Materials Literature
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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…
Structure and surface polarity properties of poly(vinylformamide- co -vinylamine) (PVFA- co -PVAm)/silica hybrid materials are investigated by means of electrokinetic measurements, atomic force microscopy (AFM), and solvatochromic probes. AFM measurements show the complete covering of the silica surface with the PVFA-…
Glutamate synthase is a complex iron-sulfur flavoprotein that catalyzes the reductive transfer of the L-glutamine amide group to C(2) of 2-oxoglutarate, forming two molecules of L-glutamate. The bacterial enzyme is an alphabeta protomer, which contains one FAD (on the beta subunit, approximately 50 kDa), one FMN (on t…
A novel laser photolysis source has been used to synthesize hydrogen-terminated silicon clusters Si n H x +, where n ≤ 50. Using mass spectrometry, the hydrogen content of the Si n H x + clusters with n = 10−30 was measured as a function of temperature from 300 to 950 K. For n = 10−22 at the lower temperatures, there…
Chemical modification of the argon plasma-pretreated Si(100) surface by UV-induced surface graft polymerization with either glycidyl methacrylate (GMA) or glycidyl acrylate (GA) was carried out. The GA graft polymerized Si substrate was further subjected to coupling reaction with aniline (An) and finally oxidative gra…
The study of catalytic behavior begins with one seemingly simple process, namely the hydrogenation of O to H2O on platinum. Despite the apparent simplicity its mechanism has been much debated. We have used density functional theory with gradient corrections to examine microscopic reaction pathways for several elementa…
Single crystals of Ti 2+ doped NaCl were grown by the Bridgeman technique. High resolution variable temperature absorption, continuous-wave emission, and time-dependent measurements were performed for the spectroscopic characterization of the title compound. At T < 100 K excitation of Ti 2+:NaCl in the red spectral re…
The alkali metal/group 4 metal/polychalcogenides Cs(4)Ti(3)Se(13), Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14) have been synthesized by means of the reactive flux method at 823 or 873 K. Cs(4)Ti(3)Se(13) crystallizes in a new structure type in space group…