Materials Literature
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We employ molecular dynamics (MD) simulations to study the structure of vitreous boron oxide. Although six-membered boroxol rings have been observed at fractions over 60% by various experimental techniques, simulation methods have not produced similar results. We adapt the polarization model, which includes many body…
In this study, α-Fe/Nd2Fe14B nanocomposite magnets with strong crystallographic texture were prepared by controlled melt spinning. For a relatively low wheel speed of 10 m/s, the c-axis texture of the Nd2Fe14B crystals is predominantly perpendicular to the plane of the ribbon, but it switches to parallel to the ribbon…
Switching behavior of 90° domains in epitaxial Pb(Zr0.32Ti0.68)O3 thin films under applied bias voltage was investigated in situ using synchrotron x-ray diffraction, and contribution of the switching to ferroelectric P–E hysteresis curve could be estimated. The electric field in the region illuminated by x ray was mad…
A method is reported for controlling the diameter of single-walled carbon nanotubes (SWCNTs) during the electric-arc-discharge process. Using argon as inert atmosphere provides smaller diameters as compared with those when pure helium is used. Varying the gas mixture from argon to helium changes the diameter distribut…
In an effort to understand the anomalous behavior of the viscosity of liquid beryllium fluoride relative to other liquids in the strong/fragile classification we have carried out ion dynamics computer simulations of BeF2 over a temperature range which overlaps with the experimental viscosity data. Using the simple rig…
We studied the morphological evolution during spinodal phase separation and subsequent coarsening in systems with a strong dependence of elastic constants on the composition. An efficient numerical method is developed for solving the two-dimensional inhomogeneous elastic equilibrium equations by using the conjugate gr…
The magnetization of Ga1−xMnxN (x<0.1) crystals was measured as a function of the magnetic field and temperature. Paramagnetic behavior typical of spin S=5/2 expected for Mn2+ (d5) magnetic centers was observed in the temperature range of 2 K<T<300 K. On the other hand, antiferromagnetic coupling…
The dynamics of oligomer desorption from surfaces have been studied by measuring the desorption kinetics of a set of n-alkanes from the surface of single crystalline graphite. Desorption rates were measured using a set of 21 monodispersed n-alkanes (CNH2N+2,5⩽N⩽60) each adsorbed at coverages in the range <0.1 t…
Multilayer "ferromagnet-layered antiferromagnet" (Fe/Cr) structures frustrated due to the roughness of layer interfaces are studied by numerical modeling methods. The "thickness-roughness" phase diagrams for the case of thin ferromagnetic film on the surface of bulk antiferromagnet and for two ferromagnetic layers sep…
Strategies and concepts for the design of THz emitters based on the quantum cascade scheme are analyzed and modeled in terms of a fully three-dimensional Monte Carlo approach; this allows for a proper inclusion of both carrier-carrier and carrier-phonon scattering mechanisms. Starting from the simulation of previously…
We present an atomistic theory of electronic transport through single organic molecules that reproduces the important features of the current-voltage characteristics observed in recent experiments. We trace these features to their origin in the electronic structure of the molecules and their local atomic environment.…
We present trends in the multilayer relaxations of several vicinals of Cu(100) and Cu(111) of varying terrace widths and geometry. The electronic structure calculations are based on density functional theory in the local density approximation with norm-conserving, non-local pseudopotentials in the mixed basis represen…
The hole-doped (p-) manganite La0.7Ca0.3MnO3 and the electron-doped (n-) manganite La0.7Ce0.3MnO3 undergo an insulator-to-metal transition at around 250 K, above which both behave as a polaronic semiconductor. We have fabricated an epitaxial trilayer (La0.7Ca0.3MnO3/SrTiO3/La0.7Ce0.3MnO3), where SrTiO3 is an insulator…
We have investigated the antiferroquadrupolar(AFQ) order in DyB$_2$C$_2$ by resonant x-ray scattering. X-rays with energies near the $L_3$ absorption edge of Dy were employed. Superlattice peaks that correspond to three kinds of propagation vectors of (1 0 0), (1 0 1/2) and (0 0 1/2) were investigated in detail with p…
We report resistivity, thermopower and magnetic susceptibility measurements on the Nb$_4$-cluster compounds Ga$_{1.33}$Nb$_4$X$_{8}$ (X = S, Se), derived from vacancy ordered spinels A$_x$T$_4$X$_8$. The cubic selenide phase is insulating and its resistivity crosses over from $\lnρ \sim T^{-1}$ to $\sim T^{-1/2}$ on c…
The processes of freezing and melting were present at the beginnings of the Earth and continue to dominate the natural and industrial worlds. The solidification of a liquid or the melting of a solid involves a complex interplay of many physical effects. This 2001 book presents in a systematic way the field of continuu…
Thermal elimination reactions on polycarbonates are investigated from both theoretical and experimental points of view, to obtain insight into the microscopic aspects that influence the reaction mechanism and rates. In particular, attention is focused on the influence of the type of substituents in the polymer chain o…
Electropolymerized films of the functionalized pyrrole, pentafluorophenyl-3-(pyrrol-1-yl)propionate (PFP), were reacted with a solution-phase nucleophile, ferrocene ethylamine. This reaction was chosen as a model representative of a postdeposition modification of the polymer membrane's properties. For the first time,…
A large photoinduced anisotropy ratio was observed in the push−pull azo dyes bonded covalently to polyurethane by polarized UV−vis spectroscopy. During irradiation with an Ar + laser, the absorbance perpendicular to the polarization direction of the laser light increases gradually even when the photoisomerization rate…
New derivatives of poly(isothianaphthene methine) have been synthesized by a polycondensation reaction of 1,3-bis( tert -butyldimethylsilyl)isothianaphthene with benzaldehydes in the presence of POCl 3 . In the para position the benzaldehydes possesses a liquid crystalline group, which contains a phenylcyclohexyl, phe…