetic system.

    NASA Technical Reports Server (NTRS)

    Williams, J. H.; Joyce, G.

    1973-01-01

    One-dimensional systems of N = 500 and 250 particles in equilibrium are numerically simulated utilizing the method of molecular dynamics. Periodic boundary conditions are imposed. The classical two-body interaction potential is short range, repulsive and has a corresponding finite force. The equations of state are determined for densities both less and greater than one. Corresponding theoretical isochores are determined from models based on nearest-neighbor interactions and on a truncated virial expansion, and a comparison is made with the experimental isochores. Time independent radial distributions are constructed numerically and discussed. A change of state from a solidlike state to a fluid-gas state based on the penetrability of the particles is predicted. The transition temperatures are estimated from the radial distribution functions and the nearest-neighbor model. Self-diffusion is observed and the corresponding constants are determined from the velocity autocorrelation functions.

  8. Efficient algorithm for approximating one-dimensional ground states

    SciTech Connect

    Aharonov, Dorit; Arad, Itai; Irani, Sandy

    2010-07-15

    The density-matrix renormalization-group method is very effective at finding ground states of one-dimensional (1D) quantum systems in practice, but it is a heuristic method, and there is no known proof for when it works. In this article we describe an efficient classical algorithm which provably finds a good approximation of the ground state of 1D systems under well-defined conditions. More precisely, our algorithm finds a matrix product state of bond dimension D whose energy approximates the minimal energy such states can achieve. The running time is exponential in D, and so the algorithm can be considered tractable even for D, which is logarithmic in the size of the chain. The result also implies trivially that the ground state of any local commuting Hamiltonian in 1D can be approximated efficiently; we improve this to an exact algorithm.

  9. One-dimensional quantum walk with unitary noise

    SciTech Connect

    Shapira, Daniel; Biham, Ofer; Bracken, A.J.; Hackett, Michelle

    2003-12-01

    The effect of unitary noise on the discrete one-dimensional quantum walk is studied using computer simulations. For the noiseless quantum walk, starting at the origin (n=0) at time t=0, the position distribution P{sub t}(n) at time t is very different from the Gaussian distribution obtained for the classical random walk. Furthermore, its standard deviation, {sigma}(t) scales as {sigma}(t){approx}t, unlike the classical random walk for which {sigma}(t){approx}{radical}(t). It is shown that when the quantum walk is exposed to unitary noise, it exhibits a crossover from quantum behavior for short times to classical-like behavior for long times. The crossover time is found to be T{approx}{alpha}{sup -2}, where {alpha} is the standard deviation of the noise.

  10. Majorana fermion exchange in strictly one-dimensional structures

    NASA Astrophysics Data System (ADS)

    Chiu, Ching-Kai; Vazifeh, M. M.; Franz, M.

    2015-04-01

    It is generally thought that the adiabatic exchange of two identical particles is impossible in one spatial dimension. Here we describe a simple protocol that permits the adiabatic exchange of two Majorana fermions in a one-dimensional topological superconductor wire. The exchange relies on the concept of “Majorana shuttle” whereby a π domain wall in the superconducting order parameter which hosts a pair of ancillary majoranas delivers one zero mode across the wire while the other one tunnels in the opposite direction. The method requires some tuning of parameters and does not, therefore, enjoy full topological protection. The resulting exchange statistics, however, remain non-Abelian for a wide range of parameters that characterize the exchange.

  11. One-dimensional cloud fluid model for propagating star formation

    NASA Technical Reports Server (NTRS)

    Titus, Timothy N.; Struck-Marcell, Curtis

    1990-01-01

    The aim of this project was to study the propagation of star formation (SF) with a self-consistent deterministic model for the interstellar gas. The questions of under what conditions does star formation propagate in this model and what are the mechanisms of the propagation are explored. Here, researchers used the deterministic Oort-type cloud fluid model of Scalo and Struck-Marcell (1984, also see the review of Struck-Marcell, Scalo and Appleton 1987). This cloud fluid approach includes simple models for the effects of cloud collisional coalescence or disruption, collisional energy dissipation, and cloud disruption and acceleration as the result of young star winds, HII regions and supernovae. An extensive one-zone parameter study is presented in Struck-Marcell and Scalo (1987). To answer the questions above, researchers carried out one-dimensional calculations for an annulus within a galactic disk, like the so-called solar neighborhood of the galactic chemical evolution. In the calculations the left-hand boundary is set equal to the right hand boundary. The calculation is obviously idealized; however, it is computationally convenient to study the first order effects of propagating star formation. The annulus was treated as if it were at rest, i.e., in the local rotating frame. This assumption may remove some interesting effects of a supersonic gas flow, but was necessary to maintain a numerical stability in the annulus. The results on the one-dimensional propagation of SF in the Oort cloud fluid model follow: (1) SF is propagated by means of hydrodynamic waves, which can be generated by external forces or by the pressure generated by local bursts. SF is not effectively propagated via diffusion or variation in cloud interaction rates without corresponding density and velocity changes. (2) The propagation and long-range effects of SF depend on how close the gas density is to the critical threshold value, i.e., on the susceptibility of the medium.

  12. Magnetic properties of manganese based one-dimensional spin chains.

    PubMed

    Asha, K S; Ranjith, K M; Yogi, Arvind; Nath, R; Mandal, Sukhendu

    2015-12-14

    We have correlated the structure-property relationship of three manganese-based inorganic-organic hybrid structures. Compound 1, [Mn2(OH-BDC)2(DMF)3] (where BDC = 1,4-benzene dicarboxylic acid and DMF = N,N'-dimethylformamide), contains Mn2O11 dimers as secondary building units (SBUs), which are connected by carboxylate anions forming Mn-O-C-O-Mn chains. Compound 2, [Mn2(BDC)2(DMF)2], contains Mn4O20 clusters as SBUs, which also form Mn-O-C-O-Mn chains. In compound 3, [Mn3(BDC)3(DEF)2] (where DEF = N,N'-diethylformamide), the distorted MnO6 octahedra are linked to form a one-dimensional chain with Mn-O-Mn connectivity. The magnetic properties were investigated by means of magnetization and heat capacity measurements. The temperature dependent magnetic susceptibility of all the three compounds could be nicely fitted using a one-dimensional S = 5/2 Heisenberg antiferromagnetic chain model and the value of intra-chain exchange coupling (J/k(B)) between Mn(2+) ions was estimated to be ∼1.1 K, ∼0.7 K, and ∼0.46 K for compounds 1, 2, and 3, respectively. Compound 1 does not undergo any magnetic long-range-order down to 2 K while compounds 2 and 3 undergo long-range magnetic order at T(N) ≈ 4.2 K and ≈4.3 K, respectively, which are of spin-glass type. From the values of J/k(B) and T(N) the inter-chain coupling (J(⊥)/k(B)) was calculated to be about 0.1J/k(B) for both compounds 2 and 3, respectively.

  13. Magnetic properties of manganese based one-dimensional spin chains.

    PubMed

    Asha, K S; Ranjith, K M; Yogi, Arvind; Nath, R; Mandal, Sukhendu

    2015-12-14

    We have correlated the structure-property relationship of three manganese-based inorganic-organic hybrid structures. Compound 1, [Mn2(OH-BDC)2(DMF)3] (where BDC = 1,4-benzene dicarboxylic acid and DMF = N,N'-dimethylformamide), contains Mn2O11 dimers as secondary building units (SBUs), which are connected by carboxylate anions forming Mn-O-C-O-Mn chains. Compound 2, [Mn2(BDC)2(DMF)2], contains Mn4O20 clusters as SBUs, which also form Mn-O-C-O-Mn chains. In compound 3, [Mn3(BDC)3(DEF)2] (where DEF = N,N'-diethylformamide), the distorted MnO6 octahedra are linked to form a one-dimensional chain with Mn-O-Mn connectivity. The magnetic properties were investigated by means of magnetization and heat capacity measurements. The temperature dependent magnetic susceptibility of all the three compounds could be nicely fitted using a one-dimensional S = 5/2 Heisenberg antiferromagnetic chain model and the value of intra-chain exchange coupling (J/k(B)) between Mn(2+) ions was estimated to be ∼1.1 K, ∼0.7 K, and ∼0.46 K for compounds 1, 2, and 3, respectively. Compound 1 does not undergo any magnetic long-range-order down to 2 K while compounds 2 and 3 undergo long-range magnetic order at T(N) ≈ 4.2 K and ≈4.3 K, respectively, which are of spin-glass type. From the values of J/k(B) and T(N) the inter-chain coupling (J(⊥)/k(B)) was calculated to be about 0.1J/k(B) for both compounds 2 and 3, respectively. PMID:26455515

  14. Bjorken flow in one-dimensional relativistic magnetohydrodynamics with magnetization

    NASA Astrophysics Data System (ADS)

    Pu, Shi; Roy, Victor; Rezzolla, Luciano; Rischke, Dirk H.

    2016-04-01

    We study the one-dimensional, longitudinally boost-invariant motion of an ideal fluid with infinite conductivity in the presence of a transverse magnetic field, i.e., in the ideal transverse magnetohydrodynamical limit. In an extension of our previous work Roy et al., [Phys. Lett. B 750, 45 (2015)], we consider the fluid to have a nonzero magnetization. First, we assume a constant magnetic susceptibility χm and consider an ultrarelativistic ideal gas equation of state. For a paramagnetic fluid (i.e., with χm>0 ), the decay of the energy density slows down since the fluid gains energy from the magnetic field. For a diamagnetic fluid (i.e., with χm<0 ), the energy density decays faster because it feeds energy into the magnetic field. Furthermore, when the magnetic field is taken to be external and to decay in proper time τ with a power law ˜τ-a, two distinct solutions can be found depending on the values of a and χm. Finally, we also solve the ideal magnetohydrodynamical equations for one-dimensional Bjorken flow with a temperature-dependent magnetic susceptibility and a realistic equation of state given by lattice-QCD data. We find that the temperature and energy density decay more slowly because of the nonvanishing magnetization. For values of the magnetic field typical for heavy-ion collisions, this effect is, however, rather small. It is only for magnetic fields about an order of magnitude larger than expected for heavy-ion collisions that the system is substantially reheated and the lifetime of the quark phase might be extended.

  15. Source Distribution Method for Unsteady One-Dimensional Flows With Small Mass, Momentum, and Heat Addition and Small Area Variation

    NASA Technical Reports Server (NTRS)

    Mirels, Harold

    1959-01-01

    A source distribution method is presented for obtaining flow perturbations due to small unsteady area variations, mass, momentum, and heat additions in a basic uniform (or piecewise uniform) one-dimensional flow. First, the perturbations due to an elemental area variation, mass, momentum, and heat addition are found. The general solution is then represented by a spatial and temporal distribution of these elemental (source) solutions. Emphasis is placed on discussing the physical nature of the flow phenomena. The method is illustrated by several examples. These include the determination of perturbations in basic flows consisting of (1) a shock propagating through a nonuniform tube, (2) a constant-velocity piston driving a shock, (3) ideal shock-tube flows, and (4) deflagrations initiated at a closed end. The method is particularly applicable for finding the perturbations due to relatively thin wall boundary layers.

  16. Investigation of fast ion behavior using orbit following Monte-Carlo code in magnetic perturbed field in KSTAR

    NASA Astrophysics Data System (ADS)

    Shinohara, Kouji; Suzuki, Yasuhiro; Kim, Junghee; Kim, Jun Young; Jeon, Young Mu; Bierwage, Andreas; Rhee, Tongnyeol

    2016-11-01

    The fast ion dynamics and the associated heat load on the plasma facing components in the KSTAR tokamak were investigated with the orbit following Monte-Carlo (OFMC) code in several magnetic field configurations and realistic wall geometry. In particular, attention was paid to the effect of resonant magnetic perturbation (RMP) fields. Both the vacuum field approximation as well as the self-consistent field that includes the response of a stationary plasma were considered. In both cases, the magnetic perturbation (MP) is dominated by the toroidal mode number n  =  1, but otherwise its structure is strongly affected by the plasma response. The loss of fast ions increased significantly when the MP field was applied. Most loss particles hit the poloidal limiter structure around the outer mid-plane on the low field side, but the distribution of heat loads across the three limiters varied with the form of the MP. Short-timescale loss of supposedly well-confined co-passing fast ions was also observed. These losses started within a few poloidal transits after the fast ion was born deep inside the plasma on the high-field side of the magnetic axis. In the configuration studied, these losses are facilitated by the combination of two factors: (i) the large magnetic drift of fast ions across a wide range of magnetic surfaces due to a low plasma current, and (ii) resonant interactions between the fast ions and magnetic islands that were induced inside the plasma by the external RMP field. These effects are expected to play an important role in present-day tokamaks.

  17. Symmetry-broken local-density approximation for one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Rogers, Fergus J. M.; Ball, Caleb J.; Loos, Pierre-François

    2016-06-01

    Within density-functional theory, the local-density approximation (LDA) correlation functional is typically built by fitting the difference between the near-exact and Hartree-Fock (HF) energies of the uniform electron gas (UEG), together with analytic perturbative results from the high- and low-density regimes. Near-exact energies are obtained by performing accurate diffusion Monte Carlo calculations, while HF energies are usually assumed to be the Fermi fluid HF energy. However, it has been known since the seminal work of A. W. Overhauser [Phys. Rev. Lett. 3, 414 (1959), 10.1103/PhysRevLett.3.414; Phys. Rev. 128, 1437 (1962), 10.1103/PhysRev.128.1437] that one can obtain lower, symmetry-broken (SB) HF energies at any density. Here, we have computed the SBHF energies of the one-dimensional UEG and constructed a SB version of the LDA (SBLDA) from the results. We compare the performance of the LDA and SBLDA functionals when applied to one-dimensional systems, including atoms and molecules. Generalization to higher dimensions is also discussed.

  18. Mechanism of spin and charge separation in one-dimensional quantum antiferromagnets

    SciTech Connect

    Mudry, C.; Fradkin, E. )

    1994-10-15

    We reconsider the problem of separation of spin and charge in one-dimensional quantum antiferromagnets. We show that spin and charge separation in one-dimensional strongly correlated systems cannot be described by the slave-boson or fermion representation within any perturbative treatment of the interactions between the slave holons and slave spinons. The constraint of single occupancy must be implemented exactly. As a result the slave fermions and bosons are not part of the physical spectrum. Instead, the excitations that carry the separate spin and charge quantum numbers are solitons. To prove this result, it is sufficient to study the pure spinon sector in the slave-boson representation. We start with a short-range resonating-valence-bond state spin liquid mean-field theory for the frustrated antiferromagnetic spin-1/2 chain. We derive an effective theory for the fluctuations of the Affleck-Marston and Anderson order parameters. We show how to recover the phase diagram as a function of the frustration by treating the fluctuations nonperturbatively.

  19. Fermi surface study of quasi-one-dimensional metals using magneto-optical techniques

    NASA Astrophysics Data System (ADS)

    Oshima, Y.; Kimata, M.; Kishigi, K.; Ohta, H.; Koyama, K.; Motokawa, M.; Nishikawa, H.; Kikuchi, K.; Ikemoto, I.

    2003-08-01

    Magneto-optical measurements of a quasi-one-dimensional (q1D) organic superconductor (DMET)2I3 have been performed by using a cavity perturbation technique. Several resonant absorption lines, which can be attributed to the q1D periodic orbit resonance (q1D POR), were observed as well as quite unusual high order q1D PORs coming from its corrugated Fermi surface (FS) in the interlayer direction. Moreover, these resonances seem to disappear when the magnetic field is applied close to the conducting axis due to the FS topological effect, and the transfer integral ratio can be obtained from the angular dependence of q1D POR. The FS of (DMET)2I3 can be estimated from these analyses of q1D PORs, and we will show that it has a characteristic FS structure. The observed results also indicate that the interlayer transport of (DMET)2I3 is coherent.

  20. Anomalous Bloch oscillations in one-dimensional parity-breaking periodic potentials

    SciTech Connect

    Pettini, Giulio; Modugno, Michele

    2011-01-15

    We investigate the dynamics of a wave packet in a parity-breaking one-dimensional periodic potential slowly varied in time and perturbed by a linear potential. Parity is broken by considering an asymmetric double well per unit cell. By comparing the prediction of the semiclassical dynamics with the full Schroedinger solution, we show that Bloch oscillations are strongly affected by anomalous velocity corrections related to Berry's phase. We characterize how these effects depend on the degree of parity breaking of the potential and on the modulation parameters. We also discuss how to measure the effects of the anomalous velocity in current experiments with noninteracting Bose-Einstein condensates in bichromatic optical lattices, under the effect of gravity.

  1. Decay of density waves in coupled one-dimensional many-body-localized systems

    NASA Astrophysics Data System (ADS)

    Prelovšek, Peter

    2016-10-01

    This work analyzes the behavior of coupled disordered one-dimensional systems as modelled by identical fermionic Hubbard chains with the on-site potential disorder and coupling emerging through the interchain hopping t'. The study is motivated by the experiment on fermionic cold atoms on a disordered lattice, where a decay rate of the quenched density wave was measured. We present a derivation of the decay rate Γ within perturbation theory and show that, even at large disorder along the chains, the interaction leads to finite Γ >0 , the mechanism being the interaction-induced coupling of in-chain localized and interchain extended single-fermion states. Explicit expressions for Γ are presented for a weak interaction U U >t' . It is shown that, in both regimes, Γ increases with the interchain hopping t', as well as decreases with increasing disorder.

  2. Boundary-induced dynamics in one-dimensional topological systems and memory effects of edge modes

    NASA Astrophysics Data System (ADS)

    He, Yan; Chien, Chih-Chun

    2016-07-01

    Dynamics induced by a change of boundary conditions reveals rate-dependent signatures associated with topological properties in one-dimensional Kitaev chain and SSH model. While the perturbation from a change of the boundary propagates into the bulk, the density of topological edge modes in the case of transforming to open boundary condition reaches steady states. The steady-state density depends on the transformation rate of the boundary and serves as an illustration of quantum memory effects in topological systems. Moreover, while a link is physically broken as the boundary condition changes, some correlation functions can remain finite across the broken link and keep a record of the initial condition. By testing those phenomena in the nontopological regimes of the two models, none of the interesting signatures of memory effects can be observed. Our results thus contrast the importance of topological properties in boundary-induced dynamics.

  3. A new method to calculate Berry phase in one-dimensional quantum anomalous Hall insulator

    NASA Astrophysics Data System (ADS)

    Liao, Yi

    2016-08-01

    Based on the residue theorem and degenerate perturbation theory, we derive a new, simple and general formula for Berry phase calculation in a two-level system for which the Hamiltonian is a real symmetric matrix. The special torus topology possessed by the first Brillouin zone (1 BZ) of this kind of systems ensures the existence of a nonzero Berry phase. We verify the correctness of our formula on the Su-Schrieffer-Heeger (SSH) model. Then the Berry phase of one-dimensional quantum anomalous Hall insulator (1DQAHI) is calculated analytically by applying our method, the result being -π/2 -π/4 sgn (B) [ sgn (Δ - 4 B) + sgn (Δ) ]. Finally, illuminated by this idea, we investigate the Chern number in the two-dimensional case, and find a very simple way to determine the parameter range of the non-trivial Chern number in the phase diagram.

  4. An adaptive grid algorithm for one-dimensional nonlinear equations

    NASA Technical Reports Server (NTRS)

    Gutierrez, William E.; Hills, Richard G.

    1990-01-01

    Richards' equation, which models the flow of liquid through unsaturated porous media, is highly nonlinear and difficult to solve. Step gradients in the field variables require the use of fine grids and small time step sizes. The numerical instabilities caused by the nonlinearities often require the use of iterative methods such as Picard or Newton interation. These difficulties result in large CPU requirements in solving Richards equation. With this in mind, adaptive and multigrid methods are investigated for use with nonlinear equations such as Richards' equation. Attention is focused on one-dimensional transient problems. To investigate the use of multigrid and adaptive grid methods, a series of problems are studied. First, a multigrid program is developed and used to solve an ordinary differential equation, demonstrating the efficiency with which low and high frequency errors are smoothed out. The multigrid algorithm and an adaptive grid algorithm is used to solve one-dimensional transient partial differential equations, such as the diffusive and convective-diffusion equations. The performance of these programs are compared to that of the Gauss-Seidel and tridiagonal methods. The adaptive and multigrid schemes outperformed the Gauss-Seidel algorithm, but were not as fast as the tridiagonal method. The adaptive grid scheme solved the problems slightly faster than the multigrid method. To solve nonlinear problems, Picard iterations are introduced into the adaptive grid and tridiagonal methods. Burgers' equation is used as a test problem for the two algorithms. Both methods obtain solutions of comparable accuracy for similar time increments. For the Burgers' equation, the adaptive grid method finds the solution approximately three times faster than the tridiagonal method. Finally, both schemes are used to solve the water content formulation of the Richards' equation. For this problem, the adaptive grid method obtains a more accurate solution in fewer work units and

  5. A Smart Colorful Supercapacitor with One Dimensional Photonic Crystals.

    PubMed

    Liu, Cihui; Liu, Xing; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin

    2015-01-01

    To meet the pressing demands for portable and flexible equipment in contemporary society, developing flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and ease of strongly required. However, estimating the state-of-charge of existing supercapacitors is difficult, and thus their service life is limited. In this study, we fabricate a flexible color indicative supercapacitor device with mesoporous polyaniline (mPANI)/Poly(N-Isopropyl acrylamide-Graphene Oxide-Acrylic Acid) (P(NiPPAm-GO-AA)) one dimensional photonic crystals (1DPCs) as the electrode material through a low-cost, eco-friendly, and scalable fabrication process. We found that the state-of-charge could be monitored by the structural color oscillation due to the change in the photonic band gap position of the 1DPCs. The flexible 1DPCs supercapacitor is thin at 3 mm and exhibits good specific capacitance of 22.6 F g(-1) with retention of 91.1% after 3,000 cycles. This study shows the application of the 1DPCs supercapacitor as a visual ultrathin power source. The technology may find many applications in future wearable electronics. PMID:26689375

  6. Dynamic response of one-dimensional bosons in a trap

    SciTech Connect

    Golovach, Vitaly N.; Minguzzi, Anna; Glazman, Leonid I.

    2009-10-15

    We calculate the dynamic structure factor S(q,{omega}) of a one-dimensional (1D) interacting Bose gas confined in a harmonic trap. The effective interaction depends on the strength of the confinement enforcing the (1D) motion of atoms; interaction may be further enhanced by superimposing an optical lattice on the trap potential. In the compressible state, we find that the smooth variation in the gas density around the trap center leads to softening of the singular behavior of S(q,{omega}) at the first Lieb excitation mode compared to the behavior predicted for homogeneous 1D systems. Nevertheless, the density-averaged response S(q,{omega}) remains a nonanalytic function of q and {omega} at the first Lieb excitation mode in the limit of weak trap confinement. The exponent of the power-law nonanalyticity is modified due to the inhomogeneity in a universal way and thus bears unambiguously the information about the (homogeneous) Lieb-Liniger model. A strong optical lattice causes formation of Mott phases. Deep in the Mott regime, we predict a semicircular peak in S(q,{omega}) centered at the on-site repulsion energy, {omega}=U. Similar peaks of smaller amplitudes exist at multiples of U as well. We explain the suppression of the dynamic response with entering into the Mott regime, observed recently by Clement et al. [Phys. Rev. Lett. 102, 155301 (2009)], based on an f-sum rule for the Bose-Hubbard model.

  7. Thermal transport in disordered one-dimensional spin chains

    NASA Astrophysics Data System (ADS)

    Poboiko, Igor; Feigel'man, Mikhail

    2015-12-01

    We study a one-dimensional anisotropic XXZ Heisenberg spin-1/2 chain with weak random fields hizSiz by means of Jordan-Wigner transformation to spinless Luttinger liquid with disorder and bosonization technique. First, we reinvestigate the phase diagram of the system in terms of dimensionless disorder γ =

    /J2≪1 and anisotropy parameter Δ =Jz/Jx y , we find the range of these parameters where disorder is irrelevant in the infrared limit and spin-spin correlations are described by power laws, and compare it with previously obtained numerical and analytical results. Then we use the diagram technique in terms of plasmon excitations to study the low-temperature (T ≪J ) behavior of heat conductivity κ and spin conductivity σ in this power-law phase. The obtained Lorentz number L ≡κ /σ T differs from the value derived earlier by means of the memory function method. We argue also that in the studied region inelastic scattering is strong enough to suppress quantum interference in the low-temperature limit.

  8. Digital noise generators using one-dimensional chaotic maps

    SciTech Connect

    Martínez-Ñonthe, J. A; Palacios-Luengas, L.; Cruz-Irisson, M.; Vazquez Medina, R.; Díaz Méndez, J. A.

    2014-05-15

    This work shows how to improve the statistical distribution of signals produced by digital noise generators designed with one-dimensional (1-D) chaotic maps. It also shows that in a digital electronic design the piecewise linear chaotic maps (PWLCM) should be considered because they do not have stability islands in its chaotic behavior region, as it occurs in the case of the logistic map, which is commonly used to build noise generators. The design and implementation problems of the digital noise generators are analyzed and a solution is proposed. This solution relates the output of PWLCM, usually defined in the real numbers' domain, with a codebook of S elements, previously defined. The proposed solution scheme produces digital noise signals with a statistical distribution close to a uniform distribution. Finally, this work shows that it is possible to have control over the statistical distribution of the noise signal by selecting the control parameter of the PWLCM and using, as a design criterion, the bifurcation diagram.

  9. Characterization of Thermal Transport in One-dimensional Solid Materials.

    PubMed

    Liu, Guoqing; Lin, Huan; Tang, Xiaoduan; Bergler, Kevin; Wang, Xinwei

    2014-01-01

    The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (ρcp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses. PMID:24514072

  10. Characterization of Thermal Transport in One-dimensional Solid Materials

    PubMed Central

    Liu, Guoqing; Lin, Huan; Tang, Xiaoduan; Bergler, Kevin; Wang, Xinwei

    2014-01-01

    The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (ρcp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses. PMID:24514072

  11. Topological water wave states in a one-dimensional structure

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoju; Gao, Fei; Zhang, Baile

    2016-07-01

    Topological concepts have been introduced into electronic, photonic, and phononic systems, but have not been studied in surface-water-wave systems. Here we study a one-dimensional periodic resonant surface-water-wave system and demonstrate its topological transition. By selecting three different water depths, we can construct different types of water waves - shallow, intermediate and deep water waves. The periodic surface-water-wave system consists of an array of cylindrical water tanks connected with narrow water channels. As the width of connecting channel varies, the band diagram undergoes a topological transition which can be further characterized by Zak phase. This topological transition holds true for shallow, intermediate and deep water waves. However, the interface state at the boundary separating two topologically distinct arrays of water tanks can exhibit different bands for shallow, intermediate and deep water waves. Our work studies for the first time topological properties of water wave systems, and paves the way to potential management of water waves.

  12. Charge transport through one-dimensional Moiré crystals.

    PubMed

    Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Della Rocca, Maria Luisa; Lafarge, Philippe; Charlier, Jean-Christophe

    2016-01-01

    Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations. PMID:26786067

  13. Automated quantification of one-dimensional nanostructure alignment on surfaces

    NASA Astrophysics Data System (ADS)

    Dong, Jianjin; Goldthorpe, Irene A.; Mohieddin Abukhdeir, Nasser

    2016-06-01

    A method for automated quantification of the alignment of one-dimensional (1D) nanostructures from microscopy imaging is presented. Nanostructure alignment metrics are formulated and shown to be able to rigorously quantify the orientational order of nanostructures within a two-dimensional domain (surface). A complementary image processing method is also presented which enables robust processing of microscopy images where overlapping nanostructures might be present. Scanning electron microscopy (SEM) images of nanowire-covered surfaces are analyzed using the presented methods and it is shown that past single parameter alignment metrics are insufficient for highly aligned domains. Through the use of multiple parameter alignment metrics, automated quantitative analysis of SEM images is shown to be possible and the alignment characteristics of different samples are able to be quantitatively compared using a similarity metric. The results of this work provide researchers in nanoscience and nanotechnology with a rigorous method for the determination of structure/property relationships, where alignment of 1D nanostructures is significant.

  14. Validation and Comparison of One-Dimensional Graound Motion Methodologies

    SciTech Connect

    B. Darragh; W. Silva; N. Gregor

    2006-06-28

    Both point- and finite-source stochastic one-dimensional ground motion models, coupled to vertically propagating equivalent-linear shear-wave site response models are validated using an extensive set of strong motion data as part of the Yucca Mountain Project. The validation and comparison exercises are presented entirely in terms of 5% damped pseudo absolute response spectra. The study consists of a quantitative analyses involving modeling nineteen well-recorded earthquakes, M 5.6 to 7.4 at over 600 sites. The sites range in distance from about 1 to about 200 km in the western US (460 km for central-eastern US). In general, this validation demonstrates that the stochastic point- and finite-source models produce accurate predictions of strong ground motions over the range of 0 to 100 km and for magnitudes M 5.0 to 7.4. The stochastic finite-source model appears to be broadband, producing near zero bias from about 0.3 Hz (low frequency limit of the analyses) to the high frequency limit of the data (100 and 25 Hz for response and Fourier amplitude spectra, respectively).

  15. Solitary Wave in One-dimensional Buckyball System at Nanoscale

    PubMed Central

    Xu, Jun; Zheng, Bowen; Liu, Yilun

    2016-01-01

    We have studied the stress wave propagation in one-dimensional (1-D) nanoscopic buckyball (C60) system by molecular dynamics (MD) simulation and quantitative modeling. Simulation results have shown that solitary waves are generated and propagating in the buckyball system through impacting one buckyball at one end of the buckyball chain. We have found the solitary wave behaviors are closely dependent on the initial temperature and impacting speed of the buckyball chain. There are almost no dispersion and dissipation of the solitary waves (stationary solitary wave) for relatively low temperature and high impacting speed. While for relatively high temperature and low impacting speed the profile of the solitary waves is highly distorted and dissipated after propagating several tens of buckyballs. A phase diagram is proposed to describe the effect of the temperature and impacting speed on the solitary wave behaviors in buckyball system. In order to quantitatively describe the wave behavior in buckyball system, a simple nonlinear-spring model is established, which can describe the MD simulation results at low temperature very well. The results presented in this work may lay a solid step towards the further understanding and manipulation of stress wave propagation and impact energy mitigation at nanoscale. PMID:26891624

  16. Interspecies tunneling in one-dimensional Bose mixtures

    SciTech Connect

    Pflanzer, Anika C.; Zoellner, Sascha; Schmelcher, Peter

    2010-02-15

    We study the ground-state properties and quantum dynamics of few-boson mixtures with strong interspecies repulsion in one-dimensional traps. If one species localizes at the center, e.g., due to a very large mass compared to the other component, it represents an effective barrier for the latter, and the system can be mapped onto identical bosons in a double well. For weaker localization, the barrier atoms begin to respond to the light component, leading to an induced attraction between the mobile atoms that may even outweigh their bare intraspecies repulsion. To explain the resulting effects, we derive an effective Hubbard model for the lighter species accounting for the back action of the barrier in correction terms to the lattice parameters. Also the tunneling is drastically affected: by varying the degree of localization of the 'barrier' atoms, the dynamics of intrinsically noninteracting bosons can change from Rabi oscillations to effective pair tunneling. For identical fermions (or fermionized bosons), this leads to the tunneling of attractively bound pairs.

  17. Dynamical spin structure factor of one-dimensional interacting fermions

    NASA Astrophysics Data System (ADS)

    Zyuzin, Vladimir A.; Maslov, Dmitrii L.

    2015-02-01

    We revisit the dynamic spin susceptibility χ (q ,ω ) of one-dimensional interacting fermions. To second order in the interaction, backscattering results in a logarithmic correction to χ (q ,ω ) at q ≪kF , even if the single-particle spectrum is linearized near the Fermi points. Consequently, the dynamic spin structure factor Im χ (q ,ω ) is nonzero at frequencies above the single-particle continuum. In the boson language, this effect results from the marginally irrelevant backscattering operator of the sine-Gordon model. Away from the threshold, the high-frequency tail of Im χ (q ,ω ) due to backscattering is larger than that due to finite mass by a factor of kF/q . We derive the renormalization group equations for the coupling constants of the g -ology model at finite ω and q and find the corresponding expression for χ (q ,ω ) , valid to all orders in the interaction but not in the immediate vicinity of the continuum boundary, where the finite-mass effects become dominant.

  18. Weak lasing in one-dimensional polariton superlattices

    PubMed Central

    Zhang, Long; Xie, Wei; Wang, Jian; Poddubny, Alexander; Lu, Jian; Wang, Yinglei; Gu, Jie; Liu, Wenhui; Xu, Dan; Shen, Xuechu; Rubo, Yuri G.; Altshuler, Boris L.; Kavokin, Alexey V.; Chen, Zhanghai

    2015-01-01

    Bosons with finite lifetime exhibit condensation and lasing when their influx exceeds the lasing threshold determined by the dissipative losses. In general, different one-particle states decay differently, and the bosons are usually assumed to condense in the state with the longest lifetime. Interaction between the bosons partially neglected by such an assumption can smear the lasing threshold into a threshold domain—a stable lasing many-body state exists within certain intervals of the bosonic influxes. This recently described weak lasing regime is formed by the spontaneously symmetry breaking and phase-locking self-organization of bosonic modes, which results in an essentially many-body state with a stable balance between gains and losses. Here we report, to our knowledge, the first observation of the weak lasing phase in a one-dimensional condensate of exciton–polaritons subject to a periodic potential. Real and reciprocal space photoluminescence images demonstrate that the spatial period of the condensate is twice as large as the period of the underlying periodic potential. These experiments are realized at room temperature in a ZnO microwire deposited on a silicon grating. The period doubling takes place at a critical pumping power, whereas at a lower power polariton emission images have the same periodicity as the grating. PMID:25787253

  19. Weak lasing in one-dimensional polariton superlattices.

    PubMed

    Zhang, Long; Xie, Wei; Wang, Jian; Poddubny, Alexander; Lu, Jian; Wang, Yinglei; Gu, Jie; Liu, Wenhui; Xu, Dan; Shen, Xuechu; Rubo, Yuri G; Altshuler, Boris L; Kavokin, Alexey V; Chen, Zhanghai

    2015-03-31

    Bosons with finite lifetime exhibit condensation and lasing when their influx exceeds the lasing threshold determined by the dissipative losses. In general, different one-particle states decay differently, and the bosons are usually assumed to condense in the state with the longest lifetime. Interaction between the bosons partially neglected by such an assumption can smear the lasing threshold into a threshold domain--a stable lasing many-body state exists within certain intervals of the bosonic influxes. This recently described weak lasing regime is formed by the spontaneously symmetry breaking and phase-locking self-organization of bosonic modes, which results in an essentially many-body state with a stable balance between gains and losses. Here we report, to our knowledge, the first observation of the weak lasing phase in a one-dimensional condensate of exciton-polaritons subject to a periodic potential. Real and reciprocal space photoluminescence images demonstrate that the spatial period of the condensate is twice as large as the period of the underlying periodic potential. These experiments are realized at room temperature in a ZnO microwire deposited on a silicon grating. The period doubling takes place at a critical pumping power, whereas at a lower power polariton emission images have the same periodicity as the grating.

