31 research outputs found
Abrupt drainage basin reorganization following a Pleistocene river capture
River capture is a dramatic natural process of internal competition through which mountainous landscapes evolve and respond to perturbations in tectonics and climate. River capture may occur when one river network grows at the expense of another, resulting in a victor that steals the neighboring headwaters. While river capture occurs regularly in numerical models, field observations are rare. Here we document a late Pleistocene river capture in the Yimeng Mountains, China that abruptly shifted 25 km^2 of drainage area from one catchment to another. River terraces and imbricated cobbles indicate that the main channel incised 27 m into granitic bedrock within 80 kyr, following the capture event, and upstream propagating knickpoints and waterfalls reversed the flow direction of a major river. Topographic analysis shows that the capture shifted the river basins far from topographic equilibrium, and active divide migration is propagating the effects of the capture throughout the landscape
Self-Lubricating Polytetrafluoroethylene/Polyimide Blends Reinforced with Zinc Oxide Nanoparticles
ZnO nanoparticle reinforced polytetrafluoroethylene/polyimide (PTFE/PI) nanocomposites were prepared and their corresponding tribological and mechanical properties were studied in this work. The influences of ZnO loading, sliding load, and velocity on the tribological properties of ZnO/PTFE/PI nanocomposites were systematically investigated. Results reveal that nanocomposites reinforced with 3 wt% ZnO exhibit the optimal tribological and mechanical properties. Specifically, the wear loss decreased by 20% after incorporating 3 wt% ZnO compared to unfilled PTFE/PI. Meanwhile, the impact strength, tensile strength, and elongation-at-break of 3 wt% ZnO/PTFE/PI nanocomposite are enhanced by 85, 5, and 10% compared to pure PTFE/PI blend. Microstructure investigation reveals that ZnO nanoparticles facilitate the formation of continuous, uniform, and smooth transfer film and thus reduce the adhesive wear of PTFE/PI
Abrupt drainage basin reorganization following a Pleistocene river capture
River capture is a dramatic natural process of internal competition through which mountainous landscapes evolve and respond to perturbations in tectonics and climate. River capture may occur when one river network grows at the expense of another, resulting in a victor that steals the neighboring headwaters. While river capture occurs regularly in numerical models, field observations are rare. Here we document a late Pleistocene river capture in the Yimeng Mountains, China that abruptly shifted 25 km^2 of drainage area from one catchment to another. River terraces and imbricated cobbles indicate that the main channel incised 27 m into granitic bedrock within 80 kyr, following the capture event, and upstream propagating knickpoints and waterfalls reversed the flow direction of a major river. Topographic analysis shows that the capture shifted the river basins far from topographic equilibrium, and active divide migration is propagating the effects of the capture throughout the landscape
Intelligent inspection robot system for return air roadway in Zhangjiamao Coal Mine
In order to solve the problem of manual inspection of return air roadway in Zhangjiamao Coal Mine, an intelligent inspection robot system of return air roadway with the functions of equipment inspection and environment detection is designed. Through the detailed research and design of the inspection robot, drive execution, damper control, communication network construction, energy supply and other subsystems in the system, it can walk autonomously and locate accurately in the complex unstructured environment of coal mine, and collect the image, sound and environmental parameters of the inspection site in real time by carrying a variety of sensors. It can realize the functions of working condition detection, deformation detection, gas concentration and other environmental perception, data processing and early warning, and human-computer interaction. The practical application results show that the inspection robot system can replace the manual inspection, realize the detection, early warning, judgment and analysis of return air roadway, reduce the workload and safety risk of inspection personnel, simplify the complexity of inspection task, reduce the number of inspection personnel, and achieve “reducing personnel and increasing efficiency”
Comprehensive Evaluation of Wheat Varieties in Southern Shandong Province by DTOPSIS Based on Entropy Weighting
[Objectives] To screen a new wheat variety suitable for planting in southern Shandong Province. [Methods] The DTOPSIS based on entropy weighting was used to comprehensively evaluate 9 traits of 19 wheat varieties planted in southern Shandong Province. [Results] The weight of each indicator from low to high was growth period < yield < bulk density < plant height < effective panicle < basic seedling < 1 000-grain weight < heading rate < number of grains per panicle. The Ci value of 6 varieties were greater than 0.5, specifically, 0.922 1 for Shannong HH126, 0.868 for DK171, 0.851 5 for Hemai 179, 0.719 6 for Feida 6, 0.696 7 for Jinlai 36 and 0.523 2 for Yannong 301. [Conclusions] The comprehensive traits of these six wheat varieties are good, and they are suitable for planting in southern Shandong Province
Comprehensive Evaluation of Wheat Varieties in Southern Shandong Province by DTOPSIS Based on Entropy Weighting
[Objectives] To screen a new wheat variety suitable for planting in southern Shandong Province. [Methods] The DTOPSIS based on entropy weighting was used to comprehensively evaluate 9 traits of 19 wheat varieties planted in southern Shandong Province. [Results] The weight of each indicator from low to high was growth period < yield < bulk density < plant height < effective panicle < basic seedling < 1 000-grain weight < heading rate < number of grains per panicle. The Ci value of 6 varieties were greater than 0.5, specifically, 0.922 1 for Shannong HH126, 0.868 for DK171, 0.851 5 for Hemai 179, 0.719 6 for Feida 6, 0.696 7 for Jinlai 36 and 0.523 2 for Yannong 301. [Conclusions] The comprehensive traits of these six wheat varieties are good, and they are suitable for planting in southern Shandong Province
PEDF Inhibits the Activation of NLRP3 Inflammasome in Hypoxia Cardiomyocytes through PEDF Receptor/Phospholipase A2
The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome has been linked to sterile inflammation, which is involved in ischemic injury in myocardial cells. Pigment epithelium-derived factor (PEDF) is a multifunctional secreted glycoprotein with many biological activities, such as anti-inflammatory, antioxidant and anti-angiogenic properties. However, it is not known whether and how PEDF acts to regulate the activation of the NLRP3 inflammasome in cardiomyocytes. In the present study, we used the neonatal cardiomyocytes models of ischemia-like conditions to evaluate the mitochondrial fission and the activation of the NLRP3 inflammasome. We also determined the mechanism by which PEDF inhibits hypoxia-induced activation of the NLRP3 inflammasome. We found that PEDF decreased the activation of the NLRP3 inflammasome in neonatal cardiomyocytes through pigment epithelial-derived factor receptor/calcium-independent phospholipase A2 (PEDFR/iPLA2). Meanwhile, PEDF reduced Drp1-induced mitochondrial fission and mitochondrial fission-induced mitochondrial DNA (mtDNA), as well as mitochondrial reactive oxygen species (mtROS) release into cytosol through PEDFR/iPLA2. We also found that PEDF inhibited mitochondrial fission-induced NLRP3 inflammasome activation. Furthermore, previous research has found that endogenous cytosolic mtDNA and mtROS can serve as activators of NLRP3 inflammasome activity. Therefore, we hypothesized that PEDF can protect against hypoxia-induced activation of the NLRP3 inflammasome by inhibiting mitochondrial fission though PEDFR/iPLA2