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Sample records for dipolar coupling based

  1. Determination of structural fluctuations of proteins from structure-based calculations of residual dipolar couplings

    International Nuclear Information System (INIS)

    Montalvao, Rinaldo W.; De Simone, Alfonso; Vendruscolo, Michele

    2012-01-01

    Residual dipolar couplings (RDCs) have the potential of providing detailed information about the conformational fluctuations of proteins. It is very challenging, however, to extract such information because of the complex relationship between RDCs and protein structures. A promising approach to decode this relationship involves structure-based calculations of the alignment tensors of protein conformations. By implementing this strategy to generate structural restraints in molecular dynamics simulations we show that it is possible to extract effectively the information provided by RDCs about the conformational fluctuations in the native states of proteins. The approach that we present can be used in a wide range of alignment media, including Pf1, charged bicelles and gels. The accuracy of the method is demonstrated by the analysis of the Q factors for RDCs not used as restraints in the calculations, which are significantly lower than those corresponding to existing high-resolution structures and structural ensembles, hence showing that we capture effectively the contributions to RDCs from conformational fluctuations.

  2. DipoCoup: A versatile program for 3D-structure homology comparison based on residual dipolar couplings and pseudocontact shifts

    International Nuclear Information System (INIS)

    Meiler, Jens; Peti, Wolfgang; Griesinger, Christian

    2000-01-01

    A program, DipoCoup, is presented that allows to search the protein data bank for proteins which have a three dimensional fold that is at least partially homologous to a protein under investigation. The three dimensional homology search uses secondary structure alignment based on chemical shifts and dipolar couplings or pseudocontact shifts for the three dimensional orientation of secondary structure elements. Moreover, the program offers additional tools for handling and analyzing dipolar couplings

  3. Protein resonance assignment at MAS frequencies approaching 100 kHz: a quantitative comparison of J-coupling and dipolar-coupling-based transfer methods

    Energy Technology Data Exchange (ETDEWEB)

    Penzel, Susanne; Smith, Albert A.; Agarwal, Vipin; Hunkeler, Andreas [ETH Zürich, Physical Chemistry (Switzerland); Org, Mai-Liis; Samoson, Ago, E-mail: ago.samoson@ttu.ee [Tallinn University of Technology, NMR Instituut, Tartu Teadus, Tehnomeedikum (Estonia); Böckmann, Anja, E-mail: a.bockmann@ibcp.fr [UMR 5086 CNRS/Université de Lyon 1, Institut de Biologie et Chimie des Protéines (France); Ernst, Matthias, E-mail: maer@ethz.ch; Meier, Beat H., E-mail: beme@ethz.ch [ETH Zürich, Physical Chemistry (Switzerland)

    2015-10-15

    We discuss the optimum experimental conditions to obtain assignment spectra for solid proteins at magic-angle spinning (MAS) frequencies around 100 kHz. We present a systematic examination of the MAS dependence of the amide proton T{sub 2}′ times and a site-specific comparison of T{sub 2}′ at 93 kHz versus 60 kHz MAS frequency. A quantitative analysis of transfer efficiencies of building blocks, as they are used for typical 3D experiments, was performed. To do this, we compared dipolar-coupling and J-coupling based transfer steps. The building blocks were then combined into 3D experiments for sequential resonance assignment, where we evaluated signal-to-noise ratio and information content of the different 3D spectra in order to identify the best assignment strategy. Based on this comparison, six experiments were selected to optimally assign the model protein ubiquitin, solely using spectra acquired at 93 kHz MAS. Within 3 days of instrument time, the required spectra were recorded from which the backbone resonances have been assigned to over 96 %.

  4. Exact solutions for chemical bond orientations from residual dipolar couplings

    International Nuclear Information System (INIS)

    Wedemeyer, William J.; Rohl, Carol A.; Scheraga, Harold A.

    2002-01-01

    New methods for determining chemical structures from residual dipolar couplings are presented. The fundamental dipolar coupling equation is converted to an elliptical equation in the principal alignment frame. This elliptical equation is then combined with other angular or dipolar coupling constraints to form simple polynomial equations that define discrete solutions for the unit vector(s). The methods are illustrated with residual dipolar coupling data on ubiquitin taken in a single anisotropic medium. The protein backbone is divided into its rigid groups (namely, its peptide planes and C α frames), which may be solved for independently. A simple procedure for recombining these independent solutions results in backbone dihedral angles φ and ψ that resemble those of the known native structure. Subsequent refinement of these φ-ψ angles by the ROSETTA program produces a structure of ubiquitin that agrees with the known native structure to 1.1 A C α rmsd

  5. Coherent manipulation of dipolar coupled spins in an anisotropic environment

    Science.gov (United States)

    Baibekov, E. I.; Gafurov, M. R.; Zverev, D. G.; Kurkin, I. N.; Malkin, B. Z.; Barbara, B.

    2014-11-01

    We study coherent dynamics in a system of dipolar coupled spin qubits diluted in a solid and subjected to a driving microwave field. In the case of rare earth ions, an anisotropic crystal background results in anisotropic g tensor and thus modifies the dipolar coupling. We develop a microscopic theory of spin relaxation in a transient regime for the frequently encountered case of axially symmetric crystal field. The calculated decoherence rate is nonlinear in the Rabi frequency. We show that the direction of a static magnetic field that corresponds to the highest spin g factor is preferable in order to obtain a higher number of coherent qubit operations. The results of calculations are in excellent agreement with our experimental data on Rabi oscillations recorded for a series of CaW O4 crystals with different concentrations of N d3 + ions.

  6. A new approach for applying residual dipolar couplings as restraints in structure elucidation

    International Nuclear Information System (INIS)

    Meiler, Jens; Blomberg, Niklas; Nilges, Michael; Griesinger, Christian

    2000-01-01

    Residual dipolar couplings are useful global structural restraints. The dipolar couplings define the orientation of a vector with respect to the alignment tensor. Although the size of the alignment tensor can be derived from the distribution of the experimental dipolar couplings, its orientation with respect to the coordinate system of the molecule is unknown at the beginning of structure determination. This causes convergence problems in the simulated annealing process. We therefore propose a protocol that translates dipolar couplings into intervector projection angles, which are independent of the orientation of the alignment tensor with respect to the molecule. These restraints can be used during the whole simulated annealing protocol

  7. Self-consistent residual dipolar coupling based model-free analysis for the robust determination of nanosecond to microsecond protein dynamics

    International Nuclear Information System (INIS)

    Lakomek, Nils-Alexander; Walter, Korvin F. A.; Fares, Christophe; Lange, Oliver F.; Groot, Bert L. de; Grubmueller, Helmut; Brueschweiler, Rafael; Munk, Axel; Becker, Stefan; Meiler, Jens; Griesinger, Christian

    2008-01-01

    Residual dipolar couplings (RDCs) provide information about the dynamic average orientation of inter-nuclear vectors and amplitudes of motion up to milliseconds. They complement relaxation methods, especially on a time-scale window that we have called supra-τ c (τ c c rdc > = 0.72 ± 0.02 compared to LS 2 > = 0.778 ± 0.003 for the Lipari-Szabo order parameters, indicating that the inclusion of the supra-τ c window increases the averaged amplitude of mobility observed in the sub-τ c window by about 34%. For the β-strand spanned by residues Lys48 to Leu50, an alternating pattern of backbone NH RDC order parameter S rdc 2 (NH) = (0.59, 0.72, 0.59) was extracted. The backbone of Lys48, whose side chain is known to be involved in the poly-ubiquitylation process that leads to protein degradation, is very mobile on the supra-τ c time scale (S rdc 2 (NH) = 0.59 ± 0.03), while it is inconspicuous (S LS 2 (NH) = 0.82) on the sub-τ c as well as on μs-ms relaxation dispersion time scales. The results of this work differ from previous RDC dynamics studies of ubiquitin in the sense that the results are essentially independent of structural noise providing a much more robust assessment of dynamic effects that underlie the RDC data

  8. Induced alignment and measurement of dipolar couplings of an SH2 domain through direct binding with filamentous phage

    International Nuclear Information System (INIS)

    Dahlke Ojennus, Deanna; Mitton-Fry, Rachel M.; Wuttke, Deborah S.

    1999-01-01

    Large residual 15 N- 1 H dipolar couplings have been measured in a Src homology II domain aligned at Pf1 bacteriophage concentrations an order of magnitude lower than used for induction of a similar degree of alignment of nucleic acids and highly acidic proteins. An increase in 1 H and 15 N protein linewidths and a decrease in T 2 and T 1 ρ relaxation time constants implicates a binding interaction between the protein and phage as the mechanism of alignment. However, the associated increased linewidth does not preclude the accurate measurement of large dipolar couplings in the aligned protein. A good correlation is observed between measured dipolar couplings and predicted values based on the high resolution NMR structure of the SH2 domain. The observation of binding-induced protein alignment promises to broaden the scope of alignment techniques by extending their applicability to proteins that are able to interact weakly with the alignment medium

  9. Structure refinement of flexible proteins using dipolar couplings: Application to the protein p8MTCP1

    International Nuclear Information System (INIS)

    Demene, Helene; Ducat, Thierry; Barthe, Philippe; Delsuc, Marc-Andre; Roumestand, Christian

    2002-01-01

    The present study deals with the relevance of using mobility-averaged dipolar couplings for the structure refinement of flexible proteins. The 68-residue protein p8 MTCP1 has been chosen as model for this study. Its solution state consists mainly of three α-helices. The two N-terminal helices are strapped in a well-determined α-hairpin, whereas, due to an intrinsic mobility, the position of the third helix is less well defined in the NMR structure. To further characterize the degrees of freedom of this helix, we have measured the dipolar coupling constants in the backbone of p8 MTCP1 in a bicellar medium. We show here that including D HN dip dipolar couplings in the structure calculation protocol improves the structure of the α-hairpin but not the positioning of the third helix. This is due to the motional averaging of the dipolar couplings measured in the last helix. Performing two calculations with different force constants for the dipolar restraints highlights the inconstancy of these mobility-averaged dipolar couplings. Alternatively, prior to any structure calculations, comparing the values of the dipolar couplings measured in helix III to values back-calculated from an ideal helix demonstrates that they are atypical for a helix. This can be partly attributed to mobility effects since the inclusion of the 15 N relaxation derived order parameter allows for a better fit

  10. Characterization of surfactant liquid crystal phases suitable for molecular alignment and measurement of dipolar couplings

    International Nuclear Information System (INIS)

    Barrientos, Laura G.; Dolan, Caroline; Gronenborn, Angela M.

    2000-01-01

    Media employed for imparting partial alignment onto solute molecules have recently attracted considerable attention, since they permit the measurement of NMR parameters for solute biomolecules commonly associated with solid state NMR. Here we characterize a medium which is based on a quasi-ternary surfactant system comprising cetylpyridinium bromide/hexanol/sodium bromide. We demonstrate that dilute solutions of this system can exist in liquid crystalline phases which orient in the magnetic field and allow the measurement of residual dipolar couplings under a variety of conditions. The present system is extremely versatile and robust, tolerating different buffer conditions, temperature ranges and concentrations

  11. A liquid crystalline medium for measuring residual dipolar couplings over a wide range of temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hong; Eberstadt, Matthias; Olejniczak, Edward T.; Meadows, Robert P.; Fesik, Stephen W. [Abbott Laboratories (United States)

    1998-10-15

    A mixture of dilauroyl phosphatidylcholine (DLPC) and 3-(cholamidopropyl)dimethylammonio-2-hydroxyl-1-propane sulfonate (CHAPSO) in water forms disc shaped bicelles that become ordered at high magnetic fields over a wide range of temperatures. As illustrated for the FK506 binding protein (FKBP), large residual dipolar couplings can be measured for proteins dissolved in low concentrations (5% w/v) of a DLPC/CHAPSO medium at a molar ratio of 4.2:1. This system is especially useful for measuring residual dipolar couplings for molecules that are only stable at low temperatures.

  12. A Refined Model for the Structure of Acireductone Dioxygenase from Klebsiella ATCC 8724 Incorporating Residual Dipolar Couplings

    Energy Technology Data Exchange (ETDEWEB)

    Pochapsky, Thomas C., E-mail: pochapsk@brandeis.edu; Pochapsky, Susan S.; Ju Tingting [Brandeis University, Department of Chemistry (United States); Hoefler, Chris [Brandeis University, Department of Biochemistry (United States); Liang Jue [Brandeis University, Department of Chemistry (United States)

    2006-02-15

    Acireductone dioxygenase (ARD) from Klebsiella ATCC 8724 is a metalloenzyme that is capable of catalyzing different reactions with the same substrates (acireductone and O{sub 2}) depending upon the metal bound in the active site. A model for the solution structure of the paramagnetic Ni{sup 2+}-containing ARD has been refined using residual dipolar couplings (RDCs) measured in two media. Additional dihedral restraints based on chemical shift (TALOS) were included in the refinement, and backbone structure in the vicinity of the active site was modeled from a crystallographic structure of the mouse homolog of ARD. The incorporation of residual dipolar couplings into the structural refinement alters the relative orientations of several structural features significantly, and improves local secondary structure determination. Comparisons between the solution structures obtained with and without RDCs are made, and structural similarities and differences between mouse and bacterial enzymes are described. Finally, the biological significance of these differences is considered.

  13. Residual dipolar couplings : a new technique for structure determination of proteins in solution

    NARCIS (Netherlands)

    van Lune, Frouktje Sapke

    2004-01-01

    The aim of the work described in this thesis was to investigate how residual dipolar couplings can be used to resolve or refine the three-dimensional structure of one of the proteins of the phosphoenol-pyruvate phosphotransferase system (PTS), the main transport system for carbohydrates in

  14. Improvement of hydrogen bond geometry in protein NMR structures by residual dipolar couplings - an assessment of the interrelation of NMR restraints

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Pernille Rose; Axelsen, Jacob Bock [University of Copenhagen, Institute of Molecular Biology (Denmark); Lerche, Mathilde Hauge [Amersham Health (Sweden); Poulsen, Flemming M. [University of Copenhagen, Institute of Molecular Biology (Denmark)], E-mail: fmp@apk.molbio.ku.dk

    2004-01-15

    We have examined how the hydrogen bond geometry in three different proteins is affected when structural restraints based on measurements of residual dipolar couplings are included in the structure calculations. The study shows, that including restraints based solely on {sup 1}H{sup N}-{sup 15}N residual dipolar couplings has pronounced impact on the backbone rmsd and Ramachandran plot but does not improve the hydrogen bond geometry. In the case of chymotrypsin inhibitor 2 the addition of {sup 13}CO-{sup 13}C{sup {alpha}} and {sup 15}N-{sup 13}CO one bond dipolar couplings as restraints in the structure calculations improved the hydrogen bond geometry to a quality comparable to that obtained in the 1.8 A resolution X-ray structure of this protein. A systematic restraint study was performed, in which four types of restraints, residual dipolar couplings, hydrogen bonds, TALOS angles and NOEs, were allowed in two states. This study revealed the importance of using several types of residual dipolar couplings to get good hydrogen bond geometry. The study also showed that using a small set of NOEs derived only from the amide protons, together with a full set of residual dipolar couplings resulted in structures of very high quality. When reducing the NOE set, it is mainly the side-chain to side-chain NOEs that are removed. Despite of this the effect on the side-chain packing is very small when a reduced NOE set is used, which implies that the over all fold of a protein structure is mainly determined by correct folding of the backbone.

  15. Determination of protein global folds using backbone residual dipolar coupling and long-range NOE restraints

    International Nuclear Information System (INIS)

    Giesen, Alexander W.; Homans, Steve W.; Brown, Jonathan Miles

    2003-01-01

    We report the determination of the global fold of human ubiquitin using protein backbone NMR residual dipolar coupling and long-range nuclear Overhauser effect (NOE) data as conformational restraints. Specifically, by use of a maximum of three backbone residual dipolar couplings per residue (N i -H N i , N i -C' i-1 , H N i - C' i-1 ) in two tensor frames and only backbone H N -H N NOEs, a global fold of ubiquitin can be derived with a backbone root-mean-square deviation of 1.4 A with respect to the crystal structure. This degree of accuracy is more than adequate for use in databases of structural motifs, and suggests a general approach for the determination of protein global folds using conformational restraints derived only from backbone atoms

  16. Partial alignment and measurement of residual dipolar couplings of proteins under high hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yinan; Wand, A. Joshua, E-mail: wand@mail.med.upenn.edu [University of Pennsylvania, Department of Biochemistry and Biophysics, Johnson Research Foundation (United States)

    2013-08-15

    High-pressure NMR spectroscopy has emerged as a complementary approach for investigating various structural and thermodynamic properties of macromolecules. Noticeably absent from the array of experimental restraints that have been employed to characterize protein structures at high hydrostatic pressure is the residual dipolar coupling, which requires the partial alignment of the macromolecule of interest. Here we examine five alignment media that are commonly used at ambient pressure for this purpose. We find that the spontaneous alignment of Pf1 phage, d(GpG) and a C12E5/n-hexnanol mixture in a magnetic field is preserved under high hydrostatic pressure. However, DMPC/DHPC bicelles and collagen gel are found to be unsuitable. Evidence is presented to demonstrate that pressure-induced structural changes can be identified using the residual dipolar coupling.

  17. Measurement of imino {sup 1}H-{sup 1}H residual dipolar couplings in RNA

    Energy Technology Data Exchange (ETDEWEB)

    Latham, Michael P. [University of Toronto, Department of Molecular Genetics (Canada); Pardi, Arthur [University of Colorado, Department of Chemistry and Biochemistry, 215 UCB (United States)], E-mail: arthur.pardi@colorado.edu

    2009-02-15

    Imino {sup 1}H-{sup 15}N residual dipolar couplings (RDCs) provide additional structural information that complements standard {sup 1}H-{sup 1}H NOEs leading to improvements in both the local and global structure of RNAs. Here, we report measurement of imino {sup 1}H-{sup 1}H RDCs for the Iron Responsive Element (IRE) RNA and native E. coli tRNA{sup Val} using a BEST-Jcomp-HMQC2 experiment. {sup 1}H-{sup 1}H RDCs are observed between the imino protons in G-U wobble base pairs and between imino protons on neighboring base pairs in both RNAs. These imino {sup 1}H-{sup 1}H RDCs complement standard {sup 1}H-{sup 15}N RDCs because the {sup 1}H-{sup 1}H vectors generally point along the helical axis, roughly perpendicular to {sup 1}H-{sup 15}N RDCs. The use of longitudinal relaxation enhancement increased the signal-to-noise of the spectra by {approx}3.5-fold over the standard experiment. The ability to measure imino {sup 1}H-{sup 1}H RDCs offers a new restraint, which can be used in NMR domain orientation and structural studies of RNAs.

  18. Direct Observation of Field and Temperature Induced Domain Replication in Dipolar Coupled Perpendicular Anisotropy Films

    Energy Technology Data Exchange (ETDEWEB)

    Hauet, T.; Gunther, C.M.; Pfau, B.; Eisebitt, S.; Fischer, P.; Rick, R. L.; Thiele, J.-U.; Hellwig, O.; Schabes, M.E.

    2007-07-01

    Dipolar interactions in a soft/Pd/hard [CoNi/Pd]{sub 30}/Pd/[Co/Pd]{sub 20} multilayer system, where a thick Pd layer between two ferromagnetic units prevents direct exchange coupling, are directly revealed by combining magnetometry and state-of-the-art layer resolving soft x-ray imaging techniques with sub-100-nm spatial resolution. The domains forming in the soft layer during external magnetic field reversal are found to match the domains previously trapped in the hard layer. The low Curie temperature of the soft layer allows varying its intrinsic parameters via temperature and thus studying the competition with dipolar fields due to the domains in the hard layer. Micromagnetic simulations elucidate the role of [CoNi/Pd] magnetization, exchange, and anisotropy in the duplication process. Finally, thermally driven domain replication in remanence during temperature cycling is demonstrated.

  19. Residual dipolar couplings in sup 3 sup 1 P MAS spectra of PPh sub 3 substituted cobalt complexes

    CERN Document Server

    Szalontai, G

    2002-01-01

    Residual dipolar couplings between sup 3 sup 1 P- sup 5 sup 9 Co spin pairs were studied in sup 3 sup 1 P MAS spectra of mono- and dinuclear cobalt-triphenylphosphine complexes. These spectra can provide important information such as the scalar coupling between the dipolar phosphorus and the quadrupolar cobalt nuclei normally not available from solution phase studies. In case of complementary (NQR or x-ray) data even the relative orientation of the interacting shielding, dipolar, scalar couplings, and electric field gradient tensors or internuclear distances can be determined. Examples are shown both for well resolved and practically unresolved cases, factors which possibly control the spectral resolution are discussed in detail. (author)

  20. A practical strategy for the accurate measurement of residual dipolar couplings in strongly aligned small molecules

    Science.gov (United States)

    Liu, Yizhou; Cohen, Ryan D.; Martin, Gary E.; Williamson, R. Thomas

    2018-06-01

    Accurate measurement of residual dipolar couplings (RDCs) requires an appropriate degree of alignment in order to optimize data quality. An overly weak alignment yields very small anisotropic data that are susceptible to measurement errors, whereas an overly strong alignment introduces extensive anisotropic effects that severely degrade spectral quality. The ideal alignment amplitude also depends on the specific pulse sequence used for the coupling measurement. In this work, we introduce a practical strategy for the accurate measurement of one-bond 13C-1H RDCs up to a range of ca. -300 to +300 Hz, corresponding to an alignment that is an order of magnitude stronger than typically employed for small molecule structural elucidation. This strong alignment was generated in the mesophase of the commercially available poly-γ-(benzyl-L-glutamate) polymer. The total coupling was measured by the simple and well-studied heteronuclear two-dimensional J-resolved experiment, which performs well in the presence of strong anisotropic effects. In order to unequivocally determine the sign of the total coupling and resolve ambiguities in assigning total couplings in the CH2 group, coupling measurements were conducted at an isotropic condition plus two anisotropic conditions of different alignment amplitudes. Most RDCs could be readily extracted from these measurements whereas more complicated spectral effects resulting from strong homonuclear coupling could be interpreted either theoretically or by simulation. Importantly, measurement of these very large RDCs actually offers significantly improved data quality and utility for the structure determination of small organic molecules.

  1. Quantitative conformational analysis of the core region of N-glycans using residual dipolar couplings, aqueous molecular dynamics, and steric alignment

    International Nuclear Information System (INIS)

    Almond, Andrew; Duus, Jens O.

    2001-01-01

    A method is described for quantitatively investigating the dynamic conformation of small oligosaccharides containing an α(1 → 6) linkage. It was applied to the oligosaccharide Man-α(1 → 3) {Man-α (1 → 6)}Man-α-O-Me, which is a core region frequently observed in N-linked glycans. The approach tests an aqueous molecular dynamics simulation, capable of predicting microscopic dynamics, against experimental residual dipolar couplings, by assuming that alignment is caused purely by steric hindrance. The experimental constraints were heteronuclear and homonuclear residual dipolar couplings, and in particular those within the α(1 → 6) linkage itself. Powerful spin-state-selective pulse sequences and editing schemes were used to obtain the most relevant couplings for testing the model. Molecular dynamics simulations in water over a period of 50 ns were not able to predict the correct rotamer population at the α(1 → 6) linkage to agree with the experimental data. However, this sampling problem could be corrected using a simple maximum likelihood optimisation, indicating that the simulation was modelling local dynamics correctly. The maximum likelihood prediction of the residual dipolar couplings was found to be an almost equal population of the gg and gt rotamer conformations at the α(1 → 6) linkage, and the tg conformation was predicted to be unstable and unpopulated in aqueous solution. In this case all twelve measured residual dipolar couplings could be satisfied. This conformer population could also be used to make predictions of scalar couplings with the use of a previously derived empirical equation, and is qualitatively in agreement with previous predictions based on NMR, X-ray crystallography and optical data

  2. Compiled data set of exact NOE distance limits, residual dipolar couplings and scalar couplings for the protein GB3

    Directory of Open Access Journals (Sweden)

    Beat Vögeli

    2015-12-01

    Full Text Available We compiled an NMR data set consisting of exact nuclear Overhauser enhancement (eNOE distance limits, residual dipolar couplings (RDCs and scalar (J couplings for GB3, which forms one of the largest and most diverse data set for structural characterization of a protein to date. All data have small experimental errors, which are carefully estimated. We use the data in the research article Vogeli et al., 2015, Complementarity and congruence between exact NOEs and traditional NMR probes for spatial decoding of protein dynamics, J. Struct. Biol., 191, 3, 306–317, doi:10.1016/j.jsb.2015.07.008 [1] for cross-validation in multiple-state structural ensemble calculation. We advocate this set to be an ideal test case for molecular dynamics simulations and structure calculations.

  3. A general assignment method for oriented sample (OS) solid-state NMR of proteins based on the correlation of resonances through heteronuclear dipolar couplings in samples aligned parallel and perpendicular to the magnetic field.

    Science.gov (United States)

    Lu, George J; Son, Woo Sung; Opella, Stanley J

    2011-04-01

    A general method for assigning oriented sample (OS) solid-state NMR spectra of proteins is demonstrated. In principle, this method requires only a single sample of a uniformly ¹⁵N-labeled membrane protein in magnetically aligned bilayers, and a previously assigned isotropic chemical shift spectrum obtained either from solution NMR on micelle or isotropic bicelle samples or from magic angle spinning (MAS) solid-state NMR on unoriented proteoliposomes. The sequential isotropic resonance assignments are transferred to the OS solid-state NMR spectra of aligned samples by correlating signals from the same residue observed in protein-containing bilayers aligned with their normals parallel and perpendicular to the magnetic field. The underlying principle is that the resonances from the same residue have heteronuclear dipolar couplings that differ by exactly a factor of two between parallel and perpendicular alignments. The method is demonstrated on the membrane-bound form of Pf1 coat protein in phospholipid bilayers, whose assignments have been previously made using an earlier generation of methods that relied on the preparation of many selectively labeled (by residue type) samples. The new method provides the correct resonance assignments using only a single uniformly ¹⁵N-labeled sample, two solid-state NMR spectra, and a previously assigned isotropic spectrum. Significantly, this approach is equally applicable to residues in alpha helices, beta sheets, loops, and any other elements of tertiary structure. Moreover, the strategy bridges between OS solid-state NMR of aligned samples and solution NMR or MAS solid-state NMR of unoriented samples. In combination with the development of complementary experimental methods, it provides a step towards unifying these apparently different NMR approaches. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Ordering and thermal excitations in dipolar coupled single domain magnet arrays (Presentation Recording)

    Science.gov (United States)

    Östman, Erik; Arnalds, Unnar; Kapaklis, Vassilios; Hjörvarsson, Björgvin

    2015-09-01

    For a small island of a magnetic material the magnetic state of the island is mainly determined by the exchange interaction and the shape anisotropy. Two or more islands placed in close proximity will interact through dipolar interactions. The state of a large system will thus be dictated by interactions at both these length scales. Enabling internal thermal fluctuations, e.g. by the choice of material, of the individual islands allows for the study of thermal ordering in extended nano-patterned magnetic arrays [1,2]. As a result nano-magnetic arrays represent an ideal playground for the study of physical model systems. Here we present three different studies all having used magneto-optical imaging techniques to observe, in real space, the order of the systems. The first study is done on a square lattice of circular islands. The remanent magnetic state of each island is a magnetic vortex structure and we can study the temperature dependence of the vortex nucleation and annihilation fields [3]. The second are long chains of dipolar coupled elongated islands where the magnetization direction in each island only can point in one of two possible directions. This creates a system which in many ways mimics the Ising model [4] and we can relate the correlation length to the temperature. The third one is a spin ice system where elongated islands are placed in a square lattice. Thermal excitations in such systems resemble magnetic monopoles [2] and we can investigate their properties as a function of temperature and lattice parameters. [1] V. Kapaklis et al., New J. Phys. 14, 035009 (2012) [2] V. Kapaklis et al., Nature Nanotech 9, 514(2014) [3] E. Östman et al.,New J. Phys. 16, 053002 (2014) [4] E. Östman et al.,Thermal ordering in mesoscopic Ising chains, In manuscript.

  5. Protein backbone motions viewed by intraresidue and sequential H{sup N}-H{sup {alpha}} residual dipolar couplings

    Energy Technology Data Exchange (ETDEWEB)

    Voegeli, Beat; Yao Lishan; Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: bax@nih.gov

    2008-05-15

    Triple resonance E.COSY-based techniques were used to measure intra-residue and sequential H{sup N}-H{sup {alpha}} residual dipolar couplings (RDCs) for the third IgG-binding domain of protein G (GB3), aligned in Pf1 medium. Measurements closely correlate with values predicted on the basis of an NMR structure, previously determined on the basis of a large number of one-bond backbone RDCs measured in five alignment media. However, in particular the sequential H{sup N}-H{sup {alpha}} RDCs are smaller than predicted for a static structure, suggesting a degree of motion for these internuclear vectors that exceeds that of the backbone amide N-H vectors. Of all experimentally determined GB3 structures available, the best correlation between experimental {sup 1}H-{sup 1}H couplings is observed for a GB3 ensemble, previously derived to generate a realistic picture of the conformational space sampled by GB3 (Clore and Schwieters, J Mol Biol 355:879-886, 2006). However, for both NMR and X-ray-derived structures the {sup 1}H-{sup 1}H couplings are found to be systematically smaller than expected on the basis of alignment tensors derived from {sup 15}N-{sup 1}H amide RDCs, assuming librationally corrected N-H bond lengths of 1.041 A.

  6. Independent alignment of RNA for dynamic studies using residual dipolar couplings

    Energy Technology Data Exchange (ETDEWEB)

    Bardaro, Michael F.; Varani, Gabriele, E-mail: varani@chem.washington.edu [University of Washington, Department of Chemistry (United States)

    2012-09-15

    Molecular motion and dynamics play an essential role in the biological function of many RNAs. An important source of information on biomolecular motion can be found in residual dipolar couplings which contain dynamics information over the entire ms-ps timescale. However, these methods are not fully applicable to RNA because nucleic acid molecules tend to align in a highly collinear manner in different alignment media. As a consequence, information on dynamics that can be obtained with this method is limited. In order to overcome this limitation, we have generated a chimeric RNA containing both the wild type TAR RNA, the target of our investigation of dynamics, as well as the binding site for U1A protein. When U1A protein was bound to the portion of the chimeric RNA containing its binding site, we obtained independent alignment of TAR by exploiting the physical chemical characteristics of this protein. This technique can allow the extraction of new information on RNA dynamics, which is particularly important for time scales not covered by relaxation methods where important RNA motions occur.

  7. Understanding the Origins of Dipolar Couplings and Correlated Motion in the Vibrational Spectrum of Water.

    Science.gov (United States)

    Heyden, Matthias; Sun, Jian; Forbert, Harald; Mathias, Gerald; Havenith, Martina; Marx, Dominik

    2012-08-16

    The combination of vibrational spectroscopy and molecular dynamics simulations provides a powerful tool to obtain insights into the molecular details of water structure and dynamics in the bulk and in aqueous solutions. Applying newly developed approaches to analyze correlations of charge currents, molecular dipole fluctuations, and vibrational motion in real and k-space, we compare results from nonpolarizable water models, widely used in biomolecular modeling, to ab initio molecular dynamics. For the first time, we unfold the infrared response of bulk water into contributions from correlated fluctuations in the three-dimensional, anisotropic environment of an average water molecule, from the OH-stretching region down to the THz regime. Our findings show that the absence of electronic polarizability in the force field model not only results in differences in dipolar couplings and infrared absorption but also induces artifacts into the correlated vibrational motion between hydrogen-bonded water molecules, specifically at the intramolecular bending frequency. Consequently, vibrational motion is partially ill-described with implications for the accuracy of non-self-consistent, a posteriori methods to add polarizability.

  8. Measurement of one-bond 15N-13C' dipolar couplings in medium sized proteins

    International Nuclear Information System (INIS)

    Chou, James J.; Delaglio, Frank; Bax, Ad

    2000-01-01

    A simple and accurate method is described for measurement of 1 J C'N splittings in isotopically enriched proteins. The method is of the quantitative J correlation type, and the 1 J C'N splitting is derived from the relative intensity in two 3D TROSY-HNCO spectra with 1 J C'N dephasing intervals of ∼1/(2 1 J C'N ) (reference intensity) and ∼1/ 1 J C'N (residual intensity). If the two spectra are recorded under identical conditions and with the same number of scans, the random error in the 1 J C'N value extracted in this manner is inversely related to the signal-to-noise (S/N) in the reference spectrum. A S/N of 30:1 in the reference spectrum yields random errors of less than 0.2 Hz in the extracted 1 J C'N value. Dipolar couplings obtained from the difference in 1 J C'N splitting in the isotropic and liquid crystalline phase for the C-terminal domain of calmodulin are in excellent agreement with its 1.68-A crystal structure, but agree considerably less with the 2.2-A structure

  9. J-Spectroscopy in the presence of residual dipolar couplings: determination of one-bond coupling constants and scalable resolution

    International Nuclear Information System (INIS)

    Furrer, Julien; John, Michael; Kessler, Horst; Luy, Burkhard

    2007-01-01

    The access to weak alignment media has fuelled the development of methods for efficiently and accurately measuring residual dipolar couplings (RDCs) in NMR-spectroscopy. Among the wealth of approaches for determining one-bond scalar and RDC constants only J-modulated and J-evolved techniques retain maximum resolution in the presence of differential relaxation. In this article, a number of J-evolved experiments are examined with respect to the achievable minimum linewidth in the J-dimension, using the peptide PA 4 and the 80-amino-acid-protein Saposin C as model systems. With the JE-N-BIRD d,X -HSQC experiment, the average full-width at half height could be reduced to approximately 5 Hz for the protein, which allows the additional resolution of otherwise unresolved peaks by the active (J+D)-coupling. Since RDCs generally can be scaled by the choice of alignment medium and alignment strength, the technique introduced here provides an effective resort in cases when chemical shift differences alone are insufficient for discriminating signals. In favorable cases even secondary structure elements can be distinguished

  10. Interlayer exchange coupling, dipolar coupling and magnetoresistance in Fe/MgO/Fe trilayers with a subnanometer MgO barrier

    Energy Technology Data Exchange (ETDEWEB)

    Kozioł-Rachwał, A. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Skowroński, W.; Frankowski, M. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Chęciński, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ziętek, S.; Rzeszut, P. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ślęzak, M.; Matlak, K.; Ślęzak, T. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Stobiecki, T. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Korecki, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland)

    2017-02-15

    Fe/MgO/Fe trilayers with a subnanometer MgO tunnel barrier were grown by molecular beam epitaxy. Longitudinal magnetooptic Kerr effect measurements confirmed the existence of the antiferromagnetic interlayer exchange coupling (IEC) between the Fe layers for 2 Åcoupling was enhanced for the trilayer grown on a homoepitaxial MgO buffer layer, and its IEC constant was estimated to be −3.3 erg/cm{sup 2} at a MgO thickness of 2.7 Å. After magnetic characterization, the sample was patterned into circular-shaped pillars with diameters ranging from 200 nm to 520 nm. We showed that the dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers, and we determined dependence of the dipolar coupling on the pillar diameter. Finally, magnetoresistance (MR) was measured as a function of MgO thickness (d{sub MgO}), and a non-zero MR was found for the MgO as thin as 3.4 Å. Extrapolation of the MR (d{sub MgO}) dependence to MR=0 allowed us to determine the length of the pinholes in our sample, which was estimated to be (3.2±0.5) Å. - Highlights: • Strong antiferromagnetic (AFM) interlayer exchange coupling (IEC) between Fe layers in Fe/MgO/Fe. • After nanofabrication the effective AFM IEC is enhanced due to the dipolar coupling. • The dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers. • Non-zero magnetoresistance values registered for the Fe/MgO/Fe trilayers with the MgO spacers as thin as 3.4 Å.

  11. Magnetic dipolar coupling and collective effects for binary information codification in cost-effective logic devices

    International Nuclear Information System (INIS)

    Chiolerio, Alessandro; Allia, Paolo; Graziano, Mariagrazia

    2012-01-01

    Physical limitations foreshadow the eventual end to traditional Complementary Metal Oxide Semiconductor (CMOS) scaling. Therefore, interest has turned to various materials and technologies aimed to succeed to traditional CMOS. Magnetic Quantum dot Cellular Automata (MQCA) are one of these technologies. Working MQCA arrays require very complex techniques and an excellent control on the geometry of the nanomagnets and on the quality of the magnetic thin film, thus limiting the possibility for MQCA of representing a definite solution to cost-effective, high density and low power consumption device demand. Counter-intuitively, moving towards bigger sizes and lighter technologies it is still possible to develop multi-state logic devices, as we demonstrated, whose main advantage is cost-effectiveness. Applications may be seen in low cost logic devices where integration and computational power are not the main issue, eventually using flexible substrates and taking advantage of the intrinsic mechanical toughness of systems where long range interactions do not need wirings. We realized cobalt micrometric MQCA arrays by means of Electron Beam Lithography, exploiting cost-effective processes such as lift-off and RF sputtering that usually are avoided due to their low control on array geometry and film roughness. Information relative to the magnetic configuration of MQCA elements including their eventual magnetic interactions was obtained from Magnetic Force Microscope (MFM) images, enhanced by means of a numerical procedure and presented in differential maps. We report the existence of bi-stable magnetic patterns, as detected by MFM while sampling the z-component of magnetic induction field, arising from dipolar inter-element magnetostatic coupling, able to store and propagate binary information. This is achieved despite the array quality and element magnetic state, which are low and multi-domain, respectively. We discuss in detail shape, inter-element spacing and dot profile

  12. Accurate measurement of heteronuclear dipolar couplings by phase-alternating R-symmetry (PARS) sequences in magic angle spinning NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Guangjin, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu; Lu, Xingyu, E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Vega, Alexander J., E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Polenova, Tatyana, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, Pennsylvania 15261 (United States)

    2014-09-14

    We report a Phase-Alternating R-Symmetry (PARS) dipolar recoupling scheme for accurate measurement of heteronuclear {sup 1}H-X (X = {sup 13}C, {sup 15}N, {sup 31}P, etc.) dipolar couplings in MAS NMR experiments. It is an improvement of conventional C- and R-symmetry type DIPSHIFT experiments where, in addition to the dipolar interaction, the {sup 1}H CSA interaction persists and thereby introduces considerable errors in the dipolar measurements. In PARS, phase-shifted RN symmetry pulse blocks applied on the {sup 1}H spins combined with π pulses applied on the X spins at the end of each RN block efficiently suppress the effect from {sup 1}H chemical shift anisotropy, while keeping the {sup 1}H-X dipolar couplings intact. Another advantage over conventional DIPSHIFT experiments, which require the signal to be detected in the form of a reduced-intensity Hahn echo, is that the series of π pulses refocuses the X chemical shift and avoids the necessity of echo formation. PARS permits determination of accurate dipolar couplings in a single experiment; it is suitable for a wide range of MAS conditions including both slow and fast MAS frequencies; and it assures dipolar truncation from the remote protons. The performance of PARS is tested on two model systems, [{sup 15}N]-N-acetyl-valine and [U-{sup 13}C,{sup 15}N]-N-formyl-Met-Leu-Phe tripeptide. The application of PARS for site-resolved measurement of accurate {sup 1}H-{sup 15}N dipolar couplings in the context of 3D experiments is presented on U-{sup 13}C,{sup 15}N-enriched dynein light chain protein LC8.

  13. Solution structure of tRNA{sup Val} from refinement of homology model against residual dipolar coupling and SAXS data

    Energy Technology Data Exchange (ETDEWEB)

    Grishaev, Alexander, E-mail: AlexanderG@intra.niddk.nih.gov; Ying, Jinfa [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Canny, Marella D.; Pardi, Arthur [University of Colorado, Boulder, Department of Chemistry and Biochemistry, 215 UCB (United States)], E-mail: Arthur.Pardi@Colorado.edu; Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: bax@nih.gov

    2008-10-15

    A procedure is presented for refinement of a homology model of E. coli tRNA{sup Val}, originally based on the X-ray structure of yeast tRNA{sup Phe}, using experimental residual dipolar coupling (RDC) and small angle X-ray scattering (SAXS) data. A spherical sampling algorithm is described for refinement against SAXS data that does not require a globbic approximation, which is particularly important for nucleic acids where such approximations are less appropriate. Substantially higher speed of the algorithm also makes its application favorable for proteins. In addition to the SAXS data, the structure refinement employed a sparse set of NMR data consisting of 24 imino N-H{sup N} RDCs measured with Pf1 phage alignment, and 20 imino N-H{sup N} RDCs obtained from magnetic field dependent alignment of tRNA{sup Val}. The refinement strategy aims to largely retain the local geometry of the 58% identical tRNA{sup Phe} by ensuring that the atomic coordinates for short, overlapping segments of the ribose-phosphate backbone and the conserved base pairs remain close to those of the starting model. Local coordinate restraints are enforced using the non-crystallographic symmetry (NCS) term in the XPLOR-NIH or CNS software package, while still permitting modest movements of adjacent segments. The RDCs mainly drive the relative orientation of the helical arms, whereas the SAXS restraints ensure an overall molecular shape compatible with experimental scattering data. The resulting structure exhibits good cross-validation statistics (jack-knifed Q{sub free} = 14% for the Pf1 RDCs, compared to 25% for the starting model) and exhibits a larger angle between the two helical arms than observed in the X-ray structure of tRNA{sup Phe}, in agreement with previous NMR-based tRNA{sup Val} models.

  14. Two dimensional dipolar coupling in monolayers of silver and gold nanoparticles on a dielectric substrate.

    Science.gov (United States)

    Liu, Yu; Begin-Colin, Sylvie; Pichon, Benoît P; Leuvrey, Cedric; Ihiawakrim, Dris; Rastei, Mircea; Schmerber, Guy; Vomir, Mircea; Bigot, Jean Yves

    2014-10-21

    The dimensionality of assembled nanoparticles plays an important role in their optical and magnetic properties, via dipolar effects and the interaction with their environment. In this work we develop a methodology for distinguishing between two (2D) and three (3D) dimensional collective interactions on the surface plasmon resonance of assembled metal nanoparticles. Towards that goal, we elaborate different sets of Au and Ag nanoparticles as suspensions, random 3D arrangements and well organized 2D arrays. Then we model their scattering cross-section using effective field methods in dimension n, including interparticle as well as particle-substrate dipolar interactions. For this modelling, two effective field medium approaches are employed, taking into account the filling factors of the assemblies. Our results are important for realizing photonic amplifier devices.

  15. De novo determination of internuclear vector orientations from residual dipolar couplings measured in three independent alignment media

    International Nuclear Information System (INIS)

    Ruan Ke; Briggman, Kathryn B.; Tolman, Joel R.

    2008-01-01

    The straightforward interpretation of solution state residual dipolar couplings (RDCs) in terms of internuclear vector orientations generally requires prior knowledge of the alignment tensor, which in turn is normally estimated using a structural model. We have developed a protocol which allows the requirement for prior structural knowledge to be dispensed with as long as RDC measurements can be made in three independent alignment media. This approach, called Rigid Structure from Dipolar Couplings (RSDC), allows vector orientations and alignment tensors to be determined de novo from just three independent sets of RDCs. It is shown that complications arising from the existence of multiple solutions can be overcome by careful consideration of alignment tensor magnitudes in addition to the agreement between measured and calculated RDCs. Extensive simulations as well applications to the proteins ubiquitin and Staphylococcal protein GB1 demonstrate that this method can provide robust determinations of alignment tensors and amide N-H bond orientations often with better than 10 o accuracy, even in the presence of modest levels of internal dynamics

  16. iDC: A comprehensive toolkit for the analysis of residual dipolar couplings for macromolecular structure determination

    International Nuclear Information System (INIS)

    Wei Yufeng; Werner, Milton H.

    2006-01-01

    Measurement of residual dipolar couplings (RDCs) has become an important method for the determination and validation of protein or nucleic acid structures by NMRf spectroscopy. A number of toolkits have been devised for the handling of RDC data which run in the Linux/Unix operating environment and require specifically formatted input files. The outputs from these programs, while informative, require format modification prior to the incorporation of this data into commonly used personal computer programs for manuscript preparation. To bridge the gap between analysis and publication, an easy-to-use, comprehensive toolkit for RDC analysis has been created, iDC. iDC is written for the WaveMetrics Igor Pro mathematics program, a widely used graphing and data analysis software program that runs on both Windows PC and Mac OS X computers. Experimental RDC values can be loaded into iDC using simple data formats accessible to Igor's tabular data function. The program can perform most useful RDC analyses, including alignment tensor estimation from a histogram of RDC occurrence versus values and order tensor analysis by singular value decomposition (SVD). SVD analysis can be performed on an entire structure family at once, a feature missing in other applications of this kind. iDC can also import from and export to several different commonly used programs for the analysis of RDC data (DC, PALES, REDCAT) and can prepare formatted files for RDC-based refinement of macromolecular structures using XPLOR-NIH, CNS and ARIA. The graphical user interface provides an easy-to-use I/O for data, structures and formatted outputs

  17. Broadband cross-polarization-based heteronuclear dipolar recoupling for structural and dynamic NMR studies of rigid and soft solids

    International Nuclear Information System (INIS)

    Kharkov, B. B.; Chizhik, V. I.; Dvinskikh, S. V.

    2016-01-01

    Dipolar recoupling is an essential part of current solid-state NMR methodology for probing atomic-resolution structure and dynamics in solids and soft matter. Recently described magic-echo amplitude- and phase-modulated cross-polarization heteronuclear recoupling strategy aims at efficient and robust recoupling in the entire range of coupling constants both in rigid and highly dynamic molecules. In the present study, the properties of this recoupling technique are investigated by theoretical analysis, spin-dynamics simulation, and experimentally. The resonance conditions and the efficiency of suppressing the rf field errors are examined and compared to those for other recoupling sequences based on similar principles. The experimental data obtained in a variety of rigid and soft solids illustrate the scope of the method and corroborate the results of analytical and numerical calculations. The technique benefits from the dipolar resolution over a wider range of coupling constants compared to that in other state-of-the-art methods and thus is advantageous in studies of complex solids with a broad range of dynamic processes and molecular mobility degrees

  18. Low-loss metamaterial electromagnetically induced transparency based on electric toroidal dipolar response

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hai-ming; Liu, Shao-bin, E-mail: lsb@nuaa.edu.cn; Liu, Si-yuan; Ding, Guo-wen; Yang, Hua; Yu, Zhi-yang; Zhang, Hai-feng [Key Laboratory of Radar Imaging and Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 (China); Wang, Shen-yun [Research Center of Applied Electromagnetic, Nanjing University of Information Science and Technology, Nanjing, 210044 (China)

    2015-02-23

    In this paper, a low-loss and high transmission analogy of electromagnetically induced transparency based on electric toroidal dipolar response is numerically and experimentally demonstrated. It is obtained by the excitation of the low-loss electric toroidal dipolar response, which confines the magnetic field inside a dielectric substrate with toroidal geometry. The metamaterial electromagnetically induced transparency (EIT) structure is composed of the cut wire and asymmetric split-ring resonators. The transmission level is as high as 0.88, and the radiation loss is greatly suppressed, which can be proved by the surface currents distributions, the magnetic field distributions, and the imaginary parts of the effective permeability and permittivity. It offers an effective way to produce low-loss and high transmission metamaterial EIT.

  19. Structure-independent cross-validation between residual dipolar couplings originating from internal and external orienting media

    International Nuclear Information System (INIS)

    Barbieri, Renato; Bertini, Ivano; Lee, Yong-Min; Luchinat, Claudio; Velders, Aldrik H.

    2002-01-01

    Lanthanide-substituted calcium binding proteins are known to partially orient in high magnetic fields. Orientation provides residual dipolar couplings (rdc's). Two of these systems, Tm 3+ - and Dy 3+ -substituted calbindin D 9k , dissolved in an external orienting medium (nonionic liquid crystalline phase) provide rdc values which are the sum of those induced by the lanthanides and by the liquid crystalline phase on the native calcium binding protein. This structure-independent check shows the innocence of the orienting medium with respect to the structure of the protein in solution. Furthermore, the simultaneous use of lanthanide substitution and external orienting media provides a further effective tool to control and tune the orientation tensor

  20. An encodable lanthanide binding tag with reduced size and flexibility for measuring residual dipolar couplings and pseudocontact shifts in large proteins

    Energy Technology Data Exchange (ETDEWEB)

    Barb, Adam W., E-mail: abarb@iastate.edu; Subedi, Ganesh P. [Iowa State University, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology (United States)

    2016-01-15

    Metal ions serve important roles in structural biology applications from long-range perturbations seen in magnetic resonance experiments to electron-dense signatures in X-ray crystallography data; however, the metal ion must be secured in a molecular framework to achieve the maximum benefit. Polypeptide-based lanthanide-binding tags (LBTs) represent one option that can be directly encoded within a recombinant protein expression construct. However, LBTs often exhibit significant mobility relative to the target molecule. Here we report the characterization of improved LBTs sequences for insertion into a protein loop. These LBTs were inserted to connect two parallel alpha helices of an immunoglobulin G (IgG)-binding Z domain platform. Variants A and B bound Tb{sup 3+} with high affinity (0.70 and 0.13 μM, respectively) and displayed restricted LBT motion. Compared to the parent construct, the metal-bound A experienced a 2.5-fold reduction in tag motion as measured by magnetic field-induced residual dipolar couplings and was further studied in a 72.2 kDa complex with the human IgG1 fragment crystallizable (IgG1 Fc) glycoprotein. The appearance of both pseudo-contact shifts (−0.221 to 0.081 ppm) and residual dipolar couplings (−7.6 to 14.3 Hz) of IgG1 Fc resonances in the IgG1 Fc:(variant A:Tb{sup 3+}){sub 2} complex indicated structural restriction of the LBT with respect to the Fc. These studies highlight the applicability of improved LBT sequences with reduced mobility to probe the structure of macromolecular systems.

  1. An encodable lanthanide binding tag with reduced size and flexibility for measuring residual dipolar couplings and pseudocontact shifts in large proteins

    International Nuclear Information System (INIS)

    Barb, Adam W.; Subedi, Ganesh P.

    2016-01-01

    Metal ions serve important roles in structural biology applications from long-range perturbations seen in magnetic resonance experiments to electron-dense signatures in X-ray crystallography data; however, the metal ion must be secured in a molecular framework to achieve the maximum benefit. Polypeptide-based lanthanide-binding tags (LBTs) represent one option that can be directly encoded within a recombinant protein expression construct. However, LBTs often exhibit significant mobility relative to the target molecule. Here we report the characterization of improved LBTs sequences for insertion into a protein loop. These LBTs were inserted to connect two parallel alpha helices of an immunoglobulin G (IgG)-binding Z domain platform. Variants A and B bound Tb 3+ with high affinity (0.70 and 0.13 μM, respectively) and displayed restricted LBT motion. Compared to the parent construct, the metal-bound A experienced a 2.5-fold reduction in tag motion as measured by magnetic field-induced residual dipolar couplings and was further studied in a 72.2 kDa complex with the human IgG1 fragment crystallizable (IgG1 Fc) glycoprotein. The appearance of both pseudo-contact shifts (−0.221 to 0.081 ppm) and residual dipolar couplings (−7.6 to 14.3 Hz) of IgG1 Fc resonances in the IgG1 Fc:(variant A:Tb 3+ ) 2 complex indicated structural restriction of the LBT with respect to the Fc. These studies highlight the applicability of improved LBT sequences with reduced mobility to probe the structure of macromolecular systems

  2. Longitudinal expansion of field line dipolarization

    Science.gov (United States)

    Saka, O.; Hayashi, K.

    2017-11-01

    We examine the substorm expansions that started at 1155 UT 10 August 1994 in the midnight sector focusing on the longitudinal (eastward) expansion of field line dipolarization in the auroral zone. Eastward expansion of the dipolarization region was observed in all of the H, D, and Z components. The dipolarization that started at 1155 UT (0027 MLT) from 260° of geomagnetic longitude (CMO) expanded to 351°(PBQ) in about 48 min. The expansion velocity was 0.03-0.04°/s, or 1.9 km/s at 62°N of geomagnetic latitude. The dipolarization region expanding to the east was accompanied by a bipolar event at the leading edge of the expansion in latitudes equatorward of the westward electrojet (WEJ). In the midnight sector at the onset meridian, the Magnetospheric Plasma Analyzer (MAP) on board geosynchronous satellite L9 measured electrons and ions between 10 eV and 40 keV. We conclude from the satellite observations that this dipolarization was characterized by the evolution of temperature anisotropies, an increase of the electron and ion temperatures, and a rapid change in the symmetry axis of the temperature tensor. The field line dipolarization and its longitudinal expansion were interpreted in terms of the slow MHD mode triggered by the current disruption. We propose a new magnetosphere-ionosphere coupling (MI-coupling) mechanism based on the scenario that transmitted westward electric fields from the magnetosphere in association with expanding dipolarization produced electrostatic potential (negative) in the ionosphere through differences in the mobility of collisional ions and collisionless electrons. The field-aligned currents that emerged from the negative potential region are arranged in a concentric pattern around the negative potential region, upward toward the center and downward on the peripheral.

  3. Relaxation dynamics of a driven two-level system coupled to a Bose-Einstein condensate: application to quantum dot-dipolar exciton gas hybrid systems.

    Science.gov (United States)

    Kovalev, Vadim M; Tse, Wang-Kong

    2017-11-22

    We develop a microscopic theory for the relaxation dynamics of an optically pumped two-level system (TLS) coupled to a bath of weakly interacting Bose gas. Using Keldysh formalism and diagrammatic perturbation theory, expressions for the relaxation times of the TLS Rabi oscillations are derived when the boson bath is in the normal state and the Bose-Einstein condensate (BEC) state. We apply our general theory to consider an irradiated quantum dot coupled with a boson bath consisting of a two-dimensional dipolar exciton gas. When the bath is in the BEC regime, relaxation of the Rabi oscillations is due to both condensate and non-condensate fractions of the bath bosons for weak TLS-light coupling and pre dominantly due to the non-condensate fraction for strong TLS-light coupling. Our theory also shows that a phase transition of the bath from the normal to the BEC state strongly influences the relaxation rate of the TLS Rabi oscillations. The TLS relaxation rate is approximately independent of the pump field frequency and monotonically dependent on the field strength when the bath is in the low-temperature regime of the normal phase. Phase transition of the dipolar exciton gas leads to a non-monotonic dependence of the TLS relaxation rate on both the pump field frequency and field strength, providing a characteristic signature for the detection of BEC phase transition of the coupled dipolar exciton gas.

  4. Controlling residual dipolar couplings in high-resolution NMR of proteins by strain induced alignment in a gel

    International Nuclear Information System (INIS)

    Ishii, Yoshitaka; Markus, Michelle A.; Tycko, Robert

    2001-01-01

    Water-soluble biological macromolecules can be weakly aligned by dissolution in a strained, hydrated gel such as cross-linked polyacrylamide, an effect termed 'strain-induced alignment in a gel' (SAG). SAG induces nonzero nuclear magnetic dipole-dipole couplings that can be measured in high-resolution NMR spectra and used as structural constraints. The dependence of experimental 15 N- 1 H dipolar couplings extracted from two-dimensional heteronuclear single quantum coherence (HSQC) spectra on several properties of compressed polyacrylamide, including the extent of compression, the polyacrylamide concentration, and the cross-link density, is reported for the B1 immunoglobulin binding domain of streptococcal protein G (protein G/B1, 57 residues). It is shown that the magnitude of macromolecular alignment can be widely varied by adjusting these properties, although the orientation and asymmetry of the alignment tensor are not affected significantly. The dependence of the 15 N relaxation times T 1 and T 2 of protein G/B1 on polyacrylamide concentration are also reported. In addition, the results of 15 N relaxation and HSQC experiments on the RNA binding domain of prokaryotic protein S4 from Bacillus stearothermophilus (S4 Δ41, residues 43-200) in a compressed polyacrylamide gel are presented. These results demonstrate the applicability of SAG to proteins of higher molecular weight and greater complexity. A modified in-phase/anti-phase (IPAP) HSQC technique is described that suppresses natural-abundance 15 N background signals from amide groups in polyacrylamide, resulting in cleaner HSQC spectra in SAG experiments. The mechanism of protein alignment in strained polyacrylamide gels is contrasted with that in liquid crystalline media

  5. Measurement of {sup 1}H-{sup 15}N and {sup 1}H-{sup 13}C residual dipolar couplings in nucleic acids from TROSY intensities

    Energy Technology Data Exchange (ETDEWEB)

    Ying Jinfa [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Wang Jinbu [National Cancer Institute, National Institutes of Health, Structural Biophysics Laboratory (United States); Grishaev, Alex [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Yu Ping; Wang Yunxing [National Cancer Institute, National Institutes of Health, Structural Biophysics Laboratory (United States); Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2011-09-15

    Analogous to the recently introduced ARTSY method for measurement of one-bond {sup 1}H-{sup 15}N residual dipolar couplings (RDCs) in large perdeuterated proteins, we introduce methods for measurement of base {sup 13}C-{sup 1}H and {sup 15}N-{sup 1}H RDCs in protonated nucleic acids. Measurements are based on quantitative analysis of intensities in {sup 1}H-{sup 15}N and {sup 13}C-{sup 1}H TROSY-HSQC spectra, and are illustrated for a 71-nucleotide adenine riboswitch. Results compare favorably with those of conventional frequency-based measurements in terms of completeness and convenience of use. The ARTSY method derives the size of the coupling from the ratio of intensities observed in two TROSY-HSQC spectra recorded with different dephasing delays, thereby minimizing potential resonance overlap problems. Precision of the RDC measurements is limited by the signal-to-noise ratio, S/N, achievable in the 2D TROSY-HSQC reference spectrum, and is approximately given by 30/(S/N) Hz for {sup 15}N-{sup 1}H and 65/(S/N) Hz for {sup 13}C-{sup 1}H. The signal-to-noise ratio of both {sup 1}H-{sup 15}N and {sup 1}H-{sup 13}C spectra greatly benefits when water magnetization during the experiments is not perturbed, such that rapid magnetization transfer from bulk water to the nucleic acid, mediated by rapid amino and hydroxyl hydrogen exchange coupled with {sup 1}H-{sup 1}H NOE transfer, allows for fast repetition of the experiment. RDCs in the mutated helix 1 of the riboswitch are compatible with nucleotide-specifically modeled, idealized A-form geometry and a static orientation relative to the helix 2/3 pair, which differs by ca 6 Degree-Sign relative to the X-ray structure of the native riboswitch.

  6. Visualization of magnetic dipolar interaction based on scanning transmission X-ray microscopy

    International Nuclear Information System (INIS)

    Ohtori, Hiroyuki; Iwano, Kaoru; Takeichi, Yasuo; Ono, Kanta; Mitsumata, Chiharu; Yano, Masao; Kato, Akira; Miyamoto, Noritaka; Shoji, Tetsuya; Manabe, Akira

    2014-01-01

    Using scanning transmission X-ray microscopy (STXM), in this report we visualized the magnetic dipolar interactions in nanocrystalline Nd-Fe-B magnets and imaged their magnetization distributions at various applied fields. We calculated the magnetic dipolar interaction by analyzing the interaction between the magnetization at each point and those at the other points on the STXM image.

  7. Accurate characterization of weak macromolecular interactions by titration of NMR residual dipolar couplings: application to the CD2AP SH3-C:ubiquitin complex.

    Science.gov (United States)

    Ortega-Roldan, Jose Luis; Jensen, Malene Ringkjøbing; Brutscher, Bernhard; Azuaga, Ana I; Blackledge, Martin; van Nuland, Nico A J

    2009-05-01

    The description of the interactome represents one of key challenges remaining for structural biology. Physiologically important weak interactions, with dissociation constants above 100 muM, are remarkably common, but remain beyond the reach of most of structural biology. NMR spectroscopy, and in particular, residual dipolar couplings (RDCs) provide crucial conformational constraints on intermolecular orientation in molecular complexes, but the combination of free and bound contributions to the measured RDC seriously complicates their exploitation for weakly interacting partners. We develop a robust approach for the determination of weak complexes based on: (i) differential isotopic labeling of the partner proteins facilitating RDC measurement in both partners; (ii) measurement of RDC changes upon titration into different equilibrium mixtures of partially aligned free and complex forms of the proteins; (iii) novel analytical approaches to determine the effective alignment in all equilibrium mixtures; and (iv) extraction of precise RDCs for bound forms of both partner proteins. The approach is demonstrated for the determination of the three-dimensional structure of the weakly interacting CD2AP SH3-C:Ubiquitin complex (K(d) = 132 +/- 13 muM) and is shown, using cross-validation, to be highly precise. We expect this methodology to extend the remarkable and unique ability of NMR to study weak protein-protein complexes.

  8. Threshold-Voltage Shifts in Organic Transistors Due to Self-Assembled Monolayers at the Dielectric: Evidence for Electronic Coupling and Dipolar Effects.

    Science.gov (United States)

    Aghamohammadi, Mahdieh; Rödel, Reinhold; Zschieschang, Ute; Ocal, Carmen; Boschker, Hans; Weitz, R Thomas; Barrena, Esther; Klauk, Hagen

    2015-10-21

    The mechanisms behind the threshold-voltage shift in organic transistors due to functionalizing of the gate dielectric with self-assembled monolayers (SAMs) are still under debate. We address the mechanisms by which SAMs determine the threshold voltage, by analyzing whether the threshold voltage depends on the gate-dielectric capacitance. We have investigated transistors based on five oxide thicknesses and two SAMs with rather diverse chemical properties, using the benchmark organic semiconductor dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene. Unlike several previous studies, we have found that the dependence of the threshold voltage on the gate-dielectric capacitance is completely different for the two SAMs. In transistors with an alkyl SAM, the threshold voltage does not depend on the gate-dielectric capacitance and is determined mainly by the dipolar character of the SAM, whereas in transistors with a fluoroalkyl SAM the threshold voltages exhibit a linear dependence on the inverse of the gate-dielectric capacitance. Kelvin probe force microscopy measurements indicate this behavior is attributed to an electronic coupling between the fluoroalkyl SAM and the organic semiconductor.

  9. Experimental implementation of a quantum random-walk search algorithm using strongly dipolar coupled spins

    International Nuclear Information System (INIS)

    Lu Dawei; Peng Xinhua; Du Jiangfeng; Zhu Jing; Zou Ping; Yu Yihua; Zhang Shanmin; Chen Qun

    2010-01-01

    An important quantum search algorithm based on the quantum random walk performs an oracle search on a database of N items with O(√(phN)) calls, yielding a speedup similar to the Grover quantum search algorithm. The algorithm was implemented on a quantum information processor of three-qubit liquid-crystal nuclear magnetic resonance (NMR) in the case of finding 1 out of 4, and the diagonal elements' tomography of all the final density matrices was completed with comprehensible one-dimensional NMR spectra. The experimental results agree well with the theoretical predictions.

  10. Rapid measurement of residual dipolar couplings for fast fold elucidation of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Rasia, Rodolfo M. [Jean-Pierre Ebel CNRS/CEA/UJF, Institut de Biologie Structurale (France); Lescop, Ewen [CNRS, Institut de Chimie des Substances Naturelles (France); Palatnik, Javier F. [Universidad Nacional de Rosario, Instituto de Biologia Molecular y Celular de Rosario, Facultad de Ciencias Bioquimicas y Farmaceuticas (Argentina); Boisbouvier, Jerome, E-mail: jerome.boisbouvier@ibs.fr; Brutscher, Bernhard, E-mail: Bernhard.brutscher@ibs.fr [Jean-Pierre Ebel CNRS/CEA/UJF, Institut de Biologie Structurale (France)

    2011-11-15

    It has been demonstrated that protein folds can be determined using appropriate computational protocols with NMR chemical shifts as the sole source of experimental restraints. While such approaches are very promising they still suffer from low convergence resulting in long computation times to achieve accurate results. Here we present a suite of time- and sensitivity optimized NMR experiments for rapid measurement of up to six RDCs per residue. Including such an RDC data set, measured in less than 24 h on a single aligned protein sample, greatly improves convergence of the Rosetta-NMR protocol, allowing for overnight fold calculation of small proteins. We demonstrate the performance of our fast fold calculation approach for ubiquitin as a test case, and for two RNA-binding domains of the plant protein HYL1. Structure calculations based on simulated RDC data highlight the importance of an accurate and precise set of several complementary RDCs as additional input restraints for high-quality de novo structure determination.

  11. Solid-state NMR detection of 14N-13C dipolar couplings between amino acid side groups provides constraints on amyloid fibril architecture.

    Science.gov (United States)

    Middleton, David A

    2011-02-01

    Solid-state nuclear magnetic resonance (SSNMR) is a powerful technique for the structural analysis of amyloid fibrils. With suitable isotope labelling patterns, SSNMR can provide constraints on the secondary structure, alignment and registration of β-strands within amyloid fibrils and identify the tertiary and quaternary contacts defining the packing of the β-sheet layers. Detection of (14)N-(13)C dipolar couplings may provide potentially useful additional structural constraints on β-sheet packing within amyloid fibrils but has not until now been exploited for this purpose. Here a frequency-selective, transfer of population in double resonance SSNMR experiment is used to detect a weak (14)N-(13)C dipolar coupling in amyloid-like fibrils of the peptide H(2)N-SNNFGAILSS-COOH, which was uniformly (13)C and (15)N labelled across the four C-terminal amino acids. The (14)N-(13)C interatomic distance between leucine and asparagine side groups is constrained between 2.4 and 3.8 Å, which allows current structural models of the β-spine arrangement within the fibrils to be refined. This procedure could be useful for the general structural analysis of other proteins in condensed phases and environments, such as biological membranes. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Inclusion Compound Based Approach to Arrays of Artificial Dipolar Molecular Rotors. A Surface Inclusion

    Czech Academy of Sciences Publication Activity Database

    Kobr, L.; Zhao, K.; Shen, K.; Comotti, A.; Bracco, S.; Shoemaker, R. K.; Sozzani, P.; Clark, N.A.; Price, J. C.; Rogers, C. T.; Michl, Josef

    2012-01-01

    Roč. 134, č. 24 (2012), s. 10122-10131 ISSN 0002-7863 EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional research plan: CEZ:AV0Z40550506 Keywords : controlled rotary motion * solid-state dynamics * aromatic nanochannels * NMR-spectroscopy * single-molecule Subject RIV: CC - Organic Chemistry Impact factor: 10.677, year: 2012

  13. Inclusion Compound Based Approach to Arrays of Artificial Dipolar Molecular Rotors: Bulk Inclusions

    Czech Academy of Sciences Publication Activity Database

    Kobr, L.; Zhao, K.; Shen, Y.; Polívková, Kateřina; Shoemaker, R. K.; Clark, N.A.; Price, J. C.; Rogers, C. T.; Michl, Josef

    2013-01-01

    Roč. 78, č. 5 (2013), s. 1768-1777 ISSN 0022-3263 EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional support: RVO:61388963 Keywords : solid-state dynamics * phosphonitrilic compounds * aromatic nanochannels * triethylamine Subject RIV: CC - Organic Chemistry Impact factor: 4.638, year: 2013

  14. Curie temperature and magnetic phase transition of nanostructured ultrathin Fe/GaAs (001). Size dependence and relevance of dipolar coupling

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Roland

    2009-07-01

    In the present work the impact of lateral patterning of ultrathin ferromagnetic films down to the nanometer range on the magnetic phase transition has been investigated. In this respect on the one hand a size effect on the Curie temperature and, referring to that, the relevance of dipolar coupling were a matter of particular interest. On the other hand the characteristics of the critical behavior itself, becoming apparent by the accurate evaluation of the curvature shape of the magnetization as a function of temperature at T{sub c}, were analyzed with regard to potential and expected size effects. The investigation of similar nanostructures with respect to an effect on Curie temperature respectively phase transition may draw up a correlation. Therefore more than hundred samples were fabricated for this work extensively by means of MBE (Molecular Beam Epitaxy) and ESL (Electron Beam Epitaxy) methods, measured by MOKE (Magneto-Optical Kerr Effect) technique and systematically evaluated. (orig.)

