Materials Literature
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The electrical properties of sisal fiber-low density polyethylene (LDPE) and coir fiber-LDPE composites have been studied. The dielectric constant progressively increases with increase of fiber loading and decreases with increase of frequency in the case of all composites. The dielectric constant of sisal-LDPE composi…
We present a statistical fragmentation study of doubly charged alkali (Li, Na, K) and antimony clusters. The evaporation of one charged trimer is the most dominant decay channel (asymmetric fission) at low excitation energies. For small sodium clusters this was quite early found in molecular dynamical calculations by…
Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths in the range from 514.5 to 1320 nanometers. Numerous Raman peaks were observed and identified with vibrational modes of armchair symme…
We present a kinetic adsorption model for proteins that accounts for the experimentally observed properties of partial reversibility and surface induced conformational change. Particles (proteins) are modeled as disks that adsorb sequentially and without overlap at random positions onto a surface. Following adsorption…
We have measured the temperature dependence of the infrared bandwidth of several lattice phonons and internal vibrons in natural and 32S isotopically pure orthorhombic sulfur crystals, using a high resolution FTIR interferometer. The experimental data were analyzed in terms of anharmonic phonon–phonon coupling process…
Computer simulation is carried out for studying the microphase separation of a two-dimensional diblock copolymer (DBCP) system under directional quenching. By setting the quenching boundary between the stable and the unstable phase, and shifting the boundary with a constant velocity, the time evolution of the domain m…
The recent fabrication of thin-film helicoidal bianisotropic mediums (HBMs) has created an impetus for understanding their electromagnetic response. Using the Oseen transformation, we have derived a 4×4 matrix ordinary differential equation for oblique (i.e. non–axial) propagation in general linear HBMs. A perturbatio…
This work presents an application of recently developed ideas about how to map real polymer systems onto abstract models. In our case the abstract model is the bond fluctuation model with a Monte Carlo dynamics. We study the temperature dependence of chain dimensions and of the self-diffusion behavior in the melt from…
Crystal structure of zinnwaldite 2M(1) was refined in the Cc space group with R equal to 5.8% and R(w) 7.5%. Its octahedral sheet is hetero-octahedral, with octahedra around M1 and M3 having the same mean cation-anion bond length, whereas the third (around M2) has the mean bond significantly shorter. In terms of elect…
The Rouse–Zimm discrete hydrodynamic model is extended to acyclic macromolecules of any topology, and particular attention is devoted to starlike dendrimers and other symmetric cascade structures. As a first approximation, freely rotating models are built for branched structures by means of appropriate choices of topo…
We have mapped out the complete phase diagram of hard spherocylinders as a function of the shape anisotropy L/D. Special computational techniques were required to locate phase transitions in the limit L/D→∞ and in the close-packing limit for L/D→0. The phase boundaries of five different phases were established: the is…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Charge distributions in maleic anhydride (MAH) grafted polyethylene (g-PE)/ethylene - vinyl - acetate (EVA) copolymer laminates have been measured with materials of different composition. All laminates showed interfacial charge, the polarity and the magnitude of which are explained by interfacial polarization. It was…
Clusters with and without cavities are formed in the reaction of [CdCl2(PPh3)2] with PhSeSiMe3. Depending on the organic solvent used, [Cd10Se4(SePh)12(PPh3)4] or [Cd16(SePh)32(PPh3)2] (depicted on the right; the cluster is almost completely covered with phenyl rings) crystallizes. The clusters are composed of fused a…
A markedly different emission behavior is exhibited by the two rhenium complexes 1 and 2. These can be interconverted photochemically; the forward reaction (cyclization to the “closed” form) is triggered by visible light, and the reverse reaction by UV light. Therefore, this is a photoswitchable molecular system in wh…
D3d symmetry characterizes complex 1 (see structure on the right). This circular molecular contains 18 high-spin, antiferromagnetically coupled iron(III) centers. Isolated as the double salt 1 · 6Et4N(NO3) · 15CH3OH · 6Et2O · 24H2O it is the largest cyclic ferric cluster yet reported.
For the development of molecule‐based switching devices , cobalt and manganese complexes of 1,2‐benzoquinone ligands are of great interest. These compounds have electronically labile ground states, which leads to phenomena such as mixed valency, spin crossover, and valence tautomerism. Recently, the electronic behavio…
A 16-amino acid oligopeptide forms a stable beta-sheet structure in water. In physiological solutions it is able to self-assemble to form a macroscopic matrix that stains with Congo red. On raising the temperature of the aqueous solution above 70 degrees C, an abrupt structural transition occurs in the CD spectra from…
Applying a practical density-functional-based perturbation theory, we examine the phase behaviour of a model system interacting via a hard core plus a square-shoulder repulsion. For sufficiently narrow shoulders, the theory predicts coexistence between expanded and condensed isostructural (fcc) crystals, in quantitati…
Studies were performed to develop a sub-100 nm biodegradable colloidal system for the efficient delivery of drugs and diagnostic agents to the lymphatic system. Nanospheres of poly(lactide-co-glycolide) were prepared by interfacial polymer deposition. The nanospheres were coated with block co-polymers in order to modi…