Materials Literature
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Low-frequency Raman spectra are performed on silver nanocrystals self-organized on a hexagonal compact array on highly oriented pyrolytic graphite (HOPG) substrate. In addition to the well-known Raman scattering by the nanoparticle quadrupolar vibration mode, two lower intensity bands at larger frequency shifts are ob…
Unsymmetrically substituted tetraphenylporphyrins, including A2B2 and AA′B2 types can be synthesised by bromination of 5,15-diphenylporphyrins followed by palladium catalysed Suzuki coupling to arylboronic acids and esters. Unsymmetrically substituted triphenylporphyrins are also accessed via partial debromination in…
STM data show that gold exhibits homogeneous nucleation and growth on polycrystalline titania surfaces. When very small Au particles are exposed to ambient air at room-temperature rapid sintering occurs (∼20 nm) accompanied by Au migration to titania crystallite grain boundaries. This process is driven principally by…
Lithium diffusion in amorphous LiNbO3, synthesized by a sol–gel process, was investigated by temperature- and frequency-dependent 7Li NMR experiments. 7Li spin-lattice relaxation rates T−11 and 7Li nuclear magnetic resonance spectra, in particular line shapes and motional narrowing of the central line, were measured.…
Starting from the united atom model, we construct a coarse-grained model for a flexible polymer chain, in which some successive CH2 atoms are combined into an effective segment. To connect the coarse-grained model with the atomistic model, we propose a scheme to obtain the effective potentials acting between bonded an…
We have investigated the complexation of the luminescent Nd(3+), Eu(3+), Gd(3+), Tb(3+), Er(3+), and Yb(3+) ions by a polylysin dendrimer containing 21 amide groups in the interior and, in the periphery, 24 chromophoric dansyl units which show an intense fluorescence band in the visible region. Most of the experiments…
We report the epitaxial growth of CdCr2Se4, an n-type ferromagnetic semiconductor, on both GaAs and GaP(001) substrates, and describe the structural, magnetic and electronic properties. Magnetometry data confirm ferromagnetic order with a Curie temperature of 130 K, as in the bulk material. The magnetization exhibits…
In the ferromagnetic metallic state of the colossal magnetoresistive (CMR) manganite La1.2Sr1.8Mn2O7, the spin density distribution is essentially in agreement with the standard picture in which the unpaired electrons occupy the three t2g orbitals, dxy, dyz, and dxz. However we find a small spin density ~4% of the tot…
Ca$_3$Ru$_2$O$_7$ undergoes an antiferromagnetic transition at $T_{\text{N}}=56 $K, followed by a Mott-like (MI) transition at $T_{\text{MI}}=48$ K. This nonmetallic ground state, with a charge gap of 0.1 eV, is suppressed by a highly anisotropic metamagnetic transition that leads to a fully spin-polarized metallic st…
The least action principle is exploited as a simulation tool to find the optimal dynamic path for spatially extended systems driven by a small noise. Applications are presented for thermally activated switching of a spatially-extended bistable system as well as the switching dynamics of magnetic thin films. The issue…
Magnetic-resonance-imaging rheometrical experiments show that concentrated suspensions or emulsions cannot flow steadily at a uniform rate smaller than a critical value ( ${\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\gamma}}}_{c}$). As a result, a ``liquid'' region (sheared rapidly, i.e., at a rate larger t…
Highly ordered TiO 2 single-crystalline nanowire arrays have been fabricated within the pores of anodic aluminum oxide (AAO) template by a cathodically induced sol−gel method. Raman spectra confirmed that the nanowires are composed of pure anatase TiO 2 . TEM investigations indicated that these nanowires have a unifor…
For the first time, a CO-bridged primary photoproduct was observed for [Ru3(CO)12] by using picosecond time-resolved IR spectroscopy (ps-TRIR).
Ionic conductivities in a range of LixNa(1−x)PO3 glasses are reported as a function of both temperature and pressure. This series of mixed-cation glasses characteristically exhibits minima in glass transition temperatures and in ionic conductivities, and a maximum in the activation energy for ionic conductivity. There…
Original and homogeneous macrotextures shaped with coral-like, helical or macroporous sieves morphologies are obtained following a nanotectonic approach based on the template-directed assembly by poly-gamma-benzyl-L-glutamate (PBLG) of organically functionalised CeO2 crystalline nanoparticles.
Abstract A new bulky pendent bis(ether anhydride), 1,1‐bis[4‐(4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane dianhydride, was prepared in three steps, starting from the nitrodisplacement of 1,1‐bis(4‐hydroxyphenyl)‐4‐phenylcyclohexane with 4‐nitrophthalonitrile to form bis(ether dinitrile), followed by alkaline hydrol…
Abstract Research into azobenzene and its compounds focuses on the molecules ability to cis‐trans isomerize, this photoisomerization enables surface relief gratings (SRGs) to be formed on the azobenzene functionalized polymer films. SRG allows information to be written and then erased, an essential requirement of most…
Abstract To clarify the relationship between a molecular deformation mechanism and a high Young's modulus of poly‐ p ‐phenylenebenzobisoxazole (PBO), Raman spectra were measured for fibers subjected to a tensile stress along the chain axis. The stress‐induced frequency shift of the observed Raman bands could be reprod…
The partial oxidation of methane to CH3OH and HCHO (C1-oxygenates) was evaluated over a low surface area V2O5/SiO2 catalyst. The introduction of low amounts of NO (0-2.92% vol) to the reaction feed strongly enhanced both the conversion of methane and selectivity to C1-oxygenates. In the presence of NO, both the reacti…
Polythiophene (Pth) films have been electrochemically deposited on mirror-like stainless steel (SS) (or gold) electrode surfaces by direct oxidation of thiophene in boron trifluoride diethyl etherate (BFEE) solutions at a constant applied potential of 1.3 V (vs. Ag/AgCl). The Raman spectra of Pth films have been inves…