Materials Literature
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Create and protect: The cavity shell of a molybdenum/tungsten-storage protein acts as a polytopic host for several types of polyoxotungstate guests, which occur as individual clusters (one shown: yellow W, red O, ribbons protein) that are noncovalently or weakly bonded to the host. The formation of the guests is templ…
We present a mechanism of high-temperature sublimation of carbon nanotubes that does not destroy their ordered makeup even upon significant loss of mass. The atoms depart to the gas phase from the pentagon-heptagon dislocation cores, while the bond disruption is immediately repaired, and the 5|7 seamlessly propagate t…
Abstract Activated layered double hydroxides (LDHs) with high crystallinity, obtained by calcination/rehydration of LDH precursors synthesized by urea decomposition, have higher catalytic activity in acetone self‐condensation and Knoevenagel reactions than less crystalline materials obtained from LDH precursors synthe…
A series of donor-acceptor chromophores was prepared in which the spacer separating 4-dimethylanilino (DMA) donor and C(CN)(2) acceptor moieties is systematically varied. All of the new push-pull systems, except 4 b, are thermally stable molecules. In series a, the DMA rings are directly attached to the central spacer…
The self-assembly of a dehydrophenylalanine containing dipeptide (see figure), yielding highly ordered nanotubular structures, is discussed. The tubes are longer and thinner than previously reported peptide-based tubular structures; they are stable to boiling-water temperatures, different pH conditions, and to a highl…
We study electron and hole injection processes in a forward biased p–n junction electrically induced in a graphene heterostructure with split gates and calculate the ac conductivity associated with the interband and intraband transitions under the conditions of population inversion. It is shown that the net conductivi…
We report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High resolution transmission electron microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases…
We have devised an original laboratory experiment where we investigate the frictional behaviour of a single crystal salt slider over a large number of deformation cycles. Because of its physical properties, salt, a surrogate for natural faults, allows for friction and plastic deformation and pressure solution creep to…
In a rather contradictory situation regarding magnetic data on Co-doped ZnO, we have succeeded in fabricating high-quality single crystalline Zn1-xCoxO (x=0.003-0.07) thin films. This gives us the possibility, for the first time, to examine the it intrinsic magnetic properties of ZnO:Co at a quantitative level and the…
An approach is presented for theoretical calculations of the Debye-Waller factors in x-ray absorption spectra. These factors are represented in terms of the cumulant expansion up to third order. They account respectively for the net thermal expansion $σ^{(1)}(T)$, the mean-square relative displacements $σ^2(T)$, and t…
We have carried out a comparative study of the electronic specific heat and electronic structure of $α$ and $δ$-plutonium using dynmical mean field theory (DMFT). We use the perturbative T-matrix and fluctuating exchange (T-matrix FLEX) as a quantum impurity solver. We considered two different physical pictures of plu…
A series of aluminum ethyls and isopropoxides based upon N,N,O,O-tetradentate Schiff base ligand framework have been prepared. X-ray diffraction analysis and 1 H NMR confirmed that these Schiff base aluminum ethyls and isopropoxides were all monomeric species with a five-coordinated central aluminum in their solid str…
Our first-principles computations show that the ground state of PbTiO$_3$ under hydrostatic pressure transforms discontinuously from $P4mm$ to $R3c$ at 9 GPa. Spontaneous polarization decreases with increasing pressure so that the $R3c$ phase transforms to the centrosymmetric $R\bar{3}c$ phase at around 30 GPa. The fi…
Improvement in film growth technology requires a knowledge of the correlation between microstructural and deposition parameters with electrical properties in hydrogenated microcrystalline Si films. Our study indicates that fractional compositions of the constituent crystallite grains in fully crystallized undoped micr…
The steady state photoconductivity as a function of temperature and light intensity was measured on plasma deposited highly crystalline undoped hydrogenated microcrystalline silicon films possessing different thicknesses and microstructures. Different phototransport behaviors were observed experimentally in films havi…
1. Introduction. 1.1 Conducting Polymers. 1.2 What Are Self-doped Conducting Polymers? 1.3 Types of Self-doped Polymers. 1.4 Doping Mechanism in Self-doped Polymers. 1.5 Effect of Substituents on Properties of Polymer. 1.6 Applications of Self-doped Polymers. References. 2. Self-doped Derivatives of Polyaniline. 2.0 I…
Series Preface. Preface. (Mikhail Baklanov, Martin Green and Karen Maex). 1. Low and Ultralow Dielectric Constant Films Prepared by Plasma-Enhanced Chemical Vapor Deposition. (A. Grill). 2. Spin-On Dielectric Materials. (Geraud Dubois, Willi Volksen and Robert D. Miller). 3.Porosity of Low Dielectric Constant Material…
Oil-water mixtures are ubiquitous in nature and are particularly important in biology and industry. Usually additives are used to prevent the liquid droplets from coalescing. Here, we show that stabilization can also be obtained from electrostatics, because of the well known remarkable properties of water. Preferentia…
The results presented in this work show for the first time that an electric field used to macroscopically align polymer nanofibers can also align polymer chains parallel to the fiber axis. This important result indicates that anisotropic structural properties (mechanical, electrical, etc.) can be induced in polymer na…
First-principles calculations are used to establish that the electronic structure of graphene ribbons with zigzag edges is unstable with respect to magnetic polarization of the edge states. The magnetic interaction between edge states is found to be remarkably long ranged and intimately connected to the electronic str…