[Representation, analysis and application of landscape graph based on graph theory].

Landscape structure and spatial pattern are the core issues in landscape ecology. The application of graph theory provides a research framework for landscape pattern analysis. Landscape graph based on graph theory is gradually applied to the connectivity modeling of biodiversity conservation and decision support of landscape planning.

Optimization of Process Parameters of Rhamnolipid Treatment of Oily Sludge Based on Response Surface Methodology.

Oily sludge is a hazardous waste. If not handled properly, it can not only pollute the environment but also endanger human health. This study is the first to use a response surface method to optimize the main parameters of rhamnolipid-based recovery of oil from oily sludge.

[Dynamic response and variance of vegetation in China from 1982 to 2015 under the asymmetric rate of temperature fluctuation.].

The impact of global warming on the growth and development of natural vegetation is an important concern worldwide. Based on the data from the vegetation normalization index, daytime temperature (T), nighttime temperature (T), precipitation, and elevation from 1982 to 2015, we examined the day-night warming response of 42 types of natural vegetation in China. The results showed that both the temperature at day and night was significantly increased in the study area, with obvious asymmetry.

[Pollution Characteristics and Health Risk Assessment of Heavy Metals in Wheat Grains Cultivated in Kaifeng Irrigation Area of the Yellow River].

In order to monitor heavy metal pollution in agricultural soils and assess the corresponding health risk in the Yellow River irrigation area, this study applied the Nemero index and the health risk index to evaluate heavy metal pollution in wheat grains and the health risks for residents in the lower reaches of the Yellow River. Four towns in Kaifeng, which are within the lower reaches of the Yellow River, were selected as the study area. The examination of wheat samples revealed that the average contents of Cd, Cr, Pb, Cu, Zn, Ni, and Hg in the wheat grains were 0.

[Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Sediments of Suya Lake].

In order to study the pollution status of heavy metals in sediments of Suya Lake, the concentrations of heavy metals Cu, Cd, Cr, Zn, Pb and Ni in sediments were measured at three locations in the center, middle and periphery of Suya Lake, the content characteristics and the pollution status of heavy metals in the study area were analyzed by the method of geoaccumulation index and potential ecological risk index, and the distribution and interrelation of heavy metals were evaluated by Kriging method and correlation analysis. The results showed that, on average, Zn was the highest, 112.87 mg·kg, followed by Cr, the smallest average of Cd was only 0.

[Study on distribution characteristics and potential ecological risk of soil heavy metals in the Yellow River beach region in Kaifeng City].

The distributions, soil environment status and potential ecological risk of heavy metals were studied in beach soil of returning the cropland into Yellow River beach region in Kaifeng by the Nemerows and Håkansons methods. The results showed that (1) as Among the average contents of the five heavy metals Pb, Cr, Hg, As and Cd, the highest was the average content of Cr, and the lowest was the average content of Pb and Hg. In addition to Hg, the coefficients of variation of other heavy metals were relatively small, indicating that the content of heavy metals was quite different at different sites, and to some extent, relecting that Hg, As and Pb were the major elements polluting the soil, among which, Pb pollution was the pollution with universality.