WorldWideScience

Sample records for angular bipyridyl ligands

  1. Supramolecular architectures constructed using angular bipyridyl ligands

    CERN Document Server

    Barnett, S A

    2003-01-01

    This work details the synthesis and characterization of a series of coordination frameworks that are formed using bidentate angular N-donor ligands. Pyrimidine was reacted with metal(ll) nitrate salts. Reactions using Cd(NO sub 3) sub 2 receive particular focus and the analogous reactions using the linear ligand, pyrazine, were studied for comparison. In all cases, two-dimensional coordination networks were prepared. Structural diversity is observed for the Cd(ll) centres including metal-nitrate bridging. In contrast, first row transition metal nitrates form isostructural one-dimensional chains with only the bridging N-donor ligands generating polymeric propagation. The angular ligand, 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt), was reacted with Cd(NO sub 3) sub 2 and Zn(NO sub 3) sub 2. Whereas Zn(NO sub 3) sub 2 compounds exhibit solvent mediated polymorphism, a range of structures were obtained for the reactions with Cd(NO sub 3) sub 2 , including the first example of a doubly parallel interpenetrated 4.8 sup...

  2. Supramolecular architectures constructed using angular bipyridyl ligands

    International Nuclear Information System (INIS)

    This work details the synthesis and characterization of a series of coordination frameworks that are formed using bidentate angular N-donor ligands. Pyrimidine was reacted with metal(ll) nitrate salts. Reactions using Cd(NO3)2 receive particular focus and the analogous reactions using the linear ligand, pyrazine, were studied for comparison. In all cases, two-dimensional coordination networks were prepared. Structural diversity is observed for the Cd(ll) centres including metal-nitrate bridging. In contrast, first row transition metal nitrates form isostructural one-dimensional chains with only the bridging N-donor ligands generating polymeric propagation. The angular ligand, 2,4-bis(4-pyridyl)-1,3,5-triazine (dpt), was reacted with Cd(NO3)2 and Zn(NO3)2. Whereas Zn(NO3)2 compounds exhibit solvent mediated polymorphism, a range of structures were obtained for the reactions with Cd(NO3)2, including the first example of a doubly parallel interpenetrated 4.82 net. 4,7-phenanthroline, was reacted with various metal(ll) nitrates as well as cobalt(ll) and copper(ll) halides. The ability of 4,7-phenanthroline to act as both a N-donor ligand and a hydrogen bond acceptor has been discussed. Reactions of CuSCN with pyrimidine yield an unusual three-dimensional structure in which polymeric propagation is not a result of ligand bridging. The reaction of CuSCN with dpt yielded structural supramolecular isomers. (author)

  3. Establishing the Family of Diruthenium Water Oxidation Catalysts Based on the Bis(bipyridyl)pyrazolate Ligand System.

    Science.gov (United States)

    Neudeck, Sven; Maji, Somnath; López, Isidoro; Dechert, Sebastian; Benet-Buchholz, Jordi; Llobet, Antoni; Meyer, Franc

    2016-03-01

    A bis(bipyridyl)pyrazolate ((Me)bbp(-)) has recently been introduced as a rugged dinucleating, bis(tridentate) ligand for the formation of efficient diruthenium water oxidation catalysts (J. Am. Chem. Soc. 2014, 136, 24-27). Now, detailed protocols for the synthesis of a whole family of such dinuclear ruthenium complexes [{Ru(pyR(2))2}2(μ-(R1)bbp)(X,Y)](2+) based on the bis(bipyridyl)pyrazolate scaffold are reported. The isolation of a synthetic key intermediate allowed the straightforward introduction of different pyridines as axial ligands. Thereby, a set of complexes with different substituents at the pyrazolate backbone (R(1) = Br, H, Me), different pyridines as axial ligand (R(2) = H, NMe2, SO3), and different (non)bridging units in the in,in-position (X,Y = Cl, H2O, OAc) has been prepared and thoroughly characterized. Complexes of the type [{Ru(pyR(2))2}2(μ-(R1)bbp)(μ-OAc)](2+), with an exogenous acetato bridge, have been used as catalyst precursors in catalytic water oxidation experiments with a sacrificial oxidant. The effect of substitution on the pyrazole core of the (R1)bbp(-) ligand as well as on the pyridine ligands on both electrochemistry and catalytic activity has been systematically investigated. The catalyst stability, reflected by the turnover number, is crucially determined by the substituent at the pyrazolate ligand (R(1) = Me > H > Br). In contrast, the axial pyridine ligands modulate the rate of the catalytic process, expressed by the initial turnover frequency (R(2) = H > NMe2H(+)). PMID:26894408

  4. Intramolecular N-H···Cl hydrogen bonds in the outer coordination sphere of a bipyridyl bisurea-based ligand stabilize a tetrahedral FeLCl2 complex.

    Science.gov (United States)

    Gavette, Jesse V; Klug, Christina M; Zakharov, Lev N; Shores, Matthew P; Haley, Michael M; Johnson, Darren W

    2014-07-11

    A bipyridyl-based anion receptor is utilized as a ligand in a tetrahedral FeCl2 complex and demonstrates secondary coordination sphere influence through intramolecular hydrogen bonding to the chloride ligands as evidenced by X-ray crystallography.

  5. Crystal structures of titanocene 2,2 '-bipyridyl complexes. Singlet versus triplet state dependence on methyl substituents at the cyclopentadienyl ligands

    NARCIS (Netherlands)

    Gyepes, R; Witte, PT; Horacek, M; Cisarova, [No Value; Mach, K

    1998-01-01

    The X-ray diffraction analysis of titanocene-2,2'-bipyridyl complexes (C5H5)(2)Ti(bpy) (1), (C5HMe4)(2)Ti(bpy) (2) and (C5Me5)(2)Ti(bpy) (3) revealed that the bpy ligand is inclined to one of the cyclopentadienyl ligands in 1 and 2 whereas in 3 it lies in the plane bisecting the CE-Ti-CE angle of th

  6. Ruthenium Bis-diimine Complexes with a Chelating Thioether Ligand: Delineating 1,10-Phenanthrolinyl and 2,2'-Bipyridyl Ligand Substituent Effects

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rawashdeh, Nathir A. F.; Chatterjee, Sayandev; Krause, Jeanette A.; Connick, William B.

    2014-01-06

    A new series of ruthenium(II) bis-diimine complexes with a chelating thioether donor ligand has been prepared: Ru(diimine)2(dpte)2+ (diimine=1,10-phenanthroline (phen) (1); 5-CH3-phen (2), 5-Cl-phen (3); 5-Br-phen (4); 5-NO2-phen (5); 3,4,7,8-tetramethyl-phen (6); 4,7-diphenyl-phen (7); 5,5'-dimethyl-2,2'-bipyridine (8); 4,4'-di-tert-butyl-2,2'-bipyridine (9)). Crystal structures of 2, 5, 7 and 9 show that the complexes form 2 of the 12 possible conformational/configurational isomers, adopting compact C2-symmetric structures with short intramolecular transannular interactions between the diimine ligands and dpte phenyl groups; crystals of 2 and 5 contain non-statistical distributions of geometric isomers. In keeping with the π-acidity of the dpte, the Ru(III/II) couple, E°'(Ru3+/2+), occurs at relatively high potentials (1.4-1.7 V vs Ag/AgCl), and the lowest spin-allowed MLCT absorption band occurs near 400 nm. Surprisingly, the complexes also exhibit fluid-solution luminescence originating from a lowest MLCT excited state with lifetimes in the 140-750 ns time range; in acetonitrile, compound 8 undergoes photo-induced solvolysis. Variations in the MLCT energies and redox potentials are quantitatively described using a summative Hammett parameter (σT), as well as using Lever's electrochemical parameters (EL). Recommended parameterizations for 2,2'-bipyridyl and 1,10-phenanthrolinyl ligands were derived from analysis of correlations based on 199 measurements of E°'(Ru3+/2+) for 99 homo- and heteroleptic ruthenium(II) tris-diimine complexes. Variations in E°'(Ru3+/2+) due to substituents at the 4- and 4'-positions of bipyridyl ligands and 4- and 7-positions of phenanthrolinyl ligands are significantly more strongly correlated with σp+ than either σm or σp. Substituents at the 5- and 6-positions of phenanthrolinyl ligands are best described by σm and have effects comparable to those of substituents at the 3

  7. Synthesis and Crystal Structure of a Co(II) Coordination Polymer Derived from a Flexible Bipyridyl Derivative Ligand

    Institute of Scientific and Technical Information of China (English)

    GONG Ya-Qiong; WANG Rui-Hu; WU Ben-Lai; LOU Ben-Yong; HAN Lei; HONG Mao-Chun

    2005-01-01

    The self-assembly of a flexible bipyridyl ligand 2,2'-bis(4-pyridylmethyle- neoxy)-1,1'-biphenylene (4,4'-bpp) with cobalt(II) center gave rise to a one-dimensional chain complex [Co(μ-4,4'-bpp)2(SCN)2(H2O]n 1 which has been characterized by single-crystal X-ray diffraction. The polymer crystallizes in monoclinic, space group C2/c with unit cell parameters: a = 13.1888(13), b = 24.230(2), c = 15.4218(17) (A), β = 93.291(6)°, V = 4920.1(8) (A)3, Z = 4, C50H42CoN6O5S2, Mr = 929.95, Dc = 1.255 g/cm3, F(000) = 1932 and μ(MoKα) = 0.484 mm-1. The final R and wR are 0.0691 and 0.1670 for 3746 observed reflections with I > 2σ(I). 1 possesses an infinite 1-D polymeric chain structure consisting of the repeated basic square units Co2(μ-4,4'-bpp)2, where the Co(II) center acts as the joint of the square ring. The Co(II) center is coordinated in a slightly distorted octahedral geometry with four nitrogen atoms from four different 4,4'-bpp ligands in the equatorial plane and two trans thiocyanate ligands occupying the axial positions, preventing the formation of an extended framework.

  8. Synthesis and properties of new mononuclear Ru(ii)-based photocatalysts containing 4,4'-diphenyl-2,2'-bipyridyl ligands.

    Science.gov (United States)

    Coe, Benjamin J; Sánchez, Sergio

    2016-03-15

    The synthesis and characterisation of a series of eleven new 4,4'-diphenyl-2,2'-bipyridyl derivatives (N^N) with varying 4- or 3,5-substituents on the phenyl rings are reported. The molecular structures of two of these compounds, 4,4'-bis(3,5-diheptyloxyphenyl)-2,2'-bipyridyl and 4,4'-bis(3,5-di-4,4,5,5,5-pentafluoropentyloxyphenyl)-2,2'-bipyridyl are confirmed by X-ray crystallography. Fourteen neutral complexes trans-Ru(II)Cl2(N^N)(CO)2 are prepared by reacting the new proligands and three known ones with the polymeric precursor [Ru(II)Cl2(CO)2]n, and their optical and electrochemical properties are studied. Density functional theory (DFT) and time-dependent DFT calculations have been carried out on selected complexes in order to rationalise their electronic structures and absorption properties. The low energy electronic absorption bands have metal-to-ligand charge-transfer and ligand-to-ligand charge-transfer (LLCT) character, but these dominate only in the 4-substituted species. In the 3,5-disubstituted ones, intraligand charge-transfer (ILCT) within the bpy ligands becomes more important. The complexes show only irreversible reductive electrochemistry and no signs of polymerisation. The photocatalytic oxidation behaviour of selected trans-Ru(II)Cl2(N^N)(CO)2 complexes and their mono-aquo derivatives [Ru(II)(H2O)(CO)2Cl(N^N)](+) with 4-methoxybenzyl alcohol is studied. Turnover numbers of up to ca. 130 are achieved when using [Ru(II)(bpy)3](2+) (bpy = 2,2'-bipyridyl) as photosensitizer and [Co(III)(NH3)5Cl](2+) as a sacrificial oxidant. PMID:26890960

  9. Spectroscopy and quantum-chemical calculations of nitro-bis-bipyridyl complexes of ruthenium(II) with 4-substituted pyridine ligands

    Science.gov (United States)

    Reshetova, K. I.; Krauklis, I. V.; Litke, S. V.; Ershov, A. Yu.; Chizhov, Yu. V.

    2016-04-01

    The luminescence, absorption, and luminescence excitation spectra of complexes cis-[Ru(bpy)2(L)(NO2)]+ [bpy = 2,2'-bipyridyl, L = pyridine, 4-aminopyridine, 4-dimethylaminopyridine, 4-picoline, isonicotinamide, or 4,4'-bipyridyl] in alcoholic (4 : 1 EtOH-MeOH) solutions are studied at 77 K. A linear correlation is established between the energy of the lowest electronically excited metal-toligand charge transfer state d π(Ru) → π*(bpy) of the complexes and the pKa parameter of the free 4-substituted pyridines used as ligands L. The B3LYP/[6-31G(d)+LanL2DZ(Ru)] hybrid density functional method is used to optimize the geometry of complexes and calculate their electronic structure and the charge distribution on the atoms of the nearest environment of ruthenium(II) ions. It is shown that there exists a mutually unambiguous correspondence between the charge on the nitrogen atom of ligands L coordinated in the complex and the pK a parameter of ligands. The calculated energies of the electronically excited metal-to-ligand charge transfer states of complexes linearly (correlation coefficient 0.99) depend on the charge on the nitrogen atom of ligands L, which completely agrees with the experimental data.

  10. Mixed-ligand binuclear copper(II) complex of 5-methylsalicylaldehyde and 2,2'-bipyridyl: Synthesis, crystal structure, DNA binding and nuclease activity

    Indian Academy of Sciences (India)

    Perumal Gurumoorthy; Jayaram Ravichandran; Aziz Kalilur Rahiman

    2014-05-01

    A new mixed-ligand binuclear copper(II) complex [Cu(MS)(bpy)]2.(ClO4)2, built of 5-methylsalicylaldehyde and 2,2'-bipyridyl has been synthesized and characterized by using elemental analysis, IR and UV-Vis spectroscopy. Crystal structure of the complex shows that copper(II) ion lies in a square pyramidal coordination environment. The structure consists of two symmetrical half units in which the copper(II) ion of one half unit connected with the phenolate oxygen atom of other half unit along with one perchlorate anion in the crystal lattice as free molecule. Presence of uncoordinated perchlorate anion was also confirmed by IR spectroscopy. Absorption spectroscopy exhibits d-d transition at 628 nm, which further supports the square pyramidal geometry around the copper(II) ions. EPR spectrum of the copper(II) complex at room temperature shows a broad signal without any splitting pattern at ∥ = 2.26, ⊥ = 2.03 and the magnetic moment (eff = 1.31 BM) obtained at room temperature indicate an antiferromagnetic interaction between the two copper(II) ions through phenoxide-bridge. Binding studies reveal that the complex possesses good binding propensity (b = 5.2 ± 1.7 × 104 M-1) and bind to nitrogenous bases of DNA through intercalation. Nuclease activity of the complex with pBR322 DNA shows that the effect of hydrolytic cleavage is dose-dependent and the oxidative cleavage indicates the involvement of hydroxyl radical and singlet-oxygen as reactive oxygen species.

  11. Comparison of bipyridyl, maltol and kojic acid action as organic vanadium ligands on activity of galactosyltransferase (EC 2.4.1.38), some physiological parameters and ultrastructure of Golgi complexes in rat hepatocytes.

    Science.gov (United States)

    Dabros, Wojciech; Kordowiak, Anna

    2007-01-01

    The biochemical activity and morphology of control and streptozotocin-diabetic rat liver Golgi complexes were previously investigated by us under influence of some vanadium [V(IV)] compounds. The effectiveness of these derivatives depends on the kind of complexing ligands. This paper presents the investigation of the effect of bipyridyl, the ligand of a new vanadium compound, tested by us with maltol and kojic acid (two ligands studied by the present and other authors). The three ligands alone action was tested under the same experimental conditions as in the case of whole compounds with vanadium and applied to liver Golgi complexes of control rats. A preliminary study for maltol and kojic acid had been previously carried out by us parallel with tests of whole vanadium complexes, but valuable differences in biological action found in our condition of experiments suggested the extension of studies to include the two above-mentioned ligands and to compare the effects of the three investigated ligands. The supplementary part of the experiment focused mainly on the ultrastructure of Golgi complexes in hepatocytes. Four groups of animals were used: C - control rats, C + M (maltol), C + (ka)2 (kojic acid) and C + (bpy)2 (bipyridyl). The control rats received 0.09M NaCl as drinking liquid; all the other animals were given 3.6 mmol/L of appropriate ligand solution in 0.09M NaCl during 7 days. All the animals survived the experiments. Only in group C + (bpy)2 did the authors observe statistically significant differences as compared with the controls (group C). The differences were detected in physiological studies and manifested as body weight decreased by approximately 20% during the experiment, lower liquid (pfood (pvanadium compounds were employed in our earlier experiments. As it follows, the ligands alone were demonstrated to be much more toxic to morphology of control liver Golgi apparatus as compared to complex compounds, which showed the ability of the former to

  12. Comparison of bipyridyl, maltol and kojic acid action as organic vanadium ligands on activity of galactosyltransferase (EC 2.4.1.38, some physiological parameters and ultrastructure of Golgi complexes in rat hepatocytes.

    Directory of Open Access Journals (Sweden)

    Wojciech Dabros

    2007-10-01

    Full Text Available The biochemical activity and morphology of control and streptozotocin-diabetic rat liver Golgi complexes were previously investigated by us under influence of some vanadium [V(IV] compounds. The effectiveness of these derivatives depends on the kind of complexing ligands. This paper presents the investigation of the effect of bipyridyl, the ligand of a new vanadium compound, tested by us with maltol and kojic acid (two ligands studied by the present and other authors. The three ligands alone action was tested under the same experimental conditions as in the case of whole compounds with vanadium and applied to liver Golgi complexes of control rats. A preliminary study for maltol and kojic acid had been previously carried out by us parallel with tests of whole vanadium complexes, but valuable differences in biological action found in our condition of experiments suggested the extension of studies to include the two above-mentioned ligands and to compare the effects of the three investigated ligands. The supplementary part of the experiment focused mainly on the ultrastructure of Golgi complexes in hepatocytes. Four groups of animals were used: C - control rats, C + M (maltol, C + (ka2 (kojic acid and C + (bpy2 (bipyridyl. The control rats received 0.09M NaCl as drinking liquid; all the other animals were given 3.6 mmol/L of appropriate ligand solution in 0.09M NaCl during 7 days. All the animals survived the experiments. Only in group C + (bpy2 did the authors observe statistically significant differences as compared with the controls (group C. The differences were detected in physiological studies and manifested as body weight decreased by approximately 20% during the experiment, lower liquid (p<0.001 and food (p<0.01 intake and increase of free blood sugar level (p<0.01. The yield of Golgi membrane isolation decreased in this group (p<0.01. The main investigated biochemical parameter, i.e. the activity of liver Golgi marker enzyme

  13. Synthesis, Photophysical and Electrochemical Properties of a Mixed Bipyridyl-Phenanthrolyl Ligand Ru(II Heteroleptic Complex Having trans-2-Methyl-2-butenoic Acid Functionalities

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeloye

    2011-09-01

    Full Text Available In this work, two ligands: 4-(trans-2-Methyl-2-butenoic acid-2,2'-bipyridine (L1 and 5-(trans-2-methyl-2-butenoic acid-1,10-phenanthroline (L2, with the corresponding mixed-ligand heteroleptic Ru(II complex were synthesized and characterized by FT-IR, 1H-, 13C-NMR spectroscopy and elemental analysis. The influence of the mixed functionalized polypyridyl ruthenium(II complex on the photophysical and electrochemical properties were investigated and compared to individual single-ligand homoleptic complexes. Interestingly, the mixed-ligand complex formulated as [RuL1L2(NCS2] exhibits broad and intense metal-to-ligand charge transfer (MLCT absorption with a high molar extinction coefficient (λmax = 514 nm, ε = 69,700 M−1 cm−1, better than those of individual single-ligand complexes, [Ru(L12(NCS2] and [Ru(L22(NCS2], and a strong photoluminescence intensity ratio in the red region at λem = 686 nm. The electrochemical properties of the complex indicated that the redox processes are ligand-based.

  14. Kinetics and mechanism of the ligand substitution reaction of di--hydroxobis(bipyridyl)dipalladium(II) ion with diethyldithiocarbamate anion in aqueous solution

    Indian Academy of Sciences (India)

    Subhasis Mallick; Biplab K Bera; Subala Mondal; Parnajyoti Karmakar; Arup Mandal; Alak K Ghosh

    2011-05-01

    The kinetics of the interaction between diethyldithiocarbamate (Et2DTC) and the title complex has been studied spectrophotometrically in aqueous medium as a function of nucleophile concentration, temperature and pH at constant ionic strength. The reaction is a two-step process in which the first step is liganddependent, but the second step is ligand-independent and is assigned to ring closure. The rate and activation parameters, conductivity studies and IR data were used to deduce a plausible mechanism.

  15. Synthesis, spectroscopic studies, thermal analyses, biological activity of tridentate coordinated transition metal complexes of bi(pyridyl-2-ylmethyl)amine]ligand

    Science.gov (United States)

    Abd El-Halim, Hanan F.; Mohamed, Gehad G.

    2016-01-01

    A new tridentate acyclic pincer ligand, [bi(pyridin-2-methyl)amine] (bpma, HL), was synthesized and reacted to form complexes with copper(II), nickel(II), iron(II), cobalt(II) and zinc(II) ions. Both the ligand and its complexes were characterized using elemental analysis, molar conductance, infrared, 1H-NMR-spectroscopy, mass and thermal analyses. According to the spectroscopic data, all of the complexes share the same coordination environment around the metal atoms, consisting two nitrogen-pyridine entities, one nitrogen-methylamine entity, one/two water molecules and/or one/two chloride or bromide ions. Complexes also showed molar conductivity according to the presence of two halide anions outer the coordination sphere except Co(II) and Zn(II) complexes are non electrolytes. Analysis indicates that the metal ions have trigonal bipyramidal structure. Cu(II), Ni(II), Fe(II), Co(II), and Zn(II) metal complexes were screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus (G+) and Escherichia coli, and Pseudomonas aeruginosa (G-) bacteria. They showed remarkable antimicrobial activity.

  16. Chelating bis-N-heterocyclic carbene complexes of iron(ii) containing bipyridyl ligands as catalyst precursors for oxidation of alcohols.

    Science.gov (United States)

    Pinto, Mara F; Cardoso, Bernardo de P; Barroso, Sónia; Martins, Ana M; Royo, Beatriz

    2016-09-14

    Chelating bis-N-heterocyclic carbene (bis-NHC) complexes of iron(ii) containing pyridyl ligands have been prepared by the reaction of [FeCl2L] [L = bipy (1), phen (2)] with [LiN(SiMe3)2] and a bis(imidazolium) salt. The [Fe(bis-NHC)L(I)2] complexes were active pre-catalysts in the oxidation of 1-phenylethanol with tert-butyl hydroperoxide in neat conditions, affording a quantitative yield of acetophenone in 4.5 h. The catalyst could be reused up to six cycles giving a turnover number (TON) of 1500. Various secondary alcohols, both aromatic and aliphatic were selectivity oxidised to the corresponding ketones in excellent yields. Compound 1 is stable in acetonitrile solution for ca. 4 h, although after 16 h, it evolves to a mixture of [Fe(bis-NHC)(bipy)2]I2 (3), [Fe(bipy)3](2+) and bis-imidazolium salt. The molecular structure of 3 has been determined by X-ray diffraction studies. PMID:27506414

  17. Structures of nitrato-(2-hydroxybenzaldehydo) (2,2′-bipyridyl)copper and nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2′-bipyridyl)copper

    International Nuclear Information System (INIS)

    Nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2′-bipyridyl)copper (I) and nitrato-(2-hydroxybenzaldehydo)(2,2′-bipyridyl)copper (II) were synthesized and characterized by X-ray diffraction. The coordination polyhedron of the central copper atom in complex I can be described as a distorted tetragonal pyramid whose base is formed by the phenol and carbonyl oxygen atoms of the monodeprotonated 2-hydroxy-5nitrobenzaldehyde molecule and the nitrogen atoms of the 2,2′-bipyridyl ligand and whose apex is occupied by the oxygen atom of the nitrato group. In the crystal structure, complexes I are linked by the acido ligands and the NO2 groups of the aldehyde molecule into infinite chains. In complex II, the central copper atom is coordinated by 2-hydroxybenzaldehyde, 2,2′-bipyridyl, and the nitrato group, resulting in the formation of centrosymmetric dimers. The coordination polyhedron of the central copper atom can be described as a bipyramid (4 + 1 + 1) with the same base as in complex I. The axial vertices of the bipyramid are occupied by the oxygen atom of the nitrato group and the bridging phenol oxygen atom of the adjacent complex related to the initial complex by a center of symmetry. In the crystal structure, complexes II are hydrogen bonded into infinite chains.

  18. Synthesis of Two Novel Rhenium(I) Bipyridyl Photosensitive Dyes

    Institute of Scientific and Technical Information of China (English)

    Shi Guo SUN; Xiao Jun PENG; Ming Wen FAN; Yong Qian XU; Lei SHI; Li Cheng SUN

    2004-01-01

    Two novel rhenium(I) 2, 2'-bipyridyl complexes, [(4,4'-di-COOEt-bipy) Re(CO)3 (NCCH3)PF6] and [(4,4'-di-COOEt-bipy) Re (CO)3 (NCS)], a model complex [(4,4'-di- COOEt- bipy) Re (CO)3 (pyridine)PF6], were synthesized.Their ground state electronic spectra and emission spectra were measured in acetonitrile.The MLCT absorption maximum of the complex exhibited a considerable red shift as the ligand changed from pyridine to CNCH3, or SCN.

  19. Assembly, characterization, and electrochemical properties of immobilized metal bipyridyl complexes on silicon(111) surfaces.

    Science.gov (United States)

    Lattimer, Judith R C; Blakemore, James D; Sattler, Wesley; Gul, Sheraz; Chatterjee, Ruchira; Yachandra, Vittal K; Yano, Junko; Brunschwig, Bruce S; Lewis, Nathan S; Gray, Harry B

    2014-10-28

    Silicon(111) surfaces have been functionalized with mixed monolayers consisting of submonolayer coverages of immobilized 4-vinyl-2,2'-bipyridyl (1, vbpy) moieties, with the remaining atop sites of the silicon surface passivated by methyl groups. As the immobilized bipyridyl ligands bind transition metal ions, metal complexes can be assembled on the silicon surface. X-ray photoelectron spectroscopy (XPS) demonstrates that bipyridyl complexes of [Cp*Rh], [Cp*Ir], and [Ru(acac)2] were formed on the surface (Cp* is pentamethylcyclopentadienyl, acac is acetylacetonate). For the surface prepared with Ir, X-ray absorption spectroscopy at the Ir LIII edge showed an edge energy as well as post-edge features that were essentially identical with those observed on a powder sample of [Cp*Ir(bpy)Cl]Cl (bpy is 2,2'-bipyridyl). Charge-carrier lifetime measurements confirmed that the silicon surfaces retain their highly favorable photoelectronic properties upon assembly of the metal complexes. Electrochemical data for surfaces prepared on highly doped, n-type Si(111) electrodes showed that the assembled molecular complexes were redox active. However the stability of the molecular complexes on the surfaces was limited to several cycles of voltammetry.

  20. Synthesis, Spectroscopic, and Anticancerous Properties of Mixed Ligand Palladium(II) and Silver(I) Complexes with 4,6-Diamino-5-hydroxy-2-mercaptopyrimidine and 2,2′-Bipyridyl

    Science.gov (United States)

    Mostafa, Sahar I.; Badria, Farid A.

    2008-01-01

    Synthesis of two new water-soluble mixed ligand [Pd(bpy)(dahmp)]Cl and [Ag(bpy)(Hdahmp)]NO3 complexes (dahmp and Hdahmp are the deprotonated monoanion and the protonated neutral 4,6-diamino-5-hydroxy-2-mercaptopyrimidine, resp.) is reported. The composition of the reported complexes was discussed on the bases of IR, 1H NMR, and mass spectra, as well as conductivity and thermal measurements. The reported complexes display a significant anticancer activity against Ehrlich ascites tumor cells (EACs). The higher activity of these complexes with their higher conductivity values corresponds to their complete ionization in aqueous solution. PMID:18414586

  1. Dissociation and Dioxygen Formation in Hydroxide Solutions of Tris (2,2- bipyridyl) Iron (III) and Tris (1,10-phenanthroline) Iron (III)

    DEFF Research Database (Denmark)

    Nord, G.; Pedersen, B.; Bjergbakke, Erling

    1983-01-01

    to dioxygen. No O2 is produced when dissociation of tns(2,2’-bipyridyl)iron(III) is suppressed by addition of excess ligand; the dependence of the O2 yield on the degree of dissociation of this complex can be reproduced by using the rate constants for the parallel catalyzed and uncatalyzed decay of the first...

  2. Facile synthesis of one-dimensional organometallic-organic hybrid polymers based on a diphosphorus complex and flexible bipyridyl linkers.

    Science.gov (United States)

    Elsayed Moussa, M; Attenberger, B; Peresypkina, E V; Fleischmann, M; Balázs, G; Scheer, M

    2016-08-21

    The selective synthesis of a series of new "ladderlike" one-dimensional organometallic-organic hybrid polymers is shown. The polymers are obtained from the reaction of the diphosphorus ligand complex [Cp2Mo2(CO)4(η(2)-P2)] with the copper salt [Cu(CH3CN)4]BF4 in the presence of flexible organic bipyridyl linkers in high selectivity. This unique behaviour is supported by DFT calculations.

  3. A High Molar Extinction Coefficient Mono-Anthracenyl Bipyridyl Heteroleptic Ruthenium(II Complex: Synthesis, Photophysical and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    2011-06-01

    Full Text Available In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs, cis-dithiocyanato-4-(2,3-dimethylacrylic acid-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic-2,2'-bipyridyl ruthenium(II complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT band absorption with higher molar extinction coefficient (λmax = 518 nm, e = 44900 M−1cm−1, and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended π-conjugation but are reduced by molecular aggregation in the molecules.

  4. Tris(2,2′-bipyridyl-κ2N,N′copper(II sulfate 7.5-hydrate

    Directory of Open Access Journals (Sweden)

    Wei Huang

    2009-02-01

    Full Text Available The title compound, [Cu(C10H8N23]SO4·7.5H2O, is a six-coordinate copper(II complex with a slightly elongated octahedral coordination geometry. The pyridyl rings of the three bipyridyl ligands are not coplanar, making dihedral angels of 9.5 (5, 5.2 (4 and 5.8 (5°. In the crystal, several O—H...O and C—H...O hydrogen-bonding interactions are observed due to the existance of a large number of water molecules and the sulfate dianions.

  5. Mixed ligand coordination polymers with flexible bis-imidazole linker and angular sulfonyldibenzoate: Crystal structure, photoluminescence and photocatalytic activity

    International Nuclear Information System (INIS)

    Four ternary coordination polymers (CPs) namely, ([Ni(SDB)(BITMB)(H2O)]·H2O)n (CP1), ([Cd(SDB)(BITMB) (H2O)]·(THF)(H2O))n (CP2), ([Zn2(SDB)2(BITMB)]·(THF)2)n (CP3) and ([Co2(SDB)2(BITMB)]·(Dioxane)3)n (CP4) composed of angular dicarboxylate SDB (4,4'-sulfonyldibenzoate) and N-donor BITMB (1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethyl benzene) have been synthesized by solvothermal reactions and characterized by single crystal X-ray diffraction and other physico-chemical techniques. CP1 possesses one-dimensional ribbon type metal–organic motifs glued together by H-bonds and π⋯π interactions, whereas CP2–CP4, exhibit non-interpenetrated sql networks supported by weak supramolecular interactions. Structural diversity of these CPs can be attributed to the coordination geometry adopted by the metal nodes, versatile coordination modes of SDB and conformational flexibility of BITMB. Solid state luminescence properties of CP1–CP4 were explored. Photocatalytic performance of all CPs for the decomposition of metanil yellow by dilute hydrogen peroxide in the presence of visible light was also investigated. 25–83% dye removal from aqueous solutions in the presence of CP1–CP4 was observed. - Graphical abstract: Four new ternary transition metal CPs have been hydrothermally prepared and their structural aspects as well as photocatalytic activity for decolourization of metanil yellow (MY) dye have been investigated. - Highlights: • Four ternary coordination polymers containing Ni, Cd, Zn and Co center are prepared. • Crystal structure and thermal stability of all four CPs has been described. • PL and diffuse reflectance spectra of synthesized CPs have also been examined. • Band gap values suggest semiconducting behavior of prepared CPs. • Photocatalytic activity of CPs for oxidative degradation of metanil yellow is studied

  6. Mixed ligand coordination polymers with flexible bis-imidazole linker and angular sulfonyldibenzoate: Crystal structure, photoluminescence and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Bisht, Kamal Kumar; Rachuri, Yadagiri [Analytical Discipline and Centralized Instrument Facility, CSIR—Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar-364 002, Gujarat (India); Academy of Scientific and Innovative Research (AcSIR), CSIR—Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar-364 002, Gujarat (India); Parmar, Bhavesh [Analytical Discipline and Centralized Instrument Facility, CSIR—Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar-364 002, Gujarat (India); Suresh, Eringathodi, E-mail: esuresh@csmcri.org [Analytical Discipline and Centralized Instrument Facility, CSIR—Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar-364 002, Gujarat (India); Academy of Scientific and Innovative Research (AcSIR), CSIR—Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research, G. B. Marg, Bhavnagar-364 002, Gujarat (India)

    2014-05-01

    Four ternary coordination polymers (CPs) namely, ([Ni(SDB)(BITMB)(H{sub 2}O)]·H{sub 2}O){sub n} (CP1), ([Cd(SDB)(BITMB) (H{sub 2}O)]·(THF)(H{sub 2}O)){sub n} (CP2), ([Zn{sub 2}(SDB){sub 2}(BITMB)]·(THF){sub 2}){sub n} (CP3) and ([Co{sub 2}(SDB){sub 2}(BITMB)]·(Dioxane){sub 3}){sub n} (CP4) composed of angular dicarboxylate SDB (4,4'-sulfonyldibenzoate) and N-donor BITMB (1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethyl benzene) have been synthesized by solvothermal reactions and characterized by single crystal X-ray diffraction and other physico-chemical techniques. CP1 possesses one-dimensional ribbon type metal–organic motifs glued together by H-bonds and π⋯π interactions, whereas CP2–CP4, exhibit non-interpenetrated sql networks supported by weak supramolecular interactions. Structural diversity of these CPs can be attributed to the coordination geometry adopted by the metal nodes, versatile coordination modes of SDB and conformational flexibility of BITMB. Solid state luminescence properties of CP1–CP4 were explored. Photocatalytic performance of all CPs for the decomposition of metanil yellow by dilute hydrogen peroxide in the presence of visible light was also investigated. 25–83% dye removal from aqueous solutions in the presence of CP1–CP4 was observed. - Graphical abstract: Four new ternary transition metal CPs have been hydrothermally prepared and their structural aspects as well as photocatalytic activity for decolourization of metanil yellow (MY) dye have been investigated. - Highlights: • Four ternary coordination polymers containing Ni, Cd, Zn and Co center are prepared. • Crystal structure and thermal stability of all four CPs has been described. • PL and diffuse reflectance spectra of synthesized CPs have also been examined. • Band gap values suggest semiconducting behavior of prepared CPs. • Photocatalytic activity of CPs for oxidative degradation of metanil yellow is studied.

  7. Inherent helicity in an extended tris-bipyridyl molecular cage

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, D.; Lindoy, L.; Meehan, G.; Turner, P. (University of Sydney)

    2010-11-16

    A new molecular cage incorporating three bipyridyl units has been synthesised by a conventional multi-step procedure as well as, much more efficiently, by a Ni(II) template procedure; an X-ray structure of the nickel complex shows that it adopts an exo configuration of each of the bridgehead nitrogen lone pairs, the central metal ion acts to promote a triple helical twist that extends {approx}22 {angstrom} along the axial length of the molecule.

  8. Visualization of Metal-to-Ligand and Ligand-to-Ligand Charge Transfer in Metal-Ligand Complexes

    Institute of Scientific and Technical Information of China (English)

    Yong Ding; Jian-xiu Guo; Xiang-si Wang; Sha-sha Liu; Feng-cai Ma

    2009-01-01

    Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer (MLCT) in ruthenium(Ⅱ) ammine complex. The atomic resolved density of state shows that there is density of Ru on the HOMOs. All the density is localized on the ammine, which reveals that the excited electrons in the Ru complex are delocalized over the ammine ligand. The charge difference density shows that all the holes are localized on the Ru and the electrons on the ammine. The localization explains the MLCT on excitation. The transition density matrix shows that there is electron-hole coherence between Ru and ammine. These methods are also used to examine the MLCT in Os(bpy)(p0p)Cl ("Osp0p"; bpy=2,2'-bipyridyl; p0p=4,4'-bipyridyl) and the ligand-to-ligand charge transfer (LLCT) in Alq3. The calculated results show that these methods are powerful to examine MLCT and LLCT in the metal-ligand system.

  9. Tris(2,2'-bipyridyl) Ruthenium(Ⅱ) Doped Silica Film Modified Indium Tin Oxide Electrode and Its Electrochemiluminescent Properties

    Institute of Scientific and Technical Information of China (English)

    WEI Hui; DU Yan; KANG Jian-Zhen; XU Guo-Bao; WANG Er-Kang

    2007-01-01

    An approach was reported to synthesize silica hybridized ruthenium bipyridyl complex through amidation reaction by covalent attachment of bis(bipyridyl)-4,4'-dicarboxy-2,2'-bipyridyl-ruthenium to (3-aminopropyl)-triethoxysilane.The hybrid complex then was gelatinized through acid catalytic hydrolysis method and a sol-gel modified indium tin oxide electrode was prepared via spin coating technique. As prepared indium tin oxide electrode possesses good stability therein with excellent electrochemiluminescence behavior.

  10. Angular Cheilitis

    Science.gov (United States)

    ... A This image displays a frequent location for candida infection (angular cheilitis), the corners of the mouth. Overview ... infection, those affected may also have thrush (oral candidiasis). The areas are generally slightly painful. The condition ...

  11. Angular Momentum

    Science.gov (United States)

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

    The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

  12. Synthesis, spectroscopic, electrochemical and luminescence studies of ruthenium (II) polypyridyls containing multifunctionalized 1,2,4-triazole as co-ligand

    Indian Academy of Sciences (India)

    L Mishra; A K Yadaw

    2000-08-01

    Ruthenium (II) 2,2 -bipyridyl and 1,10-phenanthroline complexes with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (LH2) as co-ligand were synthesised and characterized by elemental analysis, IR, UV/Vis, 1H NMR spectra and FAB-mass data. The electrochemical and luminescent properties of the complexes were also studied.

  13. Catalytic C-H imidation of aromatic cores of functional molecules: ligand-accelerated Cu catalysis and application to materials- and biology-oriented aromatics.

    Science.gov (United States)

    Kawakami, Takahiro; Murakami, Kei; Itami, Kenichiro

    2015-02-25

    Versatile imidation of aromatic C-H bonds was accomplished. In the presence of copper bromide and 6,6'-dimethyl-2,2'-bipyridyl, a range of aromatics, such as polycyclic aromatic hydrocarbons, aromatic bowls, porphyrins, heteroaromatics, and natural products, can be imidated by N-fluorobenzenesulfonimide. A dramatic ligand-accelerated copper catalysis and an interesting kinetic profile were uncovered.

  14. Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: Syntheses, crystal structures, thermal analysis and luminescence study

    Indian Academy of Sciences (India)

    Muhammad Idiris Saleh; Min Yee Choo; Tai Wei Chan; Mohd R Razali

    2015-12-01

    The ternary complexes of Sm(III) with dibenzoylmethane (dbm) were synthesized by introducing 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dmphen), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen), 4,7-diphenyl-1,10-phenanthroline (dpphen), 2,2-bipyridyl (bpy), 4,4’-dimethyl-2,2-bipyridyl (4,4-dmbpy), 5,5’-dimethyl-2,2-bipyridyl (5,5-dmbpy) and 4,4’-di-tert-butyl-2,2-bipyridyl (4,4-dtbbpy) as a second ligand. The complexes were isolated and characterized by elemental analysis (CHN), thermogravimetric analysis (TGA), IR spectroscopy, luminescence spectroscopy and single crystal X-ray diffraction. Structural study shows that in all complexes Sm(III) is in square antiprism geometry. All complexes emit strong luminescence under ultraviolet excitation. The strongest emission is at 643 nm which can be assigned for 4G5/2 to 6H9/2 transition, equivalent to energy of 15550 cm−1. The addition of the second ligand has increased the emission intensity of the complexes while the transition is maintained.

  15. Effect of methylene spacers on the spectral, electrochemical, and structural properties of bis(4,4'-disubstituted-2,2'-bipyridyl) ruthenium(II) dye analogues.

    Science.gov (United States)

    Lense, Sheri; Hardcastle, Kenneth I; MacBeth, Cora E

    2009-09-28

    Two new ruthenium complexes, [Ru(L1OMe)2(NCS)2] and [Ru(L2OMe)2(NCS)2] (where L1OMe = 2,2'-bipyridine-4,4'-di(methyl ethanoate) and L2OMe = 2,2'-bipyridine-4,4'-di(methyl propionate)), have been synthesized and characterized using spectroscopic and electrochemical techniques. The [Ru(L2OMe)2(NCS)2] complex has also been characterized by X-ray diffraction studies and reveals a distorted octahedral coordination geometry about the ruthenium center. Cyclic voltammetry studies of both complexes exhibit quasi-reversible Ru(II/III) couples and a number of ligand reduction events. The complex with one methylene spacer between the bipyridyl ligand and the methyl ester functional group, [Ru(L1OMe)2(NCS)2], was particularly unstable under reducing conditions. The properties of these complexes are compared with the ethyl ester analogue of the N3 photosensitizer [Ru(L0OEt)2(NCS)2].

  16. Ruthenium(II)- bipyridyl with extended -system: Improved thermo-stable sensitizer for efficient and long-term durable dye sensitized solar cells

    Indian Academy of Sciences (India)

    M Chandrasekharam; G Rajkumar; Ch Srinivasa Rao; T Suresh; P Y Reddy; Y Soujanya

    2011-09-01

    A new extended thermo-stable high molar extinction coefficient bipyridyl ruthenium(II) complex "cis-Ru(4,4'-bis(3,5-di-tert-butylphenyl)-2,2'-bipyridine)(Ln)(NCS)2 H101", where Ln = 4,4'-dicarboxylic acid-2,2'-bipyridine; was synthesized and characterized by 1H-NMR, FT-IR and ESI-MASS spectroscopes. The H101 sensitized solar cell constructed with an active area of 0.54 cm2 in combination with an ionic liquid electrolyte exhibited broader photocurrent action spectrum with solar-to-electric energy conversion efficiency () of 5.89 (JSC = 12.14 mA/cm2, VOC = 690 V, fill factor = 0.699) under Air Mass (AM) 1.5 sunlight, while the reference `cis-Ru(4,4'-dinonyl-2,2'-bipyridine)(Ln)(NCS)2', Z907 sensitized solar cell exhibited -value of 5.17% (JSC = 11.93 mA/cm2, VOC = 650 V, fill factor = 0.666). TGA analysis of H101 showed extended thermal-stability and under continuous light exposure and aging at 55°C, the DSSC retained 85% of its initial -value, while under comparable conditions Z907 sensitized solar cell retained 88%. As compared to 4,4'-dinonyl-2,2'-bipyridine in Z907, the new ancillary bipyridyl ligand `4,4'-bis(3,5-di-tert-butylphenyl)-2,2'-bipyridine’ in H101 shifts the absorption bands remarkably towards blue. The Density Functional Theory (DFT) and Time-Dependent DFT excited state calculations of the new sensitizer show that the first three HOMOs have t2g character with sizeable mixing from the NCS ligands with -bonding orbitals of 4,4'-bis(3,5-di-tert-butylphenyl)-2,2'-bipyridine. The LUMO is a *-orbital localized on the 4,4-dicarboxylic acid-2,2'-bipyridine and higher un-occupied frontier orbitals have *-combinations with 4,4'-bis(3,5-di-tert-butylphenyl)-2,2'-bipyridine.

  17. Crystal structures of three co-crystals of 4,4′-bipyridyl with 4-alkoxybenzoic acids: 4-ethoxybenzoic acid–4,4′-bipyridyl (2/1, 4-n-propoxybenzoic acid–4,4′-bipyridyl (2/1 and 4-n-butoxybenzoic acid–4,4′-bipyridyl (2/1

    Directory of Open Access Journals (Sweden)

    Yohei Tabuchi

    2015-11-01

    Full Text Available The crystal structures of three hydrogen-bonded co-crystals of 4-alkoxybenzoic acid–4,4′-bipyridyl (2/1, namely, 2C9H10O3·C10H8N2, (I, 2C10H12O3·C10H8N2, (II and 2C11H14O3·C10H8N2, (III, have been determined at 93 K. Although the structure of (I has been determined in the space group P21 with Z = 4 [Lai et al. (2008. J. Struct. Chem. 49, 1137–1140], the present study shows that the space group is P21/n with Z = 4. In each crystal, the components are linked by O—H...N hydrogen bonds, forming a linear hydrogen-bonded 2:1 unit of the acid and the base. The 2:1 unit of (I adopts nearly pseudo-C2 symmetry, viz. twofold rotation around an axis passing through the mid-point of the central C—C bond of 4,4′-bipyridyl, while the units of (II and (III, except for the terminal alkyl chains, have pseudo-inversion symmetry. The 2:1 units of (I, (II and (III are linked via C—H...O hydrogen bonds, forming sheet, double-tape and tape structures, respectively.

  18. Premalignant and neoplastic skin lesions associated with occupational exposure to “tarry” byproducts during manufacture of 4,4'-bipyridyl

    OpenAIRE

    Bowra, G T; Duffield, D. P.; Osborn, A J; Purchase, I F H

    1982-01-01

    ABSTRACT Skin lesions have been identified in 20 workers manufacturing 4,4'-bipyridyl. The lesions were on the face, neck, and backs of the hands and arms. Larger localised lesions were removed surgically and examined histopathologically, but other lesions have been treated topically with fluorouracil cream. Histological diagnosis showed a progression from keratosis to Bowen's disease and, in six cases, to squamous cell carcinoma. Over 550 individuals associated with 4,4'-bipyridyl processes ...

  19. Rectification in tunneling junctions: 2,2'-bipyridyl-terminated n-alkanethiolates.

    Science.gov (United States)

    Yoon, Hyo Jae; Liao, Kung-Ching; Lockett, Matthew R; Kwok, Sen Wai; Baghbanzadeh, Mostafa; Whitesides, George M

    2014-12-10

    Molecular rectification is a particularly attractive phenomenon to examine in studying structure-property relationships in charge transport across molecular junctions, since the tunneling currents across the same molecular junction are measured, with only a change in the sign of the bias, with the same electrodes, molecule(s), and contacts. This type of experiment minimizes the complexities arising from measurements of current densities at one polarity using replicate junctions. This paper describes a new organic molecular rectifier: a junction having the structure Ag(TS)/S(CH2)11-4-methyl-2,2'-bipyridyl//Ga2O3/EGaIn (Ag(TS): template-stripped silver substrate; EGaIn: eutectic gallium-indium alloy) which shows reproducible rectification with a mean r(+) = |J(+1.0 V)|/|J(-1.0 V)| = 85 ± 2. This system is important because rectification occurs at a polarity opposite to that of the analogous but much more extensively studied systems based on ferrocene. It establishes (again) that rectification is due to the SAM, and not to redox reactions involving the Ga2O3 film, and confirms that rectification is not related to the polarity in the junction. Comparisons among SAM-based junctions incorporating the Ga2O3/EGaIn top electrode and a variety of heterocyclic terminal groups indicate that the metal-free bipyridyl group, not other features of the junction, is responsible for the rectification. The paper also describes a structural and mechanistic hypothesis that suggests a partial rationalization of values of rectification available in the literature.

  20. Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

    Energy Technology Data Exchange (ETDEWEB)

    Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor (Malaysia)

    2015-09-25

    The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by {sup 1}H, 2D cosy and {sup 13}C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant K{sub b} = 1.19 × 10{sup 3} ± 0.08 M{sup −1}.

  1. Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

    International Nuclear Information System (INIS)

    The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1H, 2D cosy and 13C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant Kb = 1.19 × 103 ± 0.08 M−1

  2. Professional AngularJS

    CERN Document Server

    Karpov, Valeri

    2015-01-01

    A comprehensive guide to AngularJS, Google's open-source client-side framework for app development. Most of the existing guides to AngularJS struggle to provide simple and understandable explanations for more advanced concepts. As a result, some developers who understand all the basic concepts of AngularJS struggle when it comes to building more complex real-world applications. Professional AngularJS provides a thorough understanding of AngularJS, covering everything from basic concepts, such as directives and data binding, to more advanced concepts like transclusion, build systems, and auto

  3. Synthesis, structure and spectroscopic properties of complexes of rare earth dithiocarbamates with 2,2{prime}-bipyridyl or 1, 10-phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Chengyong Su; Minyu Tan; Ning Tang; Xinmin Gan; Weisheng Liu [Lanzhou Univ. (China)] [and others

    1996-05-01

    Two series of rare earth complexes with the general formula [RE(Me{sub 2}Dtc){sub 3}](RE = La,Pr,Nd,Sm-Yb, Y;Me{sub 2}Dtc = N,N-dimethyldithiocarbamate; bipy = 2,2{prime}-bipyridyl) and [RE(Et{sub 2-}Dtc){sub 3}(phen)](RE = La,Pr,Nd,Sm-Lu, Y;Et{sub 2}Dtc = N,N-diethyldithiocarbamate; phen = 1, 10-phenanthroline) have been prepared and some of their chemical properties, IR spectra, electronic spectra and conductivity properties are reported. The structures of [Eu(Me{sub 2}Dtc){sub 3}(bipy)] and [Eu(Et{sub 2}Dtc){sub 3}(phen)] have been determined by single-crystal X-ray diffraction methods. [Eu(Et{sub 2}Dtc){sub 3}(phen)] crystallizes in the tetragonal system, space group I4{sub 1}/a with a = 16.753(1), c = 39.523 (3) {angstrom} and Z = 16, while [Eu(Et{sub 2}Dtc){sub 3}(phen)]crystallizes in the monoclinic system, space group P2{sub 1}/c with a = 17.029(3), b = 10.652(3), c = 18.726(3) {angstrom}, {beta} = 96.41(4){degrees} and Z = 4. The central Eu(III) atoms are both octa-coordinated and in a distorted square antiprismatic geometry, each being coordinated to six sulphur atoms of three bidentate dithiocarbamates and to two nitrogen atoms of bipy or phen ligands. Spectrum analyses indicate that both Me{sub 2}Dtc and Et{sub 2}Dtc show similar coordination structures in all complexes.

