Materials Literature
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Spatial patterning of an aminosilica surface improves the catalytic properties of an organometallic catalyst. The distribution of the sites on the surface creates a more accessible metal center. This accessibility, when combined with the steric constraints imparted by the silica surface, not only allows for improved r…
We examine RCoO 3 (R=La, Ce, Pr, Nd, Sm, Eu, Gd, and Dy) perovskites prepared with the solid-state reaction method by Raman spectroscopy, and report the Raman active phonons in the RCoO 3 perovskites crystallized in cubic symmetry for RCoO 3 (R=La, Ce, Pr and Nd) and orthorhombic symmetry for RCoO 3 (R=Sm, Eu, Gd, and…
This paper provides a study of signal propagation using the finite difference time domain method. It was presented at the 14th International Symposium on High Voltage Engineering in 2005.
The crystal structure of lead zinc niobate (PZN) was studied by very high-resolution neutron powder diffraction using both small (<143 µm) and large (1–2 mm) crystals. No evidence was found for the rhombohedral exterior/cubic interior 'X-phase' structure reported by Xu et al (2004 Appl. Phys. Lett. 84 3975–7). The str…
ZnO crystals were implanted with N+, O+, and Al+, and co-implanted with O+∕N+ and Al+∕N+ ions. Positron annihilation measurements indicate introduction of vacancy clusters upon implantation. In the N+-implanted and Al+∕N+ co-implanted samples, these vacancy clusters are only partially annealed at 800°C, as compared wi…
Abstract Nickel acetate doped poly(methylphenylsilsesquioxane) with and without silicon filler loading was pyrolysed in argon atmosphere between 800 and 1500 °C. The ceramic residues were investigated with specific view of the nanoaggregates formed in pores during the polymer‐to‐ceramic conversion. After pyrolysis at…
Abstract Summary: Two photochromic dithienylethene units were incorporated into one fluorene unit as a monomer and the mole ratio of photochromic unit/repeat unit reached to 2:1 using this monomer. The content of dithienylethene component in the polymer could be improved effectively by polymerization of this monomer,…
The magnetization of a quasisingle-crystalline ${\mathrm{La}}_{0.75}{\mathrm{Sm}}_{0.25}{\mathrm{Mn}}_{2}{\mathrm{Si}}_{2}$ sample was measured under high pressures to $P=1.2\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The compound exhibits four different spontaneous magnetic phase transitions: the ordering of Sm sublatt…
The development status of Ovonic Unified Memory (OUM), a phase-change non-volatile semiconductor memory technology for VLSI stand-alone memory and embedded applications, is discussed. Using 0.18 μm 3 V CMOS, cells from 5F/sup 2/ to 8F/sup 2/ are built in a charge-pump-free 4 Mb development vehicle. Direct overwrite, 1…
The influence of the spontaneous surface modification of titanium by exposure to Ringer's solution at open-circuit conditions on the passive behavior was studied. The electrochemical behavior of Ti was compared in a simple NaCl and in Ringer's physiological solution. Potentiodynamic polarization curves show significan…
Transport measurements of a pressure-induced organic superconductor, ${\ensuremath{\beta}}^{\ensuremath{''}}\text{\ensuremath{-}}{(\mathrm{DODHT})}_{2}\mathrm{P}{\mathrm{F}}_{6}$ $[\mathrm{DODHT}=(1,4\text{\ensuremath{-}}\text{dioxane}\text{\ensuremath{-}}2,3\text{\ensuremath{-}}\text{diyldithio})\text{dihydrotetrathi…
Abstract Summary: The degradation of poly( L ‐lactic acid) (PLLA) into a repolymerizable oligomer was carried out using a clay catalyst, montmorillonite K10 (MK10), with the objective of developing a chemical recycling process. PLLA having an $\overline M _{\rm w}$ of 120 000 was degraded by MK10 in toluene at 100 °C…
The spin-wave and exchange-enhanced spin-density fluctuation contributions to the electrical resistivity, ρ( T ), of weak itinerant-electron ferromagnets are calculated in the absence and presence of the magnetic field, H , employing the two-band (s- and d-band) model and the version of spin-fluctuation theory for d-b…
In this article, we construct a framework for modeling hysteresis and constitutive nonlinearities in ferroelectric compounds based on energy analysis at mesoscopic scales in combination with stochastic homogenization techniques to construct macroscopic models. In the first step of the development, previous analysis is…
Abstract Fiber reinforced concrete (FRC) contains fibers physically mixed with gravel, sand, cement, and water. So far, adequate mechanical performance of FRC has been obtained at high cost and using complex technologies; important here is the geometry and surface characteristics of the polymers. We have modified poly…
A series of polyimides (PIs) were prepared from three biphenyltetracarboxylic dianhydrides (BPDA) isomers, i.e., 3,3′,4,4′-BPDA (s-BPDA), 2,3,3′,4′-BPDA (a-BPDA), and 2,2′',3,3′'-BPDA (iBPDA) with various diamines through the conventional two step process. Polymerization reactivity, solubility, and dynamic mechanical…
We have studied the electron spin resonance (ESR) of single-walled carbon nanotubes (SWNTs) both in their pristine state and after irradiation with fast electrons in order to detect the signal of conduction electrons. No metallic Pauli contribution was observed in the global spin susceptibility, the ESR signal of the…
Adsorption and reactions of NO on clean and CO-precovered Ir(111) were investigated by means of X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HR-EELS), infrared reflection absorption spectroscopy (IRAS), and temperature-programmed desorption (TPD). Two NO adsorption states,…
Dynamic mechanical analysis was performed on a series of the isomeric polyimides (PIs) made from the reaction of s-, a-, and i-BPDA each with 4,4′-ODA, 3,3′-ODA, 1,3,3-APB and 1,4,4-APB. The glass transitions (T g s) moved towards higher temperatures in the order of s-, a-, and i-BPDA for the para diamine-based PIs wh…
Campylobacter jejuni and Campylobacter coli are the main causes of bacterial diarrhea worldwide, and Helicobacter pylori is known to cause duodenal ulcers. In all of these pathogenic organisms, the flagellin proteins are heavily glycosylated with a 2-keto-3-deoxy acid, pseudaminic acid (5,7-diacetamido-3,5,7,9-tetrade…