Materials Literature
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Magnetoresistance properties of compounds with the same formula La0.7−xGdxCa0.3MnO3+δ (x=0, 0.04) but synthesized by the solid-state reaction method from different starting materials are studied. Nearly stoichiometric compounds are obtained when La(OH)3 is used for sample preparation. However, under the same condition…
The initial attachment reaction of most cultured cell types to polymers is based on a linkage of integrin receptors to serum-derived fibronectin and vitronectin that adsorb onto the polymer surface. Recently isolated corneal epithelial cells have an additional attachment mechanism, known to operate on tissue culture p…
Dielectric measurements at very low temperature indicate that in the multicomponent glass $\mathrm{BaO}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}\ensuremath{-}{\mathrm{SiO}}_{2}$ a phase transition occurs at 5.84 mK. Below that temperature small magnetic fields of the order of $10\ensuremath{\mu}\mathrm{T}$ cause…
Ultraviolet–photon absorption constants were measured for thin CsI, KI, RbI, NaI and CsBr evaporated films, in the 140–200 nm spectral range. The constant measured for CsI is consistent with literature data; the absorption data for the other materials are given here for the first time. The absorption lengths for all m…
In this paper, we report first-principles structural models of surfaces of tetrahedral amorphous carbon $(ta\ensuremath{-}\mathrm{C})$. The topology and defect structure of the amorphous surfaces are analyzed at the atomistic level. We examine the transition of the local bonding environment from the bulk to the surfac…
PbZrO 3 is an antiferroelectric perovskite with TC≈230 °C. We have deposited single phase, perfectly c-axis oriented thin films of PbZrO3 on Si(100) substrates by pulsed laser ablation at 700 °C. The growth conditions (substrate temperature, ambient oxygen pressure, and laser energy density) have been optimized and th…
The random sequential adsorption (RSA) approach was used to analyze adsorption of hard spheres at surfaces precovered with smaller sized particles. Numerical simulations were performed to determine the available surface function φl of larger particles for various particle size ratios λ=al/as and surface concentration…
The energetical ordering and magnetic states of hexagonal and double-hexagonal close-packed (hcp, dhcp) as well as face-centred cubic (fcc) Fe and FeH crystals are studied via spin-polarized ab initio total-energy calculations in the local spin-density approximation and with generalized gradient corrections by means o…
The relation between rheological properties and phase-separated structures of polymer blend solutions is investigated by using the shear microscopy method to obtain insight into the mechanism of steady state formation under shear flow. The time dependence of viscosity and morphology is observed after a stepwise increa…
Using scanning-probe-microscopy techniques, we have measured dielectric relaxation on ultrasmall, mesoscopic, length scales in a glassy polymer (polyvinyl acetate) film near its glass transition. The effective length scale sampled by these techniques is \ensuremath{\sim}50 nm. This is large enough to probe subsurface…
The Peierls phase transition in the quasi-one-dimensional conductor is investigated by means of elastic and inelastic neutron scattering. The effective critical exponent , extracted from the temperature dependence of the integrated intensity from the CDW satellite reflections, is anomalously low, suggesting that the p…
Colossal magnetoresistance has been observed in polycrystalline Gd0.5Sr0.5MnO3 perovskite. Irreversibility and sharp anomalies in the magnetostriction, magnetization, and magnetoresistance isotherms take place at low temperatures (<90 K), which have been attributed to the establishment of a charge-ordered state…
Previous results concerning radiative emission under laser irradiation of silicon nanopowder are reinterpreted in terms of thermal emission. A model is developed that considers the particles in the powder as independent, so under vacuum the only dissipation mechanism is thermal radiation. The supralinear dependence ob…
The strong photoluminescence (PL) of SiOx:H prepared by plasma enhanced chemical vapor deposition has been systematically studied in conjunction with infrared and micro-Raman spectra. We have found that each PL spectrum is comprised of two Gaussian components, a main band and a shoulder. The main band might originate…
Green light emission at room temperature was achieved from nonhydrogenated amorphous silicon–nitrogen (a-SiN) thin films. The films were deposited by cosputtering a silicon target covered with metallic erbium platelets in an Ar+N2 atmosphere. According to the deposition conditions, the nitrogen concentration [N] reach…
The stability of large carbon tori is examined within the elasticity theory. Tori of diameter larger than 200 nm obtained by bending a single-wall nanotube and connecting the two ends together are proved to be stable. Molecular mechanics is used for optimizing the structure of a small polygonal torus $({\mathrm{C}}_{1…
Clinical usage of bioprosthetic heart valves (BPHVs) fabricated from glutaraldehyde-pretreated porcine aortic valves is restricted due to calcification-related failure. We previously reported a highly efficacious ethanol pretreatment of BPHVs for the prevention of cuspal calcification. The aim of the present study is…
Transmission spectra of monodispersed particles exhibit pronounced resonance features from which particle properties can be deduced. ZnS powders were used as model materials since they can be synthesized by homogeneous precipitation with a narrow size distribution. The optical extinction spectra can be simulated using…
Conductivity measurements from 300 to 1200 K of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ thin films, with doping from $x=0$ to $x=1,$ show that the entire doping range fits the adiabatic small polaron model $\ensuremath{\sigma}=(A/T)\mathrm{exp}(\ensuremath{-}{E}_{a}/kT).$ Furthermore the…
Molecular simulations show that the structural transformations which occur in silica glass under high pressure do not require thermal activation, and arise from localized mechanical instabilities associated with disappearances of local minima on the potential energy surface. This result leads to the prediction that th…