  4. Factors affecting the electrochemical regeneration of NADH by (2,2'-bipyridyl) (pentamethylcyclopentadienyl)-rhodium complexes: impact on their immobilization onto electrode surfaces.

    Science.gov (United States)

    Walcarius, Alain; Nasraoui, Rihab; Wang, Zhijie; Qu, Fengli; Urbanova, Veronika; Etienne, Mathieu; Göllü, Mehmet; Demir, Ayhan S; Gajdzik, Janine; Hempelmann, Rolf

    2011-08-01

    Complexes of the (2,2'-bipyridyl) (pentamethylcyclopentadienyl)-rhodium family ([Cp*Rh(bpy)Cl](+), which is actually hydrolyzed in the form of [Cp*Rh(bpy)H(2)O](2+) in aqueous medium) are suitable solution-phase mediators likely to regenerate nicotinamide cofactors associated to dehydrogenases involved in many biocatalytic applications. Their practical application as bioelectrocatalysts, e.g., in fine chemicals synthesis or biosensors, remains however restricted to their durable immobilization in an active form onto solid electrode surfaces. This paper reports some new observations on the electrocatalytic properties of this mediator towards NAD(+) reduction, notably the critical effect of pH and cofactor-to-mediator concentration ratio, and investigates the behavior of a series of ([Cp*Rh(bpy)Cl](+)) derivatives bearing various substituents on the bipyridine ligand in view of their subsequent integration in electrochemical bioreactors. It will be shown that such compounds containing S- or N- moieties (i.e., often used as precursors to functionalize electrode surfaces) lead to inactivation of the electrocatalyst because their interaction with the Rh center prevents the formation of the active rhodium hydride complex. It was thus necessary to find another strategy of immobilization, and we found that adsorption of [Cp*Rh(bpy)Cl](+) by π-stacking on single-walled carbon nanotubes is an effective mean to reach this goal, leading to efficient and stable catalytic responses for NAD(+) reduction. Preliminary electroenzymatic experiments in the presence of d-sorbitol dehydrogenase further point out the interest of this approach for bioelectrocatalysis purposes and provide the proof-of-concept for this immobilization strategy.

  5. Synthesis, Characterization, and Antifungal Studies of Cr(III Complex of Norfloxacin and Bipiridyl Ligand

    Directory of Open Access Journals (Sweden)

    Anamika Debnath

    2014-01-01

    Full Text Available A novel slightly distorted octahedral complex of Cr(III of norfloxacin (Nor with the formula [CrIII(Nor(BipyCl2]Cl·2CH3OH has been synthesized hydrothermally in the presence of a N-containing heterocyclic compound 2,2′-bipyridyl (Bipy. The complex was characterized with FT-IR, elemental analysis, UV-visible spectroscopy, and X-ray crystallography. Spectral studies suggest that the Nor acts as a deprotonated bidentate ligand. Thermal studies were also carried out. The synthesised complex was screened against four fungi Pythium aphanidermatum (PA, Sclerotinia rolfsii (SR, Rhizoctonia solani (RS, and Rhizoctonia bataticola (RB.

  6. (Carbonato-κ2O,O′bis(5,5′-dimethyl-2,2′-bipyridyl-κ2N,N′cobalt(III bromide trihydrate

    Directory of Open Access Journals (Sweden)

    Kannan Arun Kumar

    2012-04-01

    Full Text Available In the title complex, [Co(CO3(C12H12N22]Br·3H2O, the CoIII cation has a distorted octahedral coordination environment. It is chelated by four N atoms of two different 5,5′-dimethyl-2,2′-bipyridyl (dmbpy ligands in axial and equatorial positions, and by two O atoms of a carbonate anion completing the equatorial positions. Although the water molecules are disordered and their H atoms were not located, there are typical O...O distances between 2.8 and 3.0 Å, indicating O—H...O hydrogen bonding. The crystal packing is consolidated by C—H...O and C—H...Br hydrogen bonds, as well as π–π stacking interactions between adjacent pyridine rings of the dmbpy ligands, with centroid–centroid distances of 3.694 (3 and 3.7053 (3 Å.

  7. On Angular Momentum

    Science.gov (United States)

    Schwinger, J.

    1952-01-26

    The commutation relations of an arbitrary angular momentum vector can be reduced to those of the harmonic oscillator. This provides a powerful method for constructing and developing the properties of angular momentum eigenvectors. In this paper many known theorems are derived in this way, and some new results obtained. Among the topics treated are the properties of the rotation matrices; the addition of two, three, and four angular momenta; and the theory of tensor operators.

  8. Partonic orbital angular momentum

    Science.gov (United States)

    Arash, Firooz; Taghavi-Shahri, Fatemeh; Shahveh, Abolfazl

    2013-04-01

    Ji's decomposition of nucleon spin is used and the orbital angular momentum of quarks and gluon are calculated. We have utilized the so called valon model description of the nucleon in the next to leading order. It is found that the average orbital angular momentum of quarks is positive, but small, whereas that of gluon is negative and large. Individual quark flavor contributions are also calculated. Some regularities on the total angular momentum of the quarks and gluon are observed.

  9. Quark Orbital Angular Momentum

    OpenAIRE

    Burkardt Matthias

    2015-01-01

    Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asy...

  10. Electronic structure and electro-optical properties of ion radicals formed during the reduction of N, N'-dialkylsubstituted salts of 4,4'-bipyridyl

    Science.gov (United States)

    Zakirov, M. I.; Efimov, N. N.; Mel'nikov, P. V.; Nodova, E. L.; Minin, V. V.

    2013-08-01

    Symmetric N, N'-disubstituted salts of 4,4'-bipyridyl (viologens) are synthesized and described. It is shown by cyclic voltammetry that disubstituted salts of 4,4'-bipyridyl have a tendency toward reversible two-electron reduction. Normal first and second step oxidation-reduction potentials with respect to saturated silver chloride electrodes at various potential scan rates are found. The spectra of the high-resolution electron paramagnetic resonance of viologen cation radicals formed during the reduction of N, N'-disubstituted salts of 4,4'-bipyridyl are obtained and interpreted. It is established that the nature of substitutes and counterions in a viologen molecule considerably influences the distribution of its spin density, voltammetric curves, and electro-optical properties.

  11. Crystal structures of copper(II) nitrate complexes containing 4,4'-bipyridyl and halogen-substituted 2-[(2-hydroxyethylimino)methyl]phenols

    International Nuclear Information System (INIS)

    The crystal structures of (μ-4,4'-bipyridyl)-di{nitrato-2,4-dibromo-6-[(2-hydroxyethylimino)methyl] phenolo (1-)copper} (I), (μ-4,4'-bipyridyl)-di{nitrato-2,4-dichloro-6-[(2-hydroxyethylimino)methyl] phenolo(1-)copper} (II), and (μ-4,4'-bipyridyl)-{4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(2-) copper-nitrato-4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(1-)copper} tetrahydrate (III) are determined. The crystal structures of compounds I and II contain binuclear complexes, in which each copper atom is coordinated by the singly deprotonated tridentate molecule of the corresponding azomethine, the monodentate nitrate ion, and bipyridyl that plays the role of a bridge between the central atoms. In the structures of compounds I and II, the coordination polyhedra of the copper atoms are slightly distorted tetragonal pyramids. The pyramid base is formed by the imine and bipyridyl nitrogen atoms and the phenol and alcohol oxygen atoms. The axial vertices of the pyramids are occupied by the oxygen atoms of the monodentate nitrato groups. The crystal structure of compound III involves tetranuclear complexes in which the coordination polyhedra of the central copper atoms are (4 + 1 + 1) bipyramids. The base of these bipyramids is formed by the imine and bipyridyl nitrogen atoms and the phenol and alcohol oxygen atoms. One apical vertex is occupied by the bridging phenol oxygen atom of the nearest complex. The sixth coordination site of the first copper atom is occupied by the chlorine atom of the salicylidene fragment of the neighboring complex related to the initial complex through the center of symmetry. In turn, the sixth coordination site of the second copper atom is occupied by the oxygen atom of the monodentate nitrato group.

  12. DVL Angular Velocity Recorder

    Science.gov (United States)

    Liebe, Wolfgang

    1944-01-01

    In many studies, especially of nonstationary flight motion, it is necessary to determine the angular velocities at which the airplane rotates about its various axes. The three-component recorder is designed to serve this purpose. If the angular velocity for one flight attitude is known, other important quantities can be derived from its time rate of change, such as the angular acceleration by differentiations, or - by integration - the angles of position of the airplane - that is, the angles formed by the airplane axes with the axis direction presented at the instant of the beginning of the motion that is to be investigated.

  13. Quark Orbital Angular Momentum

    Directory of Open Access Journals (Sweden)

    Burkardt Matthias

    2015-01-01

    Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

  14. Optical Angular Momentum

    International Nuclear Information System (INIS)

    For many years the Institute of Physics has published books on hot topics based on a collection of reprints from different journals, including some remarks by the editors of each volume. The book on Optical Angular Momentum, edited by L Allen, S M Barnett and M J Padgett, is a recent addition to the series. It reproduces forty four papers originally published in different journals and in a few cases it provides direct access to works not easily accessible to a web navigator. The collection covers nearly a hundred years of progress in physics, starting from an historic 1909 paper by Poynting, and ending with a 2002 paper by Padgett, Barnett and coworkers on the measurement of the orbital angular momentum of a single photon. The field of optical angular momentum has expanded greatly, creating an interdisciplinary attraction for researchers operating in quantum optics, atomic physics, solid state physics, biophysics and quantum information theory. The development of laser optics, especially the control of single mode sources, has made possible the specific design of optical radiation modes with a high degree of control on the light angular momentum. The editors of this book are important figures in the field of angular momentum, having contributed to key progress in the area. L Allen published an historical paper in 1999, he and M J Padgett (together with M Babiker) produced few years ago a long review article which is today still the most complete basic introduction to the angular momentum of light, while S M Barnett has contributed several high quality papers to the progress of this area of physics. The editors' choice provides an excellent overview to all readers, with papers classified into eight different topics, covering the basic principles of the light and spin and orbital angular momentum, the laboratory tools for creating laser beams carrying orbital angular momentum, the optical forces and torques created by laser beams carrying angular momentum on

  15. Average Angular Velocity

    OpenAIRE

    Van Essen, H.

    2004-01-01

    This paper addresses the problem of the separation of rotational and internal motion. It introduces the concept of average angular velocity as the moment of inertia weighted average of particle angular velocities. It extends and elucidates the concept of Jellinek and Li (1989) of separation of the energy of overall rotation in an arbitrary (non-linear) $N$-particle system. It generalizes the so called Koenig's theorem on the two parts of the kinetic energy (center of mass plus internal) to th...

  16. Angular velocity discrimination

    Science.gov (United States)

    Kaiser, Mary K.

    1990-01-01

    Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

  17. Antioxidant activities of nano-bubble hydrogen-dissolved water assessed by ESR and 2,2'-bipyridyl methods.

    Science.gov (United States)

    Kato, Shinya; Matsuoka, Daigo; Miwa, Nobuhiko

    2015-08-01

    We prepared nano-bubble hydrogen-dissolved water (nano-H water) which contained hydrogen nano-bubbles of hydrogen water (0.075 ppm, +49 mV), and 2.66 for manufactured hydrogen water (0.788 ppm, -614 mV), whereas the nano-H water (0.678 ppm, -644 mV) exhibited 2.05, showing the superiority of nano-H water to other types of hydrogen water in terms of OH-scavenging activity. Then, the reduction activity of nano-H water was assessed spectrophotometrically by the 2,2'-bipyridyl method. Differential absorbance at 530 nm was in the order: 0.018 for pure water, 0.055 for tap water, 0.079 for nano-H water, 0.085 for commercially available hydrogen water, and 0.090 for manufactured hydrogen water, indicating a prominent reduction activity of hydrogen water and nano-H water against oxidation in ascorbate-coupled ferric ion-bipyridyl reaction. Thus, nano-H water has an improved antioxidant activity as compared to hydrogen water of similar DH-level, indicating the more marked importance of nano-bubbles rather than the concentration of hydrogen in terms of OH-scavenging. PMID:26042683

  18. Metamaterial Broadband Angular Selectivity

    CERN Document Server

    Shen, Yichen; Wang, Zhiyu; Wang, Li; Celanovic, Ivan; Ran, Lixin; Joannopoulos, John D; Soljacic, Marin

    2014-01-01

    We demonstrate how broadband angular selectivity can be achieved with stacks of one-dimensionally periodic photonic crystals, each consisting of alternating isotropic layers and effective anisotropic layers, where each effective anisotropic layer is constructed from a multilayered metamaterial. We show that by simply changing the structure of the metamaterials, the selective angle can be tuned to a broad range of angles; and, by increasing the number of stacks, the angular transmission window can be made as narrow as desired. As a proof of principle, we realize the idea experimentally in the microwave regime. The angular selectivity and tunability we report here can have various applications such as in directional control of electromagnetic emitters and detectors.

  19. Fluidic angular velocity sensor

    Science.gov (United States)

    Berdahl, C. M. (Inventor)

    1986-01-01

    A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input is described. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

  20. Angular Scaling In Jets

    Energy Technology Data Exchange (ETDEWEB)

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC

    2012-02-17

    We introduce a jet shape observable defined for an ensemble of jets in terms of two-particle angular correlations and a resolution parameter R. This quantity is infrared and collinear safe and can be interpreted as a scaling exponent for the angular distribution of mass inside the jet. For small R it is close to the value 2 as a consequence of the approximately scale invariant QCD dynamics. For large R it is sensitive to non-perturbative effects. We describe the use of this correlation function for tests of QCD, for studying underlying event and pile-up effects, and for tuning Monte Carlo event generators.

  1. Average Angular Velocity

    CERN Document Server

    Essén, H

    2003-01-01

    This paper addresses the problem of the separation of rotational and internal motion. It introduces the concept of average angular velocity as the moment of inertia weighted average of particle angular velocities. It extends and elucidates the concept of Jellinek and Li (1989) of separation of the energy of overall rotation in an arbitrary (non-linear) $N$-particle system. It generalizes the so called Koenig's theorem on the two parts of the kinetic energy (center of mass plus internal) to three parts: center of mass, rotational, plus the remaining internal energy relative to an optimally translating and rotating frame.

  2. Induced Angular Momentum

    Science.gov (United States)

    Parker, G. W.

    1978-01-01

    Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)

  3. Ylide Ligands

    OpenAIRE

    Esteban P. Urriolabeitia

    2010-01-01

    The use of ylides of P, N, As, or S as ligands toward transition metals is still a very active research area in organometallic chemistry. This fact is mainly due to the nucleophilic character of the ylides and to their particular bonding properties and coordination modes. They can behave as monodentate or bidentate chelate or bridging species, they can be used as chiral auxiliary reagents, and they are interesting reaction intermediates or useful starting materials in a wide ...

  4. Replacing the hydrogen in the intermolecular hydrogen bond of the cyanuric acid-bipyridyl adduct by Ag(I)

    Indian Academy of Sciences (India)

    K Sivashankar; Anupama Ranganathan; V R Pedireddi

    2000-04-01

    A complex between cyanuric acid (CA), 4,4′-bipyridyl (BP) and Ag(I), with the composition, [Ag2(C3H2N3O3-N)2 (C10H8N2-N)] has been prepared. Crystal structure analysis shows that it has a chain structure in which the CA molecules are linked to the BP units through silver atoms by the formation of N-Ag-N bonds, wherein one of the hydrogens of CA is replaced by Ag(I), showing thereby the chains connected to one another by N-H${\\ldots}$O hydrogen bonds formed between the CA molecules. This intermolecular chain structure resembles the chain structure of the CA.BP adduct where CA-BP-CA chains formed by N-H${\\ldots}$N hydrogen bonds are linked to one another by N-H${\\ldots}$O hydrogen bonds between the CA molecules.

  5. Quantum Heuristics of Angular Momentum

    Science.gov (United States)

    Levy-Leblond, Jean-Marc

    1976-01-01

    Discusses the quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus, without using operators or commutation relations. (MLH)

  6. Angular momentum projected semiclassics

    Science.gov (United States)

    Hasse, Rainer W.

    1987-06-01

    By using angular momentum projected plane waves as wave functions, we derive semiclassical expressions for the single-particle propagator, the partition function, the nonlocal density matrix, the single-particle density and the one particle-one hole level density for fixed angular momentum and fixed z-component or summed over the z-components. Other quantities can be deduced from the propagator. In coordinate space ( r, r') the relevant quantities depend on |r-r'| instead of | r- r'| and in Wigner space ( R, P) they become proportional to the angular momentum constraints δ(| R × P|/ h̵-l) and δ( R × P) z/ h̵-m) . As applications we calculate the single-particle and one-particle-one hole level densities for harmonic oscillator and Hill-Wheeler box potentials and the imaginary part of the optical potential and its volume integral with an underlying harmonic oscillator potential and a zero range two-body interaction.

  7. Separation of americium(III) and europium(III) from nitrate medium using a binary mixture of Cyanex-301 with neutral donor ligands

    International Nuclear Information System (INIS)

    Separation behaviour of Am3+ and Eu3+ was investigated from aqueous nitrate medium using a binary mixture of Cyanex-301 (bis(2,4,4- trimethylpentyl) dithiophosphinic acid) and several N, O or S donor ligands such as 1,10-phenanthroline (phen), TPTZ (2,4,6- tri(2-pyridyl)- 1,3,5- triazine), 2,2'-bipyridyl(bipy), hexa thia 18 crown 6 (S618C6), TBP (tri-n-butyl phosphate), TBTP (tri-n-butyl thiophosphate) in toluene. The S.F. values of >40,000 obtained with bipy and phen are the highest reported to date. (author)

  8. Quark Orbital Angular Momentum

    Science.gov (United States)

    Burkardt, Matthias

    2016-06-01

    Generalized parton distributions provide information on the distribution of quarks in impact parameter space. For transversely polarized nucleons, these impact parameter distributions are transversely distorted and this deviation from axial symmetry leads on average to a net transverse force from the spectators on the active quark in a DIS experiment. This force when acting along the whole trajectory of the active quark leads to transverse single-spin asymmetries. For a longitudinally polarized nucleon target, the transverse force implies a torque acting on the quark orbital angular momentum (OAM). The resulting change in OAM as the quark leaves the target equals the difference between the Jaffe-Manohar and Ji OAMs.

  9. AngularJS directives

    CERN Document Server

    Vanston, Alex

    2013-01-01

    This book uses a practical, step-by-step approach, starting with how to build directives from the ground up before moving on to creating web applications comprised of multiple modules all working together to provide the best user experience possible.This book is intended for intermediate JavaScript developers who are looking to enhance their understanding of single-page web application development with a focus on AngularJS and the JavaScript MVC frameworks.It is expected that readers will understand basic JavaScript patterns and idioms and can recognize JSON formatted data.

  10. Detection of pyrrolizidine alkaloids using flow analysis with both acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence

    International Nuclear Information System (INIS)

    For the first time, analytically useful chemiluminescence was elicited from the reactions of the pyrrolizidine alkaloids. Heliotrine, retronecine, supinine, monocrotaline and echinatine N-oxide yielded chemiluminescence upon reaction with tris(2,2'-bipyridyl)ruthenium(II) whilst lasiocarpine, its N-oxide and supinine elicited light upon reaction with acidic potassium permanganate. Detection limits for heliotrine were 1.25 x 10-7 M and 9 x 10-9 M for tris(2,2'-bipyridyl)ruthenium(III) perchlorate with flow injection analysis (FIA) and the silica-immobilised reagent (4-[4-(dichloromethylsilanyl)-butyl]-4'-methyl-2,2'-bipyridine)bis (2,2'-bipyridyl)ruthenium(II) with sequential injection analysis (SIA), respectively. Lasiocarpine was detectable at 1.4 x 10-7 M using acidic potassium permanganate with FIA. Additionally, the silica-immobilised reagent was optimised with respect to the oxidant (ammonium ceric nitrate) concentration and the aspiration times which afforded a detection limit for codeine of 5 x 10-10 M using SIA

  11. Supramolecular Terbium-SIP Complex Pillared by 4,4'-Bipyridyl,{[Tb(SIP)(H2O)5]2(bpy)3(H2O))n:Synthesis,Crystal Structure and Photoluminescence

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Ling; LIU Qing-Yan; XU Li; ZHONG Sheng-Liang

    2008-01-01

    The supramolecular terbium complex,{[To(SIP)(H2O)5]2(bpy)3(H2O)}n(NaH2SIP=5-sulfoisophthalic acid monosodium salt and bpy=4,4'-bipyridyl),has been synthesized by the hydrothermal reaction of Tb4O7 with NaH2SIP and bpy at 165℃,and characterized by single-crystal X-ray diffraction,elemental analysis,IR spectrum,powder X-ray diffraction and photoluminescence spectrum.It crystallizes in a monoclinic system,space group C2/c,with a=30.6840(1),b=10.9206(2),c=17.4967(3)(A),β=111.931(1)°,V=5438.65(14)(A)3,Z=4,C46H52N6O25S2Tb2,Mr=1470.90,Dc=1.796g/cm3,μ=2.747mm-1,F(000)=2928,the final R=0.0654 and wR=0.1322 for 3806 observed reflections with Ⅰ>2σ(Ⅰ).In the neural [Tb(SIP)(H2O)5]2 motif,the Tb(Ⅲ)ions are linked by the SIP ligands to form a one-dimensional zigzag chain propagating along the c axis.The zigzag chains are linked together by hydrogen bonds and π-π stacking interactions to form a two-dimensional supramolecular framework.The uncoordinated bpy molecules act as pillars to extend the two-dimensional sheets into a distinctive pillared three-dimensional supramolecular structure through O-H…N hydrogen bonds.The photoluminescence of the complex was investigated at room temperature in the solid state.

  12. Orbital angular momentum microlaser

    Science.gov (United States)

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M.; Feng, Liang

    2016-07-01

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes.

  13. Orbital angular momentum microlaser.

    Science.gov (United States)

    Miao, Pei; Zhang, Zhifeng; Sun, Jingbo; Walasik, Wiktor; Longhi, Stefano; Litchinitser, Natalia M; Feng, Liang

    2016-07-29

    Structured light provides an additional degree of freedom for modern optics and practical applications. The effective generation of orbital angular momentum (OAM) lasing, especially at a micro- and nanoscale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode. The polarization associated with OAM lasing can be further manipulated on demand, creating a radially polarized vortex emission. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications in both quantum and classical regimes. PMID:27471299

  14. On the relation between angular momentum and angular velocity

    Science.gov (United States)

    Silva, J. P.; Tavares, J. M.

    2007-01-01

    Students of mechanics usually have difficulties when they learn about the rotation of a rigid body. These difficulties are rooted in the relation between angular momentum and angular velocity, because these vectors are not parallel, and we need in general to utilize a rotating frame of reference or a time dependent inertia tensor. We discuss a series of problems that introduce both difficulties.

  15. Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

    Directory of Open Access Journals (Sweden)

    Kübra Çevik

    2015-08-01

    Full Text Available Objective(s:The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods:The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acidonbiofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa  PAK01,P. aeruginosa PAK02 and P. aeruginosa PAK03 were investigated, based on crystal violet assay, and swarming motility test. Results:The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84% and kojic acid (68% presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation.

  16. Electrogenerated chemiluminescence: An oxidative-reductive mechanism between quinolone antibiotics and tris(2,2'-bipyridyl)ruthenium(II)

    Energy Technology Data Exchange (ETDEWEB)

    Burkhead, Matthew S.; Wang, Heeyoung; Fallet, Marcel [Department of Chemistry, Creighton University, Omaha, NE 68178 (United States); Gross, Erin M. [Department of Chemistry, Creighton University, Omaha, NE 68178 (United States)], E-mail: eringross@creighton.edu

    2008-04-21

    The cyclic voltammetry and electrogenerated chemiluminescent (ECL) reactions of a series of quinolone and fluoroquinolone antibiotics were investigated in a flow injection analysis (FIA) system. 7-Piperazinyl fluoroquinolone antibiotics were found to participate as a coreactant in an oxidative-reductive ECL mechanism with tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy){sub 3}{sup 2+}) as the luminescent reagent. The reaction mechanism was investigated in order to understand and optimize the processes leading to light emission. The optimal conditions included a solution pH {approx}7 at a flow rate of 3.0 mL min{sup -1} with no added organic modifier and application of 1.2 V vs. a Pt quasi-reference electrode (QRE). Fluoroquinolones containing a tertiary distal nitrogen on the piperazine ring, such as enrofloxacin and ofloxacin, reacted to produce more intense ECL than those with a secondary nitrogen, such as ciprofloxacin and norfloxacin. The method linear range, precision, detection limits, and sensitivity for the detection of enrofloxacin and ciprofloxacin were compared to that of tripropylamine. The method was applied to the determination of the ciprofloxacin content in a pharmaceutical preparation. The assay is discussed in terms of its analytical figures of merit, ease of use, speed, accuracy and application to pharmaceutical samples.

  17. Electrochemiluminescence from tris(2,2′-bipyridyl) ruthenium (Ⅱ) in the presence of aminocarboxylic acid co-reactants

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Due to the highly sensitive electrochemiluminescence (ECL), tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy)32+) is often used in the field of bioarrays with the help of co-reactants. However, the generally used co-reactant, tripropylamine (TPA), is toxic, corrosive and volatile. Therefore, the search for safe, sensitive and economical co-reactants is critical. Herein, three aminocarboxylic acids, ethylenediamine-tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and 2-hydroxyethylethylene diaminetriacetic acid (HEDTA), have been investigated as potential co-reactants for promoting Ru(bpy)32+ ECL behaviour. A possible ECL mechanism is also presented. The experimental results suggested that the co-reactants have a different ECL behaviour compared to TPA, such as different pH- and surfactant-responses. The detection limits of Ru(bpy)32+ using NTA, EDTA and HEDTA as co-reactants are 1, 60 and 680 fmol·L-1, respectively. The results indicate that NTA has a much higher efficiency than TPA to excite Ru(bpy)3 2+ ECL under their own optimal conditions. NTA could be widely used in many fields because it is less toxic, corrosive and volatile than TPA. Moreover, using Ru(bpy)3 2+ ECL, a sensitive method for the detection of aminocarboxylic acids is also developed. An improvement of four orders of magnitude in detection limits is obtained for EDTA compared to the known Ru(bpy) 3 2+ chemiluminescent methods.

  18. Angular momentum in subbarrier fusion

    International Nuclear Information System (INIS)

    We have measured the ratio of the isomer to ground-state yields of 137Ce produced in the fusion reactions 128Te(12C,3n), 133Cs(7Li,3n), 136Ba(3He,2n), 136Ba(4He,3n), and 137Ba(3He,3n), from energies above the Coulomb barrier to energies typically 20--30% below the barrier by observing the delayed x- and γ-ray emission. We deduce the average angular momentum, , from the measured isomer ratios with a statistical model. In the first three reactions we observe that the values of exhibit the behavior predicted for low energies and the expected variation with the reduced mass of the entrance channel. We analyze these data and the associated cross sections with a barrier penetration model that includes the coupling of inelastic channels. Measurements of average angular momenta and cross sections made on other systems using the γ-multiplicity and fission-fragment angular correlation techniques are then analyzed in a similar way with this model. The discrepancies with theory for the γ-multiplicity data show correlations in cross section and angular momentum that suggest a valid model can be found. The measurements of angular momentum using the fission fragment angular correlation technique, however, do not appear reconcilable with the energy dependence of the cross sections. This systematic overview suggests, in particular, that our current understanding of the relationship of angular momentum and anisotropy in fission fragment angular correlations is incomplete. 26 refs

  19. Intrinsic Angular Momentum of Light.

    Science.gov (United States)

    Santarelli, Vincent

    1979-01-01

    Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

  20. Angular signal radiography.

    Science.gov (United States)

    Li, Panyun; Zhang, Kai; Bao, Yuan; Ren, Yuqi; Ju, Zaiqiang; Wang, Yan; He, Qili; Zhu, Zhongzhu; Huang, Wanxia; Yuan, Qingxi; Zhu, Peiping

    2016-03-21

    Microscopy techniques using visible photons, x-rays, neutrons, and electrons have made remarkable impact in many scientific disciplines. The microscopic data can often be expressed as the convolution of the spatial distribution of certain properties of the specimens and the inherent response function of the imaging system. The x-ray grating interferometer (XGI), which is sensitive to the deviation angle of the incoming x-rays, has attracted significant attention in the past years due to its capability in achieving x-ray phase contrast imaging with low brilliance source. However, the comprehensive and analytical theoretical framework is yet to be presented. Herein, we propose a theoretical framework termed angular signal radiography (ASR) to describe the imaging process of the XGI system in a classical, comprehensive and analytical manner. We demonstrated, by means of theoretical deduction and synchrotron based experiments, that the spatial distribution of specimens' physical properties, including absorption, refraction and scattering, can be extracted by ASR in XGI. Implementation of ASR in XGI offers advantages such as simplified phase retrieval algorithm, reduced overall radiation dose, and improved image acquisition speed. These advantages, as well as the limitations of the proposed method, are systematically investigated in this paper. PMID:27136780

  1. Angular momentum evolution for galaxies

    CERN Document Server

    Pedrosa, Susana

    2015-01-01

    Using cosmological hydrodynamics simulations we study the angular momentum content of the simulated galaxies in relation with their morphological type. We found that not only the angular momentum of the disk component follow the expected theoretical relation, Mo, Mao & Whiye (1998), but also the spheroidal one, with a gap due to its lost of angular momentum, in agreement with Fall & Romanowsky (2013),. We also found that the galaxy size can plot in one general relation, despite the morphological type, as found by Kravtsov (2013).

  2. AngularJS testing cookbook

    CERN Document Server

    Bailey, Simon

    2015-01-01

    This book is intended for developers who have an understanding of the basic principles behind both AngularJS and test-driven development. You, as a developer, are interested in eliminating the fear related to either introducing tests to an existing codebase or starting out testing on a fresh AngularJS application. If you're a team leader or part of a QA team with the responsibility of ensuring full test coverage of an application, then this book is ideal for you to comprehend the full testing scope required by your developers. Whether you're new to or are well versed with AngularJS, this book

  3. Laser Detection Of Latent Fingerprints: Tris(2,2'-Bipyridyl)Ruthenium(II) Chloride Hexahydrate As A Staining Dye For Time-Resolved Imaging

    Science.gov (United States)

    Menzel, E. R.

    1988-04-01

    The compound tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate is suitable for laser detection of latent fingerprints on difficult surfaces such as wood and masking tape, as well as surfaces such as polyethylene, metal, etc. The fingerprint treatment can Involve either dusting with powder blended with this compound or by solution staining. The compound displays a strong d-n phosphorescence with a lifetime of about 10-6 and is thus very well suited for time-resolved imaging to suppress background fluorescence.

  4. Is the bipyridyl thorium metallocene a low-valent thorium complex? A combined experimental and computational study

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wenshan; Lukens, Wayne W.; Zi, Guofu; Maron, Laurent; Walter, Marc D.

    2012-01-12

    Bipyridyl thorium metallocenes [5-1,2,4-(Me3C)3C5H2]2Th(bipy) (1) and [5-1,3-(Me3C)2C5H3]2Th(bipy) (2) have been investigated by magnetic susceptibility and computational studies. The magnetic susceptibility data reveal that 1 and 2 are not diamagnetic, but they behave as temperature independent paramagnets (TIPs). To rationalize this observation, density functional theory (DFT) and complete active space SCF (CASSCF) calculations have been undertaken, which indicated that Cp2Th(bipy) has indeed a Th(IV)(bipy2-) ground state (f0d0 2, S = 0), but the open-shell singlet (f0d1 1, S = 0) (almost degenerate with its triplet congener) is lying only 9.2 kcal/mol higher in energy. Complexes 1 and 2 react cleanly with Ph2CS to give [ 5-1,2,4-(Me3C)3C5H2]2Th[(bipy)(SCPh2)] (3) and [ 5-1,3-(Me3C)2C5H3]2Th[(bipy)(SCPh2)] (4), respectively, in quantitative conversions. Since no intermediates were observed experimentally, this reaction was also studied computationally. Coordination of Ph2CS to 2 in its S = 0 ground state is not possible, but Ph2CS can coordinate to 2 in its triplet state (S = 1) upon which a single electron transfer (SET) from the (bipy2-) fragment to Ph2CS followed by C-C coupling takes place.

  5. Electrochemiluminescence from tris(2,2'-bipyridyl) ruthenium (Ⅱ) in the presence of aminocarboxylic acid co-reactants

    Institute of Scientific and Technical Information of China (English)

    YIN XueBo; SHA BeiBei; HE XiWen

    2009-01-01

    Due to the highly sensitive electrochemiluminescence (ECL),tris(2,2'-bipyridyl) ruthenium(Ⅱ) (Ru(bpy)32+)is often used in the field of bioarrays with the help of co-reactants.However,the generally used co-reactant,tripropylamine (TPA),is toxic,corrosive and volatile.Therefore,the search for safe,sensitive and economical co-reactants is critical.Herein,three aminocarboxylic acids,ethylenediaminetetraacetic acid (EDTA),nitrilotriacetic acid (NTA),and 2-hydroxyethylethylene diaminetriacetic acid (HEDTA),have been investigated as potential co-reactants for promoting Ru(bpy)32+ ECL behaviour.A possible ECL mechanism is also presented.The experimental results suggested that the co-reactants have a different ECL behaviour compared to TPA,such as different pH-and surfactant-responses.The detection limits of Ru(bpy)32+ using NTA,EDTA and HEDTA as co-reactants are 1,60 and 680 fmoI.L1,respectively.The results indicate that NTA has a much higher efficiency than TPA to excite Ru(bpy)32+ ECL under their own optimal conditions.NTA could be widely used in many fields because it is less toxic,corrosive and volatile than TPA.Moreover,using Ru(bpy)32+ ECL,a sensitive method for the detection of aminocarboxylic acids is also developed.An improvement of four orders of magnitude in detection limits is obtained for EDTA compared to the known Ru(bpy)32+ chemiluminescent methods.

  6. Electrochemiluminescent determination of nicotine based on tri(2,2'-bipyridyl) ruthenium (II) complex through flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lin Mengshan [Department of Chemistry, Tamkang University, Tamsui 25137, Taiwan (China)], E-mail: mslin@mail.tku.edu.tw; Wang Junsheng; Lai Chienhung [Department of Chemistry, Tamkang University, Tamsui 25137, Taiwan (China)

    2008-11-01

    This paper describes the electrogenerated chemiluminescence (ECL) processes of Ru(bpy){sub 3}{sup 2+}/nicotine system at ITO working electrode. An ECL-based method for rapid and sensitive detection of nicotine in phosphate buffer solution at pH 8.0 is established. Strong ECL emission was observed at a positive potential of 1.4 V vs. Ag/AgCl. A possible ECL mechanism is proposed for the Ru(bpy){sub 3}{sup 2+}/nicotine system, the oxidation product of nicotine at the electrode surface reacts with the 3+ state of ruthenium bipyridyl (2+) complex and form ruthenium complex exited state ions and thus releases photons. Effect of pH (medium/electrolyte), working potential, buffer composition, buffer concentration, reactant and co-reactant (nicotine) concentration, flow rate and loop size on the ECL spectrum of the Ru(bpy){sub 3}{sup 2+}/nicotine were studied. At the optimized experimental conditions, lower detection limit for nicotine was observed as 1.2 nmol L{sup -1} (S/N = 3). Linear relationship between ECL current and concentration of nicotine was observed (up to 100 {mu}mol L{sup -1}) with R-value of 0.997. The relative standard deviation with 5 {mu}mol L{sup -1} concentration of nicotine for 20 analyses was only 1.4%. A 94% recovery rate was observed in a real sample analysis without any complications/disturbance in measurement. Interferences of humid acid, camphor and SDS were not observed in their presence in the sample solution. The established procedure for nicotine quantification manifests fascinating results and can be suggested for further applications.

  7. Electrochemiluminescent determination of nicotine based on tri(2,2'-bipyridyl) ruthenium (II) complex through flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Meng Shan; Wang, Jun Sheng; Lai, Chien Hung [Department of Chemistry, Tamkang University, Tamsui 25137 (China)

    2008-11-01

    This paper describes the electrogenerated chemiluminescence (ECL) processes of Ru(bpy){sub 3}{sup 2+}/nicotine system at ITO working electrode. An ECL-based method for rapid and sensitive detection of nicotine in phosphate buffer solution at pH 8.0 is established. Strong ECL emission was observed at a positive potential of 1.4 V vs. Ag/AgCl. A possible ECL mechanism is proposed for the Ru(bpy){sub 3}{sup 2+}/nicotine system, the oxidation product of nicotine at the electrode surface reacts with the 3+ state of ruthenium bipyridyl (2+) complex and form ruthenium complex exited state ions and thus releases photons. Effect of pH (medium/electrolyte), working potential, buffer composition, buffer concentration, reactant and co-reactant (nicotine) concentration, flow rate and loop size on the ECL spectrum of the Ru(bpy){sub 3}{sup 2+}/nicotine were studied. At the optimized experimental conditions, lower detection limit for nicotine was observed as 1.2 nmol L{sup -1} (S/N = 3). Linear relationship between ECL current and concentration of nicotine was observed (up to 100 {mu}mol L{sup -1}) with R-value of 0.997. The relative standard deviation with 5 {mu}mol L{sup -1} concentration of nicotine for 20 analyses was only 1.4%. A 94% recovery rate was observed in a real sample analysis without any complications/disturbance in measurement. Interferences of humid acid, camphor and SDS were not observed in their presence in the sample solution. The established procedure for nicotine quantification manifests fascinating results and can be suggested for further applications. (author)

  8. The integration of angular velocity

    OpenAIRE

    Boyle, Michael

    2016-01-01

    A common problem in physics and engineering is determination of the orientation of an object given its angular velocity. When the direction of the angular velocity changes in time, this is a nontrivial problem involving coupled differential equations. Several possible approaches are examined, along with various improvements over previous efforts. These are then evaluated numerically by comparison to a complicated but analytically known rotation that is motivated by the important astrophysical...

  9. Achromatic orbital angular momentum generator

    OpenAIRE

    Bouchard, Frédéric; Mand, Harjaspreet; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of \\textit{two glued hollow axicons}, is used to introduce a nonuniform rotation of polarisation into a linearly polarised input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming be...

  10. Factors influencing perceived angular velocity

    Science.gov (United States)

    Kaiser, Mary K.; Calderone, Jack B.

    1991-01-01

    Angular velocity perception is examined for rotations both in depth and in the image plane and the influence of several object properties on this motion parameter is explored. Two major object properties are considered, namely, texture density which determines the rate of edge transitions for rotations in depth, i.e., the number of texture elements that pass an object's boundary per unit of time, and object size which determines the tangential linear velocities and 2D image velocities of texture elements for a given angular velocity. Results of experiments show that edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities had an impact on perceived angular velocity; this bias was associated with 2D image velocity rather than 3D tangential velocity. Despite these biases judgements were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter appeared to be good for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

  11. Synthesis, characterization and crystal structure determination of Mn (II) ion based 1D polymer constructed from 2, 2′ bipyridyl and azide group, its thermal stability, magnetic properties and Hirshfeld surface analysis

    International Nuclear Information System (INIS)

    The 1-D polymeric complex (I) is having formula [Mn(2,2′-BP).(N3)2]n, which has been crystallized in distilled water and characterized by elemental analyses, FT-IR spectrum, powder X-ray diffraction analyses and single-crystal diffraction analysis. This polymer possesses 1D helical chains or coils where Mn–azide–Mn forms the base of the coil which is alternatively garlanded by rigid bi-pyridine rings, where coordinates are in anti-fashion. The Mn (II) ions in the repeating units are linked by two end-on azide groups which extend through the two end-to-end azide ligands to the next unit forming a 1-D polymeric chain. The present study suggests that the use of this rigid and neutral building block leads to give better arrangement of the polymeric motif with [010] chains in 2-c uninodal net. During investigation of strong or weak intermolecular interactions, X-ray diffraction analysis and Hirshfeld surface analysis give rise to comparable results but in Hirshfeld surface analysis, two-third times more results of close contacts are obtained. The fingerprint plots demonstrate that these weak non-bonding interactions are important for stabilizing the crystal packing. Magnetic properties of the complex (I) were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of Mn (II) ions. The J-exchange parameters found are J1=64.3 K (45.3 cm−1), and J2=−75.7 K (−53.3 cm−1). Magnetic properties are discussed in comparison with those of other similar molecular magnets of [Mn(L–L)(N3)2]n type. - - Highlights: • Synthesized 1-D polymeric complex of Mn (II) ions with 2, 2′ bipyridyl and azide group. • X-ray data of complex (I) is in a good agreement with TGA and other spectroscopic techniques. • DFT calculations were done and compared with the parameter of experimental and theoretical data. • Intermolecular interactions calculated by Hirshfeld surface analysis compared with X-ray data

  12. Synthesis, characterization and crystal structure determination of Mn (II) ion based 1D polymer constructed from 2, 2′ bipyridyl and azide group, its thermal stability, magnetic properties and Hirshfeld surface analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mudsainiyan, R.K., E-mail: mudsainiyanrk@gmail.com; Jassal, Amanpreet Kaur; Chawla, S.K., E-mail: sukhvinder.k.chawla@gmail.com

    2015-05-15

    The 1-D polymeric complex (I) is having formula [Mn(2,2′-BP).(N{sub 3}){sub 2}]{sub n}, which has been crystallized in distilled water and characterized by elemental analyses, FT-IR spectrum, powder X-ray diffraction analyses and single-crystal diffraction analysis. This polymer possesses 1D helical chains or coils where Mn–azide–Mn forms the base of the coil which is alternatively garlanded by rigid bi-pyridine rings, where coordinates are in anti-fashion. The Mn (II) ions in the repeating units are linked by two end-on azide groups which extend through the two end-to-end azide ligands to the next unit forming a 1-D polymeric chain. The present study suggests that the use of this rigid and neutral building block leads to give better arrangement of the polymeric motif with [010] chains in 2-c uninodal net. During investigation of strong or weak intermolecular interactions, X-ray diffraction analysis and Hirshfeld surface analysis give rise to comparable results but in Hirshfeld surface analysis, two-third times more results of close contacts are obtained. The fingerprint plots demonstrate that these weak non-bonding interactions are important for stabilizing the crystal packing. Magnetic properties of the complex (I) were analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of Mn (II) ions. The J-exchange parameters found are J{sub 1}=64.3 K (45.3 cm{sup −1}), and J{sub 2}=−75.7 K (−53.3 cm{sup −1}). Magnetic properties are discussed in comparison with those of other similar molecular magnets of [Mn(L–L)(N{sub 3}){sub 2}]{sub n} type. - - Highlights: • Synthesized 1-D polymeric complex of Mn (II) ions with 2, 2′ bipyridyl and azide group. • X-ray data of complex (I) is in a good agreement with TGA and other spectroscopic techniques. • DFT calculations were done and compared with the parameter of experimental and theoretical data. • Intermolecular interactions calculated by Hirshfeld surface analysis

  13. Achromatic orbital angular momentum generator

    CERN Document Server

    Bouchard, Frédéric; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of \\textit{two glued hollow axicons}, is used to introduce a nonuniform rotation of polarisation into a linearly polarised input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarisation, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of $95\\%$ for these three different wavelengths is observed. %, which confirms its wavelen...

  14. Angular momentum in human walking.

    Science.gov (United States)

    Herr, Hugh; Popovic, Marko

    2008-02-01

    Angular momentum is a conserved physical quantity for isolated systems where no external moments act about a body's center of mass (CM). However, in the case of legged locomotion, where the body interacts with the environment (ground reaction forces), there is no a priori reason for this relationship to hold. A key hypothesis in this paper is that angular momentum is highly regulated throughout the walking cycle about all three spatial directions [|Lt| approximately 0], and therefore horizontal ground reaction forces and the center of pressure trajectory can be explained predominantly through an analysis that assumes zero net moment about the body's CM. Using a 16-segment human model and gait data for 10 study participants, we found that calculated zero-moment forces closely match experimental values (Rx2=0.91; Ry2=0.90). Additionally, the centroidal moment pivot (point where a line parallel to the ground reaction force, passing through the CM, intersects the ground) never leaves the ground support base, highlighting how closely the body regulates angular momentum. Principal component analysis was used to examine segmental contributions to whole-body angular momentum. We found that whole-body angular momentum is small, despite substantial segmental momenta, indicating large segment-to-segment cancellations ( approximately 95% medio-lateral, approximately 70% anterior-posterior and approximately 80% vertical). Specifically, we show that adjacent leg-segment momenta are balanced in the medio-lateral direction (left foot momentum cancels right foot momentum, etc.). Further, pelvis and abdomen momenta are balanced by leg, chest and head momenta in the anterior-posterior direction, and leg momentum is balanced by upper-body momentum in the vertical direction. Finally, we discuss the determinants of gait in the context of these segment-to-segment cancellations of angular momentum.

  15. Non-Colinearity of Angular Velocity and Angular Momentum

    Science.gov (United States)

    Burr, A. F.

    1974-01-01

    Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

  16. On the discriminating and stability increasing properties of Alizarin maroon in mixed-ligand complexes of Yttrium(3)

    International Nuclear Information System (INIS)

    The stability constants of the yttrium(3) mixed ligand complexes (1:1:1) containing alizarin maroon (azm) and as a second ligand salicylic acid (sa), 5-sulphosalicylic acid (ssa), 5-nitrosalicylic acid (nsa), 2,2'-bipyridyl (bipy) and 1,10-phenanthroline (phen) have been determined potentiometrically in 20% (v/v) ethanol-water medium (I 100 mmoldm-3 NaClO4, 25±0,10C). The complexation equilibria of the different biligand systems were demonstrated. All of these mixed-ligand complexes are considerably more stable than expected from purely statistical reasons. The results obtained were discussed in relation to the nature of the secondary ligands involved. For the equilibrium, Y(azm)2+Y(L)2 rightleftdblarrow 2Y(azm)(L), the following constants, log X, were determined: Y(azm)(sa) 3,11 (0,46); Y(azm)(ssa) 2,76 (0,33); Y(azm)(nsa) 3,02 (0,48); Y(azm)(bipy) 3,96 (0,99); Y(azm)(phen) 4,33 (1,07). The constants given in parentheses correspond to Δlog KY [log KY(azm)Y(azm)(L)-log KYY(L)]. (Author)

  17. Synthesis of New Ruthenium(Ⅱ)Bipyridyl Complexes and Studies on Their Photophysical and Photoelectrochemical Properties

    Institute of Scientific and Technical Information of China (English)

    宋林青; 刘普会; 王雪松; 侯原军; 张宝文; 曹怡; 李维盈; 张敬波; 肖绪瑞; 林原

    2003-01-01

    Two new mixed-ligand ruthenium(Ⅱ) complexes,Ru(dcbpy)-(LL)NCS)2[where dcbpy=4,4'-dicarboxyl-2,2''-bipyridine,LL=4,4'-bis(N-methyl-anilinomethyl)-2,2''-bipyridine(2)],were synthesized,and the tphotophysical properties of these complexes were studied.The metal-to-ligand charge transfer (MLCT) transitions of these complexes exhibited solvatochromic effect due to the existence of NCS ligands.The MLCT energies also strongly depend on the pH values of the solutions because of protonation and deprotonation of the carboxyl groups.The pKa values of the ground state,4.0 for 1 and 3.8 for 2,were obtained from the titration curves.The photoelectrochemical properties of 1 and 2 as sensitizers in sandwich-type solar cells have been studied.Complex 1 exhibited better photoelectrochemical behavior than complex 2 as expected.It was proved that the design of mixed-ligand complex by introducing electron donating group in one of the ligands should be a promising approach.

  18. Antioxidant activities of nano-bubble hydrogen-dissolved water assessed by ESR and 2,2′-bipyridyl methods

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Shinya [Laboratory of Cell-Death Control BioTechnology, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Nanatsuka 562, Shobara, Hiroshima 727-0023 (Japan); Radio Isotope Facilities for Medical Science, Life Science Research Center, Mie University, Edobashi 2-174, Tsu, Mie 514-8507 (Japan); Matsuoka, Daigo [− 600 mV Co., Ltd. Matsuhama-cho 2-4-1, Fukuyama, Hiroshima 720-0802 (Japan); Miwa, Nobuhiko, E-mail: miwa@butsuryo.ac.jp [Laboratory of Cell-Death Control BioTechnology, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Nanatsuka 562, Shobara, Hiroshima 727-0023 (Japan); Department of Radiological Technology, Faculty of Health Sciences, Butsuryo College of Osaka, Otorikitamachi 3-33, Nishi-ku, Sakai, Osaka 593-8328 (Japan)

    2015-08-01

    We prepared nano-bubble hydrogen-dissolved water (nano-H water) which contained hydrogen nano-bubbles of < 717-nm diameter for 54% of total bubbles. In the DMPO-spin trap electron spin resonance (ESR) method, the DMPO-OH:MnO ratio, being attributed to amounts of hydroxyl radicals (·OH), was 2.78 for pure water (dissolved hydrogen [DH] ≤ 0.01 ppm, oxidation-reduction potential [ORP] = + 324 mV), 2.73 for tap water (0.01 ppm, + 286 mV), 2.93 for commercially available hydrogen water (0.075 ppm, + 49 mV), and 2.66 for manufactured hydrogen water (0.788 ppm, − 614 mV), whereas the nano-H water (0.678 ppm, − 644 mV) exhibited 2.05, showing the superiority of nano-H water to other types of hydrogen water in terms of ·OH-scavenging activity. Then, the reduction activity of nano-H water was assessed spectrophotometrically by the 2,2′-bipyridyl method. Differential absorbance at 530 nm was in the order: 0.018 for pure water, 0.055 for tap water, 0.079 for nano-H water, 0.085 for commercially available hydrogen water, and 0.090 for manufactured hydrogen water, indicating a prominent reduction activity of hydrogen water and nano-H water against oxidation in ascorbate-coupled ferric ion–bipyridyl reaction. Thus, nano-H water has an improved antioxidant activity as compared to hydrogen water of similar DH-level, indicating the more marked importance of nano-bubbles rather than the concentration of hydrogen in terms of ·OH-scavenging. - Highlights: • We assessed the antioxidant activity of nano-bubble hydrogen-dissolved water (nano-H water). • Nano-H water exhibited superior ·OH-scavenging activity in DMPO-spin trap ESR. • A reduction ability of nano-H water was shown in 2,2′-bipyridyl reaction. • Nano-H water has an improved antioxidant activity as compared to hydrogen water of similar DH-level. • Results indicated the importance of nano-bubbles rather than the concentration of hydrogen.

