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1

Sonochemical synthesis and characterization of new one-dimensional manganese(II) coordination polymer nanostructures.  

PubMed

A new Mn(II) coordination polymer, [Mn (L1)2(NCS)2]n (1) [L1=3,4-bis(4-pyridyl)-5-(2-pyridyl)-1,2,4-triazole] was synthesized by the reaction of ligand L1 and mixtures of manganese(II) acetate and potassium thiocyanate using the heat gradient method. Compound 1 has been characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The crystal structure of compound 1 was determined by single-crystal X-ray diffraction and shows a new interesting one-dimensional coordination polymer. Nanostructures of compound 1 have been synthesized by sonochemical method. The products were characterized by X-ray powder diffraction, scanning electron microscopy (SEM), and IR spectroscopy. The thermal stability of nano particles of compound 1 was studied by thermal gravimetric and differential thermal analyses. PMID:25483353

Morsali, Ahmad; Hosseini-Monfared, Hassan; Morsali, Ali; Mayer, Peter

2015-05-01

2

One-dimensional Coordination Polymer as New Precursor for Preparation of Fe 2 O 3 Nanoparticles  

Microsoft Academic Search

A Fe(II) one-dimensional coordination polymer, [Fe(pyterpy)2](SCN)2.MeOH (1), which pyterpy is 4?-(4-Pyridyl)-2,2?:6?,2?-terpyridine, has been synthesized by using branched tube and characterized by\\u000a elemental analysis, X-ray powder diffraction (XRD) and IR spectroscopy. Iron(III) oxide nano-particles were obtained by thermolysis\\u000a of compound 1 in oleic acid (surfactant) at 286 °C under air atmosphere. The Fe2O3 nano-particles were characterized by XRD and scanning electron microscopy.

Azadeh MehraniAli Morsali; Ali Morsali

3

Self-assembly as a route to one-dimensional lanthanum(III) salicylaldimine coordination polymer  

Microsoft Academic Search

The self-assembled formation of a one-dimensional lanthanum salicylaldimine coordination polymer was proved by the X-ray diffraction analysis of new lanthanum(III) nitrate complex containing N,N'-bis(salicylidene)-1,5-pentanediamine ligand (H2L). It was obtained in situ in a one-step, metal-templated condensation of salicylaldehyde with 1,5-pentanediamine (cadaverine, biogenic polyamine) and characterized by microanalysis and spectroscopic (IR, ESI-MS, UV-Vis, and 1H NMR) data. The [La(NO3)3(?-H2L)2]? complex displayed

Wanda Radecka-Paryzek; Izabela Pospieszna-Markiewicz; Maciej Kubicki

2010-01-01

4

Magnetic study of a one-dimensional Mn(II) coordination polymer dealing with ?-? stacking  

NASA Astrophysics Data System (ADS)

A new one-dimensional chain manganese(II) coordination polymer, {[Mn(?-Dpd)(Q) 2(H 2O) 2]2(ClO 4)} n (Dpd = 2,5-dimethylpyrazine-1,4-dioxide; Q = 8-hydroxylquinoline N-oxide), was synthesized with 2,5-dimethylpyrazine-1,4-dioxide as bridge ligand and 8-hydroxylquinoline N-oxide as terminal ligand, and its crystal structure determined by X-ray crystallography. The structure analysis indicates that there are two pathways for magnetic interactions: one is through bridge ligand 2,5-dimethylpyrazine-1,4-dioxide, and another is by ?-? stacking of adjacent quinoline rings. The theoretical calculations reveal that there exist a anti-ferromagnetic interaction from spin delocalization and a ferromagnetic interaction from spin polarization for 2,5-dimethylpyrazine-1,4-dioxide bridge pathway, but the anti-ferromagnetic interaction is stronger than the ferromagnetic interaction, leading to an anti-ferromagnetic interaction with J = -2.53 cm -1; whereas for the ?-? stacking pathway it resulted in a ferromagnetic interaction with J = 0.013 cm -1. The experimental fitting on the data of the variable temperature magnetic susceptibilities gave the magnetic interaction constant J = 0.07 cm -1, which is similar with the results of the theoretical calculations.

Shi, Jing-Min; Meng, Xian-Zhe; Sun, You-Min; Xu, Hai-Yan; Shi, Wei; Cheng, Peng; Liu, Lian-Dong

2009-01-01

5

One-dimensional (1D) europium coordination polymer wires: Synthesis, characterization and photoluminescence properties  

Microsoft Academic Search

1D europium coordination polymer wires were successfully prepared by reacting europium chloride with tributyl phosphate (TBP) at 160 °C for 12 h. The products were characterized by XRD, IR, TG, DTA, SEM, and EDS. SEM results showed that the wires were with diameters ranging from several hundreds of nanometers to ?5 ?m and lengths going up to several hundreds of

Longfei LUO; Rong XU; Dong ZHAO; Shengliang ZHONG

2010-01-01

6

A novel one-dimensional mixed ligands silver(I) coordination polymer containing two different chains  

NASA Astrophysics Data System (ADS)

A mixed-ligand coordination polymer (CP) of the formula {[Ag3(bmimb)2 (ndca)1.5]·H2O}n (1) (where bmimb = 1,4-bis(2-methylimidazol-1-ylmethyl)benzene and H2ndca = naphthalene-1,4-dicarboxylic acid) was synthesized by reaction of Ag2O and bmimb ligand with H2ndca under the ammoniacal condition. It has been structurally characterized by element analysis, IR and X-ray single-crystal diffraction. The bmimb acts as bidentate ?2-N,N' ligand, and the ndca ligand adopts two different coordination modes in 1, which are ?4-?1:?1:?1:?1 and ?2-?1:?0:?1:?0, respectively. Coordination of Ag(I) ions with bmimb and ndca ligands produces two different 1D chains, which is attributed to the different coordination modes of the ndca ligand, indicating the ndca ligand plays an important role in the formation of the diverse 1D chains. The complex 1 exhibits photoluminescent emission in the solid state at room temperature.

Liu, Fu-Jing; Sun, Di; Hao, Hong-Jun; Huang, Rong-Bin; Zheng, Lan-Sun

2012-04-01

7

A one-dimensional zinc(II) coordination polymer based on mixed multidentate N- and O-donor ligands.  

PubMed

In the title coordination polymer, catena-poly[[bis[{1-[(1H-benzimidazol-2-yl-?N(3))methyl]-1H-tetrazole}zinc(II)]-bis(?4-pentane-1,5-dioato-1:2:1':2'?(4)O(1):O(1'):O(5):O(5'))] methanol disolvate], {[Zn(C5H6O4)(C9H8N6)]·CH3OH}n, each Zn(II) ion is five-coordinated by four O atoms from four glutarate ligands and by one N atom from a 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) ligand, leading to a slightly distorted square-pyramidal coordination environment. Two Zn(II) ions are linked by four bridging glutarate carboxylate groups to generate a dinuclear [Zn2(CO2)4] paddle-wheel unit. The dinuclear units are further connected into a one-dimensional chain via the glutarate ligands. The bimt ligands coordinate to the Zn(II) ions in a monodentate mode and are pendant on both sides of the main chain. In the crystal, the chains are linked by O-H...O and N-H...O hydrogen bonds into a two-dimensional layered structure. Adjacent layers are further packed into a three-dimensional network through van der Waals forces. A thermogravimetric analysis was carried out and the photoluminescent behaviour of the polymer was investigated. PMID:25836291

Huang, Qiu Ying; Zhang, Yu Hong; Meng, Xiang Ru

2015-04-01

8

One-dimensional lanthanide coordination polymers: synthesis, structures, and single-ion magnetic behaviour.  

PubMed

A family of isostructural one-dimensional (1D) lanthanide compounds with the formula [Ln(III)(L)(NO3)(DMF)2]?, where Ln = Tb (), Dy (), Ho () and Er (), was synthesised and structurally characterised. The magnetic behaviour of these compounds is demonstrated, and their static and dynamic properties are discussed and analyzed. The results of dc magnetic susceptibility measurements regarding compounds indicate the existence of thermal depopulation of the crystal field-induced splitting of mJ levels of Ln ions, while the observed frequency-dependent out-of-phase ac magnetic susceptibility signals under certain magnetic fields for compounds , , and show a slow relaxation of the magnetisation with an energy barrier of 6.15, 54.45, and 28.14 K, respectively. Also, complex shows peak maxima of ?M'' signals in temperature-dependent as well as frequency-dependent ac magnetic susceptibility measurements under an appropriate magnetic field, indicating that the relaxation process is dominantly thermally activated. PMID:25608236

Feng, Hung-Kai; Huang, Po-Jung; Tsai, Hui-Lien

2015-02-10

9

Controlling spin transition in one-dimensional coordination polymers through polymorphism.  

PubMed

A series of polymer 1 microcrystals with several different morphologies have been systematically synthesized by controlling experimental parameters, namely concentration of reactants, temperature, solvent nature, and the use of surfactants, and their valence tautomerism (VT) has been studied by combined electron microscopy, X-ray diffraction data, and magnetization. Our results indicate that all of them can be grouped exclusively into two different crystalline phases, or a mixture of them, that critically determine the VT process, independent of the morphology and/or dimensions of the crystals. Moreover, a difference in the critical temperature of both phases by more than 50 K allows us to regulate VT. These results head the use of valence tautomeric 1D polymers in devices where strict control and reproducibility of the switching behavior at different length scales and integration procedures is highly required. PMID:25100660

Novio, Fernando; Campo, Javier; Ruiz-Molina, Daniel

2014-08-18

10

Two-Dimensional Coordination Polymers with One-Dimensional Magnetic Chains: Hydrothermal Synthesis, Crystal Structure, and Magnetic and Thermal Properties of  

E-print Network

, Crystal Structure, and Magnetic and Thermal Properties of 2 [MCl2(4,4-bipyridine)] (M ) Fe, Co, Ni, CoTwo-Dimensional Coordination Polymers with One-Dimensional Magnetic Chains: Hydrothermal Synthesis.611(1) Ã?, V ) 492.57(18) Ã?3, Z ) 2. The structure is a noninterpenetrating two-dimensional network

Li, Jing

11

Ultrasonic irradiation assisted syntheses of one-dimensional di(azido)-dipyridylamine Cu(II) coordination polymer nanoparticles.  

PubMed

The Cu(II) coordination polymer, [Cu(dpa)(N?)?]n (1), has been synthesized by the reaction of 2,2'-dipyridylamine (dpa) and a mixture of Cu(ClO?)?·6H?O and sodium azide under ultrasonic irradiation. The products were characterized by infrared (FT-IR) spectroscopy, X-ray powder diffraction, and scanning electron microscopy (SEM). The CuO nano particles were prepared from calcination of compound 1 at 873 K. The CuO nanoparticles were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM). This study demonstrates that sonochemistry is a suitable method for the preparation of coordination polymer nano-structures and that the calcination temperature can be an effective parameter to control the size of CuO nano-structures prepared by direct calcination of a coordination polymer. PMID:25164270

Morsali, Ahmad; Monfared, Hassan Hosseini; Morsali, Ali; Janiak, Christoph

2015-03-01

12

One-dimensional transport in polymer nanofibers  

E-print Network

We report our transport studies in quasi one-dimensional (1D) conductors - helical polyacetylene fibers doped with iodine and the data analysis for other polymer single fibers and tubes. We found that at 30 K liquid or Wigner crystal. The relationship between our results and theories for tunneling in 1D systems is discussed.

A. N. Aleshin; H. J. Lee; Y. W. Park; K. Akagi

2004-10-08

13

Color-tunable and white-light emission of one-dimensional l-di-2-thenoyltartaric acid mixed-lanthanide coordination polymers.  

PubMed

A series of l-di-2-thenoyltartaric acid lanthanide coordination polymers, namely, {[La2L3(CH3OH)6(H2O)]·CH3OH·H2O}n (), {[Ln2L3(CH3OH)x(H2O)6-x]·aCH3OH·bH2O}n, [Ln = Eu (), x = 2, a = 0.5, b = 0.25; Ln = Gd (), x = 3, a = 1, b = 0; Ln = Tb (), x = 2, a = 1, b = 0], {[(Eu0.037Tb0.963)2L3(CH3OH)2(H2O)4]·CH3OH·2.75H2O}n (), {[(Eu0.051Tb0.406La0.543)2L3(CH3OH)2(H2O)4]·0.5CH3OH·2H2O}n (), and {[(Eu0.068Tb0.363Gd0.569)2L3(CH3OH)3(H2O)3]·CH3OH·H2O}n (), have been synthesized using facile reactions of H2L (H2L = l-di-2-thenoyltartaric acid) with LnCl3·6H2O under ambient temperature. X-ray crystallographic analysis reveals that complexes are isostructural, featuring one-dimensional (1D) ladder-like chain structures, in which the Ln(3+) ions are bridged by the carboxylate groups of the ligands. The luminescent spectra in the solid state at room temperature reveal that complexes and exhibit the characteristic red and green luminescence of Eu(3+) and Tb(3+) ions, respectively, whereas complexes and display the blue emission of the ligand with a broad band centered at 422 nm. Notably, the mixed-lanthanide coordination polymers exhibit color-tunable luminescence from yellow and white to blue upon variation of the excitation wavelength. It realizes color-tunable and white-light emission in 1D carboxylic acid mixed-lanthanide coordination polymers. PMID:25661972

Feng, Chang; Sun, Jing-Wen; Yan, Peng-Fei; Li, Yu-Xin; Liu, Tian-Qi; Sun, Qing-Yan; Li, Guang-Ming

2015-02-24

14

One-dimensional zig-zag type coordination polymers of Ni(II) and Cu(II) containing 1,3-benzenedicarboxylate and  

E-print Network

involving coordination polymers. Compared to malonic, succinic, glutaric and adipic acids which have useful candidates for applications relating to sorption, storage, host­guest, catalytic, magnetic flexible ­CH2­ spacer functions of varying lengths, benzenedicarboxylic acids have a rigid aromatic unit

Li, Jing

15

A novel one-dimensional manganese(II) coordination polymer containing both dicyanamide and pyrazinamide ligands: Synthesis, spectroscopic investigations, X-ray studies and evaluation of biological activities.  

PubMed

A novel 1D coordination polymer {[Mn(?1,5-dca)2(PZA)2](PZA)2}n, 1, has been synthesized and characterized by single crystal X-ray crystallography. The coordination mode of dicyanamide (dca) and pyrazinamide (PZA) ligands was inferred by IR spectroscopy. The compound 1 was evaluated for in vitro antimycobacterial and antitumor activities. It demonstrated better in vitro activity against Mycobacterium tuberculosis than pyrazinamide and its MIC value was determined. Complex 1 was also screened for its in vitro antitumor activity towards LM3 and LP07 murine cancer cell lines. In addition, the antibacterial activity of complex 1 has been tested against Gram(+) and Gram(-) bacteria and it has shown promising broad range anti-bacterial activity. PMID:25574649

Tabrizi, Leila; Chiniforoshan, Hossein; McArdle, Patrick

2015-03-15

16

Magnetic property and theoretical study on a new one-dimensional coordination polymer [Co(? 1,3-SCN)(?-MPyO)(SCN)(CH 3OH)] n with mixed bridging ligands  

NASA Astrophysics Data System (ADS)

A new one-dimensional coordination polymer [Co(? 1,3-SCN)(?-MPyO)(SCN)(CH 3OH)] n (where MPyO = 4-methylpyridine N-oxide) has been synthesized and its crystal structure determined by X-ray crystallography. In the complexes, there exist two kinds of bridging ligands, namely, ? 1,3-SCN - bridging ligand and ?-MPyO bridging ligand. The two kinds of bridging ligands coordinate to the Co(II) ions with alternating way and which led to the formation of the one-dimensional chain. The density function calculations have been carried out on the complex to analyze the magnetic coupling mechanism. The calculations reveal that magnetic coupling values are J = -20.32 cm -1 from MPyO bridged Co(II) ions and J = -0.87 cm -1 from ? 1,3-SCN - bridged Co(II) ions. The fitting of the susceptibility data (4-300 K) was performed by using one-dimensional Co(II) coupling formula which gave the J = -7.19 cm -1 and J' = -1.28 cm -1.

Shi, Jing-Min; Liu, Zhe; Sun, You-Min; Yi, Long; Liu, Lian-Dong

2006-06-01

17

A meso-one-dimensional coordination polymer based on racemic 2-(1-oxo-1 H-2,3-dihydroisoindol-2-yl)benzoic acid: Synthesis, structure and properties  

NASA Astrophysics Data System (ADS)

A novel polymeric complex NaCo( o-pba) 3(H 2O) 3 ( o-Hpba = 2-(1-oxo-1 H-2,3-dihydroisoindol-2-yl)benzonic acid) based on racemic N-arylphthalimidine ligand has been prepared and characterized by elemental analysis, spectroscopic and X-ray crystallography methods. In the compound, each Co(II) cation is coordinated by six O atoms from three carboxyl groups of o-pba - and three water molecules in fac-MA 3B 3 model forming a chiral tripodal Co( o-pba) 3(H 2O) 3- anion-complex, enantiomeric pairs of which are alternately arranged in head-to-head and tail-to-tail orientations giving rise to a meso-one-dimensional chain-like structure. The compound exhibits high stability and unusual triple-peak luminescence in DMSO solution at room temperature.

Li, Hui; Chen, Yun; Ying, Shao-Ming; Zhang, Jian; Liu, Hui

2009-11-01

18

Luminescent lanthanide coordination polymers  

SciTech Connect

One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

1999-12-13

19

Coordination polymers  

Microsoft Academic Search

1.The properties of the beryllium-containing internal-complex polymer derived from bis-p-acetoacetylphenyl ether were investigated.2.The polymer is stable to heat: appreciable decomposition sets in only after long heating above 280°. The rate and extent of the degradation of the polymer at high temperatures are higher in air than in nitrogen. The internal-complex polymer undergoes no substantial change in properties as a result

M. G. Vinogradov; S. V. Vinogradova; Yu. A. Davidovich; V. V. Korshak

1963-01-01

20

$N$-point free energy distribution function in one dimensional random directed polymers  

E-print Network

Explicit expression for the $N$-point free energy distribution function in one dimensional directed polymers in a random potential is derived in terms of the Bethe ansatz replica technique. The obtained result is equivalent to the one derived earlier by Prolhac and Spohn [J. Stat. Mech., 2011, P03020].

V. Dotsenko

2014-10-15

21

Distribution function of the endpoint fluctuations of one-dimensional directed polymers in a random potential  

E-print Network

The explicit expression for the the probability distribution function of the endpoint fluctuations of one-dimensional directed polymers in random potential is derived in terms of the Bethe ansatz replica technique by mapping the replicated problem to the N-particle quantum boson system with attractive interactions.

Victor Dotsenko

2013-01-22

22

Reaction coordinates, one-dimensional Smoluchowski equations, and a test for dynamical self-consistency  

NASA Astrophysics Data System (ADS)

We propose a method for identifying accurate reaction coordinates among a set of trial coordinates. The method applies to special cases where motion along the reaction coordinate follows a one-dimensional Smoluchowski equation. In these cases the reaction coordinate can predict its own short-time dynamical evolution, i.e., the dynamics projected from multiple dimensions onto the reaction coordinate depend only on the reaction coordinate itself. To test whether this property holds, we project an ensemble of short trajectory swarms onto trial coordinates and compare projections of individual swarms to projections of the ensemble of swarms. The comparison, quantified by the Kullback-Leibler divergence, is numerically performed for each isosurface of each trial coordinate. The ensemble of short dynamical trajectories is generated only once by sampling along an initial order parameter. The initial order parameter should separate the reactants and products with a free energy barrier, and distributions on isosurfaces of the initial parameter should be unimodal. The method is illustrated for three model free energy landscapes with anisotropic diffusion. Where exact coordinates can be obtained from Kramers-Langer-Berezhkovskii-Szabo theory, results from the new method agree with the exact results. We also examine characteristics of systems where the proposed method fails. We show how dynamical self-consistency is related (through the Chapman-Kolmogorov equation) to the earlier isocommittor criterion, which is based on longer paths.

Peters, Baron; Bolhuis, Peter G.; Mullen, Ryan G.; Shea, Joan-Emma

2013-02-01

23

Reaction coordinates, one-dimensional Smoluchowski equations, and a test for dynamical self-consistency.  

PubMed

We propose a method for identifying accurate reaction coordinates among a set of trial coordinates. The method applies to special cases where motion along the reaction coordinate follows a one-dimensional Smoluchowski equation. In these cases the reaction coordinate can predict its own short-time dynamical evolution, i.e., the dynamics projected from multiple dimensions onto the reaction coordinate depend only on the reaction coordinate itself. To test whether this property holds, we project an ensemble of short trajectory swarms onto trial coordinates and compare projections of individual swarms to projections of the ensemble of swarms. The comparison, quantified by the Kullback-Leibler divergence, is numerically performed for each isosurface of each trial coordinate. The ensemble of short dynamical trajectories is generated only once by sampling along an initial order parameter. The initial order parameter should separate the reactants and products with a free energy barrier, and distributions on isosurfaces of the initial parameter should be unimodal. The method is illustrated for three model free energy landscapes with anisotropic diffusion. Where exact coordinates can be obtained from Kramers-Langer-Berezhkovskii-Szabo theory, results from the new method agree with the exact results. We also examine characteristics of systems where the proposed method fails. We show how dynamical self-consistency is related (through the Chapman-Kolmogorov equation) to the earlier isocommittor criterion, which is based on longer paths. PMID:23406097

Peters, Baron; Bolhuis, Peter G; Mullen, Ryan G; Shea, Joan-Emma

2013-02-01

24

Improving brush polymer infrared one-dimensional photonic crystals via linear polymer additives.  

PubMed

Brush block copolymers (BBCPs) enable the rapid fabrication of self-assembled one-dimensional photonic crystals with photonic band gaps that are tunable in the UV-vis-IR, where the peak wavelength of reflection scales with the molecular weight of the BBCPs. Due to the difficulty in synthesizing very large BBCPs, the fidelity of the assembled lamellar nanostructures drastically erodes as the domains become large enough to reflect IR light, severely limiting their performance as optical filters. To overcome this challenge, short linear homopolymers are used to swell the arrays to ?180% of the initial domain spacing, allowing for photonic band gaps up to ?1410 nm without significant opacity in the visible, demonstrating improved ordering of the arrays. Additionally, blending BBCPs with random copolymers enables functional groups to be incorporated into the BBCP array without attaching them directly to the BBCPs. The addition of short linear polymers to the BBCP arrays thus offers a facile means of improving the self-assembly and optical properties of these materials, as well as adding a route to achieving films with greater functionality and tailorability, without the need to develop or optimize the processing conditions for each new brush polymer synthesized. PMID:25373000

Macfarlane, Robert J; Kim, Bongkeun; Lee, Byeongdu; Weitekamp, Raymond A; Bates, Christopher M; Lee, Siu Fung; Chang, Alice B; Delaney, Kris T; Fredrickson, Glenn H; Atwater, Harry A; Grubbs, Robert H

2014-12-17

25

Polymer-loaded propagating modes on a one-dimensional photonic crystal  

PubMed Central

We numerically and experimentally demonstrate that a polymer film-coated one-dimensional photonic crystal (1DPC) can sustain transverse electric (TE) polarized modes without the limit of guided layer's thickness. Our results indicate that two propagating modes are existing inside the polymer film, the first one is the TE polarized Bloch surface wave, and the second one is the TE polarized guided mode. Here in, the evolution of these two modes with change in the polymer film thickness is presented. Our numerical simulation results are in well-agreement with the experimental data obtained using back focal plane imaging. PMID:24753624

Han, Lu; Zhang, Douguo; Chen, Yikai; Wang, Ruxue; Zhu, Liangfu; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

2014-01-01

26

Polymer-loaded propagating modes on a one-dimensional photonic crystal  

SciTech Connect

We numerically and experimentally demonstrate that a polymer film-coated one-dimensional photonic crystal (1DPC) can sustain transverse electric (TE) polarized modes without the limit of guided layer's thickness. Our results indicate that two propagating modes are existing inside the polymer film, the first one is the TE polarized Bloch surface wave, and the second one is the TE polarized guided mode. Here in, the evolution of these two modes with change in the polymer film thickness is presented. Our numerical simulation results are in well-agreement with the experimental data obtained using back focal plane imaging.

Han, Lu; Zhang, Douguo, E-mail: dgzhang@ustc.edu.cn; Chen, Yikai; Wang, Ruxue; Zhu, Liangfu; Wang, Pei; Ming, Hai; Lakowicz, Joseph R., E-mail: jlakowicz@som.umaryland.edu [Department of Optics and Optical Engineering, Institute of Photonics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Badugu, Ramachandram [Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 (United States)

2014-02-10

27

Crystal structure of a one-dimensional helical-type silver(I) coordination polymer: catena-poly[[silver(I)-?-N-(pyridin-4-ylmeth­yl)pyridine-3-amine-?2 N:N?] nitrate dimethyl sulfoxide disolvate  

PubMed Central

The asymmetric unit of the title compound, {[Ag(C11H11N3)]NO3·2(CH3)2SO}n, comprises one AgI atom, one N-(pyridine-4-ylmeth­yl)pyridine-3-amine ligand, one nitrate anion and two dimethyl sulfoxide mol­ecules. The AgI atoms are bridged by two pyridine N atoms from two symmetry-related ligands, forming a helical chain and adopting a slightly distorted linear coordination geometry [N—Ag—N = 175.37?(8)°]. The helical chain, with a pitch length of 16.7871?(8)?Å, propagates along the b-axis direction. In the crystal, symmetry-related right- and left-handed helical chains are alternately arranged via Ag?Ag inter­actions [3.4145?(4)?Å] and ?–? stacking inter­actions [centroid–centroid distance = 3.650?(2)?Å], resulting in the formation of a two-dimensional supra­molecular network extending parallel to (100). Weak Ag?O [2.775?(2), 3.169?(4) and 2.690?(2)?Å] inter­actions, as well as several N—H?O and C—H?O hydrogen-bonding inter­actions, contribute to the stabilization of the crystal structure. Parts of the dimethyl sulfoxide solvent molecule are disordered over two sets of sites in a 0.937?(3):0.063?(3) ratio. PMID:25552978

Moon, Bokhee; Jeon, Youngeun; Moon, Suk-Hee; Park, Ki-Min

2014-01-01

28

Fresnel lenses fabricated by femtosecond laser micromachining on polymer one-dimensional photonic crystal  

NASA Astrophysics Data System (ADS)

We report the fabrication of micro-Fresnel lenses by femtosecond laser surface ablation on one-dimensional (1-D) polymer photonic crystals. This device is designed to focus the transmitted wavelength (520 nm) of the photonic crystal and filter the wavelengths corresponding to the photonic band-gap region (centered at 630 nm, ranging from 530 to 700 nm). Integration of such devices in a wavelength selective light harvesting and filtering microchip is envisaged.

Guduru, Surya S. K.; Scotognella, Francesco; Criante, Luigino; Vazquez, Rebeca Martinez; Ramponi, Roberta; Vishnubhatla, Krishna Chaitanya

2014-07-01

29

Fluorescence excitation enhancement by Bloch surface wave in all-polymer one-dimensional photonic structure  

NASA Astrophysics Data System (ADS)

We demonstrate photoluminescence excitation enhancement in an all-polymer flexible one-dimensional photonic crystal structure capped with a fluorescent organic ultrathin film. When optical matching conditions between the excitation beam and the Bloch Surface Wave mode supported by the photonic structure are achieved, a ten times enhancement of the photoluminescence is observed. We notice that in these systems luminescence signal reinforcement is achieved by increasing the pump efficiency with no need of spectral resonance to the emission of the chosen fluorophore. All these features make these systems suitable candidates for easy, flexible, and cheap fluorescent sensing.

Fornasari, L.; Floris, F.; Patrini, M.; Canazza, G.; Guizzetti, G.; Comoretto, D.; Marabelli, F.

2014-08-01

30

Fluorescence excitation enhancement by Bloch surface wave in all-polymer one-dimensional photonic structure  

SciTech Connect

We demonstrate photoluminescence excitation enhancement in an all-polymer flexible one-dimensional photonic crystal structure capped with a fluorescent organic ultrathin film. When optical matching conditions between the excitation beam and the Bloch Surface Wave mode supported by the photonic structure are achieved, a ten times enhancement of the photoluminescence is observed. We notice that in these systems luminescence signal reinforcement is achieved by increasing the pump efficiency with no need of spectral resonance to the emission of the chosen fluorophore. All these features make these systems suitable candidates for easy, flexible, and cheap fluorescent sensing.

Fornasari, L.; Floris, F.; Patrini, M.; Guizzetti, G.; Marabelli, F., E-mail: franco.marabelli@unipv.it [Dipartimento di Fisica, Università degli Studi di Pavia, via Bassi 6, 27100 Pavia (Italy); Canazza, G.; Comoretto, D. [Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, via Dodecaneso 31, 16146 Genova (Italy)

2014-08-04

31

Pseudo one-dimensional analysis of polymer electrolyte fuel cell cold-start  

SciTech Connect

This paper investigates the electrochemical kinetics, oxygen transport, and solid water formation in polymer electrolyte fuel cell (PEFC) during cold start. Following [Yo Wang, J. Electrochem. Soc., 154 (2007) B1041-B1048], we develop a pseudo one-dimensional analysis, which enables the evaluation of the impact of ice volume fraction and temperature variations on cell performance during cold-start. The oxygen profile, starvation ice volume fraction, and relevant overpotentials are obtained. This study is valuable for studying the characteristics of PEFC cold-start.

Mukherjee, Partha P [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wang, Yun [NON LANL; Mishlera, Jeff [NON LANL

2009-01-01

32

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers  

NASA Astrophysics Data System (ADS)

Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the nonlinear local excitations such as solitons, polarons, and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here, we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA, the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge).

Choi, A.; Kim, K. H.; Hong, S. J.; Goh, M.; Akagi, K.; Kaner, R. B.; Kirova, N. N.; Brazovskii, S. A.; Johnson, A. T.; Bonnell, D. A.; Mele, E. J.; Park, Y. W.

2012-10-01

33

Probing spin-charge relation by magnetoconductance in one-dimensional polymer nanofibers  

NASA Astrophysics Data System (ADS)

Polymer nanofibers are one dimensional (1-D) organic hydrocarbon systems containing conducting polymers where the non-linear local excitations such as solitons, polarons and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge).

Park, Yung Woo

2013-03-01

34

Band structure properties of one-dimensional donor-acceptor model polymers  

NASA Astrophysics Data System (ADS)

The band structures of one-dimensional donor-acceptor (DA) stacks have been studied by means of the crystal orbital formalism based on a semi-empirical INDO approximation. The model polymers are composed of quinhydrone moieties ( 1 and 2) with different mutual orientations of D and A. The DA capability was modified by varying the DA distance within the unit cell as well as the effective electronegativity of the active groups of D and A. An insulator-to-metal transition is predicted for 1 at short DA distance and larger differences in the electronegativities of D and A. An avoided crossing between the highest filled and the lowest unfilled ?( k) curves is encountered in 2 leading to a finite band gap for all studied DA interaction conditions.

Böhm, M. C.; Vogler, H.

1983-04-01

35

Solitons and polarons in quasi-one dimensional conducting polymers and related materials  

SciTech Connect

In recent years it has become increasingly appreciated that fundamentally nonlinear excitations - solitons - play an essential role in an incredible variety of natural systems. These solitons, which frequently exhibit remarkable stability under interactions and perturbations, often dominate the transport, response, or structural properties of the systems in which they occur. In this article, we present an introduction to the solitons that occur in quasi-one-dimensional conducting polymers (synmetals) and related systems. The relevance of this subject to molecular electronic devices is twofold. First, many of these materials have molecular structures similar to possible prototype molecular switches. Second, to understand in detail how a molecular electronic device could work, it is essential to have a broad perspective on the nature of possible excitations in a variety of natural and synthetic molecular materials. 51 references.

Campbell, D.K.

1983-01-01

36

Anomalous enhancement in the infrared phonon intensity of a one-dimensional uneven peanut-shaped C60 polymer  

NASA Astrophysics Data System (ADS)

A one-dimensional (1D) uneven peanut-shaped C60 polymer formed from electron-beam (EB)-induced polymerization of C60 molecules showed an anomalous increase in two characteristic infrared (IR) peak intensities, which are respectively due to the radial and tangential motion of the 1D polymer, when compared to the IR peaks of pristine C60 films. This anomaly was analyzed on the basis of the vibrational van Hove singularity (VHS), using an extended thin-shell elastic model fully considering the effects of periodic radius modulation inherent to the 1D uneven peanut-shaped C60 polymer. We succeeded in explaining the enhancement in the tangential peak intensity by VHS, whereas the origin to cause that in the radial peak intensity is still unclear.

Onoe, J.; Takashima, A.; Ono, S.; Shima, H.; Nishii, T.

2012-05-01

37

Quantum Chemical Investigation of meta-Xylylene Based One-Dimensional Polymer Chain.  

PubMed

We have investigated unsubstituted and methyl substituted polyradical chains of meta-xylylene by using density functional theory-broken symmetry methodology (DFT-BS). Optimization of geometry in the high-spin and low-spin states have been done at B3LYP/6-31G(d,p) and M06-2X/6-31G(d,p) levels in unrestricted methodology. Single-point calculations on the high-spin optimized geometries have been done by using the 6-311G(d,p) basis set. Each polyradical has been found to be nonplanar with a high-spin ground state. Each has a coupling constant larger than thermal energy. For each group of polyradicals, the coupling constant has been found to exponentially decrease with increase in the number of phenylene groups. The B3LYP infinite chain limit has been estimated for both the unsubstituted and substituted polyradicals. The individual inter-radical-site coupling constants have been estimated for the triradicals and tetraradicals using HDVV Hamiltonian in ORCA 3.0.1 code. These are also generally large and positive, revealing a strong intersite ferromagnetic interaction. The intersite coupling constant too decreases with increasing distance between the radical centers. Finally, we have used CRYSTAL09 package for calculations on the infinitely long one-dimensional and periodic polyradical chains. The coupling constants estimated from the periodic calculations are quite large at about 500 cm(-1) and somewhat greater than the limiting values calculated for the polyradicals with an increasing number of phenylene groups. This happens as the individual polyradicals of increasing size progressively deviate from periodicity, and thereby lessens the strength of through-bond spin-spin coupling. The calculated band gap of ?4.5 eV indicates that the infinitely long one-dimensional chains must be ferromagnetic and electron insulators. PMID:25695126

Pal, Arun K; Hansda, Shekhar; Datta, Sambhu N

2015-03-12

38

Transition State Theory Approach to Polymer Escape from a One Dimensional Potential Well  

E-print Network

The rate of escape of an ideal bead-spring polymer in a symmetric double-well potential is calculated using transition state theory (TST) and the results compared with direct dynamical simulations. The minimum energy path of the transitions becomes flat and the dynamics diffusive for long polymers making the Kramers-Langer estimate poor. However, TST with dynamical corrections based on short time trajectories started at the transition state gives rate constant estimates that agree within a factor of two with the molecular dynamics simulations over a wide range of bead coupling constants and polymer lengths. The computational effort required by the TST approach does not depend on the escape rate and is much smaller than that required by molecular dynamics simulations.

Mökkönen, Harri; Ala-Nissila, Tapio; Jónsson, Hannes

2015-01-01

39

Transition State Theory Approach to Polymer Escape from a One Dimensional Potential Well  

E-print Network

The rate of escape of an ideal bead-spring polymer in a symmetric double-well potential is calculated using transition state theory (TST) and the results compared with direct dynamical simulations. The minimum energy path of the transitions becomes flat and the dynamics diffusive for long polymers making the Kramers-Langer estimate poor. However, TST with dynamical corrections based on short time trajectories started at the transition state gives rate constant estimates that agree within a factor of two with the molecular dynamics simulations over a wide range of bead coupling constants and polymer lengths. The computational effort required by the TST approach does not depend on the escape rate and is much smaller than that required by molecular dynamics simulations.

Harri Mökkönen; Timo Ikonen; Tapio Ala-Nissila; Hannes Jónsson

2015-03-25

40

A polymer-based functional pattern on one-dimensional photonic crystals for photon sorting of fluorescence radiation.  

PubMed

In this work we introduce the use of a patterned polymer-based surface functionalization of a one-dimensional photonic crystal (1DPC) for controlling the emission direction of fluorescent proteins (ptA) via coupling to a set of two Bloch Surface Waves (BSW). Each BSW dispersion branch relates to a micrometric region on the patterned 1DPC, characterized by a well defined chemical characteristic. We report on the enhanced and spatially selective excitation of fluorescent ptA, and on the spatially-resolved detection of polarized emitted radiation coupled to specific BSW modes. As a result, we provide an optical multiplexing technique for the angular separation of fluorescence radiated from micrometric regions having different surface properties, even in the case the emitting labels are spectrally identical. This working principle can be advantageously extended to a multi-step nanometric relief structure for self-referencing biosensing or frequency-multiplexed fluorescence detection. PMID:22418554

Ballarini, Mirko; Frascella, Francesca; De Leo, Natascia; Ricciardi, Serena; Rivolo, Paola; Mandracci, Pietro; Enrico, Emanuele; Giorgis, Fabrizio; Michelotti, Francesco; Descrovi, Emiliano

2012-03-12

41

Static fluctuations of a thick one-dimensional interface in the 1+1 directed polymer formulation: numerical study.  

PubMed

We study numerically the geometrical and free-energy fluctuations of a static one-dimensional (1D) interface with a short-range elasticity, submitted to a quenched random-bond Gaussian disorder of finite correlation length ?>0 and at finite temperature T. Using the exact mapping from the static 1D interface to the 1+1 directed polymer (DP) growing in a continuous space, we focus our analysis on the disorder free energy of the DP end point, a quantity which is strictly zero in the absence of disorder and whose sample-to-sample fluctuations at a fixed growing time t inherit the statistical translation invariance of the microscopic disorder explored by the DP. Constructing a new numerical scheme for the integration of the Kardar-Parisi-Zhang evolution equation obeyed by the free energy, we address numerically the time and temperature dependence of the disorder free-energy fluctuations at fixed finite ?. We examine, on one hand, the amplitude D[over ?](t) and effective correlation length ?[over ?](t) of the free-energy fluctuations and, on the other hand, the imprint of the specific microscopic disorder correlator on the large-time shape of the free-energy two-point correlator. We observe numerically the crossover to a low-temperature regime below a finite characteristic temperature T(c)(?), as previously predicted by Gaussian variational method computations and scaling arguments and extensively investigated analytically in [Phys. Rev. E 87, 042406 (2013)]. Finally, we address numerically the time and temperature dependence of the roughness B(t), which quantifies the DP end point transverse fluctuations, and we show how the amplitude D[over ?](?)(T,?) controls the different regimes experienced by B(t)-in agreement with the analytical predictions of a DP toy model approach. PMID:23848695

Agoritsas, Elisabeth; Lecomte, Vivien; Giamarchi, Thierry

2013-06-01

42

Porphyrin coordination polymer nanospheres and nanorods  

DOEpatents

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2012-12-04

43

Mn4 single-molecule-magnet-based polymers of a one-dimensional helical chain and a three-dimensional network: syntheses, crystal structures, and magnetic properties.  

PubMed

Two Mn(4) single-molecule-magnet (SMM)-based coordination polymers, {[Mn(4)O(salox)(3)(N(3))(3)(DMF)(2)(H(2)O)(dpp)]·0.5MeOH}(n) (1·0.5MeOH; H(2)salox = salicylaldoxime; dpp = 1,3-di-4-pyridylpropane; DMF = N,N-dimethylformamide) and {[Mn(4)O(Me-salox)(3)(N(3))(3)(dpp)(1.5)]·1.5Et(2)O}(n) (2·1.5Et(2)O; Me-H(2)salox = hydroxyphenylethanone oxime), are self-assembled from Mn(ClO(4))(2)·6H(2)O/H(2)salox and Mn(ClO(4))(2)·6H(2)O/Me-H(2)salox systems with dpp and NaN(3) in DMF/MeOH, respectively. Both compounds comprise a mixed-valence tetranuclear manganese core, [Mn(II)Mn(III)(3)O](9+), which serves as a building unit for subsequent assembly via oximate and azido ligands. The flexible dpp ligand links with a Mn(4) unit, leading to the formation of a one-dimensional helical structure in 1·0.5MeOH and a three-dimensional pcu network in 2·1.5Et(2)O. The magnetic data analysis shows that antiferromagnetic interactions within the Mn(4) units resulted in S = (3)/(2) and (7)/(2) ground states for 1·0.5MeOH and 2·1.5Et(2)O, respectively. Both compounds show SMM behavior, as evidenced by frequency-dependent out-of-phase signals in alternating-current magnetic susceptibility and magnetic hysteresis loop studies with an energy barrier of U(eff) = 37 K for 2·1.5Et(2)O. PMID:23215243

Tsai, Hui-Lien; Yang, Chen-I; Wernsdorfer, Wolfgang; Huang, Siang-Hua; Jhan, Siang-Yu; Liu, Ming-Hsuan; Lee, Gene-Hsiang

2012-12-17

44

Anomaly in the electric resistivity of one-dimensional uneven peanut-shaped C60 polymer film at a low temperature  

NASA Astrophysics Data System (ADS)

We performed in situ four-probe measurements of the current-voltage characteristics of one-dimensional (1D) uneven peanut-shaped C60 polymer films in the temperature range 30-350 K under ultrahigh vacuum conditions (2 × 10-7 Pa). Arrhenius plots of the film resistance with respect to temperature showed two different electron-conduction mechanisms. While electrons are conducted via a thermal excitation hopping at temperatures above 160 K, the resistivity of the 1D polymer film exhibits an anomalous behavior that becomes fluctuated at a given value in the temperature range 40-90 K and decreases at temperatures below 40 K.

Ryuzaki, Soh; Onoe, Jun

2014-03-01

45

Anomaly in the electric resistivity of one-dimensional uneven peanut-shaped C{sub 60} polymer film at a low temperature  

SciTech Connect

We performed in situ four-probe measurements of the current-voltage characteristics of one-dimensional (1D) uneven peanut-shaped C{sub 60} polymer films in the temperature range 30–350?K under ultrahigh vacuum conditions (2?×?10{sup ?7}?Pa). Arrhenius plots of the film resistance with respect to temperature showed two different electron-conduction mechanisms. While electrons are conducted via a thermal excitation hopping at temperatures above 160?K, the resistivity of the 1D polymer film exhibits an anomalous behavior that becomes fluctuated at a given value in the temperature range 40–90?K and decreases at temperatures below 40?K.

Ryuzaki, Soh; Onoe, Jun, E-mail: jonoe@nr.titech.ac.jp [Research Laboratory for Nuclear Reactors and Department of Nuclear Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8550 (Japan)

2014-03-17

46

An innovative method for coordinate measuring machine one-dimensional self-calibration with simplified experimental process  

NASA Astrophysics Data System (ADS)

In this paper, an innovative method for CMM (Coordinate Measuring Machine) self-calibration is proposed. In contrast to conventional CMM calibration that relies heavily on a high precision reference standard such as a laser interferometer, the proposed calibration method is based on a low-cost artefact which is fabricated with commercially available precision ball bearings. By optimizing the mathematical model and rearranging the data sampling positions, the experimental process and data analysis can be simplified. In mathematical expression, the samples can be minimized by eliminating the redundant equations among those configured by the experimental data array. The section lengths of the artefact are measured at arranged positions, with which an equation set can be configured to determine the measurement errors at the corresponding positions. With the proposed method, the equation set is short of one equation, which can be supplemented by either measuring the total length of the artefact with a higher-precision CMM or calibrating the single point error at the extreme position with a laser interferometer. In this paper, the latter is selected. With spline interpolation, the error compensation curve can be determined. To verify the proposed method, a simple calibration system was set up on a commercial CMM. Experimental results showed that with the error compensation curve uncertainty of the measurement can be reduced to 50%.

Fang, Cheng; Butler, David Lee

2013-05-01

47

Designer coordination polymers: dimensional crossover architectures and proton conduction.  

PubMed

Coordination polymers (CPs) have large degrees of freedom in framework compositions and in the structures and environment of the inner pores. This review focuses on the recent significant progress achieved by controlling these degrees of freedom. Two breakthroughs are reviewed for constructing sophisticated structures of CP frameworks, especially in dimensional crossover regions. The first is the synthesis of quasi one-dimensional halogen-bridged coordinative tubes by applying state-of-the-art techniques of coordination chemistry. The electronic state of the coordinative tube was studied by structural, spectroscopic and theoretical methods and found to be distinct from conventional one-dimensional systems. The second breakthrough is the achievement of a quasi-two-dimensional architecture by combining Langmuir-Blodgett and layer-by-layer methods. Two-dimensional LB CP films were prepared on liquid; the films were stacked layer by layer, and a crystalline quasi-two-dimensional structure was constructed. This review also covers the design of the environment of the inner pore, where hydrogen bond networks with various acidic sites were modified. By appropriate design of the hydrogen bond network, proton-conductive CPs are invented, which are summarized in this review. Types of proton donor sites are discussed and classified, and superprotonic conductive CPs were achieved in these investigations. These results will provide new strategies for constructing functional materials for smart devices. PMID:23817780

Yamada, Teppei; Otsubo, Kazuya; Makiura, Rie; Kitagawa, Hiroshi

2013-08-21

48

Ordered alignment of a one-dimensional ?-conjugated nickel bis(dithiolene) complex polymer produced via interfacial reactions.  

PubMed

A liquid-liquid interfacial synthesis using 1,2,4,5-benzenetetrathiol and nickel(II) ions produced a thin black film of a ?-conjugated polymer featuring the nickel bis(dithiolene) motif. Its ordered structure was not originally identified due to its amorphicity; however, it was observed to align regularly on a highly oriented pyrolytic graphite substrate using scanning tunnelling microscopy. PMID:24777066

Matsuoka, Ryota; Sakamoto, Ryota; Kambe, Tetsuya; Takada, Kenji; Kusamoto, Tetsuro; Nishihara, Hiroshi

2014-08-01

49

Unlocking the functional properties in one-dimensional MoSI cluster polymers by doping and photoinduced charge transfer.  

PubMed

To improve functionalization of MoSI cluster polymers we have studied the effects of adsorption doping on the electrical transport, bundling, and optical absorption spectra. Doping results both in enhanced conductivity and aggregated bundles in dispersion. The different electronic properties of different bundle diameters can be ascribed to self-doping during the synthesis. Furthermore, doping shifts the characteristic absorption peaks and transfers oscillator strength to lower energies. Femtosecond optical spectroscopy shows that the spectral signature of adsorption and self-doping indeed originates from the population of electronic levels that are empty or absent in the undoped sample. The large spectral shifts and long lifetimes of photoinduced charges suggest efficient localization. PMID:25562470

Topolovsek, Peter; Gadermaier, Christoph; Vengust, Damjan; Strojnik, Martin; Strle, Jure; Mihailovic, Dragan

2015-02-11

50

A white phosphorescent coordination polymer with Cu2I2 alternating units linked by benzo-18-crown-6.  

PubMed

A new approach has been illustrated for the development of stable, efficient, and environmentally "friendly" white phosphorescent materials. Under mild conditions, a new one-dimensional coordination polymer has been prepared from benzo-18-crown-6 with CuI in the presence of KI, which is capable of emitting direct white light in the solid state. PMID:24886808

Wu, Fengshou; Tong, Hongbo; Li, Zaoying; Lei, Wang; Liu, Li; Wong, Wai-Yeung; Wong, Wai-Kwok; Zhu, Xunjin

2014-09-01

51

Cluster-based Magnetic Porous Coordination Polymers  

Microsoft Academic Search

The creation of a porous magnet is a long-sought academic goal since magnetism and porosity are hostile to one another. While long-range magnetic ordering needs spin carriers of short separation through short bridges, porosity relies on the use of extended connecting ligands. Here, we will give a survey of the cluster-based magnetic porous coordination polymers, i.e., 0-D MPCPs, according to

XIANG Sheng-Chang; WANG Xin

52

Coordination polymers of uranium(IV) terephthalates.  

PubMed

A series of tetravalent uranium terephthalates has been solvothermally synthesized in the solvent N,N-dimethylformamide (DMF) at temperature 100-150 °C with different water amounts. Composition diagrams have been determined for the U(4+) metallic cation in the presence of terephthalic acid, and their crystal structures revealed the occurrence of two- or three-dimensional coordination polymers. In the absence of water, a mixture of two polytypes T-U(2)Cl(2)(bdc)(3)(DMF)(4) (1) and M-U(2)Cl(2)(bdc)(3)(DMF)(4) (2) has been identified at low temperature (100-110 °C) for bdc/U = 1-4 (bdc = terephthalate linker). Their structures are built up from isolated uranium centers in nine-fold coordination, surrounded by 6 carboxyl oxygen atoms, 2 oxygen atoms coming from DMF molecules and one chlorine atom. The uranium cations are linked to each other through the bdc ligand in order to generate a 3D framework. By increasing the temperature (130-150 °C), a layered like compound has been isolated, U(2)(bdc)(4)(DMF)(4) (3). It is composed of discrete actinide centers in ten-fold coordination, with 8 carboxyl oxygen atoms and 2 oxygen atoms from DMF molecules. The connection of the UO10 units with the bdc linkers generates 2D sheets. When a controlled amount of water is added to the reaction medium, the crystallization of the UiO-66-like U(6)O(4)(OH)(4)(H(2)O)(6)(bdc)(6)·10DMF solid (containing a hexanuclear sub-unit) is observed for temperature 110-120 °C and the H(2)O/U molar ratio in the range of 2-10. At higher temperature (140-150 °C), a distinct phase appeared, U(2)O(2)(bdc)(2)(DMF) (4), which consists of infinite chains of uranium centers, linked to each other via the bdc ligands. Higher water contents led to the formation of urania UO(2). PMID:25428593

Falaise, Clément; Assen, Ayalew; Mihalcea, Ionut; Volkringer, Christophe; Mesbah, Adel; Dacheux, Nicolas; Loiseau, Thierry

2015-02-14

53

Coordination polymer nanobelts for nucleic acid detection  

NASA Astrophysics Data System (ADS)

Herein, coordination polymer nanobelts (CPNBs) were prepared rapidly and on a large scale, by directly mixing aqueous AgNO3 solution and an ethanol solution of 4, 4'-bipyridine at room temperature. The application of such CPNBs as a fluorescent sensing platform for nucleic acid detection was further explored. CPNB is a ?-rich structure, the strong ?-? stacking interactions between unpaired DNA bases and CPNB leads to adsorption of fluorescently labeled single-stranded DNA (ssDNA) accompanied by 66% fluorescence quenching. However, the presence of target ssDNA will hybridize with the probe. The resultant helix cannot be adsorbed by CPNB due to its rigid conformation and the absence of unpaired DNA bases. Thus, a significant fluorescence enhancement, 73% fluorescence recovery, was observed in DNA detection as long as the target exists. The present system has excellent sensitivity; a substantial fluorescence enhancement was observed when the concentration of the target was as low as 5 nM. It also exhibits outstanding discrimination ability down to a single-base mismatch.

Luo, Yonglan; Liao, Fang; Lu, Wenbo; Chang, Guohui; Sun, Xuping

2011-05-01

54

Formation process and electron-beam incident energy dependence of one-dimensional uneven peanut-shaped C60 polymer studied using in situ high-resolution infrared spectroscopy and density-functional calculations  

NASA Astrophysics Data System (ADS)

A 3 kV electron-beam irradiation of a C60 film gives rise to formation of one-dimensional (1D) uneven peanut-shaped C60 polymer with a cross-linked structure close to that of the P08 C120 stable isomer obtained from the general Stone-Wales rearrangement. In this study, we examined the evolution of infrared (IR) spectra of C60 films with respect to electron beam (EB) irradiation time, using in situ high-resolution IR spectroscopy and first-principles density-functional calculations, and found semi-quantitatively that the 1D uneven peanut-shaped C60 polymer is formed via intermediate polymers with a cross-linkage close to that of P04 and P06 C120 isomers obtained from GWS rearrangement. In addition, we examined the dependence of EB-induced C60 polymerization on an incident energy of EB in the range 3-7 kV. IR spectra obtained for 5 and 7 kV EB irradiation of C60films showed the same product as for 3 kV EB irradiation. However, when 5 and 7 kV EBs continued to irradiate C60 films for a long time after the polymer formation, the 1D peanut-shaped polymer did not proceed to become 1D polymers with a more coalesced linkage than that of the P08 one but was destroyed to become amorphous carbons.

Takashima, Akito; Nishii, Toshiaki; Onoe, Jun

2012-12-01

55

Photocatalytic activity of PANI loaded coordination polymer composite materials: Photoresponse region extension and quantum yields enhancement via the loading of PANI nanofibers on surface of coordination polymer  

SciTech Connect

To enhance photocatalytic property of coordination polymer in visible light region, polyaniline (PANI) loaded coordination polymer photocatalyst was synthesized through in-situ chemical oxidation of aniline on the surface of coordination polymer. The photocatalytic activity of PANI loaded coordination polymer composite material for degradation of Rhodamine B (RhB) was investigated. Compared with pure coordination polymer photocatalyst, which can decompose RhB merely under UV light irradiation, PANI loaded coordination polymer photocatalyst displays more excellent photocatalytic activity in visible light region. Furthermore, PANI loaded coordination polymer photocatalyst exhibits outstanding stability during the degradation of RhB. - Graphical abstract: PANI loaded coordination polymer composite material, which displays excellent photocatalytic activity under visible light was firstly synthesized through in-situ chemical oxidation of aniline on surface of coordination polymer. Display Omitted - Highlights: • This PANI loaded coordination polymer composite material represents the first conductive polymer loaded coordination polymer composite material. • PANI/coordination polymer composite material displays more excellent photocatalytic activity for the degradation of MO in visible light region. • The “combination” of coordination polymer and PANI will enable us to design high-activity, high-stability and visible light driven photocatalyst in the future.

