As a high gravity(HIGEE)unit,the rotating packed bed(RPB)uses centrifugal force to intensify mass transfer.Zigzag rotating bed(RZB)is a new type of HIGEE unit.The rotor of RZB consists of stationary discs and rotating...As a high gravity(HIGEE)unit,the rotating packed bed(RPB)uses centrifugal force to intensify mass transfer.Zigzag rotating bed(RZB)is a new type of HIGEE unit.The rotor of RZB consists of stationary discs and rotating discs,forming zigzag channels for liquid-gas flow and mass transfer.As in RPBs,some hydrodynamic behavior in RZB is interesting but no satisfactory explanation.In this study,the experiments were carried on in a RZB unit with a rotor of 600 mm in diameter using air-water system.The gas pressure drop and power consumption were measured with two types of rotating baffle for RZB rotors,one with perforations and another with shutter openings. The circumferential velocities of gas were measured with a five-hole Pitot probe.The pressure drop decreased rapidly when the liquid was introduced to the rotor,because the circumferential velocity of the liquid droplets was lower than that of the gas,reducing the circumferential velocity of gas and the centrifugal pressure drop.The power consumption decreased first when the gas entered the RZB rotor,because the gas with higher circumferential velocity facilitates the rotation of baffles.展开更多
Objective: To study the changes of partial pressure of brain tissue oxygen (PbtO 2) and brain temperature in acute phase of severe head injury during mild hypothermia therapy and the clinical significance. Methods: On...Objective: To study the changes of partial pressure of brain tissue oxygen (PbtO 2) and brain temperature in acute phase of severe head injury during mild hypothermia therapy and the clinical significance. Methods: One hundred and sixteen patients with severe head injury were selected and divided into a mild hypothermia group (n=58), and a control group (n=58) according to odd and even numbers of hospitalization. While mild hypothermia therapy was performed PbtO 2 and brain temperature were monitored for 1 7 days (mean=86 hours), simultaneously, the intracranial pressure, rectum temperature, cerebral perfusion pressure, PaO 2 and PaCO 2 were also monitored. The patients were followed up for 6 months and the prognosis was evaluated with GOS (Glasgow outcome scale). Results: The mean value of PbtO 2 within 24 hour monitoring in the 116 patients was 13.7 mm Hg ± 4.94 mm Hg , lower than the normal value (16 mm Hg ± 40 mm Hg ) The time of PbtO 2 recovering to the normal value in the mild hypothermia group was shortened by 10± 4.15 hours compared with the control group (P< 0.05 ). The survival rate of the mild hypothermia group was 60.43 %, higher than that of the control group ( 46.55 %). After the recovery of the brain temperature, PbtO 2 increased with the rise of the brain temperature. Conclusions: Mild hypothermia can improve the survival rate of severe head injury. The technique of monitoring PbtO 2 and the brain temperature is safe and reliable, and has important clinical significance in judging disease condition and instructing clinical therapy.展开更多
基金Supported by the Natural Science Foundation of Zhejiang Province（Y406239）
文摘As a high gravity(HIGEE)unit,the rotating packed bed(RPB)uses centrifugal force to intensify mass transfer.Zigzag rotating bed(RZB)is a new type of HIGEE unit.The rotor of RZB consists of stationary discs and rotating discs,forming zigzag channels for liquid-gas flow and mass transfer.As in RPBs,some hydrodynamic behavior in RZB is interesting but no satisfactory explanation.In this study,the experiments were carried on in a RZB unit with a rotor of 600 mm in diameter using air-water system.The gas pressure drop and power consumption were measured with two types of rotating baffle for RZB rotors,one with perforations and another with shutter openings. The circumferential velocities of gas were measured with a five-hole Pitot probe.The pressure drop decreased rapidly when the liquid was introduced to the rotor,because the circumferential velocity of the liquid droplets was lower than that of the gas,reducing the circumferential velocity of gas and the centrifugal pressure drop.The power consumption decreased first when the gas entered the RZB rotor,because the gas with higher circumferential velocity facilitates the rotation of baffles.
文摘Objective: To study the changes of partial pressure of brain tissue oxygen (PbtO 2) and brain temperature in acute phase of severe head injury during mild hypothermia therapy and the clinical significance. Methods: One hundred and sixteen patients with severe head injury were selected and divided into a mild hypothermia group (n=58), and a control group (n=58) according to odd and even numbers of hospitalization. While mild hypothermia therapy was performed PbtO 2 and brain temperature were monitored for 1 7 days (mean=86 hours), simultaneously, the intracranial pressure, rectum temperature, cerebral perfusion pressure, PaO 2 and PaCO 2 were also monitored. The patients were followed up for 6 months and the prognosis was evaluated with GOS (Glasgow outcome scale). Results: The mean value of PbtO 2 within 24 hour monitoring in the 116 patients was 13.7 mm Hg ± 4.94 mm Hg , lower than the normal value (16 mm Hg ± 40 mm Hg ) The time of PbtO 2 recovering to the normal value in the mild hypothermia group was shortened by 10± 4.15 hours compared with the control group (P< 0.05 ). The survival rate of the mild hypothermia group was 60.43 %, higher than that of the control group ( 46.55 %). After the recovery of the brain temperature, PbtO 2 increased with the rise of the brain temperature. Conclusions: Mild hypothermia can improve the survival rate of severe head injury. The technique of monitoring PbtO 2 and the brain temperature is safe and reliable, and has important clinical significance in judging disease condition and instructing clinical therapy.