  20. Covering by random intervals and one-dimensional continuum percolation

    SciTech Connect

    Domb, C. )

    1989-04-01

    A brief historical introduction is given to the problem of covering a line by random overlapping intervals. The problem for equal intervals was first solved by Whitworth in the 1890s. A brief resume is given of his solution. The advantages of the present author's approach, which uses a Poisson process, are outlined, and a solution is derived by Laplace transforms. The asymptotic behavior as the line becomes long is calculated and is related to the one-dimensional continuum percolation problem. It is shown that as long as the mean interval size is finite, the probability of complete coverage decays exponentially, so that the critical percolation probability p{sub c} = 1. However, as soon as the mean interval size becomes infinite, the critical percolation probability p{sub c} switches to 0. This is in accord with previous results for a lattice model by Chinese workers, but differs from those of Schulman. A possible reason for the discrepancy is a difference in boundary conditions.

  1. Fractal geometry in an expanding, one-dimensional, Newtonian universe.

    PubMed

    Miller, Bruce N; Rouet, Jean-Louis; Le Guirriec, Emmanuel

    2007-09-01

    Observations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, three-dimensional N-body simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one-dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of two of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. For each model at least two scaling regions are identified. By employing criteria from dynamical systems theory it is shown that only one of them can be geometrically significant. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the mu (position, velocity) space. The observed patterns are simply a shadow (projection) of higher-dimensional structure.

  2. Reentrant phase coherence in a quasi-one-dimensional superconductor

    NASA Astrophysics Data System (ADS)

    Ansermet, Diane; Petrovic, Alexander P.; He, Shikun; Chernyshov, Dmitri; Hoesch, Moritz; Salloum, Diala; Gougeon, Patrick; Potel, Michel; Boeri, Lilia; Andersen, Ole K.; Panagopoulos, Christos

    Short coherence lengths characteristic of low-dimensional superconductors are related to high critical fields or temperatures. Fatally, such materials are often sensitive to disorder and suffer from phase fluctuations in the order parameter which diverge with temperature T, magnetic field H or current I. To solve synthesis and fluctuation problems, we propose to build superconductors from inhomogeneous composites of nanofilaments. Single crystals of quasi-one-dimensional Na2-δMo6Se6 featuring Na vacancy disorder (δ ~ 0 . 2) behave as percolative networks of superconducting nanowires. Long range order is established via transverse coupling between individual filaments, yet phase coherence is unstable to fluctuations and localization in the zero-(T, H, I) limit. A region of reentrant phase coherence develops upon raising (T, H, I) and is attributed to an enhancement of the transverse coupling due to electron delocalization. The observed reentrance in the electronic transport coincides with a peak in the Josephson energy EJ at non-zero (T, H, I). Na2-δMo6Se6 is a blueprint for a new generation of low dimensional superconductors with resilience to phase fluctuations at high (T, H, I). This work was supported by the National Research Foundation, Singapore, through Grant NRF-CRP4-2008-04.

  3. One-dimensional nanoferroic rods; synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Ahmed, M. A.; Seddik, U.; Okasha, N.; Imam, N. G.

    2015-11-01

    One-dimensional nanoferroic rods of BaTiO3 were synthesized by improved citrate auto-combustion technology using tetrabutyl titanate. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) have been used to characterize the prepared sample. The results indicated that the crystal structure of BaTiO3 is tetragonal phase with an average crystallite size of 47 nm. SEM image gives a cauliflower-like morphology of the agglomerated nanorods. The stoichiometry of the chemical composition of the BaTiO3 ceramic was confirmed by EDX. TEM micrograph exhibited that BaTiO3 nanoparticles have rod-like shape with an average length of 120 nm and width of 43 nm. AFM was used to investigate the surface topography and its roughness. The topography image in 3D showed that the BaTiO3 particles have a rod shape with an average particle size of 116 nm which in agreement with 3D TEM result.

  4. A one-dimensional model of Nucleosome distribution in DNA

    NASA Astrophysics Data System (ADS)

    Osberg, Brendan; Moebius, Wolfram; Nguyen, Kien; Gerland, Ulrich

    2012-02-01

    Nucleosome positioning along DNA is neither random nor precisely regular. Genome-wide maps of nucleosome positions in various eukaryotes have revealed a common pattern around transcription start sites, involving a nucleosome-free region flanked by a periodic pattern in the average nucleosome density. We take a quantitative mathematical description of the nucleosome pattern, and incorporate specifically bound transcription factors. Our model assumes a dense, one-dimensional gas of particles, however, instead of previous work which assumes fixed-size particles interacting only by exclusion, our model explicitly accounts for transient unwrapping of short segments of nucleosomal DNA. Hence, such particles no longer have a fixed size, but interact by an effective repulsive potential. This model has been succesfully used, by us, to provide a unified description of 12 Hemiascomycota yeast species with a single unified set of model parameters. We incorporate into this model, specifically bound particles, or transcription factors (TF), which serve an important role in gene regulation. Nucleosome distribution patterns have an important influence on TF binding, and can even mediate interactions between transcription factors at a distance. This interaction can account for cooperative or competitive binding between these proteins, and we will discuss the implications this can have on gene regulation.

  5. Topological water wave states in a one-dimensional structure.

    PubMed

    Yang, Zhaoju; Gao, Fei; Zhang, Baile

    2016-01-01

    Topological concepts have been introduced into electronic, photonic, and phononic systems, but have not been studied in surface-water-wave systems. Here we study a one-dimensional periodic resonant surface-water-wave system and demonstrate its topological transition. By selecting three different water depths, we can construct different types of water waves - shallow, intermediate and deep water waves. The periodic surface-water-wave system consists of an array of cylindrical water tanks connected with narrow water channels. As the width of connecting channel varies, the band diagram undergoes a topological transition which can be further characterized by Zak phase. This topological transition holds true for shallow, intermediate and deep water waves. However, the interface state at the boundary separating two topologically distinct arrays of water tanks can exhibit different bands for shallow, intermediate and deep water waves. Our work studies for the first time topological properties of water wave systems, and paves the way to potential management of water waves. PMID:27373982

  6. One-dimensional consolidation in unsaturated soils under cyclic loading

    NASA Astrophysics Data System (ADS)

    Lo, Wei-Cheng; Sposito, Garrison; Lee, Jhe-Wei; Chu, Hsiuhua

    2016-05-01

    The one-dimensional consolidation model of poroelasticity of Lo et al. (2014) for an unsaturated soil under constant loading is generalized to include an arbitrary time-dependent loading. A closed-form solution for the pore water and air pressures along with the total settlement is derived by employing a Fourier series representation in the spatial domain and a Laplace transformation in the time domain. This solution is illustrated for the important example of a fully-permeable soil cylinder with an undrained initial condition acted upon by a periodic stress. Our results indicate that, in terms of a dimensionless time scale, the transient solution decays to zero most slowly in a water-saturated soil, whereas for an unsaturated soil, the time for the transient solution to die out is inversely proportional to the initial water saturation. The generalization presented here shows that the diffusion time scale for pore water in an unsaturated soil is orders of magnitude greater than that in a water-saturated soil, mainly because of the much smaller hydraulic conductivity of the former.

  7. Charge transport through one-dimensional Moiré crystals

    NASA Astrophysics Data System (ADS)

    Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Rocca, Maria Luisa Della; Lafarge, Philippe; Charlier, Jean-Christophe

    2016-01-01

    Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations.

  8. Topological order in interacting one-dimensional Bose Systems

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian; Höning, Michael; Fleischhauer, Michael

    2015-05-01

    We discuss topological aspects of one-dimensional inversion-symmetric systems of interacting bosons, which can be implemented in current experiments with ultra cold atoms. We consider both integer and fractional fillings of a topologically non-trivial Bloch band. Our starting point is the chiral-symmetric Su-Schrieffer-Heeger (SSH) model of non-interacting fermions, which can be realized by hard-core bosons. When the hard-core constraint is removed, we obtain a bosonic system with inversion-symmetry protected topological order. Because the chiral symmetry is broken by finite interactions, the bulk-boundary correspondence of the SSH model is no longer valid. Nevertheless we show that the fractional part of the charge which is localized at the edge can distinguish topologically trivial- from non-trivial states. We generalize our analysis by including nearest neighbor interactions and present a topological classification of the resulting quarter-filling Mott insulating phase. In this case fractionally charged bulk excitations exist, which we identify in the grand-canonical phase diagram. F.G. acknowledges support from the Graduate School of Material Science MAINZ.

  9. Charge transport through one-dimensional Moiré crystals.

    PubMed

    Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Della Rocca, Maria Luisa; Lafarge, Philippe; Charlier, Jean-Christophe

    2016-01-20

    Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations.

  10. One dimensional coordination polymers: Synthesis, crystal structures and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Şahin, Onur

    2016-11-01

    Two new one dimensional (1D) cyanide complexes, namely [M(4-aepy)2(H2O)2][Pt(CN)4], (4-aepy = 4-(2-aminoethyl)pyridine M = Cu(II) (1) or Zn(II) (2)), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. The crystallographic analyses reveal that 1 and 2 are isomorphous and isostructural, and crystallize in the monoclinic system and C2 space group. The Pt(II) ions are coordinated by four cyanide-carbon atoms in the square-planar geometry and the [Pt(CN)4]2- ions act as a counter ion. The M(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4-aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. The crystal structures of 1 and 2 are similar each other and linked via intermolecular hydrogen bonding, Pt⋯π interactions to form 3D supramolecular network. Vibration assignments of all the observed bands are given and the spectral features also supported to the crystal structures of the complexes.

  11. Numerical method of characteristics for one-dimensional blood flow

    NASA Astrophysics Data System (ADS)

    Acosta, Sebastian; Puelz, Charles; Rivière, Béatrice; Penny, Daniel J.; Rusin, Craig G.

    2015-08-01

    Mathematical modeling at the level of the full cardiovascular system requires the numerical approximation of solutions to a one-dimensional nonlinear hyperbolic system describing flow in a single vessel. This model is often simulated by computationally intensive methods like finite elements and discontinuous Galerkin, while some recent applications require more efficient approaches (e.g. for real-time clinical decision support, phenomena occurring over multiple cardiac cycles, iterative solutions to optimization/inverse problems, and uncertainty quantification). Further, the high speed of pressure waves in blood vessels greatly restricts the time step needed for stability in explicit schemes. We address both cost and stability by presenting an efficient and unconditionally stable method for approximating solutions to diagonal nonlinear hyperbolic systems. Theoretical analysis of the algorithm is given along with a comparison of our method to a discontinuous Galerkin implementation. Lastly, we demonstrate the utility of the proposed method by implementing it on small and large arterial networks of vessels whose elastic and geometrical parameters are physiologically relevant.

  12. Inelastic collapse in one-dimensional driven systems under gravity.

    PubMed

    Wakou, Jun'ichi; Kitagishi, Hiroyuki; Sakaue, Takahiro; Nakanishi, Hiizu

    2013-04-01

    We study inelastic collapse in a one-dimensional N-particle system when the system is driven from below under gravity. We investigate the hard-sphere limit of inelastic soft-sphere systems by numerical simulations to find how the collision rate per particle n(coll) increases as a function of the elastic constant of the sphere k when the restitution coefficient e is kept constant. For systems with large enough N>/~20, we find three regimes in e depending on the behavior of n(coll) in the hard-sphere limit: (i) an uncollapsing regime for 1≥e>e(c1), where n(coll) converges to a finite value, (ii) a logarithmically collapsing regime for e(c1)>e>e(c2), where n(coll) diverges as n(coll)~logk, and (iii) a power-law collapsing regime for e(c2)>e>0, where n(coll) diverges as n(coll)~k(α) with an exponent α that depends on N. The power-law collapsing regime shrinks as N decreases and seems not to exist for the system with N=3, while, for large N, the size of the uncollapsing and the logarithmically collapsing regime decreases as e(c1)=/~1-2.6/N and e(c2)=/~1-3.0/N. We demonstrate that this difference between large and small systems exists already in the inelastic collapse without external drive and gravity.

  13. Nucleation and growth of nanoscaled one-dimensional materials

    NASA Astrophysics Data System (ADS)

    Cui, Hongtao

    Nanoscaled one-dimensional materials have attracted great interest due to their novel physical and chemical properties. The purpose of this dissertation is to study the nucleation and growth mechanisms of carbon nanotubes and silicon nitride nanowires with their field emission applications in mind. As a result of this research, a novel methodology has been developed to deposit aligned bamboo-like carbon nanotubes on substrates using a methane and ammonia mixture in microwave plasma enhanced chemical deposition. Study of growth kinetics suggests that the carbon diffusion through bulk catalyst particles controls growth in the initial deposition process. Microstructures of carbon nanotubes are affected by the growth temperature and carbon concentration in the gas phase. High-resolution transmission electron microscope confirms the existence of the bamboo-like structure. Electron diffraction reveals that the iron-based catalyst nucleates and sustains the growth of carbon nanotubes. A nucleation and growth model has been constructed based upon experimental data and observations. In the study of silicon nitride nanoneedles, a vapor-liquid-solid model is employed to explain the nucleation and growth processes. Ammonia plasma etching is proposed to reduce the size of the catalyst and subsequently produce the novel needle-like nanostructure. High-resolution transmission electron microscope shows the structure is well crystallized and composed of alpha-silicon nitride. Other observations in the structure are also explained.

  14. SUSY-hierarchy of one-dimensional reflectionless potentials

    SciTech Connect

    Maydanyuk, Sergei P. . E-mail: maidan@kinr.kiev.ua

    2005-04-01

    A class of one-dimensional reflectionless potentials is studied. It is found that all possible types of the reflectionless potentials can be combined into one SUSY-hierarchy with a constant potential. An approach for determination of a general form of the reflectionless potential on the basis of construction of such a hierarchy by the recurrent method is proposed. A general integral form of interdependence between superpotentials with neighboring numbers of this hierarchy, opening a possibility to find new reflectionless potentials, is found and has a simple analytical view. It is supposed that any possible type of the reflectionless potential can be expressed through finite number of elementary functions (unlike some presentations of the reflectionless potentials, which are constructed on the basis of soliton solutions or are shape invariant in one or many steps with involving scaling of parameters, and are expressed through series). An analysis of absolute transparency existence for the potential which has the inverse power dependence on space coordinate (and here tunneling is possible), i.e., which has the form V (x) = {+-} {alpha}/ vertical bar x-x{sub 0} vertical bar{sup n} (where {alpha} and x{sub 0} are constants, n is natural number), is fulfilled. It is shown that such a potential can be reflectionless at n = 2 only. A SUSY-hierarchy of the inverse power reflectionless potentials is constructed. Isospectral expansions of this hierarchy are analyzed.

  15. Topological water wave states in a one-dimensional structure

    PubMed Central

    Yang, Zhaoju; Gao, Fei; Zhang, Baile

    2016-01-01

    Topological concepts have been introduced into electronic, photonic, and phononic systems, but have not been studied in surface-water-wave systems. Here we study a one-dimensional periodic resonant surface-water-wave system and demonstrate its topological transition. By selecting three different water depths, we can construct different types of water waves - shallow, intermediate and deep water waves. The periodic surface-water-wave system consists of an array of cylindrical water tanks connected with narrow water channels. As the width of connecting channel varies, the band diagram undergoes a topological transition which can be further characterized by Zak phase. This topological transition holds true for shallow, intermediate and deep water waves. However, the interface state at the boundary separating two topologically distinct arrays of water tanks can exhibit different bands for shallow, intermediate and deep water waves. Our work studies for the first time topological properties of water wave systems, and paves the way to potential management of water waves. PMID:27373982

  16. Moving solitons in a one-dimensional fermionic superfluid

    NASA Astrophysics Data System (ADS)

    Efimkin, Dmitry K.; Galitski, Victor

    2015-02-01

    A fully analytical theory of a traveling soliton in a one-dimensional fermionic superfluid is developed within the framework of time-dependent self-consistent Bogoliubov-de Gennes equations, which are solved exactly in the Andreev approximation. The soliton manifests itself in a kinklike profile of the superconducting order parameter and hosts a pair of Andreev bound states in its core. They adjust to the soliton's motion and play an important role in its stabilization. A phase jump across the soliton and its energy decrease with the soliton's velocity and vanish at the critical velocity, corresponding to the Landau criterion, where the soliton starts emitting quasiparticles and becomes unstable. The "inertial" and "gravitational" masses of the soliton are calculated and the former is shown to be orders of magnitude larger than the latter. This results in a slow motion of the soliton in a harmonic trap, reminiscent of the observed behavior of a solitonlike texture in related experiments in cold fermion gases [T. Yefsah et al., Nature (London) 499, 426 (2013), 10.1038/nature12338]. Furthermore, we calculate the full nonlinear dispersion relation of the soliton and solve the classical equations of motion in a trap. The strong nonlinearity at high velocities gives rise to anharmonic oscillatory motion of the soliton. A careful analysis of this anharmonicity may provide a means to experimentally measure the nonlinear soliton spectrum in superfluids.

  17. Carbyne with finite length: The one-dimensional sp carbon

    PubMed Central

    Pan, Bitao; Xiao, Jun; Li, Jiling; Liu, Pu; Wang, Chengxin; Yang, Guowei

    2015-01-01

    Carbyne is the one-dimensional allotrope of carbon composed of sp-hybridized carbon atoms. Definitive evidence for carbyne has remained elusive despite its synthesis and preparation in the laboratory. Given the remarkable technological breakthroughs offered by other allotropes of carbon, including diamond, graphite, fullerenes, carbon nanotubes, and graphene, interest in carbyne and its unusual potential properties remains intense. We report the first synthesis of carbyne with finite length, which is clearly composed of alternating single bonds and triple bonds, using a novel process involving laser ablation in liquid. Spectroscopic analyses confirm that the product is the structure of sp hybridization with alternating carbon-carbon single bonds and triple bonds and capped by hydrogen. We observe purple-blue fluorescence emissions from the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of carbyne. Condensed-phase carbyne crystals have a hexagonal lattice and resemble the white crystalline powder produced by drying a carbyne solution. We also establish that the combination of gold and alcohol is crucial to carbyne formation because carbon-hydrogen bonds can be cleaved with the help of gold catalysts under the favorable thermodynamic environment provided by laser ablation in liquid and because the unique configuration of two carbon atoms in an alcohol molecule matches the elementary entity of carbyne. This laboratory synthesis of carbyne will enable the exploration of its properties and applications. PMID:26601318

  18. Topological phase in one-dimensional Rashba wire

    NASA Astrophysics Data System (ADS)

    Sa-Ke, Wang; Jun, Wang; Jun-Feng, Liu

    2016-07-01

    We study the possible topological phase in a one-dimensional (1D) quantum wire with an oscillating Rashba spin-orbital coupling in real space. It is shown that there are a pair of particle-hole symmetric gaps forming in the bulk energy band and fractional boundary states residing in the gap when the system has an inversion symmetry. These states are topologically nontrivial and can be characterized by a quantized Berry phase ±π or nonzero Chern number through dimensional extension. When the Rashba spin-orbital coupling varies slowly with time, the system can pump out 2 charges in a pumping cycle because of the spin flip effect. This quantized pumping is protected by topology and is robust against moderate disorders as long as the disorder strength does not exceed the opened energy gap. Project supported by the National Natural Science Foundation of China (Grant Nos. 115074045 and 11204187) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20131284).

  19. One-dimensional particle models for heat transfer analysis

    NASA Astrophysics Data System (ADS)

    Bufferand, H.; Ciraolo, G.; Ghendrih, Ph; Tamain, P.; Bagnoli, F.; Lepri, S.; Livi, R.

    2010-11-01

    For a better understanding of Spitzer-Härm closure restrictions and for estimating the relevancy of this expression when collisionnality decreases, an effort is done in developing simple models that aim at catching the physics of the transition from conductive to free-streaming heat flux. In that perspective, one-dimensional particle models are developed to study heat transfer properties in the direction parallel to the magnetic field in tokamaks. These models are based on particles that carry energy at a specific velocity and that can interact with each other or with heat sources. By adjusting the particle dynamics and particle interaction properties, it is possible to generate a broad range of models of growing complexity. The simplest models can be solved analytically and are used to link particle behavior to general macroscopic heat transfer properties. In particular, some configurations recover Fourier's law and make possible to investigate the dependance of thermal conductivity on temperature. Besides, some configurations where local balance is lost require defining non local expression for heat flux. These different classes of models could then be linked to different plasma configurations and used to study transition from collisional to non-collisional plasma.

  20. Topological phase in one-dimensional Rashba wire

    NASA Astrophysics Data System (ADS)

    Sa-Ke, Wang; Jun, Wang; Jun-Feng, Liu

    2016-07-01

    We study the possible topological phase in a one-dimensional (1D) quantum wire with an oscillating Rashba spin–orbital coupling in real space. It is shown that there are a pair of particle–hole symmetric gaps forming in the bulk energy band and fractional boundary states residing in the gap when the system has an inversion symmetry. These states are topologically nontrivial and can be characterized by a quantized Berry phase ±π or nonzero Chern number through dimensional extension. When the Rashba spin–orbital coupling varies slowly with time, the system can pump out 2 charges in a pumping cycle because of the spin flip effect. This quantized pumping is protected by topology and is robust against moderate disorders as long as the disorder strength does not exceed the opened energy gap. Project supported by the National Natural Science Foundation of China (Grant Nos. 115074045 and 11204187) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20131284).

  1. Multi-symplectic, Lagrangian, one-dimensional gas dynamics

    NASA Astrophysics Data System (ADS)

    Webb, G. M.

    2015-05-01

    The equations of Lagrangian, ideal, one-dimensional, compressible gas dynamics are written in a multi-symplectic form using the Lagrangian mass coordinate m and time t as independent variables, and in which the Eulerian position of the fluid element x = x(m, t) is one of the dependent variables. This approach differs from the Eulerian, multi-symplectic approach using Clebsch variables. Lagrangian constraints are used to specify equations for xm, xt, and St consistent with the Lagrangian map, where S is the entropy of the gas. We require St = 0 corresponding to advection of the entropy S with the flow. We show that the Lagrangian Hamiltonian equations are related to the de Donder-Weyl multi-momentum formulation. The pullback conservation laws and the symplecticity conservation laws are discussed. The pullback conservation laws correspond to invariance of the action with respect to translations in time (energy conservation) and translations in m in Noether's theorem. The conservation law due to m-translation invariance gives rise to a novel nonlocal conservation law involving the Clebsch variable r used to impose ∂S(m, t)/∂t = 0. Translation invariance with respect to x in Noether's theorem is associated with momentum conservation. We obtain the Cartan-Poincaré form for the system, and use it to obtain a closed ideal of two-forms representing the equation system.

  2. Charge transport through one-dimensional Moiré crystals

    PubMed Central

    Bonnet, Roméo; Lherbier, Aurélien; Barraud, Clément; Rocca, Maria Luisa Della; Lafarge, Philippe; Charlier, Jean-Christophe

    2016-01-01

    Moiré superlattices were generated in two-dimensional (2D) van der Waals heterostructures and have revealed intriguing electronic structures. The appearance of mini-Dirac cones within the conduction and valence bands of graphene is one of the most striking among the new quantum features. A Moiré superstructure emerges when at least two periodic sub-structures superimpose. 2D Moiré patterns have been particularly investigated in stacked hexagonal 2D atomic lattices like twisted graphene layers and graphene deposited on hexagonal boron-nitride. In this letter, we report both experimentally and theoretically evidence of superlattices physics in transport properties of one-dimensional (1D) Moiré crystals. Rolling-up few layers of graphene to form a multiwall carbon nanotube adds boundaries conditions that can be translated into interference fringes-like Moiré patterns along the circumference of the cylinder. Such a 1D Moiré crystal exhibits a complex 1D multiple bands structure with clear and robust interband quantum transitions due to the presence of mini-Dirac points and pseudo-gaps. Our devices consist in a very large diameter (>80 nm) multiwall carbon nanotubes of high quality, electrically connected by metallic electrodes acting as charge reservoirs. Conductance measurements reveal the presence of van Hove singularities assigned to 1D Moiré superlattice effect and illustrated by electronic structure calculations. PMID:26786067

  3. Transmission properties of one-dimensional ternary plasma photonic crystals

    SciTech Connect

    Shiveshwari, Laxmi; Awasthi, S. K.

    2015-09-15

    Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter.

  4. Scattering by infinitely rising one-dimensional potentials

    NASA Astrophysics Data System (ADS)

    Ferreira, E. M.; Sesma, J.

    2015-12-01

    Infinitely rising one-dimensional potentials constitute impenetrable barriers which reflect totally any incident wave. However, the scattering by such kind of potentials is not structureless: resonances may occur for certain values of the energy. Here we consider the problem of scattering by the members of a family of potentials Va(x) = - sgn(x) | x | a, where sgn represents the sign function and a is a positive rational number. The scattering function and the phase shifts are obtained from global solutions of the Schrödinger equation. For the determination of the Gamow states, associated to resonances, we exploit their close relation with the eigenvalues of the PT-symmetric Hamiltonians with potentials VaPT(x) = - i sgn(x) | x | a. Calculation of the time delay in the scattering at real energies is used to characterize the resonances. As an additional result, the breakdown of the PT-symmetry of the family of potentials VaPT for a < 3 may be conjectured.

  5. A disorder-enhanced quasi-one-dimensional superconductor

    PubMed Central

    Petrović, A. P.; Ansermet, D.; Chernyshov, D.; Hoesch, M.; Salloum, D.; Gougeon, P.; Potel, M.; Boeri, L.; Panagopoulos, C.

    2016-01-01

    A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2−δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials. PMID:27448209

  6. A Smart Colorful Supercapacitor with One Dimensional Photonic Crystals

    PubMed Central

    Liu, Cihui; Liu, Xing; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin

    2015-01-01

    To meet the pressing demands for portable and flexible equipment in contemporary society, developing flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and ease of strongly required. However, estimating the state-of-charge of existing supercapacitors is difficult, and thus their service life is limited. In this study, we fabricate a flexible color indicative supercapacitor device with mesoporous polyaniline (mPANI)/Poly(N-Isopropyl acrylamide-Graphene Oxide-Acrylic Acid) (P(NiPPAm-GO-AA)) one dimensional photonic crystals (1DPCs) as the electrode material through a low-cost, eco-friendly, and scalable fabrication process. We found that the state-of-charge could be monitored by the structural color oscillation due to the change in the photonic band gap position of the 1DPCs. The flexible 1DPCs supercapacitor is thin at 3 mm and exhibits good specific capacitance of 22.6 F g−1 with retention of 91.1% after 3,000 cycles. This study shows the application of the 1DPCs supercapacitor as a visual ultrathin power source. The technology may find many applications in future wearable electronics. PMID:26689375

  7. A disorder-enhanced quasi-one-dimensional superconductor.

    PubMed

    Petrović, A P; Ansermet, D; Chernyshov, D; Hoesch, M; Salloum, D; Gougeon, P; Potel, M; Boeri, L; Panagopoulos, C

    2016-01-01

    A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2-δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials. PMID:27448209

  8. A disorder-enhanced quasi-one-dimensional superconductor.

    PubMed

    Petrović, A P; Ansermet, D; Chernyshov, D; Hoesch, M; Salloum, D; Gougeon, P; Potel, M; Boeri, L; Panagopoulos, C

    2016-01-01

    A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2-δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials.

  9. Solitary Wave in One-dimensional Buckyball System at Nanoscale.

    PubMed

    Xu, Jun; Zheng, Bowen; Liu, Yilun

    2016-01-01

    We have studied the stress wave propagation in one-dimensional (1-D) nanoscopic buckyball (C60) system by molecular dynamics (MD) simulation and quantitative modeling. Simulation results have shown that solitary waves are generated and propagating in the buckyball system through impacting one buckyball at one end of the buckyball chain. We have found the solitary wave behaviors are closely dependent on the initial temperature and impacting speed of the buckyball chain. There are almost no dispersion and dissipation of the solitary waves (stationary solitary wave) for relatively low temperature and high impacting speed. While for relatively high temperature and low impacting speed the profile of the solitary waves is highly distorted and dissipated after propagating several tens of buckyballs. A phase diagram is proposed to describe the effect of the temperature and impacting speed on the solitary wave behaviors in buckyball system. In order to quantitatively describe the wave behavior in buckyball system, a simple nonlinear-spring model is established, which can describe the MD simulation results at low temperature very well. The results presented in this work may lay a solid step towards the further understanding and manipulation of stress wave propagation and impact energy mitigation at nanoscale. PMID:26891624

  10. A Smart Colorful Supercapacitor with One Dimensional Photonic Crystals

    NASA Astrophysics Data System (ADS)

    Liu, Cihui; Liu, Xing; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin

    2015-12-01

    To meet the pressing demands for portable and flexible equipment in contemporary society, developing flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and ease of strongly required. However, estimating the state-of-charge of existing supercapacitors is difficult, and thus their service life is limited. In this study, we fabricate a flexible color indicative supercapacitor device with mesoporous polyaniline (mPANI)/Poly(N-Isopropyl acrylamide-Graphene Oxide-Acrylic Acid) (P(NiPPAm-GO-AA)) one dimensional photonic crystals (1DPCs) as the electrode material through a low-cost, eco-friendly, and scalable fabrication process. We found that the state-of-charge could be monitored by the structural color oscillation due to the change in the photonic band gap position of the 1DPCs. The flexible 1DPCs supercapacitor is thin at 3 mm and exhibits good specific capacitance of 22.6 F g-1 with retention of 91.1% after 3,000 cycles. This study shows the application of the 1DPCs supercapacitor as a visual ultrathin power source. The technology may find many applications in future wearable electronics.

  11. DEPTH-CHARGE static and time-dependent perturbation/sensitivity system for nuclear reactor core analysis. Revision I. [DEPTH-CHARGE code

    SciTech Connect

    White, J.R.

    1985-04-01

    This report provides the background theory, user input, and sample problems required for the efficient application of the DEPTH-CHARGE system - a code black for both static and time-dependent perturbation theory and data sensitivity analyses. The DEPTH-CHARGE system is of modular construction and has been implemented within the VENTURE-BURNER computational system at Oak Ridge National Laboratory. The DEPTH module (coupled with VENTURE) solves for the three adjoint functions of Depletion Perturbation Theory and calculates the desired time-dependent derivatives of the response with respect to the nuclide concentrations and nuclear data utilized in the reference model. The CHARGE code is a collection of utility routines for general data manipulation and input preparation and considerably extends the usefulness of the system through the automatic generation of adjoint sources, estimated perturbed responses, and relative data sensitivity coefficients. Combined, the DEPTH-CHARGE system provides, for the first time, a complete generalized first-order perturbation/sensitivity theory capability for both static and time-dependent analyses of realistic multidimensional reactor models. This current documentation incorporates minor revisions to the original DEPTH-CHARGE documentation (ORNL/CSD-78) to reflect some new capabilities within the individual codes.

  12. Heterolayered, one-dimensional nanobuilding block mat batteries.

    PubMed

    Choi, Keun-Ho; Cho, Sung-Ju; Chun, Sang-Jin; Yoo, Jong Tae; Lee, Chang Kee; Kim, Woong; Wu, Qinglin; Park, Sang-Bum; Choi, Don-Ha; Lee, Sun-Young; Lee, Sang-Young

    2014-10-01

    The rapidly approaching smart/wearable energy era necessitates advanced rechargeable power sources with reliable electrochemical properties and versatile form factors. Here, as a unique and promising energy storage system to address this issue, we demonstrate a new class of heterolayered, one-dimensional (1D) nanobuilding block mat (h-nanomat) battery based on unitized separator/electrode assembly (SEA) architecture. The unitized SEAs consist of wood cellulose nanofibril (CNF) separator membranes and metallic current collector-/polymeric binder-free electrodes comprising solely single-walled carbon nanotube (SWNT)-netted electrode active materials (LiFePO4 (cathode) and Li4Ti5O12 (anode) powders are chosen as model systems to explore the proof of concept for h-nanomat batteries). The nanoporous CNF separator plays a critical role in securing the tightly interlocked electrode-separator interface. The SWNTs in the SEAs exhibit multifunctional roles as electron conductive additives, binders, current collectors and also non-Faradaic active materials. This structural/physicochemical uniqueness of the SEAs allows significant improvements in the mass loading of electrode active materials, electron transport pathways, electrolyte accessibility and misalignment-proof of separator/electrode interface. As a result, the h-nanomat batteries, which are easily fabricated by stacking anode SEA and cathode SEA, provide unprecedented advances in the electrochemical performance, shape flexibility and safety tolerance far beyond those achievable with conventional battery technologies. We anticipate that the h-nanomat batteries will open 1D nanobuilding block-driven new architectural design/opportunity for development of next-generation energy storage systems.

  13. Hardening transition in a one-dimensional model for ferrogels.

    PubMed

    Annunziata, Mario Alberto; Menzel, Andreas M; Löwen, Hartmut

    2013-05-28

    We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance.

  14. Tunneling dynamics of two interacting one-dimensional particles

    NASA Astrophysics Data System (ADS)

    Gharashi, Seyed Ebrahim; Blume, D.

