Chen Y.-J.,Hefei University of Technology |
Deng N.,Hefei University of Technology |
Hu B.,Anhui Sun Create Electronics Co. |
Wang Y.,Hefei University of Technology |
He J.-B.,Hefei University of Technology
Journal of Physical Chemistry B | Year: 2014
Acquisition of data from both in situ spectroscopy detection and online chromatography-like separation is important for studying complex electrochemical reactions. The present work provides an example of combination of thin-layer spectral and electrophoretic electrochemistry, both based on thin-layer electrolysis. Two thin-layer electrochemical cells were used to investigate the electro-oxidation of solid ellagic acid at different potentials, in acidic, physiological, and alkaline buffer media. UV-vis spectra and cyclic voltabsorptograms of the oxidation products were recorded in situ without interference from the solid reactant. Four oxidation products, depending upon the buffer pH and the applied potential, were separated and detected by electrophoretic electrochemistry. The major products possess redox stability, possibly with a diquinonemethide structure. The minor product is considered as an o-quinone derivative with a lactone-ring-opening, which can be reduced or further oxidized at appropriate potentials. A consecutive-parallel reaction mechanism is proposed for the formation of four products of ellagic acid in different pH media, which enriches the knowledge about the oxidation pathway and antioxidant property of this biologically active polyphenol compound. © 2014 American Chemical Society.
Liu L.,Chinese Academy of Meteorological Sciences |
Hu Z.,Chinese Academy of Meteorological Sciences |
Fang W.,Anhui Sun Create Electronics Co. |
Ge R.,Chinese Academy of Meteorological Sciences |
And 2 more authors.
Acta Meteorologica Sinica | Year: 2010
A C-band mobile Polarimetrie radar with simultaneous horizontal and vertical transmission was built in the State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences. It was used in heavy rainfall and typhoon observations in 2008. It is well-known that radar calibration is essential and critical to high quality radar data and products. In this paper, the test and weather signals were used in calibration of reflectivity Zn, differential reflectivity ZOR, and differential phase ΦDP- Noise effects on correlation coefficient ρHV at low signal-noise-ratio (SNR) were analyzed. The Polarimetrie radar data for a heavy rain and a snow event were inspected to evaluate the performance of the calibration method and radar data quality, and S-band Doppler radar data were used to validate the reflectivity data quality collected by the Polarimetrie radar. The results show that the Polarimetrie and S-band Doppler radars have observed comparable reflectivity values and a similar structure of a heavy rainfall case at middle and low levels. The mismatch of two receivers produce obvious ZDR biases, which were verified by the radar data observed at vertical incidence. The ZDR correction improved the radar data quality. The usage range for ρHV was defined. Application of the calibration method introduced in this paper can reduce the system biases caused by the difference of horizontal (H) and vertical (V) channels. After the calibration and correction, the Polarimetrie parameters observed by the Polarimetrie radar could be used in further relevant researches.
Zhou H.,University of Electronic Science and Technology of China |
Zhou H.,Anhui Sun Create Electronics Co. |
Guo L.,University of Electronic Science and Technology of China
Journal of Electronics | Year: 2010
Mode S Second Surveillance Radar (SSR) is very important means for Air Traffic Control (ATC) now and future, all the responding data which the radar receives need parity processing. Bit and confidence declaration is an vital step before error detection and error correction. Based on the commonly used baseline multi-sample algorithm, different conditions are presented and analyzed, the conditions under which error happens are pointed out, and the algorithm in which two statistical variables are added to avoid false declaration. In addition, the moving average method is used to preprocess the sampled data, so as to reduce the influence of noise. The merits the baseline multi-sample technique owes are preserved, and the added computation is small. The declaration veracity is improved, and consequently makes error detection and error correction be facilitated successfully. © 2010 Science Press, Institute of Electronics, CAS and Springer-Verlag Berlin Heidelberg.