Assembly of one-dimensional organic luminescent nanowires based on quinacridone derivatives

The quinacridone derivatives N,N'-dialkyl-1,3,8,10-tetramethylquinacridone (CnTMQA, n = 6, 10, 14) were used as building blocks to assemble luminescent nano- and microscale wires. It was demonstrated that CnTMQA with different lengths of alkyl chains display obviously different wire formation properties. C10TMQA and C14TMQA showed a stronger tendency to form 1-D nano- and microstructures compared with C6TMQA. The C10TMQA molecules could be employed to fabricate the wires with different diameters, which exhibited a size-dependent luminescence property. The emission spectrum of the C10TMQA wires with diameters of 200-500 nm shows a broad emission band at 560 nm and a shoulder at around 535 nm, while the emission spectrum of the C10TMQA wires with diameters of 2-3 mu m reveals a narrower emission band at 563 nm. For the CnTMQA-based samples with different morphologies, the emission property change tendency agrees with that of the powder X-ray diffraction patterns of these samples.

Rapid self-assembly of oligo(o-phenylenediamine) into one-dimensional structures through a facile reprecipitation route

The self-assembly of oligo(o-phenylenediamine) (OPD) into 1-D nanostructures on a macroscopic length scale was found when they were transferred from N-methyl pyrrolidone to deionized water. Field emission scanning electron microscopy and confocal fluorescence microscopy were used to investigate the morphology of the precipitates. Results showed that large amounts of OPD 1-D supertructures could be obtained through the simple reprecipitation route, and the length of the fibers could be tuned from microscale to macroscale by adjusting the ratio of two solvents. X-ray diffraction patterns and UV-vis spectra revealed that pi-pi interactions between OPD molecules that facilitated the formation of 1-D structures became predominant when they were transferred from a good solvent to a bad one. Accordingly, a possible formation mechanism was proposed.

Hydrothermal synthesis, structure, and characterization of two one-dimensional chainlike hybrid complexes [(CuX)(2)(o-phen)](infinity) (X = Br, Cl; o-phen = o-phenanthroline)

Two novel organic-inorganic hybrid complexes [(CuX)(2)(o-phen)](infinity) (X = Br (1), Cl (2); o-phen = o-phenanthroline) have been synthesized hydrothermally and characterized structurally by elemental analyses, IR, ESR, XPS spectrum, TG analyses and single-crystal X-ray diffraction. Both title compounds exhibit novel one-dimensional chainlike copper halide scaffolding constructed by the unusual [Cu3X3] hexagon motifs by sharing opposite edges, where a single Cu site of each [Cu3X3] hexagon is chelated with N donors of o-phen group. To our knowledge, such basic o-phen-copper halide skeleton has not been reported hitherto. Moreover, TG analyses indicate that both title compounds possess high thermal stability.

Novel hydrogen-bonded three-dimensional networks encapsulating one-dimensional covalent chains: [M(4,4 '-bipy)(H2O)4](4-abs)2 center dot nH(2)O (4,4 '-bipy=4,4 '-Bipyridine; 4-abs=4-aminobenzenesulfonate) (M=Co, n=1; M=Mn, n=2)

Two novel compounds, [Co(4,4'-bipy)(H2O)(4)](4-abS)(2).H2O (1) and [Mn(4,4'-bipy)(H2O)(4)](4-abs)(2).2H(2)O (2) (4,4'-bipy = 4,4'-bipyridine; 4-abs = 4-aminobenzenesulfonate), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, UV-vis and IR spectra, and TG analysis. X-ray structural analysis revealed that 1 and 2 both possess unusual hydrogen-bonded three-dimensional (3-D) networks encapsulating one-dimensional (1-D) covalently bonded infinite [M(4,4'-bipy)(H2O)(4)](2+) (M = Co, Mn) chains. The 4-abs anions in 1 form 1-D zigzag chains through hydrogen bonds. These chains are further extended through crystallization water molecules into 3-D hydrogen-bonded networks with 1-D channels, in which the [Co(4,4'-bipy)(H2O)(4)](2+) linear covalently bonded chains are located. Crystal data for 1: C22H30CoN4O11S2, monoclinic P2(1), a = 11.380(2) Angstrom, b = 8.0274(16) Angstrom, c = 15.670(3) Angstrom, alpha = gamma = 90degrees, beta = 92.82(3)degrees, Z = 2. Compound 2 contains interesting two-dimensional (2-D) honeycomb-like networks formed by 4-abs anions and lattice water molecules via hydrogen bonding, which are extended through other crystallization water molecules into three dimensions with 1-D hexagonal channels. The [Mn(4,4'-bipy)(H2O)(4)](2+) linear covalent chains exist in these channels. Crystal data for 2: C22H32WN4O12S2, monoclinic P2(1)/c, a = 15.0833(14) Angstrom, b = 8.2887(4) Angstrom, c = 23.2228(15) Angstrom, alpha = gamma = 90degrees, beta = 95.186(3)degrees, Z = 4.