Cui, Zhongping; Qi, Ji; Xu, Xinxin, E-mail: xuxx@mail.neu.edu.cn; Liu, Lu; Wang, Yi, E-mail: yiwang67@163.com

2013-09-15

56

Crystal structures and luminescent properties of lanthanide nitrate coordination polymers with structurally related amide type bridging podands  

SciTech Connect

A one-dimensional linear chain coordination polymer [ErL{sup I}(NO{sub 3}){sub 3}(CH{sub 3}CO{sub 2}Et)]{sub n} (L{sup I}=1,2-bis{l_brace}[(2'-furfurylaminoformyl)phenoxyl]methyl{r_brace}benzene) and a one-dimensional zig-zag coordination polymer {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n} (L{sup II}=1,2-bis{l_brace}[2'-(2-pyridylmethylaminoformyl)phenoxyl]methyl{r_brace}benzene) were assembled by two structurally related bridging podands L{sup I} and L{sup II} which have uniform skeleton and different terminal groups. In {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n}, the neutral chains were linked by the hydrogen bonding interactions between the free and coordinated water molecules from two different directions to interpenetrate into a 3D supramolecular structure. At the same time, the luminescent properties of the solid Tb(III) nitrate complexes of these podands were investigated at room temperature. The lowest triplet state energy levels T{sub 1} of the podands L{sup I} and L{sup II} indicate that the triplet state energy levels of the antennae are both above the lowest excited resonance level of {sup 5}D{sub 4} of Tb{sup 3+} ion. Thus the absorbed energy could be transferred from ligands to the central Tb{sup 3+} ions. And the influence of the hydrogen bonding on the luminescence efficiencies of the coordination polymers was also discussed. -- Graphical Abstract: Two one-dimensional lanthanide coordination polymers were assembled by two structurally related bridging podands, and the effects of the structures on luminescent properties of the solid Tb(III) nitrate complexes were investigated. Display Omitted Research highlights: > Two structurally related amide type bridging ligands were designed and synthesized. > Two one dimensional lanthanide nitrate coordination polymers were obtained. > The structure effects on luminescent properties of the terbium complexes were discussed.

Wang, Qing; Yan, Xuhuan; Zhang, Hongrui; Liu, Weisheng [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang, Yu, E-mail: tangyu@lzu.edu.c [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tan, Minyu [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2011-01-15

57

Nanoscale coordination polymers for anticancer drug delivery  

NASA Astrophysics Data System (ADS)

This dissertation reports the synthesis and characterization of nanoscale coordination polymers (NCPs) for anticancer drug delivery. Nanoparticles have been explored in order to address the limitations of small molecule chemotherapeutics. NCPs have been investigated as drug delivery vehicles as they can exhibit the same beneficial properties as the bulk metal-organic frameworks as well as interesting characteristics that are unique to nanomaterials. Gd-MTX (MTX = methotrexate) NCPs with a MTX loading of 71.6 wt% were synthesized and stabilized by encapsulation within a lipid bilayer containing anisamide (AA), a small molecule that targets sigma receptors which are overexpressed in many cancer tissues. Functionalization with AA allows for targeted delivery and controlled release to cancer cells, as shown by enhanced efficacy against leukemia cells. The NCPs were doped with Ru(bpy)32+ (bpy = 2,2'-bipyridine), and this formulation was utilized as an optical imaging agent by confocal microscopy. NCPs containing the chemotherapeutic pemetrexed (PMX) were synthesized using different binding metals. Zr-based materials could not be stabilized by encapsulation with a lipid bilayer, and Gd-based materials showed that PMX had degraded during synthesis. However, Hf-based NCPs containing 19.7 wt% PMX were stabilized by a lipid coating and showed in vitro efficacy against non-small cell lung cancer (NSCLC) cell lines. Enhanced efficacy was observed for formulations containing AA. Additionally, NCP formulations containing the cisplatin prodrug disuccinatocisplatin were prepared; one of these formulations could be stabilized by encapsulation within a lipid layer. Coating with a lipid layer doped with AA rendered this formulation an active targeting agent. The resulting formulation proved more potent than free cisplatin in NSCLC cell lines. Improved NCP uptake was demonstrated by confocal microscopy and competitive binding assays. Finally, a Pt(IV) oxaliplatin prodrug was synthesized and incorporated in different NCPs using various binding metals. A moderate drug loading of 44.9 wt% was determined for Zr-based NCPs. This drug loading, along with a diameter less than 200 nm, make these particles promising candidates for further stabilization via lipid encapsulation.

Phillips, Rachel Huxford

58

One-Dimensional Heat Equation  

NSDL National Science Digital Library

Using Maple or Mathmatica, the learner will study the symbolic form and graphical representation of the approximate solutions of the one-dimensional heat equation with various boundary and initial conditions.

David Smith

59

Photoluminescent lead(II) coordination polymers stabilised by bifunctional organoarsonate ligands  

NASA Astrophysics Data System (ADS)

Four lead(II) coordination polymers were isolated under hydro(solvo)thermal conditions. The applied synthetic methodology takes advantage of the coordination behaviour of a new bifunctional organoarsonate ligand, 4-(1, 2, 4-triazol-4-yl)phenylarsonic acid (H2TPAA) and involves the variation of lead(II) reactants, metal/ligand mole ratios, and solvents. The constitutional composition of the four lead(II) coordination polymers can be formulated as [Pb2(TPAA)(HTPAA)(NO3)]·6H2O (1), [Pb2(TPAA)(HTPAA)2]·DMF·0.5H2O (DMF = N, N-Dimethylformamide) (2), [Pb2Cl2(TPAA)H2O] (3), and [Pb3Cl(TPAA)(HTPAA)2H2O]Cl (4). The compounds were characterized by single-crystal and powder x-ray diffraction techniques, thermogravimetric analyses, infra-red spectroscopy, and elemental analyses. Single-crystal x-ray diffraction reveals that 1 and 2 represent two-dimensional (2D) layered structures whilst 3 and 4 form three-dimensional (3D) frameworks. The structures of 1, 2, and 4 contain one-dimensional (1D) {PbII/AsO3} substructures, while 3 is composed of 2D {PbII/AsO3} arrays. Besides their interesting topologies, 1–4 all exhibit photoluminescence properties in the solid state at room temperature.

Lin, Jian-Di; Onet, Camelia I.; Schmitt, Wolfgang

2015-04-01

60

Homochiral coordination polymers constructed from aminocarboxylate derivates: Effect of bipyridine on the amidation reaction  

NASA Astrophysics Data System (ADS)

Using aminocarboxylate derivates (S)-N-(4-cyanobenzoic)-glutamic acid (denoted as cbg, 1a) and (S)-N-(4-nitrobenzoic)-glutamic acid (denoted as nbg, 1b) as chiral ligands, five new homochiral coordination polymers formulated as [Cu(cbg)(H2O)2]n (3), [Cu(cbop)2(4,4'-bipy)(H2O)]n (4) (cbop=(S)-N-(4-cyanobenzoic)-5-oxoproline, 4,4'-bipy=4,4'-bipyridine), {[Cu(nbop)2(4,4'-bipy)]·4H2O}n (5) (nbop=(S)-N-(4-nitrobenzoic)-5-oxoproline), {[Cd(nbop)2(4,4'-bipy)]·2H2O}n (6), and [Ni(nbop)2(4,4'-bipy)(H2O)2]n (7) have been hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction study reveals that the original chirality of aminocarboxylate derivates is maintained in all these complexes. Complexes 3, 4, and 7 are one-dimensional infinite chain coordination polymers, while complexes 5 and 6 possess two-dimensional network structures. In situ cyclization of 1a and 1b was taken place in the formation of complexes 4-7, which may be due to the competition of 4,4'-bipyridine with chiral ligands during the coordination process. Preliminary optical behavior investigation indicates that ligands 1a, 1b, and complexes 6, 7 are nonlinear optical active.

Chen, Jianshan; Sheng, Tianlu; Hu, Shengmin; Xiang, Shengchang; Fu, Ruibiao; Zhu, Qilong; Wu, Xintao

2012-08-01

61

Self-consistent field theory of tethered polymers: One dimensional, three dimensional, strong stretching theories and the effects of excluded-volume-only interactions  

NASA Astrophysics Data System (ADS)

We examine end-tethered polymers in good solvents, using one- and three-dimensional self-consistent field theory, and strong stretching theories. We also discuss different tethering scenarios, namely, mobile tethers, fixed but random ones, and fixed but ordered ones, and the effects and important limitations of including only binary interactions (excluded volume terms). We find that there is a "mushroom" regime in which the layer thickness is independent of the tethering density, ?, for systems with ordered tethers, but we argue that there is no such plateau for mobile or disordered anchors, nor is there one in the 1D theory. In the other limit of brushes, all approaches predict that the layer thickness scales linearly with N. However, the ?1/3 scaling is a result of keeping only excluded volume interactions: when the full potential is included, the dependence is faster and more complicated than ?1/3. In fact, there does not appear to be any regime in which the layer thickness scales in the combination N?1/3. We also compare the results for two different solvents with each other, and with earlier ? solvent results.

Suo, Tongchuan; Whitmore, Mark D.

2014-11-01

62

Assembly of three coordination polymers based on a sulfonic-carboxylic ligand showing high proton conductivity.  

PubMed

Three new coordination polymers (CPs)/metal-organic frameworks (MOFs) with different structures have been synthesized using 4,8-disulfonyl-2,6-naphthalenedicarboxylic acid (H4L) and metal ions, Cu(2+), Ca(2+) and Cd(2+). The Cu compound features a one-dimensional chain structure, further extending into a 2D layer network through H-bond interactions. Both the Ca and Cd compounds show 3D frameworks with (4,4)-connected PtS-type topology and (3,6)-connected bct-type topology, respectively. These CPs/MOFs all exhibit proton conduction behavior, especially for the Cu compound with a proton conductivity of 3.46 × 10(-3) S cm(-1) at 368 K and 95% relative humidity (RH). Additionally, the activation energy (Ea) has also been investigated to deeply understand the proton-conduction mechanism. PMID:25406590

Zhao, Shu-Na; Song, Xue-Zhi; Zhu, Min; Meng, Xing; Wu, Lan-Lan; Song, Shu-Yan; Wang, Cheng; Zhang, Hong-Jie

2015-01-21

63

Cobalt(II) Coordination Polymer Exhibiting Single-Ion-Magnet-Type Field-Induced Slow Relaxation Behavior.  

PubMed

A one-dimensional cobalt(II) coordination polymer, [Co(btm)2(SCN)2·H2O]n [btm = bis(1H-1,2,4-triazol-1-yl)methane], was synthesized and magnetically characterized. The isolated slightly distorted octahedral Co(II) ion displays field-induced slow relaxation with a big positive axial and a negative rhombic magnetic anisotropy (D = 93.9 cm(-1) and E = -10.5 cm(-1)), and the anisotropy energy barrier is 45.4 K. PMID:25853410

Zhu, Yuan-Yuan; Zhu, Ming-Sheng; Yin, Ting-Ting; Meng, Yin-Shan; Wu, Zong-Quan; Zhang, Yi-Quan; Gao, Song

2015-04-20

64

EXAFS study of some coordination polymers of copper  

NASA Astrophysics Data System (ADS)

The EXAFS spectra for (1) azelaic acid bis phenyl hydrazide, (2) azelaic acid bis 2,4 dinitro phenyl hydrazide and (3) sebacic acid bis phenyl hydrazide coordination polymers of copper were obtained using the EXAFS facility of the Daresbury Laboratory. The EXAFS analysis revealed that copper is surrounded by four nitrogen and two oxygen atoms in the first coordination shell, while the second coordination shell consists of two carbon atoms. This information suggests the octahedral geometry for the repeating units of polymeric complexes, in contrast to the square planar geometry previously proposed.

Deshpande, A. P.

1995-02-01

65

Polymer conformations in internal (polyspherical) coordinates.  

PubMed

The small-amplitude conformational changes in macromolecules can be described by the changes in bond lengths and bond angles. The descriptors of large scale changes are torsions. We present a recursive algorithm, in which a bond vector is explicitly written in terms of these internal, or polyspherical coordinates, in a local frame defined by two other bond vectors and their cross product. Conformations of linear and branched molecules, as well as molecules containing rings can be described in this way. The orientation of the molecule is described by the orientation of a body frame. It is parametrized by the instantaneous rotation angle, and the two angles that parametrize the orientation of the instantaneous rotation axis. The reason not to use more conventional Euler angles is due to the fact that Euler angles are not well-defined in gimbal lock (i.e., when a body axis becomes aligned with its space fixed counter part). The position of the molecule is parametrized by its center of mass. Original and calculated positions are compared for several proteins, containing up to about 100,000 atoms. PMID:20082385

Pesonen, Janne; Henriksson, Krister O E

2010-07-15

66

Intramolecularly coordinated telluroxane clusters and polymers.  

PubMed

The stoichiometrically controlled chlorination of the diarylditelluride (8-Me(2) NC(10) H(6) Te)(2) with SO(2) Cl(2) afforded the aryltellurinyl chloride 8-Me(2) NC(10) H(6) TeCl (1) and the aryltellurium trichloride 8-Me(2) NC(10) H(6) TeCl(3) (2). Alternatively, 1 was obtained by the reaction of the aryltellurenyl diethyldithiacarbamate 8-Me(2) NC(10) H(6) Te(S(2) CNEt(2) ) with hydrochloric acid. The base hydrolysis of 2 provided the novel telluroxanes (8-Me(2) NC(10) H(6) Te)(2) OCl(4) (3), (8-Me(2) NC(10) H(6) Te)(6) O(5) Cl(8) (4), (8-Me(2) NC(10) H(6) Te)(6) O(8) Cl(2) (5), [(8-Me(2) NC(10) H(6) Te)(2) O(3) ](n) (6) and (8-Me(2) NC(10) H(6) Te)(6) O(8) (OH)(2) (7) depending on the reaction conditions applied. The reaction of 7 with ClTe(OiPr)(3) in the presence of water gave rise to the telluroxane (8-Me(2) NC(10) H(6) Te)(6) Te(2) O(12) Cl(2) (8). The crystal and molecular structures of 1-3 and 5-8 were determined by X-ray crystallography. The telluroxane clusters and polymers 6-8 hold potential as model compounds for alkali tellurite glasses (M(2) O)(x) (TeO(2) )(1-x) (M=Li, Na, K) for which no precise structural data are available. PMID:21226110

Beckmann, Jens; Bolsinger, Jens; Duthie, Andrew

2011-01-17

67

Solvent-vapour-assisted pathways and the role of pre-organization in solid-state transformations of coordination polymers  

PubMed Central

A family of one-dimensional coordination polymers, [Ag4(O2C(CF2)2CF3)4(phenazine)2(arene)n]·m(arene), 1 (arene = toluene or xylene), have been synthesized and crystallographically characterized. Arene guest loss invokes structural transformations to yield a pair of polymorphic coordination polymers [Ag4(O2C(CF2)2CF3)4(phenazine)2], 2a and/or 2b, with one- and two-dimensional architectures, respectively. The role of pre-organization of the polymer chains of 1 in the selectivity for formation of either polymorph is explored, and the templating effect of toluene and p-xylene over o-xylene or m-xylene in the formation of arene-containing architecture 1 is also demonstrated. The formation of arene-free phase 2b, not accessible in a phase-pure form through other means, is shown to be the sole product of loss of toluene from 1-tol·tol [Ag4(O2C(CF2)2CF3)4(phenazine)2(toluene)]·2(toluene), a phase containing toluene coordinated to Ag(I) in an unusual ?:?1,?1 manner. Solvent-vapour-assisted conversion between the polymorphic coordination polymers and solvent-vapour influence on the conversion of coordination polymers 1 to 2a and 2b is also explored. The transformations have been examined and confirmed by X-ray diffraction, NMR spectroscopy and thermal analyses, including in situ diffraction studies of some transformations.

Wright, James S.; Vitórica-Yrezábal, Iñigo J.; Adams, Harry; Thompson, Stephen P.; Hill, Adrian H.; Brammer, Lee

2015-01-01

68

Lanthanide-polyphosphonate coordination polymers combining catalytic and photoluminescence properties.  

PubMed

A rapid, mild and high-yield microwave synthesis of 1D isotypical [Ln(H4bmt)(H5bmt)(H2O)2]·3H2O coordination polymers is presented. The La(3+)-based material is highly active as a heterogeneous catalyst in the methanolysis of styrene oxide at nearly room temperature. Eu(3+)- and Tb(3+)-doped materials are very effective UV-to-visible light converters. PMID:23752868

Vilela, Sérgio M F; Firmino, Ana D G; Mendes, Ricardo F; Fernandes, José A; Ananias, Duarte; Valente, Anabela A; Ott, Holger; Carlos, Luís D; Rocha, João; Tomé, João P C; Paz, Filipe A Almeida

2013-07-21

69

Stepwise assembly of a semiconducting coordination polymer [Cd8S(SPh)14(DMF)(bpy)]n and its photodegradation of organic dyes.  

PubMed

Chalcogenolate clusters can be interlinked with organic linkers into semiconducting coordination polymers with photocatalytic properties. Here, discrete clusters of Cd8S(SPh)14(DMF)3 were interlinked with 4,4'-bipyridine into a one dimensional coordination polymer of [Cd8S(SPh)14(DMF)(bpy)]n with helical chains. A stepwise mechanism for the assembly of the coordination polymer in DMF was revealed by an ex situ dynamic light scattering study. The cluster was electrostatically neutral and showed a penta-supertetrahedral structure. During the assembly each cluster was interlinked with two 4,4'-bipyridine molecules, which replaced the two terminal DMF molecules of the clusters. In their solid-state forms, the cluster and the coordination polymer were semiconductors with wide band gaps of 3.08 and 2.80 ev. They photocatalytically degraded rhodamine B and methylene blue in aqueous solutions. The moderate conditions used for the synthesis could allow for further in situ studies of the reaction-assembly of related clusters and coordination polymers. PMID:25747254

Xu, Chao; Hedin, Niklas; Shi, Hua-Tian; Xin, ZhiFeng; Zhang, Qian-Feng

2015-03-24

70

Homochiral coordination polymers constructed from aminocarboxylate derivates: Effect of bipyridine on the amidation reaction  

SciTech Connect

Using aminocarboxylate derivates (S)-N-(4-cyanobenzoic)-glutamic acid (denoted as cbg, 1a) and (S)-N-(4-nitrobenzoic)-glutamic acid (denoted as nbg, 1b) as chiral ligands, five new homochiral coordination polymers formulated as [Cu(cbg)(H{sub 2}O){sub 2}]{sub n} (3), [Cu(cbop){sub 2}(4,4 Prime -bipy)(H{sub 2}O)]{sub n} (4) (cbop=(S)-N-(4-cyanobenzoic)-5-oxoproline, 4,4 Prime -bipy=4,4 Prime -bipyridine), {l_brace}[Cu(nbop){sub 2}(4,4 Prime -bipy)]{center_dot}4H{sub 2}O{r_brace}{sub n} (5) (nbop=(S)-N-(4-nitrobenzoic)-5-oxoproline), {l_brace}[Cd(nbop){sub 2}(4,4 Prime -bipy)]{center_dot}2H{sub 2}O{r_brace}{sub n} (6), and [Ni(nbop){sub 2}(4,4 Prime -bipy)(H{sub 2}O){sub 2}]{sub n} (7) have been hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction study reveals that the original chirality of aminocarboxylate derivates is maintained in all these complexes. Complexes 3, 4, and 7 are one-dimensional infinite chain coordination polymers, while complexes 5 and 6 possess two-dimensional network structures. In situ cyclization of 1a and 1b was taken place in the formation of complexes 4-7, which may be due to the competition of 4,4 Prime -bipyridine with chiral ligands during the coordination process. Preliminary optical behavior investigation indicates that ligands 1a, 1b, and complexes 6, 7 are nonlinear optical active. - Graphical abstract: Using aminocarboxylate derivates as chiral ligands, five new homochiral coordination polymers possessing second harmonic generation activities have been hydrothermally synthesized. Highlights: Black-Right-Pointing-Pointer Two new chiral aminocarboxylate derivates were firstly synthesized. Black-Right-Pointing-Pointer Five new homochiral metal organic complexes were obtained hydrothermally based on these ligands. Black-Right-Pointing-Pointer Intramolecular amidation was taken place on the aminocarboxylate derivates during the formation of these complexes. Black-Right-Pointing-Pointer In situ amidation may be due to the impact of 4,4 Prime -bipyridine. Black-Right-Pointing-Pointer The homochiral complexes are nonlinear optical active.

Chen Jianshan; Sheng Tianlu; Hu Shengmin; Xiang Shengchang; Fu Ruibiao; Zhu Qilong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Wu Xintao, E-mail: wxt@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2012-08-15

71

One-dimensional silicone nanofilaments.  

PubMed

A decade ago one-dimensional silicone nanofilaments (1D-SNF) such as fibres and wires were described for the first time. Since then, the exploration of 1D-SNF has led to remarkable advancements with respect to material science and surface science: one-, two- and three-dimensional nanostructures of silicone were unknown before. The discovery of silicone nanostructures marks a turning point in the research on the silicone material at the nanoscale. Coatings made of 1D-SNF are among the most superhydrophobic surfaces known today. They are free of fluorine, can be applied to a large range of technologically important materials and their properties can be modified chemically. This opens the way to many interesting applications such as water harvesting, superoleophobicity, separation of oil and water, patterned wettability and storage and manipulation of data on a surface. Because of their high surface area, coatings consisting of 1D-SNF are used for protein adsorption experiments and as carrier systems for catalytically active nanoparticles. This paper reviews the current knowledge relating to the broad development of 1D-SNF technologies. Common preparation and coating techniques are presented along with a comparison and discussion of the published coating parameters to provide an insight on how these affect the topography of the 1D-SNF or coating. The proposed mechanisms of growth are presented, and their potentials and shortcomings are discussed. We introduce all explored applications and finally identify future prospects and potentials of 1D-SNF with respect to applications in material science and surface science. PMID:24742356

Artus, Georg R J; Seeger, Stefan

2014-07-01

72

(1-Butyl-4-methyl-pyridinium)[Cu(SCN)2]: a coordination polymer and ionic liquid.  

PubMed

The compound (C4C1py)[Cu(SCN)2], (C4C1py = 1-Butyl-4-methyl-pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic-inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2](-) units, in which the thiocyanates bridge the copper ions in a ?1,3-fashion. The resulting one-dimensional chains run along the a?axis, separated by the C4C1py counterions. Powder X-ray diffraction not only confirms the single-crystal X-ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature-dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100?°C point towards the formation of polyanionic chain fragments in the melt. Solid-state UV/Vis spectroscopy shows a broad absorption band around 18,870?cm(-1) (530?nm) and another strong one below 20,000?cm(-1) (<500?nm). The latter is attributed to the d(Cu(I))??*(SCN)-MLCT (metal-to-ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4?eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15,870?cm(-1) (630?nm) with a quantum efficiency of 0.90(2)?% and a lifetime of 131(2)?ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450?nm in the excitation spectrum decreases. PMID:24644064

Spielberg, Eike T; Edengeiser, Eugen; Mallick, Bert; Havenith, Martina; Mudring, Anja-Verena

2014-04-25

73

A new two-dimensional manganese(II) coordination polymer based on thiophene-3,4-dicarboxylic acid.  

PubMed

A novel manganese coordination polymer, poly[(?5-thiophene-3,4-dicarboxylato)manganese(II)], [Mn(C6H2O4S)]n, was synthesized hydrothermally using 3,4-thiophenedicarboxylate (3,4-tdc(2-)) as the organic linker. The asymmetric unit of the complex contains an Mn(2+) cation and one half of a deprotonated 3,4-tdc(2-) anion, both residing on a twofold axis. Each Mn(2+) centre is six-coordinated by O atoms of bridging/chelating carboxylate groups from five 3,4-tdc(2-) anions, forming a slightly distorted octahedron. The Mn(2+) centres are bridged by 3,4-tdc(2-) anions to give an infinite two-dimensional layer which incorporates one-dimensional Mn-O gridlike chains, and in which the 3,4-tdc(2-) anion adopts a novel hexadentate chelating and ?5-bridging coordination mode. The fully deprotonated 3,4-tdc(2-) anion exhibits unexpected efficiency as a ligand towards the Mn(2+) centres, which it coordinates through all of its carboxylate O atoms to provide the novel coordination mode. The IR spectrum of the complex is also reported. PMID:24992118

Wang, Gui-Xia; Shang, Li-Li; Li, Zhao-Hao; Zhao, Bang-Tun

2014-07-01

74

One- and two-dimensional Cd(II) coordination polymers incorporating organophosphinate ligands.  

PubMed

Reaction of cadmium nitrate with diphenylphosphinic acid in dimethylformamide solvent yielded the one-dimensional coordination polymer catena-poly[[bis(dimethylformamide-?O)cadmium(II)]-bis(?-diphenylphosphinato-?(2)O:O')], [Cd(C12H10O2P)2(C3H7NO)2]n, (I). Addition of 4,4'-bipyridine to the synthesis afforded a two-dimensional extended structure, poly[[(?-4,4'-bipyridine-?(2)N:N')bis(?-diphenylphosphinato-?(2)O:O')cadmium(II)] dimethylformamide monosolvate], {[Cd(C12H10O2P)2(C10H8N2)]·C3H7NO}n, (II). In (II), the 4,4'-bipyridine molecules link the Cd(II) centers in the crystallographic a direction, while the phosphinate ligands link the Cd(II) centers in the crystallographic b direction to complete a two-dimensional sheet structure. Consideration of additional ?-? interactions of the phenyl rings in (II) produces a three-dimensional structure with channels that encapsulate dimethylformamide molecules as solvent of crystallization. Both compounds were characterized by single-crystal X-ray diffraction and FT-IR analysis. PMID:25370109

Rood, Jeffrey A; Boyer, Steven; Oliver, Allen G

2014-11-01

75

New 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers  

SciTech Connect

The hydrothermal self-assemblies of Pb{sup 2+}/Cd{sup 2+} salt, 4,5-dichlorophthalic acid (dcpha), N{sub 2}H{sub 4}.H{sub 2}O together with 1,10-phenanthroline.H{sub 2}O (phen) or 2,2'-bipyridine (bpy) generated two new monoacylhydrazidate-bridged 1-D chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2 (DCPTH=4,5-dichlorophthalhydrazidate, dcph=4,5-dichlorophthalate). The monoacylhydrazidate ligand DCPTH originated from the hydrothermal in situ acylation reaction between dcpha and N{sub 2}H{sub 4}.H{sub 2}O. In compound 1, two types of coordination modes for DCPTH are found, which link alternately the Pb(II) centers into a 1-D chain structure of compound 1 with ancillary phen molecules. In compound 2, DCPTH and dcph as the mixed bridges extend the Cd(II) centers into a 1-D chain structure of compound 2 with auxiliary bpy molecules. DCPTH in compound 2 shows a different coordination mode from those observed in compound 1. -- Graphical abstract: By applying the in situ acylation reaction between 4,5-diclorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O, two 4,5-dichlorophthalhydrazidate-bridged chained compounds [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] (4,5-dichlorophthalhydrazidate=DCPTH, and dcph=4,5-dichlorophthalate) were hydrothermally synthesized. Display Omitted Research highlights: > In this article, we first reported the preparations and structural characterization of two examples of 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2. 4,5-dichlorophthalhydrazidate derived from the hydrothermal in situ acylation reactions between 4,5-dichlorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O. > In this article, a simple method to judge whether the polycarboxylic acid precursors have acylated into the acylhydrazidate ligands is introduced. > In this article, DFT calculations were carried out on the excited electronic states of the compounds, the fluorescence emission properties of the compounds have been better understood. > this article, by the structural characterization of the obtained monoacylhydrazidate-containing compounds, the character of the monoacylhydrazidate ligands has been further understood.

Jin, Juan [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Wu, Di [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023 (China); Jia, Ming-Jun [Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Qianjin Road 2699, Changchun 130012 (China); Peng, Yu [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Yu, Jie-Hui, E-mail: jiehuiyu@yahoo.com.c [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, Jiangsu 210093 (China); Wang, Yu-Chang [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Xu, Ji-Qing, E-mail: xjq@mail.jlu.edu.c [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China)

2011-03-15

76

Determining the coordinate dependence of some components of the cubic susceptibility tensor {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}) of a one-dimensionally inhomogeneous absorbing plate at an arbitrary frequency dispersion  

SciTech Connect

The possibility of unique reconstruction of the spatial profile of the cubic nonlinear susceptibility tensor component {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}) of a one-dimensionally inhomogeneous plate whose medium has a symmetry plane m{sub y} perpendicular to its surface is proved for the first time and the unique reconstruction algorithm is proposed. The amplitude complex coefficients of reflection and transmission (measured in some range of angles of incidence) as well as of conversion of an s-polarised plane signal monochromatic wave into two waves propagating on both sides of the plate make it possible to reconstruct the profile. These two waves result from nonlinear interaction of a signal wave with an intense plane wave incident normally on the plate. All the waves under consideration have the same frequency {omega}, and so its variation helps study the frequency dispersion of the cubic nonlinear susceptibility tensor component {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}). For media with additional symmetry axes 2{sub z}, 4{sub z}, 6{sub z}, or {infinity}{sub z} that are perpendicular to the plate surface, the proposed method can be used to reconstruct the profile and to examine the frequency dispersion of about one third of all independent complex components of the tensor {chi}-hat{sup (3)}. (nonlinear-optics phenomena)

Golubkov, A A [Department of Physics, Advanced Educational and Scientific Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Makarov, Vladimir A [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2010-12-29

77

One-dimensional photonic crystal design  

Microsoft Academic Search

In this article we present a method to determine the band spectrum, band gaps, and discrete energy levels, of a one-dimensional photonic crystal with localized impurities. For one-dimensional crystals with piecewise constant refractive indices we develop an algorithm to recover the refractive index distribution from the period map. Finally, we derive the relationship between the period map and the scattering

Cornelis van der Mee; Pietro Contu; Paolo Pintus

2010-01-01

78

Polymer complexes. LX. Supramolecular coordination and structures of N(4-(acrylamido)-2-hydroxybenzoic acid) polymer complexes.  

PubMed

A number of novel polymer complexes of various anions of copper(II), cobalt(II), nickel(II) and uranyl(II) with N(4-(acrylamido)-2-hydroxy benzoic acid) (ABH) have been synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurements, electronic spin resonance, vibrational spectra and thermal analysis. The molecular structures of the ligand are optimized theoretically and the quantum chemical parameters are calculated. Tentative structures for the polymeric metal complexes due to their potential application are also suggested. The IR data exhibit the coordination of ONO2/OAc/SO4 with the metal ions in the polymeric metal complex. Vibrational spectra indicate coordination of carboxylate oxygen and phenolic OH of the ligand giving a MO4 square planar chromophore. Ligand field ESR spectra support square planar geometry around Cu(II). The thermal decomposition of the polymer complexes were discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coast-Redfern and Horowitz-Metzger methods. PMID:25589393

Ghoneim, M M; El-Sonbati, A Z; El-Bindary, A A; Diab, M A; Serag, L S

2015-04-01

79

Nanoscale coordination polymers for platinum-based anticancer drug delivery.  

PubMed

Pt-containing nanoscale coordination polymer (NCP) particles with the formula of Tb2(DSCP)3(H2O)12 (where DSCP represents disuccinatocisplatin), NCP-1, were precipitated from an aqueous solution of Tb3+ ions and DSCP bridging ligands via the addition of a poor solvent. SEM and TEM images showed that as-synthesized NCP-1 exhibited a spherical morphology with a DLS diameter of 58.3 +/- 11.3 nm. NCP-1 particles were stabilized against rapid dissolution in water by encapsulation in shells of amorphous silica. The resulting silica-coated particles NCP-1' exhibited significantly longer half-lives for DSCP release from the particles (a t1/2 of 9 h for NCP-1' with 7 nm silica coating vs t1/2 of 1 h for as-synthesized NCP-1). In vitro cancer cell cytotoxicity assays with the human colon carcinoma cell line (HT-29) showed that internalized NCP-1' particles readily released the DSCP moieties which were presumably reduced to cytotoxic Pt(II) species to give the Pt-containing NCPs anticancer efficacy superior to the cisplatin standard. The generality of this degradable nanoparticle formulation should allow for the design of NCPs as effective delivery vehicles for a variety of biologically and medically important cargoes such as therapeutic and imaging agents. PMID:18686947

Rieter, William J; Pott, Kimberly M; Taylor, Kathryn M L; Lin, Wenbin

2008-09-01

80

Lanthanide coordination polymers: Synthesis, diverse structure and luminescence properties  

NASA Astrophysics Data System (ADS)

The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis{[(2?-furfurylaminoformyl)phenoxyl]methyl}-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schläfli symbol 63, vertex symbol 6 6 6) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of EuIII, TbIII and DyIII complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in EuIII, TbIII and DyIII complexes can be efficiently sensitized by the ligand.

Song, Xue-Qin; Lei, Yao-Kun; Wang, Xiao-Run; Zhao, Meng-Meng; Peng, Yun-Qiao; Cheng, Guo-Quan

2014-10-01

81

The structural diversity and photoluminescent properties of cadmium thiophenedicarboxylate coordination polymers.  

PubMed

Two series of Cd(II) coordination polymers (CPs), {[Cd(bimm)2(H2O)2][(3,4-tdc)2][H2O]2}n (1a), [Cd(3,4-tdc)(bimb)]n (2a), [Cd(3,4-tdc)(bimpy)(H2O)]n (3a) and [Cd(2,3-Htdc)2(bimm)2]n (1b), {[Cd(2,3-tdc)(bimb)](H2O)}n (2b), [Cd(2,3-tdc)(bimpy)(H2O)]n (3b) where H2tdc = thiophenedicarboxylic acid, bimm = 1,2-bis(imidazol-1'-yl)methane, bimb = 1,2-bis(imidazol-1'-yl)butane and bimpy = 3,5-bis(imidazol-1'-yl)pyridine, have been synthesized by using Cd(II) acetate with H2tdc and N-donor ligands under hydrothermal conditions. Two related isomeric thiophenedicarboxylic acids were chosen to examine the positional isomeric effect on the construction of these CPs with distinct dimensionality and connectivity. The structure of 1a is a one-dimensional (1D) cationic double chain further forming a two-dimensional (2D) supramolecular network via hydrogen-bonding interactions, while 1b exhibits a neutral double chain structure. Interestingly, a three-dimensional (3D) 4-connected cds network for 2a as well as a 1D neutral double chain structure for 2b were obtained in the presence of bimb. When the rigid tripodal bimpy was introduced, isomorphous 3a and 3b with 3D (3,5)-connected (6(2)·8) (6(7)·8(3)) nets were constructed. The structural diversity of 1a-2b mainly stems from the positional isomeric effect of thiophenedicarboxylate, while 3a and 3b are well regulated by rigid bimpy. Moreover, the thermal stability and photoluminescence of 1a-3b are investigated. PMID:24676466

Xue, Li-Ping; Chang, Xin-Hong; Li, Shi-Hui; Ma, Lu-Fang; Wang, Li-Ya

2014-05-21

82

Statistical formulation of one-dimensional electron fluid turbulence  

NASA Technical Reports Server (NTRS)

A one-dimensional electron fluid model is investigated using the mathematical methods of modern fluid turbulence theory. Nondissipative equilibrium canonical distributions are determined in a phase space whose coordinates are the real and imaginary parts of the Fourier coefficients for the field variables. Spectral densities are calculated, yielding a wavenumber electric field energy spectrum proportional to 1/k squared for large wavenumbers. The equations of motion are numerically integrated and the resulting spectra are found to compare well with the theoretical predictions.

Fyfe, D.; Montgomery, D.

1978-01-01

83

One-dimensional gas of hard needles  

E-print Network

We study a one-dimensional gas of needlelike objects as a testing ground for a formalism that relates the thermodynamic properties of “hard” potentials to the probabilities for contacts between particles. Specifically, we ...

Kardar, Mehran

84

One-dimensional staged self-assembly  

E-print Network

We introduce the problem of staged self-assembly of one-dimensional nanostructures, which becomes interesting when the elements are labeled (e.g., representing functional units that must be placed at specific locations). ...

Demaine, Erik D.

85

One-Dimensional Czedli-Type Islands  

ERIC Educational Resources Information Center

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

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

2011-01-01

86

Efficient exhaustive listings of reversible one dimensional  

E-print Network

Efficient exhaustive listings of reversible one dimensional cellular automata Tim Boykett \\Lambda dimensional cellular automata. Using the formulation, certain properties become apparent and connections to combinatorial structures and graph theory become clear. Strong results about uniqueness and isomorphism allows

87

Pose estimation for one-dimensional object with general motion  

NASA Astrophysics Data System (ADS)

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

Liu, Jinbo; Song, Ge; Zhang, Xiaohu

2014-11-01

88

One dimensional representations in quantum optics  

NASA Technical Reports Server (NTRS)

The possibility of representing the quantum states of a harmonic oscillator not on the whole alpha-plane but on its one dimensional manifolds is considered. It is shown that a simple Gaussian distribution along a straight line describes a quadrature squeezed state while a similar Gaussian distribution along a circle leads to the amplitude squeezed state. The connection between the one dimensional representations and the usual Glauber representation is discussed.

Janszky, J.; Adam, P.; Foldesi, I.; Vinogradov, An. V.

1993-01-01

89

Crystal structure, infrared spectra and luminescence of a 1D Cd coordination polymer with 4-nitrophthalic acid and 1,10-phenanthroline monohydrate ligands  

NASA Astrophysics Data System (ADS)

A new one-dimensional (1D) coordination polymer, [Cd(NPTA)(1,10-phen)(H2O)] n ( 1) (H2NPTA = 4-nitrophthalic acid; 1,10-phen = 1,10-phenanthroline monohydrate), has been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction, solid state emission spectra, FT-IR spectra, and thermogravimetric analyses. The compound belongs to triclinic system with space group , and exhibits a one-dimensional linear chain. Each Cd with a strongly distorted octahedral coordination geometry is six-coordinated by two N atoms from one 1,10-phenanthroline ligand, three O atoms from two carboxylate groups of two different NPTA2- ligands and one O atoms from lattice water. Layer supramolecular architecture is formed by medium ?-? stacking interactions between two neighboring phenanthroline rings from two independent linear chains. Studies on luminescent property of 1 exhibit the solid state emission originating from an intra ligand ? ? ?* transition of NPTA2- ligand.

Han, Li-Juan; Kong, Ya-Jie; Sheng, Ning

2015-01-01

90

One-dimensional bimetallic cyano complexes with nicotinamide and isonicotinamide ligands  

NASA Astrophysics Data System (ADS)

Two new 1D bimetallic Cu(II)/Ni(II) coordination polymers, {[Cu(NH3)4(?-na)][Ni(CN)4]}n (1) and {[Cu(NH3)2(ina)2Ni(?-CN)2(CN)2]}n (2) (na: nicotinamide, ina: isonicotinamide) have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, elemental, thermal analyses, and single crystal X-ray diffraction techniques. In both of the complexes, Ni(II) ion is four coordinate with four cyanide-carbon atoms in a square-planar geometry. In 1, the [Ni(CN)4]2- ion acts as a counter-ion, whereas it coordinated to the Cu(II) ions as a bridging ligand in 2. In 1 and 2, each Cu(II) ion is coordinated in a distorted octahedral geometry. Single crystal X-ray analysis showed that 1 and 2 exhibit one-dimensional linear chain running along the crystallographic a-axis and b-axis direction, respectively. Adjacent chains are further stacked through intermolecular hydrogen bonding, NH⋯?, CH⋯Ni and Ni⋯? interactions to form 3D supramolecular network.

Gör, Kansu; Kürkçüo?lu, Güne? Süheyla; Ye?ilel, Okan Zafer; Büyükgüngör, Orhan

2014-02-01

91

Chiral one- and two-dimensional silver(I)-biotin coordination polymers.  

PubMed

Reaction of biotin {C(10)H(16)N(2)O(3)S, HL; systematic name: 5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoic acid} with silver acetate and a few drops of aqueous ammonia leads to the deprotonation of the carboxylic acid group and the formation of a neutral chiral two-dimensional polymer network, poly[[{?(3)-5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}silver(I)] trihydrate], {[Ag(C(10)H(15)N(2)O(3)S)]·3H(2)O}(n) or {[Ag(L)]·3H(2)O}(n), (I). Here, the Ag(I) cations are pentacoordinate, coordinated by four biotin anions via two S atoms and a ureido O atom, and by two carboxylate O atoms of the same molecule. The reaction of biotin with silver salts of potentially coordinating anions, viz. nitrate and perchlorate, leads to the formation of the chiral one-dimensional coordination polymers catena-poly[[bis[nitratosilver(I)]-bis{?(3)-5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}] monohydrate], {[Ag(2)(NO(3))(2)(C(10)H(16)N(2)O(3)S)(2)]·H(2)O}(n) or {[Ag(2)(NO(3))(2)(HL)(2)]·H(2)O}(n), (II), and catena-poly[bis[perchloratosilver(I)]-bis{?(3)-5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}], [Ag(2)(ClO(4))(2)(C(10)H(16)N(2)O(3)S)(2)](n) or [Ag(2)(ClO(4))(2)(HL)(2)](n), (III), respectively. In (II), the Ag(I) cations are again pentacoordinated by three biotin molecules via two S atoms and a ureido O atom, and by two O atoms of a nitrate anion. In (I), (II) and (III), the Ag(I) cations are bridged by an S atom and are coordinated by the ureido O atom and the O atoms of the anions. The reaction of biotin with silver salts of noncoordinating anions, viz. hexafluoridophosphate (PF(6)(-)) and hexafluoridoantimonate (SbF(6)(-)), gave the chiral double-stranded helical structures catena-poly[[silver(I)-bis{?(2)-5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}] hexafluoridophosphate], {[Ag(C(10)H(16)N(2)O(3)S)(2)](PF(6))}(n) or {[Ag(HL)(2)](PF(6))}(n), (IV), and catena-poly[[[{5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}silver(I)]-?(2)-{5-[(3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanoato}] hexafluoridoantimonate], {[Ag(C(10)H(16)N(2)O(3)S)(2)](SbF(6))}(n) or {[Ag(HL)(2)](SbF(6))}(n), (V), respectively. In (IV), the Ag(I) cations have a tetrahedral coordination environment, coordinated by four biotin molecules via two S atoms, and by two carboxy O atoms of two different molecules. In (V), however, the Ag(I) cations have a trigonal coordination environment, coordinated by three biotin molecules via two S atoms and one carboxy O atom. In (IV) and (V), neither the ureido O atom nor the F atoms of the anion are involved in coordination. Hence, the coordination environment of the Ag(I) cations varies from AgS(2)O trigonal to AgS(2)O(2) tetrahedral to AgS(2)O(3) square-pyramidal. The conformation of the valeric acid side chain varies from extended to twisted and this, together with the various anions present, has an influence on the solid-state structures of the resulting compounds. The various O-H···O and N-H···O hydrogen bonds present result in the formation of chiral two- and three-dimensional networks, which are further stabilized by C-H···X (X = O, F, S) interactions, and by N-H···F interactions for (IV) and (V). Biotin itself has a twisted valeric acid side chain which is involved in an intramolecular C-H···S hydrogen bond. The tetrahydrothiophene ring has an envelope conformation with the S atom as the flap. It is displaced from the mean plane of the four C atoms (plane B) by 0.8789 (6) Å, towards the ureido ring (plane A). Planes A and B are inclined to one another by 58.89 (14)°. In the crystal, molecules are linked via O-H···O and N-H···O hydrogen bonds, enclosing R(2)(2)(8) loops, forming zigzag chains propagating along [001]. These chains are linked via N-H···O hydrogen bonds, and C-H···S and C-H···O interactions forming a three-dimensional network. The absolute configurations of biotin and complexes (I), (II), (IV) and

Altaf, Muhammad; Stoeckli-Evans, Helen

2013-02-01

92

Observing solitons in one dimensional magnetic systems  

SciTech Connect

Classical models of one dimensional magnetic systems show that in addition to the linear spin wave excitations, there should exist localized, large amplitude excitations, that can move along the chains while retaining their integrity. It is expected that these excitations, solitons, exist in real materials. The progress that has been made to date in observing solitons in one dimensional magnets by means of neutron scattering, and the difficulties that still remain in unambiguously identifying the soliton contributions to S(q,..omega..) are discussed.

Reiter, G.

1981-01-01

93

New Coordination Polymers Based on Transition Metal Squarates and Pyrazine Ligands  

Microsoft Academic Search

Three new coordination polymers have been prepared by hydrothermal reaction of squaric acid, pyrazine and the metal halides FeCl2· 4H 2O, CoBr2 and NiBr2. In their crystal structures the metal atoms are coordinated by four water molecules and two pyrazine ligands within slightly distorted octahedra. The pyrazine ligands connect the metal atoms via µ-N,N'-coordination to linear chains which are connected

Christian Näther; Jan Greve

2003-01-01

94

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

SciTech Connect

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

He, Xiao [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States) [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States); State Key Laboratory of Precision Spectroscopy and Department of Physics, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062 (China); Ryu, Shinsei [Department of Physics, University of Illinois at Urbana-Champaign, 1100 West Green Street, Urbana, Illinois 61801 (United States)] [Department of Physics, University of Illinois at Urbana-Champaign, 1100 West Green Street, Urbana, Illinois 61801 (United States); Hirata, So, E-mail: sohirata@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States) [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 (United States); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan)

2014-01-14

95

A mixed valent heterometallic Cu(II)/Na(I) coordination polymer with sodium-phenyl bonds.  

PubMed

A mixed valent heterometallic Cu(II)/Na(I) coordination polymer (1) is generated by the reaction of a Schiff base ligand, (6,6'-(1E,1'E)-(2-hydroxypropane-1,3-diyl)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(2-methoxyphenol)) with copper(II) acetate and sodium perchlorate. In addition to the presence of alcohol oxygen-sodium coordination bonds, the single crystal X-ray structure reveals that the 1D coordination polymer is stabilised by the formation of phenyl-sodium ?2-bonds, face-to-face ?-? contacts and Cu-? interactions. PMID:24549373

Datta, Amitabha; Das, Kuheli; Massera, Chiara; Clegg, Jack K; Sinha, Chittaranjan; Huang, Jui-Hsien; Garribba, Eugenio

2014-04-14

96

One-Dimensional Oscillator in a Box  

ERIC Educational Resources Information Center

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

Amore, Paolo; Fernandez, Francisco M.

2010-01-01

97

One-dimensional bigyrotropic magnetic photonic crystals  

Microsoft Academic Search

Electromagnetic wave propagation in a one-dimensional magnetic photonic crystal (MPC) made of bigyrotropic magnetic yttrium-iron garnet and nonmagnetic gadolinium-gallium garnet is theoretically investigated using the 4×4 transfer matrix method. Band gaps in the electromagnetic spectrum are numerically obtained and appear to depend on the helicity and direction of light propagation through the MPC.

I. L. Lyubchanskii; N. N. Dadoenkova; M. I. Lyubchanskii; E. A. Shapovalov; A. Lakhtakia; T. H. M. Rasing

2004-01-01

98

The One-Dimensional Wave Equation  

NSDL National Science Digital Library

Created by Lang Moore for the Connected Curriculum Project, the purpose of this module is to study solutions of initial/boundary value problems for the one-dimensional wave equation. This is one of a much larger set of learning modules hosted by Duke University.

Moore, Lang

99

A statistical formulation of one-dimensional electron fluid turbulence  

NASA Technical Reports Server (NTRS)

A one-dimensional electron fluid model is investigated using the mathematical methods of modern fluid turbulence theory. Non-dissipative equilibrium canonical distributions are determined in a phase space whose co-ordinates are the real and imaginary parts of the Fourier coefficients for the field variables. Spectral densities are calculated, yielding a wavenumber electric field energy spectrum proportional to k to the negative second power for large wavenumbers. The equations of motion are numerically integrated and the resulting spectra are found to compare well with the theoretical predictions.

Fyfe, D.; Montgomery, D.

1977-01-01

100

Crossover from reptation to Rouse dynamics in a one-dimensional model  

NASA Astrophysics Data System (ADS)

A simple one-dimensional model is constructed for polymer motion. It exhibits the crossover from reptation to Rouse dynamics through gradually allowing hernia creation and annihilation. The model is treated by the density matrix technique which permits an accurate finite-size-scaling analysis of the behavior of long polymers.

Drzewi?ski, Andrzej; van Leeuwen, J. M. J.

2006-06-01

101

Synthesis, structure and DFT study of a chelidamic acid based Cu coordination polymer: On the importance of ?-? interactions and hexameric water clusters  

NASA Astrophysics Data System (ADS)

One-dimensional coordination polymer, i.e., {(Hampy)[Cu(chel)(H2O)]?2H2O}n (1, ampy = 2-amino-6-methylpyridine, H3chel = chelidamic acid), has been synthesized and characterized by elemental analysis, IR spectroscopy, solution studies and X-ray single-crystal diffraction. In the monomeric unit of compound 1 the metal center exhibits a distorted square-pyramidal coordination sphere. The Cu(II) ion is coordinated to chelidamic acid and water. These monomers are interlinked generating a 1D polymer by means of the para hydroxyl group of the ligand. Protonated 2-amino-6-methylpyridine rings act as counter cations. The crystal lattice is aggregated through intermolecular interactions, such as electrostatic attraction, N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonding and aromatic ? stacking interactions. Hydrogen bond interactions between the water molecules led to formation of six-membered rings with chair conformation. These assemblies are described and analyzed by means of density functional theory (DFT) calculations since they play an important role in the construction of three-dimensional supramolecular frameworks.

Mirzaei, Masoud; Eshtiagh-Hosseini, Hossein; Karrabi, Zahra; Notash, Behrouz; Bauzá, Antonio; Frontera, Antonio

2015-01-01

102

Synthesis, structure, magnetic properties and EPR spectroscopy of a copper(II) coordination polymer with a ditopic hydrazone ligand and acetate bridges.  

PubMed

A new one dimensional coordination polymer of copper(II), [Cu4(L)2(?2-1,1-OAc)2(?2-1,3-OAc)4]n (1), has been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis [HL = (E)-N'-(phenyl(pyridin-2-yl)methylene)isonicotinhydrazide, OAc = acetate anion]. The coordination polymer contains two kinds of Cu(II) dimers which are connected by two types of acetate (?2-1,1- and ?2-1,3-) bridging groups. The ditopic isonicotinhydrazone ligand coordinates to the Cu1 center through the N2O-donor set and connects to the Cu2 center by a pyridine group of the isonicotine part. The EPR and magnetic susceptibility measurements confirm the existence of two kinds of Cu(II) dimers. The intradimer isotropic exchange was estimated to be +0.80(1) cm(-1) for the ferromagnetic Cu1···Cu1 dimeric unit and -315 (1) cm(-1) for the antiferromagnetic Cu2···Cu2 dimeric unit. PMID:25474021

Bikas, Rahman; Aleshkevych, Pavlo; Hosseini-Monfared, Hassan; Sanchiz, Joaquín; Szymczak, Ritta; Lis, Tadeusz

2015-01-28

103

One-dimensional zeolites as hydrocarbon traps  

Microsoft Academic Search

Several zeolites with varying pore dimensionality have been investigated as hydrocarbon (HC) traps by studying the temperature programmed desorption of propane and toluene mixtures. In one-dimensional (1-D) zeolites, the diffusive motion of propane is blocked by the more-strongly adsorbed toluene thus raising the desorption temperature of propane above its single-component desorption temperature. In the 1-D zeolite EUO, propane is trapped

Kenneth F Czaplewski; Thomas L Reitz; Yoo Joong Kim; Randall Q Snurr

2002-01-01

104

Diffraction from quasi-one-dimensional crystals  

SciTech Connect

General expressions of diffraction intensity distribution of quasi-one-dimensional crystals are evaluated within kinematical approximation. In order to gain the generality, diffraction intensity has been derived for each of the fifteen conformation classes. Characteristic features of the diffraction patterns are discussed and it is shown how the symmetry can be fully determined from the diffraction intensity distribution. General results are tabulated and their application is illustrated on the (10,10) molybdenum disulfide nanotube.

Vukovic, T.; Milosevic, I.; Damnjanovic, M. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia)

2009-04-15

105

One-pot syntheses, coordination, and characterization of application-specific biodegradable ligand-polymers.  

PubMed

Syntheses and chelation of tailored biodegradable polymers to rhenium for medicinal applications are described. A group of bifunctional ligand-initiators consisting of a chelating end for metal complexation and a hydroxyl end suitable to initiate polymerization was utilized in the ring-opening polymerization of l-lactide. The resulting biodegradable ligand-polymers were equipped with a tridentate donor set to coordinate specific metal ions. All synthesized compounds were characterized by IR spectroscopy, 1D/2D NMR spectroscopy and MALDI-TOF mass spectrometry, confirming successful polymerization and coordination to the [Re(CO)(3)](+) core. The pliability of designing application-specific polymers with respect to the nature of the metal ion facilitates extending the application of these biodegradable polymers to early detection of diseases (imaging) and radiotherapy of cancers. PMID:17909655

Saatchi, Katayoun; Häfeli, Urs O

2007-10-21

106

Functionalized lanthanide coordination polymer nanoparticles for selective sensing of hydrogen peroxide in biological fluids.  

