Search results for "BIP"
showing 10 items of 1908 documents
Superlight small bipolarons from realistic long-range Coulomb and Fröhlich interactions
2011
We report analytical and numerical results on the two-particle states of the polaronic t-Jp model derived recently with realistic Coulomb and electron-phonon (Frohlich) interactions in doped polar insulators. Eigenstates and eigenvalues are calculated for two different geometries. Our results show that the ground state is a bipolaronic singlet, made up of two polarons. The bipolaron size increases with increasing ratio of the polaron hopping integral t to the exchange interaction Jp but remains small compared to the system size in the whole range 0<t/Jp<1. Furthermore, the model exhibits a phase transition to a superconducting state with a critical temperature well in excess of 100K. In the…
Controlling the thermoelectric properties of polymers: application to PEDOT and polypyrrole
2015
Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films have been prepared by an electrochemical method in a three electrode cell. The films have been obtained at different oxidation levels regarded as bipolaron, polaron and neutral states by varying the voltage, as is usually done in conjugated heterocyclic polymers. The voltage (-0.2V1.0 V) has been applied versus a Ag/AgCl reference electrode, producing a variation of one order of magnitude in the electrical conductivity and the Seebeck coefficient of the films. In the voltage range explored, the electrical conductivity increases from 80 to 766 S cm(-1) in PEDOT and from 15 to 160 S cm(-1) in PPy, while the Seebeck coefficie…
Tuning Of Organic Heterojunction Conductivity By The Substituents' Electronic Effects In Phthalocyanines For Ambipolar Gas Sensors
2021
Abstract Exploiting organic heterojunction effects in electrical devices are an important strategy to improve the electrical conductivity, which can be utilized into improving the conductometric gas sensors performances. In this endeavor, the present article reports fabrication of organic heterostructures in a bilayer device configuration incorporating octa-substituted nickel phthalocyanines (NiPc) and radical lutetium bis-phthalocyanine (LuPc2) and investigates their sensing properties towards NH3 vapor. NiPc having hexyl sulfanyl, hexyl sulfonyl and p-carboxyphenoxy moieties are synthesized, which electronic effects are electron donating, accepting and moderate accepting, respectively, al…
Stationary states in quantum walk search
2016
When classically searching a database, having additional correct answers makes the search easier. For a discrete-time quantum walk searching a graph for a marked vertex, however, additional marked vertices can make the search harder by causing the system to approximately begin in a stationary state, so the system fails to evolve. In this paper, we completely characterize the stationary states, or 1-eigenvectors, of the quantum walk search operator for general graphs and configurations of marked vertices by decomposing their amplitudes into uniform and flip states. This infinitely expands the number of known stationary states and gives an optimization procedure to find the stationary state c…
Analyses of known and new types of polyhalogenated aromatic substances in oven ash from recycled aluminium production
2003
Abstract Persistent aromatic bromine, chlorine and mixed chlorine-bromine compounds were analysed from recycled aluminium smelter (ALS) ashes to explore the impact of brominated flame retardants (BFR) on their formation. Polybrominated diphenyl ethers (PBDE) were the most abundant original BFRs found. Induction furnace ash contained tetra- to octa-BDEs about 2000 ng g −1 in similar congener ratios as the original scrap, but contents of nona- and deca-BDEs were only 25 and 5 ng g −1 indicating their significant degradation in ALS process. In the most non-polar fraction, PCB levels and profiles were similar as earlier ALS ash samples in 1990s. The highest PCB level measured was that of deca-C…
