Materials Literature
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We present detailed information on the fabrication of free-standing ultrathin porous alumina membranes (PAMs) with controllable thickness of 100–1000 nm. The mechanism of the ultrathin PAM formation has been revealed by a combination study of current–time characteristics and microstructure images. At the beginning of…
Many potential applications in nanotechnology require virtually defect-free arrays of nanometre-scale particles over large areas. Guided self-assembly of colloidal particles on patterned templates has been shown to produce ordered arrays of colloidal particles. However, there is a need to extend this technique to part…
Here we report the hierarchical self-assembly of a cross-linkable coiled-coil peptide containing an internal cysteine. Atomic force microscopy (AFM) experiments revealed the fractal structure of the assemblies, and molecular simulations showed that the peptides cross-linked to form clusters of coiled-coils, which furt…
The dynamical conductance of electrically contacted single-walled carbon nanotubes is measured from dc to 10 GHz as a function of source-drain voltage in both the low-field and high-field limits. The ac conductance of the nanotube itself is found to be equal to the dc conductance over the frequency range studied for t…
In this paper we describe printing methods for transferring single-walled carbon nanotubes (SWNTs) from high-temperature growth substrates to flexible, low-cost plastic supports. Thin-film transistors (TFTs) built with networks of transferred SWNTs grown by chemical vapor deposition show good performance—mobilities an…
Single-crystalline SiC nanowires (NWs) with a SiO2 coating (see Figure) have been grown using electrospun polyacrylonitrile nanofibers as templates. SiC NWs produced in this process have uniform cross-sections, well-ordered structures, and very low concentrations of stacking faults, and contain no catalyst. Some bent…
Scanning tunneling spectroscopy (STS) measurements were made on surfaces of two different kinds of graphite samples, Kish graphite and highly oriented pyrolytic graphite (HOPG), at very low temperatures and in high magnetic fields. We observed a series of peaks in the tunnel spectra associated with Landau quantization…
Spin-density-functional theory (SDFT) is the most widely implemented and applied formulation of density-functional theory. However, it is still finding novel applications, and occasionally encounters unexpected problems. In this paper we first briefly describe a few of the latter, related to issues such as nonuniquene…
We report the realization of nanotube-based multiple quantum dots that are fully defined and controlled with electrostatic gates. Metallic top-gates are used to produce localized depletion regions in the underlying tubes; a pair of such depletion regions in a nanotube with ohmic contact electrodes defines the quantum…
A double hydrophilic block copolymer (DHBC) is used as a crystal-growth modifier for controlled self-assembly of complex and unusual calcite pancakes with multiple stacked and porous layers (see Figure), based on a polymer-directed crystallization mechanism. The results demonstrate that it is possible to manipulate th…
[structures: see text] Bacteriochlorins (tetrahydroporphyrins) are attractive for diverse photochemical applications owing to their strong absorption in the near-infrared spectral region, as exemplified by the bacterial photosynthetic pigment bacteriochlorophyll a, yet often are labile toward dehydrogenation to give t…
Proposed is a substantially simplified, Preisach-like model for characterization of hysteretic systems, in particular magnetic systems. The main idea is to replace a two-dimensional Preisach density with just two real functions, describing in a {\em unique way} the reversible and irreversible processes. As a byproduct…
From recent Hall effect measurements and angle-resolved photo-emission spectroscopy the interesting picture emerges of co-existing hole- and electron-like quasiparticle bands, both in electron- and hole-doped superconducting cuprates. We reflect on the idea that bosonic electron-hole pairs may be formed in the cuprate…
The 120\ifmmode^\circ\else\textdegree\fi{} ordered antiferromagnetic state of the Hubbard model on a triangular lattice presents an interesting case of $U$-controlled competing interactions and frustration. The spin stiffness is found to vanish at $U\ensuremath{\approx}6$ due to competing spin couplings generated at f…
SiC nanowires (NWs) reinforce SiC matrix composites with high efficiency. With the incorporation of ∼ 6 vol.-% randomly oriented single-crystal SiC NWs in the matrices, the fracture toughnesses and flexural strengths of the composites doubled. The composites (see Figure) were fabricated in situ by a new process based…
We report the writing of very high resolution tungsten containing dots in regular arrays by electron beam-induced deposition (EBID). The size averaged over 100 dots was 1.0 nm at fwhm. Because of the statistical spread in the dot size, large and small dots are present in the arrays, with the smallest having a diameter…
Crystalline hexagonal-shaped superstructures of calcium carbonate, synthesized in the presence of ammonia, are shown to be assembled by a three-dimensional oriented attachment of vaterite nanoparticles. This unusual crystallographic lock-in mechanism enables the formation of complicated rounded structures with a cryst…
A fully inorganic analogue of the nanostructured dye-sensitized solar cell is fabricated using an electrochemically grown n-ZnO/CdSe core–shell nanowire array (see Figure). Filling the voids between the nanowires with p-type wide-bandgap CuSCN by a solution-deposition technique leads to an extremely thin solar cell ex…
The effect of citric acid and 1,2-dihydroxybenzene 3,5-disulfonic acid (DHBDSA), as additives, on the crystallization of gypsum was studied under simulated conditions of the of phosphoric acid production. Calcium hydrogen phosphate and sulfuric acid were mixed with dilute phosphoric acid at 80 °C, and the turbidity of…
Abstract The chemical modification of maritime pine sapwood ( Pinus pinaster Soland) with 3-isocyanatopropyltriethoxysilane (IPTES) and its subsequent hydrolysis were investigated. The formation of urethane linkages after the carbamoylation reaction was confirmed by Fourier-transform infrared (FTIR) spectroscopy. The…