  15. Facile measurement of {sup 1}H-{sup 15}N residual dipolar couplings in larger perdeuterated proteins

    Energy Technology Data Exchange (ETDEWEB)

    Fitzkee, Nicholas C.; Bax, Ad, E-mail: bax@nih.go [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2010-10-15

    We present a simple method, ARTSY, for extracting {sup 1}J{sub NH} couplings and {sup 1}H-{sup 15}N RDCs from an interleaved set of two-dimensional {sup 1}H-{sup 15}N TROSY-HSQC spectra, based on the principle of quantitative J correlation. The primary advantage of the ARTSY method over other methods is the ability to measure couplings without scaling peak positions or altering the narrow line widths characteristic of TROSY spectra. Accuracy of the method is demonstrated for the model system GB3. Application to the catalytic core domain of HIV integrase, a 36 kDa homodimer with unfavorable spectral characteristics, demonstrates its practical utility. Precision of the RDC measurement is limited by the signal-to-noise ratio, S/N, achievable in the 2D TROSY-HSQC spectrum, and is approximately given by 30/(S/N) Hz.

  16. Computing distance distributions from dipolar evolution data with overtones: RIDME spectroscopy with Gd(iii)-based spin labels.

    Science.gov (United States)

    Keller, Katharina; Mertens, Valerie; Qi, Mian; Nalepa, Anna I; Godt, Adelheid; Savitsky, Anton; Jeschke, Gunnar; Yulikov, Maxim

    2017-07-21

    Extraction of distance distributions between high-spin paramagnetic centers from relaxation induced dipolar modulation enhancement (RIDME) data is affected by the presence of overtones of dipolar frequencies. As previously proposed, we account for these overtones by using a modified kernel function in Tikhonov regularization analysis. This paper analyzes the performance of such an approach on a series of model compounds with the Gd(iii)-PyMTA complex serving as paramagnetic high-spin label. We describe the calibration of the overtone coefficients for the RIDME kernel, demonstrate the accuracy of distance distributions obtained with this approach, and show that for our series of Gd-rulers RIDME technique provides more accurate distance distributions than Gd(iii)-Gd(iii) double electron-electron resonance (DEER). The analysis of RIDME data including harmonic overtones can be performed using the MATLAB-based program OvertoneAnalysis, which is available as open-source software from the web page of ETH Zurich. This approach opens a perspective for the routine use of the RIDME technique with high-spin labels in structural biology and structural studies of other soft matter.

  17. Structure of calmodulin complexed with an olfactory CNG channel fragment and role of the central linker: Residual dipolar couplings to evaluate calmodulin binding modes outside the kinase family

    International Nuclear Information System (INIS)

    Contessa, Gian Marco; Orsale, Maria; Melino, Sonia; Torre, Vincent; Paci, Maurizio; Desideri, Alessandro; Cicero, Daniel O.

    2005-01-01

    The NMR high-resolution structure of calmodulin complexed with a fragment of the olfactory cyclic-nucleotide gated channel is described. This structure shows features that are unique for this complex, including an active role of the linker connecting the N- and C-lobes of calmodulin upon binding of the peptide. Such linker is not only involved in the formation of an hydrophobic pocket to accommodate a bulky peptide residue, but it also provides a positively charged region complementary to a negative charge of the target. This complex of calmodulin with a target not belonging to the kinase family was used to test the residual dipolar coupling (RDC) approach for the determination of calmodulin binding modes to peptides. Although the complex here characterized belongs to the (1--14) family, high Q values were obtained with all the 1:1 complexes for which crystalline structures are available. Reduction of the RDC data set used for the correlation analysis to structured regions of the complex allowed a clear identification of the binding mode. Excluded regions comprise calcium binding loops and loops connecting the EF-hand motifs

  18. Concerted motions in HIV-1 TAR RNA may allow access to bound state conformations: RNA dynamics from NMR residual dipolar couplings.

    Science.gov (United States)

    Al-Hashimi, Hashim M; Gosser, Yuying; Gorin, Andrey; Hu, Weidong; Majumdar, Ananya; Patel, Dinshaw J

    2002-01-11

    Ground-state dynamics in RNA is a critical precursor for structural adaptation observed ubiquitously in protein-RNA recognition. A tertiary conformational analysis of the stem-loop structural element in the transactivation response element (TAR) from human immunodeficiency virus type 1 (HIV-I) RNA is presented using recently introduced NMR methods that rely on the measurement of residual dipolar couplings (RDC) in partially oriented systems. Order matrix analysis of RDC data provides evidence for inter-helical motions that are of amplitude 46(+/-4) degrees, of random directional character, and that are executed about an average conformation with an inter-helical angle between 44 degrees and 54 degrees. The generated ensemble of TAR conformations have different organizations of functional groups responsible for interaction with the trans-activator protein Tat, including conformations similar to the previously characterized bound-state conformation. These results demonstrate the utility of RDC-NMR for simultaneously characterizing RNA tertiary dynamics and average conformation, and indicate an avenue for TAR complex formation involving tertiary structure capture. Copyright 2001 Academic Press.

  19. Dipolar versus octupolar triphenylamine-based fluorescent organic nanoparticles as brilliant one- and two-photon emitters for (bio)imaging.

    Science.gov (United States)

    Parthasarathy, Venkatakrishnan; Fery-Forgues, Suzanne; Campioli, Elisa; Recher, Gaëlle; Terenziani, Francesca; Blanchard-Desce, Mireille

    2011-11-18

    Two related triphenylamine-based dipolar and octupolar fluorophores are used to prepare aqueous suspensions of fluorescent organic nanoparticles (FONs) via the reprecipitation method. The obtained spherical nanoparticles (30-40 nm in diameter) are fluorescent in aqueous solution (up to 15% fluorescence quantum yield) and exhibit extremely high one- and two-photon brightness, superior to those obtained for quantum dots. Despite the two chromophores showing similar fluorescence in solution, the fluorescence of FONs made from the octupolar derivative is significantly red-shifted compared to that generated by the dipolar FONs. In addition, the maximum two-photon absorption cross section of the FONs made from the octupolar derivative is 55% larger than that of the dipolar derivative FONs. The experimental observations provide evidence that the different molecular shape (rodlike versus three-branched) and charge distribution (dipolar versus octupolar) of the two chromophores strongly affect the packing inside the nanoparticles as well as their spectroscopic properties and colloidal stability in pure water. The use of these FONs as probes for biphotonic in-vivo imaging is investigated on Xenopus laevis tadpoles to test their utilization for angiography. When using FONs made from the octupolar dye, the formation of microagglomerates (2-5 μm scale) is observed in vivo, with subsequent lethal occlusion of the blood vessels. Conversely, the nanoparticles of the dipolar dye allow acute imaging of blood vessels thanks to their suitable size and brightness, while no toxic effect is observed. Such a goal cannot be achieved with the dissolved dye, which permeates the vessel walls. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Inclusion Compound Based Approach to Forming Arrays of Artificial Dipolar Molecular Rotors: A Search for Optimal Rotor Structures

    Czech Academy of Sciences Publication Activity Database

    Kobr, L.; Zhao, K.; Shen, X.; Shoemaker, R. K.; Rogers, C. T.; Michl, Josef

    2013-01-01

    Roč. 25, č. 3 (2013), s. 443-448 ISSN 0935-9648 EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Grant - others:NSF(US) CHE 0848663 Institutional support: RVO:61388963 Keywords : inclusion compounds * molecular rotors * ferroelectricity * two-dimensional arrays Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 15.409, year: 2013

  1. Sequential backbone assignment based on dipolar amide-to-amide correlation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, ShengQi; Grohe, Kristof; Rovó, Petra; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus, E-mail: rali@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department for NMR-Based Structural Biology (Germany)

    2015-07-15

    Proton detection in solid-state NMR has seen a tremendous increase in popularity in the last years. New experimental techniques allow to exploit protons as an additional source of information on structure, dynamics, and protein interactions with their surroundings. In addition, sensitivity is mostly improved and ambiguity in assignment experiments reduced. We show here that, in the solid state, sequential amide-to-amide correlations turn out to be an excellent, complementary way to exploit amide shifts for unambiguous backbone assignment. For a general assessment, we compare amide-to-amide experiments with the more common {sup 13}C-shift-based methods. Exploiting efficient CP magnetization transfers rather than less efficient INEPT periods, our results suggest that the approach is very feasible for solid-state NMR.

  2. Sequential backbone assignment based on dipolar amide-to-amide correlation experiments

    International Nuclear Information System (INIS)

    Xiang, ShengQi; Grohe, Kristof; Rovó, Petra; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus

    2015-01-01

    Proton detection in solid-state NMR has seen a tremendous increase in popularity in the last years. New experimental techniques allow to exploit protons as an additional source of information on structure, dynamics, and protein interactions with their surroundings. In addition, sensitivity is mostly improved and ambiguity in assignment experiments reduced. We show here that, in the solid state, sequential amide-to-amide correlations turn out to be an excellent, complementary way to exploit amide shifts for unambiguous backbone assignment. For a general assessment, we compare amide-to-amide experiments with the more common 13 C-shift-based methods. Exploiting efficient CP magnetization transfers rather than less efficient INEPT periods, our results suggest that the approach is very feasible for solid-state NMR

  3. Synchronization of spin torque nano-oscillators through dipolar interactions

    International Nuclear Information System (INIS)

    Chen, Hao-Hsuan; Wu, Jong-Ching; Horng, Lance; Lee, Ching-Ming; Chang, Ching-Ray; Chang, Jui-Hang

    2014-01-01

    In an array of spin-torque nano-oscillators (STNOs) that combine a perpendicular polarized fixed layer with strong in-plane anisotropy in the free layers, magnetic dipolar interactions can effectively phase-lock the array, thus further enhancing the power of the output microwave signals. We perform a qualitative analysis of the synchronization of an array based on the Landau-Lifshitz-Gilbert equation, with a spin-transfer torque that assumes strong in-plane anisotropy. Finally, we present the numerical results for four coupled STNOs to provide further evidence for the proposed theory

  4. Synchronization of spin torque nano-oscillators through dipolar interactions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hao-Hsuan, E-mail: d95222014@ntu.edu.tw; Wu, Jong-Ching, E-mail: phjcwu@cc.ncue.edu.tw; Horng, Lance [Department of Physics, National Changhua University of Education, Changhua 500, Taiwan (China); Lee, Ching-Ming [Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou, 64002, Taiwan (China); Chang, Ching-Ray, E-mail: crchang@phys.ntu.edu.tw; Chang, Jui-Hang [Department of Physics and Center for Quantum Sciences and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-04-07

    In an array of spin-torque nano-oscillators (STNOs) that combine a perpendicular polarized fixed layer with strong in-plane anisotropy in the free layers, magnetic dipolar interactions can effectively phase-lock the array, thus further enhancing the power of the output microwave signals. We perform a qualitative analysis of the synchronization of an array based on the Landau-Lifshitz-Gilbert equation, with a spin-transfer torque that assumes strong in-plane anisotropy. Finally, we present the numerical results for four coupled STNOs to provide further evidence for the proposed theory.

  5. Dipolar modulation of Large-Scale Structure

    Science.gov (United States)

    Yoon, Mijin

    For the last two decades, we have seen a drastic development of modern cosmology based on various observations such as the cosmic microwave background (CMB), type Ia supernovae, and baryonic acoustic oscillations (BAO). These observational evidences have led us to a great deal of consensus on the cosmological model so-called LambdaCDM and tight constraints on cosmological parameters consisting the model. On the other hand, the advancement in cosmology relies on the cosmological principle: the universe is isotropic and homogeneous on large scales. Testing these fundamental assumptions is crucial and will soon become possible given the planned observations ahead. Dipolar modulation is the largest angular anisotropy of the sky, which is quantified by its direction and amplitude. We measured a huge dipolar modulation in CMB, which mainly originated from our solar system's motion relative to CMB rest frame. However, we have not yet acquired consistent measurements of dipolar modulations in large-scale structure (LSS), as they require large sky coverage and a number of well-identified objects. In this thesis, we explore measurement of dipolar modulation in number counts of LSS objects as a test of statistical isotropy. This thesis is based on two papers that were published in peer-reviewed journals. In Chapter 2 [Yoon et al., 2014], we measured a dipolar modulation in number counts of WISE matched with 2MASS sources. In Chapter 3 [Yoon & Huterer, 2015], we investigated requirements for detection of kinematic dipole in future surveys.

  6. Exact Solutions for Internuclear Vectors and Backbone Dihedral Angles from NH Residual Dipolar Couplings in Two Media, and their Application in a Systematic Search Algorithm for Determining Protein Backbone Structure

    International Nuclear Information System (INIS)

    Wang Lincong; Donald, Bruce Randall

    2004-01-01

    We have derived a quartic equation for computing the direction of an internuclear vector from residual dipolar couplings (RDCs) measured in two aligning media, and two simple trigonometric equations for computing the backbone (φ,ψ) angles from two backbone vectors in consecutive peptide planes. These equations make it possible to compute, exactly and in constant time, the backbone (φ,ψ) angles for a residue from RDCs in two media on any single backbone vector type. Building upon these exact solutions we have designed a novel algorithm for determining a protein backbone substructure consisting of α-helices and β-sheets. Our algorithm employs a systematic search technique to refine the conformation of both α-helices and β-sheets and to determine their orientations using exclusively the angular restraints from RDCs. The algorithm computes the backbone substructure employing very sparse distance restraints between pairs of α-helices and β-sheets refined by the systematic search. The algorithm has been demonstrated on the protein human ubiquitin using only backbone NH RDCs, plus twelve hydrogen bonds and four NOE distance restraints. Further, our results show that both the global orientations and the conformations of α-helices and β-strands can be determined with high accuracy using only two RDCs per residue. The algorithm requires, as its input, backbone resonance assignments, the identification of α-helices and β-sheets as well as sparse NOE distance and hydrogen bond restraints.Abbreviations: NMR - nuclear magnetic resonance; RDC - residual dipolar coupling; NOE - nuclear Overhauser effect; SVD - singular value decomposition; DFS - depth-first search; RMSD - root mean square deviation; POF - principal order frame; PDB - protein data bank; SA - simulated annealing; MD - molecular dynamics

  7. Independent EEG sources are dipolar.

    Directory of Open Access Journals (Sweden)

    Arnaud Delorme

    Full Text Available Independent component analysis (ICA and blind source separation (BSS methods are increasingly used to separate individual brain and non-brain source signals mixed by volume conduction in electroencephalographic (EEG and other electrophysiological recordings. We compared results of decomposing thirteen 71-channel human scalp EEG datasets by 22 ICA and BSS algorithms, assessing the pairwise mutual information (PMI in scalp channel pairs, the remaining PMI in component pairs, the overall mutual information reduction (MIR effected by each decomposition, and decomposition 'dipolarity' defined as the number of component scalp maps matching the projection of a single equivalent dipole with less than a given residual variance. The least well-performing algorithm was principal component analysis (PCA; best performing were AMICA and other likelihood/mutual information based ICA methods. Though these and other commonly-used decomposition methods returned many similar components, across 18 ICA/BSS algorithms mean dipolarity varied linearly with both MIR and with PMI remaining between the resulting component time courses, a result compatible with an interpretation of many maximally independent EEG components as being volume-conducted projections of partially-synchronous local cortical field activity within single compact cortical domains. To encourage further method comparisons, the data and software used to prepare the results have been made available (http://sccn.ucsd.edu/wiki/BSSComparison.

  8. Reactive Energetic Plasticizers Utilizing Cu-Free Azide-Alkyne 1,3-Dipolar Cycloaddition for In-Situ Preparation of Poly(THF-co-GAP-Based Polyurethane Energetic Binders

    Directory of Open Access Journals (Sweden)

    Mingyang Ma

    2018-05-01

    Full Text Available Reactive energetic plasticizers (REPs coupled with hydroxy-telechelic poly(glycidyl azide-co-tetrahydrofuran (PGT-based energetic polyurethane (PU binders for use in solid propellants and plastic-bonded explosives (PBXs were investigated. The generation of gem-dinitro REPs along with a terminal alkyne stemmed from a series of finely designed approaches to not only satisfy common demands as conventional energetic plasticizers, but also to prevent the migration of plasticizers. The miscibility and rheological behavior of a binary mixture of PGT/REP with various REP fractions were quantitatively determined by differential scanning calorimetry (DSC and rheometer, respectively, highlighting the promising performance of REPs in the formulation process. The kinetics on the distinct reactivity of propargyl vs. 3-butynyl species of REPs towards the azide group of the PGT prepolymer in terms of Cu-free azide-alkyne 1,3-dipolar cycloaddition (1,3-DPCA was studied by monitoring 1H nuclear magnetic resonance spectroscopy and analyzing the activation energies (Ea obtained using DSC. The thermal stability of the finally cured energetic binders with the incorporation of REPs indicated that the thermal stability of the REP/PGT-based PUs was maintained independently of the REP content. The tensile strength and modulus of the PUs increased with an increase in the REP content. In addition, the energetic performance and sensitivity of REP and REP triazole species was predicted.

  9. Accurate Determination of Leucine and Valine Side-chain Conformations using U-[15N/13C/2H]/[1H-(methine/methyl)-Leu/Val] Isotope Labeling, NOE Pattern Recognition, and Methine Cγ-Hγ/Cβ-Hβ Residual Dipolar Couplings

    International Nuclear Information System (INIS)

    Tang, Chun; Iwahara, Junji; Clore, G. Marius

    2005-01-01

    An isotope labeling scheme is described in which specific protonation of methine and methyl protons of leucine and valine is obtained on a 15 N/ 13 C labeled background with uniform deuteration of all other non-exchangeable protons. The presence of a protonated methine group has little effect on the favorable relaxation properties of the methyl protons of Leu and Val. This labeling scheme permits the rotameric state of leucine side-chains to be readily determined by simple inspection of the pattern of Hγ(i)-H N (i) and Hγ(i)-H N (i+1) NOEs in a 3D 15 N-separated NOE spectrum free of complications arising from spectral overlap and spin-diffusion. In addition, one-bond residual dipolar couplings for the methine 13 C- 1 H bond vectors of Leu and Val can be accurately determined from an intensity J-modulated constant-time HCCH-COSY experiment and used to accurately orient the side-chains of Leu and Val. Incorporation of these data into structure refinement improves the accuracy with which the conformations of Leu and Val side-chains can be established. This is important to ensure optimal packing both within the protein core and at intermolecular interfaces. The impact of the method on protein structure determination is illustrated by application to enzyme IIA Chitobiose , a 34 kDa homotrimeric phosphotransferase protein

  10. Asymptotic behavior of local dipolar fields in thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, G.J., E-mail: gjb@phys.soton.ac.uk [School of Physics and Astronomy, University of Southampton, SO17 1BJ (United Kingdom); Stenning, G.B.G., E-mail: Gerrit.vanderlaan@diamond.ac.uk [Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE (United Kingdom); Laan, G. van der, E-mail: gavin.stenning@stfc.ac.uk [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom)

    2016-10-15

    A simple method, based on layer by layer direct summation, is used to determine the local dipolar fields in uniformly magnetized thin films. The results show that the dipolar constants converge ~1/m where the number of spins in a square film is given by (2m+1){sup 2}. Dipolar field results for sc, bcc, fcc, and hexagonal lattices are presented and discussed. The results can be used to calculate local dipolar fields in films with either ferromagnetic, antiferromagnetic, spiral, exponential decay behavior, provided the magnetic order only changes normal to the film. Differences between the atomistic (local fields) and macroscopic fields (Maxwellian) are also examined. For the latter, the macro B-field inside the film is uniform and falls to zero sharply outside, in accord with Maxwell boundary conditions. In contrast, the local field for the atomistic point dipole model is highly non-linear inside and falls to zero at about three lattice spacing outside the film. Finally, it is argued that the continuum field B (used by the micromagnetic community) and the local field B{sub loc}(r) (used by the FMR community) will lead to differing values for the overall demagnetization energy. - Highlights: • Point-dipolar fields in uniformly magnetized thin films are characterized by just three numbers. • Maxwell's boundary condition is partially violated in the point-dipole approximation. • Asymptotic values of point dipolar fields in circular monolayers scale as π/r.

  11. Quantum states with topological properties via dipolar interactions

    Energy Technology Data Exchange (ETDEWEB)

    Peter, David

    2015-06-25

    This thesis proposes conceptually new ways to realize materials with topological properties by using dipole-dipole interactions. First, we study a system of ultracold dipolar fermions, where the relaxation mechanism of dipolar spins can be used to reach the quantum Hall regime. Second, in a system of polar molecules in an optical lattice, dipole-dipole interactions induce spin-orbit coupling terms for the rotational excitations. In combination with time-reversal symmetry breaking this leads to topological bands with Chern numbers greater than one.

  12. Synchronization of vortex-based spin torque nano-oscillators by magnetostatic coupling

    Energy Technology Data Exchange (ETDEWEB)

    Zaspel, C.E., E-mail: craig.zaspel@umwestern.edu

    2015-12-15

    Synchronization of two nanopillar oscillators driven by spin torque and coupled through the magnetic dipolar interaction. The dominant mode in each oscillator is gyrotropic motion of the vortex core in an elliptical orbit about the free layer disk center. The dynamic properties of this mode is investigated by solution the coupled Thiele equations with both nanopillar oscillators having identical dimensions, but with a current mismatch. It is noticed that there is a range in the current difference where the oscillators will be synchronized where the vortex gyrotropic motion will be frequency-locked with the radii of gyrotropic motion equal for both disks. There is, however, a phase shift between the gyrotropic motion with the smaller current disk lagging the higher current disk by a few degrees. - Highlights: • Vortex-based nanopillar oscillators re synchronized by the dipolar interaction. • There is a range of frequencies where both oscillators will frequency-locked. • There are upper and lower critical currents defining a locking range.

  13. Dipolar ferromagnets and glasses (invited)

    International Nuclear Information System (INIS)

    Rosenbaum, T.F.; Wu, W.; Ellman, B.; Yang, J.; Aeppli, G.; Reich, D.H.

    1991-01-01

    What is the ground state and what are the dynamics of 10 23 randomly distributed Ising spins? We have attempted to answer these questions through magnetic susceptibility, calorimetric, and neutron scattering studies of the randomly diluted dipolar-coupled Ising magnet LiHo x Y 1-x F 4 . The material is ferromagnetic for dipole concentrations at least as low as x=0.46, with a Curie temperature obeying mean-field scaling relative to that of pure LiHoF 4 . In the dilute spin limit, an x=0.045 crystal shows very unusual glassy properties characterized by decreasing barriers to relaxation as T→0. Its properties are consistent with a single low degeneracy ground state with a large gap for excitations. A slightly more concentrated x=0.167 sample, however, supports a complex ground state with no appreciable gap, in accordance with prevailing theories of spin glasses. The underlying causes of such disparate behavior are discussed in terms of random clusters as probed by neutron studies of the x=0.167 sample. In addition to tracing the evolution of the glassy and ferromagnetic states with dipole concentration, we investigate the effects of a transverse magnetic field on the Ising spin glass, LiHo 0.167 Y 0.833 F 4 . The transverse field mixes the eigenfunctions of the ground-state Ising doublet with the otherwise inaccessible excited-state levels. We observe a rapid decrease in the characteristic relaxation times, large changes in the spectral form of the relaxation, and a depression of the spin-glass transition temperature with the addition of quantum fluctuations

  14. Propagation of Dipolarization Signatures Observed by the Van Allen Probes in the Inner Magnetosphere

    Science.gov (United States)

    Ohtani, S.; Motoba, T.; Gkioulidou, M.; Takahashi, K.; Kletzing, C.

    2017-12-01

    Dipolarization, the change of the local magnetic field from a stretched to a more dipolar configuration, is one of the most fundamental processes of magnetospheric physics. It is especially critical for the dynamics of the inner magnetosphere. The associated electric field accelerates ions and electrons and transports them closer to Earth. Such injected ions intensify the ring current, and electrons constitute the seed population of the radiation belt. Those ions and electrons may also excite various waves that play important roles in the enhancement and loss of the radiation belt electrons. Despite such critical consequences, the general characteristics of dipolarization in the inner magnetosphere still remain to be understood. The Van Allen Probes mission, which consists of two probes that orbit through the equatorial region of the inner magnetosphere, provides an ideal opportunity to examine dipolarization signatures in the core of the ring current. In the present study we investigate the spatial expansion of the dipolarization region by examining the correlation and time delay of dipolarization signatures observed by the two probes. Whereas in general it requires three-point measurements to deduce the propagation of a signal on a certain plane, we statically examined the observed time delays and found that dipolarization signatures tend to propagate radially inward as well as away from midnight. In this paper we address the propagation of dipolarization signatures quantitatively and compare with the propagation velocities reported previously based on observations made farther away from Earth. We also discuss how often and under what conditions the dipolarization region expands.

  15. Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids

    International Nuclear Information System (INIS)

    Abedinpour, Saeed H.; Asgari, Reza; Tanatar, B.; Polini, Marco

    2014-01-01

    We study the ground-state properties of a two-dimensional spin-polarized fluid of dipolar fermions within the Euler–Lagrange Fermi-hypernetted-chain approximation. Our method is based on the solution of a scattering Schrödinger equation for the “pair amplitude” √(g(r)), where g(r) is the pair distribution function. A key ingredient in our theory is the effective pair potential, which includes a bosonic term from Jastrow–Feenberg correlations and a fermionic contribution from kinetic energy and exchange, which is tailored to reproduce the Hartree–Fock limit at weak coupling. Very good agreement with recent results based on quantum Monte Carlo simulations is achieved over a wide range of coupling constants up to the liquid-to-crystal quantum phase transition. Using the fluctuation–dissipation theorem and a static approximation for the effective inter-particle interactions, we calculate the dynamical density–density response function, and furthermore demonstrate that an undamped zero-sound mode exists for any value of the interaction strength, down to infinitesimally weak couplings. -- Highlights: •We have studied the ground state properties of a strongly correlated two-dimensional fluid of dipolar fermions. •We have calculated the effective inter-particle interaction and the dynamical density–density response function. •We have shown that an undamped zero sound mode exists at any value of the interaction strength

  16. Dipolar and spinor bosonic systems

    Science.gov (United States)

    Yukalov, V. I.

    2018-05-01

    The main properties and methods of describing dipolar and spinor atomic systems, composed of bosonic atoms or molecules, are reviewed. The general approach for the correct treatment of Bose-condensed atomic systems with nonlocal interaction potentials is explained. The approach is applied to Bose-condensed systems with dipolar interaction potentials. The properties of systems with spinor interaction potentials are described. Trapped atoms and atoms in optical lattices are considered. Effective spin Hamiltonians for atoms in optical lattices are derived. The possibility of spintronics with cold atom is emphasized. The present review differs from the previous review articles by concentrating on a thorough presentation of basic theoretical points, helping the reader to better follow mathematical details and to make clearer physical conclusions.

  17. Dipolar quantum gases of erbium

    International Nuclear Information System (INIS)

    Frisch, A.

    2014-01-01

    Since the preparation of the first Bose-Einstein condensate about two decades ago and the first degenerate Fermi gas following four years later a plethora of fascinating quantum phenomena have been explored. The vast majority of experiments focused on quantum degenerate atomic gases with short-range contact interaction between particles. Atomic species with large magnetic dipole moments, such as chromium, dysprosium, and erbium, offer unique possibilities to investigate phenomena arising from dipolar interaction. This kind of interaction is not only long-range but also anisotropic in character and imprints qualitatively novel features on the system. Prominent examples are the d-wave collapse of a dipolar Bose-Einstein condensate of chromium atoms realized by the group in Stuttgart, the spin magnetization and demagnetization dynamics observed by groups in Stuttgart, Paris, and Stanford, and the deformation of the Fermi surface observed by our group in Innsbruck. This thesis reports on the creation and study of the first Bose-Einstein condensate and degenerate Fermi gas of erbium atoms. Erbium belongs to the lanthanide group of elements and has a large magnetic moment of seven Bohr magneton. In particular, this thesis describes the experimental apparatus and the sequence for producing a dipolar quantum gas. There is an emphasis on the production of the narrow-line magneto-optical trap of erbium since this represents a very efficient and robust laser-cooling scheme that greatly simplifies the experimental procedure. After describing the experimental setup this thesis focuses on several fundamental questions related to the dipolar character of erbium and to its lanthanide nature. A first set of studies centers on the scattering properties of ultracold erbium atoms, including the elastic and the inelastic cross section and the spectrum of Feshbach resonances. Specifically, we observe that identical dipolar fermions do collide and rethermalize even at low temperatures

  18. Dipolar and quadrupolar defects in a transport line

    International Nuclear Information System (INIS)

    Leleux, G.; Nghiem, P.

    1991-01-01

    The defects on a transport line of linear accelerator are studied. A transport line where the elements are influenced by the design or position defects is analyzed. Only dipolar and quadrupolar defects are considered, and the coupling betwen transversal motions are excluded. The data from the literature and those calculated by transfer matrices are compared. The defects on a line are considered from an analytical point of view. Closed optical structures are also studied [fr

  19. Dipolar dark matter with massive bigravity

    International Nuclear Information System (INIS)

    Blanchet, Luc; Heisenberg, Lavinia

    2015-01-01

    Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model

  20. Optical switching of nuclear spin-spin couplings in semiconductors.

    Science.gov (United States)

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

    2011-07-05

    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings.

  1. Optical switching of nuclear spin–spin couplings in semiconductors

    Science.gov (United States)

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

    2011-01-01

    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear–spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings. PMID:21730962

  2. Thermodynamics of Dipolar Chain Systems

    DEFF Research Database (Denmark)

    R. Armstrong, J.; Zinner, Nikolaj Thomas; V. Fedorov, D.

    2012-01-01

    The thermodynamics of a quantum system of layers containing perpendicularly oriented dipolar molecules is studied within an oscillator approximation for both bosonic and fermionic species. The system is assumed to be built from chains with one molecule in each layer. We consider the effects...... numerically. Our findings indicate that thermodynamic observables, such as the heat capacity, can be used to probe the signatures of the intralayer interaction between chains. This should be relevant for near future experiments on polar molecules with strong dipole moments....

  3. Thermal entanglement and teleportation in a dipolar interacting system

    Energy Technology Data Exchange (ETDEWEB)

    Castro, C.S., E-mail: ccastro@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, RJ (Brazil); Centro de Formação de Professores, Universidade Federal do Recôncavo da Bahia, Av. Nestor de Mello Pita, n. 535, 45.300-000 Amargosa, BA (Brazil); Duarte, O.S.; Pires, D.P.; Soares-Pinto, D.O. [Instituto de Física de São Carlos, Universidade de São Paulo, P.O. Box 369, São Carlos, 13560-970 SP (Brazil); Reis, M.S. [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, RJ (Brazil)

    2016-04-22

    Quantum teleportation, which depends on entangled states, is a fascinating subject and an important branch of quantum information processing. The present work reports the use of a dipolar spin thermal system as a noisy quantum channel to perform quantum teleportation. Non-locality, tested by violation of Bell's inequality and thermal entanglement, measured by negativity, shows that for the present model all entangled states, even those that do not violate Bell's inequality, are useful for teleportation. - Highlights: • The effects of a dipolar interaction between two spins on their degree of entanglement and non-locality is reported. • The model presents some degree of non-locality and entanglement at a given coupling parameters. • It is shown how the magnetic anisotropies can influence the fidelity of teleportation.

  4. Dipolarization Fronts from Reconnection Onset

    Science.gov (United States)

    Sitnov, M. I.; Swisdak, M. M.; Merkin, V. G.; Buzulukova, N.; Moore, T. E.

    2012-12-01

    Dipolarization fronts observed in the magnetotail are often viewed as signatures of bursty magnetic reconnection. However, until recently spontaneous reconnection was considered to be fully prohibited in the magnetotail geometry because of the linear stability of the ion tearing mode. Recent theoretical studies showed that spontaneous reconnection could be possible in the magnetotail geometries with the accumulation of magnetic flux at the tailward end of the thin current sheet, a distinctive feature of the magnetotail prior to substorm onset. That result was confirmed by open-boundary full-particle simulations of 2D current sheet equilibria, where two magnetotails were separated by an equilibrium X-line and weak external electric field was imposed to nudge the system toward the instability threshold. To investigate the roles of the equilibrium X-line, driving electric field and other parameters in the reconnection onset process we performed a set of 2D PIC runs with different initial settings. The investigated parameter space includes the critical current sheet thickness, flux tube volume per unit magnetic flux and the north-south component of the magnetic field. Such an investigation is critically important for the implementation of kinetic reconnection onset criteria into global MHD codes. The results are compared with Geotail visualization of the magnetotail during substorms, as well as Cluster and THEMIS observations of dipolarization fronts.

  5. Designing Hysteresis with Dipolar Chains

    Science.gov (United States)

    Concha, Andrés; Aguayo, David; Mellado, Paula

    2018-04-01

    Materials that have hysteretic response to an external field are essential in modern information storage and processing technologies. A myriad of magnetization curves of several natural and artificial materials have previously been measured and each has found a particular mechanism that accounts for it. However, a phenomenological model that captures all the hysteresis loops and at the same time provides a simple way to design the magnetic response of a material while remaining minimal is missing. Here, we propose and experimentally demonstrate an elementary method to engineer hysteresis loops in metamaterials built out of dipolar chains. We show that by tuning the interactions of the system and its geometry we can shape the hysteresis loop which allows for the design of the softness of a magnetic material at will. Additionally, this mechanism allows for the control of the number of loops aimed to realize multiple-valued logic technologies. Our findings pave the way for the rational design of hysteretical responses in a variety of physical systems such as dipolar cold atoms, ferroelectrics, or artificial magnetic lattices, among others.

  6. Acceleration and Precipitation of Electrons during Substorm Dipolarization Events

    Science.gov (United States)

    Ashour-Abdalla, Maha; Richard, Robert; Donovan, Eric; Zhou, Meng; Goldstein, Mevlyn; El-Alaoui, Mostafa; Schriver, David; Walker, Raymond

    Observations and modeling have established that during geomagnetically disturbed times the Earth’s magnetotail goes through large scale changes that result in enhanced electron precipitation into the ionosphere and earthward propagating dipolarization fronts that contain highly energized plasma. Such events originate near reconnection regions in the magnetotail at about 20-30 R_E down tail. As the dipolarization fronts propagate earthward, strong acceleration of both ions and electrons occurs due to a combination of non-adiabatic and adiabatic (betatron and Fermi) acceleration, with particle energies reaching up to 100 keV within the dipolarization front. One consequence of the plasma transport that occurs during these events is direct electron precipitation into the ionosphere, which form auroral precipitation. Using global kinetic simulations along with spacecraft and ground-based data, causes of electron precipitation are determined during well-documented, disturbed events. It is found that precipitation of keV electrons in the pre-midnight sector at latitudes around 70(°) occur due to two distinct physical processes: (1) higher latitude (≥72(°) ) precipitation due to electrons that undergo relatively rapid non-adiabatic pitch angle scattering into the loss cone just earthward of the reconnection region at around 20 R_E downtail, and (2) lower latitude (≤72(°) ) precipitation due to electrons that are more gradually accelerated primarily parallel to the geomagnetic field during its bounce motion by Fermi acceleration and enter the loss cone much closer to the Earth at 10-15 R_E, somewhat tailward of the dipolarization front. As the dipolarization fronts propagate earthward, the electron precipitation shifts to lower latitudes and occurs over a wider region in the auroral ionosphere. Our results show a direct connection between electron acceleration in the magnetotail and electron precipitation in the ionosphere during disturbed times. The electron

  7. Strategic Coupling Based on Natural Resources

    DEFF Research Database (Denmark)

    Hauge, Mads Martinus

    The topic of this thesis is the resourced-based industrialization of the Mekong River Delta (MRD) Region of Vietnam. It shows how a region is linked with the world market and how settlements and living conditions are being transformed as part of a globalized regional development. A modular theory......-building approach rooted in the Global Production Network (GPN) framework constitutes the analytical approach to the thesis, providing pertinent conceptualizations to explore and discuss how a globalized regional development unfolds. The main theoretical concept of the thesis is that of strategic coupling......, an established concept within the GPN framework that explores and explains how local assets are molded to complement the needs of the global market. However, existing applications of the notion of strategic coupling do not cover the situation in which a resource-based economy is coupled with the world market...

  8. Equilibrium phases of dipolar lattice bosons in the presence of random diagonal disorder

    Science.gov (United States)

    Zhang, C.; Safavi-Naini, A.; Capogrosso-Sansone, B.

    2018-01-01

    Ultracold gases offer an unprecedented opportunity to engineer disorder and interactions in a controlled manner. In an effort to understand the interplay between disorder, dipolar interactions, and quantum degeneracy, we study two-dimensional hard-core dipolar lattice bosons in the presence of on-site bound disorder. Our results are based on large-scale path-integral quantum Monte Carlo simulations by the worm algorithm. We study the ground-state phase diagram at a fixed half-integer filling factor for which the clean system is either a superfluid at a lower dipolar interaction strength or a checkerboard solid at a larger dipolar interaction strength. We find that, even for weak dipolar interactions, superfluidity is destroyed in favor of a Bose glass at a relatively low disorder strength. Interestingly, in the presence of disorder, superfluidity persists for values of the dipolar interaction strength for which the clean system is a checkerboard solid. At a fixed disorder strength, as the dipolar interaction is increased, superfluidity is destroyed in favor of a Bose glass. As the interaction is further increased, the system eventually develops extended checkerboard patterns in the density distribution. Due to the presence of disorder, though, grain boundaries and defects, responsible for a finite residual compressibility, are present in the density distribution. Finally, we study the robustness of the superfluid phase against thermal fluctuations.

  9. Thermodynamics of Dipolar Chain Systems

    International Nuclear Information System (INIS)

    Armstrong, J.R.; Zinner, N.T.; Fedorov, D.V.; Jensen, A.S.

    2013-01-01

    The thermodynamics of a quantum system of layers containing perpendicularly oriented dipolar molecules is studied within an oscillator approximation for both bosonic and fermionic species. The system is assumed to be built from chains with one molecule in each layer. We consider the effects of the intralayer repulsion and quantum statistical requirements in systems with more than one chain. Specifically, we consider the case of two chains and solve the problem analytically within the harmonic Hamiltonian approach which is accurate for large dipole moments. The case of three chains is calculated numerically. Our findings indicate that thermodynamic observables, such as the heat capacity, can be used to probe the signatures of the intralayer interaction between chains. This should be relevant for near future experiments on polar molecules with strong dipole moments. (author)

  10. Nuclear magnetic relaxation by the dipolar EMOR mechanism: General theory with applications to two-spin systems.

    Science.gov (United States)

    Chang, Zhiwei; Halle, Bertil

    2016-02-28

    In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. We have embarked on a systematic program to develop, from the stochastic Liouville equation, a general and rigorous theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole coupling strengths, and Larmor frequencies. Here, we present a general theoretical framework applicable to spin systems of arbitrary size with symmetric or asymmetric exchange. So far, the dipolar EMOR theory is only available for a two-spin system with symmetric exchange. Asymmetric exchange, when the spin system is fragmented by the exchange, introduces new and unexpected phenomena. Notably, the anisotropic dipole couplings of non-exchanging spins break the axial symmetry in spin Liouville space, thereby opening up new relaxation channels in the locally anisotropic sites, including longitudinal-transverse cross relaxation. Such cross-mode relaxation operates only at low fields; at higher fields it becomes nonsecular, leading to an unusual inverted relaxation dispersion that splits the extreme-narrowing regime into two sub-regimes. The general dipolar EMOR theory is illustrated here by a detailed analysis of the asymmetric two-spin case, for which we present relaxation dispersion profiles over a wide range of conditions as well as analytical results for integral relaxation rates and time-dependent spin modes in the zero-field and motional-narrowing regimes. The general theoretical framework presented here will enable a quantitative analysis of frequency-dependent water-proton longitudinal relaxation in model systems with immobilized macromolecules and, ultimately, will provide a rigorous link between relaxation-based magnetic resonance image contrast and molecular parameters.

  11. Evaluation of magnetic dipolar terms in molecules

    International Nuclear Information System (INIS)

    Muniz, R.B.; Brandi, H.S.; Maffeo, B.

    1977-01-01

    The magnetic dipolar parameter b for several values of the internuclear distance in the molecule F 2 - is evaluated. The difficulties appearing in the calculations are discussed and a manner to overcome them is presented [pt

  12. Imaging using long range dipolar field effects

    International Nuclear Information System (INIS)

    Gutteridge, Sarah

    2002-01-01

    The work in this thesis has been undertaken by the author, except where indicated in reference, within the Magnetic Resonance Centre, at the University of Nottingham during the period from October 1998 to March 2001. This thesis details the different characteristics of the long range dipolar field and its application to magnetic resonance imaging. The long range dipolar field is usually neglected in nuclear magnetic resonance experiments, as molecular tumbling decouples its effect at short distances. However, in highly polarised samples residual long range components have a significant effect on the evolution of the magnetisation, giving rise to multiple spin echoes and unexpected quantum coherences. Three applications utilising these dipolar field effects are documented in this thesis. The first demonstrates the spatial sensitivity of the signal generated via dipolar field effects in structured liquid state samples. The second utilises the signal produced by the dipolar field to create proton spin density maps. These maps directly yield an absolute value for the water content of the sample that is unaffected by relaxation and any RF inhomogeneity or calibration errors in the radio frequency pulses applied. It has also been suggested that the signal generated by dipolar field effects may provide novel contrast in functional magnetic resonance imaging. In the third application, the effects of microscopic susceptibility variation on the signal are studied and the relaxation rate of the signal is compared to that of a conventional spin echo. (author)

  13. Ground state configurations in antiferromagnetic ultrathin films with dipolar anisotropy

    International Nuclear Information System (INIS)

    León, H.

    2013-01-01

    The formalism developed in a previous work to calculate the dipolar energy in quasi-two-dimensional crystals with ferromagnetic order is now extended to collinear antiferromagnetic order. Numerical calculations of the dipolar energy are carried out for systems with tetragonally distorted fcc [001] structures, the case of NiO and MnO ultrathin film grown in non-magnetic substrates, where the magnetic phase is a consequence of superexchange and dipolar interactions. The employed approximation allows to demonstrate that dipolar coupling between atomic layers is responsible for the orientation of the magnetization when it differs from the one in a single layer. The ground state energy of a given NiO or MnO film is found to depend not only on the strain, but also on how much the interlayer separation and the 2D lattice constant are changed with respect to the ideal values corresponding to the non-distorted cubic structure. Nevertheless, it is shown that the orientation of the magnetization in the magnetic phase of any of these films is determined by the strain exclusively. A striped phase with the magnetization along the [112 ¯ ] direction appears as the ground state configuration of NiO and MnO ultrathin films. In films with equally oriented stripes along the layers this magnetic phase is twofold degenerate, while in films with multidomain layers it is eightfold degenerate. These results are not in contradiction with experimentally observed out-of-plane or in-plane magnetization of striped phases in NiO and MnO ultrathin films. - Highlights: ► Dipolar energy in collinear antiferromagnetic ultrathin films is calculated. ► Numerical results are presented for distorted fcc [001] structures. ► The lowest energy of a system depends on how the tetragonal distortion is achieved. ► A striped phase with magnetization in the [112 ¯ ] direction is the ground state. ► In multidomain NiO and MnO films it is eightfold degenerate.

  14. AC susceptibility as a tool to probe the dipolar interaction in magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Gabriel T., E-mail: gtlandi@gmail.com [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Arantes, Fabiana R. [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Cornejo, Daniel R. [Instituto de Física da Universidade de São Paulo, São Paulo 05508-090 (Brazil); Bakuzis, Andris F. [Instituto de Física, Universidade Federal de Goiás, 74690-900 Goiânia-GO (Brazil); Andreu, Irene; Natividad, Eva [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Zaragoza 50018 (Spain)

    2017-01-01

    The dipolar interaction is known to substantially affect the properties of magnetic nanoparticles. This is particularly important when the particles are kept in a fluid suspension or packed within nano-carriers. In addition to its usual long-range nature, in these cases the dipolar interaction may also induce the formation of clusters of particles, thereby strongly modifying their magnetic anisotropies. In this paper we show how AC susceptibility may be used to obtain information regarding the influence of the dipolar interaction in a sample. We develop a model which includes both aspects of the dipolar interaction and may be fitted directly to the susceptibility data. The usual long-range nature of the interaction is implemented using a mean-field approximation, whereas the particle-particle aggregation is modeled using a distribution of anisotropy constants. The model is then applied to two samples studied at different concentrations. One consists of spherical magnetite nanoparticles dispersed in oil and the other of cubic magnetite nanoparticles embedded on polymeric nanospheres. We also introduce a simple technique to address the presence of the dipolar interaction in a given sample, based on the height of the AC susceptibility peaks for different driving frequencies. - Highlights: We discuss the importance of the dipolar interaction in magnetic nanoparticle samples. It is shown that AC susceptibility may be used to estimate the extent of this interaction. We develop a model that accounts for particle aggregation. The theoretical model is then fitted to distinct magnetite samples.

  15. Dipolar Antiferromagnetism and Quantum Criticality in LiErF4

    International Nuclear Information System (INIS)

    Kraemer, Conradin; Nikseresht, Neda; Piatek, Julian; Tsyrulin, Nikolay; Piazza, Bastien; Kiefer, Klaus; Klemke, Bastian; Rosenbaum, Thomas; Aeppli, Gabriel; Gannarelli, Che; Prokes, Karel; Straessle, Thierry; Keller, Lukas; Zaharko, Oksana; Kraemer, Karl; Ronnow, Henrik

    2012-01-01

    Magnetism has been predicted to occur in systems in which dipolar interactions dominate exchange. We present neutron scattering, specific heat, and magnetic susceptibility data for LiErF 4 , establishing it as a model dipolar-coupled antiferromagnet with planar spin-anisotropy and a quantum phase transition in applied field H c# parallel# = 4.0 ± 0.1 kilo-oersteds. We discovered non-mean-field critical scaling for the classical phase transition at the antiferromagnetic transition temperature that is consistent with the two-dimensional XY/h 4 universality class; in accord with this, the quantum phase transition at H c exhibits three-dimensional classical behavior. The effective dimensional reduction may be a consequence of the intrinsic frustrated nature of the dipolar interaction, which strengthens the role of fluctuations.

  16. Finite-size corrections in simulation of dipolar fluids

    Science.gov (United States)

    Belloni, Luc; Puibasset, Joël

    2017-12-01

    Monte Carlo simulations of dipolar fluids are performed at different numbers of particles N = 100-4000. For each size of the cubic cell, the non-spherically symmetric pair distribution function g(r,Ω) is accumulated in terms of projections gmnl(r) onto rotational invariants. The observed N dependence is in very good agreement with the theoretical predictions for the finite-size corrections of different origins: the explicit corrections due to the absence of fluctuations in the number of particles within the canonical simulation and the implicit corrections due to the coupling between the environment around a given particle and that around its images in the neighboring cells. The latter dominates in fluids of strong dipolar coupling characterized by low compressibility and high dielectric constant. The ability to clean with great precision the simulation data from these corrections combined with the use of very powerful anisotropic integral equation techniques means that exact correlation functions both in real and Fourier spaces, Kirkwood-Buff integrals, and bridge functions can be derived from box sizes as small as N ≈ 100, even with existing long-range tails. In the presence of dielectric discontinuity with the external medium surrounding the central box and its replica within the Ewald treatment of the Coulombic interactions, the 1/N dependence of the gmnl(r) is shown to disagree with the, yet well-accepted, prediction of the literature.

  17. Nuclear magnetic relaxation by the dipolar EMOR mechanism: Multi-spin systems

    Science.gov (United States)

    Chang, Zhiwei; Halle, Bertil

    2017-08-01

    In aqueous systems with immobilized macromolecules, including biological tissues, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. Starting from the stochastic Liouville equation, we have previously developed a rigorous EMOR relaxation theory for dipole-coupled two-spin and three-spin systems. Here, we extend the stochastic Liouville theory to four-spin systems and use these exact results as a guide for constructing an approximate multi-spin theory, valid for spin systems of arbitrary size. This so-called generalized stochastic Redfield equation (GSRE) theory includes the effects of longitudinal-transverse cross-mode relaxation, which gives rise to an inverted step in the relaxation dispersion profile, and coherent spin mode transfer among solid-like spins, which may be regarded as generalized spin diffusion. The GSRE theory is compared to an existing theory, based on the extended Solomon equations, which does not incorporate these phenomena. Relaxation dispersion profiles are computed from the GSRE theory for systems of up to 16 protons, taken from protein crystal structures. These profiles span the range from the motional narrowing limit, where the coherent mode transfer plays a major role, to the ultra-slow motion limit, where the zero-field rate is closely related to the strong-collision limit of the dipolar relaxation rate. Although a quantitative analysis of experimental data is beyond the scope of this work, it is clear from the magnitude of the predicted relaxation rate and the shape of the relaxation dispersion profile that the dipolar EMOR mechanism is the principal cause of water-1H low-field longitudinal relaxation in aqueous systems of immobilized macromolecules, including soft biological tissues. The relaxation theory developed here therefore provides a basis for molecular-level interpretation of endogenous soft

  18. Mesh-based parallel code coupling interface

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K.; Steckel, B. (eds.) [GMD - Forschungszentrum Informationstechnik GmbH, St. Augustin (DE). Inst. fuer Algorithmen und Wissenschaftliches Rechnen (SCAI)

    2001-04-01

    MpCCI (mesh-based parallel code coupling interface) is an interface for multidisciplinary simulations. It provides industrial end-users as well as commercial code-owners with the facility to combine different simulation tools in one environment. Thereby new solutions for multidisciplinary problems will be created. This opens new application dimensions for existent simulation tools. This Book of Abstracts gives a short overview about ongoing activities in industry and research - all presented at the 2{sup nd} MpCCI User Forum in February 2001 at GMD Sankt Augustin. (orig.) [German] MpCCI (mesh-based parallel code coupling interface) definiert eine Schnittstelle fuer multidisziplinaere Simulationsanwendungen. Sowohl industriellen Anwender als auch kommerziellen Softwarehersteller wird mit MpCCI die Moeglichkeit gegeben, Simulationswerkzeuge unterschiedlicher Disziplinen miteinander zu koppeln. Dadurch entstehen neue Loesungen fuer multidisziplinaere Problemstellungen und fuer etablierte Simulationswerkzeuge ergeben sich neue Anwendungsfelder. Dieses Book of Abstracts bietet einen Ueberblick ueber zur Zeit laufende Arbeiten in der Industrie und in der Forschung, praesentiert auf dem 2{sup nd} MpCCI User Forum im Februar 2001 an der GMD Sankt Augustin. (orig.)

  19. Ultracold Dipolar Gases in Optical Lattices

    OpenAIRE

    Trefzger, C.; Menotti, C.; Capogrosso-Sansone, B.; Lewenstein, M.

    2011-01-01

    This tutorial is a theoretical work, in which we study the physics of ultra-cold dipolar bosonic gases in optical lattices. Such gases consist of bosonic atoms or molecules that interact via dipolar forces, and that are cooled below the quantum degeneracy temperature, typically in the nK range. When such a degenerate quantum gas is loaded into an optical lattice produced by standing waves of laser light, new kinds of physical phenomena occur. These systems realize then extended Hubbard-type m...

  20. Response of energetic particles to local magnetic dipolarization inside geosynchronous orbit

    Science.gov (United States)

    Motoba, T.; Ohtani, S.; Gkioulidou, M.; Takahashi, K.

    2017-12-01

    Magnetic field dipolarization and energetic particle injections are the most distinct phenomena observed in the inner magnetosphere during the substorm expansion phase. Compared to a wealth of knowledge about the phenomenology of magnetic dipolarizations and particle injections at/outside geosynchronous orbit (GEO), our understanding of them inside GEO remains incomplete because of a very limited number of previous studies. In the present study, we statistically examine the response of 1-1000 keV energetic particles to local magnetic dipolarization by performing a superposed epoch analysis of energetic particle fluxes with the zero epoch defined as the dipolarization onset times. Based on data from the Van Allen Probes tail seasons in 2012-2016, we identified a total of 97 magnetic dipolarization events which occurred closer to the magnetic equator (i.e., BH, which is antiparallel to the Earth's dipole axis, is the dominant component of the local magnetic field at least for 5 min before the onset). For major ion species (hydrogen, helium, and oxygen ions), the relative flux intensity to the pre-onset level increases at > 50 keV and decreases at inverse energy dispersion. For dipolarizations with strong impulsive westward electric fields, the relative electron flux intensity increases up to 5-10 times, in particular most significant at several tens of keV. This result suggests that the impulsive electric field acts as an efficient factor in the rapid energization of the tens-of-keV electrons. We also discuss how the response of energetic particles to dipolarization depends on MLT, radial distance, and pitch angle.

  1. Accurate Determination of Leucine and Valine Side-chain Conformations using U-[{sup 15}N/{sup 13}C/{sup 2}H]/[{sup 1}H-(methine/methyl)-Leu/Val] Isotope Labeling, NOE Pattern Recognition, and Methine C{gamma}-H{gamma}/C{beta}-H{beta} Residual Dipolar Couplings

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chun; Iwahara, Junji; Clore, G. Marius [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Laboratory of Chemical Physics (United States)], E-mail: mariusc@intra.niddk.nih.gov

    2005-10-15

    An isotope labeling scheme is described in which specific protonation of methine and methyl protons of leucine and valine is obtained on a {sup 15}N/{sup 13}C labeled background with uniform deuteration of all other non-exchangeable protons. The presence of a protonated methine group has little effect on the favorable relaxation properties of the methyl protons of Leu and Val. This labeling scheme permits the rotameric state of leucine side-chains to be readily determined by simple inspection of the pattern of H{gamma}(i)-H{sub N}(i) and H{gamma}(i)-H{sub N}(i+1) NOEs in a 3D {sup 15}N-separated NOE spectrum free of complications arising from spectral overlap and spin-diffusion. In addition, one-bond residual dipolar couplings for the methine {sup 13}C-{sup 1}H bond vectors of Leu and Val can be accurately determined from an intensity J-modulated constant-time HCCH-COSY experiment and used to accurately orient the side-chains of Leu and Val. Incorporation of these data into structure refinement improves the accuracy with which the conformations of Leu and Val side-chains can be established. This is important to ensure optimal packing both within the protein core and at intermolecular interfaces. The impact of the method on protein structure determination is illustrated by application to enzyme IIA{sup Chitobiose}, a 34 kDa homotrimeric phosphotransferase protein.

  2. Cluster Observations of Multiple Dipolarization Fronts

    Science.gov (United States)

    Hwang, Kyoung-Joo; Goldstein, Melvyn L.; Lee, Ensang; Pickett, Jolene S.

    2011-01-01

    We present Cluster observations of a series of dipolarization fronts (DF 1 to 6) at the central current sheet in Earth's magnetotail. The velocities of fast earthward flow following behind each DF 1-3, are comparable to the Alfven velocity, indicating that the flow bursts might have been generated by bursty reconnection that occurred tailward of the spacecraft. Based on multi-spacecraft timing analysis, DF normals are found to propagate mainly earthward at $160-335$ km/s with a thickness of 900-1500 km, which corresponds to the ion inertial length or gyroradius scale. Each DF is followed by significant fluctuations in the $x$ and $y$ components of the magnetic field whose peaks are found 1-2 minutes after the DF passage. These $(B_{x},B_{y} )$-fluctuations propagate dawnward (mainly) and earthward. Strongly enhanced field-aligned beams are observed coincidently with $(B_{x},B_{y})$ fluctuations, while an enhancement of cross-tail currents is associated with the DFs. From the observed pressure imbalance and flux-tube entropy changes between the two regions separated by the DF, we speculate that interchange instability destabilizes the DFs and causes the deformation of the mid-tail magnetic topology. This process generates significant field-aligned currents, and might power the auroral brightening in the ionosphere. However, this event is neither associated with the main substorm auroral breakup nor the poleward expansion, which might indicate that the observed multiple DFs have been dissipated before they reach the inner plasma sheet boundary.

  3. Outcomes of couples with infidelity in a community-based sample of couple therapy.

    Science.gov (United States)

    Atkins, David C; Marín, Rebeca A; Lo, Tracy T Y; Klann, Notker; Hahlweg, Kurt

    2010-04-01

    Infidelity is an often cited problem for couples seeking therapy, but the research literature to date is very limited on couple therapy outcomes when infidelity is a problem. The current study is a secondary analysis of a community-based sample of couple therapy in Germany and Austria. Outcomes for 145 couples who reported infidelity as a problem in their relationship were compared with 385 couples who sought therapy for other reasons. Analyses based on hierarchical linear modeling revealed that infidelity couples were significantly more distressed and reported more depressive symptoms at the start of therapy but continued improving through the end of therapy and to 6 months posttherapy. At the follow-up assessment, infidelity couples were not statistically distinguishable from non-infidelity couples, replicating previous research. Sexual dissatisfaction did not depend on infidelity status. Although there was substantial missing data, sensitivity analyses suggested that the primary findings were not due to missing data. The current findings based on a large community sample replicated previous work from an efficacy trial and show generally optimistic results for couples in which there has been an affair. 2010 APA, all rights reserved

  4. Heterogeneous dipolar theory of the exponential pile

    International Nuclear Information System (INIS)

    Mastrangelo, P.V.

    1981-01-01

    We present a heterogeneous theory of the exponential pile, closely related to NORDHEIM-SCALETTAR's. It is well adapted to lattice whose pitch is relatively large (D-2O, grahpite) and the dimensions of whose channels are not negligible. The anisotropy of neutron diffusion is taken into account by the introduction of dipolar parameters. We express the contribution of each channel to the total flux in the moderator by means of multipolar coefficients. In order to be able to apply conditions of continuity between the flux and their derivatives, on the side of the moderator, we develop in a Fourier series the fluxes found at the periphery of each channel. Using Wronski's relations of Bessel's functions, we express the multipolar coefficients of the surfaces of each channel, on the side of the moderator, by means of the harmonics of each flux and their derivatives. We retain only monopolar (A 0 sub(g)) and dipolar (A 1 sub(g)) coefficients; those of a higher order are ignored. We deduce from these coefficients the systems of homogeneous equations of the exponential pile with monopoles on their own and monopoles plus dipoles. It should be noted that the systems of homogeneous equations of the critical pile are contained in those of the exponential pile. In another article, we develop the calculation of monopolar and dipolar heterogeneous parameters. (orig.)

  5. Do Couple-Based Interventions Make a Difference for Couples Affected by Cancer?: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Regan Tim W

    2012-07-01

    Full Text Available Abstract Background With the growing recognition that patients and partners react to a cancer diagnosis as an interdependent system and increasing evidence that psychosocial interventions can be beneficial to both patients and partners, there has been a recent increase in the attention given to interventions that target couples. The aim of this systematic review was to identify existing couple-based interventions for patients with cancer and their partners and explore the efficacy of these interventions (including whether there is added value to target the couple versus individuals, the content and delivery of couple-based interventions, and to identify the key elements of couple-based interventions that promote improvement in adjustment to cancer diagnosis. Method A systematic review of the cancer literature was performed to identify experimental and quasi-experimental couple-based interventions published between 1990 and 2011. To be considered for this review, studies had to test the efficacy of a psychosocial intervention for couples affected by cancer. Studies were excluded if they were published in a language other than English or French, focused on pharmacological, exercise, or dietary components combined with psychosocial components, or did not assess the impact of the intervention on psychological distress (e.g., depression, anxiety or quality of life. Data were extracted using a standardised data collection form, and were analysed independently by three reviewers. Results Of the 709 articles screened, 23 were included in this review. Couple-based interventions were most efficacious in improving couple communication, psychological distress, and relationship functioning. Interventions had a limited impact on physical distress and social adjustment. Most interventions focused on improving communication and increasing understanding of the cancer diagnosis within couples. Interventions were most often delivered by masters-level nurses or

  6. An initial boundary value problem for modeling a piezoelectric dipolar body

    Science.gov (United States)

    Marin, Marin; Öchsner, Andreas

    2018-03-01

    This study deals with the first initial boundary value problem in elasticity of piezoelectric dipolar bodies. We consider the most general case of an anisotropic and inhomogeneous elastic body having a dipolar structure. For two different types of restrictions imposed on the problem data, we prove two results regarding the uniqueness of solution, by using a different but accessible method. Then, the mixed problem is transformed in a temporally evolutionary equation on a Hilbert space, conveniently constructed based on the problem data. With the help of a known result from the theory of semigroups of operators, the existence and uniqueness of the weak solution for this equation are proved.

  7. On nonlinear dynamics of a dipolar exciton BEC in two-layer graphene

    International Nuclear Information System (INIS)

    Berman, O.L.; Kezerashvili, R.Ya.; Kolmakov, G.V.

    2012-01-01

    The nonlinear dynamics of a Bose–Einstein condensate (BEC) of dipolar excitons in two-layer graphene is studied. It is demonstrated that a steady turbulent state is formed in this system. A comparison between the dynamics of the exciton BEC in two-layer graphene and those in GaAs/AlGaAs coupled quantum wells shows that turbulence is a general effect in a BEC.

  8. Effect of Couple Therapy Based on the Choice Theory on Social Commitment of Couples

    Directory of Open Access Journals (Sweden)

    Hossein Abbasi

    2017-09-01

    Full Text Available Background and Objective: Commitment to spouse, marriage, and family is one of the most important factors ensuring the continuity of marriage and strength of family bonds that has attracted considerable attention in the contemporary family and marriage studies. In this study, we sought to determine the effect of couple therapy based on the choice theory on the social commitment of couples. Materials and Methods: This was a quasi-experimental study with pretest-posttest design and a control group that was performed among volunteer couples visiting Isfahan Counseling and Psychology Centers in Isfahan, Iran, during 2015. The subjects consisted of 32 incompatible couples who were selected through convenience sampling and were randomly assigned into experimental (16 couples and control (16 couples groups. Then, the experimental group received nine sessions of group couple therapy during three months on family life skills based on choice theory. It is worth mentioning that the dependent variable was the social commitment of couples evaluated by the dimensions of commitment inventory of Adams and Jones (1997. The collected data were analyzed by multivariate analysis of covariance in SPSS, version 20. Results: At the post-test stage, couple therapy based on choice theory significantly enhanced social commitment in the experimental group compared to the control group (P<0.001. Conclusion: According to the findings of this study, couple therapy based on the choice theory is an effective strategy in promoting commitment and loyalty to spouse, marriage, and family and can decrease and prevent family-related problems and threats such as divorce and marital infidelity.

  9. Existence of solitary waves in dipolar quantum gases

    KAUST Repository

    Antonelli, Paolo; Sparber, Christof

    2011-01-01

    We study a nonlinear Schrdinger equation arising in the mean field description of dipolar quantum gases. Under the assumption of sufficiently strong dipolar interactions, the existence of standing waves, and hence solitons, is proved together with some of their properties. This gives a rigorous argument for the possible existence of solitary waves in BoseEinstein condensates, which originate solely due to the dipolar interaction between the particles. © 2010 Elsevier B.V. All rights reserved.

  10. Existence of solitary waves in dipolar quantum gases

    KAUST Repository

    Antonelli, Paolo

    2011-02-01

    We study a nonlinear Schrdinger equation arising in the mean field description of dipolar quantum gases. Under the assumption of sufficiently strong dipolar interactions, the existence of standing waves, and hence solitons, is proved together with some of their properties. This gives a rigorous argument for the possible existence of solitary waves in BoseEinstein condensates, which originate solely due to the dipolar interaction between the particles. © 2010 Elsevier B.V. All rights reserved.

  11. Quantum simulation and quantum information processing with molecular dipolar crystals

    International Nuclear Information System (INIS)

    Ortner, M.

    2011-01-01

    In this thesis interactions between dipolar crystals and neutral atoms or separated molecules have been investigated. They were motivated to realize new kinds of lattice models in mixtures of atoms and polar molecules where an MDC functions as an underlying periodic lattice structure for the second species. Such models bring out the peculiar features of MDC's, that include a controllable, potentially sub-optical wavelength periodicity and strong particle phonon interactions. Only stable collisional configurations have been investigated, excluding chemical reactions between the substituents, and crystal distortions beyond the scope of perturbation theory. The system was treated in the polaron picture where particles of the second species are dressed by surrounding crystal phonons. To describe the competition between coherent and incoherent dynamics of the polarons, a master equation in the Brownian motion limit was used with phonons treated as a thermal heat bath. It was shown analytically that in a wide range of realistic parameters the corrections to the coherent time evolution are small, and that the dynamics of the dressed particles can be described by an effective extended Hubbard model with controllable system parameters. The last chapter of this thesis contains a proposal for QIP with cold polar molecules that, in contrast to previous works, uses an MDC as a quantum register. It was motivated by the unique features of dipolar molecules and to exploit the peculiar physical conditions in dipolar crystals. In this proposal the molecular dipole moments were tailored by non-local fields to include a small, switchable, state-dependent dipole moment in addition to the large internal state independent moment that stabilizes the crystal. It was shown analytically that a controllable, non-trivial phonon-mediated interaction can be generated that exceeds non-trivial, direct dipole-dipole couplings. The addressability problem due to high crystal densities was overcome by

  12. Using the phase shift to asymptotically characterize the dipolar mixed modes in post-main-sequence stars

    DEFF Research Database (Denmark)

    Jiang, C.; Christensen-Dalsgaard, J.; Cunha, M.