PubMed

Lanthanide coordination polymers have recently emerged as very fascinating sensing materials due to their tunable structures and unique optical properties. However, a major problem concerning the applications of lanthanide coordination polymers for fluorescent sensing is their unselective recognition to analytes. In this work, a direct post-modification strategy was employed to prepare functionalized lanthanide coordination polymer nanoparticles (Phe/Tb-CPBA CPNPs) with specific response ability to hydrogen peroxide (H2O2) by using phenylalanine (Phe) as bridging ligands, terbium ions (Tb(3+)) as metal nodes and carboxyphenylboronic acids (CPBAs) as guest ligands. Phe/Tb-CPBA CPNPs emit a strong green fluorescence due to the removal of coordinated water molecules and the sensitization effect of CPBA. Upon the addition of H2O2, however, the quenched fluorescence of Phe/Tb-CPBA CPNPs can be observed owing to an intramolecular charge transfer effect. This finding led to a method for the quantitation of H2O2 in the 6 ?M to 1 mM concentration range and with a detection limit at 2 ?M. Because of the chemoselective H2O2-mediated oxidative deboronation, Phe/Tb-CPBA CPNPs as fluorescent sensors exhibit excellent selectivity to H2O2. Furthermore, Phe/Tb-CPBA CPNPs were successfully used to measure the level of H2O2 in urine samples and showed satisfactory results. We envision that the presented strategy could be extended to design other functionalized coordination polymers with desired functions for various biomedical applications. PMID:25195570

Tan, Hongliang; Ma, Chanjiao; Li, Qian; Wang, Li; Xu, Fugang; Chen, Shouhui; Song, Yonghai

2014-11-01

107

Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.  

PubMed

A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with ?-cyclodextrin (?-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified ?-CD as chain transfer agent. The end group of ?-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of ?-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes. PMID:24828951

Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing; Tang, Ben Zhong

2014-06-01

108

Three new homochiral coordination polymers involving two three-dimensional structural architectures: Syntheses, structures and magnetic properties  

SciTech Connect

The preparations and properties of three new homochiral three-dimensional (3D) coordination polymers, [M(D-cam)(pyz)(H{sub 2}O){sub 2}]{sub n} (M=Co (1) and Ni (2); D-H{sub 2}cam=(+) D-camphoric acid; pyz=pyrazine) and [Mn{sub 2}(D-cam){sub 2}(H{sub 2}O){sub 2}] (3), under solvothermal conditions is described. Single-crystal X-ray diffraction analyses revealed that all of compounds are homochiral 3D structure. 1 and 2 are isostructural and crystallize in the trigonal space group P3{sub 2}21, while 3 crystallizes in monoclinic space group P2{sub 1}. The structure of 1 and 2 consists of metal-D-cam helical chains which are pillared with pyrazine ligands into a 3D framework structure and 3 features a 3D homochiral framework involving one-dimensional manganese-carboxylate chains that are aligned parallel to the b axis. Magnetic susceptibility data of all compounds were collected. The findings indicate that ?{sub 2}-pyrazine dominate weak antiferromagnetic coupling within 1 and 2, while 3 exhibits antiferromagnetic behavior through the carboxylate groups of D-cam ligand. -- Graphical abstract: The preparations and properties of three new homochiral three-dimensional (3D) coordination polymers, [M(D-cam)(pyz)(H{sub 2}O){sub 2}]{sub n} (M=Co (1) and Ni (2); D-H{sub 2}cam=(+) D-camphoric acid; pyz=pyrazine) and [Mn{sub 2}(D-cam){sub 2}(H{sub 2}O){sub 2}] (3), under solvothermal conditions is described. Single-crystal X-ray diffraction analyses revealed that all of compounds are homochiral 3D structure. 1 and 2 are isostructural and crystallize in the trigonal space group P3{sub 2}21, while 3 crystallizes in monoclinic space group P2{sub 1}. The structure of 1 and 2 consists of metal-D-cam helical chains which are pillared with pyrazine ligands into a 3D framework structure and 3 features a 3D homochiral framework involving one-dimensional manganese-carboxylate chains that are aligned parallel to the b axis. Magnetic susceptibility data of all compounds were collected. The findings indicate that ?{sub 2}-pyrazine dominate weak antiferromagnetic coupling within 1 and 2, while 3 exhibits antiferromagnetic behavior through the carboxylate groups of D-cam ligand. Highlights: • Three homochiral 3D coordination polymers were synthesized. • 1 and 2 are 3D structure with metal-D-cam helical chains pillared by pyrazine. • 3 shows a 3D homochiral framework involving 1D manganese-carboxylate chains. • Magnetic data analysis indicates that 1–3 exhibit weak antiferromagnetic coupling.

Chao, Tzu-Ling; Yang, Chen-I., E-mail: ciyang@thu.edu.tw

2014-03-15

109

One dimensional electromagnetic waves on flat surfaces  

NASA Astrophysics Data System (ADS)

We show that one-dimensional electromagnetic waves can be constrained to propagate along a join between two thin sheets when one surface supports transverse magnetic polarized surface waves and the other supports transverse electric polarized surface waves. We calculate the dispersion relation of these modes and show that they are exceptionally tightly confined to the join, with characteristic decay lengths an order of magnitude smaller than the surface waves supported by each individual surface. We give an example of a metasurface implementation where low frequency instances of such waves may be observed.

Horsley, S. A. R.; Hooper, I. R.

2014-10-01

110

Point interactions in acoustics: one dimensional models  

E-print Network

A one dimensional system made up of a compressible fluid and several mechanical oscillators, coupled to the acoustic field in the fluid, is analyzed for different settings of the oscillators array. The dynamical models are formulated in terms of singular perturbations of the decoupled dynamics of the acoustic field and the mechanical oscillators. Detailed spectral properties of the generators of the dynamics are given for each model we consider. In the case of a periodic array of mechanical oscillators it is shown that the energy spectrum presents a band structure.

C. Cacciapuoti; R. Figari; A. Posilicano

2006-07-11

111

Supramolecular polymers with tunable topologies via hierarchical coordination-driven self-assembly and hydrogen bonding interfaces  

PubMed Central

A powerful strategy to obtain complex supramolecular materials is the bottom-up construction of noncovalently bound materials by hierarchical self-assembly. This assembly process involves stepwise, uniform increases to the architectural complexity of a substrate, starting from discrete precursors and growing in dimensionality through controlled reactivity to a final product. Herein, two orthogonal processes are exploited: coordination-driven self-assembly and hydrogen bonding. The former relies on the predictable formation of metal–ligand bonds wherein the directionalities of the rigid precursors used determines the structural outcome. The latter uses 2-ureido-4-pyrimidinone interfaces that are structurally robust by virtue of the quadruple hydrogen bonding that can occur between subunits. By combining these two processes into a single system, it is possible to generate hierarchical materials that preserve the attractive tunability associated with discrete supramolecular coordination complexes. For instance, the synthesis of a one-dimensional chain comprising linked metalla-rhomboids is readily adapted to a 2D cross-linked hexagonal network by simply selecting a different metal acceptor precursor as an assembly component. The specific interactions between subunits, in this case platinum(II)-pyridyl bonds and the quadruple H-bonding of ureidopyrimidinone, are unchanged, establishing a unique strategy to obtain supramolecular polymers with marked topological differences with minimal synthetic redesign. In addition, the structural rigidity imposed by the inclusion of the platinum metallacycles serves to minimize the formation of cyclic oligomers, increasing the efficacy of formation and improving the properties of the resultant materials. Furthermore, this study taps the potential of organoplatinum(II) metallacycles in materials science. PMID:24019475

Yan, Xuzhou; Li, Shijun; Pollock, James Bryant; Cook, Timothy R.; Chen, Jianzhuang; Zhang, Yanyan; Ji, Xiaofan; Yu, Yihua; Huang, Feihe; Stang, Peter J.

2013-01-01

112

Photoluminescence of silver(I) and gold(I) cyanide 1D coordination polymers Craig A. Bayse a,  

E-print Network

Photoluminescence of silver(I) and gold(I) cyanide 1D coordination polymers Craig A. Bayse a Keywords: Time-dependent density functional theory Photoluminescence Coinage metal cyanides a b s t r a c t Silver(I) and gold(I) cyanides exist as 1D coordination polymers and are photoluminescent on the edge

Pike, Robert D.

113

A novel three-dimensional AgI coordination polymer based on mixed naphthalene-1,5-disulfonate and aminoacetate ligands.  

PubMed

The three-dimensional coordination polymer poly[[bis(??-2-aminoacetato)di-?-aqua-??-(naphthalene-1,5-disulfonato)-hexasilver(I)] dihydrate], {[Ag?(C??H?O?S?)(C?H?NO?)?(H?O)?]·2H?O}n, based on mixed naphthalene-1,5-disulfonate (L1) and 2-aminoacetate (L2) ligands, contains two Ag(I) centres (Ag1 and Ag4) in general positions, and another two (Ag2 and Ag3) on inversion centres. Ag1 is five-coordinated by three O atoms from one L1 anion, one L2 anion and one water molecule, one N atom from one L2 anion and one AgI cation in a distorted trigonal-bipyramidal coordination geometry. Ag2 is surrounded by four O atoms from two L2 anions and two water molecules, and two AgI cations in a slightly octahedral coordination geometry. Ag3 is four-coordinated by two O atoms from two L2 anions and two AgI cations in a slightly distorted square geometry, while Ag4 is also four-coordinated by two O atoms from one L1 and one L2 ligand, one N atom from another L2 anion, and one AgI cation, exhibiting a distorted tetrahedral coordination geometry. In the crystal structure, there are two one-dimensional chains nearly perpendicular to one another (interchain angle = 87.0°). The chains are connected by water molecules to give a two-dimensional layer, and the layers are further bridged by L1 anions to generate a novel three-dimensional framework. Moreover, hydrogen-bonding interactions consolidate the network. PMID:23907880

Wu, Hua; Lü, Xiao-Li; Lü, Bo; Dong, Chang-Xun; Wu, Mei-Sheng

2013-08-01

114

A rational route to SCM materials based on a 1-D cobalt selenocyanato coordination polymer.  

PubMed

Thermal annealing of a discrete complex with terminal SeCN anions and monodentate coligands enforces the formation of a 1D cobalt selenocyanato coordination polymer that shows slow relaxation of the magnetization. Therefore, this approach offers a rational route to 1D materials that might show single chain magnetic behaviour. PMID:21617809

Boeckmann, Jan; Näther, Christian

2011-07-01

115

Iron(II) and Copper(I) Coordination Polymers: Electrochromic Materials with and without Chiroptical Properties  

E-print Network

Iron(II) and Copper(I) Coordination Polymers: Electrochromic Materials with and without Chiroptical of deterioration over 150 switching cycles. Additionally, in an effort to assemble an electrochromic device with chiroptical properties, the electrochromism of films generated from the enantiomerically pure CTPCT[FeII CTPCT

Bernhard, Stefan

116

Syntheses, crystal structures and properties of two unusual pillared-layer 3d-4f Ln-Cu heterometallic coordination polymers  

SciTech Connect

Two unusual pillared-layer 3d-4f Ln-Cu heterometallic coordination polymers, {l_brace}[Ln{sub 2}Cu{sub 5}Br{sub 4}(IN){sub 7}(H{sub 2}O){sub 6}].H{sub 2}O{r_brace}{sub n} (Ln=Eu (1) and Gd (2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. The structure determination reveals that 1 and 2 are isostructural and feature a novel three-dimensional pillared-layer hetrometallic structure built upon the linkages of one-dimensional (1D) linear Ln-carboxylate chains, zero-dimensional (0D) Ln-carboxylate Ln{sub 2}(IN){sub 8} dimers, rare 1D zigzag [Cu{sub 5}Br{sub 4}]{sub n} inorganic chains and IN{sup -} pillars. In both 3D structures, there are Ln-carboxylate layers resulted from the connections of 1D Ln-carboxylate chains and 0D Ln{sub 2}(IN){sub 8} dimers through O-H...O hydrogen bondings. The luminescent properties of 1 have been investigated. The magnetic properties of 1 and 2 have also been studied. - Graphical abstract: Two unusual pillared-layer Eu (Gd)-Cu heterometallic coordination polymers have been hydrothermally synthesized. The luminescent properties of Eu-Cu compound and magnetic properties of both compounds are investigated. Highlights: > Two unusual 3D pillared-layer Eu (Gd)-Cu heterometallic coordination polymers have been synthesized. > 1D and 0D Ln-carboxylate motifs construct layers by O-H...O hydrogen bondings. > In both the structures, there are rare 1D zigzag Cu/Br inorganic chains. > Luminescent properties of Eu-Cu compound and magnetic properties of both the compounds are investigated.

Fan Leqing, E-mail: lqfan@hqu.edu.cn [College of Materials Science and Engineering, Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Xiamen, Fujian 361021 (China); Wu Jihuai, E-mail: jhwu@hqu.edu.cn [College of Materials Science and Engineering, Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Xiamen, Fujian 361021 (China); Huang Yunfang [College of Materials Science and Engineering, Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Xiamen, Fujian 361021 (China)

2011-09-15

117

One-Dimensional Photonic Crystal Superprisms  

NASA Technical Reports Server (NTRS)

Theoretical calculations indicate that it should be possible for one-dimensional (1D) photonic crystals (see figure) to exhibit giant dispersions known as the superprism effect. Previously, three-dimensional (3D) photonic crystal superprisms have demonstrated strong wavelength dispersion - about 500 times that of conventional prisms and diffraction gratings. Unlike diffraction gratings, superprisms do not exhibit zero-order transmission or higher-order diffraction, thereby eliminating cross-talk problems. However, the fabrication of these 3D photonic crystals requires complex electron-beam substrate patterning and multilayer thin-film sputtering processes. The proposed 1D superprism is much simpler in structural complexity and, therefore, easier to design and fabricate. Like their 3D counterparts, the 1D superprisms can exhibit giant dispersions over small spectral bands that can be tailored by judicious structure design and tuned by varying incident beam direction. Potential applications include miniature gas-sensing devices.

Ting, David

2005-01-01

118

One-dimensional Vlasov--Maxwell equilibria  

SciTech Connect

The purpose of this paper is to show that the Vlasov equilibrium of a plasma of charged particles in an electromagnetic field is closely related to a fluid equilibrium, where only a few moments of the velocity distribution of the plasma are considered. In this fluid equilibrium the electric field should be calculated from Ohm's law, rather than the Poisson equation. In practice, only one-dimensional equilibria are treated, because the symmetry makes this case tractable. The emphasis here is on gaining a better understanding of the subject, but an alternate way of doing the calculations is suggested. It is shown that particle distributions can be found that are consistent with any reasonable electromagnetic field profile.

Greene, J.M. (General Atomics, San Diego, California 92186-9784 (United States))

1993-06-01

119

Aperiodicity in one-dimensional cellular automata  

SciTech Connect

Cellular automata are a class of mathematical systems characterized by discreteness (in space, time, and state values), determinism, and local interaction. A certain class of one-dimensional, binary site-valued, nearest-neighbor automata is shown to generate infinitely many aperiodic temporal sequences from arbitrary finite initial conditions on an infinite lattice. The class of automaton rules that generate aperiodic temporal sequences are characterized by a particular form of injectivity in their interaction rules. Included are the nontrivial linear'' automaton rules (that is, rules for which the superposition principle holds); certain nonlinear automata that retain injectivity properties similar to those of linear automata; and a wider subset of nonlinear automata whose interaction rules satisfy a weaker form of injectivity together with certain symmetry conditions. A technique is outlined here that maps this last set of automata onto a linear automaton, and thereby establishes the aperiodicity of their temporal sequences. 12 refs., 3 figs.

Jen, E.

1990-01-01

120

Multifunctionality of organometallic quinonoid metal complexes: surface chemistry, coordination polymers, and catalysts.  

PubMed

Quinonoid metal complexes have potential applications in surface chemistry, coordination polymers, and catalysts. Although quinonoid manganese tricarbonyl complexes have been used as secondary building units (SBUs) in the formation of novel metal-organometallic coordination networks and polymers, the potentially wider applications of these versatile linkers have not yet been recognized. In this Account, we focus on these diverse new applications of quinonoid metal complexes, and report on the variety of quinonoid metal complexes that we have synthesized. Through the use of [(?(6)-hydroquinone)Mn(CO)3](+), we are able to modify the surface of Fe3O4 and FePt nanoparticles (NPs). This process occurs either by the replacement of oleylamine with neutral [(?(5)-semiquinone)Mn(CO)3] at the NP surface, or by the binding of anionic [(?(4)-quinone)Mn(CO)3](-) upon further deprotonation of [(?(5)-semiquinone)Mn(CO)3] at the NP surface. We have demonstrated chemistry at the intersection of surface-modified NPs and coordination polymers through the growth of organometallic coordination polymers onto the surface modified Fe3O4 NPs. The resulting magnetic NP/organometallic coordination polymer hybrid material exhibited both the unique superparamagnetic behavior associated with Fe3O4 NPs and the paramagnetism attributable to the metal nodes, depending upon the magnetic range examined. By the use of functionalized [(?(5)-semiquinone)Mn(CO)3] complexes, we attained the formation of an organometallic monolayer on the surface of highly ordered pyrolitic graphite (HOPG). The resulting organometallic monolayer was not simply a random array of manganese atoms on the surface, but rather consisted of an alternating "up and down" spatial arrangement of Mn atoms extending from the HOPG surface due to hydrogen bonding of the quinonoid complexes. We also showed that the topology of metal atoms on the surface could be controlled through the use of quinonoid metal complexes. A quinonoid rhodium complex showed catalytic activity in Suzuki-Miyaura type reaction. As a result of the excellent stability of the homogeneous catalyst [(quinone)Rh(COD)](-) in water, we also successfully demonstrated catalyst recycling in 1,2- and 1,4-addition reactions. The compound [(quinone)Ir(COD)](-) showed significantly poorer catalytic activity in 1,4-addition reactions. Following upon the excellent coordination ability of the quinonoid rhodium complexes to metal centers, we synthesized organometallic coordination polymer nanocatalysts and silica gel-supported quinonoid rhodium catalysts, the latter using a surface sol-gel technique. The resulting heterogeneous catalysts showed activity in the stereospecific polymerization of phenylacetylene. PMID:23745596

Kim, Sang Bok; Pike, Robert D; Sweigart, Dwight A

2013-11-19

121

Variations of structures and solid-state conductivity of isomeric silver(I) coordination polymers having linear and V-shaped thiophene-centered ditriazole ligands  

NASA Astrophysics Data System (ADS)

A pair of new linear and V-shaped acceptor-donor-acceptor (A-D-A) thiophene-centered ditriazole structural isomers, i.e., 2,5-di(1H-1,2,4-triazol-1-yl)thiophene (L1) and 3,4-di(1H-1,2,4-triazol-1-yl)thiophene (L2), has been synthesized and characterized. They are used as ?2-bridging ligands to prepare a pair of silver(I) coordination polymers formulated as [Ag(L1)(NO3)]n (1) and [Ag(L2)(NO3)]n (2), which are also structural isomers at the supramolecular level. X-ray single-crystal diffraction analyses for 1 and 2 reveal that they exhibit the same one-dimensional (1D) coordination polymers but different structural architectures because of the distinguishable shape and configuration of isomeric ligands (L1 and L2) and the alterations of the coordination numbers. More interestingly, compared with the free ligands, 1D silver(I) polymeric isomers 1 and 2 show significant enhancement of solid-state conductivity to different extents (1.42×104 and 2.17×103 times), where 6.96 times' enhancement of solid-state conductivity from 1 to 2 has been observed. The formation of Ag-N coordinative bonds and the configurational discrepancy of L1 and L2 are believed to play important roles in facilitating the electron transport between molecules, which can also be supported by Density Function Theory calculations of their band gaps.

Hu, Bin; Geng, Jiao; Zhang, Lie; Huang, Wei

2014-07-01

122

Synthesis, crystal structures and luminescent properties of two 4d-4f Ln-Ag heterometallic coordination polymers based on anion template  

SciTech Connect

Two new 4d-4f Ln-Ag heterometallic coordination polymers, {l_brace}[Ln{sub 3}Ag{sub 5}(IN){sub 10}(H{sub 2}O){sub 7}].4(ClO{sub 4}).4(H{sub 2}O){r_brace}{sub n} (Ln=Eu (1) and Sm (2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions by reactions of Ln{sub 2}O{sub 3}, AgNO{sub 3}, HIN and HClO{sub 4}, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. It is proved that HClO{sub 4} not only adjusts the pH value of the reaction mixture, but also acts as anion template. The structure determination reveals that 1 and 2 are isostructural and feature a novel two-dimensional (2D) layered hetrometallic structure constructed from one-dimensional Ln-carboxylate chains and pillared Ag(IN){sub 2} units. The 2D layers are further interlinked through Ag...Ag and Ag...O(ClO{sub 4}{sup -}) multiple weak interactions, which form a rare Ag-ClO{sub 4} ribbon in lanthanide-transition metal coordination polymers, to give rise to a three-dimensional supramolecular architecture. Moreover, the luminescent properties of these two compounds have also been investigated at room temperature. -- Graphical abstract: Two new anion-templated 2D 4d-4f Ln-Ag heterometallic coordination polymers based on novel lanthanide-carboxylate chains and pillared Ag(IN){sub 2} units, {l_brace}[Ln{sub 3}Ag{sub 5}(IN){sub 10}(H{sub 2}O){sub 7}].4(ClO{sub 4}).4(H{sub 2}O){r_brace}{sub n} (Ln=Eu (1) and Sm (2), HIN=isonicotinic acid), have been hydrothermally synthesized and structurally characterized. 1 and 2 exhibit good luminescent properties. Display Omitted Research highlights: > Two 2D Eu (Sm)-Ag coordination polymers templated by perchlorate anion have been synthesized. > Polymers consist of novel 1D lanthanide-carboxylate chains. > In both structures, there are rare Ag...Ag and Ag...O(ClO{sub 4}{sup -}) multiple weak interactions. > Both compounds exhibit good luminescent properties.

Fan, Le-Qing, E-mail: lqfan@hqu.edu.c [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Chen, Yuan [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Wu, Ji-Huai, E-mail: jhwu@hqu.edu.c [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Huang, Yun-Fang [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China)

2011-04-15

123

SUSY-inspired one-dimensional transformation optics  

E-print Network

Transformation optics aims to identify artificial materials and structures with desired electromagnetic properties by means of pertinent coordinate transformations. In general, such schemes are meant to appropriately tailor the constitutive parameters of metamaterials in order to control the trajectory of light in two and three dimensions. Here we introduce a new class of one-dimensional optical transformations that exploits the mathematical framework of supersymmetry (SUSY). This systematic approach can be utilized to synthesize photonic configurations with identical reflection and transmission characteristics, down to the phase, for all incident angles, thus rendering them perfectly indistinguishable to an external observer. Along these lines, low-contrast dielectric arrangements can be designed to fully mimic the behavior of a given high-contrast structure that would have been otherwise beyond the reach of available materials and existing fabrication techniques. Similar strategies can also be adopted to replace negative-permittivity domains, thus averting unwanted optical losses.

Mohammad-Ali Miri; Matthias Heinrich; Demetrios N. Christodoulides

2014-08-04

124

SUSY-inspired one-dimensional transformation optics  

E-print Network

Transformation optics aims to identify artificial materials and structures with desired electromagnetic properties by means of pertinent coordinate transformations. In general, such schemes are meant to appropriately tailor the constitutive parameters of metamaterials in order to control the trajectory of light in two and three dimensions. Here we introduce a new class of one-dimensional optical transformations that exploits the mathematical framework of supersymmetry (SUSY). This systematic approach can be utilized to synthesize photonic configurations with identical reflection and transmission characteristics, down to the phase, for all incident angles, thus rendering them perfectly indistinguishable to an external observer. Along these lines, low-contrast dielectric arrangements can be designed to fully mimic the behavior of a given high-contrast structure that would have been otherwise beyond the reach of available materials and existing fabrication techniques. Similar strategies can also be adopted to re...

Miri, Mohammad-Ali; Christodoulides, Demetrios N

2014-01-01

125

Five 8-hydroxyquinolinate-based coordination polymers with tunable structures and photoluminescent properties for sensing nitroaromatics.  

PubMed

Using two 8-hydroxyquinolinate ligands (L1-MOM and L2-MOM) containing 3-pyridyl or 4-pyridyl groups, five novel coordination polymers, namely, [Zn3(L1)6] (1), [Zn(L1)2]·2MeOH (2), [Zn(L2)2] (3), [Cd(L2)2] (4), and [Cd4(L1)6]·13H2O (5), were synthesized and characterized by a variety of techniques. Single-crystal X-ray structures have revealed that these coordination polymers exhibit a structural diversification due to the different choices of metal salts and the effect of pyridyl nitrogen position. Compounds 1-5 exhibited different fluorescence emissions and lifetimes upon excitation in the solid state. The sensing behavior of these polymers was also investigated upon exposure to vapors of various nitroaromatic molecules (analytes). The results show that all five polymers are capable of sensing these nitroaromatic molecules in the vapor phase through fluorescence quenching. Interestingly, 3 exhibits superior sensitivity to the analytes in comparison with other polymers. 2-Nitrotoluene quenches the emission of 3 by as much as 96%. PMID:25367871

Zhang, Liyan; Sun, Liying; Li, Xinyuan; Tian, Yulan; Yuan, Guozan

2015-01-01

126

Novel 3D bismuth-based coordination polymers: Synthesis, structure, and second harmonic generation properties  

SciTech Connect

Two new 3D bismuth containing coordination polymers are reported along with their single crystal structures and SHG properties. Compound 1: Bi{sub 2}O{sub 2}(pydc) (pydc=pyridine-2, 5-dicarboxylate), crystallizes in the monoclinic, polar space group, P2{sub 1} (a=9.6479(9) A, b=4.2349(4) A, c=11.9615(11) A, {beta}=109.587(1) Degree-Sign ), which contains Bi{sub 2}O{sub 2} chains that are connected into a 3D structure via the pydc ligands. Compound 2: Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (1R3S cam=1R3S-camphoric acid) crystallizes in the monoclinic, polar space group, P2{sub 1} (a=19.0855(7) A, b=13.7706(5) A, c=19.2429(7) A, {beta}=90.701(1) Degree-Sign ) and is a true 3D coordination polymer. These are two example of SHG compounds prepared using unsymmetric ligands (compound 1) or chiral ligands (compound 2), together with metals that often exhibit stereochemically-active lone pairs, such as Bi{sup 3+}, a synthetic approach that resulted in polar, non-centrosymmetric, 3D metal-organic coordination polymer. - Graphical Abstract: Structures of two new, polar, 3D Bismuth(III)-based coordination polymers: Bi{sub 2}O{sub 2}(pydc) (compound 1), and Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (compound 2). Highlights: Black-Right-Pointing-Pointer New, polar, 3D Bismuth(III)-based coordination polymers. Black-Right-Pointing-Pointer First polar bismuth-based coordination polymers synthesized via a 'hybrid' strategy. Black-Right-Pointing-Pointer Combination of stereochemically-active lone pairs and unsymmetrical or chiral ligands. Black-Right-Pointing-Pointer Synthesis of class C-SHG materials based on Kurtz-Perry categories.

Wibowo, Arief C.; Smith, Mark D. [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States)] [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States); Yeon, Jeongho; Halasyamani, P. Shiv [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)] [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States); Loye, Hans-Conrad zur, E-mail: zurloye@mail.chem.sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States)

2012-11-15

127

Piezoelectricity and Ferroelectricity in one dimensional nanowires  

NASA Astrophysics Data System (ADS)

Two recent studies, one by Mele and Král on the theoretical study of the polarization and piezoelectricity of BN nanotube and another by Yun et al. on the experimental study of the synthesis and the ferroelectric property of BaTiO3 single crystalline nanowire, showed exciting results for such piezoelectric/ferroelectric nanomaterials being used for studying low dimensional piezoelectricity and ferroelectricity at the nanoscale. These two nanomaterials represent two unique material nanosystems. BN nanotube is layered and uniquely tubular in structure and has chiral symmetry variations; and BaTiO3 nanowire is a crystalline and one dimensional solid. In this study, we report our recent results on the synthesis of BaTiO3 nanowires having diameters of as small as 6 nm, and the piezoelectric characterization of such nanowires; we also present our systematic study of the mechanics and the piezoelectric property of individual BN nanotubes, using our recently developed advanced nanomanipulation tools integrated with various microscopes.

Wang, Zhaoyu; Suryavanshi, Abhijit; Wen, Jianguo; Yu, Min-Feng

2004-03-01

128

Nicotine molecularly imprinted polymer: synergy of coordination and hydrogen bonding.  

PubMed

Two new bis(2,2'-bithienyl)methane derivatives, one with the zinc phthalocyanine substituent (ZnPc-S16) and the other with the 2-hydroxyethyl substituent (EtOH-S4), were synthesized to serve as functional monomers for biomimetic recognition of nicotine (Nic) by molecular imprinting. Formation of a pre-polymerization complex of the Nic template with ZnPc-S16 and EtOH-S4 was confirmed by both the high negative Gibbs free energy gain, ?G = -115.95 kJ/mol, calculated using the density functional theory at the B3LYP/3-21G* level, and the high stability constant, Ks = 4.67 × 10(5) M(-1), determined by UV-vis titration in chloroform. A solution of this complex was used to deposit a Nic-templated molecularly imprinted polymer (MIP-Nic) film on an Au electrode of a quartz crystal resonator of EQCM by potentiodynamic electropolymerization. The imprinting factor was as high as ~9.9. Complexation of the Nic molecules by the MIP cavities was monitored with X-ray photoelectron spectroscopy (XPS), as manifested by a negative shift of the binding energy of the Zn 2p3/2 electron of ZnPc-S16 after Nic templating. For sensing applications, simultaneous chronoamperometry (CA) and piezoelectric microgravimetry (PM) measurements were performed under flow-injection analysis conditions. The limit of detection of the CA and PM chemosensing was as low as 40 and 12 µM, respectively. Among them, the CA chemosensing was more selective to the cotinine and myosmine interferences due to the 1.10 V vs. Ag/AgCl discriminating potential of nicotine electro-oxidation applied. Differences in selectivity to the analyte and interferences were interpreted by modeling complexation of Nic and, separately, each of the interferences with a "frozen" MIP-Nic molecular cavity. PMID:25441415

Huynh, Tan-Phat; B K C, Chandra; Sosnowska, Marta; Sobczak, Janusz W; Nesterov, Vladimir N; D'Souza, Francis; Kutner, Wlodzimierz

2015-02-15

129

Syntheses, structures and photoelectric properties of a series of Cd(II)/Zn(II) coordination polymers and coordination supramolecules  

SciTech Connect

Five Cd(II)/Zn(II) complexes [Cd(1,2-bdc)(pz){sub 2}(H{sub 2}O)]{sub n} (1), [Cd1Cd2(btec)(H{sub 2}O){sub 6}]{sub n} (2), [Cd(3,4-pdc) (H{sub 2}O)]{sub n} (3), [Zn(2,5-pdc)(H{sub 2}O){sub 4}]{center_dot}2H{sub 2}O (4) and {l_brace} [Zn(2,5-pdc)(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace} {sub n} (5) (H{sub 2}bdc=1,2-benzenedicarboxylic acid, pz=pyrazole, H{sub 4}btec=1,2,4,5-benzenetetracarboxylic acid, H{sub 2}pdc=pyridine-dicarboxylic acid) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction, surface photovoltage spectroscopy, XRD, TG analysis, IR and UV-vis spectra and elemental analysis. Structural analyses show that complexes 1-3 are 1D, 2D and 3D Cd(II) coordination polymers, respectively. Complex 4 is a mononuclear Zn(II) complex. Complex 5 is a 3D Zn(II) coordination polymer. The surface photoelectric properties of complexes were investigated by SPS. The results indicate that all complexes exhibit photoelectric responses in the range of 300-600 nm, which reveals that they all possess certain photoelectric conversion properties. By the comparative analyses, it can be found that the species and coordination micro-environment of central metal ion, the species and property of ligands affect the intensity and scope of photoelectric response. - Graphical abstract: Five Cd(II)/Zn(II) complexes have been hydrothermally synthesized and characterized. The photoelectric properties were studied with SPS. The species and coordination micro-environment of central metal ion, the species and property of ligands all affect the photoelectric responses. Highlights: Black-Right-Pointing-Pointer Five Cd/Zn complexes have been synthesized and characterized. Black-Right-Pointing-Pointer The SPS results indicate they possess obvious photoelectric conversion property. Black-Right-Pointing-Pointer The species and coordination environment of central metal ion affect SPS. Black-Right-Pointing-Pointer The species and property of ligands affect SPS. Black-Right-Pointing-Pointer By the energy-band theory and the crystal filed theory, the SPS are analyzed and assigned.

Jin Jing; Han Xiao; Meng Qin; Li Dan; Chi Yuxian [School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Niu Shuyun, E-mail: syniu@sohu.com [School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China)

2013-01-15

130

Virtual high throughput screening confirmed experimentally: porous coordination polymer hydration.  

PubMed

Hydrothermal stability is a pertinent issue to address for many industrial applications where percent levels of water can be present at temperatures ranging from subambient to several hundred degrees. Our objective is to understand relative stabilities of MOF materials through experimental testing combined with molecular modeling. This will enable the ultimate design of materials with improved hydrothermal stability, while maintaining the properties of interest. The tools that we have employed for these studies include quantum mechanical calculations based upon cluster models and combinatorial steaming methods whereby a steam stability map was formulated according to the relative stability of different materials. The experimental steaming method allows for high throughput screening of materials stability over a broad range of steam levels as well as in-depth investigation of structural transformations under more highly resolved conditions, while the cluster model presented here yields the correct trends in hydrothermal stability. Good agreement was observed between predicted relative stabilities of materials by molecular modeling and experimental results. Fundamental information from these studies has provided insight into how metal composition and coordination, chemical functionality of organic linker, framework dimensionality, and interpenetration affect the relative stabilities of PCP materials. This work suggests that the strength of the bond between the metal oxide cluster and the bridging linker is important in determining the hydrothermal stability of the PCP. Although the flexibility of the framework plays a role, it is not as important as the metal-linker bond strength. This demonstration of alignment between experimental and calculated observations has proven the validity of the method, and the insight derived herein insight facilitates direction in designing ideal MOF materials with improved hydrothermal stability for desired applications. PMID:19810730

Low, John J; Benin, Annabelle I; Jakubczak, Paulina; Abrahamian, Jennifer F; Faheem, Syed A; Willis, Richard R

2009-11-01

131

From chromium-chromium quintuple bonds to molecular squares and porous coordination polymers.  

PubMed

Reaction of the quintuply bonded chromium(I) dimer [ApCrCrAp] (Ap = sterically demanding 2-aminopyridinate) with pyrazine yields a chromium(II) complex with a ?(4):?(4) face-on coordinated pyrazine dianion. Reaction with 4,4'-bipyridine, on the other hand, completely cleaves the metal-metal bond, leading to a chromium(II)-based molecular square. XRD and magnetic measurements show ligand radical anions and a ferrimagnetic alignment of alternating metal and ligand magnetic moments. Controlled polymerization of the molecular square with pyrazine yields a porous coordination polymer featuring both reduced and nonreduced linkers. PMID:25384210

Noor, Awal; Sobgwi Tamne, Emmanuel; Oelkers, Benjamin; Bauer, Tobias; Demeshko, Serhiy; Meyer, Franc; Heinemann, Frank W; Kempe, Rhett

2014-12-01

132

Water molecule-enhanced CO{sub 2} insertion in lanthanide coordination polymers  

SciTech Connect

Two new lanthanide coordination polymers H{sub 2}N(CH{sub 3}){sub 2}.[Eu{sup III}{sub 2}(L{sub 1}){sub 3}(L{sub 2})] (1, L{sub 1}=isophthalic acid dianion, L{sub 2}=formic acid anion) and [La{sup III}(2,5-PDC)(L{sub 2})](2, 2,5-PDC=2,5-pyridinedicarboxylate dianion) were synthesized under solvothermal conditions. It is of interest that the formic ligand (L{sub 2}) is not contained in the stating materials, but arises from the water molecule-enhanced CO{sub 2} insertion during the solvothermal process. Both of the two compounds exhibit complicated three dimensional sandwich-like frameworks. - Graphical abstract: Two new lanthanide coordination polymers involving water molecule-enhanced CO{sub 2} insertion resulting in the formation of formic anion and dimethylammonium cation were synthesized under solvothermal conditions.

Luo Liushan; Huang Xiaoyuan; Wang Ning; Wu Hongyan; Chen Wenbin; Feng Zihao; Zhu Huiping; Peng Xiaoling; Li Yongxian; Huang Ling [School of Chemistry and Environment, South China Normal University, Guangzhou (China); Yue Shantang, E-mail: yuesht@scnu.edu.c [School of Chemistry and Environment, South China Normal University, Guangzhou (China); Liu Yingliang [School of Chemistry, Jinan University, Guangzhou (China)

2009-08-15

133

Single-crystal X-ray diffraction studies on structural transformations of porous coordination polymers.  

PubMed

X-Ray single-crystal diffraction has been the most straightforward and important technique in structural determination of crystalline materials for understanding their structure-property relationships. This powerful tool can be used to directly visualize the precise and detailed structural information of porous coordination polymers or metal-organic frameworks at different states, which are unique for their flexible host frameworks compared with conventional adsorbents. With a series of selected recent examples, this review gives a brief overview of single-crystal X-ray diffraction studies and single-crystal to single-crystal transformations of porous coordination polymers under various chemical and physical stimuli such as solvent and gas sorption/desorption/exchange, chemical reaction and temperature change. PMID:24971601

Zhang, Jie-Peng; Liao, Pei-Qin; Zhou, Hao-Long; Lin, Rui-Biao; Chen, Xiao-Ming

2014-08-21

134

One-dimensional nanomaterials: Synthesis and applications  

NASA Astrophysics Data System (ADS)

My research mainly covers three types of one-dimensional (1D) nanomaterials: metal oxide nanowires, transition metal oxide core-shell nanowires and single-walled carbon nanotubes. This new class of nanomaterials has generated significant impact in multiple fields including electronics, medicine, computing and energy. Their peculiar, fascinating properties are promising for unique applications on electronics, spintronics, optical and chemical/biological sensing. This dissertation will summarize my research work on these three 1D nanomaterials and propose some ideas that may lead to further development. Chapter 1 will give a brief introduction of nanotechnology journey and 1D nanomaterials. Chapter 2 and 3 will discuss indium oxide nanowires, as the representative of metal oxide nanwires. More specifically, chapter 2 is focused on the synthesis, material characterization, transport studies and doping control of indium oxide nanowires; Chapter 3 will give a comprehensive review of our systematic studies on molecular memory applications based on molecule/indium oxide nanowire heterostructures. Chapter 4 will introduce another 1D nanomaterial-transition metal oxide (TMO) core-shell nanowires. The discuss will focus on the synthesis of TMO nanowires, material analysis and their electronic properties as a function of temperature and magnetic field. Chapter 5 is dedicated to aligned single-walled carbon nanotubes (SWNTs) on synthesis with rational control of position and orientation, detailed characterization and construction of scaled top-gated transistors. This chapter presents a way to produce the p- and n-type nanotube transistors based on gate voltage polarity control during electrical breakdown. Finally, chapter 6 summarizes the above discussions and proposes some suggestions for future studies.

Lei, Bo

135

A versatile strategy to construct multifunctional metal oxide@cyanometallate-based coordination polymer heterostructures.  

PubMed

We have developed one versatile spatially confined self-assembly strategy to integrate cyanometallate-based coordination polymers with functional metal oxides into well-defined core@shell heterostructures. The structure, composition, size and morphology of the heterostructures could be facilely controlled. The obtained Fe3O4@Prussian blue heterostructure was evaluated as an appealing multifunctional thermal ablation agent exhibiting response to both magnetic field and light irradiation. PMID:25753227

Bu, Fan-Xing; Xu, Li; Zhang, Wei; Jin, Chuan-Yin; Qi, Rui-Juan; Huang, Rong; Jiang, Ji-Sen

2015-03-24

136

Cucurbit[n]uril-based coordination chemistry: from simple coordination complexes to novel poly-dimensional coordination polymers.  

PubMed

Cucurbit[n]urils are a family of molecular container hosts bearing a rigid hydrophobic cavity and two identical carbonyl fringed portals. They have attracted much attention in supramolecular chemistry because of their superior molecular recognition properties in aqueous media. This review highlights the recent advances and challenges in the field of cucurbit[n]uril-based coordination chemistry. It not only presents progress in the knowledge of such macrocyclic compounds, which range from simple to complicated architectures, but also presents new routes of synthesis and their advantages in hybrid porous solids. The concept of structure "inducer" for their structural design to achieve predictable structures and controlled pores is described. The large pore sizes and hydrophobic cavities of these compounds that lead to unprecedented properties and potential applications are also discussed. PMID:24048328

Ni, Xin-Long; Xiao, Xin; Cong, Hang; Liang, Li-Li; Cheng, Kai; Cheng, Xiao-Jie; Ji, Ning-Ning; Zhu, Qian-Jiang; Xue, Sai-Feng; Tao, Zhu

2013-12-21

137

The synthesis, crystal structure and magnetic properties of a one-dimensional terbium(III)-octacyanidomolybdate(V) assembly.  

PubMed

A one-dimensional cyanide-bridged coordination polymer, poly[[aquadi-?-cyanido-?(4)C:N-hexacyanido-?(6)C-(dimethylformamide-?O)bis(3,4,7,8-tetramethyl-1,10-phenanthroline-?(2)N,N')terbium(III)molybdate(V)] 4.5-hydrate], [MoTb(CN)8(C16H16N2)2(C3H7NO)(H2O)]·4.5H2O}n, has been prepared and characterized through IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The compound consists of one-dimensional chains in which cationic [Tb(tmphen)2(DMF)(H2O)](3+) (tmphen is 3,4,7,8-tetramethyl-1,10-phenanthroline) and anionic [Mo(V)(CN)8](3-) units are linked in an alternating fashion through bridging cyanide ligands. Neighbouring chains are connected by three types of hydrogen bonds (O-H···O, O-H···N and C-H···O) and by ?-? interactions to form a three-dimensional supramolecular structure. In addition, magnetic investigations show that ferromagnetic interactions exist in the compound. PMID:25471419

Shen, Hong

2014-12-01

138

1D Zigzag Coordination Polymers of Copper(II) and Nickel(II) with Mixed Ligands Syntheses and Structures  

E-print Network

FULL PAPER 1D Zigzag Coordination Polymers of Copper(II) and Nickel(II) with Mixed Ligands Paik Suh*[a] Keywords: Magnetic properties / N ligands / Polymers / Copper / Nickel / Self assembly,4 -bipy)]n- (ClO4)2n (2), have been synthesized by the self-assembly of a copper(II) complex of 2,2 -bipy

Paik Suh, Myunghyun

139

Design of Coordination Polymer Gels as Stable Catalytic Systems Bengang Xing, Ming-Fai Choi, and Bing Xu*[a  

E-print Network

ligands. Con- formational flexibility of the ligands and slow formation of the coordination poly- mers catalyze the oxidation of benzyl alcohol to benzaldehyde by using their PdII moieties as the catalytic the formation of coordination polymer gels (TMmetallogels) and their enhanced catalytic activity and remarkable

Xing, Bengang

140

Control of Crystal Structure and Magnetism in Copper(II) Fluoride Based Coordination Polymers  

NASA Astrophysics Data System (ADS)

Whereas magnetic copper (II) halide (halide = chloride or bromide) coordination polymers have been frequently studied, the copper(II) fluoride analogs have been much less investigated. This is due in part to synthetic challenges associated with solubility and reactivity. In analogy to cuprates, Cu-F-Cu linkages are expected to provide strong magnetic superexchange. The magnetic structure of such systems can be tuned by choice of ancillary ligand. Herein, we describe the use of various pyridines, diazines, and triazoles that have the ability to define the structural and magnetic dimensionality. Hydrogen bonding to the fluoride ligand provides an additional opportunity for designing molecule-based materials through a `crystal-engineering' approach. Competition for intermolecular interactions frequently enables stimuli responsive behavior, including pressure-induced phase transitions. This will be illustrated for the CuF2(H2O)2(pyrazine) coordination polymer and the five-coordinate CuF2(H2O)2(3-chloropyridine) molecular solid. The use of new synthetic methods, including the use of high pressure, will be described. Subtle changes in reaction conditions leads to significant changes in structural and magnetic properties.

Schlueter, John; Lapidus, Saul; Manson, Jamie

2013-03-01

141

Hierarchical Effect behind the Supramolecular Chirality of Silver(I)-Cysteine Coordination Polymers.  

PubMed

Cysteine is a sulfur-containing amino acid that easily coordinates to soft metal ions and grafts to noble metal surfaces. Recently, chiroptical activity of Ag(+)/cysteine coordination polymers has been widely studied, while, on the other hand, the appearance of a plasmon-enhanced circular dichroic signal (PECD) at the plasmonic spectral region (? > 400 nm) has been observed for AgNPs capped with chiral sulfur-containing amino acids. These two events are both potentially exploited for sensing applications. However, the presence of Ag(+) ions in AgNP colloidal solution deals with the competition of cysteine grafting at the metal NP surface and/or metal ion coordination. Herein we demonstrate that the chiroptical activity observed by adding cysteine to AgNP colloids prepared by pulsed laser ablation in liquids (PLAL) is mainly related to the formation of CD-active Ag(+)/cysteine supramolecular polymers. The strict correlation between supramolecular chirality and hierarchical effects, driven by different chemical environments experienced by cysteine when different titration modalities are used, is pivotal to validate cysteine as a fast and reliable probe to characterize the surface oxidation of AgNPs prepared by pulsed laser ablation in liquids by varying the laser wavelengths. PMID:25781213

Randazzo, Rosalba; Di Mauro, Alessandro; D'Urso, Alessandro; Messina, Gabriele C; Compagnini, Giuseppe; Villari, Valentina; Micali, Norberto; Purrello, Roberto; Fragalà, Maria Elena

2015-04-01

142

New rational approximants for one-dimensional and quasi-one-dimensional Landau-Ginzburg systems  

SciTech Connect

We study in this paper a technique for extrapolating the high-temperature (weak coupling) expansions towards the strong coupling regime inside the critical region of one- and quasi-one-dimensional Landau-Ginzburg models with two degrees of freedom. This includes a bulk type-II superconductor near H/sub c/2. The procedure combines ideas from the Pade rational-approximants algorithm and from the Borel transform. In contrast to other techniques already applied to the problem, the method proposed has been devised to reproduce correctly both the weak coupling expansion and the leading behavior in the strong coupling region. This leads to systems of nonlinear equations which we have solved in a number of cases. The numerical results for the thermal quantities are compared with exact results and with previous results obtained via other techniques.

Ruggeri, G.J.

1981-02-01

143

A new pillared-layer 3D coordination polymer involving in situ generated formate  

NASA Astrophysics Data System (ADS)

A new Cd-based coordination polymer, [Cd(cpt)(HCOO)]n (1), has been synthesized from 1-(4-carboxyphenyl)-1,2,4-triazole) ligand (Hcpt). The structure was characterized through X-ray crystallography, elemental analysis, and IR spectrum. Compound 1 presents a three-dimensional (3D) pillared-layer structure constructed by metal-formate layers and cpt- ligands. Moreover, the unusual formate anions are generated in situ from the decomposition of DMF precursors. The fluorescence property of 1 in solid state was also researched.

Xia, Yu-Pei; Li, Yun-Wu; Li, Da-Cheng; Du, Yu-Chang; Yao, Qing-Xia; Dou, Jian-Min

2015-02-01

144

Lattice architecture effect on the cooperativity of spin transition coordination polymers  

SciTech Connect

We have investigated in the framework of the Ising-like model, by means of Monte Carlo Metropolis method with open boundary condition, the architecture effect on the cooperativity of spin transition coordination polymers. We have analyzed the influence of several physical parameters (size, pressure, and edge effects) on different lattice architectures which were in good agreement with reported experimental data. We show that the cooperativity of a spin crossover system, characterized by the same number of molecules and the same short- and long-range interaction parameters, is progressively enhanced when going from a 1D chain to a 1D ladder type lattice and to a 2D square lattice.

Chiruta, Daniel [Faculty of Electrical Engineering and Computer Science and Advanced Materials and Nanotechnology Laboratory (AMNOL), ?tefan cel Mare University, Suceava 720229 (Romania); GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); LISV, Université de Versailles Saint-Quentin-en-Yvelines, 78140 Velizy (France); Jureschi, Catalin-Maricel; Rotaru, Aurelian, E-mail: jorge.linares@uvsq.fr, E-mail: rotaru@eed.usv.ro [Faculty of Electrical Engineering and Computer Science and Advanced Materials and Nanotechnology Laboratory (AMNOL), ?tefan cel Mare University, Suceava 720229 (Romania); Linares, Jorge, E-mail: jorge.linares@uvsq.fr, E-mail: rotaru@eed.usv.ro [GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); Garcia, Yann [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur, 1, 1348 Louvain-la-Neuve (Belgium)

2014-02-07

145

A new 3D silver(I) coordination polymer with croconate ligand displaying green luminescent  

NASA Astrophysics Data System (ADS)

One new polymer, [Ag4(C5O5)2(H2O)2]n (C5O52- = croconate dianion), has been synthesized and characterized by element analysis, IR, Raman, single-crystal X-ray diffraction, PXRD, and luminescent analysis. X-ray structural analysis revealed that the ligand was de-protonized entirely and offered five oxygen donors taking part in the coordination, and the tetranuclear silver(I) ions showed 4 and 5 coordination geometries respectively. From the space perspective, the presence of 1D chains that are connected into 2D layers, which are further connected into 3D network can be found within the crystal structure by Agsbnd O and weak Ag⋯Ag interactions. The thermal decomposition process consists of the loss of corresponding water molecules below 380 °C and follow-up decomposition of the main structure. Under the excitation of 380 nm light, the complex displayed green luminescent emission at room temperature.

Feng, Sisi; Yang, Hui; Jiang, Xiaojing; Wang, Yuxiang; Zhu, Miaoli

2015-02-01

146

Multi-Symplectic Lagrangian, One-Dimensional Gas Dynamics  

E-print Network

The equations of Lagrangian, ideal, one-dimensional (1D), compressible gas dynamics are written in a multi-symplectic form using the Lagrangian mass coordinate $m$ and time $t$ as independent variables, and in which the Eulerian position of the fluid element $x=x(m,t)$ is one of the dependent variables. This approach differs from the Eulerian, multi-symplectic approach using Clebsch variables. Lagrangian constraints are used to specify equations for $x_m$, $x_t$ and $S_t$ consistent with the Lagrangian map, where $S$ is the entropy of the gas. We require $S_t=0$ corresponding to advection of the entropy $S$ with the flow. We show that the Lagrangian Hamiltonian equations are related to the de Donder-Weyl multi-momentum formulation. The pullback conservation laws and the symplecticity conservation laws are discussed. The pullback conservation laws correspond to invariance of the action with respect to translations in time (energy conservation) and translations in $m$ in Noether's theorem. The conservation law due to $m$-translation invariance gives rise to a novel nonlocal conservation law involving the Clebsch variable $r$ used to impose $\\partial S(m,t)/\\partial t=0$. Translation invariance with respect to $x$ in Noether's theorem is associated with momentum conservation. We obtain the Cartan-Poincar\\'e form for the system, and use it to obtain a closed ideal of two-forms representing the equation system.

G. M. Webb

2015-02-12

147

From a one-dimensional crystal to a one-dimensional liquid: A comprehensive dynamical study of C60 peapods  

NASA Astrophysics Data System (ADS)

We report an inelastic neutron-scattering investigation of the longitudinal acoustic modes of C60 chains confined inside single walled carbon nanotubes. We take advantage of the orientations of the chains within the plane of the pellet sample to isolate their scattering signatures in the (Q,?) space, which we follow as a function of temperature from 260 K up to 1100 K. The results show the progressive evolution of the confined chain from a one-dimensional (1D) crystal to a linear liquid, the transition occurring within a temperature range of ˜150 K centered around 600 K. The comparison of the data obtained on monomer and polymer peapods allows extracting the speed of sound in the monomer crystalline chains (vmono=3.5 km s-1, vpoly/vmono=1.7). We find that the sound velocity is further reduced by half in the liquid state which reveals that the melting is not only due to harmonic additive thermal fluctuations, but that anharmonic terms in the intermolecular potential play an important role at high temperatures.

Bousige, Colin; Rols, Stéphane; Ollivier, Jacques; Schober, Helmut; Fouquet, Peter; Simeoni, Giovanna G.; Agafonov, Viatcheslav; Davydov, Valery; Niimi, Yoshiko; Suenaga, Kazutomo; Kataura, Hiromichi; Launois, Pascale

2013-05-01

148

Bright luminescence in lanthanide coordination polymers with tetrafluoroterephthalate as a bridging ligand.  

