135,056 research outputs found
Portfolio Optimization under Small Transaction Costs: a Convex Duality Approach
We consider an investor with constant absolute risk aversion who trades a
risky asset with general Ito dynamics, in the presence of small proportional
transaction costs. Kallsen and Muhle-Karbe (2012) formally derived the
leading-order optimal trading policy and the associated welfare impact of
transaction costs. In the present paper, we carry out a convex duality approach
facilitated by the concept of shadow price processes in order to verify the
main results of Kallsen and Muhle-Karbe under well-defined regularity
conditions
Rectifying "nanohomo" contacts of W-Ga-C composite pad and nanowire fabricated by focused-ion-beam induced chemical vapour deposition
We prepared W-Ga-C composite contacts on W-Ga-C composite nanowires by focused-ion-beam-induced chemical vapor deposition using a dual-beam scanning electron microscope/focused-ion-beam system. The current-voltage (I-V) characteristics of wires were found to change from nonlinear to linear with increasing wire thickness. For wires with small dimensions, which result in strong nonlinear I-V behavior at room temperature, pairs of contacts were fabricated along the wire under different ion energies and scanning modes. Nonlinear and asymmetric rectifying I-V characteristics were observed. The results suggest that nanoscaled W-Ga-C nanowires may behave similarly to semiconductors and that the contact characteristics may be modified using different deposition conditions. Furthermore, ohmiclike junctions could be formed through the use of specific deposition conditions for the contact pads and nanowires
- …