  19. Olympic Wrestling and Angular Momentum.

    Science.gov (United States)

    Carle, Mark

    1988-01-01

    Reported is the use of a wrestling photograph in a noncalculus introductory physics course. The photograph presents a maneuver that could serve as an example for a discussion on equilibrium, forces, torque, and angular motion. Provided are some qualitative thoughts as well as quantitative calculations. (YP)

  20. Turbodrill rod angular velocity indicator

    Energy Technology Data Exchange (ETDEWEB)

    Rogachev, O.K.; Belozerova, L.P.; Konenkov, A.K.

    1984-01-01

    This paper outlines shortcomings of existing types of telemetry systems which resulted in production of the IChT-1 unit. Unit is intended for control of angular velocity of serially produced turbodrill rods, during drilling of wells up to 5000 m deep, and bottomhole temperatures to 100C. The paper provides a detailed description and diagrams for installing this unit.

  1. Metal-ligand cooperation.

    Science.gov (United States)

    Khusnutdinova, Julia R; Milstein, David

    2015-10-12

    Metal-ligand cooperation (MLC) has become an important concept in catalysis by transition metal complexes both in synthetic and biological systems. MLC implies that both the metal and the ligand are directly involved in bond activation processes, by contrast to "classical" transition metal catalysis where the ligand (e.g. phosphine) acts as a spectator, while all key transformations occur at the metal center. In this Review, we will discuss examples of MLC in which 1) both the metal and the ligand are chemically modified during bond activation and 2) bond activation results in immediate changes in the 1st coordination sphere involving the cooperating ligand, even if the reactive center at the ligand is not directly bound to the metal (e.g. via tautomerization). The role of MLC in enabling effective catalysis as well as in catalyst deactivation reactions will be discussed. PMID:26436516

  2. Syntheses, structures and properties of three metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiancai; Zhang, Yudong; Shang, Sensen; Li, Yanzhou; Chen, Lijuan, E-mail: ljchen@henu.edu.cn; Zhao, Junwei, E-mail: zhaojunwei@henu.edu.cn

    2015-01-15

    Three new metal–organic complexes Cu[Hbpdc]{sub 2} (1), [Ni(bpdc)(H{sub 2}O)]·H{sub 2}O (2) and [Ni(H{sub 2}bpdc)(H{sub 2}O){sub 2}]SO{sub 4} (3) (H{sub 2}bpdc=2,2′-bipyridyl-5,5′-dicarboxylic acid) have been hydrothermally prepared and structurally characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1 is a 3-D supramolecular architecture formed by hydrogen bonding interactions between carboxyl O atoms and strong face-to-face π⋯π stacking interactions between bipyridyl rings of Hbpdc{sup −} ligands, 2 exhibits an intriguing 2-D sheet constructed from [Ni(bpdc)(H{sub 2}O)] units and 3 displays an infinite 1-D chain built by ([Ni(H{sub 2}bpdc)(H{sub 2}O){sub 2}]{sup 2+}) fragments through SO{sub 4}{sup 2−}. Moreover, thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses of 3 have been conducted and the TG curve shows two-stage weight loss between 300 and 950 K and the corresponding apparent activation energies are calculated by Ozawa–Flynn–Wall (OFW) method and Friedman method. The most probable kinetic model function of the dehydration reaction of 3 has been estimated by Coats–Redfern integral method and Achar–Bridly–Sharp differential method. - Graphical abstract: Three metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands were synthesized and the thermal decomposition kinetics were investigated. - Highlights: • Metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands. • 3-D supramolecular architecture. • Thermal decomposition kinetics.

  3. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  4. Structure and spectroscopic properties of ruthenium(II) bipyridyl N-benzoyl-N'-(1,10-phenanthrolin-5-Yl)-thiourea

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Siew San [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Kassim, Mohammad B. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Ruthenium bipyridyl incorporating phenanthroline with thiourea molecules, [Ru(bpy){sub 2}(Phen-BT)](PF{sub 6}){sub 2}], has been synthesized and characterized by spectroscopic and electrochemical techniques. The infrared spectra of the complex shows the characteristics stretching frequencies for N-H at 3646 and 3585 cm{sup −1}, ν(C-N){sub phen} 1426 cm{sup −1}, ν(C=O) 1675 cm{sup −1}, ν(C=S) 1246 cm{sup −1}, ν(C-H){sub aromatic} 3353-3086 cm{sup −1}, ν(C-N){sub aliphatic} 1169-1026 cm{sup −1}, ν(C-H){sub bend} 764 cm{sup −1} and ν(PF{sub 6}{sup −}){sub free} 842 cm{sup −1}. The complex reveals two π→π* absorption bands at 237 (ε=26,302) and 286 nm (ε=36,848), which were assigned to the phenanthroline and bipyridyl moieties, respectively. A slightly broad and low energy band in the UV-vis spectrum at 450 nm (ε=7,209) of the complex was assigned to a MLCT transition. Besides, the complex also exhibits an emission band at 615 nm that arises from an excitation with a 440 nm light energy. The cyclic voltammetry of the complex shows an oxidation potential at +1.305 V vs. SCE that corresponds to the formal oxidation of Ru(II) to Ru(III)

  5. Functionalisation of bolaamphiphiles with mononuclear bis(2,2 '-bipyridyl)ruthenium(II) complexes for application in self assembled monolayers

    NARCIS (Netherlands)

    Killeen, JS; Browne, WR; Skupin, M; Fuhrhop, JH; Vos, JG

    2003-01-01

    A novel ruthenium(II) polypyridyl complex connected covalently to a bolaamphiphile, containing amide linkages to provide rigidity via hydrogen bonding in the monolayer, has been prepared. The ruthenium( II) complexes of this ligand and of the intermediates in the synthesis were prepared by modi. cat

  6. AngularJS test-driven development

    CERN Document Server

    Chaplin, Tim

    2015-01-01

    This book is for developers who want to learn about AngularJS development by applying testing techniques. You are assumed to have a basic knowledge and understanding of HTML, JavaScript, and AngularJS.

  7. Orbital angular momentum in phase space

    OpenAIRE

    Rigas, I.; Sanchez-Soto, L. L.; Klimov, A. B.; Rehacek, J.; Hradil, Z.

    2010-01-01

    A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented. Special attention is paid to the problems linked to rotational periodicity and angular-momentum discreteness.

  8. Phonons with orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Ayub, M. K. [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); National Centre for Physics, Shahdra Valley Road, Quaid-i-Azam University Campus, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics, Shahdra Valley Road, Quaid-i-Azam University Campus, Islamabad 44000 (Pakistan); Mendonca, J. T. [IPFN, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2011-10-15

    Ion accoustic waves or phonon modes are studied with orbital angular momentum (OAM) in an unmagnetized collissionless uniform plasma, whose constituents are the Boltzmann electrons and inertial ions. For this purpose, we have employed the fluid equations to obtain a paraxial equation in terms of ion density perturbations and discussed its Gaussian beam and Laguerre-Gauss (LG) beam solutions. Furthermore, an approximate solution for the electrostatic potential problem is presented, allowing to express the components of the electric field in terms of LG potential perturbations. The energy flux due to phonons is also calculated and the corresponding OAM is derived. Numerically, it is shown that the parameters such as azimuthal angle, radial and angular mode numbers, and beam waist, strongly modify the profiles of the phonon LG potential. The present results should be helpful in understanding the phonon mode excitations produced by Brillouin backscattering of laser beams in a uniform plasma.

  9. On Dunkl angular momenta algebra

    Science.gov (United States)

    Feigin, Misha; Hakobyan, Tigran

    2015-11-01

    We consider the quantum angular momentum generators, deformed by means of the Dunkl operators. Together with the reflection operators they generate a subalgebra in the rational Cherednik algebra associated with a finite real reflection group. We find all the defining relations of the algebra, which appear to be quadratic, and we show that the algebra is of Poincaré-Birkhoff-Witt (PBW) type. We show that this algebra contains the angular part of the Calogero-Moser Hamiltonian and that together with constants it generates the centre of the algebra. We also consider the gl( N ) version of the subalge-bra of the rational Cherednik algebra and show that it is a non-homogeneous quadratic algebra of PBW type as well. In this case the central generator can be identified with the usual Calogero-Moser Hamiltonian associated with the Coxeter group in the harmonic confinement.

  10. Angular momentum in QGP holography

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2014-10-01

    Full Text Available The quark chemical potential is one of the fundamental parameters describing the quark–gluon plasma produced by sufficiently energetic heavy-ion collisions. It is not large at the extremely high temperatures probed by the LHC, but it plays a key role in discussions of the beam energy scan programmes at the RHIC and other facilities. On the other hand, collisions at such energies typically (that is, in peripheral collisions give rise to very high values of the angular momentum density. Here we explain that holographic estimates of the quark chemical potential of a rotating sample of plasma can be very considerably improved by taking the angular momentum into account.

  11. The integration of angular velocity

    CERN Document Server

    Boyle, Michael

    2016-01-01

    A common problem in physics and engineering is determination of the orientation of an object given its angular velocity. When the direction of the angular velocity changes in time, this is a nontrivial problem involving coupled differential equations. Several possible approaches are examined, along with various improvements over previous efforts. These are then evaluated numerically by comparison to a complicated but analytically known rotation that is motivated by the important astrophysical problem of precessing black-hole binaries. It is shown that a straightforward solution directly using quaternions is most efficient and accurate, and that the norm of the quaternion is irrelevant. Integration of the generator of the rotation can also be made roughly as efficient as integration of the rotation. Both methods will typically be twice as efficient naive vector- or matrix-based methods. Implementation by means of standard general-purpose numerical integrators is stable and efficient, so that such problems can ...

  12. Integrating rotation from angular velocity

    OpenAIRE

    Zupan, Eva; Saje, Miran

    2011-01-01

    Abstract The integration of the rotation from a given angular velocity is often required in practice. The present paper explores how the choice of the parametrization of rotation, when employed in conjuction with different numerical time-integration schemes, effects the accuracy and the computational efficiency. Three rotation parametrizations – the rotational vector, the Argyris tangential vector and the rotational quaternion – are combined with three different numerical time-integration ...

  13. Orbital angular momentum is dependent on polarization

    OpenAIRE

    Li, Chun-Fang

    2009-01-01

    It is shown that the momentum density of free electromagnetic field splits into two parts. One has no contribution to the net momentum due to the transversality condition. The other yields all the momentum. The angular momentum that originates from the former part is spin, and the angular momentum that originates from the latter part is orbital angular momentum. Expressions for the spin and orbital angular momentum are given in terms of the electric vector in reciprocal space. The spin and or...

  14. Achromatic orbital angular momentum generator

    International Nuclear Information System (INIS)

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of two glued hollow axicons, is used to introduce a nonuniform rotation of polarization into a linearly polarized input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarization, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of 95% for these three different wavelengths is observed. This device may find applications in imaging from micro- to astronomical systems where a white vortex beam is needed. (paper)

  15. AngularJS web application development

    CERN Document Server

    Darwin, Peter Bacon

    2013-01-01

    The book will be a step-by-step guide showing the readers how to build a complete web app with AngularJSJavaScript developers who want to learn AngularJS for developing web apps. Knowledge of JavaScript and HTML is expected. No knowledge of AngularJS is required.

  16. Ligand modeling and design

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B.P. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    The purpose of this work is to develop and implement a molecular design basis for selecting organic ligands that would be used in the cost-effective removal of specific radionuclides from nuclear waste streams. Organic ligands with metal ion specificity are critical components in the development of solvent extraction and ion exchange processes that are highly selective for targeted radionuclides. The traditional approach to the development of such ligands involves lengthy programs of organic synthesis and testing, which in the absence of reliable methods for screening compounds before synthesis, results in wasted research effort. The author`s approach breaks down and simplifies this costly process with the aid of computer-based molecular modeling techniques. Commercial software for organic molecular modeling is being configured to examine the interactions between organic ligands and metal ions, yielding an inexpensive, commercially or readily available computational tool that can be used to predict the structures and energies of ligand-metal complexes. Users will be able to correlate the large body of existing experimental data on structure, solution binding affinity, and metal ion selectivity to develop structural design criteria. These criteria will provide a basis for selecting ligands that can be implemented in separations technologies through collaboration with other DOE national laboratories and private industry. The initial focus will be to select ether-based ligands that can be applied to the recovery and concentration of the alkali and alkaline earth metal ions including cesium, strontium, and radium.

  17. Dependency injection with AngularJS

    CERN Document Server

    Knol, Alex

    2013-01-01

    This book is a practical, hands-on approach to using dependency injection and implementing test-driven development using AngularJS. Dependency Injection with AngularJS is aimed at developers who are aware of AngularJS but need to get started with using it in real life applications. Also, developers who want to get into test-driven development with AngularJS can use this book as practical guide. Even if you know about dependency injection, it can serve as a good reference on how it is used within AngularJS. Readers are expected to have some experience with JavaScript.

  18. Matter waves with angular momentum

    CERN Document Server

    Bracher, C; Kleber, M; Bracher, Christian; Kramer, Tobias; Kleber, Manfred

    2003-01-01

    An alternative description of quantum scattering processes rests on inhomogeneous terms amended to the Schr\\"odinger equation. We detail the structure of sources that give rise to multipole scattering waves of definite angular momentum, and introduce pointlike multipole sources as their limiting case. Partial wave theory is recovered for freely propagating particles. We obtain novel results for ballistic scattering in an external uniform force field, where we provide analytical solutions for both the scattering waves and the integrated particle flux. As an illustration of the theory, we predict some properties of vortex-bearing atom laser beams outcoupled from a rotating Bose--Einstein condensate under the influence of gravity.

  19. Ligand modeling and design

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01

    The purpose of this work is to develop and implement a molecular design basis for selecting organic ligands that would be used tin applications for the cost-effective removal of specific radionuclides from nuclear waste streams.

  20. Controlling neutron orbital angular momentum.

    Science.gov (United States)

    Clark, Charles W; Barankov, Roman; Huber, Michael G; Arif, Muhammad; Cory, David G; Pushin, Dmitry A

    2015-09-24

    The quantized orbital angular momentum (OAM) of photons offers an additional degree of freedom and topological protection from noise. Photonic OAM states have therefore been exploited in various applications ranging from studies of quantum entanglement and quantum information science to imaging. The OAM states of electron beams have been shown to be similarly useful, for example in rotating nanoparticles and determining the chirality of crystals. However, although neutrons--as massive, penetrating and neutral particles--are important in materials characterization, quantum information and studies of the foundations of quantum mechanics, OAM control of neutrons has yet to be achieved. Here, we demonstrate OAM control of neutrons using macroscopic spiral phase plates that apply a 'twist' to an input neutron beam. The twisted neutron beams are analysed with neutron interferometry. Our techniques, applied to spatially incoherent beams, demonstrate both the addition of quantum angular momenta along the direction of propagation, effected by multiple spiral phase plates, and the conservation of topological charge with respect to uniform phase fluctuations. Neutron-based studies of quantum information science, the foundations of quantum mechanics, and scattering and imaging of magnetic, superconducting and chiral materials have until now been limited to three degrees of freedom: spin, path and energy. The optimization of OAM control, leading to well defined values of OAM, would provide an additional quantized degree of freedom for such studies. PMID:26399831

  1. The difficulty of measuring orbital angular momentum

    OpenAIRE

    Preece, D; Nieminen, T. A.; Asavei, T.; Heckenberg, N. R.; Rubinsztein-Dunlop, H.

    2011-01-01

    Light can carry angular momentum as well as energy and momentum; the transfer of this angular momentum to an object results in an optical torque. The development of a rotational analogue to the force measurement capability of optical tweezers is hampered by the difficulty of optical measurement of orbital angular momentum. We present an experiment with encouraging results, but emphasise the difficulty of the task.

  2. The difficulty of measuring orbital angular momentum

    Directory of Open Access Journals (Sweden)

    D. Preece

    2011-09-01

    Full Text Available Light can carry angular momentum as well as energy and momentum; the transfer of this angular momentum to an object results in an optical torque. The development of a rotational analogue to the force measurement capability of optical tweezers is hampered by the difficulty of optical measurement of orbital angular momentum. We present an experiment with encouraging results, but emphasise the difficulty of the task.

  3. Orbital angular momentum and the parton model

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliffe, P.G.

    1987-06-25

    The role of orbital angular momentum is discussed within the framework of the parton model. It is shown that a consistent interpretation of the Altarelli-Parisi equations governing the Q/sup 2/-evolution of helicity-weighted parton distributions necessitates the assumption that partons carry a large orbital angular momentum, contrary to popular belief. In developing the arguments presented, the Altarelli-Parisi formalism is extended to include orbital angular momentum dependence.

  4. Photoionization with Orbital Angular Momentum Beams

    OpenAIRE

    Picón, A.; Mompart, J.; de Aldana, J. R. Vázquez; Plaja, L.; Calvo, G. F.; Roso, L.

    2010-01-01

    Intense laser ionization expands Einstein's photoelectric effect rules giving a wealth of phenomena widely studied over the last decades. In all cases, so far, photons were assumed to carry one unit of angular momentum. However it is now clear that photons can possess extra angular momentum, the orbital angular momentum (OAM), related to their spatial profile. We show a complete description of photoionization by OAM photons, including new selection rules involving more than one unit of angula...

  5. Quantum formulation of fractional orbital angular momentum

    OpenAIRE

    Götte, Jörg B; Franke-Arnold, Sonja; Zambrini, Roberta; Barnett, Stephen M.

    2007-01-01

    The quantum theory of rotation angles (S. M. Barnett and D. T. Pegg, Phys. Rev. A, 41, 3427-3425 (1990)) is generalised to non-integer values of the orbital angular momentum. This requires the introduction of an additional parameter, the orientation of a phase discontinuity associated with fractional values of the orbital angular momentum. We apply our formalism to the propagation of light modes with fractional orbital angular momentum in the paraxial and non-paraxial regime.

  6. Orbital angular momentum induced beam shifts

    OpenAIRE

    Hermosa N.; Merano M.; Aiello A.; Woerdman J.P.

    2011-01-01

    We present experiments on Orbital Angular Momentum (OAM) induced beam shifts in optical reflection. Specifically, we observe the spatial Goos-H\\"anchen shift in which the beam is displaced parallel to the plane of incidence and the angular Imbert-Fedorov shift which is a transverse angular deviation from the geometric optics prediction. Experimental results agree well with our theoretical predictions. Both beam shifts increase with the OAM of the beam; we have measured these for OAM indices u...

  7. Oral candidiasis and angular cheilitis.

    Science.gov (United States)

    Sharon, Victoria; Fazel, Nasim

    2010-01-01

    Candidiasis, an often encountered oral disease, has been increasing in frequency. Most commonly caused by the overgrowth of Candida albicans, oral candidiasis can be divided into several categories including acute and chronic forms, and angular cheilitis. Risk factors for the development of oral candidiasis include immunosuppression, wearing of dentures, pharmacotherapeutics, smoking, infancy and old age, endocrine dysfunction, and decreased salivation. Oral candidiasis may be asymptomatic. More frequently, however, it is physically uncomfortable, and the patient may complain of burning mouth, dysgeusia, dysphagia, anorexia, and weight loss, leading to nutritional deficiency and impaired quality of life. A plethora of antifungal treatments are available. The overall prognosis of oral candidiasis is good, and rarely is the condition life threatening with invasive or recalcitrant disease.

  8. Magnetic Modulation of Stellar Angular Momentum Loss

    CERN Document Server

    Garraffo, Cecilia; Cohen, Ofer

    2014-01-01

    Angular Momentum Loss is important for understanding astrophysical phenomena such as stellar rotation, magnetic activity, close binaries, and cataclysmic variables. Magnetic breaking is the dominant mechanism in the spin down of young late-type stars. We have studied angular momentum loss as a function of stellar magnetic activity. We argue that the complexity of the field and its latitudinal distribution are crucial for angular momentum loss rates. In this work we discuss how angular momentum is modulated by magnetic cycles, and how stellar spin down is not just a simple function of large scale magnetic field strength.

  9. The Angular Momentum of the Solar System

    Science.gov (United States)

    Cang, Rongquin; Guo, Jianpo; Hu, Juanxiu; He, Chaoquiong

    2016-05-01

    The angular momentum of the Solar System is a very important physical quantity to the formation and evolution of the Solar System. Previously, the spin angular momentum of the Sun and the orbital angular momentum of the Eight Giant Planets were only taken into consideration, when researchers calculated the angular momentum of the Solar System. Nowadays, it seems narrow and conservative. Using Eggleton's code, we calculate the rotational inertia of the Sun. Furthermore, we obtain that the spin angular momentum of the Sun is 1.8838 x 10^41 kg m^2 s^-1. Besides the spin angular momentum of the Sun and the orbital angular momentum of the Eight Giant Planets, we also account for the orbital angular momentum of the Asteroid Belt, the Kuiper Belt, the Oort Cloud, the Ninth Giant Planet and the Solar Companion. We obtain that the angular momentum of the whole Solar System is 3.3212 x 10^45 kg m^2 s^-1.

  10. Transverse and longitudinal angular momenta of light

    International Nuclear Information System (INIS)

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin  angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin–direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties

  11. Flow injection chemiluminescence determination of cephalosporins in pharmaceutical preparations using tris (2,2'-bipyridyl) ruthenium (II)-potassium permanganate system

    International Nuclear Information System (INIS)

    A flow injection (FI) method using the tris(2,2'-bipyridyl) ruthenium(II) [Ru(bpy)32+]-potassium permanganate chemiluminescence(CL) was developed for the rapid and sensitive determination of cephalosporins such as cefoxitin, cefazolin, cephalexin, cefadroxil, cefaclor and cefoperazone. The method is based on the CL reaction of cephalosporins and Ru(bpy)32+ with potassium permanganate in the presence of perchloric acid, catalyzed by Mn(II). Under the optimum conditions, the calibration curves are linear over the range 0.10-12.0 μg ml-1 for cefoxitin, 0.10-10.0 μg ml-1 for cefoperazone and 0.10-15.0 μg ml-1 for cefazolin, cephalexin, cefadroxil, and cefaclor, respectively. The limits of detection (3σ) are 0.03 μg ml-1 for cefoxitin and cefadroxil, 0.06 μg ml-1 for cefoperazone and 0.08 μg ml-1 for cefazolin, cephalexin and cefaclor, respectively. The method was successfully applied to the determination of cefoxitin, cefazolin, cephalexin and cefadroxil in pharmaceutical formulations with a sample throughput of 90 h-1. There were no interference effects from some common excipients used in pharmaceutical preparations

  12. Influence of different ruthenium(II) bipyridyl complex on the photocatalytic H{sub 2} evolution over TiO{sub 2} nanoparticles with mesostructures

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Tianyou [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South-Central University for Nationalities, Wuhan 430074 (China); Ke, Dingning; Cai, Ping; Dai, Ke; Ma, Liang; Zan, Ling [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)

    2008-05-15

    H{sub 2} production over dye-sensitized Pt/TiO{sub 2} nanoparticles with mesostructures (m-TiO{sub 2}) under visible light ({lambda} > 420 nm) was investigated by using methanol as electron donors. Experimental results indicate that three types of ruthenium(II) bipyridyl complex dyes (one binuclear Ru, two mononuclear Ru), which can be attached to Pt/m-TiO{sub 2} with different linkage modes, show different photosensitization effects due to their different coordination circumstances and physicochemical properties. The dye tightly linked with m-TiO{sub 2} has better durability but the lowest H{sub 2} evolution efficiency, whereas the loosely attached dyes possess higher H{sub 2} evolution efficiency and preferable durability. It seems that the dynamic equilibrium between the linkage of the ground state dye with TiO{sub 2} and the divorce of the oxidization state dye from the surfaces plays a crucial role in the photochemical behavior during the photocatalyst sensitization process. It is helpful to improve the H{sub 2} evolution efficiency by enhancing the electron injection and hindering the backward transfer. The binuclear Ru(II) dye shows a better photosensitization in comparison with mononuclear Ru(II) dyes due to its large molecular area, conjugation system, and ''antenna effect'', which, in turn, improve the visible light harvesting and electron transfer between the dye molecules and TiO{sub 2}. (author)

  13. Flow injection chemiluminescence determination of cephalosporins in pharmaceutical preparations using tris (2,2'-bipyridyl) ruthenium (II)-potassium permanganate system

    Energy Technology Data Exchange (ETDEWEB)

    Thongpoon, Chalermporn [Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200 (Thailand); Liawruangrath, Boonsom [Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200 (Thailand); Liawruangrath, Saisunee [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wheatley, R. Alan [Department of Chemistry, University of Hull, Hull HU6 7RX (United Kingdom); Townshend, Alan [Department of Chemistry, University of Hull, Hull HU6 7RX (United Kingdom)]. E-mail: A.townshend@hull.ac.uk

    2005-11-30

    A flow injection (FI) method using the tris(2,2'-bipyridyl) ruthenium(II) [Ru(bpy){sub 3} {sup 2+}]-potassium permanganate chemiluminescence(CL) was developed for the rapid and sensitive determination of cephalosporins such as cefoxitin, cefazolin, cephalexin, cefadroxil, cefaclor and cefoperazone. The method is based on the CL reaction of cephalosporins and Ru(bpy){sub 3} {sup 2+} with potassium permanganate in the presence of perchloric acid, catalyzed by Mn(II). Under the optimum conditions, the calibration curves are linear over the range 0.10-12.0 {mu}g ml{sup -1} for cefoxitin, 0.10-10.0 {mu}g ml{sup -1} for cefoperazone and 0.10-15.0 {mu}g ml{sup -1} for cefazolin, cephalexin, cefadroxil, and cefaclor, respectively. The limits of detection (3{sigma}) are 0.03 {mu}g ml{sup -1} for cefoxitin and cefadroxil, 0.06 {mu}g ml{sup -1} for cefoperazone and 0.08 {mu}g ml{sup -1} for cefazolin, cephalexin and cefaclor, respectively. The method was successfully applied to the determination of cefoxitin, cefazolin, cephalexin and cefadroxil in pharmaceutical formulations with a sample throughput of 90 h{sup -1}. There were no interference effects from some common excipients used in pharmaceutical preparations.

  14. Electric response in the antiferroelectric crystal of 4,4′-di-t-butyl-2,2′-bipyridyl with chloranilic acid

    International Nuclear Information System (INIS)

    Highlights: • The semiconducting properties of the crystals were disclosed in the organic complex. • Dielectric relaxation and dc conductivity were investigated. • Activation energy for the thermally activated processes of the σdc was estimated. • The effect of hydrogen bonds on the mechanism of the phase transition and the electric properties of the crystal was discussed. - Abstract: The electric response was analyzed in the vicinity of the structural phase transition at 412 K in the single crystals of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP). The dielectric permittivity of the complex measured along the b direction between 300 and 440 K and at frequencies ranging from 500 Hz to 2 MHz indicates two phenomena. At low frequencies, dielectric losses are ascribed to the electric conductivity of the crystal, while at high frequencies, to the dielectric relaxation described by means of the Cole–Cole relationship. The parameters of the dielectric response: the relaxation time, τ, the dielectric increment, εο − ε∞, and the distribution parameter of the relaxation time, α, were estimated and analyzed. The low-temperature structure of the crystals indicates the antiferroelectric arrangement of the supramolecular hydrogen bonds. The dielectric results also presented for the deuterated crystals of dtBBP·CLA proved that the dynamics of protons in the hydrogen bonds are responsible for the mechanism of phase transition

  15. Electric response in the antiferroelectric crystal of 4,4‧-di-t-butyl-2,2‧-bipyridyl with chloranilic acid

    Science.gov (United States)

    Rok, M.; Piecha-Bisiorek, A.; Szklarz, P.; Bator, G.; Sobczyk, L.

    2015-05-01

    The electric response was analyzed in the vicinity of the structural phase transition at 412 K in the single crystals of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) with 4,4‧-di-t-butyl-2,2‧-bipyridyl (dtBBP). The dielectric permittivity of the complex measured along the b direction between 300 and 440 K and at frequencies ranging from 500 Hz to 2 MHz indicates two phenomena. At low frequencies, dielectric losses are ascribed to the electric conductivity of the crystal, while at high frequencies, to the dielectric relaxation described by means of the Cole-Cole relationship. The parameters of the dielectric response: the relaxation time, τ, the dielectric increment, εο - ε∞, and the distribution parameter of the relaxation time, α, were estimated and analyzed. The low-temperature structure of the crystals indicates the antiferroelectric arrangement of the supramolecular hydrogen bonds. The dielectric results also presented for the deuterated crystals of dtBBP·CLA proved that the dynamics of protons in the hydrogen bonds are responsible for the mechanism of phase transition.

  16. Palladium(II/Cationic 2,2’-Bipyridyl System as a Highly Efficient and Reusable Catalyst for the Mizoroki-Heck Reaction in Water

    Directory of Open Access Journals (Sweden)

    Fu-Yu Tsai

    2010-01-01

    Full Text Available A water-soluble and air-stable Pd(NH32Cl2/cationic 2,2’-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol % and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction “greener”.

  17. Electron transfer study on graphene modified glassy carbon substrate via electrochemical reduction and the application for tris(2,2'-bipyridyl)ruthenium(II) electrochemiluminescence sensor fabrication.

    Science.gov (United States)

    Xu, Yuanhong; Cao, Mengmei; Liu, Huihui; Zong, Xidan; Kong, Na; Zhang, Jizhen; Liu, Jingquan

    2015-07-01

    In this study, electron transfer behavior of the graphene nanosheets attachment on glassy carbon electrode (GCE) via direct electrochemical reduction of graphene oxide (GO) is investigated for the first time. The graphene modified electrode was achieved by simply dipping the GCE in GO suspension, followed by cyclic voltammetric scanning in the potential window from 0V to -1.5V. Tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)3(2+)] was immobilized on the graphene modified electrode and used as the redox probe to evaluate the electron transfer behavior. The electron transfer rate constant (Ks) was calculated to be 61.9±5.8s(-1), which is much faster than that of tiled graphene modified GCE (7.1±0.6s(-1)). The enhanced electron transfer property observed with the GCE modified by reductively deposited graphene is probably due to its standing configuration, which is beneficial to the electron transfer comparing with the tiled one. Because the abundant oxygen-containing groups are mainly located at the edges of GO, which should be much easier for the reduction to start from, the reduced GO should tend to stand on the electrode surface as evidenced by scanning electron microscopy analysis. In addition, due to the favored electron transfer and standing configuration, the Ru(bpy)3(2+) electrochemiluminescence sensor fabricated with standing graphene modified GCE provided much higher and more stable efficiency than that fabricated with tiled graphene.

  18. Angular momentum of non-paraxial light beam: Dependence of orbital angular momentum on polarization

    OpenAIRE

    Li, Chun-Fang

    2009-01-01

    It is shown that the momentum density of free electromagnetic field splits into two parts. One has no contribution to the net momentum due to the transversality condition. The other yields all the momentum. The angular momentum that is associated with the former part is spin, and the angular momentum that is associated with the latter part is orbital angular momentum. Expressions for the spin and orbital angular momentum are given in terms of the electric vector in reciprocal space. The spin ...

  19. Reactivity and molecular modeling of new solvatochromic mixed-ligand copper(II) chelates of 2-acetylbutyrolactone and dinitrogen bases.

    Science.gov (United States)

    Taha, A; Adly, Omima M I; Shebl, Magdy

    2015-04-01

    A new series of solvatochromic mononuclear mixed ligand chelates with the general formula: Cu(AcBL)(L)X; where AcBL=2-acetylbutyrolactonate, L=N,N,N',N'-tetramethylethylenediamine (Me4en), N,N,N',N'-tetramethylpropylene diamine (Me4pn), 1,10-phenanthroline (Phen) or 2,2'-bipyridyl (Bipy) and X=ClO4-, NO3- or Br- have been synthesized and characterized by the analytical and spectral methods, as well as magnetic and molar conductance measurements. The d-d absorption bands of Me4en-chelates as Nujol mulls or weak donor solvents solutions revealed square-planar, distorted octahedral and/or distorted trigonal bipyramid geometries for the perchlorate, nitrate and bromide chelates, respectively. However, an octahedral structure is identified for chelates in strong donor solvents. Perchlorate chelates show a remarkable color change from violet to green as the Lewis basicity of the donor solvent increases, whereas bromide chelates are mainly affected by the Lewis acidity of solvent. Specific and non-specific interactions of solvent molecules with the chelates were investigated on the basis of unified solvation model. Structural parameters of the free ligands and their Cu(II)-chelates have been calculated on the basis of semiempirical PM3 level and correlated with the experimental data.

  20. Radiofrequency encoded angular-resolved light scattering

    DEFF Research Database (Denmark)

    Buckley, Brandon W.; Akbari, Najva; Diebold, Eric D.;

    2015-01-01

    Encoded Angular-resolved Light Scattering (REALS), this technique multiplexes angular light scattering in the radiofrequency domain, such that a single photodetector captures the entire scattering spectrum from a particle over approximately 100 discrete incident angles on a single shot basis. As a proof...

  1. Angular-Rate Estimation Using Quaternion Measurements

    Science.gov (United States)

    Azor, Ruth; Bar-Itzhack, Y.; Deutschmann, Julie K.; Harman, Richard R.

    1998-01-01

    In most spacecraft (SC) there is a need to know the SC angular rate. Precise angular rate is required for attitude determination, and a coarse rate is needed for attitude control damping. Classically, angular rate information is obtained from gyro measurements. These days, there is a tendency to build smaller, lighter and cheaper SC, therefore the inclination now is to do away with gyros and use other means and methods to determine the angular rate. The latter is also needed even in gyro equipped satellites when performing high rate maneuvers whose angular-rate is out of range of the on board gyros or in case of gyro failure. There are several ways to obtain the angular rate in a gyro-less SC. When the attitude is known, one can differentiate the attitude in whatever parameters it is given and use the kinematics equation that connects the derivative of the attitude with the satellite angular-rate and compute the latter. Since SC usually utilize vector measurements for attitude determination, the differentiation of the attitude introduces a considerable noise component in the computed angular-rate vector.

  2. Exposing Library Services with AngularJS

    OpenAIRE

    Jakob Voß; Moritz Horn

    2014-01-01

    This article provides an introduction to the JavaScript framework AngularJS and specific AngularJS modules for accessing library services. It shows how information such as search suggestions, additional links, and availability can be embedded in any website. The ease of reuse may encourage more libraries to expose their services via standard APIs to allow usage in different contexts.

  3. Concepts of radial and angular kinetic energies

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Schleich, W.P.

    2002-01-01

    We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...

  4. Angular Momentum Eigenstates for Equivalent Electrons.

    Science.gov (United States)

    Tuttle, E. R.; Calvert, J. B.

    1981-01-01

    Simple and efficient methods for adding angular momenta and for finding angular momentum eigenstates for systems of equivalent electrons are developed. Several different common representations are used in specific examples. The material is suitable for a graduate course in quantum mechanics. (SK)

  5. Angular Momentum Distribution in the Transverse Plane

    CERN Document Server

    Adhikari, Lekha

    2016-01-01

    Several possibilities to relate the $t$-dependence of Generalized Parton Distributions (GPDs) to the distribution of angular momentum in the transverse plane are discussed. Using a simple spectator model we demonstrate that non of them correctly describes the orbital angular momentum distribution that for a longitudinally polarized nucleon obtained directly from light-front wavefunctions.

  6. Orbital Angular Momentum in the Nucleon

    OpenAIRE

    Garvey, Gerald T.

    2010-01-01

    Analysis of the measured value of the integrated \\bar{d}-\\bar{u} asymmetry (Ifas = 0.147+-0.027) in the nucleon show it to arise from nucleon fluctuations into baryon plus pion. Requiring angular momentum conservation in these fluctuations shows the associated orbital angular momentum is equal to the value of the flavor asymmetry.

  7. Detecting orbital angular momentum in radio signals

    OpenAIRE

    Then, H.; Thidé, B.; Mendonça, J T; Carozzi, T.D.; Bergman, J.; Baan, W. A.; Mohammadi, S. (Siawoosh); Eliasson, B.

    2008-01-01

    Electromagnetic waves with an azimuthal phase shift are known to have a well defined orbital angular momentum. Different methods that allow for the detection of the angular momentum are proposed. For some, we discuss the required experimental setup and explore the range of applicability.

  8. Responsive web design with AngularJS

    CERN Document Server

    Patel, Sandeep Kumar

    2014-01-01

    If you are an AngularJS developer who wants to learn about responsive web application development, this book is ideal for you. Responsive Web Design with AngularJS is intended for web developers or designers with a basic knowledge of HTML, CSS, and JavaScript.

  9. Angular momentum decomposition of Richardson's pairs

    International Nuclear Information System (INIS)

    The angular momentum decomposition of pairs obtained using Richardson's exact solution of the pairing Hamiltonian for the deformed 174Yb nucleus are displayed. The probabilities for low angular momenta of the collective pairs are strikingly different from the ones obtained in the BCS ground state

  10. AMPA receptor ligands

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian

    2004-01-01

    polyamines are known to modulate the function of these receptors in vivo. In this study, recent developments in the medicinal chemistry of polyamine-based ligands are given, particularly focusing on the use of solid-phase synthesis (SPS) as a tool for the facile generation of libraries of polyamine toxin...

  11. Does high harmonic generation conserve angular momentum?

    CERN Document Server

    Fleischer, Avner; Diskin, Tzvi; Sidorenko, Pavel; Cohen, Oren

    2013-01-01

    High harmonic generation (HHG) is a unique and useful process in which infrared or visible radiation is frequency up converted into the extreme ultraviolet and x ray spectral regions. As a parametric process, high harmonic generation should conserve the radiation energy, momentum and angular momentum. Indeed, conservation of energy and momentum have been demonstrated. Angular momentum of optical beams can be divided into two components: orbital and spin (polarization). Orbital angular momentum is assumed to be conserved and recently observed deviations were attributed to propagation effects. On the other hand, conservation of spin angular momentum has thus far never been studied, neither experimentally nor theoretically. Here, we present the first study on the role of spin angular momentum in extreme nonlinear optics by experimentally generating high harmonics of bi chromatic elliptically polarized pump beams that interact with isotropic media. While observing that the selection rules qualitatively correspond...

  12. Physical Angular Momentum Separation for QED

    CERN Document Server

    Sun, Weimin

    2016-01-01

    We study the non-uniqueness problem of the gauge-invariant angular momentum separation for the case of QED, which stems from the recent controversy concerning the proper definitions of the orbital angular momentum and spin operator of the individual parts of a gauge field system. For the free quantum electrodynamics without matter, we show that the basic requirement of Euclidean symmetry selects a unique physical angular momentum separation scheme from the multitude of the possible angular momentum separation schemes constructed using the various Gauge Invariant Extentions. Based on these results, we propose a set of natural angular momentum separation schemes for the case of interacting QED by invoking the formalism of asymptotic fields. Some perspectives on such a problem for the case of QCD are briefly discussed.

  13. Quark angular momentum in a spectator model

    International Nuclear Information System (INIS)

    We investigate the quark angular momentum in a model with the nucleon being a quark and a spectator. Both scalar and axial-vector spectators are included. We perform the calculations in the light-cone formalism where the parton concept is well defined. We calculate the quark helicity and canonical orbital angular momentum. Then we calculate the gravitational form factors which are often related to the kinetic angular momentums, and find that even in a no gauge field model we cannot identify the canonical angular momentums with half the sum of gravitational form factors. In addition, we examine the model relation between the orbital angular momentum and pretzelosity, and find it is violated in the axial-vector case

  14. Analysis of macromolecules, ligands and macromolecule-ligand complexes

    Science.gov (United States)

    Von Dreele, Robert B.

    2008-12-23

    A method for determining atomic level structures of macromolecule-ligand complexes through high-resolution powder diffraction analysis and a method for providing suitable microcrystalline powder for diffraction analysis are provided. In one embodiment, powder diffraction data is collected from samples of polycrystalline macromolecule and macromolecule-ligand complex and the refined structure of the macromolecule is used as an approximate model for a combined Rietveld and stereochemical restraint refinement of the macromolecule-ligand complex. A difference Fourier map is calculated and the ligand position and points of interaction between the atoms of the macromolecule and the atoms of the ligand can be deduced and visualized. A suitable polycrystalline sample of macromolecule-ligand complex can be produced by physically agitating a mixture of lyophilized macromolecule, ligand and a solvent.

  15. Angular momentum conservation for dynamical black holes

    OpenAIRE

    Hayward, Sean A.

    2006-01-01

    Angular momentum can be defined by rearranging the Komar surface integral in terms of a twist form, encoding the twisting around of space-time due to a rotating mass, and an axial vector. If the axial vector is a coordinate vector and has vanishing transverse divergence, it can be uniquely specified under certain generic conditions. Along a trapping horizon, a conservation law expresses the rate of change of angular momentum of a general black hole in terms of angular momentum densities of ma...

  16. Quartz angular rate sensor for automotive navigation

    Energy Technology Data Exchange (ETDEWEB)

    Nozoe, Toshiyuki; Ichinose, Toshihiko; Kawasaki, Syusaku; Hatanaka, Masakazu; Kuroda, Keisuke [Matsushita Electronic Components Co. Ltd. (Japan); Yamamoto, Kohji; Ogata, Motoki; Takeno, Shoichi [Fukui Matsushita Electric Co. Ltd. (Japan); Ishihara, Minoru; Ishii, Tadashi; Umeki, Mitoshi [Nihonn Denpa Kogyo Co. Ltd. (Japan)

    1999-07-01

    Many of the recent automotive navigation systems are introducing an angular rate sensor that detect vehicle yaw in their system due to the advantage of higher accuracy, in addition to a conventional GPS (Global Positioning System) and vehicle speed signals. Though there are a couple of other methods to get a vehicle direction information, the angular rate sensor is the most suitable device as a gyro in accuracy and reliability point of view. Matsushita developed a new compact angular rate sensor using quartz crystal for automotive navigation systems. The sensor's operation is based upon Coriolis force imposed on a vibrating quartz tuning fork. (orig.)

  17. Angular velocity: a new dimension in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, R.M.; Stephens, F.S.

    1984-08-09

    Nuclei can be studied from their ground states (approx.O(h/2..pi..)) up to angular momenta of order 100 (h/2..pi..), where they are literally pulled apart by centrifugal effects. This range of angular momenta can be viewed as resulting from cranking the nucleus around a rotation axis, where the critical variable is the cranking velocity. The calculated response of nuclei to such an imposed angular velocity corresponds well with recent observations, and includes a rich and varied interplay of collective and single-particle phenomena.

  18. Ligand-Receptor Interactions

    CERN Document Server

    Bongrand, Pierre

    2008-01-01

    The formation and dissociation of specific noncovalent interactions between a variety of macromolecules play a crucial role in the function of biological systems. During the last few years, three main lines of research led to a dramatic improvement of our understanding of these important phenomena. First, combination of genetic engineering and X ray cristallography made available a simultaneous knowledg of the precise structure and affinity of series or related ligand-receptor systems differing by a few well-defined atoms. Second, improvement of computer power and simulation techniques allowed extended exploration of the interaction of realistic macromolecules. Third, simultaneous development of a variety of techniques based on atomic force microscopy, hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or flexible transducers yielded direct experimental information of the behavior of single ligand receptor bonds. At the same time, investigation of well defined cellular models raised the ...

  19. Ligand exclusion on acetylcholinesterase.

    Science.gov (United States)

    Berman, H A; Leonard, K

    1990-11-27

    This paper examines covalent reactivity of AchE with respect to cationic and uncharged methylphosphonates and substrates in the absence and presence of cationic ligands selective for the active center and the peripheral anionic site. The organophosphorus inhibitors are enantiomeric alkyl methylphosphonothioates (1-5) containing cycloheptyl and isopropyl phosphono ester groups and S-methyl, S-n-pentyl, and S-[beta-(trimethylammonio)ethyl] leaving groups; these agents differ in their configuration about phosphorus and their steric, hydrophobic, and electrostatic characteristics. The synthetic substrates examined are acetylthiocholine, p-nitrophenyl acetate, and 7-acetoxy-4-methylcoumarin (7AMC). Antagonism of the methylphosphonothioate reaction by cationic ligands is strongly dependent on the nature of both the cation and the methylphosphonate but independent of the configuration about phosphorus. While all cations cause linear mixed inhibition of acetylthiocholine hydrolysis, there are observed a variety of inhibition patterns of 7AMC and p-nitrophenyl acetate hydrolysis that are distinctly nonlinear, as well as patterns in which the reciprocal plots intersect in the upper right quadrant. Strong antagonism of cationic (methylphosphonyl)thiocholines correlates very well with linear inhibition of acetylthiocholine. Ligands that cause only negligible antagonism of the uncharged methylphosphonates display nonlinear inhibition of uncharged substrates. These relationships, since they are most pronounced for peripheral site ligands and are strongly dependent on the charge carried by the reactant, suggest that the peripheral anionic site alters enzyme reactivity through an electrostatic interaction with the net negative active center. Such behavior indicates a potential role for the peripheral anionic site in conserving AchE catalytic efficiency within a narrow range of values. PMID:2271673

  20. Electrochemiluminescence of Tris(2,2'-bipyridyl)ruthenium(II) with Ascorbic Acid and Dehydroascorbic Acid in Aqueous and Non-aqueous Solutions.

    Science.gov (United States)

    Takahashi, Fumiki; Hattori, Kaoru; Matsuoka, Masanori; Jin, Jiye

    2016-01-01

    The electrochemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+)) is studied in non-aqueous media using dehydroascorbic acid (DHA) as coreactant to validate the evidence for the mechanism of the ascorbic acid (H2A)/Ru(bpy)3(2+) ECL system in an aqueous media. DHA is electrochemically reduced around -1.2 V vs. Ag/Ag(+) in pure acetonitrile to generate the ascorbyl radical anion (A(•-)), which is confirmed by in-situ UV-visible absorption measurements using a thin-layer spectroelectrochemical cell. The ECL of the DHA/Ru(bpy)3(2+) system in non-aqueous media is not observed in the potential range from 0 to +1.4 V in anodic potential sweep mode; however, distinct ECL is detected using double potential step electrolysis from -1.2 to +1.4 V vs. Ag/Ag(+). The ECL may be generated by a homogeneous charge-transfer process between A(•-) produced during the first pulse potential step (-1.2 V) and Ru(bpy)3(3+) generated during the second pulse potential step (+1.4 V). The calculated standard enthalpy (-ΔH°) for the charge-transfer reaction between A(•-) and Ru(bpy)3(3+) is 2.29 eV, which is larger than the lowest excited singlet state energy of Ru(bpy)3(2+) (*Ru(bpy)3(2+); 2.03 eV, 610 nm). It is determined that the generated intermediate A(•-) is crucial in the Ru(bpy)3(2+) ECL reaction. PMID:27063718

  1. Electric response in the antiferroelectric crystal of 4,4′-di-t-butyl-2,2′-bipyridyl with chloranilic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rok, M., E-mail: magdalena.rok@chem.uni.wroc.pl; Piecha-Bisiorek, A.; Szklarz, P.; Bator, G.; Sobczyk, L.

    2015-05-01

    Highlights: • The semiconducting properties of the crystals were disclosed in the organic complex. • Dielectric relaxation and dc conductivity were investigated. • Activation energy for the thermally activated processes of the σ{sub dc} was estimated. • The effect of hydrogen bonds on the mechanism of the phase transition and the electric properties of the crystal was discussed. - Abstract: The electric response was analyzed in the vicinity of the structural phase transition at 412 K in the single crystals of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP). The dielectric permittivity of the complex measured along the b direction between 300 and 440 K and at frequencies ranging from 500 Hz to 2 MHz indicates two phenomena. At low frequencies, dielectric losses are ascribed to the electric conductivity of the crystal, while at high frequencies, to the dielectric relaxation described by means of the Cole–Cole relationship. The parameters of the dielectric response: the relaxation time, τ, the dielectric increment, ε{sub ο} − ε{sub ∞}, and the distribution parameter of the relaxation time, α, were estimated and analyzed. The low-temperature structure of the crystals indicates the antiferroelectric arrangement of the supramolecular hydrogen bonds. The dielectric results also presented for the deuterated crystals of dtBBP·CLA proved that the dynamics of protons in the hydrogen bonds are responsible for the mechanism of phase transition.

  2. Angular Momentum Acquisition in Galaxy Halos

    CERN Document Server

    Stewart, Kyle R; Bullock, James S; Maller, Ariyeh H; Diemand, Juerg; Wadsley, James; Moustakas, Leonidas A

    2013-01-01

    We use high-resolution cosmological hydrodynamic simulations to study the angular momentum acquisition of gaseous halos around Milky Way sized galaxies. We find that cold mode accreted gas enters a galaxy halo with ~70% more specific angular momentum than dark matter averaged over cosmic time (though with a very large dispersion). In fact, we find that all matter has a higher spin parameter when measured at accretion than when averaged over the entire halo lifetime, and is well characterized by \\lambda~0.1, at accretion. Combined with the fact that cold flow gas spends a relatively short time (1-2 dynamical times) in the halo before sinking to the center, this naturally explains why cold flow halo gas has a specific angular momentum much higher than that of the halo and often forms "cold flow disks". We demonstrate that the higher angular momentum of cold flow gas is related to the fact that it tends to be accreted along filaments.