An organic-inorganic vanadium oxide with one-dimensional ladder-type structure: hydrothermal synthesis, structure and characterization of [V4O10(o-phen)(2)]

A novel organic-inorganic hybrid vanadium oxide [V4O10(o-phen)(2)], involving all vanadium atoms present in +5 oxidation, has been hydrothermally synthesized and characterized by elemental analysis, IR, UV-vis, ESR, XPS spectra and TG-DTA thermal analysis. The single-crystal X-ray diffraction shows that the red-brown crystal is formed in the triclinic system, space group P (1) over bar, a = 9.782(2), b = 6.5124(14), c = 19.765(4) Angstrom, alpha = 89.94(2)degrees, beta = 100.66(2)degrees, gamma = 89.86(2)degrees. The title compound exhibits an infinite one-dimensional ladder-type tetravanadate skeleton with organonitrogen donors of o-phenanthroline ligands coordinated directly to the vanadium oxide framework.

The luminescence of the phosphor Sr2ZrO4 with one-dimensional chains structure

A new type of phosphor Sr2ZrO4 with one-dimensional structure was prepared by solid reaction and its luminescence is seen at room temperature. The excitation and emission spectra were measured and display broad maximum at 354 nm and 386 nm respectively. The mechanism of this luminescence is ascribed to charge transfer.

Precise solutions of the one-dimensional Monge-Kantorovich problem

Plakhov, A.Y., (2004) 'Precise solutions of the one-dimensional Monge-Kantorovich problem', Sbornik: Mathematics 195(9) pp.1291-1307 RAE2008

Possible Exotic Phases in the One-Dimensional Extended Hubbard Model

We investigate numerically the ground state phase diagram of the one-dimensional extended Hubbard model, including an on--site interaction U and a nearest--neighbor interaction V. We focus on the ground state phases of the model in the V >> U region, where previous studies have suggested the possibility of dominant superconducting pairing fluctuations before the system phase separates at a critical value V=V_PS. Using quantum Monte Carlo methods on lattices much larger than in previous Lanczos diagonalization studies, we determine the boundary of phase separation, the Luttinger Liquid correlation exponent K_rho, and other correlation functions in this region. We find that phase separation occurs for V significantly smaller than previously reported. In addition, for negative U, we find that a uniform state re-enters from phase separation as the electron density is increased towards half filling. For V < V_PS, our results show that superconducting fluctuations are not dominant. The system behaves asymptotically as a Luttinger Liquid with K_rho < 1, but we also find strong low-energy (but gapped) charge-density fluctuations at a momentum not expected for a standard Luttinger Liquid.

Ergodicity and Mixing Rate of One-Dimensional Cellular Automata

One-and two-dimensional cellular automata which are known to be fault-tolerant are very complex. On the other hand, only very simple cellular automata have actually been proven to lack fault-tolerance, i.e., to be mixing. The latter either have large noise probability ε or belong to the small family of two-state nearest-neighbor monotonic rules which includes local majority voting. For a certain simple automaton L called the soldiers rule, this problem has intrigued researchers for the last two decades since L is clearly more robust than local voting: in the absence of noise, L eliminates any finite island of perturbation from an initial configuration of all 0's or all 1's. The same holds for a 4-state monotonic variant of L, K, called two-line voting. We will prove that the probabilistic cellular automata Kε and Lε asymptotically lose all information about their initial state when subject to small, strongly biased noise. The mixing property trivially implies that the systems are ergodic. The finite-time information-retaining quality of a mixing system can be represented by its relaxation time Relax(⋅), which measures the time before the onset of significant information loss. This is known to grow as (1/ε)^c for noisy local voting. The impressive error-correction ability of L has prompted some researchers to conjecture that Relax(Lε) = 2^(c/ε). We prove the tight bound 2^(c1log^21/ε) ＜ Relax(Lε) ＜ 2^(c2log^21/ε) for a biased error model. The same holds for Kε. Moreover, the lower bound is independent of the bias assumption. The strong bias assumption makes it possible to apply sparsity/renormalization techniques, the main tools of our investigation, used earlier in the opposite context of proving fault-tolerance.

