Materials Literature
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The oxygen doping of delafossite compounds MCuO 2+δ allows the production of various networks of spins 1/2 (Cu 2+ ) by the insertion of additional O atoms in the Cu layers that increase the valence of the Cu atoms. For instance, Δ-chains of spins 1/2 can be stabilized in Y CuO 2.5 . In this compound, some glassiness i…
Resonant Raman measurements of \ensuremath{\alpha}-hexathiophene at 33 K have identified over ten vibrational modes that couple to electronic excitations in the single crystal. These excitations at 2.066 eV and 2.068 eV with a width of 2meV have been tentatively identified as bound singlet Frenkel excitons or a triple…
We investigate spreading of phase separated copolymer films, where domain walls and thickness steps influence polymer flow. We show that at early stages of spreading its rate is determined by slow activated flow at terrace steps (i.e., thickness steps). At late stages of spreading, on the other hand, the rate is deter…
Enhanced expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and other endothelial cell adhesion molecules (ECAMs) are associated with the onset and progression of inflammatory bowel disease (IBD). We show in this study that two cytochrome p-450 (CYP450) inhibitors from Citrus paradis (grapefruit), ber…
Lifetimes of triplet-state molecules and triplet quantum yields are important parameters in photobiology as they determine the generation of singlet-oxygen upon irradiation with visible light. Here we report lifetimes of protoporphyrin IX (pp) in vacuo measured in an ion storage ring. We find that after 532 nm photon…
The thermophysical, dielectric and electro-optic properties of polymer-dispersed liquid crystal (PDLC) films made of monodisperse polystyrene (PS) and 4-n-pentyl-4(')-cyanobiphenyl (5CB) are investigated by polarized optical microscopy, differential scanning calorimetry, ac impedance analysis, and forward transmittanc…
We investigate the phase behavior of tetrapods, hard nonconvex bodies formed by four rods connected under tetrahedral angles. We predict that, depending on the relative lengths of the rods these particles can form a uniaxial nematic phase, and more surprisingly they can exhibit a cubatic phase, a special case of the b…
Based on a concise review of the experimental data, a theory of the structural, kinetic, and dynamic features of the Fischer cluster is put forward. This theory is based on the idea of heterophase fluctuations of glass-forming liquids. According to these ideas in a one-component liquid the solidlike and fluidlike tran…
A chiral liquid crystalline (LC) substituent with a fluorine-containing asymmetric moiety was introduced into the 3-position of a thiophene ring. Polymerizations of 2,5-dibrominated thiophene derivatives were carried out through dehalogenative polycondensations. Polythiophene derivatives thus prepared were fusible and…
Abstract A series of polymer–clay nanocomposite (PCN) materials consisting of polystyrene (PS) and layered montmorillonite (MMT) clay was prepared by effectively dispersing the inorganic nanolayers of MMT clay in the organic PS matrix via in situ thermal polymerization. Organic styrene monomers were first intercalated…
The A-site-ordered/disordered manganese perovskites, RBaMn 2 O 6 / R 0.5 Ba 0.5 MnO 3 (R = Y and rare earth elements), are reviewed. RBaMn 2 O 6 displays remarkable features: (1) the charge/orbital order (CO) transition at relatively high temperatures far above 300 K, (2) a new stacking variation of the CE-type CO wit…
Atomistic simulation calculations have been used to study disorder and deviation from stoichiometry in synthetic garnets A 3 B 5 O 12 as a function of A 3+ (Y 3+, Lu 3+ to La 3+ ) and B 3+ (Al 3+, Ga 3+, Fe 3+ ) ionic radius. Trends corresponding to the energy of several defect reactions have been obtained. Results co…
We measure the dispersion relation of capillary waves on a liquid surface by heterodyne x-ray photon correlation spectroscopy near the transition from propagating to overdamped dynamic behavior. A strong deviation of the propagation frequency from the small-damping result omega(p) proportional, variant k(3/2) is obser…
Interfacial glass transition temperature (T(g)) profiles in spin cast, ultrathin films of polystyrene and derivatives were investigated using shear-modulated scanning force microscopy. The transitions were measured as a function of film thickness (delta), molecular weight, and crosslinking density. The T(g)(delta) pro…
We have studied the chemical and material aspects of molecular precursor-derived materials taking the example of the spinel MgAl 2 O 4 . Three Mg−Al alkoxides, [MgAl 2 (OPr i ) 8 ], [MgAl 2 (OBu t ) 8 ] and [MgAl 2 (OBu t ) 4 H 4 ] were used as single molecular precursors in the gas-phase synthesis of the MgAl 2 O 4 f…
We present theoretical and experimental evidence for CO(2) adsorption on different sites of single walled carbon nanotube (SWNT) bundles. We use local density approximation density functional theory (LDA-DFT) calculations to compute the adsorption energies and vibrational frequencies for CO(2) adsorbed on SWNT bundles…
The crystallographic and magnetic phase diagram of the two-electron-doped system $({\mathrm{Ca}}_{1\ensuremath{-}x}^{2+}{\mathrm{Ce}}_{x}^{4+}){\mathrm{MnO}}_{3}$ with $0<~x<~0.167$ has been determined using neutron powder diffraction, synchrotron x-ray powder diffraction, small angle scattering, and ac suscepti…
A coupled-line coupler comprising a microstrip line, edge-coupled to a negative-refractive-index line, exhibits co-directional phase but contra-directional Poynting vectors on the lines, leading to backward coupling. A key feature of this coupler is that it can support complex coupled modes. The resulting exponential…
Investigation of glass transition dynamics in polyolefins by broadband dielectric spectroscopy (DRS) is facilitated by the addition of a novel dielectric probe, (4,4‘-( N,N -dibutylamino)-( E )-nitrostilbene (DBANS), which introduces dipoles and made the polymers dielectrically active. For probe concentrations between…
The high-resolution two-dimensional protein gel electrophoresis technique combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to analyse the oxidative stress response in Staphylococcus aureus COL. Exponentially growing cells were supplemented with 100 mM H…