PubMed

Ten new coordination polymers of the general compositions [Ln(III)(tfBDC)(NO3)(DMF)2]·DMF with Ln(III) = Eu(3+) (), Gd(3+) (), Tb(3+) (), Ho(3+) (), Tm(3+) (), [Ln(III)(tfBDC)(CH3COO)(FA)3]·3FA with Ln(III) = Sm(3+) (), Eu(3+) () and [Ln(III)(tfBDC)(NO3)(DMSO)2] with Ln(III) = Ho(3+) (), Er(3+) () and Tm(3+) () were synthesized and structurally characterized by X-ray single crystal diffraction (tfBDC(2-) = 2,3,5,6-tetrafluoroterephthalate, DMF = N,N'-dimethylformamide, FA = formamide, DMSO = dimethyl sulfoxide). crystallize in the monoclinic space group C2/c with Z = 8, and in P1[combining macron] with Z = 2 and in Pbca with Z = 8. All crystal structures contain binuclear lanthanide nodes that are connected by 2,3,5,6-tetrafluoroterephthalates (tfBDC(2-)) to form two-dimensional polymeric structural units. Despite this common structural feature the coordination within these binuclear units is quite different in detail, e.g. CN = 9 for and CN = 8 for . The emission spectra of the europium (, ) and terbium () compounds reveal bright red and green emission in the visible region. The resulting high quantum yields of 53% () and 67% () at room temperature show that the replacement of organic ligands with C-H groups by perfluorinated ligands leads to compounds with intense emission, as vibrational quenching is reduced. On the other hand, the influence of the coordinating solvent and additional ligands cannot be neglected, as the replacement of DMF by FA and NO3(-) by CH3COO(-) in leads to a reduced quantum yield of only 10%. Thermoanalytical investigations show that all compounds are stable up to 100-150 °C, before a stepwise release of solvent molecules starts followed by a decomposition of the coordination polymer. PMID:25740408

Sobieray, Miriam; Gode, Jens; Seidel, Christiane; Poß, Marieke; Feldmann, Claus; Ruschewitz, Uwe

2015-03-17

149

1D coordination polymers with polychalcogenides as linkers between metal atoms  

SciTech Connect

The reactions of zinc metal with elemental selenium and selenium/sulfur mixtures in liquid ammonia or methylamine under solvothermal conditions in closed glass ampoules at 50 °C lead within some days specifically to [Zn(NH{sub 3}){sub 2}Se{sub 4}]{sub n} (1), [Zn(MeNH{sub 2}){sub 2}Se{sub 4}]{sub n} (2), [Zn(NH{sub 3}){sub 2}Se{sub 2.23}S{sub 1.77}]{sub n} (3). From MnCl{sub 2}, Rb{sub 2}Se and excess Se in n-butylamine [Mn({sup n}BuNH{sub 2}){sub 4}Se{sub 6}]{sub n} (4) is obtained after prolonged reaction time at ambient temperature. The compounds are sensitive towards air and loss of NH{sub 3} or the amine ligands. The crystal structures were determined by single crystal diffraction at low temperatures. As a common structural feature, all compounds represent 1D coordination polymers with polychalcogenide chains as linkers between the metal atoms and consist of infinite [M–Ch{sub m}–]{sub n} chains (M=Zn, Mn; Ch{sub m}=Se{sub 4}, (S/Se){sub 4}, Se{sub 6}). The Zn central atoms in 1–3 have tetrahedral coordination with two amine ligands, the Mn atoms in 4 have octahedral coordination with four amine ligands and cis position of the two Se atoms. Raman spectra of 1–3 show the stretching mode vibrations of the Ch{sub 4} groups. The observation of S–S, S–Se, and Se–Se vibration bands in the spectrum of 3 indicates the presence of mixed S/Se polyanions. An optical band gap of 1.86(5) eV was determined for 2 by diffuse reflectance spectroscopy. - Graphical abstract: The reaction of Zn and Se in liquid methylamine yields dark red [Zn(NH{sub 2}CH{sub 3})Se{sub 4}], a 1D coordination polymer consisting of helical Zn–Se{sub 4}–Zn– chains. - Highlights: • A series of 1D coordination polymers consisting of metal amine complexes concatenated by polychalcogenide ions is presented. • Syntheses were performed as solvothermal reactions in liquid ammonia, liquid methylamine and n-butylamine. • Crystal structures are dominated by helices [M–Ch{sub m}]{sub n}. • Raman spectra show the presence of mixed S/Se polyanions.

Kysliak, Oleksandr; Beck, Johannes, E-mail: j.beck@uni-bonn.de

2013-07-15

150

Aromatic carboxylate effect on dimensionality of three bis(benzimidazole)-based cobalt(II) coordination polymers: Syntheses, structures and properties  

SciTech Connect

Three new metal-organic coordination polymers [Co(4-bbc){sub 2}(bbbm)] (1), [Co(3,5-pdc)(bbbm)]·2H{sub 2}O (2) and [Co(1,4-ndc)(bbbm)] (3) (4-Hbbc=4-bromobenzoic acid, 3,5-H{sub 2}pdc=3,5-pyridinedicarboxylic acid, 1,4-H{sub 2}ndc=1,4-naphthalenedicarboxylic acid and bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole) were hydrothermally synthesized and structurally characterized. Polymer 1 is a 1D chain formed by the bbbm ligands and Co{sup II} ions. Polymer 2 exhibits a 2D network with a (3·4·5)(3{sup 2}·4·5·6{sup 2}·7{sup 4}) topology. Polymer 3 possesses a 3D three-fold interpenetrating framework. The versatile structures of title polymers indicate that the aromatic carboxylates have an important influence on the dimensionality of 1–3. Moreover, the thermal stability, electrochemical and luminescent properties of 1–3 were investigated. - graphical abstract: Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were hydrothermally synthesized and structurally characterized. The aromatic carboxylates play a key role in the dimensionality of three polymers. The electrochemical and luminescent properties of three polymers were investigated. Display Omitted - Highlights: • Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were obtained. • The aromatic carboxylates have an important influence on the dimensionality of three polymers. • The electrochemical and luminescent properties of three polymers were investigated.

Zhang, Ju-Wen; Gong, Chun-Hua; Hou, Li-Li; Tian, Ai-Xiang; Wang, Xiu-Li, E-mail: wangxiuli@bhu.edu.cn

2013-09-15

151

Distributed feedback lasing from a composite poly(phenylene vinylene)-nanoparticle one-dimensional photonic crystal.  

PubMed

Nanoparticle one-dimensional photonic crystals exhibit intense, broadband reflectivity coupled with a unique mesoporosity. The latter property allows for infiltration of the one-dimensional photonic crystal with functional materials, such as emitting polymers, which in turn can lead to the fabrication of composites whereby the emitter's emission can be modulated by the photon density of states of the photonic crystal. We exploit this interaction in order to produce efficient distributed feedback lasing from a composite poly(phenylene vinylene)-infiltrated nanoparticle one-dimensional photonic crystal. PMID:19842702

Puzzo, Daniel P; Scotognella, Francesco; Zavelani-Rossi, Margherita; Sebastian, Maria; Lough, Alan J; Manners, Ian; Lanzani, Guglielmo; Tubino, Riccardo; Ozin, Geoffrey A

2009-12-01

152

Spectroscopic properties of a series of Co(II) coordination polymers and the influence of Co(II) coordination environment on photoelectric property.  

PubMed

Four Co(II) coordination polymers, [Co(suc)]n 1, [Co(pdc)]n 2, {[Co7(suc)4(OH)6(H2O)3]·8H2O}n 3, {[Co(bdc)(phen)(H2O)]·H2O}n 4 (H2suc=succinic acid, H2pdc=pyridine-3,4-dicarboxylic acid, H2bdc=1,2-benzenedicarboxylic acid, phen=1,10-phenanthroline) were hydrothermally synthesized and characterized by X-ray single-crystal diffraction, surface photovoltage spectroscopy (SPS), electrical conductivity, thermogravimetric analysis (TG), ultraviolet visible and near-infrared absorption spectrum (UV-Vis-NIR), infrared spectrum (IR), and elemental analysis. The structural analyses indicate that the coordination numbers of the Co(II) ions are 4, 5, 6 and 6 for the polymers 1-4, respectively. And polymers 1 and 2 exhibit 3D structure formed by suc(2-) and pdc(2-) anions bridging Co(II) ions, respectively. Polymer 3 exhibits a 2D structure with suc(2-) anions bridging seven-nuclear [Co7(OH)6(H2O)3](3-) unit and polymer 4 is a 1D structure bridged by bdc(2-) anions. The surface photoelectric properties of the cobalt polymers were mainly studied by SPS. The results of SPS reveal that all polymers possess certain photoelectric conversion property in the range of 300-800 nm. The influences of the structure, coordination micro-environment of central metal ion and structural dimensionality on response bands of SPS were discussed. PMID:25280332

Jin, Jing; Gong, Yuanyuan; Li, Lei; Han, Xiao; Meng, Qin; Liu, Yonghua; Niu, Shuyun

2015-02-25

153

MULTIPLICITY FREE SPACES WITH A ONE DIMENSIONAL HUBERT RUBENTHALER  

E-print Network

MULTIPLICITY FREE SPACES WITH A ONE DIMENSIONAL QUOTIENT HUBERT RUBENTHALER Abstract. The multiplicity free spaces with a one dimensional quotient were introduced by Thierry Levasseur in [11]. Recently. Introduction 1 2. Multiplicity free spaces. Basic definitions and properties 2 2.1. Prehomogeneous Vector

Paris-Sud XI, Université de

154

Omnidirectional reflection bands of one-dimensional magnetic photonic crystals  

Microsoft Academic Search

We study the omnidirectional reflection bands (ORBs) of one-dimensional magnetic photonic crystals. We show that the ORB is a general property of a one-dimensional magnetic photonic crystal consisting of two alternating layers with different wave impedance and the same index of refraction from the analytical expressions for the edge frequencies of omnidirectional reflection bands. We also derive the analytical expressions

Chul-Sik Kee; Jae-Eun Kim; Hae Yong Park

2004-01-01

155

Coordinates  

NSDL National Science Digital Library

This introduction to the labeling of points on a plane by their Cartesian coordinates can optionally be extended to coordinates in 3-dimensional space, to plane polar coordinates and to 3-dimensional polar coordinates. Students should learn to use Cartesian coordinates (x,y) for defining the position of a point in two dimensions and to use Cartesian coordinates (x,y,z) in 3-dimensional space and learn to appreciate the two ways of defining the z axis. Students should also become familiar with some of the tools and terms used by surveyors such as theodolite, azimuth, elevation, and zenith. Optional items for students familiar with trigonometry and with the theorem of Pythagoras are polar coordinates (r,f ) on the plane, Converting (r,f) to (x,y) and vice versa, at least for r, and Spherical polar coordinates (r,q, f) in 3-dimensional space.

David Stern

156

Two unusual 12-connected metal–organic coordination polymers with fcu net  

SciTech Connect

Two new three-dimensional 12-connected metal–organic coordination polymers, [Zn{sub 2}(bptc)(H{sub 2}O)]·C{sub 2}H{sub 5}OH·H{sub 2}O (1) and [Cd{sub 4}(bptc){sub 2}(bbi)(H{sub 2}O)]·H{sub 2}O (2) (H4bptc=biphenyl-2,5,2?,5?-tetracarboxylic acid, bbi=1,1?-(1,4-butanediyl)bis(imidazole)), have been solvothermally synthesized and structurally characterized by single crystal X-ray diffraction analyses. All compounds are also characterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses and X-ray powder diffraction (XRD). Topological analysis indicates that both 1 and 2 are 12-connected frameworks with fcu topology, which are based on cuboid cage and rob-like (Cd3) subunit as 12-connected nodes, respectively. Furthermore, the luminescence properties of the two compounds were discussed in detail. - Graphical abstract: Two new compounds with unusual 12-connected fcu topology display intriguing structural feature, as well as luminescence property. Display Omitted - Highlights: • Two new 3D metal–organic coordination polymers based on biphenyl-2,5,2?,5?-tetracarboxylic acid ligand have been synthesized. • Two compounds exhibit rare 12-connected fcu topology. • Photoluminescent property at room temperature has been investigated.

Guo, Sheng-Qi [Institute of Polyoxometalate Chemistry, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071 (China); Tian, Dan; Luo, Yu-Hui [Institute of Polyoxometalate Chemistry, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Chen, Xin [School of Pharmaceutical and Life Sciences, Changzhou University, Changzhou, Jiangsu, 213164 (China); Zhang, Hong, E-mail: zhangh@nenu.edu.cn [Institute of Polyoxometalate Chemistry, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China)

2013-09-15

157

catena-Poly[[[(di-2-pyridylamine-?2N2,N2')copper(II)]-?-benzene-1,3-dicarboxylato-?3O1,O1':O3] monohydrate], a zigzag coordination polymer with strong ?-? interactions.  

PubMed

The novel title coordination polymer, {[Cu(C(8)H(4)O(4))(C(10)H(9)N(3))]·H(2)O}(n), synthesized by the slow-diffusion method, takes the form of one-dimensional zigzag chains built up of Cu(II) cations linked by benzene-1,3-dicarboxylate (ipht) anions. An exceptional characteristic of this structure is that it belongs to a small group of metal-organic polymers where ipht is coordinated as a bridging tridentate ligand with monodentate and chelate coordination of individual carboxylate groups. The Cu(II) cation has a highly distorted square-pyramidal geometry formed by three O atoms from two ipht anions and two N atoms from a di-2-pyridylamine (dipya) ligand. The zigzag chains, which run along the b axis, further construct a three-dimensional metal-organic framework via strong face-to-face ?-? interactions and hydrogen bonds. A solvent water molecule is linked to the different carboxylate groups via hydrogen bonds. Thermogravimetric and differential scanning calorimetric analyses confirm the strong hydrogen bonding. PMID:21727619

Rogan, Jelena; Poleti, Dejan; Karanovi?, Ljiljana

2011-07-01

158

Localized cell stimulation by nitric oxide using a photoactive porous coordination polymer platform  

PubMed Central

Functional cellular substrates for localized cell stimulation by small molecules provide an opportunity to control and monitor cell signalling networks chemically in time and space. However, despite improvements in the controlled delivery of bioactive compounds, the precise localization of gaseous biomolecules at the single-cell level remains challenging. Here we target nitric oxide, a crucial signalling molecule with site-specific and concentration-dependent activities, and we report a synthetic strategy for developing spatiotemporally controllable nitric oxide-releasing platforms based on photoactive porous coordination polymers. By organizing molecules with poor reactivity into polymer structures, we observe increased photoreactivity and adjustable release using light irradiation. We embed photoactive polymer crystals in a biocompatible matrix and achieve precisely controlled nitric oxide delivery at the cellular level via localized two-photon laser activation. The biological relevance of the exogenous nitric oxide produced by this strategy is evidenced by an intracellular change in calcium concentration, mediated by nitric oxide-responsive plasma membrane channel proteins. PMID:24158008

Diring, Stéphane; Wang, Dan Ohtan; Kim, Chiwon; Kondo, Mio; Chen, Yong; Kitagawa, Susumu; Kamei, Ken-ichiro; Furukawa, Shuhei

2013-01-01

159

Silver coordination polymers with tri- and hexacyanoethyl-functionalized macrocyclic ligands.  

PubMed

Tri- and hexa-cyanoethyl functionalized 17- () and 42-membered () macrocyclic compounds were obtained by [1 + 1] (for ) or [2 + 2] (for ) cyclocondensation of the corresponding dialdehyde and diethylenetriamine, followed by hydrogenation by KBH4 and subsequent cyano-functionalization with acrylonitrile. They react with silver nitrate, leading to the formation of [AgL(1)](NO3) () and of the metal-organic coordination polymers [Ag2(NO3)2L(1)]n () and {[Ag2](NO3)2}n (). The complexes were characterized by elemental analysis, (1)H NMR, (13)C NMR, IR spectroscopies, and ESI-MS; moreover, , , and were also characterized by single crystal X-ray diffraction. The metal cation in is pentacoordinated with a N3O2 coordination environment; in , the metal cations display N4O2 octahedral and N2O3 square-pyramid coordination and in they are in square-planar N4 sites. In , the ligand acts as a pentadentate chelator, and in the other two cases, the ligands behave as octadentate chelators in a 1?(3)N:?(2)O,2?N,3?N,4?N (in ) or 1?(3)N,2?(3)N,3?N,4?N fashion (in ). The cyanoethyl strands of the ligands are directly involved in the formation of the 2D frameworks of and , which in the former polymer can be viewed as a net composed of hexametallic 36-membered macrocyclic rings and in the latter generates extra hexametallic 58-membered cyclic sets that form zig-zag layers. The thermal analytical and electrochemical properties of these silver complexes were also studied. PMID:25425360

Ma, Zhen; Shi, Huaduan; Deng, Xiuqiang; Guedes da Silva, M Fátima C; Martins, Luísa M D R S; Pombeiro, Armando J L

2015-01-21

160

Syntheses, structures and luminescent properties of silver(I) coordination polymers based on aminopyrimidyl derivatives and 1,2,3,4-butanetetracarboxylic acid  

NASA Astrophysics Data System (ADS)

Two mixed-ligand silver(I) coordination polymers (CPs) of the formula {[Ag 4(mapym) 2(butca)(H 2O) 4]·2H 2O} n ( 1) and [Ag 4(dmapym) 6(butca)·2H 2O] n ( 2) (mapym = 2-amino-4-methylpyrimidine, dmapym = 2-amino-4,6-dimethylpyrimidine, H 4butca = 1,2,3,4-butanetetracarboxylic acid) were prepared by reactions of Ag 2O and 2-aminopyrimidyl ligands with H 4butca under the ammoniacal condition. Both complexes were characterized by element analysis, IR and X-ray single-crystal diffraction. In 1, a pair of ? 2-mapym ligands bind four Ag(I) ions to form [Ag 4(mapym) 2] subunits which stack into one-dimensional (1D) chains via inter-subunit ?⋯? interaction. The ? 6-? 1:? 2:? 1:? 2-butca ligands extend the 1D chains into a two-dimensional (2D) sheet which can be simplified into a 4 4- sql net. When mapym was replaced by dmapym, we obtained 2 as a 1D chain incorporating ? 6-? 1:? 2:? 1:? 2-butca and ? 1-dmapym ligands. The dimensions of 1- 2 decrease from 2D to 1D mainly due to the steric effect of methyl groups. Additionally, the hydrogen-bonding, ?⋯? and C-H⋯? interactions also direct the self-assembly of supramolecular architectures. The photoluminescence properties of the 1 and 2 were investigated in the solid state at room temperature.

Sun, Di; Zhang, Na; Xu, Qin-Juan; Huang, Rong-Bin; Zheng, Lan-Sun

2010-06-01

161

Isostructural 1D coordination polymers of Zn(II), Cd(II) and Cu(II) with phenylpropynoic acid and DABCO as organic linkers  

NASA Astrophysics Data System (ADS)

Using phenylpropynoic acid (PPA) and 1,4-diazabicyclo[2.2.2]octane (DABCO) as organic spacers, isostructural coordination polymers of Zn(II), Cd(II) and Cu(II) were synthesized by solvothermal method and structurally characterized using single crystal XRD, powder XRD, 13C CP-MAS NMR spectroscopy. Single crystal XRD data revealed four PPA units coordinating with two metal ions forming a paddle wheel secondary building unit (SBU). The paddle wheel units are connected through coordination of DABCO nitrogen to the metal centers from the axial positions leading to the formation of the 1D coordination polymers along the c axis. Intermolecular ? stacking and Csbnd H…? interactions between the adjacent polymer chains convert the 1D coordination polymer into an interesting 3D network with the Csbnd H…? bonds running along the crystallographic a and b axes. Thermal and nitrogen adsorption studies of these coordination polymers are reported.

Saravanakumar, Rajendran; Varghese, Babu; Sankararaman, Sethuraman

2014-11-01

162

Pyridine-2,4-dicarboxylate: a versatile building block for the preparation of functional coordination polymers.  

PubMed

The hydrothermal reaction of the pyridine-2,4-dicarboxylate (2,4-pdc) dianion with various 3d metal(II) cations resulted in the formation of a series of one-, two- and three-dimensional coordination polymers with varied network topologies. 2,4-pdc reacted directly with MnCI2 or FeCl2 in water at 200 degrees C under mild basic conditions to give a dense three-dimensional polymer, [M(2,4-pdc)] (M = Mn, 1a; M = Fe, 1b), which supports a highly-connected three-dimensional magnetic exchange lattice. Both 1a and 1b undergo antiferromagnetic ordering and the latter Fe(II)-containing material exhibited spin-canting behavior below 6.5 K. Reaction of 2,4-pdc with CoCl2 under identical conditions gave an unusual zigzag chain polymer, [Co4(2,4-pdc)4(OH2)10] (2), that has large amounts of coordinated H2O. The magnetism of 2 based on isolated Co(II) dimers was modeled using a modified van Vleck approach. Adjustment of the reaction pH resulted in the formation of additional Co(II)-containing materials with strongly contrasting structures: at lower pH in the presence of oxalic acid, the same reaction components gave a protonated molecular species, [Co(2,4-pdcH)2(OH2)2]. 2H2O (3); at higher pH in the presence of excess hydroxide, a highly porous, three-dimensional material was obtained, [Co3(micro3-OH)2(2,4-pdc)2] x 9H2O (4a). 4a contains cobalt hydroxide chains, whose magnetic behavior has been studied in detail by neutron diffraction. A Ni(II)-containing analogue was also prepared using NiCI2 (4b), which shows weak antiferromagnetic coupling. Attempts to obtain a Zn(II)-based analogue of the porous material 4 gave instead a unique coordination material, [Zn(micro2-OH)2(2,4-pdc)] (5), which contains uncommon zinc hydroxide bridging modes. PMID:20352809

Humphrey, Simon M; Weldon, Gerald F; Wood, Paul T

2010-01-01

163

Exact solution of the one-dimensional Hubbard model with arbitrary boundary magnetic fields  

NASA Astrophysics Data System (ADS)

The one-dimensional Hubbard model with arbitrary boundary magnetic fields is solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz in the charge sector, the second eigenvalue problem associated with the spin sector is constructed. It is shown that the second eigenvalue problem can be transformed into that of the inhomogeneous XXX spin chain with arbitrary boundary fields which can be solved via the off-diagonal Bethe ansatz method.

Li, Yuan-Yuan; Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

2014-02-01

164

Ferromagnetic order in the one-dimensional Anderson lattice  

NASA Astrophysics Data System (ADS)

Using bosonization an effective Hamiltonian is derived for the one-dimensional Anderson lattice model in the Toulouse limit. The effective Hamiltonian exhibits ferromagnetic ground state in the intermediate coupling regime.

Gulacsi, M.

2015-01-01

165

Weakly Interacting Bose Gas in the One-Dimensional Limit  

E-print Network

We prepare a chemically and thermally one-dimensional (1D) quantum degenerate Bose gas in a single microtrap. We introduce a new interferometric method to distinguish the quasicondensate fraction of the gas from the thermal ...

Kruger, P.

166

Static electric field in one-dimensional insulators without boundaries  

E-print Network

In this brief report, we show that in a one-dimensional insulating system with periodic boundary conditions, the coefficient of the ? term in the effective theory is not only determined by the topological index ?i?[superscript ...

Chen, Kuang-Ting

167

Quantum correlation in one-dimensional extended quantum compass model  

NASA Astrophysics Data System (ADS)

We study the correlations in the one-dimensional extended quantum compass model in a transverse magnetic field. By exactly solving the Hamiltonian, we find that the quantum correlation of the ground state of one-dimensional quantum compass model is vanishing. We show that quantum discord can not only locate the quantum critical points, but also discern the orders of phase transitions. Furthermore, entanglement quantified by concurrence is also compared.

You, W. L.

2012-02-01

168

Model System for a One-Dimensional Magnetic Photonic Crystal  

Microsoft Academic Search

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a ``magnetic atom.'' Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric

S. Linden; M. Decker; M. Wegener

2006-01-01

169

Flexible Two-Dimensional Square-Grid Coordination Polymers: Structures and Functions  

PubMed Central

Coordination polymers (CPs) or metal-organic frameworks (MOFs) have attracted considerable attention because of the tunable diversity of structures and functions. A 4,4?-bipyridine molecule, which is a simple, linear, exobidentate, and rigid ligand molecule, can construct two-dimensional (2D) square grid type CPs. Only the 2D-CPs with appropriate metal cations and counter anions exhibit flexibility and adsorb gas with a gate mechanism and these 2D-CPs are called elastic layer-structured metal-organic frameworks (ELMs). Such a unique property can make it possible to overcome the dilemma of strong adsorption and easy desorption, which is one of the ideal properties for practical adsorbents. PMID:21152303

Kajiro, Hiroshi; Kondo, Atsushi; Kaneko, Katsumi; Kanoh, Hirofumi

2010-01-01

170

Electrical conductivity and luminescence properties of two silver(I) coordination polymers with heterocyclic nitrogen ligands  

NASA Astrophysics Data System (ADS)

The synthesis and X-ray structural characterization of two novel silver(I) coordination polymers, [Ag(NO3)(quin)]n (1) and [Ag8(HL)2(H2O)4(mpyz)]·3H2O (2) are reported, where quin=5,6,7,8-tetrahydroquinoxaline, H6L=cyclohexane-1,2,3,4,5,6-hexacarboxylic acid and mpyz=2-methyl pyrazine. The single crystal diffraction analyses showed that complex 1 is a 2D layered structure, while 2 presents a 3D polymeric architecture. In complex 2 the network is stabilized by argentophilic interactions and hydrogen bonding. Electrical conductivity of order 3×10-4 Scm-1 (1) and 1.6×10-4 Scm-1 (2) is measured on thin film specimen at room temperature. The photoluminescence and thermal properties of the complexes have also been studied.

Rana, Abhinandan; Kumar Jana, Swapan; Pal, Tanusri; Puschmann, Horst; Zangrando, Ennio; Dalai, Sudipta

2014-08-01

171

A 3D chiral porous In(III) coordination polymer with PtS topological net.  

PubMed

The solvothermal reaction of In(III) and 1,2,4,5-benzeneteracarboxylic acid with the presence of piperazine leads to the generation of a novel 3D chiral porous coordination polymer with PtS topological net. Interestingly, the resulting crystals were not a racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using solid vibrational circular dichroism (VCD) spectra and the solid circular dichroism (CD) spectra based on large crystals from one crystallization. High-pressure CO(2) and CH(4) adsorption measurement at 298 K reveals that activated 1 can absorb 45.8 cm(3) (STP)/g CO(2) at 22 atm and 22.5 cm(3) (STP)/g CH(4) at 25 atm. PMID:21822520

Han, Zheng-Bo; Li, Bi-Ye; Ji, Jian-Wei; Du, Yi-En; An, Hai-Yan; Zeng, Ming-Hua

2011-09-28

172

Synthesis and characterization of two unsquare 4-connected 2D coordination polymers with helical character  

NASA Astrophysics Data System (ADS)

Under hydrothermal conditions, two 2D coordination polymers based on methylenediisophthalic acid (H4L) and 1,2-bis(imidazole-1-ylmethyl)benzene/1,3-bis(imidazole-1-ylmethyl)benzene (o-bix/m-bix) connectors were prepared and characterized by single crystal X-ray diffraction, IR and TG analysis. The structural analysis shows that complexes 1-2 have interesting unsquare 4-connected topological nets. Complex 1 has the Schläfli symbol (32.4.62.7)2(32.62.72) with the distorted ?-W net and complex 2 has the seldom reported Schläfli symbol (3.4.5.62.7)2(3.42.52.7). Moreover, there exist 1D helical chains [M2(bix)2]? (M = NiII and CoII) in 2D chiral layer of 1 and 2D nonchiral layer of 2.

Duan, Xian-Ying; Zhao, Jun-Hong; Wei, Mei-Lin

2014-01-01

173

Chirality detection of two enantiomorphic 3D lanthanide coordination polymers by vibrational circular dichroism spectra.  

PubMed

Two enantiomorphic 3D lanthanide coordination polymers of {[Dy5(L)4(H2O)10][Dy(H2O)7][Na(H2O)5]}·(ClO4)7·(H2O)15 ( for R and for S) with chiral helical chains were synthesized based on an achiral ligand N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (H3L) and Dy(ClO4)3. Crystal analysis revealed that and were crystallized in chiral space groups P4132 and P4332, respectively. The absolute configurations of the two structures were evidenced by vibrational circular dichroism (VCD) spectra with one single crystal sample. PMID:25710701

Zheng, Xiu-Ying; Zhang, Han; Cao, Ling-Yun; Kong, Xiang-Jian; Long, La-Sheng; Zheng, Lan-Sun

2015-03-10

174

Pressure-induced amorphization of a dense coordination polymer and its impact on proton conductivity  

SciTech Connect

The proton conductivity of a dense coordination polymer (CP) was investigated under high-pressure conditions. Impedance measurements under high pressures revealed that the proton conductivity of the CP decreased more than 1000-fold at pressures of 3–7 GPa and that the activation energy for proton conduction almost doubled compared with that at ambient pressure. A synchrotron X-ray study under high pressure identified the amorphization process of the CP during compression, which rationally explains the decrease in conductivity and increase in activation energy. This phenomenon is categorized as reversible pressure-induced amorphization of a dense CP and is regarded as a demonstration of the coupling of the mechanical and electrical properties of a CP.

Umeyama, Daiki; Hagi, Keisuke; Ogiwara, Naoki [Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Horike, Satoshi, E-mail: horike@sbchem.kyoto-u.ac.jp, E-mail: kitagawa@icems.kyoto-u.ac.jp [Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Tassel, Cedric [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); The Hakubi Center for Advanced Research, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan); Kageyama, Hiroshi [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Higo, Yuji [Japan Synchrotron Radiation Research Institute, Hyogo 679-5198 (Japan); Kitagawa, Susumu, E-mail: horike@sbchem.kyoto-u.ac.jp, E-mail: kitagawa@icems.kyoto-u.ac.jp [Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan)

2014-12-01

175

Synthesis, crystal structure and photoluminescent properties of four lanthanide 5-nitroisophthalate coordination polymers  

SciTech Connect

Four new lanthanide coordination polymers, [Y(Hnip)(nip)(H{sub 2}O)].H{sub 2}O (1), [Ln(Hnip)(nip)(H{sub 2}O){sub 2}].2H{sub 2}O [Ln=Eu(2), Tb(3)] and [Y(nip){sub 2}].(H{sub 2}4,4'-bpy){sub 0.5} (4) [5-nip=5-nitroisophthalate, 4,4'-bpy=4,4'-bipyridine], have been hydrothermally synthesized and structurally characterized. Compound 1 features novel lanthanide-carboxylate groups chains composed of three samehanded helical strands intersecting each other through hinged lanthanide atoms, and these chains are cross-linked by phenylene moieties of carboxylate ligands into a 2D layer structure. Compounds 2 and 3 are isomorphous, and contain 1D catenanelike Ln-O-C-O-Ln chains, which are interconnected by phenylene moieties into 2D layer structures. Compound 4, however, displays a 3D architecture sustained by strong hydrogen bonding interactions between the protonated 4,4'-bpy and the carboxyl oxygen atom from [Y{sub 2}(nip){sub 4}]{sup 2-} with 2D layer structure, and 4,4'-bpy as the guest molecules exist in bilayer channel. The studies for the thermal stabilities of the four compounds show that compound 4 is more stable than other compounds. Compound 2 emits characteristic red luminescence of Eu{sup 3+} ions at room temperature, and its luminescent lifetime and quantum efficiency has been determined. - Graphical abstract: Four lanthanide 5-nitroisophthalate coordination polymers have been hydrothermally prepared and resent different structures and thermal stabilities and photoluminescence properties.

Huang Yan [Department of Chemistry, Tongji University, Shanghai 200092 (China); Yan Bing, E-mail: byan@tongji.edu.c [Department of Chemistry, Tongji University, Shanghai 200092 (China); State Key Lab of Coordination Chemistry, Nanjing University, Nanjing 210093 (China); Shao Min [Department of Chemistry, College of Science, Shanghai University, Shanghai 200444 (China)

2009-04-15

176

Mechanism of ultrasound scission of a silver-carbene coordination polymer.  

PubMed

Scission of a supramolecular polymer-metal complex can be carried out using collapsing cavitation bubbles created by ultrasound. Although the most plausible scission mechanism of the coordinative bonds is through mechanical force, the influence of radicals and high hot-spot temperatures on scission has to be considered. A silver(I)-N-heterocyclic carbene complex was exposed to 20 kHz ultrasound in argon, nitrogen, methane, and isobutane saturated toluene. Scission percentages were almost equal under argon, nitrogen, and methane. Radical production differs by a factor of 10 under these gases, indicating that radical production is not a significant contributor to the scission process. A model to describe the displacement of the bubble wall, strain rates, and temperature in the gas shows that critical strain rates for coil-to-stretch transition, needed for scission, are achieved at reactor temperatures of 298 K, an acoustic pressure of 1.2 × 10(5) Pa, and an acoustic frequency of 20 kHz. Lower scission percentages were measured under isobutane, which also shows lower strain rates in model simulations. The activation of the polymer-metal complexes in toluene under the influence of ultrasound occurs through mechanical force. PMID:21827184

Rooze, Joost; Groote, Ramon; Jakobs, Robert T M; Sijbesma, Rint P; van Iersel, Maikel M; Rebrov, Evgeny V; Schouten, Jaap C; Keurentjes, Jos T F

2011-09-29

177

Carboxyl group (-CO2 H) functionalized coordination polymer nanoparticles as efficient platforms for drug delivery.  

PubMed

Functionalization of nanoparticles can significantly influence their properties and potential applications. Although researchers can now functionalize metal, metal oxide, and organic polymer nanoparticles with a high degree of precision, controlled surface functionalization of nanoscale coordination polymer particles (CPPs) has remained a significant challenge. The lack of methodology is perhaps one of the greatest roadblocks to the advancement of CPPs into high added-value drug delivery applications. Here, we report having achieved this goal through a stepwise formation and functionalization protocol. We fabricated robust nanoparticles with enhanced thermal and colloidal stabilities by incorporation of carboxyl groups and these surface carboxyl groups could be subsequently functionalized through well-known peptide coupling reactions. The set of chemistries that we employed as proof-of-concept enabled a plethora of new functional improvements for the application of CPPs as drug delivery carriers, including enhanced colloidal stabilities and the incorporation of additional functional groups such as polyethylene glycol (PEG) or fluorescent dyes that enabled tracking of their cellular uptake. Finally, we ascertained the cytotoxicity of the new CPP nanoparticles loaded with camptothecin to human breast adenocarcinoma (MCF-7). Efflux measurements show that the encapsulation of camptothecin enhances the potency of the drug 6.5-fold and increases the drug retention within the cell. PMID:25284328

Novio, Fernando; Lorenzo, Julia; Nador, Fabiana; Wnuk, Karolina; Ruiz-Molina, Daniel

2014-11-17

178

Four homochiral coordination polymers contain N-acetyl-L-tyrosine and different N-donor ligand: Influence of metal cations, ancillary ligands and coordination modes  

SciTech Connect

Using the chiral ligand N-acetyl-L-tyrosine (Hacty) and maintaining identical reaction conditions, Zn(II), Co(II), and Cd(II) salts provided four novel homochiral coordination polymers ([Zn(acty)(bipy){sub 2}(H{sub 2}O){sub 2}]·NO{sub 3}·2H{sub 2}O){sub n}1, ([Co(acty)(bipy){sub 2}(H{sub 2}O){sub 2}]·NO{sub 3}·2H{sub 2}O){sub n}2, ([Cd(acty){sub 2}(bipy)H{sub 2}O]·H{sub 2}O){sub n}3, and ([Cd(acty)(bpe){sub 2}(Ac)]·6H{sub 2}O){sub n}4 (bipy=4,4?-bipyridine; bpe=1,2-di(4-pyridyl)ethane) in the presence of ancillary ligands. Compounds 1 and 2 are isostructural 1D chain structures. The neighboring chains are further linked into a 3D supramolecular structure via ??? stacking and hydrogen bond interactions. Compound 3 shows a 2D network and 4 generates 1D infinite chains along the c-axis. Compounds 3 and 4 are further connected into 3D supramolecular network by hydrogen bond interactions. More importantly, coordination in acyl oxygen atoms and ancillary ligands (bpe) as monodentate decorating ligands in 4 are rarely reported. Ancillary ligands and metal cations significantly influence the structure of the complexes. The photoluminescence properties of 1, 3, and 4 were studied at room temperature. Circular dichroism (CD) of the complexes have been investigated. - Graphical abstract: Four new homochiral coordination polymers were prepared and structurally characterized, which investigate the influence of the ancillary ligands and metal ions on the design and synthesis of coordination polymers. Display Omitted - Highlights: • It is rarely reported that the chiral coordination polymers prepared with N-acetyl-L-tyrosine ligands. • The alkalescent acetyl oxygen atom is difficult to participate in coordination but it is happened in the N-acetyl-L-tyrosine ligands. • The ancillary ligands (4,4?-bipy and bpe) are present in an unusual coordination modes, monodentate decorating ligands in 1, 2 and 4. • Structure comparative analyses results indicate that the secondary ligands and metal ions influence the fabrication of these inorganic–organic arrangements.

Li, Meng-Li; Song, Hui-Hua, E-mail: flower9486@163.com

2013-10-15

179

A ratiometric and colorimetric luminescent thermometer over a wide temperature range based on a lanthanide coordination polymer.  

PubMed

A lanthanide coordination polymer Tb0.957Eu0.043cpda was synthesized as a ratiometric and colorimetric luminescent thermometer. The high triplet excited state energy of a linker enables Tb0.957Eu0.043cpda to detect and visualize temperature over a wide range from cryogenic to room temperature (40-300 K). PMID:24287968

Cui, Yuanjing; Zou, Wenfeng; Song, Ruijing; Yu, Jiancan; Zhang, Wenqian; Yang, Yu; Qian, Guodong

2014-01-21

180

Structural and magnetic ordering in the two-dimensional coordination polymer Co(ox)(bpy-d8),  

E-print Network

Structural and magnetic ordering in the two-dimensional coordination polymer Co(ox)(bpy-d8), (ox C-range antiferromagnetic ordering due to much weaker interchain magnetic interactions. The magnetically ordered structure. Inorganic compounds; C. Neutron scattering; D. Crystal structure; D. Magnetic properties; D. Magnetic

Li, Jing

181

Structural change of supramolecular coordination polymers of itaconic acid and 1,10-phenanthroline along lanthanide series  

E-print Network

interest [28­34]. Succinic acid (SCA) as a representative of flexible dicarboxylic acids has been widely usStructural change of supramolecular coordination polymers of itaconic acid and 1,10-phenanthroline of lanthanide chlorides with itaconic acid (H2IA) and 1,10-phenanthroline (phen), and struc- turally

Gao, Song

182

A linear heterometallic bismuth-copper coordination polymer containing two types of organic ligands.  

PubMed

In the linear coordination polymer catena-poly[[[aqua(1,10-phenanthroline-?(2)N,N')copper(II)]-?-pyridine-2,6-dicarboxylato-?(4)O(2):O(2'),N,O(6)-[(nitrato-?(2)O,O')bismuth(III)]-?-pyridine-2,6-dicarboxylato-?(4)O(2),N,O(6):O(6')] dihydrate], {[Bi(III)Cu(II)(C7H3NO4)2(NO3)(C12H8N2)(H2O)]·2H2O}n, the Bi(III) cation is O,N,O'-chelated by the two pyridine-2,6-dicarboxylate ligands and O,O'-chelated by the nitrate anion, the nine coordinating atoms conferring a tricapped trigonal prismatic environment on the metal centre. Each pyridine-2,6-dicarboxylate ligand uses one of its carboxylate O atoms to bind to an aqua(1,10-phenanthroline)copper(II) unit, the Cu-O dative bonds giving rise to the formation of a ribbon motif. The Cu(II) cation exhibits a square-pyramidal geometry. The ribbon motif propagates along the shortest axis of the triclinic unit cell and the solvent water molecules are hydrogen bonded to the same ribbon. PMID:25652275

Yue, Zi-Long; Feng, Yu-Quan; Ng, Seik Weng

2015-02-01

183

Predicting adsorption in one-dimensional zeolite pores with the exact theory of one-dimensional hard rods  

NASA Astrophysics Data System (ADS)

The exact statistical mechanical theory of a one-dimensional hard-rod fluid in an arbitrary external field is applied to the adsorption of simple molecules into nearly one-dimensional zeolitic pores, using a zeolite-sorbent interaction potential based on the system of xenon in mordenite. The effect is explored of changing the zeolite-sorbent interaction on adsorption. By optimizing one parameter in the model, the results of this theory compare well with experimental isotherms of xenon in mordenite.

Mitchell, Martha C.; McCormick, Alon V.; Davis, H. Ted

184

Complementary in situ reactivity of isomeric dipyridylamide precursors and its effect on dimensionality of cadmium 5-nitroisophthalate coordination polymers  

NASA Astrophysics Data System (ADS)

Hydrothermal treatment of cadmium nitrate, 5-nitroisophthalic acid (H2nip) and one of two isomeric dipyridylamides resulted in coordination polymer crystalline solids that manifested different in situ reactivity and dimensionality, as ascertained by single crystal X-ray diffraction. Hydrolysis of 3-pyridylisonicotinamide (3-pina) afforded the 3-aminopyridine (3-ampyr) ligands observed in the 1-D ladder polymer {[Cd(nip)(3-ampyr)(H2O)]?2H2O}n (1). Conversely, hydrolysis of the isomeric precursor 3-pyridylnicotinamide (3-pna) generated the monoanionic nicotinate ligands in the 2-D coordination polymer [Cd2(nip)(nic)2(H2O)2]n (2). Compound 2 displays {Cd2(OCO)2} eight-membered ring dimeric units linked into (6,3) graphite-type slab motifs. Luminescent properties of these two new materials are also presented.

O'Donovan, Megan E.; LaDuca, Robert L.

2014-07-01

185

Hydrothermal reactions: From the synthesis of ligand to new lanthanide 3D-coordination polymers  

SciTech Connect

The organic ligand 2,5-piperazinedione-1,4-diacetic acid (H{sub 2}PDA) was synthesized under hydrothermal conditions starting from the iminodiacetic acid and catalyzed by oxalic acid. The X-ray powder diffraction data indicates that the compound crystallizes in the P2{sub 1}/c monoclinic system as reported in the literature. The ligand was also characterized by elemental analysis, magnetic nuclear resonance, infrared spectroscopy and thermogravimetric analysis. Two new coordination networks based on lanthanide ions were obtained with this ligand using hydrothermal reaction. In addition to single-crystal X-ray diffraction, the compounds were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and elemental analysis. Single-crystal XRD showed that the compounds are isostructural, crystallizing in P2{sub 1}/n monoclinic system with chemical formula [Ln(PDA){sub 1.5}(H{sub 2}O)](H{sub 2}O){sub 3} (Ln=Gd{sup 3+}(1) and Eu{sup 3+}(2)).The luminescence properties of both compounds were studied. In the compound (1), a broad emission band was observed at 479 nm, redshifted by 70 nm in comparison of the free ligand. In (2), the typical f–f transition was observed with a maximum peak at 618 nm, related with the red emission of the europium ions. Computational methods were performed to simulate the crystal structure of (2). The theoretical calculations of the intensity parameters are in good agreement with the experimental values. - Graphical abstract: Scheme of obtaining the ligand 2,5-piperazinedione-1,4-diacetic acid (H{sub 2}PDA) and two new isostructural 3D-coordination polymers [Ln(PDA){sub 1.5}(H{sub 2}O)](H{sub 2}O){sub 3} (Ln=Gd{sup 3+} and Eu{sup 3+}) by hydrothermal synthesis. Display Omitted - Highlights: • The ligand 2,5-piperazinedione-1,4-diacetic acid was synthetized using the hydrothermic method and characterized. • Two new 3D-coordination polymers with this ligand containing Gd{sup 3+} and Eu{sup 3+} ions were also obtained. • The compounds are isostructural and the typical luminescent properties were observed in both structures.

Silva, Fausthon Fred da; Fernandes de Oliveira, Carlos Alberto; Lago Falcão, Eduardo Henrique [Laboratório de Terras Raras, Departamento de Química Fundamental, Universidade Federal de Pernambuco (DQF-UFPE), 50590-470 Recife, PE (Brazil); Gatto, Claudia Cristina [Laboratório de Síntese Inorgânica e Cristalografia, Instituto de Química, Universidade de Brasília (IQ-UnB), 70904-970 Brasilia, DF (Brazil); Bezerra da Costa, Nivan; Oliveira Freire, Ricardo [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Chojnacki, Jaros?aw [Department of Inorganic Chemistry, Gdansk University of Technology, 80-233 Gdansk (Poland); Alves Júnior, Severino, E-mail: salvesjr@ufpe.br [Laboratório de Terras Raras, Departamento de Química Fundamental, Universidade Federal de Pernambuco (DQF-UFPE), 50590-470 Recife, PE (Brazil)

2013-11-15

186

Ion conductivity and transport by porous coordination polymers and metal-organic frameworks.  

PubMed

Ion conduction and transport in solids are both interesting and useful and are found in widely distinct materials, from those in battery-related technologies to those in biological systems. Scientists have approached the synthesis of ion-conductive compounds in a variety of ways, in the areas of organic and inorganic chemistry. Recently, based on their ion-conducting behavior, porous coordination polymers (PCPs) and metal-organic frameworks (MOFs) have been recognized for their easy design and the dynamic behavior of the ionic components in the structures. These PCP/MOFs consist of metal ions (or clusters) and organic ligands structured via coordination bonds. They could have highly concentrated mobile ions with dynamic behavior, and their characteristics have inspired the design of a new class of ion conductors and transporters. In this Account, we describe the state-of-the-art of studies of ion conductivity by PCP/MOFs and nonporous coordination polymers (CPs) and offer future perspectives. PCP/MOF structures tend to have high hydrophilicity and guest-accessible voids, and scientists have reported many water-mediated proton (H(+)) conductivities. Chemical modification of organic ligands can change the hydrated H(+) conductivity over a wide range. On the other hand, the designable structures also permit water-free (anhydrous) H(+) conductivity. The incorporation of protic guests such as imidazole and 1,2,4-triazole into the microchannels of PCP/MOFs promotes the dynamic motion of guest molecules, resulting in high H(+) conduction without water. Not only the host-guest systems, but the embedding of protic organic groups on CPs also results in inherent H(+) conductivity. We have observed high H(+) conductivities under anhydrous conditions and in the intermediate temperature region of organic and inorganic conductors. The keys to successful construction are highly mobile ionic species and appropriate intervals of ion-hopping sites in the structures. Lithium (Li(+)) and other ions can also be transported. If we can optimize the crystal structures, this could offer further improvements in terms of both conductivity and the working temperature range. Another useful characteristic of PCP/MOFs is their wide application to materials fabrication. We can easily prepare heterodomain crystal systems, such as core-shell or solid solution. Other anisotropic morphologies (thin film, nanocrystal, nanorod, etc.,) are also possible, with retention of the ion conductivity. The flexible nature also lets us design morphology-dependent ion-conduction behaviors that we cannot observe in the bulk state. We propose (1) multivalent ion and anion conductions with the aid of redox activity and defects in structures, (2) control of ion transport behavior by applying external stimuli, (3) anomalous conductivity at the hetero-solid-solid interface, and (4) unidirectional ion transport as in the ion channels in membrane proteins. In the future, scientists may use coordination polymers not only to achieve higher conductivity but also to control ion behavior, which will open new avenues in solid-state ionics. PMID:23730917

Horike, Satoshi; Umeyama, Daiki; Kitagawa, Susumu

2013-11-19

187

One dimensional speckle fields generated by three phase level diffusers  

NASA Astrophysics Data System (ADS)

Speckle patterns have usually been obtained by using ground glass as random diffusers. Liquid-crystal spatial light modulators have opened the possibility of engineering tailored speckle fields obtained from designed diffusers. In this work, one-dimensional Gaussian speckle fields with fully controllable features are generated. By employing a low-cost liquid-crystal spatial light modulator, one-dimensional three phase level diffusers are implemented. These diffusers make it possible to control average intensity distribution and statistical independence among the generated patterns. The average speckle size is governed by an external slit pupil. A theoretical model to describe the generated speckle patterns is developed. Experimental and theoretical results confirming the generation of one-dimensional speckle fields are presented. Some possible applications of these speckles, such as atom trapping and super-resolution imaging, are briefly envisaged.

Cabezas, L.; Amaya, D.; Bolognini, N.; Lencina, A.

2015-02-01

188

One-dimensional rainbow thermometry system by using slit apertures.  

PubMed

A new rainbow thermometry system by using slit apertures and a laser light sheet, called a one-dimensional rainbow thermometry (ORT) system, has been developed as an extension of global rainbow thermometry (GRT). This system is capable of one-dimensional or line measurements of the size and refractive index of droplets in the spray space, while the conventional GRT system is normally considered a typical "single-point" or "small volume" measurement method. The performance of this new system was tested and verified with both water and ethanol spray. The results show the feasibility and potential of ORT in simultaneous and one-dimensional measurement of the size and refractive index of liquid droplets, especially in the research field of spray evaporation and combustion. PMID:24487885

Wu, Xuecheng; Jiang, Haoyu; Wu, Yingchun; Song, Jin; Gréhan, Gérard; Saengkaew, Sawitree; Chen, Linghong; Gao, Xiang; Cen, Kefa

2014-02-01

189

Equilibration of a one-dimensional quantum liquid  

SciTech Connect

We review some of the recent results on equilibration of one-dimensional quantum liquids. The low-energy properties of these systems are described by the Luttinger liquid theory, in which the excitations are bosonic quasiparticles. At low temperatures, the relaxation of the gas of excitations toward full equilibrium is exponentially slow. In electronic Luttinger liquids, these relaxation processes involve backscattering of electrons and give rise to interesting corrections to the transport properties of one-dimensional conductors. We focus on the phenomenological theory of the equilibration of a quantum liquid and obtain an expression for the relaxation rate in terms of the excitation spectrum.

Matveev, K. A., E-mail: matveev@anl.gov [Argonne National Laboratory Argonne, Materials Science Division (United States)

2013-09-15

190

One-dimensional quasistatic model of biodegradable elastic curved rods  

NASA Astrophysics Data System (ADS)

In this paper, we derive and analyze a one-dimensional model of biodegradable elastic curved rods. The model is given for displacement and degradation as unknown functions and is nonlinear. It is obtained from the three-dimensional equations of the biodegradable elastic rod-like bodies using formal asymptotic expansion techniques with respect to the small thickness of the rod. Existence and uniqueness of the solution of the one-dimensional model are proved. Some qualitative properties of the model are also obtained from the numerical approximation of the model.

Tamba?a, Josip; Žugec, Bojan

2015-03-01

191

Model system for a one-dimensional magnetic photonic crystal.  

PubMed

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a "magnetic atom." Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric slab waveguide, giving rise to an avoided crossing at near-infrared wavelengths. Our experimental findings are in excellent agreement with theory. PMID:17026307

Linden, S; Decker, M; Wegener, M

2006-08-25

192

Model System for a One-Dimensional Magnetic Photonic Crystal  

NASA Astrophysics Data System (ADS)

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a “magnetic atom.” Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric slab waveguide, giving rise to an avoided crossing at near-infrared wavelengths. Our experimental findings are in excellent agreement with theory.

Linden, S.; Decker, M.; Wegener, M.

2006-08-01

193

Hybrid surface-relief/volume one dimensional holographic gratings  

NASA Astrophysics Data System (ADS)

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

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

2015-04-01

194

Exact Canonically Conjugate Momenta Approach to a One-Dimensional Neutron-Proton System, I  

E-print Network

Introducing collective variables, a collective description of nuclear surface oscillations has been developed with the first quantized language, contrary to the second quantized one in Sunakawa's approach for a Bose system. It overcomes difficulties remaining in the traditional theories of nuclear collective motions:$\\!$ Collective momenta are not exact canonically conjugate to collective coordinates and are not independent. On the contrary to such a description, Tomonaga first gave the basic idea to approach elementary excitations in a one-dimensional Fermi system. The Sunakawa's approach for a Fermi system is also expected to work well for such a problem. In this paper, on the $isospin$ space, we define a density operator and further following Tomonaga, introduce a collective momentum. We propose an $exact$ canonically momenta approach to a one-dimensional neutron-proton system under the use of the Grassmann variables.

Seiya Nishiyama; Joao da Providencia

2015-03-10

195

A series of Zn-4f heterometallic coordination polymers and a zinc complex containing a flexible mixed donor dicarboxylate ligand.  

PubMed

A new zinc compound, together with a corresponding series of Zn-4f heterometallic coordination polymers, namely, [Zn(H2PBDA)(PBDA)]n (1), {[Ln2(PBDA)2·2H2O] [Zn2(PBDA)2Cl2]}n [H2PBDA = 3-(pyridin-3-yl-oxy) benzene-1,2-dicarboxylic acid, and Ln = Pr(2), Nd(3), Eu(4), Gd(5), Dy(6), Ho(7), Er(8)] have been hydrothermally synthesized and characterized systematically. Polymers 2-8 feature two-dimensional (2D) 4,4 networks, containing the original 1D heterometallic double stranded chains composed of [Ln2Zn2(PBDA)2] entities. The extensive hydrogen bonding and ?-? stacking interactions were observed to stabilize the extended architectures. The luminescence emission spectra of the polymers vary depending on the lanthanide(III) ion present. Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers. In addition, polymer 6 exhibits an interesting slow magnetic relaxation behavior at lower temperatures. PMID:23549773

Feng, Xun; Feng, Yu-Quan; Liu, Lang; Wang, Li-Ya; Song, Hong-Liang; Ng, Seik-Weng

2013-06-01

196

Toward precise solution of one-dimensional velocity inverse problems  

SciTech Connect

A family of one-dimensional inverse problems are considered with the goal of reconstructing velocity profiles to reasonably high accuracy. The travel-time variable change is used together with an iteration scheme to produce an effective algorithm for computation. Under modest assumptions the scheme is shown to be convergent.

Gray, S.; Hagin, F.

1980-01-01

197

Teaching Module for One-Dimensional, Transient Conduction.  