Organochlorine Pesticides and Polychlorinated Biphenyl Congeners in LannerFalco biarmicus feldeggiiSchlegel Chicks and Lanner Prey in Sicily, Italy
2008
This paper reports on research conducted to elucidate the risk posed to the Sicilian population of the endangered lanner falcon Falco biarmicus feldeggii Schlegel by organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), as part of a wider study on contaminant risk to the lanner. Seventeen lanner nest sites were studied in northern and central Sicily. Sampling (in 2005) and analysis were carried out for selected OC pesticides and PCB congeners in lanner chick blood (15 chicks from 6 nest sites) and in two of the main lanner prey species, magpie Pica pica (36 individuals from 6 lanner nest sites) and rock dove Columba livia (10 individuals from 2 lanner nest sites). No OC and P…
Cooperative Spin Transition in the Two-Dimensional Coordination Polymer [Fe(4,4′-bipyridine)2(NCX)2]·4CHCl3 (X = S, Se)
2011
Two new isostructural two-dimensional (2D) coordination polymers exhibiting spin crossover (SCO) behavior of formulation [Fe(4,4'-bipy)(2)(NCX)(2)]·4CHCl(3) (4,4'-bipy = 4,4'-bipyridine; X = S [1·4CHCl(3)], Se [2·4CHCl(3)]) have been synthesized and characterized, and both undergo cooperative spin transitions (ST). For 1·4CHCl(3) the ST takes place in two steps with critical temperatures of T(c1)(down) = 143.1 K, T(c2)(down) = 91.2 K, T(c1)(up) = 150.7 K, and T(c2)(up) = 112.2 K. 2·4CHCl(3) displays half ST characterized by T(c)(down) = 161.7 K and T(c)(up) = 168.3 K. The average enthalpy and entropy variations and cooperativity parameters associated with the ST have been estimated to be ΔH…
Dimensionally controlled hydrogen-bonded nanostructures: synthesis, structure, thermal and magnetic behaviour of the tris-(chelated)nickel(II) comple…
2002
Abstract Single crystals of the compound of formula [Ni(bipy)3]Cl2·5.5H2O (bipy=2,2′-bipyridine) have been prepared and structurally characterised by X-ray diffraction. The structure analysis reveals that the complex has an approximate D3 symmetry. The coordination sphere consists of six nitrogen atoms of the three-bipyridine ligands in an octahedral arrangement about the nickel. One of the chlorine ions is surrounded by twelve CH⋯Cl hydrogen bonds. Three kinds of layers are found in the crystal structure: (i) the Λ-[Ni(bipy)3]2+ cation; (ii) the water/chloride positions (O(1w)/Cl(21) to O(7w)/Cl(27)); (iii) the Δ-[Ni(bipy)3]2+ cation and a chloride ion (Cl(1)). The layers are stacked in t…
Oxidovanadium(V) Complexes with Aminoethanol Bis(phenolate) [O,N,O,O] Ligands: Preparations, Structures, N-Dealkylation and Condensation Reactions
2011
The reactions between [VO(acac)2] (acac– = acetylacetonate ion) or [VO(OPr)3] and trianionic tetradentate N,N-bis(2-methylene-4,6-alkylphenolate)aminoethanolate ligands, [L13– (4,6-dimethyl), L23– (4-methyl, 6-tert-butyl), L33– (4-tert-butyl, 6-methyl), L43– (4,6-di-tert-butyl)], afford mononuclear complexes [VO(L1)] (1) and [VO(L2)] (2) with a trigonal bipyramidal coordination sphere around the VV ion, or dinuclear octahedral complexes [V2O2(L3)2] (3) and [V2O2(L4)2] (4). In methanol an adduct with the formula [VO(L1)(MeOH)]·1/2MeOH (5) is obtained. According to multinuclear NMR spectroscopy all those complexes have a mononuclear structure in CDCl3 solutions. In wet polar solvents complex …
Tratamiento psicofarmacológico del trastorno bipolar en América Latina
2011
Objective: This study assessed the treatment preferences among Latin-American psychiatrists for their bipolar disorder patients and if these preferences reflect the current guidelines. Methods: We designed a survey comprised of fourteen questions. All the questions were aimed at the treatment of bipolar I patients only. We distributed the survey by hand or e-mail to psychiatrists in eight different countries: Argentina, Brasil, Colombia, Costa Rica, Ecuador, México, Perú and Venezuela. Between May 2008 and June 2009, we were able to gather 1143 surveys. Results: As the initial choice of treatment for a bipolar patient who debuts with mania, 61.3% choose a combination of an atypical antipsyc…