97 research outputs found

    Energija osnovnog stanja u proŔirenom 2D Hubbardovom modelu za konačan sustav s egzaktnom dijagonalizacijom

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    Using an exact analytical diagonalization for an extended Hubbard model, we study the first nearest-neighbour repulsion effect on the behaviour of a two-dimensional system of finite size at low density of electrons. The obtained results show that the introduction of the nearest-neighbour off-site interaction allows the correlation effects to become more remarkable and to play an essential role in the electron dynamics, and this off-site interaction encourages the formation of double occupancies.Primjenom egzaktne analitičke dijagonalizacije za proÅ”iren Hubbardov model proučavamo učinak odbojne sile među prvim susjedima na svojstva konačnog dvodimenzijskog sustava pri niskim gustoćama elektrona. Postignuti ishodi pokazuju da uvođenje prvo-susjedskog međudjelovanja izvan sustava omogućuje pojačanje korelacijskih učinaka, igra bitnu ulogu u dinamici elektrona, te to međudjelovanje izvan sustava podstiče stvaranje dvostrukih popunjenja

    Energija osnovnog stanja u proŔirenom 2D Hubbardovom modelu za konačan sustav s egzaktnom dijagonalizacijom

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    Using an exact analytical diagonalization for an extended Hubbard model, we study the first nearest-neighbour repulsion effect on the behaviour of a two-dimensional system of finite size at low density of electrons. The obtained results show that the introduction of the nearest-neighbour off-site interaction allows the correlation effects to become more remarkable and to play an essential role in the electron dynamics, and this off-site interaction encourages the formation of double occupancies.Primjenom egzaktne analitičke dijagonalizacije za proÅ”iren Hubbardov model proučavamo učinak odbojne sile među prvim susjedima na svojstva konačnog dvodimenzijskog sustava pri niskim gustoćama elektrona. Postignuti ishodi pokazuju da uvođenje prvo-susjedskog međudjelovanja izvan sustava omogućuje pojačanje korelacijskih učinaka, igra bitnu ulogu u dinamici elektrona, te to međudjelovanje izvan sustava podstiče stvaranje dvostrukih popunjenja

    Extension of Self Consistent RPA method to off-site Hubbard Model

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    We are interested in the possibility that a generalization of Self Consistent Random Phase Approximation (SCRPA) to the Extended Hubbard Model can lead us to accurate estimations of the ground state energy, for closed chains in one dimension with periodic boundary conditions: N=2 (two states problem). We have considered an extended Hubbard model including on-site and off-site interactions, we have compared the SCRPA with a Direct Analytical(DA) results for the ground state energy, and have shown that SCRPA solves the two states problem exactly for any value of U (on-site interaction energy), V2 (off-site interaction energy with opposite spins) and (off-site interaction energy with same spins).We are interested in the possibility that a generalization of Self Consistent Random Phase Approximation (SCRPA) to the Extended Hubbard Model can lead us to accurate estimations of the ground state energy, for closed chains in one dimension with periodic boundary conditions: N=2 (two states problem). We have considered an extended Hubbard model including on-site and off-site interactions, we have compared the SCRPA with a Direct Analytical(DA) results for the ground state energy, and have shown that SCRPA solves the two states problem exactly for any value of U (on-site interaction energy), V2 (off-site interaction energy with opposite spins) and (off-site interaction energy with same spins)

    Self Consistent RPA applied to the extended Hubbard Model

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    Using the extended Hubbard model with the Self Consistent Random Phase Approximation (SCRPA), we study the intersite interaction effect on the dynamics of N electrons. We consider the extended Hubbard model containing intrasite and intersite interactions, and we apply this model to a system of two interacting atoms, where each atom presents one free electron. The resolution of this tow sites problem is done by the SCRPA approximation; our calculations allow as studying the intersite interaction effect on the excitation energies of system. We have showed that the attractive interaction between the electrons of the neighbourā€™s atoms is the origin of supplementary conductivity of the system.Using the extended Hubbard model with the Self Consistent Random Phase Approximation (SCRPA), we study the intersite interaction effect on the dynamics of N electrons. We consider the extended Hubbard model containing intrasite and intersite interactions, and we apply this model to a system of two interacting atoms, where each atom presents one free electron. The resolution of this tow sites problem is done by the SCRPA approximation; our calculations allow as studying the intersite interaction effect on the excitation energies of system. We have showed that the attractive interaction between the electrons of the neighbourā€™s atoms is the origin of supplementary conductivity of the system

    Assessment of Microwave/UV/O3 in the Photo-Catalytic Degradation of Bromothymol Blue in Aqueous Nano TiO2 Particles Dispersions

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    In this study, a microwave/UV/TiO2/ozone/H2O2 hybrid process system, in which various techniques that have been used for water treatment are combined, is evaluated to develop an advanced technology to treat non-biodegradable water pollutants efficiently. In particular, the objective of this study is to develop a novel advanced oxidation process that overcomes the limitations of existing single-process water treatment methods by adding microwave irradiation to maximize the formation of active intermediate products, e.g., OH radicals, with the aid of UV irradiation by microwave discharge electrodeless lamp, photo-catalysts, and auxiliary oxidants. The results of photo-catalytic degradation of BTB showed that the decomposition rate increased with the TiO2 particle dosages and microwave intensity. When an auxiliary oxidant such as ozone or hydrogen peroxide was added to the microwave-assisted photo-catalysis, however, a synergy effect that enhanced the reaction rate considerably was observed

    SNP Array Karyotyping Allows for the Detection of Uniparental Disomy and Cryptic Chromosomal Abnormalities in MDS/MPD-U and MPD

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    We applied single nucleotide polymorphism arrays (SNP-A) to study karyotypic abnormalities in patients with atypical myeloproliferative syndromes (MPD), including myeloproliferative/myelodysplastic syndrome overlap both positive and negative for the JAK2 V617F mutation and secondary acute myeloid leukemia (AML). In typical MPD cases (Nā€Š=ā€Š8), which served as a control group, those with a homozygous V617F mutation showed clear uniparental disomy (UPD) of 9p using SNP-A. Consistent with possible genomic instability, in 19/30 MDS/MPD-U patients, we found additional lesions not identified by metaphase cytogenetics. In addition to UPD9p, we also have detected UPD affecting other chromosomes, including 1 (2/30), 11 (4/30), 12 (1/30) and 22 (1/30). Transformation to AML was observed in 8/30 patients. In 5 V617F+ patients who progressed to AML, we show that SNP-A can allow for the detection of two modes of transformation: leukemic blasts evolving from either a wild-type jak2 precursor carrying other acquired chromosomal defects, or from a V617F+ mutant progenitor characterized by UPD9p. SNP-A-based detection of cryptic lesions in MDS/MPD-U may help explain the clinical heterogeneity of this disorder
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