  3. Gravitational waves carrying orbital angular momentum

    CERN Document Server

    Bialynicki-Birula, Iwo

    2015-01-01

    Spinorial formalism is used to map every electromagnetic wave into the gravitational wave (within the linearized gravity). In this way we can obtain the gravitational counterparts of Bessel, Laguerre-Gauss, and other light beams carrying orbital angular momentum.

  4. The physics of angular momentum radio

    CERN Document Server

    Thidé, B; Then, H; Someda, C G; Ravanelli, R A

    2014-01-01

    Wireless communications, radio astronomy and other radio science applications are mainly implemented with techniques built on top of the electromagnetic linear momentum (Poynting vector) physical layer. As a supplement and/or alternative to this conventional approach, techniques rooted in the electromagnetic angular momentum physical layer have been advocated, and promising results from proof-of-concept radio communication experiments using angular momentum were recently published. This sparingly exploited physical observable describes the rotational (spinning and orbiting) physical properties of the electromagnetic fields and the rotational dynamics of the pertinent charge and current densities. In order to facilitate the exploitation of angular momentum techniques in real-world implementations, we present a systematic, comprehensive theoretical review of the fundamental physical properties of electromagnetic angular momentum observable. Starting from an overview that puts it into its physical context among ...

  5. Gravitational waves carrying orbital angular momentum

    Science.gov (United States)

    Bialynicki-Birula, Iwo; Bialynicka-Birula, Zofia

    2016-02-01

    Spinorial formalism is used to map every electromagnetic wave into the gravitational wave (within the linearized gravity). In this way we can obtain the gravitational counterparts of Bessel, Laguerre-Gauss, and other light beams carrying orbital angular momentum.

  6. Topological Orbital Angular Momentum Hall Current

    OpenAIRE

    Hu, Jiangping

    2005-01-01

    We show that there is a fundamental difference between spin Hall current and orbital angular momentum Hall current in Rashba- Dresselhaus spin orbit coupling systems. The orbital angular momentum Hall current has a pure topological contribution which is originated from the existence of magnetic flux in momentum space while there is no such topological nature for the spin Hall current. Moreover, we show that the orbital Hall conductance is always larger than the spin Hall conductance in the pr...

  7. ZKDR Distance, Angular Size and Phantom Cosmology

    OpenAIRE

    R.C. Santos; Lima, J. A. S.

    2006-01-01

    The influence of mass inhomogeneities on the angular size-redshift test is investigated for a large class of flat cosmological models driven by dark energy plus a cold dark matter component. The results are presented in two steps. First, the mass inhomogeneities are modeled by a generalized Zeldovich-Kantowski-Dyer-Roeder (ZKDR) distance which is characterized by a smoothness parameter $\\alpha(z)$ and a power index $\\gamma$, and, second, we provide a statistical analysis to angular size data ...

  8. Generalized Uncertainty Principle and Angular Momentum

    CERN Document Server

    Bosso, Pasquale

    2016-01-01

    Various models of quantum gravity suggest a modification of the Heisenberg's Uncertainty Principle, to the so-called Generalized Uncertainty Principle, between position and momentum. In this work we show how this modification influences the theory of angular momentum in Quantum Mechanics. In particular, we compute Planck scale corrections to angular momentum eigenvalues, the Hydrogen atom spectrum, the Stern-Gerlach experiment and the Clebsch-Gordan coefficients. We also examine effects of the Generalized Uncertainty Principle on multi-particle systems.

  9. Integrating rotation and angular velocity from curvature

    OpenAIRE

    Saje, Miran; Treven, Anita

    2016-01-01

    The problem of integrating the rotational vector from a given angular velocity vector is met in such diverse fields as the navigation, robotics, computer graphics, optical tracking and non-linear dynamics of flexible beams. For example, if the numerical formulation of non-linear dynamics of flexible beams is based on the interpolation of curvature, one needs to derive the rotation from the assumed curvature field. The relation between the angular velocity and the rotation is described by the ...

  10. Angular velocity nonlinear observer from vector measurements

    OpenAIRE

    Magnis, Lionel; Petit, Nicolas

    2015-01-01

    The paper proposes a technique to estimate the angular velocity of a rigid body from vector measurements. Compared to the approaches presented in the literature, it does not use attitude information nor rate gyros as inputs. Instead, vector measurements are directly filtered through a nonlinear observer estimating the angular velocity. Convergence is established using a detailed analysis of the linear-time varying dynamics appearing in the estimation error equation. This equation stems from t...

  11. Multipolar expansion of orbital angular momentum modes

    OpenAIRE

    Molina-Terriza, Gabriel

    2008-01-01

    In this letter a general method for expanding paraxial beams into multipolar electromagnetic fields is presented. This method is applied to the expansion of paraxial modes with orbital angular momentum (OAM), showing how the paraxial OAM is related to the general angular momentum of an electromagnetic wave. This method can be extended to quasi-paraxial beams, i.e. highly focused laser beams. Some applications to the control of electronic transitions in atoms are discussed.

  12. Orbital angular momentum in the nucleons

    OpenAIRE

    Lorcé, Cédric

    2014-01-01

    In the last decade, it has been realized that the orbital angular momentum of partons inside the nucleon plays a major role. It contributes significantly to nucleon properties and is at the origin of many asymmetries observed in spin physics. It is therefore of paramount importance to determine this quantity if we want to understand the nucleon internal structure and experimental observables. This triggered numerous discussions and controversies about the proper definition of orbital angular ...

  13. Orbital angular momentum of partially coherent beams

    OpenAIRE

    Serna Galán, Julio; Movilla Serrano, Jesús María

    2001-01-01

    The definition of the orbital angular momentum established for coherent beams is extended to partially coherent beams, expressed in terms of two elements of the beam matrix. This extension is justified by use of the Mercer expansion of partially coherent fields. General Gauss-Schell-model fields are considered, and the relation between the twist; parameter and the orbital angular momentum is analyzed. © 2001 Optical Society of America.

  14. Entanglement of Polarization and Orbital Angular Momentum

    OpenAIRE

    Bhatti, Daniel; von Zanthier, Joachim; Agarwal, Girish S.

    2015-01-01

    We investigate two-photon entangled states using two important degrees of freedom of the electromagnetic field, namely orbital angular momentum (OAM) and spin angular momentum. For photons propagating in the same direction we apply the idea of $\\textit{entanglement duality}$ and develop schemes to do $\\textit{entanglement sorting}$ based either on OAM or polarization. In each case the entanglement is tested using appropriate witnesses. We finally present generalizations of these ideas to thre...

  15. Radio beam vorticity and orbital angular momentum

    OpenAIRE

    Thidé, Bo; Tamburini, Fabrizio; Mari, Elettra; Romanato, Filippo; Barbieri, Cesare

    2011-01-01

    It has been known for a century that electromagnetic fields can transport not only energy and linear momentum but also angular momentum. However, it was not until twenty years ago, with the discovery in laser optics of experimental techniques for the generation, detection and manipulation of photons in well-defined, pure orbital angular momentum (OAM) states, that twisted light and its pertinent optical vorticity and phase singularities began to come into widespread use in science and technol...

  16. Pretzelosity TMD and Quark Orbital Angular Momentum

    OpenAIRE

    Lorce, Cédric; Pasquini, B.

    2015-01-01

    We study the connection between the quark orbital angular momentum and the pretzelosity transverse-momentum dependent parton distribution function. We discuss the origin of this relation in quark models, identifying as key ingredient for its validity the assumption of spherical symmetry for the nucleon in its rest frame. Finally we show that the individual quark contributions to the orbital angular momentum obtained from this relation can not be interpreted as the intrinsic contributions, but...

  17. Mastering AngularJD for .NET developers

    CERN Document Server

    Majid, Mohammad Wadood

    2015-01-01

    This book is envisioned for traditional developers and programmers who want to develop client-side applications using the AngularJS framework and ASP.NET Web API 2 with Visual Studio. .NET developers who have already built web applications or web services and who have a fundamental knowledge of HTML, JavaScript, and CSS and want to explore single-page applications will also find this guide useful. Basic knowledge of AngularJS would be helpful.

  18. Bexarotene ligand pharmaceuticals.

    Science.gov (United States)

    Hurst, R E

    2000-12-01

    Bexarotene (LGD-1069), from Ligand, was the first retinoid X receptor (RXR)-selective, antitumor retinoid to enter clinical trials. The company launched the drug for the treatment of cutaneous T-cell lymphoma (CTCL), as Targretin capsules, in the US in January 2000 [359023]. The company filed an NDA for Targretin capsules in June 1999, and for topical gel in December 1999 [329011], [349982] specifically for once-daily oral administration for the treatment of patients with early-stage CTCL who have not tolerated other therapies, patients with refractory or persistent early stage CTCL and patients with refractory advanced stage CTCL. The FDA approved Targretin capsules at the end of December 1999 for once-daily oral treatment of all stages of CTCL in patients refractory to at least one prior systemic therapy, at an initial dose of 300 mg/m2/day. After an NDA was submitted in December 1999 for Targretin gel, the drug received Priority Review status for use as a treatment of cutaneous lesions in patients with stage IA, IB or IIA CTCL [354836]. The FDA issued an approvable letter in June 2000, and granted marketing clearance for CTCL in the same month [370687], [372768], [372769], [373279]. Ligand had received Orphan Drug designation for this indication [329011]. At the request of the FDA, Ligand agreed to carry out certain post-approval phase IV and pharmacokinetic studies [351604]. The company filed an MAA with the EMEA for Targretin Capsules to treat lymphoma in November 1999 [348944]. The NDA for Targretin gel is based on a multicenter phase III trial that was conducted in the US, Canada, Europe and Australia involving 50 patients and a multicenter phase I/II clinical program involving 67 patients. Targretin gel was evaluated for the treatment of patients with early stage CTCL (IA-IIA) who were refractory to, intolerant to, or reached a response plateau for at least 6 months on at least two prior therapies. Efficacy results exceeded the protocol-defined response

  19. A novel solid-state electrochemiluminescence detector for capillary electrophoresis based on tris(2,2'-bipyridyl)ruthenium(II) immobilized in Nafion/PTC-NH2 composite film.

    Science.gov (United States)

    Liu, Huijing; Yuan, Ruo; Chai, Yaqing; Mao, Li; Yang, Xia; Zhuo, Ying; Yuan, Yali

    2011-04-15

    A new electrochemiluminescence (ECL) detector for capillary electrophoresis (CE) based on tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) immobilized in Nafion/PTC-NH(2) (an ammonolysis product of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)) composite film was presented for the first time. The Nafion/PTC-NH(2) composite film could effectively immobilize tris(2,2'-bipyridyl)ruthenium(II) via ion-exchange and electrostatic interaction. Cyclic voltammetric and ECL behavior of Nafion/PTC-NH(2)/Ru composite film was investigated compared to Nafion/Ru composite. The Nafion/PTC-NH(2)/Ru composite film exhibited good ECL stability and simple operability. Then the CE with solid-state ECL detector system was successfully used to detect sophora - a quinolizidine type - alkaloids as sophoridine (SR) and matrine (MT). The CE-ECL parameters that affected separation and detection were optimized. Under the optimized conditions, the linear range was from 2.5 × 10(-8) to 2 × 10(-6)mol/L for SR, 1.0 × 10(-8) to 1.0 × 10(-6)mol/L for MT. The detection limit (S/N=3) was estimated to be 5 × 10(-9) and 10(-9)mol/L for SR and MT, respectively. It was shown that the CE coupling with solid-state ECL detector system exhibited satisfying sensitivity of analysis. PMID:21376962

  20. Molecular path for ligand search

    Institute of Scientific and Technical Information of China (English)

    Tao Lu; Yuan Yuan Qiao; Pan Wen Shen

    2011-01-01

    A ligand is a small molecule bind to several residues of a receptor. We adapt the concept of molecular path for effective ligand search with its contacting residues. Additionally, we allow wild type definitions on atoms and bonds of molecular paths for fuzzy algorithms on structural match. We choose hydrogen bond interactions to characterize the binding mode of a ligand by several proper molecular paths and use them to query the deposited ligands in PDBe that interact with their residues in the same way. Expression of molecular path and format of database entries are described with examples. Our molecular path provides a new approach to explore the ligand-receptor interactions and to provide structural framework reference on new ligand design.

  1. Macrocyclic G-quadruplex ligands

    DEFF Research Database (Denmark)

    Nielsen, M C; Ulven, Trond

    2010-01-01

    G-quadruplex stabilizing compounds have recently received increased interest due to their potential application as anticancer therapeutics. A significant number of structurally diverse G-quadruplex ligands have been developed. Some of the most potent and selective ligands currently known are...... macrocyclic structures which have been modeled after the natural product telomestatin or from porphyrin-based ligands discovered in the late 1990s. These two structural classes of G-quadruplex ligands are reviewed here with special attention to selectivity and structure-activity relationships, and with focus...

  2. Ultrafast angular momentum transfer in multisublattice ferrimagnets.

    Science.gov (United States)

    Bergeard, N; López-Flores, V; Halté, V; Hehn, M; Stamm, C; Pontius, N; Beaurepaire, E; Boeglin, C

    2014-03-11

    Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. However, one of the unsolved questions is that of conservation of the total angular momentum during the ultrafast demagnetization. Here we report the ultrafast transfer of angular momentum during the first hundred femtoseconds in ferrimagnetic Co0.8Gd0.2 and Co0.74Tb0.26 films. Using time-resolved X-ray magnetic circular dichroism allowed for time-resolved determination of spin and orbital momenta for each element. We report an ultrafast quenching of the magnetocrystalline anisotropy and show that at early times the demagnetization in ferrimagnetic alloys is driven by the local transfer of angular momenta between the two exchange-coupled sublattices while the total angular momentum stays constant. In Co0.74Tb0.26 we have observed a transfer of the total angular momentum to an external bath, which is delayed by ~150 fs.

  3. An orbital angular momentum spectrometer for electrons

    Science.gov (United States)

    Harvey, Tyler; Grillo, Vincenzo; McMorran, Benjamin

    2016-05-01

    With the advent of techniques for preparation of free-electron and neutron orbital angular momentum (OAM) states, a basic follow-up question emerges: how do we measure the orbital angular momentum state distribution in matter waves? Control of both the energy and helicity of light has produced a range of spectroscopic applications, including molecular fingerprinting and magnetization mapping. Realization of an analogous dual energy-OAM spectroscopy with matter waves demands control of both initial and final energy and orbital angular momentum states: unlike for photons, final state post-selection is necessary for particles that cannot be annihilated. We propose a magnetic field-based mechanism for quantum non-demolition measurement of electron OAM. We show that OAM-dependent lensing is produced by an operator of form U =exp iLzρ2/ℏb2 where ρ =√{x2 +y2 } is the radial position operator, Lz is the orbital angular momentum operator along z, and b is the OAM dispersion length. We can physically realize this operator as a term in the time evolution of an electron in magnetic round lens. We discuss prospects and practical challenges for implementation of a lensing orbital angular momentum measurement. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under the Early Career Research Program Award # DE-SC0010466.

  4. Angular distribution of oriented nucleus fission neutrons

    International Nuclear Information System (INIS)

    Calculations of anisotropy of angular distribution of oriented 235U nuclei thermal fission neutrons have been carried out. the neutrons were assumed to evaporate isotropically by completely accelerated fragements in the fragment system with only its small part, i. e. fission-producing neutrons, emitted at the moment of neck break. It has been found out that at low energies of neutrons Esub(n)=1-2 MeV the sensitivity of the angular distribution anisotropy to variations of spectrum of neutron evaporation from fragments and the magnitude of a share of fission-producing neutrons reaches approximately 100%, which at high energies, Esub(n) > 5 MeV it does not exceed approximately 20%. Therefore the angular distribution of fast neutrons to a greater degree of confidence may be used for restoring the angular distribution anisotropy of fragments while the angular distribution of low energy neutrons may be used for deriving information on the fission process, but only in case 6f the experiment accuracy is better than approximately 3%

  5. Dirac Green function for angular projection potentials

    Science.gov (United States)

    Zeller, Rudolf

    2015-11-01

    The aim of this paper is twofold: first, it is shown that the angular dependence of the Dirac Green function can be described analytically for potentials with non-local dependence on the angular variables if they are chosen as projection potentials in angular momentum space. Because the local dependence on the radial variable can be treated to any precision with present computing capabilities, this means that the Green function can be calculated practically exactly. Second, it is shown that a result of this kind not only holds for a single angular projection potential but also more generally, for instance if space is divided into non-overlapping cells and a separate angular projection potential is used in each cell. This opens the way for relativistic density-functional calculations within a different perspective than the conventional one. Instead of trying to obtain the density for a given potential approximately as well as possible, the density is determined exactly for non-local potentials which can approximate arbitrary local potentials as well as desired.

  6. Data-oriented development with AngularJS

    CERN Document Server

    Waikar, Manoj

    2015-01-01

    This book helps beginner-level AngularJS developers organize AngularJS applications by discussing important AngularJS concepts and best practices. If you are an experienced AngularJS developer but haven't written directives or haven't created custom HTML controls before, then this book is ideal for you.

  7. Variation in Angular Velocity and Angular Acceleration of a Particle in Rectilinear Motion

    Science.gov (United States)

    Mashood, K. K.; Singh, V. A.

    2012-01-01

    We discuss the angular velocity ([image omitted]) and angular acceleration ([image omitted]) associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a…

  8. Hydroxyl radical-related electrogenerated chemiluminescence reaction for a ruthenium tris(2,2')bipyridyl/co-reactants system at boron-doped diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, K. [Department of Chemistry and Earth Sciences, Faculty of Science Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan)]. E-mail: khonda@yamaguchi-u.ac.jp; Yamaguchi, Y. [Department of Chemistry and Earth Sciences, Faculty of Science Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Yamanaka, Y. [Department of Chemistry and Earth Sciences, Faculty of Science Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Yoshimatsu, M. [Department of Chemistry and Earth Sciences, Faculty of Science Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Fukuda, Y. [Department of Chemistry and Earth Sciences, Faculty of Science Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Fujishima, A. [Kanagawa Academy of Science and Technology (KAST), 3-2-1, Sakato, Takastu-ku, Kawasaki-shi, Kanagawa 213-0012 (Japan)

    2005-11-01

    An electrogenerated chemiluminescence (ECL) reaction of the Ru(bpy){sub 3} {sup 2+} (2,2'-bipyridyl, bpy)/co-reactant system in the extremely high-potential region (over 2.6 V versus Ag/AgCl) was probed using a boron-doped diamond (BDD) electrode. At the BDD electrode, three ECL waves (1.25, 2.30 and 3.72 V) were observed in cyclic voltammograms for 20 mM ascorbic acid (AA). For the ECL peaks observed at 1.25 V corresponding to the oxidation potential for Ru(bpy){sub 3} {sup 2+} (1.15 V), the light intensities and current densities were found to depend on the square root of the AA concentration. This suggests that AA oxidation, followed by the formation of the reducing radical that is necessary for generating the excited state of Ru(bpy){sub 3} {sup 2+*} occurred through homogeneous electron-transfer between Ru(bpy){sub 3} {sup 3+} and the AA species. However, for the ECL peaks at 2.30 V, the current densities and light intensities linearly increased with increasing AA concentration, suggesting that the reducing radical was formed through the direct oxidation at the electrode surface. The ECL reaction at 3.72 V was observed only at the BDD electrode and not at other electrodes. The onset potentials for the light intensity were approximately 2.6 V, independently of the type of the co-reactants (e.g. 2-propanol and AA). The peak potentials exhibited linear relation with the co-reactant concentration. In the analysis of the ECL intensity for various co-reactants (alcohols) that show different reactivity for the hydrogen abstraction reaction, the order of the light intensities at the peaks for alcohols was found to be consistent with that for the rate constants of the hydrogen abstraction reaction. These results indicate that the co-reactant radical was formed through the hydrogen abstraction reaction with the hydroxyl radical (HO{center_dot}) generated during the oxygen evolution reaction.

  9. Physics from Angular Projection of Rectangular Grids

    CERN Document Server

    Singh, Ashmeet

    2015-01-01

    In this paper, we present a mathematical model for the angular projection of a rectangular arrangement of points in a grid. This simple, yet interesting problem, has both a scholarly value and applications for data extraction techniques to study the physics of various systems. Our work can interest undergraduate students to understand subtle points in the angular projection of a grid and describes various quantities of interest in the projection with completeness and sufficient rigour. We show that for certain angular ranges, the projection has non-distinctness, and calculate the details of such angles, and correspondingly, the number of distinct points and the total projected length. We focus on interesting trends obtained for the projected length of the grid elements and present a simple application of the model to determine the geometry of an unknown grid whose spatial extensions are known, using measurement of the grid projection at two angles only. Towards the end, our model is shown to have potential ap...

  10. Chirality and angular momentum in optical radiation

    CERN Document Server

    Coles, Matt M

    2012-01-01

    This paper develops, in precise quantum electrodynamic terms, photonic attributes of the "optical chirality density", one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive "superchiral" phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multi-mode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin angular momentum of light is engaged in such...

  11. Angular momentum transfer in incomplete fusion

    Indian Academy of Sciences (India)

    B S Tomar; K Surendra Babu; K Sudarshan; R Tripathi; A Goswami

    2005-02-01

    Isomeric cross-section ratios of evaporation residues formed in 12C+93Nb and 16O + 89Y reactions were measured by recoil catcher technique followed by off-line -ray spectrometry in the beam energy range of 55.7-77.5 MeV for 12C and 68-81 MeV for 16O. The isomeric cross-section ratios were resolved into that for complete and incomplete fusion reactions. The angular momentum of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross-section ratio by considering the statistical de-excitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with angular momenta slightly smaller than critical angular momentum for complete fusion, indicating the deeper interpenetration of projectile and target nuclei than that in peripheral collisions.

  12. Radio beam vorticity and orbital angular momentum

    CERN Document Server

    Thidé, Bo; Mari, Elettra; Romanato, Filippo; Barbieri, Cesare

    2011-01-01

    It has been known for a century that electromagnetic fields can transport not only energy and linear momentum but also angular momentum. However, it was not until twenty years ago, with the discovery in laser optics of experimental techniques for the generation, detection and manipulation of photons in well-defined, pure orbital angular momentum (OAM) states, that twisted light and its pertinent optical vorticity and phase singularities began to come into widespread use in science and technology. We have now shown experimentally how OAM and vorticity can be readily imparted onto radio beams. Our results extend those of earlier experiments on angular momentum and vorticity in radio in that we used a single antenna and reflector to directly generate twisted radio beams and verified that their topological properties agree with theoretical predictions. This opens the possibility to work with photon OAM at frequencies low enough to allow the use of antennas and digital signal processing, thus enabling software con...

  13. Surface angular momentum of light beams.

    Science.gov (United States)

    Ornigotti, Marco; Aiello, Andrea

    2014-03-24

    Traditionally, the angular momentum of light is calculated for "bullet-like" electromagnetic wave packets, although in actual optical experiments "pencil-like" beams of light are more commonly used. The fact that a wave packet is bounded transversely and longitudinally while a beam has, in principle, an infinite extent along the direction of propagation, renders incomplete the textbook calculation of the spin/orbital separation of the angular momentum of a light beam. In this work we demonstrate that a novel, extra surface part must be added in order to preserve the gauge invariance of the optical angular momentum per unit length. The impact of this extra term is quantified by means of two examples: a Laguerre-Gaussian and a Bessel beam, both circularly polarized.

  14. Quark orbital angular momentum from lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, N.; Dong, S. J.; Liu, K. F.; Mankiewicz, L.; Mukhopadhyay, N. C.

    2000-12-01

    We calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice with the quenched approximation. The disconnected insertion is estimated stochastically which employs the Z{sub 2} noise with an unbiased subtraction. This reduced the error by a factor of 3--4 with negligible overhead. The total quark contribution to the proton spin is found to be 0.30{+-}0.07. From this and the quark spin content we deduce the quark orbital angular momentum to be 0.17{+-}0.06 which is {approx}34% of the proton spin. We further predict that the gluon angular momentum is 0.20{+-}0.07; i.e., {approx}40% of the proton spin is due to the glue.

  15. Quark orbital angular momentum from lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, K.F.

    2000-01-10

    The authors calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice. The disconnected insertion is estimated stochastically which employs the Z{sub 2} noise with an unbiased subtraction. This reduced the error by a factor of 4 with negligible overhead. The total quark contribution to the proton spin is found to be 0.30{+-}0.07. From this and the quark spin content the authors deduce the quark orbital angular momentum to be 0.17{+-}0.06 which is {approximately} 34% of the proton spin. The authors further predict that the gluon angular momentum to be 0.20{+-}0.07, i. e. {approximately} 40% of the proton spin is due to the glue.

  16. Ghost Imaging Using Orbital Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    赵生妹; 丁建; 董小亮; 郑宝玉

    2011-01-01

    We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum. In the signal arm, object spatial information is encoded as a phase matrix. For an N-grey-scale object, different phase matrices, varying from 0 to K with increment n/N, are used for different greyscales, and then they are modulated to a signal beam by a spatial light modulator. According to the conservation of the orbital angular momentum in the ghost imaging system, these changes will give different coincidence rates in measurement, and hence the object information can be extracted in the idler arm. By simulations and experiments, the results show that our scheme can improve the resolution of the image effectively. Compared with another encoding method using orbital angular momentum, our scheme has a better performance for both characters and the image object.%We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum.In the signal arm,object spatial information is encoded as a phase matrix.For an N-grey-scale object,different phase matrices,varying from 0 to π with increment π/N,are used for different greyscales,and then they are modulated to a signal beam by a spatial light modulator.According to the conservation of the orbital angular momentum in the ghost imaging system,these changes will give different coincidence rates in measurement,and hence the object information can be extracted in the idler arm.By simulations and experiments,the results show that our scheme can improve the resolution of the image effectively.Compared with another encoding method using orbital angular momentum,our scheme has a better performance for both characters and the image object.

  17. Angular momentum and the electromagnetic top

    Indian Academy of Sciences (India)

    GIANFRANCO SPAVIERI; GEORGE T GILLIES

    2016-08-01

    The electric charge–magnetic dipole interaction is considered. If $\\Gamma_{\\rm em}$ is the electromagnetic and $\\Gamma_{\\rm mech}$ the mechanical angular momentum, the conservation law for the total angular momentum $\\Gamma_{\\rm tot}$ holds: $\\Gamma_{\\rm tot}$ =$\\Gamma_{\\rm em}$ + $\\Gamma_{\\rm mech}$ = ${\\rm const.}$, but when the dipole moment varies with time, $\\Gamma_{\\rm mech}$ is not conserved. We show that the non-conserved $\\Gamma_{\\rm mech}$ of such a macroscopic isolated system might be experimentally observable. With advanced technology, the strength of the interaction hints to the possibility of novel applications for gyroscopes, such as the electromagnetic top.

  18. Time-resolved orbital angular momentum spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Noyan, Mehmet A.; Kikkawa, James M. [Department of Physics and Astronomy, The University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-07-20

    We introduce pump-probe magneto-orbital spectroscopy, wherein Laguerre-Gauss optical pump pulses impart orbital angular momentum to the electronic states of a material and subsequent dynamics are studied with 100 fs time resolution. The excitation uses vortex modes that distribute angular momentum over a macroscopic area determined by the spot size, and the optical probe studies the chiral imbalance of vortex modes reflected off the sample. First observations in bulk GaAs yield transients that evolve on time scales distinctly different from population and spin relaxation, as expected, but with surprisingly large lifetimes.

  19. Time-resolved orbital angular momentum spectroscopy

    International Nuclear Information System (INIS)

    We introduce pump-probe magneto-orbital spectroscopy, wherein Laguerre-Gauss optical pump pulses impart orbital angular momentum to the electronic states of a material and subsequent dynamics are studied with 100 fs time resolution. The excitation uses vortex modes that distribute angular momentum over a macroscopic area determined by the spot size, and the optical probe studies the chiral imbalance of vortex modes reflected off the sample. First observations in bulk GaAs yield transients that evolve on time scales distinctly different from population and spin relaxation, as expected, but with surprisingly large lifetimes

  20. Wilson lines and orbital angular momentum

    International Nuclear Information System (INIS)

    We present an explicit realization of the Chen et al. approach to the proton spin decomposition in terms of Wilson lines, generalizing the light-front gauge-invariant extensions discussed recently by Hatta. Particular attention is drawn to the residual gauge freedom by further separating the pure-gauge term into contour and residual terms. We show that the kinetic orbital angular momentum operator can be expressed in terms of the Wigner operator only when the momentum variable is integrated over. Finally, we confirm from twist-2 arguments that the advanced, retarded and antisymmetric light-front canonical orbital angular momenta are the same

  1. Quark Orbital Angular Momentum from Lattice QCD

    OpenAIRE

    N. Mathur; Dong, S. J.; Liu, K. F.; Mankiewicz, L.; Mukhopadhyay, N. C.

    1999-01-01

    We calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice. The disconnected insertion is estimated stochastically which employs the $Z_2$ noise with an unbiased subtraction. This reduced the error by a factor of 4 with negligible overhead. The total quark contribution to the proton spin is found to be $0.30 \\pm 0.07$. From this and the quark spin content we deduce the quark orbital angular momentum to be $0.17 \\pm 0.06$ wh...

  2. Wilson lines and orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Lorcé, Cédric, E-mail: cedric.lorce@googlemail.com [IPNO, Université Paris-Sud, CNRS/IN2P3, 91406 Orsay (France); LPT, Université Paris-Sud, CNRS, 91406 Orsay (France)

    2013-02-12

    We present an explicit realization of the Chen et al. approach to the proton spin decomposition in terms of Wilson lines, generalizing the light-front gauge-invariant extensions discussed recently by Hatta. Particular attention is drawn to the residual gauge freedom by further separating the pure-gauge term into contour and residual terms. We show that the kinetic orbital angular momentum operator can be expressed in terms of the Wigner operator only when the momentum variable is integrated over. Finally, we confirm from twist-2 arguments that the advanced, retarded and antisymmetric light-front canonical orbital angular momenta are the same.

  3. On the vector model of angular momentum

    Science.gov (United States)

    Saari, Peeter

    2016-09-01

    Instead of (or in addition to) the common vector diagram with cones, we propose to visualize the peculiarities of quantum mechanical angular momentum by a completely quantized 3D model. It spotlights the discrete eigenvalues and noncommutativity of components of angular momentum and corresponds to outcomes of measurements—real or computer-simulated. The latter can be easily realized by an interactive worksheet of a suitable program package of algebraic calculations. The proposed complementary method of visualization helps undergraduate students to better understand the counterintuitive properties of this quantum mechanical observable.

  4. Ruthenium bistridentate complexes with non-symmetrical hexahydro-pyrimidopyrimidine ligands: a structural and theoretical investigation of their optical and electrochemical properties.

    Science.gov (United States)

    Laramée-Milette, Baptiste; Hanan, Garry S

    2016-08-01

    Six ruthenium complexes were synthesized based on three non-symmetrical tridentate ligands bearing the strongly electron-donating group 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-α]pyrimidine (hpp), bpyG (bpyG = 2,2'-bipyridyl-6-hpp), phenG (phenG = 2-hpp-1,10-phenanthroline) and QpyG (QpyG = 2-hpp-6-quinolylpyridyl). The fac-/mer-conformation of the homoleptic species has a dramatic effect on the optical properties, where the fac-isomer absorption is red-shifted by 150 nm, thus reaching the near-IR at approximately 850 nm. Owing to the interesting structural effect on the optical properties, density functional theory (DFT) and time-dependent DFT calculations have been implemented to enlighten the experimental data and prove that exciton coupling is at the origin of the observed shift. The electronic properties have been investigated and, as corroborated by electrochemical data, the presence of the hpp ligand strongly affects the oxidation potential of the ruthenium metal ion, which allows facile fine-tuning of the electronic properties. The luminescence properties of all the compounds have also been investigated (λmax emission = 781-817 nm) and the complexes have longer excited-state lifetimes at room temperature than the parent bis(2,2':6',2''-terpyridine)ruthenium(ii) by 10 to 30 times. PMID:27436338

  5. Angular-momentum-bearing modes in fission

    International Nuclear Information System (INIS)

    The angular-momentum-bearing degrees of freedom involved in the fission process are identified and their influence on experimental observables is discussed. The excitation of these modes is treated in the ''thermal'' limit, and the resulting distributions of observables are calculated. Experiments demonstrating the role of these modes are presented and discussed. 61 refs., 12 figs

  6. Angular Momentum Transport in Accretion Disks

    DEFF Research Database (Denmark)

    E. Pessah, Martin; Chan, Chi-kwan; Psaltis, Dimitrios;

    2007-01-01

    if the resolution were set equal to the natural dissipation scale in astrophysical disks. We conclude that, in order for MRI-driven turbulent angular momentum transport to be able to account for the large value of the effective alpha viscosity inferred observationally, the disk must be threaded by a significant...

  7. On the quantisation of the angular momentum

    CERN Document Server

    Ho, V B

    1994-01-01

    When a hydrogen-like atom is treated as a two dimensional system whose configuration space is multiply connected, then in order to obtain the same energy spectrum as in the Bohr model the angular momentum must be half-integral.

  8. Probabilistic calculation for angular dependence collision

    International Nuclear Information System (INIS)

    This collision probabilistic method is broadly used in cylindrical geometry (in one- or two-dimensions). It constitutes a powerful tool for the heterogeneous Response Method where, the coupling current is of the cosine type, that is, without angular dependence at azimuthal angle θ and proportional to μ (cosine of the θ polar angle). (Author)

  9. Angular and linear momentum of excited ferromagnets

    NARCIS (Netherlands)

    Yan, P.; Kamra, A.; Cao, Y.; Bauer, G.E.W.

    2013-01-01

    The angular momentum vector of a Heisenberg ferromagnet with isotropic exchange interaction is conserved, while under uniaxial crystalline anisotropy the projection of the total spin along the easy axis is a constant of motion. Using Noether's theorem, we prove that these conservation laws persist i

  10. Critical gravitational collapse with angular momentum

    CERN Document Server

    Gundlach, Carsten

    2016-01-01

    We derive a theoretical model of mass and angular momentum scaling in type-II critical collapse with rotation. We focus on the case where the critical solution has precisely one, spherically symmetric, unstable mode. We demonstrate excellent agreement with numerical results for critical collapse of a rotating radiation fluid, which falls into this case.

  11. Optical angular momentum conversion in a nanoslit

    NARCIS (Netherlands)

    Chimento, P.F.; Alkemade, P.F.A.; T Hooft, G.W.; Eliel, E.R.

    2012-01-01

    We demonstrate partial conversion of circularly polarized light into orbital angular momentum-carrying vortex light with opposite-handed circular polarization. This conversion is accomplished in a novel manner using the birefringent properties of a circular subwavelength slit in a thin metal film. O

  12. Wigner Functions and Quark Orbital Angular Momentum

    Directory of Open Access Journals (Sweden)

    Mukherjee Asmita

    2015-01-01

    Full Text Available Wigner distributions contain combined position and momentum space information of the quark distributions and are related to both generalized parton distributions (GPDs and transverse momentum dependent parton distributions (TMDs. We report on a recent model calculation of the Wigner distributions for the quark and their relation to the orbital angular momentum.

  13. A new method for angular displacement measurement

    Institute of Scientific and Technical Information of China (English)

    Caini Zhang(张彩妮); Xiangzhao Wang(王向朝)

    2003-01-01

    We describe a new method for angular displacement measurements that is based on a Fabry-Perot inter-ferometer. A measurement accuracy of 10-s rad is obtained by use of the sinusoidal phase modulatinginterferometry. Another Fabry-Perot interferometer is used to obtain the key initial angle of incidence.

  14. Quantum Entanglement of High Angular Momenta

    International Nuclear Information System (INIS)

    Full text: Orbital angular momentum (OAM) of single photons represents a relatively novel optical degree of freedom for the entanglement of photons. One physical realization of OAM carrying light beams are the so called Laguerre-Gaussian modes which have the required helical phase structure. One big advantage over the well-known polarization degree of freedom is the possibility of realizing entanglement between two photons with very high quantum numbers and momenta respectively. However, the creation of photonic OAM entanglement by the widely used spontaneous parametric down conversion (SPDC) process is limited by the strongly reduced efficiency for higher momenta. We have realized a novel method to create entanglement between two photons which is not constrained by the SPDC efficiency or conservation law for the OAM degree of freedom. We created and measured the entanglement of two photons with up to 600ħ difference in their angular momentum by transferring the polarization entanglement to the orbital angular momentum degree of freedom within an interferometric scheme. Additionally, we used hybrid entangled biphoton states between polarization and OAM to show the angular resolution enhancement in possible remote sensing applications. (author)

  15. Wigner Functions and Quark Orbital Angular Momentum

    OpenAIRE

    Mukherjee Asmita; Nair Sreeraj; Ojha Vikash Kumar

    2014-01-01

    Wigner distributions contain combined position and momentum space information of the quark distributions and are related to both generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs). We report on a recent model calculation of the Wigner distributions for the quark and their relation to the orbital angular momentum.

  16. Photon Orbital Angular Momentum in Astrophysics

    OpenAIRE

    Harwit, Martin

    2003-01-01

    Astronomical observations of the orbital angular momentum of photons, a property of electromagnetic radiation that has come to the fore in recent years, have apparently never been attempted. Here, I show that measurements of this property of photons have a number of astrophysical applications.

  17. Poly[[bis(μ-4,4′-bipyridyl-κ2N:N′bis(thiocyanato-κNmanganese(II] diethyl ether disolvate

    Directory of Open Access Journals (Sweden)

    Mario Wriedt

    2010-07-01

    Full Text Available In the title compound, {[Mn(NCS2(C10H8N22]·2C4H10O}n, the MnII ion is coordinated by four N-bonded 4,4′-bipyridine (bipy ligands and two N-bonded thiocyanate anions in a distorted octahedral coordination geometry. The asymmetric unit consists of one MnII ion and two bipy ligands each located on a twofold rotation axis, as well as one thiocyanate anion and one diethyl ether molecule in general positions. In the crystal structure, the metal centers with terminally bonded thicyanate anions are bridged by the bipy ligands into layers parallel to (001. The diethyl ether solvent molecules occupy the voids of the structure.

  18. Poly[[bis­(μ-4,4′-bipyridyl-κ2 N:N′)bis­(thio­cyanato-κN)manganese(II)] diethyl ether disolvate

    OpenAIRE

    Mario Wriedt; Inke Jess; Christian Näther

    2010-01-01

    In the title compound, {[Mn(NCS)2(C10H8N2)2]·2C4H10O}n, the MnII ion is coordinated by four N-bonded 4,4′-bipyridine (bipy) ligands and two N-bonded thiocyanate anions in a distorted octahedral coordination geometry. The asymmetric unit consists of one MnII ion and two bipy ligands each located on a twofold rotation axis, as well as one thiocyanate anion and one diethyl ether molecule in general positions. In the crystal structure, the metal centers with terminally bonded t...

  19. Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: Characterization, spectroscopic and isothermal titration calorimetry measurements of M 2+ binding and sensing (M 2+ = Ca 2+, Mg 2+)

    Science.gov (United States)

    Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M.; Chary, Kandala V. R.; Houjou, Hirohiko

    2009-07-01

    Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH 2) complexed with cis-Ru(bpy) 2Cl 2·2H 2O provides a complex of composition [Ru(bpy) 2L]·2NH 4PF 6 ( 1), which has been characterized spectroscopically. Its binding behaviour towards Mg 2+ and Ca 2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca 2+ in a more selective manner as compared to Mg 2+.

  20. Ultra-sensitive and super-resolving angular rotation measurement based on photon orbital angular momentum using parity measurement.

    Science.gov (United States)

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan

    2016-08-15

    Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss.

  1. Ultra-sensitive and super-resolving angular rotation measurement based on photon orbital angular momentum using parity measurement.

    Science.gov (United States)

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan

    2016-08-15

    Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss. PMID:27519107

  2. Efficient separation of light's orbital angular momentum

    CERN Document Server

    Mirhosseini, Mohammad; Shi, Zhimin; Boyd, Robert W

    2013-01-01

    The orbital angular momentum (OAM) of light is an attractive degree of freedom for fundamentals studies in quantum mechanics. In addition, the discrete unbounded state-space provided by OAM has been used to enhance classical and quantum communications. The ability to unambiguously measure the OAM of single photons is a key part of all such experiments. However, state-of-the-art methods for sorting OAM modes are limited to a separation efficiency of about 80 percent. Here we demonstrate a method which uses a series of complex optical transformations to enable the measurement of light's OAM with a separation efficiency of more than 92 percent. Further, we demonstrate the separation of modes in the angular position basis, which is mutually unbiased with respect to the OAM basis. The high degree of certainty makes our approach particularly attractive for quantum key distribution systems employing spatial encoding.

  3. Mass and Angular Momentum in General Relativity

    CERN Document Server

    Jaramillo, J L

    2010-01-01

    We present an introduction to mass and angular momentum in General Relativity. After briefly reviewing energy-momentum for matter fields, first in the flat Minkowski case (Special Relativity) and then in curved spacetimes with or without symmetries, we focus on the discussion of energy-momentum for the gravitational field. We illustrate the difficulties rooted in the Equivalence Principle for defining a local energy-momentum density for the gravitational field. This leads to the understanding of gravitational energy-momentum and angular momentum as non-local observables that make sense, at best, for extended domains of spacetime. After introducing Komar quantities associated with spacetime symmetries, it is shown how total energy-momentum can be unambiguously defined for isolated systems, providing fundamental tests for the internal consistency of General Relativity as well as setting the conceptual basis for the understanding of energy loss by gravitational radiation. Finally, several attempts to formulate q...

  4. Phenomenological determination of the orbital angular momentum.

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, G. P.; High Energy Physics; Loyola Univ.

    2009-01-01

    Measurements involving the gluon spin, {Delta}G(x, t) and the corresponding asymmetry, A(x,t) = {Delta}G(x,t)/G(x,t) play an important role in quantitative understanding of proton structure. We have modeled the asymmetry perturbatively and calculated model corrections to obtain information about non-perturbative spin-orbit effects. These models are consistent with existing COMPASS and HERMES data on the gluon asymmetry. The J{sub z} = 1/2 sum rule is used to generate values of orbital angular momentum at LO and NLO. For models consistent with data, the orbital angular momentum is small. Our studies specify accuracy that future measurements should achieve to constrain theoretical models for nucleon structure.

  5. The Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Marriage, Tobias; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Eimer, J.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Mehrle, N.; Miller, A. D.; Miller, N.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

    2014-01-01

    Some of the most compelling inflation models predict a background of primordial gravitational waves (PGW) detectable by their imprint of a curl-like "B-mode" pattern in the polarization of the Cosmic Microwave Background (CMB). The Cosmology Large Angular Scale Surveyor (CLASS) is a novel array of telescopes to measure the B-mode signature of the PGW. By targeting the largest angular scales (>2°) with a multifrequency array, novel polarization modulation and detectors optimized for both control of systematics and sensitivity, CLASS sets itself apart in the field of CMB polarization surveys and opens an exciting new discovery space for the PGW and inflation. This poster presents an overview of the CLASS project.

  6. Ligand Identification Scoring Algorithm (LISA)

    Science.gov (United States)

    Zheng, Zheng; Merz, Kenneth M.

    2011-01-01

    A central problem in de novo drug design is determining the binding affinity of a ligand with a receptor. A new scoring algorithm is presented that estimates the binding affinity of a protein-ligand complex given a three-dimensional structure. The method, LISA (Ligand Identification Scoring Algorithm), uses an empirical scoring function to describe the binding free energy. Interaction terms have been designed to account for van der Waals (VDW) contacts, hydrogen bonding, desolvation effects and metal chelation to model the dissociation equilibrium constants using a linear model. Atom types have been introduced to differentiate the parameters for VDW, H-bonding interactions and metal chelation between different atom pairs. A training set of 492 protein-ligand complexes was selected for the fitting process. Different test sets have been examined to evaluate its ability to predict experimentally measured binding affinities. By comparing with other well known scoring functions, the results show that LISA has advantages over many existing scoring functions in simulating protein-ligand binding affinity, especially metalloprotein-ligand binding affinity. Artificial Neural Network (ANN) was also used in order to demonstrate that the energy terms in LISA are well designed and do not require extra cross terms. PMID:21561101

  7. Clustering, Angular Size and Dark Energy

    OpenAIRE

    R.C. Santos; Lima, J. A. S.

    2008-01-01

    The influence of dark matter inhomogeneities on the angular size-redshift test is investigated for a large class of flat cosmological models driven by dark energy plus a cold dark matter component (XCDM model). The results are presented in two steps. First, the mass inhomogeneities are modeled by a generalized Zeldovich-Kantowski-Dyer-Roeder (ZKDR) distance which is characterized by a smoothness parameter $\\alpha(z)$ and a power index $\\gamma$, and, second, we provide a statistical analysis t...

  8. Time-dependent angularly averaged inverse transport

    OpenAIRE

    Bal, Guillaume; Jollivet, Alexandre

    2009-01-01

    This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability results on the reconstruction of the absorption and scattering parameters with respect to the measured al...

  9. Angular Momentum in Loop Quantum Gravity

    OpenAIRE

    Bojowald, Martin

    2000-01-01

    An angular momentum operator in loop quantum gravity is defined using spherically symmetric states as a non-rotating reference system. It can be diagonalized simultaneously with the area operator and has the familiar spectrum. The operator indicates how the quantum geometry of non-rotating isolated horizons can be generalized to rotating ones and how the recent computations of black hole entropy can be extended to rotating black holes.

  10. Angular Momentum Sharing in Dissipative Collisions

    Science.gov (United States)

    Casini, G.; Poggi, G.; Bini, M.; Calamai, S.; Maurenzig, P. R.; Olmi, A.; Pasquali, G.; Stefanini, A. A.; Taccetti, N.; Steckmeyer, J. C.; Laforest, R.; Saint-Laurent, F.

    1999-09-01

    Light charged particles emitted by the projectilelike fragment were measured in the direct and reverse collision of 93Nb and 116Sn at 25A MeV. The experimental multiplicities of hydrogen and helium particles as a function of the primary mass of the emitting fragment show evidence for a correlation with net mass transfer. The ratio of hydrogen and helium multiplicities points to a dependence of the angular momentum sharing on the net mass transfer.

  11. Angular momentum sharing in dissipative collisions

    CERN Document Server

    Casini, G; Bini, M; Calamai, S; Maurenzig, P R; Olmi, A; Pasquali, G; Stefanini, A A; Taccetti, N; Steckmeyer, J C; Laforest, R; Saint-Laurent, F

    1999-01-01

    Light charged particles emitted by the projectile-like fragment were measured in the direct and reverse collision of $^{93}$Nb and $^{116}$Sn at 25 AMeV. The experimental multiplicities of Hydrogen and Helium particles as a function of the primary mass of the emitting fragment show evidence for a correlation with net mass transfer. The ratio of Hydrogen and Helium multiplicities points to a dependence of the angular momentum sharing on the net mass transfer.

  12. Angular resolution of stacked resistive plate chambers

    CERN Document Server

    Samuel, Deepak; Murgod, Lakshmi P

    2016-01-01

    We present here detailed derivations of mathematical expressions for the angular resolution of a set of stacked resistive plate chambers (RPCs). The expressions are validated against experimental results using data collected from the prototype detectors (without magnet) of the upcoming India-based Neutrino Observatory (INO). In principle, these expressions can be used for any other detector with an architecture similar to that of RPCs.

  13. Angular Momentum of Dark Matter Black Holes

    OpenAIRE

    Frampton, Paul H.

    2016-01-01

    The putative black holes which may constitute all the dark matter are described by a Kerr metric with only two parameters, mass M and angular momentum J. There has been little discussion of J since it plays no role in the upcoming attempt at detection by microlensing. Nevertheless J does play a central role in understanding the previous lack of detection, especially of CMB distortion. We explain why bounds previously derived from lack of CMB distortion are too strong for primordial black hole...

  14. Arbitrary orbital angular momentum of photons

    OpenAIRE

    Pan, Yue; Gao, Xu-Zhen; Ren, Zhi-Cheng; Wang, Xi-Lin; Tu, Chenghou; Li, Yongnan; Wang, Hui-Tian

    2015-01-01

    Orbital angular momentum (OAM) of photons, as a new fundamental degree of freedom, has excited a great diversity of interest, because of a variety of emerging applications. Arbitrarily tunable OAM has gained much attention, but its creation remains still a tremendous challenge. We demonstrate the realization of well-controlled arbitrary OAM in both theory and experiment. We present the concept of general OAM, which extends the OAM carried by the scalar vortex field to the OAM carried by the a...

  15. Quark Orbital Angular Momentum in the Baryon

    OpenAIRE

    Song, Xiaotong

    2000-01-01

    Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as a function of the partition factor $\\kappa$ and the chiral splitting probability $a$ is shown...

  16. Wilson lines and orbital angular momentum

    OpenAIRE

    Lorce, Cédric

    2013-01-01

    We present an explicit realization of the Chen et al. approach to the proton spin decomposition in terms of Wilson lines, generalizing the light-front gauge-invariant extensions discussed recently by Hatta. Particular attention is drawn to the residual gauge freedom by further separating the pure-gauge term into contour and residual terms. We show that the kinetic orbital angular momentum operator can be expressed in terms of the Wigner operator only when the momentum variable is integrated o...

  17. Orbital angular momentum photonic quantum interface

    OpenAIRE

    Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen; Guo, Guang-Can

    2014-01-01

    Light carrying orbital angular momentum (OAM) has great potential in enhancing the information channel capacity in both classical and quantum optical communications. Long distance optical communication requires the wavelengths of light are situated in the low-loss communication windows, but most quantum memories currently being developed for use in a quantum repeater work at different wavelengths, so a quantum interface to bridge the wavelength gap is necessary. So far, such an interface for ...

  18. Orbital angular momentum-entanglement frequency transducer

    OpenAIRE

    Zhou, Zhi-Yuan; Liu, Shi-Long; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photons orbital angular momentum OAM degrees of freedom is preferred in harnessing the ...

  19. Wigner distributions and quark orbital angular momentum

    OpenAIRE

    Cedric LorceOrsay, IPN and Orsay, LPT; Barbara Pasquini(Pavia U. and INFN, Pavia)

    2015-01-01

    We discuss the quark phase-space or Wigner distributions of the nucleon which combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. In particular, we present results for the distribution of unpolarized quarks in a longitudinally polarized nucleon obtained in a light-front constituent quark model. We show how the quark orbital angular momentum can be extracted from the Wigner distributions a...

