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We propose and study GaAs/Al25Ga75As terahertz frequency quantum cascade lasers in which mid-infrared radiation is used as a coherent drive for enhancing the terahertz gain.
We have studied spectral diffusion of excitons in GaAs quantum wells using two-dimensional coherent spectroscopy. Localized and delocalized excitons exhibit distinct spectral diffusion characteristics. These results cannot be explained in the strong redistribution approximation.
This study aims to probe the effects of teachers' and peers' communication style and quality on adolescents' cognitive and emotional learning by questionnaires and regression analysis. The relations between impact of emotional learning and academic learning are examined; and the intermediate variable of learning performance is found out to be learning motivation. Results show that students' perception...
The wavelength limit (λc) of detection in a conventional photodetector is limited to a characteristic energy (Δ) through the relationship: λc = hc/Δ, where Δ also determines the detector noise (dark current) and hence its performance such as the operating temperature. Here, we report an infrared photodetector with an extended operating range (responding beyond the standard spectral threshold) based...
We report photovoltaic infrared detectors based on graded-barrier asymmetric heterostructures. Detectors with a single period structure showed room temperature operation with a zero-response threshold of ∼4 µm, and a comparable detectivity to 30-period photoconductive split-off detectors reported previously. An additional long-wavelength response peak of up to 8 µm was also observed when the operating...
We report the 3rd year's progress of an internet based crossover robot remote control competition which is an international cooperative educational project among Japan, China, Thailand, and Taiwan. In 2009 we proposed a new competition model called “Cargo loading via internet based cooperation” in which a locally controlled humanoid robot and a wheeled mobile robot under remote control cooperate with...
Taken the relief maps, MSS images, TM images, ETM images and CBERS images as basic data sources, this paper studied on the dynamic of lakes in Tibetan Plateau since 1960's using RS and GIS technique. The results showed that the increasing area of lakes in Tibetan Plateau in last 50 years is 5760 km2. The change can be divided into two phases: the lake trended to shrink from 1960's to the imddle of...
This paper assesses the transient operation of a 33 kV distribution network in islanded operation consisting of different type and size of loads and distributed (mainly renewable) generators. The generators considered include synchronous generator representing the combined heat and power unit, fixed speed induction generator, doubly fed induction generator and power electronic connected photovoltaic...
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