[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar con...[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar concentration of per- fect and staminate flowers were measured and analyzed in morning and afternoon. [Result] Average nectar quantity and sugar concentration differed insignificantly in morning and afternoon of perfect flowers, which could also be applied to staminate flowers. However, average nectar quantity of perfect flower was 64.09 μI and of staminate flower was 44.07 μl. It is obvious that the two were of extremely signifi- cant differences （t=4.642, P〈0.01）, and the former was significantly higher by 45,43%. On the other hand, average sugar concentration of perfect flower was 48.44% and of staminate flower was 37.16%. The two were of extremely significant differences and the former is higher by 30.36%, compared with the latter. These suggested that nectar quantity and sugar concentration would maintain unchanged in different periods for a day, if nectars are not consumed by pollinators, such as bees and butterflies. In the same period, nectar quantity and sugar concentration of per- fect flowers were higher than those of staminate flowers. [Conclusion] The research provides references for benefits increase of bee farmers and fruit farmers, as well as exploration of bee pollination.展开更多
Based on mechanics to design hollow plastic parison shape,this paper adopted computer and programmable logic controllers(PLCs) to build a three level system,finish the CAD of parison,and control the blow molding seque...Based on mechanics to design hollow plastic parison shape,this paper adopted computer and programmable logic controllers(PLCs) to build a three level system,finish the CAD of parison,and control the blow molding sequentially.Parison thickness was controlled by an electro hydraulic proportional control system,which controls the gap between the parison and the nozzle during the extrusion process by regulating the position of the core bar.Both constant pressure and speed control systems were adopted to control the process of plastic storing and extrusion,and PLC,such as C200H and CQM1,fuzzy modules were adopted.The results show that the part quality of blow molding can be improved greatly.展开更多
Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe...Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe extrusion and parison formation. The constitutive equation of Carreau law was used to describe the polymer melt in the flow domain. The distributions of the velocity, shear rate, viscosity, pressure, thickness and radius are presented with Polyflow. The effect of flow rate and temperature on extrusion swell and parison sag was investigated. The results show that the thickness of the parison increases with increasing flow rate. The thickness and radius of the parison are more sensitive to changes in flow rates than to changes in temperatures.展开更多
基金Supported by National Modern Agriculture (Bee Industry) Technolgy System (CARS-45-SYZ17)~~
文摘[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar concentration of per- fect and staminate flowers were measured and analyzed in morning and afternoon. [Result] Average nectar quantity and sugar concentration differed insignificantly in morning and afternoon of perfect flowers, which could also be applied to staminate flowers. However, average nectar quantity of perfect flower was 64.09 μI and of staminate flower was 44.07 μl. It is obvious that the two were of extremely signifi- cant differences （t=4.642, P〈0.01）, and the former was significantly higher by 45,43%. On the other hand, average sugar concentration of perfect flower was 48.44% and of staminate flower was 37.16%. The two were of extremely significant differences and the former is higher by 30.36%, compared with the latter. These suggested that nectar quantity and sugar concentration would maintain unchanged in different periods for a day, if nectars are not consumed by pollinators, such as bees and butterflies. In the same period, nectar quantity and sugar concentration of per- fect flowers were higher than those of staminate flowers. [Conclusion] The research provides references for benefits increase of bee farmers and fruit farmers, as well as exploration of bee pollination.
文摘Based on mechanics to design hollow plastic parison shape,this paper adopted computer and programmable logic controllers(PLCs) to build a three level system,finish the CAD of parison,and control the blow molding sequentially.Parison thickness was controlled by an electro hydraulic proportional control system,which controls the gap between the parison and the nozzle during the extrusion process by regulating the position of the core bar.Both constant pressure and speed control systems were adopted to control the process of plastic storing and extrusion,and PLC,such as C200H and CQM1,fuzzy modules were adopted.The results show that the part quality of blow molding can be improved greatly.
文摘Swell and sag drawdown significantly influence the high density polyethylene parison. Nu- merical simulations of the flow field of a HDPE melt were performed using the finite element method for the die of plastic pipe extrusion and parison formation. The constitutive equation of Carreau law was used to describe the polymer melt in the flow domain. The distributions of the velocity, shear rate, viscosity, pressure, thickness and radius are presented with Polyflow. The effect of flow rate and temperature on extrusion swell and parison sag was investigated. The results show that the thickness of the parison increases with increasing flow rate. The thickness and radius of the parison are more sensitive to changes in flow rates than to changes in temperatures.
