Materials Literature
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The replacement of the phenyl rings at the 5,5'-positions of a bis(dipyrrinato)zinc complex with mesityl groups transforms the molecule from a very weak emitter that deactivates rapidly after photoexcitation (Phif = 0.006; tau approximately 90 ps) to a highly fluorescent chromophore with a long-lived singlet excited s…
X-ray absorption near-edge spectra and temperature-programmed oxidation and reduction data demonstrate that Au(I) and Au(0) are both present in working MgO-supported gold catalysts for CO oxidation. EXAFS data indicate gold clusters with essentially the same average diameter (about 30 A) in each catalyst sample. Thus,…
This paper reports detailed synthesis and characterization of polymers with functional groups for chemoselective immobilization. Various types of 1,4-diiodo-2,5-dialkoxybenzene monomers containing hydrophobic and hydrophilic groups with chemoselective functional group pairs were synthesized and copolymerized with 1,2-…
Selective solvent crazing is proposed as a novel method for depth profiling and obtaining three-dimensional information by AFM on the microphase morphology in ultrathin polystyrene/poly(methyl methacrylate) (P(S- b -MMA)) diblock copolymer films on silicon substrate. To remove selectively one of the blocks, chain scis…
The evolution of photoluminescence (PL) at room temperature from a-Si:H/SiO2 to nc-Si/SiO2 multilayers was observed through step-by-step post-treatment. It is found that the Si dangling bonds caused by dehydrogenation result in an intensified PL peak at 700 nm. The competition between the role of Si dangling bonds and…
In this article, a ferroelectric capacitor is characterized by an experimental Preisach density (PD), determined by first order reversal curves (FORC) method. It is experimentally shown that this density, defined under the usual Preisach assumptions, does not allow a complete model of the ferroelectric behavior. Consi…
In this work, we address the formation of polarons in hyperbranched polymers and their conduction properties from a theoretical and numerical perspective. As a chemical realization, we consider condensed triarylamine molecules. The topology of the macromolecules follows the concept of regular hyperbranched fractals. T…
Diamonds and carbon nanotubes (CNTs) have extraordinary properties with the potential for vast technological and scientific advancements. However, the syntheses of these super materials have required extreme conditions. Recent synthetic developments surrounding catalytic chemical vapor deposition (CCVD) have contribut…
We present a new class of colossal magnetoresistance materials based on a series of frustrated spinels. The spin glass-like compound Zn0.95Cu0.05Cr2Se4, shows a field-induced transition to a ferromagnetic, which is associated with a highly unusual negative magnetoresistance effect (MR > 80%) in low magnetic field. At…
The sharp and broad electron spin resonance (ESR) signals from nanocomposites of conducting polypyrrole (PPy) with inorganic Na+-montmorillonite (MMT) clay were simultaneously observed. The decomposed linewidths (ΔHP-P) of the sharp and broad ESR peaks of the nanocomposites at room temperature were 0.44 G and 21 G, re…
Actinyls AnO 2 with An = U, Np, and Pu in an expanded porphyrin, alaskaphyrin (AP), are studied by a relativistic density-functional method. The electronic structures of both AnO 2 and AnO 2 AP are investigated by considering all possible low-lying states. To examine the importance of relativity, nonrelativistic calcu…
Abstract Three sets of aliphatic polyester dendrimers based on 2,2‐bis(methylol)propionic acid (bis‐MPA) were synthesized. Two of the sets had benzylidene terminal groups and either a trimethylolpropane or triphenolic core moiety. The last set had acetonide terminal groups and a triphenolic core moiety. Benzylidene‐[G…
Stable multilayer thin films, assembled by a combination of layer-by-layer processing of polyelectrolytes and inorganic quantum dot monolayers prepared using the Langmuir−Schaefer deposition procedure, have been examined. Film formation and structure are confirmed using UV−vis absorption measurements and fluorescence…
This article presents a study performed with a dedicated scanning electron microscope on the electrical property evolution of surfaces of (0001)-oriented sapphire (Al2O3) and (100)-oriented yttria-stabilized zirconia (YSZ) single crystals, during a 1.1 keV electron irradiation at room temperature. The type of charges…
The giant magnetoelectric effect of laminated composites of rare-earth-iron alloys (Terfenol-D) and lead–zirconate–titanate (PZT) is calculated by using the finite element method. Our simulations show that the magnetoelectric response of the laminated Terfenol-D/PZT composites is strongly dependent on interfacial bond…
In this article, we report experimental results on the shift of a beam that propagates through a slab of metamaterial, known to exhibit left-handed properties. A similar experiment with a Teflon sample of similar size is also carried out for comparison. The results show the existence of a frequency band over which the…
We investigated the effects of free space charges on hysteresis-loop measurement of compositionally graded ferroelectrics and found that they are quite likely to be responsible for the “polarization offsets” observed in experiments. Taking into account conduction by those free space charges, or time-dependent space-ch…
Band structures and dielectric functions are calculated using density-functional theory and local-density approximation for three $\ensuremath{\beta}$-cristobalite modifications of ${\mathrm{SiO}}_{2}$ with space-group symmetries $\mathrm{Fd}3m,$ $I4\ifmmode\bar\else\textasciimacron\fi{}2d,$ and ${P2}_{1}3.$ Quasipart…
Damage evolution on the Sm and O sublattices in Sm2Ti2O7 single crystals irradiated with 1 MeV Au2+ ions at 170, 300, and 700 K was studied by Rutherford backscattering spectroscopy and O16(d,p)17O nuclear reaction analysis along the 〈001〉 direction. The damage accumulation behavior at each irradiation temperature ind…
Abstract A series of photosensitive hyperbranched polyimides (HB‐PIs) were prepared through facile end‐group modifications of the fully imidized polymer. A triamine, 1,3,5‐tris(4‐aminophenoxy)benzene, and a dianhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, were condensed with a dropwise addition method…