Efficient channelized technology based on filter banks

With the appearance of novel radar signal with low intercept probability, the bandwidth of radar receiver is wider and wider. Wideband digital receiver becomes a research hotspot in the field of communication, radar and electronic reconnaissance, etc. As one of wideband digital receiver systems, digital channelized receiver has become a research emphasis due to the characteristics of full probability receiving and processing multiple signals. Digital channelized technology and signal sampling theory are deeply studied and an efficient channelized model is derived based on filter banks. The correctness of the model is verified by computer simulation The model has less computation compared with the traditional model, which is suitable for engineering application

Innovation Renaissance China has pledged to channel its efforts into breaking new ground in science and technology in the coming years

As 2006 unfolds, China plans to transform its economic development mode to usher in a new era of innovation. The National Conference on Science and Technology, held this month, provides a fresh impetus to that endeavor. The strategy of "enhancing

Ecological wetland paradigm drives water source improvement in the stream network of Yangtze River Delta

Jiaxing created a precedent using bypass riparian marshes to purify micro-polluted water sources in China.Pond-wetland complex with constructed root channel technology becomes a paradigm which can be analogized as"human-body wetland model"based on bionics or biomimetics.Heterogeneous plant-bed/ditch system with highly active land/water ecotone interfaces,especially meandering boundaries,breeds many biochemical reactions"living areas".Optimization of hydraulic regulation promotes redox environment alternations and wetland treatment efficiency.Here we reported a series of upgrades and performances in Guanjinggang wetland after the Shijiuyang prototype.Morphological reform of plant-bed/ditch system played a vital role.Spatially root channel zone was main force of wetland purification,and temporally the treatment effect was higher in low-temperature seasons indicating non-temperature dependent mechanisms worked.Water pollution comprehensive index improved steadily from IV to III,and comprehensive pollution load was reduced by ca.40%–60%.Comprehensive evaluation function value further showed the gradients purification effect of the upgraded wetland.Ecological wetlands ameliorated source water quality,and reduced drinking water treatment reagents,thereby bringing about economic benefits.Through wetlands operation,people can see how the micro-polluted surface water becomes clear and clean,so promoting a significant social benefit.As a viable component of urban green space,wetlands could beautify regional eco-environment,freshen the air,increase urban ecological taste,and enhance the eco-environmental protection publicity.Thus,the multifunctional service values and indirect benefits are substantial.Jiaxing ecological wetlands provide a typical paradigm for water pollution remediation in developing countries and plays a leading role in technology engineering radiation effect.

Performance of pond–wetland complexes as a preliminary processor of drinking water sources

Shijiuyang Constructed Wetland（110 hm^2） is a drinking water source treatment wetland with primary structural units of ponds and plant-bed/ditch systems. The wetland can process about 250,000 tonnes of source water in the Xincheng River every day and supplies raw water for Shijiuyang Drinking Water Plant. Daily data for 28 months indicated that the major water quality indexes of source water had been improved by one grade. The percentage increase for dissolved oxygen and the removal rates of ammonia nitrogen, iron and manganese were 73.63%, 38.86%, 35.64%, and 22.14% respectively. The treatment performance weight of ponds and plant-bed/ditch systems was roughly equal but they treated different pollutants preferentially. Most water quality indexes had better treatment efficacy with increasing temperature and inlet concentrations. These results revealed that the pond–wetland complexes exhibited strong buffering capacity for source water quality improvement. The treatment cost of Shijiuyang Drinking Water Plant was reduced by about 30.3%. Regional rainfall significantly determined the external river water levels and adversely deteriorated the inlet water quality, thus suggesting that the ＂hidden＂ diffuse pollution in the multitudinous stream branches as well as their catchments should be the controlling emphases for river source water protection in the future. The combination of pond and plant-bed/ditch systems provides a successful paradigm for drinking water source pretreatment. Three other drinking water source treatment wetlands with ponds and plant-bed/ditch systems are in operation or construction in the stream networks of the Yangtze River Delta and more people will be benefited.