Materials Literature
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Modularly invariant equations of motion are derived that generate the isothermal–isobaric ensemble as their phase space averages. Isotropic volume fluctuations and fully flexible simulation cells as well as a hybrid scheme that naturally combines the two motions are considered. The resulting methods are tested on two…
The CCP4 (Collaborative Computational Project, number 4) program suite is a collection of programs and associated data and subroutine libraries which can be used for macromolecular structure determination by X-ray crystallography. The suite is designed to be flexible, allowing users a number of methods of achieving th…
Processes leading to the growth of intrinsic insulators (oxides, sulfides, and fluorides) on the surfaces of semiconductors of the III-V, II-VI, and IV-VI groups as well as their solid solutions are analysed with the aid of classical thermodynamics. Their phase compositions, found from the equilibrium phase diagram, a…
We determined the structures of Acanthamoeba profilin I and profilin II by x-ray crystallography at resolutions of 2.0 and 2.8 A, respectively. The polypeptide folds and the actin-binding surfaces of the amoeba profilins are very similar to those of bovine and human profilins. The electrostatic potential surfaces of t…
Proper treatment of long-range Coulombic forces presents a major obstacle to providing realistic molecular dynamics simulations of macromolecules. Traditional approximations made to lessen computational cost ultimately lead to unrealistic behavior. The particle mesh Ewald method accommodates long-range Coulombic force…
The time-resolved photoluminescence of semiconductor nanocrystals was obtained as a function of laser excitation intensity at a low temperature. Exciton and biexciton recombination processes were clearly identified. At laser intensities lower than 3.3×105 W/cm2, only exciton recombination with a lifetime of 4 ns was o…
Frozen-in trans and gauche conformational disorder of symmetrical difluorotetra-chloroethane (DFTCE) produces the tendency of this plastic crystal to form an orientational glassy state on cooling below T g =86 K. To throw light upon the freezing mechanism in DFTCE neutron diffraction and Brillouin scattering as well a…
The electronic structure has been calculated for large approximant crystals (up to 51752 atoms in the periodically repeated cell) to icosahedral AlCuLi quasicrystals. The results show that a deep structure-induced pseudogap at the Fermi energy is a generic property of the quasicrystal and its crystalline approximants.…
A method for determining the infrared dielectric constant function of an isotropic material from measurement of the reflectance from powdered samples has been implemented. The method is based on an expression for the average dielectric constant of a heterogeneous system, which shows percolation features. The results o…
Diamond was deposited on substrates pre-etched with diamond powder using either a microwave plasma chemical vapor deposition method or a hot-filament-assisted chemical vapor deposition method. Density of residual diamond dust (i.e., number of diamond particles per unit area on the surface of a substrate) on the pre-et…
Dynamic dielectric and mechanical responses in the splitting region of PnBMA are analysed with the help of two Havriliak-Negami-function fits. The alpha and beta processes in the Arrhenius diagram are parallel to each other over a wide temperature range, and do not merge.
For the first time the surface structure of an icosahedral quasicrystal could be resolved in direct space by scanning tunneling microscopy. The surface was found to form terraces with their normals being parallel to a fivefold axis. On the terraces fivefold stars and pentagonal holes were observed. Both the step heigh…
Dc magnetron sputtered Ni-Mn and Ni-Mn-Cr films are demonstrated to exhibit strong and thermally stable antiferromagnetism, as well as high corrosion resistance. For a 25.2 nm thick 53.3 Ni-46.7 Mn (in atomic percent) film deposited on top of a 28.5 nm thick 81 Ni-19 Fe film, a unidirectional anisotropy field (HUA) of…
This review presents the state of the art of the study of germanium-related colour centres in silica glass and silica-based fibres. Most attention is concentrated on the dominant colour centres such as the Ge-related oxygen-deficient centres and paramagnetic Ge(n) centres, all of them having ultraviolet absorption ban…
The crystal structure of the complex between ribonuclease A and d(ApTpApApG) has been solved by x-ray crystallography using the molecular replacement method. The model includes, besides the enzyme, the d(ApTpApA) 5'-segment (A1T2A3A4) and 68 solvent molecules. The R-factor for the strongest 87% of the measured data th…
The atomic-scale dynamics of the glass-to-liquid transition are, in general, poorly understood in inorganic materials. Here, two-dimensional magic angle spinning nuclear magnetic resonance spectra collected just above the glass transition of K(2)Si(4)O(9) at temperatures as high as 583 degrees C are presented. Rates o…
The selective catalytic reduction reaction of nitric oxide bv ammonia over vanadia-titania catalysts is one of the methods of removing NOx pollution. In the present study, it has been possible to identify the reaction mechanism and the nature of the active sites in these catalysts by combining transient or steady-stat…
A simple technique is described here that produces aligned arrays of carbon nanotubes. The alignment method is based on cutting thin slices (50 to 200 nanometers) of a nanotube-polymer composite. With this parallel and well-separated configuration of nanotubes it should be possible to measure individual tube propertie…
Abstract A comprehensive non-LTE analysis of Na I lines was performed in order to investigate the photospheric abundance of sodium in typical bright A–F supergiants. Along with the strongest subordinate line, Na I λ8195, newly observed for this study, which enabled us to determine the Na abundance of A supergiants for…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…