    2015-09-01

    We present one-dimensional simulation results for the cold-atom tunneling experiments by the Heidelberg group [Zürn et al., Phys. Rev. Lett. 108, 075303 (2012), 10.1103/PhysRevLett.108.075303; Zürn et al., Phys. Rev. Lett. 111, 175302 (2013), 10.1103/PhysRevLett.111.175302] on one or two 6Li atoms confined by a potential that consists of an approximately harmonic optical trap plus a linear magnetic-field gradient. At the noninteracting particle level, we find that the Wentzel-Kramers-Brillouin approximation may not be used as a reliable tool to extract the trapping potential parameters from the experimentally measured tunneling data. We use our numerical calculations along with the experimental tunneling rates for the noninteracting system to reparametrize the trapping potential. The reparametrized trapping potentials serve as input for our simulations of two interacting particles. For two interacting (distinguishable) atoms on the upper branch, we reproduce the experimentally measured tunneling rates, which vary over several orders of magnitude, fairly well. For infinitely strong interaction strength, we compare the time dynamics with that of two identical fermions and discuss the implications of fermionization on the dynamics. For two attractively interacting atoms on the molecular branch, we find that single-particle tunneling dominates for weakly attractive interactions, while pair tunneling dominates for strongly attractive interactions. Our first set of calculations yields qualitative but not quantitative agreement with the experimentally measured tunneling rates. We obtain quantitative agreement with the experimentally measured tunneling rates if we allow for a weakened radial confinement.

  15. Spectroscopy of one-dimensionally inhomogeneous media with quadratic nonlinearity

    SciTech Connect

    Golubkov, A A; Makarov, Vladimir A

    2011-11-30

    We present a brief review of the results of fifty years of development efforts in spectroscopy of one-dimensionally inhomogeneous media with quadratic nonlinearity. The recent original results obtained by the authors show the fundamental possibility of determining, from experimental data, the coordinate dependences of complex quadratic susceptibility tensor components of a onedimensionally inhomogeneous (along the z axis) medium with an arbitrary frequency dispersion, if the linear dielectric properties of the medium also vary along the z axis and are described by a diagonal tensor of the linear dielectric constant. It is assumed that the medium in question has the form of a plane-parallel plate, whose surfaces are perpendicular to the direction of the inhomogeneity. Using the example of several components of the tensors X{sup (2)}(z, {omega}{sub 1} {+-} {omega}{sub 2}; {omega}{sub 1}, {+-} {omega}{sub 2}), we describe two methods for finding their spatial profiles, which differ in the interaction geometry of plane monochromatic fundamental waves with frequencies {omega}{sub 1} and {omega}{sub 2}. The both methods are based on assessing the intensity of the waves propagating from the plate at the sum or difference frequency and require measurements over a range of angles of incidence of the fundamental waves. Such measurements include two series of additional estimates of the intensities of the waves generated under special conditions by using the test and additional reference plates, which eliminates the need for complicated phase measurements of the complex amplitudes of the waves at the sum (difference) frequency.

  16. One dimensional blood flow in a planetocentric orbit

    NASA Astrophysics Data System (ADS)

    Haranas, Ioannis; Gkigkitzis, Ioannis

    2012-05-01

    All life on earth is accustomed to the presence of gravity. When gravity is altered, biological processes can go awry. It is of great importance to ensure safety during a spaceflight. Long term exposure to microgravity can trigger detrimental physiological responses in the human body. Fluid redistribution coupled with fluid loss is one of the effects. In particular, in microgravity blood volume is shifted towards the thorax and head. Sympathetic nervous system-induced vasoconstriction is needed to maintain arterial pressure, while venoconstriction limits venous pooling of blood prevents further reductions in venous return of blood to the heart. In this paper, we modify an existing one dimensional blood flow model with the inclusion of the hydrostatic pressure gradient that further depends on the gravitational field modified by the oblateness and rotation of the Earth. We find that the velocity of the blood flow VB is inversely proportional to the blood specific volume d, also proportional to the oblateness harmonic coefficient J2, the angular velocity of the Earth ωE, and finally proportional to an arbitrary constant c. For c = -0.39073 and ξH = -0.5 mmHg, all orbits result to less blood flow velocities than that calculated on the surface of the Earth. From all considered orbits, elliptical polar orbit of eccentricity e = 0.2 exhibit the largest flow velocity VB = 1.031 m/s, followed by the orbits of inclination i = 45°and 0°. The Earth's oblateness and its rotation contribute a 0.7% difference to the blood flow velocity.

  17. Two dimensionality in quasi-one-dimensional cobalt oxides

    NASA Astrophysics Data System (ADS)

    Sugiyama, J.; Nozaki, H.; Brewer, J. H.; Ansaldo, E. J.; Morris, G. D.; Takami, T.; Ikuta, H.; Mizutani, U.

    2006-03-01

    Magnetism of quasi-one-dimensional (1D) cobalt oxides ACoO ( A=Ca, Sr and Ba, n=1-5 and ∞) was investigated by μ+SR using polycrystalline samples, at temperatures from 300 K down to 1.8 K. The wTF- μ+SR experiments showed the existence of a magnetic transition in all six samples investigated. The onset temperature of the transition (Tcon) was found to decrease with n; that is, 100±25, 90±10, 85±10, 65±10 50±10, and 15±1 K for n=1-5, and ∞, respectively. In particular, for the samples with n=2-5, Tcon was detected only by the present μ+SR measurements. A muon spin oscillation was clearly observed in both Ca 3Co 2O 6(n=1) and BaCoO 3(n=∞), whereas only a fast relaxation is apparent even at 1.8 K in the other four samples ( n=2-5). Taking together with the fact that the paramagnetic Curie temperature ranges from -150 to -200 K for the compound with n=2 and 3, the μ+SR result indicates that a two-dimensional (2D) short-range antiferromagnetic (AF) order, which has been thought to be unlikely to exist at high T due to a relatively strong 1D F interaction, appears below Tcon for all compounds with n=1-5; but quasi-static long-range AF order formed only in Ca 3Co 2O 6, below 25 K. For BaCoO 3(n=∞), as T decreased from 300 K, 1D F order appeared below 53 K, and a sharp 2D AF transition occurred at 15 K.

  18. Linear and nonlinear compact modes in quasi-one-dimensional flatband systems

    NASA Astrophysics Data System (ADS)

    López-González, Dany; Molina, Mario I.

    2016-04-01

    We examine analytically and numerically the spectral properties of three quasi-one-dimensional lattices, namely, kagome, Lieb, and stub lattices, which are characterized for having flatbands in their spectrum. It is observed that the degenerate eigenmodes modes of these flatbands form a Starklike ladder where each mode is shifted by one lattice site. Their combination can give rise to compact modes that do not diffract due to a geometrical phase cancellation. For all three cases we computed the stability of the fundamental band mode against perturbation of their amplitude and phase, the effect of possible anisotropy of the couplings, and the presence of small random perturbations of the coupling. For the Lieb and stub ribbon, the compact mode turns out to be quite robust and the flatband survives, while for the kagome ribbon, the compact mode is destroyed and the flatband is lost. When adding nonlinear effects, the compact mode turns out to be also a nonlinear eigenvector, with a power curve that is proportional to the eigenvalue and exists for any eigenvalue, in marked contrast to the usual case of discrete solitons, which can exist only outside the linear bands. These properties look promising for a future design of a robust system for long-distance propagation of information.

  19. One-dimensional daisyworld: spatial interactions and pattern formation.

    PubMed

    Adams, B; Carr, J; Lenton, T M; White, A

    2003-08-21

    The zero-dimensional daisyworld model of Watson and Lovelock (1983) demonstrates that life can unconsciously regulate a global environment. Here that model is extended to one dimension, incorporating a distribution of incoming solar radiation and diffusion of heat consistent with a spherical planet. Global regulatory properties of the original model are retained. The daisy populations are initially restricted to hospitable regions of the surface but exert both global and local feedback to increase this habitable area, eventually colonizing the whole surface. The introduction of heat diffusion destabilizes the coexistence equilibrium of the two daisy types. In response, a striped pattern consisting of blocks of all black or all white daisies emerges. There are two mechanisms behind this pattern formation. Both are connected to the stability of the system and an overview of the mathematics involved is presented. Numerical experiments show that this pattern is globally determined. Perturbations in one region have an impact over the whole surface but the regulatory properties of the system are not compromised by transient perturbations. The relevance of these results to the Earth and the wider climate modelling field is discussed. PMID:12875827

  20. Concerning isothermal self-similar blast waves. I - One-dimensional flow and its stability. II - Two-dimensional flow and its stability. [in stellar atmosphere

    NASA Technical Reports Server (NTRS)

    Lerche, I.

    1978-01-01

    One-dimensional self-similar isothermal flow behind a blast wave propagating in a medium whose density varies with distance is investigated for the cases of one-dimensional and two-dimensional flow. The isothermal flow model is adopted as an alternative to adiabatic models of self-similar flow, which neglect heat flux. The topology of the one-dimensional flow solutions, the singularities, and the influence of boundary conditions are discussed; the instability of the isothermal blast waves against nonself-similar perturbations is also considered. The number of critical points in the two-dimensional solutions is found to vary from the number in the one-dimensional problem.

  1. Molecular Self-Assembly into One-Dimensional Nanostructures

    PubMed Central

    PALMER, LIAM C.; STUPP, SAMUEL I.

    2008-01-01

    CONSPECTUS Self-assembly of small molecules into one-dimensional nanostructures offers many potential applications in electronically and biologically active materials. The recent advances discussed in this Account demonstrate how researchers can use the fundamental principles of supramolecular chemistry to craft the size, shape, and internal structure of nanoscale objects. In each system described here, we used atomic force microscopy (AFM) and transmission electron microscopy (TEM) to study the assembly morphology. Circular dichroism, nuclear magnetic resonance, infrared, and optical spectroscopy provided additional information about the self-assembly behavior in solution at the molecular level. Dendron rod–coil molecules self-assemble into flat or helical ribbons. They can incorporate electronically conductive groups and can be mineralized with inorganic semiconductors. To understand the relative importance of each segment in forming the supramolecular structure, we synthetically modified the dendron, rod, and coil portions. The self-assembly depended on the generation number of the dendron, the number of hydrogen-bonding functions, and the length of the rod and coil segments. We formed chiral helices using a dendron–rod–coil molecule prepared from an enantiomerically enriched coil. Because helical nanostructures are important targets for use in biomaterials, nonlinear optics, and stereoselective catalysis, researchers would like to precisely control their shape and size. Tripeptide-containing peptide lipid molecules assemble into straight or twisted nanofibers in organic solvents. As seen by AFM, the sterics of bulky end groups can tune the helical pitch of these peptide lipid nanofibers in organic solvents. Furthermore, we demonstrated the potential for pitch control using trans-to-cis photoisomerization of a terminal azobenzene group. Other molecules called peptide amphiphiles (PAs) are known to assemble in water into cylindrical nanostructures that

  2. Bioinspired one-dimensional materials for directional liquid transport.

    PubMed

    Ju, Jie; Zheng, Yongmei; Jiang, Lei

    2014-08-19

    One-dimensional materials (1D) capable of transporting liquid droplets directionally, such as spider silks and cactus spines, have recently been gathering scientists' attention due to their potential applications in microfluidics, textile dyeing, filtration, and smog removal. This remarkable property comes from the arrangement of the micro- and nanostructures on these organisms' surfaces, which have inspired chemists to develop methods to prepare surfaces with similar directional liquid transport ability. In this Account, we report our recent progress in understanding how this directional transport works, as well our advances in the design and fabrication of bioinspired 1D materials capable of transporting liquid droplets directionally. To begin, we first discuss some basic theories on droplet directional movement. Then, we discuss the mechanism of directional transport of water droplets on natural spider silks. Upon contact with water droplets, the spider silk undergoes what is known as a wet-rebuilt, which forms periodic spindle-knots and joints. We found that the resulting gradient of Laplace pressure and surface free energy between the spindle-knots and joints account for the cooperative driving forces to transport water droplets directionally. Next, we discuss the directional transport of water droplets on desert cactus. The integration of multilevel structures of the cactus and the resulting integration of multiple functions together allow the cactus spine to transport water droplets continuously from tip to base. Based on our studies of natural spider silks and cactus spines, we have prepared a series of artificial spider silks (A-SSs) and artificial cactus spines (A-CSs) with various methods. By changing the surface roughness and chemical compositions of the artificial spider silks' spindle-knots, or by introducing stimulus-responsive molecules, such as thermal-responsive and photoresponsive molecules, onto the spindle-knots, we can reversibly manipulate

  3. Extended forward sensitivity analysis of one-dimensional isothermal flow

    SciTech Connect

    Johnson, M.; Zhao, H.

    2013-07-01

    Sensitivity analysis and uncertainty quantification is an important part of nuclear safety analysis. In this work, forward sensitivity analysis is used to compute solution sensitivities on 1-D fluid flow equations typical of those found in system level codes. Time step sensitivity analysis is included as a method for determining the accumulated error from time discretization. The ability to quantify numerical error arising from the time discretization is a unique and important feature of this method. By knowing the relative sensitivity of time step with other physical parameters, the simulation is allowed to run at optimized time steps without affecting the confidence of the physical parameter sensitivity results. The time step forward sensitivity analysis method can also replace the traditional time step convergence studies that are a key part of code verification with much less computational cost. One well-defined benchmark problem with manufactured solutions is utilized to verify the method; another test isothermal flow problem is used to demonstrate the extended forward sensitivity analysis process. Through these sample problems, the paper shows the feasibility and potential of using the forward sensitivity analysis method to quantify uncertainty in input parameters and time step size for a 1-D system-level thermal-hydraulic safety code. (authors)

  4. Simulation of magnetic island dynamics under resonant magnetic perturbation with the TEAR code and validation of the results on T-10 tokamak data

    NASA Astrophysics Data System (ADS)

    Ivanov, N. V.; Kakurin, A. M.

    2014-10-01

    Simulation of the magnetic island evolution under Resonant Magnetic Perturbation (RMP) in rotating T-10 tokamak plasma is presented with intent of TEAR code experimental validation. In the T-10 experiment chosen for simulation, the RMP consists of a stationary error field, a magnetic field of the eddy current in the resistive vacuum vessel and magnetic field of the externally applied controlled halo current in the plasma scrape-off layer (SOL). The halo-current loop consists of a rail limiter, plasma SOL, vacuum vessel, and external part of the circuit. Effects of plasma resistivity, viscosity, and RMP are taken into account in the TEAR code based on the two-fluid MHD approximation. Radial distribution of the magnetic flux perturbation is calculated with account of the externally applied RMP. A good agreement is obtained between the simulation results and experimental data for the cases of preprogrammed and feedback-controlled halo current in the plasma SOL.

  5. Simulation of magnetic island dynamics under resonant magnetic perturbation with the TEAR code and validation of the results on T-10 tokamak data

    SciTech Connect

    Ivanov, N. V.; Kakurin, A. M.

    2014-10-15

    Simulation of the magnetic island evolution under Resonant Magnetic Perturbation (RMP) in rotating T-10 tokamak plasma is presented with intent of TEAR code experimental validation. In the T-10 experiment chosen for simulation, the RMP consists of a stationary error field, a magnetic field of the eddy current in the resistive vacuum vessel and magnetic field of the externally applied controlled halo current in the plasma scrape-off layer (SOL). The halo-current loop consists of a rail limiter, plasma SOL, vacuum vessel, and external part of the circuit. Effects of plasma resistivity, viscosity, and RMP are taken into account in the TEAR code based on the two-fluid MHD approximation. Radial distribution of the magnetic flux perturbation is calculated with account of the externally applied RMP. A good agreement is obtained between the simulation results and experimental data for the cases of preprogrammed and feedback-controlled halo current in the plasma SOL.

  6. Applications of One-Dimensional Nanomaterials for Stretchable Electronics

    NASA Astrophysics Data System (ADS)

    Xu, Feng

    Electronics that can be stretched and/or conformal to curvilinear surfaces has recently attracted broad attention. Success of stretchable electronics depends on the availability of electronic materials and structures that can be highly stretched, compressed, bent, and twisted. One-dimensional (1D) nanomaterials are expected to aid the development of the stretchable electronic systems by improving performance, expanding integration possibilities, and potentially lowering cost, due to their superior mechanical/electronic/optical properties, high aspect ratios, and compatibility with bulk synthesis. This dissertation is primarily focused on the application of 1D nanomaterials, including silicon nanowires (SiNWs), carbon nanotubes (CNTs) and silver nanowires (AgNWs) for stretchable electronics. The mechanical properties of SiNWs, grown by the vapor-liquid-solid process, were first studied with in situ tensile tests inside a scanning electron microscope (SEM). It was found that the fracture strain increased from 2.7% to about 12% when the NW diameter decreased from 60 to 15 nm. The Young's modulus decreased while the fracture strength increased up to 12.2 GPa, as the nanowire diameter decreased. The fracture strength also increased with the decrease of the side surface area. Repeated loading and unloading during tensile tests demonstrated that the nanowires are linear elastic until fracture without appreciable plasticity. Then, SiNW coils were fabricated on elastomeric substrates by a controlled buckling process. SiNWs were first transferred onto prestrained and ultraviolet/ozone (UVO)-treated poly(dimethylsiloxane) (PDMS) substrates and buckled upon release of the prestrain. Two buckling modes (the in-plane wavy mode and the three-dimensional coiled mode) were found; a transition between them was achieved by controlling the UVO treatment of PDMS. Structural characterization revealed that the NW coils were oval-shaped. The oval-shaped NW coils exhibited very large

  7. Unified One-Dimensional Simulations of Gamma-Ray Line Emission from Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Milne, P. A.; Hungerford, A. L.; Fryer, C. L.; Evans, T. M.; Urbatsch, T. J.; Boggs, S. E.; Isern, J.; Bravo, E.; Hirschmann, A.; Kumagai, S.; Pinto, P. A.; The, L.-S.

    2004-10-01

    The light curves of Type Ia supernovae (SNe Ia) are powered by gamma rays emitted by the decay of radioactive elements such as 56Ni and its decay products. These gamma rays are downscattered, absorbed, and eventually reprocessed into the optical emission that makes up the bulk of all SN observations. Detection of the gamma rays that escape the expanding star provide the only direct means to study this power source for SN Ia light curves. Unfortunately, disagreements between calculations for the gamma-ray lines have made it difficult to interpret any gamma-ray observations. Here we present a detailed comparison of the major gamma-ray line transport codes for a series of one-dimensional SN Ia models. Discrepancies in past results were due to errors in the codes, and the corrected versions of the seven different codes yield very similar results. This convergence of the simulation results allows us to infer more reliable information from the current set of gamma-ray observations of SNe Ia. The observations of SN 1986G, SN 1991T, and SN 1998bu are consistent with explosion models based on their classification: subluminous, superluminous, and normally luminous, respectively.

  8. Spontaneous Charge Carrier Localization in Extended One-Dimensional Systems

    NASA Astrophysics Data System (ADS)

    Vlček, Vojtěch; Eisenberg, Helen R.; Steinle-Neumann, Gerd; Neuhauser, Daniel; Rabani, Eran; Baer, Roi

    2016-05-01

    Charge carrier localization in extended atomic systems has been described previously as being driven by disorder, point defects, or distortions of the ionic lattice. Here we show for the first time by means of first-principles computations that charge carriers can spontaneously localize due to a purely electronic effect in otherwise perfectly ordered structures. Optimally tuned range-separated density functional theory and many-body perturbation calculations within the G W approximation reveal that in trans-polyacetylene and polythiophene the hole density localizes on a length scale of several nanometers. This is due to exchange-induced translational symmetry breaking of the charge density. Ionization potentials, optical absorption peaks, excitonic binding energies, and the optimally tuned range parameter itself all become independent of polymer length as it exceeds the critical localization length. Moreover, we find that lattice disorder and the formation of a polaron result from the charge localization in contrast to the traditional view that lattice distortions precede charge localization. Our results can explain experimental findings that polarons in conjugated polymers form instantaneously after exposure to ultrafast light pulses.

  9. The seasonal effect in one-dimensional Daisyworld.

    PubMed

    Biton, Eli; Gildor, Hezi

    2012-12-01

    We have studied the effects of seasonal Solar Radiation Forcing (SRF) on the climate self-regulatory capability of life, using a latitudinal-dependent Daisyworld model. Because the seasonal polarity of SRF increases poleward, habitable conditions exist in the equatorial regions year round, whereas, in the high latitudes, harsh winters cause annual extinction of life, and only the summers are inhabited or regulated by life. Seasonality affects climate regulation by two major mechanisms: (1) the cold winter conditions in the high latitudes reduce the global temperature below the optimal temperature; (2) during summer, life experiences higher SRF anomalies and, therefore, shifts to higher albedo when compared to annual mean SRF. In turn, a full capacity for temperature regulation is reached at lower SRF, and the range of SRF over which life regulates climate is significantly reduced. Lastly, initiation/extinction of life at low/highly-perturbed SRF occurs at the poles. Therefore, an irreversible global extinction occurs once life passes its regulatory capacity in the poles. We conduct extensive sensitivity analyses on various model parameters (latitudinal heat diffusion, heat capacity, and population death rate), strengthening the generality/robustness of the above net seasonal effects. Applications to other SRF fluctuation, as Milankovitch cycles are discussed.

  10. One-dimensional statistical parametric mapping in Python.

    PubMed

    Pataky, Todd C

    2012-01-01

    Statistical parametric mapping (SPM) is a topological methodology for detecting field changes in smooth n-dimensional continua. Many classes of biomechanical data are smooth and contained within discrete bounds and as such are well suited to SPM analyses. The current paper accompanies release of 'SPM1D', a free and open-source Python package for conducting SPM analyses on a set of registered 1D curves. Three example applications are presented: (i) kinematics, (ii) ground reaction forces and (iii) contact pressure distribution in probabilistic finite element modelling. In addition to offering a high-level interface to a variety of common statistical tests like t tests, regression and ANOVA, SPM1D also emphasises fundamental concepts of SPM theory through stand-alone example scripts. Source code and documentation are available at: www.tpataky.net/spm1d/.

  11. Fabrication and characterization of one dimensional zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Cheng, Chun

    In this thesis, one dimensional (1D) ZnO nanostructures with controlled morphologies, defects and alignment have been fabricated by a simple vapor transfer method. The crystal structures, interfaces, growth mechanisms and optical properties of ZnO nanostructures have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Great efforts have been devoted to the patterned growth and assembly of ZnO nanostructures as well as the stability of ZnO nanowires (NWs). Using carbonized photoresists, a simple and very effective method has been developed for fabricating and patterning high-quality ZnO NW arrays. ZnO NWs from this method show excellent alignment, crystal quality, and optical properties that are independent of the substrates. The carbonized photoresists provide perfect nucleation sites for the growth of aligned ZnO NWs and also perfectly connect to the NWs to form ideal electrodes. This approach is further extended to realize large area growth of different forms of ZnO NW arrays (e.g., the horizontal growth and multilayered ZnO NW arrays) on other kinds of carbon-based materials. In addition, the as-synthesized vertically aligned ZnO NW arrays show a low weighted reflectance (Rw) and can be used as antireflection coatings. Moreover, non c-axis growth of 1D ZnO nanostructures (e.g., nanochains, nanobrushes and nanobelts) and defect related 1D ZnO nanostructures (e.g., Y-shaped twinned nanobelts and hierarchical nanostructures decorated by flowers induced by screw dislocations) is also present. Using direct oxidization of pure Zn at high temperatures in air, uniformed ZnO NWs and tetrapods have been fabricated. The spatially-resolved PL study on these two kinds of nanostructures suggests that the defects leading to the green luminescence (GL) should originate from the structural changes along the legs of the tetrapods. Surface defects in these ZnO nanostructures play an unimportant

  12. One dimensional PIC simulation of relativistic Buneman instability

    NASA Astrophysics Data System (ADS)

    Rajawat, Roopendra Singh; Sengupta, Sudip

    2016-10-01

    Spatio-temporal evolution of the relativistic Buneman instability has been investigated in one dimension using an in-house developed particle-in-cell simulation code. Starting from the excitation of the instability, its evolution has been followed numerically till its quenching and beyond. The simulation results have been quantitatively compared with the fluid theory and are found to be in conformity with the well known fact that the maximum growth rate (γmax) reduces due to relativistic effects and varies with γ e 0 and m/M as γ m a x ˜ /√{ 3 } 2 √{ γ e 0 } ( /m 2 M ) 1 / 3 , where γ e 0 is the Lorentz factor associated with the initial electron drift velocity (v0) and (m/M) is the electron to ion mass ratio. Further it is observed that in contrast to the non-relativistic results [A. Hirose, Plasma Phys. 20, 481 (1978)] at the saturation point, the ratio of electrostatic field energy density ( ∑ k | E k | 2 / 8 π ) to initial drift kinetic energy density (W0) scales with γ e 0 as ˜ 1 / γe 0 2 . This novel result on the scaling of energy densities has been found to be in quantitative agreement with the scalings derived using fluid theory.

  13. WONDY V: a one-dimensional finite-difference wave-propagation code

    SciTech Connect

    Kipp, M.E.; Lawrence, R.J.

    1982-06-01

    WONDY V solves the finite difference analogs to the Lagrangian equations of motion in one spatial dimension (planar, cylindrical, or spherical). Simulations of explosive detonation, energy deposition, plate impact, and dynamic fracture are possible, using a variety of existing material models. In addition, WONDY has proven to be a powerful tool in the evaluation of new constitutive models. A preprocessor is available to allocate storage arrays commensurate with problem size, and automatic rezoning may be employed to improve resolution. This document provides a description of the equations solved, available material models, operating instructions, and sample problems.

  14. Natural circulation in a liquid metal one-dimensional loop

    NASA Astrophysics Data System (ADS)

    Tarantino, M.; De Grandis, S.; Benamati, G.; Oriolo, F.

    2008-06-01

    A wide use of pure lead, as well as its alloys (such as lead-bismuth, lead-lithium), is foreseen in several nuclear-related fields: it is studied as coolant in critical and sub-critical nuclear reactors, as spallation target for neutron generation in several applications and for tritium generation in fusion systems. In this framework, a new facility named NAtural CIrculation Experiment (NACIE), has been designed at ENEA-Brasimone Research Centre. NACIE is a rectangular loop, made by stainless steel pipes. It consists mainly of a cold and hot leg and an expansion tank installed on the top of the loop. A fuel bundle simulator, made by three electrical heaters placed in a triangular lattice, is located in the lower part of the cold leg, while a tube in tube heat exchanger is installed in the upper part of the hot leg. The adopted secondary fluid is THT oil, while the foreseen primary fluid for the tests is lead-bismuth in eutectic composition (LBE). The aim of the facility is to carry out experimental tests of natural circulation and collect data on the heat transfer coefficient (HTC) for heavy liquid metal flowing through rod bundles. The paper is focused on the preliminary estimation of the LBE flow rate along the loop. An analytical methodology has been applied, solving the continuity, momentum and energy transport equations under appropriate hypothesis. Moreover numerical simulations have been performed. The FLUENT 6.2 CFD code has been utilized for the numerical simulations. The main results carried out from the pre-tests simulations are illustrated in the paper, and a comparison with the theoretical estimations is done.

  15. One-Dimensional, Two-Phase Flow Modeling Toward Interpreting Motor Slag Expulsion Phenomena

    NASA Technical Reports Server (NTRS)

    Kibbey, Timothy P.

    2012-01-01

    Aluminum oxide slag accumulation and expulsion was previously shown to be a player in various solid rocket motor phenomena, including the Space Shuttle's Reusable Solid Rocket Motor (RSRM) pressure perturbation, or "blip," and phantom moment. In the latter case, such un ]commanded side accelerations near the end of burn have also been identified in several other motor systems. However, efforts to estimate the mass expelled during a given event have come up short. Either bulk calculations are performed without enough physics present, or multiphase, multidimensional Computational Fluid Dynamic analyses are performed that give a snapshot in time and space but do not always aid in grasping the general principle. One ]dimensional, two ]phase compressible flow calculations yield an analytical result for nozzle flow under certain assumptions. This can be carried further to relate the bulk motor parameters of pressure, thrust, and mass flow rate under the different exhaust conditions driven by the addition of condensed phase mass flow. An unknown parameter is correlated to airflow testing with water injection where mass flow rates and pressure are known. Comparison is also made to full ]scale static test motor data where thrust and pressure changes are known and similar behavior is shown. The end goal is to be able to include the accumulation and flow of slag in internal ballistics predictions. This will allow better prediction of the tailoff when much slag is ejected and of mass retained versus time, believed to be a contributor to the widely-observed "flight knockdown" parameter.

  16. Maximum group velocity in a one-dimensional model with a sinusoidally varying staggered potential

    NASA Astrophysics Data System (ADS)

    Nag, Tanay; Sen, Diptiman; Dutta, Amit

    2015-06-01

    We use Floquet theory to study the maximum value of the stroboscopic group velocity in a one-dimensional tight-binding model subjected to an on-site staggered potential varying sinusoidally in time. The results obtained by numerically diagonalizing the Floquet operator are analyzed using a variety of analytical schemes. In the low-frequency limit we use adiabatic theory, while in the high-frequency limit the Magnus expansion of the Floquet Hamiltonian turns out to be appropriate. When the magnitude of the staggered potential is much greater or much less than the hopping, we use degenerate Floquet perturbation theory; we find that dynamical localization occurs in the former case when the maximum group velocity vanishes. Finally, starting from an "engineered" initial state where the particles (taken to be hard-core bosons) are localized in one part of the chain, we demonstrate that the existence of a maximum stroboscopic group velocity manifests in a light-cone-like spreading of the particles in real space.

  17. One-dimensional pair hopping and attractive Hubbard models: A comparative study

    SciTech Connect

    van den Bossche, M.; Caffarel, M.

    1996-12-01

    The low-energy physics of the one-dimensional pair hopping (PH) and attractive Hubbard models are expected to be similar. Based on numerical calculations on small chains, several authors have recently challenged this idea and predicted the existence of a phase transition at half filling and finite positive coupling for the pair-hopping model. We reexamine the controversy by making systematic comparisons between numerical results obtained for the PH and attractive Hubbard models. To do so, we have calculated the Luttinger parameters (spin and charge velocities, stiffnesses, etc.) of the two models using both the density matrix renormalization-group method for large systems and Lancz{acute o}s calculations with twisted boundary conditions for smaller systems. Although most of our results confirm that both models are very similar we have found some important differences in the spin properties for the small sizes considered by previous numerical studies (6{endash}12 sites). However, we show that these differences disappear at larger sizes (14{endash}42 sites) when sufficiently accurate eigenstates are considered. Accordingly, our results strongly suggest that the ground-state phase transition previously found for small systems is a finite size artifact. Interpreting our results within the framework of the Luttinger liquid theory, we discuss the origin of the apparent contradiction between the predictions of the perturbative renormalization-group approach and numerical calculations at small sizes. {copyright} {ital 1996 The American Physical Society.}

  18. One-dimensional edge state transport in a topological Kondo insulator

    NASA Astrophysics Data System (ADS)

    Nakajima, Yasuyuki; Syers, Paul; Wang, Xiangfeng; Wang, Renxiong; Paglione, Johnpierre

    2016-03-01

    Topological insulators, with metallic boundary states protected against time-reversal-invariant perturbations, are a promising avenue for realizing exotic quantum states of matter, including various excitations of collective modes predicted in particle physics, such as Majorana fermions and axions. According to theoretical predictions, a topological insulating state can emerge from not only a weakly interacting system with strong spin-orbit coupling, but also in insulators driven by strong electron correlations. The Kondo insulator compound SmB6 is an ideal candidate for realizing this exotic state of matter, with hybridization between itinerant conduction electrons and localized f-electrons driving an insulating gap and metallic surface states at low temperatures. Here we exploit the existence of surface ferromagnetism in SmB6 to investigate the topological nature of metallic surface states by studying magnetotransport properties at very low temperatures. We find evidence of one-dimensional surface transport with a quantized conductance value of e2/h originating from the chiral edge channels of ferromagnetic domain walls, providing strong evidence that topologically non-trivial surface states exist in SmB6.

  19. Energy transport mechanism in the form of proton soliton in a one-dimensional hydrogen-bonded polypeptide chain.

    PubMed

    Kavitha, L; Priya, R; Ayyappan, N; Gopi, D; Jayanthi, S

    2016-01-01

    The dynamics of protons in a one-dimensional hydrogen-bonded (HB) polypeptide chain (PC) is investigated theoretically. A new Hamiltonian is formulated with the inclusion of higher-order molecular interactions between peptide groups (PGs). The wave function of the excitation state of a single particle is replaced by a new wave function of a two-quanta quasi-coherent state. The dynamics is governed by a higher-order nonlinear Schrödinger equation and the energy transport is performed by the proton soliton. A nonlinear multiple-scale perturbation analysis has been performed and the evolution of soliton parameters such as velocity and amplitude is explored numerically. The proton soliton is thermally stable and very robust against these perturbations. The energy transport by the proton soliton is more appropriate to understand the mechanism of energy transfer in biological processes such as muscle contraction, DNA replication, and neuro-electric pulse transfer on biomembranes.

  20. Continuous-Energy Adjoint Flux and Perturbation Calculation using the Iterated Fission Probability Method in Monte Carlo Code TRIPOLI-4® and Underlying Applications

    NASA Astrophysics Data System (ADS)

    Truchet, G.; Leconte, P.; Peneliau, Y.; Santamarina, A.; Malvagi, F.

    2014-06-01

    Pile-oscillation experiments are performed in the MINERVE reactor at the CEA Cadarache to improve nuclear data accuracy. In order to precisely calculate small reactivity variations (<10 pcm) obtained in these experiments, a reference calculation need to be achieved. This calculation may be accomplished using the continuous-energy Monte Carlo code TRIPOLI-4® by using the eigenvalue difference method. This "direct" method has shown limitations in the evaluation of very small reactivity effects because it needs to reach a very small variance associated to the reactivity in both states. To answer this problem, it has been decided to implement the exact perturbation theory in TRIPOLI-4® and, consequently, to calculate a continuous-energy adjoint flux. The Iterated Fission Probability (IFP) method was chosen because it has shown great results in some other Monte Carlo codes. The IFP method uses a forward calculation to compute the adjoint flux, and consequently, it does not rely on complex code modifications but on the physical definition of the adjoint flux as a phase-space neutron importance. In the first part of this paper, the IFP method implemented in TRIPOLI-4® is described. To illustrate the effciency of the method, several adjoint fluxes are calculated and compared with their equivalent obtained by the deterministic code APOLLO-2. The new implementation can calculate angular adjoint flux. In the second part, a procedure to carry out an exact perturbation calculation is described. A single cell benchmark has been used to test the accuracy of the method, compared with the "direct" estimation of the perturbation. Once again the method based on the IFP shows good agreement for a calculation time far more inferior to the "direct" method. The main advantage of the method is that the relative accuracy of the reactivity variation does not depend on the magnitude of the variation itself, which allows us to calculate very small reactivity perturbations with high

  1. One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure

    NASA Technical Reports Server (NTRS)

    Amar, Adam J.; Blackwell, Ben F.; Edwards, Jack R.

