Rock failure phenomena,such as rockburst,slabbing(or spalling) and zonal disintegration,related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining.Currently,the...Rock failure phenomena,such as rockburst,slabbing(or spalling) and zonal disintegration,related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining.Currently,the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward.In this study,new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced.Two types of coupled loading modes,i.e.'critical static stress + slight disturbance' and 'elastic static stress + impact disturbance',are proposed,and associated test devices are developed.Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory,and the rockburst mechanism and related criteria are demonstrated.The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold,and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion.Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density.In addition,we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass,which can efficiently and accurately locate the rock failure in hard rock mines.Also,a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced.展开更多
Insulinomas,the most common cause of hypoglycemia related to endogenous hyperinsulinism,occur in 1-4 people per million of the general population.Common autonomic symptoms of insulinoma include diaphroresis,tremor,and...Insulinomas,the most common cause of hypoglycemia related to endogenous hyperinsulinism,occur in 1-4 people per million of the general population.Common autonomic symptoms of insulinoma include diaphroresis,tremor,and palpitations,whereas neuroglycopenenic symptoms include confusion,behavioural changes,personality changes,visual disturbances,seizure,and coma.Diagnosis of suspected cases is based on standard endocrine tests,especially the prolonged fasting test.Non-invasive imaging procedures,such as computed tomography and magnetic resonance imaging,are used when a diagnosis of insulinoma has been made to localize the source of pathological insulin secretion.Invasive modalities,such as endoscopic ultrasonography and arterial stimulation venous sampling,are highly accurate in the preoperative localization of insulinomas and have frequently been shown to be superior to noninvasive localization techniques.The range of techniques available for the localization of insulinomas means thatblind resection can be avoided.Intraoperative manual palpation of the pancreas by an experienced surgeon and intraoperative ultrasonography are both sensitive methods with which to finalize the location of insulinomas.A high proportion of patients with insulinomas can be cured with surgery.In patients with malignant insulinomas,an aggressive medical approach,including extended pancreatic resection,liver resection,liver transplantation,chemoembolization,or radiofrequency ablation,is recommended to improve both survival and quality of life.In patients with unresectable or uncontrollable insulinomas,such as malignant insulinoma of the pancreas,several techniques should be considered,including administration of ocreotide and/or continuous glucose monitoring,to prevent hypoglycemic episodes and to improve quality of life.展开更多
基金jointly supported by the State Key Research Development Program of China (Grant No.2016YFC0600706)the National Natural Science Foundation of China (Grant Nos.41630642 and 11472311)
文摘Rock failure phenomena,such as rockburst,slabbing(or spalling) and zonal disintegration,related to deep underground excavation of hard rocks are frequently reported and pose a great threat to deep mining.Currently,the explanation for these failure phenomena using existing dynamic or static rock mechanics theory is not straightforward.In this study,new theory and testing method for deep underground rock mass under coupled static-dynamic loading are introduced.Two types of coupled loading modes,i.e.'critical static stress + slight disturbance' and 'elastic static stress + impact disturbance',are proposed,and associated test devices are developed.Rockburst phenomena of hard rocks under coupled static-dynamic loading are successfully reproduced in the laboratory,and the rockburst mechanism and related criteria are demonstrated.The results of true triaxial unloading compression tests on granite and red sandstone indicate that the unloading can induce slabbing when the confining pressure exceeds a certain threshold,and the slabbing failure strength is lower than the shear failure strength according to the conventional Mohr-Column criterion.Numerical results indicate that the rock unloading failure response under different in situ stresses and unloading rates can be characterized by an equivalent strain energy density.In addition,we present a new microseismic source location method without premeasuring the sound wave velocity in rock mass,which can efficiently and accurately locate the rock failure in hard rock mines.Also,a new idea for deep hard rock mining using a non-explosive continuous mining method is briefly introduced.
基金Supported by Kochi Organization for Medical Reformation and Renewal Fundthe support of SatoshiIto and Kazuhiro Hanazaki(Kochi Medical School)
文摘Insulinomas,the most common cause of hypoglycemia related to endogenous hyperinsulinism,occur in 1-4 people per million of the general population.Common autonomic symptoms of insulinoma include diaphroresis,tremor,and palpitations,whereas neuroglycopenenic symptoms include confusion,behavioural changes,personality changes,visual disturbances,seizure,and coma.Diagnosis of suspected cases is based on standard endocrine tests,especially the prolonged fasting test.Non-invasive imaging procedures,such as computed tomography and magnetic resonance imaging,are used when a diagnosis of insulinoma has been made to localize the source of pathological insulin secretion.Invasive modalities,such as endoscopic ultrasonography and arterial stimulation venous sampling,are highly accurate in the preoperative localization of insulinomas and have frequently been shown to be superior to noninvasive localization techniques.The range of techniques available for the localization of insulinomas means thatblind resection can be avoided.Intraoperative manual palpation of the pancreas by an experienced surgeon and intraoperative ultrasonography are both sensitive methods with which to finalize the location of insulinomas.A high proportion of patients with insulinomas can be cured with surgery.In patients with malignant insulinomas,an aggressive medical approach,including extended pancreatic resection,liver resection,liver transplantation,chemoembolization,or radiofrequency ablation,is recommended to improve both survival and quality of life.In patients with unresectable or uncontrollable insulinomas,such as malignant insulinoma of the pancreas,several techniques should be considered,including administration of ocreotide and/or continuous glucose monitoring,to prevent hypoglycemic episodes and to improve quality of life.