  20. Orbital angular momentum entanglement in turbulence

    OpenAIRE

    Ibrahim, Alpha Hamadou; Roux, Filippus S.; McLaren, Melanie; Konrad, Thomas; Forbes, Andrew

    2013-01-01

    The turbulence induced decay of orbital angular momentum (OAM) entanglement between two photons is investigated numerically and experimentally. To compare our results with previous work, we simulate the turbulent atmosphere with a single phase screen based on the Kolmogorov theory of turbulence. We consider two different scenarios: in the first only one of the two photons propagates through turbulence, and in the second both photons propagate through uncorrelated turbulence. Comparing the ent...

  1. Four-photon orbital angular momentum entanglement

    OpenAIRE

    Hiesmayr, B. C.; De Dood, M.J.A.; Löffler, W.

    2015-01-01

    Quantum entanglement shared between more than two particles is essential to foundational questions in quantum mechanics, and upcoming quantum information technologies. So far, up to 14 two-dimensional qubits have been entangled, and an open question remains if one can also demonstrate entanglement of higher-dimensional discrete properties of more than two particles. A promising route is the use of the photon orbital angular momentum (OAM), which enables implementation of novel quantum informa...

  2. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    OpenAIRE

    Hockett, Paul; Wollenhaupt, Matthias; Baumert, Thomas,

    2015-01-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the cohere...

  3. Angular Diameter Distances in Clumpy Friedmann Universes

    OpenAIRE

    Tomita, Kenji

    1998-01-01

    Solving null-geodesic equations, behavior of angular diameter distances is studied in inhomogeneous cosmological models, which are given by performing N-body simulations with the CDM spectrum. The distances depend on the separation angle of ray pairs, the mass and the radius of particles cosisting of galaxies and dark matter balls, and cosmological model parameters. The calculated distances are compared with the Dyer- Roeder distance, and after many ray-shooting, the average, dispersion and d...

  4. Angular quadratures for improved transport computations

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Shumays, I.K.

    1999-07-22

    This paper introduces new octant-range, composite-type Gauss and mid-point rule angular quadrature formulas for neutron and photon transport computations. A generalization to octant-range quadratures is also introduced in order to allow for discontinuities at material interfaces for two- and three-dimensional transport problems which can be modeled with 60-degree triangular or hexagonal mesh subdivisions in the x-y plane.

  5. Localization of angular momentum in optical waves propagating through turbulence.

    Science.gov (United States)

    Sanchez, Darryl J; Oesch, Denis W

    2011-12-01

    This is the first in a series of papers demonstrating that photons with orbital angular momentum can be created in optical waves propagating through distributed turbulence. The scope of this first paper is much narrower. Here, we demonstrate that atmospheric turbulence can impart non-trivial angular momentum to beams and that this non-trivial angular momentum is highly localized. Furthermore, creation of this angular momentum is a normal part of propagation through atmospheric turbulence.

  6. Angular momentum of a brane-world model

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper we discuss the properties of the general covariant angular momentum of a fivedimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of the inflationary RS model are all zero while the others are non-zero, which agrees with the results from ordinary RS model.

  7. Study of the Angular Distribution of Scintillation Photons

    CERN Document Server

    Fornaro, Giulia Alice; Ghezzi, Alessio; Knapitsch, Arno; Modrzynski, Pawel; Pizzichemi, Marco; Lecoq, Paul; Auffray, Etiennette

    2014-01-01

    This paper presents a characterization method to experimentally determine the angular distribution of scintillation light. By exciting LYSO crystals with a radioactive source, we measured the light angular profiles obtained with samples of different geometries in different conditions of wrapping. We also measured the angular distribution of light emitting in glue and compared it with the one emitting in air. Angular distribution of light output of photonic crystals is also provided. Consistency of the measurements is verified with conventional light output measurements.

  8. Contactless Measurement of Angular Velocity using Circularly Polarized Antennas

    OpenAIRE

    Sipal, Vit; Narbudowicz, Adam; Ammann, Max

    2014-01-01

    An innovative method to measure the angular velocity using circularly polarized antennas is proposed. Due to the properties of circular polarization, the angular velocity is frequency modulated (FM) on a wireless carrier. This enables a low-cost precise continuous measurement of angular velocity using a standard FM demodulator. The hardware can be easily adapted for both high and low angular velocity values. The precise alignment angle between the antennas can be determined if the initial ant...

  9. Quark Orbital-Angular-Momentum Distribution in the Nucleon

    OpenAIRE

    Hoodbhoy, Pervez; Ji, Xiangdong; Lu, Wei

    1998-01-01

    We introduce gauge-invariant quark and gluon angular momentum distributions after making a generalization of the angular momentum density operators. From the quark angular momentum distribution, we define the gauge-invariant and leading-twist quark {\\it orbital} angular momentum distribution $L_q(x)$. The latter can be extracted from data on the polarized and unpolarized quark distributions and the off-forward distribution $E(x)$ in the forward limit. We comment upon the evolution equations o...

  10. Angular Momentum of a Brane-world Model

    CERN Document Server

    Jia, Bei; Zhang, Peng-Ming

    2008-01-01

    In this paper we discuss the properties of the general covariant angular momentum of a five-dimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of are all zero while the others are non-zero, which agrees with the results from ordinary RS model.

  11. A neural circuit for angular velocity computation

    Directory of Open Access Journals (Sweden)

    Samuel B Snider

    2010-12-01

    Full Text Available In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly-tunable wing-steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuro-mechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.

  12. The Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Harrington, Kathleen; Marriange, Tobias; Aamir, Ali; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe; Denis, Kevin; Moseley, Samuel H.; Rostem, Karwan; Wollack, Edward

    2016-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

  13. The Cosmology Large Angular Scale Surveyor

    CERN Document Server

    Harrington, Kathleen; Ali, Aamir; Appel, John W; Bennett, Charles L; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T; Colazo, Felipe; Dahal, Sumit; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Fluxa, Pedro; Halpern, Mark; Hilton, Gene; Hinshaw, Gary F; Hubmayr, Johannes; Iuliano, Jeffery; Karakla, John; McMahon, Jeff; Miller, Nathan T; Moseley, Samuel H; Palma, Gonzalo; Parker, Lucas; Petroff, Matthew; Pradenas, Bastián; Rostem, Karwan; Sagliocca, Marco; Valle, Deniz; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2016-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70\\% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad f...

  14. A neural circuit for angular velocity computation.

    Science.gov (United States)

    Snider, Samuel B; Yuste, Rafael; Packer, Adam M

    2010-01-01

    In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly tunable wing steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuromechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob. PMID:21228902

  15. A critique of the angular momentum sum rules and a new angular momentum sum rule

    CERN Document Server

    Bakker, B L G; Trueman, T L

    2004-01-01

    We show that the expressions in the literature for the tensorial structure of the hadronic matrix elements of the angular momentum operators J are incorrect. Given this disagreement with the published results, we have taken pains to derive the correct expressions in three different ways, two involving explicit physical wave packets and the third, totally independent, based upon the rotational properties of the state vectors. Surprisingly it turns out that the results are very sensitive to the type of relativistic spin state used to describe the motion of the particle i.e. whether a canonical (i.e. boost) state or a helicity state is utilized. We present results for the matrix elements of the angular momentum operators, valid in an arbitrary Lorentz frame, both for helicity states and canonical states. These results are relevant for the construction of angular momentum sum rules, relating the angular momentum of a nucleon to the spin and orbital angular momentum of its constituents. Moreover, we show that it i...

  16. Angular Dispersion and Deflection Function for Heavy Ion Elastic Scattering

    Institute of Scientific and Technical Information of China (English)

    BAI Zhen; MAO Rui-Shi; YUAN Xiao-Hua; Xu Zhi-Guo; ZHANG Hong-Bin; XU Hua-Gen; QI Hui-Rong; WANG Yue; JIA Fei; WU Li-Jie; DING Xian-Li; WANG Qi; GAO Qi; GAO Hui; LI Song-Lin; LI Jun-Qing; ZHANG Ya-Peng; XIAO Guo-Qing; JIN Gen-Ming; REN Zhong-Zhou; ZHOU Shan-Gui; XU Wang; HAN Jian-Long; Fan Gong-Tao; ZHANG Shuang-Quan; PANG Dan-Yang; SERGEY Yu-Kun; XIAO Zhi-Gang; XU Hu-Shan; SUN Zhi-Yu; HU Zheng-Guo; ZHANG Xue-Ying; WANG Hong-Wei

    2007-01-01

    The differential cross sections for elastic scattering products of17 F on 208 Pb have been measured.The angular dispersion plots of In(dσ/dθ)versus θ2 are obtained from the angular distribution of the elastic scattering differential cross sections.Systematical analysis on the angular dispersion for the available experimental data indicates that there is an angular dispersion turning angle at forward angular range within the grazing angle.This turning angle can be clarified as nuclear rainbow in classical deflection function.The exotic behaviour of the nuclear rainbow angle offers a new probe to investigate the halo and skin phenomena.

  17. Analysis of orbital angular momentum of a misaligned optical beam

    Energy Technology Data Exchange (ETDEWEB)

    Vasnetsov, M V [Optics Group, Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Pas' ko, V A [Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine); Soskin, M S [Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine)

    2005-02-01

    We report an analysis of the orbital angular momentum of an optical beam misaligned with respect to a reference axis. Both laterally displaced and angularly deflected Laguerre-Gaussian beams are represented in terms of the superposition of azimuthal harmonics with well-defined orbital angular momentum. Simultaneous parallel displacement and angular tilt cause the coupling between azimuthal harmonics and therefore change the projection of the orbital angular momentum on the reference axis. Rotation of beams around the reference axis was simulated by attributing corresponding rotational frequency shifts to the components.

  18. Synthesis, Structure, and Properties of Al((R)bpy)3 Complexes (R = t-Bu, Me): Homoleptic Main-Group Tris-bipyridyl Compounds.

    Science.gov (United States)

    DeCarlo, Samantha; Mayo, Dennis H; Tomlinson, Warren; Hu, Junkai; Hooper, Joseph; Zavalij, Peter; Bowen, Kit; Schnöckel, Hansgeorg; Eichhorn, Bryan

    2016-05-01

    The neutral homoleptic tris-bpy aluminum complexes Al((R)bpy)3, where R = tBu (1) or Me (2), have been synthesized from reactions between AlX precursors (X = Cl, Br) and neutral (R)bpy ligands through an aluminum disproportion process. The crystalline compounds have been characterized by single-crystal X-ray diffraction, electrochemical experiments, EPR, magnetic susceptibility, and density functional theory (DFT) studies. The collective data show that 1 and 2 contain Al(3+) metal centers coordinated by three bipyridine (bpy(•))(1-) monoanion radicals. Electrochemical studies show that six redox states are accessible from the neutral complexes, three oxidative and three reductive, that involve oxidation or reduction of the coordinated bpy ligands to give neutral (R)bpy or (R)bpy(2-) dianions, respectively. Magnetic susceptibility measurements (4-300 K) coupled with DFT studies show strong antiferromagnetic coupling of the three unpaired electrons located on the (R)bpy ligands to give S = (1)/2 ground states with low lying S = (3)/2 excited states that are populated above 110 K (1) and 80 K (2) in the solid-state. Complex 2 shows weak 3D magnetic interactions at 19 K, which is not observed in 1 or the related [Al(bpy)3] complex. PMID:27064350

  19. Whole-body angular momentum during stair ascent and descent.

    Science.gov (United States)

    Silverman, Anne K; Neptune, Richard R; Sinitski, Emily H; Wilken, Jason M

    2014-04-01

    The generation of whole-body angular momentum is essential in many locomotor tasks and must be regulated in order to maintain dynamic balance. However, angular momentum has not been investigated during stair walking, which is an activity that presents a biomechanical challenge for balance-impaired populations. We investigated three-dimensional whole-body angular momentum during stair ascent and descent and compared it to level walking. Three-dimensional body-segment kinematic and ground reaction force (GRF) data were collected from 30 healthy subjects. Angular momentum was calculated using a 13-segment whole-body model. GRFs, external moment arms and net joint moments were used to interpret the angular momentum results. The range of frontal plane angular momentum was greater for stair ascent relative to level walking. In the transverse and sagittal planes, the range of angular momentum was smaller in stair ascent and descent relative to level walking. Significant differences were also found in the ground reaction forces, external moment arms and net joint moments. The sagittal plane angular momentum results suggest that individuals alter angular momentum to effectively counteract potential trips during stair ascent, and reduce the range of angular momentum to avoid falling forward during stair descent. Further, significant differences in joint moments suggest potential neuromuscular mechanisms that account for the differences in angular momentum between walking conditions. These results provide a baseline for comparison to impaired populations that have difficulty maintaining dynamic balance, particularly during stair ascent and descent.

  20. ANGULAR MOMENTUM AND GALAXY FORMATION REVISITED

    Energy Technology Data Exchange (ETDEWEB)

    Romanowsky, Aaron J. [University of California Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Fall, S. Michael [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2012-12-15

    Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j{sub *} and mass M{sub *} (thus extending earlier work by Fall). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as 10 effective radii, and find that data at two effective radii are generally sufficient to estimate total j{sub *} reliably. Our results contravene suggestions that ellipticals could harbor large reservoirs of hidden j{sub *} in their outer regions owing to angular momentum transport in major mergers. We then carry out a comprehensive analysis of extended kinematic data from the literature for a sample of {approx}100 nearby bright galaxies of all types, placing them on a diagram of j{sub *} versus M{sub *}. The ellipticals and spirals form two parallel j{sub *}-M{sub *} tracks, with log-slopes of {approx}0.6, which for the spirals are closely related to the Tully-Fisher relation, but for the ellipticals derives from a remarkable conspiracy between masses, sizes, and rotation velocities. The ellipticals contain less angular momentum on average than spirals of equal mass, with the quantitative disparity depending on the adopted K-band stellar mass-to-light ratios of the galaxies: it is a factor of {approx}3-4 if mass-to-light ratio variations are neglected for simplicity, and {approx}7 if they are included. We decompose the spirals into disks and bulges and find that these subcomponents follow j{sub *}-M{sub *} trends similar to the overall ones for spirals and ellipticals. The lenticulars have an intermediate trend, and we propose that the morphological types of galaxies reflect disk and bulge subcomponents that follow

  1. Why mercury prefers soft ligands

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, Demian M [ORNL; Guo, Hao-Bo [ORNL; Gu, Baohua [ORNL; Parks, Jerry M [ORNL; Summers, Anne [University of Georgia, Athens, GA; Miller, S [University of California, San Francisco; Liang, Liyuan [ORNL; Smith, Jeremy C [ORNL

    2013-01-01

    Mercury (Hg) is a major global pollutant arising from both natural and anthropogenic sources. Defining the factors that determine the relative affinities of different ligands for the mercuric ion, Hg2+, is critical to understanding its speciation, transformation, and bioaccumulation in the environment. Here, we use quantum chemistry to dissect the relative binding free energies for a series of inorganic anion complexes of Hg2+. Comparison of Hg2+ ligand interactions in the gaseous and aqueous phases shows that differences in interactions with a few, local water molecules led to a clear periodic trend within the chalcogenide and halide groups and resulted in the well-known experimentally observed preference of Hg2+ for soft ligands such as thiols. Our approach establishes a basis for understanding Hg speciation in the biosphere.

  2. Angular Momentum Sensitive Two-Center Interference

    Science.gov (United States)

    Ilchen, M.; Glaser, L.; Scholz, F.; Walter, P.; Deinert, S.; Rothkirch, A.; Seltmann, J.; Viefhaus, J.; Decleva, P.; Langer, B.; Knie, A.; Ehresmann, A.; Al-Dossary, O. M.; Braune, M.; Hartmann, G.; Meissner, A.; Tribedi, L. C.; AlKhaldi, M.; Becker, U.

    2014-01-01

    In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

  3. Statistical analysis of angular correlation measurements

    International Nuclear Information System (INIS)

    Obtaining the multipole mixing ratio, δ, of γ transitions in angular correlation measurements is a statistical problem characterized by the small number of angles in which the observation is made and by the limited statistic of counting, α. The inexistence of a sufficient statistics for the estimator of δ, is shown. Three different estimators for δ were constructed and their properties of consistency, bias and efficiency were tested. Tests were also performed in experimental results obtained in γ-γ directional correlation measurements. (Author)

  4. Linear Upconversion of Orbit Angular Momentum

    CERN Document Server

    Ding, Dong-Sheng; Shi, Bao-Sen; Zou, Xu-Bo; Guo, Guang-Can

    2012-01-01

    We experimentally demonstrate that an infrared light imprinted the orbit angular momentum is linearly converted into a visible light using Four-wave mixing (FWM) via a Ladder-type configuration in Rb85 atoms. Simultaneously, we theoretically simulate this linear conversion process, and theoretical analysis is in reasonable agreement with the experimental result. A large single-photon detuning is used to reduce the absorption of the atoms to the up-converted light and to avoid the pattern formation in FWM process. The multi-mode image linear conversion is important for applications in image communications, astrophysics and quantum information so on.

  5. Time-dependent angularly averaged inverse transport

    International Nuclear Information System (INIS)

    This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. Such measurement settings find applications in medical and geophysical imaging. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability results on the reconstruction of the absorption and scattering parameters with respect to the measured albedo operator. The stability results are obtained by a precise decomposition of the measurements into components with different singular behavior in the time domain

  6. Time-dependent angularly averaged inverse transport

    CERN Document Server

    Bal, Guillaume

    2009-01-01

    This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability results on the reconstruction of the absorption and scattering parameters with respect to the measured albedo operator. The stability results are obtained by a precise decomposition of the measurements into components with different singular behavior in the time domain.

  7. Angular Momentum of Dark Matter Black Holes

    CERN Document Server

    Frampton, Paul H

    2016-01-01

    The putative black holes which may constitute all the dark matter are described by a Kerr metric with only two parameters, mass M and angular momentum J. There has been little discussion of J since it plays no role in the upcoming attempt at detection by microlensing. Nevertheless J does play a central role in understanding the previous lack of detection, especially of CMB distortion. We explain why bounds previously derived from lack of CMB distortion are too strong for primordial black holes with J non-vanishing. Almost none of the dark matter black holes can be from stellar collapse, and nearly all are primordial, to avoid excessive CMB distortion.

  8. Angular momentum evolution of galaxies in EAGLE

    CERN Document Server

    Lagos, Claudia del P; Stevens, Adam R H; Cortese, Luca; Padilla, Nelson D; Davis, Timothy A; Contreras, Sergio; Croton, Darren

    2016-01-01

    We use EAGLE to study the specific angular momentum of galaxies, j, at z1.2, and then increase as lstars~a. Galaxy mergers reduce lstars by a factor of 2-3. These tracks are driven by both the evolution of the total jstars but also its radial distribution. Regardless of the aperture used to measure j, two distinct channels leading to low jstars in galaxies at z=0 are identified: (i) galaxy mergers, and (ii) early formation of most of the stars.

  9. Angular correlation studies in noble gases

    Science.gov (United States)

    Coleman, P. G.

    1990-01-01

    There has been a recent revival of interest in the measurement of angular correlation of annihilation photons from the decay of positrons and positronium in gases. This revival has been stimulated by the possibility offered by the technique to shed new light on the apparently low positronium formation fraction in the heavier noble gases and to provide information on positronium quenching processes in gases such as oxygen. There is also the potential for learning about positronium slowing down in gases. This review focuses on experimental noble gas work and considers what new information has been, and may be, gained from these studies.

  10. Angular Distributions of Discrete Mesoscale Mapping Functions

    Directory of Open Access Journals (Sweden)

    Kroszczyński Krzysztof

    2015-08-01

    Full Text Available The paper presents the results of analyses of numerical experiments concerning GPS signal propagation delays in the atmosphere and the discrete mapping functions defined on their basis. The delays were determined using data from the mesoscale non-hydrostatic weather model operated in the Centre of Applied Geomatics, Military University of Technology. A special attention was paid to investigating angular characteristics of GPS slant delays for low angles of elevation. The investigation proved that the temporal and spatial variability of the slant delays depends to a large extent on current weather conditions

  11. All-fiber sensor of angular velocity

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A.TS.; Vlasenko, O.A.; Dianov, E.M.; Diankov, G.L.; Zafirova, B.S.

    1989-06-01

    The paper reports the construction of an all-fiber optical sensor of angular velocity whose operation is based on the Sagnac effect in a fiber ring interferometer. An all-fiber system does not require the use of external discrete optical elements; division, polarization, and modulation functions are performed by the fiber waveguide itself. The fiber elements and sensor are constructed on the basis of slightly anisotropic fiber waveguides. The sensitivity of the device was 0.0077 deg/sq rt hr, while the zero drift was 0.5 deg/hr. 6 refs.

  12. The Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Eimer, Joseph; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Marriage, T.; Mehrle, N.; Miller, A. D.; Miller, N.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an array of telescopes designed to search for the signature of inflation in the polarization of the Cosmic Microwave Background (CMB). By combining the strategy of targeting large scales (>2 deg) with novel front-end polarization modulation and novel detectors at multiple frequencies, CLASS will pioneer a new frontier in ground-based CMB polarization surveys. In this talk, I give an overview of the CLASS instrument, survey, and outlook on setting important new limits on the energy scale of inflation.

  13. Angular Momentum Transfer in Catastrophic Asteroid Impacts

    Science.gov (United States)

    Love, S. G.; Ahrens, T. J.

    1996-09-01

    Incomplete knowledge of angular momentum transfer in asteroid impacts has hampered efforts to deduce asteroid collisional histories from their rotation rates. This problem traditionally has been investigated using impact experiments on cm-scale, strength-dominated targets. Recent evidence, however, indicates that impacts on asteroids of km size and larger may be controlled by gravity rather than strength, and that the analogy to laboratory impacts may not hold. Accordingly, we have modelled catastrophic impacts on gravitating asteroids to better understand angular momentum transfer in such events. We employ a 3--D, strengthless, gravitating SPH computer code. Target bodies are 10 to 1000 km in diameter and do not initially rotate. Impact speeds are 3--7 km/s; impact angles are 15--75(deg) . Each target is composed of 1791 mass elements: spatial resolution is coarse but acceptable for large scale energy transfer. We simulate the hydrodynamic phase of each impact, after which particle motions are ballistic and treated analytically. Escaping particles have kinetic energy greater than the gravitational energy binding them to the rest of the system; the others reaccrete to form a ``rubble pile'' which is assumed spherical. The rubble pile's size, mass, and angular momentum define its rotation rate. Spin rates for ejected fragments cannot be determined. The target's final spin period depends on the impact angle and the fraction of target mass ejected, but not on impact speed or target size in the ranges tested. The lack of size dependence cannot explain the observed excess of slowly rotating asteroids of ~ 100 km diameter. The fraction of projectile angular momentum retained by the target varies dramatically with impact speed and angle and with target size and fraction of mass removed, complicating its use in models where collision geometry varies. The final spin period of an asteroid losing 50% of its mass is 6--10 hours, comparable to the asteroidal mean of 8 hours

  14. Angular Diameter Distances in Clumpy Friedmann Universes

    CERN Document Server

    Tomita, K

    1998-01-01

    Solving null-geodesic equations, behavior of angular diameter distances is studied in inhomogeneous cosmological models, which are given by performing N-body simulations with the CDM spectrum. The distances depend on the separation angle of ray pairs, the mass and the radius of particles cosisting of galaxies and dark matter balls, and cosmological model parameters. The calculated distances are compared with the Dyer- Roeder distance, and after many ray-shooting, the average, dispersion and distribution of the clumpiness parameter are derived.

  15. Angular anisotropy representation by probability tables

    International Nuclear Information System (INIS)

    In this paper, we improve point-wise or group-wise angular anisotropy representation by using probability tables. The starting point of this study was to give more flexibility (sensitivity analysis) and more accuracy (ray effect) to group-wise anisotropy representation by Dirac functions, independently introduced at CEA (Mao, 1998) and at IRSN (Le Cocq, 1998) ten years ago. Basing ourselves on our experience of cross-section description, acquired in CALENDF (Sublet et al., 2006), we introduce two kinds of moment based probability tables, Dirac (DPT) and Step-wise (SPT) Probability Tables where the angular probability distribution is respectively represented by Dirac functions or by a step-wise function. First, we show how we can improve equi-probable cosine representation of point-wise anisotropy by using step-wise probability tables. Then we show, by Monte Carlo techniques, how we can obtain a more accurate description of group-wise anisotropy than the one usually given by a finite expansion on a Legendre polynomial basis (that can induce negative values) and finally, we describe it by Dirac probability tables. This study is carried out in the framework of GALILEE project R and D activities (Coste-Delclaux, 2008). (authors)

  16. Detection and recognition of angular frequency patterns.

    Science.gov (United States)

    Wilson, Hugh R; Propp, Roni

    2015-05-01

    Previous research has extensively explored visual encoding of smoothly curved, closed contours described by sinusoidal variation of pattern radius as a function of polar angle (RF patterns). Although the contours of many biologically significant objects are curved, we also confront shapes with a more jagged and angular appearance. To study these, we introduce here a novel class of visual stimuli that deform smoothly from a circle to an equilateral polygon with N sides (AF patterns). Threshold measurements reveal that both AF and RF patterns can be discriminated from circles at the same deformation amplitude, approximately 18.0arcsec, which is in the hyperacuity range. Thresholds were slightly higher for patterns with 3.0 cycles than for those with 5.0 cycles. Discrimination between AF and RF patterns was 75% correct at an amplitude that was approximately 3.0 times the threshold amplitude, which implies that AF and RF patterns activate different neural populations. Experiments with jittered patterns in which the contour was broken into several pieces and shifted inward or outward had much less effect on AF patterns than on RF patterns. Similarly, thresholds for single angles of AF patterns showed no significant difference from thresholds for the entire AF pattern. Taken together, these results imply that the visual system incorporates angles explicitly in the representation of closed object contours, but it suggests that angular contours are represented more locally than are curved contours.

  17. Understanding GRETINA using angular correlation method

    Science.gov (United States)

    Austin, Madeline

    2015-10-01

    The ability to trace the path of gamma rays through germanium is not only necessary for taking full advantage of GRETINA but also a promising possibility for homeland security defense against nuclear threats. This research tested the current tracking algorithm using the angular correlation method by comparing results from raw and tracked data to the theoretical model for Co-60. It was found that the current tracking method is unsuccessful in reproducing angular correlation. Variations to the tracking algorithm were made in the FM value, tracking angle, number of angles of separation observed, and window of coincidence in attempt to improve correlation results. From these variations it was observed that having a larger FM improved results, reducing the number of observational angles worsened correlation, and that overall larger tracking angles improved with larger windows of coincidence and vice-verse. Future research would be to refine the angle of measurement for raw data and to explore the possibility of an energy dependence by testing other elements. This work is supported by the United States Department of Energy, Office of Science, under Contract Number DE-AC02-06CH11357

  18. High-angular Resolution Laser Threat Warner

    Directory of Open Access Journals (Sweden)

    Sushil Kumar

    2007-07-01

    Full Text Available In this paper, the design and development aspects of a high-angular resolution laser-threat Warner developed at the Laser Science & Technology Centre (LASTEC, Delhi are presented. It describes a high-angular resolution laser-threat warner capable of giving warning with a resolution of i 3" when it is exposed to laser radiation from visible and near-IR pulsed solid-state laser source. It has a field of view of 90' in the azimuth direction, whereas the elevation coverage is between -5" and + 25". It is capable of handling multiple types of laser threats covering wavelength from 400 nm to 1100 nm and has an operational range of 4 km for a Q-switched laser source energy (10 ns of 10 mJ/pulse and output beam divergence of 1 mrad. The paper also describes its simulated evaluation process and field-testing which it has undergone. The result of field-testing confirms that it meets all its performance specifications mentioned above.

  19. 1D zigzag chain and 0D monomer Cd(II)/Zn(II) compounds based on flexible phenylenediacetic ligand: Synthesis, crystal structures and fluorescent properties

    Science.gov (United States)

    Yang, Fang; Ren, Yixia; Li, Dongsheng; Fu, Feng; Qi, Guangcai; Wang, Yaoyu

    2008-12-01

    Three novel Cd(II)/Zn(II) compounds, [Cd 2(poda) 2(phen) 3(H 2O)] n· nEtOH·3 nH 2O (1), [Zn(poda) 2(bpy)(H 2O)] n(2) and [Zn(Hpoda) 2(bpy)] (3) (H 2poda = 1,2-phenylenediacetic acid, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridyl), have been synthesized and characterized by IR, TG, fluorescent spectrum and single-crystal X-ray diffraction techniques. In 1, poda 2- anions link the adjacent Cd(II) centers to generate a 1D zigzag chain. Furthermore, an unprecedented four-footed "8-shaped" mixed water-ethanol (H 2O) 6(C 2H 5OH) 2 cluster connects four double chains based on 1D zigzag chain into 3D supramolecular architecture. By bis(chelate-monodentate) fashion of poda 2- ligand, compound 2 exhibits 1D zigzag chains, which forming a dense zipper-like 2D structure via strong π-π stacking interactions. Differed from 1 and 2, compound 3 has a mononuclear motif, and displays a 3D 6-connected α-Po net hydrogen-bonded topology. The structure-related solid-state fluorescence spectra of compounds 1 and 2 have been determined.

  20. A race for RAGE ligands.

    Science.gov (United States)

    Schleicher, Erwin D

    2010-08-01

    In experimental animals a causal involvement of the multiligand receptor for advanced glycation end products (RAGE) in the development of diabetic vascular complications has been demonstrated. However, the nature of RAGE ligands present in patients with diabetic nephropathy has not yet been defined; this leaves open the relevance of the RAGE system to the human disease.

  1. Polypharmacology of dopamine receptor ligands.

    Science.gov (United States)

    Butini, S; Nikolic, K; Kassel, S; Brückmann, H; Filipic, S; Agbaba, D; Gemma, S; Brogi, S; Brindisi, M; Campiani, G; Stark, H

    2016-07-01

    Most neurological diseases have a multifactorial nature and the number of molecular mechanisms discovered as underpinning these diseases is continuously evolving. The old concept of developing selective agents for a single target does not fit with the medical need of most neurological diseases. The development of designed multiple ligands holds great promises and appears as the next step in drug development for the treatment of these multifactorial diseases. Dopamine and its five receptor subtypes are intimately involved in numerous neurological disorders. Dopamine receptor ligands display a high degree of cross interactions with many other targets including G-protein coupled receptors, transporters, enzymes and ion channels. For brain disorders like Parkinsońs disease, schizophrenia and depression the dopaminergic system, being intertwined with many other signaling systems, plays a key role in pathogenesis and therapy. The concept of designed multiple ligands and polypharmacology, which perfectly meets the therapeutic needs for these brain disorders, is herein discussed as a general ligand-based concept while focusing on dopaminergic agents and receptor subtypes in particular. PMID:27234980

  2. The SKA as a Doorway to Angular Momentum

    CERN Document Server

    Obreschkow, D; Popping, A; Power, C; Quinn, P; Staveley-Smith, L

    2015-01-01

    Angular momentum is one of the most fundamental physical quantities governing galactic evolution. Differences in the colours, morphologies, star formation rates and gas fractions amongst galaxies of equal stellar/baryon mass M are potentially widely explained by variations in their specific stellar/baryon angular momentum j. The enormous potential of angular momentum science is only just being realised, thanks to the emergence of the first simulations of galaxies with converged spins, paralleled by a dramatic increase in kinematic observations. Such observations are still challenged by the fact that most of the stellar/baryon angular momentum resides at large radii. In fact, the radius that maximally contributes to the angular momentum of an exponential disk (3Re-4Re) is twice as large as the radius that maximally contributes to the disk mass; thus converged measurements of angular momentum require either extremely deep IFS data or, alternatively, kinematic measurements of neutral atomic hydrogen (HI), which ...

  3. Creating high-harmonic beams with controlled orbital angular momentum.

    Science.gov (United States)

    Gariepy, Genevieve; Leach, Jonathan; Kim, Kyung Taec; Hammond, T J; Frumker, E; Boyd, Robert W; Corkum, P B

    2014-10-10

    A beam with an angular-dependant phase Φ = ℓϕ about the beam axis carries an orbital angular momentum of ℓℏ per photon. Such beams are exploited to provide superresolution in microscopy. Creating extreme ultraviolet or soft-x-ray beams with controllable orbital angular momentum is a critical step towards extending superresolution to much higher spatial resolution. We show that orbital angular momentum is conserved during high-harmonic generation. Experimentally, we use a fundamental beam with |ℓ| = 1 and interferometrically determine that the harmonics each have orbital angular momentum equal to their harmonic number. Theoretically, we show how any small value of orbital angular momentum can be coupled to any harmonic in a controlled manner. Our results open a route to microscopy on the molecular, or even submolecular, scale.

  4. Motion fading is driven by perceived, not actual angular velocity.

    Science.gov (United States)

    Kohler, P J; Caplovitz, G P; Hsieh, P-J; Sun, J; Tse, P U

    2010-06-01

    After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. Here we examine the relationship between such 'motion fading' and perceived angular velocity. Using several different dot patterns that generate emergent virtual contours, we demonstrate that whenever there is a difference in the perceived angular velocity of two patterns of dots that are in fact rotating at the same angular velocity, there is also a difference in the time to undergo motion fading for those two patterns. Conversely, whenever two patterns show no difference in perceived angular velocity, even if in fact rotating at different angular velocities, we find no difference in the time to undergo motion fading. Thus, motion fading is driven by the perceived rather than actual angular velocity of a rotating stimulus. PMID:20371254

  5. Angular momentum in quantum mechanics as a group study topic

    International Nuclear Information System (INIS)

    A largely practical approach to the teaching of angular momentum in quantum mechanics at the undergraduate level is described. In an intensive seven week period towards the end of their final year, undergraduates working in pairs perform experiments in nuclear physics which demonstrate some of the important properties of angular momentum. Three experiments are selected and discussed in this article to illustrate the teaching method. The existence of intrinsic spin and parity is investigated by measuring the polarisation of annihilation radiation; the conservation of angular momentum is demonstrated by a measurement of orbital angular momentum in a nucleon transfer reaction and the coupling of angular momenta is illustrated by the method of angular correlation. (author)

  6. Coherent detection of orbital angular momentum in radio

    OpenAIRE

    Daldorff, L. K. S.; S. M. Mohammadi; Bergman, J. E. S.; Isham, B.; Al-Nuaimi, M. K. T.; Forozesh, K.; Carozzi, T.D.

    2015-01-01

    The angular momentum propagated by a beam of radiation has two contributions: spin angular momentum (SAM) and orbital angular momentum (OAM). SAM corresponds to wave polarisation, while OAM-carrying beams are characterized by a phase which is a function of azimuth. We demonstrate experimentally that radio beams propagating OAM can be generated and coherently detected using ordinary electric dipole antennas. The results presented here could pave the way for novel radio OAM applications in tech...

  7. Angular momentum evolution in laser-plasma accelerators

    OpenAIRE

    Thaury, Cédric; E. Guillaume; Corde, Sébastien; Lehe, R.; Le Bouteiller, M.; Ta Phuoc, K.; X. Davoine; Rax, Jean-Marcel; Rax, J. M.; Rousse, Antoine; Malka, Victor

    2013-01-01

    The transverse properties of an electron beam are characterized by two quantities, the emittance which indicates the electron beam extend in the phase space and the angular momentum which allows for non-planar electron trajectories. Whereas the emittance of electron beams produced in laser- plasma accelerator has been measured in several experiments, their angular momentum has been scarcely studied. It was demonstrated that electrons in laser-plasma accelerator carry some angular momentum, bu...

  8. Angular momentum and conservation laws for dynamical black holes

    OpenAIRE

    Hayward, Sean A.

    2006-01-01

    Black holes can be practically located (e.g. in numerical simulations) by trapping horizons, hypersurfaces foliated by marginal surfaces, and one desires physically sound measures of their mass and angular momentum. A generically unique angular momentum can be obtained from the Komar integral by demanding that it satisfy a simple conservation law. With the irreducible (Hawking) mass as the measure of energy, the conservation laws of energy and angular momentum take a similar form, expressing ...

  9. Angular velocity gradients in the solar convection zone

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, P.A.; Foukal, P.V.

    1979-05-01

    We test the hypothesis that the weak influence of rotation upon solar supergranulation, resulting in fluid particles conserving their angular momentum while moving radially, is responsible for the outward decrease in angular velocity inferred from the difference between photospheric plasma and sunspot rotation rates. This test is performed using numerical integrations of a Boussinesq spherical convection model for a thin shell at small Taylor number (implying weak influence of rotation). We find that the convection does maintain an outward decrease in angular velocity, which approaches the limit implied by angular momentum conservation as the Rayleigh number or driving for convection is increased.By examining the energetics of the motion, we verify that the dominant process maintaining the calculated angular velocity profile against viscous diffusion is the inward transport of angular momentum by the convection. Axisymmetric meridional circulation plays virtually no role in this process. We further find there is no tendency for convection weakly influenced by rotation to form an equatorial acceleration. We argue from these and earlier calculations that the origin of the Sun's latitudinal gradient of angular velocity is deep in the convection zone. At these depths there may be a strong tendency for angular velocity to be constant on cylinders, implying a positive radial gradient of angular velocity. The latitude gradient is transmitted to the photosphere by supergranulation which locally produces the negative radial gradient in the top layers. We suggest from the rotation of various magnetic features that the transition from negative to positive radial angular velocity gradient occurs near the bottom of the supergranule layer. We argue that angular momentum conservation in radially moving fluid particles should produce a similar angular velocity profile in compressible convecting fluid layers.

  10. Orbital angular momentum in /sup 3/He-A-italic

    Energy Technology Data Exchange (ETDEWEB)

    Balatskii-breve, A.V.; Mineev, V.P.

    1985-12-01

    The intrinsic angular momentum in the A-italic phase of superfluid /sup 3/He is found in terms of the response to the angular velocity of rotation. It is shown that in the weak-coupling approximation at an arbitrary temperature and with allowance for the Fermi-liquid renormalization the intrinsic angular momentum is small in accordance with the smallness of the asymmetry in the distribution of particles and holes.

  11. Quantum orbital angular momentum of elliptically-symmetric light

    OpenAIRE

    Plick, William N.; Krenn, Mario; Fickler, Robert; Ramelow, Sven; Zeilinger, Anton

    2012-01-01

    We present a quantum mechanical analysis of the orbital angular momentum of a class of recently discovered elliptically-symmetric stable light fields --- the so-called Ince-Gauss modes. We study, in a fully quantum formalism, how the orbital angular momentum of these beams varies with their ellipticity and discover several compelling features, including: non-monotonic behavior, stable beams with real continuous (non-integer) orbital angular momenta, and orthogonal modes with the same orbital ...

  12. Spin and orbital angular momentum of the tensor gauge field

    OpenAIRE

    Chen, Xiang-Song; Zhu, Ben-Chao; Murchadha, Niall Ó

    2011-01-01

    Following the recent studies of the trickiness in spin and orbital angular momentum of the vector gauge fields, we perform here a parallel analysis for the tensor gauge field, which has certain relation to gravitation. Similarly to the vector case, we find a nice feature that after removing all gauge degrees of freedom the angular momentum of the tensor gauge field vanishes for a stationary system. This angular momentum also shows a one-parameter invariance over the infinitely many ways of co...

  13. Quantitative measurement of orbital angular momentum in electron microscopy

    OpenAIRE

    Clark, L.; Béché, A.; Guzzinati, G.; Verbeeck, J.

    2014-01-01

    Abstract: Electron vortex beams have been predicted to enable atomic scale magnetic information measurement, via transfer of orbital angular momentum. Research so far has focused on developing production techniques and applications of these beams. However, methods to measure the outgoing orbital angular momentum distribution are also a crucial requirement towards this goal. Here, we use a method to obtain the orbital angular momentum decomposition of an electron beam, using a multipinhole int...

  14. Orbital angular momentum exchange in post-collision interaction

    Energy Technology Data Exchange (ETDEWEB)

    Burgt, P.J.M. van der; Eck, J. van; Heideman, H.G.M.

    1985-03-14

    The authors have measured the angular distribution of electrons ejected by the He**(2s/sup 2/)/sup 1/S autoionising state after its electron impact excitation via the He/sup -/(2s2p/sup 2/)/sup 2/D resonance. Taking into account interference with electrons from the direct ionisation of helium, analysis of this angular distribution provides evidence for angular momentum exchange between ejected and scattered electrons during the post-collision interaction.

  15. Parton Orbital Angular Momentum and Final State Interactions

    OpenAIRE

    Burkardt, Matthias

    2012-01-01

    Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar.We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asym...

  16. Quark Orbital Angular Momentum in the MIT Bag Model

    OpenAIRE

    Burkardt, Matthias; Jarrah, Abdullah

    2010-01-01

    Using the MIT bag model, we study the contribution from the gluon vector potential due to the spectators to the orbital angular momentum of a quark in the bag model. For $\\alpha_s = {\\cal O}(1)$, this spectator contribution to the quark orbital angular momentum in the gauge-covariant Ji decomposition is of the same order as the non gauge-covariant quark orbital angular momentum and its magnitude is larger for $d$ than for $u$ quarks and negative for both.

  17. Optical communication beyond orbital angular momentum

    Science.gov (United States)

    Trichili, Abderrahmen; Rosales-Guzmán, Carmelo; Dudley, Angela; Ndagano, Bienvenu; Ben Salem, Amine; Zghal, Mourad; Forbes, Andrew

    2016-01-01

    Mode division multiplexing (MDM) is mooted as a technology to address future bandwidth issues, and has been successfully demonstrated in free space using spatial modes with orbital angular momentum (OAM). To further increase the data transmission rate, more degrees of freedom are required to form a densely packed mode space. Here we move beyond OAM and demonstrate multiplexing and demultiplexing using both the radial and azimuthal degrees of freedom. We achieve this with a holographic approach that allows over 100 modes to be encoded on a single hologram, across a wide wavelength range, in a wavelength independent manner. Our results offer a new tool that will prove useful in realizing higher bit rates for next generation optical networks. PMID:27283799

  18. Optical communication beyond orbital angular momentum

    Science.gov (United States)

    Trichili, Abderrahmen; Rosales-Guzmán, Carmelo; Dudley, Angela; Ndagano, Bienvenu; Ben Salem, Amine; Zghal, Mourad; Forbes, Andrew

    2016-06-01

    Mode division multiplexing (MDM) is mooted as a technology to address future bandwidth issues, and has been successfully demonstrated in free space using spatial modes with orbital angular momentum (OAM). To further increase the data transmission rate, more degrees of freedom are required to form a densely packed mode space. Here we move beyond OAM and demonstrate multiplexing and demultiplexing using both the radial and azimuthal degrees of freedom. We achieve this with a holographic approach that allows over 100 modes to be encoded on a single hologram, across a wide wavelength range, in a wavelength independent manner. Our results offer a new tool that will prove useful in realizing higher bit rates for next generation optical networks.

  19. Effects of Angular Momentum on Halo Profiles

    CERN Document Server

    Lentz, Erik W; Rosenberg, Leslie J

    2016-01-01

    The near universality of DM halo density profiles provided by N-body simulations has proven to be robust against changes in total mass density, power spectrum, and some forms of initial velocity dispersion. In this letter we study the effects of coherently spinning up an isolated DM-only progenitor on halo structure. Halos with spins within several standard deviations of the simulated mean ($\\lambda \\lesssim 0.20$) produce profiles with negligible deviations from the universal form. Only when the spin becomes quite large ($\\lambda \\gtrsim 0.20$) do departures become evident. The angular momentum distribution also exhibits a near universal form, which is also independent of halo spin up to $\\lambda \\lesssim 0.20$. A correlation between these epidemic profiles and the presence of a strong bar in the virialized halo is also observed. These bar structures bear resemblance to the radial orbit instability in the rotationless limit.

  20. Arbitrarily tunable orbital angular momentum of photons.

    Science.gov (United States)

    Pan, Yue; Gao, Xu-Zhen; Ren, Zhi-Cheng; Wang, Xi-Lin; Tu, Chenghou; Li, Yongnan; Wang, Hui-Tian

    2016-01-01

    Orbital angular momentum (OAM) of photons, as a new fundamental degree of freedom, has excited a great diversity of interest, because of a variety of emerging applications. Arbitrarily tunable OAM has gained much attention, but its creation remains still a tremendous challenge. We demonstrate the realization of well-controlled arbitrarily tunable OAM in both theory and experiment. We present the concept of general OAM, which extends the OAM carried by the scalar vortex field to the OAM carried by the azimuthally varying polarized vector field. The arbitrarily tunable OAM we presented has the same characteristics as the well-defined integer OAM: intrinsic OAM, uniform local OAM and intensity ring, and propagation stability. The arbitrarily tunable OAM has unique natures: it is allowed to be flexibly tailored and the radius of the focusing ring can have various choices for a desired OAM, which are of great significance to the benefit of surprising applications of the arbitrary OAM. PMID:27378234

  1. Orbital angular momentum photonic quantum interface

    CERN Document Server

    Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen; Guo, Guang-Can

    2014-01-01

    High dimensional orbital angular momentum (OAM) light states are very important in enhancing the information carrying capacity in optical communications and quantum key distributions. Light at wavelengths of fiber communication windows or free space communication windows are suitable for long distance quantum communication, but most quantum processing tasks are performed in the visible wavelength ranges. The interface to bridge the wavelength gap of single photon with Gaussian shape has been realized, however, to create such interface for OAM-carrying light is a great challenge. We report the demonstration of such an interface to frequency up-conversion of herald single photon OAM state from 1560nm to 525nm with high efficiency by using nonlinear crystal in an external cavity. We show that different single photon OAM light shapes are observed directly by using single photon counting camera and the single photon entangled property is retained in the conversion process.

  2. Orbital angular momentum-entanglement frequency transducer

    CERN Document Server

    Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photons orbital angular momentum OAM degrees of freedom is preferred in harnessing the information carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 nm to 525 nm for OAM qubits, OAMpolarization hybrid entangled states, and OAM entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link betwe...

  3. Orbital angular momentum photonic quantum interface

    Institute of Scientific and Technical Information of China (English)

    Zhi-Yuan Zhou; Yan Li; Dong-Sheng Ding; Wei Zhang; Shuai Shi; Bao-Sen Shi; Guang-Can Guo

    2016-01-01

    Light-carrying orbital angular momentum (OAM) has great potential in enhancing the information channel capacity in both classical and quantum optical communications.Long distance optical communication requires the wavelengths of light are situated in the low-loss communication windows,but most quantum memories currently being developed for use in a quantum repeater work at different wavelengths,so a quantum interface to bridge the wavelength gap is necessary.So far,such an interface for OAM-carried light has not been realized yet.Here,we report the first experimental realization of a quantum interface for a heralded single photon carrying OAM using a nonlinear crystal in an optical cavity.The spatial structures of input and output photons exhibit strong similarity.More importantly,single-photon coherence is preserved during up-conversion as demonstrated.

  4. Colliding particles carrying nonzero orbital angular momentum

    Science.gov (United States)

    Ivanov, Igor P.

    2011-05-01

    Photons carrying nonzero orbital angular momentum (twisted photons) are well-known in optics. Recently, using Compton backscattering to boost optical twisted photons to high energies was suggested. Twisted electrons in the intermediate energy range have also been produced recently. Thus, collisions involving energetic twisted particles seem to be feasible and represent a new tool in high-energy physics. Here we discuss some generic features of scattering processes involving twisted particles in the initial and/or final state. In order to avoid additional complications arising from nontrivial polarization states, we focus here on scalar fields only. We show that processes involving twisted particles allow one to perform a Fourier analysis of the plane-wave cross section with respect to the azimuthal angles of the initial particles. In addition, using twisted states, one can probe the autocorrelation function of the amplitude, which is inaccessible in the plane-wave collisions. Finally, we discuss prospects for experimental study of these effects.

  5. Arbitrarily tunable orbital angular momentum of photons

    Science.gov (United States)

    Pan, Yue; Gao, Xu-Zhen; Ren, Zhi-Cheng; Wang, Xi-Lin; Tu, Chenghou; Li, Yongnan; Wang, Hui-Tian

    2016-01-01

    Orbital angular momentum (OAM) of photons, as a new fundamental degree of freedom, has excited a great diversity of interest, because of a variety of emerging applications. Arbitrarily tunable OAM has gained much attention, but its creation remains still a tremendous challenge. We demonstrate the realization of well-controlled arbitrarily tunable OAM in both theory and experiment. We present the concept of general OAM, which extends the OAM carried by the scalar vortex field to the OAM carried by the azimuthally varying polarized vector field. The arbitrarily tunable OAM we presented has the same characteristics as the well-defined integer OAM: intrinsic OAM, uniform local OAM and intensity ring, and propagation stability. The arbitrarily tunable OAM has unique natures: it is allowed to be flexibly tailored and the radius of the focusing ring can have various choices for a desired OAM, which are of great significance to the benefit of surprising applications of the arbitrary OAM. PMID:27378234

  6. Angular characteristics of pion-nucleus interaction

    International Nuclear Information System (INIS)

    In the present paper pion-nucleus interactions have been studied using nuclear emulsion technique. The investigation of these interactions is expected to provide some very useful information about the multiparticle production mechanism. Nuclear emulsion is a material which memorizes the tracks of charged particles. When a primary particle collides with a nucleus, it may interact with the nucleons of the target nucleus in two ways. In the first case, independent reactions may take place between the incident particle and the nucleons present in the target nucleus. Secondly the primary particle may interact coherently with the various nucleons of the target nucleus and the secondary particles are produced. Angular distribution of charged secondaries produced in these interactions has been studied for central collision events. Different workers have used different criterion for the selection of central collisions. We analysed the events with high shower particle multiplicity i.e., Ns ≥ 28 and call them as central collision events

  7. Coherent control of photoelectron wavepacket angular interferograms

    Science.gov (United States)

    Hockett, P.; Wollenhaupt, M.; Baumert, T.