    2007-01-01

    The development and verification of a one-dimensional material thermal response code with ablation is presented. The implicit time integrator, control volume finite element spatial discretization, and Newton's method for nonlinear iteration on the entire system of residual equations have been implemented and verified for the thermochemical ablation of internally decomposing materials. This study is a continuation of the work presented in "One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure" (AIAA-2006-2910), which described the derivation, implementation, and verification of the constant density solid energy equation terms and boundary conditions. The present study extends the model to decomposing materials including decomposition kinetics, pyrolysis gas flow through the porous char layer, and a mixture (solid and gas) energy equation. Verification results are presented for the thermochemical ablation of a carbon-phenolic ablator which involves the solution of the entire system of governing equations.

  2. Two-dimensional optical processing using one-dimensional input devices

    NASA Technical Reports Server (NTRS)

    Psaltis, D.

    1984-01-01

    Two-dimensional optical processing architectures that are implemented with one-dimensional input spatial light modulators are reviewed. The advanced state of the art of available one-dimensional devices and the flexibility that exists in the design of two-dimensional architectures with one-dimensional transducers leads to the implementation of the most powerful and versatile optical processors. Signal and image processing architectures of this type are discussed.

  3. Simulation of Thermal Stratification in BWR Suppression Pools with One Dimensional Modeling Method

    SciTech Connect

    Haihua Zhao; Ling Zou; Hongbin Zhang

    2014-01-01

    The suppression pool in a boiling water reactor (BWR) plant not only is the major heat sink within the containment system, but also provides the major emergency cooling water for the reactor core. In several accident scenarios, such as a loss-of-coolant accident and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; the pool temperature distribution also affects the NPSHa (available net positive suction head) and therefore the performance of the Emergency Core Cooling System and Reactor Core Isolation Cooling System pumps that draw cooling water back to the core. Current safety analysis codes use zero dimensional (0-D) lumped parameter models to calculate the energy and mass balance in the pool; therefore, they have large uncertainties in the prediction of scenarios in which stratification and mixing are important. While three-dimensional (3-D) computational fluid dynamics (CFD) methods can be used to analyze realistic 3-D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, resulting in a long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code (Berkeley mechanistic MIXing code in C++) has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by one-dimensional (1-D) transient partial differential equations and substructures (such as free or wall jets) are modeled with 1-D integral models. This allows very large reductions in computational effort compared to multi-dimensional CFD modeling. One heat-up experiment performed at the Finland POOLEX facility, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, is used for

  4. Estimates of error introduced when one-dimensional inverse heat transfer techniques are applied to multi-dimensional problems

    SciTech Connect

    Lopez, C.; Koski, J.A.; Razani, A.

    2000-01-06

    A study of the errors introduced when one-dimensional inverse heat conduction techniques are applied to problems involving two-dimensional heat transfer effects was performed. The geometry used for the study was a cylinder with similar dimensions as a typical container used for the transportation of radioactive materials. The finite element analysis code MSC P/Thermal was used to generate synthetic test data that was then used as input for an inverse heat conduction code. Four different problems were considered including one with uniform flux around the outer surface of the cylinder and three with non-uniform flux applied over 360{degree}, 180{degree}, and 90{degree} sections of the outer surface of the cylinder. The Sandia One-Dimensional Direct and Inverse Thermal (SODDIT) code was used to estimate the surface heat flux of all four cases. The error analysis was performed by comparing the results from SODDIT and the heat flux calculated based on the temperature results obtained from P/Thermal. Results showed an increase in error of the surface heat flux estimates as the applied heat became more localized. For the uniform case, SODDIT provided heat flux estimates with a maximum error of 0.5% whereas for the non-uniform cases, the maximum errors were found to be about 3%, 7%, and 18% for the 360{degree}, 180{degree}, and 90{degree} cases, respectively.

  5. One-dimensional numerical modeling of Blue Jet and its impact on stratospheric chemistry

    NASA Astrophysics Data System (ADS)

    Duruisseau, F.; Thiéblemont, R.; Huret, N.

    2011-12-01

    In the stratosphere the ozone layer is very sensitive to the NOx abundance. The ionisation of N2 and O2 molecules by TLE's (Transient Luminous Events) is a source of NOx which is currently not well quantified and could act as a loss of ozone. In this study a one dimensional explicit parameterization of a Blue-Jet propagation based on that proposed by Raizer et al. (2006 and 2007) has been developed. This parameterization considers Blue-Jet as a streamer initiated by a bidirectional leader discharge, emerging from the anvil and sustained by moderate cloud charge. The streamer growth varies with the electrical field induced by initial cloud charge and the initial altitude. This electrical parameterization and the chemical mechanisms associated with the discharge have been implemented into a detailed chemical model of stratospheric ozone including evolution of nitrogen, chlorine and bromine species. We will present several tests performed to validate the electrical code and evaluate the propagation velocity and the maximum altitude attains by the blue jet as a function of electrical parameters. The results obtained giving the spatiotemporal evolution of the electron density are then used to initiate the specific chemistry associated with the Blue Jet. Preliminary results on the impact of such discharge on the ozone content and the whole stratospheric system will be presented.

  6. Thermal Decomposition of Trinitrotoluene (TNT) with a New One-Dimensional Time to Explosion (ODTX) Apparatus

    SciTech Connect

    Tran, T D; Simpson, R L; Maienschein, J; Tarver, C

    2001-03-23

    The thermal explosion of trinitrotoluene (TNT) is used as a basis for evaluating the performance of a new One-Dimensional-Time-to-Explosion (ODTX) apparatus. The ODTX experiment involves holding a 12.7 mm-diameter spherical explosive sample under confinement (150 MPa) at a constant elevated temperature until the confining pressure is exceeded by the evolution of gases during chemical decomposition. The resulting time to explosion as a function of temperature provides valuable decomposition kinetic information. A comparative analysis of the measurements obtained from the new unit and an older system is presented. Discussion on selected performance aspects of the new unit will also be presented. The thermal explosion of TNT is highly dependent on the material. Analysis of the time to explosion is complicated by historical and experimental factors such as material variability, sample preparation, temperature measurement and system errors. Many of these factors will be addressed. Finally, a kinetic model using a coupled thermal and heat transport code (chemical TOPAZ) was used to match the experimental data.

  7. An adaptive mesh-moving and refinement procedure for one-dimensional conservation laws

    NASA Technical Reports Server (NTRS)

    Biswas, Rupak; Flaherty, Joseph E.; Arney, David C.

    1993-01-01

    We examine the performance of an adaptive mesh-moving and /or local mesh refinement procedure for the finite difference solution of one-dimensional hyperbolic systems of conservation laws. Adaptive motion of a base mesh is designed to isolate spatially distinct phenomena, and recursive local refinement of the time step and cells of the stationary or moving base mesh is performed in regions where a refinement indicator exceeds a prescribed tolerance. These adaptive procedures are incorporated into a computer code that includes a MacCormack finite difference scheme wih Davis' artificial viscosity model and a discretization error estimate based on Richardson's extrapolation. Experiments are conducted on three problems in order to qualify the advantages of adaptive techniques relative to uniform mesh computations and the relative benefits of mesh moving and refinement. Key results indicate that local mesh refinement, with and without mesh moving, can provide reliable solutions at much lower computational cost than possible on uniform meshes; that mesh motion can be used to improve the results of uniform mesh solutions for a modest computational effort; that the cost of managing the tree data structure associated with refinement is small; and that a combination of mesh motion and refinement reliably produces solutions for the least cost per unit accuracy.

  8. One-dimensional model of the equiaxed grain formation in multi-crystalline silicon

    NASA Astrophysics Data System (ADS)

    Beaudhuin, M.; Duffar, T.; Lemiti, M.; Zaidat, K.

    2011-03-01

    During solidification of low purity silicon for photovoltaic (PV) cells, solute rejection at the growth interface leads to an increase of the carbon concentration in the liquid phase and then to the precipitation of silicon carbide (SiC). When the precipitate radius becomes higher than the silicon critical nucleus radius, SiC can act as a refining agent for the Si and Si equiaxed grains appear in the liquid. The grain structure of the ingot changes from columnar to small grains, also known as grits. We developed a one-dimensional analytical model of this series of phenomena, including C segregation, SiC nucleation and growth, Si nucleation on the SiC precipitates and subsequent growth of the Si equiaxed grains. The equations are implemented under Matlab software in order to predict the columnar to equiaxed transition (CET) during the directional solidification of PV Si. We carried out calculations of the position and thickness of the equiaxed areas and of the number and size of Si grits as a function of the main process parameters: thermal gradient and growth velocity. Recommendations in order to adapt the growth process parameters to the initial carbon content are given. It is expected that coupling this model to global 3D numerical simulation codes could help improving the yield of ingot solidification.

  9. EFDC1D - A ONE DIMENSIONAL HYDRODYNAMIC AND SEDIMENT TRANSPORT MODEL FOR RIVER AND STREAM NETWORKS: MODEL THEORY AND USERS GUIDE

    EPA Science Inventory

    This technical report describes the new one-dimensional (1D) hydrodynamic and sediment transport model EFDC1D. This model that can be applied to stream networks. The model code and two sample data sets are included on the distribution CD. EFDC1D can simulate bi-directional unstea...

  10. One-dimensional frustrated plaquette compass model: Nematic phase and spontaneous multimerization

    NASA Astrophysics Data System (ADS)

    Brzezicki, Wojciech; Oleś, Andrzej M.

    2016-06-01

    We introduce a one-dimensional (1D) pseudospin model on a ladder where the Ising interactions along the legs and along the rungs alternate between XiXi +1 and ZiZi +1 for even/odd bond (rung). We include also the next-nearest-neighbor Ising interactions on plaquettes' diagonals that alternate in such a way that a model where only leg interactions are switched on is equivalent to the one when only the diagonal ones are present. Thus in the absence of rung interactions the model can interpolate between two 1D compass models. The model possesses local symmetries which are the parities within each 2 ×2 cell (plaquette) of the ladder. We find that for different values of the interaction it can realize ground states that differ by the patterns formed by these local parities. By exact diagonalization we derive detailed phase diagrams for small systems of L =4 , 6, and 8 plaquettes, and use next L =12 to identify generic phases that appear in larger systems as well. Among them we find a nematic phase with macroscopic degeneracy when the leg and diagonal interactions are equal and the rung interactions are larger than a critical value. By performing a perturbative expansion around this phase we find indeed a very complex competition around the nematic phase which has to do with releasing frustration in this range of parameters. The nematic phase is similar to the one found in the two-dimensional compass model. For particular parameters the low-energy sector of the present plaquette model reduces to a 1D compass model with spins S =1 which suggests that it realizes peculiar crossovers within the class of compass models. Finally, we show that the model can realize phases with broken translation invariance which can be either dimerized, trimerized, etc., or completely disordered and highly entangled in a well identified window of the phase diagram.

  11. One-Dimensional Analysis of Thermal Stratification in AHTR and SFR Coolant Pools

    SciTech Connect

    Haihua Zhao; Per F. Peterson

    2007-10-01

    Thermal stratification phenomena are very common in pool type reactor systems, such as the liquid-salt cooled Advanced High Temperature Reactor (AHTR) and liquid-metal cooled fast reactor systems such as the Sodium Fast Reactor (SFR). It is important to accurately predict the temperature and density distributions both for design optimation and accident analysis. Current major reactor system analysis codes such as RELAP5 (for LWR’s, and recently extended to analyze high temperature reactors), TRAC (for LWR’s), and SASSYS (for liquid metal fast reactors) only provide lumped-volume based models which can only give very approximate results and can only handle simple cases with one mixing source. While 2-D or 3-D CFD methods can be used to analyze simple configurations, these methods require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, yet such fine grid resolution is difficult or impossible to provide for studying the reactor response to transients due to computational expense. Therefore, new methods are needed to support design optimization and safety analysis of Generation IV pool type reactor systems. Previous scaling has shown that stratified mixing processes in large stably stratified enclosures can be described using one-dimensional differential equations, with the vertical transport by free and wall jets modeled using standard integral techniques. This allows very large reductions in computational effort compared to three-dimensional numerical modeling of turbulent mixing in large enclosures. The BMIX++ (Berkeley mechanistic MIXing code in C++) code was originally developed at UC Berkeley to implement such ideas. This code solves mixing and heat transfer problems in stably stratified enclosures. The code uses a Lagrangian approach to solve 1-D transient governing equations for the ambient fluid and uses analytical or 1-D integral models to compute substructures. By including liquid salt properties, BMIX++ code is

  12. One-Dimensional Perovskite Manganite Oxide Nanostructures: Recent Developments in Synthesis, Characterization, Transport Properties, and Applications

    NASA Astrophysics Data System (ADS)

    Li, Lei; Liang, Lizhi; Wu, Heng; Zhu, Xinhua

    2016-03-01

    One-dimensional nanostructures, including nanowires, nanorods, nanotubes, nanofibers, and nanobelts, have promising applications in mesoscopic physics and nanoscale devices. In contrast to other nanostructures, one-dimensional nanostructures can provide unique advantages in investigating the size and dimensionality dependence of the materials' physical properties, such as electrical, thermal, and mechanical performances, and in constructing nanoscale electronic and optoelectronic devices. Among the one-dimensional nanostructures, one-dimensional perovskite manganite nanostructures have been received much attention due to their unusual electron transport and magnetic properties, which are indispensable for the applications in microelectronic, magnetic, and spintronic devices. In the past two decades, much effort has been made to synthesize and characterize one-dimensional perovskite manganite nanostructures in the forms of nanorods, nanowires, nanotubes, and nanobelts. Various physical and chemical deposition techniques and growth mechanisms are explored and developed to control the morphology, identical shape, uniform size, crystalline structure, defects, and homogenous stoichiometry of the one-dimensional perovskite manganite nanostructures. This article provides a comprehensive review of the state-of-the-art research activities that focus on the rational synthesis, structural characterization, fundamental properties, and unique applications of one-dimensional perovskite manganite nanostructures in nanotechnology. It begins with the rational synthesis of one-dimensional perovskite manganite nanostructures and then summarizes their structural characterizations. Fundamental physical properties of one-dimensional perovskite manganite nanostructures are also highlighted, and a range of unique applications in information storages, field-effect transistors, and spintronic devices are discussed. Finally, we conclude this review with some perspectives/outlook and future

  13. One-dimensional vibrational excitons in 1,2,4,5-tetrachlorobenzene

    NASA Astrophysics Data System (ADS)

    Abramson, E. H.; Jongenelis, A. P. J. M.; Schmidt, J.

    1987-10-01

    We have studied the line shapes of vibronic transitions in the phosphorescence spectrum of the one-dimensional triplet exciton of TCB between 4.2 and 0.4 K. It is shown that also the vibrational excitons are highly one dimensional. This finding is confirmed by time-resolved emission spectra. Observed vibron bandwidths vary up to 15 cm-1 with k=0 either at the top or at the bottom of the band. In contrast to the fundamental vibrations, no overtones or combination bands give evidence of a well-defined one-dimensional quasimomentum.

  14. Comment on "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit"

    NASA Astrophysics Data System (ADS)

    Carrillo-Bernal, M. A.; Núñez-Yépez, H. N.; Salas-Brito, A. L.; Solis, Didier A.

    2015-02-01

    In the referred paper, the authors use a numerical method for solving ordinary differential equations and a softened Coulomb potential -1 /√{x2+β2 } to study the one-dimensional Coulomb problem by approaching the parameter β to zero. We note that even though their numerical findings in the soft potential scenario are correct, their conclusions do not extend to the one-dimensional Coulomb problem (β =0 ). Their claims regarding the possible existence of an even ground state with energy -∞ with a Dirac-δ eigenfunction and of well-defined parity eigenfunctions in the one-dimensional hydrogen atom are questioned.

  15. Photocatalytic activity of silver vanadate with one-dimensional structure under fluorescent light.

    PubMed

    Ren, Jia; Wang, Wenzhong; Shang, Meng; Sun, Songmei; Zhang, Ling; Chang, Jiang

    2010-11-15

    One-dimensional β-AgVO(3) nanobelts (SVN) were realized by a facile hydrothermal method. It indicates the anisotropic crystallographic characteristics through the characterization. With the additive PEG, the sample was restrained in the one-dimensional preferential orientation (SV-P) effectively. The photocatalytic activity studies reveal that the photocatalyst β-AgVO(3) exhibits excellent photocatalytic activity in the inactivation of Escherichia coli under fluorescent light. In addition, it is found that the morphology has effect on the photocatalytic activity. The β-AgVO(3) photocatalyst with one-dimensional structure has the potential and promising application in bacterial disinfection indoor using fluorescent light. PMID:20800352

  16. A one-dimensional study of the evolution of the microwave breakdown in air

    SciTech Connect

    Semenov, V. E.; Rakova, E. I.; Glyavin, M. Yu.; Tarakanov, V. P.; Nusinovich, G. S.

    2015-09-15

    The microwave breakdown in air is simulated numerically within a simple 1D model taking into account a perturbation of electromagnetic field by plasma. The simulations were performed using two qualitatively different codes. One of these codes is based on computation of Maxwell equations, whereas the other one utilizes an approximation of quasi-monochromatic electromagnetic field. There is a good agreement between simulation results obtained by using both codes. Calculations have been carried out in a wide range of air pressures and field frequencies; also varied were initial spatial distributions of plasma density. The results reveal strong dependence of the breakdown evolution on the relation between the field frequency and the gas pressure as well as on the presence of extended rarefied background plasma. At relatively low gas pressures (or high field frequencies), the breakdown process is accompanied by the stationary ionization wave propagating towards the incident electromagnetic wave. In the case of a high gas pressure (or a relatively low field frequency), the peculiarities of the breakdown are associated with a formation of plasma filament array. The extended background plasma can suppress formation of the plasma filament array completely even at high pressures (or low frequencies)

  17. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    NASA Astrophysics Data System (ADS)

    da Costa, Diogo Ricardo; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

    2016-04-01

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems.

  18. Global classical solutions to the one-dimensional compressible fluid models of Korteweg type with large initial data

    NASA Astrophysics Data System (ADS)

    Chen, Zhengzheng; Chai, Xiaojuan; Dong, Boqing; Zhao, Huijiang

    2015-10-01

    This paper is concerned with the global existence of classical solutions with large initial data away from vacuum to the Cauchy problem of the one-dimensional isothermal compressible fluid models of Korteweg type with density-dependent viscosity coefficient and capillarity coefficient. The case when the viscosity coefficient μ (ρ) =ρα and the capillarity coefficient κ (ρ) =ρβ for some parameters α, β ∈ R is considered. Under some conditions on α, β, we first show the global existence of large solutions around constant states if the far-fields of the initial data are the same, while if the far-fields of the initial data are different, we prove the global stability of rarefaction waves with large strength. Here global stability means the initial perturbation can be arbitrarily large. Our analysis is based on the elementary energy method and the technique developed by Y. Kanel' [29].

  19. Brownian-dynamics computer simulations of a one-dimensional polymer model. I. Simple potentials

    SciTech Connect

    Cook, R.; Livornese, L.L.

    1982-11-01

    Brownian Dynamics computer simulation results are presented on a simple one-dimensional polymer model which contains the essential features of rotational angle flexibility. Comparison is made with analytical treatments of the model.

  20. Simulating higher-dimensional geometries in GADRAS using approximate one-dimensional solutions.

    SciTech Connect

    Thoreson, Gregory G.; Mitchell, Dean J; Harding, Lee T.

    2013-02-01

    The Gamma Detector Response and Analysis Software (GADRAS) software package is capable of simulating the radiation transport physics for one-dimensional models. Spherical shells are naturally one-dimensional, and have been the focus of development and benchmarking. However, some objects are not spherical in shape, such as cylinders and boxes. These are not one-dimensional. Simulating the radiation transport in two or three dimensions is unattractive because of the extra computation time required. To maintain computational efficiency, higher-dimensional geometries require approximations to simulate them in one-dimension. This report summarizes the theory behind these approximations, tests the theory against other simulations, and compares the results to experimental data. Based on the results, it is recommended that GADRAS users always attempt to approximate reality using spherical shells. However, if fissile material is present, it is imperative that the shape of the one-dimensional model matches the fissile material, including the use of slab and cylinder geometry.

  1. Demonstration of one-dimensional quantum random walks using orbital angular momentum of photons

    SciTech Connect

    Zhang, Pei; Ren, Xi-Feng; Zou, Xu-Bo; Liu, Bi-Heng; Huang, Yun-Feng; Guo, Guang-Can

    2007-05-15

    Quantum random walks have attracted special interest because they could lead to new quantum algorithms. Photons can carry orbital angular momentum (OAM) thereby offering a practical realization of a high-dimensional quantum information carrier. By employing OAM of photons, we experimentally realized the one-dimensional discrete-time quantum random walk. Three steps of a one-dimensional quantum random walk were implemented in our protocol showing the obvious difference between quantum and classical random walks.

  2. One-Dimensional Hybrid Satellite Track Model for the Dynamics Explorer 2 (DE 2) Satellite

    NASA Technical Reports Server (NTRS)

    Deng, Wei; Killeen, T. L.; Burns, A. G.; Johnson, R. M.; Emery, B. A.; Roble, R. G.; Winningham, J. D.; Gary, J. B.

    1995-01-01

    A one-dimensional hybrid satellite track model has been developed to calculate the high-latitude thermospheric/ionospheric structure below the satellite altitude using Dynamics Explorer 2 (DE 2) satellite measurements and theory. This model is based on Emery et al. satellite track code but also includes elements of Roble et al. global mean thermosphere/ionosphere model. A number of parameterizations and data handling techniques are used to input satellite data from several DE 2 instruments into this model. Profiles of neutral atmospheric densities are determined from the MSIS-90 model and measured neutral temperatures. Measured electron precipitation spectra are used in an auroral model to calculate particle impact ionization rates below the satellite. These rates are combined with a solar ionization rate profile and used to solve the O(+) diffusion equation, with the measured electron density as an upper boundary condition. The calculated O(+) density distribution, as well as the ionization profiles, are then used in a photochemical equilibrium model to calculate the electron and molecular ion densities. The electron temperature is also calculated by solving the electron energy equation with an upper boundary condition determined by the DE 2 measurement. The model enables calculations of altitude profiles of conductivity and Joule beating rate along and below the satellite track. In a first application of the new model, a study is made of thermospheric and ionospheric structure below the DE 2 satellite for a single orbit which occurred on October 25, 1981. The field-aligned Poynting flux, which is independently obtained for this orbit, is compared with the model predictions of the height-integrated energy conversion rate. Good quantitative agreement between these two estimates has been reached. In addition, measurements taken at the incoherent scatter radar site at Chatanika (65.1 deg N, 147.4 deg W) during a DE 2 overflight are compared with the model

  3. Displacement correlation as an indicator of collective motion in one-dimensional and quasi-one-dimensional systems of repulsive Brownian particles

    NASA Astrophysics Data System (ADS)

    Ooshida, Takeshi; Goto, Susumu; Matsumoto, Takeshi; Otsuki, Michio

    2015-12-01

    While the slow dynamics in glassy liquids are known to be accompanied by collective motions undetectable with static structure factor and requiring four-point space-time correlations for their detection, it is usually difficult to calculate such correlations analytically. In the present study, a system of Brownian particles in a (quasi-)one-dimensional passageway is taken as an example to demonstrate the usefulness of displacement correlation. In the purely one-dimensional case (known as the single-file diffusion) with overtaking forbidden, the diffusion slows down and collective motion is captured by displacement correlation both calculated here numerically and analytically. On the other hand, displacement correlation vanishes if overtaking is allowed, which leads to normal diffusion.

  4. Some recent applications of XTRAN3S. [time marching finite difference code for solution of three-dimensional transonic small perturbation flow

    NASA Technical Reports Server (NTRS)

    Seidel, D. A.; Bennett, R. M.; Ricketts, R. H.

    1983-01-01

    A time-marching finite difference code, XTRAN3S, that solves the three-dimensional transonic small perturbation equation for flow over isolated wings has recently been developed. During initial applications of the program, problems were encountered in the prediction of unsteady forces. The use of a revised grid and force calculation scheme improved those predictions. Comparisons are made between predicted and experimental pressure data for a rectangular supercritical wing. Comparisons of steady and unsteady data at freestream Mach number = 0.700 show good agreement between calculated and experimental values. A comparison of steady data at freestream Mach number = 0.825 shows poor agreement between calculations and experiment. Program difficulties have been encountered with swept and tapered configurations.

  5. The parallel implementation of the one-dimensional Fourier transformed Vlasov Poisson system

    NASA Astrophysics Data System (ADS)

    Eliasson, Bengt

    2005-08-01

    A parallel implementation of an algorithm for solving the one-dimensional, Fourier transformed Vlasov-Poisson system of equations is documented, together with the code structure, file formats and settings to run the code. The properties of the Fourier transformed Vlasov-Poisson system is discussed in connection with the numerical solution of the system. The Fourier method in velocity space is used to treat numerical problems arising due the filamentation of the solution in velocity space. Outflow boundary conditions in the Fourier transformed velocity space removes the highest oscillations in velocity space. A fourth-order compact Padé scheme is used to calculate derivatives in the Fourier transformed velocity space, and spatial derivatives are calculated with a pseudo-spectral method. The parallel algorithms used are described in more detail, in particular the parallel solver of the tri-diagonal systems occurring in the Padé scheme. Program summaryTitle of program:vlasov Catalogue identifier:ADVQ Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVQ Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Operating system under which the program has been tested: Sun Solaris; HP-UX; Read Hat Linux Programming language used: FORTRAN 90 with Message Passing Interface (MPI) Computers: Sun Ultra Sparc; HP 9000/785; HP IPF (Itanium Processor Family) ia64 Cluster; PCs cluster Number of lines in distributed program, including test data, etc.:3737 Number of bytes in distributed program, including test data, etc.:18 772 Distribution format: tar.gz Nature of physical problem: Kinetic simulations of collisionless electron-ion plasmas. Method of solution: A Fourier method in velocity space, a pseudo-spectral method in space and a fourth-order Runge-Kutta scheme in time. Memory required to execute with typical data: Uses typically of the order 10 5-10 6 double precision numbers. Restriction on the complexity of the problem: The program uses

  6. Interacting one dimensional electron systems and stripe phase of high temperature superconductors

    NASA Astrophysics Data System (ADS)

    Jaefari, Akbar

    In this dissertation, I will consider the problem of coupled one dimensional electronic systems particularly in connection with the stripe phases of high temperature superconductors. Three major problems have been addressed in this dissertation. In chapter one, I consider the problem of the Local Density of States for spin-gapped one-dimensional charge density wave (CDW) states and Mott insulators in the presence of a hard-wall boundary. I calculate the boundary contribution to the single-particle Green function in the low-energy limit using field theory techniques and analyze it in terms of its Fourier transform in both time and space. The boundary LDOS in the CDW case exhibits a singularity at momentum 2kF, which is indicative of the pinning of the CDW order at the impurity. Several dispersing features has been observed at frequencies above the spin gap, which provide a characteristic signature of spin-charge separation. This demonstrates that the boundary LDOS can be used to infer properties of the underlying bulk system. In the presence of a boundary magnetic field mid-gap states localized at the boundary emerge with signature in the LDOS. I discuss implications of these results for STM experiments on quasi-1D systems such as two-leg ladder materials like Sr14Cu24O41. By exchanging the roles of charge and spin sectors, all our results directly carry over to the case of one-dimensional Mott insulators. In the second chapter, I study an extended Hubbard-Heisenberg model on two types of two leg ladders, a model without flux and a model with flux pi per plaquette. In the case of the conventional (flux-less) ladder the Pair density wave state arises for certain filling fractions when commensurability conditions is satisfied. For the flux pi ladder the pair density wave phase is generally present. The PDW phase is characterized by a finite spin gap and a superconducting order parameter with a finite (commensurate in this case) wave vector and power

  7. One-dimensional and two-dimensional arrays of nanoholes generated by laser in the semiconfined configuration

    NASA Astrophysics Data System (ADS)

    Lugomer, S.; Maksimović, A.; Peto, G.; Toth, A.; Horvath, E.

    2006-11-01

    We have shown that nanoporosity can be generated on metal surfaces by nanosecond laser-matter interactions in the semiconfined configuration. The scanning electron microscope analysis has shown that nanoholes of ˜25-50nm in diameter, arranged in one-dimensional (1D) and two-dimensional (2D) irregular and regular arrays, have been formed. The interpretation is based on the generation of a dispersive, dissipative system of nonlinear solitary plasma waves (humps) that leave temperature/pressure fingerprints on the metal surface. It has been shown that the 1D irregular array of nanoholes can be interpreted as a result of the irregular string of solitary humps obtained by numerical simulation based on the Benney pd equation with the Gaussian perturbation. The 2D random array of nanoholes can be interpreted as a result of random solitary humps that can be obtained by numerical simulation from the Benney equation with the periodic perturbation. The regular string of nanoholes has been shown to appear as a result of breather modes (bound state of solitons), the numerical simulation of which has been based on the Boussinesq equation. The regular 2D array of nanoholes has been interpreted as fingerprints of breather modes, in agreement with the result of the numerical simulation of Tajiri and Murakami, [J. Math. Phys. 34, 2400 (1993)], based on the Kadomtsev-Petviashvili equation.

  8. Spin-triplet superconductivity in a weak-coupling Hubbard model for the quasi-one-dimensional compound Li0.9Mo6O17

    NASA Astrophysics Data System (ADS)

    Cho, Weejee; Platt, Christian; McKenzie, Ross H.; Raghu, Srinivas

    2015-10-01

    The purple bronze Li0.9Mo6O17 is of interest due to its quasi-one-dimensional electronic structure and the possible Luttinger liquid behavior resulting from it. For sufficiently low temperatures, it is a superconductor with a pairing symmetry that is still to be determined. To shed light on this issue, we analyze a minimal Hubbard model for this material involving four molybdenum orbitals per unit cell near quarter filling, using asymptotically exact perturbative renormalization group methods. We find that spin-triplet odd-parity superconductivity is the dominant instability. Approximate nesting properties of the two quasi-one-dimensional Fermi surfaces enhance certain second-order processes, which play crucial roles in determining the structure of the pairing gap. Notably, we find that the gap has more sign changes than required by the point-group symmetry.

  9. Spin triplet superconductivity in a weak-coupling Hubbard model for the quasi-one-dimensional compound Li0.9 Mo6 O17

    NASA Astrophysics Data System (ADS)

    Platt, Christian; Cho, Weejee; McKenzie, Ross H.; Raghu, Sri

    The purple bronze Li0.9Mo6O17 is of interest due to its quasi-one-dimensional electronic structure and the possible Luttinger liquid behavior resulting from it. For sufficiently low temperatures, it is a superconductor with a pairing symmetry that is still to be determined. To shed light on this issue, we analyze a minimal Hubbard model for this material involving four Molybdenum orbitals per unit cell near quarter filling, using asymptotically exact perturbative renormalization group methods. We find that spin triplet odd-parity superconductivity is the dominant instability. Approximate nesting properties of the two quasi-one-dimensional Fermi surfaces enhance certain second-order processes, which play crucial roles in determining the structure of the pairing gap. Notably, we find that the gap has accidental nodes, i.e. it has more sign changes than required by the point-group symmetry.

  10. One-dimensional electromagnetic band gap structures formed by discharge plasmas in a waveguide

    SciTech Connect

    Arkhipenko, V. I.; Simonchik, L. V. Usachonak, M. S.; Callegari, Th.; Sokoloff, J.

    2014-09-28

    We demonstrate the ability to develop one-dimensional electromagnetic band gap structure in X-band waveguide solely by using the positive columns of glow discharges in neon at the middle pressure. Plasma inhomogeneities are distributed uniformly along a typical X-band waveguide with cross section of 23×10 mm². It is shown that electron densities larger than 10¹⁴ cm ⁻³ are needed in order to create an effective one-dimensional electromagnetic band gap structure. Some applications for using the one-dimensional electromagnetic band gap structure in waveguide as a control of microwave (broadband filter and device for variation of pulse duration) are demonstrated.

  11. Superfluid, solid, and supersolid phases of dipolar bosons in a quasi-one-dimensional optical lattice

    SciTech Connect

    Fellows, Jonathan M.; Carr, Sam T.

    2011-11-15

    We discuss a model of dipolar bosons trapped in a weakly coupled planar array of one-dimensional tubes. We consider the situation where the dipolar moments are aligned by an external field, and we find a rich phase diagram as a function of the angle of this field exhibiting quantum phase transitions between solid, superfluid, and supersolid phases. In the low energy limit, the model turns out to be identical to one describing quasi-one-dimensional superconductivity in condensed matter systems. This opens the possibility of using bosons as a quantum analog simulator of electronic systems, a scenario arising from the intricate relation between statistics and interactions in quasi-one-dimensional systems.

  12. Visualizing One-Dimensional Electronic States and their Scattering in Semi-conducting Nanowires

    NASA Astrophysics Data System (ADS)

    Beidenkopf, Haim; Reiner, Jonathan; Norris, Andrew; Nayak, Abhay Kumar; Avraham, Nurit; Shtrikman, Hadas

    One-dimensional electronic systems constitute a fascinating playground for the emergence of exotic electronic effects and phases, within and beyond the Tomonaga-Luttinger liquid paradigm. More recently topological superconductivity and Majorana modes were added to that long list of phenomena. We report scanning tunneling microscopy and spectroscopy measurements conducted on pristine, epitaxialy grown InAs nanowires. We resolve the 1D electronic band structure manifested both via Van-Hove singularities in the local density-of-states, as well as by the quasi-particle interference patterns, induced by scattering from surface impurities. By studying the scattering of the one-dimensional electronic states off various scatterers, including crystallographic defects and the nanowire end, we identify new one-dimensional relaxation regimes and yet unexplored effects of interactions. Some of these may bear implications on the topological superconducting state and Majorana modes therein. The authors acknowledge support from the Israeli Science Foundation (ISF).