    2018-01-01

    from the eigenvalue condition for mixed modes as a tool to characterize dipolar mixed modes from the theoretical as well as the practical point of view. Unlike the coupling strength, whose variation in a given star is very small over the relevant frequency range, the phase shifts vary significantly...

  13. Seniority-based coupled cluster theory

    International Nuclear Information System (INIS)

    Henderson, Thomas M.; Scuseria, Gustavo E.; Bulik, Ireneusz W.; Stein, Tamar

    2014-01-01

    Doubly occupied configuration interaction (DOCI) with optimized orbitals often accurately describes strong correlations while working in a Hilbert space much smaller than that needed for full configuration interaction. However, the scaling of such calculations remains combinatorial with system size. Pair coupled cluster doubles (pCCD) is very successful in reproducing DOCI energetically, but can do so with low polynomial scaling (N 3 , disregarding the two-electron integral transformation from atomic to molecular orbitals). We show here several examples illustrating the success of pCCD in reproducing both the DOCI energy and wave function and show how this success frequently comes about. What DOCI and pCCD lack are an effective treatment of dynamic correlations, which we here add by including higher-seniority cluster amplitudes which are excluded from pCCD. This frozen pair coupled cluster approach is comparable in cost to traditional closed-shell coupled cluster methods with results that are competitive for weakly correlated systems and often superior for the description of strongly correlated systems

  14. Ultracold chromium: a dipolar quantum gas

    International Nuclear Information System (INIS)

    Pfau, T.; Stuhler, J.; Griesmaier, A.; Fattori, M.; Koch, T.

    2005-01-01

    We report on our recent achievement of a Bose-Einstein condensate in a gas of chromium atoms. Peculiar electronic and magnetic properties of chromium require the implementation of novel cooling strategies. We observe up to ∼ 10 5 condensed 52 Cr atoms after forced evaporation within a crossed optical dipole trap. Due to its large magnetic moment (6μ B ), the dipole-dipole interaction strength in chromium is comparable with the one of the van der Waals interaction. We prove the anisotropic nature of the dipolar interaction by releasing the condensate from a cigar shaped trap and observe, in time of flight measurements, the change of the aspect-ratio for different in-trap orientations of the atomic dipoles. We also report on the recent observation of 14 Feshbach resonances in elastic collisions between polarized ultra-cold 52 Cr atoms. This is the first Ballistic expansion of a dipolar quantum gas: The anisotropic interaction leads to a different expansion dynamics for the case of the magnetic dipoles aligned with the symmetry axis of the cigar shaped trap as compared with the dipoles oriented perpendicular to the axis of the cigar. The straight lines correspond to the theoretical expectation according to mean field theory without free parameters. observation of collisional Feshbach resonances in an atomic species with more than one valence electron. Moreover, such resonances constitute an important tool towards the realization of a purely dipolar interacting gas because they can be used to change strength and sign of the van der Waals interaction. (author)

  15. Dynamic performance analysis of diaphragm coupling base on ABAQUS

    Directory of Open Access Journals (Sweden)

    You Wen

    2017-04-01

    Full Text Available Base on the diaphragm coupling of driving system of a rotation testing machine,FEA software ABAQUS is used to simulate the force which the coupling gets when it is working,to obtain the stress and stain during the coupling with axial misalignment and degree misalignment and to find where the maximal stress is as well as its distribution.Then the nature frequency of the coupling is calculated by use of finite element software and rotor dynamics and compared with the date of misalignment and maximum speed from the manufacture,which verifies the correctness of the model and the reliability of the calculation method.

  16. Cognitive radio resource allocation based on coupled chaotic genetic algorithm

    International Nuclear Information System (INIS)

    Zu Yun-Xiao; Zhou Jie; Zeng Chang-Chang

    2010-01-01

    A coupled chaotic genetic algorithm for cognitive radio resource allocation which is based on genetic algorithm and coupled Logistic map is proposed. A fitness function for cognitive radio resource allocation is provided. Simulations are conducted for cognitive radio resource allocation by using the coupled chaotic genetic algorithm, simple genetic algorithm and dynamic allocation algorithm respectively. The simulation results show that, compared with simple genetic and dynamic allocation algorithm, coupled chaotic genetic algorithm reduces the total transmission power and bit error rate in cognitive radio system, and has faster convergence speed

  17. Non-dipolar gauge links for transverse-momentum-dependent pion wave functions

    International Nuclear Information System (INIS)

    Wang, Y.M.

    2016-01-01

    I discuss the factorization-compatible definitions of transverse-momentum-dependent (TMD) pion wave functions which are fundamental theory inputs entering QCD factorization formulae for many hard exclusive processes. I will first demonstrate that the soft subtraction factor introduced to remove both rapidity and pinch singularities can be greatly reduced by making the maximal use of the freedom to construct the Wilson-line paths when defining the TMD wave functions. I will then turn to show that the newly proposed TMD definition with non-dipolar Wilson lines is equivalent to the one with dipolar gauge links and with a complicated soft function, to all orders of the perturbative expansion in the strong coupling, as far as the infrared behavior is concerned. (author)

  18. Mechanism and regioselectivity of 1,3-dipolar cycloaddition ...

    Indian Academy of Sciences (India)

    1,3-Dipolar cycloaddition; sulphur-centred 1,3-dipoles; regioselectivity; DFT reactivity indices;. FMO theory. 1. Introduction. Five-membered heterocyclic compounds can be gene- rated by addition of a 1,3-dipole to a dipolarophile under a 1,3-dipolar cycloaddition (1,3-DC) reaction which is well known as pericyclic reaction.

  19. Critical Time Crystals in Dipolar Systems.

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D; Abanin, Dmitry A

    2017-07-07

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017)NATUAS0028-083610.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

  20. Cluster and Double Star observations of dipolarization

    Directory of Open Access Journals (Sweden)

    R. Nakamura

    2005-11-01

    Full Text Available We studied two types of dipolarization events with different IMF conditions when Cluster and Double Star (TC-1 were located in the same local time sector: 7 August 2004, 18:00-24:00 UT, during a disturbed southward/northward IMF interval, and 14 August 2004, 21:00-24:00 UT, when the IMF was stably northward. Cluster observed dipolarization as well as fast flows during both intervals, but this was not the case for TC-1. For both events the satellites crossed near the conjugate location of the MIRACLE stations. By using multi-point analysis techniques, the direction/speed of the propagation is determined using Cluster and is then compared with the disturbances at TC-1 to discuss its spatial/temporal scale. The propagation direction of the BZ disturbance at Cluster was mainly dawnward with a tailward component for 7 August and with a significant Earthward component for 14 August associated with fast flows. We suggest that the role of the midtail fast flows can be quite different in the dissipation process depending on the condition of the IMF and resultant configuration of the tail.

  1. Perturbation theories for the dipolar fluids

    International Nuclear Information System (INIS)

    Lee, L.L.; Chung, T.H.

    1983-01-01

    We derive here four different perturbation equations for the calculation of the angular pair correlation functions of dipolar fluids; namely, the first order y-expansion, the modified Percus--Yevik (MPY) expansion, the modified hypernetted chain (MHNC) expansion, and the modified linearized hypernetted chain (MLHNC) equation. Both the method of the functional expansion and the method of the cluster integrals are utilized. Comparison with other perturbation theories (e.g., the Melnyk--Smith equation) is made. While none of the theories is exact, as shown by the cluster diagrams, the MLHNC and the MHNC contain more diagrams than, say, the MPY and y-expansion. The y-expansion equation can be improved by including the correction terms to the Kirkwood superposition approximation for the triplet correlation function. For example, the inclusion of the correction term rho∫d4h(14)h(24)h(34) in a formula given by Henderson, is shown to improve substantially the y-expansion equation. We examine the performance of two of the theories: the y-expansion and the MLHNC equation for a Stockmayer (dipolar) fluid with a reduced dipole moment μ/sup asterisk2/ [ = μ 2 /(epsilonsigma 3 )] = 1.0. Comparison with Monte Carlo simulation results of Adams et al. and with other theories (e.g., the QHNC equation) shows that our results are reasonable. Further improvements of the equations are also pointed out

  2. New Developments in Spin Labels for Pulsed Dipolar EPR

    Directory of Open Access Journals (Sweden)

    Alistair J. Fielding

    2014-10-01

    Full Text Available Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR techniques allow small magnetic couplings to be measured (e.g., <50 MHz providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.

  3. Residual dipolar couplings: are multiple independent alignments always possible?

    International Nuclear Information System (INIS)

    Higman, Victoria A.; Boyd, Jonathan; Smith, Lorna J.; Redfield, Christina

    2011-01-01

    RDCs for the 14 kDa protein hen egg-white lysozyme (HEWL) have been measured in eight different alignment media. The elongated shape and strongly positively charged surface of HEWL appear to limit the protein to four main alignment orientations. Furthermore, low levels of alignment and the protein’s interaction with some alignment media increases the experimental error. Together with heterogeneity across the alignment media arising from constraints on temperature, pH and ionic strength for some alignment media, these data are suitable for structure refinement, but not the extraction of dynamic parameters. For an analysis of protein dynamics the data must be obtained with very low errors in at least three or five independent alignment media (depending on the method used) and so far, such data have only been reported for three small 6–8 kDa proteins with identical folds: ubiquitin, GB1 and GB3. Our results suggest that HEWL is likely to be representative of many other medium to large sized proteins commonly studied by solution NMR. Comparisons with over 60 high-resolution crystal structures of HEWL reveal that the highest resolution structures are not necessarily always the best models for the protein structure in solution.

  4. The Plasma Sheet as Natural Symmetry Plane for Dipolarization Fronts in the Earth's Magnetotail

    Science.gov (United States)

    Frühauff, D.; Glassmeier, K.-H.

    2017-11-01

    In this work, observations of multispacecraft mission Time History of Events and Macroscale Interactions during Substorms are used for statistical investigation of dipolarization fronts in the near-Earth plasma sheet of the magnetotail. Using very stringent criteria, 460 events are detected in almost 10 years of mission data. Minimum variance analysis is used to determine the normal directions of the phase fronts, providing evidence for the existence of a natural symmetry of these phenomena, given by the neutral sheet of the magnetotail. This finding enables the definition of a local coordinate system based on the Tsyganenko model, reflecting the intrinsic orientation of the neutral sheet and, therefore, the dipolarization fronts. In this way, the comparison of events with very different background conditions is improved. Through this study, the statistical results of Liu, Angelopoulos, Runov, et al. (2013) are both confirmed and extended. In a case study, the knowledge of this plane of symmetry helps to explain the concave curvature of dipolarization fronts in the XZ plane through phase propagation speeds of magnetoacoustic waves. A second case study is presented to determine the central current system of a passing dipolarization front through a constellation of three spacecraft. With this information, a statistical analysis of spacecraft observations above and below the neutral sheet is used to provide further evidence for the neutral sheet as the symmetry plane and the central current system. Furthermore, it is shown that the signatures of dipolarization fronts are under certain conditions closely related to that of flux ropes, indicating a possible relationship between these two transient phenomena.

  5. Dipolar vortex structures in magnetized rotating plasma

    International Nuclear Information System (INIS)

    Liu Jixing

    1990-01-01

    Dipolar solitary vortices of both electrostatic and electromagnetic character in low-β, in homogeneous rotating plasma confined in a constant external magnetic field were systematically presented. The main stimulus to this investigation is the expectation to apply this coherent structure as a candidate constituent of plasma turbulance to understand the anomalous transport phenomena in confined plasma. The electrostatic vortices have similar structure and properties as the Rossby vortices in rotating fluids, the electromagnetic vortices obtained here have no analogy in hydrodynamics and hence are intrinsic to magnetized plasma. It is valuably remarked that the intrinsic electromagnetic vortices presented here have no discontinuity of perturbed magnetic field δB and parallel current j(parallel) on the border of vortex core. The existence region of the new type of vortex is found much narrower than the Rossby type one. (M.T.)

  6. Characterizing Ion Flows Across a Dipolarization Front

    Science.gov (United States)

    Arnold, H.; Drake, J. F.; Swisdak, M.

    2017-12-01

    In light of the Magnetospheric Multiscale Mission (MMS) moving to study predominately symmetric magnetic reconnection in the Earth's magnetotail, it is of interest to investigate various methods for determining the relative location of the satellites with respect to the x line or a dipolarization front. We use a 2.5 dimensional PIC simulation to explore the dependence of various characteristics of a front, or flux bundle, on the width of the front in the dawn-dusk direction. In particular, we characterize the ion flow in the x-GSM direction across the front. We find a linear relationship between the width of a front, w, and the maximum velocity of the ion flow in the x-GSM direction, Vxi, for small widths: Vxi/VA=w/di*1/2*(mVA2)/Ti*Bz/Bxwhere m, VA, di, Ti, Bz, and Bx are the ion mass, upstream Alfven speed, ion inertial length, ion temperature, and magnetic fields in the z-GSM and x-GSM directions respectively. However, once the width reaches around 5 di, the relationship gradually approaches the well-known theoretical limit for ion flows, the upstream Alfven speed. Furthermore, we note that there is a reversal in the Hall magnetic field near the current sheet on the positive y-GSM side of the front. This reversal is most likely due to conservation of momentum in the y-GSM direction as the ions accelerate towards the x-GSM direction. This indicates that while the ions are primarily energized in the x-GSM direction by the front, they transfer energy to the electromagnetic fields in the y-GSM direction. The former energy transfer is greater than the latter, but the reversal of the Hall magnetic field drags the frozen-in electrons along with it outside of the front. These simulations should better able researchers to determine the relative location of a satellite crossing a dipolarization front.

  7. Luttinger hydrodynamics of confined one-dimensional Bose gases with dipolar interactions

    International Nuclear Information System (INIS)

    Citro, R; Palo, S De; Orignac, E; Pedri, P; Chiofalo, M-L

    2008-01-01

    Ultracold bosonic and fermionic quantum gases confined to quasi-one-dimensional (1D) geometry are promising candidates for probing fundamental concepts of Luttinger liquid (LL) physics. They can also be exploited for devising applications in quantum information processing and precision measurements. Here, we focus on 1D dipolar Bose gases, where evidence of super-strong coupling behavior has been demonstrated by analyzing the low-energy static and dynamical structures of the fluid at zero temperature by a combined reptation quantum Monte Carlo (RQMC) and bosonization approach. Fingerprints of LL behavior emerge in the whole crossover from the already strongly interacting Tonks-Girardeau at low density to a dipolar density wave regime at high density. We have also shown that a LL framework can be effectively set up and utilized to describe this strongly correlated crossover physics in the case of confined 1D geometries after using the results for the homogeneous system in LL hydrodynamic equations within a local density approximation. This leads to the prediction of observable quantities such as the frequencies of the collective modes of the trapped dipolar gas under the more realistic conditions that could be found in ongoing experiments. The present paper provides a description of the theoretical framework in which the above results have been worked out, making available all the detailed derivations of the hydrodynamic Luttinger equations for the inhomogeneous trapped gas and of the correlation functions for the homogeneous system

  8. Management of the infertile couple: an evidence-based protocol

    Directory of Open Access Journals (Sweden)

    Kamel Remah M

    2010-03-01

    Full Text Available Abstract Background Infertility is defined as inability of a couple to conceive naturally after one year of regular unprotected sexual intercourse. It remains a major clinical and social problem, affecting perhaps one couple in six. Evaluation usually starts after 12 months; however it may be indicated earlier. The most common causes of infertility are: male factor such as sperm abnormalities, female factor such as ovulation dysfunction and tubal pathology, combined male and female factors and unexplained infertility. Objectives The aim of this study is to provide the healthcare professionals an evidence-based management protocol for infertile couples away from medical information overload. Methods A comprehensive review where the literature was searched for "Management of infertility and/or infertile couples" at library website of University of Bristol (MetaLib by using a cross-search of different medical databases besides the relevant printed medical journals and periodicals. Guidelines and recommendations were retrieved from the best evidence reviews such as that from the American College of Obstetricians and Gynaecologists (ACOG, American Society for Reproductive Medicine (ASRM, Canadian Fertility and Andrology Society (CFAS, and Royal College of Obstetricians and Gynaecologists (RCOG. Results A simple guide for the clinicians to manage the infertile couples. Conclusions The study deploys a new strategy to translate the research findings and evidence-base recommendations into a simplified focused guide to be applied on routine daily practice. It is an approach to disseminate the recommended medical care for infertile couple to the practicing clinicians.

  9. Phase transitions in random uniaxial systems with dipolar interactions

    International Nuclear Information System (INIS)

    Schuster, H.G.

    1977-01-01

    The critical behaviour of random uniaxial ferromagnetic (ferroelectric) systems with both short range and long range dipolar interactions is investigated, using the field theoretic renormalization method of Brezin et al. for the free energy above and below transition point Tsub(c). The randomness is due to externally introduced fluctuations in the short range interactions (quenched case) or (and) magneto-elastic coupling to the lattice (annealed case). Strong deviations in the critical behaviour with respect to the pure systems are found. In the quenched case, e.g., the specific heat C and the coefficient f 2 (of M 3 in the equation of state, where M is the magnetization) change from C proportional to abs ln abs t abs abssup(1/3), f 2 proportional to abs ln abs t abs abs sup(1/3), f 2 proportional to abs ln abs t abs abs -1 in the pure system to C = A+- + C+-exp[-4√ 3 106 abs ln abs t abs abs], f 2 proportional to abs ln abs t abs abs sup(-1/2) (where t = (T-Tsub(c)) / Tsub(c) is the reduced temperature and A+-, C+- are constants) in the random situation. (orig.) [de

  10. Focal mechanism of seismic events with a dipolar component

    Directory of Open Access Journals (Sweden)

    R. Console

    1995-06-01

    Full Text Available In this paper we model the geometry of a seismic source as a dislocation occurring on an elemental flat fault in an arbitrary direction with respect to the fault plane. This implies the use of a fourth parameter in addition to the three usual ones describing a simple double couple mechanism. We applied the radiation pattern obtained from the theory to a computer code written for the inversion of the observation data (amplitudes and polarities of the first onsets recorded by a network of stations. It allows the determination of the fault mechanism gener- alized in the above mentioned way. The computer code was verified on synthetic data and then applied to real data recorded by the seismic network operated by the Ente Nazionale per l'Energia Elettrica (ENEL, monitoring the geothermal field of Larderello. The experimental data show that for some events the source mechanism exhibits a significant dipolar component. However, due to the high standard deviation of the amplitude data, F-test applied to the results of the analysis shows that only for two events the confidence level for the general- ized model exceeds 90%.

  11. The quantum coherence of disordered dipolar bosonic gas

    International Nuclear Information System (INIS)

    Wang Jiguo; Zhang Aixia; Tang Rongan; Gao Jimin; Xue Jukui

    2013-01-01

    We investigate the coherence of correlated dipolar gas in the presence of disorder within a three-site Bose–Hubbard model. We show that the interplay between the on-site interaction, the inter-site dipole–dipole interactions (DDI) and the disorder exhibits new and interesting coherence characters that cannot take place in a non-dipolar system. The ratio between the on-site interaction and DDI plays a dominant role in the phase coherence. The resonance character of the coherence against both disorder and interactions emerges. DDI can enhance the coherence at certain values of the disorder and on-site interaction. In the coherence region, the enhancement of the coherence by disorder in a dipolar system is more significant than that in a non-dipolar system. In particular, the on-site interaction and DDI together can enhance the coherence even in the clean dipolar system (i.e. a dipolar system without disorder). However, without the on-site interaction, disorder, DDI or both together suppress the coherence. Furthermore, the relationship between the coherence and the energy gap and the compressibility of the system is also discussed. (paper)

  12. Dipolar oscillations in a quantum degenerate Fermi-Bose atomic mixture

    International Nuclear Information System (INIS)

    Ferlaino, F; Brecha, R J; Hannaford, P; Riboli, F; Roati, G; Modugno, G; Inguscio, M

    2003-01-01

    We study the dynamics of coupled dipolar oscillations in a Fermi-Bose mixture of 40 K and 87 Rb atoms. This low-energy collective mode is strongly affected by the interspecies interactions. Measurements are performed in the classical and quantum degenerate regimes and reveal the crucial role of the statistical properties of the mixture. At the onset of quantum degeneracy, we investigate the role of Pauli blocking and superfluidity for K and Rb atoms, respectively, resulting in a change in the collisional interactions

  13. Microcomputer based test system for charge coupled devices

    International Nuclear Information System (INIS)

    Sidman, S.

    1981-02-01

    A microcomputer based system for testing analog charge coupled integrated circuits has been developed. It measures device performance for three parameters: dynamic range, baseline shift due to leakage current, and transfer efficiency. A companion board tester has also been developed. The software consists of a collection of BASIC and assembly language routines developed on the test system microcomputer

  14. Dipolar particles in a double-trap confinement: Response to tilting the dipolar orientation

    Science.gov (United States)

    Bjerlin, J.; Bengtsson, J.; Deuretzbacher, F.; Kristinsdóttir, L. H.; Reimann, S. M.

    2018-02-01

    We analyze the microscopic few-body properties of dipolar particles confined in two parallel quasi-one-dimensional harmonic traps. In particular, we show that an adiabatic rotation of the dipole orientation about the trap axes can drive an initially nonlocalized few-fermion state into a localized state with strong intertrap pairing. With an instant, nonadiabatic rotation, however, localization is inhibited and a highly excited state is reached. This state may be interpreted as the few-body analog of a super-Tonks-Girardeau state, known from one-dimensional systems with contact interactions.

  15. Dipolar-induced interplay between inter-level physics and macroscopic phase transitions in triple-well potentials

    International Nuclear Information System (INIS)

    Zhang Aixia; Xue Jukui

    2012-01-01

    We propose a scheme to reveal the interplay between dipole–dipole interaction (DDI), inter-level coupling and macroscopic phase transitions in dipolar condensates. By considering a macroscopic sample of dipolar bosons in triple-well potentials, DDI-induced coupling between the inter-level physics and the macroscopic phase transitions is presented. When the DDI exceeds certain thresholds, the degeneracy of the two lowest energy levels and the excitation of new eigenstates occur, respectively. Interestingly, these thresholds give the boundaries of various quantum phase transitions. That is, the quantum phase transitions are the consequence of the levels' degeneracy and the new eigenstates' excitation. Furthermore, DDI-induced long-range macroscopic Josephson oscillations are observed and long-range coherent quantum transportation is achieved. Our results give clear proof of the interplay between the multi-level physics and quantum phase transitions, and also provide a way for designing the long-range coherent quantum transportation. (paper)

  16. Couplings

    Science.gov (United States)

    Stošić, Dušan; Auroux, Aline

    Basic principles of calorimetry coupled with other techniques are introduced. These methods are used in heterogeneous catalysis for characterization of acidic, basic and red-ox properties of solid catalysts. Estimation of these features is achieved by monitoring the interaction of various probe molecules with the surface of such materials. Overview of gas phase, as well as liquid phase techniques is given. Special attention is devoted to coupled calorimetry-volumetry method. Furthermore, the influence of different experimental parameters on the results of these techniques is discussed, since it is known that they can significantly influence the evaluation of catalytic properties of investigated materials.

  17. Flow-based market coupling. Stepping stone towards nodal pricing?

    International Nuclear Information System (INIS)

    Van der Welle, A.J.

    2012-07-01

    For achieving one internal energy market for electricity by 2014, market coupling is deployed to integrate national markets into regional markets and ultimately one European electricity market. The extent to which markets can be coupled depends on the available transmission capacities between countries. Since interconnections are congested from time to time, congestion management methods are deployed to divide the scarce available transmission capacities over market participants. For further optimization of the use of available transmission capacities while maintaining current security of supply levels, flow-based market coupling (FBMC) will be implemented in the CWE region by 2013. Although this is an important step forward, important hurdles for efficient congestion management remain. Hence, flow based market coupling is compared to nodal pricing, which is often considered as the most optimal solution from theoretical perspective. In the context of decarbonised power systems it is concluded that advantages of nodal pricing are likely to exceed its disadvantages, warranting further development of FBMC in the direction of nodal pricing.

  18. Structure and magnetic exchange coupling of iron based trilayers

    International Nuclear Information System (INIS)

    Mendus, T.

    1998-12-01

    A study of the structural and magnetic properties of Fe based magnetic trilayers is presented. Sample preparation conditions were altered to achieve the best growth conditions and their effect on the magnetic properties determined. Structural information was obtained from RHEED, AES, STM and MEIS; this is believed to be the first time that MEIS has been used to look at this sort of sample. Magnetic characterisation was determined by MOKE with particular interest paid to the biquadratic coupling. The determination of magnetic coupling as a function of sample morphology was studied oil a series of Fe/Cr/Fe samples. Fe/Au/Fe samples oil MgO substrates were also prepared to facilitate MEIS studies. Results indicate that tile fluctuation model best describes tile observed biquadratic coupling in Fe/Cr/Fe trilayers and that the presence of clean, sharp interfaces is required. Annealing and growth at elevated temperature cause interdiffusion at the interfaces, weakening the biquadratic coupling. MEIS structural data from MgO/Fe/Au/Fe samples shows that tile layer structure is dependent oil thickness. There is an apparent reorganisation of tile Au interlayer between a 'bcc'-Iike phase towards tile bulk fcc phase as the layer thickness increases. MEIS is shown to be a very sensitive probe of the crystalline quality and is a powerful probe for the determination of postdeposition sample morphology. Results from an EC collaboration investigating Co/Cr/Co trilayers are also presented. They showed that interlayer coupling and anisotropy of the samples were very sensitive to the preparation conditions. A decrease in the coupling strength is found for sample growth under non-ideal conditions (growth in an applied field, growth at an angle and delays between layer growth). (author)

  19. Jet Dipolarity: Top Tagging with Color Flow

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Jankowiak, Martin; /SLAC /Stanford U., Phys. Dept.; Wacker, Jay G.; /SLAC

    2011-08-12

    A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high p{sub T}. The impressive resolution of the ATLAS and CMS detectors means that a typical QCD jet at the LHC deposits energy in {Omicron}(10-100) calorimeter cells. Such fine-grained calorimetry allows for jets to be studied in much greater detail than previously, with sophisticated versions of current techniques making it possible to measure more than just the bulk properties of jets (e.g. event jet multiplicities or jet masses). One goal of the LHC is to employ these techniques to extend the amount of information available from each jet, allowing for a broader probe of the properties of QCD. The past several years have seen significant progress in developing such jet substructure techniques. A number of general purpose tools have been developed, including: (i) top-tagging algorithms designed for use at both lower and higher p{sub T} as well as (ii) jet grooming techniques such as filtering, pruning, and trimming, which are designed to improve jet mass resolution. Jet substructure techniques have also been studied in the context of specific particle searches, where they have been shown to substantially extend the reach of traditional search techniques in a wide variety of scenarios, including for example boosted Higgses, neutral spin-one resonances, searches for supersymmetry, and many others. Despite these many successes, however, there is every reason to expect that there remains room for refinement of jet substructure techniques.

  20. Quasi-parallel whistler mode waves observed by THEMIS during near-earth dipolarizations

    Science.gov (United States)

    Le Contel, O.; Roux, A.; Jacquey, C.; Robert, P.; Berthomier, M.; Chust, T.; Grison, B.; Angelopoulos, V.; Sibeck, D.; Chaston, C. C.; Cully, C. M.; Ergun, B.; Glassmeier, K.-H.; Auster, U.; McFadden, J.; Carlson, C.; Larson, D.; Bonnell, J. W.; Mende, S.; Russell, C. T.; Donovan, E.; Mann, I.; Singer, H.

    2009-06-01

    We report on quasi-parallel whistler emissions detected by the near-earth satellites of the THEMIS mission before, during, and after local dipolarization. These emissions are associated with an electron temperature anisotropy α=T⊥e/T||e>1 consistent with the linear theory of whistler mode anisotropy instability. When the whistler mode emissions are observed the measured electron anisotropy varies inversely with β||e (the ratio of the electron parallel pressure to the magnetic pressure) as predicted by Gary and Wang (1996). Narrow band whistler emissions correspond to the small α existing before dipolarization whereas the broad band emissions correspond to large α observed during and after dipolarization. The energy in the whistler mode is leaving the current sheet and is propagating along the background magnetic field, towards the Earth. A simple time-independent description based on the Liouville's theorem indicates that the electron temperature anisotropy decreases with the distance along the magnetic field from the equator. Once this variation of α is taken into account, the linear theory predicts an equatorial origin for the whistler mode. The linear theory is also consistent with the observed bandwidth of wave emissions. Yet, the anisotropy required to be fully consistent with the observations is somewhat larger than the measured one. Although the discrepancy remains within the instrumental error bars, this could be due to time-dependent effects which have been neglected. The possible role of the whistler waves in the substorm process is discussed.

  1. Quasi-parallel whistler mode waves observed by THEMIS during near-earth dipolarizations

    Directory of Open Access Journals (Sweden)

    O. Le Contel

    2009-06-01

    Full Text Available We report on quasi-parallel whistler emissions detected by the near-earth satellites of the THEMIS mission before, during, and after local dipolarization. These emissions are associated with an electron temperature anisotropy α=T⊥e/T||e>1 consistent with the linear theory of whistler mode anisotropy instability. When the whistler mode emissions are observed the measured electron anisotropy varies inversely with β||e (the ratio of the electron parallel pressure to the magnetic pressure as predicted by Gary and Wang (1996. Narrow band whistler emissions correspond to the small α existing before dipolarization whereas the broad band emissions correspond to large α observed during and after dipolarization. The energy in the whistler mode is leaving the current sheet and is propagating along the background magnetic field, towards the Earth. A simple time-independent description based on the Liouville's theorem indicates that the electron temperature anisotropy decreases with the distance along the magnetic field from the equator. Once this variation of α is taken into account, the linear theory predicts an equatorial origin for the whistler mode. The linear theory is also consistent with the observed bandwidth of wave emissions. Yet, the anisotropy required to be fully consistent with the observations is somewhat larger than the measured one. Although the discrepancy remains within the instrumental error bars, this could be due to time-dependent effects which have been neglected. The possible role of the whistler waves in the substorm process is discussed.

  2. Phase transitions to dipolar clusters and charge density waves in high T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Saarela, M., E-mail: Mikko.Saarela@oulu.fi [Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 (Finland); Kusmartsev, F.V. [Department of Physics, Loughborough University, LE11 3TU (United Kingdom)

    2017-02-15

    We show that doping of hole charge carriers leads to formation of electric dipolar clusters in cuprates. They are created by many-body interactions between the dopant ion outside and holes inside the CuO planes. Because of the two-fold degeneracy holes in the CuO plane cluster into four-particles resonance valence bond plaquettes bound with dopant ions. Such dipoles may order into charge-density waves (CDW) or stripes or form a disordered state depending on doping and temperature. The lowest energy of the ordered system corresponds to a local anti-ferroelectric ordering. The mobility of individual disordered dipoles is very low at low temperatures and they prefer first to bind into dipole-dipole pairs. Electromagnetic radiation interacts strongly with electric dipoles and when the sample is subjected to it the mobility changes significantly. This leads to a fractal growth of dipolar clusters. The existence of electric dipoles and CDW induce two phase transitions with increasing temperature, melting of the ordered state and disappearance of the dipolar state. Ferroelectricity at low doping is a natural consequence of such dipole moments. We develop a theory based on two-level systems and dipole-dipole interaction to explain the behavior of the polarization as a function of temperature and electric field.

  3. Phase transitions to dipolar clusters and charge density waves in high T_c superconductors

    International Nuclear Information System (INIS)

    Saarela, M.; Kusmartsev, F.V.

    2017-01-01

    We show that doping of hole charge carriers leads to formation of electric dipolar clusters in cuprates. They are created by many-body interactions between the dopant ion outside and holes inside the CuO planes. Because of the two-fold degeneracy holes in the CuO plane cluster into four-particles resonance valence bond plaquettes bound with dopant ions. Such dipoles may order into charge-density waves (CDW) or stripes or form a disordered state depending on doping and temperature. The lowest energy of the ordered system corresponds to a local anti-ferroelectric ordering. The mobility of individual disordered dipoles is very low at low temperatures and they prefer first to bind into dipole-dipole pairs. Electromagnetic radiation interacts strongly with electric dipoles and when the sample is subjected to it the mobility changes significantly. This leads to a fractal growth of dipolar clusters. The existence of electric dipoles and CDW induce two phase transitions with increasing temperature, melting of the ordered state and disappearance of the dipolar state. Ferroelectricity at low doping is a natural consequence of such dipole moments. We develop a theory based on two-level systems and dipole-dipole interaction to explain the behavior of the polarization as a function of temperature and electric field.

  4. Understanding the anisotropic ion distributions within magnetotail dipolarizing flux bundles

    Science.gov (United States)

    Zhou, X.; Runov, A.; Angelopoulos, V.; Birn, J.

    2017-12-01

    Dipolarizing flux bundles (DFBs), earthward-propagating structures with enhanced northward magnetic field (Bz) component, are usually believed to carry a different plasma population from that in the ambient magnetotail plasma sheet. The ion distribution functions within the DFB, however, are recently found to be largely controlled by the ion adiabaticity parameter κ in the ambient plasma sheet outside the DFBs. According to these observations, the ambient κ values of 2-3 usually correspond to a strong perpendicular anisotropy of suprathermal ions within the DFBs, whereas for lower κ values the ions inside the DFBs become more isotropic. Here we utilize a simple, test-particle model to explore the nature of the anisotropy and its dependence on the ambient κ values. We find that the ion anisotropy originates from successive ion reflections and reentries to the DFBs, during which the ions can be consecutively accelerated in the perpendicular direction by the DFB-carried electric field. This acceleration process may be interrupted, however, when the magnetic field lines are highly curved in the ambient plasma sheet. In this case, the ion trajectories are most stochastic outside the DFB region, which makes the reflected ions less likely to return to the DFBs for another cycle of acceleration; as a consequence, the perpendicular ion anisotropy does not appear. Given that the DFB ions are a free energy source for instabilities when they are injected towards Earth, our simple model (that reproduces most observational features on the anisotropic DFB ion distributions) may shed new lights on the coupling process between the magnetotail and the inner magneosphere.

  5. Magnetization behavior of ferrofluids with cryogenically imaged dipolar chains

    International Nuclear Information System (INIS)

    Klokkenburg, M; Erne, B H; Mendelev, V; Ivanov, A O

    2008-01-01

    Theories and simulations have demonstrated that field-induced dipolar chains affect the static magnetic properties of ferrofluids. Experimental verification, however, has been complicated by the high polydispersity of the available ferrofluids, and the morphology of the dipolar chains was left to the imagination. We now present the concentration- and field-dependent magnetization of particularly well-defined ferrofluids, with a low polydispersity, three different average particle sizes, and with dipolar chains that were imaged with and without magnetic field using cryogenic transmission electron microscopy. At low concentrations, the magnetization curves obey the Langevin equation for noninteracting dipoles. Magnetization curves for the largest particles strongly deviate from the Langevin equation but quantitatively agree with a recently developed mean-field model that incorporates the field-dependent formation and alignment of flexible dipolar chains. The combination of magnetic results and in situ electron microscopy images provides original new evidence for the effect of dipolar chains on the field-dependent magnetization of ferrofluids

  6. A Coupled Simulation Architecture for Agent-Based/Geohydrological Modelling

    Science.gov (United States)

    Jaxa-Rozen, M.

    2016-12-01

    The quantitative modelling of social-ecological systems can provide useful insights into the interplay between social and environmental processes, and their impact on emergent system dynamics. However, such models should acknowledge the complexity and uncertainty of both of the underlying subsystems. For instance, the agent-based models which are increasingly popular for groundwater management studies can be made more useful by directly accounting for the hydrological processes which drive environmental outcomes. Conversely, conventional environmental models can benefit from an agent-based depiction of the feedbacks and heuristics which influence the decisions of groundwater users. From this perspective, this work describes a Python-based software architecture which couples the popular NetLogo agent-based platform with the MODFLOW/SEAWAT geohydrological modelling environment. This approach enables users to implement agent-based models in NetLogo's user-friendly platform, while benefiting from the full capabilities of MODFLOW/SEAWAT packages or reusing existing geohydrological models. The software architecture is based on the pyNetLogo connector, which provides an interface between the NetLogo agent-based modelling software and the Python programming language. This functionality is then extended and combined with Python's object-oriented features, to design a simulation architecture which couples NetLogo with MODFLOW/SEAWAT through the FloPy library (Bakker et al., 2016). The Python programming language also provides access to a range of external packages which can be used for testing and analysing the coupled models, which is illustrated for an application of Aquifer Thermal Energy Storage (ATES).

  7. Testing physical models for dipolar asymmetry with CMB polarization

    Science.gov (United States)

    Contreras, D.; Zibin, J. P.; Scott, D.; Banday, A. J.; Górski, K. M.

    2017-12-01

    The cosmic microwave background (CMB) temperature anisotropies exhibit a large-scale dipolar power asymmetry. To determine whether this is due to a real, physical modulation or is simply a large statistical fluctuation requires the measurement of new modes. Here we forecast how well CMB polarization data from Planck and future experiments will be able to confirm or constrain physical models for modulation. Fitting several such models to the Planck temperature data allows us to provide predictions for polarization asymmetry. While for some models and parameters Planck polarization will decrease error bars on the modulation amplitude by only a small percentage, we show, importantly, that cosmic-variance-limited (and in some cases even Planck) polarization data can decrease the errors by considerably better than the expectation of √{2 } based on simple ℓ-space arguments. We project that if the primordial fluctuations are truly modulated (with parameters as indicated by Planck temperature data) then Planck will be able to make a 2 σ detection of the modulation model with 20%-75% probability, increasing to 45%-99% when cosmic-variance-limited polarization is considered. We stress that these results are quite model dependent. Cosmic variance in temperature is important: combining statistically isotropic polarization with temperature data will spuriously increase the significance of the temperature signal with 30% probability for Planck.

  8. Complex between lignin and a Ti-based coupling agent

    DEFF Research Database (Denmark)

    Rasmussen, Jonas Stensgaard; Barsberg, Søren Talbro; Felby, Claus

    2014-01-01

    -fourier transform infrared spectroscopy in combination with first principle predictions based on the density functional theory (DFT). In the infrared spectra, a new band at 1586 cm-1 was identified and the DFT predictions confirmed that the new band is because of the covalent bonds in the form of ether linkages...... coating formulations would have a better performance if the adhesion to wood could be improved. In the present work, the chemical interaction between a titanium-based coupling agent, isopropyl triisostearoyl titanate (titanium agent, TA) and lignin has been studied by means of attenuated total reflectance...

  9. Scissors Mode of Dipolar Quantum Droplets of Dysprosium Atoms

    Science.gov (United States)

    Ferrier-Barbut, Igor; Wenzel, Matthias; Böttcher, Fabian; Langen, Tim; Isoard, Mathieu; Stringari, Sandro; Pfau, Tilman

    2018-04-01

    We report on the observation of the scissors mode of a single dipolar quantum droplet. The existence of this mode is due to the breaking of the rotational symmetry by the dipole-dipole interaction, which is fixed along an external homogeneous magnetic field. By modulating the orientation of this magnetic field, we introduce a new spectroscopic technique for studying dipolar quantum droplets. This provides a precise probe for interactions in the system, allowing us to extract a background scattering length for 164Dy of 69 (4 )a0 . Our results establish an analogy between quantum droplets and atomic nuclei, where the existence of the scissors mode is also only due to internal interactions. They further open the possibility to explore physics beyond the available theoretical models for strongly dipolar quantum gases.

  10. Microstrip Cross-coupled Interdigital SIR Based Bandpass Filter

    Directory of Open Access Journals (Sweden)

    R. K. Maharjan

    2012-09-01

    Full Text Available A simple and compact 4.9 GHz bandpass filter for C-band applications is proposed. This paper presents a novel microstrip cross-coupled interdigital half-wavelength stepped impedance resonator (SIR based bandpass filter (BPF.The designed structure is similar to that of a combination of two parallel interdigital capacitors. The scattering parameters of the structure are measured using vector network analyzer (VNA. The self generated capacitive and inductive reactances within the interdigital resonators exhibited in a resonance frequency of 4.9 GHz. The resonant frequency and bandwidth of the capacitive cross-coupled resonator is directly optimized from the physical arrangement of the resonators. The measured insertion loss (S21 and return loss (S11 were 0.3 dB and 28 dB, respectively, at resonance frequency which were almost close to the simulation results.

  11. Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid.

    Science.gov (United States)

    Sahin, Buyukdagli; Ralf, Blossey

    2014-07-16

    We study a model Coulomb fluid consisting of dipolar solvent molecules of finite extent which generalizes the point-like dipolar Poisson-Boltzmann model (DPB) previously introduced by Coalson and Duncan (1996 J. Phys. Chem. 100 2612) and Abrashkin et al (2007 Phys. Rev. Lett. 99 077801). We formulate a nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear dielectric response in this model for the case of a single plane geometry. Our results shed light on the relevance of nonlocal versus nonlinear effects in continuum models of material electrostatics.

  12. Harmonically trapped dipolar fermions in a two-dimensional square lattice

    DEFF Research Database (Denmark)

    Larsen, Anne-Louise G.; Bruun, Georg

    2012-01-01

    We consider dipolar fermions in a two-dimensional square lattice and a harmonic trapping potential. The anisotropy of the dipolar interaction combined with the lattice leads to transitions between phases with density order of different symmetries. We show that the attractive part of the dipolar...

  13. Photoswitchable molecular dipole antennas with tailored coherent coupling in glassy composite

    DEFF Research Database (Denmark)

    Elbahri, Mady; Zillohu, Ahnaf Usman; Gothe, Bastian

    2015-01-01

    . We also introduce the concept of 'tailored molecular photonic coupling' while highlighting the role of interferences for the design of optically active media by adjusting the photonic response of the medium with the real and imaginary refractive index of photoswitchable molecules in the 'ON' state...... alteration of photochromic molecular dipole antennas. We successfully demonstrate the concept of Brewster wavelength, which is based on the dipolar interaction between radiating dipoles and the surrounding matrix possessing a net dipole moment, as a key tool for highly localized sensing of matrix polarity....... Our results enhance our fundamental understanding of coherent dipole radiation and open a new vein of research based on glassy disordered dipolar composites that act as macroscopic antenna with cooperative action; furthermore, these results have important implications for new design rules of tailored...

  14. Synthesis of 1,4-naphthoquinone derivatives using 1,3-dipolar cycloaddition and Sonogashira reactions

    Directory of Open Access Journals (Sweden)

    Wilson Silva do Nascimento

    2010-04-01

    Full Text Available Naphthoquinones are known according to their important bio-activities, such as their antitumoral and topoisomerase inhibition properties. From 2-azido (3 or 2,3-diacetylene-1,4-naphthoquinone (4 it was possible to obtain triazole derivatives (naphthoquinonic. This work describes the synthesis of two novel molecules, with triazole groups linked to 1,4-naphthoquinone using the 1,3-dipolar cycloaddition and Sonogashira reactions. The synthetic strategy followed two routes (Scheme 1. First, we synthesized the 2-bromo-1,4-naphthoquinone (2, yield 98% by using Br2 and CH3CO2H, and then used it to obtain 2-azido-1,4-naphthoquinone (3, yield 62% from compound 1, along with ethanolic solution (reflux and NaN3. Finally, we prepared 1,2,3-triazole compounds (4a, b by 1,3-dipolar cycloaddition, involving compound (3 and terminal acetylenes (phenylacetylene, a and glycoside (b using Cu(OAc2 and ascorbate, under argon atmosphere. During the second step, 2,3-dibromo-1,4-naphthoquinone was prepared using Br2/CH2Cl2 at room temperature. From compound (5 it was possible to synthesize (6, catalyzed by Pd(PPh32Cl2/CuI/Et3N, under argon atmosphere, in 40% yield. The 1,3-dipolar cycloaddition reactions involving 2-azido-1,4-naphthoquinone (3 and alkynes (a, yield 23% and b, yield 30% were conducted using the solvent system, (1:1 terc-BuOH/H2O/r.t/ 20 mol% of Cu(OAc2 and sodium ascorbate, under stirring during 24 hours. The reaction involving 2,3-dibromo-1,4-naphthoquinone (5, yield 65% and phenylacetylene was prepared using the solvent mixture (2:1 DMSO/CHCl3 and catalytic amount of CuI/Pd(PPh32Cl2. The final products were characterized by elemental analysis and spectrometric techniques (IR, NMR 1H and 13C. Two novel triazole compounds were synthesized from naphthoquinones by 1,3-dipolar cycloaddition from suitable 1,4-naphthoquinones obtained by Sonogashira couplings.

  15. Electron dynamics during substorm dipolarization in Mercury's magnetosphere

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    2005-11-01

    Full Text Available We examine the nonlinear dynamics of electrons during the expansion phase of substorms at Mercury using test particle simulations. A simple model of magnetic field line dipolarization is designed by rescaling a magnetic field model of the Earth's magnetosphere. The results of the simulations demonstrate that electrons may be subjected to significant energization on the time scale (several seconds of the magnetic field reconfiguration. In a similar manner to ions in the near-Earth's magnetosphere, it is shown that low-energy (up to several tens of eV electrons may not conserve the second adiabatic invariant during dipolarization, which leads to clusters of bouncing particles in the innermost magnetotail. On the other hand, it is found that, because of the stretching of the magnetic field lines, high-energy electrons (several keVs and above do not behave adiabatically and possibly experience meandering (Speiser-type motion around the midplane. We show that dipolarization of the magnetic field lines may be responsible for significant, though transient, (a few seconds precipitation of energetic (several keVs electrons onto the planet's surface. Prominent injections of energetic trapped electrons toward the planet are also obtained as a result of dipolarization. These injections, however, do not exhibit short-lived temporal modulations, as observed by Mariner-10, which thus appear to follow from a different mechanism than a simple convection surge.

  16. Functionalization of Graphene via 1,3-Dipolar Cycloaddition

    NARCIS (Netherlands)

    Quintana, Mildred; Spyrou, Konstantinos; Grzelczak, Marek; Browne, Wesley R.; Rudolf, Petra; Prato, Maurizio

    Few-layer graphenes (FLG) produced by dispersion and exfoliation of graphite in N-methylpyrrolidone were successfully functionalized using the 1,3-dipolar cycloaddition of azomethine ylides. The amino functional groups attached to graphene sheets were quantified by the Kaiser test. These amino

  17. Dipolar fluid-wall systems. Beyond the image potential

    International Nuclear Information System (INIS)

    Boudh-hir, M.E.

    1989-02-01

    The case of dipolar fluid in front of an ideal wall is examined. The surface-fluid system is introduced as a limit case of a binary mixture Using the diagrammatic development, the expansion of the one-particle distribution function is given. 16 refs

  18. Diagnosis and Model Based Identification of a Coupling Misalignment

    Directory of Open Access Journals (Sweden)

    P. Pennacchi

    2005-01-01

    Full Text Available This paper is focused on the application of two different diagnostic techniques aimed to identify the most important faults in rotating machinery as well as on the simulation and prediction of the frequency response of rotating machines. The application of the two diagnostics techniques, the orbit shape analysis and the model based identification in the frequency domain, is described by means of an experimental case study that concerns a gas turbine-generator unit of a small power plant whose rotor-train was affected by an angular misalignment in a flexible coupling, caused by a wrong machine assembling. The fault type is identified by means of the orbit shape analysis, then the equivalent bending moments, which enable the shaft experimental vibrations to be simulated, have been identified using a model based identification method. These excitations have been used to predict the machine vibrations in a large rotating speed range inside which no monitoring data were available. To the best of the authors' knowledge, this is the first case of identification of coupling misalignment and prediction of the consequent machine behaviour in an actual size rotating machinery. The successful results obtained emphasise the usefulness of integrating common condition monitoring techniques with diagnostic strategies.

  19. Dipolar local field in homogeneously magnetized quasi-two-dimensional crystals

    International Nuclear Information System (INIS)

    Leon, H; Estevez-Rams, E

    2009-01-01

    A formalism to calculate the dipolar local field in homogeneously magnetized quasi-two-dimensional (Q2D) crystals is comprehensively presented. Two fundamental tests for this formalism are accomplished: the transition from the Q2D quantities to the corresponding 3D ones; and the recovering of the macroscopic quantities of the 3D continuum theory. The additive separation between lattice and shape contributions to the local field allows an unambiguous interpretation of the respective effects. Calculated demagnetization tensors for square and circular lateral geometries of dipole layers show that for a single crystal layer an extremely thin film, but still with a finite thickness, is a better physical representation than a strictly 2D plane. Distinct close-packed structures are simulated and calculations of the local field at the nodes of the stacked 2D lattices allow one to establish the number of significantly coupled dipole layers, depending on the ratio between the interlayer distance and the 2D lattice constant. The conclusions drawn are of interest for the study of the dipolar interaction in magnetic ultrathin films and other nanostructured materials, where magnetic nanoparticles are embedded in non-magnetic matrices.

  20. Effect of simple solutes on the long range dipolar correlations in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Baul, Upayan, E-mail: upayanb@imsc.res.in; Anishetty, Ramesh, E-mail: ramesha@imsc.res.in; Vemparala, Satyavani, E-mail: vani@imsc.res.in [The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113 (India); Kanth, J. Maruthi Pradeep, E-mail: jmpkanth@gmail.com [Vectra LLC, Mount Road, Chennai 600006 (India)

    2016-03-14

    Intermolecular correlations in liquid water at ambient conditions have generally been characterized through short range density fluctuations described through the atomic pair distribution functions. Recent numerical and experimental results have suggested that such a description of order or structure in liquid water is incomplete and there exist considerably longer ranged orientational correlations in water that can be studied through dipolar correlations. In this study, using large scale classical, atomistic molecular dynamics simulations using TIP4P-Ew and TIP3P models of water, we show that salts such as sodium chloride (NaCl), potassium chloride (KCl), caesium chloride (CsCl), and magnesium chloride (MgCl{sub 2}) have a long range effect on the dipolar correlations, which cannot be explained by the notion of structure making and breaking by dissolved ions. Observed effects are explained through orientational stratification of water molecules around ions and their long range coupling to the global hydrogen bond network by virtue of the sum rule for water. The observations for single hydrophilic solutes are contrasted with the same for a single methane (CH{sub 4}) molecule. We observe that even a single small hydrophobe can result in enhancement of long range orientational correlations in liquid water, contrary to the case of dissolved ions, which have been observed to have a reducing effect. The observations from this study are discussed in the context of hydrophobic effect.

  1. Study of gain-coupled distributed feedback laser based on high order surface gain-coupled gratings

    Science.gov (United States)

    Gao, Feng; Qin, Li; Chen, Yongyi; Jia, Peng; Chen, Chao; Cheng, LiWen; Chen, Hong; Liang, Lei; Zeng, Yugang; Zhang, Xing; Wu, Hao; Ning, Yongqiang; Wang, Lijun

    2018-03-01

    Single-longitudinal-mode, gain-coupled distributed feedback (DFB) lasers based on high order surface gain-coupled gratings are achieved. Periodic surface metal p-contacts with insulated grooves realize gain-coupled mechanism. To enhance gain contrast in the quantum wells without the introduction of effective index-coupled effect, groove length and depth were well designed. Our devices provided a single longitudinal mode with the maximum CW output power up to 48.8 mW/facet at 971.31 nm at 250 mA without facet coating, 3dB linewidth (39 dB). Optical bistable characteristic was observed with a threshold current difference. Experimentally, devices with different cavity lengths were contrasted on power-current and spectrum characteristics. Due to easy fabrication technique and stable performance, it provides a method of fabricating practical gain-coupled distributed feedback lasers for commercial applications.

  2. Identification of Coupled Map Lattice Based on Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Dong Xie

    2016-01-01

    Full Text Available A novel approach for the parameter identification of coupled map lattice (CML based on compressed sensing is presented in this paper. We establish a meaningful connection between these two seemingly unrelated study topics and identify the weighted parameters using the relevant recovery algorithms in compressed sensing. Specifically, we first transform the parameter identification problem of CML into the sparse recovery problem of underdetermined linear system. In fact, compressed sensing provides a feasible method to solve underdetermined linear system if the sensing matrix satisfies some suitable conditions, such as restricted isometry property (RIP and mutual coherence. Then we give a low bound on the mutual coherence of the coefficient matrix generated by the observed values of CML and also prove that it satisfies the RIP from a theoretical point of view. If the weighted vector of each element is sparse in the CML system, our proposed approach can recover all the weighted parameters using only about M samplings, which is far less than the number of the lattice elements N. Another important and significant advantage is that if the observed data are contaminated with some types of noises, our approach is still effective. In the simulations, we mainly show the effects of coupling parameter and noise on the recovery rate.

  3. New fluorescent dipolar pyrazine derivatives for non-doped red organic light-emitting diodes

    International Nuclear Information System (INIS)

    Gao Baoxiang; Zhou Quanguo; Geng Yanhou; Cheng Yanxiang; Ma Dongge; Xie Zhiyuan; Wang Lixiang; Wang Fosong

    2006-01-01

    Dipolar fluorescent compounds containing electron-accepting pyrazine-2,3-dicarbonitrile and electron-donating arylamine moiety have been designed and synthesized. The optical and electrochemical properties of these compounds can be adjusted by changing π-bridge length and the donor (D) strength. Organic light-emitting devices based on these compounds are fabricated. Saturated red emission of (0.67, 0.33) and the external quantum efficiency as high as 1.41% have been demonstrated for one of these compounds

  4. Event-based cluster synchronization of coupled genetic regulatory networks

    Science.gov (United States)

    Yue, Dandan; Guan, Zhi-Hong; Li, Tao; Liao, Rui-Quan; Liu, Feng; Lai, Qiang

    2017-09-01

    In this paper, the cluster synchronization of coupled genetic regulatory networks with a directed topology is studied by using the event-based strategy and pinning control. An event-triggered condition with a threshold consisting of the neighbors' discrete states at their own event time instants and a state-independent exponential decay function is proposed. The intra-cluster states information and extra-cluster states information are involved in the threshold in different ways. By using the Lyapunov function approach and the theories of matrices and inequalities, we establish the cluster synchronization criterion. It is shown that both the avoidance of continuous transmission of information and the exclusion of the Zeno behavior are ensured under the presented triggering condition. Explicit conditions on the parameters in the threshold are obtained for synchronization. The stability criterion of a single GRN is also given under the reduced triggering condition. Numerical examples are provided to validate the theoretical results.

  5. VIBRATION ANALYSIS OF TURBINE BASED ON FLUID-STRUCTURE COUPLING

    Institute of Scientific and Technical Information of China (English)

    LIU Demin; LIU Xiaobing

    2008-01-01

    The vibration of a Francis turbine is analyzed with the additional quality matrix method based on fluid-structure coupling (FSC). Firstly, the vibration frequency and mode of blade and runner in air and water are calculated. Secondly, the influences to runner frequency domain by large flow, small flow and design flow working conditions are compared. Finally the influences to runner modes by centrifugal forces under three rotating speeds of 400 r/min, 500 r/min and 600 r/min are compared. The centrifugal force and small flow working condition have greatly influence on the vibration of small runner. With the increase of centrifugal force, the vibration frequency of the runner is sharply increased. Some order frequencies are even close to the runner natural frequency in the air. Because the low frequency vibration will severely damage the stability of the turbine, low frequency vibration of units should be avoided as soon as possible.

  6. The detection of transient directional couplings based on phase synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, T; Fell, J; Lehnertz, K, E-mail: twagner@uni-bonn.d [Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany)

    2010-05-15

    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  7. The detection of transient directional couplings based on phase synchronization

    International Nuclear Information System (INIS)

    Wagner, T; Fell, J; Lehnertz, K

    2010-01-01

    We extend recent approaches based on the concept of phase synchronization to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the direction of transient interactions and assess its statistical significance using surrogate techniques. Analysing time series from noisy and chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings from an exemplary application to event-related brain activities underline the importance of our method for improving knowledge about the mechanisms underlying memory formation in humans.

  8. Color image encryption based on Coupled Nonlinear Chaotic Map

    International Nuclear Information System (INIS)

    Mazloom, Sahar; Eftekhari-Moghadam, Amir Masud

    2009-01-01

    Image encryption is somehow different from text encryption due to some inherent features of image such as bulk data capacity and high correlation among pixels, which are generally difficult to handle by conventional methods. The desirable cryptographic properties of the chaotic maps such as sensitivity to initial conditions and random-like behavior have attracted the attention of cryptographers to develop new encryption algorithms. Therefore, recent researches of image encryption algorithms have been increasingly based on chaotic systems, though the drawbacks of small key space and weak security in one-dimensional chaotic cryptosystems are obvious. This paper proposes a Coupled Nonlinear Chaotic Map, called CNCM, and a novel chaos-based image encryption algorithm to encrypt color images by using CNCM. The chaotic cryptography technique which used in this paper is a symmetric key cryptography with a stream cipher structure. In order to increase the security of the proposed algorithm, 240 bit-long secret key is used to generate the initial conditions and parameters of the chaotic map by making some algebraic transformations to the key. These transformations as well as the nonlinearity and coupling structure of the CNCM have enhanced the cryptosystem security. For getting higher security and higher complexity, the current paper employs the image size and color components to cryptosystem, thereby significantly increasing the resistance to known/chosen-plaintext attacks. The results of several experimental, statistical analysis and key sensitivity tests show that the proposed image encryption scheme provides an efficient and secure way for real-time image encryption and transmission.

  9. Coupled vertical-rocking response of base-isolated structures

    International Nuclear Information System (INIS)

    Pan, T.C.; Kelly, J.M.

    1984-01-01

    A base-isolated building can have a small horizontal eccentricity between the center of mass of the superstructure and the center of rigidity of the supporting bearings. The structure can be modeled as a rigid block with tributary masses supported on massless rubber bearings placed at a constant elevation below the center of mass. Perturbation methods are implemented to find the dynamic characteristics for both the detuned and the perfectly tuned cases. The Green's functions for the displacement response of the system are derived for the undamped and the damped conditions. The response spectrum modal superposition method is used in estimating the maximum acceleration. A simple method, accounting for the effect of closely spaced modes, is proposed for combining modal maxima and results in an approximate single-degree-of-freedom solution. This approximate solution may be used for thepreliminary design of a base-isolated structure. Numerical results for a base-isolated building subjected to the vertical component of the El Centro earthquake of 1940 were carried out for comparison with analytical results. It is shown that the effect of rocking coupling on the vertical seismic response of baseisolated structures can generally be neglected because of the combined effects of the time lag between the maximum translational and rotational responses and the influence of damping in the isolation system

  10. Quasi-parallel whistler mode waves observed by THEMIS during near-earth dipolarizations

    Directory of Open Access Journals (Sweden)

    O. Le Contel

    2009-06-01

    Full Text Available We report on quasi-parallel whistler emissions detected by the near-earth satellites of the THEMIS mission before, during, and after local dipolarization. These emissions are associated with an electron temperature anisotropy α=Te/T||e>1 consistent with the linear theory of whistler mode anisotropy instability. When the whistler mode emissions are observed the measured electron anisotropy varies inversely with β||e (the ratio of the electron parallel pressure to the magnetic pressure as predicted by Gary and Wang (1996. Narrow band whistler emissions correspond to the small α existing before dipolarization whereas the broad band emissions correspond to large α observed during and after dipolarization. The energy in the whistler mode is leaving the current sheet and is propagating along the background magnetic field, towards the Earth. A simple time-independent description based on the Liouville's theorem indicates that the electron temperature anisotropy decreases with the distance along the magnetic field from the equator. Once this variation of α is taken into account, the linear theory predicts an equatorial origin for the whistler mode. The linear theory is also consistent with the observed bandwidth of wave emissions. Yet, the anisotropy required to be fully consistent with the observations is somewhat larger than the measured one. Although the discrepancy remains within the instrumental error bars, this could be due to time-dependent effects which have been neglected. The possible role of the whistler waves in the substorm process is discussed.

  11. Ultrafast responses of dipolar and octupolar compounds with dipicolinate as an electron acceptor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yaochuan, E-mail: ycwang@dlmu.edu.cn [Department of Physics, Dalian Maritime University, Dalian 116026 (China); State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Liu, Siyuan; Liu, Dajun; Wang, Guiqiu [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Xiao, Haibo [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2016-11-01

    Two dipolar compounds with dipicolinate as electron acceptor group named trans-dimethyl-4-[4’-(N,N-dimethylamino)-styry1]-pyridin-2,6-dicarboxylate (M-1), trans-dimethyl-4-[4'-(N,N-diphenylamino)-styry1]-pyridin-2,6-dicarboxylate (P-1) as well as a P-1 based multi-branched octupolar compound {4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl) vinyl]}-N,N-bis{4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl)vinylphenyl]} aniline (P-3) with intense two-photon fluorescence emission properties are systematically investigated by using steady-state absorption and fluorescence spectroscopy, Z-scan, and two-photon excited fluorescence (TPF) method. The two-photon absorption cross section of octupolar compound P-3 in THF solution is determined to be 376 GM, which is approximately 12 times greater than that of dipolar counterpart P-1 (32 GM). Transient absorption spectroscopy is employed to investigate the excited state dynamics of the dipolar and octupolar compounds. The formation and relaxation lifetimes of the intra-molecular charge transfer (ICT) state are determined to be in the ranges of several picoseconds and several-hundreds of picoseconds, respectively, for all the three compounds in THF solutions. An extended π-conjugated system and increased intra-molecular cooperative effect are responsible for the observed large two-photon absorption character. - Highlights: • Octupolar compound gain 12-fold enhancement of two photon absorption. • Dynamic properties of intra-molecular charge transfer state are determined. • Cooperative effect is responsible for great increase of two photon character.

  12. Quantum phases of dipolar rotors on two-dimensional lattices.

    Science.gov (United States)

    Abolins, B P; Zillich, R E; Whaley, K B

    2018-03-14

    The quantum phase transitions of dipoles confined to the vertices of two-dimensional lattices of square and triangular geometry is studied using path integral ground state quantum Monte Carlo. We analyze the phase diagram as a function of the strength of both the dipolar interaction and a transverse electric field. The study reveals the existence of a class of orientational phases of quantum dipolar rotors whose properties are determined by the ratios between the strength of the anisotropic dipole-dipole interaction, the strength of the applied transverse field, and the rotational constant. For the triangular lattice, the generic orientationally disordered phase found at zero and weak values of both dipolar interaction strength and applied field is found to show a transition to a phase characterized by net polarization in the lattice plane as the strength of the dipole-dipole interaction is increased, independent of the strength of the applied transverse field, in addition to the expected transition to a transverse polarized phase as the electric field strength increases. The square lattice is also found to exhibit a transition from a disordered phase to an ordered phase as the dipole-dipole interaction strength is increased, as well as the expected transition to a transverse polarized phase as the electric field strength increases. In contrast to the situation with a triangular lattice, on square lattices, the ordered phase at high dipole-dipole interaction strength possesses a striped ordering. The properties of these quantum dipolar rotor phases are dominated by the anisotropy of the interaction and provide useful models for developing quantum phases beyond the well-known paradigms of spin Hamiltonian models, implementing in particular a novel physical realization of a quantum rotor-like Hamiltonian that possesses an anisotropic long range interaction.

  13. Quantum phases of dipolar rotors on two-dimensional lattices

    Science.gov (United States)

    Abolins, B. P.; Zillich, R. E.; Whaley, K. B.

    2018-03-01

    The quantum phase transitions of dipoles confined to the vertices of two-dimensional lattices of square and triangular geometry is studied using path integral ground state quantum Monte Carlo. We analyze the phase diagram as a function of the strength of both the dipolar interaction and a transverse electric field. The study reveals the existence of a class of orientational phases of quantum dipolar rotors whose properties are determined by the ratios between the strength of the anisotropic dipole-dipole interaction, the strength of the applied transverse field, and the rotational constant. For the triangular lattice, the generic orientationally disordered phase found at zero and weak values of both dipolar interaction strength and applied field is found to show a transition to a phase characterized by net polarization in the lattice plane as the strength of the dipole-dipole interaction is increased, independent of the strength of the applied transverse field, in addition to the expected transition to a transverse polarized phase as the electric field strength increases. The square lattice is also found to exhibit a transition from a disordered phase to an ordered phase as the dipole-dipole interaction strength is increased, as well as the expected transition to a transverse polarized phase as the electric field strength increases. In contrast to the situation with a triangular lattice, on square lattices, the ordered phase at high dipole-dipole interaction strength possesses a striped ordering. The properties of these quantum dipolar rotor phases are dominated by the anisotropy of the interaction and provide useful models for developing quantum phases beyond the well-known paradigms of spin Hamiltonian models, implementing in particular a novel physical realization of a quantum rotor-like Hamiltonian that possesses an anisotropic long range interaction.

  14. Coupling Strategies Investigation of Hybrid Atomistic-Continuum Method Based on State Variable Coupling

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2017-01-01

    Full Text Available Different configurations of coupling strategies influence greatly the accuracy and convergence of the simulation results in the hybrid atomistic-continuum method. This study aims to quantitatively investigate this effect and offer the guidance on how to choose the proper configuration of coupling strategies in the hybrid atomistic-continuum method. We first propose a hybrid molecular dynamics- (MD- continuum solver in LAMMPS and OpenFOAM that exchanges state variables between the atomistic region and the continuum region and evaluate different configurations of coupling strategies using the sudden start Couette flow, aiming to find the preferable configuration that delivers better accuracy and efficiency. The major findings are as follows: (1 the C→A region plays the most important role in the overlap region and the “4-layer-1” combination achieves the best precision with a fixed width of the overlap region; (2 the data exchanging operation only needs a few sampling points closer to the occasions of interactions and decreasing the coupling exchange operations can reduce the computational load with acceptable errors; (3 the nonperiodic boundary force model with a smoothing parameter of 0.1 and a finer parameter of 20 can not only achieve the minimum disturbance near the MD-continuum interface but also keep the simulation precision.

