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
Knowledge representation is a key to the building of expert systems. The performance of knowledge representation methods directly affects the intelligence level and the problem-solving ability of the system. There are...Knowledge representation is a key to the building of expert systems. The performance of knowledge representation methods directly affects the intelligence level and the problem-solving ability of the system. There are various kinds of knowledge representation methods in ESEP3.0. In this paper, the authors introduce the knowledge representation methods, such as structure knowledge, seismological and precursory forecast knowledge, machine learning knowledge, synthetic prediction knowledge, knowledge to validate and verify certainty factors of anomalous evidence and support knowledge, etc. and propose a model for validation of certainty factors of anomalous evidence. The knowledge representation methods represent all kinds of earthquake prediction knowledge well.展开更多
Depression until the current cause is still in further exploration, its pathogenesis and complex tedious, involving genetic, own personality and social environment, the proven mechanism research including monoamine ne...Depression until the current cause is still in further exploration, its pathogenesis and complex tedious, involving genetic, own personality and social environment, the proven mechanism research including monoamine neurotransmitter disorder, hypothalamic pituitary adrenalaxis (HPA) axis dysfunction, brain neurotrophic factors and inflammatory response. The treatment of depression also has some complexity, but the systematic and correct treatment plays a key role in patient recovery. Not only can patients relieve the pain, but also reduce the family and social burden after enabling patients to return to society. The treatment of depression includes drug therapy, psychotherapy, physical therapy, physical and drug combination therapy. Many scholars and medical experts have studied and discussed the current situation and treatment of depression, which is reviewed in this paper. Expect to provide help with the diagnosis and treatment of depression.展开更多
Objective: to explore the curative effect of tubeless percutaneous nephrolithotomy and ordinary minimally invasive percutaneous nephrolithotomy in the treatment of renal calculi. Methods: fifty patients with kidney ca...Objective: to explore the curative effect of tubeless percutaneous nephrolithotomy and ordinary minimally invasive percutaneous nephrolithotomy in the treatment of renal calculi. Methods: fifty patients with kidney calculi who received treatment in our hospital from January 2021 to March 2022 were selected as the research object, and randomly divided into the observation group and the control group. The two groups received different treatment methods. Results: according to the research results, the comprehensive indexes such as postoperative recovery time and hospital stay of the observation group were better than those of the control group, and the difference between the groups was statistically significant (P<0.05). Conclusion: during the treatment of kidney calculi, the effect of tubeless percutaneous renal surgery is more significant, which reduces the incidence of adverse diseases and hospitalization time of patients.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Knowledge representation is a key to the building of expert systems. The performance of knowledge representation methods directly affects the intelligence level and the problem-solving ability of the system. There are various kinds of knowledge representation methods in ESEP3.0. In this paper, the authors introduce the knowledge representation methods, such as structure knowledge, seismological and precursory forecast knowledge, machine learning knowledge, synthetic prediction knowledge, knowledge to validate and verify certainty factors of anomalous evidence and support knowledge, etc. and propose a model for validation of certainty factors of anomalous evidence. The knowledge representation methods represent all kinds of earthquake prediction knowledge well.
文摘Depression until the current cause is still in further exploration, its pathogenesis and complex tedious, involving genetic, own personality and social environment, the proven mechanism research including monoamine neurotransmitter disorder, hypothalamic pituitary adrenalaxis (HPA) axis dysfunction, brain neurotrophic factors and inflammatory response. The treatment of depression also has some complexity, but the systematic and correct treatment plays a key role in patient recovery. Not only can patients relieve the pain, but also reduce the family and social burden after enabling patients to return to society. The treatment of depression includes drug therapy, psychotherapy, physical therapy, physical and drug combination therapy. Many scholars and medical experts have studied and discussed the current situation and treatment of depression, which is reviewed in this paper. Expect to provide help with the diagnosis and treatment of depression.
文摘Objective: to explore the curative effect of tubeless percutaneous nephrolithotomy and ordinary minimally invasive percutaneous nephrolithotomy in the treatment of renal calculi. Methods: fifty patients with kidney calculi who received treatment in our hospital from January 2021 to March 2022 were selected as the research object, and randomly divided into the observation group and the control group. The two groups received different treatment methods. Results: according to the research results, the comprehensive indexes such as postoperative recovery time and hospital stay of the observation group were better than those of the control group, and the difference between the groups was statistically significant (P<0.05). Conclusion: during the treatment of kidney calculi, the effect of tubeless percutaneous renal surgery is more significant, which reduces the incidence of adverse diseases and hospitalization time of patients.