  13. One-dimensional light localization with classical scatterers: An advanced undergraduate laboratory experiment

    NASA Astrophysics Data System (ADS)

    Kemp, K. J.; Barker, S.; Guthrie, J.; Hagood, B.; Havey, M. D.

    2016-10-01

    The phenomenon of electronic wave localization through disorder remains an important area of fundamental and applied research. Localization of all wave phenomena, including light, is thought to exist in a restricted one-dimensional geometry. We present here a series of experiments to illustrate, using a straightforward experimental arrangement and approach, the localization of light in a quasi-one-dimensional physical system. In the experiments, reflected and transmitted light from a stack of glass slides of varying thickness reveals an Ohm's law type behavior for small thicknesses, and evolution to exponential decay of the transmitted power for larger thicknesses. For larger stacks of slides, a weak departure from one-dimensional behavior is also observed. The experiment and analysis of the results, showing many of the essential features of wave localization, is relatively straightforward, economical, and suitable for laboratory experiments at an undergraduate level.

  14. Distributed strain measurement system in one-dimensional by means of multipoint FBG sensing

    NASA Astrophysics Data System (ADS)

    Yin, Hao; Zhu, Jun; Tang, Haiyu; Wang, Hui; Zhang, Zhao; Shui, Tao; Yu, Benli

    2013-12-01

    In this paper, we described a distributed strain measurement scheme in one-dimensional. The sensing information of FBG is demodulated by a CCD spectrometer, the discrete strain is achieved by fitting and processing discrete signal demodulated utilizing labVIEW virtual instrument technology. Then it could be achieved by Using polynomial fitting method to one-dimensional discrete strain distributed detection. Experimentally, measurement was implemented in Cantilever to prove the system performance. The experimental result shows that the system can reflect the strain distribution in one-dimensional and an order strain modal characteristics of cantilever accurately. The detection system can achieve real-time and dynamic measurements, the response time for 2kHz, the response accuracy for 4μɛ.

  15. Dynamic simulation of wavy-stratified two-phase flow with the one-dimensional two-fluid model

    NASA Astrophysics Data System (ADS)

    Fullmer, William D.

    The one-dimensional two-fluid model is the basis for the description of the transport of mass, momentum and energy in the thermal-hydraulic codes used for nuclear reactor safety analysis. Unlike other physical transport models, the one-dimensional two-fluid model suffers from the possibility of being ill-posed as an initial-boundary value problem depending on the flow conditions and the relevant physical closure laws. Typically, the ill-posedness is dealt with through either excessive numerical damping or the addition of unphysical closure laws designed for the sole purpose of hyperbolization. Unfortunately both methods eliminate the instability along with the problem of ill-posedness causing the model to undoubtedly lose some of its inherent dynamic capability. In this work, a one-dimensional two-fluid model for horizontal or slightly inclined stratified flow is developed. Higher order physical models that are often neglected, such as surface tension and axial viscous stress, are retained for their short-wavelength stability properties. Characteristic, dispersion and nonlinear analyses are performed to demonstrate that the resulting model is linearly well-posed and nonlinearly well-behaved. While it has been known that higher-order differential terms are able to regularize the short-wavelength problem of ill-posedness without removing the long-wavelength instability, the literature is relatively silent on the consequences of using a model under linearly unstable conditions. Using carefully selected conditions in an idealized infinite domain, it is demonstrated for the first time that the one-dimensional two-fluid model exhibits chaotic behavior in addition to limit cycles and asymptotic stability. The chaotic behavior is a consequence of the long-wavelength linear instability (energy source) the nonlinearity (energy transfer) and the short-wavelength dissipation (energy sink). Since the model is chaotic, solutions exhibit a sensitive dependence on initial

  16. Decoherence and relaxation of a single electron in a one-dimensional conductor

    NASA Astrophysics Data System (ADS)

    Marguerite, A.; Cabart, C.; Wahl, C.; Roussel, B.; Freulon, V.; Ferraro, D.; Grenier, Ch.; Berroir, J.-M.; Plaçais, B.; Jonckheere, T.; Rech, J.; Martin, T.; Degiovanni, P.; Cavanna, A.; Jin, Y.; Fève, G.

    2016-09-01

    We study the decoherence and relaxation of a single elementary electronic excitation propagating in a one-dimensional chiral conductor. Using two-particle interferences in the electronic analog of the Hong-Ou-Mandel experiment, we analyze quantitatively the decoherence scenario of a single electron propagating along a quantum Hall edge channel at filling factor 2. The decoherence results from the emergence of collective neutral excitations induced by Coulomb interaction and leading, in one dimension, to the destruction of the elementary quasiparticle. This study establishes the relevance of electron quantum optics setups to provide stringent tests of strong interaction effects in one-dimensional conductors described by the Luttinger liquids paradigm.

  17. The ion implantation-induced properties of one-dimensional nanomaterials

    PubMed Central

    2013-01-01

    Nowadays, ion implantation is an extensively used technique for material modification. Using this method, we can tailor the properties of target materials, including morphological, mechanical, electronic, and optical properties. All of these modifications impel nanomaterials to be a more useful application to fabricate more high-performance nanomaterial-based devices. Ion implantation is an accurate and controlled doping method for one-dimensional nanomaterials. In this article, we review recent research on ion implantation-induced effects in one-dimensional nanostructure, such as nanowires, nanotubes, and nanobelts. In addition, the optical property of single cadmium sulfide nanobelt implanted by N+ ions has been researched. PMID:23594476

  18. Generalized space-charge limited current and virtual cathode behaviors in one-dimensional drift space

    SciTech Connect

    Yang, Zhanfeng; Liu, Guozhi; Shao, Hao; Chen, Changhua; Sun, Jun

    2013-10-15

    This paper reports the space-charge limited current (SLC) and virtual cathode behaviors in one-dimensional grounded drift space. A simple general analytical solution and an approximate solution for the planar diode are given. Through a semi-analytical method, a general solution for SLC in one-dimensional drift space is obtained. The behaviors of virtual cathode in the drift space, including dominant frequency, electron transit time, position, and transmitted current, are yielded analytically. The relationship between the frequency of the virtual cathode oscillation and the injected current presented may explain previously reported numerical works. Results are significant in facilitating estimations and further analytical studies.

  19. Fabrication, device assembly, and application of one-dimensional chalcogenides nanostructures

    NASA Astrophysics Data System (ADS)

    Kum, Maxwell Chun Man

    Nanotechnology has received a tremendous amount of research interests ever since the first discovery of carbon nanotubes. One-dimensional nanostructures, such as nanorods, nanowires, nanobelts as well as nanotubes, are of significant interest because of their potential application as interconnects and functional units in nanoscale electrical, optoelectronic, electrochemical, electromechanical, thermoelectric, spintronic, photovoltaic, and sensory devices. Nanoscale one-dimensional devices promise to deliver improved performance, to miniaturize bulky devices, to enable higher density nanoscale devices, and to lower energy consumption. As the radius of these one-dimensional nanostructures fall below the exciton Bohr radius of their respective materials, the structural morphology and size effectively modulates the fundamental electrical, optical, and magnetic properties due to quantum confinement effect. In addition, the high surface to volume ratio of one-dimensional nanostructures enables the device properties to be extremely sensitivity to the environment which is particularly attractive for sensing application. Currently, the focuses of nanotechnology research are (1) the fabrication technique with control over the composition, crystal structure, morphology, and size, (2) the device assembly of nanostructures into complex functional devices, and (3) the characterization and application of these nanoscale devices. There are a multitude of fabrication techniques for one-dimensional nanostructures, including but not exclusively, vapor-solid, vapor-liquid-solid, colloidal, solution-liquid-solid, self-assembly, and template directed electrodeposition. As one-dimensional nanostructures are produced, several techniques are available to assemble them into functional complex nanoscale devices, including but not exclusively, electron beam lithography, focus ion beam, magnetic assembly, and AC dielectrophoretic alignment. In this work, one-dimensional cadmium telluride (Cd

  20. The estimation of biological tissues trauma under their perforation by one-dimensional implants

    NASA Astrophysics Data System (ADS)

    Shil'ko, S.; Chernous, D.; Panin, S.

    2015-11-01

    The subject of paper is a base stage of positioning of one-dimensional implants (fixing, diagnostic) element, stretching through an aperture in a biotissue. Corresponding mechanical and mathematical model describes implant interaction with biotissues in the conditions of sticking and sliding of contacting surfaces. Theoretical dependences for implant elongation and the maximum value of stress tensor intensity in interfacing volumes of the material are presented, allowing one to calculate the frictional and mechanical characteristics of one-dimensional implant and to estimate the injuring action from biomechanics point of view.

  1. Fluctuations and Stochastic Processes in One-Dimensional Many-Body Quantum Systems

    SciTech Connect

    Stimming, H.-P.; Mauser, N. J.; Mazets, I. E.

    2010-07-02

    We study the fluctuation properties of a one-dimensional many-body quantum system composed of interacting bosons and investigate the regimes where quantum noise or, respectively, thermal excitations are dominant. For the latter, we develop a semiclassical description of the fluctuation properties based on the Ornstein-Uhlenbeck stochastic process. As an illustration, we analyze the phase correlation functions and the full statistical distributions of the interference between two one-dimensional systems, either independent or tunnel-coupled, and compare with the Luttinger-liquid theory.

  2. One-dimensional crystal growth model on a square lattice substrate

    NASA Astrophysics Data System (ADS)

    Cheng, Yi; Lu, Chenxi; Yang, Bo; Tao, Xiangming; Wang, Jianfeng; Ye, Gaoxiang

    2016-08-01

    A one-dimensional crystal growth model along the preferential growth direction is established. The simulation model is performed on a square lattice substrate. First, particles are deposited homogeneously and, as a result, each of the lattice sites is occupied by one particle. In the subsequent stage, N nuclei are selected randomly on the substrate, then the growth process starts by adsorbing the surrounding particles along the preferential growth directions of the crystals. Finally, various one-dimensional crystals with different length and width form. The simulation results are in good agreement with the experimental findings.

  3. Conversion method of powder inelastic scattering data for one-dimensional systems

    SciTech Connect

    Tomiyasu, Dr. Keisuke; Fujita, Prof. Masaki; Kolesnikov, Alexander I; Bewley, Robert I.; Bull, Dr. Martyn J.; Bennington, Dr. Stephen M.

    2009-01-01

    Extracting dispersive magnetic excitations from inelastic neutron scattering data usually requires large single crystals. We present a simple yet powerful method for extracting such information from polycrystalline or powder data for one-dimensional systems. We demonstrate the effectiveness of this data treatment by extracting dispersion curves from powder inelastic neutron scattering data on the one-dimensional spin-half systems: CuGeO3 and Rb2Cu2Mo3O12. For many such materials it is not possible to grow sufficiently large crystals and this method offers a quick and efficient way to study their magnetic excitations.

  4. One-dimensional edge state of Bi thin film grown on Si(111)

    SciTech Connect

    Kawakami, Naoya; Lin, Chun-Liang; Kawai, Maki; Takagi, Noriaki; Arafune, Ryuichi

    2015-07-20

    The geometric and electronic structures of the Bi thin film grown on Si(111) were investigated by using scanning tunneling microscopy and spectroscopy. We have found two types of edges, one of which hosts an electronic state localized one-dimensionally. We also revealed the energy dispersion of the localized edge state from the evolution of quasiparticle interference patterns as a function of energy. These spectroscopic findings well reproduce those acquired for the cleaved surface of the bulk Bi crystal [I. K. Drozdov et al., Nat. Phys. 10, 664 (2014)]. The present results indicate that the deposited Bi film provides a tractable stage for further scrutiny of the one-dimensional edge state.

  5. Initial-boundary value problem for the one dimensional Thirring model

    NASA Astrophysics Data System (ADS)

    Naumkin, I. P.

    2016-10-01

    We consider the inhomogeneous Dirichlet initial-boundary value problem for the one dimensional Thirring model. We prove the local existence of solutions and global existence of small solutions. Moreover, we obtain a sharp estimate in the uniform norm for the global solutions and we prove the existence of a modified low-energy scattering for this model.

  6. Simple Two-Dimensional Corrections for One-Dimensional Pulse Tube Models

    NASA Technical Reports Server (NTRS)

    Lee, J. M.; Kittel, P.; Timmerhaus, K. D.; Radebaugh, R.

    2004-01-01

    One-dimensional oscillating flow models are very useful for designing pulse tubes. They are simple to use, not computationally intensive, and the physical relationship between temperature, pressure and mass flow are easy to understand when used in conjunction with phasor diagrams. They do not possess, however, the ability to directly calculate thermal and momentum diffusion in the direction transverse to the oscillating flow. To account for transverse effects, lumped parameter corrections, which are obtained though experiment, must be used. Or two-dimensional solutions of the differential fluid equations must be obtained. A linear two-dimensional solution to the fluid equations has been obtained. The solution provides lumped parameter corrections for one-dimensional models. The model accounts for heat transfer and shear flow between the gas and the tube. The complex Nusselt number and complex shear wall are useful in describing these corrections, with phase relations and amplitudes scaled with the Prandtl and Valensi numbers. The calculated ratio, a, between a two-dimensional solution of the oscillating temperature and velocity and a one-dimensional solution for the same shows a scales linearly with Va for Va less than 30. In this region alpha less than 0.5, that is, the enthalpy flow calculated with a two-dimensional model is 50% of a calculation using a one-dimensional model. For Va greater than 250, alpha = 0.8, showing that diffusion is still important even when it is confined to a thing layer near the tube wall.

  7. One-dimensional random field Ising model and discrete stochastic mappings

    SciTech Connect

    Behn, U.; Zagrebnov, V.A.

    1987-06-01

    Previous results relating the one-dimensional random field Ising model to a discrete stochastic mapping are generalized to a two-valued correlated random (Markovian) field and to the case of zero temperature. The fractal dimension of the support of the invariant measure is calculated in a simple approximation and its dependence on the physical parameters is discussed.

  8. Simple One-Dimensional Quantum-Mechanical Model for a Particle Attached to a Surface

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2010-01-01

    We present a simple one-dimensional quantum-mechanical model for a particle attached to a surface. It leads to the Schrodinger equation for a harmonic oscillator bounded on one side that we solve in terms of Weber functions and discuss the behaviour of the eigenvalues and eigenfunctions. We derive the virial theorem and other exact relationships…

  9. DENSITY-DEPENDENT FLOW IN ONE-DIMENSIONAL VARIABLY-SATURATED MEDIA

    EPA Science Inventory

    A one-dimensional finite element is developed to simulate density-dependent flow of saltwater in variably saturated media. The flow and solute equations were solved in a coupled mode (iterative), in a partially coupled mode (non-iterative), and in a completely decoupled mode. P...

  10. One-Dimensional Collision Carts Computer Model and Its Design Ideas for Productive Experiential Learning

    ERIC Educational Resources Information Center

    Wee, Loo Kang

    2012-01-01

    We develop an Easy Java Simulation (EJS) model for students to experience the physics of idealized one-dimensional collision carts. The physics model is described and simulated by both continuous dynamics and discrete transition during collision. In designing the simulations, we discuss briefly three pedagogical considerations namely (1) a…

  11. Improved implementation of the HLL approximate Riemann solver for one-dimensional open channel flows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several new techniques are proposed to overcome the deficiencies in the conventional formulation of the approximate Riemann solvers for one-dimensional open channel flows, which include numerical imbalance and inaccuracy in the solution of discharge. The former arises in the case of irregular geomet...

  12. Cooperative jump motions of jammed particles in a one-dimensional periodic potential.

    PubMed

    Sakaguchi, Hidetsugu

    2009-12-01

    Cooperative jump motions are studied for mutually interacting particles in a one-dimensional periodic potential. The diffusion constant for the cooperative motion in systems including a small number of particles is numerically calculated and it is compared with theoretical estimates. We find that the size distribution of the cooperative jump motions obeys an exponential law in a large system.

  13. Comparing the Impact of Dynamic and Static Media on Students' Learning of One-Dimensional Kinematics

    ERIC Educational Resources Information Center

    Mešic, Vanes; Dervic, Dževdeta; Gazibegovic-Busuladžic, Azra; Salibašic, Džana; Erceg, Nataša

    2015-01-01

    In our study, we aimed to compare the impact of simulations, sequences of printed simulation frames and conventional static diagrams on the understanding of students with regard to the one-dimensional kinematics. Our student sample consisted of three classes of middle years students (N = 63; mostly 15 year-olds). These three classes served as…

  14. Analytical solution for one-dimensional advection-dispersion transport equation with distance-dependent coefficients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mathematical models describing contaminant transport in heterogeneous porous media are often formulated as an advection-dispersion transport equation with distance-dependent transport coefficients. In this work, a general analytical solution is presented for the linear, one-dimensional advection-di...

  15. Results from field tests of the one-dimensional Time-Encoded Imaging System.

    SciTech Connect

    Marleau, Peter; Brennan, James S.; Brubaker, Erik

    2014-09-01

    A series of field experiments were undertaken to evaluate the performance of the one dimensional time encoded imaging system. The significant detection of a Cf252 fission radiation source was demonstrated at a stand-off of 100 meters. Extrapolations to different quantities of plutonium equivalent at different distances are made. Hardware modifications to the system for follow on work are suggested.

  16. Non-one-dimensional self-similar solutions with plane waves in gas dynamics

    NASA Astrophysics Data System (ADS)

    Poslavskii, S. A.; Shikin, I. S.

    1986-02-01

    A set of new exact self-similar solutions describing the non-one-dimensional adiabatic motions of an ideal gas with plane waves is presented. The solutions include homogeneous gas expansion in planes perpendicular to the direction of the principal motion. It is shown that for such solutions, the system of gasdynamic equations is reduced to a system of ordinary differental equations.

  17. Local reduction of certain wave operators to one-dimensional form

    NASA Technical Reports Server (NTRS)

    Roe, Philip

    1994-01-01

    It is noted that certain common linear wave operators have the property that linear variation of the initial data gives rise to one-dimensional evolution in a plane defined by time and some direction in space. The analysis is given For operators arising in acoustics, electromagnetics, elastodynamics, and an abstract system.

  18. ONE-DIMENSIONAL HYDRODYNAMIC/SEDIMENT TRANSPORT MODEL FOR STREAM NETWORKS: TECHNICAL REPORT

    EPA Science Inventory

    This technical report describes a new sediment transport model and the supporting post-processor, and sampling procedures for sediments in streams. Specifically, the following items are described herein:

    EFDC1D - This is a new one-dimensional hydrodynamic and sediment tr...

  19. An Autonomous Star Identification Algorithm Based on One-Dimensional Vector Pattern for Star Sensors.

    PubMed

    Luo, Liyan; Xu, Luping; Zhang, Hua

    2015-07-07

    In order to enhance the robustness and accelerate the recognition speed of star identification, an autonomous star identification algorithm for star sensors is proposed based on the one-dimensional vector pattern (one_DVP). In the proposed algorithm, the space geometry information of the observed stars is used to form the one-dimensional vector pattern of the observed star. The one-dimensional vector pattern of the same observed star remains unchanged when the stellar image rotates, so the problem of star identification is simplified as the comparison of the two feature vectors. The one-dimensional vector pattern is adopted to build the feature vector of the star pattern, which makes it possible to identify the observed stars robustly. The characteristics of the feature vector and the proposed search strategy for the matching pattern make it possible to achieve the recognition result as quickly as possible. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition accuracy and robustness by the proposed algorithm are better than those by the pyramid algorithm, the modified grid algorithm, and the LPT algorithm. The theoretical analysis and experimental results show that the proposed algorithm outperforms the other three star identification algorithms.

  20. Suggested Courseware for the Non-Calculus Physics Student: Measurement, Vectors, and One-Dimensional Motion.

    ERIC Educational Resources Information Center

    Mahoney, Joyce; And Others

    1988-01-01

    Evaluates 16 commercially available courseware packages covering topics for introductory physics. Discusses the price, sub-topics, program type, interaction, time, calculus required, graphics, and comments of each program. Recommends two packages in measurement and vectors, and one-dimensional motion respectively. (YP)

  1. Computer Simulation of a Particle in a One-Dimensional Double or Triple Potential Well.

    ERIC Educational Resources Information Center

    Humberston, J. W.; And Others

    1983-01-01

    A computer program was written for a model system in quantum mechanics (particle in a one-dimensional finite square well potential). Described is a major extension of the single-well program to treat problem of a particle in a double/triple finite square potential well. Technical/educational features of the program are considered. (Author/JN)

  2. Exact trace formulas for a class of one-dimensional ray-splitting systems

    SciTech Connect

    Dabaghian, Y.; Jensen, R. V.; Blumel, R.

    2001-06-01

    Using quantum graph theory we establish that the ray-splitting trace formula proposed by Couchman [Phys. Rev. A >46, 6193 (1992)] is exact for a class of one-dimensional ray-splitting systems. Important applications in combinatorics are suggested.

  3. Analysis of reverse combustion in tar sands: a one-dimensional model

    SciTech Connect

    Amr, A.

    1980-08-01

    This paper describes a one-dimensional numerical model which simulates oil recovery from tar sands by reverse combustion. The method of lines is used to solve the nonlinear differential equations describing the flow. The effects of volumetric air flux on the peak temperature, flame velocity, and oil recovery efficiency are reported. The results are compared to the results of relevant experimental studies.

  4. Quantum bright solitons in a quasi-one-dimensional optical lattice

    NASA Astrophysics Data System (ADS)

    Barbiero, Luca; Salasnich, Luca

    2014-06-01

    We study a quasi-one-dimensional attractive Bose gas confined in an optical lattice with a superimposed harmonic potential by analyzing the one-dimensional Bose-Hubbard Hamiltonian of the system. Starting from the three-dimensional many-body quantum Hamiltonian, we derive strong inequalities involving the transverse degrees of freedom under which the one-dimensional Bose-Hubbard Hamiltonian can be safely used. To have a reliable description of the one-dimensional ground state, which we call a quantum bright soliton, we use the density-matrix-renormalization-group (DMRG) technique. By comparing DMRG results with mean-field (MF) ones, we find that beyond-mean-field effects become relevant by increasing the attraction between bosons or by decreasing the frequency of the harmonic confinement. In particular, we find that, contrary to the MF predictions based on the discrete nonlinear Schrödinger equation, average density profiles of quantum bright solitons are not shape-invariant. We also use the time-evolving-block-decimation method to investigate the dynamical properties of bright solitons when the frequency of the harmonic potential is suddenly increased. This quantum quench induces a breathing mode whose period crucially depends on the final strength of the superimposed harmonic confinement.

  5. An Autonomous Star Identification Algorithm Based on One-Dimensional Vector Pattern for Star Sensors

    PubMed Central

    Luo, Liyan; Xu, Luping; Zhang, Hua

    2015-01-01

    In order to enhance the robustness and accelerate the recognition speed of star identification, an autonomous star identification algorithm for star sensors is proposed based on the one-dimensional vector pattern (one_DVP). In the proposed algorithm, the space geometry information of the observed stars is used to form the one-dimensional vector pattern of the observed star. The one-dimensional vector pattern of the same observed star remains unchanged when the stellar image rotates, so the problem of star identification is simplified as the comparison of the two feature vectors. The one-dimensional vector pattern is adopted to build the feature vector of the star pattern, which makes it possible to identify the observed stars robustly. The characteristics of the feature vector and the proposed search strategy for the matching pattern make it possible to achieve the recognition result as quickly as possible. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition accuracy and robustness by the proposed algorithm are better than those by the pyramid algorithm, the modified grid algorithm, and the LPT algorithm. The theoretical analysis and experimental results show that the proposed algorithm outperforms the other three star identification algorithms. PMID:26198233

  6. Sol-gel fabrication of one-dimensional photonic crystals with predicted transmission spectra

    NASA Astrophysics Data System (ADS)

    Ilinykh, V. A.; Matyushkin, L. B.

    2016-08-01

    One-dimensional multilayer structures of periodically alternating low refractive index (silica) and high refractive index (titania) materials have been deposited by sol-gel spincoating. Experimental spectra of the structures are in agreement with spectra calculated by transfer matrix technique. As an example, theoretical and experimental spectra with a stop band corresponding 600 nm-reflection are shown.

  7. One-dimensional simulation of temperature and moisture in atmospheric and soil boundary layers

    NASA Technical Reports Server (NTRS)

    Bornstein, R. D.; Santhanam, K.

    1981-01-01

    Meteorologists are interested in modeling the vertical flow of heat and moisture through the soil in order to better simulate the vertical and temporal variations of the atmospheric boundary layer. The one dimensional planetary boundary layer model of is modified by the addition of transport equations to be solved by a finite difference technique to predict soil moisture.

  8. One-dimensional lipid bilayers on carbon nanotubes: Structure and properties

    NASA Astrophysics Data System (ADS)

    Artyukhin, Alexander Borisovich

    In this work we report design, assembly, and properties of one-dimensional lipid bilayers wrapped around polymer-coated carbon nanotubes. We propose to use this platform as a tool for interfacing nanomaterials with biological systems. We start by presenting a new general procedure for noncovalent modification of carbon nanotubes based on polyelectrolyte layer-by-layer assembly. We confirm formation of multilayer polymer structures around individual carbon nanotubes by transmission electron microscopy and confocal fluorescence microscopy, and demonstrate that sign of the outmost polymer layer controls surface properties of the multilayer assembly. We study how rigidity of a polymer chain influences its ability to adsorb onto high curvature substrates, such as carbon nanotubes. We then build the one-dimensional lipid bilayer structure by spontaneous assembly of lipid molecules in a continuous nanoshell around a template of a carbon nanotube wrapped with hydrophilic polymer cushion layers. We demonstrate that such one-dimensional lipid membranes are fluid and can heal defects, even over repeated damage-recovery cycles. Measured diffusion coefficients of lipid molecules in our polymer-supported bilayers are about 3 orders of magnitude lower than typical values for fluid lipid membranes, which we attribute to strong electrostatic polyelectrolyte-lipid interactions. To explore the potential for device integration of one-dimensional bilayers we investigate effect of polyelectrolyte multilayers on electrical properties of carbon nanotube transistors. We demonstrate that complex interaction of adsorbed species with the device substrate can produce significant and sometimes unexpected side effects on device characteristics. Finally, we fabricate transistors with suspended carbon nanotube channels and devise a method to transfer them in liquid. It allows us to assemble one-dimensional lipid membranes on carbon nanotube devices, characterize their electrical properties, and

  9. Bioinspired One-Dimensional Nano-Wrinkles Guide Liquid Behaviors at the Liquid-Solid Interfaces.

    PubMed

    Li, Jing; Sun, Quanmei; Chen, Long; Feng, Jiantao; Han, Dong

    2016-01-01

    Learning from nature concerning how nanostructured surfaces interact with liquids may provide insight into better understanding of inside living biological interfaces bearing these nanostructures and further development of innovative materials contacting water. Here we investigate the dynamic behaviour of water droplet interacting with one-dimensional nano-wrinkles of different size on polydimethylsiloxane (PDMS) surface. The structure design of the variationally one-dimensional nano-wrinkles is inspired by in vivo responding topographic changes in aortic intima, which was characterized with liquid-phase atomic force microscopy. We show here that increasing the amplitude of the wrinkles promotes the spreading and energy dissipation of liquid droplets on the wrinkled interfaces. This result suggests a possible bio-protection mechanism of blood vessels via its structural changes on the aortic intima against elevated flowing blood, and provides a basis for tuning interfacial nanostructure of optimal durability against wearing by the liquid behaviors. PMID:27398541

  10. Bethe ansatz density-functional theory of ultracold repulsive fermions in one-dimensional optical lattices

    SciTech Connect

    Xianlong, Gao; Polini, Marco; Tosi, M. P.; Campo, Vivaldo L. Jr.; Capelle, Klaus; Rigol, Marcos

    2006-04-15

    We present an extensive numerical study of the ground-state properties of confined repulsively interacting fermions in one-dimensional optical lattices. Detailed predictions for the atom-density profiles are obtained from parallel Kohn-Sham density-functional calculations and quantum Monte Carlo simulations. The density-functional calculations employ a Bethe ansatz based local-density approximation for the correlation energy that accounts for Luttinger-liquid and Mott-insulator physics. Semianalytical and fully numerical formulations of this approximation are compared with each other and with a cruder Thomas-Fermi-type local-density approximation for the total energy. Precise quantum Monte Carlo simulations are used to assess the reliability of the various local-density approximations, and in conjunction with these provide a detailed microscopic picture of the consequences of the interplay between particle-particle interactions and confinement in one-dimensional systems of strongly correlated fermions.

  11. Perpetual motion of a mobile impurity in a one-dimensional quantum gas

    NASA Astrophysics Data System (ADS)

    Lychkovskiy, O.

    2014-03-01

    Consider an impurity particle injected in a degenerate one-dimensional gas of noninteracting fermions (or, equivalently, Tonks-Girardeau bosons) with some initial momentum p0. We examine the infinite-time value of the momentum of the impurity, p∞, as a function of p0. A lower bound on |p∞(p0)| is derived under fairly general conditions. The derivation, based on the existence of the lower edge of the spectrum of the host gas, does not resort to any approximations. The existence of such bound implies the perpetual motion of the impurity in a one-dimensional gas of noninteracting fermions or Tonks-Girardeau bosons at zero temperature. The bound admits an especially simple and useful form when the interaction between the impurity and host particles is everywhere repulsive.

  12. Scattering of two coherent photons inside a one-dimensional coupled-resonator waveguide

    SciTech Connect

    Alexanian, Moorad

    2010-01-15

    We consider the coherent propagation of n photons in a one-dimensional coupled-resonator waveguide for n=2,3,4.... The scattering by a three-level atom, which resides in one of the resonators of the waveguide and gives rise to only two-photon transitions, results in a perfect quantum switch that allows either total reflection or total transmission. This is to be contrasted to the case of a single photon inside a one-dimensional resonant waveguide scattered by a two-level system with single-photon transitions where only total reflection can be accomplished; viz. the system behaves only as a perfect mirror but not as an ideal, transparent medium.

  13. Spin-incoherent one-dimensional spin-1 Bose Luttinger liquid

    NASA Astrophysics Data System (ADS)

    Jen, H. H.; Yip, S.-K.

    2016-09-01

    We investigate spin-incoherent Luttinger liquid of a one-dimensional spin-1 Bose gas in a harmonic trap. In this regime highly degenerate spin configurations emerge since the energy splitting between different spin states is much less than the thermal energy of the system, while the temperature is low enough that the lowest energetic orbitals are occupied. As an example we numerically study the momentum distribution of a one-dimensional spin-1 Bose gas in Tonks-Girardeau gas limit and in the sector of zero magnetization. We find that the momentum distributions broaden as the number of atoms increase due to the averaging of spin function overlaps. Large momentum (p ) asymptotic is analytically derived, showing the universal 1 /p4 dependence. We demonstrate that the spin-incoherent Luttinger liquid has a momentum distribution also distinct from spinless bosons at finite temperature.

  14. ODTLES : a model for 3D turbulent flow based on one-dimensional turbulence modeling concepts.

    SciTech Connect

    McDermott, Randy; Kerstein, Alan R.; Schmidt, Rodney Cannon

    2005-01-01

    This report describes an approach for extending the one-dimensional turbulence (ODT) model of Kerstein [6] to treat turbulent flow in three-dimensional (3D) domains. This model, here called ODTLES, can also be viewed as a new LES model. In ODTLES, 3D aspects of the flow are captured by embedding three, mutually orthogonal, one-dimensional ODT domain arrays within a coarser 3D mesh. The ODTLES model is obtained by developing a consistent approach for dynamically coupling the different ODT line sets to each other and to the large scale processes that are resolved on the 3D mesh. The model is implemented computationally and its performance is tested and evaluated by performing simulations of decaying isotropic turbulence, a standard turbulent flow benchmarking problem.

  15. Theoretical and experimental study of electromagnetic forces induced in one-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Lugo, J. E.; Doti, Rafael; Faubert, Jocelyn; Sanchez, Noemi; Sanchez, Javier; Palomino, Martha A.; de la Mora, M. Beatriz; del Rio, J. Antonio

    2013-10-01

    We studied theoretically and experimentally the induction of electromagnetic forces in one-dimensional photonic crystals with localized defects when light impinges transversally to the defect layer. The theoretical calculations indicate that the electromagnetic forces increases at a certain frequency that coincide with a defect photonic state. The photonic structure consists of a microcavity like structure formed of two one-dimensional photonic crystals made of free-standing porous silicon, separated by variable air gap and the working wavelength is 633 nm. The force generation is made evident by driving a laser light by means of a chopper; the light hits the photonic structure and induces a vibration and the vibration is characterized by using a very sensitive vibrometer.

  16. Sub-Fickean Diffusion in a One-Dimensional Plasma Ring

    NASA Astrophysics Data System (ADS)

    Theisen, W. L.

    2013-12-01

    A one-dimensional dusty plasma ring is formed in a strongly-coupled complex plasma. The dust particles in the ring can be characterized as a one-dimensional system where the particles cannot pass each other. The particles perform random walks due to thermal motions. This single-file self diffusion is characterized by the mean-squared displacement (msd) of the individual particles which increases with time t. Diffusive processes that follow Ficks law predict that the msd increases as t, however, single-file diffusion is sub-Fickean meaning that the msd is predicted to increase as t^(1/2). Particle position data from the dusty plasma ring is analyzed to determine the scaling of the msd with time. Results are compared with predictions of single-file diffusion theory.

  17. A one-dimensional model of solid-earth electrical resistivity beneath Florida

    USGS Publications Warehouse

    Blum, Cletus; Love, Jeffrey J.; Pedrie, Kolby; Bedrosian, Paul A.; Rigler, E. Joshua

    2015-11-19

    An estimated one-dimensional layered model of electrical resistivity beneath Florida was developed from published geological and geophysical information. The resistivity of each layer is represented by plausible upper and lower bounds as well as a geometric mean resistivity. Corresponding impedance transfer functions, Schmucker-Weidelt transfer functions, apparent resistivity, and phase responses are calculated for inducing geomagnetic frequencies ranging from 10−5 to 100 hertz. The resulting one-dimensional model and response functions can be used to make general estimates of time-varying electric fields associated with geomagnetic storms such as might represent induction hazards for electric-power grid operation. The plausible upper- and lower-bound resistivity structures show the uncertainty, giving a wide range of plausible time-varying electric fields.

