Materials Literature
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The anisotropic (directional-dependent) properties of contracting tracheal smooth muscle tissue are estimated from a computational model based on the experimental data of length-dependent stiffness. The area changes are obtained at different muscle lengths from experiments in which stimulated muscle undergoes unrestri…
We present molecular dynamics simulations of a chemically realistic model of 1,4-polybutadiene and a freely rotating chain model derived from the first model by neglecting all dihedral potentials. We show that the presence of energy barriers hindering dihedral rotation leads to an intermediate plateau regime in the ta…
Abstract A mathematical model for the controlled degradation of polypropylene is presented in this article. A previous model of this process was extended to predict the whole molecular weight distribution of the modified resin. Probability generating functions were applied to transform the infinite set of mass balance…
We have investigated the transient third-order optical nonlinearity of the solutions of Metal(dmit)2/(mnt)2 salts in acetone by employing femtosecond optical Kerr gate measurement at 830 nm wavelength. An order of enhancement on the second-order hyperpolarizability is found for the above salts with central atoms of Cu…
A novel neutral mixed-valent Cu(I)Cu(II)(2) triangular metallomacrocycle [Cu(3)L(2)(HL)].3CH(3)OH.2H(2)O (1) was assembled by reaction of the tetradentate ligand bis(N-salicylidene-4,4'-diphenylamine), H(2)L, with a copper(II) salt. ESI-MS show peaks only corresponding to the triangular structural species, indicating…
Recent experiments have established that, at least for van der Waals glass formers, volume fluctuations contribute significantly to the slowing down of the dynamics near T(g). Accordingly, we use the Cohen-Grest (CG) free-volume model to analyze dielectric relaxation data for six van der Waals liquids. The CG equation…
The synthesis, characterization, and properties of a highly soluble bifunctional polymer are described in which a tris(bipyridyl)Ru(II) unit acts as dye and triphenylamine units act as charge transport moieties. First a macroligand, a bipyridine carrying two poly(4-bromostyrene) chains, was synthesized by atom transfe…
The Mn–Li ferrite system Li1−0.5xFe1.5x+1Mn1−xO4 (x = 1, 0.8, 0.6, 0.4, 0.2) has been studied by means of X-ray diffraction, Mössbauer spectroscopy and Mn K- and Fe K-edge XANES/EXAFS. All the samples show the spinel-related structure with the lattice constant a gradually decreasing between a = 0.8310 nm (x = 1) and a…
Amorphous poly(diethylsiloxane) (PDES) elastomers undergo a transition to an aligned mesomorphic state when subjected to uniaxial tension. The structural changes associated with this transition and the kinetics of its formation have been investigated by in-situ synchrotron wide-angle and small-angle X-ray scattering.…
The understanding of the phase behavior of dendritic polymers, i.e., hyperbranched polymers and dendrimers, is still in its infancy. No systematic thermodynamic investigations on the phase behavior of dendritic polymer solutions have been reported so far. Therefore, this experimental study focuses on the low- and high…
We report x-ray scattering studies of nanoscale structural correlations in the paramagnetic phases of the perovskite manganites ${\mathrm{La}}_{0.75}({\mathrm{Ca}}_{0.45}{\mathrm{Sr}}_{0.55}{)}_{0.25}{\mathrm{MnO}}_{3},$ ${\mathrm{La}}_{0.625}{\mathrm{Sr}}_{0.375}{\mathrm{MnO}}_{3},$ and ${\mathrm{Nd}}_{0.45}{\mathrm{…
The CO + NO reaction on Pd(111) has been studied at pressures up to 240 mbar using in situ polarization modulation infrared reflection−absorption spectroscopy (PM-IRAS), which simultaneously provides information on the in situ adsorption behavior as well as the reaction kinetics via gas-phase infrared absorption. Unde…
Abstract Montomorillonite was organically modified with three different swelling agents: n ‐dodecylamine, 12‐aminolauric acid, and 1,12‐diaminodecane. These organoclays and polyamide 6 (PA6) were blended in a formic acid solution. X‐ray diffraction analysis showed that the clay still retained its layer structure in th…
Tetraantennary peptides [glycine(n)-NHCH(2)](4)C can form stable noncovalent structures by self-assembly through intermolecular hydrogen bonding. The oligopeptide chains assemble as polyglycine II to yield submicron-sized, flat, one-molecule-thick sheets. Attachment of alpha-N-acetylneuraminic acid (Neu5Acalpha) to th…
A new copolymer, constituted by the regular alternation of a fluorene derivative with a 1,1-dioxothiophene moiety, has been synthesised via Suzuki coupling. The molecular, thermal, structural, and photophysical characterisations have been performed. The material showed two dimensional order, enhanced by annealing; mol…
It is demonstrated that attenuated total reflection infrared (ATR-IR) spectroscopy can be effectively used for in situ investigation of supported catalyst−liquid interfaces. Thin (ca. 10 μm) films of a 5 wt % Pt/γ-Al 2 O 3 catalyst were deposited onto the surface of a germanium waveguide. The very small support partic…
We model the process of densification of silica glass using molecular dynamics simulation in order to resolve the current controversy regarding the existence of the first-order phase transition in this material. We propose the picture in which the structural changes start to take place in the pressure window between 3…
Abstract Investigations have been ongoing to learn the rheological and/or mechanical behavior of composite solid propellants based on hydroxyl‐terminated polybutadiene (HTPB). The mechanical properties of these materials are related to the macromolecular structure of the binder as well as to the content and nature of…
A theory of the glass transition of network liquids is developed using self-consistent phonon and liquid state approaches. The dynamical transition and entropy crisis characteristic of random first-order transitions are mapped as a function of the degree of bonding and density. Using a scaling relation for a soft-core…
We report a numerical study of crystallization and melting in bulk statistical homogeneous (random), homogeneous (slightly alternating), and heterogeneous (produced in a batch reaction) copolymers formed by crystallizable monomers and noncrystallizable comonomers. In our dynamic Monte Carlo simulations of lattice chai…