ERIC Educational Resources Information Center

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

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

1998-01-01

198

Transition density of one-dimensional diffusion with discontinuous drift  

NASA Technical Reports Server (NTRS)

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

Zhang, Weijian

1990-01-01

199

Analysis of spectral operators in one-dimensional domains  

NASA Technical Reports Server (NTRS)

Results are proven concerning certain projection operators on the space of all polynomials of degree less than or equal to N with respect to a class of one-dimensional weighted Sobolev spaces. The results are useful in the theory of the approximation of partial differential equations with spectral methods.

Maday, Y.

1985-01-01

200

One-dimensional barcode reading: an information theoretic approach  

E-print Network

One-dimensional barcode reading: an information theoretic approach Karim Houni,1, * Wadih Sawaya,1-data transmission, the barcode found its place as the simplest and the most pervasive solution for new uses point of view, a barcode is a singular coding based on a graphical representation of the information

Paris-Sud XI, Université de

201

Contemporary Mathematics Time reversal for inclusion detection in one dimensional  

E-print Network

. Primary 60G35, 60F05; Secondary 34Q62, 35L05. Key words and phrases. Detection, Time reversal, RandomContemporary Mathematics Time reversal for inclusion detection in one dimensional randomly layered introduce a technique based on time reversal which can take advantage of both the coherent time

Solna, Knut

202

Exponential decay in one-dimensional porous-thermo-elasticity  

E-print Network

follows we consider a theory for the behavior of porous solids such that the matrix material is elastic of porous elastic material has been established by Cowin and Nunziato [12, 13, 14]. In this theory the bulkExponential decay in one-dimensional porous-thermo-elasticity Pablo S. Casas Dept. Matem

Politècnica de Catalunya, Universitat

203

Reduction of periodic one-dimensional hopping model  

E-print Network

In this research, methods of reducing a general periodic one-dimensional hopping model to a one- or two-state model, which keeps the basic properties of the original process, are discussed. This reduction also implies that, to some extent, many processes can be well described by simple two-state or even one-state models.

Yunxin Zhang

2010-07-04

204

Structure-borne sound Finite one-dimensional structures  

E-print Network

;3 Structure-borne sound · Wave-train-closure principle Structure-borne sound · Ideal boundary conditions »Flexural vibrations v+ Incident propagating wave Structure-borne sound · x L S · Finite one-dimensional structures »Flexural vibrations vj Incident evanescent wave #12;5 Structure-borne sound · x L S · Finite one

Berlin,Technische Universität

205

Approximate Approaches to the One-Dimensional Finite Potential Well  

ERIC Educational Resources Information Center

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

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

2011-01-01

206

Statistical mechanics of a one-dimensional lattice gas  

Microsoft Academic Search

We study the statistical mechanics of an infinite one-dimensional classical lattice gas. Extending a result ofvan Hove we show that, for a large class of interactions, such a system has no phase transition. The equilibrium state of the system is represented by a measure which is invariant under the effect of lattice translations. The dynamical system defined by this invariant

D. Ruelle

1968-01-01

207

Optimal One-Dimensional Relay Placement in Cognitive Radio Networks  

E-print Network

Optimal One-Dimensional Relay Placement in Cognitive Radio Networks Junhua Zhu and Jianwei Huang for a secondary user in a cognitive radio network subject to outage constraints. With selection decode the approximation instead to solve the relay placement problem in cognitive radio networks. We find that the optimal

Huang, Jianwei

208

Automated alignment of one-dimensional chromatographic fingerprints  

Microsoft Academic Search

A general framework for the automatic alignment of one-dimensional chromatographic signals is presented in this article. The alignment of signals was achieved by explicitly modeling the warping function. Its shape was estimated using a linear combination of several B-spline functions. The coefficients of the spline functions were found in the course of an optimization procedure to maximize the Pearson's correlation

M. Daszykowski; Y. Vander Heyden; C. Boucon; B. Walczak

2010-01-01

209

ACOUSTIC WAVE TRAPPING IN ONE-DIMENSIONAL AXISYMMETRIC ARRAYS  

E-print Network

ACOUSTIC WAVE TRAPPING IN ONE- DIMENSIONAL AXISYMMETRIC ARRAYS by M. MCIVER (Department 2011. Revise 2011] Summary The existence of acoustic, Rayleigh-Bloch modes in the vicinity of a one for the acoustic wave-field in the neighbourhood of such an array is obtained and solved with the use of a Galerkin

210

Superprism effect in one-dimensional magnetic photonic crystals  

NASA Astrophysics Data System (ADS)

So-called magnetic-superprism effect is studied consisting in an extremely large deviation of a light ray in a photonic crystal under the influence of an external magnetic field. It is demonstrated that the magnetic superprism effect is possible in one-dimensional magnetic photonic crystals.

Merzlikin, A. M.; Vinogradov, A. P.; Inoue, M.; Granovsky, A. B.

2008-05-01

211

Superprism effect in one-dimensional magnetic photonic crystals  

Microsoft Academic Search

So-called magnetic-superprism effect is studied consisting in an extremely large deviation of a light ray in a photonic crystal\\u000a under the influence of an external magnetic field. It is demonstrated that the magnetic superprism effect is possible in one-dimensional\\u000a magnetic photonic crystals.

A. M. Merzlikin; A. P. Vinogradov; M. Inoue; A. B. Granovsky

2008-01-01

212

Superprism effect in one-dimensional magnetic photonic crystals  

Microsoft Academic Search

So-called magnetic-superprism effect is studied consisting in an extremely large deviation of a light ray in a photonic crystal under the influence of an external magnetic field. It is demonstrated that the magnetic superprism effect is possible in one-dimensional magnetic photonic crystals.

A. M. Merzlikin; A. P. Vinogradov; M. Inoue; A. B. Granovsky

2008-01-01

213

One-dimensional inhomogeneous Ising model with periodic boundary conditions  

SciTech Connect

In this paper, we focus on the essential difference between the inhomogeneous one-dimensional Ising model with open and periodic boundary conditions. We show that, although the profile equation in the periodic case becomes highly nonlocal, due to a topological collective mode, there exists a local free-energy functional in an extended space and one can solve the inhomogeneous problem exactly.

Percus, J.K.; Zhang, M.Q.

1988-12-01

214

One-dimensional inhomogeneous Ising model with periodic boundary conditions  

Microsoft Academic Search

In this paper, we focus on the essential difference between the inhomogeneous one-dimensional Ising model with open and periodic boundary conditions. We show that, although the profile equation in the periodic case becomes highly nonlocal, due to a topological collective mode, there exists a local free-energy functional in an extended space and one can solve the inhomogeneous problem exactly.

J. K. Percus; M. Q. Zhang

1988-01-01

215

One-dimensional Ising model in arbitrary external field  

Microsoft Academic Search

The external potential needed to produce an arbitrary equilibrium density profile for a one-dimensional lattice gas with nearest neighbor interactions is solved exactly. The resulting sequence of direct correlation functions is shown to be of short range, and in the ferromagnetic case the even members alternate in sign at zero spin. The even Ursell distributions in this case likewise alternate

J. K. Percus

1977-01-01

216

Drift and diffusion in a one-dimensional disordered system  

Microsoft Academic Search

The low-frequency drift and diffusion coefficients in a one-dimensional diffusion model are determined. Of particular interest is the case of a constant bias and random hopping elements with a distribution which diverges for small values of the hopping elements. With use of the replica method this model is shown to be equivalent to a particle in a uniform magnetic field

Haim Weissman; Michael J. Stephen

1989-01-01

217

Diploma Thesis Bounds for One-dimensional Cellular Automata  

E-print Network

unbalanced words, shortest orphans and shortest diamonds of non-surjective one-dimensional CA. In this thesis Application: Bounding Unbalanced Words . . . . . . . . 18 3.3 Bounds for the Length of Shortest Orphans for Range-2 CA . . . . . . . . . . 20 3.4 Bounds for Many Orphans

Vollmer, Heribert

218

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

ERIC Educational Resources Information Center

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

Fan, Yale

2011-01-01

219

One-Dimensional NOE Experiments Using Pulsed Field Gradients  

Microsoft Academic Search

Previously, it has been shown that the use of pulsed field gradients in one-dimensional NOE experiments results in spectra of much higher quality than it has previously been possible to record. Such high-quality spectra make it possible to measure, with complete confidence, very small NOE enhancements and also make it straightforward to measure NOE buildup curves. In this paper, the

Katherine Stott; James Keeler; Que N. Van; A. J. Shaka

1997-01-01

220

Structure Determination of the One-Dimensional Compound Sr3ZnPtO6, Containing Zinc in a  

E-print Network

Structure Determination of the One-Dimensional Compound Sr3ZnPtO6, Containing Zinc in a HighlyVember 9, 1995 We report the synthesis and structure of a new zinc-containing strontium platinum oxide, Sr3ZnPtO6, in which zinc is present in a highly unusual trigonal prismatic coordination environment

zur Loye, Hans-Conrad

221

Peculiar Magnetic Transition Behaviour Around 208 K in One-dimensional Nickel(III) Chain Complex [1-(40  

E-print Network

Peculiar Magnetic Transition Behaviour Around 208 K in One-dimensional Nickel(III) Chain Complex [1 space group P21=c at room temperature.7 The coordination geometry of the nickel atom in the [Ni(mnt)2]Ã? between two positions about 1.63 #A apart, and one of which is modeled at 50% occupancy. The benzene ring

Gao, Song

222

Synthesis and characterization of the mixed ligand coordination polymer CPO-5  

NASA Astrophysics Data System (ADS)

The synthesis and crystal structures of a novel coordination polymer and its high-temperature variant are described. The as-synthesized material (CPO-5-as), of composition Zn(4,4'-bipyridine)(4,4'-biphenyldicarboxylate)·3H 2O, crystallizes in the triclinic space group P-1 (No. 2) with a=11.0197(2), b=14.2975(3), c=7.6586(1) Å, ?=95.9760(9)°, ?=108.026(1)°, ?=91.373(1)° and V=1139.16(4) Å 3. CPO-5-as is composed of tetrahedral zinc centers that are connected by the organic linkers to give five independent, interpenetrating diamond networks. In the structure, there is additional space for channels that are filled with three water molecules. These water molecules can be removed, leading to an anhydrous variant at 130 oC. CPO-5-130, of composition Zn(4,4'-bipyridine)(4,4'-biphenyldicarboxylate), crystallizes in the triclinic space group P-1 (No. 2) with a=11.1844(6), b=14.0497(7), c=7.7198(3) Å, ?=96.917(2)°, ?=109.527(2)°, ?=89.115(3)° and V=1134.6(1) Å 3. The structure of the five interpenetrating networks is virtually unchanged after the dehydration resulting in CPO-5-130 being a porous structure with an estimated free volume of 19.8%.

Kongshaug, Kjell Ove; Fjellvåg, Helmer

2003-11-01

223

Two coordination polymers of manganese(II) isophthalate and their preparation, structures, and magnetic properties  

SciTech Connect

Two manganese coordination polymers, [Mn{sub 2}(ip){sub 2}(dmf)]{center_dot}dmf (1) and [Mn{sub 4}(ip){sub 4}(dmf){sub 6}]{center_dot}2dmf (2) (ip=isophthalate; dmf=N,N-dimethylformamide), have been synthesized and characterized. X-ray crystal structural data reveal that compound 1 crystallizes in triclinic space group P-1, a=9.716(3) A, b=12.193(3) A, c=12.576(3) A, {alpha}=62.19(2) Degree-Sign , {beta}=66.423(17) Degree-Sign , {gamma}=72.72(2) Degree-Sign , Z=2, while compound 2 crystallizes in monoclinic space group Cc, a=19.80(3) A, b=20.20(2) A, c=18.01(3) A, {beta}=108.40(4) Degree-Sign , Z=4. Variable-temperature magnetic susceptibilities of compounds 1 and 2 exhibit overall weak antiferromagnetic coupling between the adjacent Mn(II) ions. - Graphical abstract: Three-dimensional porous and two-dimensional layered manganese isophthalates have been prepared. Magnetic susceptibility measurements exhibit overall weak antiferromagnetic interactions between the Mn(II) ions in both compounds. Highlights: Black-Right-Pointing-Pointer Two manganese isophthalates have been prepared. Black-Right-Pointing-Pointer Compound 1 adopts a three-dimensional porous structure. Black-Right-Pointing-Pointer Compound 2 adopts a two-dimensional layered structure. Black-Right-Pointing-Pointer Magnetic properties of both compounds are investigated.

Chen Jinxi, E-mail: chenjinxi@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Wang Jingjing [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Ohba, Masaaki [Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka (Japan)

2012-01-15

224

Filling pore space in a microporous coordination polymer to improve methane storage performance.  

PubMed

A strategy that allows the tuning of pore size in microporous coordination polymers (MCPs) through modification of their organic linkers is presented. When large substituents are introduced onto the linker, these pendent groups partially occupy the pores, thus reducing pore size while serving as additional adsorption sites for gases. The approach takes advantage of the fact that, for methane storage materials, small pores (0.4-0.8 nm in diameter) are more desirable than large pores since small pores promote optimal volumetric capacity. This method was demonstrated with IRMOF-8, a MCP constructed from Zn4O metal clusters and 2,6-naphthalenedicarboxylate (NDC) linkers. The NDC was functionalized through the addition of substituents including tert-butylethynyl or phenylethynyl groups. High pressure methane uptake demonstrates that the IRMOF-8 derivatives have significantly better performance than the unfunctionalized material in terms of both excess volumetric uptake and deliverable capacity. Moreover, IRMOF-8 derivatives also give rise to stronger interactions with methane molecules as shown by higher heat of adsorption values. PMID:25621891

Tran, Ly D; Feldblyum, Jeremy I; Wong-Foy, Antek G; Matzger, Adam J

2015-02-24

225

Spectroscopic properties and the catalytic activity of new organo-lead supramolecular coordination polymer containing quinoxaline.  

PubMed

The 3D-supramolecular coordination polymer (SCP) (3)?[ Cu2(CN)3(Me3Pb)(qox)], 1, as the first example of the CuCN SCP containing the (Me3Pb) fragment, was explored to investigate its catalytic and photo-catalytic activities. The structure of 1 contains two chemically identical but crystallographically different [Cu2(CN)3?Me3Pb?qox]2 units with four Cu(I) sites assuming distorted TP-3 geometry. Two non-linear chains of equal abundance are formed producing corrugated parallel chains which are connected laterally by quinoxaline creating 2D-layers which are arranged parallel in an (AB?AB?AB)n fashion forming 3D-network. IR, mass, electronic absorption and fluorescence spectra are also investigated. The SCP 1 is diamagnetic and exhibits good catalytic and photo-catalytic activities for the degradation of methylene blue (MB). The reaction is first order with respect to MB dye. The irradiation of the reaction with UV-light enhanced the rate of MB mineralization. The efficiency of recycled the 1 and the mechanism of degradation of MB dye were investigated. PMID:25124847

Etaiw, Safaa El-din H; Abdou, Safaa N

2015-01-25

226

Porous coordination polymers as novel sorption materials for heat transformation processes.  

PubMed

Porous coordination polymers (PCPs)/metal-organic frameworks (MOFs) are inorganic-organic hybrid materials with a permanent three-dimensional porous metal-ligand network. PCPs or MOFs are inorganic-organic analogs of zeolites in terms of porosity and reversible guest exchange properties. Microporous water-stable PCPs with high water uptake capacity are gaining attention for low temperature heat transformation applications in thermally driven adsorption chillers (TDCs) or adsorption heat pumps (AHPs). TDCs or AHPs are an alternative to traditional air conditioners or heat pumps operating on electricity or fossil fuels. By using solar or waste heat as the operating energy TDCs or AHPs can significantly help to minimize primary energy consumption and greenhouse gas emissions generated by industrial or domestic heating and cooling processes. TDCs and AHPs are based on the evaporation and consecutive adsorption of coolant liquids, preferably water, under specific conditions. The process is driven and controlled by the microporosity and hydrophilicity of the employed sorption material. Here we summarize the current investigations, developments and possibilities of PCPs/MOFs for use in low-temperature heat transformation applications as alternative materials for the traditional inorganic porous substances like silica gel, aluminophosphates or zeolites. PMID:23945102

Janiak, Christoph; Henninger, Stefan K

2013-01-01

227

Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy.  

PubMed

Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes and shapes, high drug loadings, ease of surface modification and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48 ± 3 wt% cisplatin prodrug and 45 ± 5 wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4 ± 2.9 and 12.0 ± 3.9 h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumour xenograft models evaluated, including CT26 colon cancer, H460 lung cancer and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared with free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumour activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy. PMID:24964370

Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

2014-01-01

228

Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy  

NASA Astrophysics Data System (ADS)

Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes and shapes, high drug loadings, ease of surface modification and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3?wt% cisplatin prodrug and 45±5?wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9?h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumour xenograft models evaluated, including CT26 colon cancer, H460 lung cancer and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared with free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumour activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy.

Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

2014-06-01

229

Spectroscopic properties and the catalytic activity of new organo-lead supramolecular coordination polymer containing quinoxaline  

NASA Astrophysics Data System (ADS)

The 3D-supramolecular coordination polymer (SCP) 3?[ Cu2(CN)3(Me3Pb)(qox)], 1, as the first example of the CuCN SCP containing the (Me3Pb) fragment, was explored to investigate its catalytic and photo-catalytic activities. The structure of 1 contains two chemically identical but crystallographically different [Cu2(CN)3?Me3Pb?qox]2 units with four Cu(I) sites assuming distorted TP-3 geometry. Two non-linear chains of equal abundance are formed producing corrugated parallel chains which are connected laterally by quinoxaline creating 2D-layers which are arranged parallel in an (AB⋯AB⋯AB)n fashion forming 3D-network. IR, mass, electronic absorption and fluorescence spectra are also investigated. The SCP 1 is diamagnetic and exhibits good catalytic and photo-catalytic activities for the degradation of methylene blue (MB). The reaction is first order with respect to MB dye. The irradiation of the reaction with UV-light enhanced the rate of MB mineralization. The efficiency of recycled the 1 and the mechanism of degradation of MB dye were investigated.

Etaiw, Safaa El-din H.; Abdou, Safaa N.

2015-01-01

230

Porous coordination polymers with ubiquitous and biocompatible metals and a neutral bridging ligand  

PubMed Central

The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions. The three-dimensional magnesium(II) and calcium(II) PCPs synthesized using such a neutral ligand are stable and show selective adsorption and separation of carbon dioxide over methane at ambient temperature. This synthetic approach allows the structural diversification of Group II magnesium(II) and calcium(II) PCPs. PMID:25592677

Noro, Shin-ichiro; Mizutani, Junya; Hijikata, Yuh; Matsuda, Ryotaro; Sato, Hiroshi; Kitagawa, Susumu; Sugimoto, Kunihisa; Inubushi, Yasutaka; Kubo, Kazuya; Nakamura, Takayoshi

2015-01-01

231

Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy  

PubMed Central

Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes, and shapes; high drug loadings; ease of surface modification; and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3 wt% cisplatin prodrug and 45±5 wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9 h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumor xenograft models evaluated, including CT26 colon cancer, H460 lung cancer, and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared to free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumor activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy. PMID:24964370

Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

2014-01-01

232

Solvothermal synthesis of four polyoxometalate-based coordination polymers including diverse Ag(I)···? interactions.  

PubMed

Four 3D POM-based silver coordination polymers, namely, [Ag17(ptz)11(PW12O40)2]n (1), [Ag17(ptz)11(PMo12O40)2]n (2), [Ag12(ptz)6(CN)2(SiW12O40)]n (3), and [Ag19(ptz)8(H2ptz)(H3ptz)(AgP5W30O110)·7H2O]n (4), have been obtained by solvothermal reaction of AgNO3 and 5-phenyl-1H-tetrazole (Hptz) ligand in the presence of four types of polyoxometalates. Structural analysis shows that four types of Ag(I)···? interactions, m-?(1), m/p-?(2), o/m-?(2), and o/m/p-?(3), were observed in compounds 1-4, depending on the polyoxometalates used. The in situ generated CN(-) ion in compound 3 shows unprecedented mixed ? and ? bonding modes, similar to the C2(2-) ion in well-studied silver acetylides. For 4, the Na(+) ion in the Preyssler heteropolyoxoanion, [NaP5W30O110](14-), was exchanged by Ag(I) under solvothermal conditions, generating a novel [AgP5W30O110](14-) anion. In addition, the photoluminescence behavior of 1-4 was also investigated. PMID:24392969

Liang, Min-Xia; Ruan, Chan-Zi; Sun, Di; Kong, Xiang-Jian; Ren, Yan-Ping; Long, La-Sheng; Huang, Rong-Bin; Zheng, Lan-Sun

2014-01-21

233

Structural variation in Zn(II) coordination polymers built with a semi-rigid tetracarboxylate and different pyridine linkers: synthesis and selective CO2 adsorption studies.  

PubMed

In an effort towards the rational design of porous MOFs with a functionalized channel surface, 3,3',5,5'-tetracarboxydiphenylmethane (H4L1) has been used in combination with two different bipyridine ligands of similar lengths as linkers, and Zn(II) ions as nodes. Under solvothermal conditions, two Zn(II) coordination polymers, {[Zn(H2L1)(L2)] · DMF · 2H2O}n (1) and {[Zn2(L1)(L3)(DMF)2] · DMF · 4H2O}n (2) (DMF = dimethyl formamide, L2 = 3,6-di-pyridin-4-yl-[1,2,4,5]tetrazine, L3 = 4,4'-bispyridylphenyl) are formed in moderate yields. The obvious kink in the central methylene spacer of H4L1 induces either C2v or Cs symmetry in the ligand, allowing different architectures in the resulting frameworks. Single crystal X-ray analysis shows that compound 1 is a one-dimensional (1D) double chain architecture with rhombus voids, linked by Zn2(CO2)4 paddle-wheel secondary building units (SBUs). The tetrazine and pyridine moieties of the co-ligand and free carboxylic acid groups are lined along the voids of the framework. Compound 2, on the other hand, crystallizes as an infinite two-dimensional corrugated sheet structure, where individual sheets are stacked in--ABAB--patterns along the crystallographic b-axis. Thermogravimetric analysis (TGA) and variable temperature powder X-ray diffraction (VTPXRD) studies reveal high thermal stability for 1 but 2 collapses soon after desolvation. The desolvated framework 1' shows selective CO2 adsorption over N2, H2, and CH4 at 273 K, with an isosteric heat of CO2 adsorption of 21.3 kJ mol(-1), suggesting an interaction of the CO2 molecules with the channel walls. PMID:24522488

Sen, Susan; Neogi, Subhadip; Aijaz, Arshad; Xu, Qiang; Bharadwaj, Parimal K

2014-04-28

234

Highly effective heterogeneous chemosensors of luminescent silica@coordination polymer core-shell micro-structures for metal ion sensing  

PubMed Central

Heterogeneous solid sensors are regarded as promising next-generation sensor due to their excellent chemical stability, low contamination, and excellent recyclability, despite their low sensitivity and weak signal. The dispersity and signals specifically from the exterior of solid sensors are critical aspects which define the sensing sensitivity and selectivity. A novel strategy for the preparation of ideal heterogeneous sensors based upon luminescent lanthanide coordination polymers (LnCP) has been demonstrated. Ideal heterogeneous sensors are systematically achieved by producing the sensors in small, uniform, and thin core-shell particles (silica@LnCP, Ln = Eu, Tb). Eventually, we found that the extremely small amount of well-structured silica@LnCP microsphere, less than ca. 1/400 compared to the amount of several known coordination polymer-based sensors, was sufficient to achieve a reliable Cu2+ sensing with even much greater sensitivity (ca. 550% improvement). PMID:25269855

Cho, Won; Lee, Hee Jung; Choi, Sora; Kim, Yoona; Oh, Moonhyun

2014-01-01

235

Highly effective heterogeneous chemosensors of luminescent silica@coordination polymer core-shell micro-structures for metal ion sensing.  

PubMed

Heterogeneous solid sensors are regarded as promising next-generation sensor due to their excellent chemical stability, low contamination, and excellent recyclability, despite their low sensitivity and weak signal. The dispersity and signals specifically from the exterior of solid sensors are critical aspects which define the sensing sensitivity and selectivity. A novel strategy for the preparation of ideal heterogeneous sensors based upon luminescent lanthanide coordination polymers (LnCP) has been demonstrated. Ideal heterogeneous sensors are systematically achieved by producing the sensors in small, uniform, and thin core-shell particles (silica@LnCP, Ln = Eu, Tb). Eventually, we found that the extremely small amount of well-structured silica@LnCP microsphere, less than ca. 1/400 compared to the amount of several known coordination polymer-based sensors, was sufficient to achieve a reliable Cu(2+) sensing with even much greater sensitivity (ca. 550% improvement). PMID:25269855

Cho, Won; Lee, Hee Jung; Choi, Sora; Kim, Yoona; Oh, Moonhyun

2014-01-01

236

Highly effective heterogeneous chemosensors of luminescent silica@coordination polymer core-shell micro-structures for metal ion sensing  

NASA Astrophysics Data System (ADS)

Heterogeneous solid sensors are regarded as promising next-generation sensor due to their excellent chemical stability, low contamination, and excellent recyclability, despite their low sensitivity and weak signal. The dispersity and signals specifically from the exterior of solid sensors are critical aspects which define the sensing sensitivity and selectivity. A novel strategy for the preparation of ideal heterogeneous sensors based upon luminescent lanthanide coordination polymers (LnCP) has been demonstrated. Ideal heterogeneous sensors are systematically achieved by producing the sensors in small, uniform, and thin core-shell particles (silica@LnCP, Ln = Eu, Tb). Eventually, we found that the extremely small amount of well-structured silica@LnCP microsphere, less than ca. 1/400 compared to the amount of several known coordination polymer-based sensors, was sufficient to achieve a reliable Cu2+ sensing with even much greater sensitivity (ca. 550% improvement).

Cho, Won; Lee, Hee Jung; Choi, Sora; Kim, Yoona; Oh, Moonhyun

2014-10-01

237

Syntheses, structures and luminescent properties of a series of 3D lanthanide coordination polymers with tripodal semirigid ligand  

SciTech Connect

Reactions of the tripodal bridging ligand 5-(4-carboxy-phenoxy)-isophthalic acid (abbreviated as H{sub 3}cpia) with lanthanide salts lead to the formation of a family of different coordination polymers, that is, [Ln(cpia)(H{sub 2}O){sub 2}]{sub n}.nH{sub 2}O (Ln=Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Dy (7), Er (8), Tm (9) and Y (10)) in the presence of formic acid or diethylamine, which are characterized by elemental analysis, IR spectrum, thermogravimetric analysis (TGA), XRPD spectrum and single-crystal X-ray diffraction. Compounds 1-10 are isostructural and exhibit three-dimensional microporous frameworks. Furthermore, the photoluminescent properties of 4, 5 and 7 have been studied in detail. -- Graphical abstract: Reactions of the tripodal bridging ligand (H{sub 3}cpia) with lanthanide ions lead to the formation of a series of coordination polymers in the presence of formic acid or diethylamine. Display Omitted Research Highlights: {yields} Ten new lanthanides-based coordination polymers (1-10) have been synthesized. {yields} 1-10 exhibit 3D (4,8)-connected fluorite topology networks with 1D channel parallel to the b-axis. {yields} Compounds 4, 5 and 7 exhibit characteristic luminescence of Sm{sup 3+}, Eu{sup 3+} and Dy{sup 3+} ions, respectively.

Qin Junsheng [Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Department of Applied Chemistry, Jilin Institute of Chemical Technology, Jilin 132022 (China); Du Dongying; Chen Lei [Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Sun Xiuyun [Department of Applied Chemistry, Jilin Institute of Chemical Technology, Jilin 132022 (China); Lan Yaqian [Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China); Su Zhongmin, E-mail: zmsu@nenu.edu.c [Institute of Functional Material Chemistry, Key Lab of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024 (China)

2011-02-15

238

Wide spectral range nonlinear optical crystals of one-dimensional coordination solids [Et4N][Cd(SCN)3] and [Et4N][Cd(SeCN)3] and the general design criteria for [R4N][Cd(XCN)3] (Where R = Alkyl and X = S, Se, Te) as NLO crystals.  

PubMed

We report herein two new nonlinear optical (NLO) crystals, [Et4N][Cd(XCN)3], where X = S (1) and Se (2), that are transparent from 220 to 3300 nm, covering the entire near-ultraviolet, the visible, and the near-infrared spectral regions and giving rise to a very wide and continuous optical window, which is useful for many frequency conversion applications. Both 1 and 2 exhibit highly efficient second harmonic generation (SHG) as measured via the Kurtz-Perry method. The corresponding [Me4N]+ salts, [Me4N][Cd(XCN)3 where X = S (3) and Se (4), show no SHG effects. All four structures adopt noncentrosymmetric space groups (Cmc2(1) for 1 and 2 and Pna2(1) for 3 and presumably 4) and are based on one-dimensional anionic [Cd(XCN)3-] infinity zigzag chains. However, a detailed analysis of the structures of [R4N][Cd(XCN)3], where R = Et, Me and X = S, Se revealed that the difference in the second-order nonlinear responses of the Et4N+ salts (1 and 2) and the Me4N+ salts (3 and 4) is attributable to the relative alignment of the [Cd(XCN)3-] infinity zigzag chains, being parallel in the crystals of 1 and 2 but antiparallel in the crystals of 3 and 4. Also reported, for the first time, are the synthesis and crystal structure of [Et4N][Cd(SeCN)3] (2). Compound 2 crystallizes in an orthorhombic unit cell of Cmc21 space group symmetry with lattice parameters of 9.938(1) A, 16.868(2) A, 11.054(1) A, and Z = 4. Other issues related to the molecular and crystal engineering of this class of NLO materials are also discussed. PMID:11428105

Zhang, H; Zelmon, D E; Price, G E; Teo, B K

2000-05-01

239

Theory of Spin Motive Force in One-Dimensional Antiferromagnetic Domain Wall  

NASA Astrophysics Data System (ADS)

We present the theory of the spin motive force in antiferromagnets. We consider a one-dimensional antiferromagnetic domain wall strongly coupled with conduction electrons via an exchange interaction. We carry out a unitary transformation that rotates the spin coordinate system of the conduction electron locally, so that the quantization axis is in the direction of the localized spin. By numerically solving the time dependent Schrödinger equation, we clearly demonstrate that the spin motive force acts on the conduction electron. The result suggests that there is no distinction between antiferromagnets and ferromagnets from the viewpoint of the basic phenomenon relevant to spintronics.

Okabayashi, Akira; Morinari, Takao

2015-03-01

240

Phase Space Reduction of the One-Dimensional Fokker-Planck (Kramers) Equation  

NASA Astrophysics Data System (ADS)

A point-like particle of finite mass m, moving in a one-dimensional viscous environment and biased by a spatially dependent force, is considered. We present a rigorous mapping of the 1D Fokker-Planck (Kramers) equation, which determines evolution of the particle density in phase space, onto the spatial coordinate x. The result is the Smoluchowski equation, valid in the overdamped limit, m?0, with a series of corrections expanded in powers of m/ ?, ? denotes the friction coefficient. The corrections are determined unambiguously within the recurrence mapping procedure. The method and the results are interpreted on the simplest model with no field and on the damped harmonic oscillator.

Kalinay, Pavol; Percus, Jerome K.

2012-09-01

241

Quantum and Thermal Effects of Dark Solitons in a One-Dimensional Bose Gas  

SciTech Connect

We numerically study the imprinting and dynamics of dark solitons in a bosonic atomic gas in a tightly confined one-dimensional harmonic trap both with and without an optical lattice. Quantum and thermal fluctuations are synthesized within the truncated Wigner approximation in the quasicondensate description. We track the soliton coordinates and calculate position and velocity uncertainties. We find that the phase fluctuations lower the classically predicted soliton speed and seed instabilities. Individual runs show interactions of solitons with sound waves, splitting, and disappearing solitons.

Martin, A. D.; Ruostekoski, J. [School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2010-05-14

242

Quasi-one-dimensional optical lattices for soliton manipulation.  

PubMed

Based on angular spectrum engineering, we report the generation of optical lattices whose two-dimensional transverse nondiffracting pattern can be reduced to a quasi-one-dimensional intensity structure formed by either a single or multiple parallel channels. Remarkably, many features for each channel such as its maximum intensity, modulation, width, or separation among channels, can be controlled and modified in order to meet the requirements of particular applications. In particular, we demonstrate that these lattices can provide useful schemes for soliton routing and steering. We demonstrate the existence domain of ground-state solitons for the single quasi-one-dimensional lattice, and we show that these nondiffracting beams allow "push and pull" dynamics among the neighbor solitons propagated along the nondiffracting channels generated. PMID:25490515

Lopez-Aguayo, Servando; Ruelas-Valdez, Cesar; Perez-Garcia, Benjamin; Ortiz-Ambriz, Antonio; Hernandez-Aranda, Raul I; Gutiérrez-Vega, Julio C

2014-11-15

243

Chemically Reacting One-Dimensional Gas-Particle Flows  

NASA Technical Reports Server (NTRS)

The governing equations for the one-dimensional flow of a gas-particle system are discussed. Gas-particle effects are coupled via the system momentum and energy equations with the gas assumed to be chemically frozen or in chemical equilibrium. A computer code for calculating the one-dimensional flow of a gas-particle system is discussed and a user's input guide presented. The computer code provides for the expansion of the gas-particle system from a specified starting velocity and nozzle inlet geometry. Though general in nature, the final output of the code is a startline for initiating the solution of a supersonic gas-particle system in rocket nozzles. The startline includes gasdynamic data defining gaseous startline points from the nozzle centerline to the nozzle wall and particle properties at points along the gaseous startline.

Tevepaugh, J. A.; Penny, M. M.

1975-01-01

244

Assessing the inherent uncertainty of one-dimensional diffusions  

NASA Astrophysics Data System (ADS)

In this paper we assess the inherent uncertainty of one-dimensional diffusion processes via a stochasticity classification which provides an à la Mandelbrot categorization into five states of uncertainty: infra-mild, mild, borderline, wild, and ultra-wild. Two settings are considered. (i) Stopped diffusions: the diffusion initiates from a high level and is stopped once it first reaches a low level; in this setting we analyze the inherent uncertainty of the diffusion's maximal exceedance above its initial high level. (ii) Stationary diffusions: the diffusion is in dynamical statistical equilibrium; in this setting we analyze the inherent uncertainty of the diffusion's equilibrium level. In both settings general closed-form analytic results are established, and their application is exemplified by stock prices in the stopped-diffusions setting, and by interest rates in the stationary-diffusions setting. These results provide a highly implementable decision-making tool for the classification of uncertainty in the context of one-dimensional diffusions.

Eliazar, Iddo; Cohen, Morrel H.

2013-01-01

245

Highly efficient stabilisation of meta-ethynylpyridine polymers with amide side chains in water by coordination of rare-earth metals.  

PubMed

An amphiphilic meta-ethynylpyridine polymer with chiral amide side chains was developed. The polymer was prepared by sequential Sonogashira reactions, and the product was soluble in polar and apolar solvents. The additive effects of metal salts on the polymer were examined in water and aqueous EtOH on the basis of UV-vis and CD spectra. The enhancement of the positive Cotton effect and hypochromism around 360 nm occurred by the addition of various metal salts, indicating the coordination of the cations to the amide side chains of the polymer to stabilise the helical structure. Among them, rare-earth metal salts, especially Sc(OTf)3 showed more efficient additive effects probably because of its strong coordination ability even in water. Positive cooperativity was observed for the coordination of Sc(OTf)3 to the polymer in aqueous EtOH. PMID:25473810

Makida, Hiroki; Abe, Hajime; Inouye, Masahiko

2015-02-14

246

Spin waves in a one-dimensional spinor Bose gas  

Microsoft Academic Search

We study a one-dimensional (iso)spin 1\\/2 Bose gas with repulsive\\u000adelta-function interaction by the Bethe Ansatz method and discuss the\\u000aexcitations above the polarized ground state. In addition to phonons the system\\u000afeatures spin waves with a quadratic dispersion. We compute analytically and\\u000anumerically the effective mass of the spin wave and show that the spin\\u000atransport is greatly suppressed

J. N. Fuchs; D. M. Gangardt; T. Keilmann; G. V. Shlyapnikov

2005-01-01

247

Cloud pumping in a one-dimensional photochemical model  

NASA Technical Reports Server (NTRS)

Cloud pumping data based on tropical maritime updraft statistics are incorporated in a one-dimensional steady-state eddy diffusive photochemical model of the troposphere. It is suggested that regions with weaker convection, such as the midlatitudes, may also experience substantial effects from cloud pumping. The direct effects of cloud pumping on CO were found to be more significant than implied by sensitivity studies. The (CH3)2S profile computed with cloud pumping agrees well with previous data.

Costen, Robert C.; Tennille, Geoffrey M.; Levine, Joel S.

1988-01-01

248

Vertical multijunction solar-cell one-dimensional analysis  

Microsoft Academic Search

The vertical multijunction solar cell is a photovoltaic device which may allow conversion efficiencies higher than conventional planar devices. A one-dimensional model of the device is presented here which allows a simple and straightforward analysis of device performance to be conducted. The analysis covers the derivation of device short-circuit current, saturation current, open-circuit voltage, and maximum power as a function

AVRAHAM GOVER; PAUL STELLA

1974-01-01

249

Growth of one-dimensional single-crystalline hydroxyapatite nanorods  

NASA Astrophysics Data System (ADS)

A facile, effective and template/surfactant-free hydrothermal route in the presence of sodium bicarbonate was developed to synthesize highly uniform single-crystalline hydroxyapatite (HA) nanorods with the lengths of several hundred nanometers and aspect ratio up to ˜20. One dimensional (1-D) growth and aspect ratio could be controlled by hydrothermal reaction time and temperature. The longitudinal axis, also the growth direction of the nanorods, is parallel to the [001] direction of HA hexagonal crystal structure.

Ren, Fuzeng; Ding, Yonghui; Ge, Xiang; Lu, Xiong; Wang, Kefeng; Leng, Yang

2012-06-01

250

Fabry-Pérot resonances in one-dimensional plasmonic nanostructures.  

PubMed

We study the near-field optical behavior of Fabry-Pérot resonances in thin metal nanowires, also referred to as quasi one-dimensional plasmonic nanoantennas. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection phase of the guided surface plasmon polariton with superb accuracy. The combined symmetry breaking effects of oblique illumination and retardation allow the excitation of dipole forbidden, even order resonances. All measurements are supported by rigorous simulations of the experimental situation. PMID:19472987

Dorfmüller, Jens; Vogelgesang, Ralf; Weitz, R Thomas; Rockstuhl, Carsten; Etrich, Christoph; Pertsch, Thomas; Lederer, Falk; Kern, Klaus

2009-06-01

251

Organized one dimensional nanomaterials: From preparations to applications  

Microsoft Academic Search

This thesis is mainly concerned with the development of organized one dimensional (1D) nanomaterials and their applications. We have synthesized Ag2S, Cu2S nanowires, Fe2O3 nanobelt and nanowire arrays and ZnO nanobelt arrays from corresponding metal substrate respectively via gas solid reaction methods under different growth conditions. The effect of various parameters including temperature, reaction time, composition of gas, surface pre-oxidation,

Xiaogang Wen

2005-01-01

252

SIMPLE ONE-DIMENSIONAL CALCULATION OF HALL THRUSTER FLOWFIELDS  

Microsoft Academic Search

Low-power Hall thruster flowfields were calculated using a simple one-dimensional model to understand plasma characteristics and ion acceleration processes and to predict thruster performance. The influences of magnetic field strength and acceleration channel length were mainly examined. The model includes first ionization by direct electron-neutral collisions, electron-neutral elastic collisions, Bohm diffusion (anomalous diffusion); channel wall losses of ion flux and

Hirokazu Tahar; Takashi Fujioka; Atsushi Shirasaki; Takao Yoshikawa

253

A new one-dimensional variable frequency photonic crystals  

E-print Network

In this paper, we have firstly proposed a new one-dimensional variable frequency photonic crystals (VFPCs). We have calculated the transmissivity and the electronic field distribution of VFPCs and compare them with the conventional PCs, and obtained some new results, which should be help to design a new type optical devices, and the two-dimensional and three-dimensional VFPCs can be studied further.

Wu, Xiang-Yao; Liu, Xiao-Jing; Li, Hong; Chen, Wan-Jin

2015-01-01

254

One-dimensional Germanium Nanowires for Future Electronics  

Microsoft Academic Search

Field- and quantum-effect nanoelectronic devices built on one-dimensional (1-D) chemically synthesized nanostructures are likely among those immediate “successors” of the contemporary top–down silicon CMOS technology for future computing, preserving the spirit of Moore’s Law in the post-CMOS era. The nanotechnology-embedded chip technology would emerge in the foreseeable future. However, there exists a large gap between scientific research and semiconductor electronics.

B. Yu; X. H. Sun; G. A. Calebotta; G. R. Dholakia; M. Meyyappan

2006-01-01

255

Thermalization in a one-dimensional integrable system  

SciTech Connect

We present numerical results demonstrating the possibility of thermalization of single-particle observables in a one-dimensional system, which is integrable in both the quantum and classical (mean-field) descriptions (a quasicondensate of ultracold, weakly interacting bosonic atoms are studied as a definite example). We find that certain initial conditions admit the relaxation of single-particle observables to the equilibrium state reasonably close to that corresponding to the Bose-Einstein thermal distribution of Bogoliubov quasiparticles.

Grisins, Pjotrs [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, A-1020 Vienna (Austria); Mazets, Igor E. [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, A-1020 Vienna (Austria); Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation)

2011-11-15

256

Quasi-one-dimensional magnons in an intermetallic marcasite  

SciTech Connect

We present inelastic neutron scattering measurements and rst principles calculations examining the intermetallic marcasite CrSb2. The observed spin wave dispersion implies that the magnetic interactions are strongly one-dimensional with antiferromagnetic chains parallel to the crystalline c-axis. Such low-dimensional excitations are unexpected in a semiconducting intermetallic system. Moreover this material may be further interesting in that the magnetic anisotropy may enhance thermoelectric properties along particular crystallographic directions.

Stone, Matthew B [ORNL; Lumsden, Mark D [ORNL; Nagler, Stephen E [ORNL; Singh, David J [ORNL; Sales, Brian C [ORNL; Mandrus, David [ORNL

2012-01-01

257

One-dimensional random walk with phase transition  

SciTech Connect

A random walk on a one-dimensional lattice is considered. The walk is asymmetric but with different asymmetry on the right and left halves of the line. As the parameter space describing the two asymmetries is covered, several qualitatively different distributions result: limiting distribution, unimodal diffusion and biomodal diffusion. The corresponding parameter space phase boundaries are obtained, as well as the precise form of the distributions.

Percus, O.E.; Percus, J.K.

1981-06-01

258

One-dimensional random walk with phase transition  

SciTech Connect

We consider a random walk on a one-dimensional lattice. The walk is asymmetric but with different asymmetry on the right and left halves of the line. As the parameter space describing the two asymmetries is covered, several qualitatively different distributions result: limiting distribution, unimodal diffusion and bimodal diffusion. The corresponding parameter space phase boundaries are obtained, as well as the precise form of the distributions.

Percus, O.E.; Percus, J.K.

1981-06-01

259

One-Dimensional Traffic Flow Models: Theory and Computer Simulations  

Microsoft Academic Search

Theoretical advances in the study of non-equilibrium phenomena are briefly\\u000areviewed with emphasis on steady state properties of one-dimensional driven\\u000alattice gases. The presentation is focused on the totally asymmetric\\u000asimple-exclusion process (TASEP) with open boundary conditions: particles are\\u000ainjected at the left end with rate alpha and removed at the right end with rate\\u000abeta. Depending on the values

J. G. Brankov; N. C. Pesheva; N. Zh

2008-01-01

260

One-Dimensional Traffic Flow Models: Theory and Computer Simulations  

Microsoft Academic Search

Theoretical advances in the study of non-equilibrium phenomena are briefly reviewed with emphasis on steady state properties of one-dimensional driven lattice gases. The presentation is focused on the totally asymmetric simple-exclusion process (TASEP) with open boundary conditions: particles are injected at the left end with rate alpha and removed at the right end with rate beta. Depending on the values

J. G. Brankov; N. C. Pesheva; N. Zh. Bunzarova

2008-01-01

261

On numerical modeling of one-dimensional geothermal histories  

USGS Publications Warehouse

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

Haugerud, R.A.

1989-01-01

262

Anomalous velocity fluctuation in one-dimensional defect turbulence  

NASA Astrophysics Data System (ADS)

In this paper various eccentric hole dynamics are presented in defect turbulence of the one-dimensional complex Ginzburg-Landau equation. Each hole shows coherent particlelike motion with nonconstant velocity. On the other hand, successive hole velocities without discriminating each hole exhibit anomalous intermittent motions being subject to multi-time-scale non-Gaussian statistics. An alternate non-Markov stochastic differential equation is proposed, by which all these observed statistical properties can be described successfully.

Uchiyama, Yusuke; Kadoya, Takanori; Konno, Hidetoshi

2015-02-01

263

One-dimensional zinc oxide nanomaterials synthesis and photovoltaic applications  

Microsoft Academic Search

As humanly engineered materials systems approach the atomic scale, top-down manufacturing approaches breakdown and following nature's example, bottom-up or self-assembly methods have the potential to emerge as the dominant paradigm. Synthesis of one-dimensional nanomaterials takes advantage of such self-assembly manufacturing techniques, but until now most efforts have relied on high temperature vapor phase schemes which are limited in scalability and

Benjamin A. Weintraub

2010-01-01

264

Series of mixed uranyl-lanthanide (Ce, Nd) organic coordination polymers with aromatic polycarboxylates linkers.  

PubMed

Three series of mixed uranyl-lanthanide (Ce or Nd) carboxylate coordination polymers have been successfully synthesized by means of a hydrothermal route using either conventional or microwave heating methods. These compounds have been prepared from mixtures of uranyl nitrate, lanthanide nitrate together with phthalic acid (1,2), pyromellitic acid (3,4), or mellitic acid (5,6) in aqueous solution. The X-ray diffraction (XRD) single-crystal revealed that the phthalate complex (UO(2))(4)O(2)Ln(H(2)O)(7)(1,2-bdc)(4)·NH(4)·xH(2)O (Ln = Ce(1), Nd(2); x = 1 for 1, x = 0 for 2), is based on the connection of tetranuclear uranyl-centered building blocks linked to discrete monomeric units LnO(2)(H(2)O)(7) via the organic species to generate infinite chains, intercalated by free ammonium cations. The pyromellitate phase (UO(2))(3)Ln(2)(H(2)O)(12)(btec)(3)·5H(2)O (Ce(3), Nd(4)) contains layers of monomeric uranyl-centered hexagonal and pentagonal bipyramids linked via the carboxylate arms of the organic molecules. The three-dimensionality of the structure is ensured by the connection of remaining free carboxylate groups with isolated monomeric units LnO(2)(H(2)O)(7). The network of the third series (UO(2))(2)(OH)Ln(H(2)O)(7)(mel)·5H(2)O (Ce(5), Nd(6)) is built up from dinuclear uranyl units forming layers through connection with the mellitate ligands, which are further linked to each other through discrete monomers LnO(3)(H(2)O)(6). The thermal decomposition of the various coordination complexes led to the formation of mixed uranium-lanthanide oxide, with the fluorite-type structure at 1500 °C (for 1, 2) or 1400 °C for 3-6. Expected U/Ln ratio from the crystal structures were observed for compounds 1-6. PMID:22931214

Mihalcea, Ionut; Volkringer, Christophe; Henry, Natacha; Loiseau, Thierry

2012-09-17

265

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers  

NASA Astrophysics Data System (ADS)

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The technical cooperation (TC) programme helps Member States to realize their development priorities through the application of appropriate radiation technology. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. The IAEA extends cooperation to well-known international conferences dealing with radiation technology to facilitate participation of talented scientists from developing MS and building collaborations. The IAEA published technical documents, covering the findings of thematic technical meetings (TM) and coordinated research projects have been an important source of valuable practical information.

Haji-Saeid, M.; Sampa, M. H.; Ramamoorthy, N.; Güven, O.; Chmielewski, A. G.

2007-12-01

266

Synthesis of nanostructured materials by using metal-cyanide coordination polymers and their lithium storage properties  

NASA Astrophysics Data System (ADS)

Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices.Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices. Electronic supplementary information (ESI) available: Detailed experimental procedures and supplementary figures. See DOI: 10.1039/c3nr03289b

Nie, Ping; Shen, Laifa; Luo, Haifeng; Li, Hongsen; Xu, Guiyin; Zhang, Xiaogang

2013-10-01

267

Thermodynamically metastable thiocyanato coordination polymer that shows slow relaxations of the magnetization.  

PubMed

Reaction of cobalt thiocyanate with 4-acetylpyridine leads to the formation of [Co(NCS)2(4-acetylpyridine)2]n (3/I). In its crystal structure the Co cations are connected by pairs of ?-1,3-bridging thiocyanato ligands into dimers that are further connected into layers by single anionic ligands. DTA-TG measurements of Co(NCS)2(4-acetyl-pyridine)4 (1) led to the formation of 3/I. In contrast, when the hydrate Co(NCS)2(4-acetyl-pyridine)2(H2O)2 (2) is decomposed, a mixture of 3/I and a thermodynamically metastable form 3/II is obtained. Further investigations reveal that thermal annealing of 2 leads to the formation of 3/II, that contains only traces of the stable form 3/I. DSC and temperature dependent X-ray powder diffraction (XRPD) measurements prove that 3/II transforms into 3/I on heating. The crystal structure of 3/II was determined ab initio from XRPD data. In its crystal structure the Co cations are linked by pairs of bridging thiocyanato anions into a 1D coordination polymer, and thus, 3/II is an isomer of 3/I. Magnetic measurements disclose that the stable form 3/I only shows paramagnetism without any magnetic anomaly down to 2 K. In contrast, the metastable form 3/II shows ferromagnetic behavior. The phase transition into ordered state at Tc = 3.8 K was confirmed by specific heat measurements. Alternating current susceptibility measurements show frequency dependent maxima in ?' and ??, which is indicative for a slow relaxation of the magnetization. PMID:25741770

Werner, Julia; Rams, Micha?; Tomkowicz, Zbigniew; Run?evski, Tom?e; Dinnebier, Robert E; Suckert, Stefan; Näther, Christian

2015-03-16

268

Aromatic carboxylate effect on dimensionality of three bis(benzimidazole)-based cobalt(II) coordination polymers: Syntheses, structures and properties  

NASA Astrophysics Data System (ADS)

Three new metal-organic coordination polymers [Co(4-bbc)2(bbbm)] (1), [Co(3,5-pdc)(bbbm)]·2H2O (2) and [Co(1,4-ndc)(bbbm)] (3) (4-Hbbc=4-bromobenzoic acid, 3,5-H2pdc=3,5-pyridinedicarboxylic acid, 1,4-H2ndc=1,4-naphthalenedicarboxylic acid and bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole) were hydrothermally synthesized and structurally characterized. Polymer 1 is a 1D chain formed by the bbbm ligands and CoII ions. Polymer 2 exhibits a 2D network with a (3·4·5)(32·4·5·62·74) topology. Polymer 3 possesses a 3D three-fold interpenetrating framework. The versatile structures of title polymers indicate that the aromatic carboxylates have an important influence on the dimensionality of 1-3. Moreover, the thermal stability, electrochemical and luminescent properties of 1-3 were investigated.

Zhang, Ju-Wen; Gong, Chun-Hua; Hou, Li-Li; Tian, Ai-Xiang; Wang, Xiu-Li

2013-09-01

269

Control of water molecule aggregations in copper 1,4-cyclohexanedicarboxylate coordination polymers containing pyridyl-piperazine type ligands  

NASA Astrophysics Data System (ADS)

A series of layered divalent copper coordination polymers containing 1,4-cyclohexanedicarboxylate and long-spanning pyridyl-piperazine type ligands exhibits greatly different co-crystallized water molecule aggregations depending on the specific ligands used. Both [Cu(t-14cdc)(4-bpmp)]n (1, t-14cdc = trans-1,4-cyclohexanedicarboxylate, 4-bpmp = bis(4-pyridylmethyl)piperazine) and {[Cu(t-14cdc)(4-bpfp)(H2O)2]·6H2O}n (2, 4-bpfp = bis(4-pyridylformyl)piperazine) possess 2D (4,4) coordination polymer grids. However 1 lacks any co-crystallized water and has pinched grid apertures, while 2 manifests infinite water tapes with T6(2)4(2) classification and rectangular grid apertures. {[Cu2(c-14cdc)2(4-bpmp)]·2H2O}n (3, c-14cdc = cis-1,4-cyclohexanedicarboxylate) has [Cu2(c-14cdc)]2 ribbons with paddlewheel dimeric units linked into 2D slabs by 4-bpmp tethers, along with isolated water molecule pairs. In contrast, {[Cu2(c-14cdc)2(4-bpfp)]·10H2O}n (4) shows a very similar underlying coordination polymer topology but entrains unique decameric water molecule clusters. The minor product {[Cu2(c-14cdcH)2(t-1,4-cdc)(4-bpfp)2(H2O)2]·2H2O}n (5) was isolated along with 4; this compound underwent some in situ cis to trans cyclohexane-dicarboxylate ligand isomerization and exhibits a ladder polymer motif.

Qiblawi, Sultan H.; LaDuca, Robert L.

2014-01-01

270

Catalyst-site-controlled coordination polymerization of polar vinyl monomers to highly syndiotactic polymers.  

