Materials Literature
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Single-crystal variable temperature EPR, optical and polycrystalline magnetic susceptibility studies have been made on a novel six-coordinate Ag(II) complex. Temperature dependent EPR studies on pure single crystals of this compound reveal that dynamic Jahn-Teller distortion operates above 230 K, between 230 K and 120…
Three-dimensional Monte Carlo simulations of flexible and semiflexible polymer brushes at various grafting densities are carried out to study their equilibrium structure and attendant properties by using the bond fluctuation model. Our simulation results of long flexible polymer brushes are, in general, consistent wit…
Bis(alkylcyclopentadienyl)arenes have been prepared by sequential lithiation/alkylation of dibromoarenes with alkylcyclopenta-2-en-1-ones. The resulting dicarbinols were dehydrated with p -toluenesulfonic acid to give the bis(alkylcyclopentadienyl)arene. Poly(alkyl-1,1‘-ferrocenylenearylene)s were prepared by the reac…
Two experimental techniques, forward recoil spectrometry (FRES) and size exclusion chromatography with fluorescence detection (SEC/fluorescence), have been used to monitor independently the extent of reaction between model end-functional polymers at a PS/PMMA interface. Bilayer samples comprising a polystyrene layer c…
A polyester-type waterborne polyurethane (WPU) was synthesized with 2,4-tolylene diisocyanate (TDI), poly-1,4-butylene glycol adipate (PBA), and 2,2-bis-(hydroxylmethyl) propionic acid (DMPA). A series of compression-molded sheets coded as STPU were prepared by mixing thermoplastic starch (TPS) with the desired amount…
We report mesoscale regions with distinctive magnetic properties in epitaxial ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ films which exhibit tunneling-like magnetoresistance across grain boundaries. By using temperature-dependent magnetic force microscopy we observe that the mesoscale region…
18S-RNA was analysed for 17 species from 8 genera of Scenedesmaceae sensu KOMAREK et FOTT (1983) and one strain of Coelastropsis (Coelastraceae) and Coelastrella (Scotiellaceae). According to the results a subfamily Desmodesmoideae was set up, the subgenera Acutodesmus and Scenedesmus were verified and Scenedesmus (Ke…
We study the equilibrium energies of two-dimensional (2D) noncoarsening fluid foams, which consist of bubbles with fixed areas. The equilibrium states correspond to local minima of the total perimeter. We present a theoretical derivation of energy minima; experiments with ferrofluid foams, which can be either highly d…
Nylon 11 coatings filled with nominal 0–15 vol % of nanosized silica or carbon black were produced using the high velocity oxy-fuel combustion spray process. The scratch and sliding wear resistance, mechanical, and barrier properties of nanocomposite coatings were measured. The effect of powder initial size, filler co…
Surfactant bilayers adsorbed on TS-1 zeolite were used as templates to produce colloidal nanocomposites with a polypyrrole (Ppy) shell. The adsorbed surfactant was cetylpyridinium chloride, and it plays a critical role for attaining both the colloidal stability of the nanocomposites and an enhanced conductivity of the…
A series of eight ${\mathrm{AMnO}}_{3}$ perovskites in which the A-cation sites are occupied by a distribution of 70% trivalent lanthanide and 30% divalent Ca, Sr, or Ba ions has been prepared. These all have a mean A-cation radius of 1.20 \AA{}, but different values of the size variance ${\ensuremath{\sigma}}^{2}.$ A…
Photoinduced processes in zinc porphyrin−C 60 dyad (ZnP−C 60 ) in different organic solvents have been investigated by fluorescence lifetime measurements and pico- and nanosecond time-resolved transient absorption spectroscopies. Irrespective of the solvent polarity, the charge-separated state (ZnP •+ −C 60 •- ) is fo…
Mono- and poly-disperse melts of oligomers (average length 10 monomers) of trans-1,4-polyisoprene are simulated in full atomistic detail. The force-field is developed by means of a mixture of ab initio quantum-chemistry and an automatic generation of empirical parameters. Comparisons to NMR and scattering experiments…
Molecular Dynamics simulations have been performed on the orientationally disordered crystal chloroadamantane: a model system where dynamics are almost completely controlled by rotations. A critical temperature T_c = 225 K as predicted by the Mode Coupling Theory can be clearly determined both in the alpha and beta dy…
In periodic, two-dimensional potentials a classical particle might be expected to escape from any finite region if it has enough energy to escape from a single cell. However, for a class of sinusoidal potentials in which the barriers between neighboring cells can be varied, numerical tridiagonalization of Liouville's…
We have studied the magneto-elastic coupling in the double layered Mn perovskite La$_{1.2}$Sr$_{1.8}$Mn$_2$O$_7$ with an ultrasonic velocity technique. The temperature profile of both the in-plane and out-of-plane longitudinal velocities showed a large stiffening anomaly below the insulating paramagnetic to metallic f…
Oriented MFI membranes made by secondary growth on the surface of α-Al 2 O 3 support disks have been evaluated for the separation of xylene isomers vapors in the temperature range 22−275 °C and feed partial pressures up to ∼0.7−0.9 kPa. It is found that the separation performance of these membranes is directly related…
We have measured the transverse resistance of an intermetallic compound ${\mathrm{Mn}}_{3}\mathrm{GaC}$ in pulsed high magnetic fields up to 25 T. Giant magnetoresistance is observed due to the field-induced magnetic transition from the antiferromagnetic to the intermediate phase at low temperatures. The temperature d…
We report broadening of Raman spectrum and decreasing intensity over a range from 400 to 900 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for sintered polycrystalline ${\mathrm{La}}_{0.75}{\mathrm{Ca}}_{0.25}{\mathrm{MnO}}_{3}$ in the presence of an external magnetic field. The observation of ``structural changes'' when…
This is one of a series of ten papers reporting aspects of the chemistry of cyclic peptides of marine origin. All reported significant results regarding the binding of metal ions. Here the structural complexity of the peptides by forming cylindrical and conical structures, new classes of molecular receptors, was devel…