Materials Literature
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The direct extrusion foaming process of low-density polypropylene (PP) in a typical single-screw extruder is researched. Effects of five variables on the volume expansion behavior and cellular morphologies are investigated. They are three kinds of polypropylene with different melt flow rates (MFRs), two kinds of chemi…
Compressive properties and failure analysis of unidirectional and plain weave S2-glass/vinylester composites under high strain rate (HSR) loading have been investigated using the Split Hopkinson Pressure Bar (SHPB) technique. A systematic experimental approach has been adopted in this work to identify the damage progr…
The generation of nanosized features via the bottom-up organization of individual atoms and molecules represents one of the most rapidly emerging fields in modern science and technology. In order to gain general and modular access to nanostructures, a construction kit consisting of molecular building blocks with defin…
Rigid polyurethane foams are used as thermal or vibration insulators and energy absorption material, and are often molded directly in place, where a smooth, thin skin forms between the mold and the cellular structure. Density gradients and the presence of a skin are known to affect the mechanical properties of the foa…
Abstract Polymer blends based on polyolefins are of a great interest owing to their broad spectrum of properties and practical applications. However, because of poor compatibilities of components, most of these systems generally exhibit high interfacial tension, a low degree of dispersion and poor mechanical propertie…
Abstract Solvothermal Synthesis and Crystal Structure Determination of AgBiI 4 and Ag 3 BiI 6 AgBiI 4 and Ag 3 BiI 6 were synthesized by solvothermal reaction from AgI and BiI 3 in diluted HI‐solution (20 %) at a temperature of 160 °C. The greyish‐black crystals grow as octahedra (AgBiI 4 ) or hexagonal/trigonal plate…
We study one- and two-dimensional transmission of electromagnetic waves through a finite slab of a dielectric material with negative refraction. In the case when the dielectric slab possesses an intensitydependent nonlinear response, we observe the nonlinearity-induced wave transmission through an opaque slab accompan…
A new twist: Structural twisting by about 32° between the semiquinoneiminecopper(II) entities in 2 caused by weak Cu–S interaction results in a different spin arrangement (↑,↓,↑) than for planar 1 (↑,↑,↓). Most revealingly, 2 has an EPR spectrum typical for a radical whereas 1 displays a signal for a CuII center. Oxid…
Historically, each of the three macromolecular architectural classes, i.e. (I) linear, (II) crosslinked, and (III) branched, has spawned rich polymer science. These architectural discoveries have been characterized by the emergence of new syntheses, structures, phenomena, properties, and products that have dramaticall…
Blocking out aggregation: Triblock copolymers consisting of a central β-sheet polypeptide block with the repeating [(AlaGly)3GluGly]n sequence and poly(ethylene glycol) (PEG) of Mn=750 g mol−1 were prepared and the assembly properties in the solid state were investigated. Attachment of PEG prevented the macroscopic ag…
We report diffusion Monte Carlo (DMC) calculations on MgO in the rock-salt and CsCl structures. The calculations are based on Hartree-Fock pseudopotentials, with the single-particle orbitals entering the correlated wave function being represented by a systematically convergeable cubic-spline basis. Systematic tests ar…
In this study, three-layer particleboards are produced from a mixture of sunflower stalks (Helianthus annuus L.) and poplar wood (Populus alba L.) at certain ratios utilizing urea-formaldehyde (UF) adhesives. Panels with a density of 0.7 g/cm 3 are manufactured with the ratios of 25, 50, and 75 percent particles from…
Cell-tracking experiments by MRI are possible with a novel class of Tb and Eu paramagnetic imaging agents, with which contrast is generated upon irradiation at a specific frequency (see picture). Middle: A) unlabeled; B) Tb-labeled; C) Eu-labeled; D) Tb- and Eu-labeled cells. Left: irradiation at ±180 kHz (Tb-agent-sp…
The state of the art ab initio calculations of quantum mirages,the spin-polarization of surface-state electrons and the exchange interaction between magnetic adatoms in Cu and Co corrals on Cu(111) are presented. We find that the spin-polarization of the surface-state electrons caused by magnetic adatoms can be projec…
Certain equations with integral constraints have as solutions time-periodic pulses of a field-like unknown while a current-like unknown oscillates periodically with time. A general asymptotic theory of this phenomenon, the generalized Gunn effect, has been found recently. Here we extend this theory to the case of nonl…
Rubber friction on wet rough substrates at low velocities is typically 20-30% smaller than for the corresponding dry surfaces. We show that this cannot be due to hydrodynamics and propose a novel explanation based on a sealing effect exerted by rubber on substrate "pools" filled with water. Water effectively smoothens…
Using time-dependent current-density functional theory, we derive analytically the dynamical exchange-correlation correction to the DC conductance of nanoscale junctions. The correction pertains to the conductance calculated in the zero-frequency limit of time-dependent density-functional theory within the adiabatic l…
Licht am Ende des Tunnels: Funktionalisierte einwandige Kohlenstoffnanoröhren mit kovalent oder nichtkovalent gebundenen positiv oder negativ geladenen Gruppen lagern entgegengesetzt geladene Porphyrin-Derivate an. Werden diese Materialien auf durchsichtige Elektroden aufgebracht (siehe Schema), so erhält man photoche…
Light at the end of the tunnel: Single-wall carbon nanotubes—covalently and noncovalently functionalized with positively and negatively charged groups—associated with porphyrin counterparts are absorbed onto transparent electrodes (see scheme) to yield photochemical devices that exhibit monochromatic power conversion…
Optical disks are read out by focusing a beam of high numerical aperture (NA) through the substrate. Deviations of the thickness from the nominal value result in spherical aberration; tilting the substrate results in coma. Exact analytical expressions for the rms aberration per micrometer thickness mismatch (for spher…