  15. Fluid model of inductively coupled plasma etcher based on COMSOL

    International Nuclear Information System (INIS)

    Cheng Jia; Ji Linhong; Zhu Yu; Shi Yixiang

    2010-01-01

    Fluid dynamic models are generally appropriate for the investigation of inductively coupled plasmas. A commercial ICP etcher filled with argon plasma is simulated in this study. The simulation is based on a multiphysical software, COMSOL(TM), which is a partial differential equation solver. Just as with other plasma fluid models, there are drift-diffusion approximations for ions, the quasi-neutrality assumption for electrons movements, reduced Maxwell equations for electromagnetic fields, electron energy equations for electron temperatures and the Navier-Stokes equation for neutral background gas. The two-dimensional distribution of plasma parameters are shown at 200 W of power and 1.33 Pa (10 mTorr) of pressure. Then the profile comparison of the electron number density and temperature with respect to power is illustrated. Finally we believe that there might be some disagreement between the predicted values and the real ones, and the reasons for this difference would be the Maxwellian eedf assumption and the lack of the cross sections of collisions and the reaction rates. (semiconductor physics)

  16. Digital chaotic sequence generator based on coupled chaotic systems

    International Nuclear Information System (INIS)

    Shu-Bo, Liu; Jing, Sun; Jin-Shuo, Liu; Zheng-Quan, Xu

    2009-01-01

    Chaotic systems perform well as a new rich source of cryptography and pseudo-random coding. Unfortunately their digital dynamical properties would degrade due to the finite computing precision. Proposed in this paper is a modified digital chaotic sequence generator based on chaotic logistic systems with a coupling structure where one chaotic subsystem generates perturbation signals to disturb the control parameter of the other one. The numerical simulations show that the length of chaotic orbits, the output distribution of chaotic system, and the security of chaotic sequences have been greatly improved. Moreover the chaotic sequence period can be extended at least by one order of magnitude longer than that of the uncoupled logistic system and the difficulty in decrypting increases 2 128 *2 128 times indicating that the dynamical degradation of digital chaos is effectively improved. A field programmable gate array (FPGA) implementation of an algorithm is given and the corresponding experiment shows that the output speed of the generated chaotic sequences can reach 571.4 Mbps indicating that the designed generator can be applied to the real-time video image encryption. (general)

  17. Evidence-Based Care for Couples With Infertility.

    Science.gov (United States)

    Stevenson, Eleanor L; Hershberger, Patricia E; Bergh, Paul A

    2016-01-01

    When couples cannot achieve pregnancy, they often seek health care from medical and nursing specialists. The care the couple receives begins with a thorough assessment to determine the possible cause of infertility and to plan appropriate care to ensure the best chance for the couple to have a biological child. In this article, we provide an overview of the etiology and evaluation of infertility, the various treatment options available, and the appropriate clinical implications. Copyright © 2016 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  18. Energy conversion and dissipation at dipolarization fronts: Theory, modeling and MMS observations

    Science.gov (United States)

    Sitnov, M. I.; Motoba, T.; Merkin, V. G.; Ohtani, S.; Cohen, I. J.; Mauk, B.; Vines, S. K.; Anderson, B. J.; Moore, T. E.; Torbert, R. B.; Giles, B. L.; Burch, J. L.

    2017-12-01

    Magnetic reconnection is one of the most important energy conversion mechanisms in space plasmas. In the classical picture it converts the energy of antiparallel magnetic fields into the kinetic and thermal energy of accelerated plasma particles in reconnection exhausts. It also involves energy dissipation near the X-line. This classical picture may be substantially modified in real space plasma configurations, such as the dayside magnetopause and the magnetotail. In particular, in the magnetotail the flows of accelerated particles may be strongly asymmetric along the tail with the domination of earthward flows. At the same time, strong energy conversion and even dissipation may occur away from the X-line, in particular, at dipolarization fronts. Here we present a theoretical picture of spontaneous magnetotail reconnection based on 3-D PIC simulations with the focus on plasma bulk flows, energy conversion and dissipation. This picture is compared with some observations from the MMS tail season. An important finding from these observations is that dipolarizations fronts may not only be regions of the total energy conversion with jE>0, but they may also be the sites of energy dissipation, both positive (jE'>0, E' is the electric field E in the system moving with one of the plasma species) and negative (jE'braking).

  19. Dipolar sources of the early scalp somatosensory evoked potentials to upper limb stimulation. Effect of increasing stimulus rates.

    Science.gov (United States)

    Valeriani, M; Restuccia, D; Di Lazzaro, V; Le Pera, D; Barba, C; Tonali, P; Mauguiere, F

    1998-06-01

    Brain electrical source analysis (BESA) of the scalp electroencephalographic activity is well adapted to distinguish neighbouring cerebral generators precisely. Therefore, we performed dipolar source modelling in scalp medium nerve somatosensory evoked potentials (SEPs) recorded at 1.5-Hz stimulation rate, where all the early components should be identifiable. We built a four-dipole model, which was issued from the grand average, and applied it also to recordings from single individuals. Our model included a dipole at the base of the skull and three other perirolandic dipoles. The first of the latter dipoles was tangentially oriented and was active at the same latencies as the N20/P20 potential and, with opposite polarity, the P24/N24 response. The second perirolandic dipole showed an initial peak of activity slightly earlier than that of the N20/P20 dipolar source and, later, it was active at the same latency as the central P22 potential. Lastly, the third perirolandic dipole explaining the fronto-central N30 potential scalp distribution was constantly more posterior than the first one. In order to evaluate the effect of an increasing repetition frequency on the activity of SEP dipolar sources, we applied the model built from 1.5-Hz SEPs to traces recorded at 3-Hz and 10-Hz repetition rates. We found that the 10-Hz stimulus frequency reduced selectively the later of the two activity phases of the first perirolandic dipole. The decrement in strength of this dipolar source can be explained if we assume that: (a) the later activity of the first perirolandic dipole can represent the inhibitory phase of a "primary response"; (b) two different clusters of cells generate the opposite activities of the tangential perirolandic dipole. An additional finding in our model was that two different perirolandic dipoles contribute to the centro-parietal N20 potential generation.

  20. Laser induced magnetization switching in a TbFeCo ferrimagnetic thin film: discerning the impact of dipolar fields, laser heating and laser helicity by XPEEM

    International Nuclear Information System (INIS)

    Gierster, L.; Ünal, A.A.; Pape, L.; Radu, F.; Kronast, F.

    2015-01-01

    We investigate laser induced magnetic switching in a ferrimagnetic thin film of Tb_2_2Fe_6_9Co_9 by PEEM. Using a small laser beam with a spot size of 3–5 µm in diameter in combination with high resolution magnetic soft X-ray microscopy we are able to discriminate between different effects that govern the microscopic switching process, namely the influence of the laser heating, of the helicity dependent momentum transfer, and of the dipolar coupling. Applying a sequence of femtosecond laser pulses to a previously saturated TbFeCo film leads to the formation of ring shaped magnetic structures in which all three effects can be observed. Laser helicity assisted switching is only observed in a narrow region within the Gaussian profile of the laser spot. Whereas in the center of the laser spot we find clear evidence for thermal demagnetization and in the outermost areas magnetic switching is determined by dipolar coupling with the surrounding film. Our findings demonstrate that by reducing the laser spot size the influence of dipolar coupling on laser induced switching is becoming increasingly important. - Highlights: • With a new PEEM sample holder a laser spot size of 3–5 µm in diameter is reached. • Spatial resolved imaging of laser induced magnetization reversal. • A single femtosecond laser pulse leads to a multi-domain state in TbFeCo. • A pulse sequence results in a ring-shaped magnetic pattern caused by dipolar fields. • Laser helicity dependent effects appear only in a narrow fluence region.

  1. The effect of dipolar interaction on the magnetic isotope effect

    DEFF Research Database (Denmark)

    Mojaza, Matin; Pedersen, Jørgen Boiden; Lukzen, Nikita

    2010-01-01

    A multi-channel kinetic description is used to study the magnetic isotope effect (MIE) in zero magnetic field. The maximal isotope effect is equal to the number of channels, two for the hyperfine interaction but four for the electron spin dipole–dipole interaction of the intermediate radical pair....... Quantum mechanical calculations agree with these conclusion and show that large MIE may be obtained even in the presence of a strong exchange interaction. The observed magnesium isotope effect on the rate of enzymatic synthesis of adenosine triphosphate (ATP) is approximately 3 implying that the dipolar...... interaction is responsible for the effect. Our calculations provide support for the proposed mechanism....

  2. Magnetic holes in the dipolarized magnetotail: ion and electron anisotropies

    Science.gov (United States)

    Shustov, P.; Artemyev, A.; Zhang, X. J.; Yushkov, E.; Petrukovich, A. A.

    2017-12-01

    We conduct statistics on magnetic holes observed by THEMIS spacecraft in the near-Earth magnetotail. Groups of holes are detected after dipolarizations in the quiet, equatorial plasma sheet. Magnetic holes are characterized by significant magnetic field depressions (up to 50%) and strong electron currents ( 10-50 nA/m2), with spatial scales much smaller than the ion gyroradius. These magnetic holes are populated by hot (>10 keV), transversely anisotropic electrons supporting the pressure balance. We present statistical properties of these sub-ion scale magnetic holes and discuss possible mechanisms on the hole formation.

  3. Dipolar interaction in arrays of magnetic nanotubes

    International Nuclear Information System (INIS)

    Velázquez-Galván, Y; Martínez-Huerta, J M; Encinas, A; De La Torre Medina, J; Danlée, Y; Piraux, L

    2014-01-01

    The dipolar interaction field in arrays of nickel nanotubes has been investigated on the basis of expressions derived from the effective demagnetizing field of the assembly as well as magnetometry measurements. The model incorporates explicitly the wall thickness and aspect ratio, as well as the spatial order of the nanotubes. The model and experiment show that the interaction field in nanotubes is smaller than that in solid nanowires due to the packing fraction reduction in tubes related to their inner cavity. Finally, good agreement between the model and experiment is found for the variation of the interaction field as a function of the tube wall thickness. (paper)

  4. Spreading dynamics of 2D dipolar Langmuir monolayer phases.

    Science.gov (United States)

    Heinig, P; Wurlitzer, S; Fischer, Th M

    2004-07-01

    We study the spreading of a liquid 2D dipolar droplet in a Langmuir monolayer. Interfacial tensions (line tensions) and microscopic contact angles depend on the scale on which they are probed and obey a scaling law. Assuming rapid equilibration of the microscopic contact angle and ideal slippage of the 2D solid/liquid and solid/gas boundary, the driving force of spreading is merely expressed by the shape-dependent long-range interaction integrals. We obtain good agreement between experiment and numerical simulations using this theory.

  5. Event-based simulation of networks with pulse delayed coupling

    Science.gov (United States)

    Klinshov, Vladimir; Nekorkin, Vladimir

    2017-10-01

    Pulse-mediated interactions are common in networks of different nature. Here we develop a general framework for simulation of networks with pulse delayed coupling. We introduce the discrete map governing the dynamics of such networks and describe the computation algorithm for its numerical simulation.

  6. A general A3: coupling reaction based on functionalized alkynes

    International Nuclear Information System (INIS)

    Wendler, Edison P.; Santos, Alcindo A. dos

    2013-01-01

    A range of hydroxypropargylpiperidones were efficiently obtained by a one-pot three-component coupling reaction of aldehydes, alkynols, and a primary amine equivalent (4-piperidone hydrochloride hydrate) in ethyl acetate using copper(I) chloride as a catalyst. The developed protocol proved to be equally efficient using a range of aliphatic aldehydes, including paraformaldehyde, and using protected and unprotected alkynols. (author)

  7. Incorporating Internet-based Interventions into Couple Therapy: Available Resources and Recommended Uses.

    Science.gov (United States)

    Cicila, Larisa N; Georgia, Emily J; Doss, Brian D

    2014-12-01

    Although there are a number of highly efficacious in-person treatments designed to ameliorate relationship distress, only a small proportion of distressed couples seek out in-person treatment. Recently developed internet-based interventions based on these in-person treatments are a promising way to circumvent common barriers to in-person treatment and give more distressed couples access to these efficacious interventions. The overarching aims of this review are to provide couple and family therapists with a broad overview of the available internet-based interventions and provide suggestions about how these interventions might be utilized before, during, or after in-person treatment. First, we review internet-based interventions targeting individual psychopathology (e.g. anxiety and depression). These interventions would be particularly useful as an adjunctive resource for in-person couple or family therapy when referrals for a concurrent in-person individual therapist are not feasible (because of time, financial, or geographic constraints). The majority of the review centers on internet-based interventions for distressed couples and covers four distinct types of resources: relationship advice websites, assessment/feedback interventions, enrichment interventions for satisfied couples, and interventions targeting at-risk or distressed couples. We close with a case study of one couple's journey through a newly developed intervention targeting at-risk couples, OurRelationship.com, and provide two appendices with information on currently available internet-based interventions.

  8. Geothermally Coupled Well-Based Compressed Air Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, C L [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bearden, Mark D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horner, Jacob A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Appriou, Delphine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-01

    . This project assessed the technical and economic feasibility of implementing geothermally coupled well-based CAES for grid-scale energy storage. Based on an evaluation of design specifications for a range of casing grades common in U.S. oil and gas fields, a 5-MW CAES project could be supported by twenty to twenty-five 5,000-foot, 7-inch wells using lower-grade casing, and as few as eight such wells for higher-end casing grades. Using this information, along with data on geothermal resources, well density, and potential future markets for energy storage systems, The Geysers geothermal field was selected to parameterize a case study to evaluate the potential match between the proven geothermal resource present at The Geysers and the field’s existing well infrastructure. Based on calculated wellbore compressed air mass, the study shows that a single average geothermal production well could provide enough geothermal energy to support a 15.4-MW (gross) power generation facility using 34 to 35 geothermal wells repurposed for compressed air storage, resulting in a simplified levelized cost of electricity (sLCOE) estimated at 11.2 ¢/kWh (Table S.1). Accounting for the power loss to the geothermal power project associated with diverting geothermal resources for air heating results in a net 2-MW decrease in generation capacity, increasing the CAES project’s sLCOE by 1.8 ¢/kWh.

  9. Geothermally Coupled Well-Based Compressed Air Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Casie L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bearden, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horner, Jacob A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cabe, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Appriou, Delphine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-20

    . This project assessed the technical and economic feasibility of implementing geothermally coupled well-based CAES for grid-scale energy storage. Based on an evaluation of design specifications for a range of casing grades common in U.S. oil and gas fields, a 5-MW CAES project could be supported by twenty to twenty-five 5,000-foot, 7-inch wells using lower-grade casing, and as few as eight such wells for higher-end casing grades. Using this information, along with data on geothermal resources, well density, and potential future markets for energy storage systems, The Geysers geothermal field was selected to parameterize a case study to evaluate the potential match between the proven geothermal resource present at The Geysers and the field’s existing well infrastructure. Based on calculated wellbore compressed air mass, the study shows that a single average geothermal production well could provide enough geothermal energy to support a 15.4-MW (gross) power generation facility using 34 to 35 geothermal wells repurposed for compressed air storage, resulting in a simplified levelized cost of electricity (sLCOE) estimated at 11.2 ¢/kWh (Table S.1). Accounting for the power loss to the geothermal power project associated with diverting geothermal resources for air heating results in a net 2-MW decrease in generation capacity, increasing the CAES project’s sLCOE by 1.8 ¢/kWh.

  10. A Coupled User Clustering Algorithm Based on Mixed Data for Web-Based Learning Systems

    Directory of Open Access Journals (Sweden)

    Ke Niu

    2015-01-01

    Full Text Available In traditional Web-based learning systems, due to insufficient learning behaviors analysis and personalized study guides, a few user clustering algorithms are introduced. While analyzing the behaviors with these algorithms, researchers generally focus on continuous data but easily neglect discrete data, each of which is generated from online learning actions. Moreover, there are implicit coupled interactions among the data but are frequently ignored in the introduced algorithms. Therefore, a mass of significant information which can positively affect clustering accuracy is neglected. To solve the above issues, we proposed a coupled user clustering algorithm for Wed-based learning systems by taking into account both discrete and continuous data, as well as intracoupled and intercoupled interactions of the data. The experiment result in this paper demonstrates the outperformance of the proposed algorithm.

  11. Coupling between chip based isotachophoresis and multi-collector inductively coupled plasma mass spectrometry for separation and measurement of lanthanides

    International Nuclear Information System (INIS)

    Vio, Laurent; Cretier, Gerard; Rocca, Jean-Louis; Chartier, Frederic; Geertsen, Valerie; Gourgiotis, Alkiviadis; Isnard, Helene; Morin, Pierre

    2012-01-01

    This paper presents the conception and fabrication of a micro-system for lanthanides separation and its coupling with a multi-collector inductively coupled plasma mass spectrometer for isotope ratio measurements. The lanthanides separation is based on the isotachophoresis technique and the micro-system conception has been adapted in order to fit with glove box limitations in view of future spent nuclear fuels analysis. The micro-device was tested by using a mixture of standard solutions of natural elements and the separation of 13 lanthanides was successfully performed. The micro-device was then coupled to a multi-collector inductively coupled plasma mass spectrometer for the on-line measurements of Nd and Sm isotope ratios. The isotopes of Nd and Sm were acquired online in multi-collection mode after separation of the two elements with an injection amount of 5 ng. Results obtained on the Nd and Sm isotope ratio measurements on transient signals are presented and discussed. (authors)

  12. Investigation on coupling error characteristics in angular rate matching based ship deformation measurement approach

    Science.gov (United States)

    Yang, Shuai; Wu, Wei; Wang, Xingshu; Xu, Zhiguang

    2018-01-01

    The coupling error in the measurement of ship hull deformation can significantly influence the attitude accuracy of the shipborne weapons and equipments. It is therefore important to study the characteristics of the coupling error. In this paper, an comprehensive investigation on the coupling error is reported, which has a potential of deducting the coupling error in the future. Firstly, the causes and characteristics of the coupling error are analyzed theoretically based on the basic theory of measuring ship deformation. Then, simulations are conducted for verifying the correctness of the theoretical analysis. Simulation results show that the cross-correlation between dynamic flexure and ship angular motion leads to the coupling error in measuring ship deformation, and coupling error increases with the correlation value between them. All the simulation results coincide with the theoretical analysis.

  13. Simulation of Octopus Arm Based on Coupled CPGs

    OpenAIRE

    Juan Tian; Qiang Lu

    2015-01-01

    The octopus arm has attracted many researchers’ interests and became a research hot spot because of its amazing features. Several dynamic models inspired by an octopus arm are presented to realize the structure with a large number of degrees of freedom. The octopus arm is made of a soft material introducing high-dimensionality, nonlinearity, and elasticity, which makes the octopus arm difficult to control. In this paper, three coupled central pattern generators (CPGs) are built and a 2-dimens...

  14. Evidence for several dipolar quasi-invariants in liquid crystals

    Science.gov (United States)

    Bonin, C. J.; González, C. E.; Segnorile, H. H.; Zamar, R. C.

    2013-10-01

    The quasi-equilibrium states of an observed quantum system involve as many constants of motion as the dimension of the operator basis which spans the blocks of all the degenerate eigenvalues of the Hamiltonian that drives the system dynamics, however, the possibility of observing such quasi-invariants in solid-like spin systems in Nuclear Magnetic Resonance (NMR) is not a strictly exact prediction. The aim of this work is to provide experimental evidence of several quasi-invariants, in the proton NMR of small spin clusters, like nematic liquid crystal molecules, in which the use of thermodynamic arguments is not justified. We explore the spin states prepared with the Jeener-Broekaert pulse sequence by analyzing the time-domain signals yielded by this sequence as a function of the preparation times, in a variety of dipolar networks, solids, and liquid crystals. We observe that the signals can be explained with two dipolar quasi-invariants only within a range of short preparation times, however at longer times liquid crystal signals show an echo-like behaviour whose description requires assuming more quasi-invariants. We study the multiple quantum coherence content of such signals on a basis orthogonal to the z-basis and see that such states involve a significant number of correlated spins. Therefore, we show that the NMR signals within the whole preparation time-scale can only be reconstructed by assuming the occurrence of multiple quasi-invariants which we experimentally isolate.

  15. Observation of roton mode population in a dipolar quantum gas

    Science.gov (United States)

    Chomaz, L.; van Bijnen, R. M. W.; Petter, D.; Faraoni, G.; Baier, S.; Becher, J. H.; Mark, M. J.; Wächtler, F.; Santos, L.; Ferlaino, F.

    2018-05-01

    The concept of a roton, a special kind of elementary excitation forming a minimum of energy at finite momentum, has been essential for the understanding of the properties of superfluid 4He (ref. 1). In quantum liquids, rotons arise from the strong interparticle interactions, whose microscopic description remains debated2. In the realm of highly controllable quantum gases, a roton mode has been predicted to emerge due to magnetic dipole-dipole interactions despite their weakly interacting character3. This prospect has raised considerable interest4-12; yet roton modes in dipolar quantum gases have remained elusive to observations. Here we report experimental and theoretical studies of the momentum distribution in Bose-Einstein condensates of highly magnetic erbium atoms, revealing the existence of the long-sought roton mode. Following an interaction quench, the roton mode manifests itself with the appearance of symmetric peaks at well-defined finite momentum. The roton momentum follows the predicted geometrical scaling with the inverse of the confinement length along the magnetization axis. From the growth of the roton population, we probe the roton softening of the excitation spectrum in time and extract the corresponding imaginary roton gap. Our results provide a further step in the quest towards supersolidity in dipolar quantum gases13.

  16. When Ethyl Isocyanoacetate Meets Isatins: A 1,3-Dipolar/Inverse 1,3-Dipolar/Olefination Reaction for Access to 3-Ylideneoxindoles.

    Science.gov (United States)

    Yuan, Wen-Kui; Cui, Tao; Liu, Wei; Wen, Li-Rong; Li, Ming

    2018-03-16

    A new CuI/1,10-phen-catalyzed reaction for the synthesis of 3-ylideneoxindoles from readily available isatins and ethyl isocyanoacetate, in which ethyl isocyanoacetate acts as a latent two-carbon donor like the Wittig reagent, is reported. A tandem procedure including 1,3-dipolar cycloaddition/inverse 1,3-dipolar ring opening/olefination allows the preparation of 3-ylideneoxindoles with broad functional group tolerance.

  17. Quantum Fluctuations in Quasi-One-Dimensional Dipolar Bose-Einstein Condensates.

    Science.gov (United States)

    Edler, D; Mishra, C; Wächtler, F; Nath, R; Sinha, S; Santos, L

    2017-08-04

    Recent experiments have revealed that beyond-mean-field corrections are much more relevant in weakly interacting dipolar condensates than in their nondipolar counterparts. We show that in quasi-one-dimensional geometries quantum corrections in dipolar and nondipolar condensates are strikingly different due to the peculiar momentum dependence of the dipolar interactions. The energy correction of the condensate presents not only a modified density dependence, but it may even change from attractive to repulsive at a critical density due to the surprising role played by the transversal directions. The anomalous quantum correction translates into a strongly modified physics for quantum-stabilized droplets and dipolar solitons. Moreover, and for similar reasons, quantum corrections of three-body correlations, and hence of three-body losses, are strongly modified by the dipolar interactions. This intriguing physics can be readily probed in current experiments with magnetic atoms.

  18. Stacking of purines in water: the role of dipolar interactions in caffeine.

    Science.gov (United States)

    Tavagnacco, L; Di Fonzo, S; D'Amico, F; Masciovecchio, C; Brady, J W; Cesàro, A

    2016-05-11

    During the last few decades it has been ascertained that base stacking is one of the major contributions stabilizing nucleic acid conformations. However, the understanding of the nature of the interactions involved in the stacking process remains under debate and it is a subject of theoretical and experimental studies. Structural similarity between purine bases (guanine and adenine) in DNA and the caffeine molecule makes caffeine an excellent model for the purine bases. The present study clearly shows that dipolar interactions play a fundamental role in determining stacking of purine molecules in solution. In order to reach this achievement, polarized ultraviolet Raman resonant scattering experiments have been carried out on caffeine aqueous solutions as a function of concentration and temperature. The investigation pointed out at the aggregation and solvation properties, particularly at elevated temperatures. Kubo-Anderson theory was used as a framework to investigate the non-coincidence effect (NCE) occurring in the totally symmetric breathing modes of the purine rings, and in the bending modes of the methyl groups of caffeine. The NCE concentration dependence shows that caffeine aggregation at 80 °C occurs by planar stacking of the hydrophobic faces. The data clearly indicate that dipolar interactions determine the reorientational motion of the molecules in solution and are the driving force for the stacking of caffeine. In parallel, the observed dephasing times imply a change in caffeine interactions as a function of temperature and concentration. A decrease, at low water content, of the dephasing time for the ring breathing vibration mode indicates that self-association alters the solvation structure that is detectable at low concentration. These results are in agreement with simulation predictions and serve as an important validation of the models used in those calculations.

  19. Pseudo-Random Number Generator Based on Coupled Map Lattices

    Science.gov (United States)

    Lü, Huaping; Wang, Shihong; Hu, Gang

    A one-way coupled chaotic map lattice is used for generating pseudo-random numbers. It is shown that with suitable cooperative applications of both chaotic and conventional approaches, the output of the spatiotemporally chaotic system can easily meet the practical requirements of random numbers, i.e., excellent random statistical properties, long periodicity of computer realizations, and fast speed of random number generations. This pseudo-random number generator system can be used as ideal synchronous and self-synchronizing stream cipher systems for secure communications.

  20. Coupled-oscillator based active-array antennas

    CERN Document Server

    Pogorzelski, Ronald J

    2012-01-01

    Describing an innovative approach to phased-array control in antenna design This book explores in detail phased-array antennas that use coupled-oscillator arrays, an arrangement featuring a remarkably simple beam steering control system and a major reduction in complexity compared with traditional methods of phased-array control. It brings together in one convenient, self-contained volume the many salient research results obtained over the past ten to fifteen years in laboratories around the world, including the California Institute of Technology's Jet Propulsion Laboratory.

  1. High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions

    DEFF Research Database (Denmark)

    Stamate, Eugen; Draghici, M.

    2012-01-01

    A large area plasma source based on 12 multi-dipolar ECR plasma cells arranged in a 3 x 4 matrix configuration was built and optimized for silicon etching by negative ions. The density ratio of negative ions to electrons has exceeded 300 in Ar/SF6 gas mixture when a magnetic filter was used...... to reduce the electron temperature to about 1.2 eV. Mass spectrometry and electrostatic probe were used for plasma diagnostics. The new source is free of density jumps and instabilities and shows a very good stability for plasma potential, and the dominant negative ion species is F-. The magnetic field...... in plasma volume is negligible and there is no contamination by filaments. The etching rate by negative ions measured in Ar/SF6/O-2 mixtures was almost similar with that by positive ions reaching 700 nm/min. (C) 2012 American Institute of Physics...

  2. Magnetospheric Multiscale (MMS) Observations of Energetic Ion Response to Magnetotail Dipolarization Events

    Science.gov (United States)

    Cohen, I. J.; Mauk, B.; Anderson, B. J.; Sitnov, M. I.; Motoba, T.; Ohtani, S.; Gkioulidou, M.; Fuselier, S. A.; Giles, B. L.; Strangeway, R. J.; Torbert, R. B.; Burch, J. L.

    2017-12-01

    Observations from the Energetic Ion Spectrometer (EIS) instruments aboard MMS have shown angular (pitch, elevation, azimuthal) asymmetries of energetic (>10s of keV) ions corresponding to dipolarization events in the near-Earth and distant magnetotail. In particular, EIS distinguishes the species composition of these ions (protons, helium, oxygen) and reveals apparent species-based differences in their response. This study presents analysis of the dynamic injection and mass-dependent response of energetic ions that likely result from the kinetic response of the ions to the time-varying electric and magnetic fields associated with injection process. Analysis is focused on discriminating between truly kinetic responses to the dynamics and the features that arise from large gyro-radii particles in the vicinity of strong spatial gradients. The study will focus on EIS measurements and include supplementary data from the FIELDS, FPI, and HPCA instruments.

  3. Hybrid Coupling of Laser Light sources to Silicon (Oxy)Nitride Based Waveguides

    NARCIS (Netherlands)

    Krijger, A.J.T. de; Bekman, H.H.P.T.

    1997-01-01

    An efficient method was developed to couple a diode laser to a high contrast waveguides. The laserdiodes were mounted with sub-micron precision using a thermocompression mounting technique. An AlGaAs (λ = 850 nm) laserdiode was coupled to a SiON based slab waveguide (efficiency η EQ 25 - 30%) and to

  4. AREVA main steam line break fully coupled methodology based on CATHARE-ARTEMIS - 15496

    International Nuclear Information System (INIS)

    Denis, L.; Jasserand, L.; Tomatis, D.; Segond, M.; Royere, C.; Sauvage, J.Y.

    2015-01-01

    The CATHARE code developed since 1979 by AREVA, CEA, EDF and IRSN is one of the major thermal-hydraulic system codes worldwide. In order to have at disposal realistic methodologies based on CATHARE for the whole transient and accident analysis in Chapter 15 of Safety Reports, a coupling with the code ARTEMIS was developed. ARTEMIS is the core code in AREVA's new reactor simulator system ARCADIA, using COBRA-FLX to model the thermal-hydraulics in the core. The Fully Coupled Methodology was adapted to the CATHARE-ARTEMIS coupling to perform Main Steam Line Break studies. This methodology, originally applied to the MANTA-SMART-FLICA coupling, is dedicated to Main Steam Line Break transients at zero power. The aim of this paper is to present the coupling between CATHARE and ARTEMIS and the application of the Fully Coupled Methodology in a different code environment. (authors)

  5. Hybrid method based on embedded coupled simulation of vortex particles in grid based solution

    Science.gov (United States)

    Kornev, Nikolai

    2017-09-01

    The paper presents a novel hybrid approach developed to improve the resolution of concentrated vortices in computational fluid mechanics. The method is based on combination of a grid based and the grid free computational vortex (CVM) methods. The large scale flow structures are simulated on the grid whereas the concentrated structures are modeled using CVM. Due to this combination the advantages of both methods are strengthened whereas the disadvantages are diminished. The procedure of the separation of small concentrated vortices from the large scale ones is based on LES filtering idea. The flow dynamics is governed by two coupled transport equations taking two-way interaction between large and fine structures into account. The fine structures are mapped back to the grid if their size grows due to diffusion. Algorithmic aspects of the hybrid method are discussed. Advantages of the new approach are illustrated on some simple two dimensional canonical flows containing concentrated vortices.

  6. Layers of Cold Dipolar Molecules in the Harmonic Approximation

    DEFF Research Database (Denmark)

    R. Armstrong, J.; Zinner, Nikolaj Thomas; V. Fedorov, D.

    2012-01-01

    We consider the N-body problem in a layered geometry containing cold polar molecules with dipole moments that are polarized perpendicular to the layers. A harmonic approximation is used to simplify the hamiltonian and bound state properties of the two-body inter-layer dipolar potential are used...... to adjust this effective interaction. To model the intra-layer repulsion of the polar molecules, we introduce a repulsive inter-molecule potential that can be parametrically varied. Single chains containing one molecule in each layer, as well as multi-chain structures in many layers are discussed...... and their energies and radii determined. We extract the normal modes of the various systems as measures of their volatility and eventually of instability, and compare our findings to the excitations in crystals. We find modes that can be classified as either chains vibrating in phase or as layers vibrating against...

  7. Electron Jet Detected by MMS at Dipolarization Front

    Science.gov (United States)

    Liu, C. M.; Fu, H. S.; Vaivads, A.; Khotyaintsev, Y. V.; Gershman, D. J.; Hwang, K.-J.; Chen, Z. Z.; Cao, D.; Xu, Y.; Yang, J.; Peng, F. Z.; Huang, S. Y.; Burch, J. L.; Giles, B. L.; Ergun, R. E.; Russell, C. T.; Lindqvist, P.-A.; Le Contel, O.

    2018-01-01

    Using MMS high-resolution measurements, we present the first observation of fast electron jet (Ve 2,000 km/s) at a dipolarization front (DF) in the magnetotail plasma sheet. This jet, with scale comparable to the DF thickness ( 0.9 di), is primarily in the tangential plane to the DF current sheet and mainly undergoes the E × B drift motion; it contributes significantly to the current system at the DF, including a localized ring-current that can modify the DF topology. Associated with this fast jet, we observed a persistent normal electric field, strong lower hybrid drift waves, and strong energy conversion at the DF. Such strong energy conversion is primarily attributed to the electron-jet-driven current (E ṡ je ≈ 2 E ṡ ji), rather than the ion current suggested in previous studies.

  8. Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition

    Directory of Open Access Journals (Sweden)

    Peter Ertl

    1997-04-01

    Full Text Available The cycloaddition of the chiral nitrile oxide 1 to 1-R-substituted 3,3-methylene-5,5-dimethyl-2-pyrrolidinones 2 (where R is H, n-butyl-, 1,1-dimethylethoxycarbonyl-, 1-methylethenyl- and acetyl- proceeds regioselectively under the formation of spiroisoxazolines, namely 7-R-substituted-6-oxo-8,8-dimethyl-1-oxa-2,7-diazaspiro[4,4]non-2-enes 5 and 6. The asymmetric induction expected by the a-chiral centre of the nitrile oxide 1 was not very effective, diastereoisomers 5 and 6 were formed in an approximate 50:50 ratio. The stereoselectivity of the 1,3-dipolar cycloaddition of the arylnitrile oxide 7 with the chiral lactam 3 and the achiral lactone 4 are investigated. The attack of the 1,3-dipole occurred from the less hindered face of the dipolarophile 3 and 4, giving the major isomer 8 and 10, respectively.

  9. Nuclear dipolar magnetism around one microkelvin in calciumhydroxide

    International Nuclear Information System (INIS)

    Marks, J.

    1985-01-01

    This thesis is devoted to a study of dipolar magnetism of the proton spins in Ca(OH) 2 . First, cooling techniques are described. The energy of different spin configurations are calculated in the Weiss-field approximation. Crystallographic characteristics of Ca(OH) 2 are described, as well as a method to produce monocrystals and a method for crystal doping using 1.5 MeV electron beams. It is shown that the polarization mechanism of the proton spins in Ca(OH) 2 doped with O 2 - centra is the 'Solid Effect'. Susceptibility measurements are presented as a function of the polarization. Results imply that both at positive and at negative temperatures state ordering sets in, characterized by a plateau in the susceptibility. (Auth/G.J.P.)

  10. Hidden magnetism in periodically modulated one dimensional dipolar fermions

    Science.gov (United States)

    Fazzini, S.; Montorsi, A.; Roncaglia, M.; Barbiero, L.

    2017-12-01

    The experimental realization of time-dependent ultracold lattice systems has paved the way towards the implementation of new Hubbard-like Hamiltonians. We show that in a one-dimensional two-components lattice dipolar Fermi gas the competition between long range repulsion and correlated hopping induced by periodically modulated on-site interaction allows for the formation of hidden magnetic phases, with degenerate protected edge modes. The magnetism, characterized solely by string-like nonlocal order parameters, manifests in the charge and/or in the spin degrees of freedom. Such behavior is enlighten by employing Luttinger liquid theory and numerical methods. The range of parameters for which hidden magnetism is present can be reached by means of the currently available experimental setups and probes.

  11. Drag Effect in Double-Layer Dipolar Fermi Gases

    International Nuclear Information System (INIS)

    Tanatar, B; Renklioglu, B; Oktel, M O

    2014-01-01

    We consider two parallel layers of two-dimensional spin-polarized dipolar Fermi gas without any tunneling between the layers. The effective interactions describing screening and correlation effects between the dipoles in a single layer (intra-layer) and across the layers (interlayer) are modeled within the Hubbard approximation. We calculate the rate of momentum transfer between the layers when the gas in one layer has a steady flow. The momentum transfer induces a steady flow in the second layer which is assumed initially at rest. This is the drag effect familiar from double-layer semiconductor and graphene structures. Our calculations show that the momentum relaxation time has temperature dependence similar to that in layers with charged particles which we think is related to the contributions from the collective modes of the system

  12. Particle-in-cell Simulation of Dipolarization Front Associated Whistlers

    Science.gov (United States)

    Lin, D.; Scales, W.; Ganguli, G.; Crabtree, C. E.

    2017-12-01

    Dipolarization fronts (DFs) are dipolarized magnetic field embedded in the Earthward propagating bursty bulk flows (BBFs), which separates the hot, tenuous high-speed flow from the cold, dense, and slowly convecting surrounding plasma [Runov et al. 2011]. Broadband fluctuations have been observed at DFs including the electromagnetic whistler waves and electrostatic lower hybrid waves in the Very Low Frequency (VLF) range [e.g., Zhou et al. 2009, Deng et al. 2010]. There waves are suggested to be able heat electrons and play a critical role in the plasma sheet dynamics [Chaston et al., 2012, Angelopoulos et al., 2013]. However, their generation mechanism and role in the energy conversion are still under debate. The gradient scale of magnetic field, plasma density at DFs in the near-Earth magnetotail is comparable to or lower than the ion gyro radius [Runov et al., 2011, Fu et al., 2012, Breuillard et al., 2016]. Such strongly inhomogeneous configuration could be unstable to the electron-ion hybrid (EIH) instability, which arises from strongly sheared transverse flow and is in the VLF range [Ganguli et al. 1988, Ganguli et al. 2014]. The equilibrium of the EIH theory implies an anisotropy of electron temperature, which are likely to drive the whistler waves observed in DFs [Deng et al., 2010, Gary et al., 2011]. In order to better understand how the whistler waves are generated in DFs and whether the EIH theory is applicable, a fully electromagnetic particle-in-cell (EMPIC) model is used to simulate the EIH instability with similar equilibrium configurations in DF observations. The EMPIC model deals with three dimensions in the velocity space and two dimensions in the configuration space, which is quite ready to include the third configuration dimension. Simulation results will be shown in this presentation.

  13. Energetic Electron Acceleration and Injection During Dipolarization Events in Mercury's Magnetotail

    Science.gov (United States)

    Dewey, Ryan M.; Slavin, James A.; Raines, Jim M.; Baker, Daniel N.; Lawrence, David J.

    2017-12-01

    Energetic particle bursts associated with dipolarization events within Mercury's magnetosphere were first observed by Mariner 10. The events appear analogous to particle injections accompanying dipolarization events at Earth. The Energetic Particle Spectrometer (3 s resolution) aboard MESSENGER determined the particle bursts are composed entirely of electrons with energies ≳ 300 keV. Here we use the Gamma-Ray Spectrometer high-time-resolution (10 ms) energetic electron measurements to examine the relationship between energetic electron injections and magnetic field dipolarization in Mercury's magnetotail. Between March 2013 and April 2015, we identify 2,976 electron burst events within Mercury's magnetotail, 538 of which are closely associated with dipolarization events. These dipolarizations are detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. Similar to those at Earth, we find that these dipolarizations appear to be low-entropy, depleted flux tubes convecting planetward following the collapse of the inner magnetotail. We find that electrons experience brief, yet intense, betatron and Fermi acceleration during these dipolarizations, reaching energies 130 keV and contributing to nightside precipitation. Thermal protons experience only modest betatron acceleration. While only 25% of energetic electron events in Mercury's magnetotail are directly associated with dipolarization, the remaining events are consistent with the Near-Mercury Neutral Line model of magnetotail injection and eastward drift about Mercury, finding that electrons may participate in Shabansky-like closed drifts about the planet. Magnetotail dipolarization may be the dominant source of energetic electron acceleration in Mercury's magnetosphere.

  14. Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

    Energy Technology Data Exchange (ETDEWEB)

    Spizzo, F., E-mail: spizzo@fe.infn.it [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia and CNISM, Università di Perugia, I-06123 Perugia (Italy); Chinni, F.; Bonfiglioli, E. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Gerardino, A. [Istituto di Fotonica e Nanotecnologie, CNR, I-00156 Roma (Italy); Barucca, G. [Dipartimento SIMAU, Università Politecnica delle Marche, I-60131 Ancona (Italy); Bisero, D.; Fin, S.; Del Bianco, L. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy)

    2016-02-15

    We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm{sup 2}) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H{sub EX} measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H{sub EX} and of the coercivity H{sub C} are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H{sub EX}~90 Oe and H{sub C}~180 Oe in the dots and H{sub EX}~1270 Oe and H{sub C}~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K

  15. Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

    International Nuclear Information System (INIS)

    Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Gerardino, A.; Barucca, G.; Bisero, D.; Fin, S.; Del Bianco, L.

    2016-01-01

    We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm"2) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H_E_X measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H_E_X and of the coercivity H_C are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H_E_X~90 Oe and H_C~180 Oe in the dots and H_E_X~1270 Oe and H_C~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K • Confinement of IrMn magnetic

  16. Simulation of Octopus Arm Based on Coupled CPGs

    Directory of Open Access Journals (Sweden)

    Juan Tian

    2015-01-01

    Full Text Available The octopus arm has attracted many researchers’ interests and became a research hot spot because of its amazing features. Several dynamic models inspired by an octopus arm are presented to realize the structure with a large number of degrees of freedom. The octopus arm is made of a soft material introducing high-dimensionality, nonlinearity, and elasticity, which makes the octopus arm difficult to control. In this paper, three coupled central pattern generators (CPGs are built and a 2-dimensional dynamic model of the octopus arm is presented to explore possible strategies of the octopus movement control. And the CPGs’ signals treated as activation are added on the ventral, dorsal, and transversal sides, respectively. The effects of the octopus arm are discussed when the parameters of the CPGs are changed. Simulations show that the octopus arm movements are mainly determined by the shapes of three CPGs’ phase diagrams. Therefore, some locomotion modes are supposed to be embedded in the neuromuscular system of the octopus arm. And the octopus arm movements can be achieved by modulating the parameters of the CPGs. The results are beneficial for researchers to understand the octopus movement further.

  17. Optical Switching Using Transition from Dipolar to Charge Transfer Plasmon Modes in Ge2Sb2Te5 Bridged Metallodielectric Dimers

    Science.gov (United States)

    Ahmadivand, Arash; Gerislioglu, Burak; Sinha, Raju; Karabiyik, Mustafa; Pala, Nezih

    2017-02-01

    Capacitive coupling and direct shuttling of charges in nanoscale plasmonic components across a dielectric spacer and through a conductive junction lead to excitation of significantly different dipolar and charge transfer plasmon (CTP) resonances, respectively. Here, we demonstrate the excitation of dipolar and CTP resonant modes in metallic nanodimers bridged by phase-change material (PCM) sections, material and electrical characteristics of which can be controlled by external stimuli. Ultrafast switching (in the range of a few nanoseconds) between amorphous and crystalline phases of the PCM section (here Ge2Sb2Te5 (GST)) allows for designing a tunable plasmonic switch for optical communication applications with significant modulation depth (up to 88%). Judiciously selecting the geometrical parameters and taking advantage of the electrical properties of the amorphous phase of the GST section we adjusted the extinction peak of the dipolar mode at the telecommunication band (λ~1.55 μm), which is considered as the OFF state. Changing the GST phase to crystalline via optical heating allows for direct transfer of charges through the junction between nanodisks and formation of a distinct CTP peak at longer wavelengths (λ~1.85 μm) far from the telecommunication wavelength, which constitutes the ON state.

  18. Tight Coupling of Metabolic Oscillations and Intracellular Water Dynamics in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Thoke, Henrik Seir; Tobiesen, Asger; Brewer, Jonathan R.

    2015-01-01

    We detected very strong coupling between the oscillating concentration of ATP and the dynamics of intracellular water during glycolysis in Saccharomyces cerevisiae. Our results indicate that: i) dipolar relaxation of intracellular water is heterogeneous within the cell and different from dilute...... conditions, ii) water dipolar relaxation oscillates with glycolysis and in phase with ATP concentration, iii) this phenomenon is scale-invariant from the subcellular to the ensemble of synchronized cells and, iv) the periodicity of both glycolytic oscillations and dipolar relaxation are equally affected by D...

  19. Chiral-glass transition in a diluted dipolar-interaction Heisenberg system

    International Nuclear Information System (INIS)

    Zhang Kaicheng; Liu Guibin; Zhu Yan

    2011-01-01

    Recently, numerical simulations reveal that a spin-glass transition can occur in the three-dimensional diluted dipolar system. By defining the chirality of triple spins in a diluted dipolar Heisenberg spin glass, we study the chiral ordering in the system using parallel tempering algorithm and heat bath method. The finite-size scaling analysis reveals that the system undergoes a chiral-glass transition at finite temperature. - Highlights: → We define the chirality in a diluted dipolar Heisenberg system. → The system undergoes a chiral-glass transition at finite temperature. → We extract the critical exponents of the chiral-glass transition.

  20. Many-body formation and dissociation of a dipolar chain crystal

    International Nuclear Information System (INIS)

    You, Jhih-Shih; Wang, Daw-Wei

    2014-01-01

    We propose an experimental scheme to effectively assemble chains of dipolar gases with a uniform length in a multi-layer system. The obtained dipolar chains can form a chain crystal with the system temperature easily controlled by the initial lattice potential and the external field strength during processing. When the density of chains increases, we further observe a second order quantum phase transition for the chain crystal to be dissociated toward layers of 2D crystal, where the quantum fluctuation dominates the classical energy and the compressibility diverges at the phase boundary. The experimental implication of such a dipolar chain crystal and its quantum phase transition is also discussed. (paper)

  1. The Bodenmann Couples Coping Enhancement Training (CCET): A New Approach to Prevention of Marital Distress Based upon Stress and Coping

    Science.gov (United States)

    Bodenmann, Guy; Shantinath, S. D.

    2004-01-01

    We describe a distress prevention training program for couples and three empirical studies that support its effectiveness. The program, Couples Coping Enhancement Training (CCET), is based both upon stress and coping theory and research on couples. In addition to traditional elements of couples programs (e.g., communication and problem-solving…

  2. Plasma-based localized defect for switchable coupling applications

    International Nuclear Information System (INIS)

    Varault, Stefan; Gabard, Benjamin; Sokoloff, Jerome; Bolioli, Sylvain

    2011-01-01

    We report in this paper experimental measurements in order to validate the concept of switchable electromagnetic band gap filters based on plasma capillaries in the microwave regime. The plasma tube is embedded inside the structure to create a bistable (plasma on or off) punctual defect. We first investigate two kinds of discharge tubes: Ar-Hg and pure Ne, which we then use to experimentally achieve plasma-based reconfigurable applications, namely, a two-port coupler and a two-port demultiplexer.

  3. On the Acceleration and Anisotropy of Ions Within Magnetotail Dipolarizing Flux Bundles

    Science.gov (United States)

    Zhou, Xu-Zhi; Runov, Andrei; Angelopoulos, Vassilis; Artemyev, Anton V.; Birn, Joachim

    2018-01-01

    Dipolarizing flux bundles (DFBs), earthward propagating structures with enhanced northward magnetic field Bz, are usually believed to carry a distinctly different plasma population from that in the ambient magnetotail plasma sheet. The ion distribution functions within the DFB, however, have been recently found to be largely controlled by the ion adiabaticity parameter κ in the ambient plasma sheet outside the DFB. According to these observations, the ambient κ values of 2-3 usually correspond to a strong perpendicular anisotropy of suprathermal ions within the DFB, whereas for lower κ values the DFB ions become more isotropic. Here we utilize a simple, test particle model to explore the nature of the anisotropy and its dependence on the ambient κ values. We find that the anisotropy originates from successive ion reflections and reentries to the DFB, during which the ions are consecutively accelerated in the perpendicular direction by the DFB-associated electric field. This consecutive acceleration may be interrupted, however, when magnetic field lines are highly curved in the ambient plasma sheet. In this case, the ion trajectories become stochastic outside the DFB, which makes the reflected ions less likely to return to the DFB for another cycle of acceleration; as a consequence, the perpendicular ion anisotropy does not appear. Given that the DFB ions are a free energy source for instabilities when they are injected toward Earth, our simple model (that reproduces most observational features on the anisotropic DFB ion distributions) may shed new lights on the coupling process between magnetotail and inner magnetosphere.

  4. Study on frequency characteristics of wireless power transmission system based on magnetic coupling resonance

    Science.gov (United States)

    Liang, L. H.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Yue, Z. K.; Cui, S.

    2017-11-01

    In order to study the frequency characteristics of the wireless energy transmission system based on the magnetic coupling resonance, a circuit model based on the magnetic coupling resonant wireless energy transmission system is established. The influence of the load on the frequency characteristics of the wireless power transmission system is analysed. The circuit coupling theory is used to derive the minimum load required to suppress frequency splitting. Simulation and experimental results verify that when the load size is lower than a certain value, the system will appear frequency splitting, increasing the load size can effectively suppress the frequency splitting phenomenon. The power regulation scheme of the wireless charging system based on magnetic coupling resonance is given. This study provides a theoretical basis for load selection and power regulation of wireless power transmission systems.

  5. Interseismic Coupling-Based Earthquake and Tsunami Scenarios for the Nankai Trough

    Science.gov (United States)

    Baranes, H.; Woodruff, J. D.; Loveless, J. P.; Hyodo, M.

    2018-04-01

    Theoretical modeling and investigations of recent subduction zone earthquakes show that geodetic estimates of interseismic coupling and the spatial distribution of coseismic rupture are correlated. However, the utility of contemporary coupling in guiding construction of rupture scenarios has not been evaluated on the world's most hazardous faults. Here we demonstrate methods for scaling coupling to slip to create rupture models for southwestern Japan's Nankai Trough. Results show that coupling-based models produce distributions of ground surface deformation and tsunami inundation that are similar to historical and geologic records of the largest known Nankai earthquake in CE 1707 and to an independent, quasi-dynamic rupture model. Notably, these models and records all support focused subsidence around western Shikoku that makes the region particularly vulnerable to flooding. Results imply that contemporary coupling mirrors the slip distribution of a full-margin, 1707-type rupture, and Global Positioning System measurements of surface motion are connected with the trough's physical characteristics.

  6. Integrated approach for fusion multi-physics coupled analyses based on hybrid CAD and mesh geometries

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Yuefeng, E-mail: yuefeng.qiu@kit.edu; Lu, Lei; Fischer, Ulrich

    2015-10-15

    Highlights: • Integrated approach for neutronics, thermal and structural analyses was developed. • MCNP5/6, TRIPOLI-4 were coupled with CFX, Fluent and ANSYS Workbench. • A novel meshing approach has been proposed for describing MC geometry. - Abstract: Coupled multi-physics analyses on fusion reactor devices require high-fidelity neutronic models, and flexible, accurate data exchanging between various calculation codes. An integrated coupling approach has been developed to enable the conversion of CAD, mesh, or hybrid geometries for Monte Carlo (MC) codes MCNP5/6, TRIPOLI-4, and translation of nuclear heating data for CFD codes Fluent, CFX and structural mechanical software ANSYS Workbench. The coupling approach has been implemented based on SALOME platform with CAD modeling, mesh generation and data visualization capabilities. A novel meshing approach has been developed for generating suitable meshes for MC geometry descriptions. The coupling approach has been concluded to be reliable and efficient after verification calculations of several application cases.

  7. Nonequilibrium molecular dynamics simulation of coupling between nanoparticles and base-fluid in a nanofluid

    International Nuclear Information System (INIS)

    Kang, Hongbo; Zhang, Yuwen; Yang, Mo; Li, Ling

    2012-01-01

    The intent of this study is to examine nonequilibrium heat transfer in a copper–argon nanofluid by molecular dynamics simulation. Two different methods, the physical definition method and the curve fitting method, are introduced to calculate the coupling factor between nanoparticles and base fluid. The results show that the coupling factors obtained by these two methods are consistent. The coupling factor is proportional to the volume fraction of the nanoparticle and inversely proportional to nanoparticle diameter. In the temperature range of 90–200 K, the coupling factor is not affected by temperature. The nanoparticle aggregation results in a decrease of the coupling factor. -- Highlights: ► Nonequilibrium heat transfer in a copper–argon nanofluid is investigated by molecular dynamics simulation. ► The coupling factor is proportion to the volume fraction of the nanoparticle and inverse proportion to nanoparticle diameter. ► In the temperature range of 90–200 K, there is no temperature effect on the coupling factor. ► The nanoparticle aggregation results in a decrease of the coupling factor.

  8. Regio- and stereochemistry of 1,3-dipolar cycloaddition of nitrile oxides to alkenes

    International Nuclear Information System (INIS)

    Litvinovskaya, Raisa P; Khripach, Vladimir A

    2001-01-01

    The published data on the chemistry of intermolecular 1,3-dipolar cycloaddition of nitrile oxides to different types of alkene derivatives are systematised. Various aspects of stereo- and regiochemistry of this reaction are considered. The bibliography includes 182 references.

  9. Structures and dynamics in a two-dimensional dipolar dust particle system

    Science.gov (United States)

    Hou, X. N.; Liu, Y. H.; Kravchenko, O. V.; Lapushkina, T. A.; Azarova, O. A.; Chen, Z. Y.; Huang, F.

    2018-05-01

    The effects of electric dipole moment, the number of dipolar particles, and system temperature on the structures and dynamics of a dipolar dust particle system are studied by molecular dynamics simulations. The results show that the larger electric dipole moment is favorable for the formation of a long-chain structure, the larger number of dipolar dust particles promotes the formation of the multi-chain structure, and the higher system temperature can cause higher rotation frequency. The trajectories, mean square displacement (MSD), and the corresponding spectrum functions of the MSDs are also calculated to illustrate the dynamics of the dipolar dust particle system, which is also closely related to the growth of dust particles. Some simulations are qualitatively in agreement with our experiments and can provide a guide for the study on dust growth, especially on the large-sized particles.

  10. Cluster-cluster aggregation of Ising dipolar particles under thermal noise

    KAUST Repository

    Suzuki, Masaru; Kun, Ferenc; Ito, Nobuyasu

    2009-01-01

    The cluster-cluster aggregation processes of Ising dipolar particles under thermal noise are investigated in the dilute condition. As the temperature increases, changes in the typical structures of clusters are observed from chainlike (D1

  11. Formulation analysis and computation of an optimization-based local-to-nonlocal coupling method.

    Energy Technology Data Exchange (ETDEWEB)

    D' Elia, Marta [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Computing Research; Bochev, Pavel Blagoveston [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Computing Research

    2017-01-01

    In this paper, we present an optimization-based coupling method for local and nonlocal continuum models. Our approach couches the coupling of the models into a control problem where the states are the solutions of the nonlocal and local equations, the objective is to minimize their mismatch on the overlap of the local and nonlocal problem domains, and the virtual controls are the nonlocal volume constraint and the local boundary condition. We present the method in the context of Local-to-Nonlocal di usion coupling. Numerical examples illustrate the theoretical properties of the approach.

  12. Strong coupling and polariton lasing in Te based microcavities embedding (Cd,Zn)Te quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Rousset, J.-G., E-mail: j-g.rousset@fuw.edu.pl; Piętka, B.; Król, M.; Mirek, R.; Lekenta, K.; Szczytko, J.; Borysiuk, J.; Suffczyński, J.; Kazimierczuk, T.; Goryca, M.; Smoleński, T.; Kossacki, P.; Nawrocki, M.; Pacuski, W. [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL-02-093 Warszawa (Poland)

    2015-11-16

    We report on properties of an optical microcavity based on (Cd,Zn,Mg)Te layers and embedding (Cd,Zn)Te quantum wells. The key point of the structure design is the lattice matching of the whole structure to MgTe, which eliminates the internal strain and allows one to embed an arbitrary number of unstrained quantum wells in the microcavity. We evidence the strong light-matter coupling regime already for the structure containing a single quantum well. Embedding four unstrained quantum wells results in further enhancement of the exciton-photon coupling and the polariton lasing in the strong coupling regime.

  13. Optimization of Multiresonant Wireless Power Transfer Network Based on Generalized Coupled Matrix

    Directory of Open Access Journals (Sweden)

    Qiang Zhao

    2017-01-01

    Full Text Available Magnetic coupling resonant wireless power transfer network (MCRWPTN system can realize wireless power transfer for some electrical equipment real-time and high efficiency in a certain spatial scale, which resolves the contradiction between power transfer efficiency and the power transfer distance of the wireless power transfer. A fully coupled resonant energy transfer model for multirelay coils and ports is established. A dynamic adaptive impedance matching control based on fully coupling matrix and particle swarm optimization algorithm based on annealing is developed for the MCRWPTN. Furthermore, as an example, the network which has twenty nodes is analyzed, and the best transmission coefficient which has the highest power transfer efficiency is found using the optimization algorithm, and the coupling constraints are considered simultaneously. Finally, the effectiveness of the proposed method is proved by the simulation results.

  14. Efficient fiber-coupled single-photon sources based on quantum dots

    DEFF Research Database (Denmark)

    Daveau, Raphaël Sura

    refrigeration with coupled quantum wells. Many photonic quantum information processing applications would benet from a highbrightness, ber-coupled source of triggered single photons. This thesis presents a study of such sources based on quantum dots coupled to unidirectional photonic-crystal waveguide devices.......6 %. This latter method opens a promising future for increasing the eciency and reliability of planar chip-based single-photon sources. Refrigeration of a solid-state system with light has potential applications for cooling small-scale electronic and photonic circuits. We show theoretically that two coupled...... semiconductor quantum wells are ecient cooling media because they support long-lived indirect electron-hole pairs. These pairs can be thermally excited to distinct higher-energy states with faster radiative recombination, thereby creating an ecient escape channel to remove thermal energy from the system. From...

  15. History of inductively coupled plasma mass spectrometry-based immunoassays

    International Nuclear Information System (INIS)

    Giesen, Charlotte; Waentig, Larissa; Panne, Ulrich; Jakubowski, Norbert

    2012-01-01

    The analysis of biomolecules requires highly sensitive and selective detection methods capable of tolerating a complex, biological matrix. First applications of biomolecule detection by ICP-MS relied on the use of heteroelements as a label for quantification. However, the combination of immunoassays and ICP-MS facilitates multiparametric analyses through elemental tagging, and provides a powerful alternative to common bioanalytical methods. This approach extends the detection of biomarkers in clinical diagnosis, and has the potential to provide a deeper understanding of the investigated biological system. The results might lead to the detection of diseases at an early stage, or guide treatment plans. Immunoassays are well accepted and established for diagnostic purposes, albeit ICP-MS is scarcely applied for the detection of immune-based assays. However, the screening of biomarkers demands high throughput and multiplex/multiparametric techniques, considering the variety of analytes to be queried. Finally, quantitative information on the expression level of biomarkers is highly desirable to identify abnormalities in a given organism. Thus, it is the aim of this review to introduce the fundamentals, and to discuss the enormous strength of ICP-MS for the detection of different immunoassays on the basis of selected applications, with a special focus on LA‐ICP‐MS. - Highlights: ► We discuss the fundamentals of elemental tagging for ICP‐MS applications. ► We propose a definition for the expressions “label” and “tag”. ► We highlight LA‐ICP‐MS‐based heteroelement detection. ► We give an historic overview on ICP-MS and LA‐ICP‐MS-based immunoassays. ► In a personal outlook, we discuss future improvements realistically attainable.

  16. The phase transition in the anisotropic Heisenberg model with long range dipolar interactions

    International Nuclear Information System (INIS)

    Mól, L.A.S.; Costa, B.V.

    2014-01-01

    In this work we have used extensive Monte Carlo calculations to study the planar to paramagnetic phase transition in the two-dimensional anisotropic Heisenberg model with dipolar interactions (AHd) considering the true long-range character of the dipolar interactions by means of the Ewald summation. Our results are consistent with an order–disorder phase transition with unusual critical exponents in agreement with our previous results for the Planar Rotator model with dipolar interactions. Nevertheless, our results disagree with the Renormalization Group results of Maier and Schwabl [Phys. Rev. B, 70, 134430 (2004)] [13] and the results of Rapini et al. [Phys. Rev. B, 75, 014425 (2007)] [12], where the AHd was studied using a cut-off in the evaluation of the dipolar interactions. We argue that besides the long-range character of dipolar interactions their anisotropic character may have a deeper effect in the system than previously believed. Besides, our results show that the use of a cut-off radius in the evaluation of dipolar interactions must be avoided when analyzing the critical behavior of magnetic systems, since it may lead to erroneous results. - Highlights: • The anisotropic Heisenberg model with dipolar interactions is studied. • True long-range interactions were considered by means of Ewald summation. • We found an order–disorder phase transition with unusual critical exponents. • Previous results show a different behavior when a cut-off radius is introduced. • The use of a cut-off radius must be avoided when dealing with dipolar systems

  17. Statistical mechanics of molecular fluids. The RHNC theory applied to hard dipolar spheres

    International Nuclear Information System (INIS)

    Lombardero, M.; Lado, F.; Abascal, J.L.F.; Lago, S.; Enciso, E.

    1988-01-01

    The RHNC (reference hipernetted chain) equation, together with an optimization criterion which extremalizes the Helmholtz free energy, is used to obtain structural, thermodynamic, and dielectric properties of a system made up of hard dipolar spheres. The comparison with simulation results is made in the same boundary conditions and then the properties of an infinite system are evaluated for a variaty of states at different densities and dipolar moments. (Author)

  18. Energetic electron injections and dipolarization events in Mercury's magnetotail: Substorm dynamics

    Science.gov (United States)

    Dewey, R. M.; Slavin, J. A.; Raines, J. M.; Imber, S.; Baker, D. N.; Lawrence, D. J.

    2017-12-01

    Despite its small size, Mercury's terrestrial-like magnetosphere experiences brief, yet intense, substorm intervals characterized by features similar to at Earth: loading/unloading of the tail lobes with open magnetic flux, dipolarization of the magnetic field at the inner edge of the plasma sheet, and, the focus of this presentation, energetic electron injection. We use the Gamma-Ray Spectrometer's high-time resolution (10 ms) energetic electron measurements to determine the relationship between substorm activity and energetic electron injections coincident with dipolarization fronts in the magnetotail. These dipolarizations were detected on the basis of their rapid ( 2 s) increase in the northward component of the tail magnetic field (ΔBz 30 nT), which typically persists for 10 s. We estimate the typical flow channel to be 0.15 RM, planetary convection speed of 750 km/s, cross-tail potential drop of 7 kV, and flux transport of 0.08 MWb for each dipolarization event, suggesting multiple simultaneous and sequential dipolarizations are required to unload the >1 MWb of magnetic flux typically returned to the dayside magnetosphere during a substorm interval. Indeed, while we observe most dipolarization-injections to be isolated or in small chains of events (i.e., 1-3 events), intervals of sawtooth-like injections with >20 sequential events are also present. The typical separation between dipolarization-injection events is 10 s. Magnetotail dipolarization, in addition to being a powerful source of electron acceleration, also plays a significant role in the substorm process at Mercury.

  19. Stable integrated hyper-parametric oscillator based on coupled optical microcavities.

    Science.gov (United States)

    Armaroli, Andrea; Feron, Patrice; Dumeige, Yannick

    2015-12-01

    We propose a flexible scheme based on three coupled optical microcavities that permits us to achieve stable oscillations in the microwave range, the frequency of which depends only on the cavity coupling rates. We find that the different dynamical regimes (soft and hard excitation) affect the oscillation intensity, but not their periods. This configuration may permit us to implement compact hyper-parametric sources on an integrated optical circuit with interesting applications in communications, sensing, and metrology.

  20. Microscopic theory of the Coulomb based exchange coupling in magnetic tunnel junctions.

    Science.gov (United States)

    Udalov, O G; Beloborodov, I S

    2017-05-04

    We study interlayer exchange coupling based on the many-body Coulomb interaction between conduction electrons in magnetic tunnel junction. This mechanism complements the known interaction between magnetic layers based on virtual electron hopping (or spin currents). We find that these two mechanisms have different behavior on system parameters. The Coulomb based coupling may exceed the hopping based exchange. We show that the Coulomb based exchange interaction, in contrast to the hopping based coupling, depends strongly on the dielectric constant of the insulating layer. The dependence of the interlayer exchange interaction on the dielectric properties of the insulating layer in magnetic tunnel junction is similar to magneto-electric effect where electric and magnetic degrees of freedom are coupled. We calculate the interlayer coupling as a function of temperature and electric field for magnetic tunnel junction with ferroelectric layer and show that the exchange interaction between magnetic leads has a sharp decrease in the vicinity of the ferroelectric phase transition and varies strongly with external electric field.

  1. Reliability Coupled Sensitivity Based Design Approach for Gravity Retaining Walls

    Science.gov (United States)

    Guha Ray, A.; Baidya, D. K.

    2012-09-01

    Sensitivity analysis involving different random variables and different potential failure modes of a gravity retaining wall focuses on the fact that high sensitivity of a particular variable on a particular mode of failure does not necessarily imply a remarkable contribution to the overall failure probability. The present paper aims at identifying a probabilistic risk factor ( R f ) for each random variable based on the combined effects of failure probability ( P f ) of each mode of failure of a gravity retaining wall and sensitivity of each of the random variables on these failure modes. P f is calculated by Monte Carlo simulation and sensitivity analysis of each random variable is carried out by F-test analysis. The structure, redesigned by modifying the original random variables with the risk factors, is safe against all the variations of random variables. It is observed that R f for friction angle of backfill soil ( φ 1 ) increases and cohesion of foundation soil ( c 2 ) decreases with an increase of variation of φ 1 , while R f for unit weights ( γ 1 and γ 2 ) for both soil and friction angle of foundation soil ( φ 2 ) remains almost constant for variation of soil properties. The results compared well with some of the existing deterministic and probabilistic methods and found to be cost-effective. It is seen that if variation of φ 1 remains within 5 %, significant reduction in cross-sectional area can be achieved. But if the variation is more than 7-8 %, the structure needs to be modified. Finally design guidelines for different wall dimensions, based on the present approach, are proposed.

  2. Modeling liquid-vapor equilibria with an equation of state taking into account dipolar interactions and association by hydrogen bonding

    International Nuclear Information System (INIS)

    Perfetti, E.

    2006-11-01

    Modelling fluid-rock interactions as well as mixing and unmixing phenomena in geological processes requires robust equations of state (EOS) which must be applicable to systems containing water, gases over a broad range of temperatures and pressures. Cubic equations of state based on the Van der Waals theory (e. g. Soave-Redlich-Kwong or Peng-Robinson) allow simple modelling from the critical parameters of the studied fluid components. However, the accuracy of such equations becomes poor when water is a major component of the fluid since neither association trough hydrogen bonding nor dipolar interactions are accounted for. The Helmholtz energy of a fluid may be written as the sum of different energetic contributions by factorization of partition function. The model developed in this thesis for the pure H 2 O and H 2 S considers three contributions. The first contribution represents the reference Van der Waals fluid which is modelled by the SRK cubic EOS. The second contribution accounts for association through hydrogen bonding and is modelled by a term derived from Cubic Plus Association (CPA) theory. The third contribution corresponds to the dipolar interactions and is modelled by the Mean Spherical Approximation (MSA) theory. The resulting CPAMSA equation has six adjustable parameters, which three represent physical terms whose values are close to their experimental counterpart. This equation results in a better reproduction of the thermodynamic properties of pure water than obtained using the classical CPA equation along the vapour-liquid equilibrium. In addition, extrapolation to higher temperatures and pressure is satisfactory. Similarly, taking into account dipolar interactions together with the SRK cubic equation of state for calculating molar volume of H 2 S as a function of pressure and temperature results in a significant improvement compared to the SRK equation alone. Simple mixing rules between dipolar molecules are proposed to model the H 2 O-H 2 S

  3. Effects of a Randomized Couple-Based Intervention on Quality of Life of Breast Cancer Patients and Their Partners

    Science.gov (United States)

    Kayser, Karen; Feldman, Barry N.; Borstelmann, Nancy A.; Daniels, Ann A.