CFD analysis of one-dimensional infiltration in vadose zone

This study presents a CFD analysis constructed around PHYSICA, an open framework for multi-physics computational continuum mechanics modelling, to investigate the water movement in unsaturated porous media. The modelling environment is based on a cell-centred finite-volume discretisation technique. A number of test cases are performed in order to validate the correct implementation of Richard's equation for compressible and incompressible fluids. The pressure head form of the equation is used together with the constitutive relationships between pressure, volumetric water content and hydraulic conductivity described by Haverkamp and Van Genuchten models. The flow problems presented are associated with infiltration into initially dry soils with homogeneous or layered geologic settings. Comparison of results with the problems selected from literature shows a good agreement and validates the approach and the implementation.

Green function for the diffusion limit of one-dimensional continuous time random walks

It is shown how the fractional probability density diffusion equation for the diffusion limit of one-dimensional continuous time random walks may be derived from a generalized Markovian Chapman-Kolmogorov equation. The non-Markovian behaviour is incorporated into the Markovian Chapman-Kolmogorov equation by postulating a Levy like distribution of waiting times as a kernel. The Chapman-Kolmogorov equation so generalised then takes on the form of a convolution integral. The dependence on the initial conditions typical of a non-Markovian process is treated by adding a time dependent term involving the survival probability to the convolution integral. In the diffusion limit these two assumptions about the past history of the process are sufficient to reproduce anomalous diffusion and relaxation behaviour of the Cole-Cole type. The Green function in the diffusion limit is calculated using the fact that the characteristic function is the Mittag-Leffler function. Fourier inversion of the characteristic function yields the Green function in terms of a Wright function. The moments of the distribution function are evaluated from the Mittag-Leffler function using the properties of characteristic functions and a relation between the powers of the second moment and higher order even moments is derived. (C) 2004 Elsevier B.V. All rights reserved.

One-dimensional particle simulation of the filamentation instability: Electrostatic field driven by the magnetic pressure gradient force

Two counterpropagating cool and equally dense electron beams are modeled with particle-in-cell simulations. The electron beam filamentation instability is examined in one spatial dimension, which is an approximation for a quasiplanar filament boundary. It is confirmed that the force on the electrons imposed by the electrostatic field, which develops during the nonlinear stage of the instability, oscillates around a mean value that equals the magnetic pressure gradient force. The forces acting on the electrons due to the electrostatic and the magnetic field have a similar strength. The electrostatic field reduces the confining force close to the stable equilibrium of each filament and increases it farther away, limiting the peak density. The confining time-averaged total potential permits an overlap of current filaments with an opposite flow direction.

Structural changes in quasi-one-dimensional many-electron systems: From linear to zigzag and beyond

Many-electron systems confined to a quasi-one-dimensional geometry by a cylindrical distribution of positive charge have been investigated by density functional computations in the unrestricted local spin density approximation. Our investigations have been focused on the low-density regime, in which electrons are localized. The results reveal a wide variety of different charge and spin configurations, including linear and zig-zag chains, single-and double-strand helices, and twisted chains of dimers. The spin-spin coupling turns from weakly antiferromagnetic at relatively high density, to weakly ferromagnetic at the lowest densities considered in our computations. The stability of linear chains of localized charge has been investigated by analyzing the radial dependence of the self-consistent potential and by computing the dispersion relation of low-energy harmonic excitations.

Modelling the mechanical response of the Reed-mouthpiece-lip system of a clarinet. Part I. A one-dimensional distributed model

The motion of a clarinet reed that is clamped to a mouthpiece and supported by a lip is simulated in the time-domain using finite difference methods. The reed is modelled as a bar with non-uniform cross section, and is described using a one-dimensional, fourth-order partial differential equation. The interactions with the mouthpiece Jay and the player's lip are taken into account by incorporating conditional contact forces in the bar equation. The model is completed by clamped-free boundary conditions for the reed. An implicit finite difference method is used for discretising the system, and values for the physical parameters are chosen both from laboratory measurements and by accurate tuning of the numerical simulations. The accuracy of the numerical system is assessed through analysis of frequency warping effects and of resonance estimation. Finally, the mechanical properties of the system are studied by analysing its response to external driving forces. In particular, the effects of reed curling are investigated.