Materials Literature
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Recent experiments have shown that heavy ion or electron irradiation induces the nucleation of diamond crystallites inside concentric nested carbon fullerenes, i.e., bucky onions. This suggests that the fullerene acts as a nanoscopic pressure shell. In this paper we study the formation of tetrahedrally bonded carbon i…
RATIONALE AND OBJECTIVES: Slow water exchange in Gd3+ complexes is generally considered detrimental to their use as MR contrast agents. The objective of this work was to demonstrate how this feature may serve as a useful template for the design of responsive MR agents. METHODS: Lanthanide (Ln) complexes of two 1,4,7,1…
The phenomenon of ant nest (formicary) corrosion is reviewed. Current theories indicate that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic acid. Morphological features are presented using several recent case studies as examples. This paper seeks…
Near-infrared (IR) spectroscopy has been used to distinguish between alumina oxo and hydroxy phases. Two near-IR spectral regions are identified for this function: (1) the high-frequency region between 6400 and 7400 cm −1 , attributed to the first overtone of the hydroxyl stretching mode, and (2) the 4000–4800 cm −1 r…
We show experimentally that spontaneous decay of highly non-equilibrium domain state in ferroelectric is achieved through the formation of self-organized nanoscale domain structures. The nanodomain structures have been observed by SEM and SFM in uniaxial ferroelectric lithium niobate during spontaneous backswitching a…
In the light of recent studies, we summarize our present theoretical understanding of insulating oxides in low dimensionality, including unsupported clusters, planar or stepped surfaces and ultrathin films. We review the various theoretical approaches, their efficiency in calculating ground and excited state propertie…
Polarization effects are studied in surface-enhanced resonant Raman scattering (SERRS) experiments on single-wall carbon nanotubes (SWNT's) in contact with silver colloidal clusters. For metallic SWNT's the very low depolarization ratio of the G band observed in normal resonant Raman scattering (RRS) is nearly complet…
Ionomers (AClyn® Na, and AClyn® Zn) were used as nucleating additives, and their effect on crystallization of poly(ethylene terephthalate) (PET) was investigated by using differential scanning calorimetry (DSC). The results showed that the crystallization rate of PET is accelerated by both ionomers, and the ionomer co…
Diamond-like carbon (DLC) films were prepared with mass-selected C+, CH2+, CH3+, and CH4+ ions, and the dependence of film microstructures and properties on ion species was investigated with micro-Raman spectroscopy, optical band gap measurement and atomic force microscopy (AFM). The results indicate that highly sp3 b…
Impedance spectra of Co-doped NASICON polycrystalline samples (x = 2.0) were measured in the frequency range 0.5 MHz–1.2 GHz and analyzed in terms of the conductivity dispersion. The dispersion of bulk electrical conductivity obeys the power law frequency dependence σ(ω) = σ0 + Kωn. It is observed from room temperatur…
We investigated the characteristics of Y2O3 films grown on an oxidized Si(111) surface, using x-ray diffraction, Rutherford backscattering spectroscopy, and high-resolution transmission electron microscopy. The films grown on the oxidized Si show drastically improved crystallinity, compared with the film grown on clea…
Carbon nitride films were deposited by pulsed Nd:yttrium–aluminum–garnet laser ablation of graphite with assistance of low energy nitrogen-ion-beam bombardment. The nitrogen to carbon (N/C) atomic ratio, surface morphology, bonding state, and microstructure of the deposited carbon nitride films were characterized by x…
Normally synthetic well defined monodisperse discotic laponite clays are known to form a gel phase at mass concentrations as low as a few percent in distilled water. Hydrosoluble polymer polyethylene oxide was added to this intriguing clay system, it was observed that it either prevents gelation or slows it down extre…
The reaction of [Mn 3 O(2-X-benzoato) 6 L 3 ] (X = Cl, Br; L = pyridine) with 2,2‘-bipyridine in CH 2 Cl 2 leads to the high-yield formation of new mixed-valence tetranuclear Mn I I Mn 3 III complexes of general formulation [Mn 4 O 2 (X-benzoato) 7 (bpy) 2 ] ( 1, X = 2-chloro; 2, X = 2-bromo). The crystal structure of…
Chemisorption and thermal behavior of CO and NO on Pd{110} and its vicinal surface, Pd{320} [Pd(S)[3(110)×(100)]], have been investigated using molecular beam surface scattering (MBSS), temperature programmed desorption (TPD), low energy electron diffraction (LEED), and ultraviolet photoelectron spectroscopy (UPS). CO…
We show that a rich variety of crystalline structures, and a corresponding diversity of the associated phase diagrams, result from the presence in the pair potential of a soft repulsion in addition to a hard core. We use different forms for the soft repulsion, and show that the results are sensitive to the details of…
Abstract This paper describes the structure and electrical performance of PTC/NTC (positive temperature coefficient/negative temperature coefficient) effects and their reproducibility upon healing/cooling cycles. The following three‐component blends were studied: PVDF/UHMWPE/CB, PVDF/XL‐UHMWPE/CB and γ‐irradiated comp…
We consider the application of the Bragg-Pippard (BP) equations for form birefringence to a tilted-columnar biaxial thin film with columns of index n(c) and voids of known index n(v). In such a situation the three forward BP equations that express the principal refractive indices n1, n2, and n3 as functions of n(c), n…
Theoretical calculations based on phenomenology of ferroelectrics have been previously reported for lead zirconium titanate (PZT) system. This paper offers an experimental comparison of the crystal orientation dependence of dielectric properties for PZT thin films grown using reactive RF-sputtering. Highly oriented PZ…
Abstract The properties of polymer blends are largely determined by the morphological structure of the polymer combinations that are involved. In terms of extruder design, this means it is necessary to have models available for estimating the development of the morphology over the length of the screws. Since significa…