    2015-11-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  8. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    CERN Document Server

    Hockett, Paul; Baumert, Thomas

    2015-01-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  9. Arbitrary orbital angular momentum of photons

    CERN Document Server

    Pan, Yue; Ren, Zhi-Cheng; Wang, Xi-Lin; Tu, Chenghou; Li, Yongnan; Wang, Hui-Tian

    2015-01-01

    Orbital angular momentum (OAM) of photons, as a new fundamental degree of freedom, has excited a great diversity of interest, because of a variety of emerging applications. Arbitrarily tunable OAM has gained much attention, but its creation remains still a tremendous challenge. We demonstrate the realization of well-controlled arbitrary OAM in both theory and experiment. We present the concept of general OAM, which extends the OAM carried by the scalar vortex field to the OAM carried by the azimuthally varying polarized vector field. The arbitrary OAM has the same characteristics as the well-defined integer OAM: intrinsic OAM, uniform local OAM and intensity ring, and propagation stability. The arbitrary OAM has unique natures: it is allowed to be flexibly tailored and the radius of the focusing ring can have various choices for a desired OAM, which are of great significance to the benefit of surprising applications of the arbitrary OAM.

  10. Angular Spectrum Simulation of Pulsed Ultrasound Fields

    DEFF Research Database (Denmark)

    Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

    2009-01-01

    The optimization of non-linear ultrasound imaging should in a first step be based on simulation, as this makes parameter studies considerably easier than making transducer prototypes. Such a simulation program should be capable of simulating non-linear pulsed fields for arbitrary transducer...... geometries for any kind of focusing and apodization. The Angular Spectrum Approach (ASA) is capable of simulating monochromatic non-linear acoustic wave propagation. However, for ultrasound imaging the time response of each specific point in space is required, and a pulsed ASA simulation with multi temporal....... The RMS error of the pulses for all points in the simulated plane is 10.9%. The good agreement between ASA and Field II simulation for the pulsed ultrasound fields obtained in this paper makes it possible to expand Field II to non-linear pulsed fields....

  11. Angular Approach Scanning Ion Conductance Microscopy.

    Science.gov (United States)

    Shevchuk, Andrew; Tokar, Sergiy; Gopal, Sahana; Sanchez-Alonso, Jose L; Tarasov, Andrei I; Vélez-Ortega, A Catalina; Chiappini, Ciro; Rorsman, Patrik; Stevens, Molly M; Gorelik, Julia; Frolenkov, Gregory I; Klenerman, David; Korchev, Yuri E

    2016-05-24

    Scanning ion conductance microscopy (SICM) is a super-resolution live imaging technique that uses a glass nanopipette as an imaging probe to produce three-dimensional (3D) images of cell surface. SICM can be used to analyze cell morphology at nanoscale, follow membrane dynamics, precisely position an imaging nanopipette close to a structure of interest, and use it to obtain ion channel recordings or locally apply stimuli or drugs. Practical implementations of these SICM advantages, however, are often complicated due to the limitations of currently available SICM systems that inherited their design from other scanning probe microscopes in which the scan assembly is placed right above the specimen. Such arrangement makes the setting of optimal illumination necessary for phase contrast or the use of high magnification upright optics difficult. Here, we describe the designs that allow mounting SICM scan head on a standard patch-clamp micromanipulator and imaging the sample at an adjustable approach angle. This angle could be as shallow as the approach angle of a patch-clamp pipette between a water immersion objective and the specimen. Using this angular approach SICM, we obtained topographical images of cells grown on nontransparent nanoneedle arrays, of islets of Langerhans, and of hippocampal neurons under upright optical microscope. We also imaged previously inaccessible areas of cells such as the side surfaces of the hair cell stereocilia and the intercalated disks of isolated cardiac myocytes, and performed targeted patch-clamp recordings from the latter. Thus, our new, to our knowledge, angular approach SICM allows imaging of living cells on nontransparent substrates and a seamless integration with most patch-clamp setups on either inverted or upright microscopes, which would facilitate research in cell biophysics and physiology. PMID:27224490

  12. Whole-body angular momentum in incline and decline walking.

    Science.gov (United States)

    Silverman, Anne K; Wilken, Jason M; Sinitski, Emily H; Neptune, Richard R

    2012-04-01

    Angular momentum is highly regulated over the gait cycle and is important for maintaining dynamic stability and control of movement. However, little is known regarding how angular momentum is regulated on irregular surfaces, such as slopes, when the risk of falling is higher. This study examined the three-dimensional whole-body angular momentum patterns of 30 healthy subjects walking over a range of incline and decline angles. The range of angular momentum was either similar or reduced on decline surfaces and increased on incline surfaces relative to level ground, with the greatest differences occurring in the frontal and sagittal planes. These results suggest that angular momentum is more tightly controlled during decline walking when the risk of falling is greater. In the frontal plane, the range of angular momentum was strongly correlated with the peak hip and knee abduction moments in early stance. In the transverse plane, the strongest correlation occurred with the knee external rotation peak in late stance. In the sagittal plane, all external moment peaks were correlated with the range of angular momentum. The peak ankle plantarflexion, knee flexion and hip extension moments were also strongly correlated with the sagittal-plane angular momentum. These results highlight how able-bodied subjects control angular momentum differently on sloped surfaces relative to level walking and provide a baseline for comparison with pathological populations that are more susceptible to falling. PMID:22325978

  13. Ideal linear-chain polymers with fixed angular momentum.

    Science.gov (United States)

    Brunner, Matthew; Deutsch, J M

    2011-07-01

    The statistical mechanics of a linear noninteracting polymer chain with a large number of monomers is considered with fixed angular momentum. The radius of gyration for a linear polymer is derived exactly by functional integration. This result is then compared to simulations done with a large number of noninteracting rigid links at fixed angular momentum. The simulation agrees with the theory up to finite-size corrections. The simulations are also used to investigate the anisotropic nature of a spinning polymer. We find universal scaling of the polymer size along the direction of the angular momentum, as a function of rescaled angular momentum.

  14. Whole-body angular momentum in incline and decline walking.

    Science.gov (United States)

    Silverman, Anne K; Wilken, Jason M; Sinitski, Emily H; Neptune, Richard R

    2012-04-01

    Angular momentum is highly regulated over the gait cycle and is important for maintaining dynamic stability and control of movement. However, little is known regarding how angular momentum is regulated on irregular surfaces, such as slopes, when the risk of falling is higher. This study examined the three-dimensional whole-body angular momentum patterns of 30 healthy subjects walking over a range of incline and decline angles. The range of angular momentum was either similar or reduced on decline surfaces and increased on incline surfaces relative to level ground, with the greatest differences occurring in the frontal and sagittal planes. These results suggest that angular momentum is more tightly controlled during decline walking when the risk of falling is greater. In the frontal plane, the range of angular momentum was strongly correlated with the peak hip and knee abduction moments in early stance. In the transverse plane, the strongest correlation occurred with the knee external rotation peak in late stance. In the sagittal plane, all external moment peaks were correlated with the range of angular momentum. The peak ankle plantarflexion, knee flexion and hip extension moments were also strongly correlated with the sagittal-plane angular momentum. These results highlight how able-bodied subjects control angular momentum differently on sloped surfaces relative to level walking and provide a baseline for comparison with pathological populations that are more susceptible to falling.

  15. On angular momentum transport in convection-dominated accretion flows

    CERN Document Server

    Igumenshchev, I V

    2002-01-01

    Convection-dominated accretion flow (CDAF) is a promising model to explain underluminous accreting black holes in X-ray binaries and galactic nuclei. I discuss effects of angular momentum transport in viscous hydrodynamical and MHD CDAFs. In hydrodynamical CDAFs, convection transports angular momentum inward, and this together with outward convection transport of thermal energy determine the radial structure of the flow. In MHD CDAFs, convection can transport angular momentum either inward or outward, depending on properties of turbulence in rotating magnetized plasma, which are not fully understood yet. Direction of convection angular momentum transport can affect the law of rotation of MHD CDAFs.

  16. Orbital Angular Momentum in the Chiral Quark Model

    OpenAIRE

    Song, Xiaotong

    1998-01-01

    We developed a new and unified scheme for describing both quark spin and orbital angular momenta in symmetry-breaking chiral quark model. The loss of quark spin in the chiral splitting processes is compensated by the gain of the orbital angular momentum carried by quarks and antiquarks. The sum of both spin and orbital angular momenta carried by quarks and antiquarks is 1/2. The analytic and numerical results for the spin and orbital angular momenta carried by quarks and antiquarks in the nuc...

  17. Quark orbital-angular-momentum distribution in the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Hoodbhoy, P.; Ji, X.; Lu, W. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

    1999-01-01

    We introduce gauge-invariant quark and gluon angular momentum distributions after making a generalization of the angular momentum density operators. From the quark angular momentum distribution, we define the gauge-invariant and leading-twist quark {ital orbital} angular momentum distribution L{sub q}(x). The latter can be extracted from data on the polarized and unpolarized quark distributions and the off-forward distribution E(x) in the forward limit. We comment upon the evolution equations obeyed by this as well as other orbital distributions considered in the literature. {copyright} {ital 1998} {ital The American Physical Society}

  18. Angular dynamics of small crystals in viscous flow

    CERN Document Server

    Fries, J; Mehlig, B

    2016-01-01

    The angular dynamics of a very small ellipsoidal particle in a viscous flow decouples from its translational dynamics, and the particle angular velocity is given by Jeffery's theory. It is known that cuboid particles share these properties. In the literature a special case is most frequently discussed, that of axisymmetric particles, with a continuous rotational symmetry. Here we compute the angular dynamics of crystals that possess a discrete rotational symmetry and certain mirror symmetries, but that do not have a continuous rotational symmetry. We give examples of such particles that nevertheless obey Jeffery's theory. But there are other examples where the angular dynamics is determined by a more general equation of motion.

  19. An NMR strategy for fragment-based ligand screening utilizing a paramagnetic lanthanide probe

    International Nuclear Information System (INIS)

    A nuclear magnetic resonance-based ligand screening strategy utilizing a paramagnetic lanthanide probe is presented. By fixing a paramagnetic lanthanide ion to a target protein, a pseudo-contact shift (PCS) and a paramagnetic relaxation enhancement (PRE) can be observed for both the target protein and its bound ligand. Based on PRE and PCS information, the bound ligand is then screened from the compound library and the structure of the ligand–protein complex is determined. PRE is an isotropic paramagnetic effect observed within 30 Å from the lanthanide ion, and is utilized for the ligand screening in the present study. PCS is an anisotropic paramagnetic effect providing long-range (∼40 Å) distance and angular information on the observed nuclei relative to the paramagnetic lanthanide ion, and utilized for the structure determination of the ligand–protein complex. Since a two-point anchored lanthanide-binding peptide tag is utilized for fixing the lanthanide ion to the target protein, this screening method can be generally applied to non-metal-binding proteins. The usefulness of this strategy was demonstrated in the case of the growth factor receptor-bound protein 2 (Grb2) Src homology 2 (SH2) domain and its low- and high-affinity ligands.

  20. Ligand chain length conveys thermochromism.

    Science.gov (United States)

    Ganguly, Mainak; Panigrahi, Sudipa; Chandrakumar, K R S; Sasmal, Anup Kumar; Pal, Anjali; Pal, Tarasankar

    2014-08-14

    Thermochromic properties of a series of non-ionic copper compounds have been reported. Herein, we demonstrate that Cu(II) ion with straight-chain primary amine (A) and alpha-linolenic (fatty acid, AL) co-jointly exhibit thermochromic properties. In the current case, we determined that thermochromism becomes ligand chain length-dependent and at least one of the ligands (A or AL) must be long chain. Thermochromism is attributed to a balanced competition between the fatty acids and amines for the copper(II) centre. The structure-property relationship of the non-ionic copper compounds Cu(AL)2(A)2 has been substantiated by various physical measurements along with detailed theoretical studies based on time-dependent density functional theory. It is presumed from our results that the compound would be a useful material for temperature-sensor applications. PMID:24943491

  1. Controlled-deactivation cannabinergic ligands.

    Science.gov (United States)

    Sharma, Rishi; Nikas, Spyros P; Paronis, Carol A; Wood, Jodianne T; Halikhedkar, Aneetha; Guo, Jason Jianxin; Thakur, Ganesh A; Kulkarni, Shashank; Benchama, Othman; Raghav, Jimit Girish; Gifford, Roger S; Järbe, Torbjörn U C; Bergman, Jack; Makriyannis, Alexandros

    2013-12-27

    We report an approach for obtaining novel cannabinoid analogues with controllable deactivation and improved druggability. Our design involves the incorporation of a metabolically labile ester group at the 2'-position on a series of (-)-Δ(8)-THC analogues. We have sought to introduce benzylic substituents α to the ester group which affect the half-lives of deactivation through enzymatic activity while enhancing the affinities and efficacies of individual ligands for the CB1 and CB2 receptors. The 1'-(S)-methyl, 1'-gem-dimethyl, and 1'-cyclobutyl analogues exhibit remarkably high affinities for both CB receptors. The novel ligands are susceptible to enzymatic hydrolysis by plasma esterases in a controllable manner, while their metabolites are inactive at the CB receptors. In further in vitro and in vivo experiments key analogues were shown to be potent CB1 receptor agonists and to exhibit CB1-mediated hypothermic and analgesic effects.

  2. Determination of propoxur in environmental samples by automated solid-phase extraction followed by flow-injection analysis with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ruiz, Tomas [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia (Spain)]. E-mail: tpr@um.es; Martinez-Lozano, Carmen [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia (Spain); Garcia, Maria Dolores [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia (Spain)

    2007-02-19

    A sensitive method for the analysis of propoxur in environmental samples has been developed. It involves an automated solid-phase extraction (SPE) procedure using a Gilson Aspec XLi and flow-injection analysis (FI) with chemiluminescence (CL) detection. The FI-CL system relies on the photolysis of propoxur by irradiation using a low-pressure mercury lamp (main spectral line 254 nm). The resultant methylamine is subsequently detected by CL using tris(2,2'-bipyridyl)ruthenium(III), which is on-line generated by photo-oxidation of the ruthenium(II) complex in the presence of peroxydisulfate. The linear concentration range of application was 0.05-5 {mu}g mL{sup -1} of propoxur, with a detection limit of 5 ng mL{sup -1}. The repeatability was 0.82% expressed as relative standard deviation (n = 10) and the reproducibility, studied on 5 consecutive days, was 2.1%. The sample throughput was 160 injection per hour. Propoxur residues below ng mL{sup -1} levels could be determined in environmental water samples when an SPE preconcentration device was coupled on-line with the FI system. This SPE-FI-CL arrangement provides a detection limit as low as 5 ng L{sup -1} using only 500 mL of sample. In the analysis of fruits and vegetables, the detection limit was about 10 {mu}g kg{sup -1}.

  3. Determination of propoxur in environmental samples by automated solid-phase extraction followed by flow-injection analysis with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection.

    Science.gov (United States)

    Pérez-Ruiz, Tomás; Martínez-Lozano, Carmen; García, María Dolores

    2007-02-19

    A sensitive method for the analysis of propoxur in environmental samples has been developed. It involves an automated solid-phase extraction (SPE) procedure using a Gilson Aspec XLi and flow-injection analysis (FI) with chemiluminescence (CL) detection. The FI-CL system relies on the photolysis of propoxur by irradiation using a low-pressure mercury lamp (main spectral line 254 nm). The resultant methylamine is subsequently detected by CL using tris(2,2'-bipyridyl)ruthenium(III), which is on-line generated by photo-oxidation of the ruthenium(II) complex in the presence of peroxydisulfate. The linear concentration range of application was 0.05-5 microg mL(-1) of propoxur, with a detection limit of 5 ng mL(-1). The repeatability was 0.82% expressed as relative standard deviation (n=10) and the reproducibility, studied on 5 consecutive days, was 2.1%. The sample throughput was 160 injection per hour. Propoxur residues below ng mL(-1) levels could be determined in environmental water samples when an SPE preconcentration device was coupled on-line with the FI system. This SPE-FI-CL arrangement provides a detection limit as low as 5 ng L(-1) using only 500 mL of sample. In the analysis of fruits and vegetables, the detection limit was about 10 microg kg(-1).

  4. Hydrogen bonded NHO chains formed by chloranilic acid (CLA) with 4,4‧-di-t-butyl-2,2‧-bipyridyl (dtBBP) in the solid state

    Science.gov (United States)

    Bator, G.; Sawka-Dobrowolska, W.; Sobczyk, L.; Owczarek, M.; Pawlukojć, A.; Grech, E.; Nowicka-Scheibe, J.

    2012-01-01

    In crystalline state 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) forms with 4,4'-di-t-butyl-2,2'-bipyridyl (dtBBP) the hydrogen bonded chains along the b-axis. From one side of the CLA molecule the proton transfer takes place and the hydrogen bond length is very short (2.615 Å). A continuous infrared absorption is observed for dtBBP·CLA in the wavenumber range between 3100 and 800 cm -1 also indicating the strong hydrogen bonds. The DSC measurements show a weak, close to continuous, phase transition at 414 K. The complex dielectric permittivity for a single crystal sample was measured in the temperature range 100-440 K and at frequencies between 200 Hz and 2 MHz. The dielectric response is a combination of semiconducting properties and a relaxation process most probably connected with the proton dynamics in the hydrogen bonds. The mechanism of the structural phase transition is discussed.

  5. The determination of psilocin and psilocybin in hallucinogenic mushrooms by HPLC utilizing a dual reagent acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection system.

    Science.gov (United States)

    Anastos, Nicole; Lewis, Simon W; Barnett, Neil W; Sims, D Noel

    2006-01-01

    This paper describes a procedure for the determination of psilocin and psilocybin in mushroom extracts using high-performance liquid chromatography with postcolumn chemiluminescence detection. A number of extraction methods for psilocin and psilocybin in hallucinogenic mushrooms were investigated, with a simple methanolic extraction being found to be most effective. Psilocin and psilocybin were extracted from a variety of hallucinogenic mushrooms using methanol. The analytes were separated on a C12 column using a (95:5% v/v) methanol:10 mM ammonium formate, pH 3.5 mobile phase with a run time of 5 min. Detection was realized through a dual reagent chemiluminescence detection system of acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II). The chemiluminescence detection system gave improved detectability when compared with UV absorption at 269 nm, with detection limits of 1.2 x 10(-8) and 3.5 x 10(-9) mol/L being obtained for psilocin and psilocybin, respectively. The procedure was applied to the determination of psilocin and psilocybin in three Australian species of hallucinogenic mushroom.

  6. Privileged chiral ligands and catalysts

    CERN Document Server

    Zhou, Qi-Lin

    2011-01-01

    This ultimate ""must have"" and long awaited reference for every chemist working in the field of asymmetric catalysis starts with the core structure of the catalysts, explaining why a certain ligand or catalyst is so successful. It describes in detail the history, the basic structural characteristics, and the applications of these ""privileged catalysts"". A novel concept that gives readers a much deeper insight into the topic.

  7. Studies on the Local Angular Distortion and Spin Hamiltonian Parameters for the Trigonal Co2+ Center in MgCl2

    Science.gov (United States)

    Hu, Xian-Fen; Wu, Shao-Yi; Kuang, Min-Quan; Li, Guo-Liang

    2014-11-01

    The local angular distortion and spin Hamiltonian parameters (g factors g||, g⊥ and the hyperfine structure constants) for the trigonal Co2+ center in MgCl2 are theoretically studied by diagonalizing the 6×6 energy matrix of ground 4T1 state for a trigonally distorted octahedral 3d7 cluster. Based on the cluster approach, the contributions from the admixtures of various J (= 1/2;3/2;5/2) states and the ligand orbital and spin-orbit coupling interactions are taken into account in a uniform way. The local impurity-ligand bond angle in the Co2+ center is found to be about 3.44° larger than the host metal-ligand bond angle in the pure crystal due to substitution of smaller Mg2+ by bigger Co2+, inducing a further compressed ligand octahedron. The calculated spin Hamiltonian parameters using the above local angular distortion are in good agreement with the experimental data. The present studies on the local structure and the spin Hamiltonian parameters for Co2+ in MgCl2 are tentatively extended to a more general case by comparing the relevant impurity behaviours for Co2+ in various trigonal environments.

  8. Orbital angular momentum filter of photon based on spin-orbital angular momentum coupling

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dong-Xu; Zhang, Pei, E-mail: zhangpei@mail.ustc.edu.cn; Liu, Rui-Feng; Li, Hong-Rong; Gao, Hong; Li, Fu-Li

    2015-10-16

    Highlights: • We propose a scheme that can filter the orbital angular momentum of photons. • Our scheme filters the specific mode with destroying the mode. • Our scheme can theoretically filter infinity modes. • The orientation of Dove lens and HWP decides which mode will output. - Abstract: Determination of the orbital angular momentum (OAM) of vortex beams has been hotly discussed. We propose a new type of method to determine the orbital angular momentum of photons, filtering. We present an OAM filter scheme which consists of a cavity with a polarization-based Mach–Zehnder interferometer inside. Our scheme can purify the specific OAM with unitary efficiency theoretically without the pre-knowledge of the OAM spectrum of the input light. We also implemented a proof-of-principle experiment to demonstrate the feasibility of our scheme by cascading three interferometers. Our method offers a new way to determine the OAM spectrum of a light and this method can also be exploited to prepare the eigenstate of vortex beams.

  9. Orbital angular momentum filter of photon based on spin-orbital angular momentum coupling

    International Nuclear Information System (INIS)

    Highlights: • We propose a scheme that can filter the orbital angular momentum of photons. • Our scheme filters the specific mode with destroying the mode. • Our scheme can theoretically filter infinity modes. • The orientation of Dove lens and HWP decides which mode will output. - Abstract: Determination of the orbital angular momentum (OAM) of vortex beams has been hotly discussed. We propose a new type of method to determine the orbital angular momentum of photons, filtering. We present an OAM filter scheme which consists of a cavity with a polarization-based Mach–Zehnder interferometer inside. Our scheme can purify the specific OAM with unitary efficiency theoretically without the pre-knowledge of the OAM spectrum of the input light. We also implemented a proof-of-principle experiment to demonstrate the feasibility of our scheme by cascading three interferometers. Our method offers a new way to determine the OAM spectrum of a light and this method can also be exploited to prepare the eigenstate of vortex beams

  10. Radioiodinated ligands for dopamine receptors

    International Nuclear Information System (INIS)

    The dopamine receptor system is important for normal brain function; it is also the apparent action site for various neuroleptic drugs for the treatment of schizophrenia and other metal disorders. In the past few years radioiodinated ligands for single photon emission tomography (SPECT) have been successfully developed and tested in humans: [123I]TISCH for D1 dopamine receptors; [123I]IBZM, epidepride, IBF and FIDA2, four iodobenzamide derivatives, for D2/D3 dopamine receptors. In addition, [123I]β-CIT (RTI-55) and IPT, cocaine derivatives, for the dopamine reuptake site are potentially useful for diagnosis of loss of dopamine neurons. The first iodinated ligand, (R)trans-7-OH-PIPAT, for D3 dopamine receptors, was synthesized and characterized with cloned cell lines (Spodoptera frugiperda, Sf9) expressing the D2 and D3 dopamine receptors and with rat basal forebrain membrane preparations. Most of the known iodobenzamides displayed similar potency in binding to both D2 and D3 dopamine receptors expressed in the cell lines. Initial studies appear to suggest that by fine tuning the structures it may be possible to develop agents specific for D2 and D3 dopamine receptors. It is important to investigate D2/D3 selectivity for this series of potent ligands

  11. Synthesis, photophysical and preliminary investigation of the dye-sensitized solar cells properties of functionalized anthracenyl-based bipyridyl and phenanthrolyl Ru(II) complexes

    Indian Academy of Sciences (India)

    Adewale O Adeloye; Peter A Ajibade; Frances R Cummings; Lukas J Le Roux; Sampson N Mamphweli; Edson L Meyer

    2013-01-01

    Four new amphiphilic ligands: 4-(2,3-dimethylacrylic acid)-2,2'-bipyridine (L1), 4-(9-anthracenyl-10-(2,3-dimethylacrylic acid)-2,2'-bipyridine (L2), 5-(2,3-dimethylacrylic acid)-1,10-phenanthroline (L3) and 5-(9-anthracenyl-10-(2,3-dimethylacrylic acid)-1,10-phenanthroline (L4), with their corresponding homonuclear ruthenium(II) complexes formulated as cis-[Ru-(L1)3(PF6)2] (C1), cis-[Ru-(L2)3(PF6)2] (C2), cis-[Ru-(L3)3(PF6)2] (C3) and cis-[Ru-(L4)3(PF6)2] (C4), have been synthesized and characterized by elemental analysis, 1H- and 13C- NMR, FT-IR, UV-Vis and photoluminescence spectroscopy. The complexes exhibit broad and intense metal-to-ligand charge transfer (MLCT) transition bands in the visible region (400-700 nm), and red light emitting properties at room temperature. By comparison however, complexes C1 and C2 bipyridine moiety gave lower molar absorptivity coefficient at relatively similar wavelength characteristics (410-520 nm) when compared to C3 and C4 with phenanthroline based molecules. Cyclic voltammograms of the complexes revealed complex C4 with most reduction potential which might be due to increase in the conjugation of the anthracene functionalized units. Preliminary investigation of the solar cell efficiency of the complexes on TiO2 nanocrystalline films gave the best result with efficiency of 0.103% for C1 under illumination at 1000 W/m2 AM 1.5. Electrochemical impedance spectroscopy (EIS) technique however, revealed the charge transfer resistances (Rct) of the electrons on the TiO2 semiconductor.

  12. Fundamental methods to measure the orbital angular momentum of light

    NARCIS (Netherlands)

    Berkhout, Gregorius Cornelis Gerardus (Joris)

    2011-01-01

    Light is a ubiquitous carrier of information. This information can be encoded in the intensity, direction, frequency and polarisation of the light and, which was described more recently, in its orbital angular momentum. Although creating light beams with orbital angular momentum is relatively easy,

  13. Angular Momentum Phase State Representation for Quantum Pendulum

    Institute of Scientific and Technical Information of China (English)

    FAN Hong-Yi; WANG Ji-Suo

    2005-01-01

    To consummate the quantum pendulum theory whose Hamiltonian takes bosonic operator formalism and manifestly exhibits its dynamic behaviour in the entangled state representation, we introduce angular momentum state representation and phase state representation. It turns out that the angular momentum state is the partial wave expansion of the entangled state.

  14. Evolution equations for higher moments of angular momentum distributions

    CERN Document Server

    Hägler, P

    1998-01-01

    Based on a sumrule for the nucleon spin we expand quark and gluon orbital angular momentum operators and derive an evolution matrix for higher moments of the corresponding distributions. In combination with the spin-dependent DGLAP-matrix we find a complete set of spin and orbital angular momentum evolution equations.

  15. Learning web development with Bootstrap and AngularJS

    CERN Document Server

    Radford, Stephen

    2015-01-01

    Whether you know a little about Bootstrap or AngularJS, or you're a complete beginner, this book will enhance your capabilities in both frameworks and you'll build a fully functional web app. A working knowledge of HTML, CSS, and JavaScript is required to fully get to grips with Bootstrap and AngularJS.

  16. Relativistic calculations of angular dependent photoemission time delay

    CERN Document Server

    Kheifets, A S; Deshmukh, P C; Dolmatov, V K; Manson, S T

    2016-01-01

    Angular dependence of photoemission time delay for the valence $np_{3/2}$ and $np_{1/2}$ subshells of Ar, Kr and Xe is studied in the dipole relativistic random phase approximation. Strong angular anisotropy of the time delay is reproduced near respective Cooper minima while the spin-orbit splitting affects the time delay near threshold.

  17. Anomalous Magnetic Moments and Quark Orbital Angular Momentum

    OpenAIRE

    Burkardt, M.; Schnell, G.(University of the Basque Country UPV/EHU, 48080 Bilbao, Spain)

    2005-01-01

    We derive an inequality for the distribution of quarks with non-zero orbital angular momentum, and thus demonstrate, in a model-independent way, that a non-vanishing anomalous magnetic moment requires both a non-zero size of the target as well as the presence of wave function components with quark orbital angular momentum L_z>0.

  18. Quark and Gluon Orbital Angular Momentum: Where Are We?

    Science.gov (United States)

    Lorcé, Cédric; Liu, Keh-Fei

    2016-06-01

    The orbital angular momentum of quarks and gluons contributes significantly to the proton spin budget and attracted a lot of attention in the recent years, both theoretically and experimentally. We summarize the various definitions of parton orbital angular momentum together with their relations with parton distributions functions. In particular, we highlight current theoretical puzzles and give some prospects.

  19. Conservation of Orbital Angular Momentum in Stimulated Down-Conversion

    OpenAIRE

    Caetano, D. P.; Almeida, M. P.; Ribeiro, P. H. Souto; Huguenin, J. A. O.; Santos, B. Coutinho dos; Khoury, A. Z.

    2001-01-01

    We report on an experiment demonstrating the conservation of orbital angular momentum in stimulated down-conversion. The orbital angular momentum is not transferred to the individual beams of the spontaneous down-conversion, but it is conserved when twin photons are taken individually. We observe the conservation law for an individual beam of the down-conversion through cavity-free stimulated emission.

  20. Theoretical calculations, DNA interaction, topoisomerase I and phosphatidylinositol-3-kinase studies of water soluble mixed-ligand nickel(II) complexes.

    Science.gov (United States)

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Kalilur Rahiman, Aziz

    2016-03-25

    Eight water soluble mixed-ligand nickel(II) complexes of the type [NiL(1-4)(diimine)H2O]·(ClO4)2, (1-8) where L(1-4) = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen) were synthesized and characterized by elemental analysis and spectroscopic methods. The uncoordinated perchlorate anions was ascertained form IR spectra of the complexes, and the absorption spectra reveal the octahedron geometry around nickel(II) ion with tridentate Schiff base ligand, diimine and a coordinated water molecule. Cyclic voltammograms of the complexes indicate the one-electron irreversible processes in the cathodic and anodic region. In vitro antioxidant activity proved the significant radical scavenging activity of the complexes against DPPH radical. The groove/electrostatic binding nature of complexes with CT-DNA (calf thymus deoxyribonucleic acid) were affirmed by absorption, hydrodynamic and voltammetric titration experiments and docking analysis. All the complexes exhibit significant cleavage activity on plasmid DNA via hydrolytic and oxidatively, in which the oxidative mechanism involves hydroxyl radicals and supports the possibility of minor-groove binding. The complex 4 shows significant topoisomerase I (Topo-I) inhibitory activity. The molecular modeling analysis of complexes with phosphatidylinositol-3-kinase (PI3K) receptor indicate the hydrogen bonding with Met1039, Asp837 and Leu1027, and hydrophobic interactions with Ser488, Asn498, Asp500, Gln662, Lys668, Ile844, Ile847, Ile850, Val941, Leu942, Leu1020, Met1034, Leu1035, Thr1037, Met1039, Gln1041 and Ile1051 of subdomain IIA of BSA. The complexes show σ-π interaction between diimines and amino groups of Leu1030 and Arg839.

  1. Nuclear Level Density with Non-zero Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    A.N. Behkami; M. Gholami; M. Kildir; M. Soltani

    2006-01-01

    The statistical properties of interacting fermions have been studied for various angular momentum with the inclusion of pairing interaction. The dependence of the critical temperature on angular momentum for several nuclei,have been studied. The yrast energy as a function of angular momentum for 28 Si and 24Mg nuclei have been calculated up to 60.0 MeV of excitation energy. The computed limiting angular momenta are compared with the experimental results for 26Al produced by 12C + 14N reaction. The relevant nuclear level densities for non-zero angular momentum have been computed for 44Ti and l36Ba nuclei. The results are compared with their corresponding values obtained from the approximateformulas.

  2. Towards optical intensity interferometry for high angular resolution stellar astrophysics

    CERN Document Server

    Nunez, Paul D

    2012-01-01

    Most neighboring stars are still detected as point sources and are beyond the angular resolution reach of current observatories. Methods to improve our understanding of stars at high angular resolution are investigated. Air Cherenkov telescopes (ACTs), primarily used for Gamma-ray astronomy, enable us to increase our understanding of the circumstellar environment of a particular system. When used as optical intensity interferometers, future ACT arrays will allow us to detect stars as extended objects and image their surfaces at high angular resolution. Optical stellar intensity interferometry (SII) with ACT arrays, composed of nearly 100 telescopes, will provide means to measure fundamental stellar parameters and also open the possibility of model-independent imaging. A data analysis algorithm is developed and permits the reconstruction of high angular resolution images from simulated SII data. The capabilities and limitations of future ACT arrays used for high angular resolution imaging are investigated via ...

  3. Alignment of wave functions for angular momentum projection

    CERN Document Server

    Taniguchi, Yasutaka

    2016-01-01

    Angular momentum projection is used to obtain eigen states of angular momentum from general wave functions. Multi-configuration mixing calculation with angular momentum projection is an important microscopic method in nuclear physics. For accurate multi-configuration mixing calculation with angular momentum projection, concentrated distribution of $z$ components $K$ of angular momentum in the body-fixed frame ($K$-distribution) is favored. Orientation of wave functions strongly affects $K$-distribution. Minimization of variance of $\\hat{J}_z$ is proposed as an alignment method to obtain wave functions that have concentrated $K$-distribution. Benchmark calculations are performed for $\\alpha$-$^{24}$Mg cluster structure, triaxially superdeformed states in $^{40}$Ar, and Hartree-Fock states of some nuclei. The proposed alignment method is useful and works well for various wave functions to obtain concentrated $K$-distribution.

  4. Cyclic transformation of orbital angular momentum modes

    CERN Document Server

    Schlederer, Florian; Fickler, Robert; Malik, Mehul; Zeilinger, Anton

    2015-01-01

    The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D-dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D-dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally enta...

  5. Cyclic transformation of orbital angular momentum modes

    Science.gov (United States)

    Schlederer, Florian; Krenn, Mario; Fickler, Robert; Malik, Mehul; Zeilinger, Anton

    2016-04-01

    The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D-dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D-dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally entangled Bell-states.

  6. Non-gaussian CMBR angular power spectra

    CERN Document Server

    Magueijo, J

    1995-01-01

    In this paper we show how the prediction of CMBR angular power spectra C_l in non-Gaussian theories is affected by a cosmic covariance problem, that is (C_l,C_{l'}) correlations impart features on any observed C_l spectrum which are absent from the average C^l spectrum. Therefore the average spectrum is rendered a bad observational prediction, and two new prediction strategies, better adjusted to these theories, are proposed. In one we search for hidden random indices conditional to which the theory is released from the correlations. Contact with experiment can then be made in the form of the conditional power spectra plus the random index distribution. In another approach we apply to the problem a principal component analysis. We discuss the effect of correlations on the predictivity of non-Gaussian theories. We finish by showing how correlations may be crucial in delineating the borderline between predictions made by non-Gaussian and Gaussian theories. In fact, in some particular theories, correlations may ...

  7. Spatial Angular Compounding of Photoacoustic Images.

    Science.gov (United States)

    Kang, Hyun Jae; Bell, Muyinatu A Lediju; Guo, Xiaoyu; Boctor, Emad M

    2016-08-01

    Photoacoustic (PA) images utilize pulsed lasers and ultrasound transducers to visualize targets with higher optical absorption than the surrounding medium. However, they are susceptible to acoustic clutter and background noise artifacts that obfuscate biomedical structures of interest. We investigated three spatial-angular compounding methods to improve PA image quality for biomedical applications, implemented by combining multiple images acquired as an ultrasound probe was rotated about the elevational axis with the laser beam and target fixed. Compounding with conventional averaging was based on the pose information of each PA image, while compounding with weighted and selective averaging utilized both the pose and image content information. Weighted-average compounding enhanced PA images with the least distortion of signal size, particularly when there were large (i.e., 2.5 mm and 7 (°)) perturbations from the initial probe position. Selective-average compounding offered the best improvement in image quality with up 181, 1665, and 1568 times higher contrast, CNR, and SNR, respectively, compared to the mean values of individual PA images. The three presented spatial compounding methods have promising potential to enhance image quality in multiple photoacoustic applications. PMID:26890642

  8. Orbital Angular Momentum-Entanglement Frequency Transducer

    Science.gov (United States)

    Zhou, Zhi-Yuan; Liu, Shi-Long; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-09-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology, and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photon's orbital angular momentum (OAM) degrees of freedom is preferred in harnessing the information-carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 to 525 nm for OAM qubits, OAM-polarization hybrid-entangled states, and OAM-entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link between different quantum systems operating in a photon's OAM degrees of freedom, which will be of great importance in building a high-capacity OAM quantum network.

  9. Millimetre Wave with Rotational Orbital Angular Momentum

    Science.gov (United States)

    Zhang, Chao; Ma, Lu

    2016-01-01

    Orbital angular momentum (OAM) has been widely studied in fibre and short-range communications. The implementation of millimetre waves with OAM is expected to increase the communication capacity. Most experiments demonstrate the distinction of OAM modes by receiving all of the energy in the surface vertical to the radiation axis in space. However, the reception of OAM is difficult in free space due to the non-zero beam angle and divergence of energy. The reception of OAM in the space domain in a manner similar to that in optical fibres (i.e., receiving all of the energy rings vertical to the radiation axis) is impractical, especially for long-distance transmission. Here, we fabricate a prototype of the antenna and demonstrate that rather than in the space domain, the OAM can be well received in the time domain via a single antenna by rotating the OAM wave at the transmitter, i.e., the radio wave with rotational OAM. The phase and frequency measured in the experiment reveal that for different OAM modes, the received signals act as a commonly used orthogonal frequency division multiplexing (OFDM) signal in the time domain. This phase rotation has promising prospects for use in the practical reception of different OAMs of millimetre waves in long-distance transmission. PMID:27596746

  10. CLASS: The Cosmology Large Angular Scale Surveyor

    CERN Document Server

    Essinger-Hileman, Thomas; Amiri, Mandana; Appel, John W; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseley, Samuel H; Novak, Giles; Reintsema, Carl; Rostem, Karwan; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravita-tional-wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile. CLASS will survey 70\\% of the sky in four frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen to straddle the Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad frequency coverage ensures that CLASS can distinguish Galactic emission from the CMB. The sky fraction of the CLASS survey will allow the full shape of the primordial B-mode power spectrum to be characterized, including the signal from reionization at low $\\ell$. Its unique combination of large sky coverage, control of systematic errors, and high sensitivity will allow CLASS to measure or place upper limits on the tensor-to-scalar ratio at a level of $r=0.01$ and make a cosmi...

  11. CLASS: The Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Essinger-Hileman, Thomas; Ali, Aamir; Amiri, Mandana; Appel, John W.; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Gothe, Dominik; Halpern, Mark; Kogut, Alan J.; Miller, Nathan; Moseley, Samuel; Rostem, Karwan; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravitational wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile. CLASS will survey 70% of the sky in four frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen to straddle the Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad frequency coverage ensures that CLASS can distinguish Galactic emission from the CMB. The sky fraction of the CLASS survey will allow the full shape of the primordial B-mode power spectrum to be characterized, including the signal from reionization at low-length. Its unique combination of large sky coverage, control of systematic errors, and high sensitivity will allow CLASS to measure or place upper limits on the tensor-to-scalar ratio at a level of r = 0:01 and make a cosmic-variance-limited measurement of the optical depth to the surface of last scattering, tau. (c) (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  12. Orbital angular momentum divider of light

    CERN Document Server

    Dong, Hailong Zhou Jianji; Cai, Xinlun; Yu, SiYuan; Zhang, Xinliang

    2016-01-01

    Manipulation of orbital angular momentum (OAM) of light is essential in OAM-based optical systems. Especially, OAM divider, which can convert the incoming OAM mode into one or several new smaller modes in proportion at different spatial paths, is very useful in OAM-based optical networks. However, this useful tool was never reported yet. For the first time, we put forward a passive OAM divider based on coordinate transformation. The device consists of a Cartesian to log-polar coordinate converter and an inverse converter. The first converter converts the OAM light into a rectangular-shaped plane light with a transverse phase gradient. And the second converter converts the plane light into multiple diffracted light. The OAM of zeroth-order diffracted light is the product of the input OAM and the scaling parameter. The residual light is output from other diffracted orders. Furthermore, we extend the scheme to realize equal N-dividing of OAM and arbitrary dividing of OAM. The ability of dividing OAM shows huge p...

  13. Semiclassical model for attosecond angular streaking.

    Science.gov (United States)

    Smolarski, M; Eckle, P; Keller, U; Dörner, R

    2010-08-16

    Attosecond angular streaking is a new technique to achieve unsurpassed time accuracy of only a few attoseconds. Recently this has been successfully used to set an upper limit on the electron tunneling delay time in strong laser field ionization. The measurement technique can be modeled with either the time-dependent Schrödinger equation (TDSE) or a more simple semiclassical approach that describes the process in two steps in analogy to the three-step model in high harmonic generation (HHG): step one is the tunnel ionization and step two is the classical motion in the strong laser field. Here we describe in detail a semiclassical model which is based on the ADK theory for the tunneling step, with subsequent classical propagation of the electron in the laser field. We take into account different ellipticities of the laser field and a possible wavelength-dependent ellipticity that is typically observed for pulses in the two-optical-cycle regime. This semiclassical model shows excellent agreement with the experimental result. PMID:20721150

  14. Angular momentum and galaxy formation revisited

    CERN Document Server

    Romanowsky, Aaron J

    2012-01-01

    Motivated by new kinematic data in the outer parts of early-type galaxies (ETGs), we re-examine angular momentum (AM) in all galaxy types. We present methods for estimating the specific AM j, focusing on ETGs, to derive relations between stellar j_* and mass M_* (after Fall 1983). We perform analyses of 8 galaxies out to ~10 R_e, finding that data at 2 R_e are sufficient to estimate total j_*. Our results contravene suggestions that ellipticals (Es) harbor large reservoirs of hidden j_* from AM transport in major mergers. We carry out a j_*-M_* analysis of literature data for ~100 nearby bright galaxies of all types. The Es and spirals form parallel j_*-M_* tracks, which for spirals is like the Tully-Fisher relation, but for Es derives from a mass-size-rotation conspiracy. The Es contain ~3-4 times less AM than equal-mass spirals. We decompose the spirals into disks+bulges and find similar j_*-M_* trends to spirals and Es overall. The S0s are intermediate, and we propose that morphological types reflect disk/...

  15. Millimetre Wave with Rotational Orbital Angular Momentum.

    Science.gov (United States)

    Zhang, Chao; Ma, Lu

    2016-01-01

    Orbital angular momentum (OAM) has been widely studied in fibre and short-range communications. The implementation of millimetre waves with OAM is expected to increase the communication capacity. Most experiments demonstrate the distinction of OAM modes by receiving all of the energy in the surface vertical to the radiation axis in space. However, the reception of OAM is difficult in free space due to the non-zero beam angle and divergence of energy. The reception of OAM in the space domain in a manner similar to that in optical fibres (i.e., receiving all of the energy rings vertical to the radiation axis) is impractical, especially for long-distance transmission. Here, we fabricate a prototype of the antenna and demonstrate that rather than in the space domain, the OAM can be well received in the time domain via a single antenna by rotating the OAM wave at the transmitter, i.e., the radio wave with rotational OAM. The phase and frequency measured in the experiment reveal that for different OAM modes, the received signals act as a commonly used orthogonal frequency division multiplexing (OFDM) signal in the time domain. This phase rotation has promising prospects for use in the practical reception of different OAMs of millimetre waves in long-distance transmission. PMID:27596746

  16. Angular velocity and centripetal acceleration relationship

    Science.gov (United States)

    Monteiro, Martín; Cabeza, Cecilia; Marti, Arturo C.; Vogt, Patrik; Kuhn, Jochen

    2014-05-01

    During the last few years, the growing boom of smartphones has given rise to a considerable number of applications exploiting the functionality of the sensors incorporated in these devices. A sector that has unexpectedly taken advantage of the power of these tools is physics teaching, as reflected in several recent papers. In effect, the use of smartphones has been proposed in several physics experiments spanning mechanics, electromagnetism, optics, oscillations, and waves, among other subjects. Although mechanical experiments have received considerable attention, most of them are based on the use of the accelerometer. An aspect that has received less attention is the use of rotation sensors or gyroscopes. An additional advance in the use of these devices is given by the possibility of obtaining data using the accelerometer and the gyroscope simultaneously. The aim of this paper is to consider the relation between the centripetal acceleration and the angular velocity. Instead of using a formal laboratory setup, in this experiment a smartphone is attached to the floor of a merry-go-round, found in many playgrounds. Several experiments were performed with the roundabout rotating in both directions and with the smart-phone at different distances from the center. The coherence of the measurements is shown.

  17. Angular Distribution and Angular Dispersion in Collision of 19F+27A1 at 114 MeV

    Institute of Scientific and Technical Information of China (English)

    WANG Qi; Li Zhi-Chang; LU Xiu-Qin; ZHAO Kui; LIU Jian-Cheng; SERGEY Yu-Kun; DONG Yu-Chuan; LI Song-Lin; DUAN Li-Min; XU Hu-Shan; XU Hua-Gen; CHEN Ruo-Fu; WU He-Yu; HAN Jian-Long

    2004-01-01

    Angular distributions of fragments B, C, N, O, F, Ne, Na, Mg and Al induced by the collision of 19F+27 A1 at 114MeV have been measured. Angular dispersion parameters are extracted from the experimental data and compared with the theoretical ones. The dynamic dispersions for dissipative products depend strongly on the charge number Z of the fragments.

  18. Ligand placement based on prior structures: the guided ligand-replacement method

    Energy Technology Data Exchange (ETDEWEB)

    Klei, Herbert E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Moriarty, Nigel W., E-mail: nwmoriarty@lbl.gov; Echols, Nathaniel [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Terwilliger, Thomas C. [Los Alamos National Laboratory, Los Alamos, NM 87545-0001 (United States); Baldwin, Eric T. [Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Natural Discovery LLC, Princeton, NJ 08542-0096 (United States); Pokross, Matt; Posy, Shana [Bristol-Myers Squibb, Princeton, NJ 08543-4000 (United States); Adams, Paul D. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); University of California at Berkeley, Berkeley, CA 94720-1762 (United States)

    2014-01-01

    A new module, Guided Ligand Replacement (GLR), has been developed in Phenix to increase the ease and success rate of ligand placement when prior protein-ligand complexes are available. The process of iterative structure-based drug design involves the X-ray crystal structure determination of upwards of 100 ligands with the same general scaffold (i.e. chemotype) complexed with very similar, if not identical, protein targets. In conjunction with insights from computational models and assays, this collection of crystal structures is analyzed to improve potency, to achieve better selectivity and to reduce liabilities such as absorption, distribution, metabolism, excretion and toxicology. Current methods for modeling ligands into electron-density maps typically do not utilize information on how similar ligands bound in related structures. Even if the electron density is of sufficient quality and resolution to allow de novo placement, the process can take considerable time as the size, complexity and torsional degrees of freedom of the ligands increase. A new module, Guided Ligand Replacement (GLR), was developed in Phenix to increase the ease and success rate of ligand placement when prior protein–ligand complexes are available. At the heart of GLR is an algorithm based on graph theory that associates atoms in the target ligand with analogous atoms in the reference ligand. Based on this correspondence, a set of coordinates is generated for the target ligand. GLR is especially useful in two situations: (i) modeling a series of large, flexible, complicated or macrocyclic ligands in successive structures and (ii) modeling ligands as part of a refinement pipeline that can automatically select a reference structure. Even in those cases for which no reference structure is available, if there are multiple copies of the bound ligand per asymmetric unit GLR offers an efficient way to complete the model after the first ligand has been placed. In all of these applications, GLR

  19. Antimicrobial mechanism of copper (II 1,10-phenanthroline and 2,2′-bipyridyl complex on bacterial and fungal pathogens

    Directory of Open Access Journals (Sweden)

    S. Chandraleka

    2014-12-01

    Full Text Available Copper based metallo drugs were prepared and their antibacterial, antifungal, molecular mechanism of [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O complexes were investigated. The [Cu(SAlaPhen]·H2O and [Cu(SAlabpy]·H2O were derived from the Schiff base alanine salicylaldehyde. [Cu(SAlaPhen]·H2O showed noteworthy antibacterial and antifungal activity than the [Cu(SAlabpy]·H2O and ligand alanine, salicylaldehyde. The [Cu(SAlaPhen]·H2O complex showed significant antibacterial activity against Salmonella typhi, Staphylococcus aureus, Salmonella paratyphi and the antifungal activity against Candida albicans and Cryptococcus neoformans in well diffusion assay. The mode of action of copper (II complex was analyzed by DNA cleavage activity and in silico molecular docking. The present findings provide important insight into the molecular mechanism of copper (II complexes in susceptible bacterial and fungal pathogens. These results collectively support the use of [Cu(SAlaPhen]·H2O complex as a suitable drug to treat bacterial and fungal infections.

  20. The origin of angular momentum in dark matter halos

    CERN Document Server

    Vitvitska, M; Kravtsov, A V; Bullock, J S; Wechsler, R H; Primack, Joel R

    2002-01-01

    We propose a new explanation for the origin of angular momentum in galaxies and their dark halos, in which the halos obtain their spin through the cumulative acquisition of angular momentum from satellite accretion. In our model, the build-up of angular momentum is a random walk process associated with the mass assembly history of the halo's major progenitor. We assume no correlation between the angular momenta of accreted objects. Using the extended Press-Schechter approximation, we calculate the growth of mass, angular momentum, and spin parameter $\\lambda$ for many halos. Our random walk model reproduces the key features of the angular momentum of halos found in N-body simulations: a lognormal distribution in $\\lambda$ with an average of $ \\approx 0.04$, independent of mass and redshift. The evolution of the spin parameter in individual halos in this model is quite different from the steady increase with time of angular momentum in the tidal torque picture. We find both in N-body simulations and in our ran...

