Synthesizing the mechanical models of the belt, the driver and the take-up device, the dynamics model was established on the longitudinal vibration of the overall belt conveyor system with finite elemental method, and...Synthesizing the mechanical models of the belt, the driver and the take-up device, the dynamics model was established on the longitudinal vibration of the overall belt conveyor system with finite elemental method, and S-function simulation block of asynchronous motor owing feedback function was built in Matlab/Simulink software, the simulation block indicates that motor rotation speed and its output moment vary with load and time, and the motor is a dynamic feedback system in working process. The state space block was adopted to express model of the belt. Thus it created simulation model of established dynamic model of overall belt conveyor system with Mat- lab/Simulink software, and simulates the course of starting by properly setting simulation parameters, and processes data for visualization.展开更多
The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration ...The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies.展开更多
Design of composites and usage of new polymer materials allows for improvement of constructional properties of belts. Different applications： transmission, conveying or controlling have different meshing in gear. The...Design of composites and usage of new polymer materials allows for improvement of constructional properties of belts. Different applications： transmission, conveying or controlling have different meshing in gear. The work presents meshing model between timing belt and pulley and constructional features of transmission timing belts depending on materials used for their production. While designing timing belt, much attention should be paid to selection of materials, which has significant influence on mechanical properties of belts. This paper attempts to identify the model material and the nature of cooperation of timing belt-pulley; this is basic knowledge for the development of timing belt gear.展开更多
We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivi...We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons. This improvement can reach 37.5% in the low temperature region. The pressure dependence of thermal conductivity is also investigated for different length, width and thickness of few-layer graphene. Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons, b-arthermore, it maybe indicate a so-called pressure-thermM effect in nanomaterials.展开更多
This paper investigates the nonlinear dynamics of network-based dynamical systems where network communication channels of finite data rates are inserted into the closed loops of the control systems. The authors analyz...This paper investigates the nonlinear dynamics of network-based dynamical systems where network communication channels of finite data rates are inserted into the closed loops of the control systems. The authors analyze the bifurcation and chaotic behavior of the non-smooth dynamical systems. The authors first prove that for almost all system parameters there are no periodic orbits. This result distinguishes this type of non-smooth dynamical systems from many others exhibiting border-collision bifurcations. Next, the authors show analytically that the chaotic sets are separated from the region containing the line segment of all fixed points with a finite distance. Finally, the authors employ a simple model to highlight that both the number of clients sharing a common network channel and fluctuations in the available network bandwidth have significant influence on the performance of such dynamical systems.展开更多
文摘Synthesizing the mechanical models of the belt, the driver and the take-up device, the dynamics model was established on the longitudinal vibration of the overall belt conveyor system with finite elemental method, and S-function simulation block of asynchronous motor owing feedback function was built in Matlab/Simulink software, the simulation block indicates that motor rotation speed and its output moment vary with load and time, and the motor is a dynamic feedback system in working process. The state space block was adopted to express model of the belt. Thus it created simulation model of established dynamic model of overall belt conveyor system with Mat- lab/Simulink software, and simulates the course of starting by properly setting simulation parameters, and processes data for visualization.
文摘The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies.
文摘Design of composites and usage of new polymer materials allows for improvement of constructional properties of belts. Different applications： transmission, conveying or controlling have different meshing in gear. The work presents meshing model between timing belt and pulley and constructional features of transmission timing belts depending on materials used for their production. While designing timing belt, much attention should be paid to selection of materials, which has significant influence on mechanical properties of belts. This paper attempts to identify the model material and the nature of cooperation of timing belt-pulley; this is basic knowledge for the development of timing belt gear.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos.11004082 and 11175067the Natural Science Foundation of Guangdong Province under Grant Nos.10451063201005249 and S201101000332the Fundamental Research Funds for the Central Universities,JNU under Grant Nos.21611437 and 50421288
文摘We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons. This improvement can reach 37.5% in the low temperature region. The pressure dependence of thermal conductivity is also investigated for different length, width and thickness of few-layer graphene. Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons, b-arthermore, it maybe indicate a so-called pressure-thermM effect in nanomaterials.
基金supported by an the National Natural Science Foundation of China under Grant No.60804015,and an NSERC grant to the third author
文摘This paper investigates the nonlinear dynamics of network-based dynamical systems where network communication channels of finite data rates are inserted into the closed loops of the control systems. The authors analyze the bifurcation and chaotic behavior of the non-smooth dynamical systems. The authors first prove that for almost all system parameters there are no periodic orbits. This result distinguishes this type of non-smooth dynamical systems from many others exhibiting border-collision bifurcations. Next, the authors show analytically that the chaotic sets are separated from the region containing the line segment of all fixed points with a finite distance. Finally, the authors employ a simple model to highlight that both the number of clients sharing a common network channel and fluctuations in the available network bandwidth have significant influence on the performance of such dynamical systems.
