To study the relationship between incidence and time course of traumatic intracerebral hematoma enlargement and that between hematoma irregular rate (IR) and hematoma enlargement after brain injury.Methods After brain...To study the relationship between incidence and time course of traumatic intracerebral hematoma enlargement and that between hematoma irregular rate (IR) and hematoma enlargement after brain injury.Methods After brain injury,164 cases with traumatic supratentorial intracerebral hematoma were examined by cranial CT scan within 72 hours thereafter reexamined 120 hours there after so as to compare the hematoma volumes (V1 and V2) and analyze the relation between hematoma IR and hematoma enlargement.Results After brain injury,enlargement of hematoma was confirmed in 70 cases (42.7%),in which the cutpoint for hematoma enlargement was determined as V2/V1=1.45 by using receiver operating characteristic curves (ROC).Hematoma IR had positive correlation with hematoma enlargement (r=0.857,P<0.01).Conclusion Since the incidence of traumatic hematoma enlargement is high,we can tell the possibility of hematoma enlargement based on hematoma IR in order to make a timely reexamination of CT scan and apply active treatments.7 refs,1 tab.展开更多
In Pelton turbines, when the water jet emerges in the air, its velocity decreases downstream and its diameter increases to meet the continuity. In this paper, a physical parameter, the enlarging rate of jet diameter k...In Pelton turbines, when the water jet emerges in the air, its velocity decreases downstream and its diameter increases to meet the continuity. In this paper, a physical parameter, the enlarging rate of jet diameter kDi was introduced and measured experimentally. The measurement of enlarging rate was carried out in three model turbines with different distributing Y-branch and nozzle configurations under various operating conditions. The effect of jet enlarging rate on the unsteady water sheet flow in the rotating buckets has not been investigated so tar. This paper also presents the comparative numerical analysis of the flow in buckets at different enlarging rates of jet. It is shown that the effect of jet enlargement is so large that the flow pattern in the bucket is drastically changed by the latter half of the frames, The jet with large enlarging rate also introduces worse energy behavior to the hydraulic performance of the Pelton turbine. Besides, the phenomenon of jet interference was also discussed by using the results of numerical simulation for one jet. It indicates that the jet with large enlarging rate takes more risk that jet interference may damage the performance of multi-nozzle Pelton turbine.展开更多
文摘To study the relationship between incidence and time course of traumatic intracerebral hematoma enlargement and that between hematoma irregular rate (IR) and hematoma enlargement after brain injury.Methods After brain injury,164 cases with traumatic supratentorial intracerebral hematoma were examined by cranial CT scan within 72 hours thereafter reexamined 120 hours there after so as to compare the hematoma volumes (V1 and V2) and analyze the relation between hematoma IR and hematoma enlargement.Results After brain injury,enlargement of hematoma was confirmed in 70 cases (42.7%),in which the cutpoint for hematoma enlargement was determined as V2/V1=1.45 by using receiver operating characteristic curves (ROC).Hematoma IR had positive correlation with hematoma enlargement (r=0.857,P<0.01).Conclusion Since the incidence of traumatic hematoma enlargement is high,we can tell the possibility of hematoma enlargement based on hematoma IR in order to make a timely reexamination of CT scan and apply active treatments.7 refs,1 tab.
文摘In Pelton turbines, when the water jet emerges in the air, its velocity decreases downstream and its diameter increases to meet the continuity. In this paper, a physical parameter, the enlarging rate of jet diameter kDi was introduced and measured experimentally. The measurement of enlarging rate was carried out in three model turbines with different distributing Y-branch and nozzle configurations under various operating conditions. The effect of jet enlarging rate on the unsteady water sheet flow in the rotating buckets has not been investigated so tar. This paper also presents the comparative numerical analysis of the flow in buckets at different enlarging rates of jet. It is shown that the effect of jet enlargement is so large that the flow pattern in the bucket is drastically changed by the latter half of the frames, The jet with large enlarging rate also introduces worse energy behavior to the hydraulic performance of the Pelton turbine. Besides, the phenomenon of jet interference was also discussed by using the results of numerical simulation for one jet. It indicates that the jet with large enlarging rate takes more risk that jet interference may damage the performance of multi-nozzle Pelton turbine.
