Materials Literature
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Electron holography performed in situ inside a high resolution transmission electron microscope has been used to determine the magnitude and spatial distribution of the electric field surrounding individual field-emitting carbon nanotubes. The electric field (and hence the associated field emission current) is concent…
Substantial levels of hydrogen, up to 6.5 wt %, have been stored in carbon nanofibers (CNFs) under conditions of 12 MPa pressure and ambient temperature. The magnitude of this result cannot be interpreted in terms of physisorption on the external surface alone. Kinetic studies indicate that a slow chemisorption proces…
A “minimal-lithography” technique for chemically assembling small deterministic crossbars of single-walled carbon nanotube (SWNT) ropes: The formation of electrically conducting crossbar circuits with 8 to 14 junctions (see picture) from a suspension of SWNTs is described. The critical structural parameters of the cir…
The presence of 10-13 M of chiral clusters of aromatic amino acids addresses aggregation of opposite-charged achiral porphyrin towards the formation of smart chiral assemblies. The latter supramolecular complexes are able to self-propagate and transfer their chiral information with a 100% yield. The chiral bias occurs…
An intramolecular ferromagnetic interaction (see picture) is evidenced for the first time in a dinuclear gadolinium complex that has four carboxylate bridges. A similar interaction exists in a dinuclear erbium complex, but, as a result of the depopulation of the excited Stark levels, its signature only appears at very…
Green chemistry principles have gradually been implemented into the development of the synthetic chemistry of high-quality semiconductor nanocrystals. In comparison with the original organometallic approach, the resulting alternative routes are safe, simple, inexpensive, reproducible, versatile, "user friendly", and y…
The results of structural refinements on high-resolution powder neutron diffraction data for copper(II)- and copper(I)-exchanged zeolite Y and for the parent sodium zeolite Y, with composition Na 62 Si 128 Al 64 O 384, are presented. Rietveld refinement of ambient-temperature data shows that the Cu(I) and Cu(II) catio…
Methods of detection of amphetamine sulfate using surface enhanced Raman scattering (SERS) from colloidal suspensions and vapour deposited films of both silver and gold are compared. Different aggregating agents are required to produce effective SERS from silver and gold colloidal suspensions. Gold colloid and vapour…
We present theoretical description of conduction electrons interacting with a domain wall in ferromagnetic metals. The description takes into account interaction between electrons. Within the semiclassical approximation we calculate the spin and charge distributions, particularly their modification by the domain wall.…
A Comment on the Letter by P. Kratzer and M. Scheffler, Phys. Rev. Lett. 88, 036102 (2002).
Numerous compounds in which a paramagnetic LnIII ion is in an exchange interaction with a second spin carrier, such as a transition metal ion or an organic radical, have been described. However, except for GdIII, very little has been reported about the magnitude of the interactions. Indeed, for these ions both the lig…
We report a new scheme for attachment of functionalized organic molecules to polycrystalline diamond films. In this scheme, ultraviolet light is used to cause a local reaction between a hydrogen-terminated diamond surface and organic molecules present as a thin overlayer liquid film. Comparison of functionalized alken…
Multiple-walled carbon nanotubes (MWNTs) produced using the chemical vapor deposition method were functionalized via attaching aminopolymer poly(propionylethylenimine- co -ethylenimine) to the nanotubes. Two different reaction conditions based on acylating the nanotube-bound carboxylic acids and on directly heating na…
The threefold symmetry of planar boron nitride (BN), the III-V analog to graphene, prohibits an electric polarization in its ground state, but this symmetry is broken when the sheet is wrapped to form a BN nanotube. We show that this leads to an electric polarization along the nanotube axis which is controlled by the…
In this paper, we investigate as a function of erbium concentration (1, 2, 5, 10 mol %) the upconversion properties of bulk and nanocrystalline Er 3+ doped cubic Y 2 O 3 . After excitation at short wavelength (488 nm) or with upconversion pumping (815 nm), green and red emissions were observed for both nanocrystalline…
This work studied the loading capabilities and release behavior of poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) multilayer films, using methylene blue dye (MB) as an indicator. PAA/PAH multilayers assembled at pH = 2.5/2.5 loaded MB throughout the multilayers due to available binding sites and a p…
Recently, we have developed a new electron crystallography (EC) method for study of three dimensional (3D) structures of silica-mesoporous materials, and the 3D-structural solutions of MCM-48 and SBA-1, -6, and -16 were briefly reported. The method gives a unique structure solution through the Fourier sum of the 3D-st…
Work in mesoporous silica-based materials began in the early 1990s with work by Mobil. These materials had pore sizes from 20-500 A and surface areas of up to 1500 m(2) g(-1) and were synthesized by a novel liquid crystal templating approach. Researchers subsequently extended this strategy to the synthesis of mesoporo…
Simply changing the solvent or evaporation conditions enables the physical properties of polythiophene block copolymers and polyurethane elastomers to be controlled. The copolymers all have high conductivities as well as excellent film-forming and good mechanical properties, and well-defined nanowires that reach lengt…
This paper describes a simple and convenient procedure based on the Tollens process for the preparation of silver nanoparticles with a relatively narrow distribution in size. The starting reagents were similar to those commonly used in the electroless deposition of silver. Only under appropriate conditions, mixing of…