The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affec...The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affect the static and dynamic characteristics of the valve isfirst clarified and a criterion for stability is presented. Experiments are designed to test theperformance of the valve. It is necessary to establish a balance between the static and dynamiccharacteristics in deciding the structural parameters. Nevertheless, it is possible to maintain thedynamic response at a fairly high level, while keeping the leakage of the pilot stage at anacceptable level. One of the features of the digital valve is stage control. In stage control thenonlinearities, such as electromagnetic saturation and hysteresis, are greatly reduced. To a largeextent the dynamic response of the valve is decided by the executing cycle of the control algorithm.展开更多
A novel pilot stage valve called simplified 2D valve, which utilizes bothrotary and linear motions of a single spool, is presented. The rotary motion of the spoolincorporating hydraulic resistance bridge, formed by a ...A novel pilot stage valve called simplified 2D valve, which utilizes bothrotary and linear motions of a single spool, is presented. The rotary motion of the spoolincorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening,is utilized as pilot to actuate linear motion of the spool. A criterion for stability is derivedfrom the linear analysis of the valve. Special experiments are designed to acquire the mechanicalstiffness, the pilot leakage and the step response. It is shown that the sectional size of thespiral groove affects the dynamic response and the stiffness contradictorily and is also verysensitive to the pilot leakage. Therefore, it is necessary to establish a balance between the staticand dynamic characteristics in deciding the structural parameters. Nevertheless, it is possible tosustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage atan acceptable level.展开更多
Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the pr...Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the principle,recent achievements,developments and applications of GEM are mainly described.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50075082).
文摘The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affect the static and dynamic characteristics of the valve isfirst clarified and a criterion for stability is presented. Experiments are designed to test theperformance of the valve. It is necessary to establish a balance between the static and dynamiccharacteristics in deciding the structural parameters. Nevertheless, it is possible to maintain thedynamic response at a fairly high level, while keeping the leakage of the pilot stage at anacceptable level. One of the features of the digital valve is stage control. In stage control thenonlinearities, such as electromagnetic saturation and hysteresis, are greatly reduced. To a largeextent the dynamic response of the valve is decided by the executing cycle of the control algorithm.
基金This project is supported by National Natural Science Foundation of China (No.50075082)
文摘A novel pilot stage valve called simplified 2D valve, which utilizes bothrotary and linear motions of a single spool, is presented. The rotary motion of the spoolincorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening,is utilized as pilot to actuate linear motion of the spool. A criterion for stability is derivedfrom the linear analysis of the valve. Special experiments are designed to acquire the mechanicalstiffness, the pilot leakage and the step response. It is shown that the sectional size of thespiral groove affects the dynamic response and the stiffness contradictorily and is also verysensitive to the pilot leakage. Therefore, it is necessary to establish a balance between the staticand dynamic characteristics in deciding the structural parameters. Nevertheless, it is possible tosustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage atan acceptable level.
文摘Gas electron multiplier (GEM) as a novel gas detector,due to it’s simple structure,high performance,well compatibility etc.,is widely used in high-energy physics,nuclear physics and other fields.In this review,the principle,recent achievements,developments and applications of GEM are mainly described.
