Materials Literature
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All of the unique properties imparted by fluorocarbons can be traced back to a single origin: the nature of the C—F bond. These properties include low surface tension, excellent thermal and chemical stability, low coefficient of friction, and low dielectric constant. However, not all of these properties are possessed…
The preparation and characterization of the five-coordinate iron(II) porphyrinate derivative [Fe(TpivPP)(NO3)]- (TpivPP = picket-fence porphyrin) is described. Structural and magnetic susceptibility data support a high-spin state (S = 2) assignment for this species. The anionic axial nitrate ligand is O-bound, through…
Abstract After being subjected to preliminary purification, montmorillonite clay was leached with varying concentrations of sulfuric acid (0.5–2 mol L −1 ) at 90 °C for varying times (0.5–4 h). Acid leaching causes partial amorphization of the montmorillonite and increases its specific surface area by a factor of 3 (f…
The controlled generation of single photons is mandatory for applications in quantum communication, in particular for secure quantum cryptography, and also for a number of fundamental problems in quantum optics. Here, we present a stable all solid-state source for single photons utilizing the fluorescence light from a…
We incorporated cisplatin inside single-wall carbon nanohorns (NHs) and revealed that 70% of the cisplatin was released from NHs having holes with hydrogen-terminated edges when they were immersed in phosphate-buffered saline (PBS). However, only 15% was released from NHs having holes with oxygen-containing functional…
Single-walled carbon nanotubes functionalized by phenyl groups can be sulfonated in oleum (H 2 SO 4, 20% free SO 3 ) to give materials that exhibit high solubility in water as determined by centrifugation in conjunction with UV−vis−near-infrared measurements. Cryo-transmission electron microscopy images show that exte…
The temporal and spectral properties of luminescence from individual CdSe quantum dot-oligophenylene vinylene nanostructures (single quantum dots with conjugated organic ligands coordinated to the surface) are profoundly modified relative to blended films of the same components. These kinds of composite quantum dot-co…
Hexagonal nanodisks of ZnO were fabricated by a solution process using ZnO nanoparticles and their cathodoluminescence characteristics were investigated. Monochromatic cathodoluminescence images showed that luminescence was spatially localized near the boundary of the nanodisk and spectral analysis in conjunction with…
Nanocrystalline Ce(1)(-)(x)Ti(x)O(2) (0 < or = x < or = 0.4) and Ce(1-)(x)(-)(y)Ti(x)Pt(y)O(2)(-)(delta) (x = 0.15, y = 0.01, 0.02) solid solutions crystallizing in fluorite structure have been prepared by a single step solution combustion method. Temperature programmed reduction and XPS study of Ce(1)(-)(x)Ti(x)O(2)…
A fast and reliable method is reported for fabricating superhydrophobic surfaces. The method combines microstructure replication with polymer phase inversion and can be applied to a wide variety of polymers. This method provides a surface that contains roughness on two independently controllable levels, i.e., the micr…
We present here a novel and simple synthetic strategy for fabricating superparamagnetic nanomagnets randomly dispersed in porous carbons. The method can be basically considered as a pyrolysis performed inside the restricted volume formed by the pores of an activated carbon. Such magnetic porous materials exhibit large…
Straightening out chirality: Chiral mesostructured silica nanofibers of MCM-41 with one (see TEM image, the arrows indicate periodic fringes) and two twist axes were fabricated from a simple dilute synthesis system without any chiral additives. A continuous transformation from a chiral mesostructure to an achiral stra…
Chitin is a key component in mollusk nacre formation. However, the enzyme complex responsible for chitin deposition in the mollusk shell remained unknown. We cloned and characterized the chitin synthase of the marine bivalve mollusk Atrina rigida. We present here the first chitin synthase sequence from invertebrates c…
We report on the realization of ZnO homojunction light-emitting diodes (LEDs) fabricated by metalorganic chemical vapor deposition on (0001) ZnO bulk substrate. The p-type ZnO epilayer was formed by nitrogen incorporation using N2O gas as oxidizing and doping sources. Distinct electroluminescence (EL) emissions in the…
A spontaneous luminescence is reported when epoxy resin samples are heated in air. This phenomenon is very sensitive to the nature of the atmosphere. The same treatment in nitrogen leads to an extinction of the luminescence. The emission process is restored when samples are kept for a sufficient time in air. In order…
The metal-support interactions on a series of catalysts of different acidities, including platinum-modified zeolites and H-MCM-41, are investigated by means of XPS, CO and pyridine adsorption, and a model reaction (ring opening of decalin). The electronic properties of Pt are influenced by the acidity of the support,…
Using high precision Monte Carlo simulations and a mean-field theory, we explore coarsening phenomena in a simple driven diffusive system. The model is reminiscent of vehicular traffic on a two-lane ring road. At sufficiently high density, the system develops jams (clusters) which coarsen with time. A key parameter is…
Rubber composites containing multiwalled carbon nanotubes have been irradiated with near-infrared light to study their reversible photomechanical actuation response. We demonstrate that the actuation is reproducible across differing polymer systems. The response is directly related to the degree of uniaxial alignment…
We investigate photoluminescence from a high-density electron-hole plasma in semiconductor quantum wells created via intense femtosecond excitation in a strong perpendicular magnetic field, a fully-quantized and tunable system. At a critical magnetic field strength and excitation fluence, we observe a clear transition…
The influence of an externally applied magnetic field upon classic cubic quintic dissipative solitons is investigated using both exact simulations and a Lagrangian technique. The basic approach is to use a spatially inhomogeneous magnetic field and to consider two important geometries, namely the Voigt and the Faraday…