Phase separation and valence instabilities in cuprate superconductors. Effective one-band model approach. Abstract We study the Cu-O valence instability (VI) and the related phase separation (PS) driven by Cu-O nearest-neighbor repulsion U pd , using an effective extended one-band Hubbard model (H ef f) obtained from the extended three-band Hubbard model, through an appropriate low-energy reduc...

The electronic structures of BiOX (X = F, Cl, Br, I) photocatalysts have been calculated with and without Bi 5d states using the experimental lattice parameters, via the plane-wave pseudopotential method based on density functional theory (DFT). BiOF exhibits a direct band gap of 3.22 or 3.12 eV corresponding to the adoption of Bi 5d states or not. The indirect band gaps of BiOCl, BiOBr, and Bi...

We utilized a thermal radiation method to synthesize semiconducting hollow ZnO nanoballoons and metal-semiconductor concentric solid Zn/ZnO nanospheres from metallic solid Zn nanospheres. The chemical properties, crystalline structures, and photoluminescence mechanisms for the metallic solid Zn nanospheres, semiconducting hollow ZnO nanoballoons, and metal-semiconductor concentric solid Zn/ZnO ...

The mechanism underlying temporal correlations among blood oxygen level-dependent signals is unclear. We used oxygen polarography to better characterize oxygen fluctuations and their correlation and to gain insight into the driving mechanism. The power spectrum of local oxygen fluctuations is inversely proportional to frequency raised to a power (1/f) raised to the beta, with an additional posi...

Several recent articles [l]-[3] have discussed the use ofLagrange polynomials for band-limited signal estimation. We find errorbounds when using Lagrange polynomials for interpolation and extra-polation of finite-power band-limited signals if a finite number of regularlyspaced noisy samples are used. I. INTR~DUC~ONSuppose f(t) has a (2N + 1)st derivative and the samplesf...

Most radiation therapy machines are based on microwave linear accelerators. The majority of medical accelerators use frequencies in the S-band range. Having a compact accelerator allows for a wide range of treatments. The size and weight of the accelerator is substantially reduced if a higher frequency is used. X-band frequencies are suitable for such applications. The X-band accelerator techno...

fusarium wilt of chickpea, caused by f. oxysporum f. sp. ciceris, is one of the most important diseases of this plant in iran. in order to control this disease, fluorescent pseudomonads were isolated from the rhizosphere of chickpea plants in khorasan province by using king,s b medium (kb). antifungal activity of 80 bacterial strains against f. oxysporum f. sp. ciceris was evaluated on kb and p...

We discuss the electronic quasiparticle spectrum of a ferromagnetic semiconductor, within the framework of the s-f model. Some exactly calculable limi ting cases (ferromagnetic saturation, atomic limit, centre of gravity of the conduction band, ....) as well as approximate theories for the general case are reviewed in order to understand the influence of temperature and finite band filling on t...

Four novel receptors were designed and synthesized for colorimetric detection of F− ions. The introduction of four electron withdrawing groups into the backbone of the receptors makes the two phenolic groups efficient hydrogen bonding sites. The binding properties of receptors with anions were examined for the first time by UV–Vis, 1H NMR and fluorescence spectroscopies. The addition of F− resu...