From a field-theoretical approach, it has been possible to develop a physically valid theory of partial discharge transients. Thetheoryis baseduponthe concept of the charge induced upon the detecting electrode by the partial discharge. This induced charge is shown tobe composedo f a componentassociated withtheactual spacecharge inthevoid, and one related to changes in the bulk po la r i za t io...

Measurements of the energy resolution and the peak-to-background ratio of a Silicon Drift Detector at several positions and biasing voltages are performed. The origins of events with partial charge collection, which contribute to the background, are identified. A model describing the different mechanisms and the spatial distribution of partial events is developed. By optimizing the biasing volt...

The variations of the electrical conductivity with temperature and electric field of the ternary alloy of gallium, aluminium and arsenic (Al0.75Ga0.25As) with atomic compositions of 99/1 and 98/2 have been investigated. The electrical conductivity of the alloy increases with temperature according to the relation, ? = ?0 exp (??/kT). The activation energy calculated from this empirical relation ...

Upon release of engineered nanoparticles (NPs) into the subsurface environment, their fate and transport and hence their potential environmental and public health impacts will largely depend on how stable these NPs are as suspended particles in the natural environment. In this study, we systematically examine the effect of humic acid (HA) on surface charge status and aggregation potential of ma...

A method is presented for extending any bond-order potential (BOP) to include charge transfer between atoms through a modification of the split-charge equilibration (SQE) formalism. Variable limits on the maximum allowed charge transfer between atomic pairs are defined by mapping bond order to an amount of shared charge in each bond. Charge transfer is interpreted as an asymmetry in how the sha...

The charge distribution in atoms with closed electron shells is spherically symmetric, whereas atoms with partially filled shells can form covalent bonds with pointed lobes of increased charge density. Covalent bonding in the bulk can also affect surface atoms, leading to four tiny humps spaced by less than 100 picometers in the charge density of adatoms on a (001) tungsten surface. We imaged t...

In this study, we have mapped the surface charge of wool fibers using chemically specific high-resolution force spectroscopy in order to better understand the dispersion of amino acids in relation to fiber morphology. The inter-surface forces between standard atomic force microscopy (AFM) probe tips (tip radius ~ 50 nm) functionalized with COOH and NH(3) terminated alkanethiol self assembling m...

Low-energy spin and charge excitations of one-dimensional interacting fermions are completely decoupled and propagate with different velocities. These modes, however, can decay due to several possible mechanisms. In this Letter we expose a new facet of spin-charge separation: not only the speeds but also the damping rates of spin and charge excitations are different. While the propagation of lo...

In this Report we show the role of charge defects in the context of the formation of electrostatically defined quantum dots. We introduce a barrier array structure to probe defects at multiple locations in a single device. We measure samples both before and after an annealing process which uses an Al2O3 overlayer, grown by atomic layer deposition. After passivation of the majority of charge def...

In the present work, the structural and electronic properties, and conductivity of (5,5) and (6,6) Single Walled Carbon Nanotubes in the ground state have done by using the Hartree-Fock and density functional theory DFT-B3LYP/6-31G* level. Delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by NBO (natural bond orbital) analysis. These methods a...