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In this study, a homogeneous polysaccharide fraction was extracted and purified from the rhizome of Polygonatum sibiricum, its physicochemical properties and protective effect against oxidative damage were analyzed, and its potential protective mechanism was initially explored. The homogeneous polysaccharide (PSP) was obtained by water extraction, alcohol precipitation, and separation on DEAE-52 cellulose and Sephadex G-100 columns. The phenol sulfate method, m-hydroxybiphenyl method, high performance gel permeation chromatography and Fourier infrared spectroscopy were used to analyze the physicochemical properties of PSP. The in vivo antioxidant effects of PSP were investigated in a mouse model of D-galactose induced oxidative damage. The results showed that the carbohydrate content of PSP was 94.42%±14.73% and its molecular weight was 5566.41 Da. PSP was also found to contain β-type furan or pyran fructose, as well as longer branched chains with more branches. Compared with the model group, the levels of SOD, GSH-Px and T-AOC significantly increased (P

In order to ensure the reliable operation of oil transmission stations and improve the lightning protection performance of their power supply lines, the lightning accidents occurred to power supply lines in the Anshun Station in the southern mountainous area of China during 2018 to 2020 were counted by category, and comprehensive analysis was performed for the lightning accidents. On this basis, the poles and towers requiring transformation for lightning protection were determined by considering the four influencing factors of line corridor, i.e., ground flash density, topography, grounding resistance of poles and towers, and lightning withstand level. In view of the lightning protection measures of improving the insulation level, reducing the grounding resistance, and installing lightning arresters, analysis was conducted for the poles and towers one by one, and transformation measures for differentiated lightning protection were put forward on the basis of ensuring the lightning protection capability, with reference to the on-site construction of the lines and the economic conditions of line transformation. Upon completion of the line transformation, the trip rate and equipment damage rate caused by lightning are significantly reduced, which proves the scientificity and effectiveness of the transformation plan.

Due to the effect of climate changes and human activities, groundwater over-exploitation and aquifer depletion have become global issues of concern. Artificial recharge of groundwater through a river has been paid more attention among a variety of artificial intervention measures. It is found that not all rivers or river reaches are suitable for artificial recharge of groundwater owing to the limitations of recharge potential by infiltration and storage capacity of the vadose zone. At present, there is still a lack of widely accepted suitability assessment methods. In this study, the Yongding River in the Beijing Plain section and the underlying aquifer are taken as the study area and the case study is carried out. Moreover, the measured data are used to verify the results. The suitability assessment model (LMBGITSC model) constructed by the index system method includes eight indexes: land use types of riverbed, sediment types of riverbed, channel width, channel topographic slope, medium types of the vadose zone, thickness of the vadose zone, specific yield of the vadose zone and horizontal permeability of the vadose zone. The results show that the suitability of groundwater recharge in the Yongding River changes from good degree to medium degree along the river flow direction (except the reaches carried out anti-seepage engineering), presenting a "step-type" evolution law. The proposed method is of good applicability and can also provide reference for similar regions.

Interaction between surface water and groundwater has always been a hot topic in hydrogeological researches. Previous studies focused on the hyporheic zone of rivers, but the hypolentic zone of lakes with relatively static water bodies was seldom examined. The Baiyangdian Wetlands is taken as a pilot area in this study, and a monitoring system of water table and temperature is set up. The vertical interaction fluxes between surface water and groundwater is quantified by using a heat tracing method. According to the Darcy’s Law, the vertical coefficient of permeability is calculated inversely. Based on the heat tracing method and the Darcy’s Law, a way of quantifying vertical interaction between surface water and groundwater is summarized. The results show that infiltration from surface water to groundwater around the banks of the Baiyangdian Wetlands is dominant in the interaction procedure. The total infiltration velocity from surface water to groundwater during the monitoring period ranges from 0.2 to 1.1 cm/d, and the vertical hydraulic conductivity, from 0.038 to 0.912 m/d. The conclusions in this paper can provide data support for strategy of water diversion and protection of eco-environment in the Baiyangdian Wetlands.