AIM: To evaluate the efficacy and safety of active removal of silicone oil with low and high viscosity through a 23-gauge transconjunctival cannula using an external vacuum pump.METHODS: This study was conducted as a ...AIM: To evaluate the efficacy and safety of active removal of silicone oil with low and high viscosity through a 23-gauge transconjunctival cannula using an external vacuum pump.METHODS: This study was conducted as a prospective, interventional case series. A total of 22 eyes of 21 patients [1000 centistokes(c St): 17 eyes, 5700 c St:5 eyes] were included in this study. All patients underwent active silicone oil removal via the entire lumen of a 23-gauge microcannula with suction pressure of a650-700 mm Hg vacuum using an external vacuum pump. A tubing adaptor from the Total Plus Pak誖(Alcon,Fort Worth, USA) was used to join the microcannula and silicone vacuum tube connected to an external vacuum pump. Main outcome measures were mean removal time,changes of intraocular pressure(IOP) and visual acuity,and intraoperative and postoperative complications.RESULTS: Mean removal time(min) was 1.49±0.43 for1000 c St and 7. 12 ± 1. 27 for 5700 c St. The IOP was18.57±7.48 mm Hg at baseline, 11.68 ±4.55 mm Hg at day1 postoperatively(P <0.001), and 15.95±4.92, 16.82±3.81,17.41 ±3.50, and 17.09 ±3.01 mm Hg after one week, one month, three months, and six months, respectively. All patients showed improved or stabilized visual acuity.There was no occurrence of intraoperative or postoperative complications during the follow up period.CONCLUSION: This technique for active removal of silicone oil through a 23-gauge cannula using an external vacuum pump is fast, effective, and safe as well as economical for silicone oil with both low and high viscosity in all eyes with pseudophakia, aphakia, or phakia.展开更多
In the printing industry,vacuum pumps play a critical role in sheet feeding and gripping processes.In order to improve the efficiency of vacuum pumps,By analyzing the internal flow field of the vane type vacuum pump,t...In the printing industry,vacuum pumps play a critical role in sheet feeding and gripping processes.In order to improve the efficiency of vacuum pumps,By analyzing the internal flow field of the vane type vacuum pump,the CFD method was used to simulate the internal flow field of the air pump,and it was found that a main vortex was formed near the rotor of the trailing blade.Based on this observation,a new rotor shape design was proposed in this study,which design places arc-shaped depressed on the circumference of the rotor where the main vortex forms.The existence of the depression facilitated forward motion of the main airflow and thus effectively restricting reverse flow.Simulation results demonstrated that the proposed design is able to decrease pressure-induced torque load on the pump,and the reduction increases for an increasing operating speed.For all three operating speeds tested,the reduction in pressure-induced torque ranges from 5%to up to 10%comparing to the original pump.展开更多
Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that ...Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that is not collected will be taken into human bodies via inhalation, which will lead to respiratory diseases. Therefore, it is crucial to design a chalkboard eraser that can collect the dust effectively. If the eraser can be controlled both remotely and manually by people, it can further reduce the amount of dust taken in by human bodies. To achieve remote control, a micro-controller is needed to transfer the infrared radiation (IR) into signals that can control electric motors to move around on the chalkboard. Furthermore, the microfiber is also used as the cleaning material to improve the performance of dust cleaning and collecting. A vacuum pump is needed to create negative pressure between the eraser and the chalkboard so that the eraser can stick to it. The result shows a stronger ability in removing and collecting dust. With the help of the Arduino UNO board, the remote control is successfully achieved, and the eraser can move on the chalkboard freely according to the order.</span>展开更多
A new method for chemical pumping of gases has been developed using reactive alloys of Li with IIA metals in the liquid state. It is an answer to the need for ultra-high and extremely high vacuum without loose solid p...A new method for chemical pumping of gases has been developed using reactive alloys of Li with IIA metals in the liquid state. It is an answer to the need for ultra-high and extremely high vacuum without loose solid particles. Another application of this development is the production of high- and ultra-pure noble gases in a one-step process. Both of these solutions are unprecedented;they are based on a new gas/melt sorption interface that raises the overall bar of technical advances in the field to a higher level, simplifying sorption equipment and leading to cost savings.展开更多
To address the complex spatiotemporal characteristics of impeller axial clearance leakage flow in a liquid-ring vacuum pump,plasma actuation with radial centripetal,circumferential reverse,and counter discharge layout...To address the complex spatiotemporal characteristics of impeller axial clearance leakage flow in a liquid-ring vacuum pump,plasma actuation with radial centripetal,circumferential reverse,and counter discharge layout types was designed to control the leakage flow.The regulation effects and interference mechanisms of plasma actuation on clearance leakage flow were explored.The results show that under plasma flow control of the three layout types,the vacuum degree of the pump changes not obviously,but the shaft power is reduced and the efficiency is improved to a certain extent.Among them,the circumferential reverse has a more obvious control effect on the hydraulic performance of the pump and has more advantages in controlling the medium-and high-intensity leakage flow in the compression zone,while the radial centripetal has a more effective control effect on the low-intensity leakage flow in the transition zone.All three layout types of plasma actuation can effectively weaken the medium-intensity leakage flow near the beginning of the compression zone,but their suppression effect on the high-intensity leakage flow near the end of the compression zone is weak.Due to the weak leakage in the transition region,the plasma actuation induced airflow and low-intensity leakage flow are coupled with each other,which will further aggravate the complexity and variability of the flow in the clearance.For unsteady clearance leakage flow,the circumferential reverse has a more stable control effect.About the control of medium-intensity leakage flow,the radial centripetal plasma actuation effect is better than the circumferential reverse.The research results can provide theoretical and methodological references for the performance optimization of liquid-ring vacuum pumps.展开更多