PubMed

This contribution reports a combined synthetic, kinetic, mechanistic, and theoretical/computational study of the recently discovered catalyst-site-controlled coordination polymerization of polar vinyl monomers [such as methyl methacrylate (MMA) and N,N-dimethylacrylamide (DMAA)] into highly syndiotactic polymers. Among the 12 C(s)-ligated ansa-cyclopentadienyl (Cp)-R(2)E(C,Si)-fluorenyl (Flu) group 4 metallocene catalyst systems examined-which varied in metal center, anion structure, bridging atom and substituents, and ligand substitution pattern-cationic ansa-metallocene ester enolate catalyst 6(+)[B(C(6)F(5))(4)](-), derived from the activation of the precatalyst [Ph(2)C(Cp)(2,7-(t)Bu(2)-Flu)]Zr[OC(O(i)Pr)=CMe(2)](2) with [Ph(3)C][B(C(6)F(5))(4)], stood out as the best catalyst in all aspects of the MMA polymerization at room temperature, including the highest activity (1554 h(-1) TOF), efficiency (98% I*), syndiotacticity (94% rr), and control (predicted number-average molecular weight and 1.14 molecular weight distribution). Kinetic and mechanistic results are consistent with a catalyst-site-controlled, monometallic coordination-addition mechanism, involving fast intramolecular addition within the catalyst-monomer complex leading to the resting eight-membered ester enolate chelate, followed by the rate-limiting ring-opening of the chelate to regenerate the active species. This work has also uncovered several unique features of this polymerization system that are in marked contrast to the propylene polymerization by analogous C(s)-ligated cationic alkyl catalysts: a constant syndiotacticity of PMMA produced over a wide polymerization temperature range (i.e., from 0 degrees C, 94% rr to 25 degrees C, 94% rr to 50 degrees C, 93% rr); insensitivity of its high activity, degree of control, and stereoselectivity to solvent polarity and structure of weakly coordinating anions; and deviation from a pure site-control mechanism at high [MMA]/[catalyst] ratios. Computational results provide theoretical support for the proposed monomer-assisted, catalyst-site epimerization, after an enantiofacial mistake, to a thermodynamically more stable resting state, which accounts for the observed higher than expected [mr] contents based on a pure site-controlled mechanism. DFT calculations rationalize why the Ph(2)C< bridged catalyst 6 exhibits higher stereoselectivity than other catalysts with the Me(2)C< or Me(2)Si< bridge: the bridge rigidity pushes the eta(3)-bound Flu ligand closer to the growing chain and the monomer, thereby increasing DeltaE(stereo) between the competing transition states for the addition of a monomer molecule to the opposite (correct and wrong) enantiofaces of the enolate growing chain. The relative polymerization activity of this catalyst series is shown to correlate with the relative energetics of the back-biting of the penultimate unit and ion-pair formation. PMID:20121281

Zhang, Yuetao; Ning, Yalan; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

2010-03-01

271

Synthesis, structures and properties of two metal-organic coordination polymers derived from manganese(??), thiabendazole and polydentate carboxylic acids.  

PubMed

Two novel binuclear Mn(II) metal-organic coordination complexes [Mn2(TBZ)2(CDC)(C2O4)]n (1), {[Mn2(TBZ)2(BDC)(0.5)(BTC)(H2O)2]·ET}n (2), (where TBZ = thiabendazole, H2CDC = trans-1,4-cyclohexanedicarboxylic acid, H2C2O4 = oxalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid, ET = ethanol, H2BDC = 1,4-benzenedicarboxylate) have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, electrochemical analysis and single crystal X-ray diffraction. The X-ray structure analysis reveals that 1 is s two-dimensional layer and 2 is s one-dimensional chain. In complex 1, it reveals 2-D layers composed of multi-(bidentate) bridging ligands (CDC and C2O4), and in 2, the coordinated BTC ligands adopt a monodentate mode and with BDC ligands adopt alternately chelating Mn1 and Mn2 bridges into 1-D chains. The 3-D structures of the two complexes are stabilized by ?-? stacking interactions and hydrogen bonds. PMID:24317523

Liang, Peng; Xia, Wen-Xiu; Tian, Wei-Man; Yin, Xian-Hong

2013-01-01

272

A copper(I) coordination polymer incorporation the corrosion inhibitor 1H-benzotriazole: poly[?3-benzotriazolato-?(3)N(1):N(2):N(3)-copper(I)].  

PubMed

The title complex, [Cu(C6H4N3)]n, was synthesized by the reaction of cupric nitrate, 1H-benzotriazole (BTAH) and aqueous ammonia under hydrothermal conditions. The asymmetric unit contains three crystallographically independent Cu(I) cations and two 1H-benzotriazolate ligands. Two of the Cu(I) cations, one with a linear two-coordinated geometry and one with a four-coordinated tetrahedral geometry, are located on sites with crystallographically imposed twofold symmetry. The third Cu(I) cation, with a planar three-coordinated geometry, is on a general position. Two Cu(I) cations are doubly bridged by two BTA(-) ligands to afford a noncentrosymmetric planar [Cu2(BTA)2] subunit, and two [Cu2(BTA)2] subunits are arranged in an antiparallel manner to form a centrosymmetric [Cu2(BTA)2]2 secondary building unit (SBU). The SBUs are connected in a crosswise manner via the sharing of four-coordinated Cu(I) cations, Cu-N bonding and bridging by two-coordinate Cu(I) cations, resulting in a one-dimensional chain along the c axis. These one-dimensional chains are further linked by C-H···? and weak van der Waals interactions to form a three-dimensional supramolecular architecture. PMID:24898965

Liu, Jian-Jun; Li, Zuo-Yin; Yuan, Xiong; Wang, Yao; Huang, Chang-Cang

2014-06-01

273

One-dimensional Coulomb problem in Dirac materials  

E-print Network

We investigate the one-dimensional Coulomb potential with application to a class of quasirelativistic systems, so-called Dirac-Weyl materials, described by matrix Hamiltonians. We obtain the exact solution of the shifted and truncated Coulomb problems, with the wavefunctions expressed in terms of special functions (namely Whittaker functions), whilst the energy spectrum must be determined via solutions to transcendental equations. Most notably, there are critical bandgaps below which certain low-lying quantum states are missing in a manifestation of atomic collapse.

C. A. Downing; M. E. Portnoi

2014-11-21

274

Spin waves in a one-dimensional spinor bose gas.  

PubMed

We study a one-dimensional (iso)spin 1/2 Bose gas with repulsive delta-function interaction by the Bethe Ansatz method and discuss the excitations above the polarized ground state. In addition to phonons the system features spin waves with a quadratic dispersion. We compute analytically and numerically the effective mass of the spin wave and show that the spin transport is greatly suppressed in the strong coupling regime, where the isospin-density (or "spin charge") separation is maximal. Using a hydrodynamic approach, we study spin excitations in a harmonically trapped system and discuss prospects for future studies of two-component ultracold atomic gases. PMID:16241701

Fuchs, J N; Gangardt, D M; Keilmann, T; Shlyapnikov, G V

2005-10-01

275

Statistical properties of one-dimensional random lasers.  

PubMed

Statistical properties of a laser based on a one-dimensional disordered superlattice open at one side are studied numerically. The passive normal modes of the system are determined using the Feshbach projection technique. It is found that the mode competition due to the spacial hole burning leads to a saturation of the number of lasing modes with increasing pump rate. It is also responsible for nonmonotonic dependence of intensities of lasing modes as functions of pumping. Computed distributions of spectral spacing and intensity statistics are in qualitative agreement with experimental results. PMID:19257422

Zaitsev, Oleg; Deych, Lev; Shuvayev, Vladimir

2009-01-30

276

One dimensional Brownian motion in hard rods: adiabatic piston problem  

E-print Network

We have investigated the motion characteristics of a movable piston immersed in a one dimensional gas of hard rods by event-oriented molecular dynamics in the absence of thermal noise. Periodic and reflecting boundary conditions are explored. It is shown that the piston undergoes systematic oscillations with decaying amplitudes in short times before it comes to global thermodynamic equilibrium. Moreover, the diffusion of the piston is explored and analytical expressions for its equilibrium mean-squared displacement is obtained. It is shown that MSD of the piston does not differ much from the normal rods despite its mass and length are significantly larger.

M. Ebrahim Foulaadvand; M. Mehdi Shafiee

2014-09-11

277

Waves and instability in a one-dimensional microfluidic array.  

PubMed

Motion in a one-dimensional (1-D) microfluidic array is simulated. Water droplets, dragged by flowing oil, are arranged in a single row. Due to their hydrodynamic interactions, the spacing between these droplets oscillates with a wave-like motion that is longitudinal or transverse. The simulation yields wave spectra that agree well with experiment. The wave-like motion has an instability which is confirmed to arise from nonlinearities in the interaction potential. The instability's growth is spatially localized. By selecting an appropriate correlation function, the interaction between the longitudinal and transverse waves is described. PMID:23214679

Liu, Bin; Goree, J; Feng, Yan

2012-10-01

278

Temporal coherence of one-dimensional nonequilibrium quantum fluids  

NASA Astrophysics Data System (ADS)

We theoretically investigate the time dependence of the first-order coherence function for a one-dimensional driven dissipative nonequilibrium condensate. Simulations on the generalized Gross-Pitaevskii equation show that the characteristic time scale of exponential decay agrees with the linearized Bogoliubov theory in the regime of large interaction energy. For very weak interactions, the temporal correlation deviates from the linear theory, and instead respects the dynamic scaling of the Kardar-Parisi-Zhang universality class. This nonlinear dynamics is found to be quantitatively captured by a noisy Kuramoto-Sivashinsky equation for the phase dynamics.

Ji, Kai; Gladilin, Vladimir N.; Wouters, Michiel

2015-01-01

279

Computer model of one-dimensional equilibrium controlled sorption processes  

USGS Publications Warehouse

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

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

1984-01-01

280

One-Dimensional Rydberg Gas in a Magnetoelectric Trap  

SciTech Connect

We study the quantum properties of Rydberg atoms in a magnetic Ioffe-Pritchard trap which is superimposed by a homogeneous electric field. Trapped Rydberg atoms can be created in long-lived electronic states exhibiting a permanent electric dipole moment of several hundred Debye. The resulting dipole-dipole interaction in conjunction with the radial confinement is demonstrated to give rise to an effectively one-dimensional ultracold Rydberg gas with a macroscopic interparticle distance. We derive analytical expressions for the electric dipole moment and the required linear density of Rydberg atoms.

Mayle, Michael [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Hezel, Bernd [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Lesanovsky, Igor [Institut fuer Theoretische Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Schmelcher, Peter [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany)

2007-09-14

281

Numerical computations on one-dimensional inverse scattering problems  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

282

Propagation of nonclassical correlations through one-dimensional quantum networks  

NASA Astrophysics Data System (ADS)

We investigate transfer of nonclassical correlations through one-dimensional quantum networks for several schemes by employing concurrence and local quantum uncertainty as the measures and the extended Werner-like states as the initial resources. The exact dynamics of quantum correlations are derived, and the differences of dynamics between concurrence and local quantum uncertainty are analyzed. Besides, the influences of node number and initial parameters on the generation of quantum correlations between the two end nodes are discussed. Moreover, we explore the effects of duplex encodings and double channels on distribution of quantum correlations.

Hu, Zheng-Da; Zhang, Yixin; Zhang, Ye-Qi

2014-08-01

283

Two dimensionality in quasi-one-dimensional cobalt oxides  

Microsoft Academic Search

Magnetism of quasi-one-dimensional (1D) cobalt oxides An+2Con+1O3n+3 (A=Ca, Sr and Ba, n=1–5 and ?) was investigated by ?+SR using polycrystalline samples, at temperatures from 300K down to 1.8K. The wTF–?+SR experiments showed the existence of a magnetic transition in all six samples investigated. The onset temperature of the transition (Tcon) was found to decrease with n; that is, 100±25, 90±10,

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

2006-01-01

284

One-dimensional photonic crystals with cylindrical geometry.  

PubMed

A one-dimensional photonic crystal (1DPC) consisting of a stack of alternate TiO(2) and Al(2)O(3) layers is deposited on the side wall of a glass rod by Atomic Layer Deposition. The stack is designed to sustain TE-polarized Bloch Surface Waves (BSW) in the visible spectrum at wavelengths shorter than 650 nm. Experimental evidence of light coupling and guiding capabilities of the 1DPC is provided together with a possible application for fluorescence-based remote sensors. PMID:25401874

Roussey, Matthieu; Descrovi, Emiliano; Häyrinen, Markus; Angelini, Angelo; Kuittinen, Markku; Honkanen, Seppo

2014-11-01

285

Zener tunneling in one-dimensional organic semiconductors  

NASA Astrophysics Data System (ADS)

Tunneling effect in one-dimensional organic semiconductors in the presence of an external electric field is studied within the framework of a tight-binding model and a nonadiabatic dynamical method. It is found that under a high electric field, electrons can transit from the valence band (VB) to the conduction band (CB), which is demonstrated to be Zener tunneling in organic semiconductors. The results also indicate a field-induced insulator-metal transition accompanied by the vanishing of the energy gap. It is found that, after the field is turned off, the Peierls phase cannot be recovered.

Liu, W.; Li, Y.; Sun, Z.; Liu, D. S.; Xie, S. J.

2008-06-01

286

Breakdown of Thermalization in Finite One-Dimensional Systems  

SciTech Connect

We use quantum quenches to study the dynamics and thermalization of hard core bosons in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.

Rigol, Marcos [Department of Physics, Georgetown University, Washington, D.C. 20057 (United States)

2009-09-04

287

Parallel solution of sparse one-dimensional dynamic programming problems  

NASA Technical Reports Server (NTRS)

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

Nicol, David M.

1989-01-01

288

Optical Tamm States in One-Dimensional Magnetophotonic Structures  

NASA Astrophysics Data System (ADS)

We demonstrate the existence of a spectrally narrow localized surface state, the so-called optical Tamm state, at the interface between one-dimensional magnetophotonic and nonmagnetic photonic crystals. The state is spectrally located inside the photonic band gaps of each of the photonic crystals comprising this magnetophotonic structure. This state is associated with a sharp transmission peak through the sample and is responsible for the substantial enhancement of the Faraday rotation for the corresponding wavelength. The experimental results are in excellent agreement with the theoretical predictions.

Goto, T.; Dorofeenko, A. V.; Merzlikin, A. M.; Baryshev, A. V.; Vinogradov, A. P.; Inoue, M.; Lisyansky, A. A.; Granovsky, A. B.

2008-09-01

289

Saturable discrete vector solitons in one-dimensional photonic lattices  

SciTech Connect

Localized vectorial modes, with equal frequencies and mutually orthogonal polarizations, are investigated both analytically and experimentally in a one-dimensional photonic lattice with defocusing saturable nonlinearity. It is shown that these modes may span over many lattice elements and that energy transfer among the two components is both phase and intensity dependent. The transverse electrically polarized mode exhibits a single-hump structure and spreads in cascades in saturation, while the transverse magnetically polarized mode exhibits splitting into a two-hump structure. Experimentally such discrete vector solitons are observed in lithium niobate lattices for both coherent and mutually incoherent excitations.

Vicencio, Rodrigo A. [Max Planck Institute of Physics of Complex Systems, D-01187 Dresden (Germany); Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Smirnov, Eugene; Rueter, Christian E.; Kip, Detlef [Institute of Physics and Physical Technologies, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld (Germany); Stepic, Milutin [Department of Optical Technologies, National Institute of Metrology, D-38116 Braunschweig, Germany (Germany); Vinca Institute of Nuclear Sciences, P.O.B. 522, 11001 Belgrade (Serbia)

2007-09-15

290

Spin Waves in a One-Dimensional Spinor Bose Gas  

SciTech Connect

We study a one-dimensional (iso)spin 1/2 Bose gas with repulsive {delta}-function interaction by the Bethe Ansatz method and discuss the excitations above the polarized ground state. In addition to phonons the system features spin waves with a quadratic dispersion. We compute analytically and numerically the effective mass of the spin wave and show that the spin transport is greatly suppressed in the strong coupling regime, where the isospin-density (or 'spin-charge') separation is maximal. Using a hydrodynamic approach, we study spin excitations in a harmonically trapped system and discuss prospects for future studies of two-component ultracold atomic gases.

Fuchs, J.N. [Laboratoire de Physique des Solides, Universite Paris-Sud, ba circumflex t. 510, F-91405 Orsay (France); Gangardt, D.M. [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris-Sud, bat. 100, F-91405 Orsay (France); Keilmann, T. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann Str. 1, D-85748 Garching (Germany); Shlyapnikov, G.V. [Laboratoire de Physique Theorique et Modeles Statistiques, Universite Paris-Sud, bat. 100, F-91405 Orsay (France); Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65/67, 1018 XE Amsterdam (Netherlands)

2005-10-07

291

Lateral shift in one-dimensional quasiperiodic chiral photonic crystal  

NASA Astrophysics Data System (ADS)

We investigate the lateral shift of a one-dimensional quasiperiodic photonic crystal consisting of chiral and conventional dielectric materials. The effect of structural irregularity on lateral shift is evaluated by stationary-phase approach. Our results show that the lateral shift can be modulated by varying the structural irregularity in quasiperiodic structure. Besides, the position of peak in lateral shift spectrum stays sensitive to the chiral factor of chiral materials. In comparison with that of periodic structure, quasiperiodic structure provides an extra degree of freedom to manipulate the lateral shift.

Da, Jian; Mo, Qi; Cheng, Yaokun; Liu, Taixiang

2015-02-01

292

Semiclassical spectral correlator in quasi one-dimensional systems  

NASA Astrophysics Data System (ADS)

We investigate the spectral statistics of chaotic clean quasi one-dimensional systems. To do so we represent the spectral correlation function R(epsilon) through derivatives of a generating function and semiclassically approximate the latter in terms of periodic orbits. In contrast to previous work we obtain both non-oscillatory and oscillatory contributions to the correlation function. Both types of contributions are evaluated to leading order in 1/epsilon for systems with and without time-reversal invariance. Our results agree with predictions from the nonlinear sigma model for disordered systems.

Braun, Petr; Müller, Sebastian; Haake, Fritz

2008-10-01

293

Boson pairs in a one-dimensional split trap  

SciTech Connect

We describe the properties of a pair of ultracold bosonic atoms in a one-dimensional harmonic trapping potential with a tunable zero-ranged barrier at the trap center. The full characterization of the ground state is done by calculating the reduced single-particle density, the momentum distribution, and the two-particle entanglement. We derive several analytical expressions in the limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to finite interparticle interactions by numerical solution. As pair interactions in double wells form a fundamental building block for many-body systems in periodic potentials, our results have implications for a wide range of problems.

Murphy, D. S.; McCann, J. F.; Goold, J.; Busch, Th. [Department of Applied Mathematics and Theoretical Physics, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland (United Kingdom); Department of Physics, National University of Ireland, UCC, Cork (Ireland)

2007-11-15

294

Programmers manual for a one-dimensional Lagrangian transport model  

USGS Publications Warehouse

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

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

1986-01-01

295

Quantum Criticality of Quasi-One-Dimensional Topological Anderson Insulators  

NASA Astrophysics Data System (ADS)

We present an analytic theory of quantum criticality in the quasi-one-dimensional topological Anderson insulators of class AIII and BDI. We describe the systems in terms of two parameters (g, ?) representing localization and topological properties, respectively. Surfaces of half-integer valued ? define phase boundaries between distinct topological sectors. Upon increasing system size, the two parameters exhibit flow similar to the celebrated two-parameter flow describing the class A quantum Hall insulator. However, unlike the quantum Hall system, an exact analytical description of the entire phase diagram can be given. We check the quantitative validity of our theory by comparison to numerical transfer matrix computations.

Altland, Alexander; Bagrets, Dmitry; Fritz, Lars; Kamenev, Alex; Schmiedt, Hanno

2014-05-01

296

Spin diffusion in the one-dimensional classical Heisenberg model  

NASA Astrophysics Data System (ADS)

The problem of spin diffusion is studied numerically in the one-dimensional classical Heisenberg model using a deterministic odd-even spin precession dynamics. We demonstrate that spin diffusion in this model is normal in the infinite-temperature limit and one obtains a long-time diffusive tail in the decay of the autocorrelation function. Some variations of the model with different coupling schemes and anisotropy are also studied and we find normal diffusion in all of them. A systematic finite-size analysis also suggests normal diffusive spreading of spin fluctuations, contrary to previous claims of anomalous diffusion. We also briefly discuss spin diffusion in this model at finite temperatures.

Bagchi, Debarshee

2013-02-01

297

Luminescent [Cu4I4] aggregates and [Cu3I3]-cyclic coordination polymers supported by quinolyl-triazoles.  

PubMed

Quinolyl-1,2,3-triazole ligand supported [Cu4I4] stair-step aggregates [Cu4I4(L1)2] (), [Cu4I4(L2)2] (), [Cu4I4(L3)2] (), [Cu4I4(L4)2] (), [Cu4I4(L5)2] (), and six-membered [Cu3I3] metallacycle based coordination polymers [Cu2I2(L6)]n () and [Cu2I2(L7)]n () (ligands are 2-((1H-1,2,3-triazol-1-yl)methyl)quinoline (L1), 2-((4-alkyl-1H-1,2,3-triazol-1-yl)methyl)quinoline (propyl, butyl and isobutyl for L2, L3 and L4, respectively) and 2-(1-((quinolin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)alcohol (methanol, ethanol and propanol for L5, L6 and L7, respectively)) have been prepared and characterized by single-crystal X-ray diffraction (XRD), powder XRD, photoluminescence spectroscopy and thermogravimetric analysis. Complexes are stair-step [Cu4I4] aggregate structures supported by two quinolyl-triazole hybrid ligands. Complexes and are rare cyclic [Cu3I3] aggregate-based 1-D coordination polymers. All ligands adopt a common tridentate-bridging coordination mode. These complexes are strongly luminescent with a yellow emission (500-700 nm) in the solid state. PMID:25727813

Bai, Shi-Qiang; Jiang, Lu; Young, David James; Hor, T S Andy

2015-03-17

298

Vapochromic Behaviour of M[Au(CN)2]2-Based Coordination Polymers (M = Co, Ni)  

PubMed Central

A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(?-OH2)[Au(CN)2]2 yielded visible vapochromic responses for M = Co but not M = Ni; the IR ?CN spectral region changed in every case. A single crystal structure of Zn[Au(CN)2]2(DMSO)2 revealed a corrugated 2-D layer structure with cis-DMSO units. Reacting a Ni(II) salt and K[Au(CN)2] in DMSO yielded the isostructural Ni[Au(CN)2]2(DMSO)2 product. Co[Au(CN)2]2(DMSO)2 and M[Au(CN)2]2(DMF)2 (M = Co, Ni) complexes have flat 2-D square-grid layer structures with trans-bound DMSO or DMF units; they are formed via vapour absorption by solid M(?-OH2)[Au(CN)2]2 and from DMSO or DMF solution synthesis. Co[Au(CN)2]2(pyridine)4 is generated via vapour absorption by Co(?-OH2)[Au(CN)2]2; the analogous Ni complex is synthesized by immersion of Ni(?-OH2)[Au(CN)2]2 in 4% aqueous pyridine. Similar immersion of Co(?-OH2)[Au(CN)2]2 yielded Co[Au(CN)2]2(pyridine)2, which has a flat 2-D square-grid structure with trans-pyridine units. Absorption of pyridine vapour by solid Ni(?-OH2)[Au(CN)2]2 was incomplete, generating a mixture of pyridine-bound complexes. Analyte-free Co[Au(CN)2]2 was prepared by dehydration of Co(?-OH2)[Au(CN)2]2 at 145 °C; it has a 3-D diamondoid-type structure and absorbs DMSO, DMF and pyridine to give the same materials as by vapour absorption from the hydrate. PMID:22737031

Lefebvre, Julie; Kor?ok, Jasmine L.; Katz, Michael J.; Leznoff, Daniel B.

2012-01-01

299

Proton dynamics of two-dimensional oxalate-bridged coordination polymers.  

PubMed

A two-dimensional porous coordination polymer (NH4)2{HOOC(CH2)4COOH}[Zn2(C2O4)3] (abbreviated as (NH4)2(adp)[Zn2(ox)3] (adp = adipic acid, ox = oxalate)), which accommodates water molecules between the [Zn2(ox)3] layers, is highly remarked as a new type of crystalline proton conductor. In order to investigate its phase behavior and the proton conducting mechanism, we have performed adiabatic calorimetry, neutron diffraction, and quasi-elastic neutron scattering experiments on a fully hydrated sample (NH4)2(adp)[Zn2(ox)3]·3H2O with the highest proton conductivity (8 × 10(-3) S cm(-1), 25 °C, 98% RH). Its isostructural derivative K2(adp)[Zn2(ox)3]·3H2O was also measured to investigate the role of ammonium ions. (NH4)2(adp)[Zn2(ox)3]·3H2O and K2(adp)[Zn2(ox)3]·3H2O exhibit higher order transitions at 86 K and 138 K, respectively. From the magnitude of the transition entropy, the former is of an order-disorder type while the latter is of a displacive type. (NH4)2(adp)[Zn2(ox)3]·3H2O has four Debye-type relaxations and K2(adp)[Zn2(ox)3]·3H2O has two similar relaxations above each transition temperature. The two relaxations of (NH4)2(adp)[Zn2(ox)3]·3H2O with very small activation energies (?Ea < 5 kJ mol(-1)) are due to the rotational motions of ammonium ions and play important roles in the proton conduction mechanism. It was also found that the protons in (NH4)2(adp)[Zn2(ox)3]·3H2O are carried through a Grotthuss mechanism. We present a discussion on the proton conducting mechanism based on the present structural and dynamical information. PMID:25019223

Miyatsu, Satoshi; Kofu, Maiko; Nagoe, Atsushi; Yamada, Takeshi; Sadakiyo, Masaaki; Yamada, Teppei; Kitagawa, Hiroshi; Tyagi, Madhusudan; García Sakai, Victoria; Yamamuro, Osamu

2014-08-28

300

Hydrogen peroxide stabilization in one-dimensional flow columns  

NASA Astrophysics Data System (ADS)

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

2011-09-01

301

Hydrogen peroxide stabilization in one-dimensional flow columns.  

PubMed

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H(2)O(2) propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO. PMID:21700356

Schmidt, Jeremy T; Ahmad, Mushtaque; Teel, Amy L; Watts, Richard J

2011-09-25

302

Bound states of Dipolar Bosons in One-dimensional Systems  

E-print Network

We consider one-dimensional tubes containing bosonic polar molecules. The long-range dipole-dipole interactions act both within a single tube and between different tubes. We consider arbitrary values of the externally aligned dipole moments with respect to the symmetry axis of the tubes. The few-body structures in this geometry are determined as function of polarization angles and dipole strength by using both essentially exact stochastic variational methods and the harmonic approximation. The main focus is on the three, four, and five-body problems in two or more tubes. Our results indicate that in the weakly-coupled limit the inter-tube interaction is similar to a zero-range term with a suitable rescaled strength. This allows us to address the corresponding many-body physics of the system by constructing a model where bound chains with one molecule in each tube are the effective degrees of freedom. This model can be mapped onto one-dimensional Hamiltonians for which exact solutions are known.

A. G. Volosniev; J. R. Armstrong; D. V. Fedorov; A. S. Jensen; M. Valiente; N. T. Zinner

2013-04-27

303

Constraint and gauge shocks in one-dimensional numerical relativity  

E-print Network

We study how different types of blow-ups can occur in systems of hyperbolic evolution equations of the type found in general relativity. In particular, we discuss two independent criteria that can be used to determine when such blow-ups can be expected. One criteria is related with the so-called geometric blow-up leading to gradient catastrophes, while the other is based upon the ODE-mechanism leading to blow-ups within finite time. We show how both mechanisms work in the case of a simple one-dimensional wave equation with a dynamic wave speed and sources, and later explore how those blow-ups can appear in one-dimensional numerical relativity. In the latter case we recover the well known ``gauge shocks'' associated with Bona-Masso type slicing conditions. However, a crucial result of this study has been the identification of a second family of blow-ups associated with the way in which the constraints have been used to construct a hyperbolic formulation. We call these blow-ups ``constraint shocks'' and show that they are formulation specific, and that choices can be made to eliminate them or at least make them less severe.

Bernd Reimann; Miguel Alcubierre; José A. González; Darío Núñez

2005-03-03

304

One-Dimensional Random Systems with Long Range Interactions.  

NASA Astrophysics Data System (ADS)

We consider two one dimensional models of disorder. A percolation model is defined on a one dimensional chain. The bond occupation probability depends on the bond length as. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). A percolation threshold exists for 1 (LESSTHEQ) (sigma) (LESSTHEQ) 2, as a function of K. The critical behaviour is analysed using a renormalization group developed for this problem. The spin glass model is defined by an Ising chain with hamiltonian. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). The J(,ij) are Gaussian random variables with zero mean and variance J('2). We find a phase transition for 1/2 < (sigma) < 1. For 1 < (sigma) < 2/3 the system has classical critical behaviour. Near (sigma) = 1 we find a smooth specific heat. We investigate the critical behaviour near the upper and lower critical range using the renormalization group and an (epsilon) expansion around the lower and upper critical range, (sigma) = 2/3 and (sigma) = 1.

Kotliar, Bernardo Gabriel

305

Dislocation-mediated melting of one-dimensional Rydberg crystals  

SciTech Connect

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

Sela, Eran; Garst, Markus [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, DE-50937 Koeln (Germany); Punk, Matthias [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse, DE-85748 Garching (Germany); Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-08-15

306

A Yb(III)-Zn(II) heterometallic coordination polymer with interesting three-fold 1D pseudo-nanotube architectures  

NASA Astrophysics Data System (ADS)

A heterometallic coordination polymer formulated as [YbZn(btc)(OH)2(H2O)]·H2O (1), where H3btc = 1,3,5-benzenetricarboxylic acid has been synthesized under hydrothermal condition. Single crystal analysis reveals that complex 1 presents a three-dimensional (3D) structure containing three-fold 1D pseudo-nanotube architectures. The complex has also been characterized by IR, PXRD, TG and elemental analysis. Moreover, solid-state photoluminescence property of the complex has also been investigated at room temperature.

Xu, Bo; Yuan, Senwen; Zhang, Xiutao; Li, Cuncheng

2014-06-01

307

Characterisation and cryomagnetic study of a hydrothermally synthesised hydrogen bonded L–M–L type co-ordination polymer  

Microsoft Academic Search

A ligand–metal–ligand type co-ordination polymer [Ni (C6H12N4)(NCS)2(H2O)2]\\u000a n\\u000a has been synthesised under controlled hydrothermal conditions. Here 1,3,5,7-tetraazatricyclo[3.3.1]decane [or hexamethylenetetramine (hmt)] has been used as a ?-(N,N?) bidentate spacer molecule. The prepared polymeric complex has been characterised by elemental and spectral analyses. The structure has been confirmed by a single crystal X-ray diffraction study. Magneto-structural correlation has been drawn from cryomagnetic

Joy Chakraborty; Brajagopal Samanta; Andrei S. Batsanov; Joan Ribas; M. Salah El Fallah; Samiran Mitra

2006-01-01

308

Two new hydrothermally synthesised hexamine bridged L–M–L type coordination polymers: Characterisation and magneto-structural correlation  

Microsoft Academic Search

Two new L–M–L type transition metal coordination polymers [M(C6H12N4)(NCO)2(H2O)2]n, where M=Co(II) (1) and Ni(II) (2), have been synthesised under controlled hydrothermal condition and characterised spectroscopically and by thermal analyses. Here hmt or hexamethylenetetramine has behaved as a neutral organic bidentate spacer molecule. Both the complexes crystallise in the monoclinic system as confirmed from single crystal X-ray diffraction studies. Cryomagnetic susceptibility

Aurkie Ray; Joy Chakraborty; Brajagopal Samanta; Santarupa Thakurta; C. Marschner; M. Salah El Fallah; Samiran Mitra

2008-01-01

309

Structural and spectral properties of a zinc(II) coordination polymer: a combined experimental and theoretical study.  

PubMed

A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm=1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through ?-? stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385nm and 450nm could respectively be assigned to the ???(*) transition within the bbbm ligands and ??n transition from chloride anion to bbbm ligand. PMID:24820328

Hao, Jin-Ming; Li, Guang-Yue; Li, Yue-Hua; Cui, Guang Hua

2014-10-15

310

Structural and spectral properties of a zinc(II) coordination polymer: A combined experimental and theoretical study  

NASA Astrophysics Data System (ADS)

A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm = 1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through ?-? stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385 nm and 450 nm could respectively be assigned to the ? ? ?* transition within the bbbm ligands and ? ? n transition from chloride anion to bbbm ligand.

Hao, Jin-Ming; Li, Guang-Yue; Li, Yue-Hua; Cui, Guang Hua

2014-10-01

311

One-dimensional non-stationary convection model  

NASA Astrophysics Data System (ADS)

One-dimensional convection model is widely used in large-scale atmospheric models for the description of the convective clouds and calculating precipitation. Such models are stationary and can not describe the dynamics of the convection. There are widely used the non-stationary version of the one-dimensional models that are remaining within the framework of the simple versions. Evaluation of the convection processes in these models differs from the stationary version. If we consider the results of the stationary version as an initial condition for the non-stationary model, then in the process of solving the non-stationary task it will be the development of convection and establishing of the convective. In the present paper the equation processes for the vertical velocity are considered. That contains the time derivative. It is solved by the finite-difference scheme for a variety of levels k. The number of the levels k is determined by the spline approximation of the input data. As a result we have a quadratic equation for the vertical velocity w, taking into account the effects of entrainment, detrainment and release of condensation heat. If the vertical velocity in the calculation is positive, we assume the formation of the cloud elements. Based on the equations for the specific humidity q, water content ? and the statistical stability s, and introduce to them the time derivatives we obtain the equations system for the one-dimensional non-stationary cloud model, that take into account the processes occurring inside the cloud and in the surrounding area. Also here is presented an approach for the calculation of the precipitation. Many experiments using the model were performed to optimize the input parameters, empirical coefficients and calculated algorithm. The calculations showed that all model parameters are changing over time and finally the development process is stabilized. This is due to the surrounding state of the atmosphere that does not changed in these calculations. Value of the time steps for the integration in the cloud and the time steps of changing the environment parameters must be conformed: the period of convection is less than the step of change in the external environment. In our case we choose a step in non-stationary cloud model up to 10 seconds. The model is convenient to use because minimum of the input data is required: the geopotential, pressure, temperature and humidity. At the output the model can provide quick calculations and fairly realistic values of the vertical velocity, precipitation, and the various parameters of the clouds. The presented algorithm can be adapted to large-scale hydrodynamical models of the atmosphere.

Sadokov, V. P.; Vasilevsky, K. D.

2012-04-01

312

Progress on one-dimensional zinc oxide nanomaterials based photonic devices  

NASA Astrophysics Data System (ADS)

One-dimensional nanostructures hold the most attractive and excellent physiochemical characteristics which exhibit the paramount influence on the fundamental and technological nanoelectronic as well as nanophotonic applications. In this review article, we present a detailed introduction to the diverse synthetic procedures which can be utilized for the fabrication of single-, planar- and three-dimensional ZnO nanostructures. More specifically, a thorough discussion regarding luminescence characteristics of the one-dimensional ZnO nanostructures is presented for ultraviolet and visible regions. We summarize the room temperature spontaneous emission and stimulated emission along with the interaction of the incident beam with material cavity to produce resonant optical modes and low-temperature time resolved photoluminescence studies. The most recent published results on the white light emitting diodes fabricated with the combination of ZnO nanotubes with p-GaN and ZnO nanorods with p-organic polymers on glass and disposable paper are discussed. Additionally, the significant results on optically and electrically pumped lasers are discussed; along with an overview on the future of ZnO nanostructures based photonic devices.

Willander, Magnus; Israr, Muhammad Q.; Sadaf, Jamil R.; Nur, Omer

2012-07-01

313

Transport through quasi-one-dimensional wires with correlated disorder  

NASA Astrophysics Data System (ADS)

We study transport properties of bulk-disordered quasi-one-dimensional (Q1D) wires paying main attention to the role of long-range correlations embedded into the disorder. First, we show that for stratified disorder for which the disorder is the same for all individual chains forming the Q1D wire, the transport properties can be analytically described provided the disorder is weak. When the disorder in every chain is not the same, however it has the same binary correlator, the general theory is absent. Thus, we consider the case when only one channel is open and all others are closed. For this situation we suggest a semianalytical approach which is quite effective for the description of the total transmission coefficient. Our numerical data confirm the validity of this approach.

Herrera-González, I. F.; Méndez-Bermúdez, J. A.; Izrailev, F. M.

2014-10-01

314

Erosion by a one-dimensional random walk  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

315

Growth of One-Dimensional MnO2 Nanostructure  

NASA Astrophysics Data System (ADS)

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

Lu, Pai; Xue, Dongfeng

316

Erosion by a one-dimensional random walk.  

PubMed

We consider a model introduced by Baker et al. [Phys. Rev. E 88, 042113 (2013)] of a single lattice random walker moving on a domain of allowed sites, surrounded by blocked sites. The walker enlarges the allowed domain by eroding the boundary at its random encounters with blocked boundary sites: attempts to step onto blocked sites succeed with a given probability and convert these sites to allowed sites. The model interpolates continuously between the Pólya random walker on the one-dimensional lattice and a "blind" walker who attempts freely, but always aborts, moves to blocked sites. We obtain some exact results about the walker's location and the rate of erosion. PMID:25215721

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

2014-08-01

317

Observations on one-dimensional counterflow diffusion problem  

NASA Astrophysics Data System (ADS)

The proposed paper will describe development of a time-dependent, one-dimensional counterflow diffusion model meant to help study the issue of helium exposure of the IRU (Inertial Reference Unit) used in the Earth Observing-1 (EO-1) spacecraft. The IRU features sensitive quartz crystal hemispherical resonating gyros (HRG's). Although the IRU enclosure was purged with high-purity liquid boil-off nitrogen, the HRG's were still quite susceptible to contamination generated by exposure of the enclosure to levels of helium above atmospheric background levels. This helium would be preferentially collected by the HRG's, changing their mass, and hence the driving voltage required for operations. The paper will discuss a comparison of theoretical results with test data for an IRU enclosure, and how contaminant gases can enter vent holes despite the presence of a purge. These observations are then used to describe a possible improvement for purge effectiveness.

Woronowicz, Michael S.

2002-09-01

318

Dynamic correlation functions in one-dimensional quasicondensates  

SciTech Connect

We calculate the static and dynamic single-particle correlation functions in one-dimensional (1D) trapped Bose gases and discuss experimental measurements that can directly probe such correlation functions. Using a quantized hydrodynamic theory for the low-energy excitations, we calculate both the static and dynamic single-particle correlation functions for a 1D Bose gas that is a phase-fluctuating quasicondensate. For the static (equal-time) correlation function, our approximations and results are equivalent to those of Petrov, Shlyapnikov, and Walraven. The Fourier transform of the static single-particle correlation function gives the momentum distribution, which can be measured using Doppler-sensitive Bragg scattering experiments on a highly elongated Bose gas. We show how a two-photon Raman out-coupling experiment can measure the characteristic features of the dynamic or time-dependent single-particle correlation function of a 1D Bose quasicondensate.

Luxat, D.L.; Griffin, A. [Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

2003-04-01

319

Dynamic correlation functions in one-dimensional quasi-condensates  

E-print Network

We calculate the static and dynamic single-particle correlation functions in one-dimensional (1D) trapped Bose gases and discuss experimental measurements that can directly probe such correlation functions. Using a quantized hydrodynamic theory for the low energy excitations, we calculate both the static and dynamic single-particle correlation functions for a 1D Bose gas that is a phase-fluctuating quasi-condensate. For the static (equal-time) correlation function, our approximations and results are equivalent to those of Petrov, Shlyapnikov and Walraven. The Fourier transform of the static single-particle correlation function gives the momentum distribution, which can be measured using Doppler-sensitive Bragg scattering experiments on a highly elongated Bose gas. We show how a two-photon Raman out-coupling experiment can measure the characteristic features of the dynamic or time-dependent single-particle correlation function of a 1D Bose quasi-condensate.

D. L. Luxat; A. Griffin

2002-12-04

320

One-dimensional planar hydrodynamic theory of shock ignition  

SciTech Connect

A one-dimensional planar compressible-piston-like model is used to investigate the basic physics behind shock-ignition inertial confinement fusion implosions. We discuss the theoretical limit set by rarefaction waves on the maximum hot-spot pressure achievable through conventional compression. Three ignitor shock techniques are presented to mitigate the effects of rarefaction waves, enhance the stagnation hot-spot pressure, and improve the ignition conditions. Elimination of rarefaction waves can lead to an {approx}80% increase in peak implosion pressures, while implosions augmented with ignitor shocks are shown to increase the peak pressures by a factor of {approx}4. These techniques are then discussed and the optimal energy ratio between the initial shell kinetic energy and the ignitor pulse energy is given.

Nora, R.; Betti, R. [Fusion Science Center and Laboratory for Laser Energetics, Physics and Astronomy, University of Rochester, Rochester, New York 14623 (United States)

2011-08-15

321

Magnetoresistance anisotropy of a one-dimensional superconducting niobium strip.  

PubMed

We investigated confinement effects on the resistive anisotropy of a superconducting niobium strip with a rectangular cross section. When its transverse dimensions are comparable to the superconducting coherence length, the angle dependent magnetoresistances at a fixed temperature can be scaled as R(theta,H) = R(H/Hctheta) where Hctheta =Hc0(cos2theta + gamma(-2)sin2theta)(-1/2) is the angular dependent critical field, gamma is the width to thickness ratio, and Hc0 is the critical field in the thickness direction at theta=0 degrees . The results can be understood in terms of the anisotropic diamagnetic energy for a given field in a one-dimensional superconductor. PMID:18764568

Hua, J; Xiao, Z L; Imre, A; Yu, S H; Patel, U; Ocola, L E; Divan, R; Koshelev, A; Pearson, J; Welp, U; Kwok, W K

2008-08-15

322

One-dimensional plasma photonic crystals with sinusoidal densities  

SciTech Connect

Properties of electromagnetic waves with normal and oblique incidence have been studied for one-dimensional plasma layers with sinusoidal densities. Wave transmittance as a function of wave frequency exhibits photonic band gaps characteristic of photonic crystals. For periodic structures, increasing collision frequency is demonstrated to lead to greater absorption, increasing the modulation factor enlarges the gap width, and increasing incidence angle can change the gap locations of the two polarizations. If a defect layer is introduced by inserting a new plasma layer in the center, a defect mode may appear within the gap. Periodic number, collision frequency, and modulation factor can affect magnitude of the defect mode. The incidence angle enables the frequency to be tuned. Defect layer thickness affects both frequency and number of defect modes. These results may provide theoretical guidance in designing tunable narrow-band filters.

Qi, L., E-mail: qilimei1204@163.com; Shang, L.; Zhang, S. [College of Physics and Engineering, Qufu Normal University, No. 57, West Jingxuan Road, Qufu 273165 (China)] [College of Physics and Engineering, Qufu Normal University, No. 57, West Jingxuan Road, Qufu 273165 (China)

2014-01-15

323

Solvation-induced one-dimensional polarons and electron transfer.  

PubMed

When a one-dimensional (1D) semiconductor nanostructure is immersed in a sluggish polar solvent, fluctuations of the medium may result in the appearance of localized electronic levels inside the band gap. An excess charge carrier can occupy such a level and undergo self-localization into a large-radius adiabatic polaron surrounded by a self-consistent medium polarization pattern. Within an appropriately adapted framework of the Marcus theory, we explore the description and qualitative picture of thermally activated electron transfer involving solvation-induced polaroniclike states by considering transfer between small and 1D species as well as between two 1D species. Illustrative calculations are performed for tubular geometries with possible applications to carbon nanotube systems. PMID:20441283

Ussery, G L; Gartstein, Yu N

2010-04-28

324

Dimer kinetics in a one-dimensional lattice  

NASA Astrophysics Data System (ADS)

The kinetics of dimer molecules in a one-dimensional lattice is formulated in the framework of the kinetic lattice gas model. Local evolution rules are used to obtain the hierarchy of equations of motion for correlation functions where processes like adsorption, desorption and surface diffusion are included. By use of mean-field ( m, n) closures, that allow the truncation of the infinite set of coupled differential equations of motion, we obtain the equilibrium properties and the time evolution of the adsorbate as well as the desorption kinetics. The temperature-programmed desorption (TPD) spectra for mobile and immobile adsorbates are obtained as limiting cases. The effect of the diffusion on TPD is also analyzed.

Costanza, G.; Manzi, S.; Pereyra, V. D.

2003-02-01

325

Topological charge pumping in a one-dimensional optical lattice.  

PubMed

A topological charge pump transfers charge in a quantized fashion. The quantization is stable against the detailed form of the pumping protocols and external noises and shares the same topological origin as the quantum Hall effect. We propose an experimental setup to realize topological charge pumping of cold fermionic atoms in a one-dimensional optical lattice. The quantization of the pumped charge is confirmed by first-principles simulations of the dynamics of uniform and trapped systems. Quantum effects are shown to be crucial for the topological protection of the charge quantization. Finite-temperature and nonadiabatic effects on the experimental observables are discussed. The realization of such a topological charge pump serves as a firm step toward exploring topological states and nonequilibrium dynamics using cold atoms. PMID:23889428

Wang, Lei; Troyer, Matthias; Dai, Xi

2013-07-12

326

Diffusive radiation in one-dimensional Langmuir turbulence.  

PubMed

We calculate spectra of radiation produced by a relativistic particle in the presence of one-dimensional Langmuir turbulence which might be generated by a streaming instability in the plasma, in particular, in the shock front or at the shock-shock interactions. The shape of the radiation spectra is shown to depend sensitively on the angle between the particle velocity and electric field direction. The radiation spectrum in the case of exactly transverse particle motion is degenerate and similar to that of spatially uniform Langmuir oscillations. In the case of oblique propagation, the spectrum is more complex, it consists of a number of power-law regions and may contain a distinct high-frequency spectral peak. The emission process considered is relevant to various laboratory plasma settings and for astrophysical objects as gamma-ray bursts and collimated jets. PMID:17677604

Fleishman, G D; Toptygin, I N

2007-07-01

327

Properties of surface modes in one dimensional plasma photonic crystals  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

328

Spectrum of normal waves in one-dimensional magnonic crystals  

NASA Astrophysics Data System (ADS)

A general theory of the spectrum of normal waves propagating in magnetic structures with periodically modulated parameters has been developed. Based on the method of tensorial Green's functions, spin-wave mode approach, and Floquet-Bloch theorem, a general form of the dispersion relation has been obtained for dipole-exchange spin waves propagating in a one-dimensional magnonic crystal formed by an arbitrary spatially periodic modulation of all magnetic and geometric parameters in the Maxwell's equations and the Landau-Lifshitz equation. An original method has been proposed for taking into account an arbitrary profile of the modulation of the chosen parameters. The efficiency of the presented theory has been demonstrated using a simple example of the description of an experimental spectrum of a dynamic magnonic crystal.

Grigoryeva, N. Yu.; Kalinikos, B. A.

2014-11-01

329

Atom-Molecule Coherence in a One-Dimensional System  

NASA Astrophysics Data System (ADS)

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

Citro, R.; Orignac, E.

2005-09-01

330

Quantum quench dynamics in analytically solvable one-dimensional models  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

331

Critical conductance of a one-dimensional doped Mott insulator  

NASA Astrophysics Data System (ADS)

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

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

2008-01-01

332

Counter Chemotactic Flow in Quasi-One-Dimensional Path  

NASA Astrophysics Data System (ADS)

Quasi-one-dimensional bidirectional particle flow including the effect of chemotaxis is investigated through a modification of the John-Schadschneider-Chowdhury-Nishinari model. Specifically, we permit multiple lanes to be shared by both directionally traveling particles. The relation between particle density and flux is studied for several evaporation rates of pheromone, and the following results are obtained: i) in the low-particle-density range, the flux is enlarged by pheromone if the pheromone evaporation rate is sufficiently low, ii) in the high particle-density range, the flux is largest at a reasonably high evaporation rate and, iii) if the evaporation rate is at the level intermediate between the above two cases, the flux is kept small in the entire range of particle densities. The mechanism of these behaviors is investigated by observing the spatiotemporal evolution of particles and the average cluster size in the system.

Fujii, Masashi; Awazu, Akinori; Nishimori, Hiraku

2009-07-01

333

Microwave properties of nonlinear one-dimensional quasiperiodic photonic crystals  

NASA Astrophysics Data System (ADS)

The nonlinear properties of quasi-periodic photonic crystals based on the Thue-Morse and Fibonacci sequence are investigated. We address the transmission properties of waves through one dimensional symmetric Fibonacci, and Thue-Morse system i.e., a quasiperiodic structure made up of two different dielectric materials (Rogers and air), in quarter wavelength condition, presenting in the one directions. The microwave spectra are calculated by using transfer matrix method in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the microwave properties through a return map of the transmission coefficients. We extract powerfully the band gaps of quasi-periodic multilayered structures, called `pseudo band gaps' often contain resonant states, which can be considered as a manifestation of numerous defects distributed along the structure. Taken together, the above two properties provide favorable conditions for the design of an all-microwave reflector.

Trabelsi, Y.; Kanzari, M.

2012-06-01

334

Asymptotics of one-dimensional forest fire processes  

E-print Network

We consider the so-called one-dimensional forest fire process. At each site of $\\mathbb{Z}$, a tree appears at rate $1$. At each site of $\\mathbb{Z}$, a fire starts at rate ${\\lambda}>0$, immediately destroying the whole corresponding connected component of trees. We show that when ${\\lambda}$ is made to tend to $0$ with an appropriate normalization, the forest fire process tends to a uniquely defined process, the dynamics of which we precisely describe. The normalization consists of accelerating time by a factor $\\log(1/{\\lambda})$ and of compressing space by a factor ${\\lambda}\\log(1/{\\lambda})$. The limit process is quite simple: it can be built using a graphical construction and can be perfectly simulated. Finally, we derive some asymptotic estimates (when ${\\lambda}\\to0$) for the cluster-size distribution of the forest fire process.

Xavier Bressaud; Nicolas Fournier

2010-11-05

335

One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts  

NASA Astrophysics Data System (ADS)

We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM10 hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 105?-3. Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated.

Lu, Tsan-Wen; Lin, Pin-Tso; Lee, Po-Tsung

2014-05-01

336

Fast one-dimensional profilometer with a compact disc pickup.  

PubMed

The use of compact disc (CD) pickups in optical profilometry is a well-established practice. The instruments currently available on the market are, however, expensive both to purchase and to maintain. This expense is mainly due to the high cost of the scanning system, and it makes the use of low-cost pickups fruitless. Moreover, translation stages are bulky, slow, and in most applications neither necessary nor desirable. We present a one-dimensional profilometer, which uses a CD pickup as both the sensor and the actuator. Beam scanning of the sample is in fact performed by the objective lens tracking motor. The device is cheap, fast, compact, light, and a valuable solution for fluid and hard-to-access surface profiling. PMID:18357088

Bartoli, A; Poggi, P; Quercioli, F; Tiribilli, B

2001-03-01

337

One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts  

SciTech Connect

We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM{sub 10} hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 10{sup 5}?{sup ?3}. Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated.

Lu, Tsan-Wen; Lin, Pin-Tso; Lee, Po-Tsung, E-mail: potsung@mail.nctu.edu.tw [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Rm. 413 CPT Building, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan (China)

2014-05-12

338

Experiment and simulation on one-dimensional plasma photonic crystals  

SciTech Connect

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

Zhang, Lin; Ouyang, Ji-Ting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

2014-10-15

339

Magnetic polarons in the one-dimensional ferromagnetic Kondo model  

NASA Astrophysics Data System (ADS)

The ferromagnetic Kondo model with classical corespins is studied via unbiased Monte Carlo simulations. We show that with realistic parameters for the manganites and at low temperatures, the double-exchange mechanism does not lead to phase separation in one-dimensional chains but rather stabilizes individual ferromagnetic polarons. Within the ferromagnetic polaron picture, the pseudogap in the one-particle spectral function Ak(?) can easily be explained. Ferromagnetic polarons also clear up a seeming failure of the double-exchange mechanism in explaining the comparable bandwidths in the ferromagnetic and paramagnetic phase. For our analysis, we extend a simplified model, the finite-temperature uniform hopping approach (UHA), to include polarons. It can easily be evaluated numerically and provides a simple quantitative understanding of the physical features of the ferromagnetic Kondo model.

Koller, Winfried; Prüll, Alexander; Evertz, Hans Gerd; von der Linden, Wolfgang

2003-05-01

340

Quasi one dimensional transport in individual electrospun composite nanofibers  

SciTech Connect

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

Avnon, A., E-mail: avnon@phys.fu-berlin.de; Datsyuk, V.; Trotsenko, S. [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)] [Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany); Wang, B.; Zhou, S. [Research Center of Microperipheric Technologies, Technische Universität Berlin, TiB4/2-1, Gustav-Meyer-Allee 25, 13355 Berlin (Germany)] [Research Center of Microperipheric Technologies, Technische Universität Berlin, TiB4/2-1, Gustav-Meyer-Allee 25, 13355 Berlin (Germany); Grabbert, N.; Ngo, H.-D. [Microsystem Engineering (FB I), University of Applied Sciences, Wilhelminenhofstr. 74 (C 525), 12459 Berlin (Germany)] [Microsystem Engineering (FB I), University of Applied Sciences, Wilhelminenhofstr. 74 (C 525), 12459 Berlin (Germany)

2014-01-15

341

Jamming and dynamics in Confined Quasi-One Dimensional Systems  

NASA Astrophysics Data System (ADS)

Geometrically confining particles to a quasi-one dimensional arrangement so that they can only interact with their nearest neighbours simplifies the way the particles can pack to the extent that we can calculate the distribution of jammed packings exactly, making them ideal systems for exploring the connection between jamming and dynamics. We study the mean squared displacement (MSD) of a system of two dimensional hard discs subject to inertial motion and confined to a single file by two hard lines. At low densities the MSD of the discs increases linearly with time, consistent with the Einstein relation for normal diffusion. However, at high densities the system exhibits anomalous diffusion, where the MSD is proportional to t^1/2. We show how this dynamic transition is related to the nature and distribution of jammed structures. We also use this simple system to examine the role of dynamic heterogeneity in the motion of dense confined fluids.

