This paper presents a comparison study of workspace and dexterity of two Tricept units for Reconfigurable Parallel Kinematic Machines （RPKMs）. The modular leg of RPKMs is designed and the RPKMs can be built by chang...This paper presents a comparison study of workspace and dexterity of two Tricept units for Reconfigurable Parallel Kinematic Machines （RPKMs）. The modular leg of RPKMs is designed and the RPKMs can be built by changing tile setting of modules. A compositive kinematic model is developed accordingly. The inverse kinematics and Jacobian of these two Trieept units are analyzed. Considering workspaee volume and dexterity, the effeets of geometric size of some modules on the two Trieept units are discussed. In the end, comparison results of these two Tricept units are. given. The eomparison of two kinds of Parallel Kinematic Machines （PKMs） can be of help in the design and configuration planning of the RPKMs.展开更多
In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonli...In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.展开更多
文摘This paper presents a comparison study of workspace and dexterity of two Tricept units for Reconfigurable Parallel Kinematic Machines （RPKMs）. The modular leg of RPKMs is designed and the RPKMs can be built by changing tile setting of modules. A compositive kinematic model is developed accordingly. The inverse kinematics and Jacobian of these two Trieept units are analyzed. Considering workspaee volume and dexterity, the effeets of geometric size of some modules on the two Trieept units are discussed. In the end, comparison results of these two Tricept units are. given. The eomparison of two kinds of Parallel Kinematic Machines （PKMs） can be of help in the design and configuration planning of the RPKMs.
基金supported from the research projects of the Environmental Public Welfare Industry in China (201509001,201409005)the National Science and Technology Support Program of China (2014BAC21B01)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB05010500)the Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control (18K03ESPCP)the EU-project AMIS (Fate and Impact of Atmospheric Pollutants,PIRSES-GA-2011295132)
文摘In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.
