Materials Literature
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In this letter, the reversible and irreversible polarization contributions in donor-doped Pb(Zr,Ti)O3 are investigated using conventional capacitance–voltage (C–V) and hysteresis measurements. The dependence of the Rayleigh coefficient in the subcoercive regime on the doping concentration is investigated and shown to…
We have examined the atomic structure, composition, and bonding at a nominally undoped 58° [001] tilt grain boundary in SrTiO3 in order to develop an understanding of the control that the grain boundary plane exerts over the bulk properties. Room temperature and in situ heating experiments show that there is a segrega…
We investigate, through first-principles calculations, lattice instabilities induced in diamond by the application of high shear stresses. For shear stresses as low as 95 GPa a lattice instability will occur, leading to graphitelike layered structures. This effect is highly anisotropic. The reversal of the direction o…
We report highly substrate-site selective growth of carbon nanotubes by chemical vapor deposition from precursors of ferrocene and xylene mixtures. The technique allows us to grow well-aligned multiwalled carbon nanotubes preferentially on the SiO2 regions of patterned SiO2/Si substrates prepared by conventional litho…
Theoretical aspects of x-ray standing wave method for investigation of the real structure of crystals are considered in this review paper. Starting from the general approach of the secondary radiation yield from deformed crystals this theory is applied to different concreat cases. Various models of deformed crystals l…
We propose an explanation of anomalies observed in the behavior of deformation hardening of Invars. An extremely strong volume magnetostriction, typical of Invars, results in an enhancement of the exchange contribution to the energy of the dislocation system by about three orders of magnitude with respect to its value…
Diffusing-wave spectroscopy (DWS) was used to follow the sol-gel transition of concentrated colloidal suspensions. We present a new technique based on a sandwich of two scattering cells aimed to overcome the problem of nonergodicity in DWS of solidlike systems. Using this technique we obtain quantitative information a…
Charged closed-cell microporous polypropylene foams are shown to exhibit piezoelectric resonance modes in the dielectric function, coupled with a large anisotropy in the electromechanical and elastic material properties. Strong direct and converse dynamic piezoelectricity with a piezoelectric d33 coefficient of 140 pC…
Tunneling of Bloch electrons through a vacuum barrier introduces new physical effects in comparison with the textbook case of free (plane wave) electrons. For the latter, the exponential decay rate in the vacuum is minimal for electrons with the parallel component of momentum ${\bf k}_\parallel=0$, and the prefactor i…
A theory for longitudinal (T1) and transverse (T2) electron spin coherence times in zincblende semiconductor quantum wells is developed based on a non-perturbative nanostructure model solved in a fourteen-band restricted basis set. Distinctly different dependences of coherence times on mobility, quantization energy, a…
Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $γ$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of…
We have investigated the structural and optical properties of Ga-doped ZnO films grown on GaN templates by plasma-assisted molecular-beam epitaxy. The carrier concentration in Ga-doped ZnO films can be controlled from 1.33×1018/cm3 to 1.13×1020/cm3. Despite high Ga incorporation, the linewidth of (0002) ω-rocking curv…
We consider an equilibrium structure of a monolayer formed by weakly charged polyelectrolyte chains tethered to the oppositely charged interface. The interface is characterized by an immobile charge spatially distributed in a sublayer of finite thickness submerging tethered polyions. The Coulomb attraction of tethered…
The rate of thermal decomposition (190−231 °C) of ethanol on Pd/Al 2 O 3 to yield CH 4, CO, and H 2 has been studied in a tubular reactor at differential conversion and in a Berty reactor. Ethanal is a byproduct that is also present as an intermediate species formed in a dehydrogenation reaction. The presence of H 2 i…
The synthesis, crystal structure, and physical characterization of the coordination compounds [Ni(en) 2 ] 4 [Fe(CN) 5 NO] 2 [Fe(CN) 6 ]·5H 2 O ( 1 ), [Ni(en) 2 ][Fe(CN) 5 NO]·3H 2 O ( 2 ), [Mn(3-MeOsalen)(H 2 O)] 2 [Fe(CN) 5 NO] ( 3 ), and [Mn(5-Brsalen)] 2 [Fe(CN) 5 NO] ( 4 ) are presented. 1 crystallizes in the mono…
Perovskite-based monolithic reactors have been studied for methane catalytic combustion. Monoliths have been prepared by washcoating cordierite honeycomb substrates with lanthanum-stabilized γ-Al 2 O 3, on which LaMnO 3 is dispersed. Scanning electron microscopy analysis showed a homogeneous distribution of LaMnO 3 on…
Complexes K11Na1[As2W18(Mn(H2O))3O66]x27H2O (1) and Na12[As2W18(Co(H2O))3O66]x34H2O (2) have been characterized. 1 crystallizes in the orthorhombic space group Pnma, with a = 30.6484(4) A, b = 14.9946(2) A, and c = 19.17080(10) A (Z = 4), while 2 crystallizes in the monoclinic space group C2/c, with a = 14.124(2) A, b…
Given the diversity and complexity of technologies involved in the surface treatments and coatings sector, it is very difficult to find references in the existing literature that interlink most of them. The work that is presented here is aimed at filling that gap. In view of its length, it has been necessary to divide…
The synthesis, structure, and physical properties of the series of molecular magnets formulated as [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion) are presented. All the compounds are isostructural to the [Ru(bpy)3][ClO4][MnCr(ox)3] member whose struc…
Foaming of thermoplastic polymers is a complex process. Here models are presented that address the viscoelastic character of the thermoplastic melt during the expansion phase of foam development. Each cell is described as consisting of a spherical gas bubble surrounded by a spherical shell of polymer containing dissol…