Bowles, R. K.; Mon, K. K.; Percus, J. K.

2005-03-01

342

Magnons in one-dimensional k-component Fibonacci structures  

SciTech Connect

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

Costa, C. H., E-mail: carloshocosta@hotmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Vasconcelos, M. S. [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)

2014-05-07

343

Is a multi walled nanotube one-dimensional?  

NASA Astrophysics Data System (ADS)

Despite the structural similarity between the single and multi walled nanotubes (SWNTs and MWNTs), the nature of electron transport in these systems was found to be fundamentally different. In contrast to a SWNT, where conduction electrons are constrained to interact in a strictly one--dimensional manner (Luttinger-liquid system), electron excitations in a MWNT exhibit a distinct multi--dimensional Fermi--liquid behavior. The latter was demonstrated experimentally by comparing the femtosecond decay dynamics of electrons excited into different conduction bands of a MWNT, consisting, on average, of 15 coaxial SWNT shells. The observed temporal evolution provides strong evidence that long--range e--e interaction along the tube vanishes due to screening, indicating that multi-- dimensional nature of charge propagation should be invoked in modeling electronic properties of MWNTs. This work was supported by Chemical Sciences, Geo--sciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U. S. Department of Energy.

Zamkov, Mikhail

2005-05-01

344

Magnons in one-dimensional k-component Fibonacci structures  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

345

Loschmidt echo in one-dimensional interacting Bose gases  

SciTech Connect

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

Lelas, K.; Seva, T.; Buljan, H. [Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture, University of Split, Rudjera Boskovica BB, 21000 Split (Croatia); Department of Physics, University of Zagreb, Bijenicka c. 32, 10000 Zagreb (Croatia)

2011-12-15

346

Users manual for a one-dimensional Lagrangian transport model  

USGS Publications Warehouse

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

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

1986-01-01

347

Strongly-Refractive One-Dimensional Photonic Crystal Prisms  

NASA Technical Reports Server (NTRS)

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

Ting, David Z. (Inventor)

2004-01-01

348

Quantum Teleportation in One-Dimensional Quantum Dots System  

E-print Network

We present a model of quantum teleportation protocol based on one-dimensional quantum dots system. Three quantum dots with three electrons are used to perform teleportation, the unknown qubit is encoded using one electron spin on quantum dot A, the other two dots B and C are coupled to form a mixed space-spin entangled state. By choosing the Hamiltonian for the mixed space-spin entangled system, we can filter the space (spin) entanglement to obtain pure spin (space) entanglement and after a Bell measurement, the unknown qubit is transfered to quantum dot B. Selecting an appropriate Hamiltonian for the quantum gate allows the spin-based information to be transformed into a charge-based information. The possibility of generalizing this model to N-electrons is discussed.

Hefeng Wang; Sabre Kais

2006-05-18

349

Heterobimetallic MOFs containing tetrathiocyanometallate building blocks: pressure-induced spin crossover in the porous {Fe(II)(pz)[Pd(II)(SCN)4]} 3D coordination polymer.  

PubMed

Here we describe the synthesis, structure, and magnetic properties of two related coordination polymers made up of self-assembling Fe(II) ions, pyrazine (pz), and the tetrathiocyanopalladate anion. Compound {Fe(MeOH)(2)[Pd(SCN)(4)]}·pz (1a) is a two-dimensional coordination polymer where the Fe(II) ions are equatorially coordinated by the nitrogen atoms of four [Pd(SCN)(4)](2-) anions, each of which connects four Fe(II) ions, forming corrugated layers {Fe[Pd(SCN)(4)]}(?). The coordination sphere of Fe(II) is completed by the oxygen atoms of two CH(3)OH molecules. The layers stack one on top of each other in such a way that the included pz molecule establishes strong hydrogen bonds with the coordinated methanol molecules of adjacent layers. Compound {Fe(pz)[Pd(SCN)(4)]} (2) is a three-dimensional porous coordination polymer formed by flat {Fe[Pd(SCN)(4)]}(?) layers pillared by the pz ligand. Thermal analysis of 1a shows a clear desorption of the two coordinated CH(3)OH molecules giving a rather stable phase (1b), which presumably is a polymorphic form of 2. The magnetic properties of the three derivatives are typical of the high-spin Fe(II) compounds. However, compounds 1b and 2, with coordination sphere [FeN(6)], show thermal spin crossover behavior at pressures higher than ambient pressure (10(5) MPa). PMID:23009692

Muñoz-Lara, Francisco J; Arcís-Castillo, Zulema; Muñoz, M Carmen; Rodríguez-Velamazán, J Alberto; Gaspar, Ana B; Real, José A

2012-10-15

350

One-dimensional cloud fluid model for propagating star formation  

NASA Technical Reports Server (NTRS)

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

Titus, Timothy N.; Struck-Marcell, Curtis

1990-01-01

351

A One-Dimensional Synthetic-Aperture Microwave Radiometer  

NASA Technical Reports Server (NTRS)

A proposed one-dimensional synthetic- aperture microwave radiometer could serve as an alternative to either the two-dimensional synthetic-aperture radiometer described in the immediately preceding article or to a prior one-dimensional one, denoted the Electrically Scanned Thinned Array Radiometer (ESTAR), mentioned in that article. The proposed radiometer would operate in a pushbroom imaging mode, utilizing (1) interferometric cross-track scanning to obtain cross-track resolution and (2) the focusing property of a reflector for along-track resolution. The most novel aspect of the proposed system would be the antenna (see figure), which would include a cylindrical reflector of offset parabolic cross section. The reflector could be made of a lightweight, flexible material amenable to stowage and deployment. Other than a stowage/deployment mechanism, the antenna would not include moving parts, and cross-track scanning would not entail mechanical rotation of the antenna. During operation, the focal line, parallel to the cylindrical axis, would be oriented in the cross-track direction, so that placement of receiving/radiating elements at the focal line would afford the desired along-track resolution. The elements would be microwave feed horns sparsely arrayed along the focal line. The feed horns would be oriented with their short and long cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis to obtain fan-shaped beams having their broad and narrow cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis. The interference among the beams would be controlled in the same manner as in the ESTAR to obtain along-cylindrical- axis (cross-track) resolution and cross-track scanning.

Doiron, Terence; Piepmeier, Jeffrey

2010-01-01

352

Fabrication of spinel one-dimensional architectures by single-spinneret electrospinning for energy storage applications.  

PubMed

A facile and general method is developed to fabricate one-dimensional (1D) spinel composite oxides with complex architectures by using a facile single-spinneret electrospinning technique. It is found that precursor polymers and heating rates could control the structures of the products, such as 1D solid, nanotube and tube-in-tubes structures. Especially, the tube-in-tube structures have been successfully fabricated for various mixed metal oxide, including CoMn2O4, NiCo2O4, CoFe2O4, NiMn2O4 and ZnMn2O4. Benefiting from the unique structure features, the tube-in-tube hollow nanostructures possess superior electrochemical performances in asymmetric supercapacitors and Li-O2 batteries. PMID:25602640

Peng, Shengjie; Li, Linlin; Hu, Yuxiang; Srinivasan, Madhavi; Cheng, Fangyi; Chen, Jun; Ramakrishna, Seeram

2015-02-24

353

Rare configuration of tautomeric benzimidazolecarboxylate ligands in cadmium(II) and copper(II) coordination polymers  

SciTech Connect

Two Cd(HBimc)-based isomers, [Cd(HBimc{sup N})(HBimc{sup T})(H{sub 2}O)].3.5H{sub 2}O.EtOH (1a.3.5H{sub 2}O.EtOH, H{sub 2}Bimc=1H-benzimidazole-5-carboxylic acid) and [Cd(HBimc{sup N})(HBimc{sup T})(H{sub 2}O)] (1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimc{sup N}){sub 2}(H{sub 2}O)].1/2H{sub 2}O (2.1/2H{sub 2}O, H{sub 2}MBimc=2-methyl-1H-benzimidazole-5-carboxylic acid) and [Cu(HMBimc{sup T}){sub 2}].2THF.H{sub 2}O (3.2THF.H{sub 2}O), were self-assembled from Cd(ClO{sub 4}){sub 2}.6H{sub 2}O/H{sub 2}Bimc and Cu(ClO{sub 4}){sub 2}.6H{sub 2}O/H{sub 2}MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd{sub 2}(HBimc{sup N}){sub 2}-metallocyclic stair and a 1D straight -(Cd-HBimc{sup T}){sub n}- edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D -(Cd-HBimc{sup N}){sub n}- chains and -(Cd-HBimc{sup T}){sub n}- chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like -(Cu-HMBimc{sup N}){sub n}- chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D -(Cu-HMBimc{sup T}){sub n}- chains. Interestingly, a pair of tautomeric HBimc building blocks-normal (N or HBimc{sup N}) and tautomer (T or HBimc{sup T})-is simultaneously included in the structures of 1a and 1b, whilst the N- and T-configured HMBimc building blocks are present as separate entities in Cu species, 2 and 3, respectively. The existence of only a tautomer (T) mode of the benzimidazolecarboxylate-based ligand in a Cu(II) network is observed for the first time. - Graphical abstract: A pair of tautomeric HBimc building blocks (normal (N) and tautomer (T)) is found simultaneously in two Cd(II) networks, whereas, the normal and tautomer modes of HMBimc are present as separate entities in two Cu(II) frameworks. The isolation of a Cu(II) network with only a tautomer (T) mode of the benzimidazolecarboxylate-based ligand is achieved for the first time. Highlights: {yields}Benzimidazolecarboxylates could exhibit normal (N) and tautomer (T) configurations. > A pair of N- and T-modes of HBimc is found simultaneously in two Cd(II) networks. > The N- and T-modes of HMBimc are separately present in two Cu(II) frameworks. > Only a T mode of HMBimc that existed in the structure is observed for the first time.

Wu, Jing-Yun [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Yang, Ciao-Wei; Chen, Hui-Fang [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Jao, Yu-Chen [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Department of Chemical Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Huang, Sheng-Ming [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China); Tsai, Chiitang [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Tseng, Tien-Wen [Department of Chemical Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Lee, Gene-Hsiang; Peng, Shie-Ming [Department of Chemistry, National Taiwan University, Taipei 107, Taiwan (China); Lu, Kuang-Lieh, E-mail: lu@chem.sinica.edu.tw [Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan (China)

2011-07-15

354

Effect of substituent on dimensionality and properties in divalent metal isophthalate coordination polymers with a conformationally flexible dipyridylamide coligand  

NASA Astrophysics Data System (ADS)

Hydrothermal reaction of divalent metal nitrates and 3-pyridylmethylnicotinamide (3-pmna) with either isophthalic acid (H2iph) or 5-nitroisophthalic acid (H2nip) has afforded a series of four coordination polymer solids that were structurally characterized via single-crystal X-ray crystallography. [Ni(iph)(3-pmna)]n (1) and [Cd(iph)(3-pmna)]n (2) both exhibit a {M2(OCO)2} dimer-based 1-D ribbon topology with metal-metal contacts bridged by both ip and 3-pmna ligands. [Ni(nip)(3-pmna)]n (3) has the same topology as its unsubstituted congener 1, showing a null effect on the part of the nip nitro group. On the other hand [Cd(nip)(3-pmna)]n (4) exhibits a {Cd2O2} dimer-based 2-D (4,4) layer topology, a rare example of the nitro group imposing a higher dimensionality in the resulting coordination polymer. While 2 showed strong blue-violet luminescence, quenching mechanisms due to the nitro group rendered 4 non-luminescent. Thermal properties of these new materials are also investigated.

Torres Salgado, Maria D.; LaDuca, Robert L.

2015-01-01

355

Syntheses, crystal structure and properties of two novel coordination polymers with the flexible tetrazole-1-acetic acid (Htza)  

SciTech Connect

Two new coordination polymers, [Ag(tza)]{sub {infinity}} (1) (Htza=tetrazole-1-acetic acid) and [Cu(tza){sub 2}]{sub {infinity}} (2) have been prepared at room temperature and characterized by X-ray crystallography, IR, UV-vis, fluorescence spectra and magnetism analysis. Compound 1 exhibits extended helical chains through bridging ligand tza. The Ag{center_dot}{center_dot}{center_dot}Ag interactions between the adjacent chains form a 3-D framework featuring the extended tza-connected Ag chains that obviously affect the photoluminescent property. Compound 2 features undulated layered structure with hourglass-shaped [Cu{sub 4}(tza){sub 4}] as subunits with the weak ferromagnetic interactions between Cu(II) ions, which are further stabilized by inter-lamellar C-H{center_dot}{center_dot}{center_dot}O hydrogen bonds in the resulting 3-D supramolecular framework. - Graphical abstract: Two novel coordination polymers, [Ag(tza)]{sub {infinity}} (1) and [Cu(tza){sub 2{infinity}} (2) have been prepared and characterized. Compound 1 features extended double-stranded helical chains. Compound 2 features undulated layered structure with hourglass-shaped [Cu{sub 4}(tza){sub 4}] as subunits with the weak ferromagnetic interactions between Cu(II) ions.

Dong Wenwen; Zhao Jun [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Li [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)], E-mail: xli@fjirsm.ac.cn

2008-05-15

356

Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties  

SciTech Connect

A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln{sub 2}(Hdpp){sub 2}(dpp){sub 2}]{sub n}Ln=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H{sub 2}dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1–5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 4+} basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions. - Graphical abstract: A new family of lanthanide-organic frameworks incorporating multi-donor twisted ligand has been fabricated successfully, and has been characterized systematically. The complexes 1–5 are isostructural, and all feather three dimensional (3D) frameworks based on the interconnection of 1D double stride chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 2+} basic carboxylate as secondary building unit (SBU). Display Omitted - Highlights: • New family of lanthanide–organic coordination polymers incorporating multifunctional N-hetrocyclic dicarboxylate ligand has been fabricated. • They have been characterized systematically. • They all feather three dimensional frameworks based on the binuclear moiety of [Ln{sub 2}(Hdpp){sub 2}]{sup 2+}. • The Eu(III) and Dy(III) analogues exhibit intense photoluminescence.

Feng, Xun [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Liu, Lang [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Wang, Li-Ya, E-mail: wlya@lynu.edu.cn [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang 473601 (China); Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Ng, Seik-Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 80203 (Saudi Arabia)

2013-10-15

357

Soft coordination supramolecular polymers: novel materials for dual electro-Yawei Liang,{a  

E-print Network

to the dynamic nature of coordinating bonds.8,11 In the past decade, various SCSPs of transition and rare earth metals with judicious ligands have been achieved.12,13 It is expected that these metal-containing novel

Huang, Jianbin

358

Copper(II)-lanthanide(III) coordination polymers constructed from pyridine-2,5-dicarboxylic acid: Preparation, crystal structure and photoluminescence  

SciTech Connect

A series of 3d-4f heterometallic coordination polymers, formulated as {l_brace} [Cu{sub 3}Ln{sub 2}(pydc){sub 6}(H{sub 2}O){sub 12}]{center_dot}4H{sub 2}O{r_brace} {sub n} [Ln=Tb (1), Eu (2), Dy (3), Ho (4), Lu (5)], {l_brace} [CuNd{sub 2}(pydc){sub 4}(H{sub 2}O){sub 3}]{center_dot}H{sub 2}O{r_brace} {sub n} (6) and {l_brace} [Cu{sub 3}Pr{sub 2}(pydc){sub 6}(H{sub 2}O){sub 13}]{center_dot}4H{sub 2}O{r_brace} {sub n} (7) (where H{sub 2}pydc=pyridine-2,5-dicarboxylic acid), have been hydrothermally prepared by reactions of H{sub 2}pydc ligand with lanthanide ions in the presence of Cu(II) ion. X-ray crystal structure analysis reveals that these compounds exhibit rich structural chemistry. 1-5 are isomorphous and present a two-dimensional network constructed from Ln{sub 2}Cu{sub 2}L{sub 2}(H{sub 2}O){sub 2} SBU rings and CuL{sub 2}(H{sub 2}O) building blocks. In 6, two-dimensional ladder-like layers based on Nd(III) belts and CuL{sub 2}O{sub 2} units are assembled by H{sub 2}pydc ligands into a three-dimensional open framework. Polymer 7 displays a two-dimensional wave-like layer structure containing two distinct ring units, in which a new coordination mode of the pydc{sup 2-} ligand is observed. The results indicate that the coordination flexibility of the pydc{sup 2-} ligand and lanthanide contraction effect play cooperative roles in the formation of coordination polymers with different polymeric architectures. Compounds 1-2 exhibit intense green and red luminescence emission characteristics of Tb(III) and Eu(III), respectively. Furthermore, elemental analyses (EA), infrared spectra (IR) and thermogravimetric analyses (TGA) of these compounds were also studied. - Graphical abstract: Seven 3d-4f heterometallic coordination polymers were synthesized by reactions of H{sub 2}pydc with lanthanide metal ions in the presence of Cu{sup 2+}, the effects of Cu{sup 2+} on the structures and photoluminescent properties of Ln-pydc{sup 2-} systems were investigated. Highlights: Black-Right-Pointing-Pointer Seven 3d-4f heterometallic compounds have been prepared and characterized. Black-Right-Pointing-Pointer 1-5 and 7 are constructed from Ln{sub 2}Cu{sub 2}L{sub 2}(H{sub 2}O){sub 2} rings and CuL{sub 2}(H{sub 2}O) building blocks. Black-Right-Pointing-Pointer One new coordination mode of the pydc{sup 2-} ligand is first observed. Black-Right-Pointing-Pointer 1-2 exhibit intense characteristic luminescence emission spectra of lanthanide ions.

Xia Zhengqiang; Wei Qing [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (China); Chen Sanping, E-mail: sanpingchen@126.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (China); Feng Xinming; Xie Gang [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (China); Qiao Chengfang [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (China); Department of Chemistry and Chemical Engineering, Shangluo University, Shangluo 726000 (China); Zhang Guochun [Department of Chemistry and Chemical Engineering, Shangluo University, Shangluo 726000 (China); Gao Shengli [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (China)

2013-01-15

359

Modular, homochiral, porous coordination polymers: rational design, enantioselective guest exchange sorption and ab initio calculations of host-guest interactions.  

PubMed

Two new, homochiral, porous metal-organic coordination polymers [Zn(2)(ndc){(R)-man}(dmf)]?3DMF and [Zn(2)(bpdc){(R)-man}(dmf)]?2DMF (ndc=2,6-naphthalenedicarboxylate; bpdc=4,4'-biphenyldicarboxylate; man=mandelate; dmf=N,N'-dimethylformamide) have been synthesized by heating Zn(II) nitrate, H(2)ndc or H(2)bpdc and chiral (R)-mandelic acid (H(2)man) in DMF. The colorless crystals were obtained and their structures were established by single-crystal X-ray diffraction. These isoreticular structures share the same topological features as the previously reported zinc(II) terephthalate lactate [Zn(2)(bdc){(S)-lac}(dmf)]?DMF framework, but have larger pores and opposite absolute configuration of the chiral centers. The enhanced pores size results in differing stereoselective sorption properties: the new metal-organic frameworks effectively and stereoselectively (ee up to 62?%) accommodate bulkier guest molecules (alkyl aryl sulfoxides) than the parent [Zn(2)(bdc){(S)-lac}(dmf)]?DMF, while the latter demonstrates decent enantioselectivity toward precursor of chiral anticancer drug sulforaphane, CH(3)SO(CH(2))(4)OH. The new homochiral porous metal-organic coordination polymers are capable of catalyzing a highly selective oxidation of bulkier sulfides (2-NaphSMe (2-C(10)H(7)SMe) and PhSCH(2)Ph) that could not be achieved by the smaller-pore [Zn(2)(bdc){(S)-lac}(dmf)]?DMF. The sorption of different guest molecules (both R and S isomers) into the chiral pores of [Zn(2)(bdc){(S)-lac}(dmf)]?DMF was modeled by using ab initio calculations that provided a qualitative explanation for the observed sorption enantioselectivity. The high stereo-preference is accounted for by the presence of coordinated inner-pore DMF molecule that forms a weak C-H...O bond between the DMF methyl group and the (S)-PhSOCH(3) sulfinyl group. PMID:20730747

Dybtsev, Danil N; Yutkin, Maxim P; Samsonenko, Denis G; Fedin, Vladimir P; Nuzhdin, Alexey L; Bezrukov, Andrey A; Bryliakov, Konstantin P; Talsi, Evgeniy P; Belosludov, Rodion V; Mizuseki, Hiroshi; Kawazoe, Yoshiyuki; Subbotin, Oleg S; Belosludov, Vladimir R

2010-09-10

360

An adaptive grid algorithm for one-dimensional nonlinear equations  

NASA Technical Reports Server (NTRS)

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

Gutierrez, William E.; Hills, Richard G.

1990-01-01

361

One dimensional scattering of a two body interacting system by an infinite wall  

E-print Network

The one-dimensional scattering of a two body interacting system by an infinite wall is studied in a quantum-mechanical framework. This problem contains some of the dynamical features present in the collision of atomic, molecular and nuclear systems. The scattering problem is solved exactly, for the case of a harmonic interaction between the fragments. The exact result is used to assess the validity of two different approximations to the scattering process. The adiabatic approximation, which considers that the relative co-ordinate is frozen during the scattering process, is found to be inadequate for this problem. The uncorrelated scattering approximation, which neglects the correlation between the fragments, gives results in accordance with the exact calculations when the scattering energy is high compared to the oscillator parameter.

A. M. Moro; J. A. Caballero; J. Gomez-Camacho

2010-10-24

362

Moment-Preserving SN Discretizations for the One-Dimensional Fokker-Planck Equation  

SciTech Connect

The Fokker-Planck equation: (1) Describes the transport and interactions of charged particles, (2) Many small-angle scattering collisions, (3) Asymptotic limit of the Boltzmann equation (Pomraning, 1992), and (4) The Boltzmann collision operator becomes the angular Laplacian. SN angular discretization: (1) Angular flux is collocated at the SN quadrature points, (2) The second-order derivatives in the Laplacian term must be discretized, and (3) Weighted finite-difference method preserves zeroth and first moments (Morel, 1985). Moment-preserving methods: (1) Collocate the Fokker-Planck operator at the SN quadrature points, (2) Develop several related and/or equivalent methods, and (3) Motivated by discretizations for the angular derivative appearing in the transport equation in one-dimensional spherical coordinates.

Warsa, James S. [Los Alamos National Laboratory; Prinja, Anil K. [Los Alamos National Laboratory

2012-06-14

363

Two Ag(I) coordination polymers derived from melamine and dicarboxylates: Syntheses, crystal structures and thermal stabilities  

NASA Astrophysics Data System (ADS)

Two mixed-ligand Ag(I) coordination polymers (CPs), [(NH 4)Ag 3(MA) 2(suc) 2] n ( 1), [Ag 2(MA) 2(adip)·CH 3OH·H 2O] n ( 2), (where MA = melamine, H 2suc = succinic acid, H 2adip = adipic acid) have been synthesized and structurally characterized by element analysis, IR and X-ray single-crystal diffraction. The CP 1 is a three-dimensional (3D) framework in which the MA acts as a tridentate ligand and suc 2- anion shows three types of coordination modes. Each Ag(I) ion acts as a 4-connected node to generate three- and six-membered cycles, as a result, the network can be simplified to be an overall multi-layered Kagomé topology. The CP 2 is a 2D single-layer structure constructed by tridentate MA ligands and adip 2- anions. The adjacent single-layers are inter-linked to form a double-layer 2D structure through the Ag⋯Ag interactions. Two CPs structurally vary from 2D sheet to 3D framework, which indicates that the different dicarboxylates and coordination modes of MA ligand have significant influence on the final structures. Moreover, the thermal stabilities of them were also discussed.

Li, Yun-Hua; Sun, Di; Luo, Geng-Geng; Liu, Fu-Jing; Hao, Hong-Jun; Wen, Yi-Mei; Zhao, Yang; Huang, Rong-Bin; Zheng, Lan-Sun

2011-08-01

364

The Effect of pH on the Dimensionality of Coordination Polymers Long Pan, Thomas Frydel, Michelle B. Sander, Xiaoying Huang, and Jing Li*  

E-print Network

with 3,5-pyrazoledicarboxylic acid (H3pdc) yielded seven new compounds. At a lower pH level three one. This compound contains [2+2] metallomacrocycles. At higher pH levels (pH ) 4-6), the three-dimensional polymersThe Effect of pH on the Dimensionality of Coordination Polymers Long Pan, Thomas Frydel, Michelle B

Li, Jing

365

One-dimensional surface phonon polaritons in boron nitride nanotubes  

NASA Astrophysics Data System (ADS)

Surface polaritons, which are electromagnetic waves coupled to material charge oscillations, have enabled applications in concentrating, guiding and harvesting optical energy below the diffraction limit. Surface plasmon polaritons involve oscillations of electrons and are accessible in noble metals at visible and near-infrared wavelengths, whereas surface phonon polaritons (SPhPs) rely on phonon resonances in polar materials, and are active in the mid-infrared. Noble metal surface plasmon polaritons have limited applications in the mid-infrared. SPhPs at flat interfaces normally possess long polariton wavelengths and provide modest field confinement/enhancement. Here we demonstrate propagating SPhPs in a one-dimensional material consisting of a boron nitride nanotube at mid-infrared wavelengths. The observed SPhP exhibits high field confinement and enhancement, and a very high effective index (neff~70). We show that the modal and propagation length characteristics of the SPhPs may be controlled through the nanotube size and the supporting substrates, enabling mid-infrared applications.

Xu, Xiaoji G.; Ghamsari, Behnood G.; Jiang, Jian-Hua; Gilburd, Leonid; Andreev, Gregory O.; Zhi, Chunyi; Bando, Yoshio; Golberg, Dmitri; Berini, Pierre; Walker, Gilbert C.

2014-08-01

366

Moving solitons in a one-dimensional fermionic superfluid  

NASA Astrophysics Data System (ADS)

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

Efimkin, Dmitry K.; Galitski, Victor

2015-02-01

367

Characterization of Thermal Transport in One-dimensional Solid Materials.  

PubMed

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

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

2014-01-01

368

Validation and Comparison of One-Dimensional Graound Motion Methodologies  

SciTech Connect

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

B. Darragh; W. Silva; N. Gregor

2006-06-28

369

Bloch oscillations in a one-dimensional organic lattice  

NASA Astrophysics Data System (ADS)

We present a model study on the dynamics of electron transport of a dissociated polaron under a strong uniform electric field in a one-dimensional organic lattice. The simulations are performed within the framework of the Su-Schrieffer-Heeger model coupled by a Newtonian equation of motion with a nonadiabatic evolution method. It is found that the dissociated polaron propagates in the form of a freelike electron and performs spatial Bloch oscillations (BO’s). In contrast to normal BO’s in a rigid lattice, the mean displacement of the oscillating electron will have a net forward movement in the direction of the electric field, which is dependent on the strong electron-lattice couplings in the organic lattice. It is also found that a transient polaron forms at the end of each period of BO’s, accompanying the appearance of discrete polaron levels in the gap of the band. The effects of electron-electron interactions and bond disorder in the organic lattice are briefly discussed.

Li, Yuan; Liu, Xiao-Jing; Fu, Ji-Yong; Liu, De-Sheng; Xie, Shi-Jie; Mei, Liang-Mo

2006-11-01

370

Stochastic One-Dimensional Lorentz Gas on a Lattice  

NASA Astrophysics Data System (ADS)

We study a one-dimensional stochastic Lorentz gas where a light particle moves in a fixed array of nonidentical random scatterers arranged in a lattice. Each scatterer is characterized by a random transmission/reflection coefficient. We consider the case when the transmission coefficients of the scatterers are independent identically distributed random variables. A symbolic program is presented which generates the exact velocity autocorrelation function (VACF) in terms of the moments of the transmission coefficients. The VACF is found for different types of disorder for times up to 20 collision times. We then consider a specific type of disorder: a two-state Lorentz gas in which two types of scatterers are arranged randomly in a lattice. Then a lattice point is occupied by a scatterer whose transmission coefficient is ? with probability p or ?+? with probability 1- p. A perturbation expansion with respect to ? is derived. The ?2 term in this expansion shows that the VACF oscillates with time, the period of oscillation being twice the time of flight from one scatterer to its nearest neighbor. The coarse-grained VACF decays for long times like t -3/2, which is similar to the decay of the VACF of the random Lorentz gas with a single type of scatterer. The perturbation results and the exact ones (found up to 20 collision times) show good agreement.

Barkai, E.; Fleurov, V.

1999-07-01

371

A one-dimensional liquid of fermions with tunable spin  

NASA Astrophysics Data System (ADS)

Correlations in systems with spin degree of freedom are at the heart of fundamental phenomena, ranging from magnetism to superconductivity. The effects of correlations depend strongly on dimensionality, a striking example being one-dimensional (1D) electronic systems, extensively studied theoretically over the past fifty years. However, the experimental investigation of the role of spin multiplicity in 1D fermions--and especially for more than two spin components--is still lacking. Here we report on the realization of 1D, strongly correlated liquids of ultracold fermions interacting repulsively within SU(N) symmetry, with a tunable number N of spin components. We observe that static and dynamic properties of the system deviate from those of ideal fermions and, for N > 2, from those of a spin-1/2 Luttinger liquid. In the large-N limit, the system exhibits properties of a bosonic spinless liquid. Our results provide a testing ground for many-body theories and may lead to the observation of fundamental 1D effects.

Pagano, Guido; Mancini, Marco; Cappellini, Giacomo; Lombardi, Pietro; Schäfer, Florian; Hu, Hui; Liu, Xia-Ji; Catani, Jacopo; Sias, Carlo; Inguscio, Massimo; Fallani, Leonardo

2014-03-01

372

Digital noise generators using one-dimensional chaotic maps  

SciTech Connect

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

Martínez-Ñonthe, J. A; Palacios-Luengas, L.; Cruz-Irisson, M.; Vazquez Medina, R. [Instituto Politécnico Nacional, ESIME-Culhuacan, Santa Ana 1000, 04430, D.F. (Mexico); Díaz Méndez, J. A. [Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Tonantzintla, Puebla (Mexico)

2014-05-15

373

Traveling waves in a one-dimensional model of hemodynamics  

NASA Astrophysics Data System (ADS)

We consider a one-dimensional model of hemodynamics—blood flow in the blood vessels—which is based on the Navier-Stokes equations averaged over the cross section of the vessel, and conjugate with a linear or nonlinear model for the elastic wall of the vessel. The objective is to study traveling wave solutions using this model. For such solutions, the system of partial differential equations reduces to an ordinary differential equation of the fourth order. The only singular point of the corresponding system of differential equations is found. It is established that at the singular point, the linearization matrix of the system has real or complex roots for different values of the parameters of the problem. With a special choice of the parameters, it has four complex conjugate roots with a nonzero real part or purely imaginary roots. For this case, the effect of the model parameter corresponding to the viscoelastic response of the vessel wall on the solution is investigated. Numerical experiments are performed to verify and analyze the results, and various modes of blood movement are discussed.

Barlukova, A. M.; Cherevko, A. A.; Chupakhin, A. P.

2014-11-01

374

Fractal spectra in generalized Fibonacci one-dimensional magnonic quasicrystals  

NASA Astrophysics Data System (ADS)

In this work we carry out a theoretical analysis of the spectra of magnons in quasiperiodic magnonic crystals arranged in accordance with generalized Fibonacci sequences in the exchange regime, by using a model based on a transfer-matrix method together random-phase approximation (RPA). The generalized Fibonacci sequences are characterized by an irrational parameter ?(p,q), which rules the physical properties of the system. We discussed the magnonic fractal spectra for first three generalizations, i.e., silver, bronze and nickel mean. By varying the generation number, we have found that the fragmentation process of allowed bands makes possible the emergence of new allowed magnonic bulk bands in spectra regions that were magnonic band gaps before, such as which occurs in doped semiconductor devices. This interesting property arises in one-dimensional magnonic quasicrystals fabricated in accordance to quasiperiodic sequences, without the need to introduce some deferent atomic layer or defect in the system. We also make a qualitative and quantitative investigations on these magnonic spectra by analyzing the distribution and magnitude of allowed bulk bands in function of the generalized Fibonacci number Fn and as well as how they scale as a function of the number of generations of the sequences, respectively.

Costa, C. H. O.; Vasconcelos, M. S.; Barbosa, P. H. R.; Barbosa Filho, F. F.

2012-07-01

375

Statistical properties of one-dimensional parametrically kicked Hamilton systems.  

PubMed

We study the one-dimensional Hamiltonian systems and their statistical behavior, assuming the initial microcanonical distribution and describing its change under a parametric kick, which by definition means a discontinuous jump of a control parameter of the system. Following a previous work by Papamikos and Robnik [J. Phys. A: Math. Theor. 44, 315102 (2011)], we specifically analyze the change of the adiabatic invariant (the action) of the system under a parametric kick: A conjecture has been put forward that the change of the action at the mean energy always increases, which means, for the given statistical ensemble, that the Gibbs entropy in the mean increases. By means of a detailed analysis of a great number of case studies, we show that the conjecture largely is satisfied, except if either the potential is not smooth enough or if the energy is too close to a stationary point of the potential (separatrix in the phase space). Very fast changes in a time-dependent system quite generally can be well described by such a picture and by the approximation of a parametric kick, if the change of the parameter is sufficiently fast and takes place on the time scale of less than one oscillation period. We discuss our work in the context of the statistical mechanics in the sense of Gibbs. PMID:25019871

Andresas, Dimitris; Batisti?, Benjamin; Robnik, Marko

2014-06-01

376

Is there hope for spintronics in one dimensional realistic systems?  

NASA Astrophysics Data System (ADS)

The use of the electron spin as the ultimate logic bit can lead to a novel way of thinking about information flow. At the same time graphene, a gapless semiconductor, has been the subject of intense research due to its fundamental properties and its potential application in electronics. Defects are usually seen as having deleterious effects on the spin polarization of devices and thus they would tend to hinder the applicability of spintronics in realistic devices. Here we use a ab initio methods to simulate the electronic transport properties of graphene nanoribbons up to 450 nm long containing a large number of randomly distributed impurities. We will demonstrate that it is possible to obtain perfect spin selectivity in these nanoribbons which can be explained in terms of different localization lengths for each spin channel. This together with the well know exponential dependence of the conductance on the length of the device leads to a new mechanism for the spin filtering effect that is in fact driven by disorder. Furthermore, we demonstrate that this is an effect that does not depend on the underlying system itself and could be observed in carbon nanotubes and nanowires or any other one-dimensional device.

Rocha, Alexandre; Martins, Thiago; Fazzio, Adalberto; da Silva, Antônio J. R.

2010-03-01

377

Characterization of Thermal Transport in One-dimensional Solid Materials  

PubMed Central

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

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

2014-01-01

378

A one-dimensional model of Nucleosome distribution in DNA  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

379

Dynamics in the one-dimensional extended ionic Hubbard model  

NASA Astrophysics Data System (ADS)

We investigate single-particle spectral densities and dynamical charge and spin structure factors of the one-dimensional extended ionic Hubbard model in the band insulator regime by using the perturbative continuous unitary transformations method. The one-body staggered potential is considered as the unperturbed part and the hopping term, on-site electron-electron interaction, and the nearest-neighbor repulsive interaction are treated as the perturbations. The excitation spectrum of this model was determined in a previous work (Hafez and Jafari 2010 Eur. Phys. J. B 78 323). It was shown that when the intersite interaction is off, there are two antibound state modes and one bound state mode in the singlet channel and two bound state modes in the triplet channel, while for finite values of intersite interaction two bound state modes were found in each channel. Our results for dynamical charge and spin structure factors indicate that only one of two bound/antibound state modes can be probed by electron-energy-loss spectroscopy and inelastic neutron scattering experiments.

Hafez, Mohsen; Abolhassani, M. R.

2011-06-01

380

Using the NASA GRC Sectored-One-Dimensional Combustor Simulation  

NASA Technical Reports Server (NTRS)

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

Paxson, Daniel E.; Mehta, Vishal R.

2014-01-01

381

One-dimensional surface phonon polaritons in boron nitride nanotubes.  

PubMed

Surface polaritons, which are electromagnetic waves coupled to material charge oscillations, have enabled applications in concentrating, guiding and harvesting optical energy below the diffraction limit. Surface plasmon polaritons involve oscillations of electrons and are accessible in noble metals at visible and near-infrared wavelengths, whereas surface phonon polaritons (SPhPs) rely on phonon resonances in polar materials, and are active in the mid-infrared. Noble metal surface plasmon polaritons have limited applications in the mid-infrared. SPhPs at flat interfaces normally possess long polariton wavelengths and provide modest field confinement/enhancement. Here we demonstrate propagating SPhPs in a one-dimensional material consisting of a boron nitride nanotube at mid-infrared wavelengths. The observed SPhP exhibits high field confinement and enhancement, and a very high effective index (neff~70). We show that the modal and propagation length characteristics of the SPhPs may be controlled through the nanotube size and the supporting substrates, enabling mid-infrared applications. PMID:25154586

Xu, Xiaoji G; Ghamsari, Behnood G; Jiang, Jian-Hua; Gilburd, Leonid; Andreev, Gregory O; Zhi, Chunyi; Bando, Yoshio; Golberg, Dmitri; Berini, Pierre; Walker, Gilbert C

2014-01-01

382

Dynamical spin structure factor of one-dimensional interacting fermions  

NASA Astrophysics Data System (ADS)

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

Zyuzin, Vladimir A.; Maslov, Dmitrii L.

2015-02-01

383

Fractal analysis in a one-dimensional universe  

NASA Astrophysics Data System (ADS)

While the universe we observe today exhibits local filament-like structures, with stellar clusters and large voids between them, the primordial universe is believed to have been nearly homogeneous with slight variations in matter density. To understand how the observed hierarchical structure was formed, researchers have developed a one-dimensional analogue of the universe that can simulate the evolution of a large number of matter particles. Investigations to date demonstrate that this model reveals structure formation that shares essential features with the three-dimensional observations. In the present work, we have expanded on this concept to include two species of matter, specifically dark matter and luminous matter. In our simulation, luminous matter is treated in a way that loses energy in interaction. The results of the simulations clearly show the formation of a Cantor set like multifractal pattern over time. In contrast with most earlier studies, mass-oriented methods for computing multifractal dimensions were applied to analyze the bottom-up structure formation.

Shiozawa, Yui

384

One-dimensional flows of an imperfect diatomic gas  

NASA Technical Reports Server (NTRS)

With the assumptions that Berthelot's equation of state accounts for molecular size and intermolecular force effects, and that changes in the vibrational heat capacities are given by a Planck term, expressions are developed for analyzing one-dimensional flows of a diatomic gas. The special cases of flow through normal and oblique shocks in free air at sea level are investigated. It is found that up to a Mach number 10 pressure ratio across a normal shock differs by less than 6 percent from its ideal gas value; whereas at Mach numbers above 4 the temperature rise is considerable below and hence the density rise is well above that predicted assuming ideal gas behavior. It is further shown that only the caloric imperfection in air has an appreciable effect on the pressures developed in the shock process considered. The effects of gaseous imperfections on oblique shock-flows are studied from the standpoint of their influence on the life and pressure drag of a flat plate operating at Mach numbers of 10 and 20. The influence is found to be small. (author)

1959-01-01

385

Weak lasing in one-dimensional polariton superlattices.  

PubMed

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

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

2015-03-31

386

Normal coordinate treatment and conformational analysis of a new type of inorganic polymers: Poly(dichlorophosphazene)  

NASA Astrophysics Data System (ADS)

A conformational analysis and a calculation of the normal modes were performed for phosphorylphosphazene, OP 2NCl 5 and OP 3N 2Cl 7 as a first step toward poly(dichloro)phosphazene polymers. The agreement with experience is good and indicates a tendency to cis-trans conformation of the PNPN chain.

Bougeard, D.; Bremard, C.; De Jaeger, R.; Deroubaix, A.; Lemmouchi, Y.

1992-03-01

387

The structures and luminescence properties of lanthanide (Ln = Sm, Eu and Tb) metal-organic coordination polymers based on 5-(2-hydroxyethoxy)isophthalate ligand  

NASA Astrophysics Data System (ADS)

Three unreported isomorphous Ln-containing metal-organic coordination polymeric complexes {LnL(HL)?(H2O)2}n (Ln = Sm (1), Eu (2) and Tb (3), CCDC 971815-971817) were synthesized based on 5-(2-hydroxyethoxy) isophthalic acid (H2L) under hydrothermal conditions. The obtained coordination polymers were characterized by IR, elemental analysis, thermal analysis and X-ray diffraction In solid state, these polymers featured 3-D supramolecular structures constructed by 2-D sheets through H-bonds. Investigation of photoluminescence properties of H2L and 1-3 showed all of them exhibited intense fluorescent emissions in the solid state at room temperature.

Wang, Peng; Zhang, Yu-Jie; Qin, Jie; Chen, Yong; Zhao, Ying

2015-03-01

388

Six Zn(ii) and Cd(ii) coordination polymers assembled from a similar binuclear building unit: tunable structures and luminescence properties.  

PubMed

Six Zn(ii) and Cd(ii) coordination polymers were constructed by treating a 2-substituted 8-hydroxyquinolinate ligand containing a pyridyl group with zinc or cadmium salts, and characterized by a variety of techniques. Interestingly, based on a similar binuclear Zn(ii) or Cd(ii) building unit, the supramolecular structures of the six coordination polymers () exhibit an unprecedented structural diversification due to the different choices of metal salts. and represent a novel 2D framework containing 1D infinite right- and left-handed helical chains. and are 2D coordination frameworks based on binuclear Cd(ii) building units. For and , the L ligands can bridge binuclear building units forming a 1D infinite chain. Interestingly, the adjacent Cd2O2 planes of the 1D chain in are in parallel with each other, while the dihedral angle between the two Zn2O2 planes in is 83.43°. Photoluminescence properties revealed that the six coordination polymers exhibit redshifted emission maximum compared with the free ligand HL, which can be ascribed to an increased conformational rigidity and the fabrication of coplanar binuclear building units M2L2 in . Coordination polymers also display distinct fluorescence lifetimes and quantum yields because of their different metal centers and supramolecular structures. PMID:25601297

Zhang, Liyan; Rong, Lulu; Hu, Guoli; Jin, Suo; Jia, Wei-Guo; Liu, Ji; Yuan, Guozan

2015-04-01

389

A string reaction coordinate for the folding of a polymer chain  

E-print Network

We investigate the crystallization mechanism of a single, flexible homopolymer chain with short range attractions. For a sufficiently narrow attractive well, the system undergoes a first-order like freezing transition from an expanded disordered coil to a compact crystalline state. Based on a maximum likelihood analysis of committor values computed for configurations obtained by Wang-Landau sampling, we construct a non-linear string reaction coordinate for the coil-to-crystal transition. In contrast to a linear reaction coordinate, the string reaction coordinate captures the effect of different degrees of freedom controlling different stages of the transition. Our analysis indicates that a combination of the energy and the global crystallinity parameter Q6 provide the most accurate measure for the progress of the transition. While the crystallinity parameter Q6 is most relevant in the initial stages of the crystallization, the later stages are dominated by a decrease in the potential energy.

Leitold, Christian; Dellago, Christoph

2015-01-01

390

A string reaction coordinate for the folding of a polymer chain  

E-print Network

We investigate the crystallization mechanism of a single, flexible homopolymer chain with short range attractions. For a sufficiently narrow attractive well, the system undergoes a first-order like freezing transition from an expanded disordered coil to a compact crystalline state. Based on a maximum likelihood analysis of committor values computed for configurations obtained by Wang-Landau sampling, we construct a non-linear string reaction coordinate for the coil-to-crystal transition. In contrast to a linear reaction coordinate, the string reaction coordinate captures the effect of different degrees of freedom controlling different stages of the transition. Our analysis indicates that a combination of the energy and the global crystallinity parameter Q6 provide the most accurate measure for the progress of the transition. While the crystallinity parameter Q6 is most relevant in the initial stages of the crystallization, the later stages are dominated by a decrease in the potential energy.

Christian Leitold; Wolfgang Lechner; Christoph Dellago

2015-01-16

391

Gas adsorption/separation properties of metal directed self-assembly of two coordination polymers with 5-nitroisophthalate  

SciTech Connect

Two new coordination polymers, namely, [Co(µ-nip)(µ-bpe)]{sub n} (1) and [Zn(µ-nip)(µ-bpe)]{sub n} (2) (nip: 5-nitroisophthalate, bpe: 1,2-bis(4-pyridyl)ethane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermal analysis. Moreover, atomically detailed simulation studies of complex 2 for CO{sub 2}/CH{sub 4} adsorption and separation were performed. Complex 1 consists of two dimensional (2D) (4,4) grid networks with the point symbol of 4{sup 4}.6{sup 2}. Complex 2 exhibits a 3-fold interpenetrating 3D framework with 6{sup 5}.8-dmp topology. Thermal properties of the complexes showed that both complexes were stable over 320 °C. Simulation studies demonstrated that complex 2 can separate CO{sub 2} from CH{sub 4} at low pressures at 273 K. - Graphical abstract: In this study, two new coordination polymers, namely, [Co(µ-nip)(µ-bpe)]{sub n} (1) and [Zn(µ-nip)(µ-bpe)]{sub n} (2) (nip: 5-nitroisophthalate, bpe: 1,2-bis(4-pyridyl)ethane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermal analysis. Moreover, atomically detailed simulation studies of complex 2 for CO{sub 2}/CH{sub 4} adsorption and separation were performed. Complex 1 consists of two dimensional (2D) (4,4) grid networks with the point symbol of 4{sup 4}.6{sup 2}. Complex 2 exhibits a 3-fold interpenetrating 3D framework with 6{sup 5}.8-dmp topology. Simulation studies demonstrated that complex 2 can separate CO{sub 2} from CH{sub 4} at low pressures at 273 K. Display Omitted - Highlights: • Two new coordination polymers with 5-nitroisophthalate and 1,2-bis(4-pyridyl)ethane. • Atomically detailed simulation studies of the complexes. • Complex 2 can be proposed as molecular sieve to separate CO{sub 2} from CH{sub 4} at low pressures.

Ar?c?, Mürsel [Department of Chemistry, Faculty of Arts and Sciences, Eski?ehir Osmangazi University, 26480 Eski?ehir (Turkey); Ye?ilel, Okan Zafer, E-mail: yesilel@ogu.edu.tr [Department of Chemistry, Faculty of Arts and Sciences, Eski?ehir Osmangazi University, 26480 Eski?ehir (Turkey); Keskin, Seda [Department of Chemical and Biological Engineering, Koç University, ?stanbul (Turkey); ?ahin, Onur [Scientific and Technological Research Application and Research Center, Sinop University, 57010 Sinop (Turkey)

2014-02-15

392

A self-assembled non-interpenetrating cubic diamondoid coordination polymer of hexamine with linear dicopper spacer: Structural and magnetic studies  

Microsoft Academic Search

Structural characterization of a new self assembled coordination polymer of CuII, hexamine (hmt) and benzoate (OBz), [Cu4(OBz)8(hmt)]n (1), reveals that it is a cubic non-interpenetrating diamondoid network formed by the coordination of the ?4-hmt ligand to a linear [Cu2(OBz)4] spacer. The magnetic study reveals that the Cu(II) ions are antiferromagnetically coupled (J=?323.5cm?1) through the syn–syn carboxylate bridges.

Shantanu Hazra; Biswarup Sarkar; Subrata Naiya; Michael G. B. Drew; Joan Ribas; Carmen Diaz; Ashutosh Ghosh

2011-01-01

393

Aromatic N-oxides in construction of different carboxylate coordination polymers of zinc(II), cadmium(II) and mercury(II)  

NASA Astrophysics Data System (ADS)

The coordination polymers [Zn(C 6H 5COO) 2(PNO)] n ( 1), [Zn 2(C 6H 5COO) 4(4,4'-BPNO)] n ( 2), [Zn 4(C 6H 4C 2O 4) 4(4,4'-BPNO) 2(H 2O) 5] n· nH 2O ( 3), [Cd(C 6H 5COO) 2(PNO)] n ( 4), [Cd 3(C 6H 5COO) 6(4,4'-BPNO) 2] n·2 nH 2O ( 5), [Cd(C 6H 4C 2O 4)(4,4'-BPNO)(H 2O)] n ( 6) and [Hg(C 6H 5COO) 2(4,4'-BPNO) 2] n ( 7), (where PNO = pyridine N-oxide, 4,4'-BPNO = 4,4'-bipyridyl- N,N'-dioxide) are synthesized and structurally characterized. The structures of these coordination polymers exhibit mononuclear to trinuclear nodes built by ligation of carboxylate to metal ions connected by N-oxide ligands. Pyridine N-oxide interconnects metal nodes by acting as ? 2-bridging ligand in complexes 1, and 4. In the linear coordination polymer 2, the paddle wheel structure of zinc(II) benzoate units are interconnected by 4,4'-bipyridyl- N,N'-dioxide which acts as a bidentate spacer ligand adopting a trans ? 2-? 1 : ? 1 coordination mode. The polymeric structure of 3 formed by terephthalate and 4,4'-bipyridyl- N,N'-dioxide with zinc(II) contains self-assembled dinuclear Zn 2O 2 type of carboxylate cores, with 4,4'-bipyridyl- N,N'-dioxide coordinating through cis ? 2-? 1 : ? 1 coordination mode. The cadmium coordination polymer 5, comprising of 4,4'-bipyridyl- N,N'-dioxide and benzoate, has trinuclear cadmium benzoate cores wherein the terminal cadmium ions are interconnected by monodentate 4,4'-bipyridyl- N,N'-dioxide bridges. The coordination polymer 6 comprises of mononuclear cadmium nodes independently bridged by terephthalate and 4,4'-bipyridyl- N,N'-dioxide thereby leading to a 3-fold interpenetrated three dimensional network. Double helical polymeric structure is observed in the coordination polymer 7 derived from mononuclear mercury(II) benzoate nodes bridged by 4,4'-bipyridyl- N,N'-dioxide with cis ? 2-? 1 : ? 1 coordination mode.

Sarma, Rupam; Baruah, Jubaraj B.

2011-09-01

394

Trinuclear complexes and coordination polymers of redox-active guanidino-functionalized aromatic (GFA) compounds with a triphenylene core.  

PubMed

Herein, we report on the synthesis, redox activity, and coordination chemistry of 2,3,6,7,10,11-hexakis(tetramethylguanidino)triphenylene. CV measurements indicated that the new compound could be oxidized in three separate reversible two-electron oxidation events. The HOMO and LUMO energies were estimated from the oxidation wave and the onset of absorption in the UV/vis spectrum. Our discussion also includes the related new compound 2,3,6,7,10,11-hexakis(N,N'-dimethylethyleneguanidino)triphenylene. Then trinuclear Cu(I) and Cu(II) complexes of the new triphenylene ligands were characterized, and their electronic properties are discussed. In contrast to previously studied redox-active GFA ligands, oxidation of trinuclear copper(I) iodide complexes with I2 leads to copper instead of ligand oxidation. In the tetra-coordinated Cu(II) complexes, the coordination mode is intermediate between tetrahedral and square planar. The optical properties of the complexes were studied, and low-energy electronic transitions were assigned to ligand-to-metal charge-transfer (LMCT) excitations. We then extended our analysis to trinuclear Ni(II) and Co(II) complexes. The magnetic coupling mediated through the triphenylene ligand in the trinuclear Cu(II) and Co(II) complexes was studied by SQUID magnetometry, revealing ferromagnetic coupling of the spin centers and different degrees of spin delocalization into the guanidino groups. Finally, we show that the GFA ligands could be linked to one- or two-dimensional coordination polymers and porous materials with a layer structure by reaction with silver halides. PMID:25188743

Lebkücher, Anna; Wagner, Christoph; Hübner, Olaf; Kaifer, Elisabeth; Himmel, Hans-Jörg

2014-09-15

395

Self-assembly of colloidal one-dimensional nanocrystals.  