  18. Fractional quantization of the topological charge pumping in a one-dimensional superlattice

    NASA Astrophysics Data System (ADS)

    Marra, Pasquale; Citro, Roberta; Ortix, Carmine

    2015-03-01

    A one-dimensional quantum charge pump transfers a quantized charge in each pumping cycle. This quantization is topologically robust, being analogous to the quantum Hall effect. The charge transferred in a fraction of the pumping period is instead generally unquantized. We show, however, that with specific symmetries in parameter space the charge transferred at well-defined fractions of the pumping period is quantized as integer fractions of the Chern number. We illustrate this in a one-dimensional Harper-Hofstadter model and show that the fractional quantization of the topological charge pumping is independent of the specific boundary conditions taken into account. We further discuss the relevance of this phenomenon for cold atomic gases in optical superlattices.

  19. Self-organization of cosmic radiation pressure instability. II - One-dimensional simulations

    NASA Technical Reports Server (NTRS)

    Hogan, Craig J.; Woods, Jorden

    1992-01-01

    The clustering of statistically uniform discrete absorbing particles moving solely under the influence of radiation pressure from uniformly distributed emitters is studied in a simple one-dimensional model. Radiation pressure tends to amplify statistical clustering in the absorbers; the absorbing material is swept into empty bubbles, the biggest bubbles grow bigger almost as they would in a uniform medium, and the smaller ones get crushed and disappear. Numerical simulations of a one-dimensional system are used to support the conjecture that the system is self-organizing. Simple statistics indicate that a wide range of initial conditions produce structure approaching the same self-similar statistical distribution, whose scaling properties follow those of the attractor solution for an isolated bubble. The importance of the process for large-scale structuring of the interstellar medium is briefly discussed.

  20. One-dimensional hyperbolic transport: Positivity and admissible boundary conditions derived from the wave formulation

    NASA Astrophysics Data System (ADS)

    Brasiello, Antonio; Crescitelli, Silvestro; Giona, Massimiliano

    2016-05-01

    We consider the one-dimensional Cattaneo equation for transport of scalar fields such as solute concentration and temperature in mass and heat transport problems, respectively. Although the Cattaneo equation admits a stochastic interpretation-at least in the one-dimensional case-negative concentration values can occur in boundary-value problems on a finite interval. This phenomenon stems from the probabilistic nature of this model: the stochastic interpretation provides constraints on the admissible boundary conditions, as can be deduced from the wave formulation here presented. Moreover, as here shown, energetic inequalities and the dissipative nature of the equation provide an alternative way to derive the same constraints on the boundary conditions derived by enforcing positivity. The analysis reported is also extended to transport problems in the presence of a biasing velocity field. Several general conclusions are drawn from this analysis that could be extended to the higher-dimensional case.

  1. Exact canonically conjugate momenta approach to a one-dimensional neutron-proton system, I

    NASA Astrophysics Data System (ADS)

    Nishiyama, Seiya; da Providência, João

    2015-06-01

    Introducing collective variables, a collective description of nuclear surface oscillations has been developed with the first-quantized language, contrary to the second-quantized one in Sunakawa's approach for a Bose system. It overcomes difficulties remaining in the traditional theories of nuclear collective motions: Collective momenta are not exact canonically conjugate to collective coordinates and are not independent. On the contrary to such a description, Tomonaga first gave the basic idea to approach elementary excitations in a one-dimensional Fermi system. The Sunakawa's approach for a Fermi system is also expected to work well for such a problem. In this paper, on the isospin space, we define a density operator and further following Tomonaga, introduce a collective momentum. We propose an exact canonically momenta approach to a one-dimensional neutron-proton (N-P) system under the use of the Grassmann variables.

  2. On one-dimensional stretching functions for finite-difference calculations. [computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Vinokur, M.

    1983-01-01

    The class of one-dimensional stretching functions used in finite-difference calculations is studied. For solutions containing a highly localized region of rapid variation, simple criteria for a stretching function are derived using a truncation error analysis. These criteria are used to investigate two types of stretching functions. One an interior stretching function, for which the location and slope of an interior clustering region are specified. The simplest such function satisfying the criteria is found to be one based on the inverse hyperbolic sine. The other type of function is a two-sided stretching function, for which the arbitrary slopes at the two ends of the one-dimensional interval are specified. The simplest such general function is found to be one based on the inverse tangent. Previously announced in STAR as N80-25055

  3. On one-dimensional stretching functions for finite-difference calculations. [computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Vinokur, M.

    1979-01-01

    The class of one-dimensional stretching functions used in finite-difference calculations is studied. For solutions containing a highly localized region of rapid variation, simple criteria for a stretching function are derived using a truncation error analysis. These criteria are used to investigate two types of stretching functions. One is an interior stretching function, for which the location and slope of an interior clustering region are specified. The simplest such function satisfying the criteria is found to be one based on the inverse hyperbolic sine. The other type of function is a two-sided stretching function, for which the arbitrary slopes at the two ends of the one-dimensional interval are specified. The simplest such general function is found to be one based on the inverse tangent.

  4. Apparent Power-Law Behavior of Conductance in Disordered Quasi-One-Dimensional Systems

    NASA Astrophysics Data System (ADS)

    Rodin, Aleksandr; Fogler, Michael

    2011-03-01

    Observation of power-law dependence of conductance on temperature and voltage has been reported for a wide variety of low-dimensional systems(nano-wires, nano-tubes, and conducting polymers). This behavior has been attributed to the Luttinger liquid effects expected in a pure one-dimensional wire. However, the systems studied were neither one-dimensional nor defect-free. Using numerical simulations we show that the power-law behavior can arise from variable-range hopping in an ensemble of non-interacting disordered wires connected in parallel. This power-law behavior holds in restricted ranges of voltage and temperature, typical of experimental situations. Physically, it comes from rare, but highly conducting hopping paths that appear by chance in some members of the ensemble. The power-law exponents and their dependence on system parameters are consistent with the great majority of available empirical data. Supported by Grant NSF DMR-0706654.

  5. Wurtzite GaAs Quantum Wires: One-Dimensional Subband Formation.

    PubMed

    Vainorius, Neimantas; Lehmann, Sebastian; Gustafsson, Anders; Samuelson, Lars; Dick, Kimberly A; Pistol, Mats-Erik

    2016-04-13

    It is of contemporary interest to fabricate nanowires having quantum confinement and one-dimensional subband formation. This is due to a host of applications, for example, in optical devices, and in quantum optics. We have here fabricated and optically investigated narrow, down to 10 nm diameter, wurtzite GaAs nanowires which show strong quantum confinement and the formation of one-dimensional subbands. The fabrication was bottom up and in one step using the vapor-liquid-solid growth mechanism. Combining photoluminescence excitation spectroscopy with transmission electron microscopy on the same individual nanowires, we were able to extract the effective masses of the electrons in the two lowest conduction bands as well as the effective masses of the holes in the two highest valence bands. Our results, combined with earlier demonstrations of thin crystal phase nanodots in GaAs, set the stage for the fabrication of crystal phase quantum dots having full three-dimensional confinement. PMID:27004550

  6. One-dimensional behavior and high thermoelectric power factor in thin indium arsenide nanowires

    SciTech Connect

    Mensch, P.; Karg, S. Schmidt, V.; Gotsmann, B.; Schmid, H.; Riel, H.

    2015-03-02

    Electrical conductivity and Seebeck coefficient of quasi-one-dimensional indium arsenide (InAs) nanowires with 20 nm diameter are investigated. The carrier concentration of the passivated nanowires was modulated by a gate electrode. A thermoelectric power factor of 1.7 × 10{sup −3} W/m K{sup 2} was measured at room temperature. This value is at least as high as in bulk-InAs and exceeds by far typical values of thicker InAs nanowires with three-dimensional properties. The interpretation of the experimental results in terms of power-factor enhancement by one-dimensionality is supported by model calculations using the Boltzmann transport formalism.

  7. Tunable terahertz multichannel filter based on one-dimensional superconductor-dielectric photonic crystals

    SciTech Connect

    Liu, Yang; Yi, Lin

    2014-12-14

    By means of the transfer matrix method, the transmission properties of one-dimensional photonic crystals (PCs) consisting of superconductor and dielectric have been systematically investigated within the terahertz frequency range (0.1–10 THz). It is shown that comb-like resonant peaks in transmission band can be formed without adding any defect layer in superconductor-dielectric PCs, which means that such a one-dimensional periodic structure can serve as a tunable terahertz multichannel filter by using the PCs passband. Furthermore, the influences coming from the period of the structure, the thickness of the components, the permittivity of the dielectric layers, temperature, and the normal conducting electrons on the filtering properties are also numerically investigated.

  8. Properties of one-dimensional molybdenum nanowires in a confined environment

    SciTech Connect

    Sumpter, Bobby G; Meunier, Vincent; Muramatsu, H; Hayashi, T; Kim, Y A; Shimamoto, Daisuke; Terrones Maldonado, Humberto; Dresselhaus, M; Terrones Maldonado, Mauricio; Endo, M

    2009-01-01

    The atomistic mechanism for the self-assembly of molybdenum into one-dimensional metallic nanowires in a confined environment such as a carbon nanotube is investigated using quantum mechanical calculations. We find that Mo does not organize into linear chains but rather prefers to form four atom per unit-cell nanowires that consist of a subunit of a Mo-BCC crystal. Our model explains the 0.3 nm separation between features measured by high-resolution transmission electron microscopy and why the nanotube diameter must be in the 0.70 - 1.0 nm range to accommodate the smallest stable one-dimensional wire. We also computed the electronic band-structure of the Mo wires inside a nanotube and found significant hybridization with the nanotube states, thereby explaining the experimentally observed quenching of fluorescence and the damping of the radial breathing modes as well as an increased resistance to oxidation.

  9. Suppressing Klein tunneling in graphene using a one-dimensional array of localized scatterers.

    PubMed

    Walls, Jamie D; Hadad, Daniel

    2015-01-01

    Graphene's unique physical and chemical properties make it an attractive platform for use in micro- and nanoelectronic devices. However, electrostatically controlling the flow of electrons in graphene can be challenging as a result of Klein tunneling, where electrons normally incident to a one-dimensional potential barrier of height V are perfectly transmitted even as V → ∞. In this study, theoretical and numerical calculations predict that the transmission probability for an electron wave normally incident to a one-dimensional array of localized scatterers can be significantly less than unity when the electron wavelength is smaller than the spacing between scatterers. In effect, placing periodic openings throughout a potential barrier can, somewhat counterintuitively, decrease transmission in graphene. Our results suggest that electrostatic potentials with spatial variations on the order of the electron wavelength can suppress Klein tunneling and could find applications in developing graphene electronic devices. PMID:25678400

  10. On One-Dimensional Stretching Functions for Finite-Difference Calculations

    NASA Technical Reports Server (NTRS)

    Vinokur, M.

    1980-01-01

    The class of one dimensional stretching function used in finite difference calculations is studied. For solutions containing a highly localized region of rapid variation, simple criteria for a stretching function are derived using a truncation error analysis. These criteria are used to investigate two types of stretching functions. One is an interior stretching function, for which the location and slope of an interior clustering region are specified. The simplest such function satisfying the criteria is found to be one based on the inverse hyperbolic sine. The other type of function is a two sided stretching function, for which the arbitrary slopes at the two ends of the one dimensional interval are specified. The simplest such general function is found to be one based on the inverse tangent. The general two sided function has many applications in the construction of finite difference grids.

  11. Single-file water as a one-dimensional Ising model.

    PubMed

    Köfinger, Jürgen; Dellago, Christoph

    2010-09-27

    We show that single-file water in nanopores can be viewed as a one-dimensional Ising model and investigate, on this basis, the static dielectric response of a chain of hydrogen-bonded water molecules to an external field. To this end, we use a recently developed dipole lattice model which accurately captures the free energetics of nanopore water. In this model, the total energy of the system can be expressed as a sum of effective interactions of chain ends and orientational defects. Neglecting these interactions, we essentially obtain the one-dimensional Ising model which allows us to derive analytical expressions for the free energy as a function of the total dipole moment and for the dielectric susceptibility. Our expressions, which agree very well with simulation results, provide the basis for the interpretation of future dielectric spectroscopy experiments on water-filled nanopore membranes.

  12. Mobility and asymmetry effects in one-dimensional rock-paper-scissors games.

    PubMed

    Venkat, Siddharth; Pleimling, Michel

    2010-02-01

    As the behavior of a system composed of cyclically competing species is strongly influenced by the presence of fluctuations, it is of interest to study cyclic dominance in low dimensions where these effects are the most prominent. We here discuss rock-paper-scissors games on a one-dimensional lattice where the interaction rates and the mobility can be species dependent. Allowing only single site occupation, we realize mobility by exchanging individuals of different species. When the interaction and swapping rates are symmetric, a strongly enhanced swapping rate yields an increased mixing of the species, leading to a mean-field-like coexistence even in one-dimensional systems. This coexistence is transient when the rates are asymmetric, and eventually only one species will survive. Interestingly, in our spatial games the dominating species can differ from the species that would dominate in the corresponding nonspatial model. We identify different regimes in the parameter space and construct the corresponding dynamical phase diagram.

  13. One-dimensional turbulence modeling of a turbulent counterflow flame with comparison to DNS

    SciTech Connect

    Jozefik, Zoltan; Kerstein, Alan R.; Schmidt, Heiko; Lyra, Sgouria; Kolla, Hemanth; Chen, Jackie H.

    2015-06-01

    The one-dimensional turbulence (ODT) model is applied to a reactant-to-product counterflow configuration and results are compared with DNS data. The model employed herein solves conservation equations for momentum, energy, and species on a one dimensional (1D) domain corresponding to the line spanning the domain between nozzle orifice centers. The effects of turbulent mixing are modeled via a stochastic process, while the Kolmogorov and reactive length and time scales are explicitly resolved and a detailed chemical kinetic mechanism is used. Comparisons between model and DNS results for spatial mean and root-meansquare (RMS) velocity, temperature, and major and minor species profiles are shown. The ODT approach shows qualitatively and quantitatively reasonable agreement with the DNS data. Scatter plots and statistics conditioned on temperature are also compared for heat release rate and all species. ODT is able to capture the range of results depicted by DNS. However, conditional statistics show signs of underignition.

  14. A one-dimensional model of solid-earth electrical resistivity beneath Florida

    USGS Publications Warehouse

    Blum, Cletus; Love, Jeffrey J.; Pedrie, Kolby; Bedrosian, Paul A.; Rigler, E. Joshua

    2015-01-01

    An estimated one-dimensional layered model of electrical resistivity beneath Florida was developed from published geological and geophysical information. The resistivity of each layer is represented by plausible upper and lower bounds as well as a geometric mean resistivity. Corresponding impedance transfer functions, Schmucker-Weidelt transfer functions, apparent resistivity, and phase responses are calculated for inducing geomagnetic frequencies ranging from 10−5 to 100 hertz. The resulting one-dimensional model and response functions can be used to make general estimates of time-varying electric fields associated with geomagnetic storms such as might represent induction hazards for electric-power grid operation. The plausible upper- and lower-bound resistivity structures show the uncertainty, giving a wide range of plausible time-varying electric fields.

  15. Self organized criticality in an one dimensional magnetized grid. Application to GRB X-ray afterglows

    NASA Astrophysics Data System (ADS)

    Harko, Tiberiu; Mocanu, Gabriela; Stroia, Nicoleta

    2015-05-01

    A simplified one dimensional grid is used to model the evolution of magnetized plasma flow. We implement diffusion laws similar to those so-far used to model magnetic reconnection with Cellular Automata. As a novelty, we also explicitly superimpose a background flow. The aim is to numerically investigate the possibility that Self-Organized Criticality appears in a one dimensional magnetized flow. The cellular automaton's cells store information about the parameter relevant to the evolution of the system being modelled. Under the assumption that this parameter stands for the magnetic field, the magnetic energy released by one grid cell during one individual relaxation event is also computed. Our results show that indeed in this system Self-Organized Criticality is established. The possible applications of this model to the study of the X-ray afterglows of GRBs is also briefly considered.

  16. Synthetic magnetic fluxes and topological order in one-dimensional spin systems

    NASA Astrophysics Data System (ADS)

    Graß, Tobias; Muschik, Christine; Celi, Alessio; Chhajlany, Ravindra W.; Lewenstein, Maciej

    2015-06-01

    Engineering topological quantum order has become a major field of physics. Many advances have been made by synthesizing gauge fields in cold atomic systems. Here we carry over these developments to other platforms which are extremely well suited for quantum engineering, namely, trapped ions and nano-trapped atoms. Since these systems are typically one-dimensional, the action of artificial magnetic fields has so far received little attention. However, exploiting the long-range nature of interactions, loops with nonvanishing magnetic fluxes become possible even in one-dimensional settings. This gives rise to intriguing phenomena, such as fractal energy spectra, flat bands with localized edge states, and topological many-body states. We elaborate on a simple scheme for generating the required artificial fluxes by periodically driving an XY spin chain. Concrete estimates demonstrating the experimental feasibility for trapped ions and atoms in wave guides are given.

  17. Thermal Conductivity of the One-Dimensional Fermi-Hubbard Model.

    PubMed

    Karrasch, C; Kennes, D M; Heidrich-Meisner, F

    2016-09-01

    We study the thermal conductivity of the one-dimensional Fermi-Hubbard model at a finite temperature using a density matrix renormalization group approach. The integrability of this model gives rise to ballistic thermal transport. We calculate the temperature dependence of the thermal Drude weight at half filling for various interaction strengths. The finite-frequency contributions originating from the fact that the energy current is not a conserved quantity are investigated as well. We report evidence that breaking the integrability through a nearest-neighbor interaction leads to vanishing Drude weights and diffusive energy transport. Moreover, we demonstrate that energy spreads ballistically in local quenches with initially inhomogeneous energy density profiles in the integrable case. We discuss the relevance of our results for thermalization in ultracold quantum-gas experiments and for transport measurements with quasi-one-dimensional materials. PMID:27661705

  18. Thermal conductivities of one-dimensional anharmonic/nonlinear lattices: renormalized phonons and effective phonon theory

    NASA Astrophysics Data System (ADS)

    Li, Nianbei; Li, Baowen

    2012-12-01

    Heat transport in low-dimensional systems has attracted enormous attention from both theoretical and experimental aspects due to its significance to the perception of fundamental energy transport theory and its potential applications in the emerging field of phononics: manipulating heat flow with electronic anologs. We consider the heat conduction of one-dimensional nonlinear lattice models. The energy carriers responsible for the heat transport have been identified as the renormalized phonons. Within the framework of renormalized phonons, a phenomenological theory, effective phonon theory, has been developed to explain the heat transport in general one-dimensional nonlinear lattices. With the help of numerical simulations, it has been verified that this effective phonon theory is able to predict the scaling exponents of temperature-dependent thermal conductivities quantitatively and consistently.

  19. Ordering of colloids with competing interactions on quasi-one-dimensional periodic substrates

    NASA Astrophysics Data System (ADS)

    Reichhardt, C.; McDermott, D.; Olson Reichhardt, C. J.

    2014-09-01

    There are many examples of interacting particles that have both repulsive and attractive interaction terms. Assemblies of such particles can form clumps, gel type states, labyrinths and other patterns, while two-dimensional systems with purely repulsive interactions typically form hexagonal crystals. Here we examine the two-dimensional pattern formation of colloids with competing interactions in the presence of a quasi-one dimensional periodic substrate. For soft matter systems, such substrates can be created by various optical means. We show that the substrate can induce various patterns including commensurate bubble phases as well as modulated stripes aligned with the substrate. Beyond colloids, these results should also be general to other systems that can be modeled as particles with competing interactions moving over a surface with a quasi-one dimensional periodic substrate or modulation.

  20. Macrostates Thermodynamics and Its Stable Classical Limit in Global One-Dimensional Quantum General Relativity

    NASA Astrophysics Data System (ADS)

    Glinka, L. A.

    2009-01-01

    Global One-Dimensional Quantum General Relativity is the toy model with nontrivial field theoretical content, describing classical one-dimensional massive bosonic fields related to any 3 + 1 metric, where the dimension is a volume of threedimensional embedding. In fact it constitutes the midisuperspatial Quantum Gravity model. We use one-particle density operator method in order to building macrostates thermodynamics related with any 3 + 1 metric. Taking the Boltzmann gas limit, which is given by the energy equipartition law for the Bose-Einstein gas of space quantum states generated from the Bogoliubov vacuum, we receive consistent with General Relativity thermodynamical degrees of freedom number. It confirm that the proposed Quantum Gravity toy model has well-defined classical limit in accordance with classical gravity theory.

  1. Consistent treatment of viscoelastic effects at junctions in one-dimensional blood flow models

    NASA Astrophysics Data System (ADS)

    Müller, Lucas O.; Leugering, Günter; Blanco, Pablo J.

    2016-06-01

    While the numerical discretization of one-dimensional blood flow models for vessels with viscoelastic wall properties is widely established, there is still no clear approach on how to couple one-dimensional segments that compose a network of viscoelastic vessels. In particular for Voigt-type viscoelastic models, assumptions with regard to boundary conditions have to be made, which normally result in neglecting the viscoelastic effect at the edge of vessels. Here we propose a coupling strategy that takes advantage of a hyperbolic reformulation of the original model and the inherent information of the resulting system. We show that applying proper coupling conditions is fundamental for preserving the physical coherence and numerical accuracy of the solution in both academic and physiologically relevant cases.

  2. Toward modeling of supercritical CO2 flow using the one-dimensional turbulence model

    NASA Astrophysics Data System (ADS)

    Schulz, F. T.; Glawe, C.; Schmidt, H.; Kerstein, A. R.

    2012-04-01

    Within the CCS (Carbon Capture and Storage) technology the transport of captured CO2 is increasingly regarded as the missing link in research. For industrial applications it is essential to transport CO2 from power plants to geological sites through pipelines and well bores. The effectiveness of such a transport could be increased by keeping CO2 in a supercritical state. This however requires a temperature of at least 31Celsius and a pressure above 73.8 bar. If these conditions are not maintained throughout the whole pipeline, which is challenging and expensive under non-laboratory conditions, density and phase changes and pressure fluctuations may result in harmful vibrations of the pipelines. Typically, simulations of pipeline flow are based on large-eddy simulations (LES) or the Reynolds averaged Navier-Stokes (RANS) equations which both do not resolve the smallest turbulent scales or even phase boundaries. Due to the effect that on pipe diameter scales the flow statistically changes predominantly in the wall normal direction one might consider 1D modeling approaches. The work presented here is part of the GeoEn II activities funded by the Federal Ministry of Education and Research (BMBF) to better understand risks and benefits of CCS technology. Our project goal is to better understand the small scale physics in turbulent CO2 flows and to improve subgrid-scale models used in LES codes. To achieve this we use ODT (One-Dimensional Turbulence), a statistical turbulence modeling strategy, where turbulent flow evolution along a notional 1D line of sight is emulated by applying instantaneous maps to represent the effect of individual turbulent eddies on property profiles along the line. The occurrence of an eddy itself is affected by the property profiles, resulting in a self-contained flow evolution that obeys the applicable conservation laws. Using a 1D ansatz permits a higher resolution of boundary and single phase density gradients which is key to understand the

  3. One-dimensional model of interacting-step fluctuations on vicinal surfaces: Analytical formulas and kinetic Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Patrone, Paul N.; Einstein, T. L.; Margetis, Dionisios

    2010-12-01

    We study analytically and numerically a one-dimensional model of interacting line defects (steps) fluctuating on a vicinal crystal. Our goal is to formulate and validate analytical techniques for approximately solving systems of coupled nonlinear stochastic differential equations (SDEs) governing fluctuations in surface motion. In our analytical approach, the starting point is the Burton-Cabrera-Frank (BCF) model by which step motion is driven by diffusion of adsorbed atoms on terraces and atom attachment-detachment at steps. The step energy accounts for entropic and nearest-neighbor elastic-dipole interactions. By including Gaussian white noise to the equations of motion for terrace widths, we formulate large systems of SDEs under different choices of diffusion coefficients for the noise. We simplify this description via (i) perturbation theory and linearization of the step interactions and, alternatively, (ii) a mean-field (MF) approximation whereby widths of adjacent terraces are replaced by a self-consistent field but nonlinearities in step interactions are retained. We derive simplified formulas for the time-dependent terrace-width distribution (TWD) and its steady-state limit. Our MF analytical predictions for the TWD compare favorably with kinetic Monte Carlo simulations under the addition of a suitably conservative white noise in the BCF equations.

  4. The interaction of a Prandtl-Meyer wave and a quasi-one-dimensional flow region

    NASA Astrophysics Data System (ADS)

    Silnikov, M. V.; Chernyshov, M. V.

    2015-04-01

    A mathematical model for the interaction between a Prandtl-Meyer flow and a quasi-one-dimensional subsonic or supersonic stream is developed. The analytical description of the shape of the slipstream dividing two interacting streams is achieved, and its parametrical analysis is performed. The results of the study may be of practical use in supersonic jet flow-obstacle interaction analysis, which is important for the safety of space vehicle launches.

  5. Study of thermal throat of RBCC combustor based on one-dimensional analysis

    NASA Astrophysics Data System (ADS)

    Wang, Ya-jun; Li, Jiang; Qin, Fei; He, Guo-qiang; Shi, Lei

    2015-12-01

    An analysis model was developed to better understand the formation mechanism and variation law of the thermal throat in a rocket-based combined-cycle (RBCC) combustor. This analysis model is based on one-dimensional flow equations and consideration of the variation in factors such as the area, exothermic distribution, and the fuel-rich jet of the rocket. The influence law for the thermal throat under the interaction of the exothermic distribution and the variation of the area is consistent with the heat release models for a gaseous jet and liquid kerosene. The effective cross-sectional area of the jet was calculated and incorporated into the model. The results calculated using the one-dimensional model were found to be consistent with those obtained from a three-dimensional numerical simulation. The position of the thermal throat was predicted with an error of 0.36%. The maximum relative errors of the static pressure among the corresponding points were 7.4% and 9.3% for the static temperature and total pressure, respectively. The one-dimensional model and three-dimensional numerical simulation were validated using experimental data obtained in direct-connect testing. Except for the cavity region, the maximum relative error of the corresponding points between the simulation results and test results was less than 8.9%, and that between the model results and test results was 10.4%. Compared to the fuel equivalence ratio, the expansion ratio, injection location, and exothermic rate have a significant impact on the position of the thermal throat. An optimization study of the RBCC combustor for the ramjet mode was conducted by adjusting the thermal throat. The thrust performance improved by 31.6% at Ma3 after optimization. These results indicate the important role that the one-dimensional model can play in analyzing the thermal throat and guiding the preliminary design of an RBCC combustor.

  6. Motion of Cesium Atoms in the One-Dimensional Magneto-Optical Trap

    NASA Technical Reports Server (NTRS)

    Li, Yimin; Chen, Xuzong; Wang, Qingji; Wang, Yiqiu

    1996-01-01

    The force to which Cs atoms are subjected in the one-dimensional magneto-optical trap (lD-MOT) is calculated, and properties of this force are discussed. Several methods to increase the number of Cs atoms in the lD-MOT are presented on the basis of the analysis of the capture and escape of Cs atoms in the ID-MOT.

  7. Spin wave localization in one-dimensional magnonic microcavity comprising yttrium iron garnet

    SciTech Connect

    Kanazawa, Naoki; Goto, Taichi Inoue, Mitsuteru

    2014-08-28

    We demonstrate the localization of magnetostatic surface waves, i.e., spin waves, in a one-dimensional magnonic microcavity substantialized with periodical conductivity modulation. The narrow localized state is observed inside band gaps and is responsible for a sharp transmission peak. The experimental results strongly agree with the theoretical prediction made with the shape magnetic anisotropy of the propagating medium composed of yttrium iron garnet taken into account.

  8. The one-dimensional Coulomb potential as a generalized function and the hidden O (2) symmetry

    SciTech Connect

    Weber, T.A.; Hammer, C.L. )

    1990-06-01

    The one-dimensional hydrogen atom treating the potential, --{lambda} /{vert bar}{ital x}{vert bar}, is solved as a generalized function. The solutions (although nondegenerate) are nonunique unless fixed by some physical constraint. It is also shown that the hidden {ital O}(2) symmetry is a consequence of using solutions that are eigenfunctions of the operator sgn {ital x}{equivalent to}{ital x}/{vert bar}{ital x}{vert bar}.

  9. Pressure-induced recovery of Fourier's law in one-dimensional momentum-conserving systems.

    PubMed

    Sato, Dye Sk

    2016-07-01

    We report the two typical models of normal heat conduction in one-dimensional momentum-conserving systems. They show the Arrhenius and the non-Arrhenius temperature dependence. We construct the two corresponding phenomenologies, transition-state theory of thermally activated dissociation and the pressure-induced crossover between two fixed points in fluctuating hydrodynamics. Compressibility yields the ballistic fixed point, whose scaling is observed in Fermi-Pasta-Ulam (FPU) β lattices. PMID:27575085

  10. Transition from a Two-Dimensional Superfluid to a One-Dimensional Mott Insulator

    SciTech Connect

    Bergkvist, Sara; Rosengren, Anders; Saers, Robert; Lundh, Emil; Rehn, Magnus; Kastberg, Anders

    2007-09-14

    A two-dimensional system of atoms in an anisotropic optical lattice is studied theoretically. If the system is finite in one direction, it is shown to exhibit a transition between a two-dimensional superfluid and a one-dimensional Mott insulating chain of superfluid tubes. Monte Carlo simulations are consistent with the expectation that the phase transition is of Kosterlitz-Thouless type. The effect of the transition on experimental time-of-flight images is discussed.

  11. Superfluid-insulator transition in strongly disordered one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Yao, Zhiyuan; Pollet, Lode; Prokof'ev, N.; Svistunov, B.

    2016-04-01

    We present an asymptotically exact renormalization-group theory of the superfluid-insulator transition in one-dimensional (1D) disordered systems, with emphasis on an accurate description of the interplay between the Giamarchi-Schulz (instanton-anti-instanton) and weak-link (scratched-XY) criticalities. Combining the theory with extensive quantum Monte Carlo simulations allows us to shed new light on the ground-state phase diagram of the 1D disordered Bose-Hubbard model at unit filling.

  12. Pressure-induced recovery of Fourier's law in one-dimensional momentum-conserving systems

    NASA Astrophysics Data System (ADS)

    Sato, Dye SK

    2016-07-01

    We report the two typical models of normal heat conduction in one-dimensional momentum-conserving systems. They show the Arrhenius and the non-Arrhenius temperature dependence. We construct the two corresponding phenomenologies, transition-state theory of thermally activated dissociation and the pressure-induced crossover between two fixed points in fluctuating hydrodynamics. Compressibility yields the ballistic fixed point, whose scaling is observed in Fermi-Pasta-Ulam (FPU) β lattices.

  13. Residual entropy and waterlike anomalies in the repulsive one dimensional lattice gas.

    PubMed

    da Silva, Fernando Barbosa V; Oliveira, Fernando Albuquerque; Barbosa, Marco Aurélio A

    2015-04-14

    The thermodynamics and kinetics of the one dimensional lattice gas with repulsive interaction are investigated using transfer matrix technique and Monte Carlo simulations. This simple model is shown to exhibit waterlike anomalies in density, thermal expansion coefficient, and self-diffusion. An unified description for the thermodynamic anomalies in this model is achieved based on the ground state residual entropy which appears in the model due to mixing entropy in a ground state phase transition.

  14. Conditioned quantum motion of an atom in a continuously monitored one-dimensional lattice

    NASA Astrophysics Data System (ADS)

    Blattmann, Ralf; Mølmer, Klaus

    2016-05-01

    We consider a quantum particle on a one-dimensional lattice subject to weak local measurements and study its stochastic dynamics conditioned on the measurement outcomes. Depending on the measurement strength our analysis of the quantum trajectories reveals dynamical regimes ranging from quasicoherent wave-packet oscillations to a Zeno-type dynamics. We analyze how these dynamical regimes are directly reflected in the spectral properties of the noisy measurement records.

  15. Exact solution of the one-dimensional Hubbard model with arbitrary boundary magnetic fields

    NASA Astrophysics Data System (ADS)

    Li, Yuan-Yuan; Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

    2014-02-01

    The one-dimensional Hubbard model with arbitrary boundary magnetic fields is solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz in the charge sector, the second eigenvalue problem associated with the spin sector is constructed. It is shown that the second eigenvalue problem can be transformed into that of the inhomogeneous XXX spin chain with arbitrary boundary fields which can be solved via the off-diagonal Bethe ansatz method.

  16. One-dimensional Vlasov simulation of parallel electric fields in two-electron population plasma

    SciTech Connect

    Saharia, K.; Goswami, K. S.

    2007-09-15

    One-dimensional Vlasov simulation in electron current carrying multicomponent plasma seeded with a density depression is presented. Considering two electron populations [one is sufficiently hot ({approx}keV) and the other is cold along with cold background ions], the formation of weak double layers is investigated. Simulation results show that in this numerical setting, formation of such double layers needs the majority of the hot electrons.

  17. Converting Ag nanowire into one-dimensional silver niobate and their enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Lu, Yang; Yu, Qiaonan; Zhang, Feng; Li, Guoqiang; Zhang, Weifeng

    2016-09-01

    We synthesized one-dimensional silver niobate using Ag nanowires as the raw material and template. The final sample is the Ag2Nb4O11/AgNbO3 composite with a uniform distribution of elements, judging from the element analysis. In comparison with the pristine AgNbO3, the composite sample exhibits the enhanced photocatalytic activity for rhodamine B and 2,4-dichlorophene degradation under visible-light irradiation.

  18. Extended supersymmetry and hidden symmetries in one-dimensional matrix quantum mechanics

    NASA Astrophysics Data System (ADS)

    Andrianov, A. A.; Sokolov, A. V.

    2016-01-01

    We study properties of nonlinear supersymmetry algebras realized in the one-dimensional quantum mechanics of matrix systems. Supercharges of these algebras are differential operators of a finite order in derivatives. In special cases, there exist independent supercharges realizing an (extended) supersymmetry of the same super-Hamiltonian. The extended supersymmetry generates hidden symmetries of the super-Hamiltonian. Such symmetries have been found in models with (2×2)-matrix potentials.

