Materials Literature
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A newly designed donor-acceptor substituted molecular motor 1 allows unidirectional rotation driven by visible light and shows some unique photophysical properties.
We have investigated the supramolecular structure of helical ribbons formed during self-assembly of a β-sheet peptide using computer simulation. We tested a wide range of molecular packing geometries consistent with the experimental dimensions to identify the most stable structure, and then systematically changed the…
ZSM-5- and NaY-coated MCF materials as new acid catalysts for conversion of bulky molecules were prepared by the coating procedure using diluted clear zeolite gel solutions. The resulting materials have high acidity and improved steam stability as compared to that of the corresponding MCF aluminosilica. This could be…
The results of first-principles density-functional calculations of the bulk moduli and related structural and electronic properties of all III-V and IV binary zinc-blende structures are presented. The band types and other properties for all the known materials in these two classes are correctly estimated. In studying…
Femtosecond coherence spectroscopic study on porphyrin molecules has demonstrated that the oscillatory features residing at the transient absorption and fluorescence decay profiles are strongly correlated with the lifetimes of the excited states and the displacements of the minima of the potential energy surfaces that…
We propose a scheme for extending the model Hamiltonian method developed originally for studying the equilibrium properties of complex perovskite systems to include Langevin dynamics. The extension is based on Zwanzig's treatment of nonlinear generalized Langevin's equations. The parameters entering the equations of m…
ZnO quantum dots (QDs) were fabricated on SiO2/Si substrates by metalorganic chemical vapor deposition. The densities and sizes of dots were investigated by atomic force microscopy. Photoluminescence at 10 K showed the broad spectra with band tails up to about 3.55 and 3.65 eV for the as-grown and the annealed ZnO QDs…
We examined the eigenstates of the Heisenberg spin Hamiltonian Ĥ=−JŜ1⋅Ŝ2 and the Ising spin Hamiltonian ĤIsing=−JŜ1zŜ2z for a general spin dimer consisting of M unpaired spins at one spin site and N unpaired spins at the other spin site, and then analyzed how the broken-symmetry spin state of a spin dimer is related t…
By using nanosecond laser pulses at 532-nm wavelength, we have studied the nonlinear optical properties of composites which consist of mono-functional 1,2-dihydro-1,2-methanofullerene[60]-61-carboxylic acid (FCA) and poly(styrene-co-4-vinylpyridine). The optical limiting performance of FCA itself is poorer than that o…
Recently, the nucleation rate on top of a terrace during the irreversible growth of a crystal surface by MBE has been determined exactly. In this paper we go beyond the standard model usually employed to study the nucleation process, and we analyze the qualitative and quantitative consequences of two important additio…
The temperature dependent frequency shifts of the Raman active G-band have recently been measured by R.Walter et al. for single-walled carbon nanotubes containing different concentrations of the magnetic impurity Ni:Co. These Raman data can be quantitatively explained by magnetic pair-breaking effect on a superconduct…
We theoretically estimate the electron-phonon coupling constant lambda for metallic single-walled carbon nanotubes with a diameter of 1.4 nm. The partial electron-phonon coupling constant for the hardest phonon mode is estimated to be about 0.0036, in good agreement with that deduced from Raman scattering data assumin…
Single-crystalline MoO3 nanobelts having an orthorhombic structure were prepared on a Si wafer via heating a Mo foil in air. The nanobelts were 50–300 nm wide and tens of nanometers thick. The nanobelt lengths lie in the [001] direction. Field-emission measurements showed that the threshold field decreased with the an…
Using nonequilibrium molecular dynamics simulations in which a temperature gradient is imposed, we determine the thermal resistance of a model liquid–solid interface. Our simulations reveal that the strength of the bonding between liquid and solid atoms plays a key role in determining interfacial thermal resistance. M…
We show that by annealing Ga1−xMnxAs thin films at temperatures significantly lower than in previous studies, and monitoring the resistivity during growth, an unprecedented high Curie temperature TC and conductivity can be obtained. TC is unambiguously determined to be 118 K for Mn concentration x=0.05, 140 K for x=0.…
Amide and alkoxide coordination complexes of calcium supported by beta-diiminato and bulky trispyrazolylborate complexes are reported together with their activity in lactide ring-opening polymerization; some are amongst the most active systems discovered to date.
New mesoporous niobium oxides with 5, 10, and 15 mol% vanadium(V) doped into the walls of the structure were synthesized by the ligand-assisted templating method with an octadecylamine template. These materials were characterized by XRD, XPS, EPR, elemental analysis, and nitrogen adsorption before being treated with e…
Theoretical calculations demonstrate that the presence of ligands with different basicity modifies the Lewis acidity (expressed both as the LUMO energy and the enthalpy of coordination of a NH 3 molecule) of the active centers in silica-supported titanium catalysts. Several catalysts containing different organic ligan…
The reduction of a phenylene-bridged bis(dioxaborine) affords a strongly delocalised organic mixed-valence system; for the first time details of the vibrations coupled to the electron transfer have been extracted from the intervalence band.
The electrochemical deposition and reoxidation of Au on the basal plane of highly oriented pyrolytic graphite (HOPG) immersed in a 5 mM AuCl 4 - /6 M LiCl solution is reported. Scanning electron microscopy (SEM) and ex-situ atomic force microscopy (AFM) demonstrate that Au nanoparticles, ∼3.3 nm in height and ∼10 nm i…