[en] The electronic properties of saturated and unsaturated twinned SiC nanowires grown along [111] direction and surrounded by {111} facets are investigated using first-principles calculations with density functional theory and generalized gradient approximation. All the nanowires considered, including saturated and unsaturated ones, exhibit semiconducting characteristics. The saturated nanowires have a direct band gap and the band gap decreases with increasing diameters of the nanowires. The hexagonal (2H) stacking inside the cubic (3C) stacking has no effect on electronic properties of the SiC nanowires. The highest occupied molecular orbitals and the lowest unoccupied molecular orbitals are distributed along the nanowire axis uniformly, which indicates that the twinned SiC nanowires are good candidates in realizing nano-optoelectronic devices.

[en] We report a study on the effects of various parameters on the synthesis of silicon nanowires (5--50 nm in diameter) by pulsed laser ablation. A novel silicon nanodendrite structure is observed by changing some of the growth parameters abruptly. This growth mechanism is explained by a qualitative model. These nanodendrites show a promise of being used as a template in fabricating nanocircuits. Thermal quantum confinement effects were also observed on the silicon nanowires and have been reported

[en] The quantum conductance phenomena in narrow metal nanobridges were investigated. The nanobridge devices with small atomic-wide gap were formed by a novel controlled electroplating method on a nanolithographed quartz wafer. The metallic contact nanowires were grown across the gap by field evaporation. The field-induced formation and field-stabilization of monatomic Ni nanobridges are described. Thus formed Ni nanowires appeared to be unstable in the absence of electric field and disassembled quickly under no field conditions. The minimum quantum conductance associated with monatomic constriction in the nanobridge was observed. Exceptionally stable monatomic quantum nanobridges (QNB) were obtained by chemical treatment. They were investigated in the dry state and in the electrolyte solutions. The quantum conductance with zero temperature coefficient was observed at low electric field strength E (bias voltage |V _b| < 0.3 V) but thermionic conductance dominated at higher E (|V _b| > 0.8 V) leading to the conductance increase with temperature, opposite to the behavior of a bulk Ni metal. The mechanism of the observed phenomenon is presented. To gain further insights into the thermionic barrier formation in QNB, we have performed quantum mechanical calculations, using semi-empirical method, for model Ni nanobridge atom clusters (base:nanowire:base = 6:n:6 atoms, with n = 1-5). They have shown that in longer joining nanowires (n > 1) the lowest unoccupied molecular orbitals (LUMO) are predominantly concentrated over base electrodes (reservoirs) rather than over the nanowire constriction, while the short (monatomic) nanowires are densely populated with low lying LUMO's. The results of calculations suggest also that the location of the quantum confinement (the constriction) may not necessarily be at the nanowire center (as generally assumed) but rather at the joints of nanowire with base electrodes where the wire width is the lowest

[en] We present a phenomenological model for the interaction field in ferromagnetic nanowire arrays and use it to obtain the effective anisotropy field of individual nanowires, from the in-plane saturation field of the array. In contrast to other methods which may be used to estimate this parameter, the proposed strategy requires no knowledge of the saturation magnetization nor of the nanowire radius. Applied to three arrays of different compositions, this approach yields an equivalent anisotropy field of the individual nanowires approximately equal to M_s/2, indicating that its origin is the demagnetizing field of the wire

[en] The Micro Gap Wire Chambers (MGWC) proposed as tracking detector are now operated with a 2D readout. The first coordinate is obtained by reading the anode wires whilst the second one is given by the segmentation of the cathode plane into strips. For this configuration a very important parameter is the anode-cathode coupling, the amount of charge recorded by the cathode strips compared to the one induced on the corresponding anode wire. Using a 50 μm Kapton substrate, an anode-cathode coupling higher than 95% was obtained

[en] Magnetic structures and magnetization processes of individual Ni nanowires with constrictions are investigated by means of micromagnetic modeling. The physical problem is modeled with the Landau-Lifshitz-Gilbert (LLG) equation, and the fast Fourier transform on multipoles (FFTM) method is employed to speed up the calculation of the demagnetization field. It is demonstrated that the FFTM algorithm is efficient and accurate for studying magnetization transition configuration in nanowire. The new approach is then used to study the switching phenomenon of the nanowire. And the simulation results show that the switching field increases a little with presence of constriction. The investigation of the magnetization processes illustrates the edge domain forms near constriction region for nanowire with diameter=30 nm and vortex domain for 200 nm case

[en] Here we develop a simple electrochemical method to fabricate novel multibranched root-tailed nanorod arrays by a novel electrochemical technique. A formation mechanism of the thick barrier layer and the root-tailed nanorod is proposed. Using this template-assisted method, three-dimensional nanorod arrays were prepared in a controlled manner, which helped to clarify the growth processes close to the bottom of the nanopores. The nanobranched wire, distinct from previous one-dimensional nanowires, should have potential applications in three-dimensional nanoelectronics and nanophotonics

No abstract available

[en] A method is described for fabricating a superconducting wire comprising the steps of: in a first means, sputter depositing on a base wire a partial superconduction layer consisting of at least some, but not all, of the elements of an HTS material; and in a second means, reacting said partial superconduction layer with the other element or elements, including at least one metallic element, of the HTS material so that a complete superconduction layer is formed on said base wire

[en] A wire-chamber module with a small nonworking volume is described which is especially convenient when the outer dimensions of the chamber are bounded. The reduction of the volume is achieved by reducing the width of the flaps of the module. The flaps were subjected to preliminary stressing in order to increase mechanical strength. A chamber is fabricated having the dimensions 93x93 cm, an interelectrode gap of 1 cm, and a slat width approximately 4 cm