Materials Literature
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The techniques for seeding of a desired polymorph during crystallisation from solutions are reviewed. The basic information about the type of polymorphism needed to consider seeding strategies is discussed first. The development of seeding strategies is facilitated by certain data on the system. Their relevance as wel…
We report the first theoretical estimate of the nuclear-spin dephasing time T_2 owing to the spin interaction with the two-dimensional electron gas, when the latter is in the integer quantum Hall state, in a two-dimensional heterojunction or quantum well at low temperature and in large applied magnetic field. We estab…
We present a study of resonant vibrational coupling between adsorbates and an elastic substrate at low macroscopic coverages. In the first part of the paper we consider the situation when adsorbates form aggregates with high local coverage. Based upon our previously published theory, we derive formulas describing the…
We propose using short-period superlattices as substrates to control the vibrational relaxation dynamics of adsorbate overlayers. The mass modulation of superlattices creates both band gaps and large spectral enhancements in the phonon density of states. These modifications can dramatically alter the coupling between…
Deposition of low surface energy plasma polymer layers onto microroughened PTFE substrates is found to give rise to high repellency toward polar and nonpolar probe liquids. This behavior has been interpreted in terms of Wenzels theory and the Cassie−Baxter relationship.
We discuss dynamic hydrophobicity from the perspective of the force required to move a water droplet on a surface and argue that the structure of the three-phase contact line is important. We studied the wettability of a series of silicon surfaces that were prepared by photolithography and hydrophobized using silaniza…
Sodium Bismuth Titanate, Na 0.5 Bi 0.5 TiO 3 (NBT), has the perovskite structure, general formula ABO 3 . This is one of a limited number 1 of perovskite compounds were substitution occurs at the A-cation site, the vast majority substituting on the B-site. NBT was first described by Smolenskii and co-workers 2 , and d…
A method for particle sizing using a commercial spectrophotometer is presented, based on a Rayleigh−Gans−Debye treatment of the wavelength dependence of turbidity. The finite acceptance angle of the spectrophotometer has been taken into account and shown to be potentially advantageous. The method has been used to moni…
The order−disorder and order−order transitions (ODT and OOT) of a series of mixtures of a compositionally asymmetric polystyrene- block -polyisoprene- block -polystyrene copolymer (SIS) ( f PS = 0.131) and low molecular weight PS homopolymers with different molecular weights have been investigated by using transmissio…
The sulphuric acid used for the preparation of the Fricke dosimeter solution may contain trace impurities that can affect the yield of ferric ions. Two methods, pre-irradiation or oxidation with hydrogen peroxide, have been proposed to reduce the influence of these impurities. Fricke users sometimes omit this treatmen…
The catalytically active form of monofunctional yeast orotidine-5'-phosphate decarboxylase was a dimer (E(2)). The dimer equilibrium dissociation constant was 0.25 microM in 0.01 M MOPS Na(+) at pH 7.2. The bimolecular rate constant for dimer formation was 1.56 microM(-1) s(-1). The dimeric form of the enzyme was stab…
Recent progress in the synthesis of bulk quantities of long WS 2 nanotubes has allowed them to be considered as potential candidates in various applications, specifically in nanotechnology. In order to evaluate their efficacy in such applications and to obtain a better insight into their growth mechanism, morphologica…
A series of new diazamesocyclic ligands based on a diazamesocycle, 1,5-diazacyclooctane (DACO), functionalized by additional donor groups--1,5-bis(N-1-methylimidazol-2-ylmethyl)-1,5- diazacyclooctane (L1), 1-(2-hydroxybenzyl)-1,5-diazacyclooctane (HL2), 1,5-bis(2-hydroxybenzyl)-1,5-diazacyclooctane (H2L3), and 1-(N-1-…
An AB 2 type monomer, an isomeric mixture of 3,5-bis(4-aminophenoxy)diphenyl ether-3‘,4‘-dicarboxylic acid monomethyl ester ( 6 ), was synthesized starting from 3,5-dimethoxyphenol. A hyperbranched polyamic acid methyl ester precursor was prepared from self-polycondensation of the AB 2 type monomer in the presence of…
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionNucleation and Growth of Lead Sulfide Nano- and Microcrystallites in Supramolecular Polymer Assemblies.Ashim K. Dutta, Thaotrang Ho, Liqin Zhang, and Pieter StroeveCite this: Chem. Mater. 2000, 12, 10, 3236Publication Date (…
X-ray diffraction studies on poly(ferrocenylenedimethylsilylene), PFDMS, indicate a 3D crystalline phase with monoclinic packing of the macromolecules with possible unit cell parameters a = 13.29 Å, b = 6.01 Å, c = 13.9 Å, and γ = 93.6° . There are two main chains with four monomer units per unit cell, X-ray crystal d…
A series of poly(3,4-alkylenedioxypyrrole)s are reported as a new class of electronically conducting polymers exhibiting especially low oxidation potentials from ca. −0.6 to −0.4 V vs Fc/Fc + (equivalent to −0.15 to +0.05 V vs SCE) as desired for ambient stability of the doped and conducting states. These polymers exh…
Modulated differential scanning calorimetry was used to probe the thermal behavior of poly(methyl methacrylate) (PMMA) adsorbed onto silica from solution and subsequently dried. Changes in the glass transition were studied as a function of the adsorbed amount and solvent system used to deposit the polymer. The glass t…
An efficient method for calculating the electronic structure of systems that need a very fine sampling of the Brillouin zone is presented. The method is based on the variational optimization of a "single" (i.e. common to all points in the Brillouin zone) basis set for the expansion of the electronic orbitals. Consider…
The semi-classical Lifshitz-Kosevich (LK) description of quantum oscillations is extended to a multiband two-dimensional Fermi liquid with a constant number of electrons. The amplitudes of novel oscillations with combination frequencies, recently predicted and observed experimentally, are analytically derived and comp…