Materials Literature
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A two-dimensional liquid droplet placed on a non-uniformly heated solid surface will move towards the region of colder temperatures if the temperature gradient in the solid surface is large enough. Such behaviour is analysed for a thin viscous droplet using lubrication theory to develop an evolution equation for the s…
Two nonmiscible liquids separated by planar interfaces and undergoing shear flow have been simulated with nonequilibrium molecular dynamics (NEMD) methods. A homogeneous shear scheme was used for imposing shear flow in the system. The homogeneous shear algorithm needs to be combined with a profile-unbiased thermostat…
Abstract Many natural materials have exceptionally high values of the mechanical performance indices described in the previous, companion paper. For beams and plates of a given stiffness or strength, or for a column of a given buckling resistance, woods, palms and bamboo are among the most efficient materials availabl…
Abstract The mechanical properties of natural materials as diverse as wood, muscle, shell and bone are plotted on material-property charts which show the relationships between properties. Performance indices are used to identify the load-bearing applications in which each performs particularly well. By these criteria,…
Neuartige lineare Ketten aus Polyoxometallat‐Einheiten PMnW 11 O 39 , die über Mn‐O‐W‐Brücken verbunden sind (Bild unten), liegen in der Struktur der Titelverbindung 1 vor. Diese Ketten aus Keggin‐Einheiten alternieren mit Schichten der organischen Komponente Bis(ethylendithio)tetrathiafulvalen (ET), 1 verspricht inte…
π‐Stapelwechselwirkungen zwischen ca. 3.4 Å entfernten aromatischen Ligandeneinheiten von L − führen zu schwachen ferromagnetischen Kopplungen im Tetramer [Mn 4 L 4 ](PF 6 ) 4 1 . Da der Hohlraum von L − zu groß für ein einzelnes Mn II ‐Ion ist, bildet sich ein Mn 4 ‐Tetraeder, über dessen Dreiecksflächen jeweils ein…
En route to highly colored chromophores, quaterrylenebis(dicarboximides) 1 were prepared, which can function both as pigments and soluble dyes. The polycycles absorb at very long wavelengths and are remarkably stable. R = H, R′ = C12H25; R = OC6H4-p-tBu, R′ = o,o′-iPr2C6H3.
We describe a new algorithm for simulating complex Markoff-processes. We have used a reaction-cell method in order to simulate arbitrary reactions. It can be used for any kind of RDS on arbitrary topologies, including fractal dimensions or configurations not being related to any spatial geometry. The events within a s…
Abstract Aromatic polyamides and polyimides were synthesized from 4,4′‐diaminotriphenylmethane (DA‐TPM) for studying their solubility, thermal, and mechanical properties. The polymers were found to be soluble in amide solvents and pyridine, and this could be attributed to the practically free rotation of the polymer c…
Abstract Relationships between molecular structure and the degradation mechanism of degradable polymers are of special interest for temporary medical applications. The in vitro degradation study of three aliphatic polymers—poly(trimethylene carbonate) (PTMC), poly(trimethylene carbonate‐ co ‐caprolactone) (PTMC‐PCL),…
The detailed dependence of the residual electrical resistivity on the current direction has been measured at 4.2 K in high-purity aluminium single crystals. All the specimens with the same main surface (110) were cut from one single-crystal rod with the residual resistance ratio of about 50000. The bulk residual resis…
Structural rearrangements of the (111) surface in the system Cr 2 O 3 (111)/Cr(110) as a function of temperature were investigated by means of low-energy electron diffraction (LEED) and electron energy loss spectroscopy (EELS). At room temperature, one observes a simple (1*1) LEED pattern of the clean (111) surface. I…
The diffuse scattering located close to Bragg reflections has been measured on a single grain of the AlPdMn icosahedral phase using elastic neutron scattering. This diffuse scattering is mainly due to phason disorder. The intensity distribution and anisotropic shape can be reproduced in the framework of the elastic th…
A combined chemical and enzymatic procedure has been developed to synthesize macroscopic poly[(R)-(-)-3-hydroxybutyrate] (PHB) granules in vitro. The granules form in a matter of minutes when purified polyhydroxyalkanoate (PHA) synthase from Alcaligenes eutrophus is exposed to synthetically prepared (R)-3-hydroxybutyr…
Optical spectra and their temperature dependence have been investigated for a prototypical double-exchange ferromagnet ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.175$). The optical conductivity spectrum above ${T}_{c}$ is characterized…
The tendency of a polypeptide chain to form alpha-helical or beta-strand secondary structure depends upon local and nonlocal effects. Local effects reflect the intrinsic propensities of the amino acid residues for particular secondary structures, while nonlocal effects reflect the positioning of the individual residue…
N-channel field effect transistors with excellent device characteristics have been fabricated by utilizing C60 as the active element. Measurements on C60 thin films in ultrahigh vacuum show on-off ratios as high as 106 and field effect mobilities up to 0.08 cm2/V s.
The optical properties of ${\mathrm{Mo}}^{3+}$ in phosphate glass have been investigated in the 4.2--300 K temperature range by using steady-state and time-resolved narrow-band laser spectroscopy. Steady-state absorption and emission spectra, emission lifetimes, and time-resolved spectra are presented. Fluorescence fr…
This investigation proposes the development of the selective dissolution process for recycling food packaging and other polymeric wastes. This process takes into account that the specific solvent of a particular polymer which is to be separated, must be a non-solvent for the remaining polymers. Likewise, taking into a…
Detailed techniques for the construction of low (4–300 K) and high (300–700 K) temperature uniaxial stress application devices are described, designed for studying stress-induced effects, including ferroelastic (/ferroelectric) detwinning, induced phase transitions, piezo-optical effects in ferroic crystals under in s…