Search

The aerodynamic instability of a long-span suspension bridge with a shallow streamlined box girder is a serious engineering concern, particularly during the early deck erection stage. Its characteristics are significantly influenced by the sequence of deck erection. Using the Hoga Kusten Bridge in Sweden as an example, this paper presents an analytical and experimental discussion regarding the evolution of flutter characteristics for a long-span suspension bridge, and a comparison of different erection sequences and analytical prediction of more stable configurations. The general feature of the flutter limit evolution with the erection program of midspan to pylons, which was previously evidenced by wind tunnel tests, has been successfully reproduced analytically, and the advantages of keeping nonsymmetric deck configurations were confirmed. The pylon to midspan program has never been employed for long-span girder bridges, but it was found to be, at least, aerodynamically favorable.

Near-normal incidence infrared reflectivity spectra of (001) strontium lanthanum aluminate (SrLaAlO[sub 4]) single crystal have been measured under different temperatures in the frequency region between 100 and 6500 cm-1. Five phonon modes are distinguished at low frequency while no spectral features were observed above 1000 cm-1. All the reflectivity spectra are fitted with the factorized form of the dielectric function. The dielectric properties of the SrLaAlO[sub 4] crystal in far-infrared region are presented and analyzed. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report the design, fabrication, and characterization of room-temperature Si single-electron memories using nanoimprint lithography (NIL). The devices consist of a narrow channel metal–oxide–semiconductor field-effect transistor and a sub-10-nm storage dot, which is located between the channel and the gate. The memories operate at room temperature by charging and discharging one electron in or out of the dot. The charge retention time is up to two days. NIL is shown to be tailored for nanodevice fabrication. By using NIL as a nanolithography tool, the single-electron memory is more feasible for mass production. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]