    2010-01-01

    The purpose of this study was to determine the effectiveness of a couple-based intervention on the quality of life (QOL) of early-stage breast cancer patients and their partners. A randomized controlled design was used to assign couples to either the hospital standard social work services (SSWS) or a couple-based intervention, the Partners in…

  4. The Effects of a Couples-Based Health Behavior Intervention During Pregnancy on Latino Couples' Dyadic Satisfaction Postpartum.

    Science.gov (United States)

    Coop Gordon, Kristina; Roberson, Patricia N E; Hughes, Jessica A; Khaddouma, Alexander M; Swamy, Geeta K; Noonan, Devon; Gonzalez, Alicia M; Fish, Laura; Pollak, Kathryn I

    2018-03-30

    Many couples tend to report steadily decreasing relationship quality following the birth of a child. However, little is known about the postpartum period for Latino couples, a rapidly growing ethnic group who are notably underserved by mental and physical health caregivers in the United States. Thus, this study investigated whether a brief couples' intervention focused on helping couples support each other while increasing healthy behaviors might improve dyadic functioning postpartum. This study presents secondary analyses of data regarding couple functioning from a larger randomized controlled trial with 348 Latino couples to promote smoking cessation. Portions of the intervention taught the couple communication and problem-solving skills to increase healthy behavior. Couples participated in four face-to-face assessments across 1 year starting at the end of the first trimester. Latent growth curve analyses revealed that the treatment group reported an increase in relationship satisfaction and constructive communication after the intervention, which diminished by 1-year follow-up, returning couples to their baseline levels of satisfaction. Results suggest that incorporating a brief couple intervention as part of a larger health intervention for Latinos may prevent postpartum decreases in relationship satisfaction. © 2018 Family Process Institute.

  5. Classical and quantum phases of low-dimensional dipolar systems

    Energy Technology Data Exchange (ETDEWEB)

    Cartarius, Florian

    2016-09-22

    In this thesis we present a detailed study of the phase diagram of ultracold bosonic atoms confined along a tight atomic wave guide, along which they experience an optical lattice potential. In this quasi-one dimensional model we analyse the interplay between interactions and quantum fluctuations in (i) determining the non-equilibrium steady state after a quench and (ii) giving rise to novel equilibrium phases, when the interactions combine the s-wave contact interaction and the anisotropic long range dipole-dipole interactions. In detail, in the first part of the thesis we study the depinning of a gas of impenetrable bosons following the sudden switch of of the optical lattice. By means of a Bose-Fermi mapping we infer the exact quantum dynamical evolution and show that in the thermodynamic limit the system is in a non-equilibrium steady state without quasi-long range order. In the second part of the thesis, we study the effect of quantum fluctuations on the linear-zigzag instability in the ground state of ultracold dipolar bosons, as a function of the strength of the transverse confinement. We first analyse the linear-zigzag instability in the classical regime, and then use our results to develop a multi-mode Bose-Hubbard model for the system. We then develop several numerical methods, to determine the ground state.

  6. Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

    2012-01-01

    Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

  7. Optimization design of wireless charging system for autonomous robots based on magnetic resonance coupling

    Directory of Open Access Journals (Sweden)

    Junhua Wang

    2018-05-01

    Full Text Available Wireless charging is the key technology to realize real autonomy of mobile robots. As the core part of wireless power transfer system, coupling mechanism including coupling coils and compensation topology is analyzed and optimized through simulations, to achieve stable and practical wireless charging suitable for ordinary robots. Multi-layer coil structure, especially double-layer coil is explored and selected to greatly enhance coupling performance, while shape of ferrite shielding goes through distributed optimization to guarantee coil fault tolerance and cost effectiveness. On the basis of optimized coils, primary compensation topology is analyzed to adopt composite LCL compensation, to stabilize operations of the primary side under variations of mutual inductance. Experimental results show the optimized system does make sense for wireless charging application for robots based on magnetic resonance coupling, to realize long-term autonomy of robots.

  8. On the Nonlinear Behavior of the Piezoelectric Coupling on Vibration-Based Energy Harvesters

    Directory of Open Access Journals (Sweden)

    Luciana L. Silva

    2015-01-01

    Full Text Available Vibration-based energy harvesting with piezoelectric elements has an increasing importance nowadays being related to numerous potential applications. A wide range of nonlinear effects is observed in energy harvesting devices and the analysis of the power generated suggests that they have considerable influence on the results. Linear constitutive models for piezoelectric materials can provide inconsistencies on the prediction of the power output of the energy harvester, mainly close to resonant conditions. This paper investigates the effect of the nonlinear behavior of the piezoelectric coupling. A one-degree of freedom mechanical system is coupled to an electrical circuit by a piezoelectric element and different coupling models are investigated. Experimental tests available in the literature are employed as a reference establishing the best matches of the models. Subsequently, numerical simulations are carried out showing different responses of the system indicating that nonlinear piezoelectric couplings can strongly modify the system dynamics.

  9. Coupled incompressible Smoothed Particle Hydrodynamics model for continuum-based modelling sediment transport

    Science.gov (United States)

    Pahar, Gourabananda; Dhar, Anirban

    2017-04-01

    A coupled solenoidal Incompressible Smoothed Particle Hydrodynamics (ISPH) model is presented for simulation of sediment displacement in erodible bed. The coupled framework consists of two separate incompressible modules: (a) granular module, (b) fluid module. The granular module considers a friction based rheology model to calculate deviatoric stress components from pressure. The module is validated for Bagnold flow profile and two standardized test cases of sediment avalanching. The fluid module resolves fluid flow inside and outside porous domain. An interaction force pair containing fluid pressure, viscous term and drag force acts as a bridge between two different flow modules. The coupled model is validated against three dambreak flow cases with different initial conditions of movable bed. The simulated results are in good agreement with experimental data. A demonstrative case considering effect of granular column failure under full/partial submergence highlights the capability of the coupled model for application in generalized scenario.

  10. Optimization design of wireless charging system for autonomous robots based on magnetic resonance coupling

    Science.gov (United States)

    Wang, Junhua; Hu, Meilin; Cai, Changsong; Lin, Zhongzheng; Li, Liang; Fang, Zhijian

    2018-05-01

    Wireless charging is the key technology to realize real autonomy of mobile robots. As the core part of wireless power transfer system, coupling mechanism including coupling coils and compensation topology is analyzed and optimized through simulations, to achieve stable and practical wireless charging suitable for ordinary robots. Multi-layer coil structure, especially double-layer coil is explored and selected to greatly enhance coupling performance, while shape of ferrite shielding goes through distributed optimization to guarantee coil fault tolerance and cost effectiveness. On the basis of optimized coils, primary compensation topology is analyzed to adopt composite LCL compensation, to stabilize operations of the primary side under variations of mutual inductance. Experimental results show the optimized system does make sense for wireless charging application for robots based on magnetic resonance coupling, to realize long-term autonomy of robots.

  11. Research on the Diagnosis of Rotor Coupling Fault Based on Wavelet Packet and Local Fisher Discriminant

    Directory of Open Access Journals (Sweden)

    Guangbin Wang

    2014-09-01

    Full Text Available this article is for the coupling fault diagnosis of rotor system, and does in-depth analysis of the rotor unbalance and misalignment, and the fault formed by the coupling of these two. Through research, Rotor Coupling was found filled with rich features. In this paper, Wavelet packet de- noising ideas being introduced to the local Fisher discriminant analysis (LFDA, a new method of fault diagnosis based on Wavelet Packet and Local Fisher Discriminant is proposed. The technology of information fusion is applied to the data processing with coupling faults. By comparing and analyzing the algorithms effect of LE, LPP, FDA, LFDA and IOLFA through experiment, it shows that LE and LPP are unable to identify the fault, while FDA, LFDA has better identification, and Wavelet Packet and Local Fisher discriminant has the best effect.

  12. Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators

    Science.gov (United States)

    Velichko, Andrey; Belyaev, Maksim; Putrolaynen, Vadim; Perminov, Valentin; Pergament, Alexander

    2018-03-01

    We explore a prototype of an oscillatory neural network (ONN) based on vanadium dioxide switching devices. The model system under study represents two oscillators based on thermally coupled VO2 switches. Numerical simulation shows that the effective action radius RTC of coupling depends both on the total energy released during switching and on the average power. It is experimentally and numerically proved that the temperature change ΔT commences almost synchronously with the released power peak and T-coupling reveals itself up to a frequency of about 10 kHz. For the studied switching structure configuration, the RTC value varies over a wide range from 4 to 45 μm, depending on the external circuit capacitance C and resistance Ri, but the variation of Ri is more promising from the practical viewpoint. In the case of a "weak" coupling, synchronization is accompanied by attraction effect and decrease of the main spectra harmonics width. In the case of a "strong" coupling, the number of effects increases, synchronization can occur on subharmonics resulting in multilevel stable synchronization of two oscillators. An advanced algorithm for synchronization efficiency and subharmonic ratio calculation is proposed. It is shown that of the two oscillators the leading one is that with a higher main frequency, and, in addition, the frequency stabilization effect is observed. Also, in the case of a strong thermal coupling, the limit of the supply current parameters, for which the oscillations exist, expands by ∼10%. The obtained results have a universal character and open up a new kind of coupling in ONNs, namely, T-coupling, which allows for easy transition from 2D to 3D integration. The effect of subharmonic synchronization hold promise for application in classification and pattern recognition.

  13. The magnetoelectric coupling effect in multiferroic composites based on PZT–ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowska, J.A., E-mail: joanna.bartkowska@us.edu.pl

    2015-01-15

    In the multiferroic materials, the dielectric and magnetic properties are closely correlated through the coupling interaction between the ferroelectric and magnetic order. We attempted to determine the values of magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the ferroelectric–ferromagnetic composite PZT–ferrite type, namely PSZTC–NiZn and PBZTN–NiZn. The main component of the ferroelectric–ferromagnetic composite was PZT type powder (with ferroelectric properties), which was synthesized using sintering of a mixture of simple oxides in solid phase. The second element of the ferroelectric–ferromagnetic composite was the ferrite powder (with ferromagnetic properties). Ferrite powder was synthesized using calcination. Next, the mixed components were synthesized using sintering of the mixture of simple oxides in a solid phase (compaction by a free sintering method). The temperature dependences of the dielectric permittivity (ε) for the different frequencies and for both multiferroic composites were investigated. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified. - Highlights: • The magnetoelectric effect at two different ferroelectric–ferromagnetic composites based on a PZT and nickel–zinc ferrite. • Multiferroics composite incorporate both ferroelectric and magnetic phases. • The mechanism of the magnetoelectric coupling between ferroelectric and magnetic properties, in multiferroic composites, is caused by the strain. • The determination of the magnetoelectric coupling coefficient based on a theoretical model and the measurements of dielectric permittivity.

  14. The magnetoelectric coupling effect in multiferroic composites based on PZT–ferrite

    International Nuclear Information System (INIS)

    Bartkowska, J.A.

    2015-01-01

    In the multiferroic materials, the dielectric and magnetic properties are closely correlated through the coupling interaction between the ferroelectric and magnetic order. We attempted to determine the values of magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the ferroelectric–ferromagnetic composite PZT–ferrite type, namely PSZTC–NiZn and PBZTN–NiZn. The main component of the ferroelectric–ferromagnetic composite was PZT type powder (with ferroelectric properties), which was synthesized using sintering of a mixture of simple oxides in solid phase. The second element of the ferroelectric–ferromagnetic composite was the ferrite powder (with ferromagnetic properties). Ferrite powder was synthesized using calcination. Next, the mixed components were synthesized using sintering of the mixture of simple oxides in a solid phase (compaction by a free sintering method). The temperature dependences of the dielectric permittivity (ε) for the different frequencies and for both multiferroic composites were investigated. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified. - Highlights: • The magnetoelectric effect at two different ferroelectric–ferromagnetic composites based on a PZT and nickel–zinc ferrite. • Multiferroics composite incorporate both ferroelectric and magnetic phases. • The mechanism of the magnetoelectric coupling between ferroelectric and magnetic properties, in multiferroic composites, is caused by the strain. • The determination of the magnetoelectric coupling coefficient based on a theoretical model and the measurements of dielectric permittivity

  15. Developing confidence in a coupled TH model based on the results of experiment by using engineering scale test facility, 'COUPLE'

    International Nuclear Information System (INIS)

    Fujisaki, Kiyoshi; Suzuki, Hideaki; Fujita, Tomoo

    2008-03-01

    It is necessary to understand quantitative changes of near-field conditions and processes over time and space for modeling the near-field evolution after emplacement of engineered barriers. However, the coupled phenomena in near-field are complicated because thermo-, hydro-, mechanical, chemical processes will interact each other. The question is, therefore, whether the applied model will represent the coupled behavior adequately or not. In order to develop confidence in the modeling, it is necessary to compare with results of coupled behavior experiments in laboratory or in site. In this report, we evaluated the applicability of a coupled T-H model under the conditions of simulated near-field for the results of coupled T-H experiment in laboratory. As a result, it has been shown that the fitting by the modeling with the measured data is reasonable under this condition. (author)

  16. Ultrafast responses of dipolar and V-shaped dipicolinate derivatives with potential applications in the labeling of biomolecules

    Science.gov (United States)

    Wang, Yaochuan; Liu, Siyuan; Liu, Dajun; Wang, Guiqiu; Xiao, Haibo

    2016-02-01

    A dipolar dipicolinate derivative, trans-dimethyl-4-[4'-(N,N-diphenylamino)-styry1]-pyridin-2,6-dicarboxylate (P-1), and a P-1based V-shaped compound, {4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl) vinyl]}-N-phenyl-N-{4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl)vinylphenyl]}aniline (P-2), with intense two-photon fluorescence emission properties were systematically investigated by using steady-state absorption and fluorescence spectroscopy, open-aperture Z-scans, and two-photon excited fluorescence (TPF). The two-photon absorption cross-section of the V-shaped compound P-2 in tetrahydrofuran (THF) was determined to be 208 GM, which represents a 6.5-fold enhancement compared with its dipolar counterpart P-1 (32 GM). Extension of the intramolecular charge transfer (ICT) in the V-shaped dipicolinate derivative has been suggested as the mechanism of enhancement. The excited state dynamics from transient absorption spectroscopy were analyzed and discussed. The formation and relaxation lifetimes of the ICT state for these dipicolinate derivatives in THF solutions were found to be several picoseconds and several hundred picoseconds, respectively. The results show an increased ICT character of the V-shaped compound and a potential application for this compound in two-photon fluorescence imaging fields.

  17. Ultrafast responses of dipolar and V-shaped dipicolinate derivatives with potential applications in the labeling of biomolecules

    Directory of Open Access Journals (Sweden)

    Yaochuan Wang

    2016-02-01

    Full Text Available A dipolar dipicolinate derivative, trans-dimethyl-4-[4′-(N,N-diphenylamino-styry1]-pyridin-2,6-dicarboxylate (P-1, and a P-1based V-shaped compound, {4-[(E-2-(2,6-dimethoxycarbonylpyridin-4-yl vinyl]}-N-phenyl-N-{4-[(E-2-(2,6-dimethoxycarbonylpyridin-4-ylvinylphenyl]}aniline (P-2, with intense two-photon fluorescence emission properties were systematically investigated by using steady-state absorption and fluorescence spectroscopy, open-aperture Z-scans, and two-photon excited fluorescence (TPF. The two-photon absorption cross-section of the V-shaped compound P-2 in tetrahydrofuran (THF was determined to be 208 GM, which represents a 6.5-fold enhancement compared with its dipolar counterpart P-1 (32 GM. Extension of the intramolecular charge transfer (ICT in the V-shaped dipicolinate derivative has been suggested as the mechanism of enhancement. The excited state dynamics from transient absorption spectroscopy were analyzed and discussed. The formation and relaxation lifetimes of the ICT state for these dipicolinate derivatives in THF solutions were found to be several picoseconds and several hundred picoseconds, respectively. The results show an increased ICT character of the V-shaped compound and a potential application for this compound in two-photon fluorescence imaging fields.

  18. A global hybrid coupled model based on atmosphere-SST feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Cimatoribus, Andrea A.; Drijfhout, Sybren S. [Royal Netherlands Meteorological Institute, De Bilt (Netherlands); Dijkstra, Henk A. [Utrecht University, Institute for Marine and Atmospheric Research Utrecht, Utrecht (Netherlands)

    2012-02-15

    A global hybrid coupled model is developed, with the aim of studying the effects of ocean-atmosphere feedbacks on the stability of the Atlantic meridional overturning circulation. The model includes a global ocean general circulation model and a statistical atmosphere model. The statistical atmosphere model is based on linear regressions of data from a fully coupled climate model on sea surface temperature both locally and hemispherically averaged, being the footprint of Atlantic meridional overturning variability. It provides dynamic boundary conditions to the ocean model for heat, freshwater and wind-stress. A basic but consistent representation of ocean-atmosphere feedbacks is captured in the hybrid coupled model and it is more than 10 times faster than the fully coupled climate model. The hybrid coupled model reaches a steady state with a climate close to the one of the fully coupled climate model, and the two models also have a similar response (collapse) of the Atlantic meridional overturning circulation to a freshwater hosing applied in the northern North Atlantic. (orig.)

  19. Interference coupling analysis based on a hybrid method: application to a radio telescope system

    Science.gov (United States)

    Xu, Qing-Lin; Qiu, Yang; Tian, Jin; Liu, Qi

    2018-02-01

    Working in a way that passively receives electromagnetic radiation from a celestial body, a radio telescope can be easily disturbed by external radio frequency interference as well as electromagnetic interference generated by electric and electronic components operating at the telescope site. A quantitative analysis of these interferences must be taken into account carefully for further electromagnetic protection of the radio telescope. In this paper, based on electromagnetic topology theory, a hybrid method that combines the Baum-Liu-Tesche (BLT) equation and transfer function is proposed. In this method, the coupling path of the radio telescope is divided into strong coupling and weak coupling sub-paths, and the coupling intensity criterion is proposed by analyzing the conditions in which the BLT equation simplifies to a transfer function. According to the coupling intensity criterion, the topological model of a typical radio telescope system is established. The proposed method is used to solve the interference response of the radio telescope system by analyzing subsystems with different coupling modes separately and then integrating the responses of the subsystems as the response of the entire system. The validity of the proposed method is verified numerically. The results indicate that the proposed method, compared with the direct solving method, reduces the difficulty and improves the efficiency of interference prediction.

  20. Physics of Substorm Growth Phase, Onset, and Dipolarization

    Energy Technology Data Exchange (ETDEWEB)

    C.Z. Cheng

    2003-10-22

    A new scenario of substorm growth phase, onset, and depolarization during expansion phase and the corresponding physical processes are presented. During the growth phase, as a result of enhanced plasma convection, the plasma pressure and its gradient are continued to be enhanced over the quiet-time values in the plasma sheet. Toward the late growth phase, a strong cross-tail current sheet is formed in the near-Earth plasma sheet region, where a local magnetic well is formed, the plasma beta can reach a local maximum with value larger than 50 and the cross-tail current density can be enhanced to over 10nA/m{sup 2} as obtained from 3D quasi-static magnetospheric equilibrium solutions for the growth phase. The most unstable kinetic ballooning instabilities (KBI) are expected to be located in the tailward side of the strong cross-tail current sheet region. The field lines in the most unstable KBI region map to the transition region between the region-1 and region-2 currents in the ionosphere, which is consistent with the observed initial brightening location of the breakup arc in the intense proton precipitation region. The KBI explains the AMPTE/CCE observations that a low-frequency instability with a wave period of 50-75 seconds is excited about 2-3 minutes prior to substorm onset and grows exponentially to a large amplitude at the onset of current disruption (or current reduction). At the current disruption onset higher frequency instabilities are excited so that the plasma and electromagnetic field fluctuations form a strong turbulent state. Plasma transport takes place due to the strong turbulence to relax the ambient plasma pressure profile so that the plasma pressure and current density are reduced and the ambient magnetic field intensity increases by more than a factor of 2 in the high-beta(sub)eq region and the field line geometry recovers from tail-like to dipole-like dipolarization.

  1. Physics of Substorm Growth Phase, Onset, and Dipolarization

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    2003-01-01

    A new scenario of substorm growth phase, onset, and depolarization during expansion phase and the corresponding physical processes are presented. During the growth phase, as a result of enhanced plasma convection, the plasma pressure and its gradient are continued to be enhanced over the quiet-time values in the plasma sheet. Toward the late growth phase, a strong cross-tail current sheet is formed in the near-Earth plasma sheet region, where a local magnetic well is formed, the plasma beta can reach a local maximum with value larger than 50 and the cross-tail current density can be enhanced to over 10nA/m 2 as obtained from 3D quasi-static magnetospheric equilibrium solutions for the growth phase. The most unstable kinetic ballooning instabilities (KBI) are expected to be located in the tailward side of the strong cross-tail current sheet region. The field lines in the most unstable KBI region map to the transition region between the region-1 and region-2 currents in the ionosphere, which is consistent with the observed initial brightening location of the breakup arc in the intense proton precipitation region. The KBI explains the AMPTE/CCE observations that a low-frequency instability with a wave period of 50-75 seconds is excited about 2-3 minutes prior to substorm onset and grows exponentially to a large amplitude at the onset of current disruption (or current reduction). At the current disruption onset higher frequency instabilities are excited so that the plasma and electromagnetic field fluctuations form a strong turbulent state. Plasma transport takes place due to the strong turbulence to relax the ambient plasma pressure profile so that the plasma pressure and current density are reduced and the ambient magnetic field intensity increases by more than a factor of 2 in the high-beta(sub)eq region and the field line geometry recovers from tail-like to dipole-like dipolarization

  2. Analyzing Sexual Health-Related Beliefs Among Couples in Marriage Based on the Health Belief Model

    Directory of Open Access Journals (Sweden)

    Majid Barati

    2014-06-01

    Full Text Available Introduction: Sexual health is the integrity between mind, emotions, and body, and any disorder leading to discoordination, can be associated with sexual dysfunction. The aim of this study was to investigate the beliefs of couples attending marriage counseling centers toward sexual health based on the health belief model. Materials and Methods: This cross sectional descriptive study was performed on 400 couples referring to marriage counseling centers of Hamadan recruited with a random sampling method. The participants completed a self-administered questionnaire including demographic characteristics, knowledge and health belief model constructs. Data analysis was performed using SPSS-16 software, by Pearson’s coefficient correlation, independent T-test, and one-way ANOVA. Results: Couples had a moderate knowledge of sexual health. In addition, perceived susceptibility and severity of the consequences of unsafe sexual behavior among couples were not satisfactory however, perceived benefits and barriers were reported in a relatively good level. Internet and friends were the most important sources for sexual health information. Conclusion: Promoting knowledge and beliefs toward sexual health by preparing training packages based on the needs of couples and removing obstacles to have normal sexual behavior are necessary.

  3. Coupling of HDPE/hydroxyapatite composites by silane-based methodologies.

    Science.gov (United States)

    Sousa, R A; Reis, R L; Cunha, A M; Bevis, M J

    2003-06-01

    Several coupling treatments based on silane chemicals were investigated for the development of high density (HDPE)/hydroxyapatite (HA) composites. Two HA powders, sintered HA (HAs) and non sintered HA (HAns), were studied in combination with five silanes, namely y-methacryloxy propyltrimethoxy silane (MEMO), 3-(2-aminoethyl)aminopropyltrimethoxy silane (DAMO), vinyltrimethoxy silane (VTMO), 3-aminopropyltriethoxy silane (AMEO) and trimethoxypropyl silane (PTMO). The HA particles were treated by a dipping in method or by spraying with silane solutions. After drying, the treated powders were compounded with HDPE or HDPE with acrylic acid and/or organic peroxide and subsequently compression molded. The tensile test specimens obtained from the molded plates were tensile tested and their fracture surfaces were observed by scanning electron microscopy (SEM). For the sintered HA (HAs) composites, the most effective coupling treatments concerning stiffness are those based on MEMO and AMEO. The low influence of these coupling procedures on strength is believed to be associated to the low volume fraction and the relatively smooth surface of the used HA particles. For the non-sintered HA (HAns) composites, it was possible to improve significantly both the stiffness and the strength. Amino silanes demonstrated to be highly efficient concerning strength enhancement. The higher effectiveness of the coupling treatments for HAns filled composites is attributed to their higher particle surface area, smaller particle size distribution and expected higher chemical reactivity. For both cases, the improvement in mechanical performance after the coupling treatment is consistent with the enhancement in interfacial adhesion observed by SEM.

  4. Van-der-Waals interaction of atoms in dipolar Rydberg states

    Science.gov (United States)

    Kamenski, Aleksandr A.; Mokhnenko, Sergey N.; Ovsiannikov, Vitaly D.

    2018-02-01

    An asymptotic expression for the van-der-Waals constant C 6( n) ≈ -0.03 n 12 K p ( x) is derived for the long-range interaction between two highly excited hydrogen atoms A and B in their extreme Stark states of equal principal quantum numbers n A = n B = n ≫ 1 and parabolic quantum numbers n 1(2) = n - 1, n 2(1) = m = 0 in the case of collinear orientation of the Stark-state dipolar electric moments and the interatomic axis. The cubic polynomial K 3( x) in powers of reciprocal values of the principal quantum number x = 1/ n and quadratic polynomial K 2( y) in powers of reciprocal values of the principal quantum number squared y = 1/ n 2 were determined on the basis of the standard curve fitting polynomial procedure from the calculated data for C 6( n). The transformation of attractive van-der-Waals force ( C 6 > 0) for low-energy states n < 23 into repulsive force ( C 6 < 0) for all higher-energy states of n ≥ 23, is observed from the results of numerical calculations based on the second-order perturbation theory for the operator of the long-range interaction between neutral atoms. This transformation is taken into account in the asymptotic formulas (in both cases of p = 2, 3) by polynomials K p tending to unity at n → ∞ ( K p (0) = 1). The transformation from low- n attractive van-der-Waals force into high- n repulsive force demonstrates the gradual increase of the negative contribution to C 6( n) from the lower-energy two-atomic states, of the A(B)-atom principal quantum numbers n'A(B) = n-Δ n (where Δ n = 1, 2, … is significantly smaller than n for the terms providing major contribution to the second-order series), which together with the states of n″B(A) = n+Δ n make the joint contribution proportional to n 12. So, the hydrogen-like manifold structure of the energy spectrum is responsible for the transformation of the power-11 asymptotic dependence C 6( n) ∝ n 11of the low-angular-momenta Rydberg states in many-electron atoms into the power

  5. Coupling analysis of wind turbine blades based on aeroelastics and aerodynsmics

    DEFF Research Database (Denmark)

    Wang, Xudong; Chen, Jin; Zhang, Shigiang

    2010-01-01

    The structural dynamic equations of blades were constructed for blades of wind turbines. The vibration velocity of blades and the relative flow velocity were calculated using the structural dynamics model. Based on the BEM (Blade Element Momentum) theory and traditional areodynamics, the coupling...

  6. Lattice Boltzmann based multicomponent reactive transport model coupled with geochemical solver for scale simulations

    NARCIS (Netherlands)

    Patel, R.A.; Perko, J.; Jaques, D.; De Schutter, G.; Ye, G.; Van Breugel, K.

    2013-01-01

    A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multi-component transport model is then coupled with the

  7. Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

    NARCIS (Netherlands)

    Bruni, S.; Llombart Juan, N.; Neto, A.; Gerini, G.; Maci, S.

    2004-01-01

    A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total

  8. The structure of the interface in the solvent mediated interaction of dipolar surfaces

    International Nuclear Information System (INIS)

    Dzhavakhidze, P.G.; Levadny, V.G.

    1987-08-01

    Interaction of two dipolar surfaces separated by a polar medium is considered within the framework of nonlocal electrostatics. The dipolar surface layers are modelled as regular lattices with fixed orientation of dipoles which are immersed into the solvent; solvent response is characterized by nonlocal dielectric function. The model is elaborated in order to reveal the role of the dipolar layer discreteness in the electric field produced by one surface and the interaction between two surfaces (which gives rise to the so called ''hydration'' or ''structural'' force acting between mineral surfaces and phospholipid bilayers). The discreteness effects are present only for commensurate lattices. Their special mutual arrangement then may lead to considerable reduction of structural forces, viz. the usual repulsion regime may change at short distances to attraction. Conditions are considered when repulsion is entirely replaced by attraction, i.e. the ''hydration barrier'' disappears. In appended note we discuss the role of solvation of surface dipolar groups. We propose an explanation of why two modes of decay (one with oscillative fine structure) may be present in the dependence of the force upon distance if the surface dipolar groups are immersed deep enough in the solvent and how the long-range oscillative mode disappears when the surface is but weakly solvated. (author). 35 refs, 5 figs

  9. Fiber-optic coupling based on nonimaging expanded-beam optics.

    Science.gov (United States)

    Moslehi, B; Ng, J; Kasimoff, I; Jannson, T

    1989-12-01

    We have fabricated and experimentally tested low-cost and mass-producible multimode fiber-optic couplers and connectors based on nonimaging beam-expanding optics and Liouville's theorem. Analysis indicates that a pair coupling loss of -0.25 dB can be achieved. Experimentally, we measured insertion losses as low as -0.38 dB. The beam expanders can be mass produced owing to the use of plastic injection-molding fabrication techniques and packaged in standard connector housings. This design is compatible with the fiber geometry and can yield highly stable coupling owing to its high tolerance for misalignments.

  10. Flat-top passband filter based on parallel-coupled double microring resonators in silicon

    Science.gov (United States)

    Huang, Qingzhong; Xiao, Xi; Li, Yuntao; Li, Zhiyong; Yu, Yude; Yu, Jinzhong

    2009-08-01

    Optical filters with box-like response were designed and realized based on parallel-coupled double microrings in silicon-on-insulator. The properties of this design are simulated, considering the impact of the center-to-center distance of two rings, and coupling efficiency. Flat-top passband in the drop channel of the fabricated device was demonstrated with a 1dB bandwidth of 0.82nm, a 1dB/10dB bandwidth ratio of 0.51, an out of band rejection ratio of 14.6dB, as well as a free spectrum range of 13.6nm.

  11. Broadband Impedance Transformer Based on Asymmetric Coupled Transmission Lines in Nonhomogeneous Medium

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Krozer, Viktor; Meincke, Peter

    2007-01-01

    A new broadband quarter-wavelength impedance transformer based on an asymmetric coupled line section is presented. The bandwidth of the coupled line transformer is extended with the help of an interconnecting transmission line. An analytical model for the transformer is developed. The analysis...... of the structure reveals that a fractional bandwidth of more than 100% at –20 dB reflection level can be achieved with such a structure. An experimental transformer circuit has been designed, fabricated and tested. Theoretical and experimental results are fair agreement and confirm the established theory...

  12. A morphing approach to couple state-based peridynamics with classical continuum mechanics

    KAUST Repository

    Han, Fei

    2016-01-04

    A local/nonlocal coupling technique called the morphing method is developed to couple classical continuum mechanics with state-based peridynamics. State-based peridynamics, which enables the description of cracks that appear and propagate spontaneously, is applied to the key domain of a structure, where damage and fracture are considered to have non-negligible effects. In the rest of the structure, classical continuum mechanics is used to reduce computational costs and to simultaneously satisfy solution accuracy and boundary conditions. Both models are glued by the proposed morphing method in the transition region. The morphing method creates a balance between the stiffness tensors of classical continuum mechanics and the weighted coefficients of state-based peridynamics through the equivalent energy density of both models. Linearization of state-based peridynamics is derived by Taylor approximations based on vector operations. The discrete formulation of coupled models is also described. Two-dimensional numerical examples illustrate the validity and accuracy of the proposed technique. It is shown that the morphing method, originally developed for bond-based peridynamics, can be successfully extended to state-based peridynamics through the original developments presented here.

  13. A morphing approach to couple state-based peridynamics with classical continuum mechanics

    KAUST Repository

    Han, Fei; Lubineau, Gilles; Azdoud, Yan; Askari, Abe

    2016-01-01

    A local/nonlocal coupling technique called the morphing method is developed to couple classical continuum mechanics with state-based peridynamics. State-based peridynamics, which enables the description of cracks that appear and propagate spontaneously, is applied to the key domain of a structure, where damage and fracture are considered to have non-negligible effects. In the rest of the structure, classical continuum mechanics is used to reduce computational costs and to simultaneously satisfy solution accuracy and boundary conditions. Both models are glued by the proposed morphing method in the transition region. The morphing method creates a balance between the stiffness tensors of classical continuum mechanics and the weighted coefficients of state-based peridynamics through the equivalent energy density of both models. Linearization of state-based peridynamics is derived by Taylor approximations based on vector operations. The discrete formulation of coupled models is also described. Two-dimensional numerical examples illustrate the validity and accuracy of the proposed technique. It is shown that the morphing method, originally developed for bond-based peridynamics, can be successfully extended to state-based peridynamics through the original developments presented here.

  14. Optimization of top coupling grating for very long wavelength QWIP based on surface plasmon

    Science.gov (United States)

    Wang, Guodong; Shen, Junling; Liu, Xiaolian; Ni, Lu; Wang, Saili

    2017-09-01

    The relative coupling efficiency of two-dimensional (2D) grating based on surface plasmon for very long wavelength quantum well infrared detector is analyzed by using the three-dimensional finite-difference time domain (3D-FDTD) method algorithm. The relative coupling efficiency with respect to the grating parameters, such as grating pitch, duty ratio, and grating thickness, is analyzed. The calculated results show that the relative coupling efficiency would reach the largest value for the 14.5 μm incident infrared light when taking the grating pitch as 4.4 μm, the duty ratio as 0.325, and the grating thickness as 0.07 μm, respectively.

  15. Root-MUSIC Based Angle Estimation for MIMO Radar with Unknown Mutual Coupling

    Directory of Open Access Journals (Sweden)

    Jianfeng Li

    2014-01-01

    Full Text Available Direction of arrival (DOA estimation problem for multiple-input multiple-output (MIMO radar with unknown mutual coupling is studied, and an algorithm for the DOA estimation based on root multiple signal classification (MUSIC is proposed. Firstly, according to the Toeplitz structure of the mutual coupling matrix, output data of some specified sensors are selected to eliminate the influence of the mutual coupling. Then the reduced-dimension transformation is applied to make the computation burden lower as well as obtain a Vandermonde structure of the direction matrix. Finally, Root-MUSIC can be adopted for the angle estimation. The angle estimation performance of the proposed algorithm is better than that of estimation of signal parameters via rotational invariance techniques (ESPRIT-like algorithm and MUSIC-like algorithm. Furthermore, the proposed algorithm has lower complexity than them. The simulation results verify the effectiveness of the algorithm, and the theoretical estimation error of the algorithm is also derived.

  16. Refractive Index Sensor Based on a Metal–Insulator–Metal Waveguide Coupled with a Symmetric Structure

    Directory of Open Access Journals (Sweden)

    Shubin Yan

    2017-12-01

    Full Text Available In this study, a new refractive index sensor based on a metal–insulator–metal waveguide coupled with a notched ring resonator and stub is designed. The finite element method is used to study the propagation characteristics of the sensor. According to the calculation results, the transmission spectrum exhibits a typical Fano resonance shape. The phenomenon of Fano resonance is caused by the coupling between the broadband spectrum and narrowband spectrum. In the design, the broadband spectrum signal is generated by the stub, while the narrowband spectrum signal is generated by the notched ring resonator. In addition, the structural parameters of the resonators and the structure filled with media of different refractive indices are varied to study the sensing properties. The maximum achieved sensitivity of the sensor reached 1071.4 nm/RIU. The results reveal potential applications of the coupled system in the field of sensors.

  17. Sensitivity Enhancement of Biochemical Sensors Based on Er+3 Doped Microsphere Coupled to an External Mirror

    Directory of Open Access Journals (Sweden)

    Alireza BAHRAMPOUR

    2010-09-01

    Full Text Available In this paper we proposed an active optical sensor designed based on the Er+3-doped microsphere coupled to an external mirror. The microsphere-mirror coupling causes the degeneracy splitting of the resonance frequencies. Each of resonance frequencies splits in to two different resonance frequencies .The coupling coefficient changes as a result of altering the refractive index of surrounding medium. So, the presence of bio/chemical analytes can be detected by measuring the change of laser output power, laser frequency or the difference between frequencies of the red and blue shifted modes. In the presence of mirror at least one order of magnitude sensitivity enhancement is obtained relative to the active microsphere biochemical sensors.

  18. Experimental test of renormalization group theory on the uniaxial, dipolar coupled ferromagnet LiTbf4

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1976-01-01

    The transverse correlation range ξ and the susceptibility in the critical region has been measured by neutron scattering. A special technique required to resolve the superdiverging longitudinal correlation range has been utilized. The results for ξ together with existing specific-heat data are in...... are in remarkable agreement with the renormalization group theory of systems with marginal dimensionality. The ratio between the susceptibility amplitudes above and below Tc was found to be 2 in accordance with renormalization-group and meanfield theory....

  19. A cross-coupled-structure-based temperature sensor with reduced process variation sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Tie Meng; Cheng Xu, E-mail: tiemeng@mprc.pku.edu.c [Microprocessor Research and Development Center, Peking University, Beijing 100871 (China)

    2009-04-15

    An innovative, thermally-insensitive phenomenon of cascaded cross-coupled structures is found. And a novel CMOS temperature sensor based on a cross-coupled structure is proposed. This sensor consists of two different ring oscillators. The first ring oscillator generates pulses that have a period, changing linearly with temperature. Instead of using the system clock like in traditional sensors, the second oscillator utilizes a cascaded cross-coupled structure to generate temperature independent pulses to capture the result from the first oscillator. Due to the compensation between the two ring oscillators, errors caused by supply voltage variations and systematic process variations are reduced. The layout design of the sensor is based on the TSMC13G process standard cell library. Only three inverters are modified for proper channel width tuning without any other custom design. This allows for an easy integration of the sensor into cell-based chips. Post-layout simulations results show that an error lower than +-1.1 deg. C can be achieved in the full temperature range from -40 to 120 deg. C. As shown by SPICE simulations, the thermal insensitivity of the cross-coupled inverters can be realized for various TSMC technologies: 0.25 mum, 0.18 mum, 0.13 mum, and 65 nm.

  20. Characterization and modeling of multi-dipolar microwave plasmas: application to multi-dipolar plasma assisted sputtering; Caracterisation et modelisation des plasmas micro-onde multi-dipolaires: application a la pulverisation assistee par plasma multi-dipolaire

    Energy Technology Data Exchange (ETDEWEB)

    Tran, T.V

    2006-12-15

    The scaling up of plasma processes in the low pressure range remains a question to be solved for their rise at the industrial level. One solution is the uniform distribution of elementary plasma sources where the plasma is produced via electron cyclotron resonance (ECR) coupling. These elementary plasma sources are made up of a cylindrical permanent magnet (magnetic dipole) set at the end of a coaxial microwave line. Although of simple concept, the optimisation of these dipolar plasma sources is in fact a complex problem. It requires the knowledge, on one hand, of the configurations of static magnetic fields and microwave electric fields, and, on the other hand, of the mechanisms of plasma production in the region of high intensity magnetic field (ECR condition), and of plasma diffusion. Therefore, the experimental characterisation of the operating ranges and plasma parameters has been performed by Langmuir probes and optical emission spectroscopy on different configurations of dipolar sources. At the same time, in a first analytical approach, calculations have been made on simple magnetic field configurations, motion and trajectory of electrons in these magnetic fields, and the acceleration of electrons by ECR coupling. Then, the results have been used for the validation of the numerical modelling of the electron trajectories by using a hybrid PIC (particle-in-cell) / MC (Monte Carlo) method. The experimental study has evidenced large operating domains, between 15 and 200 W of microwave power, and from 0.5 to 15 mtorr argon pressure. The analysis of plasma parameters has shown that the region of ECR coupling is localised near the equatorial plane of the magnet and dependent on magnet geometry. These characterizations, applied to a cylindrical reactor using 48 sources, have shown that densities between 10{sup 11} and 10{sup 12} cm{sup -3} could be achieved in the central part of the volume at a few mtorr argon pressures. The modelling of electron trajectories near

  1. C-C Coupling on Single-Atom-Based Heterogeneous Catalyst.

    Science.gov (United States)

    Zhang, Xiaoyan; Sun, Zaicheng; Wang, Bin; Tang, Yu; Nguyen, Luan; Li, Yuting; Tao, Franklin Feng

    2018-01-24

    Compared to homogeneous catalysis, heterogeneous catalysis allows for ready separation of products from the catalyst and thus reuse of the catalyst. C-C coupling is typically performed on a molecular catalyst which is mixed with reactants in liquid phase during catalysis. This homogeneous mixing at a molecular level in the same phase makes separation of the molecular catalyst extremely challenging and costly. Here we demonstrated that a TiO 2 -based nanoparticle catalyst anchoring singly dispersed Pd atoms (Pd 1 /TiO 2 ) is selective and highly active for more than 10 Sonogashira C-C coupling reactions (R≡CH + R'X → R≡R'; X = Br, I; R' = aryl or vinyl). The coupling between iodobenzene and phenylacetylene on Pd 1 /TiO 2 exhibits a turnover rate of 51.0 diphenylacetylene molecules per anchored Pd atom per minute at 60 °C, with a low apparent activation barrier of 28.9 kJ/mol and no cost of catalyst separation. DFT calculations suggest that the single Pd atom bonded to surface lattice oxygen atoms of TiO 2 acts as a site to dissociatively chemisorb iodobenzene to generate an intermediate phenyl, which then couples with phenylacetylenyl bound to a surface oxygen atom. This coupling of phenyl adsorbed on Pd 1 and phenylacetylenyl bound to O ad of TiO 2 forms the product molecule, diphenylacetylene.

  2. Correction of vertical dispersion and betatron coupling for the CLIC damping ring

    CERN Document Server

    Korostelev, M S

    2006-01-01

    The sensitivity of the CLIC damping ring to various kinds of alignment errors has been studied. Without any correction, fairly small vertical misalignments of the quadrupoles and, in particular, the sextupoles, introduce unacceptable distortions of the closed orbit as well as intolerable spurious vertical dispersion and coupling due to the strong focusing optics of the damping ring. A sophisticated beam-based correction scheme has been developed to bring the design target emittances and the dynamic aperture back to the ideal value. The correction using dipolar correctors and several skew quadrupole correctors allows a minimization of the closed-orbit distortion, the cross-talk between vertical and horizontal closed orbits, the residual vertical dispersion and the betatron coupling.

  3. Tunnel-induced Dipolar Resonances in a Double-well Potential.

    Science.gov (United States)

    Schulz, Bruno; Saenz, Alejandro

    2016-11-18

    A system of two dipolar particles that are confined in a double-well potential and interact via a realistic isotropic interaction potential is investigated as a protoype for ultracold atoms with a magnetic dipole moment or ultracold dipolar heteronuclear diatomic molecules in double-well traps or in optical lattices. The resulting energy spectrum is discussed as a function of the dipole-dipole interaction strength. The variation of the strength of the dipole-dipole interaction is found to lead to various resonance phenomena. Among those are the previously discussed inelastic confinement-induced resonances as well as the dipole-induced resonances. It is found that the double-well potential gives rise to a new type of resonances, tunnel-induced dipolar ones. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations

    Science.gov (United States)

    Wang, Kaiti; Lin, Ching-Huei; Wang, Lu-Yin; Hada, Tohru; Nishimura, Yukitoshi; Turner, Drew L.; Angelopoulos, Vassilis

    2014-12-01

    Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty-two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar-type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar-type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model-calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.

  5. The structure of ions and zwitterionic lipids regulates the charge of dipolar membranes.

    Science.gov (United States)

    Szekely, Or; Steiner, Ariel; Szekely, Pablo; Amit, Einav; Asor, Roi; Tamburu, Carmen; Raviv, Uri

    2011-06-21

    In pure water, zwitterionic lipids form lamellar phases with an equilibrium water gap on the order of 2 to 3 nm as a result of the dominating van der Waals attraction between dipolar bilayers. Monovalent ions can swell those neutral lamellae by a small amount. Divalent ions can adsorb onto dipolar membranes and charge them. Using solution X-ray scattering, we studied how the structure of ions and zwitterionic lipids regulates the charge of dipolar membranes. We found that unlike monovalent ions that weakly interact with all of the examined dipolar membranes, divalent and trivalent ions adsorb onto membranes containing lipids with saturated tails, with an association constant on the order of ∼10 M(-1). One double bond in the lipid tail is sufficient to prevent divalent ion adsorption. We suggest that this behavior is due to the relatively loose packing of lipids with unsaturated tails that increases the area per lipid headgroup, enabling their free rotation. Divalent ion adsorption links two lipids and limits their free rotation. The ion-dipole interaction gained by the adsorption of the ions onto unsaturated membranes is insufficient to compensate for the loss of headgroup free-rotational entropy. The ion-dipole interaction is stronger for cations with a higher valence. Nevertheless, polyamines behave as monovalent ions near dipolar interfaces in the sense that they interact weakly with the membrane surface, whereas in the bulk their behavior is similar to that of multivalent cations. Advanced data analysis and comparison with theory provide insight into the structure and interactions between ion-induced regulated charged interfaces. This study models biologically relevant interactions between cell membranes and various ions and the manner in which the lipid structure governs those interactions. The ability to monitor these interactions creates a tool for probing systems that are more complex and forms the basis for controlling the interactions between dipolar

  6. The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission.

    Science.gov (United States)

    Kiani, Mehdi; Ghovanloo, Maysam

    2012-09-01

    Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor ( Q ) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.

  7. Stepwise π-extension of meso-alkylidenyl porphyrins through sequential 1,3-dipolar cycloaddition and redox reactions.

    Science.gov (United States)

    Park, Dowoo; Jeong, Seung Doo; Ishida, Masatoshi; Lee, Chang-Hee

    2014-08-25

    Several regioselectively π-extended, pyrrole fused porphyrinoids have been synthesized by the 1,3-dipolar cycloaddition of meso-alkylidene-(benzi)porphyrins. Pd(II) complexes gave oxidation resistant, bis-pyrrole fused adducts. The repeated 1,3-dipolar cycloaddition followed by oxidation-reduction of pentaphyrin analogs afforded π-extended porphyrin analogs.

  8. Diazo Compounds as Highly Tunable Reactants in 1,3-Dipolar Cycloaddition Reactions with Cycloalkynes†

    Science.gov (United States)

    McGrath, Nicholas A.

    2012-01-01

    Diazo compounds, which can be accessed directly from azides by deimidogenation, are shown to be extremely versatile dipoles in 1,3-dipolar cycloaddition reactions with a cyclooctyne. The reactivity of a diazo compound can be much greater or much less than its azide analog, and is enhanced markedly in polar-protic solvents. These reactivities are predictable from frontier molecular orbital energies. The most reactive diazo compound exhibited the highest known second-order rate constant to date for a dipolar cycloaddition with a cycloalkyne. These data provide a new modality for effecting chemoselective reactions in a biological context. PMID:23227302

  9. 1,3-Dipolar Cycloadditions of Diazo Compounds in the Presence of Azides.

    Science.gov (United States)

    Aronoff, Matthew R; Gold, Brian; Raines, Ronald T

    2016-04-01

    The diazo group has untapped utility in chemical biology. The tolerance of stabilized diazo groups to cellular metabolism is comparable to that of azido groups. However, chemoselectivity has been elusive, as both groups undergo 1,3-dipolar cycloadditions with strained alkynes. Removing strain and tuning dipolarophile electronics yields diazo group selective 1,3-dipolar cycloadditions that can be performed in the presence of an azido group. For example, diazoacetamide but not its azido congener react with dehydroalanine residues, as in the natural product nisin.

  10. Simulation of transverse beam splitting using time-dependent dipolar or quadrupolar kicks

    CERN Document Server

    Capoani, Federico

    2017-01-01

    Two simple systems with high relevance for accelerator physics have been studied in detail in the context of this Summer Student Project. These systems describe the motion under the influence of detuning with amplitude due to non-linear magnets and an external, time-dependent force of dipolar or quadrupolar nature.Two simple systems with high relevance for accelerator physics have been studied in detail in the context of this Summer Student Project. These systems describe the motion under the influence of detuning with amplitude due to non-linear magnets and an external, time-dependent force of dipolar or quadrupolar nature.

  11. Dipolar Quinoidal Acene Analogues as Stable Isoelectronic Structures of Pentacene and Nonacene

    KAUST Repository

    Shi, Xueliang

    2015-10-08

    Quinoidal thia-acene analogues, as the respective isoelectronic structures of pentacene and nonacene, were synthesized and an unusual 1,2-sulfur migration was observed during the Friedel-Crafts alkylation reaction. The analogues display a closed-shell quinoidal structure in the ground state with a distinctive dipolar character. In contrast to their acene isoelectronic structures, both compounds are stable because of the existence of more aromatic sextet rings, a dipolar character, and kinetic blocking. They exhibit unique packing in single crystals resulting from balanced dipole-dipole and [C-H⋯π]/[C-H⋯S] interactions.

  12. Ground-state candidate for the classical dipolar kagome Ising antiferromagnet

    Science.gov (United States)

    Chioar, I. A.; Rougemaille, N.; Canals, B.

    2016-06-01

    We have investigated the low-temperature thermodynamic properties of the classical dipolar kagome Ising antiferromagnet using Monte Carlo simulations, in the quest for the ground-state manifold. In spite of the limitations of a single-spin-flip approach, we managed to identify certain ordering patterns in the low-temperature regime and we propose a candidate for this unknown state. This configuration presents some intriguing features and is fully compatible with the extrapolations of the at-equilibrium thermodynamic behavior sampled so far, making it a very likely choice for the dipolar long-range ordered state of the classical kagome Ising antiferromagnet.

  13. A quasiparticle-based multi-reference coupled-cluster method.

    Science.gov (United States)

    Rolik, Zoltán; Kállay, Mihály

    2014-10-07

    The purpose of this paper is to introduce a quasiparticle-based multi-reference coupled-cluster (MRCC) approach. The quasiparticles are introduced via a unitary transformation which allows us to represent a complete active space reference function and other elements of an orthonormal multi-reference (MR) basis in a determinant-like form. The quasiparticle creation and annihilation operators satisfy the fermion anti-commutation relations. On the basis of these quasiparticles, a generalization of the normal-ordered operator products for the MR case can be introduced as an alternative to the approach of Mukherjee and Kutzelnigg [Recent Prog. Many-Body Theor. 4, 127 (1995); Mukherjee and Kutzelnigg, J. Chem. Phys. 107, 432 (1997)]. Based on the new normal ordering any quasiparticle-based theory can be formulated using the well-known diagram techniques. Beyond the general quasiparticle framework we also present a possible realization of the unitary transformation. The suggested transformation has an exponential form where the parameters, holding exclusively active indices, are defined in a form similar to the wave operator of the unitary coupled-cluster approach. The definition of our quasiparticle-based MRCC approach strictly follows the form of the single-reference coupled-cluster method and retains several of its beneficial properties. Test results for small systems are presented using a pilot implementation of the new approach and compared to those obtained by other MR methods.

  14. A Deep Convolutional Coupling Network for Change Detection Based on Heterogeneous Optical and Radar Images.

    Science.gov (United States)

    Liu, Jia; Gong, Maoguo; Qin, Kai; Zhang, Puzhao

    2018-03-01

    We propose an unsupervised deep convolutional coupling network for change detection based on two heterogeneous images acquired by optical sensors and radars on different dates. Most existing change detection methods are based on homogeneous images. Due to the complementary properties of optical and radar sensors, there is an increasing interest in change detection based on heterogeneous images. The proposed network is symmetric with each side consisting of one convolutional layer and several coupling layers. The two input images connected with the two sides of the network, respectively, are transformed into a feature space where their feature representations become more consistent. In this feature space, the different map is calculated, which then leads to the ultimate detection map by applying a thresholding algorithm. The network parameters are learned by optimizing a coupling function. The learning process is unsupervised, which is different from most existing change detection methods based on heterogeneous images. Experimental results on both homogenous and heterogeneous images demonstrate the promising performance of the proposed network compared with several existing approaches.

  15. A One-Structure-Based Multieffects Coupled Nanogenerator for Simultaneously Scavenging Thermal, Solar, and Mechanical Energies.

    Science.gov (United States)

    Ji, Yun; Zhang, Kewei; Yang, Ya

    2018-02-01

    Rapid advances in various energy harvesters impose the challenge on integrating them into one device structure with synergetic effects for full use of the available energies from the environment. Here, a multieffect coupled nanogenerator based on ferroelectric barium titanate is reported. It promotes the ability to simultaneously scavenging thermal, solar, and mechanical energies. By integration of a pyroelectric nanogenerator, a photovoltaic cell, and a triboelectric-piezoelectric nanogenerator in one structure with only two electrodes, multieffects interact with each other to alter the electric output, and a complementary power source with peak current of ≈1.5 µA, peak voltage of ≈7 V, and platform voltage of ≈6 V is successfully achieved. Compared with traditional hybridized nanogenerators with stacked architectures, the one-structure-based multieffects coupled nanogenerator is smaller, simpler, and less costly, showing prospective in practical applications and represents a new trend of all-in-one multiple energy scavenging.

  16. Water-Based Assembly and Purification of Plasmon-Coupled Gold Nanoparticle Dimers and Trimers

    Directory of Open Access Journals (Sweden)

    Sébastien Bidault

    2012-01-01

    Full Text Available We describe a simple one-pot water-based scheme to produce gold nanoparticle groupings with short interparticle spacings. This approach combines a cross-linking molecule and a hydrophilic passivation layer to control the level of induced aggregation. Suspensions of dimers and trimers are readily obtained using a single electrophoretic purification step. The final interparticle spacings allow efficient coupling of the particle plasmon modes as verified in extinction spectroscopy.

  17. Aqueous dye-sensitized solar cell electrolytes based on the ferricyanide-ferrocyanide redox couple

    Energy Technology Data Exchange (ETDEWEB)

    Daeneke, Torben; Spiccia, Leone [School of Chemistry and ARC Centre of Excellence for Electromaterials Science, Monash University, Victoria (Australia); Uemura, Yu.; Koumura, Nagatoshi [Research Institute for Photovoltaic Technology, National Institute of Advanced Industrial Science and Technology AIST, Ibaraki (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki (Japan); Duffy, Noel W. [CSIRO Energy Technology, Clayton, VIC (Australia); Mozer, Attila J. [School of Chemistry and ARC Centre of Excellence for Electromaterials Science, University of Wollongong, NSW (Australia); Bach, Udo [Department of Materials Engineering, Monash University, Victoria (Australia)

    2012-03-02

    Solar energy conversion efficiencies of over 4% have been achieved in DSCs constructed with aqueous electrolytes based on the ferricyanide-ferrocyanide redox couple, thereby avoiding the use of expensive, flammable and toxic solvents. This paradigm shift was made possible by the use of a hydrophobic organic carbazole dye. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Morphing wing structure with controllable twist based on adaptive bending-twist coupling

    Science.gov (United States)

    Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

    2013-06-01

    A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

  19. Morphing wing structure with controllable twist based on adaptive bending–twist coupling

    International Nuclear Information System (INIS)

    Raither, Wolfram; Heymanns, Matthias; Ermanni, Paolo; Bergamini, Andrea

    2013-01-01

    A novel semi-passive morphing airfoil concept based on variable bending–twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated. (paper)

  20. Loose Coupling of Wearable-Based INSs with Automatic Heading Evaluation

    OpenAIRE

    Bousdar Ahmed, Dina; Munoz Diaz, Estefania

    2017-01-01

    Position tracking of pedestrians by means of inertial sensors is a highly explored field of research. In fact, there are already many approaches to implement inertial navigation systems (INSs). However, most of them use a single inertial measurement unit (IMU) attached to the pedestrian’s body. Since wearable-devices will be given items in the future, this work explores the implementation of an INS using two wearable-based IMUs. A loosely coupled approach is proposed to combine the outputs of...

  1. Gender Inequality in the Couple Relationship and Leisure-Based Physical Exercise.

    Directory of Open Access Journals (Sweden)

    Ellen Annandale

    Full Text Available To analyse whether gender inequality in the couple relationship was related to leisure-based physical activity, after controlling for earlier physical activity and confounders.Data drawn from the Northern Swedish Cohort of all pupils in their final year of compulsory schooling in a town in the North of Sweden. The sample consisted of 772 respondents (n = 381 men, n = 391 women in the 26-year follow-up (in 2007, aged 42 who were either married or cohabiting. Ordinal regression, for men and women separately, was used to assess the association between gender inequality (measured as self-perceived equality in the couple relationship using dummy variables and a measure of exercise frequency, controlling for prior exercise frequency, socioeconomic status, the presence of children in the home, and longer than usual hours in paid work.The perception of greater gender equality in the couple relationship was associated with higher levels of physical activity for both men and women. This remained significant when the other variables were controlled for. Amongst men the confidence intervals were high.The results point to the potential of perceived gender equality in the couple relationship to counteract the general time poverty and household burden that often arises from the combination of paid work and responsibility for children and the home, especially for women. The high confidence intervals among men indicate the need for more research within the field with larger samples.

  2. Gender Inequality in the Couple Relationship and Leisure-Based Physical Exercise.

    Science.gov (United States)

    Annandale, Ellen; Hammarström, Anne

    2015-01-01

    To analyse whether gender inequality in the couple relationship was related to leisure-based physical activity, after controlling for earlier physical activity and confounders. Data drawn from the Northern Swedish Cohort of all pupils in their final year of compulsory schooling in a town in the North of Sweden. The sample consisted of 772 respondents (n = 381 men, n = 391 women) in the 26-year follow-up (in 2007, aged 42) who were either married or cohabiting. Ordinal regression, for men and women separately, was used to assess the association between gender inequality (measured as self-perceived equality in the couple relationship using dummy variables) and a measure of exercise frequency, controlling for prior exercise frequency, socioeconomic status, the presence of children in the home, and longer than usual hours in paid work. The perception of greater gender equality in the couple relationship was associated with higher levels of physical activity for both men and women. This remained significant when the other variables were controlled for. Amongst men the confidence intervals were high. The results point to the potential of perceived gender equality in the couple relationship to counteract the general time poverty and household burden that often arises from the combination of paid work and responsibility for children and the home, especially for women. The high confidence intervals among men indicate the need for more research within the field with larger samples.

  3. Steady-State Core Temperature Prediction Based on GAMMA+/CAPP Coupling

    International Nuclear Information System (INIS)

    Tak, Nam-il; Lee, Hyun-Chul; Lim, Hong-Sik

    2015-01-01

    In spite of sizable applications of the GAMMA+ code for the thermo-fluid analysis and design of a prismatic VHTR, the existing works are limited to stand-alone calculations. In the stand-alone calculations, information from the neutronic analysis (e.g., reactor power density profile) was considered only once i.e., when the calculations get started. For the neutronic analysis and design of a VHTR, the CAPP code, which is also under development at KAERI, is used. The main objective of this paper is to investigate the capability of GAMMA+ and CAPP coupling and to examine the results of the coupled analysis. Based on the coupling of GAMMA+ and CAPP, the steady-state core temperature was investigated in this work. It is found that the communication of data was successful. And the results of the GAMMA+ and CAPP coupling are found to be reasonable. The design modification of PMR200 is required to satisfy the design limit for the hot spot fuel temperature

  4. FDTD based transition time dependent crosstalk analysis for coupled RLC interconnects

    International Nuclear Information System (INIS)

    Sharma, Devendra Kumar; Kaushik, Brajesh Kumar; Sharma, R. K.

    2014-01-01

    The performance of high density chips operating in the GHz range is mostly affected by on-chip interconnects. The interconnect delay depends on many factors, a few of them are inputs toggling patterns, line and coupling parasitics, input rise/fall time and source/load characteristics. The transition time of the input is of prime importance in high speed circuits. This paper addresses the FDTD based analysis of transition time effects on functional and dynamic crosstalk. The analysis is carried out for equal and unequal transition times of coupled inputs. The analysis of the effects of unequal rise time is equally important because practically, it is quite common to have mismatching in the rise time of the signals transmitting through different length wires. To demonstrate the effects, two distributed RLC lines coupled inductively and capacitively are taken into consideration. The FDTD technique is used because it gives accurate results and carries time domain analysis of coupled lines. The number of lumps in SPICE simulations is considered the same as those of spatial segments. To validate the FDTD computed results, SPICE simulations are run and results are compared. A good agreement of the computed results has been observed with respect to SPICE simulated results. An average error of less than 3.2% is observed in the computation of the performance parameters using the proposed method. (semiconductor integrated circuits)

  5. Selective sp3 C-H alkylation via polarity-match-based cross-coupling.

    Science.gov (United States)

    Le, Chip; Liang, Yufan; Evans, Ryan W; Li, Ximing; MacMillan, David W C

    2017-07-06

    The functionalization of carbon-hydrogen (C-H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C-H functionalization reactions involve C(sp 3 )-C(sp 2 ) coupling, there is a growing demand for C-H alkylation reactions, wherein sp 3 C-H bonds are replaced with sp 3 C-alkyl groups. Here we describe a polarity-match-based selective sp 3 C-H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C-H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl-alkyl fragment coupling. The sp 3 C-H alkylation is highly selective for the α-C-H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

  6. Selective sp3 C–H alkylation via polarity-match-based cross-coupling

    Science.gov (United States)

    Le, Chip; Liang, Yufan; Evans, Ryan W.; Li, Ximing; MacMillan, David W. C.

    2017-01-01

    The functionalization of carbon–hydrogen (C–H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence1. Although many C–H functionalization reactions involve C(sp3)–C(sp2) coupling, there is a growing demand for C–H alkylation reactions, wherein sp3 C–H bonds are replaced with sp3 C–alkyl groups. Here we describe a polarity-match-based selective sp3 C–H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C–H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl–alkyl fragment coupling. The sp3 C–H alkylation is highly selective for the α-C–H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry. PMID:28636596

  7. Spatial layout optimization design of multi-type LEDs lighting source based on photoelectrothermal coupling theory

    Science.gov (United States)

    Xue, Lingyun; Li, Guang; Chen, Qingguang; Rao, Huanle; Xu, Ping

    2018-03-01

    Multiple LED-based spectral synthesis technology has been widely used in the fields of solar simulator, color mixing, and artificial lighting of plant factory and so on. Generally, amounts of LEDs are spatially arranged with compact layout to obtain the high power density output. Mutual thermal spreading among LEDs will produce the coupled thermal effect which will additionally increase the junction temperature of LED. Affected by the Photoelectric thermal coupling effect of LED, the spectrum of LED will shift and luminous efficiency will decrease. Correspondingly, the spectral synthesis result will mismatch. Therefore, thermal management of LED spatial layout plays an important role for multi-LEDs light source system. In the paper, the thermal dissipation network topology model considering the mutual thermal spreading effect among the LEDs is proposed for multi-LEDs system with various types of power. The junction temperature increment cased by the thermal coupling has the great relation with the spatial arrangement. To minimize the thermal coupling effect, an optimized method of LED spatial layout for the specific light source structure is presented and analyzed. The results showed that layout of LED with high-power are arranged in the corner and low-power in the center. Finally, according to this method, it is convenient to determine the spatial layout of LEDs in a system having any kind of light source structure, and has the advantages of being universally applicable to facilitate adjustment.

  8. Selective sp3 C-H alkylation via polarity-match-based cross-coupling

    Science.gov (United States)

    Le, Chip; Liang, Yufan; Evans, Ryan W.; Li, Ximing; MacMillan, David W. C.

    2017-07-01

    The functionalization of carbon-hydrogen (C-H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C-H functionalization reactions involve C(sp3)-C(sp2) coupling, there is a growing demand for C-H alkylation reactions, wherein sp3 C-H bonds are replaced with sp3 C-alkyl groups. Here we describe a polarity-match-based selective sp3 C-H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C-H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl-alkyl fragment coupling. The sp3 C-H alkylation is highly selective for the α-C-H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

  9. Probe And Enhancement Of SBS Based Phonons In Infrared Fibers Using Waveguide Coupled External Radiation

    Science.gov (United States)

    Yu, Chung; Chong, Yat C.; Fong, Chee K.

    1989-06-01

    Interaction of GHz and MHz radiation with CO2 laser propagation in a silver halide fiber using sBs based phonon coupling is furthet investigated. The external signal serves to both probe and enhance laser generated sBs phonons in the fiber. Efficient coupling of microwave radiation into the fiber is accomplished by placing the fiber in a hollow metallic waveguide, designed and constructed to transmit the dominant mode in the 0.9-2.0 GHz band. MHz radiation is conveniently coupled into the fiber using the guided microwave radiation as carrier. Phonon emissions from the fiber under CO2 laser pumping are first established on a spectrum analyzer; low frequency generators ale then tuned to match these frequencies and their maximum interaction recorded. Such interactions are systematically studied by monitoring the amplitude and waveform of the reflected and transmitted laser pulse at various power levels and frequencies of the externally coupled radiation. A plot of reflected laser power versus incident laser power reveals a distinct sBs generated phonon threshold. Variouslaunch directions of the GHz and MHz radiation with respect to the direction of laser propagation are realized to verify theory governing sBs interactions. The MHz radiation and its associated phonons in the fiber are convenient tools for probing sBs related phenomenon in infrared fibers.

  10. ZnO nanowire-based glucose biosensors with different coupling agents

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Juneui [Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Lim, Sangwoo, E-mail: swlim@yonsei.ac.kr [Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Fabrication of ZnO nanowire-based glucose biosensors using different coupling agents. Black-Right-Pointing-Pointer Highest sensitivity for (3-aminopropyl)methyldiethoxysilane-treated biosensor. Black-Right-Pointing-Pointer Larger amount of glucose oxidase and lower electron transfer resistance for (3-aminopropyl)methyldiethoxysilane-treated biosensor. - Abstract: ZnO-nanowire-based glucose biosensors were fabricated by immobilizing glucose oxidase (GOx) onto a linker attached to ZnO nanowires. Different coupling agents were used, namely (3-aminopropyl)trimethoxysilane (APTMS), (3-aminopropyl)triethoxysilane (APTES), and (3-aminopropyl)methyldiethoxysilane (APS), to increase the affinity of GOx binding to ZnO nanowires. The amount of GOx immobilized on the ZnO nanowires, the performance, sensitivity, and Michaelis-Menten constant of each biosensor, and the electron transfer resistance through the biosensor were all measured in order to investigate the effect of the coupling agent on the ZnO nanowire-based biosensor. Among the different biosensors, the APS-treated biosensor had the highest sensitivity (17.72 {mu}A cm{sup -2} mM{sup -1}) and the lowest Michaelis-Menten constant (1.37 mM). Since APS-treated ZnO nanowires showed the largest number of C-N groups and the lowest electron transfer resistance through the biosensor, we concluded that these properties were the key factors in the performance of APS-treated glucose biosensors.

