Materials Literature
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This work investigates charge redistribution in a series of Ni-Cu alloys using x-ray photoemission spectroscopy (XPS) and Ni/Cu ${L}_{3,2}$- and $K$-edge x-ray-absorption near-edge structure (XANES). XPS results show that the constituent $d$ bands are well separated and shifted to a slightly higher binding energy upon…
Electronic structures of ${\mathrm{LaCoO}}_{3}$ and ${\mathrm{SrCoO}}_{3}$ cluster models near the Fermi level were investigated from ab initio molecular-orbital calculations using the Hartree-Fock approximation, the single-excitation configuration-interaction approximation, and local density approximations in order t…
This work presents a study of the formal structure of the theory of finite–strain polar elasticity and thermoelasticity with special attention to the construction of canonical balance laws that concern the whole system under study and not only each separate degree of freedom. These are the balance of energy and so–cal…
We have investigated the effects of isotopic composition on the band gap of CuCl on a series of samples made out of the stable isotopes ${}^{63}\mathrm{Cu}$, ${}^{65}\mathrm{Cu}$, ${}^{35}\mathrm{Cl}$, and ${}^{37}\mathrm{Cl}$. Besides specimens containing elements with the natural abundances, we have measured samples…
We have studied the elastic and structural properties of ZnO by means of accurate first-principles total energy calculations using the full potential linear muffin tin orbital method. The calculations are based on the density functional theory and we have used the local density Hedin–Lundqvist parametrization and the…
Boron-doped Si nanocrystals as small as 3.5 nm were prepared and their photoluminescence (PL) properties were studied. The PL properties were found to be very sensitive to the B concentration. For the sample without B doping the temperature-dependent shift of the PL peak was almost the same as that of the bulk band ga…
Structural and thermodynamic properties of cubic boron nitride (c-BN) under pressure and for varying temperature are studied by molecular-dynamics (MD) simulation with the use of a well-tested Tersoff potential. Various physical quantities including the thermal expansion coefficient and heat capacity are predicted. Ou…
A new type of solid support for HPLC separation of nucleotides, oligonucleotides, N-protected amino acids, and perfluorinated biphenyls is revealed in the form of two distinct calix[4]pyrrole-modified silica gels (below).
Infrared spectra of hydrogenated lightly doped Czochralski silicon show absorption due to (a) modes of ${\mathrm{O}}_{i}\ensuremath{-}{\mathrm{H}}_{2}$ centers (binding energy 0.26 eV), and (b) a mode labeled ${\ensuremath{\nu}}_{3\mathrm{HH}}$ at $3618{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ due to ${\mathrm{H}}_{2}…
The atomic structure of ordered domains in Ba(Mg1/3Nb2/3)O3 and La-doped and undoped Pb(Mg1/3Nb2/3)O3 is studied by high-resolution Z-contrast imaging. The ordered domain structure in both doped and undoped Pb(Mg1/3Nb2/3)O3 is determined to be in agreement with the charge balanced random-layer model and inconsistent w…
A molecular dynamics simulation of water confined in a silica pore is performed in order to compare it with recent experimental results on water confined in porous Vycor glass at room temperature. A cylindrical pore of 40 Å is created inside a vitreous SiO2 cell, obtained by computer simulation. The resulting cavity o…
Collagenous matrices with entrapped anionic polypeptides can mimic biological processes of mineral deposition by controlling the crystallization of calcium carbonate polymorphs. The concentration and structure of the polypeptides and the collagenous environment play major roles in controlling polymorphism. Random and…
We spatially isolate and detect the luminescence from individual porous Si nanoparticles at room temperature. Our experiments show a variety of phenomena not previously observed in the emission from porous Si including a distribution of emission wavelengths, resolved vibronic structure, luminescence intermittency, and…
X-ray diffraction showed that the volume fraction of 90° domains in tetragonal Pb(Zr,Ti)O3 thin films could be substantially reduced by either hot dc poling or by a bipolar pulsed-field process. In both cases, the (001) Bragg peak increased and the (100) peak decreased. However, ferroelectric hysteresis loops look qui…
Fatigue of Pb(Zr0.53Ti0.47)O3 ferroelectric thin films has been studied with several novel electrode modifications. Doped amorphous silicon is used as a gating layer between the ferroelectric and metal electrode to regulate the type of charge carrier injection during switching of the ferroelectric. This configuration…
The validity of the actinometry method applied to H-atom mole fraction measurements has been analyzed. First, a theoretical approach allowed us to determine boundary conditions for which the validity of actinometry may be critical. For these specific conditions, corresponding to an upper limit of electron temperature…
In this work we develop a unifying and general method for calculating linear viscoelastic properties of multicomponent colloidal mixtures of spherical particles. Using linear response theory based on the many-body Smoluchowski diffusion equation, we derive an exact expression for the zero shear rate shear relaxation f…
We have measured the effect of elastic strain $\ensuremath{\epsilon}$ on the threshold field ${E}_{T}$ for the motion of the higher-temperature charge density wave (CDW) in ${\mathrm{NbSe}}_{3}$. We find that ${E}_{T}$ exhibits a critical behavior, ${E}_{T}\ensuremath{\sim}(1\ensuremath{-}\ensuremath{\epsilon}/{\ensur…
We use simple models and molecular dynamics simulations to determine the effects of polydispersity δ on the equation of state for hard sphere crystals. Experiments show that the osmotic pressure for poly-(methyl methacrylate) (PMMA) spheres with a poly-(12-hydroxy stearic acid) (PHSA) layer with a 5% polydispersity ex…
The $\ensuremath{\sigma}+\ensuremath{\pi}$ electron densities of states of chiral carbon nanotubes are computed with a tight-binding Hamiltonian. Our calculations show that the electronic structures of carbon nanotubes with chiral symmetry are similar to the zigzag and armchair ones. The implications of these results…