[Design and development of the trace Cu2+ optical chemistry sensor].

The present paper proposes an optical chemistry sensor used for real-time detection of trace Cu2+, including the optical perception module and the signal processing module. The optical perception module gives the output of the laser light and excitation of fluorescence. The signal processing module completes optoelectronic conversion and amplification of the weak fluorescence signal as well as data processing and display.

[Effects of nitrogen rates on soil respiration in winter wheat cropping system in semi-arid regions on Loess plateau].

To evaluate effects of nitrogen rates on soil respiration, we measured the diurnal and seasonal dynamic changes and the contents of the soil organic carbon (SOC), soil dissolved organic carbon (DOC), soil microbial biomass carbon (MBC), and total soil nitrogen (TSN) under different growing seasons of winter wheat under the continuous systems from March in 2008 to March in 2009 at Changwu ecological station of the Chinese Academy of Sciences. The experiment consists of five nitrogen rates: 0 (N0), 45 (N45), 90 (N90), 135 (N135), and 180 (N180) kg/hm2. Soil respiration rate significantly enhanced with increasing nitrogen rate ranging from 0 to 90 kg/hm2 and increased little from 90 to 135 kg/hm2, but decreased with increasing nitrogen rate from 135 to 180 kg/hm2.