Materials Literature
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Electronic transport in semiconducting single-wall carbon nanotubes is studied by combined scanning gate microscopy and scanning impedance microscopy (SIM). Depending on the probe potential, SIM can be performed in both invasive and non-invasive mode. High-resolution imaging of the defects is achieved when the probe a…
We carry out a self-consistent analytical theory of unipolar current and noise properties of metal-semiconductor-metal structures made of highly resistive semiconductors in the presence of an applied bias of arbitrary strength. By including the effects of the diffusion current we succeed to study the whole range of ca…
The anisotropy of MgB2 is still under debate: its value, strongly dependent on the sample and on the measuring method, ranges between 1.2 and 13. In this work we present our results on a MgB2 c-oriented superconducting thin film. To evaluate the anisotropy, we followed two different approaches. Firstly, magnetoresisti…
Quantum Monte Carlo (QMC) calculations of the optical gaps of silicon quantum dots ranging in size from 0 to 1.5 nm are presented. These QMC results are used to examine the accuracy of density functional (DFT) and empirical pseudopotential based calculations. The GW approximation combined with a solution of the Bethe-…
ZnO thin films have been deposited on Corning 7059 glass at room temperature using r.f. magnetron sputtering. Strong monochromatic blue emission located at 446 nm is observed when excited with 270 nm light. The photoluminescence intensity of the blue emission peak decreases with increasing oxygen pressure and substrat…
Single amine functionalized CdSe quantum dots were coupled to individual acid-chloride modified single-walled carbon nanotubes via amide bond formation. The quantum dot−nanotube conjugates were characterized by atomic force and transmission electron microscopies. For single-walled nanotubes with lengths of < 200 nm, b…
Electrogenerated chemiluminescence (ECL) was observed from TOPO-capped CdSe nanocrystals dissolved in CH 2 Cl 2 containing 0.1 M TBAP. The solution of monodisperse nanocrystals with an absorption maximum at 537 nm was synthesized at 330 °C using TOPO (trioctylphosphineoxide) and TOP (trioctylphosphine) as capping agen…
<div class="htmlview paragraph">NO<sub>2</sub> is an effective soot oxidizer operating at lower temperatures than O<sub>2</sub>. The effect of pure NO<sub>2</sub> on soot oxidation was evaluated and compared with the gas treated by plasma, which initially consisted of NO, O<…
We report on the changes in the defect structure of ZnO particles that take place during the grinding of pure ZnO powders and mixtures ZnO–SnO2 and ZnO–TiO2 powders. The qualitative differences in the electron paramagnetic resonance spectra for different specimens were discussed in the context of the hyper-rapid high-…
Abstract We used readily available commercial reagents and well‐known procedures to synthesize a series of aromatic imine mesogenic diglycidylester compounds with dimeric architectures. The compounds obtained were characterized by spectroscopic techniques. Their liquid‐crystalline behavior was examined by differential…
In situ synchrotron x-ray scattering is used in conjunction with a novel annular cone and plate shear cell to study the nonequilibrium structure factor of a polymer bicontinuous microemulsion within the flow-gradient plane. At equilibrium the scattering is well described by the Teubner-Strey structure factor. In stead…
Bi 4 Ti 3 O 12 – SrBi 4 Ti 4 O 15 (BT–SBTi) thin film was fabricated successfully on Pt/TiO2/SiO2/Si(110) substrates by the pulsed laser deposition technique. Films annealed at 650 °C by the rapid temperature process (RTP) have Pr=12 μC/cm2. But, the fatigue behavior has been observed although no obvious decrease in P…
Collaborative Computational Project Number 4 (CCP4) was established in 1979 to promote collaboration between UK groups writing software for protein crystallography. From these beginnings, CCP4 now distributes a large software suite and is active in developing new software. In this article, an overview is given of rece…
We studied room-temperature transient creep in polycrystalline, free-standing Al films with a thickness between 220 and 550 nm using a high-resolution bulge test technique. A transient logarithmic creep strain is observed. The time and stress dependence of the creep strongly support the idea that dislocation glide, li…
The electrical discharge of volume distributed space charge in poly(methylmethacrylate) (PMMA) has been investigated both experimentally and by computer simulation. The experimental space charge was implanted in dielectric samples by exposure to a monoenergetic electron beam of 3 MeV. Electrical breakdown through the…
Supersonic cluster beam deposition has been used to produce films with different nanostructures by controlling the deposition parameters such as the film thickness, substrate temperature and cluster mass distribution. The field emission properties of cluster-assembled carbon films have been characterized and correlate…
Block copolymers adsorbing to an interface between two immiscible homopolymers modify the elastic constants of this interface. Within self-consistent field calculations for Gaussian chains, we determine how the bending constants vary in dependence on the block copolymer concentration and architecture. Four phenomena a…
<div class="htmlview paragraph">Improving catalyst light-off characteristics during cold start and reducing engine-out (more accurately converter-in) emissions prior to catalyst light-off have been regarded as the keys to meeting future stringent emissions regulations. Many technologies and control strategies ha…
Raman spectra of nickel cobalt oxide films with spinel crystal structure showed unexpected variations with film thickness. Combined with the results of studies as a function of incident laser power and temperature, from 25 to 800 K, the results strongly point to a small polaron hopping model for electrical conductivit…
We report on low threshold photopumped amplified spontaneous emission (ASE) in blends of derivatives of poly (p-phenylene vinylene) and distributed feedback (DFB) lasers fabricated from the same materials. Förster energy transfer is used to spectrally shift the emission away from the absorption band, thereby reducing…