The transistor action with negative differential resistance (NDR) of a nanometer-thick metal (CoSi2)/insulator (CaF2) resonant tunneling transistor is discussed for two transistor structures. These transistors are composed of metal-insulator (M-I) heterostructures with two metallic (CoSi2) quantum wells and three insulator (CaF2) barriers grown on an n-Si (lll) substrate. One of the two structures has the base terminal connected to one of the quantum wells next to the collector, and the other, to one next to the emitter. Although base resistance is high maybe due to the damage caused during the fabrication process, the two transistors show different characteristics, as expected theoretically. Transfer efficiency α (= IC/IE) close to unity was obtained at 77 K for electrons through the resonant levels in M-I heterostructures.

Doppler lidar (LIght Detection And Ranging) can provide accurate wind velocity vector estimates by processing the time delay and Doppler spectrum of received signals. This system is essential for real-time wind monitoring to assist aircraft taking off and landing. Considering the difficulty of calibration and cost, a single Doppler lidar model is more attractive and practical than a multiple lidar model. In general, it is impossible to estimate two or three dimensional wind vectors from a single lidar model without any prior information, because lidar directly observes only a 1-dimensional (radial direction) velocity component of wind. Although the conventional VAD (Velocity Azimuth Display) and VVP (Velocity Volume Processing) methods have been developed for single lidar model, both of them are inaccurate in the presence of local air turbulence. This paper proposes an accurate wind velocity estimation method based on a parametric approach using typical turbulence models such as tornado, micro-burst and gust front. The results from numerical simulation demonstrate that the proposed method remarkably enhances the accuracy for wind velocity estimation in the assumed modeled turbulence cases, compared with that obtained by the VAD or other conventional method.