Materials Literature
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Two types of divacancy at the (001) surface of MgO are theoretically studied and compared with the corresponding defect in the bulk: the pit, where a surface magnesium and the oxygen ion underneath are removed, and the tub, where both removed ions are at the surface. All calculations have been performed by means of th…
Solid-state MAS NMR and synchrotron X-ray powder diffraction have been used to study the reactivity and structure of Zn 2+ -exchanged NaX. Dehydrated ZnX with a Zn:Na ratio of 3.6:1 was refined in the space group Fd 3 m . The zinc cations were located in four distinct positions all along the [111] direction. Residual…
The frequency-dependent vibrational second hyperpolarizability of CH4−nFn molecules with n=0–4 has been computed for the most common nonlinear optical (NLO) processes by adopting the perturbation approach due to Bishop and Kirtman [J. Chem. Phys. 95, 2646 (1991)]. These calculations have been performed by using the Sa…
Polyhydroxyalkanoate synthase (PHA) from Chromatium vinosum catalyzes the conversion of 3-hydroxybutyryl-CoA (HB-CoA) to polyhydroxybutyrate (PHB) and CoA. The synthase is composed of a approximately 1:1 mixture of two subunits, PhaC and PhaE. Size-exclusion chromatography indicates that in solution PhaC and PhaE exis…
New azobenzene-linked diporphyrin Zn complexes and free base analogues were synthesized in an attempt to develop new materials for molecular electronics. These diporphyrin Zn complexes and the corresponding diporphyrins consist of electron-deficient porphyrin Zn complex and electron-rich porphyrin Zn complex or electr…
In this paper we present time-dependent density functional calculations on frequency-dependent first (β) and second (γ) hyperpolarizabilities for the set of small molecules, N2, CO2, CS2, C2H4, NH3, CO, HF, H2O, and CH4, and compare them to Hartree–Fock and correlated ab initio calculations, as well as to experimental…
We have examined theoretically the spontaneous thinning process of tip-suspended nanowires, and subsequently studied the structure and stability of the monatomic gold wires recently observed by Transmission Electron Microscopy (TEM). The methods used include thermodynamics, classical many-body force simulations, Local…
An accurate determination of frequency-dependent molecular hyperpolarizabilities is at the same time of possible technological importance and theoretically challenging. For large molecules, Hartree–Fock theory was until recently the only available ab initio approach. However, correlation effects are usually very impor…
Block copolymer micelles (polymer−metal complex micelles) containing platinum(II) complexes in the core were prepared through the complexation of cis -dichlorodiammineplatinum(II) (cisplatin, CDDP) with poly(ethylene glycol)−poly(α,β-aspartic acid) block copolymer (PEG−P(Asp)) in an aqueous medium. Dynamic light scatt…
The electronic structure and the chemical bonding mechanism of silver oxide are studied on the basis of band-structure calculations, using the full-potential linearized augmented-plane-wave (FLAPW) method. Our calculations indicate that silver oxide is a metal (or a semi-metal). Total and partial densities of states a…
The simultaneous application of low intensity optical and static electric fields to photoisomerizable electro-optic materials is shown to allow manipulation of the refractive index. A dc electric field was applied to the sample by means of a corona poling mechanism, which was illuminated within the absorption band usi…
Polyvinylalcohol (PVA) films, filled with mass fractions % of , were prepared. The x-ray diffraction spectra indicated the partial crystallinity of PVA, which decays as w increases. The infrared analysis implied that the degree of syndiotacticity depends, nonmonotonically, on w . The observed peak at 520 nm, in the ul…
We prepared oxygen stoichiometric and in which tetravalent terbium ions are stabilized at the B sites of the perovskite . Their crystal structures at room temperature and at 10 K were determined from both x-ray and neutron diffraction measurements. Both and have an orthorhombic perovskite-type structure with space gro…
La and Nd gallates are currently being used as substrate materials for high temperature superconductor thin film deposition. In this work we have synthesized and characterized by means of XRD and Raman spectroscopy solid solutions of the type . Polarized Raman study of and single crystals is also performed. Our result…
The 2-orbital Kondo model with classical Jahn-Teller phonons is studied using Monte Carlo techniques. The observed phase diagram is rich and includes a novel regime of phase separation induced by the orbital degrees of freedom. Experimental consequences of our results are discussed. In addition, the optical conductivi…
Pinning type coercivity has been induced in large $(\ensuremath{\approx}50\ensuremath{\mu}\mathrm{m})$ particles of $\mathrm{Sm}{}_{2}\mathrm{Fe}{}_{17}\mathrm{N}{}_{3}$ by irradiation with 5 GeV $\mathrm{Pb}{}^{56+}$ ions. M\"ossbauer spectroscopy is used to analyze the structure of the defects and estimate their vol…
In this work, we present results from a ball-milling experiment carried out simultaneously on (a) spinel and (b) its precursor mixture , to investigate their evolution under identical conditions. Partial reversibility of the reaction was observed, resulting in nearly equal phase composition for both systems after 420…
Carbon nitride particles of nm size were prepared in an induction thermal plasma treatment of carbon powder including a small amount of nitrogen. Relatively large ones of about 5 nm in diameter are mostly in a dodecahedral shape. The structure was analyzed by high-resolution transmission electron microscopy and electr…
A thin (∼2 nm thick) amorphous diamond coating was prepared on single crystal silicon tip arrays by using a filtered vacuum arc plasma deposition technique. The coating has a microscopically uniform morphology. As compared to uncoated tips, the electron emission of the coated tip arrays is enhanced, showing an increas…
Ambipolar carrier transport properties in different phases of a liquid-crystalline photoconductor, 2-(4-octylphenyl)–6-n-butoxynaphthalene, were investigated by a time-of-flight technique. Carrier mobilities were increased stepwise when phase transition took place as the temperature decreased. The smectic E phase in t…