  11. ZnO nanowire-based glucose biosensors with different coupling agents

    International Nuclear Information System (INIS)

    Jung, Juneui; Lim, Sangwoo

    2013-01-01

    Highlights: ► Fabrication of ZnO nanowire-based glucose biosensors using different coupling agents. ► Highest sensitivity for (3-aminopropyl)methyldiethoxysilane-treated biosensor. ► Larger amount of glucose oxidase and lower electron transfer resistance for (3-aminopropyl)methyldiethoxysilane-treated biosensor. - Abstract: ZnO-nanowire-based glucose biosensors were fabricated by immobilizing glucose oxidase (GOx) onto a linker attached to ZnO nanowires. Different coupling agents were used, namely (3-aminopropyl)trimethoxysilane (APTMS), (3-aminopropyl)triethoxysilane (APTES), and (3-aminopropyl)methyldiethoxysilane (APS), to increase the affinity of GOx binding to ZnO nanowires. The amount of GOx immobilized on the ZnO nanowires, the performance, sensitivity, and Michaelis–Menten constant of each biosensor, and the electron transfer resistance through the biosensor were all measured in order to investigate the effect of the coupling agent on the ZnO nanowire-based biosensor. Among the different biosensors, the APS-treated biosensor had the highest sensitivity (17.72 μA cm −2 mM −1 ) and the lowest Michaelis–Menten constant (1.37 mM). Since APS-treated ZnO nanowires showed the largest number of C-N groups and the lowest electron transfer resistance through the biosensor, we concluded that these properties were the key factors in the performance of APS-treated glucose biosensors.

  12. Development of a CANDU Moderator Analysis Model; Based on Coupled Solver

    International Nuclear Information System (INIS)

    Yoon, Churl; Park, Joo Hwan

    2006-01-01

    A CFD model for predicting the CANDU-6 moderator temperature has been developed for several years in KAERI, which is based on CFX-4. This analytic model(CFX4-CAMO) has some strength in the modeling of hydraulic resistance in the core region and in the treatment of heat source term in the energy equations. But the convergence difficulties and slow computing speed reveal to be the limitations of this model, because the CFX-4 code adapts a segregated solver to solve the governing equations with strong coupled-effect. Compared to CFX-4 using segregated solver, CFX-10 adapts high efficient and robust coupled-solver. Before December 2005 when CFX-10 was distributed, the previous version of CFX-10(CFX-5. series) also adapted coupled solver but didn't have any capability to apply porous media approaches correctly. In this study, the developed moderator analysis model based on CFX- 4 (CFX4-CAMO) is transformed into a new moderator analysis model based on CFX-10. The new model is examined and the results are compared to the former

  13. A Plasmonic Temperature-Sensing Structure Based on Dual Laterally Side-Coupled Hexagonal Cavities

    Directory of Open Access Journals (Sweden)

    Yiyuan Xie

    2016-05-01

    Full Text Available A plasmonic temperature-sensing structure, based on a metal-insulator-metal (MIM waveguide with dual side-coupled hexagonal cavities, is proposed and numerically investigated by using the finite-difference time-domain (FDTD method in this paper. The numerical simulation results show that a resonance dip appears in the transmission spectrum. Moreover, the full width of half maximum (FWHM of the resonance dip can be narrowed down, and the extinction ratio can reach a maximum value by tuning the coupling distance between the waveguide and two cavities. Based on a linear relationship between the resonance dip and environment temperature, the temperature-sensing characteristics are discussed. The temperature sensitivity is influenced by the side length and the coupling distance. Furthermore, for the first time, two concepts—optical spectrum interference (OSI and misjudge rate (MR—are introduced to study the temperature-sensing resolution based on spectral interrogation. This work has some significance in the design of nanoscale optical sensors with high temperature sensitivity and a high sensing resolution.

  14. Loose Coupling of Wearable-Based INSs with Automatic Heading Evaluation

    Directory of Open Access Journals (Sweden)

    Dina Bousdar Ahmed

    2017-11-01

    Full Text Available Position tracking of pedestrians by means of inertial sensors is a highly explored field of research. In fact, there are already many approaches to implement inertial navigation systems (INSs. However, most of them use a single inertial measurement unit (IMU attached to the pedestrian’s body. Since wearable-devices will be given items in the future, this work explores the implementation of an INS using two wearable-based IMUs. A loosely coupled approach is proposed to combine the outputs of wearable-based INSs. The latter are based on a pocket-mounted IMU and a foot-mounted IMU. The loosely coupled fusion combines the output of the two INSs not only when these outputs are least erroneous, but also automatically favoring the best output. This approach is named smart update. The main challenge is determining the quality of the heading estimation of each INS, which changes every time. In order to address this, a novel concept to determine the quality of the heading estimation is presented. This concept is subject to a patent application. The results show that the position error rate of the loosely coupled fusion is 10 cm/s better than either the foot INS’s or pocket INS’s error rate in 95% of the cases.

  15. Loose Coupling of Wearable-Based INSs with Automatic Heading Evaluation.

    Science.gov (United States)

    Bousdar Ahmed, Dina; Munoz Diaz, Estefania

    2017-11-03

    Position tracking of pedestrians by means of inertial sensors is a highly explored field of research. In fact, there are already many approaches to implement inertial navigation systems (INSs). However, most of them use a single inertial measurement unit (IMU) attached to the pedestrian's body. Since wearable-devices will be given items in the future, this work explores the implementation of an INS using two wearable-based IMUs. A loosely coupled approach is proposed to combine the outputs of wearable-based INSs. The latter are based on a pocket-mounted IMU and a foot-mounted IMU. The loosely coupled fusion combines the output of the two INSs not only when these outputs are least erroneous, but also automatically favoring the best output. This approach is named smart update. The main challenge is determining the quality of the heading estimation of each INS, which changes every time. In order to address this, a novel concept to determine the quality of the heading estimation is presented. This concept is subject to a patent application. The results show that the position error rate of the loosely coupled fusion is 10 cm/s better than either the foot INS's or pocket INS's error rate in 95% of the cases.

  16. Couple based family planning education: changes in male involvement and contraceptive use among married couples in Jimma Zone, Ethiopia.

    Science.gov (United States)

    Tilahun, Tizta; Coene, Gily; Temmerman, Marleen; Degomme, Olivier

    2015-07-21

    Family planning contributes substantially in achieving the Millennium Development Goals. Recently, male involvement has gained considerable attention in family planning programs but the implementation thereof remains a challenge. In that context, our study aimed at measuring the effect of a six-month-long family planning education program on male involvement in family planning, as well as on couples' contraceptive practice. We conducted a quasi-experimental research among 811 married couples in Jimma Zone, southwest Ethiopia. Our study consisted of an intervention and a control group for comparative purpose; and surveyed before and after the implementation of the intervention. The intervention consisted of family planning education, given to both men and women at the household level in the intervention arm, in addition to monthly community gatherings. During the intervention period, households in the control group were not subject to particular activities but had access to routine health care services. We obtained follow-up data from 760 out of 786 (96.7%) couples who were originally enrolled in the survey. Findings were compared within and between groups before and after intervention surveys. At the baseline, contraceptive use in both control and intervention households were similar. After the intervention, we observed among men in the intervention arm a significantly higher level of willingness to be actively involved in family planning compared to the men in the control arm (p family planning issues was less reported within the control group, both in the case of men and women ((p = 0.031) and (p family planning educational intervention, which includes both spouses and promotes spousal communication, might be useful to foster contraceptive practice among couples. The results also offer practical information on the benefits of male involvement in family planning as a best means to increase contraceptive use. Thus, providing opportunities to reinforce

  17. Wave Vector Dependent Susceptibility at T>Tc in a Dipolar Ising Ferromagnet

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Holmes, L. M:; Guggenheim, H. J.

    1974-01-01

    The wave-vector-dependent susceptibility of LiTbF4 has been investigated by means of neutron scattering. The observations show a singularity of the susceptibility near wave vector Q=0 which is characteristic of the dipolar Coulomb interaction and good agreement with theory is obtained...

  18. A kinetic study of 1,3-dipolar cycloadditions in micellar media

    NARCIS (Netherlands)

    Rispens, T; Engberts, JBFN

    2003-01-01

    The kinetics of the 1,3-dipolar cycloadditions (DC) of benzonitrile oxide with a series of N-substituted maleimides in micellar media have been investigated. Surfactants studied include anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide, and a series of nonionic alkyl

  19. Electron dynamics during substorm dipolarization in Mercury's magnetosphere

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    2005-11-01

    Full Text Available We examine the nonlinear dynamics of electrons during the expansion phase of substorms at Mercury using test particle simulations. A simple model of magnetic field line dipolarization is designed by rescaling a magnetic field model of the Earth's magnetosphere. The results of the simulations demonstrate that electrons may be subjected to significant energization on the time scale (several seconds of the magnetic field reconfiguration. In a similar manner to ions in the near-Earth's magnetosphere, it is shown that low-energy (up to several tens of eV electrons may not conserve the second adiabatic invariant during dipolarization, which leads to clusters of bouncing particles in the innermost magnetotail. On the other hand, it is found that, because of the stretching of the magnetic field lines, high-energy electrons (several keVs and above do not behave adiabatically and possibly experience meandering (Speiser-type motion around the midplane. We show that dipolarization of the magnetic field lines may be responsible for significant, though transient, (a few seconds precipitation of energetic (several keVs electrons onto the planet's surface. Prominent injections of energetic trapped electrons toward the planet are also obtained as a result of dipolarization. These injections, however, do not exhibit short-lived temporal modulations, as observed by Mariner-10, which thus appear to follow from a different mechanism than a simple convection surge.

  20. On the Gross–Pitaevskii equation for trapped dipolar quantum gases

    KAUST Repository

    Carles, Ré mi; Markowich, Peter A; Sparber, Christof

    2008-01-01

    We study the time-dependent Gross-Pitaevskii equation describing Bose-Einstein condensation of trapped dipolar quantum gases. Existence and uniqueness as well as the possible blow-up of solutions are studied. Moreover, we discuss the problem of dimension reduction for this nonlinear and nonlocal Schrödinger equation. © 2008 IOP Publishing Ltd and London Mathematical Society.

  1. Exploring strain-promoted 1,3-dipolar cycloadditions of end functionalized polymers

    NARCIS (Netherlands)

    Ledin, Petr A; Kolishetti, Nagesh; Hudlikar, Manish S; Boons, Geert-Jan

    2014-01-01

    Strain-promoted 1,3-dipolar cycloaddition of cyclooctynes with 1,3-dipoles such as azides, nitrones, and nitrile oxides, are of interest for the functionalization of polymers. In this study, we have explored the use of a 4-dibenzocyclooctynol (DIBO)-containing chain transfer agent in reversible

  2. Tris-o-phenylenedioxycyclotriphosphazene (TPP) Inclusion Compounds Containing a Dipolar Molecular Rotor

    Czech Academy of Sciences Publication Activity Database

    Kobr, L.; Zhao, K.; Shen, Y.; Shoemaker, R. K.; Rogers, C. T.; Michl, Josef

    2014-01-01

    Roč. 14, č. 2 (2014), s. 559-568 ISSN 1528-7483 EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional support: RVO:61388963 Keywords : aromatic nanochannels * single-molecule * dynamics Subject RIV: CC - Organic Chemistry Impact factor: 4.891, year: 2014

  3. Numerical simulation of trapped dipolar quantum gases: Collapse studies and vortex dynamics

    KAUST Repository

    Sparber, Christof; Markowich, Peter; Huang, Zhongyi

    2010-01-01

    We numerically study the three dimensional Gross-Pitaevskii equation for dipolar quantum gases using a time-splitting algorithm. We are mainly concerned with numerical investigations of the possible blow-up of solutions, i.e. collapse of the condensate, and the dynamics of vortices. © American Institute of Mathematical Sciences.

  4. Nonlinear localized modes in dipolar Bose–Einstein condensates in two-dimensional optical lattices

    International Nuclear Information System (INIS)

    Rojas-Rojas, Santiago; Naether, Uta; Delgado, Aldo; Vicencio, Rodrigo A.

    2016-01-01

    Highlights: • We study discrete two-dimensional breathers in dipolar Bose–Einstein Condensates. • Important differences in the properties of three fundamental modes are found. • Norm threshold for existence of 2D breathers varies with dipolar interaction. • The Effective Potential Method is implemented for stability analysis. • Uncommon mobility of 2D discrete solitons is observed. - Abstract: We analyze the existence and properties of discrete localized excitations in a Bose–Einstein condensate loaded into a periodic two-dimensional optical lattice, when a dipolar interaction between atoms is present. The dependence of the Number of Atoms (Norm) on the energy of solutions is studied, along with their stability. Two important features of the system are shown, namely, the absence of the Norm threshold required for localized solutions to exist in finite 2D systems, and the existence of regions in the parameter space where two fundamental solutions are simultaneously unstable. This feature enables mobility of localized solutions, which is an uncommon feature in 2D discrete nonlinear systems. With attractive dipolar interaction, a non-trivial behavior of the Norm dependence is obtained, which is well described by an analytical model.

  5. Nonlinear localized modes in dipolar Bose–Einstein condensates in two-dimensional optical lattices

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Rojas, Santiago, E-mail: srojas@cefop.cl [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Naether, Uta [Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain); Delgado, Aldo [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Vicencio, Rodrigo A. [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago (Chile)

    2016-09-16

    Highlights: • We study discrete two-dimensional breathers in dipolar Bose–Einstein Condensates. • Important differences in the properties of three fundamental modes are found. • Norm threshold for existence of 2D breathers varies with dipolar interaction. • The Effective Potential Method is implemented for stability analysis. • Uncommon mobility of 2D discrete solitons is observed. - Abstract: We analyze the existence and properties of discrete localized excitations in a Bose–Einstein condensate loaded into a periodic two-dimensional optical lattice, when a dipolar interaction between atoms is present. The dependence of the Number of Atoms (Norm) on the energy of solutions is studied, along with their stability. Two important features of the system are shown, namely, the absence of the Norm threshold required for localized solutions to exist in finite 2D systems, and the existence of regions in the parameter space where two fundamental solutions are simultaneously unstable. This feature enables mobility of localized solutions, which is an uncommon feature in 2D discrete nonlinear systems. With attractive dipolar interaction, a non-trivial behavior of the Norm dependence is obtained, which is well described by an analytical model.

  6. The structure of the interface in the solvent-mediated interaction of dipolar surfaces

    International Nuclear Information System (INIS)

    Dzhavakhidze, P.G.; Kornyshev, A.A.; Levadny, V.G.

    1988-01-01

    Interaction of two dipolar surfaces separated by a polar medium is considered within the framework of nonlocal electrostatics. The dipolar-surface layers are modelled as regular lattices with fixed orientation of dipoles which are immersed into the solvent; solvent response is characterized by nonlocal dielectric function. The model is elaborated in order to reveal the role of the dypolar-layer discreteness in the electric field produced by one surface and the interaction between two surfaces (which gives rise to the so-called ''hydration'' or ''structural'' force acting between mineral surfaces and phospholipid bilayers). The discreteness effects are present only for commensurate lattices. Their special mutual arrangement then may lead to considerable reduction of structural forces, viz. the usual repulsion regime may change at short distances to attraction. Conditions are considered when repulsion is entirely replaced by attraction, i.e. the ''hydration barrier'' disappears. In appended note it is discussed the role of solvation of surface dipolar groups. It is proposed an explanation of why two modes of decay (one with oscillative fine structure) may be present in the dependence of the force upon distance, if the surface dipolar groups are immersed deep enough in the solvent, and how the long-range oscillative mode disappears when the surface is but weakly solvated

  7. On the Gross–Pitaevskii equation for trapped dipolar quantum gases

    KAUST Repository

    Carles, Rémi

    2008-09-29

    We study the time-dependent Gross-Pitaevskii equation describing Bose-Einstein condensation of trapped dipolar quantum gases. Existence and uniqueness as well as the possible blow-up of solutions are studied. Moreover, we discuss the problem of dimension reduction for this nonlinear and nonlocal Schrödinger equation. © 2008 IOP Publishing Ltd and London Mathematical Society.

  8. Anisotropic relaxation dynamics in a dipolar Fermi gas driven out of equilibrium

    DEFF Research Database (Denmark)

    Aikawa, K.; Frisch, A.; Mark, M.

    2014-01-01

    We report on the observation of a large anisotropy in the rethermalization dynamics of an ultracold dipolar Fermi gas driven out of equilibrium. Our system consists of an ultracold sample of strongly magnetic $^{167}$Er fermions, spin-polarized in the lowest Zeeman sublevel. In this system, elastic...

  9. Simulating three dimensional self-assembly of shape modified particles using magnetic dipolar forces

    NARCIS (Netherlands)

    Alink, Laurens; Marsman, G.H. (Mathijs); Woldering, L.A.; Abelmann, Leon

    2011-01-01

    The feasibility of 3D self-assembly of milli-magnetic particles that interact via magnetic dipolar forces is investigated. Typically magnetic particles, such as isotropic spheres, self-organize in stable 2D configurations. By modifying the shape of the particles, 3D self-assembly may be enabled. The

  10. A concise, efficient synthesis of sugar-based benzothiazoles through chemoselective intramolecular C-S coupling

    KAUST Repository

    Shen, Chao

    2012-01-01

    Sugar-based benzothiazoles are a new class of molecules promising for many biological applications. Here, we have synthesized a wide range of sugar-based benzothiazoles from readily accessible glycosyl thioureas by chemoselective, palladium-catalyzed C-S coupling reactions. Corroborated by theoretical calculations, a mechanistic investigation indicates that the coordination to the palladium by a pivaloyl carbonyl group and the presence of intramolecular hydrogen bonding play important roles in the efficiency and chemoselectivity of reaction. These fluorescent glycoconjugates can be observed to readily enter mammalian tumor cells and exhibit potential in vitro antitumor activity. This journal is © The Royal Society of Chemistry 2012.

  11. Mode Dynamics in the Bragg FEL Based on Coupling of Propagating and Trapped Waves

    CERN Document Server

    Ginzburg, N S; Peskov, N Yu; Rozental, R M; Sergeev, A; Zaslavsky, V Yu

    2005-01-01

    A novel Bragg FEL scheme is discussed in which an electron beam synchronously interacts with a propagating wave, and the latter is coupled to a quasi cut-off mode. This coupling is realized by either helical or asimuthally symmetric corrugation of the waveguide walls. The quasi cut-off mode provides feedback in the system leading to self-excitation of the whole system while the efficiency in steady-state regime of generation is almost completely determined by the propagating mode, synchronous to the beam. Analysis based on averaged time domain approach as well as on direct PIC code simulation shows that the efficiency of such a device in the single mode single frequency regime can be rather high. The main advantage of the novel Bragg resonator is provision of higher selectivity over transverse index than traditional scheme of Bragg FEL. The cold microwave testing of the Bragg structure based on coupling of propagating and trapped waves in the Ka band demonstrated a good agreement with theoretical consideratio...

  12. A Couple-Based Psychological Treatment for Chronic Pain and Relationship Distress.

    Science.gov (United States)

    Cano, Annmarie; Corley, Angelia M; Clark, Shannon M; Martinez, Sarah C

    2018-02-01

    Chronic pain impacts individuals with pain as well as their loved ones. Yet, there has been little attention to the social context in individual psychological treatment approaches to chronic pain management. With this need in mind, we developed a couple-based treatment, "Mindful Living and Relating," aimed at alleviating pain and suffering by promoting couples' psychological and relational flexibility skills. Currently, there is no integrative treatment that fully harnesses the power of the couple, treating both the individual with chronic pain and the spouse as two individuals who are each in need of developing greater psychological and relational flexibility to improve their own and their partners' health. Mindfulness, acceptance, and values-based action exercises were used to promote psychological flexibility. The intervention also targets relational flexibility, which we define as the ability to interact with one's partner, fully attending to the present moment, and responding empathically in a way that serves one's own and one's partner's values. To this end, the intervention also included exercises aimed at applying psychological flexibility skills to social interactions as well as emotional disclosure and empathic responding exercises to enhance relational flexibility. The case presented demonstrates that healthy coping with pain and stress may be most successful and sustainable when one is involved in a supportive relationship with someone who also practices psychological flexibility skills and when both partners use relational flexibility skills during their interactions.

  13. Spontaneous Synchronization in Two Mutually Coupled Memristor-Based Chua’s Circuits: Numerical Investigations

    Directory of Open Access Journals (Sweden)

    Eleonora Bilotta

    2014-01-01

    Full Text Available Chaotic dynamics of numerous memristor-based circuits is widely reported in literature. Recently, some works have appeared which study the problem of synchronization control of these systems in a master-slave configuration. In the present paper, the spontaneous dynamic behavior of two chaotic memristor-based Chua’s circuits, mutually interacting through a coupling resistance, was studied via computer simulations in order to study possible self-organized synchronization phenomena. The used memristor is a flux controlled memristor with a cubic nonlinearity, and it can be regarded as a time-varying memductance. The memristor, in effect, retains memory of its past dynamic and any difference in the initial conditions of the two circuits results in different values of the corresponding memductances. In this sense, due to the memory effect of the memristor, even if coupled circuits have the same parameters they do not constitute two completely identical chaotic oscillators. As is known, for nonidentical chaotic systems, in addition to complete synchronizations (CS other weaker forms of synchronization which provide correlations between the signals of the two systems can also occur. Depending on initial conditions and coupling strength, both chaotic and nonchaotic synchronization are observed for the system considered in this work.

  14. Dynamically tunable slow light based on plasmon induced transparency in disk resonators coupled MDM waveguide system

    International Nuclear Information System (INIS)

    Han, Xu; Wang, Tao; Liu, Bo; He, Yu; Tang, Jian; Li, Xiaoming

    2015-01-01

    Ultrafast and low-power dynamically tunable single channel and multichannel slow light based on plasmon induced transparencies (PITs) in disk resonators coupled to a metal-dielectric-metal (MDM) waveguide system with a nonlinear optical Kerr medium is investigated both numerically and analytically. A coupled-mode theory (CMT) is introduced to analyze this dynamically tunable single channel slow light structure. Multichannel slow light is realized in this plasmonic waveguide structure based on a bright–dark mode coupling mechanism. In order to reduce the pump intensity and obtain ultrafast response time, the traditional nonlinear Kerr material is replaced by monolayer graphene. It is found that the magnitude of the single PIT window can be controlled between 0.08 and 0.48, while the corresponding group index is controlled between 14.5 and 2.0 by dynamically decreasing pump intensity from 11.7 to 4.4 MW cm −2 . Moreover, the phase shift multiplication effect is found in this structure. This work paves a new way towards the realization of highly integrated optical circuits and networks, especially for wavelength-selective, all-optical storage and nonlinear devices. (paper)

  15. High content screening for G protein-coupled receptors using cell-based protein translocation assays

    DEFF Research Database (Denmark)

    Grånäs, Charlotta; Lundholt, Betina Kerstin; Heydorn, Arne

    2005-01-01

    G protein-coupled receptors (GPCRs) have been one of the most productive classes of drug targets for several decades, and new technologies for GPCR-based discovery promise to keep this field active for years to come. While molecular screens for GPCR receptor agonist- and antagonist-based drugs...... will continue to be valuable discovery tools, the most exciting developments in the field involve cell-based assays for GPCR function. Some cell-based discovery strategies, such as the use of beta-arrestin as a surrogate marker for GPCR function, have already been reduced to practice, and have been used...... as valuable discovery tools for several years. The application of high content cell-based screening to GPCR discovery has opened up additional possibilities, such as direct tracking of GPCRs, G proteins and other signaling pathway components using intracellular translocation assays. These assays provide...

  16. Flexoelectric Effect on Vibration of Piezoelectric Microbeams Based on a Modified Couple Stress Theory

    Directory of Open Access Journals (Sweden)

    Xingjia Li

    2017-01-01

    Full Text Available A novel electric Gibbs function was proposed for the piezoelectric microbeams (PMBs by employing a modified couple stress theory. Based on the new Gibbs function and the Euler-Bernoulli beam theory, the governing equations which incorporate the effects of couple stress, flexoelectricity, and piezoelectricity were derived for the mechanics of PMBs. The analysis of the effective bending rigidity shows the effects of size and flexoelectricity can greaten the stiffness of PMBs so that the natural frequency increases significantly compared with the Euler-Bernoulli beam, and then the mechanical and electrical properties of PMBs are enhanced compared to the classical beam. This study can guide the design of microscale piezoelectric/flexoelectric structures which may find potential applications in the microelectromechanical systems (MEMS.

  17. Periodic Forcing of a 555-IC Based Electronic Oscillator in the Strong Coupling Limit

    Science.gov (United States)

    Santillán, Moisés

    We designed and developed a master-slave electronic oscillatory system (based on the 555-timer IC working in the astable mode), and investigated its dynamic behavior regarding synchronization. For that purpose, we measured the rotation numbers corresponding to the phase-locking rhythms achieved in a large set of values of the normalized forcing frequency (NFF) and of the coupling strength between the master and the slave oscillators. In particular, we were interested in the system behavior in the strong-coupling limit, because such problem has not been extensively studied from an experimental perspective. Our results indicate that, in such a limit, a degenerate codimension-2 bifurcation point at NFF = 2 exists, in which all the phase-locking regions converge. These findings were corroborated by means of a mathematical model developed to that end, as well as by ad hoc further experiments.

  18. Nonlinear coupling analysis of coal seam floor during mining based on FLAC3D

    Institute of Scientific and Technical Information of China (English)

    YAO Duo-xi; XU Ji-ying; LU Hai-feng

    2011-01-01

    Based on the hydro-geological conditions of 1028 mining face in Suntuan Coal Mine, mining seepage strain mechanism of seam floor was simulated by a nonlinear coupling method, which applied fluid-solid coupling analysis module of FLAC3D. The results indicate that the permeability coefficient of adjoining rock changes a lot due to mining. The maximum value reaches 1 379.9 times to the original value, where it is at immediate roof of the mined-out area. According to the analysis on the seepage field, mining does not destroy water resistance of the floor aquiclude. The mining fissure does not conduct lime-stone aquifer, and it is less likely to form damage. The plastic zone does not exactly correspond to the seepage area, and the scope of the altered seepage area is much larger than the plastic zone.

  19. Structure-based drug design for G protein-coupled receptors.

    Science.gov (United States)

    Congreve, Miles; Dias, João M; Marshall, Fiona H

    2014-01-01

    Our understanding of the structural biology of G protein-coupled receptors has undergone a transformation over the past 5 years. New protein-ligand complexes are described almost monthly in high profile journals. Appreciation of how small molecules and natural ligands bind to their receptors has the potential to impact enormously how medicinal chemists approach this major class of receptor targets. An outline of the key topics in this field and some recent examples of structure- and fragment-based drug design are described. A table is presented with example views of each G protein-coupled receptor for which there is a published X-ray structure, including interactions with small molecule antagonists, partial and full agonists. The possible implications of these new data for drug design are discussed. © 2014 Elsevier B.V. All rights reserved.

  20. Measuring the coupled risks: A copula-based CVaR model

    Science.gov (United States)

    He, Xubiao; Gong, Pu

    2009-01-01

    Integrated risk management for financial institutions requires an approach for aggregating risk types (such as market and credit) whose distributional shapes vary considerably. The financial institutions often ignore risks' coupling influence so as to underestimate the financial risks. We constructed a copula-based Conditional Value-at-Risk (CVaR) model for market and credit risks. This technique allows us to incorporate realistic marginal distributions that capture essential empirical features of these risks, such as skewness and fat-tails while allowing for a rich dependence structure. Finally, the numerical simulation method is used to implement the model. Our results indicate that the coupled risks for the listed company's stock maybe are undervalued if credit risk is ignored, especially for the listed company with bad credit quality.

  1. Electromagnetically induced transparency control in terahertz metasurfaces based on bright-bright mode coupling

    Science.gov (United States)

    Yahiaoui, R.; Burrow, J. A.; Mekonen, S. M.; Sarangan, A.; Mathews, J.; Agha, I.; Searles, T. A.

    2018-04-01

    We demonstrate a classical analog of electromagnetically induced transparency (EIT) in a highly flexible planar terahertz metamaterial (MM) comprised of three-gap split-ring resonators. The keys to achieve EIT in this system are the frequency detuning and hybridization processes between two bright modes coexisting in the same unit cell as opposed to bright-dark modes. We present experimental verification of two bright modes coupling for a terahertz EIT-MM in the context of numerical results and theoretical analysis based on a coupled Lorentz oscillator model. In addition, a hybrid variation of the EIT-MM is proposed and implemented numerically to dynamically tune the EIT window by incorporating photosensitive silicon pads in the split gap region of the resonators. As a result, this hybrid MM enables the active optical control of a transition from the on state (EIT mode) to the off state (dipole mode).

  2. Micellar dipolar rearrangement is sensitive to hydrophobic chain length: Implication for structural switchover of piroxicam.

    Science.gov (United States)

    Sethy, Dasaratha; Chakraborty, Hirak

    2016-10-01

    The interfacial properties of the membrane are exceptionally vital in drug-membrane interaction. They not only select out a particular prototropic form of the drug molecule for incorporation, but are also potent enough to induce structural switchover of these drugs in several cases. In this work, we quantitatively monitored the change in dipolar rearrangement of the micellar interface (as a simplified membrane mimic) by measuring the dielectric constant and dipole potential with the micellization of SDS at pH 3.6. The dielectric constant and dipole potential were measured utilizing the fluorescence of polarity sensitive probe, pyrene and potential-sensitive probe, di-8-ANEPPS, respectively. Our study demonstrates that the change in dipolar rearrangement directly influences the switchover equilibrium between the anionic and neutral from of piroxicam. We have further extended our work to evaluate the effect of hydrophobic chain length of the surfactants on the dipolar rearrangement and its effect on the structural switchover of piroxicam. It is interesting that the extent of switchover of piroxicam is directly correlated with the dipolar rearrangement induced bythe varying hydrophobic chain length of the surfactants. To the best of our knowledge, our results constitute the first report to show the dependence of dipole potential on the hydrophobic chain length of the surfactant and demonstrate that the dipolar rearrangement directly tunes the extent of structural switchover of piroxicam, which was so far only intuitive. We consider that this new finding would have promising implication in drug distribution and drug efficacy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Base free aryl coupling of diazonium compounds and boronic esters: self-activation allowing an overall highly practical process.

    Science.gov (United States)

    Bonin, Hélène; Delbrayelle, Dominique; Demonchaux, Patrice; Gras, Emmanuel

    2010-04-21

    Boronic esters have long been considered as poor partners in cross-coupling reactions with arene diazoniums. Here is reported an unprecedented application of self-activated boronic esters in a base-free cross-coupling reaction with diazonium salts under mild and user friendly conditions.

  4. Refractive index modulation based on excitonic effects in GaInAs-InP coupled asymmetric quantum wells

    DEFF Research Database (Denmark)

    Thirstrup, Carsten

    1995-01-01

    The effect of excitons in GaInAs-InP coupled asymmetric quantum wells on the refractive index modulation, is analyzed numerically using a model based on the effective mass approximation. It is shown that two coupled quantum wells brought in resonance by an applied electric field will, due...

  5. Improving couples' quality of life through a Web-based prostate cancer education intervention.

    Science.gov (United States)

    Song, Lixin; Rini, Christine; Deal, Allison M; Nielsen, Matthew E; Chang, Hao; Kinneer, Patty; Teal, Randall; Johnson, David C; Dunn, Mary W; Mark, Barbara; Palmer, Mary H

    2015-03-01

    To evaluate the feasibility and acceptability of a newly developed web-based, couple-oriented intervention called Prostate Cancer Education and Resources for Couples (PERC). Quantitative, qualitative, mixed-methods approach. Oncology outpatient clinics at the University of North Carolina (UNC) Lineberger Comprehensive Cancer Center at UNC–Chapel Hill. 26 patients with localized prostate cancer (PCa) and their partners. Pre- and postpilot quantitative assessments and a postpilot qualitative interview were conducted. General and PCa-specific symptoms, quality of life, psychosocial factors, PERC’s ease of use, and web activities. Improvement was shown in some PCa-specific and general symptoms (small effect sizes for patients and small-to-medium effect sizes for partners), overall quality of life, and physical and social domains of quality of life for patients (small effect sizes). Web activity data indicated high PERC use. Qualitative and quantitative analyses indicated that participants found PERC easy to use and understand,as well as engaging, of high quality, and relevant. Overall, participants were satisfied with PERC and reported that PERC improved their knowledge about symptom management and communication as a couple. PERC was a feasible, acceptable method of reducing the side effects of PCa treatment–related symptoms and improving quality of life. PERC has the potential to reduce the negative impacts of symptoms and enhance quality of life for patients with localized PCa and their partners, particularly for those who live in rural areas and have limited access to post-treatment supportive care.

  6. Modeling of thermal coupling in VO2-based oscillatory neural networks

    Science.gov (United States)

    Velichko, Andrey; Belyaev, Maksim; Putrolaynen, Vadim; Perminov, Valentin; Pergament, Alexander

    2018-01-01

    In this study, we have demonstrated the possibility of using the thermal coupling to control the dynamics of operation of coupled VO2 oscillators. Based on the example of a 'switch-microheater' pair, we have explored the synchronization and dissynchronization modes of a single oscillator with respect to an external harmonic heat impact. The features of changes in the spectra are shown, in particular, the effect of the natural frequency attraction to the affecting signal frequency and the self-oscillation noise reduction effects at synchronization. The time constant of the temperature effect for the considered system configuration is in the range 7-140 μs, which allows operation in the oscillation frequency range of up to ∼70 kHz. A model estimate of the minimum temperature sensitivity of the switch is δTswitch ∼ 0.2 K, and the effective action radius RTC of the switch-to-switch thermal coupling is not less than 25 μm. Nevertheless, as the simulation shows, the frequency range can be significantly extended up to the values of 1-30 GHz if using nanometer-scale switches (heaters). article>

  7. Development of a novel positive psychology-based intervention for couples post-stroke.

    Science.gov (United States)

    Terrill, Alexandra L; Reblin, Maija; MacKenzie, Justin J; Cardell, Beth; Einerson, Jackie; Berg, Cynthia A; Majersik, Jennifer J; Richards, Lorie

    2018-02-01

    Stroke provides challenges for survivors and partner caregivers. Stroke survivors and caregivers are interconnected in their emotional health, including depression, a common stroke sequelae. The purpose of this study was to develop and test the feasibility of a dyadic positive psychology-based intervention (PPI) for couples coping poststroke. Community-dwelling couples consisted of 1 partner who had a stroke ≥6 months ago and a cohabiting partner caregiver. One or both partner(s) had to report depressive symptoms. The PPI consisted of 1 brief face-to-face training session and an 8-week self-administered intervention in which participants were instructed to engage in at least 2 activities alone and 2 together each week. Two dyads were randomly assigned to a waitlist control to test feasibility of this process. Baseline, postintervention, and 3-month follow-up assessments and post-program feedback were obtained. Descriptive statistics were used to analyze sample characteristics, recruitment and retention rates, adherence, key pre- and postintervention outcomes, and satisfaction with the intervention. Eleven of 20 couples responding to recruitment letters were enrolled in the study. Ten of 11 dyads completed the program. All participants engaged in activities for at least 6 of 8 weeks. Feedback data indicated participant satisfaction with the intervention, and key outcome measures demonstrated adequate variability. The self-administered dyadic PPI is feasible for implementation with couples poststroke. The PPI represents a first step in a novel dyadic approach in this population. Recruitment, enrollment and attrition rates, and feedback will be used to inform a larger randomized trial. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Exploiting Flexibility in Coupled Electricity and Natural Gas Markets: A Price-Based Approach

    DEFF Research Database (Denmark)

    Ordoudis, Christos; Delikaraoglou, Stefanos; Pinson, Pierre

    2017-01-01

    Natural gas-fired power plants (NGFPPs) are considered a highly flexible component of the energy system and can facilitate the large-scale integration of intermittent renewable generation. Therefore, it is necessary to improve the coordination between electric power and natural gas systems....... Considering a market-based coupling of these systems, we introduce a decision support tool that increases market efficiency in the current setup where day-ahead and balancing markets are cleared sequentially. The proposed approach relies on the optimal adjustment of natural gas price to modify the scheduling...

  9. Study on water migration of tunnel surrounding rock in nuclear waste repository based on coupling theory

    International Nuclear Information System (INIS)

    Jiang Zhongming; Zhang Xinmin

    2008-01-01

    Excavation of tunnel changes not only the stresses and deformation of tunnel surrounding rock, but also disturbs the underground water environment in tunnel surrounding rock Water migration happens due to variation of pore water pressure and redistribution. Based on the mechanics of porous media, saturated and unsaturated hydro-mechanical coupling analysis method is employed to study the variation of the stresses, deformation and pore pressure of the surrounding rock. Case study indicates that the excavation of tunnel will induce redistribution of stress and pore water pressure. Redistribution of pore water pressure will seriously affect on evaluation of surrounding rock stability and diffusion of nucleon in the pore water. (authors)

  10. Differential BPFs with Multiple Transmission Zeros Based on Terminated Coupled Lines

    Science.gov (United States)

    Niu, Yiming; Yang, Guo; Wu, Wen

    2018-04-01

    Differential bandpass filters (BPFs) named Filter A and Filter B based on Terminated Coupled Lines (TCLs) are proposed in this letter. The TCLs contributes to not only three poles in differential-mode (DM) for wideband filtering response but also multiple zeros in both DM and common-mode (CM) offering wide DM out-of-band rejection and good CM suppression. Fabricated filters centred at 3.5 GHz with wide DM passband and wideband CM suppression have been designed and measured. The filters improved the noise suppression capability of the communication and radiometer systems. The simulated and measured results are in good agreement.

  11. A solar rechargeable flow battery based on photoregeneration of two soluble redox couples.

    Science.gov (United States)

    Liu, Ping; Cao, Yu-liang; Li, Guo-Ran; Gao, Xue-Ping; Ai, Xin-Ping; Yang, Han-Xi

    2013-05-01

    Storable sunshine, reusable rays: A solar rechargeable redox flow battery is proposed based on the photoregeneration of I(3)(-)/I(-) and [Fe(C(10)H(15))(2)](+)/Fe(C(10)H(15))(2) soluble redox couples, which can be regenerated by flowing from a discharged redox flow battery (RFB) into a dye-sensitized solar cell (DSSC) and then stored in tanks for subsequent RFB applications This technology enables effective solar-to-chemical energy conversion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Athermalization in atomic force microscope based force spectroscopy using matched microstructure coupling.

    Science.gov (United States)

    Torun, H; Finkler, O; Degertekin, F L

    2009-07-01

    The authors describe a method for athermalization in atomic force microscope (AFM) based force spectroscopy applications using microstructures that thermomechanically match the AFM probes. The method uses a setup where the AFM probe is coupled with the matched structure and the displacements of both structures are read out simultaneously. The matched structure displaces with the AFM probe as temperature changes, thus the force applied to the sample can be kept constant without the need for a separate feedback loop for thermal drift compensation, and the differential signal can be used to cancel the shift in zero-force level of the AFM.

  13. Measures of Coupling between Neural Populations Based on Granger Causality Principle.

    Science.gov (United States)

    Kaminski, Maciej; Brzezicka, Aneta; Kaminski, Jan; Blinowska, Katarzyna J

    2016-01-01

    This paper shortly reviews the measures used to estimate neural synchronization in experimental settings. Our focus is on multivariate measures of dependence based on the Granger causality (G-causality) principle, their applications and performance in respect of robustness to noise, volume conduction, common driving, and presence of a "weak node." Application of G-causality measures to EEG, intracranial signals and fMRI time series is addressed. G-causality based measures defined in the frequency domain allow the synchronization between neural populations and the directed propagation of their electrical activity to be determined. The time-varying G-causality based measure Short-time Directed Transfer Function (SDTF) supplies information on the dynamics of synchronization and the organization of neural networks. Inspection of effective connectivity patterns indicates a modular structure of neural networks, with a stronger coupling within modules than between them. The hypothetical plausible mechanism of information processing, suggested by the identified synchronization patterns, is communication between tightly coupled modules intermitted by sparser interactions providing synchronization of distant structures.

  14. Measures of coupling between neural populations based on Granger causality principle

    Directory of Open Access Journals (Sweden)

    Maciej Kaminski

    2016-10-01

    Full Text Available This paper shortly reviews the measures used to estimate neural synchronization in experimental settings. Our focus is on multivariate measures of dependence based on the Granger causality (G-causality principle, their applications and performance in respect of robustness to noise, volume conduction, common driving, and presence of a weak node. Application of G-causality measures to EEG, intracranial signals and fMRI time series is addressed. G-causality based measures defined in the frequency domain allow the synchronization between neural populations and the directed propagation of their electrical activity to be determined. The time-varying G-causality based measure Short-time Directed Transfer Function (SDTF supplies information on the dynamics of synchronization and the organization of neural networks. Inspection of effective connectivity patterns indicates a modular structure of neural networks, with a stronger coupling within modules than between them. The hypothetical plausible mechanism of information processing, suggested by the identified synchronization patterns, is communication between tightly coupled modules intermitted by sparser interactions providing synchronization of distant structures.

  15. Optimal Couple Projections for Domain Adaptive Sparse Representation-based Classification.

    Science.gov (United States)

    Zhang, Guoqing; Sun, Huaijiang; Porikli, Fatih; Liu, Yazhou; Sun, Quansen

    2017-08-29

    In recent years, sparse representation based classification (SRC) is one of the most successful methods and has been shown impressive performance in various classification tasks. However, when the training data has a different distribution than the testing data, the learned sparse representation may not be optimal, and the performance of SRC will be degraded significantly. To address this problem, in this paper, we propose an optimal couple projections for domain-adaptive sparse representation-based classification (OCPD-SRC) method, in which the discriminative features of data in the two domains are simultaneously learned with the dictionary that can succinctly represent the training and testing data in the projected space. OCPD-SRC is designed based on the decision rule of SRC, with the objective to learn coupled projection matrices and a common discriminative dictionary such that the between-class sparse reconstruction residuals of data from both domains are maximized, and the within-class sparse reconstruction residuals of data are minimized in the projected low-dimensional space. Thus, the resulting representations can well fit SRC and simultaneously have a better discriminant ability. In addition, our method can be easily extended to multiple domains and can be kernelized to deal with the nonlinear structure of data. The optimal solution for the proposed method can be efficiently obtained following the alternative optimization method. Extensive experimental results on a series of benchmark databases show that our method is better or comparable to many state-of-the-art methods.

  16. Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.

    Science.gov (United States)

    Li, Zhuoxuan; Pei, Li; Liu, Chao; Ning, Tigang; Yu, Shaowei

    2012-10-20

    Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.

  17. Super-pixel extraction based on multi-channel pulse coupled neural network

    Science.gov (United States)

    Xu, GuangZhu; Hu, Song; Zhang, Liu; Zhao, JingJing; Fu, YunXia; Lei, BangJun

    2018-04-01

    Super-pixel extraction techniques group pixels to form over-segmented image blocks according to the similarity among pixels. Compared with the traditional pixel-based methods, the image descripting method based on super-pixel has advantages of less calculation, being easy to perceive, and has been widely used in image processing and computer vision applications. Pulse coupled neural network (PCNN) is a biologically inspired model, which stems from the phenomenon of synchronous pulse release in the visual cortex of cats. Each PCNN neuron can correspond to a pixel of an input image, and the dynamic firing pattern of each neuron contains both the pixel feature information and its context spatial structural information. In this paper, a new color super-pixel extraction algorithm based on multi-channel pulse coupled neural network (MPCNN) was proposed. The algorithm adopted the block dividing idea of SLIC algorithm, and the image was divided into blocks with same size first. Then, for each image block, the adjacent pixels of each seed with similar color were classified as a group, named a super-pixel. At last, post-processing was adopted for those pixels or pixel blocks which had not been grouped. Experiments show that the proposed method can adjust the number of superpixel and segmentation precision by setting parameters, and has good potential for super-pixel extraction.

  18. Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

    Science.gov (United States)

    Malykhin, Andrey Y.; Grigorenko, Elena E.; Kronberg, Elena A.; Koleva, Rositza; Ganushkina, Natalia Y.; Kozak, Ludmila; Daly, Patrick W.

    2018-05-01

    The fortunate location of Cluster and the THEMIS P3 probe in the near-Earth plasma sheet (PS) (at X ˜ -7-9 RE) allowed for the multipoint analysis of properties and spectra of electron and proton injections. The injections were observed during dipolarization and substorm current wedge formation associated with braking of multiple bursty bulk flows (BBFs). In the course of dipolarization, a gradual growth of the BZ magnetic field lasted ˜ 13 min and it was comprised of several BZ pulses or dipolarization fronts (DFs) with duration ≤ 1 min. Multipoint observations have shown that the beginning of the increase in suprathermal ( > 50 keV) electron fluxes - the injection boundary - was observed in the PS simultaneously with the dipolarization onset and it propagated dawnward along with the onset-related DF. The subsequent dynamics of the energetic electron flux was similar to the dynamics of the magnetic field during the dipolarization. Namely, a gradual linear growth of the electron flux occurred simultaneously with the gradual growth of the BZ field, and it was comprised of multiple short ( ˜ few minutes) electron injections associated with the BZ pulses. This behavior can be explained by the combined action of local betatron acceleration at the BZ pulses and subsequent gradient drifts of electrons in the flux pile up region through the numerous braking and diverting DFs. The nonadiabatic features occasionally observed in the electron spectra during the injections can be due to the electron interactions with high-frequency electromagnetic or electrostatic fluctuations transiently observed in the course of dipolarization. On the contrary, proton injections were detected only in the vicinity of the strongest BZ pulses. The front thickness of these pulses was less than a gyroradius of thermal protons that ensured the nonadiabatic acceleration of protons. Indeed, during the injections in the energy spectra of protons the pronounced bulge was clearly observed in a

  19. A sensitive DNA biosensor based on a facile sulfamide coupling reaction for capture probe immobilization

    International Nuclear Information System (INIS)

    Wang, Qingxiang; Ding, Yingtao; Gao, Feng; Jiang, Shulian; Zhang, Bin; Ni, Jiancong; Gao, Fei

    2013-01-01

    Graphical abstract: A novel DNA biosensor was fabricated through a facile sulfamide coupling reaction between probe DNA and the sulfonic dye of 1-amino-2-naphthol-4-sulfonic acid that electrodeposited on a glassy carbon electrode. -- Highlights: •A versatile sulfonic dye of ANS was electrodeposited on a GCE. •A DNA biosensor was fabricated based on a facile sulfamide coupling reaction. •High probe DNA density of 3.18 × 10 13 strands cm −2 was determined. •A wide linear range and a low detection limit were obtained. -- Abstract: A novel DNA biosensor was fabricated through a facile sulfamide coupling reaction. First, the versatile sulfonic dye molecule of 1-amino-2-naphthol-4-sulfonate (AN-SO 3 − ) was electrodeposited on the surface of a glassy carbon electrode (GCE) to form a steady and ordered AN-SO 3 − layer. Then the amino-terminated capture probe was covalently grafted to the surface of SO 3 − -AN deposited GCE through the sulfamide coupling reaction between the amino groups in the probe DNA and the sulfonic groups in the AN-SO 3 − . The step-by-step modification process was characterized by electrochemistry and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Using Ru(NH 3 ) 6 3+ as probe, the probe density and the hybridization efficiency of the biosensor were determined to be 3.18 × 10 13 strands cm −2 and 86.5%, respectively. The hybridization performance of the biosensor was examined by differential pulse voltammetry using Co(phen) 3 3+/2+ (phen = 1,10-phenanthroline) as the indicator. The selectivity experiments showed that the biosensor presented distinguishable response after hybridization with the three-base mismatched, non-complementary and complementary sequences. Under the optimal conditions, the oxidation peak currents of Co(phen) 3 3+/2+ increased linearly with the logarithm values of the concentration of the complementary sequences in the range from 1.0 × 10 −13 M to 1.0 × 10 −8 M with

  20. Actinides analysis in emergency situation by on-line coupling between a calix[6]arene-based chromatography column and an Inductively Coupled Plasma-Mass Spectrometer

    International Nuclear Information System (INIS)

    Baghdadi, Sarah

    2015-01-01

    In the event of a nuclear crisis, involving actinides (U, Pu, Am) it is important to have fast analysis methods available in order to identify people that could be contaminated. Usually, they are performed in urine or faeces. Even though, analytical methods used with alpha detection are reliable they are lengthy and tedious to set up. This work consisted in developing an on-line coupling method between a calix[6]arene-based chromatography column and an inductively coupled plasma mass spectrometer (ICP-MS). To do so, a speciation study of actinides in mineralised urine was developed to understand the chemical equilibria happening during the actinides extraction. A protocol was elaborated to extract simultaneously all three actinides at pH = 5, then co-elute them with 0.25 mol.L -1 H 3 PO 4 . Recovery was 56 %, 74 % and 85 % for U, Pu and Am respectively. The column was then coupled to the ICP-MS. A parameter study helped defining mineralisation duration, extraction and elution flow-rates. It was then possible to propose an on-line coupling system allowing reaching detection limits lower than 0.5 mBq.L-1 for 238 U and 243 Am and lower than 5 mBq.L -1 for 239 Pu and 241 Am, for analysis duration lower than 6 hours. These analytical performances show the interest of this technique for a use in a nuclear crisis situation. (author)

  1. Spin-orbit-coupled Bose-Einstein condensates of rotating polar molecules

    Science.gov (United States)

    Deng, Y.; You, L.; Yi, S.

    2018-05-01

    An experimental proposal for realizing spin-orbit (SO) coupling of pseudospin 1 in the ground manifold 1Σ (υ =0 ) of (bosonic) bialkali polar molecules is presented. The three spin components are composed of the ground rotational state and two substates from the first excited rotational level. Using hyperfine resolved Raman processes through two select excited states resonantly coupled by a microwave, an effective coupling between the spin tensor and linear momentum is realized. The properties of Bose-Einstein condensates for such SO-coupled molecules exhibiting dipolar interactions are further explored. In addition to the SO-coupling-induced stripe structures, the singly and doubly quantized vortex phases are found to appear, implicating exciting opportunities for exploring novel quantum physics using SO-coupled rotating polar molecules with dipolar interactions.

  2. Gender-based power and couples' HIV risk in Uttar Pradesh and Uttarakhand, north India.

    Science.gov (United States)

    Agrawal, Alpna; Bloom, Shelah S; Suchindran, Chirayath; Curtis, Siân; Angeles, Gustavo

    2014-12-01

    Gender inequality is a long-recognized driver of the HIV epidemic. However, few studies have investigated the association between gender-based power and HIV risk in India, which has the world's third largest HIV epidemic. Population-based data collected in 2003 from 3,385 couples residing in Uttar Pradesh and Uttarakhand, North India, were used to examine associations between gender-based power (wife's autonomy and husband's inequitable gender attitudes) and indicators of couples' HIV risk (whether the husband had had premarital sex with someone other than his eventual spouse, extramarital sex in the past year or STI symptoms in the past year). Structural equation modeling was used to create composite variables for the gender-based power measures and test their associations with HIV risk measures. Twenty-four percent of husbands had had premarital sex, 7% had had extramarital sex in the past year and 6% had had STI symptoms in the past year. Structural equation models indicated that wives who reported higher levels of autonomy were less likely than other wives to have husbands who had had extramarital sex in the past year (direct association) or STI symptoms in the past year (indirect association). Moreover, husbands who endorsed more inequitable gender attitudes were more likely than others to report having had premarital sex with someone other than their spouse, which in turn was associated with having had extramarital sex and STI symptoms in the past year. If the associations identified in this study reflect a causal relationship between gender-based power and HIV risk behavior, then HIV prevention programs that successfully address inequitable gender roles may reduce HIV risks in North India.

  3. Research on borehole stability of shale based on seepage-stress-damage coupling model

    Directory of Open Access Journals (Sweden)

    Xiaofeng Ran

    2014-01-01

    Full Text Available In oil drilling, one of the most complicated problems is borehole stability of shale. Based on the theory of continuum damage mechanics, a modified Mohr-Coulomb failure criterion according to plastic damage evolution and the seepage-stress coupling is established. Meanwhile, the damage evolution equation which is based on equivalent plastic strain and the permeability evolution equation of shale are proposed in this paper. The physical model of borehole rock for a well in China western oilfield is set up to analyze the distribution of damage, permeability, stress, plastic strain and displacement. In the calculation process, the influence of rock damage to elastic modulus, cohesion and permeability is involved by writing a subroutine for ABAQUS. The results show that the rock damage evolution has a significant effect to the plastic strain and stress in plastic zone. Different drilling fluid density will produce different damage in its value, range and type. This study improves the theory of mechanical mechanism of borehole collapse and fracture, and provides a reference for the further research of seepage-stress-chemical-damage coupling of wall rock.

  4. A thin layer fiber-coupled luminescence dosimeter based on Al2O3:C

    DEFF Research Database (Denmark)

    Klein, F.A.; Greilich, Steffen; Andersen, Claus Erik

    2011-01-01

    In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence of the intr......In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence...... of the introduced polymer host matrix on the dosimetric properties was observed. Depth-dose measurements with the new detectors in a 142.66 MeV proton and 270.55 MeV/u carbon ion beam are presented as example applications. We used an RL protocol with saturated crystals allowing for time-effective measurements...... without sensitivity corrections. For protons, a relative luminescence efficiency hHCP of 0.715 0.014 was found in the Bragg peak. For carbon ions, a value of 0.498 0.001 was found in the entrance channel, 0.205 0.015 in the Bragg peak, and a mean of 0.413 0.050 in the tail region. The mean range...

  5. An advanced Lithium-ion battery optimal charging strategy based on a coupled thermoelectric model

    International Nuclear Information System (INIS)

    Liu, Kailong; Li, Kang; Yang, Zhile; Zhang, Cheng; Deng, Jing

    2017-01-01

    Lithium-ion batteries are widely adopted as the power supplies for electric vehicles. A key but challenging issue is to achieve optimal battery charging, while taking into account of various constraints for safe, efficient and reliable operation. In this paper, a triple-objective function is first formulated for battery charging based on a coupled thermoelectric model. An advanced optimal charging strategy is then proposed to develop the optimal constant-current-constant-voltage (CCCV) charge current profile, which gives the best trade-off among three conflicting but important objectives for battery management. To be specific, a coupled thermoelectric battery model is first presented. Then, a specific triple-objective function consisting of three objectives, namely charging time, energy loss, and temperature rise (both the interior and surface), is proposed. Heuristic methods such as Teaching-learning-based-optimization (TLBO) and particle swarm optimization (PSO) are applied to optimize the triple-objective function, and their optimization performances are compared. The impacts of the weights for different terms in the objective function are then assessed. Experimental results show that the proposed optimal charging strategy is capable of offering desirable effective optimal charging current profiles and a proper trade-off among the conflicting objectives. Further, the proposed optimal charging strategy can be easily extended to other battery types.

  6. Output Feedback-Based Boundary Control of Uncertain Coupled Semilinear Parabolic PDE Using Neurodynamic Programming.

    Science.gov (United States)

    Talaei, Behzad; Jagannathan, Sarangapani; Singler, John

    2018-04-01

    In this paper, neurodynamic programming-based output feedback boundary control of distributed parameter systems governed by uncertain coupled semilinear parabolic partial differential equations (PDEs) under Neumann or Dirichlet boundary control conditions is introduced. First, Hamilton-Jacobi-Bellman (HJB) equation is formulated in the original PDE domain and the optimal control policy is derived using the value functional as the solution of the HJB equation. Subsequently, a novel observer is developed to estimate the system states given the uncertain nonlinearity in PDE dynamics and measured outputs. Consequently, the suboptimal boundary control policy is obtained by forward-in-time estimation of the value functional using a neural network (NN)-based online approximator and estimated state vector obtained from the NN observer. Novel adaptive tuning laws in continuous time are proposed for learning the value functional online to satisfy the HJB equation along system trajectories while ensuring the closed-loop stability. Local uniformly ultimate boundedness of the closed-loop system is verified by using Lyapunov theory. The performance of the proposed controller is verified via simulation on an unstable coupled diffusion reaction process.

  7. A method of recovering the initial vectors of globally coupled map lattices based on symbolic dynamics

    International Nuclear Information System (INIS)

    Sun Li-Sha; Kang Xiao-Yun; Zhang Qiong; Lin Lan-Xin

    2011-01-01

    Based on symbolic dynamics, a novel computationally efficient algorithm is proposed to estimate the unknown initial vectors of globally coupled map lattices (CMLs). It is proved that not all inverse chaotic mapping functions are satisfied for contraction mapping. It is found that the values in phase space do not always converge on their initial values with respect to sufficient backward iteration of the symbolic vectors in terms of global convergence or divergence (CD). Both CD property and the coupling strength are directly related to the mapping function of the existing CML. Furthermore, the CD properties of Logistic, Bernoulli, and Tent chaotic mapping functions are investigated and compared. Various simulation results and the performances of the initial vector estimation with different signal-to-noise ratios (SNRs) are also provided to confirm the proposed algorithm. Finally, based on the spatiotemporal chaotic characteristics of the CML, the conditions of estimating the initial vectors using symbolic dynamics are discussed. The presented method provides both theoretical and experimental results for better understanding and characterizing the behaviours of spatiotemporal chaotic systems. (general)

  8. A method of recovering the initial vectors of globally coupled map lattices based on symbolic dynamics

    Science.gov (United States)

    Sun, Li-Sha; Kang, Xiao-Yun; Zhang, Qiong; Lin, Lan-Xin

    2011-12-01

    Based on symbolic dynamics, a novel computationally efficient algorithm is proposed to estimate the unknown initial vectors of globally coupled map lattices (CMLs). It is proved that not all inverse chaotic mapping functions are satisfied for contraction mapping. It is found that the values in phase space do not always converge on their initial values with respect to sufficient backward iteration of the symbolic vectors in terms of global convergence or divergence (CD). Both CD property and the coupling strength are directly related to the mapping function of the existing CML. Furthermore, the CD properties of Logistic, Bernoulli, and Tent chaotic mapping functions are investigated and compared. Various simulation results and the performances of the initial vector estimation with different signal-to-noise ratios (SNRs) are also provided to confirm the proposed algorithm. Finally, based on the spatiotemporal chaotic characteristics of the CML, the conditions of estimating the initial vectors using symbolic dynamics are discussed. The presented method provides both theoretical and experimental results for better understanding and characterizing the behaviours of spatiotemporal chaotic systems.

  9. 1,3-Dipolar cycloaddition reactions of nitrile oxides in the synthesis of natural compounds and their analogues

    International Nuclear Information System (INIS)

    Kotyatkina, Anna I; Zhabinsky, Vladimir N; Khripach, Vladimir A

    2001-01-01

    The published data on the use of 1,3-dipolar cycloaddition reactions of nitrile oxides in the synthesis of natural compounds and their analogues are systematised and reviewed. The bibliography includes 145 references.

  10. Synchronization of random bit generators based on coupled chaotic lasers and application to cryptography.

    Science.gov (United States)

    Kanter, Ido; Butkovski, Maria; Peleg, Yitzhak; Zigzag, Meital; Aviad, Yaara; Reidler, Igor; Rosenbluh, Michael; Kinzel, Wolfgang

    2010-08-16

    Random bit generators (RBGs) constitute an important tool in cryptography, stochastic simulations and secure communications. The later in particular has some difficult requirements: high generation rate of unpredictable bit strings and secure key-exchange protocols over public channels. Deterministic algorithms generate pseudo-random number sequences at high rates, however, their unpredictability is limited by the very nature of their deterministic origin. Recently, physical RBGs based on chaotic semiconductor lasers were shown to exceed Gbit/s rates. Whether secure synchronization of two high rate physical RBGs is possible remains an open question. Here we propose a method, whereby two fast RBGs based on mutually coupled chaotic lasers, are synchronized. Using information theoretic analysis we demonstrate security against a powerful computational eavesdropper, capable of noiseless amplification, where all parameters are publicly known. The method is also extended to secure synchronization of a small network of three RBGs.

  11. Coupled-Inductor-Based Aalborg Inverter With Input DC Energy Regulation

    DEFF Research Database (Denmark)

    Wang, Houqing; Wu, Weimin; Chung, Henry Shu-hung

    2018-01-01

    Due to the global environmental issues and energy crisis, the injection of renewable energy sources (RESs) into the power system is continuously increasing. As the interface between RESs and power grid, grid-tied inverters using MOSFET switches, without traditional line frequency transformers, show...... some potential advantages, in terms of low cost, high efficiency, and lightweight and small size. Among several proposed configurations, the Aalborg inverter was proposed as a new family of high efficiency MOSFET-switch-based hybrid source inverters. For a conventional “half bridge” type Aalborg...... inverter, due to the imbalance of two independent dc sources, the input dc energies may not be fully utilized, which may reduce the efficiency of whole system. In order to extract the maximum energy from two independent dc sources, a coupled-inductor-based “half bridge” type Aalborg inverter is proposed...

  12. Coupled thermomechanical behavior of graphene using the spring-based finite element approach

    Energy Technology Data Exchange (ETDEWEB)

    Georgantzinos, S. K., E-mail: sgeor@mech.upatras.gr; Anifantis, N. K., E-mail: nanif@mech.upatras.gr [Machine Design Laboratory, Department of Mechanical Engineering and Aeronautics, University of Patras, Rio, 26500 Patras (Greece); Giannopoulos, G. I., E-mail: ggiannopoulos@teiwest.gr [Materials Science Laboratory, Department of Mechanical Engineering, Technological Educational Institute of Western Greece, 1 Megalou Alexandrou Street, 26334 Patras (Greece)

    2016-07-07

    The prediction of the thermomechanical behavior of graphene using a new coupled thermomechanical spring-based finite element approach is the aim of this work. Graphene sheets are modeled in nanoscale according to their atomistic structure. Based on molecular theory, the potential energy is defined as a function of temperature, describing the interatomic interactions in different temperature environments. The force field is approached by suitable straight spring finite elements. Springs simulate the interatomic interactions and interconnect nodes located at the atomic positions. Their stiffness matrix is expressed as a function of temperature. By using appropriate boundary conditions, various different graphene configurations are analyzed and their thermo-mechanical response is approached using conventional finite element procedures. A complete parametric study with respect to the geometric characteristics of graphene is performed, and the temperature dependency of the elastic material properties is finally predicted. Comparisons with available published works found in the literature demonstrate the accuracy of the proposed method.

  13. Autonomous quantum Maxwell's demon based on two exchange-coupled quantum dots

    Science.gov (United States)

    Ptaszyński, Krzysztof

    2018-01-01

    I study an autonomous quantum Maxwell's demon based on two exchange-coupled quantum dots attached to the spin-polarized leads. The principle of operation of the demon is based on the coherent oscillations between the spin states of the system which act as a quantum iSWAP gate. Due to the operation of the iSWAP gate, one of the dots acts as a feedback controller which blocks the transport with the bias in the other dot, thus inducing the electron pumping against the bias; this leads to the locally negative entropy production. Operation of the demon is associated with the information transfer between the dots, which is studied quantitatively by mapping the analyzed setup onto the thermodynamically equivalent auxiliary system. The calculated entropy production in a single subsystem and information flow between the subsystems are shown to obey a local form of the second law of thermodynamics, similar to the one previously derived for classical bipartite systems.

  14. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    Science.gov (United States)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1H/1H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  15. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    International Nuclear Information System (INIS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-01-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1 H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1 H/ 1 H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials

  16. Multicomponent synthesis of spiropyrrolidine analogues derived from vinylindole/indazole by a 1,3-dipolar cycloaddition reaction

    Directory of Open Access Journals (Sweden)

    Manjunatha Narayanarao

    2016-12-01

    Full Text Available A new series of spiropyrrolidine compounds containing indole/indazole moieties as side chains have been accomplished via a one-pot multicomponent synthesis. The method uses the 1,3-dipolar cycloaddition reaction between N-alkylvinylindole/indazole and azomethine ylides, prepared in situ from cyclic/acyclic amino acids. The 1,3-dipolar cycloaddition proceeds efficiently under thermal conditions to afford the regio- and stereospecific cyclic adducts.

  17. Arrays of dipolar molecular rotors in Tris(o-phenylenedioxy) cyclotriphosphazene.

    Science.gov (United States)

    Zhao, Ke; Dron, Paul I; Kaleta, Jiří; Rogers, Charles T; Michl, Josef

    2014-01-01

    Regular two-dimensional or three-dimensional arrays of mutually interacting dipolar molecular rotors represent a worthy synthetic objective. Their dielectric properties, including possible collective behavior, will be a sensitive function of the location of the rotors, the orientation of their axes, and the size of their dipoles. Host-guest chemistry is one possible approach to gaining fine control over these factors. We describe the progress that has been achieved in recent years using tris (o-phenylenedioxy)cyclotriphosphazene as a host and a series of rod-shaped dipolar molecular rotors as guests. Structures of both surface and bulk inclusion compounds have been established primarily by solid-state nuclear magnetic resonance (NMR) and powder X-ray diffraction (XRD) techniques. Low-temperature dielectric spectroscopy revealed rotational barriers as low as 1.5 kcal/mol, but no definitive evidence for collective behavior has been obtained so far.

  18. Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Byrnes, Christian [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Domènech, Guillem; Sasaki, Misao [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Takahashi, Tomo, E-mail: C.Byrnes@sussex.ac.uk, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: tomot@cc.saga-u.ac.jp [Department of Physics, Saga University, Saga 840-8502 (Japan)

    2016-12-01

    We reconsider the observed CMB dipolar asymmetry in the context of open inflation, where a supercurvature mode might survive the bubble nucleation. If such a supercurvature mode modulates the amplitude of the curvature power spectrum, it would easily produce an asymmetry in the power spectrum. We show that current observational data can be accommodated in a three-field model, with simple quadratic potentials and a non-trivial field-space metric. Despite the presence of three fields, we believe this model is so far the simplest that can match current observations. We are able to match the observed strong scale dependence of the dipolar asymmetry, without a fine tuning of initial conditions, breaking slow roll or adding a feature to the evolution of any field.

  19. Quantum-well exciton dipolar interaction: Polarization-dependence and Z-LT splitting

    International Nuclear Information System (INIS)

    Nguyen Ba An.

