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Zou L.,China Agricultural University | Gu Z.,Beijing University of Technology | Sun M.,Key Laboratory of Modern Precision Agriculture System Integration Research | Sun M.,Key Laboratory of Agricultural Information Acquisition Technology | Sun M.,China Agricultural University
Toxicological and Environmental Chemistry | Year: 2015

Heavy-metal contamination is a major concern, as excessive heavy metals produce environmental pollution, and the cumulative effects of heavy metals in vivo pose a major threat to human health. There is an urgent need for a rapid, sensitive, and efficient method for detecting heavy metals. Quantum dots (QDs) are in the category of semiconductor nanocrystals whose radii are less than or close to the exciton Bohr radius. QDs possess a potential in the biological and medical fields to function as a new type of fluorescent marker, because of their unique and tunable photophysical properties, which include broad excitation spectrum, narrow emission spectrum, tunable emission wavelengths, and negligible photobleaching. In recent years, QDs made significant progress in quantitative analysis by providing a new approach for determination of chemical content analysis. The aim of this study was to review the research progress of QD detection of heavy metals in water and consider the challenges and future outlook for QD-based sensors for heavy-metal ions. © 2015 Taylor & Francis. Source

Cao M.,China Agricultural University | Cao M.,Key Laboratory of Modern Precision Agriculture System Integration Research | Zhang M.,China Agricultural University | Zhang M.,Key Laboratory of Modern Precision Agriculture System Integration Research | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

In order to meet the requirements of high accuracy position in precision agriculture, using RTK-GPS OEM board and CDMA wireless communication module, the GPS Receiver system based on VRS differential was developed. The experiment results showed that the inner-coincidence accuracy of the system in short-time VRS differential positioning was less than 2 cm (95%) and the accuracy was almost the same in different weather conditions. In dynamic mode, accuracy of the system and Trimble Ag GPS332 were almost the same and both of them could reach to centimeter-level accuracy. The system can meet the requirements of precision agriculture such as automatic navigation for agriculture machine and cropland information collection. Source

Tang J.-B.,China Agricultural University | Li J.-M.,China Agricultural University | Li J.-H.,China Agricultural University | Li J.-H.,Key Laboratory of Modern Precision Agriculture System Integration Research | And 5 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

A total of 96 red wines aged with 3 kinds of methods were included in this study, including 44 wines aged in oak barrel, 26 wines aged in stainless steel tank added with oak chips and 26 wines aged in stainless steel tanks. The infrared spectra of the wines were scanned by Fourier transform infrared spectrometer with attenuated total reflection (ATR) accessories. To classify the 96 different aged wines, discriminant partial least squares (DPLS) method and support vector machine (SVM) method were used to establish models respectively. In order to examine the stability of the discriminant model, modeling was repeated 10 times with two-thirds of samples randomly selected as cross-validation. All the models had high discriminating power with the classification accuracy of the cross-validation and the validation all higher than 90%. These results suggest that the infrared ATR spectroscopy combined with pattern recognition method is a promising tool for discriminating different aging wines. Source

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