PubMed

The ability of nanoscopic materials to self-organize into large-scale assembly structures that exhibit unique collective properties has opened up new and exciting opportunities in the field of nanotechnology. Although earlier work on nanoscale self-assembly has focused on colloidal spherical nanocrystals as building blocks, there has been significant interest in recent years in the self-assembly of colloidal nanocrystals having well-defined facets or anisotropic shapes. In this review, particular attention is drawn to anisotropic one-dimensional (1D) nanocrystals, notably nanorods and nanowires, which can be arranged into a multitude of higher-order assembly structures. Different strategies have been developed to realize self-assembly of colloidal 1D nanocrystals and these are highlighted in the first part of this review. Self-assembly can take place (1) on substrates through evaporation control, external field facilitation and template use; (2) at interfaces, such as the liquid-liquid and the gas-liquid interface; and (3) in solutions via chemical bonding, depletion attraction forces and linker-mediated interactions. The choice of a self-assembly approach is pivotal to achieving the desired assembly configuration with properties that can be exploited for functional device applications. In the subsequent sections, the various assembly structures that have been created through 1D nanocrystal self-assembly are presented. These organized structures are broadly categorized into non-close-packed and close-packed configurations, and are further classified based on the different types of 1D nanocrystal alignment (side-by-side and end-to-end), orientation (horizontal and vertical) and ordering (nematic and smectic), and depending on the dimensionality of the structure (2D and 3D). The conditions under which different types of arrangements are achieved are also discussed. PMID:24413386

Zhang, Shuang-Yuan; Regulacio, Michelle D; Han, Ming-Yong

2014-04-01

396

Density probability distribution in one-dimensional polytropic gas dynamics  

NASA Astrophysics Data System (ADS)

We discuss the generation and statistics of the density fluctuations in highly compressible polytropic turbulence, based on a simple model and one-dimensional numerical simulations. Observing that density structures tend to form in a hierarchical manner, we assume that density fluctuations follow a random multiplicative process. When the polytropic exponent ? is equal to unity, the local Mach number is independent of the density, and our assumption leads us to expect that the probability density function (PDF) of the density field is a log-normal. This isothermal case is found to be special, with a dispersion ?2s scaling as the square turbulent Mach number M~2, where s? ln ? and ? is the fluid density. Density fluctuations are stronger than expected on the sole basis of shock jumps. Extrapolating the model to the case ??1, we find that as the Mach number becomes large, the density PDF is expected to asymptotically approach a power-law regime at high densities when ?<1, and at low densities when ?>1. This effect can be traced back to the fact that the pressure term in the momentum equation varies exponentially with s, thus opposing the growth of fluctuations on one side of the PDF, while being negligible on the other side. This also causes the dispersion ?2s to grow more slowly than M~2 when ??1. In view of these results, we suggest that Burgers flow is a singular case not approached by the high-M~ limit, with a PDF that develops power laws on both sides.

Passot, Thierry; Vázquez-Semadeni, Enrique

1998-10-01

397

One-dimensional overdriven detonations with branched-chain kinetics  

NASA Astrophysics Data System (ADS)

The dynamics of time-dependent, planar propagation of gaseous detonations is addressed on the basis of a three-step chemistry model that describes branched-chain processes. Relevant nondimensional parameters are the ratio of the heat release to the thermal enthalpy at the Neumann state, the nondimensional activation energies for the initiation and branching steps, the ratio of the branching time to the initiation time and the ratio of the branching time to the recombination time. The limit of strong overdrive is considered, in which pressure remains constant downstream from the leading shock in the first approximation, and the ratio of specific heats ? is taken to be near unity. A two-term expansion in the strong overdrive factor is introduced, and an integral equation is derived describing the nonlinear dynamics and exhibiting a bifurcation parameter, the reciprocal of the product of (?-1), the nondimensional heat release and the nondimensional branching activation energy, with an acoustic correction. A stability analysis shows that, depending on values of the parameters, either the mode of lowest frequency or a mode of higher frequency may be most unstable. Numerical integrations exhibit different conditions under which oscillations die, low-frequency oscillations prevail, high-frequency oscillations prevail, highly nonlinear oscillations persist, or detonation failure occurs. This type of parametric analysis is feasible because of the relative simplicity of the model, which still is more realistic than a one-step, Arrhenius chemical approximation. In particular, by addressing the limit of slow radical recombination compared with branching, explicit results are derived for the critical value of the bifurcation parameter, involving the ratio of the recombination time to the induction time. The results help to clarify the general nature of one-dimensional detonation instability and provide simplifications that can be employed in efficiently relating gaseous detonation behavior to the true underlying chemistry.

Sánchez, Antonio L.; Carretero, Manuel; Clavin, Paul; Williams, Forman A.

2001-03-01

398

Two dimensionality in quasi-one-dimensional cobalt oxides  

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

399

One-dimensional itinerant interacting non-Abelian anyons  

NASA Astrophysics Data System (ADS)

We construct models of interacting itinerant non-Abelian anyons moving along one-dimensional chains. We focus on itinerant Ising (Majorana) and Fibonacci anyons, which are, respectively, related to SU(2)2 and SU(2)3 anyons and also, respectively, describe quasiparticles of the Moore-Read and Z3-Read-Rezayi fractional quantum Hall states. Following the derivation of the electronic large-U effective Hubbard model, we derive effective anyonic t-J models for the low-energy sectors. Solving these models by exact diagonalization, we find a fractionalization of the anyons into charge and (neutral) anyonic degrees of freedom—a generalization of spin-charge separation of electrons which occurs in Luttinger liquids. A detailed description of the excitation spectrum can be performed by combining spectra for charge and anyonic sectors. The anyonic sector is that of a squeezed chain of localized interacting anyons and, hence, is described by the same conformal field theory (CFT), with central charge c=1/2 for Ising anyons and c=7/10 or c=4/5 for Fibonacci anyons with antiferromagnetic or ferromagnetic coupling, respectively. The charge sector is the spectrum of a chain of hard-core bosons subject to phase shifts which coincide with the momenta of the combined anyonic eigenstates, revealing a subtle coupling between charge and anyonic excitations at the microscopic level (which we also find to be present in Luttinger liquids), despite the macroscopic fractionalization. The combined central charge extracted from the entanglement entropy between segments of the chain is shown to be 1+c, where c is the central charge of the underlying CFT of the localized anyon (squeezed) chain.

Poilblanc, Didier; Feiguin, Adrian; Troyer, Matthias; Ardonne, Eddy; Bonderson, Parsa

2013-02-01

400

One-dimensional quantum waveguide theory of Rashba electrons  

NASA Astrophysics Data System (ADS)

The ballistic spin transport in one-dimensional waveguides with the Rashba effect is studied. Due to the Rashba effect, there are two electron states with different wave vectors for the same energy. The wave functions of two Rashba electron states are derived, and it is found that their phase depend on the direction of the circuit and the spin directions of two states are perpendicular to the circuit, with the +?/2 and -?/2 angles, respectively. The boundary conditions of the wave functions and their derivatives at the intersection of circuits are given, which can be used to investigate the waveguide transport properties of Rashba spin electron in circuits of any shape and structure. The eigenstates of the closed circular and square loops are studied by using the transfer matrix method. The transfer matrix M(E ) of a circular arc is obtained by dividing the circular arc into N segments and multiplying the transfer matrix of each straight segment. The energies of eigenstates in the closed loop are obtained by solving the equation det[M(E )-I]=0. For the circular ring, the eigenenergies obtained with this method are in agreement with those obtained by solving the Schrödinger equation. For the square loop, the analytic formula of the eigenenergies is obtained first. The transport properties of the AB ring and AB square loop and double square loop are studied using the boundary conditions and the transfer matrix method. In the case of no magnetic field, the zero points of the reflection coefficients are just the energies of eigenstates in closed loops. In the case of magnetic field, the transmission and reflection coefficients all oscillate with the magnetic field; the oscillating period is ?m=hc/e, independent of the shape of the loop, and ?m is the magnetic flux through the loop. For the double loop the oscillating period is ?m=hc/2e, in agreement with the experimental result. At last, we compared our method with Koga's experiment.

Liu, Duan-Yang; Xia, Jian-Bai; Chang, Yia-Chung

2009-11-01

401

Initiation of propagation in a one-dimensional excitable medium  

NASA Astrophysics Data System (ADS)

This study examines the initiation of propagation in a one-dimensional fiber by local stimulation with a small electrode. The membrane dynamics is based on the generic FitzHugh-Nagumo model, reduced in a singular limit to a nonlinear heat equation. A steady-state solution of this nonlinear heat equation defines the critical nucleus, a time-independent distribution of potential that acts as a threshold for propagating wavefronts. The criterion for initiation of propagation from the initial conditions on potential is obtained by re-writing the nonlinear heat equation as a gradient flow of an energy and projecting this gradient flow onto an approximate solution space. Assuming that the evolving potential has a shape of a Gaussian pulse, the solution space consists of the amplitude of the pulse, a, and the inverse of its width, k. The evolution of the potential is visualized on the ( a, k) phase plane in which the rest state is a stable node and the critical nucleus solution is a saddle point. The criterion for initiating propagation takes the form of a pair of separatrices that bisect all possible pulse widths. For a specific pulse width, the separatrices determine the minimum amplitude necessary to start propagation. Infinitely broad pulses (space-clamped fiber) require amplitude equal to the membrane excitation threshold. As the width of the pulse decreases, the requirement on the amplitude grows. In a limit of very narrow pulses, the pulse width and the amplitude are related by a linear relationship corresponding to a constant charge delivered by the pulse.

Neu, John C.; Preissig, R. Stephen; Krassowska, Wanda

1997-02-01

402

A Linear Piperazine-Containing Ligand and Its Hg Coordination Polymer  

Microsoft Academic Search

Reactions of piperazine hexahydrate with triazol and paraformaldehyde afford a new piperazine-containing ligand: (N,N?-bis(1-H-1,2,4-triazole-1-yl)piperazine) (btp). X-ray crystal diffraction reveals that btp is an overall linear structure. Its Hg polymer displays a zigzag chain in which piperazine is held in the chair conformation. In addition, the spectra properties of the btp and 1 are investigated, the strong luminescence characteristics of btp

Wen-Juan Chu; Rui-Jun Li; Yao-Ting Fan; Hong-Wei Hou

2012-01-01

403

CuII coordination polymers based on 5-methoxyisophthalate and flexible N-donor ligands: Structures and magnetic properties  

NASA Astrophysics Data System (ADS)

Three CuII coordination polymers, {[Cu2(CH3O-ip)2(bmib)]}n (1), {[Cu2(CH3O-ip)2(bmib)2]}n (2) and {[Cu(CH3O-ip)(bbip)]•2H2O}n (3) (CH3O-H2ip is 5-methoxyisophthalic acid, bmib is 1,4-bis(2-methylimidazol-1-yl)butane and bbip is 1,3-bis(1H-benzimidazolyl)propane), have been synthesized by hydrothermal methods. Complexes 1-3 were structurally characterized by elemental analysis, infrared (IR) spectra and X-ray single-crystal diffraction. Complex 1 shows a 3D six-connected self-penetrating network based on paddlewheel secondary building units. Complex 2 has a 3-fold interpenetrating 3D diamond framework. Complex 3 possesses a 1D tube-like chain. Thermo-gravimetric and magnetic properties of 1-3 were also investigated.

Chang, Xin-Hong; Qin, Jian-Hua; Ma, Lu-Fang; Wang, Li-Ya

2014-04-01

404

Hydrothermal Synthesis of Two Ni(II) MetalOrganic Coordination Polymers Constructed from Dicarboxylate and Nitrogen-contained Ligands  

Microsoft Academic Search

Two new coordination polymers[Ni(2,4?-oba)(1,10-phen)]n (1) and {[Ni(2,4?-Hoba)2 (4,4?- bipy)(H2O)2]·2H2O}n (2) have been synthesized [2,4?-H2oba = 2-(4-carboxyphenoxy)benzoic acid, 1,10- phen = 1,10-phenanthroline and 4,4?-bipy = 4,4?-bipyridine]. The framework structures of these polymeric complexes have been determined by single-crystal X-ray diffraction studies. Complex 1 exhibits double-helical chains formed by ?-? stacking interactions from the phenyl rings of the 1,10-phen ligands. Complex 2

Feng Guo; Jian-Jun Li; Xian-Jiang Li; Bao-Yong Zhu; Xiu-Ling Zhang

2012-01-01

405

Simulation of mesogenic diruthenium tetracarboxylates: Development of a force field for coordination polymers of the MMX type.  

PubMed

A classical molecular mechanics force field, able to simulate coordination polymers (CP) based on ruthenium carboxylates (Ru2 (O2CReq )4 Lax) (eq = equatorial group containing aliphatic chains, Lax = axial ligand), has been developed. New parameters extracted from experimental data and quantum calculations on short aliphatic chains model systems were included in the generalized AMBER force field. The proposed parametrization was evaluated using model systems with known structure, containing either short or long aliphatic chains; experimental results were reproduced satisfactorily. This modified force field, although in a preliminary stage, could then be applied to long chain liquid crystalline compounds. The resulting atomistic simulations allowed assessing the relative influence of the factors determining the CP conformation, determinant for the physical properties of these materials. PMID:23436725

Castro, Maria Ana; Roitberg, Adrian E; Cukiernik, Fabio D

2013-06-01

406

Fano profiles in transmission spectra of terahertz radiation through one-dimensional periodic metallic structures  

E-print Network

Fano profiles in transmission spectra of terahertz radiation through one-dimensional periodic December 2010 The transmission properties of broadband terahertz radiation through one-dimensional periodic for the transmission of broadband terahertz radiation through one-dimensional periodic structures of metallic cylinders

407

Six new coordination polymers constructed by 3-carboxyl-5-oxycarboxymethylpyridinio-1-carboxylate: Crystal structures, topologies, photoluminescent and magnetic properties  

SciTech Connect

Six new two-dimensional (2D) coordination polymers, [ML(H{sub 2}O){sub 3}]{sub n} (M=Zn (1), Cd (2), Mn (3), Co (4)), [CdL(H{sub 2}O)]{sub n} (5), [CdL(4,4?-bipy)]{sub n}·nH{sub 2}O (6), (H{sub 2}L=3-carboxyl-5-oxycarboxymethylpyridinio-1-carboxylate, 4,4?-bipy=4,4?-bipyridine), have been hydrothermally synthesized and characterized by single crystal X-ray diffraction analyses, IR spectra, and thermogravimetric analyses. 1, 2, 3, 4 are isostructural and feature a binodal (4,6)-connected topology with left- and right-handed helical chains with a pitch of 9.9560 Å. 5 can be topologically presented as an uninodal 6-connected network if the hydrogen bonds are also considered. 6 is a binodal (3,5)-connected 2D layer network. The photoluminescent properties of 1, 2, 5, 6 and magnetic properties of 3, 4 have been studied and discussed. - Graphical abstract: The structural differences show that the ligand, the metal center, and the reaction conditions have great influence on the structure of the final assembly. - Highlights: • A new asymmetric flexible tricarboxylate ligand of 3-carboxyl-5-oxycarboxymethylpyridinio-1-carboxylate was synthesized. • Six new two-dimensional (2D) coordination polymers have been hydrothermally obtained. • 1, 2, 3, 4 are isostructural and feature a binodal (4,6)-connected topology with left- and right-handed helical chains. • The photoluminescent properties of 1, 2, 5, 6 and magnetic properties of 3, 4 have been studied.

Yuan, Hong-Yan [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Dazhou Vocational and Technical College, 448 Xujiabei Road, Sishuan 635000 (China); Han, Min-Min; Jiang, Xian-Rong; Jiang, Zhan-Guo [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Feng, Yun-Long, E-mail: sky37@zjnu.cn [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

2013-06-15

408

Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties  

NASA Astrophysics Data System (ADS)

A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln2(Hdpp)2(dpp)2]nLn=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H2dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1-5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln2(Hdpp)2]4+ basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions.

Feng, Xun; Liu, Lang; Wang, Li-Ya; Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong; Ng, Seik-Weng

2013-10-01

409

Strong correlations and topological order in one-dimensional systems  

NASA Astrophysics Data System (ADS)

This thesis presents theoretical studies of strongly correlated systems as well as topologically ordered systems in 1D. Non-Fermi liquid behavior characteristic of interacting 1D electron systems is investigated with an emphasis on experimentally relevant setups and observables. The existence of end Majorana fermions in a 1D p-wave superconductor subject to periodic, incommensurate and disordered potentials is studied. The Tomonaga-Luttinger liquid (TLL), a model of interacting electrons in one spatial dimension, is considered in the context of two systems of experimental interest. First, a study of the electronic properties of single-walled armchair carbon nanotubes in the presence of transverse electric and magnetic fields is presented. As a result of their effect on the band structure and electron wave functions, fields alter the nature of the (effective) Coulomb interaction in tubes. In particular, it is found that fields couple to nanotube bands (or valleys), a quantum degree of freedom inherited from the underlying graphene lattice. As revealed by a detailed TLL calculation, it is predicted that fields induce electrons to disperse into their spin, band, and charge components. Fields also provide a means of tuning the shell-filling behavior associated with short tubes. The phenomenon of charge fractionalization is investigated in a one-dimensional ring. TLL theory predicts that momentum-resolved electrons injected into the ring will fractionalize into clockwise- and counterclockwise-moving quasiparticles. As a complement to transport measurements in quantum wires connected to leads, non-invasive measures involving the magnetic field profiles around the ring are proposed. Topological aspects of 1D p-wave superconductors are explored. The intimate connection between non-trivial topology (fermions) and spontaneous symmetry breaking (spins) in one-dimension is investigated. Building on this connection, a spin ladder system endowed with vortex degrees of freedom is proposed in order to study the effects that inhomogeneous potentials have on the topological phase diagram. Periodic vortex patterns yield a rich parameter space for tuning into a topologically non-trivial phase. This analysis hinges on the development of a topological invariant based on the wave function of Majorana fermions which inhabit the ends of the system and are robust to disorder. The method is generalized to aperiodic and disordered potentials. The topological phase diagram of such systems is studied; numerical and analytic results are found to be in close agreement.

De Gottardi, Wade Wells

410

Organized one dimensional nanomaterials: From preparations to applications  

NASA Astrophysics Data System (ADS)

This thesis is mainly concerned with the development of organized one dimensional (1D) nanomaterials and their applications. We have synthesized Ag2S, Cu2S nanowires, Fe2O3 nanobelt and nanowire arrays and ZnO nanobelt arrays from corresponding metal substrate respectively via gas solid reaction methods under different growth conditions. The effect of various parameters including temperature, reaction time, composition of gas, surface pre-oxidation, size of source materials etc. on the growth of metal oxide/sulfide 1D nanostructure have been studied systemically. The size and morphology of these 1D nanomaterials could be rationally controlled by adjusting the growth conditions. A tip growth mechanism has been confirmed based our results. The properties including PL, Raman, field effect transistors, and field emission of these materials have been measured. Cu(OH)2 nanoribbons have been synthesized by a solution solid reaction method using Cu and Cu2S nanowires as precursors. Cu(OH) 2 nanoribbons can form well-aligned arrays on Cu substrate. Low temperature facilitate the formation of Cu(OH)2 nanoribbon arrays. Reaction conditions affect the morphology, crystal structure, even composition of the products much. CuO nanorod arrays of several nm in diameter could be synthesis in changed condition. Cu(OH)2 nanoribbon arrays are good sacrifice template for synthesizing other Cu-based 1D nanomaterials. It has been converted to CuO, Cu2O, Cu8S9, Cu etc. 1D nanostructure through different physical and chemical reaction process. Au/Cu2S core/sheath nanowires have been synthesized in solution phase via a simple template-induced redox deposition process, after removing the Cu2S template, Au nanotubes have been formed. The photoelectrochemistry (PEC) properties of it have been studied. Ag dendritic nanostructures have been prepared via solution reaction. We have revealed that the stem, branch, and sub-branch grow along <100>, <111> and <100> directions, respectively. Such a preferential growth pattern along <100> and <111> alternately lead to the formation of the Ag nanodendrites. In another development, we have synthesized unltrathin Zn nanowires (<5nm) by a vapor transport method. Small molecules are induced into the gas phase as capping reagents. In this process, the small molecules serve as capping reagents or templates to confine the lateral growth and facilitate the formation of ultrathin 1D nanostructures. (Abstract shortened by UMI.)

Wen, Xiaogang

411

Quasi-One-Dimensional Modeling of Pulse Detonation Rocket Engines  

NASA Technical Reports Server (NTRS)

Pulsed detonation rocket engines (PDREs) have generated considerable research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional rocket engines. The detonative mode of combustion employed by these devices offers a thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional rocket engines and gas turbines. However, while this theoretical advantage has spurred a great deal of interest in building PDRE devices, the unsteady blowdown process intrinsic to the PDRE has made realistic estimates of the actual propulsive performance problematic. The recent review article by Kailasanath highlights some of the difficulties in comparing the available experimental measurements with numerical models. In a previous paper by the author, parametric studies of the performance of a single, straight-tube PDRE were reported. A 1-D, unsteady method of characteristics code, employing a constant-gamma assumption behind the detonation front, was developed for that study. Models of this type are computationally inexpensive, and are particularly useful for parametric performance comparisons. For example, a plot showing the specific impulse of various PDRE and steady-state rocket engine (SSRE) configurations as a function of blowdown pressure ratio. The performance curves clearly indicate that a straight-tube PDRE is superior in specific impulse to a SSRE with a sonic nozzle over the entire range of pressure ratios. Note, however, that a straight-tube PDRE in general does not compare favorably to a SSRE fitted with an optimized de Laval supersonic nozzle, particularly at the high pressure ratios typical for boost or in-space rocket applications. However, the calculations also show that if a dynamically optimized, supersonic de Laval nozzle could be could be fitted to a PDRE, then the specific impulse of the device would exceed that of a comparable SSRE. While such a nozzle is a considerable idealization, it is clear that nozzle design and optimization will play a critical role in whether the performance potential of PDREs can be effectively realized in practice. In order to study PDRE nozzle issues with greater accuracy, a quasi-one-dimensional, finite-rate chemistry CFD code has been developed by the author. Comparisons of the code with both the previous MOC model and experimental data from Stanford University are reported. The effect of constant-gamma and finite-rate chemistry assumptions on the flowfield and performance is examined. Parametric studies of the effect of nozzle throat size and expansion ratio, at various blowdown pressure ratios, are reported.

Morris, Christopher I.

2002-01-01

412

Bioinspired one-dimensional materials for directional liquid transport.  

PubMed

One-dimensional materials (1D) capable of transporting liquid droplets directionally, such as spider silks and cactus spines, have recently been gathering scientists' attention due to their potential applications in microfluidics, textile dyeing, filtration, and smog removal. This remarkable property comes from the arrangement of the micro- and nanostructures on these organisms' surfaces, which have inspired chemists to develop methods to prepare surfaces with similar directional liquid transport ability. In this Account, we report our recent progress in understanding how this directional transport works, as well our advances in the design and fabrication of bioinspired 1D materials capable of transporting liquid droplets directionally. To begin, we first discuss some basic theories on droplet directional movement. Then, we discuss the mechanism of directional transport of water droplets on natural spider silks. Upon contact with water droplets, the spider silk undergoes what is known as a wet-rebuilt, which forms periodic spindle-knots and joints. We found that the resulting gradient of Laplace pressure and surface free energy between the spindle-knots and joints account for the cooperative driving forces to transport water droplets directionally. Next, we discuss the directional transport of water droplets on desert cactus. The integration of multilevel structures of the cactus and the resulting integration of multiple functions together allow the cactus spine to transport water droplets continuously from tip to base. Based on our studies of natural spider silks and cactus spines, we have prepared a series of artificial spider silks (A-SSs) and artificial cactus spines (A-CSs) with various methods. By changing the surface roughness and chemical compositions of the artificial spider silks' spindle-knots, or by introducing stimulus-responsive molecules, such as thermal-responsive and photoresponsive molecules, onto the spindle-knots, we can reversibly manipulate the direction of water droplet's movement on the prepared A-SSs. In addition, the A-SSs with nonuniform spindle-knots, such as multilevel sized spindle-knots and gradient spindle-knots, further demonstrate integrated directional transport ability for water droplets. Through mimicking the main principle of cactus spines in transporting water droplets, we were able to fabricate both single and array A-CSs, which are able to transport liquid droplets directionally both in air and under water. Lastly, we demonstrated some applications of this directional liquid transport, from aspects of efficient fog collection to oil/water separation. In addition, we showed some potential applications in smart catalysis, tracer substance enrichment, smog removal, and drug delivery. PMID:25019657

Ju, Jie; Zheng, Yongmei; Jiang, Lei

2014-08-19

413

New Inorganic/Organic Coordination Polymers Generated from Bidentate Schiff-Base Yu-Bin Dong, Mark D. Smith, and Hans-Conrad zur Loye*  

E-print Network

in the solid state. Introduction Owing to their potential as new functional solid materials,1-4 interest. Four new coordination polymers are prepared by solution reactions and fully characterized by infrared, the inorganic counterions, and the metal-to- ligand ratio.9-12 So far, among the many diverse efforts to find

zur Loye, Hans-Conrad

414

Eutectic mixture of choline chloride\\/urea as a green solvent in synthesis of a coordination polymer: [Zn(O 3PCH 2CO 2)] · NH 4  

Microsoft Academic Search

A eutectic mixture of choline chloride\\/urea is liquid at ambient temperature and is used as a non-volatile reaction medium for the synthesis and crystallization of a novel coordination polymer, Zn(O3PCH2CO2)·NH4, in which structure-directing ammonium ions are generated in situ from the partial decomposition of urea.

Ju-Hsiou Liao; Pei-Chi Wu; Yi-Hsuan Bai

2005-01-01

415

Lamb wave band gaps in one-dimensional radial phononic crystal slabs  

NASA Astrophysics Data System (ADS)

In this paper, we theoretically investigate the band structures of Lamb wave in one-dimensional radial phononic crystal (PC) slabs composed of a series of alternating strips of epoxy and aluminum. The dispersion relations, the power transmission spectra and the displacement fields of the eigenmodes are calculated by using the finite element method based on two-dimensional axial symmetry models in cylindrical coordinates. The axial symmetry model is validated by three-dimensional finite element model in Cartesian coordinates. Numerical results show that the proposed radial PC slabs can yield several complete band gaps with a variable bandwidth exist for elastic waves. Furthermore, the effects of the filling fraction and the slab thickness on the band gaps are further explored numerically. It is worth observing that, with the increase of the filling fraction, both the lower and upper edges of the band gaps are simultaneously shifted to higher frequency, which results from the enhancement interaction between the rigid resonance of the scatterer and the matrix. The slab thickness is the key parameter for the existence and the width of complete band gaps in the radial PC slabs. These properties of Lamb waves in the radial PC plates can potentially be applied to optimize band gaps, generate filters and design acoustic devices in the rotary machines and structures.

Li, Yinggang; Chen, Tianning; Wang, Xiaopeng

2015-10-01

416

Structure modulation of manganese coordination polymers consisting of 1,4-naphthalene dicarboxylate and 1,10-phenanthroline.  

PubMed

Three new manganese coordination polymers, {[Mn2(1,4-NDC)2(phen)2](H2O)}n (1), [Mn2(1,4-NDC)2(phen)(H2O)]n (2) and {[Mn4(1,4-NDC)4(phen)4](DMF)2}n (3) (1,4-H2NDC = 1,4-naphthalene dicarboxylic acid; phen = 1,10-phenanthroline; DMF = N,N-dimethylformamide), have been synthesized solvo/hydrothermally. 1,4-NDC(2-) ligands adopt different coordination modes under different solvents and concentrations which promotes different crystal structure formation. X-ray crystal structural data reveal that compounds 1, 2 and 3 crystallize in monoclinic space groups C2/c, P21/c and C2/c, respectively. Compound 1 has Mn2 dimers connected by 1,4-NDC(2-) linkers, packing into a 2D structure in a grid pattern. Compound 2 has a three-dimensional (3D) structure which is constructed by Mn2 dimers and 1,4-NDC(2-) linkers. Each MnO4N2 node of compound 3 is linked to another by 1,4-NDC(2-) ligands to form a two-dimensional (2D) structure. Variable-temperature magnetic susceptibilities of compounds 1-3 exhibit overall weak antiferromagnetic coupling between the adjacent Mn(II) ions. PMID:24756312

Lou, Yongbing; Wang, Jingjing; Tao, Yinhua; Chen, Jinxi; Mishima, Akio; Ohba, Masaaki

2014-06-14

417

Synthesis of microcrystals of the [Fe(L)(bipy)] spin crossover coordination polymer in a poly-4-vinylpyridine matrix.  

PubMed

Microcrystals of the spin-crossover coordination polymer [FeL(bipy)] (L=[3,3']-[1,2-phenylenebis(iminoethylidyne)]bis-(2,4-pentanedionato)(2-), bipy=4,4'-bipyridine) have been prepared in a poly(4-vinylpyridine) (P4VP) matrix. This was done by sequential addition of the iron(II) precursor complex and the bridging ligand bipy to a P4VP matrix, and by repetition of this cycle. The obtained composite material was characterized using TEM, SEM, XRPD, and SQUID measurements, and Mössbauer spectroscopy. With repeating cycles, the size of the [FeL(bipy)] crystals in the P4VP matrix increases from submicrometer to micrometer dimensions. A strong dependence on the number of cycles is observed. Above a critical size and concentration, the microcrystals show the same cooperative spin transition as the bulk material. No indication for a gradual spin transition is observed, but the remaining iron centers are either high-spin or low-spin depending on the coordination environment. PMID:24938532

Göbel, Christoph; Palamarciuc, Tatiana; Lochenie, Charles; Weber, Birgit

2014-08-01

418

Csbnd H⋯Pd interactions: One dimensional heteropolynuclear complexes  

NASA Astrophysics Data System (ADS)

Three cyanide complexes, [Cu(hepH)2Pd(?-CN)2(CN)2]n (1), [Zn(hepH)2Pd(?-CN)2(CN)2]n (2) and [Cd(hepH)2Pd(?-CN)2(CN)2]n (3) (2-pyridineethanol abbreviated to hepH), have been synthesized and characterized by various techniques (elemental analysis, FT-IR and Raman spectroscopy, thermal analysis and single crystal X-ray diffraction). FT-IR spectroscopy pointed out the existence of terminal and bridged cyanide ligands in the complexes. The crystallographic analyses reveal that complexes 1 and 2 crystallize in the triclinic system, space group P - 1 and complex 3 crystallizes in the monoclinic system, space group P21/n. The palladium atom is coordinated with cyanide-carbon atoms in a square-planar arrangement and the metal(II) atoms are six-coordinated with two cyanide nitrogen, two hepH nitrogen and two hepH oxygen atoms, in a distorted octahedral arrangement. In all the complexes adjacent chains are connected by Csbnd H⋯Pd, ?⋯? and Osbnd H⋯N hydrogen bonding interactions to form two- and three-dimensional networks. When it comes to thermal analysis, the complexes followed usual decomposition mechanism in which neutral ligands (hepH) are released first, and then cyanide ligands are decomposed. The final decomposition products are found to be the corresponding metal oxides.

Say?n, Elvan; Kürkçüo?lu, Güne? Süheyla; Ye?ilel, Okan Zafer; Hökelek, Tuncer

2014-11-01

419

Applications of One-Dimensional Nanomaterials for Stretchable Electronics  

NASA Astrophysics Data System (ADS)

Electronics that can be stretched and/or conformal to curvilinear surfaces has recently attracted broad attention. Success of stretchable electronics depends on the availability of electronic materials and structures that can be highly stretched, compressed, bent, and twisted. One-dimensional (1D) nanomaterials are expected to aid the development of the stretchable electronic systems by improving performance, expanding integration possibilities, and potentially lowering cost, due to their superior mechanical/electronic/optical properties, high aspect ratios, and compatibility with bulk synthesis. This dissertation is primarily focused on the application of 1D nanomaterials, including silicon nanowires (SiNWs), carbon nanotubes (CNTs) and silver nanowires (AgNWs) for stretchable electronics. The mechanical properties of SiNWs, grown by the vapor-liquid-solid process, were first studied with in situ tensile tests inside a scanning electron microscope (SEM). It was found that the fracture strain increased from 2.7% to about 12% when the NW diameter decreased from 60 to 15 nm. The Young's modulus decreased while the fracture strength increased up to 12.2 GPa, as the nanowire diameter decreased. The fracture strength also increased with the decrease of the side surface area. Repeated loading and unloading during tensile tests demonstrated that the nanowires are linear elastic until fracture without appreciable plasticity. Then, SiNW coils were fabricated on elastomeric substrates by a controlled buckling process. SiNWs were first transferred onto prestrained and ultraviolet/ozone (UVO)-treated poly(dimethylsiloxane) (PDMS) substrates and buckled upon release of the prestrain. Two buckling modes (the in-plane wavy mode and the three-dimensional coiled mode) were found; a transition between them was achieved by controlling the UVO treatment of PDMS. Structural characterization revealed that the NW coils were oval-shaped. The oval-shaped NW coils exhibited very large stretchability up to the failure strain of PDMS (˜104% in our study). Such a large stretchability relies on the effectiveness of the coil shape in mitigating the maximum local strain, with a mechanics that is similar to the motion of a coil spring. Single NW devices based on coiled NWs were demonstrated with a nearly constant electrical response in a large strain range. In addition to the wavy shape, the coil shape represents an effective architecture in accommodating large tension, compression, bending, and twist, which may find important applications for stretchable electronics and other stretchable technologies. For CNTs, wavy CNT ribbons coated with a thin layer of Au/Pd film were fabricated on PDMS substrates through mechanical buckling. Covered with a top layer of PDMS, the wavy CNT ribbons are able to accommodate large stretching (up to 100%) with little change in resistance. Significantly, a new manufacturing strategy for buckling of aligned CNTs was developed, which does not involve prestretching the substrate but relies on the interface interaction between the CNTs and the substrate. More specifically, upon stretching the substrate the CNTs slide on the substrate, but upon releasing the CNTs buckle. Following this manufacturing strategy, stretchable conductors based on aligned CNTs were demonstrated. At last, a highly conductive and stretchable conductor with AgNWs embedded just below the surface of PDMS was fabricated. Stable conductivity of 5,285 S cm-1 was achieved in a large range of tensile strain (0-50%) after a few cycles of stretching/releasing of the substrate. This stable electric response is due to buckling of the AgNW/PDMS thin layer, which is attributed to irreversible sliding of the AgNWs in the PDMS matrix. AgNWs can be printed to fabricate patterned stretchable conductors with feature size as small as 50 microm. Furthermore, a stretchable light emitting diode (LED) circuit and a capacitive strain sensor were demonstrated using the AgNW-based stretchable conductors as interconnects or electrodes.

Xu, Feng

420

One-dimensional Bose gas on an atom chip  

NASA Astrophysics Data System (ADS)

We describe experiments investigating the (coherence) properties of a finite-temperature one-dimensional (1D) Bose gas with repulsive interactions. The confining magnetic field is generated with a micro-electronic circuit. This microtrap for atoms or `atom chip' is particularly suited to generate a tight waveguide for atoms close to the chip surface. In contrast to the usual case of Bose-Einstein condensation in 3D, in 1D the system is not characterized by long-range phase coherence. Further interest in the 1D Bose gas stems from the fact that it forms the textbook example for the many-body quantum-mechanical systems that can be exactly solved using the Bethe Ansatz. Moreover, using a method developed by Yang and Yang, exact expressions for the thermodynamics of this system can be given. We summarize the theoretical background that is relevant to describe the (nearly) 1D gas in our experiments. The design and construction of our microtrap is described in some detail. We discuss the technique of Bose-gas focusing, in particular how it applies to our 1D system, and demonstrate that it can be used to probe the momentum distribution of the 1D gas. Finally, we perform a direct comparison of the measured in situ density distribution to the predictions of a model based on the exact Yang-Yang thermodynamics and find very good agreement. Gaz de Bose unidimensionnel sur une puce atomique. Nous décrivons des expériences permettant d'étudier les propriétés (en particulier la cohérence) d'un gaz unidimensionel (1D) de Bose à température finie avec des interactions répulsives. Le champ magnétique confinant est créé par un circuit micro-électronique. Ce micro-piège à atomes ou "puce atomique" est particulièrement adapté pour générer un guide très confinant pour les atomes près de la surface de la puce. Contrairement au cas habituel de la condensation de Bose-Einstein en 3D, le système uni-dimensionnel n'est pas caractérisé par une cohérence de phase à longue portée. Un intérêt supplémentaire du gaz uni-dimensionnel de Bose est qu'il offre un cas d'école de systèmes quantiques à plusieurs corps pouvant être résolus exactement en utilisant l'ansatz de Bethe. De plus, grâce à une méthode développée par Yang et Yang, on peut obtenir les expressions exactes de la thermodynamique de ces systèmes. Nous rappelons le cadre théorique permettant de décrire le gaz quasi-unidimensionel dans nos expériences. La conception et la construction de notre micro-piège sont décrits en détails. Nous discutons la technique de focalisation du gaz de Bose, et en particulier son application à notre système unidimensionel, et nous montrons qu'elle peut être utilisée pour déterminer la distribution d'impulsions du gaz unidimensionel. Finalement, nous comparons directement la distribution de densité mesurée in situ, aux prédictions d'un modèle basé sur la thermodynamique exacte de Yang et Yang et nous trouvons un très bon accord.

van Amerongen, A. H.

421

A series of M-M' heterometallic coordination polymers: syntheses, structures and surface photoelectric properties (M=Ni/Co, M'=Cd/Zn)  

SciTech Connect

Four new heterometallic polymers, [NiCd(mal){sub 2}(H{sub 2}O){sub 2}]n.2nH{sub 2}O 1, [NiZn{sub 2}(Hcit){sub 2}(H{sub 2}O){sub 2}]n 2, [CoCd{sub 2}(Hcit){sub 2}(H{sub 2}O){sub 2}]n 3, [CoZn{sub 2}(Hcit){sub 2}(H{sub 2}O){sub 2}]n 4 (H{sub 2}mal=malonic acid, H{sub 4}cit=citric acid) were synthesized and characterized. The photoelectric properties of the polymers were discussed by the surface photovoltage spectroscopy (SPS). The structural analyses indicate 1 is a Ni-Cd heterometallic polymer with 3D structure bridged by the mal{sup 2-} group. 2-4 are all heterometallic polymers with 2D structures bridged by the Hcit{sup 3-} group. The results of SPS for the four polymers reveal that there are wide photovoltage response bands in the range of 300-800 nm, which indicates that they all possess photoelectric conversion properties. By the introduction of the other metals, the SPS of heterometallic polymers are broadened obviously than the SPS of monometallic complexes. Moreover, the relationships between SPS and UV-Vis absorption spectra have been discussed. -- Graphical Abstract: Four heterometallic polymers, Ni-Cd, Ni-Zn, Co-Cd, Co-Zn, were synthesized and characterized. The photoelectric properties of heterometallic polymers were discussed by SPS. The introduction of heterometallic ions will broaden the SPS of corresponded monometallic complexes. Display Omitted highlights: > Four new heterometallic coordination polymers were reported. > The surface photoelectric properties of heterometallic polymers were studied by SPS. > They all possess photoelectric conversion properties. > The SPS of heterometallic polymers are broadened than that of monometallic complexes.

Li, Lei [School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Niu, Shu-Yun, E-mail: syniu@sohu.co [School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Jin, Jing; Meng, Qin; Chi, Yu-Xian; Xing, Yong-Heng [School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Zhang, Guang-Ning [Institute of Chemistry for Functionalized Materials, Liaoning Normal University, Dalian 116029 (China)

2011-05-15

422

Computational screening of structural and compositional factors for electrically conductive coordination polymers.  

PubMed

The combination of organic and inorganic chemical building blocks to form metal-organic frameworks (MOFs) offers opportunities for producing functional materials suitable for energy generation, storage and conversion. However, such applications rely on robust electron transport and the design of conductive hybrid materials is still in its infancy. Here we apply density functional theory to assess the important structural and compositional factors for forming conducting MOFs. We focus on 1D metal-organic polymers as a model system and assess the choice of organic, inorganic and linking units. The results demonstrate that electronic communication is sensitive to the energy and symmetry of the frontier orbitals associated with the organic and inorganic building blocks and offers guidance on how to optimise electrical conduction in hybrid materials. PMID:24569694

Tiana, Davide; Hendon, Christopher H; Walsh, Aron; Vaid, Thomas P

2014-07-28

423

A novel two-dimensional Cd(II) coordination polymer: poly[aqua[??-2-(4-carboxylatobenzoyl)benzoato]cadmium(II)].  

PubMed

The title Cd(II) coordination framework, [Cd(C15H8O5)(H2O)]n or [Cd(bpdc)(H2O)]n [H2bpdc is 2-(4-carboxybenzoyl)benzoic acid], has been prepared and characterized using IR spectroscopy, elemental analysis, thermal analysis and single-crystal X-ray diffraction. Each Cd(II) centre is six-coordinated by two O atoms from one 2-(4-carboxylatobenzoyl)benzoate (bpdc(2-)) ligand in chelating mode, three O-donor atoms from three other bpdc(2-) anions and one O atom from a coordinated water molecule in an octahedral coordination environment. Two crystallographically equivalent Cd(II) cations are bridged by one O atom of the 2-carboxylate group of one bpdc(2-) ligand and by both O atoms of the 4-carboxylate group of a second bpdc(2-) ligand to form a binuclear [(Cd)2(O)(OCO)] secondary building unit. Adjacent secondary building units are interlinked to form a one-dimensional [Cd(OCO)2]n chain. The bpdc(2-) ligands link these rod-shaped chains to give rise to a complex two-dimensional [Cd(bpdc)]n framework with a 4,4-connected binodal net topology of point symbol {4(3).6(2).8}. The compound exhibits a strong fluorescence emission and typical ferroelectric behaviour in the solid state at room temperature. PMID:25370111

Chen, Hui-Ru; Zhang, Wen-Wen

2014-11-01

424

Three NEW butane-1,2,3,4-tetracarboxylato-bridged coordination polymers: Syntheses, crystal structures and charaterization  

NASA Astrophysics Data System (ADS)

Three new butane-1,2,3,4-tetracarboxylato bridged coordination polymers [Zn 2(H 2O) 4(BTC)]·3H 2O 1, [Cd 2(H 2O) 4(BTC)]·2H 2O 2 and [Y 2(H 2O) 6(H 2BTC)(BTC)]·5H 2O 3 (H 4BTC = butane-1,2,3,4-tetracarboxylic acid) were synthesized and characterized by IR spectroscopy, TG-DTA analyses, elemental analyses and single-crystal X-ray diffraction, and their fluorescence properties were also investigated. In 1, the trigonal pyramidally coordinated Zn atoms are brigded by both ? 6? 6 and ? 6? 8 centrosymmetric BTC 4- anions into 2D layers, which are connected by the octahedrally coordinated Zn atoms to build up 3D (4 4·6 10·8)(4 4·6 2) 2(4 4·6 8·8 2·10) topological framework with the lattice water molecules in cavities. In 2, the CdO 7 pentagonal bipyramids and the CdO 8 4,4'-bicapped triagonal antiprisms are edge-shared to generate the Cd 2O 13 bipolyhedra, which are further corner-shared into 1D metal-oxide chains. The resulting chains are interconnected by the ? 6? 8 BTC 4- anion to form 2D (4 3) 2(4 6·6 6·8 3) networks, which are assembled via interlayer hydrogen bonds into a 3D (4 11·6 11·8 6)(4 3)(4 9·6) topological supramolecular architecture with the lattice H 2O molecules located in holes. The distorted 4,4'-bicapped triagonal antiprismatically coordinated Y atoms in 3 are interconnected ? 4? 4 H 2BTC 2- and ?4? 6 BTC 4- anions to from 2D (4 4·6 2) topological networks, which are held together via strong interlayer hydrogen bonds into a 3D fsc topological supramolecular architecture with the lattice water molecules residing in cavities.

Zhu, Hong-Lin; Zheng, Yue-Qing

2010-04-01

425

Structural characterization, electrochemical, photoluminescence and thermal properties of potassium ion-mediated coordination polymer.  

PubMed

A polymeric potassium complex of p-nitrophenol was synthesized and characterized by analytical and spectroscopic techniques. Molecular structure of the complex was determined by single crystal X-ray diffraction study. X-ray structural data show that crystals contain polymeric K(+) complex of p-nitrophenol. Asymmetric unit consists of one p-nitrophenolate, one K(+) ion and one water molecule. All bond lengths and angles in the phenyl rings have normal Csp2-Csp2 values and are in the expected ranges. The p-nitrophenolate is close to planar with small distortions by some atoms. Each potassium ion in the polymeric structure is identical and eight-coordinate, bonded to four nitro, two phenolate oxygen atoms from five p-nitrophenolate ligands and two oxygen atoms from two water molecules. Electronic, electrochemical, photoluminescence and thermal properties of the complex were also investigated. PMID:25698438

Ceyhan, Gökhan; Köse, Muhammet; Tümer, Mehmet; Dal, Hakan

2015-05-01

426

Particle paths and phase plane for time-dependent similarity solutions of the one-dimensional Vlasov-Maxwell equations  

NASA Technical Reports Server (NTRS)

The phase trajectories of particles in a plasma described by the one-dimensional Vlasov-Maxwell equations are determined qualitatively, analyzing exact general similarity solutions for the cases of temporally damped and growing (sinusoidal or localized) electric fields. The results of numerical integration in both untransformed and Lie-group point-transformed coordinates are presented in extensive graphs and characterized in detail. The implications of the present analysis for the stability of BGK equilibria are explored, and the existence of nonlinear solutions arbitrarily close to and significantly different from the BGK solutions is demonstrated.

Roberts, Dana Aaron; Abraham-Shrauner, Barbara

1987-01-01

427

Model calculations on the band structures of one-dimensional mixed donor-acceptor systems  

NASA Astrophysics Data System (ADS)

The band structures of one-dimensional donor-acceptor (D-A) stacks have been studied by means of the crystal-orbital (CO) formalism based on the tight-binding approximation. The model polymers of the present study are composed of quinhydrone moieties (10 and 11) where the donor and acceptor groups show either a parallel or a perpendicular orientation. These idealized systems have been adopted as models for D-A polymers in the recently synthesized class of D-A phanes. The strength of the D-A interaction has been modified due to alterations of the D-A distances within the unit cells and due to modifications in the effective electronegativity of the active groups (hydroxyl and carbonyl). The computational framework is a semiempirical intermediate neglect of differential overlap (INDO) CO formalism with a variable model Hamiltonian that allowed the simulation of the different types of D-A interactions (weak versus strong D-A pairs). An insulator-metal transition is predicted in the 0° arrangement of 10 for short D-A distances and larger differences in the electronegativities of both fragments. The 90° conformation shows an avoided crossing between the highest filled and the lowest unfilled ?(k) curves. This leads to a finite band gap for all studied interaction conditions. The band structures, the charge transfer in the D-A stacks, and the excited-state properties of 10 and 11 are analyzed as a function of the D-A geometry (distance, mutual orientation) and as a function of the strength of the D-A pairs. Semiquantitative solid-state models are compared with the INDO CO data, synthetic strategies for the design of D-A phanes with small (vanishing) band gaps are formulated, and various solid-state effects encountered in related low-dimensional D-A systems are briefly discussed.

Böhm, Michael C.; Vogler, Helmut

1983-09-01

428

One-dimensional transient analysis of volumetric heating for laser drilling  

SciTech Connect

Generally laser energy is considered to interact only with the substrate surface, as in metals, where the laser beam does not propagate into the substrate beyond a very small absorption depth. There are, however, many instances, particularly for ceramics and polymers, where the laser beam can penetrate into the substrate to substantial depths depending on the laser wavelength and laser-material interaction characteristics. Specifically there are polymeric dielectrics used as multilayer electronic substrates in which a laser beam of wavelength 9.3 {mu}m can penetrate into the substrate. The laser energy interacts at the substrate surface as well as inside the substrate. This particular aspect of laser-material interactions is important in laser drilling of blind microvias in polymeric multilayer electronic substrates. A one-dimensional transient heat conduction model including vaporization parameters is constructed to analyze this behavior. The absorption coefficient of the dielectric is also considered in this model and the problem is solved analytically. The microvia drilling speed, temperature distribution in the dielectric, and the thickness of the residue along the microvia walls and at the bottom of the microvia are studied for different laser irradiation conditions. An overheated metastable state of material is found to exist inside the workpiece. The overheating parameters are calculated for various laser drilling parameters and are used to predict the onset of thermal damage and to minimize the residue.

Zhang Chong; Salama, Islam A.; Quick, Nathaniel R.; Kar, Aravinda [Department of Mechanical, Materials and Aerospace Engineering, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States); Intel Corporation-Assembly and Technology Development, 5000 W. Chandler Boulevard, CH5-159, Chandler, Arizona 85226-3699 (United States); AppliCote Associates, LLC, 1445 Dolgner Place, Suite 23, Sanford, Florida 32771 (United States); College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States)

2006-06-01

429

Mosaic-like micropillar array for hard x-ray focusing—one-dimensional version  

NASA Astrophysics Data System (ADS)

An array of microstructures resembling a Fresnel version of the classical parabolic x-ray refractive lens shape shows a significant improvement towards focal spot size and intensity. The proposed polymer microstructures with the acting refractive surface have a pillar-like form with a triangular cross-section. Their arrangement and the parameters of the triangles change along the lenses in accordance with the x-ray propagation law, yielding a focusing effect in the hard x-ray range. The great number of micropillars arranged in one row conduct the x-ray beam like a waveguide, with its transparency increasing with decreasing pillar size. A multi-row lens can collect x-rays into a focus down to several nanometres. The specific regular arrangement of the pillars resembles a mosaic ornament, which led to the chosen name. Fabricating the lenses by means of deep x-ray lithography is essential for avoiding various potential manufacturing difficulties. The one-dimensional focusing lenses overcome the diffraction limit defined for the classical parabolic lenses due to their large aperture that results from the waveguide-like rows formed by the pillar arrangement.

Nazmov, Vladimir; Mohr, Juergen; Simon, Rolf

2013-09-01

430

Uranyl sensitization of samarium(III) luminescence in a two-dimensional coordination polymer.  

PubMed

Heterometallic carboxyphosphonates UO(2)(2+)/Ln(3+) have been prepared from the hydrothermal reaction of uranyl nitrate, lanthanide nitrate (Ln = Sm, Tb, Er, Yb), and phosphonoacetic acid (H(3)PPA). Compound 1, (UO(2))(2)(PPA)(HPPA)(2)Sm(H(2)O)·2H(2)O (1) adopts a two-dimensional structure in which the UO(2)(2+) metal ions bind exclusively to the phosphonate moiety, whereas the Ln(3+) ions are coordinated by both phosphonate and carboxylate functionalities. Luminescence studies of 1 show very bright visible and near-IR samarium(III)-centered emission upon direct excitation of the uranyl moiety. The Sm(3+) emissive state exhibits a double-exponential decay with lifetimes of 67.2 ± 6.5 and 9.0 ± 1.3 ?s as measured at 594 nm, after excitation at both 365 and 420 nm. No emission is observed in the region typical of the uranyl cation, indicating that all energy is either transferred to the Sm(3+) center or lost to nonradiative processes. Herein we report the synthesis, crystal structure, and luminescent behavior of 1, as well as those of the isostructural terbium, erbium, and ytterbium analogues. PMID:22171660

Knope, Karah E; de Lill, Daniel T; Rowland, Clare E; Cantos, Paula M; de Bettencourt-Dias, Ana; Cahill, Christopher L

2012-01-01

431

C-H...Cl relevant discrepancy on structure, magnetic and electronic conductivity of two mixed-valence Cu{sup I}Cu{sup II} coordination polymers  

SciTech Connect

Two mixed-valence Cu{sup I}Cu{sup II} coordination polymers [Cu{sup I}Cu{sup II}(qdiol)ClL]{sub n} (qdiol{sup 2-}=2,3-dioxyquinoxalinate, L=2,2'-bipyridine, 1; L=1,10-phenanthroline, 2) were obtained in basic ethanolic solution of CuCl{sub 2}, 1,4-dihydro-2,3-quinoxalinedione and L under the solvothermal condition. 1 and 2 are similar in composition, but differ remarkably in structure. The coordination modes of Cu{sup II}, qdiol{sup 2-} and L are identical in both complexes. But the Cu{sup I} ions are two- and three-coordinated, and the Cl{sup -} ions are terminal and bridging, in 1 and 2, respectively, which are relevant to the significantly different C-H...Cl hydrogen bonding pattern of bpy and phen. The temperature variable magnetic susceptibilities show that 1 is paramagnetic and 2 is weakly antiferromagnetic. The complex impedance spectroscopic studies indicate that both 1 and 2 are semiconductors and 2 is more conducting. - Graphical Abstract: Subtly different C-H...Cl bonding nature leads to diverse coordination modes and supramolecular networks, as well as physical properties of two Cu{sup I}Cu{sup II} coordination polymers with similar compositions. Highlights: > Two new Cu(I)-Cu(II) mixed-valence coordination polymers are obtained. > Environments of Cu(I) and Cl are different caused by C-H...Cl H-bonding. > Supramolecular networks are hence diverse. > Magnetic and semiconducting properties are influenced by the structures.

Shi Ling [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Yang Ping [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510631 (China); Huang Guang; Li Qian [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang Ning [Research Institute of Tsinghua University in Shenzhen, Shenzhen 518055 (China); Wu Jianzhong, E-mail: wujzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Yu Ying [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

2011-07-15

432

Simulation of one-dimensional evolution of wind waves in a deep water  

NASA Astrophysics Data System (ADS)

A direct wave model based on the one-dimensional nonlinear equations for potential waves is used for simulation of wave field development under the action of energy input, dissipation, and nonlinear wave-wave interaction. The equations are written in conformal surface-fitted nonstationary coordinate system. New schemes for calculating the input and dissipation of wave energy are implemented. The wind input is calculated on the basis of the parameterization developed through the coupled modeling of waves and turbulent boundary layer. The wave dissipation algorithm, introduced to prevent wave breaking instability, is based on highly selective smoothing of the wave surface and surface potential. The integration is performed in Fourier domain with the number of modes M = 2048, broad enough to reproduce the energy downshifting. As the initial conditions, the wave field is assigned as train of Stokes waves with steepness ak = 0.15 at nondimensional wavenumber k = 512. Under the action of nonlinearity and energy input the spectrum starts to grow. This growth is followed by the downshifting. The total time of integration is equal to 7203 initial wave periods. During this time the energy increased by 1111 times. Peak of the spectrum gradually shifts from wavenumber nondimensional k = 512 down to k = 10. Significant wave height increases 33 times, while the peak period increases 51 times. Rates of the peak downshift and wave energy evolution are in good agreement with the JONSWAP formulation.

Chalikov, Dmitry; Babanin, Alexander V.

2014-09-01