    1996-12-01

    We calculate the exciton dipolar interaction in a semiconductor quantum well. The explicit polarization-dependence, i.e, the dependence on both the exciton dipole moment μ-vector and its inplane wavevector k-vector is derived. The obtained results for the three modes (L, T and Z modes) of the long-range part of the dipolar interaction satisfy the polarization sum rule for any parameters. In the long wavelength limit there is a Z-LT splitting which decreases as the well width increases reflecting a crossover from strict 2D to quasi-2D. A rough crossover from quasi-2D to 3D is also described. (author). 18 refs, 4 figs

  20. Critical behaviour of nanocrystalline gadolinium: evidence for random uniaxial dipolar universality class

    International Nuclear Information System (INIS)

    Ferdinand, A; Probst, A-C; Birringer, R; Michels, A; Kaul, S N

    2014-01-01

    We report on how nanocrystal size affects the critical behaviour of the rare-earth metal Gd near the ferromagnetic-to-paramagnetic phase transition. The asymptotic critical behaviour of the coarse-grained polycrystalline sample (with an average crystallite size of L≅100 μm) is that of a (pure) uniaxial dipolar ferromagnet, as is the case with single crystal Gd, albeit the width of the asymptotic critical region (ACR) is reduced. As the grain size approaches ∼30 nm, the ACR is so narrow that it could not be accessed in the present experiments. Inaccessibly narrow ACR for L ∼ 30 nm and continuous increase in the width of the ACR as L decreases from 16 to 9.5 nm basically reflect a crossover to the random uniaxial dipolar fixed point caused by the quenched random exchange disorder prevalent at the internal interfaces (grain boundaries). (paper)

  1. Modelling and analysis of transient state during improved coupling procedure with the grid for DFIG based wind turbine generator

    Science.gov (United States)

    Kammoun, Soulaymen; Sallem, Souhir; Ben Ali Kammoun, Mohamed

    2017-11-01

    The aim of this study is to enhance DFIG based Wind Energy Conversion Systems (WECS) dynamics during grid coupling. In this paper, a system modelling and a starting/coupling procedure for this generator to the grid are proposed. The proposed non-linear system is a variable structure system (VSS) and has two different states, before and after coupling. So, two different state models are given to the system to analyse transient stability during the coupling. The given model represents well the transient state of the machine, through which, a behaviour assessment of the generator before, during and after connection is given based on simulation results. For this, a 300 kW DFIG based wind generation system model was simulated on the Matlab/SIMULINK environment. We judge the proposed procedure to be practical, smooth and stability improved.

  2. Sequential and base rate analysis of emotional validation and invalidation in chronic pain couples: patient gender matters.

    Science.gov (United States)

    Leong, Laura E M; Cano, Annmarie; Johansen, Ayna B

    2011-11-01

    The purpose of this study was to examine the extent to which communication patterns that foster or hinder intimacy and emotion regulation in couples were related to pain, marital satisfaction, and depression in 78 chronic pain couples attempting to problem-solve an area of disagreement in their marriage. Sequences and base rates of validation and invalidation communication patterns were almost uniformly unrelated to adjustment variables unless patient gender was taken into account. Male patient couples' reciprocal invalidation was related to worse pain, but this was not found in female patient couples. In addition, spouses' validation was related to poorer patient pain and marital satisfaction, but only in couples with a male patient. It was not only the presence or absence of invalidation and validation that mattered (base rates), but the context and timing of these events (sequences) that affected patients' adjustment. This research demonstrates that sequences of interaction behaviors that foster and hinder emotion regulation should be attended to when assessing and treating pain patients and their spouses. This article presents analyses of both sequences and base rates of chronic pain couples' communication patterns, focusing on validation and invalidation. These results may potentially improve psychosocial treatments for these couples, by addressing sequential interactions of intimacy and empathy. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

  3. Coupled behavior of shape memory alloy-based morphing spacecraft radiators: experimental assessment and analysis

    Science.gov (United States)

    Bertagne, C.; Walgren, P.; Erickson, L.; Sheth, R.; Whitcomb, J.; Hartl, D.

    2018-06-01

    Thermal control is an important aspect of spacecraft design, particularly in the case of crewed vehicles, which must maintain a precise internal temperature at all times in spite of significant variations in the external thermal environment and internal heat loads. Future missions beyond low Earth orbit will require radiator systems with high turndown ratios, defined as the ratio between the maximum and minimum heat rejection rates achievable by the radiator system. Current radiators are only able to achieve turndown ratios of 3:1, far less than the 12:1 turndown ratio requirement expected for future missions. An innovative morphing radiator concept uses the temperature-induced phase transformation of shape memory alloy (SMA) materials to achieve turndown ratios that are predicted to exceed 12:1 via substantial geometric reconfiguration. Developing mathematical and computational models of these morphing radiators is challenging due to the strong two-way thermomechanical coupling not present in traditional fixed-geometry radiators and not widely considered in the literature. Although existing simulation tools are capable of analyzing the behavior of some thermomechanically coupled structures, general problems involving radiation and deformation cannot be modeled using publicly available codes due to the complexity of modeling spatially evolving boundary fields. This paper provides important insight into the operational response of SMA-based morphing radiators by employing computational tools developed to overcome previous shortcomings. Several example problems are used to demonstrate the novel radiator concept. Additionally, a prototype morphing radiator was designed, fabricated, and tested in a thermal environment compatible with mission operations. An associated finite element model of the prototype was developed and executed. Model predictions of radiator performance generally agree with the experimental data, giving confidence that the tools developed are able

  4. A hybrid algorithm for coupling partial differential equation and compartment-based dynamics.

    Science.gov (United States)

    Harrison, Jonathan U; Yates, Christian A

    2016-09-01

    Stochastic simulation methods can be applied successfully to model exact spatio-temporally resolved reaction-diffusion systems. However, in many cases, these methods can quickly become extremely computationally intensive with increasing particle numbers. An alternative description of many of these systems can be derived in the diffusive limit as a deterministic, continuum system of partial differential equations (PDEs). Although the numerical solution of such PDEs is, in general, much more efficient than the full stochastic simulation, the deterministic continuum description is generally not valid when copy numbers are low and stochastic effects dominate. Therefore, to take advantage of the benefits of both of these types of models, each of which may be appropriate in different parts of a spatial domain, we have developed an algorithm that can be used to couple these two types of model together. This hybrid coupling algorithm uses an overlap region between the two modelling regimes. By coupling fluxes at one end of the interface and using a concentration-matching condition at the other end, we ensure that mass is appropriately transferred between PDE- and compartment-based regimes. Our methodology gives notable reductions in simulation time in comparison with using a fully stochastic model, while maintaining the important stochastic features of the system and providing detail in appropriate areas of the domain. We test our hybrid methodology robustly by applying it to several biologically motivated problems including diffusion and morphogen gradient formation. Our analysis shows that the resulting error is small, unbiased and does not grow over time. © 2016 The Authors.

  5. Radiant floor cooling coupled with dehumidification systems in residential buildings: A simulation-based analysis

    International Nuclear Information System (INIS)

    Zarrella, Angelo; De Carli, Michele; Peretti, Clara

    2014-01-01

    Highlights: • The floor radiant cooling in a typical apartment is analyzed. • Dehumidification devices, fan-coil and mechanical ventilation are compared. • The results are analyzed in terms of both thermal comfort and energy consumption. • The energy consumption of the dehumidifiers is higher than that of other systems. • The mechanical ventilation decreases the moisture level better than other systems. - Abstract: The development of radiant cooling has stimulated an interest in new systems based on coupling ventilation with radiant cooling. However, radiant cooling systems may cause condensation to form on an active surface under warm and humid conditions during the cooling season. This phenomenon occurs when surface temperature falls below dew point. To prevent condensation, air humidity needs to be reduced with a dehumidification device or a mechanical ventilation system. There are two main options to achieve this. The first is to use dehumidification devices that reduce humidity, but are not coupled with ventilation, i.e. devices that handle room air and leave air change to infiltrations. The second is to combine a mechanical ventilation system with dehumidifying finned coils. This study analyzes the floor radiant cooling of a typical residential apartment within a multi-storey building in three Italian climate zones by means of a detailed simulation tool. Five systems were compared in terms of both indoor thermal comfort and energy consumption: radiant cooling without dehumidification; radiant cooling with a soft dehumidification device; radiant cooling with a dehumidification device which also supplies sensible cooling; radiant cooling coupled with fan coils; and radiant cooling with a mechanical ventilation system which dehumidifies and cools

  6. Formulation based on artificial neural network of thermodynamic properties of ozone friendly refrigerant/absorbent couples

    International Nuclear Information System (INIS)

    Soezen, Adnan; Arcaklioglu, Erol; Oezalp, Mehmet

    2005-01-01

    This paper presents a new approach based on artificial neural networks (ANNs) to determine the properties of liquid and two phase boiling and condensing of two alternative refrigerant/absorbent couples (methanol/LiBr and methanol/LiCl). These couples do not cause ozone depletion and use in the absorption thermal systems (ATSs). ANNs are able to learn the key information patterns within multidimensional information domain. ANNs operate such as a 'black box' model, requiring no detailed information about the system. On the other hand, they learn the relationship between the input and the output. In order to train the neural network, limited experimental measurements were used as training data and test data. In this study, in input layer, there are temperatures in the range of 298-498 K, pressures (0.1-40 MPa) and concentrations of 2%, 7%, 12% of the couples; specific volume is in output layer. The back-propagation learning algorithm with three different variants, namely scaled conjugate gradient (SCG), Pola-Ribiere conjugate gradient (CGP), and Levenberg-Marquardt (LM), and logistic sigmoid transfer function were used in the network so that the best approach can find. The most suitable algorithm and neuron number in the hidden layer are found as SCG with 8 neurons. For this number level, after the training, it is found that maximum error is less than 3%, average error is about 1% and R 2 value are 99.999%. As seen from the results obtained the thermodynamic equations for each pair by using the weights of network have been obviously predicted within acceptable errors. This paper shows that values predicted with ANN can be used to define the thermodynamic properties instead of approximate and complex analytic equations

  7. Silicon-Nitride-based Integrated Optofluidic Biochemical Sensors using a Coupled-Resonator Optical Waveguide

    Directory of Open Access Journals (Sweden)

    Jiawei eWANG

    2015-04-01

    Full Text Available Silicon nitride (SiN is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU, with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.

  8. Bound states of Dipolar Bosons in One-dimensional Systems

    DEFF Research Database (Denmark)

    G. Volosniev, A.; R. Armstrong, J.; V. Fedorov, D.

    2013-01-01

    that in the weakly-coupled limit the inter-tube interaction is similar to a zero-range term with a suitable rescaled strength. This allows us to address the corresponding many-body physics of the system by constructing a model where bound chains with one molecule in each tube are the effective degrees of freedom......We consider one-dimensional tubes containing bosonic polar molecules. The long-range dipole-dipole interactions act both within a single tube and between different tubes. We consider arbitrary values of the externally aligned dipole moments with respect to the symmetry axis of the tubes. The few....... This model can be mapped onto one-dimensional Hamiltonians for which exact solutions are known....

  9. Home-Based HIV Testing and Counseling for Male Couples (Project Nexus): A Protocol for a Randomized Controlled Trial.

    Science.gov (United States)

    Stephenson, Rob; Freeland, Ryan; Sullivan, Stephen P; Riley, Erin; Johnson, Brent A; Mitchell, Jason; McFarland, Deborah; Sullivan, Patrick S

    2017-05-30

    HIV prevalence remains high among men who have sex with men (MSM) in the United States, yet the majority of research has focused on MSM as individuals, not as dyads, and has discussed HIV risks primarily in the context of casual sex. Nexus is an online prevention program that combines home-based HIV testing and couples HIV testing and counseling (CHTC). It allows partners in dyadic MSM relationships to receive HIV testing and care in the comfort of their designated residence, via video-based chat. By using video-based technologies (eg, VSee video chat), male couples receive counseling and support from a remote online counselor, while testing for HIV at home. This randomized control trial (RCT) aims to examine the effects of video-based counseling combined with home-based HIV testing on couples' management of HIV risk, formation and adherence to explicit sexual agreements, and sexual risk-taking. The research implements a prospective RCT of 400 online-recruited male couples: 200 self-reported concordant-negative couples and 200 self-reported discordant couples. Couples in the control arm will receive one or two home-based HIV self-testing kits and will be asked to report their results via the study's website. Couples in the experimental arm will receive one or two home-based HIV self-testing kits and will conduct these tests together under the facilitation of a remotely located counselor during a prescheduled VSee-based video CHTC session. Study assessments are taken at baseline, as well as at 3- and 6-month follow-up sessions. Project Nexus was launched in April 2016 and is ongoing. To date, 219 eligible couples have been enrolled and randomized. Combining home-based HIV testing with video-based counseling creates an opportunity to expand CHTC to male couples who (1) live outside metro areas, (2) live in rural areas without access to testing services or LGBTQ resources, or (3) feel that current clinic-based testing is not for them (eg, due to fears of

  10. A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

    International Nuclear Information System (INIS)

    Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh; Hamzehloueian, Mahshid; Alimohammadi, Kamal

    2013-01-01

    An efficient one-pot three-component procedure for the synthesis of novel spiroacenaphthene pyrroloisoquinolines with high regioselectivity is described. These compounds were prepared from 1,3-dipolar cycloaddition of an azomethine ylide generated from acenaphthenequinone and 1,2,3,4-tetrahydroisoquinoline via [1,5]-H shift, with chalcone and nitrostyrene derivatives as dipolarophiles. The structure and stereochemistry of the cycloadducts have been established by single crystal X-ray structure and spectroscopic techniques. (author)

  11. Scaling parallels in the non-Debye dielectric relaxation of ionic glasses and dipolar supercooled liquids

    International Nuclear Information System (INIS)

    Sidebottom, D.L.; Green, P.F.; Brow, R.K.

    1997-01-01

    We compare the dielectric response of ionic glasses and dipolar liquids near the glass transition. Our work is divided into two parts. In the first section we examine ionic glasses and the two prominent approaches to analyzing the dielectric response. The conductivity of ion-conducting glasses displays a power law dispersion σ(ω)∝ω n , where n∼0.67, but frequently the dielectric response is analyzed using the electrical modulus M * (ω)=1/var-epsilon * (ω), where var-epsilon * (ω)=var-epsilon(ω)-iσ(ω)/ω is the complex permittivity. We reexamine two specific examples where the shape of M * (ω) changes in response to changes in (a) temperature and (b) ion concentration, to suggest fundamental changes in ion dynamics are occurring. We show, however, that these changes in the shape of M * (ω) occur in the absence of changes in the scaling properties of σ(ω), for which n remains constant. In the second part, we examine the dielectric relaxation found in dipolar liquids, for which var-epsilon * (ω) likewise exhibits changes in shape on approach to the glass transition. Guided by similarities of M * (ω) in ionic glasses and var-epsilon * (ω) in dipolar liquids, we demonstrate that a recent scaling approach proposed by Dixon and co-workers for var-epsilon * (ω) of dipolar relaxation also appears valid for M * (ω) in the ionic case. While this suggests that the Dixon scaling approach is more universal than previously recognized, we demonstrate how the dielectric response can be scaled in a linear manner using an alternative data representation. copyright 1997 The American Physical Society

  12. Enantioselective 1,3-dipolar cycloadditions of diazoacetates with electron-deficient olefins.

    Science.gov (United States)

    Sibi, Mukund P; Stanley, Levi M; Soeta, Takahiro

    2007-04-12

    [reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyrazolines with excellent enantioselectivities. Finally, an efficient synthesis of (-)-manzacidin A employing this cycloaddition methodology as a key step is illustrated.

  13. NMR studies on 1,3-dipolar cycloaddition of nitrile oxides to norbornenes

    International Nuclear Information System (INIS)

    Gucma, Mirosław; Gołębiewski, W. Marek; Krawczyk, Maria

    2013-01-01

    The 1,3-dipolar cycloaddition reaction of nitrile oxides to norbornenes substituted with an acrylate-derived moiety was examined. Only adducts to norbornene system were formed with a good exo selectivity and complete site-selectivity. Structures of the products were elucidated by an extensive application of electrospray ionization-mass spectrometry (ESI-MS) and 2D 1 H and 13 C nuclear magnetic resonance (NMR). (author)

  14. The role of magnetic field fluctuations in nonadiabatic acceleration of ions during dipolarization

    Science.gov (United States)

    Ono, Y.; Nosé, M.; Christon, S. P.; Lui, A. T. Y.

    2009-05-01

    We statistically examine changes in the composition of two different ion species, proton and oxygen ions, in the near-Earth plasma sheet (X = -16 R E ˜ -6 R E ) during substorm-associated dipolarization. We use 10 years of energetic (9-212 keV/e) ion data obtained by the suprathermal ion composition spectrometer (STICS) sensor of the energetic particles and ion composition (EPIC) instrument on board the Geotail spacecraft. The results are as follows: (1) Although the percentage increase in the energy density of O+ ions before and after a dipolarization exceeds that of H+ ions in the low-energy range (9-36 keV/e), this property is not evident in the high-energy range (56-212 keV/e); (2) the energy spectrum of H+ and that of O+ become harder after dipolarization in almost all events; and (3) in some events the energy spectrum of O+ becomes harder than that of H+ as reported by previous studies, and, importantly, in other events, the spectrum of H+ becomes harder than that of O+. In order to investigate what mechanism causes these observational results, we focus on magnetic field fluctuations during dipolarization. It is found that the increase of the spectrum slope is positively correlated with the power of waves whose frequencies are close to the gyrofrequency of H+ or O+, respectively (the correlation coefficient is 0.48 for H+ and 0.68 for O+). In conclusion, ions are nonadiabatically accelerated by the electric field induced by the magnetic field fluctuations whose frequencies are close to their gyrofrequencies.

  15. Long-range dipolar order and dispersion forces in polar liquids

    Science.gov (United States)

    Besford, Quinn Alexander; Christofferson, Andrew Joseph; Liu, Maoyuan; Yarovsky, Irene

    2017-11-01

    Complex solvation phenomena, such as specific ion effects, occur in polar liquids. Interpretation of these effects in terms of structure and dispersion forces will lead to a greater understanding of solvation. Herein, using molecular dynamics, we probe the structure of polar liquids through specific dipolar pair correlation functions that contribute to the potential of mean force that is "felt" between thermally rotating dipole moments. It is shown that unique dipolar order exists at separations at least up to 20 Å for all liquids studied. When the structural order is compared with a dipolar dispersion force that arises from local co-operative enhancement of dipole moments, a strong agreement is found. Lifshitz theory of dispersion forces was compared with the structural order, where the theory is validated for all liquids that do not have significant local dipole correlations. For liquids that do have significant local dipole correlations, specifically liquid water, Lifshitz theory underestimates the dispersion force by a factor of 5-10, demonstrating that the force that leads to the increased structure in liquid water is missed by Lifshitz theory of van der Waals forces. We apply similar correlation functions to an ionic aqueous system, where long-range order between water's dipole moment and a single chloride ion is found to exist at 20 Å of separation, revealing a long-range perturbation of water's structure by an ion. Furthermore, we found that waters within the 1st, 2nd, and 3rd solvation shells of a chloride ion exhibit significantly enhanced dipolar interactions, particularly with waters at larger distances of separation. Our results provide a link between structures, dispersion forces, and specific ion effects, which may lead to a more robust understanding of solvation.

  16. NMR studies on 1,3-dipolar cycloaddition of nitrile oxides to norbornenes

    Energy Technology Data Exchange (ETDEWEB)

    Gucma, Miroslaw; Golebiewski, W. Marek; Krawczyk, Maria, E-mail: golebiewski@ipo.waw.pl [Institute of Industrial Organic Chemistry, Warsaw (Poland)

    2013-05-15

    The 1,3-dipolar cycloaddition reaction of nitrile oxides to norbornenes substituted with an acrylate-derived moiety was examined. Only adducts to norbornene system were formed with a good exo selectivity and complete site-selectivity. Structures of the products were elucidated by an extensive application of electrospray ionization-mass spectrometry (ESI-MS) and 2D {sup 1}H and {sup 13}C nuclear magnetic resonance (NMR). (author)

  17. Observation of plasmonic dipolar anti-bonding mode in silver nanoring structures

    International Nuclear Information System (INIS)

    Ye Jian; Van Dorpe, Pol; Lagae, Liesbet; Borghs, Gustaaf; Maes, Guido

    2009-01-01

    We report on a clear experimental observation of the plasmonic dipolar anti-bonding resonance in silver nanorings. The data can be explained effectively by the plasmon hybridization model, which is confirmed by the numerical calculations of the electromagnetic field and surface charge distribution profiles. The experimental demonstration of the plasmon hybridization model indicates its usefulness as a valuable tool to understand, design and predict optical properties of metallic nanostructures.

  18. Observation of plasmonic dipolar anti-bonding mode in silver nanoring structures

    Energy Technology Data Exchange (ETDEWEB)

    Ye Jian; Van Dorpe, Pol; Lagae, Liesbet; Borghs, Gustaaf [Interuniversity Microelectronics Center (IMEC), Kapeldreef 75, B-3001 Leuven (Belgium); Maes, Guido, E-mail: Jian.Ye@imec.b [Chemistry Department, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, B-3001 Leuven (Belgium)

    2009-11-18

    We report on a clear experimental observation of the plasmonic dipolar anti-bonding resonance in silver nanorings. The data can be explained effectively by the plasmon hybridization model, which is confirmed by the numerical calculations of the electromagnetic field and surface charge distribution profiles. The experimental demonstration of the plasmon hybridization model indicates its usefulness as a valuable tool to understand, design and predict optical properties of metallic nanostructures.

  19. Observation of plasmonic dipolar anti-bonding mode in silver nanoring structures

    Science.gov (United States)

    Ye, Jian; Van Dorpe, Pol; Lagae, Liesbet; Maes, Guido; Borghs, Gustaaf

    2009-11-01

    We report on a clear experimental observation of the plasmonic dipolar anti-bonding resonance in silver nanorings. The data can be explained effectively by the plasmon hybridization model, which is confirmed by the numerical calculations of the electromagnetic field and surface charge distribution profiles. The experimental demonstration of the plasmon hybridization model indicates its usefulness as a valuable tool to understand, design and predict optical properties of metallic nanostructures.

  20. A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh, E-mail: ysarrafi@umz.ac.ir [Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran (Iran, Islamic Republic of); Hamzehloueian, Mahshid [Department of Chemistry, Jouybar Branch, Islamic Azad University, Jouybar (Iran, Islamic Republic of); Alimohammadi, Kamal [Department of Chemistry, Dr. Shariati Branch, University of Farhangian, Sari (Iran, Islamic Republic of)

    2013-12-01

    An efficient one-pot three-component procedure for the synthesis of novel spiroacenaphthene pyrroloisoquinolines with high regioselectivity is described. These compounds were prepared from 1,3-dipolar cycloaddition of an azomethine ylide generated from acenaphthenequinone and 1,2,3,4-tetrahydroisoquinoline via [1,5]-H shift, with chalcone and nitrostyrene derivatives as dipolarophiles. The structure and stereochemistry of the cycloadducts have been established by single crystal X-ray structure and spectroscopic techniques. (author)

  1. AQUASOL: An efficient solver for the dipolar Poisson-Boltzmann-Langevin equation.

    Science.gov (United States)

    Koehl, Patrice; Delarue, Marc

    2010-02-14

    The Poisson-Boltzmann (PB) formalism is among the most popular approaches to modeling the solvation of molecules. It assumes a continuum model for water, leading to a dielectric permittivity that only depends on position in space. In contrast, the dipolar Poisson-Boltzmann-Langevin (DPBL) formalism represents the solvent as a collection of orientable dipoles with nonuniform concentration; this leads to a nonlinear permittivity function that depends both on the position and on the local electric field at that position. The differences in the assumptions underlying these two models lead to significant differences in the equations they generate. The PB equation is a second order, elliptic, nonlinear partial differential equation (PDE). Its response coefficients correspond to the dielectric permittivity and are therefore constant within each subdomain of the system considered (i.e., inside and outside of the molecules considered). While the DPBL equation is also a second order, elliptic, nonlinear PDE, its response coefficients are nonlinear functions of the electrostatic potential. Many solvers have been developed for the PB equation; to our knowledge, none of these can be directly applied to the DPBL equation. The methods they use may adapt to the difference; their implementations however are PBE specific. We adapted the PBE solver originally developed by Holst and Saied [J. Comput. Chem. 16, 337 (1995)] to the problem of solving the DPBL equation. This solver uses a truncated Newton method with a multigrid preconditioner. Numerical evidences suggest that it converges for the DPBL equation and that the convergence is superlinear. It is found however to be slow and greedy in memory requirement for problems commonly encountered in computational biology and computational chemistry. To circumvent these problems, we propose two variants, a quasi-Newton solver based on a simplified, inexact Jacobian and an iterative self-consistent solver that is based directly on the PBE

  2. Absence of Long-Range Order in a Triangular Spin System with Dipolar Interactions

    Science.gov (United States)

    Keleş, Ahmet; Zhao, Erhai

    2018-05-01

    The antiferromagnetic Heisenberg model on the triangular lattice is perhaps the best known example of frustrated magnets, but it orders at low temperatures. Recent density matrix renormalization group (DMRG) calculations find that the next nearest neighbor interaction J2 enhances the frustration, and it leads to a spin liquid for J2/J1∈(0.08 ,0.15 ). In addition, a DMRG study of a dipolar Heisenberg model with longer range interactions gives evidence for a spin liquid at a small dipole tilting angle θ ∈[0 ,1 0 ° ). In both cases, the putative spin liquid region appears to be small. Here, we show that for the triangular lattice dipolar Heisenberg model, a robust quantum paramagnetic phase exists in a surprisingly wide region, θ ∈[0 ,5 4 ° ) , for dipoles tilted along the lattice diagonal direction. We obtain the phase diagram of the model by functional renormalization group (RG), which treats all magnetic instabilities on equal footing. The quantum paramagnetic phase is characterized by a smooth continuous flow of vertex functions and spin susceptibility down to the lowest RG scale, in contrast to the apparent breakdown of RG flow in phases with stripe or spiral order. Our finding points to a promising direction to search for quantum spin liquids in ultracold dipolar molecules.

  3. Topological defect formation in rotating binary dipolar Bose–Einstein condensate

    International Nuclear Information System (INIS)

    Zhang, Xiao-Fei; Han, Wei; Jiang, Hai-Feng; Liu, Wu-Ming; Saito, Hiroki; Zhang, Shou-Gang

    2016-01-01

    We investigate the topological defects and spin structures of a rotating binary Bose–Einstein condensate, which consists of both dipolar and scalar bosonic atoms confined in spin-dependent optical lattices, for an arbitrary orientation of the dipoles with respect to their plane of motion. Our results show that the tunable dipolar interaction, especially the orientation of the dipoles, can be used to control the direction of stripe phase and its related half-vortex sheets. In addition, it can also be used to obtain a regular arrangement of various topological spin textures, such as meron, circular and cross disgyration spin structures. We point out that such topological defects and regular arrangement of spin structures arise primarily from the long-range and anisotropic nature of dipolar interaction and its competition with the spin-dependent optical lattices and rotation. - Highlights: • Effects of both strength and orientation of the dipoles are discussed. • Various topological defects can be formed in different parameter regions. • Present one possible way to obtain regular arrangements of spin textures.

  4. Bose-Einstein condensation and study of inelastic collisions due to dipolar interactions

    International Nuclear Information System (INIS)

    Beaufils, Q.

    2009-01-01

    Its large magnetic moment in the ground state makes chromium a good candidate for the study of dipolar interactions in a degenerate gas. We have built an experimental setup for trapping and cooling atoms of "5"2Cr down to Bose-Einstein condensation (BEC). Evaporative cooling takes place in a purely optical trap, which is loaded from the magneto-optical trap using a novel process of continuous accumulation of metastable states. We produce a condensate of typically 15000 atoms in a time of 15 s. We have studied the possibility to bring all the Zeeman substates of a chromium BEC to degeneracy in a non-zero static magnetic field, using a radiofrequency (rf) magnetic field, and demonstrated a new process of rf-assisted dipolar relaxation. We have also studied a narrow Feshbach resonance induced by dipolar interaction, which implies a d-wave collisional channel. We analyzed this resonance in the presence of a rf magnetic field and we reinterpreted rf association of molecules as a mere Feshbach resonance between rf dressed states. Finally, we have set up an optical lattice in the perspective of studying the effects of dipole-dipole interactions in reduced dimension. (author)

  5. Nonlinear localized modes in dipolar Bose-Einstein condensates in optical lattices

    International Nuclear Information System (INIS)

    Rojas-Rojas, S.; Vicencio, R. A.; Molina, M. I.; Abdullaev, F. Kh.

    2011-01-01

    Modulational instability and discrete matter wave solitons in dipolar BECs, loaded into a deep optical lattice, are investigated analytically and numerically. The process of modulational instability of nonlinear plane matter waves in a dipolar nonlinear lattice is studied and the regions of instability are established. The existence and stability of bulk discrete solitons are analyzed analytically and confirmed by numerical simulations. In marked contrast with the usual discrete nonlinear Schroedinger behavior (no dipolar interactions), we found a region where the two fundamental modes are simultaneously unstable, allowing enhanced mobility across the lattice for large norm values. To study the existence and properties of surface discrete solitons, an analysis of the dimer configuration is performed. The properties of symmetric and antisymmetric modes including stability diagrams and bifurcations are investigated in closed form. For the case of a bulk medium, properties of fundamental on-site and intersite localized modes are analyzed. On-site and intersite surface localized modes are studied, and we find that they do not exist when nonlocal interactions predominate with respect to local ones.

  6. Tuning dipolar magnetic interactions by controlling individual silica coating of iron oxide nanoparticles

    Science.gov (United States)

    Rivas Rojas, P. C.; Tancredi, P.; Moscoso Londoño, O.; Knobel, M.; Socolovsky, L. M.

    2018-04-01

    Single and fixed size core, core-shell nanoparticles of iron oxides coated with a silica layer of tunable thickness were prepared by chemical routes, aiming to generate a frame of study of magnetic nanoparticles with controlled dipolar interactions. The batch of iron oxides nanoparticles of 4.5 nm radii, were employed as cores for all the coated samples. The latter was obtained via thermal decomposition of organic precursors, resulting on nanoparticles covered with an organic layer that was subsequently used to promote the ligand exchange in the inverse microemulsion process, employed to coat each nanoparticle with silica. The amount of precursor and times of reaction was varied to obtain different silica shell thicknesses, ranging from 0.5 nm to 19 nm. The formation of the desired structures was corroborated by TEM and SAXS measurements, the core single-phase spinel structure was confirmed by XRD, and superparamagnetic features with gradual change related to dipolar interaction effects were obtained by the study of the applied field and temperature dependence of the magnetization. To illustrate that dipolar interactions are consistently controlled, the main magnetic properties are presented and analyzed as a function of center to center minimum distance between the magnetic cores.

  7. Passage-Based Bibliographic Coupling: An Inter-Article Similarity Measure for Biomedical Articles

    Science.gov (United States)

    Liu, Rey-Long

    2015-01-01

    Biomedical literature is an essential source of biomedical evidence. To translate the evidence for biomedicine study, researchers often need to carefully read multiple articles about specific biomedical issues. These articles thus need to be highly related to each other. They should share similar core contents, including research goals, methods, and findings. However, given an article r, it is challenging for search engines to retrieve highly related articles for r. In this paper, we present a technique PBC (Passage-based Bibliographic Coupling) that estimates inter-article similarity by seamlessly integrating bibliographic coupling with the information collected from context passages around important out-link citations (references) in each article. Empirical evaluation shows that PBC can significantly improve the retrieval of those articles that biomedical experts believe to be highly related to specific articles about gene-disease associations. PBC can thus be used to improve search engines in retrieving the highly related articles for any given article r, even when r is cited by very few (or even no) articles. The contribution is essential for those researchers and text mining systems that aim at cross-validating the evidence about specific gene-disease associations. PMID:26440794

  8. Programmed coherent coupling in a synthetic DNA-based excitonic circuit

    Science.gov (United States)

    Boulais, Étienne; Sawaya, Nicolas P. D.; Veneziano, Rémi; Andreoni, Alessio; Banal, James L.; Kondo, Toru; Mandal, Sarthak; Lin, Su; Schlau-Cohen, Gabriela S.; Woodbury, Neal W.; Yan, Hao; Aspuru-Guzik, Alán; Bathe, Mark

    2018-02-01

    Natural light-harvesting systems spatially organize densely packed chromophore aggregates using rigid protein scaffolds to achieve highly efficient, directed energy transfer. Here, we report a synthetic strategy using rigid DNA scaffolds to similarly program the spatial organization of densely packed, discrete clusters of cyanine dye aggregates with tunable absorption spectra and strongly coupled exciton dynamics present in natural light-harvesting systems. We first characterize the range of dye-aggregate sizes that can be templated spatially by A-tracts of B-form DNA while retaining coherent energy transfer. We then use structure-based modelling and quantum dynamics to guide the rational design of higher-order synthetic circuits consisting of multiple discrete dye aggregates within a DX-tile. These programmed circuits exhibit excitonic transport properties with prominent circular dichroism, superradiance, and fast delocalized exciton transfer, consistent with our quantum dynamics predictions. This bottom-up strategy offers a versatile approach to the rational design of strongly coupled excitonic circuits using spatially organized dye aggregates for use in coherent nanoscale energy transport, artificial light-harvesting, and nanophotonics.

  9. The coupling analysis between stock market indices based on permutation measures

    Science.gov (United States)

    Shi, Wenbin; Shang, Pengjian; Xia, Jianan; Yeh, Chien-Hung

    2016-04-01

    Many information-theoretic methods have been proposed for analyzing the coupling dependence between time series. And it is significant to quantify the correlation relationship between financial sequences since the financial market is a complex evolved dynamic system. Recently, we developed a new permutation-based entropy, called cross-permutation entropy (CPE), to detect the coupling structures between two synchronous time series. In this paper, we extend the CPE method to weighted cross-permutation entropy (WCPE), to address some of CPE's limitations, mainly its inability to differentiate between distinct patterns of a certain motif and the sensitivity of patterns close to the noise floor. It shows more stable and reliable results than CPE does when applied it to spiky data and AR(1) processes. Besides, we adapt the CPE method to infer the complexity of short-length time series by freely changing the time delay, and test it with Gaussian random series and random walks. The modified method shows the advantages in reducing deviations of entropy estimation compared with the conventional one. Finally, the weighted cross-permutation entropy of eight important stock indices from the world financial markets is investigated, and some useful and interesting empirical results are obtained.

  10. Analysis on Invulnerability of Wireless Sensor Network towards Cascading Failures Based on Coupled Map Lattice

    Directory of Open Access Journals (Sweden)

    Xiuwen Fu

    2018-01-01

    Full Text Available Previous research of wireless sensor networks (WSNs invulnerability mainly focuses on the static topology, while ignoring the cascading process of the network caused by the dynamic changes of load. Therefore, given the realistic features of WSNs, in this paper we research the invulnerability of WSNs with respect to cascading failures based on the coupled map lattice (CML. The invulnerability and the cascading process of four types of network topologies (i.e., random network, small-world network, homogenous scale-free network, and heterogeneous scale-free network under various attack schemes (i.e., random attack, max-degree attack, and max-status attack are investigated, respectively. The simulation results demonstrate that the rise of interference R and coupling coefficient ε will increase the risks of cascading failures. Cascading threshold values Rc and εc exist, where cascading failures will spread to the entire network when R>Rc or ε>εc. When facing a random attack or max-status attack, the network with higher heterogeneity tends to have a stronger invulnerability towards cascading failures. Conversely, when facing a max-degree attack, the network with higher uniformity tends to have a better performance. Besides that, we have also proved that the spreading speed of cascading failures is inversely proportional to the average path length of the network and the increase of average degree k can improve the network invulnerability.

  11. Bit-level plane image encryption based on coupled map lattice with time-varying delay

    Science.gov (United States)

    Lv, Xiupin; Liao, Xiaofeng; Yang, Bo

    2018-04-01

    Most of the existing image encryption algorithms had two basic properties: confusion and diffusion in a pixel-level plane based on various chaotic systems. Actually, permutation in a pixel-level plane could not change the statistical characteristics of an image, and many of the existing color image encryption schemes utilized the same method to encrypt R, G and B components, which means that the three color components of a color image are processed three times independently. Additionally, dynamical performance of a single chaotic system degrades greatly with finite precisions in computer simulations. In this paper, a novel coupled map lattice with time-varying delay therefore is applied in color images bit-level plane encryption to solve the above issues. Spatiotemporal chaotic system with both much longer period in digitalization and much excellent performances in cryptography is recommended. Time-varying delay embedded in coupled map lattice enhances dynamical behaviors of the system. Bit-level plane image encryption algorithm has greatly reduced the statistical characteristics of an image through the scrambling processing. The R, G and B components cross and mix with one another, which reduces the correlation among the three components. Finally, simulations are carried out and all the experimental results illustrate that the proposed image encryption algorithm is highly secure, and at the same time, also demonstrates superior performance.

  12. Coupling of a single NV center to a fiber-based microcavity

    International Nuclear Information System (INIS)

    Christoph Becher

    2014-01-01

    The read-out of the spin state of a NV center in diamond or the transfer of quantum information between its spin and a photon would profit enormously from coupling the NV center's optical transitions to a microcavity with a highly directional output. We here report on such a coupling of a single NV center in a nanodiamond to a fiber-based, tunable microcavity at room temperature. Making use of the NV center's strongly broadened emission we operate in the regime of phonon-assisted cavity seeding and realize a widely tunable, narrow-band single photon source. A master equation model well reproduces our experimental results and predicts a transition into a Purcell-enhanced emission regime at low temperatures where up to 65% of the NV emission would be channeled into the cavity mode for our given experimental parameters. Further reducing scattering losses from the nanodiamonds could enable schemes for cavity-enhanced spin measurements or creation of entangled states. (author)

  13. Passage-Based Bibliographic Coupling: An Inter-Article Similarity Measure for Biomedical Articles.

    Directory of Open Access Journals (Sweden)

    Rey-Long Liu

    Full Text Available Biomedical literature is an essential source of biomedical evidence. To translate the evidence for biomedicine study, researchers often need to carefully read multiple articles about specific biomedical issues. These articles thus need to be highly related to each other. They should share similar core contents, including research goals, methods, and findings. However, given an article r, it is challenging for search engines to retrieve highly related articles for r. In this paper, we present a technique PBC (Passage-based Bibliographic Coupling that estimates inter-article similarity by seamlessly integrating bibliographic coupling with the information collected from context passages around important out-link citations (references in each article. Empirical evaluation shows that PBC can significantly improve the retrieval of those articles that biomedical experts believe to be highly related to specific articles about gene-disease associations. PBC can thus be used to improve search engines in retrieving the highly related articles for any given article r, even when r is cited by very few (or even no articles. The contribution is essential for those researchers and text mining systems that aim at cross-validating the evidence about specific gene-disease associations.

  14. Couples-based interventions following prostate cancer treatment: a narrative review

    Science.gov (United States)

    Emanu, Jessica C.; Avildsen, Isabelle

    2015-01-01

    Background Sexual dysfunction following prostate cancer (PC) treatment often results in sexual avoidance and a loss of sexual intimacy, which can lead to relationship distress. This review aims to evaluate six studies intended to address relational and sexual intimacy following PC treatment and discuss methodological concerns which may help produce more effective interventions. Methods Electronic databases used to conduct literature searches included Medline, PsychINFO, and Web of Science. Studies were included if they were: randomized controlled trials (RCTs) using samples of men diagnosed with PC of any stage, had a psychosocial intervention, and addressed at least one sexual and relational outcome. Results As a whole, the literature has produced mixed results. While significant findings were reported, many of the primary hypotheses were not achieved. The six studies show that men with PC may benefit from education and support related to treatment options for erectile dysfunction (ED), whereas their partners may benefit more from interventions focused on relational issues. Important methodological limitations included: selection of general outcome measures as opposed to measures specific to sexuality or intimacy outcomes, lack of assessing distress or bother of the patient/couples as study entry criteria, heterogeneity of study populations, and lack of innovative intervention content as the current studies tested standard educational interventions, sex therapies techniques, and couples therapy strategies with only marginal success. Conclusions Interventions based on innovative theoretical approaches as well as study designs that address the outlined methodological limitations are needed in this area. PMID:26813683

  15. Finite Element Analysis of Mechanical Characteristics of Dropped Eggs Based on Fluid-Solid Coupling Theory

    Directory of Open Access Journals (Sweden)

    Song Haiyan

    2017-01-01

    Full Text Available It is important to study the properties and mechanics of egg drop impacts in order to reduce egg loss during processing and logistics and to provide a basis for the protective packaging of egg products. In this paper, we present the results of our study of the effects of the structural parameters on the mechanical properties of an egg using a finite element model of the egg. Based on Fluid-Solid coupling theory, a finite element model of an egg was constructed using ADINA, a finite element calculation and analysis software package. To simplify the model, the internal fluid of the egg was considered to be a homogeneous substance. The egg drop impact was simulated by the coupling solution, and the feasibility of the model was verified by comparison with the experimental results of a drop test. In summary, the modeling scheme was shown to be feasible and the simulation results provide a theoretical basis for the optimum design of egg packaging and egg processing equipment.

  16. Synchronization of linearly coupled unified chaotic systems based on linear balanced feedback scheme with constraints

    International Nuclear Information System (INIS)

    Chen, H.-H.; Chen, C.-S.; Lee, C.-I

    2009-01-01

    This paper investigates the synchronization of unidirectional and bidirectional coupled unified chaotic systems. A balanced coupling coefficient control method is presented for global asymptotic synchronization using the Lyapunov stability theorem and a minimum scheme with no constraints/constraints. By using the result of the above analysis, the balanced coupling coefficients are then designed to achieve the chaos synchronization of linearly coupled unified chaotic systems. The feasibility and effectiveness of the proposed chaos synchronization scheme are verified via numerical simulations.

  17. Covalent Coupling of Nanoparticles with Low-Density Functional Ligands to Surfaces via Click Chemistry

    NARCIS (Netherlands)

    Rianasari, I.; de Jong, Machiel Pieter; Huskens, Jurriaan; van der Wiel, Wilfred Gerard

    2013-01-01

    We demonstrate the application of the 1,3-dipolar cycloaddition (“click‿ reaction) to couple gold nanoparticles (Au NPs) functionalized with low densities of functional ligands. The ligand coverage on the citrate-stabilized Au NPs was adjusted by the ligand:Au surface atom ratio, while maintaining

  18. Anisotropic semivortices in dipolar spinor condensates controlled by Zeeman splitting

    Science.gov (United States)

    Liao, Bingjin; Li, Shoubo; Huang, Chunqing; Luo, Zhihuan; Pang, Wei; Tan, Haishu; Malomed, Boris A.; Li, Yongyao

    2017-10-01

    Spatially anisotropic solitary vortices, i.e., bright anisotropic vortex solitons (AVSs), supported by anisotropic dipole-dipole interactions, were recently predicted in spin-orbit-coupled binary Bose-Einstein condensates (BECs), in the form of two-dimensional semivortices (complexes built of zero-vorticity and vortical components). We demonstrate that the shape of the AVSs—horizontal or vertical, with respect to the in-plane polarization of the atomic dipole moments in the underlying BEC—may be effectively controlled by the strength Ω of the Zeeman splitting (ZS). A transition from the horizontal to vertical shape with the increase of Ω is found numerically and explained analytically. At the transition point, the AVS assumes the shape of an elliptical ring. The mobility of horizontal AVSs is studied, too, with the conclusion that, with the increase of Ω , their negative effective mass changes the sign to positive via a point at which the effective mass diverges. Lastly, we report a new species of inverted AVSs, with the zero-vorticity and vortex component placed in lower- and higher-energy components, as defined by the ZS. They are excited states, with respect to the ground states provided by the usual AVSs. Quite surprisingly, inverted AVSs are stable in a large parameter region.

  19. Adjoint-Based a Posteriori Error Estimation for Coupled Time-Dependent Systems

    KAUST Repository

    Asner, Liya; Tavener, Simon; Kay, David

    2012-01-01

    We consider time-dependent parabolic problem s coupled across a common interface which we formulate using a Lagrange multiplier construction and solve by applying a monolithic solution technique. We derive an adjoint-based a posteriori error representation for a quantity of interest given by a linear functional of the solution. We establish the accuracy of our error representation formula through numerical experimentation and investigate the effect of error in the adjoint solution. Crucially, the error representation affords a distinction between temporal and spatial errors and can be used as a basis for a blockwise time-space refinement strategy. Numerical tests illustrate the efficacy of the refinement strategy by capturing the distinctive behavior of a localized traveling wave solution. The saddle point systems considered here are equivalent to those arising in the mortar finite element technique for parabolic problems. © 2012 Society for Industrial and Applied Mathematics.

  20. Origin of Starting Earthquakes under Complete Coupling of the Lithosphere Plates and a Base

    Science.gov (United States)

    Babeshko, V. A.; Evdokimova, O. V.; Babeshko, O. M.; Zaretskaya, M. V.; Gorshkova, E. M.; Mukhin, A. S.; Gladskoi, I. B.

    2018-02-01

    The boundary problem of rigid coupling of lithospheric plates modeled by Kirchhoff plates with a base represented by a three-dimensional deformable layered medium is considered. The possibility of occurrence of a starting earthquake in such a block structure is investigated. For this purpose, two states of this medium in the static mode are considered. In the first case, the semi-infinite lithospheric plates in the form of half-planes are at a distance so that the distance between the end faces is different from zero. In the second case, the lithospheric plates come together to zero spacing between them. Calculations have shown that in this case more complex movements of the Earth's surface are possible. Among such movements are the cases described in our previous publications [1, 2].

  1. On diversity performance of two-element coupling element based antenna structure for mobile terminal

    DEFF Research Database (Denmark)

    Al-Hadi, Azremi Abdullah; Toivanen, Juha; Laitinen, Tommi

    2010-01-01

    .1 and the diversity gain is equal to 10.2 dB at 99% reliability level using selection combining technique across simulation and both measurement methods. The measurement techniques are compared to show how accurately the diversity performance of a mobile terminal antenna can be estimated.......In wireless communication systems, multipath interference has a significant impact on system design and performance. Fast fading is caused by the coherent summation of one or more echoes from many reflection points reaching the receive antenna. Antenna diversity can be used to mitigate multipath...... fading. The main challenge of antenna diversity in practical application is the integration of multiple antennas on a small ground plane. Two-element antenna structure based on coupling element antenna concept for diversity application has been studied in previous work and it has shown to be feasible...

  2. PRESBYOPIA OPTOMETRY METHOD BASED ON DIOPTER REGULATION AND CHARGE COUPLE DEVICE IMAGING TECHNOLOGY.

    Science.gov (United States)

    Zhao, Q; Wu, X X; Zhou, J; Wang, X; Liu, R F; Gao, J

    2015-01-01

    With the development of photoelectric technology and single-chip microcomputer technology, objective optometry, also known as automatic optometry, is becoming precise. This paper proposed a presbyopia optometry method based on diopter regulation and Charge Couple Device (CCD) imaging technology and, in the meantime, designed a light path that could measure the system. This method projects a test figure to the eye ground and then the reflected image from the eye ground is detected by CCD. The image is then automatically identified by computer and the far point and near point diopters are determined to calculate lens parameter. This is a fully automatic objective optometry method which eliminates subjective factors of the tested subject. Furthermore, it can acquire the lens parameter of presbyopia accurately and quickly and can be used to measure the lens parameter of hyperopia, myopia and astigmatism.

  3. Energy-based fatigue model for shape memory alloys including thermomechanical coupling

    Science.gov (United States)

    Zhang, Yahui; Zhu, Jihong; Moumni, Ziad; Van Herpen, Alain; Zhang, Weihong

    2016-03-01

    This paper is aimed at developing a low cycle fatigue criterion for pseudoelastic shape memory alloys to take into account thermomechanical coupling. To this end, fatigue tests are carried out at different loading rates under strain control at room temperature using NiTi wires. Temperature distribution on the specimen is measured using a high speed thermal camera. Specimens are tested to failure and fatigue lifetimes of specimens are measured. Test results show that the fatigue lifetime is greatly influenced by the loading rate: as the strain rate increases, the fatigue lifetime decreases. Furthermore, it is shown that the fatigue cracks initiate when the stored energy inside the material reaches a critical value. An energy-based fatigue criterion is thus proposed as a function of the irreversible hysteresis energy of the stabilized cycle and the loading rate. Fatigue life is calculated using the proposed model. The experimental and computational results compare well.

  4. Energy-based fatigue model for shape memory alloys including thermomechanical coupling

    International Nuclear Information System (INIS)

    Zhang, Yahui; Zhu, Jihong; Moumni, Ziad; Zhang, Weihong; Van Herpen, Alain

    2016-01-01

    This paper is aimed at developing a low cycle fatigue criterion for pseudoelastic shape memory alloys to take into account thermomechanical coupling. To this end, fatigue tests are carried out at different loading rates under strain control at room temperature using NiTi wires. Temperature distribution on the specimen is measured using a high speed thermal camera. Specimens are tested to failure and fatigue lifetimes of specimens are measured. Test results show that the fatigue lifetime is greatly influenced by the loading rate: as the strain rate increases, the fatigue lifetime decreases. Furthermore, it is shown that the fatigue cracks initiate when the stored energy inside the material reaches a critical value. An energy-based fatigue criterion is thus proposed as a function of the irreversible hysteresis energy of the stabilized cycle and the loading rate. Fatigue life is calculated using the proposed model. The experimental and computational results compare well. (paper)

  5. Plasmonic metalens based on coupled resonators for focusing of surface plasmons

    KAUST Repository

    Xu, Quan

    2016-11-29

    As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles. More specifically, we show how to control the interaction between the constituent EIT resonators to efficiently manipulate the focusing intensity of SPs. We also demonstrated that the proposed metalens is capable of achieving frequency division multiplexing. The power and simplicity of the proposed design would offer promising opportunities for practical plasmonic devices.

  6. Impedance Based Characterization of a High-Coupled Screen Printed PZT Thick Film Unimorph Energy Harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, R.; Borregaard, L. M.

    2014-01-01

    The single degree of freedom mass-spring-damper system is the most common approach for deriving a full electromechanical model for the piezoelectric vibration energy harvester. In this paper, we revisit this standard electromechanical model by focusing on the impedance of the piezoelectric device...... parameters which, by means of the piezoelectric impedance expression, all can be determined accurately by electrical measurements. It is shown how four of five lumped parameters can be determined from a single impedance measurement scan, considerably reducing the characterization effort. The remaining...... parameter is determined from shaker measurements, and a highly accurate agreement is found between model and measurements on a unimorph MEMS-based screen printed PZT harvester. With a high coupling term K-2 Q similar or equal to 7, the harvester exhibits two optimum load points. The peak power performance...

  7. Asymmetric light transmission based on coupling between photonic crystal waveguides and L1/L3 cavity

    Science.gov (United States)

    Zhang, Jinqiannan; Chai, Hongyu; Yu, Zhongyuan; Cheng, Xiang; Ye, Han; Liu, Yumin

    2017-09-01

    A compact design of all-optical diode with mode conversion function based on a two-dimensional photonic crystal waveguide and an L1 or L3 cavity is theoretically investigated. The proposed photonic crystal structures comprise a triangular arrangement of air holes embedded in a silicon substrate. Asymmetric light propagation is achieved via the spatial mode match/mismatch in the coupling region. The simulations show that at each cavity's resonance frequency, the transmission efficiency of the structure with the L1 and L3 cavities reach 79% and 73%, while the corresponding unidirectionalities are 46 and 37 dB, respectively. The functional frequency can be controlled by simply adjusting the radii of specific air holes in the L1 and L3 cavities. The proposed structure can be used as a frequency filter, a beam splitter and has potential applications in all-optical integrated circuits.

  8. Performance of human body communication-based wearable ECG with capacitive coupling electrodes.

    Science.gov (United States)

    Sakuma, Jun; Anzai, Daisuke; Wang, Jianqing

    2016-09-01

    Wearable electrocardiogram (ECG) is attracting much attention in daily healthcare applications, and human body communication (HBC) technology provides an evident advantage in making the sensing electrodes of ECG also working for transmission through the human body. In view of actual usage in daily life, however, non-contact electrodes to the human body are desirable. In this Letter, the authors discussed the ECG circuit structure in the HBC-based wearable ECG for removing the common mode noise when employing non-contact capacitive coupling electrodes. Through the comparison of experimental results, they have shown that the authors' proposed circuit structure with the third electrode directly connected to signal ground can provide an effect on common mode noise reduction similar to the usual drive-right-leg circuit, and a sufficiently good acquisition performance of ECG signals.

  9. A new crystal structure fragment-based pharmacophore method for G protein-coupled receptors

    DEFF Research Database (Denmark)

    Fidom, Kimberley; Isberg, Vignir; Hauser, Alexander Sebastian

    2015-01-01

    and receptor residue pairs, from crystal structure complexes. We describe the procedure to collect a library with more than 250 fragments covering 29 residue positions within the generic transmembrane binding pocket. We describe how the library fragments are recombined and inferred to build pharmacophores...... for new targets. A validating retrospective virtual screening of histamine H1 and H3 receptor pharmacophores yielded area-under-the-curves of 0.88 and 0.82, respectively. The fragment-based method has the unique advantage that it can be applied to targets for which no (homologous) crystal structures...... or ligands are known. 47% of the class A G protein-coupled receptors can be targeted with at least four-element pharmacophores. The fragment libraries can also be used to grow known ligands or for rotamer refinement of homology models. Researchers can download the complete fragment library or a subset...

  10. Protein A Detection Based on Quantum Dots-Antibody Bioprobe Using Fluorescence Coupled Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Lin Qiu

    2014-01-01

    Full Text Available In this report, fluorescence detection coupled capillary electrophoresis (CE-FL was used to detect Protein A. Antibody was first labeled with Cy5 and then mixed with quantum dots (QDs to form QDs-antibody bioprobe. Further, we observed fluorescence resonance energy transfer (FRET from QDs donor to Cy5 acceptor. The bioprobe was formed and brought QDs and Cy5 close enough to allow FRET to occur. After adding protein A, the FRET system was broken and caused the FRET signal to decrease. Thus, a new method for the determination of protein A was proposed based on the FRET signal changes. This study provides a new trail of thought for the detection of protein.

  11. Quantum Key Distribution Based on a Weak-Coupling Cavity QED Regime

    International Nuclear Information System (INIS)

    Li Chun-Yan; Li Yan-Song

    2011-01-01

    We present a quantum key distribution scheme using a weak-coupling cavity QED regime based on quantum dense coding. Hybrid entanglement states of photons and electrons are used to distribute information. We just need to transmit photons without storing them in the scheme. The electron confined in a quantum dot, which is embedded in a microcavity, is held by one of the legitimate users throughout the whole communication process. Only the polarization of a single photon and spin of electron measurements are applied in this protocol, which are easier to perform than collective-Bell state measurements. Linear optical apparatus, such as a special polarizing beam splitter in a circular basis and single photon operations, make it more flexible to realize under current technology. Its efficiency will approach 100% in the ideal case. The security of the scheme is also discussed. (general)

  12. Coupling of CORINAIR Data to Cost-effective Emission Reduction Strategies Based on Critical Thresholds

    International Nuclear Information System (INIS)

    Johansson, M.; Guardans, R.; Lindstrom, M.

    1999-12-01

    This report summarizes the results of a workshop held by the participants in the EU/LIFE project: Coupling of CORINAIR data to cost-effective emission reduction strategies based on critical thresholds. The project participants include FEI, Filand, NERI, Denmark, CIEMAT, Spain, Lund Univ. Sweden. EMEP/MSC-W, UN/ECE/WGE/CCE and IIASA. The main objective of the project is to support national activities in assessing the spatial and temporal details of emissions of sulphur, nitrogen oxides, ammonium and volatile organic compounds and the impacts of acidification, eutrophication and ground level ozone. The reproject workshop enabled participants to report preliminary results of the two main tasks, emissions and impacts and to agree on common solutions for the final results. (Author) 11 refs

  13. All-optical bistable logic control based on coupled Tamm plasmons.

    Science.gov (United States)

    Zhang, Wei Li; Jiang, Yao; Zhu, Ye Yu; Wang, Fen; Rao, Yun Jiang

    2013-10-15

    A method for realizing low-threshold all-optical bistable logic control is proposed based on Tamm plasmons (TPs), which are formed in an asymmetric dielectric Bragg reflector (DBR)-metal-DBR (ADMD) structure with a layer of Kerr medium embedded. The ADMD structure supports two TPs due to coupling of trapped modes at each metal-DBR interface, generating two dips in the structure's reflection spectrum. Thus, control (i.e., pump) and controlled (i.e., probe) light with wavelengths close to the two dips, respectively, can be imported. It is verified theoretically that, thanks to the enhanced Kerr nonlinearity related to excitation of high-quality TP, bistable switching at very low injection intensity can be initiated by strength or direction variation of the pump. Meanwhile, the probe changes correspondingly with the pump. Thus, all-optical bistable logic operation of the probe can be controlled by the pump.

  14. Compact four-channel terahertz demultiplexer based on directional coupling photonic crystal

    Science.gov (United States)

    Jiu-Sheng, Li; Han, Liu; Le, Zhang

    2015-09-01

    Electromagnetic polarization conveys valuable information for signal processing. Manipulation of terahertz wavelength demultiplexer exhibits tremendous potential in developing application of terahertz science and technology. We propose an approach to separate efficiently four frequencies terahertz waves based on three cascaded directional coupling two-dimensional photonic crystal waveguides. Both plane wave expansion method and finite-difference time-domain method are used to calculate and analyze the characteristics of the proposed device. The simulation results show that the designed terahertz wavelength demultiplexer can split four different wavelengths of terahertz wave into different propagation directions with high transmittance and low crosstalk. The present device is very compact and the total size is 6.8×10.6 mm2. This enables the terahertz wavelength demultiplexer to be used in terahertz wave system and terahertz wave integrated circuit fields.

  15. Optimal control of transverse mode coupling instability based on the two particle model

    International Nuclear Information System (INIS)

    Ogata, Atsushi

    1985-01-01

    The optimal regulator design technique is applied to asymptotically stabilize the transverse mode coupling instability of a storage ring. The state equations are based on the two particle model. These are a pair of equation sets, one for the first and one for the second half of the synchrotron phase. Each set consists of first-order difference equations in vector-matrix form, with time step equal to the revolution time of the ring. Solution of the discrete Riccati equation gives the optimal gain matrix of the transverse feedback. Computer simulations are carried out to verify its effectiveness. Some modifications necessary to apply it to the real accelerator operation are made. The old methods, the classical output feedback and the reactive feedback, are interpreted from the viewpoint of the optimal control. (orig.)

  16. Study of the origin of magnetic couples induced by spin-orbit coupling in Co/Pt-based asymmetrical structures

    International Nuclear Information System (INIS)

    Drouard, Marc

    2014-01-01

    In order to reduce power consumption in next generations' electronic devices, one potential solution is to implement non-volatility in memory cells. In this goal, the magnetization switching of a ferromagnetic material has been used in a memory concept: the MRAM. The latest development of this technology, called SOT-RAM, is based on new phenomena called SOTs (Spin-Orbit Torques) in order to control magnetization direction. Contrary to precedent generations (STT-MRAM), it should achieve a higher operating speed and an endurance adapted for cache and main memories applications. SOTs is a generic term referring to all the effects, linked to the spin-orbit interaction, and that enable magnetization reversal. They are yet not perfectly understood. The main objective of this Ph.D. was then to study these SOTs through a quasi-static experimental measurement setup based on anomalous and planar Hall effects. Its implementation and the associated analysis method, as well as the required theoretical considerations for data interpretation are detailed in this manuscript. It has been highlighted that magnetization switching in perpendicularly magnetization cobalt-platinum Systems cannot be explained by the simple models considered thus far in the literature. As a matter of fact it has been evidenced that at least two effects have to be considered in order to explain observed phenomena. In addition, they present different susceptibility both to a modification of the crystal structure and to a temperature change. (author) [fr

  17. Spin Diffusion and Spin Lattice Relaxation of Dipolar Order in Solids Containing Paramagnetic Impurities

    International Nuclear Information System (INIS)

    Furman, G.B.; Panich, A.M.; Goren, S.D.

    1998-01-01

    The phenomena of spin diffusion and spin lattice relaxation of nuclear dipolar order in solids containing paramagnetic impurities (PI) is considered. We show that at the beginning of the relaxation process the diffusion vanishing regime realizes with non-exponential time dependence, R(t) ∼ exp [- (t/T 1d ) α ], where T 1d ∼ C p -1/α , C p is PI's concentration. For a homogeneous distribution of Pis and nuclear spins, α=Q/6, where Q is the sample dimensionality; for an inhomogeneous distribution, the sample is divided into q-dimensional subsystems, each containing one PI, yield- ing α= (Q + q) /6. This result coincides with experimental data for CaF 2 doped with 0.8 - 10 -3 ωt % of Mn 2+ , where the non-exponential decay of the dipolar signal with α= 0.83 has been observed [3]. Fitting the experimental data yields a good agreement with T 1d = 66 ms . For another independent check of the obtained results we use dependence of the relaxation time on impurities concentration. In accordance that 1/α=1.2 , we have T 1d ∼ C p -1 '. 2 . Exactly this dependence on impurity concentration of the relaxation time has been found in the experiment. Then the relaxation regime starts as a non-exponential time dependent, proceed asymptotically to an to an exponential function of time, to so called diffusion limited relaxation regime with relaxation time T 1d D is inversely depends on impurities concentration. This kind of relaxation behavior of the dipolar order takes place in the experiment [2]. Using experimental results [2] from this two regime we can estimate the diffusion coefficient of the nuclear dipolar order in CaF 2 , which gives for typical values of impurity concentration C p ∼ 10 18 cm 3 the diffusion coefficient of dipolar order in the interval D ∼ 10 -11 -i- 10 -12 cm 2 /sec which is coincide to the case of Zeeman energy spin diffusion

  18. Rock Failure Analysis Based on a Coupled Elastoplastic-Logarithmic Damage Model

    Science.gov (United States)

    Abdia, M.; Molladavoodi, H.; Salarirad, H.

    2017-12-01

    The rock materials surrounding the underground excavations typically demonstrate nonlinear mechanical response and irreversible behavior in particular under high in-situ stress states. The dominant causes of irreversible behavior are plastic flow and damage process. The plastic flow is controlled by the presence of local shear stresses which cause the frictional sliding. During this process, the net number of bonds remains unchanged practically. The overall macroscopic consequence of plastic flow is that the elastic properties (e.g. the stiffness of the material) are insensitive to this type of irreversible change. The main cause of irreversible changes in quasi-brittle materials such as rock is the damage process occurring within the material. From a microscopic viewpoint, damage initiates with the nucleation and growth of microcracks. When the microcracks length reaches a critical value, the coalescence of them occurs and finally, the localized meso-cracks appear. The macroscopic and phenomenological consequence of damage process is stiffness degradation, dilatation and softening response. In this paper, a coupled elastoplastic-logarithmic damage model was used to simulate the irreversible deformations and stiffness degradation of rock materials under loading. In this model, damage evolution & plastic flow rules were formulated in the framework of irreversible thermodynamics principles. To take into account the stiffness degradation and softening on post-peak region, logarithmic damage variable was implemented. Also, a plastic model with Drucker-Prager yield function was used to model plastic strains. Then, an algorithm was proposed to calculate the numerical steps based on the proposed coupled plastic and damage constitutive model. The developed model has been programmed in VC++ environment. Then, it was used as a separate and new constitutive model in DEM code (UDEC). Finally, the experimental Oolitic limestone rock behavior was simulated based on the developed

  19. Precise single-qubit control of the reflection phase of a photon mediated by a strongly-coupled ancilla–cavity system

    Science.gov (United States)

    Motzoi, F.; Mølmer, K.

    2018-05-01

    We propose to use the interaction between a single qubit atom and a surrounding ensemble of three level atoms to control the phase of light reflected by an optical cavity. Our scheme employs an ensemble dark resonance that is perturbed by the qubit atom to yield a single-atom single photon gate. We show here that off-resonant excitation towards Rydberg states with strong dipolar interactions offers experimentally-viable regimes of operations with low errors (in the 10‑3 range) as required for fault-tolerant optical-photon, gate-based quantum computation. We also propose and analyze an implementation within microwave circuit-QED, where a strongly-coupled ancilla superconducting qubit can be used in the place of the atomic ensemble to provide high-fidelity coupling to microwave photons.

  20. Development of CO2 inversion system based on the adjoint of the global coupled transport model

    Science.gov (United States)

    Belikov, Dmitry; Maksyutov, Shamil; Chevallier, Frederic; Kaminski, Thomas; Ganshin, Alexander; Blessing, Simon

    2014-05-01

    We present the development of an inverse modeling system employing an adjoint of the global coupled transport model consisting of the National Institute for Environmental Studies (NIES) Eulerian transport model (TM) and the Lagrangian plume diffusion model (LPDM) FLEXPART. NIES TM is a three-dimensional atmospheric transport model, which solves the continuity equation for a number of atmospheric tracers on a grid spanning the entire globe. Spatial discretization is based on a reduced latitude-longitude grid and a hybrid sigma-isentropic coordinate in the vertical. NIES TM uses a horizontal resolution of 2.5°×2.5°. However, to resolve synoptic-scale tracer distributions and to have the ability to optimize fluxes at resolutions of 0.5° and higher we coupled NIES TM with the Lagrangian model FLEXPART. The Lagrangian component of the forward and adjoint models uses precalculated responses of the observed concentration to the surface fluxes and 3-D concentrations field simulated with the FLEXPART model. NIES TM and FLEXPART are driven by JRA-25/JCDAS reanalysis dataset. Construction of the adjoint of the Lagrangian part is less complicated, as LPDMs calculate the sensitivity of measurements to the surrounding emissions field by tracking a large number of "particles" backwards in time. Developing of the adjoint to Eulerian part was performed with automatic differentiation tool the Transformation of Algorithms in Fortran (TAF) software (http://www.FastOpt.com). This method leads to the discrete adjoint of NIES TM. The main advantage of the discrete adjoint is that the resulting gradients of the numerical cost function are exact, even for nonlinear algorithms. The overall advantages of our method are that: 1. No code modification of Lagrangian model is required, making it applicable to combination of global NIES TM and any Lagrangian model; 2. Once run, the Lagrangian output can be applied to any chemically neutral gas; 3. High-resolution results can be obtained over

  1. Corrosion behaviour and galvanic coupling with steel of Al-based coating alternatives to electroplated cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fasuba, O.A.; Yerokhin, A., E-mail: A.Yerokhin@sheffield.ac.uk; Matthews, A.; Leyland, A.

