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We present a study which reveals that the switching speed for the redox reaction of polyaniline is very fast. With a 1200Å film in 2 M sulfuric acid, switching speeds of up to 100 μs with current densities of 100 A/cm 2 are observed with the appropriate compensation for IR loss. The true switching speed is higher stil…
Summary The mobilities of aqueous foams of known texture have been measured in homogeneous bead packs. To correlate the data, a theory developed recently to describe the apparent viscosity of foams in smooth capillaries is extended to account for (1) the capillary pressure imposed by the porous medium and (2) constric…
A review is given of some simplified concepts that will contribute to a better understanding of corrosion fundamentals. The corrosion process involves not only electrochemical reactions but also acid-base reactions, and it is the acid-base nature that diversifies the corrosion phenomena. Anions either catalyze or inhi…
Several techniques are reviewed with which thermal conductivity and phonon scattering can be measured in films of thicknesses ranging from angstroms to millimeters. Recent experimental results are compared critically with previous measurements. It is shown that phonons are very sensitive probes of the structural perfe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransition-metal-catalyzed epoxidationsKarl Anker JoergensenCite this: Chem. Rev. 1989, 89, 3, 431–458Publication Date (Print):May 1, 1989Publication History Published online1 May 2002Published inissue 1 May 1989https://doi.org/10.1021/cr00093a001RIGHTS & PERMISSIONSArticle…
Surface property studies of high-strength and high-modulus carbon fibers indicate that they possess higher surface free energies than previously believed. London dispersion components of the surface free energy were calculated from the increment per methylene group in the free energy of adsorption of n-alkanes at zero…
We have investigated the formation of 〈110〉 oriented fivefold diamond microcrystallites on {001} silicon substrates using high-resolution transmission electron microscopy (HRTEM). The HRTEM micrographs clearly show that fivefold symmetry in diamond microcrystallites results from twinning in {111} planes, in agreement…
The magnetic properties of YFe 2 were investigated using the polarised neutron technique. Flipping ratios were measured for the first five reflections of a powder. The magnetic intensity on the (220) reflection proved that the yttrium site carries a magnetic moment antiparallel to that of the iron site. The results we…
A transmission-electron-microscope technique enables direct visualization of the director field of a liquid-crystal polymer at a resolution of 30 nm. Continuum mechanics is used to describe distortions in the director field produced by a disclination, and the relative bend and splay elastic anisotropy for various poly…
Photoluminescence measurements of the 1.9 eV emission were carried out on high-purity silica glasses subjected to γ-ray irradiation. The time decay of the luminescence, when excited by the 4.8 eV band, indicates that the 4.8 eV absorption and the 1.9 eV luminescence are caused by two different defects, and that an ene…
The surface structure of ${\mathrm{SrTiO}}_{3}$(100) was analyzed at T=120 K by means of low-energy-electron diffraction. The best theory-experiment fit results for a surface containing domains of two different layer terminations. Both of them show a first-layer puckering with oxygen ions being pulled out of the surfa…
As another new high quality nonlinear optical (NLO) crystal of the borate series, lithium triborate LBO has been characterized in our Fujian Institute. This follows theoretical calculations of the second harmonic generation (SHG) coefficients on the basis of the anionic group theory (which has been generalized into a…
The analysis of the electronic properties of the tight-binding Fibonacci Hamiltonian is carried out using dynamical systems techniques. Two classes of Fibonacci sequences are considered, corresponding to the cases when there are two types of building blocks and also when there are three types of building blocks. The r…
In this Letter we report the experimental determination of the eigenvalue spectrum, density of states, and individual eigenfunctions in an acoustic system analogous to a two-dimensional Schr\"odinger equation with a quasiperiodic (Penrose tile) potential. The results show features unique to the quasiperiodic symmetry,…
Using the evanescent-wave-ellipsometry technique, we have studied the orientational wetting behavior of the homologous series of alkyl cyanobiphenyl liquid crystals (nCB, n=5 to 9) on a glass coated with silane surfactant molecules. The results show complete wetting for 6CB to 9CB and partial wetting for 5CB. They com…
Abstract Electrochemical polarization measurements have been used to examine the corrosion of carbon steel by aqueous CO2 at partial pressures from 0 to 1.4 MPa in rotating disk and static electrode cells at 25°C. A detailed corrosion mechanism was derived which consisted of four redox reactions under varying types of…
In the isotropic-to-lamellar transition, nonlinear fluctuation terms lower the transition temperature ${\ensuremath{\tau}}_{c}$ and drive the transition first order. Here we show that steady shear, by suppressing the fluctuations, raises ${\ensuremath{\tau}}_{c}$; in a certain temperature range the lamellar phase can…
Quasistatic and kinetic studies of the infrared CO stretch bands of carbonmonoxymyoglobin show that proteins and glasses share essential characteristics, in particular metastability below a transition temperature and relaxation processes that are nonexponential in time and non-Arrhenius in temperature.
Neutron reflectivity from annealed thin films of the poly(styrene-b-deuterated methylmethacrylate), P(S-b-D-MMA), reveals the formation of a multilayered morphology parallel to the film surface. This multilayer forms so that PS locates, preferentially, at the air/copolymer and D-PMMA at the substrate/copolymer interfa…
The effects of ion bombardment on the morphology of compact lead films of under 100 nm thickness were investigated by spectroscopic ellipsometry, Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). In contrast to the expected uniform removal of the surface by ion bombardment, on which the determ…