Materials Literature
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The sequential growth of small titanium clusters with up to 15 atoms and the dissociative chemisorption of H 2 on the minimum energy clusters have been studied within density functional theory under the generalized gradient approximation. It has been found that the low-energy clusters grow three dimensionally from Ti…
The performance parameters of Ni 0.5 Zn 0.5 Fe 2 O 4 , synthesized in the nanocrystalline form by an autocombustion method, have been investigated. The sample sintered at 1200°C, with Bi 2 O 3 as additive shows a very high value of initial permeability μ′ i of >400 at 1 MHz, with low loss. Similarly, a very high di…
Dependence of the permittivity of single-walled and multiwalled carbon nanotube composites on frequency and concentration was investigated experimentally using the coaxial air-line method over 0.1–10 GHz. The results are in good agreement with that obtained using the impedance method. It is found that scaling law base…
We have prepared a zinc chlorophyll (ZC) derivative that self-assembles into a cyclic tetramer as evidenced by small-angle X-ray scattering studies in solution using a synchrotron source. This cyclic tetramer exhibits intramolecular energy transfer rates determined from singlet−singlet annihilation and transient absor…
Electronic tuning and syntheses to gain the icosahedral quasicrystal (i-QC) (Ca14.1(2)Au44.2(8)In41.7(7), e/a = 1.98) and two approximant crystals (ACs) are reported. The tuning was derived from Na2Au6In5, another cubic Mg2Zn11-type structure, for which the Fermi level (e/a = 1.77) should tune to a calculated pseudoga…
Tower-like ZnO structures have been prepared by a simple carbon thermal reduction method and the possible growth mechanism of such structures was discussed. Comparing with microrods and nanowires, the photoluminescence images and spectra of tower-like ZnO were examined to understand the origins of their visible emissi…
This work investigates the removal of nitrobenzene (NB), a model pollutant from water, by combining adsorption onto zeolites and regeneration with ozone. The adsorption equilibrium isotherms of NB onto zeolites enabled the best adsorbent to be selected and zeolites with a high Si/Al ratio were the most efficient. The…
A generalized coupled-mode approach of metamaterial coupled-line couplers is presented. This approach is an extension of the traditional coupled-mode theory (CMT) to the cases of arbitrary types of conventional or metamaterial couplers with lines represented by the most general composite right/left-handed (CRLH) trans…
Labeling cells with iron oxide is a useful tool for MRI based cellular imaging. Here it is demonstrated that peripheral rat T cells can be labeled in whole blood, in vitro, with streptavidin-coated micron-sized iron oxide particles (MPIOs), achieving iron concentrations as high as 60 pg iron per cell. This is 30 times…
Our micromagnetic calculation demonstrates that the dominant coercivity mechanism is self-pinning in most exchange-coupled permanent and composite magnets. Such a pinning is attributed to the change of the intrinsic parameters associated with the phase change at the interface. From this self-pinning some more specific…
In this study, anionic gadofullerene {Gd@C60[C(COOH)2](10)} was used as an in vitro cellular magnetic resonance imaging label. The cellular uptake characteristics of this gadofullerene were significant and nonspecific, and excellent labeling efficiency (98-100%) was achieved without a transfecting agent. The average u…
In this report, we describe a novel solvothermal procedure for the synthesis of nanosized particles of barium titanate (BaTiO 3 ). We have been able to synthesize large amounts of nearly uniform sized BaTiO 3 nanocrystals in the size range of 5−37 nm. The advantages of our technique over other previously reported hydr…
Abstract This paper describes experiments in which mechanisms of crystal growth are inferred from the surface nanotopography of natural and synthetic dolomite using atomic force and scanning electron microscopy. Synthetic dolomite was formed by replacement of calcite at 218°C in Mg–Ca–Cl solutions. The first products…
Magnetic and magnetoelastic properties of a series of Ga-substituted cobalt ferrites, CoGaxFe2−xO4 (x=0.0–0.8), have been investigated. The Curie temperature TC and hysteresis properties were found to vary with gallium content (x), which indicates that exchange and anisotropy energies changed as a result of substituti…
The kinetics of 18O/16O isotopic exchange over CeO2-ZrO2-La2O3 and Pt/CeO2-ZrO2 catalysts have been investigated under the conditions of dynamic adsorption-desorption equilibrium at atmospheric pressure and a temperature range of 650-850 degrees C. The rates of oxygen adsorption-desorption on Pt sites, support surface…
The selective production of long, horizontally aligned carbon nanotubes (>1 mm) or short, randomly oriented carbon nanotubes (<50 μm) was achieved in a chemical vapor deposition process by influencing the catalyst pretreatment and reaction conditions. A detailed investigation was undertaken to elucidate the mechanism…
Polycrystalline BiFeO3 film has been fabricated by a chemical solution deposition on Pt∕Ti∕SiO2∕Si(100) substrates. A ferroelectric hysteresis loop showed a high remanent polarization of 47μC∕cm2 at room temperature. Leakage current density was on the order of 10−1A∕cm2 at 100kV∕cm, indicating the high leakage current…
Alumina thin films were manufactured from aqueous slurries by dip coating. Film thickness as function of substrate withdrawal velocity could be correctly modeled by Landau and Levich's theory. Samples were sintered on a rigid substrate at 1350°C for different isothermal times to achieve relative densities from 84% to…
Several commercial high density ferroelectric random access memory (FeRAM) devices utilize stacks of submicron lead zirconate-titanate (PZT) capacitors. The low-field electrical characteristics of these capacitors display a specific frequency dependence which is best represented by a constant phase element (CPE) in th…
The magnetic, magnetocaloric, and magnetoresistive properties of the polycrystalline compound HoNiAl have been studied. The temperature variations of magnetization and heat capacity show that the compound undergoes two magnetic transitions, one at 14K and the other at 5K. The former is due to the paramagnetic-ferromag…