    2013-08-15

    The galvanic corrosion behaviour of bare steel coupled to steel with an Al–Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al–Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV. - Highlights: • Al-based slurry coating has best galvanic compatibility with steel. • Mg, Cr, P in Al-based slurry coating reinforce its corrosion resistance. • Ennoblement of Al–Zn flake coating compromises its cathodic protection. • Poor corrosion behaviour of arc sprayed Al coating caused by rough morphology. • Electrochemical noise provides adequate estimates of galvanic behaviour.

  2. Light controlled spin properties and radiative coupling of CdSe based quantum dots

    International Nuclear Information System (INIS)

    Schmidt, T.; Worschech, L.; Scheibner, M.; Forchel, A.; Slobodskyy, T.; Schmidt, G.; Molenkamp, L.W.; Passow, T.; Hommel, D.

    2007-01-01

    The authors have studied the photoluminescence of large and small ensembles of CdSe based quantum dots (QDs) in magnetic fields for different polarizations and powers of the exciting laser light. By means of polarization spectroscopy the g factors and spin lifetimes were determined for semimagnetic CdMnSe QDs with nominal Mn contents of 0%, 1% and 2%. Also the corresponding exciton lifetimes were analyzed. A sign reversal of the QD exciton g factor was identified comparing the polarization of QD luminescence with 0% and 2% Mn. For small excitation powers QDs with 1% Mn have a vanishing small value of g. Interestingly, by ramping up the excitation power of the exciting laser the exciton g factor increases by up to a factor of 30. Different heating mechanism were identified by characteristic power dependencies. For low excitation powers indirect heating of the spin systems occurs whereas above a critical power direct heating due to photoexcited carriers dominates. It is also demonstrated that in CdMnSe QDs the circular polarization of the luminescence can be inverted solely controlled by the laser power. Applying mesa techniques, collective radiance of QDs is demonstrated. For that purpose the radiative lifetimes of QDs with such a density that there are many dots within an area proportional to the square of the optical wavelength were studied for different numbers of QDs removed from that area. A comparison of photoluminescence decay times obtained for non-resonant and quasi-resonant excitation conditions and different mesa sizes is given. Radiative coupling of QDs takes place at least on the order of 150 nm. This length is comparable to the dimensions of lithographically well definable nanostructures and may therefore provide a mechanism to couple discrete quantum objects on a large scale. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. CORBA and MPI-based 'backbone' for coupling advanced simulation tools

    International Nuclear Information System (INIS)

    Seydaliev, M.; Caswell, D.

    2014-01-01

    There is a growing international interest in using coupled, multidisciplinary computer simulations for a variety of purposes, including nuclear reactor safety analysis. Reactor behaviour can be modeled using a suite of computer programs simulating phenomena or predicting parameters that can be categorized into disciplines such as Thermalhydraulics, Neutronics, Fuel, Fuel Channels, Fission Product Release and Transport, Containment and Atmospheric Dispersion, and Severe Accident Analysis. Traditionally, simulations used for safety analysis individually addressed only the behaviour within a single discipline, based upon static input data from other simulation programs. The limitation of using a suite of stand-alone simulations is that phenomenological interdependencies or temporal feedback between the parameters calculated within individual simulations cannot be adequately captured. To remove this shortcoming, multiple computer simulations for different disciplines must exchange data during runtime to address these interdependencies. This article describes the concept of a new framework, which we refer to as the 'Backbone', to provide the necessary runtime exchange of data. The Backbone, currently under development at AECL for a preliminary feasibility study, is a hybrid design using features taken from the Common Object Request Broker Architecture (CORBA), a standard defined by the Object Management Group, and the Message Passing Interface (MPI), a standard developed by a group of researchers from academia and industry. Both have well-tested and efficient implementations, including some that are freely available under the GNU public licenses. The CORBA component enables individual programs written in different languages and running on different platforms within a network to exchange data with each other, thus behaving like a single application. MPI provides the process-to-process intercommunication between these programs. This paper outlines the different CORBA and

  4. Floquet-Magnus expansion for general N-coupled spins systems in magic-angle spinning nuclear magnetic resonance spectra

    Science.gov (United States)

    Mananga, Eugene Stephane; Charpentier, Thibault

    2015-04-01

    In this paper we present a theoretical perturbative approach for describing the NMR spectrum of strongly dipolar-coupled spin systems under fast magic-angle spinning. Our treatment is based on two approaches: the Floquet approach and the Floquet-Magnus expansion. The Floquet approach is well known in the NMR community as a perturbative approach to get analytical approximations. Numerical procedures are based on step-by-step numerical integration of the corresponding differential equations. The Floquet-Magnus expansion is a perturbative approach of the Floquet theory. Furthermore, we address the " γ -encoding" effect using the Floquet-Magnus expansion approach. We show that the average over " γ " angle can be performed for any Hamiltonian with γ symmetry.

  5. Quantifying human behavior uncertainties in a coupled agent-based model for water resources management

    Science.gov (United States)

    Hyun, J. Y.; Yang, Y. C. E.; Tidwell, V. C.; Macknick, J.

    2017-12-01

    Modeling human behaviors and decisions in water resources management is a challenging issue due to its complexity and uncertain characteristics that affected by both internal (such as stakeholder's beliefs on any external information) and external factors (such as future policies and weather/climate forecast). Stakeholders' decision regarding how much water they need is usually not entirely rational in the real-world cases, so it is not quite suitable to model their decisions with a centralized (top-down) approach that assume everyone in a watershed follow the same order or pursue the same objective. Agent-based modeling (ABM) uses a decentralized approach (bottom-up) that allow each stakeholder to make his/her own decision based on his/her own objective and the belief of information acquired. In this study, we develop an ABM which incorporates the psychological human decision process by the theory of risk perception. The theory of risk perception quantifies human behaviors and decisions uncertainties using two sequential methodologies: the Bayesian Inference and the Cost-Loss Problem. The developed ABM is coupled with a regulation-based water system model: Riverware (RW) to evaluate different human decision uncertainties in water resources management. The San Juan River Basin in New Mexico (Figure 1) is chosen as a case study area, while we define 19 major irrigation districts as water use agents and their primary decision is to decide the irrigated area on an annual basis. This decision will be affected by three external factors: 1) upstream precipitation forecast (potential amount of water availability), 2) violation of the downstream minimum flow (required to support ecosystems), and 3) enforcement of a shortage sharing plan (a policy that is currently undertaken in the region for drought years). Three beliefs (as internal factors) that correspond to these three external factors will also be considered in the modeling framework. The objective of this study is

  6. [A capillary blood flow velocity detection system based on linear array charge-coupled devices].

    Science.gov (United States)

    Zhou, Houming; Wang, Ruofeng; Dang, Qi; Yang, Li; Wang, Xiang

    2017-12-01

    In order to detect the flow characteristics of blood samples in the capillary, this paper introduces a blood flow velocity measurement system based on field-programmable gate array (FPGA), linear charge-coupled devices (CCD) and personal computer (PC) software structure. Based on the analysis of the TCD1703C and AD9826 device data sheets, Verilog HDL hardware description language was used to design and simulate the driver. Image signal acquisition and the extraction of the real-time edge information of the blood sample were carried out synchronously in the FPGA. Then a series of discrete displacement were performed in a differential operation to scan each of the blood samples displacement, so that the sample flow rate could be obtained. Finally, the feasibility of the blood flow velocity detection system was verified by simulation and debugging. After drawing the flow velocity curve and analyzing the velocity characteristics, the significance of measuring blood flow velocity is analyzed. The results show that the measurement of the system is less time-consuming and less complex than other flow rate monitoring schemes.

  7. Non-contact evaluation of milk-based products using air-coupled ultrasound

    Science.gov (United States)

    Meyer, S.; Hindle, S. A.; Sandoz, J.-P.; Gan, T. H.; Hutchins, D. A.

    2006-07-01

    An air-coupled ultrasonic technique has been developed and used to detect physicochemical changes of liquid beverages within a glass container. This made use of two wide-bandwidth capacitive transducers, combined with pulse-compression techniques. The use of a glass container to house samples enabled visual inspection, helping to verify the results of some of the ultrasonic measurements. The non-contact pulse-compression system was used to evaluate agglomeration processes in milk-based products. It is shown that the amplitude of the signal varied with time after the samples had been treated with lactic acid, thus promoting sample destabilization. Non-contact imaging was also performed to follow destabilization of samples by scanning in various directions across the container. The obtained ultrasonic images were also compared to those from a digital camera. Coagulation with glucono-delta-lactone of skim milk poured into this container could be monitored within a precision of a pH of 0.15. This rapid, non-contact and non-destructive technique has shown itself to be a feasible method for investigating the quality of milk-based beverages, and possibly other food products.

  8. Coupling Agent-Based and Groundwater Modeling to Explore Demand Management Strategies for Shared Resources

    Science.gov (United States)

    Al-Amin, S.

    2015-12-01

    Municipal water demands in growing population centers in the arid southwest US are typically met through increased groundwater withdrawals. Hydro-climatic uncertainties attributed to climate change and land use conversions may also alter demands and impact the replenishment of groundwater supply. Groundwater aquifers are not necessarily confined within municipal and management boundaries, and multiple diverse agencies may manage a shared resource in a decentralized approach, based on individual concerns and resources. The interactions among water managers, consumers, and the environment influence the performance of local management strategies and regional groundwater resources. This research couples an agent-based modeling (ABM) framework and a groundwater model to analyze the effects of different management approaches on shared groundwater resources. The ABM captures the dynamic interactions between household-level consumers and policy makers to simulate water demands under climate change and population growth uncertainties. The groundwater model is used to analyze the relative effects of management approaches on reducing demands and replenishing groundwater resources. The framework is applied for municipalities located in the Verde River Basin, Arizona that withdraw groundwater from the Verde Formation-Basin Fill-Carbonate aquifer system. Insights gained through this simulation study can be used to guide groundwater policy-making under changing hydro-climatic scenarios for a long-term planning horizon.

  9. PSO-tuned PID controller for coupled tank system via priority-based fitness scheme

    Science.gov (United States)

    Jaafar, Hazriq Izzuan; Hussien, Sharifah Yuslinda Syed; Selamat, Nur Asmiza; Abidin, Amar Faiz Zainal; Aras, Mohd Shahrieel Mohd; Nasir, Mohamad Na'im Mohd; Bohari, Zul Hasrizal

    2015-05-01

    The industrial applications of Coupled Tank System (CTS) are widely used especially in chemical process industries. The overall process is require liquids to be pumped, stored in the tank and pumped again to another tank. Nevertheless, the level of liquid in tank need to be controlled and flow between two tanks must be regulated. This paper presents development of an optimal PID controller for controlling the desired liquid level of the CTS. Two method of Particle Swarm Optimization (PSO) algorithm will be tested in optimizing the PID controller parameters. These two methods of PSO are standard Particle Swarm Optimization (PSO) and Priority-based Fitness Scheme in Particle Swarm Optimization (PFPSO). Simulation is conducted within Matlab environment to verify the performance of the system in terms of settling time (Ts), steady state error (SSE) and overshoot (OS). It has been demonstrated that implementation of PSO via Priority-based Fitness Scheme (PFPSO) for this system is potential technique to control the desired liquid level and improve the system performances compared with standard PSO.

  10. Fluorescent Biosensor for Phosphate Determination Based on Immobilized Polyfluorene-Liposomal Nanoparticles Coupled with Alkaline Phosphatase.

    Science.gov (United States)

    Kahveci, Zehra; Martínez-Tomé, Maria José; Mallavia, Ricardo; Mateo, C Reyes

    2017-01-11

    This work describes the development of a novel fluorescent biosensor based on the inhibition of alkaline phosphatase (ALP). The biosensor is composed of the enzyme ALP and the conjugated cationic polyfluorene HTMA-PFP. The working principle of the biosensor is based on the fluorescence quenching of this polyelectrolyte by p-nitrophenol (PNP), a product of the hydrolysis reaction of p-nitrophenyl phosphate (PNPP) catalyzed by ALP. Because HTMA-PFP forms unstable aggregates in buffer, with low fluorescence efficiency, previous stabilization of the polyelectrolyte was required before the development of the biosensor. HTMA-PFP was stabilized through its interaction with lipid vesicles to obtain stable blue-emitting nanoparticles (NPs). Fluorescent NPs were characterized, and the ability to be quenched by PNP was evaluated. These nanoparticles were coupled to ALP and entrapped in a sol-gel matrix to produce a biosensor that can serve as a screening platform to identify ALP inhibitors. The components of the biosensor were examined before and after sol-gel entrapment, and the biosensor was optimized to allow the determination of phosphate ion in aqueous medium.

  11. Biofuel Cell Based on Microscale Nanostructured Electrodes with Inductive Coupling to Rat Brain Neurons

    Science.gov (United States)

    Andoralov, Viktor; Falk, Magnus; Suyatin, Dmitry B.; Granmo, Marcus; Sotres, Javier; Ludwig, Roland; Popov, Vladimir O.; Schouenborg, Jens; Blum, Zoltan; Shleev, Sergey

    2013-11-01

    Miniature, self-contained biodevices powered by biofuel cells may enable a new generation of implantable, wireless, minimally invasive neural interfaces for neurophysiological in vivo studies and for clinical applications. Here we report on the fabrication of a direct electron transfer based glucose/oxygen enzymatic fuel cell (EFC) from genuinely three-dimensional (3D) nanostructured microscale gold electrodes, modified with suitable biocatalysts. We show that the process underlying the simple fabrication method of 3D nanostructured electrodes is based on an electrochemically driven transformation of physically deposited gold nanoparticles. We experimentally demonstrate that mediator-, cofactor-, and membrane-less EFCs do operate in cerebrospinal fluid and in the brain of a rat, producing amounts of electrical power sufficient to drive a self-contained biodevice, viz. 7 μW cm-2 in vitro and 2 μW cm-2 in vivo at an operating voltage of 0.4 V. Last but not least, we also demonstrate an inductive coupling between 3D nanobioelectrodes and living neurons.

  12. INS/GNSS Tightly-Coupled Integration Using Quaternion-Based AUPF for USV

    Directory of Open Access Journals (Sweden)

    Guoqing Xia

    2016-08-01

    Full Text Available This paper addresses the problem of integration of Inertial Navigation System (INS and Global Navigation Satellite System (GNSS for the purpose of developing a low-cost, robust and highly accurate navigation system for unmanned surface vehicles (USVs. A tightly-coupled integration approach is one of the most promising architectures to fuse the GNSS data with INS measurements. However, the resulting system and measurement models turn out to be nonlinear, and the sensor stochastic measurement errors are non-Gaussian and distributed in a practical system. Particle filter (PF, one of the most theoretical attractive non-linear/non-Gaussian estimation methods, is becoming more and more attractive in navigation applications. However, the large computation burden limits its practical usage. For the purpose of reducing the computational burden without degrading the system estimation accuracy, a quaternion-based adaptive unscented particle filter (AUPF, which combines the adaptive unscented Kalman filter (AUKF with PF, has been proposed in this paper. The unscented Kalman filter (UKF is used in the algorithm to improve the proposal distribution and generate a posterior estimates, which specify the PF importance density function for generating particles more intelligently. In addition, the computational complexity of the filter is reduced with the avoidance of the re-sampling step. Furthermore, a residual-based covariance matching technique is used to adapt the measurement error covariance. A trajectory simulator based on a dynamic model of USV is used to test the proposed algorithm. Results show that quaternion-based AUPF can significantly improve the overall navigation accuracy and reliability.

  13. Electromagnetically induced transparency in planar metamaterials based on guided mode resonance

    Science.gov (United States)

    Sun, Yaru; Chen, Hang; Li, Xiangjun; Hong, Zhi

    2017-06-01

    We present and numerically demonstrate a novel, electromagnetically induced transparency (EIT) in planar metamaterials (MMs) based on guided mode resonance (GMR). The unit cell of the MM consists of two metallic ring resonators. The GMR with high quality factor (Q) is achieved by changing the distance between the two rings of the MM. Narrow EIT-like spectral response is realized by coupling between a high Q GMR and a low Q dipolar resonance of the MM. Our work could provide another efficient way towards the realization of EIT with large group index using very simple structures.

  14. Impacts of Satellite-Based Snow Albedo Assimilation on Offline and Coupled Land Surface Model Simulations.

    Directory of Open Access Journals (Sweden)

    Tao Wang

    Full Text Available Seasonal snow cover in the Northern Hemisphere is the largest component of the terrestrial cryosphere and plays a major role in the climate system through strong positive feedbacks related to albedo. The snow-albedo feedback is invoked as an important cause for the polar amplification of ongoing and projected climate change, and its parameterization across models is an important source of uncertainty in climate simulations. Here, instead of developing a physical snow albedo scheme, we use a direct insertion approach to assimilate satellite-based surface albedo during the snow season (hereafter as snow albedo assimilation into the land surface model ORCHIDEE (ORganizing Carbon and Hydrology In Dynamic EcosystEms and assess the influences of such assimilation on offline and coupled simulations. Our results have shown that snow albedo assimilation in both ORCHIDEE and ORCHIDEE-LMDZ (a general circulation model of Laboratoire de Météorologie Dynamique improve the simulation accuracy of mean seasonal (October throughout May snow water equivalent over the region north of 40 degrees. The sensitivity of snow water equivalent to snow albedo assimilation is more pronounced in the coupled simulation than the offline simulation since the feedback of albedo on air temperature is allowed in ORCHIDEE-LMDZ. We have also shown that simulations of air temperature at 2 meters in ORCHIDEE-LMDZ due to snow albedo assimilation are significantly improved during the spring in particular over the eastern Siberia region. This is a result of the fact that high amounts of shortwave radiation during the spring can maximize its snow albedo feedback, which is also supported by the finding that the spatial sensitivity of temperature change to albedo change is much larger during the spring than during the autumn and winter. In addition, the radiative forcing at the top of the atmosphere induced by snow albedo assimilation during the spring is estimated to be -2.50 W m-2, the

  15. Education-based health inequalities in 18,000 Norwegian couples: the Nord-Trøndelag Health Study (HUNT

    Directory of Open Access Journals (Sweden)

    Nilsen Sara

    2012-11-01

    Full Text Available Abstract Background Education-based inequalities in health are well established, but they are usually studied from an individual perspective. However, many individuals are part of a couple. We studied education-based health inequalities from the perspective of couples where indicators of health were measured by subjective health, anxiety and depression. Methods A sample of 35,980 women and men (17,990 couples was derived from the Norwegian Nord-Trøndelag Health Study 1995–97 (HUNT 2. Educational data and family identification numbers were obtained from Statistics Norway. The dependent variables were subjective health (four-integer scale, anxiety (21-integer scale and depression (21-integer scale, which were captured using the Hospital Anxiety and Depression Scale. The dependent variables were rescaled from 0 to 100 where 100 was the worst score. Cross-sectional analyses were performed using two-level linear random effect regression models. Results The variance attributable to the couple level was 42% for education, 16% for subjective health, 19% for anxiety and 25% for depression. A one-year increase in education relative to that of one’s partner was associated with an improvement of 0.6 scale points (95% confidence interval = 0.5–0.8 in the subjective health score (within-couple coefficient. A one-year increase in a couple’s average education was associated with an improvement of 1.7 scale points (95% confidence interval = 1.6–1.8 in the subjective health score (between-couple coefficient. There were no education-based differences in the anxiety or depression scores when partners were compared, whereas there were substantial education-based differences between couples in all three outcome measures. Conclusions We found considerable clustering of education and health within couples, which highlighted the importance of the family environment. Our results support previous studies that report the mutual effects of spouses on

  16. Coupling Computer Codes for The Analysis of Severe Accident Using A Pseudo Shared Memory Based on MPI

    International Nuclear Information System (INIS)

    Cho, Young Chul; Park, Chang-Hwan; Kim, Dong-Min

    2016-01-01

    As there are four codes in-vessel analysis code (CSPACE), ex-vessel analysis code (SACAP), corium behavior analysis code (COMPASS), and fission product behavior analysis code, for the analysis of severe accident, it is complex to implement the coupling of codes with the similar methodologies for RELAP and CONTEMPT or SPACE and CAP. Because of that, an efficient coupling so called Pseudo shared memory architecture was introduced. In this paper, coupling methodologies will be compared and the methodology used for the analysis of severe accident will be discussed in detail. The barrier between in-vessel and ex-vessel has been removed for the analysis of severe accidents with the implementation of coupling computer codes with pseudo shared memory architecture based on MPI. The remaining are proper choice and checking of variables and values for the selected severe accident scenarios, e.g., TMI accident. Even though it is possible to couple more than two computer codes with pseudo shared memory architecture, the methodology should be revised to couple parallel codes especially when they are programmed using MPI

  17. Coupling Computer Codes for The Analysis of Severe Accident Using A Pseudo Shared Memory Based on MPI

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Chul; Park, Chang-Hwan; Kim, Dong-Min [FNC Technology Co., Yongin (Korea, Republic of)

    2016-10-15

    As there are four codes in-vessel analysis code (CSPACE), ex-vessel analysis code (SACAP), corium behavior analysis code (COMPASS), and fission product behavior analysis code, for the analysis of severe accident, it is complex to implement the coupling of codes with the similar methodologies for RELAP and CONTEMPT or SPACE and CAP. Because of that, an efficient coupling so called Pseudo shared memory architecture was introduced. In this paper, coupling methodologies will be compared and the methodology used for the analysis of severe accident will be discussed in detail. The barrier between in-vessel and ex-vessel has been removed for the analysis of severe accidents with the implementation of coupling computer codes with pseudo shared memory architecture based on MPI. The remaining are proper choice and checking of variables and values for the selected severe accident scenarios, e.g., TMI accident. Even though it is possible to couple more than two computer codes with pseudo shared memory architecture, the methodology should be revised to couple parallel codes especially when they are programmed using MPI.

  18. Different approaches to analyze the dipolar interaction effects on diluted and concentrated granular superparamagnetic systems

    Energy Technology Data Exchange (ETDEWEB)

    Moscoso-Londoño, O., E-mail: omoscoso@ifi.unicamp.br [Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas (UNICAMP), CEP13083-859 Campinas, São Paulo (Brazil); Tancredi, P. [Laboratorio de Sólidos Amorfos, INTECIN, Facultad de Ingeniería, Universidad de Buenos Aires (UBA), CONICET, C1063ACV Buenos Aires (Argentina); Muraca, D. [Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas (UNICAMP), CEP13083-859 Campinas, São Paulo (Brazil); Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC (UFABC), Av. Dos Estados, 5001, Santo André, SP (Brazil); Mendoza Zélis, P.; Coral, D.; Fernández van Raap, M.B. [Instituto de Física, Universidad Nacional de La Plata (UNLP), CONICET, CC.67, 1900 La Plata, Buenos Aires (Argentina); Wolff, U.; Neu, V.; Damm, C. [IFW Dresden, Leibniz Institute for Solid State and Materials Research, Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany); Oliveira, C.L.P. de [Instituto de Física, Universidade de São Paulo, São Paulo 05314970 (Brazil); Pirota, K.R. [Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas (UNICAMP), CEP13083-859 Campinas, São Paulo (Brazil); and others

    2017-04-15

    Controlled magnetic granular materials with different concentrations of magnetite nanoparticles immersed in a non-conducting polymer matrix were synthesized and, their macroscopic magnetic observables analyzed in order to advance towards a better understanding of the magnetic dipolar interactions and its effects on the obtained magnetic parameters. First, by means of X-ray diffraction, transmission electron microscopy, small angle X-ray scattering and X-ray absorption fine structure an accurate study of the structural properties was carried out. Then, the magnetic properties were analyzed by means of different models, including those that consider the magnetic interactions through long-range dipolar forces as: the Interacting Superparamagnetic Model (ISP) and the Vogel-Fulcher law (V-F). In systems with larger nanoparticle concentrations, magnetic results clearly indicate that the role played by the dipolar interactions affects the magnetic properties, giving rise to obtaining magnetic and structural parameters without physical meaning. Magnetic parameters as the effective anisotropic constant, magnetic moment relaxation time and mean blocking temperature, extracted from the application of the ISP model and V-F Law, were used to simulate the zero-field-cooling (ZFC) and field-cooling curves (FC). A comparative analysis of the simulated, fitted and experimental ZFC/FC curves suggests that the current models depict indeed our dilute granular systems. Notwithstanding, for concentrated samples, the ISP model infers that clustered nanoparticles are being interpreted as single entities of larger magnetic moment and volume, effect that is apparently related to a collective and complex magnetic moment dynamics within the cluster. - Highlights: • Nanoparticle architecture into matrices determines the composite magnetic response. • Magnetically diluted or compacted systems are useful to study magnetism at nanoscale. • Particle aggregation into the matrices was examined

  19. Off-equatorial current-driven instabilities ahead of approaching dipolarization fronts

    Science.gov (United States)

    Zhang, Xu; Angelopoulos, V.; Pritchett, P. L.; Liu, Jiang

    2017-05-01

    Recent kinetic simulations have revealed that electromagnetic instabilities near the ion gyrofrequency and slightly away from the equatorial plane can be driven by a current parallel to the magnetic field prior to the arrival of dipolarization fronts. Such instabilities are important because of their potential contribution to global electromagnetic energy conversion near dipolarization fronts. Of the several instabilities that may be consistent with such waves, the most notable are the current-driven electromagnetic ion cyclotron instability and the current-driven kink-like instability. To confirm the existence and characteristics of these instabilities, we used observations by two Time History of Events and Macroscale Interactions during Substorms satellites, one near the neutral sheet observing dipolarization fronts and the other at the boundary layer observing precursor waves and currents. We found that such instabilities with monochromatic signatures are rare, but one of the few cases was selected for further study. Two different instabilities, one at about 0.3 Hz and the other at a much lower frequency, 0.02 Hz, were seen in the data from the off-equatorial spacecraft. A parallel current attributed to an electron beam coexisted with the waves. Our instability analysis attributes the higher-frequency instability to a current-driven ion cyclotron instability and the lower frequency instability to a kink-like instability. The current-driven kink-like instability we observed is consistent with the instabilities observed in the simulation. We suggest that the currents needed to excite these low-frequency instabilities are so intense that the associated electron beams are easily thermalized and hence difficult to observe.

  20. Synchronization of pairwise-coupled, identical, relaxation oscillators based on metal-insulator phase transition devices: A model study

    Science.gov (United States)

    Parihar, Abhinav; Shukla, Nikhil; Datta, Suman; Raychowdhury, Arijit

    2015-02-01

    Computing with networks of synchronous oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled oscillatory systems. Of particular interest are compact and low-power relaxation oscillators that have been recently demonstrated using MIT (metal-insulator-transition) devices using properties of correlated oxides. Further the computational capability of pairwise coupled relaxation oscillators has also been shown to outperform traditional Boolean digital logic circuits. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation oscillators implemented with MIT devices. We focus on two implementations of the oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (RC) and a capacitive (CC) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of RC and CC, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled

  1. Exploration of mild copper-mediated coupling of organotrifluoroborates in the synthesis of thiirane-based inhibitors of matrix metalloproteinases.

    Science.gov (United States)

    Testero, Sebastian A; Bouley, Renee; Fisher, Jed F; Chang, Mayland; Mobashery, Shahriar

    2011-05-01

    The copper-mediated and non-basic oxidative cross-coupling of organotrifluoroborates with phenols was applied to elaboration of the structures of thiirane-based inhibitors of matrix metalloproteinases. By revision of the synthetic sequence to allow this cross-coupling as the final step, and taking advantage of the neutral nature of organotrifluoroborate cross-coupling, a focussed series of inhibitors showing aryloxy and alkenyloxy replacement of the phenoxy substituent was prepared. This reaction shows exceptional promise as an alternative to the classic copper-mediated but strongly basic Ullmann reaction, for the diversification of ether segments within base-labile lead structures. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures

    KAUST Repository

    Bracco, Silvia; Beretta, Mario; Cattaneo, Alice Silvia; Comotti, Angiolina; Falqui, Andrea; Zhao, Ke; Rogers, Charles T.; Sozzani, Piero

    2015-01-01

    New mesoporous covalent frameworks, based on hybrid fluorinated organosilicas, were prepared to realize a periodic architecture of fast molecular rotors containing dynamic dipoles in their structure. The mobile elements, designed on the basis of fluorinated p-divinylbenzene moieties, were integrated into the robust covalent structure through siloxane bonds, and showed not only the rapid dynamics of the aromatic rings (ca. 108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Furthermore, the mesochannels are open and accessible to diffusing in gas molecules, and rotor mobility could be individually regulated by I2 vapors. The iodine enters the channels of the periodic structure and reacts with the pivotal double bonds of the divinyl-fluoro-phenylene rotors, affecting their motion and the dielectric properties. Oriented molecular rotors: Fluorinated molecular rotors (see picture) were engineered in mesoporous hybrid organosilica architectures with crystalline order in their walls. The rotor dynamics was established by magic angle spinning NMR and dielectric measurements, indicating a rotational correlation time as short as 10-9 s at 325 K. The dynamics was modulated by I2 vapors entering the pores.

  3. Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures

    KAUST Repository

    Bracco, Silvia

    2015-02-16

    New mesoporous covalent frameworks, based on hybrid fluorinated organosilicas, were prepared to realize a periodic architecture of fast molecular rotors containing dynamic dipoles in their structure. The mobile elements, designed on the basis of fluorinated p-divinylbenzene moieties, were integrated into the robust covalent structure through siloxane bonds, and showed not only the rapid dynamics of the aromatic rings (ca. 108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Furthermore, the mesochannels are open and accessible to diffusing in gas molecules, and rotor mobility could be individually regulated by I2 vapors. The iodine enters the channels of the periodic structure and reacts with the pivotal double bonds of the divinyl-fluoro-phenylene rotors, affecting their motion and the dielectric properties. Oriented molecular rotors: Fluorinated molecular rotors (see picture) were engineered in mesoporous hybrid organosilica architectures with crystalline order in their walls. The rotor dynamics was established by magic angle spinning NMR and dielectric measurements, indicating a rotational correlation time as short as 10-9 s at 325 K. The dynamics was modulated by I2 vapors entering the pores.

  4. Absolute carrier phase effects in the two-color excitation of dipolar molecules

    International Nuclear Information System (INIS)

    Brown, Alex; Meath, W.J.; Kondo, A.E.

    2002-01-01

    The pump-probe excitation of a two-level dipolar (d≠0) molecule, where the pump frequency is tuned to the energy level separation while the probe frequency is extremely small, is examined theoretically as an example of absolute phase control of excitation processes. The state populations depend on the probe field's absolute carrier phase but are independent of the pump field's absolute carrier phase. Interestingly, the absolute phase effects occur for pulse durations much longer and field intensities much weaker than those required to see such effects in single pulse excitation

  5. Fluctuation-dissipation theorem in an isolated system of quantum dipolar bosons after a quench.

    Science.gov (United States)

    Khatami, Ehsan; Pupillo, Guido; Srednicki, Mark; Rigol, Marcos

    2013-08-02

    We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find indications that fluctuation-dissipation relations hold if the system is nonintegrable after the quench, as well as if it is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. On the other hand, we find indications that they fail if the system is integrable both before and after quenching.

  6. Synthesis and 1,3-Dipolar Cycloaddition Reactions of Chiral Maleimides

    Directory of Open Access Journals (Sweden)

    Lubor Fisera

    1997-02-01

    Full Text Available New routes to the synthesis of various novel chiral maleimides are described. The oxabicyclic anhydride 2 readily available exo-Diels-Alder adduct of furan and maleic anhydride was used as a vehicle, which in turn reacted with hydrochlorides of amino acids 3a-f in the presence of Et3N with release of furan to give the requisite novel chiral imides 4a-f in good to moderate yields. The stereoselectivity of 1,3-dipolar cycloaddition of nitrile oxides with prepared chiral imides 4a-f is investigated.

  7. Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

    Directory of Open Access Journals (Sweden)

    Andreas Gansäuer

    2014-07-01

    Full Text Available An operationally simple, convenient, and mild strategy for the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute ‘second-generation’ functionalized titanocene building blocks for further synthetic elaboration. Our synthesis is modular and large numbers of the complexes can in principle be prepared in short periods of time. Some of the triazole-substituted titanocenes display high cyctotoxic activity against BJAB cells. Comparison of the most active complexes allows the identification of structural features essential for biological activity.

  8. Characteristics of ion distribution functions in dipolarizing flux bundles: Event studies

    Science.gov (United States)

    Runov, A.; Angelopoulos, V.; Artemyev, A.; Birn, J.; Pritchett, P. L.; Zhou, X.-Z.

    2017-06-01

    Taking advantage of multipoint observations from a repeating configuration of the five Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes separated by 1 to 2 Earth radii (RE) along X, Y, and Z in the geocentric solar magnetospheric system (GSM), we study ion distribution functions collected by the probes during three dipolarizing flux bundle (DFB) events observed at geocentric distances 9 energy and twice the thermal energy, although the distribution in the ambient plasma sheet was isotropic. The anisotropic ion distribution in DFBs injected toward the inner magnetosphere may provide the free energy for waves and instabilities, which are important elements of particle energization.

  9. Fluctuation and dipolar interaction effects on the pinning of domain walls

    International Nuclear Information System (INIS)

    Chui, S.T.

    2001-01-01

    We discuss the effect of the dipolar interaction on the pinning of domain walls. Domain walls are usually pinned near the boundaries between grains. Magnetic charges accumulated at the domain wall make the wall more unstable and easier to depin. We discuss how the grain-orientation and thermal fluctuations affect these magnetic charges and hence the depinning of the domain walls. Our results are illustrated by finite temperature Monte Carlo simulation on periodic arrays of large cells separated by walls consisting of faces of pyramids

  10. Anisotropic properties of phase separation in two-component dipolar Bose-Einstein condensates

    Science.gov (United States)

    Wang, Wei; Li, Jinbin

    2018-03-01

    Using Crank-Nicolson method, we calculate ground state wave functions of two-component dipolar Bose-Einstein condensates (BECs) and show that, due to dipole-dipole interaction (DDI), the condensate mixture displays anisotropic phase separation. The effects of DDI, inter-component s-wave scattering, strength of trap potential and particle numbers on the density profiles are investigated. Three types of two-component profiles are present, first cigar, along z-axis and concentric torus, second pancake (or blood cell), in xy-plane, and two non-uniform ellipsoid, separated by the pancake and third two dumbbell shapes.

  11. Parallel implementation of multireference coupled-cluster theories based on the reference-level parallelism

    Energy Technology Data Exchange (ETDEWEB)

    Brabec, Jiri; Pittner, Jiri; van Dam, Hubertus JJ; Apra, Edoardo; Kowalski, Karol

    2012-02-01

    A novel algorithm for implementing general type of multireference coupled-cluster (MRCC) theory based on the Jeziorski-Monkhorst exponential Ansatz [B. Jeziorski, H.J. Monkhorst, Phys. Rev. A 24, 1668 (1981)] is introduced. The proposed algorithm utilizes processor groups to calculate the equations for the MRCC amplitudes. In the basic formulation each processor group constructs the equations related to a specific subset of references. By flexible choice of processor groups and subset of reference-specific sufficiency conditions designated to a given group one can assure optimum utilization of available computing resources. The performance of this algorithm is illustrated on the examples of the Brillouin-Wigner and Mukherjee MRCC methods with singles and doubles (BW-MRCCSD and Mk-MRCCSD). A significant improvement in scalability and in reduction of time to solution is reported with respect to recently reported parallel implementation of the BW-MRCCSD formalism [J.Brabec, H.J.J. van Dam, K. Kowalski, J. Pittner, Chem. Phys. Lett. 514, 347 (2011)].

  12. Coupling Fine-Scale Root and Canopy Structure Using Ground-Based Remote Sensing

    Directory of Open Access Journals (Sweden)

    Brady S. Hardiman

    2017-02-01

    Full Text Available Ecosystem physical structure, defined by the quantity and spatial distribution of biomass, influences a range of ecosystem functions. Remote sensing tools permit the non-destructive characterization of canopy and root features, potentially providing opportunities to link above- and belowground structure at fine spatial resolution in functionally meaningful ways. To test this possibility, we employed ground-based portable canopy LiDAR (PCL and ground penetrating radar (GPR along co-located transects in forested sites spanning multiple stages of ecosystem development and, consequently, of structural complexity. We examined canopy and root structural data for coherence (i.e., correlation in the frequency of spatial variation at multiple spatial scales ≤10 m within each site using wavelet analysis. Forest sites varied substantially in vertical canopy and root structure, with leaf area index and root mass more becoming even vertically as forests aged. In all sites, above- and belowground structure, characterized as mean maximum canopy height and root mass, exhibited significant coherence at a scale of 3.5–4 m, and results suggest that the scale of coherence may increase with stand age. Our findings demonstrate that canopy and root structure are linked at characteristic spatial scales, which provides the basis to optimize scales of observation. Our study highlights the potential, and limitations, for fusing LiDAR and radar technologies to quantitatively couple above- and belowground ecosystem structure.

  13. Calculation of marine propeller static strength based on coupled BEM/FEM

    Directory of Open Access Journals (Sweden)

    YE Liyu

    2017-10-01

    Full Text Available [Objectives] The reliability of propeller stress has a great influence on the safe navigation of a ship. To predict propeller stress quickly and accurately,[Methods] a new numerical prediction model is developed by coupling the Boundary Element Method(BEMwith the Finite Element Method (FEM. The low order BEM is used to calculate the hydrodynamic load on the blades, and the Prandtl-Schlichting plate friction resistance formula is used to calculate the viscous load. Next, the calculated hydrodynamic load and viscous correction load are transmitted to the calculation of the Finite Element as surface loads. Considering the particularity of propeller geometry, a continuous contact detection algorithm is developed; an automatic method for generating the finite element mesh is developed for the propeller blade; a code based on the FEM is compiled for predicting blade stress and deformation; the DTRC 4119 propeller model is applied to validate the reliability of the method; and mesh independence is confirmed by comparing the calculated results with different sizes and types of mesh.[Results] The results show that the calculated blade stress and displacement distribution are reliable. This method avoids the process of artificial modeling and finite element mesh generation, and has the advantages of simple program implementation and high calculation efficiency.[Conclusions] The code can be embedded into the code of theoretical and optimized propeller designs, thereby helping to ensure the strength of designed propellers and improve the efficiency of propeller design.

  14. All-fiber radially/azimuthally polarized lasers based on mode coupling of tapered fibers.

    Science.gov (United States)

    Mao, Dong; He, Zhiwen; Lu, Hua; Li, Mingkun; Zhang, Wending; Cui, Xiaoqi; Jiang, Biqiang; Zhao, Jianlin

    2018-04-01

    We demonstrate a mode converter with an insertion loss of 0.36 dB based on mode coupling of tapered single-mode and two-mode fibers, and realize all-fiber flexible cylindrical vector lasers at 1550 nm. Attributing to the continuous distribution of a tangential electric field at taper boundaries, the laser is switchable between the radially and azimuthally polarized states by adjusting the input polarization. In the temporal domain, the operation is controllable among continuous-wave, Q-switched, and mode-locked statuses by changing the saturable absorber or pump strength. The duration of Q-switched radially/azimuthally polarized laser spans from 10.4/10.8 to 6/6.4 μs at the pump range of 38 to 58 mW, while that of the mode-locked pulse varies from 39.2/31.9 to 5.6/5.2 ps by controlling the laser bandwidth. The proposed laser combines the features of a cylindrical vector beam, a fiber laser, and an ultrafast pulse, providing a special and cost-effective source for practical applications.

  15. On-chip plasmon-induced transparency based on plasmonic coupled nanocavities.

    Science.gov (United States)

    Zhu, Yu; Hu, Xiaoyong; Yang, Hong; Gong, Qihuang

    2014-01-17

    On-chip plasmon-induced transparency offers the possibility of realization of ultrahigh-speed information processing chips. Unfortunately, little experimental progress has been made to date because it is difficult to obtain on-chip plasmon-induced transparency using only a single meta-molecule in plasmonic circuits. Here, we report a simple and efficient strategy to realize on-chip plasmon-induced transparency in a nanoscale U-shaped plasmonic waveguide side-coupled nanocavity pair. High tunability in the transparency window is achieved by covering the pair with different organic polymer layers. It is possible to realize ultrafast all-optical tunability based on pump light-induced refractive index change of a graphene cover layer. Compared with previous reports, the overall feature size of the plasmonic nanostructure is reduced by more than three orders of magnitude, while ultrahigh tunability of the transparency window is maintained. This work also provides a superior platform for the study of the various physical effects and phenomena of nonlinear optics and quantum optics.

  16. Analytical coupled modeling of a magneto-based acoustic metamaterial harvester

    Science.gov (United States)

    Nguyen, H.; Zhu, R.; Chen, J. K.; Tracy, S. L.; Huang, G. L.

    2018-05-01

    Membrane-type acoustic metamaterials (MAMs) have demonstrated unusual capacity in controlling low-frequency sound transmission, reflection, and absorption. In this paper, an analytical vibro-acoustic-electromagnetic coupling model is developed to study MAM harvester sound absorption, energy conversion, and energy harvesting behavior under a normal sound incidence. The MAM harvester is composed of a prestressed membrane with an attached rigid mass, a magnet coil, and a permanent magnet coin. To accurately capture finite-dimension rigid mass effects on the membrane deformation under the variable magnet force, a theoretical model based on the deviating acoustic surface Green’s function approach is developed by considering the acoustic near field and distributed effective shear force along the interfacial boundary between the mass and the membrane. The accuracy and capability of the theoretical model is verified through comparison with the finite element method. In particular, sound absorption, acoustic-electric energy conversion, and harvesting coefficient are quantitatively investigated by varying the weight and size of the attached mass, prestress and thickness of the membrane. It is found that the highest achievable conversion and harvesting coefficients can reach up to 48%, and 36%, respectively. The developed model can serve as an efficient tool for designing MAM harvesters.

  17. Coupled Simulation of Thermomagnetic Energy Generation Based on NiMnGa Heusler Alloy Films

    Science.gov (United States)

    Kohl, Manfred; Gueltig, Marcel; Wendler, Frank

    2018-03-01

    This paper presents a simulation model for the coupled dynamic properties of thermomagnetic generators based on magnetic shape memory alloy (MSMA) films. MSMA thermomagnetic generators exploit the large abrupt temperature-induced change of magnetization at the first- or second-order magnetic transition as well as the short heat transfer times due to the large surface-to-volume ratio of films. These properties allow for resonant self-actuation of freely movable MSMA cantilever devices showing thermomagnetic duty cycles in the order of 10 ms duration, which matches with the period of oscillatory motion. We present a numerical analysis of the energy conversion processes to understand the effect of design parameters on efficiency and power output. A lumped element model is chosen to describe the time dependence of MSMA cantilever deflection and of temperature profiles as well as the magnitude and phase dependency of magnetization change. The simulation model quantitatively describes experimentally observed oscillatory motion and resulting power output in the order of 100 mW cm-3. Furthermore, it predicts a power output of 490 mW cm-3 for advanced film materials with temperature-dependent change of magnetization Δ M/Δ T of 4 A m2 (kg K)-1, which challenges state-of-the-art thermoelectric devices.

  18. An Optimal Design of Multiple Antenna Positions on Mobile Devices Based on Mutual Coupling Analysis

    Directory of Open Access Journals (Sweden)

    Peerapong Uthansakul

    2011-01-01

    Full Text Available The topic of practical implementation of multiple antenna systems for mobile communications has recently gained a lot of attention. Due to the area constraint on a mobile device, the problem of how to design such a system in order to achieve the best benefit is still a huge challenge. In this paper, genetic algorithm (GA is used to find the optimal antenna positions on a mobile device. Two cases of 3×3 and 4×4 MIMO systems are undertaken. The effect of mutual coupling based on Z-parameter is the main factor to determine the MIMO capacity concerning the objective function of GA search. The results confirm the success of the proposed method to design MIMO antenna positions on a mobile device. Moreover, this paper introduces the method to design the antenna positions for the condition of nondeterministic channel. The concern of channel variation has been included in the process of finding optimal MIMO antenna positions. The results suggest that the averaging position from all GA solutions according to all channel conditions provides the most acceptable benefit.

  19. Buckling analysis of orthotropic protein microtubules under axial and radial compression based on couple stress theory.

    Science.gov (United States)

    Beni, Yaghoub Tadi; Zeverdejani, M Karimi; Mehralian, Fahimeh

    2017-10-01

    Protein microtubules (MTs) are one of the important intercellular components and have a vital role in the stability and strength of the cells. Due to applied external loads, protein microtubules may be involved buckling phenomenon. Due to impact of protein microtubules in cell reactions, it is important to determine their critical buckling load. Considering nature of protein microtubules, various parameters are effective on microtubules buckling. The small size of microtubules and also lack of uniformity of MTs properties in different directions caused the necessity of accuracy in the analysis of these bio-structure. In fact, microtubules must be considered as a size dependent cylinder, which behave as an orthotropic material. Hence, in the present work using first-order shear deformation model (FSDT), the buckling equations of anisotropic MTs are derived based on new modified couple stress theory (NMCST). After solving the stability equations, the influences of various parameters are measured on the MTs critical buckling load. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Cluster Synchronization of Diffusively Coupled Nonlinear Systems: A Contraction-Based Approach

    Science.gov (United States)

    Aminzare, Zahra; Dey, Biswadip; Davison, Elizabeth N.; Leonard, Naomi Ehrich

    2018-04-01

    Finding the conditions that foster synchronization in networked nonlinear systems is critical to understanding a wide range of biological and mechanical systems. However, the conditions proved in the literature for synchronization in nonlinear systems with linear coupling, such as has been used to model neuronal networks, are in general not strict enough to accurately determine the system behavior. We leverage contraction theory to derive new sufficient conditions for cluster synchronization in terms of the network structure, for a network where the intrinsic nonlinear dynamics of each node may differ. Our result requires that network connections satisfy a cluster-input-equivalence condition, and we explore the influence of this requirement on network dynamics. For application to networks of nodes with FitzHugh-Nagumo dynamics, we show that our new sufficient condition is tighter than those found in previous analyses that used smooth or nonsmooth Lyapunov functions. Improving the analytical conditions for when cluster synchronization will occur based on network configuration is a significant step toward facilitating understanding and control of complex networked systems.

  1. Measurements of relative chemical shift tensor orientations in solid-state NMR: new slow magic angle spinning dipolar recoupling experiments.

    Science.gov (United States)

    Jurd, Andrew P S; Titman, Jeremy J

    2009-08-28

    Solid-state NMR experiments can be used to determine conformational parameters, such as interatomic distances and torsion angles. The latter can be obtained from measurements of the relative orientation of two chemical shift tensors, if the orientation of these with respect to the surrounding bonds is known. In this paper, a new rotor-synchronized magic angle spinning (MAS) dipolar correlation experiment is described which can be used in this way. Because the experiment requires slow MAS rates, a novel recoupling sequence, designed using symmetry principles, is incorporated into the mixing period. This recoupling sequence is based in turn on a new composite cyclic pulse referred to as COAST (for combined offset and anisotropy stabilization). The new COAST-C7(2)(1) sequence is shown to give good theoretical and experimental recoupling efficiency, even when the CSA far exceeds the MAS rate. In this regime, previous recoupling sequences, such as POST-C7(2)(1), exhibit poor recoupling performance. The effectiveness of the new method has been explored by a study of the dipeptide L-phenylalanyl-L-phenylalanine.

  2. Communication: Proton NMR dipolar-correlation effect as a method for investigating segmental diffusion in polymer melts

    International Nuclear Information System (INIS)

    Lozovoi, A.; Mattea, C.; Stapf, S.; Herrmann, A.; Rössler, E. A.; Fatkullin, N.

    2016-01-01

    A simple and fast method for the investigation of segmental diffusion in high molar mass polymer melts is presented. The method is based on a special function, called proton dipolar-correlation build-up function, which is constructed from Hahn Echo signals measured at times t and t/2. The initial rise of this function contains additive contributions from both inter- and intramolecular magnetic dipole-dipole interactions. The intermolecular contribution depends on the relative mean squared displacements (MSDs) of polymer segments from different macromolecules, while the intramolecular part reflects segmental reorientations. Separation of both contributions via isotope dilution provides access to segmental displacements in polymer melts at millisecond range, which is hardly accessible by other methods. The feasibility of the method is illustrated by investigating protonated and deuterated polybutadiene melts with molecular mass 196 000 g/mol at different temperatures. The observed exponent of the power law of the segmental MSD is close to 0.32 ± 0.03 at times when the root MSD is in between 45 Å and 75 Å, and the intermolecular proton dipole-dipole contribution to the total proton Hahn Echo NMR signal is larger than 50% and increases with time.

  3. Photoinduced Bioorthogonal 1,3-Dipolar Poly-cycloaddition Promoted by Oxyanionic Substrates for Spatiotemporal Operation of Molecular Glues.

    Science.gov (United States)

    Hatano, Junichi; Okuro, Kou; Aida, Takuzo

    2016-01-04

    PGlue(PZ), a pyrazoline (PZ)-based fluorescent adhesive which can be generated spatiotemporally in living systems, was developed. Since PGlue(PZ) carries many guanidinium ion (Gu(+)) pendants, it strongly adheres to various oxyanionic substrates through a multivalent salt-bridge interaction. PGlue(PZ) is given by bioorthogonal photopolymerization of a Gu(+)-appended monomer (Glue(TZ)), bearing tetrazole (TZ) and olefinic termini. Upon exposure to UV light, Glue(TZ) transforms into a nitrileimine (NI) intermediate (Glue(NI)), which is eligible for 1,3-dipolar polycycloaddition. However, Glue(NI) in aqueous media can concomitantly be deactivated into Glue(WA) by the addition of water, and the polymerization hardly occurs unless Glue(NI) is concentrated. We found that, even under high dilution, Glue(NI) is concentrated on oxyanionic substrates to a sufficient level for the polymerization, so that their surfaces can be point-specifically functionalized with PGlue(PZ) by the use of a focused beam of UV light. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. We-Language and Sustained Reductions in Drinking in Couple-Based Treatment for Alcohol Use Disorders.

    Science.gov (United States)

    Hallgren, Kevin A; McCrady, Barbara S

    2016-03-01

    Couple-based treatments for alcohol use disorders (AUDs) produce higher rates of abstinence than individual-based treatments and posit that active involvement of both identified patients (IPs) and significant others (SOs) is partly responsible for these improvements. Separate research on couples' communication has suggested that pronoun usage can indicate a communal approach to coping with health-related problems. The present study tested whether communal coping, indicated by use of more first-person plural pronouns ("we" language), fewer second-person pronouns ("you" language), and fewer first-person singular pronouns ("I" language), predicted improvements in abstinence in couple-based AUD treatment. Pronoun use was measured in first- and mid-treatment sessions for 188 heterosexual couples in four clinical trials of alcohol behavioral couple therapy (ABCT). Percentages of days abstinent were assessed during treatment and over a 6-month follow-up period. Greater IP and SO "we" language during both sessions was correlated with greater improvement in abstinent days during treatment. Greater SO "we" language during first- and mid-treatment sessions was correlated with greater improvement in abstinence at follow-up. Greater use of IP and SO "you" and "I" language had mixed correlations with abstinence, typically being unrelated to or predicting less improvement in abstinence. When all pronoun variables were entered into regression models, only greater IP "we" langue and lower IP "you" language predicted improvements in abstinence during treatment, and only SO "we" language predicted improvements during follow-up. Most pronoun categories had little or no association with baseline relationship distress. Results suggest that communal coping predicts better abstinence outcomes in couple-based AUD treatment. © 2015 Family Process Institute.

  5. Attitudes of serodiscordant couples towards antiretroviral-based HIV prevention strategies in Kenya: a qualitative study.

    Science.gov (United States)

    Fowler, Nikola; Arkell, Paul; Abouyannis, Michael; James, Catherine; Roberts, Lesley

    2014-01-01

    using condoms if ARV-based prevention methods were available. Findings from the study indicate that TasP may represent a more viable approach to HIV prevention in Kenya than PrEP. Couples' preferences, however, may differ depending on local attitudes towards prophylaxis and health locus of control.

  6. The simulation of electrostatic coupling intra-body communication based on the finite-element method

    Institute of Scientific and Technical Information of China (English)

    Song Yong; Zhang Kai; Yang Guang; Zhu Kang; Hao Qun

    2011-01-01

    In this paper, investigation has been done in the computer simulation of the electrostatic coupling IBC by using the developed finite-element models, in which a. the incidence and reflection of electronic signal in the upper arm model were analyzed by using the theory of electromagnetic wave; b. the finite-element models of electrostatic coupling IBC were developed by using the electromagnetic analysis package of ANSYS software; c. the signal attenuation of electrostatic coupling IBC were simulated under the conditions of different signal frequencies, electrodes directions, electrodes sizes and transmission distances. Finally, some important conclusions are deduced on the basis of simulation results.

  7. GIS coupled Multiple Criteria based Decision Support for Classification of Urban Coastal Areas in India

    Science.gov (United States)

    Dhiman, R.; Kalbar, P.; Inamdar, A. B.

    2017-12-01

    Coastal area classification in India is a challenge for federal and state government agencies due to fragile institutional framework, unclear directions in implementation of costal regulations and violations happening at private and government level. This work is an attempt to improvise the objectivity of existing classification methods to synergies the ecological systems and socioeconomic development in coastal cities. We developed a Geographic information system coupled Multi-criteria Decision Making (GIS-MCDM) approach to classify urban coastal areas where utility functions are used to transform the costal features into quantitative membership values after assessing the sensitivity of urban coastal ecosystem. Furthermore, these membership values for costal features are applied in different weighting schemes to derive Coastal Area Index (CAI) which classifies the coastal areas in four distinct categories viz. 1) No Development Zone, 2) Highly Sensitive Zone, 3) Moderately Sensitive Zone and 4) Low Sensitive Zone based on the sensitivity of urban coastal ecosystem. Mumbai, a coastal megacity in India is used as case study for demonstration of proposed method. Finally, uncertainty analysis using Monte Carlo approach to validate the sensitivity of CAI under specific multiple scenarios is carried out. Results of CAI method shows the clear demarcation of coastal areas in GIS environment based on the ecological sensitivity. CAI provides better decision support for federal and state level agencies to classify urban coastal areas according to the regional requirement of coastal resources considering resilience and sustainable development. CAI method will strengthen the existing institutional framework for decision making in classification of urban coastal areas where most effective coastal management options can be proposed.

  8. Adapting a couple-based intimacy enhancement intervention to breast cancer: A developmental study.

    Science.gov (United States)

    Reese, Jennifer Barsky; Porter, Laura S; Casale, Kristen E; Bantug, Elissa T; Bober, Sharon L; Schwartz, Sharon C; Smith, Katherine Clegg

    2016-10-01

    Sexual concerns continue to be poorly addressed for women treated for breast cancer and evidence-based interventions that adequately address these concerns are scarce. The objective of this study was to adapt a telephone-based intimacy enhancement intervention, previously tested in couples facing colorectal cancer, to the needs of women with breast cancer through qualitative focus groups, cognitive interviews, and expert review. Three semistructured qualitative focus groups in partnered posttreatment breast cancer survivors (n = 15) reporting sexual concerns were conducted to investigate experiences of breast cancer-related sexual concerns and intervention preferences. Focus group data were coded using the framework approach to qualitative analysis; 8 key themes were identified and used to develop the content and format of the intervention. Feedback from cognitive interviews with study-naïve breast cancer survivors (n = 4) and expert review of materials were also incorporated in finalizing the intervention materials. Qualitative findings centered on the impact of breast cancer and its treatment on women's sexuality and on the intimate relationship, experiences of helpful and unhelpful coping methods, and explicit intervention preferences. Focus group data were particularly helpful in identifying the scope of educational topics and in determining how to structure intervention skills practice (e.g., intimacy-related communication) to be optimally relevant and helpful for both women and their partners. Cognitive interview feedback helped refine intervention materials. An intimacy enhancement intervention was adapted for women with breast cancer and their partners. This intervention offers a promising, potentially disseminable approach to addressing breast cancer-related sexual concerns. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  9. A Newton-based Jacobian-free approach for neutronic-Monte Carlo/thermal-hydraulic static coupled analysis

    International Nuclear Information System (INIS)

    Mylonakis, Antonios G.; Varvayanni, M.; Catsaros, N.

    2017-01-01

    Highlights: •A Newton-based Jacobian-free Monte Carlo/thermal-hydraulic coupling approach is introduced. •OpenMC is coupled with COBRA-EN with a Newton-based approach. •The introduced coupling approach is tested in numerical experiments. •The performance of the new approach is compared with the traditional “serial” coupling approach. -- Abstract: In the field of nuclear reactor analysis, multi-physics calculations that account for the bonded nature of the neutronic and thermal-hydraulic phenomena are of major importance for both reactor safety and design. So far in the context of Monte-Carlo neutronic analysis a kind of “serial” algorithm has been mainly used for coupling with thermal-hydraulics. The main motivation of this work is the interest for an algorithm that could maintain the distinct treatment of the involved fields within a tight coupling context that could be translated into higher convergence rates and more stable behaviour. This work investigates the possibility of replacing the usually used “serial” iteration with an approximate Newton algorithm. The selected algorithm, called Approximate Block Newton, is actually a version of the Jacobian-free Newton Krylov method suitably modified for coupling mono-disciplinary solvers. Within this Newton scheme the linearised system is solved with a Krylov solver in order to avoid the creation of the Jacobian matrix. A coupling algorithm between Monte-Carlo neutronics and thermal-hydraulics based on the above-mentioned methodology is developed and its performance is analysed. More specifically, OpenMC, a Monte-Carlo neutronics code and COBRA-EN, a thermal-hydraulics code for sub-channel and core analysis, are merged in a coupling scheme using the Approximate Block Newton method aiming to examine the performance of this scheme and compare with that of the “traditional” serial iterative scheme. First results show a clear improvement of the convergence especially in problems where significant

  10. Development of New Open-Shell Perturbation and Coupled-Cluster Theories Based on Symmetric Spin Orbitals

    Science.gov (United States)

    Lee, Timothy J.; Arnold, James O. (Technical Monitor)

    1994-01-01

    A new spin orbital basis is employed in the development of efficient open-shell coupled-cluster and perturbation theories that are based on a restricted Hartree-Fock (RHF) reference function. The spin orbital basis differs from the standard one in the spin functions that are associated with the singly occupied spatial orbital. The occupied orbital (in the spin orbital basis) is assigned the delta(+) = 1/square root of 2(alpha+Beta) spin function while the unoccupied orbital is assigned the delta(-) = 1/square root of 2(alpha-Beta) spin function. The doubly occupied and unoccupied orbitals (in the reference function) are assigned the standard alpha and Beta spin functions. The coupled-cluster and perturbation theory wave functions based on this set of "symmetric spin orbitals" exhibit much more symmetry than those based on the standard spin orbital basis. This, together with interacting space arguments, leads to a dramatic reduction in the computational cost for both coupled-cluster and perturbation theory. Additionally, perturbation theory based on "symmetric spin orbitals" obeys Brillouin's theorem provided that spin and spatial excitations are both considered. Other properties of the coupled-cluster and perturbation theory wave functions and models will be discussed.

  11. Effect of ferrite addition above the base ferrite on the coupling factor of wireless power transfer for vehicle applications

    DEFF Research Database (Denmark)

    Batra, Tushar; Schaltz, Erik; Ahn, Seungyoung

    2015-01-01

    and reduce magnetic emissions to the surroundings. Effect of adding extra ferrite above the base ferrite at different physical locations on the self-inductance, mutual inductance and coupling factor is under investigation in this paper. The addition can increase or decrease the mutual inductance depending...

  12. A PC-Based Tool for Coupled CFD and CSD Simulation of Blast-Barrier Responses

    National Research Council Canada - National Science Library

    Chen, Zen; Bewick, Bryan; Salim, Hani A; Kiger, Sam A; Dinan, Robert J; Hu, Wenquin

    2006-01-01

    ... for predicting the responses of a blast barrier. An axisymmetrical model is formulated using a coupled CFD and CSD simulation procedure designed via the Material Point Method in spatial discretization...

  13. Coupled Interfacial Tension and Phase Behavior Model Based on Micellar Curvatures

    KAUST Repository

    Torrealba, V. A.; Johns, R. T.

    2017-01-01

    This article introduces a consistent and robust model that predicts interfacial tensions for all microemulsion Winsor types and overall compositions. The model incorporates film bending arguments and Huh's equation and is coupled to phase behavior

  14. Profiles of dyadic adjustment for advanced prostate cancer to inform couple-based intervention.

    Science.gov (United States)

    Elliott, Kate-Ellen J; Scott, Jennifer L; Monsour, Michael; Nuwayhid, Fadi

    2015-01-01

    The purpose of the study is to describe from a relational perspective, partners' psychological adjustment, coping and support needs for advanced prostate cancer. A mixed methods design was adopted, employing triangulation of qualitative and quantitative data, to produce dyadic profiles of adjustment for six couples recruited from the urology clinics of local hospitals in Tasmania, Australia. Dyads completed a video-taped communication task, semi-structured interview and standardised self-report questionnaires. Themes identified were associated with the dyadic challenges of the disease experience (e.g. relationship intimacy, disease progression and carer burden). Couples with poor psychological adjustment profiles had both clinical and global locus of distress, treatment side-effects, carer burden and poor general health. Resilient couples demonstrated relationship closeness and adaptive cognitive and behavioural coping strategies. The themes informed the adaption of an effective program for couples coping with women's cancers (CanCOPE, to create a program for couples facing advanced prostate cancer (ProCOPE-Adv). Mixed method results inform the development of psychological therapy components for couples coping with advanced prostate cancer. The concomitance of co-morbid health problems may have implications for access and engagement for older adult populations in face-to-face intervention.

  15. Plasmonic reflectors and high-Q nano-cavities based on coupled metal-insulator-metal waveguides

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2012-03-01

    Full Text Available Based on the contra-directional coupling, a composite structure consisting of two coupled metal-insulator-metal (MIM waveguides is proposed to act as an attractive plasmonic reflector. By introducing a defect into one of the MIM waveguides, we show that such a composite structure can be operated as a plasmonic nanocavity with a high quality factor. Both symmetric and anti-symmetric cavity modes are supported in the plasmonic cavity, and their resonance frequencies can be tuned by controlling the defect width. The present structures could have a significant impact for potential applications such as surface plasmon mirrors, filters and solid-state cavity quantum electrodynamics.

  16. Dynamic analysis of large structures with uncertain parameters based on coupling component mode synthesis and perturbation method

    Directory of Open Access Journals (Sweden)

    D. Sarsri

    2016-03-01

    Full Text Available This paper presents a methodological approach to compute the stochastic eigenmodes of large FE models with parameter uncertainties based on coupling of second order perturbation method and component mode synthesis methods. Various component mode synthesis methods are used to optimally reduce the size of the model. The statistical first two moments of dynamic response of the reduced system are obtained by the second order perturbation method. Numerical results illustrating the accuracy and efficiency of the proposed coupled methodological procedures for large FE models with uncertain parameters are presented.

  17. S3EPY: a Sparky extension for determination of small scalar couplings from spin-state-selective excitation NMR experiments

    Czech Academy of Sciences Publication Activity Database

    Novák, P.; Žídek, L.; Motáčková, V.; Padrta, P.; Švenková, Alžběta; Nuzillard, J.-M.; Krásný, Libor; Sklenář, V.

    2010-01-01

    Roč. 46, č. 2 (2010), s. 191-197 ISSN 0925-2738 R&D Projects: GA ČR GA204/09/0583 Institutional research plan: CEZ:AV0Z50200510 Keywords : Software * Sparky * Residual dipolar couplings Subject RIV: EE - Microbiology, Virology Impact factor: 3.047, year: 2010

  18. Dispersion characteristics of electromagnetic waves in dipolar (m=±1) modes travelling along a magnetized plasma column

    International Nuclear Information System (INIS)

    Benova, E.; Ghanashev, I.; Zhelyazkov, I.

    1992-01-01

    The modelling of isotropic plasma columns sustained by travelling electromagnetic waves in the dipolar mode (angular dependence exp imφ, m=±1) shows that the m=±1 modes have identical dispersion characteristics. In the presence of an external static magnetic field, however, the modes behave rather differently. This observation arose in studying the axial structures of magnetized plasma columns surrounded by vacuum and produced by travelling electromagnetic waves in the dipolar modes. We examine the propagation of electromagnetic waves along a homogeneous cold plasma column of radius R and electron number density n immersed in an axial constant magnetic field. (author) 3 refs., 3 figs

  19. Dipolar flow theory of the universe in relation to astronomical observations and universe axis

    International Nuclear Information System (INIS)

    Mullick, U.P.

    1975-01-01

    An attempt has been made to establish Dipolar continuous flow theory of the universe through corroborations from astronomical observations of the positions of nebulae made earlier by astronomers. It is shown that the line through groups of nebulae in Nubecula Major in Southern Sky Region 5, passing through Earth points towards the near side pole A of the universe. Also the angles the plane parallel to universe polar plane x-x and passing through Earth, makes with the Milky Way disc is about 70 0 towards universe pole B, and about 110 0 towards nearside universe pole A. It is also shown that the two nebulae M 31 and M 33 and the groups of nebulae in Megallenic clouds, in Nebecula Major are between planes passing through universe equatorial axis y-y and plant Ysub(E)-Ysub(E) passing through Earth and parallel to universe equatorial plane Y-Y. Besides, the huge red star Betelgeux and the great Nebula in Orion in sky Region 9 are also between these two planes. These observations the author claims accord with his Dipolar Theory. (author)

  20. Effect of Dipolar Interactions on the Magnetization of Single-Molecule Magnets in a cubic lattice

    Science.gov (United States)

    Alcantara Ortigoza, Marisol

    2005-03-01

    Since the one-body tunnel picture of single-molecule magnets (SMM) is not always sufficient to explain the fine structure of experimental hysteresis loops, the effect of intermolecular dipolar interactions has been investigated on an ensemble of 100 3D-systems of 5X5X4 particles, each with spin S = 5, arranged in a cubic lattice. We have solved the Landau-Lifshitz-Gilbert equation for several values of the damping constant, the field sweep rate and the lattice constant. We find that the smaller the damping constant is, the stronger the maximum field needs to be to produce hysteresis. Furthermore, the shape of the hysteresis loops also depends on the damping constant. We also find that the system magnetizes and demagnetizes faster with decreasing sweep rates, resulting in smaller hysteresis loops. Variations of the lattice constant within realistic values (1.5nm and 2.5nm) show that the dipolar interaction plays an important role in magnetic hysteresis by controlling the relaxation process. Examination of temperature dependencies (0.1K and 0.7K) of the above will be presented and compared with recent experimental data on SMM.