[Differential geometry expression and analysis of regionalized variables of typical pollutants concentration in terrestrial environment].

Based on the basic concepts of differential geometry in analyzing environmental data and establishing related models, the methodology for differential geometry expression and analysis of pollutants concentration in terrestrial environment was presented. As a kind of regionalized variables, the spatial distribution pattern of the pollutants concentration was transformed into 3-dimension form, and fitted with conicoid. This approach made it possible to analyze the quantitative relationships between the regionalized variables and their spatial structural attributes. For illustration purpose, several sorts of typical space fabrics, such as convexity, concavity, ridge, ravine, saddle, and slope, were calculated and characterized. It was suggested that this approach was feasible for analyzing the regionalized variables of pollutants concentration in terrestrial environment.

[Revaluation of soil heavy metals pollution in Zhangshi irrigation area of Shenyang and analysis of Cd forms in soil].

This paper revaluated the situation of cadmium (Cd) pollution in rice field soils of Zhangshi irrigation area in Shenyang. The results indicated that the soil Cd pollution of test area was still quite serious. The Cd content in brown rice samples ranged from 0.435 to 0.855 mg x kg(-1), which exceeded the national criteria for food sanitation in China, and increased by 335%-755% compared with that 20 years ago. Brown rice Cd had a significant negative correlation with soil pH, and a positive correlation with soil available Cd. The decrease of soil pH induced more soil Cd transformed into available Cd which occupied 22.8%-52.0% of the total Cd and was easy to be absorbed by rice plant, inducing the Cd in brown rice exceeded national criteria. The pollutant Cd could transfer along with surface runoff, ground water and flying dust, making the pollution extend gradually.

[Library search of UV spectra of organic environmental pollutants by temperature-constrained cascade-correlation networks].

A temperature-constrained cascade-correlation network (TCCCN) was used to identify ultraviolet (UV) spectra of organic environmental pollutants. Library search for UV spectra is more difficult than that for infrared (IR) spectra, because the UV spectra overlap more severely than IR spectra. Besides, drift and noise in the measurement will have significant effect on UV library spectra search. Therefore, neural networks with fuzzy output should be a better alternative for the library search. The TCCCN is different from the commonly used BP networks in architecture. The processing units in the TCCCN are connected in a cascade mode, and a temperature constraint is introduced. Therefore, the TCCCN can reduce overtraining and fast training speed. TCCCN was used for library search of UV spectra in the present work and the effects of network parameters and noise were investigated. Results showed that better results were obtained with the TCCCN than with conventional correlation method.