Relational Structure of Measurement with Application on Specification of Freeform Surface

A contradiction is shown in this paper that, for contact surface measurement, if a measured surface profile is exactly coincident with the USL (upper specification limit), the measured result may still be out of specification. To understand and avoid this contradiction, a relational construction of measurement is proposed bases on the representational measurement theory. By observing the connection between measurement and inverse problem, measurement is modeled as a mapping from the preordered set of measurands (objects to be measured) to the partially ordered set of measured values. Thereby, a desired property of the specifications limits is derived, and a correction of the USL of surface profile is proposed

Is the U.S. Stock Market Sufficiently Efficient around Hurricanes?

This paper tests the U.S. stock market efficiency around all 18 hurricanes that have hit continental U.S. since 2000. Using an event-study methodology, the study analyzes the effect of those 18 hurricanes on a sample of 60 property-casualty insurance companies before and following the hurricanes’ landfall. The study supports the semi-strong form market efficiency and concludes that market inefficiency only exists during the pre-landfall period. Moreover, a significant negative relationship is found between the wind speed and firms’ risk exposure, which reiterates the market’s ability to differentiate hurricanes by their damaging power and to discriminate P&C insurers by their existence of exposure

Doping dependent charge injection and band alignment in organic field-effect transistors

We have studied metal/organic semiconductor charge injection in poly(3-hexylthiophene) (P3HT) field-effect transistors with Pt and Au electrodes as a function of annealing in vacuum. At low impurity dopant densities, Au/P3HT contact resistances increase and become nonohmic. In contrast, Pt/P3HT contacts remain ohmic even at far lower doping. Ultraviolet photoemission spectroscopy (UPS) reveals that metal/P3HT band alignment shifts dramatically as samples are dedoped, leading to an increased injection barrier for holes, with a greater shift for Au/P3HT. These results demonstrate that doping can drastically alter band alignment and the charge injection process at metal/organic interfaces.Comment: 5 pages, 4 figure