Materials Literature
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Abstract Significant advances in knowledge of lamellae and their organization in meltcrystallized polymers have stemmed from the ability to examine internal morphologies systematically with the transmission electron microscope. Spherulites form because the first-forming (dominant) lamellae branch repetitively, often a…
The electronic properties of amorphous carbon structures with varying microscopic mass densities, ranging from 2.0 to 3.52 g/${\mathrm{cm}}^{3}$, are analyzed. Using a semiempirical density-functional approach the model structures were generated by molecular dynamics performing a simulated cooling of liquid carbon clu…
The energetics and electronic structure of a series of neutral and charged oxygen and magnesium vacancy defects (F, ${\mathit{F}}^{+}$, ${\mathit{F}}^{2+}$, V, ${\mathit{V}}^{\mathrm{\ensuremath{-}}}$, ${\mathit{V}}^{2\mathrm{\ensuremath{-}}}$, and P centers) in MgO have been computed using the stationary total-energy…
Using a simple three-dimensional lattice copolymer model and Monte Carlo dynamics, we study the collapse and folding of proteinlike heteropolymers. The polymers are 27 monomers long and consist of two monomer types. Although these chains are too long for exhaustive enumeration of all conformations, it is possible to e…
Abstract To improve the wettability and adhesion, graft polymerization of acrylamide (AAm) and glycidyl methacrylate (GMA) was performed onto the surface of ultra‐high modulus polyethylene (UHMPE) fiber pretreated with Ar plasma. Following the plasma treatment and the subsequent exposure to air to introduce peroxides…
A 1 mm x 1 mm nematic liquid-crystal three-terminal device for optical beam forming (focusing/spoiling) is fabricated. A thin-film-resistor network on the device substrate layer is used to control the voltages on the 98 internal lens electrodes by use of only one variable external driver. By using a high-resistance th…
Three different size distributions of Ge quantum dots (≳200, 110, and 60 Å) have been synthesized via the ultrasonic mediated reduction of mixtures of chlorogermanes and organochlorogermanes (or organochlorosilanes) by a colloidal sodium/potassium alloy in heptane, followed by annealing in a sealed pressure vessel at…
The following paper presents the results of a theoretical study that probed the chemistry of water at structural defects on the MgO (001) surface. The computational technique used was periodic Hartree–Fock (PHF) theory with density functional based correlation corrections. The adsorption energies for water adsorbed on…
The electronic properties of shallow band-edge surface traps in nanometer-size CdSe quantum dots are probed using fluorescence-line-narrowing spectroscopy. We find large changes in electron-hole-pair radiative lifetimes and couplings to LO phonons as the temperature is changed from 1.75 to 10 K. We attribute these cha…
Using Brillouin scattering the three independent elastic stiffness constants cij of single-crystal cubic boron nitride have been measured: c11=820, c12=190, and c44=480 GPa. The resulting bulk modulus, 400 GPa, is in reasonable agreement with two independent determinations obtained from x-ray measurements in a diamond…
We present calculated 3 d , 3 p and 3 s resonant photoemission (RPE) spectra in the transition metal (TM) compounds CuO, NiO, CoO, FeO, MnO and TiO 2 at TM 2 p core threshold on the basis of a cluster model. Our model includes the intraatomic multipole electron-electron interactions and the hybridization between trans…
It is demonstrated that the reflective properties and bistability of cholesteric liquid crystals can be controlled by proper surface treatment and dispersed polymers. Dispersing a polymer in the liquid crystal or using a cell with an inhomogeneous surface anchoring creates permanent defects which result in long-term b…
Seaweed has been used since the 1800s in the treatment of wounds. Sorbsan is an alginate dressing designed to absorb large amounts of exudate. Sorbsan is removed by irrigation without causing damage to newly forming tissue. Sorbsan is a relatively painless dressing to remove.
Fine tip structures are required for many applications in different technologies, for example in scanning probe microscopy or vacuum microelectronic devices. Tips can be produced with nanometre precision by the electron-beam-induced deposition technique. The deposition process, however, is still not really understood.…
40π‐Elektronen und zehn Pyrrol‐Einheiten enthält der Makrocyclus 1 , das bisher größte expandierte Porphyrin. Das Tetrahydrochlorid von 1 wurde in Lösung und im Festkörper charakterisiert; nach diesen Untersuchungen liegt der Makrocyclus als Enantiomerenpaar vor, was auf einer Verdrillung des Ringsystems beruht. magni…
ZnO and ZnO:Li films (1-3 mu m thickness) were deposited on a soda lime glass substrate by a spray pyrolysis technique using ZnCl 2 and LiCl as starting materials. Physical properties of these films were studied as a function of substrate temperature T s and lithium concentration. The best ZnO film was obtained for T…
Some empirically founded expressions are established that aim to describe the backscattering coefficient and the energy distributions of electrons backscattered from a bulk solid target (atomic number Z>or=4) within the incident energy region 0.5<or=E 0 <or=100 keV, and for any incidence angle 0<or= Theta <or=60 degre…
1.3 μm to visible upconversion is observed in a BaCl2:Dy,Er phosphor system. Yellow fluorescence is visible under 1.3 μm laser diode (5 mW) irradiation. Radiative transitions from the 4S3/2 and 4F9/2 levels to the ground level 4I15/2 of the Er3+ ions cause fluorescence lines at 550 and 670 nm, respectively. This indic…
The dynamic conductivity has been measured in ${\mathrm{K}}_{0.3}$${\mathrm{MnO}}_{3}$ single crystals in the conducting phase (above 180 K), for the first time over a broad frequency range 1-${10}^{5}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, using a combination of different spectroscopic techniques. Together with…
It is demonstrated that a surface energy anisotropy (anchoring) defines the growth pattern of the field-induced transition in a smectic-$A$ liquid crystal (Sm-$A$). The stable domain phase nucleates as rounded domains but expands as stripes. The change in growth pattern is accounted for a large anchoring strength ${W}…