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In this paper, an effective identification method of wavelength variable selection to rapidly discriminate the grape seed oil adulteration by near-infrared (NIR) spectroscopy is investigated. The extreme learning machine (ELM) is employed to build a stable and accurate model, and a firefly algorithm combined with a successive projections algorithm (FA-SPA) is developed to eliminate redundant wavelengths (The model used throughout is called FA-SPA-ELM). The comparison among different models--the partial least squares discriminant analysis (PLS-DA) model, the support vector machine (SVM) model, the least squares support vector machine (LS-SVM), and the FA-SPA-ELM model--demonstrates that the wavelength number of the FA-SPA model can be effectively reduced with a wavelength variable of 17, and the model of FA-SPA-ELM presents the excellent predictive capability. The experimental results show that the proposed novel method could be used to identify adulterated grape seed oil quickly, effectively, and nondestructively. [ABSTRACT FROM AUTHOR]

The relationship between the leaf nitrogen content (LNC) and hyperspectral remote sensing imagery (HYP) was determined to construct an estimation model of the LNC of drip-irrigated sugar beets, aiming to provide supports for the in-time monitoring of sugar beet growth and nitrogen management in arid areas. In this study, a field hyperspectrometer was used to collect the leaf reflectance at the 350-2500 nm for each treatment on the 65th, 85th, 104th, 124th, and 140th day after emergence, and the LNC and leaf chlorophyll content (CHL) of sugar beets were also determined. The spectral characteristic parameters were selected to construct the vegetation indices. The LNC estimation model using HYP as the independent variable (HYP-LNC), and that using CHL and HYP as the independent variables (HYP-CHL-LNC), were compared. The results shows that the HYP-CHL-LNC models had a better linear relationship and a higher fitting accuracy than the HYP-LNC models. [ABSTRACT FROM AUTHOR]

This article describes an approach to extend the bandwidth of power amplifiers (PA) designed using resistive-reactive series of continuous class F modes (SCFM). By introducing third harmonic loads to the resistive-reactive SCFM PA, the overlap between the fundamental and harmonic impedances is solved and the operating bandwidth extended. Using this approach, a 0.5 to 2.3 GHz high efficiency PA was designed, with experimental results achieving 10 W output power and 59 to 79 percent drain efficiency from 0.5 to 2.3 GHz. [ABSTRACT FROM AUTHOR]