Materials Literature
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The theory for the stability of the nematic phase of parallel cylinders due to Mulder [Phys. Rev. A 35, 3095 (1987)] is generalized to binary mixtures. It is shown that adding cylinders of a different length to a one-component nematic phase of cylinders postpones the nematic–smectic A transition, enhancing the range o…
The model framework - group interaction modelling (GIM), thermal energy, model parameters, discussion - energy levels as states of matter polymer properties below the glass transition - volumetric properties, mechanical properties - viscoelasticity, failure initiation conditions, strain and time dependent mechanical p…
Abstract Polypropylene multifilament yarn samples were irradiated by gamma rays in air. The effect of radiation dose on thermal, structural, and mechanical properties was studied. Melting endotherms and crystallization exotherms gave useful information regarding the structural changes. X‐ray diffraction, infrared spec…
Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy carried out on bulk samples of Er2S3-doped Ge33As12Se55 glasses demonstrate that Er3+ is incorporated in optically active sites in the glass and gives rise to a broad ∼1500–1600 nm 4I13/2→4I15/2 PL spectrum similar to those observed in Er-doped…
Electroluminescent devices were fabricated in SiO2 films containing Ge nanocrystals formed by ion implantation and precipitation during annealing at 900 °C, and the visible room-temperature electroluminescence and photoluminescence spectra were found to be broadly similar. The electroluminescent devices have an onset…
Computer simulations of the two (100) surfaces of cubic SrTi${\mathrm{O}}_{3}$ show that the top layer of the SrO-terminated surface reconstructs to a ferroelectric-monolayer phase while the Ti${\mathrm{O}}_{2}$-terminated surface remains bulklike. This behavior is shown to arise from a delicate crystal-environment se…
Electrical transports in the La 1-x Sr x FeO 3 system (0.05<or=x<or=0.3) was investigated as a function of temperature from 80 K to 350 K by dielectric properties, DC and AC conductivities. Two dielectric relaxation peaks appeared and their relative peak heights were closely related to the amount of Sr. The intensitie…
The phase behavior of a colloidal fluid near a solvent first-order phase transition is investigated. Based on analysis and computer simulation of a Ginzburg-Landau model for the solvent coupled to the colloidal coordinates, two scenarios of phase separation are predicted, induced by wetting of the colloidal surfaces w…
Using molecular dynamics simulations, we study the dynamics of the spreading of liquid drops of chain molecules on a solid substrate. In contrast to previous work with monatomic or diatomic fluids, the radius of the spreading layers increases with time with a power law compatible with the $\sqrt{t}$ behavior observed…
The "instantaneous" normal mode (INM) spectrum for a model soft-sphere system is calculated via molecular-dynamics computer simulation for a variety of temperatures both above and below the observed glass transition temperature. In such spectra, the modes can be classified as either real or imaginary frequency. Result…
The field dependence of the dielectric constant of SrTiO3 is investigated using the capacitance versus bias voltage characteristics of various metal-SrTiO3:Nb Schottky diodes. The relative dielectric constant is shown to decrease one order of magnitude for electric fields ranging from 0.1 to 10 MV/cm. At low fields th…
Photoluminescence spectra were measured on homogeneously doped silicon at temperatures of 90 and 295 K. By using the generalized Planck law for the emission of luminescence by indirect transitions, values for the absorption coefficient as small as ${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{\ensuremath{-}1}$ have been o…
Hydrogen-oxidizing bacterium, Alcaligenes eutrophus autotrophically produces biodegradable plastic material, poly(D-3-hydroxybutyrate), P(3HB), from carbon dioxide, hydrogen, and oxygen. In autotrophic cultivation of the microorganism, it is essential to eliminate possible occurrence of gas explosions from the ferment…
Abstract The design, synthesis, characterization, and understanding of new molecular and macromolecular assemblies with large macroscopic optical nonlinearities represents an active field of research at the interface of modern chemistry, physics, and materials science. Challenges in this area of photonic materials typ…
Shape Memory Alloys (SMA) are characterized by a unique solid-solid phase transition during which significant strains are observable. On reversal of this phase transition, the strains also are almost completely recoverable. When properly constrained, a shape memory alloy is capable of producing large actuation forces.…
Shape memory alloy (SMA) materials such as nitinol have unique properties associated with the shape recovery effect and the material's phase changes that have been used in a variety of actuator and sensing applications. By embedding SMA elements into host composite materials, control or modification of the SMA hybrid…
Calculations on lens systems are often marred by the unjustifiable use of the small-angle approximation. This book describes in detail how the ray and wave pictures of lens behaviour can be combined and developed into a theory capable of dealing with the large angles encountered in real optical systems. A distinct adv…
Article Growth Behaviour and Subgrain Structure of W2B5 / Wachstumsverhalten und Subkorn-Struktur von W2B5 was published on February 1, 1995 in the journal International Journal of Materials Research (volume 86, issue 2).
Abstract Fracture toughness values of phenolphthalein poly(ether ketone) (PEK‐C) at 190°C were determined by two different methods, i.e. the conventional crack growth method and the crack stress whitening zone method, which show consistent results. This indicates that the crack stress whitening zone method can be used…
A new series of optically active compounds have been prepared using 4,4″-terphenyldicarboxylic acid and S-2-alcoxypropanols-1. These are Sm*C, SmA and N* chemically stable - especially with regard to racemization and UV-light compounds with a small PS value, high twisting power and left handedness of helix.