  19. Bound state in the continuum in the one-dimensional photonic crystal slab

    NASA Astrophysics Data System (ADS)

    Sadrieva, Z. F.; Bogdanov, A. A.

    2016-08-01

    In this work we developed a design of one-dimensional Si/SiO2 photonic crystal slab supporting so called optical bound states in the continuum - infinitely high-Q optical states with energies lying above the light line of the surrounding space. Such high-Q states are very perspective for many potential applications ranging from on-chip photonics and optical communications to biological sensing and photovoltaics.

  20. Structural features of conducting quasi-one-dimensional organic halides and pseudohalides

    NASA Technical Reports Server (NTRS)

    Williams, R.; Lowe-Ma, C.; Samson, S.

    1982-01-01

    The physical properties of quasi-one-dimensional conductors are profoundly influenced by slight changes in structure. The unusual structural features of this class of materials include only short range order of the anions and structure modulation. The nature of disorder and structure modulation can affect the character of the metal-to-insulator transition at low temperature, and may allow us to make some predictions of low temperature behavior based on room temperature structural properties.

  1. Classical Communication Help and Probabilistic Teleportation with One-Dimensional Non-maximally Entangled Cluster States

    NASA Astrophysics Data System (ADS)

    Xia, Yan; Song, Jie; Song, He-Shan

    2008-06-01

    We present an explicit protocol for probabilistic teleport an arbitrary and unknown two-qubit entangled state via a one-dimensional four-particle non-maximally entangled cluster state. By construction, our four-partite state is not reducible to a pair of Bell states. We show that teleportation can be successfully realized with a certain probability. This protocol indicate that the four-qubit state is a likely candidate for the genuine four-particle analogue to a Bell state.

  2. Strongly confined tunnel-coupled one-dimensional electron systems from an asymmetric double quantum well

    NASA Astrophysics Data System (ADS)

    Buchholz, S. S.; Fischer, S. F.; Kunze, U.; Schuh, D.; Abstreiter, G.

    2008-03-01

    Vertically stacked quantum point contacts (QPCs) are prepared by atomic force microscope (AFM) lithography from an asymmetric GaAs/AlGaAs double quantum well (DQW) heterostructure. Top- and back-gate voltages are used to tune the tunnel-coupled QPCs, and back-gate bias cooling is employed to investigate coupled and decoupled one-dimensional (1D) modes. Parity dependent mode coupling is invoked by the particular asymmetry in the vertical DQW confinement.

  3. One-dimensional Fibonacci grating for far-field super-resolution imaging.

    PubMed

    Wu, Kedi; Wang, Guo Ping

    2013-06-15

    One-dimensional Fibonacci gratings are used to transform evanescent waves into propagating waves for far-field super-resolution imaging. By detecting far-field intensity distributions of light through objects in front of the Fibonacci grating in free space, we can observe the objects with nearly λ/9 spatial resolution. Analytical results are verified by numerical simulations. We also discuss the effect of sampling error on imaging resolution of the system. PMID:23938967

  4. Inverse coefficient problems for one-dimensional heat transfer with a preservation of medium temperature condition

    NASA Astrophysics Data System (ADS)

    Oralsyn, Gulaym

    2016-08-01

    We study an inverse coefficient problem for a model equation for one-dimensional heat transfer with a preservation of medium temperature. It is needed (together with finding its solution) to find time dependent unknown coefficient of the equation. So, for this inverse problem, existence of an unique generalized solution is proved. The main difficulty of the considered problems is that the eigenfunction system of the corresponding boundary value problems does not have the basis property.

  5. Residual entropy and waterlike anomalies in the repulsive one dimensional lattice gas

    SciTech Connect

    Silva, Fernando Barbosa V. da; Oliveira, Fernando Albuquerque; Barbosa, Marco Aurélio A.

    2015-04-14

    The thermodynamics and kinetics of the one dimensional lattice gas with repulsive interaction are investigated using transfer matrix technique and Monte Carlo simulations. This simple model is shown to exhibit waterlike anomalies in density, thermal expansion coefficient, and self-diffusion. An unified description for the thermodynamic anomalies in this model is achieved based on the ground state residual entropy which appears in the model due to mixing entropy in a ground state phase transition.

  6. Emergence of correlated optics in one-dimensional waveguides for classical and quantum atomic gases

    NASA Astrophysics Data System (ADS)

    Ruostekoski, Janne; Javanainen, Juha

    2016-09-01

    We analyze the emergence of correlated optical phenomena in the transmission of light through a waveguide that confines classical or ultracold quantum degenerate atomic ensembles. The conditions of the correlated collective response are identified in terms of atom density, thermal broadening, and photon losses by using stochastic Monte Carlo simulations and transfer matrix methods of transport theory. We also calculate the "cooperative Lamb shift" for the waveguide transmission resonance, and discuss line shifts that are specific to effectively one-dimensional waveguide systems.

  7. Logical Gates Implemented by Solitons at the Junctions Between One-Dimensional Lattices

    NASA Astrophysics Data System (ADS)

    Siccardi, Stefano; Adamatzky, Andrew

    2016-06-01

    We study propagation of solitons on one-dimensional lattices of nodes with Morse interaction between the neighboring nodes. In numerical integration, we demonstrate that solitons colliding at junctions of two lattices can implement AND, OR and NOT Boolean logic gates. The gates are determined by the geometry of the junctions and phase difference of the colliding solitons. We evaluate the feasibility of casing gates in the design of NOR gate.

  8. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems

    NASA Astrophysics Data System (ADS)

    Andersen, M. E. S.; Dehkharghani, A. S.; Volosniev, A. G.; Lindgren, E. J.; Zinner, N. T.

    2016-06-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique.

  9. Spatial mapping and statistical reproducibility of an array of 256 one-dimensional quantum wires

    SciTech Connect

    Al-Taie, H. Kelly, M. J.; Smith, L. W.; Lesage, A. A. J.; Griffiths, J. P.; Beere, H. E.; Jones, G. A. C.; Ritchie, D. A.; Smith, C. G.; See, P.

    2015-08-21

    We utilize a multiplexing architecture to measure the conductance properties of an array of 256 split gates. We investigate the reproducibility of the pinch off and one-dimensional definition voltage as a function of spatial location on two different cooldowns, and after illuminating the device. The reproducibility of both these properties on the two cooldowns is high, the result of the density of the two-dimensional electron gas returning to a similar state after thermal cycling. The spatial variation of the pinch-off voltage reduces after illumination; however, the variation of the one-dimensional definition voltage increases due to an anomalous feature in the center of the array. A technique which quantifies the homogeneity of split-gate properties across the array is developed which captures the experimentally observed trends. In addition, the one-dimensional definition voltage is used to probe the density of the wafer at each split gate in the array on a micron scale using a capacitive model.

  10. Modified Photoluminescence by Silicon-Based One-Dimensional Photonic Crystal Microcavities

    NASA Astrophysics Data System (ADS)

    Chen, San; Qian, Bo; Wei, Jun-Wei; Chen, Kun-Ji; Xu, Jun; Li, Wei; Huang, Xin-Fan

    2005-01-01

    Photoluminescence (PL) from one-dimensional photonic band structures is investigated. The doped photonic crystal with microcavities are fabricated by using alternating hydrogenated amorphous silicon nitride (a-SiNx:H/a-SiNy:H) layers in a plasma enhanced chemical vapour deposition (PECVD) chamber. It is observed that microcavities strongly modify the PL spectra from active hydrogenated amorphous silicon nitride (a-SiNz:H) thin film. By comparison, the wide emission band width 208 nm is strongly narrowed to 11 nm, and the resonant enhancement of the peak PL intensity is about two orders of magnitude with respect to the emission of the λ/2-thick layer of a-SiNz:H. A linewidth of Δλ = 11 nm and a quality factor of Q = 69 are achieved in our one-dimensional a-SiNz photonic crystal microcavities. Measurements of transmittance spectra of the as-grown samples show that the transmittance resonant peak of a cavity mode at 710 nm is introduced into the band gap of one-dimensional photonic crystal distributed Bragg reflector (DBR), which further verifies the microcavity effects.

  11. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems.

    PubMed

    Andersen, M E S; Dehkharghani, A S; Volosniev, A G; Lindgren, E J; Zinner, N T

    2016-01-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique.

  12. Spatial mapping and statistical reproducibility of an array of 256 one-dimensional quantum wires

    NASA Astrophysics Data System (ADS)

    Al-Taie, H.; Smith, L. W.; Lesage, A. A. J.; See, P.; Griffiths, J. P.; Beere, H. E.; Jones, G. A. C.; Ritchie, D. A.; Kelly, M. J.; Smith, C. G.

    2015-08-01

    We utilize a multiplexing architecture to measure the conductance properties of an array of 256 split gates. We investigate the reproducibility of the pinch off and one-dimensional definition voltage as a function of spatial location on two different cooldowns, and after illuminating the device. The reproducibility of both these properties on the two cooldowns is high, the result of the density of the two-dimensional electron gas returning to a similar state after thermal cycling. The spatial variation of the pinch-off voltage reduces after illumination; however, the variation of the one-dimensional definition voltage increases due to an anomalous feature in the center of the array. A technique which quantifies the homogeneity of split-gate properties across the array is developed which captures the experimentally observed trends. In addition, the one-dimensional definition voltage is used to probe the density of the wafer at each split gate in the array on a micron scale using a capacitive model.

  13. Maximizing kinetic energy transfer in one-dimensional many-body collisions

    NASA Astrophysics Data System (ADS)

    Ricardo, Bernard; Lee, Paul

    2015-03-01

    The main problem discussed in this paper involves a simple one-dimensional two-body collision, in which the problem can be extended into a chain of one-dimensional many-body collisions. The result is quite interesting, as it provides us with a thorough mathematical understanding that will help in designing a chain system for maximum energy transfer for a range of collision types. In this paper, we will show that there is a way to improve the kinetic energy transfer between two masses, and the idea can be applied recursively. However, this method only works for a certain range of collision types, which is indicated by a range of coefficients of restitution. Although the concept of momentum, elastic and inelastic collision, as well as Newton’s laws, are taught in junior college physics, especially in Singapore schools, students in this level are not expected to be able to do this problem quantitatively, as it requires rigorous mathematics, including calculus. Nevertheless, this paper provides nice analytical steps that address some common misconceptions in students’ way of thinking about one-dimensional collisions.

  14. The Art of Extracting One-Dimensional Flow Properties from Multi-Dimensional Data Sets

    NASA Technical Reports Server (NTRS)

    Baurle, R. A.; Gaffney, R. L.

    2007-01-01

    The engineering design and analysis of air-breathing propulsion systems relies heavily on zero- or one-dimensional properties (e:g: thrust, total pressure recovery, mixing and combustion efficiency, etc.) for figures of merit. The extraction of these parameters from experimental data sets and/or multi-dimensional computational data sets is therefore an important aspect of the design process. A variety of methods exist for extracting performance measures from multi-dimensional data sets. Some of the information contained in the multi-dimensional flow is inevitably lost when any one-dimensionalization technique is applied. Hence, the unique assumptions associated with a given approach may result in one-dimensional properties that are significantly different than those extracted using alternative approaches. The purpose of this effort is to examine some of the more popular methods used for the extraction of performance measures from multi-dimensional data sets, reveal the strengths and weaknesses of each approach, and highlight various numerical issues that result when mapping data from a multi-dimensional space to a space of one dimension.

  15. Graphics processing unit accelerated one-dimensional blood flow computation in the human arterial tree.

    PubMed

    Itu, Lucian; Sharma, Puneet; Kamen, Ali; Suciu, Constantin; Comaniciu, Dorin

    2013-12-01

    One-dimensional blood flow models have been used extensively for computing pressure and flow waveforms in the human arterial circulation. We propose an improved numerical implementation based on a graphics processing unit (GPU) for the acceleration of the execution time of one-dimensional model. A novel parallel hybrid CPU-GPU algorithm with compact copy operations (PHCGCC) and a parallel GPU only (PGO) algorithm are developed, which are compared against previously introduced PHCG versions, a single-threaded CPU only algorithm and a multi-threaded CPU only algorithm. Different second-order numerical schemes (Lax-Wendroff and Taylor series) are evaluated for the numerical solution of one-dimensional model, and the computational setups include physiologically motivated non-periodic (Windkessel) and periodic boundary conditions (BC) (structured tree) and elastic and viscoelastic wall laws. Both the PHCGCC and the PGO implementations improved the execution time significantly. The speed-up values over the single-threaded CPU only implementation range from 5.26 to 8.10 × , whereas the speed-up values over the multi-threaded CPU only implementation range from 1.84 to 4.02 × . The PHCGCC algorithm performs best for an elastic wall law with non-periodic BC and for viscoelastic wall laws, whereas the PGO algorithm performs best for an elastic wall law with periodic BC.

  16. Strong-coupling ansatz for the one-dimensional Fermi gas in a harmonic potential

    PubMed Central

    Levinsen, Jesper; Massignan, Pietro; Bruun, Georg M.; Parish, Meera M.

    2015-01-01

    A major challenge in modern physics is to accurately describe strongly interacting quantum many-body systems. One-dimensional systems provide fundamental insights because they are often amenable to exact methods. However, no exact solution is known for the experimentally relevant case of external confinement. We propose a powerful ansatz for the one-dimensional Fermi gas in a harmonic potential near the limit of infinite short-range repulsion. For the case of a single impurity in a Fermi sea, we show that our ansatz is indistinguishable from numerically exact results in both the few- and many-body limits. We furthermore derive an effective Heisenberg spin-chain model corresponding to our ansatz, valid for any spin-mixture, within which we obtain the impurity eigenstates analytically. In particular, the classical Pascal’s triangle emerges in the expression for the ground-state wave function. As well as providing an important benchmark for strongly correlated physics, our results are relevant for emerging quantum technologies, where a precise knowledge of one-dimensional quantum states is paramount. PMID:26601220

  17. Plasmonic photocatalytic reactions enhanced by hot electrons in a one-dimensional quantum well

    NASA Astrophysics Data System (ADS)

    Huang, H. J.; Liu, B.-H.; Lin, C.-T.; Su, W. S.

    2015-11-01

    The plasmonic endothermic oxidation of ammonium ions in a spinning disk reactor resulted in light energy transformation through quantum hot charge carriers (QHC), or quantum hot electrons, during a chemical reaction. It is demonstrated with a simple model that light of various intensities enhance the chemical oxidization of ammonium ions in water. It was further observed that light illumination, which induces the formation of plasmons on a platinum (Pt) thin film, provided higher processing efficiency compared with the reaction on a bare glass disk. These induced plasmons generate quantum hot electrons with increasing momentum and energy in the one-dimensional quantum well of a Pt thin film. The energy carried by the quantum hot electrons provided the energy needed to catalyze the chemical reaction. The results indicate that one-dimensional confinement in spherical coordinates (i.e., nanoparticles) is not necessary to provide an extra excited state for QHC generation; an 8 nm Pt thin film for one-dimensional confinement in Cartesian coordinates can also provide the extra excited state for the generation of QHC.

  18. Rational solutions to two- and one-dimensional multicomponent Yajima-Oikawa systems

    NASA Astrophysics Data System (ADS)

    Chen, Junchao; Chen, Yong; Feng, Bao-Feng; Maruno, Ken-ichi

    2015-07-01

    Exact explicit rational solutions of two- and one-dimensional multicomponent Yajima-Oikawa (YO) systems, which contain multi-short-wave components and single long-wave one, are presented by using the bilinear method. For two-dimensional system, the fundamental rational solution first describes the localized lumps, which have three different patterns: bright, intermediate and dark states. Then, rogue waves can be obtained under certain parameter conditions and their behaviors are also classified to above three patterns with different definition. It is shown that the simplest (fundamental) rogue waves are line localized waves which arise from the constant background with a line profile and then disappear into the constant background again. In particular, two-dimensional intermediate and dark counterparts of rogue wave are found with the different parameter requirements. We demonstrate that multirogue waves describe the interaction of several fundamental rogue waves, in which interesting curvy wave patterns appear in the intermediate times. Different curvy wave patterns form in the interaction of different types fundamental rogue waves. Higher-order rogue waves exhibit the dynamic behaviors that the wave structures start from lump and then retreat back to it, and this transient wave possesses the patterns such as parabolas. Furthermore, different states of higher-order rogue wave result in completely distinguishing lumps and parabolas. Moreover, one-dimensional rogue wave solutions with three states are constructed through the further reduction. Specifically, higher-order rogue wave in one-dimensional case is derived under the parameter constraints.

  19. Immobilization and One-Dimensional Arrangement of Virus Capsids with Nanoscale Precision Using DNA Origami

    SciTech Connect

    Stephanopoulos, Nicholas; Liu, Minghui; Tong, Gary J; Li, Zhe; Liu, Yan; Yan, Hao; Francis, Matthew B

    2010-06-24

    DNA origami was used as a scaffold to arrange spherical virus capsids into one-dimensional arrays with precise nanoscale positioning. To do this, we first modified the interior surface of bacteriophage MS2 capsids with fluorescent dyes as a model cargo. An unnatural amino acid on the external surface was then coupled to DNA strands that were complementary to those extending from origami tiles. Two different geometries of DNA tiles (rectangular and triangular) were used. The capsids associated with tiles of both geometries with virtually 100% efficiency under mild annealing conditions, and the location of capsid immobilization on the tile could be controlled by the position of the probe strands. The rectangular tiles and capsids could then be arranged into one-dimensional arrays by adding DNA strands linking the corners of the tiles. The resulting structures consisted of multiple capsids with even spacing (~100 nm). We also used a second set of tiles that had probe strands at both ends, resulting in a one-dimensional array of alternating capsids and tiles. This hierarchical self-assembly allows us to position the virus particles with unprecedented control and allows the future construction of integrated multicomponent systems from biological scaffolds using the power of rationally engineered DNA nanostructures.

  20. An interpolatory ansatz captures the physics of one-dimensional confined Fermi systems

    PubMed Central

    Andersen, M. E. S.; Dehkharghani, A. S.; Volosniev, A. G.; Lindgren, E. J.; Zinner, N. T.

    2016-01-01

    Interacting one-dimensional quantum systems play a pivotal role in physics. Exact solutions can be obtained for the homogeneous case using the Bethe ansatz and bosonisation techniques. However, these approaches are not applicable when external confinement is present. Recent theoretical advances beyond the Bethe ansatz and bosonisation allow us to predict the behaviour of one-dimensional confined systems with strong short-range interactions, and new experiments with cold atomic Fermi gases have already confirmed these theories. Here we demonstrate that a simple linear combination of the strongly interacting solution with the well-known solution in the limit of vanishing interactions provides a simple and accurate description of the system for all values of the interaction strength. This indicates that one can indeed capture the physics of confined one-dimensional systems by knowledge of the limits using wave functions that are much easier to handle than the output of typical numerical approaches. We demonstrate our scheme for experimentally relevant systems with up to six particles. Moreover, we show that our method works also in the case of mixed systems of particles with different masses. This is an important feature because these systems are known to be non-integrable and thus not solvable by the Bethe ansatz technique. PMID:27324113

  1. Plasmonic photocatalytic reactions enhanced by hot electrons in a one-dimensional quantum well

    SciTech Connect

    Huang, H. J. E-mail: hhjhuangkimo@gmail.com; Liu, B. H.; Lin, C. T.; Su, W. S.

    2015-11-15

    The plasmonic endothermic oxidation of ammonium ions in a spinning disk reactor resulted in light energy transformation through quantum hot charge carriers (QHC), or quantum hot electrons, during a chemical reaction. It is demonstrated with a simple model that light of various intensities enhance the chemical oxidization of ammonium ions in water. It was further observed that light illumination, which induces the formation of plasmons on a platinum (Pt) thin film, provided higher processing efficiency compared with the reaction on a bare glass disk. These induced plasmons generate quantum hot electrons with increasing momentum and energy in the one-dimensional quantum well of a Pt thin film. The energy carried by the quantum hot electrons provided the energy needed to catalyze the chemical reaction. The results indicate that one-dimensional confinement in spherical coordinates (i.e., nanoparticles) is not necessary to provide an extra excited state for QHC generation; an 8 nm Pt thin film for one-dimensional confinement in Cartesian coordinates can also provide the extra excited state for the generation of QHC.

  2. A refined one-dimensional rotordynamics model with three-dimensional capabilities

    NASA Astrophysics Data System (ADS)

    Carrera, E.; Filippi, M.

    2016-03-01

    This paper evaluates the vibration characteristics of various rotating structures. The present methodology exploits the one-dimensional Carrera Unified Formulation (1D CUF), which enables one to go beyond the kinematic assumptions of classical beam theories. According to the component-wise (CW) approach, Lagrange-like polynomial expansions (LE) are here adopted to develop the refined displacement theories. The LE elements make it possible to model each structural component of the rotor with an arbitrary degree of accuracy using either different displacement theories or localized mesh refinements. Hamilton's Principle is used to derive the governing equations, which are solved by the Finite Element Method. The CUF one-dimensional theory includes all the effects due to rotation, namely the Coriolis term, spin softening and geometrical stiffening. The numerical simulations have been performed considering a thin ring, discs and bladed-deformable shafts. The effects of the number and the position of the blades on the dynamic stability of the rotor have been evaluated. The results have been compared, when possible, with the 2D and 3D solutions that are available in the literature. CUF models appear very practical to investigate the dynamics of complex rotating structures since they provide 2D and quasi-3D results, while preserving the computational effectiveness of one-dimensional solutions.

  3. Synthesis High Sensivity ZnO Cholesterol Biosensor with One Dimensional Nanostructures

    NASA Astrophysics Data System (ADS)

    Lu, Y. M.; Jhuang, P. G.; Tang, J. F.; Chu, S. Y.; Hsu, CW

    2016-05-01

    Chelosterol ZnO biosensors were synthesized by hydrothermal method with predeposited ALD-ZnO seed layers. The ZnO nanostructures were examined by SEM, XRD, AFM, respectively. The XRD is used to analyze the crystal structures of ZnO seed layers that were grown by ALD process, then using SEM and AFM to analysis the surface morphologies of them. Growing of one dimensional ZnO nanostructures on seed layer of 10nm thickness, reveals high sensitivity of 3.15 uA (mg/dl)-1cm-2(121.96 uAmM-1cm-2) and low Km value of 29mM in 25-100mg/dl cholesterol concentration range. The response time could be as low as 10seconds. In the study, it is found that increasing the aspect ratio of ZnO one dimensional nanostructure also increases the sensitivity and expends the linear measureable range of detecting cholesterol in solution. The thickness of seed layer has a significant influence on sensitivity for one dimensional nano ZnO cholesterol biosensor.

  4. The Extraction of One-Dimensional Flow Properties from Multi-Dimensional Data Sets

    NASA Technical Reports Server (NTRS)

    Baurle, Robert A.; Gaffney, Richard L., Jr.

    2007-01-01

    The engineering design and analysis of air-breathing propulsion systems relies heavily on zero- or one-dimensional properties (e.g. thrust, total pressure recovery, mixing and combustion efficiency, etc.) for figures of merit. The extraction of these parameters from experimental data sets and/or multi-dimensional computational data sets is therefore an important aspect of the design process. A variety of methods exist for extracting performance measures from multi-dimensional data sets. Some of the information contained in the multi-dimensional flow is inevitably lost when any one-dimensionalization technique is applied. Hence, the unique assumptions associated with a given approach may result in one-dimensional properties that are significantly different than those extracted using alternative approaches. The purpose of this effort is to examine some of the more popular methods used for the extraction of performance measures from multi-dimensional data sets, reveal the strengths and weaknesses of each approach, and highlight various numerical issues that result when mapping data from a multi-dimensional space to a space of one dimension.

  5. Application of a One-Dimensional Position Sensitive Chamber on Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Qi, Huirong; Liu, Mei

    2014-02-01

    In the last few years, wire chambers have been frequently used for X-ray detection because of their low cost, large area and reliability. X-ray diffraction is an irreplaceable method for powder crystal lattice measurements. A one-dimensional single-wire chamber has been developed in our lab to provide high position resolution for powder diffraction experiments using synchrotron radiation. There are 200 readout strips of 0.5 mm width with a pitch of 1.0 mm in the X direction, and the working gas is a mixture of Ar and CO2 (90/10). The one-dimensional position of the original ionization point is determined by the adjacent strip's distribution information using the center of gravity method. Recently, a study of the detector's performance and diffraction image was completed at the 1W1B laboratory of the Beijing Synchrotron Radiation Facility (BSRF) using a sample of SiO2. Most of the relative errors between the measured values of diffraction angles and existing data were less than 1%. The best position resolution achieved for the detector in the test was 71 μm (σ value) with a 20 μm slit collimator. Finally, by changing the detector height in incremental distances from the center of the sample, the one-dimensional detector achieved a two-dimensional diffraction imaging function, and the results are in good agreement with standard data.

  6. Graphics processing unit accelerated one-dimensional blood flow computation in the human arterial tree.

    PubMed

    Itu, Lucian; Sharma, Puneet; Kamen, Ali; Suciu, Constantin; Comaniciu, Dorin

    2013-12-01

    One-dimensional blood flow models have been used extensively for computing pressure and flow waveforms in the human arterial circulation. We propose an improved numerical implementation based on a graphics processing unit (GPU) for the acceleration of the execution time of one-dimensional model. A novel parallel hybrid CPU-GPU algorithm with compact copy operations (PHCGCC) and a parallel GPU only (PGO) algorithm are developed, which are compared against previously introduced PHCG versions, a single-threaded CPU only algorithm and a multi-threaded CPU only algorithm. Different second-order numerical schemes (Lax-Wendroff and Taylor series) are evaluated for the numerical solution of one-dimensional model, and the computational setups include physiologically motivated non-periodic (Windkessel) and periodic boundary conditions (BC) (structured tree) and elastic and viscoelastic wall laws. Both the PHCGCC and the PGO implementations improved the execution time significantly. The speed-up values over the single-threaded CPU only implementation range from 5.26 to 8.10 × , whereas the speed-up values over the multi-threaded CPU only implementation range from 1.84 to 4.02 × . The PHCGCC algorithm performs best for an elastic wall law with non-periodic BC and for viscoelastic wall laws, whereas the PGO algorithm performs best for an elastic wall law with periodic BC. PMID:24009129

  7. On the Exit Boundary Condition for One-Dimensional Calculations of Pulsed Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Paxson, Daniel E.

    2002-01-01

    In one-dimensional calculations of pulsed detonation engine (PDE) performance, the exit boundary condition is frequently taken to be a constant static pressure. In reality, for an isolated detonation tube, after the detonation wave arrives at the exit plane, there will be a region of high pressure, which will gradually return to ambient pressure as an almost spherical shock wave expands away from the exit, and weakens. Initially, the flow is supersonic, unaffected by external pressure, but later becomes subsonic. Previous authors have accounted for this situation either by assuming the subsonic pressure decay to be a relaxation phenomenon, or by running a two-dimensional calculation first, including a domain external to the detonation tube, and using the resulting exit pressure temporal distribution as the boundary condition for one-dimensional calculations. These calculations show that the increased pressure does affect the PDE performance. In the present work, a simple model of the exit process is used to estimate the pressure decay time. The planar shock wave emerging from the tube is assumed to transform into a spherical shock wave. The initial strength of the spherical shock wave is determined from comparison with experimental results. Its subsequent propagation, and resulting pressure at the tube exit, is given by a numerical blast wave calculation. The model agrees reasonably well with other, limited, results. Finally, the model was used as the exit boundary condition for a one-dimensional calculation of PDE performance to obtain the thrust wall pressure for a hydrogen-air detonation in tubes of length to diameter ratio (L/D) of 4, and 10, as well as for the original, constant pressure boundary condition. The modified boundary condition had no performance impact for values of L/D > 10, and moderate impact for L/D = 4.

  8. Limitations of one-dimensional mesoscale PBL parameterizations in reproducing mountain-wave flows

    SciTech Connect

    Munoz-Esparza, Domingo; Sauer, Jeremy A.; Linn, Rodman R.; Kosovic, Branko

    2015-12-08

    In this study, mesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, we investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, we use recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill [Sauer et al., J. Atmos. Sci. (2015)], and compare them to four commonly used PBL schemes. We find that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocity and turbulent kinetic energy distribution in the downhill shooting flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift producing errors of ≈ 10 m s–1 at downstream locations due to the presence of a coherent trapped lee wave that does not mix with the atmospheric boundary layer. In contrast, horizontally-integrated momentum flux derived from these PBL schemes displays a realistic pattern. Therefore results from mesoscale models using ensembles of one-dimensional PBL schemes can still potentially be used to parameterize drag effects in general circulation models. Nonetheless, three-dimensional PBL schemes must be developed in order for mesoscale models to accurately represent complex-terrain and other types of flows where one-dimensional PBL assumptions are violated.

  9. Limitations of one-dimensional mesoscale PBL parameterizations in reproducing mountain-wave flows

    DOE PAGESBeta

    Munoz-Esparza, Domingo; Sauer, Jeremy A.; Linn, Rodman R.; Kosovic, Branko

    2015-12-08

    In this study, mesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, we investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, we use recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill [Sauer et al., J. Atmos. Sci. (2015)], and compare them to four commonly used PBL schemes. We find that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocitymore » and turbulent kinetic energy distribution in the downhill shooting flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift producing errors of ≈ 10 m s–1 at downstream locations due to the presence of a coherent trapped lee wave that does not mix with the atmospheric boundary layer. In contrast, horizontally-integrated momentum flux derived from these PBL schemes displays a realistic pattern. Therefore results from mesoscale models using ensembles of one-dimensional PBL schemes can still potentially be used to parameterize drag effects in general circulation models. Nonetheless, three-dimensional PBL schemes must be developed in order for mesoscale models to accurately represent complex-terrain and other types of flows where one-dimensional PBL assumptions are violated.« less

  10. Noise and counting statistics of insulating phases in one-dimensional optical lattices

    SciTech Connect

    Lamacraft, Austen

    2007-07-15

    We discuss the correlation properties of current-carrying states of one-dimensional insulators, which could be realized by applying an impulse to atoms loaded onto an optical lattice. While the equilibrium noise has a gapped spectrum, the quantum uncertainty encoded in the amplitudes for the Zener process gives a zero-frequency contribution out of equilibrium. We derive a general expression for the generating function of the full counting statistics and find that the particle transport obeys binomial statistics with doubled charge, resulting in super-Poissonian noise that originates from the coherent creation of particle-hole pairs.

  11. The controlled synthesis of polyglucose in one-dimensional coordination nanochannels.

    PubMed

    Kobayashi, Yuichiro; Horie, Yuki; Honjo, Kayako; Uemura, Takashi; Kitagawa, Susumu

    2016-04-14

    We demonstrate a feasible method for the preparation of polyglucose (PGlc) with controlled structures, where the polymerization of glucose monomers was performed using one-dimensional nanochannels of [La(1,3,5-benzenetrisbenzoate)(H2O)]n (1). Cationic ring-opening polymerization of 1,6-anhydro-β-D-glucose (levoglucosan) using 1 gave a quasi-linear PGlc, which contrasts highly with the results obtained from conventional polymerizations in bulk and solution. The regulated structure of PGlc prepared using the PCP led to a remarkable improvement in the processability and thermal stability of PGlc, which is useful in applications as a bioplastic.

  12. A One-Dimensional Magnet Based on [Mo(III)(CN)7](4.).

    PubMed

    Wei, Xiao-Qin; Qian, Kun; Wei, Hai-Yan; Wang, Xin-Yi

    2016-06-01

    Self-assembly of the [Mo(III)(CN)7](4-) anion and the Mn(II) unit with a macrocyclic ligand results in the first example of a one-dimensional (1D) chain compound based on the heptacyanomolybdate, [Mn(LN5C10)]2[Mo(CN)7]·2H2O (LN5C10 = 1,4,7,10,13-pentaazacyclopentadecane). Because of the existence of the interchain magnetic coupling, long-rang magnetic ordering was observed in this compound.

  13. Dynamic structure factor of a Bose-Einstein condensate in a one-dimensional optical lattice

    SciTech Connect

    Menotti, C.; Kraemer, M.; Stringari, S.; Pitaevskii, L.

    2003-05-01

    We study the effect of a one-dimensional periodic potential on the dynamic structure factor of an interacting Bose-Einstein condensate at zero temperature. We show that, due to phononic correlations, the excitation strength toward the first band develops a typical oscillating behavior as a function of the momentum transfer, and vanishes at even multiples of the Bragg momentum. The effects of interactions on the static structure factor are found to be significantly amplified by the presence of the optical potential. Our predictions can be tested in stimulated photon scattering experiments.

  14. A one-dimensional quantum walk with multiple-rotation on the coin

    NASA Astrophysics Data System (ADS)

    Xue, Peng; Zhang, Rong; Qin, Hao; Zhan, Xiang; Bian, Zhihao; Li, Jian

    2016-01-01

    We introduce and analyze a one-dimensional quantum walk with two time-independent rotations on the coin. We study the influence on the property of quantum walk due to the second rotation on the coin. Based on the asymptotic solution in the long time limit, a ballistic behaviour of this walk is observed. This quantum walk retains the quadratic growth of the variance if the combined operator of the coin rotations is unitary. That confirms no localization exhibits in this walk. This result can be extended to the walk with multiple time-independent rotations on the coin.

