Materials Literature
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Photoluminescence and cathodoluminescence (CL) spectra of stoichiometric and oxygen-deficient ZnO films grown on sapphire were examined. It was found that the intensities of the green and yellow emissions depend on the width of the free-carrier depletion region at the particle surface; the thinner the width, the large…
The reaction of Cu and V in a Rb(2)S(5) melt yields black crystals of rubidium dicopper vanadium tetrasulfide, RbCu(2)VS(4). The structure is comprised of [Cu(2)VS(4)](-) layers within the (010) plane which are separated by Rb(+) cations. The layers consist of a network of edge- and corner-sharing [VS(4)] and [CuS(4)]…
The low-temperature ferromagnetic insulator (FMI) phase of La 1- x Sr x MnO 3 ( x =0.11, 0.12) was investigated by convergent-beam electron diffraction (CBED) together with selected-area electron diffraction (SAED). We have revealed that the FMI phase belongs to the triclinic space group P\bar1, and has a unit cell of…
A Mn2+ ion-doped β-Ga2O3 single crystal was grown by using a floating zone method. By employing an X-band electron paramagnetic resonance (EPR) spectrometer, Mn2+ EPR spectra were recorded at room temperature. The rotation patterns in the crystallographic planes together with spin-Hamiltonian parameters of Mn2+ show u…
The first molecular hyperpolarizabilities (β) of a series of charge-transfer nonlinear optical (NLO) chromophores are measured with the hyper-Rayleigh scattering (HRS) technique using two excitation wavelengths at 1064 and 1907 nm. The 1907 nm wavelength is the longest excitation wavelength used for the HRS experiment…
This theory shows that, as the ratio of the grain sizes increases, the boundary between the grains becomes more highly curved and the smaller grain becomes more deeply embedded in the larger one. At a ratio of only 1.57, the exposed portion of the small grain is too small to allow it to bond to a third, larger grain,…
Transient absorption anisotropies of the Zn(II)porphyrin monomer, its direct meso–meso coupled dimer, and trimer are measured in the B (Soret) band region by sub-30 fs laser pulses. It is shown that detailed information on the electronic structures and energy transfer dynamics can be obtained from the anisotropy and t…
Diffraction gratings were studied in cells of the homogeneously aligned liquid-crystal E7 doped with multiwall carbon nanotubes. These phase gratings were induced by interference modulation of two coherent optical beams, in conjunction with an applied dc field that was perpendicular to the unperturbed director axis. S…
Monodisperse long-chain alkanes such as C198H398 form lamellar crystals in both extended- and folded-chain forms. Folded-chain crystals are in a meta-stable equilibrium with polymer solution at a concentration CF. The crystal growth rate is virtually zero at this point, due to the self-poisoning phenomenon. If extende…
Epitaxial Pb(ZrxTi1−x)O3 films with (001) and (100), (101) and (110), and (111) orientations were grown on (100)SrRuO3//(100)SrTiO3, (110)SrRuO3//(110)SrTiO3, and (111)SrRuO3//(111)SrTiO3 substrates, respectively. The two composition films with Zr/(Zr+Ti) ratios of 0.42 and 0.68 were prepared with the Pb/(Pb+Zr+Ti) ra…
Antiferroelectric materials (example: lead zirconate and modified lead zirconate stannate), in which a field-induced ferroelectric phase transition is feasible due to a small free energy difference between the ferroelectric and the antiferroelectric phases, are proven to be very good candidates for applications involv…
The compounds MnN and FeN were prepared as single phase sample by DC reactive sputtering. The crystal structure of MnN is tetragonally distorted NaCl type and that of FeN is ZnS type. Temperature dependence of the neutron diffraction pattern on MnN was investigated. Analysis of the data shows that the magnetic structu…
The crystallization of amorphous Ge(a-Ge) in an Al (134 nm) and a-Ge (108 nm) thin-film bilayer deposited on a SiO2 substrate has been examined by a cross section transmission electron microscope technique. When crystallization of a-Ge begins at 125 °C, amorphous AlGe (a-AlGe) alloy is formed in the Ge layer. Then, th…
Collapsed multiwalled carbon nanotube (MWCNT) sections and segments (carbon nanotube ribbons) on surfaces were observed by atomic-force microscopy. The collapsed form of these MWCNTs allowed the determination of the layer number and the inner and outer diameters for their uncollapsed form. The results show that such c…
The class 1 integron integrase, IntI1, recognizes two distinct types of recombination sites, attI sites, found in integrons, and members of the 59-be family, found in gene cassettes. The efficiencies of the integrative version of the three possible reactions, i.e., between two 59-be, between attI1 and a 59-be, or betw…
Fullerene soot with a high content of single-wall carbon nanotubes was tested to assess its potential biochemical activity. The results of dermatological trials did not show any signs of health hazard related to skin irritation and allergic risks.
To determine whether carbon nanotubes can induce any significant health hazards we applied methods routinely used in the pathophysiological testing of asbestos-induced disease to show that the soot with a high content of CNTs does not induce any abnormalities of pulmonary function or measurable inflammation in guinea…
Frequency dispersion associated with dielectric relaxation phenomena in polycrystalline cubic pyrochlore with normal composition (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7 is analyzed. Measurements at cryogenic temperatures and high frequencies reveal a broad distribution of relaxation times. The associated dielectric loss data can b…
When a suspension consisting of dielectric particles having nonlinear characteristics is subjected to a sinusoidal (ac) field, the electrical response will in general consist of ac fields at frequencies of the higher-order harmonics. These ac responses will also be anisotropic. In this work, a self-consistent formalis…
We report the synthesis of cyclophanes 18-20 by ester-forming macrocyclization reactions of diols 15 and 16 with 1,4-benzenedicarbonyl chloride. Compounds 18 and 19 display a two-electron, quasireversible oxidation wave in the cyclic voltammogram to yield the dication species at E(ox)(pa) 0.52 and 0.47 V, respectively…