The paper aims to analyze the impacts of punch damper stiffness on equipment base and vibration, andintroduce the development and application of a disc spring damper featured hard-soft-hard variable stiffness. Adamper...The paper aims to analyze the impacts of punch damper stiffness on equipment base and vibration, andintroduce the development and application of a disc spring damper featured hard-soft-hard variable stiffness. Adamper has four damping columns with C-type disc springs whose laminates plate number gradually increases setby set. Compared with its counterparts, this kind of dampers has the advantages of high energy absorption andvibration damping effect, which not only can effectively reduce the vibration of the foundation of punch press,but also prevents the vibration range from increasing. Also, this kind of dampers is of low cost and convenient touse.展开更多
A combined experimental and numerical investigation is carried out to study the performance of a vertical-axis eccentric-disc variable-pitch turbine(VEVT).A scheme of eccentric disc pitch control mechanism based on do...A combined experimental and numerical investigation is carried out to study the performance of a vertical-axis eccentric-disc variable-pitch turbine(VEVT).A scheme of eccentric disc pitch control mechanism based on doubleblock mechanism is proposed.The eccentric control mechanism and the deflection angle control mechanism in the pitch control structure are designed and optimized according to the functional requirements of the turbine,and the three-dimensional model of the turbine is established.Kinematics analysis of the eccentric disc pitch control mechanism is carried out.Kinematics parameters and kinematics equations which can characterize its motion characteristics are derived.Kinematics analysis and simulation are carried out,and the motion law of the corresponding mechanical system is obtained.By analyzing the force and motion of blade of VEVT,the expressions of the important parameters such as deflection angle,attack angle and energy utilization coefficient are obtained.The lateral induced velocity coefficient is acquired by momentum theorem,the hydrodynamic parameters such as energy utilization coefficient are derived,and the hydrodynamic characteristics of VEVT are also obtained.The experimental results show that the turbine has good energy capture capability at different inflow velocities of different sizes and directions,which verifies that VEVT has good self-startup performance and high energy capture efficiency.展开更多
基金supported by the Scientific Research Project of Jieyang Vocational and Technical College(2017JYCKY01)the Innovation and Development Special Fund Project of Jieyang(2017xm014)
文摘The paper aims to analyze the impacts of punch damper stiffness on equipment base and vibration, andintroduce the development and application of a disc spring damper featured hard-soft-hard variable stiffness. Adamper has four damping columns with C-type disc springs whose laminates plate number gradually increases setby set. Compared with its counterparts, this kind of dampers has the advantages of high energy absorption andvibration damping effect, which not only can effectively reduce the vibration of the foundation of punch press,but also prevents the vibration range from increasing. Also, this kind of dampers is of low cost and convenient touse.
基金the National Natural Science Foundation of China(Grant Nos.U1706227 and 51979063)the Harbin Applied Technology Research and Development Project(Grant No.2015RQXXJ016)the Basic Research and Cutting-Edge Technology Projects of State Administration of Science(Grant No.JCKY2019604C003).
文摘A combined experimental and numerical investigation is carried out to study the performance of a vertical-axis eccentric-disc variable-pitch turbine(VEVT).A scheme of eccentric disc pitch control mechanism based on doubleblock mechanism is proposed.The eccentric control mechanism and the deflection angle control mechanism in the pitch control structure are designed and optimized according to the functional requirements of the turbine,and the three-dimensional model of the turbine is established.Kinematics analysis of the eccentric disc pitch control mechanism is carried out.Kinematics parameters and kinematics equations which can characterize its motion characteristics are derived.Kinematics analysis and simulation are carried out,and the motion law of the corresponding mechanical system is obtained.By analyzing the force and motion of blade of VEVT,the expressions of the important parameters such as deflection angle,attack angle and energy utilization coefficient are obtained.The lateral induced velocity coefficient is acquired by momentum theorem,the hydrodynamic parameters such as energy utilization coefficient are derived,and the hydrodynamic characteristics of VEVT are also obtained.The experimental results show that the turbine has good energy capture capability at different inflow velocities of different sizes and directions,which verifies that VEVT has good self-startup performance and high energy capture efficiency.
基金supported by the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-C-202006)Gansu Cheezheng Tibetan Medicine(BUCM-2021-JS-FW-087,Beijing,China).
文摘目的:评价白脉软膏在腰椎间盘突出症(lumbar disc herniation)患者中的疗效与安全性。方法:本研究设计了一项前瞻、随机、双盲、安慰剂对照的多中心临床试验方案。计划招募194例患者,按1:1的比例平均分配至试验组和对照组。患者将接受为期14天的白脉软膏或安慰剂的干预,随后进行为期1周的随访。通过视觉模拟评分法(visual analogue scale score)评估疼痛程度,日本骨科协会评估治疗分数(Japanese Orthopedic Association score)评估功能状态,Likert量表将用于评估麻木程度,此外还将记录应急处理的使用和对健康教育的依从情况。安全性评估将包括实验室检查和不良事件记录。讨论:这项试验将首次对白脉软膏在腰椎间盘突出症患者中进行临床疗效和安全性评价。使用安慰剂的优势在于排除因盲法不充分而导致的偏倚。为了避免由研究对象和研究者的主观因素引起的任何偏倚,对于结局评价者、数据管理人员、统计分析人员以及所有相关研究人员都将实施盲法。本试验结果将为腰椎间盘突出症的治疗以及白脉软膏的未来研究方向提供重要依据。
