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Abstract The wind-induced fatigue is the main factor leading to reduction of the bearing capacity of long-span transmission towers. In order to reduce the harm of wind vibration, this paper takes the 500 kV Jiamusi region ISLSTT (in service long span transmission tower) as the research object, and a new kind of vibration reduction system is proposed based on a steel wire rope damping structure, with which the vibration characteristics of ISLSTT is analyzed. Firstly, the layout and components of the new vibration reduction system are described, and the damping performance of which is verified and analyzed by finite element method. Secondly, the nonlinear finite element dynamic simulation model of ISLSTT with the new vibration reduction system is established, and the multi-dimensional fluctuating wind speed time history satisfying Davenport wind speed spectrum is given by harmonic superposition method in the time domain. Based on the Bernoulli theorem, the corresponding time history of wind pressure is obtained, and the random wind load is applied to the finite element model to verify the feasibility and efficient of the new vibration reduction system. Finally, the aero-elastic wind tunnel test model of ISLSTT with the new vibration reduction system is built, and the time history curves of stress and acceleration at key points under different wind directions are obtained. By comparing with the un-damped system, it is demonstrated that the average damping efficiency of this method in the scale of stress and acceleration is 72.88% and 77.17%, respectively. The simulation and wind tunnel test results also demonstrate that the vibration reduction system based on wire rope damping structure can effectively reduce the vibration of ISLSTT caused by the non-uniformity of wind speed. The research results lay a solid foundation for the vibration reduction design of in service long span tower-line system in future.

Abstract Groundwater is an important source of water for human sustenance. The determination of groundwater quality at island sites is an urgent priority in China, but there are lacking systematic reports relating to them. Here, 63 groups of groundwater samples were collected and analyzed of Hainan Island. The groundwater in the study area is weakly alkaline, mainly comprising hard and soft freshwater. The predominant anions and cations are HCO3 −, and Ca2+ and Na+, respectively, and the main water chemistry types are HCO3–Cl–Na and HCO3–Cl–Na–Ca. The chemical evolution of groundwater is mainly affected by water–rock interactions, cation exchange, and human activity. The groundwater is mostly of high quality and, in most areas, is suitable for drinking and irrigation. Contrastingly, the water quality in the west of the island is relatively poor. The spatial distribution of the risk coefficient (HQ) is consistent with the spatial variation in the NO3 − concentrations in the groundwater. Notably, there are unacceptable health risks for different groups of people, with infants having the greatest level of impact, followed by children, teenagers, and adults. This study provides a valuable reference for the development and utilization of groundwater resources, as well as the improvement of aquatic ecological conditions on Hainan Island and other island areas worldwide.

Abstract As the particularly popular green energy, geothermal resources are gradually favored by countries around the world, and the development model centered on geothermal dew point cannot meet the increasing geothermal demand. In this paper, a GIS model combining PCA and AHP is proposed, aiming to select the advantages of geothermal resources at the regional scale and analyze the main influencing indicators. Through the combination of the two methods, both data and empirical can be considered, then the geothermal advantage distribution on the area can be displayed through GIS software images. A multi-index evaluation system is established to qualitatively and quantitatively evaluate the mid-high temperature geothermal resources in Jiangxi Province, and carry out the evaluation of the dominant target areas and the analysis of geothermal impact indicators. The results show that it is divided into 7 geothermal resource potential areas and 38 geothermal advantage targets, and the determination of deep fault is the most critical index of geothermal distribution. This method is suitable for large-scale geothermal research, multi-index and multi-data model analysis and precise positioning of high-quality geothermal resource targets, which can meet the needs of geothermal research at the regional scale.

IL-6 is an important cytokine in the tumour microenvironment, but its role in regulating autophagy in cancer cells is unclear. Here the authors show that IL-6 activates autophagy in colorectal cancer through the interaction between JAK2 and autophagy regulator, BECN1, which leads to chemotherapeutic resistance.