文摘AIM: To evaluate the efficacy and safety of active removal of silicone oil with low and high viscosity through a 23-gauge transconjunctival cannula using an external vacuum pump.METHODS: This study was conducted as a prospective, interventional case series. A total of 22 eyes of 21 patients [1000 centistokes(c St): 17 eyes, 5700 c St:5 eyes] were included in this study. All patients underwent active silicone oil removal via the entire lumen of a 23-gauge microcannula with suction pressure of a650-700 mm Hg vacuum using an external vacuum pump. A tubing adaptor from the Total Plus Pak誖(Alcon,Fort Worth, USA) was used to join the microcannula and silicone vacuum tube connected to an external vacuum pump. Main outcome measures were mean removal time,changes of intraocular pressure(IOP) and visual acuity,and intraoperative and postoperative complications.RESULTS: Mean removal time(min) was 1.49±0.43 for1000 c St and 7. 12 ± 1. 27 for 5700 c St. The IOP was18.57±7.48 mm Hg at baseline, 11.68 ±4.55 mm Hg at day1 postoperatively(P <0.001), and 15.95±4.92, 16.82±3.81,17.41 ±3.50, and 17.09 ±3.01 mm Hg after one week, one month, three months, and six months, respectively. All patients showed improved or stabilized visual acuity.There was no occurrence of intraoperative or postoperative complications during the follow up period.CONCLUSION: This technique for active removal of silicone oil through a 23-gauge cannula using an external vacuum pump is fast, effective, and safe as well as economical for silicone oil with both low and high viscosity in all eyes with pseudophakia, aphakia, or phakia.
文摘In the printing industry,vacuum pumps play a critical role in sheet feeding and gripping processes.In order to improve the efficiency of vacuum pumps,By analyzing the internal flow field of the vane type vacuum pump,the CFD method was used to simulate the internal flow field of the air pump,and it was found that a main vortex was formed near the rotor of the trailing blade.Based on this observation,a new rotor shape design was proposed in this study,which design places arc-shaped depressed on the circumference of the rotor where the main vortex forms.The existence of the depression facilitated forward motion of the main airflow and thus effectively restricting reverse flow.Simulation results demonstrated that the proposed design is able to decrease pressure-induced torque load on the pump,and the reduction increases for an increasing operating speed.For all three operating speeds tested,the reduction in pressure-induced torque ranges from 5%to up to 10%comparing to the original pump.
文摘Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that is not collected will be taken into human bodies via inhalation, which will lead to respiratory diseases. Therefore, it is crucial to design a chalkboard eraser that can collect the dust effectively. If the eraser can be controlled both remotely and manually by people, it can further reduce the amount of dust taken in by human bodies. To achieve remote control, a micro-controller is needed to transfer the infrared radiation (IR) into signals that can control electric motors to move around on the chalkboard. Furthermore, the microfiber is also used as the cleaning material to improve the performance of dust cleaning and collecting. A vacuum pump is needed to create negative pressure between the eraser and the chalkboard so that the eraser can stick to it. The result shows a stronger ability in removing and collecting dust. With the help of the Arduino UNO board, the remote control is successfully achieved, and the eraser can move on the chalkboard freely according to the order.</span>
文摘A new method for chemical pumping of gases has been developed using reactive alloys of Li with IIA metals in the liquid state. It is an answer to the need for ultra-high and extremely high vacuum without loose solid particles. Another application of this development is the production of high- and ultra-pure noble gases in a one-step process. Both of these solutions are unprecedented;they are based on a new gas/melt sorption interface that raises the overall bar of technical advances in the field to a higher level, simplifying sorption equipment and leading to cost savings.
基金supported by National Natural Science Foundation of China(grant number 52269021)the Red Willow Excellent Youth Project of Lanzhou University of Technologythe Central Government Guides Local Science and Technology Development Fund Projects(23ZYQA0320)。
文摘To address the complex spatiotemporal characteristics of impeller axial clearance leakage flow in a liquid-ring vacuum pump,plasma actuation with radial centripetal,circumferential reverse,and counter discharge layout types was designed to control the leakage flow.The regulation effects and interference mechanisms of plasma actuation on clearance leakage flow were explored.The results show that under plasma flow control of the three layout types,the vacuum degree of the pump changes not obviously,but the shaft power is reduced and the efficiency is improved to a certain extent.Among them,the circumferential reverse has a more obvious control effect on the hydraulic performance of the pump and has more advantages in controlling the medium-and high-intensity leakage flow in the compression zone,while the radial centripetal has a more effective control effect on the low-intensity leakage flow in the transition zone.All three layout types of plasma actuation can effectively weaken the medium-intensity leakage flow near the beginning of the compression zone,but their suppression effect on the high-intensity leakage flow near the end of the compression zone is weak.Due to the weak leakage in the transition region,the plasma actuation induced airflow and low-intensity leakage flow are coupled with each other,which will further aggravate the complexity and variability of the flow in the clearance.For unsteady clearance leakage flow,the circumferential reverse has a more stable control effect.About the control of medium-intensity leakage flow,the radial centripetal plasma actuation effect is better than the circumferential reverse.The research results can provide theoretical and methodological references for the performance optimization of liquid-ring vacuum pumps.
