Materials Literature
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Abstract The compression creep behavior was monitored at constant temperature and/or relative humidity for two slabstock foams with different hard‐segment content. The tests were performed by applying a constant load (free falling weight) and then monitoring the strain as a function of time over a 3‐h time period. A n…
In soft-mode structural phase transitions the Ginzburg temperature interval in which fluctuations and the interactions between them become important is often observed to be small on the scale of the transition temperature. We consider the size of the Ginzburg interval (GI) in framework and 'cogwheel' structures using…
Abstract A semi crystalline polymer, polyamide, was processed using a new technique. The technique is that of mechanically grinding the material using large inputs of energy at temperatures below the glass‐transition temperature and then later reconstituting the material by applying pressure and holding at a temperatu…
X-ray, M\"ossbauer spectroscopy, and extended x-ray absorption fine structure studies provide an atomic-scale description of the pressure-amorphized ${\mathrm{Ge}}_{4}$. At P>12 GPa a gradual onset of structural disorder accompanied by a molecular-association process is observed. An amorphized state concurring with…
Results from magnetically induced birefringence measurements on pentylcyanobiphenyl in Vycorlike porous glass are reported. We find that the Cotton-Mouton coefficient exhibits sigmoidal behavior with temperature, consistent with changes in the direction and possibly the magnitude of a nonzero tensor order parameter, e…
The photovoltaic behavior and spectral response of n-type (nitrogen-doped) tetrahedral amorphous carbon (ta-C)/p-type crystalline silicon heterojunction photodiodes are reported. Abrupt step junction type characteristics are observed with ta-C films ranging in thickness from 40 to 160 nm. The photovoltage increases an…
Abstract The relaxation behavior of the load in compression and the stress in tension was monitored at constant temperature and/or relatively humidity for a set of four slabstock foams with varying hard‐segment content as well as two of the compression molded plaques of these foams. The majority of the compression rel…
An understanding of heteroepitaxy between perovskite and alkaline earth oxides is developed in terms of ion size and interfacial electrostatics. Interfacial energy minimization at the first atomic layers is the basis for a commensurate, unit-cell stability. This unit-cell stability presents the opportunity to study re…
Atomic force microscopy studies of films deposited from ${\mathrm{C}}^{+}$ ions are reported. For ${\mathit{C}}^{+}$ energies E\ensuremath{\ge}30 eV the films are diamondlike and retain the initial smoothness of the silicon substrate. For E30 eV graphitic films evolve with the surface roughness increasing with decreas…
We have obtained room-temperature electroluminescence (EL) at ∼1.54 μm from Er and O co-doped crystalline p-n Si diodes fabricated by ion implantation, under both forward and reverse bias conditions. Under forward bias, the EL intensity decreases by a factor of ∼15 on going from 110 to 300 K, where a weak peak is stil…
Abstract A new technique to analyze the short‐chain branching distribution (SCBD) in linear lowdensity polyethylene has been developed. The technique referred as crystallization analysis fractionation is based on a stepwise precipitation approach. By monitoring the polymer solution concentration during crystallization…
High-resolution electron microscopy and lithium-7 nuclear magnetic resonance measurements were carried out for a disordered carbon material, prepared by heat treatment of polyphenylene, in which lithium was stored electrochemically. The nuclear magnetic resonance spectrum suggests the existence of Li(2) covalent molec…
When there is a hole in a chemically cross-linked gel, the phase transition from swollen to shrunken phase starts at the free surface of the hole. The growth of the new phase is, however, arrested eventually around the hole with a finite thickness depending on controlling parameters such as temperature. This phenomeno…
We perform Monte Carlo simulations of the pouring of hard ellipsoids into a three-dimensional container. Both oblate and prolate ellipsoids of revolution are examined. Oblate ellipsoids pack so that their symmetry (semi-minor) axes are preferentially aligned with the direction of gravity, and their orientational align…
Abstract The physical properties of unmodified starch, poly(ethylene vinyl alcohol), glycerol, and water mixtures are reported. Thermal and melt‐flow properties of the preprocessed, physically mixed materials were determined along with the tensile properties and morphology of injection‐molded microtensile samples. Mel…
Optical properties of stretched Mylar films [poly(ethylene terephthalate)] were evaluated. Similar birefringence dispersion to liquid crystals over a wide spectral range makes Mylar an attractive phase retardation plate for display applications. Two display modes employing an antiparallel (or π) and a parallel-aligned…
Je Monomer‐Einheit doppelt deprotoniert , als Chelatligand an Cu 2+ gebunden und versteift durch starke Wasserstoffbrückenbindungen des Typs O‐H…O − ‐so liegt Cellulose in Schweizers Reagens vor (Bild rechts), das seit 1857 bekannt und heute Grundlage eines technischen Prozesses zur Membranherstellung ist. Die neuen E…
Far-reaching analogies between μ-oxodiiron(III) complexes of porphycenes and porphyrins with regard to physical, chemical, and structural properties are revealed by investigations of the new metallopor-phycenes 1 (R nPr, tBu). These are obtained by using standard methods for porphyrin chemistry. The Fe-O-Fe angle in…
Single-crystal neutron-diffraction measurements on cobalt tungstate. CoWO 4 , at 15 K and powder measurements in the temperature interval 5-55 K have confirmed that it orders antiferromagnetically below its Neel temperature of 55 K with a magnetic propagation vector ( 1/2 0 0). The chemical unit cell is monoclinic, sp…
We have investigated the formation of textured and epitaxial metallic films on (100) MgO single crystals substrates (lattice constant a=4.21 Å) as a function of deposition temperature during pulsed laser ablation. Platinum (a=3.92 Å) films on MgO with lattice misfit of 7.4% were found to grow epitaxially in the temper…