  1. Angular dependent light emission from planar waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Peter, Jaison, E-mail: jaison.peter@gmail.com [International School of Photonics, Cochin University of Science and Technology, Cochin 682022 (India); CRE" +E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ (United Kingdom); Prabhu, Radhakrishna [CRE" +E, IDEAS Research Institute, Robert Gordon University, Aberdeen AB10 7GJ (United Kingdom); Radhakrishnan, P.; Vallabhan, C. P. G.; Nampoori, V. P. N.; Kailasnath, M. [International School of Photonics, Cochin University of Science and Technology, Cochin 682022 (India)

    2015-01-07

    We have investigated the angular dependence of amplified spontaneous emission (ASE) and laser emission from an asymmetric and free-standing polymer thin films doped with rhodamine 6G, which is transversely pumped by a pulsed Nd:YAG laser. A semi-leaky waveguide or quasi-waveguide structure has been developed by spin coating technique. In these waveguides, the light was confined by the film/air-film/glass substrate interfaces. At the film/substrate interface, a portion of light will reflect back into the film (guided mode) and the remaining refracted to the substrate resulting in cutoff modes. A blue-shift in ASE has been observed when the pump power was increased from 8 to 20 mW allowing a limited range of tuning of emission wavelength. To study the directionality of the ASE from the waveguide, we have measured the output intensity and FWHM of emission spectra as a function of viewing angle (θ) from the plane parallel to film. From the detailed examination of the output emission spectra, as +θ increases from 0° there has been an initial decrease in output intensity, but at a particular angle ≈10° an increase in output intensity was observed. This additional peak in output intensity as +θ is a clear indication of coexistence of the cutoff mode. We also present a compact solid-state laser based on leaky mode propagation from the dye-doped polymer free-standing film (∼50 μm thickness) waveguide. The partial reflections from the broad lateral surfaces of the free-standing films provided the optical feedback for the laser emission with high directionality. For a pump power of 22 mW, an intense line with FWHM <0.2 nm was observed at 578 nm.

  2. Knee abduction angular impulses during prolonged running with wedged insoles.

    Science.gov (United States)

    Lewinson, Ryan T; Worobets, Jay T; Stefanyshyn, Darren J

    2013-07-01

    Wedged insoles may produce immediate effects on knee abduction angular impulses during running; however, it is currently not known whether these knee abduction angular impulse magnitudes are maintained throughout a run when fatigue sets in. If changes occur, this could affect the clinical utility of wedged insoles in treating conditions such as patellofemoral pain. Thus, the purpose of this study was to determine whether knee abduction angular impulses are altered during a prolonged run with wedged insoles. It was hypothesized that knee abduction angular impulses would be reduced following a prolonged run with wedged insoles. Nine healthy runners participated. Runners were randomly assigned to either a 6-mm medial wedge condition or a 6-mm lateral wedge condition and then ran continuously overground for 30 min. Knee abduction angular impulses were quantified at 0 and 30 min using a gait analysis procedure. After 2 days, participants returned to perform the same test but with the other wedge type. Two-way repeated-measures analysis of variance was used to evaluate main effects of wedge condition and time and interactions between wedge condition and time (α = 0.05). Paired t-tests were used for post hoc analysis (α = 0.01). No interaction effects (p = 0.958) were found, and knee abduction angular impulses were not significantly different over time (p = 0.384). Lateral wedge conditions produced lesser knee abduction angular impulses than medial conditions at 0 min (difference of 2.79 N m s, p = 0.006) and at 30 min (difference of 2.76 N m s, p < 0.001). It is concluded that significant knee abduction angular impulse changes within wedge conditions do not occur during a 30-min run. Additionally, knee abduction angular impulse differences between wedge conditions are maintained during a 30-min run.

  3. Ligand photo-isomerization triggers conformational changes in iGluR2 ligand binding domain.

    Directory of Open Access Journals (Sweden)

    Tino Wolter

    Full Text Available Neurological glutamate receptors bind a variety of artificial ligands, both agonistic and antagonistic, in addition to glutamate. Studying their small molecule binding properties increases our understanding of the central nervous system and a variety of associated pathologies. The large, oligomeric multidomain membrane protein contains a large and flexible ligand binding domains which undergoes large conformational changes upon binding different ligands. A recent application of glutamate receptors is their activation or inhibition via photo-switchable ligands, making them key systems in the emerging field of optochemical genetics. In this work, we present a theoretical study on the binding mode and complex stability of a novel photo-switchable ligand, ATA-3, which reversibly binds to glutamate receptors ligand binding domains (LBDs. We propose two possible binding modes for this ligand based on flexible ligand docking calculations and show one of them to be analogues to the binding mode of a similar ligand, 2-BnTetAMPA. In long MD simulations, it was observed that transitions between both binding poses involve breaking and reforming the T686-E402 protein hydrogen bond. Simulating the ligand photo-isomerization process shows that the two possible configurations of the ligand azo-group have markedly different complex stabilities and equilibrium binding modes. A strong but slow protein response is observed after ligand configuration changes. This provides a microscopic foundation for the observed difference in ligand activity upon light-switching.

  4. Generation and detection of orbital angular momentum via metasurface

    Science.gov (United States)

    Jin, Jinjin; Luo, Jun; Zhang, Xiaohu; Gao, Hui; Li, Xiong; Pu, Mingbo; Gao, Ping; Zhao, Zeyu; Luo, Xiangang

    2016-04-01

    Beams carrying orbital angular momentum possess a significant potential for modern optical technologies ranging from classical and quantum communication to optical manipulation. In this paper, we theoretically design and experimentally demonstrate an ultracompact array of elliptical nanoholes, which could convert the circularly polarized light into the cross-polarized vortex beam. To measure the topological charges of orbital angular momentum in a simple manner, another elliptical nanoholes array is designed to generate reference beam as a reference light. This approach may provide a new way for the generation and detection of orbital angular momentum in a compact device.

  5. Coherent detection of orbital angular momentum in radio

    CERN Document Server

    Daldorff, L K S; Bergman, J E S; Isham, B; Al-Nuaimi, M K T; Forozesh, K; Carozzi, T D

    2015-01-01

    The angular momentum propagated by a beam of radiation has two contributions: spin angular momentum (SAM) and orbital angular momentum (OAM). SAM corresponds to wave polarisation, while OAM-carrying beams are characterized by a phase which is a function of azimuth. We demonstrate experimentally that radio beams propagating OAM can be generated and coherently detected using ordinary electric dipole antennas. The results presented here could pave the way for novel radio OAM applications in technology and science, including radio communication, passive remote sensing, and new types of active (continuous or pulsed transmission) electromagnetic measurements.

  6. Angular magnetoresistance in semiconducting undoped amorphous carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sagar, Rizwan Ur Rehman; Saleemi, Awais Siddique; Zhang, Xiaozhong, E-mail: xzzhang@tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People' s Republic of China and Beijing National Center for Electron Microscopy, Beijing 100084 (China)

    2015-05-07

    Thin films of undoped amorphous carbon thin film were fabricated by using Chemical Vapor Deposition and their structure was investigated by using High Resolution Transmission Electron Microscopy and Raman Spectroscopy. Angular magnetoresistance (MR) has been observed for the first time in these undoped amorphous carbon thin films in temperature range of 2 ∼ 40 K. The maximum magnitude of angular MR was in the range of 9.5% ∼ 1.5% in 2 ∼ 40 K. The origin of this angular MR was also discussed.

  7. Induced Compression of White Dwarfs by Angular Momentum Loss

    CERN Document Server

    Boshkayev, Kuantay; Ruffini, Remo; Zhami, Bakytzhan

    2016-01-01

    We investigate isolated sub- and super-Chandrasekhar white dwarfs which lose angular momentum through magnetic dipole braking. We construct constant rest mass sequences by fulfilling all stability criteria of rotating configurations and show how the main structure of white dwarfs such as the central density, mean radius and angular velocity change with time. We explicitly demonstrate that all isolated white dwarfs regardless of their masses, by angular momentum loss, shrink and increase their central density. We also analyze the effects of the structure parameters on the evolution timescale both in the case of constant magnetic field and constant magnetic flux.

  8. Notes on the quantum theory of angular momentum

    CERN Document Server

    Feenberg, Eugene

    1999-01-01

    This classic, concise text has served a generation of physicists as an exceptionally useful guide to the mysteries of angular momenta and Clebsch-Gordon Coefficients. Derived from notes originally prepared to assist graduate students in reading research papers on atomic, molecular, and nuclear structure, the text first reviews the basic elements of quantum theory. It then examines the development of the fundamental commutation relations for angular momentum components and vector operators, and the ways in which matrix elements and eigenvalues of the angular momentum operators are worked out f

  9. Electro-optic analyzer of angular momentum hyperentanglement.

    Science.gov (United States)

    Wu, Ziwen; Chen, Lixiang

    2016-02-25

    Characterizing a high-dimensional entanglement is fundamental in quantum information applications. Here, we propose a theoretical scheme to analyze and characterize the angular momentum hyperentanglement that two photons are entangled simultaneously in spin and orbital angular momentum. Based on the electro-optic sampling with a proposed hyper-entanglement analyzer and the simple matrix operation using Cramer rule, our simulations show that it is possible to retrieve effectively both the information about the degree of polarization entanglement and the spiral spectrum of high-dimensional orbital angular momentum entanglement.

  10. Detection of a spinning object using light's orbital angular momentum.

    Science.gov (United States)

    Lavery, Martin P J; Speirits, Fiona C; Barnett, Stephen M; Padgett, Miles J

    2013-08-01

    The linear Doppler shift is widely used to infer the velocity of approaching objects, but this shift does not detect rotation. By analyzing the orbital angular momentum of the light scattered from a spinning object, we observed a frequency shift proportional to product of the rotation frequency of the object and the orbital angular momentum of the light. This rotational frequency shift was still present when the angular momentum vector was parallel to the observation direction. The multiplicative enhancement of the frequency shift may have applications for the remote detection of rotating bodies in both terrestrial and astronomical settings.

  11. Generation and detection of orbital angular momentum via metasurface.

    Science.gov (United States)

    Jin, Jinjin; Luo, Jun; Zhang, Xiaohu; Gao, Hui; Li, Xiong; Pu, Mingbo; Gao, Ping; Zhao, Zeyu; Luo, Xiangang

    2016-04-07

    Beams carrying orbital angular momentum possess a significant potential for modern optical technologies ranging from classical and quantum communication to optical manipulation. In this paper, we theoretically design and experimentally demonstrate an ultracompact array of elliptical nanoholes, which could convert the circularly polarized light into the cross-polarized vortex beam. To measure the topological charges of orbital angular momentum in a simple manner, another elliptical nanoholes array is designed to generate reference beam as a reference light. This approach may provide a new way for the generation and detection of orbital angular momentum in a compact device.

  12. Control of Angular Intervals for Angle-Multiplexed Holographic Memory

    Science.gov (United States)

    Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki

    2009-03-01

    In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

  13. Generation and detection of orbital angular momentum via metasurface.

    Science.gov (United States)

    Jin, Jinjin; Luo, Jun; Zhang, Xiaohu; Gao, Hui; Li, Xiong; Pu, Mingbo; Gao, Ping; Zhao, Zeyu; Luo, Xiangang

    2016-01-01

    Beams carrying orbital angular momentum possess a significant potential for modern optical technologies ranging from classical and quantum communication to optical manipulation. In this paper, we theoretically design and experimentally demonstrate an ultracompact array of elliptical nanoholes, which could convert the circularly polarized light into the cross-polarized vortex beam. To measure the topological charges of orbital angular momentum in a simple manner, another elliptical nanoholes array is designed to generate reference beam as a reference light. This approach may provide a new way for the generation and detection of orbital angular momentum in a compact device. PMID:27052796

  14. The pretzelosity TMD and quark orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Lorce, C. [IPNO, Universite Paris-Sud, CNRS/IN2P3, 91406 Orsay (France); LPT, Universite Paris-Sud, CNRS, 91406 Orsay (France); Pasquini, B., E-mail: pasquini@pv.infn.it [Dipartimento di Fisica, Universita degli Studi di Pavia, Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia (Italy)

    2012-04-12

    We study the connection between the quark orbital angular momentum and the pretzelosity transverse-momentum dependent parton distribution function. We discuss the origin of this relation in quark models, identifying as key ingredient for its validity the assumption of spherical symmetry for the nucleon in its rest frame. Finally we show that the individual quark contributions to the orbital angular momentum obtained from this relation cannot be interpreted as the intrinsic contributions, but include the contribution from the transverse centre of momentum which cancels out only in the total orbital angular momentum.

  15. Experimental Evidence for Partonic Orbital Angular Momentum at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Douglas E. [University of New Mexico, Department of Physics and Astronomy, Albuquerque, NM 871331 (United States)

    2011-12-14

    Although one might naively anticipate that the proton, being the lowest baryonic energy state, would be in a L = 0 state, the current theoretical understanding is that it must carry orbital angular momentum in order, for example, to have a non-zero anomalous magnetic moment. I will review the experimental evidence linked theoretically to orbital angular momentum of the proton's constituents from the RHIC experiments and summarize by presenting a challenge to the theory community--to develop a consistent framework which can explain the spin polarization asymmetries seen at RHIC and elsewhere, and give insight to the partonic wave-functions including orbital angular momentum.

  16. Femtosecond dynamics of spin and orbital angular momentum in nickel

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, Christian; Pontius, Niko; Holldack, Karsten; Quast, Torsten; Kachel, Torsten; Wietstruk, Marko; Mitzner, Rolf; Duerr, Hermann A. [Elektronenspeicherring BESSY II, Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, 12489 Berlin (Germany)

    2009-07-01

    At the BESSY femtoslicing source we measure X-ray magnetic circular dichroism (XMCD) with 100 fs time resolution. By virtue of the XMCD sum rules, we find that the spin and orbital momenta in a thin nickel film are quenched with a time constant of 150 fs upon excitation with a fs laser pulse. This represents the first unambiguous proof that the total electronic angular momentum is transferred to the lattice on the same ultrafast time scale. The quenching of orbital angular momentum also is a serious constraint for models of angular momentum dissipation.

  17. Angular correlation of electrons and positrons in internal pair conversion

    International Nuclear Information System (INIS)

    The angular distribution of electrons and positrons which are emitted in internal pair conversion (IPC) is calculated. Coulomb-distorted waves are used as electron wave functions. Nuclear transitions of various multipolarities L>0 and of magnetic (ML) and electric (EL) type are considered as well as E0-conversion. Analytical expressions for the angular correlation are derived which are evaluated numerically assuming a finite extension of the nucleus and, for the EL and ML conversion, also in point-nucleus approximation. The calculated angular correlations are compared with results obtained within the Born approximation and, for the E0 case, with experimental data. (orig.)

  18. MEASUREMENT OF ANGULAR VIBRATION AMPLITUDE BY ACTIVELY BLURRED IMAGES

    Institute of Scientific and Technical Information of China (English)

    GUAN Baiqing; WANG Shigang; LIU Chong; LI Qian

    2007-01-01

    A novel motion-blur-based method for measuring the angular amplitude of a high-frequency rotational vibration is schemed. The proposed approach combines the active vision concept and the mechanism of motion-from-blur, generates motion blur on the image plane actively by extending exposure time, and utilizes the motion blur information in polar images to estimate the angular amplitude of a high-frequency rotational vibration. This method obtains the analytical results of the angular vibration amplitude from the geometric moments of a motion blurred polar image and an unblurred image for reference. Experimental results are provided to validate the presented scheme.

  19. Ruthenium Cumulenylidene Complexes Bearing Heteroscorpionate Ligands

    OpenAIRE

    Strinitz, Frank

    2014-01-01

    In previous work of the BURZLAFF group, the design of suitable N,N,O ligands for a wide variety of applications ranging from catalysis to bioinorganic model compounds has been extensively investigated. Especially the methyl substituted bis(3,5-dimethylpyrazol-1-yl) acetate (bdmpza) ligand has shown manifold chemistry, comparable to the anionic cyclopentadienyl (Cp) and hydridotris(pyrazol-1-yl)borato (Tp) ligand. In the first part of this thesis the new tricarbonylmanganese(I) complexes be...

  20. Clinical Use of PPARγ Ligands in Cancer

    Directory of Open Access Journals (Sweden)

    Jennifer L. Hatton

    2008-01-01

    Full Text Available The role of PPARγ in adipocyte differentiation has fueled intense interest in the function of this steroid nuclear receptor for regulation of malignant cell growth and differentiation. Given the antiproliferative and differentiating effects of PPARγ ligands on liposarcoma cells, investigation of PPARγ expression and ligand activation in other solid tumors such as breast, colon, and prostate cancers ensued. The anticancer effects of PPARγ ligands in cell culture and rodent models of a multitude of tumor types suggest broad applicability of these agents to cancer therapy. This review focuses on the clinical use of PPARγ ligands, specifically the thiazolidinediones, for the treatment and prevention of cancer.

  1. Hydrogen bonded NHO chains formed by chloranilic acid (CLA) with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP) in the solid state

    International Nuclear Information System (INIS)

    Graphical abstract: The molecular complex dtBBP·CLA, its crystal structure at 100 K, infrared, the DFT calculations, a phase transition at ca. 414 K, DSC, dielectric response analysis, proton dynamics, antiferroelectric properties. Highlights: ► We synthesized a novel molecular complex, dtBBP·CLA. ► We determined the crystal structure of dtBBP·CLA at 100 K. ► We detected a phase transition at 414 K in the complex and postulated its mechanism. ► We interpreted the infrared spectra of dtBBP·CLA. ► We used DFT to calculate the molecular structure of dtBBP·CLA in solid state. - Abstract: In crystalline state 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) forms with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP) the hydrogen bonded chains along the b-axis. From one side of the CLA molecule the proton transfer takes place and the hydrogen bond length is very short (2.615 Å). A continuous infrared absorption is observed for dtBBP·CLA in the wavenumber range between 3100 and 800 cm−1 also indicating the strong hydrogen bonds. The DSC measurements show a weak, close to continuous, phase transition at 414 K. The complex dielectric permittivity for a single crystal sample was measured in the temperature range 100–440 K and at frequencies between 200 Hz and 2 MHz. The dielectric response is a combination of semiconducting properties and a relaxation process most probably connected with the proton dynamics in the hydrogen bonds. The mechanism of the structural phase transition is discussed.

  2. Pluto Moons exhibit Orbital Angular Momentum Quantization per Mass

    OpenAIRE

    Potter F.

    2012-01-01

    The Pluto satellite system of the planet plus five moons is shown to obey the quan- tum celestial mechanics (QCM) angular momentum per mass quantization condition predicted for any gravitationally bound system.

  3. Coriolis effects are principally caused by gyroscopic angular acceleration.

    Science.gov (United States)

    Isu, N; Yanagihara, M; Mikuni, T; Koo, J

    1994-07-01

    A cause of nausea evoked by cross-coupled rotation (termed Coriolis stimulus) was determined. Subjects were provided with two types of cross-coupled rotations: neck-forward flexion (Neck Flx) and upper body-forward flexion (Body Flx) during horizontal whole body rotation at a constant angular velocity. These Coriolis stimuli were given alternatively in an experimental sequence, and the severity of the nausea they evoked was compared by the subjects. The results indicated that the same quality of nausea was evoked by a slightly higher angular velocity during Body Flx (100.5 degrees/s) than during Neck Flx (90 degrees/s). While Body Flx generated Coriolis linear acceleration several times larger than Neck Flx, both the stimuli generated a similar magnitude of gyroscopic angular acceleration in this condition. Therefore, it was inferred that the nausea evoked by a Coriolis stimulus is principally caused by gyroscopic angular acceleration.

  4. Imaging the Earth's Interior: the Angular Distribution of Terrestrial Neutrinos

    CERN Document Server

    Fields, Brian D

    2004-01-01

    Decays of radionuclides throughout the Earth's interior produce geothermal heat, but also are a source of antineutrinos. The (angle-integrated) geoneutrino flux places an integral constraint on the terrestrial radionuclide distribution. In this paper, we calculate the angular distribution of geoneutrinos, which opens a window on the differential radionuclide distribution. We develop the general formalism for the neutrino angular distribution, and we present the inverse transformation which recovers the terrestrial radioisotope distribution given a measurement of the neutrino angular distribution. Thus, geoneutrinos not only allow a means to image the Earth's interior, but offering a direct measure of the radioactive Earth, both (1) revealing the Earth's inner structure as probed by radionuclides, and (2) allowing for a complete determination of the radioactive heat generation as a function of radius. We present the geoneutrino angular distribution for the favored Earth model which has been used to calculate g...

  5. Pluto Moons exhibit Orbital Angular Momentum Quantization per Mass

    Directory of Open Access Journals (Sweden)

    Potter F.

    2012-10-01

    Full Text Available The Pluto satellite system of the planet plus five moons is shown to obey the quan- tum celestial mechanics (QCM angular momentum per mass quantization condition predicted for any gravitationally bound system.

  6. Uncertainty Relation between Angular Momentum and Angle Variable.

    Science.gov (United States)

    Roy, C. L.; Sannigrahi, A. B.

    1979-01-01

    Discusses certain pitfalls regarding the uncertainty relation between angular momentum and the angle variable from a pedagogic point of view. Further, an uncertainty relation has been derived for these variables in a simple and consistant manner. (Author/HM)

  7. Effect of angular momentum conservation on hydrodynamic simulations of colloids.

    Science.gov (United States)

    Yang, Mingcheng; Theers, Mario; Hu, Jinglei; Gompper, Gerhard; Winkler, Roland G; Ripoll, Marisol

    2015-07-01

    In contrast to most real fluids, angular momentum is not a locally conserved quantity in some mesoscopic simulation methods. Here we quantify the importance of this conservation in the flow fields associated with different colloidal systems. The flow field is analytically calculated with and without angular momentum conservation for the multiparticle collision dynamics (MPC) method, and simulations are performed to verify the predictions. The flow field generated around a colloidal particle moving under an external force with slip boundary conditions depends on the conservation of angular momentum, and the amplitude of the friction force is substantially affected. Interestingly, no dependence on the angular momentum conservation is found for the flow fields generated around colloids under the influence of phoretic forces. Moreover, circular Couette flow between a no-slip and a slip cylinder is investigated, which allows us to validate one of the two existing expressions for the MPC stress tensor.

  8. Orbital angular momentum in optical waves propagating through distributed turbulence.

    Science.gov (United States)

    Sanchez, Darryl J; Oesch, Denis W

    2011-11-21

    This is the second of two papers demonstrating that photons with orbital angular momentum can be created in optical waves propagating through distributed turbulence. In the companion paper, it is shown that propagation through atmospheric turbulence can create non-trivial angular momentum. Here, we extend the result and demonstrate that this momentum is, at least in part, orbital angular momentum. Specifically, we demonstrate that branch points (in the language of the adaptive optic community) indicate the presence of photons with non-zero OAM. Furthermore, the conditions required to create photons with non-zero orbital angular momentum are ubiquitous. The repercussions of this statement are wide ranging and these are cursorily enumerated.

  9. Relevance of angular momentum conservation in mesoscale hydrodynamics simulations.

    Science.gov (United States)

    Götze, Ingo O; Noguchi, Hiroshi; Gompper, Gerhard

    2007-10-01

    The angular momentum is conserved in fluids with a few exceptions such as ferrofluids. However, it can be violated locally in fluid simulations to reduce computational costs. The effects of this violation are investigated using a particle-based simulation method, multiparticle collision dynamics, which can switch on or off angular-momentum conservation. To this end, we study circular Couette flows between concentric and eccentric cylinders, where nonphysical torques due to the lack of the angular-momentum conservation are found whereas the velocity field is not affected. In addition, in simulations of fluids with different viscosities in contact and star polymers in solvent, incorrect angular velocities occur. These results quantitatively agree with the theoretical predictions based on the macroscopic stress tensor.

  10. General covariant conservative angular momentum as internal charges

    Institute of Scientific and Technical Information of China (English)

    赵德品

    1996-01-01

    The usual approach to internal conservative charges is used to obtain the conservation laws of angular-momentum in both Einstein gravity and gravitational anyons.The results are in complete agreement with those of references.

  11. Design and Implementation of a Digital Angular Rate Sensor

    Directory of Open Access Journals (Sweden)

    Zhen Peng

    2010-10-01

    Full Text Available With the aim of detecting the attitude of a rotating carrier, the paper presents a novel, digital angular rate sensor. The sensor consists of micro-sensing elements (gyroscope and accelerometer, signal processing circuit and micro-processor (DSP2812. The sensor has the feature of detecting three angular rates of a rotating carrier at the same time. The key techniques of the sensor, including sensing construction, sensing principles, and signal processing circuit design are presented. The test results show that the sensor can sense rolling, pitch and yaw angular rate at the same time and the measurement error of yaw (or pitch angular rate and rolling rate of the rotating carrier is less than 0.5%.

  12. Stellar Diameters and Temperatures IV. Predicting Stellar Angular Diameters

    CERN Document Server

    Boyajian, Tabetha; von Braun, Kaspar

    2013-01-01

    The number of stellar angular diameter measurements has greatly increased over the past few years due to innovations and developments in the field of long baseline optical interferometry (LBOI). We use a collection of high-precision angular diameter measurements for nearby, main-sequence stars to develop empirical relations that allow the prediction of stellar angular sizes as a function of observed photometric color. These relations are presented for a combination of 48 broad-band color indices. We empirically show for the first time a dependence on metallicity to these relations using Johnson $(B-V)$ and Sloan $(g-r)$ colors. Our relations are capable of predicting diameters with a random error of less than 5% and represent the most robust and empirical determinations to stellar angular sizes to date.

  13. Phase-space distributions and orbital angular momentum

    Directory of Open Access Journals (Sweden)

    Pasquini B.

    2014-06-01

    Full Text Available We review the concept of Wigner distributions to describe the phase-space distributions of quarks in the nucleon, emphasizing the information encoded in these functions about the quark orbital angular momentum.

  14. Electronic orbital angular momentum and magnetism of graphene

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Ji, E-mail: ji.luo@upr.edu

    2014-10-01

    Orbital angular momentum (OAM) of graphene electrons in a perpendicular magnetic field is calculated and corresponding magnetic moment is used to investigate the magnetism of perfect graphene. Variation in magnetization demonstrates its decrease with carrier-doping, plateaus in a large field, and de Haas–van Alphen oscillation. Regulation of graphene's magnetism by a parallel electric field is presented. The OAM originates from atomic-scale electronic motion in graphene lattice, and vector hopping interaction between carbon atomic orbitals is the building element. A comparison between OAM of graphene electrons, OAM of Dirac fermions, and total angular momentum of the latter demonstrates their different roles in graphene's magnetism. Applicability and relation to experiments of the results are discussed. - Highlights: • Orbital angular momentum of graphene electrons is calculated. • Orbital magnetic moment of graphene electrons is obtained. • Variation in magnetization of graphene is calculated. • Roles of different kinds of angular momentum are investigated.

  15. Phase-space distributions and orbital angular momentum

    OpenAIRE

    Pasquini B.; Lorcé C.

    2014-01-01

    We review the concept of Wigner distributions to describe the phase-space distributions of quarks in the nucleon, emphasizing the information encoded in these functions about the quark orbital angular momentum.

  16. Electronic orbital angular momentum and magnetism of graphene

    International Nuclear Information System (INIS)

    Orbital angular momentum (OAM) of graphene electrons in a perpendicular magnetic field is calculated and corresponding magnetic moment is used to investigate the magnetism of perfect graphene. Variation in magnetization demonstrates its decrease with carrier-doping, plateaus in a large field, and de Haas–van Alphen oscillation. Regulation of graphene's magnetism by a parallel electric field is presented. The OAM originates from atomic-scale electronic motion in graphene lattice, and vector hopping interaction between carbon atomic orbitals is the building element. A comparison between OAM of graphene electrons, OAM of Dirac fermions, and total angular momentum of the latter demonstrates their different roles in graphene's magnetism. Applicability and relation to experiments of the results are discussed. - Highlights: • Orbital angular momentum of graphene electrons is calculated. • Orbital magnetic moment of graphene electrons is obtained. • Variation in magnetization of graphene is calculated. • Roles of different kinds of angular momentum are investigated

  17. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    CERN Document Server

    Chuss, D T; Amiri, M; Appel, J; Bennett, C L; Colazo, F; Denis, K L; Dünner, R; Essinger-Hileman, T; Eimer, J; Fluxa, P; Gothe, D; Halpern, M; Harrington, K; Hilton, G; Hinshaw, G; Hubmayr, J; Iuliano, J; Marriage, T A; Miller, N; Moseley, S H; Mumby, G; Petroff, M; Reintsema, C; Rostem, K; U-Yen, K; Watts, D; Wagner, E; Wollack, E J; Xu, Z; Zeng, L

    2015-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe $\\sim$70% of the sky. A variable-delay polarization modulator (VPM) modulates the polarization at $\\sim$10 Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that span both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously d...

  18. Differential reflective fiber-optic angular displacement sensor

    Science.gov (United States)

    Shan, Mingguang; Min, Rui; Zhong, Zhi; Wang, Ying; Zhang, Yabin

    2015-05-01

    Using the characteristic that the distance apart between the emitting fiber and receiving fiber only shifts the angular-power curve, a differential reflective fiber-optic sensor for angular displacement measurement is presented through subtraction of two power signals from two receiving fibers placed on both sides of one emitting fiber. A theoretical model is established to characterize the performance of the differential reflective fiber-optic angular displacement sensor. The measurements made indicate that the general behavior of the experimental results agrees with that of the theoretical results, and the sensor can improve sensitivity by about 120%, resulting in the significant improvement of anti-interference capability, which will be more suitable for high accuracy bipolar absolute angular displacement measurement. Design guidelines are also suggested to achieve desired sensor performances.

  19. Quantum optimal control of photoelectron spectra and angular distributions

    CERN Document Server

    Goetz, R Esteban; Santra, Robin; Koch, Christiane P

    2016-01-01

    Photoelectron spectra and photoelectron angular distributions obtained in photoionization reveal important information on e.g. charge transfer or hole coherence in the parent ion. Here we show that optimal control of the underlying quantum dynamics can be used to enhance desired features in the photoelectron spectra and angular distributions. To this end, we combine Krotov's method for optimal control theory with the time-dependent configuration interaction singles formalism and a splitting approach to calculate photoelectron spectra and angular distributions. The optimization target can account for specific desired properties in the photoelectron angular distribution alone, in the photoelectron spectrum, or in both. We demonstrate the method for hydrogen and then apply it to argon under strong XUV radiation, maximizing the difference of emission into the upper and lower hemispheres, in order to realize directed electron emission in the XUV regime.

  20. Quantum optimal control of photoelectron spectra and angular distributions

    Science.gov (United States)

    Goetz, R. Esteban; Karamatskou, Antonia; Santra, Robin; Koch, Christiane P.

    2016-01-01

    Photoelectron spectra and photoelectron angular distributions obtained in photoionization reveal important information on, e.g., charge transfer or hole coherence in the parent ion. Here we show that optimal control of the underlying quantum dynamics can be used to enhance desired features in the photoelectron spectra and angular distributions. To this end, we combine Krotov's method for optimal control theory with the time-dependent configuration interaction singles formalism and a splitting approach to calculate photoelectron spectra and angular distributions. The optimization target can account for specific desired properties in the photoelectron angular distribution alone, in the photoelectron spectrum, or in both. We demonstrate the method for hydrogen and then apply it to argon under strong XUV radiation, maximizing the difference of emission into the upper and lower hemispheres, in order to realize directed electron emission in the XUV regime.

  1. All joint moments significantly contribute to trunk angular acceleration.

    Science.gov (United States)

    Nott, Cameron R; Zajac, Felix E; Neptune, Richard R; Kautz, Steven A

    2010-09-17

    Computationally advanced biomechanical analyses of gait demonstrate the often counter-intuitive roles of joint moments on various aspects of gait such as propulsion, swing initiation, and balance. Each joint moment can produce linear and angular acceleration of all body segments (including those on which the moment does not directly act) due to the dynamic coupling inherent in the interconnected musculoskeletal system. This study presents quantitative relationships between individual joint moments and trunk control with respect to balance during gait to show that the ankle, knee, and hip joint moments all affect the angular acceleration of the trunk. We show that trunk angular acceleration is affected by all joints in the leg with varying degrees of dependence during the gait cycle. Furthermore, it is shown that inter-planar coupling exists and a two-dimensional analysis of trunk balance neglects important out-of-plane joint moments that affect trunk angular acceleration.

  2. Fabrication of the planar angular rotator using the CMOS process

    Science.gov (United States)

    Dai, Ching-Liang; Chang, Chien-Liu; Chen, Hung-Lin; Chang, Pei-Zen

    2002-05-01

    In this investigation we propose a novel planar angular rotator fabricated by the conventional complementary metal-oxide semiconductor (CMOS) process. Following the 0.6 μm single poly triple metal (SPTM) CMOS process, the device is completed by a simple maskless, post-process etching step. The rotor of the planar angular rotator rotates around its geometric center with electrostatic actuation. The proposed design adopts an intelligent mechanism including the slider-crank system to permit simultaneous motion. The CMOS planar angular rotator could be driven with driving voltages of around 40 V. The design proposed here has a shorter response time and longer life, without problems of friction and wear, compared to the more common planar angular micromotor.

  3. "Angle" Operator Conjugate to Photon's Intrinsic Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    范洪义

    2001-01-01

    We find the correct "angle" operator conjugate to the intrinsic angular momentum of the photon by introducing a suitable representation which involves both left-handed and right-handed polarization photon operators.

  4. Generation and detection of orbital angular momentum via metasurface

    OpenAIRE

    Jin, Jinjin; Luo, Jun; Zhang, Xiaohu; Gao, Hui; Li, Xiong; Pu, Mingbo; Gao, Ping; Zhao, Zeyu; Luo, Xiangang

    2016-01-01

    Beams carrying orbital angular momentum possess a significant potential for modern optical technologies ranging from classical and quantum communication to optical manipulation. In this paper, we theoretically design and experimentally demonstrate an ultracompact array of elliptical nanoholes, which could convert the circularly polarized light into the cross-polarized vortex beam. To measure the topological charges of orbital angular momentum in a simple manner, another elliptical nanoholes a...

  5. The angular momentum of baryons and dark matter halos revisited

    OpenAIRE

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole....

  6. Angular momentum and torque described with the complex octonion

    OpenAIRE

    Zi-Hua Weng

    2014-01-01

    The paper aims to adopt the complex octonion to formulate the angular momentum, torque, and force etc in the electromagnetic and gravitational fields. Applying the octonionic representation enables one single definition of angular momentum (or torque, force) to combine some physics contents, which were considered to be independent of each other in the past. J. C. Maxwell used simultaneously two methods, the vector terminology and quaternion analysis, to depict the electromagnetic theory. It m...

  7. Comparison between two concepts of angular glint:general considerations

    Institute of Scientific and Technical Information of China (English)

    Wang Chao; Yin Hongcheng; Huang Peikang

    2008-01-01

    Angular glint can be interpreted as a distortion of the radar echo signal phase front,or alternatively,a tilt of the direction of energy flow from the radial direction.As the complementarities and support of argumentation in our previous work,a general discussion about two concepts of angular glint is made based on electromagnetic theory to demonstrate that these two concepts are equivalent when geometrical optics approximation is used and the receiving antenna is linearly polarized.

  8. Relaxation times for angular momentum in damped nuclear reactions

    International Nuclear Information System (INIS)

    The evolution of the angular momentum distribution in damped nuclear reactions is discussed within the framework of the nucleon exchange transport model. First order equations are derived for the time evolution of the mean values and covariances of the spin variables. Solutions are given for 1400 MeV 165Ho + 165Ho reactions at various values of total angular momentum and total kinetic energy loss. Spin dispersions are well described by the calculations

  9. Students' Understanding of the Addition of Angular Momentum

    CERN Document Server

    Singh, Chandralekha

    2016-01-01

    We describe the difficulties advanced undergraduate and graduate students have with concepts related to the addition of angular momentum. We also describe the development and implementation of a research-based learning tool, a Quantum Interactive Learning Tutorial (QuILT), to reduce these difficulties. The preliminary evaluation shows that the QuILT on the addition of angular momentum is helpful in improving students' understanding of these concepts.

  10. Asymmetry in the angular distributions of spectator-nucleons

    International Nuclear Information System (INIS)

    The asymmetry in the angular distributions of spectator-nucleons has been studied in dp interactions, and it has been found that the sign of the asymmetry depends on the reaction channel. It is shown that in the momentum interval 0-200 MeV/c of spectators basic features of the angular distributions can be reproduced in the framework of the spectator model taking into account the energy dependence of the NN cross section and the flux-factor

  11. Alignment of angular velocity sensors for a vestibular prosthesis

    OpenAIRE

    DiGiovanna Jack; Carpaneto Jacopo; Micera Silvestro; Merfeld Daniel M

    2012-01-01

    Abstract Vestibular prosthetics transmit angular velocities to the nervous system via electrical stimulation. Head-fixed gyroscopes measure angular motion, but the gyroscope coordinate system will not be coincident with the sensory organs the prosthetic replaces. Here we show a simple calibration method to align gyroscope measurements with the anatomical coordinate system. We benchmarked the method with simulated movements and obtain proof-of-concept with one healthy subject. The method was r...

  12. Alignment of angular velocity sensors for a vestibular prosthesis.

    Science.gov (United States)

    Digiovanna, Jack; Carpaneto, Jacopo; Micera, Silvestro; Merfeld, Daniel M

    2012-01-01

    Vestibular prosthetics transmit angular velocities to the nervous system via electrical stimulation. Head-fixed gyroscopes measure angular motion, but the gyroscope coordinate system will not be coincident with the sensory organs the prosthetic replaces. Here we show a simple calibration method to align gyroscope measurements with the anatomical coordinate system. We benchmarked the method with simulated movements and obtain proof-of-concept with one healthy subject. The method was robust to misalignment, required little data, and minimal processing. PMID:22329908

  13. Angular velocity nonlinear observer from single vector measurements

    OpenAIRE

    Magnis, Lionel; Petit, Nicolas

    2015-01-01

    The paper proposes a technique to estimate the angular velocity of a rigid body from single vector measurements. Compared to the approaches presented in the literature, it does not use attitude information nor rate gyros as inputs. Instead, vector measurements are directly filtered through a nonlinear observer estimating the angular velocity. Convergence is established using a detailed analysis of a linear-time varying dynamics appearing in the estimation error equation. This equation stems f...

  14. Mechanical Faraday effect for orbital angular momentum-carrying beams

    OpenAIRE

    Wisniewski-Barker, Emma; Gibson, Graham; Franke-Arnold, Sonja; Boyd, Robert W; Padgett, Miles J.

    2014-01-01

    When linearly polarised light is transmitted through a spinning window, the plane of polarisation is rotated. This rotation arises through a phase change that is applied to the circularly polarised states corresponding to the spin angular momentum (SAM). Here we show an analogous effect for the orbital angular momentum (OAM), where a differential phase between the positive and negative modes (±ℓ) is observed as a rotation of the transmitted image. For normal materials, this rotation is on the...

  15. A quantum memory for orbital angular momentum photonic qubits

    OpenAIRE

    Nicolas, A; Veissier, L.; Giner, L.; Giacobino, E.; Maxein, D.; Laurat, J.

    2013-01-01

    Among the optical degrees of freedom, the orbital angular momentum of light provides unique properties, including mechanical torque action with applications for light manipulation, enhanced sensitivity in imaging techniques and potential high-density information coding for optical communication systems. Recent years have also seen a tremendous interest in exploiting orbital angular momentum at the single-photon level in quantum information technologies. In this endeavor, here we demonstrate t...

  16. Fundamental methods to measure the orbital angular momentum of light

    OpenAIRE

    Berkhout, Gregorius Cornelis Gerardus (Joris)

    2011-01-01

    Light is a ubiquitous carrier of information. This information can be encoded in the intensity, direction, frequency and polarisation of the light and, which was described more recently, in its orbital angular momentum. Although creating light beams with orbital angular momentum is relatively easy, measuring this property has proven to be difficult. In this thesis we present two fundamental methods to solve this problem. First, we show that by analysing the interference pattern behind a multi...

  17. Spin-to-Orbital Angular Momentum Conversion in Semiconductor Microcavities

    OpenAIRE

    Manni, Francesco; Lagoudakis, Konstantinos G.; Paraïso, Taofiq; Cerna, Roland; Léger, Yoan; Liew, Timothy Chi Hin; Shelykh, Ivan; Kavokin, Alexey V.; Morier-Genoud, François; Deveaud-Plédran, Benoît

    2011-01-01

    We experimentally demonstrate a technique for the generation of optical beams carrying orbital angular momentum using a planar semiconductor microcavity. Despite being isotropic systems with no structural gyrotropy, semiconductor microcavities, because of the transverse-electric–transverse-magnetic polarization splitting that they feature, allow for the conversion of the circular polarization of an incoming laser beam into the orbital angular momentum of the transmitted light field. The proce...

  18. Orbital Angular Momentum and Generalized Transverse Momentum Distribution

    OpenAIRE

    Zhao, Yong; Liu, Keh-Fei; Yang, Yibo

    2015-01-01

    We show that, when boosted to the infinite momentum frame, the quark and gluon orbital angular momentum operators defined in the nucleon spin sum rule of X. S. Chen et al. are the same as those derived from generalized transverse momentum distributions. This completes the connection between the infinite momentum limit of each term in that sum rule and experimentally measurable observables. We also show that these orbital angular momentum operators can be defined locally, and discuss the strat...

  19. Total Internal Reflection of Orbital Angular Momentum Beams

    OpenAIRE

    Loffler W.; Hermosa N.; Aiello A.; Woerdman J.P.

    2012-01-01

    We investigate how beams with orbital angular momentum (OAM) behave under total internal reflection. This is studied in two complementary experiments: In the first experiment, we study geometric shifts of OAM beams upon total internal reflection (Goos-H\\"anchen and Imbert-Fedorov shifts, for each the spatial and angular variant), and in the second experiment we determine changes in the OAM mode spectrum of a beam, again upon total internal reflection. As a result we find that in the first cas...

  20. Relativistic electron ring equilibrium with angular momentum spread

    Energy Technology Data Exchange (ETDEWEB)

    Croitoru, M.; Grecu, D. (Institutul de Fizica si Inginerie Nucleara, Bucharest (Romania))

    1980-01-01

    The equilibrium properties of a relativistic electron ring are determined by solving in a consistent way the Vlasov-Maxwell equations for a distribution function with an angular momentum spread. In the thin ring approximation there have been deduced general formulae for the electron density and the current density. A general theorem concerning the sharp form in space of the electron density is also obtained for the case of a microcanonical distribution function both in energy and angular momentum.

  1. Asymmetric angular dependence of domain wall motion in magnetic nanowires.

    Science.gov (United States)

    Nam, Chunghee

    2013-03-01

    An angular dependence of domain wall (DW) motion is studied in a magnetic wire consisting of a giant-magnetoresistance spin-valve. A DW pinning site is formed by a single notch, where a conventional linear one and a specially designed tilted one are compared. The asymmetric angular dependence was found in the DW depinning behavior with the tilted notch. The geometry control of the pinning site can be useful for DW diode devices using a rotating magnetic field. PMID:23755619

  2. Modelling black holes with angular momentum in loop quantum gravity

    Science.gov (United States)

    Frodden, Ernesto; Perez, Alejandro; Pranzetti, Daniele; Röken, Christian

    2014-12-01

    We construct a connection formulation of Kerr isolated horizons. As in the non-rotating case, the model is based on a Chern-Simons theory describing the degrees of freedom on the horizon. The presence of a non-vanishing angular momentum modifies the admissibility conditions for spin network states. Physical states of the system are in correspondence with open intertwiners with total spin matching the angular momentum of the spacetime.

  3. Topological defects, geometric phases, and the angular momentum of light

    CERN Document Server

    Tiwari, S C

    2007-01-01

    Recent reports on the intriguing features of vector vortex bearing beams are analyzed using geometric phases in optics. It is argued that the spin redirection phase induced circular birefringence is the origin of topological phase singularities arising in the inhomogeneous polarization patterns. A unified picture of recent results is presented based on this proposition. Angular momentum shift within the light beam (OAM) has exact equivalence with the angular momentum holonomy associated with the geometric phase consistent with our conjecture.

  4. A Role for Improved Angular Observations in Geosynchronous Orbit Determination

    Science.gov (United States)

    Sabol, Christopher Andrew

    1998-12-01

    The goal of this thesis is to show that improved angular observations can aid in the determination of satellite position and velocity in the geosynchronous orbit regime. Raven is a new sensor being developed by the U.S. Air Force Research Laboratory which should allow for angular observations of satellites to be made with a standard deviation of 1 arcsecond (which maps into approximately 170 meters at geosynchronous altitude); this is an order of magnitude improvement over traditional angular observation techniques and represents state of the art accuracy of angular observations for geosynchronous orbit determination work. Simulation studies are undertaken to show that these angular observations can be used in the orbit determination process both as the only cracking data source and as a supplement to other tracking data sources such as radar and radio transponder ranges. Results from the radio transponder range analysis are extended to cover Satellite Laser Ranging (SLR) and Global Positioning System (GPS) observation types as well. The studies target both space surveillance and owner/operator mission support aspects of orbit determination although the emphasis will be on mission support satellite operations. Parameters varied in the simulation studies include the number of observing stations, the density of the angular observations, and the number of nights of optical tracking. The data simulations are calibrated based on real data results from a geosynchronous satellite to ensure the integrity of the simulations and the accuracy of the results. The studies show that including the improved angular observations with traditional high accuracy range observations produces a significant improvement in orbit determination accuracy over the range observations alone. The studies also show single site geosynchronous orbit determination is an attractive alternative when combining improved angular and high accuracy range observations.

  5. Angular Impulse and Balance Regulation During the Golf Swing.

    Science.gov (United States)

    Peterson, Travis J; Wilcox, Rand R; McNitt-Gray, Jill L

    2016-08-01

    Our aim was to determine how skilled players regulate linear and angular impulse while maintaining balance during the golf swing. Eleven highly-skilled golf players performed swings with a 6-iron and driver. Components contributing to linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force [RFh], RFh-angle, and moment arm) were quantified and compared across the group and within a player (α = .05). Net angular impulse generated by both the rear and target legs was greater for the driver than the 6-iron. Mechanisms used to regulate angular impulse generation between clubs varied across players and required coordination between the legs. Increases in net angular impulse with a driver involved increases in target leg RFh. Rear leg RFh-angle was maintained between clubs whereas target leg RFh became more aligned with the target line. Net linear impulse perpendicular to the target line remained near zero, preserving balance, while net linear impulse along the target line decreased in magnitude. These results indicate that the net angular impulse was regulated between clubs by coordinating force generation of the rear and target legs while sustaining balance throughout the task. PMID:26958870

  6. Angular-velocity control approach for stance-control orthoses.

    Science.gov (United States)

    Lemaire, Edward D; Goudreau, Louis; Yakimovich, Terris; Kofman, Jonathan

    2009-10-01

    Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma. PMID:19497821

  7. Macrocyclic ligands for uranium complexation

    International Nuclear Information System (INIS)

    A highly preorganized 24-macrocycle containing biuret, thiobiuret and pyridine subunits has been prepared by high dilution ring-closure procedures. Intermediate products to this macrocycle have been utilized to extend this synthetic route to include further representatives where solubility and stability will be influenced by substituent variation. A 1:1 complex has been formed from uranyl acetate and a quinquepyridine derivative, this representing a new type of ligand for the uranyl ion. A very convenient synthetic procedure that will allow the incorporation of these macrocycles into polymeric systems has been developed for the introduction of a vinyl substituent into the 4-position of the pyridine ring. Using triflate, vinyltributyltin and Pd0 chemistry, this procedure should make a variety of substituted 4-vinylpyridines available for the first time. 3 refs

  8. Synthesis and characterization of mixed ligand chiral nanoclusters

    OpenAIRE

    Güven, Zekiye Pelin; Guven, Zekiye Pelin; Üstbaş, Burçin; Ustbas, Burcin; Harkness, Kellen M.; Coşkun, Hikmet; Coskun, Hikmet; Joshi, Chakra P.; Besong, Tabot M. D.; Stellacci, Francesco; Bakr, Osman M.; Akbulut, Özge; Akbulut, Ozge

    2015-01-01

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. The ratio of the ligands was changed to track the formation of these clusters. While the chiral ligand lead to nanoparticles, Presence of the achiral ligand induced the formation of nanoclusters with chiral properties.

  9. Rhodium olefin complexes of diiminate type ligands

    NARCIS (Netherlands)

    Willems, Sander Theodorus Hermanus

    2003-01-01

    The mono-anionic beta-diiminate ligand (ArNC(CH3)CHC(CH3)NAr) on several previous occasions proved useful in stabilising low coordination numbers for both early and late transition metals. In this thesis the reactivity of the rhodium olefin complexes of one of these beta-diiminate ligands (Ar = 2,6-

  10. Flexible Ligand Docking Using Differential Evolution

    DEFF Research Database (Denmark)

    Thomsen, René

    2003-01-01

    the most favorable energetic conformation among the large space of possible protein-ligand complexes. Stochastic search methods, such as evolutionary algorithms (EAs), can be used to sample large search spaces effectively and is one of the preferred methods for flexible ligand docking. The differential...

  11. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  12. Smoothed dissipative particle dynamics with angular momentum conservation

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Kathrin, E-mail: k.mueller@fz-juelich.de; Fedosov, Dmitry A., E-mail: d.fedosov@fz-juelich.de; Gompper, Gerhard, E-mail: g.gompper@fz-juelich.de

    2015-01-15

    Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier–Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor–Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.

  13. Measurement of angular velocity in the perception of rotation.

    Science.gov (United States)

    Barraza, José F; Grzywacz, Norberto M

    2002-09-01

    Humans are sensitive to the parameters of translational motion, namely, direction and speed. At the same time, people have special mechanisms to deal with more complex motions, such as rotations and expansions. One wonders whether people may also be sensitive to the parameters of these complex motions. Here, we report on a series of experiments that explore whether human subjects can use angular velocity to evaluate how fast a rotational motion is. In four experiments, subjects were required to perform a task of speed-of-rotation discrimination by comparing two annuli of different radii in a temporal 2AFC paradigm. Results showed that humans could rely on a sensitive measurement of angular velocity to perform this discrimination task. This was especially true when the quality of the rotational signal was high (given by the number of dots composing the annulus). When the signal quality decreased, a bias towards linear velocity of 5-80% appeared, suggesting the existence of separate mechanisms for angular and linear velocity. This bias was independent from the reference radius. Finally, we asked whether the measurement of angular velocity required a rigid rotation, that is, whether the visual system makes only one global estimate of angular velocity. For this purpose, a random-dot disk was built such that all the dots were rotating with the same tangential speed, irrespectively of radius. Results showed that subjects do not estimate a unique global angular velocity, but that they perceive a non-rigid disk, with angular velocity falling inversely proportionally with radius. PMID:12367744

  14. Polarization control of single photon quantum orbital angular momentum states.

    Science.gov (United States)

    Nagali, E; Sciarrino, F; De Martini, F; Piccirillo, B; Karimi, E; Marrucci, L; Santamato, E

    2009-10-12

    The orbital angular momentum of photons, being defined in an infinite-dimensional discrete Hilbert space, offers a promising resource for high-dimensional quantum information protocols in quantum optics. The biggest obstacle to its wider use is presently represented by the limited set of tools available for its control and manipulation. Here, we introduce and test experimentally a series of simple optical schemes for the coherent transfer of quantum information from the polarization to the orbital angular momentum of single photons and vice versa. All our schemes exploit a newly developed optical device, the so-called "q-plate", which enables the manipulation of the photon orbital angular momentum driven by the polarization degree of freedom. By stacking several q-plates in a suitable sequence, one can also have access to higher-order angular momentum subspaces. In particular, we demonstrate the control of the orbital angular momentum m degree of freedom within the subspaces of |m| = 2h and |m| = 4h per photon.