  15. Quantum breathing of an impurity in a one-dimensional bath of interacting bosons.

    PubMed

    Peotta, Sebastiano; Rossini, Davide; Polini, Marco; Minardi, Francesco; Fazio, Rosario

    2013-01-01

    By means of the time-dependent density-matrix renormalization-group (TDMRG) method we are able to follow the real-time dynamics of a single impurity embedded in a one-dimensional bath of interacting bosons. We focus on the impurity breathing mode, which is found to be well described by a single oscillation frequency and a damping rate. If the impurity is very weakly coupled to the bath, a Luttinger-liquid description is valid and the impurity suffers an Abraham-Lorentz radiation-reaction friction. For a large portion of the explored parameter space, the TDMRG results fall well beyond the Luttinger-liquid paradigm. PMID:23383804

  16. A One-Dimensional Magnet Based on [Mo(III)(CN)7](4.).

    PubMed

    Wei, Xiao-Qin; Qian, Kun; Wei, Hai-Yan; Wang, Xin-Yi

    2016-06-01

    Self-assembly of the [Mo(III)(CN)7](4-) anion and the Mn(II) unit with a macrocyclic ligand results in the first example of a one-dimensional (1D) chain compound based on the heptacyanomolybdate, [Mn(LN5C10)]2[Mo(CN)7]·2H2O (LN5C10 = 1,4,7,10,13-pentaazacyclopentadecane). Because of the existence of the interchain magnetic coupling, long-rang magnetic ordering was observed in this compound. PMID:27177390

  17. Theory of the optical conductivity of spin liquid states in one-dimensional Mott insulators.

    PubMed

    Katsura, Hosho; Sato, Masahiro; Furuta, Takashi; Nagaosa, Naoto

    2009-10-23

    The low-energy dynamical optical response of dimerized and undimerized spin liquid states in a one-dimensional charge transfer Mott insulator is theoretically studied. An exact analysis is given for the low-energy asymptotic behavior using conformal field theory for the undimerized state. In the dimerized state, the infrared absorption due to the bound state of two solitons, i.e., the breather mode, is predicted with an accurate estimate for its oscillator strength, offering a way to detect experimentally the excited singlet state. The effects of external magnetic fields are also discussed.

  18. Cold atoms in one-dimensional rings: a Luttinger liquid approach to precision measurement

    NASA Astrophysics Data System (ADS)

    Ragole, Stephen; Taylor, Jacob

    Recent experiments have realized ring shaped traps for ultracold atoms. We consider the one-dimensional limit of these ring systems with a moving weak barrier, such as a blue-detuned laser beam. In this limit, we employ Luttinger liquid theory and find an analogy with the superconducting charge qubit. In particular, we find that strongly-interacting atoms in such a system could be used for precision rotation sensing. We compare the performance of this new sensor to the state of the art non-interacting atom interferometry. Funding provided by the Physics Frontier Center at the JQI and by DARPA QUASAR.

  19. Relative stability of excitonic complexes in quasi-one-dimensional semiconductors

    NASA Astrophysics Data System (ADS)

    Bondarev, I. V.

    2014-12-01

    A configuration space approach is developed to uncover generic stability peculiarities for the lowest energy neutral and charged exciton complexes (biexciton and trion) in quasi-one-dimensional semiconductors. Trions are shown to be more stable than biexcitons in strongly confined structures with small reduced electron-hole masses. Biexcitons are more stable in less confined structures with large reduced electron-hole masses. In semiconducting carbon nanotubes, in particular, the trion binding energy is shown to be greater than that of the biexciton by a factor of ˜1.4 , decreasing with diameter, thus revealing the general physical principles that underlie recent experimental observations.

  20. Kink model of state switching in quasi-one-dimensional nanosystems

    SciTech Connect

    Petukhov, B. V.

    2015-03-15

    A method for the analytical calculation of the kinetics of state switching induced by external field in quasi-one-dimensional systems has been developed. This method is based on the Kolmogorov approach, which was proposed to describe statistical crystallization. As applied to magnetic systems, it allows one to calculate magnetization curves and hysteresis loops. The results of analytical calculation are confirmed by stochastic Monte Carlo simulation, which also makes it possible to find characteristics of mixed domain states formed as a result of the multiple cycling of the external field amplitude.

  1. A one-dimensional modeling study of carbonaceous haze effects on the springtime Arctic environment

    NASA Technical Reports Server (NTRS)

    Emery, Christopher A.; Haberle, Robert; Ackerman, Thomas P.

    1992-01-01

    The effect of carbonaceous Arctic haze on the surface energy balance was investigated using a specially developed one-dimensional three-component numerical model which accounts for the transfer of IR and solar radiation through the atmosphere, turbulent mixing within the boundary layer, and heat conduction through snow-capped sea ice. The results of calculations indicate that, when haze is present, the surface temperature increases, provided the relative humidity through the column does not change. The increase is due to an increase in the absorbed radiation at the surface.

  2. Analysis of cutoff frequency in a one-dimensional superconductor-metamaterial photonic crystal

    NASA Astrophysics Data System (ADS)

    Aly, Arafa H.; Aghajamali, Alireza; Elsayed, Hussein A.; Mobarak, Mohamed

    2016-09-01

    In this paper, using the two-fluid model and the characteristic matrix method, we investigate the transmission characteristics of the one-dimensional photonic crystal. Our structure composed of the layers of low-temperature superconductor material (NbN) and double-negative metamaterial. We target studying the effect of many parameters such as the thickness of the superconductor material, the thickness of the metamaterial layer, and the operating temperature. We show that the cut-off frequency can be tuned efficiently by the operating temperature as well as the thicknesses of the constituent materials.

  3. Discontinuous current-phase relations in small one-dimensional Josephson junction arrays.

    PubMed

    Koch, Jens; Le Hur, Karyn

    2008-08-29

    We study the Josephson effect in small one-dimensional (1D) Josephson junction arrays. For weak Josephson tunneling, topologically different regions in the charge-stability diagram generate distinct current-phase (I-phi) relationships. We present results for a three-junction system in the vicinity of charge-degeneracy lines and triple points. We explain the generalization to larger arrays, show that discontinuities of the I-phi relation at phase pi persist and that, at maximum degeneracy, the problem can be mapped to a tight-binding model providing analytical results for arbitrary system size.

  4. Studying non-equilibrium many-body dynamics using one-dimensional Bose gases

    SciTech Connect

    Langen, Tim; Gring, Michael; Kuhnert, Maximilian; Rauer, Bernhard; Geiger, Remi; Mazets, Igor; Smith, David Adu; Schmiedmayer, Jörg; Kitagawa, Takuya; Demler, Eugene

    2014-12-04

    Non-equilibrium dynamics of isolated quantum many-body systems play an important role in many areas of physics. However, a general answer to the question of how these systems relax is still lacking. We experimentally study the dynamics of ultracold one-dimensional (1D) Bose gases. This reveals the existence of a quasi-steady prethermalized state which differs significantly from the thermal equilibrium of the system. Our results demonstrate that the dynamics of non-equilibrium quantum many-body systems is a far richer process than has been assumed in the past.

  5. A quasi-one-dimensional model for the Giacobini-Zinner plasma tail

    SciTech Connect

    Malara, F. ); Einaudi, G. ); Mangeney, A. )

    1989-09-01

    An assumption of quasi-one-dimensionality is used to derive a simple set of equations describing the comet Giacobini-Zinner tail configuration. The MHD equations are expanded in terms of a parameter representing the ratio of the length scale in the direction perpendicular to the neutral sheet over the length scale in the direction parallel to the tail. It is shown that in this way it is possible to obtain much information on the structure of the tail and to fit reasonably well the observations made by the ICE spacecraft.

  6. A one-dimensional interactive soil-atmosphere model for testing formulations of surface hydrology

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Eagleson, Peter S.

    1990-01-01

    A model representing a soil-atmosphere column in a GCM is developed for off-line testing of GCM soil hydrology parameterizations. Repeating three representative GCM sensitivity experiments with this one-dimensional model demonstrates that, to first order, the model reproduces a GCM's sensitivity to imposed changes in parameterization and therefore captures the essential physics of the GCM. The experiments also show that by allowing feedback between the soil and atmosphere, the model improves on off-line tests that rely on prescribed precipitation, radiation, and other surface forcing.

  7. Design and fabrication of one-dimensional and two- dimensional photonic bandgap devices

    NASA Astrophysics Data System (ADS)

    Lim, Kuo-Yi

    1999-10-01

    One-dimensional and two-dimensional photonic bandgap devices have been designed and fabricated using III-V compound semiconductors. The one-dimensional photonic bandgap devices consist of monorail and air-bridge waveguide microcavities, while the two-dimensional photonic bandgap devices consist of light-emitting devices with enhanced extraction efficiency. Fabrication techniques such as gas source molecular beam epitaxy, direct-write electron-beam lithography, reactive ion etching and thermal oxidation of AlxGa1- xAs have been employed. The III-V thermal oxide, in particular, is used as an index confinement material, as a sacrificial material for micromechanical fabrication of the air-bridge microcavity, and in the realization of a wide-bandwidth distributed Bragg reflector. The one-dimensional photonic bandgap waveguide microcavities have been designed to operate in the wavelength regimes of 4.5 m m and 1.55 m m. The devices designed to operate in the 1.55 m m wavelength regime have been optically characterized. The transmission spectra exhibit resonances at around 1.55 m m and cavity quality factors (Q's) ranging from 136 to 334. The resonant modal volume is calculated to be about 0.056 m m3. Tunability in the resonance wavelengths has also been demonstrated by changing the size of the defect in the one-dimensional photonic crystal. The two-dimensional photonic bandgap light-emitting device consists of a In0.51Ga0.49P/In0.2Ga0.8As/In 0.51Ga0.49P quantum well emitting at 980nm with a triangular photonic lattice of holes in the top cladding layer of the quantum well. The photonic crystal prohibits the propagation of guided modes in the semiconductor, thus enhancing the extraction of light vertical to the light-emitting device. A wide-bandwidth GaAs/AlxOy distributed Bragg reflector mirror under the quantum well structure further enhances the extraction of light from the devices. The extraction efficiency of the two-dimensional photonic bandgap light-emitting device

  8. Stable One-Dimensional Dissipative Solitons in Complex Cubic-Quintic Ginzburg-Landau Equation

    NASA Astrophysics Data System (ADS)

    Aleksic, N. B.; Pavlovic, G.; Skarka, V.

    2007-11-01

    The generation and nonlinear dynamics of one-dimensional optical dissipative solitonic pulses are examined. The variational method is extended to complex dissipative systems, in order to obtain steady state solutions of the (1+1)-dimensional complex cubic-quintic Ginzburg-Landau equation. A stability criterion is established fixing a domain of dissipative parameters for stable steady state solutions. Following numerical simulations, evolution of any input pulse from this domain leads to stable dissipative temporal solitons. Analytical predictions are confirmed by numerical evolution of input temporal pulses towards stable dissipative solitons.

  9. Polymer-loaded propagating modes on a one-dimensional photonic crystal

    SciTech Connect

    Han, Lu; Zhang, Douguo Chen, Yikai; Wang, Ruxue; Zhu, Liangfu; Wang, Pei; Ming, Hai; Lakowicz, Joseph R.; Badugu, Ramachandram

    2014-02-10

    We numerically and experimentally demonstrate that a polymer film-coated one-dimensional photonic crystal (1DPC) can sustain transverse electric (TE) polarized modes without the limit of guided layer's thickness. Our results indicate that two propagating modes are existing inside the polymer film, the first one is the TE polarized Bloch surface wave, and the second one is the TE polarized guided mode. Here in, the evolution of these two modes with change in the polymer film thickness is presented. Our numerical simulation results are in well-agreement with the experimental data obtained using back focal plane imaging.

  10. Uniaxial magnetic anisotropy of quasi-one-dimensional Fe chains on Pb/Si

    SciTech Connect

    Sun, Da-li; Wang, De-yong; Du, Hai-Feng; Ning, Wei; Gao, Jian-Hua; Fang, Ya-Peng; Zhang, Xiang-Qun; Sun, Young; Cheng, Zhao-Hua; Shen, Jian

    2009-01-01

    We fabricated quasi-one-dimensional Fe chains on a 4{sup o} miscut Si (111) substrate with a Pb film as a buffer layer. The magnetic properties and morphology of Fe chains were investigated by means of scanning tunneling microscope (STM) and surface magneto-optical Kerr effect (SMOKE). STM images show that Fe chains are formed by Fe random islands along the steps of the Pb film due to step decoration. SMOKE data indicate that the Fe chains exhibit in-plane uniaxial magnetic anisotropy along the step direction. The effective in-plane uniaxial anisotropy constant at room temperature was determined by means of electron spin resonance.

  11. One-dimensional quantum liquids with power-law interactions: the Luttinger staircase.

    PubMed

    Dalmonte, M; Pupillo, G; Zoller, P

    2010-10-01

    We study one-dimensional fermionic and bosonic gases with repulsive power-law interactions 1/|x|(β), with β>1, in the framework of Tomonaga-Luttinger liquid (TLL) theory. We obtain an accurate analytical expression linking the TLL parameter to the microscopic Hamiltonian, for arbitrary β and strength of the interactions. In the presence of a small periodic potential, power-law interactions make the TLL unstable towards the formation of a cascade of lattice solids with fractional filling, a "Luttinger staircase." Several of these quantum phases and phase transitions are realized with ground state polar molecules and weakly bound magnetic Feshbach molecules.

  12. One-Dimensional Quantum Liquids with Power-Law Interactions: The Luttinger Staircase

    SciTech Connect

    Dalmonte, M.; Pupillo, G.; Zoller, P.

    2010-10-01

    We study one-dimensional fermionic and bosonic gases with repulsive power-law interactions 1/|x|{sup {beta}}, with {beta}>1, in the framework of Tomonaga-Luttinger liquid (TLL) theory. We obtain an accurate analytical expression linking the TLL parameter to the microscopic Hamiltonian, for arbitrary {beta} and strength of the interactions. In the presence of a small periodic potential, power-law interactions make the TLL unstable towards the formation of a cascade of lattice solids with fractional filling, a 'Luttinger staircase'. Several of these quantum phases and phase transitions are realized with ground state polar molecules and weakly bound magnetic Feshbach molecules.

  13. Numerical studies of variable-range hopping in one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Rodin, A. S.; Fogler, M. M.

    2010-03-01

    We report on our recent numerical study [1] of hopping transport in disordered one-dimensional systems. A fast new algorithm, based on Dijkstra shortest-path algorithm, is devised to find the lowest-resistance path through the hopping network at arbitrary electric field. Probability distribution functions of individual resistances on the path and the net resistance are calculated and fitted to compact analytic formulas. Qualitative differences between statistics of resistance fluctuations in Ohmic and non-Ohmic regimes are elucidated. The results are compared with prior theoretical and experimental work on the subject.[6pt] [1] A. S. Rodin and M. M. Fogler, Phys. Rev. B 80, 155435 (2009).

  14. Effects of interaction symmetry on delocalization and energy transport in one-dimensional disordered lattices

    NASA Astrophysics Data System (ADS)

    Wang, Jianjin; He, Dahai; Zhang, Yong; Wang, Jiao; Zhao, Hong

    2015-09-01

    We study effects of interaction symmetry in one-dimensional, momentum-conserving disordered lattices. It is found that asymmetric and symmetric interparticle interactions may result in significant difference: localized modes can be delocalized by very weak asymmetric interactions but survive much stronger symmetric interactions. Moreover, in the delocalization regime, asymmetric and symmetric interactions also have qualitatively different effects on transport: the former (the latter) may lead to a fast decaying (slow power-law decaying) heat current correlation function and in turn a convergent (divergent) heat conductivity. A method for detecting delocalization in systems at a nonzero temperature is proposed as well.

  15. A Study on Propagation Characteristic of One-dimensional Stress Wave in Functionally Graded Armor Composites

    NASA Astrophysics Data System (ADS)

    Yang, S. Y.; Liu, X.; Cao, D. F.; Mei, H.; Lei, Z. T.; Liu, L. S.

    2013-03-01

    The development of Functionally Graded Materials (FGM) for energy-absorbing applications requires understanding of stress wave propagation in these structures in order to optimize their resistance to failure. One-dimensional stress wave in FGM composites under elastic and plastic wave loading have been investigated. The stress distributions through the thickness and stress status have been analyzed and some comparisons have been done with the materials of sharp interfaces (two-layered material). The results demonstrate that the gradient structure design greatly decreases the severity of the stress concentrations at the interfaces and there are no clear differences in stress distribution in FGM composites under elastic and plastic wave loading.

  16. Nonlinear instability of the one-dimensional Vlasov-Yukawa system

    SciTech Connect

    Ha, Seung-Yeal; Lee, Ho; Ha, Taeyoung; Hwang, Chi-Ok

    2011-03-15

    We discuss the nonlinear instability of some class of stationary solutions to the one-dimensional Vlasov-Yukawa system with a mass parameter m. The Vlasov-Yukawa system corresponds to the short-range correction of the repulsive Vlasov-Poisson system arising from plasma physics. We show that the stationary solutions satisfying the Penrose condition are nonlinearly unstable in small mass regime. In a large mass regime, the massiveness of force carrier particles acts as stabilizer in a finite time interval. We present several numerical results to confirm our analytical results.

  17. Quasi-One-Dimensional Particle-in-Cell Simulation of Magnetic Nozzles

    NASA Technical Reports Server (NTRS)

    Ebersohn, Frans H.; Sheehan, J. P.; Gallimore, Alec D.; Shebalin, John V.

    2015-01-01

    A method for the quasi-one-dimensional simulation of magnetic nozzles is presented and simulations of a magnetic nozzle are performed. The effects of the density variation due to plasma expansion and the magnetic field forces on ion acceleration are investigated. Magnetic field forces acting on the electrons are found to be responsible for the formation of potential structures which accelerate ions. The effects of the plasma density variation alone are found to only weakly affect ion acceleration. Strongly diverging magnetic fields drive more rapid potential drops.

  18. Disorder-induced transparency in a one-dimensional waveguide side coupled with optical cavities

    SciTech Connect

    Zhang, Yongyou Dong, Guangda; Zou, Bingsuo

    2014-05-07

    Disorder influence on photon transmission behavior is theoretically studied in a one-dimensional waveguide side coupled with a series of optical cavities. For this sake, we propose a concept of disorder-induced transparency appearing on the low-transmission spectral background. Two kinds of disorders, namely, disorders of optical cavity eigenfrequencies and relative phases in the waveguide side coupled with optical cavities are considered to show the disorder-induced transparency. They both can induce the optical transmission peaks on the low-transmission backgrounds. The statistical mean value of the transmission also increases with increasing the disorders of the cavity eigenfrequencies and relative phases.

  19. Superfluid--Insulator Transition in Commensurate One-Dimensional Bosonic System with Off-Diagonal Disorder

    NASA Astrophysics Data System (ADS)

    Balabanyan, Karén; Prokof'ev, Nikolay; Svistunov, Boris

    2005-03-01

    We analyze the superfluid--insulator transition in a system of one-dimensional (1D) lattice bosons with off-diagonal disorder in the limit of large commensurate filling. We argue---in contrast to the recent prediction (E. Altman, Y. Kafri, A. Polkovnikov, and G. Refael, cond-mat/0402177) of strong- randomness fixed point for this system---that at any strength of disorder the universality class of the transition on the superfluid side coincides with that of the superfluid--Mott- insulator transition in a pure system. We present results of Monte Carlo simulations for two strongly disordered models that are in excellent agreement with the advocated scenario.

  20. One-dimensional numerical analysis of the transient thermal response of multilayer insulative systems

    NASA Technical Reports Server (NTRS)

    Pittman, C. M.; Brinkley, K. L.

    1976-01-01

    A one-dimensional numerical analysis of the transient thermal response of multilayer insulative systems has been developed. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a vehicle and determine total system mass.

  1. Analysis of the transient calibration of heat flux sensors: One dimensional case

    NASA Technical Reports Server (NTRS)

    Dybbs, A.; Ling, J. X.

    1989-01-01

    The effect of transient heat flux on heat flux sensor response and calibration is analyzed. A one dimensional case was studied in order to elucidate the key parameters and trends for the problem. It has the added advantage that the solutions to the governing equations can be obtained by analytic means. The analytical results obtained to date indicate that the transient response of a heat flux sensor depends on the thermal boundary conditions, the geometry and the thermal properties of the sensor. In particular it was shown that if the thermal diffusivity of the sensor is small, then the transient behavior must be taken into account.

  2. Phononic heat transfer through a one dimensional system subject to two sources of nonequilibrium

    NASA Astrophysics Data System (ADS)

    Beraha, N.; Soba, A.; Barreto, R.; Carusela, M. F.

    2015-09-01

    We analyze the energy transport in a one dimensional chain composed by two Frenkel-Kontorova (FK) segments connected together by a time modulated coupling. The ends are immersed in two thermal reservoirs with oscillating temperatures. We observe a single and multiresonant heat transport depending on the regimes considered, with a crossover between a mechanical resonance and a thermodynamical resonance. The dynamical tuning between these two regimes requires the synergetic presence of both time dependent sources of nonequilibrium. In the single resonant regime we analyze a "red shifted" resonant frequency that is dependent on the size of the system.

  3. Electron Supercollimation in Graphene and Dirac Fermion Materials Using One-Dimensional Disorder Potentials

    NASA Astrophysics Data System (ADS)

    Choi, SangKook; Park, Cheol-Hwan; Louie, Steven G.

    2014-07-01

    Electron supercollimation, in which a wave packet is guided to move undistorted along a selected direction, is a highly desirable property that has yet to be realized experimentally. Disorder in general is expected to inhibit supercollimation. Here we report a counterintuitive phenomenon of electron supercollimation by disorder in graphene and related Dirac fermion materials. We show that one can use one-dimensional disorder potentials to control electron wave packet transport. This is distinct from known systems where an electron wave packet would be further spread by disorder and hindered in the potential fluctuating direction. The predicted phenomenon has significant implications in the understanding and applications of electron transport in Dirac fermion materials.

  4. Hidden-symmetry-protected topological phases on a one-dimensional lattice

    NASA Astrophysics Data System (ADS)

    Li, Linhu; Chen, Shu

    2015-02-01

    We demonstrate the existence of a topologically nontrivial phase in a one-dimensional fermionic lattice system subjected to synthetic gauge fields, which is beyond the standard Altland-Zirnbauer classification of topological insulators. The topological phase can be characterized by the presence of degenerate zero-mode edge states or a quantized Berry phase of the occupied Bloch band. By analyzing symmetries of the system, we identify that the topological phase and zero-mode edge states are protected by two hidden symmetries. An extended model with hidden symmetry breaking is also studied in order to reveal the effect of hidden symmetries on the symmetry-protected topological phase.

  5. Fulde-Ferrell-Larkin-Ovchinnikov critical polarization in one-dimensional fermionic optical lattices

    NASA Astrophysics Data System (ADS)

    França, Vivian V.; Hörndlein, Dominik; Buchleitner, Andreas

    2012-09-01

    We deduce an expression for the critical polarization PC below which the Fulde-Ferrell-Larkin-Ovchinnikov state emerges in one-dimensional lattices with spin-imbalanced populations. We provide and explore the phase diagram of unconfined chains as a function of polarization, interaction, and particle density. For harmonically confined systems, we supply a quantitative mapping, which also allows applying our phase diagram for confined chains. We find analytically and confirm numerically that the upper bound for the critical polarization is universal: PCmax=1/3 for any density, interaction, and confinement strength.

  6. Transport properties of coupled one-dimensional interacting electron systems with impurities

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kuroki, Kazuhiko; Aoki, Hideo

    1995-05-01

    We consider two one-dimensional interacting electron systems that are coupled via interchain tunneling to calculate transport properties in the presence of impurities or a single barrier by using the bosonization formalisms for the non-Luttinger-liquid phases on the phase diagram obtained by Fabrizio [Phys. Rev. B 48, 15 838 (1993)]. We find for the weak- and strong-interaction phases, where the superconducting correlation dominates in the ground state, that the interchain transfer enhances the conductivity and the Anderson localization is suppressed. This shows that multichain systems can have unique transport properties.

  7. Observation of localized flat-band modes in a quasi-one-dimensional photonic rhombic lattice.

    PubMed

    Mukherjee, Sebabrata; Thomson, Robert R

    2015-12-01

    We experimentally demonstrate the photonic realization of a dispersionless flat band in a quasi-one-dimensional photonic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation, the lattice supports two dispersive and one nondispersive (flat) band. We experimentally excite superpositions of flat-band eigenmodes at the input of the photonic lattice and show the diffractionless propagation of the input states due to their infinite effective mass. In the future, the use of photonic rhombic lattices, together with the successful implementation of a synthetic gauge field, will enable the observation of Aharonov-Bohm photonic caging.

  8. Global Solvability of the One-Dimensional Cosserat-Bingham Fluid Equations

    NASA Astrophysics Data System (ADS)

    Shelukhin, V. V.; Chemetov, N. V.

    2015-09-01

    The equations for micropolar Bingham fluid are considered and global existence of a weak solution for pressure driven flows is proved for a one-dimensional boundary-value problem with periodic boundary conditions. In contrast to the classical Bingham fluid, the micropolar Bingham fluid supports local micro-rotations and two types of plug zones. Our approach is different from that of Duvaut-Lions developed for the classical Bingham viscoplastic materials. We do not apply the variational inequality but make use an approximation of the generalized Bingham fluid by a Non-Newtonian fluid with a continuous constitutive law.

  9. On the one-dimensional acoustic propagation in conical ducts with stationary mean flow.

    PubMed

    Barjau, Ana

    2007-12-01

    This paper proposes a direct time-domain calculation of the time-domain responses of anechoic conical tubes with steady weak mean flow. The starting point is the approximated linear one-dimensional wave equation governing the velocity potential for the case of steady flow with low Mach number. A traveling solution with general space-dependent propagation velocity is then proposed from which the inward and outward pressure and velocity impulse responses can be obtained. The results include the well-known responses of conical and cylindrical ducts with zero mean flow.

  10. Synthesis and integration of one-dimensional nanostructures for chemical gas sensing applications

    NASA Astrophysics Data System (ADS)

    Parthangal, Prahalad Madhavan

    The need for improved measurement technology for the detection and monitoring of gases has increased tremendously for maintenance of domestic and industrial health and safety, environmental surveys, national security, food-processing, medical diagnostics and various other industrial applications. Among the several varieties of gas sensors available in the market, solid-state sensors are the most popular owing to their excellent sensitivity, ruggedness, versatility and low cost. Semiconducting metal oxides such as tin oxide (SnO2), zinc oxide (ZnO), and tungsten oxide (WO3) are routinely employed as active materials in these sensors. Since their performance is directly linked to the exposed surface area of the sensing material, one-dimensional nanostructures possessing very high surface to volume ratios are attractive candidates for designing the next generation of sensors. Such nano-sensors also enable miniaturization thereby reducing power consumption. The key to achieve success in one-dimensional nanotechnologies lies in assembly. While synthesis techniques and capabilities continue to expand rapidly, progress in controlled assembly has been sluggish due to numerous technical challenges. In this doctoral thesis work, synthesis and characterization of various one-dimensional nanostructures including nanotubes of SnO2, and nanowires of WO3 and ZnO, as well as their direct integration into miniature sensor platforms called microhotplates have been demonstrated. The key highlights of this research include devising elegant strategies for growing metal oxide nanotubes using carbon nanotubes as templates, substantially reducing process temperatures to enable growth of WO3 nanowires on microhotplates, and successfully fabricating a ZnO nanowire array based sensor using a hybrid nanowire-nanoparticle assembly approach. In every process, the gas-sensing properties of one-dimensional nanostructures were observed to be far superior in comparison with thin films of the same

  11. Pseudo one-dimensional analysis of polymer electrolyte fuel cell cold-start

    SciTech Connect

    Mukherjee, Partha P; Mukundan, Rangachary; Borup, Rodney L; Wang, Yun; Mishlera, Jeff

    2009-01-01

    This paper investigates the electrochemical kinetics, oxygen transport, and solid water formation in polymer electrolyte fuel cell (PEFC) during cold start. Following [Yo Wang, J. Electrochem. Soc., 154 (2007) B1041-B1048], we develop a pseudo one-dimensional analysis, which enables the evaluation of the impact of ice volume fraction and temperature variations on cell performance during cold-start. The oxygen profile, starvation ice volume fraction, and relevant overpotentials are obtained. This study is valuable for studying the characteristics of PEFC cold-start.

  12. Hydrogen atom trapping in a self-organized one-dimensional dimer

    SciTech Connect

    Takami, Tsuyoshi; Kawamura, Kazushi

    2014-09-01

    Metal–organic frameworks (MOFs) have attracted widespread attention owing to their unusual structure and properties produced by their nanospaces. However, many MOFs possess the similar three-dimensional frameworks, limiting their structural variety and operating capacity for hydrogen storage under ambient conditions. Here we report the synthesis and structural characterization of a single-crystal one-dimensional dimer whose structure, operating capacity, and physical mechanism contrast with those of existing MOFs. The hydrogen storage capacity of 2.6 wt.% is comparable to the highest capacity achieved by existing MOFs at room temperature. This exceptional storage capacity is realized by self-organization during crystal growth using a weak base.

  13. Green's functions of one-dimensional quasicrystal bi-material with piezoelectric effect

    NASA Astrophysics Data System (ADS)

    Zhang, Liangliang; Wu, Di; Xu, Wenshuai; Yang, Lianzhi; Ricoeur, Andreas; Wang, Zhibin; Gao, Yang

    2016-09-01

    Based on the Stroh formalism of one-dimensional quasicrystals with piezoelectric effect, the problems of an infinite plane composed of two different quasicrystal half-planes are taken into account. The solutions of the internal and interfacial Green's functions of quasicrystal bi-material are obtained. Moreover, numerical examples are analyzed for a quasicrystal bi-material subjected to line forces or line dislocations, showing the contour maps of the coupled fields. The impacts of changing material constants on the coupled field components are investigated.

  14. Phase separation and pairing regimes in the one-dimensional asymmetric Hubbard model

    SciTech Connect

    Barbiero, L.; Casadei, M.; Dalmonte, M.; Ercolessi, E.; Ortolani, F.

    2010-06-01

    We address some open questions regarding the phase diagram of the one-dimensional Hubbard model with asymmetric hopping coefficients and balanced species. In the attractive regime we present a numerical study of the passage from on-site pairing dominant correlations at small asymmetries to charge-density waves in the region with markedly different hopping coefficients. In the repulsive regime we exploit two analytical treatments in the strong- and weak-coupling regimes in order to locate the onset of phase separation at small and large asymmetries, respectively.

  15. Gas Sensors Based on Semiconducting Metal Oxide One-Dimensional Nanostructures

    PubMed Central

    Huang, Jin; Wan, Qing

    2009-01-01

    This article provides a comprehensive review of recent (2008 and 2009) progress in gas sensors based on semiconducting metal oxide one-dimensional (1D) nanostructures. During last few years, gas sensors based on semiconducting oxide 1D nanostructures have been widely investigated. Additionally, modified or doped oxide nanowires/nanobelts have also been synthesized and used for gas sensor applications. Moreover, novel device structures such as electronic noses and low power consumption self-heated gas sensors have been invented and their gas sensing performance has also been evaluated. Finally, we also point out some challenges for future investigation and practical application. PMID:22303154

  16. Pulse trapping inside a one-dimensional photonic crystal with relaxing cubic nonlinearity

    SciTech Connect

    Novitsky, Denis V.

    2010-05-15

    We theoretically study the effect of pulse trapping inside one-dimensional photonic crystal with relaxing cubic nonlinearity. We analyze dependence of light localization on pulse intensity and explain its physical mechanism as connected with the formation of a dynamical nonlinear cavity inside the structure. We search for the range of optimal values of parameters (relaxation time and pulse duration) and show that pulse trapping can be observed only for positive nonlinearity coefficients. We suppose that this effect can be useful for realization of optical memory and limiting.

  17. The controlled synthesis of polyglucose in one-dimensional coordination nanochannels.

    PubMed

    Kobayashi, Yuichiro; Horie, Yuki; Honjo, Kayako; Uemura, Takashi; Kitagawa, Susumu

    2016-04-14

    We demonstrate a feasible method for the preparation of polyglucose (PGlc) with controlled structures, where the polymerization of glucose monomers was performed using one-dimensional nanochannels of [La(1,3,5-benzenetrisbenzoate)(H2O)]n (1). Cationic ring-opening polymerization of 1,6-anhydro-β-D-glucose (levoglucosan) using 1 gave a quasi-linear PGlc, which contrasts highly with the results obtained from conventional polymerizations in bulk and solution. The regulated structure of PGlc prepared using the PCP led to a remarkable improvement in the processability and thermal stability of PGlc, which is useful in applications as a bioplastic. PMID:26996883

  18. Electric Field Guided Assembly of One-Dimensional Nanostructures for High Performance Sensors

    PubMed Central

    Brown, Devon A.; Kim, Jong-Hoon; Lee, Hyun-Boo; Fotouhi, Gareth; Lee, Kyong-Hoon; Liu, Wing Kam; Chung, Jae-Hyun

    2012-01-01

    Various nanowire or nanotube-based devices have been demonstrated to fulfill the anticipated future demands on sensors. To fabricate such devices, electric field-based methods have demonstrated a great potential to integrate one-dimensional nanostructures into various forms. This review paper discusses theoretical and experimental aspects of the working principles, the assembled structures, and the unique functions associated with electric field-based assembly. The challenges and opportunities of the assembly methods are addressed in conjunction with future directions toward high performance sensors. PMID:22778610

  19. A Ubiquitiformal One-Dimensional Steady-State Conduction Model for a Cellular Material Rod

    NASA Astrophysics Data System (ADS)

    Li, Guan-Ying; Ou, Zhuo-Cheng; Xie, Ran; Duan, Zhuo-Ping; Huang, Feng-Lei

    2016-04-01

    A ubiquitiformal model for the one-dimensional steady-state heat transfer of a cellular material rod is developed in this paper, and the explicit analytical expressions for both the temperature distribution and the equivalent thermal conductivity are obtained. The calculated results for two kinds of dry soil are found to be in good agreement with previous experimental data. Moreover, it is demonstrated that the ubiquitiformal model is more reasonable for describing such a cellular material than the fractal one, and hence a ubiquitiformal rather than a fractal model should be considered in practical applications whenever the integral dimensional measure of a real physical object must be taken into account.

  20. Communication: HK propagator uniformized along a one-dimensional manifold in weakly anharmonic systems

    SciTech Connect

    Kocia, Lucas Heller, Eric J.

    2014-11-14

    A simplification of the Heller-Herman-Kluk-Kay (HK) propagator is presented that does not suffer from the need for an increasing number of trajectories with dimensions of the system under study. This is accomplished by replacing HK’s uniformizing integral over all of phase space by a one-dimensional curve that is appropriately selected to lie along the fastest growing manifold of a defining trajectory. It is shown that this modification leads to eigenspectra of quantum states in weakly anharmonic systems that can outperform the comparatively computationally cheap thawed Gaussian approximation method and frequently approach the accuracy of spectra obtained with the full HK propagator.