Underground space creation and energy extraction, which induce unloading on rock fractures, commonly occur in various rock engineering projects, and rock engineering projects are subjected to high temperatures with in...Underground space creation and energy extraction, which induce unloading on rock fractures, commonly occur in various rock engineering projects, and rock engineering projects are subjected to high temperatures with increasing depth. Fluid flow behavior of rock fractures is a critical issue in many subsurface rock engineering projects. Previous studies have extensively considered permeability evolution in rock fractures under loading phase, whereas changes in fracture permeability under unloading phase have not been fully understood. To examine the unloading-induced changes in fracture permeability under different temperatures, we performed water flow-through tests on fractured rock samples subjected to decreasing confining pressures and different temperatures. The experimental results show that the permeability of fracture increases with unloading of confining pressure but decreases with loading-unloading cycles. Temperature may affect fracture permeability when it is higher than a certain threshold. An empirical model of fracture hydraulic aperture including two material parameters of initial normal stiffness and maximum normal closure can well describe the permeability changes in rough rock fracture subjected to loading-unloading cycles and heating. A coupled thermo-mechanical model considering asperity damage is finally used to understand the influences of stress paths and temperatures on fracture permeability.展开更多
Predicting the stages of cancer accurately is crucial for effective treatment planning. In this study, we aimed to develop a model using gene expression data and XGBoost (eXtreme Gradient Boosting) that include clinic...Predicting the stages of cancer accurately is crucial for effective treatment planning. In this study, we aimed to develop a model using gene expression data and XGBoost (eXtreme Gradient Boosting) that include clinical and demographic variables to predict specific lung cancer stages in patients. By conducting the feature selection using the Wilcoxon Rank Test, we picked the most impactful genes associated with lung cancer stage prediction. Our model achieved an overall accuracy of 82% in classifying lung cancer stages according to patients’ gene expression data. These findings demonstrate the potential of gene expression analysis and machine learning techniques in improving the accuracy of lung cancer stage prediction, aiding in personalized treatment decisions.展开更多
Traditional food packaging films made of plastic have caused serious damage to the environment.Chitosan film is a potential substitute but it is weak in antioxidant activity.In this study,the extract and chitosan from...Traditional food packaging films made of plastic have caused serious damage to the environment.Chitosan film is a potential substitute but it is weak in antioxidant activity.In this study,the extract and chitosan from American cockroach were combined to produce a new environment-friendly chitosan film for food packaging.The chitosan film was easily degraded by water,avoiding accumulation in the environment.The addition of American cockroach extract improved the antioxidant activity of the chitosan film(up to 50 times higher than that of pure chitosan film when considering reducing capacity)and did not weaken its efficient antibacterial activity.In practical application,the packaged food was protected by the chitosan film from fast decay and oxidation for 15 days and 48 h,respectively.These results suggested that the new chitosan film possessed the potential for food packaging and improved the value of American cockroach.展开更多
基金supported by the National Natural Science Foun-dation of China(Grant Nos.U2067203 and 42277140)Tsinghua University Initiative Scientific Research Program(Grant No.2022Z11QYJ006).
文摘Underground space creation and energy extraction, which induce unloading on rock fractures, commonly occur in various rock engineering projects, and rock engineering projects are subjected to high temperatures with increasing depth. Fluid flow behavior of rock fractures is a critical issue in many subsurface rock engineering projects. Previous studies have extensively considered permeability evolution in rock fractures under loading phase, whereas changes in fracture permeability under unloading phase have not been fully understood. To examine the unloading-induced changes in fracture permeability under different temperatures, we performed water flow-through tests on fractured rock samples subjected to decreasing confining pressures and different temperatures. The experimental results show that the permeability of fracture increases with unloading of confining pressure but decreases with loading-unloading cycles. Temperature may affect fracture permeability when it is higher than a certain threshold. An empirical model of fracture hydraulic aperture including two material parameters of initial normal stiffness and maximum normal closure can well describe the permeability changes in rough rock fracture subjected to loading-unloading cycles and heating. A coupled thermo-mechanical model considering asperity damage is finally used to understand the influences of stress paths and temperatures on fracture permeability.
文摘Predicting the stages of cancer accurately is crucial for effective treatment planning. In this study, we aimed to develop a model using gene expression data and XGBoost (eXtreme Gradient Boosting) that include clinical and demographic variables to predict specific lung cancer stages in patients. By conducting the feature selection using the Wilcoxon Rank Test, we picked the most impactful genes associated with lung cancer stage prediction. Our model achieved an overall accuracy of 82% in classifying lung cancer stages according to patients’ gene expression data. These findings demonstrate the potential of gene expression analysis and machine learning techniques in improving the accuracy of lung cancer stage prediction, aiding in personalized treatment decisions.
基金supported by the National Natural Science Foundation of China(Nos.31830084,32070466&31970440)“the Fundamental Research Funds for the Central Universities”,Nankai University(Nos.96172158,96173250&91822294).
文摘Traditional food packaging films made of plastic have caused serious damage to the environment.Chitosan film is a potential substitute but it is weak in antioxidant activity.In this study,the extract and chitosan from American cockroach were combined to produce a new environment-friendly chitosan film for food packaging.The chitosan film was easily degraded by water,avoiding accumulation in the environment.The addition of American cockroach extract improved the antioxidant activity of the chitosan film(up to 50 times higher than that of pure chitosan film when considering reducing capacity)and did not weaken its efficient antibacterial activity.In practical application,the packaged food was protected by the chitosan film from fast decay and oxidation for 15 days and 48 h,respectively.These results suggested that the new chitosan film possessed the potential for food packaging and improved the value of American cockroach.