  15. The angular momentum of baryons and dark matter halos revisited

    CERN Document Server

    Kimm, Taysun; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r=0.1rvir. In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/rvir>0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its ...

  16. Angular response of alanine samples: From powder to pellet

    International Nuclear Information System (INIS)

    Alanine radicals produced by irradiation can be observed through the ESR measurement of powder or in a pellet with an angular response. There are five main peaks in the ESR alanine spectrum. Usually, the central peak amplitude (A1) is chosen to perform dose measurements because it is the largest. Looking at the angular response it seems that the peak amplitude (A2) shows lower maximal deviation and standard deviations. The angular response exists from the first step of the process as powder through the granular form until the final compact pellet form. Results about the angular response on pure alanine powders and its evolution during the manufacturing process of homemade pellets, as well as commercial pellets from different suppliers are presented. The evolution of the angular response with time gives information about the stability of radicals. The manufacturing process of pellet also influences the stabilization of the radicals produced by irradiation; therefore pellet reproducibility. This study raises questions and makes proposals for a better approach to reduce measurement uncertainties for high and low doses measurements

  17. Is the angular momentum of an electron conserved in a uniform magnetic field?

    Science.gov (United States)

    Greenshields, Colin R; Stamps, Robert L; Franke-Arnold, Sonja; Barnett, Stephen M

    2014-12-12

    We show that an electron moving in a uniform magnetic field possesses a time-varying "diamagnetic" angular momentum. Surprisingly this means that the kinetic angular momentum of the electron may vary with time, despite the rotational symmetry of the system. This apparent violation of angular momentum conservation is resolved by including the angular momentum of the surrounding fields.

  18. A Computational Technique to Determine the Angular Displacement, Velocity and Momentum of a Human Body.

    Science.gov (United States)

    Hay, James G.; Wilson, Barry D.

    The angular momentum of a human body derived from both the angular velocity and angular displacement, utilizing cinematographic records has not been adequately assessed, prior to this study. Miller (1970) obtained the angular momentum but only during the airborne phase of activity. The method used by Ramey (1973) involved a force platform, but…

  19. Coordinate unsaturation with fluorinated ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rack, J.L.; Hurlburt, P.K.; Anderson, O.P.; Strauss, S.H. [Colorado State Univ., Ft. Collins, CO (United States)

    1993-12-31

    The preparation and characterization of Zn(OTeF{sub 5}){sub 2} has resulted in a model compound with which to explore the concept of coordinative unsaturation. The coordination of solvents of varying donicity and dielectric constant to the Zn(II) ions in Zn(OTeF{sub 5}){sub 2} was studied by vapor phase monometry, NMR and IR spectroscopy, conductimetry, and X-Ray crystallography. The structures of [Zn(C{sub 6}H{sub 5}NO{sub 2}){sub 2}(OTeF{sub 5})2]2 and Zn(C{sub 6}H{sub 5}NO{sub 2}){sub 3}(OTEF{sub 5}){sub 2} demonstrate the electronic flexibility of some weakly coordinating solvents in that nitrobenzene can function as either an {eta}{sup 1}O or {eta}{sup 2}O,O`-ligand. The dependence of the number of bound solvent molecules and the degree of OTeF{sub 5}{minus} dissociation on solvent donor number and dielectric constant will be presented.

  20. Orbital angular momentum of scalar field generated by gravitational scatterings

    CERN Document Server

    Nishikawa, Ryusuke; Masuda, Atsuki; Nambu, Yasusada; Ishihara, Hideki

    2016-01-01

    It has been expected that astronomical observations to detect the orbital angular momenta of electromagnetic waves may give us a new insight into astrophysics. Previous works pointed out the possibility that a rotating black hole can produce orbital angular momenta of electromagnetic waves through gravitational scattering, and the spin parameter of the black hole can be measured by observing them. However, the mechanism how the orbital angular momentum of the electromagnetic wave is generated by the gravitational scattering has not been clarified sufficiently. In this paper, in order to understand it from a point of view of gravitational lensing effects, we consider an emitter which radiates a spherical wave of the real massless scalar field and study the deformation of the scalar wave by the gravitational scattering due to a black hole by invoking the geometrical optics approximation. We show that the frame dragging caused by the rotating black hole is not a necessary condition for generating the orbital ang...

  1. Free falling and rising of spherical and angular particles

    Science.gov (United States)

    Rahmani, M.; Wachs, A.

    2014-08-01

    Direct numerical simulations of freely falling and rising particles in an infinitely long domain, with periodic lateral boundary conditions, are performed. The focus is on characterizing the free motion of cubical and tetrahedral particles for different Reynolds numbers, as an extension to the well-studied behaviour of freely falling and rising spherical bodies. The vortical structure of the wake, dynamics of particle movement, and the interaction of the particle with its wake are studied. The results reveal mechanisms of path instabilities for angular particles, which are different from those for spherical ones. The rotation of the particle plays a more significant role in the transition to chaos for angular particles. Following a framework similar to that of Mougin and Magnaudet ["Wake-induced forces and torques on a zigzagging/spiralling bubble," J. Fluid Mech. 567, 185-194 (2006)], the balance of forces and torques acting on particles is discussed to gain more insight into the path instabilities of angular particles.

  2. Transfer of optical orbital angular momentum to a bound electron

    Science.gov (United States)

    Schmiegelow, Christian T.; Schulz, Jonas; Kaufmann, Henning; Ruster, Thomas; Poschinger, Ulrich G.; Schmidt-Kaler, Ferdinand

    2016-10-01

    Photons can carry angular momentum, not only due to their spin, but also due to their spatial structure. This extra twist has been used, for example, to drive circular motion of microscopic particles in optical tweezers as well as to create vortices in quantum gases. Here we excite an atomic transition with a vortex laser beam and demonstrate the transfer of optical orbital angular momentum to the valence electron of a single trapped ion. We observe strongly modified selection rules showing that an atom can absorb two quanta of angular momentum from a single photon: one from the spin and another from the spatial structure of the beam. Furthermore, we show that parasitic ac-Stark shifts from off-resonant transitions are suppressed in the dark centre of vortex beams. These results show how light's spatial structure can determine the characteristics of light-matter interaction and pave the way for its application and observation in other systems.

  3. A quantum memory for orbital angular momentum photonic qubits

    Science.gov (United States)

    Nicolas, A.; Veissier, L.; Giner, L.; Giacobino, E.; Maxein, D.; Laurat, J.

    2014-03-01

    Among the optical degrees of freedom, the orbital angular momentum of light provides unique properties, including mechanical torque action, which has applications for light manipulation, enhanced sensitivity in imaging techniques and potential high-density information coding for optical communication systems. Recent years have also seen a tremendous interest in exploiting orbital angular momentum at the single-photon level in quantum information technologies. In pursuing this endeavour, we demonstrate here the implementation of a quantum memory for quantum bits encoded in this optical degree of freedom. We generate various qubits with computer-controlled holograms, store and retrieve them on demand using a dynamic electromagnetically induced transparency protocol. We further analyse the retrieved states by quantum tomography and thereby demonstrate fidelities exceeding the classical benchmark, confirming the quantum functioning of our storage process. Our results provide an essential capability for future networks exploring the promises of orbital angular momentum of photons for quantum information applications.

  4. New representation of orbital motion with arbitrary angular momenta

    CERN Document Server

    Suzuki, Y; Varga, K

    1997-01-01

    A new formulation is presented for a variational calculation of $N$-body systems on a correlated Gaussian basis with arbitrary angular momenta. The rotational motion of the system is described with a single spherical harmonic of the total angular momentum $L$, and thereby needs no explicit coupling of partial waves between particles. A simple generating function for the correlated Gaussian is exploited to derive the matrix elements. The formulation is applied to various Coulomb three-body systems such as $e^-e^-e^+, tt\\mu, td\\mu$, and $\\alpha e^-e^-$ up to $L=4$ in order to show its usefulness and versatility. A stochastic selection of the basis functions gives good results for various angular momentum states.

  5. Probing angular momentum coherence in a twin-atom interferometer

    CERN Document Server

    de Carvalho, Carlos R; Impens, François; Robert, J; Medina, Aline; Zappa, F; Faria, N V de Castro

    2014-01-01

    We propose to use a double longitudinal Stern-Gerlach atom interferometer in order to investigate quantitatively the angular momentum coherence of molecular fragments. Assuming that the dissociated molecule has a null total angular momentum, we investigate the propagation of the corresponding atomic fragments in the apparatus. We show that the envisioned interferometer enables one to distinguish unambiguously a spin-coherent from a spin-incoherent dissociation, as well as to estimate the purity of the angular momentum density matrix associated with the fragments. This setup, which may be seen as an atomic analogue of a twin-photon interferometer, can be used to investigate the suitability of molecule dissociation processes -- such as the metastable hydrogen atoms H($2^2 S$)-H($2^2 S$) dissociation - for coherent twin-atom optics.

  6. Polarization angular spectra of Galactic synchrotron emission on arcminute scales

    CERN Document Server

    Tucci, M; Cecchini, S; Nicastro, L; Fabbri, R; Gaensler, B M; Dickey, J M; McClure-Griffiths, N M

    2002-01-01

    We study the angular power spectra of the polarized component of the Galactic synchrotron emission in the 28-deg^2 Test Region of the Southern Galactic Plane Survey at 1.4 GHz. These data were obtained by the Australia Telescope Compact Array and allow us to investigate angular power spectra down to arcminute scales. We find that, at this frequency, the polarization spectra for E- and B-modes seem to be affected by Faraday rotation produced in compact foreground screens. A different behavior is shown by the angular spectrum of the polarized intensity PI=\\sqrt{Q^2+U^2}. This is well fitted by a power law with slope \\~1.7, which agrees with higher frequency results and can probably be more confidently extrapolated to the cosmological window.

  7. A Differential Reflective Intensity Optical Fiber Angular Displacement Sensor.

    Science.gov (United States)

    Jia, Binghui; He, Lei; Yan, Guodong; Feng, Yong

    2016-09-16

    In this paper, a novel differential reflective intensity optical fiber angular displacement sensor was proposed. This sensor can directly measure the angular and axial linear displacement of a flat surface. The structure of the sensor probe is simple and its basic principle was first analyzed according to the intensity modulation mechanisms. Secondly, in order to trim the dark output voltage to zero, the photoelectric conversion circuit was developed to adjust the signals. Then, the sensor model including the photoelectric conversion circuit has been established, and the influence of design parameters on the sensor output characteristic has been simulated. Finally, the design parameters of the sensor structure were obtained based on the simulation results; and an experimental test system was built for the sensor calibration. Experimental results show that the linear angular range and the sensitivity of the sensor were 74.4 and 0.051 V/°, respectively. Its change rules confirm the operating principle of the sensor well.

  8. Valley-contrasting orbital angular momentum in photonic valley crystals

    CERN Document Server

    Chen, Xiaodong; Dong, Jianwen

    2016-01-01

    Valley, as a degree of freedom, has been exploited to realize valley-selective Hall transport and circular dichroism in two-dimensional layered materials. On the other hand, orbital angular momentum of light with helical phase distribution has attracted great attention for its unprecedented opportunity to optical communicagtions, atom trapping, and even nontrivial topology engineering. Here, we reveal valley-contrasting orbital angular momentum in all-dielectric photonic valley crystals. Selective excitation of valley chiral bulk states is realized by sources carrying orbital angular momentum with proper chirality. Valley dependent edge states, predictable by nonzero valley Chern number, enable to suppress the inter-valley scattering along zigzag boundary, leading to broadband robust transmission in Z-shape bend without corner morphological optimization. Our work may open up a new door towards the discovery of novel quantum states and the manipulation of spin-orbit interaction of light in nanophotonics.

  9. Conservation of orbital angular momentum in air core optical fibers

    CERN Document Server

    Gregg, P; Ramachandran, S

    2014-01-01

    Light's orbital angular momentum (OAM) is a conserved quantity in cylindrically symmetric media; however, it is easily destroyed by free-space turbulence or fiber bends, because anisotropic perturbations impart angular momentum. We observe the conservations of OAM even in the presence of strong bend perturbations, with fibers featuring air cores that appropriately sculpt the modal density of states. In analogy to the classical reasoning for the enhanced stability of spinning tops with increasing angular velocity, these states' lifetimes with OAM magnitude. Consequently, contrary to convention wisdom that ground states of systems are the most stable, OAM longevity in air-core fiber increases with mode order. Aided by conservation of this fundamental quantity, we demonstrate fiber propagation of 12 distinct higher-order OAM modes, of which 8 remain low-loss and >98% pure from near-degenerate coupling after km-length propagation. The first realization of long-lived higher-order OAM states, thus far posited to ex...

  10. Absolute angular calibration of a submarine km3 neutrino telescope

    International Nuclear Information System (INIS)

    A requirement for neutrino telescope is the ability to resolve point sources of neutrinos. In order to understand its resolving power a way to perform absolute angular calibration with muons is required. Muons produced by cosmic rays in the atmosphere offer an abundant calibration source. By covering a surface vessel with 200 modules of 5 m2 plastic scintillator a surface air shower array can be set up. Running this array in coincidence with a deep-sea km3 size neutrino detector, where the coincidence is defined by the absolute clock timing stamp for each event, would allow absolute angular calibration to be performed. Monte Carlo results simulating the absolute angular calibration of the km3 size neutrino detector will be presented. Future work and direction will be discussed.

  11. Fractional angular momentum in cold-atom systems.

    Science.gov (United States)

    Zhang, Yuhe; Sreejith, G J; Gemelke, N D; Jain, J K

    2014-10-17

    The quantum statistics of bosons or fermions are manifest through the even or odd relative angular momentum of a pair. We show theoretically that, under certain conditions, a pair of certain test particles immersed in a fractional quantum Hall state possesses, effectively, a fractional relative angular momentum, which can be interpreted in terms of fractional braid statistics. We propose that the fractionalization of the angular momentum can be detected directly through the measurement of the pair correlation function in rotating ultracold atomic systems in the fractional quantum Hall regime. Such a measurement will also provide direct evidence for the effective magnetic field resulting from Berry phases arising from attached vortices, and of excitations with a fractional particle number, analogous to the fractional charge of the electron fractional quantum Hall effect.

  12. On-chip noninterference angular momentum multiplexing of broadband light.

    Science.gov (United States)

    Ren, Haoran; Li, Xiangping; Zhang, Qiming; Gu, Min

    2016-05-13

    Angular momentum division has emerged as a physically orthogonal multiplexing method in high-capacity optical information technologies. However, the typical bulky elements used for information retrieval from the overall diffracted field, based on the interference method, impose a fundamental limit toward realizing on-chip multiplexing. We demonstrate noninterference angular momentum multiplexing by using a mode-sorting nanoring aperture with a chip-scale footprint as small as 4.2 micrometers by 4.2 micrometers, where nanoring slits exhibit a distinctive outcoupling efficiency on tightly confined plasmonic modes. The nonresonant mode-sorting sensitivity and scalability of our approach enable on-chip parallel multiplexing over a bandwidth of 150 nanometers in the visible wavelength range. The results offer the possibility of ultrahigh-capacity and miniaturized nanophotonic devices harnessing angular momentum division.

  13. Transfer of orbital angular momentum through sub-wavelength waveguides.

    Science.gov (United States)

    Wang, Yanqin; Ma, Xiaoliang; Pu, Mingbo; Li, Xiong; Huang, Cheng; Pan, Wenbo; Zhao, Bo; Cui, Jianhua; Luo, Xiangang

    2015-02-01

    Data capacity of optical communication is achieving its limit owing to the non-linear effect of optical fiber. As an effective alternative, light carrying orbital angular momentum can greatly increase the capacity for its unprecedented degree of freedom. We demonstrate the propagation of orbital angular momentum with topological charge of 1 and 2 in plasmonic circular waveguide with sub-wavelength diameter with little propagation loss of 2.73 dB/μm, which has never been observed in optical fibers with sub-wavelength diameter. We also confirm that lights carrying orbital angular momentum can be maintained in sharp bended sub-wavelength waveguide. This plasmonic waveguide may serve as a key component in on-chip systems involving OAM.

  14. Angular trapping of anisometric nano-objects in a fluid.

    Science.gov (United States)

    Celebrano, Michele; Rosman, Christina; Sönnichsen, Carsten; Krishnan, Madhavi

    2012-11-14

    We demonstrate the ability to trap, levitate, and orient single anisometric nanoscale objects with high angular precision in a fluid. An electrostatic fluidic trap confines a spherical object at a spatial location defined by the minimum of the electrostatic system free energy. For an anisometric object and a potential well lacking angular symmetry, the system free energy can further strongly depend on the object's orientation in the trap. Engineering the morphology of the trap thus enables precise spatial and angular confinement of a single levitating nano-object, and the process can be massively parallelized. Since the physics of the trap depends strongly on the surface charge of the object, the method is insensitive to the object's dielectric function. Furthermore, levitation of the assembled objects renders them amenable to individual manipulation using externally applied optical, electrical, or hydrodynamic fields, raising prospects for reconfigurable chip-based nano-object assemblies. PMID:23016893

  15. Angular anisotropy of the fusion-fission and quasifission fragments

    CERN Document Server

    Nasirov, A K; Utamuratov, R K; Fazio, G; Giardina, G; Hanappe, F; Mandaglio, G; Manganaro, M; Scheid, W

    2007-01-01

    The anisotropy in the angular distribution of the fusion-fission and quasifission fragments for the $^{16}$O+$^{238}$U, $^{19}$F+$^{208}$Pb and $^{32}$S+$^{208}$Pb reactions is studied by analyzing the angular momentum distributions of the dinuclear system and compound nucleus which are formed after capture and complete fusion, respectively. The orientation angles of axial symmetry axes of colliding nuclei to the beam direction are taken into account for the calculation of the variance of the projection of the total spin onto the fission axis. It is shown that the deviation of the experimental angular anisotropy from the statistical model picture is connected with the contribution of the quasifission fragments which is dominant in the $^{32}$S+$^{208}$Pb reaction. Enhancement of anisotropy at low energies in the $^{16}$O+$^{238}$U reaction is connected with quasifission of the dinuclear system having low temperature and effective moment of inertia.

  16. A Differential Reflective Intensity Optical Fiber Angular Displacement Sensor.

    Science.gov (United States)

    Jia, Binghui; He, Lei; Yan, Guodong; Feng, Yong

    2016-01-01

    In this paper, a novel differential reflective intensity optical fiber angular displacement sensor was proposed. This sensor can directly measure the angular and axial linear displacement of a flat surface. The structure of the sensor probe is simple and its basic principle was first analyzed according to the intensity modulation mechanisms. Secondly, in order to trim the dark output voltage to zero, the photoelectric conversion circuit was developed to adjust the signals. Then, the sensor model including the photoelectric conversion circuit has been established, and the influence of design parameters on the sensor output characteristic has been simulated. Finally, the design parameters of the sensor structure were obtained based on the simulation results; and an experimental test system was built for the sensor calibration. Experimental results show that the linear angular range and the sensitivity of the sensor were 74.4 and 0.051 V/°, respectively. Its change rules confirm the operating principle of the sensor well. PMID:27649199

  17. A Differential Reflective Intensity Optical Fiber Angular Displacement Sensor

    Science.gov (United States)

    Jia, Binghui; He, Lei; Yan, Guodong; Feng, Yong

    2016-01-01

    In this paper, a novel differential reflective intensity optical fiber angular displacement sensor was proposed. This sensor can directly measure the angular and axial linear displacement of a flat surface. The structure of the sensor probe is simple and its basic principle was first analyzed according to the intensity modulation mechanisms. Secondly, in order to trim the dark output voltage to zero, the photoelectric conversion circuit was developed to adjust the signals. Then, the sensor model including the photoelectric conversion circuit has been established, and the influence of design parameters on the sensor output characteristic has been simulated. Finally, the design parameters of the sensor structure were obtained based on the simulation results; and an experimental test system was built for the sensor calibration. Experimental results show that the linear angular range and the sensitivity of the sensor were 74.4 and 0.051 V/°, respectively. Its change rules confirm the operating principle of the sensor well. PMID:27649199

  18. Spin-to-orbital angular momentum conversion in dielectric metasurfaces

    CERN Document Server

    Devlin, Robert Charles; Wintz, Daniel; Oscurato, Stefano Luigi; Zhu, Alexander Yutong; Khorasaninejad, Mohammadreza; Oh, Jaewon; Maddalena, Pasqualino; Capasso, Federico

    2016-01-01

    Spin-to-orbital-angular-momentum conversion has attracted considerable interest as a tool to create exotic light beams, leading to the emergence of novel devices that implement this function. These converters exploit the geometrical phase to create helical beams of handedness determined by the chirality of the incident light. This property is finding important applications in quantum optics thanks to the demonstration of liquid crystal spin-to-orbital angular momentum converters (SOC) known as q-plates. Here we demonstrate high-efficiency SOCs in the visible based on dielectric metasurfaces that generate vortex beams with high and even fractional topological charge and show for the first time the simultaneous generation of collinear helical beams with different and arbitrary orbital angular momentum. We foresee that this versatile method of creating vortex beams, which circumvents the limitations of q-plates, will significant impact microscopy and vector beam shaping.

  19. Local spacetime curvature effects on quantum orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dinesh; Mobed, Nader, E-mail: dinesh.singh@uregina.ca, E-mail: nader.mobed@uregina.ca [Department of Physics, University of Regina, Regina, Saskatchewan S4S 0A2 (Canada)

    2011-05-21

    This paper claims that local spacetime curvature can nontrivially contribute to the properties of orbital angular momentum in quantum mechanics. Of key importance is the demonstration that an extended orbital angular momentum operator due to gravitation can identify the existence of orbital states with half-integer projection quantum numbers m along the axis of quantization, while still preserving integer-valued orbital quantum numbers l for a simply connected topology. The consequences of this possibility are explored in depth, noting that the half-integer m states vanish as required when the locally curved spacetime reduces to a flat spacetime, fully recovering all established properties of orbital angular momentum in this limit. In particular, it is shown that a minimum orbital number of l = 2 is necessary for the gravitational interaction to appear within this context, in perfect correspondence with the spin-2 nature of linearized general relativity.

  20. Orbital angular momentum exchange in cylindrical-lens mode converters

    Energy Technology Data Exchange (ETDEWEB)

    Padgett, M J; Allen, L [Department of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2002-04-01

    Cylindrical-lens mode converters (Beijersbergen M W, Allen L, van der Veen H E L O and Woerdman J P 1993 Opt. Commun. 96 123-32) are used to transform between Hermite-Gaussian and Laguerre-Gaussian modes with a resulting transfer of angular momentum to the light beam and a corresponding torque on the lenses. By numerically analysing both the total and local angular momentum of the light beam, we explain the origin of this torque and confirm that is not evenly distributed between the lenses. We also confirm that any vortex contained within the beam may change sign even when the orbital angular momentum of the beam remains constant.

  1. Angular distributions for two-photon double ionization of lithium

    Science.gov (United States)

    Armstrong, G. S. J.; Colgan, J.

    2012-08-01

    We present angular distributions for two-photon double ionization of lithium at photon energies of 50 eV (λ = 25 nm) and 59 eV (λ = 21 nm). The results are obtained from full-dimensional solution of the two-active-electron time-dependent Schrödinger equation using the time-dependent close-coupling method. We investigate two different double ionization mechanisms. First, we consider direct double ionization of the Li ground state following the absorption of two photons. Secondly, we consider an initial photoexcitation of the 1s2s2p doubly excited state, followed by photoionization of the 2s and 2p electrons. We find significant differences between the angular distributions obtained for these two distinct processes. We also compare the characteristics of the angular distributions for Li with those of other two-electron atoms.

  2. Photonic polarization gears for ultra-sensitive angular measurements

    CERN Document Server

    D'Ambrosio, V; Del Re, L; Slussarenko, S; Li, Y; Kwek, L C; Marrucci, L; Walborn, S P; Aolita, L; Sciarrino, F

    2013-01-01

    A key aim in metrology is to find new physical methods for enhancing measurement precision. In this respect, quantum metrology bears great promise, but is unlikely to become practical in the near future. Its ideas can nevertheless provide inspiration for classical methods of immediate value. Here, we demonstrate the generation of NOON-like photonic states of m quanta of angular momentum, with m as high as 100, in a setup that acts as a photonic gear, converting a mechanical rotation of angle {\\theta} into an amplified rotation of the optical polarization by the angle m{\\theta}. Exploiting this effect, we demonstrate angular measurements with a precision comparable to that of the optimal quantum strategy with m photons, but robust to photon losses. The high gear ratio m translates into a similar sensitivity enhancement of optical non-contact angular measurements, boosting the current state-of-the-art by almost two orders of magnitude.

  3. Angular momentum in molecular quantum mechanical integral evaluation

    Science.gov (United States)

    Dunlap, Brett I.

    2005-01-01

    Solid-harmonic derivatives of quantum-mechanical integrals over Gaussian transforms of scalar, or radial, atomic basis functions create angular momentum about each center. Generalized Gaunt coefficients limit the amount of cross differentiation for multi-center integrals to ensure that cross differentiation does not affect the total angular momentum. The generalized Gaunt coefficients satisfy a number of other selection rules, which are exploited in a new computer code for computing forces in analytic density-functional theory based on robust and variational fitting of the Kohn-Sham potential. Two-center exponents are defined for four or more solid-harmonic differentiations of matrix elements. Those differentiations can either build up angular momentum about the centers or give forces on molecular potential-energy surfaces, thus generalized Gaunt coefficients of order greater than the number of centers are considered. These 4- j generalized Gaunt coefficients and two-center exponents are used to compute the first derivatives of all integrals involving all the Gaussian exponents on a triplet of centers at once. First all angular factors are contracted with the corresponding part of the linear-combination-of-atomic-orbitals density matrix. This intermediate quantity is then reused for the nuclear attraction integral and the integrals corresponding to each basis function in the analytic fit of the Kohn-Sham potential in the muffin-tin-like, but analytic, Slater-Roothaan method that allows molecules to dissociate into atoms having any desired energy, including the experimental electronic energy. The energy is stationary in all respects and all forces precisely agree with a previous code in tests on small molecules. During geometry optimization of an icosahedral C 720 fullerene computing these angular factors and transforming them via the 4- j generalized Gaunt coefficient takes more than sixty percent of the total computer time. These same angular factors could be used

  4. AngularJS yksisivuisen web-applikaation kehitysalustana

    OpenAIRE

    Karhu, Tuomo

    2015-01-01

    Yksisivuiset web-applikaatiot (SPA-sovellukset) ovat yleistyneet viimeisten kymmenen vuoden aikana, ja näiden avulla on ollut mahdollista tuoda verkkosivuston käyttökokemus lähemmäksi aitojen ohjelmasovellusten vastaavaa. Yksisivuisten web-applikaatioitten kehitystyöhön tarkoitetuista sovelluskehyksistä AngularJS on yksi käytetyimmistä ja suosituimmista. Työn tavoitteena on selvittää miten AngularJS-sovelluskehys soveltuu SPA-sivustojen kehitykseen sovelluskehittäjän näkökulmasta, sekä mi...

  5. On the angular momentum evolution of merged white dwarfs

    OpenAIRE

    Gourgouliatos, KN

    2006-01-01

    We study the angular momentum evolution of binaries containing two white dwarfs (WDs) which merge and become cool helium-rich supergiants. Our object is to compare predicted rotation velocities with observations of highly evolved stars believed to have formed from such a merger, which include the R CrB and extreme He stars. The principal case study involves a short-period binary containing a 0.6-M⊙ carbon–oxygen (CO) WD, and a 0.3-M⊙ He WD. The initial condition for the angular momentum distr...

  6. Molecular chirality and the orbital angular momentum of light

    CERN Document Server

    Andrews, D L; Babiker, M; Andrews, David L.; Romero, Luciana C. Davila; Babiker, Mohamed

    2003-01-01

    Optical beams with a new and distinctive type of helicity have become the subject of much recent interest. While circularly polarised light comprises photons with spin angular momentum, these optically engineered 'twisted beams' (optical vortices) are endowed with orbital angular momentum. Here, the wave- front surface of the electromagnetic fields assumes helical form. To date, optical vortices have generally been studied only in their interactions with achiral matter. This study assesses what new features, if any, can be expected when such beams are used to interrogate a chiral system.

  7. The angular momentum of condensations within elephant trunks

    CERN Document Server

    Lora, V; Esquivel, A

    2009-01-01

    The radiation from newly born stars photoevaporates their parental neutral cloud, leading to the formation of dense clumps that will eventually form stars. We present 3D simulations of the interaction of a neutral cloud with an external ionising radiation field, and compute the angular momenta of these collapsing clumps. The angular momenta of these collapsing clumps show that they have preferential orient mostly perpendicular to the direction of the incident ionising photon field. Therefore, the axes of the jet systems that will be eventually ejected (from the star + accretion disk systems that will form) will be oriented approximately perpendicular to the direction to the photoionising source.

  8. Effect of Orbital Angular Momentum on Nondiffracting Ultrashort Optical Pulses.

    Science.gov (United States)

    Ornigotti, Marco; Conti, Claudio; Szameit, Alexander

    2015-09-01

    We introduce a new class of nondiffracting optical pulses possessing orbital angular momentum. By generalizing the X-wave solution of the Maxwell equation, we discover the coupling between angular momentum and the temporal degrees of freedom of ultrashort pulses. The spatial twist of propagation invariant light pulse turns out to be directly related to the number of optical cycles. Our results may trigger the development of novel multilevel classical and quantum transmission channels free of dispersion and diffraction. They may also find application in the manipulation of nanostructured objects by ultrashort pulses and for novel approaches to the spatiotemporal measurements in ultrafast photonics.

  9. Alignment of angular velocity sensors for a vestibular prosthesis

    Directory of Open Access Journals (Sweden)

    DiGiovanna Jack

    2012-02-01

    Full Text Available Abstract Vestibular prosthetics transmit angular velocities to the nervous system via electrical stimulation. Head-fixed gyroscopes measure angular motion, but the gyroscope coordinate system will not be coincident with the sensory organs the prosthetic replaces. Here we show a simple calibration method to align gyroscope measurements with the anatomical coordinate system. We benchmarked the method with simulated movements and obtain proof-of-concept with one healthy subject. The method was robust to misalignment, required little data, and minimal processing.

  10. Energy and angular momentum of dilaton black holes

    Directory of Open Access Journals (Sweden)

    Marcelo Samuel Berman

    2008-01-01

    Full Text Available Dando seguimiento a un art culo previo, revisamos los resultados para la energ a y momento angular de un hoyo negro de Kerr-Newman, y extendemos el c alculo para el caso de un dilaton en rotaci on, obtenido a partir del modelo de Gar nkle et al. (1991, 1992. Mostramos que hay, en lo que se re ere solamente a la energ a y momento angular, una interacci on entre los campos, de forma que, el gravitacional y el electromagn etico pueden ser ocultados por la intensidad del campo escalar.

  11. Relaxation of the Angular Velocity of Pulsars after Glitches

    Science.gov (United States)

    Sedrakian, D. M.; Hayrapetyan, M. V.; Baghdasaryan, D.

    2014-03-01

    The rotational dynamics of superfluid neutron stars is examined in order to study the relaxation of the angular velocity of pulsars after glitches. The motion of the neutron-proton vortex system is investigated taking the sphericity of the superfluid core and vortex pinning and depinning into account. A relaxation solution is obtained for the angular rotation velocity of pulsars after glitches. In order to compare this solution with observational data for the Vela pulsar, the inverse problem of finding the initial distribution of vortices immediately after a glitch is solved.

  12. Angular velocity response of nanoparticles dispersed in liquid crystal

    Science.gov (United States)

    Huang, Pin-Chun; Shih, Wen-Pin

    2013-06-01

    A hybrid material of nanoparticles dispersed in liquid crystal changed capacitance after spinning beyond threshold angular velocity. Once the centrifugal force of nanoparticles overcomes the attractive force between liquid crystals, the nanoparticles begin to move. The order of highly viscous liquid crystals is disturbed by the nanoparticles' penetrative movement, and the dielectric constant of the liquid crystal cell changes as a result. We found that the angular velocity response of nanoparticles dispersed in liquid crystal with higher working temperature and nanoparticles' density provided higher sensitivity. The obtained results are important for the continuous improvement of liquid-crystal-based inertial sensors or nano-viscometers.

  13. Quark Spin and Orbital Angular Momentum in the Baryon

    OpenAIRE

    Song, X.

    1999-01-01

    The spin and orbital angular momentum carried by different quark flavors in the nucleon are calculated in the SU(3) chiral quark model with symmetry-breaking. The model is extended to all octet and decuplet baryons. In this model, the reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as function of the partition factor $\\kappa...

  14. Radius of a Photon Beam with Orbital Angular Momentum

    OpenAIRE

    Davis, Basil L.; Kaplan, L.

    2012-01-01

    We analyze the transverse structure of the Gouy phase shift in light beams carrying orbital angular momentum and show that the Gouy radius $r_G$ characterizing the transverse structure grows as $\\sqrt{2p+|\\ell|+1}$ with the nodal number $p$ and photon angular momentum number $\\ell$. The Gouy radius is shown to be closely related to the root-mean-square radius of the beam, and the divergence of the radius away from the focal plane is determined. Finally, we analyze the rotation of the Poynting...

  15. Kinetic description of electron plasma waves with orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, J. T. [IPFN, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2012-11-15

    We describe the kinetic theory of electron plasma waves with orbital angular momentum or twisted plasmons. The conditions for a twisted Landau resonance to exist are established, and this concept is introduced for the first time. Expressions for the kinetic dispersion relation and for the electron Landau damping are derived. The particular case of a Maxwellian plasma is examined in detail. The new contributions to wave dispersion and damping due the orbital angular momentum are discussed. It is shown that twisted plasmons can be excited by rotating electron beams.

  16. Undulator radiation carrying spin and orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Shigemi [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)], E-mail: sasaki@aps.anl.gov; McNulty, Ian; Dejus, Roger [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2007-11-11

    We show that the radiation from a helical undulator not only carries spin angular momentum (circular polarization) but also orbital angular momentum. This exotic property of the undulator radiation may be useful in coherent X-ray imaging and scattering experiments and to probe electronic transitions in matter by orbital dichroism spectroscopy. Also, we present that a new magnet configuration, similar to the structure of Figure-8 undulator or the PERA undulator, may generate right- and left-hand circularly polarized off-axis radiation simultaneously.

  17. Orbital angular momentum and generalized transverse momentum distribution

    Science.gov (United States)

    Zhao, Yong; Liu, Keh-Fei; Yang, Yi-Bo

    2016-03-01

    We show that, when boosted to the infinite momentum frame, the quark and gluon orbital angular momentum operators defined in the nucleon spin sum rule of Chen et al. are the same as those whose matrix elements correspond to the moments of generalized transverse momentum distributions. This completes the connection between the infinite momentum limit of each term in that sum rule and experimentally measurable observables. We also show that these orbital angular momentum operators can be defined locally and discuss the strategies of calculating them in lattice QCD.

  18. Undulator radiation carrying spin and orbital angular momentum.

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S.; McNulty, I.; Dejus, R.; X-Ray Science Division

    2007-11-11

    We show that the radiation from a helical undulator not only carries spin angular momentum (circular polarization) but also orbital angular momentum. This exotic property of the undulator radiation may be useful in coherent X-ray imaging and scattering experiments and to probe electronic transitions in matter by orbital dichroism spectroscopy. Also, we present that a new magnet configuration, similar to the structure of Figure-8 undulator or the PERA undulator, may generate right- and left-hand circularly polarized off-axis radiation simultaneously.

  19. Scalable broadband OPCPA in Lithium Niobate with signal angular dispersion

    Science.gov (United States)

    Tóth, György; Pálfalvi, László; Tokodi, Levente; Hebling, János; Fülöp, József András

    2016-07-01

    Angular dispersion of the signal beam is proposed for efficient, scalable high-power few-cycle pulse generation in LiNbO3 by optical parametric chirped-pulse amplification (OPCPA) in the 1.4 to 2.1 μm wavelength range. An optimized double-grating setup can provide the required angular dispersion. Calculations predict 16.8 fs (3 cycles) pulses with 13 TW peak power. Further scalability of the scheme towards the 100-TW power level is feasible by using efficient, cost-effective, compact diode-pumped solid-state lasers for pumping directly at 1 μm, without second-harmonic generation.

  20. Efficient Sorting of Free Electron Orbital Angular Momentum

    CERN Document Server

    McMorran, Benjamin J; Lavery, Martin P J

    2016-01-01

    We propose a method for sorting electrons by orbital angular momentum (OAM). Several methods now exist to prepare electron wavefunctions in OAM states, but no technique has been developed for efficient, parallel measurement of pure and mixed electron OAM states. The proposed technique draws inspiration from the recent demonstration of the sorting of OAM through modal transformation. We show that the same transformation can be performed with electrostatic electron optical elements. Specifically, we show that a charged needle and an array of electrodes perform the transformation and phase correction necessary to sort orbital angular momentum states. This device may enable the analysis of the spatial mode distribution of inelastically scattered electrons.

  1. Angular dependence of anisotropic magnetoresistance in magnetic systems

    Science.gov (United States)

    Zhang, Steven S.-L.; Zhang, Shufeng

    2014-05-01

    Anisotropic magnetoresistance (AMR), whose physical origin is attributed to the combination of spin dependent scattering and spin orbital coupling (SOC), usually displays simple angular dependence for polycrystalline ferromagnetic metals. By including generic spin dependent scattering and spin Hall (SH) terms in the Ohm's law, we explicitly show that various magneto-transport phenomena such as anomalous Hall (AH), SH, planar Hall (PH) and AMR could be quantitatively related for bulk polycrystalline ferromagnetic metals. We also discuss how AMR angular dependence is affected by the presence of interfacial SOC in magnetic layered structure.

  2. The evolution of black-hole mass and angular momentum

    CERN Document Server

    King, A R

    1999-01-01

    We show that neither accretion nor angular momentum extraction are likely to lead to significant changes in the mass M_1 or angular momentum parameter a_* of a black hole in a binary system with realistic parameters. Current values of M_1 and a_* therefore probably reflect those at formation. We show further that sufficiently energetic jet ejection powered by the black hole's rotational energy can stabilize mass transfer in systems with large adverse mass ratios, and even reduce the mass transfer rate to the point where the binary becomes transient.

  3. Ligand inducible assembly of a DNA tetrahedron.

    Science.gov (United States)

    Dohno, Chikara; Atsumi, Hiroshi; Nakatani, Kazuhiko

    2011-03-28

    Here we show that a small synthetic ligand can be used as a key building component for DNA nanofabrication. Using naphthyridinecarbamate dimer (NCD) as a molecular glue for DNA hybridization, we demonstrate NCD-triggered formation of a DNA tetrahedron.

  4. Chemistry of Marine Ligands and Siderophores

    OpenAIRE

    Vraspir, Julia M.; Butler, Alison

    2009-01-01

    Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cad...

  5. Fas ligand deficiency in HIV disease

    OpenAIRE

    Sieg, Scott; Smith, Dawn; Yildirim, Zafer; Kaplan, David

    1997-01-01

    Apoptosis is postulated to be involved as an anti-viral immune mechanism by killing infected cells before viral replication has occurred. The Fas–Fas ligand interaction is a powerful regulator of T cell apoptosis and could potentially act as a potent anti-viral immune mechanism against T cell tropic virus such as human immunodeficiency virus (HIV). We investigated the status of Fas ligand in peripheral blood mononuclear cells (PBMCs) obtained from persons infected with HIV. We found that mono...

  6. Lanthanide complexes derived from hexadentate macrocyclic ligand: Synthesis, spectroscopic and thermal investigation

    Science.gov (United States)

    Chandra, Sulekh; Tyagi, Monika; Rani, Soni; Kumar, Sumit

    2010-02-01

    The lanthanide complexes derived from (3,5,13,15-tetramethyl 2,6,12,16,21-22-hexaazatricyclo[15.3.I 1-17I 7-11]cosa-1(21),2,5,7,9,11(22),12,15,17,19-decane) were synthesized. The complexes were found to have general composition [Ln(L)X 2·H 2O]X, where Ln = La 3+, Ce 3+, Nd 3+, Sm 3+ and Eu 3+ and X = NO 3- and Cl -. The ligand was characterized by elemental analyses, IR, Mass, and 1H NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, Mass, electronic spectral techniques and thermal studies. The ligand acts as a hexadentate and coordinates through four nitrogen atoms of azomethine groups and two nitrogen of pyridine ring. The lanthanum complexes are diamagnetic while the other Ln(III) complexes are paramagnetic. The spectral parameters i.e. nephelauxetic ratio ( β), covalency factor ( b1/2), Sinha parameter ( δ%) and covalency angular overlap parameter ( η) have been calculated from absorption spectra of Nd(III) and Sm(III) complexes. These parameters suggest the metal-ligand covalent bonding. In the present study, the complexes were found to have coordination number nine.

  7. Designer TGFβ superfamily ligands with diversified functionality.

    Directory of Open Access Journals (Sweden)

    George P Allendorph

    Full Text Available Transforming Growth Factor--beta (TGFβ superfamily ligands, including Activins, Growth and Differentiation Factors (GDFs, and Bone Morphogenetic Proteins (BMPs, are excellent targets for protein-based therapeutics because of their pervasiveness in numerous developmental and cellular processes. We developed a strategy termed RASCH (Random Assembly of Segmental Chimera and Heteromer, to engineer chemically-refoldable TGFβ superfamily ligands with unique signaling properties. One of these engineered ligands, AB208, created from Activin-βA and BMP-2 sequences, exhibits the refolding characteristics of BMP-2 while possessing Activin-like signaling attributes. Further, we find several additional ligands, AB204, AB211, and AB215, which initiate the intracellular Smad1-mediated signaling pathways more strongly than BMP-2 but show no sensitivity to the natural BMP antagonist Noggin unlike natural BMP-2. In another design, incorporation of a short N-terminal segment from BMP-2 was sufficient to enable chemical refolding of BMP-9, without which was never produced nor refolded. Our studies show that the RASCH strategy enables us to expand the functional repertoire of TGFβ superfamily ligands through development of novel chimeric TGFβ ligands with diverse biological and clinical values.

  8. Construction of dinuclear complexes using multidentate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Sampson, C.L

    2000-04-01

    This work details the synthesis of novel copper(I), copper(II), nickel(II) and zinc(II) dinuclear complexes. Attempts have been made to control the co-ordination architectures of the metal centres by using bis-bidentate and tridentate chelating N,S- and N-donor ligands to generate dinuclear systems. The ligands were both symmetrically and asymmetrically disubstituted pyridazine-based and pyridine-based ligands consisting of a mixture of N-only and mixed N,S-donors. The study using the pyridazine-based ligands continues previous research in our group using 3,6-bis disubstituted pyridazine-based ligands to form complexes with copper(l) and copper(II). The pyridazine-based ligands have been seen to be bis-bidentate upon co-ordination of copper. The pyridazine-based ligands could be envisaged to generate dinuclear complexes by directly bridging between two metal ions. This study involved the formation of copper(l), nickel(II) and zinc(II) complexes with these ligands. The structural properties of two particular complexes have been explored using X-ray crystallography and spectroscopic techniques. Pyridine-based ligands have also been used previously in our group as tridentate chelating ligands. They have been seen to form dinuclear complexes with copper(I) and copper(II) when reacted with an additional bridging ligand e.g. 4,4'-bipyridine. This provides an alternative method for generating dinuclear complexes. Chapter 1 presents an introduction to the area of supramolecular chemistry from which we can learn the principles of polymer formation and them 'in reverse' to generate discrete dinuclear systems. Chapter 2 details the synthesis of the pyridazine and pyridine-based ligands including a detailed nmr study of the ligands. Since the ligands were synthesised using cyclic thioamides as terminal groups it has been found that thiol-thione tautomerisation occurred during synthesis giving rise to two possible ligand conformations. The nmr study has been used

  9. LigandRFs: random forest ensemble to identify ligand-binding residues from sequence information alone

    KAUST Repository

    Chen, Peng

    2014-12-03

    Background Protein-ligand binding is important for some proteins to perform their functions. Protein-ligand binding sites are the residues of proteins that physically bind to ligands. Despite of the recent advances in computational prediction for protein-ligand binding sites, the state-of-the-art methods search for similar, known structures of the query and predict the binding sites based on the solved structures. However, such structural information is not commonly available. Results In this paper, we propose a sequence-based approach to identify protein-ligand binding residues. We propose a combination technique to reduce the effects of different sliding residue windows in the process of encoding input feature vectors. Moreover, due to the highly imbalanced samples between the ligand-binding sites and non ligand-binding sites, we construct several balanced data sets, for each of which a random forest (RF)-based classifier is trained. The ensemble of these RF classifiers forms a sequence-based protein-ligand binding site predictor. Conclusions Experimental results on CASP9 and CASP8 data sets demonstrate that our method compares favorably with the state-of-the-art protein-ligand binding site prediction methods.

  10. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H2O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ωQ = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H2O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ωQ = 168 Mrad/s. (orig.)

  11. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Cecilia Y. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivas, Patricia [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Universidad Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Pasquevich, Alberto F. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)

    2014-07-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H{sub 2}O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω{sub Q} = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H{sub 2}O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω{sub Q} = 168 Mrad/s. (orig.)

  12. Synthesis and characterization of mixed ligand chiral nanoclusters

    KAUST Repository

    Guven, Zekiye P.

    2016-06-22

    Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. While the chiral ligand led mostly to the formation of nanoparticles, the presence of the achiral ligand drastically increased the yield of nanoclusters with enhanced chiral properties. © 2016 The Royal Society of Chemistry.

  13. AngularJS : yksisivuisen web-sovelluksen käyttöliittymän toteutus AngularJS:llä

    OpenAIRE

    Suomijoki, Juha

    2015-01-01

    Opinnäytetyössä tutkittiin mikä on AngularJS-JavaScript-ohjelmistokehys ja miten se soveltuu yksisivuisen web-sovelluksen käyttöliittymän toteutukseen. AngularJS on vuonna 2012 julkaistu Googlen ylläpitämä JavaScript-ohjelmistokehys, joka on tarkoitettu ensisijaisesti yksisivuisten web-sovellusten kehittämiseen. Opinnäytetyön teoriaosuudessa tutkittiin mikä AngularJS on ja mitkä ovat AngularJS:n keskeiset konseptit ja sovelluskomponentit. Tarkastelu pohjautui AngularJS:stä kirjoitettu...

  14. Angular correlation of annihilation photons in ice single crystals

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Kvajic, G.; Eldrup, Morten Mostgaard;

    1971-01-01

    Linear-slit angular-correlation curves were obtained at - 148 °C for the [0001], [10¯10], and [11¯20] directions in single crystals of ice. Besides the narrow central peak, pronounced narrow side peaks were also observed. They occurred at angles θ=2πℏgz/mc, where gz is the projection of reciprocal...

  15. Large angular momentum closed strings colliding with D-branes

    OpenAIRE

    Imamura, Yosuke

    2002-01-01

    We investigate colliding processes of closed strings with large angular momenta with D-branes. We give explicit CFT calculations for closed string states with an arbitrary number of bosonic excitations and no or one fermion excitation. The results reproduce the correspondence between closed string states and single trace operators in the boundary gauge theory recently suggested by Berenstein, Maldacena and Nastase.

  16. Energy and linear and angular momenta in simple electromagnetic systems

    CERN Document Server

    Mansuripur, Masud

    2015-01-01

    We present examples of simple electromagnetic systems in which energy, linear momentum, and angular momentum exhibit interesting behavior. The systems are sufficiently simple to allow exact solutions of Maxwell's equations in conjunction with the electrodynamic laws of force, torque, energy, and momentum. In all the cases examined, conservation of energy and momentum is confirmed.

  17. The parton orbital angular momentum: Status and prospects

    Science.gov (United States)

    Liu, Keh-Fei; Lorcé, Cédric

    2016-06-01

    Theoretical progress on the formulation and classification of the quark and gluon orbital angular momenta (OAM) is reviewed. Their relation to parton distributions and open questions and puzzles are discussed. We give a status report on the lattice calculation of the parton kinetic and canonical OAM and point out several strategies to calculate the quark and gluon canonical OAM on the lattice.

  18. QCD in the infrared with exact angular integrations

    NARCIS (Netherlands)

    Atkinson, D; Bloch, J.C R

    1998-01-01

    In a previous paper we have shown that in quantum chromodynamics the gluon propagator vanishes in the infrared limit, while the ghost propagator is more singular than a simple pole. These results were obtained after angular averaging, but here we go beyond this approximation and perform an exact cal

  19. Estimating Discrete Power Angular Spectra in Multiprobe OTA Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2014-01-01

    The letter discusses over-the-air (OTA) testing for multiple-input–multiple-output (MIMO) capable terminals with emphasis on estimating discrete power angular spectrum modeled at the receiver (Rx) side in the test zone. Two techniques based on a uniform circular array (UCA) are proposed to obtain...

  20. A new uncertainty relation for angular momentum and angle

    International Nuclear Information System (INIS)

    An uncertainty relation of the form ΔL2ΔSo >=sup(h/2π)/sub(2) is derived for angular momentum and angle. The non-linear operator So measures angles and has a simple interpretation. Subject to very general conditions of rotational invariance the above relation is unique. Radial momentum is not quantized